• Title/Summary/Keyword: hydrolytic

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Preparation of Hydrophobic Antimicrobal Compounds Encapsulated Nanoparticles Using Alkoxysilane-functionalized Amphiphilic Polymer Precursor and Their Antimicrobial Properties (실란 기능화 양친성 고분자 전구체를 이용한 소수성 항균물질 담지 나노 입자 제조 및 항균 특성)

  • Kim, Nahae;Kim, Juyoung
    • Journal of Adhesion and Interface
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    • v.18 no.1
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    • pp.13-24
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    • 2017
  • In this study, nanoparticles which encapsulated hydrophobic antimicrobial compounds with 50wt% of payload and 70%of solid content were prepared. These nanoparticles could be dispersed at water as well as various medium. Water dispersible organic-inorganic (O-I) hybrid nanoparticles were first prepared using alkoxysilane-functionalized amphiphilic polymer precursors through a conventional sol-gel process. Hydrophobic antimicrobial compound, Eugenol encapsulated nanoparticles were prepared using these O-I hybrid nanoparticles through a new nanoprecipitation process. The effect of various preparation on the size of nanoparticles, amount of payload, antimicrobial activity, and release rate of encapsulated compounds was investigated. All eugenol-encapsulated O-I nanoparticles regardless of preparation condition showed the same minimal inhibitory concentration (MIC) (50mg/ml) and 99% of antimicrobial activity for every strain. Their antimicrobial activity could maintain longer than two weeks. Especially, eugenol-encapsulated O-I nanoparticles prepared using tetraethoxysilane (TEOS) exhibited the highest payload (50wt%) and the lowest release rate which was owing to higher inorganic content in the O-I nanoparticles. And these O-I nanoparticles dispersed in hexanediol (HD) showed the highest antimicrobial activity and solid content (70wt%) because HD acted as a solvent as well as a antimicrobial agent.

In vivo Metabolism of Flupyrazofos into Plutella xylostella (Lepidoptera: Yponomeutidae) and Spodoptera exigua (Lepidoptera: Noctuidae) (배추좀나방과 파밤나방의 채내에서 Flupyrazofos의 대사)

  • Lee, Sang-Guei;Lee, Hoi-Seon;Hwang, Chang-Yeon;Han, Man-Jong;Park, Hyung-Man
    • The Korean Journal of Pesticide Science
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    • v.6 no.3
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    • pp.224-229
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    • 2002
  • In vivo metabolism study was carried out to find out the biochemical or metabolic tolerance mechanism between Diamond backmoth (DBM), Plutella xylostella and Beet armywarm (BAW), Spodoptera exigua to flupyrazofos. They showed some differences between the DBM and BAW. About 20% of flupyrazofos applied to the 3rd instar larvae of DBM was metabolized within 1 h and about 50% of that was metabolized within 4 h. The metabolites of flupyrazofos-oxon in 3rd instar larvae of DBM were increased 10 times more at 4 h than 1 h after application. The amounts of flupyrazol were nearly same between at 1 h and 4 h. The amount of unknown and origin increased 2 and 3 times more at 1 h than 4 h after application, respectively. In the 4th instar BAW larva, about 50% of flupyrazofos was metabolized within 1 h and about 70% of that was metabolized within 4 h. As metabolites, the amounts of flupyrazofos-oxon increased 2 times more at 4 h than 1 h after application. The amounts of flupyrazol increased 4 times more at 4 h than 1 h after application. The amount of unknown and origin increased 2.5 and 2 times more at 4 h than 1 h after application, respectively. From the study, it is supposed that hydrolytic enzyme, esterase, cleave the alkyl bond of flupyrazofos and conjugates with flupyrazofos. This seems to be the main tolerance mechanism of BAW to flupyrazofos.

Conformation and Reactivity of Herbicidal Benzenesulfonyl urea Compounds (제초성 Benzenesulfonyl urea계 화합물의 형태와 반응성)

  • Yu, Seong-Jae;Lee, Sang-Ho;Ko, Young-Kwan;Sung, Nak-Do
    • Applied Biological Chemistry
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    • v.39 no.3
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    • pp.235-240
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    • 1996
  • The most stable stereo conformer in non substituted benzenesulfonyl urea, 1 was the II-keto form, which the molecule was intramolecular associated(H-bond) coformer between imide group and N atom on the Pyrimidine ring. The hydrolytic degradation of 2 derivatives were proceeds by nucleophilic addition reaction(p<0) with orbital controlled intermolecular interaction between LUMO with electron donating$(\sigma<0)$ groups of 2 and HOMO of water molecule. N-(4,6-disub. pyrimid ine-2-yl)aminocarbonyl-2-(1,1-dimethoxy-2-fluoro)ethylbenze nesulfonamides,3 and N-(4,6-disub. triazine-2-yl)aminocarbonyl-2-(1,1-d imethoxy-2-fluoro)ethylbenzenesulfonamides,4 we re synthesized and their herbicidal activities in vivo against bulrush (Scirpus juncoides.) were measured by the pot test under the paddy conditions And the structure activity relationships(SAR) were analyzed by the multiple regression technique. The results of the SAR suggested that the 3 and 4 derivatives indicated dependent on the hydrophobicity of the 4,6-disubstituents and the heterocyclo group, where the optimal value $((log\;P)_{opt.}=0.89)$ of hydrophobicity was 0.89. The pyrimidine substituents, 3 showed higher herbicidal activity than the triazine substituents, 4. Among them, 4,6-dimethoxypyrimidine substituent, 3a showed the best herbicidal activity.

