Study On The Bioactive Metabolites And Antagonism Mechanism Against Pathogens Of Two Streptomyces Diastaticus

Actinomycetes are important flora in microorganisms,their secondary metabolites are rich in structures and diverse in biological activities,such as anti-bacterial,anti-fungal,anti-tumor,immunosuppressive agent,they are important sources of microbial drugs.In this thesis,two actinomycetes strains YIM PH20095 and YIM PH20246 with better antibactiral activities and rich component in secondary metabolites were selected from 17 actinomycete strains for their secondary metabolites and antifungal activities mechanisms research.They were identified as Streptomyces diastalicus subsp.ardesiacus by 16S rRNA gene sequence analysis.By means of chromatographic separation technologies,12 compounds were obtained from the fermentation broth of strain YIM PH20095,the mass spectrometry and NMR data were used to determine their structures.They are 8-hydroxyphenazine-l-carboxylic acid,2,5-piperazinedione,6-[(4-hydroxyphenyl)methylene]-1-methyl-3-phenylmethylene,newphenazine A,newphenazine B,9-methoxyphenazine-1-carboxylic acid,methyl benzoate,newphenazine C,1-methoxyphenazine,1,6-phenazinedicarboxylic acid,newphenazine D,newphenazine E,newphenazine F.Among them,compounds newphenazine A-F are new compounds that have never been reported in literature.7 compounds were obtained from the fermentation broth of strain YIM PH20246,they are 1-hydroxyphenazine,newphenazine G,6-carbamoylphenazine-1-carboxylic acid,newphenazine H,7-hydroxy-6(methoxycarbonyl)phenazine-1-carboxylic acid,phenazine-1-carboxamide,6-hydroxyphenazine-l-carboxylic acid.Among them,compounds newphenazine G-H are new compounds that have never been reported in literature.Four fungi that caused root rot diseases of notoginseng and five common pathogenic bacteria were selected as indicator strains.19 compounds have different degrees antimicrobial activities against the tested pathogens with MIC values from 8 to 512?g/mL.In addition,the antagonism mechanism against P.cucumerina of strain YIM PH20095 was studied by growth rate and spore germination methods.