Structural and functional characterization of avian influenza H9N2 virus neuraminidase with a combination of five novel mutations.

The influenza virus neuraminidase (NA) protein is responsible for actively cleaving the sialic acid (SA) bound to the viral hemagglutinin. In the present study, we identified a combination of five novel amino acid substitutions in the NA, conferring increased substrate binding and altered surface characteristics to a low pathogenic avian influenza (LPAI) H9N2 virus strain. The H9N2 strain reported from India, A/Environmental/India/1726265/2017 (H9N2-1726265) showed the combination of amino acid substitutions T149I, R249W, G346A, W403R and G435R, which were in the vicinity of the enzyme active site cavity. The strain A/chicken/India/99321/2009 (H9N2-99321) did not show these substitutions and was used for comparison. Virus elution was studied using turkey red blood cells (tRBCs). NA enzyme kinetics assays were carried out using the MUNANA substrate, which is an SA analogue. Homology modelling and molecular docking were performed to determine alterations in the surface characteristics and substrate binding. H9N2-1726265 showed enhanced elution from tRBCs. Enzyme kinetics revealed a lower KM of H9N2-1726265 (111.5 µM) as compared to H9N2-99321 (135.2 µM), indicating higher substrate binding affinity of H9N2-1726265, due to which the NA enzyme cleaved the SA more efficiently, leading to faster elution. Molecular docking revealed a greater number of binding interactions of H9N2-1726265 to SA as compared to H9N2-99321 corroborating the greater substrate binding affinity. Changes in the surface charge, hydrophobicity, and contour, were observed in H9N2-1726265 NA due to the five substitutions. Thus, the novel combination of five amino acids near the sialic acid binding site of NA, resulted in altered surface characteristics, higher substrate binding affinity, and virus elution.

Cyclophilin A: a possible host modulator in Chandipura virus infection.

Chandipura virus (CHPV), belonging to the genus Vesiculovirus of the family Rhabdoviridae, has been identified as one of the causes of pediatric encephalitis in India. Currently, neither vaccines nor therapeutic drugs are available against this agent. Considering that the disease progresses very fast with a high mortality rate, working towards the development of potential therapeutics against it will have a public health impact. Although the use of viral inhibitors as antiviral agents is the most common way to curb virus replication, the mutation-prone nature of viruses results in the development of resistance to antiviral agents. The recent development of proteomic platforms for analysis of purified viral agents has allowed certain upregulated host proteins that are involved in the morphogenesis and replication of viruses to be identified. Thus, the alternative approach of inhibition of host proteins involved in the regulation of virus replication could be explored for their therapeutic effectiveness. In the current study, we have evaluated the effect of inhibition of cyclophilin A (CypA), an immunophilin with peptidyl-prolyl cis/trans-isomerase activity, on the replication of CHPV. Treatment with cyclosporin A, used in vitro for the inhibition of CypA, resulted in a 3-log reduction in CHPV titer and an undetectable level of CypA in comparison to an untreated control. An in silico analysis of the interaction of the CHPV nucleoprotein with the human CypA protein showed stable interaction in molecular docking and molecular dynamics simulations. Overall, the results of this study suggest a possible role of CypA in facilitating CHPV replication, thus making it one of the potential host factors to be explored in future antiviral studies.

MPdb: Melghat Plant databank.

Melghat Plant databank (MPdb) is the first attempt to review all the past floristic documents and medicinal plants and digitize the Melghat Flora. This curated database contains compiled information about 1028 plants from 139 plant families and 537 genera. Curated medicinal plant information gathered 660 medicinal species records from 128 plant families and 421 genera in MPdb for Melghat Flora. Each plant record is reviewed, scrutinizes, and recorded. More than 9000 records for medicinal uses for nearly 140 diseases, reported phytochemicals, and published cross references. MPdb will serve as a valuable information resource for students, researchers, and aboriginal communities to explore Melghat Flora for better-applied prospects in herbal drug research.

Epidemiological findings for the first and second waves of COVID-19 pandemic in Maharashtra, India.

India is one of the worst affected countries during the COVID-19 pandemic. We carried out comparative analyses of the COVID-19 situation in the Maharashtra state, India for the first and second waves. Epidemiological and demographics data were obtained from open sources and the Government of Maharashtra. Mathematical modeling and analyses were conducted to estimate the epidemiological parameters like basic reproduction number (R0) for the first wave at different times. The districts with a higher percentage of the urban population recorded a higher attack rate during the first wave. However, during the second wave, the rural population was more affected. The effective reproduction number (Re) was estimated for the second wave at different times. The second wave affected more individuals than the first wave due to various factors such as strictness of restrictions or the lack of it and the emergence of new strains.

Design of a multi-epitope peptide vaccine candidate against chandipura virus: an immuno-informatics study.

Chandipura virus (CHPV) is an emerging pathogen responsible for acute encephalitic syndrome (AES) in pediatric population in India. Several outbreaks of CHPV have been reported from different states of India since the year 2003. At present there is no vaccine or therapeutic measures available to curtail the disease. In this study, we have identified both T-cell and B-cell epitopes of different antigenic proteins of CHPV like Nucleoprotein (N), Phosphoprotein (P) and Matrix protein (M) along with the immuno-dominant glycoprotein (G) and conducted in silico characterization for the same. The idea is to design a multi-epitope peptide construct using the epitopes, which were found to be non-toxic, non-allergenic and possessing high immunogenicity. The final multi-epitope construct named as: MEC-CHPV, comprised of ß-defensin adjuvant at N-terminal for enhancement of immunogenicity followed by fourteen B-cell epitopes, four Helper T-cell epitopes and six Cytotoxic T-cell epitopes. The characterization of designed construct was carried out in terms of physicochemical parameters, antigenicity and allergenicity. The 3D structure prediction was performed. Molecular docking and molecular-dynamics simulation of MEC-CHPV with Toll like receptors (TLR-3 and TLR-8) showed stable interactions. In silico cloning of MEC-CHPV in pET30a(+) expression vector was also conducted using codon optimization. The in silico immune-simulation indicated a typical immune response against MEC-CHPV when used as a potential vaccine. This study provides a cost-effective and time-saving way to design a peptide vaccine candidate against CHPV using immuno-informatics approach. Development of the MEC-CHPV construct may pave the way for future laboratory experiments.Communicated by Ramaswamy H. Sarma.