RESUMO
Triatomines have been important model organisms for behavioural research. Diverse reports about triatomine host search, pheromone communication in the sexual, shelter and alarm contexts, daily cycles of activity, refuge choice and behavioural plasticity have been published in the last two decades. In recent times, a variety of molecular genetics techniques has allowed researchers to investigate elaborate and complex questions about the genetic bases of the physiology of insects. This, together with the current characterisation of the genome sequence of Rhodnius prolixus allows the resurgence of this excellent insect physiology model in the omics era. In the present revision, we suggest that studying the molecular basis of behaviour and sensory ecology in triatomines will promote a deeper understanding of fundamental aspects of insect and, particularly, vector biology. This will allow uncovering unknown features of essential insect physiology questions for a hemimetabolous model organism, promoting more robust comparative studies of insect sensory function and cognition.
Assuntos
Animais , Comportamento Animal/fisiologia , Genoma de Inseto/genética , Insetos Vetores/genética , Triatominae/genética , Relógios Circadianos/genética , Ritmo Circadiano/genética , Locomoção , Feromônios/genética , Rhodnius/genética , Navegação EspacialRESUMO
Lutzomyia longipalpis s.l. is the main vector of American visceral leishmaniasis (AVL) and occurs as a species complex. DNA samples from two Brazilian sympatric species that differ in pheromone and courtship song production were used to analyse molecular polymorphisms in an odorant-binding protein ( obp29 ) gene. OBPs are proteins related to olfaction and are involved in activities fundamental to survival, such as foraging, mating and choice of oviposition site. In this study, the marker obp29 was found to be highly polymorphic in Lu. longipalpis s.l. , with no fixed differences observed between the two species. A pairwise fixation index test indicated a moderate level of genetic differentiation between the samples analysed.
Assuntos
Animais , Insetos Vetores/genética , Psychodidae/genética , Receptores Odorantes/genética , Comportamento Sexual Animal/fisiologia , Simpatria/genética , Brasil , Aptidão Genética , Feromônios/genética , Polimorfismo Genético/genética , Isolamento Reprodutivo , Análise de Sequência de DNARESUMO
No genoma de camundongo existem por volta de 1000 genes que codificam para receptores olfatórios (ORs) e 150 genes que codificam para receptores de feromônios do tipo 1 (V1Rs) distribuídos em vários cromossomos. Cada neurônio olfatório e vomeronasal seleciona um único alelo de um único gene de receptor OR ou de V1R, respectivamente, para expressar enquanto que o restante do repertório é mantido silenciado. Os mecanismos que regulam esse padrão de expressão não são conhecidos. As similaridades no padrão de expressão dos genes de ORs e de V1Rs sugerem que o mecanismo de regulação possa ser comum. Até então poucas regiões promotoras de genes de ORs e de genes de V1Rs haviam sido experimentalmente determinadas e pesquisadas. Realizamos uma análise na qual regiões a montante de um grande número de diferentes genes de ORs e de genes de V1Rs foram comparadas...
Assuntos
Animais , Camundongos , Expressão Gênica/genética , Feromônios/genética , Técnicas In Vitro , Biologia Molecular , Neurônios Receptores Olfatórios , Olfato/genética , Olfato/imunologia , Órgão Vomeronasal/imunologia , Receptores Odorantes/análise , Receptores Odorantes/biossíntese , Dissecação , Eletroforese , Espectrofotometria , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da PolimeraseRESUMO
Gene regulatory networks, or simply gene networks (GNs), have shown to be a promising approach that the bioinformatics community has been developing for studying regulatory mechanisms in biological systems. GNs are built from the genome-wide high-throughput gene expression data that are often available from DNA microarray experiments. Conceptually, GNs are (un)directed graphs, where the nodes correspond to the genes and a link between a pair of genes denotes a regulatory interaction that occurs at transcriptional level. In the present study, we had two objectives: 1) to develop a framework for GN reconstruction based on a Bayesian network model that captures direct interactions between genes through nonparametric regression with B-splines, and 2) to demonstrate the potential of GNs in the analysis of expression data of a real biological system, the yeast pheromone response pathway. Our framework also included a number of search schemes to learn the network. We present an intuitive notion of GN theory as well as the detailed mathematical foundations of the model. A comprehensive analysis of the consistency of the model when tested with biological data was done through the analysis of the GNs inferred for the yeast pheromone pathway. Our results agree fairly well with what was expected based on the literature, and we developed some hypotheses about this system. Using this analysis, we intended to provide a guide on how GNs can be effectively used to study transcriptional regulation. We also discussed the limitations of GNs and the future direction of network analysis for genomic data. The software is available upon request.
Assuntos
Humanos , Feromônios/genética , Regulação da Expressão Gênica/genética , Saccharomyces cerevisiae/química , Transcrição Gênica/genética , Transdução de Sinais/genética , Estatísticas não Paramétricas , Feromônios/metabolismo , Modelos Genéticos , Perfilação da Expressão Gênica/métodos , Teorema de BayesRESUMO
We developed a new approach for the reconstruction of phylogenetic trees using ant colony optimization metaheuristics. A tree is constructed using a fully connected graph and the problem is approached similarly to the well-known traveling salesman problem. This methodology was used to develop an algorithm for constructing a phylogenetic tree using a pheromone matrix. Two data sets were tested with the algorithm: complete mitochondrial genomes from mammals and DNA sequences of the p53 gene from several eutherians. This new methodology was found to be superior to other well-known softwares, at least for this data set. These results are very promising and suggest more efforts for further developments.
Assuntos
Humanos , Animais , Algoritmos , Evolução Molecular , Filogenia , Simulação por Computador , DNA Mitocondrial/genética , Feromônios/genética , Formigas/genética , /genética , MamíferosRESUMO
Acylsugars present in Lycopersicon pennellii are responsible for the high levels of pest resistance often found in this wild tomato taxon. We investigated the inheritance of acylsugar contents in segregating populations of the interspecific tomato cross L. esculentum x L. pennellii and estimated correlations between leaflet acylsugar contents and the levels of mite repellence. Acylsugar contents were quantified with the Sommogy-Nelson colorimetric method in the acessions L. esculentum 'TOM-584' (P(1), low acylsugars), L. pennellii 'LA-716' (P(2), high acylsugars), in the interspecific F(1) (P(1) x P(2)) and in the F(2 )(P(1) x P(2)) generations. Mite resistance was assessed by a repellence test. Broad-sense heritability of acylsugar contents was moderately high (h(2)(b) = 0.476). Frequency distributions in the P(1), P(2), F(1) and F(2) can be explained by the action of a single major locus, with near-complete dominance of the L. esculentum allele for low-acylsugar content over the L. pennellii allele for high content. Indirect selection for high levels of acylsugars in leaflets led to correlated increases in the levels of mite repellency, indicating that acylsugars may be the main factor involved in mite resistance