Preface 01 head Thief 02 Death Masters 03 to find the first 04 the call of the Imperial Palace 05 scared to death 06 "She" 07 head sold to know what's what Princess 08 09 common enemies of man 10 invincible army 11 palace
An analog of bacteria is still small, there is no cell structure, only the proliferation of living cells of microorganisms. Composed of proteins and nucleic acids. Most use the electron microscope can be observed. Divided into categories according to their host animal viruses, plant viruses and bacterial virus (phage). And the plants and animals can cause disease. Parasitic insect viruses in arthropods, can be used for biological control.
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bìng dú
指 an ordinary microscope can not see the Zuixiao bacteria, and are a kind of inheritance, variation, coexistence and interference phenomena of life such as the Ganran body, in a certain living proliferate within the cell death or Sun Hai Zao Cheng
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小儿麻痹病毒
Polio virus
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病原体
病毒 病原体
病毒 病原体
Smaller than bacteria, can be observed with electron microscopy of pathogens. Bacteria through the filter device, so called viral.
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比喻有害的思想
Metaphor of harmful ideas. Such as: a young individualism virus contamination, they often only see their personal interests, can not see the national interest.
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指梅毒
病毒 指梅毒
Refer to syphilis. Lu Xun's "grave we do Father": "Because his father is not seized, congenital got the virus, not a man of the way."
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Overview
Is a class of individual small, non-intact cell structure, containing a single nucleic acid (dna or rna) type, to be parasitic in living cells and the replication of non-cell organisms. Originally referred to an animal source of the toxin. "Virus" derives from the Latin word. Virus can proliferation, genetic and evolution, which has the basic characteristics of life. Its main features are: ① a nucleic acid that contains a single (dna or rna) genomes and protein shell, there is no cell structure; ② in infected cells at the same time or shortly release its nucleic acid, and then the way to the proliferation of DNA replication, rather than two proliferation means division; ③ strict intracellular parasites. Form of the virus (1) spherical virus; (2) baculovirus; (3) brick-shaped virus; (4) enveloped spherical virus; (5) has a spherical head of the virus; (6) sealed in the body of the insect virus that contains . The size of the virus Larger diameter of 300-450 nm virus, the smaller the diameter of only 18-22 nm virus Composition of the virus Virus is mainly formed by the nucleic acid and protein coat. Viral replication process is called replication cycle. It can be divided into five consecutive stages: adsorption, penetration, uncoating, viral macromolecular synthesis, virus assembly and release Structure
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Source
Virus family, there is a virus has a special status, which is tobacco mosaic virus. Whether the discovery of the virus, or later-depth study of the virus, tobacco mosaic virus are the main object of study in virology workers, play a different role. In 1886, the work of the Germans in the Netherlands Mayer (mayer) the mosaic disease of tobacco plants with leaves of water crush, whichever is the health of the tobacco juice was injected into the veins, can cause mosaic disease, proof of the disease is contagious. Through the analysis of leaves and soil, Maier pointed out that tobacco mosaic disease is caused by bacteria. 1892, Russia's Ivanov Sharansky (ivanovski) repeated the experiment Maier, Maier saw confirmed the phenomenon, and further found that the sap of diseased leaves of tobacco plants, through the bacterial filter, also can lead to a healthy mosaic disease of tobacco plants occur. This phenomenon can at least shows that treatment is not a bacterial pathogen, but Ivanov Kaczynski is due to be interpreted as caused by toxins produced by bacteria. Pathogenic bacteria living in the Pasteur said that the heyday era, Ivanov Chomsky further thought not to miss a chance to make important discoveries. The magic of the virus "was born" again! Almost the same time, the German bacteriologist Le Fule (loeffler) and the Faeroe facilities (frosh) found that the pathogen causing bovine foot and mouth disease can also filter by bacteria, which again permits 明伊万诺夫 Chomsky and the great discovery Bergerac Link . "Virus" comes from the Latin word, originally referred to an animal source of the toxin. Virus can proliferation, genetic and evolution, which has the basic characteristics of life, but so far there is no accepted definition of it. Characters used to identify the virus first, such as individual small, generally in the optical microscope can not see, can not pass through the filter bacteria, could not grow in artificial media, such as pathogenic, are still of practical significance. But essentially the distinction between viruses and other biological characteristics are: ① a nucleic acid that contains a single (dna or rna) genomes and protein shell, there is no cell structure; ② in infected cells at the same time or shortly release its nucleic acid, and then DNA replication way to the proliferation of, rather than the proliferation of two way split; ③ strict intracellular parasites. Viruses lack independent metabolism, only in living host cells, using cell biological synthesis machinery to replicate its DNA and synthesis of proteins encoded by nucleic acids, and finally assembled into a complete, have infectious virus units, virus particles. Virus particle is a virus from cell to cell or from host to host the main form of communication. The structure and composition because the virus is simple and easy to train some of the virus and quantitative, so 40 years from the 20th century, the virus has always been an important material for the study of molecular biology. In practice, the fight against the virus of human, plant and animal diseases have made important contributions. Such as vaccine development, the use of insect viruses as pesticides. 1982 data are complete and the virus can be classified into 7 large: (ds) ds dna, enveloped; (ds) ds dna, no capsule; (single chain) ss dna, no capsule; (double chain) ds rna, enveloped; (ds) ds rna, no capsule; (single chain) ss rna, enveloped; (single chain) ss rna, without capsule.
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Features
Duality of the nature of the virus; First, the dual nature of the virus life forms 1, there is the duality of the virus life activity of the virus is very special, absolutely dependent on the cells. The existence of two forms: First, the extracellular form, one form of the cell. When present in the extracellular environment is not significant replication activity, but remains active infection, a virus or viral particles in the form body. Into the cell is the disintegration of the release of nucleic acid molecules (dna or rna), by the conditions of the intracellular environment in a unique system of life activity of reproduction, is the form of nucleic acid molecules. 2, the virus crystalline and amorphous nature of the virus can be purified as a crystal. We know that crystal is a chemical concept, the existence of many a form of inorganic compounds, we can consider some of the virus in the chemical and life activities of crystalline type of two forms. 3, particle form and the form of genetic forms of virus particles present in the cell to outside, this time, only with infection. Once the disintegration of infected cells and release of virus nucleic acid genome before replication and proliferation, and produce new progeny virus. Some of the viral genome integrated into the cell genome, with the breeding and proliferation of cells, then the form of the virus that is the proliferation of genes, rather than the proliferation of granular form, which is a way of virus latent infection. Second, the duality of structure and function of virus 1, the standard virus and defective proliferation of the virus in the virus, because its genome for some micro-environmental factors or transcription errors and mutations, resulting in incomplete assembly of virus particles are produced, called the virus, defects The original parental virus virus, known as the standard virus and defective interfering viral particles has the role of the standard breed disease. 2, false and true HIV virus, there are two viruses from a cell infection, the proliferation process, a virus can put their own case, this is the real virus, the virus should have a "face"; If a virus, the virus nucleic acid to be encoded by another shell, then called a false virus, the original nature of a virus at this time, by another masked by the nature of the virus. 3, pure virus hybrid virus and mixed infection of both viruses, in addition to false-type virus, there may be a virus nucleic acid recombination event that the virus particles among the two viruses may contain genetic material, this may be called hybrid virus, discounted virology a fairly common phenomenon. Third, the dual nature of viral pathology 1, and non-pathogenic virus on the pathogenicity of pathogenic and non pathogenic problems is relatively the same host cell, and at the molecular level, cell level and body level, may have different meanings. Cell disease at the cellular level of effect, but the level in the body may not show clinical symptoms, this may be called subclinical infection or were infected. 2, the viral infection caused by acute and chronic viral infections are acute clinical symptoms, slow the points, and some acute viral infection generally show little expression of chronic infection; some are both acute process, but also chronic process. The concept of the virus can be present are: the virus is no metabolic activity of infection, while not necessarily pathogenic silver, less than their cells, but larger than most of the molecules, without exception, they are living cells in the breeding They contain a protein or a lipoprotein shell and a nucleic acid, DNA or RNA, or nucleic acid and contains only within the protein, or only protein and no nucleic acid, which seems too complicated, as large molecules as biological organisms and their reproduction in a manner different styles. lwoff in the "concept of the virus," a paper emphasizes the special nature of the virus, pointed out that "should the virus is a virus, because they are viral."
