• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.5 no.2
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• pp.50-54
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• 2024

On August 21, 2023, the National Institute of Ecology reported the sighting of an invasive slug resembling Limax maximus Linnaeus, 1758. near Bambat Tree Frog Park, Suwon-si, Korea. This slug is known for its aggressiveness. Specimens were collected around the park and from nearby farms. Through barcoding analysis and sequence comparison, it was identified as L. maximus, confirming its presence in Republic of Korea, alongside two previously identified Limax species, Limax flavus Linnaeus, 1758 and Lehmannia marginatus O. F. Müller, 1774. This study represents the first documented report of L. maximus in the country.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.377-383
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• 2009

This study was conducted to investigate the total phenol contents, antioxidative activities and antibacterial activities of twenty species of entomopathogenic fungi. The total phenol content was highest in Aspergillus flavus ($553.0{\pm}52.15{\mu}g/g$) and A. parasiticus ($529.9{\pm}60.10{\mu}g/g$). On the other hand those in other strains were within the range of $26.6{\sim}121.9{\mu}g/g$. The antioxdative activity was shown in the most of strains and the highest DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging activity was observed in A. flavus ($90.9{\pm}2.90%$) and A. parasiticus ($77.9{\pm}4.13%$). This result indicated that the antioxidative activities were very correlated with the total phenol contents. The antibacterial activitiy was found in the every tested pathogenic bacteria. Especially, the antibacterial activity was strongest against Listeria monocytogenes and Escherchia coli.

• Toxicological Research
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• v.32 no.1
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• pp.81-87
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• 2016

Aflatoxin B1 (AFB1) is produced by Aspergillus flavus growing in feedstuffs. Early detection of maize contamination by aflatoxigenic fungi is advantageous since aflatoxins exert adverse health effects. In this study, we report the development of an optimized conventional PCR for AFB1 detection and a rapid, sensitive and simple screening Real-time PCR (qPCR) with SYBR Green and two pairs of primers targeting the aflR genes which involved aflatoxin biosynthesis. AFB1 contaminated maize samples were divided into three groups by the toxin concentration. Genomic DNA was extracted from those samples. The target genes for A. flavus were tested by conventional PCR and the PCR products were analyzed by electrophoresis. A conventional PCR was carried out as nested PCR to verify the gene amplicon sizes. PCR-RFLP patterns, obtained with Hinc II and Pvu II enzyme analysis showed the differences to distinguish aflatoxin-producing fungi. However, they are not quantitative and need a separation of the products on gel and their visualization under UV light. On the other hand, qPCR facilitates the monitoring of the reaction as it progresses. It does not require post-PCR handling, which reduces the risk of cross-contamination and handling errors. It results in a much faster throughout. We found that the optimal primer annealing temperature was $65^{\circ}C$. The optimized template and primer concentration were $1.5{\mu}L\;(50ng/{\mu}L)$ and $3{\mu}L\;(10{\mu}M/{\mu}L)$ respectively. SYBR Green qPCR of four genes demonstrated amplification curves and melting peaks for tub1, afIM, afIR, and afID genes are at $88.0^{\circ}C$, $87.5^{\circ}C$, $83.5^{\circ}C$, and $89.5^{\circ}C$ respectively. Consequently, it was found that the four primers had elevated annealing temperatures, nevertheless it is desirable since it enhances the DNA binding specificity of the dye. New qPCR protocol could be employed for the determination of aflatoxin content in feedstuff samples.

