Fig. 4.

PGRP-SC1a catalytic activity is necessary to survive S. aureus infection. (A) Shown are survival curves comparing the responses of wild type, picky, catalytic rescue, and noncatalytic rescue flies with S. aureus infection. The catalytic rescue showed a significant increase in survival, as compared with picky mutants (P << 0.01), but remained below the survival levels of wild-type adults. The noncatalytic rescue did not show very significantly increased survival as compared with picky (P > 0.01). Injection of PBS in the two rescue lines was not significantly different from PBS injections in wild type and picky (all P >> 0.01) (data not shown). (B) picky mutants and the noncatalytic rescue flies are impaired in their ability to clear S. aureus–GFP bacteria from the hemocoel. The ability to collect S. aureus–GFP into blood cells corresponds with ability to survive infection. Shown are wild type at 12 h (the 24 h time point looks the same), picky at 12 h (the 24 h time point does not survive), and catalytic and noncatalytic rescue flies at 24 h after S. aureus-GFP infection.