Functional and Ultrastructural Analyses of Archaeal Cell Surface Appendages

• Applicant: Professor Dr. Reinhard Wirth
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 32112545

Many Bacteria possess long thin filaments on their cell surface, which are named flagella or fimbriae according to their (proposed) function as motility organelle or adhesive organelle. Detailed data exist as to the mechanism of motion and the ultrastructure of the bacterial motility organelles and fimbriae. Cell surface appendages similar to bacterial flagella and fimbriae were also observed on many Archaea, but only in a very few cases (ultra)structural and functional analyses have been reported. In this project we want to analyse flagella and fimbriae of various Archaea with respect to their structure and function. Functional analyses will include direct observation and visualization of motile cells and/or adherent cells using fluorescence-staining of cells and their appendages, a technique which recently could be adopted in our lab for various Archaea like Pyrococcus furiosus (a hyperthermophilic Archaeum) and Methanothermobacter thermoautotrophicus (a methanogenic Archaeum). Motility will be analysed using a so-called thermo-microscope and a CCD-camera, allowing in situ visualisation of cells under anaerobic conditions at temperatures up to 95° C. The structural characterisation of flagella and fimbriae will include determination of their 3-D structure via electron tomography, identification of flagellar and fimbrial protein subunits, their biochemical analysis and localization of the subunits via immune electron microscopy. In addition we want to ask for structural components which serve as motors and/or anchors for archaeal flagella/fimbriae using ghosts of lysed cells which still have flagella/fimbriae attached to the envelopes.

• DFG Programme: Research Grants
• Participating Person: Professor Dr. Reinhard Rachel