Immunocytochemical analyses have demonstrated that the Calvin cycle enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is predominantly localized in the pyrenoid region of chloroplasts of evolutionarily diverse algae. That Rubisco remains pyrenoid-localized at photosynthetically-saturating irradiance in the green alga Chlorella pyrenoidosa indicates a catalytic, rather than storage function for pyrenoid-localized Rubisco. This is further supported by the immunolocalization of Rubisco activase to the pyrenoids of two species of green algae. The exclusion of phosphoribulokinase from the pyrenoids of a red and a green alga indicates that pyrenoids do not possess the full complement of Calvin cycle enzymes. / Thylakoid lamellae traverse the pyrenoids of many algae. The absence of light-harvesting phycoerythrin and of photosystem (PS) II activity, but not PSI activity, from the intrapyrenoid thylakoids of the red alga Porphyridium cruentum indicates a structural and functional heterogeneity between these lamellae and those located in the chloroplast stroma. In contrast, the intrapyrenoid thylakoids of cryptomonads, algae whose chloroplast is thought to have evolved from red algae, possess both PSI and PSII protein complexes. These results are discussed with reference to Rubisco being mainly pyrenoid-localized in these algae.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.70337 |
| Date | January 1991 |
| Creators | McKay, R. Michael L. (Robert Michael Lee) |
| 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: 001274307, proquestno: AAINN74867, Theses scanned by UMI/ProQuest. |
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