Behaviour of IncP-1 plasmids and a miniMu transposon in a marine Vibrio sp.: isolation of starvation inducible lac operon fusions

Abstract

To identify operons exclusively induced at the onset of starvation in a marine Vibrio strain ( Vibrio sp. S14) a broad host range vector suitable for delivery of a mini-Mu lac transposon to Gram-negative bacteria was constructed. Using this vector (pJO100) a set of starvation inducible lac fusion mutants was obtained in Vibrio sp. S14. Of these fusions the induction pattern of a carbon starvation inducible fusion is presented. To monitor the induction of starvation promotors a rapid and sensitive β-galactosidase assay for dilute cell suspensions was developed. The behaviour of broad host range IncP-1 type plasmids in Vibrio sp. S14 was investigated. The conjugative transfer frequency of such plasmids was found to be high. The mutagenesis system developed in this study was found to be useful for other marine bacteria.