Renate Scheibe
Universität Osnabrück, Plant Physiology, Faculty Member
Tropical mountain ecosystems are threatened by climate and land-use changes. Their diversity and complexity make projections how they respond to environmental changes challenging. A suitable way are trait-based approaches, by... more
Tropical mountain ecosystems are threatened by climate and land-use changes. Their diversity and complexity make projections how they respond to environmental changes challenging. A suitable way are trait-based approaches, by distinguishing between response traits that determine the resistance of species to environmental changes and effect traits that are relevant for species' interactions, biotic processes, and ecosystem functions. The combination of those approaches with land surface models (LSM) linking the functional community composition to ecosystem functions provides new ways to project the response of ecosystems to environmental changes. With the interdisciplinary project RESPECT, we propose a research framework that uses a trait-based response-effect-framework (REF) to quantify relationships between abiotic conditions, the diversity of functional traits in communities, and associated biotic processes, informing a biodiversity-LSM. We apply the framework to a megadiverse...
Research Interests: Biology, Ecology, Biodiversity, Medicine, Trait, and 3 moreOecologia, Ecosystem, and Threatened Species
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... Key words: climatic irregularities, cloudiness, flowering, fruiting, phenology, tropical mountain forest. e-mail: [email protected] Page 2. ... Biotropica 15: 8189. Borchert, R., Renner, SS, Calle, Z., Navarrete, D., Tye,... more
... Key words: climatic irregularities, cloudiness, flowering, fruiting, phenology, tropical mountain forest. e-mail: [email protected] Page 2. ... Biotropica 15: 8189. Borchert, R., Renner, SS, Calle, Z., Navarrete, D., Tye, A., Gautier, L., Spichiger, R., & P. von Hildebraand. ...
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This study addresses transpiration in a tropical evergreen mountain forest in the Ecuadorian Andes from the leaf to the stand level, with emphasis on nocturnal plant-water relations. The stand level: Evapotranspiration (ET) measured over... more
This study addresses transpiration in a tropical evergreen mountain forest in the Ecuadorian Andes from the leaf to the stand level, with emphasis on nocturnal plant-water relations. The stand level: Evapotranspiration (ET) measured over 12 months with the Eddy-Covariance (ECov) technique proved as the major share (79%) of water received from precipitation. Irrespective of the humid climate, the vegetation transpired day and night. On average, 15.3% of the total daily ET were due to nocturnal transpiration. Short spells of drought increased daily ET, mainly by enhanced nighttime transpiration. Following leaf transpiration rather than air temperature and atmospheric water vapor deficit, ET showed its maximum already in the morning hours. The tree level: Due to the humid climate, the total water consumption of trees was generally low. Nevertheless, xylem sap flux measurements separated the investigated tree species into a group showing relatively high and another one with low sap flux...
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Here we report the first complete sequence of plant cytosolic malate dehydrogenase (EC 1.1.1.37). The phylogenetic relationships between malate dehydrogenases from different cell compartments are discussed. The constructed phylogenetic... more
Here we report the first complete sequence of plant cytosolic malate dehydrogenase (EC 1.1.1.37). The phylogenetic relationships between malate dehydrogenases from different cell compartments are discussed. The constructed phylogenetic tree shows that cytosolic NAD-MDH and chloroplast NADP-MDH have evolved through gene duplication of the pre-existing nuclear gene.
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Research Interests: Biochemistry, Chemistry, Catalysis, Kinetics, Medicinal Plants, and 15 moreMedicine, Gel Permeation Chromatography, Enzyme, High Pressure Liquid Chromatography, Amino Acids, Thioredoxin, Dehydrogenase, Fabaceae, Molecular weight, Carboxypeptidases, Guanidines, Protein Denaturation, Biochemistry and cell biology, Chloroplasts, and proteolysis
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The properties of the system which reverses light modulation of NADP-dependent malate dehydrogenase and glucose-6-phosphate dehydrogenase activity in pea chloroplasts were examined. A factor catalyzing dark modulation of these enzymes was... more
The properties of the system which reverses light modulation of NADP-dependent malate dehydrogenase and glucose-6-phosphate dehydrogenase activity in pea chloroplasts were examined. A factor catalyzing dark modulation of these enzymes was found. This factor cochromatographed with thioredoxin in all systems used (Sephacryl S-200, Sephadex G-75, DEAE-cellulose). Inhibition of dithiothreitol-dependent modulation and of dark reversal by antibody against Escherichia coli thioredoxin further suggest that the dark factor is in fact thioredoxin. It appears that the reaction is the reverse of the previously described dithiothreitol-dependent thioredoxin-catalyzed modulation of enzymes. The limiting step in vitro seems to be the oxidation of thioredoxin during the dark period.
