| 趋磁细菌的地域分布特征 |
| 摘要点击 5245 全文点击 3800 投稿时间：2009-04-03 修订日期：2009-05-27 |
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| 中文关键词 趋磁细菌 16S rDNA序列分析 系统发育 地域分布 |
| 英文关键词 magnetotactic bacteria (MTB) 16S rDNA sequence analysis phylogeny analysis geographical distribution |
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| 中文摘要 |
| 通过对来自目前GenBank中趋磁细菌的16S rDNA序列分析，并进行系统进化树的构建，比较不同区域趋磁细菌的差异．目前，GenBank中共有239条趋磁细菌16S rDNA序列，相似性分析后有137条不同的序列（海洋55条，淡水82条），分属于变形菌门和硝化螺菌门．全长序列的系统进化分析显示，全球趋磁细菌的分布具有一定的区域性，海洋与淡水趋磁细菌区分明显．不同地域的趋磁细菌的系统进化分析显示，近海与大洋的趋磁细菌有明显的差别；而同为海洋或淡水的环境中，如巴西和美国近海、德国和中国的淡水湖泊，趋磁细菌相 |
| 英文摘要 |
| Magnetotactic bacteria (MTB) are widely distributed in aquatic environments. To assess the correlation between their evolutionary relatedness and geographic distribution,we analyzed 239 16S rDNA sequences available in the Genbank,and constructed phylogenetic trees based on the sequences. After elimination of redundant sequences by grouping those with identity >97% into a single one,we analyzed in detail total 139 16S rDNA sequences,including 55 from marine MTB and 82 from freshwater sequences,and belonging to Proteobacteria and Nitrospirae. Phylogeny analysis based on those sequences suggests that the geographical distribution of MTB has certain regional distribution character: marine MTB is distinct from freshwater MTB,and off coast MTB are remotely related with ocean MTB. In contrast,the MTB from similar habitats,such as offshore in Brazil and the United States or freshwater lakes in Germany and China,are closely related. It is found that similar species have a large geographic distribution and tend to adopt the similar habitats,morphotypes of MTB and their living environment conditions have a significant relevance. This observation suggests that MTB may have multiple evolutionary origins. And also,it suggests the environmental conditions,as an important evolutionary pressure,play an important role in the long-term evolution of MTB. |
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