Thermal Adaptation and Acclimation of Higher Plants at the Enzyme Level: Thermostability of Nad Malate Dehydrogenase in Three Species of Viola

1985 ◽  
Vol 73 (2) ◽  
pp. 397 ◽  
Author(s):  
J.-P. Simon ◽  
C. Charest ◽  
M.-J. Peloquin
Keyword(s):  
Malate Dehydrogenase ◽  
Higher Plants ◽  
Enzyme Level ◽  
Thermal Adaptation

Adaptation and acclimation of higher plants at the enzyme level: thermal properties of NAD malate dehydrogenase of two species of Aster (Asteraceae) and their hybrid adapted to contrasting habitats

1980 ◽  
Vol 58 (13) ◽  
pp. 1474-1481 ◽  
Author(s):  
Luc Brouillet ◽  
Jean-Pierre Simon
Keyword(s):  
Malate Dehydrogenase ◽  
Higher Plants ◽  
Enzyme Level ◽  
Leaf Tissue ◽  
Forest Understory ◽  
Kinetic Properties ◽  
Peptidase Activity ◽  
Crude Extracts ◽  
Contrasting Habitats ◽  
Sphagnum Bog

Thermal and kinetic properties of NAD malate dehydrogenase (MDH) were investigated in clonal populations of two species of Aster and their hybrid: A. acuminatus, a forest understory species; A. nemoralis, a sphagnum-bog species; and A. blakei, their hybrid occurring at the bog–forest ecotone. The populations were collected within a 300 m radius in southwestern Quebec. Compared with A. acuminatus, the MDH of crude extracts from A. nemoralis had lower thermostability in both 5- and 10-min assays at 55 °C, and reduced apparent energy of activation (Ea) in the temperature range of 15–25 °C. However, these differences were not maintained in purified extracts of the species and may be attributed to higher phenolase and peptidase activity in crude extracts of A. nemoralis. The ratio of MDH activity over total protein concentration, or fresh weight leaf tissue, was higher in A. acuminatus than in A. nemoralis. Most values for these MDH properties of A. blakei were intermediate between those of the two parents. No differences, however, were observed for the substrate binding ability (Km) of MDH in the three taxa. Electrophoretic analyses show no qualitative differentiation in the enzyme profiles of MDH of the three taxa, which consist of two mitochondrial and six cytosolic isozymes. Mitochondrial isozymes were more thermostable but no differences in thermostability were observed among the forms of the species. The thermal and kinetic properties of malate dehydrogenase, as measured in situ, have not been substantially modified by the contrasting microclimatic regimes associated with the habitats of A. acuminatus and A. nemoralis.

Thermal adaptation and acclimation of ecotypic populations of Spirodela polyrhiza (Lemnaceae): thermostability and apparent activation energy of NAD malate dehydrogenase

1981 ◽  
Vol 59 (6) ◽  
pp. 1061-1068 ◽  
Author(s):  
Dominique Davidson ◽  
Jean-Pierre Simon
Keyword(s):  
Activation Energy ◽  
Malate Dehydrogenase ◽  
Aquatic Plant ◽  
Thermal Adaptation ◽  
Terrestrial Plants ◽  
Spirodela Polyrhiza ◽  
Average Temperature ◽  
Origin Activation ◽  
Regulatory Systems ◽  
Bodies Of Water

Eleven ecotypes of Spirodela polyrhiza (L.) Schleid., an aquatic plant possessing an extensive geographic distribution, were studied to detect adaptive and acclimatory metabolic changes through a study of the thermostability and activation energy of malate dehydrogenase. Colonies were grown under controlled conditions with temperature (18, 23, and 28 °C) as the only variable. Thermostability is found to be affected by experimental temperatures (acclimation) but not by origin temperatures; there is genetic differentiation but related to some other environmental conditions than average temperature at the site of origin. Activation energy is unaffected by experimental temperatures or origin. It is suggested that, as S. polyrhiza naturally grows in bodies of water, it is less exposed to temperature variations than terrestrial plants, but is more affected by other physicochemical environmental factors; its main metabolic regulatory systems do not appear to be associated with thermal controls.

scholarly journals Aconitase: To Be or not to Be Inside Plant Glyoxysomes, That Is the Question

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 162
Author(s):  
Luigi De Bellis ◽  
Andrea Luvisi ◽  
Amedeo Alpi
Keyword(s):  
Malate Dehydrogenase ◽  
Metabolic Pathways ◽  
Higher Plants ◽  
Glyoxylate Cycle ◽  
Genetic Research ◽  
Transcriptomic Analysis ◽  
Plant Biology ◽  
New Model ◽  
The Glyoxylate Cycle

