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Fluorine, a poisonous gas in its elemental form at biological temperatures, has been a subject of significant interest for a broad range of biological applications, including ecology, medical science, and biochemical engineering. Among the most reactive of the elements, it has proved valuable in many potent industrial compounds, such as the weak (but very toxic) acid hydrogen fluoride, which are quite dangerous to living organisms. Fluorine is a component of so-called "1080" poison, a mammal-killer banned in much of the world but still used to control populations of Australian foxes and American coyotes. Because carbon-fluorine bonds are difficult to form, they are seldom found in nature. A few species of plants and bacteria found in the tropics make fluorine-containing poisons to deter predators from eating them. The same bond makes fluorination a powerful lever for new drug design, allowing the tweaking of organic molecules in innovative ways which has led to several blockbuster commercial successes, such as Lipitor and Prozac. In dental products, when applied topically the fluoride ion chemically binds to surface tooth enamel, making it marginally more acid-resistant. Although politically controversial, fluoridation of public water supplies has shown consistent benefits to dental hygiene, especially for poor children. Manmade fluorinated compounds have also played roles in several noteworthy environmental concerns. Chlorofluorocarbons, once major components of numerous commercial aerosol products, have proven damaging to the Earth's ozone layer and resulted in the wide-reaching Montreal Protocol (though in truth the chlorine in CFCs is the destructive actor, fluorine is an important part of these molecules because it makes them very stable and long-lived). Similarly, the stability of many organofluorines has raised the issue of biopersistence. Long-lived molecules from waterproofing sprays, PFOA and PFOS, are found worldwide in wildlife and humans, including newborn children. Fluorine biology is also relevant to a number of cutting-edge technologies. PFCs (perfluorocarbons) are capable of holding enough oxygen to support human liquid breathing. Several works of science fiction have touched on this, but in the real world, researchers have experimented with PFCs for burned lung care and as blood substitutes. Fluorine in the form of its radioisotope F-18 is also at the heart of a modern medical imaging technique known as positron emission tomography (PET). A PET scan produces three-dimensional colored images of parts of the body that use a lot of sugar, particularly the brain or tumors. ==Natural biochemistry== Biologically synthesized organofluorines have been found in microorganisms and plants, but not in animals. The most common example is fluoroacetate, with an active poison molecule identical to commercial "1080". It is used as a defense against herbivores by at least 40 green plants in Australia, Brazil, and Africa; other biologically synthesized organofluorines include ω-fluoro fatty acids, fluoroacetone, and 2-fluorocitrate.〔 In bacteria, the enzyme adenosyl-fluoride synthase, which makes the carbon–fluorine bond, has been isolated. The discovery was touted as possibly leading to biological routes for organofluorine synthesis. Fluoride is not considered an essential mineral element for mammals and humans. Small amounts of fluoride may be beneficial for bone strength, but this is an issue only in the formulation of artificial diets. See also "Fluoride deficiency". 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Biological aspects of fluorine」の詳細全文を読む スポンサード リンク
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