Publications 2000

@article{messinger_towards_2000,
	title = {Towards understanding the chemistry of photosynthetic oxygen evolution: dynamic structural changes, redox states and substrate water binding of the {Mn} cluster in photosystem {II}},
	volume = {1459},
	issn = {0005-2728},
	shorttitle = {Towards understanding the chemistry of photosynthetic oxygen evolution},
	url = {https://www.sciencedirect.com/science/article/pii/S0005272800001870},
	doi = {10.1016/S0005-2728(00)00187-0},
	abstract = {This mini-review summarizes my postdoctoral research in the labs of T. Wydrzynski/C.B. Osmond, J.H.A. Nugent/M.C.W. Evans and V.K. Yachandra/K. Sauer/M.P. Klein. The results are reported in the context of selected data from the literature. Special emphasis is given to the mode of substrate water binding, Mn oxidation states and the structures of the Mn cluster in the four (meta)stable redox states of the oxygen evolving complex. The paper concludes with a working model for the mechanism of photosynthetic water oxidation that combines μ-oxo bridge oxidation in the S3 state (V.K. Yachandra, K. Sauer, M.P. Klein, Chem. Rev. 96 (1996) 2927–2950) with O-O bond formation between two terminal Mn-hydroxo ligands during the S3→(S4)→S0 transition.},
	number = {2},
	urldate = {2024-11-29},
	journal = {Biochimica et Biophysica Acta (BBA) - Bioenergetics},
	author = {Messinger, Johannes},
	month = aug,
	year = {2000},
	keywords = {Manganese cluster, Oxygen evolution, Photosystem II, Water oxidation},
	pages = {481--488},
}

This mini-review summarizes my postdoctoral research in the labs of T. Wydrzynski/C.B. Osmond, J.H.A. Nugent/M.C.W. Evans and V.K. Yachandra/K. Sauer/M.P. Klein. The results are reported in the context of selected data from the literature. Special emphasis is given to the mode of substrate water binding, Mn oxidation states and the structures of the Mn cluster in the four (meta)stable redox states of the oxygen evolving complex. The paper concludes with a working model for the mechanism of photosynthetic water oxidation that combines μ-oxo bridge oxidation in the S3 state (V.K. Yachandra, K. Sauer, M.P. Klein, Chem. Rev. 96 (1996) 2927–2950) with O-O bond formation between two terminal Mn-hydroxo ligands during the S3→(S4)→S0 transition.

@article{kang_predicted_2000,
	title = {Predicted {Drop} in {Gene} {Diversity} {Over} {Generations} in the {Population} {Where} the {Fertility} {Varies} {Among} {Individuals}},
	volume = {50},
	abstract = {Gene diversity and inbreeding of seed crop over generations were derived and predicted as a function of fertility variation and population sizes in forest tree populations. Gene diversity was calculated in terms of group coancestry. Fertility differences were described by sibling coefficient, which is the probability that two genes originate from the same parent, compared to a situation where all parents give rise to the same number of offspring. Fertility data were collected in a finite population, and calculations were made for the case of a constant breeding population size. The change of status number could be associated with the sibling coefficient. Predictions over five generations showed that group coancestry and inbreeding accumulated fast at the first early shifts. Relative status number declined very fast over generations. The increase of inbreeding and group coancestry was accelerated by fertility variation, and the accumulation was slightly faster and higher if fertility of both genders varied than if maternal fertility was kept constant. Gene diversity decreased faster if fertility variation was large, and maintained higher if the effective population size was reasonably large. Breeding programs that use closely related genotypes lead to the decrease of effective number (i.e., drop in gene diversity) over generations and do not provide a sustainable long-term breeding strategy.},
	language = {en},
	journal = {Silvae Genetica},
	author = {Kang, K S and Bila, A D and Lindgren, D and Choi, W Y},
	month = dec,
	year = {2000},
	keywords = {⛔ No DOI found},
	pages = {200--205},
}

Gene diversity and inbreeding of seed crop over generations were derived and predicted as a function of fertility variation and population sizes in forest tree populations. Gene diversity was calculated in terms of group coancestry. Fertility differences were described by sibling coefficient, which is the probability that two genes originate from the same parent, compared to a situation where all parents give rise to the same number of offspring. Fertility data were collected in a finite population, and calculations were made for the case of a constant breeding population size. The change of status number could be associated with the sibling coefficient. Predictions over five generations showed that group coancestry and inbreeding accumulated fast at the first early shifts. Relative status number declined very fast over generations. The increase of inbreeding and group coancestry was accelerated by fertility variation, and the accumulation was slightly faster and higher if fertility of both genders varied than if maternal fertility was kept constant. Gene diversity decreased faster if fertility variation was large, and maintained higher if the effective population size was reasonably large. Breeding programs that use closely related genotypes lead to the decrease of effective number (i.e., drop in gene diversity) over generations and do not provide a sustainable long-term breeding strategy.

@article{wu_analysis_2000,
	title = {Analysis of half-diallel mating design with missing crosses: {Theory} and {SAS} program for testing and estimating {GCA} and {SCA} fixed effects},
	volume = {49},
	shorttitle = {Analysis of half-diallel mating design with missing crosses},
	abstract = {The half-diallel mating design, particularly a series of disconnected half-diallels has been widely adopted as a mating design for estimating genetic parameters and for future selection in many commercially important tree species. Standard commercial statistical packages do not allow direct specification of the linear model associated with the half-diallel design and therefore are not capable of analysing diallel mating designs, even for balanced diallel matings (no missing crosses). Published special computer programs for diallel analyses do not provide an adequate solution for GCA and SCA fixed effects in diallels with missing crosses. This paper presents the least squares theory for analysing half-diallel mating designs with missing crosses, and a SAS computer program (DIAFIXED.SAS), developed to test the significance of GCA and SCA effects and estimate the GCA and SCA fixed effects. The program is flexible enough to accommodate different number of parents, multiple environments and missing individual trees as well as missing whole plots. The DIAFIXED.SAS output includes (1) hypothesis testing for GCA and SCA fixed effects and environmental effects, (2) estimates of GCA and SCA fixed effects, (3) estimates of standard errors of GCA and SCA fixed effects. Results from a 6 by 6 half-diallel for radiata pine planted in two sites are also presented.},
	journal = {Silvae Genetica},
	author = {Wu, H.X. and Matheson, Alastair},
	month = jan,
	year = {2000},
	keywords = {⛔ No DOI found},
	pages = {130--136},
}

The half-diallel mating design, particularly a series of disconnected half-diallels has been widely adopted as a mating design for estimating genetic parameters and for future selection in many commercially important tree species. Standard commercial statistical packages do not allow direct specification of the linear model associated with the half-diallel design and therefore are not capable of analysing diallel mating designs, even for balanced diallel matings (no missing crosses). Published special computer programs for diallel analyses do not provide an adequate solution for GCA and SCA fixed effects in diallels with missing crosses. This paper presents the least squares theory for analysing half-diallel mating designs with missing crosses, and a SAS computer program (DIAFIXED.SAS), developed to test the significance of GCA and SCA effects and estimate the GCA and SCA fixed effects. The program is flexible enough to accommodate different number of parents, multiple environments and missing individual trees as well as missing whole plots. The DIAFIXED.SAS output includes (1) hypothesis testing for GCA and SCA fixed effects and environmental effects, (2) estimates of GCA and SCA fixed effects, (3) estimates of standard errors of GCA and SCA fixed effects. Results from a 6 by 6 half-diallel for radiata pine planted in two sites are also presented.

@article{wu_study_2000,
	title = {Study of early selection in tree breeding: 3. {A} case study using early information to enhance selection efficiency in late trait in lodgepole pine ({Pinus} contorta spp. {Latifolia})},
	volume = {49},
	shorttitle = {Study of early selection in tree breeding},
	abstract = {We present a selection procedure that combines early performance from retrospective study and late performance from field testing into an index designed for enhancing the selection efficiency of the late performance. The prerequisite is that early performance from retrospective study and late performance from field testing must correlate genetically. This selection index procedure is particularly applicable when practical considerations make seedling selection of early traits preferable. An example is the study of biomass partitioning where young trees could offer a solution for large scale evaluation and serve as a useful first approximation to what might be expected in older trees. To numerically illustrate this selection procedure, we present a case study of retrospective early selection in 110 open-pollinated families from Alberta lodgepole pine (Pinus contorta spp. latifolia). Twenty-eight glasshouse traits in seedlings and the 9-year tree height of their siblings on four sites were conceived as the early and late traits, respectively. Five greenhouse traits having highest genetic correlations with overall field performance were selected and indices of one and two traits from these five glasshouse traits with 9-year tree height averaged 3.0\% and 6\% more efficient, respectively, relative to selection based on 9-year tree height alone. 24 seedling traits which had highest correlations with the field site height were selected for combination with 9-year tree height of one site. Their efficiencies, relative to selection based on 9-year tree height alone, for indices of one and two of glasshouse traits averaged 40\% and 55\% greater, respectively, than selection based on 9-year tree height alone. This demonstrates the potential of early retrospective genetic study to enhance later mature selection.},
	journal = {Silvae Genetica},
	author = {Wu, H.X. and Yeh, Francis and Pharis, R.P. and Dhir, N. and Dancik, Bruce},
	month = jan,
	year = {2000},
	keywords = {⛔ No DOI found},
	pages = {152--158},
}

We present a selection procedure that combines early performance from retrospective study and late performance from field testing into an index designed for enhancing the selection efficiency of the late performance. The prerequisite is that early performance from retrospective study and late performance from field testing must correlate genetically. This selection index procedure is particularly applicable when practical considerations make seedling selection of early traits preferable. An example is the study of biomass partitioning where young trees could offer a solution for large scale evaluation and serve as a useful first approximation to what might be expected in older trees. To numerically illustrate this selection procedure, we present a case study of retrospective early selection in 110 open-pollinated families from Alberta lodgepole pine (Pinus contorta spp. latifolia). Twenty-eight glasshouse traits in seedlings and the 9-year tree height of their siblings on four sites were conceived as the early and late traits, respectively. Five greenhouse traits having highest genetic correlations with overall field performance were selected and indices of one and two traits from these five glasshouse traits with 9-year tree height averaged 3.0% and 6% more efficient, respectively, relative to selection based on 9-year tree height alone. 24 seedling traits which had highest correlations with the field site height were selected for combination with 9-year tree height of one site. Their efficiencies, relative to selection based on 9-year tree height alone, for indices of one and two of glasshouse traits averaged 40% and 55% greater, respectively, than selection based on 9-year tree height alone. This demonstrates the potential of early retrospective genetic study to enhance later mature selection.

@article{overmyer_ozone-sensitive_2000,
	title = {Ozone-{Sensitive} {Arabidopsis} rcd1 {Mutant} {Reveals} {Opposite} {Roles} for {Ethylene} and {Jasmonate} {Signaling} {Pathways} in {Regulating} {Superoxide}-{Dependent} {Cell} {Death}},
	volume = {12},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC149124/},
	doi = {10/bmk4p4},
	abstract = {We have isolated a codominant Arabidopsis mutant, radical-induced cell death1 (rcd1), in which ozone (O[3] ) and extracellular superoxide (O[2] [•−] ), but not hydrogen peroxide, induce cellular O[2] [•−]  accumulation ...},
	language = {en},
	number = {10},
	urldate = {2021-11-08},
	journal = {The Plant Cell},
	author = {Overmyer, Kirk and Tuominen, Hannele and Kettunen, Reetta and Betz, Christian and Langebartels, Christian and Sandermann, Heinrich and Jr and Kangasjärvi, Jaakko},
	month = oct,
	year = {2000},
	pmid = {11041881},
	note = {Publisher: Oxford University Press},
	pages = {1849},
}

We have isolated a codominant Arabidopsis mutant, radical-induced cell death1 (rcd1), in which ozone (O[3] ) and extracellular superoxide (O[2] [•−] ), but not hydrogen peroxide, induce cellular O[2] [•−] accumulation ...

@article{strand_decreased_2000,
	title = {Decreased expression of two key enzymes in the sucrose biosynthesis pathway, cytosolic fructose-1,6-bisphosphatase and sucrose phosphate synthase, has remarkably different consequences for photosynthetic carbon metabolism in transgenic {Arabidopsis} thaliana},
	volume = {23},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2000.00847.x},
	doi = {10/fpq9sb},
	abstract = {Photosynthetic carbon metabolism was investigated in antisense Arabidopsis lines with decreased expression of sucrose phosphate synthase (SPS) and cytosolic fructose-1,6-bisphosphatase (cFBPase). In the light, triose phosphates are exported from the chloroplast and converted to sucrose via cFBPase and SPS. At night, starch is degraded to glucose, exported and converted to sucrose via SPS. cFBPase therefore lies upstream and SPS downstream of the point at which the pathways for sucrose synthesis in the day and night converge. Decreased cFBPase expression led to inhibition of sucrose synthesis; accumulation of phosphorylated intermediates; Pi-limitation of photosynthesis; and stimulation of starch synthesis. The starch was degraded to maintain higher levels of sugars and a higher rate of sucrose export during the night. This resembles the response in other species when expression of enzymes in the upper part of the sucrose biosynthesis pathway is reduced. Decreased expression of SPS inhibited sucrose synthesis, but phosphorylated intermediates did not accumulate and carbon partitioning was not redirected towards starch. Sugar levels and sucrose export was decreased during the night as well as during the day. Although ribulose-1,5-bisphosphate regeneration and photosynthesis were inhibited, the PGA/triose-P ratio remained low and the ATP/ADP ratio high, showing that photosynthesis was not limited by the rate at which Pi was recycled during end-product synthesis. Two novel responses counteracted the decrease in SPS expression and explain why phosphorylated intermediates did not accumulate, and why allocation was not altered in the antisense SPS lines. Firstly, a threefold decrease of PPi and a shift of the UDP-glucose/hexose phosphate ratio favoured sucrose synthesis and prevented the accumulation of phosphorylated intermediates. Secondly, there was no increase of AGPase activity relative to cFBPase activity, which would prevent a shift in carbon allocation towards starch synthesis. These responses are presumably triggered when sucrose synthesis is decreased in the night, as well as by day.},
	language = {en},
	number = {6},
	urldate = {2021-11-08},
	journal = {The Plant Journal},
	author = {Strand, Åsa and Zrenner, Rita and Trevanion, Stephen and Stitt, Mark and Gustafsson, Petter and Gardeström, Per},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2000.00847.x},
	keywords = {6-bisphosphatase, Arabidopsis, carbon metabolism, cytosolic fructose-1, sucrose phosphate synthase},
	pages = {759--770},
}

Photosynthetic carbon metabolism was investigated in antisense Arabidopsis lines with decreased expression of sucrose phosphate synthase (SPS) and cytosolic fructose-1,6-bisphosphatase (cFBPase). In the light, triose phosphates are exported from the chloroplast and converted to sucrose via cFBPase and SPS. At night, starch is degraded to glucose, exported and converted to sucrose via SPS. cFBPase therefore lies upstream and SPS downstream of the point at which the pathways for sucrose synthesis in the day and night converge. Decreased cFBPase expression led to inhibition of sucrose synthesis; accumulation of phosphorylated intermediates; Pi-limitation of photosynthesis; and stimulation of starch synthesis. The starch was degraded to maintain higher levels of sugars and a higher rate of sucrose export during the night. This resembles the response in other species when expression of enzymes in the upper part of the sucrose biosynthesis pathway is reduced. Decreased expression of SPS inhibited sucrose synthesis, but phosphorylated intermediates did not accumulate and carbon partitioning was not redirected towards starch. Sugar levels and sucrose export was decreased during the night as well as during the day. Although ribulose-1,5-bisphosphate regeneration and photosynthesis were inhibited, the PGA/triose-P ratio remained low and the ATP/ADP ratio high, showing that photosynthesis was not limited by the rate at which Pi was recycled during end-product synthesis. Two novel responses counteracted the decrease in SPS expression and explain why phosphorylated intermediates did not accumulate, and why allocation was not altered in the antisense SPS lines. Firstly, a threefold decrease of PPi and a shift of the UDP-glucose/hexose phosphate ratio favoured sucrose synthesis and prevented the accumulation of phosphorylated intermediates. Secondly, there was no increase of AGPase activity relative to cFBPase activity, which would prevent a shift in carbon allocation towards starch synthesis. These responses are presumably triggered when sucrose synthesis is decreased in the night, as well as by day.

@article{hurry_role_2000,
	title = {The role of inorganic phosphate in the development of freezing tolerance and the acclimatization of photosynthesis to low temperature is revealed by the pho mutants of {Arabidopsis} thaliana},
	volume = {24},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2000.00888.x},
	doi = {10/c6xzqg},
	abstract = {Low temperature inhibits sucrose synthesis, leading to a phosphate-limitation of photosynthesis. We have used the Arabidopsis pho1-2 and pho2-1 mutants with decreased and increased shoot phosphate, respectively, to investigate whether low phosphate triggers cold acclimatization of photosynthetic carbon metabolism. Wild-type Arabidopsis, pho1-2 and pho2-1 were grown at 23°C and transferred to 5°C to investigate acclimatization in pre-existing leaves and in new leaves developing at 5°C. The development of frost tolerance and the accumulation of proline and sugars was unaltered or improved in pho1-2, and impaired in pho2-1. Sucrose phosphate synthase and cytoplasmic fructose-1,6-bisphosphatase activity and protein increase after transfer to 5°C. This increase was accentuated in pho1-2 and attenuated in pho2-1. RBCS and LHCB2 transcript levels decrease in pre-formed wild-type leaves after transfer to 5°C and recover in new leaves that develop at 5°C. The initial decrease was attenuated in pho1-2, and accentuated in pho2-1, where the recovery in new leaves was also suppressed. Rubisco activity increased in wild-type leaves that developed at 5°C. This increase was accentuated in pho1-2 and absent in pho2-1. NADP-glyceraldehyde-3-phosphate dehydrogenase, plastidic fructose-1,6-bisphosphatase and aldolase activity increase relative to phosphoglycerate kinase, transketolase and phosphoribulokinase in wild-type leaves at 5°C. This shift was accentuated in pho1-2 and reversed in pho2-1. Transcript levels for COR genes increase transiently 1 day after transfer to 5°C but were very low in leaves that developed at 5°C in wild-type Arabidopsis, pho1-2 and pho2-1. We conclude that low phosphate plays an important role in triggering cold acclimatization of leaves, leading in particular to an increase of Rubisco expression, changes in other Calvin cycle enzymes to minimize sequestration of phosphate in metabolites, and increased expression of sucrose biosynthesis enzymes.},
	language = {en},
	number = {3},
	urldate = {2021-11-08},
	journal = {The Plant Journal},
	author = {Hurry, Vaughan and Strand, Åsa and Furbank, Robert and Stitt, Mark},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2000.00888.x},
	keywords = {Arabidopsis, cold acclimatization, low temperature, phosphate, photosynthesis, sucrose synthesis},
	pages = {383--396},
}

Low temperature inhibits sucrose synthesis, leading to a phosphate-limitation of photosynthesis. We have used the Arabidopsis pho1-2 and pho2-1 mutants with decreased and increased shoot phosphate, respectively, to investigate whether low phosphate triggers cold acclimatization of photosynthetic carbon metabolism. Wild-type Arabidopsis, pho1-2 and pho2-1 were grown at 23°C and transferred to 5°C to investigate acclimatization in pre-existing leaves and in new leaves developing at 5°C. The development of frost tolerance and the accumulation of proline and sugars was unaltered or improved in pho1-2, and impaired in pho2-1. Sucrose phosphate synthase and cytoplasmic fructose-1,6-bisphosphatase activity and protein increase after transfer to 5°C. This increase was accentuated in pho1-2 and attenuated in pho2-1. RBCS and LHCB2 transcript levels decrease in pre-formed wild-type leaves after transfer to 5°C and recover in new leaves that develop at 5°C. The initial decrease was attenuated in pho1-2, and accentuated in pho2-1, where the recovery in new leaves was also suppressed. Rubisco activity increased in wild-type leaves that developed at 5°C. This increase was accentuated in pho1-2 and absent in pho2-1. NADP-glyceraldehyde-3-phosphate dehydrogenase, plastidic fructose-1,6-bisphosphatase and aldolase activity increase relative to phosphoglycerate kinase, transketolase and phosphoribulokinase in wild-type leaves at 5°C. This shift was accentuated in pho1-2 and reversed in pho2-1. Transcript levels for COR genes increase transiently 1 day after transfer to 5°C but were very low in leaves that developed at 5°C in wild-type Arabidopsis, pho1-2 and pho2-1. We conclude that low phosphate plays an important role in triggering cold acclimatization of leaves, leading in particular to an increase of Rubisco expression, changes in other Calvin cycle enzymes to minimize sequestration of phosphate in metabolites, and increased expression of sucrose biosynthesis enzymes.

@article{jansson_arabidopsis_2000,
	title = {An {Arabidopsis} thaliana protein homologous to cyanobacterial high-light-inducible proteins},
	volume = {42},
	issn = {1573-5028},
	url = {https://doi.org/10.1023/A:1006365213954},
	doi = {10/fkkqd2},
	abstract = {An Arabidopsis thaliana cDNA clone encoding a novel 110 amino acid thylakoid protein has been sequenced. The in vitro synthesized protein is taken up by intact chloroplasts, inserted into the thylakoid membrane and the transit peptide is cleaved off during this process. The mature protein is predicted to contain 69 amino acids, to form one membrane-spanning α-helix and to have its N-terminus at the stromal side of the thylakoid membrane. The protein showed similarity to the LHC, ELIP and PsbS proteins of higher plants, but more pronounced to the high-light-inducible proteins (HLIPs) of cyanobacteria and red algae, to which no homologue previously has been detected in higher plants. As for HLIP and ELIP, high light increases the mRNA levels of the corresponding gene. Sequence comparisons indicate that the protein may bind chlorophyll and form dimers in the thylakoid membrane. The level of expression of the protein seems to be far lower than that of normal PSI and PSII subunits.},
	language = {en},
	number = {2},
	urldate = {2021-11-08},
	journal = {Plant Molecular Biology},
	author = {Jansson, Stefan and Andersson, Jenny and Jung Kim, Soo and Jackowski, Grzegorz},
	month = jan,
	year = {2000},
	pages = {345--351},
}

An Arabidopsis thaliana cDNA clone encoding a novel 110 amino acid thylakoid protein has been sequenced. The in vitro synthesized protein is taken up by intact chloroplasts, inserted into the thylakoid membrane and the transit peptide is cleaved off during this process. The mature protein is predicted to contain 69 amino acids, to form one membrane-spanning α-helix and to have its N-terminus at the stromal side of the thylakoid membrane. The protein showed similarity to the LHC, ELIP and PsbS proteins of higher plants, but more pronounced to the high-light-inducible proteins (HLIPs) of cyanobacteria and red algae, to which no homologue previously has been detected in higher plants. As for HLIP and ELIP, high light increases the mRNA levels of the corresponding gene. Sequence comparisons indicate that the protein may bind chlorophyll and form dimers in the thylakoid membrane. The level of expression of the protein seems to be far lower than that of normal PSI and PSII subunits.

