194 resultados para Megaselia scalaris


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We describe a case of myiasis in Crotalus durissus terrificus (Laurenti) caused by Megaselia scalaris (Loew). The snake was Found in Anhembi, São Paulo, Brazil, with a lesion measuring 25 mm in diameter where the larvae of M. scalaris had penetrated the ribs. The opportunistic behavior of the larvae of M. scalaris is discussed.

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A técnica de marcação de insetos de Tadei & Mourão (1976) é, até o momento, o único método experimental que possibilita determinar a idade real de cada indivíduo na população e, conseqüentemente, determinar a estrutura etária da mesma. Para isto propomos um aprimoramento dessa técnica, utilizada aqui para determinar a estrutura etária de populações da linhagem geográfica SR do díptero forídeo Megaselia scalaris Loew, mantidas pela técnica da transferência seriada em câmaras com temperatura constante de 25 ± 1,0ºC e 20 ± 1,0ºC. O estabelecimento da estrutura etária permitiu calcular a longevidade real das moscas e detectar o efeito ambiental temperatura, sendo fator determinante neste trabalho a marcação dos insetos, pois se não o fosse, teríamos somente estimativas e, dependendo do erro cometido na estimação, o efeito do fator de interesse (temperatura) poderia não ser detectado.

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A partir de perfis populacionais experimentais de linhagens do díptero forídeo Megaselia scalaris, foi determinado o número mínimo de perfis amostrais que devem ser repetidos, via processo de simulação bootstrap, para se ter uma estimativa confiável do perfil médio populacional e apresentar estimativas do erro-padrão como medida da precisão das simulações realizadas. Os dados originais são provenientes de populações experimentais fundadas com as linhagens SR e R4, com três réplicas cada, e que foram mantidas por 33 semanas pela técnica da transferência seriada em câmara de temperatura constante (25 ± 1,0ºC). A variável usada foi tamanho populacional e o modelo adotado para cada perfíl foi o de um processo estocástico estacionário. Por meio das simulações, os perfis de três populações experimentais foram amplificados, determinando-se, dessa forma, o tamanho mínimo de amostra. Fixado o tamanho de amostra, simulações bootstrap foram realizadas para construção de intervalos de confiança e comparação dos perfis médios populacionais das duas linhagens. Os resultados mostram que com o tamanho de amostra igual a 50 inicia-se o processo de estabilização dos valores médios.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Immunofluorescence has identified seven monoclonal antibodies reactive with the surface of meiotic cells and absent in premeiotic cells. Analysis by immunogold electron microscopy indicated that these antigens were present on the external surface of the cells and were coincident with the presence of synaptonemal complexes in the nucleus. On immunoblots a common glycosylated protein of 205 kDa was recognized, in addition to smaller subunits, suggesting the presence of a protein complex comprised of smaller peptides.

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Monoclonal antibodies have been prepared against purified pachytene cells from grasshopper testes. Immunoblotting and immunofluorescence analyses identified those monoclonal antibodies which showed specificity for antigens in pachytene cells. Several antigenic changes were found to be associated with meiotic cells. Five monoclonal antibodies detected antigens which were located in the cytoplasm of premeiotic cells but were nuclear during meiosis. One monoclonal antibody showed a discrete cytoplasmic fluorescent pattern in meiotic, but not in premeiotic, cells. Another bound specifically to the nuclei of some epithelial cells at the base of follicles in mature testes.