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Biodiversity and ecosystem functions are highly threatened by global change. It has been proposed that geodiversity can be used as an easy-to-measure surrogate of biodiversity to guide conservation management. However, so far, there is... more
Biodiversity and ecosystem functions are highly threatened by global change. It has been proposed that geodiversity can be used as an easy-to-measure surrogate of biodiversity to guide conservation management. However, so far, there is mixed evidence to what extent geodiversity can predict biodiversity and ecosystem functions at the regional scale relevant for conservation planning. Here, we analyse how geodiversity computed as a compound index is suited to predict the diversity of four taxa and associated ecosystem functions in a tropical mountain hotspot of biodiversity and compare the results with the predictive power of environmental conditions and resources (climate, habitat, soil). We show that combinations of these environmental variables better explain species diversity and ecosystem functions than a geodiversity index and identified climate variables as more important predictors than habitat and soil variables, although the best predictors differ between taxa and functions....
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Plant-assisted bioremediation (rhizoremediation) stands out as a potential tool to inactivate or completely remove xenobiotics from the polluted environment. Therefore, it is of key importance to find an adequate combination of plant... more
Plant-assisted bioremediation (rhizoremediation) stands out as a potential tool to inactivate or completely remove xenobiotics from the polluted environment. Therefore, it is of key importance to find an adequate combination of plant species and microorganisms that together enhance the clean-up process. To understand the response of plants upon bioaugmentation, the antioxidative and detoxification system was analyzed in high and low erucic acid rapeseed varieties (HEAR and LEAR, respectively), after 8 weeks of their treatment with petroleum degraders and 6000 mg diesel oil/kg dry soil. The oxidative stress was enhanced in LEAR being exposed to sole diesel oil, in comparison with HEAR. However, when LEAR plants were additionally inoculated with bacteria, suppression of total catalase (CAT) and ascorbate peroxidase (APX) activity were observed. Interestingly, glutathione transferase (GST) activity was found in these plants at a much higher level than in HEAR, which correlated with a more efficient diesel removal performed by LEAR in the polluted soil and upon bioaugmentation. A distinct profile of polycyclic aromatic hydrocarbons (PAH) was detected in leaves of these plants. Neither LEAR nor HEAR experienced any changes in the photosynthetic capacity upon diesel pollution and presence of petroleum degraders, which supports the usefulness of rhizoremediation with rapeseed.
Research Interests: Chemistry, Photosynthesis, Bioremediation, Biology, Oxidative Stress, and 15 moreEnvironmental Chemistry, Environmental Pollution, Medicine, Biological Sciences, Antioxidants, Environmental Sciences, Chlorophyll, Bacteria, Bioaugmentation, Lipid peroxidation, CHEMICAL SCIENCES, Diesel Fuel, Biostimulation, Brassica Napus, and Gasoline
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Research Interests: Botany, Horticulture, Plant Biology, Biology, Phenology, and 4 moreFlora, Senecio, Beech, and Growing Season
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Research Interests: Biochemistry, Biophysics, Photosynthesis, Plant Biology, Biology, and 6 moreMedicine, Enzyme, Small Molecule, Chloroplast, Thiol, and Redox
This study addresses transpiration in a tropical evergreen mountain forest in the Ecuadorian Andes from the leaf to the stand level, with emphasis on nocturnal plant-water relations. The stand level: Evapotranspiration (ET) measured over... more
This study addresses transpiration in a tropical evergreen mountain forest in the Ecuadorian Andes from the leaf to the stand level, with emphasis on nocturnal plant-water relations. The stand level: Evapotranspiration (ET) measured over 12 months with the Eddy-Covariance (ECov) technique proved as the major share (79%) of water received from precipitation. Irrespective of the humid climate, the vegetation transpired day and night. On average, 15.3% of the total daily ET were due to nocturnal transpiration. Short spells of drought increased daily ET, mainly by enhanced nighttime transpiration. Following leaf transpiration rather than air temperature and atmospheric water vapor deficit, ET showed its maximum already in the morning hours. The tree level: Due to the humid climate, the total water consumption of trees was generally low. Nevertheless, xylem sap flux measurements separated the investigated