ABSTRACT Paper-based devices present low-cost and are versatile, making them very attractive for clinical analysis. To manufacture those devices wax patterns are printed on paper surface and upon heating the wax permeates through the entire thickness of the paper, creating hydrophobic barriers that delimit test areas. Antibodies produced in rabbits against canine distemper virus (CDV) were physically adsorbed on the surface of gold nanoparticles (AuNPs) and incubated with CDV viral antigens, forming the immunocomplex. Anti-CDV antibodies were immobilized into the microchannels by physical adsorption, forming the test region. The test solution containing conjugated AuNPs was applied at the bottom of the microchannel and it was eluted with a phosphate buffer solution 0.01 M pH 7.4. When the solution containing the AuNPs reached the test zone the recognition of antigens contained on the immunocomplex occurred with the consequent development of a red line, which represents a positive outcome for the test. This method demonstrated the success of physical immobilization of antibodies on AuNPs and the physical immobilization of antibodies on cellulose’s surface. This colorimetric assay brings simplicity and versatility to clinical analyses, presenting potential for CDV diagnosis.

The aim of this work was to evaluate two paternity cases by microchip electrophoresis and the validation of the methodology by comparison of the results with those obtained in a commercial genetic analyzer. It was observed that when working with tetranucleotide regions, in which the minimal difference between the alleles was only four base pairs, the commercial microchip system did not present the resolution and repeatability needed. Nevertheless, the relative standard deviation was between 0 and 1.2% and the fragments detected were within the expected size ranges as described in the literature.

DNA Microarray foi desenvolvida para monitorar a expressão de muitos genes de Xylella fastidiosa, permitindo a comparação de duas situações distintas em um único experimento. Os experimentos foram feitos utilizando células de X. fastidiosa cultivada em dois meios de cultura: BCYE e XDM2. Pares de oligonucleotídeos iniciadores foram sintetizados, depositados em lâminas de vidro e o arranjo foi hibridizado contra cDNAs marcados fluorescentemente. Os sinais emitidos foram quantificados, normalizados e os dados foram estatisticamente analisados para verificar os genes diferencialmente expressos. De acordo com nossos dados, 104 genes foram diferencialmente expressos para o meio de cultura XDM2 e 30 genes para o BCYE. No presente estudo, nós demonstramos que a técnica de DNA microarrays eficientemente diferencia genes expressos sob diferentes condições de cultivo.

DNA Microarray was developed to monitor the expression of many genes from Xylella fastidiosa, allowing the side by-side comparison of two situations in a single experiment. The experiments were performed using X. fastidiosa cells grown in two culture media: BCYE and XDM2. The primers were synthesized, spotted onto glass slides and the array was hybridized against fluorescently labeled cDNAs. The emitted signals were quantified, normalized and the data were statistically analyzed to verify the differentially expressed genes. According to the data, 104 genes were differentially expressed in XDM2 and 30 genes in BCYE media. The present study showed that DNA microarray technique efficiently differentiate the expressed genes under different conditions.

O gênero Fusarium é responsável por doenças em diversas plantas economicamente importantes. Entre estas doenças, destaca-se a malformação da mangueira, causada pelo fungo Fusarium subglutinans. O objetivo deste trabalho foi desenvolver oligonucleotídeos iniciadores para reação em cadeia da polimerase (PCR), específicos para o fungo F. subglutinans da mangueira. A amplificação de DNA de oito Fusarium spp. de diferentes hospedeiros, usando o oligonucleotídeo randômico UBC-41 (TTAACCGGGG), produziu um fragmento de aproximadamente 1.300 pb somente para o fungo da mangueira. Tendo em vista que padrões de bandeamento por RAPD não são considerados confiáveis devido à baixa reprodutibilidade dos resultados, o fragmento diferencial foi eluído do gel de agarose, purificado, clonado e seqüenciado. As seqüências nucleotídicas foram utilizadas para identificar e sintetizar quatro pares de oligonucleotídeos específicos, denominados Fs 5, Fs 13, Fs 14 e Fs 15. DNAs de Fusarium spp. de outros hospedeiros (alho, amendoim, cana-de-açúcar, ciclâmen, ervilha, melão e trigo), da planta de mangueira cv. Tommy Atkins sadia e de outros cinco isolados de F. subglutinans de mangueira sintomática, foram submetidos à amplificação com os pares de oligonucleotídeos. Fragmentos amplificados foram visualizados somente para F. subglutinans de mangueira, demonstrando assim a especificidade dos oligonucleotídeos SCAR desenhados.

The Fusarium genus is responsible for serious diseases in many economically important crops. Among these diseases it is distinguished the mango flower malformation, caused by the fungus Fusarium subglutinans. The objective of this work was to develop specific oligonucleotide primers for the polymerase chain reaction (PCR) targeting the mango flower malformation by fungus F. subglutinans. The DNA amplification of eight Fusarium spp. collected from different hosts making the use of a random oligonucleotide primer UBC-41 generated a fragment of approximately 1300 pb in size, specifically for the mango flower malformation fungus (Fusarium subglutinans). Since standard RAPD banding patterns are not considered reliable because of their low results of reproducibility, the distinctive fragment was eluted off the agarose gel, purified, cloned and then sequenced. The nucleotide sequences were used to identify and also to synthesize four pairs of specific oligonucleotide named herein Fs 5, Fs 13, Fs 14 and Fs 15. Other Fusarium spp. DNAs sampled from other hosts (garlic, peanut, sugarcane, cyclamen, pea, melon and wheat), from a healthy mango tree cv. Tommy Atkins and other six isolates from symptomatic mango plants were submitted to PCR amplification with these pairs of oligonucleotide. Only fragments from the mango tree fungus Fusarium subglutinans were visualized, showing this way the SCAR oligonucleotide specificity.