[Activity of intracellular and extracellular nuclease according to the phases of growth of pigment and pigment-free strains of Serratia marcescens].

Changes in the activity of intracellular and extracellular nuclease of pigment and pigment-free strains of Serratia marcescens were studied. The activity of intra- and extracellular nuclease of the pigment-free strain was higher than that of the pigment strain at all growth stages of the microorganism. The activity of intracellular nuclease in the lag-phase was higher than in the phase of exponential growth of both strains. Prior to cell division the enzyme activity declined in both strains. At the beginning of the stationary phase the activity of intracellular nuclease was relatively stable in both strains. By the end of the stationary phase the activity of intracellular nuclease of the pigment-free strain increased 4--6 fold and that of the pigment strain remained unchanged. Simultaneously the activity of extracellular nuclease of the pigment-free strain increased and that of the pigment strain grew but slightly.