Biotransformation of chromium by root nodule bacteria Sinorhizobium sp. SAR1.

The present study aims to address the problem of chromium (Cr) toxicity by providing important insights into the mechanisms involved in its bioremediation. Among the 22 Rhizobium and Sinorhizobium isolates obtained from Sesbania sesban root nodules, Sinorhizobium sp. SAR1 (JX174035.1) tolerated the maximum Cr concentration (1mM) and hence was used for further studies. The excess secretion of extra polymeric substances, as seen from scanning electron micrographs, could be a probable mechanism of adaptation to the Cr stress. The Energy dispersive X-ray spectroscopy data did not show any peaks of Cr. The biosorption studies done on the isolate gave maximum adsorption capacity as 285.71mg/g. The isotherm studies showed a better fit to Langmuir isotherm. The Weber and Morris plot established that the phenomenon of adsorption was governed by film diffusion mechanism. The FTIR analysis suggested the role of cell wall components and extracellular polymeric substances in Cr adsorption to the biomass of Sinorhizobium. On the basis of these results a compiled mechanism of Cr (VI) adsorption and its biotransformation into Cr (III) by Sinorhizobium sp. SAR1 is explained. This work outlines a comprehensive detail for the exact phenomenon of Cr biotransformation by Sinorhizobium sp. SAR1. These results may further help in developing and enhancing effective bioremediation approaches.

Characterization of Indian beers: chemical composition and antioxidant potential.

Chemical composition, antioxidant potential and corresponding lipid preoxidation of Indian commercial beers were evaluated. The presence of polyphenolic compounds such as tannic acid, gallic acid, catechol, vanillin, caffeic acid, quercetin, p-coumaric acid and rutin was quantified using LC-MS while the organic acids including tartaric, malic, acetic, citric and succinic acids were analysed using HPLC. Beer sample B8 had the greatest concentration of phenolic and flavonoid components (0.620 ± 0.084 mg/mL and 0.379 ± 0.020 mg/mL respectively) among the beer samples studied. The DPPH radical scavenging activity was observed in the range of 68.34 ± 0.85 % to 89.90 ± 0.71 % and ABTS radical cation scavenging activity was in the range of 59.75 ± 0.20 % to 76.22 ± 0.50 %. Percent protection in lipid peroxidation was quantified to be maximum (54.45 ± 3.39 %) in sample B5. Total phenolic content positively correlates with antioxidant assays, DPPH and ABTS (r = 0.35 and r = 0.58 respectively) with p < 0.001 and also with lipid peroxidation (r = 0.04) with p < 0.001. Negative correlation was observed between total flavonoid content with ABTS and lipid peroxidation (r = -0.1 and r = -0.05) respectively. The process of brewing warrants additional research to determine how the concentration of selected phenolic compounds can be increased.

Association of adipocytokines (leptin, adiponectin TNF-alpha), insulin and proinsulin with diabetes--the Mumbai Obesity Project [MOP].

Asian Indians have a unique phenotype characterized by increased abdominal obesity and visceral fat despite low body mass index [BMI]. Though studies have indicated some adipocytokines to be associated with diabetes and obesity in Indians, there are virtually no studies relating adipocytokines and proinsulin with diabetes and obesity in Asian Indians. In this study we looked at adipocytokines--leptin, adiponectin and tumour necrosis factor-a [TNF-alpha] and insulin and proinsulin in subjects with diabetes and obesity. Thirty five diabetic subjects and 50 healthy controls were recruited for the study. Leptin [p=0.002J and adiponectin levels [p=0.011] were lower and proinsulin values higher [p<0.001] in diabetic subjects compared to non-diabetic subjects. In addition, leptin [p<0.001] and proinsulin [p<0.001] were higher and adiponectin [p<0.001] lower, in obese subjects compared to non-obese subjects. TNF-alpha failed to show any significant difference between the study groups. Leptin and proinsulin showed a significant and positive correlation with BMI [p<0.001] and waist circumference [p<0.001]. Adiponectin showed an inverse correlation with BMI [p=0.050] and waist circumference [p=0.002]. Proinsulin showed a significant negative association with adiponectin [p=0.002]. Logistic regression analysis revealed leptin to be negatively associated [Odds ratio [OR]: 0.864, 95% confidence interval [95% CI]: 0.775 -0.963, p=0.008] and proinsulin [OR: 1.567, 95% CI: 1.246-1.971, p<0.001] to be positively associated with diabetes even after adjusting for age, gender and BMI. Leptin [OR: 1.365, 95% CI: 1.170-1.592, p<0.001] and proinsulin [OR: 1.617, 95% CI: 1.218 -2.147, p=0.001] showed a significant positive association with obesity, while adiponectin [OR: 0.927, 95% CI: 0.865 - 0.995, p=0.035] had a significant inverse association. Linear regression analysis revealed that adiponectin is inversely associated with proinsulin even after the addition of age, gender and diabetes status [beta= -0.61, p=0.033] into the model. In conclusion, in urban Asian Indians in western India, proinsulin levels showed a positive association, while leptin and adiponectin showed a negative association with diabetes. With regard to obesity, leptin and proinsulin had a positive association, while adiponectin had a negative association. Proinsulin levels showed an inverse association with adiponectin indicating a possible link between insulin secretion and insulin resistance.