Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India.
J Appl Microbiol. 2019 Apr;126(4):1059-1069. doi: 10.1111/jam.14203. Epub 2019 Feb 18.
To understand the bactericidal action of enterocin LD3 against Gram-negative bacteria.
Minimum inhibitory concentration (MIC) of enterocin LD3 against Micrococcus luteus MTCC 106 and Escherichia coli NCDC 135 was 80 and 112 μg ml , and minimum bactericidal concentration (MBC) was 128 and 180 μg ml , respectively. The efflux of potassium ion (K ) was 14 and 13 ppm and electrical conductivity 10·5 and 8·3 mS cm in cell-free supernatant of MIC-treated cells of M. luteus and E. coli respectively. The increased absorbance (OD ) 0·422/0·260 and 0·110/0·075 in the bacteriocin-treated cells of M. luteus MTCC 106 and E. coli, NCDC 135, respectively, suggested the release of nucleic acids and proteins. The higher infrared absorbance at 1451·82 and ~1094·30 cm further suggested its interaction with cell membrane and nucleic acids of the target bacteria. The interaction of bacteriocin with nucleic acids was also confirmed using gel retardation assay. Transmission electron microscopy of the bacteriocin-treated cells revealed disruption of cell membrane and leakage of cytoplasmic contents.
Enterocin LD3 demonstrates bactericidal activity against Gram-negative bacteria interacting with cell membrane and nucleic acids.
The study discloses the possible mechanism of action of enterocin LD3 against Gram-negative bacteria which is a rare phenomenon.
了解肠菌素 LD3 对革兰氏阴性菌的杀菌作用。
肠菌素 LD3 对藤黄微球菌 MTCC 106 和大肠杆菌 NCDC 135 的最小抑菌浓度（MIC）分别为 80 和 112μg/ml，最小杀菌浓度（MBC）分别为 128 和 180μg/ml。MIC 处理后的细胞无细胞上清液中钾离子（K+）流出分别为 14 和 13ppm，电导率分别为 10.5 和 8.3mS/cm。藤黄微球菌 MTCC 106 和大肠杆菌 NCDC 135 的菌胞内吸光度（OD）0.422/0.260 和 0.110/0.075 的增加表明核酸和蛋白质的释放。在藤黄微球菌 MTCC 106 和大肠杆菌 NCDC 135 的菌胞内，更高的红外吸收在 1451.82 和~1094.30cm-1 处进一步表明其与靶细菌的细胞膜和核酸相互作用。用凝胶阻滞试验也证实了抗菌肽与核酸的相互作用。抗菌肽处理后的细胞透射电子显微镜显示细胞膜破裂和细胞质内容物泄漏。
肠菌素 LD3 对革兰氏阴性菌具有杀菌活性，与细胞膜和核酸相互作用。
该研究揭示了肠菌素 LD3 对革兰氏阴性菌的作用机制，这是一个罕见的现象。
