• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.819-824
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• 2001

The principal DNA modification systems of the amino-acid-producing bacteria Corynebacterium glutamicum AS019, Brevibacterium flavum BF4, and B. lactofermentum BL1 was investigated using two approaches; digestion of plasmid DNA isolated from these species TseI and Fnu4HI, and sequence analysis of the putative methyltransferase target sites following the derivatization of DNA using metabisulfite treatment. The C. glutamicum and B. flavum strains showed similar digestion patterns to the two enzymes, indicating that the target for cytidine methyltransferase recognizes 5'-GCSGC-3'(where S is either G or C). Mapping the methylated cytidine sites by bisulfite derivatization, followed by PCR amplification and sequencing, was only possible when the protocol included an additional step eliminating any underivatized DNA after PCR amplification, thereby indicating that the derivatization was not $100\%$ efficient. This may have been due to the high G0C content of this genus. It was confirmed that C. glutamicum AS019 and B. flavum BF4 methylated the cytidine in the $Gm^5CCGC$ sequences, yet there were no similar patterns of methylation in B. lactofermentum, which was consistent with the distinctive degradation pattern seen for the above enzymes. These findings demonstrate the successful application of a modified bisulfite derivatization method with the Corynebacterium species for determining methylation patterns, and showed that different species in the geneus contain distinctive restriction and modification systems.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.57-65
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• 1999

Generation of gaseous ammonia has been a major problem in composting facilities. Microbial inocula. KMT-199(brand name: CompoBac$^{TM}$). was developed in INBI0NET CORPORATION and tested in the field for its ammonia reducing capability. When KMT-199 was applied. a ten-fold increase of mesophilic and thermophilic microorganisms was observed during the early stage of composting process. Also. the temperature and pH of early stage compost increased at a higher rate when compared to control. KMT-199 treated compost reached highest temperature of $75^{\circ}C$at day 9, indicating treatment could shift the maximum composting temperature to 3 days earlier The highest temperature also reached $3^{\circ}C$ higher than the control. The pH of compost gradually increased during composting. KMT-199 treated compost reached a plateau of pH 9.32 at day 15 after treatment, and then slowly decreased thereafter. On the other hand. pH of the control steadily increased until day 38 of composting. 29% reduction of gaseous ammonia generation during composting was observed compared to that of the control. KMT-199 amended compost resulted in a higher germination rate of radish seeds than the control. These results indicate that application of microbial inocula facilitates degradation of organic materials, including ammonia during the composting process.

• Advances in environmental research
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• v.4 no.4
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• pp.247-262
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• 2015

The few lignin biomarker studies conducted in tropical environments are hampered by having to use references signatures established for plants and soils characteristic of the temperate zone. This study presents a lignin biomarker analysis (vanillyls (V), p-hydroxyls (P), syringyls (S), cinnamyls (C)) of the dominant plant species and soil horizons as well as an analysis of the interrelated terrigenous organic matter (TOM) dynamics between vegetation and soil of the $Tapaj{\acute{o}}s$ river region, an active colonization front in the Brazilian Amazon. We collected and analyzed samples from 17 fresh dominant plant species and 48 soil cores at three depths (0-5 cm, 20-25 cm, 50-55 cm) from primary rainforest, fallow forest, subsistence agriculture fields and pastures. Lignin signatures in tropical plants clearly distinguish from temperate ones with high ratios of Acid/aldehyde of vanillyls ((Ad/Al)v) and P/V+S. Contrary to temperate environments, similarly high ratios in tropical soils are not related to TOM degradation along with pedogenesis but to direct influence of plants growing on them. Lignin signatures of both plants and soils of primary rainforest and fallow forest clearly distinguish from those of non-forested areas, i.e., agriculture fields and pastures. Attalea speciosa Palm trees, an invasive species in all perturbed landscapes of the Amazon, exhibit lignin signatures clearly distinct from other dominant plant species. The study of lignin signatures in tropical areas thus represents a powerful tool to evaluate the impact of primary rainforest clearing on TOM dynamics in tropical areas.

• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.72-77
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• 2010

Alginate lyases, also known as alginases or alginate depolymerases, catalyze the degradation of alginate by a ${\beta}$-elimination mechanism that has yet to be fully elucidated. Alginate is a copolymer of ${\alpha}$-L-guluronate (G) and its C5 epimer ${\beta}$-D-mannuronate (M), arranged as homopolymeric G blocks, M blocks, alternating GM or random heteropolymeric G/M stretches. Almost all alginate lyases depolymerize alginate in an endolytical fashion via a ${\beta}$-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. Till now there is no crystal structure available for this class of proteins. Since there is no template with high sequence identity, three-dimensional coordinates for exotype alginate lyase (PL 15 family) were determined using modeling methods (Comparitive modeling and Fold recognition). The structures were modeled using the X-ray coordinates from Heparinase protein family (PDB code: 3E7J). This enzyme (Atu3025) displays enzymatic activity for both poly-M and poly-G alginate. Since poly-M is widespread; docking of a tri-mannuronate against the modeled structure was performed. We identified some of those residues which are crucial for lyase activity. The results from this study should guide future mutagenesis studies and also provides a starting point for further proceedings.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.470-477
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• 2018