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The abalone Haliotis laevigata Donovan is commercially exploited in southern Australia; Haliotis scalaris Leach is a smaller, noncommercial species. This thesis describes the early life history of both species and other aspects of the fishery biology of H. Iaevigata required for fishery management. Both abalone species recruit onto a crustose coralline substratum variously from spring to winter. After settlement the growth rate of both species Is linear for a number of years (1 .7mm/month for H. Iaevigata and 1.1mm/month for H. scalaris) . Crustose coralline algae are the main food during the first year of life but thereafter the diet switches largely to drift algae and seagrass. Survival of newly-settled cohorts differed between years and between species. Overall, it appeared to be density Independent at low densities but density-dependent at high densities, Recruitment strength (measured at 2-1/2 - 3 years of age) and natural mortality of adults in a closed population was measured over 17 years at West I. There were sequences of strong and weak recruitments, but no relationship with presumed spawning stock size was apparent. Adult natural mortality rates ranged from 0.02 to 0.86 and were strongly density dependent. Stingrays were a major, and octopuses a minor, cause of mortality. The fecundity of H. Iaevigata was investigated at a number of sites and was adequately described by linear regressions of fecundity on total weight. Fecundity ratios and growth rate differed between sites and fecundity appears subject to phenotyplc and genotypic variation. The short and long term movement of H. laevigata was also examined, !n short term studies sexually mature Individuals aggregate during the spawning season but disperse randomly at other times of the year. In the longer term the amount of movement depends on availability of crevice space and size. Movement is also directional and, at one site, was toward that of the approaching swell. A method is described for estimating density of abalone by using a free-range search technique and adjusting for individual variation in power and efficiency of different divers and in differing degrees of habitat heterogeneity. The method is useful for estimating recruitment strength and density of abalone in surveys of abalone stocks.

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The Drosophila gene bicoid functions at the beginning of a gene cascade that specifies anterior structures in the embryo. Its transcripts are localized at the anterior pole of the oocyte, giving rise to a Bicoid protein gradient, which regulates the spatially restricted expression of target genes along the anterior–posterior axis of the embryo in a concentration-dependent manner. The morphogen function of Bicoid requires the coactivity of the zinc finger transcription factor Hunchback, which is expressed in a Bicoid-dependent fashion in the anterior half of the embryo. Whereas hunchback is conserved throughout insects, bicoid homologs are known only from cyclorrhaphan flies. Thus far, identification of hunchback and bicoid homologs rests only on sequence comparison. In this study, we used double-stranded RNA interference (RNAi) to address the function of bicoid and hunchback homologs in embryos of the lower cyclorrhaphan fly Megaselia abdita (Phoridae). Megaselia-hunchback RNAi causes hunchback-like phenotypes as observed in Drosophila, but Megaselia-bicoid RNAi causes phenotypes different from corresponding RNAi experiments in Drosophila and bicoid mutant embryos. Megaselia-bicoid is required not only for the head and thorax but also for the development of four abdominal segments. This difference between Megaselia and Drosophila suggests that the range of functional bicoid activity has been reduced in higher flies.

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本研究中运用四种不用的方法提取海带孢子体RNA,通过对比分析,确定了采用CTAB提取液[2% (w/v) CTAB,100 mM Tris-HC1 (pH 8.0), 50 mM EDTA, pH 7.5, 2 M NaCl, 50 mM DTT]提取RNA的方法,该方法的主要改进之处: (1) 高浓度(50 mM)的 DTT作为防止多酚氧化的还原剂加入提取液中;(2) 1/4 体积的乙醇和 1/9 体积的3 M 醋酸钾(pH 4.8)用来沉淀去除多糖;(3) 1/10倍体积的3 mol/L醋酸钠(pH 5.0)和两倍体积的乙醇选择性沉淀RNA;(4) -80℃沉淀30 min沉淀RNA。CTAB改进法提取的海带孢子体RNA质量好(A260/280 =1.96±0.05),产量高(68 μg/g),分离的RNA可用于RT-PCR反应,扩增相关基因片段。该方法提取海带配子体RNA效果也很好。 根据拟南芥(Arabidopsis thaliana)、 莱茵衣藻(Chlamydomonas reinhardtii) 、铁线蕨(Adiantum capillus-veneris)、转板藻(Mougeotia scalaris)和无隔藻(Vaucheria frigida)等的蓝光受体蛋白保守序列,设计一系列简并引物,进行RT-PCR扩增,筛选并克隆测序了4条序列片段,通过比对分析,所得序列与已知的蓝光受体基因序列不一致。在所获得的序列中,一条783 bp的序列与肌醇-1-磷酸合成酶基因的片段有较高的相似性,通过RACE法克隆出该基因的3’末端,5’末端克隆没有成功,全长序列有待深入分析。

