摘要

细菌素是由某些乳酸菌分泌的核糖体合成的抗菌肽，在食品安全方面的有潜在应用前景。使用包括16S rDNA扩增的生物化学和分子技术鉴定产细菌素的植物乳杆菌LD4，然后测序。 3小时后开始产生细菌素，在早期稳定期达到最大值。存在于无细胞上清液中的细菌素在2.0至6.0的pH范围内以及在不同温度下（15psi压力下60-100和121℃15分钟）显示出稳定性。抗菌活性不受过氧化氢酶，脂肪酶或α-淀粉酶的影响，但在胰蛋白酶和蛋白酶存在下降低，表明该化合物具有蛋白质性质。用不同的有机溶剂，表面活性剂和洗涤剂处理后，活性保持稳定。使用tricine SDS-PAGE发现细菌素LD4的分子量为〜6kDa。对革兰氏阳性菌和革兰氏阴性菌包括藤黄微球菌，金黄色葡萄球菌，大肠杆菌，铜绿假单胞菌，伤寒沙门氏菌，弧菌，阴沟肠杆菌，屎肠球菌以及一些乳酸菌和卤代菌的菌株表现出抗菌活性。细菌素LD4引起靶细胞中的K +离子流出，表明化合物的成孔性质。鉴于各种条件下的稳定性和广泛的抗病原体抗菌谱，细菌素LD4具有应用于食品安全和治疗的潜力。

Bacteriocins are ribosomally synthesized antimicrobial peptides secreted by certain lactic acid bacteria, with potential application in food safety. Bacteriocin-producing Lactobacillus plantarum LD4 was identified using biochemical and molecular techniques including 16S rDNA amplification, followed by sequencing. Bacteriocin production started after 3 h, reaching a maximum during the early stationary phase. Bacteriocin present in cell-free supernatant showed stability in a pH range of 2.0 to 6.0, as well as at different temperatures (60–100 and 121 °C for 15 min under 15 psi pressure). Antimicrobial activity was not affected by catalase, lipase or α-amylase, but was reduced in the presence of trypsin and protease, suggesting the proteinaceous nature of the compound. Activity remained stable after treatment with different organic solvents, surfactants, and detergents. The molecular weight of bacteriocin LD4 was found to be ∼6 kDa using tricine SDS-PAGE. Antimicrobial activity was demonstrated against Gram-positive and Gram-negative bacteria including Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Vibrio sp., Enterobacter cloacae, Enterococcus faecium, and a few strains of lactic acid bacteria and haloarchaea. Bacteriocin LD4 caused K+ ion efflux in target cells, suggesting the pore-forming nature of the compound. Given the stability under various conditions and the broad antimicrobial spectrum against pathogens, the bacteriocin LD4 has the potential for application in food safety as well as therapeutics.

https://link.springer.com/article/10.1007/s13213-016-1230-6