ABSTRACT
The four orders of the division Cyanophyta (cyanobacteria) (1-5) include several freshwater or brackish water species or strains which produce potent hepatotoxins such as microcystins and nodularins (6, 7), related monocyclic peptides, and cylindrospermopsin (8), a guanidine alkaloid (Table 1). Acute and chronic hazards presented by these toxins to human and animal health are now ranked among the most urgent and serious problems associated with surface water supplies all over the world (for review, see refs. 6, 9, and 10).
