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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biosynthesis of neutral lipids in Mycobacterium smegmatis was studied using cell free extracts. Maximum neutral lipid production was obtained when the reaction mixture (400 microliter) consisted of 0.25 M potassium phosphate buffer (pH 7.5), 0.125 mM oleoyl-CoA, 3.75 mM sn-glycerol-3-P, 10 mM MgCl2 and 1.85 mg bovine serum albumin. No magnesium dependency for the acylation of sn-glycerol-3-P was observed. A slight stabilizing effect seemed to occur due to this ion. The enzyme phosphatidate phosphohydrolase, on the other hand, was shown to be magnesium dependent. The activity of this enzyme also appeared to be stimulated by high concentration (0.75 to 1.25 mM) of ATP which enhanced lipid formation at all concentrations tested (0.25 to 3.75 mM). A heat-stable protective factor having a molecular weight less than 16 000 which caused a stimulatory effect on sn-glycerol 3-phosphate acyltransferase activity was found in the cell-free extracts. Preliminary experiments suggest that the factor might be polysaccharide in nature.
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PMID:Neutral lipid biosynthesis in Mycobacterium smegmatis. 2 Jan 50

Contrary to the the tubercle bacilli (H37Ra, BCG), Mycobacterium phlei, grown on Sauton medium, formed the NAD+ dependent dehydrogenases that catalyse the oxidation of ribitol, sorbitol and mannitol. These enzymes were separated by chromatography on DEAE-cellulose and Sephadex G-200. In the present work we have principally studied the ribitol dehydrogenase. All the experiments for induction of the ribitol dehydrogenase in H37Ra or BCG were negative; whereas after the adaptation of M. phlei to ribitol, the specific activity of this enzyme increased in the supernatants more than 100 per cent. The ribitol dehydrogenase of M. phlei reduced NAD+ not only in the presence of ribitol but also (though to a lesser extent) in the presence of erythritol and glycerol. Other properties studied concerning this enzyme and the reaction it catalyses were: pH dependence, equilibrium constant, Km and sensitivity towards the inhibitors of the thiol groups.
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PMID:[Polyol dehydrogenases in mycobacteria (author's transl)]. 2 46

A biologically active material (fraction "S") is isolated from cultures of scotochromogenic mycobacteria. Mycobacterium tuberculosis, or Mycobacterium bovis by disrupting the cells, sedimentation through 2.2 M sucrose, and ultrafiltration. The fraction "S" induces the modification of tubercle bacilli into non acid-fast bacteria forming smooth colonies on nutritive glycerol agar within 24-36 h of incubation. Three new phenotypes are thus obtained; two proved to be stable upon subculturing. Frequently the phenomenon occurs with a very large part of the Koch's bacillus population exposed to the inducing agent effect. It can be reproduced with crude preparations of DNA obtained from the fraction "S." It is inhibited by concanavalin A. The observed modification does not correspond to a transfer of characteristics of the inducing agent from the donor mycobacteria; furthermore it can be manifested even in the strain used for the preparation of the fraction "S."
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PMID:[Transmissible modification induced in Mycobacterium tuberculosis and Mycobacterium bovis in vitro]. 11 93

Glucose metabolism in Mycobacterium smegmatis was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Glucose is oxidized in this organism mainly through the Embden-Meyerhof-Parnas pathway, irrespective of the carbon source used for growth. The pentose phosphate pathway plays only a minor role and its extent depends on the carbon source used for growth. Enzymes of glycolytic and oxidative pathways were detected in cells grown on glucose, glycerol, or pyruvate but enzymes of the Entner-Duodroff pathway could be detected only in glucose-grown cells. Labeled acetate is utilized by cells cultured on glucose, glycerol, and pyruvate. In all cases more of C1 of acetate was converted to CO2 while incorporation into cellular constituents was maximum from C2 of acetate.
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PMID:Pathways of glucose catabolism in Mycobacterium smegmatis. 18 6

