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Functional Regulation Of The Pituitary-Adrenal Axis In The Ovine Fetus, Feng Lu

Digitized Theses

The purpose of the present study was to elucidate the mechanisms regulating function of the ovine fetal pituitary-adrenal axis by hypothalamic, pituitary and adrenal factors, and by locally produced growth factors. Specifically, the effects of corticotropin releasing hormone (CRH), arginine vasopressin (AVP) and cortisol on CRH binding, levels of proopiomelanocortin (POMC) mRNA and adrenocorticotropin (ACTH) output from the fetal ovine anterior pituitary were evaluated in vitro. Further, expression of the insulin-like growth factor (IGF) genes and possible roles of IGFs in the ovine fetal pituitary-adrenal axis were examined.;Our studies provide the following results: (1) The number of CRH binding sites …

An Olfactory Input To The Dentate Gyrus: Electrophysiological, Behavioral, Pharmacological And Anatomical Studies, Vincent Robert Heale

Digitized Theses

Odors were presented under the nose of behaving rats and electrophysiological responses were recorded concurrently from the olfactory bulb and dentate gyrus. The results confirm previous work showing that some organic solvents elicit 15-30 Hz fast wave activity in both the olfactory bulb and dentate gyrus but further show that 2-propylthietane and trimethyl thiazoline (components of weasel and fox odors respectively) also elicit fast waves in the dentate gyrus while other strong odors do not. Noxious tactile stimulation in urethane anesthetized rats was found to produce an activation response in the dentate gyrus and olfactory bulb, similar to that seen …

Sand Accretion And Its Effects On The Distribution And Ecophysiology Of Dune Plants, John V. Perumal

Digitized Theses

The effects of sand accretion on the lacustrine sand dune vegetation of Lakes Huron and Erie were studied. The tolerance and response to burial in sand of several dune species, namely, Ammophila breviligulata, Adropogon scoparious, Agropyron psammophilum, Artemisia campestris, Calamovilfa longifolia, Cakile edentula, Cirsium pitcheri, Corispermum hyssopifolium, Elymus canadensis, Equisetum arvense, Euphorbia polygonifolia, Lithospermum caroliniense, Melilotus alba, Oenothera biennis, Panicum virgatum, Poa compressa, Strophostyles helvola, Tusilago farfara, Populas balsamifera and Xanthium strumarium were examined under controlled (greenhouse and growth chamber) and natural (field) conditions. This study clearly showed that the amount of sand deposition was variable in different microsites and …

Ecological Aspects Of Iron Acquisition In Synechococcus Sp (Cyanophyceae), Steven Wray Wilhelm

Digitized Theses

As primary producers, marine cyanobacteria regulate the biological and biogeochemical cycles of aquatic ecosystems and influence ocean-atmosphere gas exchange. The purposes of this project were to determine if a Synechococcus sp. was capable of utilizing a high-affinity iron transport system during periods of iron-limited growth and if physiological changes due to iron limitation could be identified. Resolution of these factors was achieved by maintaining the cyanobacterium Synechococcus sp. PCC 7002 in continuous culture chemostats over a range of iron availabilities.;Changes in physiology were detected over a range of iron concentrations. Reductions in the levels of photosynthetic pigments were accompanied by …

Whole-Cell Voltage Clamp Of Junctional Conductances In Insect Cell Pairs, J Dennis Churchill

Digitized Theses

Gap junction (GJ) channels are dynamic intercellular structures that open and close (gate) in response to cellular signals (e.g. voltage), and may be important in regulating cell-to-cell communication in insect development. This thesis presents one of the first biophysical characterizations of GJ channels in insect cell pairs. Double whole-cell voltage-clamp techniques were employed on epidermal cells from the larval flour beetle, Tenebrio molitor, to measure the conductances and substate gating properties of individual GJ channels and the effects of voltage and ATP on gating. In addition, these techniques were used to examine the early events of rapid GJ formation between …

Gap Junction Gene Expression In The Developing Nervous System, Daniel J. Belliveau

Digitized Theses

Gap junctions provide for the transfer of low molecular weight molecules and ions between cytoplasms of adjacent cells. Connexins exist as a multigene family with one or more members found in almost all adult tissues. In the central nervous system, gap junctions have been detected in a variety of cell types including neurons, astrocytes and oligodendrocytes. Gap junctions have been detected in the developing brain in a spacial and temporal pattern. This study examines gap junction expression and cellular specificity during development of the rodent central nervous system. To investigate the role of gap junctions during development, a model of …

