A atividade de neurônios em rajadas de disparo (bursts) é onipresente em sistemas nervosos. No entanto, o papel funcional dos bursts na codificação de informação ainda não é completamente compreendido. A dinâmica de burst tem sido intensivamente estudada em centros geradores de padrões (CPGs) que são exemplos clássicos de sistema nervoso autônomo em que a atividade em bursts está diretamente associada ao controle motor. Estudos recentes investigaram pequenas perturbações na dinâmica aparentemente periódica de neurônios com atividade em burst (bursters): padrões sutis nos tempos de disparo (spikes) dentro de um mesmo burst. Padrões de spikes intraburst (PSIBs) são tradicionalmente negligenciados por falta de relação com a função motora do CPG, no entanto, esses estudos mostraram que PSIBs são específicos para cada tipo de célula do CPG estomatogástrico de crustáceos e além disso, são capazes de refletir mudanças na conectividade da rede, indicando um possível papel na codificação de informação. Nesse trabalho, abordamos esse assunto investigando como um neurônio motor com atividade em bursts expressa informação a respeito de outros neurônios da rede através dos PSIBs. Realizamos experimentos registrando a atividade de neurônios pilóricos do gânglio estomatogástrico tanto na rede intacta como em uma rede híbrida na qual um neurônio pilórico interage em tempo real com um neurônio modelo através de uma sinapse artificial. Para inferir a sensibilidade dos PSIBs pós sinápticos aos pré-sinápticos desenvolvemos uma ferramenta de análise baseada em Teoria da Informação para encontrar padrões de máxima informação (ou seja, encontrar o bin que produz PSIBs de máxima entropia) e calcular informação mútua média entre eles (IMM) ao longo do burst de cada neurônio. Esta ferramenta também é potencialmente útil à análise de outros tipos de processos puntuais por fornecer um método de revelar informação oculta em padrões de eventos. Encontramos que um único neurônio motor é capaz de expressar no início de seu burst informação contida nos PSIBs do início do burst anterior do neurônio pré-sináptico. Esse fenômeno é observado em diferentes espécimes e espécies, o que sugere um mecanismo geral de codificação de informação. Além disso, esse efeito foi reproduzido em experimentos com uma rede híbrida, onde os estímulos pré-sinápticos são totalmente controlados, livre de qualquer influência de outros elementos no circuito. Esses resultados sugerem que a microestrutura dos padrões de disparo pré-sinápticos são codificadas se dá através de uma única sinapse, de maneira não linear e não homogênea nos PSIBs pós sinápticos. Dessa forma, neurônios motores são capazes de usar escalas de tempo diferentes para expressar dois tipos de informação: o ritmo de burst (associado à taxa de disparo) carrega informação sobre a contratação motora, enquanto que em uma escala de tempo muito menor, os PSIBs (associados à codificação temporal) expressam informação sobre o comportamento de outros neurônios do CPG. Além disso, encontramos que a informação dos PSIBs de um neurônio pilórico é codificada na estrutura temporal de disparo das unidades ativas registradas em um nervo do sistema estomatogástrico que projeta em áreas sensoriais do cérebro do animal. Assim, o mecanismo de codificação descrito pode ser parte de uma via de transmissão de informação previamente desconhecida, sugerindo que a codificação de informação através dos PSIBs poderia ser aproveitada para a regulação dos padrões de disparo em circuitos remotos pelo sistema nervoso central. / Burst firing is ubiquitous in nervous systems. However, the functional role of burst firing in information coding is mostly unknown. Bursting dynamics have been intensively studied in Central Pattern Generators (CPGs), classical examples of autonomous nervous circuits in which the most conspicuous bursting activity is clearly associated to motor function. Recent studies have investigated small perturbations embedded in the otherwise seemingly periodic bursting: the subtle intra-burst spike timing patterns (IBSPs), traditionally neglected for their lack of relation to the CPG motor function. Moreover, IBSPs were found to be cell-type specific and able to reflect changes in CPG connectivity, indicating a potential role in information coding. Here we addressed this matter by investigating how a bursting motor neuron expresses information about other neurons in the network. We performed experiments on the crustacean stomatogastric pyloric CPG, both in control conditions and when interacting in real-time with computer model neurons. The sensitivity of post- to pre-synaptic IBSPs was inferred by computing their average mutual information along each neuron burst. We found that a single motor neuron is able to express, at the beginning of its burst, information about the IBSPs of the beginning of the pre synaptic neuron\'s burst. This phenomenon is observed in different specimens and species, sugesting a genera information coding mechanism. Moreover, this effect was reproduced in a hybrid circuit, in which the presynaptic stimuli are completely controled by the experimenter free of any influence of other elements in the circuit. These results suggest that the presynaptic spiking microstructure are non-linearly and in homogeneously encoded through a single synapse in the post synaptic IBSPs. This way, motor neurons are able to use different time scales to express two types of information simultaneously: muscle contraction (related to bursting rate), and the behavior of other CPG neurons (in a much smaller timescale by using IBSPs as information carriers). Therefore, the coding mechanism described takes part in a previously unsuspected information pathway, providing evidence of the general physiological role of information coding through IBSPs in the regulation of neuronal _ring patterns in remote circuits by the central nervous system.

