Dépôt numérique

Selenite transport and its inhibition in the unicellular green alga Chlamydomonas reinhardtii.

Morlon, Hélène; Fortin, Claude; Adam, Christelle; Garnier-Laplace, Jacqueline (2006). Selenite transport and its inhibition in the unicellular green alga Chlamydomonas reinhardtii. Environmental Toxicology and Chemistry , vol. 25 , nº 5. p. 1408. DOI: 10.1897/2512039.1.

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The influence of time, ambient concentration, and medium composition on selenite (Se(IV)) uptake by the unicellular green alga Chlamydomonas reinhardtii has been investigated. The aims of the performed experiments were to describe the kinetics of accumulation, to characterize transport capacities, to identify key nutrients influencing absorption, and to establish links between speciation and bioavailability. Our results suggested that the adsorbed fraction was negligibl compared to the absorbed one. Over the short time scale considered, the absorption was linear with time, with an estimated conductance of approximately 0.2 nmol/m²/h/nM. Uptake was proportional to ambient levels in a broad range of intermediat concentrations (from nM to μM). However, conductances were higher at low concentrations (<nM) and then decreased with increasing concentrations (>μM). These results suggested that a specific but rapidly saturated transport system was involved at low concentrations, coupled with a nonspecific one that was only saturated at high ambient concentrations (∼mM). The latter could involve transporters used by anionic macronutrients, which is supported by the fact that increasing sulfate and nitrate concentrations induced significant inhibition of Se(IV) uptake. Finally, Se(IV) speciation changes caused y varying pH did not significantly affect bioavailability.

Type de document: Article
Mots-clés libres: oyanions; selenium; phytoplankton; transport; inhibition
Centre: Centre Eau Terre Environnement
Date de dépôt: 08 janv. 2021 16:20
Dernière modification: 08 janv. 2021 16:20
URI: http://espace.inrs.ca/id/eprint/10939

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