All well-established cell size homeostasis paradigms are based on the researches of rod bacteria like B. subtilis and E. coli, suggesting a constant division time (timer model), division size (sizer model) or added size (adder model) before division. However, Lysinibacillus varians, a new species with regular filament-to-rod cell cycle, is inconsistent with existing models. In this study, the cell size parameters of the type strain GY32, were investigated by combing multiple microscopy techniques and single-cell approach. Our results showed that the filaments of strain GY32 were unicellular cells with multiple nucleoids. The division time of GY32 cells was variable and their daughter cells produced by asymmetric binary fission had different birth sizes, which were proportional to their elongation rates, resulting in high heterogeneity among the sister cells. Furthermore, the added size from birth to division was significantly shorter than birth size (p < 0.01) and decreased along generations. The results above revealed that the asymmetric division site and varied cell size parameters resulted in filament-to-rod cell cycle of L. varians and cell size homeostasis could be a more complex and dynamic process than previously assumed. These findings would be helpful in elucidating the open questions in cell division and cell size heterogeneity.

中文翻译：

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可变的细胞分裂时间和不对称分裂位点导致变异赖氨酸芽孢杆菌的丝状细胞周期。

所有成熟的细胞大小稳态范式均基于对枯草芽孢杆菌和大肠杆菌等杆状细菌的研究，表明在分裂前有恒定的分裂时间（计时器模型）、分裂大小（sizer 模型）或增加的大小（加法器模型） . 然而，Lysinibacillus varians 是一种具有规律的细丝到棒状细胞周期的新物种，与现有模型不一致。在这项研究中，通过结合多种显微镜技术和单细胞方法研究了 GY32 型菌株的细胞大小参数。我们的研究结果表明，菌株 GY32 的细丝是具有多个类核的单细胞细胞。GY32细胞的分裂时间是可变的，不对称二元裂变产生的子细胞具有不同的出生大小，这与它们的伸长率成正比，导致姐妹细胞之间的高度异质性。此外，从出生到分裂的增加的大小显着短于出生大小（p < 0.01），并且随着世代的增加而减少。上述结果表明，不对称分裂位点和不同的细胞大小参数导致 L. varians 的丝状细胞周期和细胞大小稳态可能是一个比以前假设的更复杂和动态的过程。这些发现将有助于阐明细胞分裂和细胞大小异质性方面的开放性问题。变异和细胞大小的稳态可能是一个比以前假设的更复杂和动态的过程。这些发现将有助于阐明细胞分裂和细胞大小异质性方面的开放性问题。变异和细胞大小的稳态可能是一个比以前假设的更复杂和动态的过程。这些发现将有助于阐明细胞分裂和细胞大小异质性方面的开放性问题。