scholarly journals The metabolism of aged seeds. The involvement of the pentose phosphate pathway in respiration in germinating rye grains of various ages

2014 ◽  
Vol 61 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Kazimierz Zalewski
Keyword(s):  
Dehydrogenase Activity ◽  
Pentose Phosphate Pathway ◽  
Growth Analysis ◽  
Krebs Cycle ◽  
Pentose Phosphate ◽  
Seed Vigor ◽  
Winter Rye ◽  
Oxidation Of Glucose ◽  
Aged Seeds

Winter rye grains from different harvest years (having distinctly different viabilities) were studied in terms of germination, total dehydrogenase activity and growth analysis. Reduction of seed vigor and viability was accompanied by a decrease in the intensity of embryo respiration during germination. The use of (1-<sup>14</sup>C) glucose and (6-<sup>14</sup>C) glucose showed that germinating rye embryos catabolize glucose through glycolysis, Krebs cycle and the pentose phosphate pathway. It was also shown that the C<sub>6</sub>/C<sub>1</sub> ratio in respiring embryos initially increased during the first 48 hours of germination, then dropped, which suggests a mounting contribution of the PP pathway to the overall cotabolism. The oxidation of glucose in, embryos from the most deteriorated grains proceeded through glycolysis and Krebs cycle only.

Improving salinity resilience in Swertia chirayita clonal line with Lactobacillus plantarum

2016 ◽  
Vol 96 (1) ◽  
pp. 117-127 ◽  
Author(s):  
Susanna Phoboo ◽  
Dipayan Sarkar ◽  
Prasanta C. Bhowmik ◽  
Pramod Kumar Jha ◽  
Kalidas Shetty
Keyword(s):  
Dehydrogenase Activity ◽  
Lactobacillus Plantarum ◽  
Salinity Stress ◽  
Pentose Phosphate Pathway ◽  
Krebs Cycle ◽  
Defense Responses ◽  
Pentose Phosphate ◽  
Clonal Line ◽  
Swertia Chirayita ◽  
Stimulation Of

Plants defense responses to abiotic stresses, including salinity stress, involve stimulation of defense related pathways such as biosynthesis of secondary metabolites and induction of endogenous antioxidant enzyme responses. In the present study, a single seed origin clonal line of Swertia chirayita inoculated with Lactobacillus plantarum (LP) was grown under different salinity levels. Control had no LP inoculation. S. chirayita inoculated with LP showed higher accumulation of proline, low proline dehydrogenase activity, up-regulation of pentose phosphate pathway, down-regulation of succinate dehydrogenase activity (Krebs cycle) and low total phenolic content with increased salt concentrations. In comparison, S. chirayita without LP adopted a different biochemical mechanism to counter salt stress (NaCl) by up-regulating both pentose phosphate pathway and Krebs cycle along with stimulation of phenolic biosynthesis. Guaiacol peroxidase (GPX) activity increased with and without LP treatment in response to increasing concentrations of salt. These results indicate that S. chirayita inoculated with LP exhibits a greater salinity stress tolerance than S. chirayita without LP by adopting a more energy efficient defense responses and potentially efficiently partitioning carbon flux between primary and secondary metabolism to counter salt induced oxidative stress.

scholarly journals YvcK of Bacillus subtilis is required for a normal cell shape and for growth on Krebs cycle intermediates and substrates of the pentose phosphate pathway

Microbiology ◽  
2005 ◽  
Vol 151 (11) ◽  
pp. 3777-3791 ◽  
Author(s):  
Boris Görke ◽  
Elodie Foulquier ◽  
Anne Galinier
Keyword(s):  
Bacillus Subtilis ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Carbon Sources ◽  
Krebs Cycle ◽  
Normal Growth ◽  
Central Carbon Metabolism ◽  
Pentose Phosphate ◽  
Homologous Protein ◽  
Krebs Cycle Intermediates

The HPr-like protein Crh has so far been detected only in the bacillus group of bacteria. In Bacillus subtilis, its gene is part of an operon composed of six ORFs, three of which exhibit strong similarity to genes of unknown function present in many bacteria. The promoter of the operon was determined and found to be constitutively active. A deletion analysis revealed that gene yvcK, encoded by this operon, is essential for growth on Krebs cycle intermediates and on carbon sources metabolized via the pentose phosphate pathway. In addition, cells lacking YvcK acquired media-dependent filamentous or L-shape-like aberrant morphologies. The presence of high magnesium concentrations restored normal growth and cell morphology. Furthermore, suppressor mutants cured from these growth defects appeared spontaneously with a high frequency. Such suppressing mutations were identified in a transposon mutagenesis screen and found to reside in seven different loci. Two of them mapped in genes of central carbon metabolism, including zwf, which encodes glucose-6-phosphate dehydrogenase and cggR, the product of which regulates the synthesis of glyceraldehyde-3-phosphate dehydrogenase. All these results suggest that YvcK has an important role in carbon metabolism, probably in gluconeogenesis required for the synthesis of cell wall precursor molecules. Interestingly, the Escherichia coli homologous protein, YbhK, can substitute for YvcK in B. subtilis, suggesting that the two proteins have been functionally conserved in these different bacteria.

A study of the relationship between seed dormancy and pentose phosphate pathway activity in Avena fatua

1983 ◽  
Vol 61 (3) ◽  
pp. 667-670 ◽  
Author(s):  
E. P. Fuerst ◽  
M. K. Upadhyaya ◽  
G. M. Simpson ◽  
J. M. Naylor ◽  
S. W. Adkins
Keyword(s):  
Seed Dormancy ◽  
Pentose Phosphate Pathway ◽  
Krebs Cycle ◽  
Pure Line ◽  
Pentose Phosphate ◽  
Avena Fatua ◽  
Wild Oats ◽  
Gibberellin Treatment ◽  
The Relationship ◽  
Increased Activity

The hypothesis that loss of seed dormancy is associated with an increased activity of the pentose phosphate pathway (PPP) relative to glycolysis and the Krebs cycle was tested. The PPP activity was monitored by measuring the C6/C1 ratio in embryos excised from incubated caryopses of two genetically pure nondormant (ND) lines and in three dormant (D) lines of Avena fatua L., the wild oat. The C6/C1 ratios of all lines were similar at the commencement of incubation. In the two ND lines the ratio increased steadily prior to and during emergence of the radicle. In the three D lines the ratio increased during the first 24 h and then remained almost constant; there was no germination. When gibberellin treatment was used to overcome dormancy in the D lines, the C6/C1 ratio increased during the first 24 h in two of the lines and continued to increase parallel to germination in a manner similar to normal germination in ND lines. In the third D line, despite loss of dormancy from gibberellin treatment, the ratio did not increase after 24 h. Loss of dormancy during dry storage of seeds of a D-type pure line was accompanied by an increase in the C6/C1 ratio, as measured in freshly imbibed seeds. This indicates a decreased activity of the PPP relative to glycolysis and the Krebs cycle. These findings are contrary to Roberts's hypothesis that loss of dormancy in wild oats is associated with a relative decrease in the C6/C1 ratio.

scholarly journals Transcriptional and Metabolic Responses of Bacillus subtilis to the Availability of Organic Acids: Transcription Regulation Is Important but Not Sufficient To Account for Metabolic Adaptation

2006 ◽  
Vol 73 (2) ◽  
pp. 499-507 ◽  
Author(s):  
Oliver Schilling ◽  
Oliver Frick ◽  
Christina Herzberg ◽  
Armin Ehrenreich ◽  
Elmar Heinzle ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Organic Acids ◽  
Pentose Phosphate Pathway ◽  
Metabolic Regulation ◽  
Metabolic Flux ◽  
Krebs Cycle ◽  
Pentose Phosphate ◽  
Metabolic Adaptation ◽  
Acetyl Coa ◽  
Additional Level

ABSTRACT The soil bacterium Bacillus subtilis can use sugars or organic acids as sources of carbon and energy. These nutrients are metabolized by glycolysis, the pentose phosphate pathway, and the Krebs citric acid cycle. While the response of B. subtilis to the availability of sugars is well understood, much less is known about the changes in metabolism if organic acids feeding into the Krebs cycle are provided. If B. subtilis is supplied with succinate and glutamate in addition to glucose, the cells readjust their metabolism as determined by transcriptome and metabolic flux analyses. The portion of glucose-6-phosphate that feeds into the pentose phosphate pathway is significantly increased in the presence of organic acids. Similarly, important changes were detected at the level of pyruvate and acetyl coenzyme A (acetyl-CoA). In the presence of organic acids, oxaloacetate formation is strongly reduced, whereas the formation of lactate is significantly increased. The alsSD operon required for acetoin formation is strongly induced in the presence of organic acids; however, no acetoin formation was observed. The recently discovered phosphorylation of acetolactate decarboxylase may provide an additional level of control of metabolism. In the presence of organic acids, both types of analyses suggest that acetyl-CoA was catabolized to acetate rather than used for feeding the Krebs cycle. Our results suggest that future work has to concentrate on the posttranslational mechanisms of metabolic regulation.

Effects of insulin, glucocorticoids and thyroid hormones on the activities of key enzymes of glycolysis, glutaminolysis, the pentose-phosphate pathway and the Krebs cycle in rat macrophages

1992 ◽  
Vol 135 (2) ◽  
pp. 213-219 ◽  
Author(s):  
L. F. B. P. Costa Rosa ◽  
Y. Cury ◽  
R. Curi
Keyword(s):  
Thyroid Hormones ◽  
Pentose Phosphate Pathway ◽  
Culture Medium ◽  
Citrate Synthase ◽  
Inflammatory Responses ◽  
Krebs Cycle ◽  
Pentose Phosphate ◽  
Macrophage Phagocytosis ◽  
And Function ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT In the present study the effects of insulin, glucocorticoids and thyroid hormones on macrophage metabolism and function were investigated. The maximum activities of hexokinase, glucose-6-phosphate dehydrogenase, glutaminase and citrate synthase were determined in macrophages obtained from hormonetreated rats and those cultured for a period of 48 h in the presence of hormones. Macrophage phagocytosis was markedly inhibited by dexamethasone and thyroid hormones, remaining unchanged when insulin was added to the culture medium, however. The changes in the enzyme activities caused by hormone treatments of the rats were very similar to those found in culture. Insulin enhanced citrate synthase and hexokinase activities and diminished those of glutaminase and glucose-6-phosphate dehydrogenase. Dexamethasone had a similar effect except on glucose6-phosphate dehydrogenase. The addition of thyroid hormones to the culture medium raised the activities of glutaminase and hexokinase and reduced that of citrate synthase. The results presented support the suggestion that the effects of insulin, glucocorticoids and thyroid hormones on immune and inflammatory responses could well be mediated through changes in macrophage metabolism.. Journal of Endocrinology (1992) 135, 213–219

scholarly journals Metabolism of aged seeds. Changes in rye embryo polyribosomes during seed aging

2014 ◽  
Vol 61 (3-4) ◽  
pp. 369-379
Author(s):  
Kazimierz Zalewski
Keyword(s):  
Dehydrogenase Activity ◽  
Ribosomal Proteins ◽  
Control Sample ◽  
Electrophoretic Analysis ◽  
Winter Rye ◽  
Control Embryo ◽  
Ribonucleic Acids ◽  
Seed Aging ◽  
Almost All ◽  
Aged Seeds

Germination, total dehydrogenase activity, ribosomal proteins and ribonucleic acids of embryos obtained from winter rye harvested in different years and of distinctly differing viability were studied. Diminishing viability was accompanied by declines in the amount of ribosome-bound mRNA and a drop in the intensity of its synthesis during germination. Electrophoretic analysis of control embryo (fully viable) ribosome proteins revealed 55 different bands: 10 acidic and 45 basic. The embryos of aged seeds had 43 different bands of which 8 were acidic, 35 basic and almost all of which had an altered electrophoretic mobility as compared with the control sample. As aging progressed, the percentages of lysine, histidine and arginine increased while those of tyrosine, methionine, proline and serine decreased.

