Biology - Master's Theses

Permanent URI for this collectionhttps://laurentian.scholaris.ca/handle/10219/2005

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Investigating the role of hydrogen sulfide in the regulation of glucagon-like peptide-2 secretion and gut physiology
(2023-08-29) Hammond, Joel
Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter which regulates a variety of physiological processes including hormone regulation. In individuals with Crohn’s disease or colitis, H2S is elevated. Whether H2S plays a role in gut disease development or protection is not clear. Glucagon-Like Peptide-2 (GLP-2) is a gut health-promoting peptide hormone produced in the enteroendocrine L-cells (EECs) located primarily in the distal gastrointestinal (GI) tract. In the gut, GLP-2 increases cell proliferation, enhances barrier function, and decreases inflammation. In this study, it is hypothesized that local H2S produced in the distal GI tract and in EECs can regulate GLP-2 secretion and downstream gut physiology. GLP-2 secretion and gut physiology was examined in mice lacking the H2S producing enzyme cystathionine gamma-lyase (CSE). Additionally, H2S production and GLP-2 secretion was examined from mouse enteroendocrine L-cells (GLUTag). CSE knockout (KO) mice had significantly reduced intestinal H2S production and claudin-7 expression. In cells, H2S was also produced directly from EECs which could be partially blocked by CSE inhibitors. When EECs were treated with H2S donors (NaHS and GYY 4137), the effect on GLP-2 secretion was variable with a slight suppression with high dose NaHS and no effect with GYY 4137. Finally, when cells were treated with CSE inhibitor, GLP-2 secretion was significantly reduced. Our work indicates that the EEC L-cell can produce the gasotransmitter H2S. Adding additional H2S has a variable effect while inhibiting endogenous production suppresses GLP-2 secretion. These findings suggest that GLP- 2 may play a role in the interplay between H2S and gastric health, which could provide support for the potential use of H2S drugs in the treatment of GI diseases.
Assessing fish biodiversity in northeastern Ontario drainage basins: methodological and landscape effects
(2024-09-05) Fields, Emily N.
Inland waters and their fish communities constitute a valuable resource for Canada. Long-term monitoring of fish communities in Ontario supports both fisheries management and biodiversity assessment. Traditionally, fish monitoring programs have relied on gill net surveys of sportfish-dominated larger lakes (≥ 50 ha) which may not adequately sample some aquatic habitats or fish species, and thus underestimate biodiversity. The issue is important in northeastern Ontario, where historical acidification led to significant loss of fish resources. A more thorough and robust assessment of the recovery of fish communities in this region may require a multi-gear and multi-habitat approach. My research objectives were to examine the efficiency of current gill net community surveys as a fish biodiversity assessment tool, and to explore patterns in fish biodiversity in relation to landscape characteristics at multiple scales in the historic acid deposition zone of northeastern Ontario. My first chapter compares fish species richness estimates from Broad-scale Monitoring (BsM) surveys with those derived from alternate protocols, and a multi-gear approach (BsM surveys plus alternate sampling protocols) designed to sample habitats and species that are believed to be poorly sampled by gill nets. Sampling was carried out on 30 lakes in the historical acid-damaged zone of northeastern Ontario. Species detected increased asymptotically with sampling effort. Maximum species detection (Smax) differed greatly among gear types, but no individual gear was able to effectively sample the full fish community. In contrast, the effort required to achieve 80% of Smax was quite similar among individual gears. Integrating all individual gears (Combo protocol) detected significantly more species than the BsM protocol at higher sampling effort (≥18 efforts). BsM surveys detected 73.8 ± 15.4% (mean ± 1 SD) of all fish species detected in my study lakes, often missing species that use extreme nearshore and tributary habitats. BsM detection efficiency was negatively related to abundance of smallmouth bass. My second chapter examines patterns in fish biodiversity within and among six drainage basins covering a gradient of historical acidification damage (three acid- recovering, three reference) in northeastern Ontario. Fish biodiversity was higher in reference drainage basins than acid-recovering drainage basins; this trend was most evident when biodiversity was measured as species richness and Shannon’s diversity, and less evident when measured as Simpson’s diversity. Differences in fish biodiversity between reference and acid-recovering drainage basins were also more pronounced when analyzed with BsM survey data than with nearshore and tributary Gee trap data. Biodiversity estimates tended to be higher in large sentinel lakes located at lower elevations in the drainage basin. Fish biodiversity in lakes was most strongly linked to contemporary pH, but latitude, relative elevation and lake size were also significant factors in some analyses. My study provides a critical evaluation of the role of the BsM program in fish biodiversity assessment, provides an updated and more comprehensive approach to examining status and recovery of fish communities, and will inform targeted conservation efforts in north temperate landscapes.
