• Title/Summary/Keyword: sigma factor

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Isolation and characterization of sigH from Corynebacterium glutamicum (Corynebacterium glutamicum의 sigH 유전자의 분리 및 기능분석)

  • Kim Tae-Hyun;Kim Hyung-Joon;Park Joon-Sung;Kim Younhee;Lee Heung-Shick
    • Korean Journal of Microbiology
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    • v.41 no.2
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    • pp.99-104
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    • 2005
  • Corynebacterial clones which exert regulatory effects on the expression of the glyoxylate bypass genes were isolated using a reporter plasmid carrying the enteric lacZ fused to the aceB promoter of Corynebacterium glutamicum. Some clones carried common fragments as turned out by DNA mapping technique. Subcloning analysis followed by the measurement of $\beta-galactosidase$ activity in Escherichia coli identified the region responsible for the aceB-repressing activity. Sequence analysis of the DNA fragment identified two independent ORFs of ORF1 and ORF2. Among them, ORF2 was turned out to be responsible for the aceB-repressing activity. ORF1 encoded a 23,216 Da protein composed of 206 amino acids. Sequence similarity search indicated that the ORF may encode a ECF-type $\sigma$ factor and designated sigH. To identify the function of sigH, C. glutamicum sigH mutant was constructed by gene disruption technique and the sigH mutant showed growth retardation as compared to the wild type strain. In addition, the mutant strain showed sensitivity to oxidative-stress generating agent plumbagin. This result imply that sigH is probably involved in the stress response occurring during normal cell growth.

Image Optimization of Fast Non Local Means Noise Reduction Algorithm using Various Filtering Factors with Human Anthropomorphic Phantom : A Simulation Study (인체모사 팬텀 기반 Fast non local means 노이즈 제거 알고리즘의 필터링 인자 변화에 따른 영상 최적화: 시뮬레이션 연구)

  • Choi, Donghyeok;Kim, Jinhong;Choi, Jongho;Kang, Seong-Hyeon;Lee, Youngjin
    • Journal of the Korean Society of Radiology
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    • v.13 no.3
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    • pp.453-458
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    • 2019
  • In this study we analyzed the tendency of the image characteristic by changing filtering factor for the proposed fast non local means (FNLM) noise reduction algorithm with designed Male Adult mesh (MASH) phantom through Geant4 application for tomographic emission (GATE) simulation program. To accomplish this purpose, MASH phantom for human copy was designed through the GATE simulation program. In addition, we acquired degraded image by adding Gaussian noise with a value of 0.005 using the MATALB program in MASH phantom. Moreover, in degraded image, the FNLM noise reduction algorithm was applied by changing the filtering factors, which set to 0.005, 0.01, 0.05, 0.1, 0.5, and 1.0 value, respectively. To quantitatively evaluate, the coefficient of variation (COV), signal to noise ratio (SNR), and contrast to noise ratio (CNR) were calculated in reconstructed images. Results of the COV, SNR and CNR were most improved in image with a filtering factor of 0.05 value. Especially, the COV was decreased with increasing filtering factor, and showed nearly constant values after 0.05 value of the filtering factor. In addition, SNR and CNR were showed that improvement with increasing filtering factor, and deterioration after 0.05 value of the filtering factor. In conclusion, we demonstrated the significance of setting the filtering factor when applying the FNLM noise reduction algorithm in degraded image.

Differentially Up-expressed Genes Involved in Toluene Tolerance in Pseudomonas sp. BCNU106 (유기용매 내성 세균 Pseudomonas sp. BCNU106 균주에서 차별적으로 상향 발현되는 유전자군의 톨루엔 내성과의 연관성)

  • Joo, Woo Hong;Bae, Yun-Ui;Kim, Da Som;Kim, Dong Wan
    • Journal of Life Science
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    • v.30 no.1
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    • pp.88-95
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    • 2020
  • Using a random arbitrarily primed polymerase chain reaction, messenger RNA expression levels were assessed after exposure to 10% (v/v) toluene for 8 hr in solvent-tolerant Pseudomonas sp. BCNU 106. Among the 100 up-expressed products, 50 complementary DNA fragments were confirmed to express repeatedly; these were cloned and then sequenced. Blast analysis revealed that toluene stimulated an adaptive increase in the gene expression level in association with transcriptions such as LysR family of transcriptional regulators and RNA polymerase factor sigma-32. The expression of catalase and Mn2+/Fe2+ transporter genes functionally associated with inorganic ion transport and metabolism increased, and the increased expression of type IV pilus assembly PilZ and multi-sensor signal transduction histidine kinase genes, functionally categorized into signal transduction and mechanisms, was also demonstrated under toluene stress. The gene expression level of beta-hexosaminidase in association with carbohydrate transport and metabolism increased, and those of DNA polymerase III subunit epsilon, DNA-3-methyladenine glycosylase II, DEAD/DEAH box helicase domain-containing protein, and ABC transporter also increased after exposure to toluene in DNA replication, recombination, and repair, and even in defense mechanism. In particular, the RNAs corresponding to the ABC transporter, Mn2+/Fe2+ transporter, and the β-hexosaminidase gene were confirmed to be markedly induced in the presence of 10% toluene. Thus, defense mechanism, cellular ion homeostasis, and biofilm formation were shown as essential for toluene tolerance in Pseudomonas sp. BCNU 106.

A study on the process optimization of microcellular foaming injection molded air-conditioner drain pen (화학적 초미세 발포 사출성형을 이용한 에어컨 드레인 펜의 공정 최적화에 대한 연구)

  • Kim, Joo-Kwon;Kwak, Jae-Seob;Kim, Jun-Min;Lee, Jun-Han;Kim, Jong-Sun
    • Design & Manufacturing
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    • v.11 no.2
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    • pp.1-8
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    • 2017
  • In this study, we applied microcellular foaming injection molding process to improve the performance of system air-conditioner drain fan which had been produced by injection molding process and studied the optimization of process conditions through 6-sigma process and response surface method (RSM) to reduce weight and deformation of products. Additive type, melt temperature, mold temperature, and injection screw shape were selected as the factor affecting the weight and deformation of the products by carrying out analysis of trivial many through ANOVA and design of experiment (DOE) method. Among the effect factor, we set the addictive type to Long G/F and screw shape to foaming screw which had the highest level of weight reduction and deformation reduction. The amount of foaming agent gas was set at 60 ml, which was the limit beyond which the weight of product did not decrease any more. For melt temperature and mold temperature, we studied the conditions where both weight and deformation were minimized using the RSM. As a result, we set the melt temperature to $250^{\circ}C$, fixed mold temperature to $20^{\circ}C$, and moving mold temperature to $40^{\circ}C$. The improvement effect was analyzed by appling the selected optimal conditions to the production process using the microcellular foaming injection molding. The results showed that the mean weight of product was measured to be 1,420g which was 19% lower than that measured in the current process. The standard deviations of the weights were found to be similar to those in the current process and it showed a low dispersion. The mean deformation was measured to be 0.9237mm, which represented a 57% reduction compared to the mean deformation in the current process, and the standard deviation decreased from 0.3298mm to 0.1398mm. Moreover, we analyzed the process capability for deformation, and the results showed that the short-term process capability increased from 2.73 to 6.60 which was even higher than targeted level of 6.0.

A Study on the Slope Stability Analysis by Shearing Reinforcement of Vegetation Roots -Focused on the Pinus Koraiensis Roots- (식생뿌리의 전단강도 보강에 의한 사면안전율 해석 -잣나무 뿌리를 중심으로-)

  • 조주형;이종성
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.5
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    • pp.80-93
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    • 2000
  • This study measured the shearing resistance of the roots of the Pinus Koraiensis by the tensile strength gained through their individual tensile test for the Root Reinforcement Model. On the basis of the shearing resistance value calculated through such a process the factor of safety(Fs) was comparatively presented by using the simplified Janbu Method in PCSTABL5M, the slop-analyzing software which had been developed in Purdue University of the U.S.A according to the shape of a slope and the type of soil. The results to have measured a stress and the factor of safety(Fs) by experiment are as follows. 1) The mean root diameter of the Pinus Koraiensis used for this experiment was 2.483mm and the mean tensile stress was calculated as 422.846(kgf/$\textrm{cm}^2$). In the strain ratio of material and the elastic modulus was measured 7.8%, 9,291.92(kgf/$\textrm{cm}^2$). 2) The shearing strength including the resistance of soil and root is expressed as Rt=C+Cr+$\sigma$.tan . ΔCr(kg/$\textrm{cm}^2$) of the shearing resistance calculated by estimating the areal ratio of roots at 10 is 0.253(kgf/$\textrm{cm}^2$). 3) As the result of making an analysis of the natural slope stability by the soil parameter, the factor of safety(Fs) was calculated at 1.795 in CL, and the stability analysis of the root reinforcement slope, Fs was calculated at 1.952. However, since a precise analysis of the controlled factors of the slope analyses are demanded for more accurate dynamic analyses, the future demands a study on this.

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The global regulator GacS of a biological bacterium Pseudomonas chlororaphis O6 regulates expression of the stationary-phase sigma factor rpoS and reduces survival in oxidative stress.

  • Kang, Beom-Ryong;Cho, Baik-Ho;Kim, Young-Cheol
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2003.10a
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    • pp.100.2-101
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    • 2003
  • The global regulator, GacS (global antibiotic and cyanide sensor kinase), was required for the increased resistance to hydrogen peroxide occurring as cultures of the rhizobacterium, P. chlororaphis O6, matured. Specific stationary-phase peroxidase and catalase isozymes were absent in the GacS mutant, whereas a manganese-superoxide dismutase isozyme was expressed earlier and to a great extent than wild type. In the wild type cell, transcript accumulation of rpoS was higher in late logarithmic-phase cells than cells from mid logarithmic- or stationary-phase. Transcripts from rpoS in the GacS mutant were reduced in each of these growth phases compared to the wild type expression. The down stream sequence from rpoS lacked sequences encoding a small RNA, rsmZ, found in other pseudomonads and implicated in control of genes activated by the GacS system. These findings suggest that GacS-mediated regulation of RpoS plays role in control of oxidative stress in P. chlororaphis O6 by as yet an unknown mechanism.

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Spring Dominant Copepods and Their Distribution Pattern in the Yellow Sea

  • Kang, Jung-Hoon;Kim, Woong-Seo
    • Ocean Science Journal
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    • v.43 no.2
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    • pp.67-79
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    • 2008
  • We investigated the relationship between mesoscale spatial distribution of environmental parameters (temperature, salinity, and sigma-t), chlorophyll-a concentration and mesozooplankton in the Yellow Sea during May 1996, 1997, and 1998, with special reference to Yellow Sea Bottom Cold Water (YSBCW). Adult calanoid copepods, Calanus sinicus, Paracalanus parvus s.l., Acartia omorii, and Centropages abdominalis were isolated by BVSTEP analysis based on the consistent explainable percentage (-32.3%) of the total mesozooplankton distributional pattern. The copepods, which accounted for 60 to 87% of the total abundances, occupied 73-78% of the copepod community. The YSBCW consistently remained in the northern part of the study area and influenced the spatial distribution of the calanoid copepods during the study periods. Abundances of C. sinicus and P. parvus s.l., which were high outside the YSBCW, were positively correlated with the whole water average temperature (p<0.01). In contrast, the abundances of C. abdominalis and A. omorii, which were relatively high in the YSBCW, were associated with the integrated chl-a concentration based on factor analysis. These results indicate that the YSBCW influenced the mesoscale spatial heterogeneity of average temperature and integrated chl-a concentration through the water column. This consequently affected the spatial distribution pattern of the dominant copepods in association with their respective preferences for environmental and biological parameters in the Yellow Sea during spring.