@article{kleinow_functional_2000,
	title = {Functional identification of an {Arabidopsis} {Snf4} ortholog by screening for heterologous multicopy suppressors of snf4 deficiency in yeast},
	volume = {23},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2000.00809.x},
	doi = {10/btmg6n},
	abstract = {Yeast Snf4 is a prototype of activating γ-subunits of conserved Snf1/AMPK-related protein kinases (SnRKs) controlling glucose and stress signaling in eukaryotes. The catalytic subunits of Arabidopsis SnRKs, AKIN10 and AKIN11, interact with Snf4 and suppress the snf1 and snf4 mutations in yeast. By expression of an Arabidopsis cDNA library in yeast, heterologous multicopy snf4 suppressors were isolated. In addition to AKIN10 and AKIN11, the deficiency of yeast snf4 mutant to grown on non-fermentable carbon source was suppressed by Arabidopsis Myb30, CAAT-binding factor Hap3b, casein kinase I, zinc-finger factors AZF2 and ZAT10, as well as orthologs of hexose/UDP-hexose transporters, calmodulin, SMC1-cohesin and Snf4. Here we describe the characterization of AtSNF4, a functional Arabidopsis Snf4 ortholog, that interacts with yeast Snf1 and specifically binds to the C-terminal regulatory domain of Arabidopsis SnRKs AKIN10 and AKIN11.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {The Plant Journal},
	author = {Kleinow, Tatjana and Bhalerao, Rishikesh and Breuer, Frank and Umeda, Masaaki and Salchert, Klaus and Koncz, Csaba},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2000.00809.x},
	keywords = {Snf1-related protein kinases, glucose signaling, protein interaction, suppressors of snf4, yeast two-hybrid system},
	pages = {115--122},
}

Yeast Snf4 is a prototype of activating γ-subunits of conserved Snf1/AMPK-related protein kinases (SnRKs) controlling glucose and stress signaling in eukaryotes. The catalytic subunits of Arabidopsis SnRKs, AKIN10 and AKIN11, interact with Snf4 and suppress the snf1 and snf4 mutations in yeast. By expression of an Arabidopsis cDNA library in yeast, heterologous multicopy snf4 suppressors were isolated. In addition to AKIN10 and AKIN11, the deficiency of yeast snf4 mutant to grown on non-fermentable carbon source was suppressed by Arabidopsis Myb30, CAAT-binding factor Hap3b, casein kinase I, zinc-finger factors AZF2 and ZAT10, as well as orthologs of hexose/UDP-hexose transporters, calmodulin, SMC1-cohesin and Snf4. Here we describe the characterization of AtSNF4, a functional Arabidopsis Snf4 ortholog, that interacts with yeast Snf1 and specifically binds to the C-terminal regulatory domain of Arabidopsis SnRKs AKIN10 and AKIN11.

@article{yamaguchi_activation_2000,
	title = {Activation of {CDK}-activating kinase is dependent on interaction with {H}-type cyclins in plants},
	volume = {24},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2000.00846.x},
	doi = {10/cxkrs9},
	abstract = {cDNAs encoding cyclin H homologs were isolated from poplar (Populus tremulax tremuloides) and rice (Oryza sativa) plants, and were designated Pt;cycH;1 and Os;cycH;1, respectively. The deduced amino-acid sequences showed 40–60\% similarity to human cyclin H and Schizosaccharomyces pombe Mcs2, with higher similarity in the cyclin box region. While Pt;cycH;1 and Os;cycH;1 were expressed in all tissues examined, the transcripts accumulated abundantly in dividing cells. Expression of Os;cycH;1 was abundant in the S-phase in partially synchronized suspension cells, and was induced by submergence in internodes of deepwater rice. A yeast two-hybrid assay demonstrated that both Pt;CycH;1 and Os;CycH;1 were able to interact with rice R2 kinase, which is structurally and functionally similar to cyclin-dependent kinase (CDK)-activating kinase (CAK) of vertebrates. Moreover, an in vitro pull-down assay showed that Os;CycH;1 specifically bound to R2 but not to other rice CDKs. When R2 was expressed in budding yeast CAK mutant, the suppression activity in terms of temperature-sensitivity was enhanced by co-expression with Os;cycH;1. Furthermore, in vitro kinase assay indicated that the kinase activities of R2 on CDKs and the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II were markedly elevated by binding to Os;CycH;1. Our results suggest that cyclin H is a regulatory subunit of CAK, which positively controls CDK- and CTD-kinase activities in plant cells.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {The Plant Journal},
	author = {Yamaguchi, Masatoshi and Fabian, Tanja and Sauter, Margret and Bhalerao, Rishikesh P. and Schrader, Jarmo and Sandberg, Göran and Umeda, Masaaki and Uchimiya, Hirofumi},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2000.00846.x},
	keywords = {CDK-activating kinase, cell cycle, cyclin H, cyclin-dependent protein kinase, poplar, rice},
	pages = {11--20},
}

cDNAs encoding cyclin H homologs were isolated from poplar (Populus tremulax tremuloides) and rice (Oryza sativa) plants, and were designated Pt;cycH;1 and Os;cycH;1, respectively. The deduced amino-acid sequences showed 40–60% similarity to human cyclin H and Schizosaccharomyces pombe Mcs2, with higher similarity in the cyclin box region. While Pt;cycH;1 and Os;cycH;1 were expressed in all tissues examined, the transcripts accumulated abundantly in dividing cells. Expression of Os;cycH;1 was abundant in the S-phase in partially synchronized suspension cells, and was induced by submergence in internodes of deepwater rice. A yeast two-hybrid assay demonstrated that both Pt;CycH;1 and Os;CycH;1 were able to interact with rice R2 kinase, which is structurally and functionally similar to cyclin-dependent kinase (CDK)-activating kinase (CAK) of vertebrates. Moreover, an in vitro pull-down assay showed that Os;CycH;1 specifically bound to R2 but not to other rice CDKs. When R2 was expressed in budding yeast CAK mutant, the suppression activity in terms of temperature-sensitivity was enhanced by co-expression with Os;cycH;1. Furthermore, in vitro kinase assay indicated that the kinase activities of R2 on CDKs and the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II were markedly elevated by binding to Os;CycH;1. Our results suggest that cyclin H is a regulatory subunit of CAK, which positively controls CDK- and CTD-kinase activities in plant cells.

@article{meszaros_multiple_2000,
	title = {Multiple cyclin-dependent kinase complexes and phosphatases control {G2}/{M} progression in alfalfa cells},
	volume = {43},
	issn = {1573-5028},
	url = {https://doi.org/10.1023/A:1006412413671},
	doi = {10/cb64mn},
	abstract = {Reversible phosphorylation of proteins by kinases and phosphatases plays a key regulatory role in several eukaryotic cellular functions including the control of the division cycle. Increasing numbers of sequence and biochemical data show the involvement of cyclin-dependent kinases (CDKs) and cyclins in regulation of the cell cycle progression in higher plants. The complexity represented by different types of CDKs and cyclins in a single species such as alfalfa, indicates that multicomponent regulatory pathways control G2/M transition. A set of cdc2-related genes (cdc2Ms A, B, D and F) was expressed in G2 and M cells. Phosphorylation assays also revealed that at least three kinase complexes (Cdc2Ms A/B, D and F) were successively active in G2/M cells after synchronization. Interaction between alfalfa mitotic cyclin (Medsa;CycB2;1) and a kinase partner has been reported previously. The present yeast two-hybrid analyses showed differential interaction between defined D-type cyclins and Cdc2Ms kinases functioning in G2/M phases. Localization of Cdc2Ms F kinase to the preprophase band (PPB), the perinuclear ring in early prophase, the mitotic spindle and the phragmoplast indicated a pivotal role for this kinase in mitotic plant cells. So far limited research efforts have been devoted to the functions of phosphatases in the control of plant cell division. A homologue of dual phosphatase, cdc25, has not been cloned yet from alfalfa; however tyrosine phosphorylation was indicated in the case of Cdc2Ms A kinase and the p13suc1-bound kinase activity was increased by treatment of this complex with recombinant Drosophila Cdc25. The potential role of serine/threonine phosphatases can be concluded from inhibitor studies based on okadaic acid or endothall. Endothall elevated the kinase activity of p13suc1-bound fractions in G2-phase alfalfa cells. These biochemical data are in accordance with observed cytological abnormalities. The present overview with selected original data outlines a conclusion that emphasizes the complexity of G2/M regulatory events in flowering plants.},
	language = {en},
	number = {5},
	urldate = {2021-11-08},
	journal = {Plant Molecular Biology},
	author = {Mészáros, Tamás and Miskolczi, Pál and Ayaydin, Ferhan and Pettkó-Szandtner, Aladár and Peres, Adrian and Magyar, Zoltán and Horváth, Gábor V. and Bakó, László and Fehér, Attila and Dudits, Dénes},
	month = aug,
	year = {2000},
	pages = {595--605},
}

Reversible phosphorylation of proteins by kinases and phosphatases plays a key regulatory role in several eukaryotic cellular functions including the control of the division cycle. Increasing numbers of sequence and biochemical data show the involvement of cyclin-dependent kinases (CDKs) and cyclins in regulation of the cell cycle progression in higher plants. The complexity represented by different types of CDKs and cyclins in a single species such as alfalfa, indicates that multicomponent regulatory pathways control G2/M transition. A set of cdc2-related genes (cdc2Ms A, B, D and F) was expressed in G2 and M cells. Phosphorylation assays also revealed that at least three kinase complexes (Cdc2Ms A/B, D and F) were successively active in G2/M cells after synchronization. Interaction between alfalfa mitotic cyclin (Medsa;CycB2;1) and a kinase partner has been reported previously. The present yeast two-hybrid analyses showed differential interaction between defined D-type cyclins and Cdc2Ms kinases functioning in G2/M phases. Localization of Cdc2Ms F kinase to the preprophase band (PPB), the perinuclear ring in early prophase, the mitotic spindle and the phragmoplast indicated a pivotal role for this kinase in mitotic plant cells. So far limited research efforts have been devoted to the functions of phosphatases in the control of plant cell division. A homologue of dual phosphatase, cdc25, has not been cloned yet from alfalfa; however tyrosine phosphorylation was indicated in the case of Cdc2Ms A kinase and the p13suc1-bound kinase activity was increased by treatment of this complex with recombinant Drosophila Cdc25. The potential role of serine/threonine phosphatases can be concluded from inhibitor studies based on okadaic acid or endothall. Endothall elevated the kinase activity of p13suc1-bound fractions in G2-phase alfalfa cells. These biochemical data are in accordance with observed cytological abnormalities. The present overview with selected original data outlines a conclusion that emphasizes the complexity of G2/M regulatory events in flowering plants.

@article{palmqvist_light_2000,
	title = {Light use efficiency of dry matter gain in five macro-lichens: relative impact of microclimate conditions and species-specific traits},
	volume = {23},
	issn = {1365-3040},
	shorttitle = {Light use efficiency of dry matter gain in five macro-lichens},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-3040.2000.00529.x},
	doi = {10/dhsfbp},
	abstract = {Relations between irradiance (I) and lichen growth were investigated for five macro-lichens growing at two sites in Sweden. The lichens represented different mycobiont–photobiont associations, two morphologies (foliose, fruticose) and two life forms (epiphytic, terricolous). The lichens were transplanted at two geographically distant sites in Sweden (1000 km apart) from Sept 1995 to Sept 1996 in their typical microhabitats, where microclimate and growth were followed. Between April/May and Sept 96, the terricolous species had a dry matter gain of 0·2 to 0·4 g (g DW)–1 and the epiphytes 0·01 to 0·02 g (g DW)–1. When related to area, growth amounted to 30 to 70 g m−2 for the terricolous species and to 1 to 4 g m−2 for the epiphytes. There was a strong correlation between growth and intercepted irradiance when the lichens were wet (Iwet), with 0·2 to 1·1 g lichen dry matter being produced per MJ solar energy. Across the 10 sets of transplants, light use efficiencies of dry matter yield (e) ranged between 0·5 and 2\%, using an energy equivalent of 17·5 kJ g−1 of lichen dry matter. The higher productivity of the terricolous species was due to longer periods with thallus water contents sufficient for metabolic activity and because of the higher mean photon flux densities of their microhabitat. A four-fold difference in photosynthetic capacity among the species was also important. It is concluded that lichen dry matter gain was primarily related to net carbon gain during metabolically active periods, which was determined by light duration, photon flux density and photosynthetic capacity.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {Plant, Cell \& Environment},
	author = {Palmqvist, K. and Sundberg, B.},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-3040.2000.00529.x},
	keywords = {chlorophyll, energy conversion efficiency, growth, irradiance, lichen, microclimate, photosynthesis, respiration},
	pages = {1--14},
}

Relations between irradiance (I) and lichen growth were investigated for five macro-lichens growing at two sites in Sweden. The lichens represented different mycobiont–photobiont associations, two morphologies (foliose, fruticose) and two life forms (epiphytic, terricolous). The lichens were transplanted at two geographically distant sites in Sweden (1000 km apart) from Sept 1995 to Sept 1996 in their typical microhabitats, where microclimate and growth were followed. Between April/May and Sept 96, the terricolous species had a dry matter gain of 0·2 to 0·4 g (g DW)–1 and the epiphytes 0·01 to 0·02 g (g DW)–1. When related to area, growth amounted to 30 to 70 g m−2 for the terricolous species and to 1 to 4 g m−2 for the epiphytes. There was a strong correlation between growth and intercepted irradiance when the lichens were wet (Iwet), with 0·2 to 1·1 g lichen dry matter being produced per MJ solar energy. Across the 10 sets of transplants, light use efficiencies of dry matter yield (e) ranged between 0·5 and 2%, using an energy equivalent of 17·5 kJ g−1 of lichen dry matter. The higher productivity of the terricolous species was due to longer periods with thallus water contents sufficient for metabolic activity and because of the higher mean photon flux densities of their microhabitat. A four-fold difference in photosynthetic capacity among the species was also important. It is concluded that lichen dry matter gain was primarily related to net carbon gain during metabolically active periods, which was determined by light duration, photon flux density and photosynthetic capacity.

@article{t_nucleotide_2000,
	title = {Nucleotide sequence of the {ADP}-glucose pyrophosphorylase promoter of barley ({Hordeum} vulgare {L}.), a gene involved in endosperm starch formation.},
	volume = {122},
	journal = {Plant physiology},
	author = {T, Thorbjørnsen and P, Villand and VE, Ramstad and Kleczkowski, Leszek and O-A, Olsen and HG, Opsahl-Ferstad},
	month = jan,
	year = {2000},
	keywords = {⛔ No DOI found},
	pages = {1457 (Plant Gene Register)},
}

@article{funk_functional_2000,
	title = {Functional analysis of the {PsbX} protein by deletion of the corresponding gene in {Synechocystis} sp. {PCC} 6803},
	volume = {44},
	issn = {1573-5028},
	url = {https://doi.org/10.1023/A:1026764728846},
	doi = {10/b24gh6},
	abstract = {The psbX gene (sml0002) coding for a 4.1 kDa protein in Photosystem II of plants and cyanobacteria was deleted in both wild type and in a Photosystem I-less mutant of the cyanobacterium Synechocystis sp. PCC 6803. Polymerase chain reaction and sequencing analysis showed that the mutants had completely segregated. Deletion of the PsbX protein does not seem to influence growth rate, electron transport or water oxidation ability. Whereas a high light induction of the psbX mRNA could be observed in wild type, deletion of the gene did not lead to high light sensibility. Light saturation measurements and 77K fluorescence measurements indicated a minor disconnection of the antenna in the deletion mutant. Furthermore, fluorescence induction measurements as well as immuno-staining of the D1 protein showed that the amount of Photosystem II complexes in the mutants was reduced by 30\%. Therefore, PsbX does not seem to be necessary for the Photosystem II electron transport, but directly or indirectly involved in the regulation of the amount of functionally active Photosystem II centres in Synechocystis sp. PCC 6803.},
	language = {en},
	number = {6},
	urldate = {2021-11-08},
	journal = {Plant Molecular Biology},
	author = {Funk, Christiane},
	month = dec,
	year = {2000},
	pages = {815--827},
}

The psbX gene (sml0002) coding for a 4.1 kDa protein in Photosystem II of plants and cyanobacteria was deleted in both wild type and in a Photosystem I-less mutant of the cyanobacterium Synechocystis sp. PCC 6803. Polymerase chain reaction and sequencing analysis showed that the mutants had completely segregated. Deletion of the PsbX protein does not seem to influence growth rate, electron transport or water oxidation ability. Whereas a high light induction of the psbX mRNA could be observed in wild type, deletion of the gene did not lead to high light sensibility. Light saturation measurements and 77K fluorescence measurements indicated a minor disconnection of the antenna in the deletion mutant. Furthermore, fluorescence induction measurements as well as immuno-staining of the D1 protein showed that the amount of Photosystem II complexes in the mutants was reduced by 30%. Therefore, PsbX does not seem to be necessary for the Photosystem II electron transport, but directly or indirectly involved in the regulation of the amount of functionally active Photosystem II centres in Synechocystis sp. PCC 6803.

@article{eklof_transgenic_2000,
	title = {Transgenic tobacco plants co-expressing {Agrobacterium} iaa and ipt genes have wild-type hormone levels but display both auxin- and cytokinin-overproducing phenotypes},
	volume = {23},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2000.00762.x},
	doi = {10/dkzdj3},
	abstract = {Transgenic tobacco lines simultaneously expressing the Agrobacterium iaaM, iaaH and ipt genes, obtained by crossing lines expressing ipt with lines expressing iaaM and iaaH, were used to study in planta interactions between auxin and cytokinins. All phenotypic traits of the respective parental lines characteristic of cytokinin and auxin overproduction were present in the cross. Indole-3-acetic acid (IAA) and combined zeatin riboside (ZR) and zeatin riboside-5′-monophosphate (ZRMP) contents were analysed by mass spectrometry in young, developing leaves from the cross, the parental lines and the wild type. Unexpectedly, hormone levels in the cross were very similar to wild-type levels. Thus IAA levels in the cross were much lower throughout vegetative development than in the parental IAA overproducing line, although expression of the bacterial IAA biosynthesis genes was not reduced. The results suggest that effects on apical dominance, adventitious root formation, leaf morphology and other traits commonly ± associated with IAA and cytokinin overproduction, and observed in the iaaËipt cross, cannot be explained solely by analysis of auxin and cytokinin contents in individual organs. As traits associated with both hormones are expressed in close spatial and temporal proximity, it is likely that cellular resolution of hormone contents is essential to explain physiological responses to auxins and cytokinins.},
	language = {en},
	number = {2},
	urldate = {2021-11-08},
	journal = {The Plant Journal},
	author = {Eklöf, Staffan and Åstot, Crister and Sitbon, Folke and Moritz, Thomas and Olsson, Olof and Sandberg, Göran},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2000.00762.x},
	keywords = {IAA, Nicotiana tabacum, cytokinin, morphology, ratio hypothesis, transgenic plants},
	pages = {279--284},
}

Transgenic tobacco lines simultaneously expressing the Agrobacterium iaaM, iaaH and ipt genes, obtained by crossing lines expressing ipt with lines expressing iaaM and iaaH, were used to study in planta interactions between auxin and cytokinins. All phenotypic traits of the respective parental lines characteristic of cytokinin and auxin overproduction were present in the cross. Indole-3-acetic acid (IAA) and combined zeatin riboside (ZR) and zeatin riboside-5′-monophosphate (ZRMP) contents were analysed by mass spectrometry in young, developing leaves from the cross, the parental lines and the wild type. Unexpectedly, hormone levels in the cross were very similar to wild-type levels. Thus IAA levels in the cross were much lower throughout vegetative development than in the parental IAA overproducing line, although expression of the bacterial IAA biosynthesis genes was not reduced. The results suggest that effects on apical dominance, adventitious root formation, leaf morphology and other traits commonly ± associated with IAA and cytokinin overproduction, and observed in the iaaËipt cross, cannot be explained solely by analysis of auxin and cytokinin contents in individual organs. As traits associated with both hormones are expressed in close spatial and temporal proximity, it is likely that cellular resolution of hormone contents is essential to explain physiological responses to auxins and cytokinins.

@article{barlier_sur2_2000,
	title = {The {SUR2} gene of {Arabidopsis} thaliana encodes the cytochrome {P450} {CYP83B1}, a modulator of auxin homeostasis},
	volume = {97},
	copyright = {Copyright © 2000, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/97/26/14819},
	doi = {10/c36wb6},
	abstract = {Genetic screens have been performed to identify mutants with altered auxin homeostasis in Arabidopsis. A tagged allele of the auxin-overproducing mutant sur2 was identified within a transposon mutagenized population. The SUR2 gene was cloned and shown to encode the CYP83B1 protein, which belongs to the large family of the P450-dependent monooxygenases. SUR2 expression is up-regulated in sur1 mutants and induced by exogenous auxin in the wild type. Analysis of indole-3-acetic acid (IAA) synthesis and metabolism in sur2 plants indicates that the mutation causes a conditional increase in the pool size of IAA through up-regulation of IAA synthesis.},
	language = {en},
	number = {26},
	urldate = {2021-11-08},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Barlier, Isabelle and Kowalczyk, Mariusz and Marchant, Alan and Ljung, Karin and Bhalerao, Rishikesh and Bennett, Malcolm and Sandberg, Goeran and Bellini, Catherine},
	month = dec,
	year = {2000},
	pmid = {11114200},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	keywords = {metabolism},
	pages = {14819--14824},
}

Genetic screens have been performed to identify mutants with altered auxin homeostasis in Arabidopsis. A tagged allele of the auxin-overproducing mutant sur2 was identified within a transposon mutagenized population. The SUR2 gene was cloned and shown to encode the CYP83B1 protein, which belongs to the large family of the P450-dependent monooxygenases. SUR2 expression is up-regulated in sur1 mutants and induced by exogenous auxin in the wild type. Analysis of indole-3-acetic acid (IAA) synthesis and metabolism in sur2 plants indicates that the mutation causes a conditional increase in the pool size of IAA through up-regulation of IAA synthesis.

