GENERATION OF SUPEROXIDE ANION-RADICALS BY THE MARINE-PHYTOPLANKTON ORGANISM, CHATTONELLA-ANTIQUA

The generation of superoxide anion radical (O2-), believed to be a causative factor in the killing of fish by the phytoplankton Chattonella antiqua, has been examined using several methods: electrochemical technique, reduction of ferricytochrome c and fluorescent laser microscope. Evidence is presented to suggest that these organisms release superoxide continuously while they are living, even in the resting state. Additional generation of O2- accompanies the discharge of mucocysts, and is triggered when they are exposed to mucus from the gill lamellae of fish. Such instantaneous generation of O2- is also induced when the organisms are in contact with an electrode poised at a potential of +0.1 V versus Ag/AgCl. which is positive enough to oxidize O2- to O2.