• Microbiology and Biotechnology Letters
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• v.10 no.1
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• pp.33-37
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• 1982

The work has been carried out for the development of antifungal antibiotics possessing curative effect in the control of sheath blight disease of rice plant. Soil samples were collected from over 1600 spots throughout the country. More than 1300 specimens which seem to be the genus Streptomyces were isolated from the soil samples. Screening procedures consist of respective processes by four steps. Those are growth inhibition test in liquid culture, paper disk method, dendroid test and green house test. 102 isolates appeared to be active against Pellicularia sasakii when all specimens isolated were examined by the first growth inhibition test. Finally a strain of Streptomyces forming strong antifungal substances against P. sasakii was selected from a soil sample of Mt. Soyo, Kyeongi Province. Antifungal substances formed by the strain were isolated and purified from the culture broth and examined for antimicrobial activities as to be specific against fungi but not active on bacterial growth.

• Mycobiology
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• v.43 no.3
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• pp.333-338
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• 2015

In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1035-1045
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• 2022

The purpose of this study is to examine whether spraying an anti-microbial agent into the slurry pit will reduce the noxious odor substances from piggery barns. For this, a total of 200 crossbred ([Landrace × Yorkshire] × Duroc) growing pigs with an initial average body weight (BW) of 23.58 ± 1.47 kg were selected and housed in two different rooms, i.e. control (CON) and treatment (TRT). Each room has 100 pigs (60 gilts and 40 borrows). For a period of 42 days, all pigs were fed with corn-soybean meal-based basal diet. Later the noxious odor substances were measured by the following methods. First, fecal samples were randomly collected and stored in sealed and unsealed containers, and sprayed with the non-anti-microbial agent (NAMA) (saline water) and multi-bacterial spraying (MBS) agent (200 :1, mixing ratio-fecal sample : probiotic), Second, the slurry pit of CON and TRT rooms were directly sprayed with NAMA and MBS, respectively. The fecal sample that was stored in sealed and un-sealed containers and sprayed with MBS significantly reduced NH₃ and CO₂ concentration at the end of day 7. However, at the end of day 42, the fecal sample showed a lower H₂S, methyl mercaptans, acetic acid, and CO₂ concentration compared to the unsealed container. Moreover, at the end of days 7, 14, 21, 28, 35, and 42 compared to the CON room and TRT room slurry pit emits lower concentrations of NH₃, acetic acid, H₂S, and methyl mercaptans, and CO₂ into the atmosphere. Based on the current findings, we infer that spraying anti-microbial agents on pig dung would be one of the better approaches to suppress the odor emission from the barn in the future.

• ALGAE
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• v.37 no.2
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• pp.175-183
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• 2022

Polar microorganisms produce physiologically active substances to adapt to harsh environments, and these substances can be used as biomedical compounds. The green microalga Micractinium variabile KSF0031, which was isolated from Antarctica, produced phytol, a natural antimicrobial agent. Furthermore, several polyunsaturated fatty acids (PUFAs), including omega-3, exhibit antioxidant properties. Here statistical methods (Plackett-Burman design and Box-Behnken design) were used to optimize the culture medium of KSF0031 to improve biomass production, and K₂HPO₄, MgSO₄·7H ₂O, and ammonium ferric citrate green (AFCg) were selected as significant components of the culture medium. Changes in the concentration of K₂HPO₄ and MgSO₄·7H ₂O as positive factors and AFCg as a negative factor affected cell growth to a remarkable degree. The biomass production in a 100 L culture using the optimized medium for 24 d at 18℃ was improved by 37.5% compared to that obtained using the original BG-11 medium. The quantities of PUFAs and phytol obtained were 13 mg g^-1 dry cell weight (DCW) and 10.98 mg g^-1 DCW, which represent improved yields of 11.70% and 48.78%, respectively. The results of this study could contribute to an improved production of phytol and fatty acids from Antarctic microalgae in the biomedical industry.

