Development and application of SYBR Green â real-time quantitative reverse transcription PCR assay for detection of swine Getah virus.

Getah virus (GETV), a mosquito-borne virus belonging to the Alphavirus genus of family Togaviridae, has become increasingly problematic, which poses a huge threat to the safety of animals and public health. In order to detect GETV quickly and accurately, we have developed a SYBR Green I real-time quantitative reverse transcription PCR (RT-qPCR) assay for GETV with the detection limit of 66 copies/µL, excellent correlation coefficient (R2) of 0.9975, and amplification efficiency (E) of 98.90%, the target selected was the non-structural protein 3 of GETV. The sensitivity of it was higher than that of ordinary RT-PCR by 1000 folds, and the inter-assay and intra-assay CV values were all less than 0.99%. The newly developed RT-qPCR assay exhibited good sensitivity and reproducibility, which will provide technical support for the reliable and specific rapid diagnosis, and quantitative analysis of GETV infection.

The role of GtxA during Gallibacterium anatis infection of primary chicken oviduct epithelial cells.

Gallibacterium anatis (G. anatis), one of the major pathogens causing reproductive tract disorders in laying hens, leads to a reduction in egg production and increased mortality, caused by either single or mixed infections with other pathogens. As a specific virulence factor of G. anatis, the role of GtxA in layers' salpingitis remains unclear. In this study, we explored the effect of GtxA on G. anatis infection by comparing wild strain Yu-PDS-RZ-1-SLG (RZ) and its GtxA deleted counterpart RZΔgtxA in primary chicken oviduct epithelial cells (COEC). Their adherence, invasion, cytoxicity, and ability to induce apoptosis and and cytokine secretion were evaluated and the cytotoxicity and cytokine secretion of the recombinant GtxA protein and its N-terminal adenylate cyclase and C-terminal RTX hemolysin domain were also analyzed. We found that the adhesion ability of RZΔgtxA was significantly lower than that of parental strain RZ, and its toxicity to COEC was weakened; Meanwhile, apoptosis was inhibited and the expression of IL-6, IL-2, TNF-α and IFN-γ were dramatically reduced in COEC infected by RZΔgtxA. In contrast, the recombinant protein GtxA inhibited the proliferation of oviduct cells and induced obvious cytotoxicity, and the expression of IL-6, TNF-α and IFN-γ were up-regulated in COEC interacted with recombinant proteins. Our study indicates that GtxA promotes G. anatis adherence to cells, changes cells permeability and expression of inflammatory factors, resulting in cell damage and apoptosis.