FIGURE 1.

GH20C expression. A, fold changes of GH20C transcript were measured by quantitative RT-PCR after exposure of TIGR4 to different carbohydrates. The fold change relative to expression levels when the bacterium was not exposed to sugar was calculated, and standard deviations of three replicates are indicated on each bar. B, production of GH20C protein by S. pneumoniae was detected by Western blotting using a polyclonal antibody raised against recombinant GH20C. Wild-type and Δgh20C mutant of S. pneumoniae TIGR4 were grown for 6 h at 37 °C in AGCH media and harvested by centrifugation. The cells were then lysed by sonication, and the culture supernatant and lysed cellular fractions were analyzed by Western blotting. Lane 1, recombinant GH20C; lane 2, TIGR4 wild-type supernatant; lane 3, Δgh20C mutant supernatant; lane 4, TIGR4 wild-type lysate; lane 5, Δgh20C mutant lysate.