978 resultados para Alcestis, Queen, consort of Admetus, King of Pherae
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Shaw-Shoemaker 22198.
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Includes an introductory poem by the Irish statesman and orator Walter Hussey Burgh.
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Mode of access: Internet.
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Recollections of the Empress Eugénie.--A fresh start and two portraits.--Two glimplses of Queen Victoria.--'Mount Music.'--An adventure in a train.--The quotation-fiend.--A winter of storm.--The opera fiasco.--An open secret.
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William Aldren Turner (1864-1945), in his day Physician to the National Hospital, Queen Square, and to King's College Hospital, London, was one of the major figures in the world of epileptology in the period between Hughlings Jackson in the latter part of the 19th century and the advent of electroencephalography in the 1930s. Although he also made contributions to knowledge in other areas of neurology, and with Grainger Stewart wrote a competent textbook on that subject, Turner's main professional interest throughout his career seems to have been epilepsy. On the basis of a series of earlier, rather heavily statistical, personal publications dealing with various aspects of the disorder, he authored what became a well-accepted monograph entitled Epilepsy-a study of the idiopathic disorder, which appeared in 1907, and he also gave the 1910 Morison lectures in Edinburgh on the topic. His writings on epilepsy over a period of three decades consolidated knowledge rather than led to significant advances, but helped maintain interest in the disorder during a rather long fallow phase in the development of the understanding of its nature. (C) 2005 Elsevier Ltd. All rights reserved.
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Hepatitis A virus (HAV), the prototype of genus Hepatovirus, has several unique biological characteristics that distinguish it from other members of the Picornaviridae family. Among these, the need for an intact eIF4G factor for the initiation of translation results in an inability to shut down host protein synthesis by a mechanism similar to that of other picornaviruses. Consequently, HAV must inefficiently compete for the cellular translational machinery and this may explain its poor growth in cell culture. In this context of virus/cell competition, HAV has strategically adopted a naturally highly deoptimized codon usage with respect to that of its cellular host. With the aim to optimize its codon usage the virus was adapted to propagate in cells with impaired protein synthesis, in order to make tRNA pools more available for the virus. A significant loss of fitness was the immediate response to the adaptation process that was, however, later on recovered and more associated to a re-deoptimization rather than to an optimization of the codon usage specifically in the capsid coding region. These results exclude translation selection and instead suggest fine-tuning translation kinetics selection as the underlying mechanism of the codon usage bias in this specific genome region. Additionally, the results provide clear evidence of the Red Queen dynamics of evolution since the virus has very much evolved to re-adapt its codon usage to the environmental cellular changing conditions in order to recover the original fitness.
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RÉSUMÉ GRAND PUBLIC La complexité des sociétés d'insectes (telles que les abeilles, les termites ou les fourmis) a depuis longtemps fasciné l'Homme. Depuis le débfit du XIXème siècle, de nombreux travaux observationnels, comportementaux et théoriques leur on été consacrés afin de mieux les décrire et comprendre. L'avènement de la biologie moléculaire à la fin du XXèrne siècle a offert de nouveaux outils scientifiques pour identifier et étudier les gènes et molécules impliqués dans le développement et le comportement des êtres vivants. Alors que la majorité de ces études s'est focalisée sur des organismes de laboratoire tel que la mouche ou les nématodes, l'utilisation de ces outils est restée marginale jusqu'à présent dans l'étude des sociétés d'insectes. Lors de ma thèse, j'ai développé des outils moléculaires permettant de déterminer le niveau d'activité de zo,ooo gènes chez la fourmi de feu, Solenopsis invicta, ainsi qu'une base de données et un portail en ligne regroupant les informations relatives à l'étude génétique des fourmis: Fourmidable. J'ai ensuite utilisé ces outils dans le cadre d'une étude comportementale chez la fourmis S. invicta. Dans les sociétés d'insectes, une hiérarchie peut déterminer le statut reproducteur des individus. Suite à la mort d'un dominant, les subordonnés entrent en compétition en vue d'améliorer leur statut. Un tel phénomène se produit au sein des colonies de S. invicta contenant une unique reine mère, des milliers d'ouvrières et des centaines de reines vierges ailées. A la mort de la reine mère, un grand nombre de reines vierges tentent de la remplacer en arrachant leurs ailes et en activant leurs organes reproducteurs plutôt que de partir en vol nuptial. Ces tentatives sont le plus souvent arrêtées par les ouvrières qui exécutent la plupart de ces reines sur la base de signaux olfactifs produits lors de l'activation des organes reproducteurs. Afin de mieux comprendre les mécanismes moléculaires impliqués, j'ai étudié l'activité de gènes au sein des reines au début de ce processus. J'ai ainsi déterminé que des gènes impliqués dans communication olfactive, le développement des organes reproducteurs et la métabolisation de l'hormone