TABLE 2.

Relative cellular amounts of ATP and AcP in the parent D39 strain and SpxB-Pta-AckA pathway mutants growing exponentially in BHI broth

Straina	Presence of gene			Additionb
	spxB	pta	ackA		Relative amt (n)c
					ATPd	AcPe
IU1781	+	+	+	None	≡1 (9)	≡1 (8)
IU1781	+	+	+	15 mM potassium acetate	1.0 ± 0.05 (3)	1.6 ± 0.10 (2)
IU2173	−	+	+	None	1.0 ± 0.08 (3)	0.18 ± 0.02 (3)
IU2687	+	−	+	None	1.1 ± 0.06 (3)	1.0 ± 0.10 (3)
IU2687	+	−	+	15 mM potassium acetate	0.90 ± 0.08 (2)	1.5 ± 0.10 (2)
IU3590	−	+	−	None	0.53 ± 0.04 (3)	1.9 ± 0.20 (2)
IU2689	−	−	+	None	0.50 ± 0.05 (3)	0.08 ± 0.04 (3)
IU2837	−	−	−	None	0.54 ± 0.09 (3)	0.07 ± 0.01 (3)

^aFurther information on the indicated strains is provided in Table S1 of the supplemental material. The presence of capsule was confirmed by smooth colony formation on BA plates and Quellung reactions (see Materials and Methods).

^bPotassium acetate (CH₃CO₂K) was added to some cultures at a final concentration of 15 mM at the beginning of culture growth.

^cBacteria were grown to an OD₆₂₀ of 0.2, and relative cellular amounts of ATP and AcP were determined as described in Materials and Methods. The number of biological replicates (n) is indicated, and determinations were performed in duplicate within each replicate experiment.

^dThe amount of ATP recovered from 20 ml of encapsulated strain IU1781 (D39 cps⁺ rpsL1) cells at an OD₆₂₀ of 0.2 was 0.0067 μmol/mg of protein extract. This amount corresponds to an estimated cellular concentration of ≈2 mM ATP (see Materials and Methods). The experimental error of the ATP determinations was ≈8%.

^eThe amount of AcP recovered from 20 ml of IU1781 (D39 cps⁺ rpsL1) cells at an OD₆₂₀ of 0.2 was 0.011 μmol/mg of protein extract. This amount corresponds to an estimated cellular concentration of ≈3 mM AcP. The experimental error of the AcP determinations was ≈5%.