OEAS Seminar 3/21/13
The Department of Ocean, Earth, and Atmospheric Sciences invites you to attend its weekly seminar series. Dr. Allen Place from the University of Maryland will present “Karlodinium veneficum—The little dinoflagellate with a big bite.” Please join us at 3pm in the Oceanography Building (OCNPS) Room 200, Thursday, March 21st, 2013. All are welcome to attend.
For decades, high densities of the dinoflagellate Karlodinium veneficum have been associated with aquatic faunal mortalities worldwide. This small (<8–12 mm) athecate phytoplankton, common in coastal aquatic ecosystems, has a mixed nutritional mode, relying on both photosynthesis and phagotrophy for growth (mixotrophy). It is frequently present in relatively low cell abundance (102–103 cells mL1), but is capable of forming intense blooms of 104–105 cells mL1 that are often associated with fish kills. A suite of toxic compounds (karlotoxins) have been characterized, both in the laboratory and in the field, with hemolytic, ichthyotoxic, and cytotoxic properties. These toxins have been shown to generate pores in membranes with desmethyl sterols and increase the ionic permeability resulting in membrane depolarization, disruption of motor functions, osmotic cell swelling and lysis. The biological raison d’etre for karlotoxin production appears to be prey capture but grazing deterrence is an additional advantage. Strain variation in types of karlotoxins and toxin cell quotas is extensive. Since its initial description in 1956 by Dorothy Ballentine toxic and nontoxic strains are common. Despite numerous name changes it is now clearly recognized as a cosmopolitan species with extensive ecosystem impacts.
Posted By: Donna Sellers
Date: Mon Mar 18 11:11:07 EDT 2013