Dissertations / Theses: 'Embryology'

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Ali, Asif. "Transcription factors in parathyroid development and embryology." Thesis, Open University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489906.

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The roles of two transcription factors, GATA3 and PARAFIBROMIN, that are involved in parathyroid function have been studied. Thus, loss of function mutations of the dual zinc finger transcription factor GATA3 result in hypoparathyroidism-deafness-renal dysplasia (HDR) syndrome; whilst loss of function mutations of PARAFIBROMIN which is a nuclear protein with a likely role in the RNA polymerase complex, lead to the hyperparathyroidism-jaw tumour (HPT-JT) syndrome.

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Zhao, Xuan. "Conception and fabrication of reusable microfluidic tools to study the dynamics of biological phenomena : application to antibiotic influx/efflux in bacteria and to cell migration during mouse development." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS226/document.

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Nous voulons mettre en évidence et analyser les réponses de systèmes biologiques à l’introduction de perturbations et de modulations spatio-temporelles. Plus précisément, afin de développer des stratégies innovantes pour l’étude des systèmes biologiques, nous proposons d’utiliser des outils microfluidiques. Nous concevons des microsystèmes adaptés qui peuvent influer localement sur les comportements biologiques, ceci afin qu’un experimentateur macroscopique puisse contrôler l’environnement externe des objects biologiques dont l’échelle est microscopique. Cette stratégie d’ingénierie est générique et multidisciplinaire. Au cours de cette thèse, elle a été mise en œuvre dans le cadre de deux projets collaboratifs, d’une part à l’échelle de la bactérie E.coli, et d’autre part à celle de l’embryon de souris à un stade post-implantation précoce. Les objets d’étude choisis sont caractéristiques à bien des égards des champs biologiques concernés : taille, représentativité, complexité.Nous avons mis nos compétences de spécialistes en conception et en fabrication de dispositifs fluidiques au service de la ligne DISCO du synchrotron SOLEIL et de l’équipe d’embryologie de la souris de l’IRIBHM. Le nœud de mon travail a été de concevoir et fabriquer les outils microfluidiques réutilisables pour des recherches génériques, qui permettent aux biologistes de se dispenser de l’utilisation d’une salle blanche.Plus précisément, le projet de microbiologie à SOLEIL avait pour object l’étude de l’influx et l’efflux de molécules antibiotiques dans des bactéries. Pour ce faire, nous avons developpé un dispositif réutilisable pour immobiliser les microorganisms et changer leur environnement chimique pendant l’imagerie en microscopie d’epifluorescence dans l’UV. Cette étude s’effectue en utilisant deux partenaires typiques : la bactérie Escherichia coli et un médicament de la famille des fluoroquinolones. Le projet d’embryologie a reposé sur l’électroporation localisée d’acides nucléiques au sein d’embryons de souris et le suivi des migrations cellulaires. Au cours de cette thèse, nous avons développé non seulement des microdispositifs réutilisables mais aussi des protocoles expérimentaux adaptés à l’utilisation de ces instruments miniaturisés.Plus précisément, le projet de microbiologie à SOLEIL avait pour object l’étude de l’influx et lantibiotiques dans des bactéries. Pour ce faire, nous avons developpé un dispositif réutilisable pour immobiliser lesmicroorganismes et changer leur environnement chimique pendant l’imagerie en microscopie d’épifluorescence dans l’UV.Cette étude s’effectue en utilisant deux partenaires typiques : la bactérie E. coli et un médicament de la famille desfluoroquinolones. Le projet d’embryologie a reposé sur l’électroporation localisée d’acides nucléiques des embryons desouris et le suivi des migrations cellulaires
We want to analyze the responses of biological systems to the introduction of perturbations and spatio-temporal modulations. More specifically, in order to develop innovative strategies for the study of biological systems, we propose to use microfluidic tools. We design adapted microsystems that can locally influence biological behaviors, so that a macroscopic experimenter can control the external environment of biological objects whose scale is microscopic. This engineering strategy is generic and multidisciplinary. In this thesis, it has been implemented in two collaborative projects, on one hand, on the scale of the E.coli bacterium and on the other hand on that of the embryo of mouse at an early stage post-implantation. The selected study objects are characteristic in many respects of the biological fields concerned: size, representativeness, complexity.We extended our expertise in fluidic device design and manufacturing to the service of the DISCO beamline of the synchrotron SOLEIL and the IRIBHM mouse embryology team. The key point of my work has been to design and manufacture reusable microfluidic tools for generic research, which allow biologists to dispense with the use of a clean room.More precisely, the project of microbiology at SOLEIL had for object the study of the influx and the efflux of antibiotic molecules in bacteria. To do this, we have developed a reusable device for immobilizing microorganisms and changing their chemical environment during UV imaging on epifluorescence microscopy. This study is carried out using two typical partners: the Escherichia coli bacterium and a drug from the fluoroquinolone family. The embryology project relied on the localized electroporation of nucleic acids within mouse embryos and the monitoring of cellular migrations.In this thesis, we have developed not only reusable micro-devices but also experimental protocols adapted to the use of these miniaturized instruments.More precisely, the microbiology project at SOLEIL focused on the influx and the efflux of antibiWe have developed a reusable device for immobilizing those microorganisms and changing their chemical environmentduring UV imaging on an epifluorescence microscopy. This study was carried out using two typical partners: thebacterium and a drug from the fluoroquinolone family. The embryology project relied on the localized electroporation ofnucleic acids into mouse embryos and the monitoring of cell migrations

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Lowe, James William Edward. "The role of normal development in experimental embryology." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18014.

