Cadmium induced phytochelatins in marine algaPhaeodactylum tricornutum:effect of metal speciation

Abstract

The production of phytochelatins (PCs) in the marine diatom Phaeodactylum tricornutum in response to cadmium has been studied as a function of the exposure time, concentration and chemical speciation. The results agree with the role of PCs in the detoxification and homeostasis of Cd in this alga. The chemical speciation of the metal was found to influence the synthesis of PCs. The use of Cd ion buffer solutions shows that the induction of PCs is controlled by the free ion rather than by the total or chelated Cd in solution.

Production of Phytochelatins in the Marine Diatom Phaeodactylum tricornutum in Response to Copper and Cadmium Exposure

“…Similarly to the Cu-exposed cells, cultures of Phaeodactylum tricornutum exposed to cadmium excess showed the appearance of an inducible, UVabsorbing, Cd-and SH-containing chromatographic peak, with a SH:Cd molar ratio of 1.9 ± 0.4, as described in details in a previous paper (Morelli and Scarano 1995) thus indicating the presence of cadmium-phytochelatins complexes (Cd-PCs). Here, carrying out exposure tests with Cu or Cd additions, the response of the algal cells to excess Cu has been compared with that of Cd.…”

“…The PC production in response to Cu exposure was evaluated as a function of the intracellular metal concentration, and compared to that obtained in response to Cd, which has previously been shown to be a good inducer in this alga species (Kawaguchi and Maita 1990;Morelli and Scarano 1995).…”

PRODUCTION OF PHYTOCHELATINS AND GLUTATHIONE BY MARINE PHYTOPLANKTON IN RESPONSE TO METAL STRESS1

“…The diatoms Thalassiosira weissflogii and Phaeodactylum tricornutum showed a high PC production in metal exposure experiments (Rijstenbil and Wijnholds 1996, Ahner et al 2002). These species have been extensively used by many workers to assess the effects of a range of metals on PC production (Ahner et al 1995, Ahner and Morel 1995, Cid et al 1995, Morelli and Scarano 1995, 2001, Lee et al 1996, Rijstenbil and Wijnholds 1996, Torres et al 1997) because of their well‐known physiology and relative ease of culturing.…”

Effects of Metal Combinations on the Production of Phytochelatins and Glutathione by the Marine Diatom Phaeodactylum tricornutum

“…Phaeodactylum tricornutum is an efficient producer of phytochelatins, capable of readily synthesising a wide range of phytochelatins under metal stress (Rijstenbil & Wijnholds 1996). Several studies have been undertaken to characterise phytochelatins produced by P. tricornutum (Morelli & Scarano 1995;Rijstenbil & Wijnholds 1996;Morelli & Pratesi 1997;Torres et al 1997;Scarano & Morelli 2002). The effects of combinations of toxic metals on phytochelatin and glutathione production by P. tricornutum, however, have not yet been investigated.…”