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Thermococcus Gammatolerans
''Thermococcus gammatolerans'' is an archaea extremophile and the most radiation-resistant organism known to exist. As reported in 2003 the type strain EJ3T was taken from a submarine hydrothermal vent in the Guaymas Basin off the coast of Baja California at a depth of about 2,600 m by submersible Nautile during the 1991 ''Guaynaut'' cruise. ''Thermococcus gammatolerans'' thrives in temperatures between 55 and 95 °C with an optimum development around 88 °C. Its optimal growth pH is 6, favoring the presence of sulfur (S), which is reduced to hydrogen sulfide (). It is the organism with the strongest known resistance to radiation, supporting a radiation of gamma rays from 30,000 gray (Gy). Along with the genera ''Palaeococcus'' and ''Pyrococcus'', ''Thermococcus'' belongs to the Thermococcaceae family, sole family of the Thermococci (called "Protoarchaea" by Cavalier-Smith), a class in the phylum Euryarchaeota of Archaea. ''Thermococcus'' species live in extre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioresistance
Radioresistance is the level of ionizing radiation that organisms are able to withstand. Ionizing-radiation-resistant organisms (IRRO) were defined as organisms for which the dose of acute ionizing radiation (IR) required to achieve 90% reduction (D10) is greater than 1000 gray (Gy) Radioresistance is surprisingly high in many organisms, in contrast to previously held views. For example, the study of environment, animals and plants around the Chernobyl disaster area has revealed an unexpected survival of many species, despite the high radiation levels. A Brazilian study in a hill in the state of Minas Gerais which has high natural radiation levels from uranium deposits, has also shown many radioresistant insects, worms and plants. Certain extremophiles, such as the bacteria ''Deinococcus radiodurans'' and the tardigrades, can withstand large doses of ionizing radiation on the order of 5,000 Gy. Induced radioresistance In the graph on left, a dose/survival curve for a hypoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea Described In 2003
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars (including its own descendants, the Romance languages) supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition. Latin is a highly inflected language, with three distinct genders (masculine, feminine, and neuter), six or seven noun cases (nominative, accusative, genitive, dative, ablative, and vocative), five declensions, four verb conjuga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacterial Cellular Morphologies
Introduction The morphology and arrangement of bacteria are often a key factor in identifying their species. Their direct examination under the light microscope enables the classification of these Bacteria and Archaea . Generally, the basic morphologies are spheres (coccus) and round-ended cylinders or rod shaped (bacillus). But, there are also other morphologies such as helically twisted cylinders (example Spirochetes'), cylinders curved in one plane (selenomonads) and unusual morphologies (the square, flat box-shaped cells of the Archaean genus ''Haloquadratum)''. Other arrangements include pairs, tetrads, clusters, chains and palisades. Coccus A coccus (plural ''cocci'', from the Latin ''coccinus'' (scarlet) and derived from the Greek ''kokkos'' (berry)) is any microorganism (usually bacteria) whose overall shape is spherical or nearly spherical. Describing a bacterium as a coccus, or sphere, distinguishes it from bacillus, or rod. This is the first of many taxonomic tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Latin
New Latin (also called Neo-Latin or Modern Latin) is the revival of Literary Latin used in original, scholarly, and scientific works since about 1500. Modern scholarly and technical nomenclature, such as in zoological and botanical taxonomy and international scientific vocabulary, draws extensively from New Latin vocabulary, often in the form of classical or neoclassical compounds. New Latin includes extensive new word formation. As a language for full expression in prose or poetry, however, it is often distinguished from its successor, Contemporary Latin. Extent Classicists use the term "Neo-Latin" to describe the Latin that developed in Renaissance Italy as a result of renewed interest in classical civilization in the 14th and 15th centuries. Neo-Latin also describes the use of the Latin language for any purpose, scientific or literary, during and after the Renaissance. The beginning of the period cannot be precisely identified; however, the spread of secular education, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grammatical Gender
In linguistics, grammatical gender system is a specific form of noun class system, where nouns are assigned with gender categories that are often not related to their real-world qualities. In languages with grammatical gender, most or all nouns inherently carry one value of the grammatical category called ''gender''; the values present in a given language (of which there are usually two or three) are called the ''genders'' of that language. Whereas some authors use the term "grammatical gender" as a synonym of "noun class", others use different definitions for each; many authors prefer "noun classes" when none of the inflections in a language relate to sex. Gender systems are used in approximately one half of the world's languages. According to one definition: "Genders are classes of nouns reflected in the behaviour of associated words." Overview Languages with grammatical gender usually have two to four different genders, but some are attested with up to 20. #Gender contras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek Language
Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regarded as a separate historical stage, although its earliest form closely resembles Attic Greek and its latest form a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionizing Radiation
Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum. Gamma rays, X-rays, and the higher energy ultraviolet part of the electromagnetic spectrum are ionizing radiation, whereas the lower energy ultraviolet, visible light, nearly all types of laser light, infrared, microwaves, and radio waves are non-ionizing radiation. The boundary between ionizing and non-ionizing radiation in the ultraviolet area is not sharply defined, as different molecules and atoms ionize at different energies. The energy of ionizing radiation starts between 10 electronvolts (eV) and 33 eV. Typical ionizing subatomic particles include alpha particles, beta particles, and neutrons. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaerobic Organism
An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment. Anaerobes may be unicellular (e.g. protozoans, bacteria) or multicellular. Most fungi are obligate aerobes, requiring oxygen to survive. However, some species, such as the Chytridiomycota that reside in the rumen of cattle, are obligate anaerobes; for these species, anaerobic respiration is used because oxygen will disrupt their metabolism or kill them. Deep waters of the ocean are a common anoxic environment. First observation In his letter of 14 June 1680 to The Royal Society, Antonie van Leeuwenhoek described an experiment he carried out by filling two identical glass tubes about halfway with crushed pepper powder, to which some clean rain water was added. Van Leeuwenhoek sealed one of the glass tubes using a flame an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organotrophic
An organotroph is an organism that obtains hydrogen or electrons from organic substrates. This term is used in microbiology to classify and describe organisms based on how they obtain electrons for their respiration processes. Some organotrophs such as animals and many bacteria, are also heterotrophs. Organotrophs can be either anaerobic or aerobic. Antonym: Lithotroph, Adjective: Organotrophic. History The term was suggested in 1946 by André Lwoff, Lwoff and collaborators.Lwoff, A., C.B. van Niel, P.J. Ryan, and E.L. Tatum (1946). Nomenclature of nutritional types of microorganisms. ''Cold Spring Harbor Symposia on Quantitative Biology'' (5th edn.), Vol. XI, The Biological Laboratory, Cold Spring Harbor, NY, pp. 302–303 See also * Autotroph * Chemoorganotroph * Primary nutritional groups References * Michael Allaby. "organotroph." A Dictionary of Zoology. 1999, Retrieved 2012-03-30 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-organotroph.html * The Prokaryotes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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