TABLE 2.

Effects of glycine concentration, cell density when glycine is added, concentration factor of cells, and MgCl₂ concentration in EPB on the transformation efficiency of S. salivarius ATCC 25975 with pNZ123^a

Glycine concnb	OD660c	Cell concn factord	pHe	MgCl2 concnf	Transformants/μg
+	−	+	+	−	1.78 × 104
−	−	−	+	+	1.03 × 104
+	−	−	−	+	6.29 × 104
−	−	+	−	−	Lg
−	+	+	−	+	2.00 × 103
+	+	−	−	−	7.95 × 104
−	+	−	+	−	1.83 × 104
+	+	+	+	+	9.25 × 103
0	0	0	0	0	3.99 × 104
0	0	0	0	0	3.00 × 104
0	0	0	0	0	2.01 × 104

^aCells were grown in HJGS. Glycine was added to cultures at different OD₆₆₀, and the cultures were incubated for an additional 2 h. 

^b−, 2.5% glycine; 0, 5% glycine; +, 10% glycine. 

^c−, OD₆₆₀ = 0.4; 0, OD₆₆₀ = 0.6; +, OD₆₆₀ = 0.8. 

^d−, 40; 0, 60; +, 80. 

^e−, pH 4.5; 0, pH 5.0; +, pH 5.5. 

^f−, no MgCl₂; 0, 2 mM MgCl₂; +, 4 mM MgCl₂. 

^gL, the culture was lost.