The structures of polysaccharides and glycolipids of Aspergillus fumigatus grown in the presence of human serum.
A study was made of polysaccharides and glycosphingolipids isolated from Aspergillus fumigatus grown in media supplemented with human serum from healthy donors. Fractionation of Cetavlon-precipitated polysaccharides on Sephacryl S-400 gave rise to an excluded fraction (Fraction I) with molecular weight of > 400 kDa and an included peak (Fraction II) with an average molecular weight of 30-80 kDa. Fraction I comprises about 5% of total polysaccharide and was identified as a glycogen-like molecule. Its structure was deduced from methylation data, treatment with amyloglucosidase, a red-brown coloration produced with an iodine solution and by 1H and 13C-NMR spectroscopy. It was previously suggested that higher amounts of glycogen-like polysaccharide (20%) were present in A. fumigatus grown in serum-free medium. Fraction II was identified as a galactomannan and was the main polysaccharide of A. fumigatus grown in serum-free medium. Fraction II was identified as a galactomannan and was the main 13C-NMR spectroscopy combined with partial acetolysis and methylation analysis. The 13C-NMR spectrum of the galactomannan showed a much greater complexity in the beta-D-gal f and alpha-D-man p C-1 regions, than was evident for galactomannan from serum-free cultures previously described, reflecting differences in the glycosylation pattern, stimulated in serum-supplemented medium. No differences in A. fumigatus glycosphingolipid could be detected between serum-containing and serum-free growth conditions. Our results demonstrate that the change in polysaccharide structure is a more specific response to the altered growth conditions and not merely a symptom of more general changes.
Bahia
M C
MC
Departamento de Microbiologia Geral, Universidade Federal do Rio de Janeiro.
Vieira
R P
RP
Mulloy
B
B
Hartmann
R
R
Bergter
E B
EB
D001232:Aspergillus fumigatus / Q000737:chemistry* / Q000254:growth & development; D001769:Blood; D002240:Carbohydrate Sequence; D003470:Culture Media; D005690:Galactose / Q000031:analogs & derivatives; D005936:Glucans / Q000737:chemistry; D006003:Glycogen / Q000737:chemistry; D006028:Glycosphingolipids / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000737:chemistry; D008745:Methylation; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry*; D016339:Spectrometry, Mass, Fast Atom Bombardment
D003470:Culture Media; D005936:Glucans; D006028:Glycosphingolipids; D008351:Mannans; D011134:Polysaccharides; C012990:galactomannan; D006003:Glycogen; D005690:Galactose