Life Sciences Commons^™

Analysis Of Iophenoxic Acid Analogues In Small Indian Mongoose (Herpestes Auropunctatus) Sera For Use As An Oral Rabies Vaccination Biological Marker, Are R. Berentsen, Robert T. Sugihara, Cynthia G. Payne, Israel Leinbach, Steven F. Volker, Ad Vos, Steffen Ortmann, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases reported annually. The control of RABV circulation in wildlife reservoirs is typically accomplished by a strategy of oral rabies vaccination (ORV). Currently no wildlife ORV program exists in Puerto Rico. Research into oral rabies vaccines and various bait types for mongooses has been conducted with promising results. Monitoring the success of ORV relies on estimating bait uptake by target species, which typically involves evaluating a change in RABV neutralizing antibodies (RVNA) post vaccination. This …

Trail Cameras Are A Key Monitoring Tool For Determining Target And Non-Target Bait-Take During Rodent Removal Operations: Evidence From Desecheo Island Rat Eradication, Aaron B. Shiels, D. Will, C. Figuerola-Hernández, K.J. Swinnerton, S. Silander, C. Samra, G.W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

Efforts to remove invasive rodents (e.g. Rattus spp. and Mus musculus) from islands often use toxicant-laced baits containing the anticoagulants brodifacoum or diphacinone. Rodenticide baits are generally delivered through aerialor hand-broadcast, or in bait stations. These baits are not rodent-specific and are subject to non-target consumption or secondary exposure (e.g. an individual preying upon another individual that has consumed bait). During rodenticide applications, it is generally unknown which animals are visiting and consuming bait; and to quantify this, we recommend using trail cameras (e.g. Reconyx^tm motion-activated infra-red) positioned to monitor individual bait pellets. To demonstrate the importance and effectiveness …

Adventures In Time And Space: What Shapes Behavioural Decisions In Drosophila Melanogaster?, Heather Malek, Tristan Af Long Dr.

Theses and Dissertations (Comprehensive)

Variation in behaviour can be observed both between individuals, based on their condition and experience as well as between populations due to sources of heterogeneity in the environment. These behavioural differences have evolved as a result of natural and sexual selection where different strategies may be favoured depending on the costs and benefits associated with those behaviours. In this thesis I examine two sources of heterogeneity within the environment and their behavioural consequences: how spatial complexity mediates sexual selection over time, and how inter and intraspecific signals and individual condition influence social oviposition behaviour. By increasing spatial complexity, we were …

Functional Characterization Of O-Acetyltransferase Wssi: Role In Bacterial Cellulose Acetylation Of Achromobacter Insuavis And Pseudomonas Fluorescens, Alysha Burnett

Theses and Dissertations (Comprehensive)

Cellulose biofilms consist of a community of bacterial cells encased in a self-produced matrix of polymers (e.g. exopolysaccharides, such as cellulose) that facilitate a firm adherence to surfaces. The acetylation (addition of an acetyl group on carbohydrates) is crucial in virulence; thereby in some cases allowing opportunistic bacteria to cause harmful diseases. Pertaining to this research, the wrinkly spreader (WS) genotype of Pseudomonas fluorescens colonizes the air-liquid interface on food, water sources and human tissue to form a robust biofilm with the ability to spread across surfaces. The composition of this biofilm largely consists of bacterial cellulose polymers …

Structural And Functional Analysis Of Three Upregulated Gene Products, Tde0626, Tde1701, And Tde2714 From Treponema Denticola During Biofilm Formation, Jonah Nechacov

Theses and Dissertations (Comprehensive)

The progression of human chronic periodontitis within periodontal disease has been often linked to the presence of key pathogens, such as the presence of Treponema denticola, a late colonizer found in the deepening pockets of the gingival sulcus. This pathogen, as well as its associates Porphyromonas gingivalis and Tannerella forsythia, are classified as the ‘red complex’ and exist in a mixed biofilm during infection. It is within this biofilm state that previous transcriptomic analysis revealed a total of 126 genes that had an increase in their expression by 1.5-fold or greater in T. denticola. Three of these …

The Impacts Of Gold Mining On Vegetation And Mycorrhizal Colonization In Northern Canada, Sarah Mediouni

Theses and Dissertations (Comprehensive)

