Heterogeneity of the genus Myrothecium as revealed by cell wall polysaccharides

The polysaccharides obtained from the alkali-extractable, water-soluble fra ction (F1SS) from the cell wall of Myrothecium verrucaria and Myrothecium a troviride were shown to be composed of beta-(1-->6)-galactofuranose fully s ubstituted at O-2 by terminal residues of alpha -glucopyranose and alpha -g lucuronic acid. Glucuronic acid was substituted at O-4 by glucopyranose in the Myrothecium species M. inundatum, M. setiramosum, M. prestonii, M. tong aense and M. roridum. The acidic polysaccharides from Phaeostilbella atra ( =Myrothecium atrum) and Myrothecium gramineum lacked the backbone of 2,6 di -b-substituted galactofuranose and contained a high amount of O-5-substitut ed beta -galactofuranose. The structures of the polysaccharides isolated fr om Myrothecium cinctum and Myrothecium penicilloides were unrelated to each other and to the polysaccharides from the other species analysed. The usef ulness of these polysaccharides as a characteristic for delimitation of the genus Myrothecium is discussed.