Exogenous 4-hydroxybenzoate can restore the quinone pool for cells bearing a ubiA(Q253P) mutation.

aBoth strains bore ΔflhB mutations.bFor exponential phase, cells were harvested at OD600 0.6.cFor cells in stationary phase, ubiquinone-8 (UQ-8) and menaquinone-8 (MK-8) were detected.dStandard deviations are shown for measurements performed in triplicate.a. 两株菌株均携带ΔflhB基因突变。 b. 对于指数生长期的细胞，于OD₆₀₀为0.6时收集菌体。 c. 对于稳定期细胞，可检测到泛醌-8（Ubiquinone-8, UQ-8）与甲基萘醌-8（Menaquinone-8, MK-8）。 d. 三次重复测量的结果均标注了标准差。