Behavioral Toxicology and Pathology of Early Exposure to Toxic PCOsEPA Grant Number: R828224
Title: Behavioral Toxicology and Pathology of Early Exposure to Toxic PCOs
Investigators: Kane, Andrew S. , Little, Edward E.
Current Investigators: Kane, Andrew S. , Salierno, James D.
Institution: University of Maryland - College Park
Current Institution: University of Maryland - College Park , University of Maryland School of Medicine
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2000 through August 30, 2003 (Extended to April 30, 2005)
Project Amount: $423,264
RFA: Ecology and Oceanography of Harmful Algal Blooms (1999) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water , Ecosystems
In recent years, harmful algal blooms (HABs) have increased in frequency, severity and duration worldwide. On the U.S. Atlantic seaboard, there are several species of toxin-producing algae and protists that are implicated with a variety of negative health effects on humans and aquatic and marine organisms. Certain dinoflagellates, including Pfiesteria piscicida and its close relatives (collectively known as organisms of the Pfiesteria complex, or Pfiesteria complex organisms, PCOs), are implicated with effects on human and fish health. In fish, PCO toxin exposure is associated with aberrant behavior and the formation of severe ulcerative lesions. These observations have been noted primarily in menhaden and are also associated with fish kills. At present, the scientific community has little insight into the physiological consequences of fish exposure to bioactive substances released from PCOs or other HAB species, or the effects of exposure on the development of fish ulcerative lesions and mortality. Further, there is no probe currently available to detect PCO toxins. Therefore, we will test two hypotheses: specific, quantifiable behavioral indices are related to different HAB exposures and will be indicative of exposure concentration, substance, and mechanism of action; and pathologic evaluation of controlled laboratory-exposed fish to HAB bioactive compounds, with and without the presence of opportunistic pathogens, will help elucidate the mechanism of lesion initiation and ulcer progression.
This project includes methods for biologically detecting PCO toxin(s) and other HAB toxins, and for evaluating effects PCO toxin exposure to fish relative to skin alterations and ulcer formation. The following hypotheses will be addressed: Ha1: Specific behavioral indices are related to specific PCO toxin and reference toxin exposures; Ha2: Quantifiable behavioral endpoints are valid indices of early PCO/HAB toxin exposure; and Ha3: Pathologic evaluation of controlled laboratory-exposed fish to PCO toxins with and without the presence of opportunistic pathogens will help elucidate the mechanism of lesion initiation and ulcer progression. These hypotheses will be tested by examining behavioral toxicologic endpoints in killifish and menhaden exposed to PCOs and reference HAB toxins. Endpoints will be evaluated using video-based computer analyses. Fish exposed during the behavioral toxicology component of the study will subsequently be pathologically assessed for PCO toxin-specific alterations.
Application of the proposed behavioral endpoints will offer sensitive, biologically-relevant indices of fish exposure to specific HAB toxins. Data from these studies will have application for biological monitoring of waters with low concentrations of different biotoxins and contaminants. The behavioral motion analysis studies will develop species-specific profiles for different stress exposure regimes. Pathology studies will focus on elucidating tissue and cell-level manifestations of biotoxin exposure alone and in combination with naturally occurring, opportunistic pathogens. These integrated data will provide needed insight into the pathogenesis of ulcerative lesions seen on menhaden as well as another fish species (killifish), and help to delineate the roll of PCO toxins in ulcerative lesion initiation.