Biology Commons^™

Functional Characterization Of Putative Non-Specific Phospholipase C (Npc) In Arabidopsis Thaliana, Carlotta Antonetta Peters

Dissertations

Abstract Phospholipases are enzymes that hydrolyze phospholipids. In terms of the position of bond hydrolysis, phospholipases are classified into four major types: phospholipase C (PLC), phospholipase D (PLD), phospholipase A1 (PLA1) and phospholipase A2 (PLA2). PLC hydrolyzes phospholipids at the first phosphodiester bond, producing diacylglycerol (DAG) and a phosphorylated head group. Based on substrate specificity, PLC is divided into two distinctively different groups: phosphoinositide-specific phospholipase C (PI-PLC) and non-specific phospholipase C (NPC). There are six members of the NPC family in Arabidopsis, designated NPC1 through 6 that bears sequence homology to bacterial phosphatidylcholine hydrolyzing PLC (PC-PLC). However, their function remains …

Understanding The Origin And Rapid Diversification Of The Genus Anthurium Schott (Araceae), Integrating Molecular Phylogenetics, Morphology And Fossils, Monica Maria Carlsen

Dissertations

Anthurium is a strictly neotropical genus of Araceae ranging from southern Mexico to northern Argentina, including ca. 900 species and displaying an enormous variation in leaf morphology, growth habit, leaf venation pattern and inflorescence and fruit colors. Despite its immense diversity, its ecological importance in Neotropical forests, and a very long history of botanical collection, cultivation, and taxonomical research, Anthurium had been almost neglected in molecular phylogenies. This study combines chloroplast (trnG intron, trnH-psbA and trnC-ycf6 intergenic spacers) and nuclear (CHS first intron) DNA sequence data for 102 Anthurium species and uses maximum parsimony, likelihood and Bayesian phylogenetic analysis to …

The Relations Among Laterality, Cortisol, And Approach-Avoidance Behavior In Garnett's Bushbaby (Otolemur Garnettii), David Burton Hanbury

Dissertations

Many studies to date have demonstrated that approach and avoidance behaviors are processed asymmetrically in the brain and may be reflected in measures such as handedness. The purpose of this study was to extend work in primates on this topic to Garnett’s bushbaby, a prosimian species. Furthermore, to determine whether measures in addition to handedness relate to approach-avoidance behavior, lateralized differences in tympanic membrane temperature were assessed. Cortisol measures were also obtained to determine whether it was related approach-avoidance behavior and handedness. Eleven captive-born Garnett’s bushbabies (Otolemur garnettii) were evaluated for handedness and responsiveness to novelty. Moreover, the …

Transcriptional Regulation Of Nitrogenase And Identification Of A Fructose Transport System In Anabaena Variabilis, Justin Lynn Ungerer

Dissertations

Little is known about the regulation of nitrogenase genes in cyanobacteria. Transcription of the nifH1 and vnfH genes, encoding dinitrogenase reductases for the heterocyst-specific Mo-nitrogenase and the alternative V-nitrogenase, respectively, was studied using a lacZ reporter. Two promoters were found to be responsible for expression of nifHDK; a weak promoter within nifU1 and a strong promoter upstream of nifB (the nifB1 promoter). The region immediately upstream of vnfH did not drive expression of lacZ, however the region that included the promoter for the upstream gene, ava4055 did. Characterization of the previously reported nifH1 and vnfH transcriptional start sites by 5' …

Phylogenetics And Diversification Of Escallonia (Escalloniaceae), Felipe Zapata

Dissertations

Despite a large accumulation of evidence on the high richness of plant species in the mountains of South America, little is known about the historical underpinnings of this diversity. To contribute to our understanding of the origin and diversification of plant species in these mountains, I analyzed geographic patterns of variation in molecular and phenotypic characters for the genus Escallonia L.f. (Escalloniaceae), a group of shrubs widespread in montane habitats in South America. Molecular phylogenetic analyses using chloroplast and nuclear loci revealed i) that Escallonia is monophyletic, ii) a remarkable level of geographical phylogenetic structure, and iii) a widespread absence …

Molecular, Cellular And Systemic Effects Of Atrazine On The Xenopus Laevis Tadpole, Renee Maryanne Zaya

