Search

Type III carbonaceous chondrite Murchison meteorite, obtaining amino acids, aliphatic and aromatic hydrocarbons from specimen

WE wish to report the formation of polyglycines by direct condensation of glycinamide as an example of the synthesis of linear polypeptides by polymerization of unsubstituted α-amino-acid amides.

Sarcina lutea was grown in Trypticase Soy Broth, Nutrient Broth, and a chemically defined medium. Gas chromatographic analysis of lipid components demonstrated that the composition of the medium had an effect on the relative per cent composition of the aliphatic hydrocarbons and fatty acids present in the cells. The branched olefinic hydrocarbons from the organisms grown in Trypticase Soy Broth showed no predominance or only a slight predominance of odd-numbered carbon chains, whereas the hydrocarbons from cells grown in the other two media showed an obvious predominance of odd-numbered carbon chains. The monocarboxylic fatty acid content and distribution showed only minor differences, with all normal saturated fatty acids present in relatively small quantities for cells grown in Nutrient Broth and in a chemically defined medium.

The experiments reported here have shown that by heating an aqueous mixture of formaldehyde and hydroxylamine hydrochloride, several amino acids, hydroxy acids, and other biochemical compounds are formed. The predominant amino acid formed is glycine. The conditions under which the reaction takes place have been studied in some detail. The mechanism of synthesis has also been studied. Formaldoxime, hydrogen cyanide, and ammonia are among the first products formed. Strecker and cyanohydrin condensations yield nitriles which are subsequently hydrolyzed to amides and finally to acids. Other condensation reactions are proposed to account for the formation of serine, alanine, β-alanine, and lactic acid. The interpretation of some previous photochemical syntheses of amino acids appears possible in the light of the present evidence. The experiments are of significance in relation to the formation of biochemical compounds, from simple compounds of carbon and nitrogen, under conditions assumed to have existed during the early development of the earth's crust.

A detailed study of a number of hydrocarbons observed in gas chromatographic analyses of six carbonaceous chondrites (Essebi, Grosnaja, Mokoia, Murray, Orgueil, and Vigarano) has resulted in the identification of nine homologous series of isomeric alkanes in addition to the normal alkane series. Two of them show isoprenoid structures corresponding to 2, 6, 10-trimethyl and 2, 6, 10, 14-tetramethyl alkanes. The individual members identified in each of these two series cover the ranges C14-C19 and C19-C21, respectively. The rest is made up of five series of monomethyl alkanes (6-, 5-, 4-, 3-, 2-methyl alkanes) and two of monocycloalkanes (cyclohexyl and cyclopentyl). The presence of members of the n-paraffin series between C11 and C21 inclusive was also confirmed by mass spectral data. The hydrocarbon content ranged from 6.7 to 82.8 ppm.

The condensation of mononucleotides has been carried out in aqueous solution at neutral pH in the presence of cyanamide. Oligodeoxyribonucleotides up to five units have been formed when montmorillonite was present.

The catalytic action of an alkaline earth metal oxide (MgO) on HCN in aqueous solution has been investigated. The reaction mixture was extracted with ether to give diaminomaleonitrile (DAMN). Acid hydrolysis of this mixture resulted in glycine, alanine, aspartic acid and unidentified ninhydrin-positive compounds. Acid hydrolysis of the material remaining after ether extraction (both water-soluble and water-insoluble components) resulted in adenine, aminoimidazole-carboxyamidine, and the amino acids glycine and alanine.

Normal paraffins in the C(16) to C(32) range and the saturated isoprenoid hydrocarbons, pristane and phytane, have been found in chert from the Gunflint iron formation (1.9 x 10(9) years old) of the north shore of Lake Superior. The distribution of n-alkanes shows two maxima, one at about C(18) to C(19) and the other at about C(22) with a minimum occurring at C(20) to C(21). No predominance of odd- to even-carbon-number alkanes is observed within the C(16) to C(32) range. The results agree with micropaleontological observations made on the Gunflint chert and provide a chemical characterization of Precambrian life existing about two eons ago.

