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Sample records for acid mediates long-paced

  1. Essential fatty acids and lipid mediators. Endocannabinoids

    G. Caramia

    2012-03-01

    Full Text Available In 1929 Burr and Burr discovered the essential fatty acids omega-6 and omega-3. Since then, researchers have shown a growing interest in polyunsaturated fatty acids (PUFA as precursors of “lipid mediator” molecules, often with opposing effects, prostaglandins, prostacyclins, thromboxanes, leukotrienes, lipossines, resolvines, protectines, maresins that regulate immunity, platelet aggregation, inflammation, etc. They showed that the balance between omega-3 and omega-6 acids has a profound influence on all the body’s inflammatory responses and a raised level of PUFA omega-3 in tissue correlate with a reduced incidence of degenerative cardiovascular disease, some mental illnesses such as depression, and neuro-degenerative diseases such as Alzheimer’s. The CYP-catalyzed epoxidation and hydroxylation of arachidonic acid (AA were established recently as the so-called third branch of AGE cascade. Cytochrome P450 (CYP epoxygenases convert AA to four epoxyeicosatrienoic acid (EET regioisomers, that produce vascular relaxation anti-inflammatory effects on blood vessels and in the kidney, promote angiogenesis, and protect ischemic myocardium and brain. Eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA are accessible to CYP enzymes in the same way as AA. Metabolites derived from EPA include epoxyeicosatetraenoic acids (EETR and hydroxyeicosapentaenoic acids (19- and 20-HEPE, whereas DHA include epoxydocosapentaenoic acids (EDPs hydroxydocosahexaenoic acids (21- and 22-HDoHE. For many of the CYP isoforms, the n-3 PUFAs are the preferred substrates and the available data suggest that some of the vasculo- and cardioprotective effects attributed to dietary n-3 PUFAs may be mediated by CYP-dependent metabolites of EPA and DHA. From AA derives also endocannabinoids like anandamide (N-arachidonoylethanolamine and 2-arachidonoylglycerol, capable of mimicking the pharmacological actions of the active principle of Cannabis sativa preparations such as

  2. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  3. Docosapentaenoic acid derived metabolites and mediators - The new world of lipid mediator medicine in a nutshell.

    Weylandt, Karsten-H

    2016-08-15

    Recent years have seen the description and elucidation of a new class of anti-inflammatory and pro-resolving lipid mediators. The arachidonic acid (AA)-derived compounds in this class are called lipoxins and have been described in great detail since their discovery thirty years ago. The new players are mediators derived from fish oil omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), called resolvins, protectins and maresins. Taken together, these mediators are also called specialized pro-resolution mediators (SPMs). As compared to the AA/EPA/DHA-derived compounds, research regarding mediators formed from the n-3 and n-6 docosapentaenoic acids (DPAn-3 and DPAn-6) is sparse. However, mono- di- and trihydroxy derivates of the DPAs have anti-inflammatory properties as well, even though mechanisms of their anti-inflammatory action have not been fully elucidated. This review aims to summarize current knowledge regarding the DPA-derived SPMs and their actions. PMID:26546723

  4. Copper(I) mediated cross-coupling of amino acid derived organozinc reagents with acid chlorides

    Hjelmgaard, Thomas; Tanner, David Ackland

    2006-01-01

    This paper describes the development of a straightforward experimental protocol for copper-mediated cross-coupling of amino acid derived beta-amido-alkylzinc iodides 1 and 3 with a range of acid chlorides. The present method uses CuCN center dot 2LiCl as the copper source and for organozinc reagent...

  5. Acid mediates a prolonged antinociception via substance P signaling in acid-induced chronic widespread pain

    Chen, Wei-Nan; Chen, Chih-Cheng

    2014-01-01

    Background Substance P is an important neuropeptide released from nociceptors to mediate pain signals. We recently revealed antinociceptive signaling by substance P in acid-sensing ion channel 3 (ASIC3)-expressing muscle nociceptors in a mouse model of acid-induced chronic widespread pain. However, methods to specifically trigger the substance P antinociception were still lacking. Results Here we show that acid could induce antinociceptive signaling via substance P release in muscle. We preve...

  6. Tannic acid-mediated green synthesis of antibacterial silver nanoparticles.

    Kim, Tae Yoon; Cha, Song-Hyun; Cho, Seonho; Park, Youmie

    2016-04-01

    The search for novel antibacterial agents is necessary to combat microbial resistance to current antibiotics. Silver nanoparticles (AgNPs) have been reported to be effective antibacterial agents. Tannic acid is a polyphenol compound from plants with antioxidant and antibacterial activities. In this report, AgNPs were prepared from silver ions by tannic acid-mediated green synthesis (TA-AgNPs). The reaction process was facile and involved mixing both silver ions and tannic acid. The absorbance at 423 nm in the UV-Visible spectra demonstrated that tannic acid underwent a reduction reaction to produce TA-AgNPs from silver ions. The synthetic yield of TA-AgNPs was 90.5 % based on inductively coupled plasma mass spectrometry analysis. High-resolution transmission electron microscopy and atomic force microscopy images indicated that spherical-shaped TA-AgNPs with a mean particle size of 27.7-46.7 nm were obtained. Powder high-resolution X-ray diffraction analysis indicated that the TA-AgNP structure was face-centered cubic with a zeta potential of -27.56 mV. The hydroxyl functional groups of tannic acid contributed to the synthesis of TA-AgNPs, which was confirmed by Fourier transform infrared spectroscopy. The in vitro antibacterial activity was measured using the minimum inhibitory concentration (MIC) method. The TA-AgNPs were more effective against Gram-negative bacteria than Gram-positive bacteria. The MIC for the TA-AgNPs in all of the tested strains was in a silver concentration range of 6.74-13.48 μg/mL. The tannic acid-mediated synthesis of AgNPs afforded biocompatible nanocomposites for antibacterial applications. PMID:26895244

  7. Photochemical decomposition of perfluorooctanoic acid mediated by iron in strongly acidic conditions

    Highlights: • Perfluorooctanoic acid (PFOA) was decomposed based on ferric ion performance. • Complete decomposition of PFOA was confirmed in strongly acidic conditions. • Fe2+ changed to Fe3+ to restore chemical equilibrium in this condition. • Fe3+ was only produced from Fe2+ by hydroxyl radical in weakly acidic conditions. • The Fe3+ regeneration mechanisms resulted in the performance of Fe3+ for PFOA. - Abstract: The performance of a ferric ion mediated photochemical process for perfluorooctanoic acid (PFOA) decomposition in strongly acidic conditions of pH 2.0 was evaluated in comparison with those in weakly acidic conditions, pH 3.7 or pH 5.0, based on iron species composition and ferric ion regeneration. Complete decomposition of PFOA under UV irradiation was confirmed at pH 2.0, whereas perfluoroheptanoic acid (PFHpA) and other intermediates were accumulated in weakly acidic conditions. Iron states at each pH were evaluated using a chemical equilibrium model, Visual MINTEQ. The main iron species at pH 2.0 is Fe3+ ion. Although Fe3+ ion is consumed and is transformed to Fe2+ ion by photochemical decomposition of PFOA and its intermediates, the produced Fe2+ ion will change to Fe3+ ion to restore chemical equilibrium. Continuous decomposition will occur at pH 2.0. However, half of the iron cannot be dissolved at pH 3.7. The main species of dissolved iron is Fe(OH)2+. At pH 3.7 or higher pH, Fe3+ ion will only be produced from the oxidation of Fe2+ ion by hydroxyl radical produced by Fe(OH)2+ under UV irradiation. These different mechanisms of Fe3+ regeneration that prevail in strongly and weakly acidic conditions will engender different performances of the ferric ion

  8. Mediated electrochemical oxidation of organic wastes using a Co (III) mediator in a nitric acid based system

    An electrochemical cell with a Co(III) mediator and nitric acid electrolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the mediator oxidizes the organics and insoluble transuranic compounds and is regenerated at the anode until the organics are converted to CO2. The nitric acid is an excellent oxidant that facilitates the destruction of the organic components. The anode is not readily attacked by the nitric acid solution, thus the cell can be used for extended continual operation without electrode replacement. 2 figs

  9. Saturated fatty acids trigger TLR4-mediated inflammatory response.

    Rocha, D M; Caldas, A P; Oliveira, L L; Bressan, J; Hermsdorff, H H

    2016-01-01

    Toll-like receptors (TLR) mediate infection-induced inflammation and sterile inflammation by endogenous molecules. Among the TLR family, TLR4 is the best understood. However, while its downstream signaling pathways have been well defined, not all ligands of TLR4 are currently known. Current evidence suggests that saturated fatty acids (SFA) act as non-microbial TLR4 agonists, and trigger its inflammatory response. Thus, our present review provides a new perspective on the potential mechanism by which SFAs could modulate TLR4-induced inflammatory responses: (1) SFAs can be recognized by CD14-TLR4-MD2 complex and trigger inflammatory pathways, similar to lipopolysaccharide (LPS). (2) SFAs lead to modification of gut microbiota with an overproduction of LPS after a high-fat intake, enhancing this natural TLR4 ligand. (3) In addition, this metabolic endotoxemia leads to an oxidative stress thereby producing atherogenic lipids - oxLDL and oxidized phospholipids - which trigger CD36-TLR4-TLR6 inflammatory response. (4) Also, the high SFA consumption increases the lipemia and the mmLDL and oxLDL formation through oxidative modifications of LDL. The mmLDL, unlike oxLDL, is involved in activation of the CD14-TLR4-MD2 inflammatory pathway. Those molecules can induce TLR4 inflammatory response by MyD88-dependent and/or MyD88-independent pathways that, in turn, promotes the expression of proinflammatory transcript factors such as factor nuclear kappa B (NF-κB), which plays a crucial role in the induction of inflammatory mediators (cytokines, chemokines, or costimulatory molecules) implicated in the development and progression of many chronic diseases. PMID:26687466

  10. Cetalox and analogues: synthesis via acid-mediated polyene cyclizations.

    Snowden, Roger L

    2008-06-01

    Using a novel, acid-mediated cyclization methodology, a direct access to Cetalox ((+/-)-1; a commercially important ambergris-type odorant) and various structurally related didehydro (i.e., 19, 26, and 30) and tetradehydro (i.e., 28 and 37/38) analogues is described. Treatment of either (E,E)-14 or (E)-15 with an excess of FSO(3)H in 2-nitropropane at -90 degrees stereospecifically afforded (+/-)-1 in 40 and 42% yield, respectively. Under similar conditions, cyclization of (E)-18 or 20 furnished 19 in 60 and 64% yield, respectively. Analogously, using an excess of ClSO(3)H in CH(2)Cl(2) at -80 degrees, 26 is formed with high stereoselectivity by cyclization of either (E)-24 or (Z)-25 (52 and 31% yield, resp.); in the same manner, 28 was prepared from 27 (22% yield). The same principle was applied to the synthesis of racemic Superambrox (30), via cyclization of 35, but only with poor selectivity (22%) and low yield (7%). Another approach via cyclization of (E)-40 under solvolysis conditions (excess TFA in CH(2)Cl(2) at -10 degrees) gave a higher yield (15%) with improved selectivity (43%). Finally, cyclization of 34 (1:1 diastereoisomer mixture) afforded 37/38 (10:1) in 27% yield. The qualitative organoleptic properties of 19, 26, 28, 30, and 37/38 (10:1) are briefly discussed. PMID:18618391

  11. Retinoic Acid-mediated Nuclear Receptor Activation and Hepatocyte Proliferation

    Bushue, Nathan; Wan, Yu-Jui Yvonne

    2016-01-01

    Due to their well-known differentiation and apoptosis-inducing abilities, retinoic acid (RA) and its analogs have strong anti-cancer efficacy in human cancers. However, in vivo RA is a liver mitogen. While speculation has persisted that RA-mediated signaling is likely involved in hepatocyte proliferation during liver regeneration, direct evidence is still required. Findings in support of this proposition include observations that a release of retinyl palmitate (the precursor of RA) occurs in liver stellate cells following liver injury. Nevertheless, the biological action of this released vitamin A is virtually unknown. More likely is that the released vitamin A is converted to RA, the biological form, and then bound to a specific receptor (retinoid x receptor; RXRα), which is most abundantly expressed in the liver. Considering the mitogenic effects of RA, the RA-activated RXRα would likely then influence hepatocyte proliferation and liver tissue repair. At present, the mechanism by which RA stimulates hepatocyte proliferation is largely unknown. This review summarizes the activation of nuclear receptors (peroxisome proliferator activated receptor-α, pregnane x receptor, constitutive androstane receptor, and farnesoid x receptor) in an RXRα dependent manner to induce hepatocyte proliferation, providing a link between RA and its proliferative role.

  12. Peptide nucleic acid (PNA) binding-mediated gene regulation

    2004-01-01

    Peptide nucleic acids (PNAs) are synthetic oligonucleotides with chemically modified backbones. PNAs can bind to both DNA and RNA targets in a sequence-specific manner to form PNA/DNA and PNA/RNA duplex structures. When bound to double-stranded DNA (dsDNA) targets, the PNA molecule replaces one DNA strand in the duplex by strand invasion to form a PNA/DNA/PNA [or (PNA)2/DNA] triplex structure and the displaced DNA strand exists as a singlestranded D-loop. PNA has been used in many studies as research tools for gene regulation and gene targeting. The Dloops generated from the PNA binding have also been demonstrated for its potential in initiating transcription and inducing gene expression. PNA provides a powerful tool to study the mechanism of transcription and an innovative strategy to regulate target gene expression. An understanding of the PNA-mediated gene regulation will have important clinical implications in treatment of many human diseases including genetic, cancerous, and age-related diseases.

  13. Photochemical decomposition of perfluorooctanoic acid mediated by iron in strongly acidic conditions

    Ohno, Masaki, E-mail: mohno@hiroshima-u.ac.jp [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Ito, Masataka; Ohkura, Ryouichi [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Mino A, Esteban R. [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Kose, Tomohiro [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Okuda, Tetsuji [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Nakai, Satoshi [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Kawata, Kuniaki [Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Akiha-ku, Niigata 956-8603 (Japan); Nishijima, Wataru [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan)

    2014-03-01

    Highlights: • Perfluorooctanoic acid (PFOA) was decomposed based on ferric ion performance. • Complete decomposition of PFOA was confirmed in strongly acidic conditions. • Fe{sup 2+} changed to Fe{sup 3+} to restore chemical equilibrium in this condition. • Fe{sup 3+} was only produced from Fe{sup 2+} by hydroxyl radical in weakly acidic conditions. • The Fe{sup 3+} regeneration mechanisms resulted in the performance of Fe{sup 3+} for PFOA. - Abstract: The performance of a ferric ion mediated photochemical process for perfluorooctanoic acid (PFOA) decomposition in strongly acidic conditions of pH 2.0 was evaluated in comparison with those in weakly acidic conditions, pH 3.7 or pH 5.0, based on iron species composition and ferric ion regeneration. Complete decomposition of PFOA under UV irradiation was confirmed at pH 2.0, whereas perfluoroheptanoic acid (PFHpA) and other intermediates were accumulated in weakly acidic conditions. Iron states at each pH were evaluated using a chemical equilibrium model, Visual MINTEQ. The main iron species at pH 2.0 is Fe{sup 3+} ion. Although Fe{sup 3+} ion is consumed and is transformed to Fe{sup 2+} ion by photochemical decomposition of PFOA and its intermediates, the produced Fe{sup 2+} ion will change to Fe{sup 3+} ion to restore chemical equilibrium. Continuous decomposition will occur at pH 2.0. However, half of the iron cannot be dissolved at pH 3.7. The main species of dissolved iron is Fe(OH){sup 2+}. At pH 3.7 or higher pH, Fe{sup 3+} ion will only be produced from the oxidation of Fe{sup 2+} ion by hydroxyl radical produced by Fe(OH){sup 2+} under UV irradiation. These different mechanisms of Fe{sup 3+} regeneration that prevail in strongly and weakly acidic conditions will engender different performances of the ferric ion.

  14. Hemin-mediated Hemolysis in Erythrocytes: Effects of Ascorbic Acid and Glutathione

    Shu-De LI; Yan-Dan SU; Ming LI; Cheng-Gang ZOU

    2006-01-01

    In the present work, we investigated the effect of ascorbic acid and glutathione on hemolysis induced by hemin in erythrocytes. Ascorbic acid not only enhanced hemolysis, but also induced formation of thiobarbituric acid-reactive substances in the presence of hemin. It has been shown that glutathione inhibits hemin-induced hemolysis by mediating hemin degradation. Erythrocytes depleted of glutathione became very sensitive to oxidative stress induced by hemin and ascorbic acid. H2O2 was involved in heminmediated hemolysis in the presence of ascorbic acid. However, a combination of glutathione and ascorbic acid was more effective in inhibiting hemolysis induced by hemin than glutathione alone. Extracellular and intracellular ascorbic acid exhibited a similar effect on hemin-induced hemolysis or inhibition of hemininduced hemolysis by glutathione. The current study indicates that ascorbic acid might function as an antioxidant or prooxidant in hemin-mediated hemolysis, depending on whether glutathione is available.

  15. Enzymatically mediated incorporation of 2-chlorophenol 4-chlorophenol into humic acids

    Lassen, P.; Randall, A.; Jørgensen, O.;

    1994-01-01

    A possible route to chlorinated humic substances in the environment, is an indirect chlorination of humic material by enzymatically mediated incorporation of low molecular weight organo-chlorine compounds into the humic skeleton. The enzymatically mediated incorporation of 2-chlorophenol and 4......-chlorophenol into humic acids by Horseradish Peroxidase is reported. The incorporation is accompanied by a significant polymerization of the chlorophenols. The stability of the chlorinated humic acids as well as the environmental implication are discussed....

  16. α-Linolenic acid prevents endoplasmic reticulum stress-mediated apoptosis of stearic acid lipotoxicity on primary rat hepatocytes

    Shi Hongyang

    2011-05-01

    Full Text Available Abstract Aims Lipid accumulation in non-adipose tissues leads to cell dysfunction and apoptosis, a phenomenon known as lipotoxicity. Unsaturated fatty acids may offset the lipotoxicity associated with saturated fatty acids. Stearic acid induced endoplasmic reticulum (ER stress and caused apoptotic and necrotic cell death in the primary rat hepatocytes. Methods Cell viability was investigated using MTT assay, and apoptosis was evaluated with Hoechst 33342 staining. Western blot analysis was used to examine the changes in the expression levels of glucose regulated protein 78 (GRP78, glucose regulated protein 94 (GRP94, and C/EBP homologous protein (CHOP. Caspase-3 activity was evaluated using a Caspase-3 substrate kit. Results We have studied the ability of α-linolenic acid to prevent endoplasmic reticulum stress-mediated apoptosis of rat hepatocytes elicited by stearic acid and thapsigargin. Incubation of primary rat hepatocytes for 16 h with stearic acid produced a significant increase in cell death. Stearic acid also increased levels of three indicators of ER stress -- GRP78, CHOP, and GRP94. α-Linolenic acid distinctly reduced cell death and levels of all three indicators of ER stress brought about by stearic acid. Thapsigargin, which induces ER stress produced similar effects to those obtained using stearic acid; its effects were partly reversed by α-linolenic acid. Conclusion These results suggest that α-linolenic acid prevents ER stress-mediated apoptosis of stearic acid lipotoxicity on primary rat hepatocytes might become a target to develop new antiapoptotic compounds in nonalcoholic fatty liver disease (NAFLD.

  17. The protective effect of salicylic acid on lysozyme against riboflavin-mediated photooxidation

    Li, Kun; Wang, Hongbao; Cheng, Lingli; Zhu, Hui; Wang, Mei; Wang, Shi-Long

    2011-06-01

    As a metabolite of aspirin in vivo, salicylic acid was proved to protect lysozyme from riboflavin-mediated photooxidation in this study. The antioxidative properties of salicylic acid were further studied by using time-resolved laser flash photolysis of 355 nm. It can quench the triplet state of riboflavin via electron transfer from salicylic acid to the triplet state of riboflavin with a reaction constant of 2.25 × 10 9 M -1 s -1. Mechanism of antioxidant activities of salicylic acid on lysozyme oxidation was discussed. Salicylic acid can serve as a potential antioxidant to quench the triplet state of riboflavin and reduce oxidative pressure.

  18. Synthetic Fatty Acids Prevent Plasmid-Mediated Horizontal Gene Transfer

    Getino Redondo, María; Sanabria Ríos, David J.; Fernández López, Raúl; Campos Gómez, Javier; Sánchez López, José M.; Fernández Medarde, Antonio; Carballeira Cabranes, Néstor M.; Cruz Calahorra, Fernando de la

    2015-01-01

    Bacterial conjugation constitutes a major horizontal gene transfer mechanism for the dissemination of antibiotic resistance genes among human pathogens. Antibiotic resistance spread could be halted or diminished by molecules that interfere with the conjugation process. In this work, synthetic 2-alkynoic fatty acids were identified as a novel class of conjugation inhibitors. Their chemical properties were investigated by using the prototype 2-hexadecynoic acid and its derivatives. Essential fe...

  19. Fulvic Acid Mediated Photolysis of Ibuprofen in Water.

    Photolysis of the nonsteroidal anti-inflammatory drug ibuprofen was studied in solutions of fulvic acid (FA) isolated from Pony Lake, Antarctica; Suwannee River, GA, USA; and Old Woman Creek, OH, USA. At an initial concentration of 10 µM ibuprofen degrades by direct photolysis...

  20. New insights into the acid mediated disproportionation of pentavalent uranyl

    Mougel, Victor; Biswas, Biplab; Pecaut, Jacques; Mazzanti, Marinella [Laboratoire de Reconnaissance Ionique et Chimie de Coordination, SCIB, UMR-E 3 CEA-UJF FRE 3200 CNRS, INAC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France)

    2010-07-01

    The reaction of benzoic acid with the uranyl(V) complex [(UO{sub 2}Py{sub 5})(KI{sub 2}Py{sub 2})] in pyridine leads to immediate disproportionation with formation of a hexa-nuclear U(IV) benzoate cluster, a bis-benzoate complex of uranyl(VI) and water. (authors)

  1. Fatty acid transporter CD36 mediates hypothalamic effect of fatty acids on food intake in rats.

    Valentine S Moullé

    Full Text Available Variations in plasma fatty acid (FA concentrations are detected by FA sensing neurons in specific brain areas such as the hypothalamus. These neurons play a physiological role in the control of food intake and the regulation of hepatic glucose production. Le Foll et al. previously showed in vitro that at least 50% of the FA sensing in ventromedial hypothalamic (VMH neurons is attributable to the interaction of long chain FA with FA translocase/CD36 (CD36. The present work assessed whether in vivo effects of hypothalamic FA sensing might be partly mediated by CD36 or intracellular events such as acylCoA synthesis or β-oxidation. To that end, a catheter was implanted in the carotid artery toward the brain in male Wistar rats. After 1 wk recovery, animals were food-deprived for 5 h, then 10 min infusions of triglyceride emulsion, Intralipid +/- heparin (IL, IL(H, respectively or saline/heparin (SH were carried out and food intake was assessed over the next 5 h. Experimental groups included: 1 Rats previously injected in ventromedian nucleus (VMN with shRNA against CD36 or scrambled RNA; 2 Etomoxir (CPT1 inhibitor or saline co-infused with IL(H/S(H; and 3 Triacsin C (acylCoA synthase inhibitor or saline co-infused with IL(H/S(H. IL(H significantly lowered food intake during refeeding compared to S(H (p<0.001. Five hours after refeeding, etomoxir did not affect this inhibitory effect of IL(H on food intake while VMN CD36 depletion totally prevented it. Triacsin C also prevented IL(H effects on food intake. In conclusion, the effect of FA to inhibit food intake is dependent on VMN CD36 and acylCoA synthesis but does not required FA oxidation.

  2. Ionic liquid mediated esterification of alcohol with acetic acid

    Beilei ZHOU; Yanxiong FANG; Hao GU; Saidan ZHANG; Baohua HUANG; Kun ZHANG

    2009-01-01

    Highly efficient esterification of alcohols with acetic acid by using a Bransted acidic ionic liquid, i.e., 1-methyl-2-pyrrolidonium hydrogen sulfate ([Hnmp]HSo4), as catalyst has been realized. The turnover numbers (TON) were able to reach up to 11000 and turnover frequency (TOF) was 846. The catalytic system is suitable for the esterification of long chain aliphatic alcohols, benzyl alcohol and cyclohexanol with good yields of esters. The procedure of separating the product and catalyst is simple, and the catalyst could be reused. [Hnmp]HSO4 had much weaker corrosiveness than H2SO4. The corrosive rate of H2SO4 was 400 times more than that of [Hnmp]HSO4 to stainless steel.

  3. Hyaluronic acid: A promising mediator for periodontal regeneration

    Bansal Jyoti; Kedige Suresh; Anand Samir

    2010-01-01

    Hyaluronic acid (HA) is a natural-non sulphated high molecular weight glycosaminoglycan that forms a critical component of the extracellular matrix and contributes significantly to tissue hydrodynamics, cell migration and proliferation. The use of HA in the treatment of inflammatory process is established in medical areas such as orthopedics, dermatology and ophthalmology. In the field of dentistry, hyaluronate has shown anti-inflammatory, antiedematous and anti-bacterial effects for the trea...

