CONJUGATIVE TRANSFER OF RAFFINOSE METABOLISM IN LACTOCOCCUS-LACTIS

Lactococcus lactis subsp. lactis strains isolated from various sproute d seed products were able to transfer the ability to ferment raffinose in conjugation experiments at frequencies between 10(-4) and 10(-7) p er donor cell. There was no evidence of plasmid transfer, but pulsed-f ield gel electrophoresis analysis showed that all transconjugants had acquired large chromosomal insertions indicative of conjugative transp osons. Raffinose transconjugants contained inserts of 45 or 60 kb at o ne of two chromosomal sites, and these inserts contained two copies of an element related to the lactococcal insertion sequence ISS1. (C) 19 98 Federation of European Microbiological Societies. Published by Else vier Science B.V. All rights reserved.