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Encyclopedia > Virus
Viruses
Herpes simplex virus 1 (HSV-1)
Herpes simplex virus 1 (HSV-1)
Virus classification
Group: I–VII
Groups

I: dsDNA viruses
II: ssDNA viruses
III: dsRNA viruses
IV: (+)ssRNA viruses
V: (-)ssRNA viruses
VI: ssRNA-RT viruses
VII: dsDNA-RT viruses Look up virus in Wiktionary, the free dictionary. ... Image File history File links Herpes_simpex_virus. ... Virus classification involves naming and placing viruses into a taxonomic system. ... A DNA virus is a virus that has DNA as its genetic material and does not use an RNA intermediate during replication. ... A DNA virus is a virus that has DNA as its genetic material and does not use an RNA intermediate during replication. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... ss-RNA RT is the single stranded Ribonucleic acid genome that is present in the HIV virus. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ...

A virus (from the Latin noun virus, meaning toxin or poison) is a sub-microscopic particle (ranging in size from 20–300 nm) that can infect the cells of a biological organism. Viruses can replicate themselves only by infecting a host cell. They therefore cannot reproduce on their own. At the most basic level, viruses consist of genetic material contained within a protective protein coat called a capsid. They infect a wide variety of organisms: both eukaryotes (animals, plants, protists, and fungi) and prokaryotes (bacteria and archaea). A virus that infects bacteria is known as a bacteriophage, often shortened to phage. The study of viruses is known as virology and people who study viruses are known as virologists. Viruses cause several serious human diseases, such as AIDS, influenza and rabies. Therapy is difficult for viral diseases as antibiotics have no effect on viruses and few antiviral drugs are known. The best way to prevent viral diseases is with a vaccine, which produces immunity. For other uses, see Latin (disambiguation). ... This article or section does not cite any references or sources. ... The skull and crossbones symbol (Jolly Roger) traditionally used to label a poisonous substance. ... A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... Look up nano in Wiktionary, the free dictionary. ... ‹ The template below (Unit of length) is being considered for deletion. ... In medicine, infectious disease or communicable disease is disease caused by a biological agent (e. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology is the science of life (from the Greek words bios = life and logos = word). ... “Life on Earth” redirects here. ... Genetic material is used to store the genetic information of an organic life form. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A capsid is the outer shell of a virus. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all... Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... Prokaryotes (pro-KAR-ee-oht) (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos, pl. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (), or archaebacteria, are a major group of microorganisms. ... A bacteriophage (from bacteria and Greek phagein, to eat) is a virus that infects bacteria. ... Virology, often considered a part of microbiology or of pathology, is the study of organic viruses: their structure and classification, their ways to infect and exploit cells to reproduce and cause disease, the techniques to isolate and culture them, and their potential uses in research and therapy. ... Acquired Immune Deficiency Syndrome or acquired immunodeficiency syndrome (AIDS or Aids) is a collection of symptoms and infections resulting from the specific damage to the immune system caused by the human immunodeficiency virus (HIV). ... Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by an RNA virus of the family Orthomyxoviridae (the influenza viruses). ... Staphylococcus aureus - Antibiotics test plate. ... Antiviral drugs are a class of medication used specifically for treating viral infections. ... A vaccine is an antigenic preparation used to establish immunity to a disease. ... Immunity is a medical term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. ...


It has been argued extensively whether viruses are living organisms. Most virologists consider them non-living,[1][2][3] as they do not meet all the criteria of the generally accepted definition of life. For example, unlike living organisms as defined, viruses do not respond to changes in the environment. For other uses, see Life (disambiguation). ...

Contents

Discovery

Computer-generated image of virions
Computer-generated image of virions

Viral diseases such as rabies, yellow fever and smallpox have affected humans for many centuries. There is hieroglyphical evidence of polio in the ancient Egyptian empire,[4] however, the cause of these diseases was unknown at the time. In 1717, Mary Montagu, the wife of an English ambassador to the Ottoman Empire, observed local women inoculating their children against smallpox.[5] In the late 18th century, Edward Jenner observed and studied Miss Sarah Nelmes, a milkmaid who had previously caught cowpox and was subsequently found to be immune to smallpox, a similar, but devastating virus. Jenner developed the first vaccine based on these findings; after lengthy (but successful) vaccination campaigns the World Health Organization (WHO) certified the eradication of smallpox in 1979.[6] Image File history File links Download high-resolution version (1280x961, 315 KB) I made this Graphic with Cinema4D. Its free for all ;-) Author: Felix Bittmann, Germany I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU... Image File history File links Download high-resolution version (1280x961, 315 KB) I made this Graphic with Cinema4D. Its free for all ;-) Author: Felix Bittmann, Germany I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU... Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. ... Poliomyelitis (polio), or infantile paralysis, is a viral paralytic disease. ... Mary Wortley Montague, by Charles Jervas, after 1716. ... For other uses, see Ottoman (disambiguation). ... Inoculation, originally Variolation, is a method of purposefully infecting a person with smallpox (Variola) in a controlled manner so as to minimise the severity of the infection and also to induce immunity against further infection. ... Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. ... Portrait of Edward Jenner Edward Jenner, FRS, (17 May 1749 – 26 January 1823) was an English country doctor who studied nature and his natural surroundings from childhood and practiced medicine in Berkeley, Gloucestershire, England. ... Cowpox is a disease of the skin caused by a virus (Cowpox virus) that is related to the Vaccinia virus. ... Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. ... A vaccine is an antigenic preparation used to establish immunity to a disease. ... A vial of the vaccine against influenza. ... The World Health Organization (WHO) is a specialized agency of the United Nations (UN) that acts as a coordinating authority on international public health. ... Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. ...


In the late 19th century Charles Chamberland developed a porcelain filter with pores small enough to filter bacteria, yet retain all viable viruses.[7] Dimitri Ivanovski used this filter to study tobacco mosaic virus. He published experiments showing that crushed leaf extracts of infected tobacco plants were still infectious after filtering through such filters. At about the same time, several others documented filterable disease-causing agents, with several independent experiments showing that viruses were different from bacteria, yet they could also cause disease in living organisms. These experiments showed that viruses are orders of magnitudes smaller than bacteria. The term virus was coined by the Dutch microbiologist Martinus Beijerinck. Charles Chamberland was a French microbiologist who worked with Louis Pasteur. ... Dmitry Iosifovich Ivanovsky (1864-1920) was a Russian-Ukrainian biologist who was the first to discover viruses (1892). ... This article does not cite any references or sources. ... Martinus Willem Beijerinck (March 16, 1851 - January 1, 1931) was a Dutch microbiologist and botanist. ...


In the early 20th century, Frederick Twort discovered that bacteria could be attacked by viruses. Felix d'Herelle, working independently, showed that a preparation of viruses caused areas of cellular death on thin cell cultures spread on agar. Counting the dead areas allowed him to estimate the original number of viruses in the suspension. The invention of Electron microscopy provided the first look at viruses. In 1935 Wendell Stanley crystallised the tobacco mosaic virus and found it to be mostly protein. A short time later the virus was separated into protein and nucleic acid parts. In 1939, Max Delbrück and E.L. Ellis demonstrated that, in contrast to cellular organisms, bacteriophage reproduce in "one step", rather than exponentially. This article belongs in one or more categories. ... Félix dHerelle (April 25, 1873 – February 22, 1949), French-Canadian microbiologist, one of the discoverers of bacteriophages (small viruses that only attack and kill bacteria), and inventor of phage therapy. ... Epithelial cells in culture, stained for keratin (red) and DNA (green) Cell culture is the process by which either prokaryotic or eukaryotic cells are grown under controlled conditions. ... This does not adequately cite its references or sources. ... The electron microscope is a microscope that can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. ... Wendell Meredith Stanley (August 16, 1904 - June 15, 1971) was an American biochemist, virologist and Nobel prize laureate. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Look up nucleic acid in Wiktionary, the free dictionary. ... Max Delbrück (September 4, 1906 - March 9, 1981) was a German biologist. ...


A major problem for early virologists was the inability to propagate viruses on sterile culture media, as is done with cellular microorganisms. This limitation required medical virologists to infect living animals with infectious material, which is dangerous. The first breakthrough came in 1931, when Ernest William Goodpasture demonstrated the growth of influenza and several other viruses in fertile chicken eggs. However, many viruses would not grow in chicken eggs, and a more flexible technique was needed for propagation of viruses. The solution came in 1949 when John Franklin Enders, Thomas H. Weller and Frederick Chapman Robbins together developed a technique to grow polio virus in cultures of living animal cells. Their methods have since been extended and applied to the growth of many viruses and other infectious agents that do not grow on sterile culture media. Dr. Ernest William Goodpasture (October 17, 1886 – September 20, 1960), was an American pathologist and physician. ... Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by an RNA virus of the family Orthomyxoviridae (the influenza viruses). ... John Franklin Enders (February 10, 1887 – 1985) was an American medical scientist. ... Dr. Thomas Huckle Weller (born June 15, 1915) was an American virologist, he, John Franklin Enders and Frederick Chapman Robbins were awarded a Nobel Prize in Physiology or Medicine in 1954 for showing how to cultivate poliomyelitis viruses in the test tube. ... Frederick Chapman Robbins (1916-2003) was a Nobel laureate in Medicine and Physiology in 1956 along with Enders and Weller. ... Poliomyelitis (polio) is a viral paralytic disease. ...


Origins

The origins of modern viruses are not entirely clear. It may be that no single mechanism can account for all viruses. They do not fossilize well, so molecular techniques have been the most useful means of hypothesising how they arose. Research in microfossil identification and molecular biology may yet discern fossil evidence dating to the Archean or Proterozoic eons. Two main hypotheses currently exist.[8] For other uses, see Fossil (disambiguation). ... Molecular biology is the study of biology at a molecular level. ... For other uses of the term, see Fossil (disambiguation) Fossils are the mineralized remains of animals or plants or other artifacts such as footprints. ... The Archean is a geologic eon; it is a somewhat antiquated term for the time span between 2500 million years before the present and 3800 million years before the present. ... The Proterozoic (IPA: ) is a geological eon representing a period before the first abundant complex life on Earth. ... In general usage, an eon (sometimes spelled aeon) is a very long period of time. ...


Small viruses with only a few genes may be runaway stretches of nucleic acid originating from the genome of a living organism. Their genetic material could have been derived from transferable genetic elements such as plasmids or transposons, which are prone to moving within, leaving, and entering genomes. Figure 1: Schematic drawing of a bacterium with plasmids enclosed. ... Transposons are sequences of DNA that can move around to different positions within the genome of a single cell, a process called transposition. ...


Viruses with larger genomes, such as poxviruses, may have once been small cells which parasitised larger host cells. Over time, genes not required by their parasitic lifestyle would have been lost in a streamlining process known as retrograde-evolution or reverse-evolution. The bacteria Rickettsia and Chlamydia are living cells that, like viruses, can only reproduce inside host cells. They lend credence to the streamlining hypothesis, as their parasitic lifestyle is likely to have caused the loss of genes that enabled them to survive outside a host cell. Genera Subfamily Chordopoxvirinae    Orthopoxvirus    Parapoxvirus    Avipoxvirus    Capripoxvirus    Leporipoxvirus    Suipoxvirus    Molluscipoxvirus    Yatapoxvirus Subfamily Entomopoxvirinae    Entomopoxvirus A    Entomopoxvirus B    Entomopoxvirus C Poxviruses (members of the family Poxviridae) can infect as a family both vertebrate and invertebrate animals. ... Species Rickettsia felis Rickettsia prowazekii Rickettsia rickettsii Rickettsia typhi Rickettsia conorii Rickettsia africae etc. ... Chlamydia is a common term for infection with any bacterium belonging to the phylum Chlamydiae. ...


It is hypothetically possible that viruses represent a primitive form of self replicating DNA and are a precursor to life as it is presently defined.


Other infectious particles which are even simpler in structure than viruses include viroids, satellites, and prions. Families Pospiviroidae Avsunviroidae Viroids are plant pathogens that consist of a short stretch (a few hundred nucleobases) of highly complementary, circular, single-stranded RNA without the protein coat that is typical for viruses. ... Groups Satellite viruses Satellite nucleic acids Satellites are subviral agents composed of nucleic acids; they depend for their multiplication on coinfection of a host cell with a helper virus. ... A prion (IPA: [1] ) — short for proteinaceous infectious particle (-on by analogy to virion) — is a type of infectious agent composed only of protein. ...


Classification

For more details on this topic, see Virus classification.
Baltimore classification
Group Contains
I dsDNA viruses
II ssDNA viruses
III dsRNA viruses
IV (+)ssRNA viruses
V (-)ssRNA viruses
VI ssRNA-RT viruses
VII dsDNA-RT viruses
ss: single-stranded, ds: double stranded
RT: reverse transcribing

In taxonomy, the classification of viruses is rather difficult due to the lack of a fossil record and the dispute over whether they are living or non-living. They do not fit easily into any of the domains of biological classification and therefore classification begins at the family rank. However, the domain name of Acytota (without cells) has been suggested. This would place viruses on a par with the other domains of Eubacteria, Archaea, and Eukarya. Not all families are currently classified into orders, nor all genera classified into families. Virus classification involves naming and placing viruses into a taxonomic system. ... A DNA virus is a virus that has DNA as its genetic material and does not use an RNA intermediate during replication. ... A DNA virus is a virus that has DNA as its genetic material and does not use an RNA intermediate during replication. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... ss-RNA RT is the single stranded Ribonucleic acid genome that is present in the HIV virus. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... Look up taxonomy in Wiktionary, the free dictionary. ... In biology, a domain (also superregnum, superkingdom, or empire) is the top-level grouping of organisms in scientific classification, higher than a kingdom. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... A common alternate meaning of virus is computer virus. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are microscopic, unicellular organisms. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (), or archaebacteria, are a major group of microorganisms. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...


As an example of viral classification, the chicken pox virus belongs to family Herpesviridae, subfamily Alphaherpesvirinae and genus Varicellovirus. It remains unranked in terms of order. The general structure is as follows. Chicken pox, also spelled chickenpox, is a common childhood disease caused by the varicella_zoster virus (VZV), also known as human herpes virus 3 (HHV_3), one of the eight herpesviruses known to affect humans. ... Genera Subfamily Alphaherpesvirinae    Simplexvirus    Varicellovirus    Mardivirus    Iltovirus Subfamily Betaherpesvirinae    Cytomegalovirus    Muromegalovirus    Roseolovirus Subfamily Gammaherpesvirinae    Lymphocryptovirus    Rhadinovirus Unassigned    Ictalurivirus The Herpesviridae are a family of DNA viruses that cause diseases in humans and animals. ... {{{subdivision_ranks}}} Subfamily Alphaherpesvirinae Alphaherpesvirinae is a subfamily of Herpesviridae primarily distinguished by reproducing more quickly than other subfamilies of Herpesviridae. ... Varicellovirus var′i-sel′ō-vi′rÅ­s is a subfamily of Alphaherpesvirinae. ...

Order (-virales)
Family (-viridae)
Subfamily (-virinae)
Genus (-virus)
Species (-virus)

The International Committee on Taxonomy of Viruses (ICTV) developed the current classification system and put in place guidelines that put a greater weighting on certain virus properties in order to maintain family uniformity. In determining order, taxonomists should consider the type of nucleic acid present, whether the nucleic acid is single- or double-stranded, and the presence or absence of an envelope. After these three main properties, other characteristics can be considered: the type of host, the capsid shape, immunological properties and the type of disease it causes. In scientific classification used in biology, the order (Latin: ordo, plural ordines) is a rank between class and family (termed a taxon at that rank). ... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... ... For other uses, see Genus (disambiguation). ... The hierarchy of scientific classification. ... The International Committee on Taxonomy of Viruses (ICTV) is a committee which authorizes and organizes the taxonomic classification of viruses. ... There are very few or no other articles that link to this one. ...


