Isoniazid, is the only antituberculous drug for which the relation between lack of virulence and acquisition of resistance was associated. INH-resistant mutants were shown to contain defective katG gene. Classical studies showed that INH-resistant south Indian isolates have lower virulence in guinea pigs and higher susceptibility to H2O2. It is of interest to assess the virulence in south India...

isoniazid, is the only antituberculous drug for which the relation between lack of virulence and acquisition of resistance was associated. inh-resistant mutants were shown to contain defective katg gene. classical studies showed that inh-resistant south indian isolates have lower virulence in guinea pigs and higher susceptibility to h2o2. it is of interest to assess the virulence in south india...

Mycobacterium tuberculosis KatG catalyzes the activation of the antitubercular agent isoniazid to yield an inhibitor targeting enoyl reductase (InhA). However, no firm biochemical link between many KatG variants and isoniazid resistance has been established. In the present study, six distinct KatG variants identified in clinical Mycobacterium tuberculosis isolates resistant to isoniazid were ge...

In order to probe the structure and function of the mycobacterial catalase-peroxidase enzyme (KatG), we employed a genetic approach using dominant-negative analysis of katG merodiploids. Transformation of Mycobacterium bovis BCG with various katG point mutants (expressed from low-copy-number plasmids) resulted in reductions in peroxidase and catalase activities as measured in cell extracts. The...

Altered drug binding may be an important factor in isoniazid (INH) resistance, rather than major changes in the enzyme’s activity as a catalase or peroxidase (KatG). The identification of structural or functional defects in the mutant KatGs responsible for INH resistance remains as an area to be explored. In this connection, the differences in the binding affinity between wild-type (WT) and mut...

Title of Document: A NEW INSIGHT INTO MYCOBACTERIUM RESISTANCE TO REACTIVE OXYGEN INTERMEDIATES. Rabab Kish, Master of Science, 2006 Directed By: Dr. Lian-Yong Gao, Department of Cell Biology & Molecular Genetics The genes encoded by the RD1 locus are known to be important for intracellular survival of pathogenic mycobacterium, however their role in counteracting host defense is not known. I hy...

Caulobacter crescentus is an obligate aerobe which is exposed to high concentrations of photosynthetic oxygen and low levels of nutrients in its aquatic environment. Physiological studies of oxidative and starvation stresses in C. crescentus were undertaken through a study of lacZ fusion and null mutant strains constructed from the cloned 5' end of katG, encoding a catalase-peroxidase. The katG...

The CDC classifies Francisella tularensis as a Category A bioterrorism agent. Due to the risk of potential release antibiotic-resistant F. strains, new therapeutics against must be developed. Resazomycins are resazurin (Rz)-based compounds that exhibit antimicrobial activity and other gram-negative bacteria. mode action resazomycins is not understood, but targets antibiotic were identified in h...