Cystovirus
Encyclopedia
Cystovirus is a genus of dsRNA virus
, which infect certain Gram negative bacteria
.
and lipid
outer layer. No other bacteriophage
have any lipid in their outer coat, though the Tectiviridae
and the Corticoviridae
have lipids within their capsid
s.
Most identified cystoviruses infect Pseudomonas
species, but this is likely biased due to the method of screening and enrichment. The type species is Pseudomonas phage Φ6, but there are many other members of this family. Φ7, Φ8, Φ9, Φ10, Φ11, Φ12 and Φ13 have been identified and named, but other cystoviruses have also been isolated.
Members of the Cystoviridae appear to be most closely related to the Reoviridae
, but also share homology
with the Totiviridae
. Cystoviruses are the only bacteriophage
that are more closely related to viruses of eukaryotes than to other phage.
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
, which infect certain Gram negative bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
.
Characteristics
All cystoviruses are distinguished by their three strands (analogous to chromosomes) of dsRNA, totalling ~14 kb in length and their proteinProtein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
and lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
outer layer. No other bacteriophage
Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. They do this by injecting genetic material, which they carry enclosed in an outer protein capsid...
have any lipid in their outer coat, though the Tectiviridae
DNA virus
A DNA virus is a virus that has DNA as its genetic material and replicates using a DNA-dependent DNA polymerase. The nucleic acid is usually double-stranded DNA but may also be single-stranded DNA . DNA viruses belong to either Group I or Group II of the Baltimore classification system for viruses...
and the Corticoviridae
DNA virus
A DNA virus is a virus that has DNA as its genetic material and replicates using a DNA-dependent DNA polymerase. The nucleic acid is usually double-stranded DNA but may also be single-stranded DNA . DNA viruses belong to either Group I or Group II of the Baltimore classification system for viruses...
have lipids within their capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
s.
Most identified cystoviruses infect Pseudomonas
Pseudomonas
Pseudomonas is a genus of gammaproteobacteria, belonging to the family Pseudomonadaceae containing 191 validly described species.Recently, 16S rRNA sequence analysis has redefined the taxonomy of many bacterial species. As a result, the genus Pseudomonas includes strains formerly classified in the...
species, but this is likely biased due to the method of screening and enrichment. The type species is Pseudomonas phage Φ6, but there are many other members of this family. Φ7, Φ8, Φ9, Φ10, Φ11, Φ12 and Φ13 have been identified and named, but other cystoviruses have also been isolated.
Members of the Cystoviridae appear to be most closely related to the Reoviridae
Reoviridae
Reoviridae is a family of viruses that can affect the gastrointestinal system and respiratory tract. Viruses in the family Reoviridae have genomes consisting of segmented, double-stranded RNA...
, but also share homology
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...
with the Totiviridae
Totiviridae
The Totiviridae are a family of viruses. They are non enveloped, icosahedral viruses. The viron is composed of a single capsid protein and are ~40 nanometers in diameter. The capsid has a T=2 symmetry....
. Cystoviruses are the only bacteriophage
Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. They do this by injecting genetic material, which they carry enclosed in an outer protein capsid...
that are more closely related to viruses of eukaryotes than to other phage.