Dissertations

Atrazine is one of the two most commonly used herbicides in the US and it is the most studies are among the first to link physiological effects of atrazine to changes in tissue and gene expression in Xenopus laevis tadpoles. These studies provide the groundwork for future studies into the mechanisms behind responses to chemical stressors generating data resulting in a better understanding of how these chemicals affect us all. commonly found herbicide in ground water. As a result, a great deal of attention has been placed on its use and safety. It has also been implicated to play a …

Neuroprotective Effects Of A Nicotinic Acetylcholine Receptor Agonist And Modulator In The Rodent Retina, Kazuhiro Iwamoto

Dissertations

The purpose of this dissertation is to assess the potential neuroprotective effect of an alpha7 nAChR agonist, PNU-282987, and modulator, PNU-120596, in an in vitro model of excitotoxicity and an in vivo model of acute glaucoma. In in vitro studies, retinas obtained from Long Evans rats were cultured using various concentrations of the PNU compounds to analyze neuroprotection against glutamate-induced excitotoxicity. After 3 days in culture, RGCs were identified using an antibody against Thy 1.1, visualized using a fluorescent dye and quantified. In culture, glutamate significantly decreased the number of RGCs. However, if either PNU compound was introduced before the …

Phylogenetics, Morpohology, And Genomic Evolution In Physarieae (Brassicaceae), Sara Fuentes-Soriano

Dissertations

The mustard family (Brassicaceae) is economically important but the evolution of its morphology is not well understood. I investigate the evolution of morphological and genomic characters and calculate ancestral trait values in the Brassicaceae within a phylogenetic context using the tribe Physarieae as a model system. Physarieae are a unique and diverse group of American mustards characterized by multi-aperturate pollen. Phylogenetic analyses of DNA sequences (chloroplast ndhF and nuclear ITS and LUMINIDEPENDENS) were used to test the monophyly and explore evolutionary relationships of Physarieae. The phylogenetic inferences were used to identify morphological traits to delimit the tribe, to interpret the …

Development Of A Methodology To Attain High Levels Of Storage Proteins In Cassava Tuberized Roots And Its Implications, Mohammad Abhary

Dissertations

Cassava (Manihot esculenta Crantz.) is a member of the Euphorbiaceae family, cultivated in the tropics and subtropical areas as a staple food crop for more than 700 million people around the world. The starchy storage roots of cassava are rich in calories and deficient in all other nutrients, cassava meals has the lowest of all sources of dietary protein. Severe protein deficiencies and malnutrition problems are common among those who rely on cassava as their daily meal. Although cassava is ranked the fifth most important crop in the world, the research on this crop is very limited. Among the limited …

Avian Developmental Endocrinology: The Effects And Role Of Yolk Hormones, Sibling Dynamics, And Life-History, Corinne Patricia Kozlowski

Dissertations

Inter-specific variation of the endocrine system is an underlying component for variation in avian life-history. Females deposit hormones into the yolks of their eggs, and embryonic exposure affects nestling phenotype. Hormones are also produced endogenously by developing nestlings, further influencing their behavior and physiology. This dissertation examines the role of the endocrine system in development by focusing on several different avian taxa. Yolk hormone concentrations often vary across the laying order and may mediate hatching asynchrony. These patterns were characterized in two species that lay asynchronously hatching clutches: Eastern screech owls (Megascops asio) and cockatiels (Nymphicus hollandicus). The patterns described …

Life History And Habitat Use Of The Juvenile Alabama Shad (Alosa Alabamae) In Northern Gulf Of Mexico Rivers, Paul Fraser Mickle

Dissertations

The Alabama shad, Alosa alabamae, is an anadromous species that is in decline and has seen extirpations from impoundments as well as decreased water quality. Alabama shad live in the Gulf of Mexico and ascend Northern Gulf of Mexico Drainages to reproduce early in the year (January-May). The juveniles spend the majority of the year in these freshwater systems before emigrating out to the Gulf of Mexico as late as December.

