Dark CO2 fixation by cell-free preparations of the wood of Robinia pseudoacacia

1974 ◽  
Vol 52 (4) ◽  
pp. 727-734 ◽  
Author(s):  
Wolfgang Höll
Keyword(s):  
Organic Compounds ◽  
Malic Enzyme ◽  
Co2 Fixation ◽  
Robinia Pseudoacacia ◽  
Physiological Role ◽  
Annual Rings ◽  
Ph Optimum ◽  
Robinia Pseudoacacia L ◽  
Dark Co2 Fixation

In the presence of phosphoenolpyruvate, cell-free preparations from distinct annual ring tissues of the trunk and the root of Robinia pseudoacacia L. incorporate 14CO2 into organic compounds. The CO2 fixation process exhibits a pH optimum at 7.8 and is activated by Mg2+. Aspartic acid contained 97% of the radioactivity incorporated. Oligosaccharides, malic acid, fumaric acid, glutamic acid, and three substances not identified with certainty show minor labeling. The activities of malate dehydrogenase (EC. 1.1.1.37), aspartate aminotransferase (EC. 2.6.1.1), and "malic enzyme" (EC. 1.1.1.40), involved in the further metabolism of the primary CO2 fixation product oxaloacetate, were detected spectrophotometrically in preparations from different annual rings of the trunk. Compared with the outer zones, the innermost part of the sapwood shows only little activity of these enzymes. The capacity to transfer CO2 into organic compounds decreases in the radial direction of both trunk and root wood. Heartwood preparations exhibit no CO2 fixation. In comparison to the trunk, the wood of the root shows only little dark CO2 fixation. The possible physiological role of this nonautotrophic CO2 binding in the wood of Robinia is discussed.

Productivity and Environmental Role of Forest Shelterbelts of Robinia pseudoacacia L. of the Kuban Lowland

2020 ◽  
pp. 88-97
Author(s):  
V.V. Tanyukevich ◽  
◽  
S.V. Tyurin ◽  
D.V. Khmeleva ◽  
A.A. Kvasha ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Land Reclamation ◽  
Poa Pratensis ◽  
Robinia Pseudoacacia ◽  
Average Height ◽  
Middle Aged ◽  
Aboveground Phytomass ◽  
Robinia Pseudoacacia L ◽  
Young Growth

Works on protective afforestation are carried out in order to protect agricultural land from degradation processes, as well as to improve the microclimate of land. The research purpose is to study the bioproductivity and environmental role of Robinia pseudoacacia L. forest shelterbelts in the conditions of the Kuban lowland. The approved and generally accepted methods of forest valuation, forest land reclamation, botany, and mathematical statistics were applied. Plantings were created according to the standard technology for the steppe zone of the Russian Federation. The area of forest shelterbelts is 62.4 ths ha, including 5 % of the young growth (I state class), 80 % of middle-aged forest plantings (II state class), 10 % of maturing plantings (II state class), 5 % of mature and overmature plantings (III state class). Living ground cover is formed by the following species: Koeleria pyramidata L., Poa pratensis L., Festuca pratensis H., Elytrígia repens L., Dactylis glomerata L., and Phlum pratense L. Aboveground phytomass is 100–300 g/m2; height is 25–32 cm. Plantings are characterized by the quality classes: young growth – I and II; middle-aged and maturing – III; mature and overmature – IV. At the age of natural maturity (70 years), the Robinia trunk reaches the average height of 15.1 m with the average diameter of 22.1 cm. The total stock of wood reaches 18, (ths m3), including (ths m3): young growth – 68 (ths m3); middleaged plantings – 14,871 (ths m3); maturing plantings – 2,187 (ths m3); mature and overmature plantings – 1,314 (ths m3). Aboveground phytomass in young growth is 20.2 t/ha; in mature and overmature plantings it is 391.2 t/ha. In the region it is estimated at 17,070 ths t, including (ths t): young growth – 64; middle-aged plantings – 13,753; maturing plantings – 2,032; mature and overmature plantings – 1,221. The share of stem mass reaches 84.5–80.8 %; woody greenery – 4.2–1.5 %; branches – 11.3–17.7 %. Recalculation coefficients of the stock into aboveground phytomass are the following for: young growth – 0.936; mature and overmature forest shelterbelts – 0.929. Phytosaturation of forest shelterbelts varies within 0.314–2.474 kg/m3. Forest shelterbelts have accumulated 8,534 ths t of carbon, which is estimated at 145.1 mln dollars. The sphere of application of the research results is the Krasnodar Krai forestry, which is recommended to create an additional 60 ths ha of forest shelterbelts, which will provide a normative protective forest cover of arable land of 5 % and annual carbon sequestration up to 3.4 t/ha.

scholarly journals YtsJ Has the Major Physiological Role of the Four Paralogous Malic Enzyme Isoforms in Bacillus subtilis

2006 ◽  
Vol 188 (13) ◽  
pp. 4727-4736 ◽  
Author(s):  
Guillaume Lerondel ◽  
Thierry Doan ◽  
Nicola Zamboni ◽  
Uwe Sauer ◽  
Stéphane Aymerich
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Malic Enzyme ◽  
Metabolic Flux ◽  
Physiological Role ◽  
Extreme Case ◽  
Growth Defect ◽  
Flux Analysis ◽  
Malic Enzyme Activity

ABSTRACT The Bacillus subtilis genome contains several sets of paralogs. An extreme case is the four putative malic enzyme genes maeA, malS, ytsJ, and mleA. maeA was demonstrated to encode malic enzyme activity, to be inducible by malate, but also to be dispensable for growth on malate. We report systematic experiments to test whether these four genes ensure backup or cover different functions. Analysis of single- and multiple-mutant strains demonstrated that ytsJ has a major physiological role in malate utilization for which none of the other three genes could compensate. In contrast, maeA, malS, and mleA had distinct roles in malate utilization for which they could compensate one another. The four proteins exhibited malic enzyme activity; MalS, MleA, and MaeA exhibited 4- to 90-fold higher activities with NAD+ than with NADP+. YtsJ activity, in contrast, was 70-fold higher with NADP+ than with NAD+, with Km values of 0.055 and 2.8 mM, respectively. lacZ fusions revealed strong transcription of ytsJ, twofold higher in malate than in glucose medium, but weak transcription of malS and mleA. In contrast, mleA was strongly transcribed in complex medium. Metabolic flux analysis confirmed the major role of YtsJ in malate-to-pyruvate interconversion. While overexpression of the NADP-dependent Escherichia coli malic enzyme MaeB did not suppress the growth defect of a ytsJ mutant on malate, overexpression of the transhydrogenase UdhA from E. coli partially suppressed it. These results suggest an additional physiological role of YtsJ beyond that of malate-to-pyruvate conversion.

scholarly journals The Hydrological-Hydrochemical Factors that Control the Invasion of the Black Locust (Robinia pseudoacacia L.) in Succession in Areas with Opencast Mines

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 40
Author(s):  
Joanna Kidawa ◽  
Damian Chmura ◽  
Tadeusz Molenda
Keyword(s):  
Vascular Plants ◽  
Invasive Alien Species ◽  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Developmental Phase ◽  
Natural Revegetation ◽  
Opencast Mines ◽  
Robinia Pseudoacacia L ◽  
Sandy Sediments

Studies on opencast mines have indicated that the spontaneous colonization of excavations and sedimentation tanks by vegetation is determined not only by the substratum and the land relief, but also by the hydrological and hydrochemical relations in the exploitation hollow. Sometimes, biological invasions can also disturb the natural revegetation. Robinia pseudoacacia L. black locust is an invasive alien species that frequently colonizes sandy habitats. Thirty study plots were randomly established on four types of sites: (1) sandy sediments, extremely dry places located mainly on heaps of post-washer slime; (2) sandy sediments, dry areas that are periodically flooded and have pulp; (3) clay sediments, damp areas that are periodically submerged, and (4) the control, a forest with R. pseudoacacia in its neighborhood. A total of 94 species of vascular plants and seven species of mosses were found. The vegetation at the sites differs and the role of the black locust increases along the dryness gradient and developmental phase of vegetation. Older phases of succession resemble a forest in the surrounding area. It is a R. pseudoacacia species-poor monodominant stand that has been forming for around 30 years. A lack of trees and dense grasses favor the successful invasion of the black locust on man-made sandy habitats.

scholarly journals The substrate specificity of acid α-glucosidase from rabbit muscle

1971 ◽  
Vol 124 (4) ◽  
pp. 701-711 ◽  
Author(s):  
T. N. Palmer
Keyword(s):  
Substrate Inhibition ◽  
Physiological Role ◽  
Liver Glycogen ◽  
Rabbit Muscle ◽  
Ph Optimum ◽  
Enzyme Action ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Hydrolysis Of

1. Acid α-glucosidase was purified 3500-fold from rabbit muscle. 2. The enzyme was activated by cations, the degree of activation varying with the substrate. Enzyme action on glycogen was most strongly activated and activation was apparently of a non-competitive type. With rabbit liver glycogen as substrate, the relative Vmax. increased 15-fold, accompanied by an increase in Km from 8.3 to 68.6mm-chain end over the cation range 2–200mm-Na+ at pH4.5. Action on maltose was only moderately activated (1.3-fold, non-competitively) and action on maltotriose was marginally and competitively inhibited. 3. The pH optimum at 2mm-Na+ was 4.5 (maltose) and 5.1 (glycogen). Cation activation of enzyme action on glycogen was markedly pH-dependent. At 200mm-Na+, the pH optimum was 4.8 and activity was maximally stimulated in the range pH4.5–3.3. 4. Glucosidase action on maltosaccharides was associated with pronounced substrate inhibition at concentrations exceeding 5mm. Of the maltosaccharides tested, the enzyme showed a preference for p-nitrophenyl α-maltoside (Km 1.2mm) and maltotriose (Km 1.8mm). The extrapolated Km for enzyme action on maltose was 3.7mm. 5. The macromolecular polysaccharide substrate glycogen differed from linear maltosaccharide substrates in the kinetics of its interaction with the enzyme. Activity was markedly dependent on pH, cation concentration and polysaccharide structure. There was no substrate inhibition. 6. The enzyme exhibited constitutive α-1,6-glucanohydrolase activity. The Km for panose was 20mm. 7. The enzyme catalysed the total conversion of glycogen into glucose. The hydrolysis of α-1,6-linkages was apparently rate-limiting during the hydrolysis of glycogen. 8. Enzyme action on glycogen and maltose released the α-anomer of d-glucose. 9. The results are discussed in terms of the physiological role of acid α-glucosidase in lysosomal glycogen catabolism.

scholarly journals The Pyruvate Carboxylase of Verticillium albo-atrum

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 15-19 ◽  
Author(s):  
R. E. Hartman ◽  
N. T. Keen
Keyword(s):  
Pyruvate Carboxylase ◽  
Krebs Cycle ◽  
Physiological Role ◽  
Maximum Activity ◽  
Ph Optimum ◽  
Carboxylase Activity ◽  
Metabolic Intermediates ◽  
Krebs Cycle Intermediates ◽  
Verticillium Albo Atrum

The pyruvate carboxylase of Verticillium albo-atrum had a pH optimum of 7·8 and a specific requirement for ATP. At the optimum pH, magnesium ions were required for maximum activity, while at pH 6·8 manganese was more effective than magnesium. Potassium was stimulatory while sodium was ineffective. Avidin and p-chloromercuribenzoate strongly inhibited the enzyme while biotin and dithiothreitol, respectively, reversed the effect of the inhibitors. Aspartate and oxalacetate were inhibitory while acetyl-CoA and CoA reversed the inhibition by aspartate. These cofactors were ineffective in the absence of aspartate. None of the tested metabolic intermediates was stimulatory to pyruvate carboxylase activity while NADP+ and 2,3-diphosphoglycerate were the most effective inhibitors (75%) at a concentration of 6·7 mM. Levels of pyruvate carboxylase in cells grown on glucose, acetate, malate, xylose, glycerol or aspartate differed only slightly. The data indicated that the physiological role of pyruvate carboxylase in V. albo-atrum is the anaplerotic biosynthesis of C4 Krebs-cycle intermediates from pyruvate.

