Pneumococcal cell biology in a new light

Although bacteria can be found almost everywhere, we cannot see them with the naked eye. For that we can use microscopes: to magnify small things and make them visible to us. Bacteria grow by binary fission, where one cell is dividing into two identical copies of itself. Most bacteria are important if not indispensable for us and our environment. A few, however, can cause diseases. For instance Streptococcus pneumoniae (the pneumococcus), which has the shape of a rugby ball, can lead to severe infections of the respiratory tract. Since Fleming’s discovery of penicillin in the 1920s, antibiotics have been used to cure bacterial infections. The increase in antibiotic-resistant pathogens has progressively turned into a serious problem. In order to identify new drug targets it is essential to understand the basis of bacterial growth. The division of a cell is a highly dynamic process that requires a (fine-tuned) interplay of many factors. Our approach was to investigate these processes, by directly looking at single cells with microcopy techniques. We can use fluorescent proteins to label other proteins and then directly observe the localization within the living cell. Part of our work describes optimized methods and tools for fluorescence microscopy that are of general interest in the field. We were also able to shed some light on the regulation of division processes, but yet more work is needed in order to get a clearer picture and identify novel antibiotics that target the pneumococcus.