MACRONUCLEAR CHROMATIN OF BLEPHARISMA-JAPONICUM COMPARED TO THAT OF TETRAHYMENA-PYRIFORMIS

The macronuclear chromatin of the ciliate Blepharisma japonicum was st udied by electrophoretic and immunological techniques as well as by mi crococcal nuclease digestion and circular dichroism spectroscopy. Unde r these experimental conditions the macronuclear chromatin of B. japon icum was compared to that of Tetrahymena pyriformis. Data obtained thr ough this analysis showed that the macronuclear chromatin of B. japoni cum is structurally more relaxed than that of T pyriformis. A perchlor ic acid soluble polypeptide, referred to as P3, is the only polypeptid e of B. japonicum chromatin to appear immunologically related to the H 1 histone of T pyriformis. It is suggested that this P3 polypeptide in B. japonicum should be considered functionally equivalent to the T py riformis H1 histone, even though it differed from it both in terms of molecular mass and relative concentration.