  4. Ferulic acid reverses ABCB1-mediated paclitaxel resistance in MDR cell lines.

    Muthusamy, Ganesan; Balupillai, Agilan; Ramasamy, Karthikeyan; Shanmugam, Mohana; Gunaseelan, Srithar; Mary, Beaulah; Prasad, N Rajendra

    2016-09-01

    Multidrug resistance (MDR) remains a major obstacle in cancer chemotherapy. The use of the dietary phytochemicals as chemosensitizing agents to enhance the efficacy of conventional cytostatic drugs has recently gained the attention as a plausible approach for overcoming the drug resistance. The aim of this study was to investigate whether a naturally occurring diet-based phenolic acid, ferulic acid, could sensitize paclitaxel efficacy in ABCB1 overexpressing (P-glycoprotein) colchicine selected KB Ch(R)8-5 cell line. In vitro drug efflux assays demonstrated that ferulic acid inhibits P-glycoprotein transport function in drug resistant KB Ch(R)8-5 cell lines. However, ferulic acid significantly downregulates ABCB1 expression in a concentration dependent manner. Cytotoxicity assay reveals that ferulic acid decreased paclitaxel resistance in KBCh(R)8-5 and HEK293/ABCB1 cells, which indicates its chemosensitizing potential. Clonogenic cell survival assay and apoptotic morphological staining further confirm the chemosensitizing potential of ferulic acid in drug resistant KB Ch(R)8-5 cell lines. Ferulic acid treatment enhances paclitaxel mediated cell cycle arrest and upregulates paclitaxel-induced apoptotic signaling in KB resistant cells. Hence, it has been concluded that downregulation of ABCB1 and subsequent induction of paclitaxel-mediated cell cycle arrest and apoptotic signaling may be the cause for the chemosensitizing potential of ferulic acid in P-gp overexpressing cell lines. PMID:27262378

  5. [Free fatty acids: mediators of insulin resistance and atherosclerosis].

    Castro Cabezas, M; Erkelens, D W; van Dijk, H

    2002-01-19

    Free fatty acids (FFAs) are involved in the transportation of energy; in the postprandial phase to the peripheral tissues and in the postabsorptive phase from the adipose tissue to the liver. In the postprandial phase, FFAs are mainly derived from hydrolysis of triglyceride-rich particles like chylomicrons and very low-density lipoproteins (VLDL). The flux of FFAs is directed to peripheral cells such as adipocytes and muscle cells. In the postabsorptive period, FFAs are transported to the liver after being released from intracellular storage in the adipocytes. Complement component 3 (C3) plays an important role in the uptake of free fatty acids by the peripheral cells and their esterification to triglycerides. Since C3 is also involved in the pathogenesis of the insulin resistance syndrome, and since a deviant FFA metabolism with an increased FFA flux to the liver may induce insulin resistance, it is hypothesized that C3 may form the missing link between FFA metabolism and insulin resistance. In addition, recent studies have increasingly indicated that atherosclerosis is in fact an inflammation-based process involving complement-dependent responses, in which FFAs seem to play a role in the complement-dependent pathway. It has recently become apparent that FFAs have a regulatory function in the transcription of DNA, in relation to lipoprotein metabolism. This is where PPAR-gamma and PPAR-alpha agonists ('glitazones' and fibrates respectively) are active (PPAR is an abbreviation for peroxisome proliferation activating receptor). Glitazons may play an important role in the treatment of insulin resistance and related disorders. Acquiring more knowledge about the relationship between complement and FFA metabolism may increase our understanding of these processes and provide openings for the development of new antiatherogenic strategies. PMID:11826668

  6. Mfge8 promotes obesity by mediating the uptake of dietary fats and serum fatty acids

    Khalifeh-Soltani, Amin; McKleroy, William; Sakuma, Stephen; Cheung, Yuk Yin; Tharp, Kevin; Qiu, Yifu; Turner, Scott M; Chawla, Ajay; Stahl, Andreas; Atabai, Kamran

    2014-01-01

    Fatty acids are integral mediators of energy storage, membrane formation and cell signaling. The pathways that orchestrate uptake of fatty acids remain incompletely understood. Expression of the integrin ligand Mfge8 is increased in human obesity and in mice on a high-fat diet, but its role in obesity is unknown. We show here that Mfge8 promotes the absorption of dietary triglycerides and the cellular uptake of fatty acid and that Mfge8-deficient (Mfge8−/−) mice are protected from diet-induce...

  7. Redox-Mediated Suberoylanilide Hydroxamic Acid Sensitivity in Breast Cancer

    Chiaradonna, Ferdinando; Barozzi, Iros; Miccolo, Claudia; Bucci, Gabriele; Palorini, Roberta; Fornasari, Lorenzo; Botrugno, Oronza A.; Pruneri, Giancarlo; Masullo, Michele; Passafaro, Alfonso; Galimberti, Viviana E.; Fantin, Valeria R.; Richon, Victoria M.; Pece, Salvatore; Viale, Giuseppe; Di Fiore, Pier Paolo; Draetta, Giulio; Pelicci, Pier Giuseppe

    2015-01-01

    Abstract Aims: Vorinostat (suberoylanilide hydroxamic acid; SAHA) is a histone deacetylase inhibitor (HDACi) approved in the clinics for the treatment of T-cell lymphoma and with the potential to be effective also in breast cancer. We investigated the responsiveness to SAHA in human breast primary tumors and cancer cell lines. Results: We observed a differential response to drug treatment in both human breast primary tumors and cancer cell lines. Gene expression analysis of the breast cancer cell lines revealed that genes involved in cell adhesion and redox pathways, especially glutathione metabolism, were differentially expressed in the cell lines resistant to SAHA compared with the sensitive ones, indicating their possible association with drug resistance mechanisms. Notably, such an association was also observed in breast primary tumors. Indeed, addition of buthionine sulfoximine (BSO), a compound capable of depleting cellular glutathione, significantly enhanced the cytotoxicity of SAHA in both breast cancer cell lines and primary breast tumors. Innovation: We identify and validate transcriptional differences in genes involved in redox pathways, which include potential predictive markers of sensitivity to SAHA. Conclusion: In breast cancer, it could be relevant to evaluate the expression of antioxidant genes that may favor tumor resistance as a factor to consider for potential clinical application and treatment with epigenetic drugs (HDACis). Antioxid. Redox Signal. 23, 15–29. PMID:25897982

  8. CD36 Mediated Fatty Acid-Induced Podocyte Apoptosis via Oxidative Stress.

    Wei Hua

    Full Text Available Hyperlipidemia-induced apoptosis mediated by fatty acid translocase CD36 is associated with increased uptake of ox-LDL or fatty acid in macrophages, hepatocytes and proximal tubular epithelial cells, leading to atherosclerosis, liver damage and fibrosis in obese patients, and diabetic nephropathy (DN, respectively. However, the specific role of CD36 in podocyte apoptosis in DN with hyperlipidemia remains poorly investigated.The expression of CD36 was measured in paraffin-embedded kidney tissue samples (Ctr = 18, DN = 20 by immunohistochemistry and immunofluorescence staining. We cultured conditionally immortalized mouse podocytes (MPC5 and treated cells with palmitic acid, and measured CD36 expression by real-time PCR, Western blot analysis and immunofluorescence; lipid uptake by Oil red O staining and BODIPY staining; apoptosis by flow cytometry assay, TUNEL assay and Western blot analysis; and ROS production by DCFH-DA fluorescence staining. All statistical analyses were performed using SPSS 21.0 statistical software.CD36 expression was increased in kidney tissue from DN patients with hyperlipidemia. Palmitic acid upregulated CD36 expression and promoted its translocation from cytoplasm to plasma membrane in podocytes. Furthermore, palmitic acid increased lipid uptake, ROS production and apoptosis in podocytes, Sulfo-N-succinimidyloleate (SSO, the specific inhibitor of the fatty acid binding site on CD36, decreased palmitic acid-induced fatty acid accumulation, ROS production, and apoptosis in podocytes. Antioxidant 4-hydroxy-2,2,6,6- tetramethylpiperidine -1-oxyl (tempol inhibited the overproduction of ROS and apoptosis in podocytes induced by palmitic acid.CD36 mediated fatty acid-induced podocyte apoptosis via oxidative stress might participate in the process of DN.

  9. Cerebral Ischemia Mediates the Effect of Serum Uric Acid on Cognitive Function

    Vannorsdall, Tracy D.; Jinnah, H.A.; Gordon, Barry; Kraut, Michael; Schretlen, David J.

    2016-01-01

    Background and Purpose High normal concentrations of serum uric acid (UA) are associated with mild cognitive dysfunction and increased cerebral ischemia as indexed by white matter hyperintensity volumes. We hypothesized that individual differences in white matter hyperintensities mediate the association between UA and mild cognitive dysfunction. Methods One hundred eighty community-dwelling adults aged 20 to 96 years completed neuropsychological testing, laboratory blood studies, and a brain MRI scan. Results Serum UA was associated (Pischemia might mediate the association between UA and cognitive dysfunction. Even mild elevations in UA appear to contribute to structural and functional brain changes. PMID:18772442

  10. Altered Cultivar Resistance of Kimchi Cabbage Seedlings Mediated by Salicylic Acid, Jasmonic Acid and Ethylene

    Lee, Young Hee; Kim, Sang Hee; Yun, Byung-Wook; Hong, Jeum Kyu

    2014-01-01

    Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultiva...

  11. TGF-β-SMAD3 signaling mediates hepatic bile acid and phospholipid metabolism following lithocholic acid-induced liver injury.

    Matsubara, Tsutomu; Tanaka, Naoki; Sato, Misako; Kang, Dong Wook; Krausz, Kristopher W; Flanders, Kathleen C; Ikeda, Kazuo; Luecke, Hans; Wakefield, Lalage M; Gonzalez, Frank J

    2012-12-01

    Transforming growth factor-β (TGFβ) is activated as a result of liver injury, such as cholestasis. However, its influence on endogenous metabolism is not known. This study demonstrated that TGFβ regulates hepatic phospholipid and bile acid homeostasis through MAD homolog 3 (SMAD3) activation as revealed by lithocholic acid-induced experimental intrahepatic cholestasis. Lithocholic acid (LCA) induced expression of TGFB1 and the receptors TGFBR1 and TGFBR2 in the liver. In addition, immunohistochemistry revealed higher TGFβ expression around the portal vein after LCA exposure and diminished SMAD3 phosphorylation in hepatocytes from Smad3-null mice. Serum metabolomics indicated increased bile acids and decreased lysophosphatidylcholine (LPC) after LCA exposure. Interestingly, in Smad3-null mice, the metabolic alteration was attenuated. LCA-induced lysophosphatidylcholine acyltransferase 4 (LPCAT4) and organic solute transporter β (OSTβ) expression were markedly decreased in Smad3-null mice, whereas TGFβ induced LPCAT4 and OSTβ expression in primary mouse hepatocytes. In addition, introduction of SMAD3 enhanced the TGFβ-induced LPCAT4 and OSTβ expression in the human hepatocellular carcinoma cell line HepG2. In conclusion, considering that Smad3-null mice showed attenuated serum ALP activity, a diagnostic indicator of cholangiocyte injury, these results strongly support the view that TGFβ-SMAD3 signaling mediates an alteration in phospholipid and bile acid metabolism following hepatic inflammation with the biliary injury. PMID:23034213

  12. Golgi-mediated post-translational processing of secretory acid phosphatase by Leishmania donovani promastigotes.

    Bates, P A; Hermes, I; Dwyer, D M

    1990-03-01

    Monensin, an inhibitor of Golgi function, was used to investigate the role of this cell compartment in the glycosylation of Leishmania donovani promastigote secretory acid phosphatase (EC 3.1.3.2). Monensin-treated cells demonstrated morphological changes in the Golgi complex and secreted enzyme with an altered electrophoretic mobility: two discrete bands of approximately 95 and 110 kDa were found, as compared to the heterodisperse nature of the enzyme from untreated controls. Chemical deglycosylation by mild acid hydrolysis resulted in a similar effect on the electrophoretic mobility of purified extracellular enzyme. Acid phosphatase was also treated with N-glycosidase F (EC 3.5.1.52) to remove N-linked oligosaccharides. The altered lectin-binding properties of the enzyme after these two treatments demonstrated that an unusual type of galactose-containing acid-labile carbohydrate was present in secretory acid phosphatase in addition to the N-linked oligosaccharides. Further, experiments with 32P-labelled enzyme indicated that phosphodiester bonds were the structural component responsible for the sensitivity of this carbohydrate to mild acid hydrolysis. Cumulatively, these results demonstrated that a novel form of Golgi-mediated posttranslational modification had occurred to the secretory acid phosphatase presumably by the addition of an acid-labile phosphoglycan. PMID:2320058

  13. Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl−/OH− exchange

    Singla, Amika; Dwivedi, Alka; Saksena, Seema; Gill, Ravinder K.; Alrefai, Waddah A.; RAMASWAMY, KRISHNAMURTHY; Dudeja, Pradeep K.

    2009-01-01

    Lysophosphatidic acid (LPA), a potent bioactive phospholipid, is a natural component of food products like soy and egg yolk. LPA modulates a number of epithelial functions and has been shown to inhibit cholera toxin-induced diarrhea. Antidiarrheal effects of LPA are known to be mediated by inhibiting chloride secretion. However, the effects of LPA on chloride absorption in the mammalian intestine are not known. The present studies examined the effects of LPA on apical Cl−/OH− exchangers known...

  14. Retinoic acid decreases the severity of Salmonella enterica serovar Typhimurium mediated gastroenteritis in a mouse model.

    Sinha, Ritam; Howlader, Debaki Ranjan; Mukherjee, Priyadarshini; Rai, Sulabh; Nag, Dhrubajyoti; Koley, Hemanta

    2016-07-01

    Gastroenteritis is a global burden; it's the major cause of morbidity and mortality both in adults and children of developing countries. Salmonella is one of the leading causes of bacteria-mediated gastroenteritis and due to its increasing multidrug antibiotic resistance; Salmonella-mediated gastroenteritis is difficult to control. Retinoic acid, the biologically active agent of vitamin A has an anti-inflammatory effect on experimental colitis. In this study we have shown All trans retinoic acid (ATRA) treatment down regulates Salmonella-mediated colitis in a murine model. Macroscopic signs of inflammation such as decrease in body weight and cecum weight, shorter length of proximal colon and pathological score of colitis were observed less in ATRA treated mice than in a vehicle control group. ATRA treatment not only reduced pro-inflammatory cytokine responses, such as TNF-α, IL-6, IL-1β, IFN-γ and IL-17 production but also increased IL-10 response in the supernatant of intestinal tissue. Results also suggested that ATRA treatment enhances the number of FoxP3-expressing T regulatory cells in MLN and also decreases bacterial load in systemic organs. We concluded that ATRA treatment indeed reduces Salmonella Typhimurium-mediated gastroenteritis in mice, suggesting it could be an important part of an alternative therapeutic approach to combat the disease. PMID:26858186

  15. Lipids in salicylic acid-mediated defense in plants: focusing on the roles of phosphatidic acid and phosphatidylinositol 4-phosphate

    Qiong eZhang

    2015-05-01

    Full Text Available Plants have evolved effective defense strategies to protect themselves from various pathogens. Salicylic acid (SA is an essential signaling molecule that mediates pathogen-triggered signals perceived by different immune receptors to induce downstream defense responses. While many proteins play essential roles in regulating SA signaling, increasing evidence also supports important roles for signaling phospholipids in this process. In this review, we collate the experimental evidence in support of the regulatory roles of two phospholipids, phosphatidic acid (PA and phosphatidylinositol 4-phosphate (PI4P, and their metabolizing enzymes in plant defense, and examine the possible mechanistic interaction between phospholipid signaling and SA-dependent immunity with a particular focus on the immunity-stimulated biphasic PA production that is reminiscent of and perhaps mechanistically connected to the biphasic reactive oxygen species (ROS generation and SA accumulation during defense activation.

  16. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    Junker, L.H.; Davis, R.A. (Univ. of Colorado Health Sciences Center, Denver (USA))

    1989-12-01

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of (14C)cholesterol from (2-14C)acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of (14C)cholesterol from (2-14C)acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis.

  17. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of [14C]cholesterol from [2-14C]acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of [14C]cholesterol from [2-14C]acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis

  18. Effect of Chicoric Acid on Mast Cell-Mediated Allergic Inflammation in Vitro and in Vivo.

    Lee, Na Young; Chung, Kyung-Sook; Jin, Jong Sik; Bang, Keuk Soo; Eom, Ye-Jin; Hong, Chul-Hee; Nugroho, Agung; Park, Hee-Jun; An, Hyo-Jin

    2015-12-24

    Chicoric acid (dicaffeoyl-tartaric acid), is a natural phenolic compound found in a number of plants, such as chicory (Cichorium intybus) and Echinacea (Echinacea purpurea), which possesses antioxidant, anti-inflammatory, antiviral, and analgesic activities. Although these biological effects of chicoric acid have been investigated, there are no reports of its antiallergic-related anti-inflammatory effects in human mast cells (HMC)-1 or anaphylactic activity in a mouse model. Therefore, we investigated the antiallergic-related anti-inflammatory effect of chicoric acid and its underlying mechanisms of action using phorbol-12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated HMC-1 cells. Chicoric acid decreased the mRNA expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β. We studied the inhibitory effects of chicoric acid on the nuclear translocation of nuclear factor kappa B (NF-κB) and activation of caspase-1. However, mitogen-activated protein kinase (MAPK) activation was not sufficient to abrogate the stimulus. In addition, we investigated the ability of chicoric acid to inhibit compound 48/80-induced systemic anaphylaxis in vivo. Oral administration of chicoric acid at 20 mg/kg inhibited histamine release and protected mice against compound 48/80-induced anaphylactic mortality. These results suggest that chicoric acid has an antiallergic-related anti-inflammatory effect that involves modulating mast cell-mediated allergic responses. Therefore, chicoric acid could be an efficacious agent for allergy-related inflammatory disorders. PMID:26593037

  19. Substrate-specific effects of pirinixic acid derivatives on ABCB1-mediated drug transport.

    Michaelis, Martin; Rothweiler, Florian; Wurglics, Mario; Aniceto, Natália; Dittrich, Michaela; Zettl, Heiko; Wiese, Michael; Wass, Mark; Ghafourian, Taravat; Schubert-Zsilavecz, Manfred; Cinatl, Jindrich

    2016-03-01

    Pirinixic acid derivatives, a new class of drug candidates for a range of diseases, interfere with targets including PPARα, PPARγ, 5-lipoxygenase (5-LO), and microsomal prostaglandin and E2 synthase-1 (mPGES1). Since 5-LO, mPGES1, PPARα, and PPARγ represent potential anti-cancer drug targets, we here investigated the effects of 39 pirinixic acid derivatives on prostate cancer (PC-3) and neuroblastoma (UKF-NB-3) cell viability and, subsequently, the effects of selected compounds on drug-resistant neuroblastoma cells. Few compounds affected cancer cell viability in low micromolar concentrations but there was no correlation between the anti-cancer effects and the effects on 5-LO, mPGES1, PPARα, or PPARγ. Most strikingly, pirinixic acid derivatives interfered with drug transport by the ATP-binding cassette (ABC) transporter ABCB1 in a drug-specific fashion. LP117, the compound that exerted the strongest effect on ABCB1, interfered in the investigated concentrations of up to 2μM with the ABCB1-mediated transport of vincristine, vinorelbine, actinomycin D, paclitaxel, and calcein-AM but not of doxorubicin, rhodamine 123, or JC-1. In silico docking studies identified differences in the interaction profiles of the investigated ABCB1 substrates with the known ABCB1 binding sites that may explain the substrate-specific effects of LP117. Thus, pirinixic acid derivatives may offer potential as drug-specific modulators of ABCB1-mediated drug transport. PMID:26887049

  20. Altered Cultivar Resistance of Kimchi Cabbage Seedlings Mediated by Salicylic Acid, Jasmonic Acid and Ethylene

    Young Hee Lee

    2014-09-01

    Full Text Available Two cultivars Buram-3-ho (susceptible and CR-Hagwang (moderate resistant of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum, black spot (Alternaria brassicicola and black rot (Xanthomonas campestris pv. campestris, Xcc diseases in our previous study. Defense-related hormones salicylic acid (SA, jasmonic acid (JA and ethylene led to different transcriptional regulation of pathogenesis-related (PR gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

  1. Mechanistic Modeling Reveals the Critical Knowledge Gaps in Bile Acid-Mediated DILI.

    Woodhead, J L; Yang, K; Brouwer, K L R; Siler, S Q; Stahl, S H; Ambroso, J L; Baker, D; Watkins, P B; Howell, B A

    2014-01-01

    Bile salt export pump (BSEP) inhibition has been proposed to be an important mechanism for drug-induced liver injury (DILI). Modeling can prioritize knowledge gaps concerning bile acid (BA) homeostasis and thus help guide experimentation. A submodel of BA homeostasis in rats and humans was constructed within DILIsym, a mechanistic model of DILI. In vivo experiments in rats with glibenclamide were conducted, and data from these experiments were used to validate the model. The behavior of DILIsym was analyzed in the presence of a simulated theoretical BSEP inhibitor. BSEP inhibition in humans is predicted to increase liver concentrations of conjugated chenodeoxycholic acid (CDCA) and sulfate-conjugated lithocholic acid (LCA) while the concentration of other liver BAs remains constant or decreases. On the basis of a sensitivity analysis, the most important unknowns are the level of BSEP expression, the amount of intestinal synthesis of LCA, and the magnitude of farnesoid-X nuclear receptor (FXR)-mediated regulation. PMID:25006780

  2. Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes.

    Maity, Ayan; Teets, Thomas S

    2016-08-10

    This Review highlights stoichiometric reactions and elementary steps of catalytic reactions involving cooperative participation of transition-metal hydrides and main group Lewis acids. Included are reactions where the transition-metal hydride acts as a reactant as well as transformations that form the metal hydride as a product. This Review is divided by reaction type, illustrating the diverse roles that Lewis acids can play in mediating transformations involving transition-metal hydrides as either reactants or products. We begin with a discussion of reactions where metal hydrides form direct adducts with Lewis acids, elaborating the structure and dynamics of the products of these reactions. The bulk of this Review focuses on reactions where the transition metal and Lewis acid act in cooperation, and includes sections on carbonyl reduction, H2 activation, and hydride elimination reactions, all of which can be promoted by Lewis acids. Also included is a section on Lewis acid-base secondary coordination sphere interactions, which can influence the reactivity of hydrides. Work from the past 50 years is included, but the majority of this Review focuses on research from the past decade, with the intent of showcasing the rapid emergence of this field and the potential for further development into the future. PMID:27164024

  3. Tumour–stromal interactions in acid-mediated invasion: A mathematical model

    Martin, Natasha K.

    2010-12-01

    It is well established that the tumour microenvironment can both promote and suppress tumour growth and invasion, however, most mathematical models of invasion view the normal tissue as inhibiting tumour progression via immune modulation or spatial constraint. In particular, the production of acid by tumour cells and the subsequent creation of a low extracellular pH environment has been explored in several \\'acid-mediated tumour invasion\\' models where the acidic environment facilitates normal cell death and permits tumour invasion. In this paper, we extend the acid-invasion model developed by Gatenby and Gawlinski (1996) to include both the competitive and cooperative interactions between tumour and normal cells, by incorporating the influence of extracellular matrix and protease production at the tumour-stroma interface. Our model predicts an optimal level of tumour acidity which produces both cell death and matrix degradation. Additionally, very aggressive tumours prevent protease production and matrix degradation by excessive normal cell destruction, leading to an acellular (but matrix filled) gap between the tumour and normal tissue, a feature seen in encapsulated tumours. These results suggest, counterintuitively, that increasing tumour acidity may, in some cases, prevent tumour invasion.

  4. Silver ion catalyzed cerium(IV) mediated electrochemical oxidation of phenol in nitric acid medium

    Mediated electrochemical oxidation (MEO) is one of the sustainable processes for organic pollutant destruction and has been employed for organic mineralization reactions by many researchers. In the MEO a metal ion capable of exhibiting redox behavior is oxidized from lower oxidation state to higher oxidation state by an electrochemical cell and subsequently used as an oxidant for mineralizing the toxic organics into CO2 and water. The net result is the consumption of electrical energy for organic mineralization. Therefore, the current efficiency is an important factor and maximizing the current efficiency is one of the ways of reducing the running cost of the MEO process. It has been reported in the literature that the current efficiency could be increased using a metal ion catalyst having a good redox potential. In this study Ce(IV) mediated electrochemical oxidation of phenol was carried out with silver ion catalyst. The current efficiency for the electro-oxidation of cerium(III) in nitric acid was found to be increased by the addition of silver ions. This mixed mediator system was tested for the oxidation of phenol in order to optimize the parameters for organic pollutant destruction. The mineralization efficiency calculated based on the CO2 evolution was found to be higher for silver catalyzed Ce(IV) mediated oxidation compared to the non-silver catalyzed system

  5. A conserved patch of hydrophobic amino acids modulates Myb activity by mediating protein-protein interactions.

    Dukare, Sandeep; Klempnauer, Karl-Heinz

    2016-07-01

    The transcription factor c-Myb plays a key role in the control of proliferation and differentiation in hematopoietic progenitor cells and has been implicated in the development of leukemia and certain non-hematopoietic tumors. c-Myb activity is highly dependent on the interaction with the coactivator p300 which is mediated by the transactivation domain of c-Myb and the KIX domain of p300. We have previously observed that conservative valine-to-isoleucine amino acid substitutions in a conserved stretch of hydrophobic amino acids have a profound effect on Myb activity. Here, we have explored the function of the hydrophobic region as a mediator of protein-protein interactions. We show that the hydrophobic region facilitates Myb self-interaction and binding of the histone acetyl transferase Tip60, a previously identified Myb interacting protein. We show that these interactions are affected by the valine-to-isoleucine amino acid substitutions and suppress Myb activity by interfering with the interaction of Myb and the KIX domain of p300. Taken together, our work identifies the hydrophobic region in the Myb transactivation domain as a binding site for homo- and heteromeric protein interactions and leads to a picture of the c-Myb transactivation domain as a composite protein binding region that facilitates interdependent protein-protein interactions of Myb with regulatory proteins. PMID:27080133

  6. Cellulose nanocrystals prepared via formic acid hydrolysis followed by TEMPO-mediated oxidation.

    Li, Bin; Xu, Wenyang; Kronlund, Dennis; Määttänen, Anni; Liu, Jun; Smått, Jan-Henrik; Peltonen, Jouko; Willför, Stefan; Mu, Xindong; Xu, Chunlin

    2015-11-20

    Cellulose nanocrystals (CNCs) as a renewable and biodegradable nanomaterial have wide application value. In this work, CNCs were extracted from bleached chemical pulp using two stages of isolation (i.e. formic acid (FA) hydrolysis and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) mediated oxidation) under mild conditions. In the first stage, FA was used to remove hemicellulose, swell cellulose fibers, and release CNCs. The FA could be readily recovered and reused. In the second stage, the CNCs isolated by FA were further modified by TEMPO-mediated oxidation to increase the surface charge of CNCs. It was found that the modified CNCs with more ordered crystal structure and higher surface charge had better redispersibility and higher viscosity in aqueous phase. Therefore, the modified CNCs could be more effective when used as rheology modifier in the fields of water based coating, paint, food etc. PMID:26344319

  7. Modulation of CpG oligodeoxynucleotide-mediated immune stimulation by locked nucleic acid (LNA)

    Vollmer, Jörg; Jepsen, Jan Stenvang; Uhlmann, Eugen; Schetter, Christian; Jurk, Marion; Wader, Tanja; Wüllner, Meike; Krieg, Arthur M; Stenvang, Jan

    2004-01-01

    Locked nucleic acid (LNA) is an RNA derivative that when introduced into oligodeoxynucleotides (ODN), mediates high efficacy and stability. CpG ODNs are potent immune stimulators and are recognized by toll-like receptor-9 (TLR9). Some phosphorothioate antisense ODNs bearing CpG dinucleotides have...... been shown to possess immune modulatory capacities. We investigated the effects of LNA substitutions on immune stimulation mediated by antisense ODN G3139 or CpG ODN 2006. LNA ODNs were tested for their ability to stimulate cytokine secretion from human immune cells or TLR9-dependent signaling....... Phosphorothioate chimeric LNA/DNA antisense ODNs with phosphodiester-linked LNA nucleobases at both ends showed a marked decrease of immune modulation with an increasing number of 3' and 5' LNA bases. In addition, guanosine-LNA and cytosine-LNA or simply cytosine-LNA substitutions in the CpG dinucleotides of ODN...

