Made available in DSpace on 2017-05-12T14:47:09Z (GMT). No. of bitstreams: 1 TESE_ FRANCIELI .pdf: 3210488 bytes, checksum: 139233665a2fb9191412af6ecba0f292 (MD5) Previous issue date: 2015-02-06 / The composting process has been used as the main way to stabilize agro-industrial waste from the broiler production chain. These wastes are generated in the run-fattening stage and during the slaughtering and processing of meat, originally inadequate to composting process due to its high levels of nitrogen. The objective of this research was to evaluate different lignocellulosic materials available regionally as a carbon source to be added to the composting process. The lignocellulosic materials were carding cotton waste, pruning of urban trees, sawdust, crushed sugarcane bagasse and crushed napier grass, which mixed with other wastes (reproductive poultry bedding, hatchery waste, flotation sludge, sausage skins and coal from boilers), constituted the treatments. Five windrows were set up and monitored, with C:N ratio of around 30. The windrows were turned twice a week in the first month and once a week in the following months until stabilization, confirmed by the decline of the windrow temperature until it reaches values of room temperature. At every turning, moisture was adjusted to 60%. The time of composting was evaluated, as well as mass reductions and volume (parameters related to optimization of the composting area); losses of N, P and K; concentration of N, P and K and the ratio of humic to fulvic acid - HA / FA that to characterize the agronomic value of the final compost, in addition to monitoring of microbiological parameters such as basal respiration and activity enzymatic β-glucosidase, cellulase, acid and alkaline phosphatase. With the aid of techniques of Multivariate Analysis (Cluster Analysis and Principal Component), it was concluded that the treatment which used the carding cotton waste as a carbon source allowed optimizing the use of composting area and provided the production of a organic compost with greater agronomic value. Regarding the microbiological parameters, these were most intense in the thermophilic phase, being the cellulase activity most accentuated. / O processo de compostagem é utilizado como principal forma de estabilizar resíduos agroindustriais provenientes da cadeia produtiva do frango de corte. Trata-se dos resíduos gerados no período que antecede a fase de engorda e durante o abate e industrialização da carne, originalmente inadequados ao processo de compostagem por apresentarem altos teores de nitrogênio. Objetivou-se avaliar diferentes materiais lignocelulósicos disponíveis regionalmente como fonte de carbono a ser adicionado na compostagem destes resíduos. Os materiais lignocelulósicos avaliados foram: resíduos da desfibrilação do algodão, podas de árvores urbanas, serragem, bagaço de cana moído e capim napier triturado, que em mistura com os demais resíduos (cama de matrizeiro, resíduos de incubatório, lodo de flotador, tripa celulósica e carvão), constituíram os tratamentos. Foram montadas e monitoradas cinco leiras, com relação C:N em torno de 30. As leiras foram revolvidas duas vezes por semana no primeiro mês e uma vez por semana nos meses seguintes até a estabilização, confirmada pelo declínio da temperatura da leira até atingir os valores da temperatura ambiente. A cada revolvimento, a umidade foi corrigida para 60%. Os parâmetros avaliados foram o tempo de compostagem e as reduções de massa e volume (parâmetros relacionados à otimização do pátio de compostagem); perdas de N, P e K, concentração de N, P e K e relação ácidos húmicos:ácidos/fúlvicos AH/AF que permitiram caracterizar o valor agronômico do composto final. Monitorou-se os parâmetros microbiológicos, como a respiração basal e a atividade enzimática de β-glucosidase, celulase, fosfatase ácida e alcalina. Com auxílio de técnicas da Análise Multivariada (Análise de Agrupamento e de Componentes Principais), concluiu-se que o tratamento em que se utilizou o resíduo da desfibrilação de algodão como fonte de carbono permite otimizar a utilização do pátio de compostagem e proporciona a produção de um composto orgânico com maior valor agronômico. Com relação aos parâmetros microbiológicos, estes foram mais intensos na fase termofílica, sendo a atividade de celulase a mais pronunciada

People can differ in their attitudes toward apalic syndrome patients. Health care staff, however, would always be professional. They deal with a human being, a person who can sense. This fact should form a framework for both health care professionals and patients´ families. Especially nurses should be very sensitive, calm and good-tempered so that they could take adequate care of apalic patients. The empiric part of the thesis was elaborated through qualitative and quantitative research survey. The qualitative method, an interview, was used in the first phase of the survey. The data were collected through semi-structured interviews with the family members of apalic patients and the nurses of health care facilities. Although the interviews for the family members and the nurses differed in some parts, they contained common identification questions and specific information. The interviews were anonymous and consisted of 16 questions for the family members and 10 questions for the nurses.

