Deinococcus radiodurans

Prepared by: Mary Jane T. HugoBSE III-General Science

What is Deinococcus radiodurans?

•one of the most radiation-resistant organisms known. •a polyextremophile • the world's toughest bacterium in The Guinness Book Of

World Records• from the Ancient Greek δεινός (deinos) and κόκκος (kokkos)

meaning "terrible grain/berry" and the Latin radius and durare, meaning "radiation surviving". • formerly called Micrococcus radiodurans. •Conan the Bacterium.

Taxonomic Classification

Deinococcus radiodurans

A tetrad of D. radiodurans

Scientific classificationDomain: BacteriaPhylum: Deinococcus-Thermus

Order: Deinococcales

Genus: Deinococcus

Species: D. radiodurans

Binomial nameDeinococcus radiodurans

Brooks & Murray, 1981

History

•discovered in 1956 by Arthur W. Anderson at the Oregon Agricultural Experiment Station in Corvallis, Oregon.•The complete DNA sequence of D. radiodurans was published in 1999 by TIGR.• A detailed annotation and analysis of the genome appeared by Michael Daly and his colleagues (2001).

• rather large, spherical bacterium, with a diameter of 1.5 to 3.5 µm.• ,forms a tetrad. •easily cultured and do not appear to cause disease.• Colonies are smooth, convex, and pink to red in color. •The cells stain Gram positive, cell wall : Gram

negative bacteria• does not form endospores and is nonmotile. • . found in habitats rich in organic materials

Description

•an obligate aerobic chemoorganoheterotroph• It is extremely resistant to ionizing radiation, ultraviolet light, desiccation, and oxidizing and electrophilic agents.•genome consists of two circular chromosomes and many plasmids• its stationary phase, each bacterial cell 4 copies of this genome; rapidly multiplying, each bacterium 8-10 copies of the genome.

Description

Ionizing-radiation resistance

•capable of withstanding an acute dose of 5,000 Gy (500,000 rad) of ionizing radiation with almost no loss of viability, and an acute dose of 15,000 Gy with 37% viability.•has a unique ability to repair damaged DNA.

Mechanisms of ionizing-radiation resistance

• resistance to radiation by having multiple copies of its genome and rapid DNA repair mechanisms. • usually repairs in its chromosomes within 12–24 hours by a

2-step process. 1.single-stranded annealing.2. homologous recombination. • tightly packed into toroids

•capable of genetic transformation, •Michael Daly has suggested the bacterium uses manganese complexes as antioxidants for protection against radiation.(2007)• In 2009, nitric oxide was reported to play an important role in the bacteria's recovery from radiation exposure.

Mechanisms of ionizing-radiation resistance

Applications•genetically engineered for use in bioremediation to consume and digest solvents and heavy metals, even in a highly radioactive site. •For example, the bacterial mercuric reductase gene has been cloned from Escherichia coli into Deinococcus to detoxify the ionic mercury residue

•U.S. scientists demonstrated D. radiodurans could be used as a means of information storage that might survive a nuclear catastrophe (2003).

Applications

•http://web.mst.edu/~microbio/BIO221_2001/deinococcus_radiodurans.html•http://www.genomenewsnetwork.org/articles/07_02/deinoc

occus.shtml•https://microbewiki.kenyon.edu/index.php/Deinococcus_ra

diodurans•http://www.majordifferences.com/2013/10/difference-gram

-positive-vs-gram_2.html#.VrtlS-Kqqkp

References