BACTERIOPHAGE-T4 DEVELOPMENT DEPENDS ON THE PHYSIOLOGY OF ITS HOST ESCHERICHIA-COLI

Several parameters of phage T4 adsorption to and growth in Escherichia coli B/r were determined. All changed monotonously with the bacterial growth rate (mu), which was modified by nutritional conditions. Adsor ption rate was faster at higher mu values, positively correlated to ce ll size, and increased by pretreatment with low penicillin (Pn) concen trations; it was directly proportional to total cellular surface area, indicating a constant density of T4 receptors on cell envelopes irres pective of growth conditions. Parameters of phage development and cell lysis were mu-dependent. The rate of phage release and burst size inc reased, while the eclipse and latent periods decreased with increasing mu. Differentiation between the contribution of several physiological parameters to the development of T4 was performed by manipulating the host cells. A competitive inhibitor of glucose uptake, methyl alpha-D -glucoside, was exploited to reduce the growth rate in the same effect ive carbon source. Synchronous cells were obtained by the 'baby-machin e' and large cells were obtained by pretreatment with low Pn concentra tions. Lysis was delayed by superinfection, and DNA content and concen tration were modified by growing a thy mutant in limiting thymine conc entrations. The results indicate that burst size is not limited by cel l size or DNA composition, nor directly by the rate of metabolism, but rather by the rates of synthesis and assembly of phage components and by lysis time. The rates of synthesis and assembly of phage component s seem to depend on the content of the protein-synthesizing system and lysis time seems to depend on cellular dimensions.