FIG 2.

(A) 2D-TLC. AcP levels in acid extracts of cells that were labeled with [³²P]orthophosphate were monitored. Arrows, the position to which AcP migrates. Strains include the wild-type (WT) and ΔackA, Δpta, and Δpta ΔackA double mutant strains, as indicated by the labels. (B) Complementation of ackA and pta mutations. Accumulation of AcP in the wild-type and ΔackA mutant strains compared with that in the Δpta and ΔackA mutants in which the defective gene was complemented with a wild-type copy of pta (Δpta + com) or ackA (ΔackA + com). (C) Measurement of ATP. The wild-type, ΔackA, Δpta, and Δpta ΔackA strains were grown aerobically to early exponential phase in FMC medium, harvested, and resuspended in 250 μl cold buffer A (see details in Materials and Methods). Cells were lysed, and 50 μl of the lysates was reacted with an equal volume of the luminescent reagent. Luminescence intensity was measured using a Synergy 2 multimode microplate reader. The values shown are the means ± standard deviations for cell lysates from three separate cultures. *, the result differs significantly (P < 0.05, Student's t test) from that obtained in the wild-type genetic background. The results are expressed as means from triplicate assays for three independent isolates.