Physiological and transcriptional approaches reveal connection between nitrogen and manganese cycles in Shewanella algae C6G3.
Physiological and transcriptional approaches reveal connection between nitrogen and manganese cycles in Shewanella algae C6G3.
复制标题
DOI：
10.1038/srep44725
复制
发表时间：
2017-03-20
影响因子：
4.6
通讯作者：
Michotey V
中科院分区：
文献类型：
--
作者：
Aigle A;Bonin P;Iobbi-Nivol C;Méjean V;Michotey V
为了解释以沉积物中氧化锰 (Mn(IV)) 介导的铵为代价的厌氧亚硝酸盐/硝酸盐生产，在具有这些特征的菌株（希瓦氏藻 C6G3）中研究了硝酸盐和锰呼吸。与 S. oneidensis MR-1 相比，在限制电子受体条件下，在 Mn(IV) 厌氧生长期间，在 S. 藻类中观察到以铵为代价的生物短暂亚硝酸盐积累，同时电子供体化学计量比预期更高。这种低且可重复的短暂积累是生产和消耗的结果，因为菌株能够将硝酸盐异化成铵。通过比较硝酸盐/亚硝酸盐还原酶基因（napA、nrfA、nrfA-2）的表达以及 Mn(IV)、硝酸盐或富马酸盐条件下硝酸盐/亚硝酸盐还原酶活性的速率，可以增强 Mn(IV) 条件下的亚硝酸盐生成。与 S. oneidensis MR-1 相比，S. algae 含有编码硝酸盐和亚硝酸盐还原酶（napA-α 和 nrfA-2）以及外膜细胞色素 (OMC)(mtrH) 的额外基因。根据电子受体和生长阶段，观察到 OMC 基因（omcA、mtrF、mtrH 和 mtrC）的不同表达模式。只有基因 mtrF-2（SO1659 同源物）在 Mn(IV) 条件下特异性表达。硝酸盐和锰（IV）呼吸似乎在生理和转录水平上相关。
To explain anaerobic nitrite/nitrate production at the expense of ammonium mediated by manganese oxide (Mn(IV)) in sediment, nitrate and manganese respirations were investigated in a strain (Shewanella algae C6G3) presenting these features. In contrast to S. oneidensis MR-1, a biotic transitory nitrite accumulation at the expense of ammonium was observed in S. algae during anaerobic growth with Mn(IV) under condition of limiting electron acceptor, concomitantly, with a higher electron donor stoichiometry than expected. This low and reproducible transitory accumulation is the result of production and consumption since the strain is able to dissimilative reduce nitrate into ammonium. Nitrite production in Mn(IV) condition is strengthened by comparative expression of the nitrate/nitrite reductase genes (napA, nrfA, nrfA-2), and rates of the nitrate/nitrite reductase activities under Mn(IV), nitrate or fumarate conditions. Compared with S. oneidensis MR-1, S. algae contains additional genes that encode nitrate and nitrite reductases (napA-α and nrfA-2) and an Outer Membrane Cytochrome (OMC)(mtrH). Different patterns of expression of the OMC genes (omcA, mtrF, mtrH and mtrC) were observed depending on the electron acceptor and growth phase. Only gene mtrF-2 (SO1659 homolog) was specifically expressed under the Mn(IV) condition. Nitrate and Mn(IV) respirations seem connected at the physiological and transcriptional levels.