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Outbreak of COVID-19 by SARS-CoV-2 infection caused severe acute respiratory syndrome that has been declared a public health emergency of international concern. To control infections, there is urgent need to develop an effective therapeutic strategy. COVID-19 viral spike glycoprotein and proteases play major role in viral entry and mediating virus replication and spread and thus can serve as potential antiviral drug target. Being highly specific, efficacious and safe, peptides hold their place in therapeutics. In present study, molecular docking of 21 pharmacologically active non ribosomal peptides (NRPs) from marine microbes with SARS-CoV-2 spike glycoprotein and papain such as protease was done. Dactinomycin, Tyrocidine A and Gramicidin S showed highest binding interaction with target proteins. The binding affinity of Dactinomycin and Gramicidin S docked with SARS-CoV-2 spike glycoprotein was − 12.4 kcal/mol and − 11.4 kcal/mol, respectively. This suggested their potential to destabilize SARS spike protein binding with human host ACE2 receptor and thus hindering viral entry to the cells. Binding affinity of Tyrocidine A and Gramicidin S with SARS-CoV-2 papain-like protease was − 13.1 kcal/mol and − 11.4 kcal/mol, respectively which might be inhibited COVID-19 by acting on the protease. Gramicidin S showed same binding affinity for both target proteins and thus expected to be most potent. Based on the binding energy score, it was suggested that these pharmacologically active NRPs are potential molecules to be tested against SARS-CoV-2 and used to develop effective antiviral drugs.

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Salmonella enterica serotype typhi is a gram-negative, rod-shaped bacterium, and has flagella with the human body as its only reservoir. Typhoid fever was found to cause 21.7 million illnesses and 216,000 fatalities worldwide in 2000, and the International Vaccine Institute estimated 11.9 million cases and 129,000 deaths in low- and middle-income countries in 2010. More than 10 million patients were infected with S. typhi each year and the mortality rate is associated with more than 0.1 million patients. Moreover, it is also associated with drug resistance globally which makes the disease more dreadful. Other than antibiotics, various flavonoids showed medicinal effects against many diseases including S. typhi infection. Flavonoids are a type of plant bioactive metabolite that have potential medicinal efficacy. The goal of this study was to see if certain flavonoids (ellagic acid, eriodictyol, and naringenin) could interact with the outer membrane of osmoporin (PDB ID: 3uu2) receptor in Salmonella and helps in inhibiting its growth. To look for probable ligand-receptor binding relationships, we used Pyrxmolecular docking software. The molecular docking results were analyzed using the Biovia discovery studio visualizer. The current study discovered that selected plant-based compounds interacted with an outer membrane of the osmoporin receptor, resulting in minimization of energy in the range of-6.6 to -7.8 Kcal/mol.

Lactic acid bacteria (LAB) are economically important because of their fermentative aptitude and also confer health and nutritional bene ts. Pediococcus acidilactici NCDC 252 is potential probiotic with novel genome that exhibited all in-vitro probiotic attributes, colonization in intestine and survival in conditions that mimick gastric, intestinal and vaginal uid. Genome was screened for its ability to produce antimicrobial peptide (AMP). AMP activity was screened by spot on lawn method and by measuring zone of inhibition (ZOI) against indicator strain (E.coli). AMP production was optimized with highest production in MRS broth at 32℃, pH 6 and after 36 h of incubation under both aerobic and anaerobic conditions. AMP was puri ed 2.2 fold with yield of 7.2% and speci c activity of 64.5 U mg/ml by ammonium sulphate precipitation (upto 70%) and gel ltration chromatography. Molecular weight of puri ed AMP was calculated to be 2.5 KDa. Tricine SDS-PAGE and LC/MS studies con rmed it to be a low molecular weight peptide. AMP was stable over pH range of 3 to 9 and temperature range of 40℃ to 100℃. Enzymatic treatment inactivated the AMP whereas, detergent treatment enhanced AMP's activity. Biopreservation potential of puri ed AMP and whole NCDC 252 cells was studied by incubating them with some dairy products, apple juice, apricot pulp and pre-pasteurized wine over 72 h. Bacterial growth in AMP treated food products reduced signi cantly after 72 h. Viable cell count decreased to approximately half in all studied food items in both puri ed AMP treated and NCDC 252 treated food products.