Extracellular superoxide production by key microbes in the global ocean
Extracellular superoxide production by key microbes in the global ocean
复制标题
DOI：
10.1002/lno.11247
复制
发表时间：
2019-07-10
影响因子：
4.5
通讯作者：
Hansel, Colleen M.
中科院分区：
文献类型：
--
作者：
Sutherland, Kevin M.;Coe, Allison;Hansel, Colleen M.
细菌和真核生物在细胞内外都会产生活性氧物种超氧化物。虽然超氧化物通常与氧化应激的有害影响有关，有时甚至是致命的，但它也被证明参与了一系列基本的生化过程，包括细胞信号、生长、分化和防御。光不依赖细胞外超氧化物的产生在许多海洋异养生物和浮游植物中广泛存在，但这一特征与全球海洋微生物生理和生态的关系尚不清楚。在这里，我们调查了五组生物的黑暗细胞外超氧化物的产生，这五组生物在地理上分布广泛，代表了全球海洋中一些最丰富的生物。这些细菌包括原氯球菌属、聚球菌属、Pelagibacter属、棕囊藻属和双歧杆菌属。细胞归一化细胞外超氧物净产生率为7个数量级，从检测不到到14,830amol cell(-1)h(-1)，蓝藻原氯球菌产氧量最低，隐芽双子藻产氧量最多。细胞外超氧化物的产生与细胞数量呈强烈的负相关，这表明在细胞信号转导中具有潜在的作用。我们证明，聚球藻和巴氏杆菌的净超氧化物产生率的快速、依赖于细胞数量的变化主要源于细胞外超氧化物总产量的变化，而不是衰变。这些结果扩大了黑暗细胞外超氧化物产生与全球海洋关键海洋微生物的相关性，表明海洋水域中超氧化物的产生受到黑暗和阳光下水域各种海洋生物的调节。
Bacteria and eukaryotes produce the reactive oxygen species superoxide both within and outside the cell. Although superoxide is typically associated with the detrimental and sometimes fatal effects of oxidative stress, it has also been shown to be involved in a range of essential biochemical processes, including cell signaling, growth, differentiation, and defense. Light-independent extracellular superoxide production has been shown to be widespread among many marine heterotrophs and phytoplankton, but the extent to which this trait is relevant to marine microbial physiology and ecology throughout the global ocean is unknown. Here, we investigate the dark extracellular superoxide production of five groups of organisms that are geographically widespread and represent some of the most abundant organisms in the global ocean. These include Prochlorococcus, Synechococcus, Pelagibacter, Phaeocystis, and Geminigera. Cell-normalized net extracellular superoxide production rates ranged seven orders of magnitude, from undetectable to 14,830 amol cell(-1) h(-1), with the cyanobacterium Prochlorococcus being the lowest producer and the cryptophyte Geminigera being the most prolific producer. Extracellular superoxide production exhibited a strong inverse relationship with cell number, pointing to a potential role in cell signaling. We demonstrate that rapid, cell-number-dependent changes in the net superoxide production rate by Synechococcus and Pelagibacter arose primarily from changes in gross production of extracellular superoxide, not decay. These results expand the relevance of dark extracellular superoxide production to key marine microbes of the global ocean, suggesting that superoxide production in marine waters is regulated by a diverse suite of marine organisms in both dark and sunlit waters.