Biology Commons^™

Mechanisms Of Condition-Specific Regulation Of Mrna Stability By Puf Proteins: From Yeast To Humans, Joseph Russo

Dissertations

RNA binding proteins regulate mRNA decay and translation, two key steps in the control of gene expression in cells. Controlling mRNA metabolism allows cells to respond rapidly to altering conditions by utilizing already available mRNA, bypassing the wait for newly transcribed mRNA. The Puf family of RNA binding proteins bind specific mRNAs through interactions with sequences located in the 3’ untranslated region (UTR). Puf proteins are conserved throughout eukaryotes and have diverse roles including stem cell maintenance, neuronal development, stress response and organelle biogenesis. In Saccharomyces cerevisiae, Puf proteins are conditionally regulated in response to the cells metabolic. Specifically, in …

Clarification Of The Systematics Of The Haploporoidea (Trematoda) With Descriptions Of New Genera And Species, Michael Jay Andres

Dissertations

The superfamily Haploporoidea Nicoll, 1914 comprises two families, the Atractotrematidae Yamaguti, 1939 and the Haploporidae Nicoll, 1914, and the subfamily Cadenatellinae Gibson et Bray, 1982. All members are parasites of the alimentary tract or gall bladder of marine, estuarine, and freshwater herbivorous fishes. Overstreet and Curran (2005a) provided a review of the Haploporidae and recognized four subfamilies, the Chalcinotrematinae Overstreet et Curran, 2005, Haploporinae Nicoll, 1914, Megasoleninae Manter, 1935, and Waretrematinae Srivastava, 1937. In a series of five publications, Blasco-Costa et al. (2009a-e) revised the Haploporinae and erected a fifth subfamily, the Forticulcitinae Blasco-Costa, Balbuena, Kostadinova, et Olson, 2009. The …

Fungal Contribution To Carbon And Nutrient Cycling In A Subtropical Freshwater Marsh, Rong Su

Dissertations

Despite the well-known occurrence of emergent standing litter in freshwater marshes, very little quantitative data is available concerning the functional role and contribution of fungal decomposers to litter decomposition or their impact on ecosystem scale carbon and nutrient cycling. In the present study, microbial respiration and seasonal biomass and production rates of fungal decomposers associated with standing plant litter were examined to assess the quantitative contribution of fungi to both fine scale litter decay processes and large-scale ecosystem carbon flow pathways in a subtropical Typha domingensis and mixed Cladium jamaicense/Juncus roemarianus freshwater marsh, respectively. In addition, the growth …

Online Versus Face-To-Face Biology: A Comparison Of Student Transactional Distance, Approach To Learning, And Knowledge Outcomes, Mary Erin Riggins

Dissertations

Community colleges are among many other institutions increasing course offerings online, but there is still some concern about the quality of online learning. Educator concerns, a lack of empirical evidence on biology courses offered online, and the need for an equal opportunity for education support the need for clarification of the quality of distance education in biology, especially in the community college setting. Student attitudes, approaches to learning, and performance should all be studied in order to formulate a better evaluation of the quality and effectiveness of online courses (Svirko & Mellanby, 2008).

The purpose of this study was to …

Elucidation Of The Role Of Auxin-Input Pathways In Auxin Homeostasis., Gretchen Spiess

Dissertations

Auxin is a phytohormone involved in cell elongation and division. Levels of indole-3-acetic acid (IAA), the most abundant auxin, are tightly regulated through biosynthesis, degradation, sequestration, and transport. Sequestration of IAA occurs in reversible processes by adding amino acids, polyol or simple alcohols, or sugars, forming IAA conjugates, or via a two-carbon elongation forming indole-3-butyric acid (IBA). These forms of auxin have decreased activity and are located in multiple organelles. Using a combination of molecular and genetic tools, I examined how these storage forms are working together to contribute to overall IAA levels and IAA response in both the model …

Community Organization Of Avian Malaria Parasites In Lowland Amazonia: Prevalence, Diversity, And Specialization In A Local Assemblage, Linda Maria Elenor Svensson

Dissertations

I characterized a lowland Amazonian assemblage of haemosporidian (“malaria”) parasites (Haemoproteus and Plasmodium) of understory birds by analyzing variation in prevalence (proportion of infected host individuals) among years and host species, documenting diversity of haemosporidian evolutionary lineages, and quantifying host specialization. Using standard molecular methods to screen for haemosporidia in 2488 individual birds from 104 species in the Tiputini Biodiversity Station, Ecuador, I found 21.7% to be infected. Prevalence ranged significantly among years and host species. Forty-five putative evolutionary lineages of haemosporidia were identified, by sequencing part of the cytochrome b (cyt b) gene. Based on a comparative analysis, among …

Identification Of Novel Natural Compounds With Anti-Breast Cancer Activities, Yusra Saif Al Dhaheri

Dissertations

Breast cancer continues to be the leading cause of cancer-related death in women worldwide. In this dissertation, natural compounds with anti-breast cancer activities were identified. We investigated the effect of Salinomycin, a potassium ionophore isolated from Streptomyces albus, on the survival of three human breast cancer cell lines MCF-7, T47D and MDA-MB-231. High concentrations of Salinomycin induced a G2 arrest, down regulation of survivin and triggered apoptosis. Interestingly, treatments with low concentrations of Salinomycin induced a transient G1 arrest at an earlier time and G2 arrest and senescence, associated with enlarged cell morphology, at a later time. There was also …

Population Genetics And Microbial Communities Of The Gopher Tortoise (Gopherus Polyphemus), Daniel Lyle Gaillard

Dissertations

The gopher tortoise, Gopherus polyphemus, is an endangered species living in the southeastern United States. The recent and drastic decline in tortoise numbers has resulted in a multi-faceted approach to conserve this species. I used a population genetic approach to determine the population structure, genetic diversity and barriers to gene flow at a broad, regional and local scale. Tortoises are divided into five distinct genetic populations at the broad scale, the central populations have the highest levels of genetic diversity and the Tombigbee, Mobile, Apalachicola, Suwannee and St. John’s Rivers appear to be barriers to gene flow. At the regional …

The Delivery, Speciation, And Fate Of Trace Elements In St. Louis Bay, Mississippi, Gopal Bera

Dissertations

Estuaries are dynamic regions in which there can be significant modification of the riverine flux of trace elements to the open ocean due to various geochemical, physical, and biological processes. Additionally, estuaries are often subject to anthropogenic inputs of trace elements. The first portion of this study investigated the source, behavior, and sediment interaction of anthropogenic stable cesium (Cs) in St. Louis Bay (SLB), MS. A consistent increase in stable Cs concentration was noticed in sediment cores starting from a period when a titanium dioxide refinery on SLB started operations. Weak correlation between Cs and clay percentage and strong correlations …

Assessing The Fishery And Ecology Of Sharks In The United Arab Emirates, Rima W. Jabado

Dissertations

Large scale shark population declines have been documented worldwide due to overexploitation and the lack of adequate management frameworks to conserve shark stocks. This study aimed at gaining an understanding of the national shark fishery and the trade in shark products from the United Arab Emirates (UAE). Data were collected from June 2010 to October 2012 through interviews with local fishermen, market and landing site surveys, fishery independent surveys, and stomach content analysis. Interviews with local fishermen (n=126) provided information on the fishery characteristics and established that sharks were increasingly targeted due to their high value in the global fin …