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Table 3 Conjugation efficiency determined with the vector pBBR1MCS.

From: Genetic tools for the investigation of Roseobacter clade bacteria

Strains

Conjugants/viable cells

Conjugants/ml

P. inhibens

1.0 × 10-6

1.0 × 105

P. gallaeciensis

2.0 × 10-4

3.0 × 103

O. indolifex

2.7 × 10-2

5.0 × 105

R. litoralis

5.0 × 10-4

1.0 × 103

R. denitrificans

2.0 × 10-4

2.0 × 103

D. shibae

2.4 × 10-2

2.0 × 106

  1. aThe recipient Roseobacter strains were cultivated for 18 h in MB at 30°C and the donor E. coli ST18 was grown up to the logarithmic phase (OD578 = 0.5-0.6) in LB supplemented with 50 μg/ml ALA at 37°C. Mating mixtures were incubated on hMB supplemented with 50 μg/ml ALA over 24 h at 30°C in a donor:recipient ratio 10:1. Afterwards, the cells were resuspended in 1 ml MB, diluted serially in 1.7% (w/v) sea salt solution and plated on hMB with and without antibiotics, respectively, to determine the number of conjugants and viable cells. A donor:recipient ratio of 5:1 revealed the same results. The results represent the mean of three independent experiments performed in duplicate.