string: These strains were transformed with plasmid pME1983 (Gisi et al., 1999), a derivative of pTrc99A (Amersham) carrying the dcmA gene from Methylophilus sp. strain DM11 (Bader & Leisinger, 1994) under IPTG control, and the control plasmid pME1984 carrying the dcmA gene in antisense orientation to the P
   trc
   promoter.