| Myxobacteria widely exist in all kinds of soil,there are about 103 ~106 bacteria fruit bodies in per gram of soil,their process of growth is extremely complicated cellulous behavior,they can send signals、induct synergistic feeding between cells while growing up,at the same time,myxobacteria have the ability of movements and development into fruit bodies. Therefore, myxobacteria have very obvious feature of sociology. Considering many differences of myxobacteria from general microbe, the novel character make themselves substantial in the field of microbiology.With more and more secondary metabolites of myxobacteria having pharmacological and biological activity have been found, myxobacteria in pharmaceutical bacteria have got more attention of scientists expectably, and rise to the third place instead of pseudomonas rapidly. The reported active metabolites of metabolites have more than ten kinds, including aromatic heterocycles、quinones、macrocycles、polyene、polyether and peptide compounds, more than seventy basic separation structures of secondary metabolites have been found comparing to only three ones in other microbes had been reported. In the second place, another character is that myxobacteria can produce a lot of analogues on account of one basic structure; this provides dependable resources for efficient screening and harmless pro-drugs and compounds. As is well known that Myxobacteria have specificity in strains rather than in species or genus, hundreds of different types of compounds can be produced by one stain at the same time, almost all can stop the growth of eukaryotic cells to a certain degree as potential pharmaceutical compounds or lead compounds, among them there are some compounds could stop the growth of cancer and fungi, their inhibitory activity are much higher than other microbes. Otherwise, there are superb applicated values in extracellular phlegm and polysaccharide of myxobacteria in the progress of human health care.In this extracorporeal cytotoxicity screening experiment, two kind of myxobacteria metabolites NX52 and NX83 were used, which provided by large-scale Qin-ba mountains myxobacteria and metabolites collection built by Institute of Microbiology of Shaanxi Province. Colorectal cancer cells SW480 and SW1463 were treated with diffenent concentrations of metabolites 0.1mg/ml、1mg/ml and 10mg/ml after a certain hours, the cytotoxicity of NX52 and NX83 was tested in order to lay a available foundation of overall screening in myxobacteria and metabolites collection in the future. Later,further analyzing the chemical of these crude extracting, exploiting and studying the activity of anti-cancer and anti-fungus in the separation and purification,that would be helpful to development and utilization of the biological resources of myxobacteria.The experiment revealed that through methyl thiazolyl tetrazolium(MTT) colorimetric method, different concentration of crude extracting NX52 and NX83 has inhibitory effect in proliferation of human colorectal cancer cells SW480 and SW1463 after a certain hours(24h、48h and 72h), with the metabolites duration extension and concentration enrichment, the proliferation inhibitory effect on colorectal cancer cells SW480 and SW1463 is growing much stronger, the two metabolites have time-dependent and dose-dependent in the proliferation inhibitory effect on the colorectal cancer cells. Because of the much more outstanding inhibitory effect on the colorectal cancer cells, the metabolite NX83 was chosen to be a potential of anti-tumor drugs in the next further cytotoxicity experiment.After 48 hours, the apoptosis rates of concentration 0.1mg/ml and concentration 1.0mg/ml of crude fermentation extracting NX83 are higher than the control group. With the crude fermentation extracting concentration enrichment, more and more early apoptosis and late apoptosis/ necrocytosis cells are coming up. This proves that, to some degree, myxobacteria metabolites NX83 could kill cancer in vitro, which is possibly by inducing the apoptosis of tumor cells. |
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