TABLE 2.

Relative transformation frequencies, PO4 sensitivity, and twitching motility of P. stutzeri wild-type and pilT and pilU mutants

Straina	Plasmid	pil allele on chromosome		Presence of pil gene on plasmid		Relative transformation frequencyb	PO4 platingc	Twitching motilityd
		pilT+	pilU+	pilT+	pilU+
LO15	None	+	+	−	−	1	+	+
	pUCPpilT+	+	+	+	−	1.1 ± 0.3	+	+
	pUCPpilU+	+	+	−	+	1.3 ± 0.2	+	+
	pUCPpilT+U+	+	+	+	+	1.3 ± 0.3	+	+
Tf59	None	−	+	−	−	≤0.0003	−	−
	pUCPpilT+	−	+	+	−	0.8 ± 0.1	+	+
	pUCPpilU+	−	+	−	+	≤0.0008	−	−
	pUCPpilT+U+	−	+	+	+	0.9 ± 0.2	+	+
Tf591	None	+	−	−	−	0.1 ± 0.02	+	+
	pUCPpilU+	+	−	−	+	1.4 ± 0.3	+	+
	pUCPpilT+	+	−	+	−	0.1 ± 0.01	+	+
	pUCPpilT+U+	+	−	+	+	1.6 ± 0.2	+	+
	pKTpilU	+	−	−	+e	1.3 ± 0.2	+	+
Tf700	None	−	−	−	−	≤0.0003	−	−
	pUCPpilT+	−	−	+	−	0.06 ± 0.02	+	+
	pUCPpilU+	−	−	−	+	≤0.0005	−	−
	pUCPpilT+U+	−	−	+	+	0.9 ± 0.2	+	+

^aAs controls, the vectors pUCP19 and pKT240, corresponding to the plasmids with pilT or pilU genes, were electroporated into LO15, Tf59, Tf91, and Tf700. These strains gave transformation frequencies, PO4 plating results, and twitching motility similar to those of the corresponding strains without vector plasmid. 

^bTransformation frequencies were obtained by plate transformation and are expressed relative to the frequency in LO15 [(2 ± 0.2) × 10⁻⁵] using 1.5 μg of DNA per assay. Values are means of three experiments with standard deviations. 

^cPhage titer was 10⁸ ml⁻¹; 0.02 ml was spotted. +, confluent lysis of cells; −, no visible plaques. 

^d−, no twitching zones after 10 days at 37°C. 

^epilU⁺ of P. aeruginosa (42).