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Categories
病毒 分类
病毒 分类
病毒 分类
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病毒 分类
Viruses are widely distributed in nature, can be infected with bacteria, fungi, plants, animals and people, often cause host disease. However, in many cases, the virus can co-exist with the host without causing apparent disease.
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History
病毒 历史
Before the discovery of the virus, people have already begun to use the virus unknowingly to serve mankind. After China in the 16th century to smallpox patients with abscess in the slurry to the healthy people that make them get vaccinated immunity. About the same time, the Dutch tulip growers use grafting to virus infection breaking out the beautiful color flowers; 1796 e. Vaccinia vaccine is satisfied that the invention of piano; 1885 l. Louis Pasteur's first rabies vaccine. 1892 Д. И. Ivanov Sharansky found suffering from tobacco mosaic virus tobacco juice through the filter retention of bacteria, still retain their infectivity; 1898 m. w. Baiyelinke once again discovered this fact and that the disease is a type of bacteria caused by different pathogens. This is the beginning of understanding of the virus. After many human beings have been found, plant and animal diseases are caused by a virus. F. 1898 a. j. Le Fule and p. Luo Shi Fu discovered foot and mouth disease virus of cattle; 1915 f. w. Sweetwater and 1917 f. Ai Leier bacteria and viruses that were found in the phage. From the 30 years since the virus began to explore the physical and chemical properties, m. Schlesinger purification of the phage and that it is composed of proteins and dna; 1935 w. m. Stanley won the crystallization of tobacco mosaic virus; the first time in 1936 under an electron microscope to see the virus is a rod-shaped particles. Many viruses have since been purified, their morphology and chemical composition were studied, provided the basis for virus classification. In practice, the research on the prevention and treatment of human viral, viral diseases of plants and animals have made important contributions. The development of vaccines for the control of human diseases (such as smallpox, yellow fever, polio, measles, etc.) and livestock diseases (such as rinderpest, swine fever, Newcastle disease, etc.) to provide effective measures; the comprehensive prevention and disease the use of breeding and other measures to effectively control the degenerative diseases of potato, wheat soil-borne mosaic virus, cabbage, turnip mosaic virus and other crop diseases; the use of insect viruses as pesticides, but also vigorously and has entered the practical stage .
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Training and testing
Virus and virus is often the development of research culture and detection methods are closely related to the progress, especially in the vertebrate virus, mouse and chicken embryo inoculation, tissue culture, centrifugation, gel electrophoresis, electron microscopy and immunoassay techniques, the development of virology have a profound effect. So far the training and detection of plant viruses are mostly conducted in the whole plant. Juice from the crushed leaf infected by the virus were prepared, often necrotic lesions were detected. Emery mixed with a finger dipped in the diluted virus in plant leaves Villa light friction, a single after a certain time after separation or retirement of green round necrotic spots, known as the dry spots. In addition to using quantitative detection of the pathogenicity of the virus the virus, but can also be applied physical methods, such as counted under the electron microscope the virus particles, or purified virus by UV spectrophotometer the amount of protein and nucleic acids, these methods are the measured data, including the infection and non-infectious virus particles. Application of electron microscopy, virus particles can not only see the size, shape, also can identify the surface of the protein subunit and Ultrastructure of the internal shell. Size and shape Changes in the size of different viruses from 20 to 450 nanometers. Pox virus family is the largest in size (170 ~ 260) × (300 ~ 450) nm, the smallest for the double-virus family, 18 to 20 nm in diameter. Form of the virus is also diverse: spherical (including the icosahedron), such as polio virus and enveloped viruses such as herpes; rods (including bars), such as tobacco mosaic virus; filaments, such as sugar beet yellow virus; slug, such as vesicular stomatitis virus; complex geometries, such as tadpole-like t even phages. Some of the virus in the cell was arranged in the natural crystal.
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Chemical composition and function
病毒 化学组成及功能
病毒 化学组成及功能
DNA with genetic code of the viral genome. Virus by nucleic acid contained can be divided into different types of viruses and rna dna virus. Animal virus or with dna, or containing rna; plant virus except for a few group, mostly rna virus; phage exception of a few families are mostly outside the dna virus. dna or rna can be linear or cyclic, can be a single-stranded or double stranded. rna can be divided into segments or no segment, was divided into single-stranded positive-strand rna and negative chain. In the sub-segment rna plant viruses, it is common polyad genome, in which the same number of rna viruses into the capsid, respectively, in the segment, the formation of particles of different sizes, some particle-packing said the two dyad Genome such as cowpea mosaic virus; some kinds of particles in 3-packing said third gene group, such as cucumber mosaic virus and brome mosaic virus. Through genetic and biochemical methods, have identified some of the virus genome. Of phage ms2 and ΦΧ174. Cauliflower mosaic virus, sv40 and hepatitis B virus nucleic acid sequences, have been identified. ① The main components of the virus proteins, the capsid protein can be divided according to their function, membrane protein, sugar, protein and enzyme within Class 4. ② lipid present in the capsule, the capsule is mature virus from the cell membrane or nuclear membrane budding to obtain, so the virus lipid usually have the characteristics of the host cell lipids. Destruction of organic solvents or detergent lipid envelope, the virus particle cracking can. ③ sugar pentose in addition to DNA, the viral envelope also contains the protein or lipid binding polysaccharide. Tobacco mosaic virus, influenza virus, and Bacillus subtilis phage electron micrograph and structure diagram (see Plant virus, the virus family Orthomyxoviridae viruses and bacteria). Copy Viral replication refers to the invasion of host cells into virus particles induced release of progeny virus particles end the whole process, including adsorption, entry and uncoating, the virus early gene expression, DNA replication, late gene expression, assembly and release steps. Details of each step vary due to the virus. Adsorption and entry t4 phage tail first with its combination of silk and the E. coli surface receptor, followed by tail sheath contraction, Bare shaft penetrates the outer wall of bacteria, dna stored in the head of bacteria injected into the body. Is also the first animal virus with cell receptors, or after phagocytosis by the entry, or the viral envelope fusion with the cell membrane into the shell. Plant viruses are penetrated through wounds or through direct injection of vector insects. In general, viruses are subject to shelling, that is off the release of nucleic acid outside the protein can be copied to the next step. Gene expression On its nucleic acid genetic information transcribed into messenger RNA (mrna), and then translated into protein. DNA replication in general, said the previous early gene expression, produced by early protein, some enzymes required for DNA replication, and some can inhibit the synthesis of nucleic acids and proteins; in DNA replication, said since the beginning of late gene expression, the resulting Late toxic protein particles constitute the major structural protein. Both early and late proteins, including some from the regulatory role of viral replication proteins. Transcription In recent years, found that some viruses (such as adenoviruses and sv40) of the gene is not continuous, there are exons and introns of the points, splicing after transcription, the introns exons cut off and connected to only There mrna features. Most of the virus mrna need to pass through other processing, such as in the 5 'end with "cap" structure and in the 3' end with poly-adenine nucleotides. Enzyme required for viral gene transcription is not the same source, such as small dna virus family, milk and more foam virus depends on the requirements of the Section of rna dna polymerase, the original host of enzymes are used; and slug virus family, Orthomyxoviridae Branch, in the paramyxovirus family and reovirus subjects required depends on the rna rna polymerase, and anti-virus family recorded the required reverse transcriptase, the virus particles are owned. Translation Mrna translation of different viruses is different. The translation is generally believed that the phage polycistronic, as qβ the rna has 3 cistron (encoding a single peptide chain of functional units of genes), can be independently along a mrna translation of the 3 peptides. Translation of animal virus is a single cistron, that is transcribed by a different genome mrna, each mrna translated into a