The study of symbiosis between bacteria and protozoa in intestinal environment, and mechanisms of transmission of pathogenic bacteria internalized with protozoal cyst

本研究旨在了解动物肠道内细菌与原生动物的共生关系。本研究从牛粪便中检出新的寄生原虫。提示在休眠原虫包囊状态下，肠道内有一定数量的活菌选择性存在，且在整个粪便中所占比例较小。一些厌氧肠道细菌可能利用肠道原生动物作为载体，不仅在自然环境中保护自己免受氧气的侵害，而且可能寻找机会传递给其他宿主。

This study aims to understand the symbiosis between bacteria and protozoa in animal intestine. In this study, the new parasitic protozoa were detected from fecal sample of cattle. And then it was suggested that some viable intestinal bacteria selectively existed in the dormant protozoa, i.e. cyst condition, and these bacteria accounted for minor population in the whole feces. Some anaerobic intestinal bacteria maybe use the intestinal protozoa for a vehicle, and not only defend itself from oxygen at natural environment but also may watch for an opportunity to pass on to other hosts.