INTRODUÇÃO: O carcinoma basocelular (CBC) é o tipo de câncer cutâneo mais comum no ser humano. O aparecimento de CBC na maioria das vezes se dá de forma esporádica em indivíduos que se expõem cronicamente ao sol. Eventualmente pode estar associado a síndromes, como: Bazex-Dupré- Christol, Rombo e Gorlin-Goltz. Diferente do que ocorre nas síndromes, os casos de CBCs múltiplos familiares não sindrômicos(CBCMFNS) são poucos estudados, tendo na literatura somente cinco relatos de famílias com a doença. O fenótipo é de múltiplos CBCs superficiais sem presença de outras anormalidades. Devido os CBCs esporádicos e os CBCs presentes na Síndrome de Gorlin-Goltz apresentarem mutações no gene PTCH1, possivelmente os CBCs múltiplos também estejam associados a alterações neste gene. Este gene esta localizado na região 9q22.3 possuindo 23 éxons, tem um papel importante na formação embrionária e de supressão tumoral. OBJETIVO: Análise genética dos éxons 9,11, 16, 17 e 23 do PTCH1 de oito componentes da mesma família, pertencentes a três diferentes gerações, sendo três portadores de CBCs múltiplos, e dentre estes dois suspeitos de CBCMFNS. MÉTODOS: Extração de DNA dos leucócitos do sangue periférico; PCR; clonagem dos produtos de amplificação (pGEM T Easy Vector) e seqüenciamento (Big Dye Terminator Kit). As mutações e polimorfismos encontrados foram comparados com a literatura e banco de dados de mutação do gene PTCH1 (www.cybergene.se/PATCH). RESULTADOS: Duas novas mutações foram encontradas nos pacientes suspeitos de CBCMFNS: uma frameshift nt4130(del C) e uma missense nt4261(A->G). Nos familiares foram encontradas cinco novas mutações: Em um primeiro indivíduo uma missense nt1420(G->T); em um segundo a mesma missense nt1420(G->T) e mais uma missense nt2873(C->T); em um terceiro duas frameshift nt1443 (ins T) e nt1468 (ins T), em dois outros indivíduos, irmãos, uma outra mutação missense nt4130(C->T). Foram encontradas ainda dezoito mutações, não descritas anteriormente, nos íntrons 10,15,16 e 17, algumas se repetindo em todos os indivíduos analisados. CONCLUSÃO: Pela primeira vez estão sendo descritas mutações em éxons e íntrons do gene PTCH1 em indivíduos portadores de CBCMFNS e em alguns de seus familiares. / INTRODUCTION: Basal cell carcinomas (BCC) are the most usual skin cancer that affects human beings. Sporadic BCCs are prevalent, often arising in people chronically exposed to UV radiation from the sun. Eventually BCCs may be associated to different syndroms like Bazex-Dupré-Christol, Rambo and Gorlin. Contrarily to syndromic BCCs, the cases of multiple familiar nonsydromic BCCs(MFNSBCC) have only few studies found in the literature. Only five families have been described to date with the disease. Since sporadic and Gorlin BCCs are associated to many mutations in the PTCH1 gene, we hypothesized that the multiple BCCs phenotype is also associated with mutations in this same gene. The PTCH1 tumor suppressor gene is located in the 9q22.3 chromosomal region, contains 23 exons, and has an important role in embryogenesis. OBJETIVE: To perform genetic analysis of PTCH1 exons 9, 11, 16, 17 e 23. METHODS: Eight individuals belonging to different generations from the same family were studied. Three of them bore multiple BCCs, and two of those were suspect to have MFNSBCC. DNA was extracted from blood leukocytes, submitted to PCR, and the PCR products were cloned (pGEM T Easy Vector, Promega) and sequenced (Big Dye Terminator Kit; ABI Prism 3100 sequencer; Applied Biosystems). The polymorphisms and mutations found were analyzed and compared to literature and PTCH1database (www.cybergene.se/PTCH/). RESULTS: In the patients suspect of MFNSBCC were found two new mutation: one frameshift nt4130(del C) and one missense nt4261(A->G). In the relatives were found five new mutation: Three missense nt1420(G->T); nt2873(C->T); nt4130(C->T); and two frameshift nt1443 (ins T) and nt1468 (ins T). In the introns 10,15,16 and 17 were found eighteen new mutations that were not previously reported. CONCLUSION: For the first time mutation in exons and introns of PTCH1 gene have been described in patients bore MFNSBCC and some of their relatives.

A proteína S100<font face=\"symbol\">b no cérebro é produzida e secretada pela célula da glia astrócito, e exerce de acordo com sua quantidade extracelular, ação trófica ou tóxica sobre os neurônios. Investigamos a distribuição da proteína S100<font face=\"symbol\">b, no animal em condição basal, realizando o mapeamento em diferentes áreas do encéfalo, com a técnica imuno-histoquímica, explorando a hipótese do aparecimento de S100<font face=\"symbol\">b em áreas encefálicas preferenciais. A distribuição da proteína foi analisada pela técnica do imuno-histoquímica, com utilização de anticorpo anti-S100 (<font face=\"symbol\">b subunidade). O mapeamento da proteína S100<font face=\"symbol\">b ao longo do eixo AP, permitiu observar marcação de elementos gliais distribuídos pelo telencéfalo, diencéfalo, e tronco encefálico, onde a proteína apresentou-se preferencialmente distribuída, na comparação dos animais. Nossos resultados sugerem que a proteína pode estar relacionada ao fato dessa distribuição ser conservada como padrão dentro da espécie. / S100<font face=\"symbol\">b protein is expressed primarily by astroglia in the brain, and practice functional implication of S100<font face=\"symbol\">b secretion by astrocytes into the extracellular space is scant but there is substantial evidence that secreted glial S100<font face=\"symbol\">b exerts trophic or toxic effects depending on its concentration. We provide here a detailed description of the distribution of the calcium-binding protein S100<font face=\"symbol\">b in and glial elements in the encefalo of rats. The distribution of S100-like immunoreactivity was analyzed by antisera: monoclonal, the b subunit (S100b) of this protein. All sera showed glial positive elements, which were more abundant in the brainstem than in the prosencephalon. S100-immunoreactive was detected in glial elements, in different regions of the telencephalon, diencephalon and mesencephalon. This distribution appears very similar to that, as well as to sparse observations on different vertebrates. Therefore, our results suggest that the distribution pattern of this protein in glial elements is highly conserved between the species.

