A bacteriophage, also known informally as a phage, is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν, meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm.
Enterobacteria phage λ is a bacterial virus, or bacteriophage, that infects the bacterial species Escherichia coli. It was discovered by Esther Lederberg in 1950. The wild type of this virus has a temperate life cycle that allows it to either reside within the genome of its host through lysogeny or enter into a lytic phase, during which it kills and lyses the cell to produce offspring. Lambda strains, mutated at specific sites, are unable to lysogenize cells; instead, they grow and enter the lytic cycle after superinfecting an already lysogenized cell.
Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, cellular biology, molecular biology, biochemistry, and biotechnology. Researchers search for mutations in a gene or induce mutations in a gene to link a gene sequence to a specific phenotype. Molecular genetics is a powerful methodology for linking mutations to genetic conditions that may aid the search for treatments/cures for various genetics diseases.
Escherichia virus T4 is a species of bacteriophages that infect Escherichia coli bacteria. It is a double-stranded DNA virus in the subfamily Tevenvirinae from the family Myoviridae. T4 is capable of undergoing only a lytic lifecycle and not the lysogenic lifecycle. The species was formerly named T-even bacteriophage, a name which also encompasses, among other strains, Enterobacteria phage T2, Enterobacteria phage T4 and Enterobacteria phage T6.
Filamentous bacteriophage is a family of viruses (Inoviridae) that infect bacteria. The phages are named for their filamentous shape, a worm-like chain, about 6 nm in diameter and about 1000-2000 nm long. The coat of the virion comprises five types of viral protein, which are located during phage assembly in the inner membrane of the host bacteria, and are added to the nascent virion as it extrudes through the membrane. The simplicity of this family makes it an attractive model system to study fundamental aspects of molecular biology, and it has also proven useful as a tool in immunology and nanotechnology.
The phi X 174 bacteriophage is a single-stranded DNA (ssDNA) virus that infects Escherichia coli, and the first DNA-based genome to be sequenced. This work was completed by Fred Sanger and his team in 1977. In 1962, Walter Fiers and Robert Sinsheimer had already demonstrated the physical, covalently closed circularity of ΦX174 DNA. Nobel prize winner Arthur Kornberg used ΦX174 as a model to first prove that DNA synthesized in a test tube by purified enzymes could produce all the features of a natural virus, ushering in the age of synthetic biology. In 1972–1974, Jerard Hurwitz, Sue Wickner, and Reed Wickner with collaborators identified the genes required to produce the enzymes to catalyze conversion of the single stranded form of the virus to the double stranded replicative form. In 2003, it was reported by Craig Venter's group that the genome of ΦX174 was the first to be completely assembled in vitro from synthesized oligonucleotides. The ΦX174 virus particle has also been successfully assembled in vitro. In 2012, it was shown how its highly overlapping genome can be fully decompressed and still remain functional.
Bacteriophage T7 is a bacteriophage, a virus that infects bacteria. It infects most strains of Escherichia coli and relies on these hosts to propagate. Bacteriophage T7 has a lytic life cycle, meaning that it destroys the cell it infects. It also possesses several properties that make it an ideal phage for experimentation: its purification and concentration have produced consistent values in chemical analyses; it can be rendered noninfectious by exposure to UV light; and it can be used in phage display to clone RNA binding proteins.
A mycobacteriophage is a member of a group of bacteriophages known to have mycobacteria as host bacterial species. While originally isolated from the bacterial species Mycobacterium smegmatis and Mycobacterium tuberculosis, the causative agent of tuberculosis, more than 4,200 mycobacteriophage have since been isolated from various environmental and clinical sources. 2,042 have been completely sequenced. Mycobacteriophages have served as examples of viral lysogeny and of the divergent morphology and genetic arrangement characteristic of many phage types.
Salmonella virus P22 is a bacteriophage in the Podoviridae family that infects Salmonella typhimurium. Like many phages, it has been used in molecular biology to induce mutations in cultured bacteria and to introduce foreign genetic material. P22 has been used in generalized transduction and is an important tool for investigating Salmonella genetics.
Bacteriophage MS2, commonly called MS2, is an icosahedral, positive-sense single-stranded RNA virus that infects the bacterium Escherichia coli and other members of the Enterobacteriaceae. MS2 is a member of a family of closely related bacterial viruses that includes bacteriophage f2, bacteriophage Qβ, R17, and GA.
