Université de Lyon, Université Lyon 1 - ISARA Lyon, Bioingénierie et Dynamique Microbienne aux Interfaces Alimentaires, IUT Lyon 1 site de Bourg en Bresse - Technopole Alimentec, rue Henri de Boissieu, 01000 Bourg en Bresse, France.
Can J Microbiol. 2012 Dec;58(12):1353-61. doi: 10.1139/w2012-113. Epub 2012 Nov 25.
Polyhexamethylene biguanide (PHMB) is a cationic biocide. The antibacterial mode of action of PHMB (at concentrations not exceeding its minimal inhibitory concentration) upon Listeria innocua LRGIA 01 was investigated by Fourier transformed infrared spectroscopy and fluorescence anisotropy analysis. Fourier transformed infrared spectra of bacteria treated with or without PHMB presented some differences in the lipids region: the CH(2)/CH(3) (2924 cm(-1)/2960 cm(-1)) band areas ratio significantly increased in the presence of PHMB. Since this ratio generally reflects membrane phospholipids and membrane microenvironment of the cells, these results suggest that PHMB molecules interact with membrane phospholipids and, thus, affect membrane fluidity and conformation. To assess the hypothesis of PHMB interaction with L. innocua membrane phospholipids and to clarify the PHMB mode of action, we performed fluorescence anisotropy experiments. Two probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and its derivative 1-[4-(trimethyl-amino)-phenyl]-6-phenylhexa-1,3,5-triene (TMA-DPH), were used. DPH and TMA-DPH incorporate inside and at the surface of the cytoplasmic membrane, respectively. When PHMB was added, an increase of TMA-DPH fluorescence anisotropy was observed, but no changes of DPH fluorescence anisotropy occurred. These results are consistent with the hypothesis that PHMB molecules perturb L. innocua LRGIA 01 cytoplasmic membrane by interacting with the first layer of the membrane lipid bilayer.
聚六亚甲基双胍（PHMB）是一种阳离子型杀菌剂。通过傅里叶变换红外光谱和荧光各向异性分析，研究了 PHMB（浓度不超过最小抑菌浓度）对无毒李斯特菌 LRGIA 01 的抗菌作用模式。用 PHMB 处理或未处理的细菌的傅里叶变换红外光谱在脂质区域呈现出一些差异：在 PHMB 的存在下，CH(2)/CH(3)（2924 cm(-1)/2960 cm(-1)）带面积比显著增加。由于该比值通常反映了细胞膜磷脂和细胞的膜微环境，这些结果表明 PHMB 分子与细胞膜磷脂相互作用，从而影响膜的流动性和构象。为了评估 PHMB 与无毒李斯特菌细胞膜磷脂相互作用的假设，并阐明 PHMB 的作用模式，我们进行了荧光各向异性实验。使用了两种探针，1,6-二苯基-1,3,5-己三烯（DPH）及其衍生物 1-[4-（三甲基氨基）-苯基]-6-苯基己-1,3,5-三烯（TMA-DPH）。DPH 和 TMA-DPH 分别掺入细胞质膜的内部和表面。当添加 PHMB 时，观察到 TMA-DPH 荧光各向异性增加，但 DPH 荧光各向异性没有变化。这些结果与 PHMB 分子通过与膜脂双层的第一层相互作用来扰乱无毒李斯特菌 LRGIA 01 细胞质膜的假设一致。
