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Transmissible Cancers
A transmissible cancer is a cancer cell or cluster of cancer cells that can be transferred between individuals without the involvement of an infectious agent such as an oncovirus. The evolution of transmissible cancer has occurred naturally in other animal species, but human cancer transmission is rare. This transfer is typically between members of the same species or closely related species. General mechanism Transmissible cancers require a specific combination of related circumstances to occur. These conditions involve both the host species and the tumors being transferred. These typically include low genetic diversity among individuals, an effective physical and environmental transport system, and a high enough dose of infective material. The cancers reproduce faster in larger quantities with different means of reproduction tend to be favored for transmission if host conditions are met. Transmissible cancers follow the general pattern of cancer spread, starting with the grow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible Signs and symptoms of cancer, signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in defecation, bowel movements. While these symptoms may indicate cancer, they can also have other causes. List of cancer types, Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor Diet (nutrition), diet, sedentary lifestyle, lack of physical activity or Alcohol abuse, excessive alcohol consumption. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. infectious causes of cancer, Infection with specific viruses, bacteria and parasites is an environmental factor cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Bottleneck
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as genocide, speciocide, widespread violence or intentional culling. Such events can reduce the variation in the gene pool of a population; thereafter, a smaller population, with a smaller genetic diversity, remains to pass on genes to future generations of offspring. Genetic diversity remains lower, increasing only when gene flow from another population occurs or very slowly increasing with time as random mutations occur. This results in a reduction in the robustness of the population and in its ability to adapt to and survive selecting environmental changes, such as climate change or a shift in available resources. Alternatively, if survivors of the bottleneck are the individuals with the greatest genetic fitness, the frequency of the fitter genes within the gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mytilus Trossulus
''Mytilus trossulus'', the Pacific blue mussel, bay mussel or foolish mussel, is a medium-sized edible marine bivalve mollusc in the family Mytilidae. ''Mytilus trossulus'' is one of the three principal, closely related taxa in the ''Mytilus edulis'' complex of blue mussels, which collectively are widely distributed on the temperate to subarctic coasts the Northern Hemisphere, and often are dominant inhabitants on hard substrates of the intertidal and nearshore habitats. Distribution ''Mytilus trossulus'' is the main native intertidal mussel in the Northern Pacific. In North America it is found from California to Alaska, and in Asia from Hokkaido northwards. At its southern limits, it hybridizes with '' Mytilus galloprovincialis'' (the Mediterranean mussel), which has been introduced to the Pacific by human activity. In the North Atlantic, ''M. trossulus'' is found on the U.S. coast of Maine and northwards to Canada, as well as in scattered localities on North European coasts. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Geographic (magazine)
''National Geographic'' (formerly ''The National Geographic Magazine'', sometimes branded as ''Nat Geo'') is an American monthly magazine published by National Geographic Partners. The magazine was founded in 1888 as a scholarly journal, nine months after the establishment of the society, but is now a popular magazine. In 1905, it began including pictures, a style for which it became well known. Its first color photos appeared in the 1910s. During the Cold War, the magazine committed itself to present a balanced view of the physical geography, physical and human geography of countries beyond the Iron Curtain. Later, the magazine became outspoken on Environmentalism, environmental issues. Until 2015, the magazine was completely owned and managed by the National Geographic Society. Since 2015, controlling interest has been held by National Geographic Partners. Topics of features generally concern geography, history, nature, science, and world culture. The magazine is well known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukemia
Leukemia ( also spelled leukaemia; pronounced ) is a group of blood cancers that usually begin in the bone marrow and produce high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or '' leukemia cells''. Symptoms may include bleeding and bruising, bone pain, fatigue, fever, and an increased risk of infections. These symptoms occur due to a lack of normal blood cells. Diagnosis is typically made by blood tests or bone marrow biopsy. The exact cause of leukemia is unknown. A combination of genetic factors and environmental (non-inherited) factors are believed to play a role. Risk factors include smoking, ionizing radiation, petrochemicals (such as benzene), prior chemotherapy, and Down syndrome. People with a family history of leukemia are also at higher risk. There are four main types of leukemia—acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL) and chronic myelo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soft-shell Clam
Soft-shell clams (American English) or Sand gaper (British English/Europe), scientific name ''Mya arenaria'', popularly called "steamers", "softshells", "piss clams", "Ipswich clams", or "Essex clams", are a species of edible saltwater clam, a marine bivalve mollusk in the family Myidae. Right and left valve of the same specimen: Mya arenaria 01.jpg, Right valve Mya arenaria 02.jpg, Left valve Habitat and distribution These clams live buried in the sediment on tidal flats. While they are common in muddy areas, their name "arenaria" means sandy and they prefer a combination of sandy and muddy areas. They are well known as a food item on the coast of New England in the Western Atlantic Ocean; however, the range extends much farther north to Canada and south to the Southern states. They are also found in the Eastern Atlantic Ocean, for example in the UK, as well as in the North Sea's Wadden Sea (where they are the dominant large clam). This species has become invasive o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devil Facial Tumour Disease
Devil facial tumour disease (DFTD) is an aggressive non-viral clonally transmissible cancer which affects Tasmanian devils, a marsupial native to the Australian island of Tasmania. The cancer manifests itself as lumps of soft and ulcerating tissue around the mouth, which may invade surrounding organs and metastasise to other parts of the body. Severe genetic abnormalities exist in cancer cells—for example, DFT2 cells are tetraploid, containing twice as much genetic material as normal cells. DFTD is most often spread by bites, when teeth come into contact with cancer cells; less important pathways of transmission are ingesting of infected carcasses and sharing of food. Adult Tasmanian devils who are otherwise the fittest are most susceptible to the disease. DFTD is estimated to have first developed in 1986. There are two currently existing strains, both appearing to be derived from Schwann cells. DFT1 is the main and older strain that infects most of the devil population. It wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aedes Aegypti
''Aedes aegypti'' ( or from Greek 'hateful' and from Latin, meaning 'of Egypt'), sometimes called the Egyptian mosquito, dengue mosquito or yellow fever mosquito, is a mosquito that spreads diseases like dengue fever, yellow fever, malaria, and chikungunya. The mosquito can be recognized by black and white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. This mosquito originated in Africa, but is now a common invasive species that has spread to tropical, subtropical, and temperate regions throughout the world. Biology ''Aedes aegypti'' is a , dark mosquito which can be recognized by white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. Females are larger than males. Microscopically females possess small palps tipped with silver or white scales, and their antennae have sparse short hairs, whereas those of males are feathery. ''Aedes aegypti'' can be confused with ''Aedes albopic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contagious Reticulum Cell Sarcoma
Contagious reticulum cell sarcoma is a reticulum-cell sarcoma found in Syrian hamsters that can be transmitted from one hamster to another. It was first described in 1945. Transmission from hamster to hamster can be through various mechanisms. It has been seen to spread within a laboratory population, presumably through gnawing at tumours and cannibalism. It can also be spread by means of the bite of the mosquito ''Aedes aegypti''. It is one of only three known transmissible cancers in mammals; the others are devil facial tumor disease, a cancer which occurs in Tasmanian devil The Tasmanian devil (''Sarcophilus harrisii''; palawa kani: ''purinina'') is a carnivorous marsupial of the family Dasyuridae. It was formerly present across mainland Australia, but became extinct there around 3,500 years ago; it is now con ...s, and canine transmissible venereal tumor in dogs and other canines. Unlike these other two, tumours with multiple, independent origins have been observed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Culture
Cell culture or tissue culture is the process by which cell (biology), cells are grown under controlled conditions, generally outside of their natural environment. After cells of interest have been Cell isolation, isolated from living tissue, they can subsequently be maintained under carefully controlled conditions. They need to be kept at body temperature (37 °C) in an incubator. These conditions vary for each cell type, but generally consist of a suitable vessel with a substrate or rich growth medium, medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones, and gases (Carbon dioxide, CO2, Oxygen, O2), and regulates the physio-chemical environment (Buffer solution, pH buffer, osmotic pressure, temperature). Most cells require a surface or an artificial substrate to form an adherent culture as a monolayer (one single-cell thick), whereas others can be grown free floating in a medium as a suspension culture. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canine Transmissible Venereal Tumor
A canine transmissible venereal tumor (CTVT), also known as a transmissible venereal tumor (TVT), canine transmissible venereal sarcoma (CTVS), sticker tumor and infectious sarcoma, is a histiocytic tumor of the external genitalia of the dog and other canines, and is transmitted from animal to animal during mating. It is one of only three known transmissible cancers in mammals; the others are devil facial tumor disease, a cancer which occurs in Tasmanian devils, and contagious reticulum cell sarcoma of the Syrian hamster. The tumor cells are themselves the infectious agents, and the tumors that form are not genetically related to the host dog. Although the genome of a CTVT is derived from an individual canid (specifically from a population of Native American dogs with coyote contribution), it is now essentially living as a unicellular, asexually reproducing (but sexually transmitted) pathogen. Sequence analysis of the genome suggests it diverged from canids over 6,000 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is distinguished from '' genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
