Table 3. Expression fold change of the yhiM-specific transcript in E. coli MG1655 in different conditions and mutant backgrounds as assessed by quantitative real time PCR.

Strain	MG1655				ΔgadX	ΔgadE
Medium	LB-MOPS pH 7.4			LB-MES pH 5.5
Condition	E-O2	E	S	S
Expr. fold	9	1	1.5	12.5	5.7	6
SEM	3		0.08	1.5	1.1	1.2
P value	0.0001		0.01	0.002	0.002	0.006

Total RNA was extracted from E. coli K12 strain MG1655 and its ΔgadX and ΔgadE derivatives grown to the exponential aerobic (E), exponential anerobic (E-O₂) and stationary (S) phases, in the indicated medium.