Enterococcus faecalis Produces Abundant Extracellular Structures Containing DNA in the Absence of Cell Lysis during Early Biofilm Formation
Enterococcus faecalis Produces Abundant Extracellular Structures Containing DNA in the Absence of Cell Lysis during Early Biofilm Formation
复制标题
DOI：
10.1128/mbio.00193-12
复制
发表时间：
2012-07-01
期刊：
影响因子：
6.4
通讯作者：
Dunny, Gary M.
中科院分区：
文献类型：
--
作者：
Barnes, Aaron M. T.;Ballering, Katie S.;Dunny, Gary M.
粪肠球菌是后生动物胃肠道常见的革兰氏阳性细菌，能够形成生物膜，是一种日益受到临床关注的机会致病菌。Dogma认为生物膜是生长缓慢的结构，通常需要几天才能形成成熟的小菌落。在这里，我们报告，细胞外DNA（eDNA）是一个完整的结构组成部分，早期大肠杆菌。粪肠球菌生物膜（= 24 h）E.在这些条件下，粪肠球菌生物膜似乎不起作用;通过SEM进行的广泛目视检查显示明显缺乏裂解的细胞，并且大量生物化学测定也支持在这些早期时间点不存在显著的裂解。此外，一些细胞表现出eDNA标记定位在隔膜，这表明DNA分泌的可能性，从代谢活跃的细胞。总的来说，这些数据与一个模型是一致的，在该模型中，一个亚群的活大肠杆菌。粪肠球菌细胞分泌或挤出DNA到胞外matrix.IMPORTANCE本文报道了在早期生物膜形成过程中的粪肠球菌胞外DNA的生产。这项工作是重要的，因为eDNA（细胞外DNA）生产的机制是独立的细胞裂解和DNA被限制在明确的结构，这表明一种新的形式的DNA分泌的活细胞。肠球菌和相关物种中生物膜形成的先前模型提出细胞裂解作为DNA释放的机制。
Enterococcus faecalis is a common Gram-positive commensal bacterium of the metazoan gastrointestinal tract capable of biofilm formation and an opportunistic pathogen of increasing clinical concern. Dogma has held that biofilms are slow-growing structures, often taking days to form mature microcolonies. Here we report that extracellular DNA (eDNA) is an integral structural component of early E. faecalis biofilms (= 24 h) E. faecalis biofilms does not appear to be at work under these conditions; extensive visual examination by SEM revealed a striking lack of lysed cells, and bulk biochemical assays also support an absence of significant lysis at these early time points. In addition, some cells demonstrated eDNA labeling localized at the septum, suggesting the possibility of DNA secretion from metabolically active cells. Overall, these data are consistent with a model in which a subpopulation of viable E. faecalis cells secrete or extrude DNA into the extracellular matrix.IMPORTANCE This paper reports the production of extracellular DNA during early biofilm formation in Enterococcus faecalis. The work is significant because the mechanism of eDNA (extracellular DNA) production is independent of cell lysis and the DNA is confined to well-defined structures, suggesting a novel form of DNA secretion by viable cells. Previous models of biofilm formation in enterococci and related species propose cell lysis as the mechanism of DNA release.