GLUCOSE AND RIBOSE OXIDATION BY PSEUDOMONAS FRAGI

1963 ◽  
Vol 41 (4) ◽  
pp. 1023-1034
Author(s):  
M. Leroux ◽  
H. L. A. Tarr
Keyword(s):  
Dehydrogenase Activity ◽  
Gluconic Acid ◽  
Soluble Fraction ◽  
Particulate Fraction ◽  
Pseudomonas Fragi ◽  
Dehydrogenase Enzyme ◽  
Specific Activities

The action of soluble and particulate fractions of sonically disrupted cells of Pseudomonas fragi on glucose and ribose was investigated. It was shown that ribose is oxidized by the particulate fraction to ribono-γ-lactone, but not further, thus verifying previous work. Evidence is presented in support of the fact that oxidation of both glucose and ribose is carried out by a single dehydrogenase enzyme, and that this enzyme is largely present in the particulate fraction. The soluble fraction possessed a lactonase enzyme which was purified slightly. This enzyme hydrolyzed glucono-δ-lactone but not glucono-γ-lactone. The washed particulate possessed no such lactonase activity. The soluble fraction possessed only about 4% of the dehydrogenase activity of the particulate fraction. Both the dehydrogenase and lactonase specific activities were similar when the organism was cultured in glucose or ribose-containing medium. Attempts to show that glucose was degraded by a phosphorolytic mechanism or that gluconic acid was degraded further failed. These findings are consistent with the fact that P. fragi oxidizes glucose to glucono-δ-lactone, and that this lactone is hydrolyzed to gluconic acid by a lactonase enzyme. No serious attempt was made to study the specificity of these enzymes, but it was observed that crude unwashed particulate fractions oxidized both galactose and mannose.

GLUCOSE AND RIBOSE OXIDATION BY PSEUDOMONAS FRAGI

1963 ◽  
Vol 41 (1) ◽  
pp. 1023-1034 ◽  
Author(s):  
M. Leroux ◽  
H. L. A. Tarr
Keyword(s):  
Dehydrogenase Activity ◽  
Gluconic Acid ◽  
Soluble Fraction ◽  
Particulate Fraction ◽  
Pseudomonas Fragi ◽  
Dehydrogenase Enzyme ◽  
Specific Activities

The action of soluble and particulate fractions of sonically disrupted cells of Pseudomonas fragi on glucose and ribose was investigated. It was shown that ribose is oxidized by the particulate fraction to ribono-γ-lactone, but not further, thus verifying previous work. Evidence is presented in support of the fact that oxidation of both glucose and ribose is carried out by a single dehydrogenase enzyme, and that this enzyme is largely present in the particulate fraction. The soluble fraction possessed a lactonase enzyme which was purified slightly. This enzyme hydrolyzed glucono-δ-lactone but not glucono-γ-lactone. The washed particulate possessed no such lactonase activity. The soluble fraction possessed only about 4% of the dehydrogenase activity of the particulate fraction. Both the dehydrogenase and lactonase specific activities were similar when the organism was cultured in glucose or ribose-containing medium. Attempts to show that glucose was degraded by a phosphorolytic mechanism or that gluconic acid was degraded further failed. These findings are consistent with the fact that P. fragi oxidizes glucose to glucono-δ-lactone, and that this lactone is hydrolyzed to gluconic acid by a lactonase enzyme. No serious attempt was made to study the specificity of these enzymes, but it was observed that crude unwashed particulate fractions oxidized both galactose and mannose.

DEHYDROGENASES DURING POSTEMBRYONIG DEVELOPMENT OF TRIBOLIUM CONFUSUM DUVAL (COLEOPTERA): I. MALATE DEHYDROGENASE AND MALIC ENZYME IN THE PARTICULATE AND SOLUBLE FRACTIONS

1967 ◽  
Vol 45 (9) ◽  
pp. 1393-1400 ◽  
Author(s):  
Sital Moorjani ◽  
André Lemonde
Keyword(s):  
Dehydrogenase Activity ◽  
Malate Dehydrogenase ◽  
Malic Enzyme ◽  
Anaerobic Metabolism ◽  
Soluble Fraction ◽  
Larval Period ◽  
Tribolium Confusum ◽  
Sudden Increase ◽  
Kinetic Behavior ◽  
Soluble Fractions

Malate dehydrogenase and malic enzyme activities in the particulate (mitochondria) and soluble fraction have been determined in relation to the larval–pupal transformation of Tribolium confusum. The malate dehydrogenase activity in the soluble fraction follows a more or less inverse trend as compared with that in the particulate fraction. The malate dehydrogenase activity in the particulate and soluble fractions of the larva is attributed to different enzymes based on their electrophoretic mobility. A sudden increase in the activity of malate dehydrogenase in the soluble fraction at the end of the larval period is attributed to release of the enzyme from mitochondria by lysis. A further comparison of the larval particulate and pupal soluble malate dehydrogenase is made on the basis of their kinetic behavior. Malic enzyme is NADP-linked, although activity was also noted with NAD. The significance of the high activity of malic enzyme and malate dehydrogenase during pupation is discussed in relation to anaerobic metabolism.

Activation of Human Platelets Causes Post-translational Modifications to Cytoplasmic Dynein

1997 ◽  
Vol 78 (02) ◽  
pp. 910-918 ◽  
Author(s):  
Stephen W Rothwell ◽  
Valerie S Calvert
Keyword(s):  
Molecular Motors ◽  
Soluble Fraction ◽  
Cytoplasmic Dynein ◽  
Human Platelets ◽  
Particulate Fraction ◽  
Cortical Region ◽  
Transient Time ◽  
Post Translational Modifications ◽  
Dynein Intermediate Chain ◽  
Intermediate Chain

SummaryIn our studies of human platelets we have detected the presence of the molecular motors kinesin and dynein. Dynein is present at a concentration (0.8 μg/g tissue) that is approximately 1/3 the concentration reported for neuronal tissue. Immunofluorescence microscopy of resting platelets shows that, while platelet microtubules are arranged in coiled hoops forming the marginal band in the cortical region of the platelet, dynein is distributed in a pattern of punctate staining throughout the cytoplasm of the platelets. Fractionation of unactivated platelets shows that dynein partitions to the soluble fraction. Stimulation of platelets with thrombin, ADP or epinephrine causes a partial translocation of dynein from the soluble fraction to the particulate fraction with thrombin being the most efficient agent at promoting this shift. Dynein intermediate chain recovered in the soluble fraction of disrupted platelets following activation displays a transient, time-dependent phosphorylation. In contrast, dynein intermediate chain recovered in the particulate fraction shows decreased phosphorylation. These results indicate that human platelets contain a complex microtubule-based system of motor proteins that is an integral part of the physiological changes occurring during platelet activation.

MODE OF ATTACK ON PHENOL BY A MICROCOCCUS SP. ISOLATED FROM COIR RETS

1966 ◽  
Vol 12 (5) ◽  
pp. 1031-1039 ◽  
Author(s):  
N. P. Jayasankar ◽  
J. V. Bhat
Keyword(s):  
Ethyl Acetate ◽  
Aromatic Compounds ◽  
Soluble Fraction ◽  
Maximal Activity ◽  
Phenol Hydroxylase ◽  
Pseudomonas Fragi

Phenol enrichments of coir rets resulted in the isolation of Pseudomonas desmolytica, Pseudomonas fragi, Pseudomonas dacunhae, and Micrococcus varians. The inducible phenol hydroxylase of M. varians obtained in a crude form showed maximal activity at pH 7.5. Evidence was adduced to show that the ring-cleaving enzyme of M. varians was of the metapyrocatechase type. The M. varians strains when cultured in phenol medium elaborated a diffusible melanin-like pigment. Ethyl acetate soluble fraction of the pigment was identified as 3,4,3′,4′-tetrahydroxy diphenyl. The effect of certain aromatic compounds and copper binders on pigmentation was investigated.

scholarly journals The pathway of glycollate utilization in Chlorella pyrenoidosa

1970 ◽  
Vol 117 (5) ◽  
pp. 929-937 ◽  
Author(s):  
J. M. Lord ◽  
M. J. Merrett
Keyword(s):  
Soluble Fraction ◽  
Tricarboxylic Acid Cycle ◽  
Experimental Period ◽  
Chlorella Pyrenoidosa ◽  
Total Radioactivity ◽  
Tricarboxylic Acid ◽  
Short Term ◽  
Acid Cycle ◽  
Metabolic Sequence ◽  
Specific Activities

1. Exogenous glycollate was rapidly metabolized in both the light and the dark by photoautotrophically grown Chlorella pyrenoidosa. 2. The incorporation of 14C from [1-14C]glycollate by these cells was inhibited by the tricarboxylic acid-cycle inhibitors monofluoroacetate, diethylmalonate and arsenite, and also by α-hydroxypyrid-2-ylmethanesulphonate and isonicotinylhydrazine. 3. Short-term kinetic experiments showed over 80% of the total 14C present in the soluble fraction from the cells to be in glycine and serine after 10s. This percentage decreased with time whereas the percentage radioactivity in glycerate increased for up to 30s then remained steady. The percentage of the total radioactivity present in citrate increased over the experimental period. Malate was the only other tricarboxylic acid-cycle intermediate to become labelled. 4. The kinetic and inhibitor experiments supported the following pathway of glycollate incorporation: glycollate → glyoxylate → glycine → serine → hydroxypyruvate → glycerate → 3-phosphoglycerate → 2-phosphoglycerate → phosphoenolpyruvate → pyruvate → acetyl-CoA. 5. The specific activities of the enzymes catalysing this metabolic sequence in cell-free extracts were great enough to account for the observed rate of glycollate metabolism of 0.25μmol/h per mg dry wt. of cells in the light.

Characteristics of Phytochrome in Glutaraldehyde-Treated Maize Coleoptiles

1975 ◽  
Vol 2 (3) ◽  
pp. 281 ◽  
Author(s):  
R Yu
Keyword(s):  
Soluble Fraction ◽  
Red Light ◽  
Intracellular Distribution ◽  
Subcellular Fractions ◽  
Particulate Fraction ◽  
Cell Fractionation

Glutaraldehyde treatment was used to stabilize the in situ distribution of phytochrome at intervals during the course of phytochrome dark reactions. Total cellular phytochrome decreased in maize coleoptiles when they were returned to darkness and incubated after red irradiation. Photoreversibility was lost in both the soluble and particulate fractions, being faster in the particulate fraction. Glutaraldehyde treatment of coleoptiles immediately after irradiation inhibited loss of particulate phytochrome in the dark. When coleoptiles were irradiated with R/FR, i.e, red light (R, 660 nm) followed by far-red light (FR, 737 nm), and then incubated in the dark, the loss of particulate phytochrome was compensated for by an increase of phytochrome in the soluble fraction, resulting in negligible loss of total phytochrome. The phytochrome dark reactions in subcellular fractions of coleoptiles irradiated in vivo with R and R/FR and extracted in Mg2+-containing buffer were similar to those in corresponding subcellular fractions of coleoptiles treated with glutaraldehyde before cell fractionation. If the pattern of phytochrome dark reactions in subcellular fractions of R- and R/FR-irradiated coleoptiles treated with glutaraldehyde before cell fractionation truly reffects the in situ situation, this similarity suggests that the phytochrome distribution in subcellular fractions obtained by extraction in Mg2+-containing buffer of coleoptiles irradiated in vivo (without ghtaraldehyde treatment) also represents the intracellular distribution. This conclusion however cannot be extended to the distribution obtained following irradiation of Mg2+-containing non-cellular extracts.

