• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.137-150
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• 2007

Trees emit phytoncide into atmosphere to protect them from predation. Phytoncide from different trees has its own unique fragrance that is referred to as forest bath. Phytoncide, which is essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Porphyromonas gingivalis, which is one of the most important causative agents of periodontitis and halitosis. P. gingivalis 2561 was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its cell viability, antibiotic sensitivity, morphology, and biochemical/molecular biological pattern. The results were as follows: 1. The phytoncide appeared to have a strong antibacterial effect on P. gingivalis. MIC of phytoncide for the bacterium was determined to be 0.008%. The antibacterial effect was attributed to bactericidal activity against P. gingivalis. It almost completely suppressed the bacterial cell viability (>99.9%) at the concentration of 0.01%, which is the MBC for the bacterium. 2. The phytoncide failed to enhance the bacterial susceptibility to ampicillin, cefotaxime, penicillin, and tetracycline but did increase the susceptibility to amoxicillin. 3. Numbers of electron dense granules, ghost cell, and vesicles increased with increasing concentration of the phytoncide, 4. RT-PCR analysis revealed that expression of superoxide dismutase was increased in the bacterium incubated with the phytoncide. 5. No distinct difference in protein profile between the bacterium incubated with or without the phytoncide was observed as determined by SDS-PAGE and immunoblot. Overall results suggest that the phytoncide is a strong antibacterial agent that has a bactericidal action against P. gingivalis. The phytoncide does not seem to affect much the profile of the major outer membrane proteins but interferes with antioxidant activity of the bacterium. Along with this, yet unknown mechanism may cause changes in cell morphology and eventually cell death.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.2
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• pp.136-143
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• 2013

In the sewage structures and wastewater facilities, concrete is exposed to hydrogen sulfide ($H_2S$) which acts as an acid material in a solution, and a strongly acidic sulfate ion ($SO{_4}^{-2}$) is generated by a sulfuric bacteria. Hence, a degradation of concrete with biochemical corrosion would be accelerated. Finally, durability of concrete and concrete structures may be greatly reduced. In this study, in order to remove the hydrogen sulfide which is used by the sulfuric bacteria organic-biologically, the antibiotic metal and metallic salt powders were mixed to concrete, and a suppressing performance of the sulfate ion was assessed. For the sulfuric acid bacteria, a comparative evaluation of antimicrobial performance on neutralized concrete specimens were carried out, also by a rapid chloride penetration test, chloride penetration depths and diffusion coefficients were measured for antibiotic concrete in accordance with the amount of metal and metallic salt-based antibacterial agents. Eventually, by an observation of the biochemical state of the surface of concrete specimens exposed outdoors, the performance and applicability of antibiotic concrete were confirmed.

• The Journal of Korean Medicine
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• v.31 no.4
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• pp.151-163
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• 2010

Objective: We investigated the oral malodor inhibitory effect of Scutellariae Radix (SR), Phellodendri Cortex (PC), Moutan Cortex (MTC) and Magnoliae Cortex (MGC) for the development of a gargle solution. Methods: 1. Against P. gingivalis and Pr. intermedia, the minimal bactericidal concentration (MBC) and the change of viable cells that were exposed to 1% each herbal extract were observed. 2. Deodorizing activity of 2% herbal extract and Garglin $Mint^{(R)}$ against methyl mercaptan were evaluated by gas chromatography (GC). 3. We used the salivary sediment system (SSS) as the malodor model. 4. The clinical examination was repeated 3 times by 2 subjects by $Halimeter^{(R)}$. Baseline VSC of each subject was measured. Then, the control subject gargled with cysteine for 30 sec. After 4 min, subjects would gargle for 30 seconds with herbal extracts (2%) and Garglin $Mint^{(R)}$. Subsequently, the concentration of VSC was measured at 0, 4, 8, 12, 16, 20, 40 and 60 minutes. Results: 1. Against P. gingivalis, MBC of SR, PC and MTC was 0.1%, and MBC of MGC was 1%. Removal time of P. gingivalis was as follows; 5 hr in MGC, 24 hr in SR and PC, and 48 hr in MTC. Against Pr. intermedia, MBC of SR and PC was 0.5%, and MBC of MTC, MGC was 1%. Removal time of Pr. intermedia was as follows; 5 hr in MTC and 24 hr in SR, PC and MGC. 2. Deodorizing effect of herbal extracts against methyl mercaptan was as follows; MGC and MTC had 100%, SR had 82.22%, PC had 66.60%, Garglin $Mint^{(R)}$ had 40.54%. 3. In the experiment using SSS, PC and MTC had statistically significant malodor-inhibitory effects (p<.05). 4. In the clinical examination, PC and MGC had statistically significant inhibitory effects at every elapsed time compared to the control subject. MTC had that until 40 min. SR had that at 0, 4, 8, 20, and 60 min. Conclusions: SR, PC, MTC and MGC have an antibacterial effect and the chemical removable activity of the oral malodor caused by VSC. These four herbs could have potential as effective anti-malodor agents.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.689-699
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• 2020

