Identification of an H1N1 subtype of swine influenza virus and serological analysis

To investigate the epizootic of swine influenza virus(SIV),60 nasal swabs were collected from a clinical cases of pig farm in Tai’an City,Shandong Province of China in April 2017.SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced.An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1).Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch,seven genome segments belonged to avian-like H1N1 influenza virus lineage.The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G,which is a typical molecular biological characteristic.Five potential N-glycosylation sites(N14,N26,N277,N484 and N543) were found in the HA gene.To further investigate the epidemiology of SIV in this farm,the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens.The results showed that the total positive rate was 65.43%.The positive rates of single virus infection detected by EAH1N1,2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35,30.85 and 7.47%,respectively.The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm.These data provide evidence of an epizootic of SIV.

High expression level of soluble SARS spike protein mediated by adenovirus in HEK293 cells

AIM： To develop a highly efficacious method for preparation of soluble SAPS S-protein using adenovirus vector to meet the requirement for S-protein investigation. METHODS： The human adenovirus vector was used to express the soluble S-protein （corresponding to 1-1190 amino acids） fused with Myc/His tag using codon-optimized gene construct in HEK239 cells. The recombinant adenovirus bearing S-protein gene was generated by ligation method. The expressed S-protein with Myc/His tag was purified from culture medium with Ni-NTA agarose beads followed by dialysis. The S-protein was detected by Western blot and its biologic activity was analyzed by binding to Vero cells. RESULTS： Under the conditions of infection dose （MOI of 50） and expression time （48 h）, the high-level expression of S-protein was obtained. The expression level was determined to be approximately 75 μg/106 cells after purification. Purified soluble S-protein was readily detected by Western blot with anti-Myc antibody and showed the ability to bind to surface of Vero cells, demonstrating that the soluble S-protein could remain the biologic activity in the native molecule. CONCLUSION： The high-level expression of S-protein in HEK293 cells mediated by adenovirus can be achieved under the optimized expression conditions. The proteins possess the biologic activity, which lays a foundation for further investigation of S-protein biological function.

Gut microbiota-derived short chain fatty acids are potential mediators in gut inflammation

Gut inflammation is a challenging concern in humans and animals,which disturbs normal growth and leads to severe bowel diseases.Short chain fatty acids(SCFA)are the gut microbiota metabolites produced from fermentation of non-digestible carbohydrates,and have been reported to modulate gut inflammation.SCFA have been implicated as the potential therapeutic bioactive molecules for gut inflammatory diseases,and could be an alternative to antibiotic growth promoters(AGP).In this review,the existing knowledge about the types of SCFA,the related gut microbes producing SCFA,the roles of SCFA in maintaining gut homeostasis,and how SCFA modulate gut inflammation is summarized.The therapeutic application of SCFA in the treatment of inflammatory bowel disease(IBD)is also highlighted