Diss. (sammanfattning) Umeå : University, 2005. / Härtill 5 uppsatser. På omsl. felaktigt: N.S. 954.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Resumo: O Mycobacterium tuberculosis, principal agente da tuberculose (TB), é responsável pela morte anual de dois a três milhões de pessoas no mundo e por prejuízos econômicos globais de aproximadamente 12 bilhões de dólares ao ano. Estima-se que 1/3 da população mundial esteja infectada com o bacilo na forma latente. Apesar disso, nenhuma nova droga específica contra o M. tuberculosis foi desenvolvida desde 1960. O presente trabalho objetivou a investigação do potencial anti-M. tuberculosis intra e extracelular juntamente com a citotoxicidade de 66 compostos envolvendo diferentes classes de ligantes como tiossemicarbazonas, semicarbazonas, hidrazonas, diiminas, fosfinas e bases de Schiff, juntamente com dois diferentes metais (vanádio e rutênio) formando diferentes e inéditos complexos. Para as diferentes análises biológicas in vitro, 3 técnicas já padronizadas foram utilizadas para a detecção da Concentração Inibitória Mínima (CIM), da Citotoxicidade (IC50) e da Atividade Intracelular. Dos 66 compostos analisados neste trabalho, 7 complexos contendo o rutênio, cis-[RuCl2(NO)(BPA)] (G1), cis- [Ru(pic)(dppe)2]PF6 (G6), [Ru(pic)(dppb)(bipy)]PF6 (G7), [Ru(pic)(dppb)(Mebipy)] PF6 (G8), [Ru(pic)(dppb)(Cl-bipy)]PF6 (G9), [Ru(pic)(dppb)(fen)] (G12), cis-[RuCl2(dppb)(bipy)] (G14), foram qualificados como potenciais agentes anti- TB, porque apresentaram atividade inibitória melhor do que algumas drogas comumente utilizadas no tratamento da tuberculose, baixa citotoxicidade e alta atividade inibitória intracelular. / Abstract: The Mycobacterium tuberculosis, the major agent of tuberculosis (TB), is responsible for approximately 2-3 million deaths annually, with a global economic injury of approximately $12 billion per year. It is estimated that 1/3 of the worldwide population are infected with the latent form bacilli. Although, no new specific drug against M. tuberculosis was developed since 1960. The objective of this study was the investigation of intra and extracellular anti-M. tuberculosis activity and cytotoxicity of 66 compounds involving different class of ligants as thiosemicarbazones, semicarbazones, hydrazones, diimines, phosphines and Schiff bases with two different metals (vanadium and ruthenium) resulting different and unknown complexes. For the different biologicals in vitro analyses, three standardized techniques had been used for the detection of the Minimal Inhibitory Concentration (MIC), Cytotoxicity (IC50) and Intracellular Activity. Of 66 compounds analyzed in this study, 7 complexes containing the ruthenium, cis-[RuCl2(NO)(BPA)] (G1), cis-[Ru(pic)(dppe)2]PF6 (G6), [Ru(pic)(dppb)(bipy)]PF6 (G7), [Ru(pic)(dppb)(Me-bipy)]PF6 (G8), [Ru(pic)(dppb)(Cl-bipy)]PF6 (G9), [Ru(pic)(dppb)(fen)] (G12), cis- [RuCl2(dppb)(bipy)] (G14), were qualified as potential anti-TB agents, because they presented inhibitory activity better than some drugs commonly used in the TB treatment, low cytotoxicity and high intracellular inhibitory activity. / Orientador: Clarice Queico Fujimura Leite / Coorientador: Daisy Nakamura Sato / Banca: Rosemeire Cristina Linhari Rodrigues Pietro / Banca: Mario Hiroyuki Hirata / Mestre

