Archaea and the third domain of Life
The biology of organisms that grow optimally under extreme conditions has been of considerable interest in recent years and especially of those organisms thriving at extremes of temperature, pH or high salt concentrations. Most of these organisms are Archaea not Bacteria or Eukarya.
Although Archaea are likely to constitute at least 20% of the planet's biomass, and to exert a major influence on the biosphere, less than 0.1% of Archaea have been cultured and characterized. At present we are rapidly increasing our knowledge about the cellular molecular biology, biodiversity and evolution of the Archaea, complementing studies on Bacteria and Eukarya which have both been studied extensively, albeit very selectively.
The Danish Archaea Centre (DAC) has a long term basic research program focused on understanding the basic molecular and cellular biology of Archaea and in characterising their archaea-specific and many proto-eukaryotic cellular mechanisms and processes. We have been working with members of the crenarchaeal hyperthermophilic Order of Sulfolobales as model organisms and with the euryarchaeal extreme halophilic genus Haloferax. Much of the current research is genome-based exploiting in-house developed genetic systems. Our major current interests (described here) extend from characterising the diverse archaeal viruses which, morphologically and genomically, are quite distinct from bacterial and eukaryal viruses to archaeal enzymes which are are useful for biotechnological and industrial processes because of their high stability to extremes of temperature, pH and salt.