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Bai J.L.,Gansu Engineering Research Center for Animal Cell | Bai J.L.,Northwest University for Nationalities
Journal of Applied Animal Research | Year: 2015

To estimate the phylotaxonomic position of Tianzhu white yak (Poephagus grunniens), multiple subunit genes of cytochrome c oxidase (cox) were sequenced: 1545 bp of cox1 (JF946751), 684 bp of cox2 (JN008944) and 781 bp of cox3 (JF946752). Sequence divergences of cox genes between yaks and cattle/zebus (5.7% in cox1, 7.7% in cox2 and 6.45% in cox3) were higher than those between yaks and American bisons (2.4% in cox1, 3.0% in cox2 and 2.1% in cox3). Molecular phylogenetic analysis with these genes also found that yaks and American bisons firstly clustered in one clade, indicating there was higher genetic comparability than that of cattle/zebus. The findings sustained the idea that in the choice of nomenclature yaks belong to the subgenus of Poephagus. According to the nucleotide substitution rate of cox genes among species of Bovinae, the speculated divergence time of yaks from cattle/zebus, American bisons, European bisons, Asian buffaloes/African buffaloes was 1.05-1.50 million years ago (MYA), 2.85-3.89 MYA, 2.90-3.70 MYA, 6.85-7.50 MYA, respectively. The sequential evolution of Bovinae members could be predicted that buffaloes were first to be domesticated during the end of Miocene and the early of Pliocene. In the end of Pliocene, the Bovinae genera were evolved to Bos, Bison and Poephagus. Poephagus was the latest evolved genera among the species of Bovinae. © 2014 Taylor & Francis.

Shen H.,South China Agricultural University | Pei J.,South China Agricultural University | Bai J.,Northwest University for Nationalities | Bai J.,Gansu Engineering Research Center for Animal Cell | And 9 more authors.
Virus Genes | Year: 2011

Classical swine fever virus (CSFV) causes a highly contagious disease that leads to significant economic losses in the pig industry worldwide. However, there is a paucity of knowledge on the accurate genotyping of CSFV isolates in south China. This study genotyped the E2 gene of 14 CSFV strains isolated during 2008-2010 from domestic pigs in different districts of south China. Phylogenetic analyses revealed that all of the 14 CSFV isolates were clustered into genetic subgroup 1.1. This contrasts with most parts of China, where group 2 isolates are predominant. Furthermore, the positive selection pressures acting on the E rns and E2 envelope protein genes of CSFV were assessed and a site-by-site analysis of the dN/dS ratio was performed to identify specific codons that undergo diversification under positive selection. While no significant evidence for positive selection was observed in E rns, two positively selected sites at amino acid residues 49 and 72 in the E2 encoding region were identified. Our results revealed that a predominance of subgroup 1.1 CSFV isolates is currently circulating in some districts of south China, which appear to be unrelated to the Chinese C-strain vaccine. Moreover, the envelope protein gene, E2, has undergone positive selection in 14 CSFV strains and two positively selected sites have been identified in this study. Understanding the molecular epidemiology and functional importance of these positively selected amino acid positions could help to predict possible changes in virulence, the development of vaccines and disease control. © 2011 Springer Science+Business Media, LLC.

Zang R.,Gansu Agricultural University | Zang R.,Northwest University for Nationalities | Bai J.,Northwest University for Nationalities | Bai J.,Gansu Engineering Research Center for Animal Cell | And 6 more authors.
Asian Journal of Animal and Veterinary Advances | Year: 2011

Real-time quantitative PCR (qPCR) is the most accurate method of quantifying gene expression, provided that suitable endogenous controls are used to normalize the data. To date, no reference genes have been validated for development in Lanzhou fat-tailed sheep (Ovis aries). We have determined the expression profiles of 7 housekeeping genes as candidate reference genes (Actb, Ywhaz, Sdha, Gapdh, Tubb2, Pgk1 and 18S rRNA) in 7 developmental stages (1, 3, 5, 7, 9, 11 and 13 months of age) and 6 tissues (omental fat, liver, tail fat, thigh muscle, subcutaneous fat (backfat above 12th and 13th rib) and perirenal fat) in Lanzhou fat-tailed sheep. The software packages geNorm, NormFinder and BestKeeper were used to evaluate the stability of potential reference genes; each produced comparable results. Initial results showed several of the candidate genes exhibited stable expression throughout development while Actb was identified as the least stable gene. Further analysis with geNorm, NormFinder and BestKeeper identified Gapdh, Tubb2, Sdha and Ywhaz as acceptably stable in gene expression. Comparison of diacylglycerol O-acyltransferase 1 (Dgat1) expression data normalized with geometric averages obtained from combinations of either Gapdh, Sdha, Ywhaz or Tubb2, Sdha, Ywhaz showed no significant differences, indicating that these two combinations are similar. The data provided in this paper may also be useful in guiding researchers performing gene expression in other species of sheep. © 2011 Academic Journals Inc.

