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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Diversidade genética e estrutura de populações de Rhizoctonia solani AG-1 IA no Brasil /

Ciampi, Maísa Boff. January 2008 (has links)
Resumo: O basidiomiceto Rhizoctonia solani AG-1 IA é um dos principais patógenos da soja no Brasil, onde as perdas estimadas com a doença podem atingir 30 a 60%. 232 isolados de R. solani AG-1 IA foram coletados de campos comerciais de soja nas principais regiões produtoras do país e genotipados usando dez locos polimórficos de microssatélites. As baixas diversidades genotípicas, os desvios do equilíbrio de Hardy-Weinberg (EHW), o desequilíbrio gamético e o elevado grau de subdivisão populacional encontrados nessas populações são consistentes com predominância de reprodução assexuada e dispersão de propágulos vegetativos a curtas distâncias. Os níveis de subdivisão observados poderiam ser explicados pela migração histórica assimétrica entre as populações, indicando a população do Tocantins como a provável fundadora. As evidências de fluxo gênico restrito e modo reprodutivo misto enquadrariam o fungo na categoria de médio risco para potencial evolutivo de patógenos, sugerindo precaução quanto à aplicação de fungicidas ou melhoramento para genes de resistência. Também foi desenvolvido um método para detecção de SNPs em múltiplos locos por PCR, através da conversão de sondas de RFLP em seis marcadores co-dominantes de seqüenciamento, altamente informativos e polimórficos. Detectou-se de um a múltiplos alelos em cada isolado, para cada região analisada, indicando a condição heterocariótica do fungo. O maior número de polimorfismos SNPs foi detectado para o marcador R68L, com 18 mutações em 303 pares de bases. O conjunto de novos marcadores desenvolvido mostrou-se um sistema de genotipagem viável, possibilitando discriminação alélica precisa, com potencial de complementar os métodos existentes para estudo da biologia populacional de R. solani AG-1 IA e viabilizar estudos de caráter evolutivo. / Abstract: The Basidiomycete fungus Rhizoctonia solani AG-1 IA is a major pathogen of soybean in Brazil, where the average yield losses have reached 30 to 60%. 232 isolates of R. solani AG1 IA were collected from soybean fields in the most important soybean production areas in the country. These isolates were genotyped using ten microsatellite loci. Low genotypic diversity, departures from Hardy-Weinberg equilibrium (HWE), gametic disequilibrium and high degree of population subdivision found in these populations are consistent with predominantly asexual reproduction, short-distance dispersal of vegetative propagules, and limited long-distance dispersal. The observed levels of subdivision could be explained by asymmetric historical migration among the soybean-infecting populations, denoting TO06 as the founder population. Evidences of restricted gene flow and a mixed reproductive mode would fit the fungus into the medium-high risk category for pathogen evolutionary potential, suggesting the need for caution when applying fungicides or breeding for major-gene resistance. We also developed a method to detect SNPs in multiple loci by PCR, converting RFLP probes in six highly informative and polymorphic co-dominants sequencing markers. We have identified single and multiple alleles per isolate in each analyzed region, indicating the fungus heterokaryotic condition. The highest number of SNPs was detected at the R68L marker, with 18 mutations along 303 base pairs. The developed set of new markers proved to be a viable genotyping system, allowing precise allelic discrimination, with the potential to complement the methods already described to study the R. solani AG-1 IA population biology and making evolutionary studies feasible. / Orientador: Paulo Cezar Ceresini / Coorientador: Eliana Gertrudes Macedo Lemos / Banca: Lilian Amorim / Banca: Anete Pereira de Souza / Banca: Ester Wickert / Banca: João Ademir de Oliveira / Doutor
22

Ekologické rozdíly mezi bylinami a dřevinami a evoluce bylinnosti / Ecological differences between herbs and woody plants, and evolution of the herbaceous habit

