School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
Biochem Biophys Res Commun. 2010 Sep 24;400(3):352-7. doi: 10.1016/j.bbrc.2010.08.063. Epub 2010 Aug 22.
Psacotheasin is a 34-mer knottin-type peptide that is derived from Psacothea hilaris larvae. In this study, the antifungal activity and mechanism(s) by which psacotheasin affects human fungal pathogens were investigated. Psacotheasin shows remarkable antifungal properties without hemolytic activity against human erythrocytes. To understand the antifungal mechanism(s) of psacotheasin in Candida albicans, flow cytometric analysis with DiBAC(4)(3) and PI was conducted. The results showed that psacotheasin depolarized and perturbed the plasma membrane of the C. albicans. Three-dimensional (3D)-flow cytometric contour-plot analysis, accompanied by decreased forward scatter (FS), which indicates cell size, confirmed that psacotheasin exerted antifungal effects via membrane permeabilization. The membrane studies, using a single GUV and FITC-dextran (FD) loaded liposomes, indicate that psacotheasin acts as a pore-forming peptide in the model membrane of C. albicans and the radius of pores were presumed to be anywhere from 2.3 to 3.3nm. Therefore, the current study suggests that the mechanism(s) of psacotheasin's antifungal properties function within the membrane.
Psacotheasin 是一种 34 个氨基酸组成的纽扣型肽，来源于 Psacothea hilaris 幼虫。本研究旨在探究 Psacotheasin 对人类真菌病原体的抗真菌活性及其作用机制。Psacotheasin 对人红细胞无溶血活性，但具有显著的抗真菌特性。为了研究 Psacotheasin 在白色念珠菌中的抗真菌机制，我们采用 DiBAC（4）（3）和 PI 进行流式细胞术分析。结果表明，Psacotheasin 使白色念珠菌的质膜去极化和紊乱。三维（3D）流式细胞术等高线图分析伴随着前向散射（FS）的降低（FS 降低表明细胞体积减小），证实 Psacotheasin 通过破坏细胞膜发挥抗真菌作用。利用单个人 GUV 和 FITC-葡聚糖（FD）负载的脂质体进行的膜研究表明，Psacotheasin 作为一种孔形成肽在白色念珠菌模型膜中起作用，并且假定孔的半径在 2.3 到 3.3nm 之间。因此，本研究表明 Psacotheasin 的抗真菌特性的作用机制发生在膜内。
