Abstract

Extracellular DNA (eDNA) is a macromolecule copiously found in various natural microenvironments, but its origin and significance still remain partly mysterious phenomena. Here, the multifaceted origins of eDNA in bacterial biofilms are explored. The release of eDNA can follow a suicidal programmed bacterial apoptosis or a fratricide-induced death, under the control of quorum sensing systems or triggered by specific stressors. eDNA can be released into the extracellular space or as a free macromolecule or enclosed within membrane vesicles or even through an explosion of bubbles. eDNA can also be derived from host tissue cells through bacterial cytolytic/proapoptotic toxins or stolen from neutrophil extracellular traps (NETs). eDNA can alternatively be produced by lysis-independent mechanisms. Sub-inhibitory doses of antibiotics, by killing a fraction of bacteria, result in stimulating the release of eDNA. Even phages appear to play a role in favoring eDNA release. Unveiling the origins of eDNA is critical to correctly address biofilm-associated infections.

摘要

细胞外 DNA (eDNA) 是一种在各种自然微环境中大量发现的大分子，但它的起源和意义仍然是部分神秘的现象。在这里，探索了细菌生物膜中 eDNA 的多方面起源。在群体感应系统的控制下或由特定压力源触发时，eDNA 的释放可以遵循自杀性程序性细菌凋亡或自相残杀诱导的死亡。eDNA 可以释放到细胞外空间或作为游离大分子或封闭在膜囊泡内，甚至通过气泡爆炸。eDNA 也可以通过细菌溶细胞/促凋亡毒素从宿主组织细胞中获得，或者从中性粒细胞胞外陷阱 (NET) 中窃取。eDNA 也可以通过不依赖裂解的机制产生。亚抑制剂量的抗生素，通过杀死一小部分细菌，导致刺激 eDNA 的释放。甚至噬菌体似乎也在促进 eDNA 释放方面发挥作用。揭示 eDNA 的起源对于正确解决生物膜相关感染至关重要。