Restriction enzyme fingerprinting of trimethoprim resistance plasmids

Plasmids with Blunt - End Restriction Enzyme 1

TA cloning is one of the simplest and most efficient methods for the cloning of PCR products. The procedure exploits the terminal transferase activity of certain thermophilic DNA polymerases, including Thermus aquaticus (Taq) polymerase. Taq polymerase has non-template dependent activity which preferentially adds a single adenosine to the 3'-ends of a double stranded DNA molecule, and thus most...

Unusual expression of new low-level-trimethoprim-resistance plasmids.

In a survey, 42% of trimethoprim-resistant clinical members of the family Enterobacteriaceae were able to transfer trimethoprim resistance to standard Escherichia coli strains when selection was made on complex bacteriological media. When transfer experiments were performed with minimal medium, another 16% of the clinical strains were shown to have transferred trimethoprim resistance. Twelve tr...

Mapping of trimethoprim resistance genes from epidemiologically related plasmids.

Trimethoprim resistance dihydrofolate reductase genes from plasmids known to be exchanging between human and animal populations were mapped. The dihydrofolate reductase gene has been highly conserved in all plasmids, but differences in the flanking regions provide evidence that the most recent exchange of plasmids between the two ecosystems has been from animals to humans.

Restriction enzyme analysis of plasmids from Haemophilus influenzae.

Examination of Haemophilus influenzae strains isolated in New Orleans revealed ampicillin-resistant strains with plasmids of size classes not previously detected in North America. The molecular weight of plasmids in five ampicillin-resistant strains ranged from 0.8 x 10(6) daltons (0.8 Mdal) to 36 Mdal. The molecular weights of the plasmids were determined by sucrose gradient centrifugation, el...

One-tube restriction enzyme digest and fluorescent labeling for restriction endonuclease fingerprinting single-strand conformational polymorphism.