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Chemical protein engineering of elastin-like polypeptides (ELPs) as a potential bioadhesive scaffold
No full textBioadhesives are essential for tissue adhesion and regeneration. Optimal bioadhesive should possess elasticity, robust adhesion capabilities in wet environments, and a cytocompatible scaffold for cell regeneration. Current options like cyanoacrylates and fibrin glues fail in these aspects due to cell toxicity and poor moisture adhesion, prompting the need for new materials that reconcile cytocompatibility with robust adhesion. These limitations by available commercial bioadhesives, demand the development of new adhesive biomaterials that combine cytocompatibility with strong adhesion.
Marine organisms such as mussels secrete proteins that adhere effectively even underwater, but the adhesion mechanisms remain partly elusive. These proteins' adhesion strength is largely attributed to catechol side chains of L-Dopa, which can form various surface interactions, including hydrogen bonding and metal coordination. Commercial use of natural adhesive proteins is time- and labor-demanding, and uneconomical, as it takes thousands of mussel specimens to extract just one gram of adhesive proteins. In addition, low expression yield, low purification yield, and high levels of post-purification insolubility, restrict the production of recombinant foot protein types in Escherichia coli.
To overcome these issues and inspired by intrinsically disordered domains of tropoelastin, the soluble precursor of elastin, elastin-like polypeptides (ELPs) consist of repeated sequences of the pentapeptide motif “VPGXG” (with “X” representing any amino acids except proline), emerge as promising synthetic alternatives. These stimuli-responsive adhesives exhibit a reversible phase transition regulated by temperature, making them suitable for applications such as drug delivery and wound healing. Their lower critical solution temperature (LCST) can be genetically adjusted to just below human body temperature, offering versatility for medical use.
The bioadhesive efficacy of ELPs is linked to Dopa, crucial for adhesion, which is prone to unwanted oxidation during protein synthesis and purification. To counter this, we use a Dopa analog, meta-(ortho-(2-nitrobenzyl))-3,4-dihydroxyphenylalanine (m-oNB-Dopa), which is photocleavable and allows precise control over adhesion processes upon light irradiation.
As a first step to achieving this goal, we designed two different constructs of ELP protein; one as a wild-type model protein containing tyrosine, valine, and lysine, as the “X” guest residues, and the other ELP construct containing amber stop codons replaced by tyrosine codons, was used to expand the scope of protein constructs.February 202
Field, textural, and geochronological investigations into the intrusion dynamics and crystallization histories of the Separation Rapids rare-metal pegmatites, northwestern Ontario
No full textThe Separation Lake greenstone belt (SLgb) is host to a suite of potentially economic Neoarchean Lithium – Cesium – Tantalum (LCT) complex type, petalite subtype granitic pegmatites (Big Whopper, Big Mack, Snowbank, Glitter and Marko’s). Field observations on these pegmatites such as well-developed layering, ptygmatic folds, boudins, and mullions have in the past led investigators to infer that the pegmatites experienced pervasive high-strain deformation after emplacement.
In this study, we reinterpret the field relations between the pegmatites and country rock, incorporate pegmatite microtextures, and date, by the U-Pb method, the time of crystallization to reassess the role of regional-scale deformation in the distribution and morphology of these pegmatites. Uranium-Pb ratios in monazite and titanite were measured, in-situ, by LA-ICP-MS to establish the timing of regional metamorphism and pegmatite intrusion. Monazite in the country rock yields the same age, within error, of the ca. 2650 Ma Separation Rapids pluton and suggests intrusion and metamorphism were coeval in the area. The range of monazite U-Pb ages of ca. 2637 Ma, ca. 2617 Ma, and ca. 2602 Ma indicate that the pegmatites crystallized after metamorphism / deformation and may not be related to one magmatic event.
