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Acceleration
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See also
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See also
Acceleration (differential geometry)
Four-vector: making the connection between space and time explicit
Gravitational acceleration
Inertia
Orders of magnitude (acceleration)
Shock (mechanics)
Shock and vibration data logger measuring 3-axis acceleration
Space travel using constant acceleration
Specific force
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Acceleration
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References
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References
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Acceleration
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External links
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External links
Acceleration Calculator Simple acceleration unit converter
Category:Dynamics (mechanics)
Category:Kinematic properties
Category:Vector physical quantities
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Acceleration
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Table of Content
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Short description, Definition and properties, Average acceleration, Instantaneous acceleration, Units, Other forms, Tangential and centripetal acceleration, Special cases, Uniform acceleration, Circular motion, Coordinate systems, Relation to relativity, Special relativity, General relativity, Conversions, See also, References, External links
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Conservation and restoration of cultural property
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short description
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right|thumb|Removal of adherent surface deposits by physical chemical means (by cotton swab) at Church of Sucevița Monastery, burial chamber, in Suceava, Romania
right|thumb|Conservation of the Horses of Saint Mark (Venice)
The conservation and restoration of cultural property focuses on protection and care of cultural property (tangible cultural heritage), including artworks, architecture, archaeology, and museum collections. Conservation activities include preventive conservation, examination, documentation, research, treatment, and education. This field is closely allied with conservation science, curators and registrars.
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Conservation and restoration of cultural property
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Definition
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Definition
right|thumb|Revision and conservation of the Holy Trinity Column in Olomouc (Czech Republic) in 2006
Conservation of cultural property involves protection and restoration using "any methods that prove effective in keeping that property in as close to its original condition as possible for as long as possible." Conservation of cultural heritage is often associated with art collections and museums and involves collection care and management through tracking, examination, documentation, exhibition, storage, preventive conservation, and restoration.
The scope has widened from art conservation, involving protection and care of artwork and architecture, to conservation of cultural heritage, also including protection and care of a broad set of other cultural and historical works. Conservation of cultural heritage can be described as a type of ethical stewardship.
It may broadly be divided into:
Conservation and restoration of movable cultural property
Conservation and restoration of immovable cultural property
Conservation of cultural property applies simple ethical guidelines:
Minimal intervention;
Appropriate materials and reversible methods;
Full documentation of all work undertaken.
Often there are compromises between preserving appearance, maintaining original design and material properties, and ability to reverse changes. Reversibility is now emphasized so as to reduce problems with future treatment, investigation, and use.
In order for conservators to decide upon an appropriate conservation strategy and apply their professional expertise accordingly, they must take into account views of the stakeholder, the values, artist's intent, meaning of the work, and the physical needs of the material.
Cesare Brandi in his Theory of Restoration, describes restoration as "the methodological moment in which the work of art is appreciated in its material form and in its historical and aesthetic duality, with a view to transmitting it to the future".
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Conservation and restoration of cultural property
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History and science
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History and science
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Conservation and restoration of cultural property
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Key dates
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Key dates
Some consider the tradition of conservation of cultural heritage in Europe to have begun in 1565 with the restoration of the Sistine Chapel frescoes, but more ancient examples include the work of Cassiodorus.
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Conservation and restoration of cultural property
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Brief history
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Brief history
thumb|An early video showing some activities in a conservation laboratory at the Rijksmuseum
thumb|A temporary windowed partition along restoration work area in the cloister of the Church of St. Trophime, Arles
The care of cultural heritage has a long history, one that was primarily aimed at fixing and mending objects for their continued use and aesthetic enjoyment.Pye, E, 2001. Caring for the Past: Issues in Conservation for Archaeology and Museums. London: James and James Until the early 20th century, artists were normally the ones called upon to repair damaged artworks. During the 19th century, however, the fields of science and art became increasingly intertwined as scientists such as Michael Faraday began to study the damaging effects of the environment to works of art. Louis Pasteur carried out scientific analysis on paint as well. However, perhaps the first organized attempt to apply a theoretical framework to the conservation of cultural heritage came with the founding in the United Kingdom of the Society for the Protection of Ancient Buildings in 1877. The society was founded by William Morris and Philip Webb, both of whom were deeply influenced by the writings of John Ruskin. During the same period, a French movement with similar aims was being developed under the direction of Eugène Viollet-le-Duc, an architect and theorist, famous for his restorations of medieval buildings.
thumb|Since 1998, Harvard University wraps some of the valuable statues on its campus, such as this "Chinese stele", with waterproof covers every winter, in order to protect them from erosion caused by acid rain.
Conservation of cultural heritage as a distinct field of study initially developed in Germany, where in 1888 Friedrich Rathgen became the first chemist to be employed by a Museum, the Koniglichen Museen, Berlin (Royal Museums of Berlin). He not only developed a scientific approach to the care of objects in the collections, but disseminated this approach by publishing a Handbook of Conservation in 1898. The early development of conservation of cultural heritage in any area of the world is usually linked to the creation of positions for chemists within museums. In British archaeology, key research and technical experimentation in conservation was undertaken by women such as Ione Gedye both in the field and in archaeological collections, particularly those of the Institute of Archaeology, London.
In the United Kingdom, pioneering research into painting materials and conservation, ceramics, and stone conservation was conducted by Arthur Pillans Laurie, academic chemist and Principal of Heriot-Watt University from 1900. Laurie's interests were fostered by William Holman Hunt. In 1924 the chemist Harold Plenderleith began to work at the British Museum with Alexander Scott in the recently created Research Laboratory, although he was actually employed by the Department of Scientific and Industrial Research in the early years. Plenderleith's appointment may be said to have given birth to the conservation profession in the UK, although there had been craftsmen in many museums and in the commercial art world for generations. This department was created by the museum to address the deteriorating condition of objects in the collection, damages which were a result of their being stored in the London Underground tunnels during the First World War. The creation of this department moved the focus for the development of conservation theory and practice from Germany to Britain, and made the latter a prime force in this fledgling field. In 1956 Plenderleith wrote a significant handbook called The Conservation of Antiquities and Works of Art, which supplanted Rathgen's earlier tome and set new standards for the development of art and conservation science.
In the United States, the development of conservation of cultural heritage can be traced to the Fogg Art Museum, and Edward Waldo Forbes, its director from 1909 to 1944. He encouraged technical investigation, and was Chairman of the Advisory Committee for the first technical journal, Technical Studies in the Field of the Fine Arts, published by the Fogg from 1932 to 1942. Importantly he also brought onto the museum staff chemists. Rutherford John Gettens was the first of such in the US to be permanently employed by an art museum. He worked with George L. Stout, the founder and first editor of Technical Studies. Gettens and Stout co-authored Painting Materials: A Short Encyclopaedia in 1942, reprinted in 1966. This compendium is still cited regularly. Only a few dates and descriptions in Gettens' and Stout's book are now outdated.Stoner, Joyce Hill. "Changing Approaches in Art Conservation: 1925 to the present". The publication exists in two editions. The earlier one is "Scientific Examination of Art: Modern Techniques on Conservation and Analysis" and was published by the National Academy of Sciences in 2003. The later edition of the publication is "Arthur M. Sackler Colloquia: Scientific Examination of Art: Modern Techniques in Conservation and Analysis". It was published by the National Academies Press in 2005.
George T. Oliver, of Oliver Brothers Art Restoration and Art Conservation-Boston
(Est. 1850 in New York City) invented the vacuum hot table for relining paintings in 1920s; he filed a patent for the table in 1937.Patent# 2,073,802 U.S. "Art of Oil Painting Restoration" , March 16, 1937. Patft1.uspto.gov. Retrieved on 2012-06-29. Taylor's prototype table, which he designed and constructed, is still in operation. Oliver Brothers is believed to be the first and the oldest continuously operating art restoration company in the United States.
The focus of conservation development then accelerated in Britain and America, and it was in Britain that the first International Conservation Organisations developed. The International Institute for Conservation of Historic and Artistic Works (IIC) was incorporated under British law in 1950 as "a permanent organization to co-ordinate and improve the knowledge, methods, and working standards needed to protect and preserve precious materials of all kinds." The rapid growth of conservation professional organizations, publications, journals, newsletters, both internationally and in localities, has spearheaded the development of the conservation profession, both practically and theoretically. Art historians and theorists such as Cesare Brandi have also played a significant role in developing conservation science theory. In recent years ethical concerns have been at the forefront of developments in conservation. Most significantly has been the idea of preventive conservation. This concept is based in part on the pioneering work by Garry Thomson CBE, and his book Museum Environment, first published in 1978. Thomson was associated with the National Gallery in London; it was here that he established a set of guidelines or environmental controls for the best conditions in which objects could be stored and displayed within the museum environment. Although his exact guidelines are no longer rigidly followed, they did inspire this field of conservation.
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Conservation and restoration of cultural property
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Conservation laboratories
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Conservation laboratories
right|thumb|The Lunder Conservation Center. Conservation staff for both the Smithsonian American Art Museum and the National Portrait Gallery are visible to the public through floor-to-ceiling glass walls that allow visitors to see firsthand all the techniques that conservators use to examine, treat and preserve artworks within a functioning conservation Laboratory.
Conservators routinely use chemical and scientific analysis for the examination and treatment of cultural works. The modern conservation laboratory uses equipment such as microscopes, spectrometers, and various x-ray regime instruments to better understand objects and their components. The data thus collected helps in deciding the conservation treatments to be provided to the object.
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Conservation and restoration of cultural property
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Ethics
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Ethics
The conservator's work is guided by ethical standards. These take the form of applied ethics. Ethical standards have been established across the world, and national and international ethical guidelines have been written. One such example is:
American Institute for Conservation Code of Ethics and Guidelines for Practice
Conservation OnLine provides resources on ethical issues in conservation, including examples of codes of ethics and guidelines for professional conduct in conservation and allied fields; and charters and treaties pertaining to ethical issues involving the preservation of cultural property.
As well as standards of practice conservators deal with wider ethical concerns, such as the debates as to whether all art is worth preserving.
Keeping up with the international contemporary scenario, recent concerns with sustainability in conservation have emerged. The common understanding that "the care of an artifact should not come at the undue expense of the environment" is generally well accepted within the community and is already contemplated in guidelines of diverse institutions related to the field.
thumb|Preserved historical quarter in Beirut Central District
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Conservation and restoration of cultural property
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Practice
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Practice
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Conservation and restoration of cultural property
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Preventive conservation
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Preventive conservation
Many cultural works are sensitive to environmental conditions such as temperature, humidity and exposure to visible light and ultraviolet radiation. These works must be protected in controlled environments where such variables are maintained within a range of damage-limiting levels. For example, watercolour paintings usually require shielding from sunlight to prevent fading of pigments.
Collections care is an important element of museum policy. It is an essential responsibility of members of the museum profession to create and maintain a protective environment for the collections in their care, whether in store, on display, or in transit. A museum should carefully monitor the condition of collections to determine when an artifact requires conservation work and the services of a qualified conservator.
right|thumb|Work of preventive conservation in a rock wall with prehistoric paintings at the Serra da Capivara National Park. The work consists of filling the cracks to prevent the fragmentation of the wall.
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Conservation and restoration of cultural property
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Interventive conservation and restoration
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Interventive conservation and restoration
right|thumb|Furniture conservation – Re-glueing loose element of solid nut marriage chest (probably Italy, 19th century)
right|thumb|Antique conservation – Re-painting of the frame by museum employee
A teaching programme of interventive conservation was established in the UK at the Institute of Archaeology by Ione Gedye, which is still teaching interventive conservators today.
A principal aim of a cultural conservator is to reduce the rate of deterioration of an object. Both non-interventive and interventive methodologies may be employed in pursuit of this goal. Interventive conservation refers to any direct interaction between the conservator and the material fabric of the object. Interventive actions are carried out for a variety of reasons, including aesthetic choices, stabilization needs for structural integrity, or cultural requirements for intangible continuity. Examples of interventive treatments include the removal of discolored varnish from a painting, the application of wax to a sculpture, and the washing and rebinding of a book. Ethical standards within the field require that the conservator fully justify interventive actions and carry out documentation before, during, and after the treatment.
One of the guiding principles of conservation of cultural heritage has traditionally been the idea of reversibility, that all interventions with the object should be fully reversible and that the object should be able to be returned to the state in which it was prior to the conservator's intervention. Although this concept remains a guiding principle of the profession, it has been widely critiqued within the conservation professionAndrew Oddy and Sara Carroll (eds). 1999. Reversibility – Does it Exist? British Museum Occasional Paper Number 135. London: British Museum. and is now considered by many to be "a fuzzy concept." Another important principle of conservation is that all alterations should be well documented and should be clearly distinguishable from the original object.
An example of a highly publicized interventive conservation effort would be the conservation work conducted on the Sistine Chapel.
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Conservation and restoration of cultural property
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Example of an archaeological discovery and restoration of a mural painting
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Example of an archaeological discovery and restoration of a mural painting
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Conservation and restoration of cultural property
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Examples of the restoration of an oil painting
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Examples of the restoration of an oil painting
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Conservation and restoration of cultural property
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Sustainable conservation
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Sustainable conservation
Recognising that conservation practices should not harm the environment, harm people, or contribute to global warming, the conservation-restoration profession has more recently focused on practices that reduce waste, reduce energy costs, and minimise the use of toxic or harmful solvents. A number of research projects, working groups, and other initiatives have explored how conservation can become a more environmentally sustainable profession. Sustainable conservation practices apply both to work within cultural institutions (e.g. museums, art galleries, archives, libraries, research centres and historic sites) as well as to businesses and private studios.