  8. The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes.

    Bensalah, Nasr; Dbira, Sondos; Bedoui, Ahmed

    2016-07-01

    In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond (BDD) anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in NaCl; however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and NaClO4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine (Cl2, HClO, ClO(-)) electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density (≤10mA/cm(2)) and neutral medium (pH in the range 6-9) should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate. PMID:27372125

  9. Reductive defluorination of perfluorooctanoic acid by hydrated electrons in a sulfite-mediated UV photochemical system

    Song, Zhou [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China); College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Tang, Heqing, E-mail: tangheqing@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China); Wang, Nan, E-mail: nwang83@sina.com [College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhu, Lihua [College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-11-15

    Highlights: • A new reductive method for PFOA defluorination was established by sulfite-mediated photolysis. • The defluorination of PFOA was dependent on sulfite concentration and solution pH. • A defluorination ratio of PFOA as high as 88.5% was achieved after reaction of 24 h. • A few of perfluorinated sulfonates were detected as intermediates during the degradation of PFOA. • A mechanism was proposed for the reductive defluorination of PFOA by hydrated electrons. -- Abstract: A method for reductive degradation of perfluorooctanoic acid (PFOA) was established by using a sulfite/UV process. This process led to a PFOA removal of 100% at about 1 h and a defluorination ratio of 88.5% at reaction time of 24 h under N{sub 2} atmosphere, whereas the use of either UV irradiation or SO{sub 3}{sup 2−} alone induced little defluorination of PFOA under the same conditions. It was confirmed that the reductive defluorination of PFOA was achieved by hydrated electrons being generated from the photo-conversion of SO{sub 3}{sup 2−} as a mediator. Theoretical reaction kinetic analysis demonstrated that the generation of hydrated electrons was promoted by increasing either SO{sub 3}{sup 2−} concentration or solution pH, leading to the acceleration of the PFOA defluorination. Accompanying the reduction of PFOA, a small amount of short-chain perfluorocarboxylic acids, less fluorinated carboxylic acids and perfluorinated alkyl sulfonates were generated, all of which were able to be further degraded with further releasing of fluoride ions. Based on the generation, accumulation and distribution of intermediates, hydrated electrons induced defluorination pathway of PFOA was proposed in a sulfite-mediated UV photochemical system.

  10. Efficient gene delivery system mediated by cis-aconitate-modified chitosan-g-stearic acid micelles

    Yao JJ

    2014-06-01

    Full Text Available Jing-Jing Yao, Yong-Zhong Du, Hong Yuan, Jian You, Fu-Qiang HuCollege of Pharmaceutical Sciences, Zhejiang University, Hangzhou, People’s Republic of ChinaAbstract: Cis-aconitate-modified chitosan-g-stearic acid (CA-CSO-SA micelles were ­synthesized in this study to improve the gene transfection efficiency of chitosan-g-stearic acid (CSO-SA. The CA-CSO-SA micelles had a similar size, critical micelle concentration, and ­morphology, but their zeta potential and cytotoxicity were reduced compared with CSO-SA micelles. After modification with cis-aconitate, the CA-CSO-SA micelles could also compact plasmid DNA (pDNA to form nanocomplexes. However, the DNA binding ability of CA-CSO-SA was slightly reduced compared with that of CSO-SA. The transfection efficiency mediated by CA-CSO-SA/pDNA against HEK-293 cells reached up to 37%, and was much higher than that of CSO-SA/pDNA (16%. Although the cis-aconitate modification reduced cellular uptake kinetics in the initial stages, the total amount of cellular uptake tended to be the same after 24 hours of incubation. An endocytosis inhibition experiment showed that the internalization mechanism of CA-CSO-SA/pDNA in HEK-293 cells was mainly via clathrin-mediated endocytosis, as well as caveolae-mediated endocytosis and macropinocytosis. Observation of intracellular trafficking indicated that the CSO-SA/pDNA complexes were trapped in endolysosomes, but CA-CSO-SA/pDNA was more widely distributed in the cytosol. This study suggests that modification with cis-aconitate improves the transfection efficiency of CSO-SA/pDNA.Keywords: chitosan-g-stearic acid, cis-aconitate, micelles, transfection efficiency, intracellular trafficking

  11. Reductive defluorination of perfluorooctanoic acid by hydrated electrons in a sulfite-mediated UV photochemical system

    Highlights: • A new reductive method for PFOA defluorination was established by sulfite-mediated photolysis. • The defluorination of PFOA was dependent on sulfite concentration and solution pH. • A defluorination ratio of PFOA as high as 88.5% was achieved after reaction of 24 h. • A few of perfluorinated sulfonates were detected as intermediates during the degradation of PFOA. • A mechanism was proposed for the reductive defluorination of PFOA by hydrated electrons. -- Abstract: A method for reductive degradation of perfluorooctanoic acid (PFOA) was established by using a sulfite/UV process. This process led to a PFOA removal of 100% at about 1 h and a defluorination ratio of 88.5% at reaction time of 24 h under N2 atmosphere, whereas the use of either UV irradiation or SO32− alone induced little defluorination of PFOA under the same conditions. It was confirmed that the reductive defluorination of PFOA was achieved by hydrated electrons being generated from the photo-conversion of SO32− as a mediator. Theoretical reaction kinetic analysis demonstrated that the generation of hydrated electrons was promoted by increasing either SO32− concentration or solution pH, leading to the acceleration of the PFOA defluorination. Accompanying the reduction of PFOA, a small amount of short-chain perfluorocarboxylic acids, less fluorinated carboxylic acids and perfluorinated alkyl sulfonates were generated, all of which were able to be further degraded with further releasing of fluoride ions. Based on the generation, accumulation and distribution of intermediates, hydrated electrons induced defluorination pathway of PFOA was proposed in a sulfite-mediated UV photochemical system

  12. Bile acid-induced arrhythmia is mediated by muscarinic M2 receptors in neonatal rat cardiomyocytes.

    Siti H Sheikh Abdul Kadir

    Full Text Available BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP is a common disease affecting up to 5% of pregnancies and which can cause fetal arrhythmia and sudden intrauterine death. We previously demonstrated that bile acid taurocholate (TC, which is raised in the bloodstream of ICP, can acutely alter the rate and rhythm of contraction and induce abnormal calcium destabilization in cultured neonatal rat cardiomyocytes (NRCM. Apart from their hepatic functions bile acids are ubiquitous signalling molecules with diverse systemic effects mediated by either the nuclear receptor FXR or by a recently discovered G-protein coupled receptor TGR5. We aim to investigate the mechanism of bile-acid induced arrhythmogenic effects in an in-vitro model of the fetal heart. METHODS AND RESULTS: Levels of bile acid transporters and nuclear receptor FXR were studied by quantitative real time PCR, western blot and immunostaining, which showed low levels of expression. We did not observe functional involvement of the canonical receptors FXR and TGR5. Instead, we found that TC binds to the muscarinic M(2 receptor in NRCM and serves as a partial agonist of this receptor in terms of inhibitory effect on intracellular cAMP and negative chronotropic response. Pharmacological inhibition and siRNA-knockdown of the M(2 receptor completely abolished the negative effect of TC on contraction, calcium transient amplitude and synchronisation in NRCM clusters. CONCLUSION: We conclude that in NRCM the TC-induced arrhythmia is mediated by the partial agonism at the M(2 receptor. This mechanism might serve as a promising new therapeutic target for fetal arrhythmia.

  13. Ezrin dephosphorylation/downregulation contributes to ursolic acid-mediated cell death in human leukemia cells

    Ezrin links the actin filaments with the cell membrane and has a functional role in the apoptotic process. It appears clear that ezrin is directly associated with Fas, leading to activation of caspase cascade and cell death. However, the exact role of ezrin in ursolic acid (UA)-induced apoptosis remains unclear. In this study, we show for the first time that UA induces apoptosis in both transformed and primary leukemia cells through dephosphorylation/downregulation of ezrin, association and polarized colocalization of Fas and ezrin, as well as formation of death-inducing signaling complex. These events are dependent on Rho-ROCK1 signaling pathway. Knockdown of ezrin enhanced cell death mediated by UA, whereas overexpression of ezrin attenuated UA-induced apoptosis. Our in vivo study also showed that UA-mediated inhibition of tumor growth of mouse leukemia xenograft model is in association with the dephosphorylation/downregulation of ezrin. Such findings suggest that the cytoskeletal protein ezrin may represent an attractive target for UA-mediated lethality in human leukemia cells

  14. Transcriptional Factors Mediating Retinoic Acid Signals in the Control of Energy Metabolism

    Rui Zhang

    2015-06-01

    Full Text Available Retinoic acid (RA, an active metabolite of vitamin A (VA, is important for many physiological processes including energy metabolism. This is mainly achieved through RA-regulated gene expression in metabolically active cells. RA regulates gene expression mainly through the activation of two subfamilies in the nuclear receptor superfamily, retinoic acid receptors (RARs and retinoid X receptors (RXRs. RAR/RXR heterodimers or RXR/RXR homodimers bind to RA response element in the promoters of RA target genes and regulate their expressions upon ligand binding. The development of metabolic diseases such as obesity and type 2 diabetes is often associated with profound changes in the expressions of genes involved in glucose and lipid metabolism in metabolically active cells. RA regulates some of these gene expressions. Recently, in vivo and in vitro studies have demonstrated that status and metabolism of VA regulate macronutrient metabolism. Some studies have shown that, in addition to RARs and RXRs, hepatocyte nuclear factor 4α, chicken ovalbumin upstream promoter-transcription factor II, and peroxisome proliferator activated receptor β/δ may function as transcriptional factors mediating RA response. Herein, we summarize current progresses regarding the VA metabolism and the role of nuclear receptors in mediating RA signals, with an emphasis on their implication in energy metabolism.

  15. What makes ribosome-mediated transcriptional attenuation sensitive to amino Acid limitation?

    2005-06-01

    Full Text Available Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal determines the expression of the amino acid biosynthetic operon (response. The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the

  16. What makes ribosome-mediated transcriptional attenuation sensitive to amino acid limitation?

    Johan Elf

    2005-06-01

    Full Text Available Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal determines the expression of the amino acid biosynthetic operon (response. The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the

  17. What makes ribosome-mediated transcriptional attenuation sensitive to amino acid limitation?

    Elf, Johan; Ehrenberg, Måns

    2005-06-01

    Ribosome-mediated transcriptional attenuation mechanisms are commonly used to control amino acid biosynthetic operons in bacteria. The mRNA leader of such an operon contains an open reading frame with "regulatory" codons, cognate to the amino acid that is synthesized by the enzymes encoded by the operon. When the amino acid is in short supply, translation of the regulatory codons is slow, which allows transcription to continue into the structural genes of the operon. When amino acid supply is in excess, translation of regulatory codons is rapid, which leads to termination of transcription. We use a discrete master equation approach to formulate a probabilistic model for the positioning of the RNA polymerase and the ribosome in the attenuator leader sequence. The model describes how the current rate of amino acid supply compared to the demand in protein synthesis (signal) determines the expression of the amino acid biosynthetic operon (response). The focus of our analysis is on the sensitivity of operon expression to a change in the amino acid supply. We show that attenuation of transcription can be hyper-sensitive for two main reasons. The first is that its response depends on the outcome of a race between two multi-step mechanisms with synchronized starts: transcription of the leader of the operon, and translation of its regulatory codons. The relative change in the probability that transcription is aborted (attenuated) can therefore be much larger than the relative change in the time it takes for the ribosome to read a regulatory codon. The second is that the general usage frequencies of codons of the type used in attenuation control are small. A small percentage decrease in the rate of supply of the controlled amino acid can therefore lead to a much larger percentage decrease in the rate of reading a regulatory codon. We show that high sensitivity further requires a particular choice of regulatory codon among several synonymous codons for the same amino acid. We

  18. Surface-Mediated Hydrogen Bonding of Proteinogenic α-Amino Acids on Silicon.

    Rahsepar, Fatemeh R; Moghimi, Nafiseh; Leung, K T

    2016-05-17

    Understanding the adsorption, film growth mechanisms, and hydrogen bonding interactions of biological molecules on semiconductor surfaces has attracted much recent attention because of their applications in biosensors, biocompatible materials, and biomolecule-based electronic devices. One of the most challenging questions when studying the behavior of biomolecules on a metal or semiconductor surface is "What are the driving forces and film growth mechanisms for biomolecular adsorption on these surfaces?" Despite a large volume of work on self-assembly of amino acids on single-crystal metal surfaces, semiconductor surfaces offer more direct surface-mediated interactions and processes with biomolecules. This is due to their directional surface dangling bonds that could significantly perturb hydrogen bonding arrangements. For all the proteinogenic biomolecules studied to date, our group has observed that they generally follow a "universal" three-stage growth process on Si(111)7×7 surface. This is supported by corroborating data obtained from a three-pronged approach of combining chemical-state information provided by X-ray photoelectron spectroscopy (XPS) and the site-specific local density-of-state images obtained by scanning tunneling microscopy (STM) with large-scale quantum mechanical modeling based on the density functional theory with van der Waals corrections (DFT-D2). Indeed, this three-stage growth process on the 7×7 surface has been observed for small benchmark biomolecules, including glycine (the simplest nonchiral amino acid), alanine (the simplest chiral amino acid), cysteine (the smallest amino acid with a thiol group), and glycylglycine (the smallest (di)peptide of glycine). Its universality is further validated here for the other sulfur-containing proteinogenic amino acid, methionine. We use methionine as an example of prototypical proteinogenic amino acids to illustrate this surface-mediated process. This type of growth begins with the formation of

  19. A family of conserved bacterial effectors inhibits salicylic acid-mediated basal immunity and promotes disease necrosis in plants

    DebRoy, Sruti; Thilmony, Roger; Kwack, Yong-Bum; Nomura, Kinya; He, Sheng Yang

    2004-01-01

    Salicylic acid (SA)-mediated host immunity plays a central role in combating microbial pathogens in plants. Inactivation of SA-mediated immunity, therefore, would be a critical step in the evolution of a successful plant pathogen. It is known that mutations in conserved effector loci (CEL) in the plant pathogens Pseudomonas syringae (the ΔCEL mutation), Erwinia amylovora (the dspA/E mutation), and Pantoea stewartii subsp. stewartii (the wtsE mutation) exert particularly strong negative effect...

  20. Tropodithietic Acid Production in Phaeobacter gallaeciensis Is Regulated by N-Acyl Homoserine Lactone-Mediated Quorum Sensing▿

    Berger, Martine; Neumann, Alexander; Schulz, Stefan; Simon, Meinhard; Brinkhoff, Thorsten

    2011-01-01

    The production of N-acyl homoserine lactones (AHLs) is widely distributed within the marine Roseobacter clade, and it was proposed that AHL-mediated quorum sensing (QS) is one of the most common cell-to-cell communication mechanisms in roseobacters. The traits regulated by AHL-mediated QS are yet not known for members of the Roseobacter clade, but production of the antibiotic tropodithietic acid (TDA) was supposed to be controlled by AHL-mediated QS in Phaeobacter spp. We describe here for th...

  1. Bile acid effects are mediated by ATP release and purinergic signalling in exocrine pancreatic cells

    Kowal, Justyna Magdalena; Haanes, Kristian Agmund; Christensen, Nynne;

    2015-01-01

    BACKGROUND: In many cells, bile acids (BAs) have a multitude of effects, some of which may be mediated by specific receptors such the TGR5 or FXR receptors. In pancreas systemic BAs, as well as intra-ductal BAs from bile reflux, can affect pancreatic secretion. Extracellular ATP and purinergic......) and duct cells (Capan-1). Taurine and glycine conjugated forms of CDCA had smaller effects on ATP release in Capan-1 cells. In duct monolayers, CDCA stimulated ATP release mainly from the luminal membrane; the releasing mechanisms involved both vesicular and non-vesicular secretion pathways. Duct...... cells were not depleted of intracellular ATP with CDCA, but acinar cells lost some ATP, as detected by several methods including ATP sensor AT1.03(YEMK). In duct cells, CDCA caused reversible increase in the intracellular Ca(2+) concentration [Ca(2 +)]i, which could be significantly inhibited by...

  2. Poly(methacrylic acid)-mediated morphosynthesis of PbWO4 micro-crystals

    PbWO4 crystals with various morphologies were fabricated via a facile poly(methacrylic acid)-mediated hydrothermal route. Novel microsized PbWO4 single crystals with a needle-like shape as well as other morphologies, such as a fishbone, dendrite, sphere, spindle, ellipsoid, rod, and dumbbell with two dandelion-like heads, could be produced. The presence of PMAA, [Pb2+]/[WO42-] molar ratio (R), and aging temperature played key roles in the formation of the PbWO4 needle-like structures. Between temperatures of 60 to 150 C, the length and photoluminescence intensities of the PbWO4 micro needles significantly increased with aging temperature, while the diameter did not change remarkably. Time-dependent experiments revealed that the formation of PbWO4 microneedles involved an unusual growth process, involving nucleation, oriented assembly and controlled mesoscale restructuring of nanoparticle building blocks. (orig.)

  3. Sm(II)-Mediated Electron Transfer to Carboxylic Acid Derivatives: Development of Complexity-Generating Cascades.

    Just-Baringo, Xavier; Procter, David J

    2015-05-19

    exploited productively in efficient new processes. First, we have used internal directing groups in substrates to "switch on" productive ET to esters and amides and have exploited such an approach in tag-removal cyclization processes that deliver molecular scaffolds of significance in biology and materials science. Second, we have exploited external ligands to facilitate ET to carboxylic acid derivatives and have applied the strategy in telescoped reaction sequences. Finally, we have employed follow-up cyclizations with alkenes, alkynes, and allenes to intercept radical anion intermediates formed along the reaction path and have employed this strategy in complexity-generating cascade approaches to biologically significant molecular architectures. From our studies, it is now clear that Sm(II)-mediated ET to carboxylic acid derivatives constitutes a general strategy for inverting the polarity of the carbonyl, allowing nucleophilic carbon-centered radicals to be formed and exploited in novel chemical processes. PMID:25871998

  4. Constitutive androstane receptor-mediated changes in bile acid composition contributes to hepatoprotection from lithocholic acid-induced liver injury in mice.

    Beilke, Lisa D; Aleksunes, Lauren M; Holland, Ricky D; Besselsen, David G; Beger, Rick D; Klaassen, Curtis D; Cherrington, Nathan J

    2009-05-01

    Pharmacological activation of the constitutive androstane receptor (CAR) protects the liver during cholestasis. The current study evaluates how activation of CAR influences genes involved in bile acid biosynthesis as a mechanism of hepatoprotection during bile acid-induced liver injury. CAR activators phenobarbital (PB) and 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) or corn oil (CO) were administered to C57BL/6 wild-type (WT) and CAR knockout (CAR-null) mice before and during induction of intrahepatic cholestasis using the secondary bile acid, lithocholic acid (LCA). In LCA-treated WT and all the CAR-null groups (excluding controls), histology revealed severe multifocal necrosis. This pathology was absent in WT mice pretreated with PB and TCPOBOP, indicating CAR-dependent hepatoprotection. Decreases in total hepatic bile acids and hepatic monohydroxy, dihydroxy, and trihydroxy bile acids in PB- and TCPOBOP-pretreated WT mice correlated with hepatoprotection. In comparison, concentrations of monohydroxylated and dihydroxylated bile acids were increased in all the treated CAR-null mice compared with CO controls. Along with several other enzymes (Cyp7b1, Cyp27a1, Cyp39a1), Cyp8b1 expression was increased in hepatoprotected mice, which could be suggestive of a shift in the bile acid biosynthesis pathway toward the formation of less toxic bile acids. In CAR-null mice, these changes in gene expression were not different among treatment groups. These results suggest CAR mediates a shift in bile acid biosynthesis toward the formation of less toxic bile acids, as well as a decrease in hepatic bile acid concentrations. We propose that these combined CAR-mediated effects may contribute to the hepatoprotection observed during LCA-induced liver injury. PMID:19196849

  5. Multivalent ion-mediated nucleic acid helix-helix interactions: RNA versus DNA

    Wu, Yuan-Yan; Zhang, Jin-Si; Zhu, Xiao-Long; Tan, Zhi-Jie

    2015-01-01

    Ion-mediated interaction is critical to the structure and stability of nucleic acids. Recent experiments suggest that the multivalent ion-induced aggregation of double-stranded (ds) RNAs and DNAs may strongly depend on the topological nature of helices, while there is still lack of an understanding on the relevant ion-mediated interactions at atomistic level. In this work, we have directly calculated the potentials of mean force (PMF) between two dsRNAs and between two dsDNAs in Cobalt Hexammine ion (Co-Hex) solutions by the atomistic molecular dynamics simulations. Our calculations show that at low [Co-Hex], the PMFs between B-DNAs and between A-RNAs are both (strongly) repulsive.However, at high [Co-Hex], the PMF between B-DNAs is strongly attractive, while those between A-RNAs and between A-DNAs are still (weakly) repulsive. The microscopic analyses show that for A-form helices, Co-Hex would become internal binding into the deep major groove and consequently cannot form the evident ion-bridge between adjac...

  6. Cullin-RING Ubiquitin Ligases in Salicylic Acid-Mediated Plant Immune Signaling

    James J. Furniss

    2015-03-01

    Full Text Available Plant immune responses against biotrophic pathogens are regulated by the signaling hormone salicylic acid (SA. SA establishes immunity by regulating a variety of cellular processes, including programmed cell death (PCD to isolate and kill invading pathogens, and development of systemic acquired resistance (SAR which provides long-lasting, broad-spectrum resistance throughout the plant. Central to these processes is post-translational modification of SA-regulated signaling proteins by ubiquitination, i.e. the covalent addition of small ubiquitin proteins. Emerging evidence indicates SA-induced protein ubiquitination is largely orchestrated by Cullin-RING ligases (CRLs, which recruit specific substrates for ubiquitination using interchangeable adaptors. Ligation of ubiquitin chains interlinked at lysine 48 leads to substrate degradation by the 26S proteasome. Here we discuss how CRL-mediated degradation of both nucleotide-binding/leucine-rich repeat domain containing (NLR immune receptors and SA-induced transcription regulators are critical for functional PCD and SAR responses, respectively. By placing these recent findings in context of knowledge gained in other eukaryotic model species, we highlight potential alternative roles for processive ubiquitination in regulating the activity of SA-mediated immune responses.

  7. Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling

    Sang-Keun Oh

    2014-09-01

    Full Text Available Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD. To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA, jasmonic acid (JA, and ethylene (ET in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

  8. Dehydroascorbic acid, a blood–brain barrier transportable form of vitamin C, mediates potent cerebroprotection in experimental stroke

    Huang, Judy; Agus, David B.; Winfree, Christopher J.; Kiss, Szilard; William J Mack; Ryan A McTaggart; Choudhri, Tanvir F.; Kim, Louis J.; Mocco, J; Pinsky, David J; Fox, William D.; Israel, Robert J.; Boyd, Thomas A.; Golde, David W.; Connolly, E Sander

    2001-01-01

    Neuronal injury in ischemic stroke is partly mediated by cytotoxic reactive oxygen species. Although the antioxidant ascorbic acid (AA) or vitamin C does not penetrate the blood–brain barrier (BBB), its oxidized form, dehydroascorbic acid (DHA), enters the brain by means of facilitative transport. We hypothesized that i.v. DHA would improve outcome after stroke because of its ability to cross the BBB and augment brain antioxidant levels. Reversible or permanent focal ...

  9. Excitatory amino acids may mediate nucleus tractus solitarius input to rat parabrachial neurons.

    Jhamandas, J H; Harris, K H

    1992-08-01

    The pontine parabrachial nucleus (PBN) is a recipient of predominantly excitatory input from the nucleus of the solitary tract (NTS). The presence of glutamate-like immunoreactivity at these brain stem sites suggests a role for excitatory amino acids (EAAs) in neurotransmission within the projection. We utilized electrophysiological studies in vivo to examine the ability of specific EAA antagonists, applied locally, to alter glutamate (GLU)-induced and NTS-evoked excitation of PBN neurons. Nonselective EAA antagonist kynurenic acid (KYN), the selective N-methyl-D-aspartate (NMDA) antagonist DL-2-amino-5-phosphonovalerate (APV), and non-NMDA quinoxalinedione group of blockers 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6-nitro-7-sulfamobenzoquinoxaline-2,3-dione (NBQX) were applied by iontophoresis or micropressure ejection from multibarreled pipettes attached to the recording electrode. Extracellular recordings in urethan-anesthetized rats were obtained from 58 PBN neurons that displayed an excitatory response following electrical stimulation within the NTS. Poststimulus histogram data revealed that NTS-evoked excitation could be reversibly blocked by KYN, APV, and CNQX in 21/37 (57%), 11/21 (52%), and 10/19 cells (53%), respectively. Both NMDA and non-NMDA antagonists reversibly attenuated or blocked GLU-evoked excitation in 21 of 29 PBN neurons. These observations suggest a role for both NMDA and non-NMDA receptors in mediating the excitatory input from NTS to the PBN. PMID:1354944

  10. K-channels inhibited by hydrogen peroxide mediate abscisic acid signaling in Vicia guard cells

    2001-01-01

    A number of studies show that environmental stress conditions increase abscisic acid (ABA) and hydrogen peroxide (H2O2) levels in plant cells. Despite this central role of ABA in altering stomatal aperture by regulating guard cell ion transport, little is known concerning the relationship between ABA and H2O2 in signal transduction leading to stomatal movement. Epidermal strip bioassay illustrated that ABA-inhibited stomatal opening and ABA-induced stomatal closure were abolished partly by externally added catalase (CAT) or diphenylene iodonium (DPI), which are a H2O2 scavenger and a NADPH oxidase inhibitor respectively. In contrast, internally added CAT or DPI nearly completely or partly reversed ABA-induced closure in half-stoma. Consistent with these results, whole-cell patch-clamp analysis showed that intracellular application of CAT or DPI partly abolished ABA-inhibited inward K+ current across the plasma membrane of guard cells. H2O2 mimicked ABA to inhibit inward K+ current, an effect which was reversed by the addition of ascorbic acid (Vc) in patch clamping micropipettes. These results suggested that H2O2 mediated ABA-induced stomatal movement by targeting inward K+ channels at plasma membrane.

  11. Theoretical Studies on the Isomerization of Peroxynitrite to Nitrate Mediated by Peroxynitrous Acid

    LIU Yong-Dong; ZHONG Ru-Gang

    2008-01-01

    The conversion of peroxynitrite(ONOO-)to nitrate(NO3-)mediated by peroxy-nitrous acid(ONOOH)has been investigated at the CCSD/6-311G(d)//B3L YP/6-311+G(d,P)level.Two kinds of pathways for the title reaction were found.The results show that the energy barrier ofisomerization through pathway 1 is around 25 kcal/mol in the gas phase.This value is significantly lower than that of isomerization without any catalysts.Thus,it indicates that ONOOH definitely makes the conversion from ONOO- to NO3- feasible.Although pathway 2 does not decrease the energy barrier of this isomerization,peroxynitric acid(O2NOOH)Was obtained;moreover,this is a new pathway for this formation.In view of the results that peroxynitrate anion Can decompose into nitrite and dioxygen.we conclude that our results are consistent with the experimental observation that nitrate,nitrite,and dioxygen are the main final products of the decay of peroxynitrite around pH7.

  12. Betulinic acid regulates generation of neuroinflammatory mediators responsible for tissue destruction in multiple sclerosis in vitro

    Blaževski, Jana; Petković, Filip; Momčilović, Miljana; Paschke, Reinhard; Kaluđerović, Goran N; Mostarica Stojković, Marija; Miljković, Djordje

    2013-01-01

    Aim: To investigate the influences of betulinic acid (BA), a triterpenoid isolated from birch bark, on neuroinflammatory mediators involved in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis in vitro. Methods: Encephalitogenic T cells were prepared from draining lymph nodes and spinal cords of Dark Agouti rats 8 to 10 d after immunization with myelin basic protein (MBP) and complete Freund's adjuvant. Macrophages were isolated from the peritoneal cavity of adult untreated rats. Astrocytes were isolated from neonatal rat brains. The cells were cultured and then treated with different agents. IFN-γ, IL-17, iNOS and CXCL12 mRNA levels in the cells were analyzed with RT-PCR. iNOS and CXCL12 protein levels were detected using immunoblot. NO and ROS generation was measured using Griess reaction and flow cytometry, respectively. Results: In encephalitogenic T cells stimulated with MBP (10 μg/mL), addition of BA inhibited IL-17 and IFN-γ production in a dose-dependent manner. The estimated IC50 values for IL-17 and IFN γ were 11.2 and 63.8 μmol/L, respectively. When the macrophages were stimulated with LPS (10 ng/mL), addition of BA (50 μmol/L) significantly increased ROS generation, and suppressed NO generation. The astrocytes were stimulated with ConASn containing numerous inflammatory mediators, which mimicked the inflammatory milieu within CNS; addition of BA (50 μmol/L) significantly increased ROS generation, and blocked ConASn-induced increases in iNOS and CXCL12 mRNA levels, but did not affect iNOS and CXCL12 protein levels. Importantly, in both the macrophages and astrocytes, addition of BA (50 μmol/L) inhibited lipid peroxidation. Conclusion: Besides inhibiting encephalitogenic T cell cytokines and reducing NO generation, BA induces tissue-damaging ROS generation within CNS. PMID:23377550

  13. Mechanisms of lysophosphatidic acid (LPA) mediated stimulation of intestinal apical Cl-/OH- exchange.

    Singla, Amika; Dwivedi, Alka; Saksena, Seema; Gill, Ravinder K; Alrefai, Waddah A; Ramaswamy, Krishnamurthy; Dudeja, Pradeep K

    2010-02-01

    Lysophosphatidic acid (LPA), a potent bioactive phospholipid, is a natural component of food products like soy and egg yolk. LPA modulates a number of epithelial functions and has been shown to inhibit cholera toxin-induced diarrhea. Antidiarrheal effects of LPA are known to be mediated by inhibiting chloride secretion. However, the effects of LPA on chloride absorption in the mammalian intestine are not known. The present studies examined the effects of LPA on apical Cl(-)/OH(-) exchangers known to be involved in chloride absorption in intestinal epithelial cells. Caco-2 cells were treated with LPA, and Cl(-)/OH(-) exchange activity was measured as DIDS-sensitive (36)Cl(-) uptake. Cell surface biotinylation studies were performed to evaluate the effect of LPA on cell surface levels of apical Cl(-)/OH(-) exchangers, downregulated in adenoma (DRA) (SLC26A3), and putative anion transporter-1 (SLC26A6). Treatment of Caco-2 cells with LPA (100 muM) significantly stimulated Cl(-)/OH(-) exchange activity. Specific agonist for LPA2 receptor mimicked the effects of LPA. LPA-mediated stimulation of Cl(-)/OH(-) exchange activity was dependent on activation of phosphatidylinositol 3-kinase/Akt signaling pathway. Consistent with the functional activity, LPA treatment resulted in increased levels of DRA on the apical membrane. Our results demonstrate that LPA stimulates apical Cl(-)/OH(-) exchange activity and surface levels of DRA in intestinal epithelial cells. This increase in Cl(-)/OH(-) exchange may contribute to the antidiarrheal effects of LPA. PMID:19910524

  14. Free radical mediated formation of 3-monochloropropanediol (3-MCPD) fatty acid diesters.

    Zhang, Xiaowei; Gao, Boyan; Qin, Fang; Shi, Haiming; Jiang, Yuangrong; Xu, Xuebing; Yu, Liangli Lucy

    2013-03-13

    The present study was conducted to test the hypothesis that a free radical was formed and mediated the formation of 3-monochloropropanediol (3-MCPD) fatty acid diesters, a group of food contaminants, from diacylglycerols at high temperature under a low-moisture condition for the first time. The presence of free radicals in a vegetable oil kept at 120 °C for 20 min was demonstrated using an electron spin resonance (ESR) spectroscopy examination with 5,5-dimethylpyrroline-N-oxide (DMPO) as the spin trap agent. ESR investigation also showed an association between thermal treatment degree and the concentration of free radicals. A Fourier transform infrared spectroscopy (FT-IR) analysis of sn-1,2-stearoylglycerol (DSG) at 25 and 120 °C suggested the possible involvement of an ester carbonyl group in forming 3-MCPD diesters. On the basis of these results, a novel free radical mediated chemical mechanism was proposed for 3-MCPD diester formation. Furthermore, a quadrupole-time of flight (Q-TOF) MS/MS investigation was performed and detected the DMPO adducts with the cyclic acyloxonium free radical (CAFR) and its product MS ions, proving the presence of CAFR. Furthermore, the free radical mechanism was validated by the formation of 3-MCPD diesters through reacting DSG with a number of organic and inorganic chlorine sources including chlorine gas at 120 and 240 °C. The findings of this study might lead to the improvement of oil and food processing conditions to reduce the level of 3-MCPD diesters in foods and enhance food safety. PMID:23425600

  15. Sialic Acid on the Glycosylphosphatidylinositol Anchor Regulates PrP-mediated Cell Signaling and Prion Formation.

    Bate, Clive; Nolan, William; Williams, Alun

    2016-01-01

    The prion diseases occur following the conversion of the cellular prion protein (PrP(C)) into disease-related isoforms (PrP(Sc)). In this study, the role of the glycosylphosphatidylinositol (GPI) anchor attached to PrP(C) in prion formation was examined using a cell painting technique. PrP(Sc) formation in two prion-infected neuronal cell lines (ScGT1 and ScN2a cells) and in scrapie-infected primary cortical neurons was increased following the introduction of PrP(C). In contrast, PrP(C) containing a GPI anchor from which the sialic acid had been removed (desialylated PrP(C)) was not converted to PrP(Sc). Furthermore, the presence of desialylated PrP(C) inhibited the production of PrP(Sc) within prion-infected cortical neurons and ScGT1 and ScN2a cells. The membrane rafts surrounding desialylated PrP(C) contained greater amounts of sialylated gangliosides and cholesterol than membrane rafts surrounding PrP(C). Desialylated PrP(C) was less sensitive to cholesterol depletion than PrP(C) and was not released from cells by treatment with glimepiride. The presence of desialylated PrP(C) in neurons caused the dissociation of cytoplasmic phospholipase A2 from PrP-containing membrane rafts and reduced the activation of cytoplasmic phospholipase A2. These findings show that the sialic acid moiety of the GPI attached to PrP(C) modifies local membrane microenvironments that are important in PrP-mediated cell signaling and PrP(Sc) formation. These results suggest that pharmacological modification of GPI glycosylation might constitute a novel therapeutic approach to prion diseases. PMID:26553874

  16. A potential plant-derived antifungal acetylenic acid mediates its activity by interfering with fatty acid homeostasis

    6-Nonadecynoic acid (6-NDA), a plant-derived acetylenic acid, exhibits strong inhibitory activity against the human fungal pathogens Candida albicans, Aspergillus fumigatus, and Trichophyton mentagrophytes. In the present study, transcriptional profiling coupled with mutant and biochemical analyses...

  17. Lysophosphatidic acid mediates myeloid differentiation within the human bone marrow microenvironment.

    Denis Evseenko

    Full Text Available Lysophosphatidic acid (LPA is a pleiotropic phospholipid present in the blood and certain tissues at high concentrations; its diverse effects are mediated through differential, tissue specific expression of LPA receptors. Our goal was to determine if LPA exerts lineage-specific effects during normal human hematopoiesis. In vitro stimulation of CD34+ human hematopoietic progenitors by LPA induced myeloid differentiation but had no effect on lymphoid differentiation. LPA receptors were expressed at significantly higher levels on Common Myeloid Progenitors (CMP than either multipotent Hematopoietic Stem/Progenitor Cells (HSPC or Common Lymphoid Progenitors (CLP suggesting that LPA acts on committed myeloid progenitors. Functional studies demonstrated that LPA enhanced migration, induced cell proliferation and reduced apoptosis of isolated CMP, but had no effect on either HSPC or CLP. Analysis of adult and fetal human bone marrow sections showed that PPAP2A, (the enzyme which degrades LPA was highly expressed in the osteoblastic niche but not in the perivascular regions, whereas Autotaxin (the enzyme that synthesizes LPA was expressed in perivascular regions of the marrow. We propose that a gradient of LPA with the highest levels in peri-sinusoidal regions and lowest near the endosteal zone, regulates the localization, proliferation and differentiation of myeloid progenitors within the bone marrow marrow.

  18. The Salicylic Acid-Mediated Release of Plant Volatiles Affects the Host Choice of Bemisia tabaci.

    Shi, Xiaobin; Chen, Gong; Tian, Lixia; Peng, Zhengke; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Zhou, Xuguo; Zhang, Youjun

    2016-01-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes serious crop losses worldwide by transmitting viruses. We have previously shown that salicylic acid (SA)-related plant defenses directly affect whiteflies. In this study, we applied exogenous SA to tomato plants in order to investigate the interaction between SA-induced plant volatiles and nonviruliferous B. tabaci B and Q or B- and Q-carrying tomato yellow leaf curl virus (TYLCV). The results showed that exogenous SA caused plants to repel nonviruliferous whiteflies, but the effect was reduced when the SA concentration was low and when the whiteflies were viruliferous. Exogenous SA increased the number and quantity of plant volatiles-especially the quantity of methyl salicylate and δ-limonene. In Y-tube olfactometer assays, methyl salicylate and δ-limonene repelled the whiteflies, but the repellency was reduced for viruliferous Q. We suggest that the release of plant volatiles as mediated by SA affects the interaction between whiteflies, plants, and viruses. Further studies are needed to determine why viruliferous Q is less sensitive than nonviruliferous Q to repellent plant volatiles. PMID:27376280

  19. NPM and BRG1 Mediate Transcriptional Resistance to Retinoic Acid in Acute Promyelocytic Leukemia.

    Nichol, Jessica N; Galbraith, Matthew D; Kleinman, Claudia L; Espinosa, Joaquín M; Miller, Wilson H

    2016-03-29

    Perturbation in the transcriptional control of genes driving differentiation is an established paradigm whereby oncogenic fusion proteins promote leukemia. From a retinoic acid (RA)-sensitive acute promyelocytic leukemia (APL) cell line, we derived an RA-resistant clone characterized by a block in transcription initiation, despite maintaining wild-type PML/RARA expression. We uncovered an aberrant interaction among PML/RARA, nucleophosmin (NPM), and topoisomerase II beta (TOP2B). Surprisingly, RA stimulation in these cells results in enhanced chromatin association of the nucleosome remodeler BRG1. Inhibition of NPM or TOP2B abrogated BRG1 recruitment. Furthermore, NPM inhibition and targeting BRG1 restored differentiation when combined with RA. Here, we demonstrate a role for NPM and BRG1 in obstructing RA differentiation and implicate chromatin remodeling in mediating therapeutic resistance in malignancies. NPM mutations are the most common genetic change in patients with acute leukemia (AML); therefore, our model may be applicable to other more common leukemias driven by NPM. PMID:26997274

  20. Fe3O4/salicylic acid nanoparticles versatility in magnetic mediated vascular nanoblockage

    An aqueous dispersion of Fe3O4/salicylic acid magnetic nanoparticles (SaMNPs) was synthesized by a modified Massart method, characterized by Inductively Coupled Plasma–Optic Emission Spectrometry (ICP-OES), High-Resolution Transmission Electron Microscopy (HRTEM) and Dynamic Light Scattering (DLS) methods, and tested on the chick chorioallantoic membrane (CAM) model to evaluate biocompatibility, biodistribution, intravascular time persistence, and ability to be magnetically target driven in order to block the blood supply into a tumor xenograft. ICP-OES, DLS, and HRTEM SaMNPs sample analyses showed a 0.356 mg/mL Fe concentration, a good stability in water (average Zeta potential of 39.3 mV), a hydrodynamic diameter around 52 nm and a core diameter in the 7–15 nm range for the Fe3O4 nanoparticles. In vivo CAM assay showed that SaMNPs were biocompatible with the chick embryo, were fixed almost completely by the liver, had no embolic potential, and a threshold-dose-dependent intravascular magnetic targeting time. Study on the CAM tumor model showed that SaMNPs could be used for long-term magnetically mediated nanoblocking of the capillary networks and 70-µm smaller arterioles

  1. Poly(methacrylic acid)-mediated morphosynthesis of PbWO{sub 4} micro-crystals

    Yu, J.G.; Zhao, X.F.; Liu, S.W. [Wuhan University of Technology, State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan (China); Li, M.; Mann, S. [University of Bristol, School of Chemistry, Bristol (United Kingdom); Ng, D.H.L. [The Chinese University of Hong Kong, Department of Physics, Hong Kong (China)

    2007-04-15

    PbWO{sub 4} crystals with various morphologies were fabricated via a facile poly(methacrylic acid)-mediated hydrothermal route. Novel microsized PbWO{sub 4} single crystals with a needle-like shape as well as other morphologies, such as a fishbone, dendrite, sphere, spindle, ellipsoid, rod, and dumbbell with two dandelion-like heads, could be produced. The presence of PMAA, [Pb{sup 2+}]/[WO{sub 4} {sup 2-}] molar ratio (R), and aging temperature played key roles in the formation of the PbWO{sub 4} needle-like structures. Between temperatures of 60 to 150 C, the length and photoluminescence intensities of the PbWO{sub 4} micro needles significantly increased with aging temperature, while the diameter did not change remarkably. Time-dependent experiments revealed that the formation of PbWO{sub 4} microneedles involved an unusual growth process, involving nucleation, oriented assembly and controlled mesoscale restructuring of nanoparticle building blocks. (orig.)

  2. Nonlinear stability of a heterogeneous state in a PDE-ODE model for acid-mediated tumor invasion.

    Tao, Youshan; Tello, J Ignacio

    2016-02-01

    This work studies a general reaction-diffusion model for acid-mediated tumor invasion, where tumor cells produce excess acid that primarily kills healthy cells, and thereby invade the microenvironment. The acid diffuses and could be cleared by vasculature, and the healthy and tumor cells are viewed as two species following logistic growth with mutual competition. A key feature of this model is the density-limited diffusion for tumor cells, reflecting that a healthy tissue will spatially constrain a tumor unless shrunk. Under appropriate assumptions on model parameters and on initial data, it is shown that the unique heterogeneous state is nonlinearly stable, which implies a long-term coexistence of the healthy and tumor cells in certain parameter space. Our theoretical result suggests that acidity may play a significant role in heterogeneous tumor progression. PMID:26776259

  3. Phenolic Acid-Mediated Regulation of the padC Gene, Encoding the Phenolic Acid Decarboxylase of Bacillus subtilis▿ †

    Tran, Ngoc Phuong; Gury, Jerôme; Dartois, Véronique; Nguyen, Thi Kim Chi; Seraut, Hélène; Barthelmebs, Lise; Gervais, Patrick; Cavin, Jean-François

    2008-01-01

    In Bacillus subtilis, several phenolic acids specifically induce expression of padC, encoding a phenolic acid decarboxylase that converts these antimicrobial compounds into vinyl derivatives. padC forms an operon with a putative coding sequence of unknown function, yveFG, and this coding sequence does not appear to be involved in the phenolic acid stress response (PASR). To identify putative regulators involved in the PASR, random transposon mutagenesis, combined with two different screens, w...

  4. Studies on low energy ion beam mediated DNA transformation of 2-keto-L-gulonic acid strains

    The biological effect of 2-keto-L-gulonic acid strains and their DNA implanted by low energy ions have been studied. Through low energy ion beam-mediated transferring foreign DNA into 2-KLG strain, two gene recombination strains were obtained. From this, a new research system-delivery of foreign DNA into microorganism via ion beam was established, offering a new way to construct genetically engineered microorganism. (authors)

  5. Inhibition of bleomycin-induced pulmonary fibrosis by nordihydroguaiaretic acid. The role of alveolar macrophage activation and mediator production.

    Phan, S. H.; Kunkel, S L

    1986-01-01

    The role of alveolar macrophage activation and release of mediators remains unclear. In this study, this role is examined with respect to the effects of relatively selective inhibitors of arachidonate metabolism on the pathogenesis of pulmonary fibrosis. CBA/J mice were administered bleomycin (0.037 units) endotracheally to induce pulmonary fibrosis. Daily intraperitoneal injections of a lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA) inhibited pulmonary fibrosis in a dose-dependent ...

  6. ASXL1 Represses Retinoic Acid Receptor-mediated Transcription through Associating with HP1 and LSD1*

    Lee, Sang-Wang; Cho, Yang-Sook; Na, Jung-Min; Park, Ui-Hyun; Kang, Myengmo; Kim, Eun-Joo; Um, Soo-Jong

    2009-01-01

    We previously suggested that ASXL1 (additional sex comb-like 1) functions as either a coactivator or corepressor for the retinoid receptors retinoic acid receptor (RAR) and retinoid X receptor in a cell type-specific manner. Here, we provide clues toward the mechanism underlying ASXL1-mediated repression. Transfection assays in HEK293 or H1299 cells indicated that ASXL1 alone possessing autonomous transcriptional repression activity significantly represses RAR- or retinoid X receptor-dependen...

  7. TRIM32 promotes retinoic acid receptor α-mediated differentiation in human promyelogenous leukemic cell line HL60

    Highlights: ► TRIM32 enhanced RARα-mediated transcriptional activity even in the absence of RA. ► TRIM32 stabilized RARα in the human promyelogenous leukemic cell line HL60. ► Overexpression of TRIM32 in HL60 cells induced granulocytic differentiation. ► TRIM32 may function as a coactivator for RARα-mediated transcription in APL cells. -- Abstract: Ubiquitination, one of the posttranslational modifications, appears to be involved in the transcriptional activity of nuclear receptors including retinoic acid receptor α (RARα). We previously reported that an E3 ubiquitin ligase, TRIM32, interacts with several important proteins including RARα and enhances transcriptional activity of RARα in mouse neuroblastoma cells and embryonal carcinoma cells. Retinoic acid (RA), which acts as a ligand to nuclear receptors including RARα, plays crucial roles in development, differentiation, cell cycles and apoptosis. In this study, we found that TRIM32 enhances RARα-mediated transcriptional activity even in the absence of RA and stabilizes RARα in the human promyelogenous leukemic cell line HL60. Moreover, we found that overexpression of TRIM32 in HL60 cells suppresses cellular proliferation and induces granulocytic differentiation even in the absence of RA. These findings suggest that TRIM32 functions as one of the coactivators for RARα-mediated transcription in acute promyelogenous leukemia (APL) cells, and thus TRIM32 may become a potentially therapeutic target for APL.

  8. β-aminobutyric acid mediated drought stress alleviation in maize (Zea mays L.).

    Shaw, Arun K; Bhardwaj, Pardeep K; Ghosh, Supriya; Roy, Sankhajit; Saha, Suman; Sherpa, Ang R; Saha, Samir K; Hossain, Zahed

    2016-02-01

    The present study highlights the role of β-aminobutyric acid (BABA) in alleviating drought stress effects in maize (Zea mays L.). Chemical priming was imposed by pretreating 1-week-old plants with 600 μM BABA prior to applying drought stress. Specific activities of key antioxidant enzymes and metabolites (ascorbate and glutathione) levels of ascorbate-glutathione cycle were studied to unravel the priming-induced modulation of plant defense system. Furthermore, changes in endogenous ABA and JA concentrations as well as mRNA expressions of key genes involved in their respective biosynthesis pathways were monitored in BABA-primed (BABA+) and non-primed (BABA-) leaves of drought-challenged plants to better understand the mechanistic insights into the BABA-induced hormonal regulation of plant response to water-deficit stress. Accelerated stomatal closure, high relative water content, and less membrane damage were observed in BABA-primed leaves under water-deficit condition. Elevated APX and SOD activity in non-primed leaves found to be insufficient to scavenge all H2O2 and O2 (·-) resulting in oxidative burst as evident after histochemical staining with NBT and DAB. A higher proline accumulation in non-primed leaves also does not give much protection against drought stress. Increased GR activity supported with the enhanced mRNA and protein expressions might help the BABA-primed plants to maintain a high GSH pool essential for sustaining balanced redox status to counter drought-induced oxidative stress damages. Hormonal analysis suggests that in maize, BABA-potentiated drought tolerance is primarily mediated through JA-dependent pathway by the activation of antioxidant defense systems while ABA biosynthesis pathway also plays an important role in fine-tuning of drought stress response. PMID:26416125

  9. Mixed Phenolic Acids Mediated Proliferation of Pathogens Talaromyces helicus and Kosakonia sacchari in Continuously Monocultured Radix pseudostellariae Rhizosphere Soil.

