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Astrobiologists Reproduce RNA Component in Laboratory
NASA astrobiologists studying the origin of life have reproduced uracil, a key component of RNA, in the laboratory. They discovered that an ice sample containing pyrimidines exposed to ultraviolet radiation under space-like conditions produces this essential ingredient of life. The study appears in the September issue of Astrobiology.
“We have demonstrated for the first time that we can make uracil, a component of RNA, non-biologically in a laboratory under conditions found in space,” said Michel Nuevo, research scientist at NASA’s Ames Research Center. “We are showing that these laboratory processes, which simulate occurrences in...
Source: [NASA Press Release]
November 6, 2009 / Posted by: Daniella Scalice
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Oxygen Production in Earth's Early Oceans Predates the Great Oxidation Event
It is widely accepted that around 2.4 billion years ago, the Earth’s atmosphere underwent a dramatic change when oxygen levels rose sharply. Called the “Great Oxidation Event” (GOE), the oxygen spike marks an important milestone in Earth’s history, the transformation from an oxygen-poor atmosphere to an oxygen-rich one paving the way for complex life to develop on the planet.
Two questions that remain unresolved in studies of the early Earth are when oxygen production via photosynthesis got started and when it began to alter the chemistry of Earth’s ocean and atmosphere.
A research team that includes members of NAI’s Arizona...
Source: [Link]
November 4, 2009 / Posted by: Daniella Scalice
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'Ultra-Primitive' Particles Found in Comet Dust
Scanning electron images of two dust particles E1 (panel A) and G4 (B) and secondary ion mass spectrometry isotopic ratio maps (C–D). Oxygen isotope maps of particles E1 (C) and G4 (D) show four and seven isotopically anomalous regions, indicated by circles, which have been identified as presolar grains. The scale bars are 2 microns.Dust samples collected by high-flying aircraft in the upper atmosphere have yielded an unexpectedly rich trove of relicts from the ancient cosmos, report scientists from NAI’s Carnegie Institution of Washington team in Earth and Planetary Science Letters. The stratospheric dust includes minute grains that likely formed inside stars that lived and died long before the birth of our sun, as well as material from molecular clouds in interstellar space. This “ultra-primitive” material likely wafted into the atmosphere after the Earth passed through the trail of an Earth-crossing comet in 2003, giving scientists a rare opportunity to...
Source: [Link]
November 2, 2009 / Posted by: Daniella Scalice
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Diving Through A Microbial Landscape
Scientist Dale Andersen prepares to dive in Lake Untersee in Queen Maud Land in Antarctica. Photo: Dale Andersen
The ice-covered lakes of Antarctica’s McMurdo Dry Valleys have long been of interest to astrobiologists. These remote and extreme environments harbor unique microbial ecosystems that could provide clues about how life might survive on other worlds – such as Jupiter’s icy moon, Europa. Recently, a team of scientists funded by the NASA Exobiology Program began exploring the unique habitat of the ice-crusted Lake Joyce.
Lake Joyce is of special interest, because it’s waters harbor carbonate structures known as microbialites. These unique structures are formed with layers of cyanobacteria. The research team is interested in how these organisms...Source: [OnOrbit]
October 29, 2009 / Posted by: Aaron Gronstal
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Ribosomes as Ancient Molecular Fossils
Members of NAI’s team at Georgia Tech have a new paper in Molecular Biology and Evolution describing an analysis of ribosomal structure and sequence. Their approach chronicles the ribosome’s evolution, effectively interpreting the ribosome as a fossil. Using the highest resolution structures available, of two species that represent disparate regions of the evolutionary tree, they have sectioned the large subunit of each ribosome into concentric shells, like an onion, using the site of peptidyl transfer as the origin. Their results suggest that the structure and interactions of both RNA and protein can...
October 28, 2009 / Posted by: Daniella Scalice
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Ice in the Solar System...in Your Classroom
Exploring Ice in the Solar System is a series of lessons for K-5 classrooms developed by the NAI Carnegie Institution of Washington Team and the NASA MESSENGER mission. Twelve lessons span topics from ice in everyday life, to exploring ice in the polar regions of Earth, to icy places on Mars and Europa, to life in ice. Each standards-aligned lesson consists of substantive background information, inquiry-based activities, teaching tips, resources, a photo gallery, and strategies for differentiated instruction and evaluation.
October 27, 2009 / Posted by: Daniella Scalice
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Spotting Spores
Adrian Ponce, deputy manager for JPL’s planetary science section, has devised a new microscope-based method to quickly validate — from days to minutes — a spacecraft’s cleanliness. The method will help in decontaminating spacecraft before launch, and could have medical and pharmaceutical uses on Earth.
Source: [JPL]
October 27, 2009 / Posted by: Aaron Gronstal
Astrobiology Field Work
Rollover map to explore Astrobiology field sites around the world.
