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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.
1

Phylogeographic Variation of Siberian Weasel (Mustela sibirica) in Taiwan, Based on Control Region Sequences of Mitochondrial DNA.

Wu, Ming-Chin 05 September 2004 (has links)
Siberian weasel, Mustela sibirica is a widespread carnivora mammal in Eurasia. In Taiwan, it inhabits a variety of environments restricted to altitude above 800 m. Based on mitochondrial control region sequences, I constructed phylogeography and analyzed population interflow about the species in Taiwan. The mean length of D-loop in Siberian weasel is 1038.9 bp. The D-loop structure can be divided into ETAS, CD and CSB domain. Among these, CD is the most conserved region while the two flank domains are variable. There are tandem repeat sequences in CSB domain, common in other carnivores. In phylogenetic analyses, three major lineages were found in phylogenetic trees and MSN topology. In general, haplotypes in clades are correlated to geographic distribution. The haplotypes of clade I were sampled from southern Taiwan, while the majority of those clade II and clade III were from northern Taiwan. The gene flow among clades were low. However no significant geographic boundaries existed between clades. It is speculated that the genetic isolation among clades may have been resulted from bottleneck effect, like other high altitude mammals in Taiwan, and not from geographic barriers mainly.
2

Intraspecific Phylogeography of Cycladenia humilis (Apocynaceae)

Last, Mariana P. 10 November 2009 (has links) (PDF)
Cycladenia humilis (Apocynaceae) is a rare perennial herb native to western North America and has a fragmented distribution in California, Utah, and Arizona. Populations in Utah and Arizona are federally listed as threatened, while there is no conservation status applied to California populations. Using genetic (three chloroplast and two nuclear DNA loci) and morphological characters, intraspecific variation between populations of C. humilis and current taxonomic conventions were assessed. Nested Clade Phylogeographic Analysis and Bayesian phylogenies were used to assess patterns within C. humilis and supported three main population groupings: a northern California, southern California, and Colorado Plateau group. The northern California populations represent a distinct group and include populations from the Santa Lucia Mountains contrary to current classifications. The southern California group consistently includes populations in the San Gabriel and Inyo Mountains and was unique from any other region. The Colorado Plateau represents a group distinct from all other groups. The resilience of C. humilis on the Colorado Plateau to human threats remains unknown, but based on its frequency being comparable to California and our findings that considerable genetic variation exists within the species and within populations on the Colorado Plateau, we recommend that the threatened status of C. humilis be lifted.
3

Phylogenetic and Phylogeographic Studies of Panstrongylus sp., Vectors of Chagas Disease in Loja and Manabí Provinces, Ecuador

Sempertegui-Sosa, Carolina 11 September 2012 (has links)
No description available.
4

Estudo evolutivo dos hantavírus e desenvolvimento de uma RT-PCR quantitativa em tempo real para detecção do vírus Araraquara / Evolutionary study of Hantavirus and development of a quantitative real time RT-PCR for detection of Araraquara virus

