Marcos Boris Rotman (December 4, 1924 – July 11, 2021) was a Chilean American immunologistmolecular biologist and professor emeritus of Medical Science at Alpert Medical School of Brown University.[2] He is widely recognized for performing the first single molecule experiments in biology.[3][4][5][6][7] He died in July 2021 at the age of 96.[8]

Marcos Boris Rotman
Boris Rotman, 2011
Born(1924-12-04)December 4, 1924[1]
DiedJuly 11, 2021(2021-07-11) (aged 96)
CitizenshipAmerican
Alma materUniversity of Illinois (PhD, 1952)
Universidad Tecnica Federico Santa Maria (M.S., 1948)
Known forFirst single molecule experiment in biology
Spouse(s)Raquel Yudelevich S. (1933-1971; widowed)
Rosario Guzman-Rotman (married 1993)
ChildrenJessica R. Yates
AwardsState of Rhode Island Governor's Award for Scientific Achievement (1990)
Scientific career
FieldsBiochemistry
Molecular biology
InstitutionsBrown University
Stanford Medical School
Syntex Institute for Molecular Biology, Stanford
Escuela de Medicina, Universidad de Chile
Karolinska Institute
Weizmann Institute of Science – Dept. of Chemical Immunology
Thesis A heritable conversion of phenotype in yeast.  (1952)
Doctoral advisorSalvador Luria and Sol Spiegelman
Other academic advisorsJoshua Lederberg

Education edit

Rotman attended elementary and high school at the Instituto Nacional of Chile. In 1942, he won a scholarship to attend the Universidad Técnica Federico Santa Maria, from where he graduated with a chemical engineering degree in 1948. In 1950, he entered the University of Illinois and in 1952 earned a PhD in biochemistry/microbiology.[9] His mentors at University of Illinois were Salvador E. Luria (Nobel laureate 1969) and Sol Spiegelman (Albert Lasker Award for Basic Medical Research, 1974). After graduation, Rotman was a postdoctoral researcher in the group of Joshua Lederberg (Nobel laureate 1958) at University of Wisconsin-Madison, and later, in the laboratory of Bernard D. Davis at Harvard Medical School.[10]

Research career edit

In 1961, Rotman developed a system capable of measuring the enzymatic activity of individual molecules of beta-galactosidase and used it to conduct the first single-molecule experiment in biology.[4][5][6][7][11]

These early experiments remained obscure for more than 30 years, but they are now recognized as pioneering and highly influential.[4][5][6][7] A review states, "Indeed, this paper is the origin not only of the field of single-molecule enzymology, but also of much subsequent single-molecule research."[4] The significance of single-molecule experiments derives from their capacity to provide fundamental insights that are not attainable by conventional experimentation. For example (a) Enzyme turnover can be measured directly from the number of fluorescent molecules of product produced by an individual enzyme molecule. (b) Studying heat inactivation of an enzyme at the single molecule level uncovered unprecedented mechanisms. Namely, heating causes an all-or-none distribution of enzymatic activity, i. e., the molecular population consists of either fully active or completely inactive enzyme molecules.[11] This experiment rules out an alternative plausible mechanism postulating that partial heat inactivation produces enzyme molecules with partial activity; (c) In contrast, partial inactivation of beta-galactosidase resulting from storing crystalline enzyme under ammonium sulfate at low temperature (3-6 °C) for several years, causes a uniform distribution of partially inactivated enzyme molecules,[12] (d) A point mutation in the lacZ gene alters beta-galactosidase activity producing uniform populations of beta-galactosidase molecules with individual partial activity.[11]

It is noteworthy that the first single-molecule experiment utilized two innovative technologies, droplet-based microfluidics and fluorogenic substrates. The former was developed by J. F. Collins to measure penicillinase content of individual Bacillus licheniformis.[13] The latter, fluorogenic substrates are non-fluorescent compounds yielding fluorescent products upon enzymatic action. Fluorogenic substrates serve to increase the sensitivity of enzyme assays and many are commercially available.

In 1966, Rotman and Papermaster discovered fluorochromasia, a universal cellular phenomenon characterized by the immediate appearance of bright green fluorescence inside viable cells upon exposure to certain membrane permeable fluorogenic substrates such as fluorescein diacetate, fluorescein dibutyrate, and fluorescein dipropionate.[14] The phenomenon is commonly used to measure cellular viability of many different species including animals, embryos, plants, and microorganisms.

