Biology

Permanent URI for this collectionhttps://hdl.handle.net/10315/27613

Browse

Now showing 1 - 20 of 362

Access status: Open Access ,
Declining Ice Duration and Changing Ice Quality Drive Key Under-Ice Ecological Changes in Wisconsin Lakes
(2025-11-11) Sandrock, Phoenix Kieran; Sharma, Sapna
Lakes are rapidly losing ice cover. We expect that ice loss will have widespread ecological consequences, but these consequences are poorly understood, particularly over long temporal scales. Here, we ask: how do changing ice duration and ice quality influence under-ice photic depth, water temperatures, dissolved oxygen concentrations, and chlorophyll a concentrations? We analyzed winter data from 11 lakes across Wisconsin, USA, with time-series extending from 1982 to 2023. Shorter ice durations and less snow were associated with deeper photic depths, colder under-ice water temperatures, and higher dissolved oxygen saturations. Snow and ice conditions were significantly related to chlorophyll a concentrations; however, the relationship was mediated by nutrient concentrations. We suggest that the drivers of under-ice ecology are as complex as those of the open water season and advocate for the use of integrative models to understand the future of ice-covered lakes.
Access status: Open Access ,
Reclaiming Autumn in Limnology: Evidence of Shifting Autumn Phenology and Impacts on Winter Conditions and Cross-Seasonal Lake Dynamics
(2025-11-11) Ferrato, Faith Renee; Sharma, Sapna
Autumn remains understudied in limnology, despite its recognized ecological importance in other disciplines. In this thesis, we addressed the need for greater integration of autumn into limnological research (Chapter 1) and demonstrated how climate-driven shifts in autumn phenology affect ice formation and winter thermal conditions (Chapter 2). Using 37–50 years of data from 47 Finnish lakes, we found that autumn surface waters have warmed significantly, resulting in widespread delays in ice formation. Delayed ice formation was associated with colder bottom under-ice temperatures. Stronger autumn winds and larger lake size were also associated with colder under-ice conditions through their influence on pre-freeze mixing and heat loss. Furthermore, higher maximum summer surface water temperatures were observed in years with later ice-on dates. As climate change continues to disrupt seasonal patterns, a greater focus on autumn will be critical to effectively predict the impacts of warming on ecosystem functioning of northern lakes.
Access status: Open Access ,
Examining Sex Differences of Adipose Endothelial Cells and the Effects of Foxo1 Deletion
(2025-11-11) Pislaru, Alexandra; Haas, Tara
During obesity, adipose tissue undergoes significant remodeling to store excess energy. Adequate vascular growth is required for adipose expansion, which ensures proper oxygen and nutrient supply and prevents insulin resistance and metabolic disease. Thus, coordinated angiogenesis is critical for metabolic health during obesity. Transcriptomic analysis of adipose endothelial cells (ECs) from high-fat fed mice revealed that female ECs displayed a proliferative and chromatin-remodeled profile, while male ECs were enriched in inflammatory and senescence-associated signatures. Similar sex differences were observed in aging ECs. To assess the influence of sex hormones, a gonadectomy model was used. Surprisingly, the loss of gonadal hormones increased capillary density despite reduced levels of VEGFA in the adipose microenvironment. However, gonadectomy had no long-term effect on EC metabolism in culture, though direct estradiol stimulation did increase mitochondrial ATP production. One candidate contributor of sex differences is the endothelial quiescence-inducing transcription factor forkhead box O1 (FoxO1), which is more highly expressed in female ECs despite higher angiogenic activity. FoxO1 knockdown or inhibition in females led to a dysfunctional EC phenotype which was marked by inflammation, oxidative stress, impaired mitochondrial function, and DNA damage. These endothelial disturbances caused by FoxO1 loss were accompanied by lower capillary content in the females, a response not mirrored in males. Overall, these studies demonstrate that female ECs exhibit a healthier phenotype under obesogenic conditions, a trait that appears to be largely independent of sex hormones. Instead, FoxO1 emerges as a major contributor to this protective and resilient female endothelial profile.
