Alexander Kirillov, Natalia Morozova, Vasilisa Polinovaskaya, Sergey Smirnov and Konstantin Severinov published a preprint “Cells with Stochastically Increased Methyltransferase to Restriction Endonuclease Ratio Provide an Entry for Bacteriophage into Protected Cell Population” at bioRxiv. The scientists show that protection from phage infection increases as the copy number of plasmids carrying the Esp1396l restriction-modification (RM) system is increased. They discovered that a shift in the methyltransferase (MTase) to restriction endonuclease (REase) ratio caused by overproduction of MTase or REase leads, respectively, to decreased or increased protection from infection. Consistently, due to stochastic variation of MTase and REase amount in individual cells, bacterial cells that are productively infected by bacteriophage have significantly higher MTase to REase ratios than cells that ward off the infection. Full text of the preprint is available here.