Field relationships and microtextural data indicate that deformation is induced locally (i.e., not regional) and results from emplacement mechanisms during pegmatite intrusion. The dominant fabric in the country rock is defined by the alignment of hornblende and is cut by the pegmatite. Moreover, all pegmatites have a metasomatic halo of biotite that overprints the S2 fabric in the country rock. Essentially, the pegmatites acted as viscous indenters into fluidized, weakened, ductile country rock. Recognizing the fact that deformation is not a result of regional-scale deformation has important implications for exploration including: 1) pegmatites need not intrude along structural corridors, 2) the dominant direction of propagation is now oriented subvertical with the surface expression of several pegmatites suggesting the bulk of the intrusions lies buried under the current erosional surface; and 3) undiscovered LCT pegmatites may lie within other segments of metavolcanic rocks along the English River – Winnipeg River subprovincial boundary, as similar emplacement ages across the SLgb and Bird River belt of eastern Manitoba (e.g. Big Mack at ca. 2637 Ma and Tanco at ca. 2640 Ma) may infer continuous mineralization along the boundary.Avalon Advanced Materials
University of ManitobaOctober 202
Understanding the impact of the levels of alpha-amylase on wheat flour functionality and breadmaking
No full textWheat is crucial for the global food supply, but climate change and unpredictable weather conditions, like heavy rainfalls, strain the wheat supply chain due to germination. Wheat germination affects flour’s bread-making quality, yet understanding its impact is limited. This research aims to assess the physicochemical changes that occur in wheat during germination by evaluating the flour breadmaking functionality and the resulting bread characteristics. Wheat kernels belonging to class Canada Western Red Spring (CWRS) were germinated at 21°C for up to 36 hours (0 h, 6 h, 12 h, 18 h, 24 h, and 36 h, which were coded as G0, G6, G12, G18, G24 and G36, respectively) to trigger different levels enzyme activities. Morpho-geometric features showed a progressive increase along germination time, particularly after 18 hours of germination. The falling number (FN) value decreased from 385 seconds in the sound wheat to 63 seconds in G36, while alpha-amylase activity in those samples was 0.11 CU/g and 6.96 CU/g, respectively. Pasting parameters showed a significant decrease after 12 hours of germination. The apparent peak viscosity of sound wheat (1192 mPa.s) was negligible in G36 (85 mPa.s). The apparent viscosity was recovered by adding silver nitrate 1 mM, although silver nitrate 10 mM was needed to inhibit the alpha-amylase activity in G24 and G36. The thermal properties of the control flour showed higher enthalpy values (4.86 J/g). Germination affected gluten functionality as indicated by the gluten performance index (GPI) decrease at G24 (0.40) and G36 (0.39) and the mixing properties like mixing tolerance index (133, 134, respectively), reflecting decreased gluten strength. A modified method for assessing gluten index suggested that despite gluten degradation after 24 h and 36 h of germination, proteins were able to aggregate after 120 min resting. Further, mini-breads displayed increased 2D area in G24 and G36 and lower crumb hardness in G24 and G36. Despite gluten degradation, proteins aggregate sufficiently for bread leavening results an enhanced mini-breads area. Mini breads made from germinated flour show promise for human consumption. Overall, this approach could help produce green-label products and reduce losses from sprouting, promoting sustainability in the food industry.University Research Grants Program (URGP), University of ManitobaOctober 202
Earth Sciences Graduate Symposium Program with Abstracts
No full textAbstract book for the Earth Sciences Graduate Symposiu
Simulation of proton in silicon using GEANT4 for Beam Lifetime 3 experiment
No full textThe Beam Lifetime 3 (BL3) experiment at the National Institute of Standards and Technology, USA, aims to improve the precision of neutron lifetime measurements and will hopefully resolve the inconsistency between beam and bottle measurements of the neutron lifetime by enhancing the precision of this beam measurement. In the BL3 experiment, where protons from neutron decay are detected in a silicon detector, a GEANT4-based simulation was used to model, develop, and optimize the experimental setup. The physics list, used to simulate particle transportation and interactions, was derived from one of the advanced examples of GEANT4 and extended with a screened nuclear recoil model appropriate for low-energy proton-nucleus scattering of protons in silicon. This approach will allow the many applications of the SRIM (Stopping and Range of Ions in Matter) software for modelling these interactions to be expanded into the much more general GEANT4 framework where nuclear and other effects can be included. By using the example in TestEm7/StandardNR, G4BL3/SNR, and the physics list in GEANT4, the energy deposition and backscattering/ transmission of 35 keV protons on a silicon detector are studied. Comparing the outcomes with SRIM and confirming the energy accumulation in GEANT4's numerous processes and its effects on the ratio of various components are being analyzed.May 202
Effects of plant species composition and nutrient addition ratio on the efficacy of bioremediation of simulated freshwater oil spills by engineered floating wetlands
