What are plasmids and how can they be used?
Structure of Plasmids
- Plasmids are extrachromosomal but are not required for life. ...
- Plasmids have their own replication origin (ORI) and multiply alongside the cell so that each daughter cell has a copy of the plasmid as well.
- Plasmids are not part of the genome, and the same plasmid can exist in multiple species and be transmitted from one to the other.
What is the main function of plasmids?
Plasmids have many different functions. They may contain genes that enhance the survival of an organism, either by killing other organisms or by defending the host cell by producing toxins. Some plasmids facilitate the process of replication in bacteria. In this regard, what are plasmids in bacterial cells?
What is a plasmid and what is its function?
What is Plasmid?
- Table of Content
- Plasmid Structure. Plasmids are extrachromosomal and not essential.
- Plasmid Vector. Plasmids and bacteriophages are frequently used as cloning vectors in DNA recombinant technology. ...
- pBR322 Plasmid. Different antibiotic resistance genes act as a restriction site and to ligate foreign DNA and for the selection of transformants.
- Ti Plasmid. ...
What does a plasmid do?
Plasmids are useful in cloning short segments of DNA. Also, plasmids can be used to replicate proteins, such as the protein that codes for insulin, in large amounts. Additionally, plasmids are being investigated as a way to transfer genes into human cells as part of gene therapy.
What is a plasmid?
At their most basic level, plasmids are small circular pieces of DNA that replicate independently from the host's chromosomal DNA. They are mainly found in bacteria, but also exist naturally in archaea and eukaryotes such as yeast and plants.
How is a plasmid constructed in the lab?
Due to their artificial nature, lab plasmids are commonly referred to as “vectors” or “constructs.” To insert a gene of interest into a vector, scientists may utilize one of a variety of cloning methods (restriction enzyme, ligation independent, Gateway, Gibson, etc).
How do scientists use plasmids?
Generally, scientists use plasmids to manipulate gene expression in target cells. Characteristics such as flexibility, versatility, safety, and cost-effectiveness enable molecular biologists to broadly utilize plasmids across a wide range of applications.
Plasmids
A plasmid is an independent, circular, self-replicating DNA molecule that carries only a few genes. The number of plasmids in a cell generally remains constant from generation to generation.
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Plasmid Definition
A plasmid is a small, circular piece of DNA that is different than the chromosomal DNA, which is all the genetic material found in an organism ’s chromosomes. It replicates independently of chromosomal DNA. Plasmids are mainly found in bacteria, but they can also be found in archaea and multicellular organisms.
Functions of Plasmids
Plasmids have many different functions. They may contain genes that enhance the survival of an organism, either by killing other organisms or by defending the host cell by producing toxins. Some plasmids facilitate the process of replication in bacteria.
General Types of Plasmids
There are many ways to classify plasmids from general to specific. One way is by grouping them as either conjugative or non-conjugative. Bacteria reproduce by sexual conjugation, which is the transfer of genetic material from one bacterial cell to another, either through direct contact or a bridge between the two cells.
Specific Types of Plasmids
There are five main types of plasmids: fertility F-plasmids, resistance plasmids, virulence plasmids, degradative plasmids, and Col plasmids.
Applications of Plasmids
Humans have developed many uses for plasmids and have created software to record the DNA sequences of plasmids for use in many different techniques. Plasmids are used in genetic engineering to amplify, or produce many copies of, certain genes. In molecular cloning, a plasmid is a type of vector.
Related Biology Terms
Bacteria – Single-celled microbes that were one of the first types of lifeforms to evolve on Earth; they can exist independently or inside other organisms.
History
The term plasmid was introduced in 1952 by the American molecular biologist Joshua Lederberg to refer to "any extrachromosomal hereditary determinant." The term's early usage included any bacterial genetic material that exists extrachromosomally for at least part of its replication cycle, but because that description includes bacterial viruses, the notion of plasmid was refined over time to comprise genetic elements that reproduce autonomously.
Properties and characteristics
There are two types of plasmid integration into a host bacteria: Non-integrating plasmids replicate as with the top instance, whereas episomes, the lower example, can integrate into the host chromosome.
Classifications and types
Plasmids may be classified in a number of ways. Plasmids can be broadly classified into conjugative plasmids and non-conjugative plasmids. Conjugative plasmids contain a set of transfer genes which promote sexual conjugation between different cells.
