• Journal of agriculture & life science
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• v.46 no.3
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• pp.37-45
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• 2012

To select bacterial strains with antifungal activity against an anthracnose fungal disease causing damage severely on hot pepper, previous isolates obtained from plant root samples were screened. Among 457 isolates, IA70-5 isolate was finally selected and identified as Streptomyces padanus based on 16S rDNA sequence analysis. Strain IA70-5 is non-pigmenteous, non-mobile, and filamentous. S. padanus IA70-5 inhibited effectively the mycelium growth, spore germination, and appressorium formation of Colletotrichum acutatum in vitro. The results of this study demonstrated that IA70-5 strain, especially applied on fruit of hot pepper, decreased disease incidence 90% for pre-inoculation before pathogen treatment. Taken together, S. padanus IA70-5 strain is a promising biological control agent to control of a major fungal pepper disease, anthracnose.

• Journal of Life Science
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• v.31 no.10
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• pp.929-936
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• 2021

In the present study, we screened candidate natural compounds which possess the strong anti-proliferative effects on human colorectal HCT116 cells using the commercial natural product library (Selleckchem, L1400) based on cell viability assay. Human colorectal cancer HCT116 cells were incubated with 50 μM of each compound from the natural product library, and then cell viability was measured by MTT assay. From the first screening, five different kinds of natural products (chrysin, diosmetin, emodin, piperlongumine, and tanshinone I) were selected based on cell viability assay in HCT116 cells and commercial availability. All selected natural products significantly decreased cell viabilities in HCT116 cells, whereas pro-apoptotic protein NAG-1 is strongly induced by chrysin or emodin treatment. Chrysin and emodin decreased cell viability in a dose-dependent manner. Moreover, chrysin and emodin increased the expression of pro-apoptotic NAG-1 protein in a dose- and time-dependent manner. In addition, PARP cleavage induced by chrysin or emodin was recovered in part by the transfection of NAG-1 siRNA indicating that NAG-1 may be one of the genes responsible for apoptosis induced by chrysin or emodin. Overall, our findings may provide basic screening data on natural products which possess anti-proliferative activities and may help to understand the molecular mechanisms of anti-proliferative and pro-apoptotic activities mediated by chrysin and emodin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.382-388
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• 2019

Streptococcosis caused by Streptococcus parauberis is a very important disease in farmed olive flounder Paralichthys olivaceus. For most fish pathogens, including S. parauberis, there are no analytical criteria to distinguish antibioticsusceptible strains from antibiotic-resistant strains. In this study, epidemiological cut-off ($CO_{WT}$) values were generated to classify 75 strains of S. parauberis isolated from 1999 to 2018 as wild type (WT) and non-wild type (NWT) using disc diffusion data and normalized resistance interpretation (NRI) analysis. The susceptibility of the isolates to 16 antibiotics was evaluated using CLSI guideline M42-A. The wild-type cut-off values for amoxicillin, erythromycin, oxytetracycline, and florfenicol for S. parauberis were ${\geq}35$, 31, 28, and 27 mm, respectively. The NWT ratios of S. parauberis strains to treatment with GEN, FFC, ENR, SXT, EFT, VAN, and CHL were 17% or less, indicating that these antibiotics may be used to treat streptococcosis caused by S. parauberis. For recent S. parauberis isolates, the NWT ratios for AMX, ERY, OTC and FFC are much higher than for strains isolated from 1999-2007. The $CO_{WT}$ data from this study will assist aquatic animal disease professionals in prescribing appropriate antibiotics for the treatment of streptococcosis caused by S. parauberis, which will help reduce the misuse and abuse of antibiotics in the aquaculture sector.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.127-132
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• 2019

This study investigated the quality of Jeungpyun based on variety, milling method and fermentation time. Rice flour (wet-milled Samkwang and dry-milled Seolgaeng) was used for these experiments. The expansion ratios of wet-milled Samkwang and dry-milled Seolgaeng after 6 h of fermentation showed similar values of 160.66 and 159.52%, respectively, while the specific volume was found to be 1.12 mL/g for both. Hardness values of 475.57 g in dry-milled Seolgaeng and 550.40 g in wet-milled Samkwang were determined to be the lowest values after 6 h of fermentation. Numerous pores were found in wet-milled Samkwang, whereas large-sized pores were found in dry-milled Seolgaeng. Thus, these results show no significant difference between the quality of Jeungpyun produced using dry-milled Seolgaeng or wet-milled Samkwang rice flours. However, dry- milled Seolgaeng without the wet-milled process is considered more suitable for Jeungpyun production.

• Journal of Life Science
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• v.29 no.10
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• pp.1111-1119
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• 2019

Prunus mume, known as maesil in Korea, has been widely cultivated in East Asia and used as medication and food. However, because most of the previous studies concerning P. mume had been investigated its under extract state, detailed studies are still required for its extensive utilization. In this study, we evaluated the antioxidant and ${\alpha}-glucosidase$ inhibitory activities of solvent fractions of P. mume ethanol extracts. The ethyl acetate fraction showed higher DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power, and hydrogen peroxide scavenging activity than other fractions. The DPPH radical scavenging activities of ethyl acetate fraction was 67.79%; ABTS radical scavenging activity was 60.03%; reducing power ($OD_{670}$) was 1.26; and hydrogen peroxide scavenging activity was 93.18% at $500{\mu}g/ml$. Also, the ethyl acetate and methanol fraction showed effective levels of ${\alpha}-glucosidase$ inhibition activity (69.25% and 72.29% at $500{\mu}g/ml$). Total polyphenol contents and total flavonoid contents of the ethyl acetate fraction were 88.28 mg/g (gallic acid equivalent) and 70.38 mg/g (quercetin equivalent), respectively. These results suggest that the physiological activities of the ethyl acetate fraction are associated with its polyphenol and flavonoid contents. Therefore, this study can be used as basic data for developing natural antioxidants and potential functional material using P. mume.

