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Mycobacterium avium ssp. paratuberculosis (Map), agent étiologique de la paratuberculose, a évolué en deuxtypes dénommés, S pour« Sheep » et C pour « Cattle ». L’intestin grêle est le site primaire de l’infection à Map mais les mécanismes moléculaires impliqués dans l’implantation du bacille restent largement méconnus. L’objectif de mon projet de thèse visait à identifier et caractériser les adhésines exprimées par Map par des approches génétiques et biochimiques. J’ai ainsi purifié la HBHA et la LBP par chromatographie d’affinité puis les ai identifiés en spectrométrie de masse. L’originalité de ce travail repose sur le polymorphisme de ces adhésines observé entre les souches de type C et S. Cette variabilité a été mise en évidence sur le domaine d’interaction avec les sucres sulfatés de la cellule hôte influençant l’affinité des adhésines pour l’héparine. Ce travail de thèse a permis de caractériser pour la première fois ces deux adhésines produites par Map. Le polymorphisme de la HBHA et de la LBP, discriminant les types C et S, ouvre de nombreuses perspectives sur l’évolution de l’espèce M. avium et le rôle de ces adhésines sur le tropisme intestinal, la préférence d’hôte de Map ou encore leur potentiel diagnostic. / Mycobacterium avium subsp. paratuberculosis (Map), the etiological agent of paratuberculosis, has evolved into two types called, S for "Sheep" and C for "Cattle." The small intestine is the primary site of Map infection but the molecular mechanisms involved in the establishment of bacilli are still unknown. The aim of my thesis was to identify and characterize the adhesins expressed by Map by genetic and biochemical approaches. I purified HBHA and LBP by affinity chromatography then identified them by mass spectrometry. The originality of this work is based on the polymorphism of these adhesins observed between strains of type C and S. This variability has been demonstrated in the binding domain involved in interaction with sulfated sugars of host cell influences adhesins affinity for heparin. This thesis has characterized for the first time these two adhesins produced by Map. Specific polymorphism highlighted related to the evolution of the species avium, opens large number questions on their role on the pathogenesis of Map including the cellular tropism, host preference or interest of these antigens to improve diagnostic.

Pest control of cultivated plant species has been usually performed by insecticides, which is undesirable because of economical and environmental concerns, since successive applications affect natural enemies and increase the possibility of development of resistant population toward insecticides. These problems can be minimized with alternative control methods as the use of resistant varieties, use of substances that induce resistance and biological control. Those studies involving the interaction of plant, pest and natural enemies are of fundamental importance. Thus, this study aimed: a) to study the effect of volatile organic compounds in tritrophic interactions between pepper Capsicum spp., the aphid Aphis gossypii and its parasitoid Aphidius colemani; b) to study the role of cis-jasmone in the tritrophic interaction between the pepper, the aphid A. gossypii and the parasitoid A. colemani and its role in activating the defense mechanism of the plant. Pepper varieties were evaluated for resistance to the aphid A. gossypii and their volatiles were collected before and after infestation. Volatiles compounds were tentatively identified by gas chromatography/mass spectrometry. Olfactometry bioassays were performed with volatile regarding the behavior of A. gossypii and A. colemani. The main conclusions obtained in this work were: a) there is genetic variability among genotypes of Capsicumin relation to the release of volatile compounds and in the susceptibility toward A. gossypii; b) genotype Cambuci can be used in breeding programs aiming Capsicum cultivars more resistant to A. gossypii; c) there were significant differences between the effects of volatiles from the two cultivars on behavior of A. gossypii and A. colemani; d) the volatiles emitted by Cambuci cultivar after infestation produced repellent effect on A. gossypii and were attractive