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EP: Extraterrestrische Physik

EP 14: Leben und Lebensbedingungen ausserhalb der Erde II

EP 14.10: Vortrag

Mittwoch, 22. März 2000, 18:00–18:15, N3110

Cell wall polymers in Archaea (Archaebacteria) — •Helmut König — Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität, 55099 Mainz

The designation “Archaea” was given to a group of prokaryotes, which was recogni-zed as a separate third domain of life with the Bacteria and Eucarya. The Archaea in-habit niches reminding one of the archaic conditions of the early earth. The Archaea exhibit some unique characteristics. Unlike most Bacteria they possess no universal cell wall polymer. Frequently, single layers of (glyco-)proteins are formed. These pro-teinaceous subunits form primitive cell envelopes, which represent an early invention of the Archaea. Our knowledge about the adaptation of proteins to extreme environ-mental conditions is premature and the molecular basis of acidophily, alkalophily or barophily is still obscure. The molecular mechanisms making life possible under such extreme conditions with high temperature, high salt concentrations or low pH values are not understood. No general conclusions can be drawn regarding the stabilizing mechanisms. The cell envelopes of Archaea are directly exposed to the extreme en-vironments and can not be stabilized by cellular components. Therefore, they may serve as a model to elucidate survival strategies of these unusual microorganisms