Loss of plasmids containing cloned inserts coding for novobiocin resistance or novobiocin sensitivity in Haemophilus influenzae

Journal Article · Fri Jun 01 04:00:00 EDT 1984 · J. Bacteriol.; (United States)

OSTI ID:5946873

Setlow, J K; Spikes, D; Ledbetter, M

Plasmids pNov1 and pNov1s, coding for resistance and sensitivity to novobiocin, respectively, were readily lost from wild-type Haemophilus influenzae but retained in a strain lacking an inducible defective prophage. The plasmid loss could be partly or wholly eliminated by a low-copy-number mutation in the plasmid or by the presence of certain antibiotic resistance markers in the host chromosome. Release of both phage HP1c1, measured by plaque assay, and defective phage, measured by electron microscopy, was increased when the plasmids were present. The frequency of recombination between pNov1 and the chromosome, causing the plasmid to be converted to pNov1s, could under some circumstances be decreased from the normal 60 to 70% to below 10% by the presence of a kanamycin resistance marker in the chromosome. This suggested that a gene product coded for by the plasmid, the expression of which was affected by the kanamycin resistance marker, was responsible for the high recombination frequency. Evidence was obtained from in vitro experiments that the gene product was a gyrase.

• Research Organization: Brookhaven National Lab., Upton, NY
• OSTI ID: 5946873
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 158:3; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

550700* -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BACTERIA
BACTERIOPHAGES
BIOLOGICAL MARKERS
CELL CONSTITUENTS
CHROMOSOMES
CLONING
DNA
DRUGS
ELECTRON MICROSCOPY
ENZYMES
GENETIC ENGINEERING
HAEMOPHILUS
MICROORGANISMS
MICROSCOPY
MUTATIONS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PARASITES
PLASMIDS
RECOMBINANT DNA
SENSITIVITY
VIRUSES