TABLE 5.
Intergeneric gordonii-cAM373-induced plasmid transfer
| Donora | Donor inductionb | Recipient | Filter mating time | Selection | Frequencyc | Cotransfer of unselected marker (%)d |
|---|---|---|---|---|---|---|
| JH2-2/pAM378/pAMS470 | No | OG1X | 4 h | Em | 7.8 × 100 | 30 |
| Tc | 4.4 × 100 | 86 | ||||
| JH2-2/pAMS470 | No | OG1X | 4 h | Em | < 3.0 × 10−8 | NA |
| JH2-2/pAM378/pAMS470 | No | CH1S | 30 min | Em | 3.8 × 10−7 | ND |
| Tc | 1.1 × 10−5 | ND | ||||
| JH2-2/pAM378/pAMS470 | Yes | CH1S | 30 min | Em | 7.0 × 10−4 | 0 |
| Tc | 1.1 × 10−4 | 7 | ||||
| JH2-2/pAM378/pAMS749-12 | No | CH1S | 30 min | Em | < 3.6 × 10−8 | NA |
| Tc | 4.8 × 10−6 | 0 | ||||
| JH2-2/pAM378/pAMS749-12 | Yes | CH1S | 30 min | Em | < 4.3 × 10−8 | NA |
| Tc | 7.3 × 10−6 | 0 | ||||
| JH2-2/pAMS470 | No | CH1S | 4 h | Em | < 6.5 × 10−8 | NA |
| JH2-2/pAM378 | No | CH1S | 4 h | Tc | 1.2 × 10−5 | NA |
pAM378 is a pAM373::Tn918 Tc-resistant derivative responsive to pheromone. pAMS749-12 is a cloning vector carrying Em resistance. pAMS470 is pAMS749-12 carrying oriT373.
Induction involved 90-min exposure of the donor to 50 ng/ml of the synthetic peptide gordonii-cAM373 before donor and recipient were mixed.
Conjugation frequencies are given as transconjugants per donor. Frequencies of conjugation to recipient CH1S are mean averages of 3 independent experiments. High rates for pheromone-induced conjugative transfer for positive-control E. faecalis recipients are consistent with published results (11).
To determine the cotransfer rate, 200 transconjugants in each case were screened for resistance to the unselected marker (Em or Tc). NA, not applicable; ND, not determined.