to A. colemani; e) the cis-jasmone applied to pepper plants provided emission of volatiles that had repellent action on the A. gossypii and attractive one to A. colemani; f) the genetic variability between genotypes, after infestation indicates that volatile organic compounds present as variables can be used for selection and development of bell pepper cultivars resistant to the aphid A. gossypii. / O controle de pragas das espécies vegetais cultivadas tem sido normalmente realizado por meio de inseticidas, o que é indesejável tanto por motivos econômicos quanto ambientais, já que as aplicações sucessivas afetam os inimigos naturais e aumentam a possibilidade de desenvolvimento de populações da praga resistentes aos inseticidas. Esses problemas podem ser minimizados com métodos alternativos de controle como o emprego de variedades resistentes, o uso de substâncias indutoras e o controle biológico. Para isso, estudos envolvendo a interação planta, praga e inimigo natural são de fundamental importância. Dessa forma, este trabalho teve como objetivos: a) Estudar a ação dos compostos orgânicos voláteis na interação tritrófica entre o pimentão Capsicum spp., o pulgão Aphis gossypiie seu parasitóide Aphidiuscolemani; b) Estudar a ação da cis-jasmona na interação tritrófica entre o pimentão, o pulgão A. gossypii e o parasitóide A. colemani e seu papel na ativação do mecanismo de defesa do vegetal. Variedades de pimentão foram avaliadas em relação à resistência ao pulgão A. gossypii e os seus compostos voláteis foram coletados antes e após a infestação. Os compostos voláteis foram tentativamente identificados por cromatografia gasosa/espectrometria de massas. Bioensaios de olfatometria foram realizados com os compostos voláteis em relação ao comportamento de A. gossypii e A. colemani. As principais conclusões obtidas neste trabalho foram: a) Existe variabilidade genética entre os genótipos de Capsicum em relação à emissão de compostos voláteis e em relação à susceptibilidade ao A. gossypii; b) O genótipo Cambuci poderá ser utilizado em programas de melhoramento genético visando cultivares de Capsicum mais resistentes ao A. gossypii; c) Houve diferenças significativas entre os efeitos dos compostos voláteis das duas cultivares sobre os comportamentos de A. gossypii e de A. colemani; d) Os compostos voláteis emitidos pela cultivar Cambuci após a infestação proporcionaram efeito repelente a A. gossypii e atrativo a A. colemani; f) A cis-jasmona aplicada sobre plantas de pimentão induziu a emissão e/ou produção de compostos voláteis que teve ação de repelência a A. gossypii e ação atraente para A. colemani; i) A variabilidade genética entre os genótipos, após a infestação, indica que os compostos orgânicos voláteis apresentam-se como variáveis que podem ser utilizadas para seleção e desenvolvimento de cultivares de pimentão resistente ao pulgão A. gossypii.

Made available in DSpace on 2014-12-17T15:36:59Z (GMT). No. of bitstreams: 1 RicardoAL_DISSERT.pdf: 2035586 bytes, checksum: ca26983e504667d744bf6cb052c449e0 (MD5) Previous issue date: 2010-05-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Recently, capuchin monkeys (Cebus spp.) inhabitants of dry environments and with restriction of fleshy fruits, have been the subject of several studies regarding the use of instruments. During behaviour of using stones to crack open nuts there is evidence of selection of more effective hammers, as well as selection of anvils related to reducing the risk of predation. The aim of this study was to determine whether two groups of capuchin monkeys (C.flavius and and C.libidinosus) inhabitants of the Caatinga of Rio Grande do Norte make choice of hammers and anvils. The record of weight and location of stones indicated active choices of with what (choice of hammers) and where (selection of anvils) to crack open encapsulated seeds. The choice of hammers to break nuts depended on the type and degree of ripeness seed. Thus, smaller seeds were smashed with lighter hammers and larger seeds with heavier hammers. Still, C. flavius was the only species that presented a refinement in the choice of hammers that depended on the ripeness of seeds. For both species of capuchin monkeys studied, the nut-crack sites were not spread in accordance with the spatial distribution