Wei S.,Northwest University for Nationalities | Bai J.,Northwest University for Nationalities | Bai J.,Gansu Engineering Research Center for Animal Cell | Gong Z.,China Agricultural University | And 2 more authors.
Livestock Science | Year: 2011

The present study was conducted to assess the effects of active immunization against the gonadotropin-releasing hormone agonist (GnRHa) on ovary development and GnRH receptor mRNA expression levels in pituitary in Japanese white rabbits (Oryctolagus cuniculus). Twenty-four three-month-old rabbits were randomly divided into four groups (n = 6). The animals were subcutaneously injected with 100μg of GnRHa (alarelin) antigen in experimental group I (EG-I), 100μg in experimental group II (EG-II) and 50μg in experimental group III (EG-III) respectively. Alarelin antigens were re-injected in EG-II and EG-III with the same dosage on 20. days. CG was blank. The samples of ovaries and uteri were collected aseptically at the end of the experiment (70. days). Tissue slices were observed under light and electron microscopes. Serum anti-GnRH antibody titers and concentrations of FSH and LH were measured with ELISA. The anti-GnRH antibody titers reached the peak levels respectively at 30. days in EG-I (1:800), at 40-50. days in EG-II (1:1600) and at 40-50. days in EG-III (1:800). From 40 to 70. days, anti-GnRH antibody titers in EG-II were higher than that in EG-I and EG-III (p<0.05). The highest FSH levels in EG-II and EG-III were detected on 40. days. FSH level in EG-II was higher than those in EG-I, CG (p<0.01) and EG-III (p<0.05) on 40. days. There was no significant difference in FSH levels between EG-I and CG. Serum LH concentrations in EG-II and EG-III reached the peak levels on 50. days and 40. days, LH level in EG-II exceeded other 3 groups on 50. days (p<0.05). Real-time quantitative PCR analysis indicated that the levels of FSH-β mRNA and GnRH-R mRNA in pituitary significantly declined, while LH-β mRNA increased at 70. days following alarelin antigen treatment. The results also showed that alarelin antigen treatment improves the development of ovaries, follicles and uteri in Japanese white rabbits. Alarelin antigen treatment and re-injection with 100μg dose had better effects than 50μg treatment. This may have significance for the development of novel GnRH-based techniques in regulative functions in rabbits. © 2011.

Bai J.L.,Gansu Engineering Research Center for Animal Cell | Bai J.L.,Northwest University for Nationalities | Jiang J.Y.,Northwest University for Nationalities | Yang J.,Northwest University for Nationalities
Asian Journal of Animal and Veterinary Advances | Year: 2014

It is well known that yak is originated from China but fact regarding its taxonomy and evolutionary relationship with other species of Bovini, is largely disputed. Here, we cloned 1140 bp complete mitochondrial cytochrome b (cytb) gene in Tianzhu with yak (JF946750). The origin, taxonomy of the Chinese yak and its phylogenetic relationship with other 8 species of Bovini were discussed based on the cytb. Results showed that Tianzhu white yak had high identity to Qinghai black breed with the minimum sequence divergence of 0.5%. The sequence divergence between yak and cattle/zebu (8.0-8.5%) was higher than that between yak and American bison (3.4-4.1%). Phylogeny analysis also found that domestic yak and wild yak clustered first of all, then gathered with American bison and other Bovini species, indicating yak and American bison were higher genetic comparability than that of other species. The findings sustained the idea that in the choice of nomenclature both the domestic yak and the wild yak belong to the subgenus of Poephagus. The approximate divergence time between domestic yak and wild yak was 0.50 Million Years Ago (MYA), while the yak and cattle/zebu, American bison, European bison, Asian buffalo/African buffalo was 4.00-4.25, 1.7-2.05, 3.80-3.85 and 6.70-6.95 MYA, respectively. We speculated that the ancient yak lived in the northeastern part of Eurasia during the Quaternary had been shifted south to the cold area of the Qinghai Tibetan Plateau (QTP) during the metaphase of the Pleistocene era. Some of them acclimated to today's wild yak, the others were domesticated by the ancient Qiang people at least 4500 years ago. The sequential evolution could be predicted that buffalo was first to divided into Asian buffalo and African buffalo among the species of Bovini during the end of Miocene and the early of Pliocene. In the end of Pliocene, the Bovini genera were evolved to Bos, Bison and Poephagus. Poephagus which branched off from the middle of Pleiocene, was the latest evolved genera among the Bovini species. © 2014 Academic Journals Inc.

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