Transfection of non-host bacterial spheroplasts with bacteriophage ΦX174 DNA

Abstract

BACTERIOPHAGE ΦX174 containing circular single-stranded DNA (SS-DNA) can infect Escherichia coli C and Shigella^1–4 Progeny phages are produced through synthesis of circular double-stranded DNA (replicative form, RF-DNA) as the intermediate^5,6. ΦX174 cannot infect bacteria which have no specific receptors for phage adsorption on the cell wall. The host range in ΦX infection is thought to be determined primarily by success or failure of adsorption and if most of the cell wall is removed from the bacterium, the host range is extended and ΦX-DNA can infect E. coli strains other than the host, and produce progeny phages. But if the recipient bacterial spheroplasts are of species distantly related to the host, ΦX-DNA may not be able to penetrate into the spheroplasts and replicate and produce progeny phages as well as in the host spheroplast. It is known that ΦX phage replication in E. coli depends largely on host functions; for example, the ΦX-DNA replication is greatly affected by several genes responsible for host DNA synthesis^7,8. On this basis, ΦX-DNA replication in bacteria distantly related to the natural host might on the one hand fail because of incompatibilities between ΦX-DNA and bacterial gene functions or on the other hand be successful because common gene functions are widespread throughout a wide range of bacterial species. We tried to transfect ΦX-DNA to various bacteria belonging to the Enterobacteriaceae, and Pseudomonas aeruginosa to examine the capability for phage production in bacteria other than the host, and found that ΦX-RF-DNA synthesis proceeded as efficiently as in the natural host in distantly related species of bacteria, but that progeny phage production was greatly reduced. Bacterial relationships determined on the basis of DNA homology.