The COVID-19 pandemic caused unprecedented damage to humanity, and while vaccines have been developed, they are not fully effective against the SARS-CoV-2 virus. Limited targeted drugs, such as Remdesivir and Paxlovid, are available against the virus. Hence, there is an urgent need to explore and develop new drugs to combat COVID-19. This study focuses on exploring microbial natural products from soil-isolated bacteria Streptomyces sp. strain 196 and RI.24 as a potential source of new targeted drugs against SARS-CoV-2. Molecular docking studies were performed on holoRdRp and nsp13, two key factors responsible for virus replication factor. Our in silico studies, K-252-C aglycone indolocarbazole alkaloid (K252C) and daunorubicin were found to have better binding affinities than the respective control drugs, with K252C exhibiting binding energy of - 9.1 kcal/mol with holoRdRp and - 9.2 kcal/mol with nsp13, and daunorubicin showing binding energy at - 8.1 kcal/mol with holoRdRp and - 9.3 kcal/mol with nsp13. ADMET analysis, MD simulation, and MM/GBSA studies indicated that K252C and daunorubicin have the potential to be developed as targeted drugs against SARS-CoV-2. The study concludes that K252C and daunorubicin are potential lead compounds that might suppress the inhibition of SARS-CoV-2 replication among the tested microbial compounds and could be developed as targeted drugs against COVID-19. In the future, further in vitro studies are required to validate these findings. [GRAPHICS]

The SARS-CoV-2 pandemic resulted in India imposing a nationwide lockdown on 22 March 2020, bringing all human activities to a complete halt. The current study focuses on the effect of lockdown on the abundance of atmospheric aerosols over Goa. The study focused on pre-lockdown, lockdown and period corresponding to lockdown in 2019. The AOD spectra depicted a decrease in the anthropogenically derived fine mode aerosols during the lockdown compared to the pre-lockdown period. Mean AOD(500) for prelockdown and lockdown periods were 0.43 +/- 0.19 and 0.53 +/- 0.11 respectively. The higher AOD(500) during lockdown was due to an increase in naturally derived coarse mode aerosols, which is further confirmed with the lower Angstrom exponent values (1.04 +/- 0.11). The mean black carbon mass concentration for the respective periods were 1990.45 +/- 470.87 ng m(-3), and 1109.71 +/- 218.33 ng m(-3), and the mean atmospheric forcing during the respective periods were 25.13 +/- 5.72 W m(-2), 27.31 +/- 3.71 W m(-2) and 30.81 +/- 5.59 W m(-2) respectively.