• Geotechnical Engineering
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• v.14 no.4
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• pp.151-162
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• 1998

The compressibility and the permeability of organic soil are so high that they cause many engineering problems when constructing a structure on the soil. If the organic content of the soil could be reduced by any applicable engineering technique, the engineering properties of the soils can be improved to some extent. The purpose of this study would thus be focused on how to decrease the amount of organic matters by applying aerobic biodegradation for eliminating post-construction settlement problems. To enhance the aerobic decomposition, oxygen was supplied to the soil samples prepared by the mixture of kaolinite and sawdust as organic matter. The dissolved oxygen and the organic content of the soil samples were measured, in accordance with the passage of time through the bests. As oxygen suppliers, HaOa liquid and pure oxygen gas were compared to meet the requirement of the test purposes. Newly manufactured oedometer with the diameter of 130 mm and the height of 300 mm was used for 100 days to perform the compressibility tests for the soils. Based on the results of this experiment, the oxygen gas-treated samples with nutrient settled 30% more than the samples untreated. This confirmed the efficiency of the aerobic biodegradation. $NaNO_3$ added into the soils as nutrients was proved more effective than $K_2HP0_4$. To confirm the activity of micro-organisms, sodium azide was also added to the soils.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.70-76
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• 1992

A field experiment was conducted to find out the influence of cropping systems under rotation of paddy-upland soil on soil microorganisms with specific reference to cations concentration in the soil. The results obtained was summarized as follows. 1. The number of soil bacteria and actinomycetes increased in fallow, continuous cultivation of rice and soybean while the number of fungi decreased. 2. Gram negative bacteria as Pseudomonas spp. and Rhizobium spp. remarkably incerased with increasing Gram positive bacteria of Bacillus subtilis in continuous cultivatio of soybean. 3. The relative population of soil born plant pathogen such as Fusarium spp. Rhizoctionia spp. and Phoma spp. to the total soil fungi was high in cultivation of potato and Chinese cabbage. The ratio of soil plant pathogen to the total soil fungi was high in cultivation of potato with Chinese cabbage. 4. The number of bacteria and actinomycetes was positively correlated with ratio of Ca＋Mg/K in soil while negatively correlated with soil fungi.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.198-205
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• 2011

This study was conducted to investigate the effect of feed types on Ochratoxin A (OTA) degradation by Korean native goats. Rumen fluid from canulated goats fed whole roughage or 50% roughage served as a source of micro-organisms. Experiments were undertaken i) to investigate OTA degradation ability in a $2{\times}4$ factorial arrangement with different feed types (100% roughage vs. 50% roughage) and rumen fluid fractions (whole rumen fluid, cells, autoclaved rumen fluid and supernatant) supplemented with OTA ii) to evaluate OTA degradation by the rumen fluid of goats fed two different diets at different time points (0, 3, 6, 9 and 12 h) of feeding iii) to isolate potential rumen microorganisms and iv) to identify elements responsible for OTA degradation. Rumen fluid from goats fed 100% roughage had higher (p<0.05) OTA degradability than 50% roughage diets. OTA degradation based on rumen fluid collection times showed that rumen fluid at 0 h showed significantly higher (p<0.05) degradability. Carboxypeptidase A (CPA) enzyme has been reported to be responsible for OTA degradation. Thus, using real time PCR, primers designed to target the CPA gene from Bacillus licheniformis could be amplified using genomic DNA from rumen fluid of goats and sequenced, thus enabling evaluation of the Bacillus population under different feeding condition and times. Our findings showed that the Bacillus population was significantly higher (p<0.05) before feeding (0 h) in animals which were fed a whole roughage diet, giving indirect evidence of OTA degradation being influenced by Bacillus sps. Thus, it can be concluded that OTA degradability is influenced by feed, feeding time and Bacillus licheniformis population.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.559-565
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• 2002

