Lebaron P, Joux F
Université Pierre et Marie Curie (Paris VI), URA117, Centre National de la Recherche Scientifique, Banyuls-sur-Mer, France.
Appl Environ Microbiol. 1994 Dec;60(12):4345-50. doi: 10.1128/aem.60.12.4345-4350.1994.
Flow cytometry was used to investigate the heterogeneity of the DNA content of Salmonella typhimurium and Alteromonas haloplanktis cells that were starved and allowed to recover in seawater. Hoechst 33342 (bisbenzimide) was used as a DNA-specific dye to discriminate between DNA subpopulations. The DNA contents of both strains were heterogeneous during starvation. S. typhimurium cells contained one or two genomes, and A. haloplanktis cells contained up to six genomes. S. typhimurium genomes were fully replicated at the onset of starvation. Each replication cycle was completed in the early stage of starvation for A. haloplanktis by stopping cells in the partition step of the cell cycle prior to division. Multigenomic marine cells can undergo rapid cell division without DNA synthesis upon recovery, resulting in large fluctuations in the DNA contents of individual cells. In contrast, the heterogeneity of the DNA distribution of S. typhimurium cells was preserved during recovery. The fluctuations in the DNA fluorescence of this strain seem to be due to topological changes in DNA. Flow cytometry may provide a new approach to understanding dynamic and physiological changes in bacteria by detecting cellular heterogeneity in response to different growth conditions.
采用流式细胞术研究了鼠伤寒沙门氏菌和嗜盐浮游交替单胞菌在海水中饥饿及恢复过程中DNA含量的异质性。用Hoechst 33342（双苯甲酰亚胺）作为DNA特异性染料来区分DNA亚群。在饥饿期间，两种菌株的DNA含量均具有异质性。鼠伤寒沙门氏菌细胞含有一个或两个基因组，嗜盐浮游交替单胞菌细胞含有多达六个基因组。鼠伤寒沙门氏菌基因组在饥饿开始时已完全复制。嗜盐浮游交替单胞菌在饥饿早期通过在细胞周期的分裂前分区步骤中使细胞停滞而完成每个复制周期。多基因组海洋细胞在恢复时可在不进行DNA合成的情况下快速进行细胞分裂，导致单个细胞的DNA含量大幅波动。相比之下，鼠伤寒沙门氏菌细胞DNA分布的异质性在恢复过程中得以保留。该菌株DNA荧光的波动似乎是由于DNA的拓扑变化。流式细胞术可能通过检测细胞对不同生长条件的异质性，为理解细菌的动态和生理变化提供一种新方法。
