Determining limiting processes of bacteriophage growth by varying ribosome content of bacterial hosts*

During an infection a bacteriophage utilises bacterial machinery to produce phage progeny and the enzymes used to lyse the host cell, releasing the progeny to infect other bacteria. Processes that are involved in the lytic cycle of bacteriophage can be either ribosome-dependent (such as the production of procapsids) or ribosome-independent (such as the adsorption rate of the phage to the surface of the cell).

            By measuring the population dynamics of the host bacteria whilst varying their ribosome content, as well as the initial multiplicity of infection, it is possible to determine whether dominant processes for the lytic cycle are ribosome dependant, and if so, the relationship between phage population dynamics and the ribosome number. Initial experiments with T1 phage showed that the growth of phage is independent of ribosome quantity and so limited by a ribosome-independent process. Experiments with T7 phage, which has an increased adsorption rate, are now performed to determine whether this behaviour is reproducible across phages.       

            A delay differential model has been applied to predict the relationships between ribosome-dependant and independent variables for one to dominate phage growth over the other.