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Conservation and restoration of cultural property
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Choice of materials
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Choice of materials
Conservators and restorers use a wide variety of materials - in conservation treatments, and those used to safely transport, display and store cultural heritage items. These materials can include solvents, papers and boards, fabrics, adhesives and consolidants, plastics and foams, wood products, and many others. Stability and longevity are two important factors conservators consider when selecting materials; sustainability is becoming an increasingly important third. Examples of sustainable material choices and practices include:
Using biodegradable products or those with less environmental impact where possible;
Using 'green solvents' instead of more toxic alternatives, or treatment strategies that use much smaller amounts of solvents - for example, semi-rigid aqueous gels, emulsions or nano materials;
Preparing smaller amounts of material (e.g. adhesives) to avoid waste;
Observing recommended disposal protocols for chemicals, recyclable materials and compostable materials, particularly to avoid contamination of waterways;
Choosing protective work wear that can be washed or cleaned and reused, rather than disposable options;
Tracking stock quantities to avoid over-buying, especially for materials with expiration dates;
Using durable materials for packing that may be washed and re-used, such as Tyvek or Mylar;
Repurposing consumables such as blotting paper, non-woven fabrics, and polyester film when they are no longer fit for their original purpose;
Using locally produced products whenever possible, to reduce carbon footprints;
Reusing packaging materials such as cardboard boxes, plastic wrap and wooden crates;
Using standard sizes of packaging and package designs that reduce waste;
These decisions are not always straightforward - for example, installing deionised or distilled water filters in laboratories reduces waste associated with purchasing bottled products, but increases energy consumption. Similarly, locally-made papers and boards may reduce inherent carbon miles but they may be made with pulp sourced from old growth forests.
Another dilemma is that many conservation-grade materials are chosen because they do not biodegrade. For example, when selecting a plastic with which to make storage enclosures, conservators prefer to use relatively long-lived plastics because they have better ageing properties - they are less likely to become yellow, leach plasticisers, or lose structural integrity and crumble (examples include polyethylene, polypropylene, and polyester). These plastics will also take longer to degrade in landfill.
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Conservation and restoration of cultural property
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Energy use
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Energy use
Many conservators and cultural organisations have sought to reduce the energy costs associated with controlling indoor storage and display environments (temperature, relative humidity, air filtration, and lighting levels) as well as those associated with the transport of cultural heritage items for exhibitions and loans.
In general, lowering the temperature reduces the rate at which damaging chemical reactions occur within materials. For example, storing cellulose acetate film at 10 °C instead of 21 °C is estimated to increase its usable life by over 100 years. Controlling the relative humidity of air helps to reduce hydrolysis reactions and minimises cracking, distortion and other physical changes in hygroscopic materials. Changes in temperature will also bring about changes in relative humidity. Therefore, the conservation profession has placed great importance on controlling indoor environments. Temperature and humidity can be controlled through passive means (e.g. insulation, building design) or active means (air conditioning). Active controls typically require much higher energy use. Energy use increases with specificity - e.g. in will require more energy to maintain a quantity of air to a narrow temperature range (20-22 °C) than to a broad range (18-25 °C). In the past, conservation recommendations have often called for very tight, inflexible temperature and relative humidity set points. In other cases, conservators have recommended strict environmental conditions for buildings that could not reasonably be expected to achieve them, due to the quality of build, local environmental conditions (e.g. recommending temperate conditions for a building located in the tropics) or the financial circumstances of the organisation. This has been an area of particular debate for cultural heritage organisations who lend and borrow cultural items to each other - often, the lender will specify strict environmental conditions as part of the loan agreement, which may be very expensive for the borrowing organisation to achieve, or impossible.
The energy costs associated with cold storage and digital storage are also gaining more attention. Cold storage is a very effective strategy to preserve at-risk collections such as cellulose nitrate and cellulose acetate film, which can deteriorate beyond use within decades at ambient conditions. Digital storage costs are rising for both born-digital cultural heritage (photographs, audiovisual, time-based media) and to store digital preservation and access copies of cultural heritage. Digital storage capacity is a major factor in the complexity of preserving digital heritage such as video games, social media, messaging services, and email.
Other areas where energy use can be reduced within conservation and restoration include:
Exhibition lighting - e.g. using lower-energy LED lighting systems and light sensors that switch lights on only when visitors are present;
Installation of green energy capture systems in cultural organisations, such as solar photovoltaic plates, wind energy systems, and heat pumps;
Improving the energy performance of cultural buildings by installing insulation, sealing gaps, reducing the number of windows and installing double-glazing:
Using microclimates to house small groups of climate-sensitive objects instead of seeking to control the environmental conditions of the whole building.
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Conservation and restoration of cultural property
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Country by country look
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Country by country look
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Conservation and restoration of cultural property
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United States
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United States
Heritage Preservation, in partnership with the Institute of Museum and Library Services, a U.S. federal agency, produced The Heritage Health Index. The results of this work was the report A Public Trust at Risk: The Heritage Health Index Report on the State of America's Collections, which was published in December 2005 and concluded that immediate action is needed to prevent the loss of 190 million artifacts that are in need of conservation treatment. The report made four recommendations:
Institutions must give priority to providing safe conditions for the collections they hold in trust.
Every collecting institution must develop an emergency plan to protect its collections and train staff to carry it out.
Every institution must assign responsibility for caring for collections to members of its staff.
Individuals at all levels of government and in the private sector must assume responsibility for providing the support that will allow these collections to survive.
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Conservation and restoration of cultural property
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United Kingdom
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United Kingdom
thumb|Conservation in Progress note, Victoria and Albert Museum (2014)
In October 2006, the Department for Culture, Media and Sport, a governmental department, authored a document: "Understanding the Future: Priorities for England's Museums". This document was based on several years of consultation aimed to lay out the government's priorities for museums in the 21st century.
The document listed the following as priorities for the next decade:
Museums will fulfil their potential as learning resources (pp 7–10).
Museums will be embedded into the delivery of education in every school in the country.
Understanding of the effectiveness of museum education will be improved further and best practice built into education programmes.
The value of museums' collections as a research resource will be well understood and better links built between the academic community and museums.
Museums will embrace their role in fostering, exploring, celebrating and questioning the identities of diverse communities (pp 11–14).
The sector needs to work with partners in academia and beyond to create an intellectual framework supporting museums' capacity to tackle issues of identity.
The museum sector must continue to develop improved practical techniques for engaging communities of all sorts.
Museums' collections will be more dynamic and better used (pp 15–18).
Government and the sector will find new ways to encourage museums to collect actively and strategically, especially the record of contemporary society.
The sector will develop new collaborative approaches to sharing and developing collections and related expertise.
Museums' workforce will be dynamic, highly skilled and representative (pp 17–22).
Museums' governing bodies and workforce will be representative of the communities they serve.
Find more varied ways for a broader range of skills to come into museums.
Improve continuing professional development.
Museums will work more closely with each other and partners outside the sector (pp 23–26).
A consistent evidence base of the contribution of all kinds of museums to the full range of public service agendas will be developed.
There will be deeper and longer lasting partnerships between the national museums and a broader range of regional partners.
Museums' international roles will be strengthened to improve museum programmes in this country and Britain's image, reputation and relationships abroad.
The conservation profession response to this report was on the whole less than favourable, the Institute of Conservation (ICON) published their response under the title "A Failure of Vision". It had the following to say:
Concluding:
Further to this the ICON website summary report lists the following specific recommendations:
A national survey to find out what the public want from museums, what motivates them to visit them and what makes for a rewarding visit.
A review of survey results and prioritisation of the various intrinsic, instrumental and institutional values to provide a clear basis for a 10-year strategy
HR consultants to be brought in from the commercial sector to review recruitment, career development and working practices in the national and regional museums.
A commitment to examine the potential for using Museum Accreditation as a more effective driver for improving recruitment, diversity, and career development across the sector.
DCMS to take full account of the eventual findings of the current Commons Select Committee enquiry into Care of Collections in the final version of this document
The adoption of those recommendations of the recent House of Lords inquiry into Science and Heritage which might affect the future of museums.
In November 2008, the UK-based think tank Demos published an influential pamphlet entitled It's a material world: caring for the public realm, in which they argue for integrating the public directly into efforts to conserve material culture, particularly that which is in the public, their argument, as stated on page 16, demonstrates their belief that society can benefit from conservation as a paradigm as well as a profession:
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Conservation and restoration of cultural property
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Training
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Training
Training in conservation of cultural heritage for many years took the form of an apprenticeship, whereby an apprentice slowly developed the necessary skills to undertake their job. For some specializations within conservation this is still the case. However, it is more common in the field of conservation today that the training required to become a practicing conservator comes from a recognized university course in conservation of cultural heritage.
The university can rarely provide all the necessary training in first hand experience that an apprenticeship can, and therefore in addition to graduate level training the profession also tends towards encouraging conservation students to spend time as an intern.
Conservation of cultural heritage is an interdisciplinary field as conservators have backgrounds in the fine arts, sciences (including chemistry, biology, and materials science), and closely related disciplines, such as art history, archaeology, and anthropology. They also have design, fabrication, artistic, and other special skills necessary for the practical application of that knowledge.
Within the various schools that teach conservation of cultural heritage, the approach differs according to the educational and vocational system within the country, and the focus of the school itself. This is acknowledged by the American Institute for Conservation who advise "Specific admission requirements differ and potential candidates are encouraged to contact the programs directly for details on prerequisites, application procedures, and program curriculum".
In France, training for heritage conservation is taught by four schools : , L'École supérieure des Beaux-Arts Tours, Angers, Le Mans, L'Université Paris 1 Panthéon-Sorbonne, Institut national du patrimoine.
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Conservation and restoration of cultural property
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Associations and professional organizations
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Associations and professional organizations
Societies devoted to the care of cultural heritage have been in existence around the world for many years. One early example is the founding in 1877 of the Society for the Protection of Ancient Buildings in Britain to protect the built heritage, this society continues to be active today.History of the SPAB . Retrieved on 2012-06-29. The 14th Dalai Lama and the Tibetan people work to preserve their cultural heritage with organizations including the Tibetan Institute of Performing Arts and an international network of eight Tibet Houses.
The built heritage was at the forefront of the growth of member based organizations in the United States. Preservation Virginia, founded in Richmond in 1889 as the Association for the Preservation of Virginia Antiquities, was the United States' first statewide historic preservation group.APVA Preservation Virginia . Apva.org. Retrieved on 2012-06-29.
Today, professional conservators join and take part in the activities of numerous conservation associations and professional organizations with the wider field, and within their area of specialization. In Europe, E.C.C.O. European Confederation of Conservator-Restorers Organisations was established in 1991 by 14 European Conservator-Restorers' Organisations. Currently representing close to 6.000 professionals within 23 countries and 26 members organisations, including one international body (IADA), E.C.C.O. embodies the field of preservation of cultural heritage, both movable and immovable.
These organizations exist to "support the conservation professionals who preserve our cultural heritage".About AIC – Overview. Conservation-us.org. Retrieved on 2012-06-29.
This involves upholding professional standards, promoting research and publications, providing educational opportunities, and fostering the exchange of knowledge among cultural conservators, allied professionals, and the public.
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Conservation and restoration of cultural property
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International cultural property documents
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International cultural property documents
Year Document Sponsor Text (English where available)1931Athens CharterInternational Congress of Architects and Technicians of Historic Monumentstext1931Carta Di AteneConferenza Internazionale di Atenetext (Italian)1932Carta Italiana del restauroConsiglio Superiore Per Le Antichità e Belle Artitext (Italian)1933Charter of AthensIV CIAMtext1956New Delhi RecommendationIX UNESCOtext, text1962Paris RecommendationXII UNESCOtext1964Venice CharterII International Congress of Architects and Technicians of Historic Monumentstext, text1964Paris RecommendationXIII UNESCOtext1967Norms of QuitoOAStext (Spanish), text1968Paris RecommendationXV UNESCOtext1972Paris ConventionXVII UNESCOtext1972Paris RecommendationXVII UNESCOtext1972Carta Italiana del Restaurotext (Italian)1972Stockholm DeclarationUNEPtext1974Santo Domingo Resolution, Dominican RepublicInteramerican Seminar on the Conservation and Restoration of the Architectural Heritage of the Colonial and Republican Periods – OAStext (Portuguese), text (Portuguese)1975Declaration of AmsterdamCongress on the European Architectural Heritagetext1975European Charter of the Architectural HeritageCouncil of Europetext1976Charter on Cultural Tourism, BrusselsInternational Seminar on Contemporary Tourism and Humanismtext1976Nairobi RecommendationXIX UNESCOtext1977Machu Picchu Chartertext (Portuguese), text (Portuguese), text (Spanish), ref (Spanish)1981Burra CharterICOMOStext1982Florence CharterICOMOS: Historic Gardenstext, text1982Nairobi DeclarationUNEPtext 1982Tlaxcala DeclarationICOMOStext1982México DeclarationWorld Conference on Cultural Policies – MONDIACULTtext, text1983Declaration of RomeICOMOStext1987Carta della conservazione e del restauro degli oggetti d'arte e di culturatext (Italian)1987Washington CharterICOMOStext, text1989Paris RecommendationXXV UNESCOtext1990Lausanne CharterICOMOS / ICAHMtext, text1994Nara DocumentUNESCO / ICCROM / ICOMOStext, text1995European RecommendationCouncil of Europe, Committee of Ministerstext (Rec(95)3E),
text (Rec(95)9E)1996Declaration of San AntonioICOMOStext1997Declaration of SofiaXI ICOMOS or XXIX UNESCOtext1997Carta de Mar del PlataMercosurtext (Portuguese), text (Portuguese), text (Spanish), text (Spanish)2000Cracow Chartertext (Italian)2002Declaration of Cartagena de Indias, ColômbiaConselho Andino, OAStext2003Paris RecommendationXXXII UNESCOtext2017Delhi DeclarationICOMOStext (English)
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Conservation and restoration of cultural property
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See also
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See also
Art discovery
Conservation and restoration of rail vehicles
The Georgian Group
Wikipedia:WikiProject Collections Care
International Day For Monuments and Sites
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Conservation and restoration of cultural property
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References
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References
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Conservation and restoration of cultural property
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Further reading
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Further reading
Copies of this volume are available for free pdf download from the Smithsonian's digital library by clicking on the included link.
