The way organisms develop from the initial single-cellular state to a complex final assembly like the human body, and how the final body is maintained throughout life, is one of the greatest... Show moreThe way organisms develop from the initial single-cellular state to a complex final assembly like the human body, and how the final body is maintained throughout life, is one of the greatest mysteries and it’s understanding one of the biggest scientific challenges. Lately, it came as a surprise that the initial assembly and the later maintenance of integrity is not only determined by intricate biochemical communication networks, but in part by physical forces that cells, their neighbors, and their environment apply in a bidirectional manner. The resulting collectivity of cell behavior determines the development of organisms, and are crucial to the health and disease state of the organism.In this thesis, we developed and utilized concepts from physics to quantitatively understand forces that develop between cells and their environment, and towards neighboring cells, and how the interplay between these forces regulates the arrangement, shape, and topology of tissue. The topics range from the development of novel experimental methods to the combination of experimental observations with theoretical descriptions. Our results contribute to a better understanding of cell and tissue integrity. Show less
Life’s building block is a cell. Different cell types are differentiated by specific functional properties. A white blood cell, for instance, can get rid of bacteria and many muscle cells contract... Show moreLife’s building block is a cell. Different cell types are differentiated by specific functional properties. A white blood cell, for instance, can get rid of bacteria and many muscle cells contract together for proper muscle function. Deformation and force exertion play important roles in these processes. Bacteria have to be physically engulfed by the white blood cell, and the muscle cell has to contract in the right way. In this research we measured how much force cells exert and simultaneously visualized specific proteins. A newly developed technique enabled the visualization of the nanometer-structure of cellular adhesions. We also examined the relationship between cellular shape and orientation of an intracellular network of protein (actin). We discovered that the signal of yet another protein (p130Cas) alters the mechanical behavior of the cell when the stiffness outside the cell changes. Finally, we also examined the structure of other proteins (tubulin and H2B) during cell division. In all these processes we measured how much force a cell exerts on its environment. The results provide important insights in the mechanical component of cellular function and their role in life Show less
