• Journal of Life Science
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• v.33 no.7
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• pp.538-548
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• 2023

The research has been conducted on the isolation of antimicrobial compounds from plant natural extracts and their potential application in oral health care products. This study aimed to investigate the antimicrobial mechanism by analyzing the changes in gene expression of Streptococcus mutans, a major oral pathogen, in response to complex compounds extracted from Aralia continentalis and Arctii Semen using organic solvents. Transcriptome analysis (RNA-seq) revealed that both natural extracts commonly upregulated or downregulated the expression of various genes associated with different metabolic and physiological activities. Three genes (SMU_1584c, SMU_2133c, SMU_921), particularly SMU_921 (rcrR), known as a transcription activator of two sugar phosphotransferase systems (PTS) involved in sugar transport and biofilm formation, exhibited consistent high expression levels. Additionally, component analysis of the A. continentalis extract was performed to compare its effects on gene expression changes with the A. Semen extract, and two active compounds were identified through gas chromatography-mass spectrometry (GC-MS) analysis of the active fraction. The n-hexane fraction (ACEH) from the A. continentalis extract exhibited antibacterial specificity against S. mutans, leading to a significant reduction in the viable cell counts of Streptococcus sanguinis and Streptococcus gordonii among the tested multi-species bacterial communities. These findings suggest the broad-spectrum antibacterial activity of the A. continentalis extract and provide essential foundational data for the development of customized antimicrobial materials by elucidating the antibacterial mechanism of the identified active compounds.

• Clinical and Experimental Pediatrics
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• v.61 no.5
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• pp.156-159
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• 2018

Purpose: Sepsis is a major cause of neonatal morbidity and mortality. Early diagnosis is a major problem because of the lack of specific clinical signs. Therefore, a reliable diagnostic marker is needed to guide the use of antimicrobial agents. The objective of our study was to assess the value of proadrenomedullin (pro-ADM) in establishing the diagnosis and evaluating the prognosis of neonatal sepsis. Methods: This study enrolled 60 newborn infants with sepsis proven with positive blood cultures and 30 healthy neonates. Complete blood count, C-reactive protein levels, and pro-ADM levels were obtained from all neonates. Results: The pro-ADM levels were significantly higher ($14.39{\pm}0.75nmol/L$) in the sepsis group than in the control group ($3.12{\pm}0.23nmol/L$). The optimal cutoff value for pro-ADM was 4.3 nmol/L, with a sensitivity of 93.3% and a specificity of 86.7%. The pro-ADM levels were also higher in nonsurvivors (P=0.001). Conclusion: Pro-ADM can be used as a reliable biomarker for neonatal sepsis. High pro-ADM levels were associated with mortality and could be an early indicator of disease outcome.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1166-1173
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• 2011

Meju is a traditional Korean fermented soy product used as a key element for soy sauce and doenjang. Bacilli with antimicrobial activity were isolated from meju prepared by traditional methods at Sunchang county, Jeollabukdo, Korea. Six isolates were identified as Bacillus amyloliquefaciens by recA gene sequencing and RAPD-PCR. One isolate, B. amyloliquefaciens MJ5-41, showed the strongest fibrinolytic activity. A 27 kDa active fibrinolytic enzyme, AprE5-41, was purified from the culture supernatant of MJ5-41 grown on LB by chromatographic methods. The optimum pH and temperature for purified AprE5-41 were 7.0 and $45^{\circ}C$, respectively. AprE5-41 quickly degraded $A{\alpha}$ and $B{\beta}$ chains but not the ${\gamma}$-chain of fibrinogen. AprE5-41 exhibited the highest specificity for N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a known substrate for ${\alpha}$-chymotrypsin, cathepsin G, and subtilisin BPN'. The structural gene, aprE5-41, was cloned by PCR and successfully expressed in B. subtilis.

• Journal of Life Science
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• v.22 no.8
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• pp.1114-1119
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• 2012

