Vibrio anguillarum infects many fish species in aquaculture, reducing farm productivity and negatively impacting fish welfare. Deeper understanding of the biology of V. anguillarum, particularly during infections in vivo, will help to improve disease prevention and control. Thus, the aim of this thesis was to provide further insight into the infection biology of V. anguillarum with a view to identifying better ways to reduce the impact of this pathogen in aquaculture. Conventional studies on virulence, particularly those aiming to identify novel virulence factors, often employ transposon mutagenesis where the functions of individual genes in the bacterium are disrupted. These mutant libraries are screened to identify those with attenuated virulence, allowing subsequent identification of the gene responsible. Usually the native fish host would be used but such studies are increasingly difficult to perform due to regulations on vertebrate experiments and ethical concerns. As a result, alternative invertebrate hosts are now an important means to studying microbial infections, but few models have been assessed for bacterial pathogens of fish. In this thesis, larvae of the greater wax moth Galleria mellonella were evaluated as an alternative host to investigate V. anguillarum virulence. Wild-type V. anguillarum isolates killed larvae in a dose-dependent manner, replicated in the haemolymph, and larvae infected with a lethal dose of bacteria could be rescued by antibiotic therapy, thus indicating that V. anguillarum established an infection in G. mellonella. Crucially, virulence of 11 wild-type V. anguillarum isolates correlated significantly between larva and Atlantic salmon infection models, and studies with isogenic mutants knocked out for various virulence determinants revealed conserved roles for some in larva and fish infections, including the pJM1 virulence plasmid and rtxA toxin. Thereafter, 350 strains from a V. anguillarum random transposon insertion library were screened for attenuated virulence in G. mellonella. In total, 12 strains had reduced virulence and in these mutants the transposon had inserted into genes encoding several recognised and putative virulence factors, including a haemolytic toxin (vah1) and proteins involved in iron sequestration (angB/G and angN). Importantly, the transposon in one strain had inserted into an uncharacterised hypothetical protein. Preliminary investigations found this putative novel virulence factor to contain a GlyGly-CTERM sorting domain motif, with sequence similarity to VesB of Vibrio cholerae which is involved in post-translational processing of cholera toxin. Finally, three transposon insertion libraries were mass sequenced on a MiSeq platform to identify V. anguillarum genes lacking transposon insertions. These genes were assumed to be ‘required’ for viability in the conditions under which the mutants were selected, in this case tryptone soya agar. In total, 248 genes lacked a transposon insertion and were the putative ‘required’ genes, and these may be important chemotherapeutic targets for new approaches to combat V. anguillarum infections. This thesis has furthered our understanding of the biology of the important fish pathogen V. anguillarum using an ethically acceptable approach, and the findings may assist with new ways to reduce the burden of this bacterium in aquaculture.

Made available in DSpace on 2014-12-17T14:33:09Z (GMT). No. of bitstreams: 1 HonaraMS_DISSERT.pdf: 1764050 bytes, checksum: 8846e2477a7b0e0f242d2ada60121e07 (MD5) Previous issue date: 2013-03-26 / This study to aimed investigate the community of ectoparasites associated with birds in the Mata do Olho D ?gua, in the municipality of Maca?ba, Rio Grande do Norte (RN), Brazil, its structure and the ambiental and hosts influential variables on it, and to verify microhabitats preferences by species of chewing lice and feather mites. We examined 172 individuals belonging to 38 species of Passeriformes and non-Passeriformes. 