Microscopic and biochemical characterization of lectin binding sites in the cephalopod retina.
Microscopic and biochemical characterization of lectin binding sites in the cephalopod retina.
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头足类视网膜凝集素结合位点的显微镜和生化特征。
DOI：
10.1002/cne.902830409
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Robles,LJ
中科院分区：
文献类型：
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作者：
Taba,A;Quezada,BH;Robles,LJ
应用光镜、电子显微镜细胞化学和凝集素印迹技术，我们证明了凝集素刀豆蛋白A(ConA)、蓖麻凝集素(RCA)和花生凝集素(PNA)可与成体头足类视网膜中的特定糖结合。在光镜下，用FITC或TRITC标记的凝集素对乙醛固定的、冷冻的或卤石包埋的头足类动物视网膜的蚀刻切片进行细胞化学处理，并用荧光显微镜进行观察。整个视网膜的ConA标记结构包括内界膜(ILM)、横纹膜、光感受器间基质(IPM)和光感受器内节段的结构。RCA标记与ConA相似，不同之处在于ILM附近的带状尖端的染色减少。PNA仅标记相对横纹肌之间的光感受器间基质。PNA对IPM的染色强度也向纹状尖端减弱或消失。没有一种凝集素标记位于光感受器内段的髓样小体。用金标记的凝集素对醛固定的LR White包埋组织或Araldite包埋的高碘酸盐蚀刻切片进行了电子显微镜凝集素细胞化学研究。EM结果证实了光学显微镜的观察结果。凝集素与视网膜提取物或光敏膜部分的印迹显示出由所有三种凝集素标记的各种蛋白条带。ConA和RCA标记视蛋白及其聚集体，而PNA不标记。用PNA标记的头足类IPM表明脊椎动物和无脊椎动物的IPM结构相似。在其他研究中，我们已经证明了在头足类动物的IPM中存在维甲酸结合蛋白。因此，头足类可以作为进一步研究IPM的结构和功能及其在视网膜维生素A循环中的作用的模型。
Using light and electron microscope cytochemistry and lectin blotting techniques, we have shown that the lectins concanavalin A (Con A),Ricinus communisagglutinin (RCA), and peanut agglutinin (PNA) bind to specific glycoconjugants in the adult cephalopod retina. For light microscope lectin cytochemistry, aldehyde‐fixed, frozen, or Araldite‐embedded, etched sections of cephalopod retinas were incubated with FITC‐ or TRITC‐conjugated lectins and examined by using epifluorescence microscopy. Con A labeled structures in the entire retina including the inner limiting membrane (ILM), rhabdomeric membranes, interphotoreceptor matrix (IPM), and structures in the photoreceptor inner segments. RCA labeling was similar to that of Con A except that there was a decrease in the staining of the rhabdom tips near the ILM. PNA labeled only the interphotoreceptor matrix between apposing rhabdomeres. The intensity of staining of the IPM by PNA also decreased or was absent toward the rhabdom tips. None of the lectins labeled the myeloid bodies located in the photoreceptor inner segments. Electron microscope (EM) lectin cytochemistry was performed on aldehyde‐fixed, LR White–embedded tissue or on Araldite‐embedded, periodate‐etched sections by using gold‐conjugated lectins. EM results confirmed the observations made by light microscopy. Lectin blots with a retinal extract or light‐sensitive membrane fraction revealed a variety of protein bands labeled by all three lectins. Con A and RCA labeled opsin and its aggregates whereas PNA did not. None of the lectins labeled retinochrome.The labeling of the cephalopod IPM by PNA suggests a structural similarity between the IPM of vertebrates and invertebrates. In other studies, we have demonstrated the presence of a retinoid binding protein in the IPM of cephalopods. Thus, cephalopods may serve as a model for further investigations on the structure and function of the IPM and its role in the vitamin A cycle of the retina.