High bicarbonate assimilation in the dark by Arctic bacteria
High bicarbonate assimilation in the dark by Arctic bacteria
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DOI：
10.1038/ismej.2010.69
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发表时间：
2010-12-01
期刊：
影响因子：
11
通讯作者：
Bertilsson, Stefan
中科院分区：
文献类型：
--
作者：
Alonso-Saez, Laura;Galand, Pierre E.;Bertilsson, Stefan
虽然自养和异养微生物都通过不同的代谢途径在黑暗中吸收CO（2），但这一过程在好氧海洋环境中通常被忽视。我们研究了冬季北极海水接种的稀释培养物中暗碳酸氢盐同化的意义和介质。在稳定期，碳酸氢根掺入率很高（0.5-2.5 μ gC L（-1）d（-1）），并与细菌异养生产率相关，表明大部分掺入是由于异养生物。因此，通过16 S rRNA基因克隆检测到非常少的典型化能自养细菌。对参与古细菌CO（2）固定作用的生物素羧化酶基因accC puericum的遗传分析没有得到任何古细菌序列，但扩增了多种参与脂肪酸生物合成、回补途径和亮氨酸催化剂的细菌羧化酶。γ-变形菌占主导地位的海水培养（40-70%的细胞计数），其次是β-变形菌和黄细菌，如催化报告沉积荧光原位杂交（CARDFISH）所示。β-和γ-变形菌活跃的亮氨酸和碳酸氢盐的吸收，而黄细菌不采取碳酸氢盐，结合CARDFISH的microautoradiography测量。在γ-变形菌中，假交替单胞菌-科尔韦利亚菌和油旋菌在碳酸氢盐吸收方面非常活跃（约100 mg/L）。30%和70%的活性细胞），而Arctic 96 B-16组不摄取碳酸氢盐。我们的研究结果表明，潜在的，CO（2）的掺入可能与特定的北极异养藻类的代谢有关，促进其细胞活性的维持和/或在资源枯竭的条件下更长的生存期。The ISME Journal（2010）4，1581-1590; doi：10.1038/ismej. 2010.69; 2010年6月17日在线发布
Although both autotrophic and heterotrophic microorganisms incorporate CO(2) in the dark through different metabolic pathways, this process has usually been disregarded in oxic marine environments. We studied the significance and mediators of dark bicarbonate assimilation in dilution cultures inoculated with winter Arctic seawater. At stationary phase, bicarbonate incorporation rates were high (0.5-2.5 mu gC L(-1) d(-1)) and correlated with rates of bacterial heterotrophic production, suggesting that most of the incorporation was due to heterotrophs. Accordingly, very few typically chemoautotrophic bacteria were detected by 16S rRNA gene cloning. The genetic analysis of the biotin carboxylase gene accC putatively involved in archaeal CO(2) fixation did not yield any archaeal sequence, but amplified a variety of bacterial carboxylases involved in fatty acids biosynthesis, anaplerotic pathways and leucine catabolism. Gammaproteobacteria dominated the seawater cultures (40-70% of cell counts), followed by Betaproteobacteria and Flavobacteria as shown by catalyzed reporter deposition fluorescence in situ hybridization (CARDFISH). Both Beta-and Gammaproteobacteria were active in leucine and bicarbonate uptake, while Flavobacteria did not take up bicarbonate, as measured by microautoradiography combined with CARDFISH. Within Gammaproteobacteria, Pseudoalteromonas-Colwellia and Oleispira were very active in bicarbonate uptake (ca. 30 and 70% of active cells, respectively), while the group Arctic96B-16 did not take up bicarbonate. Our results suggest that, potentially, the incorporation of CO(2) can be relevant for the metabolism of specific Arctic heterotrophic phylotypes, promoting the maintenance of their cell activity and/or longer survival under resource depleted conditions. The ISME Journal (2010) 4, 1581-1590; doi: 10.1038/ismej. 2010.69; published online 17 June 2010