TABLE 2.

Accumulation and activity of RsbT variants^a

rsbT allele	Accumulation and/or activity (%)
	E. coli	B. subtilis	Inducibility
Wild type	+	+	+
T1	+	+	+
T2	+	± (38%)	+
T3	+	± (51%)	−
T4	+	+	−
T5	+	+	−
T6	+	+	+
T7	+	+	−
T8	+	± (20%)	−
T9	+	+	+
T10	+	± (24%)	+
T11	+	± (42%)	+
T12	+	+	+
T13	+	± (34%)	−
T14	−	−	−
T15	+	−	−
T16	+	+	−
T17	−	−	−
T18	+	−	−

^aThe columns represent detection by Western blotting of the various rsbT products in E. coli and B. subtilis and their abilities to activate σ^B after ethanol treatment. For E. coli, “+” represents a detectable product regardless of level, and “−” represents undetectable RsbT. For B. subtilis, quantitation of the Western blots was performed with an Alpha Imager 2000 and its associated software. RsbT variants that accumulated at levels approximating that of wild-type RsbT are designated “+”; those displaying background signal levels are designated “−” and those with intermediate accumulation of RsbT are depicted as “±,” along with their relative abundances as a percentage of the wild-type RsbT levels. A “+” in the inducibility column reflects the ability of B. subtilis carrying the particular rsbT allele to display σ^B induction (5- to 10-fold increase in σ^B-dependent reporter gene activity) by 15 min after ethanol addition. The “−” strains displayed no difference in the activities of treated and untreated cultures.