Sialylation patterns of the mouse parotid secretory granules. Combined deacetylation, enzymatic degradation and lectin-gold binding.
We investigated the lectin cytochemistry of control and sialidase-digested sections of the mouse parotid gland by postembedding techniques. PNA and DBA lectins were used and their affinity sites were localized by employing conjugates with horseradish peroxidase that then reacted with anti-horseradish peroxidase antibody and protein A-gold. Potassium hydroxide pretreatment also was used before sialidase/PNA and DBA binding to investigate sialic acid acetylation. Ultrathin sections were obtained from specimens embedded in the acrylic hydrophilic resin, Bioacryl. The acini of mouse parotid gland contained polymorphous secretory granules differentially stained by the two lectins; the use of sialidase digestion and KOH deacetylation revealed that the sialic acids linked to beta-galactose are restricted to the electron-dense concentric areas of target granules, whereas the sialic acids linked to alpha-N-acetylgalactosamine contain C4-acetylated groups and are preferentially located in the electron-lucent regions of bizonal granules.
Menghi
G
G
Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy.
Marchetti
L
L
Bondi
A M
AM
Materazzi
G
G
D000107:Acetylation; D000818:Animals; D003594:Cytoplasmic Granules / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism; D007150:Immunohistochemistry; D037102:Lectins; D008297:Male; D051379:Mice; D016253:Microscopy, Immunoelectron; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D010306:Parotid Gland / Q000378:metabolism* / Q000648:ultrastructure; D012471:Salivary Proteins and Peptides / Q000378:metabolism*
D004798:Enzymes; D037102:Lectins; D012471:Salivary Proteins and Peptides; D019158:N-Acetylneuraminic Acid