ACUTE TOXIC EFFECTS OF A NOVEL CYANOBACTERIAL TOXIN ON THE CRUSTACEANS ARTEMIA-SALINA AND DAPHNIA-PULEX

A strain of the cyanobacterium Oscillatoria agardhii non-toxic to mice was toxic to the crustaceans Daphnia pulex and Artemia salina. The 48 h EC(50)-value of a water extract to D. pulex corresponded to 0.26 mg /ml of freeze-dried cyanobacteria, and the 48 h EC(50)-value of a semi -purified, freeze-dried, water extract was 0.06 mg/ml. Whole cells wer e also toxic, but no clear dose-effect relationship could be establish ed, probably because the feeding of the animals was inhibited. The tox ic effect on D. pulex was reversible. Further purification of the toxi n was achieved using gel filtration. A subsequent testing of the toxic ity of the gel filtration fractions, using both species of crustaceans , suggests that a single compound caused the observed toxicity. The mo lecular weight of this toxin was around 2,000, as detected during gel filtration.