Intergeneric conjugation procedure Streptomyces rimosus R7 and M4018 spores (104) were suspended in 500 ll of 2 · YT medium and treated at a range of temperatures from room temperature (nonheated spores) to 55C for 10 min. The donor strain, E. coli ET12567 (pUZ8002 ⁄ pIJ8600), was grown in LB until anOD600 of 0Æ4–0Æ6. The cells were washed twice with LB and resuspended in a final volume of 500 ll of LB (108 cells). Equal volumes of E. coli cells and the S. rimosus
spore suspension were mixed and spread on MS, ISP 4 and TSA (Oxoid) containing 10 m mol l)1 MgCl2, and incubated at 30C for 16–20 h. The plates were flooded with 1 ml water containing nalidixic acid (500 lg ml)1)
and thiostrepton (1000 lg ml)1and incubated furtherfor 5–7 days. For conjugation with mycelia, S. rimosus was grown in 50 ml TSB (in which it grows in a very