Miller/urey experiment

@article{doi101126science1173046528,
    author = "Miller, S.",
    title = "A production of amino acids under possible primitive earth conditions.",
    year = "1953",
    journal = "Science",
    url = "https://www.semanticscholar.org/paper/c82119aed73838366ea5e8728be939df4fba6109",
    doi = "10.1126/SCIENCE.117.3046.528",
    is_oa = "true",
    number = "3046",
    pages = "528-529",
    semanticscholar_citation_count = "2957",
    semanticscholar_id = "c82119aed73838366ea5e8728be939df4fba6109",
    volume = "117"
}

@article{miller1953a,
    author = "Miller, Stanley L.",
    title = "A Production of Amino Acids Under Possible Primitive Earth Conditions",
    year = "1953",
    journal = "Science",
    url = "https://doi.org/10.1126/science.117.3046.528",
    doi = "10.1126/science.117.3046.528",
    number = "3046",
    openalex = "W2054249920",
    pages = "528-529",
    volume = "117",
    references = "doi101073pnas384351, doi10108803701298629301, doi101126science1173046529"
}

@misc{miller1953a1,
    author = "Miller, S",
    title = "A Production of Amino Acids Under Possible Primitive Earth Conditions",
    year = "1953",
    howpublished = "Science, v. 117, p. 528-529",
    note = "talkorigins\_source = {true}; raw\_reference = {Miller, S., 1953, A Production of Amino Acids Under Possible Primitive Earth Conditions: Science, v. 117, p. 528-529.}"
}

@article{crossref1954the,
    title = "THE PRODUCTION OF AMINO ACIDS UNDER POSSIBLY PRIMITIVE EARTH CONDITIONS",
    year = "1954",
    journal = "Medical Journal of Australia",
    url = "https://doi.org/10.5694/j.1326-5377.1954.tb85409.x",
    doi = "10.5694/j.1326-5377.1954.tb85409.x",
    number = "10",
    openalex = "W4254388662",
    pages = "372-372",
    volume = "1"
}

@article{doi101021ja01614a001,
    author = "Miller, S.",
    title = "Production of Some Organic Compounds under Possible Primitive Earth Conditions1",
    year = "1955",
    journal = "Journal of the American Chemical Society",
    url = "https://www.semanticscholar.org/paper/b45bcb6258c4a6a63f0616c134102e77841a55f5",
    doi = "10.1021/JA01614A001",
    is_oa = "true",
    number = "9",
    pages = "2351-2361",
    semanticscholar_citation_count = "742",
    semanticscholar_id = "b45bcb6258c4a6a63f0616c134102e77841a55f5",
    volume = "77"
}

@article{doi1010160003986161900339,
    author = "Oró, J. and Kimball, A. P.",
    title = "Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide",
    year = "1961",
    journal = "Archives of Biochemistry and Biophysics",
    url = "https://doi.org/10.1016/0003-9861(61)90033-9",
    doi = "10.1016/0003-9861(61)90033-9",
    openalex = "W1974519483",
    references = "doi1010160006291x60901388, doi1010160006300257903669, doi101016s0021925817309419, doi101021ja01614a001, doi101038190389a0, doi101038190442a0, doi101086145272, doi101126science1303370245, doi105962bhltitle4528, openalexw2983850269, oró1961aminoacid"
}

@article{oró1961aminoacid,
    author = "ORÓ, J. and KAMAT, S. S.",
    title = "Amino-acid Synthesis from Hydrogen Cyanide under Possible Primitive Earth Conditions",
    year = "1961",
    journal = "Nature",
    url = "https://doi.org/10.1038/190442a0",
    doi = "10.1038/190442a0",
    number = "4774",
    openalex = "W2018424476",
    pages = "442-443",
    volume = "190",
    references = "doi101002ange19600721104, doi101002cber187400701244, doi1010160003986159904552, doi1010160006291x60901388, doi101016s0021925818714282, doi101021ac60140a035"
}

@article{doi1010160003986162904125,
    author = "Oró, J. and Kimball, A. P.",
    title = "Synthesis of purines under possible primitive earth conditions",
    year = "1962",
    journal = "Archives of Biochemistry and Biophysics",
    url = "https://doi.org/10.1016/0003-9861(62)90412-5",
    doi = "10.1016/0003-9861(62)90412-5",
    openalex = "W1530759103",
    references = "oró1961aminoacid"
}

@article{doi101038199222a0,
    author = "Ponnamperuma, Cyril and Sagan, Carl and Mariner, Ruth",
    title = "Synthesis of Adenosine Triphosphate Under Possible Primitive Earth Conditions",
    year = "1963",
    journal = "Nature",
    url = "https://doi.org/10.1038/199222a0",
    doi = "10.1038/199222a0",
    openalex = "W1998305216"
}

In this paper the nature of the primitive atmosphere and ocean is considered in the light of geologic and geophysical information. The hypothesis of an early methane-ammonia atmosphere is found to be without solid foundation and indeed is contraindicated. Geologists favor an alternative view-that genesis of air and oceans is a result of planetary outgassing. Some consequences of this view are examined. Volatiles from outgassing interacted with the alkaline crust to form an ocean having a pH 8-9 and tzo produce an atmosphere consisting of CO, C02, N2, and H2. Radiation interacting with such a mixture yields HCN as a principal product. Ultraviolet irradiation of HCN solutions at pH 8-9 yields amino acids and other important substances of biologic interest. The nature of the earth's environment limited the kinds of compounds that might have accumulated in a soup. Arguments concerning feasible components support the view that amino acids and proteins preceded sugars and nucleic acids. If the methane-ammonia hypothesis were correct, there should be geochemical evidence supporting it. What is the evidence for a primitive methane-ammonia atmosphere on earth? The answer is that there is no evidence for it, but much against it. The methane-ammonia hypothesis is in major trouble with respect to the ammonia component, for ammonia on the primitive earth would have quickly disappeared. The effective threshold for degradation by ultraviolet radiation is 2,250 A. A quantity of ammonia equivalent to present atmospheric nitrogen would be destroyed in -30,000 years. Small amounts of ammonia would be reformed, but this process is unimportant in comparison to the destruction. If large amounts of methane had ever been present in the earth's atmosphere, geologic evidence for it should also be available. Laboratory experiments show that one consequence of irradiating a dense, highly reducing atmosphere is the production of hydrophobic organic molecules which are adsorbed by sedimenting clays. The earliest rocks should contain an unusually large proportion of carbon or organic chemicals. This is not the case. The composition of the present atmosphere with respect to the gases neon, argon, krypton, and xenon is crucial. Neon is present on earth to an extent about 10-1O

@article{doi101073pnas5561365,
    author = "Abelson, Philip H.",
    title = "CHEMICAL EVENTS ON THE PRIMITIVE EARTH",
    year = "1966",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "In this paper the nature of the primitive atmosphere and ocean is considered in the light of geologic and geophysical information. The hypothesis of an early methane-ammonia atmosphere is found to be without solid foundation and indeed is contraindicated. Geologists favor an alternative view-that genesis of air and oceans is a result of planetary outgassing. Some consequences of this view are examined. Volatiles from outgassing interacted with the alkaline crust to form an ocean having a pH 8-9 and tzo produce an atmosphere consisting of CO, C02, N2, and H2. Radiation interacting with such a mixture yields HCN as a principal product. Ultraviolet irradiation of HCN solutions at pH 8-9 yields amino acids and other important substances of biologic interest. The nature of the earth's environment limited the kinds of compounds that might have accumulated in a soup. Arguments concerning feasible components support the view that amino acids and proteins preceded sugars and nucleic acids. If the methane-ammonia hypothesis were correct, there should be geochemical evidence supporting it. What is the evidence for a primitive methane-ammonia atmosphere on earth? The answer is that there is no evidence for it, but much against it. The methane-ammonia hypothesis is in major trouble with respect to the ammonia component, for ammonia on the primitive earth would have quickly disappeared. The effective threshold for degradation by ultraviolet radiation is 2,250 A. A quantity of ammonia equivalent to present atmospheric nitrogen would be destroyed in -30,000 years. Small amounts of ammonia would be reformed, but this process is unimportant in comparison to the destruction. If large amounts of methane had ever been present in the earth's atmosphere, geologic evidence for it should also be available. Laboratory experiments show that one consequence of irradiating a dense, highly reducing atmosphere is the production of hydrophobic organic molecules which are adsorbed by sedimenting clays. The earliest rocks should contain an unusually large proportion of carbon or organic chemicals. This is not the case. The composition of the present atmosphere with respect to the gases neon, argon, krypton, and xenon is crucial. Neon is present on earth to an extent about 10-1O",
    url = "https://doi.org/10.1073/pnas.55.6.1365",
    doi = "10.1073/pnas.55.6.1365",
    openalex = "W2087373898"
}

The formation of amino acids by the action of electric discharges on a mixture of methane, nitrogen, and water with traces of ammonia was studied in detail. The presence of glycine, alanine, alpha-amino-n-butyric acid, alpha-aminoisobutyric acid, valine, norvaline, isovaline, leucine, isoleucine, alloisoleucine, norleucine, proline, aspartic acid, glutamic acid, serine, threonine, allothreonine, alpha-hydroxy-gamma-aminobutyric acid, and alpha,gamma-diaminobutyric acid was confirmed by ion-exchange chromatography and gas chromatography-mass spectrometry. All of the primary alpha-amino acids found in the Murchison Meteorite have been synthesized by this electric discharge experiment.