• International journal of advanced smart convergence
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• v.13 no.1
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• pp.194-200
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• 2024

In the past, antibiotics and antimicrobial substances have been used for the purpose of promoting the growth of livestock or treating livestock, but various problems such as the presence of livestock products or resistant bacteria have emerged. Recently, regulations on the use of antibiotics have been strengthened worldwide, and probiotics are attracting attention as an alternative. Probiotic microorganisms have already been used for human use, such as intestinal abnormal fermentation, diarrhea, and indigestion. In livestock, beneficial microorganisms are increasing in use for the purpose of improving productivity, such as promoting livestock development and preventing diarrhea. Therefore, it is advisable to understand livestock probiotics in deeper and think about effective uses. The role of probiotics in the livestock sector is made with microorganisms themselves, so it is a substance that promotes livestock growth and improves feed efficiency by settling in the intestines of livestock, suppressing the growth of other harmful microorganisms, helping digestion and absorption of ingested feed, and helping to synthesize other nutrients. There is a need for a probiotic that suppresses intestinal bacteria by supplying probiotics used as a means to minimize the effects of stress in livestock management, thereby suppressing disease outbreaks by maintaining beneficial microorganisms and suppressing pathogenic microorganisms. The purpose of this paper is to develop a brand of feed additive probiotics to improve health conditions due to increased feed intake, improve the efficiency of use of feed nutrients, inhibit the decomposition and production of toxic substances, increase immunity, reduce odor in livestock, and improve the environment. We investigated and analyzed feed additive probiotics already on the market, and developed the naming and logo of suitable feed additive probiotic brands in livestock. We hoped that the newly developed product will be used in the field and help solve problems in the livestock field.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.190-197
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• 2010

To develop the safe and natural antimicrobial agents, the 68 ethanol extracts from the 61 different kinds of oriental herbal medicine were prepared and their antimicrobial activities were evaluated. The herbal medicine used were from China (46 kinds), South Korea (14 kinds), North Korea (5 kinds) and Vietnam (3 kinds), respectively, and the root (27 species) was popular part in this study. The average water content and extraction ratio for ethanol were 7.10% and 6.75%, respectively. Determination of antimicrobial activity by disc-diffusion assay at 0.5 mg/disc concentration showed that the extract of Angelica tenuissima Nakai (china), Illicium verum, Junci medulla, Rhus javanica L., Salvia miltiorrhiza Bunge and Syzygium aromaticum has strong antimicrobial activities against different food spoilage and pathogenic bacteria and fungi. Determination of MIC and MBC/MFC further showed that the extract of Syzygium aromaticum has MIC of 1.25 mg/mL and MBC/MFC of 1.25~5.00 mg/mL against Listeria monocytogenes, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, Salmonella typhimurium, Proteus vulgaris, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Saccharomyces cerevisiae. And, the extract of Junci medulla, Rhus javanica L. and Salvia miltiorrhiza Bunge showed strong antibacterial activities with MIC of 0.08~0.63 mg/mL and MBC/MFC of 0.08~2.50 mg/mL against the tested bacteria except E. coli and P. aeruginosa. In a while, the results of hemolytic activity of 68 different herbal extracts against human red blood cells showed that the extract of Angelica tenuissima Nakai has hemolytic activity at 0.5 mg/mL concentration. Therefore, Illicium verum, Junci medulla, Rhus javanica L., Salvia miltiorrhiza Bunge and Syzygium aromaticum were finally selected for natural antimicrobial resources. Further research on active substances and the mode of action of the selected herbal medicine is necessary.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.310-314
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• 2006

Allium fistulosum L. (Welsh onion) is a perennial herb that is widely cultivated throughout the world, especially in China, Japan and Korea. Although, various activities were reported, little is known about antimicrobial activity of A. fistulosum L.. In this study, strong antimicrobial substances, fistuloside A, B, and C were isolated from the edible parts of A. fistulosum L. and their antimicrobial activity was evaluated with pathogenic- or food-spoilage microorganism based on disk-diffusion assay, minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) determination. Fistuloside A and fistuloside C showed strong antifungal activity and anti-Proteus activity, while fistuloside B is effective to only fungi. The fistuloside C showed a prominent antifungal activity with $3.1{\sim}6.2{\mu}g/ml$ of MIC and MFC. Our results indicated that fistuloside C has a prominent antifungal activity and support the use of A. fistulosum to treat microbial infection.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.274-282
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• 2002

