FIG 7.

RNase Y affects the Sec secretion system. (A) rny conditional knockdown strains or HN13 were cultured with or without 1 mM lactose to mid-exponential phase at 37°C. Total RNA was isolated prior to or after the addition of rifampin (200 μg ml⁻¹). In each lane, 2 μg of total RNA was loaded and hybridized with secA-, ffh-, and cwlO-specific probes. The lengths of the detected transcripts are indicated in kilobases on the right. 16S rRNA stained with methylene blue on the blots is indicated at the bottom as a loading control. (B) Extracellular protein expression in HN13 or rny conditional knockdown strains. Extracellular proteins equivalent to 0.04 OD₆₀₀ units were prepared from the supernatant of the culture grown for 6 h at 37°C and were loaded in each lane. Arrows indicate CwlO proteins estimated based on molecular size.