252 research outputs found

    Specific boundaries between the causal agents of the soybean stem canker

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    Pathogens within the Diaporthe complex cause seed decay, stem blight and stem canker on soybean, representing a serious threat for this crop species. We herein utilize worldwide sequence data retrieved from Genbank in order to assess the species boundaries between the soybean stem canker causal agents, and define whether or not they should be regarded as members of the same biological species. These studies were complemented with compatibility tests, in order to validate our findings from a biological standpoint. Species delimitation assays supported the occurrence of a speciation event between D. caulivora and D. phaseolourm var. meridionalis. A speciation hypothesis between D. aspalathi and D. phaseolourm var. meridionalis was also supported, based on three reciprocally monophyletic substitutions at locus EF1-α. Compatibility tests further validated species delimitation assays indicating that D. caulivora has developed barriers to gene exchange with D. phaseolorum var. meridionalis. Clarification of the specific boundaries of the SSC pathogens and related entities will be an important asset to future research in soybean pathology, epidemiology and breeding.Fil: Guillin, Eduardo A.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Grijalba, Pablo Enrique. Universidad de Buenos Aires. Facultad de Agronomia; ArgentinaFil: Oliveira, Luiz Orlando de. Universidade Federal de Viçosa; BrasilFil: Gottlieb, Alexandra Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

    Geração da nicotinamida adenina dinucleotídeo fosfato reduzida mediada pela glicose- 6-fosfato desidrogenase e 6-fosfogliconato desidrogenase em neutrófilos de cavalos Puro-Sangue Inglês.

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    Twenty adult thoroughbred horses wereinvestigated for neutrophil glucose-6-phosphatedehydrogenase and 6-phosphogluconate dehydrogenasespecific activities which were found to be 945 ± 288-1 -1 mlU mg of protein and 375 ± 88 mlU mg of proteinrespectively, per minute at 37 °C.Em vinte cavalos Puro-Sangue Inglês determinou-se a atividade da glicose-6-fosfatodesidrogenase e da 6-osfogliconato-desidrogenase de neutrófilos, encontrando-se atividades especificas de 945 ± 288 mUI mgˉ ¹ de proteína e 375 ± 88 mUI mgˉ ¹ de proteína, respectivamente, por minuto a 37 °C

    Enzimas eritrocitárias dependentes das vitaminas B2 e B6, em cavalos recém-nascidos e adultos Puro-Sangue Inglês

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    In order to assess the Thoroughbred horses nutritional status as to riboflavin and pyridoxine, 10 adults and 30 newborns were investigated. In both adults and newborns, riboflavin intake was sufficient to meet their nutritionalneeds; however, a moderate pyridoxine deficiency was detected amongst the adult horses, but not in the newborns. This findings suggests that a pyridoxine supplementation to adult horses may be necessary to keep their nutritional poise.Com o propósito de determinar o estado nutricional de cavalos Puro-Sangue Inglês (PSI) em relação à riboflavina (vitamina B2) e à piridoxina (vitamina B6), 10 animais adultos e 30 recém-nascidos foram investigados. Foi observado um bom estado nutricional quanto à riboflavina, notando-se moderada deficiência de piridoxina nos animais adultos, mas não nos recém-nascidos. Estes fatos sugerem que os animais adultos devam receber suplementação com piridoxina

    Guia de identificação dos ninhos de vespas sociais (Hymenoptera, Vespidae, Polistinae) na Reserva Ducke, Manaus, Amazonas, Brasil

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    Identification guide for nests of social wasps (Hymenoptera: Vespidae: Polistinae) in Reserva Ducke, Manaus, Amazonas, Brazil. Nests of social wasps are composed mainly out of plant material. Although there are some studies about the social wasp fauna in the Amazon region, there is no work exclusively about these wasps' nests. Also, there are few catalogued nests in biological collections, because of their fragility and difficult conservation. The purpose of this study was to evaluate the kinds of nests found at "Reserva Ducke", compiling information about them and developing a key to identify the nests of each genera. The nests were actively collected in tracks of the "Programa de Pesquisa em Biodiversidade" plot; areas such as "igarapés" margins, base camp's surroundings and buildings at the reserve headquarters were also explored. All the nests were photographed and their precise location was obtained by GPS. Thirty-nine wasp's nests from 17 species of Polistinae were recorded: Agelaia constructor, A. pallipes, Angiopolybia pallens, Apoica pallens, Metapolybia unilineata, Mischocyttarus lecointei, M. saturatus, Polybia bistriata, P. dimidiata, P. jurinei, P. liliacea, P. occidentalis, P. procellosa, P. rejecta, Protopolybia bituberculata, P. chartergoides and Synoeca virginea. Five uninhabited nests of Mischocyttarus, Polybia and Polistes were collected

    Evaluation of Selective Physicochemical and Biological Properties of Different Root Canal Sealers

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    Introduction: This in vitro study aimed to evaluate the chemical composition, water solubility, radiopacity, pH, electrical conductivity and cytotoxicity of four different root canal sealers. Methods and Materials: Four materials were tested including an epoxy resin-based sealer (AH-Plus), a calcium silicate-based sealer (MTA Fillapex), a calcium hydroxide-based sealer (Sealapex) and a zinc-oxide-eugenol-based sealer (Endofill). The materials were submitted to energy-dispersive x-ray microanalysis for elemental chemical composition. Solubility and radiopacity were evaluated according to ANSI/ADA. The pH and electrical conductivity were measured at different periods of time. L929 immortalized mouse fibroblast line were used for cytotoxicity evaluation. Statistical analyses were carried out using the ANOVA and Tukey’s test. Results: The main elements were found to be silicon and calcium in MTA Fillapex, calcium and bismuth in Sealapex, zirconium and tungsten in AH-Plus and zinc and bismuth in Endofill. Sealapex had the highest value for solubility (P<0.05), AH-Plus showed the highest radiopacity value (P<0.05) while MTA Fillapex had the highest pH and electrical conductivity values (P<0.05). AH-Plus showed the highest rate of cell viability (P<0.05). Conclusion: Based on the results of this in vitro study, it was possible to conclude that Endofill and Sealpex did not meet the requirements for water solubility. The tested sealers were alkaline and showed radiopacity in accordance with ANSI/ADA standards. AH-Plus showed to be less cytotoxic than other tested root canal sealers. Keywords: Biological Assay; Endodontics; Root Canal Filling Materials; Root Canal Obturatio

    Diversidade genética estimada com marcadores ISSR em populações brasileiras de Zabrotes subfasciatus

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    The objective of this work was to evaluate the genetic diversity of populations of Zabrotes subfasciatus through ISSR molecular markers. Twelve populations from eight Brazilian states were sampled in the total of 269 individuals. Five ISSR primers were used and a total of 51 polymorphic bands were obtained. The percentage of polymorphism within population averaged 83.8%. Nei's unbiased expected heterozygosity ranged from 0.23 to 0.33, with an average of 0.29, and the Shannon & Weaver's index of gene diversity varied from 0.29 to 0.48, with an average of 0.42. At species level, these two indexes were 0.36 and 0.54, respectively. The analysis of molecular variance showed that 66% of the total molecular variance can be attributed to differences within population, while 34% was apportioned among populations. Mantel's test showed a low correlation between: geographic distance and genetic differentiation, genetic identity and genetic differentiation, and Nei's genetic distance and genetic differentiation. The genetic differentiation in Brazilian populations of Z. subfasciatus is low and geographic structuring is weak.O objetivo deste trabalho foi estimar a diversidade genética de populações de Zabrotes subfasciatus, por meio de marcadores moleculares ISSR. Foram avaliadas 12 populações, provenientes de oito estados brasileiros, no total de 269 indivíduos. Cinco iniciadores ISSR permitiram a obtenção do total de 51 fragmentos polimórficos. A percentagem média de locos polimórficos, dentro de cada população, foi de 83,8%. A heterozigosidade corrigida de Nei esperada variou de 0,23 a 0,33, com média de 0,29, e o índice de diversidade genética de Shannon e Weaver variou de 0,29 a 0,48, com média de 0,42. No nível de espécie, estes dois índices apresentaram valores de 0,36 e 0,54, respectivamente. A análise de variância molecular mostrou que 66% da variância molecular total pode ser atribuída a diferenças intrapopulacionais e que os 34% restantes podem ser atribuídos a diferenças interpopulacionais. O teste de Mantel mostrou baixa correlação entre: distância geográfica e diferenciação genética, identidade genética e diferenciação genética e, distância genética de Nei e diferenciação genética. As populações brasileiras de Z. subfasciatus possuem baixa diferenciação genética e fraca estruturação geográfica

    DESEMPENHO DE ARGAMASSAS DE CIMENTO PORTLAND CONTENDO NANOTUBOS DE CARBONO E ADITIVO DE MELAMINA

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    Desde o seu descobrimento em 1991, os nanotubos de carbono (NTC) têm promovido grandes mudanças na área da engenharia de materiais. No caso específico de matrizes de cimento Portland, esses elementos de escala nanoscópica podem melhorar o desempenho das mesmas. Neste cenário, o objetivo deste trabalho foi avaliar o comportamento de argamassas fabricadas com cimento Portland CP V-ARI, adição física de NTC e aditivo à base de melaminaformaldeído. Para isso, foram utilizados nanotubos de carbono de paredes múltiplas e funcionalizados, em teores de 0,30% e 0,50% em relação ao peso do cimento. O comportamento de matrizes sem a presença de NTC também foi analisado para comparação. A resistência à compressão e resistência à tração por compressão diametral foram os ensaios realizados para a avaliação das propriedades mecânicas. A microscopia eletrônica de varredura (MEV) e o ensaio de área superficial específica (BET) foram utilizados na análise da microestrutura das matrizes. A análise dos resultados retratou um melhor comportamento das argamassas fabricadas com o teor de 0,30% de nanotubos de carbono
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