polypeptide. Segmental genome of viruses such as influenza virus and reovirus, each one constitutes a segment rna cistron, polyad genomes of plant viruses as well. Mrna polio virus was first translated into a giant molecular weight peptides of 20 million, and then the cleavage of a capsid protein and enzymes. Some viruses, such as ΦΧ174, qβ phage and sv40 and so on, there is gene duplication, that is, different phase by reading from the same nucleotide sequence can express more than one protein. This is the economical use of its limited viral genetic information for 1 kind of way. DNA replication dna virus in accordance with the classical Watson - Crick base pairing for dna replication. Frothy milk ring dna virus by "rolling circle" model for replication, the need for endonuclease and ligase involved. Rna virus replication by the semiconservative manner, that the virus rna (vrna) as a template, while transcription of several complementary strand (crna), crna transcription is completed and shed, and then transcribed in the manner of new vrna. Therefore, infected cells can be found in some double-stranded structure with a number of different lengths but dragged his single-stranded "tail" (is the synthesis of complementary strand) of the "replication intermediates." Enzyme required for viral DNA replication origin are different. sv40dna synthetic enzymes are required from the host. The qβ rna phage with small rna virus family and plant viruses containing ssrna a required subunit of rna polymerase, possibly encoded by a virus, while other subunits from the host. Herpes virus dna replication enzymes required, in part, encoded by the virus, such as dna polymerase and thymidine kinase, ribonucleotide reductase may also. Pox-like virus strongest independence, even in enucleated cells for dna replication, its genome at least 75 proteins encoded, including dna polymerase, thymidine kinase, DNA enzymes and polynucleotide ligase. Assembly and release Viral RNA replication and structural proteins, respectively, and then assembled into a complete virus particle. The simplest assembly method (such as tobacco mosaic virus) is a nucleic acid and capsid protein of mutual recognition, according to the capsid subunit rna gathered together around a certain way, without the aid of enzymes, and without energy regeneration system. Many icosahedral virus particles first gathering of its capsid, then _insert_ the nucleic acid. Enveloped virus formation in cells after nuclear transfer to the nucleus of virus-modified membrane or the plasma membrane below the way to the release of budding virus particles. t4 phage were then asked to assemble the head, tail and tail, and finally assembled into a complete virus particles, lysis of bacteria and the release of some of the steps needed enzyme. Cell type and level of host response to infection Found that phage infection early cleavage and lysogeny of the points. The E. coli λ phage, for example, through the cracking of the replication cycle of infection in a large number of progeny virus particles generated after the cleavage of the bacteria; and lysogenic infection, the phage dna cyclization and integrated into the E. coli dna specific bit point, with the split and passed to offspring bacteria germs, bacteria will not be cracking not produce progeny virus particles. Nutritional conditions, UV or chemical drugs can make the soluble source of the infection into lytic. Dna animal viruses such as sv40, adenovirus, herpes virus infection of sensitive cells equals (called to allow cells), the formation of lytic infection, while less-sensitive cells in the infection (called does not allow cells), the transformation of the form infection. Lysogenic conversion of the infection and infected with similar virus dna or integrated into the cell chromosome fragments, and passed with cell division and daughter cells, the expression of some of its genes (usually early genes), but does not produce progeny virus particles , cells do not die but was transformed into similar tumor cells can be passaged indefinitely. On the other hand, rna tumor virus (such as chicken tumor virus) must first dsdna rna reverse transcribed and integrated into the cell chromosome, can be copied, so the approach is unique in the infection, both the conversion of the infection, but also produce a large number of virus particles. Host cell response to viral infection has 4 types: no response, cell death, cell proliferation and cell death after the transformation. For example, paramyxovirus sv5 produced in cell culture without causing a large number of significant response to the virus. Most sensitive cells infected, due to inhibition of nucleic acid and protein synthesis and cause cell death. Pox virus infection, first stimulate cell division and death many times, causing chicken pox blister lesions. viral dna and rna tumor virus is caused by cell transformation. Some animal viruses in the infected host cells, the nucleus or cytoplasm in the formation of inclusions of special staining characteristics, called inclusions, such as the pox virus inclusion bodies within the cytoplasm and nuclei of herpes simplex virus inclusion bodies. Some of these inclusion bodies by the immature or mature virus particles form, some reaction products of host cells, some mixture of both. Some insect virus, the virus particles embedded in a protein matrix, the formation of inclusion bodies such as the nuclear polyhedrosis virus. Vertebrate cells after infection another reaction is to produce interferon. Interferon is a protein encoded by animal cells, the gene is inactive usually in double-stranded rna virus infection or after induction of activation. A broad-spectrum antiviral activity of interferon, but not directly on the virus, and its mechanism is combined with the cell membrane, the activation of 3 enzymes with antiviral activity, blocking the virus mrna translation. Interferon in the prevention of spread of the virus and the disease has a role in recovery, and there may be an antiviral drug. Body type and level of host response to infection Higher animals can produce specific immune response viral infection. Immune response is divided into two types of humoral and cellular immunity, humoral immunity performance of the grounds of b cell antibodies, which include the ability to specifically inactivate virus neutralizing antibodies. Neutralizing antibody to prevent reinfection plays a leading role. The main performance of cellular immunity is to identify and react with viral antigen t-lymphocytes, in clearing the virus and virus infected cells play a leading role. Often an allergic reaction to the virus in plant cells, cells rapidly died, the formation of dry spots, while viral replication was limited. Another response is to produce a very anti-viral factors such as interferon, can protect uninfected cells.
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Hazards
Tumorigenic effects Origin Origin of the virus had been speculated; One view is that the virus may be similar to the most primitive life; the other that the virus may come from bacterial degradation, due to the high development of parasites gradually lose the ability to live independently , for example, by saprophytic fungi parasite → → → intracellular parasite Rickettsia Mycoplasma → → → Chlamydia large virus → small virus; there is a think that the virus may be a product of the host cell. These have some basis for speculation, has not been determined. Therefore, evolution of the virus in the status undetermined. However, regardless of their original origins, once the disease is produced, as with other organisms, through mutation and natural _select_ion and evolution. Categories The work of naming the virus is now classified by the International Committee on Taxonomy of Viruses, was published in 1982, 1971,1976,1979 and 4 report. More complete data in 1982, but the virus can be classified into seven large, clustering is based on the type of genomic nucleic acid (dna or rna), type (ds or ss), and whether the capsule. 7 large group of 59 subjects in the group: dsdna, enveloped 4 families dsdna, no capsule, 8 families, a group of ssdna, no capsule, 3 families, 1 dsrna, enveloped 1 family dsrna, no capsule 1 family, 4 possible subjects ssrna, enveloped 8 families, a group of ssrna, no capsule, 4 families, 22 groups, one may _set_ If classified by the host, was: 10 families of bacteria and viruses Section 3 may be fungal virus 24 groups of plant viruses, one may _set_ Invertebrate virus 2 Division, 1 9 families vertebrate virus Invertebrates, vertebrates, there are 6 families of viruses, pox virus family that is iridescent virus family, the small dna virus family, Phi membrane virus family, Bunyaviridae virus family and small-rna, and a possible subjects, ie segment double-stranded rna virus. Invertebrates, vertebrates and plants, a total of 2 families of viruses that reovirus-like virus family branches and shells. Classification is still in the early stages of the virus, but also the rapid development and evolution of the future. More complete information on current animal viruses and bacteriophages have been established as a Section, Family Name using Latin; and established plant virus only group, the group name and more use of reduced spelling, about a subject typical of the common name of the virus, such as tobacco mo-saic virus reduction spelled tobamo-virus. Division is divided subfamily and genus, its is the common name of each virus, yet minutes.
