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93-404: Zaire ebolavirus , more commonly known as Ebola virus ( / i ˈ b oʊ l ə , ɪ -/ ; EBOV ), is one of six known species within the genus Ebolavirus . Four of the six known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals , known as Ebola virus disease (EVD). Ebola virus has caused the majority of human deaths from EVD, and

186-570: A US National Institutes of Health / National Institute of Allergy and Infectious Diseases Category A Priority Pathogen, US CDC Centers for Disease Control and Prevention Category A Bioterrorism Agent , and a Biological Agent for Export Control by the Australia Group . EBOV carries a negative-sense RNA genome in virions that are cylindrical/tubular, and contain viral envelope , matrix, and nucleocapsid components. The overall cylinders are generally approximately 80  nm in diameter, and have

279-500: A basis for a rapid field diagnostic assay. Being acellular, viruses such as Ebola do not replicate through any type of cell division; rather, they use a combination of host- and virally encoded enzymes, alongside host cell structures, to produce multiple copies of themselves. These then self-assemble into viral macromolecular structures in the host cell. The virus completes a set of steps when infecting each individual cell. The virus begins its attack by attaching to host receptors through

372-643: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as

465-420: A lens optical system or a fibre optic light-guide to the sensor of a digital camera . Direct electron detectors have no scintillator and are directly exposed to the electron beam, which addresses some of the limitations of scintillator-coupled cameras. The resolution of TEMs is limited primarily by spherical aberration , but a new generation of hardware correctors can reduce spherical aberration to increase

558-621: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,

651-489: A map of the angles of the electrons leaving the sample is produced. The advantages of electron diffraction over X-ray crystallography are primarily in the size of the crystals. In X-ray crystallography, crystals are commonly visible by the naked eye and are generally in the hundreds of micrometers in length. In comparison, crystals for electron diffraction must be less than a few hundred nanometers in thickness, and have no lower boundary of size. Additionally, electron diffraction

744-420: A more general morphologic characteristic of filoviruses (alongside their GP-decorated viral envelope, RNA nucleocapsid, etc.). Each virion contains one molecule of linear, single-stranded, negative-sense RNA, 18,959 to 18,961 nucleotides in length. The 3′ terminus is not polyadenylated and the 5′ end is not capped. This viral genome codes for seven structural proteins and one non-structural protein. The gene order

837-422: A person during the progression of disease and in the reservoir among the local human population. The observed mutation rate of 2.0 x 10 substitutions per site per year is as fast as that of seasonal influenza . There are two candidates for host cell entry proteins. The first is a cholesterol transporter protein, the host-encoded Niemann–Pick C1 ( NPC1 ), which appears to be essential for entry of Ebola virions into

930-453: A possible mode to make some individuals resistant to this deadly viral disease. The same studies described similar results regarding NPC1's role in virus entry for Marburg virus , a related filovirus . A further study has also presented evidence that NPC1 is the critical receptor mediating Ebola infection via its direct binding to the viral GP, and that it is the second "lysosomal" domain of NPC1 that mediates this binding. The second candidate

1023-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for

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1116-441: A replicate of which is shown in the figure, used two magnetic lenses to achieve higher magnifications, the first electron microscope. (Max Knoll died in 1969, so did not receive a share of the 1986 Nobel prize for the invention of electron microscopes.) Apparently independent of this effort was work at Siemens-Schuckert by Reinhold Rüdenberg . According to patent law (U.S. Patent No. 2058914 and 2070318, both filed in 1932), he

1209-410: A sample. A few examples are outlined below, but this should not be considered an exhaustive list. The choice of workflow will be highly dependent on the application and the requirements of the corresponding scientific questions, such as resolution, volume, nature of the target molecule, etc. For example, images from light and electron microscopy of the same region of a sample can be overlaid to correlate

1302-473: A series of outbreaks among humans in Central Africa in 2001–2003. Zaire ebolavirus – Makona variant caused the 2014 West Africa outbreak. The outbreak was characterized by the longest instance of human-to-human transmission of the viral species. Pressures to adapt to the human host were seen at this time, however, no phenotypic changes in the virus (such as increased transmission, increased immune evasion by

1395-550: A single brightness value per pixel, with the results usually rendered in greyscale . However, often these images are then colourized through the use of feature-detection software, or simply by hand-editing using a graphics editor. This may be done to clarify structure or for aesthetic effect and generally does not add new information about the specimen. Electron microscopes are now frequently used in more complex workflows, with each workflow typically using multiple technologies to enable more complex and/or more quantitative analyses of