    Wu, Hongmiao; Wu, Linkun; Wang, Juanying; Zhu, Quan; Lin, Sheng; Xu, Jiahui; Zheng, Cailiang; Chen, Jun; Qin, Xianjin; Fang, Changxun; Zhang, Zhixing; Azeem, Saadia; Lin, Wenxiong

    2016-01-01

    Radix pseudostellariae L. is a common and popular Chinese medication. However, continuous monoculture has increased its susceptibility to severe diseases. We identified two pathogenic microorganisms, Talaromyces helicus M. (KU355274) and Kosakonia sacchari W. (KU324465), and their antagonistic bacterium, Bacillus pumilus Z. in rhizosphere soil of continuously monocultured R. pseudostellariae. Nine types of phenolic acids were identified both in the rhizosphere soil and in culture medium under sterile conditions. A syringic acid and phenolic acid mixture significantly promoted the growth of T. helicus and K. sacchari. T. helicus could utilize eight types of phenolic acids, whereas K. sacchari could only use four phenolic acids. K. sacchari produced protocatechuic acid when consuming vanillin. Protocatechuic acid negatively affected the growth of B. pumilus. The 3A-DON toxin produced by T. helicus promoted the growth of K. sacchari and inhibited growth of B. pumilus at low concentrations. These data help explain why phenolic exudates mediate a microflora shift and structure disorder in the rhizosphere soil of continuously monocultured R. pseudostellariae and lead to increased replanting disease incidence. PMID:27014250

  10. Mixed phenolic acids mediated proliferation of pathogens Talaromyces helicus and Kosakonia sacchari in continuously monocultured Radix pseudostellariae rhizosphere soil

    Hongmiao eWu

    2016-03-01

    Full Text Available Radix pseudostellariae L. is a common and popular Chinese medication. However, continuous monoculture has increased its susceptibility to severe diseases. We identified two pathogenic microorganisms, Talaromyces helicus M. (KU355274 and Kosakonia sacchari W. (KU324465, and their antagonistic bacterium, Bacillus pumilus Z. in rhizosphere soil of continuously monocultured R. pseudostellariae. Nine types of phenolic acids were identified both in the rhizosphere soil and in culture medium under sterile conditions. A syringic acid and phenolic acid mixture significantly promoted the growth of T. helicus and K. sacchari. T. helicus could utilize eight types of phenolic acids, whereas K. sacchari could only use four phenolic acids. K. sacchari produced protocatechuic acid when consuming vanillin. Protocatechuic acid negatively affected the growth of B. pumilus. The 3A-DON toxin produced by T. helicus promoted the growth of K. sacchari and inhibited growth of B. pumilus at low concentrations. These data help explain why phenolic exudates mediate a microflora shift and structure disorder in the rhizosphere soil of continuously monocultured R. pseudostellariae and lead to increased replanting disease incidence.

  11. Phospholipase C and diacylglycerol mediate olfactory responses to amino acids in the main olfactory epithelium of an amphibian.

    Sansone, Alfredo; Hassenklöver, Thomas; Syed, Adnan S; Korsching, Sigrun I; Manzini, Ivan

    2014-01-01

    The semi-aquatic lifestyle of amphibians represents a unique opportunity to study the molecular driving forces involved in the transition of aquatic to terrestrial olfaction in vertebrates. Most amphibians have anatomically segregated main and vomeronasal olfactory systems, but at the cellular and molecular level the segregation differs from that found in mammals. We have recently shown that amino acid responses in the main olfactory epithelium (MOE) of larval Xenopus laevis segregate into a lateral and a medial processing stream, and that the former is part of a vomeronasal type 2 receptor expression zone in the MOE. We hypothesized that the lateral amino acid responses might be mediated via a vomeronasal-like transduction machinery. Here we report that amino acid-responsive receptor neurons in the lateral MOE employ a phospholipase C (PLC) and diacylglycerol-mediated transduction cascade that is independent of Ca(2+) store depletion. Furthermore, we found that putative transient receptor potential (TRP) channel blockers inhibit most amino acid-evoked responses in the lateral MOE, suggesting that ion channels belonging to the TRP family may be involved in the signaling pathway. Our data show, for the first time, a widespread PLC- and diacylglycerol-dependent transduction cascade in the MOE of a vertebrate already possessing a vomeronasal organ. PMID:24489954

  12. Phospholipase C and diacylglycerol mediate olfactory responses to amino acids in the main olfactory epithelium of an amphibian.

    Alfredo Sansone

    Full Text Available The semi-aquatic lifestyle of amphibians represents a unique opportunity to study the molecular driving forces involved in the transition of aquatic to terrestrial olfaction in vertebrates. Most amphibians have anatomically segregated main and vomeronasal olfactory systems, but at the cellular and molecular level the segregation differs from that found in mammals. We have recently shown that amino acid responses in the main olfactory epithelium (MOE of larval Xenopus laevis segregate into a lateral and a medial processing stream, and that the former is part of a vomeronasal type 2 receptor expression zone in the MOE. We hypothesized that the lateral amino acid responses might be mediated via a vomeronasal-like transduction machinery. Here we report that amino acid-responsive receptor neurons in the lateral MOE employ a phospholipase C (PLC and diacylglycerol-mediated transduction cascade that is independent of Ca(2+ store depletion. Furthermore, we found that putative transient receptor potential (TRP channel blockers inhibit most amino acid-evoked responses in the lateral MOE, suggesting that ion channels belonging to the TRP family may be involved in the signaling pathway. Our data show, for the first time, a widespread PLC- and diacylglycerol-dependent transduction cascade in the MOE of a vertebrate already possessing a vomeronasal organ.

  13. Antagonism between abscisic acid and gibberellins is partially mediated by ascorbic acid during seed germination in rice

    Ye, Nenghui; Zhang, Jianhua

    2012-01-01

    The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination,1,2 but the mechanism of antagonism during this process is not known. In the associated study,3 we investigated the relationship among ABA, reactive oxygen species (ROS), ascorbic acid (ASC) and GA during rice seed germination. ROS production is reduced by ABA, which hence results in decreasing ASC accumulation during imbibition. GA accumulation was also suppressed by a reduced ROS...

  14. Multi-functionalized hyaluronic acid nanogels crosslinked with carbon dots as dual receptor-mediated targeting tumor theranostics.

    Jia, Xu; Han, Yu; Pei, Mingliang; Zhao, Xubo; Tian, Kun; Zhou, Tingting; Liu, Peng

    2016-11-01

    Hyaluronic acid (HA)-based theranostic nanogels were designed for the tumor diagnosis and chemotherapy, by crosslinking the folate-terminated poly(ethylene glycol) modified hyaluronic acid (FA-PEG-HA) with carbon dots (CDs) for the first time. Due to the extraordinary fluorescence property of the integrated CDs, the theranostic nanogels could be used for the real-time and noninvasive location tracking to cancer cells. HA could load Doxorubicin (DOX) via electrostatic interaction with a drug-loading capacity (DLC) of 32.5%. The nanogels possessed an ideal release of DOX in the weak acid environment, while it was restrained in the neutral media, demonstrating the pH-responsive controlled release behavior. The cytotoxicity and cellular uptake results clearly illustrated that most DOX was released and accumulated in the cell nuclei and killed the cancer cells efficaciously, due to their dual receptor-mediated targeting characteristics. PMID:27516286

  15. Cinnamic Acid and Its Derivatives Inhibit Fructose-Mediated Protein Glycation

    Sirintorn Yibchok-anun; Sirichai Adisakwattana; Weerachat Sompong; Sathaporn Ngamukote; Aramsri Meeprom

    2012-01-01

    Cinnamic acid and its derivatives have shown a variety of pharmacologic properties. However, little is known about the antiglycation properties of cinnamic acid and its derivatives. The present study sought to characterize the protein glycation inhibitory activity of cinnamic acid and its derivatives in a bovine serum albumin (BSA)/fructose system. The results demonstrated that cinnamic acid and its derivatives significantly inhibited the formation of advanced glycation end products (AGEs) by...

  16. Thyroid hormone receptor can modulate retinoic acid-mediated axis formation in frog embryogenesis.

    Banker, D E; Eisenman, R N

    1993-01-01

    Thyroid hormone receptor acts as a hormone-dependent transcriptional transactivator and as a transcriptional repressor in the absence of thyroid hormone. Specifically, thyroid hormone receptor can repress retinoic acid-induced gene expression through interactions with retinoic acid receptor. (Retinoic acid is a potent teratogen in the frog Xenopus laevis, acting at early embryonic stages to interfere with the formation of anterior structures. Endogenous retinoic acid is thought to act in norm...

  17. Mediation of Staphylococcus saprophyticus adherence to uroepithelial cells by lipoteichoic acid.

    Teti, G; Chiofalo, M S; Tomasello, F.; Fava, C.; Mastroeni, P.

    1987-01-01

    Treatment of uroepithelial cells with lipoteichoic acid from Staphylococcus saprophyticus resulted in a decrease in the adherence of this organism. Similar effects were observed when bacteria were pretreated with the lipoteichoic acid ligands albumin and anti-polyglycerophosphate monoclonal antibodies. Lipoteichoic acid might behave as an adhesin of S. saprophyticus.

  18. Effects of 5-aminolevulinic acid-mediated sonodynamic therapy on macrophages

    Cheng J

    2013-02-01

    Full Text Available Jiali Cheng,1,* Xin Sun,1,2,* Shuyuan Guo,1,* Wei Cao,1 Haibo Chen,1 Yinghua Jin,1 Bo Li,1 Qiannan Li,1 Huan Wang,1 Zhu Wang,3 Qi Zhou,3 Peng Wang,3 Zhiguo Zhang,3 Wenwu Cao,3,4 Ye Tian1,21Division of Cardiology, the First Affiliated Hospital, Cardiovascular Institute, Harbin Medical University, Harbin, People’s Republic of China; 2Division of Pathophysiology, the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Harbin, People’s Republic of China; 3Laboratory of Photo- and Sono-theranostic Technologies and Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin, People’s Republic of China; 4Materials Research Institute, The Pennsylvania State University, University Park, PA, USA*These authors contributed equally to this workBackground: Inflammatory cells exhibit an elevated level of protoporphyrin IX (PpIX after the administration of 5-aminolevulinic acid (ALA. Here, we investigate the sonodynamic effects of ALA-derived PpIX (ALA-PpIX on macrophages, which are the pivotal inflammatory cells in atherosclerosis.Methods and results: Cultured THP-1 macrophages were incubated with ALA. Fluorescence microscope and fluorescence spectrometer detection showed that intracellular PpIX increased with the concentration of ALA in the incubation solution in a time dependent manner; the highest level of intracellular PpIX was observed after 3-hour incubation. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assays demonstrated that lower concentrations (less than 2 mM of ALA have no influence on cell viability (more than 90% of cells survived, but sonodynamic therapy (SDT with a low concentration of ALA significantly decreased the survival rate of cells, and the effect was increased with both ALA concentration and ultrasound exposure time. Cell apoptosis and necrosis induced by ALA-mediated SDT (ALA-SDT were measured using

  19. Cysteine amide adduct formation from carboxylic acid drugs via UGT-mediated bioactivation in human liver microsomes.

    Harada, H; Toyoda, Y; Endo, T; Kobayashi, M

    2015-10-01

    Although chemical trapping has been widely used to evaluate cytochrome P450-mediated drug bioactivation, thus far, only a few in vitro-trapping studies have been performed on UDP-glucuronosyltransferase (UGT)-mediated drug bioactivation. In this study, we used cysteine (Cys) as trapping agent to gain new insights into the UGT-mediated bioactivation involving acyl glucuronides of carboxylic acid drugs. Diclofenac, ketoprofen and ibuprofen were incubated in human liver microsomes with UDPGA and Cys, followed by analysis using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). The N-acyl-Cys amide adduct of diclofenac was characterized by mass analysis and was detectable even in photodiode array analysis. Our data indicated that the formation of such adducts reflects the reactivity of the corresponding acyl glucuronides. In addition, it was suggested that the adduct formation requires an N-terminal Cys moiety with both a free amine and a free thiol group, from the results using various cysteine derivatives. We propose that the S-acyl-Cys thioester adduct can form via transacylation of an acyl glucuronide and can then form to an N-acyl-Cys amide adduct through intramolecular S- to N-acyl rearrangement. This series of the reactions has important implications as a possible bioactivation mechanism for covalent binding of carboxylic acid drugs to macromolecules. PMID:26601426

  20. Phosphorus-carbon bond formation by lewis Acid catalyzed/mediated addition of silylphosphines.

    Hayashi, Minoru; Matsuura, Yutaka; Nishimura, Yasunobu; Yamasaki, Toshikazu; Imai, Yoshito; Watanabe, Yutaka

    2007-09-28

    Triethylaluminum-catalyzed/mediated addition of a silylphosphine to aldehydes and epoxides is described. Organophosphines containing a silyloxy group at the alpha- or beta-position on the alkyl substituent are successfully prepared in good yields. PMID:17784776

  1. Insoluble Fe-humic acid complex as a solid-phase electron mediator for microbial reductive dechlorination.

    Zhang, Chunfang; Zhang, Dongdong; Li, Zhiling; Akatsuka, Tetsuji; Yang, Suyin; Suzuki, Daisuke; Katayama, Arata

    2014-06-01

    We report that the insoluble Fe-HA complex, which was synthesized with both commercial Aldrich humic acid (HA) and natural HA, functions as a solid-phase electron mediator (EM) for the anaerobic microbial dechlorination of pentachlorophenol. Spectroscopic characterizations and sequential Fe extraction demonstrated that the Fe-HA complex was predominated with Na4P2O7-labile Fe (represented as the organically bound Fe fraction) and poorly ordered Fe fraction (the fraction left in the residue after the sequential extraction), which were associated with different possible binding processes with carboxylate and phenolic groups. The change in the electron-mediating activity caused by Fe extraction indicated that the electron-mediating function of the Fe-HA complex is attributable to the Na4P2O7-labile Fe fraction. The Fe-HA complex also accelerated the microbial reduction of Fe(III) oxide, which suggested the presence of multiple electron-mediating functions in the complex. The electron shuttle assay showed that the Fe-HA complex had an electron-accepting capacity of 0.82 mequiv g(-1) dry Fe-HA complex. The presence of redox-active moieties in the Fe-HA complex was verified by cyclic voltammetry analysis of the sample after electrical reduction, with a redox potential estimated at 0.02 V (vs a standard hydrogen electrode). PMID:24758743

  2. Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells.

    Jie Hong

    Full Text Available Mechanisms of the progression from Barrett's esophagus (BE to esophageal adenocarcinoma (EA are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA.

  3. Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells

    Cao, Weibiao

    2016-01-01

    Mechanisms of the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK) inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA. PMID:26901778

  4. Treating cutaneous squamous cell carcinoma using 5-aminolevulinic acid polylactic-co-glycolic acid nanoparticle-mediated photodynamic therapy in a mouse model

    Wang X

    2015-01-01

    Full Text Available Xiaojie Wang,1,2,* Lei Shi,2,* Qingfeng Tu,2 Hongwei Wang,3 Haiyan Zhang,2 Peiru Wang,2 Linglin Zhang,2 Zheng Huang,4 Feng Zhao,5 Hansen Luan,5 Xiuli Wang2 1Shanghai Skin Diseases Clinical College of Anhui Medical University, 2Shanghai Skin Disease Hospital, 3Huadong Hospital, Fudan University, Shanghai, 4MOE Key Laboratory of OptoElectronic Science and Technology for Medicine, Fujian Normal University, Fuzhou, 5National Pharmaceutical Engineering Research Center, China State Institute of Pharmaceutical Industry, Shanghai, People’s Republic of China *These authors contributed equally to this study Background: Squamous cell carcinoma (SCC is a common skin cancer, and its treatment is still difficult. The aim of this study was to evaluate the effectiveness of nanoparticle (NP-assisted 5-aminolevulinic acid (ALA delivery for topical photodynamic therapy (PDT of cutaneous SCC.Materials and methods: Ultraviolet-induced cutaneous SCCs were established in hairless mice. ALA-loaded polylactic-co-glycolic acid (PLGA NPs were prepared and characterized. The kinetics of ALA PLGA NP-induced protoporphyrin IX fluorescence in SCCs, therapeutic efficacy of ALA NP-mediated PDT, and immune responses were examined.Results: PLGA NPs enhanced protoporphyrin IX production in SCC. ALA PLGA NP-mediated topical PDT was more effective than free ALA of the same concentration in treating cutaneous SCC.Conclusion: PLGA NPs provide a promising strategy for delivering ALA in topical PDT of cutaneous SCC. Keywords: 5-aminolevulinic acid (ALA, polylactic-co-glycolic acid (PLGA, nanoparticles (NPs, cutaneous squamous cell carcinoma (SCC, photodynamic therapy (PDT, microneedling

  5. Ascorbic acid inhibition of Candida albicans Hsp90-mediated morphogenesis occurs via the transcriptional regulator Upc2.

    Van Hauwenhuyse, Frédérique; Fiori, Alessandro; Van Dijck, Patrick

    2014-10-01

    Morphogenetic transitions of the opportunistic fungal pathogen Candida albicans are influenced by temperature changes, with induction of filamentation upon a shift from 30 to 37°C. Hsp90 was identified as a major repressor of an elongated cell morphology at low temperatures, as treatment with specific inhibitors of Hsp90 results in elongated growth forms at 30°C. Elongated growth resulting from a compromised Hsp90 is considered neither hyphal nor pseudohyphal growth. It has been reported that ascorbic acid (vitamin C) interferes with the yeast-to-hypha transition in C. albicans. In the present study, we show that ascorbic acid also antagonizes the morphogenetic change caused by hampered Hsp90 function. Further analysis revealed that Upc2, a transcriptional regulator of genes involved in ergosterol biosynthesis, and Erg11, the target of azole antifungals, whose expression is in turn regulated by Upc2, are required for this antagonism. Ergosterol levels correlate with elongated growth and are reduced in cells treated with the Hsp90 inhibitor geldanamycin (GdA) and restored by cotreatment with ascorbic acid. In addition, we show that Upc2 appears to be required for ascorbic acid-mediated inhibition of the antifungal activity of fluconazole. These results identify Upc2 as a major regulator of ascorbic acid-induced effects in C. albicans and suggest an association between ergosterol content and elongated growth upon Hsp90 compromise. PMID:25084864

  6. TRIM32 promotes retinoic acid receptor {alpha}-mediated differentiation in human promyelogenous leukemic cell line HL60

    Sato, Tomonobu [Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638 (Japan); Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo 060-8638 (Japan); Okumura, Fumihiko [Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638 (Japan); Iguchi, Akihiro; Ariga, Tadashi [Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo 060-8638 (Japan); Hatakeyama, Shigetsugu, E-mail: hatas@med.hokudai.ac.jp [Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638 (Japan)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer TRIM32 enhanced RAR{alpha}-mediated transcriptional activity even in the absence of RA. Black-Right-Pointing-Pointer TRIM32 stabilized RAR{alpha} in the human promyelogenous leukemic cell line HL60. Black-Right-Pointing-Pointer Overexpression of TRIM32 in HL60 cells induced granulocytic differentiation. Black-Right-Pointing-Pointer TRIM32 may function as a coactivator for RAR{alpha}-mediated transcription in APL cells. -- Abstract: Ubiquitination, one of the posttranslational modifications, appears to be involved in the transcriptional activity of nuclear receptors including retinoic acid receptor {alpha} (RAR{alpha}). We previously reported that an E3 ubiquitin ligase, TRIM32, interacts with several important proteins including RAR{alpha} and enhances transcriptional activity of RAR{alpha} in mouse neuroblastoma cells and embryonal carcinoma cells. Retinoic acid (RA), which acts as a ligand to nuclear receptors including RAR{alpha}, plays crucial roles in development, differentiation, cell cycles and apoptosis. In this study, we found that TRIM32 enhances RAR{alpha}-mediated transcriptional activity even in the absence of RA and stabilizes RAR{alpha} in the human promyelogenous leukemic cell line HL60. Moreover, we found that overexpression of TRIM32 in HL60 cells suppresses cellular proliferation and induces granulocytic differentiation even in the absence of RA. These findings suggest that TRIM32 functions as one of the coactivators for RAR{alpha}-mediated transcription in acute promyelogenous leukemia (APL) cells, and thus TRIM32 may become a potentially therapeutic target for APL.

  7. Acid Stress-Mediated Metabolic Shift in Lactobacillus sanfranciscensis LSCE1 ▿

    Serrazanetti, Diana I.; Ndagijimana, Maurice; Sado-Kamdem, Sylvain L.; Corsetti, Aldo; Vogel, Rudi F.; Ehrmann, Matthias; Guerzoni, M. Elisabetta

    2011-01-01

    Lactobacillus sanfranciscensis LSCE1 was selected as a target organism originating from recurrently refreshed sourdough to study the metabolic rerouting associated with the acid stress exposure during sourdough fermentation. In particular, the acid stress induced a metabolic shift toward overproduction of 3-methylbutanoic and 2-methylbutanoic acids accompanied by reduced sugar consumption and primary carbohydrate metabolite production. The fate of labeled leucine, the role of different nutrie...

  8. Epoxy fatty acids and inhibition of the soluble epoxide hydrolase selectively modulate GABA mediated neurotransmission to delay onset of seizures.

    Bora Inceoglu

    Full Text Available In the brain, seizures lead to release of large amounts of polyunsaturated fatty acids including arachidonic acid (ARA. ARA is a substrate for three major enzymatic routes of metabolism by cyclooxygenase, lipoxygenase and cytochrome P450 enzymes. These enzymes convert ARA to potent lipid mediators including prostanoids, leukotrienes and epoxyeicosatrienoic acids (EETs. The prostanoids and leukotrienes are largely pro-inflammatory molecules that sensitize neurons whereas EETs are anti-inflammatory and reduce the excitability of neurons. Recent evidence suggests a GABA-related mode of action potentially mediated by neurosteroids. Here we tested this hypothesis using models of chemically induced seizures. The level of EETs in the brain was modulated by inhibiting the soluble epoxide hydrolase (sEH, the major enzyme that metabolizes EETs to inactive molecules, by genetic deletion of sEH and by direct administration of EETs into the brain. All three approaches delayed onset of seizures instigated by GABA antagonists but not seizures through other mechanisms. Inhibition of neurosteroid synthesis by finasteride partially blocked the anticonvulsant effects of sEH inhibitors while the efficacy of an inactive dose of neurosteroid allopregnanolone was enhanced by sEH inhibition. Consistent with earlier findings, levels of prostanoids in the brain were elevated. In contrast, levels of bioactive EpFAs were decreased following seizures. Overall these results demonstrate that EETs are natural molecules which suppress the tonic component of seizure related excitability through modulating the GABA activity and that exploration of the EET mediated signaling in the brain could yield alternative approaches to treat convulsive disorders.

  9. Acidic environment augments FcεRI-mediated production of IL-6 and IL-13 in mast cells

    Although blood pH is maintained in a narrow range of around pH 7.4 in living organisms, inflammatory loci are characterized by acidic conditions. Mast cells tend to reside close to the surface of the body in areas such as the mucosa and skin where they may be exposed to exogenous acids, and they play an important role in immune responses. However, little is known about the effects of extracellular acidification on the functions of mast cell. Here, we found that extracellular acidification increased the dinitrophenyl-conjugated human serum albumin (DNP-HSA)-induced production of interleukin (IL)-6 and IL-13 in MC/9 cells or bone marrow-derived mouse mast cells sensitized with anti-DNP IgE. Extracellular acidification also inhibited migration of MC/9 cells toward DNP-HSA. In addition, acidic pH stimulated antigen-induced activation of p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt). These findings suggest that extracellular acidification augmented antigen/IgE-induced and FcεRI-mediated production of IL-6 and IL-13 in mast cells, and that this was associated with the enhancement of p38 MAPK and Akt activation. - Highlights: • Antigen-induced IL-6 and IL-13 production was augmented by acidic pH in mast cells. • Acidic pH-induced actions were associated with activation of p38 MAPK and Akt. • Inhibition of p38 MAPK and Akt attenuated cytokine responses to acidic pH. • Acidic pH effects are not attributable to actions of known proton-sensing GPCRs

  10. Acidic environment augments FcεRI-mediated production of IL-6 and IL-13 in mast cells

    Kamide, Yosuke, E-mail: m08702012@gunma-u.ac.jp [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Clinical Research Center for Allergy and Rheumatology, Sagamihara National Hospital, Sagamihara (Japan); Ishizuka, Tamotsu [Third Department of Internal Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Tobo, Masayuki [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Tsurumaki, Hiroaki [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Aoki, Haruka; Mogi, Chihiro [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Nakakura, Takashi [Department of Anatomy, Graduate School of Medicine, Teikyo University, Tokyo (Japan); Yatomi, Masakiyo; Ono, Akihiro; Koga, Yasuhiko [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Sato, Koichi [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan); Hisada, Takeshi [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Dobashi, Kunio [Gunma University Graduate School of Health Sciences, Maebashi (Japan); Yamada, Masanobu [Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi (Japan); Okajima, Fumikazu [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi (Japan)

    2015-08-28

    Although blood pH is maintained in a narrow range of around pH 7.4 in living organisms, inflammatory loci are characterized by acidic conditions. Mast cells tend to reside close to the surface of the body in areas such as the mucosa and skin where they may be exposed to exogenous acids, and they play an important role in immune responses. However, little is known about the effects of extracellular acidification on the functions of mast cell. Here, we found that extracellular acidification increased the dinitrophenyl-conjugated human serum albumin (DNP-HSA)-induced production of interleukin (IL)-6 and IL-13 in MC/9 cells or bone marrow-derived mouse mast cells sensitized with anti-DNP IgE. Extracellular acidification also inhibited migration of MC/9 cells toward DNP-HSA. In addition, acidic pH stimulated antigen-induced activation of p38 mitogen-activated protein kinase (MAPK) and protein kinase B (Akt). These findings suggest that extracellular acidification augmented antigen/IgE-induced and FcεRI-mediated production of IL-6 and IL-13 in mast cells, and that this was associated with the enhancement of p38 MAPK and Akt activation. - Highlights: • Antigen-induced IL-6 and IL-13 production was augmented by acidic pH in mast cells. • Acidic pH-induced actions were associated with activation of p38 MAPK and Akt. • Inhibition of p38 MAPK and Akt attenuated cytokine responses to acidic pH. • Acidic pH effects are not attributable to actions of known proton-sensing GPCRs.

  11. Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

    Aili, David; Javakhishvili, Irakli; Han, Junyoung;

    2016-01-01

    the phosphoric acid uptake and to obtain mechanically robust membranes, the amino-functional polybenzimidazole derivative is blended with high molecular weight poly [2,2′-(m-phenylene)-5,5′-bisbenzimidazole] at different ratios. Due to the high acid uptake, the homogenous blend membranes show enhanced proton...

  12. Dietary supplementation with arachidonic acid in tilapia (Oreochromis mossambicus) reveals physiological effects not mediated by prostaglandins.

    Anholt, R.D. van; Spanings, F.A.T.; Koven, W.M.; Wendelaar Bonga, S.E.

