Digital Commons Network^™

Characterization Of Invariant Membrane Proteins Of Trypanosoma (Duttonella) Vivax, Barbara Anne Burleigh

Digitized Theses

Monoclonal antibodies (mAbs), raised against whole, fixed, uncoated, culture forms of Trypanosoma (Duttonella) vivax, were used to identify two invariant membrane proteins of this protozoan parasite. Since non-variant membrane proteins of the cell surface, flagellar pocket and endocytic pathway are potential targets for the control of trypanosomiasis of livestock by immunization, the identification and characterization of invariant membrane proteins is a necessary preliminary step.;A 65 kDA invariant membrane glycoprotein (gp65), identified using mAb 4E1, was the main focus of this study. Immunolocalization studies using the monoclonal antibody (mAb 4E1) for immunofluorescence staining and immunoelectron microscopy, demonstrated that the 65 kDa …

Submicron Correlations Of Receptor-Positions On Cell Surfaces, Paul St-Pierre

Digitized Theses

Scanning fluorescence correlation spectroscopy (S-FOS) is introduced as a technique to measure the distribution of receptors on cell surfaces. The receptors are made observable by the binding of a specific ligand that is fluorescently labeled. This technique is based on fluctuation analysis through direct calculation of correlation functions. It uses a confocal microscope configuration to obtain fluorescence records as a function of laser beam position on the surface of cells. The fluorescence records present fluctuations that have a characteristic persistence length equal to the laser beam width. The calculated correlation function decays as the laser beam intensity profile which is …

Brainstem Control Of Three-Dimensional Eye Movements, J Douglas Crawford

Digitized Theses

This thesis examines the neural mechanisms that generate torsional and vertical eye movements, and how they handle the kinematics of three-dimensional rotations. Three-dimensional eye rotations were recorded in alert monkeys, and the midbrain was studied using single unit recording, electrical microstimulation, and pharmacological inactivation.;The direction of VOR slow phases was usually opposite to that of head rotation, as required for optimal visual stabilization. However, direction errors sometimes occurred because of low gain about a head-fixed torsional axis. This axis was orthogonal to Listing's plane of saccadic eye positions, which suggests that saccades and the VOR share the same coordinate system. …

Ventilatory Response To Carbon Dioxide Stimuli In Aged Humans, Marc Jean Poulin

Digitized Theses

This thesis examined age-related changes in the ventilatory response to exercise and in the ventilatory response to inhaled carbon dioxide (CO{dollar}\sb2{dollar}) at rest. Specifically, the purposes were to: (1) examine the ventilatory response to CO{dollar}\sb2{dollar} production (VCO{dollar}\sb2{dollar}) during graded exercise below the ventilation threshold (T{dollar}\sb{lcub}\rm \.VE{rcub}{dollar}) in men and women aged 55 to 86 yrs, (2) determine the ventilatory response to CO{dollar}\sb2{dollar} at rest and evaluate the CO{dollar}\sb2{dollar} sensitivity of the central and peripheral chemoreceptors in young (YS, n = 7, 28.3 yrs) and old (OS, n = 11, 76.1 yrs) humans, and (3) determine the temporal parameters of the …

Host And Viral Determinants Influencing The Pathogenesis Of Coronavirus-Induced Neurological Disease In Rodents, John M. Pasick

Digitized Theses

Host and viral determinants influencing the outcome of coronavirus JHM infections of the CNS of rodents were investigated using intact animals and primary neural cell cultures. Two problems pertinent to the process of pathogenesis were addressed. The first was concerned with elucidating host factors responsible for controlling the age dependent nature for induction of the demyelinating form of disease in suckling rats. In the second, the basis of the relative resistance exhibited by inbred SJL/J mice to JHMV was examined in relation to both host and viral determinants.;Using primary, dissociated neural cultures from perinatal rats, several interesting aspects of host …

The Relationship Between Wetland Productivity And The Distribution Of Breeding Mallards, Black Ducks, And Their Broods: Historical And Spatial Analysis, Michael Todd Merendino

Digitized Theses

During the last 50 years mallards have increased dramatically in southern Ontario and have completely replaced black ducks in many areas. In northern Ontario, black duck densities appear stable at present, however, mallard densities now exceed 60 pairs/100 km{dollar}\sp2{dollar} in many areas. I examined historical and spatial distributions of mallards and black ducks in Ontario in relation to water chemistry and physical habitat characteristics. My objectives were to determine (1) if mallards invaded the most fertile wetlands, and (2) if mallards replaced black ducks on the most productive wetlands.;I used Canadian Wildlife Service survey data (1971-87) to define 7 wetland …

