Biomaterial Database

Evidence for a disseminated plasmid in Streptococcus mutans. 1978

F L Macrina, and C L Scott

Based on a survey of 86 isolates, approximately 5% of all naturally occurring strains of Streptococcus mutans contains a 3.6 X 10(6)-dalton (3.6-megadalton) multicopy plasmid of unknown function. The amount of plasmid deoxyribonucleic acid per chromosome varies from 2 to 6% depending on the host strain. About 13% of the total covalently closed circular deoxyribonucleic acid in each of the four plasmid-containing strains consists of dimeric molecules, with interlocked circular forms predominating. Site-specific restriction endonucleases have been identified that cleave this 3.6-megadalton plasmid at single and at multiple sites. Each of the four plasmids is cleaved once by the HindIII and BamHI restriction enzymes. The HpaI, TaqI, and HhaI enzymes generate two, five, and six components, respectively, and the digestion products of each of the four plasmids are identical. Because the four plasmid-containing S. mutans strains are physiologically unique with respect to one another, we conclude this plasmid to be a disseminated extrachromosomal element in S. mutans.

UI	MeSH Term	Description	Entries
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
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
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
D004587	Electrophoresis, Agar Gel	Electrophoresis in which agar or agarose gel is used as the diffusion medium.	Electrophoresis, Agarose Gel,Agar Gel Electrophoresis,Agarose Gel Electrophoresis,Gel Electrophoresis, Agar,Gel Electrophoresis, Agarose
D004720	Endonucleases	Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.	Endonuclease
D013295	Streptococcus mutans	A polysaccharide-producing species of STREPTOCOCCUS isolated from human dental plaque.