Souza, William Marciel de 28 March 2013 (has links)
O gênero Hantavírus está incluído na família Bunyaviridae que são vírus emergentes associados a roedores que podem infectar o homem causando graves doenças. Nas Américas, os Hantavírus causam uma síndrome pulmonar e cardiovascular (SPCVH) com alta letalidade. Cerca de 1600 casos de SPCVH já foram notificados no Brasil causando mais de 600 óbitos. Sete espécies de Hantavírus são conhecidas no Brasil incluindo o vírus Araraquara que circula nas regiões de cerrado do país associado ao roedor Necromys lasiurus. Para o desenvolvimento de uma RT-PCR em tempo real para detecção e quantificação de Hantavírus, mostramos as etapas para o desenvolvimento de uma one-step RT-PCR em tempo real SYBR Green I para Hantavírus Araraquara que se mostrou específica para o gênero e capaz de detectar até 10 cópias por mL de RNA viral na amostra. Além disso, realizamos um estudo filogenético utilizando algoritmos bayesianos, com 190 sequências completas do gene da nucleoproteína, oriundas de 30 países durante um período de 25 anos (1985-2010) que encontravam-se disponíveis no GenBank (NCBI). Baseando-se em uma taxa média de 6.8 x 10-4 (2.5 x 10-4 - 1 x 10-3) substituições nucleotídicas por sítio/ano, foi possível inferir que os Hantavírus teriam aproximadamente 1917 anos. O processo de dispersão dos Hantavírus pelo mundo teria ocorrido há aproximadamente 500 anos, e a introdução destes vírus nas Américas teria ocorrido há 549 anos (95% HPD 1555-341 anos), via América Central ou México, originando os Hantavírus adaptados aos roedores da subfamília Neotominae, e pelo Brasil surgindo há 406 anos (95% HPD 1150-250 anos) os Hantavírus associados a roedores da subfamília Sigmodontinae, e posteriormente dispersaram para todo o continente sul-americano. O trabalho contribui de forma relevante para o diagnóstico das infecções por Hantavírus com a one-step RT-PCR em tempo real SYBR Green I e também, contribui para o entendimento da filogenia e história destes vírus, oferecendo subsídios ao entendimento sobre como teria ocorrido o espalhamento dos Hantavírus pelo mundo. / The genus Hantavirus is included in the family Bunyaviridae are viruses emerging carried by rodents, which can infect humans causing serious illness. In the Americas, the Hantavirus causing a pulmonary syndrome (HPS) with high lethality. About 1,600 cases of HPS have been reported in Brazil, cause over 1600 deaths. Seven species of Hantavirus are known in Brazil, including Araraquara virus circulating in Cerrado regions (or Savannah regions) of the related in rodents Necromys lasiurus. The development of a real-time RT-PCR for detection and quantitation of Araraquara virus, here we show the steps for developing a one-step SYBR Green real-time RT-PCR for virus Araraquara which proved to be specific for the genus and capable of detecting up to 10 copies of viral RNA per ml in the sample. Furthemore, we performed a phylogenetic analysis using Bayesian algorithms, with 190 complete sequences of the nucleoprotein gene, originating from 30 countries over a 25 year period (1985-2010) that were available in GenBank (NCBI). Based on an average rate of 6.8 x 10-4 (2.5 x 10-4 - 1 x 10-3) nucleotide substitutions per site/year, it was possible to infer that the Hantavirus would be about 1917 years old. The Hantavirus spreading in the world have occurred for nearly 500 years, and the introduction of these viruses have occurred in the Americas 549 years ago (95 years% HPD 1555-341) bye Central America or Mexico, causing the Hantavirus adapted to rodents subfamily Neotominae, and Brazil emerged 406 years ago (95% HPD 1150-250 years) the Hantavirus associated with rodents subfamily Sigmodontinae, and subsequently disseminated to South America. The work contributes significantly to the diagnosis of Hantavirus infections with one-step SYBR Green real-time RT-PCR and also contributes to an understanding of the phylogeny and evolutionary history of these viruses, offering subsidies have occurred understanding of how the Hantavirus spread of the worldwide.
5

Estudo evolutivo dos hantavírus e desenvolvimento de uma RT-PCR quantitativa em tempo real para detecção do vírus Araraquara / Evolutionary study of Hantavirus and development of a quantitative real time RT-PCR for detection of Araraquara virus

William Marciel de Souza 28 March 2013 (has links)
O gênero Hantavírus está incluído na família Bunyaviridae que são vírus emergentes associados a roedores que podem infectar o homem causando graves doenças. Nas Américas, os Hantavírus causam uma síndrome pulmonar e cardiovascular (SPCVH) com alta letalidade. Cerca de 1600 casos de SPCVH já foram notificados no Brasil causando mais de 600 óbitos. Sete espécies de Hantavírus são conhecidas no Brasil incluindo o vírus Araraquara que circula nas regiões de cerrado do país associado ao roedor Necromys lasiurus. Para o desenvolvimento de uma RT-PCR em tempo real para detecção e quantificação de Hantavírus, mostramos as etapas para o desenvolvimento de uma one-step RT-PCR em tempo real SYBR Green I para Hantavírus Araraquara que se mostrou específica para o gênero e capaz de detectar até 10 cópias por mL de RNA viral na amostra. Além disso, realizamos um estudo filogenético utilizando algoritmos bayesianos, com 190 sequências completas do gene da nucleoproteína, oriundas de 30 países durante um período de 25 anos (1985-2010) que encontravam-se disponíveis no GenBank (NCBI). Baseando-se em uma taxa média de 6.8 x 10-4 (2.5 x 10-4 - 1 x 10-3) substituições nucleotídicas por sítio/ano, foi possível inferir que os Hantavírus teriam aproximadamente 1917 anos. O processo de dispersão dos Hantavírus pelo mundo teria ocorrido há aproximadamente 500 anos, e a introdução destes vírus nas Américas teria ocorrido há 549 anos (95% HPD 1555-341 anos), via América Central ou México, originando os Hantavírus adaptados aos roedores da subfamília Neotominae, e pelo Brasil surgindo há 406 anos (95% HPD 1150-250 anos) os Hantavírus associados a roedores da subfamília Sigmodontinae, e posteriormente dispersaram para todo o continente sul-americano. O trabalho contribui de forma relevante para o diagnóstico das infecções por Hantavírus com a one-step RT-PCR em tempo real SYBR Green I e também, contribui para o entendimento da filogenia e história destes vírus, oferecendo subsídios ao entendimento sobre como teria ocorrido o espalhamento dos Hantavírus pelo mundo. / The genus Hantavirus is included in the family Bunyaviridae are viruses emerging carried by rodents, which can infect humans causing serious illness. In the Americas, the Hantavirus causing a pulmonary syndrome (HPS) with high lethality. About 1,600 cases of HPS have been reported in Brazil, cause over 1600 deaths. Seven species of Hantavirus are known in Brazil, including Araraquara virus circulating in Cerrado regions (or Savannah regions) of the related in rodents Necromys lasiurus. The development of a real-time RT-PCR for detection and quantitation of Araraquara virus, here we show the steps for developing a one-step SYBR Green real-time RT-PCR for virus Araraquara which proved to be specific for the genus and capable of detecting up to 10 copies of viral RNA per ml in the sample. Furthemore, we performed a phylogenetic analysis using Bayesian algorithms, with 190 complete sequences of the nucleoprotein gene, originating from 30 countries over a 25 year period (1985-2010) that were available in GenBank (NCBI). Based on an average rate of 6.8 x 10-4 (2.5 x 10-4 - 1 x 10-3) nucleotide substitutions per site/year, it was possible to infer that the Hantavirus would be about 1917 years old. The Hantavirus spreading in the world have occurred for nearly 500 years, and the introduction of these viruses have occurred in the Americas 549 years ago (95 years% HPD 1555-341) bye Central America or Mexico, causing the Hantavirus adapted to rodents subfamily Neotominae, and Brazil emerged 406 years ago (95% HPD 1150-250 years) the Hantavirus associated with rodents subfamily Sigmodontinae, and subsequently disseminated to South America. The work contributes significantly to the diagnosis of Hantavirus infections with one-step SYBR Green real-time RT-PCR and also contributes to an understanding of the phylogeny and evolutionary history of these viruses, offering subsidies have occurred understanding of how the Hantavirus spread of the worldwide.
6

Filogeografia da febre amarela na América do Sul / Phylogeography of the Yellow Fever in South America

