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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 …
Image Correlation Spectroscopy: Development And Application To Studies Of Pdgf Receptor Distributions, Paul William Wiseman
Image Correlation Spectroscopy: Development And Application To Studies Of Pdgf Receptor Distributions, Paul William Wiseman
Digitized Theses
Aggregation of macromolecular plasma membrane receptors following ligand binding is hypothesized to be the initial step in signal transduction in cellular systems. Quantitative measurement of receptor distributions on cell surfaces is integral for elucidating the complicated mechanisms involved in transduction of chemical signals across the cells membrane. Scanning fluorescence correlation spectroscopy (S-FCS) has been used successfully to perform quantitative measurements of receptor densities and aggregate sizes. However, these measurements take a great deal of time, and require specialized equipment to implement. Here, image correlation spectroscopy (ICS) is introduced as a novel extension of scanning fluorescence correlation spectroscopy that improves on …
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 …
Genome Organization, Replication And Movement Of Foxtail Mosaic Virus, Michele Rouleau
Genome Organization, Replication And Movement Of Foxtail Mosaic Virus, Michele Rouleau
Digitized Theses
Foxtail mosaic virus (FMV) is a member of the potexvirus family which infects primarily monocotyledonous plants. Its flexuous filamentous particles are 500 nm long and consist of a messenger sense RNA encapsidated by a single type of coat protein. We have determined the nucleotide sequence of the FMV gRNA as well as the organization of its coding sequences. The gRNA is 6151 nucleotides long and contains five major open reading frames (ORF). The amino acid sequences of the putative proteins are closely related to homologous proteins of other sequenced potexviruses.;A procedure for the partial purification of the RNA-dependent RNA polymerase …
Structural Basis For Human Anti-Dna Antibody Specificity, Mahmoud Mahmoudi
Structural Basis For Human Anti-Dna Antibody Specificity, Mahmoud Mahmoudi
Digitized Theses
Anti-DNA antibodies are hallmarks of SLE both in human and inbred lupus prone mice. The role of these antibodies in disease pathogenesis, particularly in glomerulonephritis has been documented. It is now well accepted that the genetic potential to generate anti-DNA antibodies also exists in the normal B cell immune repertoire. This genetic potential has been revealed by detection of anti-DNA antibodies in serum of normal individuals and by immortalizing DNA reactive B cells as hybridomas and as transformed cell lines. There is growing evidence that anti-DNA antibodies from the normal B cell repertoire and disease-associated anti-DNA antibodies share V region …
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 …
Modulation Of Experimental Allergic Encephalomyelitis In The Sjl/J Mice By Cytokines And Anti-Cytokine Antibodies, Trang Thi Duong
Modulation Of Experimental Allergic Encephalomyelitis In The Sjl/J Mice By Cytokines And Anti-Cytokine Antibodies, Trang Thi Duong
Digitized Theses
Immunization with myelin basic protein in complete Freund's adjuvant resulted in only mild chronic-relapsing experimental allergic encephalomyelitis (EAE) with very low incidence in SJL/J mice, and no disease at all in A/J, BALB/c, C3H/HeJ, DBA/2, AKR and NZW mice. However, treatment of mice with anti-IFN{dollar}\gamma{dollar} (aIFN) monoclonal antibody (mAb) at the time of immunization determined severe disease in all those strains except AKR. Similarly, the passive induction of EAE in the SJL/J mice and in two of three resistant strains examined was significantly enhanced by aIFN mAb administration. In the SJL/J mice, administration of anti-interleukin 2 (aIL2) mAb had only …
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 …
Prenatal Risk Factors For Neurological Abnormalities In The Term And Near Term Neonate, Kathleen Owen O'Connor
Prenatal Risk Factors For Neurological Abnormalities In The Term And Near Term Neonate, Kathleen Owen O'Connor
Digitized Theses
An abnormal neurological examination in the neonatal hospital stay may indicate a transient or permanent neurological disturbance. Abnormal neurological symptoms therefore place an infant at increased risk for subsequent neurological problems.;This case-control study was designed to investigate prenatal and perinatal risk factors for an abnormal neurological examination in the term infant. Infants were born between 1 January, 1988 and 30 June, 1990. The sample consisted of 222 neonates with neurological abnormalities and 666 controls who were free of such problems. Data on the prenatal histories of their mothers, course of the pregnancy, intrapartum events and status of the infant after …
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 …
High Resolution And Wideline Nmr Studies Of Membrane Associated Molecules Involved In Signal Transduction, Alan Cavell Rigy
High Resolution And Wideline Nmr Studies Of Membrane Associated Molecules Involved In Signal Transduction, Alan Cavell Rigy
Digitized Theses
The primary focus of our investigations were centered around understanding the biochemical basis of the early events involved in signal transduction. Our work has involved two novel systems: (1) sphingolipid metabolites and (2) a synthetic peptide representing the transmembrane region of the human epidermal growth factor receptor (hEGFR).;Sphingolipid metabolites have emerged as physical modulators of many signalling pathways, including cell growth regulation, and signal transduction. N,N-({dollar}\sp2{dollar}H{dollar}\sb6{dollar}) -dimethylsphingosine and ({dollar}\sp2{dollar}H{dollar}\sb4{dollar}) -lysogalactosyl ceramide were produced by partial synthesis and studied via wideline {dollar}\sp2{dollar}H NMR, as a function of pH. Spectra of ({dollar}\sp2{dollar}H{dollar}\sb6{dollar}) -dimethylsphingosine identified that the molecule's orientation and behaviour are largely …
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, …
Role Of Protein Kinase C In Mediating The Effects Of Physiological And Pathophysiological Interventions In The Heart, Christopher Andrew Ward
Role Of Protein Kinase C In Mediating The Effects Of Physiological And Pathophysiological Interventions In The Heart, Christopher Andrew Ward
Digitized Theses
Protein kinase C has been implicated as a mediator of myocardial function following both physiological and pathophysiological stimuli. The purpose of the present study was to examine the functional effects of PKC in mediating phorbol esters as well as receptor-induced effects in myocardial tissues. Additionally, the possible role of PKC in mediating cardiac pathophysiology was assessed under conditions which mimicked aspects of myocardial ischemia/reperfusion. The effects of phorbol esters on cardiac function were assessed in isolated perfused guinea pig hearts. The effects of phorbol esters, acidosis/realkalinization and hydrogen peroxide were assessed in isolated guinea pig ventricular myocytes to determine PKC-dependent …
The Influence Of Extremely Low Frequency Magnetic Fields On Cytosolic-Free Calcium In Human Cells, Jeffrey John Carson
The Influence Of Extremely Low Frequency Magnetic Fields On Cytosolic-Free Calcium In Human Cells, Jeffrey John Carson
Digitized Theses
Extremely low frequency (ELF) magnetic fields have been reported to affect Ca{dollar}\sp{lcub}2+{rcub}{dollar}dependent biological processes. Based on these reports, I hypothesized that cystosolic free calcium concentration ({dollar}\lbrack\rm Ca\sp{lcub}2+{rcub}\rbrack\sb{lcub}i{rcub}){dollar} may be influenced by ELF magnetic fields and found an increase in HL-60 cells following exposure {dollar}(P0.09).{dollar} However, experiments with indo-1-loaded Jurkat cells indicated frequency- and field strength-dependent effects on resting and mitogen-stimulated {dollar}\lbrack\rm Ca\sp{lcub}2+{rcub}\rbrack\sb{lcub}i{rcub}{dollar} levels {dollar}(P<0.01).{dollar} The findings show that ELF magnetic fields affect {dollar}\lbrack\rm Ca\sp{lcub}2+{rcub}\rbrack\sb{lcub}i{rcub}{dollar} and may explain some of the reported Ca{dollar}\sp{lcub}2+{rcub}{dollar}-dependent biological effects of ELF magnetic fields.