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Conservation and restoration of cultural property
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External links
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External links
BCIN, the Bibliographic Database of the Conservation Information Network
CAMEO: Conservation and Art Materials Encyclopedia OnLine
Conservation OnLine (CoOL) Resources for Conservation Professionals
DOCAM — Documentation and Conservation of the Media Arts Heritage
ICOMOS Open Archive: EPrints on Cultural Heritage
Publications & Resources at the Getty Conservation Institute
Category:Art history
Category:Museology
Category:Cultural heritage
Category:Articles containing video clips
Category:Cultural heritage conservation
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Conservation and restoration of cultural property
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Table of Content
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short description, Definition, History and science, Key dates, Brief history, Conservation laboratories, Ethics, Practice, Preventive conservation, Interventive conservation and restoration, Example of an archaeological discovery and restoration of a mural painting, Examples of the restoration of an oil painting, Sustainable conservation, Choice of materials, Energy use, Country by country look, United States, United Kingdom, Training, Associations and professional organizations, International cultural property documents, See also, References, Further reading, External links
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Anton Chekhov
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Short description
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thumb|upright=.8|Portrait of Anton Chekhov by Isaac Levitan (1886)
Anton Pavlovich Chekhov (; ; 29 January 1860 – 15 July 1904) was a Russian playwright and short-story writer, widely considered to be one of the greatest writers of all time. His career as a playwright produced four classics, and his best short stories are held in high esteem by writers and critics. Along with Henrik Ibsen and August Strindberg, Chekhov is often referred to as one of the three seminal figures in the birth of early modernism in the theatre. Chekhov was a physician by profession. "Medicine is my lawful wife," he once said, "and literature is my mistress."
Chekhov renounced the theatre after the reception of The Seagull in 1896, but the play was revived to acclaim in 1898 by Konstantin Stanislavski's Moscow Art Theatre, which subsequently also produced Chekhov's Uncle Vanya and premiered his last two plays, Three Sisters and The Cherry Orchard. These four works present a challenge to the acting ensemble as well as to audiences, because in place of conventional action Chekhov offers a "theatre of mood" and a "submerged life in the text." The plays that Chekhov wrote were not complex, but easy to follow, and created a somewhat haunting atmosphere for the audience.
Chekhov began writing stories to earn money, but as his artistic ambition grew, he made formal innovations that influenced the evolution of the modern short story."Tchehov's breach with the classical tradition is the most significant event in modern literature," John Middleton Murry, in Athenaeum, 8 April 1922, cited in Bartlett's introduction to About Love. He made no apologies for the difficulties this posed to readers, insisting that the role of an artist was to ask questions, not to answer them.
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Anton Chekhov
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Biography
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Biography
thumb|left|Birth house of Anton Chekhov in Taganrog, Chekhova street, Russia
thumb|left|The Taganrog Boys Gymnasium in the late 19th century. The cross on top is no longer present.
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Anton Chekhov
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Childhood
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Childhood
Anton Pavlovich Chekhov was born on the feast day of St. Anthony the Great (17 January Old Style) 29 January 1860 in Taganrog, a commercial port city on the Sea of Azov – on Politseyskaya (Police) street, later renamed Chekhova street – in southern Russia. He was the third of six surviving children; he had two older brothers, Alexander and Nikolai, and three younger siblings, Ivan, Maria, and Mikhail. His father, Pavel Yegorovich Chekhov, the son of a former serf and his wife,: Egor Mikhailovich Chekhov and Efrosinia Emelianovna was from the village Olkhovatka (Voronezh Governorate) and ran a grocery store. He was a director of the parish choir, a devout Orthodox Christian, and a physically abusive father. Pavel Chekhov has been seen by some historians as the model for his son's many portraits of hypocrisy. Chekhov's mother, Yevgeniya (Morozova), was an excellent storyteller who entertained the children with tales of her travels all over Russia with her cloth-merchant father. "Our talents we got from our father," Chekhov recalled, "but our soul from our mother."From the biographical sketch, adapted from a memoir by Chekhov's brother Mihail, which prefaces Constance Garnett's translation of Chekhov's letters, 1920.
Young Chekhov attended the Greek School in Taganrog and The Taganrog Boys Gymnasium (since renamed the Chekhov Gymnasium). There he was held back for a year at fifteen for failing an examination in Ancient Greek.Bartlett, pp. 4–5. He sang at the Greek Orthodox monastery in Taganrog and in his father's choirs. In a letter of 1892, he used the word "suffering" to describe his childhood and recalled:
Later, in his adulthood, Chekhov criticized his brother Alexander's treatment of his wife and children by reminding him of their father Pavel's tyranny: "Let me ask you to recall that it was despotism and lying that ruined your mother's youth. Despotism and lying so mutilated our childhood that it's sickening and frightening to think about it. Remember the horror and disgust we felt in those times when Father threw a tantrum at dinner over too much salt in the soup and called Mother a fool."
In 1876, Chekhov's father Pavel was declared bankrupt after overextending his finances building a new house, having been cheated by a contractor named Mironov. To avoid debtor's prison he fled to Moscow, where his two eldest sons, Alexander and Nikolai, were attending university. The family lived in poverty in Moscow. Chekhov's mother was physically and emotionally broken by the experience.Letter to cousin Mihail, 10 May 1877. Letters of Anton Chekhov.
Chekhov was left behind to sell the family's possessions and finish his education. He remained in Taganrog for three more years, boarding with a man by the name of Selivanov who, like Lopakhin in The Cherry Orchard, had bailed out the family for the price of their house. Chekhov had to pay for his own education, which he managed by private tutoring, catching and selling goldfinches, and selling short sketches to the newspapers, among other jobs. He sent every ruble he could spare to his family in Moscow, along with humorous letters to cheer them up.
As a teenager Chekhov fell in love with the Taganrog Theatre. He attended the theatre on a regular basis and became enchanted and inspired by productions of vaudevilles, Italian operas and popular comedies.Chekhov and Taganrog: Taganrog Theatre:
During that time, Chekhov read widely and analytically, including the works of Cervantes, Turgenev, Goncharov, and Schopenhauer,Letter to brother Mihail, 1 July 1876. Letters of Anton Chekhov. and wrote a full-length comic drama, Fatherless, which his brother Alexander dismissed as "an inexcusable though innocent fabrication." Chekhov also experienced a series of love affairs, one with the wife of a teacher. In 1879, Chekhov completed his schooling in Taganrog and moved in with his family in Moscow, having gained admission to the medical school at I.M. Sechenov First Moscow State Medical University.
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Anton Chekhov
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Early writings
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Early writings
Chekhov then assumed responsibility for the whole family. To support them and to pay his tuition fees, he wrote daily short, humorous sketches and vignettes of contemporary Russian life, many under pseudonyms such as "Antosha Chekhonte" (Антоша Чехонте) and "Man Without Spleen" (Человек без селезенки). His prodigious output gradually earned him a reputation as a satirical chronicler of Russian street life, and by 1882 he was writing for Oskolki (Fragments), owned by Nikolai Leykin, one of the leading publishers of the time. Chekhov's tone at this stage was harsher than that familiar from his mature fiction."There is in these miniatures an arresting potion of cruelty ... The wonderfully compassionate Chekhov was yet to mature." "Vodka Miniatures, Belching and Angry Cats", George Steiner's review of The Undiscovered Chekhov in The Observer, 13 May 2001. Retrieved 16 February 2007.
thumb|right|Portrait of young Chekhov in country clothes
thumb|left|Anton Chekhov (left) with brother Nikolai in 1882
thumb|upright=.7|left|Anton Chekhov in 1880s
In 1884, Chekhov qualified as a physician, which he considered his principal profession though he made little money from it and treated the poor free of charge.
In 1884 and 1885, Chekhov found himself coughing blood, and in 1886 the attacks worsened, but he would not admit his tuberculosis to his family or his friends. He confessed to Leykin, "I am afraid to submit myself to be sounded by my colleagues."Letter to N.A.Leykin, 6 April 1886. Letters of Anton Chekhov. He continued writing for weekly periodicals, earning enough money to move the family into progressively better accommodations.
Early in 1886 he was invited to write for one of the most popular papers in St. Petersburg, Novoye Vremya (New Times), owned and edited by the millionaire magnate Alexey Suvorin, who paid a rate per line double Leykin's and allowed Chekhov three times the space. Suvorin was to become a lifelong friend, perhaps Chekhov's closest.: They only ever fell out once, when Chekhov objected to the anti-Semitic attacks in New Times against Dreyfus and Zola in 1898.In many ways, the right-wing Suvorin, whom Lenin later called "The running dog of the Tzar" (Payne, XXXV), was Chekhov's opposite; "Chekhov had to function like Suvorin's kidney, extracting the businessman's poisons."
Before long, Chekhov was attracting literary as well as popular attention. The sixty-four-year-old Dmitry Grigorovich, a celebrated Russian writer of the day, wrote to Chekhov after reading his short story "The Huntsman" thatThe Huntsman.. Retrieved 16 February 2007. "You have real talent, a talent that places you in the front rank among writers in the new generation." He went on to advise Chekhov to slow down, write less, and concentrate on literary quality.
Chekhov replied that the letter had struck him "like a thunderbolt" and confessed, "I have written my stories the way reporters write up their notes about fires—mechanically, half-consciously, caring nothing about either the reader or myself." The admission may have done Chekhov a disservice, since early manuscripts reveal that he often wrote with extreme care, continually revising. Grigorovich's advice nevertheless inspired a more serious, artistic ambition in the twenty-six-year-old. In 1888, with a little string-pulling by Grigorovich, the short story collection At Dusk (V Sumerkakh) won Chekhov the coveted Pushkin Prize "for the best literary production distinguished by high artistic worth."
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Anton Chekhov
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Turning points
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Turning points
thumb|Chekhov's family and friends in 1890: (top row, left to right) Ivan, Alexander, father; (second row) Mariya Korniyeeva, Lika Mizinova, Masha, Mother, Seryozha Kiselev; (bottom row) Misha, Anton
In 1887, exhausted from overwork and ill health, Chekhov took a trip to Ukraine, which reawakened him to the beauty of the steppe."There is a scent of the steppe and one hears the birds sing. I see my old friends the ravens flying over the steppe." Letter to sister Masha, 2 April 1887. Letters of Anton Chekhov. On his return, he began the novella-length short story "The Steppe", which he called "something rather odd and much too original", and which was eventually published in Severny Vestnik (The Northern Herald).Letter to Grigorovich, 12 January 1888. Quoted by . In a narrative that drifts with the thought processes of the characters, Chekhov evokes a chaise journey across the steppe through the eyes of a young boy sent to live away from home, and his companions, a priest and a merchant. "The Steppe" has been called a "dictionary of Chekhov's poetics", and it represented a significant advance for Chekhov, exhibiting much of the quality of his mature fiction and winning him publication in a literary journal rather than a newspaper."'The Steppe,' as Michael Finke suggests, is 'a sort of dictionary of Chekhov's poetics,' a kind of sample case of the concealed literary weapons Chekhov would deploy in his work to come." .
In autumn 1887, a theatre manager named Korsh commissioned Chekhov to write a play, the result being Ivanov, written in a fortnight and produced that November.From the biographical sketch, adapted from a memoir by Chekhov's brother Mikhail, which prefaces Constance Garnett's translation of Chekhov's letters, 1920. Though Chekhov found the experience "sickening" and painted a comic portrait of the chaotic production in a letter to his brother Alexander, the play was a hit and was praised, to Chekhov's bemusement, as a work of originality.Letter to brother Alexander, 20 November 1887. Letters of Anton Chekhov.
Although Chekhov did not fully realise it at the time, Chekhov's plays, such as The Seagull (written in 1895), Uncle Vanya (written in 1897), The Three Sisters (written in 1900), and The Cherry Orchard (written in 1903) served as a revolutionary backbone to what is common sense to the medium of acting to this day: an effort to recreate and express the realism of how people truly act and speak with each other. This realistic manifestation of the human condition may engender in audiences reflection upon what it means to be human.
This philosophy of approaching the art of acting has stood not only steadfast, but as the cornerstone of acting for much of the 20th century to this day. Mikhail Chekhov considered Ivanov a key moment in his brother's intellectual development and literary career. From this period comes an observation of Chekhov's that has become known as Chekhov's gun, a dramatic principle that requires that every element in a narrative be necessary and irreplaceable, and that everything else be removed.
The death of Chekhov's brother Nikolai from tuberculosis in 1889 influenced A Dreary Story, finished that September, about a man who confronts the end of a life that he realises has been without purpose. Mikhail Chekhov recorded his brother's depression and restlessness after Nikolai's death. Mikhail was researching prisons at that time as part of his law studies. Anton Chekhov, in a search for purpose in his own life, himself soon became obsessed with the issue of prison reform.
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Anton Chekhov
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Sakhalin
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Sakhalin
thumb|Anton Chekhov in 1893
In 1890, Chekhov undertook an arduous journey by train, horse-drawn carriage, and river steamer across Siberia to the Russian Far East and the katorga, or penal colony, on Sakhalin Island, north of Japan. He spent three months there interviewing thousands of convicts and settlers for a census. The letters Chekhov wrote during the two-and-a-half-month journey to Sakhalin are considered to be among his best. His remarks to his sister about Tomsk were to become notorious.
Chekhov witnessed much on Sakhalin that shocked and angered him, including floggings, embezzlement of supplies, and forced prostitution of women. He wrote, "There were times I felt that I saw before me the extreme limits of man's degradation." He was particularly moved by the plight of the children living in the penal colony with their parents. For example:
Chekhov later concluded that charity was not the answer, but that the government had a duty to finance humane treatment of the convicts. His findings were published in 1893 and 1894 as Ostrov Sakhalin (The Island of Sakhalin), a work of social science, not literature.: Such is the general critical view of the work, but Simmons calls it a "valuable and intensely human document." Chekhov found literary expression for the "Hell of Sakhalin" in his long short story "The Murder", the last section of which is set on Sakhalin, where the murderer Yakov loads coal in the night while longing for home. Chekhov's writing on Sakhalin, especially the traditions and habits of the Gilyak people, is the subject of a sustained meditation and analysis in Haruki Murakami's novel 1Q84.Murakami, Haruki. 1Q84. Alfred A. Knopf: New York, 2011. It is also the subject of a poem by the Nobel Prize winner Seamus Heaney, "Chekhov on Sakhalin" (collected in the volume Station Island).Heaney, Seamus. Station Island Farrar Straus Giroux: New York, 1985. Rebecca Gould has compared Chekhov's book on Sakhalin to Katherine Mansfield's Urewera Notebook (1907). In 2013, the Wellcome Trust-funded play 'A Russian Doctor', performed by Andrew Dawson and researched by Professor Jonathan Cole, explored Chekhov's experiences on Sakhalin Island.
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Anton Chekhov
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Melikhovo
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Melikhovo
thumb|Melikhovo, now a museum
Mikhail Chekhov, a member of the household at Melikhovo, described the extent of his brother's medical commitments:
Chekhov's expenditure on drugs was considerable, but the greatest cost was making journeys of several hours to visit the sick, which reduced his time for writing.From the biographical sketch, adapted from a memoir by Chekhov's brother Mihail, which prefaces Constance Garnett's translation of Chekhov's letters, 1920. However, Chekhov's work as a doctor enriched his writing by bringing him into intimate contact with all sections of Russian society: for example, he witnessed at first hand the peasants' unhealthy and cramped living conditions, which he recalled in his short story "Peasants". Chekhov visited the upper classes as well, recording in his notebook: "Aristocrats? The same ugly bodies and physical uncleanliness, the same toothless old age and disgusting death, as with market-women." In 1893/1894 he worked as a Zemstvo doctor in Zvenigorod, which has numerous sanatoriums and rest homes. A local hospital is named after him.
In 1894, Chekhov began writing his play The Seagull in a lodge he had built in the orchard at Melikhovo. In the two years since he had moved to the estate, he had refurbished the house, taken up agriculture and horticulture, tended the orchard and the pond, and planted many trees, which, according to Mikhail, he "looked after ... as though they were his children. Like Colonel Vershinin in his Three Sisters, as he looked at them he dreamed of what they would be like in three or four hundred years."
The first night of The Seagull, at the Alexandrinsky Theatre in St. Petersburg on 17 October 1896, was a fiasco, as the play was booed by the audience, stinging Chekhov into renouncing the theatre. But the play so impressed the theatre director Vladimir Nemirovich-Danchenko that he convinced his colleague Konstantin Stanislavski to direct a new production for the innovative Moscow Art Theatre in 1898.Benedetti, Stanislavski: An Introduction, 25. Stanislavski's attention to psychological realism and ensemble playing coaxed the buried subtleties from the text, and restored Chekhov's interest in playwriting.Chekhov and the Art Theatre, in Stanislavski's words, were united in a common desire "to achieve artistic simplicity and truth on the stage." The Art Theatre commissioned more plays from Chekhov and the following year staged Uncle Vanya, which Chekhov had completed in 1896.: Rayfield draws from his critical study Chekhov's "Uncle Vanya" and the "Wood Demon" (1995), which anatomised the evolution of the Wood Demon into Uncle Vanya—"one of Chekhov's most furtive achievements." In the last decades of his life he became an atheist.
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Anton Chekhov
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Yalta
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Yalta
In March 1897, Chekhov suffered a major haemorrhage of the lungs while on a visit to Moscow. With great difficulty he was persuaded to enter a clinic, where doctors diagnosed tuberculosis on the upper part of his lungs and ordered a change in his manner of life.
thumb|left|Chekhov with Leo Tolstoy at Yalta, 1900
After his father's death in 1898, Chekhov bought a plot of land on the outskirts of Yalta and built a villa (The White Dacha), into which he moved with his mother and sister the following year. Though he planted trees and flowers, kept dogs and tame cranes, and received guests such as Leo Tolstoy and Maxim Gorky, Chekhov was always relieved to leave his "hot Siberia" for Moscow or travels abroad. He vowed to move to Taganrog as soon as a water supply was installed there.Olga Knipper, "Memoir", in Bartlett, 2. In Yalta he completed two more plays for the Art Theatre, composing with greater difficulty than in the days when he "wrote serenely, the way I eat pancakes now". He took a year each over Three Sisters and The Cherry Orchard.
On 25 May 1901, Chekhov married Olga Knipper quietly, owing to his horror of weddings. She was a former protégée and sometime lover of Vladimir Nemirovich-Danchenko whom he had first met at rehearsals for The Seagull."I have a horror of weddings, the congratulations and the champagne, standing around, glass in hand with an endless grin on your face." Letter to Olga Knipper, 19 April 1901. Up to that point, Chekhov, known as "Russia's most elusive literary bachelor",Harvey Pitcher in Chekhov's Leading Lady, quoted in . had preferred passing liaisons and visits to brothels over commitment."Chekhov had the temperament of a philanderer. Sexually, he preferred brothels or swift liaisons." He had once written to Suvorin:
thumb|upright=.7|Chekhov and Olga, 1901, on their honeymoon
The letter proved prophetic of Chekhov's marital arrangements with Olga: he lived largely at Yalta, she in Moscow, pursuing her acting career. In 1902, Olga suffered a miscarriage; and Donald Rayfield has offered evidence, based on the couple's letters, that conception occurred when Chekhov and Olga were apart, although other Russian scholars have rejected that claim.There was certainly tension between the couple after the miscarriage, though , and , put this down to Chekhov's mother and sister blaming the miscarriage on Olga's late-night socialising with her actor friends. The literary legacy of this long-distance marriage is a correspondence that preserves gems of theatre history, including shared complaints about Stanislavski's directing methods and Chekhov's advice to Olga about performing in his plays.
In Yalta, Chekhov wrote one of his most famous stories, "The Lady with the Dog" (also translated from the Russian as "Lady with Lapdog"),Greenberg, Yael. "The Presentation of the Unconscious in Chekhov's Lady With Lapdog." Modern Language Review 86.1 (1991): 126–130. Academic Search Premier. Web. 3 November 2011. which depicts what at first seems a casual liaison between a cynical married man and an unhappy married woman who meet while holidaying in Yalta. Neither expects anything lasting from the encounter. Unexpectedly though, they gradually fall deeply in love and end up risking scandal and the security of their family lives. The story masterfully captures their feelings for each other, the inner transformation undergone by the disillusioned male protagonist as a result of falling deeply in love, and their inability to resolve the matter by either letting go of their families or of each other."Overview: 'The Lady with the Dog'." Characters in 20th-Century Literature. Laurie Lanzen Harris. Detroit: Gale Research, 1990. Literature Resource Center. Web. 3 November 2011.
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Anton Chekhov
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Death
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Death
In May 1903, Chekhov visited Moscow; the prominent lawyer Vasily Maklakov visited him almost every day. Maklakov signed Chekhov's will. By May 1904, Chekhov was terminally ill with tuberculosis. Mikhail Chekhov recalled that "everyone who saw him secretly thought the end was not far off, but the nearer [he] was to the end, the less he seemed to realise it". On 3 June, he set off with Olga for the German spa town of Badenweiler in the Black Forest in Germany, from where he wrote outwardly jovial letters to his sister Masha, describing the food and surroundings, and assuring her and his mother that he was getting better. In his last letter, he complained about the way German women dressed.Letter to sister Masha, 28 June 1904. Letters of Anton Chekhov. Chekhov died on 15 July 1904 at the age of 44 after a long fight with tuberculosis, the same disease that killed his brother.
Chekhov's death has become one of "the great set pieces of literary history"retold, embroidered, and fictionalized many times since, notably in the 1987 short story "Errand" by Raymond Carver. In 1908, Olga wrote this account of her husband's last moments:
Chekhov's body was transported to Moscow in a refrigerated railway-car meant for oysters, a detail that offended Gorky."Banality revenged itself upon him by a nasty prank, for it saw that his corpse, the corpse of a poet, was put into a railway truck 'For the Conveyance of Oysters'." Maxim Gorky in Reminiscences of Anton Chekhov.. Retrieved 16 February 2007. Some of the thousands of mourners followed the funeral procession of a General Keller by mistake, to the accompaniment of a military band.Chekhov's Funeral. M. Marcus.The Antioch Review, 1995 Chekhov was buried next to his father at the Novodevichy Cemetery.; Alexander Kuprin in Reminiscences of Anton Chekhov. Retrieved 16 February 2007.
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Anton Chekhov
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Legacy
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Legacy
thumb|Anton Chekhov museum in Alexandrovsk-Sakhalinsky, Russia. It is the house where he stayed in Sakhalin during 1890.
A few months before he died, Chekhov told the writer Ivan Bunin that he thought people might go on reading his writings for seven years. "Why seven?", asked Bunin. "Well, seven and a half", Chekhov replied. "That's not bad. I've got six years to live."
Chekhov's posthumous reputation greatly exceeded his expectations. The ovations for the play The Cherry Orchard in the year of his death served to demonstrate the Russian public's acclaim for the writer, which placed him second in literary celebrity only to Tolstoy, who outlived him by six years. Tolstoy was an early admirer of Chekhov's short stories and had a series that he deemed "first quality" and "second quality" bound into a book. In the first category were: Children, The Chorus Girl, A Play, Home, Misery, The Runaway, In Court, Vanka, Ladies, A Malefactor, The Boys, Darkness, Sleepy, The Helpmate, and The Darling; in the second: A Transgression, Sorrow, The Witch, Verochka, In a Strange Land, The Cook's Wedding, A Tedious Business, An Upheaval, Oh! The Public!, The Mask, A Woman's Luck, Nerves, The Wedding, A Defenceless Creature, and Peasant Wives.
Chekhov's work also found praise from several of Russia's most influential radical political thinkers. If anyone doubted the gloom and miserable poverty of Russia in the 1880s, the anarchist theorist Peter Kropotkin responded, "read only Chekhov's novels!" Raymond Tallis further recounts that Vladimir Lenin believed his reading of the short story Ward No. 6 "made him a revolutionary". Upon finishing the story, Lenin is said to have remarked: "I absolutely had the feeling that I was shut up in Ward 6 myself!"
In Chekhov's lifetime, British and Irish critics generally did not find his work pleasing; E. J. Dillon thought "the effect on the reader of Chekhov's tales was repulsion at the gallery of human waste represented by his fickle, spineless, drifting people" and R. E. C. Long said "Chekhov's characters were repugnant, and that Chekhov revelled in stripping the last rags of dignity from the human soul". After his death, Chekhov was reappraised. Constance Garnett's translations won him an English-language readership and the admiration of writers such as James Joyce, Virginia Woolf, and Katherine Mansfield, whose story "The Child Who Was Tired" is similar to Chekhov's "Sleepy". The Russian critic D. S. Mirsky, who lived in England, explained Chekhov's popularity in that country by his "unusually complete rejection of what we may call the heroic values". In Russia itself, Chekhov's drama fell out of fashion after the revolution, but it was later incorporated into the Soviet canon. The character of Lopakhin, for example, was reinvented as a hero of the new order, rising from a modest background so as eventually to possess the gentry's estates."They won't allow a play which is seen to lament the lost estates of the gentry." Letter of Vladimir Nemirovich-Danchenko, quoted by Anatoly Smeliansky in "Chekhov at the Moscow Art Theatre", from The Cambridge Companion to Chekhov, 31–32.
thumb|upright=.7|Osip Braz, Anton Chekhov, 1898, oil on canvas; Tretyakov Gallery, Moscow
Despite Chekhov's reputation as a playwright, William Boyd asserts that his short stories represent the greater achievement."The plays lack the seamless authority of the fiction: there are great characters, wonderful scenes, tremendous passages, moments of acute melancholy and sagacity, but the parts appear greater than the whole." A Chekhov Lexicon, by William Boyd, The Guardian, 3 July 2004. Retrieved 16 February 2007. Raymond Carver, who wrote the short story "Errand" about Chekhov's death, believed that Chekhov was the greatest of all short story writers:
According to literary critic Daniel S. Burt, Chekhov was one of the greatest and most influential writers of all time.
