Showing papers on "Melibiose published in 2013"

Aromatic thioglycoside inhibitors against the virulence factor LecA from Pseudomonas aeruginosa

Abstract: Three small families of hydrolytically stable thioaryl glycosides were prepared as inhibitors of the LecA (PA-IL) virulence factor corresponding to the carbohydrate binding lectin from the bacterial pathogen Pseudomonas aeruginosa. The monosaccharidic arylthio β-D-galactopyranosides served as a common template for the major series that was also substituted at the O-3 position. Arylthio disaccharides from lactose and from melibiose constituted the other two series members. In spite of the fact that the natural ligand for LecA is a glycolipid of the globotriaosylceramide having an α-D-galactopyranoside epitope, this study illustrated that the β-D-galactopyranoside configuration having a hydrophobic aglycon could override the requirement toward the anomeric configuration of the natural sugar. The enzyme linked lectin assay together with isothermal titration microcalorimetry established that naphthyl 1-thio-β-D-galactopyranoside (11) gave the best inhibition with an IC50 twenty-three times better than that of the reference methyl α-D-galactopyranoside. In addition it showed a KD of 6.3 μM which was ten times better than that of the reference compound. The X-ray crystal structure of LecA with 11 was also obtained.

Metabolism of Four α-Glycosidic Linkage-Containing Oligosaccharides by Bifidobacterium breve UCC2003

Abstract: Members of the genus Bifidobacterium are common inhabitants of the gastrointestinal tracts of humans and other mammals, where they ferment many diet-derived carbohydrates that cannot be digested by their hosts. To extend our understanding of bifidobacterial carbohydrate utilization, we investigated the molecular mechanisms by which 11 strains of Bifidobacterium breve metabolize four distinct α-glucose- and/or α-galactose-containing oligosaccharides, namely, raffinose, stachyose, melibiose, and melezitose. Here we demonstrate that all B. breve strains examined possess the ability to utilize raffinose, stachyose, and melibiose. However, the ability to metabolize melezitose was not common to all B. breve strains tested. Transcriptomic and functional genomic approaches identified a gene cluster dedicated to the metabolism of α-galactose-containing carbohydrates, while an adjacent gene cluster, dedicated to the metabolism of α-glucose-containing melezitose, was identified in strains that are able to use this carbohydrate.

Caldicoprobacter guelmensis sp. nov., a thermophilic, anaerobic, xylanolytic bacterium isolated from a hot spring.

Abstract: A hyperthermophilic anaerobic bacterium, designated D2C22T, was isolated from the hydrothermal hot spring of Guelma in north-east Algeria. The isolate was a Gram-stain-positive, non-sporulating, non-motile rod, appearing singly or in pairs (0.3–0.4×8.0–9.0 µm). Strain D2C22T grew anaerobically at 45–85 °C (optimum 65 °C), at pH 5–9 (optimum pH 6.8) and with 0–20 g NaCl l−1. Strain D2C22T used glucose, galactose, lactose, fructose, ribose, xylose, arabinose, maltose, cellobiose, mannose, melibiose, sucrose, xylan and pyruvate (only in the presence of yeast extract or biotrypticase) as electron donors. The end products from glucose fermentation were acetate, lactate, CO2 and H2. Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate and sulfite were not used as electron acceptors. The predominant cellular fatty acids were iso-C15 : 0 and iso-C17 : 0. The DNA G+C content was 41.6 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain D2C22T was most closely related to Caldicoprobacter oshimai JW/HY-331T, Caldicoprobacter algeriensis TH7C1T and Acetomicrobium faecale DSM 20678T (95.5, 95.5 and 95.3 % 16S rRNA gene sequence similarity, respectively). Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain D2C22T is proposed to be a representative of a novel species of the genus Caldicoprobacter within the order Clostridiales , for which the name Caldicoprobacter guelmensis sp. nov. is proposed. The type strain is D2C22T ( = DSM 24605T = JCM 17646T).

Thermoanaerobacter pentosaceus sp. nov., an anaerobic, extremely thermophilic, high ethanol-yielding bacterium isolated from household waste.

Abstract: An extremely thermophilic, xylanolytic, spore-forming and strictly anaerobic bacterium, strain DTU01T, was isolated from a continuously stirred tank reactor fed with xylose and household waste. Cells stained Gram-negative and were rod-shaped (0.5–2 µm in length). Spores were terminal with a diameter of approximately 0.5 µm. Optimal growth occurred at 70 °C and pH 7, with a maximum growth rate of 0.1 h−1. DNA G+C content was 34.2 mol%. Strain DTU01T could ferment arabinose, cellobiose, fructose, galactose, glucose, lactose, mannitol, mannose, melibiose, pectin, starch, sucrose, xylan, yeast extract and xylose, but not cellulose, Avicel, inositol, inulin, glycerol, rhamnose, acetate, lactate, ethanol, butanol or peptone. Ethanol was the major fermentation product and a maximum yield of 1.39 mol ethanol per mol xylose was achieved when sulfite was added to the cultivation medium. Thiosulfate, but not sulfate, nitrate or nitrite, could be used as electron acceptor. On the basis of 16S rRNA gene sequence similarity, strain DTU01T was shown to be closely related to Thermoanaerobacter mathranii A3T, Thermoanaerobacter italicus Ab9T and Thermoanaerobacter thermocopriae JT3-3T, with 98–99 % similarity. Despite this, the physiological and phylogenetic differences (DNA G+C content, substrate utilization, electron acceptors, phylogenetic distance and isolation site) allow for the proposal of strain DTU01T as a representative of a novel species within the genus Thermoanaerobacter , for which the name Thermoanaerobacter pentosaceus sp. nov. is proposed, with the type strain DTU01T ( = DSM 25963T = KCTC 4529T = VKM B-2752T = CECT 8142T).

