epiglucan and malic-acid

The beech mushrooms have customarily been revered by oriental societies for their nutritional and health benefits. We explored the mass spectrometry (MS) based spatial metabolomic variations between parts (cap and stipe) of two beech mushroom strains (brown and white). The principal component analysis (PCA) revealed their distinct primary (cap and stipe: PC1, 25.5%; strains: PC2, 12.5%) and secondary (cap and stipe: PC1, 10.3%; strains: PC2, 7.6%) metabolite patterns. The caps were rich in amino acids, fatty acids, and N-acetylglucosamine with higher protein and nitrogen contents. The stipes had abundant β-glucans, malic acid, and fructose. The discriminant secondary metabolites, especially, hypsiziprenols were higher in caps from brown strains. A fatty acid derivative, azelaic acid, was abundant in white strains (cap>stipe). We established a positive correlation for the cytotoxic activities of hypsiziprenols against ACHN cells. These spatial inter-strain metabolomic distinctions are potentially helpful for mushroom selection and improvement.

Topics: Acetylglucosamine; Agaricales; Amino Acids; beta-Glucans; Fatty Acids; Fructose; Fruiting Bodies, Fungal; Malates; Mass Spectrometry; Metabolomics; Nitrogen; Principal Component Analysis; Proteins; Species Specificity

An acidic exopolysaccharide was isolated from a selected strain of Aureobasidium pullulans. On the basis of spectroscopic and chromatographic techniques, the polymer was identified as a beta-D-glucan containing a main chain of (1-->3)-linked beta-D-glucopy-ranosyl units substituted at the O-6 position by single beta-D-glucopyranosyl side chains. The ratio of units in the main chain to units in the side chain was found to be 1.4:1. The ionic character of this exopolysaccharide is due to the presence of malate residues which are linked to the polymer through ester bonds. The degree of substitution was estimated to be very low (0.05). In aqueous solution no signals are present in the NMR spectra strongly suggesting that the polymer adopts a rigid ordered conformation as further confirmed by rheological data. A solvent-induced conformational transition was observed in DMSO in which NMR spectra with good signal-to-noise ratio were obtained. The solution behaviour of the polymer is similar to that of other branched (1-->3)-beta-D-glucans in spite of both the degree of branching and the substitution with malate groups.

Topics: beta-Glucans; Carbohydrate Conformation; Carbohydrate Sequence; Glucans; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Malates; Mitosporic Fungi; Molecular Sequence Data; Rheology; Solutions; Spectroscopy, Fourier Transform Infrared; Viscosity