Browsing by Author "Benoit, Wendy L."

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    Gout Biosensor: Towards the development of a peptide-based diagnostic for crystal arthropathies and Amplifying Graduate Student Perspectives on Supervision and Satisfaction at the University of Calgary
    (2024-09-19) Butler, Tanille Marya; MacCallum, Justin L.; Derksen, Darren J.; Sutherland, Todd C.; Benoit, Wendy L.; Derda, Ratmir
    This thesis primarily investigates the use of fluorescently labelled crystal-targeting peptides to develop a gout biosensor to improve the diagnostics of crystal arthropathies. Additionally, Chapter 7 examines survey responses from a secondary research project exploring graduate student experiences related to supervision and satisfaction within NSERC disciplines at the University of Calgary. With the growing prevalence of gout, there is an increasing need for accurate, cost-effective, and automated diagnostic methods to distinguish between monosodium urate (MSU) crystals, which cause gout, and calcium pyrophosphate dihydrate (CPPD) crystals, responsible for pseudogout. The current gold-standard diagnostic approach, compensated polarized light microscopy, is limited by its dependence on operator skill and lack of automation. To address these challenges, the study employed a multifaceted strategy involving phage display, peptide synthesis, microscopy, flow cytometry, and computational modelling to identify peptides capable of differentiating between MSU and CPPD crystals. Initial phage display efforts were hindered by high background binding of the phage, leading to the unexpected discovery of an interaction between MSU crystals and the major coat protein of the bacteriophage. This finding laid the groundwork for enhancing peptide binding to MSU crystals. While the identified peptides demonstrated strong binding to MSU crystals, specificity remained a challenge due to similar binding observed with CPPD crystals. An Alizarin Red S counterstain was introduced to improve differentiation, distinguishing CPPD crystals without affecting MSU crystals in microscopy studies. However, when flow cytometry was explored as a high-throughput tool, we encountered challenges with dye compatibility. Although 84% accuracy was achieved in classifying individual crystals through logistic regression of peptide-bound crystal data, issues with dye stability and clinical sample complexity indicate further refinement is needed before clinical implementation. The second project focused on graduate students' supervisory and program experiences in NSERC disciplines at the University of Calgary. Data from the 2022 and 2023 Graduate Student Experience Surveys indicated overall satisfaction with supervisory support and communication but highlighted ongoing issues with inadequate funding and mental health challenges despite available institutional resources. These findings highlight areas where enhanced supervisor support and training could better meet evolving student needs.
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    Syntheses and resolutions of heterobifunctionalized p-stereogenic phosphines: applications as substrate-bound chiral auxiliaries and ligands in asymmetric reactions
    (2007) Benoit, Wendy L.; Keay, Brian A.
    P-stereogenic phosphine ligands play an important role m the development of new and effective asymmetric catalysts. A review of the recent literature revealed that P­stereogenic phosphines are challenging synthetic targets, as they do not occur naturally and must therefore be made through asymmetric synthesis. Plans were then devised to test a camphor-derived chiral auxiliary and a spiro-1 ,3-arnino alcohol auxiliary for the asymmetric synthesis of P-stereogenic phosphines for use as ligands in asymmetric catalysis Camphor-derived organoazide [2-(tert-butyl-dirnethyl-si lanyloxy )-7, 7-di??ethyl­bicyclo[2.2. l ]hept- l-yl]-methanesulfony l azide was attached to a heterobifunctionalized racemic P-stereogenic oxazaphospholidine to give a 1: 1 mixture of diastereomeric phosphinimines that were separated by chromatographic methods. The absolute configuration of each phosphorus center was determined by X-ray crystallography. Efforts to remove the chiral auxiliary were unsuccessful. Thus, the introduction of different functional groups at phosphorus were carried out with the auxiliary attached with up to 77% yield of ring-opened product. However, the tedious chromatography and troublesome later steps forced abandonment of the approach in pursuit of more practical methods. A derivative of spiro 1,3-amino alcohol ( 5R,6R)-6-amino-spiro[ 4.4 ]nonan-1-ol was used as a chiral auxiliary to form a heterobifunctionalized P-stereogenic oxazaphosphorinane in a 2.5: 1 mixture of diastereomers. The major diastereomer was isolated from the mixture via recrystallization in a 36% yield and its absolute stereochemistry was found to be Rp by X-ray crystallography. (SR, 6aR, 9aR)-6-Methyl-5-phenyl-decahydro-4-oxa-6-aza-5-phospha-cyclopenta[ d]indene borane was then reacted with various nucleophiles in efforts to develop a general route to P-stereogenic phosphines. The nucleophilic oxazaphosphorinane ring openings were perfom1ed in up to 77% yield, but unfortunately gave a 50:50 mixture of diastereomeric products. The lack of stereoselectivity prompted efforts to be directed toward using deprotected (SR, 6aR, 9aR)-6-methyl-5-phenyl-decahydro-4-oxa-6-aza-5-phospha-cyclopenta[ d]indene borane as a P-stereogenic catalyst precursor. After failed attempts at using (SR, 6aR, 9aR)-6-methyl-5-phenyl-decahydro-4- oxa-6-aza-5-phospha-cyclopenta[ d]indene borane as a P-stereogenic organocatalyst, conditions were developed to remove the borane protecting group and use (SR, 6aR, 9aR)-6-methyl-5-phenyl-decahydro-4-oxa-6-aza-5-phospha-cyclopenta[ d]indene as a P­stereogenic ligand for transition metal catalysis. Poor results from this led to the synthesis of a chelating spiro oxazaphosphorinane derivative. Rhodium-catalyzed hydrogenation of methyl 2-acetamidoacrylate usmg the dimerized sp1ro oxazaphosphinane ligand was performed with up to 15% ee. Extreme sensitivity of the oxazaphosphinane ligands toward oxidation prevented further optimization of the enantioselectivity.
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    Using Formative Assessments to Inform Course Goals
    (Taylor Institute Teaching Community, 2014-05-13) Benoit, Wendy L.