Plasmid

plasmidsepisomeplasmid vectorvectorepisomesepisomalgenetic materialmegaplasmidplasmid DNAplasmid vectors
A plasmid is a small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.wikipedia
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Genomic DNA

genomicgDNAchromosomal DNA
A plasmid is a small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.
Genomic deoxyribonucleic acid is chromosomal DNA, in contrast to extra-chromosomal DNAs like plasmids.

Vector (molecular biology)

vectorvectorsVector DNA
Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms.
In molecular cloning, a vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed (e.g., plasmid, cosmid, Lambda phages).

Transformation (genetics)

transformationtransformedgenetic transformation
In the laboratory, plasmids may be introduced into a cell via transformation.
Transformation is one of three processes for horizontal gene transfer, in which exogenous genetic material passes from one bacterium to another, the other two being conjugation (transfer of genetic material between two bacterial cells in direct contact) and transduction (injection of foreign DNA by a bacteriophage virus into the host bacterium).

Virus

virusesviralvirion
However, plasmids, like viruses, are not generally classified as life.
The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria.

Horizontal gene transfer

lateral gene transferhorizontal transfergene transfer
This host-to-host transfer of genetic material is one mechanism of horizontal gene transfer, and plasmids are considered part of the mobilome.
It often involves temperate bacteriophages and plasmids.

Recombinant DNA

recombinantrecombinant proteingene splicing
Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms.
Vectors are generally derived from plasmids or viruses, and represent relatively small segments of DNA that contain necessary genetic signals for replication, as well as additional elements for convenience in inserting foreign DNA, identifying cells that contain recombinant DNA, and, where appropriate, expressing the foreign DNA.

Bacterial conjugation

conjugationconjugativeExconjugant
Plasmids are transmitted from one bacterium to another (even of another species) mostly through conjugation.
coli conjugation the donor'' cell provides a conjugative or mobilizable genetic element that is most often a plasmid or transposon.

Mobilome

This host-to-host transfer of genetic material is one mechanism of horizontal gene transfer, and plasmids are considered part of the mobilome.
The compositions of mobilomes differ among lineages of life, with transposable elements being the major mobile elements in eukaryotes, and plasmids and prophages being the major types in prokaryotes.

Molecular cloning

cloneclonedrecombinant DNA technology
Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms.
coli (Escherichia coli'') and a plasmid cloning vector.

DNA

deoxyribonucleic aciddouble-stranded DNAdsDNA
A plasmid is a small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.
A few DNA sequences in prokaryotes and eukaryotes, and more in plasmids and viruses, blur the distinction between sense and antisense strands by having overlapping genes.

Iteron

A typical bacterial replicon may consist of a number of elements, such as the gene for plasmid-specific replication initiation protein (Rep), repeating units called iterons, DnaA boxes, and an adjacent AT-rich region.
Iterons are directly repeated DNA sequences which play an important role in regulation of plasmid copy number in bacterial cells.

Plasmid copy number

The normal number of copies of plasmid that may be found in a single cell is called the Plasmid copy number, and is determined by how the replication initiation is regulated and the size of the molecule.
Plasmids must regulate their copy number (average number of plasmid copies per cell) to ensure that they do not excessively burden the host or become lost during cell division.

Virulence factor

virulence factorsfactorsimmunoevasive
Some of these genes encode traits for antibiotic resistance or resistance to heavy metal, while others may produce virulence factors that enable a bacterium to colonize a host and overcome its defences, or have specific metabolic functions that allow the bacterium to utilize a particular nutrient, including the ability to degrade recalcitrant or toxic organic compounds.

Cell (biology)

cellcellscellular
The size of the plasmid varies from 1 to over 200 kbp, and the number of identical plasmids in a single cell can range anywhere from one to thousands under some circumstances.

Plasmid partition system

partition systempartitioning systems
These systems, which include the parABS system and parMRC system, are often referred to as the partition system or partition function of a plasmid.
A plasmid partition system is a mechanism that ensures the stable inheritance of plasmids during bacterial cell division.

Bacteria

bacteriumbacterialEubacteria
They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms.
Bacteria can also contain plasmids, small extra-chromosomal DNAs that may contain genes for various useful functions such as antibiotic resistance, metabolic capabilities, or various virulence factors.

Pilus

pilitype IV piliType I Pili
However, some classes of plasmids encode the conjugative "sex" pilus necessary for their own transfer.
Typically, the DNA transferred consists of the genes required to make and transfer pili (often encoded on a plasmid), and so is a kind of selfish DNA; however, other pieces of DNA are often co-transferred and this can result in dissemination of genetic traits throughout a bacterial population, such as antibiotic resistance.

ParABS system

parA
These systems, which include the parABS system and parMRC system, are often referred to as the partition system or partition function of a plasmid.
Originally identified as a genetic element required for faithful partitioning of low-copy-number plasmids, the parABS system is a broadly conserved molecular mechanism for plasmid partitioning and chromosome segregation in bacteria.

Fertility factor (bacteria)

F-plasmidF factorF plasmid
The F factor is carried on the F episome, the first episome to be discovered.

Molecular biology

molecular biologistmolecularmolecular microbiology
The term plasmid was introduced in 1952 by the American molecular biologist Joshua Lederberg to refer to "any extrachromosomal hereditary determinant."
In this technique, DNA coding for a protein of interest is cloned using polymerase chain reaction (PCR), and/or restriction enzymes into a plasmid (expression vector).

Archaea

archaeonarcheaarchaebacteria
They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms.
Smaller independent pieces of DNA, called plasmids, are also found in archaea.

Ligation (molecular biology)

ligationligatedligate
These cloning vectors contain a site that allows DNA fragments to be inserted, for example a multiple cloning site or polylinker which has several commonly used restriction sites to which DNA fragments may be ligated.
It is an essential laboratory procedure in the molecular cloning of DNA whereby DNA fragments are joined together to create recombinant DNA molecules, such as when a foreign DNA fragment is inserted into a plasmid.

Pathogen

pathogenspathogenicpathogenicity
A bacterium may participate in opportunistic infections in immunocompromised hosts, acquire virulence factors by plasmid infection, become transferred to a different site within the host, or respond to changes in the overall numbers of other bacteria present.

Multiple cloning site

polylinkerMCSmulticloning site
These cloning vectors contain a site that allows DNA fragments to be inserted, for example a multiple cloning site or polylinker which has several commonly used restriction sites to which DNA fragments may be ligated. These include a gene that confers resistance to particular antibiotics (ampicillin is most frequently used for bacterial strains), an origin of replication to allow the bacterial cells to replicate the plasmid DNA, and a suitable site for cloning (referred to as a multiple cloning site).
A multiple cloning site (MCS), also called a polylinker, is a short segment of DNA which contains many (up to ~20) restriction sites - a standard feature of engineered plasmids.

Cosmid

cosmids
To clone longer lengths of DNA, lambda phage with lysogeny genes deleted, cosmids, bacterial artificial chromosomes, or yeast artificial chromosomes are used.
A cosmid is a type of hybrid plasmid that contains a Lambda phage cos sequence