Sandra Pizzarello (1933-2021)

It is with great sadness that we announce that Sandra Pizzarello passed away on October 24, 2021.

She greatly enhanced the research field of molecular, isotopic, and chiral analysis of organic compounds in carbonaceous chondrite meteorites since the 1970s. During her active research career, she produced an impressive number of achievements in her studies on the origin and chemical evolution of organic compounds in the early Solar System and the origin of homochirality in living systems.

Sandra was born in Venice, Italy, in 1933. She obtained a doctoral degree in Biological Sciences at Universitá degli Studi di Padova, Italy, in 1955. She was a research associate with Farmitalia Research Laboratories, Neuropharmacology Department, Milan, Italy from 1957-1960. She started her research at Department of Chemistry and Biochemistry, Arizona State University (ASU) in 1977. She was a research professor and an emeritus professor at ASU until she passed away.

Sandra was a pioneering scientist who either identified or greatly expanded our knowledge of a suite of soluble compounds in carbonaceous chondrites such as amino acids, monocarboxylic acids, dicarboxylic acids, hydroxyl acids, hydroxydicarboxylic acids, aliphatic hydrocarbons, ammonia, amines, polar hydrocarbons as well as insoluble organic matter (IOM), in collaboration with the late Prof. John R. Cronin. Sandra concentrated her efforts over 30 years with Cronin on the development of the analytical techniques for these compounds, in particular, a diverse suite of over 80 amino acids, which is clearly different from the distributions of terrestrial amino acids. They carried out the first isotopic analysis of amino acids in meteorites and revealed enrichments in D, ¹³C, and ¹⁵N. These results provided the first evidence suggesting a direct relationship between meteoritic organic compounds and interstellar chemistry. Later, Sandra worked on the compound-specific C, H and N isotopic analyses of soluble organic compounds in meteorites. Her results demonstrated the diverse synthetic pathways of these compounds in the early Solar System.

One of the highly laudable achievements in Sandra’s works in collaboration with Cronin was their discovery of L-enantiomeric excesses (ee) in a suite of rare (non-biological) extraterrestrial amino acids from carbonaceous chondrites in 1997. Observing ee in non-biological compounds was definitive evidence that ee were present in the early Solar System. The origin of the amino acid homochirality of life has been one of the most significant, unsolved questions in natural science, and their pioneering discovery established a strong position in the search for the origin of amino acid homochirality of life in the universe. Moreover, she experimentally showed that ee are catalytically transferred from amino acids when sugars are synthesized from the formose reaction. The result suggested that meteoritic amino acids could have provided the symmetry breaking necessary for the evolution of RNA by acting as catalysts of asymmetric syntheses leading to D-sugars. Her extensive works demonstrated the possible universality of molecular asymmetry in the universe, suggesting abiotic origins of biomolecular homochirality.

Her most highly cited papers are:

1. Cronin, J.R. and Pizzarello, S. (1997) Enantiomeric excesses in meteoritic amino acids, Science 275, 951-955.
2. Pizzarello, S. and Weber, A.L. (2004) Prebiotic Amino Acids as Asymmetric Catalysts, Science 303, 1151.
3. Pizzarello, S. and Cronin, J.R. (2000) Non-racemic amino acids in the Murray and Murchison meteorites, Geochimica et Cosmochimica Acta 64, 329-338.
4. Pizzarello S., Huang Y., Becker L., Poreda R.J., Nieman R.A., Cooper G. and Williams M. (2001) The organic content of the Tagish Lake meteorite, Science 293, 2236-2239.

Sandra’s significant contributions to Meteoritics, Astronomy, Astrobiology and Origins of Life have influenced the next generation of scientists in these research fields. She was an effective mentor for younger scientists and a role model for women in science. She served as president of the International Society for the Study of the Origin of Life (ISSOL) – the international Astrobiology society from 2014-2017. She is survived by her husband, Tony, and three children and their families.

Hikaru Yabuta, Hiroshima University, Japan

George Cooper, NASA Ames Research Center, USA

Lynda Williams, Arizona State University, Tempe, USA

Kenso Soai, Tokyo University of Science, Japan

Maitrayee Bose, Arizona State University, Tempe, USA