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Virology
Virology is the Scientific method, scientific study of biological viruses. It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host (biology), host cell (biology), cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. The identification of the causative agent of tobacco mosaic disease (TMV) as a novel pathogen by Martinus Beijerinck (1898) is now acknowledged as being the history of virology, official beginning of the field of virology as a discipline distinct from bacteriology. He realized the source was neither a bacterial nor a fungal infection, but something completely different. Beijerinck used the word "virus" to describe the mysterious agent in his 'contagium vivum fluidum' ('contagious living fluid'). Rosalind Franklin proposed the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Pathogenesis
Viral pathogenesis is the study of the process and mechanisms by which viruses cause diseases in their target Host (biology), hosts, often at the cellular or molecular level. It is a specialized field of study in virology. Pathogenesis is a qualitative description of the process by which an initial infection causes disease. Viral disease is the sum of the effects of viral replication on the host and the host's subsequent immune response against the virus. Viruses are able to initiate infection, disperse throughout the body, and replicate due to specific virulence factors. There are several factors that affect pathogenesis. Some of these factors include virulence characteristics of the virus that is infecting. In order to cause disease, the virus must also overcome several inhibitory effects present in the host. Some of the inhibitory effects include distance, physical barriers and host defenses. These inhibitory effects may differ among individuals due to the inhibitory effects be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of List of virus species, virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or ''virions'', consisting of (i) genetic material, i.e., long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Virology
The history of virology – the scientific study of viruses and the infections they cause – began in the closing years of the 19th century. Although Edward Jenner and Louis Pasteur developed the first vaccines to protect against viral infections, they did not know that viruses existed. The first evidence of the existence of viruses came from experiments with filters that had pores small enough to retain bacteria. In 1892, Dmitri Ivanovsky used one of these filters to show that sap from a diseased tobacco plant remained infectious to healthy tobacco plants despite having been filtered. Martinus Beijerinck called the filtered, infectious substance a "virus" and this discovery is considered to be the beginning of virology. The subsequent discovery and partial characterization of bacteriophages by Frederick Twort and Félix d'Herelle further catalyzed the field, and by the early 20th century many viruses had been discovered. In 1926, Thomas Milton Rivers defined viruses as obliga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiology
Microbiology () is the branches of science, scientific study of microorganisms, those being of unicellular organism, unicellular (single-celled), multicellular organism, multicellular (consisting of complex cells), or non-cellular life, acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. The organisms that constitute the microbial world are characterized as either prokaryotes or eukaryotes; eukaryote, Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryote, prokaryotic organisms are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy for the isolation and identification of microorganisms. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martinus Beijerinck
Martinus Willem Beijerinck (, 16 March 1851 – 1 January 1931) was a Dutch microbiologist and botanist who was one of the founders of virology and environmental microbiology. He is credited with the co-discovery of viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almo ... (1898), which he called "''contagium vivum fluidum''". Life Early life and education Born in Amsterdam, Beijerinck studied at the Technical School of Delft, where he was awarded the degree of biology in 1872. He obtained his Doctor of Science degree from the University of Leiden in 1877. At the time, Delft, then a List of institutions using the term "institute of technology" or "polytechnic", Polytechnic, did not have the right to confer doctorates, so Leiden did this for them. He became a teacher in microb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Virology
Veterinary virology is the study of viruses in non-human animals. It is an important branch of veterinary medicine. Rhabdoviruses Rhabdoviruses are a diverse family of single stranded, negative sense RNA viruses that infect a wide range of hosts, from plants and insects, to fish and mammals. The ''Rhaboviridae'' family consists of six genera, two of which, cytorhabdoviruses and nucleorhabdoviruses, only infect plants. Novirhabdoviruses infect fish, and vesiculovirus, lyssavirus and ephemerovirus infect mammals, fish and invertebrates. The family includes pathogens such as rabies virus, vesicular stomatitis virus and potato yellow dwarf virus that are of public health, veterinary, and agricultural significance. Foot-and-mouth disease virus Foot-and-mouth disease virus (FMDV) is a member of the Aphthovirus genus in the Picornaviridae family and is the cause of foot-and-mouth disease in pigs, cattle, sheep and goats. It is a non-enveloped, positive strand, RNA virus. FMDV i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Virology
