• 한국환경과학회지
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• 제23권9호
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• pp.1601-1608
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• 2014

Plasma reactor was used for the inactivation of Phytophthora capsici which is phytophthora blight pathogen in aquiculture. Effects of first voltage, second voltage, air flow rate, pH, incubation water concentration were examined. At the low $1^{st}$ voltage, under 80 V, the lag phase was noticed within 30 sec, however, it was not shown over 100 V. The variation of optimum operation condition was not shown by the variation of microorganisms. However, the inactivation rate was different by the variation of species of microorganisms. The inactivation rate and efficiency were increased by the increase of $2^{nd}$ voltage. The highest initial inactivation rate was shown at pH 3 and the rate was decreased by the increase of pH. The inactivation rate increased by the increase of air flow rate, however, it was shown as similar at the rate of 4 L/min and 5 L/min. The inactivation rate was distinctly decreased at the three times concentration of incubation solution comparing at the distilled water and basic incubation solution.

• 한국환경과학회지
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• 제33권5호
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• pp.323-332
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• 2024

Circulating hydroponic cultivation has the advantage of reducing soil and water pollution problems caused by discharge of fertilizer components because the nutrient solution is reused. However, cyclic hydroponic cultivation has a low biological buffering capacity and can cause outbreaks of infectious root pathogens. Therefore, it is necessary to develop technologies or disinfection systems to control them. This study used dielectric barrier discharge plasma, which generates various persistent oxidants, to treat Fusarium oxysporum f. sp., a pathogen that causes wilt disease. Batch and intermittent continuous inactivation experiments were conducted, and the results showed that the total residual oxidant was persistent in intermittent plasma treatment at intervals of 2-3 days, and F. oxysporum was treated efficiently. Intermittent plasma treatment did not inhibit the growth of tomatoes.

• The Plant Pathology Journal
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• 제32권2호
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• pp.157-161
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• 2016

Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc). Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika.

• 대한방사선기술학회지:방사선기술과학
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• 제45권2호
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• pp.165-170
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• 2022

Staphylococcus aureus is a major pathogen that causes clinical infections in humans and can also cause massively colonized in lesion skin, particularly in atopic dermatitis patients. This study investigated the effects of photodynamic inactivation with radachlorin and diode laser irradiation on the viability of S. aureus in vitro and assessed the effects of the dose of laser transmission. In the PDI group, 5 𝜇L of S. aureus suspension and 5 𝜇L of radachlorin were inoculated in a 55 mm petri dish (63.6 cm²). The samples were placed in a 37° incubator for 30 min and then irradiated with light (660 nm diode laser). After laser irradiation, the cells were stored for 24 h at 37° in an incubator with 5% CO2, and the number of colonies was counted. All CFU/mL of S. aureus were reduced by diode laser in the presence of radachlorin, with a killing rate of 87.9% at an energy dose of 9 J/cm². This study contribute to treat colonized with S. aureus in atopic dermatitis patients and wound infections by providing information on the optimal dose of laser transmission using PDI to eliminate S. aureus.

• 환경생물
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• 제19권3호
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• pp.211-217
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• 2001

식물의 저항성과 방어관련물질 유도에 관련된 salicylate가 담배 미분화세포로부터 분리된 isoperoxidase $A_3$의 활성에 미치는 영향을 살펴보고, $Fe^{2+}$ 의 첨가에 의하여 salicylate에 의한 효소활성 억제가 보호되는 양상을 조사하였다. 다양한 농도의 salicylate가 isoperoxidase $A_3$의 활성에 미치는 영향을 조사한 결과 0.48mM salicylate에 의하여 isoperoxidase $A_3$의 활성이 약 20% 감소되었고, 0.6mM salicylate에 의하여 효소활성이 85% 이상 감소되었다. 이러한 결과는 salicylate에 의하여 isoperoxiase $A_3$가 억제됨을 보여준다. Salicylate에 의한 isoperoxidase $A_3$의 억제반응은 pH 의존적으로 일어났을 뿐만 아니라, noncompetitive inhibition 양상을 나타냈다. 뿐만 아니라 salicylate에 의한 isoperoxidase $A_3$의 활성억제는 $Fe^{2+}$ 첨가에 의하여 거의 완벽하게 보호되었다. Isoeroxidase A3로부터 heme부분을 제거하여 apoperoxidase를 제조한 후 여러가지 금속이온이 apoperoxidase의 활성회복에 미치는 효과를 조사하였다. 그 결과 hemin과 $Fe^{2+}$ 첨가에 의하여 apoperoxidase의 활성이 80% 이상 회복되었으나 $Cu^{2+},\;Zn^{2+},\;Co^{2+},\;Mn^{2+}$ 등은 apoperoxidase의 활성을 재구성시키지 못하였다.