Brevibacillus brevis GZDF3 is a gram-positive, plant growth-promoting rhizosphere bacterium (PGPR) isolated from the rhizosphere soil of Pinellia ternata (an important herb in traditional Chinese medicine). The GZDF3 strain produces certain active compounds, such as siderophores, which are the final metabolite products of non-ribosomal peptide synthetase (NRPS) and independent non-ribosomal peptide synthetase (NIS) activity. With the present study, we attempted to investigate the siderophore production characteristics and conditions of Bacillus sp. GZDF3. The antibacterial activity of the siderophores on pathogenic fungi was also investigated. Optimal conditions for the synthesis of siderophores were determined by single factor method, using sucrose 15 g/l, asparagine 2 g/l, 32℃, and 48 h. The optimized sucrose asparagine medium significantly increased the production of siderophores, from 27.09% to 54.99%. Moreover, the effects of different kinds of metal ions on siderophore production were explored here. We found that Fe³⁺ and Cu²⁺ significantly inhibited the synthesis of siderophores. The preliminary separation and purification of siderophores by immobilized-metal affinity chromatography (IMAC) provides strong antibacterial activity against Candida albicans. The synergistic effect of siderophores and amphotericin B was also demonstrated. Our results have shown that the GZDF3 strain could produce a large amount of siderophores with strong antagonistic activity, which is helpful in the development of new biological control agents.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.77-89
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• 2015

133 Species of medicinal plants were used for the development of natural agrichemicals with anti-microbial activity against Acidovorax avenae subsp. citrulli, a pathogen of bacterial fruit blotch in watermelon. The MeOH-extracts of these medicinal plants were examined for anti-microbial activity by bioassay. The MeOH-extract of Citrus unshiu Markovich had the strongest antibacterial activity against Acidovorax avenae subsp. citrulli. To identify anti-microbial compounds from Citrus unshiu Markovich, solvent-fractionation was used. The fraction of hexane, which showing the highest value of anti-microbial activity, was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to mass database of Wiley library. As a result, d-Limonene, ${\gamma}$-terpinene, ${\beta}$-linalool, terpineol, palmitic acid, 9,12-octadecadienoic acid, Linolenic acid, and stigmasterol were identified. Among them, d-Limonene, ${\gamma}$-terpinene, ${\beta}$-linalool, and terpineol confirmed to be shown the anti-microbial activity by bioassay. Especially, d-Limonene and ${\gamma}$-terpinene found to have strong activity. In conclusion, we thought d-limonene and ${\gamma}$-terpinene from Citrus unshiu Markovich. Latin, had anti-microbial activity against Acidovorax avenae subsp. citrulli and could be candidates for the control agents for the control of bacterial fruit blotch in watermelon.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.564-570
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• 2003

The antibacterial mechanism of enterobacter Salmonella typhimurium was studied. The rfa (Waa) gene cluster of S. typhimurium encodes the core oligosaccharide biosynthesis of lipopolysaccharide (LPS). Among the rfa gene cluster, we recently cloned the rfaE gene, which is involved in ADP-L-glycero-D-manno-heptose biosynthesis. The rfaE mutant synthesizes heptose-deficient LPS, which consists of only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), thus making an incomplete LPS and a rough phenotype mutant. S. typhimurium deep-rough mutants with the heptose region of the inner core show a reduced growth rate, sensitivity to high temperature, and hypersensitivity to hydrophobic antibiotics such as baicalin isolated from the medicinal herb of Scutellaria baicalensis Georgi. Thus, in this study, the cloned rfaE gene was added to the S. typhimurium rfaE mutant strain SL1102 (rfaE543), which makes heptose-deficient LPS and has a deep-rough phenotype. The complementation created a smooth phenotype in the SL1102 strain. The sensitivity of SL1102 to bacteriophages was also recovered to that of wild-type strain, indicating that LPS is used as the receptor for bacteriophage infection. The permeability barrier of SL1102 to hydrophobic antibiotics such as novobiocin and baicalin was restored to that of the wild-type, suggesting that antibiotic resistance of the wild-type strain is highly correlated with their LPS. Through an agar diffusion assay, the growth-inhibition activity of baicalin was fully observed in the mutant SL1102 strain. However, only a half of the inhibitory activity was detected in the rfaE complemented SL1102 strain. Furthermore, the LPS produced by the rfaE-complemented SL1102 strain was indistinguishable from LPS biosynthesis of smooth strains.

