Cell wall composition affects Cd super(2) super(+) accumulation and intracellular thiol peptides in marine red algae

• Published in: Aquatic toxicology 2007-02, Vol.81 (1), p.65-72
• Main Authors: Garcia-Rios, V, Freile-Pelegrin, Y, Robledo, D, Mendoza-Cozatl, D, Moreno-Sanchez, R, Gold-Bouchot, G
• Format: Article
• Language: English
• Subjects: Chondrophycus; Chondrophycus poiteaui; Gracilaria cornea; Marine
• ISSN: 0166-445X
• DOI: 10.1016/j.aquatox.2006.11.001

Two red macroalgae species, Gracilaria cornea and Chondrophycus poiteaui, were evaluated for their intra and extracellular Cd super(2) super(+) accumulation capacity, photosynthetic response and thiol peptide production. Algae were exposed for 3 and 7 days to 0.1 and 1 mu gCdCl sub(2)ml super(-) super(1) (0.89 and 8.9 mu M). Intracellular accumulation of Cd super(2) super(+) by G. cornea was relatively low, only comprising 20% of total metal (intracellular+extracellular). In contrast, C. poiteaui accumulated intracellularly close to 100% of total Cd super(2) super(+). In both species, metal uptake was dependent on the external Cd super(2) super(+) concentration, metal exposure time and cell wall composition. In response to Cd super(2) super(+) exposure, low amounts of thiol peptides were synthesized and the major difference between G. cornea and C. poiteaui was in the cell wall composition. The absence of insoluble polysaccharides in the cell wall of C. poiteaui suggested that this insoluble fraction might be involved in establishing an efficient barrier for the intracellular accumulation of Cd super(2) super(+). This is the first study in which the cell wall composition, its influence on Cd super(2) super(+) accumulation and intracellular responses in red macroalgae are evaluated.