ABSTRACT
The scientific investigation of freshwater cyanobacterial neurotoxins is a relatively new and exciting field of study which already has provided some very interesting surprises (see refs. 1-5). In particular, the first cyanobacterial neurotoxins were isolated from Aphanizomenon flosaquae and were called aphantoxins (6). However, subsequent studies (7-9) have shown that the neurotoxins produced by this species and other cyanobacteria were paralytic shellfish poisons (PSPs) and include saxitoxin, neosaxitoxin, C-toxins, and gonyautoxins (10-13). The freshwater cyanobacteria that are known to produce PSPs include Aphanizomenon flos-aquae (7-9), Anabaena circinalis (11, 12, 14), and Lyngbya wollei (15). Thus, it has become clear that the PSPs found in freshwater cyanobacteria are the same as those found in the marine dinoflagellates that cause toxic red tides.
