摘要 :
The mechanism of action of oligochitosan, which has shown great antifungal activity against Phytophthora capsici in vitro, was studied using 2-aminoacridone-labeled oligochitosan (2-AMAC-oligochitosan) and a gel-retardation experi...
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The mechanism of action of oligochitosan, which has shown great antifungal activity against Phytophthora capsici in vitro, was studied using 2-aminoacridone-labeled oligochitosan (2-AMAC-oligochitosan) and a gel-retardation experiment. Internalization of 2-AMAC-oligochitosan in cysts, germtubes and sporangia of P. capsici was confirmed by confocal laser scan microscopy (CLSM), and the degree of uptake depended on the incubation concentration. 2-AMAC-oligochitosan localized mainly in the cytoplasm and showed no binding to both cell wall and cell membrane. Mannose, an inhibitor for oligochitosan uptake by macrophages, could not inhibit the internalization of oligochitosan in P. capsici. The gel-retardation experiment showed that oligochitosan bound strongly to DNA and RNA of P. capsici. These results indicate that oligochitosan exerts its antifungal activity by penetrating the cell membrane and putative binding to intracellular targets such as DNA and RNA..
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摘要 :
Antifungal activity of oligochitosan against nine phytopathogens was investigated in vitro. Oligochitosan was more effective than chitosan in inhibiting mycelial growth of Phytophthora capsici and its inhibition on different stage...
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Antifungal activity of oligochitosan against nine phytopathogens was investigated in vitro. Oligochitosan was more effective than chitosan in inhibiting mycelial growth of Phytophthora capsici and its inhibition on different stages in life cycle of P. capsici was observed. Rupture of released zoospores induced by oligochitosan was reduced by addition of 100 mM glucose. The effects of oligochitosan on mycelial growth and zoospore release, but not zoospore rupture, were reduced largely when pH value was above 7. The ultrastructural study showed that oligochitosan caused distortion and disruption of most vacuoles, thickening of plasmalemma, and appearance of unique tubular materials. Plasmalemmasomes in hyphal tip cells were not found in the presence of oligochitosan. These results suggest polycationic nature of oligochitosan contributes only partly to its antifungal activity and multiple modes of action of oligochitosan exist including the disruption of endomembrane system..
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