Life Sciences Commons^™

The Role Of Wnt Signaling In Development Of The Ophthalmic Trigeminal Placode., Rhonda Nicole Lassiter

Theses and Dissertations

Cranial placodes are ectodermal regions that contribute extensively to the vertebrate peripheral nervous system. The development of the ophthalmic trigeminal (opV) placode, which gives rise only to sensory neurons of the ophthalmic lobe of the trigeminal ganglion, is a well-studied model of sensory neuron development. While key differentiation processes have been characterized at the tissue and cellular levels, the molecules governing opV placode development have not been well described. This study identifies the canonical Wnt signaling pathway as a regulator of opV trigeminal placode development. Introducing dominant-negative TCF and dominant-active β-catenin expression constructs by in ovo electroporation, we have manipulated …

Synthesis And Optical Properties Of Four Oligothiophene-Ruthenium Complexes And Synthesis Of A Bidentate Ligand For C-F Bond Activation, Joseph S. Bair

Theses and Dissertations

Photovoltaic cells and fluorescence sensing are two important areas of research in chemistry. The combination of photon-activated electron donors with electron acceptors provides a strong platform for the study of optical devices. A series of four oligothiophene-ruthenium complexes has been synthesized. Variation in oligothiophene length and bipyridine substitution allowed comparison of these variables on electronic properties. The longer oligothiophenes display lower energy absorption and emission compared to the shorter ones. Aromatic conjugation appears more complete with para-, rather than meta-, substitution. Oligothiophenes and Ru(bpy)32+ are highly fluorescent individually, but fluorescence is quenched when connected. Bonds of carbon to fluorine are …

The Tangled Web Of Community Ecology: Making Sense Of Complex Data, Monica Lynn Beals

Doctoral Dissertations

Ecological communities are governed by complicated processes that give rise to observable patterns. Making sense of these patterns, much less inferring the underlying processes, has proved challenging for several reasons. Manipulative experiments in natural communities may not be feasible due to large numbers of variables, lack of adequate replication, or the risk of undesirable consequences (e.g., introducing an invasive species). The multivariate nature of ecological datasets presents analytical problems as well; many statistical techniques familiar to ecologists have difficulty handling large numbers of potentially collinear variables. I present results from three studies of spider communities in which I employ a …

Avian Community Ecology: Patterns Of Co-Occurrence, Nestedness, And Morphology, Michael David Collins

Doctoral Dissertations

A central tenet of the competition paradigm is that community structure is governed by deterministic rules. The competition paradigm pervades nearly all subdisciplines and extends to the broadest, deepest questions in ecology. To determine whether patterns of co-occurrence, nestedness, and morphology in avian communities are consistent with a competition hypothesis, I use null models to compare observed patterns to patterns expected in the absence of competition.

I use presence-absence matrices of birds in three archipelagoes to test whether species exhibit exclusive distributions. Congeneric birds co-occur significantly less frequently than predicted in two archipelagoes, consistent with a competition hypothesis. However, when …

Studies On Cytochrome P450 Genes In Drosophila Melanogaster: Relationship Between Over Expression And Ddt Resistance, And Xenobiotic Induction, Srilalitha Kuruganti

Doctoral Dissertations

Cytochrome P450 monooxygenases (CYPs), are involved in the metabolism of a diverse group of endogenous and xenobiotic compounds. In insects, CYPs are involved in conferring resistance against insecticides. In Drosophila, the expression of Cyp6a2, Cyp6a8, Cyp6g1, Cyp6w1 and Cyp12d1 is higher in the resistant compared to susceptible strains. Recent study by Daborn et al (2002, Science, 297, 2253-2256) showed that Cyp6g1 alone can confer resistance phenotype. The aim of my first objective was to re- examine this claim and second to examine the effect of common xenobiotic compounds on the transcriptome of Drosophila.

In first objective, six strains …

An Integrated Experimental And Computational Approach To Proteomics: Scaling From High Resolution Qualitative Analysis To Quantitative Measurements With Confidence Evaluation, Chongle Pan

Doctoral Dissertations

As a component of systems biology, proteomics aims to characterize the entire protein complement of an organism, including qualitative identification of protein types and quantitative measurement of protein abundance changes as a function of different cellular states. This dissertation presents an integrated experimental and computational approach to improve proteomic measurements, including qualitative measurements using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and quantitative measurements with statistically derived confidence evaluation.

