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)

Cosmid B577, a member of the collection of ordered clones corresponding to the genome of Mycobacterium leprae, contains a gene, provisionally called pon1, that encodes an 821-amino-acid-residue high-molecular-mass class A penicillin-binding protein, provisionally called PBP1. With similar amino acid sequences and modular designs, M. leprae PBP1 is related to Escherichia coli PBP1a and PBP1b, bienzymatic proteins with transglycosylase and transpeptidase activities. When produced in E. coli, His tag-labelled derivatives of M. leprae PBP1 adopt the correct membrane topology, with the bulk of the polypeptide chain on the surface of the plasma membrane. They defy attempts at solubilization with all the detergents tested except cetyltrimethylammonium bromide. The solubilized PBP1 derivatives can be purified by affinity chromatography on Ni2+-nitrilotriacetic acid agarose. They have low affinities for the usual penicillins and cephalosporins.
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PMID:Identification and overexpression in Escherichia coli of a Mycobacterium leprae gene, pon1, encoding a high-molecular-mass class A penicillin-binding protein, PBP1. 862

A wild type strain of Mycobacterium smegmatis mc2 155 was serially adapted to 64 fold of minimal inhibitory concentration of an antimycobacterial agent, ciprofloxacin. This clone (CIPr) exhibited cross resistance to ofloxacin and ethidium bromide. The rate of drug efflux was accelerated in CIPr compared to the wild type strain. Verapamil, a calcium channel blocker, enhanced the drug accumulation in CIPr by diminishing the efflux and thus reversed the resistant phenotype. Additionally, a missense mutation was detected in the quinolone resistance determining region of the DNA-gyrase A subunit of CIPr. Taken together, these results suggest that drug efflux plays a major role in conferring such a high level of resistance in CIPr, in addition to the mutation in the DNA-gyrase locus.
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PMID:Involvement of an efflux system in mediating high level of fluoroquinolone resistance in Mycobacterium smegmatis. 880 41

A known intermediate, (3 R, S; 5 R,S)-3,5-dimethyl-6-triphenylmethyloxyhexanal gave, in a Wittig reaction with 1-octyltriphenylphosphonium bromide and n-butyl lithium in anhydrous tetrahydrofuran, a mixture of olefininic compounds. Trityl deprotection and hydrogenation of the double bond afforded the (2 R, S; 4 R,S)-2,4-dimethyltetradecanols. Oxidation of the alcohol functionality using pyridinium dichromate in anhydrous N,N'-dimethylformamide gave racemic, (2 R, S; 4 R,S)-2,4-dimethyltetradecanoic acids, which were converted to their methyl esters. 2,4-Dimethyltetradecanoic acids are constituents of glycolipid antigens from Mycobacterium kansasii.
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PMID:Synthesis of racemic 2,4-dimethyltetradecanoic acid from Mycobacterium kansasii. 882 70

One hundred fifty-three blood samples from patients positive for the human immunodeficiency virus (HIV) were analyzed by polymerase chain reaction (PCR) to detect the presence of Mycobacterium avium. Samples were collected from patients who also had blood cultures performed by a radiometric method. Blood samples were centrifuged on a Ficoll-Hypaque gradient to purify peripheral blood mononuclear cells. The purified cells were washed and incubated with a resin, boiled to release mycobacterial DNA, and then amplified. Polymerase chain reaction products were detected by a nonisotopic method. A 123 base-pair (bp) insertion sequence, namely IS6110, from Mycobacterium tuberculosis complex was also included in the reaction as an internal control of Taq polymerase activity to exclude the presence of enzyme inhibitors. This IS6110 fragment can be distinguished from the 383 bp target product on ethidium bromide-stained agarose gel and may also be used in a colorimetric assay. Such results were compared with the results of culture and indicated that the assay is as sensitive as bacteriological methods, though faster.
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PMID:Detection and identification of Mycobacterium avium in the blood of AIDS patients by the polymerase chain reaction. 887 71