Klimeš, Adam January 2020 (has links)
Ecological differences between herbs and woody plants, and evolution of the herbaceous habit Adam Klimeš, doctoral thesis Abstract Flowering plants (angiosperms), which make up most present-day vegetation, were originally woody. While flowering plants have repeatedly given rise to herbaceous lineages since their first appearance, we lack a clear explanation for these common evolutionary events. Freezing temperatures and drought periods have been proposed as factors which had caused huge success of the younger growth form but the evidence is very limited and not in favour of these hypotheses. In this thesis, we aimed to build the foundations of research on the evolution of herbs. We outlined new potential drivers of the evolution of herbs, suggested solutions to some methodological challenges and provided evidence about differences between herbs and woody plants relevant to the hypotheses on herb evolution. To this end, we used common garden experiments with young plants of both growth forms and global trait data from public databases which we evaluated using phylogenetic comparative techniques. Annuality of aboveground biomass and fast life-strategy of herbs are characteristics which differentiate them from woody plants and which in some conditions are expected to be behind their success. Apart from the...
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Tumeurs intra-thoraciques : mutations oncogéniques et problématiques cliniques : prédisposition génétique au cancer broncho-pulmonaire chez le patient non-fumeur : hétérogénéité inter- et intra- tumorale des cancers broncho-pulmonaires : étude génomique intégrative des tumeurs épithéliales du thymus / Clinical relevance of oncogenic mutations in thoracic oncology : genetic susceptibility to lung cancer in never-smokers : intra- and inter-tumoral heterogeneity of lung cancer : integrative genomic study of thymic epithelial tumors

Girard, Nicolas 05 September 2011 (has links)
Les protéines kinases de la voie de signalisation de l’Epidermal Growth Factor Receptor sont l’objet d’une dérégulation au cours des cancers broncho-pulmonaires. Les gènes encodant ces protéines sont porteurs de mutations oncogéniques mutuellement exclusives induisant la transformation tumorale des cellules de l’épithélium respiratoire. Ces mutations définissent autant de sous-groupes moléculaires spécifiques caractérisés sur le plan clinique, histologique, et biologique. Notre travail a consisté en l’étude de ces mutations dans trois situations cliniques spécifiques, les cancers broncho-pulmonaires du non-fumeur, les cancers bronchopulmonaires multiples, et les tumeurs thymiques. L’évaluation des polymorphismes génétiques chez les patients non-fumeurs atteints de cancer broncho-pulmonaire suggère le rôle de gènes spécifiques, différents de ceux impliqués chez le patient fumeur. L’étude génomique des cancers broncho-pulmonaires multiples montre la possibilité d’utiliser les mutations oncogéniques pour évaluer le degré de clonalité des lésions tumorales multiples, avec une corrélation significative avec leur analyse histo-pathologique détaillée. L’analyse génomique intégrative des tumeurs thymiques indique l’existence de sous-groupes moléculaires spécifiques, corrélés à la classification histologique, et caractérisés par des mutations oncogéniques prédictives de l’efficacité de certains traitements ciblés. Nos données illustrent les principes de la médecine personnalisée en oncologie thoracique, consistant en l’analyse des caractéristiques moléculaires de chaque tumeur individuelle, pour permettre une meilleure personnalisation de la prise en charge des patients / Oncogenic mutations may be identified in several genes of the Epidermal Growth Factor Receptor signaling pathway in non-small cell lung cancer. These mutations are transforming for epithelial cells of the respiratory tract through deregulation of the encoded proteins. These mutations are mutually exclusive and thus define molecular subsets of lung cancer with specific clinical, histological, and biological relevance. Here we integrated the use of mutation genotyping for the analysis of 3 specific clinical issues, including lung cancer occurring in never-smokers, multiple lung cancers, and thymic malignancies. Our results indicate that genetic polymophisms in never-smokers with lung cancer differ from those observed in smokers. Genomic profiling of multiple lung cancers suggests the feasibility of mutational profiling as a surrogate marker to evaluate the clonal relationships among multiple lung tumors, with a strong correlation with comprehensive histologic subtyping. Integrated genomic analysis of thymic malignancies identified specific molecular subsets, associated with histologic subtypes and oncogenic mutations predicting response to specific inhibitors. Taken together, our results illustrate the concept of personalized medicine in thoracic oncology, consisting of the individual analysis of molecular features of tumors to better tailor the therapeutic management of patients
24

Diversité génétique d'espèces structurantes en environnement marin : influence sur la réponse démographique des populations aux perturbations anthropiques / Genetic diversity of structuring species in the sea : influence on the demographic response to anthropic disturbances