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Role
The benefits of biological viruses 1, the phage can be used as cure for prevention and treatment of certain diseases, such as burn patients in the affected area apply Pseudomonas aeruginosa phage dilution 2, in cell engineering, cell fusion of certain viruses can be used as the assistant financial agent, such as Sendai virus 3, in genetic engineering, the virus can be used as the carrier of the gene, so that was spliced in the target cell chromosome 4, the bacteria in medium supplemented with specific virus can be purify 5, the virus can be used as precision-guided drug carrier 6, the virus can be used as effects of pesticides Vaccine virus to humans is good - to promote the evolution of mankind, many human genes are derived from the virus. A virus is a non-cell life forms, it consists of a long chain of nucleic acid and protein shell form, the virus did not have a metabolic body which has no enzyme system. Therefore, the virus left the host cell, it becomes a no life activities, nor an independent self-reproduction of chemical substances. Once inside the host cell, it can use the cells in the matter and energy as well as replication, transcription and translation of the ability of the nucleic acid in accordance with its own genetic information contained in the same generation and its new generation of viruses. Viral genes with other organisms, genes, mutation and recombination can occur, and therefore can be evolved. Because the virus is no independent metabolism of body, not an independent breed, it is considered an incomplete form of life. Also found the virus in recent years than the simple-like virus, which is a small rna molecules, no protein shell, but it can cause disease in animals. These life forms are not complete without the presence of that life and there is no unbridgeable gap between the life.
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Computer Virus
计算机病毒
计算机病毒
Computer viruses are not familiar with what we call the biological virus, computer virus is a program, a section of executable code. However, the computer virus as biological virus, has a unique ability to replicate. With the biological virus computer viruses can spread quickly and are often difficult to eradicate. They can attach themselves in all types of documents. When the files are copied or from one user to another user, they spread with the accompanying documents. In addition to replication, the computer viruses and biological viruses as well as some other common characteristics: a program infected with the virus vector can transmit the virus, as infectious diseases. When you see the performance of viral vectors appears only on the text and image, they may also have destroyed the file, and then reformat your hard drive, remove the drive or cause other types of disasters. If the virus does not parasitic infection in a single program, it occupies storage space through the trouble to you, and to reduce the full performance of your computer. And biological similarities in the dissemination of the virus is "computer virus" origin of the name. The definition of computer virus Can be presented from different angles the definition of computer viruses. A definition is: The disk, tape and network as a vector-borne spread, can "infect" other programs in the program. The other is: the ability to replicate and realize their own existence with the carrier with a certain latent, infectious and destructive process. There is defined as: a man-made program that potential through different means or parasitic in the storage media (such as disk, memory) or a program in. When certain conditions or when the time comes, it will self replicate and spread, so that computer resources are subject to different procedures for the destruction and so on. These claims, in a sense borrowed the concept of biological viruses, computer viruses is similar to biological viruses can play an intrusion into computer systems and networks, working against "pathogens." It can sabotage of computer systems, while self-replication, is contagious. Therefore, the computer virus is hidden in some way through a computer storage medium (or program), when a particular condition is activated when the computer resources that have damaging effects on a _set_ of procedures or instruction _set_. The preparation of computer virus is _insert_ed in a computer program or the destruction of computer functions or destroy data, and can affect self-replicating computer using a _set_ of computer instructions or code. Able to describe the fundamental properties of computer virus is self-replicating and destructive Computer virus definitions: One. The definition of computer virus computer virus (computer virus) in the "PRC Regulations on Protection of Computer Information System Security," was clearly defined, the virus "refers to the preparation of computer programs or computer functions to _insert_ the damage or destruction of data, use of computer and a group of self-replicating computer instructions or code. " II. Computer virus computer viruses are man-made features of special procedures, self-replicating, highly infectious, and certain latent, the specific trigger and very destructive. III. Virus in the information needs of the inevitability of computer access, copying, transmission, the virus can be used as a form of information, along with reproduction, infection, damage, and when to obtain control of the virus, they will take the initiative to find the infection target to its own widespread. IV. Computer viruses often take advantage of the long-term virus computer operating system vulnerabilities to spread, improve system security is an important aspect of anti-virus, but the perfect system does not exist, too much emphasis on improving the security of the system will Most of the time for virus checking system, the system lost the availability, practicality and ease of use, on the other hand, the requirements of confidentiality of information disclosure and let people catch the virus can not choose between. Virus and anti-virus technology as a long confrontation, the two technologies will be the development of computer technology with the long-term, development. Five. The production of computer viruses from the virus is not unexpected or accidental causes. A sudden power outage and accidental errors in the computer's disk and memory have some garbled and random order, but the code is disorder and chaos, the virus is a more perfect, delicate strict code, in accordance with the organized in a strict order, with the host system network environment to adapt to and meet up, the virus is not formed by accident, and the need for a certain length, the length of the basic probability of speaking is not possible from the random code generated by. Special procedures man-made virus is now circulating virus is written by the man deliberately, most virus can find information and the origin of information, through a lot of data analysis statistics show that the virus of the situation and main objectives are: some talented programmers to express themselves and demonstrate their ability, in the dissatisfaction of the boss, to curiosity, to revenge, to congratulate and courtship, in order to get control of the password, in order to not get the reward reserved for software traps. Of course there are because of political, military, religious, ethnic. Patents and other needs and specially prepared, including a number of research institutions and hackers virus test virus. VI. Computer virus classification based on years of research on computer viruses, according to a scientific, systematic and rigorous methods, computer viruses can be classified as follows: In accordance with the method of computer viruses classification of property, computer viruses can be classified according to the following attributes: Presence of the media in accordance with computer viruses are classified according to the media presence of the virus, the virus can be divided into the network viruses, file viruses, boot virus. Network virus infection through the computer network communication network executable file, the virus infected computer files (such as: com, exe, doc, etc.), boot virus infected the boot sector (boot) and hard disk boot sector ( mbr), there are three cases of mixed type, such as: multi-type virus (the file and boot type) infected files and boot sector of two goals, this virus usually have complex algorithms, they use unconventional methods into the system, using both encryption and deformation algorithms. In accordance with the method of transmission of computer viruses are classified according to the method of transmission of the virus can be divided into resident and non-resident virus virus, presence of virus infection computer, the part of its memory-resident in memory (ram) in This part of the program and hook system calls into the operating system to go, he is active until the shutdown or restart. Non-resident viruses are not infectious when given the opportunity to activate the computer's memory, some virus left in memory small part, but does not pass through this part of the infection, this virus has also been classified as non-resident viruses. In accordance with the capacity to destroy computer viruses are classified according to undermine the ability of the virus can be divided into the following categories: when the reduction of sound transmission-type addition to the available disk space, no other effect on the system. No risk types of this virus is only to reduce the memory, display images, sounds and similar sound. Risk types of this virus in the computer system operating in a serious error. Remove this virus very dangerous type of program, destroy data, clear the system memory area and operating systems important information. These viruses cause harm to the system, the algorithm is not dangerous in itself a call, but when they are infected will cause unpredictable and catastrophic damage. Caused by a virus program generates other errors will destroy files and sectors, these viruses have caused damage according to their ability to divide. Some are harmless virus also may have a new version of dos, windows and other damage to the operating system. For example: In the early viruses, there is a "denzuk" virus in the 360k very good job on the disk will not cause any damage, but in high-density floppy disk was able to cause a lot of data loss. Algorithm by computer virus-specific classification algorithm based on the virus-specific virus can be divided into: With this type of virus does not change the virus file itself, they are based on algorithms generated exe file with the body, with the same name and different extensions Name (com), for example: xcopy.exe accompanying body is xcopy.com. Viruses have written to the file does not change com exe file, when the dos load files, along with the primacy of being executed, then loaded the body with the implementation of the original exe file. "Worm" virus spread through computer networks, without changing the documents and data information, the use of the network from a machine's memory, the memory spread to other machines, computing network address, the virus itself sent over the network. Sometimes they exist in the system, generally do not take up other resources in addition to the memory. In addition to the parasitic virus with and the "worm" type, and other viruses may be referred to as parasitic viruses, they are attached to the boot sector or file to spread through the function of the system, according to their algorithm can be divided into: Practice type HIV virus itself contains errors, can not be very good spread, for example, the virus in the commissioning phase. Stealth virus that they generally do not directly modify the dos interrupt and sector data, but through technology and equipment within the modified file buffers dos, easy to see resources, the use of more advanced technology. Data area using dos to work free. Variant virus (also known as the specter of the virus) this type of virus uses a complex algorithm, so that their every communication has a different content and length. They are generally a mixed approach is independent of the instruction decoding algorithm and the virus had been changes in body composition.
