Isolation And Identification Of Myxobacteria And Study On Its Antibiotic Activity

Myxobacteria are a class of Gram-negative bacteria with complex multicellular behavior,They are unicellular bacteria and can gliding motion.Majority of Myxobacteria will form multicellular fruting body and myxospore, and myxospore have strong stress resistance.They have great research value in screening natural drugs, because their metabolites have rich, diverse and novel biological activities.In this study,we isolated myxobacteria by rabbit dung pellets and filter paper methods, the soil samples were from some areas of Inner Mongolia.We identified the strains by fruting body and colony morphology,their physiological and biochemical characteristic,16S rDNA molecular methods. In order to elucidate the myxobacteria interspecies relationship, analyzed sequence and constructed phylogenetic tree.Analysis the strains of isolated myxobacteria antibacterial and antifungal activity.In this study,67strains of bacteria were isolated,and66of them with the morphological features of Myxobacteria,they have Fruiting bodies with bright colors and different colony morphology, obtained35strains of pure strain by direct transfer and antibiotic treatment.The classification and identification display:these strains belong to6genera in myxobacteria:Myxococcus(16strains); Corallococcus(10strains); Archangium(3strains); Cystobacter(2strains); Sorangium cellulosum(2strains); Angiococcus(2strains).16S rDNA sequence analysis revealed the highest seguence homology of all the isolated myxobacteria strains displayed more than98%with known strains. In addition, obtained a strain named wt-4,its colony morphology is differ from Myxobacteria,16S rDNA sequence analysis revealed the type stain Sphingomonadaceae bacterium. as its closest homolog,display94%sequence similarity.It may be a new genus,that need for further research and identification.Futher,these strains were analyzed for their antibiotic activity,the results indicated that all the isolated Myxobacteria are exhibited to inhibit one or more antibacterial activity,23strains of them can inhibit the growth of E. coli,17strains could inhibit the growth of Bacillus subtilis,18strains can inhibit the growth of Staphylococcus aureus,18strains can inhibit the growth of Saccharomyces cerevisiae,31strains can inhibit the growth of potato late blight pathogen, but had no strains resistance to Sclerotinia sclerotiorum and potato black scurf disease pathogen. This work will lay a foundation for the further research on myxobacteria and new drug discovery and development in Inner Mongolia.