The development of techniques to distinguish species and strains of giardia : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Microbiology at Massey University

Water supplies, in some rural areas of New Zealand, contain Giardia cysts. This is assumed to make the water unsuitable for human consumption. G. intestinalis and/or G. muris cysts may be present but are not distinguished by the standard test. G. muris infects rodents only so it is not infectious for humans. However G. intestinalis infects humans and a wide range of animals, but it is unclear if the strains which infect animals also infect humans. If G. intestinalis strains are host-specific, then since water in rural areas may contain cysts derived only from animal species it would follow that the water (even if G. muris and/or G. Intestinalis cysts were found) may not be infectious for humans. Investigation of host-specificity of G. intestinalis would be facilitated by a reliable test to distinguish strains of the organism and this thesis investigates the use of PCR for this purpose. A series of random primers were investigated for their ability to distinguish strains of G. intestinalis when used with a variety of PCR protocols. We found that several of these primers (especially GC50 at an annealing temperature of 35°C, and GC80 at an annealing temperature of 35°C) had the potential to distinguish strains. The differences seen were not large but this may be because some of the isolates were clonally related. Consequently we concluded that further modifications and extensions of PCR when applied to human and animal strains should distinguish strains and may have the potential to address the question of host-specificity. The major aim of the thesis however was to produce primers which when used in the PCR are capable of distinguishing G. muris from G. intestinalis. The same approach,ie the use of a random primer, was used to distinguish G. muris from G. intestinalis. Clear differences were seen but the non-specificity of the random primer would allow the organisms to be reliably distinguished only in the absence of other organisms. To avoid this lack of specificity an amplified band produced with G. muris DNA but not with G. intestinalis DNA was sequenced and a primer pair was selected. These primers were, in principle, long enough (21-mer and 23-mer) to be specific for the target DNA and were chosen so as to have matched melting temperatures. The selected primer pair amplified a sequence 307bp long, and the primer sequences were specific for the target species, namely G. muris. Thus in our hands using PCR this primer pair amplified DNA from the available strains of G. muris but failed to amplify DNA from any of seven G. intestinalis strains. Further work is required to establish both an optimal method for lysing cysts and to estimate the minimum number of cysts required to ensure that DNA is available for amplification. However, the availability of the G. muris -specific primers, along with the recently developed genus and G. intestinalis -specific primers should allow us to undertake investigations of water supplies to see if G. muris, G. intestinalis or both species are present. In the case of a small rural supply it would seem reasonable to accept the potability of water supplies containing G. muris only, as long as assurance could be given that G. intestinalis was not present

Teaching socioscientific issues and ethical decision-making : a self-study : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Education at Massey University, Manawatū, New Zealand

The research outlined in this thesis involved reflecting on my teaching practice in a self-study to investigate whether changes could be made to the way I teach ethical decision-making on socioscientific issues. I wanted to improve the students’ ability to justify ethical decisions they made as part of an assessment. During 2011 I actively gathered data for a self-study in science education, investigating my teaching of ethical decision-making to my Year 13 Biology students. I was aware that students were not justifying the ethical decisions they made as part of an assessment done in the course, and wanted to develop their ability to do this. The theoretical framework of this research was constructivism. In the case of this self-study, I considered myself to be the learner, making sense out of what I found. The self-study was conducted in a New Zealand secondary school Biology classroom. The tool used for enabling the students to improve their ethical decision-making is located on the Biotechnology Learning Hub. The Ethics Thinking Tool was developed for use within science classrooms, and provides a selection of ethical perspectives for students to explore. Data were gathered from a range of sources, in particular my professional journal and interviews with a group of students in my Year 13 Biology class. The interviews, held at the conclusion of the course to minimise ethical concerns, focussed on the teaching that had occurred in a unit on socioscientific issues. These interviews, when analysed alongside my professional journal and critical conversations with a mentor, provided a rich source of data. Ten critical incidents occurring within the teaching of this unit were identified as being significant events in terms of either the teaching process or the research process. These were reflected upon and whilst each of these critical incidents revealed insight into my practice, four of them seemed to offer real impetus for change in teaching practice. These four critical incidents were unpacked for further, more in depth, analysis. Four main ideas emerged from the data, one from each of the critical incidents analysed in depth. I now recognise the significant value of being critically reflective on my teaching, particularly when using new teaching tools or resources. The second insight is that I found that my intended outcomes as a teacher did not always match what the students thought the intended outcomes were. Whilst this dissonance did not necessarily impact on the experience for the students, as a teacher it is important to reflect on differing perceptions within the same teaching and learning environment. It also highlights the tension in secondary education between preparation for university versus preparation for citizenship. The third insight is that it is also essential to teach general research skills as well as subject-specific research skills. My fourth insight is that there is significant value in talking to students about more than the content. Further, conversations with a pedagogical focus can be beneficial for both the teacher and the learner. The result of all of these insights has been a shift in how I conduct conversations with students. Only by changing the focus have I been able to make changes that I hope ensure students develop competencies they can use in future contexts. As a consequence of this study I intend to take the notion of self-study back to my school to enable other teachers to use the framework developed as part of this research to explore their practice. This type of innovative inquiry within the secondary setting has the potential to lead to real change in the way teachers reflect on their own practice, allowing them to make informed change that will make a difference for both the teacher and the learners, in a collaborative and supportive environment