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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 28, 6 July 2004
Marsbugs: The Electronic Astrobiology Newsletter
Volume 11, Number 28, 6 July 2004
Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, Arkansas 72503-2317, USA.
Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, except for specific articles, in which instance copyright exists with the author/authors. Opinions expressed in this newsletter are those of the authors, and are not necessarily endorsed by the editor or by Lyon College. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available at The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor.
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 28, 6 July 2004
Articles and News
Page 1BASIC RNA ENZYME RESEARCH PROMISES SINGLE-MOLECULE BIOSENSORS
University of Michigan release
Page 2HUMAN CONSUMPTION OF NET PRIMARY PRODUCTION
NASA Earth Observatory release
Page 2THE GOING GETS TOUGH FOR LIFE IN OTHER SOLAR SYSTEMS
Royal Astronomical Society (UK) release
Page 4LIFE IN A DUSTY FORMALDEHYDE JAR
Based on an OSU report
Page 5101 AMAZING EARTH FACTS
By Robert Roy Britt
Announcements
Page 5EUROPEAN MARS AND PLANETARY CONVENTION
By Horia-Nicolai Teodorescu
Page 5PROGRAM FOR THE OXYGEN IN THE TERRESTRIAL PLANETS WORKSHOP
Lunar and Planetary Institute release
Page 6NIAC PHASE II PROJECTS SELECTED
From NASA's Institute for Advanced Concepts
Page 6EARTH SYSTEM PROCESSES 2 (ESP2) MEETING ANNOUNCEMENT
By Lee Lump
Page 6NEW ADDITIONS TO THE ASTROBIOLOGY INDEX
By David J. Thomas
Mission Reports
Page 6CASSINI UPDATES
NASA and ESA releases
Page 12MARS EXPLORATION ROVERS: KIDS, ROVERS AND MARS
NASA/JPL release
Page 13MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 14MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Page 14ROSETTA UPDATE #18: TESTING AVAILABILITY OF MGA-S ANTENNA
ESA release
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 28, 6 July 2004
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 28, 6 July 2004
BASIC RNA ENZYME RESEARCH PROMISES SINGLE-MOLECULE BIOSENSORS
University of Michigan release
29 June 2004
Research aimed at teasing apart the workings of RNA enzymes eventually may lead to ways of monitoring fat metabolism and might even assist in the search for signs of life on Mars, according to University of Michigan researcher Nils Walter. His latest work was published online in the Proceedings of the National Academy of Sciences June 24.
Walter and associates at U-M and colleague Xiaowei Zhuang and associates at Harvard University, use techniques that allow them to study single molecules of RNA enzymes, also known as ribozymes. Like the more familiar protein enzymes, RNA enzymes accelerate chemical reactions inside cells. Researchers want to learn how changes in ribozyme molecules affect their activity, both to better understand how evolution has shaped ribozymes to carry out their duties and to find ways of manipulating them for useful purposes.
In the recent research, Walter's group combined a technique called single-molecule fluorescence resonance energy transfer (FRET) with mathematical simulations to study a ribozyme involved in the replication of a tobacco-infecting virus. Just as a protein enzyme is not a static structure, a ribozyme also changes shape, cycling back and forth between its compact, catalytically active form and its inactive, extended form. Single-molecule FRET allowed the researchers to directly observe and measure how quickly the ribozyme switched forms and how these rates changed when various parts of the molecule were altered.
With the addition of mathematical simulations, the researchers also could investigate how changing parts of the ribozyme molecule affected its ability to catalyze chemical reactions. They were surprised to find that modifications they made anywhere on the molecule—even far from the site where the chemical reaction occurs—affected the rate of catalysis.
That's much like what is known to happen in protein enzymes, but until now there was no evidence that ribozymes behaved similarly, said Walter, a Dow Corning Assistant Professor of Chemistry.
"It's been known for a couple of years now that if you modify something on a protein enzyme that you think is pretty far away from the catalytic core—where the chemistry is actually happening—you see that the chemistry is affected directly," Walter said. "This has led to the idea that there is a network of motions that make a protein enzyme act as a whole. We are proposing for the first time that this also happens with RNA enzymes."
Getting a grasp on how ribozymes work is important for answering fundamental questions of biology, Walter said, but the work may also lead to practical applications. In particular, Walter and U-M collaborators Robert T. Kennedy, the Hobart H. Willard Professor of Chemistry and Pharmacology, and Jens-Christian Meiners, assistant professor of physics and assistant research scientist, Biophysics Research Division, are exploring their use as biosensors. The idea is to selectively turn on a ribozyme molecule that catalyzes a reaction to generate a product that gives off a specific fluorescent signal only when a particular type of molecule binds.
"When you can do that on the single-molecule level, as we can do now, then you have the smallest possible biosensor," Walter said. Such sensors could be designed to detect important hormones like leptin, which is involved in fat metabolism. With such a tool, "you could detect how a single cell makes leptin and ask how much the cell makes when theenvironment changes," he said.
