Integrative Biology Commons^™

Sexual Di(Et)Morphism: Using Experimental Evolution To Test Whether Resource Partitioning Promotes Divergence Of The Sexes In Drosophila Melanogaster, Owen A. Jamieson

Theses and Dissertations (Comprehensive)

Sexual dimorphism has been a long-studied phenomenon in the field of evolutionary biology. Usually, these differences in morphology, physiology and/or behaviour between the sexes are studied through the parsimonious lens of sexual selection. However, there are natural history cases where this lens does not seem applicable. Some species show sex specific morphological traits whose presence may not be due to a direct benefit to reproduction, but a difference in how each sex interacts with the environment and differing selective pressures from the environment on either sex. Darwin even brought up examples of this kind of dimorphism and pondered their existence, …

Analysis Of Alternative Oxidase In Non-Angiosperm Plants, Anissa M. Francis

Theses and Dissertations (Comprehensive)

Alternative oxidase (AOX) is a mitochondrial terminal oxidase that provides an alternative pathway for electron transport, allowing plants to maintain respiratory flexibility under environmental stress conditions. While AOX has been extensively studied in angiosperms (flowering plants), little is known about its distribution and conservation in non-angiosperms. Based on gaps identified in the literature, this thesis investigated the distribution of AOX across non-angiosperm plant lineages. Although AOX is present in many green algae and is therefore considered to be an ancient protein that originated before the existence of non-angiosperm plants, it remains unclear whether the protein is uniformly distributed across these …

Anoxia And Re-Oxygenation At Colder Temperatures In Goldfish (Carassius Auratus): Effects On Oxidative Stress And Metabolites, Matthew E. Trzcinski

Theses and Dissertations (Comprehensive)

Under the ice of ponds and lakes, goldfish (Carassius auratus) can survive weeks of anoxia at low temperatures by conserving ATP and by reducing their metabolic rate and relying on liver glycogen stores to meet their ATP demands using glycolysis. The following period of re-oxygenation is also known to be damaging in most vertebrates because it can lead to the generation of reactive oxygen species (ROS) that can cause oxidative damage to lipids, proteins and nucleic acids. Anoxia tolerant vertebrates such as the goldfish and crucian carp (Carassius carassius) accumulate reduced molecules with anoxia, overwhelming the …

Npr1 As A Temperature-Sensitive Regulator Of Pipecolic Acid-Mediated Plant Systemic Immunity, Spencer Tout

Theses and Dissertations (Comprehensive)

Healthy plant development requires balancing both abiotic (e.g. climate) and biotic (e.g. pathogen) challenges, which intercept important signaling pathways in plants. For example, climate change-associated elevated temperature can negatively modulate various aspects of plant immunity, including the production of central immune signals salicylic acid (SA) and N-hydroxypipecolic acid (NHP). Since SA and NHP signaling both require the master immune co-activator protein NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), it is important to investigate NPR1 as a potentially temperature-regulated molecular hub. Although the NPR1 gene is not transcriptionally downregulated at elevated temperatures (28° C vs. 23° C), little is known about …

Timing Of Migration And Seasonal Movements Of Arctic Grayling (Thymallus Arcticus) In Relation To Water Temperature In The Kakisa River And Upper Mackenzie River, Nwt: Results From An Acoustic Telemetry Study., Levi Snook

Theses and Dissertations (Comprehensive)

Arctic grayling (Thymallus arcticus) are a cold-water salmonid that inhabit waterbodies throughout the circumpolar regions of the northern hemisphere. In the last decade, Ka'a'gee Tu First Nation members as well as local sport fishers, have observed lower catches of Arctic grayling during their annual spawning run in the Kakisa River, NWT. Many potential causes of this decline have been hypothesized including climate change and over harvesting. Outside of the general annual spawning activity in the headwaters of the Kakisa River, the ecology of the population, including post-spawn habitat use and migratory patterns, remained understudied. To address these knowledge gaps, acoustic …

