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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A specific binding test was used to detect immune complexes containing antigens of Mycobacterium lepraemurium in the serum and tissues of infected mice. Complexes were precipitated by antiserum against immunoglogulin, free antigen removed by washing and the presence of bound antigen demonstrated by measurement of uptake of radioactively labelled specific antibody by the precipitate. Tests were done both with 125I-labelled FAB prepared from an immune from rabbit antiserum against M. Lepraemurium and with 125I-labelled IgG precipitate. Out of seventy-nine serum samples taken monthly up to the 5th month after infection, only there were positive (one at 2 months and two at 3 months). Kidneys taken from infected mice were also examined for immune complexes. Although deposits of IgM and sometimes of IgG were observed by immunoflourescence in glomeruli of normal mice, deposits of IgG were more frequent later on in infected mice. Nevertheless, binding tests done on acid eluates were positive in only one out of fifty-three infected mice.
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PMID:Detection of immune complexes in mice infected with Mycobacterium lepraemurium. 82 Apr 99

We described previously the unusual structures of the two major C-mycoside glycopeptidolipids from Mycobacterium fortuitum biovar. peregrinum. More polar glycolipids, potentially more interesting in terms of antigenicity, were also present in the strains. A combination of FAB mass spectrometry, NMR, chemical analyses, and radiolabeling was successfully applied to these glycolipids to arrive at the unexpected and novel structure for the more polar compound. This consisted of the "orthodox" basic structure of the apolar C-mycosides, modified at the alaninol end by the presence of a sulfate group on position 2 of a 3,4-di-O-methylrhamnosyl residue. This novel and second class of sulfate-containing mycobacterial glycolipid may provide a chemical basis for the differentiation and classification of members of the M. fortuitum complex, the main group causing human diseases among the many fast-growing mycobacteria widely distributed in nature.
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PMID:Structure of a novel sulfate-containing mycobacterial glycolipid. 144 49

Mycobacterium fortuitum, biovar, fortuitum, the cause of serious skin and soft-tissue infections, can be differentiated from M. fortuitum, biovar. peregrinum, and other rapidly growing opportunistic mycobacteria by the presence of a unique antigenic glycolipid. The glycolipid is among the simplest of the acyl-trehalose-containing lipooligosaccharide class. The application of 1H and 13C NMR, methylation analysis, FAB/MS, and other procedures demonstrated the structure, beta-D-Glcp-(1----6)-2-O-acyl-alpha-D-Glcp-(1 in equilibrium with 1)-3,4,6-tri-O-acyl-alpha-D-Glcp. Thus, practically all environmental mycobacteria, many of them opportunistic pathogens, can be differentiated serologically and chemically on the basis of unique sugar arrangements within a few classes of glycolipids. The simplicity of the structure in M. fortuitum fortuitum combined with the distinct roughness of the parent strain raises the intriguing possibility that it is a spontaneous rough variant of the other mycobacteria with more elaborate glycolipids.
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PMID:Characterization of the specific antigenicity of Mycobacterium fortuitum. 163 62

A low molecular weight antigen of Mycobacterium leprae and other mycobacteria was previously defined in our laboratory by means of IgG2a monoclonal antibody termed L4. The antigen had an apparent molecular mass of 4.5-6 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was assumed to be a glycoprotein on the basis of its staining with periodic acid Schiff and sensitivity to periodate treatment. In the present work, the cross-reactive and phospholipidic nature of the antigen, present in Mycobacterium tuberculosis as well as in M. leprae sonicates, was demonstrated and this enabled us to undertake its purification from crude M. tuberculosis phospholipidic extracts. The L4-reactive antigen from M. tuberculosis called L4-PIM, was purified by means of silicic acid high pressure liquid chromatography. Its characterization by gas chromatography and FAB-MS showed the antigen to be the common mycobacterial dimannosylated phosphatidylinositol (PIM2), the structure of which had been previously established by others (Lee, Y. C., and Ballou, C. E. (1964) J. Biol. Chem. 239, 1316-1327; Lee, Y. C., and Ballou, C. E. (1965) J. Biochem. (Tokyo) 4, 1395-1404). Delineation of the L4 epitope on M. tuberculosis L4-PIM revealed the involvement of the axial 2-hydroxyl of the alpha-D-mannosyl residues, without any detectable contribution from the myo-inositol. Consequently, L4 was shown to react with PIM5, the structure of which contains twice the number of epitopes as does PIM2. By using both immunostained thin layer chromatography and indirect enzyme-linked immunosorbent assay, similar L4-PIM epitopes were demonstrated in M. leprae sonicate, thereby explaining the cross-reactive nature of the L4-monoclonal antibody. Antibodies of IgG class directed against M. tuberculosis L4-PIM were detectable in sera from patients with leprosy, but no evidence of T cell reactivity to L4-PIM was obtained. The demonstration of a correlation of anti-L4-PIM IgG and anti-disacharide-conjugated bovine serum albumin IgM antibody titers in the sera of leprosy patients indicates that measurement of antibodies directed against L4-PIM may have the potential to be used as a complementary assay to the disaccharide-conjugated bovine serum albumin test for diagnosis and monitoring of patients undergoing leprosy therapy.
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PMID:Isolation and structural characteristics of a monoclonal antibody-defined cross-reactive phospholipid antigen from Mycobacterium tuberculosis and Mycobacterium leprae. 170 33