With a highly functional methyl vinyl silicone rubber (VMQ) matrix and filler materials of $B_4C$, PbO, and benzophenone (BP) and through powder surface modification, silicone rubber mixing, and vulcanized molding, a flexible radiation shielding and resistant composite was prepared in the study. The dispersion property of the powder in the matrix filler was improved by powder surface modification. BP was added into the matrix to enhance the radiation resistance performance of the composites. After irradiation, the tensile strength, elongation, and tear strength of the composites decreased, while the Shore hardness of the composites and the crosslinking density of the VMQ matrix increased. Moreover, the composites with BP showed better mechanical properties and smaller crosslinking density than those without BP after irradiation. The initial degradation temperatures of the composites containing BP before and after irradiation were $323.6^{\circ}C$ and $335.3^{\circ}C$, respectively. The transmission of neutrons for a 2-mm thick sample was only 0.12 for an Am-Be neutron source. The transmission of ${\gamma}$-rays with energies of 0.662, 1.173, and 1.332 MeV for 2-cm thick samples were 0.7, 0.782, and 0.795, respectively.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.105-109
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• 2005

Heat Shock Transcription Factor (HSF), and the promoter heat Shock Element (HSE), are among the most highly conserved transcriptional regulatory elements in nature. HSF mediates the transcriptional response of eukaryotic cells to heat, infection and inflammation, pharmacological agents, and other stresses. While HSF is essential for cell viability in yeast, oogenesis and early development in Drosophila, extended life-span in C. elegans, and extra-embryonic development and stress resistance in mammals, little is known about its full range of biological target genes. We used whole genome analyses to identify virtually all of the direct transcriptional targets of yeast HSF, representing nearly three percent of the genomic loci. The majority of the identified loci are heat-inducibly bound by yeast HSF, and the target genes encode proteins that have a broad range of biological functions including protein folding and degradation, energy generation, protein secretion, maintenance of cell integrity, small molecule transport, cell signaling, and transcription. Approximately 30% of the HSF direct target genes are also induced by the diauxic shift, in which glucose levels begin to be depleted. We demonstrate that phosphorylation of HSF by Snf1 kinase is responsible for expression of a subset of HSF targets upon glucose starvation.

• Journal of Powder Materials
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• v.16 no.4
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• pp.262-267
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• 2009

Disk type porous nickel membrane was fabricated by in-situ reduction/sintering process using compacted NiO/PMMA (PMMA; Polymethyl methacrylate) mixture at $800^{\circ}C$ in hydrogen atmosphere. The porosity (49$\sim$58%) of these membrane was investigated as an amount of PMMA additive. The thermal decomposition and reduction behavior of NiO/PMMA were analyzed by TG/DTA in hydrogen atmosphere and the activation energy for the hydrogen reduction of NiO and thermal degradation of PMMA was calculated as 61.1 kJ/mol, evaluated by Kissinger method. Finally, the filtering performance and pressure drop were measured by particle counting system.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.211-223
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• 2017

In this work, an attempt was made to compare the effects of UV irradiation on the intrinsic and separation properties of membranes made of two different polymeric materials, i.e., polyvinylidene fluoride (PVDF) and polyetherimide (PEI). The changes on membrane structural morphologies and chemical characteristics upon UV-A exposure (up to 60 h) were studied by FESEM and FTIR, respectively. It was found that cracks and fractures were detected on the PVDF-based membrane surface when the membrane was exposed directly to UV light for up to 60 h. Furthermore, the mechanical strength and thermal stability of irradiated PVDF-based membrane was reported to decrease with increasing UV exposure time. The PEI membrane surface meanwhile remained almost intact throughout the entire UV irradiation process. Filtration experiments showed that the permeate flux of UV-irradiated PVDF membrane was significantly increased from approximately 11 to $16L/m^2.h$ with increasing UV exposure time from zero to 60 h. Oil rejection meanwhile was decreased from 98 to 85%. For the PEI-based membrane, oil rejection of >97% was recorded and its overall structural integrity was marginally affected throughout the entire UV irradiation process. The findings of this work showed that the PEI-based membrane should be considered as the host for photocatalyts incorporation if the membrane was to be used for UV-assisted wastewater treatment process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.2
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• pp.254-266
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• 1996

Boiling heat transfer coefficients of pure refrigerants(R22, R32, R125, R134a, R290, and R600a) and refrigerant mixtures(R32/R134a and R290/R600a) are measured experimentally and compared with several correlations. Convective boiling term of Chen's correlation predicts experimental data for pure refrigerants fairly well(root-mean-square error of 12.1% for the quality range over 0.2). An analysis of convective boiling heat transfer of refrigerant mixtures is performed for an annular flow to study degradation of heat transfer. Annular flow is the subject of this analysis because a great portion of the evaporator in refrigeration or air conditioning system is known to be in the annular flow regime. Mass transfer effect due to composition difference between liquid and vapor phases, which is considered as a driving force for mass transfer at interface, is included in this analysis. Correction factor $C_F$ is introduced to the correlation for the pure substances through annular flow analysis to apply the correlation to the mixtures. The flow boiling heat transfer coefficients are calculated using the correlation considering nucleate boilling effect in the low quality region and mass transfer effect for nonzazeotropic refrigerant mixtures.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.4
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• pp.1-7
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• 2007

Flow rate is one of the important variables for precise motion control and detection of the faults and fluid loss in many hydraulic components and systems. But in many cases, it is not easy to measure it directly. The orifice area of a servo valve by which the fluid flows is one of key factors to monitor the flow rate. In this paper, we have constructed an estimation algorithm for the effective orifice area by using the model of a servo valve cylinder control system and Kalman filter algorithm. Without geometry information about the servo valve, it is shown that the effective orifice area can be estimated by using only displacement and pressure data corrupted with noise. And the effect of the biased sensor data and system parameter errors on the estimation results are discussed. The paper reveals that sensor calibration is important in accurate estimation and plausible parameter data such as oil bulk modulus and actuator volume are acceptable for the estimation without any error. The estimation algorithm can be used as an useful tool for detecting leakage, monitoring malfunction and/or degradation of the system performance.