Gut microbes help mitigate a major challenge of hibernation Hibernation’s hallmark trait is a profound depression of metabolism that enables animals to survive long periods without eating. This makes hibernation an effective solution to winter’s food scarcity problem; however, it deprives the animal of dietary nitrogen, which is an essential building block for protein. In theory, this should threaten the structure and function of important tissues within the animal, but it has long been known that hibernating mammals avoid this fate and maintain tissue function (e.g., muscle performance) even after many months of fasting hibernation. In this talk, I will discuss our recent work that has revealed how the hibernator’s gut microbes facilitate this tissue preservation and our current work that is investigating how this process may benefit human spaceflight and human health generally.
Aaron Dain MSc, Yakimowski Lab Phenotypic variation of a moderately salt tolerant sunflower (Helianthus annuus) and a halophytic sunflower (Helianthus paradoxus) under extreme environmental salinity Environmental salinity is a global phenomenon that is increasing with anthropogenic change. Salt is toxic to most plants, but less than 1% of plant species are considered highly salt tolerant. Helianthus annuus is considered a moderately salt tolerant glycophyte, although populations occur in the saline Great Salt Lake region of Utah. This raises the question: can populations of glycophytes in saline habitats locally adapt to more extreme salinity? Furthermore, is the range and upper limit of H. annuus within the range associated with its homoploid hybrid descendent, the halophyte H. paradoxus? To investigate variation in the relation between environmental salinity and phenotypic variation, we conducted a common-garden experiment using H. annuus seeds collected from 20 populations of the species’ range with varying concentrations of environmental salinity, and seeds collected from 5 populations of H. paradoxus. Seedlings were treated with control, moderate (field), and high (field x2) salinity treatment solutions mimicking the ionic composition of H. paradoxus habitat. Phenotypic traits related to salt tolerance (above- and below-ground biomass, plant height, and growth rate) of juvenile plants were measured and compared among populations and treatment groups. Quantitative soil salinity data was collected for ten of these populations, and used to investigate the relation between environmental salinity and salt tolerance. In the Great Salt Lake region soil salinity (% sodium) ranged from 1.3 to 37.9 (n = 26 populations); thus, high-saline sites exhibit salinity in the range associated with its halophytic relative H. paradoxus. Under non-saline conditions, H. annuus plants originating from non-saline habitats are larger than those originating from saline habitats. However, under field-like salinity, saline-originating H. annuus plants retain more biomass than non-saline originating plants. H. paradoxus plants are smaller than H. annuus under non-saline conditions but are larger under field-like salinity. This suggests biomass is shaped by environmental salinity. In comparison, growth rate and plant height do not significantly differ between saline- and non-saline H. annuus populations, and those from populations with the highest salinity grow more slowly than those from populations with lower salinity. Additionally, H. paradoxus plants grow more slowly than H. annuus plants. This suggests that plant height and growth rate are not shaped by environmental salinity in the same way, and that growth rate may not be selected for in saline habitats.
Damian Bourne MSc Student, Colautti Lab Morphometric variation in Ixodid ticks at an expanding range edge Ixodid ticks (Acari: Ixodidae) are important vectors of zoonotic disease that have devastating impacts on human health and well-being. Therefore, it is essential that effective monitoring protocols be put into place to map tick abundance and richness within certain areas. Although research into the most important tick species across Eastern, Ontario is abundant, up-to-date studies looking into the morphological features that contribute to observed diversity are lacking. Geometric morphometrics is a powerful tool that allows researchers to compare shape variation between groups. This study utilizes geometric morphometrics to survey important tick species within Eastern Ontario and explore the morphological diversity that defines them. A total of 518 ticks were sampled over a 6-year period representing two medically important species known to harbour harmful pathogens: D. variabilis and I. scapularis. Morphometrics utilizing principal component analyses of these two species found that the chosen common dorsal and ventral landmarks accurately categorized individuals by their respective species and sex. Furthermore, I. scapularis females showed significantly different morphologies across locations possibly representing diverse environmental pressures that need to be considered in management protocols. Supervised machine learning algorithms were also utilized and found that the selected landmarks accurately assigned individuals to their respective groups. Additionally, this analysis identified individuals with abnormal morphologies that may represent novel or cryptic species. Future research should combine both morphometric and genetic approaches to increase the robustness of species identification and provide additional evidence for tick diversity that may lead to better mitigation and management solutions for these critical vectors of zoonotic disease.
Accelerating freshwater restoration science & practice through community-engaged research The UN Decade of Ecosystem Restoration (2021-2030) calls for an accelerated need to cooperate at local and global scales to heal our degraded planet, and that the best examples of restoration success have been community-led. Through research situated in watersheds impacted by settler-dominated agricultural intensification and urbanization, Dr. Febria will describe how farm-focused and Indigenous-led partnerships have led to richer outcomes in addition to Western-science outcomes, all of which are crucial for freshwater restoration science and its’ translation into practice and decision-making. Research on molecular and microbial properties of headwater stream ecology and community ecology of Unionid species-at-risk will be discussed as examples of how projects in the Healthy Headwatesrs lab centre human dimensions to inform the science pursued across watersheds in the Laurentian Great Lakes and our shared home known as Turtle Island/North America. Drawing on additional examples globally, this talk will demonstrate how ethical and equitable research partnerships can support a more effective and actionable science, in support of a just and sustainable freshwater future.
