Phage display is a widely used technique for selecting specific binding peptides, but presenting antigens in their natural form can be challenging, as protein coating may induce structural changes. In this study, we employed a whole cell-based phage display technique without a coating step to select peptides that bind specifically to Daphnia magna eggs. Boiled eggs were used as a control to ensure that antigens were presented in their natural forms. We identified a peptide, DEP1 (LYALPLSHLKSHGGG), with the highest binding affinity to D. magna eggs. DEP1 did not affect zebrafish eggs, but it inhibited normal hatching and reproductive ability in D. magna eggs, and hindered growth in neonates before their first ecdysis. Morphological analysis revealed that DEP1 caused intestinal damage and tissue abnormalities. Our findings demonstrate that the whole cell-based phage display technique is successful in presenting antigens in their natural form, and that the DEP1 peptide can be applied to regulate the growth cycle of D. magna. These results have implications for the use of phage display in environmental research and the potential use of DEP1 for hazardous organisms in aquatic systems.

噬菌体展示是一种广泛使用的技术，用于选择特异性结合肽，但以其天然形式呈递抗原可能具有挑战性，因为蛋白质涂层可能会引起结构变化。在这项研究中，我们采用了一种无需包被步骤的全细胞噬菌体展示技术来选择与大型蚤卵特异性结合的肽。煮鸡蛋用作对照以确保抗原以其天然形式呈现。我们鉴定了一种肽 DEP1 (LYALPLSHLKSHGGG)，它对D. magna卵具有最高的结合亲和力。DEP1 不影响斑马鱼卵，但会抑制D. magna的正常孵化和繁殖能力卵，并阻碍新生儿在第一次蜕皮前的生长。形态学分析显示 DEP1 引起肠道损伤和组织异常。我们的研究结果表明，基于全细胞的噬菌体展示技术成功地以其天然形式呈递抗原，并且 DEP1 肽可用于调节D. magna的生长周期。这些结果对环境研究中噬菌体展示的使用以及 DEP1 对水生系统中有害生物的潜在用途具有影响。