• Journal of Microbiology and Biotechnology
• /
• v.29 no.12
• /
• pp.1982-1992
• /
• 2019

The alkaliphilic, calcium carbonate precipitating Bacillus sp. strain AK13 can be utilized in concrete for self-repairing. A statistical experimental design was used to develop an economical medium for its mass cultivation and sporulation. Two types of screening experiment were first conducted to identify substrates that promote the growth of the AK13 strain: the first followed a one-factor-at-a-time factorial design and the second a two-level full factorial design. Based on these screening experiments, barley malt powder and mixed grain powder were identified as the substrates that most effectively promoted the growth of the AK13 strain from a range of 21 agricultural products and by-products. A quadratic statistical model was then constructed using a central composite design and the concentration of the two substrates was optimized. The estimated growth and sporulation of Bacillus sp. strain AK13 in the proposed medium were 3.08 ± 0.38 × 10⁸ and 1.25 ± 0.12 × 10⁸ CFU/ml, respectively, which meant that the proposed low-cost medium was approximately 45 times more effective than the commercial medium in terms of the number of cultivatable bacteria per unit price. The spores were then powdered via a spray-drying process to produce a spore powder with a spore count of 2.0 ± 0.7 × 10⁹ CFU/g. The AK13 spore powder was mixed with cement paste, yeast extract, calcium lactate, and water. The yeast extract and calcium lactate generated the highest CFU/ml for AK13 at a 0.4:0.4 ratio compared to 0.4:0.25 (the original ratio of the B4 medium) and 0.4:0.8. Twenty-eight days after the spores were mixed into the mortar, the number of vegetative cells and spores of the AK13 strain had reached 10⁶ CFU/g within the mortar. Cracks in the mortar under 0.29 mm were healed in 14 days. Calcium carbonate precipitation was observed on the crack surface. The mortar containing the spore powder was thus concluded to be effective in terms of healing micro-cracks.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.4
• /
• pp.730-738
• /
• 2016

est19 is a gene from Bacillus sp. K91 that encodes a new esterase. A comparison of the amino acid sequence showed that Est19 has typical Ser-Gly-Asn-His (SGNH) family motifs and could be grouped into the SGNH hydrolase family. The Est19 protein was functionally cloned, and expressed and purified from Escherichia coli BL21(DE3). The enzyme activity was optimal at 60℃ and pH 9.0, and displayed esterase activity towards esters with short-chain acyl esters (C₂-C₆). A structural model of Est19 was constructed using phospholipase A1 from Streptomyces albidoflavus NA297 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of the typical catalytic triad Ser49-Asp227-His230, which were further investigated by site-directed mutagenesis. To the best of our knowledge, Est19 is a new member of the SGNH hydrolase family identified from thermophiles, which may be applicable in the industrial production of semisynthetic β-lactam antibiotics after modification.

• Journal of Korean Society of Transportation
• /
• v.21 no.1
• /
• pp.77-90
• /
• 2003

This paper explores the way and the extent to which drivers' route choice was influenced by uncertain information. In particular, this paper investigates the effect of qualitative information on route choice when drivers face a choice with different degrees of uncertain information. The SP survey was conducted and route choice legit models were estimated. We also applied Prospect Theory to the analysis of drivers' decision making under uncertain information. The main findings are firstly, drivers tend to prefer a route with information than(to) one without information. This indicated that providing charge information encouraged drivers to choose the routes for which information is provided in preference to those for which it is not provided. Secondly, drivers also prefer a route with a certain and precise information over one with uncertain and imprecise information. Thirdly, when the information is given as a range, the size of the range of the information influenced route choice slightly and as the range of the charge increases, the route becomes slightly less unattractive. Fourthly, when the information is given as a range, drivers' route choices are influenced more by the median value of the ranges than by the size of the overall ranges of the information. Application of Prospect Theory to the results explains the way drivers may be interpreting the choice situation and how they make a route choice in response to uncertain information. The results of this paper implicate that drivers' decision making under uncertainty seem to be very complicated and flexible, depending on the way drivers interpret the choice situation. Therefore, it is recommended to apply wider related theories to the analysis of the drivers' behaviour.

