title: Assessment of oxidative stress and activities of antioxidant enzymes depicts the negative systemic effect of iron-containing fertilizers and plant phenolic compounds in the desert locust.
abstract: For herbivore insects, digesting can be somewhat challenging, as the defense mechanisms evolved by plants, including the release of phenolics like the non-protein amino acid L-3,4-dihydroxyphenylalanine (L-DOPA), can cause fitness costs. In addition, industrial and agricultural activities have elevated the amounts of iron that can be found in nature and more particularly FeSO4that is used as fertilizer. Traces of iron can enhance the auto-oxidation of L-DOPA, in turn, generating reactive oxygen species (ROS) and consequently oxidative stress in insects. We examined the effects of the ion Fe2+(as FeSO4) and L-DOPA on fifth instars of the desert locust Schistocerca gregaria. We measured the level of oxidative damage occurring to macromolecules (proteins and lipids) from midgut and thoracic tissues and assessed the activities of responsive antioxidant enzymes. Injected L-DOPA and redox-active metal iron generated ROS which caused oxidative damages to proteins and lipids to S. gregaria. The protein carbonyls and lipid peroxides present in tissue homogenates were elevated in treated insects. No synergism was observed when L-DOPA was co-injected with Fe2+. Kmvalues of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) were 4.3, 2.6, and 4.0 mM in thoracic muscles and 5.00, 2.43, and 1.66 mM in whole midgut for SOD, GR, and GPx, respectively, and 8.3 and 3.43 M for catalase (CAT) in the two tissues, respectively. These results suggest higher affinities of GPx and CAT to H2O2in midgut than in muscles. The time-course changes in activities of antioxidant enzymes and amounts of protein carbonyls and lipid peroxides showed fluctuating patterns, suggesting complex interactions among macromolecules, L-DOPA and FeSO4, and their degradation products. Our results demonstrated the stressful effects of L-DOPA and FeSO4, proving that iron-containing fertilizers are pollutants that can strongly affect S. gregaria.
authors.affiliation: UMR CNRS 6553, Université de Rennes 1, Avenue du Gal Leclerc, 35042, Rennes Cedex, France. david.renault@univ-rennes1.fr.
authors.forename: David
authors.initials: D
authors.lastname: Renault
authors.affiliation: Department of Entomology, Faculty of Science, Cairo University, P O Box, Giza, 12613, Egypt.
authors.forename: Moataza A
authors.initials: MA
authors.lastname: Dorrah
authors.affiliation: Department of Entomology, Faculty of Science, Cairo University, P O Box, Giza, 12613, Egypt.
authors.forename: Amr A
authors.initials: AA
authors.lastname: Mohamed
authors.affiliation: Department of Entomology, Faculty of Science, Cairo University, P O Box, Giza, 12613, Egypt.
authors.forename: Eman A
authors.initials: EA
authors.lastname: Abdelfattah
authors.affiliation: Department of Entomology, Faculty of Science, Cairo University, P O Box, Giza, 12613, Egypt. taha@sci.cu.edu.eg.
authors.forename: Taha T M
authors.initials: TT
authors.lastname: Bassal
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D005296:Ferrous Compounds / Q000633:toxicity*; D005308:Fertilizers / Q000633:toxicity; D041981:Gastrointestinal Tract / Q000201:enzymology; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006110:Grasshoppers / Q000187:drug effects / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000633:toxicity; D007980:Levodopa / Q000633:toxicity*; D015227:Lipid Peroxidation / Q000187:drug effects; D008054:Lipid Peroxides / Q000378:metabolism; D009132:Muscles / Q000201:enzymology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D010636:Phenols / Q000378:metabolism*; D050050:Protein Carbonylation / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005296:Ferrous Compounds; D005308:Fertilizers; D008054:Lipid Peroxides; D010636:Phenols; D017382:Reactive Oxygen Species; C020748:ferrous sulfate; D007980:Levodopa; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase
keywords: Antioxidant enzymes; Insect; Lipid peroxides; Midgut; Oxidative stress; Protein carbonyls; Thoracic muscles