Retamal C, Urzúa J, Lorca C, López M L, Alves E W
Faculty of Medicine, University of Chile, Santiago.
J Submicrosc Cytol Pathol. 2000 Apr;32(2):229-39.
The present paper reports modifications in the electrophoretic and cytochemical characteristics of mature and immature stallion spermatozoa. Some sperm surface glycoproteins (36, 32, 29, 21, 20, 18 kDa) detected in cauda epididymidis spermatozoa, were either absent or present in a very low relative concentration in immature sperm cells. A major 14 kDa protein band, observed in sperm extracts obtained from ductus efferentes, progressively decreased along the epididymal ductus. The nature and distribution of carbohydrate residues on the sperm membrane, during epididymal maturation, was also studied by use of lectin probes. Some protein bands bound concanavalin A while others, as the 36, 32 and 20 kDa proteins, exhibited higher affinity for WGA lectin. The distribution and relative density of mannose-, galactose-, N-acetylglucosamine-, N-acetylgalactosamine-, fucose- and sialic acid-containing macromolecules showed a characteristic pattern depending on the sperm membrane domain and on its origin. Some sperm surface domains displayed affinity for more than one lectin, indicating a diversity in their exposed carbohydrate residues, whereas others bound only one or no lectin. The passage of spermatozoa through the epididymidis was accompanied by changes in the accessibility or abundance of lectin ligands. Some lectins (UEA, WGA, LPA) gave stronger reaction in mature spermatozoa, while others (RCA, WFH, PNA) stained better immature spermatozoa. This remodeling of sperm surface molecules is probably a consequence of interactions between spermatozoa and the epididymal secretions, and may reflect addition or adsorption of new molecules, space configurations changes or biochemical modifications of pre-existing compounds. Our results suggest that the distribution and density of terminal oligosaccharidic residues on the sperm plasma membrane have species-specific characteristics. These post testicular developmental changes may be of significance in the overall understanding of the stallion fertility.
本文报道了成熟和未成熟种马精子电泳和细胞化学特性的变化。在附睾尾精子中检测到的一些精子表面糖蛋白（36、32、29、21、20、18 kDa），在未成熟精子细胞中要么不存在，要么相对浓度非常低。在输出小管获得的精子提取物中观察到的一条主要的14 kDa蛋白带，沿着附睾管逐渐减少。还利用凝集素探针研究了附睾成熟过程中精子膜上碳水化合物残基的性质和分布。一些蛋白带与伴刀豆球蛋白A结合，而其他一些，如36、32和20 kDa蛋白，则对WGA凝集素表现出更高的亲和力。含甘露糖、半乳糖、N-乙酰葡糖胺、N-乙酰半乳糖胺、岩藻糖和唾液酸的大分子的分布和相对密度显示出一种特征模式，这取决于精子膜结构域及其来源。一些精子表面结构域对不止一种凝集素表现出亲和力，表明其暴露的碳水化合物残基具有多样性，而其他一些则只结合一种凝集素或不结合凝集素。精子通过附睾的过程伴随着凝集素配体可及性或丰度的变化。一些凝集素（UEA、WGA、LPA）在成熟精子中反应更强，而其他一些（RCA、WFH、PNA）对未成熟精子染色更好。精子表面分子的这种重塑可能是精子与附睾分泌物相互作用的结果，可能反映了新分子的添加或吸附、空间构型的变化或现有化合物的生化修饰。我们的结果表明，精子质膜上末端寡糖残基的分布和密度具有物种特异性特征。这些睾丸后发育变化可能对全面理解种马的生育能力具有重要意义。
