Peng Ziqing, Liu Yaxin, Ma Haiying, Xiao Shiwei, Au-Yeung Allan, Zhang Liang, Zeng Qinglu, Guo Yusong
Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China.
Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China.
Philos Trans R Soc Lond B Biol Sci. 2025 Jan 23;380(1918):20230339. doi: 10.1098/rstb.2023.0339.
Bacterial extracellular vesicles (EVs) are vesicles secreted by bacteria into the extracellular environment. Containing DNA, RNA and proteins, EVs are implicated to mediate intercellular communications. The marine cyanobacterium , the most abundant photosynthetic organism in marine ecosystems, has been shown to generate EVs continuously during cell growth. However, biogenesis and functions of EVs released by remain largely unclear. Here, we isolated and characterized EVs released by MED4 culture. We found that the majority of MED4 EVs are elliptical and enriched with specific proteins performing particular cellular functions. The light-dark cycle has been demonstrated to affect the cell cycle of , with cell division occurring at night time. Interestingly, we found that the net production of MED4 EVs was faster during the night time. Moreover, we revealed that MED4 EVs that are released or absorbed in the night time are enriched with distinct proteins, suggesting the release and absorbance of EVs are influenced by the diel cycle. We found that inhibiting cell division decreased the net production of MED4 EVs during the night time, suggesting that cell division is important for the biogenesis of MED4 EVs. These analyses provide novel insights into biogenesis and functions of EVs released from bacteria.This article is part of the Theo Murphy meeting issue 'Circadian rhythms in infection and immunity'.
细菌细胞外囊泡（EVs）是细菌分泌到细胞外环境中的囊泡。EVs含有DNA、RNA和蛋白质，被认为介导细胞间通讯。海洋蓝细菌是海洋生态系统中最丰富的光合生物，已证明其在细胞生长过程中持续产生EVs。然而， 释放的EVs的生物发生和功能在很大程度上仍不清楚。在这里，我们分离并鉴定了MED4培养物释放的EVs。我们发现，大多数MED4 EVs是椭圆形的，富含执行特定细胞功能的特定蛋白质。明暗循环已被证明会影响 的细胞周期，细胞分裂发生在夜间。有趣的是，我们发现MED4 EVs的净产量在夜间更快。此外，我们发现夜间释放或吸收的MED4 EVs富含不同的蛋白质，这表明EVs的释放和吸收受昼夜循环影响。我们发现抑制细胞分裂会降低夜间MED4 EVs的净产量，这表明细胞分裂对MED4 EVs的生物发生很重要。这些分析为细菌释放的EVs的生物发生和功能提供了新的见解。本文是西奥·墨菲会议特刊“感染与免疫中的昼夜节律”的一部分。
