title: Phenotypic Plasticity, Epigenetic or Genetic Modifications in Relation to the Duration of Cd-Exposure within a Microevolution Time Range in the Beet Armyworm.
abstract: In the case of the pests inhabiting metal polluted or fields where the use of pesticides is common, a natural selection of resistant individuals can occur. This may pose serious problems for humans, agriculture, as well as the economies of many countries. In this study, the hypothesis that multigenerational (120 generations) exposure to cadmium of a beet armyworm population could be a selecting factor toward a more efficient DNA protection was verified. The hemocytes of individuals from two culture strains (control and Cd-exposed) were treated with H2O2 (a DNA-damaging agent) or PBS (reference). The level of DNA damage was assessed using the Comet assay immediately and 5, 15 and 30 min. after the treatment. The immediate result of the contact with H2O2 was that the level of DNA damage in the hemocytes of the insects from both strains increased significantly. However, in the cells of the Cd-exposed individuals, the level of DNA damage decreased over time, while in the cells from the control insects it remained at the same level with no evidence of repair. These results suggest that efficient defense mechanisms may exist in the cells of insects that have prolonged contact with cadmium. Some evolutionary and trade-off aspects of the phenomenon are discussed. In a wider context, comparing the results obtained in the laboratory with field studies may be beneficial for understanding basic mechanisms of the resistance of an organism. To summarize, the high potential for the repair of DNA damage that was observed in the insects from the cadmium strain may confirm the hypothesis that multigenerational exposure to that metal may possibly contribute to the selection of insects that have a wider tolerance to oxidative stress. However, our investigations of polymorphism using AFLP did not reveal differences between the two main insect strains.
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Augustyniak
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Płachetka-Bożek
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Alina
authors.initials: A
authors.lastname: Kafel
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Babczyńska
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Tarnawska
authors.affiliation: Department of Genetics, University of Silesia, Katowice, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Janiak
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Loba
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Dziewięcka
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Julia
authors.initials: J
authors.lastname: Karpeta-Kaczmarek
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Katowice, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Zawisza-Raszka
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D027461:Beta vulgaris / Q000469:parasitology; D005075:Biological Evolution; D002104:Cadmium / Q000633:toxicity*; D004249:DNA Damage / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D044127:Epigenesis, Genetic / Q000187:drug effects; D006434:Hemocytes / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007313:Insecta / Q000187:drug effects* / Q000235:genetics; D007814:Larva / Q000187:drug effects / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects
chemical_list: D004785:Environmental Pollutants; D002104:Cadmium; D006861:Hydrogen Peroxide