Digital Commons Network^™

Cold Hardiness And Deacclimation Of Overwintering Papilio Zelicaon Pupae, Caroline M. Williams, Nicolai Annegret, Brent J. Sinclair, Laura V. Ferguson, Mark A. Bernards, Jessica J. Hellmann

Biology Publications

Seasonally-acquired cold tolerance can be reversed at warm temperatures, leaving temperate ectotherms vulnerable to cold snaps. However, deacclimation, and its underlying mechanisms, has not been well-explored in insects. Swallowtail butterflies are widely distributed but in some cases their range is limited by low temperature and their cold tolerance is seasonally acquired, implying that they experience mortality resulting from deacclimation. We investigated cold tolerance and hemolymph composition of Anise swallowtail (Papilio zelicaon) pupae during overwintering in the laboratory, and after four days exposure to warm temperatures in spring. Overwintering pupae had supercooling points around − 20.5 °C and survived …

A Cross-Seasonal Perspective On Local Adaptation: Metabolic 1 Plasticity Mediates Responses To Winter In A Thermal-2 Generalist Moth, Brent J. Sinclair, Caroline M. Williams, Wesley D. Chick

Biology Publications

No abstract provided.

It Takes An Individual Plant To Raise A Community: Trflp Analysis Of The Rhizosphere Microbial Community Of Two Pairs Of High- And Low-Metal-Accumulating Plants, Melanie P. Columbus, Sheila Macfie

Biology Publications

We used terminal restriction fragment length polymorphism (TRFLP) analysis to look at the microbial community profiles of the rhizosphere surrounding two pairs of high- and low-metal (Cd)-accumulating plants (Brassica and Triticum). Unexpectedly, the microbial community did not vary with soil type, time, plant type, or metal-accumulating ability of the plant. Instead, when a plant's metal-accumulating ability was well matched to the level of metal contamination in the soil, the microbial populations in the rhizosphere were different than those of the seed endophytes and bulk soil. Unmatched plants had the same microbial community as bulk soil. The plant interaction …

Changing The Substrate Specificity Of Arogenate Dehydratases (Adts) From Arabidopsis Thaliana., Megan Es Smith-Uffen

Electronic Thesis and Dissertation Repository

Phenylalanine (Phe), an essential aromatic amino acid, serves as a precursor for protein synthesis and a variety of secondary metabolites in plants. Two pathways are known for Phe biosynthesis. In the first, prephenate dehydratases (PDTs) convert prephenate to phenylpyruvate, which is transaminated to Phe. In the second, prephenate is transaminated to arogenate, which is converted to Phe by arogenate dehydratases (ADTs). ADTs and PDTs are structurally very similar, as are their substrates. Six ADTs (ADT1-ADT6) have been identified in Arabidopsis thaliana. ADT1 and ADT2 can recognize both prephenate and arogenate as substrates whereas ADT3-ADT6 are solely arogenate-accepting. Twenty ADT domain-swapping …

The Relative Importance Of Number, Duration, And Intensity Of Cold Stress Events In Determining Survival And Energetics Of An Overwintering Insect, Katie E. Marshall, Brent J Sinclair

Biology Publications

1. The relationship between abiotic stress and fitness in an individual is usually described by the intensity and duration of stress. Yet in natural systems, variability in abiotic stress is common. Since individuals have physiological and fitness responses to single bouts of stress, frequency of stress may also determine the lifetime success of an organism. However, the majority of laboratory studies have focused only on the effects of single stress events.
2. We investigated the relative importance of stress parameters including duration, intensity and number of cold events on the short-term physiology and long-term fitness in the freeze-avoiding eastern spruce budworm Choristoneura …

Social Immunity And The Expression Of Immune-Related Genes In The Eastern Subterranean Termite, Qi Gao

Electronic Thesis and Dissertation Repository

Individuals living within social groups may benefit from the efficiencies of division of labour, but on the other hand render themselves vulnerable to socially transmitted disease. This cost to social living should promote cooperative barriers to disease transmission, especially in eusocial taxa where spatial and genetic proximity to nestmates are characteristically pronounced. Though studies of the immunity at multiple levels in social species are becoming more common, little is known about how their sociality is deployed to resist contagion. By exposing the Eastern subterranean termite Reticulitermes flavipes to entomopathogenic fungi, I studied their immune responses at multiple levels. At the …

Editorial Overview: Environmental Physiology: Insect Environmental Physiology, Brent J. Sinclair

Biology Publications

No abstract provided.