tree species into a group showing relatively high and another one with low sap flux rates. The leaf level: Transpiration rates of Tapirira guianensis, a member of the high-flux-rate group, were more than twice those of Ocotea aciphylla, a representative of the group showing low sap flux rates. Representatives of the Tapirira group operated at a relatively high leaf water potential but with a considerable diurnal amplitude, while the leaves of the Ocotea group showed low water potential and small diurnal fluctuations. Overall, the Tapirira group performed anisohydrically and the Ocotea group isohydrically. Grouping of the tree species by their water relations complied with the extents of the diurnal stem circumference fluctuations. Nighttime transpiration and hydrological type: In contrast to the isohydrically performing trees of the Ocotea group, the anisohydric trees showed considerable water vapour pressure deficit (VPD)-dependent nocturnal transpiration. Therefore, we conclude that nighttime ET at the forest level is mainly sourced by the tree species with anisohydric performance.
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We have developed a method for the purification of chloroplasts from green-pepper fruits. These chloroplasts are characterized by a high degree of intactness and low contamination with other cellular components. The purified chloroplasts... more
We have developed a method for the purification of chloroplasts from green-pepper fruits. These chloroplasts are characterized by a high degree of intactness and low contamination with other cellular components. The purified chloroplasts perform CO2 fixation and posses a fructose-1,6-bisphosphate phosphatase, necessary for the conversion of CO2 to starch. Besides carbon dioxide, these chloroplasts take up external carbon skeletons as
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In yeast and animal cells, mitochondrial disturbances resulting from imbalances in the respiratory chain require malate dehydrogenase (MDH) activities for re-directing fluxes of reducing equivalents. In plants, in addition to... more
In yeast and animal cells, mitochondrial disturbances resulting from imbalances in the respiratory chain require malate dehydrogenase (MDH) activities for re-directing fluxes of reducing equivalents. In plants, in addition to mitochondria, plastids use malate valves to counterbalance and maintain redox-homeostasis. Arabidopsis expresses three cytosolic MDH isoforms, namely cyMDH1, cyMDH2, and cyMDH3, the latter possessing an N-terminal extension carrying a unique cysteine residue C2. In this study, redox-effects on activity and structure of all three cyMDH isoforms were analyzed in vitro. cyMDH1 and cyMDH2 were reversibly inactivated by diamide treatment, accompanied by dimerization via disulfide-bridge formation. In contrast, cyMDH3 forms dimers and higher oligomers upon oxidation, but its low specific activity is redox-independent. In the presence of glutathione, cyMDH1 and cyMDH2 are protected from dimerization and inactivation. In contrast, cyMDH3 still dimerizes but does not fo...
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Research Interests: Botany, Horticulture, Plant Biology, Biology, Phenology, and 4 moreFlora, Senecio, Beech, and Growing Season
Research Interests: Biochemistry, Biology, Medicine, Biological Sciences, Organelles, and 15 moreAntibodies, Plant Physiology, Animals, Polymerase Chain Reaction, Gene, Enzyme, Dehydrogenase, Isoenzymes, Solanum Tuberosum, Rabbits, Amino Acid Sequence, Base Sequence, Recombinant Proteins, Immunoblotting, and Molecular Sequence Data
A full-length cDNA encoding light-activated chloroplast NADP-malate dehydrogenase (NADP-MDH) (EC 1.1.1.82) from pea (Pisum sativum L.) was introduced in the sense and antisense orientation into tobacco (Nicotiana tabacum L.). Transgenic... more
A full-length cDNA encoding light-activated chloroplast NADP-malate dehydrogenase (NADP-MDH) (EC 1.1.1.82) from pea (Pisum sativum L.) was introduced in the sense and antisense orientation into tobacco (Nicotiana tabacum L.). Transgenic plants with decreased or increased expression levels were obtained. Because of substantial age-dependent differences in individual leaves of a single plant, standardization of NADP-MDH levels was required first. Then, extent and stability of over- or under-expression of Nmdh, the gene encoding NADP-MDH, was characterized in the various transformants. Frequently, cosuppression effects were observed, indicating sufficient homology between the endogenous tobacco and the heterologous pea gene. Analysis of the T1 and T2 progeny of a series of independent transgenic lines revealed that NADP-MDH capacity ranged between 10% and [greater than or equal to]10-fold compared with the wild type. Under ambient conditions whole-plant development, growth period, and ...
