Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A particulate fraction prepared from Mycobacterium phlei grown in a metal-deficient medium exhibited a greatly reduced activity of stearoyl-CoA desaturase compared to that from normally grown cells. Metal deficiency, however, had no effect on the FAD-dependent NADPH-cytochrome C reductase activity, which has been suggested to participate in the desaturation process. When the cells were grown in the deficient medium supplemented with both Fe2+ and Mg2+, the desaturase activity was restored to the normal level. Supplementation with Mg2+ alone promoted growth but did not restore the desaturase activity, whereas Fe2+ alone did cause a significant restoration. Among the various metal ions tested, only Fe2+ and Fe3+ enhanced the formation of desaturase activity in the deficient medium. When added to the assay medium in vitro, Fe2+ and Fe3+ did not stimulate the desaturase activity of the particulate fraction from the deficient cells. Cultivation in the metal-deficient medium had essentially no effect on the levels of cytochromes in the particulate fraction, but dramatically decreased the non-heme iron content and the amount of a high-spin ferric species exhibiting an ESR signal at g=4.3. No labile sulfur could be detected in the normal or metal-deficient particulate fractions. It is concluded that the presence of iron ions in the culture medium is necessary for the synthesis and/or assembly of the terminal portion of the desaturase system.
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PMID:Effect of metal ions in the culture medium on the stearoyl-coenzyme A desaturase activity of Mycobacterium phlei. 0 87

A iron-chelating monohydroxamate was isolated from cultures of Mycobacterium avium grown on an iron-limiting medium. The hydroxyamate metabolite was characterized by chemical degradation and spectral measurements as L-alpha-asparaginyl-L-alpha-(N-hydroxy)-asparagine.
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PMID:Iron-chelating compound from Mycobacterium avium. 18 94

Streptococcus faecalis contains a single superoxide dismutase that has been purified to homogeneity with a 55% yield. This enzyme has a molecular weight of 45,000 and is composed of two subunits of equal size. It contains 1.3 atoms of manganese per molecule. Its amino acid composition was determined and is compared with that for the superoxide dismutases from Escherichia coli, Streptococcus mutans, and Mycobacterium lepraemurium. When used as an antigen in rabbits, the S. faecalis enzyme elicited the formation of a precipitating and inhibiting antibody. This antibody cross-reacted with the superoxide dismutase present in another strain of S. faecalis, but neither inhibited nor precipitated the superoxide dismutases in a wide range of other bacteria, including several other streptococci, such as S. pyogenes, S. pneumoniae, and S. lactis. The inhibiting antibody was used to suppress the superoxide dismutase activity present in cell extracts of S. faecalis and thus allow the demonstration that 17% of the total oxygen consumption by such extracts, in the presence of reduced nicotinamide adenine dinucleotide, was associated with the production of O(2) (-). A variety of bacterial species were surveyed for their content of superoxide dismutases. The iron-containing enzyme was distinguished from the manganese-containing enzyme through the use of H(2)O(2), which inactivates the former more readily than the latter. Some of the bacteria appeared to contain only the iron enzyme, others only the manganese enzyme, and still others both. Indeed, some had multiple, electrophoretically distinct superoxide dismutases in both categories. There was no discernible absolute relationship between the types of superoxide dismutases in a particular organism and their Gram-stain reaction.
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PMID:Superoxide dismutase and oxygen metabolism in Streptococcus faecalis and comparisons with other organisms. 20 36

Peroxidase from Mycobacterium tuberculosis H37Rv was purified to homogeneity. The homogeneous protein exhibits catalase and Y (Youatt's)-enzyme activities in addition to peroxidase activity. Further confirmation that the three activities are due to a single enzyme was accomplished by other criteria, such as differential thermal inactivation, sensitivity to different inhibitors, and co-purification. The Y enzyme (peroxidase) was separated from NADase (NAD+ glycohydrolase) inhibitor by gel filtration on Sephadex G-200. The molecular weights of peroxidase and NADase inhibitor, as determined by gel filtration, are 240000 and 98000 respectively. The Y enzyme shows two Km values for both isoniazid (isonicotinic acid hydrazide) and NAD at low and high concentrations. Analysis of the data by Hill plots revealed that the enzyme has one binding site at lower substrate concentrations and more than one at higher substrate concentration. The enzyme contains 6g-atoms of iron/mol. Highly purified preparations of peroxidases from different sources catalyse the Y-enzyme reaction, suggesting that the nature of the reaction may be a peroxidatic oxidation of isoniazid. Moreover, the Y-enzyme reaction is enhanced by O2. Isoniazid-resistant mutants do not exhibit Y-enzyme, peroxidase or catalase activities, and do not take up isoniazid. The Y-enzyme reaction is therefore implicated in the uptake of the drug.
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PMID:The purification and properties of peroxidase in Mycobacterium tuberculosis H37Rv and its possible role in the mechanism of action of isonicotinic acid hydrazide. 24 21

