Moreno-Fenoll Clara, Ardré Maxime, Rainey Paul B
Laboratory of Biophysics and Evolution, CBI, ESPCI Paris, Université PSL, CNRS, 75005 Paris, France.
Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany.
Microlife. 2024 Feb 14;5:uqae001. doi: 10.1093/femsml/uqae001. eCollection 2024.
Pyoverdin is a water-soluble metal-chelator synthesized by members of the genus and used for the acquisition of insoluble ferric iron. Although freely diffusible in aqueous environments, preferential dissemination of pyoverdin among adjacent cells, fine-tuning of intracellular siderophore concentrations, and fitness advantages to pyoverdin-producing versus nonproducing cells, indicate control of location and release. Here, using time-lapse fluorescence microscopy to track single cells in growing microcolonies of SBW25, we show accumulation of pyoverdin at cell poles. Accumulation occurs on cessation of cell growth, is achieved by cross-feeding in pyoverdin-nonproducing mutants and is reversible. Moreover, accumulation coincides with localization of a fluorescent periplasmic reporter, suggesting that pyoverdin accumulation at cell poles is part of the general cellular response to starvation. Compatible with this conclusion is absence of non-accumulating phenotypes in a range of pyoverdin mutants. Analysis of the performance of pyoverdin-producing and nonproducing cells under conditions promoting polar accumulation shows an advantage to accumulation on resumption of growth after stress. Examination of pyoverdin polar accumulation in a multispecies community and in a range of laboratory and natural species of , including PAO1 and KT2440, confirms that the phenotype is characteristic of .
绿脓菌素是由假单胞菌属成员合成的一种水溶性金属螯合剂，用于获取不溶性三价铁。尽管绿脓菌素在水性环境中可自由扩散，但它在相邻细胞间的优先传播、细胞内铁载体浓度的微调以及产生绿脓菌素的细胞相对于不产生绿脓菌素的细胞的适应性优势，都表明其在位置和释放方面受到控制。在此，我们利用延时荧光显微镜追踪SBW25生长微菌落中的单个细胞，结果显示绿脓菌素在细胞极积累。积累发生在细胞生长停止时，可通过在不产生绿脓菌素的突变体中进行交叉喂养实现，并且是可逆的。此外，积累与荧光周质报告基因的定位一致，这表明绿脓菌素在细胞极的积累是细胞对饥饿的一般反应的一部分。一系列绿脓菌素突变体中不存在非积累表型，这与该结论相符。对在促进极积累的条件下产生绿脓菌素和不产生绿脓菌素的细胞性能的分析表明，在应激后恢复生长时，积累具有优势。在多物种群落以及包括PAO1和KT2440在内的一系列实验室和自然假单胞菌物种中对绿脓菌素极积累的研究证实，该表型是假单胞菌属特有的。