1488-509: A specimen surface (SEM with secondary electrons) has also increasingly expanded into the depth of samples. An early example of these ‘ volume EM ’ workflows was simply to stack TEM images of serial sections cut through a sample. The next development was virtual reconstruction of a thick section (200-500 nm) volume by backprojection of a set of images taken at different tilt angles - TEM tomography . To acquire volume EM datasets of larger depths than TEM tomography (micrometers or millimeters in

1581-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;

1674-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and

1767-539: A virally encoded glycoprotein (GP) projecting as 7–10 nm long spikes from its lipid bilayer surface. The cylinders are of variable length, typically 800 nm, but sometimes up to 1000 nm long. The outer viral envelope of the virion is derived by budding from domains of host cell membrane into which the GP spikes have been inserted during their biosynthesis. Individual GP molecules appear with spacings of about 10 nm. Viral proteins VP40 and VP24 are located between

1860-470: Is 3′ – leader – NP – VP35 – VP40 – GP/sGP – VP30 – VP24 – L – trailer – 5′; with the leader and trailer being non-transcribed regions, which carry important signals to control transcription, replication, and packaging of the viral genomes into new virions. Sections of the NP, VP35 and the L genes from filoviruses have been identified as endogenous in the genomes of several groups of small mammals. [REDACTED] It

1953-642: Is TIM-1 (a.k.a. HAVCR1 ). TIM-1 was shown to bind to the receptor binding domain of the EBOV glycoprotein, to increase the receptivity of Vero cells . Silencing its effect with siRNA prevented infection of Vero cells . TIM1 is expressed in tissues known to be seriously impacted by EBOV lysis (trachea, cornea, and conjunctiva). A monoclonal antibody against the IgV domain of TIM-1, ARD5, blocked EBOV binding and infection. Together, these studies suggest NPC1 and TIM-1 may be potential therapeutic targets for an Ebola anti-viral drug and as

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2046-463: Is a single-stranded RNA, approximately 19,000 nucleotides long. It encodes seven structural proteins : nucleoprotein (NP), polymerase cofactor (VP35), (VP40), GP, transcription activator (VP30), VP24 , and RNA-dependent RNA polymerase (L). Because of its high fatality rate (up to 83 to 90 percent), EBOV is also listed as a select agent , World Health Organization Risk Group 4 Pathogen (requiring Biosafety Level 4-equivalent containment ),

2139-596: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms

2232-458: Is done on a TEM, which can also be used to obtain many other types of information, rather than requiring a separate instrument. Samples for electron microscopes mostly cannot be observed directly. The samples need to be prepared to stabilize the sample and enhance contrast. Preparation techniques differ vastly in respect to the sample and its specific qualities to be observed as well as the specific microscope used. To prevent charging and enhance

2325-514: Is part of the genus Ebolavirus , family Filoviridae , order Mononegavirales . The name "Ebola virus" is derived from the Ebola River —a river that was at first thought to be in close proximity to the area in Democratic Republic of Congo , previously called Zaire , where the 1976 Zaire Ebola virus outbreak occurred—and the taxonomic suffix virus . In 1998, the virus name

2418-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,

2511-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with

2604-403: Is the inventor of the electron microscope, but it is not clear when he had a working instrument. He stated in a very brief article in 1932 that Siemens had been working on this for some years before the patents were filed in 1932, claiming that his effort was parallel to the university development. He died in 1961, so similar to Max Knoll, was not eligible for a share of the 1986 Nobel prize. In

2697-422: Is the single member of the species Zaire ebolavirus , which is assigned to the genus Ebolavirus , family Filoviridae , order Mononegavirales . The members of the species are called Zaire ebolaviruses. The natural reservoir of Ebola virus is believed to be bats , particularly fruit bats , and it is primarily transmitted between humans and from animals to humans through body fluids . The EBOV genome

2790-500: Is to use BSE SEM to image the block surface instead of the section, after each section has been removed. By this method, an ultramicrotome installed in an SEM chamber can increase automation of the workflow; the specimen block is loaded in the chamber and the system programmed to continuously cut and image through the sample. This is known as serial block face SEM. A related method uses focused ion beam milling instead of an ultramicrotome to remove sections. In these serial imaging methods,

