Physical and genetic analysis of the ColD plasmid

Abstract

The plasmid ColD-CA23, a high-copy-number plasmid of 5.12 kilobases, encodes colicin D, a protein of approximately 87,000 daltons which inhibits bacterial protein synthesis. Colicin D production is under the control of the Escherichia coli SOS regulatory system and is released to the growth medium via the action of the lysis gene product(s). A detailed map of the ColD plasmid was established for 10 restriction enzymes. Using in vitro insertional omega mutagenesis and in vivo insertional Tn5 mutagenesis, we localized the regions of the plasmid responsible for colicin D activity (cda), for mitomycin C-induced lysis (cdl), and for colicin D immunity (cdi). These genes were all located contiguously on a 2,400-base-pair fragment similar to a large number of other Col plasmids (A, E1, E2, E3, E8, N, and CloDF). The ColD plasmid was mobilizable by conjugative transfer by helper plasmids of the IncFII incompatibility group, but not by plasmids belonging to the groups IncI-alpha or IncP. The location of the mobilization functions was determined by deletion analysis. The plasmid needs a segment of 400 base pairs, which is located between the mob genes and the gene for autolysis, for its replication.

Construction of a ColD cda Promoter-Based SOS-Green Fluorescent Protein Whole-Cell Biosensor with Higher Sensitivity toward Genotoxic Compounds than Constructs Based on recA , umuDC , or sulA Promoters

“…While the Ϫ35 to Ϫ10 distance varied by only 2 bases (16)(17)(18), the S/D-to-ATG codon varied by as much as 6 bases (4-10).…”

“…The preferred promoters have typically been the recA, umuDC, and sulA promoters, as was the case with the rec-lac test (32), the umu test, and the SOS chromotest, respectively. A relatively unstudied promoter from the ColD plasmid gene cda (16,17) has also been applied with success in the SOS lux and SOS-LUX-LAC-FLUORO assays (34,38). Although recent studies have performed genome-wide gene expression profiling of E. coli following DNA damage (9,37), no candidates better than the promoters described here have been found.…”

Third-Generation-Cephalosporin-Resistant Klebsiella pneumoniae Isolates from Humans and Companion Animals in Switzerland: Spread of a DHA-Producing Sequence Type 11 Clone in a Veterinary Setting

“…Selected isolates were used to determine, by PCR (PBRT kit; Diatheva), the Inc group of plasmids carrying bla DHA-1 , bla CTX-M-1 , bla CTX-M-3 , bla CTX-M-14 , bla CTX-M-15 , and bla OXA-48 after electroporation into Escherichia coli TOP10 (Invitrogen) and filter mating conjugation using either E. coli JF33 (Rif r ) or E. coli J53 (sodium azide resistant; kindly provided by L. Poirel) as the recipient (16). Transformed cells were selected on MuellerHinton II agar containing either 70 g/ml ampicillin, 2 g/ml cefotaxime, or 0.5 g/ml meropenem.…”

A New Sulfonamide Resistance Gene ( sul3 ) in Escherichia coli Is Widespread in the Pig Population of Switzerland

“…Conjugations using E. coli rl0044 as a donor and E. coli JF33 (a rifampin-resistant E. coli K-12 derivative [2]) as a recipient strain were performed as described previously (1). The transconjugants were selected on Mueller-Hinton agar plates containing 50 g of rifampin and 200 g of sulfamethoxazole per ml.…”