• Korean Journal of Microbiology
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• v.45 no.2
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• pp.163-169
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• 2009

This study was performed to investigate the type of extended-spectrum $\beta$-lactamases (ESBL) produced by bacteria isolated from the sewage of wastewater treatment plant at Minragdong, Suyong-gu in Busan. The facility is located at sushi restaurants and guides its drain water to the wastewater treatment plant at Yonghodong, Nam-gu in Busan. Samples were collected on January, 2009. A total of 19 strains were selected as potential ESBL positive strains through a double disk synergy test. On the basis of the results from biochemical tests including indole, methyl-red, Voges-Proskauer, Simmon's citrate, decarboxylase-dihydrolase and sugar-fermentation tests, the 19 strains were identified with 16 strains of Escherichia coli and 3 strains of Klebsiella pneumoniae. Out of 19 strains, 4 transconjugants against Escherichia coli J53, which is sodium azide resistant recipient strain, were obtained. The plasmids isolated from transconjugants were used for PCR analysis. The type of each extended-spectrum $\beta$-lactamase (ESBL) produced by the strains was determined on the basis of isoelectric focusing analysis and DNA sequencing. The results indicated that the types of ESBL from Klebsiella pneumoniae were SHV-12 (3 strains), and Escherichia coli was SHV-12/TEM-1 (1 strain), respectively.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.33-43
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• 2013

A bacterium producing a fibrinolytic enzyme was isolated from Cheonggukjang. The bacterium was identified as a strain of Bacillus amyloliquefaciens by 16S rDNA analysis and designated as B. amyloliquefaciens HC188. The optimum culture medium appeared to be one containing 0.5% (w/v) maltose and 0.5% (w/v) soytone. Bacterial growth in the optimal medium at $37^{\circ}C$ reached the stationary phase after 27 h of incubation and the fibrinolytic enzyme showed optimum activity at 24 h. The enzyme was purified by 20-80% ammonium sulfate precipitation, CM Sepharose fast flow ion exchange chromatography, and Sephacryl S-200HR column chromatography. Its specific activity was 38359.3 units/mg protein and the yield was 5.5% of the total activity of the crude extracts. The molecular weight was 24.7 kDa and the amino acids of the N-terminal sequence were AQSVPYGVSQIKAPA. The fibrinolytic enzyme activity had an optimum temperature of $40^{\circ}C$ and an optimum pH of 8.0, and the enzyme was stable in the ranges $20-40^{\circ}C$ and pH 6.0-8.0. Enzyme activity was increased by $Ca^{2+}$ and $Co^{2+}$ but inhibited by $Cu^{2+}$, EDTA, and PMSF. It is suggested that the purified enzyme is a metallo-serine protease.

• Research in Plant Disease
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• v.23 no.1
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• pp.56-59
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• 2017

During growing season of 2011 to 2013, Sclerotinia rot symptoms consistently have been observed on basil in Yesan-gun, Chungcheongnam-do in Korea. The typical symptom formed initially brownish spot on leaf and stem, and then advancing margins, wilting the whole plant and blighting, eventually died. On the surface of diseased lesions was observed cottony, white, dense mat of mycelial growth, and sclerotia ($30-100{\mu}m$ diameter) formed on stem and leaf. Morphological and cultural characteristic on potato dextrose agar, color of colony was white and colorless chocolate, sclerotium of irregular shape of the oval was black and $5-50{\mu}m$ diameter in size. In pathogenicity test, necrosis and wilt of the inoculated stem were observed in all plants and the pathogen was reisolated from stems. On the basis of mycological characteristics, pathogenicity, and internal transcribed spacer rDNA sequence analysis, this fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia rot on basil caused by S. sclerotiorum in Korea.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.237-243
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• 2004

