In Escherichia coli, the canonical intrinsic terminator of transcription includes a palindrome followed by a U-trail on the transcript. The apparent underrepresentation of such terminators in eubacterial genomes led us to develop a rapid and accurate algorithm, GeSTer, to predict putative intrinsic terminators. Now, we have analyzed 378 genome sequences with an improved version of GeSTer. Our results indicate that the canonical E. coli type terminators are not overwhelmingly abundant in eubacteria. The atypical structures, having stem-loop structures but lacking 'U' trail, occur downstream of genes in all the analyzed genomes but different phyla show conserved preference for different types of terminators. This propensity correlates with genomic GC content and presence of the factor, Rho. 60-70% of identified terminators in all the genomes show "optimized" stem-length and DeltaG. These results provide evidence that eubacteria extensively rely on the mechanism of intrinsic termination, with a considerable divergence in their structure, positioning and prevalence. The software and detailed results for individual genomes are freely available on request.

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Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) declared as a pandemic by WHO that has affected more than 40 lakh peoples and caused death of more than 2 lakh individuals across the globe. Limited availability of genomic information of SARS-CoV-2 and non-availability of vaccines and effective drugs are major problems responsible for the ineffective control and management of this pandemic. Several attempts have been made to explore repurposing existing drugs known for their anti-viral activities, and test the traditional herbal medicines known for their health benefiting and immune boosting activity against SARS-CoV-2.In this study, efforts were made to examine the potential of 721 phytochemicals of 37 plant species in inhibiting major protein targets namely, spike glycoprotein, main protease (MPro), NSP3, NSP9, NSP15, NSP10-NSP16 and RNA dependent RNA polymerase of SARS-CoV-2 through virtual screening approach. Results of our experiments revealed that SARS-CoV-2 MPro shared significant dissimilarities against SARS-CoVMPro and MERS-CoVMPro indicating the need for discovering novel drugs. This study has identified the phytochemical cyanin (Zingiber officinale) exhibiting broad spectrum inhibitory activity against main proteases of all the three Coronaviruses. Amentoflavone, agathisflavone, catechin-7-o-gallate and chlorogeninwere shown to exhibit multi target inhibitory activity. This study has identified Mangifera indica, Anacardium occidentale, Vitex negundo, Solanum nigrum, Pedalium murex, Terminalia chebula, Azadirachta indica, Cissus quadrangularis, Clerodendrum serratum and Ocimum basilicum as potential sources of phytochemicals combating nCOVID-19. More interestingly, this study has generated evidences for the anti-viral properties of the traditional herbal formulation “Kabasura kudineer” recommended by AYUSH, a unit of Government of India. Testing of short listed phytochemicals through clinical trials will help in developing effective formulation for management of this pandemic disease. Genomic analysis of identified herbal plants will help in unravelling molecular complexity of therapeutic and anti-viral properties and will pave way for designing synthetic drugs.

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Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) being a causative agent for global pandemic disease nCOVID’19, has acquired much scientific attention for the development of effective vaccines and drugs. Several attempts have been made to explore repurposing existing drugs known for their anti-viral activities, and test the traditional herbal medicines known for their health benefiting and immune-boosting activity against SARS-CoV-2. In this study, efforts were made to examine the potential of 605 phytochemicals from 37 plant species (of which 14 plants were endemic to India) and 139 antiviral molecules (Pubchem and Drug bank) in inhibiting SARS-CoV-2 multiple protein targets through a virtual screening approach. Results of our experiments revealed that SARS-CoV-2 MPro shared significant disimilarities against SARS-CoV MPro and MERS-CoV MPro indicating the need for discovering novel drugs. This study has screened the phytochemical cyanin (Zingiber officinale) which may exhibit broad-spectrum inhibitory activity against main proteases of SARS-CoV-2, SARS-CoV and MERS-CoV with binding energies of (−) 8.3 kcal/mol (−) 8.2 kcal/mol and (−) 7.7 kcal/mol respectively. Amentoflavone, agathisflavone, catechin-7-o-gallate and chlorogenin were shown to exhibit multi-target inhibitory activity. Further, Mangifera indica, Anacardium occidentale, Vitex negundo, Solanum nigrum, Pedalium murex, Terminalia chebula, Azadirachta indica, Cissus quadrangularis, Clerodendrum serratum and Ocimum basilicumaree reported as potential sources of phytochemicals for combating nCOVID’19. More interestingly, this study has highlighted the anti-viral properties of the traditional herbal formulation “Kabasura kudineer” recommended by AYUSH, a unit of Government of India. Short listed phytochemicals could be used as leads for future drug design and development. Genomic analysis of identified herbal plants will help in unraveling molecular complexity of therapeutic and anti-viral properties which proffer lot of chance in the pharmaceutical field for researchers to scout new drugs in drug discovery.