No full textThe transportation of crude oil across Canada leads to a risk of accidental spills into freshwater environments. Conventional cleanup methods can exacerbate the negative effects of oil spills and delay ecosystem recovery. A less-invasive alternative is the use of engineered floating wetlands (EFWs) – vegetated platforms which promote microbial colonization and biofilm formation in their underwater root-zones – to enhance the biodegradation of spilled oil. This thesis assessed the efficacy of EFWs for removing oil-derived polycyclic aromatic compounds (PACs) from fresh water and the effects of plant species composition and nutrient addition carbon to phosphorus (C:P) ratio on EFW function. Twenty-six (26) ~1550 L mesocosms containing EFWs were exposed to equal-volume spills of water-accommodated fraction (WAF) produced by weathering conventional heavy crude oil (CHV). The EFWs were either planted with a different composition of Typha sp., Carex atherodes, and C. lasiocarpa or had an even species composition and were amended with slow-release fertilizer to achieve a target C:P ratio, based on the carbon content of the WAF. Concentrations of PACs decreased rapidly, with 96.8% of compound classes across the mesocosms declining to baseline concentrations within the first 10 days of the 96-day exposure. There was no evidence to indicate that EFWs had an appreciable effect on PAC removal or that changes in plant species composition or C:P ratio affected EFW function. There were no consistent significant effects of WAF, plant presence, plant species, or C:P ratio on the activity of microbial biofilm or the composition and diversity of the prokaryotic and eukaryotic microbial communities in the root-zone. Results were confounded by low initial PAC concentrations, possibility of PAC sorption to mesocosm plastic, flaws in sample event timing, and tadpole grazing on root biofilm; future research which addresses these experimental limitations is required to support the incorporation of EFWs into freshwater oil spill remediation efforts.October 202
Intimate partner violence, precarious immigration status and migration through the lens of international human rights law: a policy review of Canada and the United Kingdom
No full textInternationally, human rights obligations pertaining to the protection of women from experiencing Intimate Partner Violence (IPV) in addition to the eradication of IPV continues to be ignored and further violated by states. This has a unique impact on those experiencing IPV who also exist at the axes of inequality, including migrants. The interplay between migration and victims of IPV is nuanced. One which is largely mutually exclusive, where legal systems that seek to protect migrants or seek protect women facing gender-based violence may not account for the experience of those requiring protection in both realms. The consequences for victims with insecure or precarious immigration status (this includes those who may be undocumented, on a spouse sponsored Visa, refugee claimants, humanitarian and compassionate ground applicants, visitors and students) culminate in numerous uncertainties and barriers including access to securing safety, access to support services, housing, health care and other forms of social assistance. These barriers are all compounded by pressures from immigration and other legal systems, to which survivors may begin to fear removal, deportation or destitution, in many cases leaving the victim to make the decision to stay with their abuser, in order to avoid persecution. As the policing of migration continues to rise on an international level; status is continuing to supersede safety as women with precarious immigration status that are victims of IPV are excluded from many avenues of support. This paper comparatively explores the domestic policies in place for victims of IPV that have precarious or insecure immigration status, across two jurisdictions, the UK and Canada. This paper will also critically engage with the obligations that both states have under international human rights law, including a specific focus on The Council of Europe Convention on Preventing and Combating Violence against Women and Domestic Violence (The Istanbul Convention).May 202
The studies of extracellular matrix proteins and their role in protein production, inhibition, and regulation using hybrid structural-biophysical approaches
No full textThe extracellular matrix (ECM) is a dynamic and intricate environment crucial for cellular function and tissue homeostasis. Within this milieu, our investigation focuses on critical proteins, Netrin-4 and Central Communication Network 2 (CCN2), and their role in regulating ECM rearrangement and stability. Employing kinetic, biophysical, and structural methodologies, including x-ray crystallography, analytical ultracentrifugation (AUC), and biolayer interferometry, we study the structural features, hydrodynamics, and affinities of key protein complexes in solution. Our findings reveal that Netrin-4 influences the ECM environment by disrupting the pre-existing ternary laminin node complex. This disruption occurs through the inhibition of the initial heterodimerization of laminin γ1/β1, forming high-affinity Netrin-4/laminin γ1 complex. As an important ECM component, laminin polymerization disruption negatively affects cellular migration across laminin-rich environments.
