FIG. 2.

Triggering of the autolysin LytA by miltefosine and effect of hydrophobic tail length on pneumococcal lysis. (A) An exponentially growing culture of S. pneumoniae strain M32 (ΔlytA32) was incubated in C medium-0.08% yeast extract with (open symbols) or without (solid symbols) the pure LytA enzyme (10 μg/ml) for 1 h at 37°C. The culture was then diluted to an A₅₅₀ of 0.2 and divided into two portions. Miltefosine was added at 25 μM (⋄, ♦) to one portion, and the other portion was left untreated (○, •). Incubation was continued at 37°C. Survival of the culture treated only with miltefosine was determined by plating at different incubation times (dotted lines). (B) Growth (and lysis) curves of the pneumococcal R6 strain treated with miltefosine (⋄), tetradecylphosphocholine (□), or dodecylphosphocholine (▵); each drug was added at a final concentration of 25 μM. The growth curve of an untreated R6 culture is indicated by solid circles.