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Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine Jan 2018

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …


Forensic Markers Of Lampricide Toxicity In Oncorhynchsus Mykiss, Chris White Jan 2018

Forensic Markers Of Lampricide Toxicity In Oncorhynchsus Mykiss, Chris White

Theses and Dissertations (Comprehensive)

The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) has been used for decades to control invasive sea lamprey (Petromyzon marinus) populations in the Great Lakes, normally with little harm to other fish populations. However, due to the nature of lampricide treatments and the chemical properties of TFM, adverse effects to non-target fishes and non-target mortality occasionally occur. However, investigations of non-target mortality can be complex, particularly if fish deaths are not noticed immediately, due to decomposition of the carcasses. The objectives of this thesis were to expose rainbow trout (Oncorhynchsus mykiss) to TFM in order to: (i) identify forensic markers …


Charecterization Of The Innate Immune Response In The Rat Intervertebral Disc At The Tissue And Cellular Level, Matthew Guerreiro Jan 2018

Charecterization Of The Innate Immune Response In The Rat Intervertebral Disc At The Tissue And Cellular Level, Matthew Guerreiro

Theses and Dissertations (Comprehensive)

Low back pain (LBP) affects up to 80% of the global population at some point during their life. The costs associated with LBP are estimated at $100 billion per year, putting significant strains on our healthcare system. As intervertebral disc (IVD) herniation is one of the major causes of LBP we decided to focus on herniation facilitated inflammatory responses, where damage caused by herniation triggers an innate immune response which likely results in pain, inflammation, and recruitment of specialized innate immune cells like macrophages to the affected area. Since the role of the inflammatory response is relatively uncharacterized in the …


Gill Structure & Function In Parasitic And Non-Parasitic Lampreys: The Effects Of Metamorphosis And Freshwater-Seawater Transfer, Julia Sunga Jan 2018

Gill Structure & Function In Parasitic And Non-Parasitic Lampreys: The Effects Of Metamorphosis And Freshwater-Seawater Transfer, Julia Sunga

Theses and Dissertations (Comprehensive)

Lamprey (Petromyzontiformes) are a phylogenetically ancient group of jawless fishes that begin their lives as filter-feeding larvae (ammocoetes) before undergoing a complex metamorphosis into juvenile lamprey that involves major changes to their internal and external body plan. Some parasitic species, such as the sea lamprey (Petromyzon marinus), migrate to sea following metamorphosis, where they use their oral discs and rasping tongue to attach to and ingest vast quantities of blood from fishes. Thus, sea lamprey have to counter the simultaneous challenges of hyposmoregulation in sea water and the generation of large quantities of ammonia due to the …


Molecular Characterization Of The Mummichog (Fundulus Heteroclitus) Ovarian Steroidogenic Pathway And Implications For Exogenous Estrogen Effects During Follicular Development, Thiviya Kanagasabesan Jan 2018

Molecular Characterization Of The Mummichog (Fundulus Heteroclitus) Ovarian Steroidogenic Pathway And Implications For Exogenous Estrogen Effects During Follicular Development, Thiviya Kanagasabesan

Theses and Dissertations (Comprehensive)

This study investigated ovarian development in Fundulus heteroclitus (mummichog), through molecular characterization of key mediators in the ovarian steroidogenic pathway; these included ovarian StAR (steroidogenic acute regulatory protein), cytochrome P450 enzymes, estrogen receptors (ERα, ERβ1 and ERβ2), and gonadotropin receptors (FSHr and LHr); additionally, hepatic vitellogenin (VTG1) and ERs, and brain P450 aromatase (P450arom; CYP19b) were studied. Fish were staged into cortical alveolus, vitellogenic, early mature, late mature, and ovulating stages of maturation; blood (plasma), ovary (tissue and isolated ovarian follicles per stage), liver, and brains were collected. Testosterone (T), 17β-estradiol (E2) and maturation inducing steroid (MIS), measured …


Near-Surface Permafrost Ground Ice Characteristics And Ecological And Physical Drivers Of Transient Layer Ice Content In Discontinuous Permafrost, Jason Paul Jan 2018

Near-Surface Permafrost Ground Ice Characteristics And Ecological And Physical Drivers Of Transient Layer Ice Content In Discontinuous Permafrost, Jason Paul

Theses and Dissertations (Comprehensive)

Accelerated climate warming in northern regions is causing permafrost degradation, leading to the reduction of the areal extent of permafrost. Permafrost is the foundation for many northern ecosystems and communities, so its thaw can have important ecological and societal consequences. Thaw of ice-rich permafrost can cause subsidence of the ground surface proportional to excess ice content. Terrain settlement can cause ponding or damage to infrastructure. Following a surface disturbance that removes much of the vegetation cover, a shift in the ground thermal regime can cause an increase in active layer thickness and rapid thaw of the top portion of permafrost. …


Distribution And Stability Of The Lampricide 3-Trifluoromethyl-4-Nitrophenol (Tfm) In Non-Target Rainbow Trout (Oncorhynchus Mykiss) And White Sucker (Catostomus Commersonii), Darren Foubister Jan 2018