Olanzapine-Induced Methylation Alters Cadherin Gene Families And Associated Pathways Implicated In Psychosis, Melkaye G. Melka, Christina A Castellani, Nagalingam Rajakumar, Richard O'Reilly, Shiva M Singh

Biology Publications

BACKGROUND: The complex aetiology of most mental disorders involves gene-environment interactions that may operate using epigenetic mechanisms particularly DNA methylation. It may explain many of the features seen in mental disorders including transmission, expression and antipsychotic treatment responses. This report deals with the assessment of DNA methylation in response to an antipsychotic drug (olanzapine) on brain (cerebellum and hippocampus), and liver as a non-neural reference in a rat model. The study focuses on the Cadherin/protocadherins encoded by a multi-gene family that serve as adhesion molecules and are involved in cell-cell communication in the mammalian brain. A number of these molecules …

Two Spotted Spider Mite (Tetranychus Urticae) Selection To Arabidopsis Thaliana, Huzefa Ratlamwala

Electronic Thesis and Dissertation Repository

Spider mite feeding on A. thaliana induces the production of indole glucosinolates (IGs), plant secondary metabolites that negatively affect mite performance. In this study I conducted selection experiments on A. thaliana with varying levels of IGs, to determine if mites could adapt to IGs and other defense compounds. After 12 months, mites reared on host with IGs performed significantly better on A. thaliana than mites maintained on beans. However, an adaptation cost was detected between selected mite lines and their ancestral host. The qRT-PCR data on different mite lines revealed that the detoxification genes previously identified may only be involved …

Nitrogen Fixation By The Cyanobacterium Nostoc Punctiforme In Response To Variation In Nitrogen Availability, Temperature, And Atmospheric Co2 Concentrations, Danielle A. Griffith

Electronic Thesis and Dissertation Repository

The predominant input of available nitrogen (N) in boreal forest ecosystems originates from moss-associated cyanobacteria, which fix unavailable atmospheric N₂, contribute to the soil N pool, and thereby support forest productivity. Although increases in N availability, temperature, and atmospheric CO₂ concentrations are expected in Canada’s boreal region over the next century, little is known about the combined effects of these factors on N₂ fixation by axenic cyanobacteria or the associated mechanisms. I assessed changes in N₂ fixation by Nostoc punctiforme under different global environmental change scenarios and examined correlations between the response and changes in …

The Role Of Lactate Dehydrogenase B In Aerobic Glycolysis-Mediated Resistance To Ab Toxicity, Tyler Tam

Electronic Thesis and Dissertation Repository

Alzheimer’s disease is a progressive, neurodegenerative disorder characterized by the accumulation of amyloid β (Aβ) plaques in affected brain regions. Strong evidence indicates that Aβ exerts neurotoxic effects by promoting mitochondrial dysfunction and ROS production, leading to widespread oxidative damage and activation of pro-apoptotic mechanisms. Past investigations suggest that neuronal resistance to Aβ toxicity is partly mediated by a Warburg Effect-like metabolism, in which cells exhibit elevated glycolytic activity and lactate production, while limiting mitochondrial respiration. Elevated lactate dehydrogenase A (LDHA) activity, which catalyzes lactate production from pyruvate, has been demonstrated to counter Aβ-induced oxidative stress and neurotoxicity, however the …

Exploring The Complexity Of Intellectual Disability In Fetal Alcohol Spectrum Disorders, Aniruddho Chokroborty-Hoque, Bonnie Alberry, Shiva M. Singh

Biology Publications

Brain development in mammals is long lasting. It begins early during embryonic growth and is finalized in early adulthood. This progression represents a delicate choreography of molecular, cellular, and physiological processes initiated and directed by the fetal genotype in close interaction with environment. Not surprisingly, most aberrations in brain functioning including intellectual disability (ID) are attributed to either gene(s), or environment or the interaction of the two. The ensuing complexity has made the assessment of this choreography, ever challenging. A model to assess this complexity has used a mouse model (C57BL/6J or B6) that is subjected to prenatal alcohol exposure. …

The Overwintering Biology Of The Acorn Weevil, Curculio Glandium In Southwestern Ontario., Hiroko Udaka, Brent J Sinclair

Biology Publications

The acorn weevil, Curculio glandium, is a widespread predator of acorns in eastern North America that overwinters in the soil as a larva. It is possible that low temperatures limit its northern geographic range, so we determined the cold tolerance strategy, seasonal variation in cold tolerance, and explored the physiological plasticity of overwintering larvae. Weevil larvae were collected from acorns of red and bur oak from Pelee Island, southwestern Ontario in fall 2010 and 2011. C. glandium larvae are freeze avoidant and larvae collected from bur oak acorns had lower supercooling points (SCPs: -7.6±0.36°C, LT50: -7.2°C) than those collected from …

