Assessment of immunization regimens of duck Riemerella anatipestifer vaccines

In Silico Analysis and Immune Response of YaeT Protein Against Riemerella anatipestifer in Ducks

Riemerella anatipestifer (RA) is one of the most harmful bacterial pathogens in waterfowl and causes enormous economic loss worldwide. Due to weak cross-immunity protection against different serotypes of RA, inactivated and attenuated vaccines are only effective for RA of specific serotypes. In this paper, outer membrane protein YaeT in RA was analyzed through bioinformatics, in vivo, and in vitro assays. Homology, physicochemical and structural properties, transmembrane domains, and B-cell binding epitopes were investigated. The recombinant outer membrane protein YaeT was then inoculated into Cherry Valley ducks to analyze its immune protection against RA. Results showed that the protein was conservative in different RA strains and had sufficient B-cell binding epitopes. The immunized duck serum contains high-affinity antibodies that could activate complement and promote the opsonophagocytosis of RA by phagocytes. After RA challenge, the survival rate of the YaeT protein-immunized ducks was 80%.

Faecalibacter bovis sp. nov., isolated from cow faeces

A Gram-stain-negative, non-spore-forming, yellow-pigmented, aerobic, pleomorphic rod-shaped bacterium, designated ZY171143^T, was isolated from faeces of a cow with diarrhoea in Wenshan, Yunnan Province, south-west China and its taxonomic position was studied. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZY171143^T belonged to the family Weeksellaceae and was most closely related to the only species of the genus Faecalibacter, Faecalibacter macacae CCTCC AB 2016016^T with a sequence similarity of 97.8 %. The genomic OrthoANI and digital DNA-DNA hybridization values between the strain and F. macacae CCTCC AB 2016016^T were 86.2 and 30.5 %, respectively. The genomic G+C content was 31.1 mol%. The predominant fatty acids (>5 %) were C_15 : 0 iso, C_17 : 0 iso 3OH, C_16 : 0, C_16 : 1ω5c and summed feature 3 (C_16 : 1ω7c and/or 16 : 1 ω6c). The major polar lipids were phosphatidylethanolamine, triacylglycerol and sulfonolipid. The sole respiratory quinone was MK-6. These chemotaxonomic characterizations also revealed that strain ZY171143^T was a member of the genus Faecalibacter. Based on the phenotypic, chemotaxonomic and genotypic data, strain ZY171143^T represents a novel species within the genus Faecalibacter, for which the name Faecalibacter bovis sp. nov. is proposed. The type strain is ZY171143^T (=CGMCC 1.13663^T=KCTC 62642^T).