Chromatin structure in the unicellular algae Olisthodiscus luteus, Crypthecodinium cohnii and Peridiniun balticum
Rizzo, P.J.; Burghardt, R.C.
Chromosoma 76(1): 91-99
1980
ISSN/ISBN: 0009-5915 PMID: 7358010 Document Number: 159481
Isolated nuclei of the unicellular alga O. luteus, the uninucleate dinoflagellate C. cohnii and the binucleate dinoflagellate P. balticum were lysed and deposited on grids by the microcentrifugation technique. The ultrastructure of the released chromatin fibers was compared to that of mouse liver nuclei. Chromatin from nuclei of O. luteus and the eukaryotic nuclei of P. balticum appeared as linear arrays of regularly repeating subunits which were identical in size and morphology to mouse nucleosomes. The chromatin fibers from G. cohnii nuclei appeared as smooth threads with a diameter of .apprx. 6.5 nm. Nuclear preparations containing mixtures of dinokaryotic and eukaryotic nuclei of P. balticum also contained smooth fibers which most likely originated from the dinokaryotic nuclei. These and other results demonstrating the presence of nucleosomes in lower eukaryotes suggest that the subunit structure of chromatin arose very early in the evolution of the eukaryotic cell.