FQE increases CpsD-P in S. pneumoniae D39.

S. pneumoniae D39 were grown to mid log phase in THY (OD₆₀₀ ≈ 0.35) and FQE at indicated concentrations were added. (A) These concentrations (µM) had no statistically significant effect on CFU/ml after 30, 60 and 120 mins. (B) Whole cell lysates were prepared from these cells, which were separated by SDS-PAGE and analyzed by immunoblotting using anti-CpsD, or anti-phosphotyrosine (to detect CpsD-P). (C) Densitometric analysis of CpsD-P from three separate experiments. The effect with addition of 5 µM was significantly higher than compared with 1.25 µM FQE (* - P<0.05 by Student’s t-test). (D) For comparison, the effect of an in-frame cpsB deletion mutant on CpsD-P is shown.