Histone-antihistone interactions in Escherichia coli-Tetrahymena pyriformis association

Using the Escherichia coli-Tetrahymena pyriformis model system, we revealed the involvement of bacterial antihistone activity and protozoan histones in interactions between pro- and eukaryotic microorganisms. Antihistone activity enhanced the viability of E. coli in association with T pyriformis, according to our data on the dynamics of E. coli cell numbers. The strain with antihistone activity induced incomplete phagocytosis in the infusorians, resulting in cytological changes and ultrastructural alterations that indicated the retention of bacterial cells in phagosomes. Bacteria with antihistone activity located in the T pyriformis cytoplasm influenced the eukaryotic nucleus. This was accompanied by in macronucleus decompactization and a decrease in the average histone content in the population of infusorians. The data obtained suggest that protozoan histone inactivation by bacteria is one of the mechanisms involved in prokaryote persistence in associations with eukaryotic microorganisms.