@article{fagard_ago1_2000,
	title = {{AGO1}, {QDE}-2, and {RDE}-1 are related proteins required for post-transcriptional gene silencing in plants, quelling in fungi, and {RNA} interference in animals},
	volume = {97},
	copyright = {Copyright © 2000, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/97/21/11650},
	doi = {10/dbx439},
	abstract = {Introduction of transgene DNA may lead to specific degradation of RNAs that are homologous to the transgene transcribed sequence through phenomena named post-transcriptional gene silencing (PTGS) in plants, quelling in fungi, and RNA interference (RNAi) in animals. It was shown previously that PTGS, quelling, and RNAi require a set of related proteins (SGS2, QDE-1, and EGO-1, respectively). Here we report the isolation of Arabidopsis mutants impaired in PTGS which are affected at the Argonaute1 (AGO1) locus. AGO1 is similar to QDE-2 required for quelling and RDE-1 required for RNAi. Sequencing of ago1 mutants revealed one amino acid essential for PTGS that is also present in QDE-2 and RDE-1 in a highly conserved motif. Taken together, these results confirm the hypothesis that these processes derive from a common ancestral mechanism that controls expression of invading nucleic acid molecules at the post-transcriptional level. As opposed to rde-1 and qde-2 mutants, which are viable, ago1 mutants display several developmental abnormalities, including sterility. These results raise the possibility that PTGS, or at least some of its elements, could participate in the regulation of gene expression during development in plants.},
	language = {en},
	number = {21},
	urldate = {2021-11-08},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Fagard, Mathilde and Boutet, Stéphanie and Morel, Jean-Benoit and Bellini, Catherine and Vaucheret, Hervé},
	month = oct,
	year = {2000},
	pmid = {11016954},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	pages = {11650--11654},
}

Introduction of transgene DNA may lead to specific degradation of RNAs that are homologous to the transgene transcribed sequence through phenomena named post-transcriptional gene silencing (PTGS) in plants, quelling in fungi, and RNA interference (RNAi) in animals. It was shown previously that PTGS, quelling, and RNAi require a set of related proteins (SGS2, QDE-1, and EGO-1, respectively). Here we report the isolation of Arabidopsis mutants impaired in PTGS which are affected at the Argonaute1 (AGO1) locus. AGO1 is similar to QDE-2 required for quelling and RDE-1 required for RNAi. Sequencing of ago1 mutants revealed one amino acid essential for PTGS that is also present in QDE-2 and RDE-1 in a highly conserved motif. Taken together, these results confirm the hypothesis that these processes derive from a common ancestral mechanism that controls expression of invading nucleic acid molecules at the post-transcriptional level. As opposed to rde-1 and qde-2 mutants, which are viable, ago1 mutants display several developmental abnormalities, including sterility. These results raise the possibility that PTGS, or at least some of its elements, could participate in the regulation of gene expression during development in plants.

@article{igamberdiev_capacity_2000,
	title = {Capacity for {NADPH}/{NADP} turnover in the cytosol of barley seed endosperm: {The} role of {NADPH}-dependent hydroxypyruvate reductase},
	volume = {38},
	issn = {0981-9428},
	shorttitle = {Capacity for {NADPH}/{NADP} turnover in the cytosol of barley seed endosperm},
	url = {https://www.sciencedirect.com/science/article/pii/S0981942800011876},
	doi = {10/dps4mx},
	abstract = {Barley (Hordeum vulgare L.) endosperm from developing seeds was found to contain relatively high activities of cytosolic NAD(P)H-dependent hydroxypyruvate reductase (HPR-2) and isocitrate dehydrogenase (ICDH). In contrast, activities of peroxisomal NADH-dependent hydroxypyruvate reductase (HPR-1) and glycolate oxidase as well as cytosolic NAD(P)H-dependent glyoxylate reductase were very low or absent in the endosperm both during maturation and seed germination, indicating the lack of a complete glycolate cycle in this tissue. In addition, activities of cytosolic glucose-6-phosphate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase were low or absent in the endosperm. The endosperm HPR-2 exhibited similar properties to those of an earlier described HPR-2 from green leaves, e.g. activities with both hydroxypyruvate and glyoxylate, utilization of both NADPH and NADH as cofactors, and a strong uncompetitive inhibition by oxalate (Ki in the order of micromolar). In etiolated leaves, both HPR-1 and HPR-2 were present with the same activity as in green leaves, indicating that the lack of HPR-1 in the endosperm is not a general feature of non-photosynthetic tissues. We conclude that the endosperm has considerable capacity for cytosolic NADP/NADPH cycling via HPR-2 and ICDH, the former being possibly involved in the utilization of a serine-derived carbon.},
	language = {en},
	number = {10},
	urldate = {2021-11-08},
	journal = {Plant Physiology and Biochemistry},
	author = {Igamberdiev, Abir U. and Kleczkowski, Leszek A.},
	month = oct,
	year = {2000},
	keywords = {cytosol, glyoxylate, hydroxypyruvate reductase, seed germination, starch synthesis, sucrose synthesis},
	pages = {747--753},
}

Barley (Hordeum vulgare L.) endosperm from developing seeds was found to contain relatively high activities of cytosolic NAD(P)H-dependent hydroxypyruvate reductase (HPR-2) and isocitrate dehydrogenase (ICDH). In contrast, activities of peroxisomal NADH-dependent hydroxypyruvate reductase (HPR-1) and glycolate oxidase as well as cytosolic NAD(P)H-dependent glyoxylate reductase were very low or absent in the endosperm both during maturation and seed germination, indicating the lack of a complete glycolate cycle in this tissue. In addition, activities of cytosolic glucose-6-phosphate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase were low or absent in the endosperm. The endosperm HPR-2 exhibited similar properties to those of an earlier described HPR-2 from green leaves, e.g. activities with both hydroxypyruvate and glyoxylate, utilization of both NADPH and NADH as cofactors, and a strong uncompetitive inhibition by oxalate (Ki in the order of micromolar). In etiolated leaves, both HPR-1 and HPR-2 were present with the same activity as in green leaves, indicating that the lack of HPR-1 in the endosperm is not a general feature of non-photosynthetic tissues. We conclude that the endosperm has considerable capacity for cytosolic NADP/NADPH cycling via HPR-2 and ICDH, the former being possibly involved in the utilization of a serine-derived carbon.

@article{micheli_radial_2000,
	title = {Radial {Distribution} {Pattern} of {Pectin} {Methylesterases} across the {Cambial} {Region} of {Hybrid} {Aspen} at {Activity} and {Dormancy1}},
	volume = {124},
	issn = {0032-0889},
	url = {https://doi.org/10.1104/pp.124.1.191},
	doi = {10/dfr3jq},
	abstract = {Biochemical microanalysis combined with tangential cryosectioning was used to visualize the distribution of pectin methylesterases (PMEs) across the cambial region in active and dormant hybrid aspen (Populus tremula L. × Populus tremuloides Michx). These novel techniques allowed us to relate activity and isoforms of PMEs to specific tissues and developmental stages of the stem to get more information on the physiological function of PMEs in cambial growth. Isoelectrofocusing analysis revealed numerous isoforms that were differentially distributed according to the tissue-type and to the cambial stage. A neutral isoform was found to be distributed ubiquitously across the stem of both active and dormant trees, which suggests that it is a housekeeping isoform involved in the maintenance of the cell wall integrity throughout the stem. In addition, two distinct isoforms having different isoelectric points were found to be related to the differentiation of cambial derivatives. A basic isoform appears to be a physiological marker of the dormant stage involved in the cessation of meristematic radial growth, whereas an acidic isoform is functionally related to the immediate expansion of the cambial daughter cells that occurs bilaterally on each side of the cambium at the active stage.},
	number = {1},
	urldate = {2021-11-08},
	journal = {Plant Physiology},
	author = {Micheli, Fabienne and Sundberg, Björn and Goldberg, Renée and Richard, Luc},
	month = sep,
	year = {2000},
	pages = {191--200},
}

Biochemical microanalysis combined with tangential cryosectioning was used to visualize the distribution of pectin methylesterases (PMEs) across the cambial region in active and dormant hybrid aspen (Populus tremula L. × Populus tremuloides Michx). These novel techniques allowed us to relate activity and isoforms of PMEs to specific tissues and developmental stages of the stem to get more information on the physiological function of PMEs in cambial growth. Isoelectrofocusing analysis revealed numerous isoforms that were differentially distributed according to the tissue-type and to the cambial stage. A neutral isoform was found to be distributed ubiquitously across the stem of both active and dormant trees, which suggests that it is a housekeeping isoform involved in the maintenance of the cell wall integrity throughout the stem. In addition, two distinct isoforms having different isoelectric points were found to be related to the differentiation of cambial derivatives. A basic isoform appears to be a physiological marker of the dormant stage involved in the cessation of meristematic radial growth, whereas an acidic isoform is functionally related to the immediate expansion of the cambial daughter cells that occurs bilaterally on each side of the cambium at the active stage.

@article{ingvarsson_heterosis_2000,
	title = {Heterosis increases the effective migration rate},
	volume = {267},
	url = {https://royalsocietypublishing.org/doi/10.1098/rspb.2000.1145},
	doi = {10/ct4pr6},
	abstract = {Individuals coming from the same subpopulation are more likely to share deleterious mutations at any given locus than hybrids formed between parents from different populations. Offspring of migrants therefore may experience heterosis and have higher fitness than resident individuals. This will, in turn, result in the immigrant alleles being present in higher frequencies than predicted from neutral expectations and thus a higher effective migration rate. In this paper we derive a formula to calculate the effective migration rate in the presence of heterosis. It is shown that the effect of heterosis on the migration rate can be substantial when fitness reduction within local populations is severe. The effect will be more pronounced in species with relatively short map lengths. Furthermore the heterosis effect will be highly variable throughout the genome, with the largest effect seen near selected genes and in regions of high gene density.},
	number = {1450},
	urldate = {2021-11-08},
	journal = {Proceedings of the Royal Society of London. Series B: Biological Sciences},
	author = {Ingvarsson, Pär K. and Whitlock, Michael C.},
	month = jul,
	year = {2000},
	note = {Publisher: Royal Society},
	keywords = {Drift Load, Gene Flow, Heterosis, Migration, Population Structure, Recombination},
	pages = {1321--1326},
}

Individuals coming from the same subpopulation are more likely to share deleterious mutations at any given locus than hybrids formed between parents from different populations. Offspring of migrants therefore may experience heterosis and have higher fitness than resident individuals. This will, in turn, result in the immigrant alleles being present in higher frequencies than predicted from neutral expectations and thus a higher effective migration rate. In this paper we derive a formula to calculate the effective migration rate in the presence of heterosis. It is shown that the effect of heterosis on the migration rate can be substantial when fitness reduction within local populations is severe. The effect will be more pronounced in species with relatively short map lengths. Furthermore the heterosis effect will be highly variable throughout the genome, with the largest effect seen near selected genes and in regions of high gene density.

@article{astot_alternative_2000,
	title = {An alternative cytokinin biosynthesis pathway},
	volume = {97},
	copyright = {Copyright © 2000, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/97/26/14778},
	doi = {10/dt77jp},
	abstract = {Studies of de novo cytokinin biosynthesis in isopentenyltransferase (ipt)-transformed Arabidopsis thaliana, involving in vivo deuterium labeling and mass spectrometry, showed that the biosynthetic rate of zeatinriboside-5′-monophosphate was around 66-fold higher than that of isopentenyladenosine-5′-monophosphate (iPMP), the proposed primary product of the Agrobacterium ipt. Double tracer analysis, using [2H6] isopentenyladenosine and deuterium oxide, provided evidence for an alternative, iPMP-independent, biosynthetic pathway for zeatin-type cytokinins, present in both ipt-expressing and wild-type Arabidopsis thaliana. Reduction of the biosynthetic flux in the alternative pathway by use of mevastatin, an inhibitor for 3-hydroxy-3-methylglutaryl CoA reductase, indicated a terpenoid origin for the side-chain precursor of the iPMP independent pathway.},
	language = {en},
	number = {26},
	urldate = {2021-11-08},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Åstot, Crister and Dolezal, Karel and Nordström, Anders and Wang, Qun and Kunkel, Tim and Moritz, Thomas and Chua, Nam-Hai and Sandberg, Göran},
	month = dec,
	year = {2000},
	pmid = {11114204},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	pages = {14778--14783},
}

Studies of de novo cytokinin biosynthesis in isopentenyltransferase (ipt)-transformed Arabidopsis thaliana, involving in vivo deuterium labeling and mass spectrometry, showed that the biosynthetic rate of zeatinriboside-5′-monophosphate was around 66-fold higher than that of isopentenyladenosine-5′-monophosphate (iPMP), the proposed primary product of the Agrobacterium ipt. Double tracer analysis, using [2H6] isopentenyladenosine and deuterium oxide, provided evidence for an alternative, iPMP-independent, biosynthetic pathway for zeatin-type cytokinins, present in both ipt-expressing and wild-type Arabidopsis thaliana. Reduction of the biosynthetic flux in the alternative pathway by use of mevastatin, an inhibitor for 3-hydroxy-3-methylglutaryl CoA reductase, indicated a terpenoid origin for the side-chain precursor of the iPMP independent pathway.

@article{sitbon_relative_2000,
	title = {The relative importance of tryptophan-dependent and tryptophan-independent biosynthesis of indole-3-acetic acid in tobacco during vegetative growth},
	volume = {211},
	issn = {1432-2048},
	url = {https://doi.org/10.1007/s004250000338},
	doi = {10/bxcbw8},
	abstract = {A quantitative study of indole-3-acetic acid (IAA) turnover, and the contribution of tryptophan-dependent and tryptophan-independent IAA-biosynthesis pathways, was carried out using protoplast preparations and shoot apices obtained from wild-type and transgenic, IAA-overproducing tobacco (Nicotiana tabacum L.) plants, during a phase of growth when the level of endogenous IAA was stable. Based on the rate of disappearance of [13C6]IAA, the half-life of the IAA pool was calculated to be 1.1 h in wild-type protoplasts and 0.8 h in protoplasts from the IAA-overproducing line, corresponding to metabolic rates of 59 and 160 pg IAA (μg Chl)−1 h−1, respectively. The rate of conversion of tryptophan to IAA was 15 pg IAA (μg Chl)−1 h−1 in wild-type protoplasts and 101 pg IAA (μg Chl)−1 h−1 in protoplasts from IAA-overproducing plants. In both instances, IAA was metabolised more rapidly than it was synthesised from tryptophan. As the endogenous IAA pools were in a steady state, these findings indicate that IAA biosynthesis via the tryptophan-independent pathway was 44 pg IAA (μg Chl)−1 h−1 and 59 pg IAA (μg Chl)−1 h−1, respectively, in the wild-type and transformed protoplast preparations. In a parallel study with apical shoot tissue, the presumed site of IAA biosynthesis, the rate of tryptophan-dependent IAA biosynthesis exceeded the rate of metabolism of [13C6]IAA despite the steady state of the endogenous IAA pool. The most likely explanation for this anomaly is that, unlike the protoplast system, injection of substrates into the apical tissues did not result in uniform distribution of label, and that at least some of the [2H5]tryptophan was metabolised in compartments not normally active in IAA biosynthesis. This demonstrates the importance of using experimental systems where labelling of the precursor pool can be strictly controlled.},
	language = {en},
	number = {5},
	urldate = {2021-11-08},
	journal = {Planta},
	author = {Sitbon, Folke and Åstot, Crister and Edlund, Agneta and Crozier, Alan and Sandberg, Göran},
	month = oct,
	year = {2000},
	pages = {715--721},
}

A quantitative study of indole-3-acetic acid (IAA) turnover, and the contribution of tryptophan-dependent and tryptophan-independent IAA-biosynthesis pathways, was carried out using protoplast preparations and shoot apices obtained from wild-type and transgenic, IAA-overproducing tobacco (Nicotiana tabacum L.) plants, during a phase of growth when the level of endogenous IAA was stable. Based on the rate of disappearance of [13C6]IAA, the half-life of the IAA pool was calculated to be 1.1 h in wild-type protoplasts and 0.8 h in protoplasts from the IAA-overproducing line, corresponding to metabolic rates of 59 and 160 pg IAA (μg Chl)−1 h−1, respectively. The rate of conversion of tryptophan to IAA was 15 pg IAA (μg Chl)−1 h−1 in wild-type protoplasts and 101 pg IAA (μg Chl)−1 h−1 in protoplasts from IAA-overproducing plants. In both instances, IAA was metabolised more rapidly than it was synthesised from tryptophan. As the endogenous IAA pools were in a steady state, these findings indicate that IAA biosynthesis via the tryptophan-independent pathway was 44 pg IAA (μg Chl)−1 h−1 and 59 pg IAA (μg Chl)−1 h−1, respectively, in the wild-type and transformed protoplast preparations. In a parallel study with apical shoot tissue, the presumed site of IAA biosynthesis, the rate of tryptophan-dependent IAA biosynthesis exceeded the rate of metabolism of [13C6]IAA despite the steady state of the endogenous IAA pool. The most likely explanation for this anomaly is that, unlike the protoplast system, injection of substrates into the apical tissues did not result in uniform distribution of label, and that at least some of the [2H5]tryptophan was metabolised in compartments not normally active in IAA biosynthesis. This demonstrates the importance of using experimental systems where labelling of the precursor pool can be strictly controlled.

@article{villegas_effects_2000,
	title = {Effects of sodium orthovanadate on benzophenanthridine alkaloid formation and distribution in cell suspension cultures of {Eschscholtzia} californica},
	volume = {38},
	issn = {0981-9428},
	url = {https://www.sciencedirect.com/science/article/pii/S0981942800007361},
	doi = {10/bg7m4h},
	abstract = {Cell suspension cultures of Eschscholtzia californica produce relatively large amounts of benzophenanthridine alkaloids upon elicitation. Sodium orthovanadate is used as an abiotic elicitor to induce alkaloid biosynthesis in cultures of E. californica. The response of the cell culture to this abiotic elicitor is very similar to that observed after elicitation with a biotic elicitor (a carbohydrate fraction from yeast extract). Treatment with orthovanadate leads to alkalinization of the growth medium, a 20-fold induction of the key enzyme tyrosine decarboxylase and increased alkaloid formation (up to 40 mg.L–1). Cells treated with the yeast elicitor excrete a large portion of alkaloids produced into the growth medium (up to 50 \% of total alkaloids) while cells treated with orthovanadate release very small amounts of alkaloids into the medium (less than 10 \% of total alkaloids). These results suggest that an active transport system, possibly specific for benzophenanthridine alkaloids, is present in the plasma membrane of E. californica cells. The nature of this putative vanadate-sensitive transporter is not known at present.},
	language = {en},
	number = {3},
	urldate = {2021-11-08},
	journal = {Plant Physiology and Biochemistry},
	author = {Villegas, Mirza and Sommarin, Marianne and Brodelius, Peter E},
	month = mar,
	year = {2000},
	keywords = {Benzophenanthridine alkaloids, elicitation, orthovanadate, plasma membrane ATPase, proton pumping, tyrosine decarboxylase},
	pages = {233--241},
}

Cell suspension cultures of Eschscholtzia californica produce relatively large amounts of benzophenanthridine alkaloids upon elicitation. Sodium orthovanadate is used as an abiotic elicitor to induce alkaloid biosynthesis in cultures of E. californica. The response of the cell culture to this abiotic elicitor is very similar to that observed after elicitation with a biotic elicitor (a carbohydrate fraction from yeast extract). Treatment with orthovanadate leads to alkalinization of the growth medium, a 20-fold induction of the key enzyme tyrosine decarboxylase and increased alkaloid formation (up to 40 mg.L–1). Cells treated with the yeast elicitor excrete a large portion of alkaloids produced into the growth medium (up to 50 % of total alkaloids) while cells treated with orthovanadate release very small amounts of alkaloids into the medium (less than 10 % of total alkaloids). These results suggest that an active transport system, possibly specific for benzophenanthridine alkaloids, is present in the plasma membrane of E. californica cells. The nature of this putative vanadate-sensitive transporter is not known at present.

@article{garcia_qtl_2000,
	title = {{QTL} analysis of yield and seed number in {Citrus}},
	volume = {101},
	issn = {1432-2242},
	url = {https://doi.org/10.1007/s001220051507},
	doi = {10/fgq26k},
	abstract = {Amount, regularity and low seed content of the crop are important properties of scion citrus cultivars. The genetic control of these traits was studied in a progeny derived from the cross Citrus volkameriana×Poncirus trifoliata using molecular marker analysis. Since the traits were not normally distributed, the Kruskal-Wallis non-parametric test was used for quantitative trait loci (QTLs) detection. Most of the QTLs detected correspond to the trait ”number of fruits per tree”, in agreement with its known physiological complexity. Related traits (fruit number, fruit size and seed number) are controlled by QTLs some of which are located in the same genomic regions, suggesting that undesired associations could be broken to some degree by recombination. QTL analysis over years revealed important effects of genotype-by-environment interaction on QTL detection. This result agrees with the differences found for the trait means among years, which was found to be related, among other causes, to the alternate bearing of some genotypes and the amount of rain before harvest.},
	language = {en},
	number = {3},
	urldate = {2021-11-08},
	journal = {Theoretical and Applied Genetics},
	author = {García, M. R. and Asíns, M. J. and Carbonell, E. A.},
	month = aug,
	year = {2000},
	pages = {487--493},
}

Amount, regularity and low seed content of the crop are important properties of scion citrus cultivars. The genetic control of these traits was studied in a progeny derived from the cross Citrus volkameriana×Poncirus trifoliata using molecular marker analysis. Since the traits were not normally distributed, the Kruskal-Wallis non-parametric test was used for quantitative trait loci (QTLs) detection. Most of the QTLs detected correspond to the trait ”number of fruits per tree”, in agreement with its known physiological complexity. Related traits (fruit number, fruit size and seed number) are controlled by QTLs some of which are located in the same genomic regions, suggesting that undesired associations could be broken to some degree by recombination. QTL analysis over years revealed important effects of genotype-by-environment interaction on QTL detection. This result agrees with the differences found for the trait means among years, which was found to be related, among other causes, to the alternate bearing of some genotypes and the amount of rain before harvest.

