Sulfolobales

Sulfolobales
Electron micrograph of Sulfolobus infected with Sulfolobus virus STSV1. Bar = 1 μm.
Scientific classification
Domain:	Archaea
Kingdom:	Proteoarchaeota
Superphylum:	TACK group
Phylum:	Thermoproteota
Class:	Thermoprotei
Order:	Sulfolobales Stetter, 1989
Family
Sulfolobaceae

Sulfolobales is an order of archaeans in the class Thermoprotei.^[1]

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) ^[2] and National Center for Biotechnology Information (NCBI)^[1]

DNA transfer

Exposure of Sulfolobus solfataricus to the DNA damaging agents UV-irradiation, bleomycin or mitomycin C induces cellular aggregation.^[9] Other physical stressors, such as pH or temperature shift, do not induce aggregation, suggesting that induction of aggregation is caused specifically by DNA damage. Ajon et al.^[10] showed that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency. Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Frols et al.^[9][11] and Ajon et al.^[10] hypothesized that the UV-inducible DNA transfer process and subsequent homologous recombinational repair represents an important mechanism to maintain chromosome integrity. This response may be a primitive form of sexual interaction, similar to the more well-studied bacterial transformation that is also associated with DNA transfer between cells leading to homologous recombinational repair of DNA damage.^{[citation needed]} In another related species, Sulfolobus acidocaldarius, UV-irradiation also increases the frequency of recombination due to genetic exchange.^[12]

The ups operon

The ups (UV-induced pilus) operon of Sulfolobus species is highly induced by UV irradiation. The pili encoded by this operon are employed in promoting cellular aggregation, which is necessary for subsequent DNA exchange between cells, resulting in homologous recombination.^[13]

A study of the Sulfolobales acidocaldarius ups operon showed that one of the genes downstream of the operon, saci-1497, encodes an endonuclease III that nicks UV-damaged DNA; and another gene of the operon, saci-1500, encodes a RecQ-like helicase that is able to unwind homologous recombination intermediates such as Holliday junctions.^[13] It was proposed that Saci-1497 and Saci-1500 function in an homologous recombination-based DNA repair mechanism that uses transferred DNA as a template.^[13] Thus it is thought that the ups system in combination with homologous recombination provide a DNA damage response which rescues Sulfolobales from DNA damaging threats.^[13]

See also

• List of Archaea genera

References

Further reading

Scientific journals

• Judicial Commission of the International Committee on Systematics of Prokaryotes (2005). "The nomenclatural types of the orders Acholeplasmatales, Halanaerobiales, Halobacteriales, Methanobacteriales, Methanococcales, Methanomicrobiales, Planctomycetales, Prochlorales, Sulfolobales, Thermococcales, Thermoproteales and Verrucomicrobiales are the genera Acholeplasma, Halanaerobium, Halobacterium, Methanobacterium, Methanococcus, Methanomicrobium, Planctomyces, Prochloron, Sulfolobus, Thermococcus, Thermoproteus and Verrucomicrobium, respectively. Opinion 79". Int. J. Syst. Evol. Microbiol. 55 (Pt 1): 517–518. doi:10.1099/ijs.0.63548-0. PMID 15653928.
• Driessen, Arnold; Yang, Nuan (January 8, 2014). "Deletion of cdvB paralogous genes of Sulfolobus acidocaldarius impairs cell division". Extremophiles. 18 (2): 331–339. doi:10.1007/s00792-013-0618-5. PMID 24399085. S2CID 14445065.
• Euzeby JP; Tindall BJ (2001). "Nomenclatural type of orders: corrections necessary according to Rules 15 and 21a of the Bacteriological Code (1990 Revision), and designation of appropriate nomenclatural types of classes and subclasses. Request for an Opinion". Int. J. Syst. Evol. Microbiol. 51 (Pt 2): 725–727. doi:10.1099/00207713-51-2-725. PMID 11321122.
• Cavalier-Smith, T (2002). "The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification". Int. J. Syst. Evol. Microbiol. 52 (Pt 1): 7–76. doi:10.1099/00207713-52-1-7. PMID 11837318.

Scientific books

• Reysenbach, A-L (2001). "Class I. Thermoprotei class. nov.". In DR Boone; RW Castenholz (eds.). Bergey's Manual of Systematic Bacteriology Volume 1: The Archaea and the deeply branching and phototrophic Bacteria (2nd ed.). New York: Springer Verlag. p. 169. ISBN 978-0-387-98771-2.
• Stetter, KO (1989). "Order III. Sulfolobales ord. nov. Family Sulfolobaceae fam. nov.". In JT Staley; MP Bryant; N Pfennig; JG Holt (eds.). Bergey's Manual of Systematic Bacteriology. Vol. 3 (1st ed.). Baltimore: The Williams & Wilkins Co. p. 169.

External links