Effect of temperature changes on antioxidant enzymes and oxidative stress in gastropod Nerita oryzarum collected along India's first Tarapur Atomic Power Plant site

Temperature can be considered as pro-oxidant factor that favor the generation of ROS on the species with lower antioxidant efficiency may leads to affect the level of tolerance. So the basic antioxidant enzyme activity (LPO, CAT, SOD, GPx and GST) of gastropod Nerita oryzarum was evaluated at six stations which located between the thermal effluent discharges points from Tarapur Atomic Power Station, India. The antioxidant enzyme activity was shown that all enzyme at discharge point (SII station) where the maximum temperature of heated effluent released. The average maximum values of enzyme activity recorded for LPO, CAT, SOD, GPx and GST were 1.88 ± 0.12, 1.52 ± 0.14, 22.57 ± 0.89, 1.98 ± 0.2 and 17.22 ± 0.63 respectively. The results were inferred the level water temperature directly proportional to the oxidative stress by ROS generation in Nerita oryzarum. Similar results were observed at laboratory experiment under the condition i.e., Treatment 1 (30⁰C), Treatment 2 (35⁰C), Treatment 3 (40⁰C) and Control (25⁰C). The present prima facie work clearly indicated the physiological response of N. oryzarum with respect to antioxidant enzyme activity against the heated effluent released, which will be useful as baseline information for future research work.

Characterization of novel thorium tolerant Ochrobactrum intermedium AM7 in consort with assessing its EPS-Thorium binding

Currently, radioactive waste is disposed primarily by burial in a deep geological repository. Microorganisms thriving in such contaminated environment show tolerance to radionuclides. In the present study the bacterial flora, from soil sample collected from an area around atomic power station exposed to radionuclides and heavy metals, was cultivated and assessed for thorium (Th) tolerance. Of all the isolates, strain AM7 identified as O. intermedium was selected since it could thrive at high levels of Th (1000 mg L^-1). AM7 was characterized physico-chemically and its culture medium was optimized using central composite design of response surface methodology for assessing its growth properties in presence of Th. The strain also showed exceptional exopolysaccharide (EPS) production and its yield was further analyzed using one factor study to investigate the influence of each medium component. On supplementing the EPS medium with Th, no significant decrease in yield was observed. FTIR spectroscopy revealed the functional groups of EPS involved in EPS-Th binding. To the best of our knowledge, this is the first report showing exceptional Th-tolerance by any bacteria. Such study will help other researchers to strategize an environment-friendly way of radwaste disposal.