title: Effects of chitosan on oxidative stress and metallothioneins in aquatic worm Tubifex tubifex (Oligochaeta, Tubificidae).
abstract: Chitosan is a natural polymer which has the property to elicit the natural defenses mechanism in plant and which can be an interesting biopesticides. It is then necessary to investigate the potential toxicity of chitosan for aquatic animal health. Metallothioneins (MTs) are low molecular weight proteins, mainly implicated in metal ion detoxification. Increase in MTs contents had been considered as a specific biomarker of metal exposure. However recently it has been demonstrated that MTs participate in several cellular functions such as regulation of growth and anti-oxidative defenses. Therefore, the induction of MTs has been investigated in the aquatic worms Tubifex tubifex exposed to chitosan. MTs levels in exposed worm increased significantly (p > 0.05) after 2, 4, and 7 days of exposure to different concentrations of chitosan (maximum + 158.19 +/- 10.2% after 2 days of exposure to 125 mgl(-1) of chitosan). Several antioxidant parameters including glutathione (GSH), glutathione-S-transferase (GST), glutathione reductase (GR), and catalase (CAT) were quantified in T. tubifex after 2, 4, and 7 days of exposure to chitosan. Exposure to chitosan had a negative effect on T. tubifex growth (maximum effect -6.11 +/- 1.6% after 7 days with 125 mgl(-1)) demonstrating the toxic effect of the pesticide. This growth rate decrease was accompanied by a reduction in protein contents. The activity of catalase (CAT), glutathione-S-transferase (GST), and glutathione reductase (GR) increased in response to the chitosan demonstrating an oxidative stress in the worms.
authors.affiliation: Laboratoire d'Eco-Toxicologie, Unité de Recherche sur la Vigne et le Vin de Champagne, UPRES-EA 2069 Faculté des Sciences, Université de Reims Champagne-Ardenne, B.P. 1039, 51687 Reims cedex 02, France. yaiha.mosleh@voila.fr
authors.forename: Yahia Y
authors.initials: YY
authors.lastname: Mosleh
authors.forename: Séverine
authors.initials: S
authors.lastname: Paris-Palacios
authors.forename: Mohamed T
authors.initials: MT
authors.lastname: Ahmed
authors.forename: F M
authors.initials: FM
authors.lastname: Mahmoud
authors.forename: M A
authors.initials: MA
authors.lastname: Osman
authors.forename: Sylvie
authors.initials: S
authors.lastname: Biagianti-Risbourg
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry / Q000633:toxicity*; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism*; D015394:Molecular Structure; D009835:Oligochaeta / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D014876:Water Pollution / Q000032:analysis
chemical_list: D048271:Chitosan; D008668:Metallothionein; D002374:Catalase; D005980:Glutathione Reductase; D005982:Glutathione Transferase