TABLE 1.

Effect of heat treatment on P. fluorescens cell viability and GFP fluorescence^a

Cell treatment		GFP total cell concn (cells ml−1)b	G-mean for GFP total cellsc	PI-stained cell concn (cells ml−1)d	G-mean for PI+GFP cellse	% PI+GFP cellsh (PI-stained cells)	G-mean for GFP-PI cellsf	GFP increase for supernatantg
Temp (0°C)	Time
50	0 min	3.95 × 109	3.01	1.53 × 107	2.36	31.76	3.02	0
	5 min	2.76 × 109	2.09	1.56 × 108	2.01	29.25	2.07	743
	10 min	1.91 × 109	1.99	7.65 × 108	1.86	16.01	2.04	1,808
	15 min	1.16 × 109	1.86	1.96 × 109	1.67	10.37	1.95	3,268
	20 min	7.09 × 108	1.75	2.19 × 109	1.60	7.03	1.90	3,863
	30 min	5.01 × 108	1.65	2.52 × 109	1.57	6.33	1.84	4,140
39	0 h	1.65 × 109	3.38	8.75 × 106	2.48	47.51	3.41	0
	1 h	1.76 × 109	2.47	3.90 × 107	2.03	26.56	2.48	539
	2 h	1.76 × 109	2.46	4.70 × 107	2.00	22.75	2.50	667
	3 h	1.57 × 109	2.45	4.75 × 107	2.07	27.54	2.50	717
	4 h	1.81 × 109	2.45	5.14 × 107	2.07	24.59	2.50	839
	5 h	2.00 × 109	2.48	5.85 × 107	2.09	25.36	2.50	1,256

^aThe data are averages based on duplicate samples. 

^bConcentration of GFP fluorescent cells as determined by flow cytometry. 

^cGeometric mean fluorescence intensity of the cell population gated by flow cytometry. 

^dConcentration of PI-stained cells (dead cells) as determined by flow cytometry (dead cells). 

^ePI+GFP cells, GFP fluorescent cells gated by flow cytometry that were also stained with PI (dead fluorescent cells). 

^fGFP−PI cells, GFP-stained cells gated by flow cytometry that were not stained with PI (live fluorescent cells). 

^gRelative increase in GFP fluorescence intensity compared to an untreated control culture, expressed as a percentage. 

^hSee Table 1.