Table 2.
Detection of active prophage in D23580 by plaque formation on specific indicator strains for each D23580 prophage.
| Specific phage titer (PFU/mL) in D23580 WT supernatant |
|||
|---|---|---|---|
| Specific indicator strain | Target prophage | Non-induced | + Mitomycin C |
| D23580 ΔBTP1 | BTP1 | 1 × 109 | 2 × 1010 |
| D23580 ΔGifsy-2 galE496 | Gifsy-2 (BTP2) | Not detected | Not detected |
| D23580 ΔST64B | ST64B (BTP3) | Not detected | Not detected |
| D23580 ΔGifsy-1 galE496 | Gifsy-1 (BTP4) | Not detected | Not detected |
| D23580 ΔBTP5 | BTP5 | Not detected | Not detected |
| D23580 ΔGifsy-1 galE496 | Gifsy-1 PdinI-gfoA14028s | 1 × 104 | 2 × 106 |
| D23580 WT | Putative superimmune phage (control) | Not detected | Not detected |
| Specific phage titer (PFU/mL) in D23580 ΔBTP1 supernatant | |||
| D23580 ΔΦ (All five prophages deleted) | Gifsy-1, Gifsy-2, ST64B, or BTP5 | Not detected | Not detected |
‘Not detected’ indicates spontaneous phage induction at less than the detection threshold of 1 × 102 PFU/ml. D23580 was included as an indicator strain to confirm that the strain does not support plaques from induced phages present its own supernatant. To control for the possibility that other prophages may be super excluding the target phage in the specific indicator strains, supernatant from D23580 ΔBTP1 was plated on an indicator strain with all five prophages removed (D23580 ΔΦ), yielding no plaques.