Japanese encephalitis virus (JEV) is the leading causative agent of encephalitis and its associated mortality among children. JEV modulates host cell machinery for its advantage, such as oxidative damage which subsequently leads to stress responsive pathways. The present study analyzes new series of dinitroaryl substituted derivatives (1a-1f), containing pyrazole moiety and explores its potential ensuing anti-JEV activity. Out of all synthesized derivatives, compounds 1b and 1f were selected based on minimal cytotoxicity. In vitro inhibition of more than 70% and 90% were observed with compounds 1b and 1f, respectively, in neuronal cells. Dose-response analyses highlighted 1f exhibiting better antiviral activity than 1b. The mice treated with compound 1b or 1f did not show any noticeable toxicity at a dose of 100mg/kg/day when administered intraperitoneally till 96th h. Inhibition of up to 41% and 70% JEV mRNA in spleen and 33% to 43% in brain tissue was observed with compounds 1b and 1f, respectively. Both the compounds suppressed JEV induced ROS generation by up-regulating the NQO1 and HO-1 proteins. Our result suggests the interlocked positive feedback loops of NRF2-SQSTM1 signaling pathway to be regulated by the synthesized compounds. The potential of these compounds can be further tested for broad-spectrum antiviral effects with other flaviviruses in the path towards the development of therapeutics.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection presents an immense global health problem. Spike (S) protein of coronavirus is the primary determinant of its entry into the host as it consists of both receptor binding and fusion domain. Besides tissue tropism, and host range, coronavirus pathogenesis are primarily controlled by the interaction of S protein with the cell receptor. Moreover, the proteolytic activation of S protein by host cell proteases plays a decisive role. The host-cell proteases have shown to be involved in the proteolysis of S protein and cleaving it into two functional subunits, S1 and S2, during the maturation process. In the present study, the interaction of the S protein of SARS-CoV-2 with different host proteases like furin, cathepsin B, and plasmin has been analyzed using molecular docking and molecular dynamics (MD) simulation. Incorporation of the furin cleavage site (R-R-A-R) in the S protein of SARS-CoV-2 has been studied by mutating the individual amino acid. MD simulation results suggest the polytropic nature of the S protein. Our analysis indicated that a single amino acid substitution in the polybasic cleavage site of S protein perturb the binding of cellular proteases. This mutation study might help to generate an attenuated SARS-CoV-2. Besides, targeting host proteases by inhibitors may result in a practical approach to stop the cellular spread of SARS-CoV-2 and develop its antiviral.

Newcastle disease is a severe clinical manifestation of avian species caused by Newcastle disease virus (NDV). Although several vaccination strategies are available to protect poultry against NDV infection, even then, outbreaks have been reported in the vaccinated birds. The lack of therapeutics against NDV makes the need for effective anti-viral drugs is of utmost importance. Lithium Chloride (LiCl) is a widely prescribed drug for the treatment of bipolar disorder, acute brain injuries, and chronic neurodegenerative diseases. Also, LiCl has been repurposed as an effective anti-viral drug for some viral infections. In the present work, we have investigated the efficacy of LiCl to inhibit NDV replication using in vitro, in ovo, and in vivo models. Our results collectively showed the modulation of NDV replication after the LiCl treatment. We also demonstrated that NDV induces endoplasmic reticulum stress (ER-stress), and a stress-inducible ER chaperone, glucose-regulating protein 78 (GRP78), was found to be over-expressed after NDV infection. Subsequently, the treatment of NDV infected cells with LiCl significantly reduced the transcript and protein levels of GRP78. Finally, we concluded that LiCl treatment protects the cells from ER-stress induced by the NDV infection.

Complete consensus genome sequences were determined for avian paramyxovirus type 8 (APMV-8) strains goose/Delaware/1053/76 (prototype strain) and pintail/Wakuya/20/78. The genome of each strain is 15,342 nucleotides (nt) long, which follows the "rule of six". The genome consists of six genes in the order of 3'-N-P/V/W-M-F-HN-L-5'. The genes are flanked on either side by conserved transcription start and stop signals, and have intergenic regions ranging from 1 to 30nt. The genome contains a 55nt leader region at the 3'-end and a 171nt trailer region at the 5'-end. Comparison of sequences of strains Delaware and Wakuya showed nucleotide identity of 96.8% at the genome level and amino acid identities of 99.3%, 96.5%, 98.6%, 99.4%, 98.6% and 99.1% for the predicted N, P, M, F, HN and L proteins, respectively. Both strains grew in embryonated chicken eggs and in primary chicken embryo kidney cells, and 293T cells. Both strains contained only a single basic residue at the cleavage activation site of the F protein and their efficiency of replication in vitro depended on and was augmented by, the presence of exogenous protease in most cell lines. Sequence alignment and phylogenic analysis of the predicted amino acid sequence of APMV-8 strain Delaware proteins with the cognate proteins of other available APMV serotypes showed that APMV-8 is more closely related to APMV-2 and -6 than to APMV-1, -3 and -4.

The complete consensus genome sequence was determined for avian paramyxovirus (APMV) serotype 3 strain Wisconsin. The genome is 16,182 nucleotides (nt) in length, consisting of six non-overlapping genes in the order of 3'-N-P/V/W-M-F-HN-L-5', with a 55-nt leader at its 3' end and a 681-nt trailer at its 5' end. Comparison of the APMV-3 strain Wisconsin nt and the aggregate predicted amino acid (aa) sequences with those of APMV-3 strain Netherlands revealed 67% and 78%, identity, respectively. The nt and aa sequence identities between the two APMV-3 strains were lower than between the two antigenic subgroups of human respiratory syncytial virus (81% and 88% identity, respectively) and the two subgroups of human metapeumovirus (80% and 90% identity, respectively). Reciprocal cross-hemagglutination inhibition and cross-neutralization assays using post-infection sera from chickens indicated that strains Wisconsin and Netherlands are highly related antigenically, with only a 2- to 4-fold difference in antibody reactivity between the homologous and heterologous strains. Taken together, our results indicate that the two APMV-3 strains represent a single serotype with two subgroups that differ substantially based on nt and aa sequences, but with only a modest antigenic difference.

The complete genome sequence was determined for prototype parakeet/Netherlands/449/75 strain of avian paramyxovirus (APMV) serotype 3. The genome is 16,272 nucleotides (nt) in length, consisting of six non-overlapping genes in the order of 3'-N-P/V/W-M-F-HN-L-5', with intergenic regions of 31-63nt. APMV-3 genome follows the "rule of six" and is the largest among the avian paramyxoviruses reported to date, with a trailer region of 707nt, the longest in the family Paramyxoviridae. The cleavage site of F protein, A-R-P-R-G-R downward arrowL, does not conform to the preferred cleavage site of the ubiquitous cellular protease furin. Therefore, exogenous protease was needed for replication in vitro. Alignment and phylogenetic analysis of the predicted amino acid sequences of strain Netherlands proteins with the cognate proteins of viruses of all of the five genera of family Paramyxoviridae showed that APMV-3 strain Netherlands is more closely related to APMV-1 than APMV-6.

Cholesterol is an essential constituent of the cell membrane that modulates several physiological events, including virus entry into the host. Duck virus enteritis (DVE) is a contagious and lethal infection that attacks several species of waterfowl. Anatid herpesvirus 1 (AnHV-1) is the causative agent of duck viral enteritis and classified under subfamily Alphaherpesvirinae. In this study, the effect of cholesterol depletion in both host cell membrane and viral envelope on the infectivity of AnHV-1 was explored. Cholesterol depletion of chicken embryo fibroblast cells (DF-1) by methyl-β-cyclodextrin (MβCD) inhibited the infectivity of AnHV-1. This inhibitory effect was moderately reversed by the exogenous replenishment of cholesterol in the cells. Furthermore, the inhibition of endogenous cholesterol synthesis by a statin drug also inhibited the infectivity of AnHV-1. Presumably, the removal of cholesterol from AnHV-1 envelope might be disrupting the viral envelope resulting in its diminished infectivity. The presence of a relatively hydrophobic cavity in MβCD can be used to extract cholesterol from the cell membrane. Loss of infectivity of the virus might be due to the effects of MβCD mediated cholesterol depletion from the cell membrane. The results implicate that the cell membrane cholesterol is vital for the infectivity of AnHV-1 in DF-1 cells, and its depletion from virion curtails the infectivity by destabilizing the envelope.

Psittacine beak and feather disease (PBFD), caused by beak and feather disease virus (BFDV) is a highly contagious disease in wild and captive psittacine populations and has an almost global presence. However, the BFDV infection in Saudi Arabia remains largely unknown. In the present study, we report the full genome sequence of BFDV strains from Saudi Arabia and its genetic diversity. The complete genome sequences were analyzed for 14 BFDV-infected birds representing 6 psittacine species. The complete genome sequence of BFDV strains was compared with 201 previously reported sequences to evaluate their diversity and possible recombination events, if any. Our analysis revealed that newly sequenced BFDV genomes from Saudi Arabia belonged to six different strains. Phylogenetic analysis suggested that the isolated BFDV genomes were highly recombinant with a high degree of diversity. It is evident from the study that psittacine species in Saudi Arabia are at risk from the spread of BFDV. As per the CITES trade database, about 190,000 parrots have been imported to Saudi Arabia since 1975 over a thousand instances. Presumably, during any of these trade events or unregulated trade of birds has predisposed the introduction of BFDV to Saudi Arabia. Understanding the epidemiology of BFDV is necessitated to address the threat posed by the virus to the psittacine population of Saudi Arabia.