Metodologias de preparação de amostras de ferrugem para estudos morfológicos de urediniósporos por meio de microscopia eletrônica de varredura

Abstract

Samples from Urediniospores of some rust fungi such as Melampsora epitea, Melampsora medusae, Hemileia vastatrix, Uromyces appendiculatum, Puccinia sorghi, Tranzschelia discolor and Phakopsora euvitis respectively from Salix sp., Populus deltoides, Coffea arabica, Phaseolus vulgaris, Zea mays, Prunus persicae and Vitis vinifera, were processed by three different methodologies for scanning electron microscopy (SEM) observations. These methodologies were: a) conventional methodology (glutaraldehyde and osmium tetroxide fixation, dehydrated in an acetone series, dried in a critical point dryer and sputtered with gold); b) fixation using osmium tetroxide vapor technique and sputtering with gold and c) direct sputtered of the samples with gold (with free urediniospores).May De Mio, L. L.; Novaes, Q. S; Alves E. Methodologies processed of some rusts fungi by scanning electron microscopy. Summa Phytopathologica, v.32, n.3, p.267-273, 2006.Also fractures of leaf sample frozen in liquid nitrogen were used to observe details within the uredia from grape rust (P. euvitis). The samples were observed in a scanning electron microscope (SEM) LEO 435VP and the images were captured and recorded by using the software LeoUserInterface and processed with Corel Photopaint 9.0 software. The dimension of the urediniospores was also measured. Regardless of the technique the structure of the urediniospores were very well preserved resulting in images of high quality. However the technique of direct sputtering was more useful and quick to see the urediniospores. The liquid nitrogen fractures allowed a perfect observation from the interior of the grape rust uredia. RESUMOAmostras de urediniósporos de ferrugens das espécies Melampsora epitea Thum., Melampsora medusae Thuem., Hemileia vastatrix Berk., Uromyces appendiculatum Pers., Puccinia sorghi Schwein., Tranzschelia discolor Fuckel e Phakopsora euvitis Ono, coletadas dos hospedeiros, chorão (Salix sp.), álamo (Populus deltoides Bartr. Ex. Marsh), cafeeiro (Coffea arabica L.), feijoeiro (Phaseolus vulgaris L.), milho (Zea mays L.), pessegueiro (Prunus persicae L.) e videira (Vitis vinifera L.) respectivamente, foram processadas de 3 formas: a) método convencional (fixação em glutaraldeído e tetróxido de ósmio, desidratação em acetona e secagem ao ponto crítico); b) método do vapor de ósmio e metalização com ouro; c) metalização direta de amostras (utilizado para esporos soltos). A técnica de fratura de amostra congelada em nitrogênio líquido também foi testada para o estudo do interior de pústulas da ferrugem da videira (P. euvitis). As amostras foram visualizadas em microscópio eletrônico de varredura no NAP/ MEPA da ESALQ/USP. Procedeu-se à mensuração dos esporos e as imagens obtidas foram capturadas pelo software LeoUserInterface e processadas utilizando-se o programa de computador "Corel Draw". Em todos os métodos analisados obteve-se uma boa preservação da estrutura possibilitando imagens de alta qualidade. No entanto, para esporos livres (mantidos em cápsula de gelatina) o ...

In VitroAntifungal Activity of Hexahydropyrimidine Derivatives against the Causative Agents of Dermatomycosis

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Morphology and infection process of Olivea neotectonae in teak leaves

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