Toxigenic Pfiesteria species—Updates on biology, ecology, toxins, and impacts

摘要: Abstract The genus Pfiesteria includes two toxigenic species, piscicida and shumwayae , that are thinly thecate dinoflagellates with apparently cosmopolitan distribution, especially in shallow, poorly flushed, eutrophic estuaries. They heterotrophic prey generalists typically feed via phagotrophy prefer live fish or their fresh tissues as food. can also engage limited mixotrophy through temporary retention of kleptochloroplasts from algal prey. Toxicity is highly variable among strains, ranging nontoxic to toxic. Some strains produce a group hydrophilic toxins metal-mediated free radical production. Various metals be involved the toxin congeners, purified labile. These adversely affect mammalian cells well fish. Toxic capable killing by both physical attack feeding upon epidermis other tissues. Non-inducible do not sufficient kill fish, but some causing larval death attack. From 1991 1998, spp. were linked major kills juvenile Atlantic menhaden ( Brevoortia tyrannus ), mostly at densities ≥4(3) × 10 2 10 3  (rarely, 4 ) flagellate cells mL −1 . mainly occurred second largest estuaries on U.S. mainland, main tributaries Albemarle-Pamlico Estuarine System, following decades hurricane-free conditions. Between kills, abundance was low surface waters available evidence suggests populations lower water column within surficial sediments. Apparently sensitive scouring effects storms, have been sparse affected since several hurricanes struck late 1990s. Recent research highlights include characterization novel toxins, culture strain sterile cell line, axenic semi-defined medium, discovery new mode manifested advances understanding nutritional ecology acquisition these harmful dinoflagellates.