Bacterial extracellular vesicles (BEVs) contribute to stress responses, quorum sensing, biofilm formation and interspecies and interkingdom communication. However, the factors that regulate their release and heterogeneity are not well understood. We set out to investigate these factors in the common gut commensal Bacteroides thetaiotaomicron by studying BEV release throughout their growth cycle. Utilising a range of methods, we demonstrate that vesicles released at different stages of growth have significantly different composition, with early vesicles enriched in specifically released outer membrane vesicles (OMVs) containing a larger proportion of lipoproteins, while late phase BEVs primarily contain lytic vesicles with enrichment of cytoplasmic proteins. Furthermore, we demonstrate that lipoproteins containing a negatively charged signal peptide are preferentially incorporated in OMVs. We use this observation to predict all Bacteroides thetaiotaomicron OMV enriched lipoproteins and analyse their function. Overall, our findings highlight the need to understand media composition and BEV release dynamics prior to functional characterisation and define the theoretical functional capacity of Bacteroides thetaiotaomicron OMVs.

中文翻译：

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B. thetaiotaomicron 细菌细胞外囊泡的差异时间释放和脂蛋白负载

细菌细胞外囊泡 (BEV) 有助于应激反应、群体感应、生物膜形成以及种间和界间交流。然而，调节其释放和异质性的因素尚不清楚。我们着手通过研究 BEV 在整个生长周期中的释放来研究常见肠道共生多形拟杆菌中的这些因素。利用一系列方法，我们证明在不同生长阶段释放的囊泡具有显着不同的组成，早期囊泡富含专门释放的外膜囊泡（OMV），其中含有较大比例的脂蛋白，而晚期BEV主要含有溶解性囊泡，细胞质蛋白的富集。此外，我们证明含有带负电荷的信号肽的脂蛋白优先掺入 OMV 中。我们利用这一观察结果来预测所有多形拟杆菌OMV 富集脂蛋白并分析其功能。总体而言，我们的研究结果强调，在功能表征之前需要了解培养基组成和 BEV 释放动态，并定义多形拟杆菌OMV 的理论功能能力。