In
the Quax group we are interested in interactions between archaea and their
viruses. Archaea are ubiquitous microorganisms that form a separate domain of
life. They can colonize very different environments ranging from the human gut and
the world oceans to hydrothermal vents and hyper saline lakes. Compared with bacteria and eukaryotes,
relatively little is known about the cell biology and ecological roles of
archaea. A prominent feature of archaea is the extraordinary diversity of their
viruses. Archaeal viral particles have many unique shapes not encountered for
bacterial and eukaryotic viruses, such as a spindle, a spiral or a bottle. Viruses
are estimated to outnumber their hosts at least by a factor ten, and therefore
form a serious threat for archaeal cells. Archaeal viruses are important
players in deep-sea ecosystems and biochemical cycles, as they are responsible
for the cell-lysis induced release of considerable amounts of CO2. We focus on
the infection strategies of archaeal viruses and study the molecular mechanisms
underlying essential steps of the viral infection cycle, such as attachment,
entry and release of the host cell. Since these processes take place at the
cell surface, we are also actively studying the archaeal cell surface and surface
appendages using the halophilic euryarchaeon Haloferax volcanii as a model. Studying the infection mechanisms of
archaeal viruses can provide insight into the evolutionary history of viruses
and help to understand adaptation to extreme environments.