974 resultados para molecular tests


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

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The aim of this work was to molecularly detect Leishmania species in 52 cats from Andradina Municipality, São Paulo State, Brazil. The direct parasitological test was performed by using imprints of poplited lymph node, bone marrow and spleen to verify amastigote forms of Leishmania spp. The samples that were positive parasitological tests were subjected to molecular analysis (PCR) and sequencing. Infection was detected for 5.76% (3/52) of the examined cats and two had presence of amastigote forms of Leishmania spp. in lymph nodes. Polymerase chain reaction (PCR) of kinetoplast minicircle DNA, indicated positive amplification for samples of spleen and lymph nodes and the sequencing resulted in 97% similarity with Leishmania (L) chagasi. This study proved the occurrence of infection with Leishmania (L) chagasi in felines from Andradina municipality, São Paulo State. (C) 2010 Elsevier B.V. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Poison frogs of the family Dendrobatidae contain cryptic as well as brightly colored, presumably aposematic species. The prevailing phylogenetic hypothesis assumes that the aposematic taxa form a monophyletic group while the cryptic species (Colostethus sensu lato) are basal and paraphyletic. Analysis of 86 dendrobatid sequences of a fragment of the 16S rRNA gene resulted in a much more complex scenario, with several clades that contained aposematic as well as cryptic taxa. Monophyly of the aposematic taxa was significantly rejected by SH-tests in an analysis with additional 12S and 16S rDNA fragments and reduced taxon sampling. The brightly colored Allobates femoralis and A. zaparo (Silverstone) comb. nov. (previously Epipedobates) belong in a clade with cryptic species of Colostethus. Additionally, Colostethus pratti was grouped with Epipedobates, and Colostethus bocagei with Cryptophyllobates. In several cases, the aposematic species have general distributions similar to those of their non-aposematic sister groups, indicating multiple instances of regional radiations in which some taxa independently acquired bright color. From a classificatory point of view, it is relevant that the type species of Minyobates, M. steyermarki, resulted as the sister group of the genus Dendrobates, and that species of Mannophryne and Nephelobates formed monophyletic clades, corroborating the validity of these genera. Leptodactylids of the genera Hylodes and Crossodactylus were not unambiguously identified as the sister group of the Dendrobatidae; these were monophyletic in all analyses and probably originated early in the radiation of Neotropical hyloid frogs.

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A hemoglobina fetal - Hb F, formada por duas cadeias gama e duas cadeias alfa, é característica do período fetal do desenvolvimento, tendo sua síntese diminuída no período pós-natal. em algumas alterações hereditárias, a Hb F permanece aumentada, como nas delta-beta talassemia, beta talassemia e persistência hereditária de Hb F (PHHF). A síntese da globina gama também pode ser estimulada por fatores externos como leucemias, transplantes de medula óssea, induções químicas, dentre outros. Através da observação de Hb F aumentada em doadores de sangue por procedimentos eletroforéticos objetivou-se avaliar a quantidade de Hb F em amostras de sangue de candidatos à doação, visando estabelecer seus limites de normalidade na população de São José do Rio Preto e região, por meio de desnaturação alcalina e cromatografia líquida de alta pressão (HPLC), comparar as metodologias aplicadas e, nos indivíduos com Hb F aumentada, realizar estudos moleculares para identificar as mutações que alteram a expressão dos genes gama. Foram analisadas 208 amostras de sangue, sendo 119 de candidatos à doação e 89 de indivíduos sem sintomas de anemia ou achados hematológicos e com Hb F aumentada como grupo comparativo. Das 119 amostras de candidatos à doação, 110 foram utilizadas para traçar o perfil de normalidade de Hb F, comparando-se as metodologias de desnaturação alcalina e HPLC, onde se obteve a média de 1,48% e de 0,6%, respectivamente. A análise estatística por regressão linear mostrou diferença significativa na comparação entre as duas metodologias aplicadas, sendo a HPLC mais precisa para a quantificação de Hb F. Foram observados nos testes de rastreamento de hemoglobinas anormais nestas 110 amostras de sangue: 16,4% de alfa talassemia, 0,9% com Hb F aumentada, 0,9% com beta talassemia e 0,9% com hemoglobina variante de cadeia delta. Os outros nove doadores de sangue apresentaram Hb F acima de 10% em eletroforese e observou-se média de 32,28% para desnaturação alcalina e de 26,4% para HPLC. As análises moleculares por PCR-ASO foram realizadas na tentativa de se identificar um defeito genético que pudesse explicar o aumento de Hb F, pelo rastreamento de 16 mutações que originam talassemias do tipo beta. Encontraram-se 5,3% de heterozigotos para mutação CD6-A e 1,75% para as mutações CD 39, IVS1:6, -87 e IVS2:654, todas em heterozigose. Os resultados encontrados neste estudo evidenciam a necessidade de melhor caracterização dos perfis de hemoglobina obtidos pelos métodos clássicos e a importância de sua caracterização molecular.

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Poucos estudos foram desenvolvidos no Brasil sobre a doença hérnia das crucíferas, causada por Plasmodiophora brassicae. Realizou-se testes de severidade da doença causada por diferentes populações do patógeno em espécies de brássicas (couve-flor, couve-chinesa suscetível, couve-chinesa resistente, brócolis e repolho). As populações de P. brassicae foram obtidas de raízes de brássicas infectadas originárias de algumas regiões produtoras no Brasil. Os testes de severidade foram realizados em casa de vegetação (25±2ºC) mediante inoculações, no colo de cada planta com 2 mL da suspensão de esporos do patógeno, na concentração de 107 esporos mL-1. As avaliações ocorreram 35 dias após a inoculação. em laboratório foi realizada a extração de DNA dessas populações e análises de PCR-RAPD para a comparação das características genéticas. As populações obtidas nas regiões de Carandaí MG e Colombo PR mostraram-se mais agressivas, manifestando patogenicidade até mesmo em cultivar considerada resistente. Entretanto, não foi observado um padrão genético específico quanto ao local de origem das populações avaliadas, sugerindo que mesmo em locais distantes e com diferenças quanto à severidade, tais populações são geneticamente semelhantes.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The common everyday use of medicinal plants is an ancient, and still very widespread practice, whereby the need for studies on their possible toxicity and mutagenic properties. The species Coccoloba mollis has been much used in phytotherapy, mainly in cases involving loss of memory and stress. In order to investigate its genotoxic and mutagenic potential, ethanolic extracts from the leaves and roots underwent Salmonella/microsome assaying (TA98 and TA100 strains, with and without exogenous metabolism - S9), besides comet and micronucleus tests in vivo.There was no significant increase in the number of revertants/plate of Salmonella strains in any of the analyzed root-extract concentrations, although the extract itself was extremely toxic to the Salmonella TA98 strain in the tests carried out with S9 (doses varying from 0.005 to 0.5 µg/plate). on the other hand, the leaf-extract induced mutations in the TA98 strain in the absence of S9 in the highest concentration evaluated, although at very low mutagenic potency (0.004 rev/µg). Furthermore, there was no statistically significant increase in the number of comets and micronuclei, in treatments involving Swiss mice. It was obvious that extracts of Coccoloba mollis, under the described experimental conditions, are not mutagenic.

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Hepatozoon canis is a protozoan that infects dogs and is transmitted by the ingestion of the brown dog tick, Rhipicephalus sanguineus. Two distinct species of Hepatozoon genus can infect dogs, H. canis and H. americanum. Routine tests to detect the disease are based on direct examination of gametocytes on Giemsa-stained blood smears. The objectives of this study were the investigation of infection prevalence in rural area dogs, the comparison of diagnostics by blood smear examination and polymerase chain reaction (PCR), and the association of infection with tick infestation. Blood smears, collected by puncture of the cephalic vein and ear margin capillary bed from 150 dogs, were examined. This technique detected 17 positive animals (11.3%), with 14 (9.3%) in peripheral blood and seven (4.7%) in cephalic vein blood. PCR tests detected 80 (53.3%) positive animals. R. sanguineus and Amblyomma spp. were found in 36 of the dogs (24%), in equal proportions. The identified species for Amblyomma genus were A. cajennense and A. ovale. Data analysis showed that PCR was much more sensitive when compared to blood smear examination. Hepatozoon species was previously identified as closely related to H. canis.

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Powdery mildew of rubber tree caused by Oidium heveae is an important disease of rubber plantations worldwide. Identification and classification of this fungus is still uncertain because there is no authoritative report of its morphology and no record of its teleomorphic stage. In this study, we compared five specimens of the rubber powdery mildew fungus collected in Malaysia, Thailand, and Brazil based on morphological and molecular characteristics. Morphological results showed that the fungus on rubber tree belongs to Oidium subgen. Pseudoidium. Nucleotide sequence analysis of the ribosomal DNA internal transcribed spacer (ITS) region and the large subunit rRNA gene (28S rDNA) were conducted to determine the relationships of the rubber powdery mildew fungus and to link this anamorphic fungus with its allied teleomorph. The results showed that the rDNA sequences of the two specimens from Malaysia were identical to a specimen from Thailand, whereas they differed by three bases from the two Brazilian isolates: one nucleotide position in the ITS2 and two positions in the 28S sequences. The ITS sequences of the two Brazilian isolates were identical to sequences of Erysiphe sp. on Quercus phillyraeoides collected in Japan, although the 28S sequences differed at one base from sequences of this fungus. Phylogenetic trees of both rDNA regions constructed by the distance and parsimony methods showed that the rubber powdery mildew fungus grouped with Erysiphe sp. on Q. phillyraeoides with 100% bootstrap support. Comparisons of the anamorph of two isolates of Erysiphe sp. from Q. phillyraeoides with the rubber mildew did not reveal any obvious differences between the two powdery mildew taxa, which suggests that O. heveae may be an anamorph of Erysiphe sp. on Q. phillyraeoides. Cross-inoculation tests are required to substantiate this conclusion. © The Mycological Society of Japan and Springer-Verlag 2005.

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Pós-graduação em Biotecnologia - IQ

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)