Proteomic analysis of host cellular proteins co-immunoprecipitated with duck enteritis virus gC

Dissecting Selective Signatures and Candidate Genes in Grandparent Lines Subject to High Selection Pressure for Broiler Production and in a Local Russian Chicken Breed of Ushanka

Breeding improvements and quantitative trait genetics are essential to the advancement of broiler production. The impact of artificial selection on genomic architecture and the genetic markers sought remains a key area of research. Here, we used whole-genome resequencing data to analyze the genomic architecture, diversity, and selective sweeps in Cornish White (CRW) and Plymouth Rock White (PRW) transboundary breeds selected for meat production and, comparatively, in an aboriginal Russian breed of Ushanka (USH). Reads were aligned to the reference genome bGalGal1.mat.broiler.GRCg7b and filtered to remove PCR duplicates and low-quality reads using BWA-MEM2 and bcftools software; 12,563,892 SNPs were produced for subsequent analyses. Compared to CRW and PRW, USH had a lower diversity and a higher genetic distinctiveness. Selective sweep regions and corresponding candidate genes were examined based on ZFST, hapFLK, and ROH assessment procedures. Twenty-seven prioritized chicken genes and the functional projection from human homologs suggest their importance for selection signals in the studied breeds. These genes have a functional relationship with such trait categories as body weight, muscles, fat metabolism and deposition, reproduction, etc., mainly aligned with the QTLs in the sweep regions. This information is pivotal for further executing genomic selection to enhance phenotypic traits.

Pathogenicity and transmissibility studies on live attenuated duck enteritis virus vaccine in non-target species

In the second half of 2021, a highly pathogenic case occurred in a mixed chicken and duck family farm in Guangdong, China. After the duck flocks were immunized with live attenuated duck enteritis virus vaccine (live attenuated DEV vaccine), the chickens of the same farm showed clinical symptoms similar to duck enteritis, such as pericardial effusion, hepatic hemorrhagic spots, kidney enlargement, and intestinal bleeding, with mass mortality. The infection model of target animal tested, as well as the non-target species, was established according to the risk of live attenuated DEV vaccine and transmission in chickens. Live attenuated DEV vaccine was initially replicated in host animals, released the virus, and effectively colonized in the common environment, according to birds challenged experiments. There was evidence to suggest the mode of transmission of duck enteritis virus, and horizontal transmission is the main route of DEV transmission. In addition, high levels of virus titer were detected in chicken embryos and different tissues of SPF chickens. Different degrees of pathological damage occurred in the tissue of chickens. After the SPF chickens were inoculated with live attenuated DEV vaccine, different degrees of virulence were exhibited, pointing to a potential risk to other domestic bird species.

Evaluation of safety and immunogenicity of duck-plague virus gC/gE double gene deletion

Duck plague caused by duck plague virus (DPV) is a highly contagious disease that can cause serious morbidity and death in waterfowl such as ducks and geese, and bring huge economic losses to the duck industry. In this study, on the basis of the duck plague virus gC gene deletion strain CHv-ΔgC, based on the duck plague virus bacterial artificial chromosome (BAC) platform in our laboratory, the gE gene was knocked out using the traceless deletion technology to obtain gC/gE double gene deletion candidate vaccine strain CHv-ΔgC/gE. The double gene deletion strain (CHv-ΔgC/gE) constructed in this study has greatly weakened virulence, no pathogenicity to ducks, and stable genetic characteristics in vitro and in vivo. Ducks immunized with CHv-ΔgC/gE can produce neutralizing antibodies and ELISA antibody levels comparable to those of commercial duck plague attenuated vaccine immunization, and can resist 100 LD₅₀ CHv challenge of ducks, with good immune protection effect. It has the potential to be further developed into duck plague gC/gE double gene deletion, marked attenuated vaccine.

Functional differentiation of two lhx8 paralogs and possible regulatory role of lhx8a in Japanese flounder (Paralichthys olivaceus)

Lhx8, belonging to the LIM-Homebox family, is involved in the tooth, nervous system, and primordial follicles development in mammals. However, little is known about the regulatory roles of lhx8 in teleosts. In this study, two lhx8 duplicates were identified in Paralichthys olivaceus, termed Polhx8a and Polhx8b, respectively. Bioinformatic analysis showed that Polhx8a was more likely to be a teleost-specific paralog. According to expression analysis, Polhx8a transcripts were almost exclusively concentrated in the oocytes, while Polhx8b was weakly expressed in the spleen, gill, and some facial organs, indicating sub-functionalization of this gene pair during evolution. Furthermore, Polhx8a mRNA level elevated from perinucleolar oocyte (PNO) stage to vitellogenic oocyte (VO) stage transition and changed after exogenous hormone stimulation, proving that Polhx8a was involved in the oocyte development and could be regulated by sex hormones. Yeast two-hybrid, bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (co-IP) experiments captured the positive protein interactions between PoLhx8a and the other two oocyte-specific transcription factors: PoFigla and PoNobox. After knocking down lhx8a in embryos or adult ovaries in vivo, the expression of oocyte-associated genes was significantly down-regulated (P < 0.05). Our findings suggest the evolution and functional differentiation of lhx8 genes, and shed light on the potential role of lhx8a in protein interactions and gene regulation in teleosts.