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)

Cell-envelope fractions were isolated from the rapidly growing saprophyte Mycobacterium smegmatis following growth in glycerol/asparagine medium under both iron-limited (0.02 microgram Fe ml-1) and iron-sufficient (2.0 to 4.0 micrograms Fe ml-1) conditions. Examination of these preparations by SDS-PAGE demonstrated the production of at least four additional proteins when iron was limiting. These iron-regulated envelope proteins (IREPs) were ascribed apparent molecular masses of 180 kDa (protein I), 84 kDa (protein II), 29 kDa (protein III) and 25 kDa (protein IV). All four proteins were present in both cell-wall and membrane preparations but spheroplast preparations were devoid of the 29 kDa protein. Attempts at labelling the proteins with 55FeCl3 or 55Fe-exochelin, the siderophore for iron uptake, were unsuccessful, though this was attributed to the denatured state of the proteins following electrophoresis. Antibodies were raised to each of the four proteins: the one raised to protein III inhibited exochelin-mediated iron uptake into iron-deficiently grown cells by 70% but was ineffective against iron uptake into iron-sufficiently grown cells. As exochelin is taken up into both types of cells by a similar process, protein III may not be a simple receptor for iron uptake though the results imply some function connected with this process. The role of the other IREPs is less certain.
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PMID:Iron transport in Mycobacterium smegmatis: occurrence of iron-regulated envelope proteins as potential receptors for iron uptake. 312 39

Following iron-deficient growth, mycobactins and exochelins were isolated from 11 strains of Mycobacterium tuberculosis (including type strains of the virulent H37Rv and avirulent H37Ra organisms) as well as from M. bovis (one strain), M. bovis BCG (two strains), M. africanum (eight strains) and M. xenopi (one strain) but not from M. microti (one strain). The mycobactins from the tuberculosis group (M. tuberculosis, M. bovis and M. africanum) were identical and could each be resolved into four compounds by thin-layer chromatography (TLC) and into several fractions by high-performance liquid chromatography, supporting previous claims that this group is a single taxon. Exochelins were all chloroform-soluble and showed no species specificity; no single exochelin was recognized by TLC that had not been previously seen in M. avium or a related species.
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PMID:Mycobactins and exochelins of Mycobacterium tuberculosis, M. bovis, M. africanum and other related species. 314 75

Immunohistochemical examination of iron-binding proteins was carried out in the formalin-fixed mesenteric lymph nodes of normal cattle and of cattle with paratuberculosis. Ferritin (FT) and lactoferrin (LF) were found in the granulomas in ileal lymph nodes from six infected cattle. A weak reaction for transferrin (TF) was found in granulomas of a lymph node from one of the infected cattle. FT was found in the macrophages in the medullary sinuses of normal and infected nodes; however, the reaction in infected nodes was generally stronger than that in normal ones. LF in the macrophages was found in only two infected nodes. Neutrophils in both normal and infected cattle always reacted strongly for LF. The TF was always found in the blood vessels and intracellular space. These results suggest that: (1) FT and LF may be important in vivo sources of iron for Mycobacterium paratuberculosis, since their own iron-binding compounds are considered to acquire iron from FT and LF in vitro; (2) the increase in FT and LF in the granulomas may be related to inflammatory hyposideraemia associated with paratuberculosis and (3) epithelioid and giant cells may have a different iron metabolism, from normal macrophages.
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PMID:The distribution of ferritin, lactoferrin and transferrin in granulomatous lymphadenitis of bovine paratuberculosis. 318 87

Exochelins, water-soluble siderophores of mycobacteria, were isolated and partially purified from culture filtrates of iron-deficiently grown cultures of Mycobacterium neoaurum NCTC 10439 and an armadillo-derived Mycobacterium (ADM 8563). Two biologically active fractions mediating iron uptake were isolated from each bacterium which not only were able to transport iron into the producing organism but also into suspensions of Mycobacterium leprae isolated from armadillo liver. The rate of exochelin-mediated iron uptake into M. leprae was about 1.5% of the rate observed into the producing organisms. The process of iron uptake appears to be by facilitated diffusion as it was not inhibited by HgCl2, NaN3, KCN, dinitrophenol or carbonyl cyanide m-chlorophenylhydrazone. Since no uptake of iron occurred into iron-sufficient ADM cells, this may indicate that M. leprae, as recovered from an animal tissue, had been growing iron-deficiently in order for iron uptake to have been demonstrated in vitro.
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PMID:Exochelin-mediated iron acquisition by the leprosy bacillus, Mycobacterium leprae. 330 44

In two patients with the acquired immunodeficiency syndrome (AIDS), multiple erythematous cutaneous lesions developed, revealing acid-fast organisms on Fite's stain. Initial culture results on the first patient were negative; however, repeat cultures on hemin-enriched media were positive for Mycobacterium haemophilum. Despite antimycobacterial therapy, lesions persisted until the patients' death. M. haemophilum should be a diagnostic consideration when smears of peripheral (especially skin) lesions from AIDS patients show acid-fast organisms. Cultures in such patients should be done with iron hemin- or ferric ammonium citrate-enriched media.
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PMID:Disseminated Mycobacterium haemophilum infection in two patients with the acquired immunodeficiency syndrome. 334 74

