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Development And Characterization Of An Inducible Rnai System In Toxoplasma Gondii, Biju Vasavan

Electronic Theses and Dissertations

Toxoplasma gondii is a ubiquitous protozoan parasite that can infect and replicate within any nucleated mammalian or avian cell. The ability of double stranded RNA to downregulate gene expression has been demonstrated in T. gondii. We have constructed a tetracycline based inducible RNAi vector which can be used for regulating gene expression in T. gondii. Upon the addition of anhydrotetracycline, the production of double stranded RNA homologous to the target gene is induced. The inducible vector was characterized using the marker gene, uracil phosphoribosyl transferase. The inducible vector was stably transfected into RHtetR strain of the parasite and …

Multiple Social And Ecological Factors Influence Coloration In Bluegills (Lepomis Macrochirus), Karen Michelle Cogliati

Electronic Theses and Dissertations

Antagonistic interactions between sexual and natural selection influence the evolution of ornamental signals. I investigated possible functions of colourful traits in bluegills (Lepomis macrochirus). First, I conducted a descriptive study among eight lakes in Ontario to determine how colour traits varied with age, sex, season, and condition. My findings identified breast, cheek and opercular flap coloration as possible sexual ornaments. Subsequently, I investigated the role of sexual selection on coloration through observations of spawning bluegills. Results suggest that breast and cheek coloration influence female spawning behaviour and male reproductive success. Finally, I investigated effects of ecological factors on coloration. Vegetation …

Chemical Exposure Dynamics Of Polychlorinated Biphenyls (Pcbs) And Organochlorine Pesticides (Ocs) In Green Frog (Rana Clamitans ) And Bullfrog (Rana Catesbeiana) Tadpoles, Kimberley Mccormack

Electronic Theses and Dissertations

Studies were conducted to determine the effects of different environments and temperatures on chemical exposure dynamics in tadpoles. In the first study, green frog tadpoles (Rana clamitans) were dosed with Performance Reference Compound polychlorinated biphenyls (PRC PCBs) and placed into agricultural, municipal and reference watersheds near Windsor, Ontario, Canada. PRC PCBs were eliminated significantly faster than in previous laboratory studies, with elimination rate coefficients between 0.200 and 1.295 day-1. Tadpoles reached steady state within 23 days and tracked differences in chemical bioavailability among sites.

The elimination of PRC PCBs and DDT were evaluated in green frog and bullfrog …

Wdr1 And Its Isoform Alter Neurite Extension In Pc12 Cells, Renée N. Tousignant

Electronic Theses and Dissertations

WDR1 is an actin binding protein which promotes actin cytoskeletal rearrangement. Our lab has discovered a truncated isoform of mammalian WDR1, which lacks exons 3-5 (WDRΔ35). The function of both WDR1 and WDRΔ35 has not been characterized. The role of WDR1 and WDRΔ35 in neurite extension was examined using qRT-PCR. The WDR1 RNA levels increased during neurite extension in PC12 cells whereas WDRΔ35 RNA levels decreased. Similarity, the overexpression of WDR1 in PC12 cells increased neurite extension whereas WDRΔ35 overexpression decreased neurite number and length. qRT-PCR was also utilized to examine WDR1 and WDRΔ35 RNA levels during mouse brain development. …

A Model Of Sporadic Parkinson's Disease: Herbicide Induced Parkinson's Disease In Rat And Neuroprotection By Water Soluble Coq10, Mallika Somayajulu

Electronic Theses and Dissertations

Parkinson's disease is caused due to the progressive loss of dopaminergic neurons in the brain. Less than 10% of cases have a strict familial etiology while more than 90% are sporadic. The mechanisms underlying neuronal cell death in Parkinson's disease have not been fully elucidated. Furthermore, there is currently no therapy available to prevent the progressive loss of neurons in Parkinson's disease. The objective of my research was to establish a sporadic model of Parkinson's disease and evaluate the neuroprotective effects of water soluble Coenzyme Q10. In this study, a model of paraquat-induced neurodegeneration in rats was used to evaluate …

Sexual Selection And Sperm Competition In The Guppy ( Poecilia Reticulata), Karen Elizabeth Elgee

Electronic Theses and Dissertations

When differences among individuals in the ability to acquire mates result in evolutionary change, this is known as sexual selection. My goal was to investigate sexual selection on male traits in the guppy (Poecilia reticulata). I assessed reproductive skew and correlates of male reproductive success in a wild population and found that male reproductive success was strongly skewed and correlated with gonopodium length, but not with the relative area of coloured spots, body length, or sperm velocity. I then determined the role of sperm competition in shaping sperm form and function by comparing sperm traits across populations. I found that …

Influences Of Tailings Water, Sediments, Macrophytes And Detritus On Zoobenthic Community Development In Constructed Wetlands –Results Of A Reciprocal Transplant Study, Lyndon Barr