• Fisheries and Aquatic Sciences
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• 제19권6호
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• pp.28.1-28.7
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• 2016

Background: Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm) on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results: We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and $68.4J\;cm^{-2}$, respectively, produced one log reduction in the bacterial populations), whereas Streptococcus parauberis was the least susceptible ($153.8J\;cm^{-2}$ per one log reduction). In general, optical density (OD) values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions: This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

• 대한환경공학회지
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• 제32권11호
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• pp.1063-1068
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• 2010

본 연구는 유효한 분변오염의 지표 미생물로서 제안되고 있는 E.coli와, 병원성 바이러스에 대한 지표 미생물로 추천되는 $Q{\ss}$ 파지의 UV 및 UV/$H_2O_2$에 대한 내성을 비교하였다. 이 결과에 의거, 병원성 바이러스 관리를 위한 E.coli 규제의 유효성을 고찰하였다. 또한, 병원성 바이러스에 대한 대체 지표 미생물로써, $Q{\ss}$ 파지, T4 및 lambda 파지의 실제 하수 2차 처리 수중에서의 UV 불활성화를 비교하였다. 실험결과, $Q{\ss}$ 파지와 E.coli는 UV에 대해 거의 동등한 내성을 보였으나, UV/$H_2O_2$ 공정에 대해서는 E.coli보다 $Q{\ss}$ 파지가 더 높은 내성을 보였다. 이로부터, $Q{\ss}$ 파지가 모든 병원성 바이러스의 UV 또는 UV/$H_2O_2$에 대한 내성을 대표한다고 할 수는 없을지라도, 지표 미생물로써 E.coli의 불활성화 효과에만 의존하는 것은, 소독공정에 따라서는 바이러스류에 대해 충분한 소독효과를 얻지 못할 수도 있음을 알 수 있었다. 한편, T4 및 lambda 등 DNA 파지와 불활성화를 비교하였을 경우, $Q{\ss}$ 파지가 UV에 대해 더 낮은 내성을 보였다. 따라서, 불활성화에 대한 지표 바이러스로써 $Q{\ss}$ 파지의 이용은 낮은 UV 조사량의 도입에 의해 결과적으로 불충분한 소독효과를 초래할 수도 있을 것 같다. 이 결과는, 병원성 바이러스류에 대해 보다 충분한 불활성화를 달성하기 위해서는 RNA 파지인 $Q{\ss}$보다 T4 및 lambda 등 DNA 파지가 지표 바이러스로써 보다 유효할 수 있음을 보여준다.

• 한국잠사곤충학회지
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• 제32권2호
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• pp.105-109
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• 1990

포르말린에 과망간산카리(KMnO4)를 넣어 화학적 반응에 의하여 발생되는 포름알데히드 가스로 누에고름병 바이러스의 불활화와 흰굳음병균에 대한 소독시험을 실시하여 다음과 같은 결과를 얻었다. 1. 누에고름병 바이러스(Nuclear polyhedrosis virus)의 불활화는 잠실면적 3.3$m^2$당 포르말린 25$m\ell$에 과망간산카리 10g을 혼합하여 하룻방 동안 훈연소독을 실시하였을 때 상당한 수준의 소독효과가 있었고 같은 잠실단위 면적에 포르말린 75$m\ell$와 과망간산카리 30g을 혼합하여 하룻밤 동안 훈연상태를 유지하였을 때는 거의 완전한 불활화가 이루어졌다. 2. 노란굳음병균에 대한 살균효과는 잠실면적 3.3$m^2$당 포르말린 50$m\ell$에 과망간산카리 20g을 반응시켜 훈연소독을 실시하였을 때는 처리받은 균의 자람이 상당한 수준 억제되었고 같은 단위면적에 포르말린 75$m\ell$와 과망간산카리 30g을 혼합시켰을 때는 완전한 살균이 이루어졌다. 3. 포르말린 훈연소독에 의한 누에에 미치는 영향은 4령 1일째와 5령 1일째 2회와 4령 1일째, 5령 1,3일째 각 1회씩 3회를 처리하였을 때(훈연소독은 저녁급상후에 실시하고 다음날 아침 급상때까지 유지시킴) 전견종, 견층중, 견층비율, 유충기간(4-5령) 등에서는 무처리와 차이가 없었으나 3회 처리시에는 실품림새율은 무처리에 비하여 약간 떨어졌다.

• The Plant Pathology Journal
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• 제33권3호
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• pp.276-287
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• 2017

RcsA is a positive activator of extracellular polysaccharide (EPS) synthesis in the Enterobacteriaceae. The rcsA gene of the soft rot pathogen Pantoea sp. strain PPE7 in Pleurotus eryngii was cloned by PCR amplification, and its role in EPS synthesis and virulence was investigated. The RcsA protein contains 3 highly conserved domains, and the C-terminal end of the open reading frame shared significant amino acid homology to the helix-turn-helix DNA binding motif of bacterial activator proteins. The inactivation of rcsA by insertional mutagenesis created mutants that had decreased production of EPS compared to the wild-type strain and abolished the virulence of Pantoea sp. strain PPE7 in P. eryngii. The Pantoea sp. strain PPE7 rcsA gene was shown to strongly affect the formation of the disease symptoms of a mushroom pathogen and to act as the virulence factor to cause soft rot disease in P. eryngii.

• 상하수도학회지
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• 제24권3호
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• pp.333-339
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• 2010

Particle removal is an important step taken at water treatment plants (WTPs) for the safety of tap water due to its proportionality to the pathogen inactivation. Government promulgated a treatment technique for the optimization of filtration including continuous turbidity monitoring using on-line turbidimeters. Based on the turbidity measurements of 460 filters at 31 WTPs operated by K-water, the evaluation of filtration performance and the investigation of major causes related to particle breakthrough were explored. 98.1 % of the filters had an effluent turbidity measurement which was less than 0.1 NTU, but turbidity breakthrough of more than 0.3 NTU was noticed occasionally which is in violation of AWWA 5-Star guidelines. It was shown that the optimization of coagulation, filter-to-waste, the observance of optimal filtration velocity and backwashing process based on filtrate turbidity were crucial for the improvement of filtrate.