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Effects Of Industrial Effluents On Populations Of The Freshwater Mussel Lampsilis Radiata In The St Lawrence River, Lee Curtis Grapentine
Effects Of Industrial Effluents On Populations Of The Freshwater Mussel Lampsilis Radiata In The St Lawrence River, Lee Curtis Grapentine
Digitized Theses
The objective of this study was to assess the effects of industrial discharges, contaminated primarily with trace metals, on populations of Lampsilis radiata (Bivalvia: Unionidae) in the upper St. Lawrence River. Effects on shell growth were examined by (a) comparing growth curves derived from analyses of external annual rings of clams sampled from sites located upstream and downstream of four localized sources of discharges, and (b) measuring shell growth for one year from clams that were transplanted into contaminated and uncontaminated sites. Allozyme frequencies in clams from above and below discharges were determined for glucose-phosphate isomerase (GPI) and phosphoglucomutase (PGM), …
The Function Of Sarcoplasmic Reticulum In The Aged Rat Heart, Ming Tao Jiang
The Function Of Sarcoplasmic Reticulum In The Aged Rat Heart, Ming Tao Jiang
Digitized Theses
The purpose of this project was to study the effect of aging on the regulation of Ca{dollar}\sp{lcub}2+{rcub}{dollar} by cardiac sarcoplasmic reticulum (SR) and its potential contribution to the age-related alterations in myocardial contractile performance in Fischer 344 rats.;In cardiac membranes enriched in SR (MSR) and its light (LSR) and heavy (HSR) subfractions fractionated by a sucrose density gradient, the rate of ATP-supported and oxalate-facilitated Ca{dollar}\sp{lcub}2+{rcub}{dollar} uptake was significantly reduced (24-50%) in the aged (26-30 months old) compared with that of the adult rats (6-8 months old). With aging, the Ca{dollar}\sp{lcub}2+{rcub}{dollar}-stimulated phosphoenzyme of the Ca{dollar}\sp{lcub}2+{rcub}{dollar} pumps was reduced in MSR, LSR …
The Regulation Of A Type Iv Phosphodiesterase From L6 Myoblasts, A Thomas Kovala
The Regulation Of A Type Iv Phosphodiesterase From L6 Myoblasts, A Thomas Kovala
Digitized Theses
A potential role for cAMP in regulating the differentiation of myoblasts has lead to the examination of the components of the cAMP signalling system, in this case a cyclic nucleotide phosphodiesterase (PDE). A Type IV PDE isozyme was identified in L6 myoblasts using consensus sequence PCR primers, and its regulation by cAMP studied. Sequencing of RT-PCR products showed the presence of a Type IV PDE mRNA known as ratPDE 3.1. High levels of cAMP induced dramatic increases in the PDE mRNA levels as demonstrated by northern blot analysis. Run-off transcription experiments showed increased rates of transcription. L6 myoblasts which had …
Photosynthetic Acclimation To Light And Temperature: Excitation Pressure And Redox Sensing, Denis Philip Maxwell
Photosynthetic Acclimation To Light And Temperature: Excitation Pressure And Redox Sensing, Denis Philip Maxwell
Digitized Theses
Photosynthetic acclimation to low temperature has been studied extensively. However, since low temperature causes a preferential decrease in the rates of biochemical as compared to photochemical reactions, some alterations brought about by acclimation to low temperature may be the result of the light-harvesting apparatus absorbing more light energy than can be readily dissipated through photosynthesis. This possibility was investigated by using two species of green algae, Chlorella vulgaris and Dunaliella salina and the techniques of chlorophyll a fluorescence, O{dollar}\sb2{dollar}-evolution, protein electrophoresis and Western blotting, high performance liquid chromatography, RNA blot hybridization, and enzyme and metabolite assays. Compared to algae grown …
The Interaction Of Thyroid Stimulating Hormone (Tsh), Insulin-Like Growth Factors (Igfs), And Insulin-Like Growth Factor Binding Proteins (Igfpbs) In The Regulation Of The Synthesis And Secretion Of Thyroid Hormones By Cultured Sheep Thyroid Cells, Jia Fang Wang
Digitized Theses
Thyroid growth and function are regulated by TSH in synergy with other hormones, growth factors, and neurotransmitters. Insulin-like growth factors (IGFs), which have insulin-like effects on metabolism and regulate cell growth and function, are synthesized and secreted by thyroid cells. IGFs are associated with their specific binding proteins (IGFBPs), which not only carry and store IGFs in body fluids but also modulate the biological function of IGFs. Previous studies found that both IGFs and IGFBPs participated in the regulation of the growth of thyroid cells.;This study has further examined the biological function of IGFs and IGFBPs in the regulation of …
Structure/Function Analyses Of Sex Hormone-Binding Globulin, Wayne Peter Bocchinfuso
Structure/Function Analyses Of Sex Hormone-Binding Globulin, Wayne Peter Bocchinfuso
Digitized Theses
Sex hormone-binding globulin (SHBG) is a homodimeric glycoprotein that transports sex steroids in the blood and extravascular fluids, such as seminiferous tubule fluid, where it is often referred to as androgen-binding protein (ABP). A cDNA for the human SHBG precursor polypeptide was expressed in mammalian cell lines. Recombinant human SHBG bound steroids with the same affinity and specificity as natural SHBG, and was immunologically indistinguishable from its natural counterpart. Site-directed mutagenesis of the SHBG cDNA was used to introduce amino acid substitutions that selectively removed glycosylation sites from SHBG. Analysis of these glycosylation mutants demonstrated that carbohydrates are not involved …
Programming Of Muscle Activity In Arm Movements In Relation To Force Requirements, Naznin Virji-Babul
Programming Of Muscle Activity In Arm Movements In Relation To Force Requirements, Naznin Virji-Babul
Digitized Theses
Analysis of the relationship between movement kinematics and muscle activity is a widely used approach for understanding how the nervous system formulates motor commands to produce movements. In planar single joint movements, phasic muscle activity is highly correlated with specific kinematic variables. Such correlations have not proven to be as direct in complex movements. The rules used by the nervous system in movement coordination are thus poorly understood. The purpose of this study was first, to examine kinematics, dynamics and electromyographic (EMG) activity during single and two-joint arm movements to discern the common planning strategies between these movements; and second, …
Transcriptional Regulation Of The Urea Cycle Enzyme Genes In The Liver Of Rana Catesbeiana Tadpoles During Spontaneous And Thyroid Hormone-Induced Metamorphosis, Yuqing Eugene Chen
Transcriptional Regulation Of The Urea Cycle Enzyme Genes In The Liver Of Rana Catesbeiana Tadpoles During Spontaneous And Thyroid Hormone-Induced Metamorphosis, Yuqing Eugene Chen
Digitized Theses
The ornithine urea cycle enzymes, carbamyl phosphate synthetase (CPS-1), ornithine transcarbamylase (OTC) and arginase, are liver-specific proteins. Their expression is coordinately activated during the metamorphosis of the Rana catesbeiana tadpole by thyroid hormone (TH), and their presence is critical for the shift of this amphibian from an aquatic, ammonotelic larva into a terrestrial, ureotelic adult. My studies were focused on analyzing the transcriptional regulation of the genes encoding these urea cycle enzymes and determining whether these genes were upregulated directly or indirectly by TH. With this thought in mind, I isolated and characterized the sequences in the promoter regions of …
Neurotransmission Of Visceral Information In The Parabrachial Nucleus Of The Rat, Tarek Saleh
Neurotransmission Of Visceral Information In The Parabrachial Nucleus Of The Rat, Tarek Saleh
Digitized Theses
