Emilie Norris-Roozmon
MSc Candidate, Colautti Lab Associations among self-reported tick-borne disease symptoms, treatments & diagnoses In eastern Canada, deer ticks (Ixodes scapularis) carry a variety of bacterial (Borrelia burgdorferi, Anaplasma, Ehrlichia, Rickettsia) and protozoan pathogens (Babesia) that are responsible for more disease in humans than any other arthropod vector. While most known tick-borne diseases (TBD) in Canada are treatable, invasions of new pathogens may go undetected for decades or more. Misdiagnosed and untreated infections can cause debilitating symptoms, many of which are non-specific and can be mistaken for other diseases. Using quantitative models, the goal of my thesis was to investigate whether tick-borne diseases cause syndromes (e.g., groups of symptoms which consistently occur together). I used supervised machine learning models of self-reported symptoms while accounting for demographic characteristics, clinical tests, and chronic health conditions. An anonymous cross-sectional survey was disseminated online via the Qualtrics software package to survey age, gender, blood test results, symptom profiles, and chronic health conditions. Recruitment was focused on the Kingston-Ottawa corridor because it is a Lyme disease hotspot in Canada, but inclusion criteria included anyone with a self-reported tick bite. This resulted in 1248 unique submissions, 301 of which self-reported a tick-borne disease diagnosis. On average, participants who reported a Lyme disease diagnosis along with one or more secondary co-infections presented with more symptoms and a longer time to diagnosis than participants with Lyme disease alone. A Regularised Discriminant Analysis of 13 binary symptoms correctly classified participants with 98% accuracy into self-reported diagnoses grouped into four categories: Lyme disease, Lyme with one or more co-infections, other tick-borne disease, and no diagnosed disease. To model how healthcare practitioners might diagnose disease, I used hierarchical logistic regressions to identify self-reported factors that predict diagnosis. Skin rash and blood tests were predictive of all three diagnosis categories, accounting for 41-61% of the variation in TBD diagnosis predictions. Participants with chronic health conditions (cardiovascular, rheumatological, and central nervous system disorders) were less likely to receive tick-borne disease diagnoses, which is consistent with misdiagnosed disease. My research shows how symptom profiles can help to understand tick-borne diseases, representing a collaborative approach between scientists and patients that can help to improve diagnosis and knowledge translation in the domain of tick-borne disease. Liying Xu
MSc student, PEARL Lab Understanding spatial patterns of past aridity on the Canadian prairies over the Holocene: Insights based on diatom assemblages from Success Lake The Canadian prairies receive limited precipitation and hence are prone to drought-related environmental, economic, and social impacts. Previous studies have suggested the Canadian prairies are highly subject to extreme drought in the future that resembles the mid-Holocene,which is when many lakes have dried out. Understanding the Holocene aridity profile is critical for us to be able to confidently forecast future drought and aridity, which is essential to establish appropriate policies and programs to reduce negative impacts. I used diatom outer scales buried in Success Lake sediment to reconstruct changes in lake water salinity, which could indicate the change in the aridity over the Holocene on the Canadian prairies. Diatom record from Success Lake revealed four stages of aridity change in its vicinity over the Holocene. Century-scale analysis of the diatom record during the Holocene is consistent with a drier climate in the early-mid Holocene (between 7000 to 5300 yr BP). An abrupt decrease in diatom-inferred salinity between 5300 cal yr BP to 3300 yr BP indicates the onset of a wetter climate, with continuing arid conditions throughout the mid-Holocene. Analysis of the past ~3000 years suggests that the late Holocene was more complex, with extended periods of increased variability in precipitation, characterized by frequent oscillation between the rise and falls in effective moisture. Comparing the aridity record from Success Lake with other paleoclimatic records from the Canadian prairie revealed a west-east moisture variability gradient, showing coherency within western and eastern sites and with opposite trends among the two groups. The mechanism controlling the moisture gradient is likely associated with the positioning and shaping of the jet stream, influenced by ocean-atmospheric interaction and solar radiation. Natural shifts in moisture availability may accelerate global warming, further reducing the precipitation and intensifying the likelihood of extreme drought over the Canadian prairie. Jordan Balson,MSc Candidate
Lefebvre Lab & Environment Physiology and Freshwater Ecosystem Lab Assessing the potential of Caenorhabditis elegans in the bioremediation of M. aeruginosa Reported incidences of cyanobacterial harmful algal blooms, or CHABs, are increasing across the world due to climate change and nutrient loading. CHABs can produce dangerous cyanotoxins and dominate freshwater ecosystems. Microcystis is one of the most common types of cyanobacteria and can produce microcystins. The ecological and human impact of algal blooms are immense, costing $7.8 billion in loss of ecosystem and market asset values in Lake Erie alone. A proactive, targeted approach is needed to bioremediate CHABS. Bioremediation of CHABs with Viviparus georgianus (the banded mystery snail) is somewhat effective, as the snail filter feeds and ingests intact cyanobacteria cells, which are then translocated to the benthos in pseudofeces. Although this keeps cyanobacteria from entering its disruptive colonial phase, this is temporary, as currents eventually liberate the live cyanobacteria cells. Nematodes, such as Caenorhabditis elegans and its relatives, are potential candidates for bioremediating these cyanobacteria-containing pseudofeces in combination with the banded mystery snail. C. elegans have been shown to have detoxification pathways, which may break down microcystins. As well, cyanobacteria have been found in C. elegans’ microbiome, making it likely that they ingest cyanobacteria in nature. We aim to examine the potential of C. elegans for multi-stage bioremediation of Microcystis. We aim to evaluate the potential of C. elegans to ingest, digest and detoxify Microcystis and pseudofeces; as well, we aim to determine what impacts this diet has on C. elegans’ health. We hypothesize that nematodes are viable organisms for bioremediating CHABs in combination with V. georgianus and that nematodes will be able to ingest, digest and detoxify Microcystis cells contained within snail pseudofeces. Sarah Beech, MSc Candidate
Environment Physiology and Freshwater Ecosystem Lab Spatial ecology of two Lake Whitefish spawning aggregations in Lake Ontario and the Bay of Quinte Lake Whitefish (Coregonus clupeaformis) in the Laurentian Great Lakes have experienced overexploitation by commercial fisheries and major ecological changes throughout the past century. In Lake Ontario, the Lake Whitefish population was severely reduced and has shown minimal reproductive success since the 1990’s. In Canadian waters, two major spawning aggregations persisted in the eastern basin and currently support a commercial fishery. The declined state as well as the socio-economic and ecological importance of this species has emphasized the need for current research and knowledge. Using acoustic telemetry, this project analyzed the spatial distribution and movement patterns of two spawning groups of Lake Whitefish in Lake Ontario and the Bay of Quinte. Spatial analysis revealed clear differences in space use between the spawning groups. The spatial discreetness observed between the spawning groups suggests differences may exist in commercial exploitation and factors related to bioenergetics such as diet and energy expenditure. Understanding the current behaviour and ecology of Lake Whitefish will also be important for management of the commercial fishery and future conservation efforts. Phinyaphat Srithiphaphirom, PhD Candidate Department of Biology, Robertson Lab, Queens' University Rapid cold hardening and stress-induced spreading depolarization in the central nervous system of Locusta migratoria Rapid cold hardening (RCH) is a short-term hormesis in which brief chilling (minutes to hours) significantly enhances the stress tolerance of an animal. Insects live in varied habitats and thus experience different kinds of environmental stresses. To thrive, insects enter a reversible coma, or hypo-energetic state when they are under stress. This is associated with a sudden loss of ion homeostasis and temporary shutdown in the central nervous system (CNS), which is a hallmark of spreading depolarization (SD). Insectstress tolerance is dependent on the sensitivity of their nervous systems to unfavourable conditions, which can be modulated by RCH. Using pharmacological and electrophysiological approaches, we investigated the mechanism of RCH and its effect on stress-induced SD in locusts, Locusta migratoria. We showed that RCH delays the onset of both chill- and anoxia-induced SD. Octopamine (OA) is an insect stress hormone, and we showed that OA mimics, whereas its antagonist, epinastine (EP), blocks, the effect of RCH on chill- and anoxia-induced SD. Thus, we concluded that OA mediates the RCH-induced delay of the onset of anoxia-induced locust coma. Lastly, we investigated whether RCH affects anoxia-induced SD via one or more of the following homeostatic mechanisms that are involved in maintaining K+ gradients: Na+ /K+ -ATPase (NKA), Na+ /K+ /2Cl- co-transporter (NKCC), and voltage-gated K+ (Kv) channels. We showed that NKA and Kv channels (excluding the Shaker family) modulate SD occurrence and possibly take part in the mechanism of RCH, whereas NKCC is directly involved in the mechanism of RCH. Altogether, we suggested that RCH regulates NKA, NKCC, and Kv channels through an octopaminergic pathway to modulate stress induced SD in locusts.
