title: Genotoxicity in Oreochromis niloticus (Cichlidae) induced by Microcystis spp bloom extract containing microcystins.
abstract: Studies of genotoxicity in fish caused by cyanobacterial extracts containing microcystins (MCs) can be useful in determining their carcinogenic risk due to a genotoxic mechanism. An extract of cyanobacterial Microcystis ssp, containing MC-LR and -LA from a bloom collected in a eutrophic lake, showed genotoxicity to Oreochromis niloticus. DNA damage (comet assay) was significantly induced in peripheral erythrocytes with both tested concentrations of 6.90 μg kg(-1) bw and 13.80 μg kg(-1) bw through intraperitoneal injection (ip). There was no micronucleus induction after ip injection at concentrations of 6.90 μg kg(-1) bw and 13.80 μg kg(-1) bw. Body exposure resulted in micronucleus induction and DNA damage only at the highest tested concentrations of 103.72 μg L(-1). Thus, comet assay and ip injection revealed the highest levels of the genotoxicity of MCs. Apoptosis-necrosis test carried out at concentrations of 6.90 μg kg(-1) bw and 13.80 μg kg(-1) bw revealed that at low concentrations more apoptosis than necrosis occurred. At higher concentrations more necrosis than apoptosis occurred.
authors.affiliation: Laboratório de Genética Toxicológica, Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasília, 70910-900 Brasília - DF, Brazil.
authors.forename: R R Pavan
authors.initials: RR
authors.lastname: da Silva
authors.forename: O R
authors.initials: OR
authors.lastname: Pires
authors.forename: C K
authors.initials: CK
authors.lastname: Grisolia
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D023681:Cichlids / Q000235:genetics*; D004249:DNA Damage; D052998:Microcystins / Q000633:toxicity*; D046931:Microcystis / Q000737:chemistry / Q000472:pathogenicity*; D048629:Micronuclei, Chromosome-Defective; D009152:Mutagenicity Tests; D009336:Necrosis
chemical_list: D052998:Microcystins