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Anton Chekhov
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Style
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Style
One of the first non-Russians to praise Chekhov's plays was George Bernard Shaw, who subtitled his Heartbreak House "A Fantasia in the Russian Manner on English Themes", and pointed out similarities between the predicament of the British landed class and that of their Russian counterparts as depicted by Chekhov: "the same nice people, the same utter futility".Anna Obraztsova in "Bernard Shaw's Dialogue with Chekhov", from Miles, 43–44.
Ernest Hemingway, another writer influenced by Chekhov, was more grudging: "Chekhov wrote about six good stories. But he was an amateur writer."Letter from Ernest Hemingway to Archibald MacLeish, 1925 (from Selected Letters, p. 179), in Ernest Hemingway on Writing, Ed Larry W. Phillips, Touchstone, (1984) 1999, , 101. Comparing Chekhov to Tolstoy, Vladimir Nabokov wrote, "I do love Chekhov dearly. I fail, however, to rationalize my feeling for him: I can easily do so in regard to the greater artist, Tolstoy, with the flash of this or that unforgettable passage […], but when I imagine Chekhov with the same detachment all I can make out is a medley of dreadful prosaisms, ready-made epithets, repetitions, doctors, unconvincing vamps, and so forth; yet it is his works which I would take on a trip to another planet."Wikiquote quotes about Chekhov Nabokov called "The Lady with the Dog" "one of the greatest stories ever written" in its depiction of a problematic relationship, and described Chekhov as writing "the way one person relates to another the most important things in his life, slowly and yet without a break, in a slightly subdued voice".From Vladimir Nabokov's Lectures on Russian Literature, quoted by Francine Prose in Learning from Chekhov, 231.
For the writer William Boyd, Chekhov's historical accomplishment was to abandon what William Gerhardie called the "event plot" for something more "blurred, interrupted, mauled or otherwise tampered with by life"."For the first time in literature the fluidity and randomness of life was made the form of the fiction. Before Chekhov, the event-plot drove all fictions." William Boyd, referring to the novelist William Gerhardie's analysis in Anton Chekhov: A Critical Study, 1923. "A Chekhov Lexicon" by William Boyd, The Guardian, 3 July 2004. Retrieved 16 February 2007.
Virginia Woolf mused on the unique quality of a Chekhov story in The Common Reader (1925):
Michael Goldman has said of the elusive quality of Chekhov's comedies: "Having learned that Chekhov is comic ... Chekhov is comic in a very special, paradoxical way. His plays depend, as comedy does, on the vitality of the actors to make pleasurable what would otherwise be painfully awkward—inappropriate speeches, missed connections, faux pas, stumbles, childishness—but as part of a deeper pathos; the stumbles are not pratfalls but an energized, graceful dissolution of purpose."Michael Goldman, The Actor's Freedom: Towards a Theory of Drama, p72.
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Anton Chekhov
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Influence on dramatic arts
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Influence on dramatic arts
In the United States, Chekhov's reputation began its rise slightly later, partly through the influence of Stanislavski's system of acting, with its notion of subtext: "Chekhov often expressed his thought not in speeches", wrote Stanislavski, "but in pauses or between the lines or in replies consisting of a single word ... the characters often feel and think things not expressed in the lines they speak."Reynolds, Elizabeth (ed), Stanislavski's Legacy, Theatre Arts Books, 1987, , 81, 83."It was Chekhov who first deliberately wrote dialogue in which the mainstream of emotional action ran underneath the surface. It was he who articulated the notion that human beings hardly ever speak in explicit terms among each other about their deepest emotions, that the great, tragic, climactic moments are often happening beneath outwardly trivial conversation." Martin Esslin, from Text and Subtext in Shavian Drama, in 1922: Shaw and the last Hundred Years, ed. Bernard. F. Dukore, Penn State Press, 1994, , 200. The Group Theatre, in particular, developed the subtextual approach to drama, influencing generations of American playwrights, screenwriters, and actors, including Clifford Odets, Elia Kazan and, in particular, Lee Strasberg. In turn, Strasberg's Actors Studio and the "Method" acting approach influenced many actors, including Marlon Brando and Robert De Niro, though by then the Chekhov tradition may have been distorted by a preoccupation with realism. In 1981, the playwright Tennessee Williams adapted The Seagull as The Notebook of Trigorin. One of Anton's nephews, Michael Chekhov, would also contribute heavily to modern theatre, particularly through his unique acting methods which developed Stanislavski's ideas further.
Alan Twigg, the chief editor and publisher of the Canadian book review magazine B.C. BookWorld wrote:
Chekhov has also influenced the work of Japanese playwrights including Shimizu Kunio, Yōji Sakate, and Ai Nagai. Critics have noted similarities in how Chekhov and Shimizu use a mixture of light humour as well as an intense depictions of longing. Sakate adapted several of Chekhov's plays and transformed them in the general style of nō. Nagai also adapted Chekhov's plays, including Three Sisters, and transformed his dramatic style into Nagai's style of satirical realism while emphasising the social issues depicted in the play.
Chekhov's works have been adapted for the screen, including Sidney Lumet's Sea Gull and Louis Malle's Vanya on 42nd Street. Laurence Olivier's final effort as a film director was a 1970 adaptation of Three Sisters in which he also played a supporting role. His work has also served as inspiration or been referenced in numerous films. In Andrei Tarkovsky's 1975 film The Mirror, characters discuss his short story "Ward No. 6". Woody Allen has been influenced by Chekhov and references to his works are present in many of his films including Love and Death (1975), Interiors (1978) and Hannah and Her Sisters (1986). Plays by Chekhov are also referenced in François Truffaut's 1980 drama film The Last Metro, which is set in a theatre. The Cherry Orchard has a role in the comedy film Henry's Crime (2011). A portion of a stage production of Three Sisters appears in the 2014 drama film Still Alice. The 2022 Foreign Language Oscar winner, Drive My Car, is centered on a production of Uncle Vanya.
Several of Chekhov's short stories were adapted as episodes of the 1986 Indian anthology television series Katha Sagar. Another Indian television series titled Chekhov Ki Duniya aired on DD National in the 1990s, adapting different works of Chekhov.
Nuri Bilge Ceylan's Palme d'Or winner Winter Sleep was adapted from the short story "The Wife" by Anton Chekhov.
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Anton Chekhov
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Publications
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Publications
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Anton Chekhov
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See also
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See also
Chekhov's gun
Chekhov Library
Chekhov Monument in Rostov-on-Don
Ann Dunnigan, English-language translator
Jean-Claude van Itallie, English-language translator
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Anton Chekhov
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Explanatory notes
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Explanatory notes
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Anton Chekhov
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Citations
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Citations
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Anton Chekhov
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General and cited sources
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General and cited sources
Benedetti, Jean, Stanislavski: An Introduction, Methuen Drama, 1989 edition,
Borny, Geoffrey, Interpreting Chekhov, ANU Press, 2006, , free download
Chekhov, Anton, The Undiscovered Chekhov: Fifty New Stories, translated by Peter Constantine, Duck Editions, 2001,
ebooks also available at
Chekhov, Anton, Easter Week, translated by Michael Henry Heim, engravings by Barry Moser, Shackman Press, 2010
Chekhov, Anton, Letters of Anton Chekhov to His Family and Friends with Biographical Sketch, translated by Constance Garnett, Macmillan, 1920. Full text at Gutenberg.. Retrieved 16 February 2007.
Chekhov, Anton, Note-Book of Anton Chekhov, translated by S. S. Koteliansky and Leonard Woolf, B.W. Huebsch, 1921. Full text at Gutenberg.. Retrieved 16 February 2007.
Chekhov, Anton, The Other Chekhov, edited by Okla Elliott and Kyle Minor, with story introductions by Pinckney Benedict, Fred Chappell, Christopher Coake, Paul Crenshaw, Dorothy Gambrell, Steven Gillis, Michelle Herman, Jeff Parker, Benjamin Percy, and David R. Slavitt. New American Press, 2008 edition,
Chekhov, Anton, Seven Short Novels, translated by Barbara Makanowitzky, W. W. Norton & Company, 2003 edition,
Clyman, T. W. (Ed.). A Chekhov companion. Westport, Ct: Greenwood Press, (1985).
Finke, Michael C., Chekhov's 'Steppe': A Metapoetic Journey, an essay in Anton Chekhov Rediscovered, ed Savely Senderovich and Munir Sendich, Michigan Russian Language Journal, 1988,
Finke, Michael C., Seeing Chekhov: Life and Art, Cornell UP, 2005,
Gerhardie, William, Anton Chekhov, Macdonald, (1923) 1974 edition,
Gorky, Maksim, Alexander Kuprin, and I.A. Bunin, Reminiscences of Anton Chekhov, translated by S. S. Koteliansky and Leonard Woolf, B.W.Huebsch, 1921. Read at eldritchpress.. Retrieved 16 February 2007.
Gottlieb, Vera, and Paul Allain (eds), The Cambridge Companion to Chekhov, Cambridge University Press, 2000,
Jackson, Robert Louis, Dostoevsky in Chekhov's Garden of Eden – 'Because of Little Apples', in Dialogues with Dostoevsky, Stanford University Press, 1993,
Klawans, Harold L., Chekhov's Lie, 1997, . About the challenges of combining writing with the medical life.
Nabokov, Vladimir, Anton Chekhov, in Lectures on Russian Literature, Harvest/HBJ Books, [1981] 2002 edition, .
Pitcher, Harvey, Chekhov's Leading Lady: Portrait of the Actress Olga Knipper, J Murray, 1979,
Republished in 2012 as an ebook:
Prose, Francine, Learning from Chekhov, in Writers on Writing, ed. Robert Pack and Jay Parini, UPNE, 1991,
Sekirin, Peter. "Memories of Chekhov: Accounts of the Writer from His Family, Friends and Contemporaries," MacFarland Publishers, 2011,
Speirs, L. Tolstoy and Chekhov. Cambridge, England: University Press, (1971),
Stanislavski, Constantin, My Life in Art, Methuen Drama, 1980 edition,
Troyat, Henri, Chekhov, London: Macmillan, 1987,
Zeiger, Arthur, The Plays of Anton Chekhov, Claxton House, Inc., New York, NY, 1945.
Tufarulo, G, M., La Luna è morta e lo specchio infranto. Miti letterari del Novecento, vol.1 – G. Laterza, Bari, 2009– .
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Anton Chekhov
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External links
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External links
Biographical
Biography at The Literature Network
"Chekhov's Legacy" by Cornel West at NPR, 2004
The International competition of philological, culture and film studies works dedicated to Anton Chekhov's life and creative work
Documentary
2010: Tschechow lieben (Tschechow and Women) – Director: Marina Rumjanzewa – Language: German
Works
. All Constance Garnett's translations of the short stories and letters are available, plus the edition of the Note-book translated by S. S. Koteliansky and Leonard Woolf – see the "References" section for print publication details of all of these. Site also has translations of all the plays.
201 Stories by Anton Chekhov, translated by Constance Garnett presented in chronological order of Russian publication with annotations.
Антон Павлович Чехов. Указатель Texts of Chekhov's works in the original Russian, listed in chronological order, and also alphabetically by title. Retrieved June 2013.
Антон Павлович Чехов Texts of Chekhov's works in the original Russian. Retrieved 16 February 2007.
Category:1860 births
Category:1904 deaths
Category:19th-century diarists from the Russian Empire
Category:19th-century dramatists and playwrights from the Russian Empire
Category:19th-century non-fiction writers from the Russian Empire
Category:19th-century physicians from the Russian Empire
Category:19th-century short story writers from the Russian Empire
Category:20th-century anarchists
Category:20th-century deaths from tuberculosis
Category:20th-century Russian dramatists and playwrights
Category:20th-century Russian physicians
Category:20th-century Russian short story writers
Category:Burials at Novodevichy Cemetery
Category:Comedy writers
Category:Dramaturges
Category:Ecofeminists
Category:Male writers from the Russian Empire
Category:Modernist theatre
Category:Moscow Art Theatre
Category:Moscow State University alumni
Category:Novelists from the Russian Empire
Category:People from Yekaterinoslav Governorate
Category:Philanthropists from the Russian Empire
Category:Positivists
Category:Pushkin Prize winners
Category:Russian-language writers
Category:Russian atheists
Category:Russian anarchists
Category:Russian communists
Category:Russian environmentalists
Category:Russian feminists
Category:Russian male dramatists and playwrights
Category:Russian male novelists
Category:Russian Marxists
Category:Russian medical writers
Category:Russian opinion journalists
Category:Russian psychological fiction writers
Category:Russian socialists
Category:Tuberculosis deaths in Germany
Category:Writers from Taganrog
Category:Wikipedia articles containing unlinked shortened footnotes
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Anton Chekhov
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Table of Content
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Short description, Biography, Childhood, Early writings, Turning points, Sakhalin, Melikhovo, Yalta, Death, Legacy, Style, Influence on dramatic arts, Publications, See also, Explanatory notes, Citations, General and cited sources, External links
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Action Against Hunger
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Short description
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Action Against Hunger () is a global humanitarian organization which originated in France and is committed to ending world hunger. The organization helps malnourished children and provides communities with access to safe water and sustainable solutions to hunger.
Action Against Hunger worked in 56 countries around the world with more than 8,990 employees helping 28 million people in need.ActionAgainstHunger_GlobalPerformanceReport_2020.pdf
Action Against Hunger was established in 1979 by a group of French doctors, scientists, and writers. Nobel Prize-winning physicist Alfred Kastler served as the organization's first chairman. Currently, Mumbai-based businessman and philanthropist Ashwini Kakkar serves as International President of Action Against Hunger network.
