Thesis (M.A.)--University of Hong Kong, 1988. / Also available in print.

Thesis (doctoral)--University of Hong Kong, 1997.

<p>Masterarbetet består av en skriftlig deloch en gestaltande del. </p>

Abstract The Z-disk is a sophisticated structure that connects adjacent sarcomeres in striated muscle myofibrils. α-Actinin provides strength to the Z-disks by crosslinking the actin filaments of adjacent sarcomeres. α-Actinin is an antiparallel homodimer, composed of an N-terminal actin binding domain (ABD), the central rod domain, and two pairs of C-terminal EF-hands. The PDZ-LIM domain proteins interact with α-actinin at the Z-disk. Of these proteins, only the actinin-associated LIM protein (ALP), Z-band alternatively spliced PDZ-containing protein (ZASP/Cypher) and C-terminal LIM protein (CLP36) have a ZASP/Cypher-like (ZM) motif consisting of 26-27 conserved residues in the internal region between the PDZ and LIM domains. The aim of this work was to understand the molecular interplay between the ZM-motif containing members of the PDZ-LIM proteins and α-actinin. To unveil the biological relevance of the interaction between the PDZ-LIM proteins and α-actinin, naturally occurring human ZASP/Cypher mutations were analyzed. Two interaction sites were found between ALP, CLP36 and α-actinin using recombinant purified proteins in surface plasmon resonance (SPR) analysis. The PDZ domain of ALP and CLP36 recognized the C-terminus of α-actinin, whereas the internal regions bound to the rod domain. Further characterization showed that the ALP internal region adopts and extended conformation when interacting with α-actinin and that the ZM-motif partly mediated the interaction, but did not define the entire interaction area. ZASP/Cypher also interacted and competed with ALP in binding to the rod domain. The internal fragments containing the ZM-motif were important for co-localization of ALP and ZASP/Cypher with α-actinin at the Z-disks and on stress fibers. The absence of ALP and ZASP/Cypher in focal contacts indicates that other interacting molecules, for instance vinculin and integrin, may compete in binding to the rod in these areas or additional proteins are required in targeting to these locations. The co-localization of the ZASP/Cypher with α-actinin could be released by disrupting the stress fibers leading to an accumulation of α-actinin in the cell periphery, whereas ZASP/Cypher was not in these areas. This suggests that an intact cytoskeleton is important for ZASP/Cypher interaction with α-actinin. Earlier studies have shown that mutations in the ZASP/Cypher internal region are associated with muscular diseases. These mutations, however, did not affect ZASP/Cypher co-localization with α-actinin or the stability of ZASP/Cypher proteins. The Z-disk possesses a stretch sensor, which is involved in triggering hypertrophic growth as a compensatory mechanism to increased workloads. α-Actinin is a docking site of molecules that are involved in hypertrophic signaling cascades mediated by calsarcin-calcineurin and protein kinase C (PKC) isoforms. The internal interaction site may be involved in targeting PKCs, which bind to the LIM domains of ZASP/Cypher, to the Z-disks. The similar location of the internal interaction site with calsarcin on the rod suggests that ZASP/Cypher, ALP and CLP36 may regulate calsarcin-mediated hypertrophic signaling.

Lhx genes are a sub-family of Hox genes that play important roles in animal development. In Caenorhabditis elegans there are seven Lhx genes, including the founding family member lin-11. The lin-11 gene is necessary for the specification of neuronal and reproductive tissues. My thesis work has involved understanding the mechanism of lin-11 regulation and its function in these tissues. To this end, I addressed two distinct but complementary questions, one of which focused on how transcriptional regulation of lin-11 occurs and the second on the role of LIN-11 protein domains/regions. My work on the transcriptional regulation has uncovered important roles of two of the largest lin-11 introns, intron 3 and intron 7. These introns promote lin-11 expression in non-overlapping sets of amphid neurons. Based on gene expression patterns and behavioural assays, intron 3 is capable of restoring lin-11 function in lin-11(n389 ) null mutant allele. Comparison of intron 3-driven reporter expression in the neuronal cell types between C. elegans and C. briggsae has revealed cis and trans evolutionary changes in lin-11 regulation between the two species. Functional dissection of the introns in C. elegans has led to the identification of three distinct non-overlapping enhancers, each specific for a single amphid neuron, i.e., RIC, AIZ, and AVG. I have also identified four transcription factors, SKN-1, CEH-6, CRH-1, and CES-1, that act through these enhancers to regulate neuronal expression of lin-11. Furthermore, I have characterized the function of the LIM domains and a proline-rich (PRR) C-terminus region of LIN-11 in the specification of neuronal and reproductive tissues. My work shows that while the LIM domains are required for LIN-11 function in these tissues, the PRR region is dispensable. I have also examined the functional conservation of lin-11 domains using two other Lhx genes, Drosophila melanogaster (dLim1) and Mus musculus (Lhx1 ), and found that both of these genes were able to rescue lin-11 defects. Together, my work has significantly advanced our understanding of transcriptional regulation of lin-11, the importance of LIM domains in tissue formation, and functional conservation of Lhx genes across phyla. / Thesis / Doctor of Philosophy (PhD)

