Extracellular phosphatase activity of natural plankton studied with ELF97 phosphate: fluorescence quantification and labelling kinetics

• DOI: 10.1046/j.1462-2920.2003.00431.x
• Publication Date: 2003-05-19T14:37:26Z
• Authors: Jiří Nedoma; Alena Štrojsová; Jaroslav Vrba; Jaroslava Komárková; Karel Šimek
• Keywords: 0301 basic medicine; Fresh Water; Plankton; Phosphoric Monoester Hydrolases; 03 medical and health sciences; Organophosphorus Compounds; Spectrometry, Fluorescence; Phytoplankton; Image Processing, Computer-Assisted; Quinazolines; Czech Republic; Fluorescent Dyes; Quinazolinones

Summary ELF ® 97 phosphate (ELFP) is a phosphatase substrate which produces alcohol (ELFA), fluorescent water‐insoluble product, upon hydrolysis. We studied the kinetics of ELFA precipitation in freshwater samples at levels total plankton and single phytoplankton cells, tested suitability ELFP for measurement surface‐bound algal extracellular phosphatases. Samples from acidic Plešné Lake (pH ∼ 5; high activity) eutrophic Římov reservoir ∼7–10; moderate were incubated with 5–300 min, fixed HgCl 2 filtered through polycarbonate filters. Relative fluorescence filter‐retained precipitates was quantified image analysis. Time‐courses formation exhibited lag periods followed by finite linear increase. In Lake, lag‐times shorter (1–18 min) rates increase higher (by ∼2 orders magnitude) than (lag‐times 30–200 min). Similar patterns also observed cuvette spectrofluorometer measurements (which failed reservoir). Linear regression seasonal data on cytometry spectrofluorometry ( r = 0.65, n 10) allowed calibration terms amount cell‐associated ELFA. Preliminary activities several algae resulted (10–2260 fmol cell −1 h ) are comparable to reported literature cultures.