3A12 Abstracts

Below is a list of abstracts by third-year students in the Integrated Science Program:

POSTER PRESENTATIONS – MARCH 30, 2017

Charlotte Tousaw: Expanding the Scope of Research Project 4

Supervisor: Dr. Chad Harvey

Over the past seven years, first year Integrated Science students have had the opportunity to research the topic of cancer. Each student would research a specific type of cancer, and also write a review paper with a group which outlines a step in the process of cancer diagnosis or treatment. It is important to note, however, that cancer is not the only disease affecting the 21st century society. So, there is great potential to expand this project to incorporate other important diseases. This new project model will include a wider range of diseases, allowing for more student choice within the project, and the opportunity to research a topic with which they may not already be familiar. The content and format of continuous assessments and final deliverables have been re-designed to increase the interdisciplinarity and clarity of assessment in the project. With the new project model, students will learn about a broader spectrum of disease and epidemiological science. In addition to the individual review article, in small research groups, students will develop a rigorous research proposal to increase our understanding of their chosen disease topic. The ultimate outcome of this re-design will improve student health literacy and help instructors to better align assessment criteria associated with each scientific discipline.

Kyra Simone: Emerald ash borer incidence and infestation at McMaster Forest

Supervisor: Dr. Chad Harvey

The emerald ash borer (EAB), Agrilus planipennis, poses great risk to Canadian ash trees. International trade may have introduced this China-native pest to North America, where it now threatens forested areas, urban shade trees, and some manufacturing and shipping industries. Furthermore, its interferences with the interactions of native species have the potential to initiate ecosystem-wide cascades. The purpose of this study is to determine the current state of EAB infestation at McMaster Forest Teaching and Research Facility in Hamilton, Ontario, and to elucidate any potential relationship between EAB distribution and ecological factors. The prevalence of ash trees and the number of ecosystems represented (14 different regions, distinguished by specific ecological factors) make this an ideal study site.The back, forested area of the site is divided into 20-by-20 metre quadrats. In five randomly selected quadrats in each ecological class, every ash over 5 cm in diameter at breast height (DBH) will be surveyed. Data collected will include DBH measurements, tree location (GPS coordinates), height of lowest exit hole above the ground, rough exit hole counts, and visual observations of tree health. EAB decrease ecosystem stability through competition with native borers, alteration of both canopy and understory environments, and thus interference with nutrient cycling and successional processes. This study aims to assess the current state of EAB infestation in the McMaster Forest, and to provide a better understanding of EAB distribution in relation to ecological factors.

Supriya Singh: Measuring Aerosols in the GTA during the 2015 PanAm/ParapanAm Games

Supervisor: Dr. Jennifer Murphy

The Earth’s atmosphere is a complex system composed of gases, aerosols, and is also a medium for chemical reactions to take place. Particulate matter (PM) is the term used to describe atmospheric aerosols or particle pollution that can emerge from both natural and anthropogenic sources. The colour, size, and composition of PM are all important factors that determine the associated risk factors. Overall, PM alters the albedo of the Earth, which causes an increase in health issues. Highly populated urban and industrial areas are hotspots for anthropogenic aerosols and are especially at environmental risk. This study analyses the mobile concentrations of PM2.5 in the General Toronto Area (GTA) during the 2015 PanAm/ParapanAm games for the Environment Canada PanAm Research Showcase. Mobile meteorology data was collected using Environment Canada’s automated mobile meteorological observation system (AMMOS) vehicles in which two PM2.5 mobile measurement devices are set up. The AMMOS vehicles travelled down three main routes (Yonge, Warden, and Dufferin) from Lakeshore to King City several times throughout each day for nine days. The data was georeferenced, time stamped, and analysed through the production of maps. These maps display the varying concentrations of PM2.5 across the GTA throughout the day. Results depict that mass concentration of PM2.5 increased south of the GTA for AMMOS routes (dependent on time) and particle count displayed no distinct trend throughout the day. These findings overall contribute to improving micrometeorological techniques, and is an example of how mobile air quality data collection provides more insight and maps the spatial variability of data.

Loryn Byres: Exploring the Interplay Between Lsr2 Proteins in Streptomyces venezuelae and Their Role in Controlling Antibiotic Production

Streptomyces are a soil-dwelling genus of the Gram-positive actinobacteria, capable of producing most naturally synthesized antibiotics. Lsr2 is a small nucleoid-associated protein that is well conserved throughout actinobacteria. It functions as a dimer and is involved in the transcriptional repression of a wide variety of genes, including those involved in antibiotic production in StreptomycesStreptomyces are unique in that they possess two copies of the lsr2 gene: lsr2-I, believed to be the original gene, and lsr2-II, thought to have resulted from a duplication of lsr2-I. Current research has focused primarily on the role of lsr2-I; however, lsr2-II merits further investigation as its conservation throughout Streptomyces suggests that it may be advantageous to the cell. Our objective is to increase our understanding of the role of Lsr2 in gene regulation in Streptomyces.