Structural characterization of enzymatically synthesized dextran and oligosaccharides from Leuconostoc mesenteroides NRRL B-1426 dextransucrase.

Abstract: Leuconostoc mesenteroides NRRL B-1426 dextransucrase synthesized a high molecular mass dextran (>2 × 10(6) Da) with ~85.5% α-(1→6) linear and ~14.5% α-(1→3) branched linkages. This high molecular mass dextran containing branched α-(1→3) linkages can be readily hydrolyzed for the production of enzyme-resistant isomalto-oligosaccharides. The acceptor specificity of dextransucrase for the transglycosylation reaction was studied using sixteen different acceptors. Among the sixteen acceptors used, isomaltose was found to be the best, having 89% efficiency followed by gentiobiose (64%), glucose (30%), cellobiose (25%), lactose (22.5%), melibiose (17%), and trehalose (2.3%) with reference to maltose, a known best acceptor. The β-linked disaccharide, gentiobiose, showed significant efficiency for oligosaccharide production that can be used as a potential prebiotic.

The impact of glycerol and some carbohydrates on antibiotic production by Streptomyces hygroscopicus CH-7

Abstract: The impact of different carbon sources on the antibiotic production by Streptomyces hygroscopicus CH-7 was studied with the main goal to increase the yield of antibiotics hexaene H-85 and elaiophylin. Glucose, as a basic carbon source in the nutrition medium, was replaced with glycerol, xylose, sorbose, melibiose, inulin, and mannitol (15 g/dm3). Insuring the maximum yields of hexaene and elaiophylin of 192 and 88 μg/cm3, respectively, glycerol was shown to be the best carbon source among the investigated ones.

Celerinatantimonas yamalensis sp. nov., a cold-adapted diazotrophic bacterium from a cold permafrost brine.

Abstract: A facultatively anaerobic nitrogen-fixing bacterium, strain C7T, was isolated from a permafrost cryopeg on the Yamal Peninsula, Russia. Comparative analysis of 16S rRNA gene sequences revealed that this bacterium was closely related to Celerinatantimonas diazotrophica S-G2-2T with a similarity of 95.5 %. Strain C7T differed from Celerinatantimonas diazotrophica in its ability to hydrolyse gelatin and inability to use d-mannose, melibiose, l-rhamnose, myo-inositol, lactose, lactulose, d-mannitol, trehalose, dl-lactate, glycogen or l-proline as sole carbon sources. In addition, strain C7T grew over a temperature range of 0–34 °C with optimum growth at 18–22 °C. The whole-cell fatty acid profile included C16 : 0, C16 : 1ω7, C18 : 1ω7, C17 cyclo and summed feature 2 [comprising C12 : 0 aldehyde and/or unknown fatty acid 10.913 (MIDI designation) and/or iso-C16 : 1/C14 : 0 3-OH]. The DNA G+C content was 44.7 mol%. Strain C7T is thus considered to represent a novel species, for which the name Celerinatantimonas yamalensis sp. nov. is proposed. The type strain is C7T ( = VKM B-2511T = DSM 21888T).

Method for producing fructosylvalyl histidine oxidase preparation

Abstract: PROBLEM TO BE SOLVED: To provide an FVHO preparation having high stability and a dried FVHO preparation having low hygroscopicity.SOLUTION: The method for producing an FVHO preparation includes a step of allowing at least one component selected from phosphoric acid, casein peptone, D-glucosamine hydrochloride, melibiose, sorbose, lactose, fructose, melezitose, glucono-1,5-lactone, ribitol and sorbose to coexist in the preparation. A method for producing a dried FVHO preparation includes a step of allowing bicine to coexist in the preparation.

Method for producing fructosyl valyl histidine oxidase preparation

Abstract: Object An object of the present invention is to provide a highly stable FVHO preparation and a low-hygroscopicity dried FVHO preparation. Means for achieving the object A method for producing a FVHO preparation comprising a step of allowing at least one member selected from phosphoric acid, casein peptone, D-glucosamine hydrochloride, melibiose, sorbose, lactose, fructose, melezitose, glucono-1,5-lactone, and ribitol; and a method for producing a dried FVHO preparation, comprising a step of allowing Bicine to coexist.