Determination of RLakt insert of plasmid clones 17 and 30. SalI and NotI digestion of clone 17 and 30 plasmids produced two bands corresponding to the 2.6 kb RLakt insert and 3.0 kb pMET7 vector (A). Negative clones 15 and 28 were also included in the analysis. PCR using RLakt-specific primers (refer to text) produced the predicted 896 bp band for clones 17 and 30 (B).