DEGRADATION OF THE CYANOBACTERIAL HEPATOTOXIN, NODULARIN, UNDER LIGHTAND DARK CONDITIONS

The stability of the cyanobacterial hepatotoxin, nodularin, was determ ined during the incubation of purified toxin, and in nodularin-contain ing cell-free extracts and whole filaments of the nodularin-producer, Nodularia spumigena in sunlight and darkness; Levels of purified nodul arin in aqueous solution remained approximately constant throughout th e 9-day trials under all conditions, but decreased in cell-free extrac ts and whole filaments when incubated under all conditions, with losse s being greatest in full sunlight, intermediate in sunlight minus ultr aviolet wavelengths and lowest in continuous darkness. Photodegradatio n and detoxification in Artemia salina bioassays occurred when purifie d nodularin was irradiated with ultraviolet wavelengths using a labora tory lamp.