title: Mixture toxicity of microcystin-LR, paraoxon and bromadiolone in Xenopus laevis embryos.
abstract: OBJECTIVE
  Apart from infections and habitat loss, environmental pollution is another major factor of global decline of amphibians. Using the model of Xenopus laevis embryos, we test the hypothesis that combined exposure of amphibians to natural toxins and anthropogenic pollutants induces more pronounced adverse effects than single exposures.
  
  
  METHODS
  Experimental procedures adhered to Frog Embryo Teratogenesis Assay - Xenopus standards (FETAX). Exposure groups included controls, solvent (dimethyl sulfoxide) controls, and embryos exposed for 96 h to single, double and triple action of paraoxon (P), bromadiolone (B), and microcystin-LR (M), added to the FETAX medium at a dose of 300, 350, and 500 μg.L(-1), respectively. Studied responses of X. laevis embryos included mortality and malformations, head-to-tail length, total antioxidant capacity, lipid peroxidation, and caspase-3 activity.
  
  
  RESULTS
  The triple combination induced the highest mortality. Malformations in embryos significantly prevailed only in B-, and B+P-exposure groups. Apart from the single exposure to B, the tested substances and their combinations inhibited the embryonic growth. Triple exposure had the most pronounced effect both on the growth inhibition and total antioxidant capacity. Lipid peroxidation was increased after B+M exposure, while single and combined exposures to B and P had an opposite effect.
  
  
  CONCLUSIONS
  This study helps to understand adverse effects of environmental pollution by natural toxins and agrochemicals in amphibians. The results allow for risk assessment of environmental pollution and findings of low concentrations of contaminants in aquatic environments. Further research to address issues such as mixture toxicity to metamorphosing and adult amphibians is necessary.
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Ondracek
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Bandouchova
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic.
authors.forename: Klara
authors.initials: K
authors.lastname: Hilscherova
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Kovacova
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Linhart
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Miksikova
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Mlcakova
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Jitka
authors.initials: J
authors.lastname: Osickova
authors.affiliation: Center of Advanced Studies, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Pohanka
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Skochova
authors.affiliation: Department of Ecology and Diseases of Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Pikula
mesh_terms: D015110:4-Hydroxycoumarins / Q000633:toxicity*; D000014:Abnormalities, Drug-Induced; D000818:Animals; D000925:Anticoagulants / Q000633:toxicity*; D049628:Body Size / Q000187:drug effects; D053148:Caspase 3 / Q000187:drug effects; D002800:Cholinesterase Inhibitors / Q000633:toxicity*; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000196:embryology; D004791:Enzyme Inhibitors / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects*; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D010261:Paraoxon / Q000633:toxicity*; D018675:Toxicity Tests; D014982:Xenopus laevis / Q000196:embryology
chemical_list: D015110:4-Hydroxycoumarins; D000925:Anticoagulants; D002800:Cholinesterase Inhibitors; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D053148:Caspase 3; C057862:cyanoginosin LR; C021636:bromadiolone; D010261:Paraoxon