Abstract: | Nuclei were isolated from Peridinium cinctum. Peridinium trochoideum, Gyrodinium cohnii (Cryptothecodinium cohnii) and Gymnodinium nelsoni. The nuclei of G. cohnii, P. trochoideum and G. nelsoni were found to contain ~ 6.9, 34 and 143 picograms of DNA respectively. The ratios to DNA of RNA, acid-soluble and acid-insoluble protein for G. cohnii were 0.32, 0.13 and 0.99, respectively. The corresponding values for P. trochoideum were 0.22, 0.08 and 1.22, while those for G. nelsoni were 0.21, 0.10 and 1.09. The chemical composition of dinoflagellate nuclei is compared and contrasted with that of typical eukaryotic nuclei. The culture of these difficult organisms also is discussed. |