• Journal of Life Science
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• v.29 no.5
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• pp.564-569
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• 2019

Heavy drinking disrupts the nervous system by activation of GABA receptors and inhibition of glutamate receptors, thereby preventing short-term memory formation. Degradation of cognition by alcohol induces blackouts, and it can lead to alcoholic dementia if repeated. Therefore, drugs need to be developed to prevent alcohol-induced blackout. In this study, we confirmed the effect of an ethanol extract of Cassia obtusifolia seeds (COE) on alcohol-induced memory impairment. The effects of COE and ethanol on cognitive functions mice were examined using the passive avoidance and Y-maze tests. The manner in which alcohol affects long-term potentiation (LTP) in relation to the learning and memory was confirmed by electrophysiology performed on mouse hippocampal slices. We also measured N-methyl-D-aspartate (NMDA) receptor-mediated field excitatory synapses (fEPSPs), which have a known association with cognitive impairment caused by ethanol. Ethanol caused memory impairments in passive avoidance and Y-maze tests. COE prevented these ethanol-induced memory impairments in these tests. Ethanol also blocked LTP induction in the mouse hippocampus, and COE prevented this ethanol-induced LTP deficit. Ethanol decreased NMDA receptor-mediated fEPSPs in the mouse hippocampus, and this decrease was prevented by COE. These results suggest that COE might be useful in preventing alcohol-induced neurological dysfunctions, including blackouts.

• Journal of Apiculture
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• v.34 no.1
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• pp.15-26
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• 2019

Tracheal mite (Acarapis woodi) is an internal parasite that is parasitic on the bronchus of adult bees and sucks fluid from the trachea. Since its first report by Rennie, it has been spread throughout Europe and in some Asian regions, with adjacent Japan and China reported in 2011 and 2012, respectively. Korea detected specific genes of A. woodi in 2015, but only one of 99 samples has been identified and the being of A. woodi has not been confirmed. In this study, we established a specific nested PCR method to confirm for detecting low-copy number of A. woodi-specific gene in bee samples. As a result, A. woodi-specific COI gene was amplified in 15 of 23 samples, and they were judged positive by melting point analysis and sequencing analysis. Although we could not observe the existence of the mites in bees, our results suggest that tracheal mit might exist in nature.

• Journal of Food Hygiene and Safety
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• v.35 no.6
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• pp.521-534
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• 2020

Paralytic shellfish poisoning (PSP) occurs when saxitoxin (STX), which is produced by harmful algae (dinoflagellates) and then accumulated in bivalve shellfish by filter-feeding, is consumed by humans. With recent advances in analysis technology, it has been reported that dinoflagellates also produce a variety of analogues such as the gonyautoxin (GTX) group and the N-sulfo-carbamoyl toxin (C toxin) group, in addition to STX. Accordingly, CODEX and the EFSA are stepping forward to manage STX and analogues as STX groups requiring safety management. In Korea, the occurrence of dinoflagellates producing STX analogues has already been reported, and contamination of analogues (GTX group, C toxin group) in live mussels has also been reported. In this study, in order to provide the basis for systematic monitoring and safety management of STX and analogues, their physicochemical characteristics, occurrence of dinoflagellates, toxicity and toxic equivalency factor, analytical method and occurrence were widely reviewed. This review is expected to contribute to strengthening the safety management of STX and its analogues.

• Research in Plant Disease
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• v.29 no.4
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• pp.363-376
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• 2023

Alternaria black spots or blights in cruciferous crops have been devastating diseases worldwide and led to economic losses in broccoli, Chinese cabbage, kale, radish, rapeseed, etc. These diseases are caused by different Alternaria spp., including A. brassicae, A. brassicicola and A. raphani transmitted from infected seeds or insect vectors. Efforts to excavate disease resistance traits of cruciferous crops against Alternaria black spots or blights have been demonstrated. Genetic resource of disease resistance was investigated in the wild relatives of cruciferous crops, and different cultivars were screened under different inoculation conditions. Development of the disease-resistant lines against Alternaria black spots or blights was also tried via genetic transformation of the cruciferous crops using diverse plant defence-associated genes. Plant immunity activated by pre-treatment with chemicals, i. e. β-amino-n-butyric acid and melatonin, was suggested for reducing Alternaria black spots or blights in cruciferous crops. The disease resistance traits have also been evaluated in model plant Arabidopsis originating from different habitats. Various plant immunity-related mutants showing different disease responses from wild-type Arabidopsis provided valuable information for managing Alternaria black spots or blights in cruciferous crops. In particular, redox regulation and antioxidant responses altered in the Alternaria-infected mutants were discussed in this review.

• Korean journal of applied entomology
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• v.62 no.2
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• pp.69-78
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• 2023

The currently implemented Positive List System, sales manager training, and pesticide sales record systems focus on the safety of determined pesticide use, but the proposed agrochemical pharmacist (AP) system aims accurate diagnosis and reasonable prescription. In this study, 81% of famers claimed expert assistance for purchasing and applying pesticides, and 42~86% of sales managers insisted on the strengthening expertise in diagnosis and prescription. In the institutionalization of AP, a special implementation guideline is essential to embrace the present sales managers with long experience. Sales managers of commercial and agricultural cooperatives recognize the qualifications of agrochemical pharmacists as a strategy to differentiate themselves from competitors, and increase sales through market positioning of "pesticides prescribed by trustworthy agrochemical pharmacists", not sales managers anymore.