The DasSarma Lab Group

8/08

Left to right:

Priya DasSarma, Mindy Capes, Jim Coker, Rachael Gessler, Shil DasSarma

(Anjali and Satyajit, honorary members in foreground)

SUMMARY OF RESEARCH INTERESTS

The research interests of the lab group include the genomics, biotechnology, and molecular biology of halophilic archaea (haloarchaea). Haloarchaea grow optimally at 4.3 M NaCl and contain essentially saturated concentration of salts internally (1). Haloarchaea are excellent model organisms because they are easy to culture in the lab, are genetically tractable, and exhibit a variety of interesting and valuable characteristics (2). Our lab is taking a whole genome approach to the study of halophiles using the model archaeon, Halobacterium sp. strain NRC-1, which contains a completely sequenced 2,571,010 bp genome (3). Among the 2,630 genes in Halobacterium, we have been studying the gas vesicle gene cluster for many years. This gene cluster was shown to be necessary and sufficient for gas vesicle production and its biogenesis is currently being analyzed in detail (4,6). The vesicles are also bioengineerable, and their use in design of vaccines and for other applications is of current interest (6). Another area of long-term interest has been the bop gene coding for the purple membrane protein, bacterio-opsin. The bop gene promoter, which is regulated by oxygen and light, responds to environmental changes, probably via the action of alternate TATA-binding protein and TFB proteins in this organism (7). The possibility of alternate DNA structures, such as Z-DNA, in the genome stabilized by high salinity is fascinating (8). Future studies of Halobacterium systems biology and functional genomics offer exciting opportunities through the use of DNA microarrays and systematic knockouts of genes (9,10). Such approaches will help us to better understand the mechanisms of adaptation of haloarchaea to hypersaline environments and clarify their evolutionary position among organisms on the planet.

For current openings in the lab, please contact Dr. S. DasSarma at dassarma@umbi.umd.edu.

References

1. DasSarma, S. and P. Arora. 2002. Halophiles, Encyclopedia of Life Sciences, vol 8:458-466. London:  Nature Publishing Group.

 

2. DasSarma, S., et al. (eds). 1995. Archaea: A Laboratory Manual - Halophiles, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.

3. Ng WV, Kennedy SP, Mahairas GG, Berquist B, Pan M, Shukla HD, Lasky SR, Baliga NS, Thorsson V, Sbrogna J, Swartzell S, Weir D, Hall J, Dahl TA, Welti R, Goo YA, Leithauser B, Keller K, Cruz R, Danson MJ, Hough DW, Maddocks DG, Jablonski PE, Krebs MP, Angevine CM, Dale H, Isenbarger TA, Peck RF, Pohlschroder M, Spudich JL, Jung KH, Alam M, Freitas T, Hou S, Daniels CJ, Dennis PP, Omer AD, Ebhardt H, Lowe TM, Liang P, Riley M, Hood L, DasSarma S. 2000. Genome sequence of Halobacterium species NRC-1. Proc. Natl. Acad. Sci. USA 97:1217612181.

4. DasSarma, S. and P. Arora. 1997. Genetic analysis of the gas vesicle gene cluster in haloarchaea. FEMS Microbiol. Lett. 153:1-10.

5. Shukla, H.D. and S. DasSarma. 2004. Complexity of Gas Vesicle Biogenesis in Halobacterium sp. Strain NRC-1: Identification of Five New Proteins. J. Bacteriol. 186:3182-3186.

 

6. Stuart, E.S., F. Morshed, M. Sremac, and S. DasSarma. 2004. Cassette-based presentation of SIV epitopes with recombinant gas vesicles from halophilic archaea. J Biotechnol. 114:225-237.


7. Baliga, N. and S. DasSarma. 1999. Saturation mutagenesis of the TATA-box and upstream activator sequence in the haloarchaeal bop gene promoter. J. Bacteriol. 181:2513-2518.

8. Kim, J.-M., and S. DasSarma. 1996. Isolation and chromosomal distribution of natural Z-DNA-forming sequences in Halobacterium halobium. J. Biol. Chem. 271:19724-19731.

9. Wang, G., S.K. Kennedy, S. Fasiludeen C., Rensing, and S. DasSarma. 2004. Arsenic Resistance in Halobacterium sp. NRC-1 Examined Using an Improved Gene Knockout System. J. Bacteriol. 186:3187-3194.

 

10. Muller, J.A. and S. DasSarma. 2004. Functional genomic analysis of anaerobic respiration of the archaeon Halobacterium sp. NRC-1: dimethyl sulfoxide (DMSO) and trimethylamine N-oxide (TMAO) as terminal electron acceptors, J. Bacteriol. 187:1659-1667.