title: Characterization of the potential drug target serine acetyltransferase (CysE) from Acinetobacter baumannii: A Pacific lens on biochemical research

authors: Usu, Jessicca Eva

abstract: 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.

text: Characterization of the potential drug target serine acetyltransferase (CysE) from Acinetobacter baumannii: A Pacific lens on biochemical research 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.

year: 2024

title: Synthesis of least restrictive controllable supervisors for extended finite-state machines with variable abstraction

authors: Malik, Robi

subjects: Science & technology

abstract: This paper presents an algorithm that combines modular synthesis for extended finite-state machines (EFSM) with abstraction of variables by symbolic manipulation, in order to compute least restrictive controllable supervisors. Given a modular EFSM system consisting of several components, the proposed algorithm synthesises a separate supervisor for each specification component. To synthesise each supervisor, the algorithm iteratively selects components (plants and variables) from a synchronous composition until a least restrictive controllable solution is obtained. This improves on previous results of the authors where abstraction is only performed by the selection of components and not variables. The paper explains the theory of EFSM synthesis and abstraction and its algorithms. An example of a flexible manufacturing system illustrates how the proposed algorithm works to compute a modular supervisor.

text: Synthesis of least restrictive controllable supervisors for extended finite-state machines with variable abstraction This paper presents an algorithm that combines modular synthesis for extended finite-state machines (EFSM) with abstraction of variables by symbolic manipulation, in order to compute least restrictive controllable supervisors. Given a modular EFSM system consisting of several components, the proposed algorithm synthesises a separate supervisor for each specification component. To synthesise each supervisor, the algorithm iteratively selects components (plants and variables) from a synchronous composition until a least restrictive controllable solution is obtained. This improves on previous results of the authors where abstraction is only performed by the selection of components and not variables. The paper explains the theory of EFSM synthesis and abstraction and its algorithms. An example of a flexible manufacturing system illustrates how the proposed algorithm works to compute a modular supervisor.

year: 2020

title: Aotearoa's heart language: An investigation of compulsory te reo Māori language learning for non-Māori teaching students in Aotearoa New Zealand

authors: Moon, Watene Malcolm Ernest

subjects: Te reo Māori

abstract: Te Reo Māori is becoming more prominent on our airwaves, in government agencies and within schools. Within a wider education system that increasingly seeks to give effect to Te Tiriti o Waitangi, teachers in New Zealand are being asked to become more competent in their development and use of Te Reo Māori, despite over 70% of teachers identifying as New Zealand European. The Teaching Council of Aotearoa New Zealand passed a requirement in 2021 specifying that new teachers should demonstrate Te Reo Māori competency at between level 3 and 4 of the Māori language curriculum by the time they graduate from their initial teacher education. Learning any second language as an adult can be challenging, and so the Teaching Council’s requirement is a big ask, particularly for non-Māori teaching students who may have had little to no exposure to the Māori language prior to enrolling into the teaching programme.

This thesis reports on a qualitative study that investigated the experiences of four non-Māori pre-service teaching students in relation to the requirement that they learn Te Reo Māori as a part of their teaching degree programme. Semi-structured interviews were used to gather data, incorporating culturally responsive approaches during data collection and thematic analysis was undertaken to identify findings. The backdrop for this study was an interpretivist paradigm that recognises the socially constructed nature of each individual’s reality. This research paradigm was appropriate for this research study as I sought to interpret and understand the experiences of each participant with the Teaching Council’s Te Reo Māori requirement. An interpretivist research design also aligns with a qualitative approach to data collection which made this paradigm a good fit for the research project.

The findings suggest that the new Teaching Council requirement is leading to language progress, although there have been challenges for the participants. All four participants have increased their knowledge, understanding and confidence to engage with Te Reo Māori. There was also a noticeable shift in cultural competence amongst all four participants. A very positive outcome when considering that all of the participants came into the teaching programme with little to no experience with Māori language and culture. However, learning Te Reo Māori has at times been confronting for these participants, primarily when historical issues associated with colonisation and the repression of the Māori language have surfaced. Technical aspects of second language acquisition have also caused challenges such as in relation to correct pronunciation and participants’ opportunities to use Te Reo Māori.
 
