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The University of Calgary master and doctoral theses archive. Full text is made available when possible.
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Browsing Graduate Studies by Department "Biological Sciences"
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Item Open Access 50 kPa anomalies and lightening-caused forest fires in the boreal and subalpine forests of Alberta and Saskatchewan(1995) Nash, Caedmon H.; Johnson, Edward A.Item Open Access A bioenergetic approach to chronic toxicity assessment(1994) Monita, Darwin Michael Anthony; Davies, Ronald W.Item Open Access A Biophysical Characterization of Histone detived Antimicrobial Peptides(2013-09-23) Berezowski, Neil Steven; Prenner, ElmarHistones have been recently shown to be integral to the response of the body to invading pathogens. As such, prior work on this project identified segments of several histones or fragments thereof as potential AMPs. This project comprises a continued biophysical characterization of these selected segments of histone. The project investigates the first generation of AMPs with monolayer models and Brewster angle microscopy to screen for the lipids which are most important in AMP-lipid interactions. Subsequently new variant peptides were designed from one parent peptide (H3) and studied through the use of several thermodynamic and spectroscopic techniques. The variant peptides were shown to be more potent than the parent peptide in terms of microbicidal activity, but were not as selective for bacterial membranes. Therefore, further studies are needed to determine the therapeutic value of the variants.Item Open Access A chemical, biological, and isotopic analysis of the spatial extent of the wastewater effluent on rivers in southern Alberta, Canada(2004) Hogberg, Laureen Kyla; Jackson, Leland J.Chemical, biological, and stable isotope analyses were used simultaneously to track the spatial recovery of rivers from wastewater nutrient enrichment in the Bow and Red Deer Rivers of southern Alberta, Canada during the summers of 2002 and 2003. Exponential models assessed how far downstream it took the rivers to recover to prewastewater conditions. The Red Deer River recovered from nutrient enrichment~ 36, 29, and 70 km downstream according to nutrient concentrations, autotroph biomass and stable isotope values respectively. The Bow River recovered~ 192, 52 and 176 km downstream according to nutrient concentrations, autotroph biomass and stable isotope values. High spatial and temporal variability characterized many indicators. The integration of stable isotopes and autotroph biomass suggests that wastewater alters river food webs. Autotroph biomass and N isotopic composition provided the most timeintegrated measure of conditions and generally displayed the most consistent recovery patterns with distance from the enrichment source.Item Open Access A Comparison of genetic, morphological and physiological traits between salt-tolerant and salt sensitive genotypes of tobacco(1989) Miller, Susan Mary; Thorpe, Trevor A.Item Open Access A comparison of terrestrial arthropods on post-fire forested landscapes under different management regimes in southwestern Alberta(2003) Kinsella, Erin K.; Longair, R. W.I sampled terrestrial arthropods in burned salvaged-logged, burned-unlogged and unburned conifer forest sites in southwestern Alberta. The richness, diversity and abundance of ground beetle (Coleoptera: Carabidae) species and genera, and spider (Araneae) and syrphid genera (Diptera: Syrphidae) were examined. Carabid richness and diversity was highest in the burned-unsalvaged site. However, abundance was similar among the sites. Carabids common to the burned areas included, Trachypachus, Sericoda, Harpalus and Amara species. Overall, yellow pans caught more carabid species and specimens with less sampling than pitfall traps. Spider richness and abundance were greatest in the unburned site. Pardosa predominated across all three sites and the number of web-building genera and specimens were highest in the unburned site. Syrphid richness and abundance were similar across the sites. Richness and abundance declined over the summer with peak capture rates in May-June.Item Open Access A Comparison of two generations of nephelopsis obscura verrill: the effect of prehistory on their energetics and lifehistory traits(1992) Yang, Qian; Davies, Ronald W.Item Open Access A detailed description of newly-discovered remains of Maiasaura peeblesorum (Reptila: ornithischia) and a revised diagnosis of the genus(1995) Trexler, David Lee; Rosenberg, Herbert I.A newly-discovered hadrosaur