Lichtgedanken 03

S C HW E R P U N K T 16 fectious diseases and to do everything possible to stop them from spreading. However, we must not forget that the vast majority of microbes are comple- tely harmless to us or are even useful. There are an estimated three to five mil- lion fungus species, of which only 150 are known to be pathogens. And what is more, we live off microbial products: we eat bread, cheese and yoghurt—and we drink alcohol ( he laughs ). So, does that mean we need microorga- nisms more than they need us? That means that the coexistence, the interaction between microorganisms and humans or other higher organisms is the result of millions of years spent evolving together. We are mutually de- pendent on one another. What is cer- tain is that microorganisms were the first organisms on Earth—and they will probably be the last. The evolution of all higher organisms always involved interaction with microorganisms and this continues in the present day. We can see this in our immune system, for example, which would not even exist without microorganisms. We have a multitude of immunoreceptors, which exist exclusively to interact with various different microorganisms, because these can be either dangerous or useful to us. This means that in the course of time, microorganisms have formed and chan- ged us, just as we have also formed the microbial communities. Similar exam- ples can also be found in plants, which have used the interaction with microor- ganisms to develop efficient defence strategies. There is a constant competi- tion between microbes and higher orga- nisms. What challenges must microbiological research therefore meet in the future? What we have achieved to date is a comprehensive analysis of microbi- al communities. We can sequence and compare their genomes and their me- tabolisms, their proteins and natural products. We can precisely describe the organisms and the consortia they form. But describing is far from understan- ding. The next research step therefore consists of function analyses. In order to understand why microbes coexist in one composition or another and what influence they have on their environment and on their hosts, such as humans, plants and animals, we have to conduct mechanistic analyses. For this, we need a panoply of new me- thods: good computer model systems in order to perform simulations; and new methods of optical and chemical analysis, with which we can observe the vital processes within the organis- ms in real time and in situ (in their real surroundings). We want to image sing- le cells and molecules with the highest resolution possible and be able to see how individual microbes »talk« to one another and to us. And materials scien- tists are also required, because we need artificial cells and organs, which we can use to study and manipulate microbial communities. These are major research goals for the years to come and in Jena we are well- placed to pursue them. We expect this research to yield decisive findings for the treatment of diseases, for agriculture and for environmental protection. Microscopic world with spruce (see also cover photograph): At the Institute for Microbiology, scientists study the interaction between tree roots and fungi.