title: The time machine. Norman Taylor Memorial Lecture 2002

authors: Lowe, David J.

abstract: I've chosen to talk about five topics dealing with longstanding pedological or paleoenvironmental problems involving tephrostratigraphy. I'll begin with the oldest tephras and work 'stratigraphically upwards' to the youngest. Along the way I'll mention or show a few of the people I've worked with, or who were involved historically in the research areas. I've allowed around five or six minutes for each topic (but I'd be grateful if you didn't set your stopwatches!). As promised, the second part of the talk will begin when we reach the year 1952. Among a range of personal observations relating to the birth of the society and to Norman Taylor, I will attempt to explain how I came to be giving this lecture today.

text: The time machine. Norman Taylor Memorial Lecture 2002 I've chosen to talk about five topics dealing with longstanding pedological or paleoenvironmental problems involving tephrostratigraphy. I'll begin with the oldest tephras and work 'stratigraphically upwards' to the youngest. Along the way I'll mention or show a few of the people I've worked with, or who were involved historically in the research areas. I've allowed around five or six minutes for each topic (but I'd be grateful if you didn't set your stopwatches!). As promised, the second part of the talk will begin when we reach the year 1952. Among a range of personal observations relating to the birth of the society and to Norman Taylor, I will attempt to explain how I came to be giving this lecture today.

year: 2002

title: Clonal cell proliferation in the mammary gland

authors: Jacobson, Gregory M.

abstract: The primary aim of this thesis was to classify the nature of the clonal expansion of cells that gives rise to bovine and murine mammary epithelia. It is generally assumed that the mammary gland is derived from the outgrowth of mammary-determined stem cell progeny, and that this expansion produces a mixture of cellular clones throughout the gland. Molecular techniques that enable the 'visualization' of the size and distribution of these clones will lead to a better appreciation of mammary gland development and architecture. 
In female mammals, the simplest 'mark' of clonality is provided by the inactivation of one or the other of the two X chromosomes. This event occurs early in embryogenesis and gives rise to stem cells that propagate this mark in progeny cells throughout the life of the animal. Two approaches, that utilized X-inactivation as a mark of clonality, were investigated, 1) naturally occurring X-linked gene polymorphisms in cattle, and 2) artificially introduced X-linked transgenes in mice. 
The first part of this thesis deals with the isolation and utilization of polymorphic markers on the bovine X-chromosome as markers of clonality. Such expressed genetic markers are essential if one is to distinguish which of the two X-chromosomes is active in a given cell. Two X-linked bovine genes, glucose-6-phosphate dehydrogenase (g6pd) and the X-inactive specific transcript (Xist) were selected for sequencing and SNP detection. As no specific sequence data was available for these genes, a bovine lambda genomic DNA library was screened. The G6PD clone selected from a lambda library was shown to be a pseudogene and therefore not useful for the present study. Another clone, that hybridized with an Xist gene probe, was shown to actually represent a bovine Huntingtin Associated Protein 1 like (Hap1-like) pseudogene, making it of no utility in this study. However, screening of regions of exon 1 of the Xist gene by direct PCR and sequencing, led to the discovery of an informative G↔T single nucleotide polymorphism (SNP). The variation, which was found in frequencies of 0.8 and 0.2 for 'G' and 'T' variants respectively (32% of females are heterozygous), was used in a number of different ways in order to assess the clonal profile of small 'blocks' of the gland (≤30 mm3). In these preliminary experiments, RT-PCR analysis of Xist expression patterns within each of the small blocks (each comprising around 3 X 107 cells) showed general heterogeneity but the experiments were not conclusive. Limitations of the experimental methods used are discussed and suggestions of alternative approaches, that will offer higher resolution, are presented. 
A second experimental approach, involving mice with a reporter transgene construct introduced into the X-chromosome (H253), was also used. The transgene consisted of 14 tandem repeats of a lacZ nuclear-localized reporter gene coupled with a mouse 3-hydroxyl-3-methylglutaryl coenzyme A reductase (hmgcr) promoter (Tam and Tan, 1992). A number of researchers had already utilized this transgenic model, and had confirmed that the cellular patterns of lacZ expression reflected actual X-inactivation patterns in a number of tissues. While carrying out initial investigations to ascertain the utility of this reporter system in investigations of the mammary gland it was discovered that the usual description of hmgcr as a 'house-keeping' gene is somewhat of a misnomer, as some tissues in the mouse show very strong patterns of lacZ expression while others gave minimal, or no, detectable expression. Furthermore, transgene expression was observed to increase during pregnancy and it was concluded that this effect was almost certainly a response to increased estrogen levels at this time. 
Whole mount analysis of five mouse mammary glands from transgenic animals revealed heterogeneous patterns of lacZ staining, indicating that mammary epithelia is generally polyclonal. In total, 42% of terminal buds and alveoli displayed a single lacZ staining pattern. Analysis of these staining patterns induct termini indicated that the majority of individual alveoli are derived from two or three division competent (stem) cells.

