• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.385-393
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• 2016

Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50℃, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits.

• Journal of Integrative Natural Science
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• v.10 no.1
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• pp.1-6
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• 2017

Demand for a new anti-malarial drug has been dramatically increasing in the recent years. Plasmodium falciparum enoyl-acyl carrier protein reductase (PfENR) plays a vital role in fatty acid elongation process, which now emerged as a new important target for the development of anti-microbial and anti-parasitic molecules. In the present study, 19 compounds namely alginic acid, atropine, chlorogenic acid, chrotacumine A & B, coenzyme $Q_1$, 4-coumaric acid, curcumin, ellagic acid, embelin, 5-O-methyl embelin, eugenyl glucoside, glabridin, hyoscyamine, nordihydroguaiaretic acid, rohitukine, scopolamine, tlatlancuayin and ursolic acid were evaluated on their docking behaviour on P. falciparum enoyl-acyl carrier protein reductase (PfENR) using Auto dock 4.2. The docking studies and binding free energy calculations exhibited that glabridin gave the highest binding energy (-8.07 kcal/mol) and 4-coumaric acid in contrast showed the least binding energy (-4.83 kcal/mol). All ligands except alginic acid, ellagic acid, hyoscyamine and glabridin interacted with Gln409 amino acid residue. Interestingly four ligands namely coenzyme $Q_1$, 4-coumaric acid, embelin and 5-O-methyl embelin interacted with Gln409 amino acid residue present in both chains (A & B) of PfENR protein. Thus, the results of this present study exhibited the potential of these 19 ligands as P. falciparum enoyl-acyl carrier protein reductase (PfENR) inhibitory agents and also as anti-malarial agents.

• Journal of Microbiology
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• v.43 no.5
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• pp.463-468
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• 2005

Studying the bacteria of hazardous insects allows the opportunity to find potentially better biological control agents. Therefore, in this study, bacteria from summer chafer (Amphimallon solstitiale L., Coleoptera: Scarabaeidae) we isolated and identified the insecticidal effects of bacteria isolated from A. solstitiale and Melolontha melolontha L. (common cockchafer, Coleoptera: Scarabaeidae) and the mixtures of these bacterial isolates were investigated on A. solstitiale larvae. Crystals from Bacillus sp. isolated from M. melolontha were also purified, and tested against the second and third-stage larvae of A. solstitiale. The bacterial isolates of A. solstitiale were identified as Pseudomonas sp., Pseudomonas sp., Bacillus cereus and Micrococcus luteus, based on their morphology, spore formation, nutritional features, and physiological and biochemical characteristics. The insecticidal effects of the bacterial isolates determined on the larvae of A. solstitiale were $90\%$ with B. cereus isolated from A. solstitiale, and $75\%$ with B. cereus, B. sphaericus and B. thuringiensis isolated from M. melolontha within ten days. The highest insecticidal effects of the mixed infections on the larvae of A. solstitiale were $100\%$ both with B. cereus+B. sphaericus and with B. cereus+B. thuringiensis. In the crystal protein bioassays, the highest insecticidal effect was $65\%$ with crystals of B. thuringiensis and B. sphaericus isolated from M. melolontha within seven days. Finally, our results showed that the mixed infections could be utilized as microbial control agents, as they have a $100\%$ insecticidal effect on the larvae of A. solstitiale.

• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.225-232
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• 2000

Purpose : The use antimicrobial agents is one of the important strategies for the treatment and prophylaxis of microbial infections. But injudicious abuse and misuse of antimicrobial agents is problem to add an extra weight on medical fee, increase of resistant bacteria and side effects according to the antibiotic use. This study was performed to establish the pertinent use of antimicrobial agent in Chonbuk National University Hospital(CNUH). Characteristics of antibiotics use was analysis by reviewing the medical records of patients admitted to CNUH during the period of May 1998. Methods : One thousand eight hundred and thirty three patients were enrolled in this study(medical division 1,014 cases, surgical division 819 cases). Medical records were retrospectively reviewed to classify the rate of antibiotics use, name of antibiotics used, appropriateness of antibiotics use. Results : The overall rate of antibiotic usage in CNUH was 67.2%(1,231/1,833), showing higher rate in surgical division(89.6%) compare to that of medical division(49.0%). Among 1,231 patients to whom antimicrobial agents were given, only 125(10.2%) were treated with single antimicrobial agents. 311(25.3%) were treated with two antimicrobial agents, and 795(64.5%) patients received 3 or more antibiotics. ${\beta}$-lactams(56.4%) were most frequently used followed by aminoglycosides(35.3%), the others(4.9%) and quinolons(3.4%). Amoxicillin-clavulanate was the mostly commonly used antibiotics followed by amoxicillin and unasyn. Prophylactic use of antibiotics was carried in seven hundred six patients(57.4%), mostly in surgical division, which can be considered somewhat inappropriate in the initiation time and duration of antibiotic use. Conclusion : Importance of monotherapy and appropriate prophylactic antibiotic use should be emphasized. Strategies of antibiotics use, such as restriction of drug use, continuous monitoring system, flow sheet system should be considered to reduce antibiotics use and establish the appropriate use of antibiotics as well as inhibiting the occurrence of resistant strains.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.435-445
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• 2008

