The Identification And Activities Screening Of Three Actinomycete Strains Isolated From Special Habitats

Objectives According to the results of antibacterial activity screening and morphological characteristics,some strains were selected from the rhizosphere actinomycetes collection and endophytic actinomycetes resource separated from Acanthopanax senticosus.Firstly,the inhibitory spectrum and the secondary metabolite biosynthesis genes were screened,then the strains were identified.The modern systematic theory and method can be used to excavate the actinomycetes with important biological activity.The special morphological strains were placed on the appropriate taxonomic boundary to enrich actinomycete classification system,which establishes a good basis for further find new compounds with new biologically active and new structures.Methods Paper disc diffusion method was used to test the antimicrobial activity and the stability of strains,the biosynthesis genes(PKS I,PKS II,NRPS,Halo,and CYP)were obtained by PCR,and then sequences were cloned and analyzed.The strains were identified by characteristics of phenotypic,physiochemist and 16S r RNA sequences.Based on the colony observation and 16S r RNA sequence of strains,A special actinomycete strain was selected from the strain library,and the new genus was identified by polyphasic taxonomy identification.Results We obtained the endophytic actinomycetes 13-12 and 13-85,separated from Acanthopanax senticosus,with good antibacterial activity.Fermentation broth of strain 13-12 showed antimicrobial activity against the test strains Staphylococcus aureus,Bacillus subtilis,Mycobacterium phei and MRSA.It had stable activity at 4-20°C and p H 6.0-8.0.Besides,the strain contained NRPS and Halo genes.Strain 13-12 has the potential for synthesizingβ-lactam antibiotics,macrolide antibiotics,or similar products.The strain was preliminarily identified as one strain of Planomonospora sphaerica,a valid species of the genus Planomonospora.The fermentation broth of the strain 13-85 showed broad-spectrum,had different inhibitory effects on 10 kinds of testorganism,and it was stable under natural light conditions.When separating the effective antimicrobial active substance,the temperature should be controlled at about 20°C and the p H is controlled at 4-8.The strain 13-85 contains PKS II and NRPS genes,and it has great potential for synthesizing neomycin,streptolydigin,oligomycin or similar products.The strain 13-85 was identified as one strain of Streptomyces amritsarensis,a valid species of the genus Streptomyces.Through polyphasic taxonomy identification of rhizosphere actinomycetes strain 11-183represents a novel species of the genus Actinophytocola,for which the name Actinophytocola xanthii 11-183~T(=MCCC 1K02062~T=KCTC 39690~T)(The article has been indexed by International Journal of Systematic and Evolutionary Microbiology.).The strain 11-183 was preserved in Marine Culture Collection of China(MCCC)and the Korean Collection for Type Cultures(KCTC).Conclusions The strain 13-85 was identified as one strain of Streptomyces amritsarensis;the strain 13-12 was preliminarily identified as one strain of Planomonospora sphaerica.11-183 represents a new species of the genus Actinophytocola,named Actinophytocola xanthii.Which further enriched the genus taxon of genus Actinophytocola.The strain 13-12 and 13-85,endophytic actinomycetes from Acanthopanax senticosus,have good antibacterial activity and the potential for the synthesis of secondary metabolites,which can be used as a high quality actinomycetes source for screening new antibiotics.The antibacterial stability of the fermentation broth and the exploration of the functional gene of strains lay a solid foundation for the separation and purification of the antibacterial active substances.This is of great significance to the development of new microbial drug resources.Figure 22;Table 18;Reference 147...