• 농약과학회지
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• 제10권3호
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• pp.201-209
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• 2006

43종의 식물오일들을 대상으로 잿빛곰팡이병균 (Botrytis cinerea) 외 9종의 식물병원균에 대한 살균 효과로 이들의 생리활성 검증을 실시하였다. 이 중 thyme 오일이 잿빛곰팡이병균(Botrytis cinerea), 잎집무늬 마름병균(Rhizoctonia solani), 고추역병균(Phytophthora capsici), 고추탄저병균(Glomerella cingulate), 사과점무늬 낙엽병균(Alternaria mali)과 벼도열병균(Magnaporthe grisea)에서 광범위하게 살균효과를 나타내었다. Thyme 오일의 주성분을 GC/MS로 분석한 결과 thymol, carvacrol, borneol, linalool과 p-cymene임을 확인하였다. 이 중 thymol과 carvacrol이 높은 살균활성을 나타내었다. 한편, 식물병원균에 대한 살균활성관련 작용기작을 실험한 결과, 잿빛곰팡이병균(Botrytis cinerea), 잎집무늬마름병균(Rhizoctonia solani)과 사과점무늬낙엽병균(Alternaria mali)의 포자발아를 억제하는 것으로 나타났다. Thymol과 carvacrol은 in vivo에서 잿빛곰팡이병균(Botrytis cinerea)과 잎집무늬마름병균(Rhizoctonia solani)에 대하여 높은 예방효과를 나타내었으며, thymol, carvacrol의 유사구조를 갖는 alkylphenol계 화합물들도 살균활성이 있음을 검정하였다.

• 한국자원식물학회지
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• 제30권4호
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• pp.343-351
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• 2017

401종의 식물에서 얻은 메탄올 추출물 662개를 식물 병원성 곰팡이[딸기잿빛곰팡이병균(Botrytis sp.), 고추탄저병균(Colletotrichum sp.), 작약점무늬병균(Alternaria sp.) 및 작약검은뿌리썩음병균(Cylindrocarpon sp.)]에 대한 분생포자의 발아억제 활성을 microdilution assay로 측정하였다. 검정에 사용한 추출물 중에서 36종의 추출물이 1종 이상의 곰팡이에 대하여 억제활성을 보였다. 짚신나물, 고본, 족도리풀, 일천궁, 백선 및 목향의 뿌리, 능소화의 잎가지, 감초의 지상부, 뽕나무의 가지 추출물은 식물의 지상부 조직에서 발병하는 균(Botrytis sp., Colletotrichum sp. 그리고 Alternaria sp.)과 뿌리에 발병하는 균(Cylindrocarpon sp.)의 포자발아를 모두 억제하는 항균활성을 보여 주어 이들 추출물의 항균범위가 넓은 것으로 나타났다. 각각의 곰팡이 대한 추출물의 억제활성을 보면, 뽕나무의 가지와 고삼의 뿌리 추출물은 1,250 mg/L에서 딸기잿빛곰팡이병균의 포자발아를 완전히 억제하였다. 고추탄저병균의 포자발아억제에 가장 강한 추출물은 홀아비꽃대의 뿌리였으며, $1,250{\mu}g/ml$에서 완전히 억제하였다. 작약점무늬병균에 가장 강한 억제활성을 나타낸 추출물은 감초의 지상부였으며, $625{\mu}g/ml$에서 포자의 발아를 100% 억제하였고, 새모래덩굴의 뿌리와 뽕나무 가지 추출물은 $1,250{\mu}g/ml$에서 억제하였다. 작약검은뿌리썩음병균에 가장 강한 억제활성을 나타낸 추출물은 감초의 지상부와 목향의 뿌리였으며, $1,250{\mu}g/ml$에서 포자발아를 억제하였다.

• 한국식물병리학회지
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• 제13권1호
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• pp.57-62
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• 1997

This experiment was conducted to test the control effect of methanol extracts of 10 medicinal plants on apple storage diseases caused by Botryosphaeria berengeriana, Glomerella cingulata and Penicillium expansum. Out of the 10 medicinal plants, methanol extracts of Coptis japonica and Anemarrhena asphodeloides inhibited effectively the mycelial growth of B. berengeriana, G. cingulata and P. expansum in vitro, for which the inhibition ratios of the two plant extracts were 100.0% and 89.3%, 73.7% and 94.1%, and 100.0% and 51.6%, respectively. Spore germination of the three fungi was inhibited 100% only by C. japonica extract, but only P. expansum was inhibited 100% by A. asphodeloides extract. No lesion was formed y the fungi at 5$^{\circ}C$ up to 2 weeks after inoculation. Lesion sizes produced by the three fungi at the temperature ranges of 1$0^{\circ}C$ to $25^{\circ}C$ and infection of B. berengeriana and G. cingulata were inhibited by C. japonica extract, but not by A. asphodeloides extract, while no lesion was formed by the fungi at 5$^{\circ}C$. Infections of the fungi on apples were somewhat stimulated by A. asphodeloides extract.