of seed-producing species, suggesting that the capuchin monkeys promote active choice of anvils. Thus, in environments with more escape routes through the trees, the nut-crack sites were found further apart than in regions that had less chance of escape through the trees. Also, there was a difference in the spacing of the anvils to depend on the type of seed: sites used to crack larger and more caloric seeds were found farther apart than the sites used to crack smaller and less caloric seeds, suggesting a pattern of avoiding direct competition. We conclude that the capuchin monkeys maximize energy savings and reduced risk of predation and the costs of food competition during the behaviour of using stones to crack open nuts / Recentemente, macacos prego (Cebus spp.) habitantes de ambientes secos e com restri??o de frutos carnosos, v?m sendo alvo de diversos estudos acerca do uso de instrumentos. Em atividades de quebra de sementes, h? ind?cios de escolhas eficientes de martelos, bem como de sele??o de bigornas para redu??o dos riscos de preda??o. O objetivo deste trabalho foi verificar se dois grupos de macacos prego (C. flavius e C. libidinosus) habitantes da caatinga do Rio Grande do Norte realizam escolhas de martelos e bigornas. O registro do peso e da localiza??o das pedras indicou escolhas ativas de com o que (escolha de martelos) e onde (sele??o de bigornas) quebrar sementes encapsuladas. O padr?o de escolha dos martelos para quebrar sementes dependeu da esp?cie e do estado de matura??o. Assim, sementes menores foram quebradas com martelos mais leves e sementes maiores com martelos mais pesados. Ainda, C. flavius foi a ?nica esp?cie que apresentou um refinamento na escolha de martelos que dependia do estado de matura??o de sementes. Para ambas as esp?cies de macacos prego estudadas, os s?tios de quebra n?o estavam dispostos de acordo com a distribui??o espacial das esp?cies produtoras de sementes, sugerindo que os macacos prego promovem escolha ativas de bigornas. Assim, em ambientes que havia maior chance de fuga atrav?s das ?rvores, os s?tios de quebra foram encontrados mais afastados entre si do que em regi?es que havia menor chance de fuga pelas ?rvores. Tamb?m, foi verificada diferen?a no espa?amento das bigornas a depender do tipo de semente: s?tios de quebra de sementes maiores e mais cal?ricas foram encontrados mais distantes entre si do que os s?tios de quebra de sementes menores e menos cal?ricas, sugerindo um padr?o de evitac?o de competi??o direta. Conclu?mos que os macacos prego maximizam os ganhos energ?ticos e reduziram os riscos de preda??o bem como os custos de competi??o por alimento durante o comportamento de uso de pedras para quebra de sementes

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Brazil is the main world producer of sugarcane (Saccharum ssp.), being the activity of the Brazilian sugarcane industry in continuous expansion, which can be seen due to increasing both the production capacity as agricultural areas intended for the cultivation. However, the increase of the production costs and the expansion of cultivation to less productive areas have increasingly demanded strategies to safeguard the sector's profitability. In this sense, studies of environmental factors that limit the yield of sugarcane crops are fundamental and can cite the biotic stresses caused by pathogenic microorganisms and the weeds. Plants respond differently to various types of stress, and, in general, are firstly affected in their physiological and photosynthetic properties. Therefore, the analysis of ecophysiological parameters - being this a tool to detect small deviations from normality of the photosynthetic performance - can provide useful information about the behavior of plants under stressful conditions caused by the disease and weed competition. Thus, this study aimed to evaluate the behavior of four different sugarcane varieties submitted to the stresses caused by the bacterium Leifsonia xyli subsp. xyli (Lxx) - causal agent of Ratoon stunting disease (RSD) - and competition with the weed plant Brachiaria decumbens Stapf., correlating the production data with the ecophysiological responses resulting from the stress condition. To this finality, stem segments with just one bud were planted in plastic trays and