Connexin Gene Expression And The Control Of Gap Junction Assembly In Preimplantation Development, Gunnar Valdimarsson

Digitized Theses

Gap junctional communication in preimplantation mouse embryos was explored by investigating: (1) the expression pattern of the connexin (Cx: gap junction protein) multigene family in maturing mouse oocytes and preimplantation embryos; (2) the relative role of Cx43 in gap junctional communication in embryos; and (3) the control of the acquisition of gap junctional coupling.;Both Cx43 and Cx32 transcripts were detected in maturing oocytes but these transcripts declined to undetectable levels shortly after ovulation. Cx43 transcripts were detected again at the 4-cell stage and accumulated steadily thereafter to reach a maximum in blastocysts. Cx26 and Cx46 transcripts could not be detected …

The Reproductive Ecology Of Convict Cichlids In Costa Rica, Brian Douglas Wisenden

Digitized Theses

Convict cichlids (Cichlasoma nigrofasciatum) form monogamous pair bonds and have cooperative biparental care of their eggs, larvae and fry for up to six weeks. This fish is widely used in laboratory studies as a model of biparental care. However, very little is known of its habits in its natural habitat. I studied four natural populations of convict cichlids, in 'pool' and 'stream' habitat, in Costa Rica during the long dry season, December to June in 1990 and 1991. The number of pairs guarding broods increased from December to a peak in mid-March, then rapidly declined. Twenty-eight percent of 175 males …

Connexin Trafficking And The Control Of Gap Junction Assembly In The Mouse Preimplantation Embryo, Sousa Paul De

Digitized Theses

Gap junction assembly in the preimplantation mouse embryo is a temporally regulated event, beginning a few hours after the third cleavage during the morphogenetic event known as compaction. The purpose of the present study was to determine which connexins contribute to gap junctions in the preimplantation mouse embryo and how their assembly into gap junctions at compaction is regulated. Using antibodies raised against different synthetic C-terminal peptides of connexin43 (Cx43), this protein was shown to assemble into gap junction-like plaques beginning with compaction. Prior to this time no Cx43 can be detected in the plasma membrane. Cell fractionation and reverse …

Regulation Of Choline Acetyltransferase In Rat Hippocampal Synaptosomes, Bonnie Marie Schmidt

Digitized Theses

Choline acetyltransferase (ChAT; EC 2.3.1.6) catalyses the biosynthesis of acetylcholine (ACh) from choline and acetylCoenzyme A in cholinergic neurons. Within nerve terminals, this enzyme exists in both cytosolic and membrane-bound forms, although the role of the latter fraction is not clear. ChAT is clearly subject to long-term regulation (over periods of hours to days), likely through alterations in protein synthesis, however very little is known about short-term regulation (seconds to minutes). Therefore, the goals of this study were to determine the mechanisms of short-term regulation of ChAT activity and to elucidate the physiological role of membrane-bound ChAT in ACh biosynthesis.;Using …

Substrate Adhesion And Gap Junction Formation By Insect Hemocytes In Vitro, Sheppy Israel Coodin

Digitized Theses

Circulating insect hemocytes become adherent to foreign surfaces and to one another during immune and wound healing responses. Hemocytes form various types of intercellular junctions, including gap junctions, as they encapsulate large foreign objects in the hemocoel. This study focuses on two aspects of hemocyte behaviour in vitro: hemocyte/substrate adhesion and gap junction formation.;Cockroach (Periplaneta americana) hemocytes resuspendad in medium containing purified lipophorin, either in the presence or absence of Ca{dollar}\sp{lcub}2+{rcub},{dollar} remained non-adherent to glass coverslips and retained a discoid morphology in vitro for at least 30 minutes. In contrast, hemocytes incubated either with or without Ca{dollar}\sp{lcub}2+{rcub}{dollar} for 30 minutes …

Isolation And Characterization Of A Genetic Locus Involved In Growth And Pathogenicity On Tomato Plants By Pseudomonas Syringae Pv Tomato, Dennis Paul Jackson

Digitized Theses

Pseudomonas syringae pv. tomato is the causal agent of bacterial speck on tomato. An essential feature of this organism, in the pathogenic process, is its ability to enter the intercellular spaces of its host and use the available plant substrates for growth. Tomato leaves contain quantities of carbon energy in the form of carboxylates. A Tn5 mutant, DC3481, cannot utilize carboxylates as a source of carbon energy for growth (CA{dollar}\sp-{dollar}) and is nonpathogenic (Path{dollar}\sp-{dollar}) on tomato. The focus of this thesis was to utilize DC3481 to isolate and characterize P. syringae pv. tomato DNA sequences involved with growth and pathogenicity …

