Classification And Identification Of The Actinomycetes From Anti-infect Soil

Because of the superiority producing antimicrobial biological activity substances,actinomyces,especially streptomyces,is continously the focus on the discovery of new antibiotics.At the same time,along with successive researches on a variety of actinomycetes and discoveries of new antibiotics,the discovering probability of new actinomycetes strains isolated from ordinary habitats and new antibiotics is getting less.Based on the inference that new antibiotics would be discovered in new habitat or special habitat,many scholars expect to constantly discovering new antibiotics and other bioactive substances produced by new actinomycetes strains isolated from special habitat.Sixty-one actinomycetes strains have been isolated from an anti-infection soil samples which is used to prevent the wound infection after dog's bite by Chinese people in our previous research.The anti-MRSA activities of their broth were evaluated,and the result showed that the broth of six strains among them indicated remarkable anti MRSA activities.So,classification and identification of this six strains were achieved with multiple classification method,and a important foundation for the further researches of anti MRSA active metabolites and the discovery of new antibiotics will be established through this research.Moreover,the genetic relationship of microbial communities in the anti-infection soil can be preliminarily developed,which will be helpful to further research on the anti-infection soil.Multiple classification as the morphological characteristics,culture characteristics,physiological and biochemical characteristics,chemical analysis of cell wall and cell membrane,16 S rRNA sequence analysis of this six strains will be used in this research,which include:(1)The physiological and biochemical characteristics research shows that: the most optimum temperature of the 6 strains Y1?Y2?Y7-Y10 is 30-35?;the most optimum pH of strains Y1?Y2?Y7?Y8 is in the range of pH 6-8,the most optimum pH of strains Y9?Y10 is in the range of pH 4-6.5;salinity has a great effect on growth of the 6 strains,they can grow well if the salinity lower than 1%,they began to appear when the salinity more than 5%;the fermentation extracts of the 6 strains showed antibacterial activity in different levels to indicator bacteria,especially have significant antagonistic activity to multiple drug fast bacteria MRSA.In addition,strain Y1 ? Y9 ? Y10 also have the antibacterial activity to Candida albicns,Y2 has the antibacterial activity to Escherichia coli.(2)Chemical analysis of cell wall and cell membrane shows that: there are LL-DAP and Gly in the amino acids of cell wall,Xyl in the cell wall polysaccharides,the cellmembrane lipid phosphate containing only PE which is phosphor lipid of type ?.(3)16S rRNA sequence analysis shows that: through the 16 S rRNA sequence analysis of the 6 strains and construct the phylogenetic tree,we finally identify them as Streptomyces.The result is as same as the result of morphological characteristics and chemical analysis.Also,Through the phylogenetic tree analysis,we know that strains Y1?Y2?Y8 and Streptomyces eurocidicus?Streptomyces stramineus?Streptomyces netropsis gathered together with close genetic relationship;strains Y7 and Streptomyces cinnamonensis?Streptomyces cinnamonensis ?Streptomyces virginiae?Streptomyces manipurensis gathered together with close genetic relationship;strains Y9 ? Y10 and Streptomyces cinnamonensis?Streptomyces cinnamonensis?Streptomyces virginiae?Streptomyces manipurensis gathered together with close genetic relationship.According to the result of multiphase classification and identification,all of 6strains isolated from the same habitat are classified as Strepatomyces sp..Furthermore,a close genetic relationship between them was found,and meanwhile,the result of physiological and biochemical characteristics analysis showed that all of the 6 strains have significant ant--MRSA activity.