Gur Dvir, Nicolas Jan-David, Brumfeld Vlad, Bar-Elli Omri, Oron Dan, Levkowitz Gil
Department of Physics of Complex Systems Weizmann Institute of Science Rehovot 7610001 Israel.
Department of Molecular Cell Biology Weizmann Institute of Science Rehovot 7610001 Israel.
Adv Sci (Weinh). 2018 Jun 6;5(8):1800338. doi: 10.1002/advs.201800338. eCollection 2018 Aug.
Many marine organisms have evolved a reflective iris to prevent unfocused light from reaching the retina. The fish iris has a dual function, both to camouflage the eye and serving as a light barrier. Yet, the physical mechanism that enables this dual functionality and the benefits of using a reflective iris have remained unclear. Using synchrotron microfocused diffraction, cryo-scanning electron microscopy imaging, and optical analyses on zebrafish at different stages of development, it is shown that the complex optical response of the iris is facilitated by the development of high-order organization of multilayered guanine-based crystal reflectors and pigments. It is further demonstrated how the efficient light reflector is established during development to allow the optical functionality of the eye, already at early developmental stages.
许多海洋生物进化出了反射性虹膜，以防止未聚焦的光线到达视网膜。鱼类虹膜具有双重功能，既能伪装眼睛，又能作为光屏障。然而，实现这种双重功能的物理机制以及使用反射性虹膜的好处仍不明确。通过对不同发育阶段的斑马鱼进行同步加速器微聚焦衍射、低温扫描电子显微镜成像和光学分析，研究表明，多层鸟嘌呤基晶体反射器和色素的高阶组织发育促进了虹膜复杂的光学响应。进一步证明了高效光反射器在发育过程中是如何形成的，从而使眼睛在早期发育阶段就具备光学功能。