Age-Related Changes In The Numbers And Physiological Properties Of Human Motor Units, Timothy John Doherty

Digitized Theses

Age-related changes in the numbers and physiological properties of human motor units (MUs) were examined in four studies.;In the first study, spike-triggered averaging was used to estimate the numbers of MUs in the biceps brachii and brachialis muscles. The maximum isometric twitch contraction (MTC) and maximum voluntary contraction (MVC) of the elbow flexors were also measured. In older subjects, the estimated numbers of MUs were significantly reduced (47%) whereas, average surface-detected motor unit action potential (S-MUAP) sizes were significantly larger (23%). Significant but less marked age-associated reductions were found for the MTC (33%) and MVC (33%).;In the second study Multiple …

Neuroanatomical And Neurochemical Organization Of Compartments In The Basal Ganglia Of The Rat, Nagalingam Rajakumar

Digitized Theses

The structural and neurochemical organization of the basal ganglia of the rat was investigated with highly sensitive modern anterograde and retrograde tracing methods in combination with immunocytochemical identification of intrinsic neuronal substances with the optical and laser-confocal microscope to address the fundamental organization of these centers as an integrated system.;Based on the present results and other evidence, a functional model of the basal ganglia is proposed: The corticostriatal inputs activate a large population of striatal neurons. Among these, appropriate neurons are 'selected' within each functional domain by the dopaminergic, cholinergic, and GABAergic recurrent collateral inputs. The same corticostriatal input simultaneously …

Ecological Aspects Of Regeneration From Root Fragments In Two Physalis Species, Adan Elmi Abdullahi

Digitized Theses

Clammy (Physalis heterophylla Nees.) and smooth (P. virginiana Mill. var. subglabrata (Mackenz. and Bush) Waterfall) ground-cherry are perennial herbs that grow in cultivated fields, roadsides, pastures, and open woodlands. It was postulated that both species are capable of surviving in highly disturbed habitats because of their extensive root systems and their capacity to regenerate from root fragments. Field and greenhouse experiments were conducted in 1991 and 1992 to investigate the effects of root fragment size, depth of root burial, root fragment orientation at planting, plant growth stage at the time of root fragmentation, and origin of the root fragments, on …

The Lake Erie Program: Monitoring Fish Stock Changes Over Years, Jacques Lemaire

Digitized Theses

The Lake Erie Fisheries Program of the Ontario Ministry of Natural Resources used a stratified sampling design with partial replacement of catch stations from 1987 to 1990 to monitor the fish community. Estimation methodology associated with partial replacement sampling design based on double sampling regression estimates was not suitable for the small sample sizes encountered and for multivariate descriptive study.;An unbiased estimation methodology for detecting changes and for descriptive study has been developed for two or more sampling occasions in either a simple or a stratified statistical population. The methodology for two occasions links well known cases in statistical inference …

Cell Surface Phosphorylation And Myogenesis In L6 Rat Myoblasts, Xiaoyong Chen

Digitized Theses

Cell surface components are important for myogenic differentiation. Studies with subconfluent day-2 cultures of rat myoblasts revealed that a cell surface 112 kDa protein was phosphorylated by a Ca{dollar}\sp{lcub}++{rcub}{dollar}, F{dollar}\sp-{dollar}, and Mg{dollar}\sp{lcub}++{rcub}{dollar}-dependent ectoprotein kinase (ecto-PK), and that adequate ATP was present on the cell surface for the efficient functioning of this ecto-PK. The following evidence suggests that both the 112 kDa protein and the ecto-PK may play important role(s) in the initiation of myogenesis. (i) The highest phosphorylation activity was observed in subconfluent culture, i.e. before the onset of myogenesis. (ii) Treatment of cells with myogenesis inhibitors also resulted in …

Human Cerebral Microvascular Endothelial Involvement In Neovascularization Of Malignant Glial Tumors, Penelope Catherine Costello

Digitized Theses

Human malignant glial tumors are highly vascular compared to normal brain. Increased tumor vessel permeability contributes to patient morbidity and mortality. An in vitro model of neoplastic and non-neoplastic brain microvasculature was established to address questions related to human glial tumor-associated angiogenesis. Investigation of tumor and non-tumor microvessel endothelial growth characteristics and ultrastructural properties related to permeability revealed detectable alterations as a result of tumor modulation. Endothelium derived from malignant glial tumor microvessels displayed decreased longevity and intercellular contact, and increased vesicle density in vitro compared to non-tumor microvessel endothelium. Human cerebral microvascular endothelium maintains properties noted in vivo, validating …

