• Research in Plant Disease
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• v.28 no.1
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• pp.19-25
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• 2022

Ginseng is an important medicinal plant cultivated in East Asia for thousands of years. It is typically cultivated in the same field for 4 to 6 years and is exposed to a variety of pathogens. Among them, ginseng root rot is the main reason that leads to the most severe losses. In this study, endophytic bacteria were isolated from healthy ginseng, and endophytes with antagonistic effect against ginseng root rot pathogens were screened out. Among the 17 strains, three carried antagonistic effect, and were resistant to radicicol that is a mycotoxin produced by ginseng root rot pathogens. Finally, Bacillus velezensis CH-15 was selected due to excellent antagonistic effect and radicicol resistance. When CH-15 was inoculated on ginseng root, it not only inhibited the mycelial growth of the pathogen, but also inhibited the progression of disease. CH-15 also carried biosynthetic genes for bacillomycin D, iturin A, bacilysin, and surfactin. In addition, CH-15 culture filtrate significantly inhibited the growth and conidial germination of pathogens. This study shows that endophytic bacterium CH-15 had antagonistic effect on ginseng root rot pathogens and inhibited the progression of ginseng root rot. We expected that this strain can be a microbial agent to suppress ginseng root rot.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.356-361
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• 2022

Bacillus sp. is a useful strain for agriculture because it promotes plant growth and controls plant pathogens through a variety of mechanisms. In this study, we obtained a microbial preparation with a high number of viable cells by culturing newly isolated soil bacteria on an optimized medium. Subsequently, we applied this preparation to lettuce to enhance its growth and yield. First, B. amyloliquefaciens ISP-5 was isolated from soil. Next, optimization of culture medium was carried out using 5 L scale fermenters. When culturing B. amyloliquefaciens ISP-5 on this optimized medium, the number of viable cells was approximately 1000 times higher than that obtained from culturing on the commercial medium. Afterwards, the plant growth promotion properties of the ISP-5 strain were evaluated using lettuce as a test plant. Foliar spray treatment of lettuce was carried out by inoculating half the standard concentration suspension (0.5 × 10⁷ cfu/ml). As a result, leaf width increased by 8.6% and leaf length increased by 12.9% compared to the control group. Live weight also increased by 24.2% and dry weight by 23.9%. Considering the results from field test, B. amyloliquefaciens ISP-5 showed potential as a plant growth-promoting bacteria.

• International Journal of Oral Biology
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• v.48 no.2
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• pp.9-18
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• 2023

The rapid detection of bacteria in the oral cavity, its species identification, and bacterial count determination are important to diagnose oral diseases caused by pathogenic bacteria. The existing clinical microbial diagnosis methods are time-consuming as they involve observing patients' samples under a microscope or culturing and confirming bacteria using polymerase chain reaction (PCR) kits, making the process complex. Therefore, it is required to analyze the development status of substances and systems that can rapidly detect and analyze pathogenic microorganisms in the oral cavity. With research advancements, a close relationship between oral and systemic diseases has been identified, making it crucial to identify the changes in the oral cavity bacterial composition. Additionally, an early and accurate diagnosis is essential for better prognosis in periodontal disease. However, most periodontal disease-causing pathogens are anaerobic bacteria, which are difficult to identify using conventional bacterial culture methods. Further, the existing PCR method takes a long time to detect and involves complicated stages. Therefore, to address these challenges, the concept of point-of-care (PoC) has emerged, leading to the study and implementation of various chair-side test methods. This study aims to investigate the different PoC diagnostic methods introduced thus far for identifying pathogenic microorganisms in the oral cavity. These are classified into three categories: 1) microbiological tests, 2) microchemical tests, and 3) genetic tests. The microbiological tests are used to determine the presence or absence of representative causative bacteria of periodontal diseases, such as A. actinomycetemcomitans, P. gingivalis, P. intermedia, and T. denticola. However, the quantitative analysis remains impossible, and detecting pathogens other than the specific ones is challenging. The microchemical tests determine the activity of inflammation or disease by measuring the levels of biomarkers present in the oral cavity. Although this diagnostic method is based on increase in the specific biomarkers proportional to inflammation or disease progression in the oral cavity, its commercialization is limited due to low sensitivity and specificity. The genetic tests are based on the concept that differences in disease vulnerability and treatment response are caused by the patient's DNA predisposition. Specifically, the IL-1 gene is used in such tests. PoC diagnostic methods developed to date serve as supplementary diagnostic methods and tools for patient education, in addition to existing diagnostic methods, although they have limitations in diagnosing oral diseases alone. Research on various PoC test methods that can analyze and manage the oral cavity bacterial composition is expected to become more active, aligning with the shift from treatment-oriented to prevention-oriented approaches in healthcare.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.975-984
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• 2005

