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uni'wissen 02-2015_ENG

Some like it hot, and others even hotter. Some organisms, like the heat-loving archaea, feel right at home at temperatures between 80 and 120 degrees Celsius. The unicellular organisms measure a mere one micrometer on average, have no cell nucleus, and inhabit extreme living spaces like salt lakes, high-pressure deep sea vents, or highly acidic habitats. “They used to be known as archaebacteria,” says Prof. Dr. Sonja-Verena Albers, professor of microbiology at the University of Freiburg since September 2014. “Scientists long believed that archaea can only exist under severe conditions like these.” Albers heads one of five research groups distributed over the entire world that have set themselves the goal of elucidating the surface structure of these unusual organisms with the help of molecular tools. General interest in archaea grew when it turned out that they do not live only in extreme habitats but may also be found in the intestines and on the skin of humans, yet never cause diseases there. “It is difficult to explain why many bacteria ended up becoming pathogenic but not a single archaeon,” says the scientist. When it became clear that a particular substance in human blood increases the risk for heart disease, researchers made a surprising discovery: archaea are the only organisms that grow on this blood compo- nent and are therefore capable of reducing its concentration. Scientists are also discussing what role archaea play in diets. “They increase visibly in numbers when people start a fasting cure,” says Albers. Methanogenic archaea are also the only organisms that produce methane in mammalian intestines through metabolism. The gas is then released into the environment when we breathe, where it is a known climate factor. The sulfur- and acid-loving archaeon Sulfolobus acidocaldarius lives in hot springs at Yellowstone National Park at temperatures between 70 to 90 degrees Celsius. Photo: private „A whip made of protein filaments that works similarly to a propeller: Archaea move with the help of filament-like structures. Source: Sonja-Verena Albers 29uni wissen 02 2015 29uni wissen 022015