Thesis (Ph. D.)--Cornell University, May, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Microbiology and Molecular Biology, 2005. / Includes bibliographical references.

Thesis (M.S.)--University of Florida, 2005. / Typescript. Title from title page of source document. Document formatted into pages; contains 57 pages. Includes Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 79-82).

Orientador: Antonio Carlos Alessi / Banca: Rosangela Zacarias Machado / Banca: José Luiz Guerra / Banca: João Santana da Silva / Banca: Valéria Marçal Felix de Lima / Resumo: A compreensão do comportamento da microglia frente a uma injúria viral contribui para o entendimento da dimensão da rede de comunicação celular, durante um processo degenerativo ou inflamatório no SNC. Pesquisas que utilizam modelos experimentais com o vírus da estomatite vesicular (VEV) têm colaborado com informações importantes sobre o comportamento e distribuição do agente no encéfalo, e também sobre o papel da resposta imune na resolução ou no agravamento das lesões nervosas. Neste estudo, foi comparada a evolução do quadro neurológico induzido pelo VEV, por meio de técnicas de imunoistoquímca, em cérebros de camundongos. Foi possível observar que o VEV causa severa degeneração e necrose do neurópilo, com lesão direta em neurônios, pois estes mostraram-se claramente positivos para o vírus, por meio da reação de imunoistoquímica no cérebro. A reação astrocitária foi intensa nos animais infectados, porém a densidade destas células reduziu com o aumento da gravidade das lesões. As células residentes (neurônios, astrócitos e microglia) e as células inflamatórias expressaram MIP-1a e, em menor proporção, MIP-1b. A microgliose reativa foi significativa nos animais com sintomatologia clínica. A diversidade morfológica da microglia foi grande, variando desde uma forma fusiforme a uma ramificada e a forma arredondada fagocítica das áreas necróticas. Foi possível observar que existe uma profunda interação entre as células residentes do SNC - neurônios, microglia, astrócitos, endotélio, frente ao estímulo viral. Baseado nos relatos da literatura é importante salientar que os astrócitos mantêm um controle ativo sobre a microglia tanto em repouso quanto ativada, via citocinas/quimiocinas. A densidade aumentada dessas células coincidiu com a redução do número de astrócitos, devido à necrose do neurópilo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The comprehension of the microglial cell behavior in a viral injury colaborate for the understanding of the dimension of the cellular communication net, during a degenerative or inflammatory process in central nervous system (CNS). Experimental models with the vesicular stomatitis virus (VSV), has contributed with important information about the behavior and distribution of virus in the CNS. Such studies evaluated the role of the immune response in the resolution or in the damage of the nervous lesions. In this study, the evolution of the neurological signals and lesions induced by VSV infection in mice was studied, using imunohistochemical techniques. It was observed that VSV causes severe degeneration and necrosis of the neuropil and direct lesions to the neurons. The neurons were the most intensively stained cells for the virus in the brain. The reactive astrocitosis was intense in the infected animals, but the density of these cells reduced with the increase of the gravity of the lesions. The resident and inflammatory cells expressed MIP-1a and in smaller proportion MIP-1b, in different cellular types (neurons, astrocytes and microglia). The reactive microgliosis was significant in animals with clinical symptomatology and there was a great morphologic microglial diversity, varying from a fusyforme form and ramified form and the fagocitic round form of the around necrotics areas. It was possible to observe that a close interaction exists among the resident cells of SNC (neurons, microglia, astrocytes, endothelial cells) in face of the viral infection. Based on the reports of the literature it is important to point out that the astrocytes maintains an active control on the microglia (in resting or activated cells), through citokines/chemokines. The increased density of microglia coincided with the reduction of the astrocytes number, due to the necrosis of the neuropil... (Complete abstract, access undermentioned eletronic address) / Doutor

