ABSTRACT
Mediterranean strains of Prorocentrum minimum do not appear to have the same toxic component as Japanese strains since they showed no cytotoxicity for hepatocytes in culture. However, their toxic components, which appear to block calcium channels, were detectable by the immobilisation test on Diptera larvae. A bio-accumulation experiment in the laboratory showed that the toxins could accumulate in nearly equivalent amounts in the hepatopancreas and meat of cultured mussels. The same toxicity was found in natural samples collected in a period of bloom of P. minimum. These results suggest that P. minimum could be responsible for shellfish toxicity in the natural environment and thus present a risk for human health.
Subject(s)
Bivalvia/drug effects , Dinoflagellida , Marine Toxins/toxicity , Animals , Bivalvia/metabolism , Brain/drug effects , Brain/metabolism , Cells, Cultured , Digestive System/drug effects , Digestive System/metabolism , Diptera/drug effects , Heart/drug effects , Liver/drug effects , Marine Toxins/isolation & purification , Marine Toxins/pharmacokinetics , Mice , Neurotoxins/toxicity , Rana esculenta , Rats , Toxicity TestsABSTRACT
Evolution of the Gambierdiscus toxicus populations during the 1979/1985-1991 period shows an increase of the average densities until 1988-Sept. that seems linked with climatic parameters (insolation, rainfalls) but mainly with anthropogenetic disturbances. After a bloom the populations are now stabilized at a level higher than at the beginning of the monitoring. Without clear correlation, Gtx densities seems associated to physical and chemical features of the lagoonal and reefal waters.
Subject(s)
Dinoflagellida/growth & development , Animals , Cell Count , Ciguatoxins , Cnidaria , Comoros , Dinoflagellida/cytology , Rain , TemperatureABSTRACT
The community of benthic dinoflagellates of Mayotte Island is similar to those of other regions. Four clones of Gambierdiscus toxicus and of other benthic dinoflagellates species (Prorocentrum spp., Ostreopsis sp., Amphidinium spp.) have been isolated and screened for their crude toxicity using mouse-test. The toxigenic reservoir seems moderated. One toxic clone of G. toxicus has been studied for factors governing growth and photosynthetic activity of this species: salinity, temperature, light intensity and nutrients with bioassays.
