• Korean Journal of Microbiology
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• v.50 no.4
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• pp.384-386
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• 2014

Pseudomonas aeruginosa is an opportunistic pathogen that inhabits various natural and artificial environments, such as pathogenesis, water, soil and air. They can cause serious problems, such as pathogenic infection. In this study, 220 colonies were isolated from water and soil environment that assumed to be P. aeruginosa using a membrane filter method based on International Organization for Standardization (ISO/NP 16266). Identification of the isolates was determined by physiobiochemical characteristics using newly modified ISO method which includes the resistance to 1,10 phenanthroline test. Only one of 220 presumed P. aeruginosa strains isolated from effluence water using a drain swab was determined as P. aeruginosa-positive by the ISO/NP 16266 method. Subsequently, the resistance to 1,10 phenanthroline test, which was newly proposed by ISO in 2014 and applied in this study, was considered as more precise and improvable method for identification of P. aeruginosa.

• Korean Journal of Oriental Medicine
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• v.12 no.1
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• pp.49-57
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• 2006

Objectives : This study has attempted to establish an organized system for the microbiological quality of raw materials which are important factors in preparing the standard for microbial limits. Methods : This study has first set up microbial contamination limit test. total aerobic microbial count and total fungi count, int accordance with testing method of the Korea Pharmacopeia 8th edition in order to establish an inspection standard for microbial contamination. Results : The microbial contamination of 18 items that are highly prone to contamination by three regions(Seoul, Daejeon, Gyeongsangbuk-do), As a result, Morus alba Linne and Rehmannia glutimosa Liboschitz var. purpurea Makino showed as high contaminated by WHO's Microbial Contamination Limit standard. In case of Yukjin medicine in the Theory of Herb Medicinal Properties, total bacterial contamination rate showed as 17.7%, total fungal contamination rate showed as 41.2% and total aerobic mircobial count and total fungi count on Ephedra sinica Stapf. Pinellia ternate Breitenbach, Evodia officinalis Dode showed as high measured. The microbial conatmination rate materials which make up Yukmijihwanghwan were mostly high therefore the total aerobic microbial count was measured as high in case of Yukmijihwanghwan, the characteristics about microbial contamination strain is to be researched. Conclusions : By combining the basic data and experimental results related to microbial contamination of herb medicine, the most ideal storage standards for herb medicine has been attempted to be presented.

• Korean Journal of Microbiology
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• v.32 no.2
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• pp.102-108
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• 1994

Autonomously replicating sequence Binding Factor 1(ABF1) is a DNA-binding protein that specifically recognizes the $RTCRYN_5ACG$ at many sites in the yeast genome including the promoter element, mating-type silencer and ARS. To express the intact full-length ABF1 gene in E. coli, the ABF1 gene has been cloned into pMAL-c2 and His-61, Leu-353 and Leu-360 were substituted with other amino acid. ABF1 fusion proteins of wild type ABF1 and H61A, L353R and L360R nutants were purified by amylose resin affinity chromatography. Fusion protein of MBP and ABF1 was digested by Factor Xa and Characterized by gel retardation assay and complementation test. As aresult, we suggested that other DNA binding motif except atypical inc-finger motif is in the middle region of ABF1.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.272-279
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• 2018

This study was carried out to evaluate antimicrobial activity of isolated bacteria from various soils against two strains of Propionibacterium acnes causing acne vulgaris. Among several hundreds of bacterial strains, Paenibacillus elgii DS381, Paenibacillus elgii DS1515, Burkholderia gladioli DS518, and Streptomyces lienomycini DS620 showed high antimicrobial activities against the strains of P. acnes. All isolated bacteria showed 15.5 to 34.3 mm inhibition zone diameter in an agar well diffusion test, and especially DS620 showed the highest inhibition zone diameters (28.3~34.3 mm). Antibacterial substances were expected as lipopeptide (pelgipeptin and paenipeptin) from strains DS381 and DS1515, protease from DS518, and anthracycline antibiotic (daunomycinone) from DS620, and all these showed very low minimum inhibitory concentration [DS381 and DS1515 (0.078 mg/ml), DS518 (0.312 mg/ml), DS620 (0.000078 mg/ml)] against P. acnes. These antibacterial substances could completely kill P. acnes within 24 h in a time-kill assay. These results suggest that antibacterial substances produced by these bacteria may be utilized as useful antimicrobial agent against P. acnes and treatment medicine for acne vulgaris.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1066-1075
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• 2017

