Table 2. Protein relative abundance ratios as signatures of cultivation conditions.

Ratio butyrate kinase: acetate kinase
ATCC strain number	Exponential	Stationary
3502	0.20	6.93
19397	0.20	2.17
17841	0.11	3.65
35415	0.13	6.30
3584	0.15	12.40
Ratio glycine reductase component B: 30S ribosomal subunit S13
ATCC strain number	Exponential	Stationary
3502	0.17	3.62
19397	0.18	6.64
17841	0.11	5.33
35415	0.14	7.70
3584	0.18	3.19

Relative protein abundances in cell fractions were used to calculate two proof-of-principle ratios to distinguish samples from early or late phase growth. Each ratio was calculated using two proteins that were identified in all samples and were consistently enriched in either exponential or stationary phase growth.