12 new geographic records are reported and 11 host-parasite associations not yet known for chewing lice and feather mites species. Significant relationship was found between the abundance of chewing lice and the variables total length (r = 0.29, p <0.05) and exposed culmen (r = 0.38, p <0.05) of the hosts. A principal component (PC1) accounted for 90.1% of the hosts morphological variation was significantly influential on the abundance of chewing lice (p <0.05), indicating that the morphological characteristics of the hosts may be positively influencing the abundance of these ectoparasites. Significantly higher frequency of individuals with high loads of chewing lice was detected during the dry period (x ? = 8.5, p <0.05), corroborating studies that propose that birds of arid environments suffer as much pressure as those of parasitic humid environments. Analyses of null models of co-occurrence and niche overlap showed a high degree of structure in the feather mites and chewing lice assemblies, when compared with other groups, and preferences in the use of microhabitats by taxa identified. These results corroborate ecological theories in host-parasite systems, contribute to the knowledge of ectoparasites associated with neotropical birds, and the need for experimental studies, as well as further deepening the biology of these arthropods / O presente estudo teve como objetivos investigar a comunidade de ectoparasitos associada a aves Mata do Olho D ?gua, localizada no munic?pio de Maca?ba, Rio Grande do Norte, BR, sua estrutura e a influ?ncia de vari?veis ambientais e morfol?gicas dos hospedeiros, al?m de averiguar prefer?ncias de microh?bitat pelas esp?cies de ?caros de pena e mal?fagos em associadas ?s aves em estudo. Foram examinados 172 indiv?duos pertencentes a 38 esp?cies de aves Passeriformes e n?o-Passeriformes. S?o reportados 12 novos registros geogr?ficos para o Brasil e 11 associa??es ainda n?o conhecidas com hospedeiros de ?caros de pena e mal?fagos. Foi detectada rela??o significativa entre abund?ncia de mal?fagos e as vari?veis comprimento total (r= 0,29; p<0,05) e c?lmen exposto (r= 0,38; p<0,05) dos hospedeiros. Uma componente principal (CP1) respons?vel por 90,1% da varia??o morfol?gica dos hospedeiros foi significativamente influente sobre a abund?ncia de mal?fagos (p<0,05), indicando que caracter?sticas morfol?gicas dos hospedeiros podem estar influenciando positivamente a abund?ncia desses ectoparasitos. Frequ?ncia significativamente maior de indiv?duos com altas cargas de mal?fagos foi dectada durante o per?odo de seca (x?= 8,5; p<0,05), corroborando estudos que prop?em que aves de ambientes ?ridos sofrem tanta press?o parasit?ria quanto aquelas de ambientes ?midos. An?lises de modelos nulos de coocorr?ncia e sobreposi??o de nicho apontaram alto grau de estrutura nas assembleias de ?caros e mal?fagos, quando comparadas com outros grupos, e prefer?ncias no uso de microh?bitats pelos t?xons identificados. Estes resultados corroboram teorias ecol?gicas nos sistemas parasito-hospedeiro, contribuem para o conhecimento dos ectoparasitos associados ?s aves neotropicais e apontam a necessidade de estudos experimentais, assim como maior aprofundamento na biologia desses artr?podos

De nombreuses invasions par les mouches des fruits de la famille des Tephritidae sont observées dans le monde. C'est notamment le cas aux Comores, de par sa position géographique et de ses importations de produits frais depuis les pays voisins. Afin de déterminer les stratégies nécessaires permettant de diminuer les populations de plusieurs espèces de cette famille, il est indispensable de disposer d'un état des lieux sur l'écologie et la distribution des espèces présentes dans l'archipel. Les objectifs de cette thèse étaient : i) d'inventorier les espèces de Tephritidae présentes aux Comores et d'analyser les fluctuations saisonnières des populations en lien avec les facteurs climatiques et la phénologie des principales plantes-hôtes, ii) de déterminer la gamme de plantes-hôtes des principales espèces et iii) d'inventorier les parasitoïdes indigènes des Tephritidae et de suivre l'acclimatation du parasitoïde Fopius arisanus introduit à partir de 2013. Afin de mener à bien ces objectifs, un suivi hebdomadaire d'un réseau de piégeage ainsi que la phénologie des plantes présentes dans les îles Grande-Comore, Mohéli et Anjouan, a été réalisé durant une période deux ans. De même, des fruits cultivés et