• Title, Summary, Keyword: inhibition

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Antiarteriosclerosis Effects of Black Rices Extract (흑미 추출물에 대한 항동맥경화 효과(Notes))

  • Lim, Chi-Hwan;Kim, Jong-Min;Baek, Seung-Hwa
    • Journal of Society of Preventive Korean Medicine
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    • v.12 no.3
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    • pp.91-98
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    • 2008
  • 80% MeOH extract of black rices fractionated with n-hexane, EtOAc, and n-BuOH. Copper-induced LDL oxidation inhibition assay and ACAT inhibition assay examined with fractions. n-Hexane and EtOAc fractions showed high inhibition activity. We divided n-hexane fraction into three sub-layers(H1 - H3) and EtOAc into eight sub-layers(E1 - E8). H1, H2, E6, and E7 are showed higher inhibition activity than standard in Lp-PLA2 inhibition assay and H1 and E6 are showed higher ACAT inhibition activity than standard.

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Phasic and Tonic Inhibition are Maintained Respectively by CaMKII and PKA in the Rat Visual Cortex

  • Joo, Kayoung;Yoon, Shin Hee;Rhie, Duck-Joo;Jang, Hyun-Jong
    • The Korean Journal of Physiology and Pharmacology
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    • v.18 no.6
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    • pp.517-524
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    • 2014
  • Phasic and tonic ${\gamma}$-aminobutyric acidA ($GABA_A$) receptor-mediated inhibition critically regulate neuronal information processing. As these two inhibitory modalities have distinctive features in their receptor composition, subcellular localization of receptors, and the timing of receptor activation, it has been thought that they might exert distinct roles, if not completely separable, in the regulation of neuronal function. Inhibition should be maintained and regulated depending on changes in network activity, since maintenance of excitation-inhibition balance is essential for proper functioning of the nervous system. In the present study, we investigated how phasic and tonic inhibition are maintained and regulated by different signaling cascades. Inhibitory postsynaptic currents were measured as either electrically evoked events or spontaneous events to investigate regulation of phasic inhibition in layer 2/3 pyramidal neurons of the rat visual cortex. Tonic inhibition was assessed as changes in holding currents by the application of the $GABA_A$ receptor blocker bicuculline. Basal tone of phasic inhibition was maintained by intracellular $Ca^{2+}$ and $Ca^{2+}$/calmodulin-dependent protein kinase II (CaMKII). However, maintenance of tonic inhibition relied on protein kinase A activity. Depolarization of membrane potential (5 min of 0 mV holding) potentiated phasic inhibition via $Ca^{2+}$ and CaMKII but tonic inhibition was not affected. Thus, phasic and tonic inhibition seem to be independently maintained and regulated by different signaling cascades in the same cell. These results suggest that neuromodulatory signals might differentially regulate phasic and tonic inhibition in response to changes in brain states.

Kinetic Evidence for the Interactive Inhibition of Laccase from Trametes versicolor by pH and Chloride

  • Raseda, Nasrin;Hong, Soonho;Kwon, O Yul;Ryu, Keungarp
    • Journal of Microbiology and Biotechnology
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    • v.24 no.12
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    • pp.1673-1678
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    • 2014
  • The interactive inhibitory effects of pH and chloride on the catalysis of laccase from Trametes versicolor were investigated by studying the alteration of inhibition characteristics of sodium chloride at different pHs for the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid). At pH 3.0, the addition of sodium chloride (50 mM) brought about a 40-fold increase in $K{_m}^{app}$ and a 4-fold decrease in $V_{max}{^{app}}$. As the pH increased to 7.0, the inhibitory effects of sodium chloride became significantly weakened. The mixed-inhibition mechanism was successfully used to quantitatively estimate the competitive and uncompetitive inhibition strengths by chloride at two different pHs (pH 3.0 and 6.0). At pH 3.0, the competitive inhibition constant, $K_i$, was 0.35 mM, whereas the uncompetitive inhibition constant, $K{_i}^{\prime}$, was 18.1 mM, indicating that the major cause of the laccase inhibition by chloride is due to the competitive inhibition step. At a higher pH of 6.0, where the inhibition of the laccase by hydroxide ions takes effect, the inhibition of the laccase by chloride diminished to a great extent, showing increased values of both the competitive inhibition constant ($K_i=23.7mM$) and uncompetitive inhibition constant ($K{_i}^{\prime}=324mM$). These kinetic results evidenced that the hydroxide anion and chloride share a common mechanism to inhibit the laccase activity.

