有一句至理名言大意是说没有人是绝对孤独的，然而很显然，有些细菌却真能做到这一点。
据美国《科学》杂志在线新闻报道，科学家从南非深达2800千米的Mponeng金矿中挖掘出5000多公升液体，这些液体中只生活着一种生物—— 一种名为Candidatus Desulforudis audaxviator的细菌（如图）。这种孤独的生物完全自给自足，这是因为它具有一套能够养活自己的生态系统，可以完成全部的功能，包括处理碳和氮。然而这种细菌却很难在地面上生存——它完全是在无氧的环境中进化的，因此地面的空气会让它们丧命。（生物谷Bioon.com）
生物谷推荐原始出处：
Science 10 October 2008:DOI: 10.1126/science.1155495
Environmental Genomics Reveals a Single-Species Ecosystem Deep Within Earth
Dylan Chivian,1,2* Eoin L. Brodie,2,3 Eric J. Alm,2,4 David E. Culley,5 Paramvir S. Dehal,1,2 Todd Z. DeSantis,2,3 Thomas M. Gihring,6 Alla Lapidus,7 Li-Hung Lin,8 Stephen R. Lowry,7 Duane P. Moser,9 Paul M. Richardson,7 Gordon Southam,10 Greg Wanger,10 Lisa M. Pratt,11,12 Gary L. Andersen,2,3 Terry C. Hazen,2,3,12 Fred J. Brockman,13 Adam P. Arkin,1,2,14 Tullis C. Onstott12,15
DNA from low-biodiversity fracture water collected at 2.8-kilometer depth in a South African gold mine was sequenced and assembled into a single, complete genome. This bacterium, Candidatus Desulforudis audaxviator, composes >99.9% of the microorganisms inhabiting the fluid phase of this particular fracture. Its genome indicates a motile, sporulating, sulfate-reducing, chemoautotrophic thermophile that can fix its own nitrogen and carbon by using machinery shared with archaea. Candidatus Desulforudis audaxviator is capable of an independent life-style well suited to long-term isolation from the photosphere deep within Earth's crust and offers an example of a natural ecosystem that appears to have its biological component entirely encoded within a single genome.
1 Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
2 Virtual Institute for Microbial Stress and Survival, Berkeley, CA 94720, USA.
3 Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
4 Departments of Biological and Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
5 Energy and Efficiency Technology Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
6 Department of Oceanography, Florida State University, Tallahassee, FL 32306, USA.
7 Genomic Technology Program, U.S. Department of Energy (DOE) Joint Genomics Institute, Berkeley, CA 94598, USA.
8 Department of Geosciences, National Taiwan University, Taipei 106, Taiwan.
9 Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, NV 89119, USA.
10 Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada
11 Department of Geological Sciences, Indiana University, Bloomington, IN 47405, USA.
12 Indiana Princeton Tennessee Astrobiology Initiative (IPTAI), NASA Astrobiology Institute, Bloomington, IN 47405, USA.
13 Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
14 Department of Bioengineering, University of California, Berkeley, CA 94720, USA.
15 Department of Geosciences, Princeton University, Princeton, NJ 08544, USA.
