Dependence of synergistic fungicidal activity of Cu2+ and allicin, an allyl sulfur compound from garlic, on selective accumulation of the ion in the plasma membrane fraction via allicin-mediated phospholipid peroxidation
Dependence of synergistic fungicidal activity of Cu2+ and allicin, an allyl sulfur compound from garlic, on selective accumulation of the ion in the plasma membrane fraction via allicin-mediated phospholipid peroxidation
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DOI：
10.1055/s-2006-947167
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发表时间：
2006-08-01
期刊：
影响因子：
2.7
通讯作者：
Tanaka, Toshio
中科院分区：
文献类型：
--
作者：
Ogita, Akira;Fujita, Ken-ichi;Tanaka, Toshio
大蒜素能有效降低Cu2+对包括尖孢镰刀菌在内的多种真菌的致死浓度，使Cu2+对该真菌的最低杀菌浓度(MFC)降至未加大蒜素时的2%。在酿酒酵母中，当单独加入非致死浓度的Cu2+时，细胞不明显地摄取Cu2+，而在大蒜素存在的情况下，Cu2+被有效地结合到细胞中，就像在致死浓度的离子处理细胞的情况下一样。尽管大蒜素可能通过促进质膜磷脂过氧化而增加细胞对Cu2+的通透性，但这些细胞表面事件并不导致内源活性氧(ROS)的产生，这是典型的离子毒性效应。在致死浓度的离子处理的细胞质中检测到Cu2+，而在低浓度的离子与大蒜素联合处理时，离子被包裹在质膜部分。通过提取疏水蛋白而不是提取磷脂，Cu2+可以从质膜组分中被溶解，这表明大蒜素处理后它与质膜蛋白形成了络合作用。这种Cu2+的亚细胞定位导致细胞内K+的选择性渗漏，而不是对质膜的破坏性损伤，这被认为是Cu2+和大蒜素协同杀菌活性的基础。
Allicin was effective in decreasing the lethal concentration of Cu2+ against various fungal strains including a plant pathogen, Fusarium oxysporum, so that the minimum fungicidal concentration (MFC) of the ion for the fungus could be reduced to 2% of that detected without allicin. In Saccharomyces cerevisiae, Cu2+ was not apparently taken up by cells when added alone at a non-lethal concentration, whereas the ion was efficiently incorporated into cells in the presence of allicin, as in the case of cells treated with the ion at a lethal concentration. Although allicin likely increased cellular permeability to CU2+ due to its promotive effect on plasma membrane phospholipid peroxidation, these cell-surface events did not result in endogenous reactive oxygen species (ROS) production, a typical toxic effect of the ion. Cu2+ was detected in the cytoplasmic fraction of cells that had been treated with the ion at a lethal concentration, whereas the ion was entrapped in the plasma membrane fraction upon their treatment with the ion at a low concentration in combination with allicin. Cu2+ could be solubilized from the plasma membrane fraction by a procedure for the extraction of hydrophobic proteins rather than the extraction of phospholipids, suggesting its complexation with a plasma membrane protein as a result of allicin treatment. Such a subcellular localization of Cu2+ resulted in the selective leakage of intracellular K+, but not in the disruptive damage on the plasma membrane, and was considered to underlie the synergistic fungicidal activity of Cu2+ and allicin.