保定地区奶牛源隐孢子虫的分离与基因鉴定

为了解保定地区奶牛源隐孢子虫感染情况,从当地3个奶牛场随机采集145份奶牛粪便经饱和蔗糖溶液漂浮后直接镜检和抗酸染色后镜检,阳性样品采用PCR方法扩增18S rRNA基因,同时将扩增出的目的片段进行克隆和序列分析,并将分离株与其他11个隐孢子虫参考株的18S rRNA序列进行比对和遗传距离比较。结果表明:有10份粪便样本为隐孢子虫阳性,感染率为6.9%(10/145),不同奶牛场、年龄段奶牛隐孢子虫感染率有显著性差异(P<0.05)。10份粪便样品采用PCR方法扩增后有7份为18S rRNA基因阳性,扩增出的18S rRNA部分基因片段长528 bp。保定地区隐孢子虫分离株扩增的基因序列与牛源隐孢子虫18S rRNA基因序列(Gen Bank登录号为HQ179571)同源性最高,确定保定地区分离到的奶牛源隐孢子虫为牛隐孢子虫。

荧光原位杂交法对血培养常见菌的快速鉴定

目的 建立快速鉴定阳性血培养的荧光原位杂交法。方法 针对血培养中的常见病原菌 ,以细菌 16SrRNA和真菌 18SrRNA为靶序列 ,设计种属特异性的寡核苷酸探针。BacT/ALERT仪器报警后 ,取阳性血培养液 15 μl于玻片上 ,5 0℃杂交 1h ,然后 5 0℃下洗涤缓冲液洗涤 10min ,荧光显微镜下检测鉴定结果。同时对临床标本进行常规培养鉴定。结果 118份阳性血培养标本中 ,116份标本杂交法检测为阳性 ,敏感率为 98.3%。除少数阴性杆菌 ,阳性杆菌不能鉴定至种属的水平外 ,92 .5 %的病原体可于 2h内鉴定至种或属的水平。结论 荧光原位杂交法可快速鉴定血培养中的常见菌 。

Ribosomal DNA gene and phylogenetic relationships of Diplura and lower Hexapods

The monophyly of Diplura and its phylogenetic relationship with other hexapods are important for understanding the phylogeny of Hexapoda. The complete 18SrRNA gene and partial 28SrRNA gene (D3-D5 region) from 2 dipluran species (Campodeidae and Japygidae), 2 proturan species, 3 collembolan species, and 1 locust species were sequenced. Combining related se-quences in GenBank, phylogenetic trees of Hexapoda were constructed by MP method using a crustacean Artemia salina as an outgroup. The results indicated that: (i) the integrated data of 18SrDNA and 28SrDNA could provide better phylogenetic information, which well supported the monophyly of Diplura; (ii) Diplura had a close phylogenetic relationship to Protura with high boot-strap support.