Cathelicidins are a class of antimicrobial peptides (AMPs) known to possess rapid and direct antimicrobial activities against a variety of microorganisms. Recently identified cathelicidins derived from alligator and sea snake were found to be more effective in inhibiting microbial growth than other AMPs previously characterized. The ability of these two cathelicidins along with the peptides, cecropin and pleurocidin, to protect channel catfish (Ictalurus punctatus, Rafinesque) and hybrid catfish (I. punctatus ♀ × blue catfish, Ictalurus furcatus, Valenciennes ♂) against Edwardsiella ictaluri, one of the most prevalent pathogens affecting commercial catfish industry, was investigated. Cathelicidin‐injected fish (50 µg ml⁻¹ fish⁻¹) that were simultaneously challenged with E. ictaluri through bath immersion at a concentration of ~1 × 10⁶ CFU/ml had increased survival rates compared with other peptide treatments and the infected control. Bacterial numbers were also reduced in the liver and kidney of channel catfish and hybrid catfish in the cathelicidin treatments 24 hr post‐infection. After 8 days of challenge, serum was collected to determine immune‐related parameters such as bactericidal activity, lysozyme, serum protein, albumin and globulin. These immune‐related parameters were significantly elevated in fish injected with the two cathelicidins as compared to other peptide treatments. These results indicate that cathelicidins derived from alligator and sea snake can stimulate immunity and enhance the resistance to E. ictaluri infection in channel catfish and hybrid catfish.

中文翻译：

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鞘磷脂可增强对cat鱼，斑点叉尾and和channel蓝色fur鱼，furcatus♂杂交♂的保护，以防止埃德瓦尔西氏菌感染。

鞘磷脂是一类抗菌肽（AMP），已知具有针对多种微生物的快速直接抗菌活性。发现最近鉴定出的来自短吻鳄和海蛇的cathelicidins比以前表征的其他AMP在抑制微生物生长方面更有效。与肽，天蚕素沿着这两个导管素的能力和pleurocidin，以保护斑点叉尾鮰（斑点叉尾鮰，Rafinesque）和混合鲶鱼（I.毛虫♀×蓝色鲶鱼，斑点叉尾furcatus，瓦朗谢讷♂反对）爱德华氏菌是影响商业cat鱼产业的最普遍的病原体之一。注射了Cathelicidin的鱼（50 µg ml ^-1 鱼^-1）通过浸浴以约1×10 ⁶的浓度同时受到肠埃希氏菌的攻击与其他肽治疗和感染的对照组相比，CFU / ml具有更高的存活率。在感染后24小时进行的cathelicidin处理中，channel鱼和杂种cat鱼的肝脏和肾脏中的细菌数量也减少了。攻击8天后，收集血清以确定免疫相关参数，例如杀菌活性，溶菌酶，血清蛋白，白蛋白和球蛋白。与其他肽处理相比，注射了两种Cathelicidins的鱼的这些免疫相关参数显着升高。这些结果表明，源自短吻鳄和海蛇的Cathelicidins可以刺激免疫性并增强对channel鱼和杂种cat鱼的埃卡塔里氏菌感染的抵抗力。