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Overview
Virus particles is small, the measured in nanometers, simple structure, parasitic strictly to copy for reproduction of a class of non-cell organisms. Viruses are smaller than bacteria, there is no cell structure, only the proliferation of living cells of microorganisms. Composed of proteins and nucleic acids. Most use the electron microscope can be observed. Simple to understand Virus, is a class of non-cellular structure, with genetic, reproduction and other vital signs of microorganisms. As with all biological virus, with genetic variation, evolution, is a very small size, the structure is extremely simple life forms, a high degree of parasitic virus, entirely dependent on host cell energy and metabolism system, access to the necessary life activities matter and energy, leaving the host cell, it's just a big chemical molecules, and stop activities, can be made of protein crystallization, as a non-being, it will face host cells by adsorption, entry, replication, assembly, release of progeny virus shows the typical characteristics of living organisms, so the virus is between biological and non-living a primitive life form. Virus Category: The first category: the virus protein, DNA Classification from the genetic material: DNA virus, RNA virus, viral proteins (such as; PrP) The second category: General virus, virus From the host type classification: phage (bacterial virus), plant viruses (eg tobacco mosaic virus), animal viruses (such as avian influenza virus, smallpox virus, HIV, etc.) Form of the virus (1) spherical virus; (2) baculovirus; (3) brick-shaped virus; (4) coronavirus; (5) enveloped spherical virus; (6) with the globular head of the virus; (7) letters insect viruses that contain the body. Virus particles in the symmetric system: Symmetric structure of virus particles are only two, namely helical symmetry (on behalf of the tobacco mosaic virus) and icosahedral symmetry (such as axial symmetry, on behalf of adenovirus). Some more complex structure of the virus, essentially the result of a combination of two symmetrical, so called compound symmetry (on behalf of T even phage) The size of the virus Most of the virus in diameter, 100nm (20 ~ 200nm), the larger diameter of 300-450 nm virus (nm), the smaller the diameter of only 18-22 nm virus Composition of the virus Virus is mainly formed by the nucleic acid and protein coat. Because the virus is a type of non-cell organisms, it is not a single instance of the virus called "single cell", thus creating a body of virus particles or virus (virion). Virus particles are sometimes also called viral particles or virus particles (virus particle), specifically refers to the structural integrity of mature and have a single infectious virus. nucleic acids at its center, known as the core (core) or genome (genome), the protein core surrounded around the formation of a capsid (capsid). capsid is The main support structure of virus particles and antigen composition, such a protective effect of nucleic acids. capsid is composed of many identifiable in the electron microscope, the morphological subunit (subunit) - capsid particles (capsomere) posed. Collectively known as the core of the core and capsid shell (nucleocapsid). Some of the more complex viruses, (usually for animal viruses such as influenza virus), was also a layer outside the core shell protein or glycoprotein with lipid bilayer membrane covered, this layer membrane called the capsule (envelope). The lipid envelope from the host cell membrane. Still having some envelope spike (spike) and other appurtenances. Availability and nature of the envelope of the virus and the invasion of host specificity and other functions. Type 1 virus in insect polyhedrosis virus, and its shell is coated protein crystals to form a polygonal inclusion bodies. Viral replication process is called replication cycle. It can be divided into five consecutive stages: adsorption, invasion, proliferation, maturation (assembly), cleavage (release). Emergence of the virus hypothesis: 1. Protein, nucleic acid loss, said: Large biological (meaning here is a large cell structure of biological creatures, different from the non-cellular structure of biological viruses) fall and rupture the cells, resulting in the free protein and DNA, RNA appears, in some cases, these proteins as chemical forms an internal structure to accommodate small molecules, many of these proteins, which wrapped DNA or RNA, or protein and separate individual DNA, RNA free, free of these scattered elements, there are some individual and large biological cell membrane affinity, large living cells to enter the cell through phagocytosis, the DNA, RNA can be expressed, and then evolved is now a mature virus. 2. The origin of life, said: Virus is the most primitive form of life there early before the virus in the absence of cells there, when the virus is also limited to proteins and nucleic acids, did not show the parasitic characteristics of the virus, when the advent of the cell body of biological, individual proteins and nucleic acids such or their parasitoids emerged in the composite surface, follow the process above.
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History
病毒 历史
On the disease caused by the virus as early as two to three centuries BC, India and China have a record on the ceiling. It was not until the 19th century, before the virus began to be discovered and identified. In 1884, the French microbiologist Charles still Bailang (Charles Chamberland) invented a filtration filter bacteria can not (Chamberland's candle-shaped filter, the filter pore diameter less than the size of bacteria), he used this can filter the bacteria present in the liquid removed. In 1892, the Russian biologist Ivanov Chomsky (Dmitry Ivanovsky) in the study found that tobacco mosaic virus, the tobacco mosaic virus infected leaves extract filtered with a candle-shaped filter is still able to infect other tobacco . He proposed that infectious agents may be a toxin secreted by bacteria, but he did not go in-depth study. At that time, people thought that all infectious substances can be filtered to remove and can grow in the medium, which is the germ theory of disease (germ theory) part of it. In 1899, the Dutch microbiologist 马丁乌斯贝 Jie Linke (Martinus Beijerinck) Ivanovsky repeated experiments, and believe that this is a new infectious material. He also observed that this pathogen replicate only in dividing cells, because his experiments did not show such a pathogenic form of particles, so he called contagium vivum fluidum (soluble viable cells) and further named virus (HIV). Bergerac Link that virus is present in liquid form (but this view was later overturned temperature 德尔梅雷迪 Sisitanli, he proved the virus was granulated). Also in 1899, Friedrich Loeffler and Paul Frosch found in animals suffering from foot and mouth disease in lymph through the filter containing infectious substances, because after a high degree of dilution, excluding the possibility that it is toxic; they can infer that infectious substances self-replication. The early 20th century, the British bacteriologist Frederick Twort discovered a virus that can infect bacteria, and called phage. Followed by French Canadian microbiologist Félix d'Herelle describes the characteristics of phage: to add the agar covered with bacteria on solid medium, there will be some time after the death of the bacteria in plaque left behind. High concentrations of virus suspension medium, the bacteria will all die, but by precise dilution, can produce recognizable plaque. By calculating the number of plaques, and then multiplied by the dilution factor can be drawn on the number of viruses in solution. Their work opened the curtain of modern virology. In the 19th century, the characteristics of the virus is considered to be infectious, and can be filtered and the need for a living host, which means the virus can only grow in animals or plants. In 1906, Harrison invented the lymph tissue growth in the method; Then in 1913, E. Steinhardt, C. Israeli and RA Lambert using this method successfully in the guinea pig corneal tissue cultured bovine vaccinia virus, a breakthrough the virus needs to limit the growth of the body. 1928, HB Maitland and MC Maitland has further breakthroughs, they use chopped chicken kidney suspension were cultured on bovine vaccinia virus. Their method can be widely used in the 1950s large-scale polio vaccine production. American scientist Wendell Stanley in 1931, the German engineer Ernst and Mark Andrews card invented the electron microscope Noel Trask, making the researchers obtained the first pictures of the virus shape. In 1935, U.S. biochemist and virologist temperature 德尔梅雷迪 Sisitanli found that most of the tobacco mosaic virus is composed of protein, and get the virus crystal. He then successfully isolated the virus and the RNA for the protein part of the section. Wendell Stanley because of his discovery won the Nobel Prize in Chemistry in 1946. Tobacco mosaic virus is the first crystallization of the virus, which can be X-ray crystallography to get the details of its structure. The first X-ray diffraction photograph the virus by Bernal and Fankuchen taken in 1941 years. In 1955, the virus through the analysis of diffraction photograph, Rosalind Franklin reveals the overall structure of the virus. In the same year, Heinz Fraenkel-Conrat and Robley Williams found that the separation and purification of tobacco mosaic virus RNA and capsid protein mixed together, can be re-assembled into infectious virus, which also reveals the likely mechanism for this is simple virus host cells in their assembly process.