• Mycobiology
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• 제48권6호
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• pp.484-494
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• 2020

Oak wilt disease caused by Raffaelea quercus-mongolicae has emerged obviously in Korea. We selected antifungal isolates against R. quercus-mongolicae among 368 endophytic fungal isolates from different parts of oak and pine trees. The experiment was conducted in the primary and secondary screenings by dual culture test. The antifungal activity of the selected isolates was assessed in culture filtrate test based on the inhibition rates in mycelial growth, sporulation, and spore germination of oak wilt fungus. Five isolates, E089, E199, E282, E409 and E415, showed strong antifungal activity in culture filtrate test, and their antifungal activity decreased on the culture media supplemented with heated culture filtrate. Higher mycelial growth inhibitions on the unheated media were recorded in E409 (Colletotrichum acutatum), E089 (Daldinia childiae), E415 (Alternaria alternata) and E199 (Daldinia childiae) with the inhibition rates of 79.0%, 70.1%, 68.9% and 64.5%, respectively. These isolates also had the higher sporulation inhibitions on unheated media with the rates of 96.8%, 84.2%, 82.8% and 80.5%, respectively. The spore germination of the oak wilt fungus was completely inhibited by E282 (Nectria balsamea) on both unheated and heated media. These results showed that a higher number of potent antifungal isolates against oak wilt fungus was isolated from the petiole compared to the other parts. This study could contribute to the development of biological control approaches for the management of oak wilt disease caused by R. quercus-mongolicae.

• BMB Reports
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• 제42권1호
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• pp.47-52
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• 2009

Alanine racemase catalyzes the interconversion of L-alanine and D-alanine and plays a crucial role in spore germination and cell wall biosynthesis. In this study, alanine racemase produced by Bacillus anthracis was expressed and purified as a monomer in Escherichia coli and the importance of lysine 41 in the cofactor binding octapeptide and tyrosine 270 in catalysis was evaluated. The native enzyme exhibited an apparent $K_m$ of 3 mM for L-alanine, and a $V_{max}$ of $295\;{\mu}moles/min/mg$, with the optimum activity occurring at $37^{\circ}C$ and a pH of 8-9. The activity observed in the absence of exogenous pyridoxal 5'-phosphate suggested that the cofactor is bound to the enzyme. Additionally, the UV-visible absorption spectra indicated that the activity was pH independece, of VV-visible absorption spectra suggests that the bound PLP exists as a protonated Schiff's base. Furthermore, the loss of activity observed in the apoenzyme suggested that bound PLP is required for catalysis. Finally, the enzyme followed non-competitive and mixed inhibition kinetics for hydroxylamine and propionate with a $K_i$of $160\;{\mu}M$ and 30 mM, respectively.

• 한국식물병리학회지
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• 제10권2호
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• pp.119-122
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• 1994

Effects of organophosphorus fungicides on cutinase activity from Glomerella cingulata causing apple anthracnose and infection of apple were investigated. Diisoprophylfluorophosphate (DFP) inhibited the enzyme activity indicating that catalysis involves an active serine. In inhibition of the enzyme activity by organophosphorus fungicides, I50 (molar concentration of fungicide at which the enzyme activity is inhibited 50%) of Hinosan and Kitazin P were 26.3 $\mu$M and 427.7 $\mu$M, respectively. At concentration of 10-3 M DFP and organophosphorus fungicides, the infection of G. cingulata was inhibited to 5% in comparison with 15% infection at the unwounded healthy control, but increased to 30% when added with 1 mg/ml of cutinase. Mycelial growth was 36 mm in colony diameter on the medium added with 10-4M of hinosan in comparison with 90 mm of the untreated control, but was 90 mm on the medium added with 10-4M of kitazin P showing lower inhibition than hinosan. The spore germination was more than 60% at all the concentrations of both fungicides.

• Mycobiology
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• 제30권1호
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• pp.55-56
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• 2002

The 4',7-dimethoxyisoflavone was isolated from the leaves of Albizzia lebbeck for the first time. This flavonoid showed antifungal activity against some plant pathogenic fungi tested in vitro, e.g., Alternaria melongenae, A. brassicicola, A. brassicae, Curvularia maculans, C. pallescens, C. lunata, Curvularia species, Colletotrichum species, Helminthosporium penniseti and H. speciferum. The sensitivity of different fungi to this chemical varied considerably. A. brassicae was most sensitive as complete inhibition of germination was observed in all the concentrations(100 to 1000 ppm) of the chemical. Similar effect on H. speciferum and Curvularia species was also recorded at 500 ppm, whereas H. penniseti did not germinate at 250 ppm. A. melongenae and A. brassicicola also did not germinate at 1000 ppm while 750 ppm was inhibitory to C. lunata and C. maculans. Germination in almost all fungi was significantly inhibited at each concentration in comparison to control except Curvularia sp. and H. speciferum. Use of 4',7-dimethoxyisoflavone to control some plant diseases under field conditions has been suggested.

