Shiladitya DasSarma

Shiladitya DasSarma (born 1957) is a molecular biologist well-known for contributions to the biology of halophilic and extremophilic microorganisms.[1][2] He is a Professor in the University of Maryland Baltimore. He earned a PhD degree in Biochemistry from the Massachusetts Institute of Technology and a BS degree in Chemistry from Indiana University Bloomington. Prior to taking a faculty position, he conducted research at the Massachusetts General Hospital, Harvard Medical School, and Pasteur Institute, Paris.

Shiladitya DasSarma
Born1957
Kolkata, India
NationalityAmerican (Naturalized)
Alma materIndiana University (BS)
Massachusetts Institute of Technology (PhD)
Known forLife in Extreme Environments, Halophiles, Archaea, Astrobiology

DasSarma has served on the faculty of the University of Massachusetts Amherst (1986-2001), University of Maryland Biotechnology Institute (2001-2010), and University of Maryland School of Medicine, Institute of Marine and Environmental Technology (2010–present). He is a researcher and teacher of molecular genetics, genomics, and bioinformatics and mentor of undergraduate, graduate and postdoctoral students, and junior faculty. He is widely known to have been instrumental in the foundation of the fields of halophile[3] and extremophile research.

Research

Halophiles

In early work (1980's), he discovered mobile genetic elements in halophilic Archaea,[4][5] while a graduate student with H. Gobind Khorana (Nobel laureate) and Uttam L. RajBhandary at MIT. He also showed that transcriptional promoters in Archaea[6] were different from those in common Bacteria, which contributed to the acceptance of the three Domain view of evolution proposed by Carl Woese.

In the 1990s, he organized and led the team that deciphered the first genome sequence and genetic code for a halophilic microbe, Halobacterium sp. NRC-1.[7][8][9] This work showed that its proteins are highly acidic, providing an understanding of how proteins may function in high salinity and low water activity conditions.[10][11][12] The genome sequence helped to further establish the validity of the Archaea[13] through the finding of similarities to higher eukaryotic organisms and differences from Bacteria.

Later in the 2000s, his work also suggested that certain genes are acquired through horizontal gene transfers, such as the genes for aerobic respiration. Post-genomic research in his laboratory established the core and signature proteins in halophilic Archaea,[14] and the function of many genes and genetic elements, including multiple replication origins,[15] general transcription factors,[16] and DNA repair systems.[17][18]

Astrobiology

DasSarma's recent research (2010's) on an Antarctic halophilic microorganism, Halorubrum lacusprofundi, resulted in further refinement in understanding of protein function in a combination of high salinity and cold conditions.[19] Such studies may explain how life could adapt to new environments, including extraterrestrial environments.[20]

DasSarma proposed that retinal pigments originally discovered in halophilic Archaea may have predated chlorophyll pigments in the early earth, named the "Purple Earth" hypothesis.[2][21] This proposal provides a potential new biosignature for remote detection of life.

Biotechnology

DasSarma's laboratory has been instrumental in the study of buoyant gas vesicle nanoparticles (GVNPs) in Halobacterium sp. NRC-1, and developed an expression system to bioengineer GVNPs for biotechnology applications.[22] These nanoparticles may represent a valuable platform for antigen delivery, vaccine development, and other biomedical and environmental applications[23][24]

