L'agressivité est un comportement fréquemment observé chez les animaux et qui est notamment modulé par la sérotonine (5-HT) et les hormones stéroïdes. Cependant, même si des hypothèses évoquent une interaction possible entre ces molécules dans la régulation des comportements agressifs, peu d’études permettent de les confirmer. De plus les mécanismes neuronaux sous-tendant ces comportements agressifs sont encore peu connus. En utilisant comme modèle l'écrevisse de Louisiane, très étudiée pour son comportement agressif et ses hiérarchies sociales, ce travail montre comment la 5-HT et les hormones stéroïdes modifient les réseaux neuronaux et contrôlent ainsi l'agressivité de ces animaux. La mue des écrevisses est contrôlée par une hormone stéroïde appelée 20-hydroxyecdysone (20E), dont la concentration augmente pendant la prémue. Durant cette période, la 20E diminue à la fois l’agressivité des écrevisses et la locomotion. L’activité du réseau locomoteur, un des supports essentiels de l'agressivité (permettant les approches, les attaques… ou les fuites) et son intégration sensori-motrice sont fortement inhibés également. Cette inhibition passe par une réduction de la réactivité des réseaux, notamment via la baisse de résistance d’entrée (Rin) des motoneurones. En présence de 20E, la concentration de 5-HT augmente fortement dans l’organisme par l’inhibition présumée de la voie de dégradation de la 5-HT. Nous supposons comme déjà décrit sur d’autres réseaux que cette augmentation bloquerait les réseaux dans un état inhibée. Cet état inhibée serait maintenu par la baisse de Rin, causée par la libération de 5-HT sur la partie périphérique des MN principalement inhibitrice. / In animal kingdom, aggressivity is a very frequent behavior obvious. Serotonin (5-HT) and steroid hormones modulate this behavior. However, even if several hypothesis raise that one interaction is possible between these molecules to control aggressivity, no study can confirm it. Moreover, neuronal actions behind this behavior stay unclear. In this study, we show how 5-HT and steroid hormones can regulate neural networks and aggressivity. Crayfish molting is regulated by a steroid hormone, called 20-hydroxyecdysone (20E) and its concentration increases during pre-molt period. 20E decreases crayfish aggressivity and locomotion. Locomotors activities and sensory-motor integration are also inhibited during pre-molt. This inhibition is caused by a drop of neural reactivity because input resistance of motoneurons decreases. After injection of 20E or during pre-molt period, 5-HT concentration increase. We think this increase would block networks in inhibition state during pre-molt.

A cutícula dos insetos é composta principalmente por uma variedade de proteínas que interagem com filamentos de quitina, um polímero de N-acetilglicosamina, para formar um envoltório rígido que protege e dá forma ao organismo. O crescimento dos insetos depende da renovação periódica da cutícula, que se desprende durante a apólise e é digerida enquanto a epiderme sintetiza uma nova cutícula substituta. Tal renovação caracteriza a muda e metamorfose e é coordenada por hormônios, com destaque para os ecdisteróides. O atual trabalho objetivou caracterizar a expressão diferencial de genes do tegumento (cutícula e epiderme subjacente), além de elucidar aspectos de regulação e função no contexto da muda e metamorfose, com foco nos genes codificadores de proteínas estruturais e enzimas cuticulares. Para este fim, utilizamos o tegumento de fases específicas da muda pupal-adulta, isto é, de pupas (Pw), de pupas em apólise (Pp) e de adultas faratas (Pbl) para análises de microarrays de cDNA. As análises dos microarrays mostraram 761 e 1173 genes diferencialmente expressos nos tegumentos de adultas faratas (Pbl) em comparação com pupas (Pw) ou pupas em apólise (Pp), respectivamente. A categorização destes genes, segundo os critérios do Gene Ontology, distinguiu totalmente o tegumento de adultas faratas (Pbl) dos tegumentos de pupas (Pw) ou pupas em apólise (Pp) tanto em relação ao critério Processo Biológico quanto em relação à Função molecular, evidenciando grande mudança na expressão gênica durante a construção