E. Eschbach et al., A simple and highly efficient fixation method for Chrysochromulina polylepis (Prymnesiophytes) for analytical flow cytometry, CYTOMETRY, 44(2), 2001, pp. 126-132
Background: To study the fragile Prymnesiophyte species Chrysochromulina po
lylepis by flow cytometry (FC), we needed an effective fixation method. Thi
s method must guarantee a high yield of fixed cells to achieve acceptable m
easurement times by FC and to allow quick processing of many samples. Moreo
ver, we wanted a method that allows for storage of fixed samples when FC an
alysis cannot be done immediately.
Methods: Different aldehydes and methanol were tested at different final co
ncentrations. Gravity sedimentation and centrifugation were applied to achi
eve higher cell concentrations. Storage of fixed samples was tested under d
ifferent conditions.
Results: 0.25% glutaraldehyde (GA) fixation yielded a recovery rate of abou
t 90%. The signals obtained by FC analysis were excellent. It is possible t
o centrifuge GA-fixed cells and to store them for several weeks.
Conclusions: GA is the fixative of choice for FC analysis of C. polylepis (
and possibly other small delicate species) because it yielded highly signif
icant recovery rates and high-quality FC signals. Cells call be centrifuged
re, increase the cell concentration, thereby achieving short measurement t
imes with FC. The possibility of long-term storage of fixed cells presents
an additional advantage if FC analysis cannot be done immediately. Cytometr
y 44: 126-132, 2001. (C) 2001 Wiley-Liss, Inc.