Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structures of the hydrophilic parietal and cellular arabinomannans isolated from Mycobacterium bovis BCG cell wall [Nigou et al. (1997) J Biol Chem 272: 23094-103] were investigated. Their molecular mass as determined by MALDI-TOF mass spectrometry was around 16 kDa. Concerning cap structure, capillary electrophoresis analysis demonstrated that dimannoside (Manpalpha1-->2Manp) was the most abundant motif (65-75%). Using two-dimensional 1H-13C NMR spectroscopy, the mannan core was unambiguously demonstrated to be composed of -->6Manpalpha1--> backbone substituted at some O-2 by a single Manp unit. The branching degree was determined as 84%. Finally, arabinomannans were found to be devoid of the phosphatidyl-myo-inositol anchor and, by aminonaphthalene disulfonate tagging, the mannan core was shown to contain a reducing end. This constitutes the main difference between arabinomannans and lipoarabinomannans from Mycobacterium bovis BCG.
 ...
PMID:Structural definition of arabinomannans from Mycobacterium bovis BCG. 1057 94

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) associated with capillary electrophoresis (CE) has been used for structural characterization of mannooligosaccharide caps from Mycobacterium tuberculosis H37rv mannosylated lipoarabinomannans (ManLAMs). The mannooligosaccharide caps were released by mild acid hydrolysis, labeled with 1-aminopyrene-3,6,8-trisulfonate (APTS) prior to being separated by CE, collected, and analyzed by MALDI-TOF-MS and post-source decay experiments. This approach was optimized using standard APTS-labeled oligosaccharides. With the selected (9:1) mixture of 2,5-dihydroxybenzoic acid (DHB) and 5-methoxysalicylic acid (MSA) as matrix and the on-probe sample cleanup procedure with cation-exchange resin, standard APTS-maltotriose was successfully detected down to 50 fmol using linear-mode negative MALDI-TOF-MS. Moreover, using extraction delay time, only 100 and 500 fmol of this standard were required, respectively, to obtain accurate reflectron mass measurements and sequence determination through post-source decay experiments. Applied to only 5 microg (294 pmol) of M. tuberculosis ManLAMs, this analytical approach allowed successful mass characterization of the mannooligosaccharide cap structures from the deprotonated molecular ions [M - H]- and the y-type ion fragments obtained in post-source decay experiments. This powerful analytical approach opens new insights into both the characterization of oligosaccharides and the capping motifs displayed by ManLAMs purified from mycobacteria isolated from tubercular patients without in vitro culturing.
 ...
PMID:Structural characterization of Mycobacterium tuberculosis lipoarabinomannans by the combination of capillary electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. 1139 59

We have identified and characterised in several strains of Mycobacterium tuberculosis a new 5-methylthiopentose substituent on lipoarabinomannan (LAM). The 5-methylthiopentose was initially observed in heteronuclear (1)H-(13)C-NMR spectra of intact, (13)C-enriched LAM. Oligosaccharides carrying this substituent were released from (13)C-enriched LAM and from unlabelled LAM using an endo-arabinanase from Cellulomonas gellida. The presence of the methylthio group in these oligosaccharides was established using NMR, high-resolution Fourier-transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry using a Q-TOF mass spectrometer. The 5-methylthiopentose is linked to a terminal mannose in the cap structures of these oligosaccharides as evidenced by tandem mass spectrometry and by NMR. We suggest interference with the signal transduction mechanisms of infected macrophages as a possible function for this newly discovered LAM substituent.
 ...
PMID:5-Methylthiopentose: a new substituent on lipoarabinomannan in Mycobacterium tuberculosis. 1182 5

A series of trehalose-based oligosaccharides were isolated from the cytoplasmic fraction of Mycobacterium smegmatis and purified by gel-filtration and paper chromatography and TLC. Their structures were determined by HPLC and GLC to determine sugar composition and ratios, MALDI-TOF MS to measure molecular mass, methylation analysis to determine linkages, (1)H-NMR to obtain anomeric configurations of glycosidic linkages, and exoglycosidase digestions followed by TLC to determine sequences and anomeric configurations of the monosaccharides. Six different oligosaccharides were identified all with trehalose as the basic structure and additional glucose or galactose residues attached in various linkages. One of these oligosaccharides is the disaccharide trehalose (Glcalpha1-1alphaGlc), which is present in substantial amounts in these cells and also in other mycobacteria. Two other oligosaccharides, the tetrasaccharides Glcalpha1-4Glcalpha1-1alphaGlc6-1alphaGal and Galalpha1-6Galalpha1-6Glcalpha1-1alphaGlc, have not previously been isolated from natural sources or synthesized chemically. The fourth oligosaccharide, Glcbeta1-6Glcbeta1-6Glcalpha1-1alphaGlc, has been isolated from corynebacteria, but not reported in other organisms. Two other oligosaccharides, Glcalpha1-4Glcalpha1-1alphaGlc, which has been synthesized chemically and isolated from insects but not previously reported in mycobacteria, and Glcbeta1-6Glcalpha1-1alphaGlc, which was previously isolated from Mycobacterium fortuitum and yeast, were also characterized. Another trisaccharide found in the cytosol has been partially characterized as arabinosyl-1-4trehalose, but neither the anomeric configuration nor the D or L configuration of the arabinose is known. In analogy with sucrose and its higher homologs, raffinose and stachyose, which may act as protective agents during maturation drying in plants, these trehalose homologs may also have a protective role in mycobacteria, perhaps during latency.
 ...
PMID:Trehalose-based oligosaccharides isolated from the cytoplasm of Mycobacterium smegmatis. Relation to trehalose-based oligosaccharides attached to lipid. 1208 54

