The process of infection with bacteriophage φX174. XVIII. Intracellular Antiserum-precipitable Components

Components precipitable by antiserum to bacteriophage φX174 can be derived from φX-infected cells. Antiserum-precipitable ^(35)S is found in three peaks after zone sedimentation in sucrose gradients. The fastest sedimenting peak is infective virus; the intermediate peak is the non-infective 70 s component. The slowest component was studied in greater detail and has the following properties. It has a sedimentation coefficient of about 6; in a thymine-requiring host, the material accumulates in the absence of thymidine; the accumulated material is subsequently incorporated into virus when thymidine is restored. The 6 s material is, therefore, considered to be a subunit of the virus structure. The φX double mutant am3tsγ, which does not make whole virus under restrictive conditions, forms a subunit which appears to have similar sedimentation properties to that of the wild type

The process of infection with bacteriophage φX174. XVIII. Intracellular Antiserum-precipitable Components

Components precipitable by antiserum to bacteriophage φX174 can be derived from φX-infected cells. Antiserum-precipitable ^(35)S is found in three peaks after zone sedimentation in sucrose gradients. The fastest sedimenting peak is infective virus; the intermediate peak is the non-infective 70 s component. The slowest component was studied in greater detail and has the following properties. It has a sedimentation coefficient of about 6; in a thymine-requiring host, the material accumulates in the absence of thymidine; the accumulated material is subsequently incorporated into virus when thymidine is restored. The 6 s material is, therefore, considered to be a subunit of the virus structure. The φX double mutant am3tsγ, which does not make whole virus under restrictive conditions, forms a subunit which appears to have similar sedimentation properties to that of the wild type

The Process of Infection with Bacteriophage φX174: XVII. Effects of Specific Metabolic Interruptions

The effects of metabolic interruptions on the infective process of bacteriophage φX174 in Escherichia coli THU (a derivative of E. coli 15, requiring thymine, histidine and uracil) have been studied. The experiments indicate that: 1.(1) the synthesis of a histidine-containing protein is necessary for the replication of the parental replicative form φX DNA; 2.(2) the continued synthesis of viral DNA is necessary to maintain a normal rate of synthesis of antiserum-precipitable viral protein; in the absence of thymidine the rate of synthesis of this protein falls off progressively; and 3.(3) there appears to be a requirement for concomitant protein and DNA synthesis to produce mature virus particles. The nature of the concomitant protein requirement is not known although it does not appear to be the anti-serum-precipitable protein

The Process of Infection with Bacteriophage φX174: XVII. Effects of Specific Metabolic Interruptions

The effects of metabolic interruptions on the infective process of bacteriophage φX174 in Escherichia coli THU (a derivative of E. coli 15, requiring thymine, histidine and uracil) have been studied. The experiments indicate that: 1.(1) the synthesis of a histidine-containing protein is necessary for the replication of the parental replicative form φX DNA; 2.(2) the continued synthesis of viral DNA is necessary to maintain a normal rate of synthesis of antiserum-precipitable viral protein; in the absence of thymidine the rate of synthesis of this protein falls off progressively; and 3.(3) there appears to be a requirement for concomitant protein and DNA synthesis to produce mature virus particles. The nature of the concomitant protein requirement is not known although it does not appear to be the anti-serum-precipitable protein