红灯食烷菌（Alcanivorax hongdengensis）黄素结合单加氧酶（AlmA）的基因克隆及其烷烃诱导表达

Identification of AlmA genes involved in long-chain alkane degradation by Alcanivorax hongdengensis A-11-3

摘要:

摘要：【目的】研究海洋烷烃降解菌新种模式菌株Alcanivorax hongdengensis A-11-3降解长链烷烃的分子机制。【方法】PCR克隆编码黄素结合单加氧酶的基因序列，利用生物信息学软件对序列进行分析，运用RT-PCR和实时荧光定量PCR技术分析基因在不同烷烃诱导下的表达水平。【结果】从菌株A-11-3中克隆获得了两个黄素结合单加氧酶基因片段（almA1 和almA2）。它们编码的氨基酸序列与菌株Acinetobacter sp. DSM 17874的AlmA同源性分别为58.6% 和53.2%。实时荧光定量PCR分析表明，almA1基因只在长链烷烃（C28－C32）的诱导下上调表达，而almA2基因中能在更宽范围的长链烷烃（C24－C34）和支链烷烃诱导下上调表达。两者均在C9－C22的烷烃诱导下没有上调表达。【结论】黄素结合单加氧酶可能是A-11-3降解长链烷烃和支链烷烃的关键酶。

Abstract:

Abstract: [Objective] The aim of this study is to identify of genes involved in long-chain (LC) alkane degradation in Alcanivorax hongdengensis A-11-3. [Methods] PCR was applied to obtain Flavin-binding monooxygenase genes, then quantitative real-time polymerase chain reaction (Q-RT-PCR) and RT-PCR were applied to analyze gene expression in response to different LC-alkanes and pristane. [Results] Two homologues, almA1and almA2, were obtained. They showed 58.6% and 53.2% similarities with almA of Acinetobacter sp. Strain DSM 17874, respectively, at amino acid level. Enhanced expression of almA1 genes was observed when strain A-11-3 grew with long chain alkanes (C28 to C 32), in sodium acetate medium. However, the induction expression was not observed in the case of C9-C22 alkanes. Similarly, almA2 was induced by long chain alkanes (C24 to C 34). In addition, it was also induced by the branched alkane pristane. [Conclusion] AlmA genes were mostly responsible for the degradation of long-chain alkanes and pristane in strain A-11-3.