• The Plant Pathology Journal
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• v.32 no.5
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• pp.431-440
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• 2016

In 2004, bacterial spot-causing xanthomonads (BSX) were reclassified into 4 species-Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. Bacterial spot disease on pepper plant in Korea is known to be caused by both X. axonopodis pv. vesicatoria and X. vesicatoria. Here, we reidentified the pathogen causing bacterial spots on pepper plant based on the new classification. Accordingly, 72 pathogenic isolates were obtained from the lesions on pepper plants at 42 different locations. All isolates were negative for pectolytic activity. Five isolates were positive for amylolytic activity. All of the Korean pepper isolates had a 32 kDa-protein unique to X. euvesicatoria and had the same band pattern of the rpoB gene as that of X. euvesicatoria and X. perforans as indicated by PCR-restriction fragment length polymorphism analysis. A phylogenetic tree of 16S rDNA sequences showed that all of the Korean pepper plant isolates fit into the same group as did all the reference strains of X. euvesicatoria and X. perforans. A phylogenetic tree of the nucleotide sequences of 3 housekeeping genes-gapA, gyrB, and lepA showed that all of the Korean pepper plant isolates fit into the same group as did all of the references strains of X. euvesicatoria. Based on the phenotypic and genotypic characteristics, we identified the pathogen as X. euvesicatoria. Neither X. vesicatoria, the known pathogen of pepper bacterial spot, nor X. perforans, the known pathogen of tomato plant, was isolated. Thus, we suggest that the pathogen causing bacterial spot disease of pepper plants in Korea is X. euvesicatoria.

• The Plant Pathology Journal
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• v.33 no.4
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• pp.382-392
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• 2017

This study reports the findings of a distinct Potato virus Y (PVY) isolate found in Northeast China. One hundred and ten samples (leaves and tubers) were collected from potato plants showing mosaic symptoms around the city of Harbin in Heilongjiang province of China. The collected tubers were planted and let to grow in a greenhouse. New potato plants generated from these tubers showed similar symptoms, except for one plant. Subsequent serological analyses revealed PVY as the causing agent of the disease. A novel PVY isolate (referred to as HLJ-C-44 in this study) was isolated from this sample showing unique mild mosaic and crisped leaf margin symptoms. The complete genome of this isolate was analyzed and determined. The results showed that HLJ-C-44 is a typical PVY isolate. Phylogenetic analysis indicated that this isolate belongs to the N-Wi strain group of PVY recombinants ($PVY^{N-Wi}$) and also shared the highest overall sequence identity (nucleotide and amino acid) with other members of this strain group. However, recombination analysis of isolate HLJ-C-44 revealed a recombination pattern that differed from that of other $PVY^{N-Wi}$ isolates. Moreover, biological assays in four different potato cultivars and in Nicotiana tabacum also revealed a different phenotypic response than that of a typical $PVY^{N-Wi}$ isolate. This data, combined, suggest that HLJ-C-44 is a novel PVY recombinant with distinct biological properties.

• ALGAE
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• v.21 no.2
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• pp.261-266
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• 2006

The innate soluble polysaccharides and phenolic compounds of marine macroalgae are serious contaminants which interfere with experimental procedures such as restriction enzyme digestion, polymerase chain reaction (PCR) and other enzymatic reactions using extracted DNA samples. The viscous polysaccharides are co-precipitated with DNA samples by isopropanol or ethanol precipitation in conventional experiment. To overcome the problem, a method for the isolation of high molecular weight DNA from Porphyra tenera is developed with the application of diatomaceous earth column. The isolated DNAs by this method were about 50-100 kb in size and could be digested well with restriction enzymes. The nuclease activity seemed to be minimal, and high reproducibility in the arbitrary primed PCR for RAPD analyses was a distinctive feature. These results suggest that this method is very efficient in isolating nucleic acid from macroalgae including Porphyra.

