Survival of Prochlorococcus in extended darkness
Survival of Prochlorococcus in extended darkness
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DOI：
10.1002/lno.10302
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发表时间：
2016-07-01
影响因子：
4.5
通讯作者：
Chisholm, Sallie W.
中科院分区：
文献类型：
--
作者：
Coe, Allison;Ghizzoni, Julie;Chisholm, Sallie W.
原绿球藻是海洋中最小的产氧光养生物，在中纬度沃茨的真光层中大量存在。在真光层以下已经观察到这种微蓝细菌的种群，但这些细胞的活力尚不清楚。为了探索原绿球藻对延长的光剥夺的耐受性，我们将多株原绿球藻置于不同的黑暗时间，并检查它们在放回光照下时的恢复能力。一些菌株恢复后35小时的黑暗，而其他人不能，这种变异性是不相关的菌株是否是高或低光适应生态型的成员。海洋异养菌Alteromonas macleodii MIT1002的存在，在文化中延长了他们的生存能力，延长黑暗，在最极端的情况下，11天。这可以至少部分地归因于共培养物中过氧化氢的减少，这与“辅助细菌”在过氧化氢解毒中的已知作用一致，并且这种作用可以通过添加已知的过氧化氢猝灭剂丙酮酸钠在一定程度上模拟。单独向培养物中添加葡萄糖提供了边际增强，但是当丙酮酸盐和葡萄糖一起添加时，所有菌株都能够在黑暗中存活更长时间，而不是仅添加异养菌。因此，原绿球藻的暗生存似乎取决于多种因素。对聚球藻的有限分析表明，其黑暗生存能力比原绿球藻长，原因尚不清楚。
Prochlorococcus is the smallest oxygenic phototroph in the ocean, where it can be found in great abundance throughout the euphotic zone in mid-latitude waters. Populations of this picocyanobacterium have been observed below the euphotic zone, but the viability of these cells is unclear. To explore the tolerance of Prochlorococcus to extended light-deprivation, we subjected multiple strains of Prochlorococcus to varying periods of darkness and examined their ability to recover when placed back in the light. Some strains recovered after 35 h of darkness while others could not; this variability was not related to whether the strains were members of high-or low-light adapted ecotypes. The presence of a marine heterotroph, Alteromonas macleodii MIT1002, in the cultures extended their ability to survive prolonged darkness, in the most extreme case by 11 d. This could be attributed at least in part to the reduction of hydrogen peroxide in co-cultures, consistent with known roles of "helper bacteria" in detoxifying hydrogen peroxide, and this effect could be mimicked to some degree by the addition of a known hydrogen peroxide quencher, sodium pyruvate. The addition of glucose alone to the cultures provided marginal enhancement, but when both pyruvate and glucose were added together, all strains were able to survive longer in darkness than they were with only the heterotroph added. Thus, it appears that Prochlorococcus dark-survival depends on a multitude of factors. Limited analyses of Synechococcus suggest that its dark-survival capacity is longer than that of Prochlorococcus, for reasons that are not yet clear.