title: Dietary consumption of monosodium L-glutamate induces adaptive response and reduction in the life span of Drosophila melanogaster.
abstract: Adaptive response is the ability of an organism to better counterattack stress-induced damage in response to a number of different cytotoxic agents. Monosodium L-glutamate (MSG), the sodium salt of amino acid glutamate, is commonly used as a food additive. We investigated the effects of MSG on the life span and antioxidant response in Drosophila melanogaster (D. melanogaster). Both genders (1 to 3 days old) of flies were fed with diet containing MSG (0.1, 0.5, and 2.5-g/kg diet) for 5 days to assess selected antioxidant and oxidative stress markers, while flies for longevity were fed for lifetime. Thereafter, the longevity assay, hydrogen peroxide (H2O2), and reactive oxygen and nitrogen species levels were determined. Also, catalase, glutathione S-transferase and acetylcholinesterase activities, and total thiol content were evaluated in the flies. We found that MSG reduced the life span of the flies by up to 23% after continuous exposure. Also, MSG increased reactive oxygen and nitrogen species and H2O2generations and total thiol content as well as the activities of catalase and glutathione S-transferase in D. melanogaster (P < .05). In conclusion, consumption of MSG for 5 days by D. melanogaster induced adaptive response, but long-term exposure reduced life span of flies. This study may therefore have public health significance in humans, and thus, moderate consumption of MSG is advocated by the authors.
authors.affiliation: Drug Metabolism and Molecular Toxicology Research Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria.
authors.forename: Amos O
authors.identifier: http://orcid.org/0000-0002-4203-452X
authors.initials: AO
authors.lastname: Abolaji
authors.affiliation: Nutritional and Industrial Biochemistry Research Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria.
authors.forename: Charles O
authors.initials: CO
authors.lastname: Olaiya
authors.affiliation: Department of Biochemistry, Adekunle Ajasin University, Akungba-Akoko, Ondo State, Nigeria.
authors.forename: Oluwagbenga J
authors.initials: OJ
authors.lastname: Oluwadahunsi
authors.affiliation: Drug Metabolism and Molecular Toxicology Research Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria.
authors.forename: Ebenezer O
authors.initials: EO
authors.lastname: Farombi
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000222:Adaptation, Physiological / Q000187:drug effects*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004032:Diet; D004331:Drosophila melanogaster / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D005421:Flavoring Agents / Q000494:pharmacology*; D005982:Glutathione Transferase / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D012970:Sodium Glutamate / Q000494:pharmacology*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005421:Flavoring Agents; D013438:Sulfhydryl Compounds; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D000110:Acetylcholinesterase; D012970:Sodium Glutamate
keywords: Drosophila melanogaster; adaptive response; antioxidant response; longevity; monosodium L-glutamate; oxidative stress