An over-riding theme from this research has been that although the Teaching Council’s language learning mandate presents an ambitious challenge for pre-service teachers, the four participants in this study have all experienced what can be characterised as a transformative learning process in relation to their Te Reo Māori journey thus far. That is, each participant had learning moments where they were able to critically reflect on their worldview and prior knowledge of Māori language and culture. Through this transformative process not only did the participants gain a deeper understanding of a Māori worldview, but they were able to transition this understanding into their developing teacher practice to the benefit of themselves and their students. While the participants for this study were purposively selected, the positive outcomes evident in their language learning journey suggest that there is potential for this new Teaching Council mandate to be achievable. The findings suggest that this new mandate might be a powerful lever towards a cultural shift for our English-medium teachers and within their classrooms as Te Reo Māori becomes more prominent. This study is also significant because of the scarcity of research on this new policy, and on non-Māori who are required to learn Te Reo Māori as part of their teaching degree. There could be wider significance for this research in the public sphere with attitudes potentially shifting more favourably towards Te Reo Māori and a bicultural country, centred on a Te Tiriti o Waitangi partnership. The findings of this study will be of use to future and current non-Māori teaching students to help navigate this new mandate. Teacher educators could benefit from the implications for culturally responsive teaching and learning. This study may inform researchers in the field of linguistics and education who might wish to build on the results of this research project to inform further studies. Finally, policy makers may be interested to learn about the benefits and challenges that have emerged from this new Teaching Council mandate. Lastly, this research presents an exciting opportunity to showcase this new Teaching Council mandate, and what one participant in the present study described as the ‘heart language’ of New Zealand, with the potential for Te Reo Māori to flourish beyond language classrooms and Māori-medium education and into our mainstream education system, where it belongs.

text: Aotearoa's heart language: An investigation of compulsory te reo Māori language learning for non-Māori teaching students in Aotearoa New Zealand Te Reo Māori is becoming more prominent on our airwaves, in government agencies and within schools. Within a wider education system that increasingly seeks to give effect to Te Tiriti o Waitangi, teachers in New Zealand are being asked to become more competent in their development and use of Te Reo Māori, despite over 70% of teachers identifying as New Zealand European. The Teaching Council of Aotearoa New Zealand passed a requirement in 2021 specifying that new teachers should demonstrate Te Reo Māori competency at between level 3 and 4 of the Māori language curriculum by the time they graduate from their initial teacher education. Learning any second language as an adult can be challenging, and so the Teaching Council’s requirement is a big ask, particularly for non-Māori teaching students who may have had little to no exposure to the Māori language prior to enrolling into the teaching programme.

This thesis reports on a qualitative study that investigated the experiences of four non-Māori pre-service teaching students in relation to the requirement that they learn Te Reo Māori as a part of their teaching degree programme. Semi-structured interviews were used to gather data, incorporating culturally responsive approaches during data collection and thematic analysis was undertaken to identify findings. The backdrop for this study was an interpretivist paradigm that recognises the socially constructed nature of each individual’s reality. This research paradigm was appropriate for this research study as I sought to interpret and understand the experiences of each participant with the Teaching Council’s Te Reo Māori requirement. An interpretivist research design also aligns with a qualitative approach to data collection which made this paradigm a good fit for the research project.

The findings suggest that the new Teaching Council requirement is leading to language progress, although there have been challenges for the participants. All four participants have increased their knowledge, understanding and confidence to engage with Te Reo Māori. There was also a noticeable shift in cultural competence amongst all four participants. A very positive outcome when considering that all of the participants came into the teaching programme with little to no experience with Māori language and culture. However, learning Te Reo Māori has at times been confronting for these participants, primarily when historical issues associated with colonisation and the repression of the Māori language have surfaced. Technical aspects of second language acquisition have also caused challenges such as in relation to correct pronunciation and participants’ opportunities to use Te Reo Māori.
 
An over-riding theme from this research has been that although the Teaching Council’s language learning mandate presents an ambitious challenge for pre-service teachers, the four participants in this study have all experienced what can be characterised as a transformative learning process in relation to their Te Reo Māori journey thus far. That is, each participant had learning moments where they were able to critically reflect on their worldview and prior knowledge of Māori language and culture. Through this transformative process not only did the participants gain a deeper understanding of a Māori worldview, but they were able to transition this understanding into their developing teacher practice to the benefit of themselves and their students. While the participants for this study were purposively selected, the positive outcomes evident in their language learning journey suggest that there is potential for this new Teaching Council mandate to be achievable. The findings suggest that this new mandate might be a powerful lever towards a cultural shift for our English-medium teachers and within their classrooms as Te Reo Māori becomes more prominent. This study is also significant because of the scarcity of research on this new policy, and on non-Māori who are required to learn Te Reo Māori as part of their teaching degree. There could be wider significance for this research in the public sphere with attitudes potentially shifting more favourably towards Te Reo Māori and a bicultural country, centred on a Te Tiriti o Waitangi partnership. The findings of this study will be of use to future and current non-Māori teaching students to help navigate this new mandate. Teacher educators could benefit from the implications for culturally responsive teaching and learning. This study may inform researchers in the field of linguistics and education who might wish to build on the results of this research project to inform further studies. Finally, policy makers may be interested to learn about the benefits and challenges that have emerged from this new Teaching Council mandate. Lastly, this research presents an exciting opportunity to showcase this new Teaching Council mandate, and what one participant in the present study described as the ‘heart language’ of New Zealand, with the potential for Te Reo Māori to flourish beyond language classrooms and Māori-medium education and into our mainstream education system, where it belongs.

year: 2023