Although FT-ICR-MS provides high-performance mass measurements, its potential has not yet been fully explored for proteomics applications. A novel tandem mass spectrometry method was developed for FT-ICR-MS to obtain sequence …

Cross-Species Comparison Of Spermatocyte Responses To Induced Dna Damage: The Laboratory Mouse And Drosophila Melanogaster, Shannon Marie Matulis

Doctoral Dissertations

Maintenance of genomic stability is of crucial importance for all organisms. Cells are continually exposed to exogenous and endogenous agents that can damage DNA. Of special interest is the manner in which male germ cells respond to and repair induced DNA double strand breaks (DSBs), as the propagation of cells carrying damaged DNA can lead to the production of heritable mutations, genetic diseases, and sterility. In addition, treatment of male germ cells with DNA damaging agents, such as many chemotherapeutic drugs, can ultimately result in infertility. This research focused on investigating the mechanisms by which male germ cells, specifically those …

Physicochemical Characterization And Antibacterial Potential Of Naturally-Occurring Antimicrobial Polypeptide-Bearing Phospholipid Liposomes Against The Foodborne Pathogens Listeria Monocytogenes And Escherichia Coli O157:H7, Thomas Matthew Taylor

Doctoral Dissertations

Liposomes are spherical bilayer vesicles formed from dispersion of polar lipids in aqueous solvents and have been studied for their ability to act as drug delivery vehicles by shielding reactive or sensitive compounds prior to release. In the food industry, liposomes have been used to deliver food flavors and nutrients; more recently they have been investigated for their ability to incorporate food antimicrobials.

Thermal stability of liposomes, in the presence and absence of nisin, was evaluated using differential scanning calorimetry (DSC) and low-intensity ultrasonic spectroscopy (US). Observed phase transition temperatures for liposomes measured via DSC and US were in close …

Molecular Screening Of Azoreductase Gene And Its Activity In Human Intestinal Bacteria, Syndia S. Todd

McCabe Thesis Collection

The intestinal microflora are capable of performing a wide variety of metabolic transformations. "The intestinal bacteria can enhance the function of the entire gastrointestinal tract, protect against pathogenic, maintain the vital chemical balance of the gastrointestinal system, and produce needed vitamins and hormones" (http;//www.upwardquest.com/crit2.html). Some of the products of this metabolism have been associated with carcinogenic processes, such as cancer, tumor formation, gastrointestinal disease, and infections. The ability of human intestinal microbes to interact with metabolites directly or after recirculation may contribute toward different toxicological disorders and disease.

The purpose of this study is to characterize and isolate the azoreductase …

Enhanced Print Performance Of Water-Based Rotogravure Inks Through Rheological Balance, Rurou Mai

Masters Theses

Water-based inks have been of more and more interest to the printing and ink industry. Compared with solvent-based inks, water-based inks have more complex formulations because of their higher surface tensions, lower drying speed, foaming problems, pH balance, and different rheological properties. This work explores the significant effects of various rheology modifiers, including non-associative and associative thickeners, on the rheological properties of a water-based rotogravure ink system. Particular emphasis is given to thickening efficiency, pH stability, particle size, system compatibility, temperature stability, and printability on vinyl substrates. Wire-wound lab rods and a Moser Sheet-fed Gravure Proofing Press were employed to …

Conservation Taxonomy Of The Cuban Parrot: Morphological, Plumage And Flight Call Variation, M. Bryant J. Reynolds

Loma Linda University Electronic Theses, Dissertations & Projects

Conservation taxonomy, the study of organismal classification to clarify conservation priorities, seeks to define species and subspecies limits. Allopatric populations, such as those present on islands, pose special challenges to identifying taxonomic boundaries that can be be addressed using diagnostic criteria. Because some of the island populations of Cuban Parrot (Amazona leucocephala) are highly endangered, the five recognized subspecies need careful reevaluation. I measured 18 morphological and plumage characters from 188 museum specimens representing the six extant and one extirpated island populations. I also examined 11 spectrographic characters from the flight calls of 23 parrots representing all six …

An In Vitro Model Of Ovarian Cancer: Studying The Effects Of Talc And Pycnogenol®, Amber Renée Buz'zard

Loma Linda University Electronic Theses, Dissertations & Projects

Ovarian cancer is the sixth most common cancer and accounts for more deaths than any other cancer of the female reproductive system. The American Cancer Society has suggested that poor diet, talc and industrial pollutants may increase the risk of developing ovarian cancer. Talc is ubiquitous and concern is raised about its safety, role as a possible carcinogen and known ability to cause irritation and inflammation. Due to the silent nature of ovarian cancer, chemoprevention is a high priority. The most useful chemopreventive compounds will inhibit, delay or reverse carcinogenesis, and can be taken for long periods of time with …

