A survey of the literature of tissue cultivation does not disclose much information on enzymes in this particular branch of experimental biology (1). The majority of writers dealing with phosphomonoesterases in cultivated cells (2, 3), with the exception of Fell and Robinson (4, 5), applied histochemical tests (6), which do not permit quantitative evaluation. We followed the activities of various enzyme systems in normal tissue cultures (TC) by biochemical methods (7,8). Using similar techniques striking changes were observed in nine enzyme systems of cells infected with various strains of poliomyelitis virus and the findings published in a preliminary report (9). The present publication deals exclusively with various aspects of phosphatase activities in virus-inoculated TC and in normal controls. Previous works in this field were made mostly on organ homogenates of experimental animals (10), containing all the products of inflammatory reactions of the host. Our contribution on relatively simple systems concerns the mechanism of drastic modifications in cell physiology during poliomyelitis infection, in vitro.
MethodsOnly the variations in the handling of TC will be mentioned here; for more information and the general methods the reader is referred to the previous papers of this series (7-9).Explants.--Tissue cultivation, virus production, and titration were made by the Poliomyelitis Assay Department. I Most of the experiments were carried out on roller tubes of trypsin~zed rhesus monkey kidney cortex, grown about 14 days with synthetic nutrient 199 (11) and later with a modified form of it, termed medium 597 (7). The roller tube cultures were inoculated with various dilutions of virus, generally 24 hours after the second fluid change, and were incubated in roller drums at 37°C. for 6 days (12). For calculation of the titre K~.rber's method was used (13) and virus concentration was expressed in negative logarithms (14). Specially designed experiments were run with large inocula