Molecular and Cultures based Diagnosis of Infectious Bursal Disease Virus (IBDV) in Vaccinated and Non Vaccinated Poultry Flocks

Background: In recent years, Infectious bursal disease is continuously occurring even after vaccination in India and requires an inclusive diagnosis. Therefore, the present study was undertaken to diagnose IBD through molecular and culture methods. Methods: One pooled sample, from each of 54 flocks having birds with IBD like symptoms, was collected. History of bird type, age and vaccination was recorded. Samples were subjected to RT-PCR, egg embryo culture and chicken fibroblast cells culture. Result: A total of 49669 out of 517900 (9.59 %) of birds, aging 3-6 weeks, were displaying the signs similar to IBD.In RT-PCR, 21 (38.88%) samples were found positive which belonged to11 (52.38%) vaccinated and 10 (47.62%) unvaccinated flocks.The RT-PCR positive samples were successfully cultivated for the virus through egg embryo and cell culture. The CEF culture was found least sensitive compared to egg embryo culture and RT-PCR.

In Vitro Inhibition of Influenza Virus Using CRISPR/Cas13a in Chicken Cells

Advances in the field of CRISPR/Cas systems are expanding our ability to modulate cellular genomes and transcriptomes precisely and efficiently. Here, we assessed the Cas13a-mediated targeted disruption of RNA in chicken fibroblast DF1 cells. First, we developed a Tol2 transposon vector carrying the Cas13a-msGFP-NLS (pT-Cas13a) transgene, followed by a stable insertion of the Cas13a transgene into the genome of DF1 cells to generate stable DF1-Cas13a cells. To assess the Cas13a-mediated functional knockdown, DF1-Cas13a cells were transfected with the combination of a plasmid encoding DsRed coding sequence (pDsRed) and DsRed-specific crRNA (crRNA-DsRed) or non-specific crRNA (crRNA-NS). Fluorescence-activated cell sorting (FACS) and a microscopy analysis showed reduced levels of DsRed expression in cells transfected with crRNA-DsRed but not in crRNA-NS, confirming a sequence-specific Cas13a mediated mRNA knockdown. Next, we designed four crRNAs (crRNA-IAV) against the PB1, NP and M genes of influenza A virus (IAV) and cloned in tandem to express from a single vector. DF1-Cas13a cells were transfected with plasmids encoding the crRNA-IAV or crRNA-NS, followed by infection with WSN or PR8 IAV. DF1 cells transfected with crRNA-IAV showed reduced levels of viral titers compared to cells transfected with crRNA-NS. These results demonstrate the potential of Cas13a as an antiviral strategy against highly pathogenic strains of IAV in chickens.

chGRP78 is Required for the Activation and Phosphorylation of AKT1 at Serine 478 in Chicken Sells

Background: Chicken serum-mediated proliferation regulates chGRP78 to prevent apoptosis in chicken cells via chGRP78-mediated anti-apoptosis. However, the precise molecular mechanisms underlying the chGRP78-mediated protection against apoptosis remain undefined. In an earlier study, we have shown that chGRP78 is critical for chicken embryo fibroblast (CEF) and DF-1 cell proliferation.Methods: In this experiment, we highlight AKT1 as a key target of GRP78 during apoptosis. We used 2D gel-based proteomics and bioinformatics prediction analysis for our studies. Result: Here, we detected chGRP78 binding sites in AKT1-rgulated proteins. chGRP78 promoted AKT1 activation and chGRP78 silencing decreased AKT1 levels. Taken together, we suggest that the AKT1-mediated signaling pathway plays a critical role in GRP78-stimulated fibroblast survival and anti-apoptosis. Our findings have important implications for the maintenance of chicken fibroblast cells via the inhibition of apoptosis.

Genome Analysis of a Novel Tembusu Virus in Taiwan

We identified and isolated a novel Tembusu virus (TMUV) strain TP1906 (TMUV-TP1906) from a Culex annulus mosquito pool collected from the northern part of Taiwan in 2019. The TMUV-TP1906 genome is a 10,990-nucleotide-long, positive-sense, single-stranded RNA, consisting of a single open reading frame (ORF) encoding a polyprotein of 3425 amino acids, with 5′ and 3′ untranslated regions (UTRs) of 94 and 618 nucleotides, respectively. The nucleotide sequence of the TMUV-TP1906 of ORF exhibited 93.71% and 91.27% similarity with Sitiawan virus (STWV) and the TMUV prototype strain MM1775, respectively. The 3′-UTR variable region of TMUV-TP1906 showed nucleotide sequence divergence with other TMUV strains. Phylogenetic analysis of the complete ORF and polyprotein sequences revealed that TMUV-TP1906 is most closely related to STWV which causes encephalitis and retarded growth in chickens. We found that the TMUV-TP1906 caused a cytopathic effect (CPE) in the DF-1 chicken fibroblast cell line, while no apparent CPE was observed in Vero and C6/36 cells. In this study, we first identified and isolated a novel TMUV strain in Taiwan. In addition, to our knowledge, it is the first time that the TMUV strain was isolated from the Cx. annulus mosquitoes. Further study is warranted to investigate the host range and virulence of TMUV-TP1906.