A alergia alimentar tem se tornado um problema crescente de saúde pública em muitos países e pode ser desencadeada por qualquer alimento. Em crianças os alimentos considerados mais alergênicos são leite de vaca e ovo e em adultos há uma alta frequência de alergia a frutos do mar, sendo camarão o marisco considerado mais alergênico. Clinicamente a alergia a camarão pode se manifestar em diferentes formas como dermatite atópica, angioedema ou até mesmo anafilaxia. Com base na história clínica e avaliação de resultados de exames complementares foram selecionados 18 indivíduos alérgicos a camarão e 9 não alérgicos como grupo controle. Foram realizados testes in vitro para dosagem de IgE especifica no soro e teste cutâneo. Para reações ocorridas há mais de um ano foi realizada provocação oral para confirmação diagnóstica. O soro de todos os indivíduos do estudo foram testados em Western Blotting 1D e 2D com extrato de carne de camarão e casca separadamente da espécie Xiphopenaeus kroyeri, que possui grande importância por ser altamente consumida em nosso país além de estar entre as dez estirpes mais capturadas no mundo. Ainda assim não está presente em nenhum teste comercial disponível e não há nenhum alérgeno descrito para o mesmo. A caracterização de suas moléculas alergênicas é importante para melhor auxilio no diagnóstico e tratamento de pacientes alérgicos. As proteínas que apresentaram reatividade IgE especifica foram submetidas a espectrometria de massas para identificação. Foi possível identificar alguns homólogos de alérgenos de outras espécies de camarão como, tropomiosina, arginina quinase, proteína sarcoplasmática de ligação ao cálcio, actina, cadeia leve e pesada de miosina e hemocianina. Encontramos um possível novo alérgeno denominado como citocromo c oxidase (subunidade I) que não foi descrito anteriormente como proteína alergênica. Analisando sensibilidade e valor preditivo positivo das nossas proteínas sugerimos que algumas delas podem ser boas candidatas como futuros marcadores diagnósticos para alergia a camarão. Quando comparamos o perfil de proteínas reativas em carne e casca de camarão não observamos diferenças significativas entre elas. Essa é a primeira descrição de alergia para a espécie de camarão X. kroyeri, popularmente conhecido como camarão sete barbas, mostrando reatividade a IgE especifica em pacientes alérgicos a camarão / Food allergy has become a growing problem of public health in many countries, and can be triggered by any food. In children the most allergenic foods are cow\'s milk and egg; in adults there are high frequencies of allergy to seafood, and shrimps are considered the most allergenic seafood. Clinically, shrimp allergy can manifest itself in different forms, such as atopic dermatitis, angioedema or even anaphylaxis. Based on the clinical history and evaluation of the tests, we selected eighteen subjects that were allergic to shrimp, and nine non-allergic to shrimp as a control group. In vitro tests were performed to IgE specific dosage and cutaneous test with commercial extract. When reactions occurred more than one year before oral provocation test was performed for diagnostic confirmation. The serum of all individuals were tested in Western Blotting 1D and 2D with the shrimp meat and shell extracts separately from the species Xiphopenaeus kroyeri, which has great importance since is highly consumed in the Southeast region of our country and is among the top ten captured species in the world. Nevertheless, there are no commercial clinical tests available for it, and there is no specific allergen described, both of them would help the diagnosis and treatment of allergic patients. Proteins that showed specific IgE reactivity were submitted to mass spectrometry for identification. We identified some homologues allergens from other shrimp species such as tropomyosin, arginine kinase, calcium-binding sarcoplasmic protein, actin, myosin heavy chain and hemocyanin. We founded a possible new allergen called cytochrome c oxidase (subunit I), that was never previously described as an allergenic protein. Analyzing sensitivity and positive predictive value of our proteins we suggest that some of them may be good candidates as future diagnostic markers for shrimp allergy. When comparing the reactive proteins profile in shrimp meat and shell, we did not observe significant differences between them. This is the first description showing reactivity to specific IgE for shrimp species X. kroyeri, popularly known as shrimp seven beards, in patients allergic to shrimp

