Functional and Ultrastructural Analyses of Archaeal Cell Surface Appendages
Final Report Abstract
• We could show that the flagella of Pyrococcus furiosus not only act as motility organelles, adhesins and can mediate cell-cell connections, but also enable the cells to establish a structured biofilm, if grown in co-culture with Methanopyrus kandleri. Both species benefit in this coculture via an H2 symbiosis. In addition, our data demonstrate that P. furiosus not only can exert positive effects in co-culture with other methanogens; we also observed neutral and even inhibitory interactions. • First results using light microscopic analyses of swimming Archaea indicate that some of them are the fastest organisms observed today (if motility is expressed in “bodies per second”). These studies shall be extended in a new DFG project. • For the species Methanocaldococcus villosus which we have newly described, again the function of its flagella as adhesins was proven. A detailed comparison of flagella from Methanocaldococci revealed the unique composition of M. villosus flagella. Ultrastructural analyses of the flagella of M. villosus and P. furiosus using the method described below for I. hospitalis (cryoTEM, IHRSR) are underway in cooperation with Prof. Egelman. • Our studies of the fimbriae of Methanothermobacter thermoautotrophicus for the first time identified the structural gene of an archaeal fimbrin and proved the function of the fimbriae for adhesion and biofilm formation. The archaeal fimbrin gene could not be expressed directly in Escherichia coli; meanwhile we could define the archaeal fimbrin operon and learned that the fimbrin gene together with a neighbouring putative chaperon gene can be cloned in E. coli. • The so-called fibers of Ignicoccus hospitalis have been shown to constitute a new type of archaeal cell surface appendage; the fiber protein is not related to archaeal flagellins or fimbrins. Data by Meyer et al. again argue that the fibers are used for adhesion; a potential anchoring structure has been identified. In cooperation with Prof. Egelman (University of Virginia, USA) the 3D ultrastructure of the fibers was resolved to a resolution of ca. 8 Å; to the best of our knowledge this represents the highest resolution obtained today using electron microscopy and IHRSR calculations. The interaction of I. hospitalis with Nanoarchaeum equitans was analysed via proteomics and via ultrastructural analyses combined with 3D reconstructions. • Staining of archaeal cells with fluorescent dyes, subsequent re-culturing, and analyses of the dye distribution over time allowed us to ask for the mode of cell wall growth in Archaea. The data showed that the mode of cell wall growth is similar in Bacteria and Archaea: for rod-shaped organisms new cell wall material is incorporated in a “diffuse” manner over the cell length, whilst in cocci new cell wall material is incorporated in the septum region.
Publications
- 2008. An archaeal bi-species biofilm formed by Pyrococcus furiosus and Methanopyrus kandleri. Arch. Microbiol. 190:371-377
Schopf, S., G. Wanner, R. Rachel, and R. Wirth
(See online at https://doi.org/10.1007/s00203-008-0371-9) - 2008. Fimbriae of Methanothermobacter thermoautotrophicus are encoded by mth60: first characterization of an archaeal fimbrium. Env. Microbiol. 10:2785-2795
Thoma, C., M. Frank, R. Rachel, S. Schmid, D. Näther, G. Wanner, and R. Wirth
- 2008. Ignicoccus hospitalis and Nanoarchaeum equitans: Ultrastructure, cell-cell interaction, and 3D reconstruction from serial sections of freeze-substituted cells and by electron cryotomography. Arch. Microbiol. 190:395-408
Junglas, B., A. Briegel, T. Burghardt, P. Walther, R. Wirth, H. Huber, and R. Rachel
(See online at https://doi.org/10.1007/s00203-008-0402-6) - 2008. Insight into the proteome of the hyperthermophilic Crenarchaeon Ignicoccus hospitalis: the major cytosolic and membrane proteins. Arch. Microbiol. 190:379-394
Burghardt, T., M. Saller, S. Gürster, D. Müller, C. Meyer, U. Jahn, R. Deutzmann, P. Babinger, R. Wirth, H. Huber, and R. Rachel
(See online at https://doi.org/10.1007/s00203-008-0399-x) - 2009. The Iho670 fibers of Ignicoccus hosptialis: a new type of archaeal cell surface appendage. J. Bacteriol. 191:6465-6468
Müller, D., C. Meyer, S. Gürster, U. Küper, H. Huber, R. Rachel, G. Wanner, R. Wirth, and A. Bellack
- 2010. Analysis of the Ultrastructure of Archaea by Electron Microscopy. In: Methods In Cell Biology, Vol. 96, pp 47-69. T. Müller-Reichert (ed); Elsevier Inc.
Rachel, R., C. Meyer, A. Klingl, S. Gürster, T. Heimerl, N. Wasserburger, T. Burghardt, U. Küper, A. Bellack, S. Schopf, R. Wirth, H. Huber, and G. Wanner
- 2010. Methanocaldococcus villosus sp. nov., a heavily flagellated archaeon adhering to surfaces and forming cell-cell contacts. Int. J. of Syst. Evol. Microbiol.
Bellack, A., H. Huber, R. Rachel, G. Wanner, and R. Wirth
(See online at https://doi.org/10.1099/ijs.0.023663-0)