text: Clonal cell proliferation in the mammary gland The primary aim of this thesis was to classify the nature of the clonal expansion of cells that gives rise to bovine and murine mammary epithelia. It is generally assumed that the mammary gland is derived from the outgrowth of mammary-determined stem cell progeny, and that this expansion produces a mixture of cellular clones throughout the gland. Molecular techniques that enable the 'visualization' of the size and distribution of these clones will lead to a better appreciation of mammary gland development and architecture. 
In female mammals, the simplest 'mark' of clonality is provided by the inactivation of one or the other of the two X chromosomes. This event occurs early in embryogenesis and gives rise to stem cells that propagate this mark in progeny cells throughout the life of the animal. Two approaches, that utilized X-inactivation as a mark of clonality, were investigated, 1) naturally occurring X-linked gene polymorphisms in cattle, and 2) artificially introduced X-linked transgenes in mice. 
The first part of this thesis deals with the isolation and utilization of polymorphic markers on the bovine X-chromosome as markers of clonality. Such expressed genetic markers are essential if one is to distinguish which of the two X-chromosomes is active in a given cell. Two X-linked bovine genes, glucose-6-phosphate dehydrogenase (g6pd) and the X-inactive specific transcript (Xist) were selected for sequencing and SNP detection. As no specific sequence data was available for these genes, a bovine lambda genomic DNA library was screened. The G6PD clone selected from a lambda library was shown to be a pseudogene and therefore not useful for the present study. Another clone, that hybridized with an Xist gene probe, was shown to actually represent a bovine Huntingtin Associated Protein 1 like (Hap1-like) pseudogene, making it of no utility in this study. However, screening of regions of exon 1 of the Xist gene by direct PCR and sequencing, led to the discovery of an informative G↔T single nucleotide polymorphism (SNP). The variation, which was found in frequencies of 0.8 and 0.2 for 'G' and 'T' variants respectively (32% of females are heterozygous), was used in a number of different ways in order to assess the clonal profile of small 'blocks' of the gland (≤30 mm3). In these preliminary experiments, RT-PCR analysis of Xist expression patterns within each of the small blocks (each comprising around 3 X 107 cells) showed general heterogeneity but the experiments were not conclusive. Limitations of the experimental methods used are discussed and suggestions of alternative approaches, that will offer higher resolution, are presented. 
A second experimental approach, involving mice with a reporter transgene construct introduced into the X-chromosome (H253), was also used. The transgene consisted of 14 tandem repeats of a lacZ nuclear-localized reporter gene coupled with a mouse 3-hydroxyl-3-methylglutaryl coenzyme A reductase (hmgcr) promoter (Tam and Tan, 1992). A number of researchers had already utilized this transgenic model, and had confirmed that the cellular patterns of lacZ expression reflected actual X-inactivation patterns in a number of tissues. While carrying out initial investigations to ascertain the utility of this reporter system in investigations of the mammary gland it was discovered that the usual description of hmgcr as a 'house-keeping' gene is somewhat of a misnomer, as some tissues in the mouse show very strong patterns of lacZ expression while others gave minimal, or no, detectable expression. Furthermore, transgene expression was observed to increase during pregnancy and it was concluded that this effect was almost certainly a response to increased estrogen levels at this time. 
Whole mount analysis of five mouse mammary glands from transgenic animals revealed heterogeneous patterns of lacZ staining, indicating that mammary epithelia is generally polyclonal. In total, 42% of terminal buds and alveoli displayed a single lacZ staining pattern. Analysis of these staining patterns induct termini indicated that the majority of individual alveoli are derived from two or three division competent (stem) cells.

year: 2004

title: Exploring synergies between Māori pedagogy and communicative language teaching

authors: Nock, Sophie

subjects: Māori pedagogy

abstract: The primary aim of this paper is to explore potential synergies between Māori pedagogy and what is known as ‘communicative language teaching’. A brief outline of some changes and developments in approaches to language teaching and learning over the last few decades is followed by a summary of some of the main characteristics of communicative language teaching (CLT) and of different approaches to the conceptualization of Māori pedagogy. Some of the primary characteristics of communicative language teaching are then explored in the context of Māori pedagogy and it is argued that there are some important synergies between the two.

text: Exploring synergies between Māori pedagogy and communicative language teaching The primary aim of this paper is to explore potential synergies between Māori pedagogy and what is known as ‘communicative language teaching’. A brief outline of some changes and developments in approaches to language teaching and learning over the last few decades is followed by a summary of some of the main characteristics of communicative language teaching (CLT) and of different approaches to the conceptualization of Māori pedagogy. Some of the primary characteristics of communicative language teaching are then explored in the context of Māori pedagogy and it is argued that there are some important synergies between the two.

year: 2009-02