The group initially provided assistance to Afghan refugees in Pakistan, famine-stricken Ugandan communities, and Cambodian refugees in Thailand. It expanded to address additional humanitarian concerns in Africa, the Middle East, Southeast Asia, the Balkans, and elsewhere during the 1980s and 1990s. Action Against Hunger's Scientific Committee pioneered the therapeutic milk formula (F100), now used by all major humanitarian aid organizations to treat acute malnutrition. Early results showed that treatment with F100 has the capacity to reduce the mortality rate of severely malnourished children to below 5%, with a median hospital fatality rate quoted of 23.5%. A few years later, the therapeutic milk was repackaged as ready-to-use therapeutic foods (RUTFs), a peanut-based paste packaged like a power bar. These bars allow for the treatment of malnutrition at home and do not require any preparation or refrigeration.
The international network currently has headquarters in eight countries – France, Germany, Spain, the United States, Canada, Italy, India, and the UK. Its four main areas of work include nutrition, food security, water and sanitation, and advocacy.
The integrated approaches with various sectors of intervention are:
Nutrition and Health
Water, Sanitation and Hygiene
Food Security & Livelihoods
Emergency Response
In 2022, Action Against Hunger USA is leading a USAID-funded project to address health and nutrition challenges associated with policy, advocacy, financing, and governance in communities around the world, and will work in partnership with leading organizations such as Pathfinder International, Amref Health Africa, Global Communities, Humanity & Inclusion, Kupenda for the Children, and Results for Development.
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Action Against Hunger
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Restaurants against hunger
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Restaurants against hunger
Action Against Hunger partners with leaders from the food and beverage industry to bring attention to global hunger. Each year, several campaigns are run by the network to raise funds and support the organisation's programs : Restaurants Against Hunger and Love Food Give Food.
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Action Against Hunger
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Countries of intervention
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Countries of intervention
In 2022, Action Against Hunger International Network is present in 56 countries:
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Action Against Hunger
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Africa
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Africa
Burkina Faso, Burundi, Cameroon, Ivory Coast, Ethiopia, Kenya, Liberia, Malawi, Madagascar, Mali, Mauritania, Niger, Nigeria, Uganda, Central African Republic, Democratic Republic of the Congo, Senegal, Sierra Leone, Somalia, South Sudan, Sudan, Tanzania, Chad, Zimbabwe, Zambia
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Action Against Hunger
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Asia
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Asia
Bangladesh, Myanmar, Cambodia, India, Indonesia, Nepal, Pakistan, Philippines, South Caucasus
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Action Against Hunger
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Caribbean
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Caribbean
Haïti
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Action Against Hunger
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Europe
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Europe
Turkey, Ukraine, Moldova, Romania, Poland
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Action Against Hunger
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Middle East
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Middle East
Afghanistan, Lebanon, Syria, Palestinian Occupied Territories, Yemen, Jordan, Iraq
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Action Against Hunger
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Latin America
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Latin America
Colombia, Guatemala, Nicaragua, Paraguay, Peru, Honduras, Venezuela
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Action Against Hunger
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Action Against Hunger international network
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Action Against Hunger international network
Since 1995 Action Against Hunger developed an international network to have a bigger global impact.
The Network has headquarters around the world: France, Germany, Spain, the United Kingdom, the United States, Canada, India, and Italy.
Action Against Hunger has also a West Africa Regional Office (WARO) located in Dakar, a Horn and Eastern Africa Regional Office in Nairobi, and five logistic platforms (Lyon, Paris, Barcelona, Dubai, Panama).
This network increases the human and financial capacities and enables specialisation per headquarter.
Action Against Hunger in France, Spain and the USA are the operational headquarters. They manage the interventions directly on the field. In order to maximize efficiency and coherence, these three operational headquarters work under the principle of one headquarter per country of intervention.
Action Against Hunger UK focuses on research, monitoring and evaluation, notably with Hunger Watch. The UK headquarters also plays an intermediary role with DFID.
Action Against Hunger Canada raises public and private funds in North America and plays an increasing role on the national level.
Action Against Hunger / Azione contro la Fame Italia raises private funds and promotes important campaigns in order to sensitize the Italian public opinion on hunger and malnutrition.
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Action Against Hunger
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See also
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See also
2006 Trincomalee massacre of NGO workers
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Action Against Hunger
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References
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References
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Action Against Hunger
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Further reading
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Further reading
Michelle Jurkovich. 2020. Feeding the Hungry: Advocacy and Blame in the Global Fight against Hunger. Cornell University Press.
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Action Against Hunger
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External links
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External links
Action Against Hunger US website
Action Against Hunger UK website
Action Contre la Faim France website
Acción Contra el Hambre Spain website
Action Contre la Faim Canada website
Aktion gegen den Hunger Germany website
Azione contro la Fame Italy website
Category:Development charities based in France
Category:Hunger relief organizations
Category:International charities
Category:Organizations based in Paris
Category:Organizations established in 1979
Category:1979 establishments in France
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Action Against Hunger
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Table of Content
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Short description, Restaurants against hunger, Countries of intervention, Africa, Asia, Caribbean, Europe, Middle East, Latin America, Action Against Hunger international network, See also, References, Further reading, External links
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AW
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wiktionary
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A&W, AW, Aw, aW or aw may refer to:
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AW
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Companies
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Companies
A&W Restaurants
A&W Root Beer
A&W (Canada)
Addison-Wesley, publishers
Africa World Airlines, IATA code
Prefix for helicopters made by AgustaWestland
Alienware
Allied Waste Industries, Inc, stock symbol on NYSE
Armstrong Whitworth, a British manufacturing company
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AW
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Media and entertainment
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Media and entertainment
Accel World, a Japanese light novel series
Active Worlds, a 3D virtual reality platform
Another World (TV series), an American soap opera
Athletics Weekly, a monthly track and field magazine published in the United Kingdom
Aviation Week, magazine
Call of Duty: Advanced Warfare, an action video game
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AW
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People
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People
A. H. Weiler (1908 – 2002), The New York Times film critic whose early reviews were signed with his initials A. W.
A. W. (poet), anonymous 16th century poet
Abraham Washington (A. W.), American professional wrestler and wrestling commentator
Alan Walker (born 1997), English-Norwegian music producer and DJ
Aw (father), honorific title in the Harari and Somali languages
Aw (surname), a Cantonese surname
John-Allison Weiss, an American singer-songwriter formerly known as A. W.
Andy Warhol, a leading figure in the pop art movement.
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AW
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Places
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Places
Ahrweiler (district), Germany, vehicle registration code
Aruba (ISO 3166-1 2-letter country code AW)
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AW
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Science and technology
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Science and technology
.aw, the internet top level domain country code for Aruba
Airwatt, a unit of the effectiveness of vacuum cleaners
Aw, categorization for tropical savanna climate in the Köppen classification system
AW, in German email subject line, equivalent to Re:
aw, or attowatt, an SI unit of power
aw, or water activity, the relative availability of water in a substance
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AW
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Other uses
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Other uses
Agencja Wywiadu, the Polish foreign intelligence service
Ahnapee and Western Railway, A&W
Arctic Warfare, a sniper rifle
Anthony Wayne Local School District, an American school district in Ohio
Aviation Warfare Systems Operator, a rating in the United States Navy
Aw, a digraph in Latin-script
A US Navy hull classification symbol: Distilling ship (AW)
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AW
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See also
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See also
Av
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AW
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Table of Content
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wiktionary, Companies, Media and entertainment, People, Places, Science and technology, Other uses, See also
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Apoptosis
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Short description
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Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, DNA fragmentation, and mRNA decay. The average adult human loses 50 to 70 billion cells each day due to apoptosis. For the average human child between 8 and 14 years old, each day the approximate loss is 20 to 30 billion cells.
In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo occurs because cells between the digits undergo a form of apoptosis that is genetically determined. Unlike necrosis, apoptosis produces cell fragments called apoptotic bodies that phagocytes are able to engulf and remove before the contents of the cell can spill out onto surrounding cells and cause damage to them.
Because apoptosis cannot stop once it has begun, it is a highly regulated process. Apoptosis can be initiated through one of two pathways. In the intrinsic pathway the cell kills itself because it senses cell stress, while in the extrinsic pathway the cell kills itself because of signals from other cells. Weak external signals may also activate the intrinsic pathway of apoptosis. Both pathways induce cell death by activating caspases, which are proteases, or enzymes that degrade proteins. The two pathways both activate initiator caspases, which then activate executioner caspases, which then kill the cell by degrading proteins indiscriminately.
In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in a wide variety of diseases. Excessive apoptosis causes atrophy, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer. Some factors like Fas receptors and caspases promote apoptosis, while some members of the Bcl-2 family of proteins inhibit apoptosis.
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Apoptosis
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Discovery and etymology
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Discovery and etymology
German scientist Carl Vogt was first to describe the principle of apoptosis in 1842. In 1885, anatomist Walther Flemming delivered a more precise description of the process of programmed cell death. However, it was not until 1965 that the topic was resurrected. While studying tissues using electron microscopy, John Kerr at the University of Queensland was able to distinguish apoptosis from traumatic cell death. Following the publication of a paper describing the phenomenon, Kerr was invited to join Alastair Currie, as well as Andrew Wyllie, who was Currie's graduate student, at the University of Aberdeen. In 1972, the trio published a seminal article in the British Journal of Cancer. Kerr had initially used the term programmed cell necrosis, but in the article, the process of natural cell death was called apoptosis. Kerr, Wyllie and Currie credited James Cormack, a professor of Greek language at University of Aberdeen, with suggesting the term apoptosis. Kerr received the Paul Ehrlich and Ludwig Darmstaedter Prize on March 14, 2000, for his description of apoptosis. He shared the prize with Boston biologist H. Robert Horvitz.
For many years, neither "apoptosis" nor "programmed cell death" was a highly cited term. Two discoveries brought cell death from obscurity to a major field of research: identification of the first component of the cell death control and effector mechanisms, and linkage of abnormalities in cell death to human disease, in particular cancer. This occurred in 1988 when it was shown that BCL2, the gene responsible for follicular lymphoma, encoded a protein that inhibited cell death.
The 2002 Nobel Prize in Medicine was awarded to Sydney Brenner, H. Robert Horvitz and John Sulston for their work identifying genes that control apoptosis. The genes were identified by studies in the nematode C. elegans and homologues of these genes function in humans to regulate apoptosis.
thumb|upright|John Sulston won the Nobel Prize in Medicine in 2002, for his pioneering research on apoptosis.
In Greek, apoptosis translates to the "falling off" of leaves from a tree. Cormack, professor of Greek language, reintroduced the term for medical use as it had a medical meaning for the Greeks over two thousand years before. Hippocrates used the term to mean "the falling off of the bones". Galen extended its meaning to "the dropping of the scabs". Cormack was no doubt aware of this usage when he suggested the name. Debate continues over the correct pronunciation, with opinion divided between a pronunciation with the second p silent ( ) and the second p pronounced (). In English, the p of the Greek -pt- consonant cluster is typically silent at the beginning of a word (e.g. pterodactyl, Ptolemy), but articulated when used in combining forms preceded by a vowel, as in helicopter or the orders of insects: diptera, lepidoptera, etc.
In the original Kerr, Wyllie & Currie paper, there is a footnote regarding the pronunciation:
We are most grateful to Professor James Cormack of the Department of Greek, University of Aberdeen, for suggesting this term. The word "apoptosis" () is used in Greek to describe the "dropping off" or "falling off" of petals from flowers, or leaves from trees. To show the derivation clearly, we propose that the stress should be on the penultimate syllable, the second half of the word being pronounced like "ptosis" (with the "p" silent), which comes from the same root "to fall", and is already used to describe the drooping of the upper eyelid.
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Apoptosis
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Activation mechanisms
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Activation mechanisms
right
thumb|alt=Control Of The Apoptotic Mechanisms|Control of the apoptotic mechanisms
The initiation of apoptosis is tightly regulated by activation mechanisms, because once apoptosis has begun, it inevitably leads to the death of the cell. The two best-understood activation mechanisms are the intrinsic pathway (also called the mitochondrial pathway) and the extrinsic pathway. The intrinsic pathway is activated by intracellular signals generated when cells are stressed and depends on the release of proteins from the intermembrane space of mitochondria. The extrinsic pathway is activated by extracellular ligands binding to cell-surface death receptors, which leads to the formation of the death-inducing signaling complex (DISC).
A cell initiates intracellular apoptotic signaling in response to a stress, which may bring about cell death. The binding of nuclear receptors by glucocorticoids, heat, radiation, nutrient deprivation, viral infection, hypoxia, increased intracellular concentration of free fatty acids and increased intracellular calcium concentration, for example, by damage to the membrane, can all trigger the release of intracellular apoptotic signals by a damaged cell. A number of cellular components, such as poly ADP ribose polymerase, may also help regulate apoptosis. Single cell fluctuations have been observed in experimental studies of stress induced apoptosis.
Before the actual process of cell death is precipitated by enzymes, apoptotic signals must cause regulatory proteins to initiate the apoptosis pathway. This step allows those signals to cause cell death, or the process to be stopped, should the cell no longer need to die. Several proteins are involved, but two main methods of regulation have been identified: the targeting of mitochondria functionality, or directly transducing the signal via adaptor proteins to the apoptotic mechanisms. An extrinsic pathway for initiation identified in several toxin studies is an increase in calcium concentration within a cell caused by drug activity, which also can cause apoptosis via a calcium binding protease calpain.
