Space X-Philes: Archaea

Should write something here.

Genera containing cryophilic and cryotolerant organisms are marked with an asterisk (*)

Genera containing radiophilic and radioresistant organisms are marked with a dagger (†)

Genera containing cryophilic, cryotolerant, and radioresistant organisms are marked with an asterisk and a dagger (*†)

Genera containing hypobarophilic and hypobarotolerant organisms are marked with two asterisks (**)

Genera containing hypobarophilic, hypobarotolerant, and radioresistant organisms are marked with two asterisks and a dagger (**†)

Genera containing cryohypobarophilic and cryohypobarotolerant organisms are marked with three asterisks (***)

Genera containing cryohypobarophilic, cryohypobarotolerant, and radioresistant organisms are marked with three asterisks and a dagger (***†)

Genera containing xerophilic and xerotolerant organisms are marked with two daggers (††)

Genera containing cryoxerophilic and cryoxerotolerant organisms are marked with an asterisk and two daggers (*††)

Genera containing radioresistant cryoxerophiles and radiocryoxerotolerant organisms are marked with an asterisk and three daggers (*†††)

Genera containing chronotolerant organisms are marked with a double dagger (‡)

Bacteria marked with an three asterisks, three daggers, and a double dagger (***†††‡) are endospore-forming polyextremotolerant organisms. Bacterial endospores tend to give the bacteria capable of producing them polyextremotolerance. Endospores are known for being able to survive extremely high doses of radiation, vacuum dessication, extreme heat and cold, lack of nutrients, and in some cases even the passage of hundreds of millions of years (for example, Bacillus strain 2-9-3 was revived by scientists from 250-million-year-old spores (Vreeland, 2000); for comparison, the first dinosaurs began appearing about 220 MYA — 30 million years later). Although these endospore-forming bacteria can survive a variety of harsh conditions, endospore-formation is not done for reproduction, as with fungal spore formation, but is instead a last-ditch effort to survive conditions the bacterium would not otherwise be able to, which means these critters aren’t true polyextremophiles, because they don’t (necessarily) actually grow better in extreme conditions, and in their endospore form don’t even grow at all.

Cryophilic and cryotolerant organisms are marked with an asterisk (*)

Radiophilic and Radioresistant organisms are marked with a dagger (†)

Radiophilic and Radioresistant cryophiles are marked with an asterisk and a dagger (*†)

Hypobarophilic and hypobarotolerant organisms are marked with two asterisks (**)

Cryohypobarophilic and cryohypobarotolerant organisms are marked with three asterisks (***)

Xerophilic and Xerotolerant organisms are marked with two daggers (††)

Cryoxerophilic and Cryoxerotolerant organisms are marked with an asterisk and two daggers (*††)

Radioresistant cryoxerophiles and radiocryoxerotolerant organisms are marked with an asterisk and three daggers (*†††)

Chronotolerant organisms are marked with a double dagger (‡)

Bacteria marked with an three asterisks, three daggers, and a double dagger (***†††‡) are endospore-forming polyextremotolerant organisms. Bacterial endospores tend to give the bacteria capable of producing them polyextremotolerance. Endospores are known for being able to survive extremely high doses of radiation, vacuum dessication, extreme heat and cold, lack of nutrients, and in some cases even the passage of hundreds of millions of years (for example, Bacillus strain 2-9-3 was revived by scientists from 250-million-year-old spores (Vreeland, 2000); for comparison, the first dinosaurs began appearing about 220 MYA — 30 million years later). Although these endospore-forming bacteria can survive a variety of harsh conditions, endospore-formation is not done for reproduction, as with fungal spore formation, but is instead a last-ditch effort to survive conditions the bacterium would not otherwise be able to, which means these critters aren’t true polyextremophiles, because they don’t (necessarily) actually grow better in extreme conditions, and in their endospore form don’t even grow at all.

Schuerger & Nicholson, 2016.
http://doi.org/10.1089/ast.2016.1587

Nicholson &al., 2013.
https://doi.org/10.1073/pnas.1209793110