naa a22 4500 510748813 CHVBK 20180411083057.0 cr unu---uuuuu 180411e20130101xx s 000 0 eng 10.1007/s11270-012-1358-3 doi (NATIONALLICENCE)springer-10.1007/s11270-012-1358-3 Optimization of a Microplate-Based Assay to Assess Esterase Activity in the Alga Pseudokirchneriella subcapitata [Elektronische Daten] [Manuela Machado, Eduardo Soares] The present work describes the optimization of a short-term assay, based on the inhibition of the esterase activity of the alga Pseudokirchneriella subcapitata, in a microplate format. The optimization of the staining procedure showed that the incubation of the algal cells with 20μmol L−1 fluorescein diacetate (FDA) for 40min allowed discrimination between metabolic active and inactive cells. The short-term assay was tested using Cu as toxicant. For this purpose, algal cells, in the exponential or stationary phase of growth, were exposed to the heavy metal in growing conditions. After 3 or 6h, cells were subsequently stained with FDA, using the optimized procedure. For Cu, the 3- and 6-h EC50 values, based on the inhibition of the esterase activity of algal cells in the exponential phase of growth, were 209 and 130μg L−1, respectively. P. subcapitata cells, in the stationary phase of growth, displayed higher effective concentration values than those observed in the exponential phase. The 3- and 6-h EC50 values for Cu, for cells in the stationary phase, were 443 and 268μg L−1, respectively. This short-term microplate assay showed to be a rapid endpoint for testing toxicity using the alga P. subcapitata. The small volume required, the simplicity of the assay (no washing steps), and the automatic reading of the fluorescence make the assay particularly well suited for the evaluation of the toxicity of a high number of environmental samples. Springer Science+Business Media Dordrecht, 2012 Bioassay nationallicence Fluorescein diacetate (FDA) nationallicence Growth phase nationallicence Microplate assay nationallicence Metabolic activity nationallicence Selenastrum capricornutum nationallicence Machado Manuela Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of the Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072, Porto, Portugal aut Soares Eduardo Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of the Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072, Porto, Portugal aut Water, Air, & Soil Pollution Springer Netherlands 224/1(2013-01-01), 1-11 0049-6979 224:1<1 2013 224 11270 https://doi.org/10.1007/s11270-012-1358-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11270-012-1358-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Machado Manuela Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of the Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072, Porto, Portugal aut NATIONALLICENCE 700 1- Soares Eduardo Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of the Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072, Porto, Portugal aut NATIONALLICENCE 773 0- Water, Air, & Soil Pollution Springer Netherlands 224/1(2013-01-01), 1-11 0049-6979 224:1<1 2013 224 11270 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer