• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.210-215
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• 2018

Objectives: The main objectives of this study were to verify the antibacterial activity of two essential oils, lavender and peppermint, against dental caries and to review their synergistic effect when used in combination. Our results provide basic data for the evaluation of the use of these two substances towards the prevention and cure of dental caries. Methods: The sample solutions of lavender and peppermint oils were prepared in three different concentrations (30%, 50%, and 70% (v/v)) by diluting them with third-distilled water and Tween 20. Streptococcus mutans was selected as the bacterial species for testing. The disk diffusion method was used to measure the antibacterial activity of the sample solutions. For generating growth curves and measuring the number of clusters of the bacterial, the liquid medium-dilution method was used; the absorbance of the medium was measured at 600 nm after 3, 6, 12 and 24 hours. Results: When the antibacterial activity of the oils was tested via the disk diffusion method, the activity improved with increasing concentrations of all the sample solutions of peppermint, lavender, and the blend, but there was no significant difference between them with respect to the type of oil. In the growth curves of S. mutans, growth inhibition was observed after 12 hours. The inhibitory effect of 30% lavender oil on growth was 64.9% and 80.1% after 12 and 24 hours of treatment, respectively whereas that of peppermint oil was 71.3% and 80.1% after 12 and 24 hours of treatment, respectively. The inhibitory effect of the blended oil was 71.9% and 81.0% after 12 and 24 hours of treatment, respectively. Conclusions: Further research is still required in order to determine the efficacy of lavender and peppermint oils, as well as other essential oils, for wider use in preventing dental caries.

• Research in Plant Disease
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• v.28 no.2
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• pp.69-81
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• 2022

This study was performed to screen the efficacy of antagonistic bacterial isolates from various sources against the bacterial fruit blotch (BFB) causing pathogen (Acidovorax citrulli) in cucurbit crops. In addition, plant growth promoting traits of these antagonistic bacterial isolates were characterized. Two thousand seven hundred ninety-four microorganisms were isolated from the collected samples. Molecular identification revealed two A. citrulli out of 2,794 isolates. In vitro antagonistic results showed that, among the 28 antagonistic bacterial isolates, 24 and 14 bacterial isolates exhibited antagonism against HPP-3-3B and HPP-9-4B, respectively. Antagonistic and growth promotion characterization of the antagonistic bacterial isolates were further studied. Results suggested that, 4 antagonistic bacteria commonly showed both antagonism and growth promotion phenotypes. Moreover, 3 isolates possessed growth promoting activities. Overall results from this study suggests that BFB causing bacterial pathogen (A. citrulli) was suppressed in in vitro antagonism assay by antagonistic bacterial isolates. Furthermore, these antagonistic bacterial isolates possessed growth promotion and antagonistic enzyme production ability. Therefore, data from this study can provide useful basic data for the in vivo experiments which ultimately helps to develop the eco-friendly agricultural materials to control fruit rot disease in cucurbit crops in near future.

• Journal of Microbiology
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• v.35 no.4
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• pp.284-289
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• 1997

A Gram (-), rod-shaped bacterium $2.3{\sim}2.8{\times}0.45{\mu}m$ in size which exhibited growth-inhibiting effects against a cyanobacterium (Anabaena cylindrica) was isolated from Daechung Dam Reservoir. This isolate was identified as Moraxella sp. and designated Moracella sp. CK-1. Hollow zones formed around bacterial colonies on the cyanobacterial lawn. In a mixed-culture of A. cylindrica and the isolate, each microorganism grew inverse-proportionally, and the cyanobacterial vegetative cells completely disappeared within 24 hours. On treatment with Moraxella sp. CK-1, cell walls of A. cylindrica disappeared, but sheathes remained in a more electron dense form. The unit membrane such as thylakoidal membrane was stable to bacterial lysing activity. This bacterium showed a broad action spectrum against cyanobacteria. The growth-inhibiting activity of Moracella sp. CK-1 against A. cylindrica is believed to be performed through the excretion of active substances.

• The Korean Journal of Ecology
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• v.16 no.3
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• pp.275-285
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• 1993

To study allelopathic porential of naturally occurring substances emitted from Pinus koraiensis, the effects of water exrracts and volatile substances of the tree on callus induction and bacterial culture were examined. The induction and growth of callus were inversely proportional to the concentration of the extracts and of the essential oils supplemnted to Murashige and Skoog's media. However, low concentration(5μl/l) of essential oil promoted callus growth. In germiculture of several bavteria, the extracts of Pinus koraiensis markedly showed the inhibitory effects on bacterial growth. It was, therefore, confirmed that the KDICical substances of Pinus koraiensis tree clearly showed that biological toxic activity at high concentrations.

• Korean Journal of Organic Agriculture
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• v.11 no.4
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• pp.61-74
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• 2003

This study was conducted to screen the antagonistic bacteria which inhibit the growth of plant pathogen, fusarium wilt(Fusarium oxysporum) occurred in tomato plants in greenhouse. We isolated an effective bacterial strains and investigated into the antifungal activity of the antagonistic microorganism and it’s identification. Ten bacterial strains which strongly inhibited Fusarium oxysporum were isolated from the nature, and the best antagonistic bacterial strain designated as KC175, was selected. The antagonistic strain KC175 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. The Bacillus sp. KC175 showed 58.2% of antifungal activity against the growth of Fusarium oxysporum. By the bacterialization of the culture broth and the heat bacterialization culture filtrate of it, Bacillus sp. KC175 showed 91% and 18% of antifungal activity, respectively.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.18-24
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• 1994

Multiplications and pathogenic reactions of different pepper and tomato strains of Xanthomonas campestris pv. vesicatoria were evaluated in the most upper leaves of pepper and tomato plants at different growth stages. Hypersensitive reactions were induced in mature pepper plants by inoculation with only the tomato strains but not with the pepper strains, suggesting the expression of age-related resistance in pepper plants. The age-related resistance also seems to be correlated with an apparent inability of the bacteria to multiply as extensively in mature as in young plants. No significant differences among the Korean and U. S. pepper cultivars tested were found in bacterial multiplication, irrespective of bacterial stain or plant growth stage. Korean tomato cultivars tested also were highly susceptible to either tomato or pepper strains during the development of tomato plants.

• Biomedical Science Letters
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• v.29 no.2
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• pp.88-94
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• 2023

In oriental medicine, the fruit of Actinidia polygama has long been used to alleviate the symptoms of gout, arthritis, and inflammation. In this study, it was to designed to analyze the antibacterial activity of A. polygama ethanol extract (APEE) against Streptococcus mutans, one of the major strains for dental caries, and Porphyromonas gingivalis, one of the critical strains for periodontal disease. The antibacterial activity of APEE was analyzed by disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. In addition, it was also analyzed the inhibitory effect of APEE on bacterial growth and biofilm formation against both oral pathogens. APEE exhibited its antibacterial effect through the inhibited bacterial diffusion as well as low concentration of MIC and MBC. In addition, APEE significantly inhibited not only bacterial growth but also biofilm formation in a dose-dependent manner. Consequently, APEE showed potent antibacterial activity against both S. mutans and P. gingivalis, which indicates that APEE might be used as a potential antibacterial material for the improvement of oral healthcare.

• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.157-161
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• 2018

The objective of this study was to develop software to predict the kinetic behavior and the probability of foodborne bacterial growth on processed meat products. It is designed for rapid application by non-specialists in predictive microbiology. The software, named Foodborne bacteria Animal product Modeling Equipment (FAME), was developed using Javascript and HTML. FAME consists of a kinetic model and a probabilistic model, and it can be used to predict bacterial growth pattern and probability. In addition, validation and editing of model equation are available in FAME. The data used by the software were constructed with 5,400 frankfurter samples for the kinetic model and 345,600 samples for the probabilistic model using a variety of combinations including atmospheric conditions, temperature, NaCl concentrations and $NaNO_2$ concentrations. Using FAME, users can select the concentrations of NaCl and $NaNO_2$ meat products as well as storage conditions (atmosphere and temperature). The software displays bacterial growth patterns and growth probabilities, which facilitate the determination of optimal safety conditions for meat products. FAME is useful in predicting bacterial kinetic behavior and growth probability, especially for quick application, and is designed for use by non-specialists in predictive microbiology.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.253-259
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• 2015

Anthracnose caused by Collectotrichum acutatum is the most devastating disease of pepper plants in Korea. In this study, we evaluated the effect of selected antagonistic bacteria on control of anthracnose and plant growth promotion of pepper plants under field conditions. Four different bacterial isolates used in the current study were isolated from the pepper rhizosphere (GJ01, GJ11) and tidal flat (LB01, LB14) in previous studies. Four bacterial isolates, together with a control strain (EXTN-1), showed antifungal activity against C. acutatum in a dual culture assay. To test for plant growth promotion effect, seedling vigor index and growth parameters of pepper were measured under field condition. As a result, all four bacterial isolates were effective for improving plant growth promotion. The strain GJ01 was the most effective in improving the seedling vigor on pepper, but the strain GJ11 in increasing the pepper fruit yield. The incidence of anthracnose was inhibited in the range of 63.2~72.5% by treatment of four bacterial isolates. The current study indicated that the four bacterial isolates could be used as potential biological control agents of anthracnose disease of pepper.

• Animal Bioscience
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• v.37 no.2
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• pp.261-273
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• 2024

Objective: The objective of this study was to evaluate the growth performance, rumen fermentation parameters and bacterial community of post-weaning dairy calves in response to five diets varying in corn silage (CS) inclusion. Methods: A total of forty Holstein weaned bull calves (80±3 days of age;128.2±5.03 kg at study initiation) were randomized into five groups (8 calves/group) with each receiving one of five dietary treatments offered as total mixed ration in a 123-d feeding study. Dietary treatments were control diet (CON; 0% CS dry matter [DM]); Treatment 1 (T1; 27.2% CS DM); Treatment 2 (T2; 46.5% CS DM); Treatment 3 (T3; 54.8% CS DM); and Treatment 4 (T4; 67.2% CS DM) with all diets balanced for similar protein and energy concentration. Results: Results showed that calves offered CS had greater average daily gain, body length and chest depth growth, meanwhile altered rumen fermentation indicated by decreased rumen acetate concentrations. Principal coordinate analysis showed the rumen bacterial community structure was affected by varying CS inclusion diets. Bacteroidetes and Firmicutes were the predominant bacterial phyla in the calf rumens across all treatments. At the genus level, the abundance of Bacteroidales_RF16_group was increased, whereas Unclassified_Lachnospiraceae was decreased for calves fed CS. Furthermore, Spearman's correlation test between the rumen bacteria and rumen fermentation parameters indicated that Bacteroidales_RF16_group and Unclassified Lachnospiraceae were positively correlated with propionate and acetate, respectively. Conclusion: The results of the current study suggested that diet CS inclusion was beneficial for post-weaning dairy calf growth, with 27.2% to 46.5% CS of diet DM recommended to achieve improved growth performance. Bacteroidales_RF16_group and Unclassified Lachnospiraceae play an important role in the rumen fermentation pattern for post-weaning calves fed CS.