scholarly journals Production and Characterization of a Thermostable Alcohol Dehydrogenase That Belongs to the Aldo-Keto Reductase Superfamily

2006 ◽  
Vol 72 (1) ◽  
pp. 233-238 ◽  
Author(s):  
Ronnie Machielsen ◽  
Agustinus R. Uria ◽  
Servé W. M. Kengen ◽  
John van der Oost
Keyword(s):  
Alcohol Dehydrogenase ◽  
Pyrococcus Furiosus ◽  
Enantiomeric Excess ◽  
Physiological Role ◽  
Secondary Alcohols ◽  
Gene Encoding ◽  
Ph Optimum ◽  
Reduction Of Ketones

ABSTRACT The gene encoding a novel alcohol dehydrogenase that belongs to the aldo-keto reductase superfamily has been identified in the hyperthermophilic archaeon Pyrococcus furiosus. The gene, referred to as adhD, was functionally expressed in Escherichia coli and subsequently purified to homogeneity. The enzyme has a monomeric conformation with a molecular mass of 32 kDa. The catalytic activity of the enzyme increases up to 100°C, and a half-life value of 130 min at this temperature indicates its high thermostability. AdhD exhibits a broad substrate specificity with, in general, a preference for the reduction of ketones (pH optimum, 6.1) and the oxidation of secondary alcohols (pH optimum, 8.8). Maximal specific activities were detected with 2,3-butanediol (108.3 U/mg) and diacetyl-acetoin (22.5 U/mg) in the oxidative and reductive reactions, respectively. Gas chromatrography analysis indicated that AdhD produced mainly (S)-2-pentanol (enantiomeric excess, 89%) when 2-pentanone was used as substrate. The physiological role of AdhD is discussed.

scholarly journals Cloning of the Malic Enzyme Gene fromCorynebacterium glutamicum and Role of the Enzyme in Lactate Metabolism

2000 ◽  
Vol 66 (7) ◽  
pp. 2981-2987 ◽  
Author(s):  
Pierre Gourdon ◽  
Marie-France Baucher ◽  
Nic D. Lindley ◽  
Armel Guyonvarch
Keyword(s):  
Exponential Growth ◽  
Malic Enzyme ◽  
Tricarboxylic Acid Cycle ◽  
Physiological Role ◽  
Growth Period ◽  
Biochemical Properties ◽  
Lactate Metabolism ◽  
Wild Type ◽  
Malic Enzyme Gene

ABSTRACT Malic enzyme is one of at least five enzymes, known to be present in Corynebacterium glutamicum, capable of carboxylation and decarboxylation reactions coupling glycolysis and the tricarboxylic acid cycle. To date, no information is available concerning the physiological role of the malic enzyme in this bacterium. ThemalE gene from C. glutamicum has been cloned and sequenced. The protein encoded by this gene has been purified to homogeneity, and the biochemical properties have been established. Biochemical characteristics indicate a decarboxylation role linked to NADPH generation. Strains of C. glutamicum in which themalE gene had been disrupted or overexpressed showed no detectable phenotype during growth on either acetate or glucose, but showed a significant modification of growth behavior during lactate metabolism. The wild type showed a characteristic brief period of exponential growth on lactate followed by a linear growth period. This growth pattern was further accentuated in a malE-disrupted strain (ΔmalE). However, the strain overexpressingmalE maintained exponential growth until all lactate had been consumed. This strain accumulated significantly larger amounts of pyruvate in the medium than the other strains.

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