Petit H, Davis W L, Jones R G, Hagler H K
Tissue Cell. 1980;12(1):13-28. doi: 10.1016/0040-8166(80)90049-x.
Light microscopy, transmission electron microscopy, scanning electron microscopy, various histochemical procedures for the localization of mineral ions, and analytical electron microscopy have been used to investigate the mechanisms inherent at the mantle edge for shell formation and growth in Amblema plicata perplicata, Conrad. The multilayered periostracum, its component laminae formed from the epithelia lining either the periostracal groove or the outer mantle epithelium (of the periostracal cul de sac), appears to play the major regulatory and organizational role in the formation of the component mineralized layers of the shell. Thus, the inner layer of the periostracum traps and binds calcium and subsequently gives rise to matricial proteinaceous fibrils or lamellar extensions which serve as nucleation templates for the formation and orientation of the crystalline subunits (rhombs) in the forming nacreous layer. Simultaneously, the middle periostracal layer furnishes or provides the total ionic calcium pool and the matrical organization necessary for the production of the spherical subunits which pack the matrical 'bags' of the developing prismatic layer. The outer periostracal layer appears to be a supportive structure, possibly responsible for the mechanical deformations which occur in the other laminae of the periostracum. The functional differences in the various layers of the periostracum are related to peculiar morphological variables (foliations, vacuolizations, columns) inherent in the structure and course of this heterogeneous (morphologically and biochemically) unit. From this study, using the dynamic mantle edge as a morphological model system, we have been able to identify at least six interrelated events which culminate in the production of the mature mineralized shell layers (nacre, prisms) at the growing edge of this fresh-water mussel.
利用光学显微镜、透射电子显微镜、扫描电子显微镜、多种用于定位矿质离子的组织化学方法以及分析电子显微镜，对Amblema plicata perplicata（康拉德）贝壳形成和生长的外套膜边缘内在机制进行了研究。多层角质层，其组成薄片由角质层沟或角质层盲囊的外套膜外上皮衬里形成，似乎在贝壳矿化组成层的形成中起主要调节和组织作用。因此，角质层的内层捕获并结合钙，随后产生基质蛋白纤维或层状延伸物，这些纤维或延伸物作为形成珍珠质层中晶体亚基（菱形）的成核模板。同时，中间角质层提供形成棱柱层的球形亚基所需的全部离子钙库和基质组织，这些球形亚基填充发育中棱柱层的基质“袋”。角质层外层似乎是一个支撑结构，可能负责角质层其他薄片中发生的机械变形。角质层各层的功能差异与这个异质（形态和生化方面）单元的结构和进程中固有的特殊形态变量（叶状、空泡化、柱状）有关。通过这项研究，以动态的外套膜边缘作为形态学模型系统，我们已经能够识别至少六个相互关联的事件，这些事件最终导致在这种淡水贻贝生长边缘产生成熟的矿化壳层（珍珠质、棱柱）。