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This thesis presents an examination of the notion of 'normal development' and its role in biological research. It centres on a detailed historical analysis of the experimental embryological work of the American biologist Edmund Beecher Wilson in the early-1890s. Normal development is a fundamental concept in biology, which underpins and facilitates experimental work investigating the processes of organismal development. Concepts of the normal and normality in biology (and medicine) have been fruitfully examined by philosophers. Yet, despite being constantly used and invoked by developmental biologists, the concept of normal development has not been subject to substantial philosophical attention. In this thesis I analyse how the concept of normal development is produced and used in experimental systems, and use this analysis to probe its theoretical and methodological significance. I focus on normal development as a technical condition in experimental practice. In doing so I highlight the work that is required to create and sustain both it and the work that it enables. Variation between embryos can cause problems for scientists trying to produce valid and comparable results. In my study of Wilson's work, I examine how the practices associated with normal development deal with the variation between embryos. In the 1890s, Wilson became increasingly interested in which causes were responsible for the processes of differentiation (the production of different cells and organs) and determination in the process of embryonic development. He performed a series of experiments on the marine invertebrate Amphioxus, which exhibits considerable variability in early development (Wilson, 1893a). Wilson carefully observed his samples and outlined a normal development based on them, which included a considerable range of variation. How Wilson treated variation was reflected in the different way in which he conceived of the process of development compared to other prominent embryologists, such as Hans Driesch and Wilhelm Roux. 4 Having introduced and assessed normal development, I use two analytical approaches to make further sense of it. Furthermore, these approaches identify why appreciating the role of normal development enables us to understand important aspects of scientific practice, such as experimental methodology and making causal attributions based on the results of experimental manipulations. The two main analytical approaches I use are James Woodward's manipulationist theory of causation (Woodward, 2003 and 2010), and Hans- Jörg Rheinberger's experimental systems approach (Rheinberger, 1997). The former assesses the factors involved in assessing proposed causal factors, rather than simply demarcating between causes and non-causes. The latter focuses on the way experimental set-ups are configured by scientists in ongoing series of experiments to frame phenomena of interest: 'epistemic objects'. My experimental systems are produced and reproduced, and to how attributions of causality which arise from experimental work are made.

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Leclerc, Benoît. "Studies on prolactin and its receptor during late embryogenesis in turkeys and chickens." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102673.

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Changes in the levels of expression of the prolactin receptor (PRLR) mRNA in the pituitary gland, hypothalamus, liver, pancreas, kidney and gonad from embryonic day (ED) 15 and ED21 to 1 day post-hatch, respectively, in chickens and turkeys were measured by real-time PCR. In both species, PRLR mRNA increased from low levels during the last week of ED to reach maxima at the peri-hatch period. Similarly, circulating levels of prolactin (PRL) also increased during this interval and were correlated with the observed increases in tissue content of PRLR mRNA. This suggested that PRL was up-regulating its own receptor during late embryogenesis. In support of this, in vitro stimulation of the pituitary gland of turkeys with VIP on ED24 resulted in a 4 fold and 3 fold increase in PRL and PRLR, respectively. Stimulation with VIP of either the hypothalamus or gonad had no effect on either levels of the PRLR transcript. This suggests that VIP acts indirectly through increased PRL to upregulate the number of receptors. In order to investigate the transcription of genes that may be induced/suppressed by PRL, suppressive subtractive hybridization (SSH) libraries from control or VIP stimulated ED24 turkey pituitary glands were constructed. Stimulation with VIP resulted in a 5.7 and 2.8 fold increase in media and pituitary content of PRL, respectively. The changes in PRL were consistent with endogenous levels of PRL observed just prior to hatch. Following sequence analysis of random clones (n=96) from each library, a total of 145 non-redundant putative genes were obtained. About 51% of the putative genes have as yet no assigned function, whereas, 15% were housekeeping genes and 34% had known functions within various pathways. Real-time PCR was used to confirm the differential expression of 21 of these genes in VIP treated and control pituitaries. Since the majority of these genes were expressed at levels consistent with the direction of subtraction, these data suggest that these libraries may be useful to study the direct and indirect effects of increasing levels of PRL on anterior pituitary function at about the time of hatch.

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Bentil, Daniel Ekow. "Aspects of dynamic pattern generation in embryology and epidemiology." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276528.

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Lewin, Paul Dominic. "Embryology and the evolutionary synthesis : Waddington, development and genetics." Thesis, University of Leeds, 1998. http://etheses.whiterose.ac.uk/1455/.

