Analysis of bioavailable arsenic in rice with whole cell living bioreporter bacteria.

Détails

ID Serval
serval:BIB_B1F89D158CEE
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Analysis of bioavailable arsenic in rice with whole cell living bioreporter bacteria.
Périodique
Journal of Agricultural and Food Chemistry
Auteur⸱e⸱s
Baumann B., van der Meer J.R.
ISSN
0021-8561[print], 0021-8561[linking]
Statut éditorial
Publié
Date de publication
2007
Volume
55
Numéro
6
Pages
2115-2120
Langue
anglais
Résumé
A multiwell plate bioassay was developed using genetically modified bacteria (bioreporter cells) to detect inorganic arsenic extracted from rice. The bacterial cells expressed luciferase upon exposure to arsenite, the activity of which was detected by measurement of cellular bioluminescence. The bioreporter cells detected arsenic in all rice varieties tested, with averages of 0.02-0.15 microg of arsenite equivalent per gram of dry weight and a method detection limit of 6 ng of arsenite per gram of dry rice. This amounted to between approximately 20 and 90% of the total As content reported by chemical methods for the same sample and suggested that a major proportion of arsenic in rice is in the inorganic form. Calibrations of the bioassay with pure inorganic and organic arsenic forms showed that the bacterial cells react to arsenite with highest affinity, followed by arsenate (with 25% response relative to an equivalent arsenite concentration) and trimethylarsine oxide (at 10% relative response). A method for biocompatible arsenic extraction was elaborated, which most optimally consisted of (i) grinding rice to powder, (ii) mixing with an aqueous solution containing pancreatic enzymes, (iii) mechanical shearing, (iv) extraction in mild acid conditions and moderate heat, and (v) centrifugation and pH neutralization. Detection of mainly inorganic arsenic by the bacterial cells may have important advantages for toxicity assessment of rice consumption and would form a good complement to total chemical arsenic determination.
Mots-clé
Arsenic/analysis, Biological Assay/methods, Biological Availability, Escherichia coli/genetics, Genetic Engineering, Luciferases/genetics, Luminescence, Oryza sativa/chemistry, Seeds/chemistry
Pubmed
Web of science
Création de la notice
21/01/2008 13:36
Dernière modification de la notice
20/08/2019 15:20
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