Life Sciences Commons^™

Investigating Mycelial-Crop Residue Mat Application To Reduce Early-Colonizing Weeds In Row-Crop Agriculture, Donald T. Watson

Electronic Thesis and Dissertation Repository

Herbicide use within conventional agriculture has contributed to greatly increased crop yields since its widespread adoption, but environmental concerns regarding overuse and reliance on selective herbicides continue to mount. Using five fungal species and two crop residues in a factorial design, I created a novel slurry to control weeds through inhibition by the mycelial mat formed after application to soil. I monitored weed stem counts and the strength of the mycelial mat under the treatments. Additionally, as a proxy for crop yield, I measured the wet and dry mass of crop plant grown under application treatments. Weed prevalence was significantly …

Hibernation Is Super Complex: Dynamics Of Electron Transport System Supercomplexes, Amalie J. Hutchinson

Electronic Thesis and Dissertation Repository

The electron transport system complexes form supercomplexes (SCs) within mitochondrial membranes, perhaps increasing respiratory capacity or reducing reactive oxygen species production. My project aimed to determine the abundance, composition, and stability of SCs in a hibernator. Hibernators have dynamic metabolisms that change greatly during the winter. I isolated mitochondria from rats and thirteen-lined ground squirrels (TLGS) in different hibernation states and measured mitochondrial respiration. I extracted mitochondrial proteins using two detergents of different strengths, and quantified SC abundance using 2-dimensional gel electrophoresis and immunoblotting. Rats had fewer SCs than TLGS. SCs are dynamic in hibernation and the complex III composition …

Fear Of Large Carnivores Is Tied To Ungulate Habitat Use: Evidence From A Bifactorial Experiment, Haley K. Epperly, Michael Clinchy, Liana Y. Zanette, Robert A. Mcceery

Biology Publications

The fear large carnivores inspire in large ungulates has been argued to have cascading effects down food webs. However, a direct link between ungulate habitat use and their fear of large carnivores has not been experimentally tested. To fill this critical gap, we conducted a bi-factorial experiment in an African savanna. We removed shrub cover and broadcast large carnivore vocalizations (leopard, hyena, dog) or non-threatening control vocalizations in both experimentally cleared and shrubby control sites. We recorded the proactive (frequency of visitation) and reactive (fleeing or vigilance) responses of multiple prey (impala, warthog, nyala and bushbuck). Critically, we found a …

Direct Electrical Stimulation Of Prefrontal Cortex Modulates The Transient Heart Rate Response To Exercise In Conscious Humans, Bartek Kulas

Electronic Thesis and Dissertation Repository

Prefrontal cortical regions play an essential role in generating appropriate cardiovascular adjustments, particularly in cardio-vagally mediated heart rate (HR) responses to active tasks. Functional imaging studies provide correlational evidence that this region coordinates HR responses to exercise, however, direct experimental evidence of prefrontal cortical HR regulation in humans is not available. Seven persons with epilepsy implanted with intracranial electroencephalography (iEEG) completed 2-second isometric handgrip (IHG) contractions at no-stimulation (NO-STIM) or sham-stimulation (SHAM) conditions, and during direct electrical stimulation (STIM) of the orbitofrontal and medial prefrontal cortex. HR responses to IHG during NO-STIM and SHAM increased HR by Δ4.9±2.7 bpm, compared …

Metschnikowia Mitochondria, Dong Kyung Lee

Electronic Thesis and Dissertation Repository

Mitochondrial genomes are known for their diverse characteristics and are an attractive model to study genome evolution. Draft nuclear genomes of 71 Metschnikowia yeast strains are publicly available but their mitochondrial genome assemblies are incomplete, thereby making genome studies difficult. To remediate this shortcoming, complete mitochondrial genomes of 71 Metschnikowia strains were assembled from the draft nuclear genomes. Metschnikowia mitochondrial genomes exhibit an unprecedented amount of diversity, particularly with respect to the frequency and distribution of introns, which is often reflected upon overall genome size variations. Additionally, loss of synteny between strains of the same species further strengthens the notion …

Establishment Of A Pesticide Resistance Monitoring Tool For The Two-Spotted Spider Mite, Tetranychus Urticae, Hanna Varonina

Electronic Thesis and Dissertation Repository

Two-spotted spider mite (TSSM), or Tetranychus urticae (Koch), is a major agriculture pest known for its rapid development of resistance to pesticides. The analysis of spider mites’ pesticide resistance demonstrated that resistance patterns and frequencies vary between T. urticae strains collected from different geographic locations and host plants. This research aims at characterization of pesticide resistance patterns in mite populations present in greenhouses in the Southwestern Ontario by identifying genetic and metabolic markers of their pesticide resistance. The establishment of these markers lays the basis for development of a pesticide resistance diagnostic tool that will enable prediction of population resistance …

The Effects Of Silver Nanoparticles On Soybean (Glycine Max) Growth And Nodulation, Paul J. Boersma

Electronic Thesis and Dissertation Repository

Due to their antimicrobial properties, silver nanoparticles (AgNPs) have become more popular in consumer and industrial products, leading to increasing agricultural and environmental concentrations. Exposure to AgNPs could be detrimental to plants, microbes, and their symbiotic relationships. When subjected to 10 µg/mL AgNPs in a 96-well plate, growth of Bradyrhizobium japonicum USDA 110 was halted. In hydroponic culture with 2.5 µg/mL AgNPs, biomass of inoculated Glycine max (L.) Merr. was 50% of control. Axenic plants were unaffected by this dose, but growth was inhibited at higher doses, indicating that AgNPs inhibit both nodulation and growth. Nodules treated with 2.5 µg/mL …

Using An Analytical Approach Of The Kuramoto Model To Stimulate 3d Neural Activity Of The Stomach, Morteza Al Rabya

Undergraduate Student Research Internships Conference

No abstract provided.

Optimization Of Dna Extraction From Difficult Sandy-Loam Soils, Anka Colo

Undergraduate Student Research Internships Conference

Ginseng is a high value perennial crop grown for its roots. A four-year cultivation cycle is required to obtain marketable ginseng roots, during which a condition called ginseng replant disease (GRD) develops. GRD is characterized by a severe root rot disease, and prevents the growth of newly planted ginseng in a former ginseng garden1. Microbiome analysis of ginseng garden soil will help our understanding of the formation of GRD and its severity. However, extracting DNA from the sandy-loam soils required for ginseng cultivation is difficult. Commercial kits are either too expensive or not applicable to the large volumes of soil …

Fine-Scale Morphological Divergence Of Wing Trait Variables In Highly Fragmented Populations Of The Bog Copper Butterfly (Lycaena Epixanthe), Jessica L. T. Jeong

Undergraduate Student Research Internships Conference

Habitat fragmentation can adversely affect animal and plant species through subdividing their natural habitats into smaller, more isolated patches. Oftentimes, these isolated groups are subject to reduced dispersal and gene flow, leading to genetic divergence and, consequently, morphological divergence among populations. This study aims to quantify the morphological divergence of the bog copper butterfly, Lycaena epixanthe, between nine isolated bog sites in Algonquin Provincial Park, Ontario, via seven quantitative morphological traits in their wing pattern. Statistical analyses demonstrate significant differences in wing trait measurements between populations. As bog coppers are small, weak fliers with a strict host-plant dependency, it …

Running Behaviour In Impalas In Response To Various Levels Of Predation Threat, Alisiia Glushak

Undergraduate Student Research Internships Conference

No abstract provided.

Stable Hydrogen Isotopes Of Aquatic-Emergent Versus Terrestrial Insects In Southern Ontario, Celina Y. Tang

Undergraduate Student Research Internships Conference

Aquatic-emergent insects are vectors of both contaminants and nutrients, linking the aquatic system to the terrestrial system. Aquatic-emergent insects are high in omega-3 fatty acids that benefit terrestrial aerial insectivores, such as bats and birds. With aerial insectivores on a decline, a contributing factor could be a decrease in the quality of insects. We collected insects from lakeshore and inland locations in Southern Ontario. Insects sampled included bees, wasps, ants, beetles, caddisflies, craneflies, dragonflies, marchflies, mayflies, midges, other flies, and true bugs. Insects’ wings and powdered bodies were then analyzed for stable hydrogen isotopes (d²H) in order …

