O Mysterium tremendum continua misterioso

quinta-feira, abril 02, 2009




Amino Acids and the Asymmetry of Life
by Meierhenrich, Uwe





“How did life originate on Earth and why were specific amino acids selected for its architecture?” This question of high public and interdisciplinary scientific interest is the central theme of a new book written by professor Uwe Meierhenrich from the University of Nice. In 2002, his international research team realized that amino acids are not only required for the development of living organisms on Earth, but that large amounts of amino acids are constantly synthesized in interstellar clouds in space. This research result was published in Nature and attracted considerable attention worldwide. Today, the question “did life as we know it find its molecular roots in space?” is asked in various scientific domains. Did the molecular building blocks of biological organisms really originate from interstellar clouds and did these building blocks trickle on the early Earth that acted in a way as a Petri dish to trigger the evolution of life? And if the answer to this question is “yes”, is there life on other planets, since numerous exoplanets had been discovered recently?

In order to answer this question, the asymmetry of amino acids was studied in more detail. It is well-known that the parity between right-handed amino acids and their left-handed mirror-images was violated for the origin of life. The equilibrium was shifted in favor of left-handed amino acids. Nowadays, proteins of living organisms exclusively use left-handed amino acids as monomer building blocks. This information is used to decipher crucial aspects of the origin of life. Experiments onboard of the space missions Rosetta and ExoMars but also lab experiments on the symmetry-breaking of biomolecules focus on the handedness of prebiotic molecules and aim to clarify our understanding of the origin of life on Earth.

Written in an intoxicating style, this book describes how the basic building blocks of life, the amino acids, formed. After a comprehensible introduction into stereochemistry, the author addresses the inherent property of amino acids in living organisms, namely the preference for left-handedness. What was the cause for violation of parity of amino acids in the emergence of life on Earth? All the fascinating models proposed by physicists, chemists and biologist are vividly presented including the scientific conflicts. The author describes the attempt to verify any of those models with the chirality module of the ROSETTA mission, a probe built and launched with the mission to land on a comet and analyse whether there are chiral organic compounds that could have been brought to the Earth by cometary impacts. A truly interdisciplinary astrobiology book, “Amino Acids and the Asymmetry of Life”, will fascinate students, researchers and all readers with backgrounds in natural sciences. With a foreword by Henri B. Kagan.

October 27, 2008

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Life in the Universe. Expectations and Constraints.

Dirk Schultze-Makuch and Louis N. Irwin. Springer, 2004

Astrobiologists are often asked, “Why can’t life be based on silicon, rather than carbon?” And “What are the chances that life might exist in methane oceans on Titan?” This book is a primer that can help answer such questions, or at least provide a perspective from which to speculate. The authors’ goal is to review our current understanding of the origin and history of life on the Earth, then extrapolate to possible variations in extraterrestrial settings.

The book begins with an attempt to define life. The authors consider and reject earlier definitions, then propose their own, which is based on three primary characteristics of life: “Life is: 1) composed of bounded microenvironments in thermodynamic disequilibrium with their external environment, 2) capable of transforming energy and the environment to maintain a low energy state, and 3) capable of information encoding and transmission.”

The authors continue with chapters on the history of life on the Earth, energy sources of life, and building blocks of life. They discuss not just the standard textbook information, but go on to extrapolate to unusual environments that might exist on other planets. For instance, in a chapter on energy sources they consider the usual light and chemical energy, but then go on to magnetic fields, pressure gradients and spin configurations that might provide energy on other planetary settings. In a chapter on the building blocks of life, they contrast carbon and silicon chemistry and provide a thorough discussion of how silicon compounds such as silanes, silicones and silicates might be incorporated into exotic forms of life. In a chapter on solvents, liquid water is compared to ammonia, HCN, HF, H2S, SO2, hydrazine and non-polar solvents. The book ends with chapters on habitats, exotic forms of life and biosignatures.

The book is concise, with nine chapters in 170 pages, and lacks an index. A typical chapter is illustrated with line drawings, photographs and a few color images scattered through the text. For readers who would like a brief, knowledgeable exploration of potential distribution of life in the universe, and chemical and physical constraints imposed by a definition unconstrained by what we think we know about life on the Earth, this book is worth reading. Most readers will have their curiosity satisfied and their horizons expanded.

Reviewed by David Deamer, February 2005

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Josef Elster announces the publication of Life in the Frozen State, edited by Barry J. Fuller, Nick Lane and Erica E. Benson. More information can be found at http://pages.britishlibrary.net/b.fuller/index.htm

“This book is the first major text on cryobiology in the genomic era. The chapters encompass disciplines ranging from mathematical modelling and biophysics, to the molecular biology of stress gene expression and ecological adaptations in extreme environments, to biotechnology and the conservation of natural resources and clinical banking of cells, tissues and organs.

“Written accessibly by leading world experts, the book melds a cross-disciplinary platform of knowledge in cryobiology to foster new thinking and collaborations. It will prove an invaluable resource for students and researchers in the field, as well as anyone working in professions that touch on the preservation and destruction of life in the frozen state.”

Publisher: CRC Press UK
Format: 7 x 10 Hard Cover, 540pp
Price: $89.95 / £54.99

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Professor Joseph Seckbach announces that the book series COLE (in which he serves as the chief editor) expects to publish 3 new volumes this year. To obtain further information about this series, please visit the website.

The first new volume, entitled “ORIGINS: GENESIS, EVOLUTION AND DIVERSITY OF LIFE” will appear at end of June (2004). The next volume, “LIFE IN THE UNIVERSE” (the proceedings of Trieste-2003 conference) is scheduled for August, and the third book, entitled: “NEW AVENUES IN BIOINFORMATICS” should be available in September (2004).

