Análise Funcional Comparativa do Relógio Circadiano de Drosophila melanogaster e insetos vetores

Submitted by Anderson Silva ([email protected]) on 2012-10-19T19:07:47Z No. of bitstreams: 1 antonio_c_a_meirelesfilho_ioc_bcm_0044_2008.pdf: 2486014 bytes, checksum: 619a0dcb233abdf48640585c364627e4 (MD5)Made available in DSpace on 2012-10-19T19:07:48Z (GMT). No. of bitstreams: 1 antonio_c_a_meirelesfilho_ioc_bcm_0044_2008.pdf: 2486014 bytes, checksum: 619a0dcb233abdf48640585c364627e4 (MD5) Previous issue date: 2008Research Institute Of Molecular Pathology Dr. Bohr-Gasse 7. Vienna, VIE, AustriaDiversos organismos apresentam variações no comportamento e na fisiologia que são controladas por um relógio biológico interno. O flebotomíneo Lutzomyia longipalpis (Diptera: Psychodidae), o principal vetor da leishmaniose visceral nas Américas, é um inseto hematófago com atividade crepuscular/noturna. A hematofagia, crítica na transmissão da doença, está restrita a uma determinada hora do dia, certamente conseqüência do controle do marcapasso circadiano. Apesar da importância dos ritmos circadianos na dinâmica da transmissão da doença, pouco se sabe sobre seu controle molecular em insetos vetores. Neste trabalho descrevemos algumas propriedades do relógio circadiano de L. longipalpis. Comparado a Drosophila melanogaster, os genes period (per) e timeless (tim), dois elementos negativos da retroalimentação negativa, apresentam padrão similar de expressao de RNAm. Por outro lado, a expressão de Clock (Clk) e cycle (cyc), dois elemetos positivos, diferem entre as duas espécies, sugerindo que as diferenças de fase de suas expressões possam estar associadas às diferenças observadas no ritmo de atividade circadiana. Além disso, nós observamos uma redução da atividade locomotora após o repasto sanguíneo, que é correlacionada com uma diminuição dos níveis de expressão de per and tim. Apesar de muitos aspectos do marcapasso molecular serem conservados em animais, algumas diferencas entre L. longipalpis e D. melanogaster sugeriram que o relógio circadiano de moscas de fruta divergiu bastante durante a evolução. Por exemplo, enquanto em moscas o domínio de transativação do elemento positivo reside em CLK, em L. longipalpis e todos outros animais analisados até o momento ele fica em CYC. Dessa forma, parece que durante o processo evolutivo houve uma transferência funcional do domínio de transativação de CLK para CYC na linhagem de Drosophila. Para elucidar a evolução funcional do relógio circadiano de Drosophila nós testamos a hipótese de que CLK e CYC tenham trocado o domínio de transativação durante a evolução. Nossos estudos revelaram que o relógio de Drosophila pode funcionar da mesma maneira que o de mamíferos e que CRYPTOCHROME, além do seu papel bem descrito na fotorecepção, pode ter tido um papel ancestral no mecanismo molecular do marcapasso de Drosophila.A diversity of organisms has circadian variations of behavior and physiology that are controlled by an internal biological clock. The sand fly Lutzomyia longipalpis (Diptera: Psychodidae) is a crepuscular/nocturnal blood-sucking insect that is the main vector of visceral leishmaniasis in the Americas. Blood feeding, which is critical to disease transmission, is tightly adjusted to a specific time of day and it is therefore certainly controlled by the circadian pacemaker. Despite the importance of circadian rhythms in the dynamics of disease transmission, very little is known about its molecular control in insect vectors. In this work we describe some features of the circadian clock of L. longipalpis. Compared to Drosophila melanogaster, sandfly period (per) and timeless (tim), two negative elements of the feedback loop, show similar peaks of mRNA abundance. On the other hand, the expression of Clock (Clk) and cycle (cyc), two positive elements, differs between the two species, raising the possibility that the different phases of their expression could be associated with the observed differences in circadian activity rhythms. In addition, we show a reduction in locomotor activity after a blood meal, which is correlated with downregulation of per and tim expression levels. Although many aspects of the molecular pacemaker are conserved in animals, some differences among L. longipalpis and D. melanogaster suggested that the fruit fly circadian clock have strongly diversified during the course of evolution. For example, while in flies the transactivation domain of the positive element resides in CLK, in L. longipalpis and all other animals analyzed so far it is in CYC. Therefore, it seems that during the course of evolution a functional transference of the transactivation domain from CYC to CLK occurred in the Drosophila lineage. To shed light into the functional evolution of the Drosophila circadian clock we tested the hypothesis that CLK and CYC have swapped the transactivation domain during the course of evolution. Our studies revealed that Drosophila can sustain a mammalian-like pacemaker and that CRYPTOCHROME, besides its well described role in Drosophila photoreception, might have had an ancient role in the fruit fly clockwork mechanism

