|
Enterobacteria Phage N15
''Ravinvirus'' (synonym ''N15-like viruses'', ''N15likevirus'') is a genus of viruses in the order ''Caudovirales'', in the family ''Siphoviridae''. Bacteria serve as natural hosts, with transmission achieved through passive diffusion. There is only one species in this genus: ''Escherichia virus N15''. Structure Ravinviruses are nonenveloped, with a head and tail. The head is about 60 nm in diameter. The tail is long and flexible, at about 140 nm long, 8 nm wide, with short brush-like terminal fibers. Genome ''Escherichia virus N15'' has been fully sequenced. It has about 46k nucleotides, with 60 proteins. The complete genome is availablhereref name=NCBI> Life cycle Viral replication is cytoplasmic. The virus attaches to the host cell's adhesion receptors using its terminal fiber, and ejects 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viruses
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 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudovirales
''Caudovirales'' is an order of viruses known as the tailed bacteriophages (''cauda'' is Latin for "tail"). Under the Baltimore classification scheme, the ''Caudovirales'' are group I viruses as they have double stranded DNA (dsDNA) genomes, which can be anywhere from 18,000 base pairs to 500,000 base pairs in length. The virus particles have a distinct shape; each virion has an icosahedral head that contains the viral genome, and is attached to a flexible tail by a connector protein. The order encompasses a wide range of viruses, many containing genes of similar nucleotide sequence and function. However, some tailed bacteriophage genomes can vary quite significantly in nucleotide sequence, even among the same genus. Due to their characteristic structure and possession of potentially homologous genes, it is believed these bacteriophages possess a common origin. There are 14 families, 73 subfamilies, 927 genera, and 2,814 species in the order. This makes ''Caudovirales'' the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphoviridae
''Siphoviridae'' is a family of double-stranded DNA viruses in the order ''Caudovirales''. Bacteria and archaea serve as natural hosts. There are 1,166 species in this family, assigned to 366 genera and 22 subfamilies. The characteristic structural features of this family are a nonenveloped head and noncontractile tail. Structure Viruses in ''Siphoviridae'' are non-enveloped, with icosahedral and head-tail geometries (morphotype B1) or a prolate capsid (morphotype B2), and T=7 symmetry. The diameter is around 60 nm. Members of this family are also characterized by their filamentous, cross-banded, noncontractile tails, usually with short terminal and subterminal fibers. Genomes are double stranded and linear, around 50 kb in length, containing about 70 genes. The guanine/cytosine content is usually around 52%. Life cycle Viral replication is cytoplasmic. Entry into the host cell is achieved by adsorption into the host cell. Replication follows the replicative transposition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Envelope
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 encased in lipid bilayers, and they infect their target cells by causing the viral envelope and cell membrane to fuse. Although there are effective vaccines against some of these viruses, there is no preventative or curative medicine for the majority of them. In most cases, the known vaccines operate by inducing antibodies that prevent the pathogen from entering cells. This happens in the case of enveloped viruses when the antibodies bind to the viral envelope proteins. The membrane fusion event that triggers viral entrance is caused by the viral fusion protein. Many enveloped viruses only have one protein visible on the surface of the particle, which is required for both mediating adhesion to the cell surface and for the subsequent membrane fusi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Committee On Taxonomy Of Viruses
The International Committee on Taxonomy of Viruses (ICTV) authorizes and organizes the taxonomic classification of and the nomenclatures for viruses. The ICTV has developed a universal taxonomic scheme for viruses, and thus has the means to appropriately describe, name, and classify every virus that affects living organisms. The members of the International Committee on Taxonomy of Viruses are considered expert virologists. The ICTV was formed from and is governed by the Virology Division of the International Union of Microbiological Societies. Detailed work, such as delimiting the boundaries of species within a family, typically is performed by study groups of experts in the families. History The International Committee on Nomenclature of Viruses (ICNV) was established in 1966, at the International Congress for Microbiology in Moscow, to standardize the naming of viruses. The ICVN published its first report in 1971. For viruses infecting vertebrates, the first report included ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
