Assessment of Environmental Conditions That Favor Hepatotoxic and Neurotoxic Anabaena spp. Strains Cultured under Light Limitation at Different Temperatures

摘要: Toxic cyanobacterial mass occurrences have caused animal poisonings worldwide and may pose a health hazard for humans. Strains of the genus Anabaena are either non-toxic or produce hepatotoxins, microcystins (MCYST), neurotoxins (such as anatoxin-a). In order to study which growth conditions favor hepatotoxic vs neurotoxic strains how production toxins varies, we compared responses two microcystin- anatoxin-a-producing in continuous turbidostat cultures, at different temperatures, under growth-limiting light levels. Growth rates consistently remained <0.8 divisions per 24 h. Differences were strain-specific not associated with hepatotoxicity neurotoxicity. Thus, differential adaptation temperature levels cannot explain why, some water blooms, strains, others, ones become dominant. A statistical analysis field data showed that most significant discriminating factors between types blooms concentrations dissolved PO4-phosphorus NO3-nitrogen. unknown neurotoxicity low high NO3-nitrogen concentrations. Among other lowest, higher PO4-phosphorus. contained anatoxin-a Microcystis tendencies towards highest Non-toxic dominated by genera than occurred over wide range conditions. maximal correlated rates. Light regulated MCYST-LR variants, affected MCYST-RR variants. Anatoxin-a seemed be produced temperatures slightly suboptimal growth. Under light, considerable amounts extracellular detected while intracellular.