The antibacterial activity and mechanism analysis of piscidin 5 like from Larimichthys crocea
The antibacterial activity and mechanism analysis of piscidin 5 like from Larimichthys crocea
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大黄鱼piscidin 5 like的抗菌活性及机制分析
DOI：
10.1016/j.dci.2018.10.008
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发表时间：
2019-03-01
影响因子：
2.9
通讯作者：
Li, Yuan
中科院分区：
文献类型：
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作者：
Pan, Ying;Zheng, Li-Bing;Li, Yuan
抗生素等化学药物仍是防治水生生物病害的重要物质。然而，抗生素的滥用不仅使其效果甚微，而且还会引起其他不良问题，如细菌耐药性和药物残留。因此，寻找有效的抗生素替代品是一条需要探索的途径。近年来，抗菌肽（Antibacterial Peptides，AMPs）越来越受到人们的关注。刺激隐核虫的寄生和二次入侵是包括大黄鱼在内的几乎所有宿主鱼类的灾难。研究表明，许多抗菌肽在整个寄生虫感染周期中起着关键作用。Piscidin 5 like是Piscidin家族的一员。本研究对鱼腥藻抗菌素5（Lc-P5 L）的抗菌活性及其作用机制进行了研究。液体抑菌试验表明，重组Lc-P5 L（rLc-P5 L）具有广谱抗菌和较强的杀菌活性。杀菌活性以剂量和时间依赖性方式起作用。SEM（扫描电子显微镜）观察到了较为详细的杀菌过程，rLc-P5 L处理后大量细菌堆积在一起，出现大量奇怪的丝状体，并覆盖在细菌表面。此外，金黄色葡萄球菌在细胞膜上生长出大量的颗粒，并在少数细胞膜上形成孔洞，内容物从孔洞中涌出。同时，对抗菌机理进行了探讨。与细菌直接孵育后，Western blot检测到rLc-P5 L在细菌上的明显阳性信号;其次，先与LPS（lipopolysaccharide）或LTA（lipoteichoic acid）孵育后，rLc-P5 L与细菌的再次结合明显受到影响，表明rLc-P5 L可以通过与某些病原体相关分子模式（pathogen-associated molecular patterns，PAMPs）相互作用而与细菌结合。此外，rLc-P5 L可以与细菌基因组DNA相互作用的剂量和时间依赖性的手段。综上所述，rLc-P5 L通过靶向某些PAMPs结合到细菌表面，破坏细胞膜，达到一定的时间和浓度阈值后进入细胞与基因组DNA相互作用，干扰正常代谢，这可能是其发挥抗菌活性的途径。
Chemical drugs, such as antibiotics, were still important materials to prevent and cure diseases of aquatic organisms. However, antibiotics abuse do not only make the effects little, but also cause other bad problems, such as bacterial resistance and drug residues. Therefore, seeking the effective substitutes of antibiotics was an approach needed to be explored. Antibacterial peptides (AMPs) attracted more and more attention in the recent years. The parasitism and secondary bacterial invasion caused by ectroparasite Cryptocaryon irritans was a disaster to almost all host fish, including Larimichthys crocea. Reports indicated many AMPs played a key role in the whole parasitic infection cycle. Piscidin 5 like was a member of piscidin family. In the study, the antibacterial activity and mechanisms of piscidin 5 like from L.coreca (Lc-P5L) were detected. Liquid growth inhibition results showed recombinant Lc-P5L (rLc-P5L) had broad antibacterial spectrum and strong bactericidal activity. The bactericidal activity functioned in dose- and time-dependent manners. SEM (scanning electron microscope) observed the relatively detailed bactericidal process, rLc-P5L treatment resulted in a mass of bacteria piling together, appearing plenty of strange filaments and covering on the bacteria. Besides, S.aureus overgrowed plenty of granules, formed holes on the membrane of a few cells, and contents poured out from the holes. At the same time, antibacterial mechanisms were explored. After direct incubation with bacteria, western blot detected the apparently positive signal of rLc-P5L on bacteria; secondly, the incubation first with LPS (lipopolysaccharide) or LTA (lipoteichoic acid) significantly affect the binding of rLc-P5L to bacteria again, which indicated rLc-P5L could bind to bacteria through interaction with some PAMPs (pathogen-associated molecular patterns). In addition, rLc-P5L could interact with bacterial genome DNA by dose- and time-dependent means. In summary, rLc-P5L binded to bacteria surface through targeting to some PAMPs to damage membrane, and entered into cells to interact with genome DNA to disturb normal metabolism when it reached to some certain time and concentration thresholds, which were likely to be its pathway to exert antibacterial activity.