In addition to this classification system, the Nobel Prize-winning biologist David Baltimore devised the Baltimore classification system. This places a virus into one of seven Groups, which distinguish viruses based on their mode of replication and genome type. The ICTV classification system is used in conjunction with the Baltimore classification system in modern virus classification. The Nobel Prizes (Swedish: ) are awarded for Physics, Chemistry, Literature, Peace, and Physiology or Medicine. ... David Baltimore (b. ... Virus classification involves naming and placing viruses into a taxonomic system. ...


Structure

A complete virus particle, known as a virion, is little more than a gene transporter, consisting in its simplest form of nucleic acid surrounded by a protective coat of protein called a capsid. A capsid is composed of proteins encoded by the viral genome and its shape serves as the basis for morphological distinction. Virally coded protein subunits - sometimes called protomers - will self-assemble to form the capsid, generally requiring the presence of the virus genome - however, many complex viruses code for proteins which assist in the construction of their capsid.[8] Proteins associated with nucleic acid are known as nucleoproteins, and the association of viral capsid proteins with viral nucleic acid is called a nucleocapsid. For a non-technical introduction to the topic, see Introduction to Genetics. ... Look up nucleic acid in Wiktionary, the free dictionary. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A capsid is the outer shell of a virus. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... The term morphology in biology refers to the outward appearance (shape, structure, colour, pattern) of an organism or taxon and its component parts. ... A nucleoprotein is any protein which is structurally associated with nucleic acid (either DNA or RNA). ...


In general, there are four main morphological virus types:

Image Helical viruses
Diagram of a helical capsid
Diagram of a helical capsid
Helical capsids are composed of a single type of subunit stacked around a central axis to form a helical structure which may have a central cavity, or hollow tube. This arrangement results in rod-shaped or filamentous virions: these can be anything from short and highly rigid, to long and very flexible. The genetic material - generally single-stranded RNA, but also ssDNA in the case of certain phages - is bound into the protein helix, by charge interactions between the negatively-charged nucleic acid and positive charges on the protein. Overall, the length of a helical capsid is related to the length of the nucleic acid contained within it, while the diameter is dependent on the size and arrangement of protomers. The well-studied Tobacco mosaic virus is an example of a helical virus.
Image Icosahedral viruses
Electron micrograph of icosahedral virions
Electron micrograph of icosahedral virions
Icosahedral capsid symmetry results in a spherical appearance of viruses at low magnification but actually consists of capsomers arranged in a regular geometrical pattern, similar to a soccer ball, hence they are not truly "spherical". Capsomers are ring shaped structures constructed from five to six copies of protomers. These associate via non-covalent bonding to enclose the viral nucleic acid, though generally less intimately than helical capsids, and may involve one or more protomers.

Icosahedral architecture was employed by R. Buckminster-Fuller in his geodesic dome, and is the most efficient way of creating an enclosed robust structure from multiple copies of a single protein. The number of proteins required to form a spherical virus capsid is denoted by the T-number,[9] where 60×t proteins are necessary. In the case of the hepatitis B virus the T-number is 4, therefore 240 proteins assemble to form the capsid. Download high resolution version (1268x829, 113 KB)Structure of the coat protein of the Tobacco Mosaic Virus (Acetylseryltyrosylserylisol. ... Download high resolution version (1268x829, 113 KB)Structure of the coat protein of the Tobacco Mosaic Virus (Acetylseryltyrosylserylisol. ... This article does not cite any references or sources. ... Image File history File links Coronaviruses_004_lores. ... Image File history File links Coronaviruses_004_lores. ... A player (wearing the red kit) has penetrated the defence (in the white kit) and is taking a shot at goal. ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... Richard Buckminster “Bucky” Fuller (July 12, 1895 – July 1, 1983)[1] was an American visionary, designer, architect, poet, author, and inventor. ... Spaceship Earth in Epcot Center at Walt Disney World is perhaps one of the most famous examples of a large scale geodesic sphere. ... Hepatitis B is an inflammation of the liver and is caused by the Hepatitis B virus (HBV), a member of the Hepadnavirus family[1] and one of hundreds of unrelated viral species which cause viral hepatitis. ...

Image Enveloped viruses
Diagram of enveloped HIV
In addition to a protein capsid many viruses are able to envelope themselves in a modified form of one of the cell membranes - the outer membrane surrounding an infected host cell, or from internal membranes such as nuclear membrane or endoplasmic reticulum - thus gaining an outer lipid bilayer known as a viral envelope. This membrane is studded with proteins coded for by the viral genome and host genome; however the lipid membrane itself and any carbohydrates present are entirely host-coded. The Influenza virus and HIV use this strategy.

The viral envelope can give a virion a few distinct advantages over other capsid-only virions, such as protection from enzymes and certain chemicals. The proteins in it can include glycoproteins functioning as receptor molecules, allowing host cells to recognise and bind these virions, resulting in the possible uptake of the virion into the cell. Most enveloped viruses are dependent upon the envelope for infectivity. Download high resolution version (1725x1200, 473 KB)Source: US National Institute of Health (redrawn by User:Carl Henderson) URL: http://www. ... Download high resolution version (1725x1200, 473 KB)Source: US National Institute of Health (redrawn by User:Carl Henderson) URL: http://www. ... Species Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections). ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that encapsulate the cell. ... Many viruses (e. ... A glycoprotein is a macromolecule composed of a protein and a carbohydrate (an oligosaccharide). ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ...

Image Complex viruses
Diagram of a bacteriophage
Diagram of a bacteriophage
These viruses possess a capsid which is neither purely helical, nor purely icosahedral, and which may possess extra structures such as protein tails or a complex outer wall. Some bacteriophages have a complex structure consisting of an icosahedral head bound to a helical tail, the latter of which may have a hexagonal base plate with many protruding protein tail fibres.

The Poxviruses are large, complex viruses which have an unusual morphology. The viral genome is associated with proteins within a central disk structure known as a nucleoid. The nucleoid is surrounded by a membrane and two lateral bodies of unknown function. The virus has an outer envelope with a thick layer of protein studded over its surface. The whole particle is slightly pleiomorphic, ranging from ovoid to brick shape[citation needed]. Image File history File links Tevenphage. ... Image File history File links Tevenphage. ... ... Genera Subfamily Chordopoxvirinae    Orthopoxvirus    Parapoxvirus    Avipoxvirus    Capripoxvirus    Leporipoxvirus    Suipoxvirus    Molluscipoxvirus    Yatapoxvirus Subfamily Entomopoxvirinae    Entomopoxvirus A    Entomopoxvirus B    Entomopoxvirus C Poxviruses (members of the family Poxviridae) can infect as a family both vertebrate and invertebrate animals. ... The term morphology in biology refers to the outward appearance (shape, structure, colour, pattern) of an organism or taxon and its component parts. ... It has been suggested that Genophore be merged into this article or section. ... Pleomorphic literally means Varying Shapes. In oncology, it usually refers to one of the following types of tumors: Pleomorphic adenoma Pleomorphic xanthoastrocytoma This is a disambiguation page: a list of articles associated with the same title. ...

The range of sizes shown by viruses, relative to those of other organisms and biomolecules
The range of sizes shown by viruses, relative to those of other organisms and biomolecules

Image File history File links Relative_scale. ... Image File history File links Relative_scale. ... This article does not cite any references or sources. ...

Size

To put viral size into perspective, a medium sized virion next to a flea is roughly equivalent to a human next to a mountain twice the size of Mount Everest. Some filoviruses have a total length of up to 1400 nm, however their capsid diameters are only about 80 nm. The majority of viruses which have been studied have a capsid diameter between 10 and 300 nanometres. While most viruses are unable to be seen with a light microscope, some are as large or larger than the smallest bacteria and can be seen under high optical magnification. More commonly, both scanning and transmission electron microscopes are used to visualise virus particles. “Everest” redirects here. ... Genera Marburgvirus Ebolavirus Filoviruses are viruses belonging to the family Filoviridae, which is in the order Mononegavirales. ... A capsid is the outer shell of a virus. ... A nanometre (American spelling: nanometer) is 1. ... 1852 microscope Compound microscope made by John Cuff in 1750 A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... An electron microscope is a type of microscope that uses electrons to illuminate and create an image of a specimen. ...