P1 is a temperate bacteriophage that infects Escherichia coli and some other bacteria. When undergoing a lysogenic cycle the phage genome exists as a plasmid in the bacterium unlike other phages that integrate into the host DNA. P1 has an icosahedral head containing the DNA attached to a contractile tail with six tail fibers. The P1 phage has gained research interest because it can be used to transfer DNA from one bacterial cell to another in a process known as transduction. As it replicates during its lytic cycle it captures fragments of the host chromosome. If the resulting viral particles are used to infect a different host the captured DNA fragments can be integrated into the new host's genome. This method of in vivo genetic engineering was widely used for many years and is still used today, though to a lesser extent. P1 can also be used to create the P1-derived artificial chromosome cloning vector which can carry relatively large fragments of DNA. P1 encodes a site-specific recombinase, Cre, that is widely used to carry out cell-specific or time-specific DNA recombination by flanking the target DNA with loxP sites.
A P1-derived artificial chromosome, or PAC, is a DNA construct derived from the DNA of P1 bacteriophages and Bacterial artificial chromosome. It can carry large amounts of other sequences for a variety of bioengineering purposes in bacteria. It is one type of the efficient cloning vector used to clone DNA fragments in Escherichia coli cells.
Corticovirus is a genus of viruses in the family Corticoviridae. Corticoviruses are bacteriophages; that is, their natural hosts are bacteria. The genus contains two species. The name is derived from Latin cortex, corticis. However, prophages closely related to PM2 are abundant in the genomes of aquatic bacteria, suggesting that the ecological importance of corticoviruses might be underestimated. Bacteriophage PM2 was first described in 1968 after isolation from seawater sampled from the coast of Chile.
Escherichia virus T5, sometimes called Bacteriophage T5 is a caudal virus within the family Demerecviridae. This bacteriophage specifically infects E. coli bacterial cells and follows a lytic life cycle.
Bacteriophage P2, scientific name Escherichia virus P2, is a temperate phage that infects E. coli. It is a tailed virus with a contractile sheath and is thus classified in the genus Peduovirus, subfamily Peduovirinae, family Myoviridae within order Caudovirales. This genus of viruses includes many P2-like phages as well as the satellite phage P4.
Enquatrovirus is a genus of bacteriophages in the order Caudovirales, in the family Podoviridae. Bacteria serve as natural hosts. There is currently only one species in this genus: the type species Escherichia virus N4.
Ff phages is a group of almost identical filamentous phage including phages f1, fd, M13 and ZJ/2, which infect bacteria bearing the F fertility factor. The virion is a flexible filament measuring about 6 by 900 nm, comprising a cylindrical protein tube protecting a single-stranded circular DNA molecule at its core. The phage codes for only 11 gene products, and is one of the simplest viruses known. It has been widely used to study fundamental aspects of molecular biology. George Smith and Greg Winter used f1 and fd for their work on phage display for which they were awarded a share of the 2018 Nobel Prize in Chemistry. Early experiments on Ff phages used M13 to identify gene functions, and M13 was also developed as a cloning vehicle, so the name M13 is sometimes used as an informal synonym for the whole group of Ff phages.
Clyde A. Hutchison III is an American biochemist and microbiologist notable for his research on site-directed mutagenesis and synthetic biology. He is Professor Emeritus of Microbiology and Immunology at the University of North Carolina at Chapel Hill, Distinguished Professor at the J Craig Venter Institute, a member of the National Academy of Sciences, and a fellow of the American Academy of Arts and Sciences.
Spiroplasma phage 1-R8A2B is a filamentous bacteriophage in the genus Vespertiliovirus of the family Plectroviridae, part of the group of single-stranded DNA viruses. The virus has many synonyms, such as SpV1-R8A2 B, Spiroplasma phage 1, and Spiroplasma virus 1, SpV1. SpV1-R8A2 B infects Spiroplasma citri. Its host itself is a prokaryotic pathogen for citrus plants, causing Citrus stubborn disease.
Escherichia virus CC31, formerly known as Enterobacter virus CC31, is a dsDNA bacteriophage of the subfamily Tevenvirinae responsible for infecting the bacteria family of Enterobacteriaceae. It is one of two discovered viruses of the genus Karamvirus, diverging away from the previously discovered T4virus, as a clonal complex (CC). CC31 was first isolated from Escherichia coli B strain S/6/4 and is primarily associated with Escherichia, even though is named after Enterobacter.
