A RAPID MECHANICAL LYSING PROCEDURE FOR ROUTINE ANALYSIS OF PLASMIDS FROM LACTOBACILLI, ISOLATED FROM SOURDOUGHS

Variations in cell wall composition of lactobacilli complicate attempt s to standardize plasmid detection on the basis of enzymatic lysing pr ocedures. Mechanical disruption of cell walls by a horizontal mixer-mi ll proved to be more effective, rapid and reproducible. In order to ju dge the risk of damaging plasmid deoxyribonucleic acids (DNA) in this way, plasmid profiles obtained after enzymatic lysing and mechanical d isruption of cell walls were compared. As no differences were detected the mechanical procedure was accepted as a suitable method for routin e analysis of plasmid profiles.