Flagella are the well‐known structural appendages used by bacteria for motility. Although generally reported to be non‐motile, the enteropathogenic bacterial species Escherichia albertii produces flagella intermittently. We found that E. albertii expressed flagella under specific environmental conditions. After several generations (involving 4 to 12‐h incubations), six of the twelve strains we investigated displayed swimming motility in various aquatic environments, including pond water containing nutrients from pigeon droppings (10% suspension) as well as in 20 × −diluted tryptic soy broth. The most significant motility determinant was a temperature between 15 and 30 °C. At 20 °C in the 10% pigeon‐dropping suspension, microscopic observations revealed that some cells (1%–95% of six strains) showed swimming motility. Electron microscopy showed that the E. albertii cells expressed flagella. Lower concentrations of some substrates (including nutrients) may be of secondary importance for E. albertii flagella expression. Interestingly, the non‐motile strains (n = 6/12) contained pseudogenes corresponding to essential flagella structural proteins. After being released from its host into surface water, E. albertii may express flagella to move toward nutrient sources or new hosts.

中文翻译：

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人畜共患病病原体大肠埃希氏菌的鞭毛表达和游泳活性。

鞭毛是细菌用于运动的众所周知的结构性附件。尽管一般认为不运动，但肠致病性细菌种艾氏埃希氏菌会间歇性产生鞭毛。我们发现大肠埃希氏菌在特定环境条件下表达鞭毛。经过数代（涉及4到12小时的孵化），我们调查的十二种菌株中有六种在各种水生环境中表现出游泳运动性，包括含有来自鸽子粪便（悬浮液10％）的营养的池塘水中以及在20×-稀释的胰蛋白酶中大豆汤。最重要的运动决定因素是15至30°C之间的温度。在10％落鸽的悬浮液中，在20°C时，显微镜观察表明，某些细胞（六个菌株中的1％–95％）显示出游泳运动力。电子显微镜显示，艾伯氏大肠杆菌细胞表达鞭毛。某些底物（包括营养物质）的较低浓度可能对艾伯氏大肠杆菌具有次要的重要性。鞭毛表达。有趣的是，非运动菌株（n = 6/12）含有对应于必需鞭毛结构蛋白的假基因。从其宿主释放到地表水中后，艾伯氏大肠杆菌可能表达鞭毛，向营养源或新宿主迁移。