About MacSphere

MacSphere is McMaster University's Institutional Repository. MacSphere brings together the institution's scholarly works under one umbrella to preserve and provide ongoing open access to them. MacSphere works have been selected and deposited by members of the McMaster community as part of our collective committment to sharing our knowledge with the world.

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Recent Submissions

RISE brief 1: OHT building blocks
(2019-08) Lavis JN
Key insights to support Ontario Health Teams in their work related to OHT building blocks.
Ecclesial Unity and Implications for Societal Transformation and Harmony in Nigeria
(2026) Boluwatise, Isaac A. Tolu; Payton Jr., James R.; Wen, Clement; Christian Studies
This study examines Johannine ecclesiology as a theological framework for addressing persistent ethnoreligious divisions in Nigeria. While the Nigerian church has often mirrored societal fractures through tribalism, denominational rivalry, and politicized religion, the Gospel of John presents unity as both ontological and missional. In John 13 and 17, Jesus grounds discipleship in mutual love and prays for visible oneness “so that the world may believe.” Engaging Johannine scholarship from Bauckham, Byers, Gorman, and Ferreira alongside African voices such as Tarus, Katongole, and Mugambi, the study develops a constructive theological account of unity as both a divine gift and public responsibility. It situates the Nigerian context within a broader African theological conversation on ecclesial unity. The thesis argues that when grounded in the theological vision of unity and love articulated in John’s Gospel, the Nigerian church can embody Christ’s prayer and serve as a credible agent of societal reconciliation and transformation.
Action, Evidence, and Empathy When It Feels Like “There Is No More To Give”: Moral Experiences of Healthcare Workers and Researchers in Humanitarian and Public Health Crises
(2026) Yantzi, Rachel Marie; Schwartz, Lisa; Health Research Methodology
When responding to public health crises such as the COVID-19 pandemic or caring for children with palliative care needs in complex humanitarian crises, healthcare workers may feel powerless or uncertain as to how they should act in response to the overwhelming needs of patients and communities. This dissertation aims to better understand the moral experiences of health and health research personnel during humanitarian and public health crises, taking seriously their moral experiences as windows into the ethical dimensions of these contexts, and to explore how understanding their moral experiences may be useful in improving care and ethical practice. Firstly, an interview-based interpretive description study examines the moral experiences of health and health research personnel who worked at the intersection of research and clinical care during the first wave of the COVID-19 pandemic. Secondly, a focused ethnographic study conducted at an Médecins Sans Frontières pediatric hospital in Cox’s Bazar, Bangladesh explores health care workers moral experiences related to palliative and end of life care in a humanitarian crisis context. A narrative exploration of the ethnographic findings is presented using composite stories focused on the value and challenges to empathy in humanitarian action. Finally, a reflexive analysis explores my moral experience of the research process including implications of my identity as a practicing nurse, multiple roles in the research context, and relationships with research participants. While the two studies were conducted in very different crisis contexts, the overall dissertation demonstrates the importance of evidence-based practice as a reference point that shapes the moral experience of health care workers in crisis contexts. The dissertation contributes to understanding the implications of healthcare workers moral compulsion to act on behalf of their patients, and the value of broader understandings of action in crisis contexts where the evidence-base is often inadequate.
Identifying Colonization Resistance Activities of the Commensal Upper Respiratory Tract Microbiota
(2026) ElChaar, Nancy; Surette, Michael; Bowdish, Dawn; Medical Sciences
Background: The upper respiratory tract (URT) microbiome contributes to colonization resistance against respiratory pathogens such as Streptococcus pneumoniae, a causative agent of pneumonia. Bacterial pneumonia often begins with pathogen colonization in the URT before spreading to the lower airways. The resident microbiota serves as a first line of defense by competing for nutrients and space, as well as by producing antimicrobial compounds. We hypothesize that these microbiota-derived antimicrobial molecules can suppress pneumococcal growth and colonization. This study aimed to identify and characterize URT commensal bacteria with anti-S. pneumoniae activity and define bioactive products. Methods: A collection of nasal commensals from healthy adults was cultured and screened for antimicrobial activity against S. pneumoniae using agar-based inhibition assays. Active strains underwent activity-guided purification, liquid chromatography-mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR) spectroscopy for structural elucidation of the bioactive molecule. Whole-genome analysis and comparative genomics were performed to identify relevant biosynthetic gene clusters (BGCs). Results: Over 2,000 bacterial isolates representing diverse URT taxa were assembled, and 48 strains from various genera exhibited anti-pneumococcal activity. Micrococcus luteus GC1842 showed potent inhibition of S. pneumoniae. The produced bioactive metabolites were identified as geninthiocin-family molecules, encoded by a unique thiopeptide BGC. These compounds inhibited S. pneumoniae with limited activity against other respiratory bacteria, suggesting a targeted mechanism which may contribute to minimizing microbiota disruption. Conclusions: We identify a human-associated M. luteus strain that produces a geninthiocin-like thiopeptide active against S. pneumoniae. Overall, findings demonstrate that colonization resistance in the URT is mediated by diverse commensal bacteria and distinct mechanisms, including thiopeptide antibiotics. We identify novel mechanisms of competition in the URT and expand the ecological and chemical scope of nasal commensals, prioritizing isolates with the potential to be developed into probiotics or postbiotic strategies that reinforce colonization resistance to prevent pneumococcal disease.
Defining a minimal symbiotic genome of the legume symbiont Sinorhizobium meliloti
(2026) Kearsley, Jason Vincent Shields; Finan, Turlough; Biology
Identifying and understanding bacterial genes involved in the formation of N2-fixing root nodules is of agricultural and environmental interest. Sinorhizobium meliloti is a model bacterium for studying the rhizobia-legume symbiosis. Most genes with direct functions in symbiotic nitrogen fixation (SNF) are harboured on two megaplasmids: pSymA (1354 kb) and pSymB (1683 kb). This thesis describes work on minimizing the pSymB replicon to establish a gene complement sufficient for a robust SNF phenotype. It also outlines my contribution towards establishing that 58 genes (63 kb) from pSymA are sufficient for a robust SNF phenotype. Megaplasmid pSymB is evolutionarily older and more chromosomal-like (i.e. a chromid) than the more recently acquired pSymA replicon. Both large-scale deletion analyses (top-down) and assembly-based methods (bottom-up) to minimize pSymB were conducted. These analyses revealed that minimizing pSymB results in a large symbiotic penalty. An initial minimization of pSymB to 261 kb (15%) resulted in SNF with a large degree of plant genotype-dependent variation. This served as a platform to demonstrate that additional regions housing undiscovered auxiliary genes are necessary for the efficient SNF. Accordingly, a minimized 673 kb replicating pSymB that facilitated consistent SNF was isolated. A cumulative deletion strategy refined this set to 276 kb (16% of pSymB) without further SNF impairment. In addition to the deletion approach, we developed a methodology that targeted the assembly of pSymB loci into discrete clusters followed by their iterative integration into a S. meliloti strain lacking pSymB. A set of 101 genes (114 kb) from pSymB proved capable of routinely forming nodules with SNF at 25% wild-type levels. By combining the minimized pSymA and iv pSymB sets, the smallest genome capable of forming root-nodule symbioses was established. This should serve as a powerful chassis for gain-of-function approaches to studying SNF.

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