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The role of embryology, genetics and morphology within mid twentieth century evolution theory, is discussed in the context of the growth to dominance of natural selection as the orthodox mechanism of adaptive evolution. The unification of neo-Mendelian heredity and neo-Darwinian selection theory, is descnbed as the core of modern synthetic neo-Darwinism as it emerged in 1930s mathematical population genetics. As selectionism strengthened within synthetic neo-Darwinism, embryological development was excluded from its traditional causal role in adaptive evolution within the "old synthesis" of Haeckelian recapitulation and neo-Lamarckian inheritance. A two-tier embryology was created, as embryology was understood to deal separately with the experimental analysis of ontogenetic development, and the historical descriptive analysis of phylogenetic lineages. Neither tier informed the other, or played any direct causal role in the mechanism of the creation of adaptive evolutionary novelty. That adaptive evolutionary mechanism was entirely the preside of natural selection. However, as the selectionist synthesis hardened in the 1940s, late nineteenth century Darwinists' concerns over the hereditary fixation of highly specific adaptive somatic modifications resurfaced. Consequently, the strategic defence of the synthetic theory against any resurgence of neo-Lamarckian heredity, involved an appeal to the principles of modem synthesis developmentalism; namely, the developmentalist syntheses of Waddington and Schmalhausen. The unforeseen implication of these moves by founding supporters of the synthetic theory, was that the disciplines upon which 1940s developmentalism rested--namely, Western chemical embryology and Soviet evolutionary morphology--did after all playa central and causal role in the mechanism of adaptive evolution. Attempts to characterise the alternative and developmentalist syntheses of Waddington and Schmalhausen as the "missing links" to an otherwise incomplete modem synthesis, are historically evaluated. These attempts are thought to embody either a mistaken understanding of the essential nature of synthetic neo-Darwinism, or an obfuscation of the continuing issue of its synthetic adequacy.

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Joyce, Bradley. "Elucidating the molecular mechanisms underlying cell movements during early embryogenesis." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589616.

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The anterior visceral endoderm (AVE) is a specialised subpopulation of the visceral endoderm (VE), a single layer simple epithelium that surrounds the extra-embryonic ectoderm and epiblast of the egg cylinder stage embryo. Initially induced at the distal tip of the egg cylinder, AVE cells undergo a stereotypic migration towards the prospective anterior, stopping at the interface between the underlying epiblast and extra-embryonic ectoderm (ExE). Previous research has shown that membrane enrichment of Dvl2 is present in the VE overlying the epiblast (Epi-VE). In this thesis I confirm the presence of planar cell polarity (pep) signalling in this region by assaying the subcellular localisation of additional core pep proteins Vangl2 and Daaml. I show that null embryos of the Nodal antagonist Lefty1 exhibit ectopic membrane enrichment of Dvl2 and a previously unreported AVE over-migration phenotype. Furthermore, using pharmacological inhibition of Nodal signalling I show that the TGF~ protein Nodal modulates pep signalling in the YE. Utilising DIe and confocal microscopy I perform detailed time-lapse analyses of the VE to quantify the dynamic cell behaviour and topology. Using this assay I show that wild-type embryos exhibit dynamic cell movement, which is regionally restricted to the Epi-VE. Analysis of Leftyl-/- and ROSA26lyn-Celsr-l mutants, both of which exhibit disrupted pep signalling and AVE over-migration phenotypes, indicates that normal VE dynamics and topology are disrupted. The results of this quantitation indicate that these mutants exhibit increased cell migration and neighbour exchange across the YE. These data show that regional restriction of movement is lost and results in the AVE over-migration phenotypes observed. Together these results show that regionally restricted pep signalling in the VE acts to modulate cell behaviour and topology, which in turn determines the regional restriction and normal end-point of AVE migration.

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Teo, Roy Tang Yi. "Molecular mechanisms of primitive endoderm formation." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610366.

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Levy, Jean Elizabeth. "Controlling the course of scientific advance : the case of human embryology." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440422.

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Svennilson, Johan. "The developing rat kidney : the dopamine system and related serine/threonine kinases and phosphatases /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3764-8/.

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Poirier, Luc. "The degradation of the stem-loop binding protein at the late 2-cell stage of mouse embryogenesis /." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80351.

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The efficient processing of replication-dependent histone mRNA requires the Stem-Loop Binding Protein (SLBP). SLBP is also involved in regulating histone mRNA half-life, their nucleocytoplasmic transport, and their translation. Unlike somatic cells, where SLBP protein accumulates only in S-phase, SLBP protein is present throughout the first two embryonic cell cycles in mice. We report here that in late 2-cell mouse embryos there is a substantial, proteasome-dependent decrease in SLBP throughout the cell. Based on chromosome morphology, the degradation of SLBP protein in late 2-cell embryos is most likely a late G2-phase event. The degradation of SLBP protein is not simply a zygotic clock event, but requires development to the late 2-cell stage. Furthermore, SLBP protein degradation in 2-cell mouse embryos requires cyclin-dependent kinase (Cdk) activity, DNA replication, and zygotic genome activation. A model for SLBP protein degradation is proposed based on observations made in both early mouse embryos and somatic cells.

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Hatada, Yohko. "Axis formation in the chick embryo." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260737.

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Dokras, Anuja. "Human trophectoderm biopsy and its application." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306010.

