Galactomannans from the cell walls of species of Paecilomyces sect. Paecilomyces and their teleomorphs as immunotaxonomic markers

An alkali-extractable and water-soluble fraction (F1S) was obtained from ce ll walls of Paecilomyces variotii and species of the related genera Talarom yces, Byssochlamys and Thermoascus. The structure of the main polysaccharid e of these fractions was studied and found to consist of a core of (1 --> 6 )-alpha-mannopyranose partially substituted at O-2 by chains of galactofura nose and shorter chains of mannopyranose. The differences in the regularity of the branching points and the length of the galactofuranose side chains are useful to distinguish between species. These differences were detected by immunological methods, since highly specific polyclonal antibodies were raised against these polysaccharides. Mycelium of P. variotii CBS 990.73A w as stained by indirect immunofluorescence. The polysaccharides studied in t his work differ from the one described for species from section Isarioidea, and this is another indication of the heterogeneity of the genus Paecilomy ces.