''Spbetavirus'' (formerly ''Spbetalikevirus'' and sometimes ''SPbeta-like viruses'') is a genus of
virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
es in the order
Caudovirales, in the family
Siphoviridae. Bacteria serve as natural hosts. There is only one species in this genus: ''Bacillus virus SPbeta''.
Structure
Spbetaviruses are
nonenveloped
A viral envelope is the outermost layer of many types of viruses. It protects the genetic material in their life cycle when traveling between host cells. Not all viruses have envelopes.
Numerous human pathogenic viruses in circulation are encase ...
, with a head and tail. The head is about 81 nm in diameter. The tail is long, but fairly rigid, at about 355 nm long, 10 nm wide. It has six club-shaped terminal fibers and no collar.
Genome
Genomes are linear, around 134kb in length.
[ Bacillus phage SPbeta has been fully sequenced. It has about 134k nucleotides, with 185 proteins. The complete genome is availabl]
here
ref name=NCBI>
Life cycle
Viral replication is cytoplasmic. The virus attaches to the host cell's adhesion receptors using its terminal fiber, and degrades the cell wall using viral exolysin enough to eject the viral DNA into the host cytoplasm vi
Replication follows the replicative transposition model. DNA-templated transcription is the method of transcription. Once the viral genes have been replicated, the procapsid is assembled and packed. The tail is then assembled and the mature virions are released via lysis. Bacteria serve as the natural host. Transmission routes are passive diffusion.
History
According to
ICTV's ninth report, the genus ''Spbetalikevirus'' was first accepted under the name ''SPbeta-like viruses'', assigned to family ''
Siphoviridae'', order ''
Caudovirales''. The genus was first renamed to ''Spbetalikevirus'' in 2012,
and later to ''Spbetavirus'' in 2015.
References
External links
Viralzone: SpbetalikevirusICTV
{{Taxonbar, from=Q24805797, from2=Q18965098, from3=Q24808601, from4=Q18813158
Siphoviridae
Virus genera
Bacillus phages