Due to internal feeding behavior, the oriental tobacco budworm, Helicoverpa assulta ($Guen\acute{e}e$), infesting hot pepper has been regarded to be effectively controlled by targeting egg and neonate larval stages just before entering the fruits. This study aimed to develop an efficient biological control method focusing on these susceptible stages of H. assulta. An egg parasitoid wasp, Trichogramma evanescens Westwood, was confirmed to parasitize the eggs of H. assulta. A mixture of Gram-positive soil bacterium, Bacillus thuringiensis subsp. kurstaki, and Gram-negative entomopathogenic bacterium, Xenorhabdus nematophila ANU101, could effectively kill neonate larvae of H. assulta. A sex pheromone trap monitored the occurrence of field H. assulta adults. The microbial insecticide mixture was proved to give no detrimental effects on immature development and adult survival of the wasp by both feeding and contact toxicity tests. A combined treatment of egg parasitoid and microbial pesticide was applied to hot pepper fields infested by H. assulta. The mixture treatment of both biological control agents significantly decreased the fruit damage, which was comparable to the chemical insecticide treatment, though either single biological control agent did not show any significant control efficacy. This study also provides morphological and genetic characters of T. evanescens.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1715-1719
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• 2004

In order to help the preservation of the unshiu orange and pear, antimicrobial paper incorporating grapefruit seed extract and zeolite was applied to pack fruits. Unshiu orange was packed in a box (24${\times}$24${\times}$22 cm) attached with antimicrobial paper and then stored respectively at l$0^{\circ}C$. Pears were wrapped individually before storage at l$0^{\circ}C$. During the storage, weight loss, pH, total acidity, soluble solid content, microbial load and decay were measured as quality indices. Steady pH increase in unshiu orange was observed to slightly decrease total acidity during the storage with little difference between the packaging treatments. The microbial loads of total aerobic bacteria, and yeast/mold counts were suppressed during storage by the antimicrobial paper packaging, which also contributed to reducing the decayed unshiu orange. Limited reduction of total aerobic bacteria and yeast/mold counts was observed only for initial storage period for the pears wrapped with 9 and 12% antimicrobial agent-added papers. Antimicrobial paper was useful for the reduction of microbial load in unshiu orange and pear without other quality deterioration.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.20-28
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• 2009

The sustainability of conventional agriculture which is characterized by input dependent and ecologically simplified food production system is vague. Chemicals and present practices used in agriculture are not only costly but also have widespread implications on human and animal health, food quality and safety and environmental quality. Thus there is a need for alternative farming practices to sustain food production for the escalating population and conserve environment for future generations. The present research scenario in the area of plant microbe interactions for maintaining sustainable agriculture suggests that the level of internal regulation in agro-ecosystems is largely dependent on the level of plant and microbial diversity present in the soil. In agro-ecosystems, biodiversity performs a variety of ecological services beyond the production of food, including recycling of nutrients, regulation of microclimate and local hydrological processes, suppression of undesirable organisms and detoxification of noxious chemicals. Controlling the soil microflora to enhance the predominance of beneficial and effective microorganisms can help improve and maintain soil chemical and physical properties. The role of beneficial soil microorganisms in sustainable productivity has been well construed. Some plant bacteria referred to as plant growth-promoting rhizobacteria (PGPR) can contribute to improve plant growth, nutrient uptake and microbial diversity when inoculated to plants. Term PGPR was initially used to describe strains of naturally occurring non-symbiotic soil bacteria have the ability to colonize plant roots and stimulate plant growth PGPR activity has been reported in strains belonging to several other genera, such as Azotobacter, Azospirillum, Arthrobacter Bacillus, Burkhokderia, Methylobacterium, and Pseudomonas etc. PGPR stimulate plant growth directly either by synthesizing hormones such as indole acetic acid or by promoting nutrition, for example, by phosphate solubilization or more generally by accelerating mineralization processes. They can also stimulate growth indirectly, acting as biocontrol agents by protecting the plant against soil borne fungal pathogens or deleterious bacteria. Present review focuses on some recent developments to evolve strategies for better biotechnological exploitation of PGPR's.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.304-311
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• 2012