@article{westin_phenotypic_2000,
	title = {Phenotypic {Differences} {Between} {Natural} and {Selected} {Populations} of {Picea} {Abies}. {II}. {Apical} {Mitotic} {Activity} and {Growth} {Related} {Parameters}},
	volume = {15},
	issn = {0282-7581},
	url = {https://doi.org/10.1080/028275800750173410},
	doi = {10/d82ffh},
	abstract = {Apical mitotic index (MI) and growth of non-juvenile Norway spruce [Picea abies (L.) Karst.] populations growing in northern Sweden (63°54' N) were monitored in 1996. Annual leader shoot lengths and shoot growth components for the period 1990-1997 were measured in 1997. In 1997 populations transferred more than approximately 3° in latitude were found to be shorter than local populations. MI levels were initially high in all populations in mid-April. In spring, populations originating north of 63°30' N showed higher MI levels, and started shoot growth earlier, than populations originating further south. In autumn, MI levels were higher in populations originating south of 63°30' N than in populations originating further north and higher in seed orchard populations than in natural populations of similar latitudinal origin. The number of stem-units (NSU) was correlated with tree height and leader shoot length. NSU and elongation of stem-units appeared to be primarily influenced by summer temperature. Prolonged MI activity in autumn did not result in high NSU but appeared to be associated with a higher risk of frost damage to buds. The results are discussed in relation to climatic factors, seed transfer, selection and inherent growth rhythms.},
	number = {5},
	urldate = {2021-11-08},
	journal = {Scandinavian Journal of Forest Research},
	author = {Westin, Johan and Sundblad, Lars-Göran and Strand, Martin and Hällgren, Jan-Erik},
	month = jan,
	year = {2000},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/028275800750173410},
	keywords = {Buds, Climate, Mitotic Activity, Rhythm, Selection, Shoot Growth, Stem Units, Transfer},
	pages = {500--509},
}

Apical mitotic index (MI) and growth of non-juvenile Norway spruce [Picea abies (L.) Karst.] populations growing in northern Sweden (63°54' N) were monitored in 1996. Annual leader shoot lengths and shoot growth components for the period 1990-1997 were measured in 1997. In 1997 populations transferred more than approximately 3° in latitude were found to be shorter than local populations. MI levels were initially high in all populations in mid-April. In spring, populations originating north of 63°30' N showed higher MI levels, and started shoot growth earlier, than populations originating further south. In autumn, MI levels were higher in populations originating south of 63°30' N than in populations originating further north and higher in seed orchard populations than in natural populations of similar latitudinal origin. The number of stem-units (NSU) was correlated with tree height and leader shoot length. NSU and elongation of stem-units appeared to be primarily influenced by summer temperature. Prolonged MI activity in autumn did not result in high NSU but appeared to be associated with a higher risk of frost damage to buds. The results are discussed in relation to climatic factors, seed transfer, selection and inherent growth rhythms.

@article{westin_phenotypic_2000,
	title = {Phenotypic {Differences} {Between} {Natural} and {Selected} {Populations} of {Picea} {Abies}. {I}. {Frost} {Hardiness}},
	volume = {15},
	issn = {0282-7581},
	url = {https://doi.org/10.1080/028275800750173393},
	doi = {10/bk8hkf},
	abstract = {The frost hardiness of non-juvenile Norway spruce [Picea abies (L.) Karst.] populations growing in northern Sweden (63°54' N) was monitored during 1996-1997. The investigated progenies originated from 12 natural populations and six seed orchards located between 58° N and 68° N in Sweden. Frost hardiness of needles was assessed by measuring chlorophyll fluorescence and electrolyte leakage after freezing. The loss of frost hardiness in 1-yr-old needles during spring occurred slightly earlier in populations originating north of 63°30' N than in those originating further south. Dehardening was slightly delayed in selected populations compared with natural populations of similar origin. The level of frost hardiness during autumn was higher in populations originating north of 63°30' N than in those originating south of this latitude, but there were no clear differences in frost hardiness between selected and natural populations of similar origin. The results are discussed in relation to climatic factors and inherent growth rhythms.},
	number = {5},
	urldate = {2021-11-08},
	journal = {Scandinavian Journal of Forest Research},
	author = {Westin, Johan and Sundblad, Lars-Göran and Strand, Martin and Hällgren, Jan-Erik},
	month = jan,
	year = {2000},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/028275800750173393},
	keywords = {Buds, Climate, Hardiness, Needles, Norway Spruce, Picea Abies, Rhythm, Selection},
	pages = {489--499},
}

The frost hardiness of non-juvenile Norway spruce [Picea abies (L.) Karst.] populations growing in northern Sweden (63°54' N) was monitored during 1996-1997. The investigated progenies originated from 12 natural populations and six seed orchards located between 58° N and 68° N in Sweden. Frost hardiness of needles was assessed by measuring chlorophyll fluorescence and electrolyte leakage after freezing. The loss of frost hardiness in 1-yr-old needles during spring occurred slightly earlier in populations originating north of 63°30' N than in those originating further south. Dehardening was slightly delayed in selected populations compared with natural populations of similar origin. The level of frost hardiness during autumn was higher in populations originating north of 63°30' N than in those originating south of this latitude, but there were no clear differences in frost hardiness between selected and natural populations of similar origin. The results are discussed in relation to climatic factors and inherent growth rhythms.

@article{tuominen_cambial-region-specific_2000,
	title = {Cambial-{Region}-{Specific} {Expression} of the {Agrobacterium} iaa {Genes} in {Transgenic} {Aspen} {Visualized} by a {Linked} {uidA} {Reporter} {Gene}},
	volume = {123},
	issn = {0032-0889},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC59021/},
	abstract = {The level of indole-3-acetic acid (IAA) was locally modified in cambial tissues of transgenic aspen (Populus tremula L. × Populus tremuloides Michx.). We also demonstrate the use of a linked reporter gene to visualize the expression of the iaa genes. The rate-limiting bacterial IAA-biosynthetic gene iaaM and the reporter gene for β-glucuronidase (GUS), uidA, were each fused to the cambial-region-specific Agrobacterium rhizogenes rolC promoter and linked on the same T-DNA. In situ hybridization of the iaaM gene confirmed that histochemical analysis of GUS activity could be used to predict iaaM gene expression. Moreover, quantitative fluorometric analysis of GUS activity allowed estimation of the level of de novo production of IAA in transgenic lines carrying a single-copy insert of the iaaM, uidA T-DNA. Microscale analysis of the IAA concentration across the cambial region tissues showed an increase in IAA concentration of about 35\% to 40\% in the two transgenic lines, but no changes in the radial distribution pattern of IAA compared with wild-type plants. This increase did not result in any changes in the developmental pattern of cambial derivatives or the cambial growth rate, which emphasizes the importance of the radial distribution pattern of IAA in controlling the development of secondary xylem, and suggests that a moderate increase in IAA concentration does not necessarily stimulate growth.},
	number = {2},
	urldate = {2021-11-08},
	journal = {Plant Physiology},
	author = {Tuominen, Hannele and Puech, Laurence and Regan, Sharon and Fink, Siegfried and Olsson, Olof and Sundberg, Björn},
	month = jun,
	year = {2000},
	pmid = {10859183},
	pmcid = {PMC59021},
	pages = {531--542},
}

The level of indole-3-acetic acid (IAA) was locally modified in cambial tissues of transgenic aspen (Populus tremula L. × Populus tremuloides Michx.). We also demonstrate the use of a linked reporter gene to visualize the expression of the iaa genes. The rate-limiting bacterial IAA-biosynthetic gene iaaM and the reporter gene for β-glucuronidase (GUS), uidA, were each fused to the cambial-region-specific Agrobacterium rhizogenes rolC promoter and linked on the same T-DNA. In situ hybridization of the iaaM gene confirmed that histochemical analysis of GUS activity could be used to predict iaaM gene expression. Moreover, quantitative fluorometric analysis of GUS activity allowed estimation of the level of de novo production of IAA in transgenic lines carrying a single-copy insert of the iaaM, uidA T-DNA. Microscale analysis of the IAA concentration across the cambial region tissues showed an increase in IAA concentration of about 35% to 40% in the two transgenic lines, but no changes in the radial distribution pattern of IAA compared with wild-type plants. This increase did not result in any changes in the developmental pattern of cambial derivatives or the cambial growth rate, which emphasizes the importance of the radial distribution pattern of IAA in controlling the development of secondary xylem, and suggests that a moderate increase in IAA concentration does not necessarily stimulate growth.

@article{lim_molecular_2000,
	title = {Molecular {Analysis} of the {SCARECROW} {Gene} in {Maize} {Reveals} a {Common} {Basis} for {Radial} {Patterning} in {Diverse} {Meristems}},
	volume = {12},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.12.8.1307},
	doi = {10.1105/tpc.12.8.1307},
	abstract = {Maize and Arabidopsis root apical meristems differ in several aspects of their radial organization and ontogeny. Despite the large evolutionary distance and differences in root radial patterning, analysis of the putative maize ortholog of the Arabidopsis patterning gene SCARECROW (SCR) revealed expression localized to the endodermis, which is similar to its expression in Arabidopsis. Expression in maize extends through the quiescent center, a population of mitotically inactive cells formerly thought to be undifferentiated and to lack radial pattern information. Zea mays SCARECROW (ZmSCR), the putative maize SCR ortholog, was used as a molecular marker to investigate radial patterning during regeneration of the root tip after either whole or partial excision. Analysis of the dynamic expression pattern of ZmSCR as well as other markers indicates the involvement of positional information as a primary determinant in regeneration of the root radial pattern.},
	number = {8},
	urldate = {2021-11-08},
	journal = {The Plant Cell},
	author = {Lim, Jun and Helariutta, Yrjo and Specht, Chelsea D. and Jung, Jee and Sims, Lynne and Bruce, Wesley B. and Diehn, Scott and Benfey, Philip N.},
	month = aug,
	year = {2000},
	pages = {1307--1318},
}

Maize and Arabidopsis root apical meristems differ in several aspects of their radial organization and ontogeny. Despite the large evolutionary distance and differences in root radial patterning, analysis of the putative maize ortholog of the Arabidopsis patterning gene SCARECROW (SCR) revealed expression localized to the endodermis, which is similar to its expression in Arabidopsis. Expression in maize extends through the quiescent center, a population of mitotically inactive cells formerly thought to be undifferentiated and to lack radial pattern information. Zea mays SCARECROW (ZmSCR), the putative maize SCR ortholog, was used as a molecular marker to investigate radial patterning during regeneration of the root tip after either whole or partial excision. Analysis of the dynamic expression pattern of ZmSCR as well as other markers indicates the involvement of positional information as a primary determinant in regeneration of the root radial pattern.

@article{grebe_conserved_2000,
	title = {A {Conserved} {Domain} of the {Arabidopsis} {GNOM} {Protein} {Mediates} {Subunit} {Interaction} and {Cyclophilin} 5 {Binding}},
	volume = {12},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.12.3.343},
	doi = {10.1105/tpc.12.3.343},
	abstract = {The Arabidopsis GNOM protein, a guanine nucleotide exchange factor (GEF) that acts on ADP ribosylation factor (ARF)–type G proteins, is required for coordination of cell polarity along the apical–basal embryo axis. Interallelic complementation of gnom mutants suggested that dimerization is involved in GNOM function. Here, direct interaction between GNOM molecules is demonstrated in vitro and by using a yeast two-hybrid system. Interaction was confined to an N-terminal domain conserved within a subgroup of large ARF GEFs. The same domain mediated in vitro binding to cyclophilin 5 (Cyp5), which was identified as a GNOM interactor in two-hybrid screening. Cyp5 displayed peptidylprolyl cis/trans–isomerase and protein refolding activities that were sensitive to cyclosporin A. Cyp5 protein accumulated in several plant organs and, like GNOM, was partitioned between cytosolic and membrane fractions. Cyp5 protein was also expressed in the developing embryo. Our results suggest that Cyp5 may regulate the ARF GEF function of the GNOM protein during embryogenesis.},
	number = {3},
	urldate = {2021-11-08},
	journal = {The Plant Cell},
	author = {Grebe, Markus and Gadea, José and Steinmann, Thomas and Kientz, Marika and Rahfeld, Jens-Ulrich and Salchert, Klaus and Koncz, Csaba and Jürgensa, Gerd},
	month = mar,
	year = {2000},
	pages = {343--356},
}

The Arabidopsis GNOM protein, a guanine nucleotide exchange factor (GEF) that acts on ADP ribosylation factor (ARF)–type G proteins, is required for coordination of cell polarity along the apical–basal embryo axis. Interallelic complementation of gnom mutants suggested that dimerization is involved in GNOM function. Here, direct interaction between GNOM molecules is demonstrated in vitro and by using a yeast two-hybrid system. Interaction was confined to an N-terminal domain conserved within a subgroup of large ARF GEFs. The same domain mediated in vitro binding to cyclophilin 5 (Cyp5), which was identified as a GNOM interactor in two-hybrid screening. Cyp5 displayed peptidylprolyl cis/trans–isomerase and protein refolding activities that were sensitive to cyclosporin A. Cyp5 protein accumulated in several plant organs and, like GNOM, was partitioned between cytosolic and membrane fractions. Cyp5 protein was also expressed in the developing embryo. Our results suggest that Cyp5 may regulate the ARF GEF function of the GNOM protein during embryogenesis.

@article{ogren_maintenance_2000,
	title = {Maintenance respiration correlates with sugar but not nitrogen concentration in dormant plants},
	volume = {108},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2000.108003295.x},
	doi = {10.1034/j.1399-3054.2000.108003295.x},
	abstract = {The range and source of variation in foliage respiration rate in the dormant season were investigated for plants of Lycopodium annotinum L., Pinus contorta Dougl. var. latifolia Engelm., Picea abies (L.) Karst., Andromeda polifolia L., Calluna vulgaris (L.) Hull, Vaccinium myrtillus L., Vaccinium vitis-ideae L. and Empetrum hermaphroditum Hagerup. Field-grown plants were transferred to a cold room kept at 5°C in late autumn and then analysed for the foliage respiration rate in relation to nitrogen and sugar concentration over a period of many weeks. Respiration rate varied 1.6-fold among species at a given time, and decreased with time as long as plants remained dormant. Most of both sources of variation were accounted for by the same linear and positive correlation with total soluble sugar concentration, whereas no relationship with nitrogen concentration was found. The hypothesis presented is that respiration rate correlates with sugar concentration in the dormant season because cellular sugar concentrations are much increased and, thereby, the costs of maintaining concentration gradients. Pinus contorta had a significantly higher respiration rate for a given sugar concentration than any other species, and therefore suffered larger relative losses of sugars when kept at 5°C; possible reasons and consequences of this are discussed in relation to field performance.},
	language = {en},
	number = {3},
	urldate = {2021-11-08},
	journal = {Physiologia Plantarum},
	author = {Ögren, Erling},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2000.108003295.x},
	pages = {295--299},
}

The range and source of variation in foliage respiration rate in the dormant season were investigated for plants of Lycopodium annotinum L., Pinus contorta Dougl. var. latifolia Engelm., Picea abies (L.) Karst., Andromeda polifolia L., Calluna vulgaris (L.) Hull, Vaccinium myrtillus L., Vaccinium vitis-ideae L. and Empetrum hermaphroditum Hagerup. Field-grown plants were transferred to a cold room kept at 5°C in late autumn and then analysed for the foliage respiration rate in relation to nitrogen and sugar concentration over a period of many weeks. Respiration rate varied 1.6-fold among species at a given time, and decreased with time as long as plants remained dormant. Most of both sources of variation were accounted for by the same linear and positive correlation with total soluble sugar concentration, whereas no relationship with nitrogen concentration was found. The hypothesis presented is that respiration rate correlates with sugar concentration in the dormant season because cellular sugar concentrations are much increased and, thereby, the costs of maintaining concentration gradients. Pinus contorta had a significantly higher respiration rate for a given sugar concentration than any other species, and therefore suffered larger relative losses of sugars when kept at 5°C; possible reasons and consequences of this are discussed in relation to field performance.

@article{schoefs_photoactive_2000,
	title = {Photoactive {Protochlorophyllide} {Regeneration} in {Cotyledons} and {Leaves} from {Higher} {Plants}†,¶},
	volume = {72},
	issn = {0031-8655, 1751-1097},
	url = {https://bioone.org/journals/photochemistry-and-photobiology/volume-72/issue-5/0031-8655_2000_072_0660_PPRICA_2.0.CO_2/Photoactive-Protochlorophyllide-Regeneration-in-Cotyledons-and-Leaves-from-Higher-Plants/10.1562/0031-8655(2000)072<0660:PPRICA>2.0.CO;2.full},
	doi = {10.1562/0031-8655(2000)072<0660:PPRICA>2.0.CO;2},
	abstract = {Chlorophyll accumulation during greening implies the continuous transformation of photoactive protochlorophyllide (Pchlide) to chlorophyllide. Since this reaction is a light-dependent step, the study of regeneration of photoactive Pchlide under a continuous illumination is difficult. Therefore this process is best studied on etiolated plants during a period of darkness following the initial photoreduction of photoactive Pchlide. In this study, the regeneration process has been studied using spinach cotyledons, as well as barley and bean leaves, illuminated by a single saturating flash. The regeneration was characterized using 77 K fluorescence emission and excitation spectra and high-performance liquid chromatography. The fluorescence data indicated that the same spectral forms of photoactive Pchlide are regenerated by different pathways: (1) photoactive Pchlide regeneration starts immediately after the photoreduction through the formation of a nonphotoactive Pchlide form, emitting fluorescence at approximately 651 nm. This form is similar to the large aggregate of photoactive Pchlide present before the illumination, but it contains oxidized form of nicotinamide adenine dinucleotide phosphate, instead of the reduced form (NADPH), in the ternary complexes; and (2) after the dislocation of the large aggregates of chlorophyllide–light-dependent NADPH:Pchlide a photooxidoreductase–NADPH ternary complexes, the regeneration occurs at the expense of the several nonphotoactive Pchlide spectral forms present before the illumination.},
	number = {5},
	urldate = {2021-11-08},
	journal = {Photochemistry and Photobiology},
	author = {Schoefs, Benoît and Bertrand, Martine and Funk, Christiane},
	month = nov,
	year = {2000},
	note = {Publisher: American Society for Photobiology},
	pages = {660--668},
}

Chlorophyll accumulation during greening implies the continuous transformation of photoactive protochlorophyllide (Pchlide) to chlorophyllide. Since this reaction is a light-dependent step, the study of regeneration of photoactive Pchlide under a continuous illumination is difficult. Therefore this process is best studied on etiolated plants during a period of darkness following the initial photoreduction of photoactive Pchlide. In this study, the regeneration process has been studied using spinach cotyledons, as well as barley and bean leaves, illuminated by a single saturating flash. The regeneration was characterized using 77 K fluorescence emission and excitation spectra and high-performance liquid chromatography. The fluorescence data indicated that the same spectral forms of photoactive Pchlide are regenerated by different pathways: (1) photoactive Pchlide regeneration starts immediately after the photoreduction through the formation of a nonphotoactive Pchlide form, emitting fluorescence at approximately 651 nm. This form is similar to the large aggregate of photoactive Pchlide present before the illumination, but it contains oxidized form of nicotinamide adenine dinucleotide phosphate, instead of the reduced form (NADPH), in the ternary complexes; and (2) after the dislocation of the large aggregates of chlorophyllide–light-dependent NADPH:Pchlide a photooxidoreductase–NADPH ternary complexes, the regeneration occurs at the expense of the several nonphotoactive Pchlide spectral forms present before the illumination.

@article{nield_supermolecular_2000,
	title = {Supermolecular structure of photosystem {II} and location of the {PsbS} protein.},
	volume = {355},
	issn = {0962-8436},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692865/},
	abstract = {This paper addresses the question of whether the PsbS protein of photosystem two (PS II) is located within the LHC II PS II supercomplex for which a three-dimensional structure has been obtained by cryoelectron microscopy and single particle analysis. The PsbS protein has recently been implicated as the site for non-photochemical quenching. Based both on immunoblotting analyses and structural considerations of an improved model of the spinach LHC II PS II supercomplex, we conclude that the PsbS protein is not located within the supercomplex. Analyses of other fractions resulting from the solubilization of PS Il-enriched membranes derived from spinach suggest that the PsbS protein is located in the LHC II-rich regions that interconnect the supercomplex within the membrane.},
	number = {1402},
	urldate = {2021-11-08},
	journal = {Philosophical Transactions of the Royal Society B: Biological Sciences},
	author = {Nield, J and Funk, C and Barber, J},
	month = oct,
	year = {2000},
	pmid = {11127988},
	pmcid = {PMC1692865},
	pages = {1337--1344},
}

This paper addresses the question of whether the PsbS protein of photosystem two (PS II) is located within the LHC II PS II supercomplex for which a three-dimensional structure has been obtained by cryoelectron microscopy and single particle analysis. The PsbS protein has recently been implicated as the site for non-photochemical quenching. Based both on immunoblotting analyses and structural considerations of an improved model of the spinach LHC II PS II supercomplex, we conclude that the PsbS protein is not located within the supercomplex. Analyses of other fractions resulting from the solubilization of PS Il-enriched membranes derived from spinach suggest that the PsbS protein is located in the LHC II-rich regions that interconnect the supercomplex within the membrane.

