Biological Sciences Undergraduate Works

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Open Access
Alternative BNIP3 splicing in alveolar rhabdomyosarcomal cells
(2023-04) Fernando, Amy; Whyard, Steve (Biological Sciences); Ghavami, Saeid (Human Anatomy and Cell Science); Gordon, Joseph; Wilkins, Olivia
Several cellular phenotypes drive tumorigenesis in alveolar rhabdomyosarcoma. These phenotypes may be attenuated via treatment with non-steroidal antiinflammatory drugs, like aspirin, tolfenamic acid, and indomethacin, which interfere with intracellular prostaglandin synthesis and induce cell death. Recent data suggest that this mechanism may be mediated by differential splicing of the cell death gene BNIP3, such that full-length BNIP3 could promote cell death, while short BNIP3 could inhibit it. Additional data indicate that oncogenic cytokines from the TGF-β family may also be involved in this mechanism. This honours thesis examines whether indomethacin alters cell death, BNIP3 splicing, and other alveolar rhabdomyosarcoma phenotypes. To assess this, RT-PCR and fluorescent imaging assays were performed on the RH30 cell line. Results of these experiments indicate that a 2.0 μM concentration of indomethacin alters the cell death phenotype. However, they also provide preliminary evidence that the expression levels of full-length and short BNIP3 are unchanged. Accordingly, drug treatments did not change calcium signalling pathways. Furthermore, this text examined the role of TGF-β cytokines in this molecular pathway. To help establish the role of TGF-β in alveolar rhabdomyosarcoma, a statistical analysis of a previously generated secretome dataset was performed. It determined that the three TGF-β isoforms are differentially secreted in alveolar and embryonal rhabdomyosarcoma. However, qRT-PCR results indicate that indomethacin exposure does not change TGF- β1 expression. Collectively, this thesis provides preliminary evidence that indomethacin exposure induces cell death in RH30s independently of alternative BNIP3 splicing.
Open Access
An Investigation of Knowledge Retention Using Two-Stage Exams in Undergraduate Biology
(2024-07-04) Judge, Abby
Although active learning is typically thought of as an in-class experience, this concept can be further applied to assessments as well. Two-stage exams allow for the unique experience of students working collaboratively during examinations, following the completion of the individual stage. Although two-stage exams have been shown to improve student learning gains, the effects of two-stage exams on retention of course content remains variable. I examined the effects of two-stage exams on knowledge retention at various Bloom’s level (Remember, Understand, and Apply) to determine whether two-stage exams promote knowledge retention at various levels of cognitive thinking. A two-stage in-class test followed by the re-testing of questions answered individually or in groups at subsequent time points (5, 48, and 85 days) allowed testing for knowledge retention. Our results indicate that group questions improve knowledge retention at relatively long time periods across all Bloom’s levels while also promoting retention at more complex Bloom’s levels at intermediate and relatively long time periods. Additionally, our analysis reveals that an average of 40% of individual only questions are forgotten by the final exam, while only an average of 19.5% of group questions are forgotten by the final exam. These results indicate that two-stage exams promote the ability to retain complex information at relatively long time periods.
Open Access
Arthropod Diversity Within The Three Sisters Cropping System
(2024-07-04) Ferch, Tessa; Roth, Jim (Biological Sciences); Markham, John (Biological Sciences); Bobiwash, Kyle; Worley, Anne
The Three Sisters is an indigenous cropping method that dates back hundreds of years. It is comprised of the simultaneous planting of corn, bean, squash, and sometimes sunflower. However, there has been no published research into arthropod communities and interactions with this cropping system. My study examined arthropod abundance and taxa to the family level at three areas: uncultivated, fields planted with The Three Sisters, and field edges. This was done at three sites in Manitoba: Ian N. Morrison Research Farm near Carman, Glenlea Research Station near Glenlea, and Brokenhead Ojibway First Nations Reserve. I placed 8 sticky cards within each area at each site starting in July 2023, and had 4 bi-weekly sampling rounds. The number of samples collected and processed was 288. I conducted a perMANOVA test, and ran multiple negative binomial generalized linear mixed models, testing the abundance and number of taxa present in relation to the site, area type, date, colour, and using trap number as a random effect. All sites were significantly different from each other. Glenlea had the highest diversity, and Carman had the least diversity. The uncultivated areas differed from both the field and edge areas, and the fields and edges also differed from each other at all sites. The field and edges had higher diversity than the uncultivated areas. The most important finding of my study was that The Three Sisters is an agricultural method that can allow for higher diversity of arthropods than uncultivated areas.
