Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, Zurich CH 8092, Switzerland.
Nat Commun. 2016 Nov 23;7:13631. doi: 10.1038/ncomms13631.
L-forms are cell wall-deficient bacteria that divide through unusual mechanisms, involving dynamic perturbations of the cellular shape and generation of vesicles, independently of the cell-division protein FtsZ. Here we describe FtsZ-independent mechanisms, involving internal and external vesicles, by which Listeria monocytogenes L-forms proliferate. Using micromanipulation of single cells and vesicles, we show that small vesicles are formed by invagination within larger intracellular vesicles, receive cytoplasmic content, and represent viable progeny. In addition, the L-forms can reproduce by pearling, that is, generation of extracellular vesicles that remain transiently linked to their mother cell via elastic membranous tubes. Using photobleaching and fluorescence recovery, we demonstrate cytoplasmic continuity and transfer through these membranous tubes. Our findings indicate that L-forms' polyploidy and extended interconnectivity through membranous tubes contribute to the generation of viable progeny independently of dedicated division machinery, and further support L-forms as models for studies of potential multiplication mechanisms of hypothetical primitive cells.
L 型细菌是细胞壁缺陷的细菌，它们通过不依赖于细胞分裂蛋白 FtsZ 的特殊机制进行分裂，这些机制涉及细胞形状的动态扰动和囊泡的产生。在这里，我们描述了李斯特菌 L 型细菌通过内部和外部囊泡进行的不依赖于 FtsZ 的增殖机制。我们使用单细胞和囊泡的微操作，表明小囊泡是通过大的细胞内囊泡的内陷形成的，接收细胞质内容物，并代表有活力的后代。此外，L 型细菌可以通过珠状（pearling）方式繁殖，即形成细胞外囊泡，这些囊泡通过弹性膜管暂时与母细胞相连。通过光漂白和荧光恢复，我们证明了细胞质的连续性和通过这些膜管的转移。我们的发现表明，L 型细菌的多倍体和通过膜管的广泛连接有助于独立于专用分裂机制产生有活力的后代，并进一步支持 L 型细菌作为潜在原始细胞增殖机制研究的模型。
