Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States.
Front Cell Infect Microbiol. 2023 Oct 9;13:1205488. doi: 10.3389/fcimb.2023.1205488. eCollection 2023.
Most bacteria divide through a highly conserved process called binary fission, in which there is symmetric growth of daughter cells and the synthesis of peptidoglycan at the mid-cell to enable cytokinesis. During this process, the parental cell replicates its chromosomal DNA and segregates replicated chromosomes into the daughter cells. The mechanisms that regulate binary fission have been extensively studied in several model organisms, including , and . These analyses have revealed that a multi-protein complex called the divisome forms at the mid-cell to enable peptidoglycan synthesis and septation during division. In addition, rod-shaped bacteria form a multi-protein complex called the elongasome that drives sidewall peptidoglycan synthesis necessary for the maintenance of rod shape and the lengthening of the cell prior to division. In adapting to their intracellular niche, the obligate intracellular bacteria discussed here have eliminated one to several of the divisome gene products essential for binary fission in . In addition, genes that encode components of the elongasome, which were mostly lost as rod-shaped bacteria evolved into coccoid organisms, have been retained during the reductive evolutionary process that some coccoid obligate intracellular bacteria have undergone. Although the precise molecular mechanisms that regulate the division of obligate intracellular bacteria remain undefined, the studies summarized here indicate that obligate intracellular bacteria exhibit remarkable plasticity in their cell division processes.
大多数细菌通过一种高度保守的过程进行分裂，称为二分分裂，在此过程中，子细胞对称生长，肽聚糖在细胞中部合成，从而实现细胞分裂。在此过程中，亲代细胞复制其染色体 DNA，并将复制的染色体分配到子细胞中。在几个模式生物中，包括 、 和 ，对调节二分分裂的机制进行了广泛的研究。这些分析表明，一种称为分裂体的多蛋白复合物在细胞中部形成，以促进肽聚糖合成和分裂过程中的分隔。此外，杆状细菌形成一种称为伸长体的多蛋白复合物，驱动侧壁肽聚糖合成，这对于维持杆状形状和细胞在分裂前的伸长是必要的。为了适应其细胞内小生境，这里讨论的专性细胞内细菌消除了 中二分分裂所必需的一个或多个分裂体基因产物。此外，编码伸长体组件的基因在杆状细菌演变成球菌状生物时大多丢失，但在一些球菌状专性细胞内细菌经历的还原进化过程中被保留下来。尽管调节专性细胞内细菌分裂的确切分子机制尚不清楚，但这里总结的研究表明，专性细胞内细菌在其细胞分裂过程中表现出显著的可塑性。