Exploring The Salinity Tolerance Of Zooplankton Communities On The Great Plains, Abbeneet Binning Bath, Derek Gray

Theses and Dissertations (Comprehensive)

Palaeoecological data shows fluctuating salinity levels in lakes across the Great Plains due to alternating wet and dry periods over the last two millennia. Droughts caused by this natural variation may be exacerbated by anthropogenic climate change, as the Great Plains are expected to become drier over the coming decades. As conditions become drier, the evaporation of water will increase the salinity of lakes across the region. Increases in salinity may significantly impact biodiversity, including important members of lake food webs such as zooplankton. Due to the region's history of alternating wet and dry periods, zooplankton may have adapted to …

Macroinvertebrate Communities And Food Web Structure In Tundra Streams Are Shaped By Substrate Size And Beaver Impoundments, Mathew K. Mervyn

Theses and Dissertations (Comprehensive)

North American beavers (Castor Canadensis) are expanding their range into the Arctic tundra as climate change drives earlier ice and snowmelt, and increased shrub cover. As ecosystem engineers, beavers build dams that alter water chemistry by creating impoundments within streams, trapping sediment and organic matter, and modifying nutrient cycling. This thesis evaluates how beaver impoundments interact with natural geomorphic variation in tundra streams and how impoundments affect tundra freshwater ecosystems in the western Canadian Arctic.

In Chapter 2, I compared water chemistry and benthic macroinvertebrate (BMI) community composition across 16 stream reaches, including those with and without beaver dams, with …

Feeling Blue: The Effects Of Blue Light Exposure On Reproduction And Physiology In Drosophila Melanogaster, Laura Hampel

Theses and Dissertations (Comprehensive)

Blue light, the wavelengths ranging from ~400-500 nm, is emitted from the sun and more recently, by artificial lights including those in technology. In humans, prolonged exposure to blue light has been consistently linked to circadian rhythm disruption and retinal damage, and has also been associated with changes in neurodegeneration, aging, mortality, and oxidative stress in model organisms. This thesis explores the multifaceted effects of blue light exposure through two independent but complementary approaches. An initial rapid review of the current state of knowledge on blue light induced oxidative stress in humans was conducted. This revealed that the most studied …

The Impacts Of Permafrost Thaw Slumps On Arctic Stream Ecology, Maria Dolan

Theses and Dissertations (Comprehensive)

Climate change is intensifying permafrost thaw across terrain of the circumpolar Arctic. Increased temperatures and rainfall at northern latitudes have resulted in the expansion of thermokarst features such as retrogressive thaw slumps, which make previously frozen debris available for transport into nearby river systems. In the Peel Plateau, Northwest Territories, the mobilization of these materials exposes rivers to a large quantity of sediment and solutes that may act as a chronic, press disturbance, potentially altering stream food webs. Here, I examine if: 1) thaw slumps have driven changes to the physical and biological properties of slump impacted streams since an …

Reversible Degradation Of Peptidoglycan By Lytic Transglycosylases, Aaron Devereaux

Theses and Dissertations (Comprehensive)

Antimicrobial resistance continues to be a burden on the global healthcare system with an estimated cost of billions of dollars and millions of deaths each year. Recently, there has been little to no development on new antibiotics to treat bacterial infection, and any that are developed become resisted to within a few years. Both Gram-positive and Gram-negative bacteria contain a mesh-like layer called peptidoglycan (PG) that surrounds their cells providing strength, cell shape, and protection from their environments. This layer is a polymer of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) connected via a b-1,4-glycosidic bond, with each strand being cross-linked …

Quantifying Ecological Processes Predicting Barren-Ground Caribou (Ɂetthën; Rangifer Tarandus Groenlandicus) Occurrence Across A Heterogenous Northern Indigenous Protected And Conserved Area., Eric Jolin

Theses and Dissertations (Comprehensive)

