Dr. Michael R. Gretz
Professor
Ph.D., Arizona State University

Research Area:

Algal Extracellular Polymers and Biocomposites

Research Description:

The primary focus of our research program is the extracellular matrix (ECM) of algae.These extracellular polymers are known to play active roles in a wide range of processes and have emerged as a central focus of studies of growth and development of algae/algal dominated systems. Support for this work has been provided primarily by National Science Foundation, Air Force Office of Scientific Research and Office of Naval Research grants and corporation contracts.

Three major projects are currently underway including studies of: 1) cell directed self-assembly of algal extracellular biocomposite structures; 2) functional relationships of extracellular polymers, microbial associations and physico-chemical parameters in freshwater and marine biofilms, and; 3) differential occurrence of land plant polymers within the charophycean green algae as related to the evolution of the land plant cell wall. Most recently, we have initiated a nanotechnology project concerning polysaccharide involvment in biosilicification (biologic production of "window glass") at the Scripps Institution of Oceanography.

We investigating mudflat biofilms of the Colne Estuary, U.K., a harmful diatom species with greatly enhanced ECM production from streams in western U.S and New Zealand, and desmid, diatom and cyanobacteria dominated biofilms from the Everglades and Michigan and New York bogs and beaver ponds.

Please visit our www site “THE WALL” to learn more about our work.

Current Publications:

• Kiemle, S.N., Domozych, D.S. and Gretz, M.R. 2007. The extracellular polymeric substances of desmids (Conjugatophyceae, Streptophyta): Structural analysis and implications in wetland biofilms. Phycologia (in press).
  
  
• Domozych, D.S., Elliott, L., Kiemle, S.N. and Gretz, M.R. 2007. Pleurotaenium trabecula, a desmid of wetland biofilms: The extracellular matrix and adhesion mechanisms. Journal of Phycology (in press).
  
  
• Bellinger, B.J., Underwood, G.J.C., Ziegler, S.E. and Gretz, M.R. 2007. The significance of diatom-derived polymers in carbon flow dynamics within estuarine biofilms determined through isotopic enrichment. Limnology & Oceanography (in press).
  
  
• Domozych, D.S., Serfis, A., Kiemle, S. and Gretz, M.R. 2007. The structure and biochemistry of charophycean cell walls. I. Pectins of Penium margaritaceum. Protoplasma.230:99-115.
  
  
• Abdullahi, A.S., Underwood, G.J.C., and Gretz, M.R. 2006. Extracellular matrix assembly in diatoms (Bacillariophyceae). V. Effects of phosphate levels and salinity on polysaccharides of Phaeodactylum tricornutum. Journal of Phycology 42:363-378.
  
  
• Apoya, M.D., Yin, L., Underwood, G.J.C. and Gretz, M.R. 2006. Movement modalities and responses to environmental changes of the mudflat diatom Cylindrotheca closterium. Journal of Phycology 42:379-390.ont>
  
  
• Hanlon, A.R.M., Bellinger, B.J., Xiao, G., Haynes, K, Ball, A.S., Osborn, M., Gretz, M.R., and Underwood, G.J.C. 2006. Dynamics of EPS production and loss in an estuarine, diatom-dominated microalgal biofilm over a tidal emersion-immersion period. Limnology & Oceanography.51:79-93.ont>
  
  
• Bellinger, B.J., Abdullahi, A.S., Gretz, M.R. and Underwood, G.J.C. 2005. Biofilm Polymers: Relationship between carbohydrate biopolymers from estuarine mudflats and unialgal cultures of benthic diatoms. Aquatic Microbial Ecology.38:169-180ont>
  
  
• Subhash, G., Yao, S., Bellinger, B. & Gretz, M.R. 2005. Investigation of mechanical properties of diatom frustules using nanoindentation. Journal of Nanoscience and Nanotechnology 5:44-50.