Becheler, Ronan 28 November 2013 (has links)
L’influence de la diversité génétique sur la stabilité démographique des populations constitue un paradigme de l’écologie évolutive. Au sein des populations naturelles, l’étude de cette relation est complexifiée par l’influence réciproque de la stabilité sur la diversité, et leur degré d’interconnexion. Ces interrelations ont été explorées chez la plante marine Zostera marina et les coraux d’eau froide Lophelia pertusa et Madrepora oculata, des espèces partiellement clonales. Ce trait d’histoire de vie, influençant profondément la dynamique démographique et la trajectoire évolutive des espèces, a constitué le fil d’Ariane de ce travail. L’échantillonnage dans l’espace (échelle régionale) et le temps (un pas de trois ans) d’herbiers de Zostère a permis de mieux comprendre la dynamique clonale de ces plantes. L’architecture et la diversité clonale apparaissent comme la résultante de l’équilibre entre dispersion/recrutement de nuages de graines dispersées collectivement, et la compétition pour l’espace entre clones. Les perturbations affectent localement l’équilibre de l’herbier. Cette dynamique originale rend impossible l’identification des contours populationnels. En revanche, nos résultats semblent indiquer que la diversité génétique au sens strict (hétérozygotie et nombre d’allèles) des herbiers de Zostères constitue un facteur de stabilité démographique, via sa potentielle influence sur les capacités de résistance aux perturbations saisonnières. Les coraux d’eau froide, quant à eux, présentent des patrons biogéographiques en accord avec l’hypothèse d’une extinction dans le Golfe de Gascogne, lors des derniers épisodes glaciaires. Les marques visibles des activités de pêche posent la question des capacités de résilience de ces écosystèmes, qui dépendent entre autres du potentiel de dispersion de ces espèces. L’absence de structure génétique observée chez L. pertusa suggère, au moins pour cette espèce, un fort degré d’interconnexion entre les récifs, tandis que M. oculata montre davantage de structure régionale. La sensibilité de ces espèces aux variations climatiques et à la pression des activités anthropiques souligne la nécessité d’études approfondies, pour leur conservation.Les résultats obtenus pendant cette thèse permettent de mieux comprendre la dynamique populationnelle des herbiers et récifs profonds, le taux de clonalité et la connectivité des populations. Ces informations sont essentielles pour avancer vers une meilleure compréhension de la dynamique et la résistance de ces espèces structurantes, et sont donc primordiales pour la conservation de ces écosystèmes clé. / The influence of genetic diversity on the demographic stability of populations constitutes a paradigm in evolutionary ecology. The complexity of this relationship within natural populations is enhanced by the reciprocal effect of stability on diversity, and the degree of interconnection among populations. This interaction was explored within the seagrass Zostera marina and the cold-water corals Lophelia pertusa and Madrepora oculata, three partially clonal species. This life history trait, deeply influencing the population dynamics and evolutionary trajectory of species, constituted the underlying theme of this work.The sampling in space (regional scale) and time (a three-years step) of eelgrass meadows allowed us to better understand the clonal dynamics of these plants. The clonal architecture and diversity may result from the equilibrium between dispersal/recruitment of collectively dispersed clouds of seeds, and the competition for space among clones. Perturbations locally affect the equilibrium of meadows. This original dynamic makes impossible the identification of population contours. Yet, our results suggest that the genetic diversity sensu stricto (heterozygosity and number of alleles) represents a factor of demographic stability, through its putative influence on resistance capacity for seasonal disturbances. Cold-water corals show biogeographic pattern in line with the hypothesis of glacial extinction, within the Bay of Biscay. The noticeable footprints of fishing activities question the capacity of resilience of these ecosystems, depending on dispersal potential of the structuring species, which showed low levels of clonality. The lack of genetic structure observed for L. pertusa suggest, at least for this species, a high degree of interconnection among reefs at large scale, while M. oculata revealed a stronger regional structure. Sensitivity of these two species to climatic variations and the pressures of human activities highlight the need of thorough studies for their conservation. Results obtained during this thesis allow a better understanding of the populations dynamics of both seagrass and deep reefs and their levels of clonality and connectivity. This information constitutes the first step toward a better understanding of dynamics and resistance of these structuring species, and is also primordial for the conservation of their key ecosystems.
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THE ASSOCIATION BETWEEN POLYPLOIDY AND CLONALITY IN THE HERBACEOUS PLANT, CHAMERION ANGUSTIFOLIUM (ONAGRACEAE)

Baldwin, Sarah J 14 May 2012 (has links)
The co-occurrence of polyploidy and clonal reproduction among plant species has long been recognized, but the evolutionary mechanisms underlying the association are unknown. Here, I investigate whether polyploidy increases the magnitude of clonality, either directly or indirectly, by comparing the extent and spatial structure of clones between diploid and tetraploid Chamerion angustifolium in a greenhouse environment and natural populations. In the greenhouse, tetraploid plants allocated 90.4% more dry mass to root buds, the primary mechanism of clonal reproduction, than diploids. Per unit root mass, tetraploids produced 44% fewer root buds and the average position of the root buds along the root was 47% closer to the stem than in diploids. In natural populations, the magnitude of clonality in tetraploid C. angustifolium was similar or less than in diploids. However, clones were spatially aggregated in all diploid populations but only in two of five tetraploid populations. Average clone patch diameter, however, was not significantly different between diploids (3.9 m) and tetraploids (2.5 m). These data do not support the hypothesis that clonality increases as a result of genome duplication. Rather, it is possible that clonality is linked to genome duplication because clonal diploids are predisposed for polyploid formation and establishment. / National Science and Engineering Research Council, Canada Research Chair Program, Canadian Foundation for Innovation
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Análise da integração viral e clonalidade de linfócitos T na dermatite infecciosa associada ao HTLV-1.