Differences Between Cultured and Freshly Isolated Cyanobiont from Peltigera—Is there Symbiosis-Specific Regulation Of a Glucose Carrier?

1996 ◽  
Vol 28 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Robert Wastlhuber ◽  
Eckhard Loos
Keyword(s):  
Soluble Fraction ◽  
Phase System ◽  
Starch Phosphorylase ◽  
Two Phase ◽  
Prolonged Culture ◽  
Specific Activities ◽  
Specific Regulation ◽  
Enzymes Of Carbohydrate Metabolism ◽  
Glucose Carrier ◽  
Pool Sizes

AbstractThe cyanobiont (Nostoc) of the lichen Peltigera horizontalis was isolated using a procedure of repeated grinding, differential centrifugation and partitioning in an aqueous two-phase system of dextran/polyethylene glycol. A yield of 22% was calculated on the basis of chlorophyll recovery from the thallus. Freshly isolated Nostoc differed little from that kept in prolonged culture with respect to the relative activities of a number of enzymes of carbohydrate metabolism in the soluble fraction. However, much higher specific activities of the disproportionating transglycosylase and starch phosphorylase, higher intracellular concentrations of glucose, maltooligosaccharides and glycogen and a lower rate of glucose uptake were evidentin freshly isolated Nostoc. These activities and pool sizes, as well as CO2-fixation capability, stayed roughly constant for at least 5 h after isolation; glucose release, which is characteristic for the symbiotic Nostoc, dropped sharply within 1 h. These observations suggest the transport of glucose out of the cell, rather than that theactivities of cytoplasmic enzymes may bea point of early regulation during transition of Nostoc from the lichenized to the free-livingstate.

scholarly journals Pathways leading to and from serine during growth of Pseudomonas AM1 in C1 compounds or succinate

1970 ◽  
Vol 117 (3) ◽  
pp. 563-572 ◽  
Author(s):  
J. Heptinstall ◽  
J. R. Quayle
Keyword(s):  
Dehydrogenase Activity ◽  
Reductase Activity ◽  
Methanol Dehydrogenase ◽  
Wild Type ◽  
Hydroxypyruvate Reductase ◽  
Phosphoglycerate Dehydrogenase ◽  
Specific Activities ◽  
Phenazine Methosulphate ◽  
Serine Biosynthesis ◽  
Enrichment Step

1. The following enzymes of the phosphorylated pathway of serine biosynthesis have been found in methanol- and succinate-grown Pseudomonas AM1: phosphoglycerate dehydrogenase, phosphoserine-α-oxoglutarate aminotransferase and phosphoserine phosphohydrolase. Their specific activities were similar in the organism grown on either substrate. 2. A procedure for preparation of auxotrophic mutants of Pseudomonas AM1 is described involving N-methyl-N′-nitro-N-nitrosoguanidine as mutagen and a penicillin enrichment step. 3. A mutant, M-15A, has been isolated that is unable to grow on methanol and that lacks phenazine methosulphate-linked methanol dehydrogenase. The mutant is able to grow on methylamine, showing that the amine is not oxidized by way of methanol. 4. Loss of methanol dehydrogenase activity in mutant M-15A led to loss of phenazine methosulphate-linked formaldehyde dehydrogenase activity showing that the same enzyme is probably responsible for both activities. 5. A mutant, 20B-L, has been isolated that cannot grow on any C1 compound tested but can grow on succinate. 6. Mutant 20B-L lacks hydroxypyruvate reductase, and revertants that regained the ability to grow on methanol, methylamine and formate contained hydroxypyruvate reductase activity at specific activities similar to that of the wild-type organism. This shows that hydroxypyruvate reductase is necessary for growth on methanol, methylamine and formate but not for growth on succinate. 7. The results suggest that during growth of Pseudomonas AM1 on C1 compounds, serine is converted into 3-phosphoglycerate by a non-phosphorylated pathway, whereas during growth on succinate, phosphoglycerate is converted into serine by a phosphorylated pathway.