from the Two Medicine Formation, Teton County, Montana, is described in detail. The description of the skull is the most complete of any produced for a hadrosaur, and the postcranial skeleton provides the first information on an almost complete adult Maiasaura. Information resulting from this detailed examination is used as a base for comparisons with other specimens and reports in the literature. Although the new specimen differs in detail from the holotype, it (OTM F138) was determined to be Maiasaura peeblesorum. This classification led to a revision of the diagnosis of Maiasaura. Several previously unrecognized, taxonomically important characters were identified. The comparisons revealed discrepancies concerning both terminology and interpretation of certain features of the hadrosaur skeleton. These are discussed. In addition, a formula applicable to most hadrosaur specimens was derived for estimating total animal length from the length of the femur.Item Open Access A Genomic and Proteomic Survey of Traits that Modulate Antimicrobial Resistance in Staphylococcus aureus(2024-04-18) MacKenzie, Colin Campbell; Lewis, Ian; Gregson, Daniel; Turner, RaymondAntibiotic resistance is a growing global public health crisis which threatens to remove our primary treatment against bacterial infections. The mechanisms of antibiotic resistance in bacterial pathogens have been extensively studied, however questions surrounding the regulatory mechanisms of these resistance factors in clinical isolates are yet to be answered. In collaboration with the Broad Institute of MIT and Harvard, The Harvard T.H. Chan School of Public Health, and Alberta Precision Laboratories we completed whole-genome sequencing on 7,997 Staphylococcus aureus genomes from a larger study cohort of over 38,000 blood stream infections over a 16-year period. In addition to whole-genome sequencing, the proteomes of the bacterial isolates were quantitatively assessed using Tandem Mass Tag (TMT) ultra-high-performance liquid chromatography mass-spectrometry (UHPLC-MS) methods. Changes in protein levels and growth in the bacterial isolates are related to the variability in the genetic composition of the resistance operons of the specific clinical strains. This study has resulted in the understanding of a complex coregulatory interaction between two resistance operons of Methicillin Resistant S. aureus related to the mecA and blaZ resistance factors. Further, to better understand the metabolic adaptations of pathogens under antibiotic exposure, kinetic flux profiling of Escherichia coli metabolism under various antibiotic stressors was completed through the addition of fully labelled 13C-glucose. This intracellular flux monitoring via UHPLC-MS analysis, at a scale of seconds, has been used to gain insight into the metabolic alterations within E. coli metabolism under the exposure to twelve antibiotics spanning three common classes of antibiotics: DNA synthesis inhibitors, protein synthesis inhibitors, and cell wall synthesis inhibitors. This study has resulted in the classification of important metabolic adaptations occurring because of specific antibiotic compounds. Further, this intracellular metabolic study has shown evidence of a previously unexpected mevalonate pathway in E. coli. These studies have provided insight into the dynamics of pathogen interactions with antibiotics, and a deeper understanding of the antibiotic resistance mechanisms existing in pathogenic strains.Item Open Access A model of fragmentation resulting from human settlement in the Boreal Forest of Saskatchewan(2000) Tchir, Tara L.; Johnson, Edward A.Item Open Access A Molecular biological analysis of organogenesis in cultured radiata pine cotyledons(1992) Thompson, Michael R.; Thorpe, Trevor A.Item Open Access A Morphological study of hepatic hemopoiesis in chicken embryos(1991) Wong, Gene K.; Cavey, Michael J.Hemopoiesis in the liver of the chicken embryo begins on day 7 of incubation (Hamburger and Hamilton Stage 30) and peaks on day 14 (Stage 40). During this time frame, the differentiation of hepatic and hemopoietic cells was studied by light microscopy and by transmission and scanning electron microscopy. Morphometric analyses were performed on the light and electron micrographs. The avian liver is a closely packed array of dendriform cords and discontinuous sinusoids. Hepatocytes are pyramidal in shape, and they ring the bile canaliculi which run through the centers of the hepatic cords. Semithin sections, made possible by infiltration and embedding in glycol methacrylate, were stained with hematoxylin and eosin to reveal the general architecture of the liver, as