Environmental factors relating to arsenic accumulation by <i>Dunaliella</i> sp

Yamaoka, Yukiho; Takimura, Osamu; Fuse, Hiroyuki

doi:10.1002/aoc.590020413

Cited by 16 publications

(3 citation statements)

References 19 publications

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“…Unfortunately, rigorous continuous culture experiments, such as those of Droop (1974) and Rhee (1974), have not been performed with As(V), but data from batch experiments are available to support our contention. For example, P and As cell quotas from the experiments of Hasegawa et al (2001) and Yamaoka et al (1988) are presented in Fig. 6 and show that As cell quotas follow the same pattern as P cell quotas affected by luxury uptake during log growth (Fig.…”

Section: Extension To Arsenicmentioning

confidence: 83%

“…6a,b). No As speciation was performed by Yamaoka et al (1988); hence, As* cannot be computed for Fig. 6c.…”

Section: Extension To Arsenicmentioning

confidence: 99%

“…(c) Data for Dunaliella sp. from Yamaoka et al (1988). Initial medium concentrations (mol L Ϫ1 ): (a) PO 4 ϭ 19, As(V) ϭ 12; (b) PO 4 ϭ 11, As(V) ϭ 0.010; and (c) PO 4 ϭ 33, As(V) ϭ 5.4.…”

Section: Extension To Arsenicmentioning

confidence: 99%

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Greedy algae reduce arsenate

Hellweger

Farley

Lall

et al. 2003

Limnology & Oceanography

112

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Algae reduce and methylate arsenate, producing arsenite (As(III)) when the growth rates are high and dimethylarsinic acid (DMA) when the growth rates are low. In lakes, this leads to high As(III) concentrations in the early stages of spring and fall blooms and high DMA concentrations in the summer. We hypothesize that under phosphorus (P)‐limited conditions, which usually exist in the summer, algae take up phosphate (PO4) and, because of similar chemical characteristics, As(V) as well. Inside the cell, As(V) is reduced to As(III), methylated to monomethylarsonic acid (MMA) and DMA, and then excreted. However, under non—P‐limited conditions, which exist in the early stages of blooms, algae up‐regulate their PO4 transport system to take up excess P, a phenomenon known as luxury uptake. Since As(V) is taken up by the PO4 transport system, As(V) uptake also increases at this time. Within the cell, the reduction of As(V) to As(III) is fast, but methylation is slower, causing As(III) to build up in the cell and be excreted, which, in turn, causes an increase in extracellular As(III). This mechanism permits the synergistic (luxury uptake) and antagonistic (competition) effects of PO4 on As(V) uptake and can therefore explain the seemingly contradictory results found in the literature. A mathematical model is constructed on the basis of existing established algal—nutrient interaction models and is used to simulate As transformation in two laboratory batch experiments. In addition to algal and P responses, the model can reasonably well reproduce the observed As(III) peak during the log growth phase and the more gradual appearance of DMA during the stationary phase.

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Section: Extension To Arsenicmentioning

confidence: 83%

“…6a,b). No As speciation was performed by Yamaoka et al (1988); hence, As* cannot be computed for Fig. 6c.…”

Section: Extension To Arsenicmentioning

confidence: 99%

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Greedy algae reduce arsenate

Hellweger

Farley

Lall

et al. 2003

Limnology & Oceanography

112

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Effect of glutathione on arsenic accumulation byDunaliella salina

Yamaoka¹,

Takimura²,

Fuse³

et al. 1999

Appl. Organometal. Chem.

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The behavior of marine algae (Dunaliella salina, Chattonella antiqua, Heteresigma akashiwo, Skeletonema costatum, chaetoceros debile and Thalassiosira weissflogii) against arsenate, arsenite and DMA in a medium and the effects of glutathione that influenced the redox condition on arsenic accumulation of D. salina were studied. It was found that the order of growth inhibition of marine algae by arsenic species was As(III) > As(V) > DMA. The order of arsenic accumulation by D. salina was As(V) ≥ As(III) > DMA at a concentration of 100 mgAsdm−3. A small part of the arsenic accumulated by D. salina was methylated in vivo. DMA was the major methylated arsenic compound. Methylated arsenic compounds were not present in the medium. Glutathione (GSH) treatment increased arsenic accumulation by D. salina at a concentration of 10–100 mgGSHdm−3. Buthionine sulfoxisamine (a potent and specific inhibitor of γ‐glutamylcysteine synthetase) strongly suppressed the effect of GSH on arsenic accumulation. These findings suggest that the intracellular glutathione concentration may be important for arsenic accumulation. Copyright © 1999 John Wiley & Sons, Ltd.

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Accumulation of arsenic and selenium by Dunaliella sp.

Yamaoka

Takimura

Fuse

et al. 1990

Applied Organom Chemis

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The unicellular marine alga, Dunaliella sp., was grown in seawater containing selenium and arsenic. Dunaliella sp. readily took up selenite from the medium over a broad range of concentrations (10-'0-10-5 mol dm-'). In comparison, uptake from selenate was generally minimal. Selenite was detectable in cells within 24 h and concentrations increased gradually with time. Also iron and zinc concentrations in Dunaliella sp. cells were largely affected by addition of arsenic and gallium. Arsenic concentrations in cultures were largely correlated to the accumulation of arsenic by Dunaliella sp., but did not affect the accumulation of selenium by Dunaliella sp. This implied that the accumulation process of selenium was different from that of arsenic.

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Environmental factors relating to arsenic accumulation by Dunaliella sp

Cited by 16 publications

References 19 publications

Greedy algae reduce arsenate

Greedy algae reduce arsenate

Effect of glutathione on arsenic accumulation byDunaliella salina

Accumulation of arsenic and selenium by Dunaliella sp.

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