A parallelized, automated platform enabling individual or sequential ChIP of histone marks and transcription factors

Despite its popularity, chromatin immunoprecipitation followed by sequencing (ChIP-seq) remains a tedious (>2 d), manually intensive, low-sensitivity and low-throughput approach. Here, we combine principles of microengineering, surface chemistry, and molecular biology to address the major limitations of standard ChIP-seq. The resulting technology, FloChIP, automates and miniaturizes ChIP in a beadless fashion while facilitating the downstream library preparation process through on-chip chromatin tagmentation. FloChIP is fast (<2 h), has a wide dynamic range (from 106 to 500 cells), is scalable and parallelized, and supports antibody- or sample-multiplexed ChIP on both histone marks and transcription factors. In addition, FloChIP's interconnected design allows for straightforward chromatin reimmunoprecipitation, which allows this technology to also act as a microfluidic sequential ChIP-seq system. Finally, we ran FloChIP for the transcription factor MEF2A in 32 distinct human lymphoblastoid cell lines, providing insights into the main factors driving collaborative DNA binding of MEF2A and into its role in B cell-specific gene regulation. Together, our results validate FloChIP as a flexible and reproducible automated solution for individual or sequential ChIP-seq

Clocks do not tick in unison: isolation of Clock and vrille shed new light on the clockwork model of the sand fly Lutzomyia longipalpis

Submitted by sandra infurna ([email protected]) on 2016-03-10T11:54:08Z No. of bitstreams: 1 joao_gesto_etal_IOC_2015.pdf: 553724 bytes, checksum: b41592733dbfe464b0c6b7da57943612 (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-03-10T14:31:30Z (GMT) No. of bitstreams: 1 joao_gesto_etal_IOC_2015.pdf: 553724 bytes, checksum: b41592733dbfe464b0c6b7da57943612 (MD5)Made available in DSpace on 2016-03-10T14:31:30Z (GMT). No. of bitstreams: 1 joao_gesto_etal_IOC_2015.pdf: 553724 bytes, checksum: b41592733dbfe464b0c6b7da57943612 (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Epidemiologia e Sistemática Molecular. Rio de Janeiro, RJ, Brasil.École Polytechnique Fédérale de Lausanne. School of Life Sciences. , Institute of Bioengineering. Laboratory of Systems Biology and Genetics. Lausanne, Switzerland.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório Transmissores de Leishmanioses. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular. Rio de Janeiro, RJ, Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM)/ CNPq. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Molecular. Rio de Janeiro, RJ, Brasil / Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM)/ CNPq. Rio de Janeiro, RJ, Brasil.Background: Behavior rhythms of insect vectors directly interfere with the dynamics of pathogen transmission to humans. The sand fly Lutzomyia longipalpis is the main vector of visceral leishmaniasis in America and concentrates its activity around dusk. Despite the accumulation of behavioral data, very little is known about the molecular bases of the clock mechanism in this species. This study aims to characterize, within an evolutionary perspective, two important circadian clock genes, Clock and vrille. Findings: We have cloned and isolated the coding sequence of L. longipalpis’ genes Clock and vrille. The former is structured in eight exons and encodes a protein of 696 amino acids, and the latter comprises three exons and translates to a protein of 469 amino acids. When compared to other insects’ orthologues, L. longipalpis CLOCK shows a high degree of conservation in the functional domains bHLH and PAS, but a much shorter glutamine-rich (poly-Q) C-terminal region. As for L. longipalpis VRILLE, a high degree of conservation was found in the bZIP domain. To support these observations and provide an elegant view of the evolution of both genes in insects, phylogenetic analyses based on maximum-likelihood and Bayesian inferences were performed, corroborating the previously known insect systematics. Conclusions: The isolation and phylogenetic analyses of Clock and vrille orthologues in L. longipalpis bring novel and important data to characterize this species’ circadian clock. Interestingly, the poly-Q shortening observed in CLOCK suggests that its transcription activity might be impaired and we speculate if this effect could be compensated by other clock factors such as CYCLE

Anatomical terminology of the internal nose and paranasal sinuses: cross-cultural adaptation to Portuguese

