Screening Of Active Myxobacteria And Product Isolation And Identification

Since the fifties of the20thcentury, many compounds with various antibioticactivities were found in myxobacterial, which attracted attentions on the screening ofbiologically active strains, especially on the isolation and identification of the secondarymetabolites with antibacterial, anti-tumor acitivities.In this study,16myxobacteria preserved in our laboratory were cultured in shakeflask, and we extracted the crude products, which were used to screen anti-fungal,anti-bacterial, anti-tumor activity strain.The strain of best anti-fungal activity was m03，which had a wide inhibitoryspectrum，and its bacteriostatic diameter of C. albicans、S. cerevisiae、A. fumigatus、Rhizopus、A. niger、P. expansum、Mucro are14.5mm、12.3mm、8.8mm、14.0mm、10.2mm、13.3mm、11.3mm，and the inhibition rate toward C. sasakiis and P. oryzaewere72.4%and69.3%。The strain of best anti-bacterial activity was m01，which couldinhibit the growth of B. enteritidis、E. coil、B. megaterium、S. aureus，and thebacteriostatic diameter were9.6mm、9.8mm、10.2mm、10.2mm、21.4mm，respectivelyStrain m01、m11and m16showed strong inhibitory activity on leukemia cancercells K562，and the IC50values were21μg/mL、11μg/mL and21μg/mL.Strain m03and m11were cultured in liquid culture morphological features ofshape、solid colony morphology、cell morphology and physiological and biochemicaltests, combined with16S rDNA molecular biology sequence alignmentfinalized fixedmyxobacteria strains m03was Myxococcus fulvus, and the strain m11was Myxococcusgenus.And we studied the growth characteristics of the two strains, including studying thegrowth curves of two strains, determine the two strains of C source corn starch, and thebest use of nitrogen source yeast extract, the best growth factorvitamin B12, the mostplus the inorganic salt magnesium sulfate, and the optimum pH8.0, the optimumtemperature30℃, when the rotation speed was140r/min, the inoculum size was10%,seed age was56h, the liquid volume was60mL, and the strains grow best, havemaximum biomass.Strain m03was made large-scale fermentation, and we extracted the crude productby a variety of separation, such as silica gel column, gel filtration, reverse phase column,the crude product was isolated and purified, and we gought5compounds finally, they were identificated by NMR and MS. Result showed that they were known compounds:M1, quinolin-4-ylmethanol; M2, myxothiazol; M3,4-quinolinecarboxaldehyde oxime;M4, N-(2-phenylethyl)acetamide; M5, N-acetyltyramine. Data showed that M2hadgood antifungal activity, and had the development value.