Granai C, Sjogren R E
Appl Environ Microbiol. 1981 Jan;41(1):190-5. doi: 10.1128/aem.41.1.190-195.1981.
A new device and procedure for the study of bacterial survival in an aquatic environment are described. The device uses two appressed presterilized microporous membranes to expose a bacterial cell suspension to the environment at a cell concentration that closely resembles those levels found in natural aquatic ecosystems. The device has been used under laboratory controlled conditions and in situ to study and compare bacterial survival times. In laboratory studies, Escherichia coli and Streptococcus faecalis survived the longest at 12 degrees C, pH 5, and in the presence of iron or calcium ions and cysteine. Cells in mid-stationary growth phase survived longer than those in mid- or late-logarithmic phase, whereas those maintained for a year or more as stock cultures survived for shorter period of time than did recent environmental isolates. In situ studies indicate that 5% of the starting number of E. coli and S. faecalis cells may survive longer than 96 h at 16 degrees C in potable lake water, whereas survival times in polluted lake water were approximately 12 h.
本文描述了一种用于研究细菌在水生环境中存活情况的新装置和方法。该装置使用两片紧密贴合的预灭菌微孔膜，以与天然水生生态系统中相近的细胞浓度，将细菌细胞悬液暴露于环境中。该装置已在实验室控制条件下和原位环境中用于研究和比较细菌的存活时间。在实验室研究中，大肠杆菌和粪肠球菌在12摄氏度、pH值为5、存在铁离子或钙离子以及半胱氨酸的条件下存活时间最长。处于生长中期稳定期的细胞比处于对数中期或后期的细胞存活时间更长，而作为保藏培养物保存一年或更长时间的细胞，其存活时间比近期从环境中分离得到的细胞要短。原位研究表明，在16摄氏度的饮用水湖中，初始数量的大肠杆菌和粪肠球菌细胞中有5%可能存活超过96小时，而在污染的湖水中存活时间约为12小时。