Effect of copper and nickel on soil microbial activities, abundance, and diversity using the Illumina NovaSeq Platform
(2024-09-13) Suszter, Michael
The objectives of the study were to determine the effects of nickel and copper on soil enzymatic activity, and microbial populations in an environmentally controlled setting. Soil samples were incubated for 100 days, then enzyme assayed, and metagenomically profiled using Illumina amplicon sequencing. No differences were found in enzyme activity in samples treated with copper and nickel sulfates compared to the water control. Surprisingly, potassium induced a significant increase in glycine aminopeptidase (GA). The abundance of the top five bacterial and fungal genera relative remained mostly consistent across treatment groups, with only minor changes in rank order. Copper decreased significantly the abundance of the top five most predominant genera, the levels of amplicon sequence variants (ASV) and Shannon Diversity Index values for both bacteria and fungi compared to controls. The decrease induced by nickel was not strong enough to achieve statistical significance. Future studies should focus on assessing the effect of different concentrations, of copper, and nickel, on soil microbe populations, in lab, to determine the threshold concentrations at which copper and nickel has an effect.
Quantification of turtle capture efficiency and the impact of development on plant communities within community-selected priority areas in Eastern Georgian Bay
(2024-06-13) Carroll, Brooke
A worldwide biodiversity crisis coupled with rapid and irrevocable habitat destruction have caused many conservation groups and local communities to identify research and conservation priorities. In the Eastern Georgian Bay region of Ontario, linear developments such as roadways and transmission lines destroy and fragment pristine upland and wetland habitats, and are likely to have measurable effects on local ecology. Local First Nations, not-for-profits, and municipalities identified several habitats adjacent to linear developments as conservation priority areas, and turtle and plant communities affected by those linear developments as research priorities. The objective of my study was to provide communities with site-specific ecological data to inform their decision-making as they navigate land-use changes within local habitats. More specifically, I provided local partners with (i) turtle community census data, which I also used to assess the efficiency of different survey methods for turtles, and (ii) plant community census data, which I also used to assess how linear developments are affecting their overall health and composition. During my turtle community research, I located 772 turtles and found that survey efficiency (number of turtles caught per unit sampling effort) increased with warming temperatures in early spring, and that using multiple sampling methods may help decrease taxonomic and size biases. During my plant community research, I assessed the distribution of 10 tree species and 63 understory species across 150 upland forest plots at Magnetawan First Nation, which revealed that linear developments are affecting functional and taxonomic diversity of plant communities and facilitating establishment of introduced species. Overall, my study highlights the value in local partnerships, provides survey efficiency recommendations for freshwater turtle populations, and provides evidence that linear developments are or will negatively affect turtle and plant communities in the Eastern Georgian Bay region.
Investigating the impact of perinatal EMF exposure and nitric oxide modulation on rat brain development: a histological analysis of neuronal alterations and GFAP expression
(2024-06-13) Sissons, Stephanie
The environment in which we develop can have profound but subtle impacts on a multitude of biological systems. Small changes in this environment during prenatal development, such as the presence of an electromagnetic field (EMF) have been shown previously to have the ability to alter the neurobiology and behaviour of humans and animals. The present study builds on current knowledge of environmental influences by investigating the impact of nitric oxide (NO) modulation and EMF exposure on neurodevelopment. During a previous study rats were exposed perinatally to either water, 1g/L of L-arginine (LA), or 0.5g/L of N-methylarginine (NMA) and a 7Hz square wave EMF at three separate intensities (0nT, ≤50nT, and 500nT) starting ~3 days prior to birth and completing 14 days after. They were then allowed to develop until adulthood and their brains were harvested (Mean age=568.17 days, SD=162.73). While the prior study focused primarily on behaviour, the present study examined possible changes to the neurobiology by looking at alterations in neuron counts and glial fibrillary acid protein (GFAP) expression. Results of which, highlight significant changes in multiple brain areas including the amygdala, hippocampus, cortices, and hypothalamus, resulting from NO modulation and EMF exposure. Particularly, exposure to EMF resulted in a significant increase in neurons within the right secondary somatosensory cortex along with a significant increase in the average length of branches on GFAP-expressing cells in the right ventromedial hypothalamus. Additionally, sex-specific interactions with the EMF exposures were observed in the hippocampus where females exposed to the EMF had a significant increase in the number of neurons within the left CA3 compared to males. However, the EMF exposure elevated the number of branches on GFAP-expressing cells in the left CA2 of male rats. These results point to an intricate interaction-based relationship between sex, hemisphere, NO modulation and EMF exposure during developmental periods.
Examining the impact of physiologically patterned EMF and LED on the growth of malignant cells: an analysis of the Novel Ca2+ EMF
(2024-06-14) Rain, Benjamin
It has been proposed that all living biological systems are capable of emitting or detecting electromagnetic energies as a way of communicating within and between individual units. Should this statement be valid, it opens the door to the possibility of manipulation through artificial application of the appropriately patterned electromagnetic energy. Common forms of electromagnetic energies that are relevant to biological systems include electromagnetic fields and light. Here we explore the possibility for physiologically patterned, frequency modulated electromagnetic fields (EMF) and light-emitting diodes (LED) to influence the growth and viability of malignant (B16-BL6) and non-malignant (HEK 293-T) cell lines. When applied for a single 40- minute exposure, the novel, physiologically patterned Ca2+ EMF reduced the growth of malignant cells 50.3%. Importantly, this same procedure had no effect on non-malignant cells. When applied as an LED, the effects of the Ca2+ pattern were entirely dependent on the wavelength of light. While red (645 nm) LED demonstrated a significant reduction in B16 viable cell counts consistent with the anti-cancer properties of the EMF, blue (470 nm) LED promoted a significant increase in viable cell counts. Finally, we sought to determine the most optimal application parameters of the Ca2+ EMF by adjusting its temporal characteristics. Reducing the point durations from 10 ms to 3 ms further decreased the viability of B16 cells therefore suggesting 3 ms as the optimal time increment for anti-cancer effects. Overall, these results show the ability for specifically patterned EMF and LED to influence the growth of malignant tissues. As such, our findings pose the potential for the Ca2+ EMF to act as a specific, non-invasive, cost- effective therapeutic to be used in the treatment of cancers.
Impacts of wildfire and windfarm construction and operation on herpetofauna community ecology
(2024-04-30) Maloney, Aidan J.
Climate change and its associated impacts threaten global biodiversity. Increases in wind energy harvesting to reduce carbon emissions, coupled with increases in wildfire frequency and severity, may pose risks to wildlife. I investigated potential impacts of windfarm operations and wildfire on herpetofauna biodiversity, anuran calling behaviour, and snake health, in an area where both impacts occurred simultaneously. I measured biodiversity metrics using squamate cover surveys and anuran acoustic monitoring across 4 replicated site treatments: Control, Wind, Burn, and WindBurn (double impact). Anuran diversity, evenness, richness, and relative abundances were lowest in Wind sites, whereas metrics in Burn sites did not differ from those in Control sites. Squamate total abundance was lowest in WindBurn sites, but other investigated metrics did not differ between impacted and non-impacted sites. More research using a Before- After-Control-Impact (BACI) study design is needed to understand the acute and chronic impacts of these disturbances on at-risk wildlife species.
Examining the impact of applied LEDs and EMFs on biological systems: analysis of photon emission characteristics and cell viability
(2024-03-15) Ravindran, Rahul
All living biological systems naturally emit light, a phenomenon commonly referred to as biophoton emission. This emitted light serves as a valuable source of information about the inherent properties of the biological system. Notably, alterations in biophoton emission, resulting from external factors such as electromagnetic fields or exposure to light-emitting diodes, are readily observable and well-documented. Alterations in photon emission induced by external applications were initially measured in both malignant (B16-Bl6) and non-malignant (HEK-293) cell lines. A notable disparity in spectral power emerged between the two groups, specifically at the emission frequency of 23.4Hz. Subsequent research focused on the B16BL6, introducing an electromagnetic field (EMF) application for 15 minutes. The application of a time-varying, frequency-modulated EMF demonstrated a reduction of viable B16-BL6 cells, with significant effects noted for the LED application. Notably, biophoton emission at the 13Hz frequency exhibited increased spectral power following LED exposure, and this frequency displayed a strong correlation with the number of non-viable cells. Expanding the investigation to a different cell line, MCF7 breast cancer cells, measurements were taken on both wild-type and doxorubicin-resistant MCF7 cells exposed to either a 40Hz or Thomas EMF application. A substantial reduction in viable cells was evident after exposure to both 40Hz and Thomas EMF applications. These findings suggest that external applications not only influence the intensity and frequency of biophoton emission but changes in both may serve as indicators of future cell viability. Overall, these results highlight the potential of external applications, such as EMFs or LEDs, as non-invasive therapeutic tools in the combat against cancer, shedding light on their influence on biophoton emission and their potential role in predicting and impacting cell viability.
Examining the stress response in anhydrobiotic yeast (Saccharomyces cerevisiae)
(2024-04-02) Ratnayake Mudiyanselage, Rasathma
Yeast (Saccharomyces cerevisiae) is a unique model system for biological research due to the fact that it can be maintained in a dry desiccated state of anhydrobiosis for lengthy periods of time without the need for water or nutrients. However, there is very limited understanding of how anhydrobiosis impacts the natural stress response. The objective of this thesis was to study the thermal stress response in yeast pre- and post-desiccation. It was hypothesized that desiccation induces a stress response in yeast which makes them resistant to a thermal stress, and that as rehydrated yeast start to enter exponential growth, the stress response will be down regulated resulting in return to normal thermal sensitivity. To study this, two different strains of yeast were used: a wild type strain (YBS21-A) and a rad51 mutant strain (YBS29-1) that is defective in homologous recombinational DNA repair. Yeast samples were exposed to heat shocks pre- desiccation, as well at various timepoints post-rehydration. Survival was quantified at each timepoint following a heat challenge to identify shifts in thermal-sensitivity. In addition, transcriptional changes were quantified using RT-qPCR to identify which genes might be regulating the response. Immediately post rehydration, thermal survival to a potentially lethal heat challenge of 52oC for 10 minutes was high. Thermal tolerance then started to gradually decrease and survival decreased to up to three orders of magnitude by the 12 hour timepoint. Following this, heat tolerance began to increase back to almost 100% survival by 18 and 24 hours post rehydration. The trends in growth rate were opposite to that of survival. When cell growth rates were at their highest (exponential phase), thermal tolerance was low, whereas when growth rates were low (lag phase and stationary phase), thermal tolerance was high. The expression levels of multiple heat shock proteins were found to correlate with thermal survival, including hsp104, hsp78, hsp42 and hsp12, suggesting that they may be regulating thermal sensitivity. Interestingly, there was no difference in survival between the wild type and rad51 strains, suggesting that heat shock induced cell death is independent of DNA double strand break repair. Overall, this foundational knowledge of the stress response during anhydrobiosis and how it impacts thermal sensitivity is important for the use of desiccated yeast as a model organism for long term low maintenance biological research.
Assessment of the recovery of littoral zone food-webs in Lake Charr Lakes in Killarney Provincial Park affected by acidification and contemporary stressors
(2023-12-12) Moskal, Haley
Killarney Provincial Park is a site of significant environmental damage from acidic deposition resulting in the extreme loss of biodiversity. As many lakes in Killarney Park acidified to pH< 6, many populations of fish and sensitive species were lost from Killarney’s lakes and streams. In recent decades, effective legislation, and massive emission reductions programs have resulted in substantial chemical recovery, however biological recovery has lagged considerably behind. The objective of my study was to assess the recovery of littoral zone food- webs in Killarney’s acid damaged lake charr (Salvelinus namaycush) lakes by resampling 20 lakes previously studied 25-years earlier, with a focus on assessing change in water quality, and key prey and indicator species (crayfish, mayflies, amphipods, littoral fish). Dramatic water quality shifts have occurred in these lakes including increases in pH and DOC and decreases in SO4 2-, Ca2+ and metals and increase in surface water temperatures. The substantial rise in DOC may represent a significant increase in nutrient conditions, but more importantly appears to have affected the thermal structure and cold-water habitat for charr in some ultra-clear lakes. In contrast to the physicochemical changes in the lakes, particularly the substantial pH rise to above toxic levels, the biotic changes were not all as positive. There is evidence that emerging contemporary stressors, including declining Ca levels and shifts in littoral fish communities to centrarchid-dominated may be inhibiting recovery potential in the littoral zones. My results demonstrate the importance of the interactions between historical and contemporary stressors, and that contemporary stressors may now be controlling variables in determining littoral food web recovery. Overall, my study provides evidence that many of Killarney Park’s historically acid-damaged lakes are no longer limited by acidic conditions but contemporary stressors, such as the arrival of warm water centrarchids (e.g. smallmouth bass) have emerged as key factors shaping littoral zone recovery. In particular, the increase in concentration of dissolved organic carbon may be a potential driver of littoral zone recovery, providing food source additions to the nearshore environment and increasing the productivity capacity of food webs.
Assessments of genetic and reproductive health in Canada’s endangered Oregon Spotted Frog (Rana pretiosa)
(2023-08-04) Hunter, Briar
Zoological institutions are increasingly relied upon for ex situ management of species at risk, with conservation breeding and reintroduction programs providing both assurance against extinction and a reliable source of offspring to reinforce wild population sizes. Ex situ efforts face many challenges, however. One often overlooked challenge is balancing genetic priorities, like retaining genetic diversity and reducing inbreeding, with reproductive priorities, like mate compatibility and reliable breeding, both of which are required for a successful program. Like many amphibians, the Oregon Spotted Frog (Rana pretiosa) is highly threatened in its native habitat and ongoing conservation breeding and reintroduction programs are experiencing limited success; the genetic sustainability of these populations remains unassessed. In this study, I evaluated the genetic health of both zoo and wild populations of R. pretiosa in Canada and investigated some potential causes of the ongoing ex situ reproductive failures associated with egg binding. I found that zoos have maintained stable genetic metrics relative to their wild sources, but ongoing collections from wild populations should be reassessed due to low genetic diversity available therein. No clear causes of egg binding were elucidated but I found older female frogs (> 3 years old) who became egg bound generally had a higher body mass than conspecifics, while body mass did not differ in females becoming egg bound in their first breeding season (2-3 years old). This suggests frogs should be monitored for egg binding and changes in body condition differently depending on their age. Overall, there were no significant differences in genetic or reproductive health across the three zoo conservation breeding populations, but scaled mass index was significantly lower in the zoo with larger holding tanks and less genetic management: a reminder of the importance of husbandry and environment in conservation breeding program outcomes. The costs and benefits of strict genetic management vs. a more communal breeding approach should be carefully considered in light of these results. Along with more cohesion, communication is required between all involved institutions to have an effective impact on the conservation of Oregon Spotted Frogs in Canada, the recommendations discussed here have applicability to amphibian ex situ programs worldwide.
Determining the relative impacts of natural and anthropogenic contamination in the Tambo River Basin, Peru
(2023-06-20) Girard, Lianne Monique
Peruvian Andean Watersheds are under pressure. Mining, agriculture, urbanization, and natural stressors such as climate chance and geothermal and volcanic activity are causing water quality to deteriorate. Although rapidly declining, little attention has been given to understanding the current state of these watersheds and literature is often limited to grey literature such as academic theses and governmental reports which are difficult to access. Without baseline information on water quality, it can be challenging to properly identify sources of contamination and effectively manage these aquatic ecosystems. In this context, the water quality of the Tambo River Basin was assessed. Located in Southern Peru, the Tambo River Basin is subject to pressures from a variety of stressors such as a metal mine at its headwaters, geothermal and volcanic activity, agriculture, and urbanization. Water chemistry samples, physicochemical water quality measurements and benthic macroinvertebrates were collected from 15 sites across the basin, representing the different sources of contamination from source to mouth. Signs of contamination were evident at sites impacted by the mines, where acidic pH was recorded along with high metal concentrations exceeding Peruvian Water Quality standards for both drinking water and the aquatic environment. Sites along geothermal sources of contamination showed high concentrations of arsenic exceeding Peruvian Water Quality standards for both drinking water and the aquatic environment. At the most downstream and urbanized sites, high concentrations of lead were recorded. To our knowledge this is the first study of benthic macroinvertebrates in the region, thus it provides baseline information on the benthic macroinvertebrate communities of the Tambo River Basin. Changes in abundance, taxa richness and EPT% were compared at sites with different sources of contamination. More pollution-tolerant taxa dominated the contaminated sites and pollution-sensitive taxa were present at sites that had better water quality. Overall, this study provided baseline information on the water quality of the Tambo River Basin and helped to identify sources of contamination entering the basin contributing to pressures on the water quality and the aquatic environment. The use of benthic macroinvertebrates helped supplement physicochemical and chemistry water quality data which provides information on the conservation and management of the aquatic environment. However, given the complexity of the altitudinal gradient of this basin, this type of study should be repeated during both the dry and rainy seasons to further build upon this database. Efforts should also be directed towards preserving the ecological integrity of high altitudinal wetlands (bofedales) as they possess contaminant filtering capacity.
