New Extremeophiles: four examples (Introduction)

by David Turell , Monday, June 05, 2017, 14:29 (2728 days ago) @ David Turell

Each one has great evolutionary tricks to survive:

https://cosmosmagazine.com/biology/four-organisms-living-in-extreme-conditions

"Heated by a subterranean supervolcano, the bubbling hot springs of Yellowstone can exceed 90°C, too hot for ordinary organisms.

"In 1969, while studying the extremophile microbes that do live in Yellowstone’s hotsprings – and give them their colour – Thomas D. Brock and Hudson Freeze of Indiana University discovered Thermus aquaticus. This microbe went on to underpin almost every genetics discovery ever made.

"T. aquaticus contains a heat-tolerant DNA-polymerising enzyme that, once isolated, became a cornerstone of the polymerase chain reaction. PCR is how tiny DNA samples are amplified for analysis – crucial for everything from crime scene analysis to genome reading."

Comment: a special enzyme protects. Enzymes are giant molecules. How did evolution find it by chance?

"When winter arrives in Alaska, the local wood frogs freeze solid. Some seven months later, when spring finally arrives, the thawed-out frogs hop away.

"Freezing once would kill almost any other vertebrate, their organs pierced by ice crystals. Yet as autumn sets in, Alaska’s wood frogs can survive two weeks of night/day freeze-thaw cycles before finally freezing solid. The frogs, like certain other freeze-tolerant fish and insects, produce chemicals that stop ice crystals forming."

Comment: They are known to make an antifreeze molecule.

"Deinococcus radioduransis can survive blasts of gamma radiation 3,000 times the lethal dose for humans.

"In 1999, the US Department of Energy funded research to sequence the bacterium’s genome, in the hope of developing waste-consuming microbes to clean extremely contaminated nuclear sites.

"Surprisingly, D. radioduransis’s DNA has proved just as susceptible to radiation damage as a regular E.coli. The bacterium’s secret is a set of antioxidants that protect its proteins from radiation damage. These proteins can then rapidly repair damaged DNA."

Comment: At the time of early life, radiation on Earth was much more severe than now. That property must come from that ancient time when life originated.

"The microscopic tardigrade, or water bear, can survive heat, cold, desiccation, lack of oxygen and radiation. The tiny animal has even been shown to survive a 10-day trip into space, prompting some to suggest it’s the kind of creature that could live on Mars.
Not so. To survive these conditions the tardigrade puts itself into a form of non-reproductive suspended animation.

"Some extremophiles, however, really do seem equipped for life on the Red Planet. Subterranean micro-organisms found in Earth’s deepest mines and caves seem to have what it takes to survive below the surface on Mars (Cosmos 61, p70). Studying Earth’s extremophiles offers a possible glimpse of what alien life may look like – and where to look for it."

Comment: These examples show how tough life is. We do not know how these living inventions appear, but all the mechanisms are helpful in research.