An initial investigation into the mechanism of hydrocarbon biosynthesis in Sarcina lutea was performed by measuring the amounts of 14 C incorporated into the hydrocarbons and fatty acids by use of a combination gas chromatograph and high-temperature gas-flow ionization apparatus. Uniformly labeled l -isoleucine- 14 C was predominantly incorporated into the anteiso-branched chains. Palmitate- 16 - 14 C gave evidence that a direct correlation may exist between the nonpolar end of the palmitate and the biosynthesis of hydrocarbons and carotenoids. The label from palmitate- 1 - 14 C was incorporated into the various hydrocarbon groups as a compound, derived from the polar end of the palmitate, consisting of more than two carbon atoms. Palmitate- 16 - 14 C and - 1 - 14 C gave no detectable evidence that transformed products were incorporated into other fatty acids. Sodium acetate- 2 - 14 C and uniformly labeled l -leucine- 14 C gave evidence of a nonspecific incorporation into both the aliphatic hydrocarbons and fatty acids of Sarcina lutea .

Astrophysical observation and experimental results of organic synthesis bearing on abiogenic formation of biochemical compounds formed from simple precursor in aqueous or aqueous ammonia system

The racemization of some neutral α-amino acids in 6 N HCl was studied at 105°, 120°, and 130°. Alanine, α-aminobutyric acid, and leucine racemize at nearly the same rate, whereas the β-substituted valine and isoleucine are inverted more slowly. Under the conditions of acid hydrolysis (105°, 24 hours) the percentages of antipodes detected were: alanine, 1.1; valine, 0.3; isoleucine, 0.5; leucine, 1.3; and traces of proline. At 130° the equilibrium constant for the isomerization of isoleucine into allo -isoleucine was found to be K = 1.29.

Non-enzymic transamination reactions at 85 degrees between various amino acids and alpha-oxoglutaric acid are catalysed by metal ions, e.g. Al(3+), Fe(2+), Cu(2+) and Fe(3+). The reaction is optimum at pH4.0. Of the 14 amino acids studied histidine is the most active. In the presence of Al(3+) histidine transaminates with alpha-oxoglutaric acid, forming glutamic acid and Al(3+)-imidazolylpyruvic acid complex as the end products. However, in the presence of Fe(2+) or Cu(2+) the products are glutamic acid and a 1:2 metal ion-imidazolylpyruvic acid chelate. The greater effectiveness of histidine in these reactions is attributed to the presence of the tertiary imidazole nitrogen atom, which is involved in the formation of stable sparingly soluble metal ion-imidazolylpyruvic acid complexes or chelates as end products of these reactions. Of the metal ions studied only Al(3+), Fe(2+), Fe(3+) and Cu(2+) are effective catalysts for the transamination reactions, and EDTA addition completely inhibits the catalytic effect of the Al(3+). Spectrophotometric evidence is presented to demonstrate the presence of metal ion complexes of Schiff bases of histidine as intermediates in the transamination reactions. These results may contribute to understanding the role of histidine in enzyme catalysis.

The chlamydospores of Ustilago maydis , U. nuda , and Sphacelotheca reiliana were analyzed by gas chromatography and mass spectrometry for their hydrocarbon contents. For the first time we observed that they contain paraffinic hydrocarbons; the average contents were 42, 58, and 146 parts per million, respectively. n -Alkanes having odd numbers of carbon atoms predominate, with carbon-chain lengths ranging from C 14 to C 37 . The major alkanes are n -C 27 in U. maydis , n -C 27 and n -C 35 in U. nuda , and n -C 29 in S. reiliana . Each type of spore carried a distinctly characteristic population of hydrocarbons.

THE formation of adenine from hydrogen cyanide has been recently reported from this laboratory1. Continuing the work on the synthesis of biochemical compounds under possible primitive Earth conditions2, we now have investigated the direct formation of amino-acids from hydrogen cyanide.

Brief review of relevant information on the composition of stars, interstellar matter, and individual bodies of the solar system. An attempt is made to answer fundamental questions of organic cosmochemistry - namely, the nature of the organic and related molecules present in our Galaxy and solar system, the distribution of these molecules in different parts of the two systems, the mechanism of formation of these molecules, and the relation between these molecules and prebiological chemical evolution on the one hand, and terrestrial and, possibly, extraterrestrial biology, on the other. Detailed studies are made of the formation and chemical behavior of the organogenic elements in stars, interstellar matter, comets, meteorites, carbonaceous chondrites, and the terrestrial and Jovian planets.