Made available in DSpace on 2014-07-29T14:52:08Z (GMT). No. of bitstreams: 1 Tese cicero agronomia.pdf: 980115 bytes, checksum: fc39630e9c5fb7bef0bb3944a6ce5081 (MD5) Previous issue date: 2009-04-16 / Different soil organic matter pools under management systems and natural Cerrado vegetation were studied. These pools were estimated using their carbon and nitrogen contents. Total soil organic carbon and total nitrogen (COT and NT), carbon and nitrogen of particulate organic matter (COP and NP), mineral-associated organic carbon and nitrogen (COM and NM), particulate organic carbon associated with different aggregates size classes (COPA), microbial biomass carbon and nitrogen contents (CBM and NBM) and their relations, and basal respiration as a measure of microbial activity, were determined in this study. Eight treatments were used: seven soil management systems and an undisturbed area of Savanna type vegetation, Cerrado, as a reference. They were: heavy disk harrow and legume species cultivation during twelve years (GP); disk plow and legume species cultivation during twelve years (AD); minimum tillage with chisel plow starting five years after installing the experiment (ESC); no-tillage with biennial crop rotation: grass and legume species as cover crop (PD1); no-tillage with crop rotation and annual cover crops (PD2), no-tillage with annual crop rotation of grass and legume species (PD3), permanent pasture (PAST) and natural savanna vegetation, cerrado (CER). The experiment was established in a randomized blocks design with three replicates to study soil tillage and crop rotation dynamics, with temporal and spatial alternation. Soil samples were taken at five depths: 0-5, 5-10, 10-20, 20-30 and 30-40 cm. Soil samples were collected in February, 2008, at soybean flowering stage. The soil management systems cause changes on soil organic carbon contents mainly on particulate organic matter (> 53 &#956;m) and microbial biomass fractions as compared to the Cerrado vegetation. The annual use of plow discs to soil tillage causes increase of associated minerals-organic matter levels. In soil and climatic conditions of Cerrado, the use of no-till system preceded by soil chemical and structural correction has promote a more uniform distribution of particulate organic matter in the profile. The microbial biomass is responsive to changes caused by different soil management systems in the Cerrado / Foram estudados diferentes compartimentos da matéria orgânica do solo sob sistemas de manejo e vegetação natural de Cerrado. Esses compartimentos foram estimados por meio de seus conteúdos de carbono e nitrogênio. Determinaram-se: carbono orgânico e nitrogênio total do solo (COT e NT, respectivamente); carbono e nitrogênio da matéria orgânica particulada (> 53 &#956;m) (COP e NP, respectivamente); carbono e nitrogênio orgânicos associados a minerais (COM e NM, respectivamente); carbono orgânico particulado associado a classes de agregados (COPA); carbono e nitrogênio da biomassa microbiana (CBM e NBM, respectivamente) e suas relações; e respiração basal como medida da atividade microbiana. Utilizaram-se oito tratamentos: sete com sistemas de manejo do solo e um com vegetação natural de Cerrado, como referência. Os sistemas estudados foram: uso de grade pesada e cultivado com leguminosas há doze anos (GP); uso de arado de discos e cultivado com leguminosas há doze anos (AD); preparo mínimo com escarificador a partir do quinto ano de experimento (ESC); plantio direto com alternância bienal de gramíneas e leguminosas (PD1); plantio direto com rotação bienal e safrinha (PD2); plantio direto com alternância anual de gramíneas e leguminosas (PD3); pastagem permanente (PAST); e cerrado nativo (CER). O experimento foi projetado para estudar a dinâmica de sistemas de preparo do solo e a rotação de culturas, com alternância no tempo e no espaço. O delineamento experimental utilizado foi o de blocos ao acaso com três repetições. As amostras de solo foram coletadas em cinco profundidades: 0-5, 5-10, 10-20, 20-30 e 30-40 cm. A amostragem de solo foi realizada em fevereiro de 2008, por ocasião da floração da soja. Alterações nos teores de carbono orgânico pelo uso do solo no Cerrado ocorreram, principalmente, na fração particulada da matéria orgânica (> 53 &#956;m) e na fração microbiana do solo (CBM), quando comparadas ao cerrado nativo. Com o uso freqüente de arado de discos no preparo do solo, ocorre aumento dos teores de matéria orgânica associada aos minerais. Nas condições edafoclimáticas do Cerrado, o uso do sistema de plantio direto, precedido de correção química e estrutural do solo, promove uma distribuição mais uniforme da matéria orgânica particulada no perfil. A biomassa microbiana é sensível às mudanças causadas pelos diferentes sistemas de manejo do solo no Cerrado