Distribution And Stability Of The Lampricide 3-Trifluoromethyl-4-Nitrophenol (Tfm) In Non-Target Rainbow Trout (Oncorhynchus Mykiss) And White Sucker (Catostomus Commersonii), Darren Foubister

Theses and Dissertations (Comprehensive)

The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is applied to tributaries of the Great Lakes to control invasive sea lampreys (Petromyzon marinus). Although TFM is selectively toxic to larval sea lampreys, non-target mortality can occur during lampricide treatments. It is important to know whether or not TFM played a role in the death of these fishes, and the most direct means to do this is using forensic science principles. The objectives of this study were to: (i) determine the acute toxicity of TFM to the non-target fishes, rainbow trout (Oncorhynchus mykiss) and white sucker (Catostomus commersonii), and how the lampricide is …


Evidence For Extra-Gastric Expression Of The Proton Pump H+/K+ -Atpase In The Gills And Kidney Of The Teleost Oreochromis Niloticus, Ebtesam Barnawi Jan 2018

Evidence For Extra-Gastric Expression Of The Proton Pump H+/K+ -Atpase In The Gills And Kidney Of The Teleost Oreochromis Niloticus, Ebtesam Barnawi

Theses and Dissertations (Comprehensive)

It is well known that stomach acid secretion by oxynticopeptic cells of the gastric mucosa is accomplished by the H+/ K+-ATPase (HKA), which is comprised of the HKα1 (gene: atp4a) and HKβ (gene: atp4b) subunits. However, the role of the HKA in extra-gastric organs such as the gill and kidney is less clear especially in fishes. This pump may contribute to active ion and/or acid-base regulation either through direct ion transport or through secondary transport proteins against unfavorable concentration gradients via the energy derived from ATP hydrolysis. In the present work I have demonstrated …


The Influence Of Water Chemistry And Gill Physiology On The Uptake Of The Lampricide Tfm By Lake Sturgeon (Acipenser Fulvescens), Scott Leslie James Hepditch Jan 2018

The Influence Of Water Chemistry And Gill Physiology On The Uptake Of The Lampricide Tfm By Lake Sturgeon (Acipenser Fulvescens), Scott Leslie James Hepditch

Theses and Dissertations (Comprehensive)

Application of 3-trifluoromethyl-4-nitrophenol (TFM) to control invasive sea lamprey (Petromyzon marinus) within the Laurentian Great Lakes seldom causes non-target mortality. However, under certain conditions, TFM can harm species such as the lake sturgeon (Acipenser fulvescens). Lake sturgeon less than 100mm in length are particularly vulnerable to TFM-induced mortality, and are more sensitive to TFM toxicity with increasing water alkalinity as compared to sea lamprey. The objectives of this study were to evaluate the influence of pH and alkalinity on the uptake of TFM by juvenile sturgeon using radio-labeled TFM (14C-TFM). An additional objective was …


The Influence Of Physiological And Abiotic Factors On The Sensitivity Of The Sea Lamprey (Petromyzon Marinus) To The Lampricide 3-Trifluoromethyl-4-Nitrophenol (Tfm), Alexandra Muhametsafina Jan 2018

The Influence Of Physiological And Abiotic Factors On The Sensitivity Of The Sea Lamprey (Petromyzon Marinus) To The Lampricide 3-Trifluoromethyl-4-Nitrophenol (Tfm), Alexandra Muhametsafina

Theses and Dissertations (Comprehensive)

Invasive sea lamprey (Petromyzon marinus) in the Great Lakes are controlled using the pesticide (lampricide) 3-trifluoromethyl-4-nitrophenol (TFM), which is applied to nursery streams containing larval lamprey. The toxicity of TFM to lamprey is affected by various environmental and physiological factors, which can lead to residual lamprey that survive TFM treatment. The goal of this study was to investigate how abiotic (season and temperature) factors interacted with physiological parameters (whole body and tissue energy reserves) to influence TFM sensitivity in sea lamprey. Toxicity tests were conducted at different times of the year (spring, early and late summer, fall) and …


An Assessment Of The Plant And Mycorrhizal Community At Steeves Lake Shoreline, Colomac Mine, Nwt, Rebekah Hamp, Dr. Kevin Stevens Jan 2018

An Assessment Of The Plant And Mycorrhizal Community At Steeves Lake Shoreline, Colomac Mine, Nwt, Rebekah Hamp, Dr. Kevin Stevens

Theses and Dissertations (Comprehensive)

This study focused on the environmental impacts of mining and potential techniques to mitigate them. The goals of this study were to (1) Quantify vegetation and fungal colonization at a remediated mine site in northern Canada, and to determine if there were effects from petroleum hydrocarbon contamination, (2) Determine the response of northern plants inoculated with mycorrhizal fungi to diesel contamination. Mycorrhizal colonization was observed in field collected roots and trends in colonization and vegetation cover suggested that these communities were no longer impacted by residual contamination. Mean hyphal colonization of Elymus trachycaulus roots collected over two years was 47.3±3.8% …