The aim of this study is to investigate the detection rate of putative periodontopathogens, Porphyromonas gingivalis, Tannerella forsythia, and Actiobacillus actinomycetemcomitans, related to cardiovascular diseases(CVD). Plaques were sampled from 15 subjects (4 sites of denture base and/or tooth) with sterilized explorers and were transported in IX PBS. The detection of periodontopathogens was performed by polymerase chain reaction with species-specific primers based on 16S rDNA. The PCR products were cloned into pGEM-T easy vector and its nucleotides were sequenced in order to confirm the specificity. Our data showed that the detection rate of P. gingivalis and T forsythia in denture base of edentulous patients was 25％ and 75％, respectively. And the detection rate of P. gingivalis and T.forsythia in denture base of patient having one more tooth was 91％. The results indicate that plaque of denture base may serve as reservoirs of oral bacteria related to CVD.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.893-902
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• 2011

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive $GA_4$ and $GA_7$. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant's hormones and flavonoids.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.69-69
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• 2018

아로니아(Aronia czarna)는 anthocyanin, polyphenol, flavonoid, cathechine, chlorogenic acid와 같은 생리활성물질이 풍부하게 존재하며 항산화, 항암, 항균, 피부건강개선, 노화방지 등 다양한 생리활성에 대한 효능이 있는 것으로 알려져 있어 건강 및 기능성식품, 화장품 등의 원료 소재로 각광받고 있다. 생물전환(Bioconversion)은 미생물 또는 효소의 생물학적 촉매 반응을 활용하여 기존 소재의 성분을 변환시키는 기술이다, 최근 생물전환을 활용한 천연소재의 생리활성 물질 기능성, 생체이용률, 안전성을 증대시키기 위한 방안으로 많은 연구가 진행되고 있으며 식품, 의약품, 화장품 등 다양한 분야에서 활성화 되고 있다. 본 연구는 젓갈로부터 분리한 균주를 유전학적 특성을 확인하기 위하여 16S rDNA 염기서열을 분석한 뒤 그중 유산균을 발효공정에 활용하였다. 전북 순창에서 수확된 아로니아 분말과 발효공정을 수행하였으며 아로니아 최적 추출조건 선정, 발효공정 전 후 추출물의 기능성 평가를 진행하기 위하여 DPPH radical scavenging activity, Total polyphenol 함량을 확인하여 항산화 효능 및 유효성분 함량을 평가하였다. 또한 대식세포인 Raw 264.7을 사용하여 MTT assay, Nitric oxide (NO) 생성 억제 효능을 확인하여 세포독성 및 항염증 활성을 평가하였다. 실험결과, 젓갈류 발효물로부터 16종의 다양한 균주를 확보하였으며, 그중 L. rhamnosus, L. plantarum, P. pentosaceus 균을 발효 공정에 활용하여 유용 균주를 선정 결과 P. pentosaceus 종 유산균 처리군에서 무처리군 대비 DPPH radical 소거능 및 polyphenol 함량이 증가됨을 확인하였다. 발효공정 후 항산화 활성은 무처리군 대비 약 119%, polyphenol의 함량은 무처리군 대비 약 119%로 증가됨을 확인되었다. 또한 Raw 264.7 세포실험 결과 발효공정 후 독성활성이 감소되는 경향을 확인되었으며, 항염증 활성이 월등히 증가됨을 확인하였다.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.95-102
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• 2012

The purpose of this study is to investigate antioxidant properties in microbial fermentation products of Lonicera japonica Thunb extract. The bacterium Lactobacillus plantarum NHP1 was isolated from conventional fermented foods. Modern pharmacological studies show that Lonicera japonica Thunb and its active principles of wide pharmacological actions. For instance, they show a strong efficacy in antibacterial, anti-inflammatory, antiviral, anti-endotoxin, blood fat reducing, antipyretic, and antioxidant activities. The extract of Lonicera japonica Thunb was obtained by extracting dried Lonicera japonica Thunb using either hot water or 70% ethanol as a solvent. Fermentation was performed in a 2L fermentor containing 1.2 L of extractat conditions of $30^{\circ}C$ and 100 rpm for 48 hr. The amount of cholorogenic acid was $2.65{\mu}g/g$ in hot water extract. The total phenolic content (GAE, gallic acid equivalent) in hot water and 70% ethanol were $56.5{\pm}4.9$ GAE mg/g and $72.7{\pm}5.3$ GAE mg/g, respectively. After fermentation, the phenolic content increased to 30.2% in hot water and 12.9% in ethanol extract. In the same manner, flavonoid content increased to more than 75% regardless of extract solvent. ABTS (2,2-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid) value noticeably increased to 50% after fermentation.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.166-174
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• 2016