A notable exception to the normal viral size range is the recently discovered mimivirus, with a diameter of 750 nm which is larger than a Mycoplasma bacterium.[10][11] They also hold the record for the largest viral genome size, possessing about 1000 genes (some bacteria only possess 400) on a genome approximately 1.2 megabases in length.[12] Their large genome also contains many genes which are conserved in both prokaryotic and eukaryotic genes.[13] The discovery of the virus has led many scientists to reconsider the controversial boundary between living organisms and viruses, which are currently considered as mere mobile genetic elements. Mimivirus is a viral genus containing a single identified species named Acanthamoeba polyphaga mimivirus (APMV). ... Species M. genitalium M. hominis M. pneumoniae etc. ... Megabase (Mb) is a unit of length for DNA fragments, equal to 1 million nucleotides. ... In biology, homology is any similarity between structures that is due to their shared ancestry. ...


Genome

Genomic diversity among viruses
Property Parameters
Nucleic acid
  • DNA
  • RNA
  • Both DNA and RNA
Shape
  • Linear
  • Circular
  • Segmented
Strandedness
  • Single-stranded
  • Double-stranded
  • Double-stranded with regions of single-strandedness
Sense
  • Positive sense (+)
  • Negative sense (-)
  • Ambisense (+/-)

An enormous variety of genomic structures can be seen among viral species; as a group they contain more structural genomic diversity than the entire kingdoms of either plants, animals, or bacteria[14]. Sense, when applied in a molecular biology context, is a general concept used to compare the polarity of nucleic acid molecules, particularly RNA, to other nucleic acid molecules. ...


Nucleic acid

A virus may employ either DNA or RNA as the nucleic acid. Rarely do they contain both, however cytomegalovirus is an exception to this, possessing a DNA core with several mRNA segments.[8] Plant viruses tend to have single-stranded RNA and bacteriophages tend to have double-stranded DNA.[8] Some virus species possess abnormal nucleotides, such as hydroxymethylcytosine instead of cytosine, as a normal part of their genome.[8] The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers that plays several important roles in the processes that translate genetic information from deoxyribonucleic acid (DNA) into protein products; RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes, forms vital portions... Species see text Cytomegalovirus (CMV) (from the Greek cyto-, cell, and -mega-, large) is a viral genus of the Herpesviruses group: in humans it is commonly known as human herpesvirus 5 (HHV-5). ... The interaction of mRNA in a eukaryote cell. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at...


Shape

Viral genomes may be circular, such as polyomaviruses, or linear, such as adenoviruses. The type of nucleic acid is irrelevant to the shape of the genome. Among RNA viruses, the genome may be divided up into separate parts within the virion, or segmented. All double-stranded RNA genomes, and some single-stranded RNA genomes, are segmented.[8] Each segment may code for one protein, and they are usually found together in one capsid. Not all segments are required to be in the same virion for the overall virus to be infectious, as demonstrated by the brome mosaic virus.[8] Species See text Polyomavirus is the sole genus of viruses within the family Polyomaviridae. ... Genera Mastadenovirus Aviadenovirus Atadenovirus Siadenovirus Adenoviruses are viruses of the family Adenoviridae. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... Brome mosaic virus (BMV) is a small (27 nm, 86S), positive-stranded, icosahedral RNA plant virus belonging to the family Bromoviridae of the alphavirus-like superfamily (Francki, 1985). ...


Strandedness

A viral genome, irrespective of nucleic acid type, may be either single-stranded or double-stranded. Single-stranded genomes consist of an unpaired nucleic acid, analogous to one-half of a ladder split down the middle. Double-stranded genomes consist of 2 complimentary paired nucleic acids, analogous to a ladder. Some viruses, such as those belonging to the Hepadnaviridae, contain a genome which is partially double-stranded and partially single-stranded.[14] Genera Orthohepadnavirus Avihepadnavirus Hepadnaviruses are the viruses in the family Hepadnaviridae. ...


Sense

For viruses with RNA as their nucleic acid, the strands are said to be either positive-sense (also called plus-strand) or negative-sense (also called minus-strand) depending on whether it is complementary to viral mRNA. Positive-sense viral RNA is identical to viral mRNA and thus can be immediately translated by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase before translation. DNA nomenclature is similar to RNA nomenclature, in that the coding strand for the viral mRNA is complementary to it (-), and the non-coding strand is a copy of it (+). Sense, when applied in a molecular biology context, is a general concept used to compare the polarity of nucleic acid molecules, particularly RNA, to other nucleic acid molecules. ... Sense, when applied in a molecular biology context, is a general concept used to compare the polarity of nucleic acid molecules, particularly RNA, to other nucleic acid molecules. ... Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ... This article does not cite any references or sources. ...


Genome size

Genome size in terms of the weight of nucleotides varies between species. The smallest genomes code for only four proteins and weigh about 106 daltons, while the largest weigh about 108 daltons and code for over one hundred proteins.[8] RNA viruses generally have smaller genome sizes than DNA viruses due to a higher error-rate when replicating, resulting in a maximum upper size limit. Beyond this limit, too many errors in the genome when replicating render the virus useless or uncompetitive. In contrast, DNA viruses generally have larger genomes due to the high fidelity of their replication enzymes.[14] A nucleotide is an organic molecule consisting of a heterocyclic nucleobase (a purine or a pyrimidine), a pentose sugar (deoxyribose in DNA or ribose in RNA), and a phosphate or polyphosphate group. ... The unified atomic mass unit (u), or Dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... A DNA virus is a virus belonging to either Group I or Group II of the Baltimore classification system for viruses. ...


Replication

Viral populations do not grow through cell division, because they are acellular; instead, they use the machinery and metabolism of a host cell to produce multiple copies of themselves. A virus can still cause degenerative effects within a cell without causing its death; collectively these are termed cytopathic effects. Released virions can be passed between hosts through either direct contact, often via body fluids, or through a vector. In aqueous environments, viruses float free in the water. This does not adequately cite its references or sources. ... Bodily fluids are fluids, which are generally excreted or secreted from the human body. ... In epidemiology, a vector is an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another. ...


Lytic or lysogenic

Viruses may have a lytic or a lysogenic cycle, with some viruses capable of carrying out both.[8] The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle. ... Lysogeny, or the lysogenic cycle, is one of two methods of viral reproduction (the lytic cycle is the other). ...


Lytic cycle

Main article: Lytic cycle

In the lytic cycle, characteristic of virulent phages such as the T4 phage, host cells will be induced by the virus to begin manufacturing the proteins necessary for virus reproduction. As well as proteins, the virus must also direct the replication of new genomes, the technique used for this varies greatly between virus species but depends heavily on the genome type. The final viral product is assembled spontaneously, though it may be aided by molecular chaperones. After the genome has been replicated and the new capsid assembled, the virus causes the cell to be broken open (lysed) to release the virus particles. Some viruses do not lyse the cell but instead exit the cell via the cell membrane in a process known as exocytosis, taking a small portion of the membrane with them as a viral envelope. As soon as the cell is destroyed the viruses have to find a new host. The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle. ... Enterobacteria phage T4 is a phage that infects E. coli bacteria. ... In biology, chaperones are proteins whose function is to assist other proteins in achieving proper folding. ... The cell membrane (also called the plasma membrane, plasmalemma or phospholipid bilayer) is a semipermeable lipid bilayer common to all living cells. ... This page is currently under construction. ...


Lysogenic cycle

Main article: Lysogenic cycle

In contrast, the lysogenic cycle does not result in immediate lysing of the host cell, instead the viral genome integrates into the host DNA and replicates along with it. The virus remains dormant but after the host cell has replicated several times, or if environmental conditions permit it, the virus will become active and enter the lytic phase. The lysogenic cycle allows the host cell to continue to survive and reproduce, and the virus is passed on to all of the cell’s offspring. Lysogeny, or the lysogenic cycle, is one of two methods of viral reproduction (the lytic cycle is the other). ...