The ethanol extract and n-hexane fraction from Hypericum ascyron L. showed strong growth inhibition at 25 ppm on 5 strains of Listeria monocytogenes for 72 hr at $32^{\circ}C$. The purified substance, H2-5-2 fraction, was isolated by silica gel column and preparative thin layer chromatography from n-hexane fraction of Hypericum ascyron L. The H2-5-2 fraction showed a strong bacteriostatic activity on 5 strains of L. monocytogenes at 10 ppm in tryptic soy broth, and the viable cell was reduced 1 log cycle compared to initial cell number. The n-hexane fraction of Hypericum ascyron L. showed strong growth inhibition at 25 ppm on Bacillus cereus and Staphylococcus aureus, and at 50 ppm on Vibrio parahaemolyticus for 72 hr. The purified antimicrobial substance, the H2-5-2 fraction, was assumed as high unsaturated sterol by $^1H-NMR$ and $^{13}C-NMR$. On application test using minced Alaska pollack and ground beef, the n-hexane fraction of Hypericum ascyron L. at the level of 250 ppm was applied at $32^{\circ}C$ and $5^{\circ}C$. At $32^{\circ}C$ storage condition, the antimicrobial substances did not reduced L. monocytogenes ATCC 19113, meanwhile at $5^{\circ}C$ storage condition, L. monocytogenes ATCC 19113 was reduced in viable number.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.84-97
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• 2016

Isolates from Korean fermented soybean paste were identified as Enterococcus faecium SBP12, Pediococcus halophilus SBP20, Lactobacillus fermentum SBP33, Leuconostoc mesenteroides SBP37, Pediococcus pentosaceus SBP41, Lactobacillus brevis SBP49, Lactobacillus acidophilus SBP55, and Enterococcus faecalis SBP58 according to conventional morphological and biochemical characteristics, carbohydrate fermentation profiling, and 16S rRNA sequence comparison. Strain SBP20, SBP33, SBP49, and SBP55 showed very resistance to simulated gastric and intestinal juices with final populations exceeding 6 log CFU/ml, whereas cells of SBP12 and SBP58 after exposure to low pH were dramatically decreased within 2 h. Among 4 strains having good tolerance to gastrointestinal conditions, the high adhesive ability to HT-29 cells, antibiotic resistance, and antimicrobial activity against food-borne pathogens Bacillus cereus ATCC 11778 and Staphylococcus aureus ATCC 6538 were observed with SBP49 and SBP55, therefore, these two strains were confirmed as putative probiotic candidates. There was no significant difference between the sourdoughs fermented with SBP49 and SBP55 with respect to the values of pH, total titratable acidity, and viable cell count. During sourdough fermentation, SBP49 strain produced significantly greater amounts of lactic acid than SBP55 strain, which secreted large quantities of hydrogen peroxide. SBP49 and SBP55 strains producing the antimicrobial substances such as lactic acid, hydrogen peroxide, and bacteriocin effectively inhibited B. cereus and S. aureus inoculated in the sourdough.

• Journal of Life Science
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• v.7 no.4
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• pp.316-321
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• 1997

The effects of the silver ion-exchanged water treatment agent (Ag-Os) upon E. coli RB 797 and Bacillus sp. have been discussed in this study. Silver ion causes a number of toxic effects with no known biological function. Silver ion-exchanged water treatment agent (Ag-Os) using oyster shell here showed antimicrobial activities. the soluble form of silver ion in water is more toxic to the growth of Bacillus sp. than that of E. Coli RB 797. The minium amount of Ag-Os needed for growth inhibition is 0.2 mg/ml for E. Coli RB 797 and 0.02 mg/ml for Bacillus sp., which is consistant with the data of the survival cell fraction. Binding studies suggested that binding of silver to the cell surface was a rapid, metabolic-independent process and different from active transport. Bacillus sp. showed more binding than E. Coli RB 797. Reducing substances of the cell cultures in the presence of Ag-Os was detected using Methylen blue as an indicator. From these results, we suggest that Ag-Os is effective as an antimicrobial agent on E. Coli RB 797 and Bacillus sp. and silver binds to the cells through rapid, metabolic-independent process and might complex to sulfur group in the cells for its toxicity.