• Title/Summary/Keyword: levan

Search Result 81, Processing Time 0.025 seconds

Occurrence of bacterial canker of sweet cherry caused by Pseudomonas syringae pv. morsprunorum

  • Kim, G. H.;I. S. Nou;Y. J. Koh
    • Proceedings of the Korean Society of Plant Pathology Conference
    • /
    • 2003.10a
    • /
    • pp.98.2-99
    • /
    • 2003
  • Bacterial canker of sweet cherry (Prunus cerasus L.) was observed in farmers' orchard in Goesan, Chungbuk in 2003. Typical canker symptom occurred on the branches or twigs of sweet cherry in early spring and bacterial exudates oozed out of the cracked barks of diseased trees. Watersoaked brown symptom appeared on the leaves and severe infection caused thorough defoliation on the branches or twigs of sweet cherry. When cut the severely infected branches or twigs, irregular and rusty-colored symptoms in sapwood and heartwood were clearly found, indicating that they could serve as specific symptoms of bacterial canker of sweet cherry. The gram negative, aerobic bacterium isolated from the lesion produced fluorescent pigments on King's B agar medium but did not grow at 37$^{\circ}C$ The bacterium formed Levan-type colonies, and showed negative reactions in oxidase reaction, arginine dihydrolysis test, and pectolytic activity Based on the biochemical and pathological characteristics, the causal organism was identified as Pseudomonas syringae pv. morsprunorum. This is the first report on bacterial canker of sweet cherry in Korea.

  • PDF

The Method for the Study of Human Chromosome (人間의 染色體 硏究法)

  • Kang, Yung Sun
    • The Korean Journal of Zoology
    • /
    • v.13 no.2
    • /
    • pp.35-43
    • /
    • 1970
  • 사람은 물론 모든 생물의 體細胞는 여러 타입의 染色體를 이중으로 지니고 있어서 倍數(diploid number)라하고 生殖細胞는 그의 한쪽만을 갖어서 半數(haploid number)라 한다. 1956년에 이르기까지도 사람의 染色體의 倍數는 48로 알려지고 性染色體 구성은 확실하지 못한 상태에 있었다. 1956년 이래 體細胞 染色體 硏究에 관한 기술 방법의 비약적인 발전으로 인하여 사람의 정상인 核型은 물론 異常形質을 나타내는 個體의 染色體에 관해서도 정확한 데타를 얻을 수 있게 되었다. 染色體硏究에 있어 개선된 기술방벙의 가장 큰 것은 組織培養의 도입이다. 종래의 切片作成法(section method)을 지양하고, 사람 몸에서 지극히 적은 분량의 組織을 얻어가지고 生體에서와 거의 비슷한 환경을 주어 인공적으로 단층의 細胞를 이루어 증식시키는 방법이다. 1956년 사람의 染色體를 정확히 파악하여 倍數로 46개이며, 남자는 XY, 여자는 XX 의 性染色體를 지닌다는 점을 밝힌 Tjio 및 Levan도 사람의 胎兒의 肺組織을 培養한 것을 재료로 삼았던 것이다.

  • PDF

Evaluation of Radical Scavenging Activity and Physical Properties of Textured Vegetable Protein Fermented by Solid Culture with Bacillus subtilis HA According to Fermentation Time (고초균을 이용한 조직대두단백의 고체 발효 기간에 따른 라디칼 소거 활성 및 물성 평가)

  • Kim, Ji-Eun;Lee, Sam-Pin
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.39 no.6
    • /
    • pp.872-879
    • /
    • 2010
  • Textured vegetable protein (TVP) was fermented by the solid-state fermentation using Bacillus subtilis HA and biologically active compounds were produced by fermentation for 7 days. The longer fermentation time resulted in the color change of fermented TVP with strong dark red and yellow color. Melanoidin production rapidly increased until fermentation for 48 hr, but did change afterwards. The 70% ethanol extract of TVP fermented for 24 hr showed higher DPPH radical scavenging effect with $IC_{50}$ of 0.99 mg/mL but longer fermentation did not increase its activity. Also, 70% ethanol extract of TVP fermented for 72 hr indicated higher ABTS radical scavenging effect with $IC_{50}$ of 1.68 mg/mL. Consistency index in TVP fermented for 48 hr was the highest values with 7.89 $Pa{\cdot}s^n$. Viscoelastic properties of TVP fermented for 48 hr were maximally enhanced, and viscous value (G") is higher than the elastic value (G'). The $\gamma$-polyglutamic acid (PGA) content was increased by increasing fermentation time with 37.72% of $\gamma$-PGA at 168 hr. However, levan content and molecular weight of PGA were decreased with increasing fermentation time from 7.83% to 3.91% and 1649.3 kDa to 1286.8 kDa, respectively.