In order to find an efficient bacterial strain that can carry out nitrification and denitrification simultaneously, we isolated many heterotrophic nitrifying bacteria from wastewater treatment plant. One of isolates NS13 showed high removal rate of ammonium and was identified as Alcaligenes faecalis by analysis of its 16S rDNA sequence, carbon source utilization and fatty acids composition. This bacterium could remove over 99% of ammonium in a heterotrophic medium containing 140 mg/L of ammonium at pH 6-9, $25-37^{\circ}C$ and 0-4% of salt concentrations within 2 days. It showed even higher ammonium removal at higher initial ammonium concentration in the medium. A. faecalis NS13 could also reduce nitrate and nitrous oxide by nitrate reductase and nitrous oxide reductase, respectively, which was confirmed by detection of nitrate reductase gene, napA, and nitrous oxide reducase gene, nosZ, by PCR. One of metabolic intermediate of denitrification, $N_2O$ was detected from headspace of bacterial culture. Based on analysis of all nitrogen compounds in the bacterial culture, 42.8% of initial nitrogen seemed to be lost as nitrogen gas, and 46.4% of nitrogen was assimilated into bacterial biomass which can be removed as sludge in treatment processes. This bacterium was speculated to perform heterotrophic nitrification and aerobic denitrification simultaneously, and may be utilized for N removal in wastewater treatment processes.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1383-1391
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• 2016

The fungal strain EML-DML3PNa1 isolated from leaf of white dogwood (Cornus alba L.) showed strong nematicidal activity with juvenile mortality of 87.6% at a concentration of 20% fermentation broth filtrate at 3 days after treatment. The active fungal strain was identified as Aspergillus oryzae, which belongs to section Flavi, based on the morphological characteristics and sequence analysis of the ITS rDNA, calmodulin (CaM), and β-tubulin (BenA) genes. The strain reduced the pH value to 5.62 after 7 days of incubation. Organic acid analysis revealed the presence of citric acid (515.0 mg/kg), malic acid (506.6 mg/kg), and fumaric acid (21.7 mg/kg). The three organic acids showed moderate nematicidal activities, but the mixture of citric acid, malic acid, and fumaric acid did not exhibit the full nematicidal activity of the culture filtrate of EML- DML3PNa1. Bioassay-guided fractionation coupled with ¹H- and ¹³C-NMR and EI-MS analyses led to identification of kojic acid as the major nematicidal metabolite. Kojic acid exhibited dose-dependent mortality and inhibited the hatchability of M. incognita, showing EC₅₀ values of 195.2 μg/ml and 238.3 μg/ml, respectively, at 72 h post-exposure. These results suggest that A. oryzae EML-DML3PNa1 and kojic acid have potential as a biological control agent against M. incognita.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.193-199
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• 2018

The fungus, Podosphaera pannosa, was identified in 1991 as the cause of powdery mildew symptoms on peach (Prunus persica var. persica) fruit from Korea based on the morphological characteristics of the conidial state. Recently, however, in Serbia and France, the cause of 'rusty spot' found on peach fruit was identified as P. leucotricha, and the cause of 'powdery mildew' on nectarine (Prunus persica var. nucipersica) fruit was identified as P. pannosa. To confirm the identity of the Korean pathogen, we collected four samples of powdery mildew from Korean peach fruit: three with the 'powdery mildew' symptom and one with the 'rusty spot' symptom. Morphological examination of the four samples confirmed P. pannosa as the pathogen. Internal transcribed spacer sequences of rDNA were analyzed for molecular characterization. A phylogenetic tree showed that the Korean isolates were clustered into a clade containing P. pannosa from Rosa species, with high sequence similarities of more than 99%. Thus, we showed that the powdery mildew and rusty spot symptoms on peach fruits from Korea are associated with P. pannosa.