DNA Contents of Cell Nuclei in Two Cyanidiophyceae: Cyanidioschyzon merolae and Cyanidium caldarium Forma A.

The DNA contents in the cell nuclei of the Cyanidiophyceae C. merolae and C. caldarium Forma A were estimated using VIMPCS after staining with DAPI, Schiff's reagent or PI. For C. merolae, the obtained data were compared with those of PFGE. The results indicated that the genome sizes of C. merolae and C. caldarium Forma A were approximately 13 Mbp and 35 Mbp, respectively. Since the values obtained by PFGE were very close to those estimated from Feulgen staining, Schiff's reagent, which binds to purine residues and is not affected by GC content, is considered to be the most reliable of these three reagents for estimating DNA contents.