TABLE 3.

Complementation of actA and hly at the comK phage attachment site

StrainGenotypeHemolysis on blood platesHemolytic activitya (U)Plaque sizeb % of wt (SD)LD50c (CFU)
10403SWild type+nd100 (na)∼2 × 104
DP-L405610403S phage cured+97101 (1.4)<1 × 105
DP-L4074DP-L4056 comK::pPL1+9899 (1.4)<1 × 105
DP-L4027DP-L2161 phage cured, Δhly00 (0)1 × 109d
DP-L4075DP-L4027 Δhly comK::pPL24+9997 (3.9)<1 × 105
DP-L4076DP-L4056 comK::pPL24+19896 (2)nd
DP-L4029DP-L3078 phage cured, ΔactAndnd0 (0)2 × 107d
DP-L4077DP-L4029 ΔactA comK::pPL25ndnd86 (4)<1 × 105
DP-L4078DP-L4056 comK::pPL25ndnd72 (6.8)nd
  • a Hemolytic activity data shown are from one representative experiment. nd, not determined.

  • b Plaque size is the average of 8 to 10 independent experiments and shown as a percentage of wild-type (wt) size (defined as 100%). Standard deviations are shown in parentheses. na, not applicable.

  • c LD50s of 10403S and an hly mutant were determined previously (40) (the Δhly strain DP-L2161 was described previously [22]), and the LD50 of the ΔactA strain (DP-L1942, a smaller deletion within the actA open reading frame that does not support actin nucleation at the bacterial surface) was also determined previously (4).

  • d LD50 data shown are for the non-phage-cured deletion strains (i.e., DP-L2161 and DP-L1942) and not for the phage-cured strains (i.e., DP-4027 and DP-L4029).