Examination Of Nucleoside Transport In The Mammalian Nervous System, Kenneth William Jones
Examination Of Nucleoside Transport In The Mammalian Nervous System, Kenneth William Jones
Digitized Theses
In rabbit and guinea pig cortical synaptosomes, the nucleoside transport inhibitors nitrobenzylthioinosine and dipyridamole were used to test the hypotheses that the nitrobenzylthioinosine-sensitive and -resistant ({dollar}\sp3{dollar}H) dipyridamole binding sites are associated with the es and ei nucleoside transporters, respectively. In addition, the hypothesis that the es and ei nucleoside transporters in rabbit cortical synaptosomes differ in their selectivity for compounds besides nitrobenzylthioinosine was tested, Nitrobenzylthioinosine-sensitive ({dollar}\sp3{dollar}H) dipyridamole binding and ({dollar}\sp3{dollar}H) nitrobenzylthioinosine binding involved the same site on the es transporter. The relative proportions and inhibitor sensitivities of nitrobenzylthioinosine-resistant ({dollar}\sp3{dollar}H) dipyridamole binding could not be correlated with nitrobenzylthioinosine-resistant nucleoside transport. This, …
Social Rank And Foraging Behavior In Rats: Effects Of Food Size, Density And Distribution, Maria Phelps
Social Rank And Foraging Behavior In Rats: Effects Of Food Size, Density And Distribution, Maria Phelps
Digitized Theses
A number of field studies, conducted with birds, have found that dominant birds aggress against subordinate birds to attain priority of access to food. However, the level of aggression exhibited by dominant birds varied in accord with a cost-benefit analysis of the physical properties and spatial organization of the resource base. When the costs of aggression exceeded the benefits gained from resource defense, dominant birds decreased the level of aggression. Because rats also forage in groups and form functional social hierarchies, it was predicted that dominant rats, like dominant birds, would decrease aggression as a function of three resource attributes. …
Postsynaptic Cholinergic Control Of Cardiac Function In Aging, Na Su
Postsynaptic Cholinergic Control Of Cardiac Function In Aging, Na Su
Digitized Theses
The present study using isolated constant flow-perfused heart from adult (8 month-old) and aged (26 month-old) Fischer 344 rats for the first time demonstrated a striking enhancement of the negative chronotropic, inotropic and coronary vasoconstriction responses of the aging heart to postsynaptic cholinergic stimulation.;The approaches used and the results demonstrated were the following. (i) Acetylcholinesterase activity measured by the method of Ellman et al (1961) declined significantly in the atria and ventricles of the aged compared to adult rats. (ii) No age-related difference was seen in muscarinic receptor number in the atria and ventricles as assessed by {dollar}\lbrack\sp3\rm H\rbrack QNB{dollar} …
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 …
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 Effects Of Preadministration Of Nmda Antagonists On Kindling With Carbachol, Deborah Michelle Saucier
The Effects Of Preadministration Of Nmda Antagonists On Kindling With Carbachol, Deborah Michelle Saucier
Digitized Theses
This thesis evaluated the hypothesis that N-methyl-D-aspartate (NMDA) receptor activity is essential for the development of kindling and/or the maintenance of the kindled state in male hooded rats. Kindling was produced by the infusion of carbachol, a muscarinic cholinergic agonist, directly into either the basolateral nucleus of the amygdala or the dentate gyrus of the hippocampus. The infusions of carbachol took place over 70 seconds and were given every 2 days. At a previously determined time before the infusion of carbachol, either APV (DL-aminophosphonovaleric acid, infused into the site of recording) or NPC 17742 (2R,4R,2S-(2-amino-4,5(cyclohexyl)-7-phosphonoheptanoic acid, i.p.) was given. Both …
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 …