• Title/Summary/Keyword: Km value

Search Result 892, Processing Time 0.027 seconds

Analysis of Catalases from Photosynthetic Bacterium Rhodospirillum rubrum Sl

  • Lim, Hee-Kyung;Kim, Young-Mi;Lee, Dong-Heon;Kahng, Hyung-Yeel;Oh, Duck-Chul
    • Journal of Microbiology
    • /
    • v.39 no.3
    • /
    • pp.168-176
    • /
    • 2001
  • Five different types of catalases from photosynthetic bacterium Rhodospirillum rubrum S1 grown aerobically in the dark were found in this study, and designated Catl (350 kDa), Cat2 (323 kDa), Cat3 (266 kDa), Cat4 (246 kDa), and Cat5 (238 kDa). Analysis of native PAGE revealed that Cat2, Cat3, and Cat4 were also produced in the cells anaerobically grown in the light. It is notable that only Cat2 was expressed much more strongly in response to the anaerobic condition. Enzyme activity staining demonstrated that Cat3 and Cat4 had bifunctional catalase-peroxidase activities, while Catl, Cat2, and Cat5 were typical monofunctional catalases. S1 cells grown aerobically in the presence of malate as the sole source of carbon exhibited an apparent catalase Km value of 10 mM and a Vmax of about 705 U/mg protein at late stationary growth phase. The catalase activity of Sl cells grown in the anaerobic environment exhibited a much lower Vmax of about 109 U/mg protein at late logarithmic growth phase. The catalytic activity was stable in the broad range of temperatures (30$\^{C}$-60$\^{C}$), and pH (6.0-10.0). R. rubrum S1 was much more resistant to H$_2$O$_2$in the stationary growth phase than in the exponential growth phase regardless of growth conditions. Cells of stationary growth phase treated with 15 mM H$_2$O$_2$for 1 h showed 3-fold higher catalase activities than the untreated cells. In addition, L-glutamate induced an 80-fold increase in total catalase activity of R. rubrum S1 compared with magic acid. Through fraction analyses of S1 cells, Cat2, Cat3, Cat4 and Cat5 were found in both cytoplasm and periplasm, while Catl was localized only in the cytoplasm.

  • PDF

The Influence of Flip-flops Gait on the Muscle Activity of Tibilalis anterior and Gastrocnemius

  • Choi, Jung Hyun;Song, Mi Ri;Lee, Joong Hyun;Kim, Hong Rae;Park, Si Eun;Kim, Ji Sung;Kwak, Dae Young;Lee, Sang Bin;Kim, Nyeon Jun;Koo, Ja Pung;Kim, Soon Hee
    • Journal of International Academy of Physical Therapy Research
    • /
    • v.4 no.2
    • /
    • pp.562-565
    • /
    • 2013
  • The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.

Antioxidative Effects of Extracts of Various Cultivars and Different Plant Parts of Eggplant (가지의 품종별, 부위별 추출물의 항산화 효과)

  • Beik, Kyung-Yean;Lee, Sang-Il;Kim, Jeong-Sook;Lee, Doo-Young;Oh, Seoung-Hee;Kim, Soon-Dong
    • Journal of the East Asian Society of Dietary Life
    • /
    • v.19 no.2
    • /
    • pp.195-201
    • /
    • 2009
  • The antioxidative activities of two varieties of egg plant (Chunyang No 2: Dangaji, Jinju Janggaji: Janggaji) extracts were investigated. The total polyphenol contents of Dangaji peel hot water extract and the Janggaji flesh and fruit hot water extracts were higher than those of the other samples. However, the DPPH radical scavenging activities(electron donating activity) of Dangaji flesh-ethanol, peel-cold water, and fruit- ethanol extracts, as well as the Janggaji peel cold water extract, were higher than those of the other samples. Furthermore, the in vitro inhibitory effects of the Dangaji peel cold water and hot water extracts on rat hepatic xanthine oxidase were highest among the samples, and were exhibited in a dose dependant manners. Although there were marked changes in the xanthine oxidase Km values for xanthine as a substrate, the Vmax value changes by the addition of the Dangaji water extracts were minor compared with the control. This result suggests that Dangaji water extracts may regulate the activity of xanthine oxidase-via the inhibition of binding affinity between the enzyme and substrate. The present study provides experimental evidence that constituents of egg plant extracts may ameliorate reactive oxygen species(ROS)-induced oxidative stress via hepatic hepatic xanthine oxidase activity, but further studies to identify the active antioxidants and compounds and inhibitors of xanthine oxidase are required.

