Lewis Acid–Base Interaction Triggering Electron Delocalization to Enhance the Photodegradation of Extracellular Antibiotic Resistance Genes Adsorbed on Clay Minerals

Abstract

The transformation of extracellular antibiotic resistance genes (eARGs) is largely influenced by their inevitable photodegradation in environments where they tend to be adsorbed by ubiquitous clay minerals instead of being in a free form. However, the photodegradation behaviors and mechanisms of the adsorbed eARGs may be quite different from those of the free form and still remain unclear. Herein, we found that kaolinite, a common 1:1-type clay, markedly enhanced eARG photodegradation and made eARGs undergo direct photodegradation under UVA. The decrease in the transformation efficiency of eARGs caused by photodegradation was also promoted. Spectroscopy methods combined with density functional theory calculations revealed that the Lewis acid–base interaction between P–O in eARGs and Al–OH on kaolinite delocalized electrons of eARGs, thus resulting in increased photon absorption ability of eARGs. This ultimately led to enhanced photodegradation of kaolinite-adsorbed eARGs. Additionally, divalent Ca2+ could reduce the Lewis acid–base interaction-mediated adsorption of eARGs by kaolinite, thereby weakening the enhanced photodegradation of eARGs caused by electron delocalization. In contrast, the 2:1-type clay montmorillonite without strong Lewis acid sites was unable to delocalize the electrons to enhance the photodegradation of eARGs. This work allowed us to better evaluate eARGs’ fate and risk in real aqueous environments.

Facet-Specific Photocatalytic Degradation of Extracellular Antibiotic Resistance Genes by Hematite Nanoparticles in Aquatic Environments

“…The horizontal gene transfer potential of extracellular ARGs after photodegradation was assessed. The transformation efficiency of initial extracellular ARGs was quantified as 3.47 × 10 –4 (Figure f), aligning with values reported in a prior study . After visible light irradiation, the transformation efficiency of extracellular ARGs remained largely unaltered in the absence of hematite nanoparticles.…”

“…The light intensity at the center of the quartz tubes was measured to be 80 mW/cm 2 using a photometer (CELNP2000, Aulight Inc., China). It closely approximates the natural conditions (100 mW/cm 2 ) of equatorial summer sunlight and is consistent with many other scientific studies in the field. − Hematite nanoplates or nanorods representing various facets were sonicated in filtered river water for 20 min to achieve adequate dispersion at a final concentration of 40 mg/L before the adsorption and photodegradation experiments. This concentration falls well within the environmental range observed for hematite in natural water bodies .…”

“…The transformation efficiency of initial extracellular ARGs was quantified as 3.47 × 10 −4 (Figure 2f), aligning with values reported in a prior study. 26 After visible light irradiation, the transformation efficiency of extracellular ARGs remained largely unaltered in the absence of hematite nanoparticles. Regarding the dark control in the presence of hematite, the transformation efficiencies of extracellular ARGs were reduced to 1.10 × 10 −6 and 2.19 × 10 −6 for nanoplate and nanorod, respectively.…”

Lewis Acidic Metal–Organic Framework Assisted Ambient Liquid Extraction Mass Spectrometry Imaging for Enhancing the Coverage of Poorly Ionizable Lipids in Brain Tissue

“…However, in Zr 6 OTf-BTB, the central atom Zr was coordinated by OTf groups with strong electronegativity, and the strong electron-attracted effect caused the electron density at the Zr site to largely decrease, thus enhancing Lewis acidity. Because of the Lewis acidic sites, the phosphate group with several hydroxyl groups would bind to those sites by forming a chelate ring with Zr in acid conditions, which have been widely reported for other Lewis acidic materials. − In addition, the OTf group increases the hydrophilicity of the material (Figure S2), improves its dispersibility in solvents, and thus increases the contact between the analytes and the material.…”

Single cobalt atoms anchored on Ti 3 C 2 T x with dual reaction sites for efficient adsorption–degradation of antibiotic resistance genes

“…Antibiotic resistance genes (ARGs) have been recognized as one of emerging contaminants due to their pivotal role in the formation of pathogenic superbacteria ( 1 , 2 ). Different from conventional pollutants, ARGs are DNA fragments encoding antibiotic-resistant proteins, which can migrate through diverse environmental media and amplify in host microbes ( 3 – 5 ). Some wastewater treatment plants have become the breeding grounds and point source of ARGs.…”