Open Access
Characterization of the oxygen binding properties of hemoglobin from the ruby-throated hummingbird (Archilochus colubris)
(2024-07-04) Patel, Suchita; Signore, Anthony (Biological Sciences); Fraser, Kevin (Biological Sciences); Campbell, Kevin
Weighing only between 2.5 and 4.8 g, the ruby-throated hummingbird (A. colubris) has one of the highest known mass-specific metabolic rates among birds. Despite this, there is a lack of available data on the oxygen binding properties of their hemoglobin (Hb). Here I measured the effect of allosteric effectors, pH and temperature on the O2-affinity (defined as the O2 partial pressure required for 50% Hb O2 saturation; P50) of ruby-throated hummingbird Hb, while also estimating their Hb buffering capacity. A comparison of Hb-O2 affinity (i.e. P50 values) between A. colubris and its sole congener, the black-chinned hummingbird (A. alexandri), revealed differences likely attributed to two β-chain amino acid substitutions. Under treatment conditions resembling the natural physiological state of hummingbird blood, A. colubris exhibited a similar Bohr effect (-0.401) and buffering capacity (4.88 mol H+ mol Hb4-1 pH-1) to those of other hummingbird species, though both variables were among the lowest values previously reported for birds. Nonetheless, the low buffering capacity is modelled to enhance the efficiency of their (relatively low) Bohr effect and may enable a high blood [Hb], which together with a relatively low blood O2 affinity is shown to markedly increase tissue O2 delivery. I also found that O2 binding of A. colubris Hb was thermally insensitive under natural physiological conditions. This thermal insensitivity could help ensure adequate O2 delivery both during and upon arising from torpor, while minimize heat loss at the lungs. These findings highlight the various O2 binding properties of A. colubris that together facilitate the efficient delivery of O2 to the tissues irrespective of temperature.
Open Access
Circadian Patterns of Flight in a Long-Distance Migratory Songbird
(2024-07-05) White, Trina; Davoren, Gail (Biological Sciences); Fraser, Kevin
Migration is a common strategy in many different animal taxa, including birds. Most migratory songbirds migrate mainly at night (i.e., nocturnal migrants), with some species migrating primarily during daytime (i.e., diurnal migrants). Some birds can even combine nocturnal and diurnal flights, but these tend to be associated with barrier crossings (e.g., long overwater flights). Whether diurnally migrating songbirds also incorporate night flights into other periods of their spring migrations despite a lack of migration barriers has not been investigated. Further, we lack a precise understanding of the influence of specific environmental conditions on day or night flight behaviour. We investigated circadian patterns of flight in purple martins (Progne subis), a long-distance migratory songbird that journeys between nonbreeding areas in South America and breeding sites in eastern North America. We used direct-tracking (GPS loggers) of individual spring migrations to quantify the daily timing of flights, flight speed, flight distance, and altitude as well as whether these factors were associated with temperature. Birds were tagged with GPS loggers in Winnipeg, Canada, which collected location and altitude every two hours during spring migration. We used Movebank to align location data with average local temperature. We found that martins migrated mainly during daylight, but surprisingly, 15% of flights overland occurred during the night. The average speed for daytime and nighttime flights was similar. We found that neither temperature nor timing of flights influenced flight speed and distance travelled, but flights at higher altitudes were associated with longer flight distance and faster speeds. Our results suggest that a species classified as a diurnal migrant routinely makes night flights overland that are not associated with crossing known migratory barriers. Further studies could increase the sample size of birds and the number of usable GPS fixes, which would allow us to track birds as close to their breeding grounds in temperate areas as possible.
