Diversity Of Cultivable Actinobacteria In The Intestines And Stomach Of A Mesoplodon Densirostris And Polyphasic Taxonomy Of Three Marine Actinobacteria

Actinomycete has complex morphological differentiation process and the ability to produce variety of metabolite,they are a kind of important industrial microorganisms.The past screening of antibiotics and the recent research results of microbial genomics,show that actinomycete play an extremely important role in the production and selection of natural products.In recent years,the increasing of drug resistance,stubborn disease,and new diseases,indicate the strongly need of effective new drugs,so that scientists turn their eyes on some new resource of actinomycete.The gut of animal is a typical and unique environment,and in the past the resources research of cultivate actinomycete in the gut was few.According to the query,scientists in domestic and foreign mainly focus the study of gut microorganism on human,livestock and poultry animals,but less on marine mammals,especially the diversity research of cultivate actinomycetes in their gut is least.In this article,using method of culturable analysis,we isolated 143 strains from 11 samples of intestines and stomach of a Mesoplodon densirostris,the strains belong to actinobacteria,including three orders,ten families,thirteen genus,in which the Brevibacterium(40.56 %)and Kocuria(37.06 %)are the dominant genera.There were significant differences in the number of cultivable strains and genus using different medium.Using 2216 E medium isolated 72 strains of actinomycete,that occupy half of total strains;and using glycerin-asparagine medium isolated 24 strains belonging to eight genera.Using mothur software divided the strains that more than 97 % homology into 20 OTUs,then in every OTU choose one representative bacterial strains for screening genes encoding type I,type II polyketide synthases,nonribosomal peptide synthases by polymerase chain reaction and antimicrobial assay.The results show that the coverage of PKS I,PKS II and NRPS was 25 % respectively.The inhibition ratio to Bacillus thuringiensis,Bacillus subtilis,Sptaphylococcus aureus and Escherichia was 100 %,55 %,10 % and 5 % respectively.None of 20 representative actinobacteria showed any inhibitory action to Fusarium oxysporum,Colletotrichum gloeosporioides,Rhizoctonia solani and Sclerotinia sclerotiorum.In addition,using the Polyphasia taxonomy method,we studied the taxonomic charateristics of three marine actinobacteria GY0594~T,GY0556~T,WP1~T,isolated from deep-sea water of Western Pacific,sediment of Western Pacific,and sediment of Southwest Indian respectively.It showed that strain GY0594~T represent a new novel species of the genus Nocardioides,which name was Nocardioides rotundus,the type strain GY0594~T(= MCCC 1A10561~T = KCTC 39638~T);strain GY0556~T represent a new novel species of the genus Pseudonocardia,which name was Pseudonocardia citri,the type strain GY0594~T(=MCCC 1A10574~T = KCTC 39641~T);strain WP1~T represent a new novel species of the genus Amycolatopsis,which name was Amycolatopsis albosporeus,the type strain WP1~T(=MCCC 1A10745~T = KCTC 39642~T).