well as the lipid content of the hepatocytes, and by the periodic acid-Schiff reaction and hematoxylin to visualize the cytoplasmic stores of glycogen. Differentiating hepatocytes were scored for the presence or absence of glycogen and lipid. Glycogen-containing cells fluctuate during early hemopoiesis, but the cell proportion progressively increases toward the hemopoietic peak. Most hepatocytes lack lipid droplets until Stages 39 and 40. From Stage 30 to Stage 35, hepatocyte volume falls to its lowest value. Subsequently (Stages 36 to 40), cell volume increases and hepatocytes achieve a relatively constant size. Ultrastructural changes in the differentiating hepatocytes, including alterations to the mitochondria, endoplasmic reticulum, and Golgi apparatus, were documented. This cell survey was extended to the sinusoidal linings (endothelial cells and Kupffer cells) and to the perisinusoidal cells between the cords and sinusoids. Glycol methacrylate sections were used in lieu of blood smears to study hemopoietic cells, thus overcoming such undesirable traits as cell shrinkage and/or rupture. Sections proved superior to smears for detailed examinations of nuclear and cytoplasmic morphologies and for precise localization of hemopoietic cells to intravascular and extravascular sites. The avian liver, it was found, is directly involved only in erythropoiesis and granulopoiesis. Erythropoietic cells were observed throughout the hemopoietic time frame, but blood islands with granulopoietic cells did not appear until Stage 35. Endothelial cells of the sinusoidal linings are important to erythropoiesis. Asymmetric cell division can release one daughter cell, a proerythroblast, into the circulation, while retaining the other daughter cell in the sinusoidal lining as an endothelial cell. Involvement of endothelial cells in no way discounts a contribution by erythropoietic stem cells. Granulopoiesis in the liver produces only eosinophilic leukocytes. Individual granulopoietic cells appear first in the connective tissue sheaths of hepatic blood vessels, and these cells later congregate into large blood islands. From a comparative standpoint, the elements deemed critical to hemopoiesis in the mammalian liver - the hepatic vasculature, the prehepatocyte population, and the compartments for stem cell differentiation - may not hold the same relevance in the bird. Owing to an inordinate reliance on intravascular hemopoiesis, the relative importance of a prehepatocyte population and individual stem cell compartments is diminished.Item Open Access A mucosal surface model of pseudomonas aeruginosa infections(2012) Nelson, Lisa K.; Ceri, Howard; Turner, Raymond J.In the human body, mucosal sites such as the lungs, eyes, gastrointestinal tract and urinary tract are often the target of bacterial infections. One of the most notorious bacterial species known to infect mucosal surfaces is the opportunistic pathogen Pseudomonas aeruginosa. As such, there has been much research devoted to studying the mechanisms by which P. aeruginosa infects these surfaces, particularly how it causes chronic infections as these infections are problematic and difficult to eradicate. However, because P. aeruginosa is an opportunistic pathogen - in that it typically causes infection of mucosa! sites when they are compromised by disease, injury, or implanted medical devices - it has proved difficult to model infections by these bacteria. Consequently, in this work, we hypothesized that we could develop a novel model using the rat prostate for studying acute and chronic P. aeruginosa infections at mucosal surfaces. Unlike current mammalian models of chronic infections, this model has an advantage: chronic infections can easily form at the prostate mucosal surface without foreign body assistance. Therefore, using this model, we were able to study how chronic P. aeruginosa infections were influenced by processes that occur within the biofilm - a mode of adherent bacterial growth that is resistant to clearance. We found that signalling via quorum sensing was required to maintain a chronic infection, but this was likely due to its role in biofilm function rather than formation. We also showed, for the first time, that generation of variants associated with biofilm growth occurred in vivo using similar genetic pathways previously identified in vitro. Furthermore, we ascertained that the generation of variants could be critical for maintaining an infection, and that a heterogeneous population of variants was produced during mucosal surface infections. Finally, we expanded on the utility of our model and showed that diversity via multi-isolate infections