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Solly, John Christopher. "PDZ proteins in cellular asymmetry during Drosophila embryogenesis." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613280.

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Perriton, Claire. "The development and evolution of vertebrate external genitalia." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275446.

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Hewitson, Laura Charlotte. "Energy metabolism of the trophectoderm and inner cell mass of the mouse blastocyst." Thesis, University of York, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358202.

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Strachan, Lorna. "Establishment of Hox gene expression domains along the anteroposterior axis of the chick embroyo." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242946.

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O'Shaughnessy, Aoife Margaret. "The chromatin remodeller Mi-2β is required for early embryonic cell development." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610848.

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Mola, Choulia. "Identification of oocyte reprogramming factors and mechanisms." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42492/.

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The ability of the oocyte to reprogram paternal chromatin is widely accepted. The oocyte cytoplasm has been reported to contain activities that alter the histone composition, demethylate and unwind highly methylated paternal DNA upon fertilization and lead to zygote formation. The same events are mimicked during the course of cell reprogramming, where somatic cells exposed to the oocyte environment acquire a pluripotent character. Amphibian oocytes have been widely used to study the reprogramming attributes of the female germ cells for over half a century. The size of amphibian oocytes renders them good candidates for technical manipulations, as well as protein biochemistry studies. Oocytes harvested from the amphibian axolotl were utilised in the present study to delineate the oocyte reprogramming machinery. Previous studies have reported the presence of key pluripotency factor orthologs, such as Nanog, in the axolotl oocyte, thus rendering it an interesting tool for the study of the chromatin remodelling and pluripotency networks as well as their interplay. To study these networks, identification of the physical interactors of the Nanog protein or the Nanog promoter was attempted. One of the key events taking place during cell and paternal chromatin reprogramming is demethylation. The removal of the methyl mark that is deposited over genetic loci during cell differentiation is linked with the transcriptional activation of the respective loci. Demethylation is therefore fundamental for the activation of pluripotency-associated factors both in fertilisation and cell reprogramming. The leading theory behind demethylation is the successive oxidation of the methyl mark to formyl and carboxyl and its subsequent removal from Thymine DNA Glycosylase (TDG). Ten Eleven Translocation (TET) family proteins catalyse methyl oxidation and therefore utilise demethylation. Additional demethylation pathways have also been supported by findings, specifically in the context of the oocyte. Base Excision Repair (BER) and Nucleotide Excision Repair (NER) factors have been associated with DNA demethylation occurring immediately after fertilisation. It is therefore fundamental to delineate the demethylation mechanism facilitated by the oocyte in the early stages of development. The identification of oocyte demethylation factors and mechanisms will greatly improve our understanding of demethylation as well as improve current cell reprogramming methodologies by using the more efficient oocyte demethylation mechanism. To delineate the demethylation mechanism employed by the oocyte and contribute to the debate of TET oxidation versus NER or BER demethylation via DNA repair in the context of the oocyte, oocyte factors preferentially binding to different cytosine modifications were analysed. The murine Nanog promoter, a genetic locus activated during cell reprogramming, harboured the different cytosine modifications in an attempt to see how each one would affect its transcriptional status. As a result, TET factors were not discovered to bind any of the cytosine modifications while both NER and BER pathway proteins were found to be significantly enriched in the case of methylcytosine. The results obtained therefore support previous findings and advocate for a TET independent DNA demethylation occurring through DNA repair. While teams researching demethylation through DNA repair have supported either NER or BER, the findings unveiled in this thesis advocate for the two pathways acting in concert in the recognition and potential removal of DNA methylation. It also has to be noted that it is the first time an experiment of this kind is carried out in the context of the oocyte and the findings offer a unique insight into oocyte demethylation dynamics. Taking into account the data obtained and previous research, a new DNA demethylation model is proposed. The model advocates for NER taking the lead in DNA demethylation, creating patchy demethylated sites that are subsequently recognised and demethylated via the BER pathway.

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Watson, Catherine E. "The permeability of Drosophila melanogaster embryos." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29203.

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Drosophila are used extensively for genetic, developmental and now molecular biology research. At present, germline transformation of these organisms can only be achieved by microinjection of P-element vectors into the pole cells of young embryos. The technique of microinjection however, requires a delicate touch and is quite laborious. Therefore, the development of a rapid and simple technique was investigated. Electroporation, like microinjection, is a physical means of introducing DNA into a cell and is therefore potentially applicable to all cell types. Electroporation involves the use of an electrical current to create pores in the membrane of a cell. Macromolecules, such as DNA may enter a cell via these pores. Electroporation is a quick, reproducible, and efficient method for transforming cells. Through studies of the survival and permeability of Drosophila melanogaster embryos exposed to electrical currents, it was discovered that although the survival of the embryos decreased steadily as field strength increased, the embryos did not become permeable to a water soluble dye unless a pulse of 10 kV/cm was applied. Few embryos survived this extreme voltage required for dye uptake. Attempts to introduce DNA into dechorionated Drosophila embryos utilizing this technique however, produced no transformants. These results suggested that the remaining protective coatings of the dechorionated embryo were obstructing efficient pore formation, thus preventing DNA penetration. In view of these results, methods to eliminate the wax layer, present between the chorion and vitelline membrane of laid eggs, were examined. Wax removal by detergent solubilization, solvent extraction and melting by heating were investigated, yet did not produce a satisfactory procedure.
Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate

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Lytvynenko, D. S. "Sir John Bertrand Gurdon and his contribution to histology, cytology and embryology." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/31965.