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Chemical composition and function
DNA with genetic code of the viral genome. Contained the virus by nucleic acid can be divided into different types of DNA viruses and RNA viruses. Containing animal viruses or DNA, or with RNA; plant virus group, mostly except for a few RNA viruses; phage exception of a few families are mostly outside the DNA virus. DNA or RNA can be linear or cyclic, can be a single-stranded or double stranded. RNA can be divided into segments or no segment, was divided into single-stranded RNA positive-strand and negative chain. In the sub-segment RNA plant viruses, it is common polyad genome, in which the same number of virus RNA segments into the capsid, respectively, in the form of particles of different sizes, some particle-packing said the two dyad Genome such as cowpea mosaic virus; some kinds of particles in 3-packing said third gene group, such as cucumber mosaic virus and brome mosaic virus. Through genetic and biochemical methods, have identified some of the virus genome. Phage MS2 and ΦΧ174 on. Cauliflower mosaic virus, SV40, and hepatitis B virus nucleic acid sequences, have been identified. ① The main components of the virus proteins, the capsid protein can be divided according to their function, membrane protein, sugar, protein and enzyme within Class 4. ② lipid present in the capsule, the capsule is mature virus from the cell membrane or nuclear membrane budding to obtain, so the virus lipid usually have the characteristics of the host cell lipids. Destruction of organic solvents or detergent lipid envelope, the virus particle cracking can. ③ sugar pentose in addition to DNA, the viral envelope also contains the protein or lipid binding polysaccharide. Tobacco mosaic virus, influenza virus, and Bacillus subtilis phage electron micrograph and structure diagram (see Plant virus, the virus family Orthomyxoviridae viruses and bacteria). Copy Viral replication refers to the invasion of host cells into virus particles induced release of progeny virus particles end the whole process, including adsorption, entry and uncoating, the virus early gene expression, DNA replication, late gene expression, assembly and release steps. Details of each step vary due to the virus. Adsorption and entry Bacteriophage T4 tail first with its combination of silk and the E. coli surface receptor, followed by tail sheath contraction, Bare shaft penetrates the outer wall of bacteria, the DNA stored in the head of bacteria injected into the body. Is also the first animal virus with cell receptors, or after phagocytosis by the entry, or the viral envelope fusion with the cell membrane into the shell. Plant viruses are penetrated through wounds or through direct injection of vector insects. In general, viruses are subject to shelling, that is off the release of nucleic acid outside the protein can be copied to the next step. Gene expression On its nucleic acid genetic information transcribed into messenger RNA (mRNA), and then translated into protein. DNA replication in general, said the previous early gene expression, produced by early protein, some enzymes required for DNA replication, and some can inhibit the synthesis of nucleic acids and proteins; in DNA replication, said since the beginning of late gene expression, the resulting Late toxic protein particles constitute the major structural protein. Both early and late proteins, including some from the regulatory role of viral replication proteins. Transcription In recent years, found that some viruses (such as adenoviruses and SV40) genes are not continuous, there are exons and introns of the points, splicing after transcription, the introns exons cut off and connected to only with mRNA function. Most of the virus mRNA need to pass through other processing, such as in the 5 'end with "cap" structure and in the 3' end with poly-adenine nucleotides. Enzyme required for viral gene transcription is not the same source, such as small DNA virus family, frothy milk depends on the DNA required for the virus family of RNA polymerase, the original host of enzymes are used; and bomb-like virus family, Orthomyxoviridae Branch, in the paramyxovirus family and the requirements of the Section reovirus RNA-dependent RNA polymerase of, and need anti-virus family recorded reverse transcriptase, the virus particles are owned. Translation Different virus mRNA translation is different. The translation is generally believed that the phage polycistronic, such as Qβ RNA on the 3 cistron (encoding a single peptide chain of functional units of genes), along an mRNA can be translated independently 3 peptides. Translation of animal virus is a single cistron, that is transcribed into the genome by a different mRNA, each mRNA translated into a polypeptide. Segmental genome of viruses such as influenza virus and reovirus, each one constitutes a section of RNA cistron, polyad genomes of plant viruses as well. Poliovirus mRNA is first translated into a giant molecular weight peptides of 20 million, and then the cleavage of a capsid protein and enzymes. Some viruses, such as ΦΧ174, Qβ phage and SV40, etc., there is gene duplication, that is, different phase by reading from the same nucleotide sequence can express more than one protein. This is the economical use of its limited viral genetic information for 1 kind of way. DNA replication DNA virus according to the classical Watson - Crick base pairing for DNA replication. Frothy milk ring virus DNA by "rolling circle" model for replication, the need for endonuclease and ligase involved. Virus RNA replication by way of semi-reservation, that the virus RNA (vRNA) as template, while transcription of several complementary strand (cRNA), cRNA transcribed completed and shed, and then transcribed in the manner of new vRNA. Therefore, infected cells can be found in some double-stranded structure with a number of different lengths but dragged his single-stranded "tail" (is the synthesis of complementary strand) of the "replication intermediates." Enzyme required for viral DNA replication origin are different. SV40DNA synthetic enzymes are required from the host. With the Qβ phage RNA, small RNA virus family and ssRNA plant viruses containing RNA polymerase a subunit required, may be encoded by a virus, while other subunits from the host. Herpes simplex virus DNA replication enzymes required, in part, encoded by the virus, such as DNA polymerase and thymidine kinase, ribonucleotide reductase may also. Pox-like virus strongest independence, even in enucleated cells, DNA replication, its genome at least 75 proteins encoded, including DNA polymerase, thymidine kinase, DNA enzymes and polynucleotide ligase. Assembly and release Viral RNA replication and structural proteins, respectively, and then assembled into a complete virus particle. The simplest assembly method (such as tobacco mosaic virus) is a nucleic acid and capsid protein of mutual recognition, according to the capsid subunit RNA gathered together around a certain way, without the aid of enzymes, and without energy regeneration system. Many icosahedral virus particles first gathering of its capsid, then _insert_ the nucleic acid. Enveloped virus formation in cells after nuclear transfer to the nucleus of virus-modified membrane or the plasma membrane below the way to the release of budding virus particles. T4 phage were then asked to assemble the head, tail and tail, and finally assembled into a complete virus particles, lysis of bacteria and the release of some of the steps needed enzyme. Cell type and level of host response to infection Found that phage infection early cleavage and lysogeny of the points. The E. coli λ phage, for example, through the cracking of the replication cycle of infection in a large number of progeny virus particles generated after the cleavage of the bacteria; and lysogenic infection, phage DNA cyclization and integrated into the E. coli DNA specific bit point, with the split and passed to offspring bacteria germs, bacteria will not be cracking not produce progeny virus particles. Nutritional conditions, UV or chemical drugs can make the soluble source of the infection into lytic. Animal DNA viruses such as SV40, adenovirus, herpes virus infection of sensitive cells equals (called to allow cells), the formation