References
  1. "Extreme Halophiles Are Models for Astrobiology" (PDF). Microbe. 2006.
  2. "Extreme Microbes » American Scientist". www.americanscientist.org. Retrieved 2016-07-11.
  3. DasSarma, Shiladitya; DasSarma, Priya (2001-01-01). Halophiles. John Wiley & Sons, Ltd. doi:10.1002/9780470015902.a0000394.pub3. ISBN 9780470015902.
  4. Simsek, M.; DasSarma, S.; RajBhandary, U. L.; Khorana, H. G. (1982-12-01). "A transposable element from Halobacterium halobium which inactivates the bacteriorhodopsin gene". Proceedings of the National Academy of Sciences. 79 (23): 7268–7272. doi:10.1073/pnas.79.23.7268. ISSN 0027-8424. PMC 347320. PMID 6296826.
  5. DasSarma, S.; RajBhandary, U. L.; Khorana, H. G. (1983-04-01). "High-frequency spontaneous mutation in the bacterio-opsin gene in Halobacterium halobium is mediated by transposable elements". Proceedings of the National Academy of Sciences. 80 (8): 2201–2205. doi:10.1073/pnas.80.8.2201. ISSN 0027-8424. PMC 393786. PMID 6300900.
  6. DasSarma, Shiladitya; RajBhandary, Uttam L.; Khorana, H. Gobind (1984-01-01). "Bacterio-opsin mRNA in wild-type and bacterio-opsin-deficient Halobacterium halobium strains". Proceedings of the National Academy of Sciences. 81 (1): 125–129. doi:10.1073/pnas.81.1.125. ISSN 0027-8424. PMC 344623. PMID 16593404.
  7. Ng, WaiLap V.; Ciufo, Stacy A.; Smith, Todd M.; Bumgarner, Roger E.; Baskin, Dale; Faust, Janet; Hall, Barbara; Loretz, Carol; Seto, Jason (1998-11-01). "Snapshot of a Large Dynamic Replicon in a Halophilic Archaeon: Megaplasmid or Minichromosome?". Genome Research. 8 (11): 1131–1141. doi:10.1101/gr.8.11.1131. ISSN 1088-9051. PMID 9847077.
  8. Ng, Wailap Victor; Kennedy, Sean P.; Mahairas, Gregory G.; Berquist, Brian; Pan, Min; Shukla, Hem Dutt; Lasky, Stephen R.; Baliga, Nitin S.; Thorsson, Vesteinn (2000-10-24). "Genome sequence of Halobacterium species NRC-1". Proceedings of the National Academy of Sciences. 97 (22): 12176–12181. doi:10.1073/pnas.190337797. ISSN 0027-8424. PMC 17314. PMID 11016950.
  9. "NSF - OLPA - PR 00-69: International Research Group Sequences Genome of Ubiquitous Microbe". www.nsf.gov. Retrieved 2016-07-11.
  10. Kennedy, Sean P.; Ng, Wailap Victor; Salzberg, Steven L.; Hood, Leroy; DasSarma, Shiladitya (2001-10-01). "Understanding the Adaptation of Halobacterium Species NRC-1 to Its Extreme Environment through Computational Analysis of Its Genome Sequence". Genome Research. 11 (10): 1641–1650. doi:10.1101/gr.190201. ISSN 1088-9051. PMC 311145. PMID 11591641.
  11. Karan, Ram; Capes, Melinda D.; DasSarma, Shiladitya (2012-01-01). "Function and biotechnology of extremophilic enzymes in low water activity". Aquatic Biosystems. 8 (1): 4. doi:10.1186/2046-9063-8-4. ISSN 2046-9063. PMC 3310334. PMID 22480329.
  12. DasSarma, Shiladitya; DasSarma, Priya (2015-06-01). "Halophiles and their enzymes: negativity put to good use". Current Opinion in Microbiology. Environmental microbiology • Extremophiles. 25: 120–126. doi:10.1016/j.mib.2015.05.009. PMC 4729366. PMID 26066288.
  13. DasSarma, S., J.A. Coker, and P. DasSarma. 2010. Archaea - Overview. In Encyclopedia of Microbiology, 3rd edition, Academic Press, M. Schaechter (ed.), p. 118-139.
  14. Capes, Melinda D.; DasSarma, Priya; DasSarma, Shiladitya (2012-01-01). "The core and unique proteins of haloarchaea". BMC Genomics. 13: 39. doi:10.1186/1471-2164-13-39. ISSN 1471-2164. PMC 3287961. PMID 22272718.
  15. Berquist, Brian R.; DasSarma, Shiladitya (2003-10-15). "An Archaeal Chromosomal Autonomously Replicating Sequence Element from an Extreme Halophile, Halobacterium sp. Strain NRC-1". Journal of Bacteriology. 185 (20): 5959–5966. doi:10.1128/JB.185.20.5959-5966.2003. ISSN 0021-9193. PMC 225043. PMID 14526006.
  16. Coker, James A.; DasSarma, Shiladitya (2007-01-01). "Genetic and transcriptomic analysis of transcription factor genes in the model halophilic Archaeon: coordinate action of TbpD and TfbA". BMC Genetics. 8: 61. doi:10.1186/1471-2156-8-61. ISSN 1471-2156. PMC 2121645. PMID 17892563.
  17. Karan, R; DasSarma, P; Balcer-Kubiczek, E; Weng, RR; Liao, CC; Goodlett, DR; Ng, WV; Dassarma, S (2014). "Bioengineering radioresistance by overproduction of RPA, a mammalian-type single-stranded DNA-binding protein, in a halophilic archaeon". Applied Microbiology and Biotechnology. 98 (4): 1737–1747. doi:10.1007/s00253-013-5368-x. PMC 4096848. PMID 24292079.
  18. Weiss, Rick (2007-09-25). "'Superbugs' Could Benefit Humans". The Washington Post. ISSN 0190-8286. Retrieved 2016-07-11.
  19. DasSarma, Shiladitya; Capes, Melinda D.; Karan, Ram; DasSarma, Priya (2013-03-11). "Amino Acid Substitutions in Cold-Adapted Proteins from Halorubrum lacusprofundi , an Extremely Halophilic Microbe from Antarctica". PLOS ONE. 8 (3): e58587. doi:10.1371/journal.pone.0058587. ISSN 1932-6203. PMC 3594186. PMID 23536799.
  20. "BioTechniques - Antarctic Microbe's Survival Tricks Revealed". www.biotechniques.com. Retrieved 2016-07-11.
  21. "Extremophiles and Extraterrestrial Life".
  22. DasSarma, Shiladitya; Karan, Ram; DasSarma, Priya; Barnes, Susan; Ekulona, Folasade; Smith, Barbara (2013-01-01). "An improved genetic system for bioengineering buoyant gas vesicle nanoparticles from Haloarchaea". BMC Biotechnology. 13: 112. doi:10.1186/1472-6750-13-112. ISSN 1472-6750. PMC 3878110. PMID 24359319.
  23. DasSarma, P.; Negi, V. D.; Balakrishnan, A.; Kim, J. -M.; Karan, R.; Chakravortty, D.; DasSarma, S. (2015-01-01). "Procedia of the 8th Vaccine & ISV Congress, Philadelphia, USA, 2015Haloarchaeal Gas Vesicle Nanoparticles Displaying Salmonella Antigens as a Novel Approach to Vaccine Development". Procedia in Vaccinology. 9: 16–23. doi:10.1016/j.provac.2015.05.003. PMC 4758358. PMID 26900411.
  24. DasSarma, Shiladitya; DasSarma, Priya (2015-09-07). "Gas Vesicle Nanoparticles for Antigen Display". Vaccines. 3 (3): 686–702. doi:10.3390/vaccines3030686. PMC 4586473. PMID 26350601.
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