RESUMEN
With the increasing reports of antibiotic resistance in this species, Pseudomonas aeruginosa is a common human pathogen with important implications for public health. Bacterial quorum sensing (QS) systems are potentially broad and versatile targets for developing new antimicrobial compounds. While previous reports have demonstrated that certain amide compounds can inhibit bacterial growth, there are few reports on the specific inhibitory effects of these compounds on bacterial quorum sensing systems. In this study, thirty-one amide derivatives were synthesized. The results of the biological activity assessment indicated that A9 and B6 could significantly inhibit the expression of lasB, rhlA, and pqsA, effectively reducing several virulence factors regulated by the QS systems of PAO1. Additionally, compound A9 attenuated the pathogenicity of PAO1 to Galleria mellonella larvae. Meanwhile, RT-qPCR, SPR, and molecular docking studies were conducted to explore the mechanism of these compounds, which suggests that compound A9 inhibited the QS systems by binding with LasR and PqsR, especially PqsR. In conclusion, amide derivatives A9 and B6 exhibit promising potential for further development as novel QS inhibitors in P. aeruginosa.
Asunto(s)
Amidas , Antibacterianos , Descubrimiento de Drogas , Simulación del Acoplamiento Molecular , Pseudomonas aeruginosa , Percepción de Quorum , Pseudomonas aeruginosa/efectos de los fármacos , Percepción de Quorum/efectos de los fármacos , Amidas/farmacología , Amidas/química , Amidas/síntesis química , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/síntesis química , Relación Estructura-Actividad , Estructura Molecular , Pruebas de Sensibilidad Microbiana , Relación Dosis-Respuesta a Droga , AnimalesRESUMEN
A novel fluorescent conjugated polymer (poly(2-amino-N-(2-((4-ethynylphenyl) ethynyl) phenyl)-5-guanidinopentanamide)-1,4-phenylethynylene-1,4-phenyleneethynylene, PPE-Arg) was synthesized in this paper. We found that PPE-Arg could be quenched by picric acid (PA). Photoinduced electron transfer (PET) mechanism can be used to describe the fluorescence quenching of PPE-Arg. It could be speculated that the photo-induced electrons may be transferred from PPE-Arg to nitroaromatic explosives. In this paper, the experiment conditions and detection performance of PPE-Arg were systematically studied. The experiment results demonstrate PPE-Arg as a sensor for PA has a good linear range from 5â¯×â¯10-7 to 6â¯×â¯10-5 molâ¯L-1 with the calculated limit of detection (LOD) to be 1.0â¯×â¯10-7 molâ¯L-1. Meanwhile, reaction time between PPE-Arg and PA is less than 1â¯min. This proposed sensor was applied to rapidly detect nitroaromatic explosives in environmental water samples and satisfactory results were obtained.
RESUMEN
A novel hollow fiber membranes-based dynamic liquid-liquid micro-extraction (HF-DLLME) coupled with HPLC-UV detection has been developed for the residue analysis of tetracyclines in milk samples without deproteinization and degreasing. The influences of experimental parameters were investigated and optimized. The method showed a good performance. The limits of detection (LOD) are in the range of 0.95-3.6µg/L. The recoveries in spiked samples range from 92.38 to 107.3%. The relative standard deviations (RSDs) are lower than 8.66%. The advantages of this method are simple operation, high efficiency, absence of sample carryover and low cost.