Chromosomal aberrations in early embryos of weatherfish (Misgurnus fossilis L.) exposed to crude cyanobacterial extract and semipurified compound of microcystins - a pilot study

The genotoxicity of semipurified compound of microcystins and crude extract of cyanobacteria was analyzed and assessed using detection of chromosomal aberrations in early life stages of weatherfish. For 96 hours, weatherfish eggs at an eye spot stage were exposed to semipurified compound of microcystins and crude cyanobacterial extract both at doses of 130, 50 and 13 microg/L. Hatching time in individual groups and aberrations in the behaviour of hatched specimens were recorded. Cumulative mortality and the proportion of deformed specimens were determined; materials for histological and cytogenetic screening were simultaneously sampled. Cumulative mortality (28 and 26%, respectively) significantly increased after the application of higher doses (130 and 50 microg/L, resp.) of crude cyanobacterial extract. In these groups, hatched embryos showed reduced agility and stayed in clusters and in the group with the highest dose of crude cyanobacterial extract white spots on yolk sacks appeared. Cytogenetic screening revealed both chromatid (gaps) and chromosomal aberrations (rings, dicentrics), percentage of which increased with the increased concentration of microcystins and the higher doses of crude cyanobacterial extract. The highest number of aberrant metaphases was recorded after the application of the highest concentrations of cyanobacterial extract and microcystin. Embryo mortality was affected especially by crude cyanobacterial extract, therefore other toxic elements than microcystins present in the extract were probably involved.