Philopatry And Dispersal By The Deer Mouse (Peromyscus Maniculatus Borealis) In The Kananaskis Valley, Alberta, Taye Teferi

Digitized Theses

I used mark-recapture techniques to study the dispersal and settlement pattern of Peromyscus maniculatus in a seasonal environment. In this study, spanning three breeding seasons (1989-1991), I had three objectives.;First, I tested the hypothesis that philopatry was female-biased. Natural populations of P. maniculatus were monitored on two live-trapping grids. Resident mice born to known dams had their dispersal distance estimated based on the distance between the geometric centres of their natal home ranges and those of their own. Mice with home ranges overlapping or abutting their natal range were considered philopatric; those whose ranges did not overlap or about their …

A Study Of The Growth Of Daughter Cladodes In The Species Of Cactus Opunita Ficus-Indica, Lin Moore

Whittier Scholars Program

Opunita ficus-indica is an example of a Prickly Pear cactus. Indigenous to Mexico, it is cultivated world wide for its edible flesh and fruit. It’s water use efficiency is high. The plant establishes where there is deep soil and a little subirrigation, such as washes in valleys or at the mouths of small canyons. The fleshy stem pads are called cladodes. The basal cladode is the lowermost cladode, and daughter cladodes grow from it. Daughter cladodes grow in orientations that maximize PPFD. Favorably oriented cladodes produce more daughter cladodes than those that are orientated unfavorably. Since O. ficus- indica is …

Insertion Sequence Elements In Yersinia: Nucleotide Sequence Of Is100 Of Yersinia Pestis, Stephen Dale Torosian

Doctoral Dissertations

The World Health Organization classified (Williams, 1983) Y. pestis as Y. pseudotuberculosis subsp. pestis on the basis of DNA homology, yet the two organisms cause markedly different disease. Portnoy and Falkow (1981) reported IS100 to influence the virulence of Y. pestis. IS100 was shown to be found in Y. pestis but not Y. pseudotuberculosis.

IS100 from Y. pestis was sequenced and shown by sequence analysis to fulfill the requirements of being an IS element. pIS1C, an 821 bp fragment of IS100 was transferred to Y. pseudotuberculosis Trp-Ca-, resulting in the ability of the cells to ferment rhamnose and delayed production …

Strawberry Malformation And The Tarnished Plant Bug, David Thomas Handley

Doctoral Dissertations

Experiments were designed to study the malformation of strawberries, Fragaria x ananassa (Duchesne) caused by the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois). In greenhouse experiments, duration of blossom exposure to tarnished plant bug affected the type of malformation observed. Exposure at anthesis for 48 hours was most likely to cause apical seediness, the malformation associated with tarnished plant bug. The number of nonviable achenes per fruit increased with longer feeding durations. Malformation was also affected by blossom stage. Prebloom feeding caused blossom death. Feeding at petal fall or achene separation resulted in malformations, including apical seediness. Feeding at …

Light Detection System In Higher Plant Chloroplasts: Pigment Mediated Or Overall Photon Flux Density Related, Soumitra Ghoshroy

Doctoral Dissertations

Plants adapt to short term changes in irradiance and quality of the light environment by modulating the structure of the thylakoid membranes to make the best use of the available light energy. Shade-acclimated chloroplasts develop more thylakoid surface area as compared to those growing in full sunlight. Conversion of sun-type chloroplasts to shade-types and vice versa on the basis of total thylakoid membrane surface area can occur quickly. However, the response mechanism of chloroplasts to changes in light levels is yet to be understood. This short term light detection mechanism may be mediated by a pigment system other than photosynthetic …

Regulation Of The Yeast Transcriptional Activator Adr1, W James Cook

Doctoral Dissertations

Glucose repression of the ADH2 gene from Saccharomyces cerevisiae is mediated by the abundance and activity of the transcriptional activator ADR1. The focus of this dissertation is to characterize the mechanisms by which glucose controls the ability of ADR1 to activate ADH2 transcription.

Glucose results in a two-fold decrease in the steady state levels of ADR1 mRNA. This glucose-dependent reduction in steady state ADR1 mRNA was shown to be due to an increased rate of ADR1 mRNA degradation. The unusually long, 510 nucleotide 5$\sp\prime$ untranslated region of the ADR1 mRNA appeared to mediate this glucose-dependent ADR1 mRNA decay.

To better …

A Multi-Scale Analysis Of The Population Ecology Of A Temperate Reef Fish, Phillip S. Levin

Doctoral Dissertations

Using field experiments and descriptive analyses this study investigated the significance of larval settlement and post-settlement processes to populations of cunner, Tautogolabrus adspersus. At small spatial scales there was no relationship between the density of new recruits and the percent cover of kelp, foliose algae and branching algae. Crustaceans and mussels were preferred found items of juvenile cunner, and significantly greater numbers of isopods, amphipods and newly settled mussels were present in patches where fish were present than in randomly selected patches.

