Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Department of Biological Sciences, Wellesley College, Wellesley, Massachusetts, USA.
Appl Environ Microbiol. 2023 Jun 28;89(6):e0059423. doi: 10.1128/aem.00594-23. Epub 2023 May 18.
Extracellular vesicles are small (approximately 50 to 250 nm in diameter), membrane-bound structures that are released by cells into their surrounding environment. Heterogeneous populations of vesicles are abundant in the global oceans, and they likely play a number of ecological roles in these microbially dominated ecosystems. Here, we examine how vesicle production and size vary among different strains of cultivated marine microbes as well as explore the degree to which this is influenced by key environmental variables. We show that both vesicle production rates and vesicle sizes significantly differ among cultures of marine Proteobacteria, Cyanobacteria, and Bacteroidetes. Further, these properties vary within individual strains as a function of differences in environmental conditions, such as nutrients, temperature, and light irradiance. Thus, both community composition and the local abiotic environment are expected to modulate the production and standing stock of vesicles in the oceans. Examining samples from the oligotrophic North Pacific Gyre, we show depth-dependent changes in the abundance of vesicle-like particles in the upper water column in a manner that is broadly consistent with culture observations: the highest vesicle abundances are found near the surface, where the light irradiances and the temperatures are the greatest, and they then decrease with depth. This work represents the beginnings of a quantitative framework for describing extracellular vesicle dynamics in the oceans, which is essential as we begin to incorporate vesicles into our ecological and biogeochemical understanding of marine ecosystems. Bacteria release extracellular vesicles that contain a wide variety of cellular compounds, including lipids, proteins, nucleic acids, and small molecules, into their surrounding environment. These structures are found in diverse microbial habitats, including the oceans, where their distributions vary throughout the water column and likely affect their functional impacts within microbial ecosystems. Using a quantitative analysis of marine microbial cultures, we show that bacterial vesicle production in the oceans is shaped by a combination of biotic and abiotic factors. Different marine taxa release vesicles at rates that vary across an order of magnitude, and vesicle production changes dynamically as a function of environmental conditions. These findings represent a step forward in our understanding of bacterial extracellular vesicle production dynamics and provide a basis for the quantitative exploration of the factors that shape vesicle dynamics in natural ecosystems.
细胞外囊泡是直径约 50 至 250nm 的小的、膜结合的结构，由细胞释放到其周围环境中。异质的囊泡群体在全球海洋中丰富存在，它们可能在这些微生物主导的生态系统中发挥多种生态作用。在这里，我们研究了不同培养海洋微生物菌株的囊泡产生和大小如何变化，并探索了这些变化受关键环境变量影响的程度。我们表明，海洋变形菌、蓝细菌和拟杆菌的培养物的囊泡产生率和囊泡大小都有显著差异。此外，这些特性在单个菌株内作为环境条件差异的函数而变化，例如营养物质、温度和光照辐照度。因此，群落组成和局部非生物环境预计将调节海洋中囊泡的产生和存量。在考察贫营养的北太平洋 Gyre 的样本时，我们以与培养观察大致一致的方式显示了上水柱中类似囊泡颗粒的丰度随深度的变化：在光照辐照度和温度最大的表面附近，囊泡丰度最高，然后随深度降低。这项工作代表了描述海洋中细胞外囊泡动力学的定量框架的开始，这对于我们开始将囊泡纳入对海洋生态系统的生态和生物地球化学理解中是必不可少的。
细菌将包含各种细胞化合物的细胞外囊泡（包括脂质、蛋白质、核酸和小分子）释放到其周围环境中。这些结构存在于各种微生物生境中，包括海洋，它们在水柱中的分布不同，并且可能对其在微生物生态系统中的功能影响。通过对海洋微生物培养物的定量分析，我们表明，海洋中细菌囊泡的产生是由生物和非生物因素共同塑造的。不同的海洋分类群以跨越一个数量级的速率释放囊泡，并且囊泡的产生会随着环境条件的动态变化而变化。这些发现代表了我们对细菌细胞外囊泡产生动力学的理解的一个进步，并为定量探索塑造自然生态系统中囊泡动力学的因素提供了基础。
