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The emergence of antibiotic resistance genes (ARGs) in microbes can be largely attributed to the abuse and misuse of antibiotics and biocides. Quaternary ammonium compounds (QACs) have been used worldwide as common disinfectants and detergents; however, their potential impact on the spread and diffusion of ARGs is still unknown. In this study, we detected the QAC resistance gene (qacEΔ1), the 1 integron gene (intI1), and 12 ARGs (sul1, sul2, cfr, cml, fexA, tetA, tetG, tetQ, tetX, ermB, blaTEM, and dfrA1) in 48 water samples from three watersheds by quantitative PCR (qPCR). We investigated the evolution of bacterial antibiotic resistance under QAC and antibiotic environmental pressures by long-term continuous culture. In addition, five QACs were selected to investigate the effect of QAC on the efficiency of conjugation transfer. The changes in bacterial cell membrane and production of reactive oxygen species (ROS) were detected by flow cytometry, revealing the mechanism by which QAC affects the spread of antibiotic resistance. Our results showed that the QAC resistance gene was ubiquitous in watersheds and it had significant correlation with intI1 and seven ARGs (r = 0.999, p < 0.01). QACs could increase the resistance of bacteria to multiple antibiotics. Furthermore, all five QACs promoted the conjugation transfer of the RP4 plasmid; the optimal concentration of QACs was about 10−1–10−2 mg/L and their transfer efficiencies were between 1.33 × 10−6 and 8.87 × 10−5. QACs enhanced membrane permeability of bacterial cells and stimulated bacteria to produce ROS, which potentially promoted the transfer of plasmids between bacteria. In conclusion, this study demonstrated that QACs may facilitate the evolution and gene transfer of antibiotic resistance gene among microbiome. [ABSTRACT FROM AUTHOR]

Two new 1D Chain benzyltin complexes {[CH(O)C=N-N=C(Me)COO](CHOH)(CHCH)Sn} ( 1), {[CH(O)C-NH-N=C(Me)COO](CHCH)Sn} ( 2) were synthesized by the reactions of 2-oxo-propionic acid benzoyl hydrazone with dibenzyltin dichloride or tribenzyltin chloride, respectively. The two complexes were characterized by FT-IR, H, C and Sn NMR spectra, elemental analysis, X-ray single crystal diffraction and TGA. In vitro antitumor activities of both complexes were evaluated by the 3-(4,5-dimethylthiazoly-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against three human cancer cell lines (NCI-H460, HepG2, MCF7) and human cell line (HL7702). The 1 exhibited strong antitumor activity than 2, then it was expected after further chemical optimization of candidate compounds as anti-cancer drugs. The interaction between complexes and calf thymus DNA were studied by EB fluorescent probe, the interaction of 1 and 2 with calf thymus DNA were intercalation and electrostatic attraction. [ABSTRACT FROM AUTHOR]

This paper presents an electrochemical study on the separation of lanthanum from samarium on aluminum electrode at 773 K. The results from different electrochemical methods showed that Sm(III) and La(III) formed Al-Sm and Al-La intermetallic compounds on an aluminum electrode at electrode potential around −1.67 and −1.46 V, respectively. The electrochemical separation of lanthanum was carried out in LiCl-KCl-LaCl-SmCl melts on solid aluminum electrodes at 773 K by potentiostatic electrolysis at −1.45 V for 40 h and the separation efficiency was 99.1 %. [ABSTRACT FROM AUTHOR]

Anhydrous ytterbium chloride was obtained via solid-phase reaction from YbO with AlCl as a chlorination agent. The electrochemical behavior of the chloridized YbO was investigated on W electrodes in LiCl-KCl and LiCl-KCl-AlCl melts by cyclic voltammetry and square wave voltammetry. The results showed that the reduction/reoxidation of Yb(III)/Yb(II) was reversible and controlled by diffusion. The signals related to the formation of two Al-Yb intermetallic compounds were detected in LiCl-KCl-AlCl melt. Potentiostatic electrolysis was carried out in LiCl-KCl-AlCl-YbCl melt on W electrodes at 943 K at different potentials and AlYb, AlYb, AlLi and AlLi phases were detected in deposits. Then, the extraction of ytterbium was performed. The currents evolution was recorded by square wave voltammetry and the extraction efficiency was evaluated via inductive coupled plasma atomic emission spectrometer analysis during electrolysis. The initial extraction rate is much higher than that at longer times. The extraction efficiency was about 98.0 % for Yb(III) after potentiostatic electrolysis for 60 h at −1.84 V in LiCl-KCl-AlCl-YbCl melt. [ABSTRACT FROM AUTHOR]