Immune Function And Infection Status Is Related To Migration Distance And Phases Of The Annual Cycle In Song Sparrows (Melospiza Melodia), Tosha R. Kelly

Electronic Thesis and Dissertation Repository

Life history theory predicts animals adjust immune investment based on their risk of encountering familiar and unfamiliar parasites. Although long-distance migrants may encounter a greater diversity of parasites than short-distance migrants, the energetic costs of migration may constrain immune investment. However, few studies have investigated the relationship between migration distance and immunity. I used stable isotope analysis to estimate the wintering latitude, and thus migration distance, of song sparrows (Melospiza melodia). I assessed whether migration distance was related to the incidence of infection with a blood-borne parasite, parasite load, and immune function. The incidence of infection increased with …

Early Mechanisms Of Retinal Degeneration In The Harlequin Mouse, Eric Dolinar

Electronic Thesis and Dissertation Repository

Retinal diseases are personally debilitating and expensive, yet many early disease mechanisms leading to their onset and progression remain poorly understood. The harlequin mouse is a model of human mitochondrial dysfunction and parainflammation leading to subsequent cerebellar and retinal degeneration. Diagnosis of retinal degeneration can be tracked in vivo and is associated with AIF dysfunction. Here, retinal dysfunction in the harlequin mouse was first quantified using electroretinography followed by assay of blood-retinal-barrier integrity and transcriptome alterations in young adulthood. Nonmetric multidimensional scaling of oscillatory potentials provided a novel, comprehensive assessment of inner-retinal health and can detect shifts in OP parameters. …

Seed Tuber Treatments With Pseudomonas Spp. To Reduce Potato Common Scab Incidence And Severity, Muna Basahi

Electronic Thesis and Dissertation Repository

Potato common scab is a tuber- or soil-borne disease caused by several species in the genus Streptomyces. The objective of this study was to study the treatment of seed tubers with Pseudomonas spp. as a means to reduce common scab incidence and severity, and improve seed tuber quality and marketability. All four Pseudomonas spp. tested inhibited Streptomyces SS-1; PEI-1 and AL-1 in vitro.

In laboratory trials, treatments of seed tubers with Pseudomonas strains A25, A145, and A153, significantly reduced in the number of pathogenic Streptomyces in comparison to untreated tubers within five weeks (P<0.05). Seed tuber treatments with A25 and A153 significantly reduced scab incidence and severity in Russets Burbank and Prospect, respectively. This study also demonstrated the use of TaqMan qPCR detecting the txtAB gene analysis as …

Islet Regenerative Properties Of Ex Vivo Expanded Hematopoietic Progenitor Cells, Ayesh K. Seneviratne

Electronic Thesis and Dissertation Repository

Human umbilical cord blood (UCB) progenitor cells with high aldehyde dehydrogenase activity (ALDH^hi), can stimulate endogenous islet regeneration after transplantation into mice with steptozotocin (STZ)-induced diabetes. However, UCB ALDH^hi cell are extremely rare, and expansion will be required to develop cell-mediated strategies to treat patients with diabetes. To increase the number of progenitor cells available for clinical application, we expanded ALDH^hi UCB cells under clinically applicable, serum-free hematopoietic-restricted conditions. 6 day expansion resulted in a 15-fold increase in total cell number, and a 3-fold increase in the number of HPC retaining high ALDH (ALDH^hi HPC) …

Metabolic Suppression In Mammalian Hibernation: The Role Of Mitochondria., James F Staples

Biology Publications

Hibernation evolved in some small mammals that live in cold environments, presumably to conserve energy when food supplies are low. Throughout the winter, hibernators cycle spontaneously between torpor, with low metabolism and near-freezing body temperatures, and euthermia, with high metabolism and body temperatures near 37°C. Understanding the mechanisms underlying this natural model of extreme metabolic plasticity is important for fundamental and applied science. During entrance into torpor, reductions in metabolic rate begin before body temperatures fall, even when thermogenesis is not active, suggesting active mechanisms of metabolic suppression, rather than passive thermal effects. Mitochondrial respiration is suppressed during torpor, especially …

Identifying The Role Of Non-Native Species In The Enhanced Trophic Transfer Of Mercury In The Food Web Of Lake Erie, A North American Great Lake, Kaylin M.S. Liznick

Electronic Thesis and Dissertation Repository

Increasing mercury (Hg) concentrations in top predatory fish is concerning for human and wildlife health. This study examined the amount of Hg available to the food web of Lake Erie, and explored the role that two recently established non-native species, dreissenid mussels and round goby, have played in the trophic transfer of Hg to sport fish. A comprehensive sampling of total Hg (THg) and methylmercury (MeHg) within Lake Erie water, sediment and seston with high temporal and spatial resolution describes environmental concentrations. In addition, biotic THg and MeHg are quantified in benthic invertebrates and three fish species. A steep spatial …