sauvages ont été échantillonnés dans différentes régions de la diversité écoclimatique de l'île de la Grande-Comore durant une période de trois ans. Cinq espèces de mouches de fruits ont été retrouvées dans l'ensemble de l'archipel à partir du réseau de piégeage : Bactrocera dorsalis, Ceratitis capitata, Dacus bivittatus, Dacuspunctatifrons et Dacus ciliatus. Une forte dominance de l'espèce envahissante B. dorsalis a été observée à toutes les saisons et dans tous les sites. La densité des espèces de Tephritidae était plus importante durant la saison chaude et humide que pendant la saison fraiche et sèche. De plus, les résultats ont montré une forte abondance de B. dorsalis dans les régions humides de basses altitudes alors que C. capitata, subsiste dans les régions sèches et d'altitude plus élevée. Les résultats suggèrent un phénomène de séparation de niches entre ces deux espèces liée au climat. Parmi 42 espèces de fruits échantillonnées apparentant à 22 familles de plantes, 22 fruits de 11 familles étaient infestés par des Tephritidae. Six espèces de mouches des fruits ont émergées des fruits échantillonnés avec une large dominance (91%) de B. dorsalis. Cette dernière espèce occupe une large gamme de plantes-hôtes (16 espèces), utilisant des fruits préalablement infestés par C. capitata. Quatre espèces de parasitoïdes de la famille des Braconidae, sous-famille d'Opiinae ont émergés des fruits dont l'espèce introduite F. arisanus. Cependant très peu d'individus ont été retrouvés pour le moment et il sera nécessaire de suivre l'acclimatation du parasitoïde, en termes de taux de parasitisme, de distribution et de gamme de fruit et d'espèces de Tephritidae hôtes. / Numerous invasions by fruit flies of the Tephritidae family are observed worldwide. This is particularly the case in Comoros, because of its geographical position and its imports of fresh products from neighboring countries. In order to determine the strategies necessary to reduce the populations of several species of this family, it is essential to have a current status on the ecology and distribution of the species present in the archipelago. The objectives of this thesis were to: (i) inventory the Tephritidae species present in Comoros and analyze the seasonal fluctuations of populations in relation to climatic factors and phenology of the main host plants, (ii) determine the host plants range of the main species and (iii) inventory the Tephritidae indigenous parasitoids and follow the acclimatization of theparasitoid Fopius arisanus introduced since 2013. In order to achieve these objectives, a weekly monitoring of a trapping network as well as plants phenology present in Grande-Comore, Mohéli and Anjouan islands was carried out during a period of two years. Similarly,cultivated and wild fruits were sampled in different regions of the ecoclimatic diversity of Grande-Comore island during a period of three years. Five fruit fly species were found throughout the archipelago from the trapping network: Bactrocera dorsalis, Ceratitis capitata, Dacus bivittatus, Dacus punctatifrons and Dacus ciliatus. High dominance of the invasive species B. dorsalis was observed at all seasons and at all sites. The density of Tephritidae species was greater during the hot and wet season than during the cool and dry season. In addition, the results showed a high abundance of B. dorsalis in humid regions of low altitudes while C. capitata, persists in dry regions of higher elevation. The results suggest a niche separation phenomenon between these two species related to climate. Among 42 fruit species sampled from 22 plant families, 22 fruits belonging to 11 families were infested with Tephritidae. Six fruit fly species have emerged with a large dominance (91%) of B. dorsalis. The latter species occupies a wide range of host plants (16 species), using fruits previously infested with C. capitata. Four parasitoids species of Braconidae subfamily Opiinae have emerged in fruits including introduced species F. arisanus. However, very few individuals have been found at this timeand it will be necessary to follow acclimatization of the parasitoid in terms of parasitism rates, distribution and host fruit and Tephritidae species range.

Plantas de mostarda-do-campo (Brassica rapa) exibindo intenso superbrotamento de ramos finos, com folhas e flores de tamanho reduzido, foram observadas em campos cultivados com couve-flor. Como os sintomas se mostravam similares àqueles induzidos por fitoplasmas, suspeitou-se que esta espécie daninha estava infectada por este tipo patógeno. Visando confirmar a diagnose, plantas foram amostradas e seu DNA extraído para ser usado em ensaios de duplo PCR, conduzidos com os iniciadores R16mF2/mR1, SN910601/SN011119, 16F2n/R2 e R16(III)F2/16(III)R. As amplificações de fragmentos genômicos correspondentes ao 16S rRNA revelaram uma constante associação entre um fitoplasma do grupo 16SrIII com as plantas sintomáticas. A doença foi denominada de superbrotamento. Cigarrinhas da espécie Agalia albidula foram coletadas nas áreas marginais e no interior dos campos de couve-flor, onde cresciam plantas de mostarda-do-campo. O DNA total foi extraído e usado em duplo PCR desenvolvido com os mesmos iniciadores citados anteriormente. Os resultados mostraram que os insetos analisados eram portadores de um fitoplasma do grupo 16SrIII. Para alguns isolados do fitoplasma encontrado em plantas de mostarda-do-campo, os produtos amplicados em duplo PCR com os iniciadores R16(III)F2/16(III)R foram sequenciados e confirmaram que as sequências pertenciam a um representante do grupo 16SrIII. Mapas de sítios putativos de restrição foram elaborados com o emprego de diversas endonucleases, porém não se logrou sucesso em definir a identidade deste fitoplasma ao nível de classificação de subgrupo. Com base nos resultados obtidos no presente estudo, plantas de mostarda-do-campo servem como hospedeiro alternativo de um fitoplasma do grupo 16SrIII, o qual foi anteriormente associado à doença conhecida como enfezamento, ocorrente em outras espécies de brássica, como repolho, brócolis e couve-flor. Assim, é sugerido que esta espécie daninha possa abrigar o agente de doença, garantindo sua sobrevivência e atuando como fonte de inóculo para as culturas comerciais. Além disto, cigarrinhas da espécie A. albidula podem ser apontadas como potenciais vetores do fitoplasma relacionado ao superbrotamento da mostarda-do-campo, bem como ao agente causal do enfezamento em brássicas. A presente pesquisa contribuiu para melhor compreensão dos aspectos relacionados aos enfezamentos das brássicas, envolvendo diversidade de fitoplasmas, gama de hospedeiros alternativos destes agentes de doença e ocorrência de vetores deste tipo de patógeno. / Mustard-field plants (Brassica rapa) showing intense shoots proliferation, small sized leaves and flowers, were observed in cauliflower production fields. Since the symptoms were similar to those induced by phytoplasmas, it was suspected that this weed was infected by this type of pathogen. To confirm the diagnosis, plants were sampled for DNA extraction to be used in nested PCR tests conducted with primers R16mF2/mR1, SN910601/SN011119, F6F2n/R2 and R16(III)F2/16(III)R. The amplification of genomic fragments corresponding to the 16S rRNA showed a constant association between a phytoplasma group 16SrIII with symptomatic plants. The disease was called witche\"s broom. Species of leafhopper, Agalia albidula, were collected in marginal areas and at cauliflower fields, where mustard-field plants grew. The total DNA was extracted and used in nested PCR carried out with the same primers mentioned above. The results showed that the insects analyzed were carriers of a phytoplasma group 16SrIII. For some isolates of phytoplasma found in mustard-field plants, the products obtained in nested PCR with primers R16(III)F2/16 (III)R were sequenced and confirmed that belonged to a representative 16SrIII group. Putative restriction sites maps, were prepared using a many restriction endonucleases, but no success has been achieved in defining the identity of the phytoplasma subgroup classification level. Based on the results in the present study, mustard-field plants could be an alternative host of a phytoplasma group 16SrIII, which was previously associated with the disease known as stunting, occurring in other species of rapeseed such as cabbage, broccoli and cauliflower. Thus, it is suggested this weed could harbor the disease agent, ensuring their survival and acting as a source of inoculum for commercial crops. Moreover, the species of leafhoppers, A. albidula, could be identified as a potential vector of the phytoplasma associated with witche\"s broom mustard-field as well as the causal agent of stunting in brassicas. This research contributed to understanding the issues related to stunting in brassicas, involving a diversity of phytoplasmas, range of alternative hosts of these disease agents and occurrence of vectors of this pathogen type.

Sabe-se que humanos, plantas e animais são colonizados por uma elevada diversidade de microrganismos e que esses organismos eucariotos dependem destes microrganismos para manutenção do seu desenvolvimento. Usando dois modelos de associação microrganismo-hospedeiro, foi testado a hipótese de que hospedeiros pertencentes a domínios da vida distintos, apesar de suas particularidades estruturais, genotípicas, filogenéticas e fisiológicas, compartilham similaridades nos modos de associação com a comunidade bacteriana. Sendo assim, o objetivo do presente trabalho foi mapear a comunidade bacteriana associada a plantas do gênero Anthurium endêmicas e/ou não. Paralelamente, mapear a comunidade bacteriana associada a gêneros distintos de cianobactérias, ao longo da curva de crescimento e quando esta é submetida a condições de cultivo distintas. Como resultados, primeiramente, foi observado que plantas Anthurium alcatrazense endêmicas da Ilha apresentam riqueza e diversidade menor que as plantas da espécie Anthurium loefgrenii coletada na ilha de Alcatrazes e também menor que as plantas Anthurium intermedium e Anthurium pentaphyllum coletadas na região de continente. Também foi observado que a estrutura da comunidade bacteriana associada as plantas de A. alcatrazense é distinta quando comparada com as plantas coletadas no continente e também da própria ilha de Alcatrazes. Essa dissimilaridade foi principalmente representada por OTUs afiliadas à Betaproteobacteria e Gammaproteobacteria. Esses resultados sugerem especificidade microrganismo-hospedeiro. Considerando a associação cianobactéria e bactérias heterotróficas, os resultados demonstraram que a comunidade bacteriana associada é especifica de acordo com o gênero de cianobactéria, composta principalmente por classes apresentando abundância relativa de sequencias distintas como, Betaproteobacteria, Gammaproteobacteria, Flavobacteria e Cytophagia. Por outro lado, foi possível observar que ao longo das fases de multiplicação da linhagem Microcystis aeruginosa, ocorre uma sucessão de grupos bacterianos, sendo principalmente representado pela variação da abundância de Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria e Flavobacteria relativo a fase estacionaria de multiplicação. Quando submetida em condições de cultivo distintas, foi possível observar que variações nas taxas de multiplicação da cianobactéria influenciaram uma modulação da estrutura da comunidade bacteriana associada, desta forma sugerindo que rápidas alterações na estrutura da comunidade bacteriana associada a M. aeruginosa, é resultado de processos de auto-regulação entre cianobactéria e bactérias heterotróficas associadas. De forma geral, pode-se sugerir que hospedeiros distintos apresentam padrões de associações com as bactérias similares, podendo estas similaridades sugerir estratégias para um melhor entendimento e manejo dos ecossistemas. / It is known that humans, plants and animals are colonized by a high diversity of microorganisms and that these eukaryotic organisms depend on these microorganisms to maintain their development. Using two microorganism-host association models, we hypothesized that hosts belonging to distinct domains of life, despite their structural, genotypic, phylogenetic and physiological particularities, share similarities in the modes of association with the bacterial community. Thus, the objective of this work was to map the bacterial community associated with plants of the genus Anthurium endemic and / or not. In parallel, map the bacterial community associated with distinct genera of cyanobacteria, along the growth curve of and when it is submitted to different culture conditions. In this context, we observed that Anthurium alcatrazense plants endemic to the Island, present less richness and diversity than the plants of the species Anthurium loefgrenii collected in the island of Alcatrazes and smaller than the plants Anthurium intermedium and Anthurium penthaphyllum collected in the continent. We found that the structure of the bacterial community associated with the plants of A. alcatrazense is distinct when compared to the plants collected in the continent and island of Alcatrazes itself. This dissimilarity was mainly represented by OTUs affiliated with Betaproteobacteria and Gammaproteobacteria. These results suggest microorganism-host specificity. Considering the association cyanobacteria and heterotrophic bacteria, the results demonstrated that the associated bacterial community is specific according to the genus of cyanobacteria, composed mainly by abundance distinct from those of classes, Betaproteobacteria, Gammaproteobacteria, Flavobacteria and Cytophagia. On the other hand, it was possible to observe that during the multiplication stages of the Microcystis aeruginosa strain, a succession of bacterial groups occurs, mainly represented by the variation of the abundance of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Flavobacteria relative to the stationary phase of multiplication. When submitted under different culture conditions, it was possible to observe that variations in cyanobacteria multiplication rates influenced a modulation of the associated bacterial community structure, thus suggesting that rapid changes in the bacterial community structure associated with M. aeruginosa is a result of processes of self-regulation between cyanobacteria and associated heterotrophic bacteria. In general, distinct hosts show patterns of associations with similar bacteria, and these similarities may suggest strategies for a better understanding and management of ecosystems.

Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is one of the major citrus pests of economic importance for South Africa’s citrus industry. It is endemic to Africa, and therefore a phytosanitary pest with zero tolerance by most export markets. The cryptic nature of T. leucotreta makes visual inspection an inefficient method for detecting neonate larvae in fruit in the packhouse. Therefore, a more accurate method for sorting infested fruit at the packhouse, particularly for newly infested fruit could ensure market access. A recent study showed that fruit infested by T. leucotreta emit a chemical profile different from that of a healthy fruit. Several studies provide evidence that parasitoids locate their hosts feeding on fruit by exploiting the novel chemical profiles produced due to host herbivory. The aim of this study was to evaluate the potential of using the naturally occurring behaviour of a larval parasitoid Agathis bishopi (Nixon) (Hymenoptera: Braconidae) for detection of T. leucotreta infested fruit, by determining which compound in infested fruit is attractive to parasitoids. Ytube olfactometer and flight-tunnel bioassays with healthy and T. leucotreta infested fruit showed a significantly stronger response of A. bishopi female parasitoids to infested fruit. Among the volatile compounds associated with T. leucotreta infested fruit, D-limonene elicited the strongest attraction to A. bishopi female parasitoids. Attraction of mated A. bishopi female parasitoids to T. leucotreta infested fruit and D-limonene significantly increased after oviposition experience. Behavioural responses of A. bishopi female parasitoids that were associated with T. leucotreta infested fruit were investigated to determine which behaviours are distinct and interpretable. Probing and oviposition behaviours were the most noticeable and were only elicited on infested fruit when parasitoids contacted T. leucotreta frass, indicating that chemical compounds in frass are short-range cues used for final host location. Since production of D-limonene by fruit is elevated due to herbivory by different pests including mechanical injury on fruit, response of A. bishopi female parasitoids to compounds in frass offers a more specific and potentially useful mechanism for development of a detection system for T. leucotreta infested fruit. Chemical analysis of T. leucotreta frass and conditioning A. bishopi parasitoids to respond behaviourally to compounds in frass is proposed.

La nanostructuration de surfaces par des réseaux supramoléculaires auto-assemblés de briques moléculaires a fait l'objet de nombreuses études au cours de ces dernières années, dans le but d’obtenir à terme des matériaux utilisables dans les nanotechnologies. Cependant, en plus du contrôle du positionnement des briques moléculaires sur la surface, le contrôle des propriétés de surface reste un enjeu important. Dans ce contexte, les réseaux nanoporeux sont intéressants car ils présentent des propriétés d'hôte et de sélectivité vis-à-vis de composés invités, de telles propriétés pouvant conduire à des surfaces fonctionnelles. Les travaux de cette thèse ont donc porté sur le développement de nouveaux réseaux nanoporeux organiques obtenus par auto-assemblage de tectons originaux sur un substrat de graphite afin de permettre la capture de nanoparticules magnétiques. Ce travail a donc consisté en la synthèse de briques moléculaires puis à l’étude de leur auto-assemblage par STM. Ces réseaux 2D ont ensuite permis de capturer des nanoparticules et d'obtenir leur organisation régulière à courte distance. Il a ainsi été démontré qu'en modifiant la morphologie des réseaux nanoporeux il est possible de moduler la distance entre les nanoparticules mais également leurs interactions avec le réseau auto-assemblé. Pour favoriser les interactions entre les nanoparticules et le réseau organique, une autre approche combinant non seulement le contrôle de l'organisation 2D mais également une fonctionnalisation hors du plan a été développée. Un nouveau réseau pseudo-3D composé de briques moléculaires, appelées tectons Janus, fonctionnalisées par des ligands, a ainsi été conçu et étudié par STM. / Surface nanostructuration by supramolecular self-assembly of organic building blocks is an area which is the subject of numerous studies for several years, in view of nanotechnology applications. However, besides the control of the building blocks organization on surface, the surface properties control still remains an important challenge. In this context, nanoporous networks are interesting because they exhibit host properties and selectivity toward guest compounds, such properties leading to functional surfaces. This thesis focus and deals with the development of new 2D or pseudo-3D nanoporous networks, obtained by the self-assembly of original organic building blocks on graphite HOPG (Highly Oriented Pyrolitic Graphite) substrate, to trap magnetic nanoparticles. Therefore, this work consisted in the synthesis of organic building blocks and the study of their self-assembly by STM. Afterwards, such 2D networks allowed the trapping of nanoparticles, leading to their regular organization on short distances. Thus, it was demonstrated that by modifying the morphology (lattice) of such nanoporous networks it is possible to modulate the distance between nanoparticles but also their interactions with the self-assembled network. To favor interactions between nanoparticles and the organic network, another approach combining not only the control of 2D organization but also an out of plane functionalization has been developed. Therefore, a new pseudo-3D network made up of building blocks, called Janus tectons, functionalized by alkyl-acid ligands, has been designed and studied by STM.

MSc (Applied Mathematics) / Department of Mathematics and Applied Mathematics / In this study, we develop a multiscale model of soil transmitted helminths in humans with a special reference to hookworm infection. Firstly, we develop a single scale model that comprises of five between host scale populations namely; susceptible humans, infected humans, eggs in the physical environment, noninfective worms in the physical environment and infective worms in the physical environment. Secondly, we extend the single scale model to incorporate within-host scales namely; infective larvae within-host, immature worms in small intestine, mature worm population and within-host egg population which resulted to a multiscale model. The models are analysed both numerically and analytically. The models are epidemiologically and mathematically well posed. Numerical simulation results show that there is a bidirectional relationship between the between-host and within-host scales. This is in agreement with the sensitivity analysis results, we noted that the same parameters that reduce reproductive number R0 are the same parameters that reduce the infective worms endemic equilibrium point. From the comparative effectiveness of hookworm interventions analysis results, we notice that any intervention combination that include wearing shoes controls and reduces the spread of the infection. The modelling framework developed in this study is vigorous to be applicable to other soil transmitted helminths infections / NRF

This article aims towards developing further understanding regarding the relation between the media phenomenon podcasts and source credibility amongst young adults in Sweden. Furthermore, the foundation for this essay is based on the previous and current empiricism regarding both podcasts and source credibility. This study has evaluated and discussed the function that podcasts contribute with in regards to bridging the gap between social media and journalistic publishing. To answer this study's aim of purpose, a qualitative and a quantitative research method have been applied. These research methods have consisted of a digital survey and a focus group survey. The purpose behind the research was to examine how young adults living in Sweden experience and reflect on the subject of podcasts in correlation with source credibility. The research was narrowed down to a specific set of three resource categories amongst podcasts. It was concluded from these studies’ research methods that similarities and differences were present in relation to already existing empiricism. Furthermore was the extubated data applied to the Parasocial Interaction Theory and Uses and Gratification Theory.  The extubated data showed how young adults consider themselves source critical in relation to information produced through podcasts. Furthermore it was revealed that young adults' source credibility is highly based on who the publisher and podcast host is and acts. After applying the two theories to the collected data it was illustrated that young adults’ source critical thinking was affected by their perceived personal relations towards the podcast hosts. It became apparent that podcasts within the public service sector were perceived more credible regardless of the podcast subject and podcast host. In further addition the collected data presented that credibility and source criticism amongst young adults is partly based on which genre of podcast that is consumed. This essay also conducts a discussion regarding how the relation between podcasts and source credibility can develop further in the future. / Följande arbete ämnar att bilda en ökad förståelse kring mediefenomet podcasts i relation till det samhällsaktuella begreppet källkritik. Således redovisas det hur tidigare forskning tillhörande forskningsområdena har bidragit till den nuvarande empirin inom ämnet. Uppsatsen beskriver och diskuterar podcasts som en medial kanal som verkar mellan sociala medier och journalistiskt publicerade verk. För uppsatsens syfte har en kvalitativ och en kvantitativ studie genomförts. Dessa forskningsmetoder utformades som en digital enkät och en fokusgruppsundersökning. Arbetet utgick från att undersöka hur unga vuxna i Sverige upplever och reflekterar kring podcasts i relation till källkritik inom tre olika podcastgenrer. Genom arbetets forskningsmetoder synliggjordes likheter och olikheter i relation till tidigare forskning och applicerades även i relation till två olika teorier. Dessa två teorier var Parasocial Interaction Theory och Uses and Gratification Theory. Studien visade att unga vuxna är generellt källkritiska till det material de får ta del av via podcasts, men att trovärdigheten och nivån av källkritik avgörs beroende på vem avsändaren och podvärden är. Genom applicering av de båda teorierna till studiens data från undersökningarna, synliggjordes det att lyssnarnas uppfattade personliga relationer till podcastvärdarna påverkade deras källkritiska tänkande. Ytterligare framgick det att podcasts med public service som avsändare ansågs vara mer trovärdiga oberoende ämnet och podcastvärd. Studien visade även att trovärdigheten och källkritiken hos unga vuxna är delvis beroende på vilken kategori av podcast som konsumeras. Uppsatsen för även en diskussion om hur källkritik kan appliceras i relation till mediefenomet podcasts i framtiden.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Roman Reddy R. Ganta / Ehrlichia and Anaplasma species are rickettsial organisms which infect a variety of mammalian species. The organisms are transmitted from ticks and are maintained in reservoir hosts. Several pathogens have been identified in recent years as the causative agents for emerging infections in people. One of the primary reservoir hosts for the pathogens is the white tailed deer. In this study, 147 deer blood samples and 37 ticks were evaluated for the prevalence of Ehrlichia/Anaplasma species by TaqMan-based real time amplification assay and DNA sequence analysis. One hundred and thirteen (74%) samples tested positive with the Ehrlichia/Anaplasma genera-specific probe. Further analysis of the samples with the probes specific for human ehrlichiosis agents, E. chaffeensis and E. ewingii identified 4 (2.7%) and 7 (4.7%) positives, respectively. Test positives from 24 randomly selected samples were further evaluated by sequence analysis targeting to a 450 bp segment of 16S rRNA gene. All 24 samples were confirmed as positive for the Ehrlichia GA isolate # 4 (GenBank #U27104.1). DNAs from 37 pools of ticks collected from the white tailed deer were also evaluated. The TaqMan-based real time PCR assay with Anaplasma/Ehrlichia common probe identified 29 (78%) tick pools as positives whereas E. chaffeensis- and E. ewingii-specific probes identified three (8%) and one (3%) positives, respectively. The PCR and sequence analysis of tick samples identified Gram-negative bacteria species which included one endosymbiont of Rickettsia species (one tick pool), one Alcaligenes faecalis strain (three tick pools), five different Pseudomonas species (9 tick pools) and five different uncultured bacteria organisms (7 tick pools). Although the pathogenic potential of the white-tailed deer isolates of Anaplasma and Ehrlichia agents remains to be established, their high prevalence and the presence of human ehrlichiosis pathogens in white-tailed deer is similar to earlier findings. The high prevalence of the deer isolates of Anaplasma and Ehrlichia species demonstrates the need for further assessment of the pathogenic potential of these organisms to people and domestic animals.