• The Korean Journal of Physiology and Pharmacology
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• v.8 no.5
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• pp.289-293
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• 2004

To investigate whether VacA (vacuolating toxin) produced by Helicobacter pylori Korean stain 99 induces intestinal secretion, purified VacA was added to T84 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of low pH-pretreated VacA increased short circuit current (Isc). The effect was time- and dose-dependent and saturable. The time-to-peak Isc was concentration-dependent. Chloride channel inhibitors, niflumic acid or 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), inhibited VacA-stimulated Isc. Carbachol (CCh)-induced increase of Isc was prolonged by the addition of VacA to the mucosal side only. The effect was unaltered by the addition of niflumic acid. VacA did not show cytopathic effects. These studies indicate that VacA is a nonlethal toxin that acts in a polar manner on T84 monolayers to potentiate $Cl^-$ secretion and the response to CCh secretion without decrease in monolayer resistance. VacA may contribute to diarrhea diseases in human intestinal epithelial cells.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.94.2-95
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• 2003

E. intermedium 60-2G possessing a strong ability to solubilize insoluble phosphate, has plant growth-promoting activity, induced systemic resistance activity against scab pathogen in cucumber, and antifungal activity against various phytopathogenic fungi. The phosphate solubilizing activity of 60-2G may be mainly accomplished by production of gluconic acid through a direct extracellular oxidation of glucose by glucose dehydrogenase that required a PQQ cofactor for its activation. A pqq gene cluster conferred Phosphate-solubilizing activity in E. coli DH5${\alpha}$ was cloned and sequenced. The 6,783 bP pqq sequence had six open reading frames (from A to F) and showed 50-95％ homology to pqq genes from other bacteria. The E. coli strain expressing the pqq genes solubilized phosphate from hydroxyapatite after a pH drop to 4.0, which paralleled in time the secretion of gluconic acid. To study the role of PQQ in biocontrol traits of E. intermedium, PQQ mutants of 60-2G were constructed by marker exchangee mutagenesis. The PQQ mutants of E. intermedium were lost activities of solubilizing phosphate, growth inhibition of phytopathogenic fungi, and plant growth promotion. These findings suggest that PQQ plays an important role, possibly activation of certain enzymes, in several beneficial bacterial traits of E. intermedium by as yet an unknown mechanism.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.109.1-109
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• 2003

From the PMMV (pepper mild mottle virus)-inducible ESTs differentially expressed in Capsicum chinense PI257284, we isolated a full-length cDNA (CcPHZF： Capsicum chinense phenazine), encoding a phenazine biosynthesis protein which catalyzes the hydroxylation of phenozine-1-carboxylic acid to 2-hydroxyphenazine-1-carboxylic acid. Phenazine compound has been known to exhibit broad-spectrum of antibiotic activity against various species of bacteria and fungus. The entire region of CcPHZF is 879 bp in length and the open reading frame predicted a polypeptide of 292 amino acids. The homolog of CcPHZF is not Present in database except clones of AC004044 and NM100203 from Arabidopsis with 58 and 59％, respectively. Genomic Southern analysis indicated that the pepper genome contains a single copy of CcPHZF. The CcPHZF was strongly induced in the pepper leaves 3 days after PMMV treatment, when HR occurs on the leaf surface. Characterization of CcPHZF is underway to investigate if the CcPHZF is related to disease resistance against pathogens.

• Journal of the Korean Electrochemical Society
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• v.7 no.3
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• pp.138-142
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• 2004

The polyaniline films of emeraldine base (EB) and leucoemeraldine base (LEB) form doped with cam-phorsulfonic acid (CSA) were prepared by casting the mixed solution of chloroform and m-cresol on ITO (indium tin oxide) electrode. By analyzing UV-vis spectra of the mixed solutions, the effects of the secondary doping by m-cresol were obtained. And the conductivity of polyaniline film was increased with increasing m-cresol content. As the results of analyzing cyclic voltammograms, it was known that the redox peak currents of polyaniline electrode prepared from LEB were larger and more reversible than those of polyaniline eleclrodes prepared from EB. The charge transfer resistances $(R_{ct})$ of polyaniline electrodes were reduced with increasing m-cresol content, showing smaller Rct for LEB/CSA than EB/CSA.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.167-172
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• 2007

A tomato zinc-finger protein gene, LeZFP1, encoding the Cys2/His2-type zinc-finger transcription factor was searched from cDNA microarray analysis of gene expression following induction of the overexpressed tomato transgenic plants showing resistance for pathogen and abiotic stresses. The full-length cDNA of LeZFP1 encoded a protein of 261 amino acid residues. Analysis of the deduced amino acid sequence of LeZFP1 revealed that it shares high sequence identity with pepper CAZFP1 (81% identity). We found that single copy of LeZFP1 gene is present in the tomato genome through southern blot analysis. The LeZFP1 transcripts were constitutively expressed in the tomato mature and young leaves, but were detectable weakly in the flower, stem and root. The LeZFP1 transcripts were significantly reduced in treated leaf tissues with NaCl and mannitol. The LeZFP1 gene was induced by oxidative stress especially. Our results indicated that LeZFP1 may play a role function involved in oxidative stress signaling pathways.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.23-27
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• 1999