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Apoptosis
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Intrinsic pathway
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Intrinsic pathway
The intrinsic pathway is also known as the mitochondrial pathway. Mitochondria are essential to multicellular life. Without them, a cell ceases to respire aerobically and quickly dies. This fact forms the basis for some apoptotic pathways. Apoptotic proteins that target mitochondria affect them in different ways. They may cause mitochondrial swelling through the formation of membrane pores, or they may increase the permeability of the mitochondrial membrane and cause apoptotic effectors to leak out. There is also a growing body of evidence indicating that nitric oxide is able to induce apoptosis by helping to dissipate the membrane potential of mitochondria and therefore make it more permeable. Nitric oxide has been implicated in initiating and inhibiting apoptosis through its possible action as a signal molecule of subsequent pathways that activate apoptosis.
During apoptosis, cytochrome c is released from mitochondria through the actions of the proteins Bax and Bak. The mechanism of this release is enigmatic, but appears to stem from a multitude of Bax/Bak homo- and hetero-dimers of Bax/Bak inserted into the outer membrane. Once cytochrome c is released it binds with Apoptotic protease activating factor – 1 (Apaf-1) and ATP, which then bind to pro-caspase-9 to create a protein complex known as an apoptosome. The apoptosome cleaves the pro-caspase to its active form of caspase-9, which in turn cleaves and activates pro-caspase into the effector caspase-3.
Mitochondria also release proteins known as SMACs (second mitochondria-derived activator of caspases) into the cell's cytosol following the increase in permeability of the mitochondria membranes. SMAC binds to proteins that inhibit apoptosis (IAPs) thereby deactivating them, and preventing the IAPs from arresting the process and therefore allowing apoptosis to proceed. IAP also normally suppresses the activity of a group of cysteine proteases called caspases, which carry out the degradation of the cell. Therefore, the actual degradation enzymes can be seen to be indirectly regulated by mitochondrial permeability.
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Apoptosis
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Extrinsic pathway
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Extrinsic pathway
thumb|500px|right|Overview of signal transduction pathways
Two theories of the direct initiation of apoptotic mechanisms in mammals have been suggested: the TNF-induced (tumor necrosis factor) model and the Fas-Fas ligand-mediated model, both involving receptors of the TNF receptor (TNFR) family coupled to extrinsic signals.
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Apoptosis
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TNF pathway
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TNF pathway
TNF-alpha is a cytokine produced mainly by activated macrophages, and is the major extrinsic mediator of apoptosis. Most cells in the human body have two receptors for TNF-alpha: TNFR1 and TNFR2. The binding of TNF-alpha to TNFR1 has been shown to initiate the pathway that leads to caspase activation via the intermediate membrane proteins TNF receptor-associated death domain (TRADD) and Fas-associated death domain protein (FADD). cIAP1/2 can inhibit TNF-α signaling by binding to TRAF2. FLIP inhibits the activation of caspase-8. Binding of this receptor can also indirectly lead to the activation of transcription factors involved in cell survival and inflammatory responses. However, signalling through TNFR1 might also induce apoptosis in a caspase-independent manner. The link between TNF-alpha and apoptosis shows why an abnormal production of TNF-alpha plays a fundamental role in several human diseases, especially in autoimmune diseases. The TNF-alpha receptor superfamily also includes death receptors (DRs), such as DR4 and DR5. These receptors bind to the protein TRAIL and mediate apoptosis. Apoptosis is known to be one of the primary mechanisms of targeted cancer therapy. Luminescent iridium complex-peptide hybrids (IPHs) have recently been designed, which mimic TRAIL and bind to death receptors on cancer cells, thereby inducing their apoptosis.
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Apoptosis
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Fas pathway
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Fas pathway
The fas receptor (First apoptosis signal) – (also known as Apo-1 or CD95) is a transmembrane protein of the TNF family which binds the Fas ligand (FasL). The interaction between Fas and FasL results in the formation of the death-inducing signaling complex (DISC), which contains the FADD, caspase-8 and caspase-10. In some types of cells (type I), processed caspase-8 directly activates other members of the caspase family, and triggers the execution of apoptosis of the cell. In other types of cells (type II), the Fas-DISC starts a feedback loop that spirals into increasing release of proapoptotic factors from mitochondria and the amplified activation of caspase-8.
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Apoptosis
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Common components
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Common components
Following TNF-R1 and Fas activation in mammalian cells a balance between proapoptotic (BAX, BID, BAK, or BAD) and anti-apoptotic (Bcl-Xl and Bcl-2) members of the Bcl-2 family are established. This balance is the proportion of proapoptotic homodimers that form in the outer-membrane of the mitochondrion. The proapoptotic homodimers are required to make the mitochondrial membrane permeable for the release of caspase activators such as cytochrome c and SMAC. Control of proapoptotic proteins under normal cell conditions of nonapoptotic cells is incompletely understood, but in general, Bax or Bak are activated by the activation of BH3-only proteins, part of the Bcl-2 family.
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Apoptosis
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Caspases
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Caspases
Caspases play the central role in the transduction of ER apoptotic signals. Caspases are proteins that are highly conserved, cysteine-dependent aspartate-specific proteases. There are two types of caspases: initiator caspases (caspases 2, 8, 9, 10, 11, and 12) and effector caspases (caspases 3, 6, and 7). The activation of initiator caspases requires binding to specific oligomeric activator protein. Effector caspases are then activated by these active initiator caspases through proteolytic cleavage. The active effector caspases then proteolytically degrade a host of intracellular proteins to carry out the cell death program.
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Apoptosis
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Caspase-independent apoptotic pathway
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Caspase-independent apoptotic pathway
There also exists a caspase-independent apoptotic pathway that is mediated by AIF (apoptosis-inducing factor).
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Apoptosis
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Apoptosis model in amphibians
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Apoptosis model in amphibians
The frog Xenopus laevis serves as an ideal model system for the study of the mechanisms of apoptosis. In fact, iodine and thyroxine also stimulate the spectacular apoptosis of the cells of the larval gills, tail and fins in amphibian's metamorphosis, and stimulate the evolution of their nervous system transforming the aquatic, vegetarian tadpole into the terrestrial, carnivorous frog.
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Apoptosis
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Negative regulators of apoptosis
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Negative regulators of apoptosis
Negative regulation of apoptosis inhibits cell death signaling pathways, helping tumors to evade cell death and developing drug resistance. The ratio between anti-apoptotic (Bcl-2) and pro-apoptotic (Bax) proteins determines whether a cell lives or dies. Many families of proteins act as negative regulators categorized into either antiapoptotic factors, such as IAPs and Bcl-2 proteins or prosurvival factors like cFLIP, BNIP3, FADD, Akt, and NF-κB.
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Apoptosis
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Proteolytic caspase cascade: Killing the cell
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Proteolytic caspase cascade: Killing the cell
Many pathways and signals lead to apoptosis, but these converge on a single mechanism that actually causes the death of the cell. After a cell receives stimulus, it undergoes organized degradation of cellular organelles by activated proteolytic caspases. In addition to the destruction of cellular organelles, mRNA is rapidly and globally degraded by a mechanism that is not yet fully characterized. mRNA decay is triggered very early in apoptosis.
A cell undergoing apoptosis shows a series of characteristic morphological changes. Early alterations include:
Cell shrinkage and rounding occur because of the retraction of lamellipodia and the breakdown of the proteinaceous cytoskeleton by caspases.
The cytoplasm appears dense, and the organelles appear tightly packed.
Chromatin undergoes condensation into compact patches against the nuclear envelope (also known as the perinuclear envelope) in a process known as pyknosis, a hallmark of apoptosis.
The nuclear envelope becomes discontinuous and the DNA inside it is fragmented in a process referred to as karyorrhexis. The nucleus breaks into several discrete chromatin bodies or nucleosomal units due to the degradation of DNA.
Apoptosis progresses quickly and its products are quickly removed, making it difficult to detect or visualize on classical histology sections. During karyorrhexis, endonuclease activation leaves short DNA fragments, regularly spaced in size. These give a characteristic "laddered" appearance on agar gel after electrophoresis. Tests for DNA laddering differentiate apoptosis from ischemic or toxic cell death.
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Apoptosis
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Apoptotic cell disassembly
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Apoptotic cell disassembly
thumb|500px|Different steps in apoptotic cell disassembly
Before the apoptotic cell is disposed of, there is a process of disassembly. There are three recognized steps in apoptotic cell disassembly:
Membrane blebbing: The cell membrane shows irregular buds known as blebs. Initially these are smaller surface blebs. Later these can grow into larger so-called dynamic membrane blebs. An important regulator of apoptotic cell membrane blebbing is ROCK1 (rho associated coiled-coil-containing protein kinase 1).
Formation of membrane protrusions: Some cell types, under specific conditions, may develop different types of long, thin extensions of the cell membrane called membrane protrusions. Three types have been described: microtubule spikes, apoptopodia (feet of death), and beaded apoptopodia (the latter having a beads-on-a-string appearance). Pannexin 1 is an important component of membrane channels involved in the formation of apoptopodia and beaded apoptopodia.
Fragmentation: The cell breaks apart into multiple vesicles called apoptotic bodies, which undergo phagocytosis. The plasma membrane protrusions may help bring apoptotic bodies closer to phagocytes.
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Apoptosis
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Removal of dead cells
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Removal of dead cells
The removal of dead cells by neighboring phagocytic cells has been termed efferocytosis.
Dying cells that undergo the final stages of apoptosis display phagocytotic molecules, such as phosphatidylserine, on their cell surface. Phosphatidylserine is normally found on the inner leaflet surface of the plasma membrane, but is redistributed during apoptosis to the extracellular surface by a protein known as scramblase. These molecules mark the cell for phagocytosis by cells possessing the appropriate receptors, such as macrophages. The removal of dying cells by phagocytes occurs in an orderly manner without eliciting an inflammatory response. During apoptosis cellular RNA and DNA are separated from each other and sorted to different apoptotic bodies; separation of RNA is initiated as nucleolar segregation.
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Apoptosis
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Pathway knock-outs
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Pathway knock-outs
Many knock-outs have been made in the apoptosis pathways to test the function of each of the proteins. Several caspases, in addition to APAF1 and FADD, have been mutated to determine the new phenotype. In order to create a tumor necrosis factor (TNF) knockout, an exon containing the nucleotides 3704–5364 was removed from the gene. This exon encodes a portion of the mature TNF domain, as well as the leader sequence, which is a highly conserved region necessary for proper intracellular processing. TNF-/- mice develop normally and have no gross structural or morphological abnormalities. However, upon immunization with SRBC (sheep red blood cells), these mice demonstrated a deficiency in the maturation of an antibody response; they were able to generate normal levels of IgM, but could not develop specific IgG levels. Apaf-1 is the protein that turns on caspase 9 by cleavage to begin the caspase cascade that leads to apoptosis. Since a -/- mutation in the APAF-1 gene is embryonic lethal, a gene trap strategy was used in order to generate an APAF-1 -/- mouse. This assay is used to disrupt gene function by creating an intragenic gene fusion. When an APAF-1 gene trap is introduced into cells, many morphological changes occur, such as spina bifida, the persistence of interdigital webs, and open brain. In addition, after embryonic day 12.5, the brain of the embryos showed several structural changes. APAF-1 cells are protected from apoptosis stimuli such as irradiation. A BAX-1 knock-out mouse exhibits normal forebrain formation and a decreased programmed cell death in some neuronal populations and in the spinal cord, leading to an increase in motor neurons.
The caspase proteins are integral parts of the apoptosis pathway, so it follows that knock-outs made have varying damaging results. A caspase 9 knock-out leads to a severe brain malformation . A caspase 8 knock-out leads to cardiac failure and thus embryonic lethality . However, with the use of cre-lox technology, a caspase 8 knock-out has been created that exhibits an increase in peripheral T cells, an impaired T cell response, and a defect in neural tube closure . These mice were found to be resistant to apoptosis mediated by CD95, TNFR, etc. but not resistant to apoptosis caused by UV irradiation, chemotherapeutic drugs, and other stimuli. Finally, a caspase 3 knock-out was characterized by ectopic cell masses in the brain and abnormal apoptotic features such as membrane blebbing or nuclear fragmentation . A remarkable feature of these KO mice is that they have a very restricted phenotype: Casp3, 9, APAF-1 KO mice have deformations of neural tissue and FADD and Casp 8 KO showed defective heart development, however, in both types of KO other organs developed normally and some cell types were still sensitive to apoptotic stimuli suggesting that unknown proapoptotic pathways exist.
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Apoptosis
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Methods for distinguishing apoptotic from necrotic cells
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Methods for distinguishing apoptotic from necrotic cells
thumb|Long-term live cell imaging (12h) of multinucleated mouse pre-Adipocyte trying to undergo mitosis. Due to the excess of genetic material the cell fails to replicate and dies by apoptosis.
Label-free live cell imaging, time-lapse microscopy, flow fluorocytometry, and transmission electron microscopy can be used to compare apoptotic and necrotic cells. There are also various biochemical techniques for analysis of cell surface markers (phosphatidylserine exposure versus cell permeability by flow cytometry), cellular markers such as DNA fragmentation (flow cytometry), caspase activation, Bid cleavage, and cytochrome c release (Western blotting). Supernatant screening for caspases, HMGB1, and cytokeratin 18 release can identify primary from secondary necrotic cells. However, no distinct surface or biochemical markers of necrotic cell death have been identified yet, and only negative markers are available. These include absence of apoptotic markers (caspase activation, cytochrome c release, and oligonucleosomal DNA fragmentation) and differential kinetics of cell death markers (phosphatidylserine exposure and cell membrane permeabilization). A selection of techniques that can be used to distinguish apoptosis from necroptotic cells could be found in these references.