Functional Characterization Of Arogenate Dehydratase Isoforms In Soybean, Ramtin Sirjani

Electronic Thesis and Dissertation Repository

Phenylalanine flux is partitioned between phenylpropanoid and protein synthesis. The mechanisms behind the metabolic channeling of phenylalanine are largely unknown. Arogenate dehydratase (ADT) enzymes, which catalyze the last and rate-limiting step in the synthesis of phenylalanine in plants, have been shown to interact with the isoflavonoid metabolon in the cytosol. Cytosolic phenylalanine, however, can only be synthesized through prephenate dehydratase (PDT) activity. In this study, putative soybean ADTs (GmADTs) were characterized for their ADT and PDT activity. This was done using complementation assays with two different knockout yeast strains, aro8aro9 and pha2, which lack prephenate aminotransferase and PDT activity, …

The Analysis Of Ginsenosides In Ginseng Garden Soil, Karina Marie Kaberi

Electronic Thesis and Dissertation Repository

American ginseng (Panax quinquefolius L.) produces natural products called ginsenosides. The biggest challenge Ontario commercial ginseng farmers face is ginseng replant disease. To understand the function of ginseng root exudates, ginsenoside accumulation and persistence over time were investigated. Currently, no reliable ginsenoside specific extraction method, characterizing the changes in soil chemistry exists. Ginsenoside extraction protocol optimization was required to determine how ginsenoside composition changed over time. Overall, protocol optimization resulted in a 30% increase in yield of ginsenosides compared to previous extraction protocols. In the ginseng gardens, ginsenoside accumulation occurs slowly and did not reach significantly measurable amounts until the …

Erratum: Publisher Correction: Fear Of Large Carnivores Is Tied To Ungulate Habitat Use: Evidence From A Bifactorial Experiment (Scientific Reports (2021) 11 1 (12979)), Haley K. Epperly, Michael Clinchy, Liana Y. Zanette, Robert A. Mccleery

Biology Publications

No abstract provided.

Dynamics Of The Soil Microbiome In Ginseng Gardens, Megan E. Lambert

Electronic Thesis and Dissertation Repository

Ginseng Replant Disease (GRD) is a syndrome in which ginseng cannot be cultivated in soil previously used to grow ginseng. Since GRD can persist for decades, it severely impacts the Ontario ginseng industry. To better understand the origin of GRD, the impact of ginseng cultivation on the soil microbiome was investigated in bulk soil of three newly planted ginseng gardens in Ontario, from seeding through two years of cultivation. While specific trends in species richness, diversity and composition were unclear, PERMANOVA analyses confirmed that they changed over time. Known GRD-related pathogens, including Ilyonectria mors-panacis and Fusarium oxysporum, were detected in …

Food Caching Decisions In Canada Jays (Perisoreus Canadensis), Robert J. Martin

Electronic Thesis and Dissertation Repository

Food scarce periods pose serious challenges for birds, particularly when those periods coincide with demanding life history stages such as overwintering. For resident birds in the Northern hemisphere, resource scarcity typically occurs simultaneously with winter conditions. In order to combat these compounded stressors, some species cache food to ensure a reliable supply of resources. Food caching is the storing of food items for subsequent retrieval and consumption after some delay. Canada Jays (Perisoreus canadensis) are year-round residents of the North American boreal forest and some high elevation areas in the United States, and cache food to combat resource …

Fear Of Predators In Free-Living Wildlife Reduces Population Growth Over Generations, Marek C. Allen, Michael Clinchy, Liana Y. Zanette

Biology Publications

Data set for article in Fear of predators in free ‐ living wildlife reduces population growth over generations

in

Proceedings of the National Academy of Sciences of the United States of America

Epigenetic Memories And The Evolution Of Infectious Diseases, Geoff Wild

Biology Publications

Genes with identical DNA sequence may show differential expression because of epigenetic marks. Where epigenetic marks respond to past conditions, they represent a form of “memory”. Despite their medical relevance, the impact of memories on the evolution of infectious diseases has rarely been considered. Here we explore the evolution of virulence in pathogens that carry memories of the sex of their previous host. We show that this form of memory provides information about the sex of present and future hosts when the sexes differ in their pathogen’s transmission pattern. Memories of past hosts enable the evolution of greater virulence in …