Densovirus
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| Densovirus | ||||||||
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The virus genus Densovirus belongs to the Densovirinae subfamily which belongs to the Parvoviridae family. The viruses of this genus are single-stranded DNA viruses (and are thus, group II viruses under the Baltimore classification). The viruses of this genus are invertebrate viruses. These viruses are only known to infect insects. Examples of species classified into this genus include Galleria mellonella densovirus and Junonia coenia densovirus.
[edit] Structure
These virions consist of non-enveloped capsids that have a round appearance and display icosahedral symmetry.[1] The virions each have an isometric (and therefore spherical) nucleocapsid with a diameter of either 18-22 nm or 20-26 nm.[1] Sixty capsomers are present in a capsid.[1] The structure of each capsomer is described as “a quadrilateral 'kite-shaped' wedge”; the surface is said to have a rough appearance with small projections.[1] The centre of capsids are sometimes visualised as appearing dark due to stain penetration in preparations where only a single species is retrieved. The virions do not appear to contain lipids. The buoyant density (in CsCl) of the virions is 1.4-1.44 g cm-3.[1]
[edit] Genome
These viruses have non-segmented genomes that contains a single linear molecule of single-stranded DNA. The genome codes for structural proteins and is 5000 nucleotides in length and could either be negative-sense or positive-sense. Conserved nucleotide sequences of usually 120-300 or more nucleotides are present at the 3'-terminus and an inverted repeat of this could also be found at the 5'-terminus.[1]
