Linkage of the Nit1C gene cluster to bacterial cyanide assimilation as a nitrogen source
Linkage of the Nit1C gene cluster to bacterial cyanide assimilation as a nitrogen source
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DOI：
10.1099/mic.0.000668
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发表时间：
2018-07-01
期刊：
影响因子：
2.8
通讯作者：
Kunz, Daniel A.
中科院分区：
文献类型：
--
作者：
Jones, Lauren B.;Ghosh, Pallab;Kunz, Daniel A.
一个保守的基因簇（Nit1C）和细菌利用氰化物作为唯一的氮源的能力之间的遗传连锁被证明为9种不同的细菌。其中包括三种菌株，其氰化物营养能力以前已被记录（荧光假单胞菌Pf11764、恶臭假单胞菌BCN 3和肺炎克雷伯氏菌BCN 33），以及六种以前不知道具有这种能力的[伯克霍尔德氏菌（Paraburkholderia）xenovorans LB 400、Paraburkholderia phymatum STM 815、Paraburkholderia phytofirmans PsJN、贪铜菌（Ralstonia）eutropha H16、重氮营养葡糖酸醋杆菌PA15和扭脱甲基杆菌AM1]。对于所有的细菌，生长或暴露于氰化物导致的典型腈水解酶（NitC）的诱导连接到基因簇，特别是在Pf11764的情况下，转录水平的簇基因（nitBCDEFGH）的提高，和nitC敲除突变体未能生长。进一步的研究表明，高度保守的nitB基因产物也显着升高。总的来说，这些发现为Nit1C和氰化物上的细菌生长之间的遗传联系提供了强有力的证据，支持使用术语氰营养来描述可能代表微生物学中新的营养范式。在目前可用的基因组中对Nit1C基因进行更广泛的搜索，发现其存在于270种不同的细菌中，所有细菌都包含在细菌域中，包括革兰氏阳性厚壁菌门和放线菌门，以及革兰氏阴性变形菌门和蓝细菌门。Nit1C的出现可能与地球上第一次出现氰物种的时间一致，可以追溯到4亿至5亿年前。
A genetic linkage between a conserved gene cluster (Nit1C) and the ability of bacteria to utilize cyanide as the sole nitrogen source was demonstrated for nine different bacterial species. These included three strains whose cyanide nutritional ability has formerly been documented (Pseudomonas fluorescens Pf11764, Pseudomonas putida BCN3 and Klebsiella pneumoniae BCN33), and six not previously known to have this ability [Burkholderia (Paraburkholderia) xenovorans LB400, Paraburkholderia phymatum STM815, Paraburkholderia phytofirmans PsJN, Cupriavidus (Ralstonia) eutropha H16, Gluconoacetobacter diazotrophicus PA1 5 and Methylobacterium extorquens AM1]. For all bacteria, growth on or exposure to cyanide led to the induction of the canonical nitrilase (NitC) linked to the gene cluster, and in the case of Pf11764 in particular, transcript levels of cluster genes (nitBCDEFGH) were raised, and a nitC knock-out mutant failed to grow. Further studies demonstrated that the highly conserved nitB gene product was also significantly elevated. Collectively, these findings provide strong evidence for a genetic linkage between Nit1C and bacterial growth on cyanide, supporting use of the term cyanotrophy in describing what may represent a new nutritional paradigm in microbiology. A broader search of Nit1C genes in presently available genomes revealed its presence in 270 different bacteria, all contained within the domain Bacteria, including Gram-positive Firmicutes and Actinobacteria, and Gram-negative Proteobacteria and Cyanobacteria. Absence of the cluster in the Archaea is congruent with events that may have led to the inception of Nit1C occurring coincidentally with the first appearance of cyanogenic species on Earth, dating back 400-500 million years.