    2004-01-01

    This study aims to clarify the role of the polyunsaturated fatty acid arachidonic acid (ArA, 20:4n-6) in the stress response of Mozambique tilapia (Oreochromis mossambicus). ArA is converted into eicosanoids, including prostaglandins, which can influence the response to stressors. Tilapia, a species

  13. Point-of-care multiplexed assays of nucleic acids using microcapillary-based loop-mediated isothermal amplification.

    Zhang, Yi; Zhang, Lu; Sun, Jiashu; Liu, Yulei; Ma, Xingjie; Cui, Shangjin; Ma, Liying; Xi, Jianzhong Jeff; Jiang, Xingyu

    2014-07-15

    This report demonstrates a straightforward, robust, multiplexed and point-of-care microcapillary-based loop-mediated isothermal amplification (cLAMP) for assaying nucleic acids. This assay integrates capillaries (glass or plastic) to introduce and house sample/reagents, segments of water droplets to prevent contamination, pocket warmers to provide heat, and a hand-held flashlight for a visual readout of the fluorescent signal. The cLAMP system allows the simultaneous detection of two RNA targets of human immunodeficiency virus (HIV) from multiple plasma samples, and achieves a high sensitivity of two copies of standard plasmid. As few nucleic acid detection methods can be wholly independent of external power supply and equipment, our cLAMP holds great promise for point-of-care applications in resource-poor settings. PMID:24937125

  14. Vigabatrin absorption is mediated via the proton-coupled amino acid transporter PAT1 – in vitro and in vivo

    Nøhr, Martha Kampp; Juul, Rasmus Vestergaard; Hansen, Steen Honore'; Brodin, Birger; Holm, René; Kreilgaard, Mads; Nielsen, Carsten Uhd

    2013-01-01

    proton coupled amino acid transporter PAT1, however the actual transport mechanisms involved in transepithelial absorption have not been clarified. The aim of the study was to investigate whether the transepithelial absorption of vigabatrin is mediated by PAT1 – in vitro as well as in vivo. Methods The.......4. The transepithelial transport across Caco-2 cell monolayers was polarized in the lumen-to-blood direction in the presence of a proton gradient. The presence of PAT1-ligands significantly decreased the permeability of vigabatrin across Caco-2 cell monolayers. In Sprague Dawley rats the presence of PAT1......-ligands altered the pharmacokinetic profile of vigabatrin with an apparent prolonged absorption of vigabatrin. Conclusions Transport of vigabatrin across Caco-2 cell monolayers was polarized in the lumen-to-blood directions, dependent on an acidic pH in the lumen compartment and inhibited by PAT1-ligands...

  15. Ceramide formation mediated by acid sphingomyelinase facilitates endosomal escape of caliciviruses.

    Shivanna, Vinay; Kim, Yunjeong; Chang, Kyeong-Ok

    2015-09-01

    Our recent results demonstrated that bile acids facilitate virus escape from the endosomes into the cytoplasm for successful replication of porcine enteric calicivirus (PEC). We report a novel finding that bile acids can be substituted by cold treatment for endosomal escape and virus replication. This endosomal escape by cold treatment or bile acids is associated with ceramide formation by acid sphingomyelinase (ASM). ASM catalyzes hydrolysis of sphingomyelin into ceramide, which is known to destabilize lipid bilayer. Treatment of LLC-PK cells with bile acids or cold led to ceramide formation, and small molecule antagonists or siRNA of ASM blocked ceramide formation in the endosomes and significantly reduced PEC replication. Inhibition of ASM resulted in the retention of PEC, feline calicivirus or murine norovirus in the endosomes in correlation with reduced viral replication. These results suggest the importance of viral escape from the endosomes for the replication of various caliciviruses. PMID:25985440

  16. SuperSAGE analysis of the Nicotiana attenuata transcriptome after fatty acid-amino acid elicitation (FAC: identification of early mediators of insect responses

    Baldwin Ian T

    2010-04-01

    Full Text Available Abstract Background Plants trigger and tailor defense responses after perception of the oral secretions (OS of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown. Results We used SuperSAGE combined with 454 sequencing to quantify the early transcriptional changes elicited by the FAC N-linolenoyl-glutamic acid (18:3-Glu and virus induced gene silencing (VIGS to examine the function of candidate genes in the M. sexta-N. attenuata interaction. The analysis targeted mRNAs encoding regulatory components: rare transcripts with very rapid FAC-elicited kinetics (increases within 60 and declines within 120 min. From 12,744 unique Tag sequences identified (UniTags, 430 and 117 were significantly up- and down-regulated ≥ 2.5-fold, respectively, after 18:3-Glu elicitation compared to wounding. Based on gene ontology classification, more than 25% of the annotated UniTags corresponded to putative regulatory components, including 30 transcriptional regulators and 22 protein kinases. Quantitative PCR analysis was used to analyze the FAC-dependent regulation of a subset of 27 of these UniTags and for most of them a rapid and transient induction was confirmed. Six FAC-regulated genes were functionally characterized by VIGS and two, a putative lipid phosphate phosphatase (LPP and a protein of unknown function, were identified as important mediators of the M. sexta-N. attenuata interaction. Conclusions The analysis of the early changes in the transcriptome of N. attenuata after FAC elicitation using SuperSAGE/454 has identified regulatory genes involved in insect-specific mediated responses in plants. Moreover, it has provided a foundation for the identification of additional novel regulators

  17. Solanum lycopersicum IAA15 functions in the 2,4-dichlorophenoxyacetic acid herbicide mechanism of action by mediating abscisic acid signalling.

    Xu, Tao; Wang, Yanling; Liu, Xin; Gao, Song; Qi, Mingfang; Li, Tianlai

    2015-07-01

    2,4-Dichlorophenoxyacetic acid (2,4-D), an important plant growth regulator, is the herbicide most commonly used worldwide to control weeds. However, broad-leaf fruits and vegetables are extremely sensitive to herbicides, which can cause damage and result in lost crops when applied in a manner inconsistent with the directions. Despite detailed knowledge of the mechanism of 2,4-D, the regulation of auxin signalling is still unclear. For example, although the major mediators of auxin signalling, including auxin/indole acetic acid (AUX/IAA) proteins and auxin response factors (ARFs), are known to mediate auxinic herbicides, the underlying mechanisms are still unclear. In this study, the effects of 2,4-D on AUX/IAA gene expression in tomato were investigated, and the two most notably up-regulated genes, SlIAA15 and SlIAA29, were selected for further study. Western blotting revealed the substantial accumulation of both SlIAA15 and SlIAA29, and the expression levels of the corresponding genes were increased following abscisic acid (ABA) and ethylene treatment. Overexpressing SlIAA15, but not SlIAA29, induced a 2,4-D herbicide damage phenotype. The 35S::SlIAA15 line exhibited a strong reduction in leaf stomatal density and altered expression of some R2R3 MYB genes that are putatively involved in the regulation of stomatal differentiation. Further study revealed that root elongation in 35S::SlIAA15 was sensitive to ABA treatment, and was most probably due to the altered expression of an ABA signal transduction gene. In addition, the altered auxin sensitivities of SlIAA15 transformants were also explored. These results suggested that SlIAA15 plays an important role in determining the effects of the herbicide 2,4-D. PMID:25948703

  18. Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

    Klingelhoeffer Christoph; Kämmerer Ulrike; Koospal Monika; Mühling Bettina; Schneider Manuela; Kapp Michaela; Kübler Alexander; Germer Christoph-Thomas; Otto Christoph

    2012-01-01

    Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS) involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100 mmol/L). The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. ...

  19. Visual detection of Ebola virus using reverse transcription loop-mediated isothermal amplification combined with nucleic acid strip detection.

    Xu, Changping; Wang, Hualei; Jin, Hongli; Feng, Na; Zheng, Xuexing; Cao, Zengguo; Li, Ling; Wang, Jianzhong; Yan, Feihu; Wang, Lina; Chi, Hang; Gai, Weiwei; Wang, Chong; Zhao, Yongkun; Feng, Yan; Wang, Tiecheng; Gao, Yuwei; Lu, Yiyu; Yang, Songtao; Xia, Xianzhu

    2016-05-01

    Ebola virus (species Zaire ebolavirus) (EBOV) is highly virulent in humans. The largest recorded outbreak of Ebola hemorrhagic fever in West Africa to date was caused by EBOV. Therefore, it is necessary to develop a detection method for this virus that can be easily distributed and implemented. In the current study, we developed a visual assay that can detect EBOV-associated nucleic acids. This assay combines reverse transcription loop-mediated isothermal amplification and nucleic acid strip detection (RT-LAMP-NAD). Nucleic acid amplification can be achieved in a one-step process at a constant temperature (58 °C, 35 min), and the amplified products can be visualized within 2-5 min using a nucleic acid strip detection device. The assay is capable of detecting 30 copies of artificial EBOV glycoprotein (GP) RNA and RNA encoding EBOV GP from 10(2) TCID50 recombinant viral particles per ml with high specificity. Overall, the RT-LAMP-NAD method is simple and has high sensitivity and specificity; therefore, it is especially suitable for the rapid detection of EBOV in African regions. PMID:26831931

  20. Palmitic acid (16:0) competes with omega-6 linoleic and omega-3 ɑ-linolenic acids for FADS2 mediated Δ6-desaturation.

    Park, Hui Gyu; Kothapalli, Kumar S D; Park, Woo Jung; DeAllie, Christian; Liu, Lei; Liang, Allison; Lawrence, Peter; Brenna, J Thomas

    2016-02-01

    Sapienic acid, 16:1n-10 is the most abundant unsaturated fatty acid on human skin where its synthesis is mediated by FADS2 in the sebaceous glands. The FADS2 product introduces a double bond at the Δ6, Δ4 and Δ8 positions by acting on at least ten substrates, including 16:0, 18:2n-6, and 18:3n-3. Our aim was to characterize the competition for accessing FADS2 mediated Δ6 desaturation between 16:0 and the most abundant polyunsaturated fatty acids (PUFA) in the human diet, 18:2n-6 and 18:3n-3, to evaluate whether competition may be relevant in other tissues and thus linked to metabolic abnormalities associated with FADS2 or fatty acid levels. MCF7 cells stably transformed with FADS2 biosynthesize 16:1n-10 from exogenous 16:0 in preference to 16:1n-7, the immediate product of SCD highly expressed in cancer cell lines, and 16:1n-9 via partial β-oxidation of 18:1n-9. Increasing availability of 18:2n-6 or 18:3n-3 resulted in decreased bioconversion of 16:0 to 16:1n-10, simultaneously increasing the levels of highly unsaturated products. FADS2 cells accumulate the desaturation-elongation products 20:3n-6 and 20:4n-3 in preference to the immediate desaturation products 18:3n-6 and 18:4n-3 implying prompt/coupled elongation of the nascent desaturation products. MCF7 cells incorporate newly synthesized 16:1n-10 into phospholipids. These data suggest that excess 16:0 due to, for instance, de novo lipogenesis from high carbohydrate or alcohol consumption, inhibits synthesis of highly unsaturated fatty acids, and may in part explain why supplemental preformed EPA and DHA in some studies improves insulin resistance and other factors related to diabetes and metabolic syndrome aggravated by excess calorie consumption. PMID:26597785

  1. Novel redox-sensing modules : Accessory protein- and nucleic acid-mediated signaling

    Siedenburg, Gabriele; Groves, Matthew R; Ortiz de Orué Lucana, Darío

    2012-01-01

    SIGNIFICANCE: Organisms have evolved both enzymatic and nonenzymatic pathways to prevent oxidative damage to essential macromolecules, including proteins and nucleic acids. Pathways modulated by different protein-based sensory and regulatory modules ensure a rapid and appropriate response. RECENT AD

  2. Bile Acid-Induced Arrhythmia Is Mediated by Muscarinic M2 Receptors in Neonatal Rat Cardiomyocytes

    Sheikh Abdul Kadir, Siti H; Michele Miragoli; Shadi Abu-Hayyeh; Moshkov, Alexey V.; Qilian Xie; Verena Keitel; Viacheslav O. Nikolaev; Catherine Williamson; Julia Gorelik

    2010-01-01

    BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) is a common disease affecting up to 5% of pregnancies and which can cause fetal arrhythmia and sudden intrauterine death. We previously demonstrated that bile acid taurocholate (TC), which is raised in the bloodstream of ICP, can acutely alter the rate and rhythm of contraction and induce abnormal calcium destabilization in cultured neonatal rat cardiomyocytes (NRCM). Apart from their hepatic functions bile acids are ubiquitous signallin...

  3. The mechanism of downregulation of apolipoprotein M mediated by palmitic acid

    施媛萍

    2014-01-01

    Objective To examine whether palmitic acid downregulates ApoM expression and further to investigate its mechanism.Methods Human hepatoma cell line,HepG2 cells were treated with the media containing palmitic acid(1 mmol/L)and/or PI-3K inhibitor LY294002(10μmol/L),protein kinase C inhibitor GF109203X(GFX,2μmol/L)and/or PARβ/δantagonist GSK3787

  4. A novel FADS1 isoform potentiates FADS2-mediated production of eicosanoid precursor fatty acids

    Park, Woo Jung; Kothapalli, Kumar S. D.; Reardon, Holly T; Lawrence, Peter; Qian, Shu-Bing; Brenna, J. Thomas

    2012-01-01

    The fatty acid desaturase (FADS) genes code for the rate-limiting enzymes required for the biosynthesis of long-chain polyunsaturated fatty acids (LCPUFA). Here we report discovery and function of a novel FADS1 splice variant. FADS1 alternative transcript 1 (FADS1AT1) enhances desaturation of FADS2, leading to increased production of eicosanoid precursors, the first case of an isoform modulating the enzymatic activity encoded by another gene. Multiple protein isoforms were detected in primate...

  5. Hyperglycemia-induced teratogenesis is mediated by a functional deficiency of arachidonic acid.

    Goldman, A S; Baker, L; Piddington, R; Marx, B; Herold, R; Egler, J

    1985-01-01

    Congenital malformations now represent the largest single cause of mortality in the infant of the diabetic mother. The mechanism by which diabetes exerts its teratogenic effects is not known. This study evaluated whether arachidonic acid might be involved, a possibility raised by the role of arachidonic acid in palatal elevation and fusion, processes analogous to neural tube folding and fusion. This hypothesis was tested in two animal models of diabetic embryopathy, the in vivo pregnant diabe...

  6. Glycinergic-Fipronil Uptake Is Mediated by an Amino Acid Carrier System and Induces the Expression of Amino Acid Transporter Genes in Ricinus communis Seedlings.

    Xie, Yun; Zhao, Jun-Long; Wang, Chuan-Wei; Yu, Ai-Xin; Liu, Niu; Chen, Li; Lin, Fei; Xu, Han-Hong

    2016-05-18

    Phloem-mobile insecticides are efficient for piercing and sucking insect control. Introduction of sugar or amino acid groups to the parent compound can improve the phloem mobility of insecticides, so a glycinergic-fipronil conjugate (GlyF), 2-(3-(3-cyano-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-((trifluoromethyl)sulfinyl)-1H-pyrazole-5-yl)ureido) acetic acid, was designed and synthesized. Although the "Kleier model" predicted that this conjugate is not phloem mobile, GlyF can be continually detected during a 5 h collection of Ricinus communis phloem sap. Furthermore, an R. communis seedling cotyledon disk uptake experiment demonstrates that the uptake of GlyF is sensitive to pH, carbonyl cyanide m-chlorophenylhydrazone (CCCP), temperature, and p-chloromercuribenzenesulfonic acid (pCMBS) and is likely mediated by amino acid carrier system. To explore the roles of amino acid transporters (AATs) in GlyF uptake, a total of 62 AAT genes were identified from the R. communis genome in silico. Phylogenetic analysis revealed that AATs in R. communis were organized into the ATF (amino acid transporter) and APC (amino acid, polyaminem and choline transporter) superfamilies, with five subfamilies in ATF and two in APC. Furthermore, the expression profiles of 20 abundantly expressed AATs (cycle threshold (Ct) values AAT genes, RcLHT6, RcANT15, RcProT2, and RcCAT2, were induced by the GlyF treatment in R. communis seedlings. On the basis of the observation that the expression profile of the four candidate genes is similar to the time course observation for GlyF foliar disk uptake, it is suggested that those four genes are possible candidates involved in the uptake of GlyF. These results contribute to a better understanding of the mechanism of GlyF uptake as well as phloem loading from a molecular biology perspective and facilitate functional characterization of candidate AAT genes in future studies. PMID:27092815

  7. Novel Endogenous Proresolving Molecules:Essential Fatty Acid-Derived and Gaseous Mediators in the Resolution of Inflammation.

    Shinohara, Masakazu; Serhan, Charles N

    2016-06-01

    Acute inflammation is a fundamental, protective response that orchestrates immune system to address harmful stimuli both from within and via invasion. New evidences indicate that the resolution of acute inflammation is not simply passive but active and highly regulated processes coordinated by new families of potent bioactive lipid mediators (LMs), coined specialized proresolving mediators (SPMs). These SPMs are biosynthesized from n-3 polyunsaturated fatty acids. Low concentrations of SPM (nM range) stimulate proresolving cellular processes, such as inhibition of neutrophil infiltration, enhancement of macrophage phagocytosis of bacteria and efferocytosis of cellular debris, and reduction of inflammatory pain through specific G-protein coupled receptors.Of the many bioactive mediators that regulate inflammation resolution, low-dose carbon monoxide (CO) functions as a tissue-protective gaso-transmitter that is endogenously produced by the heme oxygenase (HO) system. Specific SPMs activate the HO system, which in turn enhances endogenous CO production locally, thus establishing a protective feed-forward circuit between SPMs and CO. In addition, treatment with low-dose CO and SPMs exerts protective effects against ischemia/reperfusion injury by decreasing leukocyte-platelet interaction and proinflammatory LM levels.Recent studies reviewed herein assessed the impact of SPMs and low-dose inhaled CO on inflammatory diseases. LM metabololipidomics approach allows the assessment of the efficacy of novel treatments with SPMs and low-dose CO. Moreover, this approach indicates the regions where the action of individual LMs may be physiologically relevant and when these LMs are produced in vivo to serve their proresolving mediator functions that may also permit new directions for treating human diseases. PMID:27052783

  8. Valproic acid overcomes transforming growth factor-β-mediated sorafenib resistance in hepatocellular carcinoma

    Matsuda, Yasunobu; Wakai, Toshifumi; Kubota, Masayuki; Osawa, Mami; Hirose, Yuki; Sakata, Jun; Kobayashi, Takashi; Fujimaki, Shun; Takamura, Masaaki; Yamagiwa, Satoshi; Aoyagi, Yutaka

    2014-01-01

    Sorafenib is a multi-kinase inhibitor approved for hepatocellular carcinoma, but rarely causes tumor regression in patients with chronic liver diseases. To investigate whether growth factor-mediated signaling is involved in sorafenib resistance, HepG2 and PLC/PRF/5 hepatoma cells were exposed to epidermal growth factor (EGF), hepatocyte growth factor (HGF) or transforming growth factor-β (TGF-β) prior to treatment with sorafenib. Furthermore, to identify an effective combination treatment wit...

  9. Hypochlorous acid-mediated oxidation of lipid components and antioxidants present in low-density lipoproteins

    Pattison, David I; Hawkins, Clare L; Davies, Michael Jonathan

    2003-01-01

    antioxidants are relatively ineffective as direct scavengers for HOCl as compared to water soluble antioxidants (e.g., ascorbate, k ca. 10(6) M(-)(1) s(-)(1)). The reaction of HOCl with hydroquinone (a simple model for ubiquinol-10) was also investigated both in aqueous solution (k = 45 M(-)(1) s(-)(1)) and in...... models compare well with experimental data and can be used to predict the effects of HOCl-mediated oxidation on LDL composition....

  10. Citric acid mediated phyto extraction of cadmium by maize (zea mays l.)

    The aim of the investigation was to determine the potential of citric acid for accumulation and translocation of cadmium and their effect on maize growth. The plants were grown in small plastic glasses and treated with 300 mg kg/sup -1/ CdCl/sub 2/ and 0, 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid. After 10 days, the plants were harvested, dried and root and shoot biomass weighed. To study the efficiency of maize to bioaccumulate metal, uptake of cadmium was studied in the root and shoot. The results showed that heavy metal accumulated more in roots than the shoots and application of citric acid depressed Cd uptake at all concentrations. Percent decrease in Cd uptake was 58, 35, 26, 25 and 63, 46, 44, 42 by Sahiwal-2002 and Pak-affgoee, respectively at 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid application. Maize proved to be an effective accumulator for cadmium, however, neither concentration of citric acid showed advantages for phytoextraction of cadmium. (author)

  11. Electrochemical oxidation of ascorbic acid mediated by carbon nano tubes/ Li+/ carbon paste modified solid electrode

    Multi-walled carbon nano tube (MWCNT) was used to modify BPPG electrode because of its unique structure and extraordinary properties. MWCNT modified electrode exhibited obvious enhancing and electro catalyzing effects to the oxidation of ascorbic acid using cyclic voltammetry technique. MWCNT was bonded on BPPG electrode surface using carbon paste with ratio of 30 % (w/ W) carbon paste (binder): 70 % (w/ w) MWCNT. This method of modification has lowered the capacitance background current and enabled lower detection limit of ascorbic acid concentration. The electrical conductivity property of MWCNT modified electrode was further improved with the intercalation with lithium ion and resulted in current enhancement of 2 times on the oxidation current of ascorbic acid. Parameters of pH and temperature showed significant relation to the sensitivity of MWCNT modified electrode. Under the optimized parameters, the calibration curve constructed was linear up from 50 μM to 5 mM with sensitivity of 34.5 mA M-1. The practical application of MWCNT modified electrode was demonstrated with Vitamin C pill and orange juice. Good reproducibility and recovery of ascorbic acid concentration showed the feasibility of MWCNT modified electrode to be used in the detection of ascorbic acid in aqueous solution. This also proposed MWCNT modified BPPG electrode possessed advantages such as low detection limit, high stability, low cost and simplicity in fabrication. (author)

  12. Lithocholic acid induction of the FGF19 promoter in intestinal cells is mediated by PXR

    Wolfgang Wistuba; Carsten Gnewuch; Gerhard Liebisch; Gerd Schmitz; Thomas Langmann

    2007-01-01

    AIM: To study the effect of the toxic secondary bile acid lithocholic acid (LCA) on the expression of fibroblast growth factor 19 (FGF19) in intestinal cells and to characterize the pregnane-X-receptor (PXR) response of the FGF19 promoter region.METHODS: The intestinal cell line LS174T was stimulated with various concentrations of chenodeoxycholic acid and lithocholic acid for several time points.FGF19 mRNA levels were determined with quantitative realtime RT-PCR. FGF19 deletion promoter constructs were generated and the LCA response was analzyed in reporter assays. Co-transfections with PXR and RXR were carried out to study FGF19 regulation by these factors.RESULTS: LCA and CDCA strongly up-regulate FGF19 mRNA expression in LS174T cells in a time and dose dependent manner. Using reporter gene assays with several deletion constructs we found that the LCA responsive element in the human FGF19 promoter maps to the proximal regulatory region containing two potential binding sites for PXR. Overexpression of PXR and its dimerization partner retinoid X receptor (RXR) and stimulation with LCA or the potent PXR ligand rifampicin leads to a significant induction of FGF19 promoter activity in intestinal cells.CONCLUSION: LCA induced feedback inhibition of bile acid synthesis in the liver is likely to be regulated by PXR inducing intestinal FGF19 expression.

  13. Investigation of surfactant mediated acid-base charging of mineral oxide particles dispersed in apolar systems.

    Gacek, Matthew M; Berg, John C

    2012-12-21

    The current work examines the role of acid-base properties on particle charging in apolar media. Manipulating the polarity and magnitude of charge in such systems is of growing interest to a number of applications. A major hurdle to the implementation of this technology is that the mechanism(s) of particle charging remain a subject of debate. The authors previously conducted a study of the charging of a series of mineral oxide particles dispersed in apolar systems that contained the surfactant AOT. It was observed that there was a correlation between the particle electrophoretic mobility and the acid-base nature of the particle, as characterized by aqueous point of zero charge (PZC) or the isoelectric point (IEP). The current study investigates whether or not a similar correlation is observed with other surfactants, namely, the acidic Span 80 and the basic OLOA 11000. This is accomplished by measuring the electrophoretic mobility of a series of mineral oxides that are dispersed in Isopar-L containing various concentrations of either Span 80 or OLOA 11000. The mineral oxides used have PZC values that cover a wide range of pH, providing a systematic study of how particle and surfactant acid-base properties impact particle charge. It was found that the magnitude and polarity of particle surface charge varied linearly with the particle PZC for both surfactants used. In addition, the point at which the polarity of charge reversed for the basic surfactant OLOA 11000 was shifted to a pH of approximately 8.5, compared to the previous result of about 5 for AOT. This proves that both surfactant and particle acid-base properties are important, and provides support for the theory of acid-base charging in apolar media. PMID:23157688

  14. Lewis-Acid-Mediated Stereospecific Radical Polymerization of Acrylimides Bearing Chiral Oxazolidinones.

    Fujita, Takehiro; Yamago, Shigeru

    2015-12-14

    Lewis acid (MgBr2)-catalyzed radical polymerization of acrylimides bearing chiral oxazolidinones gave highly isotactic polyacrylimides with up to >99% meso tetrad (mmm) selectivity. Polymerization in the absence of Lewis acid gave atactic polymers with 80% racemo diad (r) selectivity; the selectivity was deliberately tuned from 80% r to >99% mmm by varying the polymerization conditions. The polyacrylimide was quantitatively converted to corresponding polyacrylates while preserving the stereoregularity, thus providing a general method for the synthesis of atactic to isotactic polyacrylates. PMID:26500040

  15. The Modification of Cellulosic Surface with Fatty Acids via Plasma Mediated Reactions

    Nada, Ahmed Ali Ahmed

    Much attention has been paid recently to understand the healing process made by the human body, in order to develop new approaches for promoting healing. The wound healing process includes four main phases, namely, hemostatic, inflammatory, proliferation, and remodeling, which take place successively. The human body can provide all the requirements of the healing process in normal wounds, unless there is a kind of deficiency of the skin function or massive fluid losses of vast wounds. Therefore, wound care of non-healing wounds has recently been the growing concern of many applications. The goal of this work is to explore the development of a new cellulose-based wound dressing composite that contain or release wound healing agents attained via dry textile chemical finishing techniques (thermal curing-plasma treatment). The synthesis of different wound healing agents derived from fatty acids and attached chemically to cellulose or even delivered through cyclodextrine modified cellulose are reported in this work. First, free fatty acids, which are obtained from commercial vegetable oils, were identified as wound healing agents. Many of these free acids are known to bind with and deactivate the proteases associated with inflammation at a wound site. Linoleic acid is extracted from commercial products of safflower seed oil while ricinoleic acid is obtained from castor oil. Conjugated linoleic acid was synthesized. Un-conjugated linoleic acid was used to prepare two derivatives namely linoleic azide and allylic ketone of linoleic acid. Different cellulose derivatives such as cellulose peroxide, iododeoxycellulose and cellulose diazonium salt in different degree of substitutions were synthesized in order to facilitate the free radical reaction with the fatty acid derivatives. New modified cellulosic products were synthesized by reacting the cellulosic and the linoleic acid derivatives via thermal or plasma technique and characterized by FT-IR ATR, the wettability test

  16. Gene expression profiling identifies mechanisms of protection to recurrent trinitrobenzene sulfonic acid colitis mediated by probiotics

    Mariman, R.; Kremer, S.H.A.; Erk, M. van; Lagerweij, T.; Koning, F.; Nagelkerken, L.

