Antibacterial Mechanisms of Reduced Iron-Containing Smectite-Illite Clay Minerals.
Environ Sci Technol
; 55(22): 15256-15265, 2021 11 16.
Article
em En
| MEDLINE
| ID: mdl-34723508
ABSTRACT
Reduced nontronite has been demonstrated to be antibacterial through the production of hydroxyl radical (â¢OH) from the oxidation of structural Fe(II). Herein, we investigated the antibacterial activity of more common smectite-illite (S-I) clays toward Escherichia coli cells, including montmorillonite SWy-3, illite IMt-2, 50-50 S-I rectorite RAr-1, 30-70 S-I ISCz-1, and nontronite NAu-2. Under an oxic condition, reduced clays (with a prefix r before mineral names) produced reactive oxygen species (ROS), and the antibacterial activity followed the order of rRAr-1 > rSWy-3 ≥ rNAu-2 â« rIMt-2 ≥ rISCz-1. The strongest antibacterial activity of rRAr-1 was contributed by a combination of â¢OH and Fe(IV) generated from structural Fe(II)/adsorbed Fe2+ and soluble Fe2+, respectively. Higher levels of lipid and protein oxidation, intracellular ROS accumulation, and membrane disruption were consistent with this antibacterial mechanism of rRAr-1. The antibacterial activity of other S-I clays depended on layer expandability, which determined the reactivity of structural Fe(II) and the production of â¢OH, with the expandable smectite being the most antibacterial and nonexpandable illite the least. Our results provide new insights into the antibacterial mechanisms of clay minerals.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ferro
/
Minerais
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article