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Encyclopedia > Deinococcus radiodurans
Deinococcus radiodurans
D. radiodurans
D. radiodurans
Scientific classification
Kingdom: Bacteria
Phylum: Deinococcus-Thermus
Order: Deinococcales
Genus: Deinococcus
Species: D. radiodurans
Binomial name
Deinococcus radiodurans
Brooks & Murray, 1981

Deinococcus radiodurans ("strange berry that withstands radiation", formerly called Micrococcus radiodurans) is an extremophilic bacterium, and is the most radioresistant organism known. While a dose of 10 Gy is sufficient to kill a human, and a dose of 60 Gy is sufficient to kill all cells in a culture of E. coli, D. radiodurans is capable of withstanding an instantaneous dose of up to 5,000 Gy with no loss of viability, and an instantaneous dose of up to 15,000 Gy with 37% viability. It can survive heat, cold, dehydration, vacuum, and acid, and because of its resistance to more than one extreme condition, D. radiodurans is known as a polyextremophile. It has also been listed as the world's toughest bacterium in "The Guiness Book Of World Records" because of its extraordinary resistance to several extreme conditions. It has been classified as a Gram-positive bacterium. Image File history File links Deinococcus_radiodurans. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Orders & Genera Deinococcales     Deinococcus Thermales     Thermus     Meiothermus     Marinithermus     Oceanithermus     Vulcanithermus The Deinococcus-Thermus are a small group of bacteria comprised of cocci highly resistant to environmental hazards. ... Binomial name Deinococcus radiodurans Brooks & Murray, 1981 Deinococcus radiodurans (former Micrococcus radiodurans) is an extremophilic bacterium, and is the most radiation-resistant organism known. ... Binomial name Deinococcus radiodurans Brooks & Murray, 1981 Deinococcus radiodurans (former Micrococcus radiodurans) is an extremophilic bacterium, and is the most radiation-resistant organism known. ... This article does not cite any references or sources. ... An extremophile is an organism, usually unicellular, which thrives in or requires extreme conditions that would exceed optimal conditions for growth and reproduction in the majority of mesophilic terrestrial organisms. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Radioresistant organisms are capable of living in environments with very high levels of ionizing radiation, such as nuclear power plants. ... The gray (symbol: Gy) is the SI unit of absorbed dose. ... Binomial name Escherichia coli T. Escherich, 1885 Escherichia coli (usually abbreviated to E. coli) is one of the main species of bacteria that live in the lower intestines of warm-blooded animals (including birds and mammals) and are necessary for the proper digestion of food. ... For other uses, see Acid (disambiguation). ... This page is a candidate to be copied to Wiktionary. ... Gram-positive Bacillus anthracis bacteria (purple rods) in cerebrospinal fluid sample. ...



The term Deinobacter has been replaced by Deinococcus based on evaluation of ribosomal RNA sequences. Several other species within the genus have been described, and they are related to heat-resistant bacteria such as Thermus; the group is accordingly known as Deinococcus-Thermus. Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers that plays several important roles in the processes that translate genetic information from deoxyribonucleic acid (DNA) into protein products; RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes, forms vital portions... Binomial name Thermus aquaticus Thermus aquaticus is a species of bacterium that is the source of the enzyme Taq DNA Polymerase, one of the most important enzymes in molecular biology. ... Orders & Genera Deinococcales     Deinococcus Thermales     Thermus     Meiothermus     Marinithermus     Oceanithermus     Vulcanithermus The Deinococcus-Thermus are a small group of bacteria comprised of cocci highly resistant to environmental hazards. ...

Contents

History

D. radiodurans was discovered in 1956 by A.W. Anderson at the Oregon Agricultural Experiment Station in Corvallis, Oregon. Experiments were being performed to determine if canned food could be sterilized using high doses of gamma radiation. A tin of meat was exposed to a dose of radiation that was thought to kill all known forms of life, but the meat subsequently spoiled. D. radiodurans was isolated from the meat. Corvallis (IPA: ) is a city located in central western Oregon, USA. It is the county seat of Benton CountyGR6 and the principal city of the Corvallis, Oregon Metropolitan Statistical Area, which encompasses all of Benton County. ... This article is about electromagnetic radiation. ...


Radioactivity resistance mechanisms

Deinococcus accomplishes its resistance to radiation by having multiple copies of its genome and rapid DNA repair mechanisms. It usually repairs breaks in its chromosomes within 12-24 hours through a 2-step process. First, D. radiodurans reconnects some chromosome fragments through a process called single-strand annealing. In the second step, a protein mends double-strand breaks through homologous recombination. As a consequence of its hardiness it has been nicknamed "Conan the Bacterium" (after Conan the Barbarian). In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... This article or section seems to contain too many examples (or of a poor quality) for an encyclopedia entry. ... Hither came Conan, the Cimmerian, black-haired, sullen-eyed, sword in hand, a thief, a reaver, a slayer, with gigantic melancholies and gigantic mirth, to tread the jeweled thrones of the Earth under his sandalled feet. ...