Access status: Open Access ,
Structural and RNA-Binding Characteristics of Three Yeast LA Motif Domains
(2025-11-11) Pacheco, Evan Moniz; Donaldson, Logan
La-related proteins (LARP) are a conserved class of RNA-binding proteins that function in RNA metabolism, including mRNA stabilization, translation regulation, and non-coding RNA processing. In humans, La-related protein 1 (LARP1) regulates translation and stability of 5′ terminal oligopyrimidine (TOP) tract-containing mRNAs linked to cell growth and proliferation. Although its role as a downstream effector of the mTORC1 pathway is established, the molecular interactions of LARP1 and yeast homologs remain poorly defined. This thesis examines the structure–function relationship of the La motif domain (LaM) in yeast proteins Slr1p, Slf1p, and Sro9p using isothermal titration calorimetry (ITC), circular dichroism (CD), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC). Findings show these proteins share conserved features and bind RNA and ligands with high affinity (low micromolar Kd). NMR line broadening observed for Slf1p–RNA interactions suggests conformational sampling. Collectively, these results advance understanding of conserved mechanisms underlying LARP1-mediated translational regulation.
Access status: Open Access ,
The Vestibular System's Influence on the Perceived Duration of Lights, Sounds, and Touches
(2025-11-11) Ghasemi, Fatemeh; Harris, Laurence
Time perception is essential to human experience, but factors like microgravity can alter it (Navarro Morales et al., 2023). To explore the role of gravity, I compared time perception in standing and supine postures. Participants (n=124) judged whether stimuli (light, sound, tactile vibration) lasted longer or shorter than 1 second. In Experiment 1, participants judged light duration; in Experiment 2, sound; in Experiment 3, tactile vibration; and in Experiment 4, visual duration with and without disruptive galvanic vestibular stimulation (dGVS). Results revealed that light and tactile stimuli were perceived as longer than auditory stimuli, but the perception of auditory and tactile durations was unaffected by posture. However, visual duration was perceived as significantly longer when supine (45ms) or with dGVS (66ms). These findings suggest that the vestibular system influences visual time perception, with disruptions slowing the perception of time.
Access status: Open Access ,
ALY688 Protects Against Ferroptosis Via Nrf2 Activation in Skeletal Muscle
(2025-11-11) Haetanurak, Photsathorn; Sweeney, Gary
Ferroptosis is a regulated form of cell death that is characterized by excessive lipid peroxidation. Arachidonic acid (AA), a polyunsaturated fatty acid (PUFA), can be incorporated into cell membrane phospholipids, thereby increasing their susceptibility to oxidative damage and ultimately ferroptosis. In this study, AA was found to enhance susceptibility to ferroptosis in both rat L6 cells and human iPSC-derived skeletal muscle cells. In the presence of AA, cells responded to iron overload (IO) with elevated oxidative stress, total cellular lipid peroxidation and mitochondrial lipid peroxidation, culminating in more ferroptotic cell death. These effects were significantly attenuated by ALY688, an adiponectin receptor agonist. We observed that ALY688 activated Nrf2 signaling in both L6 and iPSC-derived skeletal muscle cells and that the cytoprotective effect of ALY688 was abolished by ML385, an Nrf2 inhibitor. Together, these findings identified that AA increased skeletal muscle cell susceptibility to detrimental effects of iron and established that ALY688 mitigated the combined effects of AA and IO via an Nrf2-dependent mechanism.
Access status: Open Access ,
Spatio-Temporal Variation in Ringed Seal (Pusa Hispida) Density and Habitat Use in the Last Ice Area
(2025-11-11) MacLean, Roxanne Dawn; Thiemann, Gregory W.