Open Access
Comparing the Rates of Adaptive Change in Species Across Biogeographic Gradients
(2023-04) Bourrier-Vince, Ava; Fraser, Kevin (Biological Sciences); Jeffries, Kenneth (Biological Sciences); Garroway, Colin
The process of adaptive evolution allows a species to persist with specific traits tailored to their environment. The rate at which a population adapts can change based on the varying environmental abiotic and biotic factors of their location. Environmental characteristics such as the amount of available energy, elevation, temperature and degree of human disturbance thus affect the rates of adaptive evolution across biogeographic gradients. In this study, I used data on adaptive rates for terrestrial species and aimed to determine if the rates of adaptive evolution showed patterns related to spatial biogeographic patterns and environmental factors such as elevation, evapotranspiration, precipitation and temperature. Additionally, I tested whether the rates of adaption changed based on these specific environmental factors and a human density. The results of my data analysis detected that the rates of adaptation showed good variation in relation to spatial scale patterning but no significant correlation patterns between the tested environmental variables and the rates of adaptive evolution were detected. This result did not support my hypothesis that the rates of adaptive change would vary through space with environmental gradients. Many potential factors may have caused this inconclusive result. Further research into this topic would be useful to understand and predict the adaptive evolution of species’ in varying environmental gradients. I propose that studies on this data should aim to utilize more of the available samples within this public dataset such as the aquatic species. Additionally, further research may benefit from narrowing the study size based on location or taxa for significant relationships to be accurately detected.
Open Access
Determining the influence of migratory stopover timing and movement on plant seed dispersal by a short-distance migratory songbird, the American robin, Turdus migratorius
(2024-07-05) Sturch, Tamara; Fraser, Kevin
Animals disperse approximately 50% of seeds worldwide and could assist plants in shifting their distribution in the face of climate change. However, seed dispersal by animals is understudied particularly in temperate areas. American robins (Turdus migratorius) are migratory thrushes which have a frugivorous diet in the fall and may be important seed dispersers. Nineteen American robins were fitted with GPS tracking units at Assiniboine Park, Winnipeg, Manitoba during their fall migration in 2022. The GPS units provided live location data for the birds every 6 hours. This data was used to investigate the seed dispersal potential of American robins during their fall migration by examining the time spent and distance travelled while at stopover, as well as the use of urban versus rural habitats. Fecal samples collected at capture were used to identify the seeds of plant species these robins had consumed and therefore may disperse. I found that individual robins spent 15 to 33 days at fall migratory stopovers (an average of 26.64 days ± 4.95) and travelled extensively at stopovers (29-320 km; average 101.68 km ± 84.95) before continuing migration. Birds made use of both urban and rural habitats while at stopovers. I also found that fecal samples contained both native and non-native seed types, with Malus sp. making up most (62.71%) of the seeds in the samples. Overall, my results show that American robins have the potential to be important dispersers of native and non-native seeds across both rural and urban habitats, due to the large amount of time and distance travelled at fall migratory stopovers. Future studies should evaluate the viability and recruitment of seeds that have been dispersed by robins and examine the movements of American robins during fall stopovers originating from both urban and rural populations.
Open Access
Effects of timing of burlap provision on piglet behaviour, welfare, and performance
(2024-07-05) Penner, Amber; Davoren, Gail (Biological Sciences); Yang, Chengbo (Animal Science); King, Meagan; Waterman, Jane
Many factors contribute to high stress at weaning in commercial pigs. Increased stress can lead to increased aggressive behaviours such as tail biting, displacements, and belly nosing. Enrichment, such as burlap, may provide an outlet for stress, providing a positive source of enrichment and allowing piglets to perform natural behaviours. The first objective of this study was to determine if providing burlap as enrichment can reduce the stress of weaning on piglets through reduced aggressive behaviours and fewer lesions. The second is to determine if there is a stage of life (pre- or post-weaning) when it would be most beneficial to introduce burlap to piglets. Piglet behaviour, lesion scores, mortality, and mass data were collected for three weeks pre-weaning and five weeks post-weaning. Four treatments were used to assess the timing of burlap provision: control (no burlap), post-weaning in the nursery room only (N), pre- and post-weaning in farrowing and nursery rooms (FN), and finally to the sow as well as to piglets pre- and post-weaning (SFN). Results of this experiment suggest that burlap enrichment positively impacts piglets through increased socialization and reduced aggressive behaviours. Results showed that burlap may have the greatest positive impact on piglets when provided in both farrowing and nursery rooms through increased piglet interaction with the burlap and fewer displacement behaviours. In summary, burlap is a promising low-cost enrichment option to improve the welfare of commercial piglets.
