View source for Biology:Chroococcidiopsis

{{Short description|Genus of bacteria}}
{{Automatic taxobox
| image =
| grandparent_authority = Komárek ''et al.'' 2014<ref name="Komárek">{{cite journal |vauthors=Komárek J, Kaštovský J, Mareš J, Johansen JR | year = 2014 | title = Taxonomic classification of cyanoprokaryotes (cyanobacterial genera) 2014, using a polyphasic approach | url = http://www.preslia.cz/P144Komarek.pdf | journal = Preslia | volume = 86 | pages = 295–335 }}</ref>
| parent_authority = Komárek ''et al.'' 2014<ref name="Komárek"/>
| taxon = Chroococcidiopsis
| authority = Geitler, 1933
| type_species = ''Chroococcopsis gigantea''
| type_species_authority = Geitler, 1933
| subdivision_ranks = Species
| subdivision = 
}}
[[File:Chroococcidiopsis thermalis.jpg|thumb|''Chroococcidiopsis thermalis'' can photsynthesize in far-red light, and might be suitable for future Mars colonists.<ref>[https://www.space.com/40898-low-light-bacteria-mars-colonization.html Weird Low-Light Bacteria Could Potentially Thrive on Mars], Space.com, accessed 6/18/2018</ref> ]]

'''''Chroococcidiopsis''''' is a photosynthetic, coccoidal [[Biology:Bacterium|bacterium]], and the only genus in the order '''Chroococcidiopsidales''' and in the family '''Chroococcidiopsidaceae'''. A diversity of species and cultures exist within the genus,<ref>{{cite journal | vauthors = Cumbers J, Rothschild LJ | title = Salt tolerance and polyphyly in the cyanobacterium Chroococcidiopsis (Pleurocapsales) | journal = Journal of Phycology | volume = 50 | issue = 3 | pages = 472–482 | date = June 2014 | pmid = 26988320 | doi = 10.1111/jpy.12169 | s2cid = 23871779 }}</ref> with a diversity of phenotypes. Some extremophile members of ''Chroococcidiopsis'' are known for their ability to survive harsh environmental conditions, including both high and low temperatures, [[Physics:Ionizing radiation|ionizing radiation]], and high salinity.

==Desiccation resistance==
The ability of ''Chroococcidiopsis'' to resist [[Earth:Desiccation|desiccation]] in arid environments is due in part because it colonizes the underside of translucent rocks. The underside of these rocks provides enough condensed moisture for growth while the rock's translucent nature allows just enough light to reach the organism for photosynthesis to occur.

==Mars colonization==
Due to its resistance to harsh environmental conditions, especially low temperature, low moisture, and radiation tolerance, ''Chroococcidiopsis'' has been thought of as an organism capable of living on [[Astronomy:Mars|Mars]]. Scientists have speculated about the possibility of introducing ''Chroococcidiopsis'' to the Martian environment to aid in the formation of an aerobic environment. In addition to oxygen production, ''Chroococcidiopsis'' could aid in the formation of soil on the Martian surface. On Earth, soil is formed by plant, microbial, and geophysical activity on a mineral substrate. The soil produced by chemical weathering of rocks and oxygen produced by photosynthesis could one day provide the conditions necessary for humans to grow food on Mars, possibly allowing for permanent human civilizations on the planet.<ref>{{cite web|title=Greening of the Red Planet|url=https://science.nasa.gov/science-news/science-at-nasa/2001/ast26jan_1/|publisher=[[Organization:NASA|NASA]]|access-date=2011-03-14|archive-date=2011-03-18|archive-url=https://web.archive.org/web/20110318192200/http://science.nasa.gov/science-news/science-at-nasa/2001/ast26jan_1/|url-status=dead}}</ref><ref>{{cite journal | vauthors = Billi D, Friedmann EI, Hofer KG, Caiola MG, Ocampo-Friedmann R | title = Ionizing-radiation resistance in the desiccation-tolerant cyanobacterium Chroococcidiopsis | journal = Applied and Environmental Microbiology | volume = 66 | issue = 4 | pages = 1489–1492 | date = April 2000 | pmid = 10742231 | pmc = 92012 | doi = 10.1128/aem.66.4.1489-1492.2000 | bibcode = 2000ApEnM..66.1489B }}</ref> On a shorter time scale, cyanobacteria such as ''Chroococcidiopsis'' could be used in closed systems to produce resources for human-occupied outposts on Mars without altering the planet's surface or atmosphere.<ref>{{Cite journal | vauthors = Verseux C, Baqué M, Lehto K, de Vera JP, Rothschild LJ, Billi D |title = Sustainable life support on Mars – the potential roles of cyanobacteria|journal = International Journal of Astrobiology|date = 2015-08-01| volume=15 | issue=1 |issn = 1475-3006|pages = 65–92 |doi = 10.1017/S147355041500021X |bibcode = 2016IJAsB..15...65V|doi-access = free}}</ref>