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Sir John Bertrand Gurdon (born 2 October 1933) is a British developmental embryologist. He is best known for his pioneering research in nuclear transplantation and cloning. He was awarded the Lasker Award in 2009. In 2012, he and Shinya Yamanaka were awarded the Nobel Prize for Physiology or Medicine for the discovery that mature cells can be reprogrammed to become pluripotent. His Nobel Lecture was called "The Egg and the Nucleus: A Battle for Supremacy". When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31965

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Meunier, R. "THICK AND THIN CHARACTERS:ORGANISMAL FORM AND REPRESENTATIONAL PRACTICE IN EMBRYOLOGY AND GENETICS." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/214613.

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In this thesis the family of concepts, including characters, traits and phenotypes of organisms is analyzed according to the various roles these concepts play in different disciplines and in different historical periods. The ways the concepts are construed in order to fulfill their roles are spelled out in terms of the representational practices in which these concepts are embedded. In particular, I look at classical genetics in the period spanning from Mendel to Morgan and compare the character concept that gradually developed in this period – and which I characterize as a thin concept, meaning that characters appear as values of variables that are represented in articulated symbol systems – with the thick concept of parts, properties and processes as it prevails in anatomy, physiology and embryology. In order to illustrate that both concepts still play their role in modern biology and to address the question of their possible integration, I conclude by briefly looking at current developmental genetics. I address the general issue of scientific pluralism in Chapter 1. Chapter 2 and 3 introduce the methodological concepts necessary to analyze the representational practices that embody the various character concepts. Chapters 4, 5, 6 and the Conclusion contain the discussion of the character concepts in the disciplines taken into consideration.

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Woll, Steven Cody. "Insulin-like Growth Factor Pathway Described in Austrofundulus limnaeus Diapause and Escape Embryos." PDXScholar, 2016. https://pdxscholar.library.pdx.edu/open_access_etds/3207.

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Development in the annual killifish Austrofundulus limnaeus can follow two distinct developmental trajectories. Typical development includes the entrance of embryos into a state of metabolic and developmental arrest termed diapause. Alternately, embryos can escape diapause and develop directly without pause. These two trajectories are characterized by differences in the rate and timing of developmental, morphological, and physiological traits. Insulin and Insulin-like growth factor (IGF) signaling (IIS) is known to regulate entrance into diapause in a variety of invertebrates. In this thesis I explore the possible role of IGFs in the regulation of development and diapause in embryos of A. limnaeus. Here I report stage-specific expression of IGF-I and II proteins and their associated mRNA transcripts. Patterns of IGF-I protein expression are consistent with IGF signaling playing a major role in supporting the escape trajectory. In addition, treatment of embryos with a potent inhibitor of the IGF-I receptor (IGF1R) mimics the diapause developmental pattern even under conditions that should favor direct development. Evaluation of mRNA gene expression patterns in the two developmental trajectories suggests a role for IGF-I signaling through the RAS-MAPK-ERK pathway, which may be promoting the escape phenotype. Additionally, IGF-I activity may be enhanced in escape trajectory embryos though upregulation of IGF binding protein 2 (IGFBP-2) mRNA. These data suggest a major role for IGF signaling in the promotion of the escape trajectory, and thus we predict that specific mechanisms are in place in diapause-bound embryos that block IGF signaling and thus promote entrance into diapause. The data presented here suggest that blocking IGF signaling is critical for induction of diapause, but also suggests that other signaling pathways are likely also at play. Other pathways such at the TGF-beta signaling molecules and SMAD pathway, may also be involved in the direct regulation of the diapause phenotype, as has been shown for other animal models of developmental arrest.

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Kelsh, Robert Neil. "Some aspects of bithorax complex expression in Schistocera gregaria embryogenesis." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386146.

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Swiers, Gemma. "A single mix gene in the axolotl - investigating mesendoderm and blood specification." Thesis, University of Nottingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493346.

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All the tissues within the developing embryo are comprised of cells formed from one of the three germ layers defined during gastrulation; the ectoderm, mesoderm and endoderm. Understanding how the germ layers are formed and subsequently differentiate into different tissues is the basis of developmental biology.

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Kidd, Thomas. "Genetic and molecular studies of early embryogenesis in Drosophila." Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:2832c843-43ef-48bf-9674-abf1029caf78.