Haldane Inhibition at CAH DNAPL Source Zone in Soil and Groundwater

  • Yu, Seung-Ho;Semprini, Lewis
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.33-36
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    • 2004
  • Two biokinetic models (\circled1 Mrichaelis-Menten kinetics with competitive inhibition \circled2 with both competitive inhibition and Haldane inhibition) for reductive dechlorination were developed and compared with results from batch kinetic tests conducted over a wide range of PCE and TCE concentrations with two different dechlorinating cultures. At PCE concentrations lower than 300 $\mu$M, both model simulated the experimental results well. However, The kinetic model that incorporated both competitive and Haldane inhibitions much better simulated experimental data for PCE concentrations greater than 300-400 $\mu$M, and TCE concentrations at half its solubility limit (4000 $\mu$M). The PM culture showed Haldane inhibition constants of 900, 6000, 7000 $\mu$M for TCE, c-DCE and VC, indicating very weak Haldane inhibition for c-DCE and VC, while the EV culture had lower Haldane inhibition constants for TCE, c-DCE, and VC of 900, 750, and 750 $\mu$M, respectively. The BM culture had better transformation abilities than the individual cultures over a wide range of PCE and TCE concentrations. Modeling results indicated that a combination of competitive and Haldane inhibition kinetics is required to simulate dechlorination over a broad range of concentrations up to the solubility limits of PCE and TCE.

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Toxicity Evaluation of Complex Metal Mixtures Using Reduced Metal Concentrations: Application to Iron Oxidation by Acidithiobacillus ferrooxidans

  • Cho, Kyung-Suk;Ryu, Hee-Wook;Choi, Hyung-Min
    • Journal of Microbiology and Biotechnology
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    • v.18 no.7
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    • pp.1298-1307
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    • 2008
  • In this study, we investigated the inhibition effects of single and mixed heavy metal ions ($Zn^{2+},\;Ni^{2+},\;Cu^{2+},\;and\;Cd^{2+}$) on iron oxidation by Acidithiobacillus ferrooxidans. Effects of metals on the iron oxidation activity of A. ferrooxidans are categorized into four types of patterns according to its oxidation behavior. The results indicated that the inhibition effects of the metals on the iron oxidation activity were noncompetitive inhibitions. We proposed a reduced inhibition model, along with the reduced inhibition constant ($\alpha_i$), which was derived from the inhibition constant ($K_I$) of individual metals and represented the tolerance of a given inhibitor relative to that of a reference inhibitor. This model was used to evaluate the toxicity effect (inhibition effect) of metals on the iron oxidation activity of A. ferrooxidans. The model revealed that the iron oxidation behavior of the metals, regardless of metal systems (single, binary, ternary, or quaternary), is closely matched to that of any reference inhibitor at the same reduced inhibition concentration, $[I]_{reduced}$, which defines the ratio of the inhibitor concentration to the reduced inhibition constant. The model demonstrated that single metal systems and mixed metal systems with the same reduced inhibitor concentrations have similar toxic effects on microbial activity.

Temperament, Parenting, and Behavioral Inhibition of Korean Toddlers (걸음마기 아동의 행동억제 : 아동의 기질 및 어머니의 양육행동과의 관계)

  • Chung, Ock Boon;Rubin, Kenneth;Park, Seong Yeon;Yoon, Chong Hee;Doh, Hyun Sim
    • Korean Journal of Child Studies
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    • v.23 no.4
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    • pp.71-88
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    • 2002
  • Mothers of 113 Korean toddlers completed Toddler Behavior Assessment Questionnaire(TBAQ) and Child Rearing Practice Report(CRPR). Observations of mother-child dyads in novel situations involving unfamiliar settings and adults assessed child's behavioral inhibition. Nonsocial inhibition were measured by the amount of time each child spent in physical contact with his/her mother in free-play episodes. Adult-social inhibition was based on child's behavior when an unfamiliar adult requested that the child approach her as she presented them with toys or activities. Results showed that TBAQ Social Fearfulness was positively associated with nonsocial and adult-social inhibition. TBAQ Pleasure was correlated negatively and TBAQ Anger Proneness positively correlated with adult-social inhibition. An interaction effect showed that child's social fearfulness and mother's overprotective behaviors affected adult-social inhibition. The regression model explained 31% of the variance.