The quasi two-day wave (QTDW), a prominent feature of the mesosphere mainly around solstices, is simulated with the COMMA-LIM Model (Cologne Model of the Middle Atmosphere - Leipzig Institute for Meteorology). The calculations are made approximately one month after the summer solstice in the Northern Hemisphere when the QTDW reaches its maximum in the mesosphere and lower thermosphere. The results show that the QTDW produces a moderate westward forcing of the zonally averaged flow and a poleward driving of the residual mean meridional circulation. / Die Quasi Zwei-Tage Welle (QTDW), eine deutliche Erscheinung in der Mesosphäre kurz nach dem Sommer Solstitium, wird mit dem COMMA-LIM Modell (Cologne Model of the Middle Atmosphere - Leipzig Institute for Meteorology) simuliert. Die Zwei-Tage Welle wurde unter Juli-Bedingungen an der unteren Modellgrenze angeregt, zu der Zeit, zu der sie ihr Maximum in der Mesosphäre und unteren Thermosphäre erreicht. Die Ergebnisse zeigen eine sich westwärts ausbreitende Welle, die auf den Grundstrom eine moderate Beschleunigung nach Westen ausübt. Die residuelle mittlere Meridional Zirkulation erfährt dadurch eine zum Pol gerichtete Triebkraft.

No description available.

Le cancer du sein était au premier rang des cancers chez la femme en termes d'incidence et de mortalité en 2008 (GLOBOCAN 2012, IARC). A l'origine de cette mortalité on observe notamment le développement de résistances aux chimiothérapies conventionnelles mais aussi le développement des métastases qui sont responsables de 90% des décès des patientes. Il est donc indispensable d'étendre l'arsenal thérapeutique à la disposition des cliniciens avec de nouvelles molécules actives sur les formes de cancers résistants aux chimiothérapies et ciblant le processus métastatique.Au sein de notre équipe nous avons identifié un nouvel inhibiteur de la LIM Kinase (LIMK) baptisé « Pyr1 ». La LIMK est responsable de la régulation de la dynamique des microtubules et des microfilaments d'actine. Dans un premier article (Prudent et al., Cancer Research, 2012) nous avons montré que Pyr1 avait une activité anti-mitotique et anti-migratoire dans un modèle cellulaire de cancer de l'utérus. De plus une analyse pilote a montré que Pyr1 était efficace dans un modèle murin de leucémie où il augmente la survie des souris. Étant donné que la LIMK est surexprimée dans les cancers du sein et qu'une des conséquences cellulaires d'un traitement par Pyr1 est une stabilisation des microtubules, comme le fait le paclitaxel couramment utilisé pour le traitement des formes invasives de ces cancers , l'objectif de ma thèse a été d'étudier l'efficacité thérapeutique de Pyr1 sur des modèles cellulaires et murins de cancer du sein, et notamment sur les cancers résistants au paclitaxel.Nous avons montré que Pyr1 ralentissait la croissance des tumeurs primaires et réduisait leur taille. Pyr1 est bien toléré et l'effet anti-tumoral est également observé sur des modèles résistants au paclitaxel. Nous avons ensuite étudié l'effet de Pyr1 sur la migration et l'invasion des cellules tumorales en utilisant notamment la microscopie intra-vitale. Nous avons observé que, bien qu'il ne diminue pas la vitesse de migration des cellules tumorales, Pyr1 entraine in vivo un changement morphologique important. Enfin, Pyr1 n'empêche pas la dispersion métastatique mais il prévient de manière efficace la croissance des métastases.Nous en avons conclu que Pyr1 est une molécule intéressante pour le traitement des cancers du sein résistants aux chimiothérapies conventionnelles et également sur le traitement des métastases. / Breast cancer is the most common diagnosed cancer in women worldwide with an increase of 20% and 14% in terms of incidence and mortality, respectively, in 2008 (GLOBOCAN, 2012). This increase is mainly due to the lack of therapeutics that target the development of metastasis responsible for 90% of cancer death. Moreover, the development of resistance to available chemotherapies limits their effectiveness. It's an urgent need to find new drugs that target the metastatic process and are efficient on resistant cancers.Our team has identified a new LIM Kinase (LIMK) inhibitor called “Pyr1”. LIM Kinases are implicated in the dynamic regulation of the actin and microtubule cytoskeleton. We previously published data showing that Pyr1 has an anti-mitotic and anti-migratory activity on a cervical cancer cell line. Moreover, a pilot in vivo study has shown that Pyr1 was efficient in a leukemia mouse model where it increases the lifespan of treated compared to control mice (Prudent et al., 2012).LIM Kinases have been shown to be overexpressed in breast cancer. Moreover the chemotherapeutical agents currently used for this kind of cancer belong to the class of taxanes (such as paclitaxel). Taxanes are cytotoxic compound that directly binds to microtubules and stabilizes them. Since Pyr1 treatment also results in microtubules stabilization, with a complete different mechanism of action, we have decided to investigate the anti-cancer effect of Pyr1 on breast cancer cell lines and xenografts, including paclitaxel resistant models.We showed that Pyr1 decreases primary tumor growth and reduces their size. Pyr1 is well tolerated and the anti-tumor effect is also observed on paclitaxel resistant models. We then studied Pyr1 effects on migration and invasion in vitro and in vivo. Intravital imaging of tumors showed that, whereas Pyr1 didn't slow down tumor cell migration, it induced a cell morphological change. Finally, Pyr1 does not affect metastasis spreading but prevents their growth.These results indicate that LIMK inhibitors, such as Pyr1, may represent a pharmacological alternative for taxanes resistant tumors. Moreover, they could be potent agents to reduce the size of metastasis.