Malkostrake Krebse zeigen im postnauplialen Keimstreif ein invariantes Zellteilungsmuster und eine Zelllinie. Embryonen eines Isopoden (Porcellio scaber) und eines Amphipoden (Orchestia cavimana) wurden bezüglich ihrer Zelllinie vergleichend Untersucht. Mittels immunhistochemischer Färbungen wurde das Expressionsmuster der Gene engrailed und Distal-less in Hinblick auf die Zelllinie und die Morphogenese der Segmente und der Beinentwicklung analysiert. Die Zelllinie wurde bei Porcellio scaber mit der Methode der 4D-Mikroskopie untersucht. Mit Zellablationsexperimenten wurden Abhängigkeiten der Zellen untereinander aufgezeigt. Die Ergebnisse dieser Untersuchungen zeigen: I. Die Genexpression von Distal-less und engrailed wird unabhängig von der Zelllinie reguliert. II. Die Bildung der konvergenten einästigen Beine im Thoraxbereich beider Krebse erfolgt durch unterschiedliche Regulation des Gens Distal-less - bei Orchestia cavimana wird die Expression des Gens in den lateralen Zellen abgeschaltet, während diese Zellen bei Porcellio scaber erst gar nicht Distal-less exprimieren. III. Die Anwendung des Systems der 4D-Mikroskopie zeigte unter anderem, dass in den vorderen Reihen nichtektoteloblastischen Ursprungs bei Porcellio scaber die Zelllinie variabel ist und eine Zellsortierung und Zellimmigration stattfindet. IV. Die Ähnlichkeit der Bildung dieser Reihen bei Porcellio scaber mit der der Tanaidaceen lässt auf ein Schwestergruppenverhältnis der Taxa Isopoda und Tanaidacea schliessen. Die Dissertation enthält fünf Videoaufnahmen als separate AVI-Dateien. / Malacostracan crustaceans show in their postnaupliar germ-band an invariant cleavage pattern and a cell-lineage. A comparative analysis of this cell-lineage in an Isopod (Porcellio scaber) and an amphipod (Orchestia cavimana) was done in this thesis. Immunohistochemical stainings of the gene products Distal-less and Engrailed were used, to show the relation of these genes to the morphogenesis of segments and legs. Further, the cell-lineage of Porcellio scaber was analyzed with a 4D-microscope system. Cell-ablation experiments were used to show regulational networks in the development of the germ-band. The results of this work show: I. The regulation of the genes Distal-less and engrailed is independent of the cell-lineage. II. The morphogenesis of the convergent monoramous limbs in the thorax is reflected by different expression patterns of the gene Distal-less - in Orchestia cavimana the expression of Distal-less is switched off in the lateral cells, in Porcellio scaber these cells do not start the Distal-less expression. III. The 4D-microscopy analysis show, that the cell-lineage in the cellrows wich have a non-ectoteloblastic origin is not invariant. In these rows of cells show cell sorting. IV. The formation of these rows in the isopod Porcellio scaber shows similarity to the formation in tanaidaceans. A sister group relationship of Tanaidacea and Isopoda is strongly supported. This dissertation contains five video recordings as separate AVI files.

Aquaculture represents a sustainable alternative to natural fisheries for provision of high quality, animal protein. Crustaceans make a significant contribution to global aquaculture production, of which decapods are the most economically important group. Among freshwater crayfish, the genus Cherax includes several species that have emerged as important culture species. A suite of favourable biological attributes, including fast growth and an omnivorous feeding habit, have contributed to establishment of successful culture of Cherax quadricarinatus (redclaw) in many countries. Aspects of redclaw production, however, remain relatively undeveloped, in particular feed formulation. To better understand the digestive processes and nutritional requirements of redclaw, this study examined the relationship between diet composition and digestive enzyme activity, growth performance and diet digestibility coefficients. The extent to which redclaw can efficiently utilise complex polysaccharides, such as cellulose, has been speculated on by authors who reported endogenous cellulase activity in this species. I evaluated the use of insoluble α-cellulose by redclaw, demonstrated that high dietary levels (30%) can significantly reduce the specific activity of selected digestive enzymes (amylase and cellulase), while also lowering apparent digestibility coefficients. Inclusion of α-cellulose above 12% also significantly reduced survival rate, specific growth rate and feeding efficiency in this organism which corresponds with low tolerance for insoluble fibre by other decapods. Even though redclaw possess endogenous cellulases, they appear to have only a limited capacity to utilise insoluble fibre in their diets. Further, I assessed the impact of different nutrient profiles on digestive enzyme activity, growth and tail muscle composition in redclaw. Purified diets containing varying levels of dietary protein significantly affected activity of digestive enzymes (protease, amylase and cellulase) and the composition of the tail muscle tissue. Redclaw have a relatively low protein requirement, which was reflected here, as little significant difference was observed in growth rates and the feed conversion ratio was only significantly affected by the lowest protein diet. Manipulation of the non-protein energy component in purified diets (protein to lipid ratio) had no effect on growth performance indices in redclaw. Digestive enzyme activity (protease) was however, strongly influenced by both the amount of protein and lipid in the diet and a significant correlation was observed between protease activity and growth performance indices. The findings