猪繁殖与呼吸综合症(porcine productive andrespiratory syndrome,PRRS)是由猪繁殖与呼吸综合征病毒引起的以母猪繁殖障碍和仔猪呼吸哀竭为主要症状的传染病,该病近年来大面积发生于我国境内,引起养猪业的巨大损失。
中国科学院动物研究所何宏轩研究组,采用RT-PCR技术对2008年分离自河北石家庄地区的7株(LS-4, HM-1, HQ-5, HQ-6, GC-2, GCH-3和 ST-7)猪繁殖与呼吸综合征病毒(PRRSV)进行GP2, GP3, GP4, GP5 和 NSP2 基因的扩增、克隆和测序,与已知序列的毒株的相应片段进行同源性分析比较,并对其分子特征进行分析。结果表明:这7株病毒仍属北美基因型,同源性分析表明这些病毒株与北美洲原型代表株(VR-2332株)有80.8-92.9%的同源性,与疫苗毒MLV有81.3-98.8%的同源性,与BJ-4株有80.7-92.9%同源性。所有这七株变异病毒的NSP2蛋白都存在一个29个氨基酸序列的缺失,赋予了这些病毒新的特征,而且这些氨基酸序列的缺失与病毒高致病性有关,与河北省其它的分离株虽属于同一个大的分支,但这些毒株的gp5蛋白存在广泛的突变。
这一研究结果表明了目前猪的PRRSV病毒可能存在一种由传统毒株向高致病性毒株演化的趋势,并为将来野猪PRRSV的疫苗研究和免疫防控奠定了基础。该工作得到国家科技部973、863和国家科技支撑项目支持。(生物谷Bioon.net)
生物谷推荐原文出处:
BMC Microbiology doi:10.1186/1471-2180-10-146
Phylogenetic analysis and molecular characteristics of seven variant Chinese field isolates of PRRSV
Chengmin Wang1 , Bin Wu1,2 , Said Amer1,4 , Jing Luo1 , Hongmei Zhang3 , Yunhai Guo1 , Guoying Dong1 , Baohua Zhao2 and Hongxuan He1
1 National Research Center for Wildlife Born Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
2 College of Life Science, Hebei Normal University, Shijiazhuang, Hebei, 050060 China
3 Department of Life Science, Heze College, Heze, Shandong Province 274015 China
4 Department of Zoology, Faculty of Science, Kafr El-Sheikh 33516 Egypt
Background
Porcine reproductive and respiratory syndrome (PRRS) has now been widely recognized as an economically important disease. The objective of this study was to compare the molecular and biological characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) field isolates in China to those of the modified live virus (MLV) PRRS vaccine and its parent strain (ATCC VR2332).
Results
Five genes (GP2, GP3, GP4, GP5 and NSP2) of seven isolates of PRRSV from China, designated LS-4, HM-1, HQ-5, HQ-6, GC-2, GCH-3 and ST-7/2008, were sequenced and analyzed. Phylogenetic analyses based on the nucleotide sequence of the ORF2-5 and NSP2 showed that the seven Chinese isolates belonged to the same genetic subgroup and were related to the North American PRRSV genotype. Comparative analysis with the relevant sequences of another Chinese isolate (BJ-4) and North American (VR2332 and MLV) viruses revealed that these isolates have 80.8-92.9% homology with VR-2332, and 81.3-98.8% identity with MLV and 80.7-92.9% with BJ-4. All Nsp2 nonstructural protein of these seven isolates exhibited variations (a 29 amino acids deletion) in comparison with other North American PRRSV isolates. Therefore, these isolates were novel strain with unique amino acid composition. However, they all share more than 97% identity with other highly pathogenic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and the Nsp2 protein when compared with the previous isolates.
Conclusions
These results might be useful to study the genetic diversity of PRRSV in China and to track the infection sources as well as for vaccines development.