Open Access
Electrochemical Detection of Platinum-Based Chemoresistance and Correlation with MEK1 Activity in Living Cancer Cells
(2024-07-04) Daou, Roy; Whyhard, Steve (Biological Sciences); Doering, Jennifer (Biological Sciences); Lee, Jae-Hyeok (Biological Sciences); Kuss, Sabine
Drug resistance is responsible for most chemotherapy failures, making it an urgent issue in modern oncology. In ovarian cancer, resistance to platinum-based chemotherapeutics, such as carboplatin, is common. However, its underlying mechanisms remain poorly understood. A mitogen-activated protein kinase kinase, MEK1, may play a role in the development of this resistance mechanism. This project aims to understand this mechanism by using western blots to measure MEK1 activity in patient-obtained living ovarian cancer cells, comparing between carboplatin-susceptible and carboplatin-resistant cells. Moreover, early detection of chemoresistance can improve treatment outcomes. However, current detection methods are inefficient and time-consuming. To address this, the project also proposes an unconventional approach to identifying chemoresistance. This involves the use of scanning electrochemical microscopy for the rapid and accurate quantification of glutathione, a prominent antioxidant that may serve as a biomarker for platinum-based resistance mechanisms, in both cell lines. The findings suggest a correlation between lower MEK1 activity and increased glutathione levels in the resistant cells. This research may contribute to the development of an efficient and reliable method for detecting chemoresistance, with the potential of significantly improving cancer treatment outcomes.
Open Access
Energy Density of Capelin (Mallotus villosus) and Sand lance (Ammodytes americanus and Ammodytes dubius) during the summer in Coastal Newfoundland
(2024-07-05) Vonderbank, Kate; Stacey, Joy (Biological Sciences); Treberg, Jason (Biological Sciences); Davoren, Gail
Spawning capelin (Mallotus villosus) and non-spawning Atlantic sand lance (Ammodytes americanus, A. dubius) adults and juveniles are important forage fish species in coastal Newfoundland during July and August when high abundances of top predators rely on them as critical energy sources. To determine whether these prey types differ in their energy content, and interannual changes in quality, samples of each prey type were collected during July-August 2020 and 2023. Bomb calorimetry was used to measure whole-body dry energy density (kJ/dry g) and calculate wet energy density (kJ/wet g) and water content. Although sand lance are at the peak of their annual lipid cycle and capelin are at their minimum during the summer, adult female sand lance had lower dry energy density (mean of both years ± SE, 20.7 ± 0.11 kJ/dry g) than all capelin sex and maturity categories, and wet energy densities (4.4 ± 0.09 kJ/g) did not differ from capelin. Within capelin, wet and dry energy densities did not differ among gravid females, spent females and males, which contrasts previous findings from before the capelin population in Newfoundland collapsed. Within sand lance, juvenile dry energy density (20.8 ± 0.14 kJ/g) did not differ from adult females. Juvenile sand lance wet energy density was the only prey type that varied interannually, where energy density in 2020 was higher (5.3 ± 0.15 kJ/g), but this is thought to be because the samples were more dried out before collection. Overall, our findings indicate that although sand lance adults and juveniles are similar in wet energy densities to capelin, their lower wet mass per fish would result in a higher number of sand lance needed to reach a fixed energy content per meal. Other factors, including abundance and distribution of each species, also impact foraging costs and must be paired with energy densities to estimate prey type quality.
