The structure of the glucuronoxylomannan produced by culinary-medicinal yellow brain mushroom(Tremella mesenterica Ritz.:Fr.,Heterobasidiomycetes)grown as one cell biomass in submerged culture

摘要

The yellow brain mushroom Tremella mesenterica possesses a wide spectrum of medicinal properties,including immu-nostimulating,protecting against radiation,antidiabetic,anti-inflammatory,hypocholesterolemic,hepatoprotective,and antiallergic effects.A unique feature of T.mesenterica is that most of the above mentioned medicinal properties depend on glucuronoxylomannan(GXM)contained in fruiting bodies or produced in pure culture conditions.We developed a new strain of T.mesenterica CBS 101939,which grows in submerged culture and offers superior yields of one-cell biomass rich in exocellular heteropolysac-charide GXM.The structure of the GXM was analyzed by NMR spectroscopy and chemical methods.The polysaccharide has a defined repeating unit structure,which is O-acetylated at several points:3/4-O-Ac-beta-GlcA-(1->4)-beta-Xyl-(1->3)->beta-Xyl-(1->2)6-O-Ac-p-Man-(1 -"4)-p-Glc A-(1 ->2)-,->-[->3)-alpha-Man-(l->3)-alpha-Man-(1->3)-alpha-Man-(l->]->6-O-Ac-alpha-Man-(1->2)-These results differ from previously published structure of Tremella extracellular polysaccharides,where mannan backbone was believed to be randomly glycosylated with xylan chains of different length.