kept in a greenhouse, being the seedlings subsequently transplanted to the field, where were measured both yield parameters (biometric and technological), the fluorescence of chlorophyll a and the gas exchange of plants subject, or not, to mentioned stressors. The experimental design used was the randomized block design with four replications, in a split-plot scheme, being the plots composed by varieties Co 997, RB867515, RB92579 and RB951541; and the subplots by the induction or not of stress factor. Regarding Lxx inoculation, RB92579 and RB951541 varieties were less sensitive to the RSD effects, since both ecophysiological and yield parameters were just a little bit affected by disease, while RB867515 and Co 997 varieties underwent changes in many parameters, highlighting the decline of photosynthetic rate and the reduction of height and diameter of the stalks. Regarding weed competition with B. decumbens, the four varieties tested were affected in all parameters, resulting in significant losses of yield, being that the RB92579 variety showed higher competitive ability than the others. Thus, the use of ecophysiological analysis tool is feasible to aid the work of selection of tolerant sugarcane genotypes to typical adverse situations of his cultivation. / O Brasil é o principal produtor mundial de cana-de-açúcar (Saccharum ssp.), entando a atividade do setor sucroenergético brasileiro em contínua expansão, o que pode ser constatado devido ao aumento crescente tanto da capacidade produtiva como das áreas agrícolas destinadas à cultura. No entanto, o aumento dos custos de produção e a expansão do cultivo para áreas menos produtivas têm exigido cada vez mais estratégias capazes de salvaguardar a rentabilidade do setor. Nesse sentido, os estudos dos fatores ambientais que limitam o rendimento dos canavias são fundamentais, podendo-se citar os estresses bióticos causados pelos microrganismos fitopatogênicos e pelas plantas infestantes. As plantas respondem de formas diferentes aos diversos tipos de estresse, sendo que, em geral, são primeiramente afetadas em suas propriedades fisiológicas e fotossintéticas. Isto posto, a análise dos parâmetros ecofisiológicos – sendo uma ferramenta capaz de detectar pequenos desvios da normalidade do desempenho fotossintético – pode fornecer informações úteis acerca do comportamento das plantas sob as condições estressantes causadas por doenças e pela matocompetição. Assim, o presente estudo teve por objetivo avaliar o comportamento de quatro diferentes variedades de cana-de-açúcar submetidas aos estresses causados pela bactéria Leifsonia xyli subsp. xyli (Lxx) – agente causal da doença Raquitismo da soqueira (RSD) – e pela competição com a planta infestante Brachiaria decumbens Stapf., correlacionando os dados de produção com as respostas ecofisiológicas decorrentes da condição de estresse. Para tal, segmentos de colmo com apenas uma gema foram plantados em bandejas plásticas e mantidos em casa de vegetação, sendo as mudas posteriormente transplantadas para o campo, onde foram mensurados os parâmetros de produção (biométricos e tecnológicos), a fluorescência da clorofila a e as trocas gasosas de plantas sujeitas ou não aos fatores de estresse mencionados. Foi utilizado o delineamento experimental em blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas, sendo as parcelas compostas pelas variedades Co 997, RB867515, RB92579 e RB951541; e as subparcelas pela imposição ou não do fator de estresse. Em relação à inoculação de Lxx, as variedades RB92579 e RB951541 foram menos sensíveis aos efeitos do RSD, uma vez que, tanto parâmetros ecofisiológicos como de produção foram pouco influenciados pela doença, ao passo que as variedades RB867515 e Co 997 sofreram alterações em diversos parâmetros, com destaque para o declínio da taxa fotossintética e redução da estatura e diâmetro dos colmos. Em relação à matocompetição com B. decumbens, as quatro variedades testadas foram afetadas em todos os parâmetros, acarretando em perdas expressivas de produtividade, sendo a variedade RB92579 a que demonstrou maior habilidade competitiva. Assim, uso da ferramenta de análise ecofisiológica é viável no auxílio aos trabalhos de seleção de genótipos de cana-de-açúcar tolerantes às situações adversas própria do seu cultivo.

