Response of heterotrophic bacteria in a mesoscale iron enrichment in the northeast subarctic Pacific Ocean
Response of heterotrophic bacteria in a mesoscale iron enrichment in the northeast subarctic Pacific Ocean
复制标题
亚北极东北太平洋中尺度铁富集中异养细菌的响应
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
N. M. Price
中科院分区：
文献类型：
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作者：
Carol. Adly;J. Tremblay;R. T. Powell;E. Armstrong;Graham Peers;N. M. Price
2002年7月，在亚北极太平洋东北部海域观测了异养细菌对中尺度铁（Fe）富集的响应。添加FeSO 4使受精斑中溶解的Fe浓度增加到2-3 nmol L−1，并引发Fe（III）结合配体的浓度增加，这些配体与所有溶解的Fe络合。两到三天后，细菌的亮氨酸掺入率和比生长率翻了一番。细菌铁营养状态的生理指标在实验过程中随着微生物群落对铁的吸收而变化。铁-铁载体复合物55 Fe-亚铁胺B（FB）的细胞摄取率比背景值增加2 - 4倍，然后在第4.5天下降。第2.5天Fe-FB摄取的最快速率大致与细菌外膜55 Fe-FB结合蛋白的瞬时增加和配体浓度的峰值一致。无机铁的最大潜在吸收速率（Vmax）在铁富集之前为8 zmol Fe细菌−1 h−1，然后在接种补丁的2.5 d内下降了4倍，因为细菌变得足够铁。随着细菌群落重新进入缺铁状态，Vmax在第6.5天逐渐增加。在第二次Fe添加后观察到生长和Fe吸收动力学的类似变化。亚北极太平洋的异养细菌缺乏Fe，并通过上调Fe-铁载体获取和同化络合Fe的途径直接响应Fe的添加。铁的吸收途径和生产同步增加的观察结果与细菌生长直接受铁限制的假设一致。
The response of heterotrophic bacteria in a mesoscale iron (Fe) enrichment was measured in the northeast subarctic Pacific Ocean in July 2002. Addition of FeSO4 increased the dissolved Fe concentration in the fertilized patch to 2–3 nmol L−1 and triggered an increase in concentration of Fe(III)‐binding ligands that complexed all of the dissolved Fe. Two to three days later, leucine incorporation rate and specific growth rate of bacteria doubled. Physiological markers of bacterial Fe nutritional state varied during the experiment as the microbial community assimilated the added Fe. Cellular uptake rate of an iron‐siderophore complex, 55Fe‐ferrioxamine B (FB), increased twofold to fourfold over background values and then declined by day 4.5. The fastest rate of Fe‐FB uptake on day 2.5 coincided roughly with a transient increase in outer‐membrane, 55Fe‐FB‐binding protein(s) in bacteria and with the peak in ligand concentration. Maximum potential uptake rate of inorganic Fe (Vmax) was 8 zmol Fe bacterium−1 h−1 prior to Fe enrichment and then decreased by a factor of four within 2.5 d of fertilizing the patch as bacteria became Fe sufficient. Vmax gradually increased by day 6.5 as the bacterial community re‐entered iron deficiency. Similar changes in growth and Fe uptake kinetics were observed after a second Fe addition. Heterotrophic bacteria in the subarctic Pacific were Fe‐deficient and responded directly to Fe addition by up‐regulating pathways for Fe‐siderophore acquisition and assimilating complexed Fe. The observation that increases in Fe uptake pathways and production were synchronous is consistent with the hypothesis that bacterial growth was directly limited by Fe.
DOI：
10.1073/pnas.200318797
发表时间：
2000-09-26
影响因子：
11.1
作者：
Stintzi, A;Barnes, C;Raymond, KN
通讯作者：
Raymond, KN