The physiological functionalities such as antimicrobial activity, antioxidative activity, angiotensin-I converting enzyme (ACE) inhibitory activity and bile acid binding capacity were measured for the solvent-fractionated methanol extracts of Alaska pollack sik-hae at various time intervals during fermentation. Two temperature schemes of fermentation were studied: constant temperature of 2$0^{\circ}C$ (A) and stepwise change from 2$0^{\circ}C$ (10 days) to 5$^{\circ}C$ (B). The methanol extracts of Alaska pollack sik-hae showed antimicrobial activities against 9 kinds of micro-organisms including pathogenic and food poisoning strains. Among these, gram positive bacteria, in particular Staphylococcus aureus, showed more sensitivity to the extracts than gram negative bacteria and fungi. Antioxidative activity (EDA$_{50}$) increased until 15 days (A, 0.92 mg/$m\ell$) or 16 days of fermentation (B, 0.94 mg/$m\ell$), and then gradually decreased. ACE inhibitory activity was observed in all fermentation time except 0 day, and bile acid binding capacity at 15 days (A) and 16 days (B) only.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.166-172
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• 2007

ERM proteins transfer the methyl group to $A_{2058}$ in 23S rRNA, which reduces the affinity of MLS (macrolide-lincosamide-streptogramin B) antibiotics to 23S rRNA, thereby confer the antibiotic resistance on micro-organisms ranging from antibiotic producers to pathogens and are classified into monomethyltransferase and dimethyltransferase. To investigate the differences between mono- and dimethyltransferase, tirD, a representative monomethylase gene was cloned in Escherichia coli from Streptomyces fradiae which contains ermSF, dimethylase gene as well to overexpress the TlrD for the first time. T7 promoter driven expression system successfully overexpress tlrD as a insoluble aggregate at $37^{\circ}C$ accumulating to around 55% of the total cell protein but unlike ErmSF, culturing at temperature as low as $18^{\circ}C$ did not make insoluble aggregate of protein into soluble protein. Coexpression of Thioredoxin and GroESL, chaperone was not helpful in turning into soluble protein either as in case of ErmSF. These results might suggest that differences between mono- and dimethylase could be investigated on the basis of the characteristics of protein structure. However, a very small amount of soluble protein which could not be detected by SDS-PAGE conferred antibiotic resistance on E. coli as in ErmSF which was expected from the activity exerted by monmethylase in a cell.

• Journal of Conservation Science
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• v.29 no.4
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• pp.333-343
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• 2013

The exhibition hall of museum has been damaged by abundant dust and mold of the air in the room. Occurrence of microorganisms on the surface of the cultural heritage will cause damages such as coloration, materials degradation, deterioration, etc. In this study, we investigated the temperature/humidity and microbes distribution in exhibition hall, display showcase, and on surface of wall paintings in the Muwisa museum. From some samples collected in exhibition hall and display showcase, we identified so many varieties of micro-organisms such as Aspergillus sp., Penicillium sp., Cladosporium sp.. In particular, we could see a large number of microorganisms in the number 1, 2 exhibition hall compared with the number 3 exhibition hall. The results examining the distribution of the temperature and humidity were showed as $28{\pm}4^{\circ}C$ and 70~80%, respectively. The number 1 exhibition showcase was higher humidity environment than the number 2, 3 exhibition hall compared to the distribution ratio, which considered as correlation with the distribution of microorganism concentration. As these results, we understood that high temperature and humidity in the exhibition hall and display showcase of the Muwisa museum were characteristics caused by environmental management and hermetically-sealed rooms.

• Korean Journal of Environmental Biology
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• v.38 no.3
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• pp.355-370
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• 2020

We conducted a field survey to analyze the ecological structure and spatial distribution of microplankton (phytoplankton and ciliates) in relation to water masses at 21 stations on the surface and chlorophyll-a maximum layers (CML) in the Northern East China Sea (nECS; 32°-33°N; 124°00'-127°30'E) from August 3 to August 6, 2019. The results showed that the water masses were divided into Chinese Coastal Waters (CCW) and the Tsushima Warm Current (TWC). The CCW showed the environmental characteristics of high temperature and low salinity, and the TWC showed high temperature and high salinity. The characteristics of the phytoplankton community in the CCW showed various community structures related to the nutrients supplied from the large rivers of the Chinese continent. However, the TWC had simple community structures because it originated near the equator and moved northward. The standing crops of phytoplankton and ciliates were very high in the CCW but showed low at the TWC. In particular, from the higher standing crops of protozoa than plant plankton at the TWC, the energy flow at the lower tropic levels caused by the microbial loop that fed on heterotrophic bacteria played an important role in the production of resource organisms. In other words, the marine ecological structure of the nECS in summer could be estimated as a bottom-up system at the CCW and a top-down system at the TWC.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.347-354
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• 2002