@article{doi101073pnas693765,
    author = "Ring, David and Wolman, Y. and Friedmann, Nadav and Miller, Stanley L.",
    title = "Prebiotic Synthesis of Hydrophobic and Protein Amino Acids",
    year = "1972",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The formation of amino acids by the action of electric discharges on a mixture of methane, nitrogen, and water with traces of ammonia was studied in detail. The presence of glycine, alanine, alpha-amino-n-butyric acid, alpha-aminoisobutyric acid, valine, norvaline, isovaline, leucine, isoleucine, alloisoleucine, norleucine, proline, aspartic acid, glutamic acid, serine, threonine, allothreonine, alpha-hydroxy-gamma-aminobutyric acid, and alpha,gamma-diaminobutyric acid was confirmed by ion-exchange chromatography and gas chromatography-mass spectrometry. All of the primary alpha-amino acids found in the Murchison Meteorite have been synthesized by this electric discharge experiment.",
    url = "https://doi.org/10.1073/pnas.69.3.765",
    doi = "10.1073/pnas.69.3.765",
    openalex = "W2070820093"
}

@article{flores1972polymerization,
    author = "Flores, Jose J. and Ponnamperuma, Cyril",
    title = "Polymerization of amino acids under primitive earth conditions",
    year = "1972",
    journal = "Journal of Molecular Evolution",
    url = "https://doi.org/10.1007/bf01653937",
    doi = "10.1007/bf01653937",
    number = "1",
    openalex = "W1965049674",
    pages = "1-9",
    volume = "2",
    references = "doi101016s0022283667800378, doi101021ja01499a069, doi101021ja01614a001, doi101038199219a0, doi101038201335a0, doi101038205284b0, doi1010382151230a0, doi101073pnas5641087, lemmon1970chemical, openalexw3038835020"
}

@article{doi101007bf01733839,
    author = "Ferris, James P. and Joshi, P. C. and Edelson, E. H. and Lawless, John",
    title = "HCN: A plausible source of purines, pyrimidines and amino acids on the primitive earth",
    year = "1978",
    journal = "Journal of Molecular Evolution",
    url = "https://doi.org/10.1007/bf01733839",
    doi = "10.1007/bf01733839",
    openalex = "W1978524762",
    references = "oró1961aminoacid"
}

@incollection{crossref197933,
    title = "33. A Production of Amino Acids under Possible Primitive Earth Conditions",
    year = "1979",
    booktitle = "A Source Book in Astronomy and Astrophysics, 1900–1975",
    url = "https://doi.org/10.4159/harvard.9780674366688.c36",
    doi = "10.4159/harvard.9780674366688.c36",
    openalex = "W4241288232",
    pages = "203-206"
}

Ab initio theoretical calculation was carried out to study the hydrolysis of amino malononitrile. The proposed scheme was considered as one of the possible reaction paths that the simplest amino acid, glycine, may be synthesized by the nature. Several other probable schemes based on the potential reaction sites of amino malononitrile were also examined. The optimized structures of the species on the reaction potential energy surfaces in addition to the activation energies were calculated at both HF and MP2 levels. The basis set superposition error (BSSE) for the correction of calculated energy was also performed. It came out that one of the proposed reactions had the lower potential energy profile in the sequential processes to form the amino acetonitrile. Most of the calculated barriers in this scheme were below 60 kcal/mol. The first added H2O in the hydrolysis of amino malononitrile was calculated to be at lower barrier (49.00 kcal/mol) on attacking one of the nitrile group of amino malononitrile and successively forming an amide, rather than attacking on the amino group of amino malononitrile (82.24 kcal/mol). Further frontier orbital analysis also proved the same fact. The second H2O molecule was added to hydrolyze the forming amide and produced carboxylic acid, which then underwent decarboxylation to form amino acetonitrile. Direct decarboxylation needs around 61 kcal/mol to cross the barrier, the highest one in all the processes derived in Scheme 1. Of course, it may be assisted by the third molecule such as H2O to lower the barrier (around 20 kcal/mol). From the calculated low barriers the proposed processes in Scheme 1 may be considered as one of the acceptable mechanisms in prebiotic chemical evolution on the primitive earth.