As a first step towards elucidating the functional role of both Lsr2 proteins, the physical interactions between Lsr2-I and Lsr2-II will be probed in vivo, using bacterial two-hybrid analyses. The two genes will be reciprocally cloned into the two-hybrid vectors, and the intraspecific and interspecific interactions between the two proteins will be tested in a pair-wise manner. One hypothesis is that the Lsr2-II protein may be capable of forming both homodimers with itself, and heterodimers with Lsr2-I, and that these associations may alter both the proteins’ function, and the cell phenotype. Lsr2 may be an effective target to increase antibiotic production in Streptomyces, making it important to more fully understand the roles both genes play in the cell.

Martyn Siek: Functional Predictability of FEV1 in COPD Patients

Supervisor: Dr. Mylinh Duong

Chronic Obstructive Pulmonary Disease (COPD) is a non-contagious irreversible lung disease that is characterized by poor airflow and typically worsens over time. The disease includes symptoms such as coughing, wheezing, shortness of breath, sputum production, and inflammation of the airways, and as a result can be very debilitating. COPD is most commonly diagnosed using spirometry which produce values such as forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and forced residual capacity (FRC). The severity of a patient’s COPD is then determined by comparing to predetermined percent predicted values for the patient’s sex, age, height, and ethnicity. Despite the effectiveness of this method when diagnosing COPD, the interaction between spirometry and disability caused by the disease is not well understood. This study aims to determine whether spirometry and the values it produces to measure COPD debilitation, specifically FEV1, positively correlate with daily walking time and physical activity intensity using the DynaPort MoveMonitor. With the exception of a few studies, the use of PA measurement with an activity monitor is a novel method in quantifying the debilitation of the disease. PA is a good predictor of survival in the general population, and data has been collected to indicate an independent association between PA, hospitalizations, and mortality. Low PA is also correlative with markers of systemic inflammation, and patients with COPD have been shown to have significantly lower levels of PA compared to elderly volunteers.

Meena Al Saigh: The Use of Oncolytic Viruses in Combinational Cancer Immunotherapy

Supervisor: Dr. Yonghong Wan and research assistant Donald Bastin.

Oncolytic viruses (OVs) are an emerging form of cancer immunotherapy which have shown promising results in both preclinical and early clinical trials1,2,3. This new treatment modality is based on the intrinsic or engineered ability of viruses to selectively target, replicate in, and lyse tumor cells4. In addition to their oncolytic properties, OVs have the ability to stimulate an antitumor immune response following tumor-cell death or “immunogenic cell death” (ICD)2. This study aims to provide a complete literature review on the mechanism of action of OVs and their synergistic effects when used in combination with different types of immunotherapies. A majority of the research will be conducted by reading primary and secondary scientific articles using PubMed as the main search engine. The review article will be submitted to the Journal of Biomedicines for peer-review. In doing so, we hope to clearly convey the clinical significance of oncolytic viruses and their use as immunotherapeutic agents in the on-going fight against cancer.

References:

  1. Melcher, A., Parato, K., Rooney, C. M. & Bell, J. C. Thunder and lightning: immunotherapy and oncolytic viruses collide. Mol. Ther.19, 1008–16 (2011).
  2. Zamarin, D. et al.Potentiation of immunomodulatory antibodies with oncolytic viruses for therapy of poorly-immunogenic tumors. J. Immunother. Cancer 2, P132 (2014).
  3. Chiocca, E. A. & Rabkin, S. D. Oncolytic viruses and their application to cancer immunotherapy. Cancer Immunol. Res.2, 295–300 (2014).
  4. Davis, J. J. & Fang, B. Oncolytic virotherapy for cancer treatment: challenges and solutions. J. Gene Med.7, 1380–9 (2005).

Angelico Obille: Investigating methods of functionalizing cellulosic materials

Supervisor Name: Dr. Jose Moran-Mirabal

Cellulose is a naturally produced biodegradable polymer of glucose with high structural integrity. As an abundant resource, ongoing research seeks to create cellulose-derived composites that can effectively replace non-biodegradable materials. Methods of functionalizing cellulose in the forms of cellulose nanocrystals and paper to alter its properties are investigated. To date, cellulose has been modified with various moieties such as poly-ethylene glycol, benzene, and allylamine. Of particular interest is allylamine functionalization because the exploitation of the double bond allows for a wide range of applications in modifying cellulosic materials. Specifically, the reaction between thiols and allylamine, namely thiol-ene reactions, allows for the ability of these thiols and their accompanying chemical and mechanical properties to be “clicked” onto the cellulosic material. Octadecanethiol, a hydrophobic thiol and mercaptohexanol, a hydrophilic thiol, are two thiols that have been shown to be clicked onto the allylamine-treated cellulosic materials. Various characterization techniques are performed to verify the results of this project. To verify the successful synthesis of the allylamine derivative that is to be added onto cellulose, nuclear magnetic resonance spectroscopy and mass spectrometry are performed. The products are integrated onto paper in which the thiol-ene click chemistry is then employed. To prove that cellulosic modification has been successful, contact angle measurements reflect that the clicking of octadecanethiol increases the hydrophobicity of the paper and that the clicking of mercaptohexanol increases its hydrophilicity. The results of this project show promise in the use of thiol-ene click chemistry to modify cellulose with a wide range of applications.

James Lai: Peer Blogging Feedback in the Development of Written Communication Skills in the Integrated Science Program

Supervisor: Andrew Colgoni

One aim of McMaster University’s Integrated Science (iSci) program is to develop students’ science communication skills. To this end, students write scientific blog posts and provide one another feedback for improvement. Although the benefits of peer feedback have been noted in the literature, aspects of iSci’s blogging exercise merit closer examination. The aim of this study was to examine how commenting frequency changes in response to other iSci deadlines, and whether the amount of feedback received correlates with quality improvement. Differential commenting over time could impact the educational benefits to different students: due dates are currently randomly assigned. The number of comments made each day during the 2013-2014 and 2014-2015 school years was compared to a list of project deadlines. Subsequently, a random subset of posts was examined for whether the amount of feedback received correlates with quality change between the first and final drafts. Due to time constraints, this study only examined whether technical elements of writing (spelling, grammar, and complexity) are affected; elements such as style were not considered. Thus, spelling and grammar errors, and readability statistics, formulae that output a grade level based on values such as sentence and word length, were recorded. It is expected that greater improvement in blog post quality will be observed in posts that receive more feedback, and that commenting rate will decrease near due dates in other parts of the iSci curriculum. If this is confirmed, modifying the assignment may be warranted to offer all students equal educational experiences.

Tristan Goodwill: Implementing Three 2RDM N-Representability Constraints through Semidefinite Programming

Supervisors: Dr. Randall Dumont and Dr. Paul Ayers

The ground state of an N-particle system determines many of the properties of the associated matter, and sets the stage for others. In general, iterative approaches are required to calculate this ground state. Current methods, such as the Hartree-Fock method and the full configuration interaction, either return inaccurate values when the electronic system is highly correlated or scale too quickly with N. Constructing reduced density matrices (RDMs) is a promising alternate method because it inherently deals with electron correlation. The order of the method is only a polynomial in the number of basis functions used, so it scales as a power of N. Specifically, the 2 electron RDM (2RDM) is the smallest RDM that has the same measurable properties as the true ground state, since electrons interact in pairs. Therefore, the method is exact up to the Born–Oppenheimer approximation, while being computationally efficient. Unfortunately, ensuring that a 2RDM corresponds to an N electron density matrix is challenging. In this project, we develop a simplex-like algorithm for calculating the 2RDM implementing three representability constraints, which ensure that the electron pair 2RDM, the hole pair 2RDM and the electron-hole 2RDM are all positive semidefinite. We then implement this algorithm in Python 3.5 and test it for a simple 4 electron system. We hope to minimize the degree of the scaling polynomial so as to make the 2RDM method competitive with other methods, while properly handling electron correlation.

Deep Inamdar: The Eco-evolutionary Dynamics of an Emerging Pathogen in a Seasonal Environment

In the study of evolution, virulence is a property that describes the ability of a pathogen to reduce host fitness. The property is dependent on many factors and can vary drastically, even amongst seemingly identical host-parasite interactions. Scientists do not fully comprehend the mechanism and motivation of parasite virulence evolution. Much of the modern theory on pathogenic virulence is based on the trade-off hypothesis and attempts to predict the evolutionary dynamics of virulence in emerging pathogens that approach a stable equilibrium. To date, very few studies have developed theories that deal with pathogens within a seasonal environment that do not approach a static evolutionary equilibrium. The purpose of the study was to analyse the evolutionary dynamics of a model pathogen in a seasonal environment. The analysis uses a simple SIS model that was modified to modulate virulence and transmission rate sinusoidally over time. The basic simulation protocol ran the model with a factorial combination of three seasonal parameters: the frequency, amplitude, and phase shift of the sinusoidal forcing factor. For each simulation a variety of summary values were calculated: the maximum virulence, timing of the maximum virulence, long term virulence, and the long term population dynamics of susceptible and infected individuals. The simulation results correlated both the frequency and amplitude with all of the summary values. There was no strong relationship between the phase shift and the summary values.  Overall, the finding suggest that the seasonal component of the environment plays large role in the evolutionary dynamics of pathogen virulence.

