• Journal of fish pathology
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• v.23 no.1
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• pp.37-45
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• 2010

In this study, we carried out research on the level of single and multi-drug resistance of bacteria isolated from cultured flounder Paralichthys olivaceus. One hundred sixty one bacteria were isolated from cultured olive flounder Paralichthys olivaceus in Korea and the isolates consisted of Edwardsiella tarda (n=32), Vibrio ichthyoenteri (n=37), Vibrio spp. (n=54), Streptococcus parauberis (n=28) and Streptococcus spp. (n=10). These E. tarda isolates were highly resistant in the order of tetracycline (84.4%) and oxolinic acid (71.9%). V. ichthyoenteri and Vibrio spp. showed resistance ampicillin (94.6% and 81.5%) and tetracycline (56.8% and 42.6%). S. parauberis isolates were resistant ampicillin (57.1%), tetracycline (57.1%) and erythromycin (35.7%). Of the isolates, 84.4% of E. tarda, 73.0% of V. ichthyoenteri, 57.4% of Vibrio spp., 42.8% of S. parauberis and 70.0% of Streptococcus spp. isolates exhibited multi-drug resistance against more than two antibiotics.

• Research in Plant Disease
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• v.18 no.3
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• pp.217-224
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• 2012

Post-harvest rot of grape causes a severe economic loss and lower of the grape quality. It is also one of the important limiting factors for grape export. Grape rots and their casual agents on 'Red Globe' variety imported from Chile were identified. Grapes shown rotting symptom were collected from the storages near the import harbor. The 3 different rots were identified on the imported 'Red Globe'; melting decay, gray mold, and blue mold. A bacterium that isolated from a typical melting decay symptom was identified as Gluconobacter cerinus on basis of its nucleotide sequence of 16S rDNA and fatty acid profile. By inoculation on grape, it caused cracking and dissolution of epidermis of grape which were the characteristics of melting decay. Botrytis cinerea and Penicillium expansum were isolated from grapes showing gray mold and blue mold. The 2 fungal isolates were identified on basis of their morphological characteristics and nucleotide sequence of their beta-tubulin genes. They showed strong pathogenicity on 'Campbell Early' variety that is a major table grape in Korea.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.212-218
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• 1999

The effects of gamma irradiation (1, 3 and 5 kGy) and packaging methods (air and vacuum) on the growth of microorganisms contaminated in beef was investigated during storage at different temperatures (-20, 4 and $25^{\circ}C$). The initial microbial population of beef was $8.0{\sim}10^2\;CFU/g$ in total aerobic bacteria, $2.0{\times}10^2\;CFU/g$ in total lactic acid bacteria, $8.0{\times}10^1\;CFU/g$ in molds, $6.0{\times}10^2\;CFU/g$ in Pseudomonas sp. and $7.0{\times}10^2\;CFU/g$ in coliforms, respectively. Gamma irradiation at 5 kGy completely eliminated pathogenic bacteria in beef. Gamma irradiation at such dose and subsequent storage at less than $4^{\circ}C$ could ensure hygienic quality prolong the microbiological shelf-life resulting from the reduction of spoilage microorganisms. The different packaging methods of beef caused negligible changes in the growth of microorganisms during storage.

• Journal of fish pathology
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• v.5 no.1
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• pp.37-48
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• 1992

Antibiotics are chemical substances produced by various species of microorganisms that suppress the growth of other microorganisms or may destroy them. Among the more than 4000 antibiotics that has been identified, about 20s are using as the therapy of infectious fish diseases. There are several methods used to classify and group antibiotics, and the most common classification has been based on chemical structure and proposed mechanism of action. The effect of antibiotics may be determined by the kind of fish pathogens and by the external environment surrounded the infected fish. It implies that the kind of antibiotics and its application method should be decided after the determination of the reasons of fish disease. The uncontrolled usages of antibiotics may induce the selection of resistant mutants appeared spontaneously and present in any group of bacteria. The epidemic spread of such antibiotic resistant strains of fish pathogenic bacteria already has been reported in various districts of japan. Importantly, transferable drug resistant(R) plasmids were detected in strains of most of fish pathogens. Based on those reports, the antimicrobial resistance appears to be a rapidly emerging problem in the fish industry on the country. The expanding literatures on the pharmacokinetics, clinical trials, withdrawal periods and efficacy of environmental effect for the commonly using antibiotics have met the needs of data for the practical application of antibiotics. However, the most important thing for the treatment of fish diseases would be the communication and exchanging of information between the site of aquaculture and the diagnostic laboratory.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.121-126
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• 2018