Souza, Renato Pereira de 11 April 2013 (has links)
Os Flavivírus são vírus de 40 50 nm de diâmetro, com formas esféricas e RNA de fita simples, com sentido positivo e aproximadamente 11 kb de comprimento. O Vírus da Febre Amarela, protótipo do grupo, é o agente causador da Febre Amarela, uma antiga doença que causou epidemias generalizadas na África, Américas do Norte e do Sul e Europa do século XVII ao início do século XX, e depois ressurgiu nas últimas décadas na África sub- saariana e América do Sul tropical. O presente trabalho busca a reconstrução da transmissão da Febre Amarela na América do Sul, no tempo e espaço, em especial, considerando a provável influência das populações humanas, primatas não humanos e mosquitos, na evolução e distribuição das linhagens genéticas de Febre Amarela, aplicando modelos de inferência Bayesiana para análises filogenéticas e filogeográficas e testando hipóteses de distribuição geográfica com modelagem de nicho ecológico. Os dados dão poucas evidências de que as estratégias de vacinação vigentes tenham efetivamente colaborado para a diminuição da ocorrência de Febre Amarela, indicando possíveis erros na estratégia de vacinação. A partir da análise Coalescente da população viral de Febre Amarela, a população viral apresentou um decréscimo importante iniciado em meados dos anos 90. A análise filogeográfica sugere um padrão geral de transmissibilidade Source-Sink destacando a região amazônica como fonte de diversidade para as outras áreas estudadas, com uma estrutura filogeográfica secundária em ondas. Assim, as introduções do vírus em áreas fora da amazônia tem ocorrência aleatória e podem ser ligadas temporalmente e geograficamente ao norte da America do Sul. Os modelos de distribuição geográfica corroboram esse padrão e indicam uma área possível para circulação da Febre Amarela ampla, englobando diversos ecótonos. Os resultados indicam um possível efeito em longo prazo da vacinação atuando diretamente sobre a evolução e dinâmica filogenética da Febre Amarela e sugere que monitorar a evolução do vírus da Febre Amarela é uma estratégia válida para compreender sua distribuição geográfica e evidenciar mecanismos complexos de transmissão e introdução. Por sua vez, os modelos de Nicho Ecológico mostraram ser ferramentas adequadas para calcular o risco da doença em determinadas áreas, sem sua ocorrência prévia, contribuindo como um modelo preditivos para orgãos de Vigilância prepararem suas estratégias de prevenção e controle no caso de possível introdução de patógenos / The flaviviruses are viruses of 40-50 nm in diameter, with spherical shaped and single-strand RNA with positive sense and approximately 11 kb in length. The Yellow Fever virus is the prototype of the group and the causative agent of Yellow Fever, a disease which caused widespread epidemics in Africa, North America, South America and Europe of the seventeenth century to the early twentieth century. The disease reemerged in recent decades in sub-Saharan Africa and tropical South America. This manuscript aims to reconstruct, in time and space, the transmission of yellow fever in South America, through the applying of a Bayesian inference model, considering the probable influence of human populations, nonhuman primates and mosquitoes on the evolution and distribution of Yellow Fever genetic lineages. Distributional pattern hypothesis will be tested by computational modeling of ecological niche. The data provide little evidence that current vaccination strategies have effectively contributed to reducing the occurrence of Yellow Fever, indicating possible errors in the vaccination strategy. From the analysis of the Yellow Fever population Coalescence, the viral population showed a significant decrease started in the mid-90s. The phylogeographic analysis suggests a general pattern of transmissibility \"Source-Sink\" highlighting the Amazon region as a source of diversity for the other areas studied, with a secondary phylogeographic wave like structure. Thus, the introductions of the virus into areas outside the Amazon has random occurrence and can be linked temporally and geographically to the north of South America The geographical distribution models corroborate this pattern and indicate a broad possible area for Yellow Fever circulation, encompassing many ecotones. The results indicate a possible long-term effect of vaccination acting directly on the evolution and phylogenetic dynamics of Yellow Fever and suggests that monitoring the evolution of the Yellow Fever virus is a valid strategy to understand the geographical distribution and highlight complex transmission mechanisms and spatial movements. In turn Ecological Niche models showed as an appropriate tool to calculate disease risk in certain areas without previous occurrence of the disease, working as a predictive model for Surveillance institutions prepare their strategies for prevention and control in the case of possible pathogen introduction
7

