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Research Commons is the University of Waikato's open access research repository, housing research publications and theses produced by the University's staff and students.
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Publication Characterization of the potential drug target serine acetyltransferase (CysE) from Acinetobacter baumannii: A Pacific lens on biochemical research(Thesis, The University of Waikato, 2024)Antimicrobial resistance (AMR) presents a critical global health threat, with Acinetobacter baumannii being a key pathogen due to its multidrug resistance. With no new antibiotic classes discovered since the 1980s, novel therapeutic targets are urgently needed. This thesis explores the potential of targeting the cysteine biosynthesis pathway, specifically the enzyme serine acetyltransferase (CysE), as a means to develop innovative antimicrobial strategies. Cysteine plays a pivotal role in bacterial survival and defense, particularly in oxidative stress resistance. Targeting its biosynthesis may impair bacterial virulence and enhance susceptibility to immune responses. This research focuses on the characterization of CysE from A. baumannii, which uniquely expresses a short and full-length of this enzyme. While we were unable to optimize expression of the short form in this thesis, the long form was successfully expressed, purified, and biochemically and structurally characterized for the first time. Using X-ray crystallography, we present the three-dimensional structure of CysE from A. baumannii to a resolution of 2.14 Å. CysE adopts a homohexameric conformation, forming a dimer of trimers, and features an alpha-helical extension. SAXS analysis validated that the long form exists as a homohexamer in solution. Furthermore, using enzymatic assays we show CysE has serine acetyltransferase activity and is sensitive to feedback inhibition by pathway product L-cysteine, highlighting the regulatory mechanisms of this crucial enzyme. This work improves our understanding of cysteine biosynthesis in A. baumannii and provides a model for structure-based virtual inhibitor screening to identify potential new antimicrobials. In addition to its scientific objectives, this research is framed within the Fa'afaletui framework, an Indigenous Samoan methodology that ensures cultural perspectives are integrated into the scientific process. This approach ensures that Pacific values inform the direction of AMR research, fostering solutions that are not only scientifically rigorous but are also culturally relevant and accessible. The research serves to address the health inequities faced by Pacific peoples, particularly in relation to infectious diseases and AMR, and provides a foundation for future antimicrobial drug development efforts.Publication Evaluating the impact of authenticity and person-organisation fit on work attitudes(Thesis, The University of Waikato, 2024)Person-Organisation (PO) Fit and authenticity play an important role in generating positive work attitudes such as job satisfaction, organisational commitment, organisational belonging and turnover intentions. However, the question remains: which is more important? Is one more closely related to these work attitudes? As such, this study explores the correlations of PO Fit and trait and state authenticity with job satisfaction, organisational commitment, organisational belonging and turnover intentions, as well as comparing the significance of their contribution towards these work attitudes. A sample of 285 participants drawn from the general population and University of Waikato undergraduate students completed an online questionnaire examining these concepts, and the hypotheses and research questions were empirically tested using correlation and multiple regression analyses. The results found that both PO Fit and state authenticity were significant contributors to job satisfaction, organisational commitment, organisational belonging and turnover intentions. Notably, one measure of PO Fit – the Person Organisation Fit Questionnaire emerged as the most significant contributor to all our chosen work attitudes. This study is among the first to compare PO Fit and authenticity on work attitudes, enriching the existing literature and offering vital insights for organisations. Indeed, it highlights the importance of prioritising PO Fit to enhance job satisfaction, nurturing organisational commitment and belonging, and reducing turnover intentions. Future research recommendations include investigating additional components within the broader Person-Environment fit framework, such as person-supervisor, person-job, and person-group fit, to better understand their influence on work attitudes. Additionally, intervention studies are recommended to evaluate strategies aimed at enhancing PO Fit and authenticity, and to assess their impact on positive work attitudes.Publication The effects of allelic hinge variation in IgG3 antibodies on protein dynamics and effector functions(Thesis, The University of Waikato, 2024)Antibodies play a crucial role in eliminating infections by recognising foreign antigens with high specificity and affinity. If a target is not directly neutralised, antibodies can mediate potent effector function responses by coordinating the recruitment of immune cells through their constant regions. These powerful immune functions are being widely explored in the form of IgG-based monoclonal antibody therapies for the treatment of infections, cancer, and autoimmune diseases. However, the antibody constant region exhibits significant genetic polymorphism, and new variants are rapidly being discovered by advances in genomic sequencing techniques. The documented effects of this diversity include differences in structural dynamics, thermal stability, and Fc-mediated effector functions among a number of antibody subclasses, including IgG1, IgG2, and IgG3. Some variants are