• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 419
  • 305
  • 125
  • 46
  • 41
  • 13
  • 12
  • 12
  • 8
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • Tagged with
  • 1158
  • 295
  • 163
  • 128
  • 110
  • 109
  • 106
  • 103
  • 101
  • 84
  • 81
  • 77
  • 71
  • 71
  • 58
  • 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.
341

Detailní taxonomická a klonální struktura druhového komplexu Daphnia longispina na podélném gradientu přehradní nádrže Želivka / Detailed taxonomic and clonal structure of the Daphnia longispina species complex on the longitudinal gradient of the Želivka Reservoir

Stodola, Jakub January 2013 (has links)
Canyon shaped reservoirs are characteristic by specific environmental horizontal gradients, so they enable existence of several species of the Daphnia longispina complex in one water body. Due to preference of distinct environmental conditions Daphnia species occurre in the different localities. The aim of my thesis was to analyze detail taxonomical and clonal structure of Daphnia longispina group by ten microsatellite markers on longitudinal gradient and compare it between two consecutive seasons. Simultaneously I received newly discovered divergent mitochondrial lineage from Želivka reservoir. It was confirmed, that the distribution of species and their hybrids in water reservoir was non-concidental and the taxonomic spatial distribution is in two consecutive seasons relatively constant. On the contrary the spatial and temporal distribution of clones was very heterogeneous. Clonal diversity in the interspecific hybrids was lower than in the coexisting parental species. This finding supports the hypothesis, that there exist reproductive barriers between parental genomes. Most of the clones were substantively variable, but several clones that occurred in both seasons in similar localities were found. It is possible that some clones are able of overwintering in hypolimnion and in the spring...
342

Påverkan till och från fiskodlingar med avseende på vattenkvalitén i svenska vattendrag : Fallstudie ”Slotts Lax AB”

Ekholm, Anton, Furunäs, Mattias January 2016 (has links)
Ett flertal vattendrag i Sverige är idag förorenade (till viss grad), däribland Dalälven. Östersjön är ett utsatt hav vad gäller näringstillförsel, där Dalälven är en bidragande del till detta. I takt med att kunskapsnivån stiger kring hur vattenkvalitén påverkar organismer och människor så kan specifika åtgärder tas fram för enskilda vattendrag, för att förbättra kvalitén. Rapporten handlar om fiskodlingar och hur dem påverkas av utsläpp från mänskliga aktiviteter, samt hur odlingen påverkar dess omgivande vattendrag. Fiskodlingar används främst för att odla fisk som livsmedel, men även fisk som är avsedd för utplantering till sjöar och hav. Utplantering av fisk görs främst för att minska trycket på den vilda fisken. Att bedriva en fiskodling innebär stort ansvar för verksamhetsutövaren, där lagar och krav som är fastställda av riksdagen måste uppfyllas. För att kontrollera lagar och krav har man regelbundna kontroller vid fiskodlingar från olika myndigheter. Större delen av dagens fiskodlingar ligger i kontakt med sjöar och hav, och kan därmed påverkas av yttre faktorer i form av mänkliga aktiviteter, men även från själva odlingen i sig. Påverkan som bygger på utsläpp från dessa kan både vara positivt och negativt för vattendraget beroende på hur förutsättningarna hos denna ser ut. Fiskodlingar kan även placeras på land, men är dock betydligt mer kostsamt i jämförelse med en odling placerad i vattendrag. Det finns vissa risker med att bedriva en fiskodling i vattendrag, med avseende på sjukdomar och rymning. Sjukdomar inom en fiskodling kan resultera i slakt, och denna kan även spridas till utomstående vattendrag. En rymning kan bidra till hybridisering och därav påverka det vilda beståndet av fisk, den kan även rubba näringsväven hos vattendraget i form av konkurrens med det vilda beståndet, men även via bioackumulation och biomagnifikation. Det finns vissa faktorer som avgör placeringen av en fiskodling, detta allt efter hur förutsättningarna ser ut och vilken fisk som odlas. Slotts Lax AB, som är en fiskodlingsverksamhet i Dalarna, har valt att odla sin fisk i vattendrag, detta främst för att minimera kostnaderna och nyttja den miljö som erbjuds, vid Dalälven och Siljan. Fisk kan även odlas på land, detta görs främst för  att minimera riskerna med rymning av fisk och spridning av sjukdomar. / Several rivers in Sweden, including Dalälven, are today contaminated  to certain degree. As the knowledge rises around how water quality affects the organisms and humans can specific measures be developed for water bodies, to improve the quality. This thesis focuses on fish farms and how they are affected by emissions from human activity, and how fish farming affects its surrounding water. Fish farms are mainly used to raise fish for human consumption, but also fish intended for planting out in lakes and seas. The planting of fish is mainly to reduce the pressure on wild fish. Conducting a fish farm involves great responsibility for the operator, where laws and requirements that are established by the parliament must be met. For that purpose the laws and requirements are regularly checked at farms from different agencies. Most of the fish farms are currently in contact with lakes and seas, and those can be affected by external factors such as human activities, but also from the culturing itself. Impact of emissions from fish farms can be both positive and negative for the watercourse, depending on the conditions of the area. Fish farms can also be placed on land, but this would be far more costly in comparison with fish farming in waterways. There are certain risks associated with conducting a fish in streams such as, diseases and fish escaping. Diseases in the fish farming can result in the slaughter, and this can also spread to outside watercourses. An escape can contribute to hybridization which therefore affect the wild population of fish, it can also disrupt the food chain of the stream in the form of competition with the wild population, but also through bioaccumulation and biomagnification. There are certain factors that determine the location of a fish farm, depending on how the conditions look likes and what kind of fish species that are being grown. Slotts Lax AB, which is a fish farming business in Dalarna, have chosen to grow their fish in streams, primarily in order to minimize costs and use the environment offered by the Dalälven River and Lake Siljan. Fish can also be grown on land, this is done primarily to minimize the risks of escape and the spread of diseases.
343