Gold mining is an important part of economic development in Northern Canada. A large portion of the gold that is found in the North is contained within arsenopyrite ores, therefore, arsenic contamination is of special concern. Little is known regarding the impacts of arsenic on plants and mycorrhizae in Northern Ecosystems. Arsenic has been shown to negatively impact plant growth and seed germination in some temperate species, while others are tolerant and can accumulate arsenic concentrations over 1000 mg/kg. In temperate regions, arbuscular mycorrhiza can accelerate the remediation process in gold mines by supporting plant growth in poor soil conditions …

Characterization Of Wssf; A Putative Acetyltransferase From Achromobacter Insuavis And Pseudomonas Fluorescens, Cody Reese

Theses and Dissertations (Comprehensive)

Biofilms are a survival mechanism commonly employed by communities of bacteria for adherence and protection. Bacteria produce a matrix of polymers (e.g. exopolysaccharides, such as cellulose) that allow them to exert control on their local environment. In the case of cellulose biofilms, acetylation (addition of acetate on carbohydrates) is paramount for polymer integrity and in some cases virulence. For this research, the wrinkly spreader (WS) genotype of the emergent human pathogen Achromobacter insuavis facilitates infections of the eyes of contact lens wearers and the lungs of Cystic Fibrosis patients (CF). Chronic infections have created a growing concern for the protective …

Spinal Motor Neuron Excitability During Fatigue, Nathalie Cecire

Theses and Dissertations (Comprehensive)

Fatigue during sustained or repeated muscular contractions can be from contractile failure within the muscle or reduced excitability in the supraspinal and spinal motor neurons. However, spinal motor neurons can also compensate for fatigue. We speculate that one way the spinal motor neuron compensates for fatigue is through an increase in excitability via the activation of persistent inward currents (PIC). In other conditions where there is a reduction in descending drive, such as during spinal cord injury and aging, there are adaptions of the spinal motor neurons to have elevated PIC amplitudes or towards a greater prevalence of PIC, respectively. …

Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh

Theses and Dissertations (Comprehensive)

The North American Great Plains is home to thousands of closed-basin lakes that are sensitive to changes in hydrology. Climate change models predict increased aridity in this region over the coming century, which is expected to lead to higher salinity levels in many freshwater lakes. Increases in salinity levels may impact zooplankton communities, as laboratory experiments show that many freshwater species have a low tolerance for elevated salinity levels, and field data demonstrate that salinity is the primary factor structuring aquatic communities on the Great Plains. Changes to zooplankton communities could lead to a trophic cascade based on their important …

Going Back To The Soil: An Integrated Approach To Farming., Renée V. Christie

Theses and Dissertations (Comprehensive)

Agricultural productivity is often constrained by nutrient availability; as such, copious amounts of synthetic fertilizers are applied to maintain productivity. However, the intensive use of synthetic fertilizers has reduced the capacity of the soil to carry out crucial roles such as nutrient cycling because of shifts in the microbial community composition and structure. In addition, much of the applied synthetic fertilizers become lost to the environment through run-off, which contributes to soil degradation. With the increasing demand on agricultural systems to provide food and fibre and the adverse impacts of agricultural production on the soil resource, amendments that support soil …

Characterization Of The Microbial Phosphonate-Activating Pntc Enzymes, Kyle Rice

Theses and Dissertations (Comprehensive)

New strategies are urgently needed to combat infectious diseases in an era of rising antibiotic resistance. Furthermore, an emerging appreciation for the human microbiome’s role in maintaining health motivates discovery of species-specific antibiotics that minimally disrupt our native bacterial communities. Small molecule modifications to bacterial cell surfaces represent a potentially rich source of new targets for next generation antibiotics, as these molecules mediate virulence and evasion of the host immune response. Phosphocholine (PCho) is a rare cell surface modification that contributes to virulence, and modifications with phosphonates like 2-aminoethylphosphonate (AEP) are even more unusual and therefore provide opportunities for species- …

Expression Of Alternative Oxidase In The Copepod T. Californicus When Exposed To Environmental Stressors, Carly Tward

Theses and Dissertations (Comprehensive)

In addition to the typical electron transport system in animal mitochondria responsible for oxidative phosphorylation, some species possess an alternative oxidase (AOX) pathway, which causes electrons to bypass proton pumping complexes. Although AOX appears to be energetically wasteful, studies have revealed its wide taxonomic distribution, and indicate it plays a role in environmental stress tolerance. AOX discovery in animals is recent, and further research into its expression, regulation, and physiological role has been impeded by the lack of an experimental model organism. DNA database searches using bioinformatics revealed an AOX sequence present in the arthropod Tigriopus californicus. Multiple sequence …

Riparian Zone Soil Microbial Community Dynamics: Interactions With Nutrient Loadings, James Bannister

Theses and Dissertations (Comprehensive)

Riparian zones are a type of wetland described as the interface between land and a body of water such as a river or stream. Riparian zones are effective buffers against anthropogenic pollutants and nutrient loads from non-point sources that can greatly diminish water quality. Riparian zones can host a variety of plant species and associated microbial communities. The combined biological processes of plants, bacteria, and arbuscular mycorrhizal fungi (AMF) are key to nutrient cycling and nutrient removal in riparian zones. As such, understanding the factors that influence them is critical for watershed management. This research is targeted at obtaining a …

Potential Impact Of Northern Resource Development On Aquatic Biota: Toxicity Of Chromium And Rare Earth Element Processing Reagent, So Yeon Choi

Theses and Dissertations (Comprehensive)

Chromite and rare earth element development was identified in the 2015 Canadian Federal budget as a significant opportunity, however, key data gaps exist regarding the environmental concerns related to these resource developments. Chromium is essential in the production of stainless steel, and no suitable substitute is known. Rare earth elements (REEs) are a series of metals that are composed of 15 lanthanides, as well as scandium and yttrium. Uses for REEs range from electronic devices (i.e. cell phones, computers, televisions) to magnets and controlling nuclear reactors. While commercial production of REEs signify a great economic opportunity for Canada, key data …

The Effect Of Loading Rate On Annulus Fibrosus Strength Following Endplate Fracture, John Mcmorran

Theses and Dissertations (Comprehensive)

Low back pain is the most prevalent cause of chronic pain for North Americans, and its correlation with endplate damage, and deficient mechanical properties in the annulus fibrosus (AF) makes this injury particularly concerning. To date, biomechanical alterations in the AF following endplate fracture have not been well described. Owing to the AF’s collagenous composition, and the intrinsic biomechanics of intervertebral discs (IVDs) during compression, it was hypothesized that the mechanical properties of AF specimens would show rate-dependent alterations in their tensile and adhesive strengths following endplate fracture. The purpose of the present study was to quantify the mechanical properties …

Happy Or Hangry Families: Does Kinship Mediate Cooperation And Cannibalism In Drosophila Melanogaster Larvae?, Lucas Khodaei

Theses and Dissertations (Comprehensive)

The fruit fly Drosophila melanogaster has a long history as a research model for studies on behaviour and group dynamics. When individuals are grouped in an environment and resources decrease, then they may behave co-operatively with one another or antagonistically compete. Hamilton’s Law states that if the benefit of helping a related individual out-weighs the cost to its direct fitness, then the individual’s indirect fitness will increase when they help their kin compared to helping an unrelated stranger. Yet it is unknown whether kinship mediates larval behaviour to encourage co-operation and/or lessen antagonistic behaviours between consanguineous individuals. In this thesis …

Diversity And Evolution Of Seeds In Cuscuta (Dodders, Convolvulaceae): Morphology And Structure, Magdalena Olszewski

Theses and Dissertations (Comprehensive)

Cuscuta is a genus of nearly 200 obligate stem parasites with a nearly cosmopolitan distribution and considerable agricultural and ecological significance. Dodder seeds are considered “unspecialized”, with no morphological adaptations towards particular dispersal vectors; however, the seed coat anatomy has recently suggested an adaptation to endozoochory. This is the first attempt to provide a genus-wide overview of the diversity in morphology and anatomy of Cuscuta seeds, together with an assessment of the water gap and exploration of various form-function relationships. I surveyed 104 species belonging to all four Cuscuta subgenera. Seeds of the species of the first infrageneric dodder …

Characterization Of The Red Complex Bacterial Biofilm, Alena Pratasouskaya

Theses and Dissertations (Comprehensive)

Commonly associated with severe inflammation and destruction of the tooth-supporting tissue is bacterial consortia Treponema denticola, Tannerella forsythia, and Porphyromonas gingivalis, collectively referred to as the red complex. The red complex uses the common bacterial strategy of producing and embedding itself in extracellular polymeric substance, which contributes to the recalcitrance of periodontitis and was therefore of interest in this study. The red complex static cultures were grown in combination with different chemicals in order to establish what changes accompany these chemical challenges. This research established that extracellular polymeric substance carbohydrate yields increased with time. Interestingly, carbohydrate composition …

The Task At Hand: Fatigue-Associated Changes To Corticospinal Excitability During Writing, Kezia Cinelli

Theses and Dissertations (Comprehensive)

Corticospinal excitability as measured via transcranial magnetic stimulation (TMS) is highly dependent on the task being performed at the time of stimulation. As such, this study sought out to measure corticospinal excitability during the relevant, daily task of writing and compare it to the conventional abduction task often utilized. We used single-pulse motor evoked potentials (MEPs) to provide a measure of corticospinal excitability and cortical silent period (CSP) duration, and paired-pulse conditioned MEPs to assess short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) recorded from the right first dorsal interosseous (FDI) of 19 participants on two randomized and counter-balanced days. …

Characterizing The Cellulose-Modifying Enzyme Bcsg From Escherichia Coli, Alexander Anderson, Joel T. Weadge

Theses and Dissertations (Comprehensive)

Microbial biofilms are communities of microorganisms that exhibit co-operative behaviour, producing a matrix of exopolysaccharide that enmeshes the community. The well-studied human pathogens Escherichia coli and Salmonella entericaproduce a biofilm matrix comprised chiefly of the biopolymer cellulose, along with amyloid protein fibers termed curli. This biofilm matrix confers surface adherence and acts as a protective barrier to disinfectants, antimicrobials, environmental stressors, and host immune responses. Pertaining to this research, the bcsEFG operon, conserved in the Enterobacteriaceae, encodes an inner membrane-spanning complex responsible for the addition of a phosphoethanolamine (pEtN) modification to microbial cellulose, essential for extracellular matrix assembly and …

Exploring Psychological Readiness To Return To Sport After Injury, Scott Donald

Theses and Dissertations (Comprehensive)

Athletes are often cleared to return to sport with little emphasis on psychological readiness in relation to physical readiness. This is important because athletes who are not psychologically ready to return to sport (RTS), despite being physically cleared, may lack motivation to compete and lack confidence in their abilities (Podlog, Banham, Wadey, & Hannon, 2015), drop out of sport, fear re-injury (Ardern et al., 2014), worry about future performance (Podlog & Eklund, 2006), experience anxiety and feel depressed (Tracey, 2003) or incur further injury (McCullough et al., 2012). Remarkably, there is no definition of psychological readiness consistently used in the …

Physical Fatigue Negatively Affects Decision-Making During A Closing-Gap Aperture Crossing Task When Using Joystick-Controlled Locomotion, Natalie Snyder

Theses and Dissertations (Comprehensive)

Goal-direct locomotion is made possible through the integration of sensory input from the visual, vestibular, and somatosensory system. However, changes in collision avoidance behaviours and action capabilities (i.e., affordances) may occur when a sensory conflict is introduced (i.e., via incongruent input from a sensory system). Further, changes to the person (such as physical fatigue) may have negative implications on the cognitive abilities of an individual following physically fatiguing exercise. This in turn could affect an individual’s ability to avoid collisions with objects or other individuals in their environment. Thus, the objective of this thesis was to explore how physical fatigue …

Factors Influencing Zooplankton Communities In Small Arctic Lakes, Northwest Territories, Jasmina Vucic

Theses and Dissertations (Comprehensive)

The Canadian Arctic has been warming at an unprecedented rate, causing significant changes to the environment. At the same time, continued development in the north has increased the demand for gravel extraction used to construct and maintain infrastructure such as highways. The development of roadways and gradual loss of permafrost in Canada’s north has led to changes in water quality, including increased calcium, conductivity, and nutrients. In addition, gravel extraction has led to the formation of artificial gravel pit lakes. Research has yet to determine how physical and chemical changes associated with development and permafrost thaw might impact zooplankton, and …

Context Is Everything: An Investigation Of Spanish River Carbonatite And Its Effects On Soil-Plant-Microorganism Systems, James Mc Jones

Theses and Dissertations (Comprehensive)

With growing concerns about agricultural sustainability and food security, the use of rock fertilizers and agrominerals is receiving renewed interest. A wide variety of geological resources have been proposed as crop nutrient sources, with silicate rocks the predominant focus. Carbonatite rocks are known to weather more readily than silicate rocks; yet, they have received relatively little attention as it is thought their high Ca and Mg contents hinder effective nutrient release. However, there is strong evidence that the nutrients within carbonatite rocks are easily accessible to plants, and that these rocks have noticable effects on crop plant growth. Here I …

Competition Or Facilitation: Examination Of Interactions Between Endangered Sida Hermaphrodita And Invasive Phragmites Australis, Samantha N. Mulholland

Theses and Dissertations (Comprehensive)