Quantitative determination of the elements potassium, sodium, manganese, magnesium, iron, cobalt and zinc was performed in mycobacteria by neutron activation analysis. Mycobacterium phlei ATCC 19 249 at different phase of growth (4, 8, 13, 23 and 37 days old cultures), and 14 days old Mycobacterium bovis BCG cultures and uninoculated semi-synthetic Sauton culture media were examined. The elements studied could be divided into three groups; sodium, potassium and magnesium could be regarded as major, iron as minor, and zinc, manganese and cobalt as trace elements. M. phlei contained, with the exception of zinc, higher amounts of elements than M. bovis. Other metals (aluminium, antimony, rubidium) could also be detected.
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PMID:Quantitation of seven elements in Mycobacterium phlei and Mycobacterium bovis by neutron activation analysis. 34 56

The enhancement by exogenous ferric iron, both systemic and local, of the infectivity of 120 strains of bacteria, representing 17 genera, was measured in the skin of guinea-pigs. Systemic iron enhanced only 23% of 115 strains, and local iron 49% of 71 strains. Systemic iron, by an apparently anti-inflammatory action, depressed the size of lesions produced by 27 of the non-enhanced strains from nine of the genera tested. For most strains, the degree of enhancement was small, ranging from 2- to 8-fold, and often evident only with the more effective local iron; among these were some near-saprophytes like Mycobacterium phlei, M. smegmatis, Bacillus cereus and Clostridium bifermentans. Substantial enhancement, from 14- to 50-fold, was observed with the more pathogenic among the strains tested: namely BCG, Corynebacterium ovis, C. murium, Listeria monocytogenes, Erysipelothrix rhusiopathiae, Cl. perfringens, Cl. septicum, Cl. oedematiens, and some strains of Klebsiella spp., Proteus spp. and Aeromonas hydrophila. The enhancement of BCG by a single dose of iron given locally with the inoculum was only feebly manifest after 7 days, but substantial after 14--19 days, indicating the decisive effect of interference with an early humoral defence on the establishment of chronic infection some time later. Insofar as guinea-pigs whose antibacterial defences are lowered by substantial amounts of exogenous iron in the circulation represent human subjects at risk of infection because of clinical states characterised by excess of available iron, the results of the survey suggest that only a minority among the environmental bacteria can take advantage of the decreased resistance associated with such states; but that this minority is likely to include the more virulent strains in the environment.
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PMID:The variable response of bacteria to excess ferric iron in host tissues. 37 34

Antigen-specific type II interferon was produced in vitro by harvesting supernatants of spleen cell cultures from Swiss-Webster mice sensitized with Mycobacterium bovis strain BCG and challenged with old tuberculin. Treatment of C3H mouse spleen cell cultures with appropriate anti-Ia, anti-IgG, anti-Thy-1 or anti-Ly-2,3 sera resulted in a significant decrease in production of type II interferon. Removal of nylon wool adherent cells or cells with histamine receptors by column chromatography similarly caused reduced production of type II interferon. Recombination of spleen cell cultures treated with anti-Ia and anti-Thy-1 sera or of cells treated with anti-IgG and anti-Thy-1 resulted in restored production of type II interferon. Interferon production was also restored by combination of cells passed through histamine columns with anti-Ia treated cells, or those passed through nylon wool columns with anti-Thy-1 treated cells. Anti-Ly-1 serum treatment had no effect on interferon production. Removal of plastic-adherent cells or cells that had phagocytosed carbonyl iron also decreased interferon production, suggesting that macrophages were also involved in type II interferon production. Recombination of non-adherent spleen cells with anti-Ia and anti-Thy-1 sera treated spleen cells, however, did not restore interferon production, suggesting that other cells in addition to macrophages are depleted by the adherence procedure. These findings indicate that type II interferon is produced by suppressor or cytotoxic (Ly-2,3+) T lymphocytes in co-operation with one or two additional cell types: (i) B lymphocytes, and (ii) macrophages.
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PMID:In vitro production and cellular origin of murine type II interferon. 37 63

Eight intramuscular injections of 200 mg/kg of iron (DFe), given as iron dextran twice weekly in the week before and the three weeks after intravenous infection with about 10(7.5) colony-forming units of Mycobacterium avium, significantly prolonged (by about 11 days) the mean 'time-to-death' of immature male fowl (Gallus domesticus) compared with corresponding regimes using dextran (Dx) only or saline, When a proportion of the birds were examined 21 days after infection many of the abnormalities associated with the disease, including a marked hypochromic anaemia, were less severe in DFe-treated than in the Dx- or saline-treated chicks and there were about 10- to 85-fold fewer viable tubercle bacilli in the liver and spleen of the DFe-treated birds.
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PMID:Effect of repeated injections of iron dextran on the haematological, serological and pathological changes in experimental avian tuberculosis. 74 79

The effect of a nontoxic, water-soluble adjuvant (Neo-WSA) from delipidated cells of Mycobacterium smegmatis on the susceptibility of mice to infection with four challenge organisms was studied. An intravenous dose of 1 mg of Neo-WSA per mouse 24 hr before challenge enhanced resistance to infection with a fungus (Candida albicans), a gram-negative bacterium (Klebsiella pneumoniae), and a gram-positive bacterium (Streptococcus pneumoniae). Protection by Neo-WSA was not significant when the mice were challenged with a malarial parasite. Plasmodium berghei. When 1 mg of Neo-WSA was given intravenously to mice 10 min before challenge with C. albicans, protection was significant, but when the same dose was given two or six days prior to challenge, mice were not protected. The concentration of iron in serum had not changed significantly 1 or 24 hr after the intravenous injection of 1 mg of Neo-WSA. Thus Neo-WSA is capable of inducing nonspecific resistance to certain experimental infections in mice. The protection afforded by administration of Neo-WSA 10 min before challenge, the lack of protection afforded by administration of Neo-WSA six days before challenge, and the lack of significant change in the serum iron concentration clearly separate this compound from bacterial endotoxins, which are classical inducers of nonspecific resistance to infection.
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PMID:Nonspecific resistance to infection induced in mice by a water-soluble adjuvant derived from Mycobacterium smegmatis. 77 30

1. A superoxide dismutase [EC 1.15.1.1] was purified about 275-fold with a yield of 34% from Mycobacterium tuberculosis, strain H37Ra (attenuated strain), grown on a Sauton medium for two months. The purified enzyme was homogeneous as judged by polyacrylamide gel electrophoresis, and by analytical ultracentrifugation and sedimentation equilibrium studies. 2. The molecular weight of the enzyme was estimated to be approximately 88,000 by sedimentation equilibrium analysis. Since the molecular weight of the subunit was 21,000 as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, the enzyme appears to be composed of four subunits of equal size. 3. Electron spin resonance (ESR) spectra showed that the enzyme contained ferric iron, and metal analysis showed that the enzyme contained ferric iron, and metal analysis showed that approximately 3.7 atoms of iron were present per mole of the enzyme, indicating the occurrence of 1 atom of iron per subunit. 4. The amino acid composition was apparently similar to those of the iron-containing superoxide dismutases from Escherichia coli, luminous bacteria, Pseudomonas ovalis, and blue-green alga. 5. Antibodies against the enzyme were raised in rabbits and immunological studies were performed. The enzyme from M. tuberculosis, strain H37Rv (virulent strain), was found to have antigenic structures identical with those of the H37Ra enzyme. On the other hand, the manganese-containing superoxide dismutases from other species of mycobacteria, i.e., Mycobacterium species, strain Takeo, M. phlei and M. lepraemurium, showed only partial immunological identity with the H37Ra enzyme. 6. During the growth of M. tuberculosis, strain H37Ra, the enzyme was found to be secreted into the culture medium.
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PMID:Superoxide dismutase from Mycobacterium tuberculosis. 82 61


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