Expression of yhcS and/or ywpE in strain NDH31 (Δ yhcS and Δ ywpE ) from plasmids by Northern blot. (A, B) Schematic representation of chromosomal regions of the knockout strains SZ59, SZ60 and NDH30. The positions of ONs used for verification of the null alleles by PCR are indicated. Three pairs of primers have been used: ON54 and ON55 specifically recognize chromosomal DNA of strain SZ60 (1617-bp PCR product), ON56 and ON57 strain SZ59 (1486-bp PCR product) and ON57 and ON58 strain NDH30 (1602-bp PCR product). (C) Expression of yhcS and/or ywpE in strain NDH31 with different plasmids (pNDH33, pNDH33-yhcS, pNDH33-ywpE and pNDH33-ywpE-yhcS. Either a total of 0.25 μg (lanes 4, 6 and 8) or 5 μg of RNA (lanes 1, 2, 3, 5, 7) were loaded per lane. RNA markers are indicated on the right margin.