In another project, funded by NASA, the researchers hope to develop abiosensor that could be sent to Mars to snoop around for amino acids orother signs that life might once have existed on the planet.
"These projects are still in the development stage," Walter said. "But thetechnology we are developing here to ask some fundamental biologicalquestions will ultimately help us learn how to design biological sensorswith many potential applications."
Related links
Nils Walter
PNAS paper, "Single-molecule enzymology of RNA: Essential functionalgroups impact catalysis from a distance"
RNA enzymes
Fluorescence resonance energy transfer
Contact:
Nancy Ross-Flanigan
Phone:734-647-1853
E-mail:
Read the original news release at
An additional article on this subject is available at
HUMAN CONSUMPTION OF NET PRIMARY PRODUCTION
NASA Earth Observatory release
29 June 2004
NASA images courtesy Marc Imhoff and Lahouari Bounoua at Goddard Space Flight Center.
In an effort to gauge human impact on ecosystems, scientists at NASA and the World Wildlife Fund recently published estimates of how much of Earth's plant life humans consume for food, fiber, wood, and fuel. By understanding patterns of consumption, and how the planetary supply of plant life relates to the demand for it, these results may enable better management of Earth's rich biological heritage. Understanding the patterns of supply and demand is critical for identifying areas of severe human impact on ecosystems and planning for sustainable future growth. The details of this study appear in the June 24, 2004, issue of Nature magazine.
Using data collected between 1982-98 by the NOAA Advanced Very High Resolution Radiometer, the researchers calculated the total amount of carbon absorbed by land plants each year and fixed in plant structures—a measure referred to as "Net Primary Production," or NPP. Then the researchers used computer models to estimate how much of Earth's land-based net primary productivity is consumed by humans. They found that humans require 20 percent of the NPP generated on land every year. Of course, consumption varies greatly by region and is influenced by three factors: population, per capita consumption, and technology. For more details, please see the NASA press release, entitled NASA Scientists Get Global Fix on Food, Wood, & Fiber Use (
The maps above show human appropriation of land-based net primary production. The shades in the top map represent billions of grams of carbon consumed each year for a given location on Earth. Tan shows low values while dark brown shows high values. The bottom map represents the percentage of NPP consumed by humans each year for a given location. The map reveals that in certain places—such as the northeastern United States, much of Europe, the Middle East, as well as Southern and Eastern Asia—humans consume far more of plants' net primary productivity than is locally produced. Therefore, people living in these areas must import food, fiber, wood, and fuel in order to meet their demands for products derived from plants.
Read the original article at
An additional article on this subject is available at
THE GOING GETS TOUGH FOR LIFE IN OTHER SOLAR SYSTEMS
Royal Astronomical Society (UK) release
30 June 2004
Though the star Tau Ceti is similar to the Sun, any planets it has are unlikely to be havens for life, say a team of UK astronomers. Using submillimeter images of the disk of material surrounding Tau Ceti, they found that it must contain more than ten times as many comets and asteroids than there are in the Solar System. With so many more space rocks hurtling around the star, devastating collisions of the sort that could lead to the destruction of life would be much more likely in the Tau Ceti system than in our own planetary system.
Publication of the result in Monthly Notices of the Royal Astronomical Society coincides with an exhibit "Hunting for Planets in Stardust" at the Royal Society Summer Exhibition by the same science team from the UK Astronomy Technology Centre in Edinburgh and the University of Saint Andrews.
Tau Ceti, only 12 light years away, is the nearest sun-like star and is easily visible without a telescope. It is the first star to be found to have a disk of dust and comets around it similar in size and shape to the disk of comets and asteroids that orbits the Sun. But the similarity ends there explains Jane Greaves, Royal Astronomical Society Norman Lockyer Fellow and lead scientist: "Tau Ceti has more than ten times the number of comets and asteroids that there are in our Solar System. We don't yet know whether there are any planets orbiting Tau Ceti, but if there are, it is likely that they will experience constant bombardment from asteroids of the kind that is believed to have wiped out the dinosaurs. It is likely that with so many large impacts life would not have the opportunity to evolve."
The discovery means that scientists are going to have to rethink where they look for civilizations outside our Solar System. Jane Greaves continues, "We will have to look for stars which are even more like the Sun, in other words, ones which have only a small number of comets and asteroids. It may be that hostile systems like Tau Ceti are just as common as suitable ones like the Sun."
Artist's impression: For any planets orbiting Tau Ceti, the skies will be criss-crossed with comets and meteors will frequently strike the surface. Image credit: David Hardy.
The reason for the larger number of comets is not fully understood explains Mark Wyatt, another member of the team: "It could be that the Sun passed relatively close to another star at some point in its history and that the close encounter stripped most of the comets and asteroids from around the Sun."
The new results are based on observations taken with the world's most sensitive submillimeter camera, SCUBA. The camera, built by the Royal Observatory, Edinburgh, is operated on the James Clerk Maxwell Telescope in Hawaii. The SCUBA image shows a disk of very cold dust (-210°C) in orbit around the star. The dust is produced by collisions between larger comets and asteroids that break them down into smaller and smaller pieces.
