北极太平洋扇区海洋沉积物细菌多样性的系统发育分析

Phylogenetic analysis of bacterial diversity in Pacific Arctic sediments

对北极太平洋扇区3个不同深度的海洋沉积物样品，采用PCR结合变性梯度凝胶电泳（DGGE）技术进行细菌16SrRNA基因V3区序列的系统发育分析。结果表明，同一个沉积物样品不同层次的DGGE电泳图谱不完全相同。从3个沉积物样品中共获得50条序列。大部分序列与从海洋环境尤其海洋沉积物获得的细菌16SrDNA序列相似性较高（88％-100％），归属于变形细菌（Proteobacteria）的gamma亚群、alpha亚群、beta亚群、epsilon亚群、delta亚群，Cytophaga-Flavobacterium-Bacteroides（CFB）群细菌和高G＋C含量的革兰氏阳性细菌等系统分类群，其中变形细菌（Pmteobacteria）的gamma亚群为沉积物中的优势细菌类群。

Using PCR-DGGE （denaturing gradient gel electrophoresis） methods, bacterial phylogenetic diversity in three Pacific Arctic sediment samples were investigated, taken from different depths in the range of 47 m to 3850 m. DGGE profiles of different layers in the same sediment sample are not completely same. 16S rDNA sequences corresponding to 50 excised bands from three sediment samples were analyzed and fell into seven lineages of the domain Bacteria. α-, β-, γ-, δ-, ε- Proteobacteria, the Cytophaga- Flavobacterium-Bacteroides （CFB） group and Actinobacteria. However, the composition of bacterial phylotypes in three sediments is different. Fourteen sequences obtained from sediment B78 collected from the Canadian Basin belong to β-, γ- Proteobacteria, Comamonadaceae and Acidobacteria. Bacterial phytotypes in submarine plateau sediment P24 are α-, γ-, δ-oProteobacteria; While seventeen sequences from sediment Sll colleted from continental stop in the Chukchi Sea are grouped into α-, γ-, δ-, ε- Proteobacteria, the Cytophaga-Flavobacterium-Bacteroides （CFB） group and Actinobacteria. It is suggested the different characteristics of three sediments may cause the difference in the composition of bacterial phylotypes. 16S rDNA sequences from members of 7-Proteobacteria dominated three sediments samples. The majority of the sequences were most closely related to uncultured marine environmental sequences, especially marine sediment environmental sequences （88% - 100% ）.