Jesse Provost: The Million-Dollar Question: Navier-Stokes Equations

The Navier-Stokes equations describe the motion of a fluid in Rn. To solve the equation, one must solve for the fluid velocity vector and the pressure function. The proof for the existence and smoothness of the Navier-Stokes equations in is an open problem to this day, and if anyone ever solves it they are rewarded with the Clay Prize and $1 million. Many mathematicians and physicists believe that by fully understanding the Navier-Stokes equations we would justify and have confidence in our modeling of complex flows such as turbulent air currents. This report will look into the full 3-D problem and the progress that has been made. It starts with a derivation of the Navier-Stokes equations from first principles, then looks into both the 1-D and 2-D analog equations, and finishes with some analysis of the full 3-D problem. The Navier-Stokes equation in 1-D is the same as viscous Burgers’ equation. The Hopf-Cole transform can be used to turn viscous Burgers’ equation into the heat equation, which can easily be solved by convoluting the transformed initial data with the heat kernel. The proof for the maximum principle of viscous Burgers’ equation is also given. By taking the curl of the Navier-Stokes equation we get the vorticity equation, which describes the local rotation of a fluid. In 2-D, the evolution of vorticity also satisfies the same maximum principle. For the full 3-D problem, three topics are discussed: the indicators of solution breakdown, and upper and lower bounds on hypothetical singular sets.

ORAL PRESENTATIONS – MARCH 31, 2016

Biran Falk-Dotan: Self-Regulation and Exercise Adherence in Younger and Older Adults

Supervisor: Dr. Jennifer Heisz

Participation in physical activity is among the chief factors influencing human health, including bone, cardiovascular, and mental health. Unfortunately, most Canadians do not meet the Canadian Society for Exercise Physiology guideline of at least 150 minutes of moderate to vigorous exercise per week. Previous research suggests that exercise self-efficacy (confidence in one’s ability to successfully complete the exercise program) increases with some aspects of executive functioning (namely, task co-ordination and impulse inhibition), leading to increased exercise adherence. This project explores the relationship between adherence to an unsupervised exercise program and cognitive traits related to self-regulation, including executive functioning and exercise self-efficacy. After an initial battery of questionnaires and executive functioning tests, younger and older adult participants are tasked with completing at least 150 minutes of exercise per week for 4 weeks. We use structural equation modelling to assess the dependence of exercise adherence on self-efficacy and executive functioning, as well as affect and motivation for exercise. We predict that participants with better performance on executive functioning tasks will have higher exercise self-efficacy and consequently higher adherence to the exercise program. This study will help elucidate the cognitive variables underlying exercise adherence, which may allow for more effective strategies to be used in the future for increasing exercise adherence in the sedentary population. These may include targeted self-regulation strategies, based on key executive functions, to increase adherence.

Eva Clark-Lepard: Development of the Sexual Self-Efficacy and Attitudes Questionnaire for use at McMaster University

The value of sex education is currently under fire. With Ontario’s new sexual education curriculum being met with opposition and Republicans vouching for reduced funding of sexual education resources across America, it is more important now than ever to illustrate the positive impact of sex education at all levels of education. There is a substantial amount of literature examining the impact of human sexuality courses on undergraduate students’ attitudes and self-efficacy (confidence in the completion of tasks) related to human sexuality. However, many of the surveys used in these studies use outdated language. The goal of this project is to create a survey targeted at students ages 17-22 years old with questions that are updated in regards to the change in societal views surrounding human sexuality since the creation of previous surveys. This survey aims to measure self-efficacy and attitudes towards human sexuality that include questions under the categories of communication, sexual anatomy and physiology, contraceptives, STIs, pregnancy options, consent, sexual orientation, masturbation, and paraphilia. This project is being continued as a thesis starting in September 2016, when the survey will be administered and the data collected and analyzed. This survey will be administered at the beginning and end of term in the two courses at McMaster University that are focused on human sexuality: Human Sexuality (PSYCH 3CA3) and The Biopsychology of Sex (LIFESCI 4X03). We expect that our results will mirror those in current literature; at the end of term students will be more accepting of sexual diversity and more confident in their ability to be self-sufficient in regards to their sexual health after being exposed to the content of these courses.

ORAL PRESENTATIONS – MARCH 31, 2016

Lucia Krivankova-Smal: Nd isotope mapping of tectonic windows: Huntsville area

Supervisor: Dr. Alan Dickin

The Grenville Province results from a ca. 1 Ga continental collision, which caused a large thrust sheet to be exhumed from the deep crust and then to be transported horizontally, giving rise to a ramp flat thrust architecture. Subsequently the crust underwent folding and erosion, leaving a complex pattern of tectonic ‘outliers’ and ‘windows’. When the underlying crust (parautochthon) peaks through the overlying crust (allochthon), the structure is considered to be a tectonic window. The parautochthon and the allochthon have different ages, which can be mapped by Neodymium (Nd) isotopes. This project involves detailed mapping of tectonic windows in the Huntsville area of Ontario. Nd isotope analysis was conducted on over 10 rock samples, and crustal formation ages were mapped and analyzed in ArcGIS. The analysis discovered locations where the parautochthon is seen at the surface surrounded by the allochthonous belt. This pattern of windows from the NE to SW supports the proposed synformal folding pattern in the area, giving us a better understanding of the Grenville’s structural history.

