• Korean Journal of Microbiology
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• v.50 no.2
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• pp.128-136
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• 2014

Acyl homoserine lactone (AHL) lactonase has been proved to be the AHL-degrading enzyme with the highest substrate specificity for AHL molecules and has shown a considerable potential as low-cost and efficient quorum quenching (QQ) technique. However, few studies focused on its inhibitory effect on biofilm formation which is also a quorum sensing (QS)-regulated phenomenon. In this study, QQ activity of six isolates from biofouled reverse osmosis membranes was studied using Chromobacterium violaceum CV026 and Agrobacterium tumefaciens NTL4 as biosensors under various conditions. All of the isolates belonged to the genus Bacillus and showed QQ activity regardless of the acyl chain length or substitution of AHL molecule. The isolates were capable of significantly inhibiting biofilm formation (46.7-58.3%) by Pseudomonas aeruginosa PAO1 and produced heat-sensitive extracellular QQ substances. The LC-MS analysis of the QQ activity of a selected isolate, RO1S-5, revealed the degradation of N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 AHL) and the production of corresponding acyl homoserine (3-oxo-C12-HS), which indicated the activity of AHL lactonase. The broad AHL substrate range and high substrate specificity suggested that the isolate would be useful for the control of biofilm-related pathogenesis and biofouling in industrial processes.

• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.9-19
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• 2011

The Bacillus subtilis pyrimidine biosynthetic (pyr) operon encodes all of the enzymes for the de novo biosynthesis of Uridine monophosphate (UMP) and additional cistrones encoding a uracil permease and the regulatory protein PyrR. The PyrR is a bifunctional protein with pyr mRNA-binding regulatory funtion and uracil phosphoribosyltransferase activity. To study the global regulation by the pyrR deletion, the proteome comparison between Bacillus subtilis DB104 and Bacillus subtilis DB104 ${\Delta}$pyrR in the minimal medium without pyrimidines was employed. Proteome analysis of the cytosolic proteins from both strains by 2D-gel electrophoresis showed the variations in levels of protein expression. On the silver stained 2D-gel with an isoelectric point (pI) between 4 and 10, about 1,300 spots were detected and 172 spots showed quantitative variations in which 42 high quantitatively variant proteins were identified. The results showed that production of the pyrimidine biosynthetic enzymes (PyrAA, PyrAB, PyrB, PyrC, PyrD, and PyrF) were significantly increased in B. subtilis DB104 ${\Delta}$pyrR. Besides, proteins associated carbohydrate metabolism, elongation protein synthesis, metabolism of cofactors and vitamins, motility, tRNA synthetase, catalase, ATP-binding protein, and cell division protein FtsZ were overproduced in the PyrR-deficient mutant. Based on analytic results, the PyrR might be involved a number of other metabolisms or various phenomena in the bacterial cell besides the pyrimidine biosynthesis.

• Journal of Life Science
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• v.22 no.4
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• pp.437-446
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• 2012

A metagenomic library of cow rumen in the pCC1FOS phage vector was screened in $E.$ $coli$ EPI300 for cellulase activity on carboxymethyl cellulose agar plates. One clone was partially digested with $Sau$3AI, ligated into the $Bam$HI site of the pBluescript II SK+ vector, and transformed into $E.$ $coli$ $DH5{\alpha}$. We obtained a 1.5 kb insert DNA, designated $cel$5C, which hydrolyzes carboxymethyl cellulose. The cel5C gene has an open reading frame (ORF) of 1,125 bp encoding 374 amino acids. It belongs to the glycosyl hydrolase family 5 with the conserved domain LIMEGFNEIN. The molecular mass of the Cel5C protein induced from $E.$ $coli$ $DH5{\alpha}$, as analyzed by CMC SDS-PAGE, appeared to be approximately 42 kDa. The enzyme showed optimum cellulase activity at pH 4.0, and $50^{\circ}C$. We examined whether the $cel$5C gene comes from the 49 identified cow rumen bacteria using PCR. No PCR bands were identified, suggesting that the $cel$5C gene came from the unidentified cow rumen bacteria.