Made available in DSpace on 2017-07-10T19:23:56Z (GMT). No. of bitstreams: 1 TESE_ FRANCIELI .pdf: 3210488 bytes, checksum: 139233665a2fb9191412af6ecba0f292 (MD5) Previous issue date: 2015-02-06 / The composting process has been used as the main way to stabilize agro-industrial waste from the broiler production chain. These wastes are generated in the run-fattening stage and during the slaughtering and processing of meat, originally inadequate to composting process due to its high levels of nitrogen. The objective of this research was to evaluate different lignocellulosic materials available regionally as a carbon source to be added to the composting process. The lignocellulosic materials were carding cotton waste, pruning of urban trees, sawdust, crushed sugarcane bagasse and crushed napier grass, which mixed with other wastes (reproductive poultry bedding, hatchery waste, flotation sludge, sausage skins and coal from boilers), constituted the treatments. Five windrows were set up and monitored, with C:N ratio of around 30. The windrows were turned twice a week in the first month and once a week in the following months until stabilization, confirmed by the decline of the windrow temperature until it reaches values of room temperature. At every turning, moisture was adjusted to 60%. The time of composting was evaluated, as well as mass reductions and volume (parameters related to optimization of the composting area); losses of N, P and K; concentration of N, P and K and the ratio of humic to fulvic acid - HA / FA that to characterize the agronomic value of the final compost, in addition to monitoring of microbiological parameters such as basal respiration and activity enzymatic &#946;-glucosidase, cellulase, acid and alkaline phosphatase. With the aid of techniques of Multivariate Analysis (Cluster Analysis and Principal Component), it was concluded that the treatment which used the carding cotton waste as a carbon source allowed optimizing the use of composting area and provided the production of a organic compost with greater agronomic value. Regarding the microbiological parameters, these were most intense in the thermophilic phase, being the cellulase activity most accentuated. / O processo de compostagem é utilizado como principal forma de estabilizar resíduos agroindustriais provenientes da cadeia produtiva do frango de corte. Trata-se dos resíduos gerados no período que antecede a fase de engorda e durante o abate e industrialização da carne, originalmente inadequados ao processo de compostagem por apresentarem altos teores de nitrogênio. Objetivou-se avaliar diferentes materiais lignocelulósicos disponíveis regionalmente como fonte de carbono a ser adicionado na compostagem destes resíduos. Os materiais lignocelulósicos avaliados foram: resíduos da desfibrilação do algodão, podas de árvores urbanas, serragem, bagaço de cana moído e capim napier triturado, que em mistura com os demais resíduos (cama de matrizeiro, resíduos de incubatório, lodo de flotador, tripa celulósica e carvão), constituíram os tratamentos. Foram montadas e monitoradas cinco leiras, com relação C:N em torno de 30. As leiras foram revolvidas duas vezes por semana no primeiro mês e uma vez por semana nos meses seguintes até a estabilização, confirmada pelo declínio da temperatura da leira até atingir os valores da temperatura ambiente. A cada revolvimento, a umidade foi corrigida para 60%. Os parâmetros avaliados foram o tempo de compostagem e as reduções de massa e volume (parâmetros relacionados à otimização do pátio de compostagem); perdas de N, P e K, concentração de N, P e K e relação ácidos húmicos:ácidos/fúlvicos AH/AF que permitiram caracterizar o valor agronômico do composto final. Monitorou-se os parâmetros microbiológicos, como a respiração basal e a atividade enzimática de &#946;-glucosidase, celulase, fosfatase ácida e alcalina. Com auxílio de técnicas da Análise Multivariada (Análise de Agrupamento e de Componentes Principais), concluiu-se que o tratamento em que se utilizou o resíduo da desfibrilação de algodão como fonte de carbono permite otimizar a utilização do pátio de compostagem e proporciona a produção de um composto orgânico com maior valor agronômico. Com relação aos parâmetros microbiológicos, estes foram mais intensos na fase termofílica, sendo a atividade de celulase a mais pronunciada

The striatum represents the main input nucleus of the basal ganglia, a system of subcortical nuclei critically involved into motor control and motivational processes and altered in several conditions such as Parkinson’s diseases or drug addiction. The projection neurons of the striatum are GABAergic (γ-aminobutyric acid) medium-sized spiny neurons (MSNs), and account for the large majority of striatal neurons, while interneurons represent about 10% of striatal cells. The MSNs are subdivided into two subpopulations that form two main efferent pathways: the striatonigral and striatopallidal neurons. The striatonigral MSNs project to the entopeduncular nucleus (EP) and substancia nigra pars reticulata (SNr) (direct pathway) and co-express dopamine D1 receptors (D1R) and substance P neuropeptide (SP). On the other hand, striatopallidal MSNs project to the lateral globus pallidus (LGP) (indirect pathway) and co-express dopamine D2 receptor (D2R), adenosine A2A receptor (A2AR) and enkephalin (Enk). The D1R striatonigral and D2R striatopallidal MSNs are equal in number and shape and are mosaically distributed through all the striatum. The dorsal striatum is mainly involved in motor control and learning while the ventral striatum is crucial for motivational processes. In view of the still debating respective functions of projection D2R-striatopallidal and D1R-striatonigral neurons and striatal interneurons, both in motor control and learning of skills and habits but also in more cognitive processes such as motivation, we were interested in the development of models allowing the removal of selective striatum neuronal populations in adult animal brain. Because of the mosaical organisation of the striatum, a targeting of specific neuronal type, with techniques such as chemical lesions or surgery, is still impossible. Taking advantage of new transgenic approaches, the goal of the present work was to generate and/or to initiate the characterization of genetic models in which a selective subtype of striatal neuron can be ablated in an inducible way. We used a transgenic approach in which mice express a monkey diphtheria toxin (DT) receptor (DTR) in D2R-striatopallidal or D1R-striatonigral neurons. Local stereotactic injections of DT can then induce selective neuronal ablation in functionally different striatal areas.