5,571 research outputs found

    Evolution: Velvet worm biogeography

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    The present-day distribution of velvet worms corresponds neatly to the ancient supercontinent Gondwana ā€” except for a puzzling outpost in southeast Asia. Jaw-dropping new fossil material now establishes when and how peripatid onychophorans reached this isolated spot

    Quantifying the timescales of fluid-rock interaction on Mars using the nakhlite meteorites

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    Etch pits within olivine grains from the nakhlite meteorites reveal the magnitude and timescale of water-mediated alteration of the martian crust

    Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

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    A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identified; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent substrate for abundant EPS synthesis. The ability to produce glucans appears to be widespread in the genus Lactobacillus. The monosaccharide composition of EPS produced by Lactobacillus reuteri strain LB 121 varied with the growth conditions (solid compared to liquid medium) and the sugar substrates (sucrose or raffinose) supplied in the medium. Strain LB 121 produced both a glucan and a fructan on sucrose, but only a fructan on raffinose. This is the first report of fructan production by a Lactobacillus species. EPS production increased with increasing sucrose concentrations and involved extracellular sucrase-type enzymes.
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