2883-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to

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2976-600: The International Committee on Taxonomy of Viruses (ICTV), the name Zaire ebolavirus is always to be capitalized , italicized , and to be preceded by the word "species". The names of its members (Zaire ebolaviruses) are to be capitalized, are not italicized, and used without articles . A virus of the genus Ebolavirus is a member of the species Zaire ebolavirus if: Zaire ebolavirus diverged from its ancestors between 1960 and 1976. The genetic diversity of Ebolavirus remained constant before 1900. Then, around

3069-799: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;

3162-419: The nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,

3255-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,

3348-784: The scanning electron microscope . Siemens produced the first commercial electron microscope in 1938. The first North American electron microscopes were constructed in the 1930s, at the Washington State University by Anderson and Fitzsimmons and at the University of Toronto by Eli Franklin Burton and students Cecil Hall, James Hillier , and Albert Prebus. Siemens produced a transmission electron microscope (TEM) in 1939. Although current transmission electron microscopes are capable of two million times magnification, as scientific instruments they remain similar but with improved optics. In

3441-409: The transmission electron microscope (TEM), uses a high voltage electron beam to illuminate the specimen and create an image. An electron beam is produced by an electron gun , with the electrons typically having energies in the range 20 to 400 keV, focused by electromagnetic lenses, and transmitted through the specimen. When it emerges from the specimen, the electron beam carries information about

3534-447: The 1940s, high-resolution electron microscopes were developed, enabling greater magnification and resolution. By 1965, Albert Crewe at the University of Chicago introduced the scanning transmission electron microscope using a field emission source , enabling scanning microscopes at high resolution. By the early 1980s improvements in mechanical stability as well as the use of higher accelerating voltages enabled imaging of materials at

3627-602: The 1960s, most likely due to climate change or human activities, the genetic diversity of the virus dropped rapidly and most lineages became extinct. As the number of susceptible hosts declines, so does the effective population size and its genetic diversity. This genetic bottleneck effect has implications for the species' ability to cause Ebola virus disease in human hosts. A recombination event between Zaire ebolavirus lineages likely took place between 1996 and 2001 in wild apes giving rise to recombinant progeny viruses. These recombinant viruses appear to have been responsible for

3720-456: The Philippines have been reported to be infected with Reston virus , so other interim or amplifying hosts may exist. Ebola virus outbreaks tend to occur when temperatures are lower and humidity is higher than usual for Africa. Even after a person recovers from the acute phase of the disease, Ebola virus survives for months in certain organs such as the eyes and testes. Zaire ebolavirus is one of

3813-413: The above links. This article contains some general information mainly about transmission electron microscopes. Many developments laid the groundwork of the electron optics used in microscopes. One significant step was the work of Hertz in 1883 who made a cathode-ray tube with electrostatic and magnetic deflection, demonstrating manipulation of the direction of an electron beam. Others were focusing of

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3906-399: The atomic scale. In the 1980s, the field emission gun became common for electron microscopes, improving the image quality due to the additional coherence and lower chromatic aberrations. The 2000s were marked by advancements in aberration-corrected electron microscopy, allowing for significant improvements in resolution and clarity of images. The original form of the electron microscope,

3999-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of

4092-420: The cell. Ebola virus is a zoonotic pathogen. Intermediary hosts have been reported to be "various species of fruit bats ... throughout central and sub-Saharan Africa". Evidence of infection in bats has been detected through molecular and serologic means. However, ebolaviruses have not been isolated in bats. End hosts are humans and great apes, infected through bat contact or through other end hosts. Pigs in

4185-413: The cell. As viral protein levels rise, a switch occurs from translation to replication. Using the negative-sense genomic RNA as a template, a complementary +ssRNA is synthesized; this is then used as a template for the synthesis of new genomic (-)ssRNA, which is rapidly encapsidated. The newly formed nucleocapsids and envelope proteins associate at the host cell's plasma membrane; budding occurs, destroying

4278-578: The data from the two modalities. This is commonly used to provide higher resolution contextual EM information about a fluorescently labelled structure. This correlative light and electron microscopy ( CLEM ) is one of a range of correlative workflows now available. Another example is high resolution mass spectrometry (ion microscopy), which has been used to provide correlative information about subcellular antibiotic localisation, data that would be difficult to obtain by other means. The initial role of electron microscopes in imaging two-dimensional slices (TEM) or

4371-605: The disease in his daily log: The illness is characterized with a high temperature of about 39°C, hematemesis , diarrhea with blood, retrosternal abdominal pain, prostration with "heavy" articulations, and rapid evolution death after a mean of three days. Since the first recorded clinical description of the disease during 1976 in Zaire, the recent Ebola outbreak that started in March 2014, in addition, reached epidemic proportions and has killed more than 8000 people as of January 2015. This outbreak

