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DasSarma Lab Group

Lab Group 2013
Left to right: Kyle King, Wolf Pecher, Ram Karan, Shil DasSarma, Priya DasSarma, Sade Ekulona,
Stefan Grotzinger, Susan Barnes (not pictured: Rennie Watson) 

SUMMARY OF RESEARCH INTERESTS

The DasSarma laboratory was established in 1986, soon after the discovery of the Archaea. Since then, we have been studying these novel microbes and their mechanisms of adaptation to challenging habitats, including extreme environments and the human microbiome. We use a combination of genetics, genomics, bioinformatics, transcriptomics, and other approaches to address problems of fundamental importance. Our favorite model organism is Halobacterium sp. NRC-1, a salt-loving, radiation-resistant, and desiccation-tolerant archaeon that is easy to culture in the lab and genetically tractable. We led the sequencing project on Halobacterium (with an international consortium of 12 laboratories), which was published in the October 2000 issue of the Proceedings of the National Academy of Sciences USA. The NRC-1 genome consists of a 2 Mbp circular chromosome and two large plasmids, pNRC100 (191 kbp) and pNRC200 (365 kbp). We have since studied many of the ca. 2,500 genes in the genome and pursued translational research through genetic engineering and biotechnology. For example, the gas vesicle gene cluster of Halobacterium, which has been of long term interest, is bioengineerable, and is being used for antigen delivery and vaccine development. Our studies of microaerobically induced genes led to the discovery of novel regulators, such as the bacterio-opsin activator (Bat) and DMSO reductase regulator (DmsR). Gene regulation studies in our lab have also led to the discovery that expanded families of eukaryotic-type transcription factors (TBP and TFB) coordinate promoter selection and expression of different classes of genes under different growth conditions. Another interest of the lab concerns DNA replication and repair in Halobacterium, which employs both eukaryotic-type proteins (origin binding and single-stranded DNA binding, Orc and RPA) and bacterial-type proteins (nucleotide excision repair, UvrABC). These and other current studies in our laboratory are helping to better understand the strategies for microbial survival and adaptation to develop applications in medicine and the environment.


Recent Publications

Berquist, B.R., P. DasSarma, and S. DasSarma. 2007. Essential and non-essential DNA replication genes in the model haloarchaeon, Halobacterium sp. NRC-1. BMC Genetics 8:31.

Giaquinto, L., P.M. Curmi, K.S. Siddiqui, A. Poljak, E. DeLong, S. DasSarma, and R. Cavicchioli. 2007. Structure and function of cold shock proteins in archaea. J Bacteriol. 189:5738-48.

Coker, J.A., P. DasSarma, J. Kumar, J.A. Müller, and S. DasSarma. 2007. Transcriptional profiling of the model Archaeon Halobacterium sp. NRC-1: responses to changes in salinity and temperature. Saline Systems 3:6.

DeVeaux, L.C., Müller, J.A., Smith, J., Petrisko, J., Wells, D.P., and S. DasSarma. 2007. Extremely radiation-resistant mutants of a halophilic archaeon with increased single-stranded DNA binding protein (RPA) gene expression. Radiation Res. 168:507-514.

Coker, J.A. and S. DasSarma. 2007. Genetic and transcriptomic analysis of transcription factor genes in the model halophilic Archaeon: Coordinate action of TbpD and TfbA. BMC Genetics 8:61.

Lu, Q., J. Han, L. Zhou, J.A. Coker, P. DasSarma, S. DasSarma, and H. Xiang. 2008. General Transcription Factor Directed Heat Shock Response in Extremely Halophilic Archaea: a New Paradigm for Archaeal Gene Regulation. Nucleic Acids Res. 36:3031-3042.

Ng, W.V., B.R. Berquist, J.A. Coker, M.C. Capes, P. DasSarma and S. DasSarma. 2008. Genome sequences of Halobacterium species. Genomics 91:548-552.

DasSarma, P. and S. DasSarma. 2008. On the origin of prokaryotic "species": the taxonomy of halophilic Archaea. Saline Systems 4:5.

Boubriak, I. W.L. Ng, P. DasSarma, S. DasSarma, D.J. Crowley, and S.J. McCready. 2008. Transcriptional responses to biologically relevant doses of UV-B radiation in the model archaeon, Halobacterium sp. NRC-1. Saline Systems 4:13.

DasSarma, S., M. Capes, and P. DasSarma. 2008. Haloarchaeal megaplasmids. megaplasmids. In Microbial Megaplasmids, E. Schwartz (ed.), Springer-Verlag, Berlin, pp. 3-30.

Sparks, W.B., J.H. Hough, L. Kolokolova, T. Germer, F. Chen, S. DasSarma , P. DasSarma, F. Robb, N. Manset, I. N. Reid, F. D. Macchetto, and W. Martin 2009. Journal of Quantitative Spectroscopy and Radiative Transfer 110:1771-1779.

Coker, J.A., P. DasSarma, M. Capes, T. Wallace, K. McGarrity, R. Gessler, J. Liu, H. Xiang, R. Tatusov, B.R. Berquist, and S. DasSarma. 2009. Multiple replication origins of Halobacterium sp. NRC-1: Properties of the conserved orc7-dependent oriC1. J. Bacteriol. 191:5253-5261.

Sparks, W.B., J. Hough, T.A. Germer, F. Chen, S. DasSarma, P. DasSarma, F.T. Robb, N. Manset, L. Kolokolova, N. Reid, F.D. Macchetto, and W. Martin. 2009. Detection of Circular Polarization in Light Scattered from Photosynthetic Microbes. Proc. Natl. Acad. Sci. USA 106:7816-7821.

Capes MD, Coker JA, Gessler R, Grinblat-Huse V, DasSarma SL, Jacob CG, Kim JM, DasSarma P, DasSarma S. 2011. The information transfer system of halophilic archaea. Plasmid 65:77-101.

Karan R, Capes MD, DasSarma S. 2012. Function and biotechnology of extremophilic enzymes in low water activity. Aquatic Biosystems 8:4.

Capes MD, DasSarma P, DasSarma S. 2012. The core and unique proteins of haloarchaea. BMC Genomics 13:39.


For current openings in the lab, please contact Prof. S. DasSarma at sdassarma@som.umaryland.edu.