H2 accumulation and N2 fixation variation by Ni limitation in Cyanothece
H2 accumulation and N2 fixation variation by Ni limitation in Cyanothece
复制标题
Cyanothece 中 Ni 限制导致的 H2 积累和 N2 固定变化
作者：
Sing‐how Tuo;I. Rodriguez;T. Ho
镍是NiFe -摄取氢化酶的重要辅助因子，NiFe -摄取氢化酶是重氮营养蓝藻中调节H2代谢的酶，重氮营养蓝藻是全球海洋表面主要的H2产生菌。本文以重氮营养型蓝藻蓝藻（Cyanothece）为研究对象，研究了Ni供给对H2生成和N2固定的影响。通过在微量金属定义的培养基中调节总溶解Ni浓度从100到0.03 nmol L−1，我们证明了Ni缺乏会导致H2积累，同时伴随着Ni配额和生长速率的降低，以及偶尔相对较低的N2固定率。这些结果表明，缺镍在一定程度上限制了蓝藻的生长，显著降低了加氢酶对H2的吸收，导致重氮营养体中H2积累和N2固定发生变化。结果表明，Ni的有效性是控制重氮营养蓝藻产氢和固氮的关键因素。因此，重氮营养蓝藻的Ni生物利用度信息对于评估Ni对海洋表层水H2循环和N2固定的重要性至关重要。
Ni is an essential cofactor in NiFe‐uptake hydrogenase, an enzyme regulating H2 metabolism in diazotrophic cyanobacteria, the major H2 producers in the surface ocean globally. Here, we investigated the effect of Ni supply on H2 production and N2 fixation by using a model marine cyanobacterial diazotroph, Cyanothece. By mediating total dissolved Ni concentrations from 100 to 0.03 nmol L−1 in a trace metal‐defined culture medium, we demonstrated that Ni deficiency results in H2 accumulation, coupled with decreasing Ni quotas, growth rates, and occasionally relatively low N2 fixation rates. These results indicate that Ni deficiency limits the growth of the Cyanothece to some extent, considerably decreases H2 uptake by hydrogenase and leads to H2 accumulation and N2 fixation variation in the diazotroph. The findings show that Ni availability is a critical factor on controlling H2 production and N2 fixation in marine diazotrophic cyanobacteria. The information of Ni bioavailability for diazotrophic cyanobacteria is thus essential to evaluate the importance of Ni for H2 cycling and N2 fixation in oceanic surface waters.
影响因子：
11.4
作者：
Luo, Y. -W.;Doney, S. C.;Zehr, J. P.
通讯作者：
Zehr, J. P.