The activities of free and liposomal resorcinomycin A against Mycobacterium avium-Mycobacterium intracellulare complex (MAC) grown in broth and in murine peritoneal macrophages were evaluated. Liposomal resorcinomycin A was composed of dimyristoyl phosphatidylcholine and phosphatidylinositol at a molar ratio of 9:1. Both free resorcinomycin A and liposomal resorcinomycin A showed no toxicity to macrophages at concentrations up to 50 micrograms/ml, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Minimal inhibitory concentrations of free resorcinomycin A and liposomal resorcinomycin A in broth were 6 and 12 micrograms/ml, respectively, as determined by the MTT colorimetric microassay. In macrophages, liposomal resorcinomycin A caused significantly higher intramacrophage antimycobacterial activity than the free form of the drug. At doses ranging from 6 to 50 micrograms/ml, liposomal resorcinomycin A caused 50 to 93% MAC growth inhibition, respectively (as determined by CFU), while free resorcinomycin A was associated with 33 to 62% MAC growth inhibition, respectively, 3 days after drug treatment. In addition, antimycobacterial activity of liposomal resorcinomycin A in macrophages was maintained 7 days after treatment, whereas the activity of free resorcinomycin A was reduced to negligible 3 days after treatment. In summary, liposome encapsulation of resorcinomycin A resulted in significant enhancement of antibacterial activity against intramacrophagic MAC infection.
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PMID:Enhanced intramacrophage activity of resorcinomycin A against Mycobacterium avium-Mycobacterium intracellulare complex after liposome encapsulation. 891 61

Specific microbial reactions were used for the preparation of metabolites of 3-ketodesogestrel (13-ethyl-17 beta-hydroxy-11-methylene-18,19-dinor-17 alpha-pregn-4-en-20-yn-3-one, the active from of the progestagen desogestrel. Clostridium paraputrificum transformed 3-ketodesogestrel (KDG) to the 5 beta-dihydro and tetrahydro metabolites 13-ethyl-17 beta-hydroxy-11-methylene-18,19-dinor-5 beta, 17 alpha-pregnan-20-yn-3-one and 13-ethyl-11-methylene-18,19-dinor-5 beta, 17 alpha-pregnan-20-yne-3 alpha, 17 beta-diol, respectively. The epimeric compound 13-ethyl-11-methylene-18,19-dinor-5 beta, 17 alpha-pregnan-20-yne-3 beta, 17 beta-diol was obtained by chemical reduction of the 3-oxo compound. Mycobacterium smegmatis converted KDG to metabolites of the 5 alpha H-series: 13-ethyl-17 beta-hydroxy-11-methylene-18,19-dinor-5 alpha, 17 alpha-pregnan-20-yn-3-one, 13-ethyl-11-methylene-18,19-dinor-5 alpha, 17 alpha-pregnan-20-yne-3 alpha, 17 beta-diol and 13-ethyl-11-methylene-18,19-dinor-5 alpha, 17 alpha-pregnan-20-yne-3 beta, 17 beta-diol. The ring A-aromatized analog of KDG 13-ethyl-11-methylene-18,19-dinor-17 alpha-pregna-1,3,5(10)-trien-20-yne-3,17 beta-diol was obtained by microbial 1-dehydrogenation with Rhodococcus rhodochrous. Additionally, chemical syntheses of the microbially obtained KDG metabolites listed above were carried out. These included Birch reduction, reduction of KDG with sodium borohydride in aqueous pyridine and in methanol, reduction of KDG with potassium selectride in tetrahydrofuran, and dehydrogenation of KDG with cupric-II bromide in acetonitrile. The problems encountered in chemical syntheses favor the microbial procedures. The compounds were characterized by mass spectra (MS), IR, and circular dichroism (CD). Complete assignments of 1H and 13C chemical shifts were made using homo- and heteronuclear 2-DN-NMR spectroscopy. Chromatographic [gas-liquid chromatography (GLC), high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC)] data of all the prepared KDG metabolites are presented.
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PMID:Preparation of 3-ketodesogestrel metabolites by microbial transformation and chemical synthesis. 917 31

Several members of the Actinomycetales, including the medically important mycobacteria, produce 1-D-myo-inosityl-2-(N-acetyl-L-cysteinyl)amino-2-deoxy-alpha-D- glucop yranoside (trivial name mycothiol) as their principal low-molecular-mass thiol. The pseudo-disaccharide component of mycothiol, 1-D-myo-inosityl-2-amino-2-deoxy-alpha-D-glucopyranoside (alpha-D-GI), was synthesized by ligation of 1-D,L-2,3,4,5, 6-penta-O-acetyl-myo-inositol to 3,4,6-tri-O-acetyl-2-deoxy- 2-(2,4-dinitrophenylamino)-alpha-D-glu- copyranosyl bromide to give, in the first instance, an isomeric mixture of alpha- and beta-linked pseudo-disaccharides. The alpha-coupled D,D and D,L isomers, alpha-D-GI and alpha-L-GI respectively, were purified from the mixture by TLC, followed by removal of the protecting groups. A cell-free extract of Mycobacterium smegmatis catalysed the ligation of cysteine, acetate and alpha-D-GI in the presence of ATP and Mg2+ to form mycothiol, as judged by HPLC. When no acetate was added to the incubation mixture, an additional thiol accumulated. In the presence of [14C]acetate no radiolabel was recovered in this species, but only in mycothiol. The additional thiol was isolated as the bimane derivative, and 1H and 1H-1H COSY NMR spectra confirmed its identity as desacetylmycothiol. A more complete conversion of desacetylmycothiol into mycothiol was achieved in the presence of acetyl-S-CoA. These results indicate that the biosynthesis of mycothiol proceeds by the sequential addition of cysteine and acetate to alpha-D-GI. The inositol moiety appears to be an important determinant of specificity, since alpha-L-GI was poorly utilized.
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PMID:Biosynthesis of mycothiol: elucidation of the sequence of steps in Mycobacterium smegmatis. 927 Oct 81

The 18 kDa antigenic protein from Mycobacterium leprae (P) or its N-acyl derivative (AP) was incorporated in dioctadecyldimethylammonium bromide (DODAB) liposomes in water or in phosphate-buffered saline (PBS). In water, 100% P incorporation in liposomes contrasts with 65% in PBS. There is 75-80% AP incorporation to liposomes in water against 55-65% in PBS, showing that attachment of hydrophobic residues to the protein, instead of increasing, further decreases incorporation to the liposomes. From protein adsorption on latex, P affinity is larger than AP affinity for the latex surface whereas limiting adsorption for AP is much larger than that obtained for P, possibly due to AP aggregation in solution. P-induced rupture of liposomes containing [14C]sucrose was evaluated from dialysis of protein/liposomes mixtures. In water, P incorporation to the liposomes causes leakage of radioactive contents contrasting with the absence of leakage for P incorporation in PBS. Immunization tests for delayed type hypersensitivity indicate a enhancement of cell-mediated immunological response towards P/DODAB complexes that is not obtained for the isolated protein. Absence of leakage for P in PBS is associated with a P "lying-over" on the liposome and optimization of protein presentation to the immunological system.
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PMID:Interactions between cationic liposomes and an antigenic protein: the physical chemistry of the immunoadjuvant action. 937 23

This population genetics study was done to determine the degree of genetic diversity amongst clinical isolates of Mycobacterium tuberculosis in one of the largest provinces of South Africa. Three hundred and fifty-nine individual cultures were obtained from single patients over a nine-month period. Bacterial DNA was extracted and amplified with two arbitrary ten-mer primers, using the random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) technique. RAPD markers were separated by agarose gel electrophoresis, visualised with ethidium bromide, and then analysed for similarity using the GelCompar programme. The isolates were seen to fall into two major population groups. A high degree of genetic diversity was seen, with a total of 350 unique strains occurring amongst the 359 isolates. The majority of drug-resistant isolates grouped together in the smaller population group. The genetic data were also correlated with geographical locality. It was found that a slight preponderance of isolates that grouped together closely, vis. that were either genetically identical or very similar (similarity index of approximately 97%), were from areas that were considered to be geographically distant. Antibiotic resistance patterns were also examined, revealing a total of 16 different resistance profiles among the 68 drug-resistant isolates. RAPD-PCR has proved to be a cost- and time-effective technique, suitable for such a large-scale population genetics study. It has provided useful information on the genetic diversity of an organism which is responsible for an increasing amount of morbidity and mortality in South Africa's second-largest province.
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PMID:A study of the genetic diversity of Mycobacterium tuberculosis isolated from patients in the eastern province of South Africa using random amplified polymorphic DNA profiling. 937 24

We describe a test which uses the ability of viable cells to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to detect resistance to a bactericidal drug, rifampin, in in vitro-cultured Mycobacterium tuberculosis. The assay shows a linear relationship between the number of viable bacteria and the ability to reduce MTT. Dead mycobacteria were unable to reduce MTT. Rifampin-sensitive M. bovis (BCG) and M. tuberculosis exposed to rifampin showed a rifampin concentration-dependent inhibition of the ability to reduce MTT, while the resistant strains were unaffected. The inhibition of MTT reduction after treatment with rifampin paralleled the reduction in the number of CFU. By using mixing experiments in which the population percentages of rifampin-sensitive and -resistant strains were varied, the assay could detect the presence of rifampin resistance in the mixture when at least 1% of the bacterial population was composed of drug-resistant strains. The assay is cheap, can be visually read, and requires less than 3 days to obtain susceptibility results. The total time required to obtain results, from the time sputum is received in the laboratory, is, in most cases, less than 4 to 5 weeks, which is the time required for primary culture of the bacteria. The MTT assay could, in combination with a test to detect resistance to isoniazid, be a cheap and rapid screening method for multidrug-resistant M. tuberculosis that is affordable even by low-income countries where tuberculosis is a major public health problem.
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PMID:Use of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide for rapid detection of rifampin-resistant Mycobacterium tuberculosis. 957 79


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