Argôlo, Juliana Moreira January 2014 (has links)
Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2015-03-06T16:12:54Z No. of bitstreams: 1 Juliana Moreira Argolo Análise...2014.pdf: 2379371 bytes, checksum: 6533fc64b2d6221825fc83948cfb30eb (MD5) / Approved for entry into archive by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2015-03-06T16:25:11Z (GMT) No. of bitstreams: 1 Juliana Moreira Argolo Análise...2014.pdf: 2379371 bytes, checksum: 6533fc64b2d6221825fc83948cfb30eb (MD5) / Approved for entry into archive by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2015-03-06T16:28:21Z (GMT) No. of bitstreams: 1 Juliana Moreira Argolo Análise...2014.pdf: 2379371 bytes, checksum: 6533fc64b2d6221825fc83948cfb30eb (MD5) / Made available in DSpace on 2015-03-06T16:28:21Z (GMT). No. of bitstreams: 1 Juliana Moreira Argolo Análise...2014.pdf: 2379371 bytes, checksum: 6533fc64b2d6221825fc83948cfb30eb (MD5) Previous issue date: 2014 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / A dermatite infecciosa associada ao vírus linfotrópico de células T humanas tipo 1 (HTLV-1), DIH, é uma forma de eczema grave e recidivante que incide principalmente em crianças que em geral foram verticalmente infectadas pelo HTLV-1, ocorrendo lesões eritematosas, escamativas e crostosas, sendo geralmente localizadas nas regiões do couro cabeludo e retroauriculares, assim como pescoço, virilha, região paranasal, axilas, ouvido externo e narinas. Inicia-se após os 18 meses de vida e raramente persiste até a vida adulta. No Brasil, muitos casos têm sido diagnosticados na Bahia, estado brasileiro que atualmente conta com a maior casuística da literatura depois da Jamaica. Acompanhando uma coorte de 31 pacientes da faixa etária infanto-juvenil com DIH em Salvador, observou-se em esfregaço do sangue periférico, em 11 dos indivíduos, o aparecimento de linfócitos atípicos (LA) e/ou células em flor (CF), que não são comumente observados em pacientes com DIH, mas ocorrem com frequência em pacientes com leucemia/linfoma de células T do adulto (ATL). Submetemos amostras dos 31 pacientes a reações em cadeia da polimerase (PCR) para verificar se havia um clone majoritário através do padrão de clonalidade do TCR-gama. Para este ensaio, todos os 31 pacientes apresentaram padrão oligoclonal ou policlonal típico para DIH, onde não ocorre um clone predominante. A fim de verificar se o aparecimento dos linfócitos atipicos estava relacionado ao possível desenvolvimento da ATL, para os 11 indivíduos que apresentaram os LA e/ou CF em esfregaço do sangue periférico, realizamos ensaios de ILPCR para verificar a clonalidade dos linfócitos infectados pelo vírus e posteriormente sequenciamos as amostras a fim de identificar o local de integração do provírus ao genoma do portador hospedeiro. Em 7 dos 11 indivíduos identificou-se um único clone predominante nos produtos de PCR em pelo menos uma das coletas avaliadas. Nesses casos, o DNA proviral não interrompeu regiões codificadoras para genes humanos. Para um paciente, o provírus se integrou na região do gene da MAP2K1 (proteína quinase 1 ativadora de mitose), localizado no cromossomo 15. Observou-se que na presença de LA e/ou CF podem existir clones majoritários circulantes em portadores do HTLV-1 com DIH. / Infective dermatitis associated with human T lymphotropic cells virus type 1 (HTLV-1), IDH, is a form of severe and recurrent dermatitis that occurs mostly in children who were mainly vertically infected with HTLV-1, occurring erythematous, desquamative and crusty, being generally located in regions of the scalp and retroauricular, neck, groin, paranasal region, armpits, outer ear and nostrils. It begins after 18 months of life and rarely persists into adulthood. In Brazil, several cases have been diagnosed in Bahia, the Brazilian state that currently has the highest incidence after Jamaica. Tracking a cohort of 31 patients in the juvenile age group with IDH in Salvador, we observed the appearance of atypical lymphocytes (AL) and/or flower cells (FC), which are not commonly observed in patients with IDH, but occur frequently in patients with adult T cell leukemia/lymphoma (ATL), in peripheral blood smear in 11 of the subjects. Samples of 31 patients underwent tests of PCR assays to verify if there was a major clone by the clonality patterns of gamma-TCR. For this test, all 31 patients had oligoclonal pattern or typical polyclonal of IDH, where there isn’t a predominant clone. In order to verify if the appearance of the atypical cells was related to the future ATL we submitted the 11 subjects who had the AL and/or FC in peripheral blood smear to ILPCR tests conducted to analyze clonality of lymphocytes infected by the virus and subsequently these samples were sequenced to identify the integrations sites of the provirus in the host-carrier genome. A single dominant clone was observed in the PCR products from at least one of the tested samples in 7 of 11 individuals. In such cases, the proviral DNA did not interrupt coding regions for human gene. For a patient, the provirus was integrated in the region of the MAP2K1 gene (mitosis protein kinase activator 1), located on chromosome 15. We observed that in the presence of AL and/or FC may be majority clones circulating in HTLV- 1 carries with IDH.
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Ecology of alpine plants in NW Himalaya. / Ecology of alpine plants in NW Himalaya.

DVORSKÝ, Miroslav January 2014 (has links)
The westernmost spur of the Tibetan Plateau stretches to Eastern Ladakh in India. It is a region which remains poorly explored because of challenging conditions and long periods of political instability. At the same time, it is one of the highest places on earth supporting angiosperm life, which goes beyond 6000 m a.s.l. here. The whole region, due its remoteness, is practically unaffected by plant invasions and direct human activities. Thus, Ladakh represents a kind of "natural experiment", providing very long gradient of elevation suitable for comparative functional ecology as well as for testing various hypotheses concerning limitations of vascular plants. Arid climate and extreme elevations are the common factors. Our team pursued the goal of systematic botanical and ecological exploration of Ladakh, started by late Leoš Klimeš. This thesis provides insight into the main vegetation types, clonality in plants, plant-plant interactions and soil phototroph communities.
28

Apports de l'étude multiscalaire des dynamiques spatiales des renouées asiatiques (Reynoutria spp.) pour l'amélioration de la gestion / The study of the spatial dynamics of Asian knotweeds (Reynoutria spp.) across scales and its contribution for management improvement

Martin, François-Marie 11 June 2019 (has links)
Bien moins médiatisées que la déforestation ou le changement climatique, les invasions biologiques n’en demeurent pas moins problématiques pour la conservation de nombreux écosystèmes ou le bon déroulement de nombreuses activités socio-économiques.Comprendre la façon dont les espèces exotiques envahissantes s’étendent dans les différents milieux qu’elles colonisent c’est permettre à la fois de mieux appréhender leurs impacts, de pouvoir de prédire leur expansion, et de trouver les endroits stratégiques où agir pour contrer ou atténuer les effets indésirables de ces espèces. Le problème est que dynamiques d’invasions d’une espèce regroupent en fait une hiérarchie de processus se produisant simultanément à différentes échelles spatiotemporelles et qui sont contrôlés par des facteurs qui changent en fonction du temps et du contexte d’invasion. Pour acquérir une compréhension profonde de ces dynamiques, il faut donc étudier leurs manifestations et leurs causes aux diverses échelles spatiales et temporelles auxquelles elles se produisent.Présentes sur les cinq continents et très envahissante sur au moins deux, les renouées asiatiques (Reynoutria spp.) sont reconnues comme faisant partie des espèces les plus invasives de la planète. Dotées d’une grande tolérance environnementale et d’importantes capacités de multiplication végétatives, ces plantes herbacées géantes peuvent former rapidement de grandes monocultures clonales qui excluent les autres espèces végétales, modifient les cycles biogéochimiques des zones envahies et perturbent diverses activités anthropiques. Cibles de campagnes de gestion depuis des décennies, elles affichent cependant une résilience insolente qui désespère de nombreux gestionnaires. Bien que très étudiées, de nombreux détails concernant leurs dynamiques nous échappent toujours. Dans ce travail de thèse, nous avons donc cherché à identifier quels sont les facteurs qui contrôlent les dynamiques spatiotemporelles des renouées à différentes échelles, et comment une meilleure compréhension de ces dynamiques clés pourrait profiter à leur gestion ?Pour ce faire, nous nous sommes donc d’abord intéressés à leur dynamiques clonales et à leurs variations en fonction de différentes conditions de stress (ombrage) ou de perturbation (fauchage répétée). Nous avons montré que si les renouées sont bien affectées par des conditions stressantes ou perturbées, cela ne les empêche ni de s’établir, ni de croître. En fait, les renouées semblent pouvoir adopter différentes stratégies de croissance pour pallier ces contraintes, soulevant différentes questions liées à la gestion. Dans une deuxième étude, nous avons cherché quels étaient les variables qui expliquaient l’expansion des taches de renouées le long d’un gradient altitudinal. Si nous avons montré que les dynamiques d’expansion des taches étaient principalement contrôlées par leur taille (et donc potentiellement leur âge) ainsi que par la proximité de routes et de rivières, nous avons également apporté des indices qui suggèrent que les renouées pourraient être potentiellement capables