• The Plant Pathology Journal
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• v.27 no.1
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• pp.8-13
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• 2011

The induced resistance of cucumber leaves treated with oligochitosan to the infection of the cucumber powdery mildew, Sphaerotheca fuliginea, was investigated using transmission electron microscopy. The results showed that when the plants were treated with oligochitosan and challenged with inoculum, a significant decrease of the disease occurred. The mycelial development in the treated leaves was markedly inhibited. The cytoplasm of the powdery mildew mycelium was aggregated, with its organelles disintegrated and the cytoplasm collapsed. The protoplasm in haustoria became electron-dense. Haustoria became malformed, their organelles disintegrated, the hausterial wall thickened and eventually the whole complex necrotized. The host cells produced defence structures and materials associated with infection and a hypersensitive response. The host cell wall was thickened and deeply stained; several layers of papilla structure were produced under the cell wall; dark materials were deposited between the cell wall and plasmalemma; extrahaustorial plasmalemma was deeply stained and extrahaustorial matrix appositions had large deposits of electron-dense material; the cytoplasm was disordered, host organelles disintegrated and eventually the whole host cell disintegrated and necrotized.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.94-95
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• 2000

Chitosan은 식품산업, 의료·의약, 환경, 농업 등 거의 분야에서 광범위하게 응용되고 있는 새로운 천연 기능성 물질이다. 최근에는 항균작용 등 생리활성 기능을 나타내는 chitosan 및 oligochitosan을 활용하여 식품의 유통기간 연장을 위한 연구가 보고되고 있다. Chitosan은 축육소세지 (Park et al., 1999) 및 김치 (Yoo et al., 1998; No et al., 1995)에 대하여 보존효과를 나타내었으나 저염 명란젓 (Kim, 1996)에는 보존 효과가 거의 없다고 보고되고 있다. 본 실험에서는 저염 창란젓의 유통기간 연장 및 기능성 강화를 할 목적으로 chitosan 및 oilgochitosan을 첨가한 창란젓의 숙성기간에 따른 보존성을 연구하였다. (중략)

• Research in Plant Disease
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• v.17 no.2
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• pp.129-135
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• 2011

Chitosan is a linear polysaccharide composed of randomly distributed ${\ss}$-(1-4)-linked D-glucosamine and Nacetyl-D-glucosamine. There have been many reports on the induced systemic resistance and in vivo antifungal activities of higher molecular weight chitosans with molecular weights over 3,000 amu (atomatic mass unit), but there are few papers on in vivo antifungal activities of low molecular weight chitosans (oligochitosans) with molecular weights less than 3,000 amu. In our study, an oligochitosan sample (320.3,000 amu) showed a potent 1-day protective activity with control values more than 94% at concentrations of 500 and 1,000 ${\mu}g$/ml especially against tomato late blight caused by Phytophthora infestans under growth chamber conditions. It also displayed a moderate 1-day protective activity with control values of 67.89% at concentrations of 500 and 1,000 ${\mu}g$/ml against wheat leaf rust and red pepper anthracnose. On the other hand, it showed a 16-hr curative activity against red pepper anthracnose, but not against tomato late blight and wheat leaf rust. In field experiments, oligochitosan effectively suppressed the development of late blight on potato and tomato plants with control values of 72% and 48%, respectively. The results strongly indicate that oligochitosan can be used as an eco-friendly organic material for the control of late blight on tomato and potato plants.