Ca. Jerome et al., THE EFFECT OF THE QUANTITATIVE PROTARGOL STAIN AND LUGOLS AND BOUINS FIXATIVES ON CELL-SIZE - A MORE ACCURATE ESTIMATE OF CILIATE SPECIES BIOMASS, The Journal of eukaryotic microbiology, 40(3), 1993, pp. 254-259
The quantitative protargol stain (QPS) is used to estimate ciliate bio
mass and species composition from mixed field samPles. Length, width,
breadth and volume of live Euplotes sp., Eutintinnus sp., Strobilidium
spiralis, Strombidium acutum, and Gymnodinium sanguineum were compare
d with 0.6% acid Lugol's fixed, 5% Bouin's fixed, and QPS cells. Cells
shrank due to treatments (ANOVA and Tukey's test, alpha = 0.05). Prot
istan post-fixation cell volume (as a percentage of live volume) was 5
5%-80% for acid Lugol's fixed, 40%-70% for Bouin's fixed, and 30%-65%
for QPS. Each species shrank to a different extent; cytostructural ele
ments apparently alter the effect of fixation. Egestion is likely not
the main cause of shrinkage since the autotroph, G. sanguineum, shrank
to the same extent as the heterotrophs when stained by QPS. If field
studies do not consider fixation effects on cell size, biomass may be
underestimated. We recommend, for studies on planktonic ciliates, eith
er acid Lugol's and QPS be used concurrently or QPS be used alone and
biovolume values divided by 0.4 to correct for shrinkage. We stress th
at this is a rough estimate as this value ranges from 0.3 to 0.45 for
planktonic protists.