Lo W K, Harding C V
J Ultrastruct Res. 1984 Mar;86(3):228-45. doi: 10.1016/s0022-5320(84)90103-5.
Square arrays in human lens fibers were studied with freeze-fracture and thin-section TEM. In superficial fibers a number of patches of square array particles in the P face and pits in the E face are found in the smooth membrane. In the deeper cortex and the nucleus, fiber cells have undulating membranes and many ridges. Numerous patches of the particles (P face) are distributed in the concave regions, and the pits (E face) in the convex areas of the bumpy membrane. In most ridges, patches of the particles occur at regular intervals in the "valley" portion, while the pits are on the "crest" portion of ridges. Also, continuous square arrays having the same "valley" location as the regularly arranged patches are found in areas with extensive ridge patterns. The overlapping of the outer portions of two adjacent square arrays is found on the sides between the "crest" and the "valley" of the ridges. Structurally, square arrays are located in a nonjunctional part of the membrane; in an orthogonal crystalline arrangement; and with a particle size of about 6 nm and center-center spacing about 6.4 nm. They are structurally different from gap junctions found in the lens fibers. Thin-section studies reveal two types of cellular contacts: thin pentalamellar structures (about 12-13 nm in overall thickness) associated with the ridge patterns are believed to be square arrays; thick heptalamellar structures (about 16-17 nm in overall thickness) with a narrow gap in between the two central laminae are believed to be gap junctions. This study strongly suggests that square arrays are specifically involved in ridge formation in human lens fibers.
利用冷冻断裂和超薄切片透射电子显微镜对人晶状体纤维中的方形阵列进行了研究。在表层纤维中，在平滑膜的P面上发现了一些方形阵列颗粒斑块，在E面上发现了凹坑。在更深的皮质和核中，纤维细胞具有起伏的膜和许多嵴。大量颗粒斑块（P面）分布在凹凸不平膜的凹陷区域，凹坑（E面）分布在凸起区域。在大多数嵴中，颗粒斑块在“谷”部以规则间隔出现，而凹坑在嵴的“峰”部。此外，在具有广泛嵴模式的区域中发现了与规则排列的斑块具有相同“谷”位置的连续方形阵列。在嵴的“峰”和“谷”之间的侧面发现了两个相邻方形阵列外部的重叠。从结构上看，方形阵列位于膜的非连接部分；呈正交晶体排列；颗粒大小约为6nm，中心间距约为6.4nm。它们在结构上与晶状体纤维中的间隙连接不同。超薄切片研究揭示了两种细胞接触类型：与嵴模式相关的薄五片层结构（总厚度约12 - 13nm）被认为是方形阵列；厚七片层结构（总厚度约16 - 17nm），两个中央片层之间有狭窄间隙，被认为是间隙连接。这项研究有力地表明，方形阵列特别参与了人晶状体纤维中嵴的形成。
