University of Southern Californiagrid.42505.36, Department of Biological Sciences, Los Angeles, California, USA.
University of Southern Californiagrid.42505.36, Department of Physics and Astronomy, Los Angeles, California, USA.
Appl Environ Microbiol. 2022 Dec 13;88(23):e0134622. doi: 10.1128/aem.01346-22. Epub 2022 Nov 7.
The exchange of bacterial extracellular vesicles facilitates molecular exchange between cells, including the horizontal transfer of genetic material. Given the implications of such transfer events on cell physiology and adaptation, some bacterial cells have likely evolved mechanisms to regulate vesicle exchange. Past work has identified mechanisms that influence the formation of extracellular vesicles, including the production of small molecules that modulate membrane structure; however, whether these mechanisms also modulate vesicle uptake and have an overall impact on the rate of vesicle exchange is unknown. Here, we show that membrane-binding molecules produced by microbes influence both the formation and uptake of extracellular vesicles and have the overall impact of increasing the vesicle exchange rate within a bacterial coculture. In effect, production of compounds that increase vesicle exchange rates encourage gene exchange between neighboring cells. The ability of several membrane-binding compounds to increase vesicle exchange was demonstrated. Three of these compounds, nisin, colistin, and polymyxin B, are antimicrobial peptides added at sub-inhibitory concentrations. These results suggest that a potential function of exogenous compounds that bind to membranes may be the regulation of vesicle exchange between cells. The exchange of bacterial extracellular vesicles is one route of gene transfer between bacteria, although it was unclear if bacteria developed strategies to modulate the rate of gene transfer within vesicles. In eukaryotes, there are many examples of specialized molecules that have evolved to facilitate the production, loading, and uptake of vesicles. Recent work with bacteria has shown that some small molecules influence membrane curvature and induce vesicle formation. Here, we show that similar compounds facilitate vesicle uptake, thereby increasing the overall rate of vesicle exchange within bacterial populations. The addition of membrane-binding compounds, several of them antibiotics at subinhibitory concentrations, to a bacterial coculture increased the rate of horizontal gene transfer via vesicle exchange.
细菌细胞外囊泡的交换促进了细胞间的分子交换，包括遗传物质的水平转移。鉴于这种转移事件对细胞生理和适应的影响，一些细菌细胞可能已经进化出了调节囊泡交换的机制。过去的工作已经确定了影响细胞外囊泡形成的机制，包括产生调节膜结构的小分子；然而，这些机制是否也调节囊泡摄取，并对囊泡交换率产生整体影响尚不清楚。在这里，我们表明微生物产生的膜结合分子影响细胞外囊泡的形成和摄取，并对细菌共培养物中囊泡交换率的整体增加产生影响。实际上，增加囊泡交换率的化合物的产生鼓励了相邻细胞之间的基因交换。几种膜结合化合物增加囊泡交换的能力得到了证明。这三种化合物，乳链菌肽、黏菌素和多粘菌素 B，是在亚抑菌浓度下添加的抗菌肽。这些结果表明，与膜结合的外源化合物的潜在功能可能是调节细胞间囊泡交换。细菌细胞外囊泡的交换是细菌之间基因转移的一种途径，尽管尚不清楚细菌是否制定了策略来调节囊泡内基因转移的速度。在真核生物中，有许多专门的分子进化来促进囊泡的产生、装载和摄取。最近对细菌的研究表明，一些小分子会影响膜曲率并诱导囊泡形成。在这里，我们表明，类似的化合物促进囊泡摄取，从而增加细菌群体中囊泡交换的整体速率。向细菌共培养物中添加膜结合化合物，其中一些在亚抑菌浓度下是抗生素，可以增加通过囊泡交换的水平基因转移率。
