Displaying posts published in

November 2010

[Effects of Coriolus versicolor polysaccharides on productivity and longevity in Drosophila melanogaster]

Coriolus versicolor polysaccharides (CVP), extracted from Coriolus versicolor (L) Fr, were composed of 67.53% beta-D-glucose, 12.49% D-mannose, 11.49% L-abequose, 8.21% D-galactose, and trace L-acofriose. On Oregon K stock of Drosophila melanogaster, 0.5%-5% of CVP increased the number of taking food. CVP 2%, 3%, and 5% increased the frequency of mating and 0.5%-3% increased the number of flies in first filial generation (F1). CVP (2% and 3% in mated test; 1% and 2% in unmated test) prolonged the mean lifespan, the maximal lifespan, and median lethal time (LT50) of female flies, but not male flies.[…]

Characterization and structural analysis of the laccase I gene from the newly isolated ligninolytic basidiomycete PM1 (CECT 2971).

We have isolated and characterized the cDNA and genomic DNA coding for a phenoloxidase, laccase I, previously purified from culture supernatant of the newly isolated ligninolytic basidiomycete PM1 (CECT 2971). A cDNA library from basidiomycete PM1 was constructed, and laccase-encoding cDNAs were identified by screening with antiserum raised against the purified enzyme. The lac1 gene coding for the laccase was identified in a partial genomic library by using the isolated cDNA as a probe. Nucleotide sequence determination of the full-length cDNA revealed an open reading frame of 1,551 bp encoding a polypeptide of 517 amino acid residues with a putative signal peptide of 21 amino acid residues. Ten small introns interrupted the genomic DNA. A single 1.8-kb transcript mRNA was detected by Northern (RNA) blot analysis, and its 5′ end maps to a position 51 bp upstream from the site of initiation of protein synthesis. Eukaryotic regulatory sequences, CAAT and TATA, were observed in the 5′ flanking region, which also contains sequences similar to those of copper-regulated proteins. Comparative analysis of the predicted amino acid sequence showed that basidiomycete PM1 laccase I had great similarity to the laccases from Coriolus versicolor, Coriolus hirsutus, and Phlebia radiata.[…]

Effects of 1,5-anhydro-D-fructose on selected glucose-metabolizing enzymes.

It was verified, by n.m.r. and fast-atom-bombardment-m.s. studies, that the C-2 position of 1,5-anhydro-D-fructose, which was prepared by the reaction of immobilized glucose 2-oxidase from Coriolus versicolor (with 1,5-anhydro-D-glucitol), is hydrated to the acetal form in water. The effects of 1,5-anhydro-D-fructose on several glucose-metabolizing enzymes were compared with those of 1,5-anhydro-D-glucitol. Glucose 1-oxidase from Aspergillus niger was inhibited by 1,5-anhydro-D-fructose (Ki 6.6 mM) more effectively than 1,5-anhydro-D-glucitol (Ki 82.5 mM). Yeast and rat brain hexokinases phosphorylated 1,5-anhydro-D-fructose (Km,yeast 2.3 mM: Km,rat 0.79 mM) and 1,5-anhydro-D-glucitol (Km,yeast 3.9 mM; Km,rat 0.83 mM). The phosphorylated forms of these compounds inhibited D-glucose phosphorylation by yeast hexokinase (Ki of phosphorylated 1,5-anhydro-D-fructose 0.11 mM; Ki of phosphorylated 1,5-anhydro-D-glucitol 0.38 mM) and rat brain hexokinase (Ki of phosphorylated 1,5-anhydro-D-fructose 0.07 mM; Ki of phosphorylated 1,5-anhydro-D-glucitol 0.04 mM). Glucokinase phosphorylated neither 1,5-anhydro-D-fructose nor 1,5-anhydro-D-glucitol, and the phosphorylation of D-glucose by glucokinase was inhibited by them. Mutarotase was slightly inhibited by 1,5-anhydro-D-fructose, as well as by 1,5-anhydro-D-glucitol.[…]