• 미생물학회지
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• 제48권4호
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• pp.325-327
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• 2012

먹물버섯 C. congregatus의 자가분해되는 자실체 조직에서 발현되는 chitinase (Chi2)가 식물병원성 균류인 A. alternata와 F. graminearum를 대상으로 고체배지와 액체배지에서 포자의 발아 및 균사 생장에 대하여 보이는 억제효과 실험을 수행하였다. 액체배지에서 $50{\mu}g/ml$의 Chi2 농도에서 A. alternata의 포자 발아가 90% 이상 억제되었고, $70{\mu}g/ml$의 농도에서 실험균류 모두 생장이 억제되었다. 고체배지에서 하루에 $6{\mu}g$씩 2회 더한 Chi2에 의하여 F. graminearum 균사 생장이 억제됨을 확인하였고, 이때 균사의 branching이 상대적으로 감소하였다.

• 한국균학회지
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• 제22권1호
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• pp.50-61
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• 1994

토양으로부터 분리한 380개체의 균주 중 Fusarium solani에 대해 길항능력이 있는 방선균 및 세균 42개 균주로부터 길항작용이 큰 균주로 CHA 1과 5-PFHR 6을 공시하여 동정한 결과 각각 Promicromonospora sp.와 Pseudomonas pseudoalcaligenes로 동정되었다. PDA 평판배지상에서 두 균주는 모두 F. solani의 저해작용으로 균사의 길이 생장억제, 비정상적인 균사의 분지, 세포벽 분해에 의한 돌기형성 등이 관찰되었다. F. solani 포자발아에 미치는 길항균주의 배양여과액의 작용으로 감자즙액 배지나 nutrient broth에 배양한 여과액은 포자발아 억제력이 높아 14.3%의 낮은 발아율을 보였으며, 토양침출액 단독 또는 두 영양배지에 토양침출액을 첨가하여 준비한 배양 여과액에서의 발아율은 85% 이상으로 포자발아가 촉진되었으나 S-PFHR 6의 경우 두 영양배지에 소량의 토양침출액을 첨가한 배앙여과액에서 4%의 발아율을 보였다. 자연토양에서 대형포자는 19.4%, 후막포자는 17.7%가 발아하였으나 증기살균 토양에서의 발아율은 79.7% 이상으로 증가하였다. 자연토양에 공시길항균 CHA 1과 S-PFHR 6의 균체를 처리하면 토양 정균력이 증가되어 F. solani의 대형 포자 발아율은 각 처리구에서 각각 14.7%, 11.7%로 감소하였다. 길항균을 처리한 토양에 glucose와 asparagine을 처리하면 토양의 정균력이 점차 해소되어 대형포자의 발아율은 48.0% 이상으로 증가하였다. 공시균주의 2차 대사산물에 의한 길항작용으로 두 균주의 배양여과액을 토양에 처리한 경우 CHA 1의 배앙여과액을 처리한 토양에서의 F. solani 대형포자의 발아율은 9.3%, 5-PFHR 6 처리구에서의 발아율은 38.0%가 되었다. F. solani의 후막포자는 공시길한균주의 균체나 배양여과액 처리구에서의 발아율이 자연토양에서의 발아율보다 낮았으며 이러한 현상은 영앙원을 첨가해 주어도 변하지 않았다.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1103-1108
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• 2016

Yam anthracnose caused by Colletotrichum gloeosporioides (C.g) is the most devastating disease of yam (Dioscorea sp.). In the present study, we evaluated the culture filtrate extract (CFE) of azalomycin-producing Streptomyces malaysiensis strain MJM1968 for the control of yam anthracnose. MJM1968 showed strong antagonistic activity against C.g in vitro. Furthermore, the MJM1968 CFE was tested for inhibition of spore germination in C.g, where it completely inhibited spore germination at a concentration of 50 μg/ml. To assess the in planta efficacy of the CFE and spores of MJM1968 against C.g, a detached leaf bioassay was conducted, which showed both the treatments suppressed anthracnose development on detached yam leaves. Furthermore, a greenhouse study was conducted to evaluate the CFE from MJM1968 as a fungicide for the control of yam anthracnose. The CFE non-treated plants showed a disease severity of >92% after 90 days of artificial inoculation with C.g, whereas the disease severity of CFE-treated and benomyl-treated yam plants was reduced to 26% and 15%, respectively, after 90 days. Analysis of the yam tubers from the CFE-treated and non-treated groups showed that tubers from the CFE-treated plants were larger than that of non-treated plants, which produced abnormal smaller tubers typical of anthracnose. This study demonstrated the utility of the CFE from S. malaysiensis strain MJM1968 as a biofungicide for the control of yam anthracnose.