Polyamines permit the preparation of stable Physarum core particles which have a structure similar to those from higher eukaryotes.

The inherent instability of Physarum nucleosome core particles prepared by micrococcal nuclease digestion in Na+/Ca2+ buffers can be overcome by the addition of 0.15 mM spermine and 0.5 mM spermidine. Neutron scattering, circular dichroism, nuclease digestion and thermal denaturation studies carried out on these stable monosomes show them to be very similar to those obtained from higher eukaryotes.

A further assessment of the sub-nucleosomal product, "peak A", from Physarum polycephalum.

Nuclease digestion studies of Physarum polycephalum nuclei (1-3) and nucleoli (4) over the past few years have been centred on a number of modified nucleosomal products which have been related to active-gene regions of the genome. We have re-investigated one such particle, peak A, using the techniques of differential melting and polyacrylamide gel electrophoresis and show that this material is unlikely to be a specific histone:DNA complex as suggested by earlier authors.