Graduate Theses & Dissertations

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Influence of nitrogen and sulfur on cadmium tolerance in Euglena gracilis
Heavy metal pollution threatens human and ecosystem health. E. gracilis was investigated for its potential use in bioremediation due to its tolerance for heavy metals and ability to sequester them from the environment. E. gracilis can remove metals by producing metal binding compounds enriched in sulfur and nitrogen. In this thesis, E. gracilis cultures that were pretreated with elevated levels of sulfur or nitrogen had increased tolerance to CdCl2 compared to non-pretreated cultures. RNA-sequencing revealed that both pretreatments led to transcript level changes and that exposure to CdCl2 led to further transcript level changes. Gene ontology (GO) enrichment analysis reflected changes in nitrogen and sulfur metabolism as well as physiological processes related to metal binding. The data from this thesis revealed important transcription level changes that occur when E. gracilis is challenged with CdCl2 and helps us understand how organisms adapt to heavy metal pollution in the environment. Author Keywords: bioremediation, Cadmium, Euglena gracilis, GO-enrichment, metal-binding, RNA-Sequencing
Heteronormativity in Virtual World Design
The purpose of this research is to highlight the limitations and opportunities for playful expression of gender identity in character creation systems of virtual worlds, and how these might work to reinforce, or disrupt, the heteronormative imperative. The primary sites considered in this analysis are the video game World of Warcraft and the live action role-playing game Amtgard. I provide evidence that while the World of Warcraft’s character creation system is sexist and works to reinforce heteronormative ideology, Amtgard’s relatively ambiguous design provides opportunity for disruption of these norms. Participant research with Amtgard players demonstrates actual instances of Amtgard’s more flexible character creation system being utilized in expression and exploration of gender identity which resists the heteronormative imperative. Based on this, I call on game developers to reject designs which necessitate selection of gender from within the traditional binary and embrace more ambiguous design in development of character creation systems. Author Keywords: Avatars, Game Design, Games, Gender, Identity, Virtual Worlds
Functional Variation within Middle Paleolithic Ground Stone Tools
In the southern Levant, ground stone tools (GST) provide insight into early plant food exploitation, butchery, and cognition. Outside of these examples, GST evidence is scarce, particularly for the Middle Paleolithic. An extensive assemblage of GST recovered from Nesher Ramla, an open-air hunting camp in Israel, presents the unique opportunity to study the role of GST within Middle Paleolithic behaviour. Use-wear and residue analysis, together with replication experiments are employed to investigate GST function within a specific period of site use by focusing on GST from the Upper Sequence (Units I-II) which reflects a trend of decreasing site-use intensity. The results indicate that GST were employed for bone breaking and knapping during the final phases of occupation while comparison with Unit V suggests longer occupations involved more diverse and extensive use of GST. GST at open-air sites are also proposed to represent a strategy for intensive exploitation of location-specific resources. Author Keywords: Ground Stone Tools, Hammerstones, Middle Paleolithic, Residue Analysis, southern Levant, Use-Wear Analysis
Gene flow directionality and functional genetic variation among Ontario, Canada Ursus americanus populations.
Rapidly changing landscapes introduce challenges for wildlife management, particularly for large mammal populations with long generation times and extensive spatial requirements. Understanding how these populations interact with heterogeneous landscapes aids in predicting responses to further environmental change. In this thesis, I profile American black bears using microsatellite loci and pooled whole-genome sequencing. These data characterize gene flow directionality and functional genetic variation to understand patterns of dispersal and local adaptation; processes key to understanding vulnerability to environmental change. I show dispersal is positively density-dependent, male biased, and influenced by food productivity gradients suggestive of source-sink dynamics. Genomic comparison of bears inhabiting different climate and forest zones identified variation in genes related to the cellular response to starvation and cold. My thesis demonstrates source-sink dynamics and local adaption in black bears. Population management must balance dispersal to sustain declining populations against the risk of maladaptation under future scenarios of environmental change. Author Keywords: American black bear, Dispersal, Functional Genetic Variation, Gene Flow Directionality, Genomics, Local Adaptation
Ê-NITONAHK MIYO-PIMÂTISIWIN (SEEKING THE GOOD LIFE) THROUGH INDIGENOUS DANCE