do exoesqueleto definitivo nas adultas faratas (Pbl). Os microarrays mostraram aumento estatisticamente significante da expressão de 24 genes cuticulares no tegumento de adultas faratas. Este resultado foi validado por RT-PCR em tempo real (qRT-PCR) para 23 destes genes (AmelCPR3, AmelCPR4, AmelCPR6, AmelCPR14, AmelCPR15, AmelCPR17, AmelCPR23, AmelCPR24, AmelCPR25, AmelCPR28, AmelCPR29, AmelCPR30, apd-1, apd-2, apd-3, CPLCP1, Am-C, Am-D, AmelTwdl1, AmelTwdl2, GB12449, GB12811 e GB11550), e por RT-PCR semiquantitativa para o gene Amlac2. Além disto, a maior expressão de outros 2 genes cuticulares (AmelCPR1 e AmelCPR2) em adultas faratas foi demonstrada por qRT-PCR. Estes genes cuticulares positivamente regulados no tegumento de adultas faratas (Pbl) devem estar envolvidos com a formação e diferenciação do exoesqueleto definitivo. O aumento da expressão gênica neste período da muda (Pbl) é regulado pela variação do título de ecdisteróides e ocorre enquanto o título deste hormônio decai, após ter atingido o pico indutor da apólise na fase de desenvolvimento precedente (Pp). Ao contrário, as análises por qRT-PCR mostraram que 2 outros genes cuticulares (AmelCPF1 e AmelCPR1) são negativamente regulados no tegumento de adultas faratas em comparação com pupas, sugerindo que são específicos de cutícula pupal. Estes genes foram inibidos pelo aumento dos níveis de ecdisteróides, que induz a apólise. Vinte e um entre os 24 genes cuticulares diferencialmente expressos nos microarrays codificam proteínas pertencentes às famílias CPF, CPR, Apidermina, CPLCP, Análoga a peritrofina e Tweedle. Os outros 3 genes diferencialmente expressos (GB12449, GB12811, GB11550) não tinham sido ainda caracterizados como genes cuticulares. Dois deles, GB12449 e GB12811, foram sequenciados para validação da predição e para a caracterização das respectivas estruturas genômicas. Experimentos de hibridação in situ com sonda fluorescente (FISH) nos permitiram localizar altos níveis de transcritos destes genes no citoplasma de células da epiderme de adultas faratas, sugerindo fortemente sua natureza cuticular e envolvimento na construção do exoesqueleto definitivo. O presente estudo consiste na primeira análise global de expressão de genes do tegumento de uma espécie de himenóptero social. Os resultados apresentados levaram à identificação de genes com expressão associada à muda pupal-adulta e formação do exoesqueleto definitivo. Este trabalho contribui com novos dados moleculares para o aprofundamento do conhecimento da metamorfose de A. mellifera. / The insect cuticle is mainly composed of proteins that interact with chitin filaments to form a rigid structure that protects and shapes the organism. Insects grow through the periodic renewal of the cuticle, which is shed at each apolysis episode, and subsequently digested while the epidermis synthesizes the cuticle of the next stage. These molting events are coordinated by hormones, mainly ecdysteroids. The current work aimed to characterize differential gene expression in the integument (cuticle and underlying epidermis) during the ecdysteroid-regulated pupal-to-adult molt. Special attention was given to the structure and expression of genes encoding proteins and enzymes involved in cuticle formation and differentiation. To achieve these goals, we used thoracic integument of newly-ecdysed pupae (Pw), pupae in apolysis (Pp) and pharate adults (Pbl) in cDNA microarray analyses. The microarray analysis showed 761 and 1173 differentially expressed genes in the pharate adult integument (Pbl) in comparison to pupae (Pw) or pupae in apolysis (Pp), respectively. Gene Ontology terms for Biological Process and Molecular Function completely distinguished the integument of pharate adults (Pbl) from the integument of pupae (Pw) or pupae in apolysis (Pp). The microarray analysis discriminated 24 cuticular genes with a significant expression increase in the pharate adult integument. This was validated by real time RT-PCR analysis (qRT-PCR) for 23 of these genes (AmelCPR3, AmelCPR4, AmelCPR6, AmelCPR14, AmelCPR15, AmelCPR17, AmelCPR23, AmelCPR24, AmelCPR25, AmelCPR28, AmelCPR29, AmelCPR30, apd-1, apd-2, apd-3, CPLCP1, Am-C, Am-D, AmelTwdl1, AmelTwdl2, GB12449, GB12811 