Microbiology/infection biology is one of five research priorities at the University of Tübingen. Expertise in this field will also be brought into the “Molecular Mechanisms of Bacterial Survival Strategies” research training group funded by the German Research Foundation (DFG) at the University of Tübingen. The research training group (GRK 1708) begins in April 2012 and involves twelve research groups with biological, geological, clinical and organochemical skills. The DFG will provide funding of a total of 2.1 million euros for a period of four and a half years to cover scholarships, material resources and education and training courses. The research training group is eligible for another funding round of 4.5 years following successful evaluation after the initial funding period.

“Bacteria are virtually omnipresent. They have an outstanding ability to adapt to most habitats on earth and we are now going to look in detail at the question as to how they are able to do this,” said Prof. Dr. Karl Forchhammer, spokesperson of the new research training group and professor at the Interfaculty Institute of Microbiology and Infection Medicine (IMIT) at the University of Tübingen. Forchhammer explains that the GRK’s topic was deliberately kept as general as possible so that any new and interesting aspects that may arise can be dealt with in detail. As research into bacterial survival strategies is an emerging area, Forchhammer is convinced that many new aspects will be discovered.

"Comprehensive information is available about bacterial habitats and what bacteria need for growth. However in nature, bacterial growth tends to be a state of emergency rather than a normal activity. Up until now, research has mainly focused on the state of emergency, and has led to negative consequences in a highly prominent case - the EHEC infections that occurred in spring 2011. "It was little known that Escherichia coli was also able to survive in plant spores; hardly any research had been done on such bacterial habitats. Bacterial "default mode" is set to nutrient deficiency, which leads to a growth-limiting state during which bacteria are able to survive in the most unusual habitats," explained Forchhammer.

The exponential growth of bacteria has led to the evolution of sophisticated bacterial survival strategies. Exponential growth leads to a rapid increase in cellular mass and is associated with a rapid decrease in nutrient resources. "In natural environments, nutrients are limited and bacteria cannot reproduce indefinitely. The permanent state of "hunger" is only interrupted when nutrients become available. Even bacteria in the human intestines starve most of the day," said Forchhammer. "Bacteria have developed a broad range of different hunger- and stress-related survival strategies; however, the fundamental ability to survive limited nutrient conditions must have been determined at a very early stage during evolution. Therefore, we expect different bacteria to have common survival strategies," Forchhammer continued.

Bacterial survival abilities can be divided into detoxification mechanisms, repair metabolisms, and the formation of protective and antibiotic substances, all of which lead to the maintenance metabolism that will be covered in the GRK projects. The researchers from Tübingen will focus specifically on intracellular protective proteins and envelope substances, as well as secondary metabolites with an antibiotic effect that are actively secreted to give the bacteria a survival advantage. A key aspect of all the investigations relates to the point in time when the bacteria switch from growth to maintenance as this is the point when key regulatory mechanisms are induced.

As far as the bacterial groups are concerned, the projects will be roughly divided into two subgroups: projects that will deal with human and animal pathogens and projects that will deal with environmentally relevant bacteria. Forchhammer's research concentrates on cyanobacteria; his GRK project will focus on the photosynthetic bacterial metabolism when little nitrogen is available. "The lack of nutrients leads to a drastic reduction of photosynthetic activity; it is reduced to as little as one promille. Our objective is to investigate the cyanobacterial "photosynthesis stand-by" in greater detail," said Forchhammer.

Other projects will focus on the bacterial survival strategies in biofilms and the protective effect of iron mineral envelopes of iron-oxidising bacteria, which is an issue dealt with in geomicrobiology. Another group of researchers will be concentrating on the adaptation strategies that enable staphylococcae to survive on human skin despite the presence of antimicrobial fatty acids. And other projects will focus on the genes that enable E. coli to survive in the human intestines and genes that protect them against death during inflammatory situations, and on the chemistry of actinomycetes, which are plant pathogens.

Forchhammer believes that the research training group was granted funding at just the right time. “Over the last ten or 15 years, the field of analytics has revolutionised and we are now able to investigate bacteria on the single cell level, something that was previously unthinkable. The topics we wanted to work on were easy to pick as much cellular behaviour is known and needs to be investigated.” The research training group will advertise the doctoral positions and grants in international journals at the end of 2011 and encourages young scientists to apply for projects they are interested in. “We will take particular care to recruit excellent students as the success of research training groups very much depends on the people factor,” said Forchhammer, who is looking forward to hearing from suitably qualified applicants.

Further information:

University of Tübingen
Prof. Dr. Karl Forchhammer
Department of Microbiology/Organismic Interactions
Auf der Morgenstelle 28, 72076 Tübingen
Tel.: +49 (0)7071/ 29 - 72 096
E-mail: karl.forchhammer(at)uni-tuebingen.de