Cyril Ponnamperuma: An Incisive Scientific Researcher ….. In World Class

Sachi Sri Kantha

This is an updated version of a manuscript, previously submitted to the Ceylon Medical Journal in 1996. It was rejected for publication by the then editorial team. I was not informed of any specific reason for rejection, by the then co-editor Prof. Colvin Goonaratna. My perception was, lack of a medical qualification by Prof. Cyril Ponnamperuma, could have been one reason. I also provide a rare NASA photo of Prof Ponnamperuma with Soviet biochemist Alexander Oparin (1894-1980), probably taken in October 1963, when the latter visited Florida for a conference.

Abstract:; Ceylon-born cosmobiochemist Cyril Ponnamperuma’s birth centenary passed by last year. This year, marks the 30^th anniversary of his death. I provide a brief review of his career accomplishments. After receiving initiation as a researcher at the Laboratory of Melvin Calvin, the 1961 Nobel laureate in chemistry, Cyril Ponnamperuma investigated the origin of life by two experimental approaches. First was the synthetic approach, in which primordial life-sustaining organic molecules were synthesized in the lab under simulated conditions. Second was the analytical approach, in which organic matter from ancient rocks on the Earth and extraterrestrial bodies such as moon, meteorites and Mars were analyzed for primordial, biologically important organic molecules. He remains one of the most prolific scientists of Sri Lanka.

Background

Cyril Ponnamperuma, one of the internationally acclaimed scientists born in Sri Lanka, died on Dec 20, 1994, after suffering a cardiac arrest in his university office. [1-3]. Born on Oct. 16, 1923 at Galle, Ponnamperuma received his early training in science in Sri Lanka, India and Britain, before establishing his reputation in the USA. According to biographical records assembled from more than one source, Ponnamperuma received his first bachelor’s degree in philosophy (due to persuasion from his parents) from the University of Madras (now, Chennai) in 1948. It was not uncommon in 1940s and 1950s for student from Ceylon to earn their first degree from the University of Madras. Following graduation, he returned to Ceylon and taught science at secondary high school for few years. Ponnamperuma got married to Valli Pal in 1955, and they had a daughter Roshini. Then he left for London and earned his B.Sc degree at Birkbeck College, University of London in 1959, at a relatively mature age of 36 years. It was in London, he was influenced by the great polymath John Desmond Bernal (1901-1971).

In his interview to the OMNI magazine, Ponnamperuma had reminisced: ‘I had the fortune to meet a remarkable man named J.D. Bernal. He taught us physics, and once, instead of giving us a lecture on electricity and magnetism, he spoke about the origins of life. And that’s the first time I learned that one could do experimental work on the origins of life.’ [4] Ponnamperuma then crossed the Atlantic and landed in California to join the laboratory of Melvin Calvin (1911-1995) at the University of California, Berkeley in 1959. His first appointment was as a research associate at the Lawrence Radiation Lab in 1960. He was awarded a Ph.D from the University of California, Berkeley, in 1962 for the work done under the guidance of Melvin Calvin, who by then had been honored with the 1961 Nobel prize in chemistry. Ponnamperuma’s 123 page dissertation was entitled, ‘The radiation chemistry of nucleic acid constituents’. It is not inappropriate to state that Ponnamperuma was lucky to be in the right place at the right time.

Following his doctorate, Ponnamperuma joined the National Aeronautic Space Administration (NASA), Ames Research Center at Moffett Field, California in 1962 and remained there till 1970, ultimately directing the Chemical Evolution program at that Center. That was the time when the NASA represented the ‘frontier spirit’ of American exploration and Ponnamperuma’s expertise was in demand as well. Since 1971, till his death, he served as the professor of chemistry and biochemistry at the University of Maryland, College Park.

