ABSTRACT
Microbial electrolysis cells (MECs) have been applied for antibiotic degradation but simultaneously induced antibiotic resistance genes (ARGs), thus representing a risk to disseminate antibiotic resistance. However, few studies were on the potential and risk of ARGs transmission in the MECs. This work assessed conjugative transfer of ARGs under three tested conditions (voltages, cell concentration, and donor/recipient ratio) in both single- and two-chamber MECs. The results indicated that voltages (> 0.9 V) facilitated the horizontal frequency of ARGs in the single-chamber MECs and anode chamber of two-chamber MECs. The donor cell number (donor/recipient ratio was 2:1) increased the transfer frequency of ARGs. Furthermore, voltages ranged from 0.9 to 2.5 V increased reactive oxygen species (ROS) production and cell membrane permeability in MECs. These findings offer new insights into the roles of ARG transfer under different applied voltages in the MECs, which should not be ignored for horizontal transfer of antibiotic resistance.
Subject(s)
Anti-Bacterial Agents , Genes, Bacterial , Anti-Bacterial Agents/pharmacology , Drug Resistance, Microbial/genetics , Electrolysis , Gene Transfer, HorizontalABSTRACT
The impact of pollutants from road runoff on receiving water bodies becomes increasingly serious. However, less is known about the study on the distribution of metal speciation in particles with different sizes, and the interaction among metal speciation. Our research is aimed at investigating speciation distribution of copper (Cu) and zinc (Zn) in particles and the interaction among metal speciation. Stainless steel sieves in different sizes were used to accomplish filtration scheme. Sequential extraction procedures contained five steps for the chemical fractionation of metals. Flame atomic absorption spectrometry (Shimadzu, AA-6800) was used to determine the concentration of metal speciation. Speciation distribution of Cu was similar to that of Zn. Size distribution implied that small particles (<75 µm) determined the distribution for both Cu and Zn, as well as their migration. Correlation analysis indicated that the interaction among speciation of Cu was different from that of Zn.
