TABLE 4.

Conjugation efficiencies under various conjugation conditions^a

E. coli growth medium	Conjugation temp (°C)	Light/dark	Conjugation time (h)	Conjugation efficiency (tcg/CFU of donor)
LB	37	Light	16	5.8 × 10–5
mPYE	37	Light	16	1.2 × 10–5
LB	42	Light	16	1.2 × 10–4
LB	37	Dark	16	2.1 × 10–5
LB	37	Light	3	9 × 10–6

^aLB, Luria-Bertani broth (Miller’s formula); mPYE, modified PYE medium; light, conjugations were performed under 790-nm LED lights (∼30 μmol photons m⁻² s⁻¹); dark, conjugation plates were wrapped in foil; tcg/CFU of donor, number of erythromycin-resistant transformant heliobacterial colonies normalized to the number of E. coli donor cells (measured as CFU).