Post on 30-Jun-2015
description
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