''Chroococcidiopsis'' is a

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

, coccoidal

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

, and the only genus in the order Chroococcidiopsidales and in the family Chroococcidiopsidaceae. A diversity of species and cultures exist within the genus, with a diversity of phenotypes. Some

extremophile An extremophile () is an organism that is able to live (or in some cases thrive) in extreme environments, i.e., environments with conditions approaching or stretching the limits of what known life can adapt to, such as extreme temperature, press ...

members of ''Chroococcidiopsis'' are known for their ability to survive harsh environmental conditions, including both high and low temperatures,

ionizing radiation Ionizing (ionising) radiation, including Radioactive decay, nuclear radiation, consists of subatomic particles or electromagnetic waves that have enough energy per individual photon or particle to ionization, ionize atoms or molecules by detaching ...

, and high salinity. ''Chroococcidiopsis'' are able to survive in a dormant state for at least 13 million years, with the ability to reactivate after this time.

Desiccation resistance

The ability of ''Chroococcidiopsis'' to resist

desiccation Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. The ...

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. A 2023 study found ''Chroococcidiopsis'' is able to survive for long periods in a desiccated state on solar panels, under irradiated conditions. The samples were able to be genetically altered, proving potential future uses, but no specific task was coded into the samples used.

UV and desiccation resistance

Biofilm A biofilm is a Syntrophy, syntrophic Microbial consortium, community of microorganisms in which cell (biology), cells cell adhesion, stick to each other and often also to a surface. These adherent cells become embedded within a slimy ext ...

s of ''Chroococcidiopsis'' were exposed to Mars-like UV-flux and

for up to seven years. Biofilms that were either (1) dried or (2) both dried and UV irradiated were able to recover. When these biofilms were rewetted the

nucleotide excision repair Nucleotide excision repair is a DNA repair mechanism. DNA damage occurs constantly because of chemicals (e.g. Intercalation (biochemistry), intercalating agents), radiation and other mutagens. Three excision repair pathways exist to repair single ...

genes encoding UvrA, UvrB and UvrC were over-expressed. This suggests that

of accumulated

DNA damage DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. A weakened capacity for DNA repair is a risk factor for the development of cancer. DNA is constantly modified ...

s contributed to the recovery.

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

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

. 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. 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. A space mission called EXPOSE-R2 was launched on 24 July 2014 aboard the Russian

Progress M-24M Progress M-24M (), identified by NASA as Progress 56P, is a Progress spacecraft used by Roskosmos to resupply the International Space Station (ISS) during 2014. Progress M-24M was launched on a six-hours rendezvous profile towards the ISS. The ...

, and was attached on 18 August 2014 outside the ISS on the Russian module Zvezda. The experiment included samples of ''Chroococcidiopsis'' that were exposed to simulated Martian atmosphere, UVC radiation and temperature extremes. In 2022, the findings of the experiments were published.

References

External links

''Chroococcidiopsis''

AlgaeBase AlgaeBase is a global species database of information on all groups of algae, both seaweed, marine and freshwater algae, freshwater, as well as sea-grass. History AlgaeBase began in March 1996, founded by Michael D. Guiry, Michael Guiry. Text ...

{{Taxonbar, from=Q1088359 Cyanobacteria Cyanobacteria genera Space-flown life Extremophiles

Desiccation resistance

UV and desiccation resistance

Mars colonization

See also

References

External links