Two groups of C57 and C3H mice of 5 weeks of age were infected via the intraperitoneal route with 2.0 mg (wet weight) of Mycobacterium paratuberculosis. These were maintained with a similar number of segregated and non-inoculated mice of the same strains under specially controlled conditions of low, medium and high iron intake. Mice were killed and bled at 7 months post-infection and assessments of haematological parameters and the degree of mycobacterial granulomatous involvement of abdominal and other tissues were made. In addition, the total mycobacterial numbers visible in macrophages in standardized histological sections of liver, spleen and bone marrow in the presence or absence of stainable iron storage compounds were assessed using a double staining technique for iron and mycobacteria. Moderate to marked anaemia in both C57 and C3H mice on low iron intake, irrespective of infection, indicated that an effective low iron status was achieved in the animals by dietary manipulation. Medium and high iron intake groups exhibited normal haematological parameters. Iron storage compounds were readily visible in liver microgranulomas of mice on medium and high, but not on low iron intake. In liver, spleen and bone marrow samples, mycobacterial counts in iron-containing microgranulomas were significantly higher than in those without stainable iron. Increased frequencies of residual and progressive infection were associated with increased iron intake. The greater susceptibility of the C57 strain was evident from the significantly higher liver microgranuloma counts, higher mycobacterial numbers and greater progressive infection when compared with the C3H strain. These findings in mice strongly suggest that slow multiplication of M. paratuberculosis is enhanced in iron-replete compared with iron-deficient macrophages. This enhancement occurs despite the capacity of the less susceptible strain of mouse to limit the spread of the organism within the body.
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PMID:The effect of different levels of iron intake on the multiplication of Mycobacterium paratuberculosis in C57 and C3H mice. 338 91

Abnormal phagocytosis of Mycobacterium leprae by macrophages of lepromatous patients was demonstrated under various conditions. The largest proportion of macrophages with an excessive bacterial load belonged to the lepromatous group of patients. Lepromatous macrophages treated with Cytochalasin B, an inhibitor of phagocytosis, exhibited a significantly lower degree of ingestion of heat-killed organisms whereas uptake of 'viable' organisms was not affected to the same extent. Regulation of phagocytosis was studied by noting the rate of phagocytosis of M. leprae after the ingestion of a primary particle viz carbonyl iron. Solely in lepromatous macrophages, phagocytosis of carbonyl iron did not result in a decreased uptake of M. leprae implying aberrant phagocytic activity. Lastly, excessive phagocytosis was always noted in macrophages of familial contacts of leprosy patients who displayed decreased Fc receptor expression after M. leprae ingestion. This is of interest since phagocytosis, like Fc receptor expression, is a membrane dependent event and other membrane associated defects have been recognized by us earlier in lepromatous macrophages.
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PMID:M. leprae phagocytosis and its association with membrane changes in macrophages from leprosy patients. 351 65

Twenty-eight specimens obtained either from organ bundles in the body cavities of intact mummies, from damaged mummies, or from isolated canopic jars were examined for tissue identification and histopathologic study. The methods of rehydration and fixation were optimized by application to 40 dehydrated modern samples before studies of mummified tissue were undertaken. The tissue of origin could be definitely identified in 24 of the 28 specimens. Even small fragments obtained from isolated canopic jars proved suitable for histologic study. Six lung specimens were selected for more detailed study. All six showed focal deposition of anthracotic pigment. Electron diffraction and electron microprobe analysis of one of the small, polarizable crystals associated with the anthracosis indicated a mineral content of silica, aluminum, and iron. Two specimens showed focal areas of calcification consistent with old mycobacterial disease. Other histopathologic findings included evidence of pulmonary edema, emphysema, and pneumonia.
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PMID:Tissue identification and histologic study of six lung specimens from Egyptian mummies. 354 13

Granulomatous lesions of bovine paratuberculosis contained ferritin, lactoferrin, and a small amount of transferrin, as demonstrated by the immunohistochemical method. Macrophages in the normal bovine ileum did not contain lactoferrin and transferrin; however, ferritin was found in individual macrophages of Peyer's patches. These results may help elucidate the relationship between intracellular growth of Mycobacterium paratuberculosis and the presence of iron-binding proteins in the granulomas.
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PMID:Immunohistochemical distribution of ferritin, lactoferrin, and transferrin in granulomas of bovine paratuberculosis. 369 98

Succinate dehydrogenase (SDH) was solubilized from membranes of Mycobacterium phlei by Triton X-100 with a recovery of about 90%. The solubilized SDH was purified about 90-fold by Sephacryl S-300, DEAE-cellulose, hydroxylapatite, and isoelectric focusing in the presence of Triton X-100 with a 20% recovery. SDH was homogeneous, as determined by polyacrylamide gel electrophoresis in nondenaturing gels containing Triton X-100. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the enzyme revealed two subunits with molecular weights of 62,000 and 26,000. SDH is a flavoprotein containing 1 mol of flavin adenine dinucleotide, 7 to 8 mol of nonheme iron, and 7 to 8 mol of acid-labile sulfide per mol of protein. Using phenazine methosulfate and 2,6-dichloroindophenol as electron acceptors, the enzyme had an apparent Km of 0.12 mM succinate. SDH exhibited a sigmoidal relationship of rate to succinate concentration, indicating cooperativity. The enzyme was competitively inhibited by fumarate with a Ki of 0.15 mM. In the absence of Triton X-100, the enzyme aggregated, retained 50% of the activity, and could be resolubilized with Triton X-100 with full restoration of activity. Cardiolipin had no effect on the enzyme activity in the absence of Triton X-100, but it stimulated the activity by about 30% in the presence of 0.1% Triton X-100 in the assay mixture. Menaquinone-9(2H), isolated from M. phlei, had no effect on the enzyme activity either in the presence or absence of Triton X-100.
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PMID:Solubilization, purification, and characterization of succinate dehydrogenase from membranes of Mycobacterium phlei. 372 23


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