here, provide preliminary data for consideration of digestive enzymes such as proteases as potential growth indicators for freshwater crayfish. These enzymes are already recognised as reliable biological indicators for comparison of digestive efficiency and potential growth rate in fish. The relationship between diet composition and digestive enzyme expression observed here, stress the need for further empirical evaluation of specific ingredients in artificial diets for redclaw. A range of single cell, plant and animal-based, agricultural products were assessed for their potential use in diets formulated for redclaw. Analysis of dietary supplements revealed that apparent digestibility of crude protein was generally higher for diets containing plant-based ingredients. A similar outcome was observed for digestibility coefficients of test ingredients. Ingredient type also had a significant effect on digestive enzyme activity. Importantly, a significant correlation was observed for enzyme activity and apparent digestibility coefficients. It appears that redclaw have the capacity to utilise nutrients from a broad range of dietary ingredients successfully including animal, single cell and in particular, plant matter in their diet. Taken together, the results presented here demonstrate that digestive enzyme activities in redclaw are significantly influenced by diet composition. I show clearly that the ability of redclaw to utilise various nutrients (measured as digestibility coefficients) is highly correlated with digestive enzyme activity. Finally, protease activity demonstrated a potential for use as an indicator of redclaw growth performance. The data presented here will contribute to development of better and cheaper feed formulations for use in redclaw aquaculture and have broader applications to freshwater crustacean culture. In particular, the potential for use of plant-based ingredients in aqua-feeds for redclaw will contribute to a more economically and environmentally sustainable redclaw culture.

La diversité génétique est un paramètre capital pour les populations comme pour les individus. Ainsi, l'hétérozygotie confère généralement un avantage de valeur sélective aux individus dans de nombreux taxa, et il existe divers processus de sélection sexuelle permettant d'optimiser l'hétérozygotie de la descendance. Nous avons testé ces hypothèses chez l'isopode terrestre Armadillidium vulgare. Nous avons pu mettre en évidence un meilleur succès reproducteur des mâles les plus hétérozygotes, qui peut résulter de la compétition intrasexuelle comme du choix de partenaire, ainsi que d'un choix pour un partenaire génétiquement dissimilaire. Ces deux processus ont pour conséquence d'augmenter l'hétérozygotie des descendants. Nous avons aussi décrit pour la première fois un fort taux de paternité multiple dans les populations naturelles comme expérimentales, augmentant la richesse allélique des portées et permettant à la sélection sexuelle post-copulatoire d'avoir lieu. De plus, nous avons pu observer que les animaux les plus hétérozygotes survivent mieux face à une infection bactérienne, probablement via une meilleure tolérance. Les individus les plus hétérozygotes sont également plus gros à âge équivalent, ce qui revêt une importance particulière pour les femelles puisqu'une grande taille leur confère une meilleure fécondité. Ces résultats suggèrent que divers mécanismes sont à l'origine du maintien de la diversité génétique dans les populations d'A. vulgare et confèrent aux individus une meilleure valeur sélective. Ainsi les populations de cet isopode terrestre possèdent vraisemblablement un potentiel adaptatif important permettant leur maintien à long terme. / Genetic diversity is a crucial parameter for both populations and individuals. As such, heterozygosity often confers a selective advantage to individuals in numerous taxa, and sexual selection processes can result in an optimisation of offspring heterozygosity. We tested these hypotheses in the terrestrial isopod Armadillidium vulgare. In this work, we highlighted a higher reproductive success for more heterozygous males, which could result from both intrasexual competition and mate choice, as well as a choice for a genetically dissimilar partner. These two processes result in an increase in offspring heterozygosity. Moreover, we described for the first time a high rate of multiple paternity in natural as well as in experimental populations, increasing brood allelic richness and allowing post-copulatory sexual selection processes. Besides, we showed that more heterozygous individuals survive better when confronted to a bacterial infection, probably through a better tolerance. More heterozygous individuals are also bigger at the same age, which is particularly important in females because a big size leads to a higher fecundity. These results suggest that various mechanisms result in genetic diversity maintenance in A. vulgare populations and confer a better fitness to individuals. Thereby, it is likely that populations of this terrestrial isopod possess a high adaptive potential enabling their long-term maintenance.

