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The devR-devS two-component system of Mycobacterium tuberculosis was identified earlier and partially characterized in our laboratory. A devR::kan mutant of M. tuberculosis was constructed by allelic exchange. The devR mutant strain showed reduced cell-to-cell adherence in comparison to the parental strain in laboratory culture media. This phenotype was(More)
OBJECTIVES To develop simple, rapid, low-cost and robust assays for screening drugs against dormant and actively growing mycobacteria. METHODS Actively growing aerobic and hypoxia-adapted dormant cultures of Mycobacterium tuberculosis, Mycobacterium bovis BCG and Mycobacterium smegmatis were tested for susceptibility to standard antimicrobial drugs by(More)
Definitive and rapid diagnosis of extrapulmonary tuberculosis is challenging since conventional techniques have limitations. We have developed a universal sample processing (USP) technology for detecting mycobacteria in clinical specimens. In this study, this technology was evaluated blindly on 99 extrapulmonary specimens collected from 87 patients.(More)
The importance of inter- and intracellular signal transduction in all forms of life cannot be underestimated. A large number of genes dedicated to cellular signalling are found in almost all sequenced genomes, and Mycobacteria are no exception. What appears to be interesting in Mycobacteria is that well characterized signalling mechanisms used by bacteria,(More)
The prompt diagnosis of smear-negative cases is a prerequisite to controlling tuberculosis (TB). Several new laboratory approaches, including nucleic acid amplification (NAA), are being evaluated in various disease settings to meet this challenge. However, NAA needs simplification before it is widely accepted. Furthermore, a supporting smear result improves(More)
DevR regulon function is believed to be crucial for the survival of Mycobacterium tuberculosis during dormancy. In this study, we undertook a comprehensive analysis of the DevR regulon. All the regulon promoters were assigned to four classes based on the number of DevR binding sites (Dev boxes). A minimum of two boxes are essential for complete interaction(More)
We have transferred DNa to Chinese hamster ovary (CHO) cells by DNA-mediated transformation. CHO tk- cells were transformed with the clones gene for herpes simplex virus thymidine kinase (HSV-tk) and were found to have a 50-fold lower frequency of transformation than mouse Ltk- cells at the same DNA dosage. By altering the amount of tk gene and carrier DNA(More)
Under hypoxic conditions or upon exposure to low concentrations of nitric oxide, DevR transcriptional regulator mediates the activation of approximately 50 genes that are believed to assist in dormancy development in Mycobacterium tuberculosis. Most of the strongly induced genes are characterized by the presence of one to four copies of a Dev box-like(More)
Two-component systems play a central role in the adaptation of pathogenic bacteria to the environment prevailing within host tissues. The genes encoding the response regulator DevR (Rv3133c/DosR) and the cytoplasmic portion (DevS(201)) of the histidine kinase DevS (Rv3132c/DosS), a putative two-component system of Mycobacterium tuberculosis, were cloned and(More)
The universal sample processing (USP) multipurpose methodology was developed for the diagnosis of tuberculosis (TB) and other mycobacterial diseases by using smear microscopy, culture, and PCR (S. Chakravorty and J. S. Tyagi, J. Clin. Microbiol. 43:2697-2702, 2005). Its performance was evaluated in a blinded study of 571 sputa and compared with that of the(More)