@article{doi101021jp010455q,
    author = "Zhu, Hong-Shun and Ho, Jia‐Jen",
    title = "Ab Initio Study of Hydrolysis of Amino Malononitrile: Formation of Amino Acetonitrile",
    year = "2001",
    journal = "The Journal of Physical Chemistry A",
    abstract = "Ab initio theoretical calculation was carried out to study the hydrolysis of amino malononitrile. The proposed scheme was considered as one of the possible reaction paths that the simplest amino acid, glycine, may be synthesized by the nature. Several other probable schemes based on the potential reaction sites of amino malononitrile were also examined. The optimized structures of the species on the reaction potential energy surfaces in addition to the activation energies were calculated at both HF and MP2 levels. The basis set superposition error (BSSE) for the correction of calculated energy was also performed. It came out that one of the proposed reactions had the lower potential energy profile in the sequential processes to form the amino acetonitrile. Most of the calculated barriers in this scheme were below 60 kcal/mol. The first added H2O in the hydrolysis of amino malononitrile was calculated to be at lower barrier (49.00 kcal/mol) on attacking one of the nitrile group of amino malononitrile and successively forming an amide, rather than attacking on the amino group of amino malononitrile (82.24 kcal/mol). Further frontier orbital analysis also proved the same fact. The second H2O molecule was added to hydrolyze the forming amide and produced carboxylic acid, which then underwent decarboxylation to form amino acetonitrile. Direct decarboxylation needs around 61 kcal/mol to cross the barrier, the highest one in all the processes derived in Scheme 1. Of course, it may be assisted by the third molecule such as H2O to lower the barrier (around 20 kcal/mol). From the calculated low barriers the proposed processes in Scheme 1 may be considered as one of the acceptable mechanisms in prebiotic chemical evolution on the primitive earth.",
    url = "https://doi.org/10.1021/jp010455q",
    doi = "10.1021/jp010455q",
    openalex = "W2040974338",
    references = "doi101126science1173046529"
}

@article{doi101038416475b,
    author = "Fuller, S.",
    title = "Communication should not be left to scientists",
    year = "2002",
    journal = "Nature",
    url = "https://www.nature.com/articles/416475b.pdf",
    doi = "10.1038/416475B",
    is_oa = "true",
    number = "6880",
    pages = "475-475",
    semanticscholar_citation_count = "2",
    semanticscholar_id = "86b03fffff366698468ea66b3efd2adc287abb1b",
    volume = "416"
}

@article{doi101007bf00927019,
    author = "Miller, S.",
    title = "The atmosphere of the primitive Earth and the prebiotic synthesis of amino acids",
    year = "2004",
    journal = "Origins of life",
    url = "https://www.semanticscholar.org/paper/08137718242a2e1142ec88d0c93e0e5132260aaa",
    doi = "10.1007/BF00927019",
    is_oa = "true",
    number = "1-2",
    pages = "139-151",
    semanticscholar_citation_count = "27",
    semanticscholar_id = "08137718242a2e1142ec88d0c93e0e5132260aaa",
    volume = "5"
}

@article{doi101023borig00000431229785679,
    author = "Cheng, C. M. and Liu, X. H. and Li, Y. and Ma, Y. and Tan, B. and Wan, R. and Zhao, Y. F.",
    title = "N-Phosphoryl Amino Acids and Biomolecular Origins. Review Paper in Honor of the 50th Anniversary of the Publication of ``A Production of Amino Acids under Possible Primitive Earth Conditions'' (Miller, 1953)",
    year = "2004",
    journal = "Origins of life and evolution of the biosphere",
    url = "https://www.semanticscholar.org/paper/29470adeb91f41cf9212dd5587107b69f0cb9c68",
    doi = "10.1023/B:ORIG.0000043122.97856.79",
    is_oa = "true",
    number = "5",
    pages = "455-464",
    semanticscholar_citation_count = "26",
    semanticscholar_id = "29470adeb91f41cf9212dd5587107b69f0cb9c68",
    volume = "34"
}

Amino acids were most likely available on the primitive Earth, produced in the primitive atmosphere or in hydrothermal vents. Import of extraterrestrial amino acids may have represented the major supply, as suggested by micrometeorite collections and simulation experiments in space and in the laboratory. Selective condensation of amino acids in water has been achieved via N-carboxy anydrides. Homochiral peptides with an alternating sequence of hydrophobic and hydrophilic amino acids adopt stereoselective and thermostable beta-pleated sheet structures. Some of the homochiral beta-sheets strongly accelerate the hydrolysis of oligoribonucleotides. The beta-sheet-forming peptides have also been shown to protect their amino acids from racemization. Even if peptides are not able to self-replicate, i.e., to replicate a complete sequence from the mixture of amino acids, the accumulation of chemically active peptides on the primitive Earth appears plausible via thermostable and stereoselective beta-sheets made of alternating sequences.