• Journal of Life Science
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• v.29 no.1
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• pp.84-89
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• 2019

Previous screening of novel antibacterial agents revealed that some bacterial isolates exhibited antibiotic activity against both gram-positive and gram-negative bacteria and that they showed antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA). Among these isolates, one bacterial strain, BCNU 1204, was identified as Pseudomonas aeruginosa using phenetic and phylogenetic analysis, based on 16S ribosomal RNA gene sequences. The maximum productivities of antimicrobial substances of BCNU 1204 were obtained after being cultured at $35^{\circ}C$ and pH 7.0 for 4 d in King's medium B (KMB). Dichloromethane (DCM) and ethylacetate (EA) extracts of P. aeruginosa BCNU 1204 exhibited strong antimicrobial activity, particularly against gram-positive bacteria. The EA extracts exhibited broad-spectrum activity against antibiotic resistant strains. Fraction 5-2, was obtained by recycling preparative liquid chromatography (LC) and preparative thin-layer chromatography (TLC) and was identified as phenazine-1-carboxylic acid belonging to phenazines using gas chromatography and mass spectrometry (GC/MS). Its minimum inhibitory concentration (MIC) values were $25{\mu}g/ml$, $50{\mu}g/ml$, ${\geq}25{\mu}g/ml$, and ${\geq}50{\mu}g/ml$ for MRSA CCARM 3089, 3090, 3091, and 3095 strains, respectively. P. aeruginosa BCNU 1204 may be a potential resource for the development of anti-MRSA antibiotics. Additional research is required to identify the active substance from P. aeruginosa BCNU 1204.

• Research in Plant Disease
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• v.29 no.4
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• pp.405-413
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• 2023

Bacterial blight of carrot caused by Xanthomonas hortorum pv. carotae (Xhc) is one of the serious diseases of carrot, of which control measures has not been still established in the domestic farm. In this study, in order to select effective sterilizer for bacterial blight of carrots, three antibiotics such as streptomycin, oxolinic acid, kasugamycin, two copper compounds like copper hydroxide and copper sulfate basic and three rhizobacteria Burkholderia gladioli MRL408-3, Pseudomonas fluorescens TRH415-2 and Bacillus cereus KRY505-3 were selected to investigate their direct antibacterial effects using artificial media, aiming to identify effective pesticides against Xhc. Among them, treated medium with antibiotics such as streptomycin, oxolinic acid, and the antagonistic rhizobacteria MRL408-3 were formed inhibition zone. The agrochemicals and the rhizobacteria MRL408-3, which showed antibacterial effects on carrot leaves, pre-treated on the carrot leaves and then inoculated with Xhc. High control effects were shown on the carrot leaves pre-treated with both streptomycin and oxolinic acid. Scanning electron microscopy images of the carrot leaf surfaces showed that the population of bacteria decreased significantly on leaves pre-treated with streptomycin and oxolinic acid. From these results, it can be inferred that antibiotics like streptomycin and oxolinic acid exhibit superior control effects compared to other agents. This study provides valuable insights towards establishing an effective control system for bacterial blight of carrot.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.283-292
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• 2005

This study investigated the effects of naringin, and chitosan in rabbits' corneas. Naringin, a glycone of naringenin, is a widely distributed bioflavonoid in the grapefruit and citrus peel, and it has already been reported as an antioxidant, antimicrobial, and anticancer agent. It has been used as a food preservatives and cosmetics. One of the natural preservatives, chitosan has also used in food preservatives, health drinks, and teas. Chitosan is distributed in the epithelium of crustacea, insects, and fungi. Naringin and chitosan have no harmful effects of cytotoxicity in the human body and they are recognized as an antibacterial for various forms of bacteria. The purpose of this study is to search for the ideal percentage of natural products to substitute the chemical preservatives occuring within the cornea and conjunctiva cytotoxicity and inflammations as wearing on soft contact lens. The present study compared the morphology of corneal epithelium and endothelium observed by light microscopy (LM) and transmission electron microscopy (TEM). In vivo methods, We investigated the effects of natural preservatives on soft contact lens. We inserted 3-4 drops of the naringin and chitosan, directly on rabbits' corneas 4 times per a day during one week. After enucleation of cornea, morphorgical damages of the epithelium and endothelium were observed by LM and TEM. In view of ultrastructure, chitosan caused siginficant damage on the epithelium and endothelium of cornea. The damage of cells was higher in chitosan treated cornea than 0.01, 0.1, and 1% of naringin. The 1% of naringin also expressed cell damage seriously. The results suggest that the most important thing is to use the reasonable percentage of preservatives for contact lens solutions.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.456-464
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• 2005

Antimicrobial drug-resistance is natural response to antimicrobial stress based on selection, which weakens chemotherapy effect. Introduction of large numbers of chemotherapeutic agents to clinical practice has generated strains of microorganisms that survive and multiply in vivo with high-drug concentrations. Methicillin-resistant Staphylococcus aureus (MRSA), bacteria found in normal daily life, can be easily ingested through milk vegetables, and meats, etc. MRSA emerged in many port of the world, increasing complex clinical problems. Therefore, new agents are needed to treat MRSA. Glycyrrhiza uralensis was extracted using 80% MeOH to investigate its antimicrobial activity against MRSA stains KCCM 11812, 40510, and 40512 through bacterial measurement, disc diffusion, and O.D. methods, MIC values, MRSA gene expression investigation, and scanning electron microscope observation. Results revealed MecA, Mecl, MecRI, and FemA were the most highly manifested MRSA genes. Methanolic extract of G. uralensis significantly inhibited MRSA and thus could be used in development of antibacteria.