Involvement of the bacterial groM gene product in bacteriophage T7 reproduction. II. A reduced level of ion concentrations causes the blockage of T7 maturation in K-12-M cells.

Cellular leakage observed in Escherichia coli K-12-M shortly after T7 infection might be the cause of arrested phage morphogenesis. We observed in this strain, but not in the normal host, a drastic reduction of the intracellular concentration of potassium (60%), magnesium (40%), putrescine (90%), and spermidine (40%), whereas ATP was not significantly reduced. Leakage started about 1 min after the addition of phage and was arrested 3 to 5 min postinfection. Larger molecules such as o-nitrophenyl-beta-D-galactopyranoside could not enter the cells, showing that the permeability of the membrane was not generally affected. To prevent their leakage, we increased the outside concentrations of several small molecules and ions. The yield of progeny phage was substantially increased by the addition of 100 mM MgSO4.