Doped ceria deposits have been prepared on 3D-printed polyamide-12 components starting from inkjet-compatible solutions in an attempt to functionalize the surface of the plastic part, followed by a low temperature decomposition process at 160 °C in air. The non-continuous deposits were characterized by simultaneous thermogravimetric analysis, differential scanning calorimetry and evolved gas analysis, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, transmission electron microscopy and electron diffraction. After thermal treatment, the deposits are still clearly visible at the surface of the polymer. However, no crystallinity of the ceria is observed, in contrast to identical low temperature processing on inert substrates such as glass where nanoparticle ceria aggregates were produced. This is tentatively explained by the chemically-reducing character of the polyamide, and in particular to CO and hydrocarbon gases released during the heating process, which would continuously induce the reduction of Ce4+ to Ce3+ at the low temperature of 160 °C, influencing the non-detection of crystalline ceria.

A wide var iety of chemical processes have been used for the synthesis of amino acids from prebiot ic molecular precursors under plausible pr imi t ive Earth conditions (M i l l e r , 1982). The prebiot ic formation of a l l protein-type amino acids has been demonstrated except for three amino acids: h is t id ine , lys ine, and arginine (Weber and Mi l l e r , 1981). As a continuation of our work on the prebiot ic synthesis of imidazole, 2-methylimidazole, and 4-methylimidazole (Or6 et a l . , 1984), th is paper reports the prebiot ic synthesis of other imidazoles (l~-4-acetaldehyde, Im-4-glycol, and Im-4-ethanol), which are among the intermediate products in the proposed prebiot ic synthet ic pathway of h is t id ine.

The cometary modelling of Greenberg (1982), Delsemme (1984) and others suggests a close relationship between interstellar gases and grains, and comets. Cometary nuclei, assembled from primordial dust and ices, are the most "pristine" and thus the most interesting art i facts of the presolar nebula. Excluding H, He, and Ne as too volatile to condense, the elemental abundances of comets are found to approximate solar abundances. But, a four-fold depletion of carbon has yet to be satisfactorily explained. Delsemme has considered loss of volatile methane, formation of graphite grains and cold temperature shift of the CO+3H2=CHh+H20 equilibrium toward CO (Delsemme, 1977). Another possib i l i ty is a large mass fraction (0.19 of heavy organic compounds (Greenberg, 1982).

By means of flow microfluorometry, the protein and nucleic acid contents of individual bacterial cells may be measured at the rate of several thousand cells per second. Accumulation of such information over a few minutes yields the composition distribution of the microbial population. These distributions have been determined at different times during batch growth of Bactillus subtilis, and the results indicate that the variance of cell composition decreases as the population passes through the exponential into the stationary phase. The relative abundance of endospores and vegetative cells as well as the protein distributions of these subpopulations may be readily determined from flow microfluorometry data. Experimental access to such details of microbial population dynamics should foster improved understanding of cell growth, spore germination, and spore formation kinetics.

The hypothesis that RNA preceded double-stranded DNAmolecules as the reservoir of cellular genetic information (Lazcano, et al., 1988a), implies that the replicase activity observed in vitro under slightly modified laboratory conditions for normally DNA-dependent eubacterial and eukaryotic RNA polymerases is a v.estigial property preserved from early Archean times (Lazcano et al. , 1988b). The oldest component of contemporary cellular RNA polymerases was a small, multifunctional, Zn ++ dependent basic polypeptide. Based on a co~arison of their primary structures and on their position on bacterial genomes, we suggest that the B and 8' subunits of the E. coli RNA polymerases and their homologues, are the result of an earyl~andem duplication of the gene coding in the ancestral RNA cellular genome for the single-unit RNA replicase.

A possible prebiotic synthesis of thymine has been achieved via the methylation of uracil with formaldehyde and hydrazine.

Apollo 11 and 12 lunar soil samples common contaminant identified as diisopropyl disulfide, using chromatograph mass spectrometer

Carbonaceous chondrite and Precambrian chert amino acids detection, using simultaneous optical configuration determination and gas chromatography