Lichtgedanken 03

S C HW E R P U N K T 12 biologists and chemists are studying the interactions between the freshwater alga Chlamydomonas reinhardtii (see p. 33) and various bacteria, among other things. Researchers at the Institute of Inorganic and Analytical Chemistry are focusing on marine diatoms and studying the influence of chemical signal molecules on their way of life, reproduction or susceptibility to viruses. Geoscientists and ecologists are also on the trail of microbial life in groundwater (see p. 36). Humans as habitat Microorganisms not only colonize every habitat on Earth, but also live on, and in equilibrium with, virtually every higher organism, including humans. We are all walking »ecosystems«. Every one of us carries about a kilo of microbial biomass on and in our bodies (see interview p. 14). The intestines in particular are colo- nized by several hundred species of bac- teria, archaea and fungi, with comple- tely individual compositions in every organism. The microbes living inside us help with our digestion, breaking down indigestible food for us, for example. They also support our immune system, produce vitamin K, which is essential for blood coagulation, and break down harmful substances. Research groups in Jena are looking at the pathogenesis of systemic fungal infections (see p. 18), identifying and characterising novel active substances from nature for the treatment of infec- tions (see p. 30) and developing, in in- terdisciplinary research consortia, new methods of diagnosing and treating se- rious infectious diseases which can lead to sepsis (see p. 20 and p. 24). F E AT U R E