Inhibition of T4 bacteriophage multiplication by superinfecting ghosts and the development of tolerance after bacteriophage infection

Alteration of the Escherichia coli membrane by addition of bacteriophage T4 protein synthesized after infection

Many T4-induced proteins were found associated with the Escherichia coli membrane during infection. Some of these were apparently ionically bound, but many could be identified as integral parts of the inner and outer bacterial membranes by their selective solubilities in guanidine or Sarkosyl. The synthesis and insertion of these proteins into the bacterial membrane were temporally controlled and, once in the membrane, these proteins were stably integrated. Host membrane protein synthesis continued after infection of non-UV-irradiated cells, but was not present, if the cells were irradiated. There were no major redistribution or loss of bacterial proteins from E. coli membranes as a consequence of T4 infection.

Recovery of the accumulation ability of thiomethyl-beta-galactoside in Escherichia coli after bacteriophage T4 infection

Effects of UV-irridiated and unirradiated T4 phage infection on the beta-galactoside accumulation ability in Eschericia coli have been examined by the use of 14C-labeled thiomethyl-beta-galactoside (TMG). Under conditions where a synchronous adsorption of phage takes place, the cellular ability for TMG accumulation is found to be largely inhibited immediately after phage adsorption, but it recovers with time to a new level, which is dependent on the multiplicity of infection. When cells are infected with UV-irradiated T4 at the same multiplicity as that of unirradiated phage, the cellular accumulation ability is more severely inhibited and there is no recovery from the inhibition. The recovery process in T4-infected cells is mostly sensitive to puromycin. These results suggest that the initial inhibition of the TMG accumulation ability is probably caused by the adsorption of phage coats, and the subsequent restoration occurs through the action of a phage-directed protein(s). In the recovery process, no new transport system appears to be involved. The restored ability of TMG accumulation is resistant to the action of superinfecting UV phage. However, different mechanisms appear to be operating in T4-infected cells for the establishment of resistance to ghosts and for the recovery from the phage coat-induced inhibition.

Bacteriophage T4-induced shut-off of host-specific translation

To study the mechanism by which bacteriophage T4 inhibits the synthesis of inducible host enzymes we measured the formation of beta-galactosidase from preformed lac mRNA. Beta-Galactosidase was induced with isopropyl-beta-D-thiogalactopyranoside in the presence of 7-azatryptophan, a tryptophan analogue that is incorporated into proteins and renders the beta-galactosidase formed inactive. The accumulated las mRNA was measured by capacity to form active beta-galactosidase after a chase of the analogue with excess tryptophan. After T4 infection the ability to form beta-galactosidase from the preformed lac mRNA was rapidly lost even when T4 infection took place in the presence of rifampin. This restriction was dependent on the multiplicity of infection. At a multiplicity of infection of 8.6, 90% of the ability to express preformed lac mRNA was lost within 30 s. The kinetics of cessation of beta-galactosidase synthesis after T4 infection indicate that infection blocks initiation of lac mRNA translation.

Phospholipase activity in bacteriophage-infected Escherichia. II. Activation of phospholipase by T4 ghost infection

The release of free fatty acids from the phospholipids of Escherichia coli is initiated immediately after the attachment of T4 ghosts. A similar accumulation of free fatty acids is observed if the cells are infected with T4 phage in the presence of chloramphenicol or puromycin. An early accumulation of free fatty acids, however, is not observed in T4 infections in which chloramphenicol or puromycin are not present, nor does it occur if the E. coli are infected with T4 phage before ghost infection, suggesting that phage products can prevent the phospholipid deacylation. If E. coli is infected with T4 ghosts before T4 phage infection, the accumulation of free fatty acids is not suppressed. When phospholipase-deficient E, coli are infected with T4 ghosts the appearance of free fatty acids is not observed, suggesting that T4 ghost attachment can activate the phospholipase of wild-type E. coli. Although the formation of free fatty acid apparently is a consequence of activation of the detergent-resistant phospholipase of the outer membrane, it is not observed in mutants deficient in the detergent-sensitive phospholipase.

