Mixed Infections of Bacillus subtilis Involving Bacteriophage SPO2c1

AUTOR(ES)
RESUMO

The synthesis of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) was studied in Bacillus subtilis cells mixedly infected with phages SPO2c1 and either SP82 or β22. It was found that cells preinfected 5 min with either β22 or SP82 could not support significant amounts of RNA or DNA synthesis from the genome of superinfecting SPO2c1. Conversely, cells preinfected with SPO2c1 remained susceptible to superinfection even at the midpoint of the latent period. When SP82 was added to cells preinfected 5 min with SPO2c1, the former greatly inhibited the replication and transcription of the SPO2c1, DNA, but if superinfection with SP82 was delayed until the 15th min of the SPO2c1 latent period, RNA and DNA specific for both phages were synthesized. Both viral genomes were transcribed throughout the remainder of the lytic cycle when β22 was added to cells preinfected either 5 or 15 min with SPO2c1. In both the SPO2c1-SP82 and the SPO2c1-β22 mixed infections, the types of phage-specific RNAs synthesized at a given time in the latent period were similar to those synthesized in single infections with each phage. The association of SPO2c1 DNA with the host cell membrane in certain of the doubly infected cells was different from that observed in singly infected cells. In the SPO2c1-SP82 infection, SPO2c1 DNA was not released from the membrane; in the SPO2c1-β22 mixed infections, significantly less SPO2c1 DNA was membrane-bound when β22 was added before SPO2c1. However, binding and release of SPO2c1 DNA was normal in cells infected first with SPO2c1 and then with β22. The synthesis of phage-specific nucleic acids and the binding of phage DNA to the membrane are discussed with respect to dominance relationships among these phages.

ACESSO AO ARTIGO

Documentos Relacionados