reported to be a contributing factor to variability in the outcome of disease and responsiveness to vaccines in humans. The IgG3 subclass, in particular, displays striking differences in the antibody hinge region – responsible for connecting target binding with constant-region-mediated immune function. Here, exon duplications mean the hinge region can vary by as many as 45 amino acids in length. This work seeks to better understand some of the functional consequences of this unusual IgG3 variation. To assess the effects of allelic hinge variation on protein dynamics and effector functions, we have expressed a panel of seven anti-CD20 antibodies with unique constant region allele sequences from subclasses IgG1, IgG2, and IgG3. Sequence verified plasmids were used to express full-length antibodies in HEK293 cells at high purity. We first used small angle X-ray scattering (SAXS) to assess the variability in size and structural flexibility between the allelic variants and compared our data with previous research on the same variant panel with antiHER2 variable domain sequences. Following this structural analysis, we next undertook ADCC (antibody-dependent cellular cytotoxicity) and ADCP (antibody dependent cellular phagocytosis) assays to determine if differences in structural dynamics between the polymorphic variants could be linked to differences in effector function. These assays specifically used genome-engineered reporter cell lines to evaluate the ability of allelic variants to engage constant region binding FcyRIIIa and FcyRIIa Fc receptors, typically found on peripheral blood mononuclear cells. Activation was measured by quantifying the levels of luciferase expressed as a reporter. The findings provided in this study demonstrate that allelic variants with longer hinges have larger and more flexible structures and tend to present weaker ADCC and ADCP responses. The data presented here is the basis for future work on the influence of IgG constant region diversity on antibody structural dynamics and effector functions, which could contribute to improvements in the design of therapeutic antibodies.Publication Māori engagement with early childhood education in a low-socioeconomic area(Thesis, The University of Waikato, 2024)The early childhood education (ECE) options available to parents in New Zealand are many and varied. As a country New Zealand values ECE and has a high rate of engagement. However, despite a number of government initiatives targeting Māori and those from lower socio-economic areas Māori engagement remains low. This is widely acknowledged and the challenge is to not only find the reasons why but to also be responsive to the causes for low engagement. Early learning services in New Zealand follow a curriculum that considers an holistic approach with the child at the centre of the learning. That curriculum is Te Whāriki: He whāriki mātauranga mō ngā mokopuna o Aotearoa. The curriculum recognises the potential of children and the importance of belonging in developing the whole child. ECE in New Zealand is important for children who are aged zero to five. It is during these early years that children will begin to develop an understanding of the world around them. The environment that children live in is important to their development and it is generally considered that those from low socio-economic areas are less likely to succeed than those from higher socio-economic areas. This thesis investigated Māori engagement in ECE from one low socio-economic area in New Zealand using an overarching Kaupapa Māori methodology. Semi-structured interviews were held with five participants from the low socio-economic area using a case study research design. My analysis found that there were many reasons behind the parents' decisions to send their children to ECE or not. It can be concluded that Māori engagement with ECE is dependent upon parents’ early life experiences and their cultural values.Publication The athleticism of drag queen practices and performance: A mixed-methods study of injury, prevention, and health care(Thesis, The University of Waikato, 2024)Most research on drag performance has focused on gender and sexuality and/or performing arts. To date, very little has examined drag queens’ experiences of athleticism, injury, and injury care. This research provides insights into the physical experiences of professional drag queens, and the relationship of drag queens to health care, in Aotearoa New Zealand and the United States. Specific areas of inquiry include: how drag queen performers of diverse gender identities, ages, experience levels, and athletic backgrounds experience the use of their bodies in their practice of drag; injury occurrence related to drag queen performance; and how drag queens perceive, access, and experience health care in direct connection to their drag practice. A mixed-methods approach was employed, combining a survey (96 participants) and interviews with six drag queens from Aotearoa New Zealand the U.S. This research draws on Queer and feminist theory, as well as public health models, to inform data collection and analysis techniques. The findings reveal drag to be a physically demanding discipline: the majority of drag queens have experienced drag-related injuries, despite practicing personally developed body maintenance behaviours. Participants also expressed a lack of, and necessity for, widely available, fully accessible, and visible LGBTQ+ and drag culturally safe and resonant healthcare. These insights contribute to a broader understanding of the physical body in drag queen performance, as well as the health care needs of drag queens in Aotearoa New Zealand and the United States. Utilization of research findings, along with cross-sector discussions, could inform community health best practices and policy development, to improve health care for this historically marginalized population.
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