The development and industrial application of intestinal anaerbic bacteria is highly important in the munufacture of foodstuffs and medical products. We have conducted studies, screening anaerobic intestinal bacteria for acid and bile tolerance and for pathogens suppression in the intestine of swine. One such study was taxonomic in nature and dealt with the isolate's biochemical responses. The results indicated that the BSA-131 strian ioslated. which suppressed various pathogens (13 typical strains), were identified as Lactobacillus reuterii. The strain, which named L. reuterii BSA-131, was able to tolerate acid condition down to pH2 and could also tolerate bile at 5%. The strain exhibited resistance to a range of antibiotics including, cephalexin, erythromycin, flumequine, furazolidine, gentamycin, penicillin G, norfloxacin, spectinomycin, tetracycline, tiamuline, neomycin, chloramphenicol, kanamycin etc.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.95-104
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• 1997

The objectives of this study are to investigate the effect of media on the removal efficiency of nitrate-nitrogen and the biofilm thickness in the fluidized bed biofilm reactor(FBBR) used for the high rate denitrification of nitric acid wastewater. Granular activated carbon(GAC) of 1.274 mm diameter and sand of 0.455 mm diameter were used as the media in the FBBR of 0.05 m diameter and 1.5 m height. As the nitrate-nitrogen concentration of the influent was increased stepwise from 600 to 4800 mg/l, the nitrate- and nitrite-nitrogen concentration of the effluent, biofilm thickness and biofilm dry density were measured to study the effects of media on the denitrification efficiency. The biofilm thickness increased with the substrate loading rate, and the biofilm dry density decreased with the increase of the biofilm thickness. At the influent nitrate-nitrogen concentration of 2400 mg/l, the removal efficiency in the FBBR with GAC was 88%, while that in the FBBR with sand was 99.6%. The biofilm in the FBBR with GAC was so thick, 754.9 $\mu$m, as to increase the mass transfer resistance, compared to that, 143.7 $\mu$m, in the FBBR with sand. The maximum specific denitrification rate in the FBBR with GAC was 15.0 kg-N/m$^3\cdot$ day, while that in the FBBR with sand was 18.0 kg-N/m$^3\cdot$ day. The biomass concentration in the FBBR with sand exhibited the high value 37 kg/m$^3$.

• The Plant Pathology Journal
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• v.27 no.3
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• pp.272-279
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• 2011

Root colonization of Arabidopsis thaliana with Pseudomonas chlororaphis O6 induces systemic tolerance against diverse pathogens, as well as drought and salt stresses. In this study, we demonstrated that 11 genes in the leaves were up-regulated, and 5 genes were down-regulated as the result of three- to five-days root colonization by P. chlororaphis O6. The identified priming genes were involved in cell signaling, transcription, protein synthesis, and degradation. In addition, expression of selected priming genes were induced in P. chlororaphis O6-colonized plants subjected to water withholding. Genes encoding defense proteins in signaling pathways regulated by jasmonic acid and ethylene, such as VSP1 and PDF1.2, were additional genes with enhanced expression in the P. chlororaphis O6-colonized plants. This study indicated that the expression of priming genes, as well as genes involved in jasmonic acid- and ethylene-regulated genes may play an important role in the systemic induction of both abiotic and biotic stress due to root colonization by P. chlororaphis O6.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.101-106
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• 2005

Photocurable modified 6 functional polyacrylate(PA-1) were prepared from dipentaerythritol derivatives (DPET) and acrylic acid, and 12 functional polymethacrylate(PA-2) were prepared from dipentaerythritol derivatives (DPET), trimellitic anhydride, and glycidyl methacrylate. And physical properties of photocurable modified poly(meth)acrylate were increased with increasing functionality of (meth)acrylate. Thermal stability of UV cured film obtained by using TGA was shifted to higher temperature as the increasing of functionality. Hardness, abrasion resistance and tensile strength of UV cured film were increased with increasing functionality of (meth)acrylate. Values of yellow index were increased with increasing functionality of (meth)acrylate.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.161-168
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• 2010

In this study, the metabolic activities of five strains of Pediococcus spp., in terms of the quantities they produced of lactic acid, hydrogen peroxide, exopolysaccharides, and proteolytic activity, were determined. Lactic acid levels produced by these strains were found to be in the range of 2.5-5.6 mg/ml. All strains produced hydrogen peroxide. The P. pentosaceus Z13P strain produced the maximum amount (0.25 mg/ml) of proteolytic activity. Exopolysaccharide (EPS) production by the Pediococcus strains during growth in MRS (de Man, Rogosa, and Sharpe) medium was in the range 25-64 mg/l. The susceptibility of 10 different antibiotics against these strains was also tested. All strains were found to be resistant to amoxicillin, gentamicin, and vancomycin. Antimicrobial effects of the Pediococcus spp. on pathogens were also determined by an agar diffusion method. All of the strains were able to inhibit L. monocytogenes. The tolerance of the strains to low pH, their resistance to bile salts of strains, and their abilities to autoaggregate and coaggregate with L. monocytogenes were also evaluated.