Northern ecosystems are experiencing a period of rapid and unprecedented change, with implications for species distributions, mammal community dynamics, and habitat associations. Understanding the ecological processes that shape species distributions is crucial for developing effective conservation strategies that can adapt to such change. This study examines drivers of barren-ground caribou occurrence, a species of cultural and ecological significance, across Thaıdene Nëné Indigenous Protected Area, an ecologically intact landscape of high habitat heterogeneity straddling the treeline of the Northwest Territories. I use spatial and temporal variation in caribou detections generated by camera traps to test the relative importance of apparent competition, …

Influence Of Temperature On Tfm Tolerance In Lake Sturgeon, Emily Bouffard

Theses and Dissertations (Comprehensive)

The lampricide, 3-trifluoromethyl-4-nitrophenol (TFM), has been used to successfully control invasive sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes for over 50 years. TFM’s effectiveness is due to the relatively low capacity of sea lamprey to detoxify TFM. Water temperature has been shown to increase TFM tolerance in larval sea lamprey. However, the effects of temperature on TFM sensitivity in non-target species such as the endangered lake sturgeon (Acipenser fulvescens) are poorly understood, particularly during their early life stages. To determine how temperature affected TFM sensitivity, age 1-year-plus (1+) lake sturgeon acclimated to 8, 16, …

Lichen It: Optimizing Post-Fire Caribou Lichen Transplantation And Assessment, Elise Brown-Dussault

Theses and Dissertations (Comprehensive)

Caribou lichen species are common in mid- to late-seral boreal forests, serving as an important winter diet staple for boreal woodland caribou. However, as climate change causes boreal wildfires to increase in size, severity, and frequency, available tracts of mature forest are decreasing, diminishing the extent of mature caribou lichen stands. Caribou lichens reproduce vegetatively, so bigger and more severe fires could exacerbate their dispersal limitations, potentially extending the timeline for caribou lichen stand recovery beyond 80 years. Trials have shown that “transplanting” caribou lichen fragments into disturbed areas can lead to the establishment of caribou lichen mats; as such, …

Characterizing The Targeting Of Toc159 Receptors To The Chloroplast Outer Envelope Membrane And Their Role In The Assembly Of Distinct Toc Complexes, Michael Fish

Theses and Dissertations (Comprehensive)

Global agriculture and food security face challenges from climate change, population growth, and other human-driven pressures. Enhancing our understanding of plant biology, particularly chloroplast function, is critical for improving crop yield and stress resilience. As the sites of photosynthesis and key regulators of plant responses to environmental cues, chloroplasts depend on the precise import of thousands of nuclear-encoded proteins to maintain their biogenesis and function. While much is known about the core translocon components in the chloroplast outer envelope membrane that form the TOC complex, the mechanisms underlying their targeting, assembly, and regulation remain incompletely understood.

Plastids, including chloroplasts, evolved …

Effect Of Rare Earth Element Mixtures On Daphnia Magna, Celine Do

Theses and Dissertations (Comprehensive)

Rare earth elements (REEs) are increasingly being used in modern technologies and as such, there is an increasing concern for the potential environmental risk associated with anthropogenic contamination. In addition to there being very little data available for individual REEs, there is also a lack of knowledge concerning mixtures. The objective of my study was to investigate the chronic effects of lanthanum (La) and yttrium (Y) as well as the acute effects of neodymium (Nd), praseodymium (Pr) and Y as a single metal and as a mixture to Daphnia magna. Standard 21-d chronic tests and 48-h single metal acute …

Comparing Ionoregulation And Modes Of Nitrogen Excretion Across The Life Cycle Of Parasitic And Non-Parasitic Lamprey Species, Shannon Davidson

Theses and Dissertations (Comprehensive)

