TABLE 3.

Levels of alginate production by P. aeruginosa algR strains

Strain	Genotype	Alginate pheno- typea	Alginate levelb
FRD1	Wild type	Alg+	1,905 ± 313
FRD831	ΔalgR::aacC1	Alg−	43 ± 2
FRD833	algR+ (by allele replacement)	Alg+	1,607 ± 157
FRD836	algR7 (AlgR.D54N)	Alg+	1,775 ± 157
FRD838	algR10 (AlgR.D85N)	Alg+	2,002 ± 240
FRD839	algR11 (AlgR.D54N.D85N)	Alg+	2,238 ± 324

^aAlginate phenotypes of P. aeruginosa strains containing the indicated algR alleles were scored as mucoid (Alg⁺) or nonmucoid (Alg⁻) after growth for 20 h on L agar plates. 

^bAlginate production in each strain was quantitated by the carbazole assay (26) with modifications described by Franklin et al. (19) and was expressed as micrograms per milliliter of total uronic acid. The results are means ± standard deviations for three independent experiments.