Biomaterial Database

Copy numbers of coexisting plasmids in Escherichia coli K-12. 1978

P T Barth, and H Richards, and N Datta

A strain of Escherichia coli K-12 carrying eight compatible and distinguishable plasmids was constructed. The amounts of plasmid DNA (measured as supercoiled molecules) per chromosome in this strain was about equal to the sum of the plasmid DNAs, extracted under controlled conditions, from strains each carrying one of the eight plasmids. Analysis of these DNA preparations showed that each plasmid in the multiplasmid strain was present in the same proportion per chromosome as in the single-plasmid strains. Also the level of phenotypic expression of each plasmid in the multiplasmid strain was the same as in the single-plasmid strains. Each plasmid, therefore, appears to control its own copy number irrespective of the presence of other compatible plasmids.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D011815	R Factors	A class of plasmids that transfer antibiotic resistance from one bacterium to another by conjugation.	R Factor,R Plasmid,R Plasmids,Resistance Factor,Resistance Factors,Factor, R,Factor, Resistance,Factors, R,Factors, Resistance,Plasmid, R,Plasmids, R
D003227	Conjugation, Genetic	A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.	Bacterial Conjugation,Conjugation, Bacterial,Genetic Conjugation
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004278	DNA, Superhelical	Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.	DNA, Supercoiled,DNA, Supertwisted,Supercoiled DNA,Superhelical DNA,Supertwisted DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli