Flow cytometric detection of phosphatase activity combined with 13C-CO2 tracer-based growth rate assessment in phytoplankton populations from a shallow lake

Aquatic Microbial Ecology

Hans L. Hoogveld¹  Roel Pel¹  Marco Dignum¹  Hans C. P. Matthijs¹  Herman J. Gons¹  Virgilio Floris¹ 

关键词: Alkaline phosphatase;    Enzyme-labelled fluorescence;    Filamentous cyanobacteria;    Fluorescence-activated cell sorting;    Population-specific growth rate;    Phytoplankton;    Stable isotope labelling;   

DOI  :  10.3354/ame037159

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: To determine nutrient availability and growth rates of phytoplankton on a population level, improvement of discriminative power in fluorescence-activated cell sorting is required. We have combined fluorescence of the endogenous photosyntheticpigments chlorophyll a and phycocyanin with a phosphate deficiency (P-deficiency) related stain (enzyme-labelled fluorescence, ELF-97) that yields green fluorescent precipitates at the site of phosphatase activity, referred to as ELF alcohol (ELFA)fluorescence, to sort phytoplankton from Lake Loosdrecht (The Netherlands). Stable isotope labelling with ¹³C-enriched CO₂ enabled assessment of specific growth rates of sorted populations by pyrolytic methylation-gas chromatographyand in-line compound specific isotope-ratio mass spectrometry. The dominant population in the lake, the filamentous cyanobacterium Limnothrix sp., was growing under P-deficiency in spring, but the availability of phosphate increased in summer.Continuous flow of phosphate-rich medium into a laboratory-scale enclosure of lake water resulted in washout of the cells with ELFA fluorescence, and increased growth rates. In addition, this study revealed population heterogeneity within the cluster ofphycocyanin-containing cyanobacteria. ELFA fluorescence thus reflects the level of P-deficiency of freshwater cyanobacteria and micro-algae, but is modulated by metabolic activity of cells within the population.

【 授权许可】

Unknown