Phylogenetic analysis of bacterial diversity in Pacific Arctic sediments

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-,e-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 phylotypes in submarine plateau sediment P24 are α-,γ-,δ-Proteobacteria;While seventeen sequences from sediment S11 colleted from continental slop in the Chukchi Sea are grouped into α-,γ-,δ-,e-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 γ-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%).