RECOGNITION OF LEUCONOSTOC-OENOS STRAINS BY THE USE OF DNA RESTRICTION PROFILES

The chromosome of 41 Leuconostoc oenos strains obtained from collectio ns in different countries was analysed with the aim of differentiating the strains. Pulsed field electrophoresis (TAFE) was used to separate large DNA fragments created by the restriction enzymes NotI, SfiI and ApaI, which specifically recognize guanines or cytosines. The genomic DNA of 11 strains was analysed initially with NotI and only four diff erent restriction profiles were observed. The genome size ranged from 1.8 to 2.1 megabase pairs (Mbp). Constant field electrophoresis applie d to DNA treatment with 19 different restriction enzymes showed that t he size of the fragments obtained increased proportionally to the perc entage G + C present at the site of restriction. EcoRI and HindIII pro files revealed that the zone between 9 and 23 kbp allowed differentiat ion of the strains tested. Thus, the 41 strains fell into 30 restricti on groups using only two enzymes. Hybridization with a non-radioactive DNA probe coding for 16S rRNA revealed that there were two 16S genes on the chromosome.