Open Access
Evaluating different double-stranded RNA structures for their ability to control pest flea beetles
(2023-04) Verhaeghe, Lauren; Belmonte, Mark (Biological Sciences); Whyard, Steve
Canola is an economically important Canadian crop that suffers significant annual losses by damage from feeding flea beetles (Phyllotreta cruciferae and P. striolata). Increasing incidences of resistance and concerns about off-target effects with current insecticides demands new methods of control. Recently, environmentally safer approaches to pest control have been investigated using RNA interference (RNAi), a sequence-specific gene silencing mechanism triggered by exogenous double-stranded RNA (dsRNA), to selectively induce the mortality of targeted species. This study examined three different dsRNA structures for their ability to kill P. striolata flea beetles and thereby reduce feeding damage on canola leaves. Long linear dsRNAs (212-214 bp), short hairpin RNAs (hpRNAs) (21-24 bp), and short paperclip RNAs (pcRNAs) (21-24 bp) targeting mRNAs of three essential genes, Ras opposite (Rop), Sec23, and Snf7 in P. striolata were investigated. P. striolata adults were fed dsRNA-treated canola leaf disks, and impacts on insect survivorship and leaf material consumption were recorded over an eight-day period. pcRNAs targeting Sec23 and Snf7, and long dsRNAs targeting Sec23 and Rop effectively killed flea beetles, resulting in the reduced consumption of treated canola leaf tissues. Consumption of both the Sec23-specific long dsRNA and pcRNAs caused similar levels of flea beetle mortality (68% and 76%, respectively), whereas only the Rop-specific long dsRNA and the Snf7 pcRNA were effective at killing the beetles (76% and 84%, respectively). hpRNAs proved the least effective across all gene targets, killing at most, between 40-52% of flea beetles, depending on the gene target, and in general, these values were not significantly different relative to the negative controls. While this study examined dsRNAs specific for only three target genes, it provides evidence that RNAi-based pesticides have the potential to control these economically important pests and that short pcRNAs can be as effective as conventional long linear dsRNAs.
Open Access
Exploring the role of ammonia transporters (AMTs) in the branchial tissue of the horseshoe crab, Limulus polyphemus
(2023-05) Whiting, Holly; Campbell, Kevin (Biological Sciences); Treberg, Jason (Biological Sciences); Weihrauch, Dirk
All organisms must manage ammonia as it is highly toxic and a product of many essential biochemical processes. One group of proteins that facilitates the movement of ammonia across cell membranes is the Ammonia Transport Protein family which are generally sorted into three groups—ammonia transporters (AMTs), Rhesus glycoproteins (Rh proteins), and methylamine permeases (MEPs)—expressed in plants, animals, and fungi, respectively. Recently, transcripts of AMTs have also been found in invertebrates, where experimental evidence suggest that they play a role in both ammonia excretion and ammonia sensing. The American horseshoe crab, Limulus polyphemus, expresses at least two AMT and two Rh proteins within the epithelia of their book gills which is the primary surface for ammonia excretion. Each gill lamellae have a ventral ammonia permeable side and a dorsal ammonia impermeable side. mRNA transcripts for both proteins LpAMT-1 and LpAMT-3 were found on the dorsal and ventral surfaces, bringing into question their function in direct ammonia excretion. In oocyte expression trials both AMTs failed to mediate the transport of radiolabeled methylamine, while transport was detected for both a coral and a human Rh protein. Direct evidence of ammonia transport by invertebrate AMTs has not been previously found and further research should be conducted into the function of these proteins in invertebrates.
Open Access
Improving mosquito (Aedes aegypti) sex-sorting methods for sterile insect technique using RNAi gene knockdowns
(2023-04) Rempel, Kadri
Doublesex (dsx) is an alternatively spliced mosquito (Aedes aegypti) gene that controls sex development by producing male (DSXM) or female (DSXF) transcription factors that regulate gene expression in a sex-specific manner. As both DSXF and DSXM bind the same DNA sequence, their ability to regulate differential gene expression is predicted to be modulated by other proteins that interact with DSX. A previously conducted protein-protein interaction study identified several proteins that bind to DSXF and their role in altering female development was explored in this study by knocking down their corresponding transcripts using RNA interference during the larval stages of development. Knockdowns of the genes nop-14, wdr-48, and rnmt was achieved by feeding mosquito larvae HT115 strain E. coli transformed with a pl4440 plasmid containing a dsRNA template specific to each of three target genes. The knockdowns were carried out at their normal rearing temperature, 28oC, and at 22oC to slow mosquito development. Knockdown of one of the genes, wdr-48, at either temperature, significantly increased the time to pupation of females compared to males. This delayed development of females could prove useful in the sex sorting of males and females during the pupal stage by providing a method to select only males for a sterile male insect (SIT) population control program for Ae aegypti. Of note, the 22oC growth conditions provided a larger difference in the pupation times between the sexes than the 28oC conditions did, and thus may provide even better sex-sorting for mosquito SIT.