The oral hygiene of patients admitted to the ICU (Intensive Care Unit) is very important. Critically ill patients are basically immunocompromised ones because of the high risk of infection by various pathogenic bacteria. The mouth is not only the primary site of infection, but also the site of systemic infections. The purpose of this study was to design a mouthpiece type vacuum oral cleaner for the oral care of seriously ill patients. A 3D CAD modeling and flow analysis model were established for a double structure type cleaner and standard tooth model, and their pressure and flow characteristics were analyzed. The pressure inside the oral cleaner was almost constant, but the velocity distribution showed a large difference between the inside and outside of the teeth. The velocity at the center region inside of the teeth was the highest, and the speed decreased as the distance from the center increased. In the analysis of the case where the suction tube was replaced by the drainage tube, the velocity at the center of the outer portion of the teeth was the highest. In order to increase the effectiveness of the oral cleaner, alternating between suction and drainage is proposed, and a design complement to increase the speed of the molar region is required.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.271-277
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• 2010

The purpose of this study is to investigate the seasonal variation of picoplankton community in Lake Juam depending on the change of physico-chemical factors such as rainfall, water depth, DO and pH. The concentration of chlorophyll-a was most high as 18.03 mg/$m^3$ in July when the rainfall and water temperature were highest. The concentration was gradually decreased in October, April and that of January was decreased most low as 1.86 mg/$m^3$. The highest concentration of the Chl-a was shown at 2 and 5 m of water depth than surface, and the concentration was gradually decreased when the water depth becomes deep. Overall, microplankton was the highest rate as 33.9~54.2%, nanoplankton was 24.3~30.5% and picoplankton was 21.6~41.2%. Picoplankton was included as considerable concentration in the water of Juam lake. Therefore it is necessary to remove thoroughly the picoplankton in the water treatment processes such coagulation·sedimentation and sand filtration. The protoplasm released from destruction of picoplankton by chlorine has high possibility to cause regrowth of bacteria and pathogenic microorganism in the distribution system by playing the role of the assimilable organic carbon.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.667-673
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• 2017

This study was carried out to verify the antimicrobial effect of Graviola leaves against pathogenic bacteria for the purpose of developing an antibacterial material. The extraction conditions of graviola leaves were $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$, and graviloa leaves werewater extracted at $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$.The extraction yields and extraction conditions were determined. The antimicrobial activity against S. epidermidis, S. aureus and E. coli TOP10 was evaluated by agar diffusion method. The extraction yields were 3.02%, 14.73% and 20.76% at $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$, respectively. The antimicrobial activity against S. epidermidis, S. aureus and E. coli TOP10 was found in S. epidermidis.In the samples extracted at $98^{\circ}C$, a clear zone of 13 mm was observed at 200 mg/mL and of 20 mm at 500 mg/mL. The MIC was 100 mg/mL. The higher the extraction temperature and concentration, the better was the growth inhibition effect. As a result, the natural antimicrobial activity contained in natural materials can solve the problem of resistance to antibiotics. It is considered that antimicrobial activity against S. epidermidis in skin is highly applicable to basic cosmetics and cosmetic materials.

• Korean Journal of Veterinary Service
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• v.32 no.4
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• pp.353-359
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• 2009