This study examined the rehabilitation potential of AM fungi with organic and inorganic fertilisers under pot and field trial conditions as well as their interaction with rhizospheric organisms and specific functional groups. In addition, the study highlighted the effects of land-use management on AM fungal populations in soil and the mycorrhizal status of some selected plants from one of the study sites. The study focussed on two sites that differ in operational activities and these included a mined area that was to be rehabilitated and a commercial farming site. A pot trial was conducted using an overburdened soil resulting from kaolin clay mining. Pots were seeded with Cynodon dactylon and treated with either Organic Tea or NPK (3:1:5) fertiliser, with or without AM fungal inoculum. The compatibility of these fertilisers with AM fungi was assessed by plant growth and percentage root colonisation. Maximum shoot height and plant biomass were observed at the 28th week with NPK (3:1:5) fertiliser supporting mycorrhizal colonisation by 80%. The result indicated the potential of AM fungi to be used in rehabilitation with minimal phosphate fertiliser. Similarly, a field trial was set-up using 17 x 17 m[superscript 2] plots in the mining site that were treated with the same organic and inorganic fertilisers as well as with AM fungal inoculum in different combinations. The interaction between AM fungi and soil microbial population was determined using culture dependent and culture independent techniques. The culture dependent technique involved the use of soil dilution and plating on general purpose and selective media. The result showed that there was no change in the total culturable bacterial number in the untreated and AM fungal treated plots, while a change in species composition was observed in the functional groups. Different functional groups identified included nitrogen fixing bacteria, pseudomonads, actinomycetes, phosphate solubilisers and the fungal counterparts. Gram-positive bacteria were observed as the predominant phenotypic type, while nitrogen fixers and actinomycetes were the predominant functional groups. Species identified from each functional group were Pseudomonas fulva, Bacillus megaterium, Streptomyces and actinomycetales bacteria. Meanwhile, fungi such as Ampelomyces, Fusarium, Penicillium, Aspergillus, Cephalosporium and Exserohilium were identified morphologically and molecularly. Furthermore, the mining site had a significantly higher bacterial number than the farming site thereby indicating the effects of land-use management on culturable bacterial numbers. The culture independent technique was carried out by cloning of the bacterial 16S rDNA and sequencing. Identified clones were Bradyrhizobium, Propionibacterium and Sporichthya. A cladogram constructed with the nucleotides sequences of identified functional species, clones and closely related nucleotide sequences from the Genbank indicated that nucleotide sequences differed in terms of the method used. The activity and establishment of the introduced AM fungal population was determined by spore enumeration, infectivity assay, percentage root colonisation and assessment of glomalin concentrations. The results indicated that the two land use types affected AM fungal populations. However, the establishment of AM fungi in the farming site was more successful than in the mining site as indicated by the higher infectivity pontential. Selected host plants, which were collected around the mine area, were observed to be mainly colonised by AM fungi and these were identified as Pentzia incana, Elytropappus rhinocerotis, Euphorbia meloformis, Selago corymbosa, Albuca canadensis and Helichrysum rosum. These plant species were able to thrive under harsh environmental conditions, thereby indicating their potential use as rehabilitation host plants. Generally, the findings of this study has provided an insight into the interaction between arbuscular mycorrhizal fungi and other soil microorganisms in two fields with differing land use management practices.

As critical regulators of vesicular trafficking, Rab proteins comprise the largest GTPase family, with thirty-eight functionally distinct members and another twenty isoforms in the human genome. Activated Rab GTPases interact with effector proteins involved in vesicle formation, transport, tethering, docking and fusion. The specificity of Rab interactions with effectors and regulatory factors plays a central role with respect to the fidelity of membrane trafficking. Rab recognition determinants and the mechanisms underlying interactions with structurally diverse regulatory factors and effectors are complex and poorly understood. Using Rab5 mediated endocytic transport as a model system, the work described in this thesis provides insight into the structural basis underlying the interaction of effectors and regulatory factors with Rab GTPases. In addition, structural and biochemical approaches have been used to define how specific Rab5 interacting proteins function in the endocytic and recycling pathways. These results establish novel structural and functional concepts that can be tested using family wide analyses of Rab GTPase recognition determinants and regulatory roles in the cell.

abstract: This study evaluates five different hypotheses potentially accounting for the prehistoric movement of vesicular basalt during the Hohokam occupation of the Salt-Gila Basin (ca. A.D. 700-1450): 1) direct procurement; 2) direct exchange; 3) down-the-line exchange; 4) market exchange; and 5) elite-controlled exchange. The plausibility of each hypothesis is assessed by examining the relative frequency of different vesicular basalt source types at sites as related to the geographic distance from their source; intra-site variance in vesicular basalt source type diversity; inter-site variance in vesicular basalt source type diversity; and temporal specificity and continuity in source preference. The study sample is comprised of 484 vesicular basalt artifacts recovered from nine Hohokam sites: Casa Grande, Gila Crossing, the Hospital Site, La Plaza, Las Colinas, Los Hornos, Lower Santan, Pueblo Grande, and Upper Santan. Geographic provenance data for artifacts are generated by comparing their chemical composition to a geochemical reference database composed of more than 700 vesicular basalt raw material samples from 17 different source areas in the Salt-Gila Basin. Geochemical data for both artifact and raw material samples were collected using a portable X-ray fluorescence spectrometer and a newly developed sampling procedure that provides an efficient, reliable, and nondestructive means of analysis. The results of the hypothesis testing found that direct procurement is a possible material provisioning practice for perhaps only a small number of households in the Salt-Gila Basin; specifically those located less than 10 km from a vesicular basalt outcrop. Direct exchange is also an unlikely explanation, though it cannot be rejected outright. The other exchange hypotheses, down-the-line, market, and elite-controlled exchange, as defined in this study, are all rejected as possible explanations. From these results, a new model of Hohokam vesicular basalt provisioning practices is developed for future testing. This model posits that vesicular basalt groundstone tools were produced by specialists in a handful of locations during both the Preclassic and Classic periods, and that finished tools were acquired through workshop procurement or local distributers. The implications of these findings for understanding the organization of Hohokam domestic and political economies are also discussed. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2014

