title: Stress response in two strains of the aquatic hyphomycete Heliscus lugdunensis after exposure to cadmium and copper ions.
abstract: Biochemical responses to cadmium (Cd2+) and copper (Cu2+) exposure were compared in two strains of the aquatic hyphomycete (AQH) Heliscus lugdunensis. One strain (H4-2-4) had been isolated from a heavy metal polluted site, the other (H8-2-1) from a moderately polluted habitat. Conidia of the two strains differed in shape and size. Intracellular accumulation of Cd2+ and Cu2+ was lower in H4-2-4 than in H8-2-1. Both strains synthesized significantly more glutathione (GSH), cysteine (Cys) and gamma-glutamylcysteine (gamma-EC) in the presence of 25 and 50 microM Cd2+, but quantities and rates of synthesis were different. In H4-2-4, exposure to 50 microM Cd2+ increased GSH levels to 262% of the control; in H8-2-1 it increased to 156%. Mycelia of the two strains were analysed for peroxidase, dehydroascorbate reductase, glutathione reductase and glucose-6-phosphate dehydrogenase. With Cd2+ exposure, peroxidase activity increased in both strains. Cu2+ stress increased dehydroascorbate reductase activity in H4-2-4 but not in H8-2-1. Dehydroascorbate reductase and glucose-6-phosphate dehydrogenase activities progressively declined in the presence of Cd2+, indicating a correlation with Cd2+ accumulation in both strains. Cd2+ and Cu2+ exposure decreased glutathione reductase activity.
authors.affiliation: Department of Biochemistry/Biotechnology, Division of Ecological and Plant Biochemistry, Martin-Luther-University, Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle/Saale, Germany.
authors.forename: Bianca
authors.initials: B
authors.lastname: Braha
authors.forename: Herbert
authors.initials: H
authors.lastname: Tintemann
authors.forename: Gudrun
authors.initials: G
authors.lastname: Krauss
authors.forename: Jim
authors.initials: J
authors.lastname: Ehrman
authors.forename: Felix
authors.initials: F
authors.lastname: Bärlocher
authors.forename: Gerd-Joachim
authors.initials: GJ
authors.lastname: Krauss
mesh_terms: D002104:Cadmium / Q000378:metabolism / Q000494:pharmacology*; D003300:Copper / Q000378:metabolism / Q000494:pharmacology*; D003545:Cysteine / Q000378:metabolism; D004151:Dipeptides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006999:Hypocreales / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010088:Oxidoreductases / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D013045:Species Specificity; D013997:Time Factors
chemical_list: D004151:Dipeptides; D002104:Cadmium; D003300:Copper; D010088:Oxidoreductases; D005954:Glucosephosphate Dehydrogenase; D009195:Peroxidase; D005980:Glutathione Reductase; C020666:glutathione dehydrogenase (ascorbate); D005978:Glutathione; D003545:Cysteine; C017341:gamma-glutamylcysteine