Unité Biologie des organismes et écosystèmes aquatiques (BOREA), Muséum national d'Histoire naturelle, UMR CNRS 7208, Université de Caen Normandie, Sorbonne Université, IRD 207, Université des Antilles, 75005 Paris, France.
Laboratoire Matière et Systèmes Complexes (MSC), Université Paris Diderot, UMR CNRS 7057, 75205 Paris Cedex 13, France.
J R Soc Interface. 2019 Sep 27;16(158):20190175. doi: 10.1098/rsif.2019.0175. Epub 2019 Sep 4.
The cuttlefish shell is an internal structure with a composition and general organization unique among molluscs. Its formation and the structure-function relation are explored during Sepia officinalis development, using computerized axial tomography scanning (CAT-scan) three-dimensional analyses coupled to physical measurements and modelling. In addition to the evolution of the overall form, modifications of the internal structure were identified from the last third embryonic stages to adult. Most of these changes can be correlated to life cycle stages and environmental constraints. Protected by the capsule during embryonic life, the first internal chambers are sustained by isolated pillars formed from the dorsal to the ventral septum. After hatching, the formation of pillars appears to be a progressive process from isolated points to interconnected pillars forming a wall-delineated labyrinthine structure. We analysed the interpillar space, the connectivity and the tortuosity of the labyrinth. The labyrinthine pillar network is complete just prior to the wintering migration, probably to sustain the need to adapt to high pressure and to allow buoyancy regulation. At that time, the connectivity in the pillar network is compensated by an increase in tortuosity, most probably to reduce liquid diffusion in the shell. Altogether these results suggest adjustment of internal calcified structure development to both external forces and physiological needs.
乌贼的内壳是一种内部结构，其组成和总体组织在软体动物中是独特的。利用计算机轴向断层扫描（CAT 扫描）三维分析与物理测量和建模相结合，对乌贼内壳的形成及其结构-功能关系进行了研究。除了整体形态的进化，从胚胎发育的最后三分之一阶段到成年期，还确定了内部结构的变化。这些变化中的大部分可以与生命周期阶段和环境限制相关联。在胚胎期，内壳受到胶囊的保护，最初的几个内部腔室由从背至腹的隔片上的孤立支柱支撑。孵化后，支柱的形成似乎是一个从孤立点到相互连接的支柱形成壁界定的迷宫状结构的渐进过程。我们对内支柱之间的空间、连通性和迷宫的曲折度进行了分析。在冬季洄游之前，迷宫状的支柱网络已经完全形成，可能是为了适应高压并允许浮力调节的需要。此时，通过增加曲折度来补偿支柱网络中的连通性，这很可能是为了减少壳内液体的扩散。总的来说，这些结果表明内部钙化结构的发育是为了适应外部力量和生理需求而进行调整的。
