Archaeal cells share common size control with bacteria despite noisier growth and division
Archaeal cells share common size control with bacteria despite noisier growth and division
复制标题
DOI：
10.1038/s41564-017-0082-6
复制
发表时间：
2018-02-01
影响因子：
28.3
通讯作者：
Amir, Ariel
中科院分区：
文献类型：
--
作者：
Eun, Ye-Jin;Ho, Po-Yi;Amir, Ariel
在自然界中，微生物表现出跨越六个数量级的不同体积（1）。尽管它们能够产生不同的大小，但在给定环境中的克隆群体在单个细胞中保持一致的大小。最近在真核生物和细菌生物中的研究表明，细胞大小的这种均一性可以通过在两个细胞周期事件之间生长恒定的大小来实现（即加法模型（2-6））。加法模型的证明导致了这样的假设，即这种现象是趋同进化的结果。考虑到古细菌细胞与细菌和真核生物都具有相同的特征，我们研究了古细菌细胞是否以及如何控制细胞大小。为此，我们开发了一种生长古细菌细胞的软光刻方法，以实现定量延时成像和单细胞分析，这对其他微生物也很有用。使用这种方法，我们证明了盐生盐杆菌，一个高盐适应古生物，在单细胞水平上呈指数增长，并通过增加细胞分裂事件之间的恒定长度来保持窄分布。有趣的是，相对于在大肠杆菌中观察到的那些，古细菌细胞在细胞分裂位置和群体中单个细胞的指数生长速率方面表现出更大的变异性（6-9）。在这里，我们提出了一个理论框架，解释了古细菌细胞周期事件中这些较大的波动如何有助于细胞大小的变异性和控制。
In nature, microorganisms exhibit different volumes spanning six orders of magnitude(1). Despite their capability to create different sizes, a clonal population in a given environment maintains a uniform size across individual cells. Recent studies in eukaryotic and bacterial organisms showed that this homogeneity in cell size can be accomplished by growing a constant size between two cell cycle events (that is, the adder model(2-6)). Demonstration of the adder model led to the hypothesis that this phenomenon is a consequence of convergent evolution. Given that archaeal cells share characteristics with both bacteria and eukaryotes, we investigated whether and how archaeal cells exhibit control over cell size. To this end, we developed a soft-lithography method of growing the archaeal cells to enable quantitative time-lapse imaging and single-cell analysis, which would be useful for other microorganisms. Using this method, we demonstrated that Halobacterium salinarum, a hypersaline-adapted archaeal organism, grows exponentially at the single-cell level and maintains a narrow-ize distribution by adding a constant length between cell division events. Interestingly, the archaeal cells exhibited greater variability in cell division placement and exponential growth rate across individual cells in a population relative to those observed in Escherichia coli(6-9). Here, we present a theoretical framework that explains how these larger fluctuations in archaeal cell cycle events contribute to cell size variability and control.