Genome sequence analysis of nsp15 from SARS-CoV-2.

SARS-CoV-2 (Severe Acute Respiratory Syndrome), a causative agent of COVID-19 disease created a pandemic situation worldwide. Nsp15 is a uridine specific endoribonuclease encoded by the genome of SARS-CoV-2. It plays important role in processing viral RNA and, thus evades the host immune system. Therefore, it is of interest to identify mutants of nsp15 amongst Asian SARS-CoV-2 isolates, where a total of 1795 mutations, from 7793 sequences of Asia submitted till 31st January 2022, amongst which A231V, H234Y, K109N, K259R and S261A mutations were found frequent. Hence, we report data on the predicted secondary structure of wild type form followed by hydropathy plot, physiochemical properties, Ramachandran plot, B-cell epitopes prediction and protein modeling of wild type and mutant of nsp15 protein. Data shows that nsp15 of SARS-CoV-2 is a pontential candidate for the development of vaccine to control the infections of SARS-CoV-2.

Risk assessment of low arsenic exposure using biomarkers of oxidative and genotoxic stress in a piscine model.

The high level exposure to arsenic induces marked oxidative and genotoxic stress. However, information on the potential of low level arsenic exposure in this context is still scanty. In the present study, the extent of oxidative stress and genetic toxicity induced by low arsenic exposure was explored in freshwater fish Channa punctatus. Fish were exposed to low levels of arsenic (10 and 50 µg L-1) as well as to its high level (500 µg L-1) using sodium arsenite in aquaria water for 14 consecutive days. The TBARS assay for lipid peroxidation exhibited the increased occurrence of oxidative damage in the erythrocytes of fish at both the lower and higher levels of arsenic exposure. The level of reduced glutathione was also elevated in all the three arsenic exposed groups of fish compared to control. In contrast, significant decline was observed in the levels of three major antioxidant enzymes namely, superoxide dismutase, catalase and glutathione peroxidase, upon exposure to higher as well as lower levels of arsenic. Significant increases in micronucleus induction were found in the erythrocytes of fish even at the low levels of arsenic exposure. The study further revealed the occurrence of DNA fragmentation in the erythrocytes of fish at low arsenic exposures as well. The low level exposure to arsenic (using sodium arsenite), therefore, appeared to be capable of inducing noticeable oxidative stress as well as potential genotoxic effect in Channa punctatus. Moreover, the ability of arsenic to induce oxidative stress invariably appeared correlated with its genotoxic potential.