FIG. 6.
Plots of relative levels of transcription of B. breve 210B, B. longum subsp. infantis ATCC 15697, B. longum subsp. longum ATCC 15707, and B. dentium Bd1 serpin-encoding genes after serine protease treatment versus growth in MRS-based media as analyzed by quantitative real-time PCR assays (a) and by slot blot hybridization (b). The bars indicate the relative amounts of ser mRNAs for the specific samples. The cDNAs used were synthesized using RNA collected from bifidobacterial cultures exposed for 150 min to α-chymotrypsin (αCH), chymotrypsin (CHY), neutrophil elastase (HNE), kallikrein (KAK), pancreatic elastase (PPE), papain (PAP), plasmin (PLA), trypsin (TRY), or thrombin (TRO). For panel b, induction of the ser210B gene was evaluated by slot blot hybridization. Total RNA (25 μg per slot) was isolated from B. breve 210B cells exposed for up to 150 min to different serine proteases (see above) and probed with biotin-labeled ser. The resulting hybridization signals obtained in the autoradiograms were quantified. The amount of mRNA synthesized under the conditions described above was normalized to the amount present in cultures grown in MRS medium.