Research on the Origin of Life

Ponnamperuma established his reputation as a cosmobiochemist between 1961 and 1966 in a dozen papers, all excluding one appeared in the prestigious journals, Nature and Science. He was the primary author in all these papers. Three of these papers had Calvin, his thesis advisor, as one of the co-authors. Another two papers merit recognition in having the popularly known astrophysicist Carl Sagan as one of the co-authors. Ponnamperuma employed different approaches to study the origin of life.

1. Synthetic Approach

In 1961, Ponnamperuma et al. [5] reported the formation of small amount of hypoxanthie when adenine solution was irradiated with Co⁶⁰ source. The radiation intensity was 5 x 10⁶ rad/hr. They concluded that “because hypoxanthine, xanthine and uracil normally exist in the keto form, the deamination of adenine to hypoxanthine will result in the disruption of the hydrogen bonding between adenine and thymine, suggested by the Watson and Crick structure of DNA”. Following year, Ponnamperuma et al.[6] demonstrated the formation of uracil and the breakdown of the pyrimidine ring due to irradiation of an aqueous solution of cytosine.

By 1963, Ponnamperuma et al.[7] established that adenine is converted to adenosine by uv radiation in the presence of phosphoric acid or polyphosphate ester. They made two inferences:

• “The formation of adenosine by a relatively simply abiological process is significant in the context of the gradual evolution of life on this planet over a period of several hundred million years. The result is all the more striking as similar simple processes are effective in the production of nucleoside phosphates.”
• “This result may possibly confer a unique role on phosphorus in the evolution of compounds of biological significance.”

In a subsequent paper published in the same year, Ponnamperuma et al. (8) demonstrated the conversion of adenine into adenosine, adenosine to adenosine monophosphate, adenosine monophosphate to adenosine diphosphate and adenosine diphosphate to adenosine triphosphate. The third paper from Ponnamperuma’s group (9) in 1963 reported additional interesting information on the origin of biologically important molecules. These included the following:

• Electron irradiation of a mixture of methane, ammonia and water resulted in the formation of adenine.
• An inverse relationship exists between the amount of adenine synthesis and the amount of hydrogen gas present.
• Under prebiotic conditions, adenine (but not guanine, cytosine, uracil or thymine) is most readily synthesized.

In the following years, Ponnamperuma’s team demonstrated the synthesis of.

• C₆ to C₉ hydrocarbons from gaseous methane. (10, 11)
• Deoxyadenosine from adenine and deoxyribose with the use of HCN and uv light. (12)
• Guanine from a mixture of glutamic acid, aspartic acid and equimolar mixture of remaining 16 aminoacids. (13)
• Dipeptides and tripeptides from an aqueous solution of glycine and leucine. (14)
• Nucleoside monophosphates from nucleosides (adenosine, guanosine, cytidine, uridine and thymidine) heated with inorganic phosphate. (15)

By current standards of instrumentation, the experimental methods used by Ponnamperuma in early 1960s seems simple and somewhat crude. Paper chromatography, thin-layer chromatography, ion-exchange chromatography, autoradiography and uv lamps were the tools used by his group during that period. (16-20)

2. Analytic Approach

The Murchison meteorite which fell near Murchison, Victoria, Australia on September 28, 1969 was analyzed by Ponnamperuma’s group [21, 22] and they demonstrated that the fragments analyzed had carbon (2.0% by wt) and nitrogen (0.16% by wt). Organic analysis turned out to be positive of aminoacids (glycine, alanine, valine, proline, glutamic acid and aspartic acid) and aliphatic hydrocarbons.

‘The Moon issue’ of the Science journal (Jan 30 1970) presented 143 studies made on the 22 kg of lunar materials brought back by the Apollo 11 mission. Ponnamperuma was the primary author in one of these studies, which had a total of 18 authors. (23) They examined the lunar dust for total carbon, organic carbon, isotope fragments, microfossils and minerals using ion exchange (H⁺), aminoacid analysis, gas liquid chromatography, thin layer chromatography, spectrometry, silica gel chromatography, magnetic circular dichroism and spectrofluorometry. The analysis of Ponnamperuma et al. (24) revealed that the concentration of carbon to be about 157 mg/g sample. Ponnamperuma was also a co-author of another published in this special issue of the Science. (24) In summarizing the results of his investigations on moon rocks, Ponnamperuma had stated: “We examined fractions of every lunar sample that was brought back from Apollo 11 through Apollo 17. We made an extensive search for traces of organic material that might be indicative of chemical evolution. We found about 200 ppm of organic matter, but no evidence of aminoacids, no evidence of any molecules of organic significance.” (25)

Due to the difficulty of obtaining test samples from other planets such as Mars and Jupiter, Ponnamperuma’s team also performed simulation experiments. (26-30) In a popular article entitled ‘Life on Jupiter’, Ponnamperuma and Molton (30) noted that when they exposed four species of common terrestrial microorganisms (three bacteria and one yeast) to pressures ranging from 0.1 to 120 atmospheres, to simulate the Jovian atmosphere for a day, at temperature of 30 to -200^oC, they observed survival of miroorganisms in ‘nearly all cases’, suggesting the possibility of presence of indigenous Jovian life. Ponnamperuma’s ideas, experimental studies and theoretical postulations on the origin and meaning of lie (27, 28) as well as life on Mars and Jupiter (28, 29) have also been published in readable reviews.

Productivity

Usually in the USA, budding scientists publish their first paper around the age of 25. Ponnamperuma was somewhat handicapped since he received his PhD, at the age of 39 years, and his first paper of some merit appeared only when he was 38. Despite this handicap, he contributed significantly to the development of cosmobiochemistry (a field in which he had eminent peers like Harold Urey, Fred Hoyle, Leslie Orgel, Francis Crick, Stanley Miller and Carl Sagan) for almost 35 years. Amidst such peer pressure, Ponnamperuma was highly productive. His interview with William Hagan on May 24, 1982, about the early days of his research at the Ames Research Center, NASA, had appeared in a 2004 review paper. (31)

A bibliography of Ponnamperuma’s published items, compiled by Romero and Navarro-Gonzalez in 1998, consists of 249 items, among which 231 were journal papers, 1 single authored book and 17 co-edited books. (32). This record makes him as one of the prolific scientists Sri Lanka had produced. Based on a scan from the Science Citation Index, the journal papers of Ponnamperuma highlighted in this review were most cited among his publications.

