[Comparative enzymatic study on the structure of chromatin in the nuclei of the growing microplasmodium of Physarum polycephalum]

Abstract

The structure of chromatin in the growing myxomycetes P. polycephalum can be interpreted on the basis of three types of substructure: (i) soluble in a low ionic strength buffer and 2 mM EDTA (I), (ii) soluble in 0.6 M NaCl (II) and (iii) non-soluble and nuclease-insensitive (III). The ratio of these structures in the nuclear pellet obtained after autolysis was found to be 71 : 0, 4 : 12 for the young and 7.7 : 62 : 20.6 for the old cultures, respectively. The ageing of the culture involves transition of substructure I to substructure II. The substructures differ in the nuclease sensitivity. The specific features of enzyme fragmentation of chromatin from P. polycephalum microplasmodium nuclei are discussed.