Homology between Phages SPP1, 41c, 22a,  15 and SF6 of Bacillus subtilis

Abstract

SUMMARYBacteriophages SPP 1, 4 lc, 22a, p 15 and SF6 of Bacillus subtilis share a common and specific host receptor site for adsorption. Experiments described here have established the relatedness between these phages. They were indistinguishable on the basis of hostrange, plating efficiency, various growth parameters and serological properties. In addition, they shared the ability to carry out generalized transduction. They could be differentiated, however, by the restriction patterns of their DNAs, with the exception of 41c and 22a, which seemed to be identical. Recombination between 41c and SPP1 was demonstrated by transfection with mixed digests of their DNAs.A mutation conferring resistance to infection by bacteriophage SPP1 (pha-2) was recently mapped in the chromosome of Bacillus subtilis 168 (Santos et al., 1983). Out often other bacteriophages tested, only 41c, 22a, pl 5 and SF6 failed to infect pha-2 strains. Although these phages share some morphological characteristics with SPP 1, until now no evidence has been presented as to their possible relatedness. In order to clarify the specificity of the pha-2 mutation, a comparative study of these five phages was undertaken. SP01, a phage unrelated to SPP1 (Hemphill & Whiteley, 1975), was included as a control.Bacterial strains used are listed in (Okubo et al., 1964) were propagated on B. subtilis 168T + as described previously (Santos et al., 1983).Lysates were treated with 100 gg/ml DNase I at 37 °C for 30 min, before use in transduction experiments.M broth and M soft agar (Santos et al., 1983) were used for growth of bacteria, preparation of phage lysates and plating. SPP1, 41c, 22a, p15 and SF6 exhibit the same plaque morphology. They all form large, clear plaques, sometimes surrounded by a turbid halo, when plated on an appropriate strain. The Origin/reference

Bacteriophage Infection in Rod-Shaped Gram-Positive Bacteria: Evidence for a Preferential Polar Route for Phage SPP1 Entry in Bacillus subtilis

“…SPP1 phages were produced in B. subtilis YB886 (51) grown in LB medium and supplemented with 10 mM CaCl 2 just before infection (38). Isolated phage plaques (10 5 to 10 6 PFU) were used to generate confluent plate lysates (10 8 to 5 ϫ 10 8 PFU), and then the phages were amplified sequentially in small-and large-scale culture infections.…”

Bacillus subtilisOperon Encoding a Membrane Receptor for Bacteriophage SPP1

“…pha-2 mutants retained the capacity to adsorb phages at a wild-type rate, but phage-host complexes could be readily separated by dilution, showing the process to be wholly reversible. The mutation was found to be specific for SPP1 and related phages and was mapped, by PBS1-mediated transduction, in the vicinity of the ald-1 marker (29,30).…”

“…pha-2 mutants retained the capacity to adsorb phages at a wild-type rate, but phage-host complexes could be readily separated by dilution, showing the process to be wholly reversible. The mutation was found to be specific for SPP1 and related phages and was mapped, by PBS1-mediated transduction, in the vicinity of the ald-1 marker (29,30).Based on the map position of the pha-2 locus and the availability of the complete sequence of the B. subtilis genome, we have now attempted to identify the gene required for SPP1 irreversible adsorption. The experiments described here identify yueB, an orthologue of pip, as the key gene involved in irreversible adsorption of SPP1.…”

The SPP1 connection

“…Quantitative analysis showed that an average of approximately 130000 copies of portal monomers are present per infected cell (30 min). This value represents a large excess relatively to the theoretical amount of gp6 required to accomplish its structural role in the virion if we take into consideration the SPP1 burst size (260-560 infectious particles/cell depending on the experimental conditions [30]) and assume that the portal protein is also a 13-met in the phage particle [1]. The meaning of such high production of gp6 in infected cells is not yet understood.…”