The parabrachial nucleus (PB) has been shown to be a major relay site for visceral afferents ascending through the ventrobasal thalamus and terminating in the insular cortex. The purpose of these investigations was to determine the neurotransmitter mechanisms in the PB involved in relaying visceral sensory information to the thalamus in the rat. Using electrophysiological techniques in the cloral hydrate anesthetised male Wistar rat, our results show that the visceral pathway from the PB to the thalamus appears to use two neuronal systems, one mediating the relay of specific visceral information via glutamatergic N-methyl D-aspartate (NMDA) receptors in the PB, …
The Putative Role Of Fatty Acids In The Activation Of Trehalose Synthesis In The Fat Body Of The Cockroach Periplaneta Americana L, Irshad Ali
Digitized Theses
Hypertrehalosemic hormones produced by the corpus cardiacum increase the concentration of several fatty acids in cockroach fat body trophocytes. The phospholipase A{dollar}\sb2{dollar} (PLA{dollar}\sb2){dollar} activator melittin has a similar effect. The fatty acids include palmitic, stearic, oleic and linoleic acid. The hormone mediated release of these fatty acids is blocked by the PLA{dollar}\sb2{dollar} inhibitors mepacrine and {dollar}\rho{dollar}-bromophenacyl bromide. These observations suggest that hormonal release of fatty acids, may be due to the activation of PLA{dollar}\sb2.{dollar};The increase in non-esterified fatty acids appears to be linked to the increase in trehalose efflux since sugar efflux is stimulated by stearic, oleic, linoleic and arachidonic …
Mechanisms Of Autonomic Control By The Insular Cortex In The Rat, Kenneth Scott Butcher
Mechanisms Of Autonomic Control By The Insular Cortex In The Rat, Kenneth Scott Butcher
Digitized Theses
The insular cortex (IC) has been proposed to act as visceral sensory and autonomic cortex. The mechanism of control by the IC, however, is not clear. The nature of insular cortical function in hypertension is also unknown.;Middle cerebral artery occlusion (MCAO) in Wistar rats has been shown to cause cortical infarction, including the IC, resulting in increases in sympathetic nerve discharge (SND). MCAO in the urethane anesthetized spontaneously hypertensive rat (SHR) resulted in decreases in arterial pressure (AP) and SND.;To determine if the autonomic effects of MCAO in the SHR and Wistar rat are due to insular damage, a lesion …
Characterization Of Fungal Fimbriae, Martina Celerin
Characterization Of Fungal Fimbriae, Martina Celerin
Digitized Theses
Fungal fimbriae are surface appendages that were first described by Poon and Day (1974) on the haploid cells of Microbotryum violaceum. They are long (1 to 20 {dollar}\mu{dollar}m), narrow (7 nm) flexuous fibres that were implicated in important cellular functions such as mating and pathogenesis. Since this initial description, numerous other fungi from all five phyla have been shown to produce fimbriae on their extracellular surfaces. Because they are easy to purify, the fimbriae from M. violaceum have been investigated most extensively. The present study extends the earlier characterizations of M. violaceum fimbriae, and expands on the biochemical description of …
Evolutionary Dynamics At Two Loci Of The Human Genome As Assessed By Examination Of Nucleotide Sequence Diversity And Organization, Kathleen Allen Hill
Evolutionary Dynamics At Two Loci Of The Human Genome As Assessed By Examination Of Nucleotide Sequence Diversity And Organization, Kathleen Allen Hill
Digitized Theses
Accurate and comprehensive measurement of the extent and pattern of nucleotide diversity is necessary to refine theories on the dynamics of evolution. It is possible to determine the sequence of any genomic region for numerous individuals using the polymerase chain reaction (PCR) and associated techniques of DNA sequence analysis. The two regions of the human genome examined in this study were the third exon of the highly conserved (two major alleles) alcohol dehydrogenase, Adh2 locus and the second exon of the highly polymorphic (26 alleles) human leukocyte antigen, HLA-DQ{dollar}\beta{dollar}1 gene. Sequence information was determined from 25 individuals from Southwestern Ontario …
