Although mRNAs encoding the histone proteins are among the most abundant mRNAs in mammalian oocytes, the mechanism regulating their translation in these cells has not been identified. Most histone mRNAs are not polyadenylated but instead carry in their 3'-utr a highly conserved stem-loop structure. In somatic cells, the stem-loop binding protein (SLBP) is expressed during S-phase of the cell cycle and associates with the stem-loop of histone mRNAs promoting their processing and translation and thereby coordinating their expression to DNA replication. As histone mRNAs are abundant in immature oocytes which are in G2 of the cell cycle and in ovulated or mature oocytes which are in M-phase, I examined the expression and the regulation of histone mRNAs in immature and maturing mouse oocytes. First, I described SLBP expression during oogenesis and pre-implantation embryonic development. I showed that SLBP is present at low levels in the nucleus of the immature oocyte and accumulates significantly during maturation of the oocyte. At both stages, SLBP is the only stem-loop binding activity present. I showed that SLBP meiotic accumulation correlates with the adenylation of SLBP mRNA and is mediated by the presence of a cytoplasmic polyadenylation element in SLBP 3'-utr. Also, I demonstrated that histones are synthesized in the immature and mature oocyte and that the translation of a reporter mRNA bearing the histone 3'-utr increases dramatically during oocyte maturation consistent with the accumulation of SLBP. I specifically blocked SLBP accumulation using RNA interference and observed that both translation of the reporter mRNA and endogenous histone synthesis are significantly reduced. Moreover, SLBP-depleted eggs display a significant decrease in pronuclear size and in the total amount of histones detectable on their chromatin. Finally, I also showed that elevating the amount of SLBP in immature (G2) oocytes is sufficient to increase translatio

Thesis (Ph.D.)--University of Melbourne, Dept. of Zoology, 2004. / Typescript (photocopy). Includes bibliographical references (leaves 202-234).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [76]-96).

Mémoire (M.Sc.B.)--Université du Québec à Chicoutimi, 1990. / Document électronique également accessible en format PDF. CaQCU

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 69-71). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 69-71). Also available on the Internet.

AN ABSTRACT OF THE DISSERTATION OF RENEE A LOPEZ SWALLS, for the Doctor of Philosophy degree in PLANT BIOLOGY, presented on June 27, 2016, at Southern Illinois University Carbondale. TITLE: THE SPECIAL WALLS AROUND GAMETES IN CERATOPTERIS RICHARDII AND AULACOMNIUM PALUSTRE: USING IMMUNOCYTOCHEMISTRY TO EXPOSE STRUCTURE, FUNCTION, AND DEVELOPMENT MAJOR PROFESSOR: Dr. Karen S. Renzaglia Gametes are arguably the most important cells formed during the sexual life cycle of plants. The ancestral condition of gametes in land plants is the production of small motile sperm cells and larger non-motile eggs. Unique walls or cell matrices are formed during the development of these highly specialized cells, and are integral to their proper development and maturation. Yet, the polysaccharide composition, structural function, and metabolic processes of these special gamete cell walls remain unexplored beyond examination in the light microscope. Utilizing histochemical techniques coupled with immunocytochemical localizations with monoclonal antibodies (MAbs), I give a detailed survey of AGP and cell wall polymer distribution during male and female gametogenesis in the model fern, Ceratopteris richardi, and for comparison with both Ceratopteris and seed plants, I examined the same cell wall polymers during spermatogenesis in Aulacomnium palustre, a moss species. AGPs are abundant in the extraprotoplasmic matrix that surrounds differentiating sperm and egg cells in the fern, Ceratopteris richardii. During spermatogenesis, AGPs are speculated to regulate growth of flagella and cell morphogenesis through cell signaling via Ca+2 oscillations. Immunogold localizations revealed that AGPs are differentially expressed in the egg envelope in C. richardii. These glycoproteins are extremely abundant prior to fertilization but decrease substantially after fusion of the male gamete with the egg cytoplasm. Contrary to the AGP-filled matrix surrounding developing spermatids, developing eggs are bathed in (1,5)-α-L-arabinan pectins and not AGPs. Lastly, I examined the unique cell walls that are integral to sperm cell differentiation and release in both Ceratopteris and Aulacomnium. The preponderance of callose and hemicelluloses in the walls of the male gametes of Ceratopteris and Aulacomnium, respectively, and the importance of these polysaccharides in development are discussed. Taken together, the studies that comprise this dissertation advance significantly our understanding of cell wall dynamics during gametogenesis in early land plants.

