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Articles by Shaon Ray Chaudhuri
Total Records ( 6 ) for Shaon Ray Chaudhuri
  Sanhita Chowdhury , Madhusmita Mishra , V.K. Adarsh , Anindita Mukherjee , Ashoke Ranjan Thakur and Shaon Ray Chaudhuri
  Nine bacterial isolates were screened from different sites of East Calcutta Wetland, an ecosystem located at the eastern fringes of Calcutta. Other than being a biodiversity rich area, the important feature of this system is that it is a natural sewage treatment plant for the city of Calcutta. In addition to daily sewage including solid and soluble wastes, a considerable load of toxic metals are released into the water bodies from industries, tanneries, agriculture, household as well as health sectors. Screening out microbes from such an environment was done keeping in mind their multi functional application. These bacterial isolates were found to produce extracellular protease which is known to have vast applications in the commercial market of enzymes. The key area of this study is exploring the role of these isolates in heavy metal remediation. These isolates were found to tolerate heavy metals like Ag, Al, Cu, Cr, Co, Ni and Pb. Energy Dispersive X Ray Fluorescence (EDXRF) analysis and Transmission Electron Microscopy of the metal treated cells confirm the intracellular accumulation. Moreover, a preliminary demonstration of the effect of metal induced stress on cell surface features was determined by Scanning Electron Microscopy.
  Arunava Pradhan , Pranami Bhaumik , Sumana Das , Madhusmita Mishra , Sufia Khanam , Bilqis Amin Hoque , Indranil Mukherjee , Ashoke Ranjan Thakur and Shaon Ray Chaudhuri
  Waste water fed fisheries are a common feature in different parts of the world. Yet not all work as efficiently as those operating at East Calcutta Wetland for more than 70 years now. The objective of this study is to unravel the reason for the markedly greater efficiency of the Bheris in fish production compared to other water bodies like rain water ponds or sewage fed fish ponds elsewhere. The study indicates that plankton growth could be an important factor responsible for greater fish production in the Bheris. The architecture of the Bheri itself acts as a facilitator in the process. It is proposed that planktons can act as biomarker for water quality assessment in fish production.
  Sanhita Chowdhury , Anindita Chakraborty , Ashoke Ranjan Thakur and Shaon Ray Chaudhuri
  Problem Statement: This study was an attempt to isolate anaerobic microbes with potential for DNA double strand break repair using methanogen specific medium (DSMZ 120) from East Calcutta Wetland in India. It also intended to verify the specificity of the medium for isolation of the desired family of microbe. Approach: Culture based technique was used to obtain the pure isolate that was further characterized in details. For double strand break repair studies, isolate was irradiated with different doses of 60Co gamma rays and its subsequent repair was observed using pulse field gel electrophoresis and asymmetric field inversion gel electrophoresis. Inhibitor was used to predict the mechanism of repair. Results: In this study we isolated and characterized a metal sensitive anaerobic microbial strain obtained using methanogen specific medium (DSMZ 120) from East Calcutta Wetland in India. The strain was one of the members of the group of uncultivated bacterium as evident from phylogenetic analysis, thus indicating the successful cultivation of an as yet uncultivable novel microbe (GenBank Acc. No. FJ 930097) and also the non-specific growth of microbes in prescribed medium. It was a Gram positive Bacilli, member of Fermicutes with optimum growth at 25°C and pH-7. The growth curve analysis showed a lag phase up to 24 h, log phase from 24-48 h, an early stationary phase from 96 h onwards. The strain could repair the DNA double strand break caused by irradiation with 60Co γ rays. The dose profile study revealed maximum repair at 60 Grays and thereafter a drop in repair ability with increase in irradiation dose. The time required for repair showed an essential incubation period of 4 h. The DNA polymerase inhibitor, Arabinose CTP inhibited the repair indicating the involvement of polymerase in the repair process and thus pointing towards homologous recombination as the underlying mechanism. Conclusion: In this study we were able to cultivate an as yet uncultivable anaerobic bacterial isolate and predict the growth conditions for the isolate. On irradiation with 60Co γ rays the isolate showed maximum repair following 60 Gray damage. DNA polymerase inhibitor arabinose CTP inhibited the repair mechanism completely. This indicated that DNA polymerase took active part in repair process and thus the mechanism was that of homologous recombination repair.
