[Isolation and identification of Myxobacteria strain STXZ54 with antitumor activities].

We isolated Myxobacteria strains from soil samples collected from Guangzhou, identified the strain and studied the antitumor activity.We isolated Myxobacteria strains from soil samples through inactivated E. coli inducing method, identified the strain according to morphological observation, physiological and biochemical characteristics, and the homologous analysis of 16S rRNA sequences of nucleotides. The antitumor spectrum and the corresponding IC50 of the active component separated from the culture was analyzed. Confocal laser scanning microscope was used to examine the growth inhibitory effect of the active component on B16 cells.We isolated a Myxobacteria strain and identified as Myxococcus macrosporus STXZ54. The active component termed SGF5 showed cytostatic activity against B16, Hela, 4T1, Hep-3B with IC50 values of 10 microg/mL, and HCT-116 cell with IC50 values of 70 microg/mL. Subcellular structure of B16 cells were abnormal observed by confocal laser scanning microscope. Combining the apoptosis and necrosis assay result it is likely that SGF5 can induce apoptosis of B16 cells.The active component separated from the culture of Myxococcus macrosporus STXZ54 has a significant antitumor activity tested by cytotoxicity assay, which was worth exploiting as potential antitumor drugs.