4464-432: The disease in humans varies widely, from rapid fatality to mild illness or even asymptomatic response. Studies of outbreaks in the late twentieth century failed to find a correlation between the disease severity and the genetic nature of the virus. Hence the variability in the severity of illness was suspected to correlate with genetic differences in the victims. This has been difficult to study in animal models that respond to

4557-458: The electron beam interacts with the specimen, it loses energy by a variety of mechanisms. These interactions lead to, among other events, emission of low-energy secondary electrons and high-energy backscattered electrons, light emission ( cathodoluminescence ) or X-ray emission, all of which provide signals carrying information about the properties of the specimen surface, such as its topography and composition. The image displayed by SEM represents

4650-405: The electron beam, for instance focusing them to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light, electron microscopes have a much higher resolution of about 0.1 nm, which compares to about 200 nm for light microscopes . Electron microscope may refer to: Additional details can be found in

4743-407: The electrons by an axial magnetic field by Emil Wiechert in 1899, improved oxide-coated cathodes which produced more electrons by Arthur Wehnelt in 1905 and the development of the electromagnetic lens in 1926 by Hans Busch . According to Dennis Gabor , the physicist Leó Szilárd tried in 1928 to convince him to build an electron microscope, for which Szilárd had filed a patent. To this day

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4836-505: The electrons hit the specimen in the STEM, but afterward in the TEM. The STEMs use of SEM-like beam rastering simplifies annular dark-field imaging , and other analytical techniques, but also means that image data is acquired in serial rather than in parallel fashion. The SEM produces images by probing the specimen with a focused electron beam that is scanned across the specimen ( raster scanning ). When

4929-485: The envelope and the nucleocapsid (see following), in the matrix space . At the center of the virion structure is the nucleocapsid , which is composed of a series of viral proteins attached to an 18–19 kb linear, negative-sense RNA without 3′- polyadenylation or 5′-capping (see following); the RNA is helically wound and complexed with the NP, VP35, VP30, and L proteins; this helix has a diameter of 80 nm. The overall shape of

5022-410: The following year, 1933, Ruska and Knoll built the first electron microscope that exceeded the resolution of an optical (light) microscope. Four years later, in 1937, Siemens financed the work of Ernst Ruska and Bodo von Borries , and employed Helmut Ruska , Ernst's brother, to develop applications for the microscope, especially with biological specimens. Also in 1937, Manfred von Ardenne pioneered

5115-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this

5208-633: The four ebolaviruses known to cause disease in humans. It has the highest case-fatality rate of these ebolaviruses, averaging 83 percent since the first outbreaks in 1976, although a fatality rate of up to 90 percent was recorded in one outbreak in the Republic of the Congo between December 2002 and April 2003. There have also been more outbreaks of Zaire ebolavirus than of any other ebolavirus. The first outbreak occurred on 26 August 1976 in Yambuku . The first recorded case

5301-727: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,

5394-421: The glycoprotein (GP) surface peplomer and is endocytosed into macropinosomes in the host cell. To penetrate the cell, the viral membrane fuses with vesicle membrane, and the nucleocapsid is released into the cytoplasm . Encapsidated, negative-sense genomic ssRNA is used as a template for the synthesis (3'–5') of polyadenylated, monocistronic mRNAs and, using the host cell's ribosomes, tRNA molecules, etc.,

5487-471: The host cell and for its ultimate replication. In one study, mice with one copy of the NPC1 gene removed showed an 80 percent survival rate fifteen days after exposure to mouse-adapted Ebola virus, while only 10 percent of unmodified mice survived this long. In another study, small molecules were shown to inhibit Ebola virus infection by preventing viral envelope glycoprotein (GP) from binding to NPC1. Hence, NPC1

5580-711: The issue of who invented the transmission electron microscope is controversial. In 1928, at the Technische Hochschule in Charlottenburg (now Technische Universität Berlin ), Adolf Matthias (Professor of High Voltage Technology and Electrical Installations) appointed Max Knoll to lead a team of researchers to advance research on electron beams and cathode-ray oscilloscopes. The team consisted of several PhD students including Ernst Ruska . In 1931, Max Knoll and Ernst Ruska successfully generated magnified images of mesh grids placed over an anode aperture. The device,