The Arctic is experiencing warming at a rate approximately four times faster than the global average, contributing to precipitous declines in the extent, thickness, age, and seasonal duration of sea ice. The full effects of these rapid changes in sea ice habitat on the Arctic marine ecosystem remain unknown, especially in the High Arctic where ecological research has been limited due to its remoteness. Ringed seals (Pusa hispida) are an abundant ice-associated pinniped species with a habitat range spanning the circumpolar region, making them an ideal study species for exploring ecological changes under changing environmental conditions. Using observations from aerial surveys, this thesis provides the first study on spatio-temporal variation in ringed seal density and habitat use in their northern most range in the Canadian High Arctic, highlighting the importance of bathymetry and marine terminating glaciers to the summer habitat use of ringed seals in the Last Ice Area.
Access status: Open Access ,
Investigating the Anti-Inflammatory Mechanism of the Adiponectin Receptor Agonist, ALY688, in Iron Overload-Induced Macrophage Activation
(2025-11-11) Zhang, Bojun; Sweeney, Gary
Chronic inflammation, driven by fa tors such as iron overload, contributes to metabolic, cardiovascular, and degenerative diseases. Excess iron promotes pro-inflammatory cytokines release and increased production of reactive oxygen species (ROS) in macrophages via transcription factors, such as IRF and NF-κB. This study investigated whether ALY688, an adiponectin receptor agonist, mitigate iron-induced inflammation. Using ferrous sulfate (FeSO₄) treated RAW 264.7 macrophages, I found that ALY688 markedly reduced the activation of both NF-κB and IRF pathways, suppressed ROS levels, and reversed the expression of inflammatory and antioxidant genes. Iron overload significantly upregulated pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) and oxidative stress-related genes (NOX2), while downregulating anti-inflammatory mediators such as IL-10. Together, these findings support a regulatory role of ALY688 in attenuating iron-induced oxidative stress and inflammation in macrophages, suggesting that ALY688 may serve as a promising therapeutic candidate for iron overload-associated inflammatory disorders.
Access status: Open Access ,
Proteomic Study Of The Ubiquitin E3 Ligase HUWE1 Interaction With Ubiquitin And ADP-Ribose Modified Proteins
(2025-07-23) Nader, Nour; Sheng, Yi
Ubiquitination and ADP-ribosylation are important post-translational modifications (PTMs), especially in cellular response to DNA damage. HECT, UBA, and WWE domain containing E3 ubiquitin protein ligase 1 (HUWE1) is an important ubiquitin E3 ligase involved in many cellular processes. HUWE1 contains regions involved in substrate interaction and domains for PTM recognition. Specifically, HUWE1 WWE and tandem ubiquitin-binding motif (tUBM) domains interact with ADPr/iso-ADPr and ubiquitin, respectively. However, the interaction between these domains and cellular ADP-ribose and ubiquitin and potentially substrate interactions are not well investigated. Thus, this project aimed to investigate the interactome of HUWE1 WWE and tUBM domain, focusing on their ability to bind proteins modified by mono-ADP-ribose (MAR)/poly-ADP-ribose (PAR) and ubiquitin using GST pulldown assay. First, using Western blot and confocal microscopy, distinct dynamics of ubiquitination and ADP-ribosylation were observed in response to different DNA damage treatments. Second, the study demonstrated that the WWE-tUBM domain interacts with both cellular ADP-ribose and ubiquitin. Moreover, through a proteomic approach using affinity mass spectrometry, this study identified novel proteins that interact with the WWE and tUBM domains following Ultraviolet (UV) induced DNA damage. Together, the findings of this project contribute to a better understanding of how HUWE1 engages with its substrates and highlight the role of WWE and tUBM domains and their ability to recognize PTMs in mediating these interactions.
Access status: Open Access ,
Genome Wide Analysis Of Admixture In Apis Mellifera Intermissa
(2025-07-23) Ritchie, Caroline Rose; Zayed, Amro
Unraveling the evolutionary history of Apis mellifera reveals how populations have adapted to diverse environments, resisted disease, and responded to human influence. An admixed population of A. m. intermissa in Morocco has sparked debate over the dispersal routes of A. mellifera and the origin of the European (M) lineage. Yet, despite its identification, the genomic consequences of this admixture remain largely unexplored. We analyzed global and local ancestry, estimated admixture timing, and assessed genetic diversity in this A. m. intermissa population. Our findings reveal recent admixture, occurring ~14 generations ago, with genome-wide diversity reflecting an intermediate value between progenitor lineages. Notable regions on chromosomes 7 and 11 showed high enrichment for M lineage ancestry. Functional enrichment and prior studies suggest these regions influence detoxification, immunity, development, and hormonal regulation. Four QTLs with 18 loci further support M lineage contributions to Varroa destructor resilience. These findings reveal the functional role of M lineage ancestry in North African Apis mellifera populations and offer a framework for further exploring the genomic outcomes of admixture.
Access status: Open Access ,
Probing the Activity of Fmta, A Novel Esterase in Staphylococcus Aureus, in Vitro and in Vivo Through Mutagenesis.
(2025-07-23) Sengupta, Saptarshi; Golemi-Kotra, Dasantila
The versatile bacterium Staphylococcus aureus (S. aureus) resides within the human microbiota, manifesting commensal and pathogenic characteristics. The emergence of methicillin-resistant S. aureus (MRSA) underscores the global challenge of antibiotic resistance. FmtA, a protein exhibiting structural similarities and distinct features relative to Penicillin-binding proteins (PBPs) within the Penicillin penicillin-recognizing proteins (PRPs) umbrella, significantly contributes to the S. aureus antibiotic resistance mechanism. FmtA acts on Wall Teichoic Acid (WTA), an abundant poly-ribitol polymer in S. aureus peptidoglycan, where FmtA removes D-Alanine (D-Ala) from WTA, which is esterified post-synthesis where the D-alanylation level in WTA is an important contributor in S. aureus antibiotic resistance and physiology. Previous research addressed the structural intricacies of FmtA and based on the positioning of key amino acid residues, it was proposed that the enzyme's active site has evolved to specifically bind WTA. It was further hypothesized that FmtA has adapted to carry out D-amino esterase activity against WTA, highlighting its specialized functional evolution. In this study, I investigate the role of specific amino acid residues present in the active site of FmtA, focusing on their interactions with WTA using both in vitro and in vivo approaches. Given the overall negative charge of WTA, derived from its phosphodiester backbone, it is a target for cationic polymers like Branched Polyethyleneimine (BPEI). Previous research has shown that BPEI binding to WTA creates a steric hindrance, disrupting the function of penicillin-binding proteins (PBPs) such as PBP4 in Staphylococcus aureus and PBP2a in Staphylococcus epidermidis. This disruption impacts key bacterial physiological processes, including cell division, virulence, and peptidoglycan biosynthesis. My findings reveal that BPEI can compete with FmtA for WTA binding, though less effectively, leading to partial inhibition of FmtA's enzymatic activity. Additionally, BPEI binding affects the physiological activities of S. aureus, including biofilm formation, which is typically mediated by FmtA. These results suggest that while BPEI hinders FmtA's interaction with WTA and its subsequent enzymatic function, it does not completely block FmtA activity.
Access status: Open Access ,
Does Motion Parallax Improve Communication Efficiency in Video Chats?
(2025-07-23) Funkhouser, Ashley Jayne; Troje, Nikolaus
As video communication has become more prevalent in our day-to-day lives, it becomes evident that face-to-face communication vastly outclasses video chat in terms of peer communication. Motion parallax is a perceptual effect that arises when an observer moves relative to their surroundings, or their surroundings move relative to them, causing nearby objects in their visual field to appear to move more quickly than distant objects. This relative motion provides a depth cue that the brain can use to estimate the relative distances and orientations of the objects. Directionality is a mutual understanding of the distance and orientation of people in 3D space (Troje, 2023). Previous studies have found that motion parallax is important in determining the direction of objects (Wang & Troje, 2023). Motion parallax can help provide directionality in day-to-day life, including aiding with nonverbal cues such as pointing or turning one’s head. This study examines whether adding motion parallax to video chat with avatars can enhance communication efficiency, as indicated by performance on an instruction task. Many nonverbal cues like mutual gaze, pointing, and eye contact rely on directionality to function accurately. Video chat can create misleading cues due to the lack of motion parallax, causing misunderstandings (Troje, 2023). This study found that the use of motion parallax while video chatting did not enhance performance on a shared task between two subjects, relative to the control. Further research is required to clarify the relationship between motion parallax and communication efficiency in video chat with avatars.
Access status: Open Access ,
Exploring the Effects of Shared Home Ranges on Human-Wildlife Interactions, Parasite Overlap, and Stress Responses in Vervet Monkeys (Chlorocebus Pygerythrus) in East Africa
(2025-07-23) Upadhayay, Pooja; Schoof, Valerie
As human populations expand and encroach upon natural habitats, boundaries between human settlements and wildlife become increasingly blurred. These shared spaces influence human-wildlife interactions and elevate the risk of zoonotic disease transmission. This dissertation investigates the consequences of overlapping home ranges for human-wildlife conflict, parasite community structure, and physiological and behavioral stress responses in vervet monkeys (Chlorocebus pygerythrus). Chapter 2 compares human-wildlife conflicts (HWCs) at sites in Uganda and Kenya, analyzing how socioeconomic factors shape local responses. Respondents reported both positive and negative effects of living near a research station or conservancy, with significant variation in conflict severity and frequency. Chapter 3 examines gastrointestinal parasite communities in sympatric hosts—humans, dogs, livestock, and vervets—around Lake Nabugabo, Uganda. Findings revealed overlapping parasite taxa across species, suggesting shared transmission pathways. Chapter 4 uses a parasite removal experiment (deworming and natural reinfection) to assess how gastrointestinal parasites affect vervet monkey fecal glucocorticoid metabolites (fGC) and behaviors. Reinfection elevated fGC levels and altered behaviors, though not always in predicted ways. This interdisciplinary research integrates ecological, parasitological, and ethological approaches to understand how habitat sharing influences disease ecology and stress in wildlife. The findings underscore the complexity of human-wildlife coexistence and highlight the importance of incorporating both ecological and social dimensions into conservation and public health strategies.
Access status: Open Access ,
The Development of the Functional Dissociation of Perception and Action
(2025-07-23) Ahmad, Zoha; Freud, Erez
Humans rely on their visual system to navigate and interact with the world, utilizing two functionally distinct cortical pathways: the ventral pathway, responsible for visual perception, and the dorsal pathway, which supports visuomotor actions. While the functional dissociation between these behaviours has been extensively studied in adults, its developmental trajectory and susceptibility to neurodevelopmental conditions is not as well-understood. This dissertation investigates the dissociation between perception and action in pediatric and adult populations with atypical neurodevelopment, focusing on three experimental studies. The first study examines a pediatric patient, TC, who underwent a unilateral cortical resection impacting both the dorsal and ventral pathways. Despite intact perceptual abilities, her visuomotor behaviors were markedly impaired, highlighting differential developmental trajectories of the two pathways and the dissociation between perception and action. The second study investigates children with amblyopia, a developmental visual disorder, and finds a reduced perception-action functional dissociation compared to neurotypical controls. This suggests that atypical visual experience disrupts the functional specialization of the pathways early in life. The final study focuses on adults with Autism Spectrum Disorder (ASD) and reveals reduced perception-action dissociation in two different contextual conditions. Together, these studies provide a detailed examination of how neurodevelopmental conditions influence the emergence of perceptual behaviors, visuomotor behaviours and the dissociation between these functions. These investigations confirm the sensitivity of visuomotor behaviours to atypical development and show that the dissociation between perceptual and visuomotor functions is disrupted under a range of neurodevelopmental conditions.
