Original paper

Live sorting and survival of unstained and DAPI-stained ciliates by flow cytometry

Lindström, Eva S.; Stadler, Peter; Weisse, Thomas


The potential of flow cytometry in the study of unpigmented planktonic protozoa is to a large extent unexplored. The goal of this study was to develop a protocol for single cell live sorting of freshwater ciliates which can be applied in future laboratory experiments. Unstained and DAPI-stained specimens of four species of common prostomatid freshwater ciliates were sorted and their survival and growth were then monitored in micro-well plates. Three out of four species investigated (Urotricha farcta, Urotricha castalia, and Coleps spetai) grew after sorting. For the two Urotricha species up to 92-100% of the sorted cells grew after sorting, depending on DAPI-concentration. For C. spetai up to 25% grew. The smallest and most delicate species, Balanion planctonicum, was difficult to sort unstained and appeared not to grow after single cell sorting. DAPI-staining at concentrations ranging from 0.1 to 5μg DAPIml-1 improved flow cytometric discrimination between the ciliates and non-target particles in the samples. The impact of DAPI-staining on the growth of the sorted cells differed between species. However, three of the four species tested grew reasonably well after staining with 0.1μg DAPIml-1. We expect that this staining and sorting protocol may greatly facilitate and improve future experiments with cultured ciliates.


ciliatesflow cytometrylive sortingdna-staindapi.