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Insecticidal activity of Ruta chalepensis leaf-derived component against Sitophilus zeamais
Ju-Hyun Jeon,Geon-Hwi Lee,Sang-Guei Lee,Hoi-Seon Lee 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05
Insecticidal activity of active component isolated from Ruta chalepensis leaves was examined against maize weevil, Sitophilus zeamais and compared with two different bioassay system, such as direct contact and fumigant method. The methanol extract of R. chalepensis leaves had strongly (+++) insecticidal activity at 50 mg/disk against S. zeamais. Methanol extract of R. chalepensis was partitioned with hexane, chloroform, ethyl acetate, butanol and water fraction, successively. In this result, the highest activity was shown in chloroform fraction against S. zeamais. Biologically active compound derived from chloroform fraction of R. chalepensis extract was purified by using SiO2 column chromatography and prep-HPLC. The insecticidal constituent of R. chalepensis was identified as quinoline-4-carboxaldehyde by various chromatography and spectroscopic analysis methods. At 2.5 mg/disk, the most toxic activity against S. zeamais was exerted by the direct contact method (100%), followed by the fumigant method (23%). These results revealed that the contact toxicity showed 4.35 times greater than the respiration toxicity. Furthermore, these results indicate that quinoline- 4-carboxaldehyde could be useful as a new preventive agent against damage caused by stored-product insects.
Behavioral Responses of Small Size Insects to High Power Light Emitting Diodes
Hoi-Seon Lee 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10
The object of this study is to observe the attraction of specific wavelengths against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). The attractive effects was examined by the high power light-emitting diodes (HPLEDs) in the dark room at 27±0.5°C and 60±0.5% relative humidity. Evaluated specific wavelengths were blue (470±10 nm), green (520±5 nm), yellow (590±5 nm) and red (625±10 nm) HPLEDs. When a light exposure time was fixed at 60 min and tested with various illuminance intensity at 20, 40, 60, 80, and 100 lux, the attraction rate of the green HPLED at 80 lux was the most effective (94.4%) to B. tabaci, followed by yellow HPLED of 20 lux (78.9%), blue HPLED of 60 lux (71.1%), and red HPLED of 20 lux (60.0%), respectively. According to the change of light exposure time (10, 20, 30, 40, 50, and 60 min), green HPLED showed the potential attractive effects under the 40 min and 50 min. These results suggest that it is possible to develop a green HPLED trap for attracting, monitoring, and lighting system against B. tabaci.
Why do Chickpea ( Cicer arietinum L. ev. Tyson ) Bacteroids Contain Little Poly-β-Hydroxybutyrate?
(Hoi Seon Lee) 한국응용생명화학회 1999 Applied Biological Chemistry (Appl Biol Chem) Vol.42 No.1
Poly-β-hydroxybutyrate (PHB) and enzymes related PHB metabolism have been measured in nitrogen-fixing symbiosis of chickpea and cowpea plants. Bacteroids from chickpea and cowpea contained PHB to 0.8% and 43% of their dry weight, respectively, whereas the free-living cells CC 1192 and I 16 produced 285±55 mg and 157±18 mg of PHB g (dry weight)^(-1). To further understand why chickpea bacteroids contained little PHB, the enzyme activities of PHB metabolism (3-ketothiolase, acetoacetyl-CoA reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the TCA cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and cowpea bacteroids and the respective free-living bacteria. Significant differences were observed between chickpea and cowpea bacteroids and between the bacteroid and free-living forms of CC 1192, with respect to the capacity for some of these reactions. It is indicated that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids could be a factor that favors the utilization of acetyl-CoA in TCA cycle rather than for PHB synthesis.
(Hoi Seon Lee) 한국응용생명화학회 1999 Applied Biological Chemistry (Appl Biol Chem) Vol.42 No.1
Sucrose synthase (EC 2.4.1.13) has been purified from the plant cytosolic fraction of chickpea (Cicer arietinum L. cv. Amethyst) nodules. The native enzyme had a molecular mass of 356±15 kD. The subunit molecular mass was 87±2 kD, and a tetrameric structure is proposed for sucrose synthase of chickpea nodule. Optimum activities in the sucrose cleavage and synthesis directions were at pH 6.5 and 9.0, respectively. The purified enzyme displayed typical hyperbolic kinetics with substrates in cleavage and synthesis reactions. Chickpea nodules sucrose synthase had a high affinity for UDP (K_m, 8.0 μM) and relatively low affinities for ADP (K_m, 0.23 mM), CDP (K_m, 0.87 mM), and GDP (K_m, 1.51 mM). The K_m for sucrose was 29.4 mM. In the synthesis reaction, UDP-glucose (K_m, 24.1 μM) was a more effective glucosyl donor than ADP-glucose (K_m, 2.7 mM), and the K_m for fructose was 5.4 mM. Divalent cations, such as Ca^(2+), Mg^(2+), and Mn^(2+), stimulated the enzyme activity in both the cleavage and synthesis directions, and the enzyme was very sensitive to inhibition by HgCl₂ and CuSO₄.
Hepatocyte-specific Prominin-1 protects against liver injury-induced fibrosis by stabilizing SMAD7
Lee Hyun,Yu Dong-Min,Bahn Myeong-Suk,Kwon Young-Jae,Um Min Jee,Yoon Seo Yeon,Kim Ki-Tae,Lee Myoung-Woo,Jo Sung-Je,Lee Sungsoo,Koo Seung-Hoi,Jung Ki Hoon,Lee Jae-Seon,Ko Young-Gyu 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
Prominin-1 (PROM1), also known as CD133, is expressed in hepatic progenitor cells (HPCs) and cholangiocytes of the fibrotic liver. In this study, we show that PROM1 is upregulated in the plasma membrane of fibrotic hepatocytes. Hepatocellular expression of PROM1 was also demonstrated in mice (Prom1CreER; R26TdTom) in which cells expressed TdTom under control of the Prom1 promoter. To understand the role of hepatocellular PROM1 in liver fibrosis, global and liver-specific Prom1-deficient mice were analyzed after bile duct ligation (BDL). BDL-induced liver fibrosis was aggravated with increased phosphorylation of SMAD2/3 and decreased levels of SMAD7 by global or liver-specific Prom1 deficiency but not by cholangiocyte-specific Prom1 deficiency. Indeed, PROM1 prevented SMURF2-induced SMAD7 ubiquitination and degradation by interfering with the molecular association of SMAD7 with SMURF2. We also demonstrated that hepatocyte-specific overexpression of SMAD7 ameliorated BDL-induced liver fibrosis in liver-specific Prom1-deficient mice. Thus, we conclude that PROM1 is necessary for the negative regulation of TGFβ signaling during liver fibrosis.