title: Antioxidant mechanisms of the Nereidid Laeonereis acuta (Anelida: Polychaeta) to cope with environmental hydrogen peroxide.
abstract: Hydrogen peroxide (H(2)O(2)) is a naturally occurring prooxidant molecule, and its effects in the macroinvertebrate infauna were previously observed. The existence of a gradient of antioxidant enzymes activity (catalase [CAT], glutathione peroxidase [GPx], superoxide dismutase [SOD], and glutathione-S-transferase [GST]) and/or oxidative damage along the body of the estuarine polychaeta Laeonereis acuta (Polychaeta, Nereididae) was analyzed after exposure to H(2)O(2). Because this species secretes conspicuous amounts of mucus, its capability in degrading H(2)O(2) was studied. The results suggest that L. acuta deal with the generation of oxidative stress with different strategies along the body. In the posterior region, higher CAT and SOD activities ensure the degradation of inductors of lipid peroxidation such as H(2)O(2) and superoxide anion (O(2)(.-)). The higher GST activity in anterior region aids to conjugate lipid peroxides products. In the middle region, the lack of high CAT, SOD, or GST activities correlates with the higher lipid hydroperoxide levels found after H(2)O(2) exposure. Ten days of exposure to H(2)O(2) also induced oxidative stress (lipid peroxidation and DNA damage) in the whole animal paralleled by a lack of CAT induction. The mucus production contributes substantially to H(2)O(2) degradation, suggesting that bacteria that grow in this secretion provide this capability.
authors.affiliation: Departamento de Ciencias Fisiologicas, Fundacao Universidade Federal do Rio Grande, Avenida Italia, Km 8, Rio Grande, Rio Grande do Sul 96201-900, Brazil.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: da Rosa
authors.forename: Mariana G
authors.initials: MG
authors.lastname: Iurman
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Abreu
authors.forename: Laura A
authors.initials: LA
authors.lastname: Geracitano
authors.forename: Jose M
authors.initials: JM
authors.lastname: Monserrat
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D002374:Catalase / Q000378:metabolism; D020552:Comet Assay; D004249:DNA Damage / Q000502:physiology; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D009093:Mucus / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D011077:Polychaeta / Q000201:enzymology* / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase