Ding Yifeng, Zhang Yu, Huang Chenxi, Wang Jia, Wang Xiaohong
Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Wuhan 430070, China.
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Microorganisms. 2020 May 15;8(5):737. doi: 10.3390/microorganisms8050737.
is responsible for a wide range of infections and is a constant threat to public health, particularly in light of emerging antibiotic resistance. The use of bacteriophages and phage endolysins as specific antibacterial agents is a promising strategy to control this bacterial infection. Endolysins are important proteins during the process of bacteria lysis by bacteriophages. In this study, we identify a novel endolysin, named LysSE24. LysSE24 was predicted to possess -acetylmuramidases activity, with a molecular mass of ca. 17.4 kDa and pI 9.44. His-tagged LysSE24 was heterologously expressed and purified by Ni-NTA chromatography. LysSE24 exhibited optimal bactericidal activity against Enteritidis ATCC 13076 at a concentration of 0.1 μM. population (measured by OD) decreased significantly ( < 0.05) after 10 min of incubation in combination with the outer membrane permeabilizer in vitro. It also showed antibacterial activity against a panel of 23 tested multidrug-resistant strains. Bactericidal activity of LysSE24 was evaluated in terms of pH, temperature, and ionic strength. It was very stable with different pH (4.0 to 10.0) at different temperatures (20 to 60 °C). Both K and Na at concentrations between 0.1 to 100 mM showed no effects on its bactericidal activity, while a high concentration of Ca and Mg showed efficacy. Transmission electron microscopy revealed that exposure to 0.1 μM LysSE24 for up to 5 min caused a remarkable modification of the cell shape of Enteritidis ATCC 13076. These results indicate that recombinant LysSE24 represents a promising antimicrobial activity against , especially several multidrug-resistant strains. Further studies can be developed to improve its bactericidal activity without the need for pretreatment with outer membrane-destabilizing agents by synthetic biology methods.
[病原体名称]引发多种感染，始终威胁着公众健康，尤其是鉴于新出现的抗生素耐药性。使用噬菌体和噬菌体溶菌酶作为特异性抗菌剂是控制这种细菌感染的一种有前景的策略。溶菌酶是噬菌体裂解细菌过程中的重要蛋白质。在本研究中，我们鉴定出一种新型溶菌酶，命名为LysSE24。预测LysSE24具有N - 乙酰胞壁酸酶活性，分子量约为17.4 kDa，等电点为9.44。His标签的LysSE24通过镍 - 氮三乙酸（Ni - NTA）色谱法进行异源表达和纯化。LysSE24在浓度为0.1 μM时对肠炎沙门氏菌ATCC 13076表现出最佳杀菌活性。在体外与外膜通透剂共同孵育10分钟后，菌液浓度（通过OD测量）显著下降（P < 0.05）。它还对一组23种测试的多重耐药菌株表现出抗菌活性。从pH、温度和离子强度方面评估了LysSE24的杀菌活性。在不同温度（20至60 °C）下，它在不同pH（4.0至10.0）条件下都非常稳定。浓度在0.1至100 mM之间的钾离子和钠离子对其杀菌活性均无影响，而高浓度的钙离子和镁离子显示出效果。透射电子显微镜显示，暴露于0.1 μM LysSE24长达5分钟会导致肠炎沙门氏菌ATCC 13076的细胞形态发生显著改变。这些结果表明，重组LysSE24对[病原体名称]具有有前景的抗菌活性，尤其是对几种多重耐药菌株。可以通过合成生物学方法开展进一步研究，以在无需用外膜去稳定剂预处理的情况下提高其杀菌活性。