Purification and characterization of individual antigenic proteins are essential for the understanding of the pathogenic mechanisms of mycobacteria and the immune response against them. In the present study, we used anion-exchange chromatography to fractionate cell extracts and culture supernatant proteins from Mycobacterium bovis to identify T-cell-stimulating antigens. These fractions were incubated with peripheral blood mononuclear cells (PBMC) from M. bovis-infected cattle in lymphoproliferation assays. This procedure does not denature proteins and permits the testing of mixtures of potential antigens that could be later identified. We characterized protein fractions with high stimulation indices from both culture supernatants and cell extracts. Proteins were identified by two-dimensional gel electrophoresis followed by N-terminal sequencing or MALDI-TOF. Culture supernatant fractions containing low molecular weight proteins such as ESAT6 and CFP10 and other proteins (85B, MPB70), and the novel antigens TPX and TRB-B were associated with a high stimulation index. These results reinforce the concept that some low molecular weight proteins such as ESAT6 and CFP10 play an important role in immune responses. Also, Rv3747 and L7/L12 were identified in high stimulation index cell extract fractions. These data show that protein fractions with high lymphoproliferative activity for bovine PBMC can be characterized and antigens which have been already described and new protein antigens can also be identified in these fractions.
 ...
PMID:Identification of Mycobacterium bovis antigens by analysis of bovine T-cell responses after infection with a virulent strain. 1457 8

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) after base-specific cleavage of PCR amplified and in vitro-transcribed 16S rRNA gene (rDNA) was used for the identification of mycobacteria. Full-length 16S rDNA reference sequences of 12 type strains of Mycobacterium spp. frequently isolated from clinical specimens were determined by PCR, cloning, and sequencing. For MALDI-TOF MS-based comparative sequence analysis, mycobacterial 16S rDNA signature sequences ( approximately 500 bp) of the 12 type strains and 24 clinical isolates were PCR amplified using RNA promoter-tagged forward primers. T7 RNA polymerase-mediated transcription of forward strands in the presence of 5-methyl ribo-CTP maximized mass differences of fragments generated by base-specific cleavage. In vitro transcripts were subsequently treated with RNase T1, resulting in G-specific cleavage. Sample analysis by MALDI-TOF MS showed a specific mass signal pattern for each of the 12 type strains, allowing unambiguous identification. All 24 clinical isolates were identified unequivocally by comparing their detected mass signal pattern to the reference sequence-derived in silico pattern of the type strains and to the in silico mass patterns of published 16S rDNA sequences. A 16S rDNA microheterogeneity of the Mycobacterium xenopi type strain (DSM 43995) was detected by MALDI-TOF MS and later confirmed by Sanger dideoxy sequencing. In conclusion, analysis of 16S rDNA amplicons by MS after base-specific cleavage of RNA transcripts allowed fast and reliable identification of the Mycobacterium tuberculosis complex and ubiquitous mycobacteria (mycobacteria other than tuberculosis). The technology delivers an open platform for high-throughput microbial identification on the basis of any specific genotypic marker region.
 ...
PMID:Novel mass spectrometry-based tool for genotypic identification of mycobacteria. 1471 74

The sequence of the gene from Nocardia sp. NRRL 5646 encoding GTP cyclohydrolase I (GCH), gch, and its adjacent regions was determined. The open reading frame of Nocardia gch contains 684 nucleotides, and the deduced amino acid sequence represents a protein of 227 amino acid residues with a calculated molecular mass of 24,563Da. The uncommon start codon TTG was identified by matching the N-terminal amino acid sequence of purified Nocardia GCH with the deduced amino acid sequence. A likely ribosomal binding site was identified 9bp upstream of the translational start site. The 3' end flank region encodes a peptide that shares high homology with dihydropteroate synthases. Nocardia GCH has 73 and 60% identity to the proteins encoded by the putative gch of Mycobacterium tuberculosis and Streptomyces coelicolor, respectively. Nocardia GCH was highly expressed in Escherichia coli cells carrying a pHAT10 based expression vector, and moderately expressed in Mycobacterium smegmatis cells carrying a pSMT3 based expression vector. Enterokinase digestion of recombinant Nocardia GCH, and in-gel digestion of Nocardia GCH and recombinant GCH followed by MALDI-TOF-MS analysis, confirmed that the actual subunit size of the enzyme was 24.5kDa. Thus, we conclude that the active form of native Nocardia GCH is a decamer. Our earlier incorrect conclusion was that the native enzyme was an octamer derived from the anomalous SDS-PAGE migration of the subunit.
 ...
PMID:Cloning, expression, purification, and characterization of Nocardia sp. GTP cyclohydrolase I. 1513 90