Developmental Potential Of Rat Myoblast Lineages, Christopher Louis Pin
Developmental Potential Of Rat Myoblast Lineages, Christopher Louis Pin
Digitized Theses
Skeletal muscle consists of multinucleated fibres which are classified as slow (I) or fast (IIA, IIB, IIX) muscle fibre types which differ in their contractile properties and their expression of contractile protein isoforms. Individual muscles contain characteristic distributions of fibre types which can be identified based on their myosin heavy chain (MyHC) content. While classical studies have demonstrated that the fibre type composition of adult muscles can be altered by extrinsic factors (such as changes in the pattern of innervation), recent studies suggest that different fibre types may be formed from distinct myoblast lineages. The purpose of this study was …
Epidermal Growth Factor Regulation Of Porcine Oocyte Maturation And Cumulus Cell Expansion In Vitro, Balwant Singh
Epidermal Growth Factor Regulation Of Porcine Oocyte Maturation And Cumulus Cell Expansion In Vitro, Balwant Singh
Digitized Theses
The overall objective of this study was to investigate the role in vitro of epidermal growth factor (EGF) in the regulation of both nuclear and cytoplasmic maturation of the porcine oocyte, and in the expansion of cumulus cells.;Studies aimed at the induction of oocyte maturation and cumulus expansion revealed that EGF is a potent stimulant of the resumption of meiosis in the oocyte and that the addition of FSH, but not LH, to EGF further enhances its effect on germinal vesicle breakdown (GVBD). Both estradiol-17{dollar}\beta{dollar} (E{dollar}\sb2{dollar}) and androstenedione (A{dollar}\sb4{dollar}) inhibited FSH-stimulated GVBD, but had no effect on EGF-stimulated GVBD, suggesting …
Feedback Control Mechanisms Regulating Breathing In Humans, Croix Claudette St
Feedback Control Mechanisms Regulating Breathing In Humans, Croix Claudette St
Digitized Theses
The respiratory system regulates alveolar ventilation (V{dollar}\sb{lcub}\rm A{rcub}{dollar}) almost exactly to the demands of the body so that the PCO{dollar}\sb2{dollar} and PO{dollar}\sb2{dollar} of the arterial blood are hardly altered, even during strenuous exercise or other types of respiratory stress. The feedback control of ventilation was studied in human subjects using the technique of dynamic end-tidal forcings to produce perturbations in end-tidal PCO{dollar}\sb2{dollar} (P{dollar}\sb{lcub}\rm ET{rcub}{dollar}CO{dollar}\sb2{dollar}) and end-tidal PO{dollar}\sb2{dollar} (P{dollar}\sb{lcub}\rm ET{rcub}{dollar}O{dollar}\sb2{dollar}) to stimulate the respiratory chemoreceptors.;The purpose of the first study was to investigate the interaction between ventilatory drives from the central (cR{dollar}\sb{lcub}\rm c{rcub}{dollar}) and peripheral (pR{dollar}\sb{lcub}\rm c{rcub}{dollar}) chemoreceptors using their different …
The In Vitro Studies On Phage Mu Transposase, Zhenguo Wu
The In Vitro Studies On Phage Mu Transposase, Zhenguo Wu
Digitized Theses
Bacteriophage Mu is one of the model systems to study DNA transposition. The availability of an in vitro soluble system greatly facilitates the dissection of the transposition mechanisms at the molecular levels. Several aspects of the in vitro mini-Mu DNA transposition have been dealt with in this thesis.;First, the flanking host DNA sequences on the strand cleavage step mediated by Mu transposase (Mu A protein) was investigated. We found that certain flanking host sequences could inhibit the strand cleavage step without affecting the earlier synapsis step. Furthermore, this cleavage defect could be overcome by the Mu B protein in the …