Significance and impact of the study: Phages are being progressively used as an alternative treatment for antibiotic-resistant bacteria. This report presents a new phage cocktail against MDR strains of Shigella species in aquatic environments. The cocktail was highly efficient in a sense that all of the tested Shigella isolates were infected by at least three of the phages at a high efficiency of plating. The cocktail remarkably decreased Shigella viable count by 99% in an aquatic environment.

Goose astrovirus (GoAstV) is a novel avastrovirus that typically causes gosling gout and results in 2 to 20% mortality. GoAstV capsid protein is the sole structural protein, which is responsible for viral attachment, assembly, maturation as well as eliciting host antibodies. However, the epitopes within capsid protein have not been well studied. In this study, a monoclonal antibody, named 1D7, was generated against GoAstV capsid protein by hybridoma technology. Western blot results showed that this MAb could react with recombinant capsid protein expressed in E. coli. Also, it recognized the precursor of capsid protein, VP90 and VP70, in GoAstV-infected cells. Besides, excellent specificity of MAb 1D7 was further demonstrated in indirect immunofluorescence assay and immunohistochemical analysis. Epitope mapping results revealed that MAb 1D7 recognized the epitope 33 QKVY 36 within Cap protein. Sequence alignment indicated that 33 QKVY 36 is a conserved epitope among the isolates of goose astrovirus type 2 (GoAstV-2), suggesting the potential for its use in GoAstV-2 specific diagnostic assay. These findings may provide some insight into a function of the GoAstV capsid protein and further contribute to the development of diagnostic methods for GoAstV infection.

Bacteriophages (phages) are viruses of bacteria. Despite the growing progress in research on phage interactions with eukaryotic cells, our understanding of the roles of phages and their potential implications remains incomplete. The objective of this study was to investigate the effects of the Staphylococcus aureus phage vB_SauM_JS25 on murine norovirus (MNV) replication. Experiments were performed using the RAW 264.7 cell line. After phage treatment, MNV multiplication was significantly inhibited, as indicated by real-time quantitative PCR (RT-qPCR) analysis, western blot, and immunofluorescence assay. Furthermore, we demonstrated the transcriptional changes in phage-MNV co-incubated RAW 264.7 cells through RNA sequencing (RNA-Seq) and bioinformatic analysis. Our subsequent analyses revealed that the innate immune response may play an important role in the restriction of MNV replication, such as the cellular response to IFN-γ and response to IFN-γ. In addition, the gene expression of IL-10, Arg-1, Ccl22, GBP2, GBP3, GBP5, and GBP7 was proven to increase significantly by RT-qPCR, showing a strong correlation between RT-qPCR and RNA-Seq results. Furthermore, phage treatment activated guanylate binding proteins (GBPs), as revealed by RT-qPCR analysis, western blotting, and confocal microscopy. Taken together, these data suggest that the phage affects the innate response (such as the IFN-inducible GTPases and GBPs), reflecting their direct antimicrobial effect on the membrane structure of the MNV replication complexes, and therefore, exerts an antiviral effect in vitro. Collectively, our findings provide insights into the interactions of immune cells and phages, which improve our understanding of the actual role and potential of phages.