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Suppressive Effects of Divalent Cations on Self-splicing Inhibition by Spectinomycin of Group 1 Intron RNA

  • Park, In-Kook
    • Journal of Microbiology
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    • v.37 no.4
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    • pp.243-247
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    • 1999
  • Effects of divalent cations on self-splicing inhibition by the antibiotic spectinomycin of the phage T4 thymidylate synthase intron (td) have been investigated. $Ca^{2+}$ ion at 1mM concentration suppressed splicing inhibition of spectinomycin by 10% and 50 ${\mu}M\;Co^{2+}$ ion also suppressed splicing inhibition of specinomycin by 10%. $Mg^{2+}$ ion at 6 mM concentration decreased splicing inhibition of spectinomycin by 42% while $Mn^{2+}$ ion decreased the splicing inhibition by 10%. $Zn^{2+}$ ion at 10 uM concentration lowered the splicing inhibition by spectinomycin of 15%. Of all divalent cations tested, $Mg^{2+}$ ion was the most effective in suppressing splicing inhibition by specinomycin whereas $Ca^{2+}$ ion was the least effective. The results suggest that spectinomycin may interact with specific and functional $Mg^{2+}$-binding sites within intron RNA that lead to a displacement of $Mg^{2+}$ essential for catalytic activity.

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Infant Emotionality, Parenting, and 3-Year Inhibition (영아기 정서성 및 부모의 양육행동에 따른 3세 아동의 행동억제)

  • 박성연
    • Journal of the Korean Home Economics Association
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    • v.36 no.4
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    • pp.19-34
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    • 1998
  • The purpose of this study was to examine early emotionality and mothering and fathering antecedents of inhibition of children at age 3 years in a sample of 100 children(51 boys; 49 girls). In order to assess child's behavioral inhibition and mothering, the behaviors of each child-mother dyad was videotaped in a structured lab situation. Data on Fathering behavior were gathered through questionnaires. 2X2ANOVA, Hierachical Regression Analyses and Fisher's Z test were conducted for the statistical analyses. The main results were as follows; 1) Only small portion of the variance in subsequent inhibition could be explained by early emotionality(i.e.negative, positive, and the interaction of both emotionality). 2) High negativity coupled with low positivity in infancy predicted high inhibition especially for girls. 3) In general, sensitive mothering and appropriateness of mothers' response were related to child's low inhibition, while parental intrusiveness and negative affect increased child's inhibition. 4) Mothering appeared more influential in the case of children who showed low positivity during infancy. The importance of distinguishing positive and negative emotionality in infancy and studying parental behavior to predict child's inhibition were discussed.

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Effects of Butachlor on Cell Division and Cell Enlargement in Oat (Avena sativa L.) (Utachlor가 귀리 (Avena sativa L.)의 세포분열 및 신장에 미치는 영향)

  • 김재철
    • Journal of Plant Biology
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    • v.29 no.3
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    • pp.167-173
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    • 1986
  • The effects of varying concentrations and durations of butachlor [N-(bytoxymethyl)-2-chlor-2', 6';-diethylacetanilide] treatment on oat (Avena sativa L.) root cell division were studied. Oats were treated from 0 to 48h with concentration ranging from 1$\times$10-6M to 1$\times$10-3M of butachlor. The highest concentration (1$\times$10-3M) of butachlor caused significant inhibition of cell division after 6h treatment. After 18h treatment, 49% and 66% inhibition of cell division occurred at 1$\times$10-5M and 1$\times$10-4M, respectively, while 16% inhibition of cell division occurred at 1$\times$10-6M concentration at same exposure period. Oat treated with 1$\times$10-5M and 1$\times$10-6M showed 69% and 38% inhibition of cell division after 36h. Increasing herbicide concentration at a specific time increased inhibition of cell division, and increasing the duration of treatment at a specific concentration also increased inhibition of cell division. In most instances the greatest inhibition of cell division occurred between 0 to 18h during 48h treatment. A range of concentration of 1$\times$10-5M to 1$\times$10-3M reduced cell enlargement significantly during 24h incubation period. The 1$\times$10-5M and 1$\times$10-3M caused 34% and 75% inhibition of cell enlargement. It was concluded that butachlor caused the growth inhibition of oats by inhibiting both cell division and cell enlargement.

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Screening of the Tyrosinase Inhibition and Hyaluronidase Inhibition Activities, and Radical Scavenging Effects Using Plants in Cheju (제주산 식물을 이용한 Tyrosinase 억제 활성, Hyaluronidase 억제 활성, 라디칼 소거 활성 검색)

  • Lee, Sun-Joo;Jung, Deok-Sang;Bu, Hee-Jeong;Yang, Hong-Chul;Riu, Key-Zung;Lee, Nam-Ho
    • Korean Journal of Pharmacognosy
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    • v.32 no.3
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    • pp.175-180
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    • 2001
  • Solvent extracts of 17 plants collected in Cheju Island were investigated for their biological properties related to cosmeceuticals such as tyrosinase and hyaluronidase inhibition and also radical scavenging effects. The chloroform fraction of Phytolacca esculenta root exhibited strong inhibition against tyrosinase activity. No fraction showed significant hyaluronidase inhibition. Some solvent extracts of plants such as Achyranthes japonica and Artemisia princeps showed considerable radical scavenging activities.

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