Structural Aspects Of The Mu Transpososome, Brigitte Denise Lavoie

Digitized Theses

Transpososomes are higher order nucleoprotein structures which mediate the Mu in vitro strand transfer reaction. The product of the strand cleavage reaction, the Type 1 transpososome, has been further characterized. This complex constrains the nicked ends of Mu through a myriad of protein-protein and protein-DNA interactions and precedes the strand transfer step. At least two proteins are required for the efficient formation of this intermediate, Mu A and E. coli HU. Immunoelectron microscopic studies have revealed that both A and HU localize to greater than 90% of the complexes; however, a tetrameric unit of Mu A, as seen by protein …

Rates Of Energy Consumption And Acquisition By Lecithotrophic Larvae Of Bugula Neritina (Bryozoa: Cheilostomata), William Jaeckle

Scholarship

Lecithotrophic larvae of the cheilostome bryozoan, Bugula neritina (L.), lose metamorphic competence 12 to 24 h after release from the maternal zooid. The high respiration rate of newly released larvae (mean=306.3 pmol O₂ larva^-1 h^-1, range= 149.3 to 466.6, n=18 trials, 22.5 °C) from adults collected at Link Port, Fort Pierce, Florida during the winter/spring of 1990-1991 reflects their active swimming behavior. The average energy con¬tent per larva was 15.24 mJ (range: 13.35 to 20.17 mJ ind^-1, n=5 groups). If all cells have an identical energy content and metabolic rate, then 2 and 20% …

G94-1208 Managing The Alfalfa Weevil, Stephen D. Danielson, Thomas E. Hunt, Keith J. Jarvi

University of Nebraska-Lincoln Extension: Historical Materials

The identification and life cycle of the alfalfa weevil are discussed along with scouting techniques, economic thresholds, and other integrated pest management tactics.

The alfalfa weevil is the primary insect pest of alfalfa in Nebraska. Management is essential to reduce crop losses, particularly during years when weevil infestation is high. Because there also are years when weevil damage is economically unimportant, it is necessary for growers to become familiar with sampling procedures, management guidelines, and control recommendations so control techniques are not used unnecessarily.

Genetic Variation Of The Lyme Disease Spirochete, Borrelia Burgdorferi, And Its Tick Vector, Ixodes Dammini, Diane Amy Caporale

Doctoral Dissertations

The causative agent of Lyme disease, Borrelia burgdorferi, is a spirochete transmitted among vertebrate hosts by Ixodid ticks. The outer surface of bacteria plays an important role in the ability to establish an infection in its host. The possibility that positive selection acts to accelerate the evolution of the outer surface protein genes was examined by comparing the DNA sequences of the OspA/B operon of B. burgdorferi isolates from North America and abroad. The Mean d$\rm\sb s$ values were two-fold higher than mean d$\rm\sb N$ values. Central regions of the OspB gene show an excess of silent mutations, while end …

The Role Of Opsonin-Independent Bacterial Adherence In The Pathogenesis Of Legionnaires' Disease, Frank Clinton Gibson

Doctoral Dissertations

Legionella pneumophila is a facultative intracellular bacterial pathogen which initiates infection of the human host by adhering to macrophages in the alveoli of the lung following which internalization and intracellular multiplication occurs. In this study a novel mechanism of opsonin-independent attachment for this organism to host cells was identified. L. pneumophila serogroup 1, strain Nottingham N7, and U-937 cells as well as primary guinea pig alveolar macrophages were used to study this adherence phenomenon.

A variety of assay methods were used to evaluate the nature of this binding event: transmission electron microscopy and scanning electron microscopy were used to visualize …

Adherence Of Salmonella Typhimurium To Murine Peritoneal Macrophages, Saif Nasser Al-Bahry

Doctoral Dissertations

Salmonella species are responsible for wide spread disease in both humans, and animals and macrophages (MO play a central role in host defenses against disease. Recent evidence has shown that MO bear surface receptors involved in direct microbial recognition. Using the mouse model and a virulent strain of S. typhimurium, we have attempted to determine the means by which peritoneal MO recognize this pathogen in the absence of serum factors. Bacterial adherence was monitored by direct microscopic visualization and by flow cytometry. Two strains of S. typhimurium strains 1826 and ATCC 14028 were used in this model. Adherence was much …

The Detection Of Enteric Viruses By Nylon-Based And In Situ Nonisotopic Probe Assays And Their Use In Treated And Untreated Waters, Norman James Moore

Doctoral Dissertations

Potable water is a primary need of humankind. In the interest of public health, the water should be free of infectious agents, such as bacteria, intestinal parasites, and viruses. The current method for assaying water for viruses is cell culture, which is expensive, labor intensive, and time consuming. Nucleic acid probes offer an alternative method which is less costly, more rapid, and requires less training and experience. Consequently, this study provides alternatives to viral monitoring of water sources.

