title: Effect of microcystin on ion regulation and antioxidant system in gills of the estuarine crab Chasmagnathus granulatus (Decapoda, Grapsidae).
abstract: The objective of this work was to evaluate mechanisms of microcystin toxicity on crustacean species. Adult male crabs of Chasmagnathus granulatus (13.97+/-0.35 g) acclimated to low salinity (2 per thousand ) were injected with saline (control) or Microcystis aeruginosa aqueous extract (39.2 microg/l) at 24 h intervals for 48 h. After the exposure period, the anterior and posterior gills were dissected, measuring Na(+),K(+)-ATPase and glutathione-S-transferase (GST) activity. Total oxyradical scavenging capacity (TOSC) and lipid peroxides (LPO) content were also determined. Na(+),K(+)-ATPase activity in anterior gills was significantly lower in crabs injected with toxin than in control crabs, while no significant difference in the enzyme activity was detected in posterior gills. Both sodium and chloride concentration in the hemolymph were not affected by toxin exposure. Significant changes in GST activity were detected in posterior gills, with higher values being observed in the toxin-injected crabs. Crabs exposed to microcystin also showed a significant increase in the TOSC value against peroxyl radicals, for both anterior and posterior gills. Lipid peroxides level did not change in both gill types after exposure to the toxin. The increased levels of TOSC suggest the occurrence of a crab response against oxidative stress induced by toxin injection, which prevents lipid peroxidation.
authors.affiliation: Departamento de Ciências Fisiológicas, Fundação Universidade Federal do Rio Grande, R. Eng. Alfredo Huch 475 (96201-900), Rio Grande, RS, Brazil.
authors.forename: T M
authors.initials: TM
authors.lastname: Vinagre
authors.forename: J C
authors.initials: JC
authors.lastname: Alciati
authors.forename: F
authors.initials: F
authors.lastname: Regoli
authors.forename: R
authors.initials: R
authors.lastname: Bocchetti
authors.forename: J S
authors.initials: JS
authors.lastname: Yunes
authors.forename: A
authors.initials: A
authors.lastname: Bianchini
authors.forename: J M
authors.initials: JM
authors.lastname: Monserrat
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D033364:Decapoda / Q000502:physiology*; D016166:Free Radical Scavengers / Q000378:metabolism; D005880:Gills / Q000187:drug effects* / Q000201:enzymology; D005982:Glutathione Transferase / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D052998:Microcystins; D018384:Oxidative Stress / Q000187:drug effects; D010456:Peptides, Cyclic / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D007473:Ion Channels; D052998:Microcystins; D010456:Peptides, Cyclic; D017382:Reactive Oxygen Species; C078588:microcystin; D005982:Glutathione Transferase; D000254:Sodium-Potassium-Exchanging ATPase