Access status: Open Access ,
Nutritional Ecology of Wild Bees: How Pollen Macronutrient Composition Shapes Development and Survival
(2025-07-23) Stephen, Khara Nyesha Whytnei; Rehan, Sandra
Bees rely on diverse floral resources to meet their nutritional needs, yet habitat loss, urbanization, and agricultural intensification are altering pollen availability and composition. Understanding the macronutrient profiles of pollen is central for pollinator health, as protein, lipids, and essential fatty acids influence bee development and survival. This thesis explores the nutritional composition of pollen from various plant species and its implications for bee health. Chapter I investigates the macronutrient content of 57 pollen species native to North America, revealing significant variation in non-esterified fatty acids (NEFAs), amino acids (AAs), and protein-to-lipid (P:L) ratios. Asteraceae pollen was particularly rich in essential amino acids, while mixed diets provided a balance of nutrients necessary for bee health. Chapter II examines how pollen macronutrient composition influences larval development in the small carpenter bee (Ceratina calcarata). Experimental rearing on black poplar (Populus nigra) and dandelion (Taraxacum officinale) pollen demonstrated that protein-rich arboreal pollen significantly enhanced bee growth, survival, and developmental rates. Bees on dandelion pollen alone exhibited delayed growth and reduced body size, while mixed diets mitigated nutritional stress. This research highlights the importance of nutritional diversity in pollen sources, emphasizing the role of tree pollen as an overlooked resource for pollinator conservation. As habitat loss and climate change continue to threaten pollinators, ensuring access to high-quality, nutritionally diverse floral resources may be key to sustaining bee populations and promoting ecosystem resilience.
Access status: Open Access ,
The Removal of D-Alanine from the Cell Wall Teichoic Acids of Staphylococcus Aureus by the fmtA Protein Drives Strain-Specific Viability Alterations Under Environmental Stress Conditions
(2025-07-23) Capota, Matthew; Golemi-Kotra, Dasantila
Antibiotic resistance of highly infectious Staphylococcus aureus makes eliminating this microorganism increasingly difficult, contributing to hospitalizations and severe infections worldwide. Wall teichoic acids (WTAs), linked to the bacterial cell wall, play key roles in resistance, cell lysis, and survival. WTAs are modified by the addition of D-alanine (D-Ala), which helps control bacterial surface charge and antibiotic resistance. S. aureus naturally cleaves D-Ala using the enzyme FmtA. We investigated whether purified FmtA could influence bacterial growth and survival by removing D-Ala from WTAs in vivo under favourable or unfavourable environments. Our findings confirmed that FmtA removes D-Ala from S. aureus and other Gram-positive bacteria. While S. aureus viability remained stable under favourable conditions, strain-specific responses emerged under variable stress. Notably, methicillin-resistant strains became more sensitive to oxacillin when exposed to FmtA. These results suggest that targeting WTA modifications could be a strategy to alter S. aureus viability under specific stress-inducing conditions.
Access status: Open Access ,
Biochemical and Structural Characterization of the S. Pombe La-Related Protein 1 (Slr1p)
(2025-07-23) Mansouri-Noori, Farnaz; Bayfield, Mark
La and La-related proteins (LARPs) are conserved RNA-binding proteins that share a characteristic La motif (LaM) and have important functions in RNA metabolism. Several LARP families exist where members possess specific domains that allow for binding to unique substrates. The LARP1 family, which includes a DM15 domain, binds a cohort of mRNAs encoding factors involved in the process of mRNA translation. These mRNAs contain a sequence of 5-15 pyrimidines in their 5′UTRs, immediately following the m7G cap, and are characterized as 5′ terminal oligopyrimidine (5′TOP) mRNAs. The DM15 domain of human LARP1 has been suggested to specifically recognize this motif, thereby affecting the translation and stability of 5′TOP mRNAs. However, the specific function of LARP1 in this context remains unclear. Intriguingly, the 5′TOP motif does not exist in yeast, and LARP1 orthologs in this system lack the characteristic DM15 domain. In this work, we characterize the S. pombe La-related protein 1, Slr1p, as an RNA-binding protein with conserved functions relative to other LARP1 orthologs. Through proteomic and transcriptomic studies, we show that Slr1p regulates the translation and stability of mRNAs that encode ribosomal proteins and other components of the translational apparatus in S. pombe. We further identify a 5′ Proximal AC-rich (5′PAC) motif, residing close to the start AUG, in these mRNAs and propose that they represent a cohort of proto-5′TOP mRNAs. Through structural analyses and mutagenesis studies, we show that the LaM of Slr1p is responsible for binding to the 5′PAC RNA motif, where mutagenesis of a single amino acid in our characterized binding site disrupts this interaction. We further demonstrate that Slr1p plays a role in adaptation to translation stress and that its phosphorylation status may allow for several functional states. Our findings are consistent with the conservation of LARP1 function across eukaryotes, and suggest that the involvement of this protein family in ribosomal protein mRNA translation and stability is influenced by a more fundamental LaM-dependent form of LARP1 regulation that is utilized in S. pombe.
