Viejo-Díaz Mónica, Andrés María T, Fierro José F
Department of Functional Biology (Microbiology), Faculty of Medicine, University of Oviedo, C/Julian Claveria, 6, 33006 Oviedo, Asturias, Spain.
FEMS Immunol Med Microbiol. 2004 Oct 1;42(2):181-5. doi: 10.1016/j.femsim.2004.04.005.
Human lactoferrin is an innate host defence protein with antimicrobial activity that exerts a candidacidal effect in a cation concentration-dependent manner. We investigated the ability of this cationic protein (with an isoelectric point of 8.7) to permeabilize the cytoplasmic membrane of Candida albicans cells. Despite minor K(+)-release in lactoferrin-treated C. albicans cells, the killing effect was not related to an extensive membrane permeabilization, as indicated by: (a) the non-release of macromolecular cytosolic constituents; (b) the non-permeabilization for extracellular propidium iodide nor for intracellular accumulated calcein; and (c) the inability to disrupt the phospholipid bilayer of 8-aminonaphthalene-1,3,6, trisulfonic acid/p-xylene-bis-pyridiniumbromide-loaded liposomes. These results suggest that lactoferrin exerts its candidacidal effect through a mechanism different from membrane permeabilization described for other cationic peptides.
人乳铁蛋白是一种具有抗菌活性的先天性宿主防御蛋白，它以阳离子浓度依赖的方式发挥杀念珠菌作用。我们研究了这种阳离子蛋白（等电点为8.7）使白色念珠菌细胞质膜通透化的能力。尽管用乳铁蛋白处理的白色念珠菌细胞有少量钾离子释放，但如以下几点所示，其杀伤作用与广泛的膜通透化无关：（a）大分子胞质成分未释放；（b）细胞外碘化丙啶和细胞内积累的钙黄绿素均未通透；（c）无法破坏负载8-氨基萘-1,3,6-三磺酸/对二甲苯双吡啶溴化物的脂质体的磷脂双层。这些结果表明，乳铁蛋白通过一种不同于其他阳离子肽所描述的膜通透化的机制发挥其杀念珠菌作用。
