Berg Howard C
Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA.
Curr Biol. 2005 Aug 9;15(15):R599-600. doi: 10.1016/j.cub.2005.07.042.
When grown on a soft agar surface in a rich medium, cells of Salmonella typhimurium elongate, produce extra flagella and move over the surface in a coordinated manner. In mutants with defects in the chemotaxis signaling pathway, the agar plates remain dry and the cells' flagella are short. Recent work shows that the anti-sigma factor controlling late-gene flagellar synthesis is secreted less by flagella when things are dry: the flagellum senses wetness.
在富含营养的培养基中于软琼脂表面生长时，鼠伤寒沙门氏菌的细胞会伸长，产生额外的鞭毛，并以协调的方式在表面移动。在趋化信号通路存在缺陷的突变体中，琼脂平板保持干燥，细胞的鞭毛较短。最近的研究表明，控制晚期基因鞭毛合成的抗σ因子在环境干燥时从鞭毛分泌减少：鞭毛能感知湿度。
