Condensed Matter/Materials & Biological Physics Seminar with Enrique Rojas on Smart fungal and bacterial materials

I will talk about two cases where microbial cells dynamically manipulate their mechanical properties in order to execute robust growth and morphogenesis.  First, we discovered that fungal hyphae spatially pattern the mechanical properties of their surface to execute their growth via inflation of the cell.  We also identified an intrinsic instability in this mechanism of growth that, when combined with natural selection for fast cell growth, led to a global (species-wide) constraint on cell shape.  Second, we found that the bacterial cell wall exhibits (anisotropic) stress-stiffening and stress-softening under under different ranges of mechanical stress, and that these exotic mechanical properties impart cell shape homeostasis when coupled to the simple, empirical dependence of cellular pressure on cell size.