【作者】 焦海宏；

【导师】 王晶钰；

【作者基本信息】 西北农林科技大学 ， 预防兽医， 2008， 硕士

【摘要】 猪圆环病毒2型(PCV-2)是引起猪断奶后多系统衰竭综合征等相关疾病的重要病原。本文采用PCR技术,对2006-2007年我国广西和湖南省区的PCV-2流行情况进行了检测和病毒全基因组克隆测序及分析。本研究对采集于我国广西和湖南等地的301份(广西140份,湖南161份)猪高热综合征病料进行了圆环病毒2型的PCR检测,共检出PCV-2阳性121例,其中广西54例PCV-2阳性率为38.5%;湖南67例,阳性率为41.6%,证明我国广西湖南两地PCV-2感染较严重,PCV-2是导致猪高热综合征的一个重要病原。本研究采用PCR技术分段扩增的方法,扩增来自广西和湖南的PCV-2病毒基因组核苷酸序列,进行克隆测序;测序结果用DNASTAR软件进行序列拼接和分析,共得到病毒的全基因核苷酸序列24株,各毒株的核苷酸序列均为1767bp。通过流行毒株的基因序列分析发现,本试验获得的24个毒株的核苷酸序列同源性在96.0 %～100%之间,各毒株的ORF1同源性很高(97.1%～100%),而ORF2的同源性相对较低(93.3%～99.6%),病毒基因组的变异主要由ORF2基因的变异所致,两省区的毒株在核苷酸序列的同源性上无明显的地理差异。各毒株在基因进化树上同处在属于PCV-2的分支内,均为PCV-2,而且分处在PCV-2的两个较大分支内;其中GXI103、HUN321、HUN377、HUN432等4个毒株同处在PCV-2的一个小分支,其余20株处在另一个小分支;各毒株与加拿大、美国、欧洲和亚洲其它国家的PCV-2代表株有很近的亲缘关系。更多还原

【Abstract】 In this study,301 samples which were based on clinical signs for“Hot pig diseases”were detected for PCV2 by PCR. 121 samples (54 samples form Guangxi,and 67 samples from Hunan)were positive for PCV-2, and 24 porcine circovirus 2 strains of positive samples were cloned and sequenced.The complete genome of each the isolates was 1767bp in length.Comparison of complete genome sequence of the isolates in DNAStar showed that there was a 96.0%～100% identity of the complete genomic nucleotides .Analysise of the two open reading frames(ORF l and ORF2) and deduce their amino acid sequences in computer,we found that the ORF1 of the isolates showed 97.1%～100% nucleotide sequence identidy and 97.5%～99.7% amino acid identidy.The resμLt showed a high degree of homology of ORF 1 .The ORF2 of the isolates had 93.3%～99.6% nucleotide sequence identidy and 92.7%～99.6% amino acid identidy.Sequence analysis of ORF1 and ORF2 genes of 24 strains revealed that the extent of nucleotide variation was greater for the ORF2 than for the ORF 1.Phylogenetic analysis of the isolates of PCV-2 and other 17 PCV-2 and 1 PCV-1 sequences published in GenBank was obtained in Clustal w method.The result showed that the two viruses were found in different phylogenetic clusters,The 24 isolates of PCV2 were divided into two small groups,The strains were spread in small group.Comparison of nucleotide sequence confirmed that the 24 isolates were close to the isolates from France , Canada, the US and Asian..更多还原