reatment of spores.
We also demonstrated that 24-h mycelia could be used
quite effectively as recipient for intergeneric conjugation
instead of spores. As S. rimosus grows in TSB in a highly
dispersed manner, no mechanical homogenization or sonication
was needed, as suggested for mycelia of poorly
sporulating S. peucetius (Paranthaman and Dharmalingum
2003). The conjugation efficiency achieved with S. rimosus
mycelia (5Æ8 · 10)4
) was better than that obtained with
mycelium of S. peucetius (1Æ5 · 10)4
, Paranthaman and
Dharmalingum 2003) and contrasts markedly with unsuccessful
attempts to achieve conjugation with mycelium of
S. natalensis (Enr´iquez et al. 2006). Because preparing
mycelium is practically simpler, we recommended its use,
rather than spores, in S. rimosus conjugation experiments.
In addition, TSA (Oxoid) agar yielded the highest
efficiency for S. rimosus–E. coli conjugations.