The unusual morphology and poorly defined acrosome-like structure in the mature sperm of the giant freshwater prawn Macrobrachium rosenbergii has led to difficulties in identifying the state of sperm activation. Mature distal vas deferens sperm (dVSp) can be activated by the calcium ionophore A23187 to show acrosome reaction-like enzymatic activities that increase their binding and penetration capabilities. However, these short-lived enzymatic activities limit their usefulness as a marker of sperm activation for further qualitative and quantitative analyses, leading to our examining the alterations in the exposure of sperm surface glycoconjugates both as markers of sperm activation and for their role in gamete interaction. Our results showed that after A23187 treatment, there was an increased exposure of mannosylated glycoconjugates on the sperm surface revealed by significant Concanavalin A (Con A) staining. Furthermore, sodium metaperiodate pre-treatment, Con A pre-incubation, or co-incubation with α-mannose monosaccharides all significantly reduced A23187-induced dVSp binding to the egg vitelline envelop, demonstrating the importance of sperm surface mannosylated glycoconjugates in the binding process. These same pre-treatments of sperm also resulted in the inhibition of the binding of soluble vitelline envelop proteins (MrVE) to both the sperm surface and to mannosylated dVSp protein bands. Therefore, the present study demonstrated the importance of the exposure of mannosylated glycoconjugates on the surface of activated dVSp, both as a reliable marker of sperm activation and as a binding factor in the gamete interaction process. Furthermore, these findings allow for a better understanding of the surface glycoconjugate-mediated interaction process between gametes in this species of prawn.

中文翻译：

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巨型淡水虾中活化精子表面的甘露糖基化糖合物对于精子与卵黄包膜的结合至关重要

巨型淡水虾罗氏沼虾成熟精子中不寻常的形态和不明确的顶体样结构导致难以确定精子的激活状态。成熟的远端输精管精子 (dVSp) 可以被钙离子载体 A23187 激活，以显示出类似顶体反应的酶活性，从而增加它们的结合和渗透能力。然而，这些短暂的酶活性限制了它们作为精子激活标志物进行进一步定性和定量分析的有用性，导致我们检查精子表面糖缀合物暴露的变化，作为精子激活的标志物和它们在配子相互作用中的作用. 我们的结果表明，经过 A23187 处理后，明显的伴刀豆球蛋白 A (Con A) 染色显示精子表面甘露糖化糖缀合物的暴露增加。此外，偏高碘酸钠预处理、Con A 预孵育或与 α-甘露糖单糖共孵育均显着降低了 A23187 诱导的 dVSp 与卵黄膜的结合，证明了精子表面甘露糖化糖缀合物在结合过程中的重要性。这些相同的精子预处理也导致可溶性卵黄包膜蛋白 (MrVE) 与精子表面和甘露糖化 dVSp 蛋白带的结合受到抑制。因此，本研究证明了在活化的 dVSp 表面暴露甘露糖基化糖缀合物的重要性，既是精子激活的可靠标志，也是配子相互作用过程中的结合因子。此外，这些发现有助于更好地了解这种对虾配子之间表面糖轭介导的相互作用过程。