CASP1 and infection: In contrast to wild-type bacteria, both ΔBsaK and ΔFliCΔBsaK were not able to activate caspases-1, -9, -7 and to cleave PARP 1.5 hours after infection (Figure 9A), indicating that B. pseudomallei BsaK is required for early caspase-1 activation.