In 1968, Rotman and Celada reported existence of a subset of antibodies with the unprecedented ability to restore the activity of mutated molecules of defective beta-galactosidase by conformational change.[15] Subsequently, this exceptional ability of some antibodies has been subject of many studies.[16]

Awards edit

In 1990, Rotman received the State of Rhode Island Governor's Award for Scientific Excellence.[17]

Selected publications edit

References edit

  1. ^ American Men & Women of Science (2008), Vol. 6, pg. 345
  2. ^ "Brown University". Retrieved October 10, 2018.
  3. ^ Lord, Samuel J.; Lee, Hsiao-lu D.; Moerner, W. E. (March 15, 2010). "Single-Molecule Spectroscopy and Imaging of Biomolecules in Living Cells". Analytical Chemistry. 82 (6). American Chemical Society (ACS): 2192–2203. doi:10.1021/ac9024889. ISSN 0003-2700. PMC 2838489. PMID 20163145.
  4. ^ a b c d Knight, Alex E. (2011). "Single Enzyme Studies: A Historical Perspective". Single Molecule Enzymology. Methods in Molecular Biology. Vol. 778. Totowa, NJ: Humana Press. pp. 1–9. doi:10.1007/978-1-61779-261-8_1. ISBN 978-1-61779-260-1. ISSN 1064-3745. PMID 21809196.
  5. ^ a b c Engelkamp, Hans; Hatzakis, Nikos S.; Hofkens, Johan; De Schryver, Frans C.; Nolte, Roeland J. M.; Rowan, Alan E. (2006). "Do enzymes sleep and work?". Chemical Communications (9). Royal Society of Chemistry (RSC): 935–40. doi:10.1039/b516013h. hdl:2066/35945. ISSN 1359-7345. PMID 16491170. S2CID 1460026.
  6. ^ a b c Bard, Allen J. (December 23, 2008). "Toward Single Enzyme Molecule Electrochemistry". ACS Nano. 2 (12). American Chemical Society (ACS): 2437–2440. doi:10.1021/nn800801z. ISSN 1936-0851. PMID 19206276.
  7. ^ a b c Walt, David R. (December 19, 2012). "Optical Methods for Single Molecule Detection and Analysis". Analytical Chemistry. 85 (3). American Chemical Society (ACS): 1258–1263. doi:10.1021/ac3027178. ISSN 0003-2700. PMC 3565068. PMID 23215010.
  8. ^ Homenaje a Marcos Boris Rotman (Q.E.P.D)
  9. ^ Mathys, J.M.; Smithsonian Archives; Alfred P. Sloan Foundation (1992). Guide to the collections of the Smithsonian Videohistory Program: sponsored by the Alfred P. Sloan Foundation. Smithsonian Institution Archives. p. 8. Retrieved June 23, 2019. Marcos Boris Rotman received his MS in chemical engineering from the University F. Santa Maria in Chile in 1948, and his Ph.D. in microbiology, organic chemistry, and biochemistry from the University of Illinois in 1952. After completing his ...
  10. ^ "The History of the Cell Sorter Interviews · SOVA". SOVA. Retrieved June 22, 2019.
  11. ^ a b c Rotman, B. (December 1, 1961). "Measurement of activity of single molecules of β-D-galactosidase". Proceedings of the National Academy of Sciences. 47 (12): 1981–1991. Bibcode:1961PNAS...47.1981R. doi:10.1073/pnas.47.12.1981. ISSN 0027-8424. PMC 223251. PMID 14038788.
  12. ^ The Lactose Operon. 1970. ISBN 978-0-317-11809-4.
  13. ^ Collins, J. F. (1962). "Estimation of penicillinase in single bacterial cells". Biochem. J. 82: 28 P.
  14. ^ Pilet, P.E. (2012). The Physiological Properties of Plant Protoplasts. Proceedings in Life Sciences. Springer Berlin Heidelberg. p. 29. ISBN 978-3-642-70144-3. Retrieved June 22, 2019. The other fluorochrome, fluorescein diacetate, first shown in 1966 (Rotman and Papermaster 1966) to induce fluorescence in animal cells was subsequently adapted to plant cells (Heslop-Harrison and Heslop-Harrison 1970, Widholm 1972) ...
  15. ^ Rotman, M. B.; Celada, F. (June 1, 1968). "Antibody-mediated activation of a defective beta-D-galactosidase extracted from an Escherichia coli mutant". Proceedings of the National Academy of Sciences. 60 (2): 660–667. Bibcode:1968PNAS...60..660R. doi:10.1073/pnas.60.2.660. ISSN 0027-8424. PMC 225097. PMID 4882747.
  16. ^ Celada, F.; Schumaker, V.N.; Sercarz, E.E. (2012). Protein Conformation as an Immunological Signal. Springer US. p. 240. ISBN 978-1-4613-3778-2. Retrieved June 22, 2019.
  17. ^ "Rotman, Boris". Researchers @ Brown. February 14, 2019. Archived from the original on February 14, 2019. Retrieved June 22, 2019.