"Miracle" Microbes Thrive at Earth's Extremes

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"Genomics has made a very significant contribution to the modus operandi of all extremophile fields," Robb said.

Genomics are the primary focus for the upcoming extremophile conference. Participants will also focus on a class of microbes known as the archaea, which literally means "ancient." Archaea differ enough genetically from bacteria to warrant their own branch on the evolutionary tree of life.

Many archaea are extremophiles. Scientists believe archaea resemble the earliest forms of life on Earth.

Archaea split off from bacteria some four billion years ago. Ancestors that split from archaea evolved into eukaryotes—life-forms, including humans, whose cells have nuclei.

Archaea are more similar to eukaryotes than bacteria, but much simpler and easier to analyze than eukaryotes. Their study, as a result, has made important contributions to understanding how eukaryote DNA is repaired and copied, Robb said.

Such insights may lead to better treatments for diseases like cancer, since progression of the disease relies on DNA replication and cell division on a continual basis.

Archaea are also providing scientists insight to the process of how proteins are built inside cells. "Some outstanding discoveries have been made," including pyrrolysine, the 22nd amino acid known to science, Robb said.

Amino acids are the key building blocks of proteins. Scientists once thought only 21 amino acids existed. But in 2002 a group of researchers discovered a new amino acid, pyrrolysine, while studying extremophiles that produce methane or natural gas as a by-product of energy generation. The find indicated that the genetic code is more flexible than originally thought.

Hyperthermophiles

One of the more eagerly anticipated talks at the upcoming conference will be given by Karl Stetter. A microbiologist at the University of Regensburg in Germany, Stetter is recognized as one of the world's greatest extremophile hunters.

"I will concentrate on hyperthermophiles, which are the most extreme of all extremophiles and which represent my field of interest for 25 years," he said.

According to Stetter, hyperthermophiles are unusually shaped archaea. Some look like snakes. Others resemble yeastlike spheres and cobwebs. All require extreme heat for their survival.

Stetter will also talk about nanoarchaea, which he describes as "a novel kingdom of dwarfy archaea," and the first genome sequenced from the group. "The Nanoarchaea appear to be very ancient symbionts," he said, referring to life forms that live symbiotically with others, "most likely existing since the earliest days of life."

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