Orientador: Marcelo Menossi Teixeira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T17:06:41Z (GMT). No. of bitstreams: 1 Baldacin_MariaGrazielaZagattoKrug_D.pdf: 4445527 bytes, checksum: 9730d155ac6ebf7d24d427feb43a2acb (MD5) Previous issue date: 2010 / Resumo: A toxidez por alumínio (Al3+) é o principal fator limitante da produção agrícola em grandes áreas do Brasil e do mundo. Sabe-se que a defesa das plantas a este elemento é controlada por múltiplos genes. A caracterização de genes cuja expressão é induzida pelo Al contribui para compreender as defesas ativadas pelas plantas. Neste trabalho identificou-se um cDNA de milho expresso em raízes através da técnica de mRNA differential display. Este cDNA codifica uma seqüência que contem dois domínios LIM, separados por um espaçador de 40-50 resíduos, sendo denominado Zmlim-1. O objetivo deste trabalho é a caracterização deste gene e o seu papel na tolerância ao Al em milho. Em estudos de expressão verificou-se que o gene Zmlim- 1 é induzido por Al e sua expressão é maior na linhagem tolerante, Cat100-6, quando comparado com a linhagem sensível S1587-17. O direcionamento da proteína ZMLIM-1 foi observado em epitélios de cebola bombardeados com a construção fusionada à proteína GFP (green fluorescent protein). A expressão transiente revelou que esta proteína está localizada no citoplasma e no núcleo. A hibridização in situ demonstrou que Zmlim-1 é expresso na maioria das células do ápice de raiz de milho. O sistema de duplo híbrido de levedura permitiu identificar três proteínas que interagem com a proteína ZMLIM-1: duas proteínas da subunidade ribossomal e uma proteína da família OMT envolvida na biossíntese de lignina. Plantas transgênicas silenciando este gene forneceram evidências de que o gene Zmlim-1 pode influenciar a anatomia da raiz e a quantidade de lignina. Este é o primeiro relato de interação OMT com proteínas de domínio LIM, sugerindo um envolvimento desta proteína com a biossíntese de lignina. Plantas transgênicas submetidas ao estresse por Al3+ não apresentaram diferenças com relação às plantas controle não transformadas / Abstract: Aluminum (Al) toxicity is the main factor limiting agricultural production in large areas in Brazil and in the world. It is known that plant defenses against this element are controlled by multiple genes. The characterization of genes whose expression is induced by Al contributes to the understanding of the defenses activated by plants. In this work we identified a cDNA expressed in maize roots using mRNA differential display. This cDNA encodes a sequence that contains two LIM domains separated by a spacer of 40-50 residues, being named Zmlim-1. The purpose of this study was the characterization of this gene and its involvement in Al tolerance in maize. In expression studies it was found that the Zmlim-1 gene was induced by Al and its expression was higher in the tolerant line, Cat100-6 when compared with the sensitive line S1587-17. The subcellular localization of the protein ZMLIM-1 was observed in onion epithelial cells bombarded with a ZMLIM-1::GFP (green fluorescent protein) fusion. The assay of transient expression revealed that this protein is localized in cytoplasm and nucleus. In situ hybridization showed that Zmlim-1 is expressed in most cells of the root apex of maize. The yeast two hybrid system identified three proteins that interact with ZMLIM-1 protein: tworibosomal subunit proteins and a protein from the OMT family involved in lignin biosynthesis. Transgenic plants silenced for this gene have provided evidence that Zmlim-1 gene can influence the anatomy of the root and the amount of lignin in the plants. This is the first report of OMT interaction with LIM domain proteins, suggesting an involvement of this protein with lignin biosynthesis. Transgenic plants subjected to Al3+ stress did not show differences when compared to control, untransformed plants / Doutorado / Genetica Vegetal e Melhoramento / Doutor em Genetica e Biologia Molecular

The final work of master studies reviews various industrial robots constructions and parameters, from which they are characterized. Robotics systems and control of flexible production have been discussed in here. Various robots’ drives and their control advantages and disadvantages are analyzed. In the practical part original robot global movement platform is suggested and algorithm of two flexible production bays handling is created. Static characteristics of linear drive used in platform are calculated. Using software package “Matlab Simulink” model of symmetrical linear induction motor (LIM) is created and dynamic characteristics are gained. Concluding part presents inferences and suggestions.