Development of broodstock management and husbandry tools for improved hatchery performance of ballan wrasse (Labrus bergylta)

Grant, Bridie January 2016 (has links)
Cleaner fish, including ballan wrasse (Labrus bergylta) have been proposed as a sustainable solution to sea lice infestations affecting farmed Atlantic salmon (Salmo salar) globally. However, in order to become sustainable, ballan wrasse need to be farmed. This thesis investigated the establishment of captive broodstock and protocols to optimise hatchery performance and productivity of ballan wrasse. High throughput sequencing was used to develop a panel of novel single nucleotide polymorphic markers (SNPs). These SNPs were used to investigate the phylogeographic structuring of ballan wrasse populations within northern geographic ranges including the UK and Norway. Results indicated fine scale population structuring within the UK suggesting that founder broodstock should be sourced locally to minimise the risk of genetic introgression with wild ballan wrasse. Secondly, captive breeding was benchmarked from harems to determine total egg production over the spawning season. Data quantified the spawning periodicity and seasonal changes in egg quality parameters. In addition, microsatellite markers identified the parental contribution to each spawning event of captive broodstock. Results confirmed, for the first time, the repeat-batch spawning behaviour and suggested that spawning events were single-paired matings. Furthermore, bottlenecks in commercial production were investigated including the benthic adhesive eggs and complex spawning behaviours of ballan wrasse within broodstock tanks. Experiments were conducted to optimise the spawning dynamics and egg productivity using fragmented spawning zones and coloured substrates. Finally, an effective bath treatment for removal of the adhesive gum layer of eggs using the proteolytic enzyme alcalase® was found to assist in egg disinfection and incubation. Overall, this research provides important baseline data on the management of broodstock and the optimisation of hatchery protocols to improve the commercial productivity and performance of ballan wrasse for use as a biological control of sea lice of farmed Atlantic salmon.
8

Filogeografia da febre amarela na América do Sul / Phylogeography of the Yellow Fever in South America

Renato Pereira de Souza 11 April 2013 (has links)
Os Flavivírus são vírus de 40 50 nm de diâmetro, com formas esféricas e RNA de fita simples, com sentido positivo e aproximadamente 11 kb de comprimento. O Vírus da Febre Amarela, protótipo do grupo, é o agente causador da Febre Amarela, uma antiga doença que causou epidemias generalizadas na África, Américas do Norte e do Sul e Europa do século XVII ao início do século XX, e depois ressurgiu nas últimas décadas na África sub- saariana e América do Sul tropical. O presente trabalho busca a reconstrução da transmissão da Febre Amarela na América do Sul, no tempo e espaço, em especial, considerando a provável influência das populações humanas, primatas não humanos e mosquitos, na evolução e distribuição das linhagens genéticas de Febre Amarela, aplicando modelos de inferência Bayesiana para análises filogenéticas e filogeográficas e testando hipóteses de distribuição geográfica com modelagem de nicho ecológico. Os dados dão poucas evidências de que as estratégias de vacinação vigentes tenham efetivamente colaborado para a diminuição da ocorrência de Febre Amarela, indicando possíveis erros na estratégia de vacinação. A partir da análise Coalescente da população viral de Febre Amarela, a população viral apresentou um decréscimo importante iniciado em meados dos anos 90. A análise filogeográfica sugere um padrão geral de transmissibilidade Source-Sink destacando a região amazônica como fonte de diversidade para as outras áreas estudadas, com uma estrutura filogeográfica secundária em ondas. Assim, as introduções do vírus em áreas fora da amazônia tem ocorrência aleatória e podem ser ligadas temporalmente e geograficamente ao norte da America do Sul. Os modelos de distribuição geográfica corroboram esse padrão e indicam uma área possível para circulação da Febre Amarela ampla, englobando diversos ecótonos. Os resultados indicam um possível efeito em longo prazo da vacinação atuando diretamente sobre a evolução e dinâmica filogenética da Febre Amarela e sugere que monitorar a evolução do vírus da Febre Amarela é uma estratégia válida para compreender sua distribuição geográfica e evidenciar mecanismos complexos de transmissão e introdução. Por sua vez, os modelos de Nicho Ecológico mostraram ser ferramentas adequadas para calcular o risco da doença em determinadas áreas, sem sua ocorrência prévia, contribuindo como um modelo preditivos para orgãos de Vigilância prepararem suas estratégias de prevenção e controle no caso de possível introdução de patógenos / The flaviviruses are viruses of 40-50 nm in diameter, with spherical shaped and single-strand RNA with positive sense and approximately 11 kb in length. The Yellow Fever virus is the prototype of the group and the causative agent of Yellow Fever, a disease which caused widespread epidemics in Africa, North America, South America and Europe of the seventeenth century to the early twentieth century. The disease reemerged in recent decades in sub-Saharan Africa and tropical South America. This manuscript aims to reconstruct, in time and space, the transmission of yellow fever in South America, through the applying of a Bayesian inference model, considering the probable influence of human populations, nonhuman primates and mosquitoes on the evolution and distribution of Yellow Fever genetic lineages. Distributional pattern hypothesis will be tested by computational modeling of ecological niche. The data provide little evidence that current vaccination strategies have effectively contributed to reducing the occurrence of Yellow Fever, indicating possible errors in the vaccination strategy. From the analysis of the Yellow Fever population Coalescence, the viral population showed a significant decrease started in the mid-90s. The phylogeographic analysis suggests a general pattern of transmissibility \"Source-Sink\" highlighting the Amazon region as a source of diversity for the other areas studied, with a secondary phylogeographic wave like structure. Thus, the introductions of the virus into areas outside the Amazon has random occurrence and can be linked temporally and geographically to the north of South America The geographical distribution models corroborate this pattern and indicate a broad possible area for Yellow Fever circulation, encompassing many ecotones. The results indicate a possible long-term effect of vaccination acting directly on the evolution and phylogenetic dynamics of Yellow Fever and suggests that monitoring the evolution of the Yellow Fever virus is a valid strategy to understand the geographical distribution and highlight complex transmission mechanisms and spatial movements. In turn Ecological Niche models showed as an appropriate tool to calculate disease risk in certain areas without previous occurrence of the disease, working as a predictive model for Surveillance institutions prepare their strategies for prevention and control in the case of possible pathogen introduction
9

Diversité et structuration génétique des sapotacées endémiques de l'archipel des Mascareignes à différentes échelles spatiales et temporelles / Diversity and genetic struture of endemic Sapotaceae from Mascarene archipelago at different spatial and temporal scales