A falsely coloured electron micrograph of multiple bacteriophages

Image File history File links The use of this file has been permitted by the owner. ... Image File history File links The use of this file has been permitted by the owner. ... A bacteriophage (from bacteria and Greek phagein, to eat) is a virus that infects bacteria. ...

Bacteriophages

Bacteriophages infect specific bacteria by binding to surface receptor molecules and then enter the cell. Within a short amount of time, sometimes just minutes, bacterial polymerase starts translating viral mRNA into protein. These proteins go on to become either new virions within the cell, helper proteins which help assembly of new virions, or proteins involved in cell lysis. Viral enzymes aid in the breakdown of the cell membrane, and in the case of the T4 phage, in just over twenty minutes after injection over three hundred phages will be released. A bacteriophage (from bacteria and Greek phagein, to eat) is a virus that infects bacteria. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... ITaq DNA polymerase A polymerase (EC 2. ... Lysis (Greek lusis from luein = to separate) refers to the death of a cell by bursting, often by viral or osmotic mechanisms that compromise the integrity of the cellular membrane. ... Enterobacteria phage T4 is a phage that infects E. coli bacteria. ...


DNA viruses

Animal DNA viruses, such as herpesviruses, enter the host via endocytosis, the process by which cells take in material from the external environment. Frequently after a chance collision with an appropriate surface receptor on a cell, the virus penetrates the cell, the viral genome is released from the capsid and host polymerases begin transcribing viral mRNA. New virions are assembled and released either by cell lysis or by budding off the cell membrane. A DNA virus is a virus belonging to either Group I or Group II of the Baltimore classification system for viruses. ... Genera Subfamily Alphaherpesvirinae    Simplexvirus    Varicellovirus    Mardivirus    Iltovirus Subfamily Betaherpesvirinae    Cytomegalovirus    Muromegalovirus    Roseolovirus Subfamily Gammaherpesvirinae    Lymphocryptovirus    Rhadinovirus Unassigned    Ictalurivirus The Herpesviridae are a family of DNA viruses that cause diseases in humans and animals. ... It has been suggested that Endocytic cycle be merged into this article or section. ...


RNA viruses

Animal RNA viruses can be placed into about four different groups depending on their mode of replication. The polarity of the RNA largely determines the replicative mechanism, as well as whether the genetic material is single-stranded or double-stranded. Some RNA viruses are actually DNA based but use an RNA-intermediate to replicate. RNA viruses are heavily dependent upon virally encoded RNA replicase to create copies of their genomes. An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... Sense, when applied in a molecular biology context, is a general concept used to compare the polarity of nucleic acid molecules, particularly RNA, to other nucleic acid molecules. ... An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ... RNA replicase is a polymerase enzyme that catalyzes the self-replication of single-stranded RNA. it is RNA dependent RNA plwhich is not haVING PRROFREEDING ACTIVITY. THIS IS ANOTHER EXTENSION IN THE CENTRADOGMA. IT IS MADE UP OF THREE SUBUNIT. Categories: | ...


Reverse transcribing viruses

Reverse transcribing viruses are viruses that replicate using reverse transcription, which is the formation of DNA from an RNA template. Those viruses containing RNA genomes use a DNA intermediate to replicate, whereas those containing DNA genomes use an RNA intermediate during genome replication. Both types of reverse transcribing viruses use the reverse transcriptase enzyme to carry out the nucleic acid conversion. A reverse transcribing virus is any virus which replicates using reverse transcription, the formation of DNA from an RNA template. ... In biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzyme that transcribes single-stranded RNA into double-stranded DNA. Normal transcription involves the synthesis of RNA from DNA, hence reverse transcription is the reverse of this. ...


Lifeform debate

Multiple rotavirus virions
Multiple rotavirus virions

Argument continues over whether viruses are truly alive. According to the United States Code, they are considered microorganisms in the sense of biological weaponry and malicious use. Scientists, however, are divided. Things become complicated as they look at simple viruses, viroids and prions. Viruses resemble other organisms in that they possess nucleic acid, and can respond - in infected cells - to their environment in a limited fashion. They can also reproduce by creating multiple copies of themselves through simple self-assembly. Image File history File links Rotavirus_TEM_B82-0337_lores. ... Image File history File links Rotavirus_TEM_B82-0337_lores. ... This article or section does not adequately cite its references or sources. ... The United States Code (U.S.C.) is a compilation and codification of the general and permanent federal law of the United States. ... A cluster of Escherichia coli bacteria magnified 10,000 times. ... Viroids are infectious agents that consist of single-stranded RNA. They are much smaller and simpler than viruses and lack the protein cover that is typical for viruses. ... For the bird called a prion, see Prion (bird) Prions - short for proteinaceous infectious particle - are infectious self-reproducing protein structures. ...


Viruses do not have a cell structure, regarded as the basic unit of life. Additionally, although they reproduce, they do not metabolise on their own and therefore require a host cell to replicate and synthesise new products. Bacterial species such as Rickettsia and Chlamydia, while living organisms, are even unable to reproduce outside of a host cell. Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Species Rickettsia felis Rickettsia prowazekii Rickettsia rickettsii Rickettsia typhi Rickettsia conorii Rickettsia africae etc. ... Chlamydia is a common term for infection with any bacterium belonging to the phylum Chlamydiae. ...


An argument can be made that all accepted forms of life use cell division to reproduce, whereas all viruses spontaneously assemble within cells. The comparison is drawn between viral self-assembly and the autonomous growth of non-living crystals. Virus self-assembly within host cells also has implications for the study of the origin of life, as it lends credence to the hypothesis that life could have started as self-assembling organic molecules[citation needed]. This does not adequately cite its references or sources. ... Frost crystallization on a shrub. ... This article does not adequately cite its references or sources. ...


If viruses are considered alive, then the criteria specifying life will have been permanently changed, leading scientists to question what the basic prerequisite of life is. The standards required to call something artificially alive would be reduced and the prospect of creating artificial life would be enhanced. If viruses were said to be alive, the question could follow of whether even smaller infectious particles, such as viroids and prions, are alive. Artificial Life, (commonly Alife or alife) is a field of study and art form that examines systems related to life, its processes and its evolution through simulations using computer models, robotics, and biochemistry [1] (called soft, hard, and wet approaches respectively[2]). Artificial life complements traditional Biology by trying to... Families Pospiviroidae Avsunviroidae Viroids are plant pathogens that consist of a short stretch (a few hundred nucleobases) of highly complementary, circular, single-stranded RNA without the protein coat that is typical for viruses. ... A prion (IPA: [1] ) — short for proteinaceous infectious particle (-on by analogy to virion) — is a type of infectious agent composed only of protein. ...


