Lawrence Shimkets
Professor of Microbiology
Ph.D. (1980) University of Minnesota
Phone: 706-542-2681
Email: shimkets@uga.edu
See my Laboratory Home Page

Research Interests
Myxobacteria are one of the most ancient groups of organisms to exhibit multicellularity and engage in social behavior. Though they are members of the Proteobacteria, their large genome size and unusual social behaviors suggest a complex evolutionary history. During vegetative growth groups of cells live in a multicellular biofilm community where they prey on other bacteria as a food source. When deprived of nutrients myxobacteria initiate a developmental cycle in which tens of thousands of cells build a fruiting body containing myxospores. Developing cells respond to a variety of cell-cell signals to activate developmental genes according to a temporal and spatial program prescribed in the DNA. We study two contact-dependent cell-cell signaling systems with Myxococcus xanthus. One utilizes the CsgA (C signaling) protein, which acts as a developmental timer to couple gene expression with morphological development. The other signaling system utilizes phosphatidylethanolamine containing the fatty acid C16:1?5c as a chemoattractant. The extracellular matrix helps to process information concerning the phospholipid composition of adjacent cells. We use genetics, molecular biology, and biochemistry to study the signal transduction pathways.
  • Bonner P.J., Xu Q., Black W.P., Li Z., Yang Z.M. and L.J. Shimkets. 2005. The Dif chemosensory pathway is directly involved in phosphatidylethanolamine sensory transduction in Myxococcus xanthus. Molecular Microbiology 57: 1499-1508.
  • Simunovic, V., Gherardini, F.C. and L.J. Shimkets. 2003. Membrane localization of motility, signaling, and polyketide synthetase proteins in Myxococcus xanthus. Journal of Bacteriology 185: 5066-5075.
  • Brofft, J.E., McArthur, J.V. and L.J. Shimkets. 2002. Recovery of novel bacterial diversity from a forested wetland impacted by reject coal. Environmental Microbiology 4: 764-769.
  • Phillips R.W., Wiegel J., Berry C.J., Fliermans C., Peacock A.D., White D.C. and L.J. Shimkets. 2002. Kineococcus radiotolerans sp nov., a radiation-resistant, Gram-positive bacterium. International Journal of Systematic and Evolutionary Microbiology 52: 933-938.
  • Kearns D.B., Bonner P.J., Smith D.R. and L.J. Shimkets. 2002. An extracellular matrix-associated zinc metalloprotease is required for dilauroyl phosphatidylethanolamine chemotactic excitation in Myxococcus xanthus. Journal of Bacteriology 184: 1678-1684.
  • Lancero H., Brofft J.E., Downard J., Birren B.W., Nusbaum C., Naylor J., Shi W.Y. and L.J. Shimkets. 2002. Mapping of Myxococcus xanthus social motility dsp mutations to the dif genes. Journal of Bacteriology 184: 1462-1465.
  • Kearns D.B., Venot A., Bonner P.J., Stevens B., Boons G.J. and L.J. Shimkets. 2001. Identification of a developmental chemoattractant in Myxococcus xanthus through metabolic engineering. Proc. Natl. Acad. Sci., USA 98: 13990-13994.
  • Bonner, P.J. and L.J. Shimkets. 2001. Piecing together a puzzling pathway: new insights into C-signaling. Trends in Microbiology 9: 462-464.
  • Kearns, D.B. and L.J. Shimkets. 2001. Directed movement and surface-borne motility of Myxococcus and Pseudomonas. Methods in Enzymology 336: 94-102.
  • Kearns, D.B. and L.J. Shimkets. 2001. Lipid chemotaxis and signal transduction in Myxococcus xanthus. Trends in Microbiology 9: 126-129.
  • Wise, M.G., McArthur, J.V. and L.J. Shimkets. 2001. Methylosarcina fibrata gen. nov., sp nov and Methylosarcina quisquiliarum sp nov., novel type I methanotrophs. International Journal of Systematic and Evolutionary Microbiology 51: 611-621.
  • Kearns, D.B., Robinson, J. and L.J. Shimkets.2001. Pseudomonas aeruginosa exhibits directed twitching motility up phosphatidylethanolamine gradients. Journal of Bacteriology 183: 763-767.
  • Kearns, D.B., Campbell, B.D. and L.J. Shimkets. 2000. Myxococcus xanthus fibril appendages are essential for excitation by a phospholipid attractant. Proc. Natl. Acad. Sci., USA 97: 11505-11510.
  • Yang Z.M., Ma X.Y., Tong L.M., Kaplan H.B., Shimkets L.J. and W.Y. Shi. 2000. Myxococcus xanthus dif genes are required for biogenesis of cell surface fibrils essential for social gliding motility. Journal of Bacteriology 182: 5793-5798.
  • Crawford, E.W. and L.J. Shimkets. 2000. The Myxococcus xanthus socE and csgA genes are regulated by the stringent response. Molecular Microbiology 37: 788-799.
  • Crawford, E.W. and L.J. Shimkets. 2000. The stringent response in Myxococcus xanthus is regulated by SocE and the CsgA C-signaling protein. Genes and Development 14: 483-492.
  • Wise, M.G., McArthur, J.V. and L.J. Shimkets. 1999. Methanotroph diversity in landfill soil: Isolation of novel type I and type II methanotrophs whose presence was suggested by culture-independent 16S ribosomal DNA analysis. Applied and Environmental Microbiology 65: 4887-4897.
  • Shimkets, L.J. 1999. Intercellular signaling during fruiting-body development of Myxococcus xanthus. Annual Review of Microbiology 53: 525-549.
  • Kearns, D.B. and L.J. Shimkets. 1998. Chemotaxis in a gliding bacterium. Proc. Natl. Acad. Sci., USA 95: 11957-11962.
  • Leff, L.G., McArthur, J.V. and L.J. Shimkets. 1998. Persistence and dissemination of introduced bacteria in freshwater microcosms. Microbial Ecology 36: 202-211.
  • “Myxococcus xanthus Lipid Chemotaxis,” NSF