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On the Decomposition of Dimethyl-2, 2-dichlorovinylphosphate (Dimethyl-2, 2-dichlorovinylphosphate의 분해반응에 관한 연구)

  • Sung, Nack-Do;Park, Seung-Heui
    • Applied Biological Chemistry
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    • v.26 no.2
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    • pp.125-131
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    • 1983
  • Formal net charges, bond populations, atomic orbital coefficients, energy components and conformation of dimethyl-2,2-dichlorovinylphosphate have been studied theoretically by using the CNDO/2 molecular orbital calculation method in attempt to describe the reactivity and the stability of the molecule. From the analysis of rate equation, molecular orbital calculations and identification of the hydrolysis products, 2,2-dichloroacetaldehyde and dimethylphosphoric acid, a mechanism of the hydrolysis of dimethyl-2,2-dichlorovinylphosphate(DDVP) has been proposed. The hydrolysis of DDVP proceeds through the mechanism of nucleophilic addition, typical Micheal reaction in basic media. Therefore, it appears probable that the attack by strong nucleophile, hydroxide ion occurs at the increased positive charge $C_2({\alpha})$ atom of a staggered conformation due to the inductive effect (-)I>(+)R of 2,2-dichlorovinyl, electron-attracting group. And then, the hydrolytic scission involves the $C_2({\alpha})-O_3$, ${\pi}-anti-bonding\;orbital({\pi}^*)$ in the subsequent reaction in aqueous solution.

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Organic-inorganic Nanocomposite Adhesive with Improved Barrier Property to Water Vapor for Backsheets of Photovoltaic Modules (태양광모듈용 저가형 백시트 제조를 위한 고수분차단성 유무기 나노복합형 접착제)

  • Hwang, Jin Pyo;Lee, Chang Hyun
    • Membrane Journal
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    • v.25 no.6
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    • pp.530-537
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    • 2015
  • Photovoltaic (PV) modules are environmentally energy conversion devices to generate electricity via photovoltaic effect of semiconductors from solar energy. One of key elements in PV modules is "Backsheet," a multilayered barrier film, which determines their lifetime and energy conversion efficiency. The representative Backsheet is composed of chemically resistant poly(vinyl fluoride) (PVF) and cheap poly(ethylene terephthalate) (PET) films used as core and skin materials, respectively. PVF film is too expensive to satisfy the market requirements to Backsheet materials with production cost as low as possible. The promising alternatives to PVF-based Backsheet are hydrocarbon Backsheets employing semi-crystalline PET films instead of PVF film. It is, however, necessary to provide improved barrier property to water vapor to the PET films, since PET films are suffering from hydrolytic decomposition. In this study, a polyurethane adhesive with reduced water vapor permeation behavior is developed via a homogeneous distribution of hydrophobic silica nanoparticles. The modified adhesive is expected to retard the hydrolysis of PET films located in the core and inner skin. To clarify the efficacy of the proposed concept, the mechanical properties and electrochemical PV performances of the Backsheet are compared with those of a Backsheet employing the polyurethane adhesive without the silica nanoparticles, after the exposure under standard temperature and humidity conditions.

Isolation and Characteristics of Bacteria Showing Biocontrol and Biofertilizing Activities (생물방제 및 생물비료 활성을 가지는 세균의 분리 및 특성)

