raffinose and panose

The human gastrointestinal tract can be positively modulated by dietary supplementation of probiotic bacteria in combination with prebiotic carbohydrates. Here differential transcriptomics and functional genomics were used to identify genes in Lactobacillus acidophilus NCFM involved in the uptake and catabolism of 11 potential prebiotic compounds consisting of α- and β-linked galactosides and glucosides. These oligosaccharides induced genes encoding phosphoenolpyruvate-dependent sugar phosphotransferase systems (PTS), galactoside pentose hexuronide (GPH) permease, and ATP-binding cassette (ABC) transporters. PTS systems were upregulated primarily by di- and tri-saccharides such as cellobiose, isomaltose, isomaltulose, panose and gentiobiose, while ABC transporters were upregulated by raffinose, Polydextrose, and stachyose. A single GPH transporter was induced by lactitol and galactooligosaccharides (GOS). The various transporters were associated with a number of glycoside hydrolases from families 1, 2, 4, 13, 32, 36, 42, and 65, involved in the catabolism of various α- and β-linked glucosides and galactosides. Further subfamily specialization was also observed for different PTS-associated GH1 6-phospho-β-glucosidases implicated in the catabolism of gentiobiose and cellobiose. These findings highlight the broad oligosaccharide metabolic repertoire of L. acidophilus NCFM and establish a platform for selection and screening of both probiotic bacteria and prebiotic compounds that may positively influence the gastrointestinal microbiota.

Topics: ATP-Binding Cassette Transporters; Cellobiose; Gene Expression Regulation, Bacterial; Glucans; Isomaltose; Lactobacillus acidophilus; Oligosaccharides; Phosphoenolpyruvate Sugar Phosphotransferase System; Prebiotics; Raffinose; Sugar Alcohols

The range of substrates transported by the sugar-binding protein-dependent msm (multiple sugar metabolism) system of S. mutans was investigated. By determining the ability of unlabeled sugar to compete with radiolabeled melibiose transport, we have demonstrated that the transported sugars included a number of carbohydrates structurally related to raffinose. A model accommodating these results has been devised which accounts for the sugars transported by the msm transport system. Competition with radiolabeled melibiose transport indicated sucrose to be an msm substrate. This was confirmed by examination of uptake of radiolabeled sucrose in scrAB mutants lacking the sucrose-specific phosphotransferase system.

Topics: Biological Transport; Carbohydrate Metabolism; Carbon Radioisotopes; Fructose; Gene Expression Regulation, Bacterial; Glucans; Glucose; Isomaltose; Melibiose; Operon; Raffinose; Streptococcus mutans; Sucrose; Trehalose; Trisaccharides