Supriya Singh: Evaluating the influence of shrubs on turbulence, energy, and carbon balances in an alpine subarctic environment

Supervisor: Dr. Sean Carey

Due to recent changes in climate, an increase in global temperatures has been observed and is particularly high at northern latitudes affecting the circumpolar region. Surface temperatures have increased by 2°C, which can lead to significant changes to ecosystems, and implications for water, energy, and carbon balances. One of these outcomes due to climate change is increasing vegetation such as the proliferation of shrubs. The objective of this study is to analyse how “shrubbing” influences measures of turbulence, energy, and carbon at Wolf Creek Research Basin in Yukon, Canada. There are two sites of interest within a few kilometres of another: Buckbrush, which has taller shrubs and Plateau, which has shorter shrubs.  Turbulence and flux data from summer 2015 were collected using eddy covariance stations from both sites and were analysed using a combination of Microsoft Excel and Igor Pro. The expected results are that taller shrubs evaporate more water, sequester more carbon, and have a greater frictional velocity compared to shorter shrubs. Radiation balances are projected to be similar at both sites. With a continuously warming climate, this research will contribute to understanding how increased vegetation will affect the water balance, water availability and supply in northern environments.

Kylee Innes: Investigating the Causes and Potential Treatment Options of Sarcopenia

Supervisor: Dr. Stuart Phillips

Human lifespan has increased by 30 years in the last century. As a result, the prevalence of age-related chronic diseases, the frequency of falls and fractures, and the demand for assisted living have increased. Sarcopenia, the age-associated loss of muscle mass and strength, is a major contributing factor to loss of independence. Beginning in the 5th decade of life, muscle mass declines at a rate of ~1% per year and strength at a rate of ~3% per year, greatly reducing physical function.  Although the etiology of sarcopenia is not fully understood, there are several proposed mechanisms. Strategies to slow the decline of muscle mass and strength include resistance exercise and a high quality protein-rich diet. Progressive resistance training (i.e. weightlifting) has been shown to stimulate muscle growth and increase muscle strength, outcomes that are enhanced with consumption of high-quality proteins, such as whey protein. Other dietary supplements, such as creatine, vitamin D, calcium, and omega-3 fatty acids, have been shown to contribute to muscle health. Recently, studies have begun investigating the role of high-intensity interval training in stimulating muscle mass and strength gains.  The aim of this review is to summarize current strategies to counteract sarcopenia in aging. Current research aims to determine if combining multiple strategies could synergistically improve muscle mass, strength, and physical function in elderly people to determine the best therapeutic treatment to counteract sarcopenia. This could reduce prevalence of disability, increase the likelihood of independence, and thus reduce economic pressure on the healthcare system.

ORAL PRESENTATIONS – APRIL 4, 2016

Max Lauch: Efficacy of various testing geometries for measuring waveforms of elastic-liquid interface

Supervisor: Dr. Kari Dalnoki-Veress

Understanding the drag forces of water is fundamental in many aquatic fields, ranging from shipping to professional swimming. With large disturbances, like that of a boat or human, capillary effects are negligible and waves are gravity based. However, at scales smaller than the capillary length of water (the length scale where surface tension become significant at the air-water interface), capillary effects play an essential role. At the sub-millimetre length scale, the effects of surface tension on objects near the water’s surface make the study of water capillary waves and their properties troublesome. This study aims to investigate various methods for measuring wave resistance from a pressure disturbance as small as 10 micrometers. Tests are conducted in a large, rotating channel of water to simulate a moving disturbance, which is created using highly flexible micropipettes stretched to ~10 microns in diameter.  These are excellent force transducers, capable of measuring sub nanonewton forces, allowing measurement of the wave resistance with high precision. Various geometries are employed to minimize the effects of surface tension on the force transducer, circumventing issues that have plagued previous attempts. The results of our study are relevant to the swimming of organisms like whirligig beetles and extend the fundamental understanding of capillary waves and wave resistance to much smaller scales than previously studied.

Michael Wang: Molecular Electronics: Calculating Semi-Empirical Hamiltonians

Supervisor: Dr. Randall Dumont

Molecular electronics is a field of study in which electronic behavior (e.g. current) is examined on the scale of a single molecule. Potential future applications for such systems include molecular-scale circuitry, screens, and even quantum computers. Mobile electrons allow significant molecular conductance, and thus research often focuses on
molecules with π-delocalized systems. In an experimental setup, the molecule of interest is attached to two gold leads. A potential difference across the molecule is then applied at varying levels. The resulting current flow through the molecule can exhibit several interesting characteristics, including rectifying (or diode-like) behavior and light
emission. A source-sink potential, self-consistent Hückel theory model has already been established that models this experimental setup and electronic behavior.