Associations Between Hypothalamic-Pituitary-Adrenal Axis System Gene Variants And Cortisol Reactivity In Preschoolers: Main Effects And Gene-Environment Interactions, Haroon I. Sheikh

Electronic Thesis and Dissertation Repository

Exposure to stressful events during early development has consistently been shown to produce long lasting effects on the hypothalamic-pituitary-adrenal (HPA) axis, which may increase vulnerability to mood and anxiety disorders. Recently reported genetic association studies indicate that these disorders may be influenced, in part, by gene-environment interactions (GxE) involving polymorphisms within the corticotrophin-releasing hormone and monoaminergic system genes. However, little is known about how genetic variants and life stress work to shape children’s neuroendocrine reactivity and emerging symptoms. Therefore, the aim of this thesis is to examine main effects of candidate genes and GxE on the neuroendocrine stress response and …

Long-Term Genomic And Epigenomic Dysregulation As A Consequence Of Prenatal Alcohol Exposure: A Model For Fetal Alcohol Spectrum Disorders, Morgan L Kleiber, Eric J Diehl, Benjamin I Laufer, Katarzyna Mantha, Aniruddho Chokroborty-Hoque, Bonnie Alberry, Shiva M Singh

Biology Publications

There is abundant evidence that prenatal alcohol exposure leads to a range of behavioral and cognitive impairments, categorized under the term fetal alcohol spectrum disorders (FASDs). These disorders are pervasive in Western cultures and represent the most common preventable source of neurodevelopmental disabilities. The genetic and epigenetic etiology of these phenotypes, including those factors that may maintain these phenotypes throughout the lifetime of an affected individual, has become a recent topic of investigation. This review integrates recent data that has progressed our understanding FASD as a continuum of molecular events, beginning with cellular stress response and ending with a long-term …

Divergent Transcriptional Responses To Low Temperature Among Populations Of Alpine And Lowland Species Of New Zealand Stick Insects (Micrarchus)., Luke T Dunning, Alice B Dennis, Brent J Sinclair, Richard D Newcomb, Thomas R Buckley

Biology Publications

In widespread and genetically structured populations, temperature variation may lead to among-population differentiation of thermal biology. The New Zealand stick insect genus Micrarchus contains four species that inhabit different thermal environments, two of which are geographically widespread. RNA-Seq and quantitative PCR were used to investigate the transcriptional responses to cold shock among lowland and alpine species to identify cold-responsive transcripts that differ between the species and to determine whether there is intraspecific geographical variation in gene expression. We also used mitochondrial DNA, nuclear 28S ribosomal DNA and transcriptome-wide SNPs to determine phylogeographic structure and the potential for differences in genetic …

The Apl5 Subunit Of The Ap3 Adaptor Protein Complex Is Required For Cytokinesis Checkpoint Function In Schizosaccharomyces Pombe, Joy Wang

Electronic Thesis and Dissertation Repository

This study investigates the role of Apl5p in the complex regulatory network of Schizosaccharomyces pombe, which ensures the faithful and reliable completion of cytokinesis. This network, referred to as the cytokinesis checkpoint, ensures successful cell division upon perturbances to the cytokinetic machinery (e.g. disruption of the actin cytoskeleton). Apl5p has been identified as a putative regulator of the cytokinesis checkpoint based on the hyper-sensitivity of apl5D mutants to the actin depolymerizing drug, Latrunculin A. Apl5p is an essential subunit of the conserved AP3 adaptor complex, which is suspected to be involved in vesicular trafficking. Thus, I hypothesized that Apl5p …

Testing For Positive Edge Responses In A Fragmented Landscape In The Eastern Tiger (Papilio Glaucus) And The Spicebush (P. Troilus) Swallowtail Butterflies, Jenna C. Siu

Electronic Thesis and Dissertation Repository

Landscape changes such as habitat fragmentation and habitat loss are contributing to a global decline in biodiversity. While habitat fragmentation research has mainly focused on species that avoid edges, or the boundaries between different landcover types (negative edge response), a hypothesized resource distribution model predicts that species that require complementary resources in different landcovers will be most abundant at edges (positive edge response). Adults of Eastern Tiger (Papilio glaucus) and Spicebush (P. troilus) swallowtail butterflies require forests for oviposition sites and meadows for nectar resources. I examined the relative abundance and flight orientation of both species …

