中文摘要：

【目的】从广东省土样中分离并鉴定获得粘细菌，以丰富资源微生物库，并对其进行抗肿瘤活性的初步研究，为寻找新的抗肿瘤药物及其开发应用奠定基础。【方法】用灭活大肠杆菌诱导法，从广东土样中分离得到粘细菌，通过菌落形态观察、扫描电镜、生理生化特征、以及16srRNA基因序列同源性分析，鉴定并归类细菌。测定不同生长时期代谢产物的抗肿瘤活性，分离纯化次级代谢产物得到抗肿瘤活性组分，测定抗肿瘤活性组分抗肿瘤谱及其对应的半致死浓度。利用激光共聚焦显微镜观察抗肿瘤活性组分作用B16后的亚细胞结构变化。【结果】分离并鉴定了粘细菌STXZ54新菌株，命名为Myxococcus macrosporus STXZ54，该粘细菌产生的抗肿瘤活性代谢产物能够较好地抑制B16、Hela、HCT-116、4T1、Hep-3B等多种肿瘤细胞，初步分离其代谢产物得到活性组分SGF5。经MTT实验算出SGF5对B16、Hela、Hep-3B、4T1细胞的IC50均在10ug／mL左右，对HCT-116细胞的Ic如是70．ug／mL。利用激光共聚焦显微镜观察到活性组分SGF5作用B16后亚细胞结构出现了明显的变化，结合细胞坏死与凋亡的检测初步判断SGF5能引起B16细胞的凋亡。【结论】从土样中分离得到粘细菌STXZ54，对分离到的活性组分进行了细胞毒性试验，证实其具有较好的抗肿瘤活性，有开发成抗肿瘤药物的潜在价值。

英文摘要：

[ Objective] We isolated Myxobacteria strains from soil samples collected from Guangzhou, identified the strain and studied the antitumor activity. [ Methods ] 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. [ Results ] 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 ICsovalues of 10 ug/mL, and HCT-116 cell with IC50 values of 70ug/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. [ Conclusion] 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.