This project’s goal was to elucidate the characteristics of a molecule that allow rectifying behavior. Typical organic diodes localize LUMO to one side of the molecule by using electronegative functional groups, such as amines. This builds a diode wherein one side of the diode is electron-accepting, the other is electron rich. This means that current only easily flows into one side of the molecule. This is typically for a molecule run in the ungrounded mode – a voltage increase on one side is matched by a decrease on the other. In this project, alternative molecules were screened to run in a grounded mode. The theoretical basis for this is poor HOMO or LUMO connectivity to the lead to prevent electrons from entering the molecule. Grounding one side of the molecule and then altering the voltage on the other side can thus still allow or inhibit electron flow.

Stephanie Black: Expression and Characterization of Diacylglycerol Kinase Epsilon (DGKɛ)

Supervisors: Dr. Richard Epand and William Jennings

Diacylglycerol Kinase Epsilon (DGKɛ) is a critical enzyme that catalyzes the formation of phosphatidic acid (PA) through the hydrolysis of diacylglycerol (DAG). The conversion of DAG to PA has a pivotal role within signal transduction pathways, since both species act as secondary messengers and intermediates in the synthesis of several phospholipids, including phosphatidylinositol (PI). DGKɛ is one of ten mammalian isoforms of DGK and is the only isoform known to show specificity for 1-stearoyl-2-arachidonoyl species. The acyl chain specificity of DGKɛ is thought to be connected to epilepsy, cancer, heart and renal disease, among a variety of other disease states. The physiological role of DGKɛ has attracted much research interest, although DGKɛ exhibits a rapid loss of stability in vitro caused by aggregation. DGKɛ ∆40, a variant lacking an N-terminal hydrophobic segment, has the potential to exhibit enhanced stability by mitigating aggregation, while retaining many of the same characteristics as DGKɛ. This project aims to use a Bacculovirus Expression Vector System to transfect insect cells with both DGKɛ and DGKɛ ∆40, overexpress and purify both enzymes, and use circular dichroism spectroscopy to characterize the structural content of DGKɛ ∆40 in comparison with DGKɛ. Preliminary results show successful transfections of insect cells with both enzymes, prior to structural characterization. It is therefore important to thoroughly characterize both DGKɛ and DGKɛ ∆40 in hopes of using DGKɛ ∆40 as a suitable alternative during future laboratory studies to test conformational, enzymatic, and lipid binding properties associated with the function of DGKɛ in vivo.

Mindy Chapman: Effects of the steroidal hormones found in birth control on lipid membranes

Oral contraceptives are commonly used by women in order to prevent pregnancy and treat symptoms, such as acne. Like other pharmaceuticals, birth control pills undergo testing and clinical trials before they are approved and marketed to the public. Consequently, the general side effects of oral contraceptives are quite well documented. However, little is known about how the synthetic steroidal hormones found in birth control interact with human tissue on a smaller scale. Understanding the non-specific interactions of these molecules with human tissue may provide insight into the underlying causes of previously documented side effects, as well as indicating the presence of any other small-scale side effects that have henceforth gone unnoticed

In this study, X-ray diffraction was used to observe the interaction of ethinyl estradiol and norethindrone, hormones found in oral contraceptives, with lipid membranes. Lipid membrane samples with 10mol% norethindrone, 10mol% ethinyl estradiol, and a 10mol% mix of the two were prepared and subsequently scanned using X-ray diffraction. The results will be used to determine the change in structure of the lipid membrane when the hormones found in oral contraceptives are present. This information will provide a better understanding of how oral contraceptives interact with human tissue, and potentially identify either new side effects or underlying causes of known side effects.

Dakota Binkley: Fabrication of polycarolactone electrospun nanofibers doped with silver nanoparticles

Supervisors: Dr. Jose Moran-Mirabal and Dr. Kathryn Grandfield 

Regenerative tissue engineering has yet to significantly improve the functional connection between bone cells and implant surfaces, a concept known as osseointegration. Osseointegration can be inhibited by the presence of bacterial colonies on the implant surface. Polycaprolactone (PCL) coatings have been demonstrated to improve the bioactivity of titanium implants. The emerging nano-technology of silver nanoparticles (NPs) has also exhibited antimicrobial success. In the present study, we intend to demonstrate that optimized electrospun PCL fibers doped with silver NPs have antimicrobial properties. The PCL solution was doped with AgNO3 at various concentrations prior to electrospinning and once fibers were produced, the mats were subjected to air plasma treatment for 1, 5, 10, and 30 minutes. The samples were imaged using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Images were further analyzed using ImageJ software. SEM imaging demonstrated continuous fibers at all AgNO3 concentrations. Air plasma treatment resulted in a decrease of fiber diameter with increasing plasma times; however, all samples subjected to 30 minutes of air plasma treatment were completely etched. Current results suggest ample particle nucleation on fiber surfaces, which strengthens the probability of the material exhibiting antimicrobial properties. Samples will be tested against Staphylococcus aureus and if bactericidal activity is observed, the scaffold material can be used to coat titanium implants and ultimately decrease implant failure rates associated with host bacterial infections.

