Abstract：
Endolysins have garnered significant attention as a potential alternative to antibiotics in aquaculture, mainly for combating Vibrio spp., Gram-negative pathogens responsible for infectious outbreaks. However, endolysin effectiveness against Gram-negative bacteria is limited due to the outer membrane\'s poor permeability. The combat against marine pathogens poses an additional challenge of finding endolysins that retain their activity in high ionic strength conditions. Thus, this study aimed to demonstrate that certain endolysins retain muralytic activity in seawater and also evaluated outer membrane permeabilizers as endolysin adjuvants. The effectiveness of KZ144 and LysPA26 endolysins, along with EDTA and oregano essential oil, was evaluated against Vibrio parahaemolyticus ATCC-17802 in natural seawater. Results revealed the muralytic activity of both endolysins in seawater. However, the endolysins appeared to counteract the permeabilizers\' effect during the initial bactericidal assays. Further investigations revealed that the observed effect was not antagonistic. After the permeabilizer action, V. parahaemolyticus likely used endolysins as a growth substrate. Endolysins may not play an indifferent role if they fail to exert a bactericidal effect. Instead, they can serve as a substrate for fast-growing bacteria, such as V. parahaemolyticus, increasing bacterial density. It should be considered a potential drawback of endolysins\' proteinaceous nature as bactericidal agents.
摘要：
Endolysin作为水产养殖中抗生素的潜在替代品已经引起了人们的广泛关注。主要用于对抗弧菌。,引起传染病暴发的革兰氏阴性病原体。然而,内溶素对革兰氏阴性菌的有效性是有限的，因为外膜的渗透性差。对抗海洋病原体的斗争提出了寻找在高离子强度条件下保持其活性的内溶素的额外挑战。因此，这项研究旨在证明某些内溶素在海水中保留了杀菌作用，并评估了外膜透化剂作为内溶素佐剂。KZ144和LysPA26内溶素的有效性，还有EDTA和牛至精油,对天然海水中的副溶血性弧菌ATCC-17802进行了评估。结果揭示了两种内溶素在海水中的杀虫活性。然而,在最初的杀菌试验中，内溶素似乎抵消了透化剂的作用。进一步的研究表明，观察到的效果不是拮抗作用。渗透作用后，副溶血病毒可能使用内溶素作为生长底物。如果内皮素不能发挥杀菌作用，它们可能不会发挥无关紧要的作用。相反，它们可以作为快速生长的细菌的底物，例如副溶血性弧菌，增加细菌密度。应将其视为内溶素作为杀菌剂的蛋白质性质的潜在缺点。