Access status: Open Access ,
Effects of Anthropogenic Light and Noise on Anti-Predator Behaviour and Reproductive Success of an Urban Nesting Passerine
(2025-07-23) Scialla, Ileana; McKinnon, Laura
Species inhabiting urbanized habitats are continually facing challenges as urbanization intensifies. For urban birds, noise pollution may affect acoustic communication, and light pollution may affect circadian rhythms, yet very little research has been conducted in these areas. I investigated the effects of noise and light pollution on daily nest survival and anti-predator behaviour of American robins (Turdus migratorius) Toronto, ON Canada over 2 summers by monitoring nests and by using an observational and experimental approach. Anti-predator behaviours were influenced by light and noise pollution, but nest survival was unaffected. Higher levels of anthropogenic light and noise had no effect on nest survival; even experimentally increasing light levels at nests had no effect. Higher light and noise pollution did increase the frequency of anti-predator behaviours by nesting birds. Lastly, in areas of higher noise pollution robins were less likely to respond to experimental predator calls.
Access status: Open Access ,
Tethered To Telomeres: Characterizing The Form And Dynamic Elasticity Of Tethers In Anaphase Crane-Fly Spermatocytes
(2025-04-10) Economopoulos, Demetra; Connor, Steven
Elastic tethers connect sister chromosomes during anaphase in a broad range of animal cells, likely aiding in communication and coordination of movement. Calyculin A prevents dephosphorylation of tethers by protein phosphatase 1 (PP1) and, consequently, causes them to remain elastic throughout anaphase, resulting in backward movement. In my thesis experiments, I further explore the composition and behaviour of tethers. I expand upon existing research with Calyculin A, elucidating an optimal working concentration of 10 nM for investigating the reversibility of this drug on backward movement when rinsed out at various stages. I show that PP1 is critical during the onset of anaphase and that backward movement is not readily reversible. I also support the existing notion that tethers are made of titin, disproving the hypothesis that tethers are made of DNA. These contributions further enhance our understanding of tether composition and regulation during a central mechanistic phase of cell division.
Access status: Open Access ,
Finding Common Ground: Methods For Sustaining Citizen Science Engagement That Increase Indigenous Plant Biodiversity In Southwestern Ontario
(2025-04-10) Bava, Julia Maria; Bazely, Dawn R. A.
Nature-based solutions to address biodiversity loss require supports that reach beyond government grants. The Conservation Impact Bond (CIB) developed by Southwestern Ontario regional conservation charity, Carolinian Canada Coalition, is an example of a novel financial tool to incentivize biodiversity conservation by supporting citizen science. My research evaluated Carolinian Canada’s In The Zone Tracker and its allied programs. A systematic review of the literature about Canadian citizen science projects provided context. (1) The ITZ Program reversed plant biodiversity loss at a local level through planting projects that generated a self-reported increase in native species. (2) Information about citizen science projects was difficult to discover. Academic research into citizen science projects published in peer-reviewed literature creates a more permanent record than web-based, grey literature. (3) Citizen science projects do not necessarily improve science literacy. Rather, the ITZ tracker helped people to find common values and make positive, evidence-informed differences in their communities.

Browse

Recent Submissions