• Journal of Life Science
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• v.22 no.2
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• pp.259-265
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• 2012

A bacterial strain, CK214, exhibiting high motility on an LB agar (1.5%, w/v) surface was isolated from the environment. The formation of unusual agar shrinking around colonies on agar plates was observed. The strain grew on minimal media containing pure agar as a sole carbon source. The cell-free culture supernatant of CK214 generated a reduced form of sugar in the in vitro reaction with the use of pure agar as a substrate, suggesting the secretion of an agar-degrading enzyme. The CK214 strain showed swarming motility on the solid media containing a wide range of concentrations of agar (0.5, 1.0, 1.5, 2.0% w/v). Various tests, including Gram staining, API analysis, and phylogenetic analysis based on 16S rDNA sequences identified that the CK214 strain was a G(+) rod-shaped bacterium grouped in genus Paenibacillus. Electron microscopic analysis demonstrated that the P. CK214 strain is peritrichously flagellated. Through transposon random mutagenesis, several agar-degrading activity defective mutants (ADMs) were generated. These mutants will be used in the future experimentation for the study of the correlation between agar-degrading activity and motility.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2043-2049
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• 2015

Background: Serum Golgi protein 73 (GP73) as a novel and potential marker for diagnosing hepatocellular carcinoma (HCC) have been found to be elevated in HCC patients and associated with clinical variables representing tumor growth and invasiveness. The aim of this study was to prepare a pair of monoclonal antibodys (mAbs) against GP73 and develop a newly designed double-antibody sandwich enzyme-linked immunosorbent assay (s-ELISA), which would be used in the detection of serum GP73 (sGP73) as well as in the diagnosis of HCC. Materials and Methods: Produced by prokaryotic expression, the purified recombinant GP73 (rGP73), produced by prokaryotic expression, was used to immunize the Balb/c mice. Two hybridoma cell lines against GP73 were obtained by fusing mouse Sp2/0 myeloma cells with spleen cells from the immunized mice. The titers of anti-GP73 mAb reached 1:243,000. Western blotting analysis and Immunohistochemistry staining revealed that anti-GP73 mAb could recognize GP73 protein. The double-antibody s-ELISA was successfully established and validated by 119 HCC and 103 normal serum samples. Results: showed that the detection limit of this method could reach 1.56 ng/ml, and sGP73 levels in HCC group (mean=190.6 ng/ml) were much higher than those of in healthy controls (mean=70.92 ng/ml). Conclusions: Results of our study not only showed that sGP73 levels of HCC patients were significantly higher than those of healthy controls, but also indicated that the laboratory homemade anti-GP73 mAbs could be the optimal tool used in evaluating sGP73 levels, which would provide a solid foundation for subsequent clinical applications.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.195-203
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• 2015

Two bacterial strains, Bacillus licheniformis YB-1413 and YB-1414, producing extracellular α-galactosidase, were obtained from homemade Doenjang. On the basis of their biochemical properties, 16S rRNA sequences and random amplified polymorphic DNA patterns by polymerase chain reaction, they were found to be somewhat different from one another. α-Galactosidase productivities of the two isolates were increased by wheat bran, but drastically decreased by melibiose, raffinose and sucrose which were used as carbon sources. The enzyme productivities were increased by yeast extract as a nitrogen source with maximum levels of 1.87 U/ml for YB-1413 and 1.69 U/ml for YB-1414, respectively. The enzymes of both isolates exhibited maximum activity for hydrolysis of para-nitrophenyl-α-D-galactopyranoside (pNP-αGal) under reaction conditions of pH 6.0 and 45℃. Their hydrolyzing activities for pNP-αGal were drastically decreased by the addition of low concentrations of ribose and galactose. They were capable of hydrolyzing completely α-1,6 linked galactosyl residue in melibiose, raffinose and stachyose, which are known to be anti-nutritional factors in products of soybean and legume. In relation to the latter, the isolates YB-1413 and YB-1414 have potential applicability in improving soybean-fermented foods and the nutritional value of soybean feed.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.442-446
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• 1991