Made available in DSpace on 2014-06-11T19:26:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-05Bitstream added on 2014-06-13T18:29:24Z : No. of bitstreams: 1 guerra_al_me_sjrp.pdf: 4594193 bytes, checksum: 441ad838c49d255aeb995cc415bbc92e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os camarões do gênero Macrobrachium pertencem à família Palaemonidae. Habitam as proximidades do litoral e, também, ambientes de água doce. Com mais de cem espécies amplamente distribuídas pelas regiões tropicais e subtropicais do mundo, os palemonídeos possuem hábitos crípticos e noturnos. Particularmente na região noroeste do Estado de São Paulo, podemos encontrar várias espécies com importância econômica e ecológica consideráveis. Entretanto, existem poucos estudos na literatura relacionados ao conhecimento da biologia desses crustáceos. Assim, o presente trabalho objetivou analisar a variabilidade genética intra e interpopulacional, de amostras de duas espécies de camarões palemonídeos do gênero Macrobrachium (M. amazonicum e M. jelskii), coletadas em diferentes localidades, utilizando-se a análise das seqüências dos genes mitocondriais COI e rRNA 16S e, ainda, devido à problemática taxonômica existente entre essas duas espécies, também foi analisada a variabilidade genética interespecífica, utilizando-se os mesmos genes.. O cálculo dos índices de divergência genética intrapopulacionais apresentou valores baixos, refletindo uma provável estruturação genética destas populações. Apenas as populações de MjME e do CAUNESP apresentaram valores de divergência genética mais elevados, sugerindo um desequilíbrio na estruturação genética das mesmas, provavelmente causado por interferência antrópica e situação de cativeiro, respectivamente. Nas comparações interpopulacionais, envolvendo M. amazonicum, as taxas de divergência genética apresentaram uma ampla variação, também com média elevada. Os valores elevados nas comparações envolvendo a população do CAUNESP, permitiram descartar a hipótese da provável origem comum das populações de Macrobrachium, a partir de espécimes trazidos do Pará. Da mesma forma, as comparações... / The genus Macrobrachium (Bate, 1868) belongs to the Palaemonidae family. Their species are widely distributed in lakes, floodplains and rivers in tropical and subtropical regions of South America, having cryptic and nights habits. This genus presents nearly 210 known species with ecological and economic importance. Particulary in the northwestern state of São Paulo, we can find several species with considerable importance. However, there are few studies related to knowledge of the biology of these crustaceans. The aim this work was to analyze the genetic variability interpopulation, and interspecific of two Macrobrachium species (M. amazonicum and M. jelskii), using the mitochondrial gene sequence COI and 16S rRNA. Also, due to taxonomic problems between these two species we analyzed interspecific genetic variability, using the same genes. The intrapopulation rates of genetic divergence values were low, reflecting a probable genetic structure of these populations. Only populations MjME and CAUNESP showed higher divergence values, suggesting changes in their genetic structure of the same, probably caused by human interference and situation of captivity, respectively. In comparisons inferences involving M. amazonicum, rates of genetic divergence showed a wide range, also with high average. High values in comparisons involving the population of CAUNESP, allowed to reject the hypothesis of a probable common origin of populations the Macrobrachium specimens brought from State of Para. Interpopulation comparisons involving M. jelskii also showed high values of divergence, especially for the population collected from the Mendonça dam, whose genetic alteration in population structure was attributed to the frequent introduction of exotic specimens. The values of interspecific genetic divergence in the samples collected in the same geographic location were low for populations Adolfo (0.3%) ...(Complete abstract click electronic access below)

A atividade de neurônios em rajadas de disparo (bursts) é onipresente em sistemas nervosos. No entanto, o papel funcional dos bursts na codificação de informação ainda não é completamente compreendido. A dinâmica de burst tem sido intensivamente estudada em centros geradores de padrões (CPGs) que são exemplos clássicos de sistema nervoso autônomo em que a atividade em bursts está diretamente associada ao controle motor. Estudos recentes investigaram pequenas perturbações na dinâmica aparentemente periódica de neurônios com atividade em burst (bursters): padrões sutis nos tempos de disparo (spikes) dentro de um mesmo burst. Padrões de spikes intraburst (PSIBs) são tradicionalmente negligenciados por falta de relação com a função motora do CPG, no entanto, esses estudos mostraram que PSIBs são específicos para cada tipo de célula do CPG estomatogástrico de crustáceos e além disso, são capazes de refletir