jonathan markham, ph.d. assistant research member
jmarkham@danforthcenter.org
I am interested in the metabolism of sphingolipids and the generation of cellular signals through the sphingolipid metabolic pathway.
Sphingolipids are special lipid compounds that interact with some very basic life processes, such as helping to organize the internal contents of a cell, or deciding whether a cell should grow and multiply or stop dividing and die. As a result of these interactions, the impact sphingolipids can have on the fate of a cell or an entire organism may dramatic. By uncovering the details of sphingolipid metabolism, we aim to discover how sphingolipids have become so intricately woven into the life and death of the cell.
My research uses advanced mass-spectrometry techniques to measure sphingolipids from plants. In collaboration with national and interna- tional research groups we have demonstrated how variation in sphingo-
recent publications: Roudier, F., Gissot, L., Beaudoin, F., Haslam, R., Michaelson, L., Marion, J., Molino, D., Lima, A., Bach, L., Morin, H., Tellier, F., Palauqui, J.C., Bellec, Y., Renne, C., Miquel, M., Dacosta, M., Vignard, J., Rochat, C., Markham, J.E., Moreau, P., Napier, J., Faure, J.D. (2010) Very-long-chain fatty acids are involved in polar auxin transport and developmental patterning in Arabidopsis. Plant Cell 22:364-75 Beaudoin, F., Wu, X., Li, F., Haslam, R.P., Markham, J.E., Zheng, H., Napier, J.A., Kunst, L. (2009) Functional Characterization of the Arabidopsis {beta}-KetoAcyl-
lipids structure or control of metabolism has profound effects on plant growth, development, cell division, response to disease and cell death. Over the past year we have moved beyond looking at the sphingolipids of known mutants and isolated new mutants with abnormal sphingolipid content by high-throughput screening. Tis has produced numerous novel mutants of sphingolipid metabolism, some in known genes and others in genes that have yet to be identified. Discovery of the genetic abnormality in these new mutants will open new doors for understanding the biology of sphingolip- ids and their role in vital plant processes.
Coenzyme A Reductase Candidates of the Fatty Acid Elongase. Plant Physiol. 150:1174-91 Michaelson, L.V., Zaeuner, S., Markham, J.E., Haslam, R., Desikan, R., Mug- ford, S., Albrecht, S., Warnecke, D., Sperling, P., Heinz, E., Napier, J. (2009) Functional characterisation of a higher plant sphingolipid 4-desaturase: defining the role of sphingosine and sphingosine-1-phosphate in Arabidopsis thaliana. Plant Physiol. 149:487-98
monica schmidt, ph.d. assistant research member
mschmidt@danforthcenter.org
Age-related macular degeneration (amd) is the leading cause of irrevers- ible vision loss in Americans 55 years of age and older and is estimated to currently affect 10 million Americans. Although there is no effective treatment for amd, recent studies have indicated a diet rich in vegetable- borne carotenoids, such as zeaxanthin, can prevent or reduce the risk of amd. Average intake of zeaxanthin in the U.S. is below levels associated with eye disease prevention. Zeaxanthin can be produced from a single biochemical reaction using β-carotene as a substrate. We have already been successful at the production of nearly 900 μg/g β-carotene in soybean seeds and now we are working on furthering the carotenoid pathway in soybean seeds to bio-fortify them with zeaxanthin.
lab members: Colin Clune / Melanie Kessler-Mathieu, PhD
recent publications: Semenyuk, K., Moravec, T., Schmidt, M.A. Beachy R.N., Woodford- Tomas, T. (2010) Adaptation of an ecdysone-based genetic switch for transgene expression in soybean seeds. Transgenic Research (in press). Herman, E.M. and Schmidt, M.A. (2010) Industrial protein production crops. GM crops 1: 1-6 (cover) Herman, E. M. and Schmidt, M.A. (2009) Improved protein storage in plants (provisional patent filing, US and International) Semenyuk, K., Schmidt, M.A., Woodford-Tomas, T. and Moravec, T. (2009) Engineering seeds for the production and delivery of oral vaccines. In Modification of seed composition to promote health and nutrition. American Society of Agronomy. H. Krishnan (ed) pp.121-150.
page 24 2009 scientific report the donald danforth plant science center
Schmidt, M.A. and Herman, E.M. (2008) Te Collateral Protein Compen- sation Mechanism Can Be Exploited To Enhance Foreign Protein Accumu- lation In Soybean Seeds. Plant Biotechnology 6: 832-842. Schmidt, M.A. and Herman, E.M. (2008) A RNAi knockdown of soybean 24 kda oleosin results in the formation of micro-oil bodies that aggregate to form large complexes of oil bodies and ER containing caleosin. Molecular Plant 1: 910-924. Schmidt, M.A., Lafayette, P.R., Artelt, B.J. and Parrott, W.A. (2008) A comparison of strategies for transformation with multiple genes via microprojectile-mediated bombardment. In Vitro Cellular and Develop- mental Biology – Plants 44: 162-168.
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