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 sandwich ELISA to detect specific protein antigens of Mycobacterium tuberculosis was developed by using polyclonal anti-BCG rabbit antibodies as the primary capture antibodies. The mycobacterial antigens were detected with horseradish peroxidase conjugated monoclonal antibodies (P 6) as secondary antibodies. The enzyme was detected by using 1,2 Phenylenediamine dihydrochloride (OPD) and Hydrogen peroxide as substrate. The antigen could be quantitated through linear regression analysis with lower detection limit of 1.25 micrograms/ml. 50 consecutive cases of infertility were examined by laparoscopy and tested for the presence of the antigen in the serum. Mycobacterial antigen could be detected in 9 of the 12 cases with definitive diagnosis of tuberculosis, 5 of the 23 where the diagnosis of tuberculosis was probable and in only 1 of 15 patients who had no laparoscopic abnormalities indicative of tuberculosis.
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PMID:Detection of antigens of Mycobacterium tuberculosis in patients of infertility by monoclonal antibody based sandwiched enzyme linked immunosorbent assay (ELISA). 836 16

Isoniazid-resistant isolates of Mycobacterium tuberculosis were transformed with a plasmid vector carrying the functional catalase-peroxidase (katG) gene. Expression of katG restored full drug susceptibility in isolates initially resistant to concentrations ranging from 3.2 to > 50 micrograms ml-1. Transformation with the corresponding katG gene from Escherichia coli resulted in low-level expression of catalase and peroxidase activities and conferred partial isoniazid sensitivity.
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PMID:Transformation with katG restores isoniazid-sensitivity in Mycobacterium tuberculosis isolates resistant to a range of drug concentrations. 839 39

We developed and evaluated a rapid test with monoclonal antibodies to identify cultures of Bordetella pertussis. Samples of 5 microliters of cells suspended in formalin-saline were dried onto a nitrocellulose disk. The disk was placed in a filtration device, and 5-microliters volumes of murine monoclonal antibody directed against B. pertussis lipooligosaccharide and peroxidase conjugate were added consecutively, with washing after each addition. The disk was removed and immersed in peroxidase substrate solution. All of 66 B. pertussis isolates confirmed by direct fluorescent-antibody assay were correctly identified by using four different monoclonal antibodies. One of the monoclonal antibodies did not react with over 20 bacterial species tested, including other Bordetella, Acinetobacter, Haemophilus, Moraxella, Mycobacterium, Neisseria, and Staphylococcus spp. This technique detected > or = 2 micrograms of lipooligosaccharide per ml or > or = 5 x 10(8) B. pertussis cells per ml. This rapid procedure used small amounts of reagents, needed less equipment, and was less subjective and more specific than the direct fluorescent-antibody assay.
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PMID:Rapid immunodot technique for identifying Bordetella pertussis. 841 27

The gene encoding catalase-peroxidase was cloned from chromosomal DNA of Rhodobacter capsulatus B10. The nucleotide sequence of a 3.7-kb SacI-HindIII fragment, containing the catalase-peroxidase gene (cpeA) and its flanking regions were determined. A 1728-bp open reading frame, coding for 576 amino acid residues (molecular mass 61516 Da) of the enzyme, was observed. A Shine-Dalgarno sequence was found 5 bp upstream from the translational start site. The deduced amino acid sequence coincides with that of the amino terminus and of four peptides derived from trypsin digestion of the purified catalase-peroxidase of R. capsulatus B10. The amino acid sequence of R. capsulatus catalase-peroxidase shows interesting similarities to the amino acid sequences of the hydroperoxidases of Escherichia coli (42.7%) and Salmonella typhimurium (39.9%), the peroxidase of Bacillus stearothermophilus (32.1%) and the catalase-peroxidase of Mycobacterium intracellulare (42.2%). As shown by a cpeA::lacZ fusion in trans in R. capsulatus, the expression of the catalase-peroxidase gene is regulated by oxygen. The promoter of the cpeA gene was localized within 320 bp upstream of the ATG start codon.
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PMID:Molecular cloning, sequence analysis and expression of the gene for catalase-peroxidase (cpeA) from the photosynthetic bacterium Rhodobacter capsulatus B10. 850 96