Strains from the Mycobacterium fortuitum complex contain surface species-specific lipids allowing their precise identification. In M. fortuitum biovar. peregrinum two major glycopeptidolipids, of the C-mycoside type, were characterized by a combination of chemical analyses, NMR, and FAB mass spectrometry. Important information was obtained by mass spectrometry both on their molecular weight and on the peptide and saccharide sequences without any derivatization. The basic structure of the two compounds was shown to be [formula: see text] The disaccharide part linked O-glycosidically to alaninol was either 3,4-di-O-methyl-alpha-L-rhamnopyranosyl (1----2) 3,4-di-O-methyl-alpha-L-rhamnopyranoside (mycoside I) or 3-O-methyl-alpha-L-rhamnopyranosyl (1----2) 3,4-di-O-methyl-alpha-L-rhamnopyranoside (mycoside II). This is an unusual structure of a C-mycoside since neither 6-deoxytalose nor its derivatives are present. Moreover, the oligosaccharide part is linked to the alaninol residue instead of the allo-threonine.
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PMID:Glycopeptidolipids from Mycobacterium fortuitum: a variant in the structure of C-mycoside. 193 76

A new non-phosphorylated lipoamino acid was extracted from Mycobacterium phlei, strain IST. It is particularly sensitive to alkaline hydrolysis, and contains a lysine residue joined to a 1,2-diglyceride via an ester linkage. The FAB-positive mass spectrum shows the presence of various molecular species of which the most abundant contains a palmitic and a tuberculostearic acid residue. An analogue of this lipid was synthesized, 1,2-dipalmitoyl 3-lysyl glycerol. Both its chromatographic behavior (TLC), and the decomposition pathways of the MH+ ions, studied by FAB MS and MIKE spectroscopy, were identical to the natural product.
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PMID:Isolation and structural characterization of a new non-phosphorylated lipoamino acid from Mycobacterium phlei. 324 May 62

The dipyruvylated glycolipid from Mycobacterium smegmatis (Saadat, S., and Ballou, C.E. (1983) J. Biol. Chem. 258, 1813-1818) has been shown to have the following structure in which FA1 is tetra- or hexadecanoic acid and FA2 is 2,4-dimethyl-2-eicosenoic acid. (formula; see text) The fast atom bombardment mass spectrum showed two major ions [M - H]- at m/z 1511 and 1539 (Mr 1512 and 1540) in a ratio of 1.4:1, suggesting that the glycolipid was a mixture of homologs that differed in fatty acid composition by 2 methylene groups. Analysis revealed C14, C16, and C22 fatty acids in ratios of 0.6:0.4:1.0, indicating that 60% of the molecules contained a C14 and C22 fatty acid whereas 40% contained a C16 and C22 fatty acid. The fragmentation pattern showed that a single glucose unit along with the smaller fatty acid could be lost to yield a tetrasaccharide with attached C22 fatty acid, and a second fragmentation yielded a trisaccharide containing 2 pyruvic acids but without attached fatty acid. The C14 and C16 fatty acids were identified as myristic and palmitic acid, whereas the C22 fatty acid was 2,4-dimethyl-2-eicosenoic acid. Precise localization of the fatty acids came from periodate oxidation and methylation analysis.
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PMID:Pyruvylated glycolipids from Mycobacterium smegmatis. Nature and location of the lipid components. 398 Apr 71