@article{mullineaux_are_2000,
	title = {Are diverse signalling pathways integrated in the regulation of arabidopsis antioxidant defence gene expression in response to excess excitation energy?},
	volume = {355},
	issn = {0962-8436},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692875/},
	abstract = {When low-light-grown Arabidopsis rosettes are partially exposed to excess light (EL), the unexposed leaves become acclimated to excess excitation energy (EEE) and consequent photo-oxidative stress. This phenomenon, termed systemic acquired acclimation (SAA), is associated with redox changes in the proximity of photosystem II, changes in foliar H2O2 content and induction of antioxidant defences. The induction of extra-plastidial antioxidant systems is important in the protection of the chloroplast under EL conditions. A larger range of transcripts encoding different antioxidant defence enzymes may be induced in the systemically acclimated leaves and these include those encoded by the glutathione peroxidase (GPX2) and glutathione-S-transferase (GST) genes, which are also highly induced in the hypersensitive response and associated systemic acquired resistance (SAR) in incompatible plant-pathogen interactions. Furthermore, the expression of the SAR-inducible pathogenesis-related protein gene, PR2, is enhanced in SAA leaves. Wounded leaf tissue also shows enhanced systemic induction of a cytosolic ascorbate peroxidase gene (APX2) under EL conditions. These and other considerations, suggest H2O2 and other reactive oxygen species (ROS) could be the common factor in signalling pathways for diverse environmental stresses. These effects may be mediated by changes in the level and redox state of the cellular glutathione pool. Mutants with constitutive expression of a normally EL-inducible APX2 gene have much reduced levels of foliar glutathione. The expression of APX1 and APX3, encoding cytosolic and peroxisome-associated isoforms, respectively, are also under phytochrome-A-mediated control. The expression of these genes is tightly linked to the greening of plastids in etiolated seedlings. These data suggest that part of the developmental processes that bring about the acclimation of leaves to high light includes the configuration of antioxidant defences. Therefore, the linkage between immediate responses of leaves to EL, acclimation of chloroplasts to EEE and the subsequent changes to leaf form and function in high light could be mediated by the activity of foliar antioxidant defences and changes in the concentration of ROS.},
	number = {1402},
	urldate = {2021-11-08},
	journal = {Philosophical Transactions of the Royal Society B: Biological Sciences},
	author = {Mullineaux, P and Ball, L and Escobar, C and Karpinska, B and Creissen, G and Karpinski, S},
	month = oct,
	year = {2000},
	pmid = {11128006},
	pmcid = {PMC1692875},
	pages = {1531--1540},
}

When low-light-grown Arabidopsis rosettes are partially exposed to excess light (EL), the unexposed leaves become acclimated to excess excitation energy (EEE) and consequent photo-oxidative stress. This phenomenon, termed systemic acquired acclimation (SAA), is associated with redox changes in the proximity of photosystem II, changes in foliar H2O2 content and induction of antioxidant defences. The induction of extra-plastidial antioxidant systems is important in the protection of the chloroplast under EL conditions. A larger range of transcripts encoding different antioxidant defence enzymes may be induced in the systemically acclimated leaves and these include those encoded by the glutathione peroxidase (GPX2) and glutathione-S-transferase (GST) genes, which are also highly induced in the hypersensitive response and associated systemic acquired resistance (SAR) in incompatible plant-pathogen interactions. Furthermore, the expression of the SAR-inducible pathogenesis-related protein gene, PR2, is enhanced in SAA leaves. Wounded leaf tissue also shows enhanced systemic induction of a cytosolic ascorbate peroxidase gene (APX2) under EL conditions. These and other considerations, suggest H2O2 and other reactive oxygen species (ROS) could be the common factor in signalling pathways for diverse environmental stresses. These effects may be mediated by changes in the level and redox state of the cellular glutathione pool. Mutants with constitutive expression of a normally EL-inducible APX2 gene have much reduced levels of foliar glutathione. The expression of APX1 and APX3, encoding cytosolic and peroxisome-associated isoforms, respectively, are also under phytochrome-A-mediated control. The expression of these genes is tightly linked to the greening of plastids in etiolated seedlings. These data suggest that part of the developmental processes that bring about the acclimation of leaves to high light includes the configuration of antioxidant defences. Therefore, the linkage between immediate responses of leaves to EL, acclimation of chloroplasts to EEE and the subsequent changes to leaf form and function in high light could be mediated by the activity of foliar antioxidant defences and changes in the concentration of ROS.

@article{ingvarsson_exploitative_2000,
	title = {Exploitative competition between two seed parasites on the common sedge, {Carex} nigra},
	volume = {91},
	issn = {1600-0706},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1600-0706.2000.910216.x},
	doi = {10.1034/j.1600-0706.2000.910216.x},
	abstract = {We present results from a two-year experiment studying the competitive interaction between the gall mite Phytoptus caricis and the smut fungus Anthracoidea heterospora. A factorial addition/removal experiment showed that a negative interaction occurs between A. heterospora and P. caricis, presumably due to competitive interactions in the early infection process of their shared resource, developing utricles on the common sedge, C. nigra. Strong effects of interspecific competition for both species were only evident in 1995 while A. heterospora showed some signs of suffering negative effects from competition also in 1994. Results thus suggest that significant effects of competitive interaction may only be apparent when densities of the two competitors are fairly high. The interaction was strongly asymmetric, with A. heterospora being more affected by the presence of P. caricis than vice versa. Estimates of interaction strength for A. heterospora were about twice as large compared to that for P. caricis. The difference in interaction was significant when data were pooled over the two years of the study. The study highlights the need to consider interspecific interactions between different plant parasites when studying the effects of plant pathogens.},
	language = {en},
	number = {2},
	urldate = {2021-11-08},
	journal = {Oikos},
	author = {Ingvarsson, Pär K. and Ericson, Lars},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1600-0706.2000.910216.x},
	pages = {362--370},
}

We present results from a two-year experiment studying the competitive interaction between the gall mite Phytoptus caricis and the smut fungus Anthracoidea heterospora. A factorial addition/removal experiment showed that a negative interaction occurs between A. heterospora and P. caricis, presumably due to competitive interactions in the early infection process of their shared resource, developing utricles on the common sedge, C. nigra. Strong effects of interspecific competition for both species were only evident in 1995 while A. heterospora showed some signs of suffering negative effects from competition also in 1994. Results thus suggest that significant effects of competitive interaction may only be apparent when densities of the two competitors are fairly high. The interaction was strongly asymmetric, with A. heterospora being more affected by the presence of P. caricis than vice versa. Estimates of interaction strength for A. heterospora were about twice as large compared to that for P. caricis. The difference in interaction was significant when data were pooled over the two years of the study. The study highlights the need to consider interspecific interactions between different plant parasites when studying the effects of plant pathogens.

@article{lindgren_model_2000,
	title = {A model integrating seed source adaptation and seed use},
	volume = {20},
	issn = {1573-5095},
	url = {https://doi.org/10.1023/A:1006708213824},
	doi = {10.1023/A:1006708213824},
	abstract = {A conceptual model that considers theperformance (adaptability) of a seed source (=anorigin) and the location or range of its deployment isdeveloped employing the Cauchy function. The modelassumes that there exists an optimal site type foreach provenance origin (genetic material), and thatloss in performance is a function of the “distance” (ameasure of increasing maladaptation) from the optimalsite. The model requires the estimate of threeparameters: a site requirement value that measuressite type in one dimension; a measure of optimalperformance; and a flexibility measure of the width ofseed source adaptability. The Cauchy function has aknown integral, thus the average adaptability over arange (a possible seed use zone) can be mathematicallyevaluated. The model was also extended to seed orchardcrops representing progeny of parents of variableorigins. Scots pine information in Sweden was used todemonstrate possible applications of the model.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {New Forests},
	author = {Lindgren, D. and Ying, C.C.},
	month = jul,
	year = {2000},
	pages = {87--104},
}

A conceptual model that considers theperformance (adaptability) of a seed source (=anorigin) and the location or range of its deployment isdeveloped employing the Cauchy function. The modelassumes that there exists an optimal site type foreach provenance origin (genetic material), and thatloss in performance is a function of the “distance” (ameasure of increasing maladaptation) from the optimalsite. The model requires the estimate of threeparameters: a site requirement value that measuressite type in one dimension; a measure of optimalperformance; and a flexibility measure of the width ofseed source adaptability. The Cauchy function has aknown integral, thus the average adaptability over arange (a possible seed use zone) can be mathematicallyevaluated. The model was also extended to seed orchardcrops representing progeny of parents of variableorigins. Scots pine information in Sweden was used todemonstrate possible applications of the model.

@article{li_pigment-binding_2000,
	title = {A pigment-binding protein essential for regulation of photosynthetic light harvesting},
	volume = {403},
	copyright = {2000 Macmillan Magazines Ltd.},
	issn = {1476-4687},
	url = {https://www.nature.com/articles/35000131},
	doi = {10.1038/35000131},
	abstract = {Photosynthetic light harvesting in plants is regulated in response to changes in incident light intensity. Absorption of light that exceeds a plant's capacity for fixation of CO2 results in thermal dissipation of excitation energy in the pigment antenna of photosystem II by a poorly understood mechanism. This regulatory process, termed nonphotochemical quenching, maintains the balance between dissipation and utilization of light energy to minimize generation of oxidizing molecules, thereby protecting the plant against photo-oxidative damage. To identify specific proteins that are involved in nonphotochemical quenching, we have isolated mutants of Arabidopsis thaliana that cannot dissipate excess absorbed light energy. Here we show that the gene encoding PsbS, an intrinsic chlorophyll-binding protein of photosystem II, is necessary for nonphotochemical quenching but not for efficient light harvesting and photosynthesis. These results indicate that PsbS may be the site for nonphotochemical quenching, a finding that has implications for the functional evolution of pigment-binding proteins.},
	language = {en},
	number = {6768},
	urldate = {2021-11-08},
	journal = {Nature},
	author = {Li, Xiao-Ping and Björkman, Olle and Shih, Connie and Grossman, Arthur R. and Rosenquist, Magnus and Jansson, Stefan and Niyogi, Krishna K.},
	month = jan,
	year = {2000},
	note = {Bandiera\_abtest: a
Cg\_type: Nature Research Journals
Number: 6768
Primary\_atype: Research
Publisher: Nature Publishing Group},
	keywords = {Humanities and Social Sciences, Science, multidisciplinary},
	pages = {391--395},
}

Photosynthetic light harvesting in plants is regulated in response to changes in incident light intensity. Absorption of light that exceeds a plant's capacity for fixation of CO2 results in thermal dissipation of excitation energy in the pigment antenna of photosystem II by a poorly understood mechanism. This regulatory process, termed nonphotochemical quenching, maintains the balance between dissipation and utilization of light energy to minimize generation of oxidizing molecules, thereby protecting the plant against photo-oxidative damage. To identify specific proteins that are involved in nonphotochemical quenching, we have isolated mutants of Arabidopsis thaliana that cannot dissipate excess absorbed light energy. Here we show that the gene encoding PsbS, an intrinsic chlorophyll-binding protein of photosystem II, is necessary for nonphotochemical quenching but not for efficient light harvesting and photosynthesis. These results indicate that PsbS may be the site for nonphotochemical quenching, a finding that has implications for the functional evolution of pigment-binding proteins.

@article{eriksson_increased_2000,
	title = {Increased gibberellin biosynthesis in transgenic trees promotes growth, biomass production and xylem fiber length},
	volume = {18},
	copyright = {2000 Nature America Inc.},
	issn = {1546-1696},
	url = {https://www.nature.com/articles/nbt0700_784},
	doi = {10.1038/77355},
	abstract = {In most tree-breeding programs worldwide, increasing the trees' growth rates and stem volumes and shortening their rotation times are important aims. Such trees would yield more biomass per unit area. Here we show that overexpressing a key regulatory gene in the biosynthesis of the plant hormone gibberellin (GA) in hybrid aspen (Populus tremula × P. tremuloides) improves growth rate and biomass. In addition, these transgenic trees have more numerous and longer xylem fibers than unmodified wild-type (wt) plants. Long fibers are desirable in the production of strong paper, but it has not as yet proved possible to influence this trait by traditional breeding techniques. We also show that GA has an antagonistic effect on root initiation, as the transgenic lines showed poorer rooting than the control plants when potted in soil. However, the negative effect on rooting efficiencies in the initial establishment of young plantlets in the growth chamber did not significantly affect root growth at later stages.},
	language = {en},
	number = {7},
	urldate = {2021-11-08},
	journal = {Nature Biotechnology},
	author = {Eriksson, Maria E. and Israelsson, Maria and Olsson, Olof and Moritz, Thomas},
	month = jul,
	year = {2000},
	note = {Bandiera\_abtest: a
Cg\_type: Nature Research Journals
Number: 7
Primary\_atype: Research
Publisher: Nature Publishing Group},
	keywords = {Agriculture, Bioinformatics, Biomedical Engineering/Biotechnology, Biomedicine, Biotechnology, Life Sciences, general},
	pages = {784--788},
}

In most tree-breeding programs worldwide, increasing the trees' growth rates and stem volumes and shortening their rotation times are important aims. Such trees would yield more biomass per unit area. Here we show that overexpressing a key regulatory gene in the biosynthesis of the plant hormone gibberellin (GA) in hybrid aspen (Populus tremula × P. tremuloides) improves growth rate and biomass. In addition, these transgenic trees have more numerous and longer xylem fibers than unmodified wild-type (wt) plants. Long fibers are desirable in the production of strong paper, but it has not as yet proved possible to influence this trait by traditional breeding techniques. We also show that GA has an antagonistic effect on root initiation, as the transgenic lines showed poorer rooting than the control plants when potted in soil. However, the negative effect on rooting efficiencies in the initial establishment of young plantlets in the growth chamber did not significantly affect root growth at later stages.

@article{lerceteau_aflp_2000,
	title = {{AFLP} mapping and detection of quantitative trait loci ({QTLs}) for economically important traits in {Pinus} sylvestris: a preliminary study},
	volume = {6},
	issn = {1572-9788},
	shorttitle = {{AFLP} mapping and detection of quantitative trait loci ({QTLs}) for economically important traits in {Pinus} sylvestris},
	url = {https://doi.org/10.1023/A:1026548716320},
	doi = {10.1023/A:1026548716320},
	abstract = {We have applied a two-way pseudo-testcross strategy in an analysis of Pinus sylvestris for genetic mapping and detection of quantitative trait loci (QTLs) associated with economically important traits targeted in the Swedish tree-breeding programme. Based on 94 full-sib progeny of a cross between two plus-trees from northern Sweden we generated two parental maps using AFLP markers. The female map was comprised of 94 markers assigned to 15 linkage groups giving a size of 796 cM. On the male map 155 markers were assigned to 15 linkage groups, giving a total size of 1335 cM. The recombination frequency was found to be sex-dependent, being 29.3\% higher in male than in female gametes. On the female map, 12 QTLs were detected (but none for branch diameter or wood density). Three QTLs for tree height accounted for 25.8\% of the total phenotypic variation of this trait. When the QTLs detected for all the traits were taken independently, the percentages of phenotypic variance ranged from 9.3\% to 22.7\%. The highest value was observed for frost hardiness, an important trait in northern Sweden for which a major gene seemed to be involved. A cluster of QTLs for tree height, trunk diameter and volume was located on one linkage group. On the male map, four QTLs for trunk diameter and volume were detected. Due to the reduced number of individuals under study, the results are preliminary and have to be validated on more trees.},
	language = {en},
	number = {5},
	urldate = {2021-11-08},
	journal = {Molecular Breeding},
	author = {Lerceteau, Estelle and Plomion, Christophe and Andersson, Bengt},
	month = oct,
	year = {2000},
	pages = {451--458},
}

We have applied a two-way pseudo-testcross strategy in an analysis of Pinus sylvestris for genetic mapping and detection of quantitative trait loci (QTLs) associated with economically important traits targeted in the Swedish tree-breeding programme. Based on 94 full-sib progeny of a cross between two plus-trees from northern Sweden we generated two parental maps using AFLP markers. The female map was comprised of 94 markers assigned to 15 linkage groups giving a size of 796 cM. On the male map 155 markers were assigned to 15 linkage groups, giving a total size of 1335 cM. The recombination frequency was found to be sex-dependent, being 29.3% higher in male than in female gametes. On the female map, 12 QTLs were detected (but none for branch diameter or wood density). Three QTLs for tree height accounted for 25.8% of the total phenotypic variation of this trait. When the QTLs detected for all the traits were taken independently, the percentages of phenotypic variance ranged from 9.3% to 22.7%. The highest value was observed for frost hardiness, an important trait in northern Sweden for which a major gene seemed to be involved. A cluster of QTLs for tree height, trunk diameter and volume was located on one linkage group. On the male map, four QTLs for trunk diameter and volume were detected. Due to the reduced number of individuals under study, the results are preliminary and have to be validated on more trees.

@article{karlsson_sequencing_2000,
	title = {Sequencing of the {Francisella} tularensis {Strain} {Schu} 4 {Genome} {Reveals} the {Shikimate} and {Purine} {Metabolic} {Pathways}, {Targets} for the {Construction} of a {Rationally} {Attenuated} {Auxotrophic} {Vaccine}},
	volume = {5},
	issn = {1090-6592},
	url = {https://www.liebertpub.com/doi/10.1089/10906590050145249},
	doi = {10.1089/10906590050145249},
	abstract = {Francisella tularensis is the etiological agent of tularemia, a serious disease in several Northern hemisphere countries. The organism has fastidious growth requirements and is very poorly understood at the genetic and molecular levels. Given the lack of data on this organism, we undertook the sample sequencing of its genome. A random library of DNA fragments from a highly virulent strain (Schu 4) of F. tularensis was constructed and the nucleotide sequences of 13,904 cloned fragments were determined and assembled into 353 contigs. A total of 1.83 Mb of nucleotide sequence was obtained that had a G + C content of 33.2\%. Genes located on plasmids pOM1 and pNFL10, which had been previously isolated from low virulence strains of F. tularensis, were absent but all of the other known F. tularensis genes were represented in the assembled data. F. tularensis Schu4 was able to grow in the absence of aromatic amino acids and orthologues of genes which could encode enzymes in the shikimate pathway in other bacteria were identified in the assembled data. Genes that could encode all of the enzymes in the purine biosynthetic and most of the enzymes in the purine salvage pathways were also identified. This data will be used to develop defined rationally attenuated mutants of F. tularensis, which could be used as replacements for the existing genetically undefined live vaccine strain.},
	number = {1},
	urldate = {2021-11-08},
	journal = {Microbial \& Comparative Genomics},
	author = {Karlsson, Jan and Prior, Richard G. and Williams, Kerstin and Lindler, Luther and Brown, Katherine A. and Chatwell, Nicola and Hjalmarsson, Karin and Loman, Nick and Mack, Kerri A. and Pallen, Mark and Popek, Michael and Sandström, Gunnar and Sjöstedt, Anders and Svensson, Thomas and Tamas, Ivica and Andersson, Siv G. E. and Wren, Brendan W. and Oyston, Petra C. F. and Titball, Richard W.},
	month = mar,
	year = {2000},
	note = {Publisher: Mary Ann Liebert, Inc., publishers},
	pages = {25--39},
}

Francisella tularensis is the etiological agent of tularemia, a serious disease in several Northern hemisphere countries. The organism has fastidious growth requirements and is very poorly understood at the genetic and molecular levels. Given the lack of data on this organism, we undertook the sample sequencing of its genome. A random library of DNA fragments from a highly virulent strain (Schu 4) of F. tularensis was constructed and the nucleotide sequences of 13,904 cloned fragments were determined and assembled into 353 contigs. A total of 1.83 Mb of nucleotide sequence was obtained that had a G + C content of 33.2%. Genes located on plasmids pOM1 and pNFL10, which had been previously isolated from low virulence strains of F. tularensis, were absent but all of the other known F. tularensis genes were represented in the assembled data. F. tularensis Schu4 was able to grow in the absence of aromatic amino acids and orthologues of genes which could encode enzymes in the shikimate pathway in other bacteria were identified in the assembled data. Genes that could encode all of the enzymes in the purine biosynthetic and most of the enzymes in the purine salvage pathways were also identified. This data will be used to develop defined rationally attenuated mutants of F. tularensis, which could be used as replacements for the existing genetically undefined live vaccine strain.

@article{waldmann_comparison_2000,
	title = {Comparison of genetic (co)variance matrices within and between {Scabiosa} canescens and {S}. columbaria},
	volume = {13},
	issn = {1420-9101},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1420-9101.2000.00214.x},
	doi = {10.1046/j.1420-9101.2000.00214.x},
	abstract = {In the current study, we used bootstrap analyses and the common principal component (CPC) method of Flury (1988) to estimate and compare the G-matrix of Scabiosa columbaria and S. canescens populations. We found three major patterns in the G-matrices: (i) the magnitude of the (co)variances was more variable among characters than among populations, (ii) different populations showed high (co)variance for different characters, and (iii) there was a tendency for S. canescens to have higher genetic (co)variances than S. columbaria. The hypothesis of equal G-matrices was rejected in all comparisons and there was no evidence that the matrices differed by a proportional constant in any of the analyses. The two ‘species matrices’ were found to be unrelated, both for raw data and data standardized over populations, and there was significant between-population variation in the G-matrix in both species. Populations of S. canescens showed conservation of structure (principal components) in their G-matrices, contrasting with the lack of common structure among the S. columbaria matrices. Given these observations and the results from previous studies, we propose that selection may be responsible for some of the variation between the G-matrices, at least in S. columbaria and at the between-species level.},
	language = {en},
	number = {5},
	urldate = {2021-11-08},
	journal = {Journal of Evolutionary Biology},
	author = {{Waldmann} and {Andersson}},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1420-9101.2000.00214.x},
	keywords = {Scabiosa, genetic (co)variance matrices, hierarchical CPC comparison, quantitative genetics, resampling},
	pages = {826--835},
}

In the current study, we used bootstrap analyses and the common principal component (CPC) method of Flury (1988) to estimate and compare the G-matrix of Scabiosa columbaria and S. canescens populations. We found three major patterns in the G-matrices: (i) the magnitude of the (co)variances was more variable among characters than among populations, (ii) different populations showed high (co)variance for different characters, and (iii) there was a tendency for S. canescens to have higher genetic (co)variances than S. columbaria. The hypothesis of equal G-matrices was rejected in all comparisons and there was no evidence that the matrices differed by a proportional constant in any of the analyses. The two ‘species matrices’ were found to be unrelated, both for raw data and data standardized over populations, and there was significant between-population variation in the G-matrix in both species. Populations of S. canescens showed conservation of structure (principal components) in their G-matrices, contrasting with the lack of common structure among the S. columbaria matrices. Given these observations and the results from previous studies, we propose that selection may be responsible for some of the variation between the G-matrices, at least in S. columbaria and at the between-species level.

@article{clarke_truncated_2000,
	title = {The {Truncated} {Form} of the {Bacterial} {Heat} {Shock} {Protein}  {ClpB}/{HSP100} {Contributes} to {Development} of {Thermotolerance}  in the {Cyanobacterium} {Synechococcus} sp. {Strain} {PCC} 7942},
	volume = {182},
	issn = {0021-9193},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC94841/},
	abstract = {ClpB is a highly conserved heat shock protein that is essential for thermotolerance in bacteria and eukaryotes. One distinctive feature of all bacterial clpB genes is the dual translation of a truncated 79-kDa form (ClpB-79) in addition to the full-length 93-kDa protein (ClpB-93). To investigate the currently unknown function of ClpB-79, we have examined the ability of the two different-sized ClpB homologues from the cyanobacterium Synechococcus sp. strain PCC 7942 to confer thermotolerance. We show that the ClpB-79 form has the same capacity as ClpB-93 to confer thermotolerance and that the ClpB-79 protein contributes ca. one-third of the total thermotolerance developed in wild-type Synechococcus, the first in vivo demonstration of a functional role for ClpB-79 in bacteria.},
	number = {24},
	urldate = {2021-11-08},
	journal = {Journal of Bacteriology},
	author = {Clarke, Adrian K. and Eriksson, Mats-Jerry},
	month = dec,
	year = {2000},
	pmid = {11092876},
	pmcid = {PMC94841},
	pages = {7092--7096},
}

ClpB is a highly conserved heat shock protein that is essential for thermotolerance in bacteria and eukaryotes. One distinctive feature of all bacterial clpB genes is the dual translation of a truncated 79-kDa form (ClpB-79) in addition to the full-length 93-kDa protein (ClpB-93). To investigate the currently unknown function of ClpB-79, we have examined the ability of the two different-sized ClpB homologues from the cyanobacterium Synechococcus sp. strain PCC 7942 to confer thermotolerance. We show that the ClpB-79 form has the same capacity as ClpB-93 to confer thermotolerance and that the ClpB-79 protein contributes ca. one-third of the total thermotolerance developed in wild-type Synechococcus, the first in vivo demonstration of a functional role for ClpB-79 in bacteria.