This study was carried out to determine the functional works and basic ingredients of Sagoonja-Tang on sponge cake. The experimental groups consisted of 6% mixtures of five (Ed-confirm the number) kinds powders : S1 for Sagoonja-Tang powder, S2 for Panax ginseng, S3 for Poria cocos, Koidz, S4 for Atractylodes macrocephala, and S5 for Glycyrrhiza uralensis Fisch. The volume of sponge cake somewhat decreased after adding the ingredients, and the volume differences in order from highest to lowest, were control>S1>S3>S2>S4>S5. In the microbiological quality test, viable cell counts were high in control groups of sponge cake, and the numbers of viable cell for control sponge cake reached to $9{\times}10^7CFU/g$ on the 7th day of storage, and decreased to $2.5{\times}10^5CFU/g$ on the 10th day of storage. All sponge cakes added with ingredient's powder showed pretty low viable cell counts. Especially, the group S5 showed the lowest counts of $1.2{\times}10^2CFU/g$ on the 7th day of storing. In the texture analyses of sponge cake, All groups showed higher degree of hardness, gumminess and chewiness than SC. The antioxidative activity of the Sagoonja-Tang's ingredients was measured. The POV value measured was S5>S4>S3>S2 >S1>control in order of highest to lowest. In sensory test, the overall acceptability of sponge cake was from highest to lowest S3>SC S2>S1>S5>S4.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.265-272
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• 2017

Some bacteria with different mechanisms for hydrocarbon degradation were isolated from oil-contaminated soils in Korea. Isolate Acinetobacter calcoaceticus SL1 showed biosurfactant- producing activity in oil-spreading test, and it exhibited a good emulsifying activity of 43.6 and 54.5% for diesel oil and n-hexane, respectively. It also has high cell surface hydrophobicity which can make it easily attaches to hydrocarbons and degrade them. It degraded 100% of 1,000 mg/L of n-octadecane and naphthalene, respectively in 3 days, 72.3% of 1,000 mg/L diesel oil in 7 days and 78.0% of 10,000 mg/L diesel oil in oil-contaminated soil during 28 days. Isolated strains Bacillus amyloliquefaciens S10 and B. subtilis GO9 can produce biosurfactant and formed 6.34 and 2.5 cm diameter of clear zones, respectively in oil-spreading test. Surface tension of their culture supernatant reduced from 74.6 to 34.4 and 33.3 mN/m, respectively during incubation, and critical micelle concentrations of culture supernatants were 2.0 and 5.9%, respectively. Consortium of A. calcoaceticus SL1 and B. amyloliquefaciens S10 degraded 77.8% of 10,000 mg/L diesel oil in 3 days, which indicated more efficient oil degradation than that by A. calcoaceticus SL1 alone. If these bacteria were applied together as a consortium to oil-contaminated sites, they may show a high removal rate of petroleum hydrocarbons.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.48-56
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• 2024

Objectives: The coronavirus pandemic that began in 2019(COVID-19) has been one of the worst pandemics of the 21st century. Masks have been used to prevent COVID-19, but there are currently no standards for the long-term use of masks in the Republic of Korea. This study was conducted to assess the microbiological safety of KF94(Korea Filter 94) disposable face masks according to wearing duration by evaluating the bacterial filtration efficiencies of masks worn by research participants. Methods: A commercially available KF94 mask certified by the Ministry of Food and Drug Safety(MFDS) in the Republic of Korea was selected as the test mask. The research participants(n = 15) wore masks for the durations of one, three, and seven days. Participants also reported several parameters, including wearing time, makeup frequency, and storage. Bacterial filtration efficiencies of the worn masks were measured by a mask bioaerosol filtration tester. Staphylococcus aureus(S. aureus) was used as the test bacteria and quantitatively measured through the cultivation method. Then, bacterial filtration efficiency was calculated using the formula suggested by the MFDS. Results: All worn masks showed over 99.98% of mean bacterial filtration efficiency for S. aureus. There were no significant differences among bacterial filtration efficiencies of face masks according to wearing duration. There was also no significant difference among bacterial filtration efficiencies among participants. There was no correlation between the results of bacterial filtration efficiencies and reported parameters from participants. Conclusions: In the absence of significant external damage to the mask, the bacterial filtration efficiency of the mask can be maintained even after seven days of wearing. This result suggests that KF94 masks certified by the MFDS can be used repeatedly for about a week without loss of bacterial filtration efficiency.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.7-13
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• 2015

