Roy Debarun, Dey Souvik, Majumder Gopal Chandra, Bhattacharyya Debdas
Centre for Rural and Cryogenic Technologies, Jadavpur University, FT & BE Building, Kolkata, 700032, India.
Glycoconj J. 2014 May;31(4):281-8. doi: 10.1007/s10719-014-9524-z. Epub 2014 Apr 22.
Effects of several bivalent metal ions on the autoagglutination event in mature caprine epididymal sperm cells have been investigated using a chemically defined medium. This study demonstrates for the first time that Copper (Cu(2+)) ion (300 μM) has high specificity for autoagglutination of mature cauda-epididymal sperm. Head-to-head interaction of the male gametes is responsible for this event. Studies on the effect of various sugars reveal that the autoagglutinated cells can be dissociated specifically with neutralized sialic acid (50 mM), which also inhibits the sperm cell autoagglutination phenomenon. Blood serum protein fetuin, that contains terminal sialic acid residue, showed high efficacy for inhibiting this autoagglutination event at 4 μM concentration. However, asialofetuin is not capable of inhibiting this Cu(2+)-dependent cellular event. Mature sperm cells bound with caprine erythrocytes at their head region in presence of Cu(2+) ion. The purified sperm membrane fraction isolated by aqueous two phase polymer method showed high efficacy to agglutinate erythrocytes. These sperm-erythrocyte interactions as well as sperm membrane induced haemagglutination were strongly blocked by neutralized sialic acid (50 mM). The results confirm the occurrence of unique Cu(2+) dependent, sialic acid-specific lectin on the outer surface of a mammalian cell using caprine sperm as the model. The observed Cu(2+)-mediated cellular autoagglutination is caused by the interaction of the cell surface lectin with the lectin receptor on the surface of the neighboring homologous cell.
使用化学成分明确的培养基，研究了几种二价金属离子对成熟山羊附睾精子细胞自凝集事件的影响。本研究首次证明，铜（Cu(2+)）离子（300 μM）对成熟附睾尾精子的自凝集具有高度特异性。雄配子的头对头相互作用导致了这一事件。对各种糖类作用的研究表明，自凝集细胞可以被中和的唾液酸（50 mM）特异性解离，唾液酸也能抑制精子细胞自凝集现象。含有末端唾液酸残基的血清蛋白胎球蛋白在4 μM浓度下对抑制这种自凝集事件显示出高效性。然而，去唾液酸胎球蛋白不能抑制这种依赖铜离子的细胞事件。在铜离子存在的情况下，成熟精子细胞在其头部区域与山羊红细胞结合。通过双水相聚合物法分离得到的纯化精子膜部分对凝集红细胞显示出高效性。这些精子与红细胞的相互作用以及精子膜诱导的血细胞凝集被中和的唾液酸（50 mM）强烈阻断。结果证实，以山羊精子为模型，在哺乳动物细胞外表面存在独特的依赖铜离子、对唾液酸特异的凝集素。观察到的铜离子介导的细胞自凝集是由细胞表面凝集素与相邻同源细胞表面的凝集素受体相互作用引起的。