@article{rosenquist_evolution_2000,
	title = {Evolution of the 14-3-3 {Protein} {Family}: {Does} the {Large} {Number} of {Isoforms} in {Multicellular} {Organisms} {Reflect} {Functional} {Specificity}?},
	volume = {51},
	issn = {1432-1432},
	shorttitle = {Evolution of the 14-3-3 {Protein} {Family}},
	url = {https://doi.org/10.1007/s002390010107},
	doi = {10.1007/s002390010107},
	abstract = {14-3-3 proteins constitute a family of eukaryotic proteins that are key regulators of a large number of processes ranging from mitosis to apoptosis. 14-3-3s function as dimers and bind to particular motifs in their target proteins. To date, 14-3-3s have been implicated in regulation or stabilization of more than 35 different proteins. This number is probably only a fraction of the number of proteins that 14-3-3s bind to, as reports of new target proteins have become more frequent. An examination of 14-3-3 entries in the public databases reveals 153 isoforms, including alleloforms, reported in 48 different species. The number of isoforms range from 2, in the unicellular organism Saccharomyces cerevisiae, to 12 in the multicellular organism Arabidopsis thaliana. A phylogenetic analysis reveals that there are four major evolutionary lineages: Viridiplantae (plants), Fungi, Alveolata, and Metazoa (animals). A close examination of the aligned amino acid sequences identifies conserved amino acid residues and regions of importance for monomer stabilization, dimer formation, target protein binding, and the nuclear export function. Given the fact that 53\% of the protein is conserved, including all amino acid residues in the target binding groove of the 14-3-3 monomer, one might expect little to no isoform specificity for target protein binding. However, using surface plasmon resonance we show that there are large differences in affinity between nine 14-3-3 isoforms of A. thaliana and a target peptide representing a novel binding motif present in the C terminus of the plant plasma membrane H+ATPase. Thus, our data suggest that one reason for the large number of isoforms found in multicellular organisms is isoform-specific functions.},
	language = {en},
	number = {5},
	urldate = {2021-11-08},
	journal = {Journal of Molecular Evolution},
	author = {Rosenquist, Magnus and Sehnke, Paul and Ferl, Robert J. and Sommarin, Marianne and Larsson, Christer},
	month = nov,
	year = {2000},
	pages = {446--458},
}

14-3-3 proteins constitute a family of eukaryotic proteins that are key regulators of a large number of processes ranging from mitosis to apoptosis. 14-3-3s function as dimers and bind to particular motifs in their target proteins. To date, 14-3-3s have been implicated in regulation or stabilization of more than 35 different proteins. This number is probably only a fraction of the number of proteins that 14-3-3s bind to, as reports of new target proteins have become more frequent. An examination of 14-3-3 entries in the public databases reveals 153 isoforms, including alleloforms, reported in 48 different species. The number of isoforms range from 2, in the unicellular organism Saccharomyces cerevisiae, to 12 in the multicellular organism Arabidopsis thaliana. A phylogenetic analysis reveals that there are four major evolutionary lineages: Viridiplantae (plants), Fungi, Alveolata, and Metazoa (animals). A close examination of the aligned amino acid sequences identifies conserved amino acid residues and regions of importance for monomer stabilization, dimer formation, target protein binding, and the nuclear export function. Given the fact that 53% of the protein is conserved, including all amino acid residues in the target binding groove of the 14-3-3 monomer, one might expect little to no isoform specificity for target protein binding. However, using surface plasmon resonance we show that there are large differences in affinity between nine 14-3-3 isoforms of A. thaliana and a target peptide representing a novel binding motif present in the C terminus of the plant plasma membrane H+ATPase. Thus, our data suggest that one reason for the large number of isoforms found in multicellular organisms is isoform-specific functions.

@article{tavares_simple_2000,
	title = {A simple, rapid and non-destructive procedure to extract cell wall-associated proteins from {Frankia}},
	volume = {39},
	issn = {0167-7012},
	url = {https://www.sciencedirect.com/science/article/pii/S0167701299001153},
	doi = {10.1016/S0167-7012(99)00115-3},
	abstract = {A simple cell fractionation procedure was developed to extract cell wall-associated proteins from the nitrogen-fixing actinomycete Frankia. The method was based on washing Frankia mycelia in 62.5 mM Tris–HCl (pH 6.8) buffer supplemented with 0.1\% Triton X-100 as solubilizing agent. Cell wall-associated proteins were efficiently extracted in less than 10 min, recovering approximately 94.5±7.44 μg protein per extraction procedure from exponentially growing cells corresponding to 50 ml of culture. The amount of cell lysis occurring during the cell wall extraction was estimated to be 1.50±0.51\%. Three peptidoglycan hydrolases with apparent molecular masses of 4.7, 12.1, and 17.8 kDa were detected by zymography in the cell wall-associated protein fraction. On the contrary, no cell wall lytic enzyme was detected in the cytoplasmic protein fraction. These results indicate that the present method enables a specific extraction of cell wall-associated proteins. Moreover, fluorescein isothiocyanate (FITC) labelling of the cell surface proteins showed an efficient removal of cell wall-associated proteins. Growth of the treated Frankia cells (i.e. cells from which the cell wall-associated proteins were removed) in semi-solid media suggested that these cells were still viable. This technique is of importance for functionality studies of cell wall-associated proteins, particularly for bacteria where traditional cell fractionation methods are difficult to be applied.},
	language = {en},
	number = {2},
	urldate = {2021-11-08},
	journal = {Journal of Microbiological Methods},
	author = {Tavares, Fernando and Sellstedt, Anita},
	month = jan,
	year = {2000},
	keywords = {Actinomycetes, Cell fractionation, Gram-positive cell wall, Peptidoglycan hydrolases},
	pages = {171--178},
}

A simple cell fractionation procedure was developed to extract cell wall-associated proteins from the nitrogen-fixing actinomycete Frankia. The method was based on washing Frankia mycelia in 62.5 mM Tris–HCl (pH 6.8) buffer supplemented with 0.1% Triton X-100 as solubilizing agent. Cell wall-associated proteins were efficiently extracted in less than 10 min, recovering approximately 94.5±7.44 μg protein per extraction procedure from exponentially growing cells corresponding to 50 ml of culture. The amount of cell lysis occurring during the cell wall extraction was estimated to be 1.50±0.51%. Three peptidoglycan hydrolases with apparent molecular masses of 4.7, 12.1, and 17.8 kDa were detected by zymography in the cell wall-associated protein fraction. On the contrary, no cell wall lytic enzyme was detected in the cytoplasmic protein fraction. These results indicate that the present method enables a specific extraction of cell wall-associated proteins. Moreover, fluorescein isothiocyanate (FITC) labelling of the cell surface proteins showed an efficient removal of cell wall-associated proteins. Growth of the treated Frankia cells (i.e. cells from which the cell wall-associated proteins were removed) in semi-solid media suggested that these cells were still viable. This technique is of importance for functionality studies of cell wall-associated proteins, particularly for bacteria where traditional cell fractionation methods are difficult to be applied.

@article{astot_deuterium_2000,
	title = {Deuterium in vivo labelling of cytokinins in {Arabidopsis} thaliana analysed by capillary liquid chromatography/frit-fast atom bombardment mass spectrometry},
	volume = {35},
	issn = {1096-9888},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/%28SICI%291096-9888%28200001%2935%3A1%3C13%3A%3AAID-JMS901%3E3.0.CO%3B2-I},
	doi = {10.1002/(SICI)1096-9888(200001)35:1<13::AID-JMS901>3.0.CO;2-I},
	abstract = {A method was developed for analysing the biosynthetic rate of the cytokinin class of plant hormones. Transgenic, cytokinin-overproducing Arabidopsis thaliana plants were incubated in liquid culture media enriched with 30\% deuterium oxide, and incorporation into the different parts of the cytokinin molecule was analysed by capillary liquid chromatography/frit-fast atom bombardment mass spectrometry after precolumn propionylation. The sugar moieties of the cytokinins generally showed a high and independent incorporation, so the analysis in this study focused on the cytokinin base moieties. It was observed that during a 24 h incubation period almost all labelling was incorporated into the side-chain, rather than the adenine moiety. The incorporation dynamics of isopentenyladenosine-5′-monophosphate, zeatinriboside-5′-monophosphate (ZRMP) and zeatin-9-glucoside were investigated through analysis of the cytokinin base fragments in high-resolution selective ion monitoring mode. Using a fractional synthetic rate approach, the biosynthetic rate of ZRMP was determined to be 18 ng h−1 g−1 fresh weight, giving a turnover time of 25 h. A method for the mass isotopomer abundance analysis of the cytokinins in the zeatin family, based on selective reaction monitoring, was also developed to gain further sensitivity. Use of this technique showed that there was a higher level of enrichment in zeatin nucleotide than in the corresponding nucleoside, in agreement with the hypothesis that cytokinin nucleotides are primary products in this pathway. Copyright © 2000 John Wiley \& Sons, Ltd.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {Journal of Mass Spectrometry},
	author = {Åstot, Crister and Dolezal, Karel and Moritz, Thomas and Sandberg, Göran},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/\%28SICI\%291096-9888\%28200001\%2935\%3A1\%3C13\%3A\%3AAID-JMS901\%3E3.0.CO\%3B2-I},
	keywords = {Arabidopsis thaliana, cytokinin biosynthesis, fast atom bombardment, in vivo labelling, isotopomer},
	pages = {13--22},
}

A method was developed for analysing the biosynthetic rate of the cytokinin class of plant hormones. Transgenic, cytokinin-overproducing Arabidopsis thaliana plants were incubated in liquid culture media enriched with 30% deuterium oxide, and incorporation into the different parts of the cytokinin molecule was analysed by capillary liquid chromatography/frit-fast atom bombardment mass spectrometry after precolumn propionylation. The sugar moieties of the cytokinins generally showed a high and independent incorporation, so the analysis in this study focused on the cytokinin base moieties. It was observed that during a 24 h incubation period almost all labelling was incorporated into the side-chain, rather than the adenine moiety. The incorporation dynamics of isopentenyladenosine-5′-monophosphate, zeatinriboside-5′-monophosphate (ZRMP) and zeatin-9-glucoside were investigated through analysis of the cytokinin base fragments in high-resolution selective ion monitoring mode. Using a fractional synthetic rate approach, the biosynthetic rate of ZRMP was determined to be 18 ng h−1 g−1 fresh weight, giving a turnover time of 25 h. A method for the mass isotopomer abundance analysis of the cytokinins in the zeatin family, based on selective reaction monitoring, was also developed to gain further sensitivity. Use of this technique showed that there was a higher level of enrichment in zeatin nucleotide than in the corresponding nucleoside, in agreement with the hypothesis that cytokinin nucleotides are primary products in this pathway. Copyright © 2000 John Wiley & Sons, Ltd.

@article{shi_low_2000,
	title = {The {Low} {Molecular} {Mass} {PsbW} {Protein} {Is} {Involved} in the {Stabilization} of the {Dimeric} {Photosystem} {II} {Complex} in {Arabidopsis} thaliana *},
	volume = {275},
	issn = {0021-9258},
	url = {https://www.sciencedirect.com/science/article/pii/S002192582088510X},
	doi = {10.1074/jbc.M006300200},
	abstract = {Arabidopsis thaliana plants have been transformed with an antisense gene to the psbW of photosystem II (PSII). Eight transgenic lines containing low levels ofpsbW mRNA have been obtained. Transgenic seedlings with low contents of PsbW protein (more than 96\% reduced) were selected by Western blotting and used for photosynthetic functional studies. There were no distinct differences in phenotype between the antisense and wild type plants during vegetative period under normal growth light intensities. However, a sucrose gradient separation of briefly solubilized thylakoid membranes revealed that no dimeric PSII supracomplex could be detected in the transgenic plants lacking the PsbW protein. Furthermore, analysis of isolated thylakoids demonstrated that the oxygen-evolving rate in antisense plants decreased by 50\% compared with the wild type. This was found to be due to up to 40\% of D1 and D2 reaction center proteins of PSII disappearing in the transgenic plants. The absence of the PsbW protein also altered the contents of other PSII proteins to differing extents. These results show that in the absence of the PsbW protein, the stability of the dimeric PSII is diminished and consequently the total number of PSII complexes is greatly reduced. Thus the nuclear encoded PsbW protein may play a crucial role in the biogenesis and regulation of the photosynthetic apparatus.},
	language = {en},
	number = {48},
	urldate = {2021-11-08},
	journal = {Journal of Biological Chemistry},
	author = {Shi, Lan-Xin and Lorković, Zdravko J. and Oelmüller, Ralf and Schröder, Wolfgang P.},
	month = dec,
	year = {2000},
	pages = {37945--37950},
}

Arabidopsis thaliana plants have been transformed with an antisense gene to the psbW of photosystem II (PSII). Eight transgenic lines containing low levels ofpsbW mRNA have been obtained. Transgenic seedlings with low contents of PsbW protein (more than 96% reduced) were selected by Western blotting and used for photosynthetic functional studies. There were no distinct differences in phenotype between the antisense and wild type plants during vegetative period under normal growth light intensities. However, a sucrose gradient separation of briefly solubilized thylakoid membranes revealed that no dimeric PSII supracomplex could be detected in the transgenic plants lacking the PsbW protein. Furthermore, analysis of isolated thylakoids demonstrated that the oxygen-evolving rate in antisense plants decreased by 50% compared with the wild type. This was found to be due to up to 40% of D1 and D2 reaction center proteins of PSII disappearing in the transgenic plants. The absence of the PsbW protein also altered the contents of other PSII proteins to differing extents. These results show that in the absence of the PsbW protein, the stability of the dimeric PSII is diminished and consequently the total number of PSII complexes is greatly reduced. Thus the nuclear encoded PsbW protein may play a crucial role in the biogenesis and regulation of the photosynthetic apparatus.

@article{quinn_coordinate_2000,
	title = {Coordinate {Copper}- and {Oxygen}-responsive {Cyc6} {andCpx1} {Expression} in {Chlamydomonas} {Is} {Mediated} by the {Same} {Element}*},
	volume = {275},
	issn = {0021-9258},
	url = {https://www.sciencedirect.com/science/article/pii/S0021925818304551},
	doi = {10.1074/jbc.275.9.6080},
	abstract = {Chlamydomonas reinhardtii activates the transcription of the Cyc6 and the Cpx1genes (encoding cytochrome c6 and coprogen oxidase) in response to copper deficiency. Mutational analysis of promoter regions of the Cyc6 and Cpx1 genes revealed a four nucleotide sequence, GTAC, which was absolutely essential for copper responsiveness. The Cyc6 promoter contains two copper response elements, each with a functionally important GTAC sequence, whereas the Cpx1 promoter contains only one. This may contribute to the stronger and more tightly regulated expression of the Cyc6 gene. Mutation or deletion of sequences flanking the GTACs implicates additional nucleotides contributing to copper-responsive expression, but none are absolutely essential. Metal ion selectivity of Cpx1 expression is identical to that described previously for Cyc6 and is restricted to the copper deficiency-induced Cpx1transcript. The Cyc6 and Cpx1 genes are also induced by oxygen deficiency. Reporter gene constructs indicate that the induction occurs at the level of transcription and requires the same GTAC sequence that is critical for copper responsiveness. We suggest that components of the copper-responsive signal transduction pathway are used for some of the changes in gene expression in hypoxic cells.},
	language = {en},
	number = {9},
	urldate = {2021-11-08},
	journal = {Journal of Biological Chemistry},
	author = {Quinn, Jeanette M. and Barraco, Paola and Eriksson, Mats and Merchant, Sabeeha},
	month = mar,
	year = {2000},
	pages = {6080--6089},
}

Chlamydomonas reinhardtii activates the transcription of the Cyc6 and the Cpx1genes (encoding cytochrome c6 and coprogen oxidase) in response to copper deficiency. Mutational analysis of promoter regions of the Cyc6 and Cpx1 genes revealed a four nucleotide sequence, GTAC, which was absolutely essential for copper responsiveness. The Cyc6 promoter contains two copper response elements, each with a functionally important GTAC sequence, whereas the Cpx1 promoter contains only one. This may contribute to the stronger and more tightly regulated expression of the Cyc6 gene. Mutation or deletion of sequences flanking the GTACs implicates additional nucleotides contributing to copper-responsive expression, but none are absolutely essential. Metal ion selectivity of Cpx1 expression is identical to that described previously for Cyc6 and is restricted to the copper deficiency-induced Cpx1transcript. The Cyc6 and Cpx1 genes are also induced by oxygen deficiency. Reporter gene constructs indicate that the induction occurs at the level of transcription and requires the same GTAC sequence that is critical for copper responsiveness. We suggest that components of the copper-responsive signal transduction pathway are used for some of the changes in gene expression in hypoxic cells.

@article{karpinska_antagonistic_2000,
	title = {Antagonistic {Effects} of {Hydrogen} {Peroxide} and {Glutathione} on {Acclimation} to {Excess} {Excitation} {Energy} in {Arabidopsis}},
	volume = {50},
	issn = {1521-6551},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1080/15216540050176548},
	doi = {10.1080/15216540050176548},
	abstract = {The redox status of the quinone B (QB) and plastoquinone (PQ) pools plays a key role in the cellular and systemic signalling processes that control acclimatory responses in plants. In this study, we demonstrate the effects of hydrogen peroxide and glutathione on acclimatory responses controlled by redox events in the proximity of the QB-PQ pools. Our results suggest that the chloroplast is a sink for H2O2 and that, paradoxically, high concentrations of H2O2 in the chloroplast protect the photosynthetic apparatus and the plant cell from photoinhibition and photooxidative damage. Excess glutathione, however, caused an effect antagonistic to that observed for high H2O2. An explanation of this apparent paradox and a hypothetical redox-signalling model are suggested.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {IUBMB Life},
	author = {Karpinska, Barbara and Wingsle, Gunnar and Karpinski, Stanislaw},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1080/15216540050176548},
	keywords = {Arabidopsis, Ascorbate, Glutathe, Hydrogen, Ii, Oxidative, Peroxidase, Peroxide, Photoinhibition, Photosynthesis, Photosystem, Plastoquinone, Redox, Signalling., Stress, Thaliana, Thione},
	pages = {21--26},
}

The redox status of the quinone B (QB) and plastoquinone (PQ) pools plays a key role in the cellular and systemic signalling processes that control acclimatory responses in plants. In this study, we demonstrate the effects of hydrogen peroxide and glutathione on acclimatory responses controlled by redox events in the proximity of the QB-PQ pools. Our results suggest that the chloroplast is a sink for H2O2 and that, paradoxically, high concentrations of H2O2 in the chloroplast protect the photosynthetic apparatus and the plant cell from photoinhibition and photooxidative damage. Excess glutathione, however, caused an effect antagonistic to that observed for high H2O2. An explanation of this apparent paradox and a hypothetical redox-signalling model are suggested.

@article{schrick_fackel_2000,
	title = {{FACKEL} is a sterol {C}-14 reductase required for organized cell division and expansion in {Arabidopsis} embryogenesis},
	volume = {14},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC316688/},
	abstract = {In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. ...},
	language = {en},
	number = {12},
	urldate = {2021-11-08},
	journal = {Genes \& Development},
	author = {Schrick, Kathrin and Mayer, Ulrike and Horrichs, Andrea and Kuhnt, Christine and Bellini, Catherine and Dangl, Jeff and Schmidt, Jürgen and Jürgens, Gerd},
	month = jun,
	year = {2000},
	pmid = {10859166},
	note = {Publisher: Cold Spring Harbor Laboratory Press},
	pages = {1471},
}

In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. ...

@article{mahonen_novel_2000,
	title = {A novel two-component hybrid molecule regulates vascular morphogenesis of the {Arabidopsis} root},
	volume = {14},
	issn = {0890-9369, 1549-5477},
	url = {http://genesdev.cshlp.org/content/14/23/2938},
	doi = {10.1101/gad.189200},
	abstract = {The developmental ontogeny of the vascular system (consisting of xylem, phloem and [pro]cambium) is poorly understood despite its central role in plant physiology. We show that in theArabidopsis root meristem, xylem cell lineages are specified early, whereas phloem and procambium are established through a set of asymmetric cell divisions. These divisions require the WOODEN LEG (WOL) gene. The WOL gene encodes a novel two-component signal transducer with an unusual tandem arrangement of two receiver domains. It is expressed specifically in the vasculature from the early stages of embryogenesis on, consistent with a role as a sensor for vascular morphogenesis.},
	language = {en},
	number = {23},
	urldate = {2021-11-08},
	journal = {Genes \& Development},
	author = {Mähönen, Ari Pekka and Bonke, Martin and Kauppinen, Leila and Riikonen, Marjukka and Benfey, Philip N. and Helariutta, Ykä},
	month = dec,
	year = {2000},
	pmid = {11114883},
	note = {Company: Cold Spring Harbor Laboratory Press
Distributor: Cold Spring Harbor Laboratory Press
Institution: Cold Spring Harbor Laboratory Press
Label: Cold Spring Harbor Laboratory Press
Publisher: Cold Spring Harbor Lab},
	keywords = {DhkA, WOODEN LEG, asymmetric division, embryogenesis, procambium},
	pages = {2938--2943},
}

The developmental ontogeny of the vascular system (consisting of xylem, phloem and [pro]cambium) is poorly understood despite its central role in plant physiology. We show that in theArabidopsis root meristem, xylem cell lineages are specified early, whereas phloem and procambium are established through a set of asymmetric cell divisions. These divisions require the WOODEN LEG (WOL) gene. The WOL gene encodes a novel two-component signal transducer with an unusual tandem arrangement of two receiver domains. It is expressed specifically in the vasculature from the early stages of embryogenesis on, consistent with a role as a sensor for vascular morphogenesis.

