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Totiviridae
''Totiviridae'' is a family of double-stranded RNA viruses. Giardia lamblia, leishmania, trichomonas vaginalis, and fungi serve as natural hosts. The name of the group derives from Latin ''toti'' which means undivided or whole. There are 28 species in this family, assigned to 5 genera. Structure Viruses in the family ''Totiviridae'' are non-enveloped, double-stranded RNA viruses with icosahedral geometries, and T=2 symmetry. The virion consists of a single capsid protein and is about 40 nanometers in diameter. Genome The genome is composed of a monopartite, linear double-stranded RNA molecule of 4.6–6.7 kilobases. It contains two overlapping open reading frames (ORF) – ''gag'' and ''pol –'' which respectively encode the capsid protein and the RNA-dependent RNA polymerase. Some totiviruses contain a third small potential ORF. Life cycle Viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Totiviridae Genome
''Totiviridae'' is a family of double-stranded RNA viruses. Giardia lamblia, leishmania, trichomonas vaginalis, and fungi serve as natural hosts. The name of the group derives from Latin ''toti'' which means undivided or whole. There are 28 species in this family, assigned to 5 genera. Structure Viruses in the family ''Totiviridae'' are non-enveloped, double-stranded RNA viruses with icosahedral geometries, and T=2 symmetry. The virion consists of a single capsid protein and is about 40 nanometers in diameter. Genome The genome is composed of a monopartite, linear double-stranded RNA molecule of 4.6–6.7 kilobases. It contains two overlapping open reading frames (ORF) – ''gag'' and ''pol –'' which respectively encode the capsid protein and the RNA-dependent RNA polymerase. Some totiviruses contain a third small potential ORF. Life cycle Viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Totiviridae
''Totiviridae'' is a family of double-stranded RNA viruses. Giardia lamblia, leishmania, trichomonas vaginalis, and fungi serve as natural hosts. The name of the group derives from Latin ''toti'' which means undivided or whole. There are 28 species in this family, assigned to 5 genera. Structure Viruses in the family ''Totiviridae'' are non-enveloped, double-stranded RNA viruses with icosahedral geometries, and T=2 symmetry. The virion consists of a single capsid protein and is about 40 nanometers in diameter. Genome The genome is composed of a monopartite, linear double-stranded RNA molecule of 4.6–6.7 kilobases. It contains two overlapping open reading frames (ORF) – ''gag'' and ''pol –'' which respectively encode the capsid protein and the RNA-dependent RNA polymerase. Some totiviruses contain a third small potential ORF. Life cycle Viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-A Helper Virus
''Saccharomyces cerevisiae virus L-A'', also called L-A helper virus, is a member of the ''Totiviridae'' family of viruses found primarily in ''Saccharomyces cerevisiae''. Its discovery in the 1970s was the main starting point of research on yeast virology. It is a ~4.6 kb double-stranded RNA virus with no extracellular phase and so is inherited through vertical cytoplasmic transmission. Additionally, in many strains of the yeast, it is found along with another virus called the M virus (or "M dsRNA", "Saccharomyces cerevisiae killer virus"), known to encode the killer toxin in many ''S. cerevisiae'' strains which confers the ability to kill neighboring sensitive cells that do not harbor the virus. It is indeed for this reason the virus is referred to as a helper virus, due to the M genome's dependence on it for its own survival and replication. (More recently, the M dsRNA is described as a satellite RNA.) A Yeast lineage with a M/killer virus is known as a " killer strain". Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Totivirus
''Totivirus'' is a genus of double-stranded RNA viruses in the family ''Totiviridae''. Fungi serve as natural hosts. The name of the group derives from Latin ''toti'' which means undivided or whole. There are seven species in this genus. Structure Viruses in the genus ''Totivirus'' are non-enveloped, with icosahedral symmetry, and T=2 architecture. The diameter is around 40 nm. Genome Totiviruses have a genome of 4700–6700 nucleotides in length and only a single copy of the genome is present in the particle. The nucleic acid content of a totivirus capsid is usually of one segment but can also contain three or four segments of linear double stranded RNA. The genome contains two large overlapping open reading frames (ORFs). These open reading frames (ORFs) code for a capsid protein (CP) and an RNA-dependent RNA polymerase (RdRp). The 5' end of the positive strand of the dsRNA genome has no cap and is very structured. Totiviruses contain a long 5' untranslated region (5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giardiavirus
''Giardiavirus'' is a genus of viruses, in the family Totiviridae ''Totiviridae'' is a family of double-stranded RNA viruses. Giardia lamblia, leishmania, trichomonas vaginalis, and fungi serve as natural hosts. The name of the group derives from Latin ''toti'' which means undivided or whole. There are 28 spec .... Protozoa serve as natural hosts. There is only one species in this genus: ''Giardia lamblia virus''. Structure Viruses in ''Giardiavirus'' are non-enveloped, with icosahedral geometries, and T=2 symmetry. The diameter is around 36 nm. Genomes are linear, around 6277kb in length. The genome has 2 open reading frames. Life cycle Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment to host receptors, which mediates endocytosis. Replication follows the double-stranded RNA virus replication model. Double-stranded rna virus transcription is the method of transcription. Translation takes place by -1 ribosomal frameshifting, and vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichomonasvirus
''Trichomonasvirus'' is a genus of viruses, in the family ''Totiviridae''. The protozoan parasite ''Trichomonas vaginalis ''Trichomonas vaginalis'' is an anaerobic, flagellated protozoan parasite and the causative agent of a sexually transmitted disease called trichomoniasis. It is the most common pathogenic protozoan that infects humans in industrialized countri ...'' serves as the natural host. There are four species in this genus. Taxonomy The following four species are assigned to the genus: * '' Trichomonas vaginalis virus 1'' * '' Trichomonas vaginalis virus 2'' * '' Trichomonas vaginalis virus 3'' * '' Trichomonas vaginalis virus 4'' Structure Viruses in ''Trichomonasvirus'' are non-enveloped, with icosahedral geometries, and T=2 symmetry. The diameter is around 36 nm. Genomes are linear and non-segmented, around 4.6-4.9kb in length. The genome has 2 open reading frames. Life cycle Viral replication is cytoplasmic. Entry into the host cell is achieved by att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leishmaniavirus
''Leishmaniavirus'' (also known as ''Leishmania'' RNA virus or LRV) is a genus of double-stranded RNA virus, in the family ''Totiviridae''. Protozoa serve as natural hosts, and Leishmaniaviruses are present in several species of the human protozoan parasite '' Leishmania''. There are two species in this genus. History The presence of virus-like particles in ''Leishmania hertigi'' was first reported in 1974. Various molecular descriptions of ''Leishmaniavirus'' were revealed over the subsequent decade, and mostly performed on members of the South American ''L. (Viannia)'' subgenus of parasites (which carries the LRV1 species) such as ''L. guyanensis'' (''L.g'') and then later in '' L. braziliensis'' (''L.b''). Recently, interest in these microbial viruses has been renewed by a finding that they may play a role in leishmanial pathology. Prevalence The prevalence of LRV1 in human parasites is still largely unknown. So far, no LRV1 has been detected in other key ''L. (Viannia)'' s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victorivirus
''Victorivirus'' is a genus of viruses, in the family ''Totiviridae ''Totiviridae'' is a family of double-stranded RNA viruses. Giardia lamblia, leishmania, trichomonas vaginalis, and fungi serve as natural hosts. The name of the group derives from Latin ''toti'' which means undivided or whole. There are 28 spec ...''. Filamentous fungi serve as natural hosts. There are 14 species in this genus. Structure Viruses in ''Victorivirus'' are non-enveloped, with icosahedral geometries, and T=2 symmetry. The diameter is around 40 nm. Genomes are linear, around 4.6-6.7kb in length. The genome has 2 open reading frames. Life cycle Viral replication is cytoplasmic. Entry into the host cell is achieved by virus remains intracellular. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. Translation takes place by RNA termination-reinitiation. The virus exits the host cell by cell to cell movem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA-dependent RNA Polymerase
RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to typical DNA-dependent RNA polymerases, which all organisms use to catalyze the transcription of RNA from a DNA template. RdRp is an essential protein encoded in the genomes of most RNA-containing viruses with no DNA stage including SARS-CoV-2. Some eukaryotes also contain RdRps, which are involved in RNA interference and differ structurally from viral RdRps. History Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template. Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double-stranded RNA Viruses
Double-stranded RNA viruses (dsRNA viruses) are a polyphyletic group of viruses that have double-stranded genomes made of ribonucleic acid. The double-stranded genome is used to transcribe a positive-strand RNA by the viral RNA-dependent RNA polymerase (RdRp). The positive-strand RNA may be used as messenger RNA (mRNA) which can be translated into viral proteins by the host cell's ribosomes. The positive-strand RNA can also be replicated by the RdRp to create a new double-stranded viral genome. Double-stranded RNA viruses are classified in two separate phyla ''Duplornaviricota'' and ''Pisuviricota'' (specifically class ''Duplopiviricetes''), which are in the kingdom ''Orthornavirae'' and realm ''Riboviria''. The two groups do not share a common dsRNA virus ancestor. Double-stranded RNA viruses evolved two separate times from positive-strand RNA viruses. In the Baltimore classification system, dsRNA viruses belong to Group III. Virus group members vary widely in host range (anim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars (including its own descendants, the Romance languages) supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition. Latin is a highly inflected language, with three distinct genders (masculine, feminine, and neuter), six or seven noun cases (nominative, accusative, genitive, dative, ablative, and vocative), five declensions, four verb conjuga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) 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 proteins making up the capsid are called capsid proteins or viral coat proteins (VCP). The capsid and inner genome is called the nucleocapsid. Capsids are broadly classified according to their structure. The majority of the viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while the helical shape resembles the shape of a spring, taking the space of a cylinder but not being a cylinder itself. The capsid faces may consist of one or more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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