The ithree institute, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
National Heart and Lung Institute, Imperial College London, London, SW3 6LR, UK.
Microbiology (Reading). 2021 Apr;167(4). doi: 10.1099/mic.0.001021.
Membrane vesicles (MVs) are membrane-bound spherical nanostructures that prevail in all three domains of life. In Gram-negative bacteria, MVs are thought to be produced through blebbing of the outer membrane and are often referred to as outer membrane vesicles (OMVs). We have recently described another mechanism of MV formation in that involves explosive cell-lysis events, which shatters cellular membranes into fragments that rapidly anneal into MVs. Interestingly, MVs are often observed within preparations of lytic bacteriophage, however the source of these MVs and their association with bacteriophage infection has not been explored. In this study we aimed to determine if MV formation is associated with lytic bacteriophage infection. Live super-resolution microscopy demonstrated that explosive cell lysis of cells infected with either bacteriophage T4 or T7, resulted in the formation of MVs derived from shattered membrane fragments. Infection by either bacteriophage was also associated with the formation of membrane blebs on intact bacteria. TEM revealed multiple classes of MVs within phage lysates, consistent with multiple mechanisms of MV formation. These findings suggest that bacteriophage infection may be a major contributor to the abundance of bacterial MVs in nature.
膜泡（MVs）是一种普遍存在于生命三大领域的膜结合球形纳米结构。在革兰氏阴性细菌中，MVs 被认为是通过外膜的起泡而产生的，通常被称为外膜囊泡（OMVs）。我们最近在 中描述了另一种 MV 形成机制，该机制涉及细胞的爆炸性裂解事件，会将细胞膜破碎成碎片，这些碎片迅速融合形成 MV。有趣的是，MVs 经常在裂解噬菌体的制备物中观察到，然而，这些 MV 的来源及其与噬菌体感染的关联尚未得到探索。在这项研究中，我们旨在确定 MV 的形成是否与裂解噬菌体感染有关。活超分辨率显微镜显示，感染噬菌体 T4 或 T7 的 细胞的爆炸性细胞裂解导致源自破碎膜片段的 MV 的形成。两种噬菌体的感染也与完整细菌上膜泡的形成有关。TEM 揭示了噬菌体裂解物中的多种 MV 类别，与 MV 形成的多种机制一致。这些发现表明，噬菌体感染可能是自然界中细菌 MV 丰度的主要贡献者。