This thesis is about the ways in which Indigenous dance serves as a social determinant of Indigenous health and well-being. Utilizing both contemporary and traditional versions of the Medicine Wheel for the framework, analysis and organization of the thesis allows for a holistic perspective which includes the spiritual, physical, emotional and mental aspects. The importance of Indigenous dance for Indigenous health and well-being is confirmed through: existing literature; interviews with Indigenous choreographers, dancers, theatre artists, and performers; Indigenous exponents of the forms; and Indigenous Elders. In order to contextualize current practices of Indigenous dance, the history of Indigenous dance in relation to colonization is presented. The research and experiences of co-researchers show the need for Indigenous dance and culture to be supported as a social determinant of health and well-being. Author Keywords:
Exploring the Role of Natural Antisense Transcripts in the Stress Response of Ustilago maydis
Fungal pathogens adapt to environmental changes faster than their hosts, due in part to their adaptive mechanisms exhibited in response to stress. Ustilago maydis was used to investigate potential natural antisense transcript (NAT) RNA-mediated mechanisms that enhance fungal adaptation to stress. Of the 349 NATs conserved amongst U. maydis and two related smut fungi, five NATs were identified as having altered transcript levels in response to multiple stress conditions. Subsequently, antisense transcript expression vectors were created for select NATs and transformed into U. maydis haploid cells. When exposed to stress conditions, two antisense expressing mutant strains exhibited alterations in growth. RT-qPCR analysis of mRNA complementary to expressed NATs revealed no significant change in mRNA levels, which suggests NAT expression may influence stress response through dsRNA formation or other RNA mediated mechanisms. These results establish a basis for further investigations into the connection between NATs and the stress response of fungi. Author Keywords: natural antisense transcripts, non-coding RNAs, stress response, Ustilago maydis
The Relations Between Identity Developmental Processes, Study Habits, and Academic Performance
Adolescence is a time when young people focus their attention on setting and pursuing long-term goals. Contemporary approaches of identity development focus on three pivotal processes underlying the identity formation process and the maintenance of one’s identity (e.g., core values, etc.). These processes are commitment (commitments to a goal), in-depth exploration (exploration of choices and options), and reconsideration of commitment (feelings of uncertainty about current commitments). The primary purpose of the current study was to examine the relations between identity processes, study habits, and academic performance in 45 female undergraduate students (M age = 21.00). Utilizing a self-report measure, findings suggested a significant positive relation between educational and relational commitment, as well as reconsideration of commitments in the educational domain and reconsideration of commitments in the relational domain. In terms of identity processes and grades, a regression analysis revealed that educational reconsideration of commitments predicted academic performance. Further, for those employing poor study habit skills, educational reconsideration of commitment predicted academic performance. The present study offers insight on the importance of assessing adolescent’s uncertainty of educational and relational commitments, while also highlighting the protective factor of maintaining good study habit strategies. Author Keywords: academic performance, adolescence, educational, identity, relational, study habits
SARS-CoV-2 Protein-based Detection Using Localized Surface Plasmon Resonance
During the COVID-19 pandemic, nucleic acid and antibody-based testing methods were heavily relied upon, but can be costly, time-consuming and exhibit high false -negative and -positive rates. Thus, alternative strategies are needed. Viral antigens such as the SARS-CoV-2 spike (S) glycoprotein are critical in the function of the virus and useful as diagnostic biomarkers for viral infections. For biosensing applications, aptamers are suitable high-affinity and cost-effective binding partners for their specific targets. Using localized surface plasmon resonance (LSPR), real-time, rapid acquisition of results can be achieved, essential for improving the efficacy of a sensor. Herein, LSPR aptamer sensors were fabricated for the detection of the SARS-CoV-2 protein. Data indicate that the best performing aptasensor was the streptavidin-biotin sensor, while the current gold aptasensor exhibited lower sensitivity and the fabrication of the carboxyl aptasensor was unsuccessful. The S1 aptamer selectively bound the S1 protein with high binding affinity. Excellent shelf-life stability, reusability, and high recovery in complex matrices was also maintained. Additionally, a receptor binding domain (RBD) functionalized sensor was fabricated to examine the interactions with angiotensin converting enzyme 2 (ACE2), for future assessment of inhibitors used in drug therapies. Overall, LSPR has been demonstrated as a viable tool for measuring SARS-CoV-2 related aptamer-protein and protein-protein interactions, and this strategy may be applied to other viral or non-viral antigen targets. Author Keywords: Antigen-based Detection, Coronavirus, COVID-19, Inhibition, Localized Surface Plasmon Resonance, SARS-CoV-2
What Happens in Childhood, Does Not Stay in Childhood
