Cell-Size Homeostasis and the Incremental Rule in a Bacterial Pathogen
Cell-Size Homeostasis and the Incremental Rule in a Bacterial Pathogen
复制标题
DOI：
10.1016/j.bpj.2015.07.002
复制
发表时间：
2015-08-04
影响因子：
3.4
通讯作者：
Xavier, Joao B.
中科院分区：
文献类型：
--
作者：
Deforet, Maxime;van Ditmarsch, Dave;Xavier, Joao B.
生长中的细胞群体如何实现细胞大小的动态平衡仍然是细胞生物学中的一个主要问题。最近对杆状细菌的研究支持“增量规则”，即每个细胞在分裂前增加一个恒定的长度。尽管这一规则解释了细胞大小的狭窄分布，但其机制仍不清楚。我们发现，条件致病菌铜绿假单胞菌在指数生长过程中遵循增量规律达到细胞长度的动态平衡，但在进入稳定期时细胞长度变短。我们发现了一种名为Frik的突变体，它增加了对抗生素的敏感性，细胞的平均长度更长，部分丝状细胞的长度超过10微米。当进入稳定期生长放缓时，Frik细胞的大小分布变小，接近野生型的长度分布。罕见的丝状细胞具有异常大的类核，这表明DNA分离的缺陷阻止了细胞分裂，而不会减缓指数延长率。
How populations of growing cells achieve cell-size homeostasis remains a major question in cell biology. Recent studies in rod-shaped bacteria support the "incremental rule" where each cell adds a constant length before dividing. Although this rule explains narrow cell-size distributions, its mechanism is still unknown. We show that the opportunistic pathogen Pseudomonas aeruginosa obeys the incremental rule to achieve cell-length homeostasis during exponential growth but shortens its cells when entering the stationary phase. We identify a mutant, called frik, which has increased antibiotic sensitivity, cells that are on average longer, and a fraction of filamentous cells longer than 10 mu m. When growth slows due to entry in stationary phase, the distribution of frik cell sizes decreases and approaches wild-type length distribution. The rare filamentous cells have abnormally large nucleoids, suggesting that a deficiency in DNA segregation prevents cell division without slowing the exponential elongation rate.