The mechanisms of detoxification of As(III), dimethylarsinic acid (DMA) and As(V) in the microalga Chlorella vulgaris
Article
Pantoja Munoz, L., Purchase, D., Jones, H., Raab, A., Urgast, D., Feldmann, J. and Garelick, H. 2016. The mechanisms of detoxification of As(III), dimethylarsinic acid (DMA) and As(V) in the microalga Chlorella vulgaris. Aquatic Toxicology. 175, pp. 56-72. https://doi.org/10.1016/j.aquatox.2016.02.020
Type | Article |
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Title | The mechanisms of detoxification of As(III), dimethylarsinic acid (DMA) and As(V) in the microalga Chlorella vulgaris |
Authors | Pantoja Munoz, L., Purchase, D., Jones, H., Raab, A., Urgast, D., Feldmann, J. and Garelick, H. |
Abstract | The response of Chlorella vulgaris when challenged by As(III), As(V) and dimethylarsinic acid (DMA) was assessed through experiments on adsorption, efflux and speciation of arsenic (reduction, oxidation, methylation and chelation with glutathione/phytochelatin [GSH/PC]). Our study indicates that at high concentrations of phosphate (1.62 mM of HPO42−), upon exposure to As(V), cells are able to shift towards methylation of As(V) rather than PC formation. Treatment with As(V) caused a moderate decrease in intracellular pH and a strong increase in the concentration of free thiols (GSH). Passive surface adsorption was found to be negligible for living cells exposed to DMA and As(V). However, adsorption of As(III) was observed to be an active process in C. vulgaris, because it did not show saturation at any of the exposure periods. Chelation of As(III) with GS/PC and to a lesser extent hGS/hPC is a major detoxification mechanism employed by C. vulgaris cells when exposed to As(III). The increase of bound As-GS/PC complexes was found to be strongly related to an increase in concentration of As(III) in media. C. vulgaris cells did not produce any As-GS/PC complex when exposed to As(V). This may indicate that a reduction step is needed for As(V) complexation with GSH/PC. C. vulgaris cells formed DMASV-GS upon exposure to DMA independent of the exposure period. As(III) triggers the formation of arsenic complexes with PC and homophytochelatins (hPC) and their compartmentalisation to vacuoles. A conceptual model was devised to explain the mechanisms involving ABCC1/2 transport. The potential of C. vulgaris to bio-remediate arsenic from water appeared to be highly selective and effective without the potential hazard of reducing As(V) to As(III), which is more toxic to humans. |
Keywords | ABC/MRP; Arsenic; Chlorella vulgaris; Flow cytometry; ICP–MS; Oxidative stress; Intracellular pH; Efflux |
Research Group | Urban Pollution Research Centre (UPRC) |
Publisher | Elsevier |
Journal | Aquatic Toxicology |
ISSN | 0166-445X |
Electronic | 1879-1514 |
Publication dates | |
Online | 03 Mar 2016 |
01 Jun 2016 | |
Publication process dates | |
Deposited | 01 Apr 2016 |
Accepted | 26 Feb 2016 |
Submitted | 07 Jan 2016 |
Output status | Published |
Accepted author manuscript | License |
Copyright Statement | © 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.aquatox.2016.02.020 |
Scopus EID | 2-s2.0-84960874389 |
Web of Science identifier | WOS:000376797700007 |
Language | English |
https://repository.mdx.ac.uk/item/862y4
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