The antifungal activity of RsAFP2, a plant defensin from Raphanus sativus, involves the induction of reactive oxygen species in Candida albicans
The antifungal activity of RsAFP2, a plant defensin from Raphanus sativus, involves the induction of reactive oxygen species in Candida albicans
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DOI：
10.1159/000104753
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发表时间：
2007-01-01
影响因子：
1.2
通讯作者：
Thevissen, Karin
中科院分区：
文献类型：
--
作者：
Aerts, An M.;Francois, Isabelle E. J. A.;Thevissen, Karin
RsAFP2（Raphanus sativus antimicrobial peptide 2）是从萝卜种子中分离得到的一种抗真菌植物防御素。sativus与敏感酵母和真菌膜中的葡糖神经酰胺（GlcCer）相互作用，并诱导膜透化和真菌细胞死亡。然而，使用含有纯化GlcCer的含羧基荧光素的小单层囊泡，我们不能观察到作为插入RsAFP2在这样的囊泡中的结果的透化。因此，我们集中在一个假定的RsAFP2诱导的信号级联下游的RsAFP2结合到真菌膜中的GlcCer。我们发现，RsAFP2诱导活性氧簇（ROS）在白色念珠菌野生型的剂量依赖性的方式，但不是在所有的RsAFP2耐药三角洲gcs C。白色念珠菌突变体，在其膜中缺乏RsAFP2结合位点。这些发现表明RsAFP2与GlcCer的上游结合是ROS产生所需的，导致酵母细胞死亡。此外，抗氧化剂抗坏血酸阻断RsAFP2诱导的ROS产生，以及RsAFP2抗真菌活性。这些数据表明存在细胞内植物防御素诱导的信号级联，其涉及ROS产生并导致真菌细胞生长停滞。版权所有（c）2007 S. Karger AG，巴塞尔。
RsAFP2 (Raphanus sativus antifungal peptide 2), an antifungal plant defensin isolated from seed of R. sativus, interacts with glucosylceramides (GlcCer) in membranes of susceptible yeast and fungi and induces membrane permeabilization and fungal cell death. However, using carboxyfluorescein-containing small unilamellar vesicles containing purified GlcCer, we could not observe permeabilization as a consequence of insertion of RsAFP2 in such vesicles. Therefore, we focused on a putative RsAFP2-induced signaling cascade downstream of RsAFP2-binding to GlcCer in fungal membranes. We show that RsAFP2 induces reactive oxygen species (ROS) in Candida albicans wild type in a dose-dependent manner, but not at all in an RsAFP2-resistant Delta gcs C. albicans mutant that lacks the RsAFP2-binding site in its membranes. These findings indicate that upstream binding of RsAFP2 to GlcCer is needed for ROS production leading to yeast cell death. Moreover, the antioxidant ascorbic acid blocks RsAFP2-induced ROS generation, as well as RsAFP2 antifungal activity. These data point to the presence of an intracellular plant defensin-induced signaling cascade, which involves ROS generation and leads to fungal cell growth arrest. Copyright (c) 2007 S. Karger AG, Basel.