Replication of macronuclear DNA in the cytoplasm of Tetrahymena pyriformis.

Replication and Functions of Macronuclear Dna in Synchronously Growing Populations of Tetrahymena Pyriformis

Regulation of ribosomal RNA synthesis in Tetrahymena pyriformis.

Ribosomal RNA is synthesized at constant rate during most of the cell cycle in heat-shock synchronized populations of Tetrahymena pyriformis. Early in each macronuclear S-period the rate of synthesis increases abruptly, concomitant with replication of the genes coding for ribosomal RNA. The increase is prevented by inhibitors of DNA replication, added prior to the S-period. Similarly, in cultur...

Causal relations among cell cycle processes in Tetrahymena pyriformis. An analysis employing temperature-sensitive mutants

Utilization of temperature-sensitive mutants of Tetrahymena pyriformis affected in cell division or developmental pathway selection has permitted elucidation of causal dependencies interrelating micronuclear and macronuclear replication and division, oral development, and cytokinesis. In those mutants in which cell division is specifically blocked at restrictive temperatures, micronuclear divis...

Electron-microscopic observations on the macronuclear development of Stylonychia mytilus and Tetrahymena pyriformis (Ciliophora-Protozoa).

This report describes an ultrastructural investigation of macronuclear development following conjugation in Stylonycltia mytilus (a spirotrichous ciliate) and Tetrahymena pyriformis (a holotrichous ciliate). In S. mytilus, polytene chromosomes are formed in the young macronucleus (macronuclear Anlage). They are subsequently broken between the bands by 'membranous' partitions; the assembly of th...

The Fine Structure of the Nuclei of Tetrahymena Pyriformis throughout the Cell Cycle

The fine structure of the nuclei of logarithmically growing Tetrahymena pyriformis, strain HSM, was studied at 30-minute intervals throughout the cell cycle. Organisms were selected at similar stages of cytokinesis by means of a braking pipette, incubated, fixed in OsO(4), and embedded in agar to facilitate subsequent preparation for electron microscopy. Aggregates of micronuclear chromatin und...

[6n]methyl Adenine in the Nuclear Dna of a Eucaryote, Tetrahymena Pyriformis

DNA isolated from macronuclei of the ciliate, Tetrahymena pyriformis, has been found to contain [(6)N]methyl adenine (MeAde); this represents the first clear demonstration of significant amounts of MeAde in the DNA of a eucaryote. The amounts of macronuclear MeAde differed slightly between different strains of Tetrahymena, with approximately 0.65-0.80% of the adenine bases being methylated. The...