Myxobacteria As A Resource For New Chemical Discoveries

Myxobacteria are Gram-negative unicellular bacteria that can produce biologically active secondary metabolites. The Crews Laboratory has been engaged in research to isolate marine myxobacteria with the aim of discovering novel secondary metabolites of biomedical importance.  To accomplish this we takes expeditions to locations across the Indo Pacific to collect marine sediment and sponges for testing.  The marine derived samples are streaked using nutrient deficient agar plates baited with E. coli then transferred to nutrient rich agar media and a period of myxobaterial growth (8-14 days).

To be discussed in this poster as a proof-of-concept project is our work on the strain 108A05C; obtained from a marine sediment sample isolated from American Samoa Islands. The extract of the culture broth tested positive at the UCSC Chemical Screening Center for HeLa cytotoxicity. The myxobacterial strain was brought up from the nutrient rich agar media in a liquid preculture of 1L (MD1-Y) and then inoculated into 20 liters MD1-Y liquid media with XAD-16 resin tea bags to sequester the secondary metabolites for testing. Purification continues with the Kuphchan extraction method to partition metabolites into fractions of different polarities. With the use of a peak library of the strain 108A05A into a 96 well plate, collaboration with UCSC Chemical Screening Center and the use of spectrometric methods such as HPLC, DART MS, and NMR allow us to discover compound(s) of interest. Further investigation of these types of compounds, by this method, will yield insight to novel leads and potential candidates for future disease therapeutics.