Near the Gapcheon, a new suburban city will be developed by the Ministry of Construction and Transportation, and a intracity highway will be constructed by Daejeon Metropolitan City. By these new plans, rapid disruption of environmental conditions near the Gapcheon will be anticipated. The new construction of the city and highway will raise a problem of environmental pollution and disruption of natural status of this area, and will have an adverse influence to environment of the Dunsan area and an industrial complex which are located at the downstream of the Gapcheon. This re-search was conducted on the Gapcheon area, Daejeon (Gasuwongyo to Wonchongyo) from August, 2001 to June, 2002 years. Microorganisms of Gapcheon are three forms, 17 varieties, 105 species, 58 geneva, 31 families, and totalled 125 taxa. And zooidal micro-organisms, one varieties, 16 species, 12 genera, eight families, and totalled 17 taxa. Hydrogen ion concentration of the stream is ranged from 7.10 to 9.98 with great variation, especially high below bridges of Gasuwongyo and Mannyeongyo. The clean water quality of the stream is still maintained very well due to dense distribution of diverse aqua-tic and swamp plants. Furthermore, species diversity of microorganisms in the stream does help to purify the quality of water, and to keep the health of the Gapcheon as natural. More environmentally controlled and continuous efforts to keep the Gapcheon in a natural status and to purify the quality of water should be made by Daejeon Metropolitan City Officials who ave now spending about 6G,5()0 million won for overall conservation plans of the stream (from 1999 to 2003 years).

• Journal of Life Science
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• v.30 no.7
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• pp.581-591
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• 2020

This study investigated the probiotic properties and physiological activities of Korean fermented foods such as sikhae, young radish kimchi, and bean-curd dregs. Among the isolated lactic acid bacteria, Pediococcus inopinatus BZ4, Lactobacillus plantarum SH1, Lactobacillus brevis SH14, Pediococcus pentosaceus YMT1, and Leuconostoc mesenteroides YMT6 demonstrated a greater than 60% survival rate at pH 2.5, along with an excellent survival rate even at 0.3% bile acid. These five bacteria showed strong flocculation ability in autoaggregation and coaggregation tests, indirectly clustering useful micro-organisms and inhibiting the attachment of pathogenic bacteria. In a cell surface hydrophobicity test, these bacteria showed adhesion to three solvents (ethyl acetate, chloroform, and xylene) and high hydrophobicity, thereby indicating excellent indirect cell adhesion to intestinal cells. The cell-free supernatants and intracellular extracts of the five lactic acid bacteria showed antioxidative activity in the form of 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging ability and lipid peroxidation inhibition. Antimicrobial activities were also observed in four pathogenic bacteria, namely E. coli KCTC 2571, H. pylori HPKCTC B0150, L. monocytogenes KCTC 13064, and S. aureus KCTC 1916. These results demonstrate that these five lactic acid bacteria could be used as probiotics with antioxidant and antimicrobial properties.

• Journal of Internet of Things and Convergence
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• v.6 no.2
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• pp.19-24
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• 2020

In the present study, using biological information of bacteria and biochemical information of chlorine dioxide gas, Gram-positive bacteria, e.g., Alloiococcus otitis, Erysipelothrix rhusiopathiae, Staphylococcus caprae, Staphylococcus lentus, and gram-negative bacteria, e.g., Acinetobacter baumannii complex, Aeromonas salmonicida, Brucella melitensis, Oligella ureolytica were used whether a plastic kit to release ClO₂ gas could inhibit their growth. Overall, chlorine dioxide gas showed about 99% inhibition of bacterial growth, with less than 10 CFU. However, it was found that Gram positive Alloiococcus otitis and Gram negative Aeromonas salmonicida had more than about 50 CFU. When comparing the results of experiments with several bacteria, it suggested that the concentration of chlorine dioxide gas would be at least 10 ppm to 400 ppm for the bacterial inhibition. The results of this study could be used as basic data to evaluate the clinical usefulness of chlorine dioxide gas. If this study helps with prior knowledge to help clinicians to recognize and prevent the presence of micro-organisms that cause infections in hospitals, it would be helpful for activities such as patient care as a convergence field. In the future, it is considered that the research results will be the basis for rapidly inhibiting the microbes infected with patients by utilizing data of the information of the microbes that are inhibited for chlorine dioxide gas.