Open Access
Individual timing consistency across purple martin (Progne subis) migrations
(2023-03) Bridges, Colin; Garroway, Colin (Biological Sciences); Davoren, Gail (Biological Sciences); Fraser, Kevin
Migration timing in long-distance migratory birds plays an essential role in individual survival and fitness. Migration schedules determine when individual birds depart and arrive seasonally between their overwintering and breeding sites. Bird migration timing may be largely driven by internal routines with some plasticity to environmental conditions, but individual timing across migrations has been little explored. To investigate the consistency of individual timing across migrations, I examined the individual order of migration timing in purple martins (Progne subis), a neotropical migratory songbird that travels between breeding sites throughout eastern North America and winter sites in Brazil. Migration timing data were collected for 295 different individual purple martins spanning over nine years by using light-level geolocators deployed during the breeding season at sites across the range and collected at the same sites the following year. I used a linear mixed-effect model (LMM) to examine the influence of the rank order of departure dates in one season on the rank order of four subsequent migration events while controlling for the effects of breeding latitude, sex, and age. Overall, I found that the individual rank order of migration timing in purple martins was conserved across migrations. Rank order timing was consistent between fall departure date from the breeding site and spring arrival dates in the following year (0.28  0.03, 95% CI 0.21-0.34), as well as the finer scale across fall migration departure and arrival dates (0.33  0.05, 95% CI 0.23-0.42), over the wintering period (0.39  0.04, 95% CI 0.30-0.48), and across spring migration (0.03  0.001, 95% CI 0.026-0.033). These results demonstrate that purple martin exhibit consistency in individual migration timing throughout the annual cycle. Migration distance also played a significant role, as the consistency of rank order timing lessened with distance traveled. Understanding how individual birds time migrations and if individuals are consistent between events can provide insight into how shifts in the environment with climate change could lead to a mismatch if migratory birds are unable to adapt. Future studies should examine if purple martins are able to adjust their migration timing and how long these changes persist in response to environmental alterations.
Open Access
Investigating the Relationship Between Insulin Processing and Senescence in β-cells
(2024-07-05) Préfontaine, Camille; Whyard, Steve (Biological Sciences); Campbell, Kevin (Biological Sciences); Thompson, Peter; Fry, Mark
Diabetes is a chronic metabolic disease characterized by an inability to regulate blood glucose levels. The two most common forms of diabetes, type 1, and type 2, result from a loss or defects in the pancreatic β-cells which make insulin. Recent experiments demonstrate that pancreatic β-cells can undergo a poorly understood stress response, known as senescence. Previous work on human pancreatic islets shows that insulin secretion is compromised due to senescent β-cells accumulating. However, the translation of INS (gene encoding preproinsulin) precursor mRNA does not appear to change in response to senescence, suggesting that decreased insulin content may occur at the post-translational or protein level rather than at the transcriptional level. Therefore, I hypothesised that senescence in human β-cells leads to a decrease in insulin because of decreased levels of insulin synthesis enzymes prohormone convertase 1/3 (PC1/3) and carboxypeptidase E (CPE), and increased levels of prohormone convertase 1 inhibitor (PCSK1N, hereafter referred to as ProSAAS). Both human pancreatic donor islets samples and a pure human β-cells model (EndoC-βH5), were treated with the DNA-damaging drug bleomycin to induce senescence. After bleomycin treatment, western blots were performed to evaluate the protein levels of PC1/3, prohormone convertase 2 (PC2), CPE and ProSAAS in senescent cells in comparison to vehicle controls. The western blot results showed that PC1/3 and CPE levels increased significantly in donor islets as a function of senescence. ProSAAS levels in senescence donor islets also increased significantly when compared to the control. However, the EndoC-βH5 exhibited an opposite phenotype to the donor islets, which is likely due to differences in cell maturity level and the impacts of microenvironments. These results suggest the donor islets are attempting to compensate for the decreased insulin content by up-regulating insulin synthesis enzyme production. The upregulation of ProSAAS could serve as a potential drug target to improve b-cell function in individuals with senescent β-cell accumulation during diabetes.