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REFERENCES

• Sullivan W. Cyril Ponnamperuma, scholar of Life’s origins is dead at 71. New York Times, Dec 24, 1994, section 1, p. 10.
• Cyril A Ponnamperuma (obituary). Chemical and Engineering News, Jan 23, 1995, p. 64.
• Sri Kantha S. Cyril Ponnamperuma: Scientist extraordinary. Lanka Guardian, July 15, 1995; 18(5): 19.
• Weintraub P (ed). Seeds of Life – Cyril Ponnamperuma. In: The OMNI Interviews, Ticknor Fields, New York, 1984, pp. 3-19.
• Ponnamperuma C, Lemmon RM, Bennett EL, Calvin M. Deamination of adenine by ionizing radiation. Science, 1961; 134: 113.
• Ponnamperuma C, Lemmon RM, Calvin M. Chemical effect of ionizing radiation on cytosine. Science, 1962; 137: 605-607.
• Ponnamperuma C, Mariner R, Sagan C. Formation of adenosine by ultraviolet irradiation of a solution of adenine and ribose. Nature, 1963; 198: 1100-1200.
• Ponnamperuma C, Sagan C, Mariner R. Synthesis of adenosine triphosphate under possible primitive earth conditions. Nature, 1963; 199: 222-226.
• Ponnamperuma C, Lemmon RM, Mariner R, Calvin M. Formation of adenine by electron irradiation of methane, ammonia and water. Proceedings of National Academy of Science USA, 1963; 49: 737-740.
• Ponnamperuma C, Kirk P, Mariner R, Tyson B. A coincidence technique for paper chromatography. Nature, 1964; 202: 393-394.
• Ponnamperuma C, Woeller F. Differences in the character of C6 to C9 hydrocarbons from gaseous methane in low-frequency electric charges. Nature, 1964; 203: 272-274.
• Ponnamperuma C, Kirk P. Synthesis of deoxyadenosine under simulated primitive earth conditions. Nature, 1964; 203: 400-401.
• Ponnamperuma C, Young R, Munoz EF, McCaw BK. Guanine: Formation during thermal polymerization of aminoacids. Science, 1964; 143: 1449-1450.
• Ponnamperuma C, Peterson E. Peptide synthesis from aminoacids in aqueous solution. Science, 1965; 147: 1572-1574.
• Ponnamperuma C Mack R. Nucleotide synthesis under possible primitive earth conditions. Science, 1965; 148: 1221-1223.
• Ponnamperuma C, Pering K. Possible abiogenic origin of some naturally occurring hydrocarbons. Nature, 1966; 209: 979-982.
• Gabel NW, Ponnamperuma C. Model for the origin of monosaccharides. Nature, 1967; 216: 453-455.
• Rabinowitz J, Chang S, Ponnamperuma C. Phosphorylation by way of inorganic phosphate as a potential prebiotic process. Nature, 1968; 218: 442-443.
• Schwartz A, Ponnamperuma C. Phosphorylation of adenine with linear polyphosphate salts in aqueous solution. Nature, 1968; 218: 443.
• Chang S, Flores J, Ponnamperuma C. Peptide formation mediated by hydrogen cyanide tetramer: a possible prebiotic process. Proceedings of National Academy of Sciences USA, 1969; 64: 1011-1015.
• Kvenvolden K, Lawless J, Pering K, Peterson E, Flores J, Ponnamperuma C, Kaplan I, Moore C. Evidence for extraterrestrial aminoacids and hydrocarbons in the Murchison meteorite. Nature, 1970; 228: 923-926.
• Kvenvolden K, Lawless JG, Ponnamperuma C. Non-protein aminoacids in the Murchison meteorite. Proceedings of National Academy of Sciences USA, 1971; 68: 486-490.
• Ponnamperuma C, Kvenvolden K, Chang S, Johnson R, Pollock G. et al. Search for organic compounds in the lunar dust from the Sea of Tranquility. Science, 1970; 167: 760-762.
• Hodgson GW, Peterson E, Kvenvolden KA, Bunnenberg E, Halpern B, Ponnamperuma C. Search for porphyrins in lunar dust. Science, 1970; 167: 763-765.
• Chang S, Kvenvolden K, Lawless J, Ponnamperuma C, Kaplan IR. Carbon, carbides and methane in an Apollo 12 sample. Science, 1971; 171: 474-477.
• Ponnamperuma C, Shimoyama A, Yamada M, Hobo T, Pal R. Possible surface reactions on Mars: Implications for Viking Biology results. Science, 1977; 197: 455-457.
• Ponnamperuma C. Primordial organic chemistry and the origin of life. Quarterly Review of Biophysics, 1971; 4: 77-106.
• Ponnamperuma C, MacDermott AJ. Cosmic chemistry: the meaning of life. Chemistry in Britain, 1994; 30(6): 487-490.
• Ponnamperuma C, Klein HP. The coming search for life on Mars. Quarterly Review of Biology, 1970; 45: 235-258.
• Ponnamperuma C, Molton P. Life on Jupiter? New Scientist, Dec 6, 1973; 60: 692-693.
• Strick JE. Creating a cosmic discipline: The crystallization and consolidation of exobiology, 1957-1973. Journal of History of Biology, 2004; 37(1): 131-180.
• Romero A, Navarro-Gonzalez R. Cyril Ponnamperuma and the Origin of Life – a bibliography. Origins of Life and Evolution of the Biosphere, 1998; 28: 109-121.

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