Three peroxidase fractions (peak I, II, III) were isolated from Fuji apples using CM-cellulose chromatography. The homogeneity of the isolated peroxidase isozymes was established by isoelectric focusing and electrophoresis. Isoelectric points of the isozymes were 3.80, 3.82, and 3.85, respectively. The optimum pH of peroxidase isozymes were pH 5.0(peak I) or 5.5(peak II, III), and optimum temperature was $40^{\circ}C$ when assayed by using guaiacol and $H_{2}O_{2}$ as substrates. Inactivation rate of three peroxidase isozymes were different at temperature of $70^{\circ}C$ and at pH of 5.5. The isozyme of peak II was found to be more heat stable than those of peak I and III. D values at $70^{\circ}C$ of peroxidase isozymes (peak I, II, III) were estimated to be 660 sec, 1,320 sec, and 600 sec, respectively. The thermal stability of Fuji apple peroxidase was not influenced in the presence of 0.032 M sucrose or lactose. However, the thermal stability of the enzyme was decreased by fructose and glucose.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.131-139
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• 2007

From the course of screening of useful enzyme producing microorganism from insect guts, we isolated 9 lipase producing strains and their lipase producing activities were tested. 16S rDNA sequence analysis showed that they were Gram negative bacteria grouped on Serratia sp., Pseudomonas sp., and Burkholderia sp.. Among them, an excellent lipase producing strain, Burkholderia sp. HY-10 identified by 16S rDNA analysis and biochemical methods, was further studied its lipase producing characteristics. It was isolated from a longcorm beetle, Prionus insularis and showed cell density dependent lipase producing activity in the culture media that contained olive oil as a carbon source. Maximum lipase production was achieved in the M9 media containing 0.5% yeast extract and 0.5% olive oil when cultured at $30^{\circ}C$ for 36-42 hrs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.690-695
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• 2016

This study was performed to evaluate the effect of alkaline treatment on Styela clava tunic (SCT). Considerable damage to the surface of alkali-treated SCT was observed by scanning electron microscopy (SEM) in a concentration-dependent manner upon alkaline treatment. The amount of crystalline region in SCT gradually increased with increasing NaOH concentration, which was analyzed by X-ray diffraction and thermogravimetric analysis. The initial enzymatic reaction of Celluclast toward SCT was elevated by treatment with NaOH up to 1.0 N concentration due to disruption of the SCT surface by promoting binding of enzymes with SCT. However, in the late stage of the enzyme reaction, hydrolysis rate decreased with elevation of NaOH concentration, thereby increasing the amount of non-reacted residuals. This result was due to the increase in the crystalline regions in SCT.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.179-184
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• 2006

This study was carried out to evaluate major agronomical characterization and phenol compound contents, Xanthine oxidase inhibitory activity (XO), Catalase activity, Superoxide dismutase activity (SOD) and 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical sacvenging activity were analyzed in colored waxy corns. The mean of stem height and ear length were 248.8 cm and 18.6 cm, respectively. The pericarp thickness in CNU108 $(30.3{\mu}m)$ was thinner than other hybrids. The period of tasseling days in CNU69 and CNU202 were very shorter than other hybrids (59 days). 100-kernel weight of CNU50 was 35.6 g and heavier than the others. The antioxidant activities such as xanthin oxidase (XO), catalase and superoxide dismutase (SOD) were higher in CNU70 and CNUI 38. Especially highest EDA (electron donating ability) in DPPH radical scavenging effect was 94.8% and 94.6% in CNU160 and CNU193, respectively. In the results, the antioxidant enzyme activity and antioxidant acticity were higher in CNU109 and CNU 34 hybrids. The hybrids, CNU34, CNU70, CNU108, CNU 138 and CNU193 may be considered higher functional color waxy corn.