and GB11550), and by semiquantitative RT-PCR for Amlac2. In addition, the increased expression of other two cuticular genes (AmelCPR1 and AmelCPR2) was confirmed by qRT-PCR. These up-regulated cuticular genes in pharate adult integument apparently are involved in adult cuticle formation and differentiation, which occurs while the ecdysteroids titers decay, after reaching the peak that induces apolysis in the preceding phase (Pp). In contrast, two cuticular genes (AmelCPF1 e AmelCPR1) were confirmed by qRT-PCR analysis as negatively regulated in the integument of pharate adults compared to pupae, suggesting that they are specific to pupal cuticle. Therefore, these genes were inhibited by the increasing ecdysteroid levels that induce apolysis. Twenty one of the 24 cuticular genes differentially expressed in the microarrays encode proteins belonging to the CPF, CPR, Apidermin, CPLCP, Analogous to peritrofins and Tweedle families. The other three differentially expressed genes (GB12449, GB12811, GB11550) had not yet been assigned as cuticular genes. Two of them (GB12449 and GB12811) were sequenced, thus allowing prediction validation and gene structure characterization. In situ hybridization experiments using fluorescent probe (FISH) localized high expression of these genes in the pharate adult epidermis, strongly suggesting their involvement in the construction of the adult exoskeleton. This study is the first global gene expression analysis of the integument from a social hymenopteran species. The expression of genes in the integument was associated to the molting process and to the adult exoskeleton formation. This work contributes with new molecular data for a deeper understanding of A. mellifera metamorphosis.

A cutícula dos insetos é composta principalmente por uma variedade de proteínas que interagem com filamentos de quitina, um polímero de N-acetilglicosamina, para formar um envoltório rígido que protege e dá forma ao organismo. O crescimento dos insetos depende da renovação periódica da cutícula, que se desprende durante a apólise e é digerida enquanto a epiderme sintetiza uma nova cutícula substituta. Tal renovação caracteriza a muda e metamorfose e é coordenada por hormônios, com destaque para os ecdisteróides. O atual trabalho objetivou caracterizar a expressão diferencial de genes do tegumento (cutícula e epiderme subjacente), além de elucidar aspectos de regulação e função no contexto da muda e metamorfose, com foco nos genes codificadores de proteínas estruturais e enzimas cuticulares. Para este fim, utilizamos o tegumento de fases específicas da muda pupal-adulta, isto é, de pupas (Pw), de pupas em apólise (Pp) e de adultas faratas (Pbl) para análises de microarrays de cDNA. As análises dos microarrays mostraram 761 e 1173 genes diferencialmente expressos nos tegumentos de adultas faratas (Pbl) em comparação com pupas (Pw) ou pupas em apólise (Pp), respectivamente. A categorização destes genes, segundo os critérios do Gene Ontology, distinguiu totalmente o tegumento de adultas faratas (Pbl) dos tegumentos de pupas (Pw) ou pupas em apólise (Pp) tanto em relação ao critério Processo Biológico quanto em relação à Função molecular, evidenciando grande mudança na expressão gênica durante a construção do exoesqueleto definitivo nas adultas faratas (Pbl). Os microarrays mostraram aumento estatisticamente significante da expressão de 24 genes cuticulares no tegumento de adultas faratas. Este resultado foi validado por RT-PCR em tempo real (qRT-PCR) para 23 destes genes (AmelCPR3, AmelCPR4, AmelCPR6, AmelCPR14, AmelCPR15, AmelCPR17, AmelCPR23, AmelCPR24, AmelCPR25, AmelCPR28, AmelCPR29, AmelCPR30, apd-1, apd-2, apd-3, CPLCP1, Am-C, Am-D, AmelTwdl1, AmelTwdl2, GB12449, GB12811 e GB11550), e por RT-PCR semiquantitativa para o gene Amlac2. Além disto, a maior expressão de outros 2 genes cuticulares (AmelCPR1 e AmelCPR2) em adultas faratas foi demonstrada por qRT-PCR. Estes genes cuticulares positivamente regulados no tegumento de adultas faratas (Pbl) devem estar envolvidos com a formação e diferenciação do exoesqueleto definitivo. O aumento da expressão gênica neste período da muda (Pbl) é regulado