Three nonradioactive nucleic acid probe assays were developed and evaluated by colormetric and chemiluminescent signals. A biotin-tailed probe was able to detect …

Assessing The Effects Of Nitrogen Availability On Fine Root Turnover And Tissue Chemistry In Forest Ecosystems, Joseph Jefferson Hendricks

Doctoral Dissertations

The patterns and controls of fine root (i.e., non-woody roots generally $\le$ 0.5 mm and 1 mm in diameter for deciduous and coniferous species, respectively) turnover and tissue chemistry were assessed along artificial and natural nitrogen availability gradients within and among forest ecosystems. Fine root turnover rate and chemical composition were generally strongly correlated with nitrate availability indices. A pilot study using a new $\sp{15}$N tracer technique suggested that turnover rates increased with nitrate availability in a red pine (Pinus resinosa Ait.) stand and indicated that this turnover assessment technique may avoid the major limitations which hinder existing methods. Assessments …

Effects Of 17 Beta-Estradiol On Cellular And Molecular Atherogenic Events In Animal Models, Glenn Thomas Shwaery

Doctoral Dissertations

Estrogens may protect against coronary artery disease (CAD) as women have less CAD than age-matched men, and postmenopausal women on estrogen have less CAD than those without replacement therapy. To elucidate potential benefits of 17 beta-estradiol on atherogenesis, female swine and hamsters were treated to yield three groups: (1) ovariectomized (ovex), (2) ovariectomized with estradiol replacement (ovex + estradiol), and (3) sexually intact. Postoperatively, animals were switched from a low fat to a high fat diet for measurement of acute estradiol effects in swine and chronic effects in hamsters. Swine monocyte and platelet adhesion to porcine aortic endothelial cells (PAEC) …

Wind-Driven Observation And Modelling In The Strait Of Gibraltar, Benabdeljelil Abdelkader

Doctoral Dissertations

Meteorological forcing has been found to be responsible for 65% of the subtidal current variance through Gibraltar Strait. However this value does not discriminate between atmospheric pressure and wind. Conditional coherences applied to a 2-input/single output system are computed to distribute the total variance of current data from the Gibraltar Experiment into wind-only, pressure-only, noise and shared forcings. Evidence is presented which shows that, within the subtidal range, wind and atmospheric pressure force the flow equally.

This study focuses on understanding the dynamics of the wind-driven circulation in a 2-layer channel. A channel jet model proves to be very useful …

Measurements Of Foliar Chemistry Using Laboratory And Airborne High Spectral Resolution Visible And Infrared Data, Mary Elizabeth Martin

Doctoral Dissertations

Remote sensing of foliar chemistry has been recognized as an important element in producing large scale, spatially explicit estimates of forest ecosystem function. Visible and near infrared reflectance measurements of forest foliage, at both the leaf and canopy scales, were studied in an effort to relate spectral data to foliar chemical composition. At the scale of the individual leaf, near infrared spectra and chemical data were collected from 211 fresh leaf samples, including 17 different hardwood and conifer species. Reflectance data at selected near infrared bands was closely related to the nitrogen, lignin, and cellulose concentration of these leaf samples, …

A Study Of Floral Development In Asparagus Officinalis L, Heather G. Miller

Doctoral Dissertations

Asparagus officinalis L. is typically classified as a dioecious species. However, in all-male hybrid cultivars, a percentage of individuals within a population exhibit a persistent perfect flowering (hermaphrodite) phenotype. Floral meristem development was divided into eight distinct stages of development and those developmental stages were compared in UC157 male, UC157 female, and 32/83 hermaphrodite individuals using scanning electron microscopy (SEM). In females, anthers abort between stages five and six. In males, style development is halted at stage eight. Hermaphrodites exhibit normal development of both anthers and styles. Within the 32/83 cultivar, the number of developing carpels can vary and some …

Steady-State Natural Fluorescence, Arnold Francis Theisen

Doctoral Dissertations

This study employed a manifold analytical approach to the application of multiple excitation and emission wavelengths of steady-state natural fluorescence for the detection of stressed and damaged vegetation. This investigator has attempted to answer questions put forth in terms of the following null hypothesis: Natural fluorescence emission, measured in the steady-state from living, attached or freshly excised needles of eastern white pine (Pinus strobus L.) or leaves of common beans (Phaseolus vulgaris L.), cannot be used in the form of complete spectra or in ratios of discrete wavelengths as indicators of stress from abiotic sources such as ozone or cadmium. …

The Complete Nucleotide Sequence Of The Sea Lamprey (Petromyzon Marinus) Mitochondrial Genome: Implications For The Evolution Of Animal Mitochondrial Genome Structure And Rates Of Evolution In Vertebrates, Woo-Jai Lee

Doctoral Dissertations

The complete nucleotide sequence of the sea lamprey (Petromyzon marinus) mitochondrial genome has been determined using purified, intact mtDNA. The lamprey mitochondrial genome is 16,201 bp in length, and contains genes for 13 proteins, 2 rRNAs, 22 tRNAs and 2 major non-coding regions. The genome displays several minor rearrangements but is basically colinear with other vertebrate genomes.

