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Oxidative stress induced by copper: defense and damage in the marine planktonic diatom Ditylum brightwellii, grown in continuous cultures with high and low zinc levels

1994; Springer Science+Business Media; Volume: 119; Issue: 4 Linguagem: Inglês

10.1007/bf00354321

1432-1793

J. W. Rijstenbil, Jan W. M. Derksen, Loes J. A. Gerringa, T.C.W. Poortvliet, A.J.J. Sandee, M. van den Berg, J. van Drie, Jan Wijnholds,

Geochemistry and Elemental Analysis

Light-limited cultures of the planktonic diatom Ditylum brightwellii (West) Grunow were grown at 14‰ salinity. Cells were subjected to oxidative stress induced by copper, in the presence of zinc. In two continuous cultures with total Zn levels of 40 and 140 nM, respectively, dissolved Cu levels were increased from 3 to 126 nM. This resulted in an increased Cu adsorption capacity of the cell walls, probably due to an increase of surface area and roughness. Sexual reproduction (auxospore formation) was accelerated but was considered as a non-specific stress response. Cu-induced oxidative stress was indicated by a decrease of reduced glutathione (GSH), and a removal of superoxide anions monitored as an increasing activity of superoxide dismutase (SOD). Although Zn has no oxidative potential per se, cell division rates and chlorophyll c contents were lower in the culture with high Zn levels. In both cultures, the pro-oxidant Cu caused a decrease of chlorophyll a, decreasing photosynthetic O2 evolution and cell devision rates, and a growing number of deformed and broken cells.