pela variação do título de ecdisteróides e ocorre enquanto o título deste hormônio decai, após ter atingido o pico indutor da apólise na fase de desenvolvimento precedente (Pp). Ao contrário, as análises por qRT-PCR mostraram que 2 outros genes cuticulares (AmelCPF1 e AmelCPR1) são negativamente regulados no tegumento de adultas faratas em comparação com pupas, sugerindo que são específicos de cutícula pupal. Estes genes foram inibidos pelo aumento dos níveis de ecdisteróides, que induz a apólise. Vinte e um entre os 24 genes cuticulares diferencialmente expressos nos microarrays codificam proteínas pertencentes às famílias CPF, CPR, Apidermina, CPLCP, Análoga a peritrofina e Tweedle. Os outros 3 genes diferencialmente expressos (GB12449, GB12811, GB11550) não tinham sido ainda caracterizados como genes cuticulares. Dois deles, GB12449 e GB12811, foram sequenciados para validação da predição e para a caracterização das respectivas estruturas genômicas. Experimentos de hibridação in situ com sonda fluorescente (FISH) nos permitiram localizar altos níveis de transcritos destes genes no citoplasma de células da epiderme de adultas faratas, sugerindo fortemente sua natureza cuticular e envolvimento na construção do exoesqueleto definitivo. O presente estudo consiste na primeira análise global de expressão de genes do tegumento de uma espécie de himenóptero social. Os resultados apresentados levaram à identificação de genes com expressão associada à muda pupal-adulta e formação do exoesqueleto definitivo. Este trabalho contribui com novos dados moleculares para o aprofundamento do conhecimento da metamorfose de A. mellifera. / The insect cuticle is mainly composed of proteins that interact with chitin filaments to form a rigid structure that protects and shapes the organism. Insects grow through the periodic renewal of the cuticle, which is shed at each apolysis episode, and subsequently digested while the epidermis synthesizes the cuticle of the next stage. These molting events are coordinated by hormones, mainly ecdysteroids. The current work aimed to characterize differential gene expression in the integument (cuticle and underlying epidermis) during the ecdysteroid-regulated pupal-to-adult molt. Special attention was given to the structure and expression of genes encoding proteins and enzymes involved in cuticle formation and differentiation. To achieve these goals, we used thoracic integument of newly-ecdysed pupae (Pw), pupae in apolysis (Pp) and pharate adults (Pbl) in cDNA microarray analyses. The microarray analysis showed 761 and 1173 differentially expressed genes in the pharate adult integument (Pbl) in comparison to pupae (Pw) or pupae in apolysis (Pp), respectively. Gene Ontology terms for Biological Process and Molecular Function completely distinguished the integument of pharate adults (Pbl) from the integument of pupae (Pw) or pupae in apolysis (Pp). The microarray analysis discriminated 24 cuticular genes with a significant expression increase in the pharate adult integument. This was validated by real time RT-PCR analysis (qRT-PCR) for 23 of these genes (AmelCPR3, AmelCPR4, AmelCPR6, AmelCPR14, AmelCPR15, AmelCPR17, AmelCPR23, AmelCPR24, AmelCPR25, AmelCPR28, AmelCPR29, AmelCPR30, apd-1, apd-2, apd-3, CPLCP1, Am-C, Am-D, AmelTwdl1, AmelTwdl2, GB12449, GB12811 and GB11550), and by semiquantitative RT-PCR for Amlac2. In addition, the increased expression of other two cuticular genes (AmelCPR1 and AmelCPR2) was confirmed by qRT-PCR. These up-regulated cuticular genes in pharate adult integument apparently are involved in adult cuticle formation and differentiation, which occurs while the ecdysteroids titers decay, after reaching the peak that induces apolysis in the preceding phase (Pp). In contrast, two cuticular genes (AmelCPF1 e AmelCPR1) were confirmed by qRT-PCR analysis as negatively regulated in the integument of pharate adults compared to pupae, suggesting that they are specific to pupal cuticle. Therefore, these genes were inhibited by the increasing ecdysteroid levels that induce apolysis. Twenty one of the 24 cuticular genes differentially expressed in the microarrays encode proteins belonging to the