Microvillar orientation in the photoreceptors of the ant Cataglyphis bicolor
Microvillar orientation in the photoreceptors of the ant Cataglyphis bicolor
复制标题
双色蚂蚁光感受器中的微绒毛方向
DOI：
10.1007/s004410051242
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发表时间：
1999
影响因子：
3.6
通讯作者：
V. Domanico
中科院分区：
文献类型：
--
作者：
E. Meyer;V. Domanico
节肢动物光感受器的偏振敏感性主要取决于微绒毛在感杆体内的排列。在这里，我们提出了一个电子显微镜的研究中，微绒毛排列的程度和变化的横截面积的横纹肌沿着他们的长度进行了研究，在沙漠蚂蚁，Cataglyphis bicolor. Series的横截面通过视网膜进行了研究，并确定了方向的微绒毛的光感受器的单独识别小眼。在Cataglyphis复眼的三个解剖和功能上不同的区域：背缘区（dorsal rim area，RRA）、背侧区（dorsal area，DA）和腹侧区（ventral area，VA）进行了微绒毛排列的重建。以下形态学发现与先前通过细胞内记录测量的偏振灵敏度一致。(1)光感受器的微绒毛沿着细胞的整个长度平行排列，从杆束的远端到近端，靠近基底膜。小网膜细胞R1和R5的微绒毛总是彼此平行，并且与其余受体细胞的微绒毛方向完全垂直，只有微小的偏差。(2)在眼睛的DA和VA区域，小受体R1、R3、R5、R7和R9的微绒毛簇每隔1-4 μm重复改变方向，最多可达90°。相反，大的受体细胞R2、R4、R6和R8严格地保持它们的微绒毛取向。(3)在小眼内，横纹肌的横截面积沿横纹肌的长度沿着不发生变化，但在DA和VA小眼内发生实质性变化。
Polarization sensitivity in arthropod photoreceptors is crucially dependent on the arrangement of the microvilli within the rhabdom. Here, we present an electron-microscopical study in which the degree of microvillar alignment and changes in the cross-sectional areas of the rhabdoms along their length were studied in the compound eye of the desert ant,Cataglyphis bicolor.Serial cross-sections through the retina were taken and the orientation of the microvilli was determined in the photoreceptors of individually identified ommatidia. The reconstructions of microvillar alignment were made in the three anatomically and functionally distinct regions of theCataglyphiscompound eye: the dorsal rim area (DRA), the dorsal area (DA), and the ventral area (VA). The following morphological findings are consistent with polarization sensitivities measured previously by intracellular recordings. (1) The microvilli of the DRA photoreceptors are aligned in parallel along the entire length of the cell from the distal tip of the rhabdom down to its proximal end, near the basement membrane. The microvilli of the retinular cells R1 and R5 are always parallel to each other and perfectly perpendicular, with only minor deviation, to the microvillar orientation of the remaining receptor cells. (2) In the DA and VA regions of the eye, the microvillar tufts of the small receptors R1, R3, R5, R7, and R9 change their direction repetitively every 1–4 μm for up to 90°. In contrast, the large receptor cells R2, R4, R6, and R8 maintain their microvillar orientation rigidly. (3) In the DRA ommatidia, the cross-sectional areas of the rhabdomeres do not change along the length of the rhabdom, but substantial changes occur in the DA and VA ommatidia.