  Poonam Nasipuri , Gauri G. Pandit , Ashoke Ranjan Thakur and Shaon Ray Chaudhuri
  Soluble sulfate contamination in water is observed due to various industrial activities. Chemical means of reduction are available yet the biological approach is the preferred one. Problem statement: The problem addressed in this study was the isolation of efficient sulfate reducing bacterial consortia for bioremediation of soluble sulfate from mining effluent. Approach: The culture based method using the DSMZ specific media were used for isolation of sulfate reducing bacterial consortia. Their reduction efficiency was measured spectrophotometrically following growth under varied temperature and pH in specified media as well as in effluent water. The microbial consortia were analyzed at the 16SrDNA level to identify the members. The completeness as well as richness of the study was analyzed using OTU saturation curve, Shannon diversity index and equitability index. Results: All the eight consortia were able to tolerate vide range of pH (6-9) and temperature (20-40°C). They could reduce 63-99% of soluble sulfate (~2000 ppm) in 48 h. Conclusion: This study reported about the enrichment of few of the most efficient anaerobic microbial consortia that could be employed for environmental soluble sulfate reduction under diverse pH and temperature conditions.
  Shaon Ray Chaudhuri , Ashoke Ranjan Thakur , Poulomi Nandy and Santanu Samanta
  Urinary Tract Infection, commonly known as UTI, affects as many as 50% women at least once during their lifetime. All individuals are susceptible to Urinary Tract Infection (UTI); however the prevalence of infection differs with age, sex and certain predisposing factors. With the above background in mind we conducted a survey of the local population (women of 3 age groups) to compare the urinary tract microbial community of control individuals with the UTI positive patients. Attempts were made to identify pathogens through Serum Bactericidal Antibody Response. 200 urine samples collected from control as well as UTI patients were randomly inoculated in parallel on four varieties of chromogenic agar plates and the Colony Forming Units (CFU) per milliliters (ml) of each microbe was determined. The serum bactericidal antibody assay was performed to demonstrate the presence of serum antibodies with bactericidal activity against the bacterium found in urine. However, with further experimental analysis, this bactericidal activity was found to be non specific and a similar percentage of bacteriolysis was observed incase of the control population also. 104-105 CFU mL-1 was the demarcating value between normal and pathological samples in asymptomatic cases. A significant variation was also noted in the microbial profile of various age groups. E. coli is the most prevalent pathogen in the post menopausal group. 15 different bacterial isolates were obtained of which the 16S rDNA sequence of the 6 novel ones are available in GenBank. The control and patient population showed a clear cut variation in the percentage of urinary tract microbes.
  Jaysankar Sing Yadav , Sanhita Chowdhury and Shaon Ray Chaudhuri
  In an earlier study, we had isolated and identified a protease producing bacterium as Pseudomonas aeruginosa from the Charakdanga Bheri waters of East Calcutta Wetland. The enzyme was concentrated by lyophilization and finally purified by hydrophobic interaction chromatography using Phenyl Sepharose CL-4B column resulting in 1.2 fold increase in specific activity and 28% recovery. The crude extracellular protein was run on a 12% SDS-PAGE; two bands were found, one between 43 and 66 kDa and another between 29 and 43 kDa. The molecular weight of the purified protein was 36.18 kDa as determined from ESI-Mass Spectroscopy; corresponding to the lower band of the crude sample. The zymogram showed a sharp zone of clearance corresponding to the lower band confirming protease activity. The optimum temperature for the protease activity was 40°C. The protease activity showed a wide range of pH tolerance with almost similar activity ranging from pH 5 to 8. The activity of the enzyme was totally lost in the presence of chelating agent EGTA (10 μM), Phosphoramidone (500 μg mL-1) and 1,10 Phenanthroline (2 μM), suggesting the purified enzyme to be a metalloprotease, while other protease inhibitors had no effect on the enzyme activity. Moreover, since phosphoramidone is a metallo-endoprotease inhibitor, this finding was further confirmed. The endoprotease nature was confirmed through BSA digested banding pattern generation. The kinetics of protease activity revealed that BSA was completely digested within 8 to 9 min and a minimum of 5 μL (6 mg mL-1) of crude protease soup was required for digestion of 50 μg BSA solution.
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