Interest in marine organisms as potential sources of bioactive agents has increased in recent years. The red seaweed, Callophyllis (C.) japonica, is abundant in the coastal regions of Jeju Island in South Korea. A previous study shows that C. japonica extracts have antioxidant activity and radioprotective effects. In this study, an methanol extract of C. japonica was tested whether it has antibacterial effects against the bacteria from swine. In vitro antibacterial activities of the crude extracts prepared from the C. japonica using 80 % methanol were tested for inhibitory activity against the Escherichia (E.) coli (S175), Enterococcus (E.) faecium (ATCC 51558), Salmonella (S.) Typhimurium and Staphylo-coccus (S.) aureus (ATCC 25923) by using broth dilution method. All organisms were incubated in brain heart infusion medium containing 1% extract at 0, 4, 8, 12 and 24 hrs. The 3 days-old piglets were fed an experimental diet supplemented with 1% C. japonica for 1 week. And the change of the coliform bacteria in feces were examined after supplement of C. japonica for 1 week. When the inocula containing $10^2{\sim}10^3$CFU/ml of each organism were used the extracts of C. japonica showed various degrees of antibacterial effects on all bacteria tested. The CFU value ($6.3\times10^8$CFU/ml) of C. japonica for E. coli was decreased 30% compared with vehicle controls ($9.0\times10^8$CFU/ml) after 8 hrs incubation. The proliferation rate of E. faecium was inhibited about 68% at 4 hrs, 81% at 8 hrs and 76% at 12 hrs after incubation, respectively. The proliferation rate of S. Typhimurium was inhibited about 96% at 4 hrs, 90% at 8 hrs and 72% at 12 hrs after incubation with extracts of C. japonica. The proliferation rate of S. aureus was inhibited more than 90% each time courses. Conclusively, a red seaweed extract of C. japonica was found to be effective against a number of gram negative and gram positive bacteria such as E. coli, E. faecium, S. Typhimurium, and S. aureus. The number of coliform bacteria was increased in the 1% C. japonica-treated group, as compared to those of controls. This result suggests that C. japonica extracts be added as an effective natural antibacterial agent. The precise mechanism of antibacterial effects and its application on swine industry remains to be further studied.

• Journal of fish pathology
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• v.25 no.1
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• pp.21-30
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• 2012

Effects of various concentration of skullcap Scutellaria baicalensis in the diets on a nonspecific immunity and a disease resistance of olive flounder were investigated. After feeding trial, weight gain of fish fed 0.05% skullcap immersed group was higher than that of fish fed 0, 0.1 and 1% skullcap diet but no significant differences were observed among the experimental groups. Furthermore, no significant differences in hematological indices of olive flounder were found among the experimental groups. Lysozyme activity in the serum and kidney of the administrated group(0.05% skullcap immersed group) was significantly higher than the control group. In addition, the chemiluminescent(CL) responses of head kidney leucocytes from the 0.05% skullcap immersed group was significantly higher(P<0.05) than the control group. In the histological results, the 1% skullcap immersed group appeared to have the detrimental effects for fish health. In a challenge experiment with Edwardsiella tarda(GY-01) and Streptococcus iniae(FT5228), relative percent survival (RPS) in the 0.05% skullcap immersed group was higher than the control group injected with E. tarda(GY-01) at $4^{th}$ and $8^{th}$ weeks. The results suggest that the skullcap extract (0.05%) would be effective to enhance the nonspecific immunity and protective ability of olive flounder against fish pathogen such as E. tarda.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.357-362
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• 2006

Bacillus thuringiensis strains were isolated from the domestic soil and a strain was selected that had a new host range and high toxicity against agriculture insect pest. The 142 samples of soil were sampled from the mountains, paddy fields and patches, in Daejon, Chungnam, Chungbuk and Jeonbuk and used for the investigation. Sixteen B. t strains were isolated from 12 samples among collected samples. There were 11 strains that showed toxical activity on Plutella xylostella (Lepidoptera: Yponomeutidae), 7 steins on Spodoptera litura (Lepidoptera: Noctuidae), 5 strains on Arete coerulea (Lepidoptera: Noctuidae), 5 strains on Culex pipiens pallens (Diptera: Culicidae) among the 16 isolated B. t strains. But there were not any strains that showed activity against Hyphanria cunea (Lepidoptera: Arctiidae) and Sitophilus oryzae (Coleoptera: Rhynchophoridae). And also some of B. thuringiensis strains showed insecticidal activity with 2, 3 or 4 kinds of insects. But there were also 3 strains that did not show any activities to the 6 insects which were used in the experiment. When examined with a phase-contrast microscope, the insecticidal crystal protein produced from 16 selected strains had 13 bipyramidal and 3 spherical shapes. The insecticidal bioactivity of the S. litura showed 100% mortality when there were $1.3{\times}10^{7}\;(cfu/ml)$ of CAB109 isolates.