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The Drosophila embryo is patterned by a complex interplay of zygotically expressed genes and maternally supplied components, a large number of which have been identified. However, many maternal components are encoded by essential zygotic genes whose maternal effects are not amenable to conventional genetic analysis. Investigation of such genes requires the generation of homozygous mutant germ cells in chimeric females, and analysis of their embryos. The recent development of techniques which allow the efficient generation of germline clones has made the screening of zygotic lethal mutations for maternal effects more feasible. I have generated a collection of X-linked zygotic lethal mutations and used FLP recombinase catalysed mitotic recombination to look for maternal effects affecting segmentation. Two mutations have been recovered which have maternal effect phenotypes similar to those of the pair-rule segmentation genes. The leprechaun mutation affects oogenesis, so fertile females are very rare, preventing straightforward phenotypic analysis of the segmentation phenotype. Attempts to generate a rescuing duplication are described. The second mutation, stunted (sun), initially gave rise to a segmentation cuticle phenotype. Subsequent attempts to reproduce the phenotype were unsuccessful as it was masked by a severe reduction in the amount of cuticle secreted, a phenotype characteristic of the neurogenic genes. Detailed analysis revealed that the primary lesion affects neither segmentation or neurogenesis. Rather, sun⁺ is required for cellularisation of the syncytial blastoderm and for the localisation of actin to 'caps' above the syncytial nuclei. Cloning of a candidate gene for stunted revealed a predicted protein product limited homology to cyclins. In addition to searching for novel segmentation genes, potential proteinprotein interactions of the segmentation gene hairy's protein product were also investigated, and a model is presented for its mode of action as a transcriptional repressor.

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Adi, Mohamad M. "Aspects of the structure and function of the human salivary glands." Thesis, University of Dundee, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260121.

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Sepulveda-Rincon, Lessly P. "Cell allocation patterns during mammalian pre-implantation development." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43031/.

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The first cell differentiation in the mammalian embryo occurs during pre implantation development. At blastocyst stage two cell lineages can be distinguished: the inner cell mass (ICM), situated at the embryonic pole and the trophectoderm (TE) at the abembryonic pole. In murine embryos, it has been suggested that the first cleavage plane might be related with the embryonic-abembryonic (Em-Ab) axis at the blastocyst stage. So the daughter cells of the two-cell embryo might be already predisposed to a specific cell lineage further on development. The objective of the present thesis is to investigate the effects of assisted reproductive technologies (ART) factors affecting cell allocation patterns during pre implantation development. This was addressed by observing cell allocation patterns during mammalian pre implantation development on embryos produced using different ARTs. Using live-cell tracing, it has been concluded that cell allocation patterns during pre-implantation embryo development are potentially conserved among mammals, or at least among mouse and bovine embryos. Pre determined (orthogonal and deviant patterns), as well as stochastic development (random pattern), have been identified in mouse and bovine embryos. The incidence of these cell allocation patterns was not affected by maternal age, oocyte production, oocyte fertilisation/activation method, cleavage-stage biopsy or species. In addition, differences on epigenetic profiles, coping mechanisms after cell removal and further organ development were present among patterned embryos. Future work is advised to understand the basis of the mechanism(s) driving or driven by cell allocation patterns; particularly its relation with organ development.

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Yu, Xiang. "Wingless signal transduction during Drosophila embryonic development." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624339.

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Desbordes, Sabrina. "The role of the Drosophila glypicans in wingless and hedgehog signalling during embryogenesis." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615868.

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31

Steinel, Martin C. "Flamingo/Starry night in embryonic abdominal sensory axon development of Drosophila /." Connect to thesis, 2008. http://repository.unimelb.edu.au/10187/3144.

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Cleaver, Ondine Beatrice. "Neovascularization of the Xenopus embryo /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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Chan, Siu-yuen. "Effects of prostaglandins on peri-implantation development of mouse embryos /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12730191.

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34

Huang, Bing-Quan. "Isolation and characterization of embryo sacs and their component cells in a synergidless (Plumbago) and a synergid-bearing (Nicotiana) angiosperm /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1991.

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35

Page, Karen Mary. "Mathematical models in embryology : the selection, regulation and speed of formation of patterns." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302119.

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36

Frenk, Mora Silvia Elena. "Embryology in its relation to genetics and evolution : experimental analysis and historical perspectives." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283901.

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37

Molder, Anna. "Computer vision for sequential non-invasive microscopy imaging cytometry with applications in embryology." Thesis, Manchester Metropolitan University, 2016. http://e-space.mmu.ac.uk/618221/.

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Many in vitro cytometric methods requires the sample to be destroyed in the process. Using image analysis of non-invasive microscopy techniques it is possible to monitor samples undisturbed in their natural environment, providing new insights into cell development, morphology and health. As the effect on the sample is minimized, imaging can be sustained for long un-interrupted periods of time, making it possible to study temporal events as well as individual cells over time. These methods are applicable in a number of fields, and are of particular importance in embryological studies, where no sample interference is acceptable. Using long term image capture and digital image cytometry of growing embryos it is possible to perform morphokinetic screening, automated analysis and annotation using proper software tools. By literature reference, one such framework is suggested and the required methods are developed and evaluated. Results are shown in tracking embryos, embryo cell segmentation, analysis of internal cell structures and profiling of cell growth and activity. Two related extensions of the framework into three dimensional embryo analysis and adherent cell monitoring are described.

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Ochora, John. "The embryology, seed coat, and conservation of some Kenyan species of the orchidaceae." Doctoral thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/6154.