Bacteria are frequently contaminated during the collection and processing procedures of boar semen. Of the contaminants, Stenotrophomonas (S.) maltophilia is a Gram-negative bacterium that is widely distributed in a variety of habitats. Although PCR assays have been developed for the detection of S. maltophilia, they cross-react with some species of Xanthomonas. In this study, we designed a primer set for the detection of S. maltophilia in order to target the chiA (GenBank accession no. NC_010943) gene. The specific PCR products were amplified from S. maltophilia only, not from other tested strains that are frequently found in semen. The detection limit of the PCR was $1.5{\times}10^3$ CFU/ml with pure-cultured S. maltophilia and $1.5{\times}10^4$ CFU/ml with S. maltophilia spiked in semen. Twenty-six (5.9%) S. maltophilia were isolated from 440 semen samples. The PCR results exhibited 98.9% agreement with a comparison of S. maltophilia isolation. Also, the sensitivity and specificity of the PCR were 100% and 98.7%, respectively. In the antimicrobial susceptibility test, S. maltophilia isolates were highly susceptible to enrofloxacin and florfenicol, while the majority of them were resistant to amoxicillin/clavulanic acid, apramycin, ceftiofur, penicillin, and spectinomycin. These results indicated that the PCR using the chiA gene was proven to be reliable and effective for the detection of S. maltophilia with high levels of sensitivity and specificity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.37-44
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• 2014

Preservatives such as paraben, phenoxyethanol, and chlorphene are commonly used in cosmetics thanks to cheap price and good antiseptic effect. Recently, consumers' concerns about their possible toxicity and skin irritation forced them to be replaced with straight 1,2-alkanediols. However, as the alkanediols may also irritate skin, limited amount of them should be used in cosmetics. Three 1,2-alkanediols including 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol in cosmetics were analyzed simultaneously by gas chromatogrphy with flame ionization detector. As a result of method validation, the specificity was confirmed by the calibration curves of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol showing good linearity correlation coefficient of above 0.999 over the concentration range of $100{\sim}1,200{\mu}g/g$. The limit of detection (LOD) and quantification (LOQ) of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol were 31, 40, and $19{\mu}g/g$ and 98, 108, and $57{\mu}g/g$, respectively. The precision (Repeatability) of the amount in cosmetics showed less than 2.0%. Relative Standard Deviation (% RSD) and the Accuracy (% recovery) of the amount in cosmetics showed 99.3 ~ 103.3, 99.4 ~ 106.7, 97.5 ~ 107.3% respectively. As a result, simultaneous analysis of antimicrobial three 1,2-alkanediols in cosmetics were possible. This method can be utilized in accurate quantitative analysis of 1,2-alkanediols in cosmetics.

• Korean Journal of Veterinary Service
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• v.22 no.3
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• pp.221-237
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• 1999

To investigate the specificity of rapid slide agglutination test for pullorum-gallinarum diseases and to obtain a basic data for avian salmonellosis control, salmonella isolation was peformed for the layer chickens positively reacted in pullonlm-typhoid agglutination test. The biochemical, serological and antimicrobial properties of the isolates were examined. The results obtained through this study were summarized as follows; 1. Of 2,384 chickens tested by the agglutination test, 606 chickens (25.4%) were positive reactors. 154 of 606 reactors and 49 of the non-reacting chickens were investigated for salmonella isolation, resulting in isolation of 68 strains of salmonellae from 27 chickens. 2. By organs, the isolation frequency from liver, cecum, spleen, ovary and gall bladder showed 8.9% (18 strains), 8.9% (18 strains), 7.4% (15 strains), 4.4% (9 strains) and 3.9% (8 strains), respectively. 3. By culture medium the combination of selenite broth and MacConkey agar revealed the highest isolation rate and the enrichment culture by delayed secondary enrichment culture method was found the most effective for salmonella isolation. 4. The serotypes of 68 salmonella isolates were identified as 3 strains of S pullorum, 24 strains of S gallinarum, 15 strains of S typhimurium, 8 strains of S enteritidis, 7 strains of S paratyphi A, 5 strains of S typhimurium and 6 strains of the other salmonellae. 5. The serotypes of 8 salmonella strains isolated from 49 chickens non-reacting in pullorum-typhoid agglutination test were identified as 3 strains of S typhimurium and 5 strains of S infantis. 6. When 24 chickens of which 68 strains of salmonellae isolated were examined by microplate agglutination test, the average antibody titer for pullorum antigen was $2^{5.25}$. The chickens at antibody titer between $2^3$ and $2^5$ showed the higher frequency of isolation as compared with the chickens at the other titers. 7. When salmonella isolates were tested the antimicrobial drug sensitivity by disk diffusion method, S paratyphi A were highly sensitive by 100% to ATM and GM, S typhimurium, by 88% to AM, CIP, IMP and TN, S infantis, by 100% to AM, CRO, ENR and PIP, S enteritidis,by 100% to IMP and PIP, S pullorum, by 100% to ATM, CRO, ENR and PIP and S gallinarum, by 92% to CRO, CIP and PIP.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.194-198
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• 2015