Our study of CCN2 investigated the therapeutic mechanism of anti-CCN2 Fab fragment 37-45-MH1. Anti-CCN2 Fab 37-45-MH1 demonstrated the efficacy in fibrotic presentations and blocking the binding domains of transforming growth factor-beta 1 (TGF-β1), bone morphogenetic protein 2 (BMP2), and BMP4. This thesis shows 37-45-MH1 specifically targeting the van Willebrand factor type C (vWc) domain by preventing conformational rearrangement. Notably, targeting the CCN2 vWc domain does not interfere with CCN2 binding via heparin to BMP2. Lastly, we present the development of a multiwavelength-AUC binding assay to study protein-protein interactions, focusing on Netrin-1/Uncoordinated 5 (NET1/UNC5) complex formation. This assay allowed for the simultaneous measurement of UNC5 in complex with both monomeric and dimeric forms of NET1. The assays were done by labeling UNC5 with an alexa488 fluorophore, then deconvoluting and separating labelled-UNC5 signal from NET1/UNC5 samples.February 202
Restoring Manoomin in Brokenhead Ojibway Nation through a community-led approach: implications on food security and the local economy
No full textManoomin (Zizania palustris), also known as wild rice, is a culturally, spiritually, nutritionally, and ecologically important plant to the Ojibway people. Production and management of Manoomin are deeply rooted in Indigenous food system knowledge (IFSK), which was negatively affected by colonial legacies. This research asked whether Manoomin production can play a significant role in the Ojibway economy amid high food insecurity, structural barriers to traditional food access, and challenges to sustainable livelihoods. My mixed methodology research employed the need-based approach (NBA) in investigating a sustainable pathway to restoring Manoomin to Brokenhead Ojibway Nations (BON). Community members enrolled in the Kitigay pilot program, a project-based post-secondary education program, took the lead in restoring Manoomin in BON and transforming the abandoned weedy Bison Ranch farm for gardening and orchard planting. An initial 60 pounds of Manoomin was procured and planted in BON Rivers in October 2024, with community members' active participation. Later, a community café was organized in collaboration with community members. The community café’s impact resulted in the BON Chief and Council purchasing and planting an additional 2,000 pounds of Manoomin in 2023, applying IFSK.
A community café, survey, and participatory action research undertaken in this study indicate that Manoomin is regarded as an essential component of the Ojibway people’s food chain, economy, and environment. Eighty-one percent of the 21 participants who completed the semi-structured survey indicated the likelihood of participating in future community-led Manoomin restoration projects. In ranked order (1 = not at all important to 5 = very important), the three most compelling reasons among ten variables for participating in the community café are transferring IFSK to the youth (90%), reviving IFSK (88%), and income and employment opportunities (86%). The Spearman’s correlation results suggest a strong positive correlation between reviving IFSK and transferring IFK to the youth (r =.67, n = 21, p < .001). A strong positive correlation exists between reviving IFSK and decolonizing IFSK (r =.57, n = 21, p < .007). The Manoomin restoration in BON presents a compelling argument for community-led participatory approaches to addressing food insecurity problems in Indigenous communities.February 202
A Literature Review: Barriers to Care Amongst Immigrant Women with Postpartum Depression in Canada
No full textIntroduction:
Postpartum depression (PPD) is a prevalent condition among new mothers, affecting 10-15% of the population. However, immigrant women are at a higher risk of developing PPD than non-immigrant women, with a 1.5-5 times greater likelihood. Access barriers such as social isolation, financial instability, and limited awareness of healthcare services hinder PPD care access for immigrant women. Although the Canadian Task Force Prevention Guidelines advocate for PPD screening, a lack of substantial research on its importance could potentially increase the challenges immigrant women encounter when seeking proper PPD care.
Objective:
For this literature review, several online databases were utilized. This review aims to identify the barriers immigrant women face when seeking help for postpartum depression and understand what would help meet the mental health needs of immigrant and refugee women during the postpartum period.
Methods:
Using key terms related to access barriers to postpartum depression care among immigrant women in Canada. This review searched several online databases, including PubMed, Scopus, and CINAHL. Six articles met the inclusion criteria and were analyzed.
Results:
Five studies explored the challenges immigrant women experience when seeking postpartum depression care in Canada, while one study investigated Canadian guidelines on the recommendation against screening for postpartum depression. However, only limited insight was given into its effects on the immigrant population. Three common themes that affected immigrant women's behaviour when seeking care were a cultural influence on PPD, lack of awareness about service accessibility and quality of care, and migrant-related issues such as language barriers and discrimination.
Conclusion:
This literature review highlights the multifaceted nature of the challenges faced by immigrant women in accessing postpartum care for depression in Canada. Factors such as language barriers, stigma, cultural influence on help-seeking behaviours, lack of awareness about available services, and migrant-related issues contribute to these challenges. The study underscores the need for culturally sensitive care that considers the unique experiences of immigrant women. Additionally, the findings highlight the importance of training healthcare professionals to improve their cultural understanding and awareness, which can help build trusting relationships with their patients. This review provides practical recommendations for improving care delivery and outcomes, including greater awareness about available services and incorporating PPD screening into Canadian guidelines