Abstract

Ionoregulation and nitrogenous waste (N-waste) metabolism in fishes has been extensively documented in teleosts and elasmobranchs, but less so in lampreys (Petromizontiformes). All lamprey species undergo metamorphosis which drastically changes their physiology and modes of feeding. However, differences in ionoregulatory mechanisms due to anadromous versus non anadromous life history strategies emerge following metamorphosis in different lamprey species. Furthermore, some species, such as anadromous juvenile sea lamprey (Petromyzon marinus), are parasitic and migrate to seawater (SW) to ingest blood protein from host fishes, while juveniles of freshwater (FW), non-parasitic species, such as the American brook lamprey …

Investigating The Role Of The Mammalian Dsrnai Pathway In Preventing Infection By Respiratory Syncytial Virus And Human Coronavirus, Iliana Portelli

Theses and Dissertations (Comprehensive)

dsRNA interference (dsRNAi) is an antiviral innate immune response that uses long dsRNA (>40bp) to inhibit gene expression through the RNA interference (RNAi) pathway. dsRNAi is an important antiviral defense mechanism in plants, invertebrates, and fungi. However, its use as an antiviral mechanism in vertebrates is not well understood. Evidence proving the significance of dsRNAi in vertebrate cells does exist, but there is still a lack of research in this area, particularly with the use of long dsRNA. Respiratory Syncytial Virus (RSV) and human coronaviruses (HCoVs) are two single stranded RNA (ssRNA) viruses that infect airway cells. This study …

Elucidating Mechanisms Of Enhanced Dsrna-Nanophytoglycogen Innate Immune Responses In Healthy Human Cells, Nicholas Jadaa

Theses and Dissertations (Comprehensive)

Immunostimulatory nucleic acids, such as long double-stranded RNA (ds)RNA, can stimulate innate immune responses in a non-sequence specific manner. These molecules are recognized by pattern-recognition receptors in the cytoplasm, endosome, and on the cell surface. Activation leads to the production of mediators of innate immune pathways, including type I interferon and proinflammatory cytokines. Although these receptors are present in all cells, their role in non-immune cells is often overlooked due to their lower level of responsiveness. Nanocarriers can enhance these nucleic acid-mediated responses, allowing for exploration of innate immune pathways in non-immune cells. Nanoparticles as carriers of nucleic acids can …

The Effects Of Warmer Temperatures On The Physiology Of Invasive Sea Lamprey And Imperiled Populations Of Lake Sturgeon In The Laurentian Great Lakes, Milica Koledin

Theses and Dissertations (Comprehensive)

Invasive sea lamprey (Petromyzon marinus) contributed to massive declines in fisheries in the Laurentian Great Lakes due to their parasitism of large-bodied salmonid fishes in the 20^th century. Chemical control measures, which involve the application of 3-trifluoromethyl-4-nitrophenol (TFM) into rivers containing larval sea lamprey, were successfully implemented approximately 60 years ago to control populations. Recently, however, it was discovered that TFM tolerance increases in sea lamprey with a rise in temperature for reasons which are incompletely understood. Nor is it understood how sea lamprey will respond to warmer temperatures due to climate change, which could affect their …

Impacts Of Environmental Stressors On Mummichog (Fundulus Heteroclitus) Growth And The Gh-Igf1 Pathway Using A Laboratory Bioassay, Olena Kuntyj

Theses and Dissertations (Comprehensive)

Using a flow-through laboratory bioassay, experiments investigated the effects of limited feeding, increased temperature, ammonium chloride (NH₄Cl), and 17α-ethinylestradiol (EE₂) on juvenile mummichog (Fundulus heteroclitus) growth. Weight measurements were taken every three days as the apical growth endpoint. Gene expression was examined by qPCR for genes in the GH (growth hormone)-IGF1 (insulin-like growth factor 1) pathway, including gh, igf1, and their receptors (ghra, ghrb, igf1ra, igf1rb). In Experiment 1, juvenile mummichog were exposed to excess or limited feed for 21 days. The limited-fed mummichog weighed less, were …

Evaluating The Risk Posed By Gadolinium In The Grand River Watershed, Johann Memmel

Theses and Dissertations (Comprehensive)