This study fulfilled to investigate the feed efficiency, tissue selenium distribution, carcass characteristic and economic value in finishing Hanwoo steers fed organic selenium mix (OSM) which included seleno-yeast, rumen culture and other microbial supplements. Forty five finishing Hanwoo steers were tested for 4 months dividing to three feeding groups: OSM add as 0.5 ppm Se of DM feeds (0.5 ppm OSM), OSM enriched add as 1.0 ppm Se of DM feeds (1.0 ppm OSM) and basal diet without OSM (control). The total weight gains, the average daily gains and the feed intakes were not differ in treatments (p > 0.05). No differences (p > 0.05) were noted for hot carcass weight, loin eye area, backfat thickness, meat yield index, meat color, fat color, tenderness and maturity. However, the 1.0 ppm OSM showed better performances for feed requirement, TDN per gain, meat yield grade and meat quality grade compared to other groups. Tissue selenium distribution was increased by organic selenium feeding: higher Se concentration in liver and rump of 0.5 ppm OSM (p < 0.05), and kidney, liver, sirloin and rump of 1.0 ppm OSM (p < 0.05) than the tissues of control group. Generally, tissue selenium was the highest value in 1.0 ppm OSM and showed higher concentrate in order; kidney, liver, sirloin and rump. The income over feed cost was 1.06-fold higher in 1.0 ppm OSM than control group. In conclusion, organic selenium mix supplementation and its amounts were not influenced to feed intake, body gain and carcass characteristic but significantly increased tissue selenium. Therefore, these results suggest that finishing Hanwoo steer fed an enriched organic selenium mix with proper probiotics is able to produce “high-Se” beef as high bioavailable form as well as create a beneficial opportunity on Hanwoo farm.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.167-173
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• 2005

Background : Airborne particles during Yellow Sand phenomena are known to be associated with the respiratory disease. The purpose of this study was to evaluate the concentration and metal component properties of Yellow Sand particles and compare with airborne microbial concentration and species in non Yellow Sand and Yellow Sand phenomena. Methods : Samplings were carried out in 2002 in Seosan, during non Yellow Sand and Yellow Sand phenomena. Samples were taken using the 8-stage Cascade impactor and metallic elements were analyzed by XRF. Those were culture on the media for bacterial and fungal culture and celline for virus. Results : The concentration of total suspended particulate matter were respectively $80.2{\mu}g/m^3$, $40.3{\mu}g/m^3$ in non Yellow Sand and Yellow Sand phenomena. The concentration of metallic elements such as Ca, Fe, Cu and Zn in Yellow Sand phenomena were higher than its in non Yellow Sand. Two bacteria, Bacillus species and Staphylococcus were grown in two periods. In both periods, several fungal spores(Mucor species, Cladosporum, Alternaria, Aspergillus, Penicillium, and Alternaria species) were identified. The differences of bacteria and fungus species not observed in Yellow Sand and non Yellow Sand. Any viruses were not isolated in between both periods. Conclusions : The concentration of total suspended particulate matter and some metallic elements in Yellow Sand phenomena were higher than its in non Yellow Sand. The difference of bacteria and fungus species was not observed in non Yellow Sand and Yellow Sand phenomena.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.1
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• pp.15-24
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• 2005

Enterobacter intermedium oxidizes glucose to gluconic acid and sequentially converts gluconic acid to 2-ketogluconic acid (2-KGA) under aerobic condition. Shaking incubation of E. intermedium in a broth medium containing 22.5 g glucose, 8.2 g gluconic acid and 40 g rock phosphate per liter resulted in $1028mg\;L^{-1}$ soluble phosphate. The culture broth was used as phosphate bio-fertilizer (PBF) in this experiment. To evaluate PBF produced by E. intermedium on lettuce growth, five treatments (PBF1/3, PBF2/3, PBF3/3, BP, and MF) were used. In MF and BP treatments, $P_2O_5$ 5.9 kg of mineral fertilizer per 10a was added, while in PBF1/3, PBF2/3, and PBF3/3 treatments, culture broth containing one third, two third, and same amount of soluble $P_2O_5$ 5.9 kg per 10a was applied, respectively. At 20, 35, and 50 days after transplanting of lettuce, plant growth components, biomass, enzyme activities and soil chemical properties were analyzed. Dehydrogenase activity and available phosphate concentration of rhizosphere in phosphate bio fertilizer treatments (PBF1/3, PBF2/3, PBF3/3) were generally higher compared to MF and BP treatments. Soil biomass in PBF3/3 treatment was significantly higher than MF and BP treatments at early growth stage. However, there was no significant difference among all treatments with time. Plant fresh weights in PBF1/3, PBF2/3, and MF treatments were better than those in BP and PBF3/3 treatments. However, in PBF2/3 treatment the highest fresh weight was discovered where alkaline phosphatase activity was generally higher than other treatments at 35 and 50 days. Enhancement of lettuce growth at 35 and 50 days in PBF2/3 treatment was associated with greater phosphate uptake in lettuce tissue. As regarding all results, PBF showed better lettuce growth compared to mineral phosphate fertilizer where PBF2/3 treatment resulted in increase of lettuce fresh weight by 23% and phosphate uptake by 50%.