Prof. Seckbach is also preparing a new book entitled: ”ADAPTATION OF LIFE AT HIGH SALT CONCENTRATION: ARCHAEA, BACTERIA and EUKARYA.” This book will publish the proceedings of the Halophiles-2004 conference scheduled to take place in Ljubljana (Slovenia) in September, 2004. Prof. Seckbach invites suggestions from ISSOL members who would like to contribute to this and future books related to the origin of life.

-David Deamer, 8 June 2004

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Jim Strick announces that the official history of exobiology and the astrobiology under NASA, up through 2003, is being published by Rutgers U. Press in August 2004. The book describes the history of exo- and astrobiology and includes interviews with most of the primary participants. It can be purchases from Amazon.com.

THE LIVING UNIVERSE
NASA and the Development of Astrobiology
STEVEN J. DICK AND JAMES E. STRICK

The Living Universe is a comprehensive, historically nuanced study of the formation of the new scientific discipline of exobiology and its transformation into astrobiology. The authors explain how research on the origin of life became wedded to the search for life on other planets. Many scientific breakthroughs of the last forty years were either directly supported or indirectly spun off from NASA’s exobiology program, including cell symbiosis, the discovery of the Archaea, and the theories of Nuclear Winter and the asteroid extinction of the dinosaurs.

Exobiology and astrobiology have generated public fascination, enormous public relations benefits for NASA, and–the flip side of the coin–some of the most heated political wrangling ever seen in government science funding. Dick and Strick provide a riveting overview of the search for life throughout the universe, with all of the Earthly complexities of a science-in-the making and the imperfect humans called scientists. Their book is the first to include oral history interviews with all of the primary participants from 1953 to the present. It will appeal to biologists, historians and philosophers of science, planetary scientists (including geologists), and an educated general readership interested in the investigation of life on other planets.

Steven J. Dick is chief historian of NASA and associate editor of the International Journal of Astrobiology. Among his books are Sky and Ocean Joined: The U.S. Naval Observatory, 1830-2000, and Life on Other Worlds, which has been translated into four languages. James E. Strick is the author of Sparks of Life: Darwinism and the Victorian Debates over Spontaneous Generation. He is an assistant professor in the program in science, technology and society at Franklin and Marshall College.

-David Deamer, 8 June 2004

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Radu Popa. Between Necessity and Probability: 2004. Searching for the definition and origin of life.
Springer 252 pp, 58 figures b/w

Radu Popa is one of the rare scientists who attempt to see the big picture, and this book is the result. Popa brings an unusual background to his writing. He has investigated sealed cave ecosystems in Romania, and spent post-doctoral years in the astrobiology program at the Jet Propulsion Laboratory in Pasadena. He also brings a sense of European scholarship to his writing, and a remarkable breadth of interests.
Some of the flavor of this book is imparted by a quote from Marcus Aurelius on the first page: “Everything we hear is an opinion, not the fact. Everything we see is a perspective, not the truth.” I take this as a caveat from the author, that readers should maintain a certain level of appropriate skepticism as we follow his discussion of ideas regarding the origin of life. To give a sense of the book’s contents, it is worth listing the chapter titles:

The early history of bioenergy.
Origin of cell boundaries and metabolism
Origin of specificity. The order, complexity and diversity of life.
The origin of handedness
The early history of Bio-Information
The purpose-Like nature of life.
Assembling the early puzzle of life.
The material-independent signatures of life. Forensic tools of astrobiology.
Appendix A. Models and theories of life.
Appendix B. Chronology of definitions and interpretations of life.
Appendix C. Dictionary

The titles immediately suggest that the author brings his own approach to the question of life’s origin. This is not a light-hearted treatise. Instead, the book is a balanced, succinct and scholarly effort growing out of the author’s experience in exobiology and astrobiology. The author is even-handed, covering without prejudice most of the main concepts that have been put forward to explain the origin of life. Part of the value of the book is that virtually everyone will discover publications and concepts they did not know about. The author has clearly done his homework.

Although the author discusses the contributions of many predecessors in the field, there are also some genuinely novel concepts expressed in the book. Some of these are philosophical, such as the chapter entitled The Purpose-Like Nature of Life. Others suggest new experimental approaches. The main text is followed by a series of appendices which also contain useful information. For instance, the author cites 572 papers ranging from1855 to 2002, with 40 total cited in 2002 alone. Ten models and theories of life are summarized in Appendix A, and a glossary/dictionary helps the uninitiated to understand the peculiar scientific dialect that has emerged in the study of life’s beginnings.

-David Deamer, 21 May 2004

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How Life Began by William Day.
Published by Marvin Solit, Foundation For New Directions
Paperback, 232 pages
Publisher’s Price: $21.95

To see the Preface, publisher’s description and ordering information go to http://www.Fnd.org

Since writing Genesis of Planet Earth (Yale University Press, 1984) the author has focused on the chemical processes that led to life’s origin, and the order in which they appeared. In HOW LIFE BEGAN, Day presents his hypothesis on how organic chemistry got started, and offers a step by step formulation of the metabolic and genetic systems that followed.

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The Life and Death of Planet Earth by Peter Ward and Donald Brownlee.
Published by Times Books
hardcover, 240 pages
Publisher’s Price: $25.00

To see the descriptions, reviews, excerpts, and ordering information go to http://www.writtenvoices.com

The Life and Death of Planet Earth discusses the latest findings about the histories of planets and applies this knowledge to the earth. Including what scientists know about the earth’s geological and biological past present and future, Brownlee and Ward describe a colorful and often shocking series of changes our earth will undergo in the coming millennia until it’s inevitable end.

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