PARP1 and infection: As shown in Fig. 2F, TNF-α plus cycloheximide (CHX) treatment triggered autocleavage of caspase-8 as well as its cleavages of Bid, caspase-3, caspase-7, and PARP1, all of which was blocked by infection with CopC-positive C. violaceum but not ΔcopC strain.