The Role Of Prolactin And Its Antagonist In Her2/Neu Tumorigenesis, Michele Scotti

All Dissertations

Purpose: To study the role of prolactin (PRL) and its antagonist, G129R, in HER2/Neu tumorigenesis. Specifically, to investigate the interaction between the oncogene HER2 and the PRL receptor (PRLR) signaling pathways for designing effective combinational therapeutics for breast cancer.
Experimental Design: The combination effects of G129R and an anti-HER2 antibody, Herceptin, were tested against HER2-overexpressing human breast cancer cell lines, T-47D and BT-474, using cell based assays and xenografts established in athymic mice. Furthermore, four different bitransgenic mouse lines co-expressing the murine version of HER2 and PRL or G129R were generated. The mammary tumor incidence, characterization of mammary gland development, …

Surface Topography Contribution To Rfid’S Tags Efficiency Related To Resistivity, Mario A. Cruz

Masters Theses

The Radio Frequency Identification (RFID) is one of the new technologies with more vision and acceptance oriented to the distribution and storage industries. The RFID is a technology that can be used to identify, track and store information about groups of products, individual items, or product components, using radio waves. The RFID device needs an antenna in order to receive a signal and transmit information. The stamping process applied today to produce the RFID antenna works with foil or copper. These etched metal RFID tags offer good benefits, but the production cost is too high to achieve a widespread implementation. …

Caustic Treatment Of The Pulp: Caustic Recovery By Reverse Osmosis, Miroslav Suchy

Masters Theses

The benefit of caustic treatment on changing cellulose properties has long been known. When the treated pulp is later intended for use in personal or in health care product industries, it is important that all residual chemicals are removed and that the pure cellulose or carbohydrate portion of the pulp remains. The removal is usually facilitated by washing. Due to the low caustic concentration in the washing filtrates the removal of the excess water by standard techniques such as evaporation would not be economical.

The main objective of this investigation was to evaluate the concept of using reverse osmosis for …

Diel And Tidal Rhythms Of Emercenge Events Based On Acousitc Observations In A Shallow Estuary, Mei Sato

Electronic Theses and Dissertations

Field observations of emergence events by epibenthic animals were conducted with two Tracor Acoustic Profiling Systems (TAPS) in the Damariscotta River estuary, Maine, in fall 2005 and summer 2006. Spectral analysis revealed that periodic temporal variability of the acoustic signals was concentrated at four periods. One was the solar day (24 h) and the other three were lunar tidal periods of 25.82 (diurnal or Oi), 12.42 (semidiurnal or M2) and 6.21 h (half the semidiurnal period). The mysid Neomysis americana showed strong nocturnal migration patterns of water-column activity during its peak summer emergence season, regulated by the diel cycle. Toward …

Engineering Calpastatin To Develop A Sensor To Detect Active Calpain, Lisa M. Vanhooser

Electronic Theses and Dissertations

Calpains, Ca²⁺-activated cysteine proteases are essential for early embryonic development and function in signal transduction, cell adhesion, and apoptosis. Calpains also contribute to cataractogenesis, myocardial infarctions, and neurodegenerative diseases such as Alzheimer's. The various methods currently available to demonstrate these roles do not directly identify spatial or temporal activation of calpain in cells. Therefore, a tool to detect active calpain in situ will be useful. Calpastatin is the ubiquitous, endogenous inhibitor that specifically binds the active conformation of the conventional calpains. Calpastatin consists of four homologous domains each containing three subdomains A, B, and C. The crystal structure …

Responses To Salinity Of Color Polymorphs In Two Populations Of The Sea Star, Pisaster Achraceus, Viren Johann Perumal

Loma Linda University Electronic Theses, Dissertations & Projects

Pisaster ochraceus was analyzed to determine if varying salinities, animal color, or location affect the physiology of these sea stars. The three responses analyzed were aerobic respiration, ammonia excretion, and self-righting. The tested variables included two different color morphs (orange and purple) of P. ochraceus, two different locations (open coast and inland straits) in Washington State, and three salinities (22, 30, and 40 psu).

Wet mass-specific oxygen consumption rates were not significantly affected by color, location, or salinity, and Dry mass-specific oxygen consumption rates showed no significant differences for main effects, but a three-way interaction was identified. Similarly, ammonia …

A Quantitative Analysis Of Morphological Changes In Specific Laminae Of The Olfactory Bulb Of Adult Zebrafish Following Peripheral Sensory Deafferentation, Travis L. Devlin

Masters Theses

Permanent removal of the olfactory organ in adult zebrafish has been shown to result in a significant reduction in the total volume of the ipsilateral olfactory bulb. The overall objective of the current project was to investigate the hypothesis that contact between the axons of the olfactory sensory neurons and the olfactory bulb is necessary for the maintenance of the normal post-synaptic organization of the olfactory bulb by quantifying the morphological changes that take place within specific laminae of the olfactory bulb following peripheral deafferentation. Complete, unilateral ablation of the olfactory organ resulted in permanent deafferentation of the ipsilateral olfactory …

Metabolic And Phenotypic Characterization Of Aerobic Pcb Degrading Bacteria Isolated From Kalamazoo River Sediments, Brenton K. Lehmkuhl

Masters Theses

The Kalamazoo River is contaminated with polychlorinated biphenyls (PCBs) which are neurotoxins and suspected carcinogens. The goal of this study was to isolate, identify, and metabolically characterize PCB degrading strains of aerobic bacteria. Biphenyl enrichments resulted in the isolation of putative PCB degrading strains from different locations along the river. Based on 16S rRNA gene analysis the isolated strains were identified as belonging to the genera of Achromobacter, Acidovorax, Cellulosimicrobium, Paenibacillus, Pseudomonas, and Rhodococcus. These strains were screened for their PCB degrading ability and congener specificity. All of the isolated strains degraded PCBs via the 2,3-dioxygenase pathway. The range …

Determining Environmental Drivers Of Fish Community Structure Along The Coast Of Maine, Adrian Jordaan

Electronic Theses and Dissertations

The work presented here was conceived to determine whether structure in marine communities could be related to multiple scaled environmental parameters, as seen in lake and stream systems. Four datasets collected from 2001 to 2005 were used. The datasets ranged from local scale tidepool and estuarine surveys, to more regional intertidal/subtidal surveys and conclude using a coast-wide trawl survey. Initially, a bootstrap program for running principal component analysis (PCA) was developed and tested for utility with additional information from Pearson correlation coefficients. The bootstrap-PC A program was capable of determining confidence limits for correlations amongst species. The results from analysis …

A Comparison Of The Amely Gene Sequence In Argali (Ovis Ammon) And Domestic (Ovis Aries) Sheep, Kimberly Elwood

Undergraduate Honors Capstone Projects

Amelogenin (AMEL) is a gene responsible for tooth bud development. It is located on the X-chromosome, thus called AMELX, in mammals. AMEL has been shown to be present in fish, amphibians, and reptiles, though the exact location on the chromosome has not been determined. Amelogenin-like gene (AMELY), an AMEL homolog encoded on the Y-chromosome in some mammals, including sheep, cattle, deer, bears, humans, and some primates, is shorter than the sequence on the X-chromosome. It is unknown whether AMELY is transcriptionally active, but it has been found to be useful for human sexing purposes in forensics, archaeology and prenatal diagnosis, …

Multiscale Habitat Associations Of Three Primary Burrowing Crayfish, Shane Welch

All Dissertations

The distribution and habitat associations of three primary burrowing crayfish species were examined at the landscape and patch scales. GIS based predictors were used to model the species occurrence across the study landscapes and vegetation structure data were used to model crayfish abundance within landscape patches. Distocambarus crockeri, a species endemic to the piedmont physiographic region of South Carolina was a terrestrial habitat specialist at broad because of its association with well drained ridge-top soils. Within these soils D. crockeri were dependent on open treeless habitats. The species habitat was consistent with early descriptions of the region and suggested that …

Development Of Methods For The Study Of Phosphoproteins, Zhaoyuan Chen

Theses and Dissertations

Characterization of phosphoproteins-including detection, identification of phosphoproteins and identification of phosphorylation sites-is mostly done with radiolabeling and proteomic techniques. Three main topics related to phosphoprotein characterization are included in this dissertation. First, large-scale characterization of the CHO (Chinese hamster ovary) cell phosphoproteome was done using two dimensional gel electrophoresis (2DE) separation, visualization of phosphoproteins by radiolabeling or a phosphoprotein specific dye, followed by MALDI-TOF identification. Because radiolabeling of phosphoproteins is very sensitive and straightforward to quantify, such analysis can give a clear picture of the relative phosphosphorylation of proteins present in a sample. But there are also limitations to this …