of lytic infection, while less-sensitive cells in the infection (called does not allow cells), the transformation of the form infection. Lysogenic conversion of the infection and infected with similar viral DNA integrated into the cell or chromosome fragments, and with cell division and passed to daughter cells, the expression of some of its genes (usually early genes), but does not produce progeny virus particles , cells do not die but was transformed into similar tumor cells can be passaged indefinitely. On the other hand, RNA tumor viruses (such as chicken tumor virus) must first reverse transcription of its RNA into dsDNA and integrated into the cell chromosome, can be copied, so the approach is unique in the infection, both the conversion of the infection, but also produce a large number of virus particles. Host cell response to viral infection has 4 types: no response, cell death, cell proliferation and cell death after the transformation. For example, the paramyxovirus SV5 in cell culture produces a lot of the virus without causing significant reactions. Most sensitive cells infected, due to inhibition of nucleic acid and protein synthesis and cause cell death. Pox virus infection, first stimulate cell division and death many times, causing chicken pox blister lesions. DNA viruses and RNA tumor viruses are caused by cell transformation. Some animal viruses in the infected host cells, the nucleus or cytoplasm in the formation of inclusions of special staining characteristics, called inclusions, such as the pox virus inclusion bodies within the cytoplasm and nuclei of herpes simplex virus inclusion bodies. Some of these inclusion bodies by the immature or mature virus particles form, some reaction products of host cells, some mixture of both. Some insect virus, the virus particles embedded in a protein matrix, the formation of inclusion bodies such as the nuclear polyhedrosis virus. Vertebrate cells after infection another reaction is to produce interferon. Interferon is a protein encoded by animal cells, the gene is inactive usually in double-stranded RNA virus infection or after induction of activation. A broad-spectrum antiviral activity of interferon, but not directly on the virus, and its mechanism is combined with the cell membrane, the activation of 3 enzymes with antiviral activity, blocked the translation of viral mRNA. Interferon in the prevention of spread of the virus and the disease has a role in recovery, and there may be an antiviral drug. Body type and level of host response to infection Higher animals can produce specific immune response viral infection. Immune response is divided into two types of humoral and cellular immunity, humoral immunity performance of the grounds of B cells to produce antibodies, which include the ability to specifically inactivate virus neutralizing antibodies. Neutralizing antibody to prevent reinfection plays a leading role. The main performance of cellular immunity is to identify and react with viral antigen T-lymphocytes, in clearing the virus and virus infected cells play a leading role. Often an allergic reaction to the virus in plant cells, cells rapidly died, the formation of dry spots, while viral replication was limited. Another response is to produce a very anti-viral factors such as interferon, can protect uninfected cells. For example: EV71 intestinal virus According to experts, intestinal virus EV71 is a human enterovirus, called EV71, can occur throughout the year, is common in 4 to 9 months, mainly through saliva, herpes fluid, feces contaminated hands, towels, handkerchiefs, tooth cup, toys, utensils, milk with and bedding, underwear and other close contact, often in children hand foot and mouth disease, viral angina, severe pulmonary edema can occur in children, encephalitis, etc., collectively referred to as intestinal virus EV71 infection. The disease mostly occurs in children, especially infants and children under 3 years old and more hair, a few serious condition, a serious cause of death. EV71 intestinal virus infection in children after the on_set_ of fever and more, usually around 38 ℃, fever, while in the mouth, hand, foot, buttocks, skin rash or herpes with oral mucosa. Some patients have a cough and other flu-like early performance. 1 to 2 days after fever rash usually appears on the palms and soles, can also appear in the buttocks. Some children with no fever, only the performance of the hands, feet, buttocks rash or herpes angina, mild. Most children in one week the temperature drops, the rash subsided, the disease recovery. Chinese Center for Disease Control and Prevention experts say that if that child has a fever, a rash and other symptoms as soon as possible to a regular hospital. After sick children to kindergartens and schools should be suspended to prevent transmission to others, to prevent further infection of other diseases. Experts stress that children should use the family soap, disinfectant 84 daily necessities, toys, diapers for disinfection of milk tools, tableware boiling disinfection. Manure and other waste can be used in children with disinfectants or bleach disinfection; to clothing, sun exposure, indoor maintain ventilation. Spring is prone to intestinal virus infection season, to pay attention to environmental health, food sanitation and hygiene. Do not drink unboiled water, not to eat raw food, wash hands before meals and after, maintain good indoor ventilation. Try not to bring infants and young children to crowded places. Breast-feeding mothers should wash bath, changing clothes frequently, clean the nipple before feeding. In nurseries, primary schools and other children's collective life, a place to learn, experts recommend the morning to do physical examination, found to have fever, rash, children, parents take their children to be immediately called to the hospital, while reporting the relevant departments. If there is fever, rash, after the children, to immediately toys, bedding, furniture and other disinfection; while doing canteen, toilets, classrooms, etc. disinfection.
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Unusual natural role
病毒 不同寻常的自然角色
In fact, the virus is not nothing, it is human survival and evolution of the process, playing an unusual role, and vertebrates, where the virus obtained directly from the 100 kinds of genes, and DNA replication of human self enzyme system, may also from the virus.
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Computer Virus
A malicious computer code that can damage the system program, space, steal account passwords. Can lead to severe network, system down. See computer virus
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Novel virus
小说病毒
Title: "virus" Of: Cai Jun ISBN: 9787104015185 Pages: 268 Price: 14.8 Binding: Paperback Published on :2002-04 Publisher: Chinese Theatre Press Description:
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Film virus
电影病毒
Video Name: Virus English name: Virus Genre: Science Fiction Release Date: November 18, 2002 Release Region: United States / United Kingdom Video language: English Movie Length: 106 minutes Cast: Jamie Lee Curtis, William Baldwin Synopsis: Destroy all the viruses (Virus) - [human]. Ocean Tug "Ocean Star" suffered a severe accident in the South Pacific typhoon attacks, face the danger of sinking. A seven-member team driving the boat into the eyes of the typhoon, typhoon eyes they found a 640-foot long, but empty high-tech Russian research vessels. In fact, back before they boarding, the ship nine feet high, with multiple flying wing called the "Goliath" super ships, has been shaped by a group from outer space occupied by the computer to learn their human After all, the full implementation of its ultimate mission: destroy all the virus (Virus) - [human]. So they occupied all the advanced technological equipment, comprehensive transformation of the crew of a ship to kill monsters in an attempt to wipe out humanity on Earth. Because of their destructive power of large, super-lethal, but they need to rely on the survival of extremely powerful ship of power, the seven member group plans to "Ge Li Ya" and lead to the bottom of all aliens in the sudden rain of Feng Kuang Typhoon night, they really can beat the aliens? In full security can survive? More important is whether the Earth be rescued?