Gadolinium (Gd) is a rare earth element (REE), primarily used in contrast agents for magnetic resonance imaging (MRI), with additional applications in metallurgy, phosphors, neutron shielding, and other niche applications. Both Gd and Gd-based contrast agents (GBCAs, the form used for MRIs) have been detected downstream of wastewater effluent discharges and there is currently little research into the risk this poses to aquatic ecosystems. This study investigated the potential environmental risks of Gd and GBCAs using the Grand River watershed (GRW) in southwestern Ontario as a model ecosystem due to it containing a variety of land uses (urban, industrial, agricultural) …

Fishes In Murky Waters: Effects Of Total Suspended Solids On Fish Gills And Performance, Xena Montoya

Theses and Dissertations (Comprehensive)

Total suspended solids (TSS) naturally occur in aquatic habitats, but climate change and other anthropogenic disturbances can lead to increased levels. Exposure to high levels of TSS has the potential to damage fish gills through abrasion, leading to impairment of gill function and fish physiology. However, little work has been done exploring the linkages between TSS-induced gill damage and animal performance. Therefore, we tested the hypothesis that TSS damages gill structure, causing gill dysfunction and reducing swimming performance. We exposed salmonids (rainbow trout, brook trout and cutthroat trout) and non-salmonids (fathead minnow and longnose dace) to different TSS concentrations (0-1000 …

Assessing Stormwater Management Pond Water Quality, Function, And The Potential Biotic Effects To Receiving Waters, Mitchell Elstone

Theses and Dissertations (Comprehensive)

The use of stormwater management ponds (SWMPs) has been increasing over the past five decades. However, an in-depth understanding of the daily performance of SWMPs and functionality during cold periods is limited. This is in part because mandated monitoring is relatively infrequent, and the assumption that SWMPs are inactive between storm events and during the winter. The goals of this research were to better understand daily stormwater (SW) characteristics, the performance of SWMPs based on current forms of evaluation and assess the potential for SWMP effluent to impact downstream biota. Influent and effluent samples from two SWMPs were collected daily …

A Comparative In Vitro Investigation Of Rainbow Trout Vig-3 And Human Isg15, Kristof Jenik, Sarah J. Poynter, Shanee Herrington-Krause, Kayla Samms, Nichole Sanchez Diaz, Stephanie J. Dewitte-Orr, Tania Rodriguez-Ramos, Brian Dixon, Adebisi Sanyaolu, Tamiru Alkie, Bryce M. Warner, Nikesh Tailor, Shawna Semple

Theses and Dissertations (Comprehensive)

The aquaculture industry is a big part of the global economy, supplying food and supporting many livelihoods, yet it faces formidable challenges from diverse aquatic pathogens, especially viruses. Effective antiviral treatments are lacking for both humans and economically significant farmed fish like rainbow trout (Oncorhynchus mykiss). When viruses invade host cells, pattern recognition receptors detect viral components, initiating intracellular signaling and type I interferon (IFN-I) production. IFN-I triggers interferon-stimulated genes (ISGs) that establish an antiviral state in infected and nearby cells, curbing viral spread. In rainbow trout, a particularly understudied ISG is viral hemorrhagic septicemia virus (VHSV)-induced gene 3 (vig-3), …

Laurier Biology Departmental Seminars Poster Colouring Book (Vol 2), Tristan A.F. Long

Biology Faculty Publications

Welcome to Volume 2 of the Wilfrid Laurier University Department of Biology seminar series poster collection! When I was compiling a colouring book based on academic seminar posters last year, I had no idea how well it would be received. As of this writing, Volume 1 has been downloaded almost 1000 times (!): https://scholars.wlu.ca/biol_faculty/94/, and was featured in a great article by Cheyenne Bholla: https://www.therecord.com/news/waterloo-region/2022/04/27/laurier-biology-profs-science-posters-have-been-turned-into-a-downloadable-colouring-book.html.