Benzyladenine accelerates chloroplast differentiation and stimulates photosynthetic enzyme activity in cucumber cotyledons

1974 ◽  
Vol 52 (12) ◽  
pp. 2581-2586 ◽  
Author(s):  
B. M. R. Harvey ◽  
B. C. Lu ◽  
R. A. Fletcher
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Enzyme Activities ◽  
Membrane System ◽  
Structural Differentiation ◽  
Specific Activities ◽  
Cucumber Cotyledons ◽  
Ribulose Diphosphate Carboxylase ◽  
Stimulation Of

The chloroplasts of etiolated cucumber cotyledons had crystalline prolamellar bodies, whereas those treated with benzyladenine (BA) have a well-developed plastid membrane system. After 4 h of exposure to light, grana were formed in the chloroplasts of BA-treated cotyledons but not in the controls. The specific activities of ribulose 1,5-diphosphate carboxylase, and NADP-dependent glyceraldehyde 3-phosphate dehydrogenase increased 75 and 50% respectively during BA treatment in the dark, while there was little change in the controls. On exposure to light, enzyme activities increased in both control and BA-treated cotyledons. Inhibitors of protein synthesis eliminated the BA stimulation of ribulose diphosphate carboxylase but had little effect on the BA stimulation of NADP-dependent glyceraldehyde 3-phosphate dehydrogenase activity. This study indicates that BA stimulates structural differentiation of the chloroplast and enhances activities of photosynthetic enzymes, even in the dark.

scholarly journals Tricarboxylic acid-cycle and related enzymes in restricted facultative methylotrophs

1975 ◽  
Vol 148 (3) ◽  
pp. 505-511 ◽  
Author(s):  
J Colby ◽  
L J Zatman
Keyword(s):  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Isocitrate Dehydrogenase ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Methylotrophic Bacteria ◽  
Acid Cycle ◽  
Oxoglutarate Dehydrogenase ◽  
Specific Activities ◽  
Succinyl Coa Synthetase

The isolation is described of pure cultures of three non-methane-utilizing methylotrophic bacteria which, together with the previously described Bacillus PM6, have a very limited range of growth substrates; these organisms are designated “restricted facultative’ methylotrophs. Two of these isolates, W6A and W3A1, grow only on glucose out of 50 non-C1 compounds tested, whereas the third isolate S2A1 and Bacillus PM6 grow on betaine, glucose, gluconate, alanine, glutamate, citrate and nutrient agar, but not on any of a further 56 non-C1 compounds. Crude sonic extracts of trimethylamine-grown and glucose-grown W6A and W3A1 isolates, and of trimethylamine-grown C2A1 (an obligate methylotroph) contain (i) no detectable 2-oxogltarate dehydrogenase activity, (ii) very low or zero specific activities of succinate dehydrogenase and succinyl-CoA synthetase and (iii) NAD+-dependent isocitrate dehydrogenase activity. Extracts of trimethylamine-grown PM6 and S2A1 methylotrophs have (i) very low 2-oxoglutarate dehydrogenase specific activities, (ii) comparatively high specific activities of succinate dehydrogenase, malate dehydrogenase and succinyl-CoA synthetase and (iii) NADP+-dependent isocitrate dehydrogenase activity but no NAD+-dependent isocitrate dehydrogenase activity. The activities of most of these enzymes are increased during growth on glucose, alanine, glutamate or citrate, but only very low 2-oxoglutarate dehydrogenase activities are present under all growth conditions. The restricted facultative methylotrophs grow on certain non-C1 compounds in the absence of 2-oxoglutarate dehydrogenase and, in some cases, of other enzymes of the tricarboxylic acid cycle; these lesions cannot therefore be the sole cause of obligate methylotrophy.

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