Progress in Understanding Algal Bloom-Mediated Fish Kills: The Role of Superoxide Radicals, Phycotoxins and Fatty Acids

摘要: Quantification of the role reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An vitro gill (from rainbow trout Oncorhynchus mykiss) assay was used to simultaneously assess effect superoxide dismutase, catalase lactate dehydrogenase enzymatic activities caused seven species ichthyotoxic (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum). production these algae also performed. The purified crude extracts compared, is discussed. raphidophyte Chattonella most (gill cell viability down 35%) major producer radicals (14 pmol cell-1 hr-1) especially after lysis. dinoflagellate were least toxic had low production, except when A. catenella lysed (5.6 hr-1). Catalase showed no changes activity all treatments. Superoxide dismutase (SOD) exhibited significant increases ≤23% 51.2% TCC (total cellular content), respectively, exposure C. but SOD insignificant with remaining algal species. A strong relationship between or not observed. Purified brevetoxins PbTx-2 -3 brevis, LC50 22.1 versus 35.2 μg mL-1) karlotoxin KmTx-2 Karlodinium; = 380 ng could almost entirely account for killing those two dinoflagellates. However, paralytic shellfish toxins (PST) GTX1&4, C1&C2, STX did ichthyotoxicity. Only aqueous cytotoxic (≤65% decrease viability), whereas methanol acetone Chattonella, Fibrocapsa, Heterosigma, decreased 0%. These our previous findings involving confirm that are only partially involved ichthyotoxicity point a highly variable contribution other compounds such as lipid peroxidation products (e.g. aldehydes).