  • Jung, Ho-Il;Kim, Keun-Ki;Park, Hyean-Cheal;Lee, Sang-Mong;Kim, Yong-Gyun;Kim, Hong-Sung;Lee, Cnung-Yeol;Son, Hong-Joo
    • Journal of Life Science
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    • v.17 no.12
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    • pp.1682-1688
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    • 2007
  • To develop multifunctional microbial inoculant, microorganisms with antagonistic activity and biofertilizing activity were screened. Pantoea agglomerans and Bacillus megaterium from our laboratory culture collection, and strain MF12 from soil near poultry farm in Miryang were selected. On the basis of morphological, physiological studies and 16S rDNA sequence analysis, isolate MF12 was identified as the Bacillus pumilis. Three strains were studied for insoluble phosphate solubilization, indole-3-acetic acid (IAA) and siderophore production, ammonification ability, hydrolytic enzyme production and antifungal activity against phytopathogenic fungi. P. agglomerans did not produce any visible clear zone on agar plate containing 0.5% $Ca_3(PO_4){_2}$ as a sole phosphorus source. However, this strain could solubilize insoluble phosphate in liquid medium. All strains produced IAA ranged from $3{\sim}639{\mu}g/ml$ depending on culture time and had ammonification ability. Among three strains, only P. agglomerans produced siderophore. P. agglomerans produced pectinase and lipase, B. megaterium produced amylase, protease and lipase while B. pumilis produced protease and lipase. P. agglomerans showed antifungal activities against phytopathogenic fungi, Fusarium oxysporum and Colletotrichum gloeosporioides. B. pumilis showed antifungal activities against Botrytis cinerea, Sclerotinia sclerotiorum and Phythium ultimum.

Identification of Alga-lytic Bacterium AK-07 and Its Enzyme Activities Associated with Degradability of Cyanobacterium Anabaena cylindrica (Anabaena cylindrica 분해세균 AK-07의 동정과 분해 관련 효소활성 조사)

  • Kim, Jeong-Dong;Han, Myung-Soo
    • Korean Journal of Ecology and Environment
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    • v.36 no.2 s.103
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    • pp.108-116
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    • 2003
  • To investigate bacteria with algal Iytic activities against Anabaena cylindrica when water blooming occurs and to study enzyme profiles of alga-Iytic bacteria, various bacterial strains were isolated from surface waters and sediments in eutrophic lakes or reservoirs in Korea. Abacterial strain AK-07 was characterized and identified as Acinetobacter johnsonii based on its16S rDNA base sequence. When AK-07 was co-cultivated with A. cylindrica, bacterial cells propagated to $8\;{\times}\;10^8$ cfu $ml^{-1}$ and Iyses algal cells. However, culture filtrates of AK-07 did not exhibit algal Iytic activities. That suggesting the enzymes on the surfaces of the bacterium might be effective algal Iytic agents to cause Iyses of cells. Acinetobacter johnsonii AK-07 exhibited high degradation activities against A. cylindrica, and formed alginase, caseinase, lipase, fucodian hydrolase, and laminarinase. Moreover, glycosidases for example ${\beta}$-galatosidase, ${\beta}$-glucosidase, ${\beta}$-glucosaminidase, and ${\beta}$-xylosidase, which hydrolyzed ${\beta}$-0-glycosidic bonds, were found in cell-free extracts of A. johnsonii AK-07. Other glycosidase such as ${\alpha}$-galctosidases, ${\alpha}$-N-Ac-galctosidases, ${\alpha}$-mannosidases, and ${\alpha}$- L-fuco-sidases, which cleavage ${\alpha}$-0-glycosidic bondsare not detected. In the results, enzyme systemsof A. johnsonii AK-07 were very complex to do-grade cell walls of cyanobacteria. The polysaccharides or peptidoglycans of A. cylindrica maybe hydrolyzed and metabolized to a range of easily utilizable monosaccharides or other low molecular weight organic substances by strain AK-07 of A. johnsonii.

Characterization of Potential Plant Growth-promoting Rhizobacteria as Biological Agents with Antifungal Activity, Plant Growth-promoting Activity, and Mineral Solubilizing Activity (항진균 활성, 식물 생장촉진 활성, 미네랄 가용화능을 가진 생물학적 제제로서 잠재적 식물 생장촉진 근권세균의 특성조사)

  • Lee, Song Min;Kim, Ji-Youn;Kim, Hee Sook;Oh, Ka-Yoon;Lee, Kwang Hui;Lee, Sang-Hyeon;Jang, Jeong Su
    • Journal of Life Science
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    • v.31 no.7
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    • pp.641-653
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    • 2021
  • The purpose of this study was to confirm the antifungal activity, plant growth-promoting activity, and mineral solubilizing activity of 18 types of bacteria isolated purely from rhizosphere soil. The potential of isolates of the genus Bacillus and Pseudomonas as biocontrol agents was confirmed through the antifungal activity of these isolates. This activity has been determined to be due to various hydrolytic enzymes on the cell wall of plant pathogenic fungi and the production of siderophores in isolates. In addition, most of the isolates have been found to have aminocyclopropane-1-carboxylate deaminase production activity, indole-3-acetic acid production activity, and nitrogen fixation activity. These characteristics are believed to have a positive effect on root development, growth, and the productivity of crops via a reduction in the concentration of ethylene under conditions of environmental stress, to which plants are commonly exposed. In addition, on testing for the solubilizing activity of the isolates for phosphoric acid, silicon, calcium carbonate, and zinc, some isolates were found to have mineral solubilizing activities. Inoculation of these isolates during plant growth is expected to assist plant growth by converting nutrients necessary for growth into usable forms that can be absorbed by plants. The 18 isolated strains can be used as biocontrol agents due to their antifungal activity, plant growthpromoting activity, and mineral solubilizing activity.

