New nucleic dyes for pico-and nanoplankton cytometric analysis

Abstract

Flow cytometry (FCM) is a promising tool in the field of aquatic phytoplankton ecology because it allows for multi-parameter assessment of the physiological state of individual cells in an algal population. It can help to elucidate major questions such as phytoplankton taxa identification, the evaluation of cell quantity and viability, and the measuring of phytoplankton and general microbial metabolic activities. Traditionally, microalgal characterization is performed by microscopic analysis using UV-excited nuclear dyes (e.g. Hoechst and DAPI) or dyes that are excited in the blue-green part of the spectrum such as propidium iodide and eosin. The development of multi-laser cytometric systems has widened the possibilities for multi-parametric analysis and cell sorting of phytoplankton populations. Notwithstanding, significant algae autofluorescence originating from different types of chlorophyll and accessory pigments may overlap with propidium iodide and/or eosin staining and affect the resolution of algae clusters and cell sorting.