Department of Microbiology, University of Umeå, S-901 87 Umeå, Sweden.
Appl Environ Microbiol. 1986 Jul;52(1):4-8. doi: 10.1128/aem.52.1.4-8.1986.
Minicells produced by Escherichia coli M2141 were used as probes to measure predation on pelagic bacteria in situ. The minicells, labeled with [S]methionine in one specific protein, were shown to disappear in the presence of a microflagellate (Ochromonas sp.), as seen by a decrease in the amount of labeled marker protein with time. Incubation in filtered (pore size, 0.2 mum) and autoclaved seawater did not affect the amount of labeled marker protein in the minicell. The generation time of flagellates feeding on minicells was determined to be similar to that found for flagellates grown on seawater bacteria or living E. coli NC3. Data indicate that minicells are seen as true food particles by the flagellates. The minicell probe was used in recapture experiments, in which predation in situ on pelagic bacteria was demonstrated. The rate of bacterial production showed a clear covariation with the rate of predation, both in different sea areas and in depth profiles. The obtained results (11 field experiments) showed that the rate of predation, on average, accounts for the consumption of 62% of the bacteria produced.
由大肠杆菌 M2141 产生的小型细胞被用作探针，以原位测量对浮游细菌的捕食作用。用 [S] 甲硫氨酸标记一个特定蛋白质的小型细胞，当存在微鞭毛虫（Ochromonas sp.）时会消失，这可以通过随着时间的推移标记标记蛋白的量减少来观察到。在过滤（孔径为 0.2 µm）和高压灭菌海水中孵育不会影响小型细胞中标记标记蛋白的量。以小型细胞为食的鞭毛虫的世代时间与在海水中细菌或活大肠杆菌 NC3 上生长的鞭毛虫的世代时间相似。数据表明，鞭毛虫将小型细胞视为真正的食物颗粒。小型细胞探针用于重新捕获实验，其中原位证明了对浮游细菌的捕食作用。细菌生产力的速率与捕食的速率明显相关，无论是在不同的海域还是在深度剖面中。获得的结果（11 个现场实验）表明，捕食的速率平均占所产生的细菌的 62%。