affected chronic P. aeruginosa virulence. Thus, altogether, using our novel prostate model we were able to determine that signalling and diversity generation were important for chronic P. aeruginosa infections at mucosa! surfaces. These findings should have important implications for the development of better therapeutics against P. aeruginosa.Item Open Access A multinuclear NMR investigation of the metal ion and anion binding sites of transferrins(1996) Saponja, Jillian Ann; Vogel, Hans J.Item Open Access A Novel regulator of translation during early development of xenopus laevis(1991) Fu, Loning; Browder, Leon W.Item Open Access A Preliminary study of pollen allergies in the city of Calgary(1988) Dudar, Cheryl M.; Chinnappa, C. C.Several aspects of pollen allergy studies were investigated in ~he city of Calgary, Alberta, Canada during the period of May 1, 1987-April 27, 1988. Calgary was ideal for these studies since little information is available about the cause and treatment of pollen allergies in this area. The goals of the study were to sample and describe the pollen airload throughout the city, interpret the changes in pollen airload in relation to the environment, and describe the allergy patient population of Calgary. Prior to pollen sampling, a reference collection of pollen was compiled from the known distributions of native and introduced plants in the area. Twelve pollen categories were defined based on grain structure and size: Populus, Acer, Salix, Betula, Ulmus, Artemisia, Chenopods, Grasses, Trifolium, Medicago, Taraxacum, and Composites. Pollen was sampled in 11 locations (6 designated and 5 randomly chosen) throughout Calgary using a pollen sampler designed for this study. The new sampler is unpowered, uses acetate fibers as a collection surface, and has a design similar to a Tauber trap[Tauber, 1974]. The absolute counts from the sampling locations were analyzed by a blocked ANOVA with the time periods of sampling used as the blocking units. The counts were found to be similar in the Riverside designated site and the randomly chosen locations. These areas were then grouped together and called the Residential sampling area. The Residential area is probably the most typical pollen area for Calgary. Four other areas were identified by the ANOVA: Grassland, Developed Park, Undeveloped Park, and Business District. The different counts in these areas reflected the type and amount of local allergenic pollen producers. A typical pollen calendar for Calgary was defined using the Residential area counts. The early Spring season pollinators in Calgary were Acer and Populus. Betula and Salix did not appear until May and Ulmus never had a true peak period. All tree pollen in the air decreased greatly after May. During the Summer, Grasses, Chenopods and Artemisia were the most significant pollen types . The weather patterns during the 1 year sampling period were compared to the pollen counts of the 5 areas. A temperature increase to between 5°C and 15°C was found to be necessary for at least 2 weeks prior to tree pollination. Weed and grass pollen appeared after at least 2 weeks of moderate temperatures of 10°C to 15°C. It was probably the combined effect of increased photoperiod and warmer temperatures which caused the pollination. Precipitation did not seem to decrease pollen counts in all areas. The pollen sampler's efficiency in wet conditions may, however, have obscured these findings. Wind direction did correlate with higher counts when the wind came from a direction where it encountered many pollen producers. The allergy patient population in Calgary was found to be normally distributed. There was some indication that a positive skin test reaction to any tree or grass pollen could correlate with sensitivities to other tree or grass extracts. The patient survey indicated that the 12 allergenic pollen categories contributing to the airload in Calgary should be emphasized in skin tests for pollen allergies. The continued monitoring of Calgary pollen airloads would also assist in improving the treatment and detection of pollen allergies in Calgary.Item Open Access A study of Neurospora genes encoding NAD+- specific glutamate dehydrogenase (gdh) and heat shock protein 80 (hspe-1) by repeat-induced point mutations(1994) Vijayaraghavan, Yamini; Kapoor, ManjuItem Open Access A study of the C. elegans teg-4 gene, using Tiling array analysis(2011) Zhao, Xuan; Hansen, DavidItem Open Access Item Open Access A study of UV resistance and plant ecophysiology using type II CPD DNA photolyase as a molecular marker in stellaria longipes(2004) Wu, William Tam-Shui; Reid, David M.; Chinnappa, C. C.