989 resultados para NESTED PCR ASSAY
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The presence of the very virulent (vv) Brazilian strain of infectious bursal disease virus (IBDV) was determined in the bursa of Fabricius, thymus and liver of 2-week-old broilers from a flock with a higher than expected mortality. For this purpose, a direct in situ reverse transcriptase (RT)-linked polymerase chain reaction (PCR) method was developed using specific primers for vvIBDV. Unlabelled forward and reverse biotinylated oligonucleotides were used for RT-PCR in a one-step method and the respective products were revealed by a direct enzymatic reaction. The results were compared with those obtained by standard RT-PCR using general primers for IBDV and virus isolation. The virus isolation, RT-PCR and in situ RT-PCR revealed positive results on the bursa of Fabricius in 86%, 80% and 100%, respectively. The in situ RT-PCR detected vvIBDV in all tested thymus and liver samples, whereas the standard RT-PCR detected virus in 80% and 90% of the samples, respectively. After three consecutive passages on chicken embryonated eggs, IBDV was isolated from 64% of the thymus samples and 30% of the liver samples. In the present study, no classical or antigenic variants of IBDV were detected. The developed in situ RT-PCR assay was able to detect the very virulent strain of IBDV with a higher sensitivity than the conventional RT-PCR and virus isolation.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of the present study was to evaluate different techniques for the detection of Paracoccidioides brasiliensis in soil, e.g., culture, animal inoculation and specific DNA amplification by Nested PCR. We designed species-specific inner primers derived from rDNA regions (ITS, 5.8S gene) and found their sensitivity to be higher than culture and animal inoculation. In addition, the sensitivity of these primers was higher than p27-gene primers developed for detection of P brasiliensis in soil in a previous study. DNA from P brasiliensis was detected in soil artificially seeded with the fungus (positive soil control) and from environmental samples collected in an armadillo burrow.
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Paracoccidioides brasiliensis infections have been little studied in wild and/or domestic animals, which may represent an important indicator of the presence of the pathogen in nature. Road-killed wild animals have been used for surveillance of vectors of zoonotic pathogens and may offer new opportunities for eco-epidemiological studies of paracoccidiodomycosis (PCM). The presence of P. brasiliensis infection was evaluated by Nested-PCR in tissue samples collected from 19 road-killed animals; 3 Cavia aperea (guinea pig), 5 Cerdocyon thous (crab-eating-fox), 1 Dasypus novemcinctus (nine-banded armadillo), 1 Dasypus septemcinctus (seven-banded armadillo), 2 Didelphis albiventris (white-eared opossum), 1 Eira barbara (tayra), 2 Gallictis vittata (grison), 2 Procyon cancrivorus (raccoon) and 2 Sphiggurus spinosus (porcupine). Specific P. brasiliensis amplicons were detected in (a) several organs of the two armadillos and one guinea pig, (b) the lung and liver of the porcupine, and (c) the lungs of raccoons and grisons. P. brasiliensis infection in wild animals from endemic areas might be more common than initially postulated. Molecular techniques can be used for detecting new hosts and mapping 'hot spot' areas of PCM.
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Hepatozoon canis was molecularly identified in Rio de Janeiro State, Brazil. Twelve dogs from urban areas were studied by blood smear examination and the polymerase chain reaction (PCR) assay. From these dogs, only 1 was positive in both blood smears and PCR.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A Nested-PCR (N-PCR) tem como objetivo melhorar a sensibilidade do diagnóstico direto da Pneumonia Enzoótica Suína, pois o isolamento do Mycoplasma hyopneumoniae é trabalhoso tornando-se inviável na rotina. Neste trabalho, foi realizado um projeto piloto para a otimização da técnica de N-PCR, utilizando três variáveis: tipo de amostra biológica, meio de transporte da amostra e método de extração do DNA, utilizando oito animais. Os resultados obtidos foram empregados no segundo experimento para a validação do teste utilizando 40 animais. Os resultados obtidos, pela otimização da N-PCR, neste trabalho, permite sugerir esta prova como método de diagnóstico de rotina no monitoramento das infecções por Mycoplasma hyopneumoniae em granjas de suínos.
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A total of 145 capybara (Hydrochoerus hydrochaeris) fecal samples from the state of Sdo Paulo, Brazil, were screened for Cryptosporidium spp. oocysts using the malachite green method. Eight samples (5.52%) showed positive results and were further submitted to nested PCR reaction for amplification of fragments of 18S rRNA gene and 60-kDa glycoprotein gene for determination of species, alleles and subtypes of Cryptosporidium. Sequencing of the PCR products of the 18S rRNA gene fragments and 60-kDa glycoprotein gene fragments showed that for both genes all Cryptosporidium isolates from capybara were respectively 100% genetically similar to a bovine isolate of C. parvum and to C parvum subtype IIaA15G2R1. To the best of our knowledge this is the first report of Cryptosporidium infection in this rodent. The finding of zoonotic C parvum infection in a semi-aquatic mammal that inhabits anthroponotic habitats raises the concern that human water supplies may be contaminated with zoonotic Cryptosporidium oocysts from wildlife. (c) 2007 Elsevier B.V. All rights reserved.
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Strains of Xylella fastidiosa, isolated from sweet orange trees (Citrus sinensis) and coffee trees (Coffea arabica) with symptoms of citrus variegated chlorosis and Requeima do Cafe, respectively, were indistinguish able based on repetitive extragenic palindromic polymerase chain reaction (PCR) and enterobacterial repetitive intergenic consensus PCR assays. These strains were also indistinguishable with a previously described PCR assay that distinguished the citrus strains from all other strains of Xylella fastidiosa. Because we were not able to document any genomic diversity in our collection of Xylella fastidiosa strains isolated from diseased citrus, the observed gradient of increasing disease severity from southern to northern regions of São Paulo State is unlikely due to the presence of significantly different strains of the pathogen in the different regions. When comparisons were made to reference strains of Xylella fastidiosa isolated from other hosts using these methods, four groups were consistently identified consistent with the hosts and regions from which the strains originated: citrus and coffee, grapevine and almond, mulberry, and elm, plum, and oak. Independent results from random amplified polymorphic DNA (RAPD) PCR assays were also consistent with these results; however, two of the primers tested in RAPD-PCR were able to distinguish the coffee and citrus strains. Sequence comparisons of a PCR product amplified from all strains of Xylella fastidiosa confirmed the presence of a CfoI polymorphism that can be used to distinguish the citrus strains from all others. The ability to distinguish Xylella fastidiosa strains from citrus and coffee with a PCR-based assay will be useful in epidemiological and etiological studies of this pathogen.