title: Behaviour of bacteriophage Mu in Acinetobacter calcoaceticus EBF65/65.
abstract: Transfer of RP4::Mu plasmids from Escherichia coli K12 to Acinetobacter calcoaceticus EBF65/65 was very inefficient compared with RP4 and was only detectable to strains of EBF65/65 lacking pAV2, a cryptic plasmid thought to code for a restriction/modification system. RP4::Mu-derived plasmids transferred from pAV2-strains of EBF65/65 back to E. coli K12 were found to carry defective prophages which had lost the ability to produce detectable phage particles. Re-transfer of these defective plasmids from hsm kappa + and hsm kappa strains of E. coli K12 back to EBF65/65, when compared with the transfer of RP4, provided evidence for a second restriction/modification system in EBF65/65 which affected mainly Mu DNa. Using a mutant Mu prophage, Mu cts62 r23, it was possible to obtain RP4::Mu plasmids in EBF65/65 which were non-defective. These produced viable Mu particles when transferred back to E. coli K12 and could also be thermoinduced in EBF65/65; however, expression of Mu in EBF65/65 was very poor and plaques were only detected on a restrictionless strain of E. coli K12. 'Plasmid suicide by Mu' may enable the development of a method for directed chromosome mobilization in A. calcoaceticus.
mesh_terms: D000150:Acinetobacter / Q000235:genetics*; D003090:Coliphages / Q000235:genetics*; D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics; D010957:Plasmids