Isolation and phylogenetic analysis of a new Porcine parvovirus strain GD2013 in China.

Porcine parvovirus (PPV), a causative agent of an infectious reproductive disorder causing stillbirth, mummification, embryonic death and infertility (SMEDI) syndrome in swine, is a threat to both domestic pigs and wild boars regardless of age and gender. Recent studies found that the observed average substitution rate in the PPV genome was close to those of the RNA viruses and new strains showing serological neutralization activities different from that of the vaccine strain NADL-2 have been reported. These observations have increased the need for the development of new commercial vaccine strains. In this study, a new PPV strain, GD2013, was isolated from Guangdong, China, and its entire genome sequenced. A phylogenetic tree based on the complete coding region of the genomes of 32 PPV strains was constructed using the Bayesian Markov Chain Monte Carlo (MCMC) method. The results showed that strain GD2013 fell into the same phylogenetic cluster as the classical vaccine strains NADL-2 and POVCAP, suggesting a close relationship to the vaccine strains. Multiple sequence alignments and amino acid mutation analyses of the PPV VP2 gene revealed a new amino acid polymorphism site at Thr45 on VP2 that could be used to identify low virulence strains as vaccine candidates. Selective pressure analysis of the NS1 and VP2 genes by calculating the mean rates of non-synonymous substitutions (dN) over synonymous substitutions (dS) implied that both of these genes were under negative selection. Therefore, by using phylogenetic and amino acid mutation analyses, a likely candidate strain suitable for evaluation as an attenuated vaccine strain was identified.

Poultry mesenchymal stem cells：exploration and prospects / 中国组织工程研究

BACKGROUND:Poultry mesenchymal stem cels are a particular subset of pluripotent adult stem cels derived from the mesoderm, which have great application prospects because of their strong proliferation and multi-directional differentiation potential. OBJECTIVE:To review the source, separation, purification, culture and differentiation of poultry mesenchymal stem cels, and to provide the theoretical foundation and experimental basis for the further research and application of poultry mesenchymal stem cels. METHODS:PubMed and CNKI databases were searched by the first author using key words of “mesenchymal stem cels, poultry, chicken, isolation, culture, differentiation” in English and in Chinese, respectively, to retrieve relevant articles published from 1990 to 2014. Literatures addressing induced poultry mesenchymal stem cels were included, and 42 articles were chosen for further analysis eventualy. RESULTS AND CONCLUSION: Poultry mesenchymal stem cels have great application prospects in the aspects of establishingin vitro model of poultry cels, studying poultry disease pathogenesis, animal nutrition and meat quality control. Its origin source is wide and easy to obtain. Isolation, purification, culture and biological characteristics of mesenchymal stem cels from different tissues are different. But, the study on poultry mesenchymal stem cels is stil in the exploration process, and there are many technical problems to be solved.

Sequence analysis of the protein-coding regions of foot-and-mouth disease virus O/HK/2001.

The nucleotide sequence of the protein-coding region of foot-mouth-disease virus (FMDV) strain O/HK/2001 was determined and compared with the sequences of other FMDVs that were registered in GenBank. The protein-coding region was 6966 nucleotides in length and encoded a protein of 2322 amino acid residues. Comparison of the nucleotide sequence and its deduced amino acid sequence with those of other isolates indicated that O/HK/2001 belonged to the Cathay topotype. A genomic coding region nucleotide sequence phylogenetic tree of several FMDV-O isolates showed that O/HK/2001 was most closely related to FMDV isolates found in Taiwan during 1997, and especially shared significant similarity to HKN/2002, suggesting that the virus causing outbreaks in Hong Kong was genetically most-closely related to that causing an outbreak of type O in Taiwan. Mutations in O/HK/2001 were revealed, including frequent substitutions in the VP1 and L proteins, and deletions involving 10 amino acid residues in the 3A protein. This study was undertaken to assess the regional variation of prevalent FMDV type O viruses and to establish a sequence database for FMDV molecular epidemiological investigation.

Molecular characterization of foot-and-mouth disease virus in Hong Kong during 2001-2002.

Most of the molecular epidemiological studies of foot-and-mouth disease virus (FMDV) are based on comparison of VP1 gene sequence. In this report, The nucleotide sequences of the VP1 coding region of FMDV type O strains O/HKN/3/01, O/HKN/5/01, O/HKN/12/01, O/HKN/7/02 and O/HKN/10/02, isolated from the disease outbreak that occurred in Hong Kong Special Administrative Region (Hong Kong SAR) of China during 2001-2002, were determined and compared with the sequences of other FMDVs. The results revealed that the VP1 gene of the five isolates had the same nucleotide (nt) sequences (639 nt), coding for 213 amino acids, and no changes were found either at the critical amino acid sites 144 (Val), 148 (Leu), 154 (Lys) and 208 (Pro) within the VP1 protein epitope (amino acids 140-160, 200-213), or in the amino acids 145-147 comprising the arginine-glycine-aspartic acid (RGD) sequence that is involved in the adsorption of virus to host cell. Analysis of the VP1 gene nucleotide sequence revealed that the five isolates examined were most closely related to FMDVs found in Hong Kong from 1991 to 1999 and Taiwan in 1997. Furthermore, although the critical amino acids on the antigen epitope of the prevalent Hong Kong isolates and the serotype O vaccine strain, O1/Manisa/Turkey/69, showed relative conservativeness, they were distantly related genetically, which showed that there existed variation between the prevalent Hong Kong FMDV strains and the vaccine strain.

A goose-sourced paramyxovirus isolated from southern China.

We report the isolation and characterization of a paramyxovirus from geese in South China during 1997. The isolate, designated as goose paramyxovirus/QingYuan 1997-1 (GPMV/QY97-1), showed pathogenicity to geese and could agglutinate chicken erythrocytes. Its hemagglutinating activity was inhibited by antiavian paramyxovirus serotype 1 (APMV-1) serum. The F gene of isolate was amplified by reverse transcription polymerase chain reaction, and sequence analysis proved that its sequence conformed to that reported in the literature, encoding an F0 protein of 553 amino acids with 13 cysteine residues and 6 potential glycosylation sites. It also contained multiple basic amino acids at the deduced cleavage site of the fusion protein, which is a typical feature of highly virulent APMV-1 strains. Sequences analysis of the F gene of GPMV/QY97-1 revealed a homology with other APMV-1 isolates, with its identity ranging from 84.1% to 99.9% on a nudeotide basis and from 88.8% to 99.6% on an amino acid basis. Phylogenetic analysis of the APMV-1 isolates showed that this isolate most closely resembled the reference APMV-1 strain GD/1/98/Go, which was originally isolated from geese in 1998.