The role of animal personality in the pace-of-life of coexisting rodents
(2023-08-22) Hughes, Bryan
The pace-of-life syndrome hypothesis (POLS) predicts that life-history, behaviour, and physiology correlate along a fast to slow continuum. Relationships between POLS domains evolve in response to natural selection and energetic trade-offs at different phylogenetic levels. Access to resources is dependent on movement within a home-range, and differences in movement strategies should arise to accommodate competition among sympatric species and between conspecifics. I examined behaviours relating to home- range movement among sympatric rodents and between sexes. I tested two hypotheses: (1) sympatric rodents will express differences in movement behaviours to accommodate resource competition; and (2) differences in behaviour and physiology will arise between sexes because of differences in reproductive costs. I found differences in behaviour among species, and a uniform expression of traits relating to movement within a home- range between sexes. My results help to understand differences in animal personality, movement patterns and sex-specific strategies in rodents.
Weaving Indigenous knowledge and western science to investigate the impacts of railways on wildlife
(2022-09-29) Vincent, Kyle D.
Railways have been documented to cause mortalities for many different species, but overall, the ecological impacts of railways are under-researched and poorly understood. To date, railway ecology research has mainly focused on large mammals, but to develop effective railway mitigation, it is important to understand risks for underrepresented taxa. My aim was to use a Two-Eyed Seeing approach that weaved Indigenous knowledge and western science to improve understanding of railway ecology for understudied species and to help guide future mitigation efforts. In partnership with two First Nations, community members were invited to share Indigenous knowledge (IK) of wildlife-railway interactions to inform study design, then I conducted weekly visual surveys over three field seasons along two 3.6 km sections of railway in Eastern Georgian Bay, Ontario, recording the locations of live and dead wildlife. I recorded 462 observations of individuals from 42 different species, of which 76% were found dead, and 24% were encountered alive, findings complemented by shared IK. Reptiles and amphibians were the most severely impacted taxa, accounting for 87% of observed mortalities. Additionally, I identified hotspots of turtle and anuran interactions, and found that the locations of interactions were related to adjacent habitat use and railway features. Ultimately, this study highlights the value of collaborative research that uses complementary knowledge systems, indicates that reptiles and amphibians may be particularly susceptible to railway mortality, and identifies areas to target future mitigation both locally and in relation to broad scale landscape features for turtles and anurans.
Transcriptome analysis reveals changes in whole gene expression, biological processes and molecular functions induced by nickel and copper ions in Jack Pine (Pinus banksiana)
(2023-05-15) Moy, Alistar
Understanding the genetic response of plants to nickel and copper stress is a necessary step to improving the utility of plants for environmental remediation and restoration. The objectives of this study were to: 1) Characterize the transcriptome of Jack Pine (Pinus banksiana) and 2) Analyze the gene expression profiles of genotypes exposed to nickel and copper ion toxicity. Pinus banksiana seedlings were treated with 1,600 mg/kg of nickel sulfate or 1,300 mg of copper sulfate and screened in a growth chamber. Overall, 25,552 transcripts were assigned gene ontology. Nickel resistant and water control genotypes were compared based on the gene expression of various gene ontology categories. The response to stress and to chemical terms comprised the highest proportion of upregulated gene expression whereas the biosynthetic process and carbohydrate metabolic process terms had the highest proportion of downregulated gene expression. The majority of upregulated genes were expressed in the extracellular region and the nucleus whereas most downregulated genes were expressed in the plasma membrane and extracellular region. For copper, there were 6,213 upregulated genes and 29038 downregulated genes expressed in the copper resistant genotype compared to the susceptible genotype at a high stringency. Among the top upregulated genes, the response to stress, the biosynthetic process and the response to chemical stimuli terms represented the highest proportion of gene expression for the biological processes. For the molecular function category, the majority of expressed genes were associated with nucleotide binding followed by transporter activity and kinase activity. For the cellular component category, the majority of upregulated genes were located in the plasma membrane. Half of the total downregulated genes were associated with the extracellular region. Two candidate genes associated with copper resistance were identified including genes encoding for heavy metal-associated isoprenylated plant proteins (AtHIP20 and AtHIP26) and a gene encoding the pleiotropic drug resistance protein 1 (NtPDR1). This study represents the first report of transcriptomic response of a conifer species to nickel and copper ions.
Enhancing the immune responses using the synergistic effects of TLR4 and NOD2 agonists for multifaceted vaccine development
(2022-10-27) Praavaa, Jovial Akashh
Effective and defined adjuvanted vaccines can provide enhanced immunity to intra-cellular pathogens, which disproportionately affect certain immunocompromised individuals. Also, the importance of T-cell mediated immunity is vital in reducing the severity of intra-cellular infections. Strategies to increase vaccine immunogenicity include the addition of innovative adjuvants, which can help to achieve robust and persistent immune responses against infectious diseases. Despite the indispensable importance of adjuvants, only an extremely limited number of adjuvants have been included in licensed vaccines. That is why a search for more effective adjuvants has become one of the primary concerns in medical research. Simultaneous stimulation of germ-line encoded pattern-recognition receptors of the innate immune system, particularly Toll-like receptors (TLRs) and Nucleotide oligomerization domain (NOD)-like receptors (NLRs) can augment the cellular immune response. With this in mind, I hypothesized that adjuvants that activate TLR of NLRs would enhance vaccine response. To study this we developed a bioassay model of cytokine secretion using murine immortalized and primary antigen presenting cells(APCs), which were stimulated with diethanolamine-based lipid A (A1), a synthetic lipid A TLR4 agonist, and muramyl dipeptide (MDP),a NOD2 agonist in the presence or absence of the currently available high-dose influenza vaccine, Fluzone®. We evaluated the immune response by measuring cytokine secretion, protein cell signaling, and cell surface markers. We showed that A1 in combination with MDP was able to induce enhanced early innate immune responses synergistically by increasing ERK1/2 phosphorylation and increasing proinflammatory cytokine secretion. Next, we assessed the A1- MDP adjuvanted-Fluzone vaccine formulation against drifted influenza virus A/H3N2 variants in an antigen challenge protocol on human peripheral blood mononuclear cells (PBMCs). There were significant enhanced releases of IFNγ, IL-6, and IL-1β with no significant changes in IL-10 secretion and increased expression of CD8+ T (cytolytic T cell) cell surface markers, which suggested a polarized antigen-specific Th1 immune response. In summary, our combined adjuvant approach will ameliorate current vaccines especially for intracellular infections.
A nutrient analysis of traditional Anishinaabe recipes and the role of folic acid in the regulation of anti-diabetic GLP-1
(2022-07-13) Roque, Connor Francis
Type 2 diabetes (T2D) is a metabolic disease that results from insulin resistance or limited insulin production. The prevalence of T2D disproportionally burdens Indigenous people in Canada. Interventions including dietary change can improve diabetes outcomes; however, many aspects of Indigenous food knowledge and their role in metabolic health have not been investigated. This research sought to examine traditional Anishinaabe recipes and the metabolic effects of abundant nutrients within them. Several beneficial nutrients were identified, including folate. As folate is known to have a valuable role in metabolic health, we explored the effect of folic acid on the regulation of the antidiabetic hormone glucagon-like peptide-1 (GLP-1) from endocrine cells. A 24-hour 1.0 mM folic acid treatment produced a 1.690 ± 0.12-fold increase in GLP-1 secretion in a GLUTag-cell line. This research demonstrates that traditional Indigenous foods may have beneficial metabolic effects, and traditional knowledge can inform basic science research.
The effect of hydrogen sulfide on glycolysis-based energy production and mouse red blood cell survival
(2020-12-15) Wondimu, Eden Taddese
Hydrogen sulfide (H2S), a gasotransmitter that modulates physiological and pathophysiological processes, has recently been shown to promote aerobic energy production in the mitochondrion in response to hypoxia. Its effect on anaerobic energy production, however, has yet to be established. Glycolysis is the anaerobic process by which ATP is produced through the metabolism of glucose. The purpose of this study was to establish the effect of H2S on glycolysis-mediated energy production in mouse RBCs, which are mitochondrion-free. This study demonstrated the capacity of mouse RBCs to produce H2S via 3-mercaptopyruvate sulfurtransferase (MST). Both exogenously administered H2S salt (NaHS) and MST-derived endogenous H2S stimulated glycolysis-mediated ATP production. The effect of NaHS on ATP levels was oxygen-independent. However, hypoxic stress stimulated MST activity in mouse RBCs. High concentrations of NaHS (300-1000 μM) prolonged cell viability but reduced ATP levels. H2S may offer a cytoprotective effect in mammalian RBCs to maintain oxygenindependent energy production.
