• The Plant Pathology Journal
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• 제38권6호
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• pp.629-636
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• 2022

Colletotrichum species is known as the major causal pathogen of red pepper anthracnose in Korea and various groups of fungicides are registered for the management of the disease. However, the consistent use of fungicides has resulted in the development of resistance in many red pepper-growing areas of Korea. Effective management of the occurrence of fungicide resistance depends on constant monitoring and early detection. Thus, in this study, various methods such as agar dilution method (ADM), gene sequencing, allele-specific polymerase chain reaction (PCR), and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were applied for the detection of benzimidazole resistance among 24 isolates of Colletotrichum acutatum s. lat. and Colletotrichum gloeosporioides s. lat. The result of the ADM showed that C. gloeosporioides s. lat. was classified into sensitive and resistant isolates to benomyl while C. acutatum s. lat. was insensitive at ≥1 ㎍/ml of benomyl. The sequence analysis of the β-tubulin gene showed the presence of a single nucleotide mutation at the 198th amino acid position of five isolates (16CACY14, 16CAYY19, 15HN5, 15KJ1, and 16CAYY7) of C. gloeosporioides s. lat. Allele-specific PCR and PCR-RFLP were used to detect point mutation at 198th amino acid position and this was done within a day unlike ADM which usually takes more than one week and thus saving time and resources that are essential in the fungicide resistance management in the field. Therefore, the molecular techniques established in this study can warrant early detection of benzimidazole fungicide resistance for the adoption of management strategies that can prevent yield losses among farmers.

• Journal of Microbiology and Biotechnology
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• 제33권9호
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• pp.1238-1249
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• 2023

In this study, we sought to investigate the production and optimization of biosurfactants by soil fungi isolated from petroleum oil-contaminated soil in Saudi Arabia. Forty-four fungal isolates were isolated from ten petroleum oil-contaminated soil samples. All isolates were identified using the internal transcribed spacer (ITS) region, and biosurfactant screening showed that thirty-nine of the isolates were positive. Aspergillus niger SA1 was the highest biosurfactant producer, demonstrating surface tension, drop collapsing, oil displacement, and an emulsification index (E₂₄) of 35.8 mN/m, 0.55 cm, 6.7 cm, and 70%, respectively. This isolate was therefore selected for biosurfactant optimization using the Fit Group model. The biosurfactant yield was increased 1.22 times higher than in the nonoptimized medium (8.02 g/l) under conditions of pH 6, temperature 35℃, waste frying oil (5.5 g), agitation rate of 200 rpm, and an incubation period of 7 days. Model significance and fitness analysis had an RMSE score of 0.852 and a p-value of 0.0016. The biosurfactant activities were surface tension (35.8 mN/m), drop collapsing (0.7 cm), oil displacement (4.5 cm), and E₂₄ (65.0%). The time course of biosurfactant production was a growth-associated phase. The main outputs of the mathematical model for biomass yield were Yx/s (1.18), and µ_max (0.0306) for biosurfactant yield was Y_p/s (1.87) and Y_p/x (2.51); for waste frying oil consumption the So was 55 g/l, and Ke was 2.56. To verify the model's accuracy, percentage errors between biomass and biosurfactant yields were determined by experimental work and calculated using model equations. The average error of biomass yield was 2.68%, and the average error percentage of biosurfactant yield was 3.39%.

• 한국도서관정보학회지
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• 제35권4호
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• pp.469-489
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• 2004

시대구분(연대범주)은 주제와 결합하여 주제의 범위를 특정 연대(시대)로 한정하는 방법으로서 분류표에 따라서 사용기법을 달리 하고 있다. CC와 UDC는 공통구분표를 통해 일관성있고 분명한 시대구분이 가능하다. DDC와 KDC는 표준구분, 역사류, 문학류에 따라 시대구분 기호를 다르게 사용하고 있다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 춘계학술대회 및 임시총회
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• pp.29-29
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• 2015

Clubroot disease is caused by the soil-born obligate plant pathogen Plasmodiophora brassicae. This pathogen can infect all cruciferous vegetables and oil crops, including Brassica rapa, B. oleracea, B. napus, and other Brassica species. Clubroot disease is now considered to be a major problem in Chinese cabbage production in China, Korea, and Japan. We collected several hundreds of P. brassicae infected galls from Korea, and isolated the single spore from the collection. For establishment of novel isolation, and mass-propagation methods for singe spore isolates of P. brassicae pathogen, we developed new filtration method using both cellulose nitrate filter and syringe filter. Accurate detection of P. brassicae pathogen in the field was done by using real-time PCR in the potential infested soil. When we tested the different pathogenicity on commercial Chinese cabbage varieties, P. brassicae from collected galls showed various morphological patterns about clubroot symptom on roots. To date, 8 CR loci have been identified in the B. rapa genome using the quantitative trait loci (QTL) mapping approach, with different resistant sources and isolates. We are trying to develop the molecular marker systems for detect all 8 CR resistant genes. Especially for the study on the interaction between pathogens and CR loci which are not well understood until now, genome wide association studies are doing using the sequenced inbred lines of Chinese cabbage to detect the novel CR genes.

• 대한수의학회지
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• 제28권1호
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• pp.115-118
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• 1988

Mating experiments were performed to, elucidate the distribution of perfect state of Microsporum gypseum complex originated from animals and soils in Korea. A total of 30 strains of M. gypseum complex, composed of 16 from animals and 14 from soils, ere mated with the tester strains of Nannizzia incurvata, N. gypsea and N. fulva. Among 30 strains of M. gypseum complex examined, 16 strains(53.3%) were N. incurvata, 13 strains(43.3%) N. gypsea and 1 strain (3.3%) N. fulva. Among 13 strains of dog isolates, 8 strains(61.5%) were N. incurvata and 5 strains(38.5%) N. gypsea. And each strain isolated from Korean native goat, monkey and albino rat was N. gypsea. Among 14 strains of soil isolates, 8 strains(57.2%) were N. incurvata, 5 strains (35.7%) N. gypsea and 1 strain(7.2%) N. fulva. And -mating type was more frequently observed than +mating type in the strains of N. incurvata and N. gypsea. By this study, N. fulva was isolated the first time in Korea.

• The Plant Pathology Journal
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• 제15권1호
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• pp.28-33
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• 1999

Phytophthora root rot of Chniese cabbage and spinach is reported for the first time in Korea. The diseases ocurred at Yangju, Seosan and Yeocheon in Korea from 1995 through 1998, mainly in lowland and submerged areas. Symptoms consisted of stunt, yellows, wilt and eventual death due to root rot. Fourteen isolates collected from naturally infected plants were all identified as P. drechsleri based on mycological characteristics. PCR-RFLP analysis of rDNA of the isolates confirmed the above result, since the restriction band patterns of the small subunit and internal transcribed spacers were identical to P. drechsleri and P. cryptogea, but distinct from closely related species of P. erythroseptica, P. cambivora, P. sojae and P. megasperma. The pathogen showed strong pathogenicity to Chinese cabbage, moderate to spinach, radish, cabbage and tomato, and weak or none to brown mustard, kale, chicory and pepper in pathogenicity tests.

• 대한수의학회지
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• 제50권4호
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• pp.279-284
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• 2010

Combination therapy of antibiotics is leading to improved efficacy or safety profiles with decrease emergence of bacterial resistance. Because of this benefit, many of antibacterial combinations have been used in veterinary practice for the past few decades. The purpose of this study was to examine the in vitro activity of an amoxicillin alone and in combination with other antibiotics against pathogenic bacteria of fish origin. Based on the fractional inhibitory concentration (FIC) index (FIC $$\leq_-$$ 0.5), a synergistic interaction was shown in combination of florfenicol with amoxicillin or cefuroxime. The combination of florfenicol and amoxillin showed higher antibacterial activity than that of florfenicol and cefuroxime. Ratio of amoxicillin and florfenicol in combination was 1 : 1, which showed the antibacterial activity against bacterial isolates of fish as compared with other ratios. A synergetic effect of the combination (amoxicillin and florfenicol) was further confirmed in the time-kill curve study. The study showed a better in vitro antibacterial activity of a 1 : 1 combination of amoxicillin and florfenicol than the individual antibacterial against bacterial isolates of fish. In conclusion, the combination of florfenicol and amoxicillin may serve as a potential antibacterial therapy in fishes infected pathogenic bacteria.

• Mycobiology
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• 제48권3호
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• pp.210-218
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• 2020

Peach (Prunus persica L.) is one of the major fruit crops in South Korea, along with apple, persimmon, and Asian pears. Peach anthracnose is a continuing threat to growers and is accountable for enormous economic loss. In July 2018, anthracnose of peach appeared at different peach orchards in Gyeongsangbuk-do region, Korea. The typical anthracnose symptoms (brown, circular, and necrotic lesions) were observed on the fruits. Anthracnose of peach was surveyed in different peach orchards of Gyeongsangbuk-do, and 20 fungal isolates from 19 diseased fruits were collected. Multigene phylogenetic analyses coupled with morphological characteristic analysis approaches were used for identifying the fungal species isolated from diseased fruits. This study confirmed three Colletotrichum species. Based on the results, Colletotrichum siamense are reported for the first time as causal agents of peach anthracnose alongside C. fructicola and C. fioriniae, which has been reported previously. Pathogenicity assays were performed for the three isolates representing all the species identified, and Koch's postulates on detached healthy peach fruits were verified. All the identified species were pathogenic on peach fruits as the typical anthracnose symptoms were reproduced. Significant variations in the virulence were observed among fungal species on peach fruit.

• 한국균학회지
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• 제30권1호
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• pp.56-60
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• 2002

1998년 병든 화본과작물, 목초, 잔디 및 야생잡초의 잎점무늬와 마름병징으로부터 Curvularia spp. 16균주를 분리하였다. 이들 균주를 균학적 특징을 기초로 동정한 결과 C. cymbopogonis, C. inaequalis, C. intermedia, C. lunata, C. lunata var. aeria, C. ovoidea, C. pallescens C. senegalensis로 동정되었다. 이중에서 C. cymbopogonis, C. lunata var. aeria, C. ovoidea, C. senegalensis는 국내에서 처음 보고되는 미기록종들이다.

• Fisheries and Aquatic Sciences
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• 제15권2호
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• pp.91-97
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• 2012

To isolate a nonylphenol (NP)-degrading bacterium, we isolated a single colony from the NP-degrading microbial consortium SW-3, which was previously isolated from an aqueous environment. Ten colonies that exhibited different cell morphologies were isolated and the strains were named SW-3-A, -B, -C, -D, -E, -F1, -F2, -G, -H, and -I. The ability of isolates to degrade NP was evaluated by kinetic analysis by the constant of NP degradation rate ($k_1$) and the half-life time of NP degradation ($t_{1/2}$). SW-3-F1, -F2, -G, and -I strains were superior at degrading NP. The $k_1$ and $t_{1/2}$ values of the four strains were sixfold higher and one-sixth lower, respectively, than those of the consortium strain. Additionally, SW-3-F1, -G, and -I strains were tested for their ability to degrade NP during coculture. NP degradation by coculture with a combination of all three strains was inferior to that of culture conducted with single isolates, suggesting that the three strains are antagonistic toward each other during NP degradation.