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Objectives: Subinhibitory concentration of antibiotics in the environment is an important risk factor for the horizontal transmission of antibiotic resistance genes (ARGs). The signaling mechanism of resistance gene transmission remains unknown. The aim of this study was to investigate whether indole could be used as a molecular signal to help the spread of ARGs under the stress of subinhibitory concentrations of antibiotics. Methods: The effect of indole on conjugation frequency was investigated through a conjugation test, and its effect on the Type IV secretion system and pili gene expression of E. coli was observed. Meanwhile, we were investigating the trend of changes in indole regulatory factors ibpA, tnaA, and concentration pumps. Subsequently, we predicted the receptors that specifically bind to indole. Finally, our study focused on elucidating the regulatory mechanism of indole synthesis. Results: Conjugate frequency was significantly increased under 1/5MIC concentration cefotaxime stress. The transferred ARGs were blaCTX-M and foxA. The mobile plasmid was IncY or IncI2. Meanwhile, the concentration of endogenous indole was also significantly increased. And, surprisingly, inhibition of endogenous indole production resulted in a significant decrease in conjugate frequency. However, the conjugate frequency increased once again when the strains reacquired the exogenous indole. Furthermore, the fluctuation trends of indole‐regulated factor (ibpA, tnaA) mRNA and concentration pumps (acrEF, mtr) mRNA consistently with that of indole. Then, we found that the receptors of indole may be four targets of TCSs: CreC, PhoB, AtoC, and UhpA. More than that, when strains retrieved the exogenous indole again, the mRNA levels of T4SS (virB2, virB6, and virD4) and pppA (coding Pili precursor) genes significantly increased. This indicates that there is a close relationship between indole and conjugated channels, which are necessary for horizontal transfer of genetic material. And then, the trends of indole and tnaA mRNA were consistent with that of ibpA (one of SOS response). So, this result confirmed that indole was regulated by SOS response under subinhibitory concentrations of antibiotics. Conclusions: It is always known that subinhibitory concentrations of antibiotics stimulate an SOS response in E. coli, which helps in the horizontal spread of ARGs by modulating indole. [ABSTRACT FROM AUTHOR]

As a widely distributed plant in Northeast China, Carex meyeriana Kunth (CMK) is generally considered to have antibacterial properties; however, there is a lack of scientific evidence for this. Therefore, we investigated the chemical composition of CMK extract and its effect against C. albicans. A total of 105 compounds were identified in the alcohol extracts of CMK by UPLC-Q-TOF-MS. Most were flavonoids, with Luteolin being the most represented. Among them, 19 compounds are found in the C. albicans lysates. After treatment with CMK ethanol extract, a significant reduction in the number of C. albicans colonies was observed in a vaginal douche solution from day 5 (p < 0.05). Furthermore, the CMK extract can reduce the number of C. albicans spores. The levels of IL-4, IL-6, IL-10, IL-1β, and TNF-α in vaginal tissues all exhibited a significant decrease (p < 0.05) compared to those in the model group as determined by ELISA. The results of HE staining showed that CMK extract can eliminate vaginal mucosa inflammation. CMK adjusts the vaginal mucosa cells by targeting twenty-six different metabolites and five specific metabolic pathways in order to effectively eliminate inflammation. Simultaneously, the CMK regulates twenty-three types of metabolites and six metabolic pathways against C. albicans infection. So, CMK strongly inhibits the growth of C. albicans and significantly reduces vaginal inflammation, making it a promising candidate for treating C. albicans infection. [ABSTRACT FROM AUTHOR]

Garnet‐type Li6Ca(La0.97Yb0.02RE0.01)2Nb2O12 (RE = Ho, Er, Tm) new phosphors were successfully synthesized via solid reaction at 900°C for 5 hours, whose course of phase evolution, macroscopic/local crystal structure and up‐/down‐conversion (UC/DC) photoluminescence were clarified. Mechanistic study and materials characterization were attained via XRD, Rietveld refinement, DTA/TG, electron microscopy (FE‐SEM/TEM), and Raman/reflectance/fluorescence spectroscopies. The phosphors were shown to exhibit UC luminescence dominated by a ~ 553 nm green band (5F4/5S2 → 5I8 transition) for Ho3+, a ~ 568 nm green band (4S3/2 → 4I15/2 transition) for Er3+ and a ~ 806 nm near‐infrared band (3H4 → 3H6 transition) for Tm3+ under 978 nm laser excitation, with CIE chromaticity coordinates of around (0.31, 0.68), (0.38, 0.60) and (0.17, 0.24), respectively. Analysis of the pump‐power dependence of UC intensity indicated that all the emissions involve a two‐photon mechanism except for the ~ 486 nm blue emission of Tm3+ (1G4 → 3H6), which requires a three‐photon process. The DC luminescence of these phosphors is featured by dominant bands at ~ 553 nm for Ho3+ (green, 5F4/5S2 → 5I8 transition), ~568 nm for Er3+ (green, 4S3/2 → 4I15/2 transition) and ~ 464 nm for Tm3+ (blue, 1D2 → 3F4 transition). The UC and DC properties were also comparatively discussed. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C(20)H(44)NO(2) (+)·Br(-), the cation and anion are connected via an O-H⋯Br hydrogen bond, forming an ionic pair. The cation is disordered over two conformations related by a mirror plane, and the anion is situated on a mirror plane so that the asymmetric unit contains half of the ionic pair. The long alkyl chain in the cation adopts an all-trans conformation. The crystal packing exhibits weak inter-molecular C-H⋯O inter-actions.