Jaime Knoch: Immunosuppression of 3xTg AD mice and its effect on learning and memory, behaviour, and pathophysiology

Evidence of increased activation of proinflammatory immune pathways has been demonstrated in previous research with transgenic mice models of Alzheimer’s disease, as well as many post-mortem studies of human Alzheimer’s patients. However, this research does not establish whether this immune system involvement is the driving force of the pathology seen in Alzheimer’s disease (AD) or a protective response. Furthermore, none of these studies have included sex as an experimental factor, despite sex hormones’ known effects on immunopathology and neuropathology. In this study, we plan to elucidate the link between Alzheimer’s and the immune system by removing the immune system as a factor in the progression of the disease. We do this by examining the effects of immunosuppression on wild type (WT) and triple-transgenic AD (3xTg AD) mice of both sexes. We use a solution of cyclophosphamide, an immunosuppressive agent, to eradicate the immune system in half of the mice, while the other half receive sucrose solution. Once the immune system is eradicated, we will study the change in behaviour, learning and memory through a behavioural battery. We hypothesize that when the mice are immunosuppressed the symptoms and pathophysiology of Alzheimer’s will be alleviated, and that there will be sex differences in the effect of this treatment. We expect to see improvement in learning and memory tests, and emotional reactivity tests from the immunosuppressed AD mice, as well as reduced evidence of pathophysiology post-mortem.

Julianna Stangroom: The Impact of Soil Sulfur on Glucosinolate Content of Eutrema salsugineum

Supervisor: Dr. Elizabeth Weretilnyk 

Glucosinolates are sulfur-rich defense compounds with anti-herbivory properties found in Eutrema salsugineum. Glucosinolate-containing plants tend to have high sulfur requirements thought to be due to glucosinolate production. The aim of this study is to determine whether high soil-sulfur promotes glucosinolate accumulation in Eutrema leaves and to develop a reliable method of quantifying glucosinolate content.

Extracts were prepared from leaves were quantified by a spectrophotometric method relying on the oxidation of ferricyanide to form a colourless byproduct. Yukon ecotype Eutrema plants were grown in sulfur-rich or sulfur-limiting (control) conditions. Leaves were freeze-dried and ground in water, extracts were cleared by centrifugation and the supernatant divided into aliquots.  One-half of the supernatant was incubated at 30°C to allow endogenous myrosinase to hydrolyse glucosinolates to 1-thioglucose, the component detected by ferricyanide oxidation.  The remainder of the supernatant was treated to deactivate myrosinase to account for background oxidation of ferricyanide by other components in the leaf extract.  Following passage through a DEAE-Sephadex anion exchange matrix, the ferricyanide-based assay was performed and compared to a standard curve generated using a commercially available glucosinolate (sinigrin).

Myrosinase-dependent oxidation of ferricyanide was detected indicating the presence of glucosinolates in Eutrema leaves. With a protocol in place, leaves of plants grown in sulfur-rich and control conditions will be assayed for glucosinolate content. Whether or not soil-sulfur can influence glucosinolate accumulation by plants is of agricultural interest for the protection of plants from herbivory.

Alex Dhaliwal: Red Blood Cell Ghosts for Biomedical Applications

Supervisors: Dr. Sebastian Himbert and Dr. Maikel Rheinstädter

While artificial supported bilayers have provided a wealth of information regarding the structure and dynamics of cellular membranes, the extent to which these results can be applied to living systems is limited. The use of red blood cells that have been extracted, lysed, sonicated, and stacked onto a solid substrate offers a new avenue for exploring biological membrane phenomena, as they provide a more realistic model while remaining examinable through the same physical techniques. One question that could be investigated using this system is the mechanism of action of ß-hemolysin/cytolysin, a toxin produced by Streptococcus agalactiae and other members of a family of bacteria known as Group B Streptococci or GBS 1,2. These microorganisms are the primary cause of neonatal infection in North America, affecting thousands every year 3.

