Bacterial nitrate assimilation: gene distribution and regulation
Bacterial nitrate assimilation: gene distribution and regulation
复制标题
DOI：
10.1042/bst20110688
复制
发表时间：
2011-12-01
影响因子：
3.9
通讯作者：
Dolores Roldan, M.
中科院分区：
文献类型：
--
作者：
Luque-Almagro, Victor M.;Gates, Andrew J.;Dolores Roldan, M.
在全球氮循环的背景下，无机硝酸盐对海洋和淡水自养浮游植物的营养和生长的重要性早已被认识到。相比之下，硝酸盐的异养细菌的利用历来受到较少的关注，因为这些生物的主要作用一直被认为是传统的溶解和颗粒有机氮的分解和矿化。在前基因组测序时代，人们知道一些但不是所有的异养细菌能够在硝酸盐作为唯一氮源上生长。然而，目前可用的原核基因组序列的检查表明，同化硝酸还原酶（Nas）系统广泛存在于细菌和古菌异养生物中。到目前为止，硝酸盐同化的调控主要是在蓝藻中进行研究。相反，在异养细菌菌株中，硝酸盐同化调节的研究仅限于Rhodobacter capsulatus、Klebsiello oxytoca、Azotobacter yinelandii和Bacillus subtilis。在革兰氏阴性菌中，nos基因受到双重控制：一般氮调节（Ntr）系统的氨抑制和特定的硝酸盐或亚硝酸盐诱导。Ntr系统广泛分布于细菌中，而硝酸盐/亚硝酸盐特异性控制则因生物体而异。
In the context of the global nitrogen cycle, the importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognized. In contrast, the utilization of nitrate by heterotrophic bacteria has historically received less attention because the primary role of these organisms has classically been considered to be the decomposition and mineralization of dissolved and particulate organic nitrogen. In the pre-genome sequence era, it was known that some, but not all, heterotrophic bacteria were capable of growth on nitrate as a sole nitrogen source. However, examination of currently available prokaryotic genome sequences suggests that assimilatory nitrate reductase (Nas) systems are widespread phylogenetically in bacterial and archaeal heterotrophs. Until now, regulation of nitrate assimilation has been mainly studied in cyanobacteria. In contrast, in heterotrophic bacterial strains, the study of nitrate assimilation regulation has been limited to Rhodobacter capsulatus, Klebsiello oxytoca, Azotobacter yinelandii and Bacillus subtilis. In Gram-negative bacteria, the nos genes are subjected to dual control: ammonia repression by the general nitrogen regulatory (Ntr) system and specific nitrate or nitrite induction. The Ntr system is widely distributed in bacteria, whereas the nitrate/nitrite-specific control is variable depending on the organism.