This thesis presents results of the histological study of oogenesis in the nymphs of 5th instar, variously aged adult females of known age and adult females of Velia caprai ((Heteroptera: Gerromorpha: Veliidae) of unknown age that were collected in the field. Oogonia in the germarium and the first oocytes that are forming in previtellarium were observed in the nymphs of the 5th instar. Their vitellarium is empty. The first vitellogenetic oocytes appear in vitellarium of ovarioles at 7 days old adult females. Oocytes in advanced stage of vitellogenesis were observed at 25 days old adult females. The secretion of chorion starts at 42 days old adult females. Advanced stage of oogenesis (fully chorionated eggs) was found at 60 days old adult females, at adult females collected in the field, during the period September ? November (2009), and at adult females after overwintering. Females of Velia caprai reach sexual maturity before overwintering, their eggs can be fertilized by spermatozoa from own spermatheca. These females can lay eggs from autumn to the spring. After reaching sexual maturity of adult females, oogenesis of this species seems to be continual.

Juvenile hormone (JH) is the central hormonal regulator of life-history trade-offs in many insects. In Aedes aegypti, JH regulates reproductive development after emergence. Little is known about JH’s physiological functions after reproductive development is complete or JH’s role in mediating life-history trade-offs. By examining the effect of hormones, nutrition, and mating on ovarian physiology during the previtellogenic resting stage, critical roles were determined for these factors in mediating life-history trade-offs and reproductive output. The extent of follicular resorption during the previtellogenic resting stage is dependent on nutritional quality. Feeding females a low quality diet during the resting stage causes the rate of follicular resorption to increase and reproductive output to decrease. Conversely, feeding females a high quality diet causes resorption to remain low. The extent of resorption can be increased by separating the ovaries from a source of JH or decreased by exogenous application of methoprene. Active caspases were localized to resorbing follicles indicating that an apoptosis-like mechanism participates in follicular resorption. Accumulations of neutral lipids and the accumulation of mRNA’s integral to endocytosis and oocyte development such as the vitellogenin receptor (AaVgR), lipophorin receptor (AaLpRov), heavy-chain clathrin (AaCHC), and ribosomal protein L32 (rpL32) were also examined under various nutritional and hormonal conditions. The abundance of mRNA's and neutral lipid content increased within the previtellogenic ovary as mosquitoes were offered increasing sucrose concentrations or were treated with methoprene. These same nutritional and hormonal manipulations altered the extent of resorption after a blood meal indicating that the fate of follicles and overall fecundity depends, in part, on nutritional and hormonal status during the previtellogenic resting stage. Mating female mosquitoes also altered follicle quality and resorption similarly to nutrition or hormonal application and demonstrates that male accessory gland substances such as JH III passed to the female during copulation have a strong effect on ovarian physiology during the previtellogenic resting stage and can influence reproductive output. Taken together these results demonstrate that the previtellogenic resting stage is not an inactive period but is instead a period marked by extensive life-history and fitness trade-offs in response to nutrition, hormones and mating stimuli.

As an organism develops, multiple cellular processes need to occur in order to specify and organize tissue. One essential process is the establishment of cell polarity, which drives cell fate specification and stem cell differentiation. Another key process is programmed cell death, which is important for tissue remodeling and clearing damaged or diseased cells from the body. A loss in cell polarity can lead to defects in tissue organization and carcinogenesis. Defects in programmed cell death can lead to autoimmune diseases and cancer. However, hyperactive programmed cell death can lead to neurodegeneration. The Drosophila ovary, which is composed of germline and somatic cells, is an excellent model to study both cell polarity and cell death. In the germ cells, oocyte fate is specified and maintained through the asymmetric localization of cell cycle and cell polarity RNAs, proteins, and organelles, such as mitochondria, to and within the oocyte. Additionally the somatic follicle cells, which surround the germ cells, require a specific apical-basal polarity to function. During oogenesis, programmed cell death can be induced within the ovary to prevent oogenesis from maturing under low nutrient, high stress or crowded conditions. When this occurs, the germline is cleared from the ovary by a process known as engulfment. Somatic follicle cells surrounding the germline synchronously enlarge and engulf the corpses of the dying germline cells. It is unknown what triggers the enlargement of the follicle cells. Previous research has shown that the apical side of a follicle cell is heavily marked by cell polarity proteins, to specify the apical side away from the lateral and basal sides. Since many important genes regulating both cell polarity and engulfment are conserved between Drosophila and other eukaryotes, we can study the establishment and maintenance of cell polarity and its role during engulfment to obtain a better understanding of these processes in mammals and their relevance to diseases. This dissertation investigates the role of cell polarity in both the specification of oocyte cell fate, and the organization and enlargement of the follicle cells during engulfment in the ovary. / 2016-11-03T00:00:00Z