Enzyme Activities in Prickly Sida(Sida spinosa)Seeds of Different Developmental Stages

Weed Science ◽  
1978 ◽  
Vol 26 (4) ◽  
pp. 349-351 ◽  
Author(s):  
E. W. Smith ◽  
B. J. Reger ◽  
G. H. Egley
Keyword(s):  
Dehydrogenase Activity ◽  
Pentose Phosphate Pathway ◽  
Isocitrate Dehydrogenase ◽  
Enzyme Activities ◽  
Developmental Stages ◽  
Pentose Phosphate ◽  
Sida Spinosa ◽  
Prickly Sida ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Days After Anthesis

Key metabolic enzymes and germination were studied in developing and mature, dormant and nondormant prickly sida(Sida spinosaL.) seeds. Isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, fructose-1,6-diphosphatase, and phosphofructokinase activities were determined in developing and mature prickly sida seeds. Developing seeds less than 7 days after anthesis and at 17 days or greater after anthesis were unable to germinate. The 7-day-old seeds lacked all but fructose-1,6-diphosphatase activity. The 17-day-old seeds demonstrated all enzyme activities but failed to germinate because dehydration had occurred and seeds were unable to imbibe sufficient water without an afterripening period. Comparison of enzyme activities of dormant and nondormant seeds on incubation showed that only glucose-6-phosphate dehydrogenase was considerably different within the first 8 h of incubation. Nondormant seeds had considerable glucose-6-phosphate dehydrogenase activity before germination (radical protrusion at 8 h), suggesting an active pentose phosphate pathway.

scholarly journals Glucose metabolism via the pentose phosphate pathway, glycolysis and Krebs cycle in an orthotopic mouse model of human brain tumors

2012 ◽  
Vol 25 (10) ◽  
pp. 1177-1186 ◽  
Author(s):  
Isaac Marin-Valencia ◽  
Steve K. Cho ◽  
Dinesh Rakheja ◽  
Kimmo J. Hatanpaa ◽  
Payal Kapur ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Brain Tumors ◽  
Mouse Model ◽  
Human Brain ◽  
Pentose Phosphate Pathway ◽  
Krebs Cycle ◽  
Pentose Phosphate ◽  
Orthotopic Mouse Model ◽  
Human Brain Tumors

scholarly journals Measurement of pentose phosphate-pathway activity in a single incubation with [1,6-13C2,6,6-2H2]glucose

1994 ◽  
Vol 302 (1) ◽  
pp. 31-38 ◽  
Author(s):  
B D Ross ◽  
P B Kingsley ◽  
O Ben-Yoseph
Keyword(s):  
Pentose Phosphate Pathway ◽  
Cultured Cells ◽  
Krebs Cycle ◽  
Pentose Phosphate ◽  
Repeated Measurements ◽  
Co2 Production ◽  
Spectrometric Analysis ◽  
14Co2 Production ◽  
Single Set

The isotopically substituted molecule D-[1,6-13C2,6,6-2H2]glucose is introduced for measuring the relative activities of the pentose phosphate pathway (PPP) and glycolysis in a single incubation. PPP activity in cultured cells was determined by gas chromatography/mass spectrometric analysis of lactate produced by cells incubated with [1,6-13C2,6,6-2H2]glucose. Two other isotopes, [1,5,6-13C3]glucose and [6-13C,1,6,6-2H3]glucose, were not satisfactory for measurements of this activity. This method has four advantages over the traditional one in which 14CO2 production from [1-14C]glucose and [6-14C]glucose is compared: (1) repeated measurements can be made on a single set of cells, (2) only a single incubation is required, (3) extensive CO2 production by Krebs-cycle activity does not interfere with the measurements and (4) it is not necessary to measure the amount of glucose consumed in order to calculate relative activities of the PPP and glycolysis. Preliminary observation indicates that rat brain PPP activity may be measured in vivo with [1,6-13C2,6,6-2H2]glucose when combined with microdialysis techniques.

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