This dissertation focuses on the juvenile life stages that occur within the Northern Gulf of Mexico drainages. Spawning conditions of the river, as well as the habitat and diet, …

Folate Receptor-Targeted Delivery Of Small Interfering Rna To Cancer Cells, Yilin Zhang

Dissertations

The vitamin folic acid (folate, FA) has been extensively explored as a targeting ligand to deliver a variety of diagnostic/prognostic/therapeutic agents into various tumors through the assistance of its receptor – the folate receptor (FR). FR is over-expressed in many types of human cancer and can mediate internalization of FA-conjugates through an endocytic pathway. The discovery of small interfering RNA (siRNA), which is cable of inducing potent gene silencing in a sequence-specific manner, provides an excellent molecular tool to suppress aberrant gene expression in malignancies, and therefore siRNA has the potential to revolutionize cancer therapeutics. Towards the goal of developing …

Geological And Ichthyological Investigations Into Palaeodrainage Hypothesis For The Tennessee River, Andrea Karen Persons

Dissertations

The course of the ancestral Tennessee River has been debated in both the geological and biological literature for over 100 years. Several of the proposed courses for the ancestral Tennessee place its course across the state of Mississippi. Geochemical analysis of sedimentary rocks in the Pascagoula River basin supports these hypotheses suggesting that the rocks in the Pascagoula basin were derived from the Highland Rim of Tennessee and northern Alabama, while geochemical analysis of rocks from the Pearl River basin point to deposition from a mixture of sources including the ancestral Mississippi River and perhaps the ancestral Tennessee. To delve …

Regulation Of Biofilm And Antibiotic-Resistance By The Modulator Of Sara (Msa) In Staphylococcus Aureus, Antony Schwartz

Dissertations

Staphylococcus aureus is an important human pathogen that is the causative agent of life-threatening diseases such as endocarditis and osteomyelitis. The ability of S. aureus to thrive as a successful pathogen can be partially attributed to its ability to form biofilm. Biofilm is an extracellular polysaccharide, protein, and DNA-based slime layer that protects the bacterial community. The global regulator sarA is essential for biofilm formation. Since the modulator of sarA (msa) gene regulates several virulence factors and is required for the full expression of sarA, the capacity of the msa mutant to form a biofilm was examined. The mutation of …

Toxicogenomics Analysis Of Non-Model Transcriptomes Using Next-Generation Sequencing And Microarray, Arun Rawat

Dissertations

With the advent of next generation technologies like Roche/454 Life Sciences that require low cost and less time for sequencing will help in providing a workable draft of non-model species genomes. Availability of high throughput microarray technologies for gene expression profiling provides low-cost tools for investigation of highly-integrated responses to various stimuli. These advancements along with bioinformatics processing have led to an increasing number of non-model species having well-annotated transcriptomes. The project focuses on the life cycle of development, functional annotation, and utilization of genomic tools for the avian wildlife species to determine the molecular impacts of exposure to munitions …

A Comprehensive Uncertainty Analysis And Method Of Geometric Calibration For A Circular Scanning Airborne Lidar, Michael Oliver Gonsalves

Dissertations

This dissertation describes an automated technique for ascertaining the values of the geometric calibration parameters of an airborne lidar. A least squares approach is employed that adjusts the point cloud to a single planar surface which could be either a narrow airport runway or a dynamic sea surface. Going beyond the customary three boresight angles, the proposed adjustment can determine up to eleven calibration parameters to a precision that renders a negligible contribution to the point cloud’s positional uncertainty.

Presently under development is the Coastal Zone Mapping and Imaging Lidar (CZMIL), which, unlike most contemporary systems that use oscillating mirrors …

The Role Of Puf3p And Puf4p In The Regulation Of Mrna Decay In Yeast Saccharomyces Cerevisiae, Florencia Andrea Lopez Leban

Dissertations

Proper regulation of gene expression at a cellular level is required in all organisms for their successful adaptation and survival to physiological or environmental changes. In eukaryotes, a convenient way of regulating gene expression is achieved by post-transcriptionally adjusting the decay rates of different mRNAs. The Puf family of proteins in yeast belong to a widespread group of eukaryotic RNA-binding proteins that regulate the lifespans of target mRNAs by sequence specifically binding to 3' untranslated regions (UTRs) and modulating their decay rates. For example, the yeast Puf3 protein binds the COX17 3' UTR, stimulating its deadenylation and subsequent decay. However, …

Information Acquisition And Sociality Among Migratory Birds, Zoltán Németh

Dissertations

Information use is a key feature of adaptive behavior: the better informed an individual, the better it is able to adjust its behavior to meet the demands of a variable world. Therefore, most animals attempt to reduce environmental uncertainty by gathering information when it is available. However, tracking unpredictable ecological factors may carry costs as individuals invest valuable time and energy in the process of information acquisition. Social learning (i.e., use of social information inadvertently produced by other individuals) enables the individual to gain rapid and more complete assessment of its novel environment. This process may be particularly important for …