• Tuberculosis and Respiratory Diseases
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• v.66 no.5
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• pp.358-364
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• 2009

Background: The appropriate empirical antimicrobial choice in the treatment of community-acquired pneumonia (CAP) should be advocated by community-based information on the etiologic pathogens, their susceptibility to antimicrobials, clinical characteristics and outcomes. Jeju is a geographically isolated and identical region in Korea. However, there is no regional reference on adult CAP available. This study investigated the etiologic agents and clinical outcomes of adult patients diagnosed with CAP in Jeju, Korea, to help guide the empirical antimicrobial choice. Methods: A prospective observational study for one year in a referral hospital in Jeju, Korea. Patients diagnosed with CAP were enrolled with their clinical characteristics. Microbiological evaluations to identify the etiologic agents in the adult patients with CAP were performed with blood culture, expectorated sputum smear and culture, antibody tests for mycoplasma, chlamydophila, and antigen tests for legionella and pneumococcus. The clinical outcomes of the initial empirical treatment were analyzed. Results: Two hundred and three patients with mean age of 64 and 79 females were enrolled. Ten microbials from 90 cases (44.3%) were isolated and multiple isolates were confirmed in 30. Among the microbial isolates, S. pneumoniae (36.3%) was the most common, followed by M. pneumoniae (23.0%), C. pneumoniae (17.0%), S. aureus (9.6%) and P. aeruginosa (5.9%). The initial treatment failure (23.8%) was related to the isolation of polymicrobial pathogens, elevated inflammatory markers, and the presence of pleural effusion. Among the 30 isolates of S. pneumoniae, 16 (53.3%) were not susceptible to penicillin, and 19 isolates (63.3%) to erythromycin and clarithromycin. However, 29 isolates (96.7%) were susceptible to levofloxacin and ceftriaxone. Conclusion: S. pneumoniae, M. pneumoniae, S. aureus, and P. aeruginosa are frequent etiologic agents of adult CAP in Jeju, Korea. The clinical characteristics and antibiotic resistance should be considered when determining the initial empirical antimicrobial choice. Respiratory quinolone or ceftriaxone is recommended as an empirical antimicrobiotic in the treatment of adult CAP in Jeju, Korea.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.304-313
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• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.920-926
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• 1998

To investigate the effects of yellow loess on the microbial community after applying into C. polykrikoides as a red tide centrol method during decomposition process, we conducted this study using microcosm experiments, which consisted of sediment collected from Jinhae and Masan bay. The composition, number of bacteria and respiratory electron transport system activity (ETSA) were analyzed. The number of heterotrophic bacteria examined in the samples of both stations reached maximum value within 12 hrs with $10^7$ cells/dry g, independent with the yellow loess applied. In addition, a differenee in the variation of heterotrophic bacterial composition was not observed by adding the yellow loess, and Vibrio spp. always appeared during the culture periods, However, in day 8 culture, the sulfate reducing bacteria was $3.8\times10^7$ cells/dry g in Masan bay and $5.5\times10^6$ cells/dry g in Jinhae bay samples without yellow loess, and these were 120, 350 fold-and 160, 420 fold-increased when yellow loess was added (1 : 1, 1 : 2). The average ETSA was 6.8$\~$7.6 $\mu$g formazan $h^{-1}$ dry $g^{-1}$ independently with yellow loess in aerobic condition for both samples, but activity was decreased by addition of yellow loess in anaerobic. Thus the addition of yellow loess to marine sediment seems to have an effect to inhibit the anaerobic decomposition process and growth of sulfate reducing bacteria which lead to the bad condition of marine environments.

• Journal of the Korean Society of Food Culture
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• v.19 no.1
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• pp.30-42
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• 2004

In order to examine the effect of the combination of fermented temperature and time on Baechu kimchi in a kimchi refrigerator, Baechu kimchi was fermented at four different modes of the fermentation temperature and time for 16 weeks and analyzed the properties of Baechu kimchi. The pH, Baechu kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ and Baechu kimchi fermented at $5^{\circ}C$ for 6 days/stored at $-1^{\circ}C$, decreased rapidly during first week and then decreased very slowly. The hardness and the chewiness of Baechu kimchi fermented at high temperature were higher and the values were decreased when the fermentation continued. In sensory evaluation, carbonated flavor in Baechu kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ was the best after 4 weeks, and Baechu kimchi fermented at $5^{\circ}C$ for 3 days or 6 days/stored at $-1^{\circ}C$ was the best after 8 weeks. The scores for sourness were the highest on 8 weeks and 12 weeks in kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ and fermented at $5^{\circ}C$ for 3 days or 6 days/stored at $-1^{\circ}C$, respectively. The sensory scores for overall acceptability were the best on 4 weeks and 8 week in kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ and fermented at $5^{\circ}C$ for 3 days or 6 days/stored at $-1^{\circ}C$, respectively. Total microbial count was increased as the temperature of fermentation increased. Counts of Leuconostoc spp. reached to the highest after 6 days and counts of Lactobacillus spp reached to the highest after 5 days in kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$. From these results, it was concluded that it required 4 weeks to eat most edible Baechu kimchi in kimchi refrigerator fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$, and 8 weeks to eat most edible Baechu kimchi in kimchi refrigerator fermented at $5^{\circ}C$ for 3 days or 6 days/stored at $-1^{\circ}C$.