Chlorinated ethylenes such as perchloroethylene (PCE) and trichloroethylene (TCE) are widely used as industrial solvents and degreasing agents. Because of improper handling, these highly toxic chlorinated ethylenes have been often detected from contaminated soils and groundwater. Biological PCE dechlorination activities were tested in bacterial cultures inoculated with 10 different environmental samples from sediments, sludges, soils, and groundwater. Of these, the sediment using culture (SE 2) was selected and used for establishing an efficient PCE dechlorinating enrichment culture since it showed the highest activity of dechlorination. The cathode chamber of bioelectrochemical system (BES) was inoculated with the enrichment culture and the system with a cathode polarized at -500 mV (Vs Ag/AgCl) was operated under fed-batch mode. PCE was dechlorinated to ethylene via TCE, cis-dichloroethylene, and vinyl chloride. Microbial community analysis with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) showed that the microbial community in the enrichment culture was significantly changed during the bio-electrochemical PCE dechlorination in the BES. The communities of suspended-growth bacteria and attached-growth bacteria on the cathode surface are also quite different from each other, indicating that there were some differences in their mechanisms receiving electrons from electrode for PCE dechlorination. Further detailed research to investigate electron transfer mechanism would make the bioelctrochemical dechlorination technique greatly useful for bioremediation of soil and groundwater contaminated with chlorinated ethylenes.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.3
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• pp.205-213
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• 2013

This study was to improve cosmetical activity of thiamine di-lauryl sulfate (TDS) by encapsulation of nanoparticle with lecithin. Results showed that most of the nanoparticles containing the TDS were well formed in round shape with below 150 ~ 200 nm diameter as well as they were fairly stable in various pH ranges by measuring zeta potentials. The nanoparticles of TDS resulted in 85% cell viability of human normal fibroblast cells (CCD-986sk) when added at the highest concentration (1.0 mg/mL). The nanoparticles of Acer mono sap showed highest free radical scavengering effect as 88.1% in adding sample (1.0 mg/mL), compared to TDS solution of non-encapsulation (81.6%). The nanoparticles of TDS reduced the expression of MMP-1 on UV-irradiated CCD-986sk cells down to as 41.4%. The TDS solution and nanoparticles showed significant anti-microbial activities agaionst the salmonella typhimurium and listeria monocytogenes at 5 and 6 days as compared with control. Anti-microbial activities of TDS nanoparticles were similar to positive control. These results indicated that TDS nanoparticles may be a source for functional cosmetic agents capable of improving cosmetical activity such as antioxidant, whitening, and anti-wrinkling effects and can be further developed as natural preservative in cosmetics.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.576-586
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• 2021

The purpose of this study was to evaluate the antifungal activity, plant-growth-promoting activity, and mineral solubilization ability of 10 species of phytopathogenic fungi to select a Bacillus sp. from rhizosphere soils and roots that can be used as a microbial agent. The antifungal activity for phytopathogenic fungi varied based on the Bacillus sp. Among the selected strains, DDP4, DDP16, DDP148, SN56, and SN95 exhibited antifungal activity for nine or more species of phytopathogenic fungi. Regarding nitrogen-fixation ability, all Bacillus sp. showed similar levels of activity, and siderophore production ability was relatively high in ANG42 and DDP427. The indole-3-acetic acid production abilities were in the range of 1.83-67.91 ㎍/ml, with variations in activity based on the Bacillus sp. One strain with a high activity was selected from each species, and their mineral solubilization abilities were examined. Most Bacillus sp. could solubilize phosphoric acid and calcium carbonate, and DDP148 and SN56 could solubilize silicon and zinc, respectively. These results suggested that Bacillus sp. can be considered potential multi-purpose microbial agents for plant growth promotion and disease prevention.