After the discovery in 1967 of plant glyoxysomes, aconitase, one the five enzymes involved in the glyoxylate cycle, was thought to be present in the organelles, and although this was found not to be the case around 25 years ago, it is still suggested in some textbooks and recent scientific articles. Genetic research (including the study of mutants and transcriptomic analysis) is becoming increasingly important in plant biology, so metabolic pathways must be presented correctly to avoid misinterpretation and the dissemination of bad science. The focus of our study is therefore aconitase, from its first localization inside the glyoxysomes to its relocation. We also examine data concerning the role of the enzyme malate dehydrogenase in the glyoxylate cycle and data of the expression of aconitase genes in Arabidopsis and other selected higher plants. We then propose a new model concerning the interaction between glyoxysomes, mitochondria and cytosol in cotyledons or endosperm during the germination of oil-rich seeds.

scholarly journals Thioredoxin-h1 Reduces and Reactivates the Oxidized Cytosolic Malate Dehydrogenase Dimer in Higher Plants

2006 ◽  
Vol 281 (43) ◽  
pp. 32065-32071 ◽  
Author(s):  
Satoshi Hara ◽  
Ken Motohashi ◽  
Fumio Arisaka ◽  
Patrick G. N. Romano ◽  
Naomi Hosoya-Matsuda ◽  
...  
Keyword(s):  
Affinity Chromatography ◽  
Malate Dehydrogenase ◽  
Higher Plants ◽  
Peptide Mapping ◽  
Target Protein ◽  
Reduced Form ◽  
Mutant Analysis ◽  
Low Concentrations ◽  
Mapping Analysis ◽  
Cytosolic Malate Dehydrogenase

Cytosolic malate dehydrogenase (cytMDH) was captured by thioredoxin affinity chromatography as a possible target protein of cytosolic thioredoxin (Yamazaki, D., Motohashi, K., Kasama, T., Hara, Y., and Hisabori, T. (2004) Plant Cell Physiol. 45, 18–27). To further dissect this interaction, we aimed to determine whether cytMDH can interact with the cytosolic thioredoxin and whether its activity is redox-regulated. We obtained the active recombinant cytMDH that could be oxidized and rendered inactive. Inactivation was reversed by incubation with low concentrations of dithiothreitol in the presence of recombinant Arabidopsis thaliana thioredoxin-h1. Inactivation of cytMDH was found to result from formation of a homodimer. By cysteine mutant analysis and peptide mapping analysis, we were able to determine that the cytMDH homodimer occurs by formation of a disulfide bond via the Cys330 residue. Moreover, we found this bond to be efficiently reduced by the reduced form of thioredoxin-h1. These results demonstrate that the oxidized form cytMDH dimer is a preferable target protein of the reduced form thioredoxin-h1 as suggested by thioredoxin affinity chromatography.

scholarly journals Thermal adaptation in the honeybee (Apis mellifera) via changes to the structure of malate dehydrogenase

2020 ◽  
Vol 223 (18) ◽  
pp. jeb228239
Author(s):  
Thitipan Meemongkolkiat ◽  
Jane Allison ◽  
Frank Seebacher ◽  
Julianne Lim ◽  
Chanpen Chanchao ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Malate Dehydrogenase ◽  
High Temperatures ◽  
Thermal Adaptation ◽  
Allele Frequencies ◽  
Clinal Variation ◽  
Dehydrogenase Gene ◽  
S Allele ◽  
Dynamics Simulations

ABSTRACTIn honeybees there are three alleles of cytosolic malate dehydrogenase gene: F, M and S. Allele frequencies are correlated with environmental temperature, suggesting that the alleles have temperature-dependent fitness benefits. We determined the enzyme activity of each allele across a range of temperatures in vitro. The F and S alleles have higher activity and are less sensitive to high temperatures than the M allele, which loses activity after incubation at temperatures found in the thorax of foraging bees in hot climates. Next, we predicted the protein structure of each allele and used molecular dynamics simulations to investigate their molecular flexibility. The M allozyme is more flexible than the S and F allozymes at 50°C, suggesting a plausible explanation for its loss of activity at high temperatures, and has the greatest structural flexibility at 15°C, suggesting that it can retain some enzyme activity at cooler temperatures. MM bees recovered from 2 h of cold narcosis significantly better than all other genotypes. Combined, these results explain clinal variation in malate dehydrogenase allele frequencies in the honeybee at the molecular level.

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