So, I guess it’s time for a sequel, featuring some more of my favourite designs! This time round I’ve included several sets of posters – often drawn years apart – that are thematically …

Temperature Regulation Of Plant- Rhizobacteria Interactions Within The Soil-Rhizosphere- Rhizoplane Interface, Eric J. R. Marchetta

Theses and Dissertations (Comprehensive)

An optimal microbiome is important for plant health and can prime subsequent plant immune responses to enhance stress resilience. However, the molecular mechanisms that dynamically drive host-microbiome interactions and subsequent induced systemic resistance (ISR) responses in plants under elevated environmental temperatures remain underexplored. To address this major knowledge gap, this thesis further investigated Canadian soil-inhabiting rhizobacteria that had been previously shown to activate ISR in tomato (Solanum lycopersicum) plants. Specifically, this study characterized the in vitro physiology of these rhizobacterial strains under different temperatures, including growth, phosphate solubilization abilities and direct anti- pathogenic capabilities. Temperature-sensitivity of these parameters …

Differences In Drifting Invertebrate Communities Across Arctic Ecozones And The Influence On Potential Growth Of Grayling (Thymallus Arcticus), Charles Chanyi

Theses and Dissertations (Comprehensive)

Invertebrate drift is a key process that potentially affects multiple levels of food web organization within stream environments. However, our understanding of the mechanistic drivers of drift in high latitude streams and subsequent bottom-up control that drift may have on fish predators in these environments remains understudied. This project aimed to gain the baseline knowledge of how drift functions across two major high latitude ecozones, the boreal forest and tundra, and how those possible differences in drifting community characteristics may impact drift-feeding Arctic grayling (Thymallus arcticus). These objectives were accomplished by characterizing stream environments across both ecozones, sampling …

Temperature Regulation Of Pipecolic Acid-Mediated Plant Systemic Immunity In Arabidopsis Thaliana, Alyssa Shields

Theses and Dissertations (Comprehensive)

Significant crop losses are caused by pathogenic infections annually, which are exacerbated by increasing global temperatures due to climate change. One way by which plants respond to pathogenic attacks is through the activation of pattern-triggered immunity (PTI), effector-triggered immunity (ETI), and systemic acquired resistance (SAR), which lead to production of the central defence phytohormone salicylic acid (SA). Accompanying SA release is the putative mobilization of pipecolic acid (Pip), which acts as an immune regulatory plant metabolite that works with and independently from SA. As demonstrated in the model plant Arabidopsis thaliana following infection with the model bacterial pathogen Pseudomonas syringae …

The Effect Of Alkalinity On Lampricide Effectiveness And Gill Physiology In Invasive Sea Lamprey (Petromyzon Marinus), Alexandre J. Walsh

Theses and Dissertations (Comprehensive)

The pesticides, 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide are used to control populations of invasive sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes of North America. Added to streams infested with larval sea lamprey, the effectiveness of these pesticides, commonly called lampricides, are strongly influenced by water pH, with greater toxicity for both TFM and niclosamide in lower pH than higher pH water. However, the TFM and niclosamide sensitivity of sea lamprey are also greater in poorly buffered, low alkalinity water than in high alkalinity water but it is unclear why. One goal of my thesis was to propose …

Characterization Of The Clostridioides Difficile Glycosyl Hydrolase Ccsz, Brian Lowrance

Theses and Dissertations (Comprehensive)

Bacteria inhabit many of the harshest environments on Earth; persisting and thriving in conditions thought to be unsuitable for life. One common strategy to withstand these environments is the formation of a biofilm. Biofilm composition varies greatly, depending on the underlying community that produces it. Cellulose, a polymer consistently prevalent in biofilms, has been identified as a virulence factor in many pathogens and is suspected to be involved in pathogenesis by Clostridioides difficile. C. difficile is the #1 cause of hospital acquired diarrhea, which can range from mild to life-threatening infections. Biofilm formation is hypothesized to be involved in …