@article{hakulinen_variation_2000,
	title = {Variation in leaf phenolics of field-cultivated willow ({Salix} myrsinifolia) clones in relation to occurrence of {Melampsora} rust},
	volume = {30},
	issn = {1439-0329},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1439-0329.2000.00184.x},
	doi = {10.1046/j.1439-0329.2000.00184.x},
	abstract = {Concentrations of potential antifungal phenolics in field-cultivated willow (Salix myrsinifolia) clones were analysed during three growing seasons, and correlated to the occurrence of Melampsora rust. Consistent relationships between phenolics and rust were not found across the experimental years. There was significant clonal and temporal variation in phenolic content and rust frequency. Levels of some phenolics varied considerably within a sequence of four full-grown leaves, but the variation in rust occurrence within the same leaf sequence was nonsignificant. The results suggest that the possible association between willow phenolics and rusts is not straightforward, and emphasize the importance of long-term studies to investigate the chemical basis of willow rust interactions.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {Forest Pathology},
	author = {Hakulinen, J. and Julkunen-Tiitto, R.},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1439-0329.2000.00184.x},
	pages = {29--41},
}

Concentrations of potential antifungal phenolics in field-cultivated willow (Salix myrsinifolia) clones were analysed during three growing seasons, and correlated to the occurrence of Melampsora rust. Consistent relationships between phenolics and rust were not found across the experimental years. There was significant clonal and temporal variation in phenolic content and rust frequency. Levels of some phenolics varied considerably within a sequence of four full-grown leaves, but the variation in rust occurrence within the same leaf sequence was nonsignificant. The results suggest that the possible association between willow phenolics and rusts is not straightforward, and emphasize the importance of long-term studies to investigate the chemical basis of willow rust interactions.

@article{kieselbach_peroxidase_2000,
	title = {A peroxidase homologue and novel plastocyanin located by proteomics to the {Arabidopsis} chloroplast thylakoid lumen},
	volume = {480},
	copyright = {FEBS Letters 480 (2000) 1873-3468 © 2015 Federation of European Biochemical Societies},
	issn = {1873-3468},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1016/S0014-5793%2800%2901890-1},
	doi = {10.1016/S0014-5793(00)01890-1},
	abstract = {A study by two-dimensional electrophoresis showed that the soluble, lumenal fraction of Arabidopsis thaliana thylakoids can be resolved into 300 protein spots. After subtraction of low-intensity spots and accounting for low-level stromal contamination, the number of more abundant, lumenal proteins was estimated to be between 30 and 60. Two of these proteins have been identified: a novel plastocyanin that also was the predominant component of the total plastocyanin pool, and a putative ascorbate peroxidase. Import studies showed that these proteins are routed to the thylakoid lumen by the Sec- and delta pH-dependent translocation pathways, respectively. In addition, novel isoforms of PsbO and PsbQ were identified.},
	language = {en},
	number = {2-3},
	urldate = {2021-11-08},
	journal = {FEBS Letters},
	author = {Kieselbach, Thomas and Bystedt, Maria and Hynds, Peter and Robinson, Colin and Schröder, Wolfgang P.},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793\%2800\%2901890-1},
	keywords = {AC, MALDI-TOF-MS, Oxygen evolution, Photosystem II, Protein import, SDS–PAGE, Twin-arginine translocase, accession number, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, pH translocation pathway, sodium dodecyl sulfate–polyacrylamide gel electrophoresis},
	pages = {271--276},
}

A study by two-dimensional electrophoresis showed that the soluble, lumenal fraction of Arabidopsis thaliana thylakoids can be resolved into 300 protein spots. After subtraction of low-intensity spots and accounting for low-level stromal contamination, the number of more abundant, lumenal proteins was estimated to be between 30 and 60. Two of these proteins have been identified: a novel plastocyanin that also was the predominant component of the total plastocyanin pool, and a putative ascorbate peroxidase. Import studies showed that these proteins are routed to the thylakoid lumen by the Sec- and delta pH-dependent translocation pathways, respectively. In addition, novel isoforms of PsbO and PsbQ were identified.

@article{ivanov_iron_2000,
	title = {Iron stress restricts photosynthetic intersystem electron transport in {Synechococcus} sp. {PCC} 7942},
	volume = {485},
	copyright = {FEBS Letters 485 (2000) 1873-3468 © 2015 Federation of European Biochemical Societies},
	issn = {1873-3468},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1016/S0014-5793%2800%2902211-0},
	doi = {10.1016/S0014-5793(00)02211-0},
	abstract = {Although exposure of Synechococcus sp. PCC 7942 to iron stress induced the accumulation of the isiA gene product (CP43′) compared with non-stressed controls, immunodetection of the N-terminus of cytochrome (Cyt) f indicated that iron stress not only reduced the content of the 40 kDa, heme-binding, Cyt f polypeptide by 32\% but it also specifically induced the accumulation of a new, 23 kDa, non-heme-binding, putative Cyt f polypeptide. Concomitantly, iron stress restricted intersystem electron transport based on the in vivo reduction of P700+, monitored as ΔA 820/A 820 in the presence and absence of electron transport inhibitors, as well as the inhibition of the Emerson enhancement effect on O2 evolution. However, iron stress appeared to be associated with enhanced rates of PS I cyclic electron transport, low rates of PS I-driven photoreduction of NADP+ but comparable rates for PS II+PS I photoreduction of NADP+ relative to controls. We hypothesize that Synechococcus sp. PCC 7942 exhibits a dynamic capacity to uncouple PS II and PS I electron transport, which may allow for the higher than expected growth rates observed during iron stress.},
	language = {en},
	number = {2-3},
	urldate = {2021-11-08},
	journal = {FEBS Letters},
	author = {Ivanov, A.g. and Park, Y.-I. and Miskiewicz, E. and Raven, J.a. and Huner, N.p.a. and Öquist, G.},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793\%2800\%2902211-0},
	keywords = {1-dimethylurea, 2, 3-(3, 3-N-morpholinopropanesulfonic acid, 4-dichlorophenyl)-1, 5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, 6-dichlorophenol-indophenol, Cyt, DBMIB, DCMU, DCPIP, Electron transport, FR, Iron stress, MOPS, MT, MV, P700, P700+, PC, PQ, PS I, PS II, Phc, Photosystem I, Pmax, ST, Synechococcus sp. PCC 7942, cytochrome, far red light, maximal photosynthetic oxygen evolution, methyl viologen, multiple turnover flash of actinic white light, oxidized form of the reaction center of PS I, photosystem I and photosystem II, phycocyanin, plastocyanin, plastoquinone, reaction center pigment of PS I, single turnover flash of actinic white light},
	pages = {173--177},
}

Although exposure of Synechococcus sp. PCC 7942 to iron stress induced the accumulation of the isiA gene product (CP43′) compared with non-stressed controls, immunodetection of the N-terminus of cytochrome (Cyt) f indicated that iron stress not only reduced the content of the 40 kDa, heme-binding, Cyt f polypeptide by 32% but it also specifically induced the accumulation of a new, 23 kDa, non-heme-binding, putative Cyt f polypeptide. Concomitantly, iron stress restricted intersystem electron transport based on the in vivo reduction of P700+, monitored as ΔA 820/A 820 in the presence and absence of electron transport inhibitors, as well as the inhibition of the Emerson enhancement effect on O2 evolution. However, iron stress appeared to be associated with enhanced rates of PS I cyclic electron transport, low rates of PS I-driven photoreduction of NADP+ but comparable rates for PS II+PS I photoreduction of NADP+ relative to controls. We hypothesize that Synechococcus sp. PCC 7942 exhibits a dynamic capacity to uncouple PS II and PS I electron transport, which may allow for the higher than expected growth rates observed during iron stress.

@article{ingvarsson_differential_2000,
	title = {Differential {Migration} from {High} {Fitness} {Demes} in the {Shining} {Fungus} {Beetle}, {Phalacrus} {Substriatus}},
	volume = {54},
	issn = {1558-5646},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0014-3820.2000.tb00031.x},
	doi = {10.1111/j.0014-3820.2000.tb00031.x},
	abstract = {Abstract.— Using data from three years (1994–1996), I tested whether differential migration occurs from demes of high mean fitness in the shining fungus beetle, Phalacrus substriatus. The results show evidence for differential migration, thus providing evidence from a natural population for a critical demographic assumption of many interdemic selection models. To predict the evolutionary response to interdemic selection through differential migration, the genetic basis of the variation among demes in mean fitness must be known because the observed patterns could also be explained by some demes having an intrinsically favorable habitat. Thus, the importance of differential migration through interdemic selection in natural populations cannot be unequivocally answered without experiments specifically addressing the question of what causes differences in mean fitness among demes.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {Evolution},
	author = {Ingvarsson, Pär K.},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.0014-3820.2000.tb00031.x},
	keywords = {Differential migration, Phalacrus substriatus, interdemic selection},
	pages = {297--301},
}

Abstract.— Using data from three years (1994–1996), I tested whether differential migration occurs from demes of high mean fitness in the shining fungus beetle, Phalacrus substriatus. The results show evidence for differential migration, thus providing evidence from a natural population for a critical demographic assumption of many interdemic selection models. To predict the evolutionary response to interdemic selection through differential migration, the genetic basis of the variation among demes in mean fitness must be known because the observed patterns could also be explained by some demes having an intrinsically favorable habitat. Thus, the importance of differential migration through interdemic selection in natural populations cannot be unequivocally answered without experiments specifically addressing the question of what causes differences in mean fitness among demes.

@article{rojdestvenski_two-dimensional_2000,
	title = {A two-dimensional many-body system with competing interactions as a model for segregation of photosystems in thylakoids of green plants},
	volume = {29},
	issn = {1432-1017},
	url = {https://doi.org/10.1007/s002490000080},
	doi = {10.1007/s002490000080},
	abstract = {We address the segregation of photosystems I (PSI) and II (PSII) in thylakoid membranes by means of a molecular dynamics method. We assume a two-dimensional (in-plane) problem with PSI and PSII being represented by particles with different values of negative charge. The pair interactions between particles include a screened Coulomb repulsive part and am exponentially decaying attractive part. Our modeling results suggest that the system may have a complicated phase behavior, including a quasi-crystalline phase at low ionic screening, a disordered phase and, in addition, a possible “clotting” agglomerate phase at high screening where the photosystems tend to clot together. The relevance of the observed phenomena to the stacking of thylakoid membranes is discussed.},
	language = {en},
	number = {3},
	urldate = {2021-11-08},
	journal = {European Biophysics Journal},
	author = {Rojdestvenski, I. and Ivanov, A. G. and Cottam, M. G. and Oquist, G.},
	month = jun,
	year = {2000},
	pages = {214--220},
}

We address the segregation of photosystems I (PSI) and II (PSII) in thylakoid membranes by means of a molecular dynamics method. We assume a two-dimensional (in-plane) problem with PSI and PSII being represented by particles with different values of negative charge. The pair interactions between particles include a screened Coulomb repulsive part and am exponentially decaying attractive part. Our modeling results suggest that the system may have a complicated phase behavior, including a quasi-crystalline phase at low ionic screening, a disordered phase and, in addition, a possible “clotting” agglomerate phase at high screening where the photosystems tend to clot together. The relevance of the observed phenomena to the stacking of thylakoid membranes is discussed.

@article{nordin_amino_2000,
	title = {Amino acid accumulation and growth of {Sphagnum} under different levels of {N} deposition},
	volume = {7},
	issn = {1195-6860},
	url = {https://doi.org/10.1080/11956860.2000.11682619},
	doi = {10.1080/11956860.2000.11682619},
	abstract = {Nitrogen (N) is a critical nutrient for Sphagnum mosses dominating mire ecosystems. We simulated N deposition by adding doses of NH4NO3 (0, 1, 3, 5 and 10 g m−2 yr−1) to two Swedish mires with different levels of background atmospheric N deposition, i.e., on Luttumyren in central Sweden 0.3-0.4 g N m−2 yr−1 and 0.7-1.1 g N m−2 yr−1 on Åkhultmyren in south Sweden. After two years of NH4NO3 additions, free amino acid concentrations of S. fuscum, S. magellanicum and S. rubellum from the two mires were analyzed and length growth of the mosses were measured. N additions increased amino acid concentrations in Sphagnum capitula, whereas it decreased Sphagnum length growth. In general, we found that when Sphagnum amino acid N concentrations exceeded 2.0 mg amino acid N g−1 dry mass, Sphagnum length growth was reduced. The decreased growth did not explain the variation in amino acid concentrations. Hence, increased Sphagnum N assimilation in N treated plots was most likely the factor causing tissue amino acid concentrations to increase. Significant differences among control plots between the two mires in Sphagnum total amino acid N concentrations did not occur. Total amino acid N concentrations of Sphagnum are thus not sensitive enough to reflect differences in N deposition rates when they are below 1.0 g m−2 yr−1.},
	number = {4},
	urldate = {2021-11-08},
	journal = {Écoscience},
	author = {Nordin, Annika and Gunnarsson, Urban},
	month = jan,
	year = {2000},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/11956860.2000.11682619},
	keywords = {Acides aminés, Amino acids, Croissance, Déposition atmosphérique azotée, Growth, N deposition, Sphagnum, Sphaigne},
	pages = {474--480},
}

Nitrogen (N) is a critical nutrient for Sphagnum mosses dominating mire ecosystems. We simulated N deposition by adding doses of NH4NO3 (0, 1, 3, 5 and 10 g m−2 yr−1) to two Swedish mires with different levels of background atmospheric N deposition, i.e., on Luttumyren in central Sweden 0.3-0.4 g N m−2 yr−1 and 0.7-1.1 g N m−2 yr−1 on Åkhultmyren in south Sweden. After two years of NH4NO3 additions, free amino acid concentrations of S. fuscum, S. magellanicum and S. rubellum from the two mires were analyzed and length growth of the mosses were measured. N additions increased amino acid concentrations in Sphagnum capitula, whereas it decreased Sphagnum length growth. In general, we found that when Sphagnum amino acid N concentrations exceeded 2.0 mg amino acid N g−1 dry mass, Sphagnum length growth was reduced. The decreased growth did not explain the variation in amino acid concentrations. Hence, increased Sphagnum N assimilation in N treated plots was most likely the factor causing tissue amino acid concentrations to increase. Significant differences among control plots between the two mires in Sphagnum total amino acid N concentrations did not occur. Total amino acid N concentrations of Sphagnum are thus not sensitive enough to reflect differences in N deposition rates when they are below 1.0 g m−2 yr−1.

@article{riber_albrectsen_flowering_2000,
	title = {Flowering phenology and seed predation by a tephritid fly: {Escape} of seeds in time and space},
	volume = {7},
	issn = {1195-6860},
	shorttitle = {Flowering phenology and seed predation by a tephritid fly},
	url = {https://doi.org/10.1080/11956860.2000.11682614},
	doi = {10.1080/11956860.2000.11682614},
	abstract = {Seed predators, like pollinators, may potentially act as a selective force on flowering phenology. Attack patterns by the specialist tephritid fly Paroxyna plantaginis (Diptera) were studied at the northern distribution limit of its monocarpic host plant Tripolium vulgare (Asteraceae), which is characterized by an extended flowering period. Plants were successfully transplanted onto eight islands and removed successively throughout the season in order to follow the temporal and spatial variation in attack risk. The results were compared to patterns found in eleven natural populations. Early (terminal) flower heads had higher potential seed set and were less prone to attack by P. plantaginis in a year with normal high attack rates and under normal weather conditions. The attack to terminal flower heads followed the overall attack risk at the plant level. The density of ovipositing females early in the season was the most likely explanation for the attack pattern. This suggests a phenological lag between the first flowering heads and the emergence of seed predators, which may break down at high fly densities. Spatial and stochastic factors affected fly density, which may confuse the selective force.},
	number = {4},
	urldate = {2021-11-08},
	journal = {Écoscience},
	author = {Riber Albrectsen, Benedicte},
	month = jan,
	year = {2000},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/11956860.2000.11682614},
	keywords = {Avoidance strategies, Interaction plante-animal, Paroxyna plantaginis (Diptera, Tephritidae), Plant-animal interaction, Pre-dispersal seed predation, Prédation de graines non dispersées, Stratégies d’évitement, Tripolium vulgare (Aster tripolium, Asteraceae)},
	pages = {433--438},
}

Seed predators, like pollinators, may potentially act as a selective force on flowering phenology. Attack patterns by the specialist tephritid fly Paroxyna plantaginis (Diptera) were studied at the northern distribution limit of its monocarpic host plant Tripolium vulgare (Asteraceae), which is characterized by an extended flowering period. Plants were successfully transplanted onto eight islands and removed successively throughout the season in order to follow the temporal and spatial variation in attack risk. The results were compared to patterns found in eleven natural populations. Early (terminal) flower heads had higher potential seed set and were less prone to attack by P. plantaginis in a year with normal high attack rates and under normal weather conditions. The attack to terminal flower heads followed the overall attack risk at the plant level. The density of ovipositing females early in the season was the most likely explanation for the attack pattern. This suggests a phenological lag between the first flowering heads and the emergence of seed predators, which may break down at high fly densities. Spatial and stochastic factors affected fly density, which may confuse the selective force.

@article{sjoberg_truncated_2000,
	title = {Truncated power laws: a tool for understanding aggregation patterns in animals?},
	volume = {3},
	issn = {1461-0248},
	shorttitle = {Truncated power laws},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1461-0248.2000.00113.x},
	doi = {10.1046/j.1461-0248.2000.00113.x},
	abstract = {Statistical distributions like the negative binomial distribution are commonly used to describe aggregation patterns in animals. However, recently it has been suggested that truncated power laws (TPLs) may also be used for this kind of analysis. A TPL consists of two power functions separated by a cut-off size (C*). The cut-off size and the slope of power function one (β1) for the smallest group sizes have been suggested to have a biological explanatory value. We applied TPLs to aggregation data of tephritid seed predators on a composite plant, aphids on willows and grey seals on a haulout site. β1 varied between 0.60 and and −0.72, which is higher than predicted. In addition, resource distribution and animal density influenced β1 and C*. This indicates that environmental dimensionality suggested to affect β1 is masked by ecological factors. We conclude that TPLs are useful due to their simplicity and, in comparison with traditional methods, provide additional biologically relevant information. Truncated power laws can therefore prove to be useful in studies of animal behaviour and population dynamics.},
	language = {en},
	number = {2},
	urldate = {2021-11-08},
	journal = {Ecology Letters},
	author = {Sjöberg, Mikael and Albrectsen, Benedicte and Hjältén, Joakim},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1461-0248.2000.00113.x},
	keywords = {Aggregation patterns, frequency distribution, group size, truncated power law},
	pages = {90--94},
}

Statistical distributions like the negative binomial distribution are commonly used to describe aggregation patterns in animals. However, recently it has been suggested that truncated power laws (TPLs) may also be used for this kind of analysis. A TPL consists of two power functions separated by a cut-off size (C*). The cut-off size and the slope of power function one (β1) for the smallest group sizes have been suggested to have a biological explanatory value. We applied TPLs to aggregation data of tephritid seed predators on a composite plant, aphids on willows and grey seals on a haulout site. β1 varied between 0.60 and and −0.72, which is higher than predicted. In addition, resource distribution and animal density influenced β1 and C*. This indicates that environmental dimensionality suggested to affect β1 is masked by ecological factors. We conclude that TPLs are useful due to their simplicity and, in comparison with traditional methods, provide additional biologically relevant information. Truncated power laws can therefore prove to be useful in studies of animal behaviour and population dynamics.

@article{nasholm_uptake_2000,
	title = {Uptake of {Organic} {Nitrogen} in the {Field} by {Four} {Agriculturally} {Important} {Plant} {Species}},
	volume = {81},
	issn = {1939-9170},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1890/0012-9658%282000%29081%5B1155%3AUOONIT%5D2.0.CO%3B2},
	doi = {10.1890/0012-9658(2000)081[1155:UOONIT]2.0.CO;2},
	abstract = {Uptake of glycine was studied in four plants commonly used in grasslands in northern Europe (Phleum pratense, Trifolium hybridum, T. pratense, and Ranunculus acris) and compared to uptake of ammonium and nitrate. The experiment was conducted in the field, but with plants transferred to pots with soil 8–10 d before the start of the experiment. Plant uptake of U-13C215N glycine, 15NH4+, and 15NO3− was studied by injecting dilute (1 mmol/L) solutions of respectively labeled N source into the pots and harvesting plants 21 h later. Measurements of 13C and 15N in roots showed that, in all plants, part of the glycine N was taken up in the form of intact amino acid. Hence, regressions of plots of excess 13C against excess 15N showed that a minimum of 19–23\% of the glycine-derived N was taken up as intact amino acid; possible losses of labeled C atoms of glycine during its metabolism in the plants implies that these estimates are conservative. Uptake of the different N sources was similar in the two Trifolium species, while rates of nitrate uptake were comparably high in P. pratense, and rates of glycine uptake were comparably low in R. acris. 15N labeling of shoots was detected in all species, whereas significant levels of 13C tracer was only found in shoots of P. pratense. It is concluded that a capacity for uptake of organic N exists also in an agricultural setting, despite the rapid turnover of organic N usually found under such conditions. This adds to the growing knowledge of plant utilization of organic N sources in natural ecosystems and stresses the need for reexamining this step in the biogeochemical N cycle.},
	language = {en},
	number = {4},
	urldate = {2021-11-08},
	journal = {Ecology},
	author = {Näsholm, Torgny and Huss-Danell, Kerstin and Högberg, Peter},
	year = {2000},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1890/0012-9658\%282000\%29081\%5B1155\%3AUOONIT\%5D2.0.CO\%3B2},
	keywords = {15N and 13C, Phleum pratense, Ranunculus acris, Trifolium hybridum, Trifolium pratense., agricultural plants, amino acid, ammonium, glycine, nitrate, organic nitrogen uptake, stable isotopes},
	pages = {1155--1161},
}

Uptake of glycine was studied in four plants commonly used in grasslands in northern Europe (Phleum pratense, Trifolium hybridum, T. pratense, and Ranunculus acris) and compared to uptake of ammonium and nitrate. The experiment was conducted in the field, but with plants transferred to pots with soil 8–10 d before the start of the experiment. Plant uptake of U-13C215N glycine, 15NH4+, and 15NO3− was studied by injecting dilute (1 mmol/L) solutions of respectively labeled N source into the pots and harvesting plants 21 h later. Measurements of 13C and 15N in roots showed that, in all plants, part of the glycine N was taken up in the form of intact amino acid. Hence, regressions of plots of excess 13C against excess 15N showed that a minimum of 19–23% of the glycine-derived N was taken up as intact amino acid; possible losses of labeled C atoms of glycine during its metabolism in the plants implies that these estimates are conservative. Uptake of the different N sources was similar in the two Trifolium species, while rates of nitrate uptake were comparably high in P. pratense, and rates of glycine uptake were comparably low in R. acris. 15N labeling of shoots was detected in all species, whereas significant levels of 13C tracer was only found in shoots of P. pratense. It is concluded that a capacity for uptake of organic N exists also in an agricultural setting, despite the rapid turnover of organic N usually found under such conditions. This adds to the growing knowledge of plant utilization of organic N sources in natural ecosystems and stresses the need for reexamining this step in the biogeochemical N cycle.

