Mimivirus is a genus of giant viruses, in the family Mimiviridae. Amoeba serve as their natural hosts. This genus contains a single identified species named Acanthamoeba polyphaga mimivirus (APMV). It also refers to a group of phylogenetically related large viruses.
Pseudoviridae is a family of viruses, which includes three genera.
Viral eukaryogenesis is the hypothesis that the cell nucleus of eukaryotic life forms evolved from a large DNA virus in a form of endosymbiosis within a methanogenic archaeon or a bacterium. The virus later evolved into the eukaryotic nucleus by acquiring genes from the host genome and eventually usurping its role. The hypothesis was first proposed by Philip Bell in 2001 and was further popularized with the discovery of large, complex DNA viruses that are capable of protein biosynthesis.
Coccolithovirus is a genus of giant double-stranded DNA virus, in the family Phycodnaviridae. Algae, specifically Emiliania huxleyi, a species of coccolithophore, serve as natural hosts. There is only one described species in this genus: Emiliania huxleyi virus 86.
Phycodnaviridae is a family of large (100–560 kb) double-stranded DNA viruses that infect marine or freshwater eukaryotic algae. Viruses within this family have a similar morphology, with an icosahedral capsid. As of 2014, there were 33 species in this family, divided among 6 genera. This family belongs to a super-group of large viruses known as nucleocytoplasmic large DNA viruses. Evidence was published in 2014 suggesting that specific strains of Phycodnaviridae might infect humans rather than just algal species, as was previously believed. Most genera under this family enter the host cell by cell receptor endocytosis and replicate in the nucleus. Phycodnaviridae play important ecological roles by regulating the growth and productivity of their algal hosts. Algal species such Heterosigma akashiwo and the genus Chrysochromulina can form dense blooms which can be damaging to fisheries, resulting in losses in the aquaculture industry. Heterosigma akashiwo virus (HaV) has been suggested for use as a microbial agent to prevent the recurrence of toxic red tides produced by this algal species. Phycodnaviridae cause death and lysis of freshwater and marine algal species, liberating organic carbon, nitrogen and phosphorus into the water, providing nutrients for the microbial loop.
Mimivirus-dependent virus Sputnik is a subviral agent that reproduces in amoeba cells that are already infected by a certain helper virus; Sputnik uses the helper virus's machinery for reproduction and inhibits replication of the helper virus. It is known as a virophage, in analogy to the term bacteriophage.
Mimiviridae is a family of viruses. Amoeba and other protists serve as natural hosts. The family is divided in up to 4 subfamilies. Viruses in this family belong to the nucleocytoplasmic large DNA virus clade (NCLDV), also referred to as giant viruses.
Chrysochromulina is a genus of haptophytes. This phytoplankton is distributed globally in brackish and marine waters across approximately 60 known species. All Chrysochromulina species are phototrophic, however some have been shown to be mixotrophic, including exhibiting phagotrophy under certain environmental conditions. The cells are small, characterized by having scales, and typically observed using electron microscopy. Some species, under certain environmental conditions have been shown to produce toxic compounds that are harmful to larger marine life including fish.
Mamavirus is a large and complex virus in the Group I family Mimiviridae. The virus is exceptionally large, and larger than many bacteria. Mamavirus and other mimiviridae belong to nucleocytoplasmic large DNA virus (NCLDVs) family. Mamavirus can be compared to the similar complex virus mimivirus; mamavirus was so named because it is similar to but larger than mimivirus.
Cafeteria roenbergensis virus (CroV) is a giant virus that infects the marine bicosoecid flagellate Cafeteria roenbergensis, a member of the microzooplankton community.
A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum Nucleocytoviricota.
Megavirus is a viral genus containing a single identified species named Megavirus chilense, phylogenetically related to Acanthamoeba polyphaga Mimivirus (APMV). In colloquial speech, Megavirus chilensis is more commonly referred to as just “Megavirus”. Until the discovery of pandoraviruses in 2013, it had the largest capsid diameter of all known viruses, as well as the largest and most complex genome among all known viruses.
Pandoravirus is a genus of giant virus, first discovered in 2013. It is the third largest in physical size of any known viral genus, behind Pithovirus and Megaklothovirus. Pandoraviruses have double stranded DNA genomes, with the largest genome size of any known viral genus.
Prymnesiovirus is a genus of viruses, in the family Phycodnaviridae. Alga serve as natural hosts. There is only one species in this genus: Chrysochromulina brevifilum virus PW1 (CbV-PW1). It infects Haptolina brevifila, basionym: Chrysochromulina brevifilum.
Mimivirus-dependent virus Zamilon, or Zamilon, is a virophage, a group of small DNA viruses that infect protists and require a helper virus to replicate; they are a type of satellite virus. Discovered in 2013 in Tunisia, infecting Acanthamoeba polyphaga amoebae, Zamilon most closely resembles Sputnik, the first virophage to be discovered. The name is Arabic for "the neighbour". Its spherical particle is 50–60 nm in diameter, and contains a circular double-stranded DNA genome of around 17 kb, which is predicted to encode 20 polypeptides. A related strain, Zamilon 2, has been identified in North America.
Jingmenvirus is a group of positive-sense single-stranded RNA viruses with segmented genomes. They are primarily associated with arthropods and are one of only two known segmented RNA viruses that infect animal hosts. The first group member, the Jingmen tick virus (JMTV), was described in 2014. Another member, the Guaico Culex virus (GCXV), has a highly unusual multicomponent architecture in which the genome segments are separately enclosed in different viral capsids.
Tupanvirus is a genus of viruses first described in 2018. The genus is composed of two species of virus that are in the giant virus group. Researchers discovered the first isolate in 2012 from deep water sediment samples taken at 3000m depth off the coast of Brazil. The second isolate was collected from a soda lake in Southern Nhecolândia, Brazil in 2014. They are named after Tupã (Tupan), a Guaraní thunder god, and the places they were found. These are the first viruses reported to possess genes for amino-acyl tRNA synthetases for all 20 standard amino acids.
Ortervirales is an order that contains all accepted species of single-stranded RNA viruses that replicate through a DNA intermediate and all accepted species of double-stranded DNA viruses that replicate through an RNA intermediate . The name is derived from the reverse of retro.
Nucleocytoviricota is a phylum of viruses. Members of the phylum are also known as the nucleocytoplasmic large DNA viruses (NCLDV), which serves as the basis of the name of the phylum with the suffix -viricota for virus phylum. These viruses are referred to as nucleocytoplasmic because they are often able to replicate in both the host's cell nucleus and cytoplasm.
Algal viruses are the viruses infecting algae, which are photosynthetic single-celled eukaryotes. As of 2020, there were 61 viruses known to infect algae. Algae are integral components of aquatic food webs and drive nutrient cycling, so the viruses infecting algal populations also impacts the organisms and nutrient cycling systems that depend on them. Thus, these viruses can have significant, worldwide economic and ecological effects. Their genomes varied between 4.4 to 560 kilobase pairs (kbp) long and used double-stranded Deoxyribonucleic Acid (dsDNA), double-stranded Ribonucleic Acid (dsRNA), single-stranded Deoxyribonucleic Acid (ssDNA), and single-stranded Ribonucleic Acid (ssRNA). The viruses ranged between 20 and 210 nm in diameter. Since the discovery of the first algae-infecting virus in 1979, several different techniques have been used to find new viruses infecting algae and it seems that there are many algae-infecting viruses left to be discovered