d’envahir les montagnes. Ensuite, pour tenter d’aider à résoudre le problème de l’acquisition des données de distribution des renouées à large échelle, nous avons développé une méthode pour détecter et cartographier les populations de renouées à partir d’images satellites et issues de drones. Notre méthode a montré des résultats encourageants et celle-ci pourrait être utile à l’étude des invasions ainsi qu’à la détection des nouveaux foyers d’invasion pour une gestion plus précoce et efficace des renouées.Enfin, nous avons tenté de dresser un portrait global de la compréhension actuelle des dynamiques d’invasion des renouées en réalisant, en guise de discussion, une grande revue de littérature sur les mouvements de ces plantes à travers les échelles spatiales et temporelles et en y intégrant les apports des autres travaux de cette thèse. / Although less mediatized than deforestation or climate change, biological invasions remain problematic for the conservation of many ecosystems and the maintenance of various socio-economical activities.Understanding the way invasive non-native species spread in their introduced range is enabling a better apprehension of their impacts, the possibility to predict their expansion, and the development of better management strategies. A problem is that a species invasion dynamics are actually composed of a hierarchy of processes occurring simultaneously at various spatiotemporal scales and which are controlled by drivers that are time- or context-dependent. To gain more profound insights into these dynamics, one has to study the patterns they create and their underlying processes at all relevant scales.Occurring on the five continents and highly invasive on at least two of them, Asian knotweeds (Reynoutria spp.) are acknowledged as being among the most invasive species in the world. Gifted with a large environmental tolerance and high abilities for vegetative multiplication, these giant herbaceous plants can quickly form large clonal monocultures that exclude the other plant species, modify biogeochemical cycles, and affect various anthropic activities. Target of management campaigns for decades, knotweeds display an insolent resilience to the great despair of many stakeholders. Despite having been extensively studied, many aspects of their dynamics are still elusive. Consequently, in this thesis, we have tried to highlight what the drivers of the spatiotemporal dynamics of knotweeds across scales are, and how their management could benefit from a better understanding of these dynamics?To answer these questions, we first focused our attention on the clonal dynamics of knotweeds and on their variations when they experience differing conditions in terms of light availability and disturbance (repeated mowing). We have shown that although shade or mowing affects the vigour and the development of clones, it does not prevent their establishment or their growth. In fact, knotweeds seem able to adopt different growth strategies to cope with environmental heterogeneity, suggesting some management avenues. In a second study, we tried to identify the drivers that controlled the expansion of knotweed stands along an elevational gradient. If we showed that the lateral expansion of stands is mostly constrained by their size (and thus, possibly their age) and the vicinity of roads and rivers, we also brought evidences that knotweeds could have the potential to invade mountain regions. Then, to help for the acquisition of large-scale datasets on knotweeds’ distribution, we developed a procedure to accurately detect and map knotweeds using satellite or drone imagery. Our results were quite encouraging and could be useful to both the basic research and to the detection of newly invaded areas, enabling earlier control operations and more efficient management.Finally, we tried to draw a full picture of the current knowledge on the invasion dynamics of knotweeds by reviewing the literature on the movement of these plants across spatial and temporal scales, to discuss and expand the reach of the insights gained in the various chapters of this thesis.
29

Caracterização genética e perfil de sensibilidade antimicrobiana de cepas multirresistentes de Acinetobacter baumannii presentes em um hospital de ensino / Genetic characterization and antimicrobial susceptibility profile of multiresistant Acinetobacter baumannii strains present at a teaching hospital