Enterococcus faecalis is a Gram-positive and facultative anaerobic bacterium that causes many hospital-acquired infections. Novel E. faecalis specific bacteriophage (phage) ECP3 that had been isolated from thirty-four environmental samples and characterized phenotypically and genotypically. ECP3 phage belongs to the family Myoviridae with contractile tail and lysed E. faecalis specifically but other bacteria including Enterococcus faecium. The genome was double-stranded linear DNA and its size was 145,518 bp comprising of 220 open reading frames. The GC content was 35.9%. The genome sequence showed 97% identity in 90% coverage region with Myoviridae phage PhiEF24C. ECP3 is the first E. faecalis-specific Myoviridae phage isolated in Korea which can be a promising antimicrobial agent against E. faecalis infections.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1335-1340
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• 2007

β-Ketoacyl acyl carrier protein synthase (KAS) III is a particularly attractive target in the type II fatty acid synthetic pathway, since it is central to the initiation of fatty acid synthesis. Enterococcus faecalis, a Grampositive bacterium, is one of the major causes of hospital acquired infections. The rise of multidrug-resistant of most bacteria requires the development of new antibiotics, such as inhibition of the KAS III. In order to block the fatty acid synthesis by inhibition of KAS III, at first, three dimensional structure of Enterococcus faecalis KAS III (efKAS III) was determined by comparative homology modeling using MODELLER based on x-ray structure of Staphylococcus aureus KAS III (saKAS III) which is a gram-positive bacteria and is 36.1% identical in amino acid sequences with efKAS III. Since His-Asn-Cys catalytic triad is conserved in efKAS III and saKAS III, substrate specificity of efKAS III and saKAS III and the size of primer binding pocket of these two proteins are expected to be similar. Ligand docking study of efKAS III with naringenin and apigenin showed that naringenin docked more strongly with efKAS III than apigenin, resulting in the intensive hydrogen bond network between naringenin and efKAS III. Also, only naringenin showed antibacterial activity against E. faecalis at 256 μg/mL. This study may give practical implications of flavonoids for antimicrobial effects against E. faecalis.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1131-1136
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• 2013

Parabens, the esters of p-hydroxybenzoic acid, have been widely used as antimicrobial preservatives in cosmetic products, drugs, and processed foods and beverages. However, some parabens have been shown to have weak estrogenic effects through in vivo and in vitro studies. Because such widespread use has raised concerns about the potential human health risks associated with exposure to parabens, we developed a simultaneous analytical method to quantify 4 parabens (methyl, ethyl, propyl, and butyl) in human urine, by using solid-phase extraction and high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. This method showed good specificity, linearity ($R^2$ > 0.999), accuracy (92.2-112.4%), precision (0.9-9.6%, CV), and recovery (95.7-102.0%). The LOQs for the 4 parabens were 1.0, 0.5, 0.2, and 0.5 ng/mL, respectively. This method could be used for quick and accurate analysis of a large number of human samples in epidemiological studies to assess the prevalence of human exposure to parabens.

• Clinical and Experimental Pediatrics
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• v.46 no.8
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• pp.758-762
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• 2003

Purpose : Our examination was designed to determine the diagnostic properties of the cutoff point for the prediction of bacteremia in febrile children less than 3 years of age. Cutoff point is the value that simultaneously maximizes both sensitivity and specificity. Methods : We conducted a retrospective study of febrile children, less than 3 years of age, who clinically have no identifiable source of fever. Peripheral blood leukocyte count(WBC), absolute neutrophil count(ANC), erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) were measured at the same time. All patients received blood culture, urine culture and/or CSF culture. Bacterial infection was defined as single pathogen isolated from the CSF or blood or a urinary tract infection (UTI). Patients were dichotomized into two groups : those with bacterial infection and no bacterial infection. We analyzed the characteristics of the children in the two groups. Results : Seventy-one patients(44 males; 27 females) were enrolled in the study. Twenty patients (28%) had a serious bacterial infection(twelve urinary tract infection, five bacteremia, three meningitis) and fifty-one(72%) had no serious bacterial infection. WBC, ESR and CRP were significantly different between the two groups(P<0.05). The cutoff point of WBC, ESR and CRP were $20,000/mm^3$, 30 mm/hr and 3.0 mg/dL, respectively. The sensitivity and specificity of each cutoff point were WBC(75%, 75%), ESR(79%, 68%) and CRP(83%, 77%), respectively. Conclusion : These data show the ability of predictors to identify febrile children less than 3 years of age with bacterial infection. Febrile children who reach the cutoff point must be treated intensively and those who do not reach the cutoff point can be carefully managed without administering antimicrobial agents.