• The Journal of the Korean Society for Microbiology
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• v.22 no.2
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• pp.139-145
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• 1987

Adherence to HEp-2 cells has been proposed as a virulence characteristic of enteropathogenic E. coli (EPEC). The role of the HEp-2 adherent E. coli was evaluated in a group of children with endemic diarrhea admitted to Hanyang University Hospital in Seoul, Korea. HEp-2-adherent E. coli was detected in fecal samples of 59 (59%) of 100 cases and ten (22.7%) of 44 concurrent control children (p<0.0005). Adherence was exhibited by 15 serogroups and subgroups, but within these groups more than one adherence pattern was frequently observed. Of 17 strains belonging to traditional infantile EPEC serogroups, 12(70.6%) gave a positive adherence. Of 45 enterotoxin producing strains, 24 (53.3%) gave a positive adherence. HEp-2-adherent strains that did not belong to classic EPEC serogroups and did not produce heat-stable and/or heat-labile enterotoxins(referred as enteroadherent E. coli, EAEC) was found in 29 (29%) of the patients with diarrhea and in six (13.6%) of the well children (p<0.05). From 22 of the 29 cases, no pathogen other than EAEC was isolated. These findings strongly implicate EAEC as the cause of diarrhea in the children. Our study supports the concept that EAEC may be an important cause of endemic diarrhea in Korean children.

• Mass Spectrometry Letters
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• v.5 no.3
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• pp.84-88
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• 2014

Licoricidin isolated from Glycyrrhiza uralensis is known to have anticancer, anti-nephritic, anti-Helicobacter pylori, and antibacterial effects. In this study, a cocktail probe assay and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to investigate the modulating effect of licoricidin on cytochrome P450 (CYP) enzymes in human liver microsomes. When licoricidin was incubated at $0-25{\mu}m$ with CYP probes for 60 min at $37^{\circ}C$, it showed potent inhibitory effects on CYP2B6-catalyzed bupropion hydroxylation and CYP2C9-catalyzed diclofenac 4'-hydroxylation with half maximal inhibitory concentration ($IC_{50}$) values of 3.4 and $4.0{\mu}m$, respectively. The inhibition mode of licoricidin was revealed as competitive, dose-dependent, and non-time-dependent, and following the pattern of Lineweaver-Burk plots. The inhibitory effect of licoricidin has been confirmed in human recombinant cDNA-expressed CYP2B6 and 2C9 with $IC_{50}$ values of 4.5 and $0.73{\mu}m$, respectively. In conclusion, this study has shown the potent inhibitory effect of licoricidin on CYP2B6 and CYP2C9 activity could be important for predicting potential herb-drug interactions with substrates that mainly undergo CYP2B- and CYP2C9-mediated metabolism.

• Journal of Life Science
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• v.7 no.2
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• pp.107-111
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• 1997

To remove dissolved $NH_{4}$$^{+}$ in the aquaculture system, one ammonia oxidizing bacterium, Nitrsomonas sp. PK1, was isolated from samples collected in many aquacultural place and sludges of waste water. The stationary phase of this atrain was reached after 9 days, and the maximum $NO_{2}$ production was shown from 3 days to 9 days. In the selective medium, 0.1% of glucose was the good carbon source for growth. However, the $NO_{2}$productivity was repressed by the addition of glucose to the medium. When $Zn^{++}$ ion was supplemented to the medium, growth and the $NO_{2}$ productivity was increased, 10mM of $ZnCl_{2}$ was the optimal concentration for growth and 1 mM of $ZnCl_{2}$ was the optimal concentration for the production of $NO_{2}$, respectively.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.111-116
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• 1996

Polyphenol oxidase(PPO) isolated from the crude extract of ascidian, Halocynthia roretzi, showed higher affinity for catechol than tyrosine or DL-DOPA. Successful enzyme assay could be performed at $25^{\circ}C$, 10min. by mixing 0.2ml of crude enzyme extract with 2.8ml of 0.13M catechol in 0.1M sodium phosphate buffer(pH 6.4). The specific activity of PPO which had been purified with a combination of ammonium sulfate treatment, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sepharose 6B was 13-fold disc gel electrophoresis. The activity of PPO was stable from pH 5.0 to 8.0 and showed the peak activity at pH 6.4 .The optimum reaction temperature for PPO oxidation on catechol was 35$^{\circ}C$ and those enzyme were heat stable up to 4$0^{\circ}C$. Molecular weigth of the enzyme was estimated about 170kDa. One molecule was found to be composed of gour subunits. Two of them had molecular weigh of 55kDa and the others 30kDa. The {TEX}$K_{m}${/TEX} values, {TEX}$V_{max}${/TEX} and catalytic efficiency({TEX}$V_{max}${/TEX}/{TEX}$K_{m}${/TEX}) for catechol were 0.12mM, 2.5mM/liter/min. and {TEX}$0.18min^{-1}${/TEX} respectively. The substrate affinity and electrophorectic pattern suggested that the enzyme of ascidian was considered to be not tyosine but catechol oxidase.

