Archaea are unicellular organisms best known for their ability to inhabit seemingly hostile environments, such as hot springs with acidic water at boiling temperatures. However, archaea are not confined to extreme conditions, but are in fact widespread across ecosystems, including the oceans and the human gut.

What makes studying archaea so fascinating is that they are not eukaryotes (which include us humans and all other animals and plants), nor are they bacteria. Instead, archaea constitute their own domain of life. While their appearance resembles that of bacteria in many ways, central aspects of their molecular biology are more similar to that of eukaryotes. Studying archaea can therefore tell us much about the evolution of life and of the fundamental biological processes that enable it.

The Molecular Biology of Archaea group researches several fascinating aspects of archaeal biology:

• Movement: We want to understand how the archaellum, a long, rod-like structure that archaea use to propel themselves forward, gets assembled on the cell surface. Additionally, we investigate the production other structural molecules of the outer envelope.
• Cell division: We want to identify the molecules and processes that enable the multiplication of archaea.
• Environmental sensing: We want to find out how small-molecule second messengers, specifically cyclic nucleotides, enable archea to react to their environment.

We study these processes using microscopy and genetic research techniques. We focus on two model species of archaea: the thermoacidophilic (latin: heat and acid-loving) crenarchaeon Sulfolobus acidocaldarius and the extremely halophilic (salt-loving) euryarchaeon Haloferax volcanii.