A genome contains all the information that is needed to build an organism like, for instance, a bacterium. One of functional genomics’ central questions is: How are these blueprints implemented so that relatively simple molecular codes ultimately give rise to a microorganism with the potential of getting us sick? What are some of the underlying mechanisms and under what conditions do they become activated?
The primary research focus of scientists working in the Microbial Proteomics Research Group is on the human pathogen Staphylococcus aureus. This bacterium colonises the skin and anterior nares of just about one third of the population – quite naturally and without ever causing any symptoms.
Despite the fact that S. aureus infections are relatively rare, today, multi-resistant strains of staphylococci are counted among the World’s most feared hospital germs that are responsible for roughly one third of all hospital infections. Multi-resistant strains of staphylococci no longer respond to treatment with conventional antibiotics and thus frequently lead to death of a patient. This is why it is important that new treatment strategies for this pathogen be developed that can readily be implemented in the clinical setting. To this end, an in-depth knowledge of this pathogen’s pathophysiology and virulence is urgently warranted – which is the reason why our scientists are specifically looking at identifying the link between the pathogen’s physiology and its knack for colonizing its host and causing disease.
The true effectors inside a cell are proteins. In addition to a systematic investigation of protein synthesis and degradation in bacterial cells, our scientists are interested in learning about how these molecules can be modified. As these proteins are key to the bacterium's interaction with its host, HZI scientists are also trying to shed light on these molecules' activity and on the jobs they perform. In order to document and study the total of bacterial proteins under pre-specified conditions and at specific points in time within a closed system, our scientists are drawing on a range of different research tools. With the help of mass spectrometry, they are able to document some 80 percent of bacterial proteins whose existence has been theoretically deduced based on the genome sequence. Using appropriate methods of preparation, proteins are assigned to specific cellular compartments and quantified.
This way, cytoplasmic proteins can be easily distinguished from membrane and surface bound or even secretory proteins. Any change in terms of quantity or type of modification can be analyzed. Our researchers are using these tools to study the regulation and function of different virulence factors in S. aureus. They are looking at how S. aureus adapts to situations of stress and starvation and to exposure to antibiotics. Another research focus is on different mechanisms bacteria use to adapt to their host as well as on developing test systems for identifying antibodies and potential targets of the S. aureus virulence factors in the host.