5673-628: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,

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5766-413: The lizard genus Anolis has been suggested to be broken down into 8 or so different genera which would bring its ~400 species to smaller, more manageable subsets. Electron microscopy An electron microscope is a microscope that uses a beam of electrons as a source of illumination. They use electron optics that are analogous to the glass lenses of an optical light microscope to control

5859-440: The mRNA is translated into individual viral proteins. These viral proteins are processed: a glycoprotein precursor (GP0) is cleaved to GP1 and GP2, which are then heavily glycosylated using cellular enzymes and substrates. These two molecules assemble, first into heterodimers, and then into trimers to give the surface peplomers. Secreted glycoprotein (sGP) precursor is cleaved to sGP and delta peptide, both of which are released from

5952-728: The molecules that make up air would scatter the electrons. An exception is liquid-phase electron microscopy using either a closed liquid cell or an environmental chamber, for example, in the environmental scanning electron microscope , which allows hydrated samples to be viewed in a low-pressure (up to 20  Torr or 2.7 kPa) wet environment. Various techniques for in situ electron microscopy of gaseous samples have been developed. Scanning electron microscopes operating in conventional high-vacuum mode usually image conductive specimens; therefore non-conductive materials require conductive coating (gold/palladium alloy, carbon, osmium, etc.). The low-voltage mode of modern microscopes makes possible

6045-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus

6138-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this

6231-714: The observation of non-conductive specimens without coating. Non-conductive materials can be imaged also by a variable pressure (or environmental) scanning electron microscope. Small, stable specimens such as carbon nanotubes , diatom frustules and small mineral crystals (asbestos fibres, for example) require no special treatment before being examined in the electron microscope. Samples of hydrated materials, including almost all biological specimens, have to be prepared in various ways to stabilize them, reduce their thickness (ultrathin sectioning) and increase their electron optical contrast (staining). These processes may result in artifacts , but these can usually be identified by comparing

6324-678: The output is essentially a sequence of images through a specimen block that can be digitally aligned in sequence and thus reconstructed into a volume EM dataset. The increased volume available in these methods has expanded the capability of electron microscopy to address new questions, such as mapping neural connectivity in the brain, and membrane contact sites between organelles. Electron microscopes are expensive to build and maintain. Microscopes designed to achieve high resolutions must be housed in stable buildings (sometimes underground) with special services such as magnetic field canceling systems. The samples largely have to be viewed in vacuum , as

6417-526: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for

6510-473: The resolution in high-resolution transmission electron microscopy (HRTEM) to below 0.5 angstrom (50 picometres ), enabling magnifications above 50 million times. The ability of HRTEM to determine the positions of atoms within materials is useful for nano-technologies research and development. The STEM rasters a focused incident probe across a specimen. The high resolution of the TEM is thus possible in STEM. The focusing action (and aberrations) occur before

6603-466: The same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but the French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or

6696-408: The scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of a species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in

6789-454: The signal in SEM, non-conductive samples (e.g. biological samples as in figure) can be sputter-coated in a thin film of metal. Materials to be viewed in a transmission electron microscope may require processing to produce a suitable sample. The technique required varies depending on the specimen and the analysis required: In their most common configurations, electron microscopes produce images with

6882-403: The species designation Zaire ebolavirus . The prototype Ebola virus, variant Mayinga (EBOV/May), was named for Mayinga N'Seka, a nurse who died during the 1976 Zaire outbreak. The name Zaire ebolavirus is derived from Zaire and the taxonomic suffix ebolavirus (which denotes an ebolavirus species and refers to the Ebola River ). According to the rules for taxon naming established by

6975-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,

7068-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being

7161-439: The structure of the specimen that is magnified by lenses of the microscope. The spatial variation in this information (the "image") may be viewed by projecting the magnified electron image onto a detector . For example, the image may be viewed directly by an operator using a fluorescent viewing screen coated with a phosphor or scintillator material such as zinc sulfide . A high-resolution phosphor may also be coupled by means of

7254-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for

7347-566: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up

7440-564: The varying intensity of any of these signals into the image in a position corresponding to the position of the beam on the specimen when the signal was generated. SEMs are different from TEMs in that they use electrons with much lower energy, generally below 20 keV, while TEMs generally use electrons with energies in the range of 80-300 keV. Thus, the electron sources and optics of the two microscopes have different designs, and they are normally separate instruments. Transmission electron microscopes can be used in electron diffraction mode where

