73 research outputs found

    Bildung von präbiotischen Exopolysacchariden durch Lactobazillen

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    Exopoly- and heterooligosaccharides have diverse functions in foodstuffs, ranging from texturizers to prebiotic additives, that may influence the microflora of the human gut in a positive way. In 107 lactobacilli of intestinal or cereal origin 15 fructan forming lactobacilli could be identified, harboring fructansucrase genes. The fructansucrase from L. sanfrancicensis TMW 1.392 was cloned and overexpressed in E. coli and the resulting gene product was characterized. A mutant with a destroyed fructansucrase gene was constructed, showing that this gene is responsible for the formation of fructan as well as the sucrose metabolism and the formation of fructo- and heterooligosaccharides by L. sanfranciscensis TMW 1.392.Exopoly- und Heterooligosaccharide haben vielfältige Bedeutungen, die von der Strukturbildung in Lebensmitteln bis zu Präbiotika reichen, die unsere Intestinalflora positiv beeinflussen können. Innerhalb von 107 getreideassoziierten und intestinalen Lactobazillen konnten in 15 Fructanbildnern Gene für Fructansucrasen nachgewiesen werden. Die Fructansucrase des Sauerteigisolates Lactobacillus sanfranciscensis TMW 1.392 wurde kloniert, in E. coli überexprimiert und das gereinigte Enzym charakterisiert. Mit der Erzeugung einer Fructansucrase-negativen Mutante wurde nachgewiesen, dass das Enzym sowohl für Fructanbildung, als auch für die Bildung von Fructo- und Heterooligosacchariden und den Saccharosestoffwechsel von L. sanfranciscensis TMW 1.392 verantwortlich ist

    The crystal structure of diaquabis(2,4-dinitrophenolato) cobalt(II) tetrahydrate

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    The crystal and molecular structure of diaquabis(2,4-dinitrophenolato)cobalt(II) tetrahydrate, [Co(dnp)2 · (OH2)2] · 4 H2O, C12H18CoN4O16, has been determined at room temperature. The red-brown crystals are triclinic, space group P1̄ with unit cell dimensions a = 8.961(3) Å, b = 11.573(3) Å, c = 4.872(1) Å, α = 93.05(2)°, β = 90.72(2)°, γ = 90.16(2)°, Z = 1 and Dx = 1.755 Mg m-3. The structure was refined by a full-matrix least-squares procedure on F to final R = 0.037 using 1644 reflections with I ≥ 3.0σ(I). The cobalt(II) atom (which lies on a center of inversion) exists in a slightly distorted octahedral geometry with the basal plane being defined by two phenoxide (2.001(2) Å) and two nitro oxygen atoms (2.110(2) Å) and the axial positions by two oxygen donor atoms derived from two symmetry related H2O molecules (2.092(2) Å). The lattice is stabilised by a network of hydrogen-bonding contacts

    The crystal structure of pentaaquabis(2,4-dinitrophenolato) barium(II)

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    The crystal and molecular structure of [Ba(dnp)2(OH2)5], where dnp is 2,4-dinitrophenoxide, has been determined at room temperature. The coordination number of the barium atom is nine with two phenoxide atoms, one nitro oxygen atom and six water molecules providing a O9 donor set that defines a distorted capped square antiprismatic geometry. The presence of bridging water molecules leads to the formation of dinuclear barium entities that are further linked to each other via hydrogen bonds (involving the water molecules) which in turn results in the construction of two-dimensional networks. Successive layers are linked by the dnp molecules via weak Ba . . . O interactions (>3.2 Ã…) as well as hydrogen bonds. Evidence is found for both intra- and inter-molecular base stacking
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