A STUDY ON MACRONUCLEAR CHROMATIN STRUCTURE IN COLPODA-INFLATA (PROTOZOA, CILIOPHORA) BY MEANS OF IMAGE-ANALYSIS

Resting encystment is a reversible cytodifferentiation phenomenon regu larly taking place during the life cycle of Colpodidae. The encystment involves regulation of the macronuclear DNA content, accomplished via chromatin extrusion and DNA synthesis mechanisms. An analysis of macr onuclear chromatin texture was carried out in Colpoda inflata logarith mically growing cells, pre-cystic cells, and increasingly aging restin g cysts after Feulgen staining. Morphometric and densitometric paramet ers as well as Markovian chromatin texture variables were utilised for image analysis. Moreover, univariate and multivariate analyses were a pplied both to macronuclei and to their chromatin extrusion bodies. Th e results show that structural variations in chromatin appear under ma cronuclear functional activity conditions, suggesting a dynamic state of chromatin texture throughout a long-term resting encystment.