Tavares, Laís Calissi Brisolla 07 February 2018 (has links)
As espécies do Complexo Acinetobacter calcoaceticus-A. baumannii (ACB) são importantes causadoras de Infecções Relacionadas à Assistência à Saúde em todo o mundo. Detêm maior relevância os isolados com resistência aos antimicrobianos, os quais impactam negativamente no prognóstico, na mortalidade e custos associados ao cuidado com o paciente. O objetivo deste estudo foi avaliar a diversidade genética e o perfil de susceptibilidade antimicrobiana de 134 isolados multirresistentes de A. baumannii presentes no Hospital das Clínicas da Faculdade de Medicina de Botucatu, entre 2007 e 2014. A identificação de A. baumannii deu-se pela pesquisa dos genes blaOXA-51-like e gltA, detectados em 85% (n=114) dos isolados Os isolados de Acinetobacter não-baumannii foram identificados por sequenciamento gênico como A. nosocomialis (n=4; 3,1%), A. pittii, A. bereziniae (n=2; 1,7%, cada), A. ursingii, A. variabilis, A. gyllenbergii (n=1; 0,9% cada) e Acinetobacter spp (n=2; 1,7%). Os isolados de A. baumannii foram submetidos às técnicas de PCR multiplex para detecção de outras oxacilinases, pesquisa de ISAba1, teste de susceptibilidade antimicrobiana, tipagem molecular por eletroforese em campo pulsado (PFGE), por sequência trilocus (3LST) e por sequência multilocus (MLST). Detectou-se o gene blaOXA-23-like em 105 isolados (92,1%), estando 100% associados a ISAba1; blaOXA-72 em um isolado (0,9%) e blaOXA-231 em dois isolados (1,7%). A maior parte (n=66; 57,9%) dos isolados foi classificada como extensivamente resistentes (XDR). O PFGE agrupou os isolados em 11 clusters (A-K) e o MLST identificou os isolados pertencentes majoritariamente aos clones CC79 (42,4%), CC1 (16,6%), CC15 (12,1%) e ao ST317 (18,2%). Os resultados do MLST e 3LST concordaram em 95,6%. Foi verificada a ocorrência de diferentes perfis de PFGE em A. baumannii MDR e XDR, predominando cepas carreadoras de ISAba1/OXA-23-like e pertencentes aos CC1, CC15, CC79, ST317. Predominaram o ST317 nos anos iniciais e o CC79 (ST730) de 2011 a 2014. Estes resultados fornecem subsídios que ressaltam a necessidade de monitoramento e controle de patógenos multirresistentes / Species of Acinetobacter calcoaceticus-A. baumannii Complex (ACB) are important causes of Healthcare Associated Infections worldwide. More relevant are isolates with antimicrobial resistance, which have a negative impact on the outcome, mortality and costs associated with patient care. The aim of this study was to evaluate the genetic diversity and the antimicrobial susceptibility profile of 134 multiresistant ACB spcies strains present at Botucatu Medical School Teaching Hospital between 2007 and 2014. Identification of A. baumannii species was by detection of blaOXA-51-like and gltA genes, detected in 85% (n=114) of the isolates. Non-baumannii Acinetobacter species were identified by gene sequencing as A. nosocomialis (n=4, 3.1%), A. ursingii, A. variabilis, A. gyllenbergii (n=1, 0.9% each) and Acinetobacter spp (n=2; 1.7%). A. baumannii isolates were submitted to multiplex PCR for other oxacillinases and ISAba1 detection, antimicrobial susceptibility testing, molecular typing by pulsed field gel electrophoresis (PFGE), trilocus sequence typing (3LST) and multilocus sequence typing (MLST). blaOXA-23-like gene was detected in 105 isolates (92.1%), of which 100% were associated with ISAba1; blaOXA-72 was present in one isolate (0.9%) and blaOXA-231, in two isolates (1.7%). The majority (n=66; 57.9%) of isolates were classified as extensively resistant (XDR). The PFGE grouped the isolates into 11 clusters (A-K) and MLST identified the isolates belonging mainly to CC79 (42.4%), CC1 (16.6%), CC15 (12.1%) and ST317 (18.2%). MLST and 3LST results were 95.6% concordant. We verified the occurrence of different PFGE profiles in multidrug-resistant (MDR) and extensively drug-resistant (XDR) A. baumannii, predominantly presenting ISAba1/OXA-23-like genes and belonging to CC1, CC15, CC79 and ST317. There was a prevalence of ST317 in the early years and CC79 (ST730) from 2011 to 2014. Our results highlight the importance of surveillance and control of multiresistant pathogens
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Caracterização genética e perfil de sensibilidade antimicrobiana de cepas multirresistentes de Acinetobacter baumannii presentes em um hospital de ensino / Genetic characterization and antimicrobial susceptibility profile of multiresistant Acinetobacter baumannii strains present at a teaching hospital

