OBLITUARIES
Ricardo Guerrero Department of Microbiology, University of Barcelona, Spain E-mail: rguerrero@iecat.net	Joan Oró (1923-2004)

 

Joan (John, in English) Oró Florensa was born in Lleida, Catalonia, Spain, on October 26, 1923, the youngest of five children and the only male. Due to the Spanish Civil War (1936-1939), his graduation from high school was delayed until 1941. He then studied at the University of Barcelona, where he obtained his degree in Chemistry in 1947. Already as a child, young Oró was interested in the chemistry of life. Since at the time he entered university there were no studies in biochemistry in Spain, he decided to pursue a degree in chemistry and to focus on organic chemistry. After his graduation, he returned to his hometown, Lleida. There he tried first, unsuccessfully, to earn his living as a chemist; afterwards, he spent 3 years working at his father's bakery, saving money in case he had the opportunity to return to chemistry. Nevertheless, he had mixed feelings about what to do. Whereas he longed to start a career in biochemistry, and thought that he and his wife (Francesca Forteza, to whom he married in 1948) could make do with a small salary, they already had three children: Maria Elena, Joan and Jaume (the youngest son, David, was born when the family was already living in Houston). He knew that if he kept working in the bakery, he and his family would not have financial problems in the future. However, making such a decision would mean not working at what he enjoyed the most and in the field for which he had been trained. (Fig. 1)

He decided to take another risk and go to the United States. In 1951, through the Institute for North-American Studies in Barcelona, Oró made a list of more than fifty universities in the United States and sent letters to all of them requesting information. Four of the universities that answered his request offered him free tuition. He chose to enroll at the Rice Institute in Houston, Texas. Oró arrived in Houston on August 2, 1952, to start his graduate studies in chemical engineering. A few months later, he met Donald Rappoport, who was Professor of Biochemistry at Baylor College of Medicine, and needed a graduate student to help him in his research on metabolism. The study in which Oró participated was aimed at elucidating some of the features of rapidly dividing, healthy cells in order to better understand the biology of cancer cells.

Oró studied the incorporation of carbon-labeled formate into animal tissues and the fate of this compound. He discovered that a major portion of the formate metabolized by sections of jejunum was incorporated into serine, cystathionine, and other acid-soluble products, and another portion was oxidized to CO₂ by a catalase-hydrogen peroxide complex. Based on that work, Oró demonstrated that molecules essential for life can be synthesized from other very simple ones, as was the case of formate, which has only one carbon. By mid-1955, Oró had finished the experimental part of his doctoral thesis and thought that he would be ready to defend it in a few months. The Dean of Baylor School of Medicine recommended, however, that he waited until 1956; otherwise people might have the impression that doctorates could be obtained quickly at that school. While completing his thesis, Oró taught as an instructor in the Department of Chemistry of the University of Houston. He had to work very hard to cope with the five subjects he had to teach in addition to writing his doctoral thesis, which was not easy since he was not yet fluent in English.

At the Department of Chemistry of the University of Houston, Oró worked successively as Assistant Professor (1956-1958) and Associate Professor (1958-1963) before being appointed Full Professor, in 1963. By then he had already achieved one of his major goals in research: synthesizing adenine under laboratory conditions. Having obtained amino acids from hydrogen cyanide, water, and ammonia (the results of this experiment were not published until 1960), he then focused on the synthesis of adenine from glycine and several simple compounds. A student of his started the experimental work, which soon seemed to demonstrate the production of large amounts of adenine. Oró thought that such yields must be almost impossible to obtain and checked the results, only to realize that the graph that the student had interpreted as adenine in fact corresponded to the solvent that had been used. Remembering his earlier results, Oró considered the possibility of synthesizing adenine from ammonium cyanide. In fact, chromatography had shown a small spot corresponding to adenine. Perhaps he would be able to increase the adenine yield by using more nitrogen cyanide. On Christmas Eve, 1959, he concentrated a mixture of the starting ingredients and then allowed the solution to stand overnight. The following morning, when he returned to the lab, chromatographic analysis revealed a large black spot, which under ultraviolet light was confirmed to be adenine. He had done it! This experiment opened a new field of research that eventually led to the laboratory synthesis of the rest of the components of nucleic acids.