Patterns Of Diversity, Zoogeography, And Ecological Gradients In Honduran Freshwater Fishes, Wilfredo Antonio Matamoros

Dissertations

Nineteen major river drainages across Honduras were sampled from 2005-2009 in order to understand Honduran geographical patterns of freshwater fish distribution, to delineate the Honduran freshwater fishes ichthyographical provinces, and to understand patterns of species assemblage at the drainage level. A total of 166 species of freshwater fishes were sampled, a 64% increase over previously published reports. Eight species belong to primary freshwater families, 47 to secondary, and 111 to peripherals. In order to understand the species-drainages relationships, a presence-absence matrix was built for the 19 major drainages and 55 primary and secondary freshwater fishes. Correspondence and cluster analysis clearly …

Algal Community Structure In Water Bodies Of Mississippi: The Role Of Environmental Factors In Its Spatial And Temporal Dynamics, Nestor Raul Anzola

Dissertations

A meta-analysis was done on studies that included six major taxa groups: Cyanobacteria, Chlorophyta, Chrysophyta (primarily diatoms), Euglenophyta, Pyrrophyta, and Rhodophyta and six aquatic habitats of Mississippi to determine the abundance and richness of the algal community and to identify relevant environmental drivers of algal assemblage composition. Twenty algae data sets on small order streams, large streams and rivers, lakes and reservoirs, fish production ponds, brackish water, and marine water were analyzed. Chlorophyta was dominant in lakes and reservoirs and was the most diverse taxa in the phytoplankton of small order streams and large streams and rivers. Cyanobacteria were the …

Individuals Differences In Exploratory Behavior Of Prairie Voles, Microtus Ochrogaster, Danielle N. Lee

Dissertations

Individual differences in behavior are significant because they serve as the substrate for natural selection. Within the Behavioral Syndromes framework, researchers study individual differences in behavior of animals. Behavioral Syndromes are defined as correlations between behaviors in different environmental contexts or testing situations. In this study, I examined the effects of litter size and sex ratio, familial relationships, and age and sex on exploratory behavior of prairie voles, Microtus ochrogaster. Exploratory behavior, defined as spontaneous behavioral responses to unfamiliar stimuli, was examined in three novel situations: an open-field with novel objects, a two-way novel choice apparatus, and a complex maze. …

Development Of Representative Species-Level Molecular Markers And Morphological Character Analysis Of Leucothoid Amphipods (Crustacea: Amphipoda), Kristine Nicolle White

Dissertations

Leucothoid amphipods were investigated using morphology and molecular rDNA gene sequence fragments. The morphological diagnostic characters for traditional taxonomy have been clarified, a molecular marker for representative species has been developed, and one of the current anamorph-leucomorph connections has been confirmed with molecular sequence data. Ultimately this study has combined traditional morphological and modern molecular methods to clarify the taxonomy and to propose a preliminary phylogeny of the Leucothoidae. Analysis of 18S rDNA gene fragments from 13 species in two genera supported the current morphological species designations and the separation of the family into two clades. Combined analysis of 18S …

Systematic Revision Of The Kalliapseudidae (Crustacea: Peracarida: Tanaidacea) And The Population Genetic Structure And Phylogeography Of A Species Along The Southeastern And Gulf Coasts Of North America, David Thomas Drumm

Dissertations

The Kalliapseudidae is a family of shallow burrow-dwelling marine and estuarine tanaidaceans. There are currently 39 known species of 12 genera and three subfamilies. They are primarily circumtropical in distribution; however, several species are found in temperate waters. The phylogeny of Kalliapseudidae is assessed to test the monophyly of currently accepted subfamilies and genera, based largely on examination of material loaned from various museums and institutions. Multiple exemplars from other apseudomorph families were also included in the ingroup to test the monophyly of the family. Parsimony analyses included 41 terminal taxa and 64 binary and multistate morphological characters. Analyses based …

High-Throughput Screening Studies Of Inhibition Of Human Carbonic Anhydrase Ii And Bacterial Flagella Antimicrobial Activity, Albert A. Barrese Iii

Dissertations

Complete abstract attached as supplemental file.