The sequence suggests that the vertebrate mitochondrial genomic organization was established at an early stage of vertebrate evolution. Comparisons with teleost and mammalian mitochondrial control regions demonstrate that some conserved sequence blocks have arisen recently. The overall base composition of the genome is …

The Roles Of Scale And Methodology In Determining The Apparent Effects Of Biological Invasions, Jody Berman

Doctoral Dissertations

The general aims of this research were to explore conflicting views of community structure and species introductions. In the former, I was interested in evaluating the relative importance of species interactions in determining their relative distribution and abundance. In the latter, my primary goal was to examine whether or not reported competitive dominance was a good predictor of either invasion mechanism or effect. As this research developed, an additional focus became the role of scale and methodology in determining how researchers perceive the effects of biological invasions.

Preliminary work (Chapter 1) took a broad approach, examining three species of sessile …

Genetic Engineering Of The Polyamine Biosynthetic Pathway And Somatic Embryogenesis In Carrot (Daucus Carota L), Dhundy Raj Bastola

Doctoral Dissertations

Ornithine decarboxylase (ODC), arginine decarboxylase (ADC), and S-adenosylmethionine decarboxylase (SAMDC) are three of the key regulatory enzymes involved in the biosynthesis of polyamines (putrescine, spermidine and spermine). To modulate the biosynthesis of putrescine, carrot (Daucus carota L.) cells were transformed with Agrobacterium tumefaciens strains containing 3$\sp\prime$-truncated mouse ornithine decarboxylase (ODC) cDNA under the control of a CaMV 35S promoter. Neomycin phosphotransferase gene linked with nopaline synthase promoter was used to select transformed cell lines on kanamycin. While the non-transformed cells contained no ODC, high levels of ODC activity were observed in the transformed cells. A significant increase in the cellular …

Penetration Of The Pz-Peptide Through The Various Membranes Of The Gastrointestinal Tract, Jyun "Jay" Nakamura

Whittier Scholars Program

The use of the oral drugs dates back to the beginning of recorded time. Since the modern era, doctors and researchers have found the various physiological pathways by which they operate and function. Within the past fifty years, this research has proceeded to the cellular and molecular levels. Researchers have found that the drugs target specific components of the infected cells. These drugs interact by binding to three different types of target molecules. The chemicals target receptors found on extracellular proteins, macromolecules like enzymes, transport molecules, nucleic acids, and membrane lipids. With these new findings, new techniques and equipment have …

A Functional Dissection Of The Yeast Ccr4 Protein And Identification Of Associated Factors, Michael Preston Draper

Doctoral Dissertations

The yeast CCR4 protein is required for the expression of a number of genes involved in non-fermentative growth, including glucose repressible ADH2, and is the only known suppressor of mutations in the SPT6 and SPT10 genes, two genes which are believed to be involved in chromatin maintenance. It is shown here that CCR4 is able to activate transcription when fused to a heterologous DNA binding domain. The transcriptional activation ability of CCR4, in contrast to many other activators, was glucose regulated. Two activation domains were identified, one of which was glucose responsive and encompassed a glutamine-proline rich region similar to …

Elevation Of The Hatching Envelope In Penaeidea Shrimp: Morphology And Assembly., Patricia Stoops Glas

LSU Historical Dissertations and Theses

The appearance of extracellular coats around "eggs" are associated with activation of the oocytes. This coat, termed fertilization envelope (sea urchins), chorion (fish), zona pellucida (mammals), capsule (crab) or hatching envelope (HE) (shrimp) serves as a polyspermy block (Wasserman, 1982) or microenvironment protecting the egg from bacteria or other hostile elements (Kudo and Inoue, 1989; Kudo and Teshima, 1991; Kudo, 1992; Epel, 1993). HE assembly is described for penaeoid shrimp (Lynn, et al., 1991) and is, in contrast to many systems, a fertilization independent event. However, the mechanisms of assembly appear similar to extracellular coat formation in other animal systems …