The most amazing conclusion Oró drew from that result was that a molecule essential for life, such as adenine, could be synthesized from ammonium cyanide, which is a lethal compound for respiration. Melvin Calvin (Chemistry Nobel Prize winner for his work on the mechanisms of photosynthesis in 1961) was among the first to recognize the significance of Oro's experiment and invited him to join his team at the Lawrence Radiation Laboratory of the University of California-Berkeley in the summer of 1962. Oró did not accept, choosing instead to stay in Houston.

In 1961, Oró suggested that cometary collisions with the Earth might have contributed to increasing the amount of carbon compounds in the early planet, thus promoting the prebiotic synthesis of biochemical molecules. He also suggested that comets had brought water to Earth. In fact, even if the young planet Earth was assumed to have had water, it probably escaped to outer space along with some mass of the planet as a result of a collision with a body the size of Mars. Later calculations showed that the amount of carbonaceous matter that reached the Earth as a result of cometary collisions might have been as large as 10¹² grams.

In 1963, Freeman Quimby, who chaired the Life Sciences Department at NASA, invited Oró to join the group that would work on organic chemistry studies of the Apollo project. He was the Principal Researcher of the Houston University team that collaborated in the project and which had developed equipment for chemically analyzing lunar samples, both in situ-on the Moon-and in the laboratory-once the samples had been taken back to the Earth. The two scientists developed a small portable mass spectrometer that could analyze low-molecular-weight molecules. Even though that device was not used on the Moon, it was the basis for the mass spectrometer used in another NASA mission, the Viking project to Mars. Participation in the Apollo project made it possible for Oró's laboratory at the University of Houston to obtain state-of-the-art equipment for carrying out molecular analyses, for example, an apparatus combining mass spectrometry and gas chromatography that was crucial for meticulous analyses of complex mixtures. The study of lunar samples confirmed what many scientists had already suspected for years: there was no life on the Moon.

On July 20, 1976, the first Mars lander reached the surface of the red planet. Of the more than a dozen experiments carried out on Mars with the help of a robot, three dealt with biology. The most important consisted of mixing a sample of Martian soil with a solution that contained nutrients labeled with ¹⁴C, including glucose and several simple amino acids such as glycine. Biologists were amazed to learn that the mixture produced a large quantity of ¹⁴C-labeled carbon dioxide. Oró, however, had felt from the very beginning that life would not be discovered on the Mars surface because of the high degree of oxidation, and was skeptical of the interpretation of the results. When he discovered that formic acid was among the components of the test solution, he had an explanation for the result. He was familiar with the mechanisms of oxidation of formic acid, which he had studied as part of his doctorate. Formic acid oxidation is a common chemical, non-biological reaction.

Oró participated in the NASA Program of Organic Cosmochemistry until his retirement in 1994, studying organic synthesis under early Earth conditions and analyzing samples of meteorites, ancient rocks, and fossils. Before his retirement, and even afterwards, Oró was committed to the world of research both in the United States and in Catalonia. He chaired the first meeting of the International Society for the Study of the Origin of Life (ISSOL), which was held in Barcelona in 1973, and as the President of ISSOL was also one of the organizers of the seventh edition of the same meeting, which also took place in Barcelona, in 1993, under the direction of the author of this article. He participated in founding the Association of Friends of Gaspar de Portolà (which promotes academic and cultural ties between California and Catalonia, mainly through a scholarship program), as well as the Catalan Foundation for Research, whose mission is to further scientific research in Catalonia. In Lleida, his hometown, he set up his own foundation (Fundació Joan Oró), whose aim is to promote basic and applied research as well as ties between companies and universities and research centers.

In 1994, Oró retired from his academic and research duties at the University of Houston and returned to Catalonia. His wife Francesca (Paquita) had died in 1990, and in 1995 he married to Antonieta Vilajoliu, from Balaguer, Lleida, who was also a widow of a late friend of Oró.

Oró's final project was an ambitious one. He had always longed for Catalonia to have a first-class Center of Astrophysics in the Montsec (between Barcelona and Lleida), where the sky is clear and there is scarcely any light contamination. An astronomic and meteorologic study carried out by researchers of the University of Barcelona confirmed that, in fact, the village of Sant Esteve de la Farga, in the Montsec, was among the best locations in Catalonia to build an observatory. The project, currently under way, like Oro's other endeavors and accomplishments has a three-fold aim: research, education, and the dissemination of science.

