Editing Thermophile (section)

== Gene transfer and genetic exchange ==

''[[Sulfolobus solfataricus]]'' and ''[[Sulfolobus acidocaldarius]]'' are [[Hyperthermophile|hyperthermophilic]] [[Archaea]].  When these organisms are exposed to the [[DNA damaging agent]]s [[UV radiation|UV irradiation]], [[bleomycin]] or [[mitomycin C]], species-specific cellular aggregation is induced.<ref name=Frols08>{{cite journal |display-authors=6 |author=Fröls S |author2=Ajon M |author3=Wagner M |author4=Teichmann D |author5=Zolghadr B |author6= Folea M |author7=Boekema EJ |author8=Driessen AJ |author9=Schleper C |author10=Albers SV |title=UV-inducible cellular aggregation of the hyperthermophilic archaeon Sulfolobus solfataricus is mediated by pili formation |journal=Mol. Microbiol. |volume=70 |issue=4 |pages=938–52 |date=November 2008 |pmid=18990182 |doi=10.1111/j.1365-2958.2008.06459.x |url=https://www.rug.nl/research/portal/files/56956856/UV_inducible_cellular_aggregation_of_the_hyperthermophilic_archaeon_Sulfolobus_solfataricus_is_mediated_by_pili_formation.pdf |doi-access=free }}</ref><ref name=Ajon>{{cite journal |author1=Ajon M |author2= Fröls S |author3=van Wolferen M |author4=Stoecker K |author5=Teichmann D |author6=Driessen AJ |author7=Grogan DW |author8=Albers SV |author9=Schleper C |display-authors=5 |title=UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili |journal=Mol. Microbiol. |volume=82 |issue=4 |pages=807–17 |date=November 2011 |pmid=21999488 |doi=10.1111/j.1365-2958.2011.07861.x |url=https://pure.rug.nl/ws/files/6771142/2011MolMicrobiolAjon.pdf |doi-access=free }}</ref>  In ''S. acidocaldarius'', UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency.<ref name=Ajon />  Recombination rates exceed those of uninduced cultures by up to three orders of magnitude.  Frols et al.<ref name=Frols08 /><ref>{{cite journal |author=Fröls S |author2=White MF |author3=Schleper C |title=Reactions to UV damage in the model archaeon Sulfolobus solfataricus |journal=Biochem. Soc. Trans. |volume=37 |issue=Pt 1 |pages=36–41 |date=February 2009 |pmid=19143598 |doi=10.1042/BST0370036 }}</ref> and Ajon et al.<ref name=Ajon />(2011) hypothesized that cellular aggregation enhances species-specific DNA transfer between ''Sulfolobus'' cells in order to provide increased repair of damaged DNA by means of [[homologous recombination]].  Van Wolferen et al., in discussing DNA exchange in the hyperthermophiles under extreme conditions, noted that DNA exchange likely plays a role in repair of DNA via homologous recombination.  They suggested that this process is crucial under DNA damaging conditions such as high temperature.  Also it has been suggested that DNA transfer in ''Sulfolobus'' may be a primitive form of sexual interaction similar to the more well-studied [[bacterial transformation]] systems that are associated with species-specific DNA transfer between cells leading to homologous recombinational repair of DNA damage.<ref>{{cite journal |author=van Wolferen M |author2=Ajon M |author3=Driessen AJ |author4=Albers SV |title=How hyperthermophiles adapt to change their lives: DNA exchange in extreme conditions |journal=Extremophiles |volume=17 |issue=4 |pages=545–63 |date=July 2013 |pmid=23712907 |doi=10.1007/s00792-013-0552-6 |s2cid=5572901 }}</ref>