In Singulo Biophysics: accessing the Dynamics of Intracellular Processes at the Molecular and Cellular Levels

The understanding of the mechanisms behind the dynamics of biological processes is crucial to build a more comprehensive picture of the principles governing living systems. At the microscopic scale, local fluctuations and perturbations shape the dynamic behavior of these natural processes, demanding experimental access to the action of their individual players, e.g., biomolecules, supramolecular complexes, organelles. This thesis presents a variety of biophysical strategies based on advanced microscopy techniques to study biomolecular processes that are highly dynamic in essence. In particular, a combination of optical trapping, fluorescence microscopy, and atomic force microscopy was applied to describe diverse intracellular processes at the level of individual molecules and individual cells. The biological processes covered in this thesis are: the role of histone chaperones regulating histone-histone and histone-DNA interaction in the context of nucleosome remodeling; the thermodynamic and structural characterization of DNA encapsidation and nucleation intermediates in virus assembly; and the development of a method to investigate the kinetic responses of chemically activated macrophages with single-cell resolution. Overall, we report the detailed molecular and cellular behavior of the targeted biological systems with special emphasis in the underlying dynamics and energetics that lead to their specific biological functions.