Dafreville, Stéphanie 08 November 2013 (has links)
L'archipel des Mascareignes (Réunion, Maurice et Rodrigues) est, avec les Seychelles, les Comores et Madagascar, l'un des 34 « hotspots » de biodiversité reconnus à l'échelle mondiale. Dans un contexte de disparition des habitats par les activités humaines, l'objectif de la thèse a été de comprendre la dynamique évolutive à différentes échelles spatiales et temporelles d'une famille d'espèces indigènes des écosystèmes forestiers, les Sapotacées. Ces espèces arborées présentent une gamme diversifiée de niveaux d’endémisme, d'abondance, de modes de régénération et de caractéristiques biologiques. La famille des Sapotacées comprend 3 genres et 14 espèces indigènes des Mascareignes (Mimusops, Labourdonnaisia et Sideroxylon) dont certaines espèces, rares et protégées, sont endémiques d'une des trois îles de l'archipel des Mascareignes. À l'échelle de la famille, l'analyse des séquences chloroplastiques de la famille des Sapotacées a confirmé la forte différenciation entre genres avec deux clades. Le premier clade est constitué par toutes les espèces de Sideroxylon structurées en trois sous-clades distincts dont deux correspondent aux sections Eusideroxylon et Calvaria, montrant une diversité haplotypique importante. Le deuxième clade est constitué par deux sous-clades formés respectivement par les espèces de Labourdonnaisia et celles de Mimusops. Alors qu'il n'est pas possible de résoudre les relations de parenté des Mimusops, Labourdonnaisia présentent deux lignées évolutives soulevant une incongruence entre les données taxonomiques et phylogénétiques. À l'échelle des deux lignées du genre Sideroxylon (Sections Eusideroxylon et Calvaria), l'analyse des marqueurs microsatellites chloroplastiques a montré une forte diversité haplotypique à la fois chez des espèces communes comme S. borbonicum ou rares comme S. majus associé à différenciation marquée entre l'île Maurice et la Réunion au sein des deux lignées. De plus, il a été mis en évidence des patrons de structure de la diversité génétique différents selon l'île et l'espèce considérée : une structure spécifique dans le genre Sideroxylon de la section Calvaria à Maurice et une structure géographique chez S. cinereum de Maurice et les espèces réunionnaises. À l'échelle de la lignée des Sideroxylon de la section Calvaria, les marqueurs microsatellites nucléaires ont permis d'identifier clairement toutes les espèces avec une forte différenciation entre S. majus de la Réunion et l'ensemble des espèces mauriciennes. À Maurice, la différenciation est plus marquée entre S. grandiflorum et les deux autres espèces S. sessiliflorum et S. boutonianum avec des évènements d'hybridation entre ces deux dernières espèces possibles. À l'échelle de S. majus de la Réunion, une très forte diversité génétique structurée en trois groupes génétiques a été mise en évidence à l'aide de marqueurs microsatellites nucléaires. La comparaison de la diversité génétique des cohortes des adultes et des juvéniles ne présente pas d’érosion génétique. Des méthodes de conservation sont proposées en fonction de ces caractéristiques génétiques pour S. majus, espèce rare en danger. L'ensemble des résultats obtenus chez les Sapotacées endémiques des Mascareignes montre que la diversité génétique est structurée à différentes échelles spatiales, selon les espèces et les lignées évolutives considérées, soulignant la nécessité d'études complémentaires afin de déterminer les processus qui sont à l'origine des patrons détectés. / Madagascar is among the top five priorities "hotspots" for global biodiversity conservation. In Madagascar, melliferous flora is diverse and abundant; the endemic honey bee Apis melliferaunicolor inhabits all areas regardless of the climatic conditions and topography. As other islands, Madagascar is fragile and susceptible to invasions of alien species. In 2010, Varroa destructor has been reported parasitizing A. m. unicolor. The ectoparasite is not only a serious threat to beekeeping in Madagascar but it may also alter ecosystems balance.The objectives of this thesis were i) to study the genetic diversity and population structure of both A. m. unicolor and V. destructor in Madagascar, ii) to estimate the impact of V. destructor on honey bee colonies, and iii) to investigate the hygienic behaviour of honey beeOur results confirm that all honey bees collected in Madagascar belonged to the African evolutionary lineage and more than 99% were identified as A. m. unicolor. Despite its lownuclear genetic diversity, two genetic clusters have been detected, corresponding to geographic regions.In Madagascar, only one genetic strain of V. destructor was detected, the Korean haplotype (K1-1) which is the most widespread lineage in the world and the one present in Africa. Genetic studies showed a higher proportion of homozygous genotype (69.5%) and also a high number of MLG (Multi- Locus Genotypes) in the High Lands compared to the East coast. The presence of particular MLG on the High Land reinforces the assumption of its introduction into the capital. The spread of V. destructor in Madagascar is relatively slow in comparison with those observed in African countries. Its presence remains confined to the High Land and the East coast. The impact of the parasite on A. m. unicolor was severe; with about 60% of colony losses in a year reported in 2012. Nevertheless, this is less than observed in Europe, where many more colonies died at the early stage of infestation.Based on the percentage of cleaned cells observed 6 hour after pin killing the brood, the efficiency of A. m. unicolor colonies to detect and uncap cells was comparable to those of Africanised hygienic honey bees and was much higher than those of European honey bees. In Madagascar, the detection of highly hygienic colonies of A. m. unicolor is a great opportunity to develop a programme of selection of tolerant honey bee strains.
10

