Symbiotic interaction of Rhizobium with roots of legume plants leads to the formation of root nodules that are capable of reducing atmospheric nitrogen. In nodule cells, bacteria are always enclosed inside the peribacteroid membrane (pbm) which is derived from the plant cell plasma membrane. The pbm mediates all the molecular exchanges between the host plant and bacteria. The pbm of soybean (Glycine max) nodules induced by Bradyrhizobium japonicum was characterized for the presence of nodule-specific proteins (nodulins), which may be involved in some of the nodule-specific roles the pbm plays. The pbm was found to contain a number of nodulins, and most of them were shown to be of plant origin. The peribacteroid fluid (pbf) was also purified and shown to contain nodulins. Some of the pbf proteins were highly glycosylated. Immunological localization at the electron microscopic level has shown that pbm nodulins are inserted specifically in the pbm; almost none are detected in the plasma membrane (pm) of infected cells even though the pbm is derived from it. The amino acid sequences of three different pbm nodulins (nodulin-23, -24 and -26) do not share significant primary structure homology, neither do their tentative secondary structures. Our results do not preclude targeting based on pbm-nodulin-specific feature(s) of the proteins; but it is possible that pbm-specific localization is achieved by differential rates of membrane synthesis, or turnover, in pbm as compared to the plasma membrane.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75431 |
| Date | January 1987 |
| Creators | Fortin, Marc G. |
| 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 | Doctor of Philosophy (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000554087, proquestno: AAINL44295, Theses scanned by UMI/ProQuest. |
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