• 미생물학회지
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• 제55권3호
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• pp.258-267
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• 2019

본 연구의 목적은 탈지유와 두유 내에서 Enterobacter aerogenes CIH05의 증식과 바이오제닉 아민(biogenic amines, BA) 생성량에 대한 유산균의 영향을 조사하는 것이다. 갓김치로부터 분리된 Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74 및 Lactobacillus planatrum GK81은 탈카르복시화 배지 상에서 BA를 생성하지 않았다. 탈지유와 두유 내에서 L. paracasei GK74에 의해 가장 많은 생균수와 항균 물질 생성량이 측정되었고, 반면 L. plantarum GK81은 다른 균주들에 비해 유의하게 낮은 균수와 항균 물질을 생산하였다. 유산, 과산화수소 및 박테리오신의 생산량은 Lactobacillus의 균종과 배지 종류에 의존하였다. 유산균과 유사하게 E. aerogenes CIH05도 단독 배양 시 두유보다 탈지유에서 더 많은 균수가 측정되었다. 탈지유와 두유 내에서 L. acidophilus GK20이나 L. paracasei GK74와 혼합 배양하거나 박테리오신 용액(300 AU/ml)을 처리했을 때 E. aerogenes CIH05의 균수가 유의하게 감소되었고 히스타민과 카다베린의 생성도 효과적으로 억제되었다.

• Journal of Applied Biological Chemistry
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• 제62권1호
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• pp.19-23
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• 2019

수증기증류 추출법에 의한 미국산 길초근(Valeriana officinalis)의 구성성분을 알아보기 위해 GC-MS 분석을 수행한 결과, 주요 성분이 patchouli alcohol (18.69%) 및 ${\beta}$-gurjunene (15.26%)인 것으로 나타났다. 그리고 길초근 정유의 살비활성 및 항균활성을 알아보기 위해 작은소피참진드기 및 긴털가루응애에 대하여 접촉독성법을 실시하였고, 식중독균 8 종에 대하여 agar disc diffusion법을 실시하였다. 그 결과, 긴털가루응애 성충에 대하여 $28.01{\mu}g/cm^2$의 $LD_{50}$값을 나타내었으며, 작은소피참진드기 유충 및 약충에 대하여 각각 178.26 및 $207.98{\mu}g/cm^2$의 $LD_{50}$ 값을 나타내었다. 또한 식중독균은 8종 균주에 대하여 항균활성을 나타내었으며, 특히 L.monocytogenes에 대하여 우수한 항균활성을 나타내었다. 따라서 본 연구를 통해 수증기증류 추출법에 의한 길초근 정유가 살비제 및 항생제로서의 가치가 있음을 확인하였다.

• 한국축산식품학회지
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• 제39권3호
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• pp.418-429
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• 2019

This study was conducted to evaluate the antioxidant and antimicrobial activities of lyophilized extracts of scallions (Allium fistulosum L., SLE), garlic (Allium sativum, GLE), and gold kiwi (Actinidia chinensis, GKE) and their effects on the quality of chicken breast meat inoculated with L. monocytogenes during storage for 9 days at $4^{\circ}C$. The lowest minimum inhibitory concentration and minimum bactericidal concentration (25 and 100 mg/mL, respectively) against L. monocytogenes were observed for SLE and GLE, respectively. GKE had the lowest half-maximal inhibitory concentration ($IC_{50}$) for 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity (5.06 mg/mL). The pH values of meat inoculated with L. monocytogenes and dipped in 1% SLE (LSLE), 1% GLE (LGLE), or 1% GKE (LGKE) were lower than that of the control on day 3 of storage (p<0.05). The initial population of L. monocytogenes in meat was 4.95-5.01 Log CFU/g. However, the population in the LSLE (5.73 Log CFU/g) was lower than that in the control (6.23 Log CFU/g) on day 5 (p<0.05). The volatile basic nitrogen value of the LSLE (19.90 mg/100 g) was lower than that of the control (24.38 mg/100 g) on day 7 (p<0.05). Moreover, treatment with SLE resulted in the maintenance of meat quality and reduced the population of L. monocytogenes on the meat. Thus, SLE may be used as an alternative natural and environmentally friendly sanitizer for reducing L. monocytogenes contamination in the chicken meat industry.