THE INHIBITORY EFFECT OF FRUCTAN-PRODUCING S. SALIVARIUS ON THE FORMATION OF ARTIFICIAL PLAQUE (Fructan 생성 S. salivarius의 인공치태 억제효과)

  • Park, So-Yung;Park, Eun-Hae;Oh, Jong-Suk;Yang, Kyu-Ho
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.30 no.1
    • /
    • pp.25-32
    • /
    • 2003
  • S. mutans is the most important causative bacteria of dental caries among the oral bacteria. S. salivarius is a normal inhabitant in the human oral cavity. Nine strains of S. salivarius in this study were isolated from the oral cavities of children and identified, and their effect on S. mutans and S. oralis was studied. 1. The mean weight of produced artificial plaque on the wires in the beaker was 204.9 mg in the culture of S. mutans only, whereas being reduced to 1.9 mg through 20.6mg in the combined culture of S. mutans and each S. salivarius isolate (p<0.05). The viable cell didn't show the difference between them after culturing. 2. When S. mutans was cultured in the media containing culture supernatant of each S. salivarius isolate in M17 broth, the mean weight of produced artificial plaque was 117.1 mg on the wires, whereas being 47.7 mg in the media containing culture supernatant of each S. salivarius isolate in M17 broth containing 5% sucrose. 3. The polymer produced by S. salivarius isolates was on the thin layer chromatography. 4. Inulin and levan didn't inhibit the formation of artificial plaque by S. mutans in the beaker test. These results suggested that fructan-producing S. salivarius isolates inhibited the formation of artificial plaque by S. mutans.

  • PDF

Effect of High-Molecular Weight Organic Compounds on Improvement of Pore Structure of Cement Materials

  • Lee, Woong-Geol;Jeon, Se-Hoon;Song, Myong-Shin;Kim, Jusung
    • Journal of the Korean Ceramic Society
    • /
    • v.56 no.6
    • /
    • pp.534-540
    • /
    • 2019
  • Carbon dioxide emissions involved in global warming are one of the most important issues in the world, and carbon dioxide emissions from the cement industry are about 7% of total carbon dioxide emissions. Thus, reduction in the amount of utilized cement can contribute to a reduction of carbon dioxide emissions. The average life of concrete is 20 ~ 30 years, and if concrete life can be improved by ten years, cement use will be much lower. In this study, we examined the use and effect of fructan from microbes as a method for the densification of the pore structure of cement. The effect of fructan on the hydration reaction and pore distribution, as well as the water absorption of hardened cement mortar were studied. Pores distribution increased in mesopore OPC, and absorption rate was found to decrease with the use of fructan, which has a glue-like and swelling character.

Characterization of Mucilage Produced from the Solid-state Fermentation of Soybean Grit by Bacillus firmus

  • Jang, Eun-Kyung;Seo, Ji-Hyun;Park, Seung-Chun;Yoo, Byoung-Seung;Lee, Sam-Pin
    • Food Science and Biotechnology
    • /
    • v.16 no.5
    • /
    • pp.722-727
    • /
    • 2007
  • Mucilage containing ${\gamma}-polyglutamic$ acid (PGA) was efficiently generated by the solid-state fermentation (SSF) of soybean grit by Bacillus firmus NA-1. B. firmus NA-1 was shown to be a glutamate-dependent strain for PGA production. The SSF of soybean grit was optimized in order to produce mucilage with a fortification of 5% glutamate, resulting in higher levels of mucilage production (6.14%) and a higher consistency index ($1.1\;Pa\;sec^n$). The sticky mucilage was comprised of 38% PGA, 7% levan, and some biopolymers. With regard to the viscoelastic properties of the mucilage solution, the viscous modulus (G") obtained from soybean grit fortified with 5% glutamate was approximately 64 times higher titan that of the mucilage solution obtained without glutamate. Although the addition of glutamate in the SSF of soybean grit influenced the rate of PGA production, the molecular weight of PGA remained unaltered, and was detected in a range between 1,400-1,440 kDa.

Effect of Cyclic Exposure on the Mechanical Properties of Fire Retardant Treated Plywood (순환적 폭로가 내화처리 합판의 기계적 성질에 미치는 영향)

  • Kim, Jong-Man;Levan, Susan L.
    • Journal of the Korean Wood Science and Technology
    • /
    • v.18 no.1
    • /
    • pp.31-38
    • /
    • 1990
  • 합판(合板)에 내화약제(耐火藥劑) 가압법(加壓法)에 의하여 약 1,588kg/$(30cm)^3$(3.5lbs/$ft^3$)을 주입시켜 내화합판(耐火合板)을 제조(製造)한 후(後), 이들 합판(合板)의 합수율(含水率)을 6%로 유지하면서, 기간은 0, 21, 60, 160 및 215일 동안 온도를 $26.6^{\circ}C(80^{\circ}F)$에 14 시간, $65^{\circ}C(150^{\circ}F)$에서 7시간, $26.6^{\circ}C$로 내리는데 1시간, $65^{\circ}C$로 올리는데 2시간씩으로 순환시켜, 내화처리합판(耐火處理合板)과 무처리합판(無處理合板)의 기계적 성질에 미치는 영향을 조사 비교 하였다. MOE는 내화처리합판(耐火處理合板)과 무처리합판(無處理合板) 사이에 유의성이 없었고, MOR에 있어서 내화처리합판(耐火處理合板)은 무처리합판(無處理合板)에 비하여 15~20% 감소하였고, WML에 있어서 내화처리합판(耐火處理合板)과 무처리합판(無處理合板)사이에 유의성이 있었으며, 두 내화처리합판(耐火處理合板) 사이에도 시간에 따라 유의성이 인정되었다. 따라서 WML은 내화처리합판(耐火處理合板)의 기계적 성질을 구명하는데 좋은 기준이 될 것으로 사료된다.

  • PDF

Purification and Characterization of Carboxymethyl-cellulase Produced by Bacillus sp. KD1014

  • Lee, Kyung-Dong;Kim, Jungho;Kim, Hoon
    • Journal of Applied Biological Chemistry
    • /
    • v.42 no.3
    • /
    • pp.107-112
    • /
    • 1999
  • A carboxymethyl-cellulase (CMCase) was purified from the culture supernatant of Bacillus sp. KD1014 by ultrafiltration, ammonium sulfate precipitation, and a series of chromatography on QAE-Sephadex A-50, hydroxylapatite and Sephadex G-75. The purified CMCase was a single protein of 32 kDa, showed an optimum activity at $60^{\circ}C$ and pH 6.0, and had a half-life of 23 min at $70^{\circ}C$. The enzyme activity was not influenced by metal ions such as $Mg^{2+},\;Fe^{3+},\;K^+,\;Zn^{2+}$, and $Cu^{2+}$ at a concentration of 1.0 mM, partially inhibited by $Mn^{2+}$ and $Ag^+$, and significantly inhibited by pentachlorophenol (PCP). The purified enzyme showed a 3.9-times higher activity on lichenan than on CMC, but hardly cleaved xylan, starch, avicel, laminarin, filter paper and levan. The results of activity staining of the purified enzyme separated by native and denaturing gel electrophoresis suggested that the CMCase might exist in dimeric, oligomeric or aggregated form as well as in monomeric form. The enzymatic cleavage products from cellotetraose indicated that the CMCase possessed transglycosylation activity.

  • PDF

Purification and Characterization Sucrose phosohorylase in Leuconostoc mesenteroides NRRL B-1149 (Leuconostoc mesenteroides NRRL B-1149의 Sucrose phosohorylase의 분리와 특성 연구)

  • Lee Jin Ha;Park Jun Seong;Park Hyen Joung;Cho Jae Young;Choi Jeong Sik;Kim Do Man
    • KSBB Journal
    • /
    • v.19 no.5
    • /
    • pp.363-367
    • /
    • 2004
  • Leuconostoc mesenteroides NRRL B-1149 produces various glucoseyltransferases for the synthesis of dextran, levan and glucose-1-phosphate using sucrose as a substrate. A sucrose phosphorylase (1149SPase) was purified from L. mesenteroides NRRL B-1149 culture by using hollow fiber filtration (30 kDa cut off), Toyopearl DEAE 650 M column chromatography and following two times of DEAE-Sepharose column chromatographies. The specific activity of the purified 1149SPase was 25.7 (U/mg) with $16\%$ yield. The 1149SPase showed a molecular size of 56 kDa on denatured $10\%$ SDS-PAGE. The N-terminal amino acid sequence of the enzyme was MEIQNKAM. The optimum pH and temperature of this enzyme were 6.2~6.5 and 37^{circ}C, respectively. It had an apparent K_{m} of 6.0 mM and K_{cat} of 1.62/s for sucrose. 1149SPase crystal was formed by hanging drop diffusion technique using 20 mM calcium chloride dihydrate, 100 mM sodium acetate trihydrate pH 4.6 and $30\%$ 2-methyl-2,4-pentanediol as vaporizing and reservation solution. The 1149SPase catalyzes transferring of glucose from isomaltose or sucrose to salicin and salicyl alcohol by disproportionation reaction or acceptor reaction and synthesized two acceptor products, respectively.