Chromosomal Aberrations in Early Embryos of Weatherfish (Misgurnus fossilis L.) Exposed to Crude Cyanobacterial Extract and Semipurified Compound of Microcystins - a Pilot Study

M Palíková,R Krejčí,M Rábová,S Navrátil,L Bláha

doi:10.2754/avb200776s8s055

Abstract

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 (MC-LR: ΣMC= 1: 2.6) and crude cyanobacterial extract (MC-LR: ΣMC= 1: 2.1) both at doses of 130, 50 and 13 μg l-1. 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) increased after the application of higher doses (130 and 50 μg l-1) of crude cyanobacterial extract (p ⪬ 0.05). 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 (p ⪬ 0.05). Embryo mortality was affected especially by crude cyanobacterial extract, therefore other toxic elements than microcystins present in the extract were probably involved.

Highlights

Crude extract of cyanobacteria as well as cyanobacterial toxins themselves may act genotoxically
Though e.g. Hayashi et al (1998), Hose and Brown (1998), Amanuma et al (2000), Diekmann et al (2004) studied genotoxic effects of pollutants to early developmental fish stages, these studies did not include effects of cyanotoxins. In this pilot study we examined the possible genotoxic effect of microcystins and crude extract of cyanobacteria using detection of chromosomal aberrations in the early life stages of weatherfish
In the 52nd hour after fertilization, 15-27% of specimens were already hatched in all groups except the highest concentration of cyanobacterial extract where only 5 specimens were hatched

Summary

Introduction

Crude extract of cyanobacteria as well as cyanobacterial toxins themselves may act genotoxically. Though e.g. Hayashi et al (1998), Hose and Brown (1998), Amanuma et al (2000), Diekmann et al (2004) studied genotoxic effects of pollutants to early developmental fish stages, these studies did not include effects of cyanotoxins. In this pilot study we examined the possible genotoxic effect of microcystins and crude extract of cyanobacteria using detection of chromosomal aberrations in the early life stages of weatherfish. As a model fish species, the weatherfish (Misgurnus fossilis) was chosen due to its habitat preference to stagnant, largely anoxic water bodies where blue green algae bloom frequently

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Conclusion