Shiladitya DasSarma (born 1957) is a molecular biologist well-known for his contributions to the biology of salt-loving halophilic microorganisms. He obtained a BS degree in Chemistry from Indiana University and a PhD degree in Biochemistry from the Massachusetts Institute of Technology. He conducted postdoctoral research at Massachusetts General Hospital, Harvard Medical School, and Pasteur Institute, Paris.
DasSarma 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 an active researcher and teacher (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 and extremophile research.
In early work (1980's), he discovered mobile genetic elements in Haloarchaea, while a graduate student with H. Gobind Khorana (Nobel Laureate) and Uttam L. RajBhandary. He also showed that transcriptional promoters in Archaea were different from those in other Bacteria, which contributed to the acceptance of the three Domain view of evolution proposed by Carl Woese.
In the 1990's, he organized and led the team that deciphered the first genome sequence and genetic code for a salt-loving microbe, Halobacterium sp. NRC-1. This work showed that certain proteins are highly acidic, providing an understanding of how proteins function in high salinity and low water activity conditions. The genome sequence helped to further establish the validity of the Archaea through the finding of similarities to higher organisms and differences from Bacteria. The work also suggested that certain genes are acquired through horizontal gene transfers, such as the genes for aerobic respiration. Later in the 2000's, post-genomic research in his laboratory established signature proteins in halophilic Archaea, and the function of many genes and genetic elements, including multiple replication origins, general transcription factors, and DNA repair systems.
DasSarma’s recent research (2010's) on an Antarctic halophilic microorganism, Halorubrum lacusprofundi, resulted in further refinement in understanding of protein function in high salinity and cold conditions. Such studies may explain how life could adapt to new environments, including extraterrestrial environments.
DasSarma proposed that retinal pigments originally discovered in halophilic Archaea may have predated chlorophyll pigments in the early earth, named the "Purple Earth" hypothesis.
One of the interesting features of Halobacterium sp. NRC-1 is the presence of buoyant gas vesicle nanoparticles (GVNPs). DasSarma’s laboratory has been instrumental in their study, and developed an expression system to bioengineer GVNPs. These may represent a valuable platform for antigen delivery, vaccine development, and other biomedical and environmental applications