7533-466: The virions after purification and visualization (e.g., by ultracentrifugation and electron microscopy , respectively) varies considerably; simple cylinders are far less prevalent than structures showing reversed direction, branches, and loops (e.g., U-, shepherd's crook -, 9-, or eye bolt -shapes, or other or circular/coiled appearances), the origin of which may be in the laboratory techniques applied. The characteristic "threadlike" structure is, however,

7626-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in

7719-690: The virus that includes fatality from hemorrhagic fever. In December 2016, a study found the VSV-EBOV vaccine to be 70–100% effective against the Zaire ebola virus (not the Sudan ebolavirus ), making it the first vaccine against the disease. VSV-EBOV was approved by the U.S. Food and Drug Administration in December 2019. Ebola virus was first identified as a possible new "strain" of Marburg virus in 1976. The International Committee on Taxonomy of Viruses (ICTV) identifies Ebola virus as species Zaire ebolavirus , which

7812-473: The virus were EBOV-Z (for "Ebola virus Zaire") and ZEBOV (for "Zaire Ebola virus" or " Zaire ebolavirus "). In 2011, the ICTV explicitly rejected a proposal (2010.010bV) to recognize this name, as ICTV does not designate names for subtypes, variants, strains, or other subspecies level groupings. At present, ICTV does not officially recognize "Ebola virus" as a taxonomic rank, but rather continues to use and recommend only

7905-412: The virus with hemorrhagic fever in a similar manner as humans, because typical mouse models do not so respond, and the required large numbers of appropriate test subjects are not easily available. In late October 2014, a publication reported a study of the response to a mouse-adapted strain of Zaire ebolavirus presented by a genetically diverse population of mice that was bred to have a range of responses to

7998-471: The virus) were seen. Genus The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of

8091-443: The z axis), a series of images taken through the sample depth can be used. For example, ribbons of serial sections can be imaged in a TEM as described above, and when thicker sections are used, serial TEM tomography can be used to increase the z-resolution. More recently, back scattered electron (BSE) images can be acquired of a larger series of sections collected on silicon wafers, known as SEM array tomography. An alternative approach

8184-466: Was Mabalo Lokela, a 44‑year-old schoolteacher. The symptoms resembled malaria , and subsequent patients received quinine . Transmission has been attributed to reuse of unsterilized needles and close personal contact, body fluids and places where the person has touched. During the 1976 Ebola outbreak in Zaire , Ngoy Mushola travelled from Bumba to Yambuku , where he recorded the first clinical description of

8277-478: Was centered in West Africa, an area that had not previously been affected by the disease. The toll was particularly grave in three countries: Guinea, Liberia, and Sierra Leone. A few cases were also reported in countries outside of West Africa, all related to international travelers who were exposed in the most affected regions and later showed symptoms of Ebola fever after reaching their destinations. The severity of

8370-446: Was changed to "Zaire Ebola virus" and in 2002 to species Zaire ebolavirus . However, most scientific articles continued to refer to "Ebola virus" or used the terms "Ebola virus" and " Zaire ebolavirus " in parallel. Consequently, in 2010, a group of researchers recommended that the name "Ebola virus" be adopted for a subclassification within the species Zaire ebolavirus , with the corresponding abbreviation EBOV. Previous abbreviations for

8463-684: Was found that 472 nucleotides from the 3' end and 731 nucleotides from the 5' end are sufficient for replication of a viral "minigenome", though not sufficient for infection. Virus sequencing from 78 patients with confirmed Ebola virus disease, representing more than 70% of cases diagnosed in Sierra Leone from late May to mid-June 2014, provided evidence that the 2014 outbreak was no longer being fed by new contacts with its natural reservoir. Using third-generation sequencing technology, investigators were able to sequence samples as quickly as 48 hours. Like other RNA viruses, Ebola virus mutates rapidly, both within

8556-416: Was shown to be critical to entry of this filovirus , because it mediates infection by binding directly to viral GP. When cells from Niemann–Pick Type C individuals lacking this transporter were exposed to Ebola virus in the laboratory, the cells survived and appeared impervious to the virus, further indicating that Ebola relies on NPC1 to enter cells; mutations in the NPC1 gene in humans were conjectured as

8649-460: Was the cause of the 2013–2016 epidemic in western Africa , which resulted in at least 28,646 suspected cases and 11,323 confirmed deaths. Ebola virus and its genus were both originally named for Zaire (now the Democratic Republic of the Congo ), the country where it was first described , and was at first suspected to be a new "strain" of the closely related Marburg virus . The virus was renamed "Ebola virus" in 2010 to avoid confusion. Ebola virus

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