Biomaterial Database

Replication of thermosensitive Rts1 plasmid deoxyribonucleic acid at the nonpermissive temperature. 1977

T Yamamoto, and A Kaji

Replication of the thermosensitive drug resistance factor Rts1 was studied at the nonpermissive temperature (42 degrees C). It was concluded from the following observations that replication of this plasmid takes place at 42 degrees C without involving the covalently closed circular (CCC) form of deoxyribonucleic acid (DNA). (i) DNA-DNA- reassociation kinetics studies with purified Rts1 DNA showed that Rts1 DNA increased several-fold during cell growth at 42 degrees C while very little, if any, CCC DNA was synthesized. (ii) When Escherichia coli 20S0(Rts1) was labeled with [3H]thymidine at 42 degrees C, a significant amount of radioactive DNA hybridizable to Rts1 DNA was formed. This DNA was found in a fraction where DNA other than CCC DNA was expected in alkaline sucrose density gradient centrifugation analysis. When E. coli 20S0(Rts1) was labeled at 32 degrees C, the labeled CCC DNA did not disappear during a chase period at 42 degrees C. This indicates that preformed CCC DNA does not participate in replication at the nonpermissive temperature. These results are consistent with the hypothesis that there are two modes of replication of Rts1 DNA, one involving a CCC molecule and the other not involving this form, and that only the latter mode takes place at the nonpermissive temperature.

UI	MeSH Term	Description	Entries
D007612	Kanamycin	Antibiotic complex produced by Streptomyces kanamyceticus from Japanese soil. Comprises 3 components: kanamycin A, the major component, and kanamycins B and C, the minor components.	Kanamycin A,Kanamycin Sulfate,Kantrex
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
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
D004261	DNA Replication	The process by which a DNA molecule is duplicated.	Autonomous Replication,Replication, Autonomous,Autonomous Replications,DNA Replications,Replication, DNA,Replications, Autonomous,Replications, DNA
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004270	DNA, Circular	Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)	Circular DNA,Circular DNAs,DNAs, Circular
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
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures