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Zhang L.,China Agricultural University | Zhong C.,China Agricultural University | Wang J.,China Agricultural University | Lu Z.,China Agricultural University | And 4 more authors.
Virology Journal

Background: Since late 2011, cases of suspected canine pseudorabies have increased in north China with the outbreak of swine pseudorabies in the same area, but the pathogenesis of canine Pseudorabies virus (PRV) infections in China is poorly understood. In this study, we investigated the pathogenesis of canine pseudorabies. Methods: The pathological changes in 13 dogs that died of natural PRV infections (confirmed by pathogen detection) during 2011-2013 in Beijing were evaluated. An experimental study was also conducted in which healthy adult beagle dogs were administered PRV isolate BJ-YT by subcutaneous injection. The dog tissues were subjected to gross and microscopic examinations and immunohistochemical analysis and the dogs' serum cardiac troponin-I (cTn-I) was measured. Results: Systemic hemorrhage and/or congestion were the most marked pathological changes in both the naturally and experimentally PRV-infected dogs. Macroscopically, the major lesions consisted of petechiae and ecchymoses in both the endocardium and epicardium, thrombi in the mitral valves, hemorrhage in the lungs and thymus, and incomplete contraction of the spleen. Microscopically, the major histopathological findings were systemic hemorrhage and congestion, nonsuppurative ganglioneuritis (in the experimentally infected dogs, unexamined in the naturally PRV-infected dogs), brainstem encephalitis (in the naturally infected dogs), necrosis or exudation in the myocardium, and lymphoid depletion in many lymphoid organs and tissues. Viral antigens were only detected in the brainstems and peripheral ganglia of the infected dogs. Serum cTn-I was significantly higher in the experimentally PRV-infected dogs with myocardial lesions than in the dogs without myocardial lesions. Conclusions: Based on these results, we conclude that virally induced systemic hemorrhage, peripheral nervous system pathology, and/or cardiac injury can individually or collectively cause death in PRV-infected dogs. The respiratory signs of the disease are attributed to cardiogenic lesions. © 2015 Zhang et al.; licensee BioMed Central. Source

Wu J.,China Animal Husbandry Industry Co. | Wu J.,Key Laboratory of Biological Products and Chemical Drugs for Animals | Wu J.,China Animal Husbandry Group | Huang Y.,CAS Institute of Process Engineering | And 13 more authors.
Shengwu Gongcheng Xuebao/Chinese Journal of Biotechnology

Enramycin is a polypeptide antibiotic and new, safe animal feed additive. A new purification process was developed, based on pre-purification by macroporous resin and refining by reversed phase chromatography. AB-8 macroporous resin was used for the pre-purification process of enramycin, with an elution buffer of 0.012 mol/L aqueous HCl solution-methanol (50:50, V/V). Then, enramycin a and enramycin b were separated effectively by C18 reversed phase chromatography, with a elution buffer of 0.05 mol/L aqueous KH2PO4 solution-acetonitrile (70:30, V/V, pH 4.5). The purities of enramycin a and enramycin b were up to 98.5% and 98.0%, respectively. The yield reached 29.2%. This study would provide a useful reference for the preparation of enramycin a and enramycin b with ahigh purity. © 2014 Chin J Biotech, All rights reserved. Source

Yao Z.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Zhao C.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Yang K.,China Animal Husbandry Group | Liu W.,China Animal Husbandry Group | And 3 more authors.

Degradation of semiarid grassland and efforts to control that degradation have become pressing issues. However, the inherent characteristics of the grassland and the intertemporal nature of the problem complicate the analysis of degradation issues, and consequently, the search for more appropriate rangeland policies. Using the Damaying Grassland as a case study, we assessed alpine grassland on the north slopes of the Qilian Mountains by means of in situ samples using vegetative cover, biological diversity, forage productivity, soil bulk density, and soil nutrients as the main evaluation indices. The forage yields on high, moderate, and low coverage rangeland exhibited decreases of 20.2%, 20.8% and 56.4%, respectively, from 1982 to 2012. Due to the lower basal cover of rangeland in poor condition, soil nutrient and organic matter content decreased with rangeland degradation. Increased soil compaction appears to lead to lower basal cover of rangeland The soil bulk density in high, moderate, and low coverage rangelands was found to be 0.8g·cm-3, 1.1g·cm-3, and 1.2g·cm-3, respectively. The soil nutrient levels and organic matter contents indicate that the rangelands experienced degradation over the 30-year period. Organic matter and available nitrogen decreased significantly over time, while available phosphorus and available potassium increased significantly. Overall, our results show that the Damaying Grassland is in a period of rapid degradation, and that mitigation and remediation measures are needed to protect the rangelands. © 2015. Source

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