Bioactive Natural Products from Deep Sea Hydrothermal Vent Organisms

Bioactive Natural Products from Deep Sea Hydrothermal Vent

Organisms

Mark Zabriskie & Kerry McPhail

Department of Pharmaceutical Sciences

Oregon State University

Why Natural Products?

• Best source of chemical diversity and bioactive compounds– ‘Secondary Metabolites’ – function in communication and protection

– Have evolved to potently interact with specific molecular targets• there is a purpose for their existence and biological activity

– ~ 65% of antibacterial and anticancer drugs have a NP origin

• Constant need for new small molecules as drug leads – Increasing drug resistance – esp. infectious diseases and cancer– NPs are best source of chemical diversity and bioactive compounds– Chemical diversity directly correlates with biological diversity

• Screening unique organisms from rare/extreme ecosystems isthe best way to discover novel natural products with important biological activities

Why Deep-sea Hydrothermal Vents?

• Vent systems are a highly unique ecological niche– Organisms have not been examined for bioactive NPs– High likelihood of novel chemistry and bioactivity

• Project builds on relationship with scientists in the NOAA/PMEL Vents program

– Access to samples collected by submersible and ROV– Expands base of researchers working on vent systems– Enhances project portfolio and expands funding opportunities

• Aligns with NOAA’s Ocean Exploration program – Bioprospecting is a research area recommended by the President’s

Advisory Panel on Ocean Exploration.

– The “New Ocean Resources” program encourages diverse sampling

Goals• Primary Goal: Assess potential of deep vent organisms as a source of

novel small molecules for drug discovery

• Specific Aims– Obtain samples of deep vent microbial mats and invertebrates

collected in collaboration with NOAA PMEL/Vents Program researchers

– Create library of extracts, subfractions and pure compounds and evaluate biological activities

• Whole cell assays – cytotoxic, antimicrobial• Inhibition of biofilm formation • in vivo chemical genetics using a Zebrafish model

– Structurally characterize pure bioactive compounds

Source Materials: Archival Samples

• Archived field-collected specimens– Invertebrates – Prof. V. Tunnicliffe (University Victoria)

• Collected at various site in the Juan de Fuca Ridge system

• Tube worms, palm worms, scale worms, limpets, etc.

– Microbial mats – Prof. C. Moyer (Western Washington University)• Push cores and suction samples from Explorer Ridge and Mariana

Island Arc

– Sample size permits testing for activity but not structural studies

Photos: www.pmel.noaa.gov/vents/nemo/explorer/bio_gallery/biogallery

Split limpetTemnocinclis euripes

Tube wormRidgeia piscesae

Palm wormParalvinella palmiformis

bacterial mat

Photo: W. Chadwick

Source Materials: New Collections

• June 2009 cruise to Juan de Fuca Ridge– R/V Atlantis carrying the submersible Alvin

– First time vent organisms gathered specifically for natural product discovery

• Invertebrates and bacterial mats collected– Quantities will permit structural studies

– Culture samples taken for all bacteria

Figure: W. ChadwickPhoto: K. McPhail

Deep Ocean Microbial Diversity

Deep-Sea Bacteria

n = 9,992 sequences

Deep-Sea HydrothermalVent Bacteria

n = 7,641 sequences

Deep-Sea Archaea

n = 1,995 sequences

Deep-Sea HydrothermalVent Archaea

n = 1,686 sequences

Expected Outcomes

• New chemotypes for drug discovery• Chemical probes for pharmacology and cell

biology research• Leverage results to secure federal funding

(NSF/NIH) supporting collection and biodiscovery

• Gain insight into chemical ecology of vent communities

Acknowledgments

• Christopher Thornburg (OSU)

• Bill Chadwick (HMSC/OSU)• Craig Moyer (WWU) • Verena Tunnicliffe (U. Victoria) • David Butterfield (PMEL/UW)

• Jay Rasmussen & John Cassady• Oregon Sea Grant Program

Development Award

Preliminary Results

• Half the archival specimens have been fractionated and tested for biological activity

– Examined antimicrobial activity vs. S. aureus, E. coli and C. albicans– Activity observed for several crude and pre-fractionated extracts

• Majority of activity is antifungal

– Some samples also exhibit modest cytotoxic activity

Preliminary Results

• Initial activity profile for 3 samples from June 2009 cruise

Percent Inhibition

Table X: Activity profile for four microbial mat samples.Prioritized fractions are in bold