A space mission called [[Biology:EXPOSE#EXPOSE-R2|EXPOSE-R2]] was launched on 24 July 2014 aboard the Russian [[Engineering:Progress M-24M|Progress M-24M]],<ref name="Gronstal 2014">{{cite news | vauthors = Gronstal AL |url=http://phys.org/news/2014-07-exploring-mars-earth-orbit.html |title=Exploring Mars in low Earth orbit |work=NASA's Astrobiology Magazine |date=31 July 2014 |access-date=2014-08-02 }}</ref> and was attached on 18 August 2014 outside the ISS on the Russian module Zvezda.<ref>{{cite news | vauthors = Kramer M |url=http://www.space.com/26841-spacewalking-cosmonaut-launches-peru-satellite-video.html |title=Russian Cosmonaut Tosses Satellite for Peru During Spacewalk |work=Space.com |date=18 August 2014 |access-date=2014-08-19 }}</ref> The experiment included samples of ''Chroococcidiopsis'' that were exposed to simulated Martian atmosphere, UVC radiation and temperature extremes.<ref name='R2'>{{cite journal | title = The BOSS and BIOMEX space experiments on the EXPOSE-R2 mission: Endurance of the desert cyanobacterium Chroococcidiopsis under simulated space vacuum, Martian atmosphere, UVC radiation and temperature extremes. | journal = Acta Astronautica| date = 20 August 2013 | vauthors = Baqué M, de Vera JP, Rettberg P, Billi D | volume = 91 | pages = 180–186 | doi = 10.1016/j.actaastro.2013.05.015 | issn= 0094-5765 | url = http://elib.dlr.de/83531/ | access-date = 14 January 2014| bibcode = 2013AcAau..91..180B}}</ref> In 2022, the findings of the experiments were published.<ref>{{cite journal | vauthors = Napoli A, Micheletti D, Pindo M, Larger S, Cestaro A, de Vera JP, Billi D | title = Absence of increased genomic variants in the cyanobacterium Chroococcidiopsis exposed to Mars-like conditions outside the space station | journal = Scientific Reports | volume = 12 | issue = 1 | pages = 8437 | date = May 2022 | pmid = 35589950 | pmc = 9120168 | doi = 10.1038/s41598-022-12631-5 | bibcode = 2022NatSR..12.8437N }}</ref>

===UV and desiccation resistance===

[[Earth:Biofilm|Biofilm]]s of ''Chroococcidiopsis'' were exposed to Mars-like [[Physics:Ultraviolet|UV]]-flux and [[Earth:Desiccation|desiccation]] for up to seven years.<ref name="pmid31681194">{{cite journal | vauthors = Mosca C, Rothschild LJ, Napoli A, Ferré F, Pietrosanto M, Fagliarone C, Baqué M, Rabbow E, Rettberg P, Billi D | display-authors = 6 | title = Over-Expression of UV-Damage DNA Repair Genes and Ribonucleic Acid Persistence Contribute to the Resilience of Dried Biofilms of the Desert Cyanobacetrium ''Chroococcidiopsis'' Exposed to Mars-Like UV Flux and Long-Term Desiccation | journal = Frontiers in Microbiology | volume = 10 | issue =  | pages = 2312 | date = 2019 | pmid = 31681194 | pmc = 6798154 | doi = 10.3389/fmicb.2019.02312 | doi-access = free }}</ref>  Biofilms that were either (1) dried or (2) both dried and UV irradiated were able to recover.  When these biofilms were rewetted the [[Biology:Nucleotide excision repair|nucleotide excision repair]] genes encoding UvrA, UvrB and UvrC were over-expressed.  This suggests that [[Biology:Nucleotide excision repair|nucleotide excision repair]] of accumulated [[Biology:DNA damage (naturally occurring)|DNA damage]]s contributed to the recovery.{{citation needed|date=December 2022}}

== See also ==
* ''[[Biology:Deinococcus radiodurans|Deinococcus radiodurans]]''

== References ==
{{Reflist}}

== External links ==
*[http://www.algaebase.org/search/genus/detail/?genus_id=44945 ''Chroococcidiopsis''], [[Biology:AlgaeBase|AlgaeBase]]

{{Extremophile}}
{{Taxonbar|from=Q1088359}}

[[Category:Cyanobacteria]]
[[Category:Cyanobacteria genera]]
[[Category:Extremophiles]]

{{Sourceattribution|Chroococcidiopsis}}