The Role Of Infaunal And Epifaunal Suspension Feeding Macrofauna On Rates Of Benthic-Pelagic Coupling In A Southeastern Estuary., Christine Miller-Way

LSU Historical Dissertations and Theses

This research investigated the effects of two suspension feeding bivalves, the infaunal Rangia cuneata, and the epifaunal Crassostrea virginica, on benthic-pelagic coupling in Fourleague Bay, LA, a river-dominated estuary. A continuous-flow microcosm system was developed to overcome recognized limitations of batch methodology and to facilitate manipulations designed to investigate the ecological role of benthic macrofauna. Experiments comparing traditional batch methodology to continuous-flow methodology indicated that rates of benthic processes were consistently greater when measured using continuous-flow methodology. Examinations of concentrations indicated that differences were due to concentration gradients which departed from ambient over time in the batch cores. Over an …

Pharmacodynamics Of Non-Steroidal Anti-Inflammatory Agents In Acute Inflammation And Chronic Pain In The Horse., Jane Granville Owens

LSU Historical Dissertations and Theses

The analgesic and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs (NSAIDs) ketoprofen (2.2 and 3.63 mg/kg) and phenylbutazone (4.4 mg/kg) were compared in equine models of acute synovitis and chronic hoof pain. The eicosanoids, prostaglandin E$\sb2$ (PGE$\sb2$) and leukotriene B$\sb4$ (LTB$\sb4$), increased dramatically in synovial fluid after carrageenan-induced synovitis of the intercarpal joint. PGE$\sb2$ concentrations in untreated horses peaked at 9 hours while LTB$\sb4$ concentrations peaked in all horses at 3 hours. Synovial fluid concentrations of both eicosanoids returned to near baseline by 48 hours. Lameness, joint temperature, and synovial fluid volume, protein and nucleated cells increased at 3 to …

Promoter Analysis Of A Rice Seed Storage Protein Glutelin Gene And Expression Of Bean 7s Seed Storage Protein Beta-Phaseolin In Transgenic Rice Plants., Zhenwei Zheng

LSU Historical Dissertations and Theses

It was demonstrated, using a homologous transgenic rice system, $5\sp\prime$ distal and proximal cis-acting transcriptional regulatory elements were required for developmental control of a rice seed storage protein glutelin (Gt1) gene. The functional importance of proximal elements in the context of the 1.8 kb promoter was demonstrated by single substitution mutations in the TATA box ($-$28/$-$23), AACA motif ($-$73/$-$61), and protein-binding Boxes I ($-$103/$-$86), II ($-$124/$-$110), III ($-$175/$-$158), and IV ($-$200/$-$217). A simultaneous mutation of five protein-binding sites ($-$410/$-$86) essentially eliminated the activity of the 1.8 kb promoter. To understand the function of the $5\sp\prime$ distal cis-acting upstream sequence, eighteen …

Transcriptional Cis-Regulatory Elements And Trans-Factors Of A Gene For The Seed Storage Protein Beta-Phaseolin From Common Bean (Phaseolus Vulgaris)., Yasushi Kawagoe

LSU Historical Dissertations and Theses

In many dicotyledons, the nutrient reserves are stored in the cotyledons. Phaseolin, 7S globulin, is the major seed protein from common bean Phaseolus vulgaris. In vitro transcription assays and gene transfer studies indicate that phaseolin gene expression is regulated primarily at the transcriptional level. In this dissertation, I studied cis- and trans-acting factors that may play a role in the transcriptional regulation of the $\beta$-phaseolin gene. Gel mobility shift and exonuclease III protection assays identified four distinct DNA binding proteins, CAN, AG-1, CA-1, and TATA-box binding protein. Three CANNTG motifs, CACGTG ($-$248/$-$243), CACCTG ($-$163/$-$158), and CATATG ($-$100/$-$95), were found to …

Electrophysiological Responses Of Olfactory Receptor And Bulb Neurons To Stimulus Mixtures And To Their Individual Components In The Channel Catfish, Ictalurus Punctatus., Jiesheng Kang

LSU Historical Dissertations and Theses

Both electro-olfactogram and integrated multiunit receptor responses of populations of olfactory receptor neurons (ORNs) clearly showed that responses to complex mixtures were predictable. Results demonstrated that receptor sites for basic and acidic amino acids, respectively, are independent from those for neutral amino acids and multiple receptor site types with highly overlapping specificities exist for amino acids within each group. Results also confirmed that one mechanism for synergism is the simultaneous activation of relatively independent receptor sites by the components in a mixture, and there was no evidence of mixture suppression. Single ORNs recorded in vivo responded to stimuli with either …