title: The induction of menadione stress tolerance in the marine microalga, Dunaliella viridis, through cold pretreatment and modulation of the ascorbate and glutathione pools.
abstract: The effect of cold pretreatment on menadione tolerance was investigated in the cells of the marine microalga, Dunaliella viridis. In addition, the involvement of ascorbate and glutathione in the response to menadione stress was tested by treating cell suspensions with l-galactono-1,4-lactone, an ascorbate precursor, and buthionine sulfoximine, an inhibitor of glutathione synthesis. Menadione was highly toxic to non cold-pretreated cells, and caused a large decrease in cell number. Cold pretreatment alleviated menadione toxicity and cold pretreated cells accumulated lower levels of reactive oxygen species, and had enhanced antioxidant capacity due to increased levels of β-carotene, reduced ascorbate and total glutathione compared to non cold-pretreated cells. Cold pretreatment also altered the response to l-galactono-1,4-lactone and buthionine sulfoximine treatments. Combined l-galactono-1,4-lactone and menadione treatment was lethal in non-cold pretreated cells, but in cold-pretreated cells it had a positive effect on cell numbers compared to menadione alone. Overall, exposure of Dunaliella cells to cold stress enhanced tolerance to subsequent oxidative stress induced by menadione.
authors.affiliation: Department of Biology, Lorestan University, Khoramabad-Tehran Road (5(th) K), Iran. Electronic address: madadkar.m@lu.ac.ir.
authors.forename: Maryam
authors.initials: M
authors.lastname: Madadkar Haghjou
authors.affiliation: Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK.
authors.forename: Louise
authors.initials: L
authors.lastname: Colville
authors.affiliation: University of Exeter, School of Biosciences, Geoffrey Pope Building, Exeter EX4 4QD, UK.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Smirnoff
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D000460:Chlorophyta / Q000187:drug effects* / Q000378:metabolism*; D003080:Cold Temperature; D005978:Glutathione / Q000378:metabolism*; D007783:Lactones / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D013400:Sugar Acids / Q000494:pharmacology; D024483:Vitamin K 3 / Q000494:pharmacology*
chemical_list: D007783:Lactones; D013400:Sugar Acids; C534014:galactono-1,4-lactone; D019328:Buthionine Sulfoximine; D024483:Vitamin K 3; D005978:Glutathione; D001205:Ascorbic Acid
keywords: Ascorbate; Cold pretreatment; Dunaliella viridis; Glutathione; Menadione; Oxidative stress