Glycerol metabolism in Rhizobium

1976 ◽  
Vol 22 (2) ◽  
pp. 150-153 ◽  
Author(s):  
A. Arias ◽  
G. Martinez-Drets
Keyword(s):  
Metabolic Pathway ◽  
Glycerol Kinase ◽  
Rhizobium Japonicum ◽  
Glycerol Dehydrogenase ◽  
Glycerol Metabolism ◽  
Glycerophosphate Dehydrogenase ◽  
Slow Growing

Four strains of Rhizobium japonicum and one strain of R. trifolii were grown on glycerol and found to contain a soluble ATP-glycerol kinase and a particulate glycerophosphate dehydrogenase. Both enzymes are induced by glycerol. The presence of NAD+– or NADP+–glycerol dehydrogenase was not detected in any of the strains. No significant differences were found in the glycerol metabolic pathway between fast- and slow-growing rhizobia.

Glycerol metabolism in rabbits

1968 ◽  
Vol 46 (9) ◽  
pp. 1107-1114 ◽  
Author(s):  
Jean Himms-Hagen
Keyword(s):  
Turnover Rate ◽  
Glycerol Kinase ◽  
Rabbit Liver ◽  
Constant Infusion ◽  
Glycerol Dehydrogenase ◽  
Glycerol Metabolism ◽  
Utilization Rate ◽  
Glycerol Concentration ◽  
Glycerol Utilization ◽  
Fractional Turnover

The endogenous rate of glycerol production in rabbits was measured by several techniques: constant infusion of 1,3-14C-glycerol or 2-3H-glycerol or unlabeled glycerol; single injection of 1,3-14C-glycerol or 2-3H-glycerol or unlabeled glycerol. The rate was 5.5–11.6 μmoles/kg per minute (9 rabbits). The mean fractional turnover rate was 0.0585 ± 0.0052. During infusion of noradrenaline together with 3H-glycerol, the fractional turnover rate was no different from that in the absence of noradrenaline. The maximum utilization rate of glycerol was 28.1 ± 1.40 μmoles/kg per minute. The glycerol space was 58.1% of body weight. The relationship of glycerol concentration to rate of glycerol utilization in the intact rabbit suggests the existence of an enzyme with a KM for glycerol of 0.33 × 10−3 M; the glycerol kinase of rabbit liver was found to have a KM for glycerol of 0.29 × 10−3 M. This enzyme could account for the disappearance of glycerol in the intact animal except that its Vmax is only 4% of that expected. Possible reasons for this are discussed. A glycerol dehydrogenase with a Vmax similar to that of the glycerol kinase also exists in rabbit liver; its KM for glycerol is so high (0.5 M) that it is unlikely to play a significant role in glycerol metabolism in the normal rabbit.

Etude de deux mutants du métabolisme du glycérol chez Bacillus subtilis

1972 ◽  
Vol 18 (8) ◽  
pp. 1315-1325 ◽  
Author(s):  
S. A. Saheb
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Wild Strain ◽  
Glycerol Kinase ◽  
Glycerol Dehydrogenase ◽  
Dihydroxyacetone Phosphate ◽  
Microbial Species ◽  
Glycerophosphate Dehydrogenase ◽  
Dihydroxyacetone Kinase

As in different microbial species, two pathways for the degradation of glycerol are found in B. subtilis 168. Each pathway includes two enzymes which can catalyze the formation of dihydroxyacetone phosphate from glycerol in vitro. The first pathway includes a glycerol dehydrogenase (gl-D) and a dihydroxyacetone kinase (dha-K). The second pathway includes a glycerol kinase (gl-K) and an α-glycerophosphate dehydrogenase (glp-D). Enzymes of both pathways are repressed in the presence of glucose. Only the enzymes of the second pathway are inducible. The inducer is probably glycerophosphate, utilization of which as a carbon source by B. subtilis is demonstrated. Degradation of glycerol in B. subtilis proceeds through the second pathway. This was demonstrated by the isolation of a mutant (gl−2) impaired in glycerol kinase, and which cannot use glycerol as a carbon source. Another mutant (gl−1)was isolated, which cannot use glycerol as a carbon source. When comparing the activity of the four enzymes, particularly gl-K, no significant differences were observed between the wild strain and the mutant gl−1. This leads one to consider the existence of a glycerol permeation system in B. subtilis. A mutation affecting this system would explain the behavior of the mutant gl−1.

scholarly journals Renal glycerol metabolism and the distribution of glycerol kinase in rabbit nephron

1981 ◽  
Vol 198 (3) ◽  
pp. 543-549 ◽  
Author(s):  
G Wirthensohn ◽  
A Vandewalle ◽  
W G Guder
Keyword(s):  
Glycerol Kinase ◽  
The Other ◽  
Rabbit Kidney ◽  
Glycerol Metabolism ◽  
Kidney Cortex ◽  
Collagenase Treatment ◽  
Uptake Rates ◽  
Metabolic Products ◽  
Pars Recta ◽  
Convoluted Tubules

Glycerol and dihydroxyacetone are metabolized by rabbit kidney-cortex tubules, isolated by collagenase treatment. Half-maximal concentrations of both substrates were determined with regard to uptake rates and product formations. Maximal uptake rates were 643 and 329 mumol/h per g of protein for dihydroxyacetone and glycerol respectively. Glucose and lactate were found as major metabolic products. Glycerol kinase, the enzyme catalysing the first step in renal glycerol and dihydroxyacetone metabolism, was measured radiochemically as described by Newsholme, Robinson & Taylor [(1967) Biochim, Biophys. Acta 132, 338-346] and adapted for studies of the localization of this enzyme along the different structures of rabbit nephron. The results show that glycerol kinase is located exclusively in the proximal segments, i.e. the proximal convoluted tubules and the pars recta, but is negligible in the other structures studied. The activities were close to the maximal dihydroxyacetone uptake rates measured in tubule suspensions.

scholarly journals Fermentation of Glycerol to Succinate by Metabolically Engineered Strains of Escherichia coli

2010 ◽  
Vol 76 (8) ◽  
pp. 2397-2401 ◽  
Author(s):  
Xueli Zhang ◽  
K. T. Shanmugam ◽  
Lonnie O. Ingram
Keyword(s):  
Escherichia Coli ◽  
Electron Acceptors ◽  
Carbon Flow ◽  
Glycerol Dehydrogenase ◽  
Glycerol Metabolism ◽  
Wild Type ◽  
Anaerobic Conditions ◽  
Mineral Salts ◽  
Succinate Production ◽  
Fermentation Products

ABSTRACT The fermentative metabolism of Escherichia coli was reengineered to efficiently convert glycerol to succinate under anaerobic conditions without the use of foreign genes. Formate and ethanol were the dominant fermentation products from glycerol in wild-type Escherichia coli ATCC 8739, followed by succinate and acetate. Inactivation of pyruvate formate-lyase (pflB) in the wild-type strain eliminated the production of formate and ethanol and reduced the production of acetate. However, this deletion slowed growth and decreased cell yields due to either insufficient energy production or insufficient levels of electron acceptors. Reversing the direction of the gluconeogenic phosphoenolpyruvate carboxykinase reaction offered an approach to solve both problems, conserving energy as an additional ATP and increasing the pool of electron acceptors (fumarate and malate). Recruiting this enzyme through a promoter mutation (pck*) to increase expression also increased the rate of growth, cell yield, and succinate production. Presumably, the high NADH/NAD+ ratio served to establish the direction of carbon flow. Additional mutations were also beneficial. Glycerol dehydrogenase and the phosphotransferase-dependent dihydroxyacetone kinase are regarded as the primary route for glycerol metabolism under anaerobic conditions. However, this is not true for succinate production by engineered strains. Deletion of the ptsI gene or any other gene essential for the phosphotranferase system was found to increase succinate yield. Deletion of pflB in this background provided a further increase in the succinate yield. Together, these three core mutations (pck*, ptsI, and pflB) effectively redirected carbon flow from glycerol to succinate at 80% of the maximum theoretical yield during anaerobic fermentation in mineral salts medium.

scholarly journals Insights into an alternative pathway for glycerol metabolism in a glycerol kinase deficientPseudomonas putidaKT2440

2019 ◽  
Author(s):  
Meg Walsh ◽  
William Casey ◽  
Shane T. Kenny ◽  
Tanja Narancic ◽  
Lars M. Blank ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Alternative Pathway ◽  
Glycerol Kinase ◽  
Glycerol Metabolism ◽  
Wild Type ◽  
Short Chain Length ◽  
Genes Encoding ◽  
In The Wild

AbstractPseudomonas putidaKT2440 is known to metabolise glycerol via glycerol-3-phosphate using glycerol kinase an enzyme previously described as critical for glycerol metabolism (1). However, when glycerol kinase was knocked out inP. putidaKT2440 it retained the ability to use glycerol as the sole carbon source, albeit with a much-extended lag period and 2 fold lower final biomass compared to the wild type strain. A metabolomic study identified glycerate as a major and the most abundant intermediate in glycerol metabolism in this mutated strain with levels 21-fold higher than wild type. Erythrose-4-phosphate was detected in the mutant strain, but not in the wild type strain. Glyceraldehyde and glycraldehyde-3-phosphate were detected at similar levels in the mutant strain and the wild type. Transcriptomic studies identified 191 genes that were more than 2-fold upregulated in the mutant compared to the wild type and 175 that were down regulated. The genes involved in short chain length fatty acid metabolism were highly upregulated in the mutant strain. The genes encoding 3-hydroxybutyrate dehydrogenase were 5.8-fold upregulated and thus the gene was cloned, expressed and purified to reveal it can act on glyceraldehyde but not glycerol as a substrate.

Competition studies with fast-growing Rhizobium japonicum strains

1985 ◽  
Vol 31 (3) ◽  
pp. 220-223 ◽  
Author(s):  
Thomas J. McLoughlin ◽  
P. Ann Owens ◽  
Scott G. Alt
Keyword(s):  
Glycine Max ◽  
Host Range ◽  
Competitive Ability ◽  
Rhizobium Japonicum ◽  
Broad Host Range ◽  
Inoculum Level ◽  
Fast Growing ◽  
Slow Growing

The ability of eight fast-growing strains of Rhizobium japonicum to compete for nodule sites against two slow-growing strains of R. japonicum was measured using different input ratios (1:1, 1:10, and 10:1) on Glycine max cv. Peking and cv. Jacques 130 in growth pouches. The slow growers formed >60% of the nodules on cv. Peking even when the fast growers were added at a 10:1 ratio in their favor. We also measured the competitive ability of 10 fast-growing strains of R. japonicum, including these 8 strains, and ANU240 (a fast-growing broad host range strain) at two inoculum levels, 106 and 109 cells/seed on cv. Peking and cv. Jacques 130 in pots containing two midwestern soils which contained high numbers of indigenous rhizobia. In one soil, 3 of the 10 fast-growing strains occupied >60% of the nodules on cv. Peking at 109 inoculum level. No nodules were formed by the fast-growing strains on cv. Jacques 130 in any of the experiments.

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