Laís Calissi Brisolla Tavares 07 February 2018 (has links)
As espécies do Complexo Acinetobacter calcoaceticus-A. baumannii (ACB) são importantes causadoras de Infecções Relacionadas à Assistência à Saúde em todo o mundo. Detêm maior relevância os isolados com resistência aos antimicrobianos, os quais impactam negativamente no prognóstico, na mortalidade e custos associados ao cuidado com o paciente. O objetivo deste estudo foi avaliar a diversidade genética e o perfil de susceptibilidade antimicrobiana de 134 isolados multirresistentes de A. baumannii presentes no Hospital das Clínicas da Faculdade de Medicina de Botucatu, entre 2007 e 2014. A identificação de A. baumannii deu-se pela pesquisa dos genes blaOXA-51-like e gltA, detectados em 85% (n=114) dos isolados Os isolados de Acinetobacter não-baumannii foram identificados por sequenciamento gênico como A. nosocomialis (n=4; 3,1%), A. pittii, A. bereziniae (n=2; 1,7%, cada), A. ursingii, A. variabilis, A. gyllenbergii (n=1; 0,9% cada) e Acinetobacter spp (n=2; 1,7%). Os isolados de A. baumannii foram submetidos às técnicas de PCR multiplex para detecção de outras oxacilinases, pesquisa de ISAba1, teste de susceptibilidade antimicrobiana, tipagem molecular por eletroforese em campo pulsado (PFGE), por sequência trilocus (3LST) e por sequência multilocus (MLST). Detectou-se o gene blaOXA-23-like em 105 isolados (92,1%), estando 100% associados a ISAba1; blaOXA-72 em um isolado (0,9%) e blaOXA-231 em dois isolados (1,7%). A maior parte (n=66; 57,9%) dos isolados foi classificada como extensivamente resistentes (XDR). O PFGE agrupou os isolados em 11 clusters (A-K) e o MLST identificou os isolados pertencentes majoritariamente aos clones CC79 (42,4%), CC1 (16,6%), CC15 (12,1%) e ao ST317 (18,2%). Os resultados do MLST e 3LST concordaram em 95,6%. Foi verificada a ocorrência de diferentes perfis de PFGE em A. baumannii MDR e XDR, predominando cepas carreadoras de ISAba1/OXA-23-like e pertencentes aos CC1, CC15, CC79, ST317. Predominaram o ST317 nos anos iniciais e o CC79 (ST730) de 2011 a 2014. Estes resultados fornecem subsídios que ressaltam a necessidade de monitoramento e controle de patógenos multirresistentes / Species of Acinetobacter calcoaceticus-A. baumannii Complex (ACB) are important causes of Healthcare Associated Infections worldwide. More relevant are isolates with antimicrobial resistance, which have a negative impact on the outcome, mortality and costs associated with patient care. The aim of this study was to evaluate the genetic diversity and the antimicrobial susceptibility profile of 134 multiresistant ACB spcies strains present at Botucatu Medical School Teaching Hospital between 2007 and 2014. Identification of A. baumannii species was by detection of blaOXA-51-like and gltA genes, detected in 85% (n=114) of the isolates. Non-baumannii Acinetobacter species were identified by gene sequencing as A. nosocomialis (n=4, 3.1%), A. ursingii, A. variabilis, A. gyllenbergii (n=1, 0.9% each) and Acinetobacter spp (n=2; 1.7%). A. baumannii isolates were submitted to multiplex PCR for other oxacillinases and ISAba1 detection, antimicrobial susceptibility testing, molecular typing by pulsed field gel electrophoresis (PFGE), trilocus sequence typing (3LST) and multilocus sequence typing (MLST). blaOXA-23-like gene was detected in 105 isolates (92.1%), of which 100% were associated with ISAba1; blaOXA-72 was present in one isolate (0.9%) and blaOXA-231, in two isolates (1.7%). The majority (n=66; 57.9%) of isolates were classified as extensively resistant (XDR). The PFGE grouped the isolates into 11 clusters (A-K) and MLST identified the isolates belonging mainly to CC79 (42.4%), CC1 (16.6%), CC15 (12.1%) and ST317 (18.2%). MLST and 3LST results were 95.6% concordant. We verified the occurrence of different PFGE profiles in multidrug-resistant (MDR) and extensively drug-resistant (XDR) A. baumannii, predominantly presenting ISAba1/OXA-23-like genes and belonging to CC1, CC15, CC79 and ST317. There was a prevalence of ST317 in the early years and CC79 (ST730) from 2011 to 2014. Our results highlight the importance of surveillance and control of multiresistant pathogens

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