@article{doi101002cbdv200790057,
    author = "Brack, André",
    title = "From Interstellar Amino Acids to Prebiotic Catalytic Peptides: A Review",
    year = "2007",
    journal = "Chemistry \& Biodiversity",
    abstract = "Amino acids were most likely available on the primitive Earth, produced in the primitive atmosphere or in hydrothermal vents. Import of extraterrestrial amino acids may have represented the major supply, as suggested by micrometeorite collections and simulation experiments in space and in the laboratory. Selective condensation of amino acids in water has been achieved via N-carboxy anydrides. Homochiral peptides with an alternating sequence of hydrophobic and hydrophilic amino acids adopt stereoselective and thermostable beta-pleated sheet structures. Some of the homochiral beta-sheets strongly accelerate the hydrolysis of oligoribonucleotides. The beta-sheet-forming peptides have also been shown to protect their amino acids from racemization. Even if peptides are not able to self-replicate, i.e., to replicate a complete sequence from the mixture of amino acids, the accumulation of chemically active peptides on the primitive Earth appears plausible via thermostable and stereoselective beta-sheets made of alternating sequences.",
    url = "https://doi.org/10.1002/cbdv.200790057",
    doi = "10.1002/cbdv.200790057",
    openalex = "W2015254588",
    references = "doi10108803701298629301"
}

Miller's 1950s experiments used, besides the apparatus known in textbooks, one that generated a hot water mist in the spark flask, simulating a water vapor-rich volcanic eruption. We found the original extracts of this experiment in Miller's material and reanalyzed them. The volcanic apparatus produced a wider variety of amino acids than the classic one. Release of reduced gases in volcanic eruptions accompanied by lightning could have been common on the early Earth. Prebiotic compounds synthesized in these environments could have locally accumulated, where they could have undergone further processing.

@article{doi101126science1161527,
    author = "Johnson, Adam P. and Cleaves, Henderson James and Dworkin, Jason P. and Glavin, D. P. and Lazcano, Antonio and Bada, Jeffrey L.",
    title = "The Miller Volcanic Spark Discharge Experiment",
    year = "2008",
    journal = "Science",
    abstract = "Miller's 1950s experiments used, besides the apparatus known in textbooks, one that generated a hot water mist in the spark flask, simulating a water vapor-rich volcanic eruption. We found the original extracts of this experiment in Miller's material and reanalyzed them. The volcanic apparatus produced a wider variety of amino acids than the classic one. Release of reduced gases in volcanic eruptions accompanied by lightning could have been common on the early Earth. Prebiotic compounds synthesized in these environments could have locally accumulated, where they could have undergone further processing.",
    url = "https://doi.org/10.1126/science.1161527",
    doi = "10.1126/science.1161527",
    openalex = "W2164222049",
    references = "doi101007bf01809389, doi101007bf01810857, doi101016s0377027300001815, doi101021ja01614a001, doi101023a1024807125069, doi101073pnas693765, doi101126science1102722, miller1953a"
}

Of the 20 amino acids used in proteins, 10 were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these 10 early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.

@article{doi101089ast20080280,
    author = "Higgs, Paul G. and Pudritz, Ralph E.",
    title = "A Thermodynamic Basis for Prebiotic Amino Acid Synthesis and the Nature of the First Genetic Code",
    year = "2009",
    journal = "Astrobiology",
    abstract = "Of the 20 amino acids used in proteins, 10 were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these 10 early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.",
    url = "https://doi.org/10.1089/ast.2008.0280",
    doi = "10.1089/ast.2008.0280",
    openalex = "W2071801216",
    references = "doi101007bf01734482, doi1010160016703794902887, doi101038199219a0"
}

Mars is a CO(2)-abundant planet, whereas early Earth is thought to be also CO(2)-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO(2)/liquid H(2)O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life's origin.

@article{doi103390ijms10062722,
    author = "Fujioka, Kouki and Futamura, Yasuhiro and Shiohara, Tomoo and Hoshino, Akiyoshi and Kanaya, Fumihide and Manome, Yoshinobu and Yamamoto, Kenji",
    title = "Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System",
    year = "2009",
    journal = "International Journal of Molecular Sciences",
    abstract = "Mars is a CO(2)-abundant planet, whereas early Earth is thought to be also CO(2)-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO(2)/liquid H(2)O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life's origin.",
    url = "https://doi.org/10.3390/ijms10062722",
    doi = "10.3390/ijms10062722",
    openalex = "W2165301493"
}

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H(2)S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H(2)S, CH(4), NH(3), and CO(2). A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H(2)S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H(2)S may have played an important role in prebiotic reactions in early solar system environments.

@article{doi101073pnas1019191108,
    author = "Parker, Eric T. and Cleaves, Henderson James and Dworkin, Jason P. and Glavin, D. P. and Callahan, Michael P. and Aubrey, A. D. and Lazcano, Antonio and Bada, Jeffrey L.",
    title = "Primordial synthesis of amines and amino acids in a 1958 Miller H 2 S-rich spark discharge experiment",
    year = "2011",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H(2)S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H(2)S, CH(4), NH(3), and CO(2). A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H(2)S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H(2)S may have played an important role in prebiotic reactions in early solar system environments.",
    url = "https://doi.org/10.1073/pnas.1019191108",
    doi = "10.1073/pnas.1019191108",
    openalex = "W2135893268",
    references = "doi101126science1161527"
}

Question how life originated on the primitive earth is still a frontier of science. Nowadays, primitive life-like system is mostly considered to have emerged by chemical evolution on the Earth although some scientists are evaluating the possibility of panspermia hypothesis [1-3]. External and internal energies from the earth, such as cosmic rays, ultra violet radiation, meteorite impacts, volcanic eruption, submarine hydrothermal vent system, etc. resulted in organic molecules from inorganic materials, such as primitive atmospheric gas, minerals, materials solved in the ocean. Organic molecules were polymerized and finally resulted in several biological functions. Complex mixtures of the organic molecules should have evolved to primitive life-like systems. By the Miller-Urey experiment at 1953, a scenario from simple molecules to organic molecules in a simulated primitive atmosphere – ocean system was evaluated for the first time [4]. After the Miller-Urey experiment, the origin of life problem became as a scientific subject and a number of simulation experiments were carried out to elucidate how life-like system was originated on this planet [5-7].

@article{doi10577258222,
    author = "Kawamura, K.",
    title = "Oligomerization of Nucleic Acids and Peptides under the Primitive Earth Conditions",
    year = "2014",
    booktitle = "Oligomerization of Chemical and Biological Compounds",
    abstract = "Question how life originated on the primitive earth is still a frontier of science. Nowadays, primitive life-like system is mostly considered to have emerged by chemical evolution on the Earth although some scientists are evaluating the possibility of panspermia hypothesis [1-3]. External and internal energies from the earth, such as cosmic rays, ultra violet radiation, meteorite impacts, volcanic eruption, submarine hydrothermal vent system, etc. resulted in organic molecules from inorganic materials, such as primitive atmospheric gas, minerals, materials solved in the ocean. Organic molecules were polymerized and finally resulted in several biological functions. Complex mixtures of the organic molecules should have evolved to primitive life-like systems. By the Miller-Urey experiment at 1953, a scenario from simple molecules to organic molecules in a simulated primitive atmosphere – ocean system was evaluated for the first time [4]. After the Miller-Urey experiment, the origin of life problem became as a scientific subject and a number of simulation experiments were carried out to elucidate how life-like system was originated on this planet [5-7].",
    url = "https://openresearchlibrary.org/ext/api/media/67e4d5be-2e3e-4e20-93a5-840acb7f8c28/assets/external\_content.pdf",
    doi = "10.5772/58222",
    is_oa = "true",
    semanticscholar_citation_count = "3",
    semanticscholar_id = "11b31522bb3dd5c019fc91d3ab44ab90236de78c"
}

+ CO. We show that RNA nucleobases are synthesized in these experiments, strongly supporting the possibility of the emergence of biologically relevant molecules in a reducing atmosphere. The reconstructed synthetic pathways indicate that small radicals and formamide play a crucial role, in agreement with a number of recent experimental and theoretical results.

@article{doi101073pnas1700010114,
    author = "Ferus, Martin and Pietrucci, Fabio and Saitta, A. Marco and Knížek, Antonín and Kubelík, Petr and Ivanek, Ondřej and Shestivská, Violetta and Civiš, Svatopluk",
    title = "Formation of nucleobases in a Miller–Urey reducing atmosphere",
    year = "2017",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "+ CO. We show that RNA nucleobases are synthesized in these experiments, strongly supporting the possibility of the emergence of biologically relevant molecules in a reducing atmosphere. The reconstructed synthetic pathways indicate that small radicals and formamide play a crucial role, in agreement with a number of recent experimental and theoretical results.",
    url = "https://doi.org/10.1073/pnas.1700010114",
    doi = "10.1073/pnas.1700010114",
    openalex = "W2605468113",
    references = "doi101073pnas1422225112"
}

@article{s254f04a883c67c44d19ce996f13c750b98b282615,
    author = "Kobayashi, Kensei and Aoki, R. and Kebukawa, Y. and Shibata, H. and Fukuda, H. and Kondo, K. and Oguri, Y. and Airapetian, V.",
    title = "Prebiotic Formation of Amino Acid Precursors in Primitive Earth Atmosphere by Cosmic Rays and Solar Energetic Particles",
    year = "2017",
    journal = "Japan Geoscience Union",
    url = "https://www.semanticscholar.org/paper/54f04a883c67c44d19ce996f13c750b98b282615",
    is_oa = "true",
    openalex = "W7145382758",
    semanticscholar_id = "54f04a883c67c44d19ce996f13c750b98b282615"
}

@article{s2a779a7cae99d47724452359db41f425377519aa0,
    author = "Parker, E. and Forsythe, J. G. and Fernández, F.",
    title = "An Evaluation of the Prebiotic Plausibility of Depsipeptide Synthesis Under Possible Primitive Conditions",
    year = "2017",
    journal = "LPICo",
    url = "https://www.semanticscholar.org/paper/a779a7cae99d47724452359db41f425377519aa0",
    is_oa = "true",
    openalex = "W3028236448",
    semanticscholar_id = "a779a7cae99d47724452359db41f425377519aa0"
}

@incollection{nakazawa2018millerurey,
    author = "Nakazawa, Hiromoto",
    title = "“Miller–Urey Experiment” in the Recent Picture of the Early Earth",
    year = "2018",
    booktitle = "Advances in Geological Science",
    url = "https://doi.org/10.1007/978-981-10-8724-0\_4",
    doi = "10.1007/978-981-10-8724-0\_4",
    openalex = "W2806995174",
    pages = "55-73",
    references = "doi101038342139a0, doi10103835051550, doi10103835051557, doi10103838460, doi101038nature00995, doi101038nature03676, doi10106313067687, doi105962bhltitle59991, doi105962bhltitle82303, miller1953a"
}

<p>Motivated by the Miller-Urey experiment suggesting that lightning may have contributed to the origin of life on Earth through the formation of amino acids and carbonic acids, we here investigate the occurrence of electric discharges in the atmosphere of Primordial Earth. We focus on the early stages of lightning in the atmosphere of Primordial Earth, the so-called streamers, thin ionized plasma channels.</p><p>We study electron avalanches and potential avalanche-to-streamer transitions by modeling the motion of electrons with a particle-in-cell Monte Carlo code in gas mixtures of H<sub>2</sub>O:CH<sub>4</sub>:NH<sub>3</sub>:H<sub>2</sub>=37.5%:25%:25%:12.5% [S. L. Miller. Production of Some Organic Compounds under Possible Primitive Earth Conditions. Am. Chem. Soc., 77:9, pp. 2351-2361 (1955)] and N<sub>2</sub>:CO<sub>2</sub>:H<sub>2</sub>O:H<sub>2</sub>:CO=80%:18.89%:1%:0.1%:0.01% [J. F. Kasting. Earth’s Early Atmosphere. Science, 259:5097, pp. 920-926 (1993)] suggested for Primordial Earth approx. 3.8 Ga ago in different electric fields and for different levels of background ionization mimicking the photoionization process. We compare the evolution of the electron density,  electric field, and electron energies with those for Modern Earth. Finally, we will discuss which conditions favour streamer inception, as well as consequences for discharges on Primordial Earth.</p>

@article{doi105194egusphereegu20208384,
    author = "Enghoff, M. B. and Segkos, Nikolaos and Dujko, Saša and Chanrion, Olivier and Köhn, Christoph",
    title = "Streamer discharges in the atmosphere of Primordial Earth",
    year = "2020",
    abstract = "\<p\>Motivated by the Miller-Urey experiment suggesting that lightning may have contributed to the origin of life on Earth through the formation of amino acids and carbonic acids, we here investigate the occurrence of electric discharges in the atmosphere of Primordial Earth. We focus on the early stages of lightning in the atmosphere of Primordial Earth, the so-called streamers, thin ionized plasma channels.\</p\>\<p\>We study electron avalanches and potential avalanche-to-streamer transitions by modeling the motion of electrons with a particle-in-cell Monte Carlo code in gas mixtures of H\<sub\>2\</sub\>O:CH\<sub\>4\</sub\>:NH\<sub\>3\</sub\>:H\<sub\>2\</sub\>=37.5\%:25\%:25\%:12.5\% [S. L. Miller. Production of Some Organic Compounds under Possible Primitive Earth Conditions. Am. Chem. Soc., 77:9, pp. 2351-2361 (1955)] and N\<sub\>2\</sub\>:CO\<sub\>2\</sub\>:H\<sub\>2\</sub\>O:H\<sub\>2\</sub\>:CO=80\%:18.89\%:1\%:0.1\%:0.01\% [J. F. Kasting. Earth\&\#8217;s Early Atmosphere. Science, 259:5097, pp. 920-926 (1993)] suggested for Primordial Earth approx. 3.8 Ga ago in different electric fields and for different levels of background ionization mimicking the photoionization process. We compare the evolution of the electron density,\&\#160; electric field, and electron energies with those for Modern Earth. Finally, we will discuss which conditions favour streamer inception, as well as consequences for discharges on Primordial Earth.\</p\>",
    url = "https://doi.org/10.5194/egusphere-egu2020-8384",
    doi = "10.5194/egusphere-egu2020-8384",
    openalex = "W3091221176",
    references = "doi101016jgsf201707007, doi101038331612a0, doi101038342139a0, doi101103physrev57722, doi101126science11536547, doi101126science1161527, doi101126science1303370245, miller1953a, openalexw2026796374"
}

