Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--Washington State University, May 2007. / Includes bibliographical references.

Flowers are the organs for sexual reproduction in angiosperms. Gametogenesis in floral organs leads to formation of sperms and eggs and their fertilization forms a zygote that develops into a new plant. Gametogenesis and embryogenesis involve precisely regulated biological processes controlled by complex networks of genes and pathways. In this study, AtANA1, which was identified as a redox sensitive protein in previous study, was found to be essential for embryogenesis and also plays an important role in both male and female gametogenesis. Without a functional AtANA1, embryo development is arrested after the first cell division of the zygote. The ana1 mutation also causes arrest in different steps of male and female gametogenesis. Aborting pollen and embryos caused by the ana1 mutation exhibit enhanced accumulation of reactive oxygen species and DNA fragmentation, marks of programmed cell death. Presence of aborting ana1 pollen was also found to lead to abortion of wild type pollen in the same anther, raising a possibility that the aborting ana1 pollen might release a death signal. ANA1 could be involved in an oxidative stress signaling pathway, and loss of its function triggers death of gametophytic and embryonic cells. Another important protein involved in Arabidopsis reproductive processes is PUB4, an E3 ubiquitin ligase. The pub4 mutation was previously found to cause abnormal enlargement of tapetal cells and incomplete degeneration of the tapetum layer, resulting in a defect in pollen release and conditional male sterility. In this study, we characterized PUB4’s role in controlling floral meristem determinacy. The pub4 mutation causes formation of ectopic floral organs inside of carpels/siliques. It was found that the pub4 mutation leads to ectopic expression of WUSCHEL, an important regulator which is essential for maintaining shoot apical meristem and floral meristem, which could be responsible for the flower-in-flower phenotype. PUB4 appears to work additively with AGAMOUS (AG) to control appropriate expression of the WUS gene. Three extra large G proteins (XLGs) in Arabidopsis, which interact with PUB4, also play roles in controlling tapetal cell enlargement and degeneration. However, XLGs might not function in floral meristem determinacy.

Thesis (Ph. D.)--University of Chicago, Dept. of Geophysical Sciences, August 1999. / Includes bibliographical references. Also available on the Internet.

Not available / text

Proefschrift -- Utrecht. / "Liste bibliographique": p. [16]. "Littérature": p. [77]-123.

Proefschrift -- Utrecht. / "Liste bibliographique": p. [16]. "Littérature": p. [77]-123.

No description available.

Thesis (Ph. D.)--University of Oklahoma, 1991. / Includes bibliographical references (leaves 135-150).

The fermentation of African locust beans was studied. These beans in the raw state are inedible but may be rendered palatable by fermentation. Both their texture and taste are thereby considerably improved. / The beans were first processed by boiling and dehulling. They were then fermented at 37 (+OR-) 2(DEGREES)C in stationary fermentor units. Physico-chemical, microbiological, biochemical and enzymological investigations were carried out on the substrate undergoing spontaneous fermentation and on radappertized (11 kGy) controls. Reductions in carbohydrate (52%), protein (12%) and energy (9%) contents, as obtained from the mass and energy balances, occurred during fermentation. The physico-chemical changes were due to the action of extracellular carbohydrases and proteases produced by a Bacillus spp. Pure culture inoculation with the Bacillus spp. gave the fermented product within 24 h in contrast to the normal 72 h fermentation period. / Both pH and titratable acidity increased during fermentation. Ammonia was produced as a result of proteolysis. Fermented African locust beans are rich in both protein and fat and feature in the diet of a large proportion of the 200 million people in West Africa.