Researchers have found associations between attachment, childhood adversity, and posttraumatic stress symptoms; however, the underlying mechanisms between these variables remains unknown. The present study explored the moderating effects of childhood adversity on the relationship between adult attachment and posttraumatic stress symptoms in two samples. In total, 533 undergraduate students and 357 individuals recruited from online communities completed measures of childhood adversity, adult attachment, and posttraumatic stress symptoms. Hierarchical regression analyses were used to test the moderating effect on childhood adversity. One-way ANOVA post hoc analyses were run to assess mean differences of attachment and posttraumatic stress across five childhood adversity groups. The results suggested that attachment and childhood adversity do predict posttraumatic stress symptoms; however, there was no significant moderating effect of adversity found. The post hoc analyses revealed significant mean differences for secure attachment, avoidant attachment, and posttraumatic stress symptoms. The findings suggest that attachment and childhood adversity are significantly associated with posttraumatic stress symptoms. Author Keywords: adult attachment, childhood adversity, posttraumatic stress symptoms, trauma
Land Cover Effects on Hydrologic Regime within Mixed Land Use Watersheds of East-Central Ontario
Land cover change has the potential to alter the hydrologic regime from its natural state. Southern Ontario contains the largest and fastest growing urban population in Canada as well as the majority of prime (Class I) agricultural land. Expansions in urban cover at the expense of agricultural land and resultant ‘agricultural intensification’, including expansion of tile drainage, have unknown effects on watershed hydrology. To investigate this, several streams with a range of landcovers and physiographic characteristics were monitored for two years to compare differences of flashiness and variability of streamflow using several hydrologic metrics. Urban watersheds were usually the flashiest while agriculture had moderate flashiness and natural watersheds were the least flashy across all seasons, signifying that landcover effects were consistent across seasons. Tile drainage increased stream flashiness during wet periods, but minimized the stream response to an extreme rain event in the summer, perhaps due to increases in soil moisture storage. A sixty-year flow analysis showed that flashiness and streamflow increased (p < 0.05) above a development threshold of ~10% of watershed area. Flashiness was also greater in wetter years suggesting that climate shifts may enhance stream variability in developed watersheds. Author Keywords: Agriculture, Flashiness, Hydrologic Metrics, Hydrologic Regime, Landcover Change, Urban
Does boredom lead to ego-depletion? Examining the association between boredom and ego-depletion
Ego-depletion refers to the observation that using self-control at Time 1 (T1) in the sequential-task paradigm leads to worse self-control at Time 2 (T2; Baumeister et al., 1998). Self-control is often manipulated by varying the difficulty of the task used at T1. Recently, Wolff and colleagues (2020) suggested that failures to replicate the ego-depletion phenomenon may arise because simple tasks may be boring, therefore requiring self-control to maintain attention on the task. Three experiments (Experiment 1, N=60; Experiment 2, N=61; Experiment 3, N=59) are reported that examined whether boredom at T1 predicted self-control at T2. A simple Go/No-Go task was used at T1. The ratio of Go to No-Go trials was changed across experiments to explore how the properties of the boring task impacted the association between boredom and self-control. When responding was frequent, increased boredom at T1 was associated with fewer anagrams correctly solved (Experiment 1 and 3), and more self-reported fatigue at T2 (Experiment 1), consistent with boredom leading to ego-depletion. However, when responding was infrequent (Experiment 2), increased boredom at T1 was associated with more correctly solved anagrams at T2, suggesting that the properties of a boring task change the psychological outcome that task has on self-control. Author Keywords: attention, boredom, ego-depletion, executive function, self-control
Oil is Thicker than Justice
This thesis provides a comprehensive overview of the extractive industry operating out of the Alberta tar sands region to determine how environmental violence is enacted against Indigenous women, girls, and queer or Two-Spirit peoples in the Lubicon Lake Cree Nation and beyond. Through an analysis of existing literature in the field, a case study on the Lubicon Lake Nation and a policy analysis of the Calls for Justice from the Final Report of the National Inquiry into Missing and Murdered Indigenous Women, this thesis draws links between industrialization, capitalism, the heteropatriarchy, and colonialism. Finally, this thesis offers a pathway to resurgence, through the subversion of colonial gender and sexual norms, and collective action to reclaim Indigenous territory as an alternative to state-sponsored solutions and policies. Author Keywords: Colonial heteropatriarchy, Environmental violence, Land Back, Lubicon Lake, Tar sands, Violence against Indigenous women

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