Extracellular vesicles are small (~50–200 nm diameter) membrane-bound structures released by cells from all domains of life. While vesicles are abundant in the oceans, their functions, both for cells themselves and the emergent ecosystem, remain a mystery. To better characterize these particles – a prerequisite for determining function – we analysed the lipid, protein, and metabolite content of vesicles produced by the marine cyanobacterium Prochlorococcus. We show that Prochlorococcus exports a diverse array of cellular compounds into the surrounding seawater enclosed within discrete vesicles. Vesicles produced by two different strains contain some materials in common, but also display numerous strain-specific differences, reflecting functional complexity within vesicle populations. The vesicles contain active enzymes, indicating that they can mediate extracellular biogeochemical reactions in the ocean. We further demonstrate that vesicles from Prochlorococcus and other bacteria associate with diverse microbes including the most abundant marine bacterium, Pelagibacter. Together, our data point toward hypotheses concerning the functional roles of vesicles in marine ecosystems including, but not limited to, possibly mediating energy and nutrient transfers, catalysing extracellular biochemical reactions, and mitigating toxicity of reactive oxygen species.

中文翻译：

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原绿球藻细胞外囊泡：分子组成和对不同微生物的吸附

细胞外囊泡是由所有生命领域的细胞释放的小的（约 50-200 nm 直径）膜结合结构。虽然海洋中的囊泡很丰富，但它们对细胞本身和新兴生态系统的功能仍然是一个谜。为了更好地表征这些颗粒 - 确定功能的先决条件 - 我们分析了海洋蓝藻Prochlorococcus产生的囊泡的脂质、蛋白质和代谢物含量。我们证明了Prochlorococcus将多种细胞化合物输出到包围在离散囊泡中的周围海水中。由两种不同菌株产生的囊泡含有一些共同的材料，但也显示出许多菌株特异性差异，反映了囊泡群体内的功能复杂性。囊泡含有活性酶，表明它们可以介导海洋中的细胞外生物地球化学反应。我们进一步证明了来自Prochlorococcus和其他细菌的囊泡与多种微生物相关，包括最丰富的海洋细菌Pelagibacter. 总之，我们的数据指向关于囊泡在海洋生态系统中的功能作用的假设，包括但不限于可能介导能量和养分转移、催化细胞外生化反应和减轻活性氧的毒性。