Young developing fruits of nasturtium (Tropaeolum majus L.) accumulate large deposits of non-fucosylated "storage" XG in periplasmic spaces of cotyledon cells. The only XG that is clearly fucosylated in these fruits Is the structural fraction (approx. 1% total) integrated into growing primary walk. Storage XG can be fucosylated by a nasturtium transferase in vitro, but this does not happen in vivo, even as a transitory signal required for secretion which would subsequently be cleaved to produce mature non-fucosylated storage XG in the periplasmic space. The two fucosylated subunits that are formed in vitro are identical to those found in structural XG in vivo. A block appears to develop in the secretory machinery of young cotyledon cells resulting in extended galactosylation and diversion of XG traffic to the periplasm without fucosylation. The primary walls buried beneath accretions of storage XG eventually swell and lose cohesion, probably because they continue to extend without incorporating components like fucosylated XG that are needed for maintaining wall integrity.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20813 |
| Date | January 1998 |
| Creators | Desveaux, Darrell. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001641286, proquestno: MQ44155, Theses scanned by UMI/ProQuest. |
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