Electronic Theses and Dissertations

Constructed wetlands using oil sand process materials are being used by the oil sands mining corporations to reclaim the post-mining landscape. A reciprocal sediment transplant study was conducted to measure effects of sediment, water, plant cover, detritus mass and year to year variation on zoobenthic richness, density and relative abundance. Density did not change between wetlands, but the oil sand process water-affected wetland had lower richness than the reference wetland. Zoobenthic relative abundance was influenced by water type, macrophyte density and amount of accumulated detritus in sediment. Zoobenthos density was significantly positively associated with amount of plant cover and detritus …

Gene Flow & Dispersal As Factors Mediating Population Divergence, Admixture And Speciation In Fishes, Ryan P. Walter

Electronic Theses and Dissertations

Understanding how species persist and how they arise are among the most fundamental objectives of ecology and evolutionary biology. Genetic markers coupled with population genetic theory are frequently employed in the study of animal dispersal and gene flow, two parameters central to understanding the genetic structure underlying natural populations.

This thesis presents novel examples of the temporally-stabilizing effect of low to moderate levels of gene flow (Chapter 2), population admixture or evidence of sympatric divergence (Chapter 3), a lack of genetic structure among phenotypes with no reproductive barriers (Chapter 4), river effects on genetic structure of endemic populations (Chapter 5), …

Verbal Estimation Of Peak Dynamic Hand Forces In Experienced And Novice Manual Material Handlers, Amber Phillips

Electronic Theses and Dissertations

This study examined participants' verbally estimated peak dynamic hand forces compared to actual hand forces during various pushing and pulling tasks. Effects of manual material handling (MMH) experience and feedback training on hand force self-reporting were studied. Verbally estimated hand forces were similar across all four groups, despite different amounts of feedback training received and MMH experience. Participants were more accurate verbally estimating pushes than pulls for two-handed tasks, and at low force level for one and two-handed tasks (mean errors =10.2 % MVC and 9.4 % MVC). Verbal estimation differences existed between high and medium forces for two-handed tasks, …

Spy1'S Role In Breast Cell Tumorigenesis, Dorothy C. Myers

Electronic Theses and Dissertations

Spy1A is an essential cell cycle protein, functioning similar to a cyclin, activating the cyclin dependent kinase (CDK) family and enhancing cell growth processes. This body of research confirms that Spy1A protein is tightly regulated during mammary gland development. Utilization of a murine mammary fat pad transplant model demonstrates that ectopic Spy1A expression increases the rate of cell proliferation, leading to precocious mammary gland development and acceleration of breast cell tumorigenesis. Additionally, Spy1A protein was present in the invasive breast cancer cell line, MDA-MB-231, and in human female brain cancers metastasized from primary breast tumors. It was also shown that …

Jacking In Chinook Salmon (Oncorhynchus Tshawytscha ): Environmental And Genotypic Effects On Life History Strategy, William Brent Young

Electronic Theses and Dissertations

Jacking in Chinook salmon (Oncorhynchus tshawytscha), is defined as precocious sexual maturation of males after at least 1 year in sea water, and occurring 1 year prior to females of the same cohort. Substantial evidence supports genetic, environmental, and genetic by environmental effects on precocious maturation in Chinook salmon, however the underlying mechanisms remain unclear.

Passive integrated transponder tagged fish were followed through fresh and salt water growth to the sexual maturation of the jacks. Growth data was recorded to examine the relationship between size/growth effects in freshwater rearing on subsequent precocious sexual maturation of the jacks. No …

Biochemical And Functional Characterization Of A Tetra-Phosphorylation Motif, Catherine Sykes

Electronic Theses and Dissertations

Hierarchical phosphorylation of four Ser/Thr residues orchestrates the ubiquitination and proteasomal degradation of the transcriptional co-activator, β-catenin [16]. To the best of our knowledge, β-catenin is the only known protein with this tetraphosphorylation motif (TPM). However, the sophistication of this scheme prompted our hypothesis that there are other proteins regulated by this TPM.

Herein, we identified two novel TPM-containing proteins, TAZ and KLF7. Characterization of the TAZ and KLF7 TPMs revealed significant similarities and differences with respect to the biochemical role of the β-catenin TPM and demonstrated a functional consequence of their TPMs within the TAZ- and KLF7-mediated inhibition of …

The Greenland Halibut Of Cumberland Sound: Trends In Catch Rates And Preferences In Diet, Susan T. Dennard

Electronic Theses and Dissertations

Inaccessibility and harsh conditions of the Arctic frequently limit research on local fish and ecosystems. Cumberland Sound on southern Baffin Island houses a remote, winter fishery for Greenland halibut (Reinhardtius hippoglossoides) and presented a unique site for evaluating Arctic fish stock trends and feeding behavior from limited data. Relative abundance through time, 1987-2003, of the Greenland halibut stock was modeled hierarchically from catch per unit effort (CPUE) data with multiple fixed effects and location and fisherman as random effects. Month and the North Atlantic Oscillation were important predictors of CPUE. Additionally, fisherman behavior influenced CPUE, breaking the assumption that CPUE …