Introduction: Functional endonasal endoscopic surgery is a frequent surgical procedure among otorhinolaryngologists. In 2014, the European Society of Rhinology published the “European Position Paper on the Anatomical Terminology of the Internal Nose and Paranasal Sinuses”, aiming to unify the terms in the English language. We do not yet have a unified terminology in the Portuguese language. Objective: Transcultural adaptation of the anatomical terms of the nose and paranasal cavities of the “European Anatomical Terminology of the Internal Nose and Paranasal Sinuses” to Portuguese. Methods: A group of rhinologists from diverse parts of Brazil, all experienced in endoscopic endonasal surgery, was invited to participate in the creation of this position paper on the anatomical terms of the nose and paranasal sinuses in the Portuguese language according to the methodology adapted from that previously described by Rudmik and Smith. Results: The results of this document were generated based on the agreement of the majority of the participants according to the most popular suggestions among the rhinologists. A cross-cultural adaptation of the sinonasal anatomical terminology was consolidated. We suggest the terms “inferior turbinate”, “nasal septum”, “(bone/cartilaginous) part of the nasal septum”, “(middle/inferior) nasal meatus”, “frontal sinus drainage pathway”, “frontal recess” and “uncinate process” be standardized. Conclusion: We have consolidated a Portuguese version of the European Anatomical Terminology of the Internal Nose and Paranasal Sinuses, which will help in the publication of technical announcements, scientific publications and the teaching of the internal anatomical terms of the nose and paranasal sinuses in Brazil. Resumo: Introdução: A cirurgia endoscópica funcional endonasal é um procedimento cirúrgico frequente entre os otorrinolaringologistas. Em 2014, a Sociedade Europeia de Rinologia publicou o “Documento Europeu para Posicionamento sobre a Terminologia Anatômica Interna do Nariz e das Cavidades Paranasais” com o objetivo de unificar os termos na língua inglesa. Ainda não dispomos de uma terminologia unificada na língua portuguesa. Objetivo: Adaptação transcultural dos termos anatômicos do nariz e das cavidades paranasais para o português da “European Anatomical Terminology of the Internal Nose and Paranasal Sinuses”. Método: Um grupo de rinologistas de todo o Brasil, com experiência em cirurgia endoscópica endonasal, foi convidado a participar da elaboração desse posicionamento sobre os termos anatômicos do nariz e das cavidades paranasais para o português conforme metodologia adaptada da previamente descrita por Rudmik e Smith. Resultados: Os resultados desse documento foram gerados a partir da concordância da maioria dos participantes conforme as sugestões mais populares entre os rinologistas. Uma adaptação transcultural da terminologia anatômica nasossinusal foi consolidada. Sugerimos que se busque uniformizar termos como “concha inferior”, “septo nasal”, “porção (óssea/cartilagionasa) do septo nasal”, “meato (médio/ inferior) nasal”, “via da drenagem do seio frontal”,“recesso frontal” e “processo uncinado”. Conclusão: Consolidamos uma versão adaptada em português da “European Anatomical Terminology of the Internal Nose and Paranasal Sinuses” que auxiliará a publicação de comunicados técnicos, publicações científicas e o ensino dos termos anatômicos internos do nariz e das cavidades paranasais no Brasil. Keywords: Cross-cultural adaptation, Anatomy, Nose, Paranasal sinus, Consensus, Palavras-chave: Adaptação transcultural, Anatomia, Nariz, Cavidades paranasais, Consens

Disturbances, elevation, topography and spatial proximity drive vegetation patterns along an altitudinal gradient of a top biodiversity hotspot

The correlation between vegetation patterns (species distribution and richness) and altitudinal variation has been widely reported for tropical forests, thereby providing theoretical basis for biodiversity conservation. However, this relationship may have been oversimplified, as many other factors may influence vegetation patterns, such as disturbances, topography and geographic distance. Considering these other factors, our primary question was: is there a vegetation pattern associated with substantial altitudinal variation (10-1,093 m a.s.l.) in the Atlantic Rainforest-a top hotspot for biodiversity conservation-and, if so, what are the main factors driving this pattern? We addressed this question by sampling 11 1-ha plots, applying multivariate methods, correlations and variance partitioning. The Restinga (forest on sandbanks along the coastal plains of Brazil) and a lowland area that was selectively logged 40 years ago were floristically isolated from the other plots. The maximum species richness (>200 spp. per hectare) occurred at approximately 350 m a.s.l. (submontane forest). Gaps, multiple stemmed trees, average elevation and the standard deviation of the slope significantly affected the vegetation pattern. Spatial proximity also influenced the vegetation pattern as a structuring environmental variable or via dispersal constraints. Our results clarify, for the first time, the key variables that drive species distribution and richness across a large altitudinal range within the Atlantic Rainforest. © 2013 Springer Science+Business Media Dordrecht

Circadian rhythms in insect disease vectors

Organisms from bacteria to humans have evolved under predictable daily environmental cycles owing to the Earth's rotation. This strong selection pressure has generated endogenous circadian clocks that regulate many aspects of behaviour, physiology and metabolism, anticipating and synchronising internal time-keeping to changes in the cyclical environment. In haematophagous insect vectors the circadian clock coordinates feeding activity, which is important for the dynamics of pathogen transmission. We have recently witnessed a substantial advance in molecular studies of circadian clocks in insect vector species that has consolidated behavioural data collected over many years, which provided insights into the regulation of the clock in the wild. Next generation sequencing technologies will facilitate the study of vector genomes/transcriptomes both among and within species and illuminate some of the species-specific patterns of adaptive circadian phenotypes that are observed in the field and in the laboratory. In this review we will explore these recent findings and attempt to identify potential areas for further investigation