Macronuclear chromatin of Blepharisma japonicum compared to that of Tetrahymena pyriformis

Abstract The macronuclear chromatin of the ciliate Blepharisma japonicum was studied by electrophoretic and immunological techniques as well as by micrococcal nuclease digestion and circular dichroism spectroscopy. Under these experimental conditions the macronuclear chromatin of B. japonicum was compared to that of Tetrahymena pyriformis . Data obtained through this analysis showed that the macronuclear chromatin of B. japonicum is structurally more relaxed than that of T. pyriformis . A perchloric acid soluble polypeptide, referred to as P3, is the only polypeptide of B. japonicum chromatin to appear immunologically related to the H1 histone of T. pyriformis . It is suggested that this P3 polypeptide in B. japonicum should be considered functionally equivalent to the T. pyriformis H1 histone, even though it differed from it both in terms of molecular mass and relative concentration.