Poétique de l’exil dans les littératures allemande, française et arménienne : "Hypérion" de Friedrich Hölderlin, "Une saison en enfer" d’Arthur Rimbaud, "Le bois de Vincennes" de Nigoghos Sarafian / The Poetics of Exile in German, French, and Armenian Literature : Hölderlin, Rimbaud and Sarafian

Cermakian, Stéphane 18 December 2013 (has links)
Peut-on parler de « poétique » pour un phénomène aussi mouvant que l’exil ? Cette notion qui, dans ses diverses acceptions, ne se laisse pas fixer tout à fait, peut-elle faire apparaître un langage spécifique ? Il s’agira de voir par quels mécanismes cette éprouvante manifestation d’interculturalité peut mener à la création d’une langue qui dépasse le cadre de la nation (même en prenant sa source dans celle-ci), et rejoint des invariants et des structures d’expression transnationales et universelles. Pour ce faire nous prenons appui sur trois auteurs choisis dans des aires géographiques et des époques différentes : Hölderlin (aire germanique), Rimbaud (aire latine) et Sarafian (aire arménienne). L’exil se manifeste avant tout par rapport au pays d’origine, conformément à la définition. Mais il devient rapidement un phénomène linguistique, que ce soit dans le choc avec le monde étranger (Sarafian) ou dans la formulation d’une quête esthétique avec la création verbale pour enjeu (Rimbaud), liée pour une bonne part à la recherche d’une nouvelle mythologie et à la confrontation avec l’étranger pour retrouver ce qui appartient en propre à la nation (Hölderlin). Le pivot est ici la nation, originelle et actuelle, dont les poètes sont exilés. L’exil géographique et l’exil de la langue mènent finalement à l’exil spirituel et à la recherche d’une patrie plus élevée, tiers espace pouvant accueillir ou façonner une parole. Ce nouveau lieu serait celui d’une hybridation (ou du moins d’un questionnement) où le verbe de l’exil pourrait se dire, sous des formes différentes chez les trois auteurs, avec toutefois des similitudes frappantes. / Is it possible to speak about « poetics » with respect to a phenomenon which is as fluctuating as exile? May the latter, which, in its various meanings, cannot be totally defined, allow the emergence of a specific language? It is up to us to find out through which mechanisms such a trying expression of interculturalism might lead to the creation of a language which goes beyond the framework of the nation (even when it emanates from the latter) and which reaches out towards transnational and universal invariants and word structures. In order to achieve this, we rely upon three authors which were chosen in different geographic areas and in different periods : Hölderlin (Germanic area), Rimbaud (Latin area) and Sarafian (Armenian area). Exile is primarily defined with respect to the country of origin, in conformity with the definition. But it becomes a linguistic phenomenon, as in the shock with the foreign word after the genocide of the Armenians (Sarafian), or in the formulation of an aesthetic quest with verbal creation at stake (Rimbaud), or in the essential search of a new mythology, along with the confrontation with the foreign world in order to redefine that which belongs specifically to the nation (Hölderlin). Both the geographic exile and the linguistic exile lead to a spiritual exile and to the search for a loftier fatherland. This new spatial entity would result from a hybridization process (or at least from questioning), whereby the word of the exile could be expressed in different formats for the three authors, with, however, some striking similarities.
344

INCREASING RENEWABLE OIL CONTENT AND UTILITY

Serson, William Richard 01 January 2017 (has links)
Since the dawn of agriculture man has been genetically modifying crop plants to increase yield, quality and utility. In addition to selective breeding and hybridization we can utilize mutant populations and biotechnology to have greater control over crop plant modification than ever before. Increasing the production of plant oils such as soybean oil as a renewable resource for food and fuel is valuable. Successful breeding for higher oil levels in soybean, however, usually results in reduced protein, a second valuable seed component. We show that by manipulating a highly active acyl-CoA: diacylglycerol acyltransferase (DGAT) the hydrocarbon flux to oil in oilseeds can be increased without reducing the protein component. Compared to other plant DGATs, a DGAT from Vernonia galamensis (VgDGAT1A) produces much higher oil synthesis and accumulation activity in yeast, insect cells and soybean. Soybean lines expressing VgDGAT1A show a 4% increase in oil content without reductions in seed protein contents or yield per unit land area. Furthermore, we have screened a soybean fast neutrino population derived from M92-220 variety and found three high oil mutants that do not have reduced levels of protein. From the F2 plant populations we quantitatively pooled the high oil and low oil plants and performed comparative genomics hybridization (CGH). From the data it appears that two families have a 0.3 kb aberration in chromosome 14. We are performing further analysis to study this aberration and develop markers for molecular breeding. Mutagenic techniques are also useful for developing other traits such as early flowering varieties and adapting new high oil crops to a new region. Chia (Salvia hispanica) is an ancient crop that has experienced an agricultural resurgence in recent decades due to the high omega 3 fatty acid (ω-3) content of the seeds and good production potential. The area of cultivation has been expanded to Kentucky using mutagenized populations and the composition traits are similar to that of the original regions of cultivation in Central and South America.
345

A interação humano-computador por intermédio da tecnologia vestível / The human-computer interaction through wearable technology

Gonçalves, Andressa Caroline Sassarão 03 July 2019 (has links)
Tendo em vista a convergência entre a moda, a tecnologia e o universo Internet of Things (IoT), em português, Internet das Coisas, esta pesquisa procura considerar que o corpo e o vestuário podem ir além das aparências. Por meio de uma perspectiva abrangente, as questões que delineiam o contexto das wearables technologies foram levantadas. Aparatos estes que, por meio da união com a tecnologia ressignificaram a compreensão das funções das roupas e dos acessórios, e funcionam no corpo e para o corpo como extensões das capacidades limitantes atreladas a ele. Mediante a um cenário interdisciplinar, a pesquisa busca problematizar essas tecnologias pela visão da comunicação, do design, do consumo e também direcionar a indagações pertencentes à cultura do trans-humanismo. Engloba-se o contexto histórico e teórico da concepção dos primeiros vestíveis tecnológicos, as instâncias conceituais e comerciais, e os entraves, bem como possibilidades no âmbito de custo, funcionalidade e privacidade. Considera-se por meio desta pesquisa, o fomento quanto a uma recente área do saber, no qual a moda atua como um objeto de disseminação de padrões de consumo implicando diretamente na atuação do humano-computador o que permite que ele exista simultaneamente, estendendo os limites entre os espaços físicos na esfera virtual / In view of the convergence between fashion, technology and the Internet of Things (IoT), this research seeks to consider that body and clothing can go beyond appearances. From a comprehensive perspective, the issues that outline the context of wearables technologies have been raised. Devices that, through union with technology, have redefined the understanding of the functions of clothing and accessories, and function in the body and for the body as extensions of the limiting capacities attached to it. Through an interdisciplinary scenario, the research seeks to problematize these technologies through the vision of communication, design, consumption and also to direct inquiries pertaining to the culture of transhumanism. It encompasses the historical and theoretical context of the conception of the first technological garments, the conceptual and commercial instances, and the obstacles, as well as possibilities in the scope of cost, functionality and privacy. It is considered through this research, the promotion of a recent area of knowledge, in which fashion acts as an object of dissemination of patterns of consumption implying directly in the human-computer performance that allows it to exist simultaneously, extending the limits between physical spaces in the virtual sphere
346

Nouvelle approche de décryptage de la diversité bactérienne environnementale par capture magnétique de populations spécifiques de bactéries au sein de microbiotes complexes / Development of magnetic in situ hybridization technics for labelling and selective capture of bacteria for the study of environmental bacterial biodiversity.

Royet, David 16 March 2017 (has links)
Les bactéries, organismes les plus abondants de notre planète, ont un rôle fondamental dans le fonctionnement des écosystèmes. En dépit de leur importance, la caractérisation des communautés bactériennes (microbiotes) demeure encore aujourd’hui très incomplète. Ceci a pour origine l’impossibilité de complètement décrypter taxonomiquement et fonctionnellement les microbiotes de ces écosystèmes et donc à appréhender la diversité bactérienne dans son ensemble que ce soit par des approches culturales (avec seulement 1% de bactéries cultivables) ou par des approches metagénomiques limitées par les biais d’extraction, de séquençage et d’analyse. Les travaux entrepris dans le cadre de cette thèse visent à développer une nouvelle voie exploratoire passant par le fractionnement des microbiotes afin d’en étudier séparément les génomes des différentes populations ou groupes de populations, leur somme devant permettre de reconstituer un metagénome complet. Cet objectif requiert le développement d’un outil pour la sélection spécifique de bactéries (sur des critères taxonomiques ou fonctionnels) et leur isolement du reste des microorganismes non ciblés. Les travaux de thèse ont porté sur le développement d’une approche de marquage magnétique des bactéries basée sur l’hybridation moléculaire (hybridation in situ) complétée par celui d’un outil de tri microfluidique. Deux méthodes ont été développées, MISH et HCR, ciblant le gène de l’ARNr 23S, chacune reposant sur la formation, lors du processus d’hybridation, d’une structure secondaire en arborescence (MISH) ou ordonnée (HCR) permettant le greffage de nanoparticules magnétiques. Les résultats obtenus illustrent le potentiel des deux approches d’abord pour le marquage spécifique de bactéries cibles (E.coli et Pseudomonas putida) en conditions de culture au laboratoire puis dans un second temps dans des échantillons de sol. Le tri microfluidique a également été optimisé par le développement d’un nouveau dispositif de tri magnétique permettant la séparation des cellules marquées sous flux continu faisant appel à l’injection d’un polymère composite magnétique pour intégrer au fond du microcanal une série de bandes parallèles magnétiques. La fonctionnalité du dispositif a été démontrée, sa simplicité de fabrication en faisant un outil de choix pour une application en routine dans les laboratoires d’écologie microbienne. En dépit de résultats prometteurs toute cette nouvelle approche d’étude de la diversité bactérienne environnementale nécessite encore de nombreuses étapes d’optimisation. / Bacteria, the most abundant organisms on our planet, have a fundamental role in ecosystem functioning. Despite their importance, the characterization of bacterial communities is today still incomplete. This is due to the impossibility of completely decomposing taxonomically and functionally the microbial communities of these ecosystems and as a consequence to apprehend the whole bacterial diversity, either by cultural approaches (with only 1% of culturable bacteria) or by metagenomic, a limited approaches cause by biases in extraction, sequencing and analysis. The work undertaken in this thesis aims to develop a new exploratory pathway through the fractionation of microbiota in order to study separately genomes of different populations or groups of populations. Their sum should enable reconstitution of complete metagenome. This objective requires the development of a tool for the specific selection of bacteria (on taxonomic or functional criteria) and their isolation from the rest of the non-target microorganisms. The thesis work focused on the development of a magnetic labeling approach for bacteria based on molecular hybridization (in situ hybridization) complete by development of a microfluidic cell-sorting tool. Two methods have been developed, MISH and HCR, targeting the 23S rRNA gene, each based on the formation, during the hybridization process, of a secondary random structure (MISH) or organized structure (HCR) enabling binding to magnetic nanoparticles. Results obtained illustrate the potential of the two approaches initially for the specific labeling of target bacteria (E.coli and Pseudomonas putida) under laboratory conditions and then in soil samples. The microfluidic sorting was also optimized by the development of a novel magnetic cell-sorting device allowing the separation of the labeled cells under continuous flow using the injection of a magnetic composite polymer to integrate a series of magnetic parallel strips at the bottom of the microchannel. The proper functioning of the sorting device has been demonstrated, its simple production making it a tool of choice for a routine application in laboratories of microbial ecology. Despite promising results all this new approach for studying environmental bacterial diversity is still requiring many optimization steps.
347

Hibridação Genômica Comparativa em Endometriose / Comparative Genomic Hybridization in Endometriosis

Castelli, Luciana Caricati Veiga 31 March 2008 (has links)
A endometriose é uma doença ginecológica benigna comum, mas agressiva, caracterizada pela presença de tecido endometrial ectópico. A teoria mais aceita para explicá-la é a teoria de Sampson, na qual o tecido endometrial descamado durante a menstruação sofre refluxo através das tubas uterinas, adere e se prolifera em sítios ectópicos da cavidade peritoneal. Por outro lado, apenas o refluxo tubário não é capaz de estabelecer a doença e vários estudos sugerem uma etiologia multidimensional incluindo fatores hereditários, hormonais e imunológicos. Várias metodologias têm sido propostas com o objetivo de identificar genes candidatos para a endometriose. A hibridação genômica comparativa (CGH) é uma técnica que permite que o genoma inteiro seja analisado em um só experimento, sem a necessidade de cromossomos metafásicos obtidos por cultura celular. Nossa proposta foi avaliar, por CGH, amostras de endometriomas ovarianos e de tecido endometrial eutópico de dez pacientes com diagnóstico firmado de endometriose, para screening do genoma. No grupo eutópico, 6/10 amostras apresentaram alterações caracterizadas por perdas ou ganhos de regiões cromossômicas e no grupo ectópico foram encontradas alterações em 7/10 casos. A presença de perdas e ganhos de regiões cromossômicas no endométrio eutópico, histologicamente normal, de mulheres com endometriose ovariana, pode ser considerada como alteração primária ao desenvolvimento da doença. A metodologia de CGH permitiu a detecção das regiões cromossômicas 11q12.3-q13.1, 17p11.1-p12 e 17q25.3-qter como regiões críticas, direcionando investigações futuras para identificação de genes associados à endometriose. / Endometriosis is a common benign gynecological disease, very aggressive, characterized by the presence of ectopic endometrial tissue. The most accepted theory to explain it is Sampson\'s implantation theory, which says that the endometrial tissue exfoliated during menstruation undergoes reflux through the uterine tubes, adheres and proliferates in ectopic sites of the peritoneal cavity. On the other hand, only reflux is not enough to the establishment of the disease and a number of studies suggest a multidimensional etiology including hereditary, hormonal and immunological factors. Several methodologies have been proposed for the identification of candidate genes for endometriosis. The comparative genomic hybridization (CGH) is a versatile technique that allows the entire genome to be analyzed in only one experiment without the necessity of metaphasic chromosomes from the sample, excluding the cell culture. We aimed to evaluate, by CGH, ovarian endometriomas and eutopic endometrial tissue samples from 10 patients with confirmed diagnosis of endometriosis, for a genomic screening. In the eutopic group, 6/10 samples presented genomic imbalances and 7/10 cases showed alterations in the ectopic group. The presence of losses and gains of chromosomic regions in the histologically normal eutopic endometrium from women with ovarian endometriosis can be considered as a primary alteration in the development of the disease. The CGH methodology allowed the detection of chromosomic regions 11q12.3-q13.1, 17p11.1-p12 and 17q25.3-qter as critical regions, leading to future investigations for the identification of genes associated to endometriosis.
348

Interações de isolados clínicos de Prevotella intermedia e Prevotella nigrescens com Porphyromonas gingivalis na formação de biofilmes. / Interactions of clinical isolates of Prevotella intermedia and Prevotella nigrescens with Porphyromonas gingivalis in biofilm formation.

Barbosa, Graziela Murta 29 November 2013 (has links)
Prevotella intermedia e Prevotella nigrescens são espécies comumente associadas Porphyromonas gingivalis. os objetivos foram verificar a co-agregação entre cepas de P. intermedia, P. nigrescens e P. gingivalis; quantificar a biomassa, avaliar a proporção dos microrganismos nos biofilmes mistos; verificar a interferência do co-cultivo pela técnica de dois compartimentos, avaliar os biofilmes em ensaios de Hibridização In Situ (FISH) e verificar o papel dos genes PINA0102 e PIN0398 de P. intermedia no biofilme. Assim, 9 isolados clínicos de P. intermedia e 5 de P. nigrescens, as cepas padrão P. intermedia 17, P. intermedia 25611, P. nigrescens 33563, P. gingivalis W83, P. gingivalis 33277, os mutantes Pi17D0398 e Pi17D0102 foram avaliados em variados consórcios. Os resultados mostraram que as interações investigadas são cepa específicas. / Prevotella intermedia and Prevotella nigrescens are commonly associated with periodontal diseases. The goals of this study were to determine the co-aggregation of strains of P. intermedia, P. nigrescens and P. gingivalis; to quantify the biomass of these associations, to evaluate the ratio of these microorganisms in heterotypic biofilms, to verify the modulation of biofilms in co-culture using a trans-well system; to evaluate the structure of the biofilms by Fluorescent Hybridization In Situ (FISH) and to determine the role of genes PINA0102 and PIN0398 of P. intermedia in the modulation of its biofilm. Therefore, 9 clinical isolates of P. intermedia, 5 of P. nigrescens, type strains P. intermedia 17, P. intermedia 25611, P. nigrescens 33563, P. gingivalis W83, P. gingivalis 33277 and mutant strains Pi17D0398 and Pi17D0102 were grown in consortia of two strains. Our data demonstrate that the associations of P. intermedia, P. nigrescens and P. gingivalis are strain-specific.
349

Circuitaria e assinatura neuroquímica das projeções entre a habenula lateral, o núcleo tegmental rostromedial e o núcleo dorsal da rafe. / Circuitry and neurochemical signature of projections between the lateral habenula, the rostromedial tegmental nucleus and the dorsal raphe nucleus.

Sego, Chemutai 27 June 2013 (has links)
A habenula lateral (LHb) inibe neurônios dopaminérgicos no mesencéfalo através de um nodo GABAérgico no tegmento mesopontino, o núcleo tegmental rostromedial (RMTg). Ambos a LHb e o RMTg também projetam para o núcleo dorsal da rafe (DR). A organização das projeções da LHb e do RMTg para o DR foi investigada através de injeções de um traçador anterógrado na LHb ou no RMTg e confirmada com injeções de traçadores retrógrados. Para identificar o fenótipo neuroquímico das projeções RMTg-DR, combinamos a hibridização in situ para mRNA de GAD67 com a detecção imunoistoquímica de traçadores retrógrados injetados no DR. Caracterizamos as subdivisões-alvo das projeções RMTg-DR através de dupla-imunofluorescência para o traçador anterógrado injetado no RMTg e serotonina ou o transportador vesicular de glutamato do tipo 3. Detectamos uma projeção focal direta da divisão medial da LHb para a parte caudal do DR. Em contraste, projeções GABAérgicas robustas do RMTg foram direcionadas para uma subdivisão central do DR enriquecida em neurônios presumidamente glutamatérgicos. / The lateral habenula (LHb) inhibits mesencephalic dopamine neurons through a mesopontine GABAergic node, the rostromedial tegmental nucleus (RMTg). Both LHb and RMTg also project to the dorsal raphe nucleus (DR). The organization of LHb and RMTg projections to the DR was investigated using anterograde tracer injections into the LHb or RMTg and confirmed with retrograde tracer injections. To identify the neurochemical phenotype of RMTg-DR projections, we associated in situ hybridization for GAD67 mRNA with immunohistochemical detection of retrograde tracers deposited in the DR. DR target regions of RMTg projections were characterized using double-imunofluorescence techniques for the anterograde tracer deposited into the RMTg and either serotonin or the type 3 vesicular glutamate transporter. We detected a focal direct projection from the medial LHb division to the caudal DR. In contrast the RMTg emits robust GABAergic projections to a central DR subdivision rich in presumptive glutamatergic neurons.
350

Mudanças genéticas e fenotípicas associadas à criação de Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae) nos hospedeiros natural e alternativo e os efeitos da hibridização intraespecífica no seu fitness / Genetic and phenotypic changes associated with Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae) rearing on natural and alternative hosts and the effects of intraspecific hybridization in its fitness

Bertin, Aline 24 February 2016 (has links)
A criação de inimigos naturais em laboratório pode resultar em mudanças genéticas e fenotípicas drásticas devido às alterações ocasionadas principalmente pela deriva genética, endogamia e seleção natural. Estas alterações podem afetar o fitness das populações e reduzir a capacidade adaptativa às condições naturais. Além disto, a criação de inimigos naturais em hospedeiros alternativos pode comprometer a eficiência em campo. Poucos estudos tiveram como objetivo estudar estratégias para minimizar estes efeitos em condições de laboratório. Quantificar a variação genética em características biológicas pode auxiliar a estimar a resposta adaptativa às condições de criação, além de fornecer informações importantes para o melhoramento de agentes de controle biológico. A hibridização intraespecífica, ou seja, o cruzamento entre populações divergentes também pode ser um método relevante e eficaz para aumentar a aptidão biológica de agentes de controle, uma vez que permite a introdução de variação genética externa capaz de recuperar o fitness de populações mantidas em laboratório por muito tempo. Desta forma, este trabalho teve como objetivo estudar as mudanças genéticas e fenotípicas associadas à criação de Trichogramma galloi nos hospedeiros natural e alternativo, bem como investigar a herdabilidade de caracteres fundamentais para o desempenho do parasitoide e identificar os efeitos da hibridização intraespecífica em populações já estabelecidas em laboratório. Os resultados mostraram que a longevidade, a porcentagem de emergência e o número de parasitoides por ovo do hospedeiro apresentaram um aumento entre gerações para a população mantida no hospedeiro natural, indicando haver sinais de adaptação às condições de criação. No entanto, para a população mantida no hospedeiro alternativo foi observada uma redução na fecundidade e porcentagem de emergência quando oferecido o hospedeiro natural para o parasitismo, indicando haver um custo adaptativo associado à utilização de um novo hospedeiro. Foi possível verificar a existência de variação genética significativa na fecundidade. Em média, 46% da variância fenotípica observada foi determinada pela variância genética aditiva, sendo os demais 54% devido à variância ambiental e componentes genéticos dominantes. Nos cruzamentos intraespecíficos não foram observados casos de heterose, no entanto, foi observada a recuperação do fitness em híbridos obtidos a partir da população que apresentava desempenho inferior. Como conclusões deste trabalho, (i) foi possível detectar sinais de adaptação às condições de laboratório na população mantida no hospedeiro natural e uma menor eficiência sobre a praga alvo ao longo das gerações na população mantida no hospedeiro alternativo; (ii) verificou-se variação genética significativa na fecundidade da população estudada e; (iii) a hibridização intraespecífica se mostrou eficaz para amenizar os efeitos da depressão por endogamia em uma das populações de T. galloi estudada. / The rearing of natural enemies in laboratory conditions can result in drastic genetic and phenotypic changes due to natural selection, inbreeding, and genetic drift. These changes may affect population fitness and reduce the adaptive potential in natural conditions. Moreover, rearing on alternative hosts may compromise field efficiency. Few studies have focused in strategies to minimize these effects in laboratory conditions. Quantify the genetic variation in biological traits can help estimate the adaptive response to rearing conditions in addition to provide important information for the improvement of biological control agents. Intraspecific hybridization, that is, the crossing between different populations may also be an important and effective method to increase fitness, since it introduces genetic variation able to recover the fitness of populations under laboratory for a long time. Thus, the aims of this work were to: study the genetic and phenotypic changes in laboratory populations of Trichogramma galloi on the natural and alternative host, investigate the heritability of fundamental traits to parasitoid success and identify the effects of intraspecific hybridization in populations already established in the laboratory. The results showed that longevity, emergence rate and the number of parasitoids per host egg increased between generations for the population maintained on the natural host, which corresponds to adaptation signs to the rearing conditions. However, the population reared on the alternative host had a reduction in fecundity and emergence rate when exposed to the natural host, indicating that there is a fitness cost associated with the utilization of a new host. It was possible to verify the existence of significant genetic variance in fecundity. On average, 46% of the observed phenotypic variance was determined by the additive genetic variance, with the remaining 54% due to environmental variance and dominant genetic components. In the intraspecific crosses there were no cases of heterosis, however, the recovery of fitness was observed in hybrids obtained from the population with lower performance. In summary, (i) it was possible to detect signs of adaptation to the rearing conditions in the population maintained on the natural host and a reduction in the efficiency on the target pest over the generations in the population reared on the alternative host; (ii) there was significant genetic variation in fecundity of the population studied and (iii) intraspecific hybridization proved to be effective to mitigate the effects of inbreeding depression in one of the populations of T. galloi studied.

Page generated in 0.019 seconds