A persistent question regarding D. radiodurans is how such a high degree of radioresistance could evolve. Natural background radiation levels are very low -- in most places, on the order of 0.4 mGy per year, and the highest known background radiation, near Guarapari, Brazil is only 175 mGy per year. With naturally-occurring background radiation levels so low, organisms evolving mechanisms specifically to ward off the effects of high radiation are unlikely. Background radiation is the ionizing radiation emitted from a variety of natural and artificial radiation sources: sources in the Earth and from those sources that are incorporated in our food and water, which are incorporated in our body, and in building materials and other products that incorporate those radioactive sources... Guarapari is a coastal town on the coast of Espírito Santo, Brazil. ...


Valerie Mattimore and John R. Battista of Louisiana State University have suggested that the radioresistance of D. radiodurans is simply a side-effect of a mechanism for dealing with prolonged cellular desiccation (dryness). To support this hypothesis, they performed an experiment in which they demonstrated that mutant strains of D. radiodurans which are highly susceptible to damage from ionizing radiation are also highly susceptible to damage from prolonged desiccation, while the wild type strain is resistant to both [1]. In addition to DNA repair, D. radiodurans use LEA (Late Embryogenesis Abundant) protein[2] expression to protect against desiccation[3]. For other uses, see LSU (disambiguation). ... Desiccation is the state of extreme dryness, or the process of extreme drying. ... Radiation hazard symbol. ... Embryogenesis is the process by which the embryo is formed and develops. ...


Michael Daly of the Uniformed Services University of the Health Sciences suggests that the bacterium uses manganese to protect itself against radiation damage[4]. General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ...


Scanning electron microscopy analysis has shown that DNA in D. radiodurans is organized into tightly packed toroids, which may facilitate DNA repair[5]. The electron microscope is a microscope that can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. ... A toroid is a doughnut-shaped object whose surface is a torus. ...


A team of Croatian and French researchers have bombarded D. radiodurans to study the mechanism of DNA repair. At least two copies of the genome, with random DNA breaks, can form DNA fragments through annealing. Partially overlapping fragments are then used for synthesis of homologous regions through a moving D-loop that can continue extension until they find complementary partner strands. In the final step there is crossover by means of RecA-dependent homologous recombination [6]. Annealing, in genetics, means for DNA or RNA to pair by hydrogen bonds to a complementary sequence, forming a double-stranded polynucleotide. ... In biology, homology is any similarity between structures that is due to their shared ancestry. ... The word complement (with an e in the second syllable, not to be confused with a different word, compliment with an i) has a number of uses. ... Thomas Hunt Morgans illustration of crossing over (1916) Homologous Recombination is the process by which two chromosomes, paired up during prophase I of meiosis, exchange some distal portion of their DNA. Crossover occurs when two chromosomes, normally two homologous instances of the same chromosome, break and then reconnect but... RecA is a protein. ... Thomas Hunt Morgans illustration of crossing over (1916) Homologous Recombination is the process by which two chromosomes, paired up during prophase I of meiosis, exchange some distal portion of their DNA. Crossover occurs when two chromosomes, normally two homologous instances of the same chromosome, break and then reconnect but...


A team of Russian and American scientists proposed that the radioresistance of D. radiodurans had a Martian origin. Evolution of the microorganism could have taken place on the Martian surface until it was delivered to Earth on a meteorite. [7]. It has been hypothesised that such objects might have attained sufficient kinetic energy to achieve escape velocity as a result of a major meteorite impact on the Martian surface (this being part of a hypothecised process known as panspermia). The heating effects of that impact and of entry into the Earth's atmosphere would have had to have been insufficient to sterilise such an object. However, apart from its resistance to radiation, Deinococcus is genetically and biochemically quite similar to other terrestrial life forms, arguing against an extraterrestrial origin. Panspermia is a proven process (based on the principles of Biology, Microbiology, Physics, Chemistry, Astronomy, and assumption that life existed already in the universe) that explains how all life in the universe and/or solar system comes from a seed of life. ...


Applications

Using genetic engineering Deinococcus has been used for bioremediation to consume and digest solvents and heavy metals, even in a highly radioactive site. The bacterial mercuric reductase gene has been cloned from Escherichia coli into Deinococcus to detoxify the ionic mercury frequently found in radioactive waste generated from nuclear weapons manufacture[8]. Those researchers developed a strain of Deinococcus that could detoxify both mercury and toluene in mixed radioactive wastes. An iconic image of genetic engineering; this autoluminograph from 1986 of a glowing transgenic tobacco plant bearing the luciferase gene, illustrating the possibilities of genetic engineering. ... Bioremediation can be defined as any process that uses microorganisms, fungi, green plants or their enzymes to return the environment altered by contaminants to its original condition. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... A heavy metal is any of a number of higher atomic weight elements, which has the properties of a metallic substance at room temperature. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... For a non-technical introduction to the topic, see Introduction to Genetics. ... Molecular cloning refers to the procedure of isolating a defined DNA sequence and obtaining multiple copies of it in vivo. ... E. coli redirects here. ... This article is about the electrically charged particle. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery Standard atomic weight 200. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 kilometers (11 mi) above the hypocenter A nuclear weapon derives its destructive force from nuclear reactions of fusion or fission. ... In biology, Strain can be used two ways. ... Toluene, also known as methylbenzene or phenylmethane is a clear, water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. ...


