TABLE 1.

Bacterial strains and plasmids

Strain or plasmid	Genotype	Resistancea	Source
Escherichia coli strains
CV1	Chemotaxis wild type (same as RP437)	Str	24
TG1/pDS-Red Express	Wild type; dead-cell control	Amp	Stratagene
CV5	CV1 Δtsr	Str	This studyb
CV12	CV1 Δtar-tap trg::Tn10	Str, Tet	This studyc
MJ101	CV1 lsrBΩKanr	Str, Kan	This studyd
MJ102	CV1 lsrCΩKanr	Str, Kan	This studye
BW25113 ΔlsrB	lsrBΩKanr	Kan	3
BW25113 ΔlsrC	lsrCΩKanr	Kan	3
Plasmids
pCM18	GFP-expressing vector	Erm	12
pDS-RedExpress	RFP-expressing vector	Amp	Clontech
pCA24N-lsrB	pCA24N PT5-lac::lsrB; expresses E. coli lsrB from placZYA	Cm	15

^aStr, streptomycin; Tet, tetracycline; Kan, kanamycin; Erm, erythromycin; Amp, ampicillin; Cm, chloramphenicol.

^bMade by introducing Δtsr9101 (7) into CV1 by phage P1 transduction (16), with selection for Thr⁺ and screening for Tsr⁻.

^cMade in two steps: Δtar-tap5201 (26) was introduced into CV1 by phage P1 transduction with selection for Eda⁺, followed by screening for Tar⁻, and then trg::Tn10 was introduced by phage P1 transduction followed by selection for Tet^r on lysis broth (LB) (20) agar plates containing 10 μg/ml tetracycline, followed by screening for Trg⁻.

^dMade by introducing lsrBΩKan^r (3) into CV1 by phage P1 transduction, with selection for Kan^r and confirmation of lsrB gene disruption by PCR.

^eMade by introducing lsrCΩKan^r (3) into CV1 by phage P1 transduction, with selection for Kan^r and confirmation of lsrC gene disruption by PCR.