Effect of Bacteriophage Ghost Infection on Protein Synthesis in Escherichia coli

Abstract

The rate of protein synthesis by Escherichia coli markedly decreased within 1 min after phage T4 infection, whereas a complete cessation of protein synthesis was observed within at least 25 sec after T4 ghost infection. The cellular level of amino acids and aminoacyl-transfer ribonucleic acid (tRNA) did not change drastically upon infection with ghosts, indicating that the inhibition of protein synthesis took place at a step(s) beyond aminoacyl-tRNA formation. The host messenger RNA remained intact and still bound to ribosomes shortly after ghost infection. Kinetic studies of the effect of ghosts on host protein synthesis revealed that nascent peptide chains on ribosomes were not released upon ghost infection. Casamino Acids to a final concentration of 0.2%c. TY broth contained 10 g of tryptone, 5 g of yeast extract, and 10 g of NaCl per liter. Growth and infection of bacteria. Cells of E. coli B were grown at 37 C in an Eberbach reciprocal shaker. Growth was measured in a Klett colorimeter, and the Klett reading had been calibrated to the number of colony formers in the culture media. The mass doubling times were 50, 50, and 30 min, in TG medium, TGA medium, and TY broth, respectively. Cells were grown to a densitv of I to 5 X 108 cells/ml and were 713

Presence of active polyribosomes in bacterial cells infected with T4 bacteriophage ghosts

“…Phage T4 D was used for the preparation of T4 D phage ghosts. E. coli B was grown at 37 C as described previously (6). Unless noted otherwise, cells were infected with T4 ghosts at a multiplicity of 10 in the presence of L-tryptophan (20 jg/ml).…”

“…Preparation and titration of T4 ghosts. The procedure for preparation of crude T4 ghosts was described previously (6). The purification of the ghosts was performed according to the method of Duckworth (3) with a slight modification as described below.…”

“…The ghosts thus purified were assayed by a modification of the method of Duckworth and Bessman which measures inhibitory effect of ghosts on the induction of ,B-galactosidase (4) as described previously (6).…”

“…Infection of growing Escherichia coli B with DNA-less T4 phage particles, or T4 ghosts, causes abrupt stoppage of host protein synthesis (2,3,5,6). We previously reported that the cellular level of aminoacyl tRNA did not change significantly upon ghost infection, and that there was virtually no leakage or degradation of proteins and RNA into acid-soluble materials after infection (6). It has been suggested that ghost infection may result in a damage of ribosomal function for protein synthesis (13).…”

Staphylococcus bacteriophage tails with bactericidal properties: New findings

“…Phage replication can be prevented through osmotic shock, which extracts the DNA, thereby producing bacteriophage ghosts . Bacterial infection with phage ghosts inhibits cellular respiration and synthesis of protein, DNA, and RNA more efficiently than intact phages . Other means of eliminating functionally active DNA include mechanical separation of the head and tail of the fully assembled virion .…”