scholarly journals Conditional Sigma Factor Expression, Using the Inducible Acetamidase Promoter, Reveals that the Mycobacterium tuberculosis sigF Gene Modulates Expression of the 16-Kilodalton Alpha-Crystallin Homologue

1999 ◽  
Vol 181 (24) ◽  
pp. 7629-7633 ◽  
Author(s):  
Yukari C. Manabe ◽  
Jong Min Chen ◽  
Chiew G. Ko ◽  
Ping Chen ◽  
William R. Bishai
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Bovis ◽  
Sigma Factor ◽  
Fusion Gene ◽  
Two Dimensional ◽  
Alpha Crystallin ◽  
Protein Gel ◽  
Factor Expression

ABSTRACT A chemically inducible acetamidase promoter-sigF fusion gene was integrated into the chromosome of Mycobacterium bovis BCG. Two-dimensional protein gel analysis permitted the identification of a number of protein spots whose expression was SigF related. One spot upregulated by inappropriate induction ofsigF expression corresponded to the 16-kDa antigen alpha-crystallin.

scholarly journals Global transcriptional response to vancomycin in Mycobacterium tuberculosis

Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1093-1102 ◽  
Author(s):  
Roberta Provvedi ◽  
Francesca Boldrin ◽  
Francesco Falciani ◽  
Giorgio Palù ◽  
Riccardo Manganelli
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Surface Stress ◽  
Sigma Factor ◽  
Clustering Analysis ◽  
Transcriptional Response ◽  
Alternative Sigma Factor ◽  
Hierarchical Clustering Analysis ◽  
Physiological Mechanisms ◽  
Basal Resistance ◽  
Antibacterial Drugs

In order to gain additional understanding of the physiological mechanisms used by bacteria to maintain surface homeostasis and to identify potential targets for new antibacterial drugs, we analysed the variation of the Mycobacterium tuberculosis transcriptional profile in response to inhibitory and subinhibitory concentrations of vancomycin. Our analysis identified 153 genes differentially regulated after exposing bacteria to a concentration of the drug ten times higher than the MIC, and 141 genes differentially expressed when bacteria were growing in a concentration of the drug eightfold lower than the MIC. Hierarchical clustering analysis indicated that the response to these different conditions is different, although with some overlap. This approach allowed us to identify several genes whose products could be involved in the protection from antibiotic stress targeting the envelope and help to confer the basal level of M. tuberculosis resistance to antibacterial drugs, such as Rv2623 (UspA-like), Rv0116c, PE20-PPE31, PspA and proteins related to toxin–antitoxin systems. Moreover, we also demonstrated that the alternative sigma factor σ E confers basal resistance to vancomycin, once again underlining its importance in the physiology of the mycobacterial surface stress response.

scholarly journals Structural features of the exocellular polysaccharides of Mycobacterium tuberculosis

1994 ◽  
Vol 297 (2) ◽  
pp. 351-357 ◽  
Author(s):  
A Lemassu ◽  
M Daffé
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Molecular Mimicry ◽  
Degradation Products ◽  
Cell Envelope ◽  
Gel Filtration ◽  
Structural Features ◽  
Two Dimensional ◽  
Phagocytic Cells ◽  
Molecular Masses ◽  
Branched Structure

The cell envelope which surrounds pathogenic mycobacteria is postulated to be a defence barrier against phagocytic cells and its outermost constituents have a tendency to accumulate in the culture medium. The present work demonstrates that the exocellular material of Mycobacterium tuberculosis contains large amounts of polysaccharides with only traces, if any at all, of lipids. Three types of polysaccharides were purified by anion-exchange and gel-filtration chromatography; all were found to be neutral compounds devoid of acyl substituents. They consisted of D-glucan, D-arabino-D-mannan and D-mannan, which were eluted from gel-filtration columns in positions corresponding to molecular masses of 123, 13 and 4 kDa respectively. Their predominant structural features were determined by the characterization of the per-O-methyl derivatives of enzymic, acetolysis and Smith-degradation products and by 1H- and 13C-n.m.r. spectroscopy of the purified polysaccharides, using mono- and two-dimensional homonuclear chemical-shift correlated spectroscopy and two-dimensional heteronuclear (1H/13C) spectroscopy. The glucan which represented up to 90% of the polysaccharides was composed of repeating units of five or six-->4-alpha-D-Glcp-1--> residues and a -->4-alpha-D-Glcp substituted at position 6 with an alpha-D-Glcp, indicating a glycogen-like highly branched structure not related to the so-called polysaccharide-II previously identified in tuberculin. The arabinomannan consisted of a mannan segment composed of a -->6-alpha-D-Man-1--> core substituted at some positions 2 with an alpha-D-Manp. The arabinan termini of the arabinomannan were found to be extensively capped with mannosyl residues. The possibility that these polysaccharides contribute to the persistence of the tubercle bacillus in the macrophage by molecular mimicry is discussed.

scholarly journals Protection Elicited by Two Glutamine Auxotrophs of Mycobacterium tuberculosis and In Vivo Growth Phenotypes of the Four Unique Glutamine Synthetase Mutants in a Murine Model

2006 ◽  
Vol 74 (11) ◽  
pp. 6491-6495 ◽  
Author(s):  
Sunhee Lee ◽  
Bo-Young Jeon ◽  
Svetoslav Bardarov ◽  
Mei Chen ◽  
Sheldon L. Morris ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Glutamine Synthetase ◽  
Mycobacterium Bovis ◽  
Murine Model ◽  
Triple Mutant ◽  
Auxotrophic Mutants ◽  
Bcg Vaccination ◽  
In Vivo Growth ◽  
Subcutaneous Immunization

ABSTRACT We generated four individual glutamine synthetase (GS) mutants (ΔglnA1, ΔglnA2, ΔglnA3, and ΔglnA4) and one triple mutant (ΔglnA1EA2) of Mycobacterium tuberculosis to investigate the roles of GS enzymes. Subcutaneous immunization with the ΔglnA1EA2 and ΔglnA1 glutamine auxotrophic mutants conferred protection on C57BL/6 mice against an aerosol challenge with virulent M. tuberculosis, which was comparable to that provided by Mycobacterium bovis BCG vaccination.

Catalytic ferromagnetic gold nanoparticle immunoassay for the detection and differentiation of Mycobacterium tuberculosis and Mycobacterium bovis

2021 ◽  
pp. 339037
Author(s):  
Brendan Gilbride ◽  
Gustavo Marçal Schmidt Garcia Moreira ◽  
Michael Hust ◽  
Cuong Cao ◽  
Linda Stewart
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Gold Nanoparticle ◽  
Mycobacterium Bovis
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