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The dark form of NADP‐malate dehydrogenase from pea leaves which has been shown to contain one disulfide bridge per subunit does not exhibit any catalytic activity in the absence of thiol reducing agents. Upon reduction of these disulfide... more
The dark form of NADP‐malate dehydrogenase from pea leaves which has been shown to contain one disulfide bridge per subunit does not exhibit any catalytic activity in the absence of thiol reducing agents. Upon reduction of these disulfide bridges the enzyme becomes catalytically active. In this presentation, however, it is shown that the oxidized dark form of NADP‐malate dehydrogenase becames catalytically competent when assayed in the presence of 200–250 mM guanidine‐HCl. This guanidine‐dependent activity of the oxidized enzyme is characterized by higher apparent K m values for the substratres as compared to the reduced enzyme, but is still specific for NADPH. Up to 25% of the V maxOf the reduced enzyme was obtained for the oxidized guanidine‐activated NADP‐malate dehydrogenase. The results suggest that the reduction of the regulatory disulfide is not essential for catalytic activity.
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Mitochondrial alternative oxidase (AOX) in plants is a non-proton-motive ubiquinol oxidase that is activated by redox mechanisms and 2-oxo acids. A comparative analysis of AOX isoenzymes AOX1A, AOX1C, and AOX1D from Arabidopsis thaliana... more
Mitochondrial alternative oxidase (AOX) in plants is a non-proton-motive ubiquinol oxidase that is activated by redox mechanisms and 2-oxo acids. A comparative analysis of AOX isoenzymes AOX1A, AOX1C, and AOX1D from Arabidopsis thaliana revealed that cysteine residues, CysI and CysII, are both involved in 2-oxo acid activation, with AOX1A activity being more increased by 2-oxo acids than that of AOX1C and AOX1D. Substitution of cysteine in AOX1A by glutamate mimiked its activation by pyruvate or glyoxylate, but not in AOX1C and AOX1D. CysIII, only present in AOX1A, is not involved in activation by reduction or metabolites, but substitutions at this position affected activity. AOX1A carrying a serine residue at position CysI was activated by succinate, while correspondingly substituted variants of AOX1C and AOX1D were insensitive. Activation by glutamate at CysI and CysII is consistent with the formation of the thiohemiacetal, while succinate activation after changing CysI to serine ...
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<b>Copyright information:</b>Taken from "Regulation of gene expression by photosynthetic signals triggered through modified COavailability"BMC Plant Biology 2006;6():15-15.Published online 17 Aug... more
<b>Copyright information:</b>Taken from "Regulation of gene expression by photosynthetic signals triggered through modified COavailability"BMC Plant Biology 2006;6():15-15.Published online 17 Aug 2006PMCID:PMC1579212. The data are means of n = 4–6, ± SE from at least 4 different experiments.
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<p><b>(A)</b> Flavonoid content was determined from field-grown and greenhouse-grown plants according to Kishore et al. [<a... more
<p><b>(A)</b> Flavonoid content was determined from field-grown and greenhouse-grown plants according to Kishore et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0202255#pone.0202255.ref015" target="_blank">15</a>] with rutin for calibration. <b>(B)</b> Total phenolics were determined according to Singleton and Rossi [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0202255#pone.0202255.ref043" target="_blank">43</a>] with gallic acid for calibration. The graphs show the mean ± SEM of three biological replicates. The letters a, b and c indicate the level of significant differences (p ≤ 0.05) towards each other. Significance was calculated by ANOVA followed by Tukey’s pairwise comparisons.</p
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