. 2014 Aug 6;5:404. doi: 10.3389/fmicb.2014.00404

Table 5.

Effect of nitrite and O₂ on levels of specific transcripts of S. wittichii RW1 from mid-log and early stationary phase cultures.

mRNA	WT (atmospheric O₂)				WT (reduced O₂)				norZ_ch (atmospheric O₂)
	0.3 mM		1.0 mM		0.3 mM		1.0 mM		0.3 mM		1.0 mM
	24 h	36 h	24 h	36 h	20 h	24 h	20 h	24 h	24 h	36 h	24 h	36 h
nirK	1.68^a	1.56^a	3.98^a	2.17^a ^b	0.89^a	0.96	2.00^a	1.38	1.81^a	2.28^a	4.53^a	1.56^a ^b
hmp	1.23	2.20	1.24^b	2.52	1.26^a	1.47^a	3.89^a	2.65^a	1.18^a	2.28	2.00^a ^b	2.79
norZ_ch	1.37^b	1.51^a ^b	1.42^b	1.00^a ^b	0.80	0.93	1.15	1.14	Not expressed in this strain
norZ_p	0.88^b	0.88^b	0.89^b	0.91^b	1.09	1.31	1.63	1.69	1.39^a ^b	1.70^b	2.21^a ^b	1.58^b

Values represent the ratio of hybridization intensity between nitrite-treated and untreated cells, previously normalized to 16S rRNA levels, and averaged from 5 experiments initiated on separate cultures on separate days. Bold values indicate a two-fold or greater increase in transcript level between NaNO₂-treated and untreated cells. Statistically significant differences between treatments were determined by Student's t-test at p < 0.05 and are designated as follows:

Significant difference between 0.3 and 1 mM NaNO₂ treatment groups of wild-type (WT) or norZ_ch mutant cultures of S. wittichii RW1 at the same time point.

Significant difference between WT and norZ_ch mutant cultures initiated at atmospheric O₂, incubated with 0.3 or 1 mM NaNO₂.