TABLE 2.

HPI transfer frequencies under various coculture conditions^a

Parameter tested	Amt or type	TfHPI (10−9)
Inoculumb	5 × 106	1.7
	5 × 107	1.0
	5 × 108	0.05
	5 × 109	0.04
Mediumc	LB broth	1.4
	LB broth + mitomycin C	3.0
	MH broth	2.0
	M63	3.1
	LB broth + α,α′-dipyridyl	11.1
	M63 + α,α′-dipyridyl	27.0
Tempd	4°C	8.8
	12°C	0.06

^aIP32637/do and IP32637/re were mixed in equal amounts in 25 ml of liquid medium and incubated for 4 days at 4°C (except when specified) with shaking.

^bEqual inocula of donor and recipient bacteria were grown in LB broth.

^cDonor and recipient bacteria (5 × 10⁷) were used.

^dDonor and recipient bacteria (5 × 10⁶) were cultured in LB broth plus α,α′-dipyridyl.