Experimental and correlative analyses demonstrated that variation in recruitment could not be explained by the presence of conspecifics. …

Characterization Of Activation And Inhibitory Regions In The Adr1 Transcriptional Regulator, Dan Chase

Doctoral Dissertations

The regulation of the ADH2 gene from the yeast Saccharomyces cerevisiae is carbon source-dependent. Expression of ADH2 requires the activity of the transcriptional activator ADR1. This dissertation addresses three separate aspects of the regulation of ADR1 activity.

We have identified eleven additional ADR1$\sp{c}$ mutations which allow ADH2 to partially escape glucose repression. These eleven new mutations cluster to one region of the ADR1 peptide between amino acids 227 and 239, previously identified by four other ADR1$\sp{c}$ mutations. These are the only mutations in ADR1 which have been isolated by virtue of their ability to activate ADH2 transcription under repressed conditions. …

The Characterization Of The Orb Web Of Argiope Aurantia (Araneae: Araneidae) With Emphasis On The Major Ampullate Silk, Cathy Rose Tugmon

Doctoral Dissertations

The orb web of Argiope aurantia was partitioned into a water-soluble and insoluble fraction. The water-soluble fraction was composed of low molecular weight (LMW) molecules ($<$5 kDa) and middle molecular weight (MMW) molecules (14.3 kDa-29 kDa). Choline was one of the principal components of the LMW molecules. This study demonstrated that spiders, like many insects, are unable to synthesize choline from glucose. Attempts to sequence one of the purified MMW proteins were unsuccessful due to the blockage of the N-terminus.

The major emphasis of this research centered on the major ampullate silk of Argiope aurantia. Attempts were made to characterize this silk, both by direct amino acid sequencing and inference from the sequence of a cDNA library clone for one of the major ampullate silk proteins.

To isolate the progenitive silk from the lumen of the major ampullate gland, it was first necessary to inhibit the spider proteases which are known to cleave silk. …

Effects Of Hematopoietic Neoplasia On Physiological Processes In The Soft-Shell Clam, Mya Arenaria (Linne), Mary-Susan Potts

Doctoral Dissertations

Mya arenaria (L.) is susceptible to the disease, hematopoietic neoplasia (Hn), in which atypical cells invade the blood and connective tissue of the clam's organs. In this study impacts of Hn on the reproductive and excretory systems were examined in clams collected from New Bedford Harbor and Little Buttermilk Bay, Buzzards Bay, MA.

The relationships between Hn seasonality and reproduction were evaluated from fresh blood samples and histological analysis of gonads. Both clam populations had biannual reproductive cycles with spawnings in the spring and fall. Hn prevalence exhibited some seasonality with maxima in the fall and late winter-early spring. Reproductive …

Characterization And Inheritance Of The Fused Vein Trait In Squash (Cucurbita Pepo L), Robert Bruce Carle

Doctoral Dissertations

This investigation characterized and determined the inheritance of the fused vein trait in Cucurbita pepo L. with the purpose of evaluating its use as a rouging marker for hull-less seeded cultivars.

The trait is characterized by the partial fusion of the primary leaf veins. There is a reduction in the intraveinal leaf blade and the dorsal leaf surface appears wrinkled. Depending on genetic background, fusion begins with the fourth to tenth leaf stage and continues throughout vegetative growth. The extent of fusion also varies from slight (1-5 cm) to pronounced (15-20 cm). Anatomically, fusion results from an interruption of vein …

Genetic And Molecular Analyses Of Host Symbiotic Genes And An In Vitro Regeneration System For Cicer Arietinum L, Vijayashri Ganapathy Paruvangada

Doctoral Dissertations

Ineffectively nodulating plant mutants PM405B, PM638A, and PM796B were used in molecular/genetic analyses of root nodule formation in chickpea. To establish the mode of inheritance of the mutant nodule phenotype in chickpea mutant PM638A, reciprocal crosses were made between PM638A and wild-type ICC640. The F$\sb2$ segregation data fit a 3 mutants: 1 wild-type monohybrid phenotypic ratio, indicating that ineffective nodulation is due to a monogenic dominant, nuclear mutation, tentatively designated as "Rn$\sb7$". Segregation analysis of F$\sb3$ progeny confirmed this model.

Early (ENod2) and late (Lb) nodulin cDNAs were used as heterologous probes to identify and study the expression of corresponding …