No presente estudo, analisamos a regulação das etapas iniciais da ação insulínica através de imunoprecipitação e imunobloting do tecido hipotalâmico, hepático, adiposo e músculo esquelético de ratos idosos tratados cronicamente com melatonina. O tratamento crônico com melatonina induziu aumento da sensibilidade à insulina acompanhada de regulação positiva das etapas iniciais da ação do hormônio em hipotálamo, fígado, músculo esquelético e tecido adiposo de ratos com 13 meses de idade. Os efeitos da ação da melatonina sobre a sinalização insulínica também ocorreu de forma tecido-específica, de maneira semelhante aos efeitos pleiotrópicos da insulina. Nosso estudo reafirma o papel da melatonina como um fator regulador da ação insulínica e permitem a conclusão de que a reposição desse hormônio pode contribuir com a reversão da resistência à insulina e redução do peso corporal que acompanha o processo normal de envelhecimento. / Melatonin can negate several morphological and metabolic aged-induced changes. Although, this has been known for some time, the mechanism underlying melatonins actions are unclear. As suggested by some studies, a putative interaction between insulin and melatonin could be involved. In the present study, we have examined the regulation of the insulin signaling pathways by using immunoprecipitation and immunoblotting in hypothalamus, liver, adipose tissue and skeletal muscle of aged rats chronically treated with melatonin. Melatonin treatment promoted increase in insulin sensitivity and a reduction of visceral fat. These modifications were accompanied by the increased phosphorylation of insulin signaling downstream compounds associated with food ingestion in hypothalamus, glucose homeostasis in liver and adipose tissue (e.g. IRS-1) and mitogenic action on insulin in skeletal muscle (e.g. ERK-1/2). These results indicate that, in aged rats, melatonin regulates insulin signaling downstream components in a tissue-specific manner.

RALF é um peptídeo hormonal de aproximadamente 5kDa presente em diferentes espécies do reino vegetal regulando negativamente a expansão celular. AtRALF1 é uma isoforma específica de raiz das 37 presentes em Arabidopsis thaliana que regula negativamente o crescimento de raízes seguido de uma mobilização de Ca+2 intracelular e inibição na secreção de prótons (H+). Neste trabalho foi caraterizado a localização e tráfego intracelular do peptídeo AtRALF1. / RALF is a 5kDa peptide hormone ubiquitous in different species of the plant kingdom that regulates cell expansion. AtRALF1 is a root-specific isoform of 37 present in Arabidopsis thaliana that negatively regulates root growth by intracellular calcium mobilization and inhibition of proton secretion (H+). In this work was studied the localization and intracellular trafficking of the AtRALF1 peptide.

The ubiquitously expressed plasma membrane Na⁺/H⁺ exchanger isoform 1 (NHE1) plays an important role in directed cell migration in non-neuronal cells, an effect which requires both the ion translocation and actin cytoskeleton anchoring functions of the protein. In the present study, an analogous role for NHE1 as a modulator of neurite outgrowth was evaluated in vitro utilizing NGF-differentiated PC12 cells as well as mouse neocortical neurons in primary culture. Examined at 3 d.i.v., endogenous NHE1 was found to be expressed in growth cones, where it gave rise to an elevated intracellular pH in actively-extending neurites. Application of the NHE inhibitor cariporide at an NHE1-selective concentration (1 μM) resulted in reductions in neurite extension and elaboration while application of 100 μM cariporide, to inhibit all known plasmalemmal NHE isoforms, failed to exert additional inhibitory effects, suggesting a dominant role for the NHE1 isoform in modulating neurite outgrowth. In addition, whereas transient overexpression of full-length NHE1 enhanced neurite outgrowth in a cariporide-sensitive manner in both NGF-differentiated PC12 cells and WT neocortical neurons, neurite outgrowth was reduced in NGF-differentiated PC12 cells overexpressing NHE1 mutants deficient in either ion translocation activity or actin cytoskeleton anchoring, suggesting that both functional domains of NHE1 are important for modulating neurite elaboration. A role for NHE1 in modulating neurite outgrowth was confirmed in neocortical neurons obtained from NHE1-/- mice which displayed reduced neurite outgrowth when compared to neurons obtained from their NHE1⁺/⁺ littermates. Further, neurite outgrowth in NHE1-/- neurons was rescued by transient overexpression of full-length NHE1 but not with mutant NHE1 constructs again suggesting that both functional domains of NHE1 are important for modulating neurite outgrowth. Finally, the growth promoting effects of netrin-1 but not BDNF or IGF-1 were abolished by cariporide in WT neocortical neurons and while both BDNF and IGF-1 were able to promote neurite outgrowth in NHE1-/- neurons, netrin-1 was unable to elicit this effect. Taken together, these results indicate that NHE1 is a permissive regulator of early neurite morphogenesis and also plays a novel role in netrin-1-stimulated neurite outgrowth. / Medicine, Faculty of / Graduate