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Apoptosis
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Implication in disease
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Implication in disease
thumb|right|220px|A section of mouse liver showing several apoptotic cells, indicated by arrows
thumb|right|220px|A section of mouse liver stained to show cells undergoing apoptosis (orange)
thumb|right|220px|Neonatal cardiomyocytes ultrastructure after anoxia-reoxygenation
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Apoptosis
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Defective pathways
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Defective pathways
The many different types of apoptotic pathways contain a multitude of different biochemical components, many of them not yet understood. As a pathway is more or less sequential in nature, removing or modifying one component leads to an effect in another. In a living organism, this can have disastrous effects, often in the form of disease or disorder. A discussion of every disease caused by modification of the various apoptotic pathways would be impractical, but the concept overlying each one is the same: The normal functioning of the pathway has been disrupted in such a way as to impair the ability of the cell to undergo normal apoptosis. This results in a cell that lives past its "use-by date" and is able to replicate and pass on any faulty machinery to its progeny, increasing the likelihood of the cell's becoming cancerous or diseased.
A recently described example of this concept in action can be seen in the development of a lung cancer called NCI-H460. The X-linked inhibitor of apoptosis protein (XIAP) is overexpressed in cells of the H460 cell line. XIAPs bind to the processed form of caspase-9 and suppress the activity of apoptotic activator cytochrome c, therefore overexpression leads to a decrease in the number of proapoptotic agonists. As a consequence, the balance of anti-apoptotic and proapoptotic effectors is upset in favour of the former, and the damaged cells continue to replicate despite being directed to die. Defects in regulation of apoptosis in cancer cells occur often at the level of control of transcription factors. As a particular example, defects in molecules that control transcription factor NF-κB in cancer change the mode of transcriptional regulation and the response to apoptotic signals, to curtail dependence on the tissue that the cell belongs. This degree of independence from external survival signals, can enable cancer metastasis.
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Apoptosis
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Dysregulation of p53
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Dysregulation of p53
The tumor-suppressor protein p53 accumulates when DNA is damaged due to a chain of biochemical factors. Part of this pathway includes alpha-interferon and beta-interferon, which induce transcription of the p53 gene, resulting in the increase of p53 protein level and enhancement of cancer cell-apoptosis. p53 prevents the cell from replicating by stopping the cell cycle at G1, or interphase, to give the cell time to repair; however, it will induce apoptosis if damage is extensive and repair efforts fail. Any disruption to the regulation of the p53 or interferon genes will result in impaired apoptosis and the possible formation of tumors.
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Apoptosis
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Inhibition
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Inhibition
Inhibition of apoptosis can result in a number of cancers, inflammatory diseases, and viral infections. It was originally believed that the associated accumulation of cells was due to an increase in cellular proliferation, but it is now known that it is also due to a decrease in cell death. The most common of these diseases is cancer, the disease of excessive cellular proliferation, which is often characterized by an overexpression of IAP family members. As a result, the malignant cells experience an abnormal response to apoptosis induction: Cycle-regulating genes (such as p53, ras or c-myc) are mutated or inactivated in diseased cells, and further genes (such as bcl-2) also modify their expression in tumors. Some apoptotic factors are vital during mitochondrial respiration e.g. cytochrome C. Pathological inactivation of apoptosis in cancer cells is correlated with frequent respiratory metabolic shifts toward glycolysis (an observation known as the "Warburg hypothesis".
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Apoptosis
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HeLa cell
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HeLa cell
Apoptosis in HeLa cells is inhibited by proteins produced by the cell; these inhibitory proteins target retinoblastoma tumor-suppressing proteins. These tumor-suppressing proteins regulate the cell cycle, but are rendered inactive when bound to an inhibitory protein. HPV E6 and E7 are inhibitory proteins expressed by the human papillomavirus, HPV being responsible for the formation of the cervical tumor from which HeLa cells are derived. HPV E6 causes p53, which regulates the cell cycle, to become inactive. HPV E7 binds to retinoblastoma tumor suppressing proteins and limits its ability to control cell division. These two inhibitory proteins are partially responsible for HeLa cells' immortality by inhibiting apoptosis to occur.
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Apoptosis
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Treatments
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Treatments
The main method of treatment for potential death from signaling-related diseases involves either increasing or decreasing the susceptibility of apoptosis in diseased cells, depending on whether the disease is caused by either the inhibition of or excess apoptosis. For instance, treatments aim to restore apoptosis to treat diseases with deficient cell death and to increase the apoptotic threshold to treat diseases involved with excessive cell death. To stimulate apoptosis, one can increase the number of death receptor ligands (such as TNF or TRAIL), antagonize the anti-apoptotic Bcl-2 pathway, or introduce Smac mimetics to inhibit the inhibitor (IAPs). The addition of agents such as Herceptin, Iressa, or Gleevec works to stop cells from cycling and causes apoptosis activation by blocking growth and survival signaling further upstream. Finally, adding p53-MDM2 complexes displaces p53 and activates the p53 pathway, leading to cell cycle arrest and apoptosis. Many different methods can be used either to stimulate or to inhibit apoptosis in various places along the death signaling pathway.
Apoptosis is a multi-step, multi-pathway cell-death programme that is inherent in every cell of the body. In cancer, the apoptosis cell-division ratio is altered. Cancer treatment by chemotherapy and irradiation kills target cells primarily by inducing apoptosis.
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Apoptosis
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Hyperactive apoptosis
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Hyperactive apoptosis
On the other hand, loss of control of cell death (resulting in excess apoptosis) can lead to neurodegenerative diseases, hematologic diseases, and tissue damage. Neurons that rely on mitochondrial respiration undergo apoptosis in neurodegenerative diseases such as Alzheimer's and Parkinson's. (an observation known as the "Inverse Warburg hypothesis"). Moreover, there is an inverse epidemiological comorbidity between neurodegenerative diseases and cancer. The progression of HIV is directly linked to excess, unregulated apoptosis. In a healthy individual, the number of CD4+ lymphocytes is in balance with the cells generated by the bone marrow; however, in HIV-positive patients, this balance is lost due to an inability of the bone marrow to regenerate CD4+ cells. In the case of HIV, CD4+ lymphocytes die at an accelerated rate through uncontrolled apoptosis, when stimulated.
At the molecular level, hyperactive apoptosis can be caused by defects in signaling pathways that regulate the Bcl-2 family proteins. Increased expression of apoptotic proteins such as BIM, or their decreased proteolysis, leads to cell death and can cause a number of pathologies, depending on the cells where excessive activity of BIM occurs. Cancer cells can escape apoptosis through mechanisms that suppress BIM expression or by increased proteolysis of BIM.
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Apoptosis
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Treatments
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Treatments
Treatments aiming to inhibit works to block specific caspases. Finally, the Akt protein kinase promotes cell survival through two pathways. Akt phosphorylates and inhibits Bad (a Bcl-2 family member), causing Bad to interact with the 14-3-3 scaffold, resulting in Bcl dissociation and thus cell survival. Akt also activates IKKα, which leads to NF-κB activation and cell survival. Active NF-κB induces the expression of anti-apoptotic genes such as Bcl-2, resulting in inhibition of apoptosis. NF-κB has been found to play both an antiapoptotic role and a proapoptotic role depending on the stimuli utilized and the cell type.
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Apoptosis
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HIV progression
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HIV progression
The progression of the human immunodeficiency virus infection into AIDS is due primarily to the depletion of CD4+ T-helper lymphocytes in a manner that is too rapid for the body's bone marrow to replenish the cells, leading to a compromised immune system. One of the mechanisms by which T-helper cells are depleted is apoptosis, which results from a series of biochemical pathways:
HIV enzymes deactivate anti-apoptotic Bcl-2. This does not directly cause cell death but primes the cell for apoptosis should the appropriate signal be received. In parallel, these enzymes activate proapoptotic procaspase-8, which does directly activate the mitochondrial events of apoptosis.
HIV may increase the level of cellular proteins that prompt Fas-mediated apoptosis.
HIV proteins decrease the amount of CD4 glycoprotein marker present on the cell membrane.
Released viral particles and proteins present in extracellular fluid are able to induce apoptosis in nearby "bystander" T helper cells.
HIV decreases the production of molecules involved in marking the cell for apoptosis, giving the virus time to replicate and continue releasing apoptotic agents and virions into the surrounding tissue.
The infected CD4+ cell may also receive the death signal from a cytotoxic T cell.
Cells may also die as direct consequences of viral infections. HIV-1 expression induces tubular cell G2/M arrest and apoptosis. The progression from HIV to AIDS is not immediate or even necessarily rapid; HIV's cytotoxic activity toward CD4+ lymphocytes is classified as AIDS once a given patient's CD4+ cell count falls below 200.
Researchers from Kumamoto University in Japan have developed a new method to eradicate HIV in viral reservoir cells, named "Lock-in and apoptosis." Using the synthesized compound Heptanoylphosphatidyl L-Inositol Pentakisphophate (or L-Hippo) to bind strongly to the HIV protein PR55Gag, they were able to suppress viral budding. By suppressing viral budding, the researchers were able to trap the HIV virus in the cell and allow for the cell to undergo apoptosis (natural cell death). Associate Professor Mikako Fujita has stated that the approach is not yet available to HIV patients because the research team has to conduct further research on combining the drug therapy that currently exists with this "Lock-in and apoptosis" approach to lead to complete recovery from HIV.
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Apoptosis
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Viral infection
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Viral infection
Viral induction of apoptosis occurs when one or several cells of a living organism are infected with a virus, leading to cell death. Cell death in organisms is necessary for the normal development of cells and the cell cycle maturation. It is also important in maintaining the regular functions and activities of cells.
Viruses can trigger apoptosis of infected cells via a range of mechanisms including:
Receptor binding
Activation of protein kinase R (PKR)
Interaction with p53
Expression of viral proteins coupled to MHC proteins on the surface of the infected cell, allowing recognition by cells of the immune system (such as natural killer and cytotoxic T cells) that then induce the infected cell to undergo apoptosis.
Canine distemper virus (CDV) is known to cause apoptosis in central nervous system and lymphoid tissue of infected dogs in vivo and in vitro.
Apoptosis caused by CDV is typically induced via the extrinsic pathway, which activates caspases that disrupt cellular function and eventually leads to the cells death. In normal cells, CDV activates caspase-8 first, which works as the initiator protein followed by the executioner protein caspase-3. However, apoptosis induced by CDV in HeLa cells does not involve the initiator protein caspase-8. HeLa cell apoptosis caused by CDV follows a different mechanism than that in vero cell lines. This change in the caspase cascade suggests CDV induces apoptosis via the intrinsic pathway, excluding the need for the initiator caspase-8. The executioner protein is instead activated by the internal stimuli caused by viral infection not a caspase cascade.
The Oropouche virus (OROV) is found in the family Bunyaviridae. The study of apoptosis brought on by Bunyaviridae was initiated in 1996, when it was observed that apoptosis was induced by the La Crosse virus into the kidney cells of baby hamsters and into the brains of baby mice.
OROV is a disease that is transmitted between humans by the biting midge (Culicoides paraensis). It is referred to as a zoonotic arbovirus and causes febrile illness, characterized by the onset of a sudden fever known as Oropouche fever.
The Oropouche virus also causes disruption in cultured cells – cells that are cultivated in distinct and specific conditions. An example of this can be seen in HeLa cells, whereby the cells begin to degenerate shortly after they are infected.
With the use of gel electrophoresis, it can be observed that OROV causes DNA fragmentation in HeLa cells. It can be interpreted by counting, measuring, and analyzing the cells of the Sub/G1 cell population. When HeLA cells are infected with OROV, the cytochrome C is released from the membrane of the mitochondria, into the cytosol of the cells. This type of interaction shows that apoptosis is activated via an intrinsic pathway.
In order for apoptosis to occur within OROV, viral uncoating, viral internalization, along with the replication of cells is necessary. Apoptosis in some viruses is activated by extracellular stimuli. However, studies have demonstrated that the OROV infection causes apoptosis to be activated through intracellular stimuli and involves the mitochondria.
Many viruses encode proteins that can inhibit apoptosis. Several viruses encode viral homologs of Bcl-2. These homologs can inhibit proapoptotic proteins such as BAX and BAK, which are essential for the activation of apoptosis. Examples of viral Bcl-2 proteins include the Epstein-Barr virus BHRF1 protein and the adenovirus E1B 19K protein. Some viruses express caspase inhibitors that inhibit caspase activity and an example is the CrmA protein of cowpox viruses. Whilst a number of viruses can block the effects of TNF and Fas. For example, the M-T2 protein of myxoma viruses can bind TNF preventing it from binding the TNF receptor and inducing a response. Furthermore, many viruses express p53 inhibitors that can bind p53 and inhibit its transcriptional transactivation activity. As a consequence, p53 cannot induce apoptosis, since it cannot induce the expression of proapoptotic proteins. The adenovirus E1B-55K protein and the hepatitis B virus HBx protein are examples of viral proteins that can perform such a function.
Viruses can remain intact from apoptosis in particular in the latter stages of infection. They can be exported in the apoptotic bodies that pinch off from the surface of the dying cell, and the fact that they are engulfed by phagocytes prevents the initiation of a host response. This favours the spread of the virus. Prions can cause apoptosis in neurons.
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