Max Planck Institutes and Experts

Atmospheric chemistry does not stop at sunset but continues via the formation and reactions of the NO₃ radical. Whilst this dark chemistry is distinct from that during the day, the day-night systems are strongly coupled. Understanding the present composition of the troposphere and the ability to predict the impact of increasing anthropogenic emissions in the future require detailed understanding of the multifarious gas-phase and heterogeneous processes, both night and day.

An increasing world population and fast spread of old and new influenza virus strains demands more efficient vaccine production methods. One approach is the use of coupled continuous bioreactors. Unfortunately, accumulation of defective interfering particles (DIPs) leads to unstable virus yields. As an alternative we have designed a novel plug-flow tubular bioreactor system, providing high influenza virus titers for up to three weeks in continuous mode using suspension MDCK cells. This novel platform can be used for other viruses and help reduce vaccine manufacturing costs worldwide.

Active and directed fluid transport are crucial for the survival of eukaryotic organisms. This is often carried out by ciliated tissues e. g., the inner wall of the ventriclar system in the mammalian brain. Using a novel method the complexity of the cilia driven fluid flow in the third ventricle of the brain is revealed. Furthermore, ciliated tissues, which are capable of driving such complex flows are interesting for synthetic biology and applications in technology. Therefore, our working group at the MPI for Dynamics and Self-Organization currently attempts to rebuild such ciliated carpets.

Many pathogenic bacteria, for example Neisseria gonorrhoeae, form microcolonies, aggregates consisting of up to several thousands of cells, due to type IV pili. These filaments mediate attractive cell-cell-forces that affect the spatially-dependent dynamics of cells within the colony. This dynamic heterogeneity can then give rise to an altered gene expression pattern in the microcolony and thus changing the phenotypes of the cells. This behavior is reminiscent of early embryonic development and suggests a view on bacterial microcolonies as model multicellular organisms.

Analysis of chemical bonding in compounds of the MgAgAs type of structure by bonding indicators in position space resulted in a generalization of the 8­–N rule for bonds of variable polarity. Position-space indicators enable quantification of ionicity and covalence, which was successfully used to explain the different site preference in main-group and transition-metal compounds of the MgAgAs type. On this basis, it was possible to propose promising candidates for new compounds with the MgAgAs structure type, which was subsequently verified for the majority of compounds by laboratory synthesis.