    2012-01-01

    Background: Host-microbiota interactions in the intestinal mucosa play a major role in intestinal immune homeostasis and control the threshold of local inflammation. The aim of this study was to evaluate the efficacy of probiotics in the recurrent trinitrobenzene sulfonic acid (TNBS)-induced colitis

  17. Replication of the five novel loci for uric acid concentrations and potential mediating mechanisms

    van der Harst, Pim; Bakker, Stephan J. L.; de Boer, Rudolf A.; Wolffenbuttel, Bruce H. R.; Johnson, Toby; Caulfield, Mark J.; Navis, Gerjan

    2010-01-01

    Uric acid (UA) is the final catabolic product of purine metabolism and elevated levels are associated with diabetes and cardiovascular disease. A recent meta-analysis of genome-wide association studies totalling 28 141 participants identified five novel loci associated with serum UA levels. In our p

  18. Photon and Water Mediated Sulfur Oxide and Acid Chemistry in the Atmosphere of Venus

    Kroll, Jay A.; Vaida, Veronica

    2014-06-01

    Sulfur compounds have been observed in the atmospheres of a number of planetary bodies in our solar system including Venus, Earth, Mars, Io, Europa, and Callisto. The global cloud cover on Venus located at an altitude between 50 and 80 kilometers is composed primarily of sulfuric acid (H_2SO_4) and water. Planetary photochemical models have attempted to explain observations of sulfuric acid and sulfur oxides with significant discrepancies remaining between models and observation. In particular, high SO_2 mixing ratios are observed above 90 km which exceed model predictions by orders of magnitude. Work recently done in the Vaida lab has shown red light can drive photochemistry through overtone pumping for acids like H_2SO_4 and has been successful in explaining much of the sulfur chemistry in Earth's atmosphere. Water can have a number of interesting effects such as catalysis, suppression, and anti-catalysis of thermal and photochemical processes. We investigate the role of water complexes in the hydration of sulfur oxides and dehydration of sulfur acids and present spectroscopic studies to document such effects. We investigate these reactions using FTIR and UV/Vis spectroscopy and will report on our findings.

  19. Distinct gut-derived lactic acid bacteria elicit divergent dendritic cell-mediated NK cell responses

    Fink, Lisbeth Nielsen; Zeuthen, Louise Hjerrild; Christensen, Hanne;

    2007-01-01

    Lactic acid bacteria (LAB) are abundant in the gastrointestinal tract where they continuously regulate the immune system. NK cells are potently activated by dendritic cells (DCs) matured by inflammatory stimuli, and NK cells are present in the gut epithelium and in mesenteric lymph nodes, but it is...

  20. ON THE PECULIARITIES OF THE RING CONTRACTION REACTIONS OF HOMODRIMANES VIA ACID MEDIATED EPOXIDE REARRANGEMENT

    Veaceslav Kulciţki

    2011-06-01

    Full Text Available A selective rearrangement of a epoxy-homodrimanic substrate is described. Using fluorosulfonic acid at low temperature leads by ring contraction to a perhydrindanic structure. On the contrary, using boron trifluoride-diethyl ether at r.t. selectively brings about angular methyl migration.

  1. The formation of an ordered microporous aluminum-based material mediated by phthalic acid.

    Zhang, Wei; Cai, Jian-Hua; Huang, Pei-Pei; Hu, Lin-Lin; Cao, An-Min; Wan, Li-Jun

    2016-06-28

    By using phthalic acid as a soft template, we showed that it was possible to prepare a microporous aluminum-based material when the precipitation of Al(3+) was properly controlled. We also identified that this microporous aluminum-based material could be promising for the removal of fluoride ions in water treatment. PMID:27263661

  2. PTH1 receptor is involved in mediating cellular response to long-chain polyunsaturated fatty acids.

    Jose Candelario

    Full Text Available The molecular pathways by which long chain polyunsaturated fatty acids (LCPUFA influence skeletal health remain elusive. Both LCPUFA and parathyroid hormone type 1 receptor (PTH1R are known to be involved in bone metabolism while any direct link between the two is yet to be established. Here we report that LCPUFA are capable of direct, PTH1R dependent activation of extracellular ligand-regulated kinases (ERK. From a wide range of fatty acids studied, varying in chain length, saturation, and position of double bonds, eicosapentaenoic (EPA and docosahexaenoic fatty acids (DHA caused the highest ERK phosphorylation. Moreover, EPA potentiated the effect of parathyroid hormone (PTH(1-34 in a superagonistic manner. EPA or DHA dependent ERK phosphorylation was inhibited by the PTH1R antagonist and by knockdown of PTH1R. Inhibition of PTH1R downstream signaling molecules, protein kinases A (PKA and C (PKC, reduced EPA and DHA dependent ERK phosphorylation indicating that fatty acids predominantly activate G-protein pathway and not the β-arrestin pathway. Using picosecond time-resolved fluorescence microscopy and a genetically engineered PTH1R sensor (PTH-CC, we detected conformational responses to EPA similar to those caused by PTH(1-34. PTH1R antagonist blocked the EPA induced conformational response of the PTH-CC. Competitive binding studies using fluorescence anisotropy technique showed that EPA and DHA competitively bind to and alter the affinity of PTH1 receptor to PTH(1-34 leading to a superagonistic response. Finally, we showed that EPA stimulates protein kinase B (Akt phosphorylation in a PTH1R-dependent manner and affects the osteoblast survival pathway, by inhibiting glucocorticoid-induced cell death. Our findings demonstrate for the first time that LCPUFAs, EPA and DHA, can activate PTH1R receptor at nanomolar concentrations and consequently provide a putative molecular mechanism for the action of fatty acids in bone.

  3. [Development of an ultrasound-mediated nucleic acid delivery system for treating muscular dystrophies].

    Negishi, Yoichi; Hamano, Nobuhito; Shiono, Hitomi; Akiyama, Saki; Endo-Takahashi, Yoko; Suzuki, Ryo; Maruyama, Kazuo; Aramaki, Yukihiko

    2012-01-01

    Muscular dystrophies are a group of heterogeneous diseases that are characterized by progressive muscle weakness, wasting and degeneration. These muscular deficiencies are often caused by the loss of the protein dystrophin, a crucial element of the dystrophin-glycoprotein complex of muscle fibers. Duchenne muscular dystrophy (DMD) is a fatal, X-linked muscular disease that occurs in 1 out of every 3500 males. Therefore, feasible strategies for replacing or repairing the defective gene are required; however, to date, no effective therapeutic strategies for muscular dystrophies have been established. In this review, we first introduce gene therapies mediated by adeno-associated viruses (AAVs) including a functional dystrophin cDNA or antisense oligonucleotide (AO)-induced exon-skipping therapies, which are designed to exclude the mutated or additional exon(s) in the defective gene and thereby correct the translational reading frame. Recently, we developed "Bubble liposomes" (BLs), which are polyethylene glycol (PEG)-modified liposomes entrapping echo-contrast gas that is known as ultrasound (US) imaging gas. BL application combined with US exposure can function as a novel gene delivery tool, and we demonstrate that the US-mediated eruption of BLs is a feasible and efficient technique to deliver plasmid DNA or AOs for the treatment of muscular dystrophies. PMID:23208045

  4. Incorporation of hyaluronic acid into collagen scaffolds for the control of chondrocyte-mediated contraction and chondrogenesis

    Tang Shunqing [Department of Biomedical Engineering, Jinan University, Guangzhou 510632 (China); Spector, Myron [Tissue Engineering, VA Boston Healthcare System, Boston, MA 02130 (United States)

    2007-09-15

    Hyaluronic acid (HA), a principal matrix molecule in many tissues, is present in high amounts in articular cartilage. HA contributes in unique ways to the physical behavior of the tissue, and has been shown to have beneficial effects on chondrocyte activity. The goal of this study was to incorporate graduated amounts of HA into type I collagen scaffolds for the control of chondrocyte-mediated contraction and chondrogenesis in vitro. The results demonstrated that the amount of contraction of HA/collagen scaffolds by adult canine articular chondrocytes increased with the HA content of the scaffolds. The greatest amount of chondrogenesis after two weeks was found in the scaffolds which had undergone the most contraction. HA can play a useful role in adjusting the mechanical behavior of tissue engineering scaffolds and chondrogenesis in chondrocyte-seeded scaffolds.

  5. Incorporation of hyaluronic acid into collagen scaffolds for the control of chondrocyte-mediated contraction and chondrogenesis

    Hyaluronic acid (HA), a principal matrix molecule in many tissues, is present in high amounts in articular cartilage. HA contributes in unique ways to the physical behavior of the tissue, and has been shown to have beneficial effects on chondrocyte activity. The goal of this study was to incorporate graduated amounts of HA into type I collagen scaffolds for the control of chondrocyte-mediated contraction and chondrogenesis in vitro. The results demonstrated that the amount of contraction of HA/collagen scaffolds by adult canine articular chondrocytes increased with the HA content of the scaffolds. The greatest amount of chondrogenesis after two weeks was found in the scaffolds which had undergone the most contraction. HA can play a useful role in adjusting the mechanical behavior of tissue engineering scaffolds and chondrogenesis in chondrocyte-seeded scaffolds

  6. Critical role of fatty acid metabolism in ILC2-mediated barrier protection during malnutrition and helminth infection.

    Wilhelm, Christoph; Harrison, Oliver J; Schmitt, Vanessa; Pelletier, Martin; Spencer, Sean P; Urban, Joseph F; Ploch, Michelle; Ramalingam, Thirumalai R; Siegel, Richard M; Belkaid, Yasmine

    2016-07-25

    Innate lymphoid cells (ILC) play an important role in many immune processes, including control of infections, inflammation, and tissue repair. To date, little is known about the metabolism of ILC and whether these cells can metabolically adapt in response to environmental signals. Here we show that type 2 innate lymphoid cells (ILC2), important mediators of barrier immunity, predominantly depend on fatty acid (FA) metabolism during helminth infection. Further, in situations where an essential nutrient, such as vitamin A, is limited, ILC2 sustain their function and selectively maintain interleukin 13 (IL-13) production via increased acquisition and utilization of FA. Together, these results reveal that ILC2 preferentially use FAs to maintain their function in the context of helminth infection or malnutrition and propose that enhanced FA usage and FA-dependent IL-13 production by ILC2 could represent a host adaptation to maintain barrier immunity under dietary restriction. PMID:27432938

  7. Electrons Mediate the Gas-Phase Oxidation of Formic Acid with Ozone.

    van der Linde, Christian; Tang, Wai-Kit; Siu, Chi-Kit; Beyer, Martin K

    2016-08-26

    Gas-phase reactions of CO3 (.-) with formic acid are studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Signal loss indicates the release of a free electron, with the formation of neutral reaction products. This is corroborated by adding traces of SF6 to the reaction gas, which scavenges 38 % of the electrons. Quantum chemical calculations of the reaction potential energy surface provide a reaction path for the formation of neutral carbon dioxide and water as the thermochemically favored products. From the literature, it is known that free electrons in the troposphere attach to O2 , which in turn transfer the electron to O3 . O3 (.-) reacts with CO2 to form CO3 (.-) . The reaction reported here formally closes the catalytic cycle for the oxidation of formic acid with ozone, catalyzed by free electrons. PMID:27400953

  8. Synthesis of acrylic acid derivatives from carbon dioxide and ethylene mediated by molecular nickel complexes

    Lee, Sin Ying Tina

    2013-01-01

    This work aimed at the synthesis of acrylic acid derivatives from ethylene and CO2 and well as the investigation of β-hydride elimination reaction of nickelalactones with methyl iodide and methyl triflate to form methyl acrylate. The oxidative coupling reaction of ethylene and CO2 on nickel center was ligand selective, and gave low yields of nickelalactone product at mild synthetic conditions. Key intermediates identified and characterized in the β-H elimination reaction provided rich insight...

  9. Exercise-mediated vasodilation in human obesity and metabolic syndrome: effect of acute ascorbic acid infusion

    Limberg, Jacqueline K.; Kellawan, J. Mikhail; Harrell, John W.; Johansson, Rebecca E.; Eldridge, Marlowe W.; Proctor, Lester T.; Sebranek, Joshua J.; Schrage, William G.

    2014-01-01

    We tested the hypothesis that infusion of ascorbic acid (AA), a potent antioxidant, would alter vasodilator responses to exercise in human obesity and metabolic syndrome (MetSyn). Forearm blood flow (FBF, Doppler ultrasound) was measured in lean, obese, and MetSyn adults (n = 39, 32 ± 2 yr). A brachial artery catheter was inserted for blood pressure monitoring and local infusion of AA. FBF was measured during dynamic handgrip exercise (15% maximal effort) with and without AA infusion. To acco...

  10. Nitrated fatty acids suppress angiotensin II-mediated fibrotic remodelling and atrial fibrillation

    Rudolph, T.K.; Ravekes, T.; Klinke, A.; Friedrichs, K.; Mollenhauer, M.; Pekarová, Michaela; Ambrožová, Gabriela; Martíšková, Hana; Kaur, J.J.; Matthes, B.; Schwoerer, A.; Woodcock, S.R.; Kubala, Lukáš; Freeman, B.A.; Baldus, S.; Rudolph, V.

    2016-01-01

    Roč. 109, č. 1 (2016), s. 174-184. ISSN 0008-6363 R&D Projects: GA ČR(CZ) GP13-40824P; GA MŠk(CZ) EE2.3.30.0030 Grant ostatní: GAAV(CZ) M200041208 Institutional support: RVO:68081707 Keywords : Atrial fibrillation * Fibrosis * Nitro-fatty acids Subject RIV: BO - Biophysics Impact factor: 5.940, year: 2014

  11. Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

    Yongjie Meng; Feng Chen; Haiwei Shuai; Xiaofeng Luo; Jun Ding; Shengwen Tang; Shuanshuan Xu; Jianwei Liu; Weiguo Liu; Junbo Du; Jiang Liu; Feng Yang; Xin Sun; Taiwen Yong; Xiaochun Wang

    2016-01-01

    Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interest...

  12. Deviant Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP)-mediated Ca2+ Signaling upon Lysosome Proliferation*

    Dickinson, G. D.; Churchill, G. C.; Brailoiu, E; Patel, S.

    2010-01-01

    Accumulating evidence suggests that the endolysosomal system is a novel intracellular Ca2+ pool mobilized by the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). Although lysosomes in neurons are known to proliferate in numerous neurodegenerative diseases and during the normal course of aging, little is known concerning the effect of lysosomal proliferation on Ca2+ homeostasis. Here, we induce proliferation of lysosomes in primary cultures of rat hippocampal neurons an...

  13. Lewis acid Mediated Aza-Diels-Alder Reactions and Asymmetric Alkylations of 2H-azirines

    Risberg, Erik

    2004-01-01

    This thesis describes the use of 2H-azirines, three-membered unsaturatednitrogen-containing heterocycles, as reactive intermediates ina number of Lewis acid promoted alkylations and Diels-Alderreactions providing synthetically useful aziridines. In order to carry out this investigation a new generalprocedure for the ring closure of vinyl azides, forming theresultant 3-substituted-2H-azirines, was developed applying low boiling solventsin closed reaction vessels at elevated temperatures. The a...

  14. Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

    Rao, A Veera Bhadra

    2016-01-01

    Summary A facile and modular synthesis of triarylmethanes was achieved in good yield via a two-step sequence in which the final step is the copper(II)-catalyzed arylation of diarylmethanols with arylboronic acids. By using this protocol a variety of symmetrical and unsymmetrical triarylmethanes were synthesized. As an application of the newly developed methodology, we demonstrate a high-yielding synthesis of the triarylmethane intermediate towards an anti-breast-cancer drug candidate. PMID:27340442

  15. Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways.

    Dyall, S C; Mandhair, H K; Fincham, R E A; Kerr, D M; Roche, M; Molina-Holgado, F

    2016-08-01

    Emerging evidence suggests a complex interplay between the endocannabinoid system, omega-3 fatty acids and the immune system in the promotion of brain self-repair. However, it is unknown if all omega-3 fatty acids elicit similar effects on adult neurogenesis and if such effects are mediated or regulated by interactions with the endocannabinoid system. This study investigated the effects of DHA and EPA on neural stem cell (NSC) fate and the role of the endocannabinoid signalling pathways in these effects. EPA, but not DHA, significantly increased proliferation of NSCs compared to controls, an effect associated with enhanced levels of the endocannabinoid 2-arachidonylglycerol (2-AG) and p-p38 MAPK, effects attenuated by pre-treatment with CB1 (AM251) or CB2 (AM630) receptor antagonists. Furthermore, in NSCs derived from IL-1β deficient mice, EPA significantly decreased proliferation and p-p38 MAPK levels compared to controls, suggesting a key role for IL-1β signalling in the effects observed. Although DHA similarly increased 2-AG levels in wild-type NSCs, there was no concomitant increase in proliferation or p-p38 MAPK activity. In addition, in NSCs from IL-1β deficient mice, DHA significantly increased proliferation without effects on p-P38 MAPK, suggesting effects of DHA are mediated via alternative signalling pathways. These results provide crucial new insights into the divergent effects of EPA and DHA in regulating NSC proliferation and the pathways involved, and highlight the therapeutic potential of their interplay with endocannabinoid signalling in brain repair. PMID:27044662

  16. Ferric ion mediated photochemical decomposition of perfluorooctanoic acid (PFOA) by 254 nm UV light

    The great enhancement of ferric ion on the photochemical decomposition of environmentally persistent perfluorooctanoic acid (PFOA) under 254 nm UV light was reported. In the presence of 10 μM ferric ion, 47.3% of initial PFOA (48 μM) was decomposed and the defluorination ratio reached 15.4% within 4 h reaction time. While the degradation and defluorination ratio greatly increased to 80.2% and 47.8%, respectively, when ferric ion concentration increased to 80 μM, and the corresponding half-life was shortened to 103 min. Though the decomposition rate was significantly lowered under nitrogen atmosphere, PFOA was efficiently decomposed too. Other metal ions like Cu2+ and Zn2+ also slightly improved the photochemical decomposition of PFOA under irradiation of 254 nm UV light. Besides fluoride ion, other intermediates during PFOA decomposition including formic acid and five shorter-chain perfluorinated carboxylic acids (PFCAs) with C7, C6, C5, C4 and C3, respectively, were identified and quantified by IC or LC/MS. The mixture of PFOA and ferric ion had strong absorption around 280 nm. It is proposed that PFOA coordinates with ferric ion to form a complex, and its excitation by 254 nm UV light leads to the decomposition of PFOA in a stepwise way

  17. Optimization of Lipase-Mediated Synthesis of 1-Nonene Oxide Using Phenylacetic Acid and Hydrogen Peroxide

    Mohd Basyaruddin Abdul Rahman

    2012-10-01

    Full Text Available Herein, an efficient epoxidation of 1-nonene is described. In a simple epoxidation system, commercially available Novozym 435, an immobilized Candida antarctica lipase B, and hydrogen peroxide (H2O2 were utilized to facilitate the in situ oxidation of phenylacetic acid to the corresponding peroxy acid which then reacted with 1-nonene to give 1-nonene oxide with high yield and selectivity. The aliphatic terminal alkene was epoxidised efficiently in chloroform to give an excellent yield (97%–99% under the optimum reaction conditions, including temperature (35 °C, initial H2O2 concentration (30%, H2O2 amount (4.4 mmol, H2O2 addition rate (one step, acid amount (8.8 mmol, and stirring speed (250 rpm. Interestingly, the enzyme was stable under the single-step addition of H2O2 with a catalytic activity of 190.0 Ug−1. The entire epoxidation process was carried out within 12 h using a conventional water bath shaker.

  18. Cathepsin D-mediated yolk protein degradation is blocked by acid phosphatase inhibitors.

    Fialho, Eliane; Nakamura, Angelica; Juliano, Luiz; Masuda, Hatisaburo; Silva-Neto, Mário A C

    2005-04-15

    Vitellin (VT) is a lipoglycophosphoprotein stored inside the eggs of every oviparous organism during oogenesis. In the blood-sucking bug Rhodnius prolixus, VT is deposited inside growing oocytes together with two acid hydrolases: acid phosphatase (AP) and cathepsin D (CD). Egg fertilization triggers AP activity and VT proteolysis in vivo [Insect Biochem. Mol. Biol. 2002 (32) 847]. Here, we show that CD is the main protease targeting VT proteolysis during egg development. CD activity in total egg homogenates is blocked by the classical aspartyl protease inhibitor, pepstatin A. Surprisingly, AP inhibitors such as NaF, Na+/K+ tartrate, and inorganic phosphate also block VT proteolysis, whereas this effect is not observed when tyrosine phosphatase inhibitors such as vanadate and phenylarsine oxide or an inhibitor of alkaline phosphatases such as levamisole are used in a VT proteolysis assay. NaF concentrations that block isolated AP activity do not affect the activity of partially purified CD. Therefore, a specific repressor of VT proteolysis must be dephosphorylated by AP in vivo. In conclusion, these results demonstrate for the first time that acid hydrolases act cooperatively to promote yolk degradation during egg development in arthropods. PMID:15797237

  19. A novel FADS1 isoform potentiates FADS2-mediated production of eicosanoid precursor fatty acids.

    Park, Woo Jung; Kothapalli, Kumar S D; Reardon, Holly T; Lawrence, Peter; Qian, Shu-Bing; Brenna, J Thomas

    2012-08-01

    The fatty acid desaturase (FADS) genes code for the rate-limiting enzymes required for the biosynthesis of long-chain polyunsaturated fatty acids (LCPUFA). Here we report discovery and function of a novel FADS1 splice variant. FADS1 alternative transcript 1 (FADS1AT1) enhances desaturation of FADS2, leading to increased production of eicosanoid precursors, the first case of an isoform modulating the enzymatic activity encoded by another gene. Multiple protein isoforms were detected in primate liver, thymus, and brain. In human neuronal cells, their expression patterns are modulated by differentiation and result in alteration of cellular fatty acids. FADS1, but not FADS1AT1, localizes to endoplasmic reticulum and mitochondria. Ribosomal footprinting demonstrates that all three FADS genes are translated at similar levels. The noncatalytic regulation of FADS2 desaturation by FADS1AT1 is a novel, plausible mechanism by which several phylogenetically conserved FADS isoforms may regulate LCPUFA biosynthesis in a manner specific to tissue, organelle, and developmental stage. PMID:22619218

  20. Phenylboronic acid-functionalized polyamidoamine-mediated Bcl-2 siRNA delivery for inhibiting the cell proliferation.

    Wu, Di; Yang, Jiebing; Xing, Zhen; Han, Haobo; Wang, Tingting; Zhang, Aijun; Yang, Yan; Li, Quanshun

    2016-10-01

    In this study, the conjugation of phenylboronic acid (PBA) to amine-terminated polyamidoamine (PAMAM) was successfully conducted to prepare a tumor-targeted gene carrier PBA-functionalized PAMAM (PPP) for Bcl-2 siRNA delivery, using a heterobifunctional crosslinker NHS-PEG5k-Mal. The carrier possessed favorable capacity for siRNA condensation and could protect siRNA from the degradation against RNase and serum. The introduction of PBA could facilitate the cellular uptake and further transfection of Bcl-2 siRNA demonstrated by confocal laser scanning microscopy and flow cytometry. Meanwhile, PPP-mediated transfection of Bcl-2 siRNA could significantly inhibit the expression of Bcl-2 gene at both mRNA and protein levels. Furthermore, owing to the knock-down of Bcl-2, PPP/siRNA could significantly inhibit the cell proliferation by inducing the cell apoptosis, and also enhance the antitumor efficiency of doxorubicin by suppressing the resistance of tumor cells to chemotherapeutics. In conclusion, the PPP-mediated Bcl-2 siRNA delivery could potentially be an effective platform for solving the drug resistance and further achieving the combined chemotherapy and gene therapy in tumor treatment. PMID:27371891

  1. A novel cisplatin mediated apoptosis pathway is associated with acid sphingomyelinase and FAS proapoptotic protein activation in ovarian cancer.