• Journal of Korean Society of Forest Science
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• v.79 no.4
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• pp.431-434
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• 1990

The growth pattern of bud-shoot-needle of isolated 15-year-old trees, and seansonal changes in litter-falls and fine root dry weights in the unthinned 28-year-old plantation were investigated to understand the growth phenology of Pinus koraiensis. Shoot growth was continued by 7th June when buds appeared, while current needle growth was by 19th July when the bud growth started. Most of the litter-falls occurred in October but many of them were fallen in July and August due to storms, Fine roots were produced mostly in autumn(1,004 kg/ha), and were dead during winter (583 kg/ha) and spring(1,331 kg/ha).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.187-194
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• 2008

Because the types and severities of most engine faults are various and complex, it is not easy that the conventional model based fault detection approach like the GPA(Gas Path Analysis) method can monitor all engine fault conditions. Therefore this study proposed newly a diagnostic algorithm for isolating and diagnosing effectively the faulted components of the smart UAV propulsion system, which has been developed by KARI(Korea Aerospace Research Institute), using the fuzzy logic and the neural network algorithms. A precise performance model should be needed to perform the model-based diagnostics. The based engine performance model was developed using SIMULINK. For the work and mass flow matching between components of the steady-state simulation, the state-flow library was applied. The proposed steady-state performance model can simulate off-design point performance at various flight conditions and part loads, and in order to evaluate the steady-state performance model their simulation results were compared with manufacturer's performance deck data. According to comparison results, it was confirm that the steady-state model well agreed with the deck data within 3% in all flight envelop. The diagnosis procedure of the proposed diagnostic system has the following steps. Firstly after obtaining database of fault patterns through performance simulation, then secondly the diagnostic system was trained by the FFBP networks. Thirdly after analyzing the trend of the measuring parameters due to fault patterns, then fourthly faulted components were isolated using the fuzzy logic. Finally magnitudes of the detected faults were obtained by the trained neural networks. Because the detected faults have almost same as degradation values of the implanted fault pattern, it was confirmed that the proposed diagnostic system can detect well the engine faults.

• Journal of Chest Surgery
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• v.54 no.5
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• pp.361-368
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• 2021

Background: In general, a 2-cm surgical margin is recommended for limited resection to obtain equivalent oncologic outcomes to lobectomy for lung cancer. This study aimed to examine the patterns of recurrence and prognostic factors for recurrence in patients with a close parenchymal resection margin. Methods: From January 2009 to April 2017, 156 patients with stage I lung cancer who underwent segmentectomy with a close resection margin (<2 cm) were enrolled. Recurrence-free survival and overall survival were assessed. In addition, predisposing factors for recurrence were evaluated. Results: The mean tumor size was 1.7±0.8 cm and the parenchymal resection margin was 1.1±0.6 cm. Recurrence developed in 17 (10.7%) of the 156 patients, and the 5-year recurrence-free survival rate was 88.9%. Distant metastasis (7.7%) was the predominant recurrence pattern. The isolated local recurrence rate was 1.9%. Multivariate Cox regression analysis revealed that age, tumor size, mediastinal lymph node dissection, postoperative complications, and histologic type were significant predisposing factors for recurrence. However, parenchymal margin distance did not significantly affect the long-term prognosis. Conclusion: Segmentectomy with a close resection margin for early-stage lung cancer in selected patients resulted in acceptable recurrence and survival. However, patients with tumors larger than 2 cm, squamous cell carcinoma histology, and insufficient mediastinal evaluation should be carefully followed up for recurrence.