Candidate Lecture - Dr. Dvir Gur, HHMI, Janelia Research Campus USA

Date: 

Thu, 26/11/2020 - 09:00 to 10:00

Location: 

https://huji.zoom.us/j/82970786574?pwd=ZTByU3g5bVRJS05DYWNxNS9qeFpDQT09

From colors tokidney stones: The cellular control of organic-crystal forming cells


Abstract:

Chameleons, spiders, planktonic crustaceans, fish, and many other animals use organic crystals for an
astonishing variety of optical functions, from white light scattering in spiders to tunable reflecting colors in
the copepods. These crystals are formed by specialized cells called iridophores, in which remarkable
control over crystal shape, size, and assembly is obtained using strategies that are beyond state of the art
in materials science and solid-state chemistry. While these cells were identified many years ago, almost
nothing is known about the biophysical and biochemical processes which enable this tremendous control
over bio-organic crystals.

We used the zebrafish skin iridophores as a model system to investigate: 1. How cells with different
architectures and different optical properties are obtained, and 2. What is the cellular machinery which
drives structural color change?

Using diverse tools, we found that distinct iridophore types with different crystal morphologies,
architectures, and optical properties were obtained by differentiation based on their microenvironments.
We further found that only one type of iridophores was capable of changing its colors and that this color
change was facilitated by motor proteins actively pulling the membrane-bound crystals.