Virginia Mallow (Sida hermaphrodita) is a perennial herb of the Malvaceae family that is native to riparian habitats in northeastern North America. Throughout most of its geographical distribution however, it is considered threatened and only two populations are known from Canada. The biology and ecology of S. hermaphrodita are still poorly understood and although few studies have been performed to determine the factors that contribute to the species rarity, it is considered threatened potentially due to the loss of habitat caused by exotic European Common reed (Phragmites australis subsp. australis) invasion. Allelopathic and phytotoxic conditioning of …

Incidence Of Responders Vs Non-Responders With Sprint Interval Training, Kyle Schulhauser

Theses and Dissertations (Comprehensive)

The current study examined the incidence of non-response to a traditional 30:240 s sprint interval training (SIT) protocol, as well as for 2 modified SIT protocols of 15:120 s, and 5:40 s over 4 wk of training in 84 recreationally active males and females (52m, 32f). Pre- and post- testing measures included: aerobic capacity (V̇O_2max), aerobic performance (5-km time trial), and anaerobic capacity (30 s sprint). Non-response was determined using 2x typical error for each variable. Chi square analysis indicated a significant difference (P = 0.032) in the frequency of non-responders for aerobic performance where the 30:240 group …

Investigating The Antiviral Effects Of Vig-3 From Rainbow Trout, Shanee Herrington-Krause

Theses and Dissertations (Comprehensive)

Rainbow trout is the most farmed fish in Ontario, and thus is economically important to the province. Despite this, there is a lack of understanding regarding fish innate immunity, specifically with regards to interferon-stimulated genes (ISGs) and their antiviral effector functions. ISGs are the workhorses of the innate antiviral response, operating together to limit each step of virus replication. The Viral Hemorrhagic Septicemia Virus (VHSV) induced gene (Vig)-3 is a newly identified ISG within many fish species and is homologous to ISG-15 in mammals. It is a small ubiquitin-like protein inducible by type I interferon (IFN-I), and is suggested to …

Expression, Purification, Functional Characterization And Crystallization Of Three Porphyromonas Gingivalis Gene Products, Katarina Mandic

Theses and Dissertations (Comprehensive)

Dental biofilms are coupled polymicrobial aggregates that have attached to solid surfaces in the oral cavity. These collections of microorganisms are known to cause periodontal diseases that commence as localized inflammation of the gingiva and if untreated, eventually lead to irreversible alveolar bone resorption and tooth loss. Porphyromonas gingivalis is one of three periodontal pathogens that make up the “Red Complex”; a bacterial consortium responsible for the production of polysaccharide-rich biofilms that are essential to the inception and progression of periodontal disease. The dysbiosis and destructive inflammation caused by these organisms propel a self-sustained feed-forward loop that perpetuates periodontal disease. …

Environmental Factors Associated With Benthic Macroinvertebrate Communities In Arctic Lakes, Northwest Territories, Rachel Cohen

Theses and Dissertations (Comprehensive)

Lake water quality and the macroinvertebrate communities in Arctic regions are threatened by increased development and climate change. In order to understand how macroinvertebrate communities may respond to their changing environment, I performed a biological and water quality survey of 46 Arctic lakes located in the Gwich’in Settlement Area and the Inuvialuit Settlement Region of the Northwest Territories. Using these survey data, I performed two interrelated studies that asked: 1) how artificial pit lakes associated with gravel extraction for road development compared with natural lakes in terms of their water quality, morphometry, and macroinvertebrate communities; and 2) how water quality …

Halogenated Flame Retardants And Organophosphate Esters In The Air Of Electronic Waste Recycling Facilities: Evidence Of High Concentrations And Multiple Exposures, Sabrina Gravel, Jérôme Lavoué, Bouchra Bakhiyi, Miriam L. Diamond, Liisa M. Jantunen, Jacques Lavoie, Brigitte Roberge, Marc-André Verner, Joseph Zayed, France Labrèche

Études primaires

Background

In response to a worldwide increase in production of electronic waste, the e-recycling industry is rapidly rowing. E-recycling workers are exposed to many potentially toxic contaminants, among which flame retardants (FRs), mainly suspected of being endocrine disruptors, are thought to be the most prevalent.

Objective

To conduct an exposure assessment of four chemical groups of FRs in Canadian e-recycling facilities, and to identify the main cofactors of exposure.

Methods

Personal air samples were collected over a workday for 85 workers in six e-recycling facilities, grouped into three facility sizes, and for 15 workers in control commercial waste facilities. Total …