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)

T-cell populations from guinea-pigs sensitized to the protein antigens purified protein derivative of Mycobacterium tuberculosis, ovalbumin, or horseradish perioxidase can be selectively depleted of cells capable of initiating antigen-specific macrophage-lymphocyte clusters in vitro. The depletion is achieved by incubating the T cells on a monolayer of antigen-pulsed macrophages in a Petri dish for some hours and then gently aspirating the cells not adhering to the bottom of the dish. When subsequently assayed, the aspirated cells were found to be depleted of cluster-initiating lymphocytes committed to horseradish peroxidase, monolayers of macrophages pulsed with that antigen must be used. The optimum time for incubation on the absorbing monolayer appears to be 4 h, and two successive incubations are more effective than one. The cell density of the absorbing monolayer and the handling of the Petri dish may be critical for effective removal of the cluster-initating lymphocytes. With optimum procedure we have achieved up to 90% depletion of specific cells with no depletion of cells committed to a control antigen.
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PMID:Macrophage-lymphocyte clusters in the immune response to soluble protein antigen in vitro. IX. Antigen-pulsed macrophages as a tool for specific absorption of cluster-initiating T cells. 9 61

At sub-bactericidal concentrations of hydrogen peroxide, Mycobacterium tuberculosis was killed by hydrogen peroxide/peroxidase/halide microbicidal systems. The halide cofactor could be either iodide or, with much lower efficiency, chloride. Omission of any one of the reactants eliminated the tuberculocidal effect. Differences in susceptibility between different strains of M. tuberculosis did not correlate with virulence differences. The observations are discussed in the context of host defence mechanisms against tuberculosis.
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PMID:Virulence of Mycobacterium tuberculosis and susceptibility to peroxidative killing systems. 9 84

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

Lepromatous tissue from armadillos inoculated 24--36 months earlier with Mycobacterium leprae was obtained for electron microscopic studies. Cytochemically stained lepromas revealed a subpopulation of macrophages containing peroxisomes. These peroxidase reactive macrophages were not infected with bacilli. Acid phosphatase was present in macrophages and many of these were infected with bacilli and contained vacuoles and lipid globules. Within the membrane-bound vacuoles, acid phosphatase surrounded bacilli. However, the reaction product ended abruptly at a 15--40 millimicron thick zone of low electron density surrounding intact bacilli. Acid phosphatase was more intensely reactive and localized less precisely in heavily infected and vacuolated macrophages than in lightly and non-infected cells. The effectiveness of this bacillary barrier and the numerous infected macrophages with substantial acid phosphatase argue against the ability of acid phosphatase to protect host cells from leprosy bacilli. Evidence suggests a protective action of peroxidase or the rapid turnover of macrophages within lepromas. Granular and membranous debris were commonly seen within vacuoles of infected macrophages. A portion of the debris was ultrastructurally similar to bacillary matrix and was nonreactive for peroxidase and acid phosphatase. Following homogenization and centrifugation, similar materials banded with bacilli above 60% sucrose. Another portion of the debris was ultrastructurally similar to host lysosomal matrix and was reactive for acid phosphatase. Results support the concept of dual host and parasitic origins of the debris found in phagolysosomes of infected macrophages. Transparent, oval Epon defects remained eccentric to the majority of intact bacilli in centrifuged fractions. Apparently, an intrinsic property of leprosy produced these Epon defects.
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PMID:Electron microscopy of peroxidase and acid phosphatase in leprous and uninfected armadillo macrophages: a macrophage subpopulation contains peroxisomes and lacks bacilli. 36 52

The isolation of an acid-fast microorganism of the genus Mycobacterium is reported. Its most relevant characteristics are the intense red color and the initial spheric shape of colonies which furtherly evolve to a peculiar division. The biochemical products from test bacteria as niacin, nitrase, lipase, phosphatase, TCH, catalase, peroxidase and a series of 11 amides as well as the tests for susceptibility against antibacillary drugs and biological tests are described. The patterns obtained permit the characterization of this species as one non previously described. The name Mycobacterium cubense, n. sp. is suggested.
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PMID:[Mycobacterium cubense. A new pigmented species of slow growth]. 39 86

