摘要

       大鲵长期以来被誉为中药。它的血液被认为是肉类生产工业的废物或副产品。虽然目前已有不同来源抗菌肽的分离报道，但还没有从大卫王血中分离到抗菌肽的报道。本文采用磁性脂质体吸附和反相高效液相色谱相结合的方法，从大卫矛血中分离出一种抗菌肽蓖麻毒素B。进一步研究了两性霉素B的结构、抗菌活性和安全性。氨基酸序列经N末端测序确定为Gly-Leu-Thr-Arg-Leu-Phe-Ser-Val Ile Lys。圆二色性（CD）光谱和生物信息学软件对三维结构的预测表明存在一个明确的随机线圈构象。蓖麻毒素B对本研究所检测的所有细菌和一些真菌都有活性。最低抑菌浓度（MICs）为8-64μg ml-1。此外，溶血试验也表明，二恶英B在MICs中是安全的。最后，蓖麻毒素B抑制了大鲵熟肉中金黄色葡萄球菌的生长。本研究表明，两性霉素B是一种很有前途的新型抗菌肽，有望为新药开发提供新的思路。
        研究的意义和影响：
        这是首次从大鲵血液中筛选和分离抗菌肽的研究。本文采用磁性脂质体吸附与反相高效液相色谱相结合的方法，对抗菌肽进行分离纯化和筛选。从这一筛选中，我们发现了一种新的抗菌肽，我们称之为两性霉素B。两性霉素B是唯一的，因为它既检查了革兰氏阳性菌和革兰氏阴性菌的生长，也检查了少数真菌种类。

The Andrias davidianus has been known as a traditional Chinese medicine for a long time. Its blood is considered as a waste or by-product of the meat production industry. Although there are reports on isolation of the antimicrobial peptides from different resources, there are no reports of their isolation from A. davidianus blood. In this work, an antimicrobial peptide, andricin B, was isolated from the blood of A. davidianus by an innovative method in which the magnetic liposome adsorption was combined with reversed-phase high-performance liquid chromatography. The structure, antimicrobial activity and safety of andricin B were further investigated. Amino acid sequence was determined by N-terminal sequencing and found to be Gly-Leu-Thr-Arg-Leu-Phe-Ser-Val-Ile-Lys. Circular dichroism (CD) spectra and prediction of three-dimensional structure by bioinformatics software suggested the presence of a well-defined random coil conformation. Andricin B was found to be active against all bacteria tested in this study as well as some fungi. The minimum inhibitory concentrations (MICs) were in the range 8-64 μg ml^-1 . Moreover, the haemolytic testing also suggested that andricin B could be considered safe at the MICs. Finally, andricin B was shown to inhibit the growth of Staphylococcus aureus in the cooked meat of A. davidianus. This study shows that andricin B is a promising novel antimicrobial peptide that may provide further insights towards the development of new drugs.

SIGNIFICANCE AND IMPACT OF THE STUDY:

This is the pioneer study on screening and isolation of antimicrobial peptide from the blood of Andrias davidianus. Here, we have developed a novel method by combining magnetic liposomes adsorption with reversed-phase high-performance liquid chromatography to purify and screen the antimicrobial peptides. From this screen, we identified a novel antimicrobial peptide which we name as andricin B. Andricin B is unique as it checks the growth of both Gram-positive and Gram-negative bacteria as well as few fungal species.

         https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/lam.12823