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There are a total of 580 record(s) matching your query.
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Investigations into an unknown organism on the martian meteorite Allan Hills 84001
Author(s): Steele, A.; Goddard, D. T.; Stapleton, D.; Toporski, J. K.; Peters, V.; Bassinger, V.; Sharples, G.; Wynn-Williams, D. D.; McKay, D. S.
Abstract: Examination of fracture surfaces near the fusion crust of the martian meteorite Allan Hills (ALH) 84001 have been conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and has revealed ...
NASA Center: NASA (non Center Specific) Publication Year: 2000
Added to NTRS: 2006-08-02
Document ID: 20040088925
Astrobiology: exploring the origins, evolution, and distribution of life in the Universe
Author(s): Des Marais, D. J.; Walter, M. R.
Abstract: The search for the origins of life and its presence beyond Earth is strengthened by new technology and by evidence that life tolerates extreme conditions and that planets are widespread. Astrobiologists learn how planets ...
NASA Center: Ames Research Center Publication Year: 1999
Added to NTRS: 2006-08-02
Document ID: 20040088896
An intron within the 16S ribosomal RNA gene of the archaeon Pyrobaculum aerophilum
Author(s): Burggraf, S.; Larsen, N.; Woese, C. R.; Stetter, K. O.
Abstract: The 16S rRNA genes of Pyrobaculum aerophilum and Pyrobaculum islandicum were amplified by the polymerase chain reaction, and the resulting products were sequenced directly. The two organisms are closely related by this ...
NASA Center: NASA (non Center Specific) Publication Year: 1993
Added to NTRS: 2006-08-02
Document ID: 20050000499
Recognition of > or = 3850 Ma water-lain sediments in West Greenland and their significance for the early Archaean Earth
Author(s): Nutman, A. P.; Mojzsis, S. J.; Friend, C. R.
Abstract: A layered body of amphibolite, banded iron formation (BIF), and ultramafic rocks from the island of Akilia, southern West Greenland, is cut by a quartz-dioritic sheet from which SHRIMP zircon 206Pb/207Pb weighted mean ages ...
NASA Center: NASA (non Center Specific) Publication Year: 1997
Added to NTRS: 2006-08-02
Document ID: 20040089176
The sequence of Methanospirillum hungatei 23S rRNA confirms the specific relationship between the extreme halophiles and the Methanomicrobiales
Author(s): Burggraf, S.; Ching, A.; Stetter, K. O.; Woese, C. R.
Abstract: We have determined the sequence of the 23S rRNA from the methanogenic archaeon Methanospirillum hungatei. This is the first such sequence from a member of the Methanomicrobiales. Moreover, it brings additional evidence to ...
NASA Center: NASA (non Center Specific) Publication Year: 1991
Added to NTRS: 2006-08-02
Document ID: 20040089506
Sources and sinks for ammonia and nitrite on the early Earth and the reaction of nitrite with ammonia
Author(s): Summers, D. P.
Abstract: An analysis of sources and sinks for ammonia and nitrite on the early Earth was conducted. Rates of formation and destruction, and steady state concentrations of both species were determined by steady state kinetics. The ...
NASA Center: Ames Research Center Publication Year: 1999
Added to NTRS: 2006-08-02
Document ID: 20040142037
Climatic forcing of carbon-oxygen isotopic covariance in temperate-region marl lakes
Author(s): Drummond, C. N.; Patterson, W. P.; Walker, J. C.
Abstract: Carbon and oxygen stable isotopic compositions of lacustrine carbonate from a southeastern Michigan marl lake display linear covariance over a range of 4.0 Peedee belemnite (PDB) in oxygen and 3.9 (PDB) in carbon. ...
NASA Center: NASA (non Center Specific) Publication Year: 1995
Added to NTRS: 2006-08-02
Document ID: 20040089801
A possible prebiotic synthesis of pantetheine, a precursor to coenzyme A
Author(s): Keefe, A. D.; Newton, G. L.; Miller, S. L.
Abstract: The involvement of coenzyme A in many enzyme reactions suggests that it acted in this capacity very early in the development of life on Earth. Particularly relevant in this regard is its role in the activation of amino acids ...
NASA Center: NASA (non Center Specific) Publication Year: 1995
Added to NTRS: 2006-08-02
Document ID: 20050000233
Non-standard amino acid recognition by Escherichia coli leucyl-tRNA synthetase
Author(s): Martinis, S. A.; Fox, G. E.
Abstract: Recombinant E. coli leucyl-tRNA synthetase was screened for amino acid-dependent pyrophosphate exchange activity using noncognate aliphatic amino acids including norvaline, homocysteine, norleucine, methionine, and ...
NASA Center: Goddard Space Flight Center Publication Year: 1997
Added to NTRS: 2006-08-02
Document ID: 20040089262
Polymerization on the rocks: negatively-charged alpha-amino acids
Author(s): Hill, A. R. Jr; Bohler, C.; Orgel, L. E.
Abstract: Oligomers of the negatively-charged amino acids, glutamic acid, aspartic acid, and O-phospho-L-serine are adsorbed by hydroxylapatite and illite with affinities that increase with oligomer length. In the case of ...
NASA Center: NASA (non Center Specific) Publication Year: 1998
Added to NTRS: 2006-08-02
Document ID: 20040172675
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