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Solitary and presocial aculueate Hymenoptera are parasitized by a range of dipteran species in the families Axithomyiidae, Bombyliidae, Conopidae, Phoridae, and Sarcophagidae that are likely to impact on their hosts. We undertook a study over several years of a univoltine and communal bee, Andrena agilissima, and its main dipteran parasites, in particular the satellite fly Leucophora personata (Diptera: Anthomyiidae). Behavioural and ecological data were collected from one nesting aggregation of the host bee on the island of Elba, Italy, from 1993 to 2003, and from a foraging site of the bee, ca 5 km from the nesting aggregation. Other Diptera associated with A. agilissmia at the field site were the bee fly Bombylius fimbriatus (Bombyliidae), the conopid fly Zodion cinereum (Conopidae), and the scuttle fly Megaselia andrenae (Phoridae). The phenology of the Diptera broadly overlapped with that of their host across the season of activity (end of April and all of May). Diurnal activity patterns differed slightly; L. personata in particular was active at the host's nesting site before A. agilissima. Female satellite flies also showed a range of behaviours in gaining entry to a host nest. We summarize published data on this and other Leucophora species that parasitize Andrena host bees. Host bees returning to their nests occasionally undertook zig-zag flight manoeuvres if followed by a satellite fly that were generally successful in evading the fly. Satellite flies that entered a nest, presumably to oviposit, were less likely to remain therein if another host bee entered the same nest, suggesting that one advantage to communal nesting for this host is a reduction in brood cell parasitism by L. personata. We provide the first clear evidence for parasitism by a Zodion of any Andrena host. Both L. personata and M. andrenae concentrated their parasitic activities in the zone of the host nesting aggregation with highest nest densities. Three of the Diptera, L. personata, B. fimbriatus, and Z. cinereum, seemed to have extremely low rates of parasitism whilst that of M. andrenae appeared low. Though they have refined parasitic behaviour that allows them to gain entry into host nests (L. personata, B. fimbriatus, and M. andrenae) or to parasitize adults (Z. cinercum), these parasites seem not to impact upon the dynamics of the host A. agilissima at the nesting aggregation, and the host possesses traits to reduce parasitism.

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The speciose Brazilian Elateridae fauna is characterized by high karyotypic diversity, including one species (Chalcolepidius zonatus Eschscholtz, 1829) with the lowest diploid number within any Coleoptera order. Cytogenetic analysis of Conoderus dimidiatus Germar, 1839, C. scalaris (Germar, 1824,) C. ternarius Germar, 1839, and C. stigmosus Germar, 1839 by standard and differential staining was performed with the aim of establishing mechanisms of karyotypic differentiation in these species. Conoderus dimidiatus, C. scalaris, and C. ternarius have diploid numbers of 2n(male) = 17 and 2n(female) = 18, and a X0/XX sex determination system, similar to that encountered in the majority of Conoderini species. The karyotype of C. stigmosus was characterized by a diploid number of 2n=16 and a neoXY/neoXX sex determination system that was highly differentiated from other species of the genus. Some features of the mitotic and meiotic chromosomes suggest an autosome/ancestral X chromosome fusion as the cause of the neoXY system origin in C. stigmosus. C-banding and silver impregnation techniques showed that the four Conoderus species possess similar chromosomal characteristics to those registered in most Polyphaga species, including pericentromeric C band and autosomal NORs. Triple staining techniques including CMA(3)/DA/DAPI also provided useful information for differentiating these Conoderus species. These techniques revealed unique GC-rich heterochromatin associated with NORs in C. scalaris and C. stigmosus and CMA(3)-heteromorphism in C. scalaris and C. ternarius.

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The main characteristics of 55 nests of Protopolybia exigua exigua were periodically evaluated in Ribeirão Preto, southeastern Brazil. Although the queens' life-span can eventually reach one year, nests barely thrive for six months because most of them are periodically invaded by the scavenger phorid fly, Megaselia aff. picta. Under heavy infestation the adult wasp population partially closes the nest entrance, migrates and constructs a new nest in the neighborhood. Afterwards the old-nest's entrance can be completely closed by the wasps which results in blocking the parasitoid flies inside. In the tropics, predation by ants is considered the main selective pressure which shaped most of the bionomic characteristics of Polistinae wasps. It is suggested that Megaselia can easily overcome the usual wasps defensive tactics just because they are so specialized against ants. Aerial raids, fast erratic-jerking movements, rapid and efficient oviposition behavior, etc. can eventually turn Megaselia into a very important enemy of some social wasps.