@article{wysocka-diller_molecular_2000,
	title = {Molecular analysis of {SCARECROW} function reveals a radial patterning mechanism common to root and shoot},
	volume = {127},
	issn = {0950-1991},
	url = {https://doi.org/10.1242/dev.127.3.595},
	doi = {10.1242/dev.127.3.595},
	abstract = {Mutation of the SCARECROW (SCR) gene results in a radial pattern defect, loss of a ground tissue layer, in the root. Analysis of the shoot phenotype of scr mutants revealed that both hypocotyl and shoot inflorescence also have a radial pattern defect, loss of a normal starch sheath layer, and consequently are unable to sense gravity in the shoot. Analogous to its expression in the endodermis of the root, SCR is expressed in the starch sheath of the hypocotyl and inflorescence stem. The SCR expression pattern in leaf bundle sheath cells and root quiescent center cells led to the identification of additional phenotypic defects in these tissues. SCR expression in a pin-formed mutant background suggested the possible origins of the starch sheath in the shoot inflorescence. Analysis of SCR expression and the mutant phenotype from the earliest stages of embryogenesis revealed a tight correlation between defective cell divisions and SCR expression in cells that contribute to ground tissue radial patterning in both embryonic root and shoot. Our data provides evidence that the same molecular mechanism regulates the radial patterning of ground tissue in both root and shoot during embryogenesis as well as postembryonically.},
	number = {3},
	urldate = {2021-11-08},
	journal = {Development},
	author = {Wysocka-Diller, J.W. and Helariutta, Y. and Fukaki, H. and Malamy, J.E. and Benfey, P.N.},
	month = feb,
	year = {2000},
	pages = {595--603},
}

Mutation of the SCARECROW (SCR) gene results in a radial pattern defect, loss of a ground tissue layer, in the root. Analysis of the shoot phenotype of scr mutants revealed that both hypocotyl and shoot inflorescence also have a radial pattern defect, loss of a normal starch sheath layer, and consequently are unable to sense gravity in the shoot. Analogous to its expression in the endodermis of the root, SCR is expressed in the starch sheath of the hypocotyl and inflorescence stem. The SCR expression pattern in leaf bundle sheath cells and root quiescent center cells led to the identification of additional phenotypic defects in these tissues. SCR expression in a pin-formed mutant background suggested the possible origins of the starch sheath in the shoot inflorescence. Analysis of SCR expression and the mutant phenotype from the earliest stages of embryogenesis revealed a tight correlation between defective cell divisions and SCR expression in cells that contribute to ground tissue radial patterning in both embryonic root and shoot. Our data provides evidence that the same molecular mechanism regulates the radial patterning of ground tissue in both root and shoot during embryogenesis as well as postembryonically.

@article{helariutta_short-root_2000,
	title = {The {SHORT}-{ROOT} {Gene} {Controls} {Radial} {Patterning} of the {Arabidopsis} {Root} through {Radial} {Signaling}},
	volume = {101},
	issn = {0092-8674},
	url = {https://www.sciencedirect.com/science/article/pii/S009286740080865X},
	doi = {10.1016/S0092-8674(00)80865-X},
	abstract = {Asymmetric cell divisions play an important role in the establishment and propagation of the cellular pattern of plant tissues. The SHORT-ROOT (SHR) gene is required for the asymmetric cell division responsible for formation of ground tissue (endodermis and cortex) as well as specification of endodermis in the Arabidopsis root. We show that SHR encodes a putative transcription factor with homology to SCARECROW (SCR). From analyses of gene expression and cell identity in genetically stable and unstable alleles of shr, we conclude that SHR functions upstream of SCR and participates in a radial signaling pathway. Consistent with a regulatory role in radial patterning, ectopic expression of SHR results in supernumerary cell divisions and abnormal cell specification in the root meristem.},
	language = {en},
	number = {5},
	urldate = {2021-11-08},
	journal = {Cell},
	author = {Helariutta, Yrjo and Fukaki, Hidehiro and Wysocka-Diller, Joanna and Nakajima, Keiji and Jung, Jee and Sena, Giovanni and Hauser, Marie-Theres and Benfey, Philip N},
	month = may,
	year = {2000},
	pages = {555--567},
}

Asymmetric cell divisions play an important role in the establishment and propagation of the cellular pattern of plant tissues. The SHORT-ROOT (SHR) gene is required for the asymmetric cell division responsible for formation of ground tissue (endodermis and cortex) as well as specification of endodermis in the Arabidopsis root. We show that SHR encodes a putative transcription factor with homology to SCARECROW (SCR). From analyses of gene expression and cell identity in genetically stable and unstable alleles of shr, we conclude that SHR functions upstream of SCR and participates in a radial signaling pathway. Consistent with a regulatory role in radial patterning, ectopic expression of SHR results in supernumerary cell divisions and abnormal cell specification in the root meristem.

@article{ruotsalainen_formulas_2000,
	title = {Some formulas concerned with pollen contamination have constrained use in {Lindgren} and {Mullin} (1998). {Relatedness} and status number in seed orchard crops},
	volume = {30},
	issn = {0045-5067},
	url = {https://cdnsciencepub.com/doi/10.1139/x99-209},
	doi = {10.1139/x99-209},
	abstract = {A recent paper by Lindgren and Mullin (1998) investigated relatedness and status effective number of seed orchard crops, collected under a variety of circumstances. We have determined that there is an error in the paper. An attempt was made in eqs. 8 and 9 to derive average relatedness of the gene pool of the seed crop when the orchard is exposed to pollen contamination. Average relatedness is the probability that two genes from the seed crop are identical by descent. It was assumed (p. 279) that the male fertilities sum to 0.5 (the other half of the genes coming from the seed parents) for the term corresponding to the case when both genes considered originate from the seed orchard. This is not correct, and this also affects some developments based on these formulas. Relatedness, when the compared genes both originate from the seed orchard, can occur because both the genes share the same seed parent or because they share the same pollen parent. It will (usually) be more common that they share seed parent than that they share pollen parent following pollen contamination, and thus the female fertilities will receive more weight and the male less weight. If an additional assumption is made, being that the fertility on the male side is directly proportional to that on the female side, the formulas and conclusions will be correct. The relative share of contributions among the clones will then be independent of the contamination. In many cases, this assumption is a realistic approximation. Even when this assumption is not fulfilled, many of the conclusions may be correct or approximately correct.},
	number = {2},
	urldate = {2021-11-08},
	journal = {Canadian Journal of Forest Research},
	author = {Ruotsalainen, Seppo and Lindgren, Dag and Mullin, TJ},
	month = feb,
	year = {2000},
	note = {Publisher: NRC Research Press},
	pages = {333},
}

A recent paper by Lindgren and Mullin (1998) investigated relatedness and status effective number of seed orchard crops, collected under a variety of circumstances. We have determined that there is an error in the paper. An attempt was made in eqs. 8 and 9 to derive average relatedness of the gene pool of the seed crop when the orchard is exposed to pollen contamination. Average relatedness is the probability that two genes from the seed crop are identical by descent. It was assumed (p. 279) that the male fertilities sum to 0.5 (the other half of the genes coming from the seed parents) for the term corresponding to the case when both genes considered originate from the seed orchard. This is not correct, and this also affects some developments based on these formulas. Relatedness, when the compared genes both originate from the seed orchard, can occur because both the genes share the same seed parent or because they share the same pollen parent. It will (usually) be more common that they share seed parent than that they share pollen parent following pollen contamination, and thus the female fertilities will receive more weight and the male less weight. If an additional assumption is made, being that the fertility on the male side is directly proportional to that on the female side, the formulas and conclusions will be correct. The relative share of contributions among the clones will then be independent of the contamination. In many cases, this assumption is a realistic approximation. Even when this assumption is not fulfilled, many of the conclusions may be correct or approximately correct.

@article{ruotsalainen_stratified_2000,
	title = {Stratified sublining: a new option for structuring breeding populations},
	volume = {30},
	issn = {0045-5067},
	shorttitle = {Stratified sublining},
	url = {https://cdnsciencepub.com/doi/10.1139/x99-245},
	doi = {10.1139/x99-245},
	number = {4},
	urldate = {2021-11-08},
	journal = {Canadian Journal of Forest Research},
	author = {Ruotsalainen, Seppo and Lindgren, Dag},
	month = apr,
	year = {2000},
	note = {Publisher: NRC Research Press},
	pages = {596--604},
}

@article{fries_effect_2000,
	title = {The effect of temperature on site index in western {Canada} and {Scandinavia} estimated from {IUFRO} {Pinus} contorta provenance experiments},
	volume = {30},
	issn = {0045-5067},
	url = {https://cdnsciencepub.com/doi/10.1139/x00-029},
	doi = {10.1139/x00-029},
	number = {6},
	urldate = {2021-11-08},
	journal = {Canadian Journal of Forest Research},
	author = {Fries, Anders and Lindgren, Dag and Ying, Cheng C and Ruotsalainen, Seppo and Lindgren, Katarina and Elfving, Björn and Karlmats, Ulf},
	month = jun,
	year = {2000},
	note = {Publisher: NRC Research Press},
	pages = {921--929},
}

@article{fries_high_2000,
	title = {High heritability of wood extractives in {Pinus} sylvestris progeny tests},
	volume = {30},
	issn = {0045-5067},
	url = {https://cdnsciencepub.com/doi/10.1139/x00-100},
	doi = {10.1139/x00-100},
	number = {11},
	urldate = {2021-11-08},
	journal = {Canadian Journal of Forest Research},
	author = {Fries, Anders and Ericsson, Tore and Gref, Rolf},
	month = nov,
	year = {2000},
	note = {Publisher: NRC Research Press},
	pages = {1707--1713},
}

@article{mattsson_hydrogenase_2000,
	title = {Hydrogenase in {Frankia} {KB5}: {Expression} of and relation to nitrogenase},
	volume = {46},
	issn = {0008-4166},
	shorttitle = {Hydrogenase in {Frankia} {KB5}},
	url = {https://cdnsciencepub.com/doi/10.1139/w00-100},
	doi = {10.1139/w00-100},
	number = {12},
	urldate = {2021-11-08},
	journal = {Canadian Journal of Microbiology},
	author = {Mattsson, Ulrika and Sellstedt, Anita},
	month = dec,
	year = {2000},
	note = {Publisher: NRC Research Press},
	pages = {1091--1095},
}

@article{kleczkowski_is_2000,
	title = {Is leaf {ADP}-glucose pyrophosphorylase an allosteric enzyme?},
	volume = {1476},
	issn = {0167-4838},
	url = {https://www.sciencedirect.com/science/article/pii/S0167483899002290},
	doi = {10.1016/S0167-4838(99)00229-0},
	abstract = {Barley leaf ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch synthesis in the chloroplast stroma, was analysed, in both directions of the reaction, with respect to details of its regulation by 3-phosphoglycerate (PGA) and inorganic phosphate (Pi) which serve as activator and inhibitor, respectively. AGPase was found to catalyse a close-to-equilibrium reaction, with the Keq value of approximately 0.5, i.e. slightly favouring the pyrophosphorolytic direction. When the enzyme was analysed by substrate kinetics, PGA acted either as a linear (hyperbolic response) ‘non-competitive’ activator (forward reaction) or a linear near-‘competitive’ activator (reverse reaction). When the activation and inhibition patterns with PGA and Pi, respectively, were studied in detail by Dixon plots, the response curves to effectors also followed hyperbolic kinetics, with the experimentally determined Ka and Ki values on the order of micromolar. The results suggest that the regulation of AGPase proceeds via a non-cooperative mechanism, where neither of the effectors, when considered separately, induces any allosteric response. The evidence, discussed in terms of an overall kinetic mechanism/regulation of leaf AGPase, prompts caution in classifying the protein as an ‘allosteric enzyme’.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology},
	author = {Kleczkowski, Leszek A},
	month = jan,
	year = {2000},
	keywords = {Allosteric regulation, Cooperative kinetics, Starch synthesis},
	pages = {103--108},
}

Barley leaf ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch synthesis in the chloroplast stroma, was analysed, in both directions of the reaction, with respect to details of its regulation by 3-phosphoglycerate (PGA) and inorganic phosphate (Pi) which serve as activator and inhibitor, respectively. AGPase was found to catalyse a close-to-equilibrium reaction, with the Keq value of approximately 0.5, i.e. slightly favouring the pyrophosphorolytic direction. When the enzyme was analysed by substrate kinetics, PGA acted either as a linear (hyperbolic response) ‘non-competitive’ activator (forward reaction) or a linear near-‘competitive’ activator (reverse reaction). When the activation and inhibition patterns with PGA and Pi, respectively, were studied in detail by Dixon plots, the response curves to effectors also followed hyperbolic kinetics, with the experimentally determined Ka and Ki values on the order of micromolar. The results suggest that the regulation of AGPase proceeds via a non-cooperative mechanism, where neither of the effectors, when considered separately, induces any allosteric response. The evidence, discussed in terms of an overall kinetic mechanism/regulation of leaf AGPase, prompts caution in classifying the protein as an ‘allosteric enzyme’.

@article{swarup_auxin_2000,
	title = {Auxin transport: providing a sense of direction during plant development},
	volume = {28},
	issn = {0300-5127},
	shorttitle = {Auxin transport},
	url = {https://doi.org/10.1042/bst0280481},
	doi = {10.1042/bst0280481},
	abstract = {Auxins are key regulators of plant development. Plants employ a specialized delivery system termed polar auxin transport to convey indole-3-acetic acid from source to target tissues. Auxin transport is mediated by the combined activities of specialized influx and efflux carriers. Mutational approaches in the model plant, Arabidopsis thaliana, have led to the molecular genetic characterization of putative auxin influx and efflux carrier components, AUX1 and AtPIN1. Both genes belong to distinct gene families that are being functionally characterized by using a reverse genetic approach in Arabidopsis. AtPIN proteins are asymmetrically localized within plant plasma membranes, providing a molecular mechanism for the characteristic polarity of auxin transport. We outline the epitope tagging strategy being used in our laboratory to immunolocalize AUX1 and discuss the implications of its subcellular localization for auxin redistribution within root apical tissues. Lastly, we describe a novel carrier-based mechanism that plant cells might use to determine their relative position(s) within an auxin gradient, drawing parallels with the mechanism of glucose perception in yeast.},
	number = {4},
	urldate = {2021-11-08},
	journal = {Biochemical Society Transactions},
	author = {Swarup, R. and Marchant, A. and Bennett, M. J.},
	month = aug,
	year = {2000},
	pages = {481--485},
}

Auxins are key regulators of plant development. Plants employ a specialized delivery system termed polar auxin transport to convey indole-3-acetic acid from source to target tissues. Auxin transport is mediated by the combined activities of specialized influx and efflux carriers. Mutational approaches in the model plant, Arabidopsis thaliana, have led to the molecular genetic characterization of putative auxin influx and efflux carrier components, AUX1 and AtPIN1. Both genes belong to distinct gene families that are being functionally characterized by using a reverse genetic approach in Arabidopsis. AtPIN proteins are asymmetrically localized within plant plasma membranes, providing a molecular mechanism for the characteristic polarity of auxin transport. We outline the epitope tagging strategy being used in our laboratory to immunolocalize AUX1 and discuss the implications of its subcellular localization for auxin redistribution within root apical tissues. Lastly, we describe a novel carrier-based mechanism that plant cells might use to determine their relative position(s) within an auxin gradient, drawing parallels with the mechanism of glucose perception in yeast.

@article{artursson_study_2000,
	title = {Study of {Preprocessing} {Methods} for the {Determination} of {Crystalline} {Phases} in {Binary} {Mixtures} of {Drug} {Substances} by {X}-ray {Powder} {Diffraction} and {Multivariate} {Calibration}},
	volume = {54},
	issn = {0003-7028},
	url = {https://doi.org/10.1366/0003702001950805},
	doi = {10.1366/0003702001950805},
	abstract = {In this paper, various preprocessing methods were tested on data generated by X-ray powder diffraction (XRPD) in order to enhance the partial least-squares (PLS) regression modeling performance. The preprocessing methods examined were 22 different discrete wavelet transforms, Fourier transform, Savitzky–Golay, orthogonal signal correction (OSC), and combinations of wavelet transform and OSC, and Fourier transform and OSC. Root mean square error of prediction (RMSEP) of an independent test set was used to measure the performance of the various preprocessing methods. The best PLS model was obtained with a wavelet transform (Symmlet 8), which at the same time compressed the data set by a factor of 9.5. With the use of wavelet and X-ray powder diffraction, concentrations of less than 10\% of one crystal from could be detected in a binary mixture. The linear range was found to be in the range 10–70\% of the crystalline form of phenacetin, although semiquantitative work could be carried out down to a level of approximately 2\%. Furthermore, the wavelet-pretreated models were able to handle admixtures and deliberately added noise.},
	language = {en},
	number = {8},
	urldate = {2021-11-08},
	journal = {Applied Spectroscopy},
	author = {Artursson, Tom and Hagman, Anders and Björk, Seth and Trygg, Johan and Wold, Svante and Jacobsson, Sven P.},
	month = aug,
	year = {2000},
	note = {Publisher: SAGE Publications Ltd STM},
	keywords = {Fourier transform, Orthogonal signal correction, PLS, Pretreatment, Savitzky–Golay, Wavelet transform, XRPD},
	pages = {1222--1230},
}

In this paper, various preprocessing methods were tested on data generated by X-ray powder diffraction (XRPD) in order to enhance the partial least-squares (PLS) regression modeling performance. The preprocessing methods examined were 22 different discrete wavelet transforms, Fourier transform, Savitzky–Golay, orthogonal signal correction (OSC), and combinations of wavelet transform and OSC, and Fourier transform and OSC. Root mean square error of prediction (RMSEP) of an independent test set was used to measure the performance of the various preprocessing methods. The best PLS model was obtained with a wavelet transform (Symmlet 8), which at the same time compressed the data set by a factor of 9.5. With the use of wavelet and X-ray powder diffraction, concentrations of less than 10% of one crystal from could be detected in a binary mixture. The linear range was found to be in the range 10–70% of the crystalline form of phenacetin, although semiquantitative work could be carried out down to a level of approximately 2%. Furthermore, the wavelet-pretreated models were able to handle admixtures and deliberately added noise.

@article{eriksson_orthogonal_2000,
	title = {Orthogonal signal correction, wavelet analysis, and multivariate calibration of complicated process fluorescence data},
	volume = {420},
	issn = {0003-2670},
	url = {https://www.sciencedirect.com/science/article/pii/S0003267000008904},
	doi = {10.1016/S0003-2670(00)00890-4},
	abstract = {In this paper, multivariate calibration of complicated process fluorescence data is presented. Two data sets related to the production of white sugar are investigated. The first data set comprises 106 observations and 571 spectral variables, and the second data set 268 observations and 3997 spectral variables. In both applications, a single response, ash content, is modelled and predicted as a function of the spectral variables. Both data sets contain certain features making multivariate calibration efforts non-trivial. The objective is to show how principal component analysis (PCA) and partial least squares (PLS) regression can be used to overview the data sets and to establish predictively sound regression models. It is shown how a recently developed technique for signal filtering, orthogonal signal correction (OSC), can be applied in multivariate calibration to enhance predictive power. In addition, signal compression is tested on the larger data set using wavelet analysis. It is demonstrated that a compression down to 4\% of the original matrix size — in the variable direction — is possible without loss of predictive power. It is concluded that the combination of OSC for pre-processing and wavelet analysis for compression of spectral data is promising for future use.},
	language = {en},
	number = {2},
	urldate = {2021-11-08},
	journal = {Analytica Chimica Acta},
	author = {Eriksson, Lennart and Trygg, Johan and Johansson, Erik and Bro, Rasmus and Wold, Svante},
	month = sep,
	year = {2000},
	keywords = {Multivariate calibration, Orthogonal signal correction, Partial least squares projections to latent structures, Principal component analysis, Process fluorescence data, Wavelet analysis},
	pages = {181--195},
}

In this paper, multivariate calibration of complicated process fluorescence data is presented. Two data sets related to the production of white sugar are investigated. The first data set comprises 106 observations and 571 spectral variables, and the second data set 268 observations and 3997 spectral variables. In both applications, a single response, ash content, is modelled and predicted as a function of the spectral variables. Both data sets contain certain features making multivariate calibration efforts non-trivial. The objective is to show how principal component analysis (PCA) and partial least squares (PLS) regression can be used to overview the data sets and to establish predictively sound regression models. It is shown how a recently developed technique for signal filtering, orthogonal signal correction (OSC), can be applied in multivariate calibration to enhance predictive power. In addition, signal compression is tested on the larger data set using wavelet analysis. It is demonstrated that a compression down to 4% of the original matrix size — in the variable direction — is possible without loss of predictive power. It is concluded that the combination of OSC for pre-processing and wavelet analysis for compression of spectral data is promising for future use.

@article{wu_accounting_2000,
	title = {{ACCOUNTING} {FOR} {BREEDING} {VALUES}, {HETEROGENEOUS} {VARIANCES} {AND} {MATERNAL} {EFFECTS} {IN} {ESTIMATING} {SELFING} {DEPRESSION} {FOR} {INDIVIDUAL} {PEDIGREES}},
	volume = {7},
	abstract = {Inbreeding depression (ID) has been estimated for populations and individual pedigrees in many tree species by comparing the mean performance of selfed progeny with related outcrossed progeny. The traditional use of outcrossed progeny as the reference population (F= 0) can introduce bias into the estimation of ID for individual pedigreesas well as forpopulationsdueto unequal contributionsof parentalbreeding valuesto selfed and outcrossed progeny. In addition,maternaleffectsandheterogeneous variancesamong selfed and outcrossedfamiliesmay further distort estimates of population and individual ID.},
	language = {en},
	journal = {Forest Genetics},
	author = {Wu, Harry X and Burdon, Rowland D},
	month = aug,
	year = {2000},
	pages = {267--275},
}

Inbreeding depression (ID) has been estimated for populations and individual pedigrees in many tree species by comparing the mean performance of selfed progeny with related outcrossed progeny. The traditional use of outcrossed progeny as the reference population (F= 0) can introduce bias into the estimation of ID for individual pedigreesas well as forpopulationsdueto unequal contributionsof parentalbreeding valuesto selfed and outcrossed progeny. In addition,maternaleffectsandheterogeneous variancesamong selfed and outcrossedfamiliesmay further distort estimates of population and individual ID.