Open AccessConjugational cotransfer of IncFI and IncI conjugative plasmids forming aggregate in a pathogenic Citrobacter freundii strain
Author(s) -
Morzejko Elżbieta,
Panek Elżbieta,
Cebrat Stanisław
Publication year - 1990
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1990.tb04113.x
Subject(s) - plasmid , citrobacter freundii , biology , citrobacter , mutant , strain (injury) , microbiology and biotechnology , enterobacteriaceae , genetics , escherichia coli , gene , anatomy
Two plasmids, pEM4 (IncFI) determining virulence and pEM6 (IncI) determining colicine I production and resistance to tetracycline, have been found in a pathogenic strain of Citrobacter freundii . Even though pEM4 and pEM6 plasmids are conjugative and trasnfer themselves very efficiently during conjugation, a high contrasfer of both plasmid is observed — an unusually high fraction of transconjugants acquiring pEM6 acquires pEM4 and vice versa. The observed contransfer of these plasmids is connected with their ability to complement their conjugational functions. An insertion mutant of pEM4 with decreased frequency of conjugational transfer has been isolated. This mutant (pEM4) lost its ability ot mobilize nonconjugative plasmids. Its transfer is stimulated by pEM6 and it is transferred from (pEM44, pEM6) donors almost exclusively with pEM6 plasmid. The role of contrasfer and stimulation phenomena in spereading of plasmid aggregates in bacterial population is discussed.