• 농업과학연구
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• 제47권4호
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• pp.1071-1081
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• 2020

Essential oils (EOs) have been shown to be plant-extracted antimicrobial agents. However, there are limited studies investigating the efficacy of EOs against pathogens. Among them, tea tree oil (TTO) is extracted from Melaleuca alternifolia, which is also used as an antifungal agent. In this study, the effect of TTO was investigated on the suppression of melon powdery mildew caused by Podosphaera xanthii and tomato leaf mold disease caused by Passalora fulva. Both powdery mildew and leaf mold diseases were significantly suppressed by a spray of TTO. Eighty percent of powdery mildew and 81% of leaf mold disease of the control value were suppressed by 0.5% TTO liquid, when sprayed 3 times every 7 days on the melon and tomato leaves. Inhibition of mycelial growth was also greatly affected by different concentrations of TTO against four different fungal pathogens. Ninety-eight percent of Pseudocercospora fuligena, 97% of P. fulva, 95% of Botrytis cinerea, and 94% of Phytophthora infestans mycelial growth were inhibited by 0.2% to 1.0% of TTO contained in plate media, respectively. However, phytotoxicity in plants by the TTO treatments was revealed when melon and tomato leaves were sprayed with a 1% and 2% concentration of TTO, respectively. Therefore, our findings show that TTO has high antifungal effects against various plant pathogens that occur during crop cultivation. We also suggest that when applying TTO to plant leaves, it is necessary to establish an accurate treatment concentration for different crops.

• Journal of Veterinary Science
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• 제19권6호
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• pp.808-816
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• 2018

Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at $1/2{\times}MIC/FIC$ concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at $1/4{\times}FIC$ concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p< 0.01) at $1/2{\times}MIC/FIC$ concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the $1/4{\times}FIC$ concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.

• International Journal of Oral Biology
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• 제45권4호
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• pp.143-151
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• 2020

Streptococcus mutans and Streptococcus sobrinus play important roles in dental caries. Coptis chinensis is a natural product with antimicrobial activity against enterobacteria; however, its effects on oral streptococci are still unknown. Therefore, the effects of C. chinensis on the growth and biofilm formation of the representative cariogenic bacteria S. mutans and S. sobrinus were investigated for the possible use of C. chinensis as an anticaries agent. The C. chinensis extract was diluted with sterile distilled water, and 0.1-2.5% of the extract was used in the experiment. The effects of the C. chinensis extract on the growth and glucan formation of S. mutans and S. sobrinus were measured by viable cell counting and spectrophotometry at 650 nm absorbance, respectively. Crystal violet staining was also carried out to confirm the C. chinensis extract's inhibitory effect on biofilm formation. The C. chinensis extract significantly inhibited the growth of S. mutans and S. sobrinus at concentrations of ≥ 0.3% as compared with the control group. The viable cell count of colonies decreased by 1.7-fold and 1.2-fold at 2.5% and 1.25%, respectively, compared with the control group. The biofilm formation of S. mutans and S. sobrinus was inhibited by > 20-fold at C. chinensis extract concentrations of ≥ 1.25% as compared with the control group. In summary, the C. chinensis extract inhibited the growth and biofilm and glucan formation of S. mutans and S. sobrinus. Therefore, C. chinensis might be a potential candidate for controlling dental caries.

• The Plant Pathology Journal
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• 제37권6호
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• pp.533-542
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• 2021

Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture has not been extended yet due to its relatively low solubility in water. N-Methylene phosphonic chitosan (NMPC) is a water-soluble derivative prepared by adding a phosphonic group to chitosan. This study demonstrates that NMPC has a fungicidal effect on the phytopathogenic fungus Fusarium solani f. sp. eumartii (F. eumartii) judged by the inhibition of F. eumartti mycelial growth and spore germination. NMPC affected fungal membrane permeability, reactive oxygen species production, and cell death. Also, this chitosan-derivative exerted antifungal effects against two other phytopathogens, Botrytis cinerea, and Phytophthora infestans. NMPC did not affect tomato cell viability at the same doses applied to these phytopathogens to exert fungicide action. In addition to water solubility, the selective biological cytotoxicity of NMPC adds value in its application as an antimicrobial agent in agriculture.