Michelle Kong, MSc. Candidate Department of Biology, Wang Lab, Queen's University Measuring the efficiency of bioremediation of cyanobacterial harmful algal blooms With rising global temperatures, harmful algal blooms have been increasing in size and frequency for several decades. These blooms produce and release toxins while severely reducing the oxygen levels of marine and freshwater ecosystems, resulting in large scale mortality events of aquatic life. Cyanobacterial harmful algal blooms (CHABs) produce cyanotoxins, which have caused poisoning cases of aquatic life, agricultural animals, and humans alike. A key element in a proactive approach to controlling CHABs may be bioremediation, which is the use of naturally occurring organisms to consume environmental pollutants. Viviparus georgianus, the banded mystery snail, is ubiquitous to freshwaters, naturally occurs in high densities, and can safely ingest cyanobacteria with high tolerance and rapid detoxification effects, making them an ideal candidate for use in bioremediation. However, little is known about their consumption, their rate of consumption, and how it may be affected by the species of cyanobacteria present and density of snails. We placed V. georgianus in microcosms with varying species of cultured algae or cyanobacteria, as well as varying densities of snails and then measured the quantity of cyanobacteria ingested via chl-a levels. Through this, we were able to observe V. georgianus’ consumption of cyanobacteria at a similar efficiency to green algae, as well as significant drops in chl-a with as little as 3g of snails per 200mL of water. By understanding how to optimize V. georgianus’ consumption of cyanobacteria, we can make use of a widespread and highly populous species for efficient and effective inhibition of bloom growth.
Samreen Munim, MSc Candidate
Department of Biology, Martin Lab, Queen's University Do acoustic signals diverge or converge where geographic ranges overlap? Closely related bird species often have similar acoustic mating signals because of their shared recent ancestry, which can affect their reproductive isolation and ability to live together when they overlap in range. Mating signals are mostly used to attract mates and interact with competitors of the same species, but closely related species can also respond to these signals, which can lead to costs of co-occurrence, both direct (e.g., hybridization, aggression) and indirect (e.g., as a by-product of ecological divergence). As a result, where closely related species overlap in range, we expect mating signals to diverge to minimize these costs. However, the opposite can also occur: signals may converge in sympatry (i.e., range overlap) because of similar selective pressures from the environment, or from introgression or cultural drift. Moreover, selection to reduce aggressive encounters can also lead to convergence. Whether signals more often diverge or converge when species overlap in range is poorly understood, particularly for acoustic signals. To address this gap, I used a comparative framework wherein each comparison involves a pair of closely related sister lineages that differ in whether they overlap in range with a third, more distant lineage within the same genus. For each comparison, I found recordings of birds and compared the signals of the sympatric pair of species to the allopatric (i.e., no range overlap) pair to see if acoustic signals more often diverge or converge when closely related species overlap in range. The results of this study will help us better understand signal evolution and the maintenance of species barriers in sympatry, with consequences for the broad patterns of biodiversity we see in nature. |
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