Abstract Vision is capable of providing an animal with a wealth of information very fast. Visually guided behaviours are numerous, ranging from foraging to navigation. Vision can be quite reliable in bright light, but the signals produced by the photoreceptors become progressively more unreliable with falling light intensities. In this thesis the usefulness of a novel virtual reality-based environment for insect vision research is reviewed, and the low-light vision of the American cockroach, Periplaneta americana, is assessed using the optomotor behavioural paradigm and intracellular photoreceptor recordings. The optomotor reaction is visual behaviour where an animal responds to a rotation of its environment by following the movement of its surroundings with its eyes or - like insects - by rotating its body in the direction of the movement. Placing the cockroach on a trackball in the middle of the virtual reality apparatus and projecting a rotating pattern of vertical stripes around it invariably causes an optomotor reaction if the cockroach is able to see the moving pattern. Presenting the cockroaches with the stimulus pattern at different low light levels and observing their abilities to follow the movement reveal the lowest light intensity at which they are able to use vision in guiding their behaviour. The compound eye photoreceptor signals at this behavioural threshold consist of singlephoton absorption events called ‘bumps’ at the extremely low rate of one bump every ten seconds. Furthermore, the role of the simple eyes or ocelli in the low-light vision of the cockroach is studied in the virtual reality by covering the compound eyes, the ocelli, or both. The ocelli seem to measure the light intensity and communicate this information to the compound eyes, and also have a direct effect on the general activity level of the cockroach.

Amyotrophic Lateral Sclerosis (ALS) is a rare and fatal neurodegenerative disorder resulting in the loss of motor neurons from the spinal cord and frontal cortex. The patterns of neurodegeneration, affected regions, age of onset, and time course of disease progression are all highly variable between and within variants of the disease. Familial ALS (fALS), inherited versions of ALS due to genetic changes, accounts for between 5-20% of all ALS cases, while the rest are sporadic, with either no causative mutation identified or no familial history of ALS. Recently, the discovery of C9orf72 hexanucleotide repeat expansions have been identified as one of the most common causes of familial ALS, with some patients presenting with dual phenotypes of ALS and frontotemporal dementia, leading to new hypotheses about the nature of neurodegenerative diseases. Despite the continued discovery of new ALS causative genes, little is known about the pathogenesis of the disease. While almost all variants include the presence of intracellular protein inclusions, the site of the protein plaques and involved proteins varies between genetic and phenotypic variants of this disease. Due to the lack of clear pathogenic mechanisms, several hypotheses have been developed to explain the process of neurodegeneration. Autophagy, the process of self-eating, leading to destruction of damaged or excess proteins and organelles, has been implicated as being altered in ALS. Multiple variants have demonstrated altered mitochondrial morphology and cellular energetic dynamics, which could explain previous observations that implicate the process of apoptosis in cellular death. Many of the involved proteins in ALS have functional roles for intracellular, nucleocytoplasmic, and axonal transport of various proteins or RNA. These three competing hypotheses are currently the most prominent hypotheses in the pathogenesis of ALS, and have largely been considered as separate and competing in past research. Is there a chance that the true pathogenesis leading to neuronal destruction via apoptosis involve all three hypotheses? Altered protein and RNA transport dynamics could lead to changes in cellular stress responses or overload autophagy pathways, leading to exacerbated cellular stress responses, leading to alterations in mitochondrial morphology and eventually cell death via apoptosis.

Carotenoid pigments in W. dermatitidis, the first pathogenic, dematiaceous fungus in which carotenoid pigments nave been reported, are located primarily (81%) in lipid organelles which floated on the surface of the supernatant fraction of lysed cells. Pigment in this fraction could be extracted with ethyl ether without prior treatment with acetone indicating the pigment is unbound in the lipid organelle. Eight percent remains after exhaustive ether extraction and is recovered after the sample is treated with acetone indicating this fraction is non-covalently bound to proteins in the membranes associated with the lipid organelle. The remaining pigment (about 12%) represents contamination of the supernatant with the lipid organelles.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22887号 / 医博第4681号 / 新制||医||1048(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 武藤 学, 教授 小川 誠司, 教授 藤田 恭之 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM