[Change in certain physical characteristics of cells at various stages of the cell cycle]

Experiments on semisynchronized cultures of animal and plant cells, performed in our laboratory approximately 30 years ago, have demonstrated that there exist regular changes of certain physical parameters of the cells during the cell cycle. In particular on yeast cultures there has been observed the appearance of specific electron paramagnetic resonance (EPR) signals with simultaneous change of the static magnetic susceptibility of the cultures in the period immediately preceding the beginning of the intensive budding. On chlorella cultures grown at certain regimes of light and darkness it is possible to observe characteristic changes of the kinetics of the photoconduction signal at the frequency of 10 HHz (SHR-photoconduction). It can be conjectured that these effects are of a similar nature linked to some changes of the intracellular structures at certain stages of the cell cycle. The work performed much later makes it possible to link these changes to the appearance of spin, glass-like structures in macromolecular intracellular bodies.