Luis Vidali, assistant professor of biology and biotechnology at Worcester Polytechnic Institute (WPI), has won a five-year, $977,000 CAREER Award from the National Science Foundation (NSF) to explore polarized cell growth, a process critical to many vital functions in animals, plants and fungi. Cells typically grow by expanding outward in all directions, but many critical biological functions – including the development of root hairs in plants, budding in yeast and the extension of axons in animal neurons – require cells to grow in a single direction. Biologists have known for several decades which structures within the cell appear to participate in this polarized growth; however, exactly how those components work together to achieve this complex function remains a mystery. Vidali will study polarized growth in Physcomitrella patens, a moss that has filamentous cells that grow only at the tip. He will employ a combination of genetic techniques, advanced microscopy and computer simulations to attempt to compile a complete picture of how actin, myosin and vesicles work in concert to deliver materials the cell needs to build a new cell membrane and a new cell wall (a rigid structure that surrounds the cell membrane in plants, bacteria, fungi and algae) to the proper locations. Vidali and his team will use a variety of microscopy techniques to image the interplay between the cytoskeleton, myosin motors and vesicles. Electron microscopes can image these minute structures in great detail, but the resulting images are the equivalent of out-of-context snapshots because the cells must be killed before they are imaged. Confocal microscopes are not as powerful, but can record sequences of 3-D images. Total internal reflection fluorescence (TIRF) microscopes can achieve high resolution with a thin layer of a sample. The confocal and TIRF images will contribute to both spatial and temporal resolution.