Viruses and disease

For more examples of diseases caused by viruses see List of infectious diseases

Examples of common human diseases caused by viruses include the common cold, the flu, chickenpox and cold sores. Many serious diseases such as Ebola, AIDS, avian flu and SARS are also caused by viruses. The relative ability of viruses to cause disease is described in terms of virulence. Other diseases are under investigation as to whether they too have a virus as the causative agent, such as the possible connection between Human Herpesvirus Six (HHV6) and neurological diseases such as multiple sclerosis and chronic fatigue syndrome. Recently it was also shown that cervical cancer is partially caused by papillomavirus, representing evidence in humans of a link existing between cancer and an infective agent.[15] There is current controversy over whether the borna virus, previously thought of as causing neurological disease in horses, could be responsible for psychiatric illness in humans.[16] Human infectious diseases grouped by causative agent and alphabetically arranged. ... Fiona, often known as the The Maher Man, is a viral infectious disease of the upper respiratory system (nose and throat). ... Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by an RNA virus of the family Orthomyxoviridae (the influenza viruses). ... South Park episode, see Chickenpox (South Park episode). ... The Herpes simplex virus infection (common names: herpes, cold sores) is a common, contagious, incurable, and in some cases sexually transmitted disease caused by a double-stranded DNA virus. ... Ebola is both the common term used to describe a group of viruses belonging to genus Ebolavirus, family Filoviridae, and the common name for the disease which they cause, Ebola hemorrhagic fever. ... Acquired Immune Deficiency Syndrome or acquired immunodeficiency syndrome (AIDS or Aids) is a collection of symptoms and infections resulting from the specific damage to the immune system caused by the human immunodeficiency virus (HIV). ... For the current concern about the transmission of an avian flu to humans see Transmission and infection of H5N1. ... Sars may refer to any of the following: Severe acute respiratory syndrome, commonly abbreviated as SARS Michael Sars, a Norwegian biologist, father of Georg Sars Georg Sars, a Norwegian biologist, son of Michael Sars Special Administrative Regions, commonly abbreviated as SARs Sars, Perm Krai, an urban settlement in Perm Krai... Virulence refers to the degree of pathogenicity of a microbe, or in other words the relative ability of a microbe to cause disease. ... Human Herpesvirus Six (HHV6) is one of the eight known members of the human herpesvirus family. ... Chronic fatigue syndrome (CFS) is one of several names given to a poorly understood, highly debilitating disorder of uncertain cause, which is thought to affect approximately 4 per 1,000 adults[1] in the United States and other countries, and a smaller fraction of children. ... Species See text Papillomaviruses are viruses that commonly cause warts. ... The Borna disease virus is the causative agent of borna disease in horses and other animals. ... Neurology is a branch of medicine dealing with disorders of the nervous system. ... Psychiatry is a branch of medicine dealing with the prevention, assessment, diagnosis, treatment, and rehabilitation of the mind and mental illness. ...


Viruses have many different mechanisms by which they produce disease in an organism, which largely depends on the species. Mechanisms at the cellular level primarily include cell lysis, the breaking open and subsequent death of the cell. In multicellular organisms, if enough cells die the whole organism will start to suffer the effects. Although many viruses result in the disruption of healthy homeostasis, resulting in disease, they may also exist relatively harmlessly within an organism. An example would include the ability of the herpes simplex virus, which cause coldsores, to remain in a dormant state within the human body. Lysis (Greek lusis from luein = to separate) refers to the death of a cell by bursting, often by viral or osmotic mechanisms that compromise the integrity of the cellular membrane. ... Wild-type Caenorhabditis elegans hermaphrodite stained to highlight the nuclei of all cells Multicellular organisms are organisms consisting of more than one cell, and having differentiated cells that perform specialized functions. ... Homeostasis is the property of either an open system or a closed system,[1] especially a living organism, to regulate its internal environment to maintain a stable, constant condition. ... Species Herpes simplex virus 1 (HSV-1) Herpes simplex virus 2 (HSV-2) This article is about the virus. ... The herpes simplex virus (HSV) (also known as Cold Sore, Night Fever, or Fever Blister) is a virus that manifests itself in two common viral infections, each marked by painful, watery blisters in the skin or mucous membranes (such as the mouth or lips) or on the genitals. ...


Epidemics

The Ebola virus
The Ebola virus
For more details on this topic, see List of epidemics.

A number of highly lethal viral pathogens are members of the Filoviridae. Filoviruses are filament-like viruses that cause viral hemorrhagic fever, and include the Ebola and Marburg viruses. The Marburg virus attracted widespread press attention in April 2005 for an outbreak in Angola. Beginning in October 2004 and continuing into 2005, the outbreak was the world's worst epidemic of any kind of viral hemorrhagic fever.[17] Image File history File links Ebola_Virus_TEM_PHIL_1832_lores. ... Image File history File links Ebola_Virus_TEM_PHIL_1832_lores. ... Ebola is both the common term used to describe a group of viruses belonging to genus Ebolavirus, family Filoviridae, and the common name for the disease which they cause, Ebola hemorrhagic fever. ... Image File history File links Marburg_virions_TEM_275_lores. ... Image File history File links Marburg_virions_TEM_275_lores. ... The Marburg virus is the causative agent of Marburg hemorrhagic fever. ... This is a list of major epidemics. ... Genera Marburgvirus Ebolavirus Filoviruses are viruses belonging to the family Filoviridae, which is in the order Mononegavirales. ... Viral hemorrhagic fevers (VHFs) are a group of illnesses that are caused by several distinct families of viruses: Arenavirus, Filoviridae, Bunyaviridae and Flavivirus. ... Ebola is both the common term used to describe a group of viruses belonging to genus Ebolavirus, family Filoviridae, and the common name for the disease which they cause, Ebola hemorrhagic fever. ... The Marburg virus is the causative agent of Marburg hemorrhagic fever. ...


Native American populations were devastated by contagious diseases, particularly smallpox, brought to the Americas by European colonists. It is unclear how many Native Americans were killed by foreign diseases after the arrival of Columbus in the Americas, but the numbers have been estimated to be close to 70% of the indigenous population.[18] The damage done by this disease may have significantly aided European attempts to displace or conquer the native population. Native Americans redirects here. ... Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. ...


Detection, purification and diagnosis

In the laboratory, several techniques for growing and detecting viruses exist. Purification of viral particles can be achieved using differential centrifugation, isopycnic centrifugation, precipitation with ammonium sulfate or ethylene glycol, and removal of cell components from a homogenised cell mixture using organic solvents or enzymes to leave the virus particles in solution. Differential centrifugation is a procedure in which the homogenate is subjected to repeated centrifugations each time increasing the centrifugal force. ... Isopycnic centrifugation or equilibrium centrifugation is a process used to isolate nucleic acids such as DNA. To begin the analysis a mixture of cesium chloride and DNA is placed in a centrifuge for several hours at high speed to generate a force of about 10^5 x g (earths... Ammonium sulphate, [NH4]2[SO4] contains 21% nitrogen as ammonia and 24% sulfur as sulfate. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...


Assays to detect and quantify viruses include:

  • Hemagglutination assays, which quantitatively measure how many virus particles are in a solution of red blood cells by the amount of agglutination the viruses cause between them. This occurs as many viruses are able to bind to the surface of one or more red blood cells.
  • Direct counts using an electron microscope. A dilute mixture of virus particles and beads of known size are sprayed onto a special sheet and examined under high magnification. The virions are counted and the number extrapolated to estimate the number of virions in the undiluted mixture.
  • Plaque assays involve growing a thin layer of host cells onto a culture dish and adding a dilute mixture of virions onto it. The virions will infect and kill the cells they land on, producing holes in the cell layer known as plaques. The number of plaques can be counted and the number of virions estimated from it.

Detection and subsequent isolation of new viruses from patients is a specialised laboratory subject. Normally it requires the use of large facilities, expensive equipment, and trained specialists such as technicians, molecular biologists, and virologists. Often, this effort is undertaken by state and national governments and shared internationally through organizations like the World Health Organization. Image File history File links Plaque_assay_macro. ... Image File history File links Plaque_assay_macro. ... A viral plaque is a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium (e. ... An assay is a procedure where the concentration of a component part of a mixture is determined. ... The Hemagglutination Assay (HA) is a quantification of viruses. ... Human red blood cells Red blood cells are the most common type of blood cell and are the vertebrate bodys principal means of delivering oxygen to body tissues via the blood. ... Agglutination is the clumping of particles. ... An electron microscope is a type of microscope that uses electrons to illuminate and create an image of a specimen. ... A viral plaque is a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium (e. ... Molecular biology is the study of biology at a molecular level. ... Virology is the study of viruses and their properties. ... The World Health Organization (WHO) is a specialized agency of the United Nations (UN) that acts as a coordinating authority on international public health. ...


