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The influence of pH on algal cell membrane permeability and its implications for the uptake of lipophilic metal complexes.

Lavoie, Michel; Le Faucheur, Séverine; Boullemant, Amiel; Fortin, Claude; Campbell, Peter G. C. (2012). The influence of pH on algal cell membrane permeability and its implications for the uptake of lipophilic metal complexes. Journal of Phycology , vol. 48 , nº 2. p. 293-302. DOI: 10.1111/j.1529-8817.2012.01126.x.

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Résumé

La transcription des symboles et des caractères spéciaux utilisés dans la version originale de ce résumé n’a pas été possible en raison de limitations techniques. La version correcte de ce résumé peut être lue dans le document original.

Uptake of lipophilic metal complexes by freshwater algae has recently been shown to be pH dependent. Here we look at different physiological aspects that could influence the diffusion of the lipophilic Cd complex, Cd(diethyldithiocarbamate)20 (Cd(DDC)20), into algal cells at different exposure pH values. Changes in cell membrane permeability were assessed as a function of pH for three species of green algae [Chlamydomonas reinhardtiiP. A. Dang., Pseudokirchneriella subcapitata (Korshikov) Hindák, and Chlorella fusca var. vacuolata Shihira et R. W. Kraus] using two neutral, nonionic probes, fluorescein diacetate (FDA) and D‐sorbitol. In parallel experiments, we exposed algae to inorganic Cd or to Cd(DDC)20 and monitored Cd intracellular metal distribution, together with phytochelatin synthesis. For the three algal species acclimated at pH 5.5 (w/wo DDC 1 μM) and exposed at this pH, their permeability to FDA and D‐sorbitol was consistently lower than for algae growing at pH 7.0 and exposed at this pH (P < 0.001). The ratio of the FDA hydrolysis rate measured at pH 7.0 with respect to the rate measured at pH 5.5 (both in the presence of DDC) correlated with the ratio of the Cd(DDC)20 initial internalization rate constant obtained at pH 7.0 versus that obtained at pH 5.5 (three algae species, n = 9, r = 0.85, P = 0.004). Our results strongly suggest that acidification affects metal availability to algae not only by proton inhibition of facilitated metal uptake but also by affecting membrane permeability.

Type de document: Article
Informations complémentaires: Résumé avec symboles
Mots-clés libres: Cd; cell membrane; chlorophyte; diethyldithiocarbamate; lipophilic metal complexes; permeabilith; pH
Centre: Centre Eau Terre Environnement
Date de dépôt: 19 oct. 2018 14:59
Dernière modification: 19 oct. 2018 14:59
URI: http://espace.inrs.ca/id/eprint/7294

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