We present a method for mining unannotated or annotated genome sequences with proteomic data to identify open reading frames. The region of a genome coding for a protein sequence is identified by using information from the analysis of proteins and peptides with MALDI-TOF mass spectrometry. The raw genome sequence or any unassembled contigs of an organism are theoretically cleaved into a number of equal sized but overlapping fragments, and these are then translated in all six frames into a series of virtual proteins. Each virtual protein is then subjected to a theoretical enzymatic digestion. Standard proteomic sample preparation methods are used to separate, array, and digest the proteins of interest to peptides. The masses of the resulting peptides are measured using mass spectrometry and compared to the theoretical peptide masses of the virtual proteins. The region of the genome responsible for coding for a particular protein can then be identified when there are a large number of hits between peptides from the protein and peptides from the virtual protein. The method makes no assumptions about the location of a protein in a particular gene sequence or the positions or types of start and stop codons. To illustrate this approach, all 773 proteins of Pseudomonas aeruginosa contained in SWISS-PROT were used to theoretically test the method and optimize parameters. Increasing the size of the virtual proteins results in an overall improvement in the ability to detect the coding region, at the cost of decreasing the sensitivity of the method for smaller proteins. Increasing the minimum number of matching peptides, lowering the mass error tolerance, or increasing the signal-to-noise ratio of the simulated mass spectrum, improves the ability to detect coding regions. The method is further demonstrated on experimental data from Mycobacterium tuberculosis and is also shown to work with eukaryotic organisms (e.g., Homo sapiens).
 ...
PMID:Using proteomics to mine genome sequences. 1525 19

Current methods for the identification of mycobacteria in culture are time-consuming, requiring as long as 12 weeks for positive identification. One potential approach to rapid mycobacterial identification is to utilize proteomic profiling of cultures by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In this report, we have applied MALDI-TOF MS to proteomic profiling of cultured microorganisms representing six species of the genus Mycobacterium. We find that analysis of acetonitrile/trifluoroacetic acid cellular extracts produces data similar to that of the analysis of deposited whole cells, while minimizing human contact with the microorganisms and rendering them nonviable. A matrix composition of alpha-cyano-4-hydroxycinnamic acid with fructose yields highly reproducible MALDI-TOF spectra. Statistical analysis of MALDI-TOF MS data allows differentiation of each individual mycobacterial species on the basis of unique mass fingerprints. The methodology allows identification of a number of unique (potentially diagnostic) biomarkers as targets for protein identification by MS/MS experiments. In addition, we observe a number of signals common to all mycobacterial species studied by MALDI-TOF MS, which may be genus-specific biomarkers. The potentially genus-specific biomarkers occur at low mass (<2 kDa) and are likely to be lipids and cell wall components such as mycolic acids. This study demonstrates the potential for mass spectrometry-based identification/classification of mycobacteria.
 ...
PMID:Proteomic profiling of intact mycobacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. 1545 97

Data are presented from two-dimensional (2-D) PAGE analysis of Mycobacterium tuberculosis strain Harlingen grown during aerobic and anaerobic culture, according to a modified Wayne dormancy model. M. tuberculosis cultures were grown to the transition point between exponential growth and stationary phase in the presence of oxygen (7 days) and then part of the cultures was shifted to anaerobic conditions for 16 days. Growth declined similarly during aerobic and anaerobic conditions, whereas the ATP consumption rapidly decreased in the anaerobic cultures. 2-D PAGE revealed 50 protein spots that were either unique to, or more abundant during, anaerobic conditions and 16 of these were identified by MALDI-TOF. These proteins were the alpha-crystalline homologue (HspX), elongation factor Tu (Tuf), GroEL2, succinyl-CoA : 3-oxoacid-CoA transferase (ScoB), mycolic acid synthase (CmaA2), thioredoxin (TrxB2), beta-ketoacyl-ACP synthase (KasB), l-alanine dehydrogenase (Ald), Rv2005c, Rv2629, Rv0560c, Rv2185c and Rv3866. Some protein spots were found to be proteolytic fragments, e.g. HspX and GroEL2. These data suggest that M. tuberculosis induces expression of about 1 % of its genes in response to dormancy.
 ...
PMID:Comparative proteome analysis of Mycobacterium tuberculosis grown under aerobic and anaerobic conditions. 1552 67


1 2 3 4 5 6 7 8 9 10 Next >>