Made available in DSpace on 2014-07-29T15:13:40Z (GMT). No. of bitstreams: 1 TESE Bruno Medrado.pdf: 1863730 bytes, checksum: 142fb795d040f53ab90b6225b9c56530 (MD5) Previous issue date: 2010-04-10 / The main economic activity of the state of Tocantins, in Brazilian Amazon is cattle farms, with extensive breeding. Looking for contribution to cattle sanity, this study was devoted to the prevalence of antibodies against Leptospira in livestock of those farms, as production animals (cattle and equids), dogs and animal workers, from a rural governmental settlement in Aragominas, in the northwestern part of Tocantins. The statistically proofed sample was composed by 242 cows, 78 equids, 59 dogs and 41 animals workers, distributed in 38 small properties. All sampling was performed after informed consent, written in the case of human beings. For the diagnosis of leptospirosis, microscopic seroagglutination was performed in the Laboratório de Diagnóstico de Leptospirose do Setor de Medicina Veterinária Preventiva da Escola de Medicina Veterinária da UFG, Goiânia-GO. The seroprevalence for Leptospira spp in cattle was 76,5% [70,7% 81,7%], with serovar predominance of Hardjo (26,2%), followed by Wolffi (23,4%) Hebdomadis (14,1%), Castellonis (11,7%), Grippotyphosa (9,1%) e Pyrogenes (4,8%). In equids the seroprevalence was 79,3% [68,9% 87,4%], with agglutinins more intense to wild life serovars Castellonis (24,4%), Grippotyphosa (13,7%), Patoc (13,1%), Butembo (8,9%), Pomona (7,1%), Hardjo (6,6%), Pyrogenes (6,6%) e Wolffi (6,6%). Dogs presented seroprevalence of 30,5% [19,2 43,9], prevailing Canicola (26,3%), Hardjo (13,3%), Bratislava (10,0%) and Pyrogenes (10,0%). Human leptospirosis seroprevalence in animal workers was 31,7% [18,1%-48,1%], cwith detections of serovars Hardjo (26,3%), Grippotyphosa (15,8%), Pyrogenes (10,5%), Wolffi (10,5%), Autumnalis (10,5%) e Bratislava (10,5%). Looking for association with environmental and breeding conditions, the seroprevalence was associated in cattle to Bos indicus cattle (OR=7,51; [0,99-56,97]), in equids to the use of antihelminths (OR=7,64[0,95 61,50]) and for dogs with use for shepherd cattle (OR=4,44[1,35 14,58]). These data point to endemicity of Leptospira infection in the area and are highly suggestive of extensive environmental contamination with wildlife and production animal serovars. These results also emphasize the importance of the control of livestock leptospirosis, lowering environmental contamination and allowing better animal sanitation, with measures that could be implemented in new adequate settlements. / A exploração pecuária bovina constitui-se em uma atividade fundamental para o Estado do Tocantins, que tem sua economia pautada no agronegócio. Visando contribuir para a sanidade bovina na região, objetivou-se neste estudo determinar a prevalência de anticorpos anti-Leptospira spp. em animais de interesse econômico (bovinos e equinos), em cães e em humanos que tinham contato direto com animais, oriundos de assentamento rural do município de Aragominas, Tocantins, Brasil. A amostragem estatisticamente representativa foi constituída por 242 bovinos, 78 equídeos, 59 cães e 41 humanos, distribuídos em 38 propriedades. As colheitas de sangue dos animais e a aplicação de questionários foram realizadas após o aceite dos proprietários e, no caso dos humanos, após a leitura e assinatura do termo de consentimento livre e esclarecido. Para diagnóstico da leptospirose foi empregada a técnica de soroaglutinação microscópica (SAM) realizada no Laboratório de Diagnóstico de Leptospirose do Setor de Medicina Veterinária Preventiva da Escola de Medicina Veterinária da UFG, em Goiânia-GO. A prevalência de infecção por Leptospira spp. em bovinos foi de 76,5% [70,7% 81,7%], com predominância de anticorpos aos sorovares Hardjo (26,2%), seguido do Wolffi (23,4%), Hebdomadis (14,1%), Castellonis (11,7%), Grippotyphosa (9,1%) e Pyrogenes (4,8%); em equídeos foi de 79,3% [68,9% 87,4%], com maior detecção de aglutininas para os sorovares Castellonis (24,4%), Grippotyphosa (13,7%), Patoc (13,1%), Butembo (8,9%), Pomona (7,1%), Hardjo (6,6%), Pyrogenes (6,6%) e Wolffi (6,6%). Já em cães, foi detectada soroprevalência de 30,5% [19,2 43,9], com maiores respostas aos sorovares Canicola (26,3%), seguido Hardjo (13,3%), Bratislava (10,0%) e Pyrogenes (10,0%) e em humanos constataram-se 31,7% [18,1%-48,1%] de reagentes, com detecção de anticorpos para os sorovares Hardjo (26,3%), Grippotyphosa (15,8%), Pyrogenes (10,5%), Wolffi (10,5%), Autumnalis (10,5%) e Bratislava (10,5%). Dentre os fatores avaliados, a prevalência mostrou-se associada na espécie bovina à raça zebu (OR=7,51; [0,99-56,97]), nos equídeos ao uso de vermífugo (OR=7,64[0,95 61,50]) e para cães a lida com gado (OR=4,44[1,35 14,58]). Os resultados encontrados apontam para uma situação de endemicidade e são sugestivos de alta contaminação ambiental por sorovares que possuem como hospedeiro natural animais de produção e silvestres; evidenciando a necessidade de controle da infecção animal, com a finalidade de diminuir a contaminação ambiental e a consequente infecção em seres humanos.