  • PDF

Evaluation of Wind Turbine Efficiency of Haengwon Wind Farm in Jeju Island based on Korean Wind Map (풍력-기상자원지도에 기반한 제주 행원 풍력발전단지 효율성 평가)

  • Byon, Jae-Young;Kang, Mi-Sun;Jung, Hyun-Sook
    • Journal of the Korean earth science society
    • /
    • v.34 no.7
    • /
    • pp.633-644
    • /
    • 2013
  • This study evaluates wind farm efficiency at Haengwon in Jeju Island. The actual energy production at Haengwon wind farm is compared with the estimated energy production based on Korean wind map which is developed at the National Institute of Meteorological Research/KMA. The validation of wind map at Gujwa located near the Haengwon wind farm shows that the wind speed is overestimated. The diurnal variation of wind speed shows a maximum value in the afternoon due to the effect of sea-land breeze. The ratio of the actual energy production at Haengwon wind farm and the estimated energy production based on the Korean wind map is 24.8%, while the distribution of energy frequency is similar each other. The difference of energy production is caused by mechanical error of the turbine and the overestimation of the simulated wind map. This study will contribute to the repowering of turbines for improving the efficiency of wind farm in the future.

Validation of an Anthracnose Forecaster to Schedule Fungicide Spraying for Pepper

  • Ahn, Mun-Il;Kang, Wee-Soo;Park, Eun-Woo;Yun, Sung-Chul
    • The Plant Pathology Journal
    • /
    • v.24 no.1
    • /
    • pp.46-51
    • /
    • 2008
  • With the goal of achieving better integrated pest management for hot pepper, a disease-forecasting system was compared to a conventional disease-control method. Experimental field plots were established at Asan, Chungnam, in 2005 to 2006, and hourly temperature and leaf wetness were measured and used as model inputs. One treatment group received applications of a protective fungicide, dithianon, every 7 days, whereas another received a curative fungicide, dimethomorph, when the model-determined infection risk (IR) exceeded a value of 3. In the unsprayed plot, fruits showed 18.9% (2005) and 14.0% (2006) anthracnose infection. Fruits sprayed with dithianon at 7-day intervals had 4.7% (2005) and 15.4% (2006) infection. The receiving model-advised sprays of dimethomorph had 9.4% (2005) and 10.9% (2006) anthracnose infection. Differences in the anthracnose levels between the conventional and model-advised treatments were not statistically significant. The efficacy of 10 (2005) and 8 (2006) applications of calendar-based sprays was same as that of three (2005 and 2006) sprays based on the disease-forecast system. In addition, we found much higher the IRs with the leaf wetness sensor from the field plots comparing without leaf wetness sensor from the weather station at Asan within 10km away. Since the wetness-periods were critical to forecast anthracnose in the model, the measurement of wetness-period in commercial fields must be refined to improve the anthracnose-forecast model.

Studies on Gibberellic Acid-promoted and Indole-3-acetic Acid-repressed Amylase Synthesis of Barley Seeds (대맥종자의 Amylase 생성에 미치는 Gibberellic Acid의 촉진효과와 Indole-3-acetic Acid의 억제효과의 해석)

  • 채인기
    • Journal of Plant Biology
    • /
    • v.20 no.2
    • /
    • pp.91-101
    • /
    • 1977
  • Using barley seeds (Hordeum sativum Jess, var.), the influences of gibberellic acid (GA) and indole-3-acetic acid(IAA) on the amylase synthesis and that of the nucleic acid metabolism were investigated. 1. With the deembrynized barley seeds, the increase of amylase treated with a $10^{-5}M$ of GA and the decrease of amylase treated with $10^{-5}M$IAA were matched by a proportionate increase and decrease in the amount of RNA. The influence of the hormones on the RNA synthesis has appeared immediately after the treatment but on the amylase synthesis it has appeared 8 hours later. But no influence on the DNA synthesis was observed on both hormones. 2. The amylase from deembryonized barley seeds treated with GA and IAA have been fractionated by gel filteration on Sephadex G-100. The amylase components showed four fractions on both enzymes treated with GA and IAA. Fraction I(FI) was differed from fraction Ⅵ(FIV) in Km value and the effects of temperature, pH and metal ions. On the basis of their emzymatic properties, it was considered that the FI was $\beta$-amylase and FIV was $\alpha$-amylase. The influences of GA and IAA on each fractions appeared to be similar but on the amylase units per souble protein, IAA inhibited the production of amylase FIV while it promoted that of amylase FI. 3. An experiment was conducted to determine whether IAA inhibits GA-promoted amylase synthesis competitively or non-competitively. Using a Lineweaver-Burk plot, it was clear that IAA was acting in a non-competitive fashion. From this, IAA was probably not competing with GA at the same site, but it was acting at some other site which resutled in partial blocking of the action of GA on the amylase synthesis.

  • PDF

Molecular characterization and expression of cytosolic OASTL control cysteine metabolism in Mimosa pudica L.

  • Harun-Ur-Rashid, Md.;Masakazu, Fukuta;Hossain, Md. Amzad;Oku, Hirosuke;Iwasaki, Hironori;Oogai, Shigeki;Anai, Toyoaki
    • Proceedings of the Korean Society of Crop Science Conference
    • /
    • 2017.06a
    • /
    • pp.224-224
    • /
    • 2017
  • In plants, cysteine(Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur containing secondary products. Cys formation is involved in the consecutive two reactions using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast and mitochondria. OASTL is able to produce mimosine with 3-hydroxy-4-pyridone (3H4P) in lieu of $H_2S$ for Cys. In this report, we describe the first time cloning, purification and characterization of cytosolic(cy)OASTL from M. pudica and its expression in Escherichia coli and try to find out the cross link between this OASTL and the mimosine formation and to elucidate the metabolic role of cy-OASTL in M. pudica. The purified recombinant protein was 34.7 KDa. The optimum reaction pH and temperature was 6.5 and $50^{\circ}C$, respectively. The Michaelis constant (Km) and the Vmax value of the enzyme was $252{\pm}25{\mu}M$ and $57{\pm}3{\mu}M\;cysteine\;min^{-1}\;{\mu}g\;protein^{-1}$ for sulfide and $159{\pm}21{\mu}M$ and $58{\pm}2.4{\mu}M\;cysteine\;min^{-1}\;{\mu}g\;protein^{-1}$ for OAS subsequently. After cleaving the His-tag, we tried to observe cy-OASTL to form mimosine with appropriate substrate but it was not successful. It may be concluded that cy-OASTL of the present study is only Cys specific, not mimosine.

  • PDF

Dependence of Barredness of Late-Type Galaxies on Galaxy Properties and Environment

  • Lee, Gwang-Ho;Park, Chang-Bom;Lee, Myung-Gyoon;Choi, Yun-Young
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.35 no.1
    • /
    • pp.75.2-75.2
    • /
    • 2010
  • We investigate the dependence of occurrence of bar in galaxies on galaxy properties and environment. The environmental conditions considered include the large-scale background density and distance to the nearest neighbor galaxy. We use a volume-limited sample of 33,296 galaxies brighter than $M_r$=-19.5+5logh at $0.02{\leqq}z{\leqq}0.05489$, drawn from the Sloan Digital Sky Survey Data Release 7. We classify the galaxies into early and late types, and identify bars by visual inspection. We find that the fraction of barred galaxies ($f_{bar}$) is 18.2% on average in the case of late-type galaxies, and depends on both u-r color and central velocity dispersion $(\sigma);f_{bar}$ is a monotonically increasing function of u-r color, and has a maximum value at intermediate velocity dispersion (${\sigma}{\simeq}170km\;s^{-1}$). This trend suggests that bars are dominantly hosted by systems having intermediate-mass with no recent interaction or merger history. We also find that $f_{bar}$ does not directly depend on the large-scale background density as its dependence disappears when other physical parameters are fixed. We discover the bar fraction decreases as the separation to the nearest neighbor galaxy becomes smaller than 0.1 times the virial radius of the neighbor regardless of neighbor's morphology. These results imply that it is difficult for bars to be maintained during strong tidal interactions, and that the source for this phenomenon is gravitational and not hydrodynamical.

  • PDF

Development of Knee Ankle Foot Orthosis for Gait Rehabilitation Training using Plantaflexion and Knee Extension Torque (족저굴곡과 무릎 신전 토크를 이용한 보행 재활 훈련용 장하지 보조기 개발)

  • Kim, Kyung;Kim, Jae-Jun;Heo, Min;Jeong, Gu-Young;Ko, Myoung-Hwan;Kwon, Tae-Kyu
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.16 no.10
    • /
    • pp.948-956
    • /
    • 2010
  • The purpose of this study was to test the effectiveness of a prototype KAFO (Knee-Ankle-Foot Orthosis) powered by two artificial pneumatic muscles during walking. We had previously built powered AFO (Ankle-Foot Orthosis) and KO (Knee Orthosis) and used it effectively in studies on assistance of plantaflexion and knee extension motion. Extending the previous study to a KAFO presented additional challenges related to the assistance of gait motion for rehabilitation training. Five healthy males were performed gait motion on treadmill wearing KAFO equipped with artificial pneumatic muscles to power ankle plantaflexion and knee extension. Subjects walked on treadmill at 1.5 km/h under four conditions without extensive practice: 1) without wearing KAFO, 2) wearing KAFO with artificial muscles turned off, 3) wearing KAFO powered only in plantaflexion under feedforward control, and 4) wearing KAFO powered both in plantaflexion and knee extension under feedforward control. We collected surface electromyography, foot pressure and kinematics of ankle and knee joint. The experimental result showed that a muscular strength of wearing KAFO powered plnatarfexion and knee extension under feedforward control was measured to be lower due to pneumatic assistance and foot pressure of wearing KAFO powered plnatarfexion and knee extension under feedforward control was measured to be greater due to power assistance. In the result of motion analysis, the ankle angle of powered KAFO in terminal stance phase was found a peak value toward plantaflexion and there were difference of maximum knee flexion range among condition 2, 3 and 4 in mid-swing phase. The current orthosis design provided plantaflexion torque of ankle jonit in terminal stance phase and knee extension torque of knee joint in mid-swing phase.

Expansion of an invasive species, Ailanthus altissima, at a regional scale in Japan

  • Chuman, Misaki;Kurokochi, Hiroyuki;Saito, Yoko;Ide, Yuji
    • Journal of Ecology and Environment
    • /
    • v.38 no.1
    • /
    • pp.47-56
    • /
    • 2015
  • Ailanthus altissima, which is recognized as an invasive tree in the Western world, has been widely observed in Japan. To investigate how A. altissima expanded within-population and to new populations within a region, 446 A. altissima trees were sampled from three separate sites (A, B, and C) including 35 distantly positioned patches, with three chloroplast DNA markers and nine nuclear microsatellite markers. We detected 2, 2, and 3 chloroplast haplotypes in sites A, B, and C, respectively. In addition, 271, 40, and 41 nuclear genotypes were detected in sites A, B, and C, respectively. The clonal richness value was 0.85, 0.78, and 0.53 in sites A, B, and C, respectively. Most trees with the same genotypes were distributed in the same patch, indicating that range expansion by asexual reproduction was limited to a maximum of 45 meters. According to autocorrelation analysis, the extent of nonrandom spatial genetic structure was approximately 0-2 km in sites A and C. KINGROUP analyses showed that 812, 74, and 111 nuclear genotype pairs were detected to have kinship in sites A, B, and C, respectively. Most nuclear genotype pairs were detected within the same patches or sites. These results indicate that the number of A. altissima trees gradually increased from seeds, some of which were produced by trees within sites, meaning that this species could regenerate naturally. This shows the need for the future management of A. altissima as an invasive species in Japan.