Department of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, Florida 33703.
Appl Environ Microbiol. 1991 May;57(5):1509-15. doi: 10.1128/aem.57.5.1509-1515.1991.
We investigated the possibility for natural transformation in the marine environment by using broad-host-range plasmid multimers and a high-frequency-of-transformation (HFT) Vibrio strain as the recipient. Water and sediment samples were taken from Tampa Bay, the eastern Gulf of Mexico, the Florida Shelf near Miami, and the Bahamas Bank. In water column microcosms, transformation frequencies ranged from 1.7 x 10 to 2.7 x 10 transformants per recipient, with highest frequencies occurring when low levels of nutrients (peptone and yeast extract) were added. The presence of the ambient community either reduced transformation frequency by an order of magnitude or had no effect. In sterile sediments, nutrient additions had no consistent effect on transformation, with transfer frequencies similar to those observed in the water column. Transformation was not observed in any sediment experiment when the ambient microbial community was present. These findings are the first report of natural plasmid transformation in seawater and in the presence of the ambient microbial community. This process may be a mechanism for the acquisition of small, nonconjugative plasmids, which are commonly found in aquatic bacteria. Our data also suggest that natural transformation may be more likely to occur in the water column than in native marine sediments, contradicting prior conclusions based on studies with sterile sediments.
我们通过使用广谱宿主质粒多聚体和高频转化（HFT）弧菌菌株作为受体，研究了海洋环境中自然转化的可能性。从坦帕湾、墨西哥湾东部、迈阿密附近的佛罗里达大陆架和巴哈马群岛采集了水样和沉积物样本。在水柱微宇宙中，转化频率范围从每受体 1.7 x 10 到 2.7 x 10 个转化体，当添加低水平的营养物质（蛋白胨和酵母提取物）时，出现最高频率。环境群落的存在要么将转化频率降低一个数量级，要么没有影响。在无菌沉积物中，营养物质的添加对转化没有一致的影响，转移频率与水柱中观察到的相似。当环境微生物群落存在时，在任何沉积物实验中都没有观察到转化。这些发现是首次报道在海水中和环境微生物群落存在的情况下自然质粒转化。这个过程可能是获取小型非接合质粒的一种机制，这些质粒在水生细菌中很常见。我们的数据还表明，自然转化可能更有可能发生在水柱中，而不是在原生海洋沉积物中，这与基于无菌沉积物研究的先前结论相矛盾。