HIV infection represents a major health and socioeconomic challenge worldwide. Despite significant advances in therapy, a cure for HIV continues to be elusive. The design of novel curative strategies will require targeting and elimination of cells that constitute the latent HIV-1 reservoir. However, such an approach is impeded by the inability to distinguish latently HIV-infected cells from uninfected cells. The type-I interferon (IFN-I) response is an integral antiviral defense mechanism, but is impaired at multiple levels during productive HIV infection. Interestingly, similar global impairments in IFN-I signaling have been observed in various human cancers. This led to the development of IFN-sensitive oncolytic viruses, including the recombinant Vesicular Stomatitis Virus (VSV 51) and Maraba virus (MG1), as virotherapy designed to treat various cancers. Based on this, it was hypothesized that IFN-I signaling is impaired in latently HIV-infected cells (as observed in productively infected cells) and that VSV 51 and MG1 may be able to exploit such intracellular defects to target and eliminate latently HIV-infected cells, while sparing healthy cells. First, using cell line models of HIV-1 latency, intracellular defects in IFN-I responses, including impaired IFN / production and expression of IFNAR1, MHC-I, ISG15, and PKR, were demonstrated to represent an important feature of latently HIV-infected cells. Consistent with this, the latently HIV-infected cell lines were observed to have a greater sensitivity to VSV 51 and MG1 infection, and MG1-mediated killing, than the HIV-uninfected parental cells. Next, the ability of oncolytic viruses to kill latently HIV-infected human primary cells was demonstrated using an in vitro resting CD4+ T cell model of latency. Interestingly, while both VSV 51 and MG1 infection resulted in a significant reduction in inducible p24 expression, a dose-dependent decrease in integrated HIV-1 DNA was only observed following MG1 infection. In keeping with this, MG1 infection of memory CD4+ T cells from HIV-1 infected individuals on HAART also resulted in a significant decrease in inducible HIV-1 gag RNA expression. By targeting an intracellular pathway that is impaired in latently HIV-infected cells, the findings presented in this dissertation highlight a novel, proof-of-concept approach to eliminate the latent HIV-1 reservoir. Given that VSV 51 and MG1 are currently being studied in cancer clinical trials, there is significant potential to translate this work to in vivo studies.

Avec une prévalence de 1% dans la population générale, le trouble bipolaire (TB) est une maladie psychiatrique commune, chronique et sévère. Les études familiales réalisées pour cette affection ont montré une contribution génétique forte dans la prédisposition au TB, plus particulièrement pour les formes à début précoce de la maladie (TBDP). Malgré tout, les mécanismes moléculaires à l'origine de la maladie restent mal connus. Ainsi, suivant une étude de liaison génétique, nous avons pu identifier des variations rares dans un gène codant la protéine activatrice de l'exocytose dépendante du calcium (CADPS for Calcium- dependant activator protein for secretion) chez des patients avec un TBDP. CADPS est une protéine essentielle pour la régulation de l'exocytose et du chargement vésiculaire des monoamines dans les cellules neuronales et neuroendocrines. Nous avons étudié l'impact de ces mutations sur la fonction de ce gène, et montré que plusieurs d'entre elles altéraient son expression ainsi que ses fonctions. D'autre part, nous nous sommes intéressés au modèle murin privé d'un allèle de Caps (Caps1+/-) et montré que celles-ci décrivaient des comportements hyperactifs ainsi qu'une réponse au stress variable comparée aux souris sauvages.L'ensemble de nos résultats suggèrent pour la première fois que ce gène pourrait jouer un rôle dans les formes à début précoce de trouble bipolaire et ouvrent de nouvelles voies de recherche pour comprendre les mécanismes moléculaires qui sont altérés chez les sujets atteints. / Summary not transmitted