The feasibility of counting plant-parasitic nematodes in aqueous suspensions by measuring light transmittance through aqueous suspensions with an ELISA microplate reader was explored. Absorbance readings for eggs or vermiform stages of three species were linearly related (R(2) > 0.99) to concentrations between 0 and 10,000 nematodes/ml. Coefficients of variation ranged from 12-23%, depending on...

A fluorometric assay in microtitre plates for the screening of phenylketonuria was evaluated and adapted to a neonatal screening programme. Using this assay, it is possible to determine quantitatively the phenylalanine concentration in dried blood spots on filter paper. The test exhibited a linear calibration curve with a good slope as well as sufficient precision and accuracy in the statistica...

Superoxide dismutases (SODs) catalyze the dismutation of superoxide radicals in a broad range of organisms, including plants. Quantification of SOD activity in crude plant extracts has been problematic due to the presence of compounds that interfere with the dose-response of the assay. Although strategies exist to partially purify SODs from plant extracts, the requirement for purification limit...

CLSI method M27-A3 is not available for use with dimorphic fungi, such as those of the Paracoccidioides genus. In this study, we developed a microdilution method and added the alamarBlue reagent to test the responses of Paracoccidioides brasiliensis and Paracoccidioides lutzii against amphotericin B and itraconazole antifungals. The test proved to be sensitive, practical, and inexpensive and ca...

Measurements of nonstructural carbohydrates (NSC) in plant tissues are important to estimate plant organ resources available for plant growth and stress tolerance or for feed value to grazing animals. A popular commercially available assay kit used to detect glucose with a lightsensitive dye reaction was recently discontinued and replaced by a test-tube-scale glucose kit (GAHK-20) that assays g...