TABLE 1.

Effects of media and buffers on bactericidal activities of DAPs against S. aureus ATCC 29213 and P. aeruginosa ATCC 27853

Medium or buffer	mosM	pH	Peptide treatment (concn [μM])a	% Organisms killed at indicated incubation times:
				S. aureus				P. aeruginosa
				30 min	1 h	2 h	4 h	30 min	1 h	2 h	4 h
Media
TSB	324	7.2	D2A21 (1)	0	0	4.6	1.7	20	34	40.6	74.7
			D2A21 (5)	25.8	25	39.8	40	30.4	66	100b	100
			D4E1 (1)	0	3.6	0.8	10.9	0	0	1.9	16.4
			D4E1 (5)	2.3	4.2	5.3	15.8	20	56.4	75.1	54.9
NB plus 125 mM NaCl	290	7.2	D2A21 (1)	13.7	16	35.9	56.3	78.5	71.1	72.8	87
			D2A21 (5)	31.1	36	52.8	73.6	100	100	100	100
			D4E1 (1)	0	3.1	7	7.1	57.8	51.4	43.4	50
			D4E1 (5)	38.5	42.6	56.1	46.1	100	100	100	100
adjMHB	285	7.2	D2A21 (1)	1.7	11.4	3.9	0.3	17.4	19.4	19.2	18.2
			D2A21 (5)	37.3	50.4	60.4	73.1	85.4	100	100	100
			D4E1 (1)	3.7	5.4	6.2	12.1	1.5	2	11.1	11
			D4E1 (5)	6.7	12.2	22.2	44	36.1	50.6	60.2	60.7
MHB	297	7.2	D2A21 (1)	14.6	16.7	23.5	43.1	89.6	89.8	84	71.4
			D2A21 (5)	47.9	52.1	74.5	77.6	100	100	100	100
			D4E1 (1)	10.4	16.7	7.8	19	12.2	18.1	35.3	48.5
			D4E1 (5)	43.8	45.8	68.6	86.2	29.9	28.8	53.1	73.2
Modified RPMI	285	7.2	D2A21 (1)	30.5	43.3	62.4	100	100	100	100	100
			D2A21 (5)	84.9	85.2	100	100	100	100	100	100
			D4E1 (1)	9.7	9.7	11.9	19	46.4	29.5	42.6	50.3
			D4E1 (5)	49.7	75.4	100	100	68.1	100	100	100
Buffers
PBS	312	7.2	D2A21 (1)	4.7	9.3	12.6	37.5	100	100	100	100
			D2A21 (5)	26.3	34.4	64	100	100	100	100	100
			D4E1 (1)	1.1	0	11.8	74.8	46.6	57.6	70.7	71.9
			D4E1 (5)	9	11.1	83.6	100	100	100	100	100
Tris-NaCl buffer	276	7.2	D2A21 (1)	89.2	75.6	100	100	100	100	100	100
			D2A21 (5)	100	100	100	100	100	100	100	100
			D4E1 (1)	11.4	19	30.7	41.6	6.9	40.7	50.7	55.4
			D4E1 (5)	83.4	100	100	100	43.3	100	100	100
Tris-NaCl buffer	285	8.4	D2A21 (1)	100	100	100	100	100	100	100	100
			D2A21 (5)	100	100	100	100	100	100	100	100
			D4E1 (1)	100	100	100	100	100	100	100	100
			D4E1 (5)	100	100	100	100	100	100	100	100
Citrate-phosphate buffer	309	7	D2A21 (1)	28.3	31	36.1	47.1	82.3	100	100	100
			D2A21 (5)	26.1	77.6	100	100	100	100	100	100
			D4E1 (1)	6.9	8.8	10.4	22.7	46.4	61.9	63.3	59.6
			D4E1 (5)	54.3	59.5	62.2	65.2	63.3	69.7	70	85.3
Citrate-phosphate buffer	298	5	D2A21 (1)	5.2	2.3	1.3	23.1	86.8	100	100	100
			D2A21 (5)	20.1	19.3	15.8	23.1	100	100	100	100
			D4E1 (1)	5.9	3.8	1.1	22.7	100	100	100	100
			D4E1 (5)	88.7	100	100	100	100	100	100	100
Saline	281	5.6	D2A21 (1)	30.5	32.5	42.3	57.7	100	100	100	100
			D2A21 (5)	71.2	62	62.3	79.8	100	100	100	100
			D4E1 (1)	13.1	59.8	100	100	17	34.8	57.1	79.6
			D4E1 (5)	100	100	100	100	57.4	67.4	83.7	100
Phosphate buffer	309	7.2	D2A21 (1)	10.8	10	16.5	15.4	100	100	100	100
			D2A21 (5)	28.7	52	41.6	67.7	100	100	100	100
			D4E1 (1)	0	0	1.4	0	39.1	38.8	39.8	63.6
			D4E1 (5)	12.4	18.3	32.9	42.5	74.2	100	100	100

^aConcentrations of 1 and 5 μM D2A21 correspond to 4.3 and 21.5 μg/ml, respectively, and concentrations of 1 and 5 μM D4E1 correspond to 2.8 and 14 μg/ml, respectively. 

^bKilling of ≥99.9% of the final inoculum was defined as 100%.