Studies On Diversity Of Actinomycetes In The North Pole Marine Sediments

Actinobacterial diversity in the North Pole sediments was investigated by selectiveisolation method and culture-independent method. All isolates had been carried out, aswell as enzyme production analysis, PKS/NRPS gene amplification and antibacterialactivity screening.81strains of actinomycetes were isolated from35sediment samples. They wereclassified to the class actinomycetes include10genuses: Pseudonocardiace,Mycobacteriu, Micrococcaceae, Microbacteriaceae, Dermabacteraceae andBrevibacteriaceae of7Families: Pseudonocardia, Mycobacterium, Kocuria,Microbacterium, Micrococcus, Brachybacterium, Brevibacterium, Actinotalea,Kytococcus and Arthrobacter, and the advantage bacterium was Pseudonocardia.Comparative analysis of16S rDNA sequence showed that the novel strain was mostclosely related to genera within the family Actinotalea, but formed a separate lineage.The strain1112D-41had only96.957%similarity to the standard strains with the closestrelationship respectively.8strains and15protease-producing strains were screened from81actinomycetesaccording the size of transparent circle. Ones of lipase-producing, cellulose-producingand chitinase-producing were not isolated.8amylase-producing strains were shown torepresent strains from3genera: Micrococcus, Brachybacterium and Brevibacterium.The strain1131S-22was the best amylase-producing one.15protease-producing strainswere shown to represent strains from6genera: Kocuria, Microbacterium, Micrococcus,Brachybacterium, Brevibacterium and Actinotalea. The biggest size of the transparentcircle Kocuria、Microbacterium and Micrococcus.The antimicrobial activities of fermentation supernatant and fermentation liquidliquid extraction in AM3medium and N4medium were tested with4indicator microbes:E. coli、S. aureus、B. subtilis and C.albicans. The antimicrobial activity of fermentationsupernatant from only one Pseudonocardia was weakly, and that of fermentation liquidliquid extraction was outstanding from16%of isolates. Molecular screening was doneto detect the existence of PKS and NRPS genes of the isolates using primers designed toamplify their conserved region.37.03%of the isolates had type PKS I gene while11.11%had type PKS II gene and29.63%had type NRPS gene.1110D-64(1)、1110D-63and1110D-64(2) from Mycobacterium had type PKS I, PKS II and NRPS genes.We researched the diversity of the uncultured actinomycetes in4different depthssamples of the Arctic marine sediment using the16S rDNA library construction method.Though16SrDNA PCR, we found14of them belong to actinomycetes including11uncultured actinomycetes and3cultured actinomycetes. The3cultured ones belong toPseudonocardia, Mycobacterium and Kocuria respectively.The analysis results of two mehods selective isolation and culture independentshow that the actinomycetes in Arctic marine sediment samples have diversitys.Thisresults provide a theoretical basis of developing new type actinomycetes. Though this,the two results have significant differences: the independent culture got less informationof cultured actinomycetes that maybe the cloing was not enough to get a well result; butmore information of uncultured actinomycetes, that because the most actinomycetescouldn’t get using above method and the actinomycetes diversity in Arctic marinesediment still need further research.