Non-Academic Guest Speaker Exploring the art of delivering science in the Canadian Artic: mistakes made and lessons learned When visiting university departments over the years, I’ve had the pleasure of meeting with many graduate students and Post-Doctoral researchers. At an early career stage in their career, discussions were narrowly focused on science approaches, new findings, and graduate thesis completion. This seminar intends to get people thinking beyond that, and to consider what it takes to build and lead a successful science team of your own. Drawing on my own experience conducting research in the Arctic, I will discuss topics such as how to recruit and retain the best people, establish collaborations, and identify the ‘performance measures’ of science (including, but not limited to, publication). Importantly, I will provide examples of where I made mistakes and the consequence of those, and how I spotted research and collaborative opportunities.
Dr. Edel Pérez-López Département de Phytologie, Université Laval Strawberry-leafhopper-phytoplasma, a pathosystem under siege by climate change Food security is threatened by climate change, directly through the response of crop productivity, and indirectly through the relationship of crops with plant pathogens and pests. In Quebec, strawberry growers have been noticing how in the last few years the number of insect pests have been increasing every summer, especially leafhoppers, members of the family Cicadellidae known vectors of virus and bacterial diseases. To understand these observations, we have been investigating for two years the diversity and abundance of leafhoppers in strawberry fields in the main producer areas of the province. In parallel, we have been also investigating the presence and distribution of strawberry green petal disease, a disease caused by bacterial pathogens transmitted by leafhoppers, and the role of those insects as vectors of the disease. In this seminar I will present the results of these two years of work finding an unexpected diversity of leafhoppers including eleven new reports for East Canada, an increase spread of strawberry green petal disease in Quebec fields, and evidence that new pathogens might be affecting soon strawberry fields in Canada, all this probably orchestrated by global warming.
Christina Steinecke MSc Student, Friedman Lab Selection and genetic constraints on clonal investment in a perennial plant Many plant species can reproduce both clonally (for example, via stolons or corms) and sexually via flowers and seed. The question, then, is why some plants invest resources into both, and whether phenotypic and genetic correlations exist when investing in traits associated with one mode or the other. The relative importance of the two modes of reproduction likely vary in different ecological conditions, but to what extent can selection drive different investment strategies? A population’s ability to respond to selection on clonal investment might impact its capacity to respond to environmental change. Furthermore, genetic correlations between traits can either facilitate or constrain evolutionary responses depending on the direction and strength of selection. Here, we investigate the capacity for clonal investment to respond to high or low truncation selection in a perennial population of Mimulus guttatus. The aims of our research are to first quantify the magnitude of phenotypic responses to artificial selection on clonal growth, and then to identify traits that respond in concert due to underlying genetic correlations. To address these aims, we first established an outbred population from field collected seed in a greenhouse, and then imposed four generations of divergent, truncation selection on clonal growth for two replicate high lines, two low lines, and a control line. We used quantitative genetics and pedigree analyses to investigate additive genetic variance, heritability, and the response of clonal growth through time. We then investigated genetic correlations among life history traits measured throughout the life cycle to identify whether genetic constraints might constrain evolutionary trajectories. Our results showed that selection elicited the predicted divergent response in clonal growth; however, low-clonal lines respond more strongly to selection compared to high-clonal lines. Decreased clonal growth was also negatively correlated with a suite of traits including overall size, flower number, and flowering time. These findings suggest unequal additive genetic variance in the low-clonal and high-clonal lines, and indicate that populations have greater capacity to reduce clonality in the face of selection, and that increases in clonal investment might be more difficult. This study tests a classic, yet unresolved, evolutionary question and suggests populations harbour sufficient standing genetic variation to respond rapidly to selection but that the underlying genetic architecture and trait covariation could constrain evolutionary trajectories and adaptive divergence
Jeffrey Dason, Department of Biomedical Sciences, University of Windsor Activity-dependent cholesterol redistribution is required for synaptic growth Synaptic plasticity is a fundamental property of neurons that allows their ability to transmit information to change with experience. Numerous studies have examined how synaptic plasticity is regulated by protein–protein interactions and changes in the expression and activation of various proteins. In contrast, the roles of lipids in synaptic plasticity have been less studied. Increasing evidence suggests that the lipid content of neuronal membranes does not remain constant and is altered by synaptic activity. The Drosophila larval neuromuscular junction is a well-established model system for studying synaptic growth and shares the basic molecular components found at most synapses. We generated transgenic flies that express the cholesterol binding D4H domain of Perfringolysin O toxin fused to GFP and found increased levels of cholesterol in presynaptic terminals of glutamatergic Drosophila neuromuscular junctions following periods of increased synaptic activity. We found that cholesterol is required for both synaptic growth and activity-dependent synaptic growth. Examination of several mutant and transgenic larvae reveal that cholesterol is likely regulating synaptic growth through the cAMP-PKA kinase signaling pathway. Collectively, our data demonstrates that cholesterol redistribution occurs in response to synaptic activity and that it plays a key role in development and activity-dependent synaptic plasticity.
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