Extremophiles: Life Under Extreme Conditions

Edited by:
  • Koki Horikoshi,
  • Garo Antranikian,
  • William D. Grant,
  • Terry A. Krulwich &
  • Juergen Wiegel
Springer. 4/yr $267, ¥25,000, DM380
The Saracen's Head ‘black smoker’ vent in the Atlantic Ocean floor. Credit: B. MURTON /SCIENCE PHOTO LIBRARY

Why do we suddenly need a journal dedicated to micro-organisms that grow under conditions we humans define as extreme? Micro-organisms that grow in saturated concentrations of salt have been studied for almost 80 years. Pressure- and cold-loving bacteria were identified from the deepest ocean trenches during the Danish Galathea expedition in 1952. For at least 20 years we have known of micro-organisms that grow at temperatures close to 100 °C, alkalinities exceeding pH 10, and acidities near pH 0.

Yet over the past ten years extremophiles have taken on a life of their own, no longer studied as academic peculiarities. High- and low-temperature enzymes from thermal extremophiles are exploited for their many biotechnological applications, while acidophiles assist in the mining of precious metals from complex minerals. Global phylogenetic trees based on nucleic acid sequences indicate that hyperthermophiles are the oldest of extant organisms, holding potential clues to the origin of life on Earth. Their physiologies suggest that they could grow on other solar bodies or survive transit between them. Such controversial ideas, spurred most recently by evidence that the Jovian moon, Europa, may have a liquid-water ocean, are very much part of the study of extremophiles and the emergent field of ‘astrobiology’. Life in extreme environments is in vogue.

Against this backdrop, the creation of a journal dedicated to extremophiles was inevitable. Its appearance is also an acknowledgement of the growing community of researchers dedicated to studying these very exciting organisms from a wide range of disciplinary perspectives. This growth is reflected in the diversity of research papers in the first four issues reporting novel and important new discoveries. The topics range from descriptions of new organisms and physiologies to the characterization of their enzymes and molecular biology. One can also learn that the highest temperature for growth by a pure culture has risen from 110 to 113 °C, that there exist organisms that can oxidize hydrogen gas using ferric-iron as the electron acceptor, and that physiologically diverse heterotrophs exist in the deepest trenches of the ocean.

Overall, the research articles in the first four issues are of high quality. Three issues also offered a very useful review article: I recommend that the editors continue to solicit reviews that keep the community informed of current trends in this rapidly changing field. This attractively produced journal is essential reading for anyone interested in life in extreme environments and its ramifications to other fields of inquiry.