Deinococcus–Thermus

Deinococcus–Thermus
Scientific classification
Domain:	Bacteria
Phylum:	Deinococcus–Thermus
Class:	Deinococci Garrity and Holt 2002
Orders & Genera
Deinococcales Rainey et al. 1997 Deinococcaceae Brooks and Murray 1981 emend. Rainey et al. 1997 Deinococcus Brooks and Murray 1981 emend. Rainey et al. 1997 Deinobacterium Ekman et al. 2011 Trueperaceae Rainey et al. 2005 Truepera da Costa, Rainey and Albuquerque 2005 Thermales Rainey and Da Costa 2002 Thermaceae Da Costa and Rainey 2002 Thermus Brock and Freeze 1969 emend. Nobre et al. 1996 Meiothermus Nobre et al. 1996 emend. Albuquerque et al. 2009 Marinithermus Sako et al. 2003 Oceanithermus Miroshnichenko et al. 2003 emend. Mori et al. 2004 Rhabdothermus Steinsbu et al. 2011 Vulcanithermus Miroshnichenko et al. 2003
Synonyms
Hadobacteria Cavalier-Smith 1992 emend. Cavalier-Smith 1998 Xenobacteria

Deinococcus–Thermus is a phylum of bacteria that are highly resistant to environmental hazards.

There are two main groups.

• The Deinococcales include two families, with three genera, Deinococcus and Truepera, the former with several species that are resistant to radiation; they have become famous for their ability to eat nuclear waste and other toxic materials, survive in the vacuum of space and survive extremes of heat and cold.
• The Thermales include several genera resistant to heat (Marinithermus, Meiothermus, Oceanithermus, Thermus, Vulcanithermus). Thermus aquaticus was important in the development of the polymerase chain reaction where repeated cycles of heating DNA to near boiling make it advantageous to use a thermo-stable DNA polymerase enzyme.

Though these two groups evolved from a common ancestor, the two mechanisms of resistance appear to be largely independent.

These bacteria have thick cell walls that give them gram-positive stains, but they include a second membrane and so are closer in structure to those of gram-negative bacteria.

Cavalier-Smith calls this clade Hadobacteria (from Hades, the Greek underworld).

Phylogeny

See also: Bacterial taxonomy

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) and the phylogeny is based on 16S rRNA-based LTP release 111 by 'The All-Species Living Tree' Project

Thermaceae	Rhabdothermus arcticus Steinsbu et al. 2011 Vulcanithermus mediatlanticus Miroshnichenko et al. 2003 Oceanithermus O. desulfurans Mori et al. 2004 O. profundus Miroshnichenko et al. 2003 (type sp.) Marinithermus hydrothermalis Sako et al. 2003 Meiothermus Thermus
Deinococcales	Truepera radiovictrix Albuquerque et al. 2005 Deinococcaceae Deinobacterium chartae Ekman et al. 2011 Deinococcus

Note:
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN)

Sequenced genomes

Currently there are 10 sequenced genomes of strains in this phylum.

• Deinococcus radiodurans R1
• Thermus thermophilus HB27
• Thermus thermophilus HB8
• Deinococcus geothermalis DSM 11300
• Deinococcus deserti VCD115
• Meiothermus ruber DSM 1279
• Meiothermus silvanus DSM 9946
• Truepera radiovictrix DSM 17093
• Oceanithermus profundus DSM 14977

The two Meiothermus species were sequenced under the auspices of the Genomic Encyclopedia of Bacteria and Archaea project (GEBA), which aims at sequencing organisms based on phylogenetic novelty and not on pathogenicity or notoriety. Currently, the genome of Thermus aquaticus Y51MC23 is in the final stages of assembly by the DOE Joint Genome Institute