mudanças na conectividade da rede, indicando um possível papel na codificação de informação. Nesse trabalho, abordamos esse assunto investigando como um neurônio motor com atividade em bursts expressa informação a respeito de outros neurônios da rede através dos PSIBs. Realizamos experimentos registrando a atividade de neurônios pilóricos do gânglio estomatogástrico tanto na rede intacta como em uma rede híbrida na qual um neurônio pilórico interage em tempo real com um neurônio modelo através de uma sinapse artificial. Para inferir a sensibilidade dos PSIBs pós sinápticos aos pré-sinápticos desenvolvemos uma ferramenta de análise baseada em Teoria da Informação para encontrar padrões de máxima informação (ou seja, encontrar o bin que produz PSIBs de máxima entropia) e calcular informação mútua média entre eles (IMM) ao longo do burst de cada neurônio. Esta ferramenta também é potencialmente útil à análise de outros tipos de processos puntuais por fornecer um método de revelar informação oculta em padrões de eventos. Encontramos que um único neurônio motor é capaz de expressar no início de seu burst informação contida nos PSIBs do início do burst anterior do neurônio pré-sináptico. Esse fenômeno é observado em diferentes espécimes e espécies, o que sugere um mecanismo geral de codificação de informação. Além disso, esse efeito foi reproduzido em experimentos com uma rede híbrida, onde os estímulos pré-sinápticos são totalmente controlados, livre de qualquer influência de outros elementos no circuito. Esses resultados sugerem que a microestrutura dos padrões de disparo pré-sinápticos são codificadas se dá através de uma única sinapse, de maneira não linear e não homogênea nos PSIBs pós sinápticos. Dessa forma, neurônios motores são capazes de usar escalas de tempo diferentes para expressar dois tipos de informação: o ritmo de burst (associado à taxa de disparo) carrega informação sobre a contratação motora, enquanto que em uma escala de tempo muito menor, os PSIBs (associados à codificação temporal) expressam informação sobre o comportamento de outros neurônios do CPG. Além disso, encontramos que a informação dos PSIBs de um neurônio pilórico é codificada na estrutura temporal de disparo das unidades ativas registradas em um nervo do sistema estomatogástrico que projeta em áreas sensoriais do cérebro do animal. Assim, o mecanismo de codificação descrito pode ser parte de uma via de transmissão de informação previamente desconhecida, sugerindo que a codificação de informação através dos PSIBs poderia ser aproveitada para a regulação dos padrões de disparo em circuitos remotos pelo sistema nervoso central. / Burst firing is ubiquitous in nervous systems. However, the functional role of burst firing in information coding is mostly unknown. Bursting dynamics have been intensively studied in Central Pattern Generators (CPGs), classical examples of autonomous nervous circuits in which the most conspicuous bursting activity is clearly associated to motor function. Recent studies have investigated small perturbations embedded in the otherwise seemingly periodic bursting: the subtle intra-burst spike timing patterns (IBSPs), traditionally neglected for their lack of relation to the CPG motor function. Moreover, IBSPs were found to be cell-type specific and able to reflect changes in CPG connectivity, indicating a potential role in information coding. Here we addressed this matter by investigating how a bursting motor neuron expresses information about other neurons in the network. We performed experiments on the crustacean stomatogastric pyloric CPG, both in control conditions and when interacting in real-time with computer model neurons. The sensitivity of post- to pre-synaptic IBSPs was inferred by computing their average mutual information along each neuron burst. We found that a single motor neuron is able to express, at the beginning of its burst, information about the IBSPs of the beginning of the pre synaptic neuron\'s burst. This phenomenon is observed in different specimens and species, sugesting a genera information coding mechanism. Moreover, this effect was reproduced in a hybrid circuit, in which the presynaptic stimuli are completely controled by the experimenter free of any influence of other elements in the circuit. These results suggest that the presynaptic spiking microstructure are non-linearly and in homogeneously encoded through a single synapse in the post synaptic IBSPs. This way, motor neurons are able to use different time scales to express two types of information simultaneously: muscle contraction (related to bursting rate), and the behavior of other CPG neurons (in a much smaller timescale by using IBSPs as information carriers). Therefore, the coding mechanism described takes part in a previously unsuspected information pathway, providing evidence of the general physiological role of information coding through IBSPs in the regulation of neuronal _ring patterns in remote circuits by the central nervous system.

