Zelloberflächenstrukturen der Bacteria und Archaea

Die zellkernlosen Mikroorganismen werden in die beiden Domänen Bacteria und Archaea eingeteilt. Die dritte Domäne stellen die Eukarya. Es gibt kein universelles Zellwandpolymer, das bei allen Bacteria und Archaea vorkommt. Aufgrund der Morphologie können gewisse Zellwandtypen identifiziert werden, aber die chemische Vielfalt der einzelnen Polymere ist wesentlich größer. In diesem Beitrag werden einige wichtige Oberflächenpolymere der Bacteria und Archaea entsprechend ihrer chemischen Zusammensetzung vorgestellt. Cell wall types of Bacteria and Archaea The acaryote microorganisms are divided into the two domains Bacteria and Archaea. The third domain represent the Eukarya. There is no universal cell wall polymer found in all Bacteria and Archaea. Due to their morphology several cell wall types can be identified, but the chemical diversity of the individual polymers is considerably greater. Certain cell wall polymers are limited to one of the two domains of Bacteria or Archaea like the murein of the Bacteria or the pseudomurein of some methanogens. Peptidoglycans (murein, pseudomurein) do not occur in eukaryotes. On the other hand individual cell wall polymers possess similarities to polymers of other domains. The structural principle of the methanochondroitin is also implemented in the eukaryotic connective tissue. The cell wall polymers consist frequently of glycoconjugates in which the amino acid content (glycoproteins) or the glycan moiety (proteoglycan‐like polymers) predominate. Both components (carbohydrates, amino acids) can also occur in similar amounts (peptidoglycan). There exist also cell wall polymers, which consist only of glycans (slimes, methanochondroitin) or amino acids (proteins, poly‐γ‐D‐glutamyl polymers). Cell wall‐free species (Mycoplasma) also occur. The chemical composition of the cell surface polymers was one of the first phenotypic characteristics that supported the 16 sRNA concept of Carl Woese to assign acaryote organisms into the two domains Bacteria and Archaea. A common feature of all Archaea is the lack of muramic acid and an outer membrane. The later occurs in the gramnegative Bacteria. During the evolution of Bacteria and Archaea a great variety of chemically different cell wall polymers has been developed which allow the growth and interaction of Bacteria and Archaea in different habitats. In this paper, some important surface polymers of Bacteria and Archaea are presented according to their chemical composition. Die erste