The origin of life was a cosmic event happened on primitive Earth. A critical problem to better understand the origins of life in Earth is to glimpse in which chemical scenarios the basic building blocks of biological molecules could be produced. Classic works in pre-biotic chemistry frequently considered early Earth as a homogeneous atmosphere constituted by chemical elements such as methane (CH4), ammonia (NH3), water (H2O), hydrogen (H2) and hydrogen sulfide (H2S). Under that scenario, Stanley Miller was capable to produce amino acids and solved the question about the origin of proteins. Conversely, the origin of nucleic acids has tricked scientists for decades as nucleotides are complex though necessary molecules to allow the existence of life. Here we review possible chemical scenarios that allowed not only the formation of nucleotides but also other significant biomolecules. We aim to provide a theoretical solution for the origin of biomolecules at specific sites named “Prebiotic Chemical Refugia”. A prebiotic chemical refugium should therefore be understood as a geographic site in prebiotic Earth on which certain chemical elements were accumulated in higher proportion than expected, facilitating the production of basic biomolecules. Plus, this higher proportion should not be understood as static, but dynamic; once the physicochemical conditions of our planet changed periodically. This different concentration of elements, together with geochemical and astronomical changes along days, synodic months and years provided somewhat periodic changes in temperature, pressure, electromagnetic fields, and conditions of humidity; among other features. Recent and classic works suggesting most likely prebiotic refugia on which the main building blocks of biological molecules might be accumulated are reviewed and discussed.

@misc{doi1020944preprints2021030341v1,
    author = "Prosdocimi, Francisco and de Farías, Sávio Torres and José, Marco V.",
    title = "Prebiotic Chemical Refugia: Multifaceted Scenario for the Formation of Biomolecules in Primitive Earth",
    year = "2021",
    booktitle = "Preprints.org",
    abstract = "The origin of life was a cosmic event happened on primitive Earth. A critical problem to better understand the origins of life in Earth is to glimpse in which chemical scenarios the basic building blocks of biological molecules could be produced. Classic works in pre-biotic chemistry frequently considered early Earth as a homogeneous atmosphere constituted by chemical elements such as methane (CH4), ammonia (NH3), water (H2O), hydrogen (H2) and hydrogen sulfide (H2S). Under that scenario, Stanley Miller was capable to produce amino acids and solved the question about the origin of proteins. Conversely, the origin of nucleic acids has tricked scientists for decades as nucleotides are complex though necessary molecules to allow the existence of life. Here we review possible chemical scenarios that allowed not only the formation of nucleotides but also other significant biomolecules. We aim to provide a theoretical solution for the origin of biomolecules at specific sites named \“Prebiotic Chemical Refugia\”. A prebiotic chemical refugium should therefore be understood as a geographic site in prebiotic Earth on which certain chemical elements were accumulated in higher proportion than expected, facilitating the production of basic biomolecules. Plus, this higher proportion should not be understood as static, but dynamic; once the physicochemical conditions of our planet changed periodically. This different concentration of elements, together with geochemical and astronomical changes along days, synodic months and years provided somewhat periodic changes in temperature, pressure, electromagnetic fields, and conditions of humidity; among other features. Recent and classic works suggesting most likely prebiotic refugia on which the main building blocks of biological molecules might be accumulated are reviewed and discussed.",
    url = "https://doi.org/10.20944/preprints202103.0341.v1",
    doi = "10.20944/preprints202103.0341.v1",
    openalex = "W3137278960",
    references = "crossref197933, doi101007bf00623322, doi1010160092867482904147, doi1010160092867483901174, doi101038nature08013, doi10108010409230490460765, doi101111j194551002000tb01518x, doi101126science1092464, doi101126science1653889131, doi101371journalpone0000563, doi1020944preprints2021030341v1, openalexw2040525210"
}