This study describes the isolation of the mt('- )mating type substance (MTS) by means of zwitterionic detergents and ultrasonication. The component is an extremely high molecular weight glycoprotein of more than 3 million daltons and could be characteized in essential features of its functional structure. In contrast to the multivalent mt('-) isoagglutinin, from which it is isolated, the MTS is incapable of causing homotypic agglutination between mt('+) gametes. The "univalent" glycoprotein has been crosslinked with poly-L-lysine and carbodiimide to reestablish a multivalent principle capable of agglutinating mt('+) gametes. The synthesized principle possesses the same enzyme sensitivities as the mt('-) gametes, being inactivated by the (alpha)-exogalactosidase and (alpha)-exo-N-acetyl-galactosaminidase. The real ligand within the glycoprotein is therefore of carbohydrate nature with terminal galactose and N-acetylgalactosamine residues in (alpha)-linkage. Gamete contact thus depends decisively on carbohydrate binding. The insensitivity of the attainment of the mt('-) contact capacity to Tunicamycin and Bacitracin, the sensitivity of the established contact capacity to alkaline borohydride reduction and to (alpha)-D-N-acetylgalactosaminyl-oligosaccharidase and the insensitivity to Endoglycosidase H indicate that, within the MTS, the ligand involved in recognition and adhesion must be O-glycosidically linked to the polypeptide chain. / In spite of the essential role of these terminal sugars the mt('-) MTS could not be masked by lectins nor did the mt('-) gametes selectively adhere to lectin-coated agarose beads. When checked with both gamete types, the synthesized multivalent principle exhibits the same sex and species specificity as the mt('-) gametes. These data on the mt('-) MTS reveal a fundamental pattern of the gametic biopolarity and its biosynthesis, whereas the contact capacity in the complementary mt('+) sex is inherent in an N-linked carbohydrate structure and synthesized by the lipid-linked pathway, the mt('-) capacity seems to reside in an O-glycosidically linked ligand. A second gametic bipolarity appears to reside in the components involved in the initiation of gamete fusion. The pairing capacity of the mt('-) gametes is inhibited by the effects of Bacitracin, while the contact capacity with respect to the mating type reaction is not. / Source: Dissertation Abstracts International, Volume: 44-01, Section: B, page: 0026. / Thesis (Ph.D.)--The Florida State University, 1982.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75023 |
| Contributors | WILLIAMS, LARAMIE ANN., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 127 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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