| Myxobacteria have proven over the years that they are a significant source of novel secondary metabolites. One member of this group, Sorangium cellulosum, is an especially prolific producer of secondary metabolites with novel bioactivities. This organism is unique among the myxobacteria in that it is the only member that can degrade cellulose. It is estimated that nearly 100% of all Sorangium produce a bioactive compound. Of all the compounds described for this organism, arguably the most significant are the epothilones. Epothilones stabilize microtubules via a mechanism identical to that of Taxol. However, very few S. cellulosum strains produce epothilones. In a search for additional S. cellulosum strains with anticancer activity distinct from epothilones, a panel of yeast strains obtained from the National Cancer Institute with altered DNA damage repair mechanisms or cell cycle control was screened for inhibition using a cell proliferation assay based on the substrate MTS and a paper disk diffusion assay. The melanoma cell line WM1552C was also utilized to investigate anticancer activity of the extracts. In this study, we also investigated the anti-microbial activities of S. cellulosum secondary metabolites. These studies are particularly relevant since organisms such as Staphylococcus aureus are a major cause of community- and hospital- acquired infections. Indeed, an extract prepared from S. cellulosum strain SMP 313-1 significantly inhibited methicillin resistant S. aureus in a paper disk diffusion assay. Subsequently, a pure bioactive molecule with a molecular weight of 758 Daltons and an absorbance maximum of 300 nm was obtained from SMP 313-1 extracts. |
