TABLE 4.

Summary of incompatibility testing^a

Incoming plasmid	Resident plasmid	Relative transformation frequency	% of transformants with plasmid marker of:		% of colonies with plasmid marker ofb:
			Incoming only	Both	Incoming only	Resident only	Both
pIE1115	pMMB600	83	100	0	NTc	NT	NT
pMMB600	pIE1115	<0.001	NT	NT	NT	NT	NT
pIE1115	pIE1108	14	8	92	61	34	5
pIE1108	pIE1115	3	11	89	48	40	12
pIE1120	pMMB600	24	1	99	38	34	28
pMMB600	pIE1120	17	0	100	47	30	23
pIE1120	pIE1108	111	0	100	0	0	100
pIE1108	pIE1120	120	0	100	0	0	100
pIE1130	pMMB600	129	98	2	100	0	0
pMMB600	pIE1130	2	0	100	0	100	0
pIE1130	pIE1108	<0.001	NT	NT	NT	NT	NT
pIE1108	pIE1130	19	100	0	NT	NT	NT

^aThe ability of the incoming plasmid to establish in a bacterial strain containing another resident plasmid was measured in reciprocal transformation experiments by comparing the efficiency of transformation with that of a plasmid-free recipient (set at 100). About 200 fresh transformant colonies were tested for the markers of both plasmids by subculture onto agar plates containing the respective antibiotics separately or combined in one plate. In case of growth on agar selective for both plasmids, such extransformant clones were tested for segregation of plasmid markers during nonselective growth. Per transformation experiment two macrocolonies grown from independent extransformants were inoculated separately into nonselective broth and grown for about 30 generations with three successive subcultures. Appropriate dilutions were then plated onto nonselective agar. About 200 colonies from each culture were tested again for the respective plasmid markers. 

^bSegregation during nonselective growth. 

^cNT, not tested.