Quantifying population-specific growth in benthic bacterial communities under low oxygen using H218O
Quantifying population-specific growth in benthic bacterial communities under low oxygen using H218O
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DOI：
10.1038/s41396-019-0373-4
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发表时间：
2019-06-01
期刊：
影响因子：
11
通讯作者：
Orsi, William D.
中科院分区：
文献类型：
--
作者：
Coskun, Oemer K.;Oezen, Volkan;Orsi, William D.
河口环境中的底栖生物经常经历定期发生的缺氧和缺氧条件，显着影响生态地球化学循环。然而，氧气消耗如何影响这些不同的底栖生物群落中特定的未培养微生物种群的生长，仍然知之甚少。在这里，我们应用（H2O）-O-18定量稳定同位素探测（qSIP），以量化的增长，不同的，未培养的细菌种群在河口沉积物中的低氧浓度。在7-和28天的培养过程中，氧化还原条件从缺氧到euxinia（硫化物），O-18标记的细菌种群表现出不同的模式符合微需氧，厌氧，兼性厌氧，耐氧厌氧生长。O-18标记的群体显示厌氧生长有一个显着的非随机系统发育分布，表现出许多分支目前缺乏培养的代表内的浮游菌，放线菌，Latescibacteria，疣微菌，和酸杆菌。编码异化硫酸还原酶（dsrB）的β-亚基的基因仅在缺氧条件下被O-18标记。这些O-18-标记的dsrB基因的测序结果表明，酸杆菌是生长的硫酸盐还原菌的优势群体，突出了它们在河口沉积物中的硫循环的重要性。我们的研究结果提供了第一个实验限制的氧化还原条件下增加增长的几组“微生物暗物质”，验证了早期宏基因组研究提出的假设。
The benthos in estuarine environments often experiences periods of regularly occurring hypoxic and anoxic conditions, dramatically impacting biogeochemical cycles. How oxygen depletion affects the growth of specific uncultivated microbial populations within these diverse benthic communities, however, remains poorly understood. Here, we applied (H2O)-O-18 quantitative stable isotope probing (qSIP) in order to quantify the growth of diverse, uncultured bacterial populations in response to low oxygen concentrations in estuarine sediments. Over the course of 7- and 28-day incubations with redox conditions spanning from hypoxia to euxinia (sulfidic), O-18 labeling of bacterial populations exhibited different patterns consistent with micro-aerophilic, anaerobic, facultative anaerobic, and aerotolerant anaerobic growth. O-18-labeled populations displaying anaerobic growth had a significantly non-random phylogenetic distribution, exhibited by numerous clades currently lacking cultured representatives within the Planctomycetes, Actinobacteria, Latescibacteria, Verrucomicrobia, and Acidobacteria. Genes encoding the beta-subunit of the dissimilatory sulfate reductase (dsrB) became O-18 labeled only during euxinic conditions. Sequencing of these O-18-labeled dsrB genes showed that Acidobacteria were the dominant group of growing sulfate-reducing bacteria, highlighting their importance for sulfur cycling in estuarine sediments. Our findings provide the first experimental constraints on the redox conditions underlying increased growth in several groups of "microbial dark matter", validating hypotheses put forth by earlier metagenomic studies.