<p>We first investigated functions of D2R-striatopallidal neurons in motor control and drug reinforcement by their selective ablation in the entire striatum or restricted to the ventral striatum. This DTR strategy produced selective D2R striatopallidal MSN ablation with integrity of the other striatal neurons as well as the striatal dopaminergic function. D2R MSN ablation in the entire striatum induced permanent hyperlocomotion while ventral striatum-restricted ablation increased amphetamine place preference.<p>We next compared respective roles of D2R-striatopallidal and D1R-striatonigral neurons in motor control and skill learning in functionally different striatum subregions.<p>Finally, to target nitrergic interneurons of the striatum, we developed a bacterial artificial chromosome genetic strain in which the cre-recombinase expression is under the control of the neuronal nitric oxide gene promoter.<p><p>Altogether, those results show that DTR expression and DT local injections is an efficient and flexible strategy to ablate selective striatum neuronal types with spatial resolution. We provide the first direct experimental evidences that D2R striatopallidal neurons inhibit both locomotor and drug-reinforcement processes and that D2R and D1R MSNs in different striatum subregions have distinct functions in motor control and motor skill learning. Those results strongly support a cell-type and topographic functional organization of the striatum and underscore the need for characterization of the specific cellular and molecular modifications that are induced in D2R and D1R MSNs during drug-reinforcement or procedural learning.<p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Le système cholinergique est impliqué dans les phénomènes d’attention, de mémoire et d’apprentissage et les récepteurs cholinergiques régulent de multiples fonctions du système nerveux central. Néanmoins, leur rôle au niveau de la modulation des propriétés du cortex visuel reste à être établi. L’un des objectifs de cette thèse était d’étudier le rôle des récepteurs muscariniques impliqués dans le fonctionnement normal du cortex visuel. Nous avons pu déterminer que les récepteurs muscariniques sont impliqués dans l’établissement de nombreuses propriétés visuelles telles la taille des champs récepteurs, la sensibilité au contraste, la sélectivité à la fréquence spatiale et la finesse de la connectivité corticale. L’autre objectif était d’identifier les récepteurs cholinergiques impliqués dans la potentiation des capacités visuelles. Nous avons amélioré le traitement cognitif de l’information visuelle par stimulation électrique du télencéphale basal (noyau où sont localisés les corps cellulaires cholinergiques) et par la stimulation cholinergique par le donépézil, un inhibiteur de l’acétylcholinestérase. La combinaison répétée d’une stimulation visuelle et cholinergique (qu’elle soit électrique ou pharmacologique) améliore similairement l’activité corticale visuelle. Toutefois, les récepteurs impliqués ne sont pas les mêmes. Suite à la stimulation pharmacologique, ce sont principalement les récepteurs muscariniques qui influencent l’acuité visuelle de manière tardive et cette modulation est plus précoce lors de la stimulation électrique. Ces résultats démontrent que le couplage répétitif d’une stimulation cholinergique et d’une stimulation visuelle est en mesure d’améliorer l’activité corticale visuelle. Le fait de connaître les récepteurs cholinergiques impliqués permettra dans un futur proche de les cibler directement pour améliorer la fonction corticale. / The cholinergic system is involved in attention, learning and memory and cholinergic receptors regulate multiple functions of the central nervous system. Nevertheless, their role in modulating the properties of the visual cortex remains to be established. One of the objectives of this thesis was to study the role of muscarinic receptors involved in the normal function of the visual cortex. We have been able to determine that the muscarinic receptors are involved in the establishment of many visual properties such as the size of the receptor fields, contrast sensitivity, spatial frequency selectivity and accuracy of the cortical connectivity. The other objective was to identify the cholinergic receptors involved in the potentiation of visual abilities. We improved the cognitive processing of visual information by electrical stimulation of the basal forebrain (the nucleus where the cholinergic cell bodies are located) and by cholinergic stimulation using donepezil, an acetylcholinesterase inhibitor. The repeated combination of visual and cholinergic stimulations (whether electrical or pharmacological) similarly enhances visual cortical activity. However, the receptors involved are not the same. Following the pharmacological stimulation, it is mainly the muscarinic receptors that influence visual acuity with a delay in the receptors expression and this modulation is earlier for the electrical stimulation. These results demonstrate that repetitive coupling of cholinergic stimulation and visual stimulation can enhance visual cortical activity. Knowing the cholinergic receptors involved will allow in a near future to target them directly to improve cortical function.