• 한국미생물·생명공학회지
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• 제49권4호
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• pp.587-593
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• 2021

Infertility is a key issue affecting mood and behavior in men. Microorganisms are one of the primary etiological agents that may be associated with infertility. The objective of the present study was to identify bacterial causative agents from the semen of infertile subjects and determine the effect of bacterial infection on sperm quality, as well as determine the susceptibility of these bacteria to drugs. Forty semen samples from 30 infertile patients and 10 fertile individuals were collected. The pH, volume, motility, and concentration of semen were analyzed. The samples were processed and identified by biochemical testing using API identification kits. The antibiotic susceptibility pattern was determined using the disc diffusion method. Abnormal sperm quality was observed. The mean age of the individual and their sperm morphology, concentration, progressive motility, pH level, and pus cell content were 31.9 years, 2.7%, 10.4 million/ml, 27.3%, 8.3, and 5.7, respectively. Among the tested samples, oligoasthenozoospermia was found to show the highest occurrence, at 27/30 samples, followed by teratozoospermia, at 25/30 samples, and asthenozoospermia, at 22/30 samples. Of the tested infertile patients' sperm, 19, 6, and 5 isolates were identified as Escherichia coli, Klebsiella pneumonia, and Staphylococcus epidermidis, respectively. The results also revealed multi-drug resistance in the bacteria. Compared to that shown by the other tested antibiotics, amikacin showed higher activity against all isolated bacteria. However, the bacteria exhibited maximum resistance against gentamicin, cefotaxime, levofloxacin, and ampicillin. In conclusion, leukocytospermia and bacterial infections are possibly responsible for sperm abnormalities. Multi-drug resistant bacteria were detected. Gentamicin, cefotaxime, levofloxacin and ampicillin were shown the highest resistance, while amikacin was the most effective antimicrobial agent against the isolated bacteria.

• 한국미생물·생명공학회지
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• 제49권4호
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• pp.543-551
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• 2021

Nocardiopsis species produce bioactive compounds, such as antimicrobial and anti-cancer agents and toxins. However, no reports have described their anti-inflammatory and anti-fibrotic effects during nasal polyp (NP) formation. In this study, we investigated whether marine-derived bacterial Nocardiopsis sp. 13G027 exerts anti-inflammatory and anti-fibrotic effects on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and transforming growth factor (TGF)-β1-induced NP-derived fibroblasts (NPDFs). Nitric oxide (NO) and prostaglandin E₂ (PGE₂) levels were analyzed. Extract from Nocardiopsis sp. 13G027 significantly inhibited the upregulation of NO and PGE₂ in LPS-activated RAW 264.7 macrophages. The expression of mitogen-activated protein kinases (MAPKs) and protein kinase B (Akt/PKB) in LPS-induced RAW 264.7 macrophages was evaluated; smooth muscle alpha-actin (α-SMA), collagen type I (Col-1), and fibronectin also phosphorylated small mothers against decapentaplegic (SMAD) 2 and 3 in TGF-β1-stimulated NPDFs. The Nocardiopsis sp. 13G027 extract suppressed the phosphorylation of MAPKs and Akt and the DNA-binding activity of activator protein 1 (AP-1). The expression of pro-fibrotic components such as α-SMA, Col-1, fibronectin, and SMAD2/3 was inhibited in TGF-β1-exposed NPDFs. These findings suggest that Nocardiopsis sp. 13G027 has the potential to treat inflammatory disorders, such as NP formation.

• 한국식품위생안전성학회지
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• 제37권2호
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• pp.55-62
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• 2022

세균성 무름병은 배추와 같은 채소의 주요 질병중의 하나이며, 특히 김치의 주원료인 배추의 저장에 있어서 발생할 경우, 품질 저하로 인한 경제적 손실을 유발한다. 우리는 무름병이 발생한 배추로부터 원인이 되는 세균들을 분리하였고, 해당 세균이 신선한 배추 조직에 인위적으로 접종하였을 경우, 무름병이 발생하는 것을 확인하였다. 해당 원인균 2종을 동정한 결과, Pseudomonas kribbensis와 Pantoea vagans로 확인되었다. 이러한 원인 세균을 제어하기 위하여 차아염소산수 처리와 항균활성 유산균의 배양 상등액을 이용하여 제어하는 테스트를 진행하였다. 본 테스트에 사용한 항균활성 유산균은 리스테리아와 같은 병원성 미생물과 Pseudomonas 속 계열을 저해하는 Lactobacillus plantarum PL203 유산균을 선별하여 사용하였다. 제어 테스트는 정상 배추 조직에 무름병 원인균 2종을 각각 10⁵ cfu/g 이 되도록 접종한 후, 차아염소산수를 농도별로 분무하거나 항균활성 유산균 배양상등액을 0.5 mL 분무한 후, 25℃에서 5일간 배양한 결과, 차아염소산수 120 ppm 이상 첨가한 구간과 항균활성 유산균 배양 상등액을 처리한 구간에서 대조구와 비교하여 배추 무름 원인세균을 완전하게 제어하는 것을 확인하였다.