CPF, CPR, Apidermin, CPLCP, Analogous to peritrofins and Tweedle families. The other three differentially expressed genes (GB12449, GB12811, GB11550) had not yet been assigned as cuticular genes. Two of them (GB12449 and GB12811) were sequenced, thus allowing prediction validation and gene structure characterization. In situ hybridization experiments using fluorescent probe (FISH) localized high expression of these genes in the pharate adult epidermis, strongly suggesting their involvement in the construction of the adult exoskeleton. This study is the first global gene expression analysis of the integument from a social hymenopteran species. The expression of genes in the integument was associated to the molting process and to the adult exoskeleton formation. This work contributes with new molecular data for a deeper understanding of A. mellifera metamorphosis.

No description available.

No description available.

The aim of this study was to determine whether functional ecdysone response elements (EcREs) exist within the genome of Brugia malayi, a parasitic nematode that causes lymphatic filariasis. The hypothesis that EcREs exist in B. malayi stemmed from previous demonstration of a functional ecdysone response system in B. malayi (Tzertzinis et al., 2010). Real-time PCR (qPCR) experiments were conducted to measure gene expression levels for twelve genes proximal to five putative EcREs in 20-OH ecdysone treated and untreated B. malayi embryos. Seven genes showed consistent upregulation with 20-OH ecdysone treatment. Each of the five putative EcREs had at least one proximal gene consistently upregulated, suggesting that all five might be functional EcREs. One of the genes consistently upregulated in the qPCR experiments, Bm1_48650, codes for a MIZ zinc finger family protein, a likely transcription factor. Transgenic ecdysone induction assay experiments were conducted using embryos transiently transfected with a reporter construct driven by the EcRE-containing promoter of Bm1_48650. Significantly higher mean reporter gene activity (~3.5-fold) was seen in 20-OH ecdysone treated versus untreated embryos. In another set of transgenic ecdysone induction assays, the EcRE motif in the Bm1_48650 promoter was completely mutated, and this construct was tested in 20-OH ecdysone treated and untreated embryos. The mean reporter gene activity for the treated and untreated embryos transfected with the mutant constructs did not differ significantly from the untreated embryos transfected with the native EcREcontaining promoter construct. These results showed that the EcRE in the promoter of Bm1_48650 is necessary for regulating gene expression in response to 20-OH ecdysone. This study substantiates previously discovered evidence of a functional ecdysone response system in B. malayi, which could potentially serve as a target for drug discovery for lymphatic filariasis.

Brassinosteroids and ecdysteroid are naturally occuring chemical compounds in plants. The aim of this study was to show whether the application of exogenous steroids such as brassinosteroids (24-epibrassinolide, 28-homobrassinolide, 24-epicastasterone) and ecdysteroid (20-hydroxyecdysone) can affect the morphological parameters and primary photosyntetic processes of selected monocotyledons that was barley, wheat, maize and sorghum. Non-destructive method for measuring of fast kinetics of chlorophyll fluorescence in investigated plants was used. Analysis of primary photosynthetic processes was realized in five time periods from the application of exogenous steroids on the two different old leaves. The response to the treatment by exogenous steroid was different species by plant species. One week after the application of exogenous steroids plants showed differences in their morphological parameters but most of them were not signifficant. The most steroid-sensitive plant was wheat morphological parameters of were significantly different from untreated control plants. No change in maximum quantum yield of photosystem II to the application of exogenous steroid in plants of Sorghum bicolor L. was detected. In the other examined plant species changes in photosynthesis parameters were detected which...