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A busca por padrões de estrutura e composição das comunidades é essencial para prover informações que permitam o manejo sustentado de populações e monitoramento de atividades antrópicas. Na região neotropical, onde ocorre grande riqueza de espécies e complexas relações ecológicas entre elas, estudos envolvendo ofidiofauna ainda são escassos, o que faz com que o entendimento dos processos responsáveis pela estruturação de suas comunidades ainda seja incipiente. No Brasil, vários trabalhos foram desenvolvidos na tentativa de explicitar os fenômenos responsáveis pelos padrões de ocorrência e interações das espécies de serpentes. Objetivando esclarecer quais os fatores que determinam os padrões observados e que afinidades (ecológicas e/ou históricas) as espécies compartilham, foi realizado estudo da taxocenose de serpentes da FLONA de Caxiuanã e áreas adjacentes, durante os anos de 2005 e 2006. Utilizou-se conjuntamente quatro métodos de amostragem (Procura Limitada por Tempo-PLT, Encontros Ocasionais-EO, Armadilhas de Interceptação e Queda-AIQ e Coletas por Terceiros-CT), em cinco áreas (IBAMA e Caquajó, no interior da FLONA de Caxiuanã; Enseada e dois pontos com influência antrópica: Marinaú e Mojuá, estando esses três últimos localizados em áreas adjacentes à FLONA. Foram registrados 378 espécimes distribuídos em cinco famílias, 35 gêneros e 50 espécies. Com os novos registros obtidos nesse estudo, o número de espécies de serpentes para a FLONA de Caxiuanã e áreas adjacentes passa de 63 para 69. Os métodos que apresentaram melhor desempenho em número de indivíduos foram PLT (199/378) e CT (159/378). EO (11/378) e AIQ (9/378) foram os métodos menos eficazes. A riqueza estimada (Jackknife 1), a partir de dados obtidos através de PLT, foi de 56 (+ ou – 4) espécies. O número de espécies estimado para as áreas preservadas foi maior que para áreas antropizadas. A composição das espécies de serpentes da área estudada apresentou maior similaridade com outras taxocenoses de áreas amazônicas. As espécies mais abundantes, acessadas através de PLT, foram Imantodes cenchoa, Corallus hortulanus e Leptodeira annulata. Quando todos os métodos foram considerados, Bothrops atrox, Imantodes cenchoa e Corallus hortulanus foram as espécies mais representadas. As áreas mais antropizadas, localizadas fora da FLONA (Marinaú e Mojuá), apresentaram menores abundância e riqueza de espécies em comparação com áreas protegidas, localizadas no interior da FLONA. Nove espécies foram consideradas potencialmente especialistas: Lachesis muta (pequenos mamíferos), Atractus schach (minhocas), Dipsas catesbyi (moluscos - lesmas), Helicops trivitatus e Hydrops triangularis (peixes), Siphlophis compressus (lagartos), Xenopholis scalaris, Taeniophallus brevirostris (anfíbios anuros) e Tantilla melanocephala (centopéias). Os itens mais acessados foram “lagartos”, “anfíbios anuros” e “pequenos mamíferos”. Serpentes com hábitos primária ou exclusivamente diurnas prevaleceram na comunidade analisada. A ausência de sazonalidade reprodutiva foi característica da maioria das espécies e isso se deve, muito provavelmente, à pouca diferença na temperatura ao longo do ano. A taxocenose de serpentes da FLONA de Caxiuanã e áreas adjacentes está, basicamente, formada por grupos contendo espécies onde, em geral, hábitos diários e de dieta estão sobrepostos. Além dos diversos fatores ecológicos, também fatores históricos, como adaptações morfológicas das espécies, têm grande influência na composição da taxocenose analisada. A grande dificuldade na realização de estudos de comunidades de serpentes está na escassez de dados das espécies, portanto torna-se imperioso que estudos de Ecologia e História Natural continuem sendo exaustivamente conduzidos em uma mesma localidade, objetivando a elucidação dos padrões de respostas aos diversos fatores relacionados à existência das espécies nos diferentes biomas.