Uptake and metabolism of arsenate, methylarsonate and arsenobetaine by axenic cultures of the phytoplankton Dunaliella tertiolecta
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Elliott Duncan
Abstract
Axenic cultures of the phytoplankton Dunaliella tertiolecta were dosed with either arsenate [As(V)], methylarsonate (MA) or arsenobetaine (AB) at environmentally realistic concentrations (2 μg l-1) to investigate incorporation and transformation of arsenic species. Total arsenic concentrations in cultures dosed with As(V) were significantly higher than those dosed with MA and AB (6–10 μg g-1 compared to 1–3 μg g-1). Arsenic concentrations in As(V)-dosed cultures increased over time, whereas arsenic concentrations in MA- and AB-dosed cultures remained constant, indicating that As(V) is rapidly and continuously incorporated into the cell in comparison to MA and AB. Arsenic was found predominantly in the residue fractions (29–55%) of all cultures, irrespective of culture age. This was attributed to the ability of inorganic arsenic as arsenite [As(III)] to bind to proteins and/or phytochelatins. 2-Dimethylarsinoylethanol (DMAE) was the main arsenic species found in lipid cell fractions. Within the water-soluble and residue cell fractions, arsenic was isolated primarily as As(V), although it is likely the extraction procedure may have converted some As(III) to As(V). Small amounts of As(III), MA, dimethylarsinate (DMA) and arsenoribosides were also found in the lipid and water soluble As fractions. All cultures showed an increase in DMA and arsenoriboside species over time. The significance of these results is that while AB, the major arsenical in marine animals, is not produced or accumulated by this phytoplankton species, the possible precursors to AB formation are produced.
©2010 by Walter de Gruyter Berlin New York
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- Seasonality of caulerpenyne content in native Caulerpa prolifera and invasive C. taxifolia and C. racemosa var. cylindracea in the western Mediterranean Sea
- Uptake and metabolism of arsenate, methylarsonate and arsenobetaine by axenic cultures of the phytoplankton Dunaliella tertiolecta
Articles in the same Issue
- Review
- Addendum to the synoptic review of red algal genera
- Research articles
- Two new species of Polysiphonia (Ceramiales, Florideophyceae) from the western Atlantic
- Apoglossum gregarium (Delesseriaceae, Rhodophyta) from Greece: a new record for the eastern Mediterranean Sea
- New macroalgal records for the Aegean Sea (Greece, eastern Mediterranean Sea)
- On the occurrence of Mesophyllum expansum (Philippi) Cabioch et Mendoza (Melobesioideae, Corallinales, Rhodophyta) in the Mediterranean Sea, the Canary Isles and the Azores
- Additional records of Gelidiella fanii (Gelidiales, Rhodophyta) from the western Pacific based on morphology, rbcL and cox1 analyses
- Nuclear rDNA sequences of Wittrockiella amphibia (Collins) comb. nov. (Cladophorales, Chlorophyta) and morphological characterization of the mat-like growth form
- Morphology of the flagellar pore complex in Prorocentrum minimum (Dinophyceae) from the Adriatic and Baltic Seas
- Seasonality of caulerpenyne content in native Caulerpa prolifera and invasive C. taxifolia and C. racemosa var. cylindracea in the western Mediterranean Sea
- Uptake and metabolism of arsenate, methylarsonate and arsenobetaine by axenic cultures of the phytoplankton Dunaliella tertiolecta