Poux humains : différenciation, distribution phylogéographique, host-switching et contrôle / Human lice : differenciation, phylogeographic distribution, host-switching and control

Drali, Rezak 15 December 2014 (has links)
Le pou de tête et le pou de corps sont deux écotypes indiscernables occupant chacun une niche écologique différente. Le pou de corps représente une menace réelle pour l'Homme en raison de son rôle de vecteur dans la transmission de trois maladies graves pour l'Homme à savoir: le typhus épidémique, la fièvre des tranchées et la fièvre récurrente. Dans cette thèse, nous avons obtenu des résultats concrets dans chacune des thématiques abordées. En effet, nous avons (i) mis en place un outil moléculaire qui permet de différencier pour la première fois entre le pou de tête et le pou de corps qui a montré efficacité sur le terrain, (ii) mis en évidence l'existence d'un nouveau clade mitochondrial (Clade D) renfermant des poux de tête et des poux de corps susceptible de vectoriser Bartonella quintana et Yersinia pestis, (iii) retracé les migrations humaines à travers l'analyse de poux anciens provenant de différentes périodes et localisations, (iv) démontré pour la première fois que Pediculus mjobergi est génétiquement proche du pou humain et confirmé l'hypothèse qu'à l'origine Pediculus mjobergi était un pou humain qui a été transféré aux singes du Nouveau Monde par les premiers Hommes à avoir atteint le continent américain il y a des milliers d'années et (v) mis en place un outil de détection et de contrôle de la résistance moléculaire des poux à la perméthrine. Cet outil fut particulièrement utile dans l'étude clinique que nous avons menée pour déterminer si l'utilisation de sous-vêtements imprégnés d'insecticide offrait une protection efficace à long terme contre les poux de corps infestant les personnes sans-abri. / Head louse (Pediculus humanus capitis) and body louse (Pediculus humanus humanus) are two indistinguishable ecotypes each occupying an ecological niche: hair for head louse and clothing for the body louse. Body louse represents a real threat to humans because of its role as vector for the transmission of three deleterious diseases namely epidemic typhus, trench fever and relapsing fever.In this thesis, we obtained concrete results that have led to scientific publications. Indeed, we (i) implemented a molecular tool to differentiate for the first time between head and body louse, (ii) we highlighted the existence of a fourth mitochondrial clade (Clade D) comprising head and body lice that can vectorize Bartonella quintana and Yersinia pestis, (iii) we traced human migration through the analysis of ancient lice from different periods and different area, (iv) we demonstrated for the first time that Pediculus mjobergi is genetically close to human louse and confirmed the hypothesis that initially Pediculus mjobergi was a human louse has been transferred to New World monkeys by the first humans who have reached the American continent thousands of years ago and (v) we have implemented a tool for detecting and monitoring the molecular resistance to permethrin of body lice that parasite sheltered homeless persons in Marseille. This tool was particularly useful in the clinical study we conducted to determine whether the use of long-lasting insecticide-treated underwear provides effective long-term protection against body lice in homeless persons.

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