Open Access
Investigating the Roles of Homeobox Proteins and TEAD in Small Cell Lung Cancer
(2024-07-05) Ricarte, Bea; Pearson, Joel
Lung cancer remains a significant global health concern, responsible for a substantial number of cancer-related deaths annually. Small cell lung cancer (SCLC), one of its subtypes, is particularly aggressive and resistant to treatment, leading to a poor prognosis for patients. Unfortunately, treatment options for SCLC remain limited and have not been advanced for decades. This highlights the urgent need for a deeper understanding of the molecular mechanisms underlying the pathogenesis of SCLC in order to identify novel therapeutic strategies for this disease. DNA-bind proteins, TEADs, play a crucial role in promoting SCLC survival. TEADs are best recognized for their role in interacting with transcriptional activators, YAP and TAZ, however, it was found that the function of TEADs in SCLC is completely independent of YAP and TAZ. Beyond this however, the mechanisms underlying the critical function of TEAD in SCLC is unknown. Preliminary data gathered by the Pearson lab identified the presence of homeobox proteins PROX1, NKX2-1 and NKX2-2 with the TEAD complex in SCLC, prompting the hypothesis that TEAD interacts with these proteins to silence TEAD target genes in SCLC, promoting the cancerous state. Using co-immunoprecipiation, the association of TEAD with PROX1 and NKX2-1 were confirmed. Additionally, CRISPR interference was used to knockdown PROX1, NKX2-1 and NKX2-2 in SCLC cells, to assess their role in TEAD-mediated gene regulation. This resulted in an increase in controlled cell regulation and differentiation genes, and a decrease in SCLC biomarkers, consistent with the hypothesis. However, contrasting the hypothesis, protein knockdowns showed a decrease of cell adhesion genes. Nevertheless, these findings bring light to a novel pathway in SCLC pathogenesis. Understanding the exact mechanisms behind these homeobox proteins and their interaction with TEADs could lead to the development of more effective treatment for SCLC.
Open Access
IRE1 Activation in Spinal Cord Development and Repair in the Zebrafish Model
(2024-07-05) Talabis, Kayla; Jeffries, Kenneth (Biological Sciences); Stacey, Joy (Biological Sciences); Whyard, Steve (Biological Sciences); Lindsey, Benjamin
The Unfolded Protein Response (UPR) is a cellular pathway that functions in the maintenance of proteostasis in response to endoplasmic reticulum (ER) stress. Recent studies implicate the IRE1 branch of the UPR in the development of the central nervous system (CNS) and in response to spinal cord injury (SCI). To date, studies have focused mainly on mammalian models and thus we know little about the role of the UPR in the CNS of other vertebrates. In this study, we take advantage of the many attributes of the zebrafish model, including its capacity for neurorepair, to investigate the activation of IRE1 during spinal cord development and following SCI. Using the Tg(xbp1s:eGFP) transgenic reporter fish that expresses GFP upon IRE1 activation, we show that IRE1 is strongly upregulated in early larvae compared to juveniles and adults. High levels of IRE1 expression are displayed at 4-days post fertilization (dpf) and drop off into adulthood. Interestingly, when exposed to the ER stress inducing drug Dithiothreitol (DTT), larvae at 4-dpf also show slight elevated levels of IRE1 activation compared to later stages of development, suggesting IRE1 is less inducible with age. We next established a larval SCI model to ask whether IRE1 expression was upregulated after SCI. We demonstrate that, in contrast to mammalian models, spinal cord IRE1 activity remains the same or slightly decreases following SCI.
Open Access
Lipids in Anadromous Northern Dolly Varden (Salvelinus malma malma)
(2023-03) Kulchycki, Lisa; Loseto, Lisa; Davoren, Gail
Anadromous Arctic fish species have adapted to a particular environment by evolving unique lipid cycling strategies such as storing large amounts of lipid during times of high productivity in order to survive long migrations, spawning events, and seasonal variation in food availability. Research on lipid content and storage location in the body is very limited, especially regarding the northern Dolly Varden, a fish species important culturally and for sustenance to the Indigenous Peoples in the western Canadian Arctic that is listed as ‘Special Concern’ under Species at Risk legislation. Lipid content in anadromous Dolly Varden obtained from two marine (coastal) (summer) and two freshwater (fall) locations were examined and compared to test for differences in percent lipid between locations/seasons. Percent lipid was compared between the muscle and homogenized whole-body of individuals caught in freshwater. Muscle lipid content was significantly different between freshwater locations and one of the marine locations (~34% higher from the marine location). One marine location contained fish with unexpectedly high muscle lipid percent. A weak/moderate linear relationship was found between lipid percent in the muscle tissue and whole-body tissue of the same individuals (r2= 0.2013 when sex was an added variable; r2= 0.4204 when reproductive status was an added variable), and reproductive status influenced this relationship. Sex of the individual did not affect lipid content in the muscle nor on the relationship between percent lipids in muscle and whole-body. Changing environmental factors due to climate change such as the timing of the ice melt and phytoplankton blooms can affect energy exchange through the food web, and thus research on the nature of fluctuating energy and lipid levels is needed to aid in conservation efforts of Arctic species.
Open Access
Mixed-Grass Prairie Field Restoration: How long does it really take?
(2024-07-04) Farrant, Daryn; Zelmer, Carla (Biological Sciences); Fraser, Kevin (Biological Sciences); Koper, Nicola; Markham, John
This thesis explores the success of mixed-grass prairie field restoration efforts in Grassland National Park, SK (GNP) by analyzing the progress of several fields over time; Laouenan 2001, Belzas 2003 and Gergovia 2005, relative to GNP’s target endpoints. The surrounding vegetation is dominated by native grasses. In addition, I ran a space for time analysis on the Gergovia fields, where measured data from 2021 for fields of varying seeding, years was substituted for time. This allowed me to use data collected from the newer monitoring protocol to track changes in vegetation over time. Cover estimates of bare ground, litter, native herbaceous were tested against target endpoints chosen by GNP to reflect that of native prairie, extrapolated from Thorpe (2007), in order to determine if a field is considered restored. Based on the findings of this study we can conclude that GNP’s fields that met targets for bare ground took an average of 10 years to match that of native prairie. In all GNP’s fields the bare ground target took the longest to be met, with one field failing to meet the target 13 years after seeding. Furthermore, at GNP, native grasses took an average of 5 years to establish and reach the target endpoint. Litter in all fields were found to exceed that of Native prairie, indicating a need for a prescribed burn or other management strategies. The endpoint target not met (exceeding the target) 10 years post-seeding was non-native species which could be reduced using a prescribed burn. This study underscores the importance of comprehensive monitoring protocols, field initiation and seed mix documentation for evaluating restoration success accurately. Overall, the findings affirm the effectiveness of GNP's restoration efforts and emphasize the need for further research into species composition and diversity to fully meet the SER (2004) criteria of a restoration project, which includes the reparation of ecosystem processes, productivity and services, and the re-establishment of the pre-existing biotic integrity in terms of species composition and community structure (SER 2004).
Open Access
Plant species-specific Effects on Boreal Soil Fertility in Mature and Fire-Disturbed Forest
(2024-07-04) Klapprat, Emily; Worley, Anne (Biological Sciences); Fraser, Kevin (Biological Sciences); Markham, John
Soil fertility is the ability for soil to meet the requirements for plant growth. The soil fertility is influenced by both fire disturbance and plant species. Competitive species contribute higher quality leaf litter than stress-tolerant species in the boreal forest which influences aspects of soil fertility. The effect that plants with different life history strategies have on soil fertility has not been studied in the context of high-severity fire. Soil fertility variables including organic layer depth, soil temperature, soil respiration rate, pH, inorganic nitrogen content, percent soil organic matter, and percent water retention were compared between soil samples from replicate plots in the boreal forest near Churchill Manitoba, and soil samples from replicate plots in a fire-disturbed site in the boreal forest. Additionally, soil fertility variables were compared between soils sampled from competitive species (Salix candida) and stress-tolerant species (Empetrum nigrum and Vaccinium uliginosum) growing in the two sites. Statistical differences in soil variables were found between soil samples from the boreal forest and soil samples from a fire-disturbed site. High-severity fire reduces the organic layer depth and decreases the pH, soil respiration rate, and available nutrients. Inorganic nitrogen content and relative growth rate of sea lyme grass grown in soil samples were statistically different between the competitive plant Salix candida and the stress-tolerant plants. Salix candida influences soil fertility by increasing the inorganic nitrogen content and fostering soils that increase the relative growth rate of sea lyme grass. As the frequency, intensity, and severity of fires in the boreal forest are increasing due to climate change, it is important to understand how species impact soil fertility.

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