RESUMEN
Raoultella terrigena strain Ez-555-6, isolated from a root nodule of Medicago sativa harvested in the Chernobyl exclusion zone, produces a non-referenced high-molecular-mass exopolysaccharide (EPS). The structure of this EPS was determined using a combination approach including monosaccharide composition (GLC-FID, HPAEC-PAD), determination of glycosylation sites (GLC-EIMS) and 1D/2D NMR ((1)H, (13)C) and ESIMS (HR, MS/MS) studies of oligosaccharides obtained from mild acid hydrolysis. The EPS was found to be a charged pentasaccharide with a repeating unit composed of D-galactose, D-glucose, D-mannose and D-glucuronic acid (1:2:1:1). Lactic acid and O-acetyl substituents were localized on galactose and glucose residues, respectively, as presented in the following structure:
Asunto(s)
Accidente Nuclear de Chernóbil , Enterobacteriaceae/química , Éteres/química , Polisacáridos Bacterianos/química , Polisacáridos Bacterianos/aislamiento & purificación , Secuencia de Carbohidratos , Glicósidos/química , Hidrólisis , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Monosacáridos/química , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en TándemRESUMEN
Steroidal glycoalkaloids of many Solanum species have recognized biological activities, especially those containing the glycosyl moiety alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-D-glucopyranose (chacotriose) whose peracetate is here synthesized and characterized by complete 1H and 13C NMR assignment.
