Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: plant metal homeostasis; P1B ATPases1. Includes bibliographical references (p. 45-53).

Thesis (Ph. D.)--University of Cape Town, 2003. / Includes bibliographical references (leaves 284-287). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Sept. 24, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physiology, Cell and Developmental Biology, Biological Sciences, University of Alberta." Includes bibliographical references.

Thesis (Ph.D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 11, 2009) Includes bibliographical references.

Thesis (D.Phil (Zoologyy ))--University of Pretoria, 2002. / Includes abstract in English. Includes bibliographical references.

Thesis (Ph. D.)--University of Cape Town, 2003. / Includes bibliographical references (leaves 284-287).

Thesis (M.S.)--Ohio University, November, 2006. / Title from PDF t.p. Includes bibliographical references.

Chez les plantes, alors qu'il est clair que l'homéostasie des différents nutriments est fortement dépendante les uns des autres, ils sont généralement étudiés indépendamment les uns des autres. Étant donné la rareté des études antérieures évaluant la signification biologique de l'interaction de l'homéostasie des nutriments minéraux, on en sait très peu sur la base génétique et moléculaire de ces interactions. Au cours de ma thèse, nous avons progressé de manière significative vers une compréhension plus intégrative du problème et identifié les bases moléculaires et génétiques d'une interaction nutritive très importante et conservée: l'interaction du zinc et du phosphate, dans laquelle les gènes PHO1;H3 et Lyso PhosphatidylCholine (PC) AcylTransferase 1 (LPCAT1) jouent des rôles centraux. En combinant des approches de biologie systémique et de biologie fonctionnelle, nous avons identifié le module fonctionnel (quatre facteurs transcriptions) qui régule l'expression de PHO1; H3 en condition de carence en Zn. Suite à une étude de génétique d’association (GWAS) nous avons découvert un nouveau rôle du gène LPCAT1 dans l’accumulation du phosphate en conditions de carence en Zn, Ensuite, nous avons déterminé une voie moléculaire complète contrôlant l'expression de ce gène. Ce travail nous permis de révéler un lien fondamental entre le métabolisme des phospholipides et l'interaction homéostasie Pi-Zn, et de proposer un nouveau rôle pour Lyso-PC et PC dans le contrôle de l'interaction homéostasie macro- et micronutriments chez les plantes. Les résultats obtenus offrent une nouvelle perspective pour élabore des nouvelles stratégies pour améliorer l’accumulation de Pi dans les plantes via la modulation de la voie de signalisation de la carence en Zn. / In plants, while it is clear the homeostasis of different nutrients is highly dependent on each other, they are usually studied independent of each other. Given the paucity of past studies assessing the biological significance of mineral nutrient homeostasis interaction, very little is known about the genetic and molecular basis of such interactions. During my thesis, we made significant progress in going towards a more integrative comprehension of the problem and identify the molecular and genetic bases for a highly important and conserved nutrients interaction: the interaction of zinc and phosphate. First, using the phosphate transporter PHO1;H3 as entry molecular point, and by combining system biology and functional genomics approaches we have identified the functional module (four transcription factors) that regulates the expression and activity of PHO1;H3 under Zn deficiency leading to control Pi accumulation in shoots. Second, following our discovery of Lyso PhosphatidylCholine (PC) AcylTransferase 1 (LPCAT1) using genome-wide association studies (GWAS), we determined complete molecular pathway controlling the expression of this gene. We further uncovered a fundamental link between phospholipid metabolism and Pi-Zn homeostasis interaction via LPCAT1, which lays the foundations to explore a new role for Lyso-PC and PC in control of macro- and micronutrients homeostasis interaction. Taken together, our discoveries offer a new perspective on how to improve Pi content in plants, as our findings suggests that modulating the Zn-deficiency signalling pathway might be a good and simple approach for that.

