The Fine Structure of Bacteriophages

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SUMMARYThe electron microscope shows that there are a number of different morphological types of bacteriophages which grow on Pseudomonas aeruginosa. Some are conventional ones with contractile or non-contractile tails, but the most interesting is a tail-less phage containing RNA. The structure of both conventional and RNA phages is described. It is shown that the RNA phage probably infects the cell via polar pili. Intracellular multiplication and lysis by the RNA phage is followed in thin sections of infected cells. In the early stages, the nuclear region is much reduced and dense granular areas appear. These subsequently differentiate into crystalline aggregates of virus particles; at the same time a large bulge, identical to that found associated with spheroplast formation, appears. The crystals continue to increase in size until the spheroplast ruptures and lysis occurs.

Section: Phages With Non-contractile Tailsmentioning

confidence: 99%

The Structure and Infective Process of a Pseudomonas Aeruginosa Bacteriophage Containing Ribonucleic Acid

Bradley

1966

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“…Recent work (Brock & Wooley, 1963) using high-speed blending has confirmed that streptomycin inhibits injection. Bradley & Kay (1960) have studied the morphology of a variety of bacteriophages, using the phosphotungstic acid negative-staining technique. They have shown that the long-tailed phages fall into two groups.…”

Section: Adamsmentioning

confidence: 99%

The Inhibition by Streptomycin of Certain Streptococcus Bacteriophages, using Host Bacteria Resistant to the Antibiotic

Brock

Mosser

Peacher

1963

SUMMARYStreptomycin is a specific antiviral agent for a variety of bacteriophages active against Streptococcus faecium, S . faecalis, S . liguefaciens and S . xymogenes since it inhibits bacteriophage growth even when the host is resistant to the antibiotic. An analysis of the mode of action of the antibiotic in this system reveals that it probably has two effects. If the antibiotic is present before adsorption, it inhibits injection of the phage DNA. This effect is readily reversible. If the antibiotic is added after adsorption, it appears that injection is not inhibited, but that the phage genome is inactivated. The antibiotic has no effect on replication of the phage once the genome has become established in the host cell. This is consistent with the hypothesis that the phage DNA exists transiently a t a streptomycin-accessible site, and then moves to a site of replication which is inaccessible to the antibiotic. Streptomycin-resistant phages probably have a different injection mechanism from streptomycin-sensitive phages.The senior author has reported similar findings for an RNA bacteriophage of Escherichia coli. The implications of this work for virus chemotherapy and for analysing the mode of penetration into the cell of virus nucleic acid are discussed.

“…The phages were prepared for examination in the electron microscope by the conventional shadowcasting procedure and by the negative contrast method of Brenner et al (1959). Measurements on phages Ox-1 and Ox-6 (then named 11F and 66F) were given by Bradley & Kay (1960). The other phages have not been so accurately measured but have been judged solely on their overall appearance.…”

Section: Methodsmentioning

confidence: 99%

Hydroxymethylcytosine-containing and Tryptophandependent Bacteriophages Isolated from City Effluents

Kay¹,

Fildes²

1962

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