The prestige of Oró transcended the scientific community in Catalonia and Spain, as evidenced by the recognition he received from universities, political institutions, and the general public. In Spain, Oró was granted honorary degrees from the Universities of Granada (1972) and Lleida (1999); was an honorary member of several scientific societies; and received many awards, including the Gold Medal of the city of Lleida (1976), the Narcís Monturiol Medal for Scientific and Technological Merit (1982), the Grand Cross of the Order of Aeronautical Merit (1983), the President Francesc Macià Labor Medal (2000), the Gold Medal for Scientific Merit of the City Council of Barcelona (2002), and the Gold Medal of the Generalitat de Catalunya (2004). On 23 June 2003 the King of Spain awarded him with the title of Marquise of Oró for his continuous dedication to the scientific world through his many research works, which "have contributed, in a remarkable way, to improve the knowledge of the origin of life." For his arms, Oró chose the adenine formula, surely the first molecule represented on a coat of arms in the history of heraldry.

It is always difficult to summarize the work and accomplishments of an extraordinary scientist; and Professor Joan Oró was one of those rare persons. But we can try to do so by listing some of the major discoveries from the 30 years of research carried out under his direction.

The first prebiotic synthesis of adenine from hydrogen cyanide was accomplished during the period 1959-1962 (Fig. 2). Adenine is probably the most important biological molecule because of its key role as an essential component of DNA, ATP, and other biological molecules responsible for the genetic code, replication, enzymatic catalysis, and metabolism in all living systems. This work opened up an area of research that led to the complete synthesis of all components of nucleic acids. In 1961, Oró suggested that cometary collisions with the primitive Earth had contributed substantial amounts of carbon-containing compounds for the prebiotic synthesis of biochemical molecules. Later computations (1980-1982) showed that the amount of carbonaceous matter acquired by the primitive Earth from comets was probably of the order of 10²³ grams. This is 100,000 times larger than the total mass of the present biosphere and accounts for the disappearance of the bulk of the Earth's primary atmosphere as a result of a collision with a Mars-sized body, which led to the evaporation of all the volatiles and the formation of the Moon (Earth-Moon system).

Beginning in 1958, Oró developed and applied new chromatography-mass spectrometry methods to the analysis of organic compounds synthesized under plausible primitive Earth conditions or present in extraterrestrial samples, such as meteorites and lunar samples. He was the first to analyze volatile amino-acid derivatives by applying these methods. In 1970, using optically active phases, he was also the first to detect D- and L-amino enantiomers in carbonaceous chondrites. This led to work by Kvenvolden and collaborators suggesting that organic compounds were chemically synthesized on meteorite parent bodies more that 4.5 × 10⁹ years ago, when the solar system was formed.

From 1964 to 1977, Oró designed, developed, and tested an instrument for analyzing the atmosphere and surface volatile components of the planet Mars. He suggested the building of a new miniaturized gas chromatograph-mass spectrometer for the Viking mission to Mars. Four instruments of this type were built and integrated into four Viking Mars landers. Two of these spacecrafts were sent to Mars in 1976, and provided the first analysis of the atmosphere and surface of another planet. A complete analysis of the atmosphere and volatile surface components was eventually obtained but no organic compounds were found on Mars.

In 1976, Oró offered a chemical interpretation of the puzzling results obtained by other scientists concerning the presence of life on Mars. Based on his previous work from 1956, Oró was able to explain that the sudden and intense production of ¹⁴CO₂ by the Martian soil samples in the Viking test chamber was not due to the rapid metabolism of presumed Martian microorganisms, but rather to the catalytic chemical oxidation of the test nutrients, especially formic acid, labeled with ¹⁴C by iron and other active oxides present in the Martian samples. The absence of evidence for life on Mars stopped the development of plans by NASA for subsequent manned exploration of the red planet.

During 1978-1980, Oró demonstrated the photocatalytic oxidation of organic compounds under simulated Martian conditions. The results showed that any organic matter present on the surface of the red planet that had been exposed to ultraviolet radiation from the Sun would have a very short lifetime, being oxidized to CO₂ and H₂O. This provided an explanation for the surprising absence of organic compounds on the Martian surface and additional evidence in support of the absence of life on Mars.