Orientador: Débora Simões de Almeida Colombari / Banca: Colin Sumners / Banca: Cássia Marta de Toledo Bermagaschi / Banca: Vagner Roberto Antunes / Banca: Lucila Leico Kagohara Elias / Resumo: O sistema nervoso central (SNC) tem um papel fundamental na regulação de mecanismos que controlam a osmolaridade dos líquidos corporais. O núcleo do trato solitário (NTS) é o sítio primário das aferências cardiovasculares e de osmorreceptores periféricos e se projeta à áreas prosencefálicas envolvidas com a regulação cardiovascular e do equilíbrio hidroeletrolítico. Demonstramos anteriormente que animais com lesão da porção comissural do NTS (commNTS) tem maior ingestão de água, natriurese e resposta pressora frente a sobrecarga intragástrica (ig) de NaCl 2 M. Os mecanismos responsáveis por estas alterações ainda não foram determinados. Uma vez que o estímulo com NaCl 2 M ig (2 ml) ativa osmorreceptores centrais e periféricos, não sabemos até o momento os efeitos da lesão do commNTS sobre as respostas observadas após a estimulação específica de osmorreceptores periféricos, que pode ser feita com NaCl 0,6 M ig. (2 ml). Desta forma os nossos objetivos foram: a) estudar os mecanismos que medeiam o aumento da pressão arterial e da natriurese após a sobrecarga de NaCl 2 M em animais com lesão do commNTS; b) verificar as alterações na expressão da proteína c-Fos após NaCl 2 M ig em ratos com lesão fictícia (sham) ou lesão do commNTS; c) verificar as alterações na expressão gênica no PVN após NaCl 2 M ig, d) estudar os efeitos na pressão arterial, na ingestão de água e na excreção renal subseqüentes a administração de NaCl 0,6 M ig, bem como os mecanismos responsáveis pelas alterações, em ratos com lesão fictícia (sham) ou lesão do commNTS; e) verificar as alterações na expressão da proteína c-Fos após NaCl 0,6 M ig em ratos com lesão fictícia (sham) ou lesão do commNTS. Ratos Holtzman (280-320 g) foram utilizados. A lesão eletrolítica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The central nervous system has an important role controlling the mechanisms involved in the regulation of body fluid osmolality. The nucleus of the solitary tract (NTS) is the primary site of cardiovascular and peripheral osmoreceptors afferents and projects to prosencephalic areas involved in hydroelectrolytic balance and cardiovascular regulation. We have demonstrated that commissural NTS (commNTS) lesioned rats had an increase in arterial pressure and a greater increase in water intake and natriuresis after 2 M NaCl intragastric (ig) load. The mechanisms involved in these responses are not known. Since 2 M NaCl ig (2 ml) activates central and peripheral osmoreceptors, it is not known the effects of the commNTS lesion on the responses induced only by the activation of the peripheral osmoreceptors, which can be done by 0.6 M NaCl (2 ml) ig. Thus, the aims of this study were: a) to study the mechanisms involved in the increase of the arterial pressure and natriuresis in commNTS lesioned rats after 2 M NaCl ig; b) to verify the changes in c-Fos expression after 2 M NaCl ig in sham and commNTS lesioned rats; c) to verify the changes in gene expression in PVN after 2 M NaCl ig in naïve rats; d) to study the effects on arterial pressure, water intake and renal excretion after 0.6 M NaCl, as well as, the mechanisms involved in these responses, in sham and in commNTS lesioned rats; e) to verify the changes in c-Fos expression after 0.6 M NaCl ig in sham and commNTS lesioned rats. Male Holtzman rats (280-320 g) were used. Electrolytic lesion of the commNTS and all experiments were be performed in chronic period of lesion (14 to 21 days. For the lesion, a partial craniotomy of the occipital bone was performed, and the dorsal surface of the brainstem was exposed. The electrolytic lesion was performed using... (Complete abstract click electronic access below) / Doutor

The intestinal barrier represents a complex environment, composed of different physical barriers and immune cells, which act to prevent the entrance of potentially harmful enteric pathogens and to maintain gut tolerance to food antigens and commensal bacteria. Thus, cross-talk between the different components of the intestinal barrier such as the mucus layer, dendritic cells (DC) and intestinal intraepithelial lymphocytes (IELs) may be important in maintenance of gut homeostasis. This thesis investigates how different components of the intestinal barrier regulate immune responses in the gut. Thus, expression of the transmembrane receptor integrin αvβ8 on DCs is shown to be required for the development of a specific IEL subset marked by expression of CD4 and CD8αα, suggesting that intestinal DC play important roles in regulating the IEL compartment. Moreover, considering that intestinal DCs are likely in close contact with intestinal mucus, it was hypothesized that interactions between DCs and mucins, the predominant proteins that form the mucus layer, may modulate DC function. To test this hypothesis, intestinal mucin was purified and used to treat human monocyte-derived DCs. It was found that that expression of the chemokine IL-8 and co-stimulatory DC markers CD86 and CD83 are significantly upregulated on human DCs in the presence of intestinal mucins. Additionally, IL-8 produced by mucin-treated DCs is able to recruit neutrophil-like cells in transmigration assays. These effects were not due to mucin sample contaminants such as LPS, DNA or contaminant proteins. Instead, mucin glycans seem to be important for the induction of these effects on moDCs. Thus, in contrast to recent published results, intestinal mucins appear capable of inducing important pro-inflammatory functions in DC. To investigate whether mucins modulated DCs found in the intestinal environment, intestinal mucins were used to treat murine intestinal DCs, and gene changes explored using microarray analysis. It was found that, amongst several genes modulated in intestinal DC, up-regulation of the mucosal cytokine IL-22 was induced by intestinal mucin. Therefore, interactions between different components of the intestinal barrier might be crucial for maintaining gut homeostasis. Understanding how different components of the intestinal barrier system work together to maintain homoeostasis may identify pathways that can be targeted to restore this balance in inflammatory disorders such as inflammatory bowel disease.