COMPUTER-ANALYSIS OF LIVING CELLS - MOVEMENTS OF THE CHROMATOID BODY IN EARLY SPERMATIDS COMPARED WITH ITS ULTRASTRUCTURE IN SNAP-FROZEN PREPARATIONS

Quantitative analyses of cytoplasmic and nuclear organelle movements i n living interphase cells at defined stages of differentiation are few . By phase contrast videomicroscopy and digital imaging techniques, we have traced the path of the chromatoid body (CB) and analysed its rap idly changing positions in relation to the nuclear envelope, Golgi com plex and nuclear pale chromatin areas in living early spermatids of th e rat. The CB had intimate interactions with the nuclear envelope and moved bath in parallel and perpendicular fashion in relation to it. It had successive short contacts with the Golgi complex and nuclear pale chromatin areas. It was also seen to scan between two pale chromatin areas and it had pinocytosis-like transient engulfments during interac tions with the pale chromatin. In ultrastructural analysis of snap-fro zen preparations, the CB had a large contact area with the nuclear env elope with several intermediate organelles that may be involved in nuc leocytoplasmic material transport. It is evident that quantitative ima ge analysis of living cells is a powerful guide for ultrastructural an alyses. The snap-freezing technique gives new possibilities for studie s of structures that are sensitive to conventional fixation procedures .