Anti-infective and cytotoxic secondary metabolites in Fungi and yeasts from Hawaiian marine environments

Hawaii's marine mycoflora is phylogenetically diverse and in some cases unique to the Hawaiian archipelago (Donachie et al., 2004). Since much of this flora is unlikely to have had little if any contact with clinically important bacterial or fungal pathogens, we predict that secondary metabolites expressed by Hawaii's marine mycoflora may be effective against emerging microbial threats, and any or all of a range of human cancer cells. Just a handful of terrestrial microorganisms provide most currently used antibiotics. Using only a narrow range of antibiotics, however, risks the development of resistance developing and spreading among pathogens. For example, vancomycin is widely considered a 'last resort' treatment when other drugs have proven ineffective, but resistance to this potent antibiotic among enterococci is a growing threat. The threat is enhanced when one considers the likelihood of transfer of resistance from vancomycin resistant enterococci to other bacteria.

To counter the growing threat posed by antibiotic-resistant bacteria, Fungi and yeasts, we must expand the diversity of antimicrobial agents available to medical professionals. Material from under-represented taxa and unexplored sites or niches is ideal starting material (Colwell, 1997, 2000). In this respect, the collection of marine-derived Fungi and yeasts we have established is a valuable resource. Discovery work in the field of bio-active secondary metabolites has tended to focus on non-microbial sources, such as marine invertebrates, but because the target molecule is usually present in extremely low concentrations these sources rarely meet the demand for raw material (Jensen & Fenical, 2000, 2002). Marine microorganisms can meet the material demand because large quantities are generally easy to produce. In this project we are isolating Fungi and yeasts from diverse marine habitats around Hawai'i, and screening cultivated strains for antibiotic and cytotoxic activities. As of October 2006, a total of 689 isolates have been cultivated, ~90% of which have been sequenced and submitted to Genbank with accession numbers EF060395-EF060975 (http://www.ncbi.nlm.nih.gov/).

Collaborators

Prof. Thomas K. Hemscheidt, Department of Chemistry, University of Hawai'i (Manoa)
Prof. Jack Fell, Rosenstiel School of Marine and Atmospheric Science, University of Miami

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Jensen PR & W Fenical (2002) Secondary metabolites from marine fungi. In: Hyde KD (ed) Fungi in Marine Environments. Fungal Diversity Research Series 7:293-315