• The Plant Pathology Journal
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• 제33권3호
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• pp.318-328
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• 2017

Chitinase-producing Paenibacillus elgii strain HOA73 has been used to control plant diseases. However, the antimicrobial activity of its extracellular chitinase has not been fully elucidated. The major extracellular chitinase gene (PeChi68) from strain HOA73 was cloned and expressed in Escherichia coli in this study. This gene had an open reading frame of 2,028 bp, encoding a protein of 675 amino acid residues containing a secretion signal peptide, a chitin-binding domain, two fibronectin type III domains, and a catalytic hydrolase domain. The chitinase (PeChi68) purified from recombinant E. coli exhibited a molecular mass of approximately 68 kDa on SDS-PAGE. Biochemical analysis indicated that optimum temperature for the actitvity of purified chitinase was $50^{\circ}C$. However, it was inactivated with time when it was incubated at $40^{\circ}C$ and $50^{\circ}C$. Its optimum activity was found at pH 7, although its activity was stable when incubated between pH 3 and pH 11. Heavy metals inhibited this chitinase. This purified chitinase completely inhibited spore germination of two Cladosporium isolates and partially inhibited germination of Botrytis cinerea spores. However, it had no effect on the spores of a Colletotricum isolate. These results indicate that the extracellular chitinase produced by P. elgii HOA73 might have function in limiting spore germination of certain fungal pathogens.

• The Plant Pathology Journal
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• 제32권5호
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• pp.460-468
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• 2016

To study the control of postharvest decay caused by Colletotrichum gloeosporioides and Penicillium expansum, gamma irradiation alone or in combination with fumigation was evaluated to extend the shelf life of apples in South Korea. An irradiation dose of 2.0 kGy resulted in the maximum inhibition of C. gloeosporioides and P. expansum spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.22 and 0.35 kGy for C. gloeosporioides and P. expansum, respectively. Microscopic observations revealed that when the fungal spores were treated with gamma irradiation (4.0 kGy), conidial germination was stopped completely resulting in no germ tube formation in C. gloeosporioides. Treatment with the eco-friendly fumigant ethanedinitrile had a greater antifungal activity against C. gloeosporioides and P. expansum in comparison with the non-treated control under in vitro conditions. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments to control postharvest decay on stored apples. Interestingly, when apples were treated with gamma irradiation in combined with fumigation, disease inhibition increased more at lower (< 0.4 kGy) than at higher doses of irradiation, suggesting that combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions.

• 생명과학회지
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• 제21권8호
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• pp.1094-1099
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• 2011

초고압의 미생물에 대한 살균 효과는 다른 제어 방법을 더 적용함으로써 증대 될 수 있다. 본 연구의 목적은 식품 산업에서 중요한 세균 포자들을 tert-butylhydroquinone (TBHQ)를 처리하여 초고압 살균효과를 증진시킴을 알아보고자 한다. Clostridium sporogenes, Bacillus cereus, Bacillus subtilis의 포자를 준비하였다. Dimetylsulfoxide(DMSO)에 용해시킨 TBHQ 200 ppm을 함유한 포자액을 650 또는 700 MPa로, 54-72$^{\circ}C$에서 5분간 처리하였다. 세균 포자의 사멸은 초고압 처리 이후에만 일어났다. Bacillus subtilis 포자가 B. cereus나 C. sporogenes 포자보다 초고압에 의해 더 많이 사멸되었다. C. sporogenes 포자의 사멸은 Bacillus 포자에 비해서 초고압에 의한 germination이 더 일어나면서 이루어 졌다. Bacillus 포자는 54$^{\circ}C$에서 초고압 처리 때 보다 72$^{\circ}C$에서 처리했을 때 더 많이 사멸되었다. 하지만 germination에 의한 사멸은 70$^{\circ}C$에서 감소되었다. 포자를 DMSO와 초고압, TBHQ와 초고압의 병용 처리를 했을 때, 특히 54$^{\circ}C$에서는 포자 사멸이 덜 일어났다. 세균 포자의 사멸에 대한 좀 더 나은 이해를 위해서는 초고압에 의한 germination 과 다른 포자 억제 물질과의 상호 작용에 대한 메커니즘 연구들이 필요하다.

• 한국토양비료학회지
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• 제45권4호
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• pp.582-592
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• 2012

Microorganisms present in the rhizosphere soil plays a vital role in improving the plant growth and soil fertility. Many kinds of fertilizers including chemical and organic has been approached to improve the productivity. Though some of them showed significant improvement in yield, they failed to maintain the soil properties. Rather they negatively affected soil eventually, the land became unsuitable for agricultural. To overcome these problems, microorganisms have been used as effective alternative. For past few decades, plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) have been used as effective inoculants to enhance the plant growth and productivity. PGPR improves the plant growth and helps the plant to withstand biotic and abiotic stresses. AM fungi are known to colonize roots of plants and they increase the plant nutrient uptake. Spore associated bacteria (SAB) are attached to spore wall or hyphae and known to increase the AMF germination and root colonization but their mechanism of interaction is poorly known. Better understanding the interactions among AMF, SAB and PGPR are necessary to enhance the quality of inoculants as a biofertilizers. In this paper, current knowledge about the interactions between fungi and bacteria are reviewed and discussed about AMF spore associated bacteria.

• 식물병연구
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• 제8권2호
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• pp.124-130
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• 2002

1998년 전남 신안군의 양파 상온 저장고에서 발생한 검은색의 곰팡이는 검은곰팡이병을 일으키는 Aspergillusniger로 동정되었다. A. niger AnYD-1은 3$0^{\circ}C$에서 균사생장, 포자발아 그리고 양파에 대한 병원성이 가장 양호하였다. PDA 배지 상에서 실시한 in vitro의 실험에서 flusilazole과 hexaconazole은 A. niger AnYD-1의 균사 생장 억제 효과는 적었지만, 병원균에 살균제를 직접 처리하지 않고 증기 상태로 처리하였을 때 포자의 형성을 강하게 억제하는 특이적 인 훈증효과를 보였다. Flusilazole과 hexaconazole의 훈증의 효과는 사용하는 용매, 처리 농도와 배양 온도에 따라서 차이가 있었다. Dimethylsulfoxide와 dimethylformamide를 용매로 사용하였을 때 가장 높은 효과가 나타났으며, 고온에서 배양할수록 포자형성 억제 효과가 크게 나타났다.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.236-242
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• 1995

Biological control of soilborne plant pathogens by the addition of antagonistic microorganisms to the soil may offer a practical supplement or alternative to existing disease management strategies that depend heavily on chemical pesticides. Soil amendment with antagonistic microbes was non-effective because of high cost, low efficacy, and inconvenient usage on the treatment course. Therefore, seed coating formulation for the application of biological seed treatments has been being to apply successful disease suppression for many important crops. The objectives of this study were to investigate the optimal condition for the spore production of biocontrol agent Bacillus subtilis YBL-7 and the liquid coating formulation that contained a suspension of a proper aqueous binder, as well as a ground fine solid particulate material. The maximum yield has been obtained from 60 hrs-old culture at 30$\circ$C in spore forming (SF) medium containing 0.8% nutrient broth, 0.05% yeast extract, 10$^{-1}$ M MgCl$^{2}$, 10$^{-4}$ M MnCl$^{2}$, 10$^{-5}$ M dipicolinic acid, and pH 6.5. The optimal condition of dried spore preparation was achieved when cells of B. subtilis YBL-7 was heat-dried with 50$\circ$C for 2 hrs.

• Fisheries and Aquatic Sciences
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• 제19권1호
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• pp.7.1-7.6
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• 2016

In nature, marine mussels (Mytilus edulis) suffer less fouling colonization on the newly formed sides of their shells. Using settlement assays with algal spores of Porphyra suborbiculata, we determined that spore attachment and germination on the periostracum decreased to 36.8 and 3.3 %, respectively. Additionally, the spore settlement was considerably diminished by periostracum dichloromethane extracts containing 19 % oleamide, a major antifouling compound. A scanning electron micrograph of the surface revealed a regular ripple structure with approximately $1.4{\mu}m$ between ripples. Based on these results, mussel periostraca or their associated biomimetic materials may become environmentally friendly, antifouling agents for preventing the settlement of soft foulants.

• 식물병연구
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• 제30권2호
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• pp.131-138
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• 2024

당근검은잎마름병을 일으키는 A. dauci의 포자 생장 시기에 따른 chlorothalonil, dithianon, folpet, iminoctadine trisalbesilate, fluazinam의 효과를 포자 생존 검정법과 한천희석법으로 검정하였다. 포자 생존 검정법과 한천희석법으로 조사한 A. dauci CDSGM2-5를 비롯한 7개 균주의 chlorothalonil 에 대한 평균 EC₅₀값은 14.21 ㎍/ml와 100 ㎍/ml 이상이었다. Dithianon과 folpet 역시 포자 생존 검정법의 EC₅₀값이 한천희석법보다 낮았지만, iminoctadine tris-albesilate는 한천희석법으로 조사한 EC₅₀값이 더 낮았다. Fluazinam은 포자 생존 검정법과 한천희석법의 EC₅₀값이 각각 1.63 ㎍/ml와 2.40 ㎍/ml로, 두 방법의 EC₅₀값이 비슷하였다. A. dauci KACC 42997의 포자생장 단계에 따라 각 살균제를 처리한 결과, chlorothalonil, dithianon, folpet은 포자가 발아한 이후에 처리하면 발아하기 전에 처리하였을 때보다 효과가 감소하였으나, iminoctadine trisalbesilate는 포자 접종과 동시에 처리하였을 때 10.28 ㎍/ml였던 EC₅₀값이 포자가 발아한 후에 처리하면 2.68 ㎍/ml에서 3.21㎍/ml까지 감소하여, 포자 발아 후에 처리하였을 때 효과가 우수하였다. Fluazinam은 접종하는 포자에서 발아관이 장경보다 길게 발아한 포자까지 처리하여도 포자의 생장을 크게 억제하였다. 하지만 iminoctadine tris-albesilate와 fluazinam을 12시간을 배양한 후에 처리하면 EC₅₀값이 8.87 ㎍/ml와 20.65 ㎍/ml로 상승하면서 억제 효과가 감소하였다. 본 연구 결과는 살균제의 적합한 처리 시기는 병원균의 포자 생장 시기에 따라서 달라짐을 보여주고 있다. 따라서 살균제 처리 시기의 결정은 병원균의 생장 시기에 대한 살균제의 효과까지도 고려해야 할 것으로 생각되어진다.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.524-529
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• 2007

Pressure inactivation behavior of Bacillus amyloliquefaciens spores was investigated in deionized water. The spores of B. amyloliquefaciens were subjected to $105^{\circ}C$ and 700 MPa. The magnitude of the decrease in viability after pressure treatment was similar to that after pressure treatment followed by heat shock. The increase of dipicolinic acid (DPA) release was correlated with the spore inactivation, and the hydrophobicity did not significantly change during the pressure-assisted thermal processing (PATP). Lag phase duration increased with increasing pressure process time. The mechanisms of spore germination and inactivation during the PATP were related to a complex physiological process.

• 한국식품위생안전성학회지
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• 제1권2호
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• pp.115-120
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• 1986

This experiment was carried out to develop long-term preservable meat products by controlling a water activity which has a potential inhibitory effects on the growth of microorganism and germination of spore. For this purpose the accuracy of instrument for the measurement of water activity, electric hygrometer was used for this study as well as water activity of final products were investigated according to the various amounts of different kinds of additives. Spore of Bacillus spp, Clostridium sporogenes and Cl. botulinum were inoculated to the meat products with different aw and their growth states in $25^{\circ}C$ were observed to find out the lowest aw which inhibit their growth (aw 0.950).