Abstract：
Mammalian spermatozoa have a surface covered with glycocalyx, consisting of heterogeneous glycoproteins and glycolipids. This complexity arises from diverse monosaccharides, distinct linkages, various isomeric glycans, branching levels, and saccharide sequences. The glycocalyx is synthesized by spermatozoa developing in the testis, and its subsequent alterations during their transit through the epididymis are a critical process for the sperm acquisition of fertilizing ability. In this study, we performed detailed analysis of the glycocalyx on the sperm surface of bull spermatozoa in relation to individual parts of the epididymis using a wide range (24) of lectins with specific carbohydrate binding preferences. Fluorescence analysis of intact sperm isolated from the bull epididymides was complemented by Western blot detection of protein extracts from the sperm plasma membrane fractions. Our experimental results revealed predominant sequential modification of bull sperm glycans with N-acetyllactosamine (LacNAc), followed by subsequent sialylation and fucosylation in a highly specific manner. Additionally, variations in the lectin detection on the sperm surface may indicate the acquisition or release of glycans or glycoproteins. Our study is the first to provide a complex analysis of the bull sperm glycocalyx modification during epididymal maturation.
摘要：
哺乳动物精子的表面覆盖着糖萼，由异质糖蛋白和糖脂组成。这种复杂性源于不同的单糖，不同的联系，各种异构聚糖，分支级别，和糖序列。糖萼是由在睾丸中发育的精子合成的，其在通过附睾运输过程中的后续改变是精子获得受精能力的关键过程。在这项研究中,我们使用广泛的（24种）具有特定碳水化合物结合偏好的凝集素，对公牛精子表面的糖萼与附睾各个部分的关系进行了详细分析。从公牛附睾中分离出的完整精子的荧光分析得到了精子质膜部分蛋白质提取物的Western印迹检测的补充。我们的实验结果揭示了用N-乙酰乳糖胺（LacNAc）对公牛精子聚糖进行主要的序贯修饰，随后以高度特异性的方式进行唾液酸化和岩藻糖基化。此外,精子表面凝集素检测的变化可能表明聚糖或糖蛋白的获取或释放。我们的研究是第一个对附睾成熟过程中的公牛精子糖萼修饰进行复杂分析的研究。