Phylogenetics Of North American Psoraleeae (Leguminosae): Rates And Dates In A Recent, Rapid Radiation, Ashley N. Egan

Theses and Dissertations

The scientific discipline of phylogenetics involves understanding the diversity of life in the context of history. Technological advances in molecular biology and computational power have created an exponential increase in the number and kind of phylogenetic studies, allowing exploration of all manner of questions concerning the evolutionary history of a group. This dissertation research is focused on phylogenetic theory and applying these methods to the plant tribe Psoraleeae (Leguminosae; Fabaceae) with an emphasis on North American (NAm) members. First, theory of phylogeny estimation is explored in a review chapter focusing on strengths and weaknesses of phylogenetic methodology. Second, methods are …

Consumer Perceptions Of Branded Beef Products, Leslie Erin Williams

Masters Theses

This study examined consumer perceptions of branded beef products. Research was conducted to determine what motivates consumers to purchase branded beef products. In addition, this study focused on consumer perceptions of quality, risk, added value, credibility and loyalty toward both branded beef products in general and branded beef products when compared to non-branded beef products.

A self-developed question guide was used as a guide for the focus group and the in-depth interviews. This study entailed one focus group with nine participants and nine one-on-one in-depth interviews.

The majority of participants in this study held a positive impression of branded beef …

Insights Into The Etheostoma Spectabile Species Complex: Incongruence Between Mitochondrial And Nuclear Gene Sequence Data, Christen M. Bossu

Masters Theses

Hybridization is recognized as an evolutionary process that can provide a significant source of genetic variation and whose genetic consequences have been investigated across a wide taxonomic range of plants and animals. Darters (Percidae: Etheostomatinae) are a clade with documented interspecific hybridization and many species with a recent evolutionary origin, yet most molecular phylogenetic analyses of darters to date have relied primarily on mitochondrial DNA (mtDNA) sequences. Inferring relationships within and between closely related species using a single locus gene tree is potentially confounded by introgression as well as retention of ancestral polymorphisms. This can lead to incongruence between the …

Horizontal Gene Transfer To Bacteria Of An Arabidopsis Thaliana Abc Transporter That Confers Kanamycin Resistance In Transgenic Plants, Kellie Parks Burris

Masters Theses

The use of antibiotic resistance markers is an important tool in the production and selection of transgenic plants. There have been increased concerns about the potential horizontal gene transfer (HGT) from transgenic plants to bacteria of medical and environmental importance. Until recently all antibiotic resistance genes used in transgenic studies have been bacterial in origin. An Arabidopsis thaliana ABC transporter, Atwbc19, was the first plant gene shown to confer kanamycin resistance when overexpressed in transgenic plants. The Atwbc19 gene was evaluated for its ability to transfer antibiotic resistance to Escherichia coli, which are found in the human gut and environment. …

Occurrence Of Antibiotic Resistance In Environmental And Amphibian E. Coli Isolates Associated With Cattle And Aquatic Environments, Robin Lynn Cissell

Masters Theses

The widespread use of antibiotics in human medicine and livestock production has been linked to an increase in resistant bacteria, which may carry transferable resistance factors, including integrons. Foodborne pathogens, such as Escherichia coli and salmonella, commonly reside in livestock, including cattle, and these pathogens may acquire resistance genes as a result of routine antibiotic use. As cattle are often located in close proximity to aquatic environments, they may disperse antibiotic resistant pathogens into such environments, which may lead to contamination of aquatic wildlife. We hypothesize that class 1 integrons and/or antibiotic resistant bacteria occur more frequently in environments with …

Supplementation Of Purified Fiber To Tall Fescue Grass Hay Diets, Howard Martin Blalock

Doctoral Dissertations

Experiments were conducted to define the degradation kinetics of purified fiber products compared to conventional feedstuffs. In situ analysis was conducted on soybean hulls, dried distillers grains, dried corn gluten feed, rice mill, wheat middlings, solka floc, oat fiber (200 and 300 series), corn bran, red and white wheat bran using nylon bags. In situ results determined oat fiber (300) and solka floc were most similar to soybean hulls and secondly to corn gluten feed. An oat fiber: solka floc mixture was formulated for subsequent experiments. The in vitro experiment consisted of alfalfa hay, soybean hulls, corn gluten feed, oat …