Microbial interactions are likely as old as life itself and will continue to play an integral role in shaping microbial diversity. Can we use a combination of culturing and molecular techniques (e.g. next-gen sequencing) to understand how these interactions evolved, how important are they today, and how will they respond to climate change?
Email: shadyam at u.washington.edu
Ph.D. in Bioinorganic Chemistry, University of California, San Diego/San Diego State University (2010)
M.A. in Inorganic Chemistry, San Diego State University (2005)
B.Sc. in Biochemistry, University of California, Santa Barbara (2003)
I'm interested in how marine microbes interact with each other and how these interactions are mediated by cell-cell signaling. Because diatoms are among the most important primary producers in the oceans, I am investigating inter-species interactions between diatoms (eukaryotes) and the two other domains of life (prokaryotes): 1) bacteria and 2) archaea.
1) Diatom-bacterial interactions are common in the oceans and can be beneficial or lethal. Only a small number of these interactions have been described. One possible mechanism for a diatom to detect and respond to beneficial or "pathogenic" bacteria is through detection of a molecule the bacteria produce. Many marine bacteria use hydrophobic signals to communicate with each other (i.e. quorum sensing). Similar to some plants, diatoms maybe able to detect beneficial vs lethal bacteria by differentiating between their excreted molecular signals. Currently, I'm using whole transcriptome analysis to study this possible mechanism in diatoms.
2) Archaea have been typically associated with extreme environments such as hydrothermal vents. However, we now know that marine archaea dominate many parts of the marine environment and influence global biogeochemical cycles. For example, Ammonia-oxidizing Archaea (AOA) play an important role in the nitrogen cycle by oxidizing ammonia to nitrite. Their dominance in many marine habitats and presence in the upper water column (e.g. chlorophyll a maxima where phytoplankton thrive) suggest that they are likely to interact with other microbes including diatoms. Currently, I'm studying trace metal limitation of the only cultured marine AOA isolate with wider implications to diatom metal availability.
1) Amin, S.A.; Moffett, J.W.; Martens-Habbena, W.; Horak, R.E.A.; Qin, W.; Jacquot, J.; Devol, A.; Ingalls, A.; Beatteay, S.; Schauer, A.; Stahl, D.A.; Armbrust, E.V. Copper requirements of the ammonia-oxidizing archaeon Nitrosopumilus maritimus SCM1 and implications to nitrification in the marine environment. Submitted.
2) Carrano, C.J.;Amin, S.A.; Trimble, L.; Romano, A.; Hobusch, A.; Schroeder, K.; Hartnett, A.; Crumbliss, A. Regulation of iron transport related genes by boron in the marine bacterium Marinobacter algicola DG893. Metallomics Accepted .
4) Amin, S.A.; Green, D.H.; Gardes, A.; Romano, A.; Trimble, L.; Carrano, C.J. Siderophore-mediated iron uptake in two clades of Marinobacter spp. associated with phytoplankton: The role of light. BioMetals 2012, 25, 181-192.
5) Amin, S.A.; Green, D.H.; Al-Waheeb, D.; Gardes, A.; Carrano, C.J. Iron transport in the genus Marinobacter. BioMetals 2012,25,135-147.
6) Amin, S.A.; Green, D.H.; Kuepper, F.C.; Sunda, W.G.; Carrano, C.J. Photolysis of iron siderophore chelates promotes bacterial-algal mutualism. Proceedings of the National Academy of Sciences of the U.S.A. 2009, 106, 17071-17076.
7) Amin, S.A.; Green, D.H.; Kuepper, F.C.; Carrano, C.J. Vibrioferrin, an unusual marine siderophore: Iron binding, photochemistry and biological implications. Inorganic Chemistry 2009, 48, 11451-11458.
8) Zhang, G; Amin, S.A.; Kuepper, F.C.; Holt, P.D.; Carrano, C.J.; Butler, A. Ferric stability constants of representative marine siderophores: Marinobactins, Aquachelins, and Petrobactin. Inorganic Chemistry 2009, 48, 11466-11473.
9) Carrano, C.J.; Schellenberg, S.; Amin, S.A.; Green, D.H.; Kuepper, F.C. Boron and marine life: A new look at an enigmatic bioelement. Marine Biotechnology, 2009, 11, 431-440.
10) Harris, W.R.; Amin, S.A.; Kuepper, F.C.; Green, D.H.; Carrano, C.J. Borate binding to siderophores: Structure and stability. Journal of the American Chemical Society 2007, 129, 12263-12271.
11) Amin, S.A.; Kuepper, F.C.; Green, D.H.; Harris, W.R.; Carrano, C.J. Boron binding by a siderophore isolated from marine bacteria associated with the toxid dinoflagellate Gymnodinium catenatum. Journal of the American Chemical Society 2007, 129, 478-479.