SURFACTANT PROMOTION OF THE INHIBITORY EFFECTS OF CUPRIC GLUTAMATE ON THE DINOFLAGELLATE ALEXANDRIUM(1).

We studied cupric glutamate as a novel algicide for marine harmful algae and hexadecyltrimethyleamine bromide (HDTMAB) as an accelerant. Cupric glutamate had an excellent ability to inhibit the growth of Alexandrium sp. LC3, but the inhibition efficiency did not increase with higher cupric glutamate concentration. The studies on the inhibition ofAlexandrium sp. LC3 by cupric sulfate or cupric glutamate showed that cupric glutamate had a higher inhibition rate than cupric sulfate (P < 0.05). HDTMAB could significantly enhance the inhibition by cupric glutamate (P < 0.05). Ultrastructural changes of Alexandrium sp. LC3 under cupric sulfate, cupric glutamate, and cupric glutamate-HDTMAB combined treatment were studied with TEM. Under these stresses, the integrity of the cell plasma membranes (cell plasma membrane, chloroplast and mitochondria membranes) was destroyed. The degree of damage under cupric glutamate-HDTMAB combined treatment was more severe than under the other stresses. These results indicated that mechanistically cupric glutamate inhibits algal growth by destroying the cell membranes, and that HDTMAB promotes this process, which induced mass extravasation of intracellular components and more copper ion entry into the plasma.