Three different mass spectrometric method suitable for the analysis of polyprenyl and dolichyl phosphates and their glycosylated forms are described. Fast atom bombardment mass spectrometry (FAB MS) of glycosyl monophosphopolyprenols produces negative ions characteristic of the intact molecule. Tandem mass spectrometry of (M-H)- anions allows the determination of masses of both glycosyl and lipid moieties. Thus, for example, FAB-MS/MS of a mixture of native glycosyl monophosphopolyprenols isolated from ethambutol-treated Mycobacterium smegmatis enabled us to detect two novel pentosyl monophosphopolyprenols. Two other methods are proposed for the analysis of prenyl phosphates, as these compounds do not produce fragments in FAB-MS/MS at low collisional energy. By Desorption Electron Impact ionization (DEI) an intense (M-H3PO4)+ ion as well as fragments corresponding to the successive loss of isoprene residues (68 Da) can be observed. Alternatively, Desorption Chemical Ionization yields ions corresponding to the loss of 66, 78 and 98 Da (i.e. of a part or the entire phosphate moiety) of a prenyl phosphate molecule. Tandem mass spectrometry of the (M-H-98)- ion gives a series of intense fragments differing by 68 mass units over the whole mass range.
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PMID:Mass spectrometric analysis of prenyl phosphates and their glycosylated forms. 785 6

Despite major advances in our understanding of the structure of mycobacterial cell walls, little is known of their biogenesis, and yet they are the site of action of many anti-tuberculosis drugs and implicated in much of the pathology of tuberculosis and leprosy. A family of monoglycosyl polyprenylphosphates was isolated from Mycobacterium smegmatis, containing arabinose, ribose, and mannose. The isoprenoid nature of the lipid components was established by 1H NMR, and fast atom bombardment mass spectroscopy (FAB-MS) demonstrated the presence of C50 decaprenyl-P derivatives and smaller amounts of the C35 octahydroheptaprenyl-P products. The configuration of the mycobacterial decaprenol was established as mono-trans, octa-cis, pointing to carriers of unusual structure. Combined gas chromatography (GC)/MS, FAB-MS/MS, and 1H NMR allowed characterization of one of the primary components as beta-D-arabinofuranosyl-1-monophosphodecaprenol. Pulse-chase metabolic labeling of cells with D-[14C]glucose indicated that the decaprenyl-P-arabinose is an active intermediate in the biosynthesis of the arabinan of cell wall arabinogalactan and arabinomannan. The identification of polyprenyl-P-ribose suggests the existence of ribose-containing polysaccharides in the cell walls of M. smegmatis or/and of a novel epimerase in the D-arabinose biosynthetic pathway. Ethambutol, a powerful anti-tuberculosis drug known to inhibit arabinogalactan and arabinomannan biosynthesis, results in the rapid accumulation of decaprenyl-P-arabinose, indicating that the drug interferes with either the transfer of arabinose from the donor or, alternatively, the synthesis of the arabinose acceptor itself.
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PMID:Recognition of the lipid intermediate for arabinogalactan/arabinomannan biosynthesis and its relation to the mode of action of ethambutol on mycobacteria. 808 38

The following incomplete structure, alpha-X-(1-->3)-[beta-L-Xylp-(1-->4)]6-3-O-Me-alpha-Rhap-(1- ->3)- beta-D-Galp-(1-->3)-beta-D-Glcp-(1-->4)-2-O-acyl-alpha-D-Glcp-(1<-->1)-4 ,6-di-O-acyl-alpha-D-Glcp, was previously established for the antigenic lipo-oligosaccharide typifying Mycobacterium gastri, namely, LOS-III. The partial structure of the distal monosaccharide (X) was assigned as 3,6-dideoxy-4-C-(1,3-di-O-methylpropyl)-alpha-hexopyranose, which corresponds to a new-found monosaccharide in nature [Gilleron M., Vercauteren J., & Puzo G. (1993) J. Biol. Chem. 268, 3168-3179]. This article reports the complete structure of X, which was determined from the FAB-MS and 2D NMR analysis of the peracetylated LOS-III. The comparative analyses of the native and per-O-acetylated LOS-III FAB-MS spectra revealed, for the monosaccharide X, a molecular mass of 370 Da and five hydroxyl groups that could be acetylated. Additionally, the 1D 1H NMR spectrum of the per-O-acetylated LOS-III showed a dramatically increased dispersion of the protons, which resonated between 3 and 4 ppm in the spectrum of the underivatized LOS-III. Thus, thanks to 2D NMR sequences (COSY, HOHAHA, HMQC, HMQC-HOHAHA, and HMBC), the complete assignment of the 1H and 13C signals was achieved. Starting from the quaternary C4 resonance, the spin system of the C-alkyl chain was assigned, allowing us to propose the following structure, 3,6-dideoxy-4-C-(1,3-dimethoxy-4,5,6,7-tetrahydroxyheptyl)-alpha-x ylo- hexopyranose. The xylo configuration was established from the ROESY spectrum.
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PMID:Lipo-oligosaccharidic antigen from Mycobacterium gastri. Complete structure of a novel C4-branched 3,6-dideoxy-alpha-xylo-hexopyranose. 811 Jul 98


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