juvénile sont activês à ce moment là. La vitesse à laquelle les reines perdent leurs ailes ainsi que les niveaux d'expression de gènes sont ensuite liés à leur probabilité de survie. ABSTRACT : Honeybees, termites and ants occupy the "pinnacle of social evolution" with societies of a complexity that rivals our own. Humans have long been fascinated by social insects, but studying them has been mostly limited to observational and behavioral experiments. The advent of molecular biology first made it possible to investigate the molecular-genetic basis of development in model systems such as the fruit fly Drosophila melarcogaster or the roundworm Caenorhabditis elegans and subsequently their behavior. Molecular and genomic tools are now becoming available for the study of social insects as well. To permit genomic research on the fire ant, Solenopsis invicta, we developed a cDNA microarray that can simultaneously determine the expression levels of approximately 1oooo genes. These genes were assembled and bioinformatically annotated using custom pipelines. The obtained data formed the cornerstones for Fourmidable, a web portal centralizing sequence, gene annotation and gene expression data as well as laboratory protocols for research on ants. In many animals living in groups the reproductive status of individuals is determined by their social status. In species with social hierarchies, the death of dominant individuals typically upheaves the social hierarchy and provides an opportunity for subordinate individuals to improve their social status. Such a phenomenon occurs in the monogyne form of S. invicta, where colonies typically contain a single wingless reproductive queen, thousands of workers and hundreds of winged non-reproductive virgin queens. Upon the death of the mother queen, many virgin queens shed their wings and initiate reproductive development instead of departing on a mating flight. Workers progressively execute almost all of them over the following weeks. The workers base their collective decision on pheromonal cues associated with the onset of reproductive development of the virgin queens which occurs after orphaning. We used the aforementioned tools to determine that genes putatively involved in processes including olfactory signaling, reproductive development and Juvenile Hormone metabolism are differentially expressed at the onset of competition. Additionally, we found that queens that initiate reproductive development faster and, to a certain extent, shed their wings faster after orphaning are more likely to become replacement queens. These results provide candidate genes that are putatively linked to competition outcome. To determine the extent to which specific genes affect different aspects of life in ant colonies, functional tests such as gene activation and silencing will still be required. We conclude by discussing some of the challenges and opportunities for molecular-genetic research on ants. RÉSUMÉ Les sociétés d'abeilles, de termites et de fourmis sont d'une complexité proche de celle de la nôtre et ont depuis longtemps fasciné l'Homme. Cependant, leur étude était jusqu'à présent limitée aux observations et expériences comportementales. L'avènement de la biologie moléculaire a d'abord rendu possible l'étude moléculaire et génétique du développement d'organismes modèles tels que la mouche Drosophila melanogaster ou le nématode Caenorhabditis elegans, puis dans un second temps de leur comportement. De telles études deviennent désormais possibles pour les insectes sociaux. Nous avons développé une puce à ADN permettant de déterminer simultanément les niveaux d'expression de 1oooo gènes de la fourmi de feu, Solenopsís invicta. Ces gènes ont été séquencés puis assemblés et annotés à l'aide de pipelines que nous avons développés. En se basant sur les informations obtenues, nous avons créé un portail web, Fourmidable. Ce portail vise à centraliser toutes les informations de séquence, d'annotation et d'expression de gènes, ainsi que les protocoles de laboratoire utilisés pour la recherche sur les fourmis. Par la suite, nous avons utilisé les outils développés pour étudier un aspect particulier de S. invicta. Chez les animaux grégaires, une hiérarchie sociale peut déterminer le statut reproducteur des individus. Suite à la mort d'un individu dominant, les individus subordonnés peuvent entrer en compétition en vue d'améliorer leur statut. Un tel phénomène se produit au sein des colonies monogynes de S. invicta, qui contiennent habituellement une unique reine mère, des milliers d'ouvrières et des centaines de reines vierges ailées. Suite à la mort de la reine mère, dominante, un grand nombre de reines vierges, subordonnées, perdent leurs ailes et activent leurs organes reproducteurs au lieu de partir en vol nuptial. Au cours des semaines suivantes, les ouvrières exécutent la plupart de ces reines sur la base de signaux olfactifs produits lors de l'activation des organes reproducteurs. Afin de mieux comprendre les mécanismes moléculaires impliqués, nous avons étudié l'expression de gènes au début de cette compétition. Nous avons identifié 297 gènes différemment exprimés, dont l'annotation indique qu'ils seraient impliqués dans des processus biologiques dont la communication olfactive, le développement des organes reproducteurs et la métabolisation de l'hormone juvénile. Par la suite, nous avons déterminé que la vitesse à laquelle les reines perdent leurs ailes en début de compétition ainsi que les niveaux d'expression de gènes sont corrélés à la probabilité de survie des reines. Nous concluons en discutant des opportunités offertes par la recherche génétique sur les fourmis ainsi que les défis qu'elle devra surmonter.
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Hepatitis A virus (HAV), the prototype of genus Hepatovirus, has several unique biological characteristics that distinguish it from other members of the Picornaviridae family. Among these, the need for an intact eIF4G factor for the initiation of translation results in an inability to shut down host protein synthesis by a mechanism similar to that of other picornaviruses. Consequently, HAV must inefficiently compete for the cellular translational machinery and this may explain its poor growth in cell culture. In this context of virus/cell competition, HAV has strategically adopted a naturally highly deoptimized codon usage with respect to that of its cellular host. With the aim to optimize its codon usage the virus was adapted to propagate in cells with impaired protein synthesis, in order to make tRNA pools more available for the virus. A significant loss of fitness was the immediate response to the adaptation process that was, however, later on recovered and more associated to a re-deoptimization rather than to an optimization of the codon usage specifically in the capsid coding region. These results exclude translation selection and instead suggest fine-tuning translation kinetics selection as the underlying mechanism of the codon usage bias in this specific genome region. Additionally, the results provide clear evidence of the Red Queen dynamics of evolution since the virus has very much evolved to re-adapt its codon usage to the environmental cellular changing conditions in order to recover the original fitness.
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From the Tropic of Capricorn to Equator, the seasonality of domestic cat is known to be absent, i.e., these animals are considered non-seasonal breeders at these regions. We hypothesized that this particularity might have some influence on in vitro embryo production. The aim of this experiment was to determine the percentage of cleavage and morulae and blastocyst formation produced from oocytes recovered from queen ovaries of three distinct status - follicular, luteal or inactive - during two different reproductive seasons experienced by cats in southeast of Brazil (22°53'09" S and 48°26'42" W) - non breeding season (NBS), comprehending January to March; and breeding season (BS), August to October. Thirty queens were neutered. Ovaries were classified according to their status and were sliced in PBS for cumulus oocyte complex (COC) releasing. Grade I COC were washed three times in H-MEM supplemented with BSA, glutamine, sodium pyruvate, cysteine, streptomycin and penicillin. Oocytes were incubated in groups of 20-30 in 400µL of DMEM supplemented with FSH, LH, estradiol, IGF-I and basic fibroblast growth factor under mineral oil for 30 or 36 hours at 38°C in humidified environment of 5% de O2, 5% CO2 and 90% N2. COC were fertilized in Ham's F-10 medium supplemented with BSA, cysteine, pyruvate and streptomycin/penicillin (culture medium) with fresh semen selected through swim up technique. Eighteen hours later, the presumptive zygotes were denuded, the percentage of cleavage was determined and every 10 zygotes were transferred to 100mL drops of culture medium for culture during three days. After 72 hours of culture the percentage of morulae formation was evaluated and these structures were transferred to drops of the same culture medium. At the eighth day of culture blastocyst formation was analyzed. During NBS, from a total of 272 (inactive), 162 (luteal) and 134 (follicular) fertilized oocytes, the percentage of cleaved zygotes, morulae and blastocysts derived from inactive ovaries were 24.63, 16.54 and 8.09 respectively; for those derived from luteal ovaries, the percentage was 21.6, 12.96 and 8.64, and for those from follicular ovaries, they were 24.62, 16.41 and 8.21. Considering BS, from a total of 102 (inactive), 198 (luteal) and 86 (follicular) fertilized oocytes, the relative frequency (%) of cleaved zygotes, morulae and blastocysts derived from inactive ovaries were 64.7, 41.17 and 23.53 respectively; for those derived from luteal ovaries, the percentage was 64.14, 40.41 and 23.73, and for those from follicular ovaries, they were 63.95, 39.54 and 24.41. The results of this experiment demonstrate that no statistically significant difference (P<0.05) was verified in the frequency of cleaved embryos and morulae and blastocyst formation when comparing the three ovarian conditions in the same season. However the breeding season presented better results considering cleavage and morulae and blastocyst formation.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)