title: Free sialooligosaccharides found in the unfertilized eggs of a freshwater trout, Plecoglossus altivelis. A large storage pool of complex-type bi-, tri-, and tetraantennary sialooligosaccharides.
abstract: Unfertilized eggs of Plecoglossus altivelis (a kind of freshwater trout, "Ayu" in Japanese) were found to contain a relatively large pool of three sialooligosaccharides. These free oligosaccharides were accumulated in the cytoplasm up to concentrations of about 35 ng per egg, which correspond to about 107 micrograms/g. Their structures were determined by a combination of chemical (composition and methylation analysis and Smith degradation) and instrumental (fast atom bombardment-mass spectrometry, secondary ion mass spectrometry, and 400-MHz1H NMR) analyses. The structures established represent a typical type of bi-, tri-, and tetraantennary sialooligosaccharides all of which end with di-N-acetylchitobiose structure (-GlcNAc beta 1-4GlcNAc) and alpha -2,3-linked NeuAc at reducing and nonreducing termini, respectively. These data show that these free sialooligosaccharides, which were originally protein-linked components, must be released during oogenesis. Although a specific functional requirement for their release is not known, the occurrence of such free sialooligosaccharides in normal animal cells or tissues has not been previously reported.
authors.affiliation: Department of Biophysics and Biochemistry, University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishii
authors.forename: M
authors.initials: M
authors.lastname: Iwasaki
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: P T
authors.initials: PT
authors.lastname: Kenny
authors.forename: H
authors.initials: H
authors.lastname: Komura
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002852:Chromatography, Ion Exchange; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009844:Oligosaccharides / Q000032:analysis*; D009865:Oocytes / Q000032:analysis*; D012016:Reference Values; D012487:Salmonidae / Q000378:metabolism*; D013347:Subcellular Fractions / Q000032:analysis; D014337:Trout / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D009844:Oligosaccharides; C016735:sialooligosaccharides