Dipankar Chatterji

Learn More
Adaptation to any undesirable change in the environment dictates the survivability of many microorganisms, with such changes generating a quick and suitable response, which guides the physiology of bacteria. During nutritional deprivation, bacteria show a stringent response, as characterized by the accumulation of (p)ppGpp, resulting in the repression of(More)
Microbial adaptation to environmental stress plays an important role in survival. It is necessary to understand the mechanisms underlying the survival of microbes under stress, as they may eventually aid in the successful control of the growth and persistence of these organisms. During nutrient starvation, Escherichia coli elicits a stringent response to(More)
The rpoZ gene for the omega subunit of Escherichia coli RNA polymerase constitutes single operon with the spoT gene, which is responsible for the maintenance of stringent response under nutrient starvation conditions. To identify the physiological role of the omega subunit, we compared the gene expression profile of wild-type Escherichia coli with that of(More)
Almost one-third of the world population today harbors the tubercle bacillus asymptomatically. It is postulated that the morphology and staining pattern of the long-term persistors are different from those of actively growing culture. Interestingly, it has been found that the morphology and staining pattern of the starved in vitro population of mycobacteria(More)
Some members of the DNA-binding protein from stationary phase cells (Dps) family of proteins have been shown to play an important role in protecting microorganisms from oxidative or nutritional stress. Dps homologs have been identified in various bacteria such as Escherichia coli, Bacillus subtilis, and Listeria innocua. Recently we have reported the(More)
The omega subunit, the smallest subunit of bacterial RNA polymerase, is known to be involved in maintaining the conformation of the beta' subunit and aiding its recruitment to the rest of the core enzyme assembly in Escherichia coli. It has recently been shown in Mycobacterium smegmatis, by creating a deletion mutation of the rpoZ gene encoding omega, that(More)
Omega (omega) is the smallest subunit of bacterial RNA polymerase (RNAP). Although identified early in RNAP research, its function remained ambiguous and shrouded by controversy for a considerable period. It has subsequently been shown that the protein has a structural role in maintenance of the conformation of the largest subunit, beta', and recruitment of(More)
During active growth of Escherichia coli, majority of the transcriptional activity is carried out by the housekeeping sigma factor (sigma(70)), whose association with core RNAP is generally favoured because of its higher intracellular level and higher affinity to core RNAP. In order to facilitate transcription by alternative sigma factors during nutrient(More)
In the noninfectious soil saprophyte Mycobacterium smegmatis, intracellular levels of the stress alarmones guanosine tetraphosphate and guanosine pentaphosphate, together termed (p)ppGpp, are regulated by the enzyme Rel(Msm). This enzyme consists of a single, bifunctional polypeptide chain that is capable of both synthesizing and hydrolyzing (p)ppGpp. The(More)
We have reported previously that the long-term survival of Mycobacterium smegmatis is facilitated by a dual-active enzyme MSDGC-1 (renamed DcpA), which controls the cellular turnover of cyclic diguanosine monophosphate (c-di-GMP). Most mycobacterial species possess at least a single copy of a DcpA orthologue that is highly conserved in terms of sequence(More)