• Journal of Life Science
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• v.24 no.12
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• pp.1308-1315
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• 2014

Biological control using the plant growth-promoting Rhizobacterium (PGPR) has received significant attention in recent years. PGPR has been linked with promoting growth in economically important crops, such as potatoes, tomatoes, and rice. Bacillus mojavensis KJS-3 (Moja-3), isolated from food waste, possesses antifungal properties against Aspergillus terreus, A. fumagatus, A. flavus, and Fusarium redolense, and it may have potential in the development of products for industrial applications. The main purpose of this study was to determine the effects of spraying the PGPR Bacillus mojavensis KJS-3 on the growth of altari radish (leaf number, leaf length, leaf weight, root length, and rhizome length, adjacent portion diameter, and weight) and lettuce (leaf number, length, width, and weight). Three different concentrations of the foliar spray treatment of B. mojavensis KJS-3 were applied to the altari radish and lettuce: the recommended standard concentration of $1{\times}10^9cfu/g$, half the standard concentration of $0.5{\times}10^9cfu/g$, and double the standard concentration of $2{\times}10^9cfu/g$). The B. mojavensis strain foliar spray treatment increased the growth of the leaves and roots of the altari radish and increased the growth of the lettuce leaves. For both plants, the recommended concentration of B. mojavensis KJS-3 produced better growth than half the standard concentration, and the growth was similar with the double dose. This study demonstrates positive effects of Moja-3, suggesting it may be a potential new bio-fertilizer for improving the growth of altari radish and lettuce.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.218-224
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• 2011

Lactic acid bacteria (LAB) OA18 was isolated from yogurt prepared by using Kefir Grain as a starter. The OA18 strain was a Gram-positive, cocci-type bacterium, and able to grow anaerobically with $CO_2$ production. The OA18 strain grew well on MRS broth supplemented with 50 mM arginine at $30-37^{\circ}C$ and pH of 7.0-9.0. The optimum temperature and pH for growth are $37^{\circ}C$ and pH 7.0. The isolate fermented ribose, D-glucose, cellobiose, D-trehalose, but not L-xylose, D-melibiose, and inositol. The 16S rRNA gene sequence of the isolate showed 99.8% homology with the Enterococcus faecalis 16S rRNA gene (Access no. AB012212). Based on the biochemical characteristics and 16S rRNA gene sequence analysis data, it was identified and named as E. faecalis OA18. The E. faecalis OA18 strain showed a high ornithine-producing capacity in the presence of arginine and also showed an antimicrobial activity against Streptomyces strains such as Streptomyces coelicolor subsp. Flavus, S. coeruleorubidus, S. coeruleoaurantiacus, S. coelicolor, S. coeruleoprunus. The cell growth of E. faecalis OA18 strain was maintained in MRS broth with a NaCl concentration of 0-7%.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.270-277
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• 2010

In order to manufacture Bacillus cereus-free fermented soybean products, an antimicrobial agentproducing isolate against B. cereus was obtained from 150 traditionally fermented soybean products. The morphological and biochemical tests and the phylogenetic relationship among 16S rRNA gene sequences indicated that the isolate named as the strain SCK 121057 was most closely related to Bacillus licheniformis. The B. licheniformis isolate began to produce the antimicrobial agent after 48 h of incubation. The agent was nonproteinaceous and insensitive to heat, long term storage and protease K. Electron microscopic observation indicated that the agent attacked the membrane of B. cereus, leaving the ghost cell. The isolate inhibited growth of B. subtilis, Lactobacillus brevis and various types of pathogenic strains including Escherichia coli, E. faecalis, Micrococcus luteus, Staphylococcus aureus, Aspergillus flavus, A. ochraceus, and A. parasiticus as well as B. cereus. After coinoculation of B. licheniformis SCK 121057 and B. cereus in the ratio (as the basis of CFU/g sample) of 10 to 1 on the surface of cooked soybeans, cell numbers of B. cereus had been dramatically reduced after 31 days of incubation compared to those of single inoculation of B. cereus.

• Applied Biological Chemistry
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• v.11
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• pp.89-93
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• 1969

The strains selected in the previous paper were identified according to the manual of Aspergilli by Thom and Raper, and the preparation of the crude enzymes with the strains were investigated. The fermented fodders were made with wheat bran and chaffs containing 20% wheat bran by the strains, and the feeding experiments concerned was conducted. The results obtained are as follows: 1. The selected strains were identified as below; MC-9 was a similar strain of Aspergillus niger van Tieghem, MC-10 was a similar strain of Aspergillus flavus Link, MC-53 was a similar strain of Aspergillus penicilloides Spegazzini and MC-61 was a similar strain of Aspergillus niger mut Schiemanni n. comb. 2. Percentages of crude enzymes obtained from the dried matters of the wheat bran cultures were MC-9: 2.9%, MC-10: 3.9%, MC-53: 6.4% and MC-61:2.6%. And the cellulase activity of MC-9 was the most active among the crude enzymes as the same as the filtrates of wheat bran cultures. 3. As the results of the feeding experiments, changes of body weights showed no trends to be significant as compared with the control group, and the groups of MC-9 and MC-61 showed the increasing significance with P<0.05 in egg-laying rate.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.932-941
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• 2013

This work aimed to classify Aspergillus (8 species, 28 strains) by using a secondary metabolite profile-based chemotaxonomic classification technique. Secondary metabolites were analyzed by liquid chromatography ion-trap mass spectrometry (LC-IT-MS) and multivariate statistical analysis. Most strains were generally well separated from each section. A. lentulus was discriminated from the other seven species (A. fumigatus, A. fennelliae, A. niger, A. kawachii, A. flavus, A. oryzae, and A. sojae) with partial least-squares discriminate analysis (PLS-DA) with five discriminate metabolites, including 4,6-dihydroxymellein, fumigatin, 5,8-dihydroxy-9-octadecenoic acid, cyclopiazonic acid, and neosartorin. Among them, neosartorin was identified as an A. lentulus-specific compound that showed anticancer activity, as well as antibacterial effects on Staphylococcus epidermidis. This study showed that metabolite-based chemotaxonomic classification is an effective tool for the classification of Aspergillus spp. with species-specific activity.

• Journal of Environmental Health Sciences
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• v.33 no.3
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• pp.190-194
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• 2007

Aflatoxin $B_1$ is a mycotoxin produced by Aspergillus flavus and A. parasiticus and is a human carcinogen. This study was performed to investigate reduction of growth and aflatoxin production of A. parasiticus by kimchi. A. parasiticus was grown in a modified APT broth with the juice of kimchi (at a concentration of 7%) at $28^{\circ}C$ for 9 days. Aflatoxin $B_1$ was determined by use of high performance liquid chromatography (HPLC). The addition of the juice of kimchi significantly reduced mycelial growth and aflatoxin production during the incubation period (p<0.05). Reduction of mycelial growth of A. parasiticus as the result of addition of the juice of kimchi was observed to range between 64.8 to 83.4% while reduction of aflatoxin production ranged from 62.2 to 73.0%. This study indicates that kimchi could be an effective inhibitor of aflatoxin production although mycelial growth may be permitted. More research is needed to study the inhibitory effects of the metabolites of kimchi.

• BMB Reports
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• v.42 no.5
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• pp.281-285
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• 2009

Peroxisomes play an important role in cellular defense systems and generate secondary messengers for cellular communication. Saccharomyces cerevisiae containing oleate-induced peroxisomes were subjected to buffer-soluble extraction and two chromatographic procedures, and a protein with antifungal activity was isolated. The results of MALDI-TOF analysis identified the isolated protein as peroxisomal 3-ketoacyl-CoA thiolase (ScFox3). Purified yeast ScFox3 exhibited thiolase activity that catalyzed the thiolytic cleavage of 3-ketoacyl-CoA to acetyl-CoA and acyl-CoA. ScFox3 protein inhibited various pathogenic fungal strains, with the exception of Aspergillus flavus. Using ScFox3-GFP and PTS2 signal-truncated ScFox3M-GFP, we showed that only ScFox3-GFP, with an intact PTS2 peroxisome signal sequence, was able to translocate into peroxisomes. Yeast ScFox3 is a natural antifungal agent found in peroxisomes.