Toxic dinoflagellates bloom sporadically in coastal waters throughout the world, often causing outbreaks of paralytic shellfish poisoning (PSP). The recurrent economic and public health impacts of these blooms range from human illness and death to extensive quarantine of shellfish resources. Although the chemical structure and pharmacological activity of the PSP toxins are well understood, their metabolic role within the dinoflagellate remains unknown, as are the factors that cause variability in toxicity between isolates from different regions or in one isolate under different growth conditions. Within the context of a regional population of Alexandrium (formerly Gonyanulax) species, Dr. Anderson will continue investigations in four general research areas. Specifically, he will examine: a) the dynamics of toxin production with major emphasis on the link we are now hypothesizing between toxin production and the dinoflagellate cell cycle; b) the physiology of toxin production, through studies on the causes and effects of elevated free arginine concentrations in the cell and identification of proteins involved in toxin synthesis; c) toxin localization and function through immunocytochemical studies at the ultrastructural level and efforts to purify and characterize a saxitoxin-binding complex from the dinoflagellate nucleus; and d) population comparisons through mating studies and development of molecular methods to discriminate between closely-related isolates of Alexandrium.