Spackle and immunity functions of bacteriophage T4

Cells of Escherichia coli B infected with the immunity-negative (imm2) mutant of bacteriophage T4 are able to develop a substantial level of immunity to superinfecting phage ghosts if the ghost challenge is made late in infection. This background immunity is not seen in infections with phage carrying the spackle (s) mutation in addition to the imm2 lesion. The level of immunity in s(-) infections is intermediate between that of imm(-) and wild-type infections under standard assay conditions. With respect to genetic exclusion of superinfecting phage, cells infected with imm(-) phage are completely deficient, whereas infections with the s(-) phage are only partially deficient compared to wild-type infections. Whereas s(-)-infected cells are unable to resist lysis from without by a high multiplicity of infection (MOI) of superinfecting phage, cells infected with imm(-) phage show less than wild-type levels of resistance and the majority of cells remaining intact are unable to incorporate leucine or form infective centers. Under conditions of superinfection by low MOI of homologous phage, imm(-)-infected cells are lysis inhibited, whereas s(-)-infected cells do not show this property. Superinfecting phage inject their DNA into imm(-)-infected cells with the same efficiency as seen in wild-type infections, but this efficiency is reduced when the cells are first infected with s(-) phage. The s function of T4 appears not only to affect the host cell wall as previously postulated by Emrich, but may also affect the junctures of cell wall and membrane with consequences similar to those of the imm function.

Localization of membrane protein synthesized after infection with bacteriophage T4

The synthesis of membrane protein after infection with bacteriophage T4 was examined. Protein constituents of both the cytoplasmic and outer membrane are made during the infective cycle. In addition, newly synthesized membrane protein is found in material which has a buoyant density greater than that of either of the two host membrane fractions. Polyacrylamide gel analyses and solubilization studies using the detergent Sarkosyl indicate that synthesis of most of the membrane proteins made during the first 5 min of infection is directed by bacterial genes. New membrane proteins synthesized at times greater than 6 min after infection appear to be distinct from those of the host, and new proteins of the outer membrane are different from those of the inner. Proteins in the new dense membrane fraction are similar to those of the outer membrane.

Association of the rIIA protein with the bacterial membrane

Cell membrane proteins synthesized after infection of Escherichia coli B with wild-type phage T4 and rIIA mutants were analyzed by dodecyl sulfate-polyacrylamide gel electrophoresis. A protein with an approximate molecular weight of 74,000 is present in membranes isolated from T4r(+)-infected cells, but is not found in membranes prepared from cells infected with an rIIA mutant in which the major part of the rIIA cistron is deleted. In addition, infection of E. coli B with different rIIA amber mutants and deletions gives peptides, which are associated with the bacterial membrane, of molecular weights consistent with the location of the respective mutations in the cistron. The rIIA protein is synthesized with delayed early kinetics. The synthesis of the rIIB protein, which is also located in the membrane, is not affected by mutations in the A cistron; conversely, synthesis of the rIIA protein is not affected by mutations in the B cistron. A mutant (rII 1589) contains a deletion that originates in the A cistron and extends into the adjacent B cistron. This mutant directs the synthesis of a compound membrane protein consisting of the undeleted portions of the A and B cistrons. The synthesis of the compound protein appears to be under the control of the A promoter.

Effect of inhibition of macromolecule synthesis on the association of bacteriophage T4 DNA with membrane

The "Mg(2+)-Sarkosyl crystals" (M band) technique distinguishes between membrane-bound and free intracellular DNA. This procedure was employed to investigate the nature of the reactions necessary to convert input T4 DNA to a rapidly sedimenting form. Energy poisoning inhibits this attachment reaction. Neither protein nor DNA synthesis appears to be required, but experiments with rifampin and extensively irradiated T4 suggest that RNA synthesis is involved. These results were confirmed by a second procedure for the determination of rapidly sedimenting DNA.