Prevention and treatment

Because viruses use the machinery of a host cell to reproduce and also reside within them, they are difficult to eliminate without killing the host cell. The most effective medical approaches to viral diseases so far are vaccinations to provide resistance to infection, and drugs which treat the symptoms of viral infections. Patients often ask for, and physicians often prescribe, antibiotics. These are useless against viruses, and their misuse against viral infections is one of the causes of antibiotic resistance in bacteria. However, in life-threatening situations the prudent course of action is to begin a course of antibiotic treatment while waiting for test results to determine whether the patient's symptoms are caused by a virus or a bacterial infection[citation needed]. Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... A vial of the vaccine against influenza. ... This article does not cite any references or sources. ... Staphylococcus aureus - Antibiotics test plate. ... Antibiotic resistance is the ability of a micro-organism to withstand the effects of an antibiotic. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ...


Potential uses in therapy

Virotherapy uses viruses as vectors to treat various diseases, as they can specifically target cells and DNA. It shows promise in the treatment of cancer and as a method for gene therapy.[citation needed] Eastern European doctors have used phage therapy as an alternative to antibiotics for some time and interest in this approach is increasing, due to the high level of antibiotic resistance now found in some pathogenic bacteria.[19] // Surgery; Radiotherapy; Chemotherapy - the conventional triumvirate in our anti-cancer armoury. ... A 3D rendering showing T4 type bacteriophages landing on a bacterium to inject genetic material. ... Antibiotic resistance is the ability of a micro-organism to withstand the effects of an antibiotic. ...


Applications

Image File history File links Download high resolution version (724x1000, 690 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Virus ... Image File history File links Download high resolution version (724x1000, 690 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Virus ... A section of a cell of Bacillus subtilis, taken with a Tecnai T-12 TEM. The scale bar is 200nm. ... A micrograph is a photograph or similar image taken through a microscope or similar device to show a magnified image of an item. ... This article is about the virus. ...

Life sciences

Viruses are important to the study of molecular and cellular biology as they provide simple systems that can be used to manipulate and investigate the functions of cells. The study and use of viruses have provided valuable information about many aspects of cell biology. For example, viruses have simplified the study of genetics and helped human understanding of the basic mechanisms of molecular genetics, such as DNA replication, transcription, RNA processing, translation, protein transport, and immunology. Molecular biology is the study of biology at a molecular level. ... Cell biology (cellular biology) is an academic discipline which studies the physiological properties of cells, as well as their behaviours, interactions, and environment; this is done both on a microscopic and molecular level. ... This article is about the general scientific term. ... Molecular genetics is the field of biology which studies the structure and function of genes at a molecular level. ... It has been suggested that DNA replicate, Replisome, Replication fork, Lagging strand, Leading strand be merged into this article or section. ... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... The term RNA editing describes those molecular processes in which the information content is altered in a RNA molecule through a chemical change in the base makeup. ... Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. ...


Geneticists regularly use viruses as vectors to introduce genes into cells that they are studying. This is useful for making the cell produce a foreign substance, or to study the effect of introducing a new gene into the genome. In similar fashion, virotherapy uses viruses as vectors to treat various diseases, as they can specifically target cells and DNA. It shows promising use in the treatment of cancer and in gene therapy. This article is about the general scientific term. ... In epidemiology, a vector is an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another. ... // Surgery; Radiotherapy; Chemotherapy - the conventional triumvirate in our anti-cancer armoury. ... Gene therapy is the insertion of genes into an individuals cells and tissues to treat a disease, and hereditary diseases in which a defective mutant allele is replaced with a functional one. ...


Materials science and nanotechnology

Current trends in nanotechnology promise to make much more versatile use of viruses. From the viewpoint of a materials scientist, viruses can be regarded as organic nanoparticles[citation needed]. Their surface carries specific tools designed to cross the barriers of their host cells. The size and shape of viruses, and the number and nature of the functional groups on their surface, is precisely defined. As such, viruses are commonly used in materials science as scaffolds for covalently linked surface modifications. A particular quality of viruses is that they can be tailored by directed evolution. The powerful techniques developed by life sciences are becoming the basis of engineering approaches towards nanomaterials, opening a wide range of applications far beyond biology and medicine.[20]


In April 2006 scientists at the Massachusetts Institute of Technology (MIT) created nanoscale metallic wires using a genetically-modified virus.[21] The MIT team was able to use the virus to create a working battery with an energy density up to three times more than current materials. The potential exists for this technology to be used in liquid crystals, solar cells, fuel cells, and other electronics in the future. The Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. ... Buckminsterfullerene C60, also known as the buckyball, is the simplest of the carbon structures known as fullerenes. ... An iconic image of genetic engineering; this autoluminograph from 1986 of a glowing transgenic tobacco plant bearing the luciferase gene, illustrating the possibilities of genetic engineering. ... Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ... Energy density is the amount of energy stored in a given system or region of space per unit volume or per unit mass, depending on the context. ... Schlieren texture of Liquid Crystal nematic phase Liquid crystals are substances that exhibit a phase of matter that has properties between those of a conventional liquid, and those of a solid crystal. ... A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ...

The reconstructed 1918 influenza virus
The reconstructed 1918 influenza virus

Image File history File links Reconstructed_Spanish_Flu_Virus. ... Image File history File links Reconstructed_Spanish_Flu_Virus. ... The Spanish Flu Pandemic, also known as , , or the 1918 flu, was a pandemic caused by an unusually severe and deadly strain of the subtype H1N1 of the species Influenza A virus. ...

Weapons

For more details on this topic, see Biological warfare.

The ability of viruses to cause devastating epidemics in human societies has led to the concern that viruses could be weaponized for biological warfare. Further concern was raised by the successful recreation of the infamous 1918 influenza virus in a laboratory.[22] The smallpox virus devastated numerous societies throughout history before its eradication. It currently exists in several secure laboratories in the world, and fears that it may be used as a weapon are not totally unfounded. The modern global human population has almost no established resistance to smallpox; if it were to be released, a massive loss of life could be sustained before the virus is brought under control. For the use of biological agents by terrorists, see bioterrorism. ... In epidemiology, an epidemic (from [[Latin language] epi- upon + demos people) is a disease that appears as new cases in a given human population, during a given period, at a rate that substantially exceeds what is expected, based on recent experience (the number of new cases in the population during... For the use of biological agents by terrorists, see bioterrorism. ... Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. ...


Etymology

The word is from the Latin virus referring to poison and other noxious substances, first used in English in 1392.[23] Virulent, from Latin virulentus "poisonous" dates to 1400.[24] A meaning of "agent that causes infectious disease" is first recorded in 1728,[23] before the discovery of viruses by the Russian-Ukrainian biologist Dmitry Ivanovsky in 1892. The adjective viral dates to 1948.[25] Today, virus is used to describe the biological viruses discussed above and also as a metaphor for other parasitically-reproducing things, such as memes or computer viruses (since 1972).[24] The neologism virion or viron is used to refer to a single infective viral particle. For other uses, see Latin (disambiguation). ... The skull and crossbones symbol (Jolly Roger) traditionally used to label a poisonous substance. ... A biologist is a scientist devoted to and producing results in biology through the study of organisms. ... Dmitry Iosifovich Ivanovsky (1864-1920), a Russian biologist who was the first to discover viruses (1892). ... This article is about metaphor in literature and rhetoric. ... For other uses, see Meme (disambiguation). ... A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. ... A neologism (Greek νεολογισμός [neologismos], from νέος [neos] new + λόγος [logos] word, speech, discourse + suffix -ισμός [-ismos] -ism) is a word, term, or phrase which has been recently created (coined) — often to apply to new concepts, to synthesize pre-existing concepts, or to make older terminology sound more contemporary. ...


The Latin word is from a Proto-Indo-European root *weis- "to melt away, to flow," used of foul or malodorous fluids. It is a cognate of Sanskrit viṣh "poison", Avestan viš- "poison", Greek ios "poison", Old Church Slavonic višnja "cherry", Old Irish fi "poison", Welsh gwy "fluid"; Latin viscum (see viscous) "sticky substance" is also from the same root. The Proto-Indo-European language (PIE) is the hypothetical common ancestor of the Indo-European languages, spoken by the Proto-Indo-Europeans. ... The Sanskrit language ( , for short ) is a classical language of India, a liturgical language of Hinduism, Buddhism, Sikhism, and Jainism, and one of the 23 official languages of India. ... Yasna 28. ... Old Church Slavonic (Old Bulgarian or Old Slavic) is the first literary Slavic language, developed from the Slavic dialect of Thessaloniki (Solun) by the 9th century Byzantine missionaries, Saints Cyril and Methodius. ... Old Irish is the name given to the oldest form of the Irish language which can be more or less fully reconstructed from extant sources. ... Welsh redirects here, and this article describes the Welsh language. ... Viscosity is a measure of the resistance of a fluid to deformation under shear stress. ...