Spatial ecology and variables influencing habitat use and fitness proxies of Eastern hog-nosed snakes (Heterodon Platirhinos) within an anthropogenic landscape
(2022-12-15) Gallon, Alexandria
Changes in environmental conditions and threats from human activities present unique challenges to persistence and management of wildlife populations at range peripheries. For successful recovery and conservation of reptile species at risk (SAR), basic knowledge of their life histories and ecologies must be understood. Such basic information was lacking for a recently reported population of eastern hog-nosed snakes (Heterodon platirhinos) in southwestern Ontario. To successfully meet government-mandated recovery actions for the population of Threatened snakes, I investigated whether hog-nosed snakes’ space use, habitat preferences, and proxies of fitness were impacted by widespread anthropogenic activity in Huron County, Ontario. I estimated movement and home range size (mean ± SD) from locations of hognosed snakes (n = 10) outfitted with radio transmitters from the 2018 to 2020 active seasons, and then calculated using kernel density estimates (KDE) and minimum convex polygons (MCP). I evaluated habitat selection at three scales (i.e., exact, local, and landscape) using resource selection function models and ranked models using Akaike’s Information Criterion corrected for small sample sizes. Proxies of fitness I assessed included quantification of thermal habitat from hourly ground temperatures and snake body condition estimated from residuals of body mass on snout-vent length regressions. I found that when compared to conspecific populations throughout their range, Huron County snakes moved greater distances (49 ± 13 m per day, 127 ± 41 m per move) within larger-sized home ranges (64 ± 30 ha), as well as were heavier and in better body condition compared to conspecific populations near Point Pelee, Ontario. At the coarsest scale, I found that occurrence of snakes in Huron County was positively associated with forest, beach, and old field habitats, while at finer scales, habitat characteristics with structural complexity, cover, and thermal suitability influenced snake occurrence. While proxies of snake fitness did not appear imminently impacted by human activity in Huron County, widespread disturbance did influence how hog-nosed snakes used the landscape: snakes moved greater distances (than those in conspecific populations) to use pockets of natural habitats that were thermally suitable and structurally complex. To ensure effective management of the population stewardship efforts should focus on protection and enhancement of snake habitat and have such actions follow recommendations from this study. My study exemplifies the complex nature of SAR management in Ontario and how understanding space use, habitat selection, and fitness proxies are important to successfully conserving and recovering a snake species at risk.
Speciation of arsenic in freshwater biota
(2023-03-30) Lepage, Adam T.
Arsenic can reach potentially concerning levels in fish and other aquatic biota, but the risk posed is strongly dependent on the element’s chemical speciation. However, the speciation of arsenic in biotic samples remains analytically challenging and freshwater fish, in particular, have not been extensively studied. The limited information available suggests that freshwater fish can have highly variable arsenic speciation patterns, both within and between populations. Based on these knowledge gaps, my thesis has two main goals: (1) to assess the current state of knowledge on arsenic speciation using a systematic literature review and (2) measure arsenic speciation in biota from boreal lakes to investigate drivers of variation among individual fish and invertebrates. My literature review focussed on arsenic speciation in freshwater fish muscle. I identified 39 studies that matched predefined criteria for inclusion based on a review of 1096 potential studies. I found considerable variability in the available literature; although less toxic organic species of arsenic typically dominated in fish muscle, there were reports of fish with high concentrations of the most toxic inorganic species. While studies modeling the drivers of this variation were limited, some suggest that waterbody characteristics, fish size, and trophic ecology may contribute. In my field study, I collected and analyzed fish and invertebrates for two common organic species of arsenic, arsenobetaine (AsB) and dimethylarsinic acid (DMA), in three lakes across a contamination gradient near Sudbury, Ontario. Concentrations of these arsenic species varied widely across fish and invertebrates, generally being found at higher concentrations in the most contaminated system, a lake associated with an abandoned gold mining site. Trophic ecology appeared to be a primary factor affecting arsenic speciation in aquatic food webs, with both AsB and DMA decreasing in concentration with increasing trophic position, inferred from stable nitrogen isotope values. To my knowledge, this is the first study to apply stable isotope techniques to assess how trophic ecology and diet influence arsenic speciation across whole freshwater food webs; where prior arsenic speciation studies have focused on fish alone and did not observe the same biodilution effect. I also identified other factors that may influence arsenic speciation. These included variation in fish size and age, diet, and interactions with co-occurring chemicals (e.g., selenium). However, considerable unexplained differences in arsenic species among taxa remains for further studies to address. Future avenues for research on arsenic speciation include continued improvements in analytical techniques and detection levels, deepening our molecular understanding of arsenic biotransformation and accumulation, broadening toxicological testing of various arsenic species, and assessing the behaviour of arsenic species across diverse food webs. Additionally, improving our understanding of arsenic speciation in freshwater environments is essential to accurately assess risk to consumers or the aquatic biota themselves. A refinement of environmental and human health risk assessments based on the results found herein and in future studies are warranted.

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