异性孪生母牛的可育性鉴别和利用进展

异性孪生雌性不育是指异卵双胎或多胎后代中雌性个体不具备繁殖能力的现象,是牛最常见的先天性生育力异常现象。开发出能在早期快速、准确鉴别异性孪生母牛可育性的方法是牧场减少盲目留养或直接淘汰带来损失的现实需要,异种嵌合共生的异性孪生母牛也可以作为潜在的模式动物。本文从临床检查、免疫反应、激素检测、细胞分系和分子检测五个技术层面对异性孪生母牛可育性的鉴别方法进行总结,着重突出了现代细胞分子技术对鉴别准确性和时效性的提升作用;同时也归纳了异性孪生母牛在生产上作为种用或育肥资源的利用情况,并讨论了其作为模式动物研究人类器官移植、性腺发育和双胎输血综合征的潜力;最后,基于异性孪生母牛的研究现状,提出探究生殖激素与嵌合度及雄性化程度之间的关联性、从嵌合组织类型和嵌合时间结合细胞分子学以及内分泌学认识嵌合的本质和将异性孪生可育母牛作为免疫耐受性研究的动物模型这三个未来有潜力的研究方向,以推动异性孪生母牛的高效利用并发掘其背后的科研价值。

GyrB Gene Acts as a Phylogenetic Discriminator for Bacterial Diversity in Acid Mine Drainage

To study the efficiency ofDNA gyrase subunit B （gyrB） gene as means of diversity analysis, diversities of gyrB genes in three AMD samples collected from Dabaoshan Mine were studied by analyzing gyrB gene library. Many novel gyrB sequences and groups were detected. The results show that Acidithiobacillusferrooxidans-like bacteria represented 88.0% of the bacterial population in a sample. However, other two samples showed much high diversities. These diversities were characterized by the reciprocal of Simpson＇s index （l/D）, and show ferrous ion strongly influenced the composition of the microbial communities. The study indicate that gyrB Gene as a phylogenetic discriminator is a good tool to study different strains in same species that were difficult to be distinguished by 16S genes. But now gyrB Gene cannot define clearly unknown sequences to certain lineage, due to the incompleteness of the gyrB database.