Browsing by Subject "Sialidase"

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    Sex-related expression of sialic acid acceptor sugars in the mouse submandibular gland. Simultaneous visualization by confocal laser scanning microscopy
    (Murcia : F. Hernández, 1999) Menghi, Giovanna; Bondi, A.M.; Marchetti, L.; Sabbieti, M.G.; Gabrielli, M.G.; Materazzi, G.
    The novel combination of sialidase digestion with simultaneous PNA and DBA binding yielded marked differences on sialoglycoconjugate occurrence and distribution in the mouse submandibular gland acinar cells of the two sexes. Striking differences in the structure of terminal disaccharides within stored secretory sialoglycoconjugates were also found. High content of sialic acid, characterized by the terminal sequence sialic acid-a-N-acetylgalactosamine, was established to only occur in the male acini where secretory cells appeared to be differently stained; indeed, some cells exhibited codistribution of sialic acid-a-Nacetylgalactosamine and sialic acid-B-galactose terminal disaccharides, whereas other ones exclusively contained one of the two kinds of terminal sequences. In the female acinar cells, the secretory products were found to be almost exclusively composed by glycoconjugates having sialic acid subtended to B-galactose without appreciable differences between acinar cells. Our finding of such extensive differences in the acinar cells of male and female mice adds new insights into the submandibular gland sexual dimorphism, commonly attributed to the androgen responsiveness of the granular convoluted tubule portion of the gland.
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    Sialoglycoconjugate dimorphism of the mouse submandibular gland acinar cells. Ultrastructural evidence by lectin-protein A-gold probes and sialidase digestion
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Menghi, G.; Bondi., A. M.; Marchetti, L.; Gabrielli, M. G.; Materazzi, G.
    An ultrastructural analysis of lectin receptors on th e submandibular glands fro m mice of both sexes was performed utilizing horseradish pero xidase-labell ed lectins in conjunction with antiperox idase antibody and protein A-gold . Both qu alitati ve and quantit ati ve sexrelated differe nces in terminal suga r expression within secre tory gran ul es were detected. Following sia lidase digestion. also suhtenninal acceptor suga rs for terminal siali c ac ids, proved to be differentiall y ex pressed in the submandibular g land s of mal es and fema le s. Heteroge neo us distributi on of sialoglycoconjugates characteri zed bv the terminal disaccharide sialic acid-/3- galactose was f~ llIndt o occur in female ac inar ce lls. Also DBA reacti ve sites indicating the presence of terminal CI.-N-ace tylgalactosamin e discriminated betwee n male and female ac in ar sec re tor y glycoco nju ga tes. This difference was emphasized by sialidase pretreatment that ev idenced a marked occurrence of sialic acid subtended to u- N-ace tvlga lac tosamine in males in contrast to a modest pr es-e ~ce in fe males. The different sial ylation pa tt e rn s of acinar cell sec reto ry prod uc ts, pro bab ly related to a different exp ressio n of 0- and N-linked sia logl ycoconjugates, g iv e in sig ht into th e sex ual dimorphism of the mouse submandibular gland known until rece ntl y for the convoluted granular tubules.
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    Variety of sialic acids occurring in the bovine sublingual gland
    (Murcia : F. Hernández, 1994) Accili, Daniela; Gabrielli, M.G.; Menghi, Giovanna
    Sialoglycoconjugates were investigated in the bovine sublingual gland by direct visualization of sialic acid with specific lectins (LPA, SNA) and by histochemical procedures combined with sialidase digestion and lectins. The most reactive histological sructures were found to be acini which contained glycoconjugates with terminal disaccharides consisting of sialic acid linked to galactose or N-acetylgalactosamine. Resistance to periodate oxidation was interpreted as demonstrating a relevant presence of C7, C8 and Cg acetylated sialic acids. KOH-Sialidase-DBA and KOHAlcian blue sequences allowed the identification of C4 acetylated sialic acids.