Key Laboratory of Marine Biogenetic Resources, The Third Institute of Oceanography, State of Oceanic Administration, Xiamen, China.
Environ Microbiol. 2010 May;12(5):1230-42. doi: 10.1111/j.1462-2920.2010.02165.x. Epub 2010 Feb 11.
Alkane hydroxylases, including the integral-membrane non-haem iron monooxygenase (AlkB) and cytochrome P450 CYP153 family, are key enzymes in bacterial alkane oxidation. Although both genes have been detected in a number of bacteria and environments, knowledge about the diversity of these genes in marine alkane-degrading bacteria is still limited, especially in pelagic areas. In this report, 177 bacterial isolates, comprising 43 genera, were obtained from 18 oil-degrading consortia enriched from surface seawater samples collected from the Atlantic Ocean. Many isolates were confirmed to be the first oil-degraders in their affiliated genera including Brachybacterium, Idiomarina, Leifsonia, Martelella, Kordiimonas, Parvibaculum and Tistrella. Using degenerate PCR primers, alkB and CYP153A P450 genes were surveyed in these bacteria. In total, 82 P450 and 52 alkB gene fragments were obtained from 80 of the isolates. These isolates mainly belonged to Alcanivorax, Bacillus, Erythrobacter, Martelella, Parvibaculum and Salinisphaera, some of which were reported, for the first time, to encode alkane hydroxylases. Phylogenetic analysis showed that both genes were quite diverse and formed several clusters, most of which were generated from various Alcanivorax bacteria. Noticeably, some sequences, such as those from the Salinisphaera genus, were grouped into a distantly related novel cluster. Inspection of the linkage between gene and host revealed that alkB and P450 tend to coexist in Alcanivorax and Salinisphaera, while in all isolates of Parvibaculum, only P450 genes were found, but of multiple homologues. Multiple homologues of alkB mostly cooccurred in Alcanivorax isolates. Conversely, distantly related isolates contained similar or even identical sequences. In summary, various oil-degrading bacteria, which harboured diverse P450 and alkB genes, were found in the surface water of Atlantic Ocean. Our results help to show the diversity of P450 and alkB genes in prokaryotes, and to portray the geographic distribution of oil-degrading bacteria in marine environments.
烷烃羟化酶包括整合膜非血红素铁单加氧酶（AlkB）和细胞色素 P450 CYP153 家族，是细菌烷烃氧化的关键酶。尽管这两种基因已在许多细菌和环境中被检测到，但关于海洋烷烃降解细菌中这些基因多样性的知识仍然有限，特别是在远洋地区。在本报告中，从大西洋采集的表层海水样本中富集的 18 个石油降解菌共获得了 177 株细菌分离株，包含 43 个属。许多分离株被证实是其所属属的第一批石油降解菌，包括短杆菌属、栖海菌属、利福索尼亚菌属、马泰利拉菌属、柯帝蒙氏菌属、副球菌属和蒂斯泰拉菌属。使用简并 PCR 引物，对这些细菌中的 alkB 和 CYP153A P450 基因进行了调查。从 80 株分离株中总共获得了 82 个 P450 和 52 个 alkB 基因片段。这些分离株主要属于Alcanivorax、芽孢杆菌属、Erythrobacter、马泰利拉菌属、副球菌属和 Salinisphaera，其中一些是首次报道编码烷烃羟化酶的。系统发育分析表明，这两个基因都非常多样化，并形成了几个聚类，其中大多数聚类是由各种Alcanivorax 细菌产生的。值得注意的是，一些序列，如来自 Salinisphaera 属的序列，被归入一个远缘的新聚类中。对基因与宿主之间的联系进行检查后发现，alkB 和 P450 往往在 Alcanivorax 和 Salinisphaera 中共存，而在副球菌属的所有分离株中，只发现了 P450 基因，但有多个同源物。alkB 的多个同源物主要在 Alcanivorax 分离株中共存。相反，远缘分离株含有相似甚至相同的序列。总之，在大西洋的表层海水中发现了各种含有不同 P450 和 alkB 基因的石油降解细菌。我们的研究结果有助于展示原核生物中 P450 和 alkB 基因的多样性，并描绘海洋环境中石油降解细菌的地理分布。
