RESUMEN
Shiga toxin (Stx)-producing, food-contaminating Escherichia coli (STEC) is a major health concern. Plant-derived pectin and pectic-oligosaccharides (POS) have been considered as prebiotics and for the protection of humans from Stx. Of five structurally different citrus pectic samples, POS1, POS2 and modified citrus pectin 1 (MCP1) were bifidogenic with similar fermentabilities in human faecal cultures and arabinose-rich POS2 had the greatest prebiotic potential. Pectic oligosaccharides also enhanced lactobacilli growth during mixed batch faecal fermentation. We demonstrated that all pectic substrates were anti-adhesive for E. coli O157:H7 binding to human HT29 cells. Lower molecular weight and deesterification enhanced the anti-adhesive activity. We showed that all pectic samples reduced Stx2 cytotoxicity in HT29 cells, as measured by the reduction of human rRNA depurination detected by our novel TaqMan-based RT-qPCR assay, with POS1 performing the best. POS1 competes with Stx2 binding to the Gb3 receptor based on ELISA results, underlining the POS anti-STEC properties.
Asunto(s)
Adhesión Bacteriana , Infecciones por Escherichia coli/microbiología , Escherichia coli O157/fisiología , Oligosacáridos/química , Pectinas/metabolismo , Prebióticos/análisis , Toxina Shiga/toxicidad , Escherichia coli O157/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Heces/microbiología , Células HT29 , Humanos , Oligosacáridos/metabolismo , Pectinas/química , Toxina Shiga/metabolismoRESUMEN
Cranberry juice has been recognized as a treatment for urinary tract infections on the basis of scientific reports of proanthocyanidin anti-adhesion activity against Escherichia coli as well as from folklore. Xyloglucan oligosaccharides were detected in cranberry juice and the residue remaining following commercial juice extraction that included pectinase maceration of the pulp. A novel xyloglucan was detected through tandem mass spectrometry analysis of an ion at m/z 1055 that was determined to be a branched, three hexose, four pentose oligosaccharide consistent with an arabino-xyloglucan structure. Two-dimensional nuclear magnetic resonance spectroscopy analysis provided through-bond correlations for the α-L-Araf (1â2) α-D-Xylp (1â6) ß-D-Glcp sequence, proving the S-type cranberry xyloglucan structure. Cranberry xyloglucan-rich fractions inhibited the adhesion of E. coli CFT073 and UTI89 strains to T24 human bladder epithelial cells and that of E. coli O157:H7 to HT29 human colonic epithelial cells. SSGG xyloglucan oligosaccharides represent a new cranberry bioactive component with E. coli anti-adhesion activity and high affinity for type 1 fimbriae.
Asunto(s)
Adhesión Bacteriana/efectos de los fármacos , Bebidas/análisis , Células Epiteliales/microbiología , Escherichia coli/efectos de los fármacos , Glucanos/farmacología , Extractos Vegetales/farmacología , Vaccinium macrocarpon/química , Xilanos/farmacología , Línea Celular , Escherichia coli/fisiología , Glucanos/química , Humanos , Extractos Vegetales/química , Xilanos/químicaRESUMEN
Bromodomains are key transcriptional regulators that are thought to be druggable epigenetic targets for cancer, inflammation, diabetes and cardiovascular therapeutics. Of particular importance is the first of two bromodomains in bromodomain containing 4 protein (BRD4(1)). Protein-ligand docking in BRD4(1) was used to purchase a small, focused screening set of compounds possessing a large variety of core structures. Within this set, a small number of weak hits each contained a dihydroquinoxalinone ring system. We purchased other analogs with this ring system and further validated the new hit series and obtained improvement in binding inhibition. Limited exploration by new analog synthesis showed that the binding inhibition in a FRET assay could be improved to the low µM level making this new core a potential hit-to-lead series. Additionally, the predicted geometries of the initial hit and an improved analog were confirmed by X-ray co-crystallography with BRD4(1).
Asunto(s)
Diseño de Fármacos , Ligandos , Proteínas Nucleares/antagonistas & inhibidores , Factores de Transcripción/antagonistas & inhibidores , Sitios de Unión , Proteínas de Ciclo Celular , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Humanos , Simulación del Acoplamiento Molecular , Proteínas Nucleares/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Quinoxalinas/química , Quinoxalinas/metabolismo , Relación Estructura-Actividad , Factores de Transcripción/metabolismoRESUMEN
A series of structurally novel, operationally convenient, and efficient chiral 2-phosphino-2,3-dihydrobenzo[d][1,3]oxaphosphole ligands was developed. Applications of ligands 3a and 3b in rhodium-catalyzed asymmetric hydrogenation of alpha-(acylamino)acrylates and beta-(acylamino)acrylates provided excellent enantioselectivities (up to >99% ee) and reactivities (up to 10,000 TON).