TRANSFER OF HYBRID PLASMIDS BASED ON THE REPLICON PRR17 FROM ESCHERICHIA-COLI TO BACTEROIDES AND PREVOTELLA STRAINS

New shuttle vectors based on a Prevotella ruminicola 9.5 kb cryptic pl asmid (pRRI7) inserted within the Escherichia coli vector pKC71, carry ing the Cc(r)/Em(r) Bacteroides marker, were constructed. These constr ucts (pKBR23-1 and pKBR23-2) were transferred into Bacteroides distaso nis, Bacteroides thetaiotaomicron, Bacteroides uniforms and into P. ru minicola NCFB 2202 either by conjugal mobilization or by electroporati on. Another pRRI7 derivative based on pKC72, PKBR23-3, was smaller (13 .1 kb) and non-mobilizable. By electroporation, it was transferred to Bact. distasonis and P. ruminicola. Being derived from pRRI7 which is compatible with the shuttle plasmid pRRI207, the host/vector combinati on involving P. ruminicola NCFB 2202 and pKBR23-3 offers new possibili ties for genetic investigations in rumen anaerobic bacteria after furt her introduction of a second readily selectable marker within pRRI207 or pKBR23-3.