Some have speculated that mechanisms of DNA repair used by D. radiodurans could be incorporated into the genome of higher species as a means of rejuvenation[6]. DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... The hierarchy of scientific classification. ... Rejuvenation is the procedure of reversing the aging process, thus regaining youth. ...


Some scientists have suggested that D. radiodurans could be genetically manipulated to produce various medicines.



The Craig Venter Institute has used a system derived from the rapid DNA repair mechanisms of D. radiodurans to assemble synthetic genes into chromosomes to make synthetic organisms [9]. Dr. Venter (right) with Michael Janich on his visit in Hong Kong in December 2004 J. Craig Venter (born John Craig Venter October 14, 1946, Salt Lake City) is an American biologist and businessman. ...


Trivia

  • The computer game Anarchy Online features an item called Deinococcus radiodurans which is used to make a "stim" (potion) that reduces damage from radioactive sources.

Anarchy Online (AO) [1] is a science fiction MMORPG released in June 2001 by Funcom set on the world of Rubi-Ka and its extra-dimensional twin, the Shadowlands. ...

References

  1. ^ Mattimore V, Battista JR (1996). "Radioresistance of Deinococcus radiodurans: functions necessary to survive ionizing radiation are also necessary to survive prolonged desiccation". JOURNAL OF BACTERIOLOGY 178 (3): 633–637. PMID 8550493. 
  2. ^ Goyal K, Walton LJ, Tunnacliffe A (2005). "LEA proteins prevent protein aggregation due to water stress". BIOCHEMICAL JOURNAL 388 (Part 1): 151–157. PMID 15631617. 
  3. ^ Battista JR, Park MJ, McLemore AE (2001). "Inactivation of two homologues of proteins presumed to be involved in the desiccation tolerance of plants sensitizes Deinococcus radiodurans R1 to desiccation". CRYOBIOLOGY 43 (2): 133–139. PMID 11846468. 
  4. ^ Pearson, Helen (30 September 2004). Secret of radiation-proof bugs proposed. Internal antioxidants may shield cells from radiation damage. news@nature.com. Retrieved on 2006-06-19.
  5. ^ Levin-Zaidman S, Englander J, Shimoni E, Sharma AK, Minton KW, Minsky A (2003). "Ringlike structure of the Deinococcus radiodurans genome: a key to radioresistance?". SCIENCE 299 (5604): 254–256. PMID 12522252. 
  6. ^ a b Zahradka K, Slade D, Bailone A, Sommer S, Averbeck D, Petranovic M, Lindner AB, Radman M (2006). "Reassembly of shattered chromosomes in Deinococcus radiodurans". NATURE 443 (7111): 569-573. PMID 17006450. 
  7. ^ Pavlov AK, Kalinin VL, Konstantinov AN, Shelegedin VN, Pavlov AA (2006). "Was Earth ever infected by martian biota? Clues from radioresistant bacteria". ASTROBIOLOGY 6 (6): 911-918. PMID 17155889. 
  8. ^ Brim H, McFarlan SC, Fredrickson JK, Minton KW, Zhai M, Wackett LP, Daly MJ (2000). "Engineering Deinococcus radiodurans for metal remediation in radioactive mixed waste environments". NATURE BIOTECHNOLOGY 18 (1): 85–90. PMID 10625398. 
  9. ^ Craig Venter at TED talks mentions D. radiodurans as the ultimate genome assembly machine http://www.ted.com/index.php/talks/view/id/6

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 170th day of the year (171st in leap years) in the Gregorian calendar. ... Science is the journal of the American Association for the Advancement of Science (AAAS). ...

See also

DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... Rejuvenation is the procedure of reversing the aging process, thus regaining youth. ... A game of Core War running under the pMARS simulator, as seen through the graphical core display. ...

External links

  • Microbe of the Week page from the University of Missouri-Rolla
  • Taxonomy of Deinococcus
  • Microbial Biorealm entry from Kenyon College
  • Downloadable D. radiodurans publications
  • Deinococcus radiodurans Genome Page

  Results from FactBites:
 
Deinococcus radiodurans - Wikipedia, the free encyclopedia (485 words)
Deinococcus radiodurans (former Micrococcus radiodurans) is an extremophilic bacterium, and is the most radioresistant organism known.
While a dose of 10 Gy is sufficient to kill a human, and a dose of 60 Gy is sufficient to kill all cells in a culture of E.
Radioresistance of Deinococcus radiodurans: functions necessary to survive ionizing radiation are also necessary to survive prolonged desiccation, PMID 8550493
Deinococcus radiodurans (502 words)
Deinococcus radiodurans was isolated from a can of ground meat that had spoiled despite having been sterilized with radiation.
Deinococcus radiodurans is a gram-positive, non-sporeforming, aerobe that requires a very complex media to produce pink to reddish colonies.
It is believed that Deinococcus radiodurans has evolved to survive long periods of dehydration, and that the resistance to radiation is only incidental to the discovery and development of radiation emitting technology during the second half of this century.
  More results at FactBites »

 
 

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