Hydrotrope-combined copper (HCC) is a copper ($Cu^{2+}$)-based algicide, which is combined with a hydrotrope that keeps copper ion in solution to improve performance. This study assessed the growth inhibition effect of HCC against Microcystis aeruginosa which is one of the most common toxic cyanobacterium in eutrophic freshwater environment. Various HCC doses, ranging from 5.5 to $550{\mu}g/L$ as $Cu^{2+}$, were applied to either BG-11 or 1/4 diluted medium with low- or high-inoculum density of M. aeruginosa. Growth inhibition was monitored based on a decrease in chlorophyll-a content in culture medium during the incubation. Results showed that HCC significantly inhibited the growth of M. aeruginosa in a dose-dependent manner. In case of 1/4 diluted BG-11 medium, HCC dose as low as $5.5{\mu}g$ $Cu^{2+}/L$ completely inhibited the production of chlorophyll-a by M. aeruginosa. It was found that HCC did not induce any significant release of microcystin-LR from M. aeruginosa. Acute toxicity of HCC was tested using Daphnia magna, and the 24-h $EC_{50}$ value was 0.30 mg/L as $Cu^{2+}$ which was much higher than the actual inhibition dose. Ames test was performed using Salmonella enterica serovar Typhimurium TA100, and HCC showed no increase in the number of revertant colonies. The result suggested that HCC does not have any mutagenic potential in the aquatic environment. In addition, no genotoxic effect of HCC was also confirmed based on the SOS ChromoTest using Escherichia coli PQ37. Therefore, HCC could be used as a relatively safe and effective pre- and post-treatment agent to control hazardous algal blooming in aquatic environments.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.172-178
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• 2013

The strains were added to the feed in the concentration of $10^3$, $10^5$, and $10^7$ CFU/kg and 2% of fishes were given the feed twice a day (8 AM and 5 PM) for 12 weeks. In result of the nonspecific immune response study to examine Respiratory burst activity, Lysozyme activity and Phagocytosis activity every two weeks until the end of the study, all test samples showed greater activities than control samples and improved immune activity with Bacillus sp. IS-2. The mortality test performed by artificial infection using Streptococcus iniae, a pathogenic bacterium, after the completion of this study also showed over 55% greater survival rate in all test samples. In result of performing PCR using the universal primer to verify that the probiotic stays in the intestines of the fishes, all test samples showed PCR product of 1,465 bp. Based on the above findings, it was concluded that Bacillus sp. IS-2 in the feed improved farmed flatfish's immune system and resistance against diseases as the probiotics. Also, the physiological indicators discovered by this study would be useful for identifying the mechanisms of probiotics.

• Journal of Food Hygiene and Safety
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• v.29 no.3
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• pp.189-194
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• 2014

This study was conducted to evaluate microorganism contamination of food utensils and service facilities in school and to prevent hazards by food poisoning occurrence. As a result, the highest number of microorganism growth plate ($12.3{\pm}2.6$) was detected in total bacteria test plate, and also observed $10.3{\pm}3.9$ growth plates in Staphylococcus aureus test plate and $9.5{\pm}3.9$ growth plates in E. coli and coliform bacteria test plate. But we could detect to the lowest number of growth plates ($1.5{\pm}1.0$) in Vibrio test plate. We also assessed that floors were appeared to the highest microorganism contamination rate in food utensils and service facilities. Therefore, $4.5{\pm}0.6$ growth plates was detected in pre-operation floor and $4.3{\pm}1.0$ growth plates in floor. And high level of microorganism contamination also observed in tables as $3.3{\pm}1.0$ growth plates in cooking table and $3.0{\pm}0.0$ growth plates in dining table. The level of microorganism contamination of food utensils such as kitchen knife, cutting board, and food tray were lower than that in food service facilities. We analysed microorganism contamination according to purpose of use in kitchen knifes and cutting boards. The microorganism contamination rate in fish kitchen knife ($2.0{\pm}0.8$) and fish cutting board ($1.3{\pm}1.5$) were slightly higher than that of others purpose of use. As a result of microorganism identification, various strains of microorganism were contaminated in food service facilities and some strains could detected more than two times. Especially, Staphylococcus aureus was repeatedly identified in cooking table, trench, and kitchen knife. Bacillus cereus was identified in kitchen knife, and then Pseudomonas fluorescens and Pseudomonas aeruginosa were also detected in food utensils and service facilities as known to food spoilage microorganisms. Klebsiella pneumoniae was detected four times repeat, which widely distribute natural environment as normal bacterial flora but sometimes cause acute pneumonia. These results suggest that food utensils and service facilities are contaminated with not only major food poisoning microorganisms such as Staphylococcus aureus, but also food spoilage microorganisms. Taken together, strict personal hygiene control and efficient food service facilities management will be needed to enhance food safety in school feeding and to improve student health.