The English plural form of virus is viruses. No reputable dictionary gives any other form, including such "reconstructed" Latin plural forms as viri (which actually means men), and no plural form appears in the Latin corpus (See plural of virus). Virus does not have a traditional Latin plural because its original sense, poison is a mass noun like the English word furniture, and, as pointed out above, English use of virus to denote the agent of a disease predates the discovery that these agents are microscopic parasites and thus in principle countable. Look up virus in Wiktionary, the free dictionary. ... It has been suggested that Count noun be merged into this article or section. ...


Philosophy

Viruses have attracted attention of philosophers and critics because of their position at the margins of life and their unique method of propagation. Susan Sontag argues that viruses have been used detrimentally as metaphors for social phenomena.[26] Gilles Deleuze and Félix Guattari use the virus as an example of rhizomatic being because of its nomadic movement through host organisms. They note that viruses can be responsible for "aparallel evolution", which they see as disruptive to arborescent phylogentic trees. [27] Susan Sontag (January 16, 1933 – December 28, 2004) was a well-known American essayist, novelist, intellectual, filmmaker, and activist. ... Gilles Deleuze (IPA: ), (January 18, 1925 – November 4, 1995) was a French philosopher of the late 20th century. ... Pierre-Félix Guattari (1930 - 1992) was a French pioneer of institutional psychotherapy, as well as the founder of both Schizoanalysis and the science of Ecosophy. ... The term rhizome has been used by Carl Jung as a metaphor, and by Gilles Deleuze as a concept, and refers to the botanical rhizome. ... Horizontal gene transfer (HGT), also Lateral gene transfer (LGT), is any process in which an organism transfers genetic material to another cell that is not its offspring. ...


See also

Wikimedia Commons has media related to:
Virus
Look up Virus in
Wiktionary, the free dictionary.

Image File history File links Wikibooks-logo-en. ... Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ... This is a list of biological viruses, and types of viruses. ... A nanobe Nanobes are tiny filamental structures first found in some rocks and sediments. ... Structures found on meteorite fragment ALH84001 Nanobacteria (sometimes Nannobacteria ) are claimed to be cell-walled microorganisms with a diameter well below the generally accepted lower limit (about 0. ... A provirus is a retrovirus that has integrated itself into the DNA of a host cell. ... The word transduction has several meanings: In developmental psychology, transduction is reasoning from specific cases to specific cases, typically employed by children. ... A bioaerosol is a biological aerosol. ... An oncolytic virus is a virus used to treat cancer due to their ability to specifically infect cancer cells, while leaving normal cells unharmed. ...

Footnotes

  1. ^ http://school.discovery.com/lessonplans/programs/understandingviruses/
  2. ^ http://www.tulane.edu/~dmsander/garryfavwebfaq.html
  3. ^ http://library.thinkquest.org/CR0212089/virus.htm
  4. ^ Lewis R (2000). "Polio Eradication Goal Extended". The Scientist 14 (24): 12. 
  5. ^ Behbehani AM (1983). "The smallpox story: life and death of an old disease". Microbiol Rev 47 (4): 455-509. PMID 6319980. 
  6. ^ Smallpox eradication: destruction of variola virus stocks. WHO: 52nd World Health Assembly. Retrieved on 2006-09-23.
  7. ^ Horzinek MC (1997). "The birth of virology". Antonie van Leeuwenhoek 71: 15–20. DOI:10.1023/A:1000197505492. 
  8. ^ a b c d e f g h i Prescott, L (1993). Microbiology. Wm. C. Brown Publishers. 0-697-01372-3. 
  9. ^ Virus triangulation numbers via Internet Archive. Retrieved on 2006-04-05.
  10. ^ Robertson J, Gomersall M, Gill P (1975). "Mycoplasma hominis: growth, reproduction, and isolation of small viable cells". J Bacteriol. 124 (2): 1007 – 18. PMID 1102522. 
  11. ^ Claverie J, Ogata H, Audic S, Abergel C, Suhre K, Fournier P (2006). "Mimivirus and the emerging concept of "giant" virus". Virus Res 117 (1): 133-44. PMID 16469402. 
  12. ^ Raoult D, Audic S, Robert C, et al (2004). "The 1.2-megabase genome sequence of Mimivirus". Science 306 (5700): 1344-50. PMID 15486256. 
  13. ^ Mimiviridae genome. Stanford University. Retrieved on 2007-04-05.
  14. ^ a b c Flinth; et al. (2004). Principles of Virology, 2nd edn, ASM Press, New York. 1-55581-259-7. 
  15. ^ "Human Papilloma Virus", BBC News, 1999-08-26. Retrieved on 2007-03-17. 
  16. ^ Chen C, Chiu Y, Wei F, Koong F, Liu H, Shaw C, Hwu H, Hsiao K (1999). "High seroprevalence of Borna virus infection in schizophrenic patients, family members and mental health workers in Taiwan". Mol Psychiatry 4 (1): 33-8. PMID 10089006. 
  17. ^ Marburg outbreak worst recorded. BBC News (2005-03-31). Retrieved on 2007-04-05.
  18. ^ Smallpox epidemic ravages Native Americans on the northwest coast of North America in the 1770s. HistoryLink.org. Retrieved on 2007-04-05.
  19. ^ Matsuzaki S, Rashel M, Uchiyama J, et al (2005). "Bacteriophage therapy: a revitalized therapy against bacterial infectious diseases". J. Infect. Chemother. 11 (5): 211-9. DOI:10.1007/s10156-005-0408-9. PMID 16258815. 
  20. ^ Fischlechner M, Donath E (2007). "Viruses as Building Blocks for Materials and Devices". Angewandte Chemie International Edition. DOI:10.1002/anie.200603445. 
  21. ^ Researchers build tiny batteries with viruses. MIT News Office. Retrieved on 2007-04-05.
  22. ^ Researchers Reconstruct 1918 Pandemic Influenza Virus; Effort Designed to Advance Preparedness. Centers for Disease Control. Retrieved on 2007-04-05.
  23. ^ a b virus. The Online Etymology Dictionary. Retrieved on 2007-07-16.
  24. ^ a b virulent, a.. The Oxford English Dictionary - Online. Retrieved on 2007-07-16.
  25. ^ viral, a.. The Oxford English Dictionary - Online. Retrieved on 2007-07-16.
  26. ^ Sontag, Susan (1978). Illness as Metaphor. Farrar Straus & Giroux.
  27. ^ Deleuze, Gilles and Félix Guattari (1987) [1980]. A Thousand Plateaus. University of Minnesota Press.

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 266th day of the year (267th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 197th day of the year (198th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 197th day of the year (198th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 197th day of the year (198th in leap years) in the Gregorian calendar. ... Susan Sontag (January 16, 1933 – December 28, 2004) was a well-known American essayist, novelist, intellectual, filmmaker, and activist. ... Illness as Metaphor is a nonfiction work written by Susan Sontag and published in 1978. ... Gilles Deleuze (IPA: ), (January 18, 1925 – November 4, 1995) was a French philosopher of the late 20th century. ... Pierre-Félix Guattari (1930 - 1992) was a French pioneer of institutional psychotherapy, as well as the founder of both Schizoanalysis and the science of Ecosophy. ... A Thousand Plateaus (1980) is a book by the French philosopher Gilles Deleuze and psychoanalyst Félix Guattari. ...

References

National Center for Biotechnology Information logo The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...

External links

86.3.154.25 00:15, 9 September 2007 (UTC) There are very few or no other articles that link to this one. ...


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