Vectors
Artificially constructed plasmids may be used as vectors in genetic engineering. These plasmids serve as important tools in genetics and biotechnology labs, where they are commonly used to clone and amplify (make many copies of) or express particular genes. A wide variety of plasmids are commercially available for such uses.
Episomes
"Episome" redirects here. For the album by Bill Laswell, Otomo Yoshihide and Tatsuya Yoshida, see Episome (album).
Plasmid maintenance
Some plasmids or microbial hosts include an addiction system or postsegregational killing system (PSK), such as the hok/sok (host killing/suppressor of killing) system of plasmid R1 in Escherichia coli. This variant produces both a long-lived poison and a short-lived antidote.
Yeast plasmids
Yeasts naturally harbour various plasmids. Notable among them are 2 μm plasmids—small circular plasmids often used for genetic engineering of yeast—and linear pGKL plasmids from Kluyveromyces lactis, that are responsible for killer phenotypes.
Molecular Biology and Genetic Engineering
A. Wesley Burks MD, in Middleton's Allergy: Principles and Practice, 2020
Plasmids
David P. Clark, ... Michelle R. McGehee, in Molecular Biology (Third Edition), 2019
Molecular Mechanisms of Antibiotic Resistance in Bacteria
John E. Bennett MD, in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 2020
Plasmids
Incompatibility among plasmids is usually manifested as the inability of a plasmid to be established in a cell that already contains another plasmid or as destabilization of a resident plasmid by a second, incoming plasmid. Experimentally, it has been possible to classify plasmids according to incompatibility groups.
Neisseria gonorrhoeae (Gonorrhea)
John E. Bennett MD, in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 2020
Plasmids
M.E. Tolmasky, in Brenner's Encyclopedia of Genetics (Second Edition), 2013
Plasmid Replication
Two plasmids that cannot be stably maintained in the absence of selection for both are said to be incompatible and to belong to the same incompatibility group. Incompatibility is often used to determine relatedness among plasmids, particularly in replication functions.
Molecular Biology and Genetic Engineering
A. Wesley Burks MD, in Middleton's Allergy: Principles and Practice, 2020
Plasmids
David P. Clark, ... Michelle R. McGehee, in Molecular Biology (Third Edition), 2019
Molecular Mechanisms of Antibiotic Resistance in Bacteria
John E. Bennett MD, in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 2020
Neisseria gonorrhoeae (Gonorrhea)
John E. Bennett MD, in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 2020
Plasmids
M.E. Tolmasky, in Brenner's Encyclopedia of Genetics (Second Edition), 2013
Plasmid Replication
D.K. Chattoraj, in Brenner's Encyclopedia of Genetics (Second Edition), 2013
Rhizobia
Plasmids are bacterial DNA molecules that are smaller than the chromosome (s). Generally, they are dispensable for bacterial growth at least under some conditions. Instead, they typically encode properties that allow growth or otherwise give the bacteria selective advantages under niche-specific conditions.
Plasmid Structure
Plasmids are extrachromosomal and not essential. They are useful but not necessarily present in every organism of the species
Plasmid Vector
Plasmids and bacteriophages are frequently used as a cloning vector in the DNA recombinant technology.
Ti Plasmid
The Tumour inducing or Ti plasmid is present in the bacterium Agrobacterium tumifaciens.
Plasmid Definition
Functions of Plasmids
- Plasmids have many different functions. They may contain genes that enhance the survival of an organism, either by killing other organisms or by defending the host cell by producing toxins. Some plasmids facilitate the process of replication in bacteria. Since plasmids are so small, they usually only contain a few genes with a specific function (as opposed to a large amount of nonc…
General Types of Plasmids
- Conjugative and Non-Conjugative
There are many ways to classify plasmids from general to specific. One way is by grouping them as either conjugative or non-conjugative. Bacteria reproduce by sexual conjugation, which is the transfer of genetic material from one bacterial cell to another, either through direct contact or a … - Incompatibility
Another plasmid classification is by incompatibility group. In a bacterium, different plasmids can only co-occur if they are compatible with each other. An incompatible plasmid will be expelled from the bacterial cell. Plasmids are incompatible if they have the same reproduction strategy i…
Specific Types of Plasmids
- There are five main types of plasmids: fertility F-plasmids, resistance plasmids, virulence plasmids, degradative plasmids, and Col plasmids.
