• Applied Biological Chemistry
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• 제30권3호
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• pp.219-226
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• 1987

녹두의 자엽에서 peroxidase isozyme을 $(NH_4)_2SO_4$ 침전, Sephadex G-75, DEAE-cellulose 및 DEAE-Sephadex A-50 column chromatography 등으로 63배 정제하여 그 특성 및 결정구조를 조사하였다. Isozyme C는 Rm 값이 0.24로서 분자량이 50,000 dalton인 단량체였다. 이 효소의 반응 최적 PH는 o-dianisidine에 대하여 5.0, guaiacol에 대해서는 6.0, 반응 최적온도는 $70^{\circ}C$였으며 열에 대해서도 비교적 안정하였다. o-dianisidine과 guaiacol에 대한 Km 값은 각각 0.11mM, 60.98mM이었으며, isozyme C에 대한 기질과 cyanide는 경쟁적 저해형식을 나타내었다. Isozyme C는 평면상 직사각형의 결정구조를 하고 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권9호
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• pp.1424-1432
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• 2007

Two male, rumen fistulated crossbred Brahman-Thai native beef cattle (body weight = $400{\pm}50$ kg), fed on rice straw as a source of roughage, were used as rumen fluid sources. The treatments were $2{\times}3$ factorial arrangements; two roughages (fresh cassava foliage and cassava hay) and three sulfur levels (elemental sulfur) at 0.2 (control), 0.5 and 1% of DM, respectively. The experiment revealed that the rates (c) of gas production, ammonia-nitrogen concentration, true digestibility, total concentration or molar proportions of VFA and microbial biomass were not significantly different between cassava hay and fresh cassava foliage. However, all parameters for cassava hay were higher than for fresh cassava foliage. The supplementation of 0.5% sulfur to fresh cassava foliage resulted in a significant increase in the rate of gas production, true digestibility, total concentration of VFA, microbial biomass, rate of HCN disappearance, thiocyanate appearance and cyanide percentage conversion into thiocyanate. However, there were no effects of sulfur supplementation at 0.2, 0.5 and 1% to cassava hay. The finding suggests the utilization of cassava foliage for rumen microorganisms in terms of fermentation and HCN detoxification could be improved by sulfur supplementation of 0.5% of DM.

• 미생물학회지
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• 제44권2호
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• pp.116-121
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• 2008

Haloperoxidase를 생산하는 미생물을 분리하기 위하여 국내 연근해와 남북극 등의 해양시료에서 분리된 방선균 균주를 대상으로 탐색을 수행하여 남해 백도 해조류 추출물로부터 분리된 한 종류의 방선균(#1460)에서 높은 haloperoxidase 활성이 확인되었다. 본 균주의 생리.생화학적 특성은 Streptomyces 속과 유사하며 생산되는 haloperoxidase는 세포 조 추출물로부터 ammonium sulfate precipitation, High-Q column chromatography, gel permeation chromatography, Hydroxyapetite chromatography 그리고 hydrophobic interaction chromatography를 통하여 42%의 수율과 purification fold 70으로 정제하였다. 본 효소의 최적 반응 pH는 7이고 pH 8에서 더 높은 안정성을 보여 $60^{\circ}C$에서 1시간 반응에 효소활성의 50%가 생존한다. 또 cyanide와 azide 이온에 의해 강한 저해현상을 보인다.

• Molecules and Cells
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• 제23권3호
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• pp.370-378
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• 2007

A superoxide dismutase was purified 62-fold in seven steps to homogeneity from Methylobacillus sp. strain SK1, an obligate methanol-oxidizing bacterium, with a yield of 9.6%. The final specific activity was 4,831 units per milligram protein as determined by an assay based on a 50% decrease in the rate of cytochrome c reduction. The molecular weight of the native enzyme was estimated to be 44,000. Sodium dodecyl sulfate gel electrophoresis revealed two identical subunits of molecular weight 23,100. The isoelectric point of the purified enzyme was found to be 4.4. Maximum activity of the enzyme was measured at pH 8. The enzyme was stable at pH range from 6 to 8 and at high temperature. The enzyme showed an absorption peak at 280 nm with a shoulder at 292 nm. Hydrogen peroxide and sodium azide, but not sodium cyanide, was found to inhibit the purified enzyme. The enzyme activity in cell-free extracts prepared from cells grown in manganese-rich medium, however, was not inhibited by hydrogen peroxide but inhibited by sodium azide. The activity in cell extracts from cells grown in iron-rich medium was found to be highly sensitive to hydrogen peroxide and sodium azide. One mol of native enzyme was found to contain 1.1 g-atom of iron and 0.7 g-atom of manganese. The N-terminal amino acid sequence of the purified enzyme was Ala-Tyr-Thr-Leu-Pro-Pro-Leu-Asn-Tyr-Ala-Tyr. The superoxide dismutase of Methylobacillus sp. strain SK1 was found to have antigenic sites identical to those of Methylobacillus glycogenes enzyme. The enzyme, however, shared no antigenic sites with Mycobacterium sp. strain JC1, Methylovorus sp. strain SS1, Methylobacterium sp. strain SY1, and Methylosinus trichosproium enzymes.

• 한국광학회지
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• 제19권1호
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• pp.54-59
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• 2008

적외선 영역에서 극초단 펄스 폭을 갖는 $Cr^{4+}$:YAG 레이저를 광자 결정 광섬유에 입사하여 초 연속 스펙트럼을 갖는 광원을 얻어냈다. 이 광원을 이용하여 광통신 파장 영역에서 많은 흡수 전이선을 갖는 아세틸렌($^{12}C_2H_2$) 및 시안화 수소($H^{13}C^{14}N$) 분자의 흡수 스펙트럼을 측정하였다. 초 연속 스펙트럼을 얻기 위해 펌핑 광원으로 모드 잠금된 $Cr^{4+}$:YAG 레이저를 사용하였다. 모드 잠금된 $Cr^{4+}$:YAG 레이저는 중심파장이 1510 nm 대역에서 반복률이 100 MHz이고, 펄스폭은 75 fs이다. 모드 잠금된 $Cr^{4+}$:YAG 레이저 출력을 20 m의 광자 결정 광섬유에 집속시켜 진폭변동이 ${\pm}5dB$이하에서 400 nm 이상의 평탄한 초 연속 스펙트럼을 얻었으며, 전체적으로 한 octave 이상의 초 광대역 광원을 얻었다. 이 광원을 이용하여 50개 이상의 흡수 전이선을 갖는 아세틸렌 분자($^{12}C_2H_2$)와 시안화 수소 분자($H^{13}C^{14}N$)의 흡수 스펙트럼을 측정하고, Voigt 곡선 맞춤을 이용하여 Lorentian 성분의 흡수 선폭을 각각 측정하였다. 이와 같은 초 광대역 광원의 스펙트럼을 이용하면 O, S, C, L 밴드와 같은 대역에 존재하는 분자의 흡수 스펙트럼 측정에 있어 유용하게 사용될 수 있다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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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.

• 센서학회지
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• 제17권2호
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• pp.143-146
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• 2008

Polymer-coated film SAW sensors have been fabricated and their sensing properties for toxic chemicals have been extensively investigated. Four types of the toxic chemical compounds of hydrogen cyanide(AC), carbonyl dichloride(CG), pinacolyl methylfluorophosphonate(GD), 2,2'-dichlorodiethylthio ether(HD) were used as target gases. SAW sensors using five different kinds of polymers were used to detect toxic chemicals and their gas sensing characteristics were investigated. The polymers used as the sensing materials were polyisobutylene(PIB), polyepichlorohydrin(PECH), polydimethylsiloxane(PDMS), polybutadiene(PBD) and polyisoprene(PIP). The recommendable mixing ratio of PIB, PECH, PDMS, PBD and PIP to solvents were 1:30, 1:40, 1:10, 1:30 and 1:30, respectively. The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.

• The Plant Pathology Journal
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• 제34권3호
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• pp.241-249
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• 2018

Commercial biocontrol of microbial plant diseases and plant pests, such as nematodes, requires field-effective formulations. The isolate Pseudomonas chlororaphis O6 is a Gram-negative bacterium that controls microbial plant pathogens both directly and indirectly. This bacterium also has nematocidal activity. In this study, we report on the efficacy of a wettable powder-type formulation of P. chlororaphis O6. Culturable bacteria in the formulated product were retained at above $1{\times}10^8$ colony forming units/g after storage of the powder at $25^{\circ}C$ for six months. Foliar application of the diluted formulated product controlled leaf blight and gray mold in tomato. The product also displayed preventative and curative controls for root-knot nematode (Meloidogyne spp.) in tomato. Under laboratory conditions and for commercially grown melon, the control was at levels comparable to that of a standard commercial chemical nematicide. The results indicated that the wettable powder formulation product of P. chlororaphis O6 can be used for control of plant microbial pathogens and root-knot nematodes.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.271-275
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• 1999

The intracellular superoxide dismutase (SOD) from Staphylococcus sciuri was isolated to homogeneity by continuous steps, including ammonium sulfate fractionation, DEAE-ion-exchange chromatography, gel filtration, and phenyl hydrophobic gel chromatography. Pure SOD had a specific activity of 4,625 U/mg and was purified 158-fold with a yield of 31 % from a cell free extract. The molecular weight of the purified SOD was determined to be approximately 35.5 kDa by gel filtration and the enzyme was also shown to be composed of dimeric subunits on denaturing SDS-PAGE. The enzyme activity remained stable at pH 5 to 11 and also to heat treatment of up to $50^{\circ}C$ at pH 7.8, with 80% relative activity. The enzyme was insensitive to cyanide, hydrogen peroxide, and azide, indicating that it is a manganese-containing SOD. The EPR spectrum showed the enzyme containing manganese as a cofactor.

• 식물병연구
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• 제24권2호
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• pp.162-169
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• 2018

The GacS/GacA system in the root colonizer Pseudomonas chlororaphis O6 is a key regulatory system of many traits relevant to the plant probiotic nature of this bacterium. The work in this paper elucidates proteins using proteomics approach in P. chlororaphis O6 under the control of the cytoplasmic regulatory protein, GacA. A gacA mutant of P. chlororaphis O6 showed loss in production of phenazines, acyl homoserine lactones, hydrogen cyanide, and protease, changes that were associated with reduced in vitro antifungal activity against plant fungal pathogens. Production of iron-chelating siderophore was significantly enhanced in the gacA mutant, also paralleling changes in a gacS mutant. However, proteomic analysis revealed proteins (13 downregulated and 7 upregulated proteins in the mutant compared to parental strain) under GacA control that were not apparent by a proteomic study of a gacS mutant. The putative identity of the downregulated proteins suggested that a gacA mutant would have altered transport potentials. Notable would be a predicted loss of type-VI secretion and PEP-dependent transport. Study of mutants of these GacA-regulated proteins will indicate further the features required for probiotic potential in this rhizobacterium.