A alergia alimentar tem se tornado um problema crescente de saúde pública em muitos países e pode ser desencadeada por qualquer alimento. Em crianças os alimentos considerados mais alergênicos são leite de vaca e ovo e em adultos há uma alta frequência de alergia a frutos do mar, sendo camarão o marisco considerado mais alergênico. Clinicamente a alergia a camarão pode se manifestar em diferentes formas como dermatite atópica, angioedema ou até mesmo anafilaxia. Com base na história clínica e avaliação de resultados de exames complementares foram selecionados 18 indivíduos alérgicos a camarão e 9 não alérgicos como grupo controle. Foram realizados testes in vitro para dosagem de IgE especifica no soro e teste cutâneo. Para reações ocorridas há mais de um ano foi realizada provocação oral para confirmação diagnóstica. O soro de todos os indivíduos do estudo foram testados em Western Blotting 1D e 2D com extrato de carne de camarão e casca separadamente da espécie Xiphopenaeus kroyeri, que possui grande importância por ser altamente consumida em nosso país além de estar entre as dez estirpes mais capturadas no mundo. Ainda assim não está presente em nenhum teste comercial disponível e não há nenhum alérgeno descrito para o mesmo. A caracterização de suas moléculas alergênicas é importante para melhor auxilio no diagnóstico e tratamento de pacientes alérgicos. As proteínas que apresentaram reatividade IgE especifica foram submetidas a espectrometria de massas para identificação. Foi possível identificar alguns homólogos de alérgenos de outras espécies de camarão como, tropomiosina, arginina quinase, proteína sarcoplasmática de ligação ao cálcio, actina, cadeia leve e pesada de miosina e hemocianina. Encontramos um possível novo alérgeno denominado como citocromo c oxidase (subunidade I) que não foi descrito anteriormente como proteína alergênica. Analisando sensibilidade e valor preditivo positivo das nossas proteínas sugerimos que algumas delas podem ser boas candidatas como futuros marcadores diagnósticos para alergia a camarão. Quando comparamos o perfil de proteínas reativas em carne e casca de camarão não observamos diferenças significativas entre elas. Essa é a primeira descrição de alergia para a espécie de camarão X. kroyeri, popularmente conhecido como camarão sete barbas, mostrando reatividade a IgE especifica em pacientes alérgicos a camarão / Food allergy has become a growing problem of public health in many countries, and can be triggered by any food. In children the most allergenic foods are cow\'s milk and egg; in adults there are high frequencies of allergy to seafood, and shrimps are considered the most allergenic seafood. Clinically, shrimp allergy can manifest itself in different forms, such as atopic dermatitis, angioedema or even anaphylaxis. Based on the clinical history and evaluation of the tests, we selected eighteen subjects that were allergic to shrimp, and nine non-allergic to shrimp as a control group. In vitro tests were performed to IgE specific dosage and cutaneous test with commercial extract. When reactions occurred more than one year before oral provocation test was performed for diagnostic confirmation. The serum of all individuals were tested in Western Blotting 1D and 2D with the shrimp meat and shell extracts separately from the species Xiphopenaeus kroyeri, which has great importance since is highly consumed in the Southeast region of our country and is among the top ten captured species in the world. Nevertheless, there are no commercial clinical tests available for it, and there is no specific allergen described, both of them would help the diagnosis and treatment of allergic patients. Proteins that showed specific IgE reactivity were submitted to mass spectrometry for identification. We identified some homologues allergens from other shrimp species such as tropomyosin, arginine kinase, calcium-binding sarcoplasmic protein, actin, myosin heavy chain and hemocyanin. We founded a possible new allergen called cytochrome c oxidase (subunit I), that was never previously described as an allergenic protein. Analyzing sensitivity and positive predictive value of our proteins we suggest that some of them may be good candidates as future diagnostic markers for shrimp allergy. When comparing the reactive proteins profile in shrimp meat and shell, we did not observe significant differences between them. This is the first description showing reactivity to specific IgE for shrimp species X. kroyeri, popularly known as shrimp seven beards, in patients allergic to shrimp

La différenciation sexuelle des Isopodes dépend d'une hormone sexuelle protéique, l'hormone androgène (HA), caractéristique des Malacostracés. Cet Insulin-Like Peptide suffit à induire par sa présence la différenciation mâle de ces Crustacés. Nous avons identifié in silico le transporteur circulant de l'HA, l'IGFBP-rP1, chez de nombreuses espèces d'Isopodes ainsi qu'à l'échelle des Crustacés. De la même façon, nous avons identifié deux récepteurs transmembranaires, l'IR1 et l'IR2, issus d'une duplication de gène spécifique des Malacostracés. Les patrons d'expression de ces gènes ont été étudiés sur notre espèce modèle, Armadillidium vulgare. Av-IGFBP-rP1 et Av-IR1 sont exprimés de manière ubiquiste et tout au long du développement. Av-IR2 est aussi exprimé à chaque stade de la différenciation mais ce transcrit est quasi-spécifique des glandes androgènes et ovaires. Une approche par ARNi a confirmé l'implication de ces trois protéines dans la voie de signalisation de l'HA. En effet, l'inhibition de l'HA, Av-IGFBP-rP1 et Av-IR1 provoquent l'hypertrophie des glandes androgènes, suggérant leur implication dans une boucle de rétro-contrôle de l'HA. L'inhibition de Av-IR2 semble seulement provoquer la différenciation d'ouvertures génitales femelles. Ces phénotypes sont comparables à ceux des intersexués mâles induits par la bactérie féminisante endogène Wolbachia. Nous montrons cependant que la bactérie altère seulement l'expression de l'HA et pas celle des récepteurs. Enfin, nous avons testé l'effet du bisphénol A mais nous n'observons pas d'altération de la différenciation sexuelle des larves lors d'expositions à ce perturbateur endocrinien exogène. / Sexual differentiation in Isopods relies on a proteinaceous sex hormone called androgenic hormone (AH), specific to Malacostracans. This Insulin-Like Peptide induces male differentiation by its mere presence in these Crustaceans. We identified in silico the circulating carrier of the AH, called IGFBP-rP1, in many Isopod species, but also on the crustacean scale. Similarly, we identified two transmembrane receptors, IR1 and IR2, coming from a gene duplication specific to Malacostracans. The expression patterns of these genes were investigated in our model species, Armadillidium vulgare. Av-IGFBP-rP1 and Av-IR1 are broadly expressed in the animal and throughout development. Av-IR2 is also expressed at each developmental stage but this transcript is almost specific to androgenic glands and ovaries. An RNAi approach has confirmed the implication of these three proteins in the AH signalling pathway. Indeed, the inhibition of AH, Av-IGFBP-rP1 and Av-IR1 induces androgenic gland hypertrophy, suggesting their implication in an AH feedback loop. Av-IR2 inhibition seems to provoke the differentiation of female genital apertures only. These phenotypes are similar to those of male intersexes induced by the endogenous feminizing bacterium Wolbachia. Yet, we show that the bacterium alters the expression of the AH only and not the one of its receptors. Finally, we have tested the effect of bisphenol A but we observe no alteration of the sexual differentiation in larvae upon exposition to this exogenous endocrine disruptor.

