Xinxing, China
Xinxing, China

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Luo H.,Sun Yat Sen University | Qin J.,Guangdong Wens Food Co. | Chen F.,South China Agricultural University | Xie Q.,South China Agricultural University | And 3 more authors.
Virus Genes | Year: 2012

As part of our ongoing surveillance program, 40 field strains of avian infectious bronchitis virus (IBV) were isolated from dead or diseased chicken flocks in different areas of China between 2009 and 2010. S1 glycoprotein genes of these strains were sequenced and analyzed with 38 strains published in GenBank. S1 genes of these isolated strains and the vaccine strains showed nucleotide homologies ranging from 65.2 to 82% and amino acid homologies ranging from 58.4 to 81.9%. Meanwhile, Chinese IBV strains isolated in this study, which were mainly nephropathogenic, could be separated into six variant lineages (CH I-CH VI), and current vaccine strains used in China formed Mass variant lineage that is evolutionarily distant from Chinese isolates. Moreover, CK/CH/GD/NC10, CK/CH/GD/KP10, and our previous isolates TC07-2 formed the CH VI lineage, showing larger evolutionary distances from other strains. Taken together, these findings suggested that various variant lineages were co-circulating in China now, and appeared to be continuously evolving, alternative indigenous vaccines indeed need for effective control of IB in China. © Springer Science+Business Media, LLC 2011.

Lin-Guo W.,South China Agricultural University | Chun-Yi X.,Sun Yat Sen University | Hong-Bin L.,Sun Yat Sen University | Xiao-Rong L.,South China Agricultural University | And 4 more authors.
Journal of Animal and Veterinary Advances | Year: 2012

Little is known about the structure and physicochemical properties of the Infectious Laryngotracheitis Virus (ILTV) genome until recently a few years. To date, there is no protocol that is suitable for preparation of pure cell-associated herpesvirus DNA isolates from infected tissues or from tissue culture. The products of traditional methods are often found to be contaminated with host cellular DNA, especially for preparations of the large ILTV DNA genome. In addition, there is a need to develop methods for the isolation of highly purified viral DNA from cell culture or tissue samples to be used for high-throughput nucleotide sequencing. In this study, the isolation of ILTV from Chorioallantoic Membranes (CAM) was chosen as the model to test a method for purification of cell-associated herpesvirus DNA. The protocol was a combination of Triton X-l 00 lysis, nuclease treatment, nuclease denaturation, phenol-chloroform extraction and subsequent selective removal of small DNA fragments. The results showed that the cell background contamination was reduced significantly to a level that was suitable for 454 pyrosequencing and downstream applications such as cloning of viral DNA fragments or transfection of genomic viral DNA. This novel protocol, therefore has several advantages compared with existing methods.

Luo H.,Sun Yat Sen University | Zhu D.,Technical Center | Xue C.,Sun Yat Sen University | Qin J.,Guangdong Wens Food Co. | And 2 more authors.
Journal of Animal and Veterinary Advances | Year: 2012

A highly conserved region of la gene of Infectious Bronchitis Virus (IBV) was chosen to design the Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) degenerate primers. The developed RT-LAMP assay is a highly sensitive, specific, rapid method to detect IBV in allantoid and tissue. Optimal temperature was around 62°C and duration was 45 min. Sensitivity analysis showed that RT-LAMP assay was 10 fold more sensitive than RT-PCR. Specificity analysis showed that 3 IBV strains omitted by the previous reported RT-LAMP assay could be detected by the improved RT-LAMP assay. In field trials, the improved RT-LAMP assay obtained 98.4% sensitivity in 65 clinical samples while 95.4% of RT-PCR and 93.8% of the previous reported RT-LAMP which indicates it is a powerful tool in the practical application. © Medwell Journals, 2012.

Feng K.,South China Agricultural University | Feng K.,Key Laboratory of Chicken Genetics | Xue Y.,Guangdong Wen's Food Co. | Wang F.,Guangdong Wen's Food Co. | And 5 more authors.
Virus Genes | Year: 2014

Sixty-two strains of avian infectious bronchitis virus (IBV) were isolated from diseased chickens at different farms in southern China during 2011–2012, and 66.1 % of the isolated strains were associated with typical nephritis. Analysis of the S1 gene sequences amplified from the 62 isolated strains together with 40 reference strains published in Genbank showed nucleotide homologies ranging from 63.5 to 99.9 % and amino acid homologies ranging from 57.9 to 100 %. Phylogenetic analysis revealed that all Chinese IBV strains were clustered into six distinct genetic groups (I–VI). Most of the isolated strains belonged to group I, and the isolation of group V strains was increased compared with an earlier period of surveillance. Current vaccine strains used in China (H120, H52, W93, and Ma5) formed the group Mass which is evolutionarily distant from Chinese isolates. Alignment of S1 amino acid sequences revealed polymorphic and diverse substitutions, insertions, and deletions, and the S1 protein of major pandemic strains contained 540 amino acids with a cleavage site sequence of HRRRR or RRF(L/S)RR. Further analysis showed that recombination events formed a new subgroup. Taken together, these findings suggest that various IBV variants were co-circulating and undergoing genetic evolution in southern China during the observation period. Therefore, long-term continuing surveillance is significantly important for prevention and control of IBV infection. © 2014, Springer Science+Business Media New York.

PubMed | South China Agricultural University and Guangdong Wens Food Co.
Type: Journal Article | Journal: Journal of veterinary science | Year: 2016

Outbreaks of pseudorabies (PR) have occurred in southern China since late 2011, resulting in significant economic impacts on the swine industry. To identify the cause of PR outbreaks, especially among vaccinated pigs, 11 pseudorabies virus (PRV) field strains were isolated from Guangdong province during 2013-2014. Their major viral genes (gE, TK, gI, PK, gD, 11K, and 28K) were analyzed in this study. Insertions or deletions were observed in gD, gE, gI and PK genes compared with other PRV isolates from all over the world. Furthermore, sequence alignment showed that insertions in gD and gE were unique molecular characteristics of the new prevalent PRV strains in China. Phylogenetic analysis showed that our isolates were clustered in an independent branch together with other strains isolated from China in recent years, and that they showed a closer genetic relationship with earlier isolates from Asia. Our results suggest that these isolates are novel PRV variants with unique molecular signatures.

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