Mycobacterium phlei contains two catalase activities and a single peroxidase activity. The latter is associated with one of the catalases. The single catalase-peroxidase enzyme accounted for 75% of the total catalase activity and was lost upon acquisition of resistance to the antitubercular drug isoniazid (INH). Heat-treated (68 degrees C) wild-type cells showed similar decreases in catalase activity as well as complete loss of peroxidase activity. Catalase activity in the INH-resistant strain of M. phlei (Inh(r)) was unaffected by heating. The heat-sensitive catalase of the wild-type M. phlei was completely inhibited by 0.1 M INH, and Cu(2+) enhanced this inhibitory effect by 100-fold. No inhibition of activity was found with the heat-stable enzyme. Equivalent inhibition of catalase was also observed with nicotinic acid hydrazide and benzoic acid hydrazide. Peroxidase activity was also completely inhibited by any one of the three hydrazides, either INH, benzoic acid hydrazide, or nicotinic acid hydrazide at 10(-3) M. The presence of two catalase activities and the loss of one (catalase-peroxidase) on acquiring INH resistance or heating wild-type cells was confirmed by acrylamide gel electrophoresis of the cell-free extracts.
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PMID:Differentiation of catalases in Mycobacterium phlei on the basis of susceptibility to isoniazid: association with peroxidase and acquired resistance to isoniazid. 92 Dec 49

Mycobacterium carotenum is more tolerant to the action of hydrogen peroxide than its white, carotenoidless mutant. This elevated tolerance to H2O2 correlates with a higher content of DNA, RNA, and polysaccharides in the cells; it is not related to the content of proteins and lipids, or to the level of the catalase and peroxidase activity.
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PMID:[Tolerance to H202 of Mycobacterium carotenum and its carotinoidless mutant]. 122 42

The activation of catalase genes in response to oxidative stress may contribute to the intracellular survival of mycobacteria. In this report, the nucleotide sequence of a mycobacterial catalase gene is described. The deduced protein sequence of this Mycobacterium intracellulare gene (MI85) was 60% identical to the Escherichia coli hydroperoxidase I (HPI) protein, 59% identical to the Salmonella typhimurium (HPI) catalase, and 47% identical to a Bacillus stearothermophilus peroxidase. The MI85 protein, expressed in E. coli, has also been shown to have peroxidase and catalase activities. Furthermore, Southern blot hybridizations, which demonstrated that a MI85 gene probe hybridizes with chromosomal DNA from thirteen different strains of mycobacteria, suggest that this catalase-peroxidase gene is prevalent in the mycobacterial genus. The availability of catalase gene probes should permit an evaluation, at the molecular level, of the role of catalase in mycobacterial pathogenesis.
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PMID:The catalase-peroxidase of Mycobacterium intracellulare: nucleotide sequence analysis and expression in Escherichia coli. 133 34

A naturally occurring outbreak of Mycobacterium bovis infection in captive wild elk (wapiti) in Montana was confirmed by mycobacteriologic examination. Twenty-eight of 143 elk responded to M. bovis purified protein derivative (PPD) tuberculin injected intradermally in the cervical region (SCT). The results of comparative cervical tuberculin skin tests conducted within 9 days of SCT revealed greater responses to M. bovis PPD tuberculin than to M. avium PPD tuberculin in 23 of 28 elk responding. At necropsy, several grossly visible tuberculous lesions were observed in the parenchyma of the lung, thoracic lymph nodes, and submandibular lymph nodes. Microscopic examination of appropriately stained tissue sections revealed the presence of granulomatous lesions containing acid-fast bacilli. An enzyme-linked immunosorbent assay (ELISA) was developed using a sarkosyl extract of M. bovis (antigen) and peroxidase-labeled protein G (conjugate); reactions were detected in the sera of 8 of 9 elk responding to M. bovis PPD tuberculin. Lymphocyte blastogenic assay responses were detected using M. bovis antigens in 7 of 9 elk positive on skin tests using M. bovis PPD.
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PMID:Mycobacterium bovis infection in North American elk (Cervus elaphus). 145 45

INH-resistant mutants of Mycobacterium aurum and M. smegmatis were isolated and characterized in an attempt to provide fresh insight into the activity of isoniazid (INH), a key antibiotic in the treatment of tuberculosis. In both cases, high levels of resistance were accompanied by slower growth rate, by loss of peroxidase and reduced catalase activities, although mycolic acid production was unaffected. A gene homologous to the katG gene of M. tuberculosis, encoding peroxidase-catalase, was detected in wild-type and INH-resistant strains and it appears that INH resistance may stem from the loss of its product.
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PMID:Isolation and characterization of isoniazid-resistant mutants of Mycobacterium smegmatis and M. aurum. 148 56


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