The study of the $BiO_{6}$ octahedra structure in superconducting $Ba_{0.6}K_{0.4}BiO_3$ single crystal by extended x-ray absorption spectroscopy (EXAFS에 의한 $Ba_{0.6}K_{0.4}BiO_3$ 단결정의 초전도 상태에서 $BiO_{6}$ octahedra 구조의 연구)

  • 김봉준;김영철;김현탁;강광용;이재민
    • Progress in Superconductivity
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    • v.4 no.2
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    • pp.148-152
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    • 2003
  • We have observed the temperature dependences of Bi $L_{III}$ edge spectra by extended X-ray absorption spectroscopy for a high quality single crystal and a powder of the $Ba_{0.6}K_{0.4}BiO_3$ superconductor. $Ba_{0.6}K_{0.4}BiO_3$ has the cubic structure and metallic states. The deformation of the $BiO_{6}$ octahedra, which is due to the anomalies of the Bi-O and Bi-Ba bond length, was showed by the double-shell fit. It was clearly found that these anomalies are owing to the difference in the strength of Bi-O bonds. The temperature dependences of both bond lengths and the Debye-Walter factor ${\sigma}^2$ of the Bi-O and Bi-(Ba,K) bond are discussed to illustrate local structural features of the $Ba_{0.6}K_{0.4}BiO_3$

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A Delphi Approach to the Development of an Integrated Performance Measurement and Management Model for a Car Assembler

  • Shawyun, Teay
    • Industrial Engineering and Management Systems
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    • v.7 no.3
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    • pp.214-227
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    • 2008
  • Today's dynamic competitiveness requires an organization to improve its performance measurement and management. Quality Management Systems (QMS) abound, the main ones being: ISO series, Malcolm Baldridge National Quality Award (MBNQA), European Forum for Quality Management (EFQM), Six Sigma Business Scorecard and the Balanced Scorecard. Based on the literature, the IPMMM (Integrated Performance Measurement and Management Model) identified 7 key synthesized factors: leadership, strategy management and policy, customer and market, learning and growth, partnership and resources, internal processes and business results that are employed to investigate the key performance indicators of a car assembler using the Delphi methodology. In the 2 rounds of Delphi panels consisting of 20 senior management personnel, the $1^{st}$ round of 198 indicators in the IPMMM yielded 90 indicators. The $2^{nd}$ round yielded 43 performance indicators with 18 rated as critical based on the % assigned in the $1^{st}$ and $2^{nd}$ priority rating of "very important factor" and "key performance indicator" that must be ranked high on both of the priorities. The very critical indicators appeared to be: defect percentage and first time capability (tie in $1^{st}$ place) and revenue, goal setting, customer satisfaction index, on-time delivery, brand image, return on investment, Claim Occurrence Ratio, and debt being ranked from $3^{rd}$ to $10^{th}$. It can be surmised that an organization can identify and develop an appropriate set of performance indicators through the Delphi methodology and implement and manage them based on the Balanced Scorecard.

Targeting the Osmotic Stress Response for Strain Improvement of an Industrial Producer of Secondary Metabolites

  • Godinez, Octavio;Dyson, Paul;del Sol, Ricardo;Barrios-Gonzalez, Javier;Millan-Pacheco, Cesar;Mejia, Armando
    • Journal of Microbiology and Biotechnology
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    • v.25 no.11
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    • pp.1787-1795
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    • 2015
  • The transition from primary to secondary metabolism in antibiotic-producing Streptomyces correlates with expression of genes involved in stress responses. Consequently, regulatory pathways that regulate specific stress responses are potential targets to manipulate to increase antibiotic titers. In this study, genes encoding key proteins involved in regulation of the osmotic stress response in Streptomyces avermitilis, the industrial producer of avermectins, are investigated as targets. Disruption of either osaBSa, encoding a response regulator protein, or osaCSa, encoding a multidomain regulator of the alternative sigma factor SigB, led to increased production of both oligomycin, by up to 200%, and avermectin, by up to 37%. The mutations also conditionally affected morphological development; under osmotic stress, the mutants were unable to erect an aerial mycelium. In addition, we demonstrate the delivery of DNA into a streptomycete using biolistics. The data reveal that information on stress regulatory responses can be integrated in rational strain improvement to improve yields of bioactive secondary metabolites.