The intracellular concentration of cyclic AMP reached a maximum in 3.5-day old cultures of Mycobacterium smegmatis grown in the presence of glycerol as the main source of carbon. Glucose-grown cells exhibited decreased cyclic AMP levels at all stages of growth. When M. smegmatis cells were incubated with various metabolites, pyruvate increased whereas glucose, ctric acid, succinic acid and lactic acid decreased intracellular cyclic AMP levels. No cyclic AMP was detected in the incubation medium. The presence of a cyclic AMP-binding protein was demonstrated in cell-free extracts of M. smegmatis.
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PMID:Metabolism of cyclic AMP in non-pathogenic Mycobacterium smegmatis. 21 15

Seven Mycobacterium strains were grown statically on salts-glycerol-asparagine (Sauton) or on salts-glucose-glutamate (Sym) media. At desired time of incubation, the bacteria were washed with water, disintegrated with powdered corundum and in resulting cell-free extracts L-asparaginase activity was determined by the Conway method. The majority of experiments were performed on M. phlei which exhibited considerable rise in L-asparaginase activity with increasing age of the culture. This change did not occur on Sym medium because of Zn2+, which proved to abolish the effect of the enzyme induction in vivo but did not inhibit the activity in vitro. Addition of rifampicin to Sauton culture media resulted in a low enzyme level. Exogenous asparagine and glycerol were not indispensable for the enzyme synthesis and could be replaced by glutamate and glucose, respectively.
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PMID:L-asparaginase activity of Mycobacterium phlei under various growth conditions. 24 89

Two tuberculin-positive baboons in a primate colony were found to have grossly visible tuberculous lesions in the liver, spleen, lung, and mediastinal lymph nodes on necropsy. Results of histopathologic examination of the tissues showed granulomas with Langhans giant cells. An acid-fast organism was isolated from tissues of each baboon; the isolates were identified as Mycobacterium bovis by being negative for niacin production and nitrate reduction and by their susceptibility to thiophen-2-carbosylic acid hydrazide and to 5% glycerol.
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PMID:Mycobacterium bovis infection in baboons (Papio papio). 32 36

Contrary to the tubercle Bacilli (H37Ra, BCG), Mycobacterium phlei has a ribitol-NAD dehydrogenase (that also oxidizes, although to a lesser extent, erythritol and glycerol). This difference is observed with the Bacteria grown on Sauton's medium, as well as after their adaptation to ribitol. The extracts of all these Mycobacteria reduce, NADP in the presence of glycerol, ribitol or erythritol, though very slowly.
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PMID:[Enzymatic differences in mycobacteria. Ribitol dehydrogenase]. 40 36

Cells of Mycobacterium fortuitum kept in 0.85% saline solution containing 0.1% Tween 80 (without glycerol) survive for a long time. In glycerol-enriched medium, they continue to lose their viability at a high rate; after 71 days of exposure the percentage of survival as indicated by colony formation and respiratory and dehydrogenase activities is lower than 1%. Surviving cells starved in medium without glycerol revealed unchanged sensitivity to streptomycin, p-aminosalicylic acid, and isoniazid.
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PMID:Effect of glycerol on viability and other properties of starved Mycobacterium fortuitum. 47 41

Intact cells obtained from Mycobacterium scrofulaceum as well as from mycobacterial strains M.A6 and M.R56 isolated respectively from leprous tissues of armadillo and rat leproma and grown with glycerol as the oxidizable substrate catalyzed complete oxidation of formate. The stoichiometry of formate oxidase system yielded a value of 2 mol of CO2 produced per mole of O2 or per 2 moles of formate consumed. Cell-free preparations from these three strains of mycobacteria contained formate dehydrogenase which was associated exclusively in the particulate fraction. Formate oxidation was markedly stimulated by small amounts of selenite and molybdate added together. Formate-reduced minus oxidized difference spectra disclosed cytochromes of the b type while spectral evidence did not suggest the existence of cytochromes a or c components. The effect of 2-N-heptyl-4-hydroxyquinoline-N-oxide on the redox state of cytochromes indicated that formate oxidation was mediated by cytochrome b with absorption maximum of 556 nm and not of 562 nm.
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PMID:Oxidation of formate by mycobacteria of the scrofulaceum group. 74 15


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