Assessment of Environmental Conditions That Favor Hepatotoxic and Neurotoxic Anabaena spp. Strains Cultured under Light Limitation at Different Temperatures
Assessment of Environmental Conditions That Favor Hepatotoxic and Neurotoxic Anabaena spp. Strains Cultured under Light Limitation at Different Temperatures
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DOI：
10.1007/s002489900105
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发表时间：
1998-09
影响因子：
3.6
通讯作者：
J. Rapala;K. Sivonen
中科院分区：
文献类型：
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作者：
J. Rapala;K. Sivonen
AbstractToxic cyanobacterial mass occurrences have caused animal poisonings worldwide and may pose a health hazard for humans. Strains of the genusAnabaenaare either non-toxic or produce hepatotoxins, microcystins (MCYST), or neurotoxins (such as anatoxin-a). In order to study which growth conditions favor hepatotoxic vs neurotoxic strains and how production of toxins varies, we compared the responses of two microcystin- and two anatoxin-a-producingAnabaenastrains 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 and not associated with hepatotoxicity or neurotoxicity. Thus, differential adaptation of strains to temperature and to growth-limiting light levels cannot explain why, in some cyanobacterial water blooms, hepatotoxic strains, and in others, neurotoxic ones become dominant. A statistical analysis of field data showed that the most significant discriminating factors between different types of blooms were the concentrations of dissolved PO4-phosphorus and NO3-nitrogen.Anabaenablooms with unknown neurotoxicity associated with low PO4-phosphorus and high NO3-nitrogen concentrations. Among otherAnabaenablooms, the hepatotoxic ones associated with the lowest, and most of the non-toxic ones with higher concentrations of PO4-phosphorus.Anabaenablooms that contained anatoxin-a and hepatotoxicMicrocystisblooms showed tendencies towards the highest concentrations of PO4-phosphorus. Non-toxic blooms dominated by genera other thanAnabaenaoccurred over a wide range of growth conditions. In turbidostat cultures, maximal production of microcystins correlated with maximal growth rates. Light regulated the production of MCYST-LR variants, and temperature affected the production of MCYST-RR variants. Anatoxin-a seemed to be produced most under temperatures and light levels slightly suboptimal for growth. Under low light, considerable amounts of extracellular anatoxin-a were detected while microcystins consistently remained intracellular.
