Table I. Bacterial strains and plasmids used in this study.

Strain/plasmid	Genotype or phenotype	Reference
E.coli
ET8000	rbs lacZ::IS gyrA hutCK	Jayakumar et al. (1986)
AT8000	rbs lacZ::IS gyrA hutCK ΔglnB1, ΔamtB	Reyes-Ramirez et al. (2001)
FT8000	rbs lacZ::IS gyrA hutCK ΔglnB1, ΔglnK1	Reyes-Ramirez et al. (2001)
GT1000	rbs lacZ::IS gyrA hutCK ΔglnKamtB	this work
GT1001	rbs lacZ::IS gyrA hutCK ΔamtB	Thomas et al. (2000b)
GT1002	rbs lacZ::IS gyrA hutCK ΔglnK1	this work
PT8000	rbs lacZ::IS gyrA hutCK ΔglnB1	Reyes-Ramirez et al. (2001)
RB9060	ΔlacU169 endA1 thi-1 hsdR17 supE44 hutCK ΔglnB2306	Bueno et al. (1985)
WCH30	ΔlacU169 endA1 thi-1 hsdR17 supE44 hutCK ΩGmr ΔglnK1	Arcondéguy et al. (1999)
YMC10	ΔlacU169 endA1 thi-1 hsdR17 supE44 hutCK	Chen et al. (1982)
A.vinelandii
UW136	Rifr	Bishop and Brill (1977)
MV560	Rifr ΔamtB1::KIXX	Meletzus et al. (1998)
Plasmids
pGC2	glnK amtB1 in pACYC184	this work
pGC4	glnK amtB4 in pACYC184	this work
pGT11	glnK amtB in pWSK29	this work
pGT14	amtB in pWSK29	Thomas et al. (2000b)
pMM280	glnK amtB3 in pACYC184	this work
pTA40	glnK in pWSK30	this work
pTA43	glnKY51F in pWSK30	this work