Evidence for saxitoxins production by the cyanobacterium Aphanizomenon gracile in a French recreational water body

摘要: Abstract In the last few years, a scientific consensus has emerged regarding increasing frequency and severity of cyanobacterial blooms in freshwater environments. Consequently, recreational drinking water bodies are now increasingly monitored by local authorities to prevent animal human poisoning related cyanobacteria their toxins. A survey body used for activities (at Champs-sur-Marne, Paris suburb) was conducted from 2005 2008. The chlorophyll concentrations, occurrence toxic cyanotoxins microcystins, anatoxin-a saxitoxins were recorded. potentially genera Aphanizomenon , Planktothrix Microcystis observed throughout monitoring period. dominant genus during first two years (2005–2007), whereas became towards end (2007–2008). As consequence, microcystins initially detected at high concentrations (max. = 89 μg equiv MC-LR L −1 raw water), later superceded (STXs) Using LC–MS/MS Neuro-2a cell-based assay, we confirmed that STX neoSTX variants present natural samples higher than 3 μg equiv STX L water. To attribute STXs production appropriate taxa, monoclonal cultures obtained after an isolation procedure then screened presence sxt gene. SxtA -positive strains analyzed content using assay LC–MS/MS. results led consider gracile as most likely producer STXs. description French lead discuss health risks associated with alone or its co-occurrence other known bodies.