Cyril Ponnamperuma

Aromatic Hydrocarbons in the Murchison Meteorite

Polynuclear aromatic hydrocarbons in the Murchison meteorite have been identified by the combined techniques of gas chromatography and mass spectrometry. The distribution of the aromatic compounds suggests that they are the products of a high-temperature synthesis.

Peptide Synthesis from Amino Acids in Aqueous Solution

Four dipeptides and a tripeptide were formed when an aqueous solution of glycine and leucine was exposed to ultraviolet light in the presence of cyanamide.

Amino acids indigenous to the murray meteorite.

Analysis of the Murray meteorite, a type II carbonaceous chondrite, has led to the identification of 17 amino acids. For seven of the amino acids nearly equal amounts of the D and L isomers are present, and 11 of the amino acids are not found in protein. These results suggest that these amino acids, like the amino acids of the Murchison meteorite, are extraterrestrial in origin.

Organic synthesis in a simulated Jovian atmosphere—II☆

Abstract Reactions which may occur in the Jovian atmosphere were simulated by passing an electrical discharge through a mixture of methane and ammonia. Analysis of the volatile fraction revealed the presence of several precursors of biologically important compounds. The nonvolatile fraction consisted of an orange-red polymer. This result may provide an explanation for the appearance of the red spot on the planet Jupiter.

Nucleotide Synthesis under Possible Primitive Earth Conditions

The nucleosides adenosine, guanosine, cytidine, uridine, and thymidine were each heated with inorganic phosphate. Nucleoside monophosphates were formed in appreciable yield. This result has a bearing on the hypothesis of chemical evolution.

Current status of chemical studies on the origin of life

Chemical studies of life origin, discussing chemical and biological evolution, precellular organization and synthesis of various life compounds

Primordial organic chemistry and the origin of life

Aspects of Darwinian revolution are discussed together with spontaneous generation, the inorganic chemical evolution, the primitive atmosphere, and interstellar matter. The significance of the change of the earths reducing atmosphere to an atmosphere with oxidizing characteristics is considered. Experiments regarding the abiogenic synthesis of nucleic acids and proteins are reported. It was found that micromolecules can be formed in simulation experiments. The condensation reaction taking place in the presence of water was studied together with the condensation reaction taking place in the relative absence of water or under hypohydrous conditions. Jupiter simulation studies were conducted, and lunar and meteorite material was analyzed.

Carbon, Carbides, and Methane in an Apollo 12 Sample

Total carbon in the Apollo 12 sample 12023 fines was 110 micrograms per gram of sample with a carbon isotopic abundance δ13C (relative to the Pee Dee belemnite standard) of +12 per mil. Hydrolysis of the fines with deuterium chloride yielded undeuterated methane along with deuterated hydrocarbons, thus confirming the presence of 7 to 21 micrograms of carbon per gram of sample as carbide and about 2 micrograms of carbon per gram of sample as indigenous methane. After vacuum pyrolysis of the fines to 1100�C the following gases were detected in the relative abundance: carbon monoxide 〉 carbon dioxide 〉 methane. Variations of the δ13C value with the pyrolysis temperature indicated the presence of carbon with more than one range of isotopic values. The observed δ13C value of +14 per mil for lunar carbide is much higher than that of carbide in meteorites. These results suggest that lunar carbide is either indigenous to the moon or a meteoritic contribution that has been highly fractionated isotopically.

ORGANIC COMPOUNDS IN THE MURCHISON METEORITE

Impressive supporting evidence for the concept of the chemical evolution of life has appeared in the discovery of biologically important compounds in extraterrestrial samples. The approaches pursued to detect extraterrestrial organic compounds include the study of interstellar space by radioastronomy, the evaluation of the Apollo lunar samples, and the analysis of meteorites, both ancient and recent. It has been found that the clouds of gas in the interstellar medium contain a wide variety of molecules, most of which are organic in nature. The carbonaceous chondrites contain polymeric organic matter. Amino acids have been detected in the Murchison meteorite.

Search for Organic Compounds in the Lunar Dust from the Sea of Tranquiblity

A sample of lunar dust was examined for organic compounds. Carbon detected in concentrations of 157 micrograms per gram had a δ13C per mil (PDB) value of + 20. Treatment with hydrochloric acid yielded hydrocarbons of low molecular weight, suggesting the presence of carbides. The gas chromatogram of the acylated and esterified derivatives of the hydrolyzate was similar to that obtained for the Pueblito de Allende meteorite. There were no detectable amounts of extractable high-molecular-weight alkanes, aromatic hydrocarbons, isoprenoid hydrocarbons, normal alkanes, fatty acids, amino acids, sugars, or nucleic acid bases. Traces of porphyrins were found, perhaps arising from rocket exhaust materials.