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Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [78]-93).

Stem cells have yet to contribute to their full potential in the field of regenerative medicine and further understanding of the underlying kinetics of cell differentiation could be the step forward. Various methods have been used to characterise stem cell lineage commitment. However, most of these techniques are end-point assays and provide very little information about the changes occurring in the early stages of the differentiation process. This project aims to explore if the structural and geometrical specificity of the cytoskeletal components (actin in particular) encode information regarding cell lineage. Adipogenic and osteogenic differentiation lineages were selected, as they have been extensively studied over the past few decades. We have developed a novel approach to describe cells by defining their cytoskeletal and nuclear morphology in terms of 19 geometric measurements. This set of parameters has a range of complexity, extending from one dimensional (e.g. fibre length, fibre thickness) to compound geometrical readings (e.g. chirality and fibre alignment), while some estimate morphological and mechanical properties of the nucleus i.e. Poisson ratio and chromatin condensation. A proprietary image analysis algorithm is used to analyse fluorescent images of cells biochemically and mechanically stimulated to differentiate for a period of up to 10 days. Our analysis pipeline is currently optimised for images acquired at x20 magnification using epi-fluorescence but can be further adapted for high throughput live cell imaging. Factorial analysis of the measured features showed that some parameters change markedly in the early stages of differentiation. More interestingly we observed these changes to be non-linear and non-monotonic. This analysis, in light with previously published literature on the subject has allowed us to more intricately hypothesise probable mechanisms involved with mechanotransduction which direct the lineage commitments. As our technique quantifies the morphology of individual cells, we used our extracted feature data to characterise each cell using a multivariate predictive model (LDA).

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [79]-97).

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18510号 / 医博第3930号 / 新制||医||1006(附属図書館) / 31396 / 京都大学大学院医学研究科医学専攻 / (主査)教授 妻木 範行, 教授 開 祐司, 教授 戸口田 淳也 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Embryonen von Höheren Krebsen (Malacostraca) zeigen ein stereotypes Zellteilungsmuster im Ektoderm des Rumpfes, im Verlaufe dessen paarige seitliche Reihen von Zellen und eine unpaare mittlere Reihe von Zellen gebildet werden. Das Muster der seitlichen Zellen ist von Dohle (1970, 1976) und Mitarbeitern geklärt worden. Die vorliegende Arbeit untersucht die cell lineage und Zelldifferenzierung der Mittellinienzellen im Thorax. Diese Zellen sind von besonderem Interesse, weil sie bei Insekten bereits intensiv erforscht wurden. (i) Die DiI Markierungen von Mittellinienzellen von Orchestia cavimana zeigen: Die Bildung der Mittellinie beginnt mit einer Zelle, die sich zweimal in Längsrichtung teilt. Die resultierenden vier Zellen werden mit a0, b0, c0 und d0 bezeichtet. Aus den Zellen a0, b0 und c0 gehen Paare von Gliazellen hervor. Die Tochterzellen von a0 und c0 umhüllen die Kommissuren. Die Zelle d0 ist ein medianer Neuroblast, aus dem mehrere Neurone hervorgehen, unter anderem ein unpaares Neuron im medianen Fasertrakt, interneurone und ein Motoneuron. (ii)BrdU Markierungen von Porcellio scaber zeigen: In den Ganglienanlagen liegt in der Mittellinie je eine Zelle, die größer ist als die benachbarten, schneller proliferiert und deshalb vermutlich ein medianer Neuroblast ist. (iii) Die Expression von engrailed setzt bei Orchestia und Porcellio ein in der Zelle a0 und wird in den zwei Tochterzellen fortgesetzt. Für Orchestia wird gezeigt, daß diese Expression zurückgeht und die Tochterzellen der Zelle d0 de novo mit einer Expression von engrailed beginnen.Aus den Ergebnissen kann abgeleitet werden, daß der gemeinsame Vorfahr von Insekten und Höheren Krebsen eine Mittellinie differenziert, die Vorläufer für Glia der Kommissuren und einen medianen Neuroblasten umfaßt und eine Expression von engrailed in den Tochterzellen des Neuroblasten zeigt. / Embryos of higher crustaceans (Malacostraca) show a highly stereotypic cell division pattern in the ectoderm of the trunk region while forming paired rows of lateral cells and an unpaired median row of midline cells. By using nuclear dyes, the pattern of the lateral cells has been determined by Dohle (1970, 1976) an co-workers. This study addresses the cell lineage and cell differentiation of the midline cells in the thorax. These kind of cells are of particular interest as they have been investigated extensively in insects. (i) The DiI labelling of midline cells in Orchestia cavimana reveals: Formation of the midline starts with a single midline cell that divides twice in longitudinal direction. The resulting four cells are termed a0, b0, c0, and d0. The cells a0, b0, and c0 give rise to pairs of glial cells. The progeny of a0 and c0 enwrap the commissures. The cell d0 is a median neuroblast that gives rise to several neurons, among them an unpaired neuron in the median fibre tract, interneurons and probably a single motoneuron. (ii) BrdU labelling in Porcellio scaber shows: there is a single larger and faster dividing cell in the midline in each segmental ganglion anlage that is a putative median neuroblast. (iii)The expression of engrailed starts in Orchestia and Porcellio the cell a0 and continues in the two daughter cells during segmentation. In Orchestia it can be shown that this expression ceases and progenies of the cell d0 start de novo with the expression of engrailed. From the results can be concluded that the common ancestor of insects and higher crustaceans differentiated an unpaired midline comprising precursors for glial cells enwrapping the commissures and a single median neuroblast whose derivatives express engrailed.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 88-100).

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 13, 2008). Includes bibliographical references.

Different neurons and glial cells in the Drosophila olfactory circuitry have distinct functions in olfaction. The mechanisms to generate most of diverse neurons and glial cells in the olfactory circuitry remain unclear due to the incomprehensive study of cell lineages. To facilitate the analyses of cell lineages and neural diversity, two independent binary transcription systems were introduced into Drosophila to drive two different transgenes in different cells. A technique called ‘dual-expression-control MARCM’ (mosaic analysis with a repressible cell marker) was created by incorporating a GAL80-suppresible transcription factor LexA::GAD (GAL4 activation domain) into the MARCM. This technique allows the induction of UAS- and lexAop- transgenes in different patterns among the GAL80-minus cells. Dual-expression-control MARCM with a ubiquitous driver tubP-LexA::GAD and various subtype-specific GAL4s which express in antennal lobe neurons (ALNs) allowed us to characterize diverse ALNs and their lineage relationships. Genetic studies showed that ALN cell fates are determined by spatial identities rooted in their precursor cells and temporal identities based on their birth timings within the lineage, and then finalized through cell-cell interactions mediated by Notch signaling. Glial cell lineage analyses by MARCM and dual-expression-control MARCM show that diverse post-embryonic born glial cells are lineage specified and independent of neuronal lineage. Specified glial lineages expand their glial population by symmetrical division and do not further diversify glial cells. Construction of a GAL4-insensitive transcription factor LexA::VP16 (VP16 acidic activation domain) allows the independent induction of lexAop transgenes in the entire mushroom body (MB) and labeling of individual MB neurons by MARCM in the same organism. A computer algorithm is developed to perform morphometric analysis to assist the study of MB neuron diversity.