Image of the disc of dust particles around the star Tau Ceti, taken with the submillimeter-wavelength camera SCUBA. The false colors show the brightness of the disc. Its diameter is slightly larger than the Solar System. Image credit: James Clerk Maxwell Telescope.
The James Clerk Maxwell Telescope (JCMT) was used to take the image of the Tau Ceti dust disk. It is the world's largest single-dish submillimeter telescope. It collects faint submillimeter signals with its 15 meter diameter dish. It is situated near the summit of Mauna Kea on the Big Island of Hawaii, at an altitude of approximately 4000 meters (14000 feet) above sea level. Image credit: Nik Szymanek.
Notes
- Royal Society Summer Exhibition. The Royal Society Summer Exhibition runs from 5 to 8 July and is open to the general public on Monday 5 July, 6:00PM- 9:00PM; Tuesday 6 July, 11:00 AM- 4.30 PM; Wednesday 7 and Thursday 8 July, 10:00AM- 4.30 PM.
- Observing Tau Ceti. Tau Ceti is in the constellation Cetus. Although it is visible without a telescope, at this time of year it rises in the Southeast at about 3:00AM, just before the Sun, so is very hard to spot.
- The James Clerk Maxwell Telescope (JCMT). The JCMT is the world's largest single-dish submillimeter telescope. It is situated near the summit of Mauna Kea on the Big Island of Hawaii, at an altitude of approximately 4000 meters (14000 feet) above sea level. It is operated by the Joint Astronomy Centre, on behalf of the UK Particle Physics and Astronomy Research Council, the Canadian National Research Council, and the Netherlands Organization for Scientific Research.
- SCUBA. SCUBA (the Submillimeter Common-User Bolometer Array) is the world's most powerful submillimeter camera. It is attached to the James Clerk Maxwell Telescope, and contains sensitive detectors called bolometers, which are cooled to 60 milliKelvin, 0.06 degrees above absolute zero (60 milliKelvin is about -273.1 degrees Celsius or -459.6 degrees Fahrenheit). SCUBA was built in the UK by the Royal Observatory, Edinburgh, at what is now the UK Astronomy Technology Centre.
- Images are available from
Contacts:
Dr. Jane Greaves, Astronomer, University of Saint Andrew
Phone: (+44) (0)7745 127391
E-mail:
Peter Barratt, Head of Communications, PPARC
Phone: (+44) (0)1793 442025
E-mail:
Eleanor Gilchrist, Public Relations Officer, Royal Observatory Edinburgh Phone (mobile): (+44) (0)771 873 6971
Phone (office): (+44) (0)131 668 8379
E-mail:
Douglas Pierce Price, James Clerk Maxwell Telescope
Phone: (+1) 808 969 6524
E-mail:
Additional articles on this subject are available at:
LIFE IN A DUSTY FORMALDEHYDE JAR
Based on an OSU report
From Astrobiology Magazine
3 July 2004
Scientists at Ohio State University have found that a formaldehyde-based chemical is 100 times more common in parts of our galaxy than can be explained. The finding could change ideas about how organic molecules form in the universe, and how those molecules' critical interaction with dust causes stars and planets to form. The scientists compared the results of experiments from an international team of chemists to telescopic measurements of the amount of methyl formate—a product of alcohol and formaldehyde—in the swirling dust clouds that dot our Milky Way galaxy. On Earth, methyl formate is commonly used as an insecticide.
Dust grain or IDP, interstellar dust particle. One sugar-related building block of life, called ribose, is simply five molecules of formaldehyde strung together, and formaldehyde is easy to make where there is carbon dioxide and light. Image credit: UWSTL, NASA Hubble.
Based on telescope data, if the gaseous methyl formate condensed into liquid form, a typical dust cloud would contain a thousand trillion trillion gallons of the chemical. Interstellar dust clouds contain the chemical seeds of new stars and planetary systems, explained Eric Herbst, Distinguished Professor of Mathematical and Physical Sciences at Ohio State. Most people are probably familiar with the dust cloud known as the Horsehead Nebula in the constellation Orion.
While scientists have long known that hydrogen is the most common chemical element in the universe, just 10 years ago Herbst—a professor of physics, chemistry, and astronomy—and his colleagues discovered that there were also large quantities of alcohol in dust clouds in space. The presence of methyl formate suggests that other molecules may play a more prominent role in star and planet formation than scientists ever suspected. Herbst reported the new results June 23 at the International Symposium on Molecular Spectroscopy in Columbus.
"Even using our best models of interstellar chemistry, we still don't fully understand how these molecules could have formed," Herbst said. "Clearly, something else is going on."
Three groups of chemists from the United States, Canada, and Norway had previously conducted laboratory experiments to determine how alcohol and other molecules produce methyl formate. Herbst and Ohio State postdoctoral researcher Helen Roberts used that data to construct a new model of how such reactions happen in space, and then used the model to predict how much methyl formate would be found in the typical interstellar dust cloud.