The mechanical properties achieved with high performance wrought aluminium alloys are superior to cast aluminum alloys. To obtain an intricate shaped component, wrought alloys are commonly subjected to forging followed by subsequent machining operation in the automobile industry. As machining of such high strength wrought aluminium alloys adds to cost, productivity gets affected. Shortening the process by near net shaped casting would tremendously enhance productivity. However, casting of such alloys frequently encounter hot tear defect. Therefore, circumventing hot tear to successfully die cast near net shaped wrought alloy components is industrially relevant. A recent advanced casting process, namely ‘Semisolid Die casting’, is proposed as a likely solution. Hot tearing originates due to lack of liquid flow in the inter-dendritic region. To reduce hot tear susceptibility, fine and non-dendritic grain structure is targeted, amenable for processing by semisolid route. For semisolid processing an adequate freezing range for processing is required. Accordingly A6061 wrought alloy whose composition is tuned with higher silicon and magnesium content within the grade limits, is chosen for the study. With the objective of obtaining fine and non-dendritic microstructured billets, electromagnetic stirring (EMS) and cooling slope (CS) methods are employed. On conducting a parametric study with EMS, a finest possible primary α-Al grain size of about 70 μm is obtained at low stirring time at stirring current levels of 175 A and 350 A, with the addition of grain refiner. CS, on the other hand, rendered a grain of 60 μm at a slope length of 300 mm at a slope angle of 45° with grain refiner addition. Of the two methods, CS billets are chosen for subsequent induction heating. A 3-step induction heating cycle has been devised to attain a temperature of 641°C in the billet on the basis of factors including coherency point, viscosity of the slurry and solid fraction sensitivity with temperature. The billet microstructure is found to be homogenous throughout after quenching in water. The characterization of phase along primary α-Al grain boundary and its composition analysis is done by SEM and EPMA respectively, after billet casting as well as induction heating. In addition, the bulk hardness is determined in BHN. The induction heated billets are semisolid die cast to produce an engine connecting rod used in automobiles. The microstructure is characterized at various locations, and is found to consist of smooth α-Al grains in a background matrix of fine grains formed due to secondary solidification. The component hardness is found to be 66 BHN comparable with A6061 alloy under T4 heat treated condition. X-ray radiography does not confirm presence of surface hot tear, which is the normal defect associated with casting of wrought aluminium alloys. No defects are observed along the constant cross-sectional area of the connecting rod, suggesting that the processing could be suitable for semisolid extrusion.

No description available.

>Magister Scientiae - MSc / The study focusses on the transport sector, where company participation level is measured at approximately 20% of levy paying enterprises, and this level is mostly based on relatively high levels of participation from large and medium sized companies. The study explores the relationship between SETAs (sector education training authorities) and the companies within the sectors they are mandated to serve by researching the TETA maritime sub sector. The research focus is on small companies and the focus is specifically on the low rate of participation of smaller entities in the skills development landscape. The consequences of the lack of participation are investigated and the study concludes that the SETAs ability to effectively research its sector skills, as well as the SETAs ability to provide effective skills planning in support of the national agenda, are both negatively affected by current levels of poor participation. The research was conducted on small fishing companies registered with the Transport Education and Training Authority (TETA), in order to determine the reasons for low participation in the government mandatory grant scheme. The research is survey based across participating small companies and non-participating small companies.