The intraphagosomal survival strategy of pathogenic mycobacteria was studied in bone marrow-derived mouse macrophages. These bacteria survive inside phagosomes by interfering in an unknown manner with phagosome processing which normally would lead to digestion of the phagocytic particle in phagolysosomes. Here, phagosome processing was compared for different phagocytic particles: live Mycobacterium avium, degradable Bacillus subtilis, or indigestible latex beads. We show detailed electron microscopic morphological observations which characterize various phases of interaction between endocytic organelles and phagosomes. We measured fusion of phagosomes with early endosomes or with lysosomes by using newly internalized endocytic contents (horseradish peroxidase, HRP) and membrane marker (plasma membrane glycoconjugates labeled with [3H]galactose via exoglycosylation). Morphometric analysis of these observations showed that the nature of the phagocytic particle affects phagosome processing: As long as particles remain undigested, maturation of phagosomes is prevented and they remain fusogenic towards early endosomes; concurrent to particle digestion, phagosome processing proceeds towards transfer of phagocytic contents to phagolysosomes which display kinetic and compositional characteristics of lysosomes. As an intact phagocytic particle, M. avium remains in non-matured phagosomes which fuse with early endosomes, but not with lysosomes. Fusion with early endosomes is reduced, thereby indicating the stage where this endoparasite exerts its effect.
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PMID:Phagocytic processing of the macrophage endoparasite, Mycobacterium avium, in comparison to phagosomes which contain Bacillus subtilis or latex beads. 857 63

The systems participating in detoxification of reactive oxygen intermediates in Mycobacterium tuberculosis are believed to play a dual role in the biology of this highly adapted human pathogen: (i) they may contribute to the survival of this bacterium in the host; and (ii) alterations in the gene encoding catalase/peroxidase have been linked to this organism's resistance to the front-line antituberculosis drug isoniazid. These relationships prompted us to extend investigations of the oxidative-stress-response systems in M. tuberculosis by analysing the alkyl hydroperoxide reductase gene ahpC and its putative regulator oxyR. Surprisingly, the oxyR gene was found to be inactivated by multiple lesions in M. tuberculosis H37Rv. These alterations were observed in all M. tuberculosis strains tested, and in members of the M. tuberculosis complex: Mycobacterium bovis BCG, Mycobacterium africanum, and Mycobacterium microti. The corresponding region carrying these genes in Mycobacterium leprae, an organism not sensitive to isoniazid, has a complete oxyR gene divergently transcribed from ahpC. An increase in minimal inhibitory concentration for isoniazid was observed upon transformation of M. tuberculosis H37Rv with cosmids carrying the oxyR-ahpC region of M. leprae. In keeping with the observed inactivation of oxyR, transcriptional activity of the corresponding region in M. tuberculosis was an order of magnitude lower than that of the oxyR gene from M. leprae. While the loss of this putative regulator of oxidative-stress response in M. tuberculosis is paradoxical considering the fact that survival in host macrophages is regarded as a critical feature of this pathogen, it offers a partial explanation for the exquisite sensitivity of M. tuberculosis to isoniazid.
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PMID:Mycobacterium tuberculosis is a natural mutant with an inactivated oxidative-stress regulatory gene: implications for sensitivity to isoniazid. 859 38

A Bacillus Calmette Guerlin (BCG) DNA fragment was identified which conferred hypersensitivity to isoniazid (INH) upon Mycobacterium smegmatis (Ms) when present on a multicopy plasmid. The gene cluster present on this fragment contains the genes encoding ribosomal proteins L36 (rpmJ), S13 (rpsM), S11 (rpsK) and S4 (rpsD), as well as the gene encoding initiation factor-1 (infA), an open reading frame of unknown function (ORFX) and a putative promoter region. The rpsM gene, from either BCG or Ms is necessary and sufficient to produce the INH-hypersensitive phenotype in Ms, but the gene cluster has no effect on INH sensitivity when introduced into BCG on a multicopy plasmid. The presence of rpsM on a multicopy plasmid also causes an increase in catalase/peroxidase (Kat/Prx) activity in Ms. The overproduction of S13 may induce a stress response, resulting in increased expression of katG (encoding Kat/Prx) in Ms, thereby causing hypersensitivity to INH.
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PMID:Overproduction of mycobacterial ribosomal protein S13 induces catalase/peroxidase activity and hypersensitivity to isoniazid in Mycobacterium smegmatis. 862 Oct 83

Immunohistochemical studies were performed to determine the presence and distribution of polypeptide transforming growth factor (TGF)-beta 1, a cytokine with macrophage-suppressing activity, in skin biopsies from 41 patients with different clinical forms of leprosy. We used an anti-TGF-beta 1 polyclonal antibody and the avidinbiotin-peroxidase (ABC complex) method. The results demonstrated that the lesions of the lepromatous and borderline lepromatous forms presented intense cytoplasm staining for TGF-beta 1 in the cells of the dermal infiltrate. A reaction of moderate intensity was observed in the cells of granulomas from borderline borderline cases, whereas no detectable immunoreaction was observed in granuloma cells from the tuberculoid and borderline tuberculoid forms. Considering that in the lepromatous leprosy form Mycobacterium leprae multiplies in the cytoplasm of macrophages and the lesions are diffuse and consist of poorly differentiated young macrophages, we believe that these alternations may be explained at least in part by the presence of TGF-beta 1 in the dermal infiltrate. Production of the cytokine may be induced by the presence of the bacillus itself and of its constituents, causing a mechanism of parasite evasion. Similarly, the absence of TGF-beta 1 in tuberculoid leprosy, which progresses with a specific immune response to M. leprae, may explain the intense differentiation of macrophage cells with the formation of well defined epithelioid granulomas capable of eliminating most of the bacilli.
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PMID:Detection of transforming growth factor-beta 1 in dermal lesions of different clinical forms of leprosy. 877 45

The mycobacterial ideR protein is a homologue of the diphtheria-toxin repressor DtxR. We have previously demonstrated that Mycobacterium tuberculosis ideR, like DtxR, represses transcription of Corynebacterium diphtheriae iron-regulated promoters in vivo and binds to C. diphtheriae operators in a metal-dependent manner in vitro. We show here that ideR mutants of M. smegmatis, constructed by allelic replacement, were defective in their ability to repress siderophore biosynthesis in the presence of iron. They were also more sensitive to hydrogen peroxide and had decreased levels of catalase/peroxidase (KatG) and manganese superoxide dismutase (Mn-SOD). This indicates that ideR is a negative regulator of siderophore production and is required for the response to superoxide- and hydrogen peroxide stress. We propose that ideR is the mycobacterial counterpart of the Escherichia coli Fur protein, i.e. It is a pleiotropic regulator that couples iron metabolism to the oxidative-stress response.
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PMID:An ideR mutant of Mycobacterium smegmatis has derepressed siderophore production and an altered oxidative-stress response. 893 36

Recent studies examining the molecular mechanisms of isoniazid (INH) resistance in Mycobacterium tuberculosis have demonstrated that a significant percentage of drug-resistant strains are mutated in the katG gene which encodes a catalase-peroxidase, and the majority of these alterations are missense mutations which result in the substitution of a single amino acid. In previous reports, residues which may be critical for enzymatic activity and the drug-resistant phenotype have been identified by evaluating INH-resistant clinical isolates and in vitro mutants. In this study, site-directed mutagenesis techniques were utilized to alter the wild-type katG gene from M. tuberculosis at 13 of these codons. The effects of these mutations were determined using complementation assays in katG-defective, INH-resistant strains of Mycobacterium smegmatis and Mycobacterium bovis BCG. This mutational analysis revealed that point mutations in the katG gene at nine of the 13 codons can cause drug resistance, and that enzymatic activity and resistance to INH are inversely related. In addition, mutations in the mycobacterial catalase-peroxidase which reduce catalase activity also decrease peroxidase activity.
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PMID:Site-directed mutagenesis of the katG gene of Mycobacterium tuberculosis: effects on catalase-peroxidase activities and isoniazid resistance. 893 40


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