Conservation And Ecology Of The Yellow-Blotched Sawback (Graptemys Flavmaculata), William Winsyl Selman Ii

Dissertations

The role of species conservation is becoming increasingly important due to the mounting pressures from humans on habitats and populations of organisms. This is particularly evident in riverine ecosystems throughout the world where the human demand for freshwater resources is increasing, and consequently, the number of imperiled aquatic organisms is also growing. The seven chapters of this dissertation primarily focus on the Yellow-blotched Sawback, Graptemys flavimaculata, an endangered riverine turtle that is endemic to the Pascagoula River system of southeast Mississippi, USA. At the population level, we aimed to study the impacts of Hurricane Katrina on two study populations within …

Determining The Relationship Of Human Enteric Viruses In Clinical, Wastewater, And Environmental Samples Utilizing Molecular And Cell Culture Techniques, Jacquelina Susann Williams Woods

Dissertations

This study was the first to examine five significant enteric viruses in human fecal material, sewage, and oysters to show a genetic relationship between human enteric viruses and different sample matrices. Fecal samples were collected from an area hospital and examined for norovirus genotype I (NoV GI), norovirus genotype II (NoV Gil), hepatitis A virus (HA V), adenovirus (ADV), and enteroviruses. During this study, sewage samples were collected from a Waster Water Treatment Plant (WWTP) in Mobile, ALand oyster sentinels were placed at 0.1 nautical miles (nm) (station 1 ), 0.2nm (station 2}, 1.5nm (station 3), and 4nm (station 4) …

Relationships Between Particle Properties And Scattering In Coastal Waters Of The Northern Gulf Of Mexico Influenced By The Mississippi River, Bruce Alan Spiering

Dissertations

This study was conducted to determine how the characteristics of an assemblage of suspended particles, including their composition and size affect the relationship between the optical scattering coefficient b (m-1), and the dry mass of the particles in suspension. Knowledge of the scattering to total suspended matter (TSM) ratio, i.e. the mass specific scattering coefficient b* (m2/g), is important because the light detected by optical imaging sensors used for remote sensing is the light that has been scattered by particles back through the water surface. If this ratio is not known or varies within the region of interest, accurate estimates …

Remote Sensing Of Harmful Algal Blooms In The Mississippi Sound And Mobile Bay: Modelling And Algorithm Formation, Dan Martin Holiday

Dissertations

The incidence and severity of harmful algal blooms have increased in recent decades, as have the economic effects of their occurrence./The diatom Pseudo-nitzschia spp. caused fisheries closures in Mobile Bay during 2005 due to elevated levels of domoic acid. In the previous 4 years Karenia brevis counts of >5,000 cells L"1 have occurred in Mobile Bay and the Mississippi Sound. Population levels of this magnitude had previously been recorded only in 1996. Increases in human populations, urban sprawl, development of shoreline properties, sewage effluent and resultant changes in NP ratios of discharge waters, and decline in forest and marsh lands, …

Conservation Genetics And Systematics Of Several Turtles Species In The Southeastern United States, Joshua Robert Ennen

Dissertations

Chelonians (i.e., turtles) are an imperiled group of reptiles with about 66% of the recognized species listed as threatened by the IUCN. Most chelonian species have a unique set of life history traits (i.e., longevity, delayed sexual maturity, and low juvenile survivorship), which makes their populations exceedingly sensitive to increases in adult and juvenile moralities. With numerous anthropogenic effects (e.g., habitat alteration, exploitation, and over harvesting) negatively influencing mortality rates, chelonians have experienced global precipitous declines and extinctions.

This dissertation focuses on species within two chelonian genera, Gopherus and Graptemys. Although these two genera are vastly different ecologically, they are …

Maternally Derived Antibodies In Avian Eggs And Offspring: Ecology, Life History, And Development, Brianne Ashley Addison

Dissertations

Mothers can alter offspring phenotypes through a variety of indirect effects, including the deposition of nutrients, hormones, and defense proteins in to the egg. Defense proteins, and antibodies in particular, may be tremendously important for neonatal defense against pathogens and the direction of resources into growth rather than immune responsiveness. Moreover, maternally derived immunoglobulins have been proposed to have an imprinting effect on the development of humoral immunity. In my dissertation, I explored a variety of ecological, life history, and developmental factors that could contribute to the evolution of yolk antibody allocation in a variety of avian species. In the …