中文摘要：

【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.DSM17874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。

英文摘要：

[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-113.