Diversity Of Culturable Oligotrophic Bacteria In Water From The Arctic

The bacteria which survives in the Arctic attributes to extremophilic microrgani sms,extremophilic microrganisms are the oldest biological groups.Bacteria from the Arctic is adapt to the unique climate in the Arctic region,for example,strong a cid,dry, strong radiation, high salt, high pressure, cold, oligotrophic,and so on.The existence of the unique Arctic environment created the unique metabolism of ext remophilic microrganisms on the molecular level adaptation mechanism and the m etabolic level adaptation mechanism,these unique microrganisms play an indispens able role on biological cycles in the Arctic region. At the same time, they also b ears the origin of life, genetics, evolution and industrial values, and many other g reat mysteries.However, the vast majority is still unknown bacteria in such a huge library of extreme microbial resources.Study microbial diversity of the Arctic,will provide a theoretical basis for human explore species resources and microbial genetic resources in the Arctic.Isolation and identification of bacteria on the polar,will bring new strains of bioactive substances, the biologically active substances is likely to be source of new drugs and biological health care products, it has important industrial application.The contents of this thesis contains two parts:The diversity of culturable oligotrophic bacteria from the arctic and isolation,purification and primary identification of five microorganism strains from the arctic. This thesis is divided into the following three chapters:The first chapter:Literature review.A comprehensive overview of the status of the Arctic, describing characteristics of the arctic environment for the survival of bacteria;The status of people's development and utilization of marine microbial resources in the Arctic library;The methods of qualitatively and quantitatively researching microbial diversity; The methods of isolation and purification of oligotrophic bacteria;The status of researching microbial diversity and microbial purification and identification;The development prospects of the discovery, purification, identification, industrial use of Arctic microbial;The purpose of this study lies,research ideas and research significance of this thesis. The second chapter:Combining 16SrDNA library with PCR-DGGE method study the diversity of culturable oligotrophic bacteriain the Arctic marine.Seawater from the arctic ocean was broughten back by the arctic expedition team, oligotrophic bacteria was cultivated in dialysis room continuously.Then, cultivated the bacteria again on oligotrophic medium for obtaining oligotrophic bacteria which is difficult to be cultivated.In order to analyze the bacterial population diversity in arctic seawater of N83 station and C19 station, we combined 16SrDNA library with PCR-DGGE method studing the diversity of culturable oligotrophic bacteriain the Arctic marine,The results indicated that the bacterial community was high diversity. The cultivated oligotrophic bacteria of N83 station could be divided into three groups:the donminant group was Alphaproteobacteria,accounting for 90.01% of the total sequences;followed by Gammaproteobacteria and Sphingobacteria, accounting for 5.00% of the total sequences.And the cultivated oligotrophic bacteria of C19 station could be divided into four groups:Alphaproteobacteria and Actinobacteria were the donminant groups,respectively, accounting for 67.87% and 28.57% of the total sequences;followed by Gammaproteobacteria and Glaciecola, accounting for 1.79% of the total sequences.The phylogenetic tree indicated that most sequences of the 16SrDNA gene clone library were far from the sequences known in the GeneBank,this indicated that there must be unknown bacteria to be separated.The third chapter:The purification and preliminary identification of five strains oligotrophic bacteria from Arctic seawater.The five strains oligotrophic bacteria were separated by being cultivated continuously,we identified by their 16SrRNA gene identification and preliminary morphological analysis separately.The phylogenetic trees were constructed on basis homology characteristic of 16SrDNA, and carrying out the homology analysis. The results indicated that five oligotrophic bacteria strains belong to:Halomonas, Roseobacter, Glaciecola, Rhodococcus, Brevundimonas. By observing the formation of these strains'colonies reveals:Rhodococcus colonies showes yellow, the others were white.And did the Gram stain test at last.