Indiana University-Purdue University Indianapolis (IUPUI) / Physical and biological phenomena that involve oscillations on multiple time scales attract attention of mathematicians because resulting equations include a small parameter that allows for decomposing a three- or higher-dimensional dynamical system into fast/slow subsystems of lower dimensionality and analyzing them independently using geometric singular perturbation theory and other techniques. However, in most life sciences applications observed dynamics is extremely complex, no small parameter exists and this approach fails. Nevertheless, it is still desirable to gain insight into behavior of these mathematical models using the only viable alternative – ad hoc computational analysis. Current dissertation is devoted to this latter approach. Neural networks in the region of the brain called basal ganglia (BG) are capable of producing rich activity patterns. For example, burst firing, i.e. a train of action potentials followed by a period of quiescence in neurons of the subthalamic nucleus (STN) in BG was shown to be related to involuntary shaking of limbs in Parkinson’s disease called tremor. The origin of tremor remains unknown; however, a few hypotheses of tremor-generation were proposed recently. The first project of this dissertation examines the BG-thalamo-cortical loop hypothesis for tremor generation by building physiologically-relevant mathematical model of tremor-related circuits with negative delayed feedback. The dynamics of the model is explored under variation of connection strength and delay parameters in the feedback loop using computational methods and data analysis techniques. The model is shown to qualitatively reproduce the transition from irregular physiological activity to pathological synchronous dynamics with varying parameters that are affected in Parkinson’s disease. Thus, the proposed model provides an explanation for the basal ganglia-thalamo-cortical loop mechanism of tremor generation. Besides tremor-related bursting activity BG structures in Parkinson’s disease also show increased synchronized activity in the beta-band (10-30Hz) that ultimately causes other parkinsonian symptoms like slowness of movement, rigidity etc. Suppression of excessively synchronous beta-band oscillatory activity is believed to suppress hypokinetic motor symptoms in Parkinson’s disease. Recently, a lot of interest has been devoted to desynchronizing delayed feedback deep brain stimulation (DBS). This type of synchrony control was shown to destabilize synchronized state in networks of simple model oscillators as well as in networks of coupled model neurons. However, the dynamics of the neural activity in Parkinson’s disease exhibits complex intermittent synchronous patterns, far from the idealized synchronized dynamics used to study the delayed feedback stimulation. The second project of this dissertation explores the action of delayed feedback stimulation on partially synchronous oscillatory dynamics, similar to what one observes experimentally in parkinsonian patients. We employ a computational model of the basal ganglia networks which reproduces the fine temporal structure of the synchronous dynamics observed experimentally. Modeling results suggest that delayed feedback DBS in Parkinson’s disease may boost rather than suppresses synchronization and is therefore unlikely to be clinically successful. Single neuron dynamics may also have important physiological meaning. For instance, bistability – coexistence of two stable solutions observed experimentally in many neurons is thought to be involved in some short-term memory tasks. Bistability that occurs at the depolarization block, i.e. a silent depolarized state a neuron enters with excessive excitatory input was proposed to play a role in improving robustness of oscillations in pacemaker-type neurons. The third project of this dissertation studies what parameters control bistability at the depolarization block in the three-dimensional conductance-based neuronal model by comparing the reduced dopaminergic neuron model to the Hodgkin-Huxley model of the squid giant axon. Bifurcation analysis and parameter variations revealed that bistability is mainly characterized by the inactivation of the Na+ current, while the activation characteristics of the Na+ and the delayed rectifier K+ currents do not account for the difference in bistability in the two models.