The most abundant organic compound produced by plants is cellulose, however it has long been accepted that animals do not secrete the hydrolytic enzymes required for its degradation, but rely instead on cellulases produced by symbiotic microbes. The recent discovery of an endogenous cDNA transcript encoding a putative GHF9 endoglucanase in the parastacid crayfish Cherax quadricarinatus (Byrne et al., 1999) suggests that similar cellulase genes may have been inherited by a range of crustacean taxa. In this study, the evolutionary history of the C. quadricarinatus endoglucanase gene and the presence of additional GHF9 genes in other decapod species were investigated. The activity of endoglucanase and endoxylanase enzymes within several cultured decapod species were also compared. The evolutionary history of the C. quadricarinatus endoglucanase gene was assessed by comparing intron/exon structure with that of other invertebrate and plant GHF9 genes. The coding region of the gene was found to be interrupted by eleven introns ranging in size from 102-902 bp, the position of which was largely conserved in both termite and abalone GHF9 genes. These structural similarities suggest GHF9 genes in crustaceans and other invertebrate taxa share a common ancestry. In addition, two introns were observed to share similar positions in plant GHF9 genes, which indicates this enzyme class may have been present in ancient eukaryote organisms. The presence of GHF9 genes in C. quadricarinatus and various other decapod species was then explored via degenerate primer PCR. Two distinct GHF9 gene fragments were determined for C. quadricarinatus and several other Cherax and Euastacus parastacid freshwater crayfish species, and a single GHF9 gene fragment was also determined for the palaemonid freshwater prawn Macrobrachium lar. Phylogenetic analyses of these fragments confirmed the presence of two endoglucanase genes within the Parastacidae, termed EG-1 and EG-2. The duplication event that produced these two genes appears to have occurred prior to the evolution of freshwater crayfish. In addition, EG-2 genes appear to have duplicated more recently within the Cherax lineage. The presence of multiple GHF9 endoglucanase enzymes within the digestive tract of some decapod species may enable more efficient processing of cellulose substrates present in dietary plant material. Endoglucanase and endoxylanase enzyme activities were compared in several parastacid crayfish and penaeid prawn species using dye-linked substrates. Endoglucanase activity levels were higher in crayfish compared with prawn species, which corresponds with the known dietary preferences of these taxa. Endoglucanase temperature and pH profiles were found to be very similar for all species examined, with optimum activity occurring at 60°C and pH 5.0. These results suggest endoglucanase activity in penaeid prawns may also be derived from endogenous sources. Additional in vitro studies further demonstrated crayfish and prawn species liberate comparable amounts of glucose from carboxymethyl-cellulose, which indicates both taxa may utilise cellulose substrates as a source of energy. Endoxylanase temperature and pH profiles were also similar for all crayfish species examined, with optimal activity occurring at 50°C and pH 5.0. These results suggest xylanase activity in crayfish may originate from endogenous enzymes, although it is unclear whether this activity is derived from GHF9 enzymes or a different xylanase enzyme class. In contrast, no endoxylanase activity was detected in the three prawn species examined. Together, these findings suggest a wide range of decapod crustacean species may possess endogenous GHF9 endoglucanase genes and enzymes. Endoglucanases may be secreted by various decapod species in order to digest soluble or amorphous cellulose substrates present in consumed plant material. Further biochemical studies may confirm the presence and functional attributes of additional endoglucanase genes and enzymes in decapods, which may ultimately assist in the design of optimal plant based crustacean aquaculture feeds.