Abstract
Red tide phytoplankton, Chattonella marina and Heterosigma akashiwo, are known to generate superoxide anion (O2 -). We found that galacturonic acid (GalUA) stimulated C. marina and H. akashiwo to generate increased amounts of O2 -. Since such effect was not observed in any other monosaccharides tested, our results suggest that the binding of GalUA to specific sites on the flagellate cell surface may induce the increase of O2 - production.