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Summary in English.
Bibliography: p. 165-198.
Aspects of embryology, seed morphological features and symbiotic seed germination of the Kenyan orchid species of the subfamily Epidendroideae were examined critically in order to elucidate their development and importance in conservation. The embryology of ca. 70 species was studied by clearing-squash techniques and differential-interference-contrast optics and seeds of ca. 50 species were studied by scanning electron microscopy to determine their variations.

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Johnson, Gabriel Paul. "Early embryology of Ceratopteris richardii and immunocytochemistry of placental transfer cell wall ingrowths /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1597619681&sid=11&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Van, Campenhout Claude. "Etude du rôle du facteur de transcription Evil au cours du développement du rein embryonnaire chez le xénope." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210848.

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Chez les vertébrés, le système excréteur se développe de manière séquentielle sous la forme de trois types de reins différents :le pro-, le méso- et le métanéphros. Le pronéphros des embryons de xénope et de poisson zèbre se développe rapidement et présente une structure simple formée d’un unique néphron, ce qui en fait un excellent modèle d’étude de la néphrogenèse. Au cours du développement, le mésoderme pronéphrique est régionalisé en plusieurs domaines à l’origine des différents composants du néphron partagés par tous les reins des vertébrés :le glomus, les tubules proximaux, le tubule distal et le canal. Cette régionalisation fait appel à des mécanismes moléculaires encore peu connus. Parmi ceux-ci, le facteur de transcription WT1 inhiberait, dans les cellules à l’origine du glomus, l’expression des gènes caractéristiques des tubules proximaux. De plus, la voie de signalisation Notch est requise séquentiellement d’abord pour la formation du glomus et ensuite lors de la différenciation des tubules proximaux.

Le gène Evi1 code pour un facteur de transcription à doigts à zinc notamment exprimé dans le métanéphros des vertébrés supérieurs et jouant un rôle majeur mais mal compris dans le développement. Chez l’embryon de xénope, le gène Evi1 est exprimé dès la fin de la neurulation dans la région ventro-postérieure de l’ébauche pronéphrique à l’origine du tubule distal et du canal. Son expression est inhibée par le facteur de transcription xWT1 et l’activation de la voie de signalisation Notch. Via des expériences de surproduction de la protéine Evi1 sauvage ou d’une fusion Evi1-VP16, fonctionnant de manière antagoniste à la protéine sauvage, nous avons montré que la protéine Evi1 joue un rôle important dans la néphrogenèse précoce en inhibant la formation du glomus et des tubules proximaux dans les cellules à l’origine du segment distal du néphron.

Afin de déterminer l’importance du facteur de transcription xWT1 dans la régulation de l’expression du gène Evi1 ainsi que dans la formation du glomus, des expériences de sous-expression ont été réalisées. Ces expériences montrent que la sous-expression de xWT1 inhibe la formation du glomus mais n’induit cependant pas d’expansion de l’expression du gène Evi1 ni celle d’autres marqueurs du pronéphros, suggérant l’existence d’au moins un autre facteur répresseur exprimé au niveau de la couche médiane du mésoderme pronéphrique.

Ensuite, nous avons comparé les profils de gènes codant notamment pour des protéines spécialisées dans le transport de solutés dans les reins embryonnaires de xénope et de poisson zèbre. Nos résultats montrent que le pronéphros du poisson zèbre, bien que présentant une structure uniforme, peut être subdivisé en quatre différents segments. Ces observations suggèrent que les reins embryonnaires du xénope et du poisson zèbre présentent des organisations similaires.

Dans la dernière partie de ce travail, nous avons entamé l’étude du promoteur du gène CLC-K, codant pour un canal chlore exprimé dans du segment distal du néphron, par la réalisation d’embryons transgéniques de xénope. Les résultats préliminaires obtenus indiquent qu’un fragment de 11kb du promoteur du gène CLC-KB humain est suffisant pour diriger une expression correcte du transgène chez le xénope.
Doctorat en sciences, Spécialisation biologie moléculaire
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41

Kaska, Yakup. "Studies on the embryology, ecology and evolution of sea turtles in the Eastern Mediterranean." Thesis, University of Glasgow, 1998. http://theses.gla.ac.uk/5321/.

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1-) The temperature of sea turtle nests in the Eastern Mediterranean was between 24 and 35 "C and rose by up to 10 "C during incubation. 2-) The mean incubation temperature can be used for estimating the incubation period but provides a poor prediction of sex ratio. 3-) The mean temperature during the middle third of the incubation period was closely correlated with the percent sex ratio. 4-) There was a female dominated sex ratio among the 22 nests and only one loggerhead turtle nest showed less than a 50 % female sex ratio. 5-) There was a consistent temperature difference within the nest with top eggs warmer, bottom eggs cooler and middle ones intermediate. Therefore the majority of hatchlings 11'0111 the top level in nests were females and those from the bottom level were predominantly males. 6-) Temperature differences within the nest also influenced the rate of development; the greater the difference in temperature between top and bottom the longer the time required to complete hatching of all embryos of the nest. The hatching intervals of green turtle nests were shorter than those at loggerhead turtle nests. Temperature variation between top and bottom of nests was low within green turtle nests. In general, a 1 "C temperature difference within the clutch caused a 4 day range in both hatching and emergence of hatchlings. 7-) Since the temperature within the nest and between the nests was so variable, sand air or sea water temperatures gave a poor prediction of the temperature of a nest and therefore the sex ratio. 8-) Although the predation pattern of sea turtle nests varied in relation to nest age, this predation can be reduced by screening the nest with mesh grids.9-) lnundation was one of the main abiotic factors lowering the hatching success on the beaches. Hatching success can be increased by relocating the nests to a safer area on the night of laying 10-) The mean grain sizes of sand ranged from 0.49 to 2.20 phi(