In 1963, Oró was the first to suggest that the synthesis of biological macromolecules, such as polypeptides and polynucleotides, could be carried out by means of condensing agents, such as cyanamide and imidazole derivatives. Indeed, this was demonstrated in many subsequent experiments that were carried out in Oró's laboratory at the University of Houston. Cyanamide is present in the interstellar medium, where it is an important organic molecule. During the years 1982-1984, many imidazole derivatives were synthesized in Oró's laboratory under possible primitive Earth conditions.

From 1978 to 1984, Oró's laboratory was able to synthesize most of the phospholipid components of cellular membranes, including phosphatidylcholine and phosphatidylethanolamine. Using such amphiphilic molecules, it was possible to obtain liposome vesicles similar to the membranes of most living cells, thereby demonstrating for the first time how the membranes of living organisms might have formed.

In the 1980s, Oró's laboratory carried out the prebiotic synthesis of histidine, histidyl-histidine, and a number of phosphorylated coenzymes and other enzymatically active compounds. Protocellular models involving liposomes and catalytically active RNA molecules were developed theoretically. Current experiments are testing the validity of these models.

Oró finally returned to Spain in 1994, after his retirement from the University of Houston. During the following 10 years he devoted his energies and attention to science and culture in his home country, Catalonia. Joan Oró died in the city of Barcelona on September 2, 2004, mourned by his second wife and four children. However, his work continues to motivate and inspire. Today, even though the riddle of the origin of life is still far from being solved, it has lost most of its shroud of mystery and is beginning to be understood in molecular terms-thanks to the intelligence and effort of outstanding scientists such as Professor Joan Oró.

Acknowledgements. I acknowledge Mercè Piqueras for her help in the editing of Prof. Oró's bibliography, which we received from Prof. Oró himself in 2003.

Selected articles by Joan Oró

Oró J. (1956). ¹⁴C-Formate Metabolism in Animal Tissues with Special Reference to the Mechanism of Formic Acid Oxidation (Doctoral thesis). Baylor University College of Medicine, Houston

Oró J., D.A. Rappoport (1957). Formate metabolism by animal tissues, I. Metabolism of formate-¹⁴C by isolated rabbit and rat jejunum. J. Biol. Chem. 224:489-498

Oró J, A. Kimball, R. Fritz, F. Master (1959) Amino acid synthesis from formaldehyde and hydroxylamine. Arch. Biochem. Biophys. 85:115-130

Oró J. (1960) Synthesis of adenine from ammonium cyanide. Biochem. Biophys. Res. Commun. 2:407-412

Oró J. (1961). Comets and the formation of biochemical compounds on the primitive Earth. Nature 190:389-390

Oró J., S.S. Kamat (1961) Amino acid synthesis from hydrogen cyanide under possible primitive Earth conditions. Nature 190:442-443

Oró J., A.P. Kimball (1961) Synthesis of purines under possible primitive Earth conditions. I. Adenine from hydrogen cyanide. Arch. Biochem. Biophys 94:217-227

Oró J. (1961). Mechanism of synthesis of adenine from hydrogen cyanide under possible primitive Earth conditions. Nature 191:1193-1194

Oró J., A.P. Kimball (1962). Synthesis of purines under possible primitive Earth conditions, II. Purine intermediates from hydrogen cyanide. Arch. Biochem. Biophys. 96:293-313

Oró J. (1963). Ultra-violet-absorbing compounds(s) reported present in the Murray meteorite. Nature 197:756-758

Oró J. (1963). Synthesis of organic compounds by electric discharges. Nature 197:862-867

Oró J. (1963). Synthesis of organic compounds by high energy electrons. Nature 197:971-974

Oró J., D.W. Nooner, A. Zlatkis, S.A. Wikström, E.S. Barghoorn (1965). Hydrocarbons of biological origin in sediments about two billion years old. Science 148:77-79

Oró J., T. Tornabene (1965). Bacterial contamination of some carbonaceous meteorites. Science 150:1046-1048

Oró J., J. Han (1966). High temperature synthesis of aromatic hydrocarbons from methane. Science 153:1393-1395

Oró J., D.W. Nooner (1967). Aliphatic hydrocarbons in pre-Cambrian rocks. Nature 213:1082-1085

Oró J., D.W. Nooner (1967). Aliphatic hydrocarbons in meteorites. Nature 213:1085-1087

Oró J., T.G. Tornabene, D.W. Nooner, E. Gelpi (1967). Aliphatic hydrocarbons and fatty acids of some marine and freshwater microorganisms. J. Bacteriol. 93:1811-1818

Tornabene T.G., E. Gelpi, J. Oró (1967). Identification of fatty acids and aliphatic hydrocarbons in Sarcina lutea by gas chromatography and combined gas chromatography-mass spectrometry. J. Bacteriol. 94:333-343

Tornabene T.G., E.O. Bennett, J. Oró (1967). Fatty acid and aliphatic hydrocarbon composition of Sarcina lutea grown in three different media. J. Bacteriol. 94:344-348

Tornabene T.G., J. Oró (1967). ¹⁴C Incorporation into the fatty acids and aliphatic hydrocarbons of Sarcina lutea. J. Bacteriol. 94:349-358

Oró J., E. Gelpi, D.W. Nooner (1968). Hydrocarbons in extraterrestial samples. J. Br. Interplan. Soc. 21:83-98

Gelpi E., J. Oró, H.J. Schneider, E.O. Bennett (1968). Olefins of high molecular weight in two microscopic algae. Science 161:700-702

Gelpi E., D.W. Noonerk, J. Oró (1969). Isoprenoids and other hydrocarbons in terrestrial gaphite. Geochim. Cosmochim. Acta 33:959-972

Tornabene T.G., M. Kates, E. Gelpi, J. Oró (1969). Occurrence of squalene, di-and tetrahydrosqualenes, and vitamin MK₈ in an extremely halophilic bacterium, Halobacterium cutirubrum. J. Lipid Res. 10:294-303

Simmonds P.G., A.J. Bauman, E.M. Bollin, E. Gelpi, J. Oró (1969). The unextractable organic fraction of the Pueblito de Allende meteorite: Evidence for its indigenous nature. Proc. Natl. Acad. Sci. USA 64:1027-1034

Gelpi E., H. Schneider, J. Mann, J. Oró (1970). Hydrocarbons of geochemical significance in microscopic algae. Phytochemistry 9:603-612

Schneider H., E. Gelpi, E.O. Bennett, J. Oró (1970). Fatty acids of geochemical significance in microscopic algae. Phytochemistry 9:613-617

Nakaparksin S., P. Birrell, E. Gil-Av, J. Oró (1970) Gas chromatography with optically active stationary phases: Resolution of amino acids. J. Chromat. Sci. 8:177-182

Gibert J.M., J. Oró (1970). Gas chromatographic-mass spectrometric determination of potential contaminant hydrocarbons of Moon samples. J. Chromat. Sci. 8:295-296

Oró J., W.S. Updegrove, J. Gibert, J. McReynolds, E. Gil-Av, J. Ibanez, A. Zlatkis, D.A. Flory, R.L. Levy, C. Wolf (1970). Organogenic elements and compounds in surface samples from the Sea of Tranquillity. Science 167:765-767

Levy R.L., C.J. Wolf, M.A. Grayson, J. Gilber, E. Gelpi, W.S. Updegrove, A. Zlatkis, J. Oró (1970). Organic analysis of the Pueblito de Allende meteorite. Nature 227:148-150

Segura R., J. Oró, A. Zlatkis (1970). Resolution of steroid glucuronides by thin-layer chromatography on polyamide. J. Chromatogr. Sci. 8:449-451

Gibert J., D. Flory, J. Oró (1971). Identity of a common contaminant of Apollo 11 Lunar fines and Apollo 12 York meshes. Nature 229:33-34

Oró J., J. Gibert, H. Lichtensteink, S. Wikstrom, D.A. Flory (1971). Amino acids, aliphatic and aromatic hydrocarbons in the Murchison meteorite. Nature 230:105-106

Oró J., S. Nakaparksin, H. Lichtenstein, E. Gil-Av (1971). Configuration of amino-acids in carbonaceous chondrites and a pre-Cambrian chert. Nature 230:107-108

Stephen-Sherwood E., J. Oró, A.P. Kimball (1971). Thymine: A possible prebiotic synthesis. Science 173:446-447

Wolman Y., S.L. Miller, J. Ibanez, J. Oró (1971). Formaldehyde and ammonia as precursors to prebiotic amino acids. Science 174:1039-1040

Nooner D.W., J. Oró; J.M. Gibert,V.L. Ray, J.E. Mann (1972). Ubiquity of hydrocarbons in nature: Aliphatic hydrocarbons in weathered limestone. Geochim. Cosmochim. Acta 36:953-959

Oró J. (1972). Extraterrestrial organic analysis. Space Life Sci. 3:507-550.

Doctor V.M., J. Oró (1972). Non-enzymic β-decarboxylation of aspartic acid. J. Mol. Evol. 1:326-333

Macdonald E.J., H. Lichtenstein, D. Nooner, D. Flory, S. Wikstrom, J. Oró (1973). Epidemiological factors in lung cancer among women in El Paso County, Texas, 1944-1969. J. Am. Med. Women's Assoc.28:459-467

Nooner D.W, W.S. Updegrove, D.A. Flory, J. Oró, G. Mueller (1973). Isotopic and chemical data of bitumens associated with hydrothermal veins from Windy Knoll, Derbyshire, England. Chem. Geol.11:189-202

Nooner D.W., J. Oró, J. Cerbulis (1973). Paraffinic hydrocarbon composition of earthworms (Lumbricus terrestris). Lipids 8:489-492

Nooner D.W., J. Oró (1974). Direct synthesis of polypeptides. Polycondensation of α-amino acids by polymetaphosphate esters. J. Mol. Evol. 3:79-88

Nissenbaum A., D.H. Kenyon, J. Oró (1975). On the possible role of organic melanoidin polymers as matrices for prebiotic activity. J. Mol. Evol. 6:253-270

Holzer G., J. Oró, W. Bertsch (1976). Gas chromatographic-mass spectrometic evaluation of exhaled tobacco smoke. J. Chromatogr. 126:771-785

Biemann K., J. Oró, P. Toulmin III, L.E. Orgel, A.O Nier, D.M. Anderson, P.G. Simmonds, D. Flory, A.V. Diaz, D.R. Rushneck, J.A. Biller (1976). Search for organic and volatile inorganic compounds in two surface samples from the Chryse Planitia region of Mars. Science 194:72-76

Biemann K., J. Oró, P. Toulmin III, L.E. Orgel, A.O. Nier, D.M. Anderson, P.G. Simmonds, D. Flory, A.V. Díaz, D.R. Rushneck, J.E. Biller, A.L. Lafleur (1977). The search for organic substances and inorganic volatile compounds in the surface of Mars. J. Geophys. Res. 82:4641-4658

Holzer G, J. Oró (1977). Pyrolysis of organic compounds in the presence of ammonia. The Viking Mars lander site alteration experiment. Org. Geochem. 1:37-52

Tornabene T.G, R.S. Wolfe, W.E. Balch, G. Holzer, G.E. Fox, J. Oró (1978). Phytanyl-glycerol ethers and squalenes in the Archaebacterium Methanobacterium thermoautotrophicum. J. Mol. Evol. 11:259-266

Tornabene T.G., T.A. Langworthy, G. Holzer, J. Oró (1979). Squalenes, phytanes and other isoprenoids as major neutral lipids of methanogenic and thermoacidophilic "Archaebacteria". J. Mol. Evol.13:73-83

Holzer G., J. Oró (1979). The organic composition of the Allan Hills carbonaceous chondrite (77306) as determined by pyrolysis-gas chromatography-mass spectrometry and other methods. J. Mol. Evol. 13:265-270

Oró J., G. Holzer (1979). The photolytic degradation and oxidation of organic compounds under simulated Martian condition. J. Mol. Evol.14:153-160

Deamer D.W., J. Oró (1980). Role of lipids in prebiotic structures. Biosystems 12:167-175

Rao M., D.G. Odom, J. Oró (1980). Clays in prebiological chemistry. J. Mol. Evol. 15:317-331

Holzer G., J. Oró, S.J. Smith, V.M. Doctor (1980). Separation of monosaccharides as their alditol acetates by capillary column gas chromatography. J. Chromatogr. 194:410-415

Giner-Sorolla A., J. Oró (1981). Mutagens and carcinogens: Occurrence and role during chemical and biological evolution. In: Wolman Y. (ed.) Origins of Life. Reidel, Dordrecht, 583-588

Hawker J.R. Jr., J. Oró (1981). Cyanamide mediated synthesis of peptides containing histidine and hydrophobic amino acids. J. Mol. Evol.17:285-294

Bar-Nun A., A. Lazcano-Araujo, J. Oró (1981). Could life have evolved in cometary nuclei? Orig. Life 11:388-394

Rao M., J. Eichberg, J. Oró (1982). Synthesis of phosphatidylcholine under possible primitive Earth conditions. J. Mol. Evol. 18:196-202

Oró J., K. Rewers, D. Odom (1982). Criteria for the emergence and evolution of life in the Solar system. Orig. Life 12:285-305

Odom, D., T. Yamrom, J. Oró (1983). Prebiotic oligodeoxynucleotide synthesis in a cyclic evaporating system at low temperatures. Adv. Space Res. 3:55-59

Bada J.L., J.R. Cronin, M-S. Ho, K.A. Kvenvolden, J.G. Lawless, S.L. Miller, J. Oró, S. Steinberg (1983). On the reported optical activity of amino acids in the Murchison meteorite. Nature 301:494-497

Basile B.P, B.S. Middleditch, J. Oró (1984). Polycyclic aromatic hydrocarbons in the Murchison meteorite. Org. Geochem. 5:211-216

Yuasa S., D. Flory, B. Basile, J. Oró (1984). Abiotic synthesis of purines and other heterocyclic compounds by the action of electrical discharges. J. Mol. Evol. 21:76-80

Baeza I., M. Ibañez, J.C. Santiago, C. Wong, A. Lazcano, J. Oró (1986). Studies on precellular evolution: The encapsulation of polyribonucleotides by liposomes. Adv. Space Res. 6:39-43

Mar A., J. Dworkin, J. Oró (1987). Non-enzymatic synthesis of the coenzymes, uridine diphosphate glucose and cytidine diphosphate choline, and other phosphorylated metabolic intermediates. Orig. Life 187:307-319

Lazcano A., J. Fastag, O. Gariglio, C. Ramirez, J. Oró (1988). On the early evolution of RNA polymerase. J. Mol. Evol. 27:365-376

Lazcano A., R. Guerrero, L. Margulis, J. Oró (1988). The evolutionary transition from RNA to DNA in early cells. J. Mol. Evol. 27:283-290

Oró J., T. Mills (1989). Chemical evolution of primitive Solar system bodies. Adv. Space Res. 9:105-120

Shen C., L. Yang, S.L. Miller; J. Oró (1990). Prebiotic synthesis of histidine. J. Mol. Evol. 31:175-179

Shen C., T. Mills, J. Oró (1990). Prebiotic synthesis of histidyl-histidine. J. Mol. Evol.31:175-179

Shen, C., A. Lazcano, J. Oró (1990). The enhancement effects of histidyl-histidine in some prebiotic reactions. J. Mol. Evol. 31:445-452

Mar A., J. Oró (1991). Synthesis of the coenzymes adenosine diphosphate glucose, guanosine diphosphate glucose, and cytidine. Diphosphoethanolamine under primitive Earth conditions. J. Mol. Evol. 32:201-210

Wong C., J.C. Santiago, L. Rodríguez-Páez, M. Ibáñez, I. Baeza, J. Oró (1991). Synthesis of putrescine under possible primitive Earth conditions. Orig. Life Evol. Biosph. 21:145-156

Oró J., T. Mills, A. Lazcano (1992). The cometary contribution to prebiotic chemistry. Adv. Space Res. 12:33-41

Velasco A.M., L. Medrano, A. Lazcano, J. Oró (1992). A redefinition of the Asp-As

J. Mol. Evol. 35:551-556

Baumann U., J. Oró (1993). Three stages in the evolution of the genetic code. BioSystems 29:133-141

Oró J. (1994). Chemical synthesis of lipids and the origin of life. J. Biol. Phys. 20:135-147

Oró J., T. Mills, A. Lazcano (1995). Comets and life in the Universe. Adv. Space Res. 15:81-90

Oró, J. (1995). Cosmochemical evolution and the origin of life. Microbiol. SEM 11:145-160

Macià E., V. Hernandez; J. Oró (1997). Primary sources of phosphorus and phosphates in chemical evolution. Orig. Evol. Biosph. 27:459-480

Levy. M., S.L. Miller, J. Oró (1999). Production of guanine from NH₄CN polymerization. J. Mol. Evol. 49:165-169

Oró J. (2002). Historical understanding of life's beginnings. In: Schopf J. W. (ed.) Life's Origin. The Beginnings of Biological Evolution. University of California Press, Berkeley, pp.7-45

 

The complete list of articles, chapters of books, books and doctoral theses
directed by Prof. Joan Oró can be found in the online version of this article.
See: [www.im.microbios.org], March 2005 issue.