Madhab K. Chattopadhyay

• M.Pharm, Ph.D
• Centre for Cellular and Molecular Biology

The adaptability of bacteria to extreme cold environments has been demonstrated from time to time by various investigators. Metabolic activity of bacteria at subzero temperatures is also evidenced. Recent studies indicate that bacteria continue both catabolic and anabolic activities at subzero temperatures. Implications of these findings are discus...

Antibiotics are chemotherapeutic agents, which have been a very powerful tool in the clinical management of bacterial diseases since the 1940s. However, benefits offered by these magic bullets have been substantially lost in subsequent days following the widespread emergence and dissemination of antibiotic resistant strains. While it is obvious tha...

Bacterial resistance to antibiotics poses a serious challenge to the prospect of chemotherapy. Rational use of antibiotics is most desirable but it cannot provide a permanent solution to the problem. In this article the biochemical and genetic basis of antibiotic resistance in bacteria is discussed with examples. The non-clinical aspects of antibio...

Association between cold stress and oxidative stress was demonstrated by measuring the activity of two antioxidant enzymes and the level of free radicals generated in two batches of cells of an Antarctic bacterium Pseudomonas fluorescens MTCC 667, grown at 22 and 4°C. Increase in oxidative stress in cells grown at low temperature was evidenced by i...

Although the imprudent use of antibiotics is considered to be a major reason behind the emergence and spread of antibiotic resistance,1 bacteria isolated from pristine environments show substantial tolerance to antibiotics. For example, bacterial strains from several genera isolated from different samples from the Antarctic (soil, fast ice, cyanoba...

Survival of bacteria at low temperatures provokes scientific interest because of several reasons. Investigations in this area promise insight into one of the mysteries of life science - namely, how the machinery of life operates at extreme environments. Knowledge obtained from these studies is likely to be useful in controlling pathogenic bacteria,...

Since, like other osmolytes, proline can act as a protein stabilizer, we investigated the thermoprotectant properties of proline in vitro and in vivo. In vivo, elevated proline pools in Escherichia coli (obtained by altering the feedback inhibition by proline of γ-glutamylkinase, the first enzyme of the proline biosynthesis pathway) restore the via...

Increase in the synthesis of membrane-fluidizing (such as unsaturated) fatty acids in cold-adapted bacteria is well documented. More recently, a polar carotenoid was found to rigidify synthetic membranes in an in vitro study. Enhanced biosynthesis of some fatty acids that increase membrane fluidity, and also of polar carotenoids has been evidenced...

The major carotenoid pigments of an Antarctic psychrotolerant bacterium, Sphingobacterium antarcticus, and a mesophilic bacterium, Sphingobacterium multivorum, were identified as zeaxanthin, &#35-cryptoxanthin, and &#35-carotene. Analysis was based on ultraviolet-visible spectroscopy, mass spectroscopy, and reversed-phase HPLC. Photoacoustic spectr...

Pigmentation in a psychrotrophic M.roseus was found to be increased when the bacteria were grown at 5 degrees C as compared to its pigmentation at 25 degrees C. In addition more polar pigments were synthesised at low temperature. The pigments were identified as bacterioruberins and were demonstrated to bind to synthetic membranes of phosphatidylcho...

The fluorescence excitation and emission spectra are reported for P-3 (bis-dehydro-B-carotene-2-carboxylic acid), the major carotenoid pigment of psychrotrophic M. roseus. The excitation spectrum and the absorption spectrum showed good agreement with respect to the position of their peak maxima. The study also demonstrates that P-3 binds to liposom...

Eight psychrotrophic strains belonging to four different genera were screened for the presence of cold-active alkaline phosphatase in sonicated cell homogenates. An approximately 1000-fold higher activity than E. coli was detected in two psychrotrophic strains of Sphingobacterium antarcticus and one mesophilic strain of Flavobacterium multivorum. T...

Water and soil samples from Schirmacher Oasis, Antarctica were found to contain a heterogenous group of psychrotrophic bacteria and yeasts. The bacteria belong to the genera Pseudomonas, Sphingobacterium, Micrococ- cus, Planococcus and Arthrobacter. The yeasts belong to the genera Rhodotor- ula, Bullera and Candida. Biochemical studies indicate tha...