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Deep biosphere
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Biogeoscientists show evidence of 90 billion tons of microbial organismsexpressed in terms of carbon massliving in the deep biosphere, in a research article published online by Nature, July 20, 2008. This tonnage corresponds to about one-tenth of the amount of carbon stored globally in tropical rainforests. The authors: Kai-Uwe Hinrichs and Julius Lipp of the Center for Marine Environmental Sciences (MARUM) at University of Bremen, Germany; and Fumio Inagaki and Yuki Morono of the Kochi Institute for Core Sample Research at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) concluded that about 87 percent of the deep biosphere consists of Archaea.

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Extreme life-forms
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While scientists find ever more planets around other stars and contemplate missions to probe the far reaches of our own solar system, researchers are looking to the extremes of the Earth for clues about what kind of organisms could exist in the brutal conditions elsewhere.
There's hardly a niche on Earth that hasn't been colonised. Life can be found in scalding, acidic hot pools, in the driest deserts, and in the dark, crushing depths of the ocean. It has even found a toehold in the frigid polar regions and in toxic dumps.

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RE: extreme lifeform
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A team of Penn State scientists has discovered a new ultra-small species of bacteria that has survived for more than 120,000 years within the ice of a Greenland glacier at a depth of nearly two miles. The microorganism's ability to persist in this low-temperature, high-pressure, reduced-oxygen and nutrient-poor habitat makes it particularly useful for studying how life, in general, can survive in a variety of extreme environments on Earth and possibly elsewhere in the solar system.

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Microbes have created a home in 111-million-year-old rock buried 1.6 kilometres below the sea floor, researchers have found.
The discovery, published today in Science, beats the old record 842 metres below the sea floor but may not stand for long. Some experts think that microbes could potentially set up home as far down as 5 kilometres below the sea floor.

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Study maps life in extreme environments
A team of biologists have developed a model mapping the control circuit governing a whole free living organism. This is an important milestone for the new field of systems biology and will allow the researchers to model how the organism adapts over time in response to its environment. This study marks the first time researchers have accurately predicted a cells dynamics at the genome scale (for most of the thousands of components in the cell). The findings, which are based on a study of Halobacterium salinarum, a free-living microbe that lives in hyper-extreme environments, appear in the latest issue of the journal Cell.

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 Tough Enough for Mars, but Deinococcus is from Earth
Results of a recent study titled Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks, will be published in the Sept. 26 edition of PLoS ONE.

Bacteria of the genus Deinococcus are extremely resistant to ionising radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at its optimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterised genes that might participate in DNA repair and contribute to resistance; and strengthen the case for a role in survival of systems involved in manganese and iron homeostasis.

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