• Applied Biological Chemistry
• /
• v.46 no.3
• /
• pp.176-182
• /
• 2003

An alkaline fibrinolytic protease-producing bacteria was isolated front Korean traditional soy sauce and identified as Bacillus subtilis K7 from the results of analyses of its morphological and physiological properties, $API^{\circledR}$, and Biolog system. The enzyme was purified by 75% ammonium sulfate fractionation, QAE-Sephadex anion and SP-Sephadex cation exchange column chromatography and Sephadex G-100 gel filtration. The specific activity of the purified enByme was 233.9 unit/mg protein and the yield of enzyme was 3.8%. The homogeneity of the purified enzyme was confirmed by polyacrylamide gel electrophoresis. Molecular mass of the enzyme was estimated about 21,500 Da by SDS-polyacrylamide get electrophoresis and gel chromatography. The optimum temperature and pH for the enzyme activity were $40^{\circ}C$ and 9.0, respectively. The enzyme was stable in a pH range of 5.0 to 12.0, and 60% of its activity was lost on heat treatment at $50^{\circ}C$ for 20 min. The activity of the purified enzyme was inhibited by the presence of $Fe^{2+},\;Ag^{2+},\;Cu6{2+}$, iodoacetate, ethylene diamine tetraacetic acid (EDTA), and trans-1,2-diaminocycloheane-N,N,N',N'-tetraacetic acid (CDTA). The results indicates that the enzyme requires a metal ion for its enzymatic activity.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.1
• /
• pp.145-153
• /
• 2013

In this study, shear punch-creep (SP-Creep) at Sn-4Ag/Cu pad the joint was tested by using environment-friendly Pb-free solder alloy Sn-4Ag of electronic components. Pb eutectic alloy (Sn-37Pb) joints limited to environmental issues with reflow time (10sec, 30sec, 100sec, 300sec) according to two types of solder alloy joints are compared and evaluated by creep strain rate, rupture time and IMC (Intermetallic Compound) behavior. As the results, reflow time increases with increasing thickness of IMC can be seen at overall 100sec later in case of two solder joints on the IMC thickness of Sn-4Ag solder joints thicker than Sn-37Pb solder joints. In addition, when considering creep evaluation factors, lead-free solder alloy Sn-4Ag has excellent creep resistance more than Pb eutectic alloy. For this reason, the two solder joints, such as in the IMC (Cu6Sn5) was formed. However, the creep resistance of Sn-4Ag solder joints was largely increased in the precipitation strengthening effect of dispersed Ag3Sn with interface more than Sn-37Pb solder joints.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.5
• /
• pp.519-523
• /
• 2002

Soluble polysaccharide (SP) from green layer, Enteromorpba prolifera was extracted 3 times with distilled water at 100$^{\circ}C$ for 2 hrs and fractionated with cetylpyridinium chloride (CPC) and ion exchange chromatography (DEAE Separose CL-6B). The SP amounted to $23.7\%$ of the dry seaweed weight and contained $68.8\%$ carbohydrate. It was mainly constituted of rhamnose, glucose, xylose, sulfate and uronic acid and was fractionated with CPC into three (CPC-S, CPC-PS, CPC-PP) tractions. The major acid fraction CPC-PS accounted for $10.2\%$ of the dry algal weight. CPC-PS was further fractionated on DEAE Sepharose CL-6B into Fr-1 ($8.0\%$), Fr-2 ($35.8\%$), Fr-3 ($23.7\%$) fractions. The Fr-3 fraction contained $2.2\%$ protein, $21.4\%$ sulfate, $15.3\%$ uronic acid, and $72.4\%$ polysacchnrides composed of rhamnose, xylose and glucose. The Fr-2 fraction, which was richer in uronic acid ($17.5\%$) and poorer in sulfate ($19.0\%$) and total sugar ($68.8\%$) than the Fr-3, had a sugar composition close to that of Fr-3. The average molecular weights of Fr-2 and Fr-3 were 510,000 and 830,000 daltons, respectively. Fr-3 turned out to be homogeneous by cellulose acetate electrophoresis.

• Korean Journal of Poultry Science
• /
• v.30 no.2
• /
• pp.113-118
• /
• 2003

In this study, broilers were raised up to 6 weeks of age in a single room to determine if different levels of dietary protein or addition of aluminum sulfate[alum, $Al_2$(SO$_4$)$_3$ㆍ14$H_2O$] to the litter affected growth performance, production of ammonia(NH$_3$) and soluble phosphorus(SP) content of the litter.The experimental treatments consisted of six treatments in a 2x3 factorial arrangements: T$_1$＝23% protein ＋ 0.2% alum to litter; T$_2$＝21% protein ＋ 0.2% alum to litter; T$_3$＝19% protein ＋ 0.2% alum to litter; T$_4$＝23% protein ＋ no alum; T$_{5}$＝21% protein ＋ no alum; T$_{6}$＝19% protein ＋ no alum. For broiler performance, there was no effect of alum addition to the litter, but the dietary protein levels significantly affected feed intake from days 22 to 42(P<0.05) and day 0 to 42(P< 0.05), weight gain during all periods(P<0.05 or 0.01), and feed:gain from day 0 to 21(P<0.05) and day 0 to 42(P<0.05). Alum addition to the litter did not affect body weight at 21 and 42 days, but dietary protein levels has a significant effect on it at both 21(P<0.0l) and 42 days(P<0.05). Alum addition only affected ammonia production at weeks 3(P