Thesis (PhDAgric (Plant Pathology))--Stellenbosch University, 2010. / ENGLISH ABSTRACT: In the Western Cape onion industry in South Africa, Fusarium oxysporum Schlechtend.:Fr. f.sp. cepae (H.N. Hans.) W.C. Snyder & H.N. Hans. (Focep) has been identified as the leading cause of harvest and storage losses. This pathogen is of world-wide importance and causes Fusarium basal rot of onions (Allium cepa), affecting all onion growth stages. No information is available on the evolution, genetic diversity, molecular detection and inoculum sources of the South African Focep population. Similar to what is the case for South Africa, limited information is available on Focep in other regions of the world. World-wide, four vegetative compatibility groups (VCGs) and two single-member VCGs (SMVs) have been identified among two Japanese and 19 Colorado (USA) isolates. This polyphyletic origin of Focep suggested by VCG analyses was confirmed through molecular analyses of isolates from a few countries. Only the mating type (MAT)1-1 idiomorph has been reported for Focep isolates from Welsh onion (Allium fistulosum). The development of sustainable management strategies of Focep is dependent on knowledge of (i) the genetic diversity and evolution of Focep, (ii) whether high throughput molecular methods can be developed for identifying the most virulent and widespread Focep genotypes and (iii) the role of seedlings and seeds as primary inoculum sources, and the Focep genotypes associated with these growth stages. Therefore, the three main aims of the current study were to investigate the aforementioned three aspects. In the first aim of the study, the genetic diversity and evolution of Focep was investigated using a collection of 79 F. oxysporum isolates from South Africa (27 Focep and 33 non-pathogenic isolates) and Colorado (19 Focep isolates). VCG analyses revealed the presence of six VCGs, four among the Colorado Focep isolates (VCGs 0421, 0422, 0423 and 0424) and two among the South African bulb-associated isolates (VCGs 0425 and 0426). VCG 0421 and VCG 0425 were the two main VCGs in Colorado and South Africa, respectively. Four SMVs and one heterokaryon selfincompatible (HSI) isolate were also identified. The polyphyletic nature of Focep in South Africa and Colorado was shown through a combined translation elongation factor 1α (EF-1α) and mitochondrial small-subunit (mtSSU) phylogeny. The phylogeny divided the Focep isolates into two main clades, of which one contained the two main VCGs (0421 and 0425), SMVs and non-pathogenic isolates. The second, ancestral clade contained the HSI isolate, VCGs 0422, 0423 and 0424, and non-pathogenic isolates. Unlike the clade containing the two main VCGs, which were highly virulent toward onion bulbs, the ancestral clade contained isolates that were mostly moderately virulent. The incongruence of the EF-1α and mtSSU datasets with an intergenic spacer (IGS) region data set, and the presence of both MAT idiomorphs within the same isolate for some isolates, suggested possible exchange of genetic material between isolates. The second aim of the study was to develop molecular methods for identifying the two main Focep VCGs (0425 and 0421), using DNA fingerprinting methods and sequence-characterized amplified region (SCAR) markers. These techniques were first developed using the F. oxysporum isolates from the first aim, and were then used to investigate the prevalence of VCG 0425 among 88 uncharacterized F. oxysporum isolates from onion bulbs in South Africa. Two random amplified polymorphic DNA primers provided two diagnostic amplicons for VCG 0425, but attempts to develop SCAR markers from these amplicons were unsuccessful. In contrast, an interretrotransposon amplified polymorphism (IRAP) fingerprinting method enabled the developed of a multiplex IR-SCAR polymerase chain reaction method that detected the VCG 0421, 0425 and SMV 4 isolates as a group. Fingerprinting and SCAR marker testing of the 88 uncharacterized F. oxysporum isolates from South Africa (65 Focep and 23 non-pathogenic) confirmed that VCG 0425 is the main VCG in South Africa associated with mature onion bulbs, since 63 of the Focep isolates had the molecular characteristics of VCG 0425. The third aim of the study was to determine whether seed and seedling transplants are inoculum sources of Focep, and whether the same genotype (VCG 0425) that dominated on mature bulbs could be detected from these sources. Focep isolates were obtained from seven of the 13 investigated onion seed lots, as well as from onion seedling transplants that were collected from all five onion nurseries in the Western Cape. Focep seedling infection more than doubled from the 6-week growth stage to the 14-week growth stage. Seed infections by Focep were low, but the seedborne nature of Focep was confirmed by showing that a green fluorescent protein labelled Focep transformant could be transmitted from infected soil to onion seed via the onion bulbs and seedstalks. It is thus clear that commercial seed and seedlings are inoculum sources of Focep. However, the Focep genotypes on seed and seedlings are different from those in mature bulbs and were not dominated by VCG 0425. Furthermore, most (≤ 60%) of the seed and seedling isolates were moderately virulent, as compared to the mostly highly virulent isolates from mature bulbs. / AFRIKAANSE OPSOMMING: In die Wes-Kaapse uiebedryf in Suid-Afrika is Fusarium oxysporum Schlechtend.:Fr. f.sp. cepae (H.N. Hans.) W.C. Snyder & H.N. Hans. (Focep) geïdentifiseer as die vernaamste oorsaak van oes- en opbergingsverliese. Hierdie patogeen is van wêreldwye belang; dit veroorsaak Fusarium-bolvrot van uie (Allium cepa) en affekteer alle plantgroeistadia. In Suid-Afrika is daar geen inligting beskikbaar oor die evolusie, genetiese diversiteit, molekulêre opsporing en inokulumbronne van die Focep-populasie nie. Soortgelyk aan wat die geval in Suid-Afrika is, is daar beperkte inligting beskikbaar oor Focep in ander wêrelddele. Wêreldwyd is daar vier vegetatiewe versoenbaarheidsgroepe (VVGe) en twee enkellid VVGe (ELVe) geïdentifiseer onder twee Japannese en 19 Colorado (VSA) isolate. Hierdie veelvuldige oorsprong van Focep wat deur VVG-analise voorgestel was, is deur die molekulêre analises van isolate uit ’n paar ander lande bevestig. Slegs die paringstipe (PT)1-1 idiomorf is vir Focep-isolate uit Walliese-tipe uie (ook bekend as ‘lenteuie’ in Suid Africa) (Allium fistulosum) berig. Die ontwikkeling van volhoubare bestuurstrategieë vir Focep steun op kennis van (i) die genetiese diversiteit en evolusie van Focep, (ii) of hoë-deurset molekulêre metodes ontwikkel kan word vir die identifisering van die mees virulente en wydverspreide Focep-genotipes en (iii) die rol van saailinge en saad as primêre inokulumbronne, en die Focep-genotipes wat met hierdie groeistadia geassosieer word. Daarom was die hoof doelstellings van hierdie studie om die bogenoemde drie aspekte te bestudeer. Om die eerste doel van die studie te bereik is die genetiese diversiteit en evolusie van Focep bestudeer deur gebruik te maak van ‘n versameling van 79 F. oxysporum-isolate uit Suid-Afrika (27 Focep en 33 nie-patogeniese isolate) en uit Colorado (19 Focep-isolate). VVG-analises het die teenwoordigheid van ses VVGe aangetoon – vier onder die Colorado Focep-isolate (VVGe 0421, 0422, 0423 en 0424) en twee onder die Suid-Afrikaanse bol-geassosieerde isolate (VVGe 0425 en 0426). VVG 0421 en VVG 0425 was die twee hoof VVGe in onderskeidelik Colorado en Suid-Afrika. Vier ELVe en een meerkernige self-onversoenbare (MSO) isolaat is ook geïdentifiseer. Die veelvuldige oorsprong van Focep in Suid-Afrika en Colorado is ook aangetoon deur ‘n gekombineerde translasie verlengings faktor 1α (VF-1α) en mitokondriale klein-subeenheid (mtKSE) filogenie. Dié filogenie het die Focepisolate in twee groepe verdeel, waarvan die een groep die twee hoof VVGe (0421 en 0425), ELVe en nie-patogeniese isolate bevat het. Die tweede, basal groepering het die MSO-isolaat, VVGe 0422, 0423 en 0424, en nie-patogeniese isolate bevat. In teenstelling met die eersgenoemde groepering wat hoogs virulente isolate van uiebolle bevat het, het die basale groepering isolate bevat wat meestal matig virulent was. Die inkongruensie van die VF-1α en mtKSE-datastelle met ‘n intergeen-gespasieerde (IGS) area datastel – asook die teenwoordigheid van beide PT-idiomorwe binne dieselfde isolaat by sommige isolate – het op ’n moontlike uitruiling van genetiese materiaal tussen isolate gedui. Die tweede doel van die studie was om molekulêre metodes te ontwikkel vir die identifisering van die twee hoof Focep VVGe (0425 en 0421) deur gebruik te maak van DNA-vingerafdrukke en nukleotied-gekarakteriseerde geamplifiseerde area (NKAA) merkers. Hierdie tegnieke is ontwikkel deur van die F. oxysporum-isolate van die eerste doelstelling gebruik te maak en is daarna gebruik om die frekwensie van VVG 0425 onder 88 ongekarakteriseerde F. oxysporum-isolate van uiebolle in Suid-Afrika te ondersoek. Twee gerandomiseerde geamplifiseerde polimorfiese DNS (RAPD) merkers het twee diagnostiese nukleotiedbasis-areas vir VVG 0425 gelewer, maar pogings om NKAA-merkers uit hierdie geamplifiseerde nukleotiedbasis-areas te onwikkel was onsuksesvol. In teenstelling hiermee het ‘n inter-retrotransposon geamplifiseerde polimorfisme (IRAP) vingerafdrukmetode die ontwikkeling van ‘n multipleks IR-NKAA polimerase kettingreaksiemetode moontlik gemaak wat die VVG 0421-, VVG 0425- en ELV 4-isolate as ’n groep aangedui het. Vingerafdruktoetsing en NKAA-merkertoetsing van die 88 ongekaraktariseerde F. oxysporum isolate van Suid-Afrika (65 Focep en 23 nie-patogenies) het bevestig dat VVG 0425 die hoof VVG in Suid-Afrika is wat met volwasse bolle geassosieer word, aangesien 63 van die Focep-isolate die molekulêre eienskappe van VVG 0425 gehad het. Die derde doel van die studie was om vas te stel of saad en saailinge inokulumbronne van Focep is, en of dieselfde genotipe (VVG 0425) wat op volwasse bolle dominant is, waargeneem kon word op hierdie bronne. Focep-isolate is verkry van sewe van die 13 uiesaadlotte asook van uiesaailinge wat in al vyf uiesaailingkwekerye in die Wes-Kaap versamel is. Focep-saailinginfeksie was meer as dubbel in die 14-week groeistadium as wat dit in die 6-week stadium was. Saadinfeksies deur Focep was laag, maar die saadgedraagde aard van Focep is bevestig deur aan te toon dat ’n Focep-transformant wat met ‘n groen fluoreserende proteïen geëtiketeer is, van geïnfekteerde grond na uiesaad oorgedra kon word via die uiebolle en -saadstele. Dit is dus duidelik dat kommersiële saad en saailinge as inokulumbronne van Focep dien. Die Focep-genotipes op saad en saailinge verskil egter van dié in volwasse bolle en is nie deur VVG 0425 gedomineer nie. Verder was die meeste (≤ 60%) saad- en saailingisolate matig virulent, in teenstelling met die meestal hoogs virulente isolate uit volwasse bolle.