Superinfection exclusion by incomplete genomes of bacteriophage T4

The genetic basis of superinfection exclusion by bacteriophage T4 was investigated by using incomplete genomes derived from the gene 66 mutant E920g. Incomplete genomes, which included a region of T4 between genes 42 and 44, were able to exclude superinfecting phage with an efficiency similar to that of complete genomes. Those genomes which did not include this region were unable to exclude superinfecting phage. A mutant with reduced ability to exclude super-infecting phage was isolated after mutagenesis with hydroxylamine. The mutation maps midway between amN122 in gene 42 and amB22 in gene 43. The efficiency of exclusion of superinfecting phage (as measured by the percentage of superinfected cells which failed to release any phage carrying selected markers of the superinfecting phage) by this mutant was 50 to 60%, whereas for wild type it was 85 to 95%. Uptake of (3)H-leucine by cells infected with the mutant was inhibited by superinfection with ghosts and it has therefore been designated imm1, for lack of immunity to superinfecting phage and ghosts. The formation of infective centers by cells infected with imm1 or another imm(-) mutant (imm2) was not inhibited by superinfection with ghosts.

Nuclear disruption after infection of Escherichia coli with a bacteriophage T4 mutant unable to induce endonuclease II

Nuclear disruption after infection of Escherichia coli with a bacteriophage T4 mutant deficient in the ability to induce endonuclease II indicates that either (i) the endonuclease II-catalyzed reaction is not the first step in host deoxyribonucleic acid (DNA) breakdown or (ii) nuclear disruption is independent of nucleolytic cleavage of the host chromosome. M-band analysis demonstrates that the host DNA remains membrane-bound after infection with either an endonuclease II-deficient mutant or T4 phage ghosts.

Superinfection with bacteriophage T4: inverse relationship between genetic exclusion and membrane association of deoxyribonucleic acid of secondary bacteriophage

The majority of the deoxyribonucleic acid (DNA) of superinfecting T4 bacteriophage which is injected and not hydrolyzed does not attach to host cell membrane. Low levels of association of secondary phage DNA with membrane appear to be related to temporal genetic exclusion.

Inhibition of host deoxyribonucleic acid synthesis by T4 bacteriophage in the absence of protein synthesis

The requirement for phage protein synthesis for the inhibition of host deoxyribonucleic acid synthesis has been investigated by using a phage mutant unable to catalyze the production of any phage deoxyribonucleic acid. It has been concluded that the major pathway whereby phage inhibit host syntheses requires protein synthesis. The inhibition of host syntheses by phage ghosts is not affected by inhibitors of protein synthesis.

Metabolism of T4 bacteriophage ghost-infected cells: effect of bacteriophage and ghosts on the uptake of carbohydrates in Escherichia coli B

Ghosts of T4 bacteriophage inhibit the uptake of thiomethyl-beta-galactoside (TMG), alpha-methylglucoside, glucose-6-phosphate, and glycerol in Escherichia coli B. The transport of orthonitrophenyl-beta-galactoside (ONPG) is also inhibited to a lesser degree and without alteration of the apparent K(m) of transport. These effects of ghosts parallel those of energy poisons on these systems. However, no one energy poison can produce such pronounced inhibitory effects in all these systems. The effect of the intact phage in these systems was either absent or very slight relative to the ghost. The effect of ghosts on the uptake of TMG was not immediate; at 10 C, no effect of the ghosts was apparent for at least 2 min. This suggests that a step, more temperature dependent than the attachment of the ghost, is necessary for the inhibitory action. The intracellular level of adenosine triphosphate (ATP) in the ghost-infected cells fell to less than 25% of the control value, and the ATP lost from the cell appeared in extracellular medium. Phage, on the other hand, caused no decrease in the intracellular ATP level. This loss of ATP from the cells after ghost infection suggests an alteration of the barrier properties of the membrane so that ATP can leave the cell; however, the accessibility of extracellular ONPG to intracellular beta-galactosidase does not increase. The dissimilarity of the actions of phage and ghosts on all properties examined does not support the model that the initial events in their infections are identical but that the intact phage, unlike the ghost, can provide information for the repair of its effects.