Anti-tubulin immunofluorescence microscopy was used to study the structures involved in the first cell cycle in the fertilized sea urchin egg and the regulation of microtubule assembly following fertilization. / Four different microtubule-containing structures were observed in the egg cytoplasm at different times during the first cell cycle. The unfertilized egg was found to be devoid of microtubules. Immediately after fertilization, the sperm aster forms. This structure is transient, and is followed in sequence by the monaster, the streak, and the mitotic apparatus. The possible functions of each of these structures was investigated. / The finding that the unfertilized egg does not contain any polymerized microtubules presented a perfect system to study the regulation of microtubule assembly in vivo. The formation of microtubules in vivo was studied in relation to DNA synthesis cycles, the presence or absence of centrioles, and the Ca('++)-fluxes and pH changes which accompany fertilization. It was determined that of these variables, the change in intracellular pH that accompanies fertilization is absolutely essential for microtubule assembly to commence in the egg cytoplasm. / Investigations were carried out to determine the target or targets which were affected by the pH shift and were then subsequently responsible for making the egg cytoplasm conducive to supporting microtubule assembly. Ca('++)-sensitivity experiments were carried out on the sperm aster microtubules at various pH's and it was found that the microtubules themselves were not made more resistant to Ca('++) ions because of the pH change. From this it was concluded that the change in pH does not act directly on microtubules to support microtubule assembly. The cytoplasmic component that is the target of the pH shift remains to be determined. / Source: Dissertation Abstracts International, Volume: 46-04, Section: B, page: 1051. / Thesis (Ph.D.)--The Florida State University, 1985.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75573 |
| Contributors | BALCZON, RONALD DAVID., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 269 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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