Plant viruses are viruses that have the potential to affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to vascular plants ("higher plants"). Many plant viruses are rod-shaped, with protein discs forming a tube surrounding the viral genome; isometric particles are another common structure. They rarely have an envelope. The great majority have an RNA genome, which is usually small and single stranded (ss), but some viruses have double-stranded (ds) RNA, ssDNA or dsDNA genomes. Although plant viruses are not as well understood as their animal counterparts, one plant virus has become very recognizable: ''tobacco mosaic virus'' (TMV), the first virus to be discovered. This and other viruses cause an estimated US$60 billion loss in crop yields worldwide each year. Plant viruses are grouped into 73 genera and 49 families. However, these figure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dmitri Ivanovsky
Dmitri Iosifovich Ivanovsky (alternative spelling ''Dmitrii'' or ''Dmitry Iwanowski''; ; 28 October 1864 – 20 June 1920) was a Russian botanist, the co-discoverer of :viruses (1892), and one of the founders of virology. Life Ivanovsky was born in the village of Nizy, Gdov Uyezd. He studied at the University of Saint Petersburg under Andrei Famintsyn in 1887, when he was sent to Ukraine and Bessarabia to investigate a tobacco disease causing great damage to plantations located there at the time. Three years later, he was assigned to look into a similar disease occurrence of tobacco plants, this time raging in the Crimea region. He discovered that both incidents of disease were caused by an extremely minuscule infectious agent, capable of permeating porcelain Pasteur-Chamberland filters, something which bacteria could never do. He described his findings in an article (1892) and a dissertation (1902). Then he worked at the Imperial University of Warsaw and at Donskoy Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamberland Filter
A Chamberland filter, also known as a Pasteur–Chamberland filter, is a porcelain water filter invented by Charles Chamberland in 1884. It was developed after Henry Doulton's ceramic water filter of 1827. It is similar to the Berkefeld filter in principle. Design The filter consists of a permeable unglazed porcelain tube (called bisque) that contains a ring of enameled porcelain through which the inflow pipe fits. The core of the porcelain is made up of a metal pipe with holes through which water flows out and is collected. Inflow is pressurized so filtration occurs under force. There are 13 types: ''L1'' to ''L13''. L1 filters have the coarsest pore size while L13 have the finest. Usefulness The Pasteur-Chamberland filter is as useful as other ceramic and porcelain filters. It is a good bacterial water filter used mainly as a high volume water filter.Textbook of Microbiology by Ananthanarayan and Panikar, The filter works more quickly when the water supplied is und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rabies
Rabies is a viral disease that causes encephalitis in humans and other mammals. It was historically referred to as hydrophobia ("fear of water") because its victims panic when offered liquids to drink. Early symptoms can include fever and abnormal sensations at the site of exposure. These symptoms are followed by one or more of the following symptoms: nausea, vomiting, violent movements, uncontrolled excitement, fear of water, an inability to move parts of the body, confusion, and loss of consciousness. Once symptoms appear, the result is virtually always death. The time period between contracting the disease and the start of symptoms is usually one to three months but can vary from less than one week to more than one year. The time depends on the distance the virus must travel along Peripheral nervous system, peripheral nerves to reach the central nervous system. Rabies is caused by lyssaviruses, including the rabies virus and Australian bat lyssavirus. It is spread when an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microorganism
A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in Jain literature authored in 6th-century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Microorganisms are extremely diverse, representing most unicellular organisms in all three domains of life: two of the three domains, Archaea and Bacteria, only contain microorganisms. The third domain, Eukaryota, includes all multicellular o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobacco Mosaic Virus
Tobacco mosaic virus (TMV) is a positive-sense single-stranded RNA virus species in the genus '' Tobamovirus'' that infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns, such as "mosaic"-like mottling and discoloration on the leaves (hence the name). TMV was the first virus to be discovered. Although it was known from the late 19th century that a non-bacterial infectious disease was damaging tobacco crops, it was not until 1930 that the infectious agent was determined to be a virus. It is the first pathogen identified as a virus. The virus was crystallised by Wendell Meredith Stanley. It has a similar size to the largest synthetic molecule, known as PG5 with comparable length and diameter. History In 1886, Adolf Mayer first described the tobacco mosaic disease that could be transferred between plants, similar to bacterial infections. In 1892, Dmitri Ivanovsky gave the first concrete e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