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42

Bassham, Susan Lee. "Molecular embryology of a larvacean urochordate, Oikopleura dioica, and the origin of chordate innovations." Thesis, view abstract or download file of text, 2002. http://wwwlib.umi.com/cr/uoregon/fullcit?p3055666.

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Thesis (Ph. D.)--University of Oregon, 2002.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 125-138). Also available for download via the World Wide Web; free to University of Oregon users.

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43

Xu, Jiasen. "A study of embryotrophic mechanism of human oviductal cells on mouse embryo development in vitro." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22926197.

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44

Katerji, Suhair. "Etude de la dysmorphose craniofaciale chez le rat Dumbo." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210286.

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Le rat Dumbo présente un aspect malformatif évoquant certains syndromes crânio-faciaux humains. La compréhension du phénotype Dumbo pourrait expliquer les événements cellulaires et moléculaires à l’origine de ces syndromes. Le données recueillies chez le rat Dumbo et comparées à celles du rat Wistar sont susceptibles de constituer de précieuses informations éventuellement transposables à l’espèce humaine.

La première étape de cette étude a consisté en des analyses morphologiques et morphométriques afin de vérifier les perturbations morphologiques communes entre les rats Dumbo et les syndromes malformatifs humains :la brièveté des os zygomatique, maxillaire, mandibulaire et la position basse des oreilles. Ces analyses ont été réalisées sur les squelettes embryonnaires âgés de 16 jours à 21 jours de rats Dumbo et Wistar à l’aide d’une coloration in toto au Bleu Alcian – Alizarine. La deuxième étape de cette étude consistait en une analyse cytogénétique. Pour ce faire, nous avons établi le caryotype du rat Dumbo et nous l’avons comparé avec le caryotype du rat Wistar. L’étape suivante fut de procéder à l’analyse histologique des malformations crânio-faciales chez le rat Dumbo en observant la chondrogenèse pendant la morphogenèse crânio-faciale. Enfin, l’examen de l’expression des gènes Msx1 sens (S) ,Msx1 antisens (AS) et Dlx1 dans l’extrémité céphalique des rats Dumbo a été réalisé par les techniques de RT–PCR (Reverse Transcription Polymerase Chain Reaction method). Des estimations semi-quantitatives ont été validées en utilisant des dilutions ADNc du rat Wistar. Des densitométries de la densité d’amplicons fluorescence ont été réalisées à l’aide du logiciel VilberLourmat Bio1D software.

Les résultats obtenus ont permis de caractériser de manière précise les malformations crânio-faciales chez le rat Dumbo.

1-\
Doctorat en Sciences biomédicales et pharmaceutiques
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45

Banks, Glen B. "The role of synapse formation on motoneuron survival during embryonic development /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17453.pdf.

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46

Solomin, Ludmila. "Nuclear hormone receptor signaling in the developing CNS : studies on the retinoid receptors RAR and RXR, and the orphan receptors NURR1, NOR1 and NGFI-B /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3663-3/.

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47

Fuku, Eiji. "Studies on the preservation of mammalian embryos in the supercooled state." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60523.

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Firstly, exposure of compacted morulae (CM) and early blastocysts (EB) to methanol (M) or glycerol (G) for 1 h at room temperature followed by culture in standard culture medium showed that the embryos tolerated up to 12 to 24% methanol or 24 to 48% glycerol. Next, the effects of stage of embryo (CM vs EB), preservation temperature and concentration of 1:1 M:G on embryo survival were tested. EB survived longer than CM under all conditions. Increased concentrations of cryoprotectants (M and G) increased the survival of supercooled embryos, but survival was decreased with the storage temperature. Replacing G with propanediol (P) significantly increased blastocyst survival at lower temperatures.
Exposure for 1 h to $>$ 0.6 M of sucrose or trehalose at room temperature suppressed growth in culture, but dehydration in up to 0.4M sucrose before supercooling (in M:P) increased survival at $-$5 or $-$10$ sp circ$C, survival increasing with dehydration.
Finally, demi-embryos and intact embryos were cultured to the blastocyst stage, stored at $-$5$ sp circ$ for 48 h, then cultured for 24 h and transferred into pseudopregnant recipients.

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48

Bates, Alan William. "Situs inversus and lateral asymmetry in larvae of the toad Xenopus laevis." Thesis, Queen Mary, University of London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481544.

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Uy, Gary D. "Studies on the control of diploid trophoblast growth in the mouse." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365366.

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Chia, Gloryn Le Bin. "Investigating the role of Oct4 during lineage specification in the physiological context of mouse embryonic development." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607990.

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Dissertations / Theses on the topic 'Embryology'

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