Enhanced Tolerance of Chinese Cabbage Seedlings Mediated by Bacillus aryabhattai H26-2 and B. siamensis H30-3 against High Temperature Stress and Fungal Infections

  • Lee, Young Hee;Jang, Su Jeong;Han, Joon-Hee;Bae, Jin Su;Shin, Hyunsuk;Park, Hee Jin;Sang, Mee Kyung;Han, Song Hee;Kim, Kyoung Su;Han, Sang-Wook;Hong, Jeum Kyu
    • The Plant Pathology Journal
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    • v.34 no.6
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    • pp.555-566
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    • 2018
  • Two rhizobacteria Bacillus aryabhattai H26-2 and B. siamensis H30-3 were evaluated whether they are involved in stress tolerance against drought and high temperature as well as fungal infections in Chinese cabbage plants. Chinese cabbage seedlings cv. Ryeokgwang (spring cultivar) has shown better growth compared to cv. Buram-3-ho (autumn cultivar) under high temperature conditions in a greenhouse, whilst there was no difference in drought stress tolerance of the two cultivars. In vitro growth of B. aryabhattai H26-2 and B. siamensis H30-3 were differentially regulated under PEG 6000-induced drought stress at different growing temperatures (30, 40 and $50^{\circ}C$). Pretreatment with B. aryabhattai H26-2 and B. siamensis H30-3 enhanced the tolerance of Chinese cabbage seedlings to high temperature, but not to drought stress. It turns out that only B. siamensis H30-3 showed in vitro antifungal activities and in planta crop protection against two fungal pathogens Alternaria brassicicola and Colletotrichum higginsianum causing black spots and anthracnose on Chinese cabbage plants cv. Ryeokgwang, respectively. B. siamensis H30-3 brings several genes involved in production of cyclic lipopeptides in its genome and secreted hydrolytic enzymes like chitinase, protease and cellulase. B. siamensis H30-3 was found to produce siderophore, a high affinity iron-chelating compound. Expressions of BrChi1 and BrGST1 genes were up-regulated in Chinese cabbage leaves by B. siamensis H30-3. These findings suggest that integration of B. aryabhattai H26-2 and B. siamensis H30-3 in Chinese cabbage production system may increase productivity through improved plant growth under high temperature and crop protection against fungal pathogens.

Effect of amaranth seed extracts on glycemic control in HepG2 cells (HepG2 세포에서 아마란스 종자 에탄올 추출물이 포도당 흡수 조절에 미치는 효과)

  • Park, So Jin;Park, Jong Kun;Hwang, Eunhee
    • Journal of Nutrition and Health
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    • v.54 no.6
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    • pp.603-617
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    • 2021
  • Purpose: This study was carried out to investigate the effect of amaranth seed extracts on glycemic regulation in HepG2 cells. The 80% ethanol extracts of amaranth seeds were used to evaluate α-amylase and α-glucosidase activities, cell viability, glucose uptake and messenger RNA (mRNA) expression levels of acetyl-CoA carboxylase (ACC), glucose transporter (GLUT)-2, GLUT-4, insulin receptor substrate (IRS)-1 and IRS-2. Methods: The samples were prepared and divided into 4 groups, including germinated black amaranth (GBA), black amaranth (BA), germinated yellow amaranth (GYA) and yellow amaranth (YA). Glucose hydrolytic enzyme, α-amylase and α-glucosidase activities were examined using a proper protocol. In addition, cell viability was measured by MTT assay. Glucose uptake in cells was measured using an assay kit. The mRNA expression levels of ACC, GLUT-2, GLUT-4, IRS-1 and IRS-2 were measured by reverse transcription polymerase chain reaction. Results: The inhibitory activities of α-amylase and α-glucosidase were highly observed in GBA, followed by BA, GYA and YA. Similar results were observed for glucose. The GBA effect was similar compared to the positive control group. The mRNA expression levels of ACC, GLUT-2, GLUT-4, IRS-1, and IRS-2 were significantly increased. The potential hypoglycemic effects of amaranth seed extracts were observed due to the increase in glucose metabolic enzyme activity, and glucose uptake was mediated through the upregulation of ACC, GLUT-2, GLUT-4, IRS-1, and IRS-2 expression levels. Conclusion: Our findings suggest that the amaranth seed is a potential candidate to prevent a diabetes. The present study demonstrated the possibility of using amaranth seeds, especially GBA and BA for glycemic control.