• Journal of Life Science
• /
• v.15 no.3 s.70
• /
• pp.323-331
• /
• 2005

The objective of the present study was to investigate the effect of $\beta-lapachone$, a quinone obtained from the bark of the lapacho tree (Tabebuia avellanedae) in South America, on the cell growth of human hepatoma (HepG2) and bladder (T24) carcinoma cells. Exposure of cancer cells to $\beta-lapachone$ resulted in growth inhibition, morphological changes and apoptosis in a concentration-dependent manner, which could be proved by MTT assay and flow cytometry analysis. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses revealed that $\beta-lapachone$ did not affect the levels of tumor suppressor p53 and cyclin-dependent kinase (Cdk) inhibitor p21 (WAFl/CIPl) expression. However, the transcriptional factor Sp-l and proliferating cell nuclear antigen (PCNA) protein levels were significantly down-regulated by $\beta-lapachone$ in both cell lines. Moreover, $\beta-lapachone$ treatment caused a dose-dependent inhibition of the expression of telomere regulatory gene products such as human telomere reverse transcriptase (hTERT) and telomerase-associated protein-l (TEP-l). Taken together, these findings suggest that $\beta-lapachone$-induced inhibition of human hepatoma and bladder carcinoma cell proliferation is associated with the induction of apoptotic cell death via modulation of several major growth regulatory gene products, and provide important new insights into the additional mechanisms of the anti-cancer activity of $\beta-lapachone$.

• FLOWER RESEARCH JOURNAL
• /
• v.19 no.4
• /
• pp.259-263
• /
• 2011

A new spray chrysanthemum (Dendranthema grandiflorum) cultivar, 'Dimple' was developed from a cross between 'champy' and 'SP05-135', by selection of seedlings and lines at the Flower Research Institute, Gyeongnam Agricultural Research and Extension Services (ARES) from 2005 to 2009. Its characteristics were investigated three times from 2007 to 2009 under condition of forcing culture in spring and retarding culture in autumn. The natural flowering time of 'Dimple' was October 24th, and year-round production was possible by day-length control. This cultivar has single type flowers with bright yellow ray floret and green center. The plant is very vigorous and very stable in the color of petals when it is cultivated even under high temperature condition in summer. Its flower was 4.7 cm in diameter, and it had 20.3 flowers per stem in autumn. The days to flowering under the short day treatment is about 50 in spring season, and 'Dimple' showed the vase life of 21.3 days in autumn. This cultivar was registered for the protection in 2009.

• Food Engineering Progress
• /
• v.21 no.2
• /
• pp.103-109
• /
• 2017

Alginate lyase from Streptomyces violaceoruber was purified by DEAE sephacel chromatography and SP sepharose chromatography. The specific activity of the purified enzyme was 14.6 units/mg protein, representing a 40.6-fold purification of the crude extract. The final preparation thus obtained showed a single band on Tricine-SDS polyacrylamide gel electrophoresis whose molecular weight was determined to be 23.3 kDa. The polyMG block of sodium alginate was hydrolyzed by the purified alginate lyase and then separated by activated carbon column chromatography and bio gel P-2 gel filtration. The main hydrolysates were composed of hetero type M/G-oligosaccharides with the degrees of polymerization (D.P.) being 6 and 8. To investigate the effects of hetero type M/G-oligosaccharides from the sodium alginate on the growth of some intestinal bacteria, cells were cultivated individually on the modified-MRS medium containing D.P. 6 and 8 M/G-oligosaccharides. B. longumgrew 4.25-fold and 6.44-fold more effectively by the treatment of D.P. 6 and 8 M/G-oligosaccharides compared with those of standard MRS medium. In addition, B. bifidumgrew 3.3-fold and 5.4-fold more effectively by the treatment of D.P. 6 and 8 M/G-oligosaccharides. In conclusion, D.P. 8 was more effective than D.P. 6 hetero M/G-oligosaccharides as regards the growth of Bifidobacteriumspp. and Lactobacillus spp.