Applications of Plasmids
- Humans have developed many uses for plasmids and have created software to record the DNA sequences of plasmids for use in many different techniques. Plasmids are used in genetic engineering to amplify, or produce many copies of, certain genes. In molecular cloning, a plasmid is a type of vector. A vector is a DNA sequence that can transport foreign genetic material from …
Related Biology Terms
- Bacteria– Single-celled microbes that were one of the first types of lifeforms to evolve on Earth; they can exist independently or inside other organisms.
- Episome– In bacteria, a plasmid that can be inserted into the chromosome. In eukaryotes, plasmid refers to non-chromosomal DNA that can be replicated in the nucleus, such as a virus.
- Conjugative– A category of plasmids that start the process of sexual conjugation in bacteria.
- Bacteria– Single-celled microbes that were one of the first types of lifeforms to evolve on Earth; they can exist independently or inside other organisms.
- Episome– In bacteria, a plasmid that can be inserted into the chromosome. In eukaryotes, plasmid refers to non-chromosomal DNA that can be replicated in the nucleus, such as a virus.
- Conjugative– A category of plasmids that start the process of sexual conjugation in bacteria.
- Bacteriocin– a protein produced by a plasmid in a bacterium that kills other bacteria of a closely related strain.
Quiz
- 1. Which is NOT one of the five main types of plasmids? A. Fertility F-plasmids B. DNA Plasmids C. Col Plasmids D.Virulence Plasmids 2. What is a non-conjugative plasmid? A. A plasmid that cannot be replicated B. A plasmid that cannot trigger the sexual conjugation process C. A plasmid that codes for toxins that kill conjugative plasmids D.A plasmid that prevents the sexual conjuga…
Overview
A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms. In nature, plasmids often carry genes that benefit the su…
History
The term plasmid was introduced in 1952 by the American molecular biologist Joshua Lederberg to refer to "any extrachromosomal hereditary determinant." The term's early usage included any bacterial genetic material that exists extrachromosomally for at least part of its replication cycle, but because that description includes bacterial viruses, the notion of plasmid was refined over time to comprise genetic elements that reproduce autonomously. Later in 1968, it was decided t…
Properties and characteristics
In order for plasmids to replicate independently within a cell, they must possess a stretch of DNA that can act as an origin of replication. The self-replicating unit, in this case, the plasmid, is called a replicon. 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, a…
Classifications and types
Plasmids may be classified in a number of ways. Plasmids can be broadly classified into conjugative plasmids and non-conjugative plasmids. Conjugative plasmids contain a set of transfer genes which promote sexual conjugation between different cells. In the complex process of conjugation, plasmids may be transferred from one bacterium to another via sex pili encoded by some of the t…
Vectors
Artificially constructed plasmids may be used as vectors in genetic engineering. These plasmids serve as important tools in genetics and biotechnology labs, where they are commonly used to clone and amplify (make many copies of) or express particular genes. A wide variety of plasmids are commercially available for such uses. The gene to be replicated is normally inserted into a plasmid th…
Episomes
The term episome was introduced by François Jacob and Élie Wollman in 1958 to refer to extra-chromosomal genetic material that may replicate autonomously or become integrated into the chromosome. Since the term was introduced, however, its use has changed, as plasmid has become the preferred term for autonomously replicating extrachromosomal DNA. At a 1968 symposium in London some participants suggested that the term episome be abandoned, altho…
Plasmid maintenance
Some plasmids or microbial hosts include an addiction system or postsegregational killing system (PSK), such as the hok/sok (host killing/suppressor of killing) system of plasmid R1 in Escherichia coli. This variant produces both a long-lived poison and a short-lived antidote. Several types of plasmid addiction systems (toxin/ antitoxin, metabolism-based, ORT systems) were described in the literature and used in biotechnical (fermentation) or biomedical (vaccine therapy) application…
Yeast plasmids
Yeasts naturally harbour various plasmids. Notable among them are 2 μm plasmids—small circular plasmids often used for genetic engineering of yeast—and linear pGKL plasmids from Kluyveromyces lactis, that are responsible for killer phenotypes.
Other types of plasmids are often related to yeast cloning vectors that include:
• Yeast integrative plasmid (YIp), yeast vectors that rely on integration into the host chromosom…