Grantee Research Project Results

2001 Progress Report: Detection and Identification of the Toxins from Pfiesteria and Related Harmful Algal Blooms

EPA Grant Number: R826655
Title: Detection and Identification of the Toxins from Pfiesteria and Related Harmful Algal Blooms
Investigators: Gawley, Robert E. , Baden, Daniel G.
Institution: University of Miami , University of North Carolina at Chapel Hill
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 1998 through July 31, 2002
Project Period Covered by this Report: August 1, 2000 through July 31, 2001
Project Amount: $353,975
RFA: Ecology and Oceanography of Harmful Algal Blooms (1998) RFA Text | Recipients Lists
Research Category: Water Quality , Nanotechnology , Harmful Algal Blooms , Water , Aquatic Ecosystems

Objective:

This project has three objectives:

Grow cultures of Pfiesteria and related "Shephard's Crook" dinoflagellates (a not-yet-assigned organism that is present in many Pfiesteria outbreaks), as well as Scripsiellas, Glenodiniums, and Gyrodiniums dinoflagellates. Concentrate the toxins on reversed-phase C-18 high performance liquid chromatography columns by filtration of aquarium water, then elute fractions with organic solvents. Identify toxic fractions by whole-fish bioassay using Tilapia fish fry. Purify the toxins to homogeneity, accumulate enough to allow chemical characterization, and elucidate the toxins' structure using mass spectrometry, nuclear magnetic resonance, infrared spectroscopy, and perhaps x-ray crystallography.
Use the techniques of combinatorial chemistry to design ligand-selective host(s) that bind toxins from Pfiesteria and related dinoflagellates, while simultaneously effecting a visible signal of such binding in the form of enhanced fluorescence, seeking a host with optimum response to toxin and minimum response to other possible guests. Because the structures of the toxins are not known, this will be accomplished by seeking a correlation of toxicity in toxic fractions with fluorescence signalling of library members on polymer beads. The most highly fluorescent beads then could be produced in bulk for use as a toxin sensor.
Once hosts that bind the toxin are known, build an affinity column to replace the C-18 column in the aquarium filter, and use this tool to collect the toxin for chemical characterization. This stationary phase also could be used for separating the toxins from other lipophilic components of the toxin extracts. The latter is a prerequisite for work on the biological aspects of these toxins. A large-scale application of this approach might be used in detoxification efforts.

Progress Summary:

Specific Aim 1: Samples of the Pfiesteria organisms and Pfiesteria-like organisms (PLOs) were isolated from estuarine environments from North Carolina, Florida, Maryland, South Carolina, and Delaware. Water samples collected from areas exhibiting active fish kills also were examined for all of the microalgae that were present. From each water sample, clonal cell cultures were obtained, including several non-Pfiesteria specimens. Clones from these isolates were tested against several biological receptors that could be responsible for some of Pfiesteria's neurological effects.

Specific Aim 2: Because we have not yet isolated a toxin from Pfiesteria, we have tested our approach on another dinoflagellate toxin, saxitoxin. We have synthesized and begun testing of 11 potential chemosensors for the dinoflagellate toxin saxitoxin. We have measured binding constants in the range of 104?105 M-1 for some of these sensors. These results will be published as soon as the binding assays are concluded.

Specific Aim 3: This goal is predicated on completion of Specific Aim #2, which is incomplete at this time.

Future Activities:

Testing of 11 potential chemosensors for the dinoflagellate toxin, saxitoxin, will be completed, and the results will be published.

Journal Articles:

No journal articles submitted with this report: View all 9 publications for this project

Supplemental Keywords:

water, watersheds, sediments, marine, estuary, exposure, risk assessment, effects, bioavailability, vulnerability, dose-response, animal, organism, cellular, chemicals, toxics, organics, pathogens, environmental chemistry, biology, ecology, analytical, measurement methods, southeast, Atlantic coast, Chesapeake Bay, North Carolina, NC, Virginia, VA., RFA, Scientific Discipline, Water, Geographic Area, Waste, Ecosystem Protection/Environmental Exposure & Risk, Limnology, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Contaminated Sediments, Chemistry, State, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, algal blooms, Southeast, Biology, Ecological Indicators, East Coast, ecological exposure, pfiesteria piscicida, North Carolina, agricultural runoff, fish kills, Shephard's Crook, whole-fish bioassay, ecology, suburban watersheds, bloom dynamics, harmful algal blooms, Gyrodiniums, economic assessments, fish lesions, ligand sensitive hosts, Everglades, pfiesteria, toxins, environmental chemistry, dinoflagellate, Glenodriniums, Tilapia, bioassay, fluorescence sensing, Virginia, Florida, Scripsiellas

Relevant Websites:

http://www.rsmas.miami.edu/groups/niehs/ (Web site for the University of Miami, NIEHS Marine and Freshwater Biomedical Sciences Center) Exit EPA icon

http://www.uncwil.edu/cmsr/ (Web site for the University of North Carolina at Wilmington, Center for Marine Science Research) Exit EPA icon

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.