Screening for Toxic Compounds in the Red Tide Dinoflagellate Cochlodinium polykrikoides: Is It Toxic Plankton?

Algae > Volume 16(4); 2001 > Article

Algae 2001;16(4): 457-462.

Chang Sook Kim, Sam Geun Lee, Hak Gyoon Kim, Jong Soo Lee

Harmful Algal Blooms Research Division, National Fisheries Research and Development Institute, Department of Marine Food Science and Technology, Gyeongsang National University

ABSTRACT

In order to confirm the existence of ichthyotoxins in the red tide dinoflagellate Cochlodinium polykrikoides, screening for toxins in the extracts of this cells was conducted by a various bioassay systems and HPLC analysis. The aqueous and lipid-soluble fractions of Cochlodinium extracts did not showed toxicity against mice and fish. In addition, ichthyotoxicity was also not observed in the C. polykrikoides-free media. particularly, no effects of algal extracts on the growth of lymphoid cells as well as the mammalian mitochondrial respiration were observed. Even through hemolytic activity was detected in lipid-soluble fractions of C. polykrikoides (>100 ㎍?ml-1), however, this activity was also appeared in the extracts of the Heterosigma akashiwo which is a well-known non-toxic algae. Moreover, these hemolytic compounds-mediated toxic effects such as fish kill were not found. In the PSP analysis by the fluorometric HPLC system, the test samples showed peaks indistinguishable from the standard toxins, but all of them were regarded as false peaks by the HPLC systems, without an oxidaizing reagents. These results suggest that the mechanism of fish kill by a live C. polykrikoides is distinct from the special ichthyotoxic compounds-mediated effects and C. polykrikoides is one of the non-toxic dinoflagellates.

Key words: Cochlodinium polykrikoides, hemolytic activity, PSP, red tide, toxicity