摘要
以广州动物园小熊猫体内分离出的蛔虫为研究对象,运用PCR方法,以保守引物NC5和NC2扩增其核糖体DNA(rDNA)的内转录间隔区(ITS)和5.8S序列,并对扩增后的片段进行纯化、克隆至pGEM-Teasy载体、转化、测序和序列分析,以鉴定小熊猫蛔虫的种类。结果显示2条蛔虫样品的ITS及5.8S rDNA序列基本一致,总长为913 bp,样品间序列相似性为99.7%。将序列与GenBank^(TM)公布的相关序列进行比较分析,结果显示2条蛔虫的ITS及5.8S序列与黑熊横走贝蛔虫(Baylisascaris transfuga注册号AB571304)相似性分别为98.1%、98.4%,与大熊猫西氏贝蛔虫(Baylisascaris schroederi注册号JN210912)相似性分别为96.9%、97.1%,与猪蛔虫(Ascaris suum注册号AB571302)相似性分别为89.9%、90.1%,与人蛔虫(Ascaris lumbricoides注册号AB571296)相似性分别为89.8%、90.1%,ITS-1序列与浣熊贝蛔虫(Baylisascaris procyonis注册号AB053230)相似性分别为92.0%、92.3%。研究结果表明小熊猫体内分离的蛔虫可能为贝蛔属蛔虫,从而为蛔虫的进一步分类、鉴定和遗传变异研究奠定了基础。
Our research objective was to identify ascarid samples isolated from a red panda at the Guangzhou Zoo. The internal transcribed spacer （ITS） and 5.8S of ribosomal DNA （rDNA） of two ascarid samples were amplified by PCR using a pair of conserved primers （ NC5 and NC2 ） , and the amplified products were purified, cloned and sequenced. The lengths of se-quences （ ITS and 5.8S rDNA） from two samples were both 913 bp, and the similarity of sequences was 99. 7% between the two ascarid samples. The similarities of ITS and 5.8S sequences were 98. 1% and 98.4%, respectively , compared with the relevant sequences of Baylisascaris transfuga （ AB571304 ） available from GenBankTM. Similarities were 96. 9% and 97. 1%compared with Baylisascaris schroederi （JN210912） , 89.9% and 90. 1% compared with Ascaris suum （AB571302） , 89.8% and 90. 1% compared with Ascaris lumbricoides （AB571296） , and 92.0% and 92. 3% compared with the ITS - 1 sequence of Baylisascaris procyonis （ AB053230） . We conclude that the asearid nematodes might represent Baylisascaris sp. This research, provided a foundation for further studies of molecular identification and molecular genetics of ascarid.
