SIRT3 and infection: Furthermore, we found that the SIRT3 transcript levels increased from 12 h p.i. (P<0.01) with the rise becoming more significant later in the infection (P<0.01; P<0.001) (Figure 2A, B), while SIRT4 transcript levels increased at 12 h p.i. (P<0.01) and remained constant at this higher level until the end of infection (Figure 2A, C).