X-ray microanalysis of chromatin-bound period IV metals inGlenodinium foliaceum: A binucleate dinoflagellate

Summary Each vegetative cell of the dinoflagellateGlenodinium foliaceum possesses two distinct types of nucleus, both of which have high levels of chromatin-bound Period IV (Periodic Table) metal elements.The typical dinoflagellate (dinocaryotic) nucleus has chromatin which differs from the atypical (supernumerary) nucleus in its high degree of condensation and in the related high levels of P, Ca, and Transition metals Fe, Ni, Cu, and Zn. The complete absence of detectable Fe and Ni in the supernumerary chromatin represents a major difference which may relate to differences in phyllogenetic origin of the two nuclei.The two types of chromatin show close similarities at the molecular level, including the possession of 40 atoms of Period IV elements per 100 atoms of P—of which approximately half are Ca atoms, and half Transition metals. In both cases, the levels of Ca and Zn show a high correlation with the level of P, suggesting a direct association of these particular metal atoms with nucleic acid phosphate groups. The close similarity in metal binding at the molecular level suggests that the association of Period IV elements with the two types of chromatin is unrelated to any differences in chromatin proteins—such as the presence or absence of histones.