Shiladitya DasSarma

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Shiladitya DasSarma
Shiladitya DasSarma.jpg
Born (1957-11-11) November 11, 1957 (age 66)
Kolkata, India
NationalityAmerican (Naturalized)
Education Indiana University (BS)
Massachusetts Institute of Technology (PhD)
OccupationProfessor
Employer University of Maryland Baltimore
Known for Haloarchaea, Climate Action
Awards Margaret MacVicar Award

Shiladitya DasSarma (born November 11, 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.

Contents

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]

Related Research Articles

A halophile is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species.

<i>Halobacterium</i> Genus of archaea

Halobacterium is a genus in the family Halobacteriaceae.

<span class="mw-page-title-main">Halobacteriales</span> Order of archaea

Halobacteriales are an order of the Halobacteria, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments where large amounts of salt, moisture, and organic material are available. Large blooms appear reddish, from the pigment bacteriorhodopsin. This pigment is used to absorb light, which provides energy to create ATP. Halobacteria also possess a second pigment, halorhodopsin, which pumps in chloride ions in response to photons, creating a voltage gradient and assisting in the production of energy from light. The process is unrelated to other forms of photosynthesis involving electron transport; however, and halobacteria are incapable of fixing carbon from carbon dioxide.

<span class="mw-page-title-main">Haloarchaea</span> Class of salt-tolerant archaea

Haloarchaea are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. Halobacteria are now recognized as archaea rather than bacteria and are one of the largest groups. The name 'halobacteria' was assigned to this group of organisms before the existence of the domain Archaea was realized, and while valid according to taxonomic rules, should be updated. Halophilic archaea are generally referred to as haloarchaea to distinguish them from halophilic bacteria.

Microbial genetics is a subject area within microbiology and genetic engineering. Microbial genetics studies microorganisms for different purposes. The microorganisms that are observed are bacteria, and archaea. Some fungi and protozoa are also subjects used to study in this field. The studies of microorganisms involve studies of genotype and expression system. Genotypes are the inherited compositions of an organism. Genetic Engineering is a field of work and study within microbial genetics. The usage of recombinant DNA technology is a process of this work. The process involves creating recombinant DNA molecules through manipulating a DNA sequence. That DNA created is then in contact with a host organism. Cloning is also an example of genetic engineering.

Bactericidal permeability-increasing protein (BPI) is a 456-residue (~50kDa) protein that is part of the innate immune system, coded for in the human by the BPI gene. It belongs to the family of lipid-binding serum glycoproteins.

<i>Halobacterium salinarum</i> Species of archaeon

Halobacterium salinarum, formerly known as Halobacterium cutirubrum or Halobacterium halobium, is an extremely halophilic marine obligate aerobic archaeon. Despite its name, this is not a bacterium, but a member of the domain Archaea. It is found in salted fish, hides, hypersaline lakes, and salterns. As these salterns reach the minimum salinity limits for extreme halophiles, their waters become purple or reddish color due to the high densities of halophilic Archaea. H. salinarum has also been found in high-salt food such as salt pork, marine fish, and sausages. The ability of H. salinarum to survive at such high salt concentrations has led to its classification as an extremophile.

Halorubrum is a genus in the family Halorubraceae. Halorubrum species areusually halophilic and can be found in waters with high salt concentration such as the Dead Sea or Lake Zabuye.

In taxonomy, Natrialba is a genus of the Natrialbaceae. The genus consists of many diverse species that can survive extreme environmental niches, especially they are capable to live in the waters saturated or nearly saturated with salt (halophiles). They have certain adaptations to live within their salty environments. For example, their cellular machinery is adapted to high salt concentrations by having charged amino acids on their surfaces, allowing the cell to keep its water molecules around these components. The osmotic pressure and these amino acids help to control the amount of salt within the cell.

Halocins are bacteriocins produced by halophilic Archaea and a type of archaeocin.

GvpA is a gas vesicle structural protein found in different phyla of bacteria and archaea for example in Halobacterium salinarum or Haloferax mediterranei. Gas vesicles are small, hollow, gas filled protein structures found in several cyanobacterial and archaebacterial microorganisms. They allow the positioning of the bacteria at a favourable depth for growth.

<i>Haloferax volcanii</i> Species of Halobacteria

Haloferax volcanii is a species of organism in the genus Haloferax in the Archaea.

<i>Haloquadratum walsbyi</i> Species of archaeon

Haloquadratum walsbyi is of the genus Haloquadratum, within the archaea domain known for its square halophilic nature. First discovered in a brine pool in the Sinai peninsula of Egypt, H. walsbyi is noted for its flat, square-shaped cells, and its unusual ability to survive in aqueous environments with high concentrations of sodium chloride and magnesium chloride. The species' genus name Haloquadratum translates from Greek and Latin as "salt square". This archaean is also commonly referred to as "Walsby's Square Bacterium" because of its identifying square shape which makes it unique. In accordance with its name, Haloquadratum walsbyi are most abundantly observed in salty environments.

<i>Methanohalophilus mahii</i> Species of archaeon

Methanohalophilus mahii is an obligately anaerobic, methylotrophic, methanogenic cocci-shaped archaeon of the genus Methanohalophilus that can be found in high salinity aquatic environments. The name Methanohalophilus is said to be derived from methanum meaning "methane" in Latin; halo meaning "salt" in Greek; and mahii meaning "of Mah" in Latin, after R.A. Mah, who did substantial amounts of research on aerobic and methanogenic microbes. The proper word in ancient Greek for "salt" is however hals (ἅλς). The specific strain type was designated SLP and is currently the only identified strain of this species.

Halobacterium noricense is a halophilic, rod-shaped microorganism that thrives in environments with salt levels near saturation. Despite the implication of the name, Halobacterium is actually a genus of archaea, not bacteria. H. noricense can be isolated from environments with high salinity such as the Dead Sea and the Great Salt Lake in Utah. Members of the Halobacterium genus are excellent model organisms for DNA replication and transcription due to the stability of their proteins and polymerases when exposed to high temperatures. To be classified in the genus Halobacterium, a microorganism must exhibit a membrane composition consisting of ether-linked phosphoglycerides and glycolipids.

<span class="mw-page-title-main">Gas vesicle</span>

Gas vesicles, also known as gas vacuoles, are nanocompartments in certain prokaryotic organisms, which help in buoyancy. Gas vesicles are composed entirely of protein; no lipids or carbohydrates have been detected.

Haloterrigena turkmenica is an aerobic chemo organotrophic archeon originally found in Turkish salt lakes.

Haloarcula marismortui is a halophilic archaeon isolated from the Dead Sea

<i>Haloferax mediterranei</i> Species of bacterium

Haloferax mediterranei is a species of archaea in the family Haloferacaceae.

<i>Halorubrum lacusprofundi</i> Species of archaeon

Halorubrum lacusprofundi is a rod-shaped, halophilic Archaeon in the family of Halorubraceae. It was first isolated from Deep Lake in Antarctica in the 1980s.

References

  1. ↑ "Extreme Halophiles Are Models for Astrobiology" (PDF). Microbe. 2006.
  2. 1 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. Bibcode:1982PNAS...79.7268S. 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. Bibcode:1983PNAS...80.2201D. 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. Bibcode:1984PNAS...81..125D. 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. Bibcode:2013PLoSO...858587D. 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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