Ubiquitin-Mediated Degradation Via Ups And Lysosome, Qizhi Sun

Electronic Thesis and Dissertation Repository

Ubiquitination plays a fundamental role in determining protein fate. Once ubiquitinated, the cargo is directed to the proteasome for partial or complete degradation or lysosome for complete degradation. Failing to eliminate these cargos results in the accumulation of toxic proteins that contribute to neurodegenerative and immunological diseases, cancer and other human maladies. Thus, identifying proteins subject to ubiquitin-mediated degradation and characterizing the mechanisms governing these processes underscores their importance to human health. The calcium/calmodulin-dependent serine protein kinase (CASK) is one such protein that is required for brain development. However, mutations that cause CASK to accumulate are correlated to X-linked mental …

Population Genetic Structure In The Pitcher Plant Flesh Fly Fletcherimyia Fletcheri, John R. O'Leary

Electronic Thesis and Dissertation Repository

The study of population genetic structure in the pitcher plant flesh fly, Fletcherimyia fletcheri, is an important step in bettering our understanding of dispersal abilities, gene flow, and behavior in the species. In this paper, an extended sampling of populations across Algonquin Provincial Park was performed to elucidate an effective scale of genetic differentiation in F. fletcheri. Genetic differentiation between sites was compared to interceding landscape composition, and digital dispersal models were developed, testing the hypothesis that F. fletcheri uses aquatic tributaries for dispersal between peatlands. Data were collected on 613 specimens from 15 populations, and population differentiation …

Biological Relevance Of Cnv Calling Methods Using Familial Relatedness Including Monozygotic Twins, Christina A. Castellani, Shiva M. Singh, Elizabeth O. Locke

Biology Publications

Studies involving the analysis of structural variation including Copy Number Variation (CNV) have recently exploded in the literature. Furthermore, CNVs have been associated with a number of complex diseases and neurodevelopmental disorders. Common methods for CNV detection use SNP, CNV, or CGH arrays, where the signal intensities of consecutive probes are used to define the number of copies associated with a given genomic region. These practices pose a number of challenges that interfere with the ability of available methods to accurately call CNVs. It has, therefore, become necessary to develop experimental protocols to test the reliability of CNV calling methods …

Transgenic Plants As Novel Bioreactors To Produce Human Protein, Nadiyah Alqazlan

Electronic Thesis and Dissertation Repository

Plants have emerged in the past decade as a suitable alternative to the current production systems for recombinant pharmaceutical proteins. This project aims to develop plants as a green bioreactor for large-scale and cost-effective production of human therapeutic proteins. Several binary plant expression vectors were designed and constructed to express a human protein. The constructed plant expression vectors were transferred to Agrobacterium prior to plant transformation. By using Agrobacterium-mediated plant transformation, both transient expression in N. benthamiana plants and stable expression of the human protein in Nicotiana tabacum cv.81V9 were achieved. Immunoassays such as Western blot and ELISA (the enzyme-linked …

Signaling Events During Extraembryonic Endoderm Differentiation, Jason Taek Ki Hwang

Electronic Thesis and Dissertation Repository

Mouse F9 cells differentiate into primitive endoderm (PrE) when treated with retinoic acid (RA) and into parietal endoderm (PE) following subsequent treatment with dibutyryl cAMP. Wnt6 is up-regulated in PrE cell, and although it is sufficient to induce differentiation by signaling through the canonical WNT/β-catenin pathway, the mechanism by which the Wnt6 gene is regulated is not known. In addition to WNT signaling, PrE differentiation is accompanied by an increase in reactive oxygen species (ROS). ROS have been implicated in regulating the canonical WNT/β-catenin signaling pathway through Nucleoredoxin (NRX), but whether they are sufficient to induce extraembryonic endoderm in vitro …

Sirna Targeting Of Thymidylate Synthase, Thymidine Kinase 1 And Thymidine Kinase 2 As An Anticancer Therapy: A Combinatorial Rnai Approach, Christine Di Cresce

Electronic Thesis and Dissertation Repository

Thymidylate synthase (TS) is the only de novo source of thymidylate (dTMP) for DNA synthesis and repair. Drugs targeting TS protein are a mainstay in cancer treatment but off-target effects and toxicity limit their use. Cytosolic thymidine kinase (TK1) and mitochondrial thymidine kinase (TK2) contribute to an alternative dTMP-producing pathway, by salvaging thymidine from the tumour milieu, and may modulate resistance to TS-targeting drugs. We have previously shown that TS antisense molecules (oligodeoxynucleotides, ODNs, and small interfering siRNA, siRNA) sensitize tumour cells, both in vitro and in vivo, to TS targeting drugs. As both TS and TKs contribute to cellular …