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Computer Virus
A malicious computer code that can damage the system program, space, steal account passwords. Can lead to severe network, system down. See computer virus Removal method Use antivirus software security clearance. Virus name is composed of the following six fields: the main type of behavior. Sub-type of behavior. Host file types. The main name. Version. The main name of the variant number # sub name. Subsidiary name of the variant number. The virus length. Between the fields in which to use "." Separated, after the # are the internal information, as elected structure. Sub main type of behavior and behavior type virus Virus may contain more than one primary type of behavior, this type of behavior can harm each level of the main hazards to determine the highest level of the main acts as a type of virus. Similarly, the virus may also contain multiple sub-type of behavior, this type of behavior can harm each level of the main hazards identified as the highest level of virus sub-type of behavior. Hazard level which is where the computer virus damage. Whether the virus has shown the main type of behavior attributes, used to generate the virus name to hide the name of the main acts. It exists with the virus sub-type of correspondence between behavior, as follows: Behavior of the main types of sub-type of behavior Backdoor Hazard Level: 1 Description: Chinese name - "back door", is not allowed without the user knowing the circumstances, in the infected system to run covert system can be infected with remote control, and users can not prohibit the normal way operation. "Back door" is actually a special case of Trojan, the difference between them lies in the "back door" on infected systems can be remotely controlled (such as: document management, process control, etc.). Worm Hazard Class: 2 Description: Chinese name - "worm" refers to the use of loopholes in the system, outgoing mail, shared directory, the software can transfer files (such as: MSN, OICQ, IRC, etc.), removable storage media (such as: U disk, floppy disk), These methods spread their virus. This type of virus sub-type behavior of its type to use for that mode of transmission of the virus. Mail Hazard Level: 1 Note: Communication through e-mail IM Hazard Class: 2 Note: do not clear through a specific carrier or multiple carriers spread their MSN Hazard Class: 3 Note: Communication through MSN QQ Hazard Level: 4 Note: Communication through OICQ ICQ Hazard Level: 5 Note: Communication through ICQ P2P Hazard level: 6 Description: The spread of P2P software IRC Hazard Class: 7 Note: Communication through ICR Note: do not rely on other means of communication to spread the software, such as: the use of loopholes in the system, shared directories, removable storage media. Trojan Hazard Class: 3 Description: Chinese name - "Trojan horse" refers to not allow the user does not know the circumstances, the infected system to run hidden, and users can not prohibit the normal way through the run. The purpose of this virus usually have interests, the interests of its purposes is the sub-behavior of the virus. Spy Hazard Level: 1 Description: The theft of user information (such as: documents, etc.) PSW Hazard Class: 2 Note: the behavior of a stolen password DL Hazard Class: 3 Description: Download and run the virus First, determine the terms: Not out of any adjustable interface, logic functions are: to download files from a Web site loaded or run. Second, the logic condition caused by events: Event 1. Can not properly download the file download or a virus can not be determined. Operating Guidelines: The file can not meet the normal terms of the software identifies the functional components, identified as: Trojan.DL Event 2. The downloaded file is a virus Operation criteria: the downloaded file is a virus, identified as: Trojan.DL IMMSG Hazard Level: 4 Note: do not clear through a specific carrier or multiple carrier communication instant messaging (This behavior differs from the behavior of worms, the worm is to spread the virus themselves, just spread the word Trojan) MSNMSG Hazard Level: 5 Note: Communication through MSN instant messaging QQMSG Hazard level: 6 Description: OICQ spread through instant messaging ICQMSG Hazard Class: 7 Description: Instant Message through ICQ Communication UCMSG Hazard Class: 8 Description: UC spread through instant messaging Proxy Hazard Class: 9 Note: The infected computer as a proxy server Clicker Hazard level: 10 Note: Click on the specified page Determine the terms: Not out of any adjustable interface, the logic function is: click on a page. Operational guidelines: The file does not meet the normal terms of the software identifies the functional components, identified as: Trojan.Clicker. (The document identifies the functional components meet the normal terms of the software to refer to rogue software rogue software to determine the rules of decision) Dialer Hazard level: 12 Note: dial-up procedures to cheat Money Description: can not describe the purpose of their interests but in line with the basic characteristics of Trojans are not specifically described in sub-behavior AOL Named according to the original virus retained. Notifier Named according to the original virus retained. Virus Hazard Level: 4 Description: Chinese name - "virus infection" refers to the virus code attached to an infected host file (such as: PE files, DOS files under the COM, VBS file to run the macro with a file), so that the virus code in the infected host file is run to obtain the right to run the virus. Harm Hazard Level: 5 Description: Chinese name - "destructive process", which refers to not spread the infection does not run directly after the destruction of the local computer (such as: formatting the hard disk, a large number of _delete_d files, etc.) led to the local computer can not properly use the program. Dropper Hazard level: 6 Description: Chinese name - "release the virus program" means not normal or self-extracting installation program, and run and they run after the release of the virus. One. Dropper determine the terms: Not out of any adjustable interface, logic functions: the release of documents from the load or run. II. Logical condition caused by events: Event 1:. Release of the file is not a virus. Operation criteria: the release of the documents and Emancipator itself has no logical relationship and the file does not meet the normal terms of the software identifies the functional components, identified as: Droper Event 2: The files are virus free. Operation criteria: the release of the virus file, to determine the file is: Droper Hack Hazard Class: None Description: Chinese name - "hacking tools" refers to the local computer to attack other computers through the network tool. Exploit Description: Attack vulnerability detection tools DDoser Description: denial of service attack tool Flooder Description: flood attack tool Note: You can not clear with the hacker attacks and related software, you do not describe the specific sub-behaviors Spam Description: spam. Nuker Sniffer Spoofer Anti Note: to avoid killing the hacking tools Binder Hazard Class: None Description: a tool for virus binding Terms of normal software identifies functional components: the documents to be checked the body with the following information to identify the file is a normal function of the software components: file version information, software information (registry key, the installation directory) and so on. Host file Hosts file is a file type used by the virus, there is displayed attributes. The current host file has the following. JS Description: JavaScript script file Description VBS: VBScript Script File HTML Description: HTML file Java Description: Java's Class Files COM Description: Dos file under the Com EXE Description: Dos Exe file under the Boot Description: The hard disk or floppy disk boot sector Word Note: MS Word document company Excel note: MS Excel file the company's PE Note: PE files WinREG Description: Registry File Ruby Description: A script Python Description: A script BAT Description: BAT script IRC Description: IRC script Main Title The name of the virus by the analyst under the main body of the characteristics of the virus strings used by a particular act or platform to be compiled, and if not sure you can use the string "Agent" instead of the primary name, the file size less than 10k can be named as "Samll". Version Information The digital version only allows for the version information is not clear without version information. No owner name variants If the virus main types of behavior type, the host file type, the main names are the same, that is the same family of viruses, then the need to distinguish between different variants of the virus No record. If a version number is not enough to extend a maximum of three, and both are lowercase letters a-z, such as: aa, ab, aaa, aab and so on. Calculated by the system automatically, without manual input or _select_ion. Subsidiary Name The virus has the auxiliary function used in the paper can be run, usually added to the virus database as a virus, this type of virus records need to be affiliated with the virus name to distinguish between the main body of the virus records. There are several subsidiary name: Client Description: The back door of the control side KEY_HOOK Description: module for hooking keyboard API_HOOK Description: API for the modules attached Install Note: the module to install the virus Dll Note: File a dynamic library, and includes a variety of functions (Empty) Description: No sub name, this record is the main record of the virus No. subsidiary name variants If the virus main types of behavior type, the host file type, owner name, owner name variant number, subsidiary names are the same, that is the same family of viruses, then the need to distinguish between different variants of the virus No record. Variant number is not written the letters a-z, if not a version number can be expanded with a maximum of three, such as: aa, ab, aaa, aab and so on. Calculated by the system automatically, without manual input or _select_ion. Virus length Virus length field for the main type of behavior only type of infection (Virus) virus, the field value numbers. Field is 0, that the virus is variable length.
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Medical Dictionary
Viruses of animals, plants and microorganisms, destroy livestock and crops, can cause significant loss of national economy. Virus poses serious threat to human health, many infectious diseases such as influenza, measles, encephalitis, pneumonia, polio until by the virus. Some viruses can also cause animal tumors. Bacterial contamination in the fermentation industry taboo, threatening pesticides, antibiotics, enzymes, organic solvents such as fermentation and dairy production. Some viruses can be used to control pests and pathogens. Molecular biology of the virus is an important experimental material.
virus