TABLE 3.

Relative photoreactivation and plating efficiency factors for four bacteriophages on physiologically distinct P. aeruginosa PAO303 hosts incubated in the light

Phage	Photoreactivation factors for UV-C-irradiated phage with the following hostsa:					Plating factors for unirradiated phage with the following hostsa:
	Exponential phase	Stationary phase	Starved for 24 h	Starved for 1 week	Starved for 5 weeksb	Exponential phase	Stationary phase	Starved for 24 h	Starved for 1 week	Starved for 5 weeksb
D3C3	9.07 (0.32)c	8.97 (0.03)c	8.35 (2.33)c	7.72 (1.46)c	7.95 (0.20)c	0.87 (0.06)c	1.13 (0.12)	0.99 (0.07)	0.92 (0.04)c	0.87 (0.08)
F116	15.74 (6.64)c	11.32 (2.06)c	13.27 (3.83)c	12.47 (1.43)c	5.52 (2.83)	0.95 (0.36)	1.00 (0.15)	0.97 (0.06)	1.26 (0.39)	0.99 (0.11)
G101	10.76 (1.44)c	16.01 (5.45)c	13.34 (0.97)c	13.72 (2.37)c	10.07 (1.75)c	0.96 (0.15)	1.07 (0.06)	1.14 (0.34)	0.86 (0.08)	1.12 (0.17)
UNL-1	5.81  (0.64)c	5.74  (2.26)c	7.92  (4.17)	4.88  (0.28)c	6.69 (0.54)c	0.86 (0.15)	0.88 (0.09)	0.71 (0.04)	1.05 (0.17)	0.93 (0.01)c

^aThe factors were each calculated by comparing the plating (plaque-forming) efficiency obtained on plates incubated in the light, where photoreactivation was possible, to the plating (plaque-forming) efficiency of the same phage sample on the same type of host cells incubated in the dark, where photoreactivation was not possible. For example, the stationary-phase factor was the ratio of the number of PFU on stationary-phase cells incubated in the light to the number of PFU obtained on stationary-phase cells incubated in the dark. All experiments with a given phage type were conducted by using duplicate plate assays, with two to four separate trials conducted on different days. The standard errors are in parentheses. 

^bAll data for the cells starved for 5 weeks were obtained by using bacteriophages which had been UV-C inactivated within 36 h of the experiment. 

^cThe z values were significantly different (P < 0.05) from the control values.