High Osmolarity Modulates Bacterial Cell Size through Reducing Initiation Volume in Escherichia coli.
High Osmolarity Modulates Bacterial Cell Size through Reducing Initiation Volume in Escherichia coli.
复制标题
高渗透压通过降低大肠杆菌的起始体积来调节细菌细胞大小
DOI：
10.1128/msphere.00430-18
复制
发表时间：
2018-10-24
期刊：
影响因子：
4.8
通讯作者：
Zhu M
中科院分区：
文献类型：
--
作者：
Dai X;Zhu M
细菌细胞大小取决于生长速率、细胞周期进程和启动染色体复制时每个起点的细胞体积（起始体积）。本研究首次系统定量地研究了高渗胁迫对E. coli细胞大小和细胞周期。我们发现，高渗应力显着降低起始体积。起始体积的减少归因于在高渗透压下由水损失引起的DnaA浓度增加，表明水含量在细胞大小和细胞周期调节中的基本作用。摘要细菌细胞大小与生物量生长和细胞周期进程密切相关，包括染色体复制和细胞分裂。一般认为，大肠杆菌细胞通过在各种生长条件下启动染色体复制时维持每个起点的恒定细胞体积（恒定起始体积）来严格控制染色体复制的时机。在这里，我们定量表征高渗胁迫下呈指数增长的大肠杆菌细胞的细胞大小和细胞周期，高渗胁迫是一种常见的环境应激源，深刻影响细菌含水量。细菌细胞大小减少高渗应力，即使C和D期显着延长，表明显着减少的起始体积。降低的起始体积源于在高渗透压下水分损失引起的较高浓度的DnaA起始蛋白。我们的研究表明，水含量在调节细菌细胞大小中的基本作用，并且还揭示了DnaA蛋白在调节染色体复制延伸中的新作用，而不仅仅是调节复制起始过程。细菌细胞大小取决于生长速率、细胞周期进程和启动染色体复制时每个起点的细胞体积（起始体积）。本研究首次系统定量地研究了高渗胁迫对E. coli细胞大小和细胞周期。我们发现，高渗应力显着降低起始体积。起始体积的减少归因于在高渗透压下由水损失引起的DnaA浓度增加，表明水含量在细胞大小和细胞周期调节中的基本作用。
Bacterial cell size depends on growth rate, cell cycle progression, and the cell volume per origin upon initiating chromosome replication (initiation volume). Here, we perform the first systematic and quantitative study of the effect of hyperosmotic stress on the E. coli cell size and cell cycle. We find that hyperosmotic stress significantly reduces the initiation volume. The reduced initiation volume is attributed to the increased DnaA concentration caused by water loss at high osmolarity, indicating a fundamental role of water content in cell size and cell cycle regulation. ABSTRACT Bacterial cell size is closely associated with biomass growth and cell cycle progression, including chromosome replication and cell division. It is generally proposed that Escherichia coli cells tightly control the timing of chromosome replication through maintaining a constant cell volume per origin upon initiating chromosome replication (constant initiation volume) under various growth conditions. Here, we quantitatively characterize the cell size and cell cycle of Escherichia coli cells growing exponentially under hyperosmotic stress, which is a common environmental stressor that profoundly affects the bacterial water content. The bacterial cell size is reduced by hyperosmotic stress, even though the C and D periods are remarkably prolonged, indicating a significantly reduced initiation volume. The reduced initiation volume originates from the higher concentration of DnaA initiator protein caused by water loss at high osmolarity. Our study shows suggests a fundamental role of water content in regulating bacterial cell size and has also revealed a new role of the DnaA protein in regulating the chromosome replication elongation beyond regulating the replication initiation process. IMPORTANCE Bacterial cell size depends on growth rate, cell cycle progression, and the cell volume per origin upon initiating chromosome replication (initiation volume). Here, we perform the first systematic and quantitative study of the effect of hyperosmotic stress on the E. coli cell size and cell cycle. We find that hyperosmotic stress significantly reduces the initiation volume. The reduced initiation volume is attributed to the increased DnaA concentration caused by water loss at high osmolarity, indicating a fundamental role of water content in cell size and cell cycle regulation.