CHANGES IN HOST-CELL ENERGETICS IN RESPONSE TO BACTERIOPHAGE-PRD1 DNAENTRY

Double-stranded DNA bacteriophage PRD1 infects a variety of gram-negat ive bacteria harboring an IncP-type conjugative plasmid. The plasmid c odes for the DNA transfer phage receptor complex in the cell envelope. Our goal was, by using a collection of mutant phage particles for whi ch the variables are the DNA content and/or the presence of the recept or-binding protein, to obtain information on the energy requirements f or DNA entry as well as on alterations in the cellular energetics taki ng place during the first stages of infection. We studied the fluxes o f tetraphenylphosphonium (TPP+), phenyldicarbaundecaborane (PCB-), and K+ ions as web as ATP through the envelope of Salmoneila typhimurium cells. The final level of the membrane voltage (Delta Psi) indicator T PP+ accumulated by the infected cells exceeds the initial level before the infection. Besides the effects on TPP+ accumulation, PRD1 induces the leakage of ATP and K+ from the cytosol. AII these events were ind uced only by DNA-containing infectious particles and were cellular ATP and Delta Psi dependent. PRD1-caused changes in Delta Psi and in PCB- binding differ considerably from those observed in other bacteriophag e infections studied. These results are in accordance with the presenc e of a specific channel engaged in phage PRD1 DNA transport.