In this experiment, preliminary trials are being conducted using stacks of red blood cell ghosts mounted on silicon wafers. The structural characteristics of the stacked membranes will be examined using X-ray diffraction both before inoculation with the bacteria and after exposure. Various techniques for exposing the samples to the bacteria will be attempted, alongside several controls. Positive controls will use various concentrations of Triton X-100, and negative controls will use ddH2O. Comparisons between the X-ray diffraction data will be made to determine if characteristic destruction of bilayer morphology will allow for the correlation of certain patterns to specific toxins. This simple system can have important clinical implications, as it would provide a new way to identify GBS in patients and increase the efficacy of preventative measures, such as intrapartum antibiotic prophylaxis4.

References:

Liu, G.Y. & Nizet, V., 2005. Toxins Acting On The Surface of Target Cells (Except Superantigens). InThe Comprehensive Sourcebook of Bacterial Protein Toxins. pp. 735–745.

Marchlewicz, B.A. & Duncan, J.L., 1981. Lysis of erythrocytes by a hemolysin produced by a group B Streptococcus sp. Infect. Immun., 34(3), pp.787–794. Available at: http://iai.asm.org/content/34/3/787.short [Accessed February 1, 2016].

Edwards MS, Nizet V, Baker CJ. Group B streptococcal infections. In: Remington JS, Klein JO, Wilson CB, Nizet V, Maldonado UA, editors. Infectious diseases of the fetus and newborn infant. 7th ed. Philadelphia, PA: Elsevier; 2011. pp. 419–69.

Nizet, V., 2002. Streptococcal β-hemolysins: genetics and role in disease pathogenesis. Trends in Microbiology, 10(12), pp.575–580. Available at: http://www.sciencedirect.com/science/article/pii/S0966842X02024733 [Accessed October 31, 2015].

POSTER PRESENTATIONS – APRIL 7, 2016

Miriam Krzyzewska: Analyzing Psychiatric Comorbidity in Non-celiac Gluten Sensitivity: A Murine Model of Gliadin Sensitization on Behaviour & Gut Function

Supervisors: Dr. Premysl Bercik, Marc Pigrau

Non-celiac gluten sensitivity (NCGS) is an increasingly prevalent disorder. NCGS is defined as a group of gastrointestinal and psychiatric manifestations precipitated by gluten ingestion after the exclusion of celiac disease and wheat allergy. Although diagnostic biomarkers have yet to be identified, approximately 50% of patients with NCGS express celiac susceptibility genes and anti-gliadin antibodies. NCGS patients carry a significant burden of comorbidity including psychiatric dysfunctions triggered by an immune reaction to gluten. We aim to investigate the effect of gliadin sensitization and challenge on behaviour and motility in mice expressing the human HLA-DQ8 gene, and wild type mice. Behaviour was evaluated by the step-down, light preference, tail suspension, and sucrose tests while motility was assessed by bead videofluoroscopy. It is predicted that gliadin sensitization and challenge will induce anxiety-like behaviour, as well as hinder motility in NOD-DQ8 mice. No adverse effects are expected to be seen in wild type mice. We propose that the fundamental problem may be a result of microbiota dysbiosis, nutritional deficiency, or gluten’s interference with the body’s neural networks. The heterogeneous nature of this disease and the accumulating evidence of diverse manifestations such as psychiatric comorbidity urges a re-evaluation of the belief that gluten sensitivity is solely a disease of the gut. Such studies have the potential to increase our understanding of a broad spectrum of human disease, and to generate novel therapies for these conditions based on the identification of mechanisms underlying NCGS.

Angelico Obille: Investigating methods of functionalizing cellulosic materials

Supervisor Name: Dr. Jose Moran-Mirabal

Cellulose is a naturally produced biodegradable polymer of glucose with high structural integrity. As an abundant resource, ongoing research seeks to create cellulose-derived composites that can effectively replace non-biodegradable materials. Methods of functionalizing cellulose in the forms of cellulose nanocrystals and paper to alter its properties are investigated. To date, cellulose has been modified with various moieties such as poly-ethylene glycol, benzene, and allylamine. Of particular interest is allylamine functionalization because the exploitation of the double bond allows for a wide range of applications in modifying cellulosic materials. Specifically, the reaction between thiols and allylamine, namely thiol-ene reactions, allows for the ability of these thiols and their accompanying chemical and mechanical properties to be “clicked” onto the cellulosic material. Octadecanethiol, a hydrophobic thiol and mercaptohexanol, a hydrophilic thiol, are two thiols that have been shown to be clicked onto the allylamine-treated cellulosic materials. Various characterization techniques are performed to verify the results of this project. To verify the successful synthesis of the allylamine derivative that is to be added onto cellulose, nuclear magnetic resonance spectroscopy and mass spectrometry are performed. The products are integrated onto paper in which the thiol-ene click chemistry is then employed. To prove that cellulosic modification has been successful, contact angle measurements reflect that the clicking of octadecanethiol increases the hydrophobicity of the paper and that the clicking of mercaptohexanol increases its hydrophilicity. The results of this project show promise in the use of thiol-ene click chemistry to modify cellulose with a wide range of applications.