    Maurmann, L; Belkacemi, L; Adams, N R; Majmudar, P M; Moghaddas, S; Bose, R N

    2015-07-01

    Platinum-based anticancer drugs, including cisplatin and carboplatin, have been cornerstones in the treatment of solid tumors. We report here that these DNA-damaging agents, particularly cisplatin, induce apoptosis through plasma membrane disruption, triggering FAS death receptor via mitochondrial (intrinsic) pathways. Our objectives were to: quantify the composition of membrane metabolites; and determine the potential involvement of acid sphingomyelinase (ASMase) in the FAS-mediated apoptosis in ovarian cancer after cisplatin treatment. The resulting analysis revealed enhanced apoptosis as measured by: increased phosphocholine, and glycerophosphocholine; elevated cellular energetics; and phosphocreatine and nucleoside triphosphate concentrations. The plasma membrane alterations were accompanied by increased ASMase activity, leading to the upregulation of FAS, FASL and related pro-apoptotic BAX and PUMA genes. Moreover FAS, FASL, BAX, PUMA, CASPASE-3 and -9 proteins were upregulated. Our findings implicate ASMase activity and the intrinsic pathways in cisplatin-mediated membrane demise, and contribute to our understanding of the mechanisms by which ovarian tumors may become resistant to cisplatin. PMID:25846011

  2. Genetic interaction of two abscisic acid signaling regulators, HY5 and FIERY1, in mediating lateral root formation

    Chen, Hao

    2011-01-01

    Root architecture is continuously shaped in a manner that helps plants to better adapt to the environment. Gene regulation at the transcriptional or post-transcriptional levels largely controls this environmental response. Recently, RNA silencing has emerged as an important player in gene regulation and is involved in many aspects of plant development, including lateral root formation. In a recent study, we found that FIERY1, a bifunctional abiotic stress and abscisic acid (ABA) signaling regulator and an endogenous RNA silencing suppressor, mediates auxin response during lateral root formation in Arabidopsis. We proposed that FRY1 regulates lateral root development through its activity on adenosine 3,5-bisphosphate (PAP), a strong inhibitor of exoribonucleases (XRNs). Interestingly, some of the phenotypes of fry1, such as enhanced response to light in repressing hypocotyl elongation and hypersensitivity to ABA in lateral root growth, are opposite to those of another light- and ABA-signaling mutant, hy5. Here we analyzed the hy5 fry1 double mutant for root and hypocotyl growth. We found that the hy5 mutation can suppress the enhanced light sensitivity in fry1 hypocotyl elongation and restore the lateral root formation. The genetic interaction between HY5 and FRY1 indicates that HY5 and FRY1 may act in overlapping pathways that mediate light signaling and lateral root development. © 2011 Landes Bioscience.

  3. A family of conserved bacterial effectors inhibits salicylic acid-mediated basal immunity and promotes disease necrosis in plants.

    DebRoy, Sruti; Thilmony, Roger; Kwack, Yong-Bum; Nomura, Kinya; He, Sheng Yang

    2004-06-29

    Salicylic acid (SA)-mediated host immunity plays a central role in combating microbial pathogens in plants. Inactivation of SA-mediated immunity, therefore, would be a critical step in the evolution of a successful plant pathogen. It is known that mutations in conserved effector loci (CEL) in the plant pathogens Pseudomonas syringae (the Delta CEL mutation), Erwinia amylovora (the dspA/E mutation), and Pantoea stewartii subsp. stewartii (the wtsE mutation) exert particularly strong negative effects on bacterial virulence in their host plants by unknown mechanisms. We found that the loss of virulence in Delta CEL and dspA/E mutants was linked to their inability to suppress cell wall-based defenses and to cause normal disease necrosis in Arabidopsis and apple host plants. The Delta CEL mutant activated SA-dependent callose deposition in wild-type Arabidopsis but failed to elicit high levels of callose-associated defense in Arabidopsis plants blocked in SA accumulation or synthesis. This mutant also multiplied more aggressively in SA-deficient plants than in wild-type plants. The hopPtoM and avrE genes in the CEL of P. syringae were found to encode suppressors of this SA-dependent basal defense. The widespread conservation of the HopPtoM and AvrE families of effectors in various bacteria suggests that suppression of SA-dependent basal immunity and promotion of host cell death are important virulence strategies for bacterial infection of plants. PMID:15210989

  4. Fumaric acid esters prevent the NLRP3 inflammasome-mediated and ATP-triggered pyroptosis of differentiated THP-1 cells.

    Miglio, Gianluca; Veglia, Eleonora; Fantozzi, Roberto

    2015-09-01

    Fumaric acid esters (FAEs) exert therapeutic effects in patients with psoriasis and multiple sclerosis, however their mode of action remains elusive. Pyroptosis is a caspase-1-dependent pro-inflammatory form of programmed cell death, mediated by the activation of inflammasomes. To understand the pharmacological basis of the therapeutic effects of FAEs, the anti-pyroptotic activity of dimethyl fumarate (DMF) and its hydrolysis metabolite monomethyl fumarate (MMF) was studied in a model of NLRP3 inflammasome-mediated pyroptosis of human macrophages. Phorbol myristate acetate-differentiated THP-1 cells were exposed to lipopolysaccharide (5 μg/ml; 4h), then pulsed with ATP (5mM; 1h). MMF, DMF, or parthenolide (positive control) were added 1h before the ATP pulse. The pyroptotic cell death was evaluated by morphological examination and quantified by measuring the lactate dehydrogenase leakage. The ATP-triggered death of THP-1 cells (60.4 ± 4.0%) was significantly (Pmolecular cascade leading to cell death. These results indicate that FAEs are endowed with anti-pyroptotic activity, which may contribute to their therapeutic effects. PMID:26096886

  5. Association of serum aryl hydrocarbon receptor activity and RBC omega-3 polyunsaturated fatty acids with flow-mediated dilation in healthy, young Hispanic cigarette smokers

    Wiest, Elani F.; Warneke, Alex; Walsh, Mary T.; Langsfeld, Mark; Anderson, Joe; Walker, Mary K

    2014-01-01

    Impaired flow-mediated dilation (FMD) occurs prior to clinical disease in young cigarette smokers. We investigated two potential biomarkers of FMD: serum aryl hydrocarbon receptor (AHR) activity and RBC omega-3 polyunsaturated fatty acids in healthy young Hispanic cigarette smokers. We recruited never (n = 16) and current (n = 16) Hispanic smokers (32 ± 7 years old), excluding individuals with clinical cardiovascular disease. We measured FMD with duplex ultrasound, RBC fatty acids and serum A...

  6. Decreased apoptosis during CAR-mediated hepatoprotection against lithocholic acid-induced liver injury in mice.

    Beilke, Lisa D; Aleksunes, Lauren M; Olson, Erik R; Besselsen, David G; Klaassen, Curtis D; Dvorak, Katerina; Cherrington, Nathan J

    2009-07-10

    Myeloid cell leukemia-1 (Mcl-1) is an anti-apoptotic protein that is regulated by the constitutive androstane receptor (CAR). Activation of CAR can protect the liver against bile acid-induced toxicity and it may have a role in cell death via apoptosis by altering expression of Bcl-2 family proteins such as myeloid cell leukemia-1 (Mcl-1). Our aim was to determine if activation of CAR reduces hepatocellular apoptosis during cholestasis as a mechanism of hepatoprotection. CAR(+/+) (WT) and CAR(-/-) (CAR-null) mice were pre-treated with compounds known to activate CAR prior to induction of intrahepatic cholestasis using the secondary bile acid lithocholic acid (LCA). Pre-treatment with the CAR activators phenobarbital (PB) and TCPOBOP (TC), as well as the non-CAR activator pregnenolone 16alpha-carbontrile (PCN), protected against LCA-induced liver injury in WT mice, whereas liver injury was more extensive without CAR (CAR-null). Unexpectedly, expression of anti-apoptotic Mcl-1 and Bcl-x(L) was not increased in hepatoprotected mice. Compared to unprotected groups, apoptosis was decreased in hepatoprotected mice as evidenced by the absence of cleaved caspase 3 (cCasp3). In contrast to the cytoplasmic localization in the injured livers (LCA and oltipraz), Mcl-1 protein was localized in the nucleus of hepatoprotected livers to potentially promote cell survival. This study demonstrates that although apoptosis is reduced in hepatoprotected mice pre-treated with CAR and non-CAR activators; hepatoprotection is not directly a result of CAR-induced Mcl-1 expression. PMID:19433268

  7. Gamma-aminobutyric acid (GABA) and neuropeptides in neural areas mediating motion-induced emesis

    Damelio, F.; Daunton, Nancy G.; Fox, Robert A.

    1991-01-01

    Immunocytochemical methods were employed to localize the neurotransmitter amino acid gamma-aminobutyric acid and the neuropeptides substance P and Met-enkephalin in the area postrema (AP), area subpostrema (ASP), nucleus of the tractus solitarius (NTS), dorsal motor nucleus of the vagus nerve (DMNV), and lateral vestibular nucleus (LVN). Glutamic acid decarboxylase immunoreactive (GAD-IR) terminals and fibers were observed in the AP and particularly in the ASP. A gradual decrease in the density of terminals was seen towards the solitary complex. The DMNV revealed irregularly scattered GAD-IR terminals within the neuropil or closely surrounding neuronal cell bodies. The LVN, particularly the dorsal division, showed numerous axon terminals which were mostly localize around large neurons and their proximal dendrites. Substance P immunoreactive (SP-IR) terminals and fibers showed high density in the solitary complex, in particular within the lateral division. The ASP showed medium to low density of SP-IR fibers and terminals. The AP exhibited a small number of fibers and terminals irregularly distributed. The DMNV revealed a high density of SP-IR terminals and fibers that were mainly concentrated in the periphery. Very few terminals were detected in the LVN. Met-enkephalin immunoreactive (Met-Enk-IR) fibers and terminals showed high density and uniform distribution in the DMNV. Scattered terminals and fibers were observed in the AP, ASP, and NTS (particularly the lateral division). The very few fibers were observed in the LVN surrounded the neuronal cell bodies. The present report is part of a study designed to investigate the interaction between neuropeptides and conventional neurotransmitters under conditions producing motion sickness and in the process of sensory-motor adaptation.

  8. PGC-1α-mediated branched-chain amino acid metabolism in the skeletal muscle.

    Yukino Hatazawa

    Full Text Available Peroxisome proliferator-activated receptor (PPAR γ coactivator 1α (PGC-1α is a coactivator of various nuclear receptors and other transcription factors, which is involved in the regulation of energy metabolism, thermogenesis, and other biological processes that control phenotypic characteristics of various organ systems including skeletal muscle. PGC-1α in skeletal muscle is considered to be involved in contractile protein function, mitochondrial function, metabolic regulation, intracellular signaling, and transcriptional responses. Branched-chain amino acid (BCAA metabolism mainly occurs in skeletal muscle mitochondria, and enzymes related to BCAA metabolism are increased by exercise. Using murine skeletal muscle overexpressing PGC-1α and cultured cells, we investigated whether PGC-1α stimulates BCAA metabolism by increasing the expression of enzymes involved in BCAA metabolism. Transgenic mice overexpressing PGC-1α specifically in the skeletal muscle had increased the expression of branched-chain aminotransferase (BCAT 2, branched-chain α-keto acid dehydrogenase (BCKDH, which catabolize BCAA. The expression of BCKDH kinase (BCKDK, which phosphorylates BCKDH and suppresses its enzymatic activity, was unchanged. The amount of BCAA in the skeletal muscle was significantly decreased in the transgenic mice compared with that in the wild-type mice. The amount of glutamic acid, a metabolite of BCAA catabolism, was increased in the transgenic mice, suggesting the activation of muscle BCAA metabolism by PGC-1α. In C2C12 cells, the overexpression of PGC-1α significantly increased the expression of BCAT2 and BCKDH but not BCKDK. Thus, PGC-1α in the skeletal muscle is considered to significantly contribute to BCAA metabolism.

  9. DECREASED APOPTOSIS DURING CAR-MEDIATED HEPATOPROTECTION AGAINST LITHOCHOLIC ACID-INDUCED LIVER INJURY IN MICE

    Beilke, Lisa D.; Aleksunes, Lauren M.; Olson, Erik R.; Besselsen, David G; Klaassen, Curtis D.; Dvorak, Katerina; Cherrington, Nathan J.

    2009-01-01

    Myeloid cell leukemia-1 (Mcl-1) is an anti-apoptotic protein that is regulated by the constitutive androstane receptor (CAR). Activation of CAR can protect the liver against bile acid-induced toxicity and it may have a role in cell death via apoptosis by altering expression of Bcl-2 family proteins such as myeloid cell leukemia-1 (Mcl-1). Our aim was to determine if activation of CAR reduces hepatocellular apoptosis during cholestasis as a mechanism of hepatoprotection. CAR+/+ (WT) and CAR−/−...

  10. Surface-mediated nucleation in the solid-state polymorph transformation of terephthalic acid.

    Beckham, Gregg T; Peters, Baron; Starbuck, Cindy; Variankaval, Narayan; Trout, Bernhardt L

    2007-04-18

    A molecular mechanism for nucleation for the solid-state polymorph transformation of terephthalic acid is presented. New methods recently developed in our group, aimless shooting and likelihood maximization, are employed to construct a model for the reaction coordinate for the two system sizes studied. The reaction coordinate approximation is validated using the committor probability analysis. The transformation proceeds via a localized, elongated nucleus along the crystal edge formed by fluctuations in the supramolecular synthons, suggesting a nucleation and growth mechanism in the macroscopic system. PMID:17385859

  11. Production of phosphatidylcholine containing conjugated linoleic acid mediated by phospholipase A2

    Yamamoto, Yukihiro; Hosokawa, Masashi; Miyashita, Kazuo

    2006-01-01

    Esterification of lysophosphatidylcholine (LPC) with conjugated linoleic acid (CLA) was carried out using porcine pancreatic phospholipase A2 (PLA2). PLA2 only slightly synthesized phosphatidylcholine containing CLA (CLA-PC) at 2.6% by the addition of water. Addition of formamide in place of water markedly increased the yield of CLA-PC. In addition, synthesis of CLA-PC by PLA2 was affected by the amount of substrate CLA and PLA2 in the reaction system. Under optimal reaction conditions using ...

  12. PEPT2-mediated transport of 5-aminolevulinic acid and carnosine in astrocytes

    Xiang, Jianming; Hu, Yongjun; Smith, David E.; Keep, Richard F

    2006-01-01

    5-Aminolevulinic acid (ALA) and carnosine have important physiological and pathophysiological roles in the CNS. Both are substrates for the proton-coupled oligopeptide transporter PEPT2. The purpose of the current study was to determine the importance of PEPT2 in the uptake of ALA and carnosine in rat and mouse (PEPT2+/+ and PEPT2−/−) cultured neonatal astrocytes. Although neonatal astrocytes are known to express PEPT2, its quantitative importance in the transport of these compounds is not kn...

  13. Cullin 3 mediates SRC-3 ubiquitination and degradation to control the retinoic acid response

    Ferry, Christine; Gaouar, Samia; Fischer, Benoit; Boeglin, Marcel; Paul, Nicodeme; Samarut, Eric; Piskunov, Aleksandr; Pankotai-Bodo, Gabriella; Brino, Laurent; Rochette-Egly, Cecile

    2011-01-01

    SRC-3 is an important coactivator of nuclear receptors including the retinoic acid (RA) receptor α. Most of SRC-3 functions are facilitated by changes in the posttranslational code of the protein that involves mainly phosphorylation and ubiquitination. We recently reported that SRC-3 is degraded by the proteasome in response to RA. Here, by using an RNAi E3-ubiquitin ligase entry screen, we identified CUL-3 and RBX1 as components of the E3 ubiquitin ligase involved in the RA-induced ubiquitin...

  14. Fatty Acid Synthase Mediates the Epithelial-Mesenchymal Transition of Breast Cancer Cells

    Li, Junqin; Dong, Lihua; Wei, Dapeng; Wang, Xiaodong; Zhang, Shuo; Li, Hua

    2014-01-01

    This study aimed to investigate the role of fatty acid synthase (FASN) in the epithelial-mesenchymal transition (EMT) of breast cancer cells. MCF-7 cells and MCF-7 cells overexpressing mitogen-activated protein kinase 5 (MCF-7-MEK5) were used in this study. MCF-7-MEK5 cells showed stable EMT characterized by increased vimentin and decreased E-cadherin expression. An In vivo animal model was established using the orthotopic injection of MCF-7 or MCF-7-MEK5 cells. Real-time quantitative PCR and...

  15. Chlorogenic acid suppresses interleukin-1β-induced inflammatory mediators in human chondrocytes

    Chen, Wei-Ping; Wu, Li-Dong

    2014-01-01

    We investigated the anti-inflammatory properties of chlorogenic acid (CGA) in interleukin-1β-induced chondrocytes. The nitric oxide (NO) and prostaglandin E2 (PGE2) were detected by Griess and Enzyme-linked immunosorbent assay (ELISA) respectively. Quantitative real-time PCR and western blot were performed to measure the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2. Our results indicate that CGA inhibited the production of NO and PGE2 as well as the expression of iNOS...

  16. Evidence for 4-chlorobenzoic acid dehalogenation mediated by plasmids related to pSS50. [Alcaligenes

    Layton, A.C.; Sanseverino, J.; Wallace, W.; Corcoran, C.; Sayler, G.S. (Univ. of Tennessee, Knoxville (United States))

    1992-01-01

    The potential for polychlorinated biphenyl biodegradation is of environmental interest because of the toxicity and bioaccumulation of these compounds. Biodegradation studies on 4-chlorobiphenyl (4CB), a model for polychlorinated biphenyl degradation, have focused mainly on the genes and enzymes that permit the degradation of 4CB to 4-chlorobenzoate (4CBA). Most biphenyl- and polychlorinated biphenyl-degrading strains accumulate the corresponding chlorobenzoic acids without degrading the chlorobenzoate to CO{sub 2}. The study demonstrated that the 4-chlorobiphenyl-degrading Alcaligenes sp. strain ALP83 can degrade 4-chlorobenzoate to 4-hydroxybenzoate. The dehalogenase activity is correlated with a 10-kb fragment carried on plasmid pSS70.

  17. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture.

    Ramazan Kurt

    Full Text Available Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α-based combination therapy in chronic hepatitis C virus (HCV infection. Previously, we reported that free fatty acid (FFA-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1, which is why the antiviral activity of IFN-α against HCV is impaired.To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment.HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate and unsaturated (oleate long-chain free fatty acids (FFA. Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α and Type III IFN (IFN-λ was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA in the FFA-treated HCV cell culture model was investigated.FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ, which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA-treated cell culture

  18. Dorsal column inhibition of nociceptive thalamic cells mediated by gamma-aminobutyric acid mechanisms in the cat.

    Olausson, B; Xu, Z Q; Shyu, B C

    1994-11-01

    Cells in posterior parts of the cat thalamus were investigated. Responses in single units excited by electrical stimulation in the lateral funiculus (LF), the dorsal column nucleus (DCN) or the canine tooth pulp (TP) were analysed. All cells had a spontaneous resting activity which could be increased by extracellular iontophoretic application of DL-homocysteic acid (DLH) and decreased by gamma-aminobutyric acid (GABA). No effect on the spontaneous firing rate was observed following iontophoresis of the selective GABA-antagonists, picrotoxin (GABA-A receptor antagonist) or saclofen (GABA-B receptor antagonist). However, the decreased firing following GABA application was partially blocked by picrotoxin but not by saclofen. A phasic inhibition induced by DCN stimulation in nociceptive thalamic cells is indicated since simultaneous administration of picrotoxin increased the evoked response. This type of inhibitory mechanism could not be detected following LF or TP stimulation. The extracellular activity evoked by electrical stimulation of LF or TP was significantly depressed by preceding electrical stimulation in the DCN. This inhibition was reversed by simultaneous administration of picrotoxin, indicating an involvement of GABA-A receptors. The reversal of the DCN-induced depression of the late responses following LF stimulation occurred after application of saclofen. It is suggested that this effect is partly mediated via GABA-B receptors. Results from the present study indicate an interaction in the thalamus between presumed low-threshold (DCN) and presumed nociceptive afferents (LF and TP) similar to that previously described in the spinal cord. PMID:7872001

  19. Current concepts on the physiology and genetics of neurotransmitters-mediating enzyme-aromatic L-amino acid decarboxylase

    Two most important neurotransmitters, dopamine and serotonin are mediated by the enzyme aromatic L-amino acid decarboxylase (AADC). Because of their importance in the regulation of neuronal functions, behaviour and emotion of higher animals, many researchers are working on this enzyme to elucidate its physiological properties, structure and genetic aspects. We have discovered this enzyme in the mammalian blood, we established sensitive assay methods for the assay of the activities of this enzyme. We have made systematic studies on this enzyme in the tissues and brains of rats, and human subjects. We have found an endogenous inhibitor of this enzyme in the monkey's blood. The amino acid sequences of human AADC has been compared to rat or bovine. A full-length cDNA clone encoding human AADC has been isolated. Very recently the structure of human AADC gene including 5'-flaking region has been characterized and the transcriptional starting point has been determined. The human AADC gene assigned to chromosome 7. Up-to-date research data have shown that AADC is encoded by a single gene. Recently two patients with AADC deficiency were reported. This paper describes the systematic up-to-date review studies on AADC. (author). 62 refs, 5 figs, 8 tabs

  20. Rupestonic acid derivative YZH-106 suppresses influenza virus replication by activation of heme oxygenase-1-mediated interferon response.

    Ma, Lin-Lin; Wang, Hui-Qiang; Wu, Ping; Hu, Jin; Yin, Jin-Qiu; Wu, Shuo; Ge, Miao; Sun, Wen-Fang; Zhao, Jiang-Yu; Aisa, Haji Akber; Li, Yu-Huan; Jiang, Jian-Dong

    2016-07-01

    Given the limitation of available antiviral drugs and vaccines, there remains to be a pressing need for novel anti-influenza drugs. Rupestonic acid derivatives were reported to have an anti-influenza virus activity, but their mechanism remains to be elucidated. Herein, we aim to evaluate the antiviral activity of YZH-106, a rupestonic acid derivative, against a broad-spectrum of influenza viruses and to dissect its antiviral mechanisms. Our results demonstrated that YZH-106 exhibited a broad-spectrum antiviral activity against influenza viruses, including drug-resistant strains in vitro. Furthermore, YZH-106 provided partial protection of the mice to Influenza A virus (IAV) infection, as judged by decreased viral load in lungs, improved lung pathology, reduced body weight loss and partial survival benefits. Mechanistically, YZH-106 induced p38 MAPK and ERK1/2 phosphorylation, which led to the activation of erythroid 2-related factor 2 (Nrf2) that up-regulated heme oxygenase-1 (HO-1) expression in addition to other genes. HO-1 inhibited IAV replication by activation of type I IFN expression and subsequent induction of IFN-stimulated genes (ISGs), possibly in a HO-1 enzymatic activity-independent manner. These results suggest that YZH-106 inhibits IAV by up-regulating HO-1-mediated IFN response. HO-1 is thus a promising host target for antiviral therapeutics against influenza and other viral infectious diseases. PMID:27107768

  1. Acid-mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

    Katsunori Tanaka

    2009-08-01

    Full Text Available Microfluidic conditions were applied to acid-mediated reactions, namely, glycosylation, reductive opening of the benzylidene acetal groups, and dehydration, which are the keys to the practical synthesis of N-glycans and the immunostimulating natural product, pristane. A distinctly different reactivity from that in conventional batch stirring was found; the vigorous micromixing of the reactants with the concentrated acids is critical especially for the “fast” reactions to be successful. Such a common feature might be due to the integration of all favorable aspects of microfluidic conditions, i.e., efficient mixing, precise temperature control, and the easy handling of the reactive intermediate by controlling the residence time. The microfluidic reactions cited in this review indicate the need to reinvestigate the traditional or imaginary reactions which have so far been performed and evaluated only in batch apparatus, and therefore they could be recognized as a new strategy in synthesizing natural products of prominent biological activity in a “practical” and a “industrial” manner.

  2. Label-free electrochemical nucleic acid biosensing by tandem polymerization and cleavage-mediated cascade target recycling and DNAzyme amplification.

    Liu, Shufeng; Gong, Hongwei; Wang, Yanqun; Wang, Li

    2016-03-15

    Owing to the intrinsic importance of nucleic acid as bio-targets, the achievement of its simple and sensitive detection with high confidence is very essential for biological studies and diagnostic purposes. Herein, a label-free, isothermal, and ultrasensitive electrochemical detection of target DNA was developed by using a tandem polymerization and cleavage-mediated cascade target recycling and DNAzyme releasing amplification strategy. Upon sensing of the nucleic acid analyte for the assembled hairpin-like probe DNA on the electrode, the DNA polymerase guided the target recycling and simultaneously triggered the lambda exonuclease cleavage, accompanied by the cascade recycling of the released new complementary strand and the amplified liberation of the G-rich sequence of the HRP-mimicking DNAzyme. The electrocatalytic reduction of H2O2 by the generated hemin/G-quadruplex DNAzyme was used for the signal readout and further amplification toward target response. Such tandem functional operation by DNA polymerase, lambda exonuclease and DNAzyme endows the developed biosensor with a high sensitivity and also a high confidence. A low detection limit of 5 fM with an excellent selectivity toward target DNA could be achieved. It also exhibits the distinct advantages of simplicity in probe design and biosensor fabrication, and label-free electrochemical detection, thus may offer a promising avenue for the applications in disease diagnosis and clinical biomedicine. PMID:26513289

  3. Do sensory neurons mediate adaptive cytoprotection of gastric mucosa against bile acid injury?

    Mercer, D W; Ritchie, W P; Dempsey, D T

    1992-01-01

    Pretreatment with the mild irritant 1 mmol acidified taurocholate protects the gastric mucosa from the injury induced by the subsequent application of 5 mmol acidified taurocholate, a phenomenon referred to as "adaptive cytoprotection." How this occurs remains an enigma. The purpose of this study was to investigate the role of sensory neurons and mucus secretion in this phenomenon. Prior to injury with 5 mmol acidified taurocholate (pH 1.2), the stomachs of six groups of rats were subjected to the following protocol. Two groups were topically pretreated with either saline or the mild irritant 1 mmol acidified taurocholate. Two other groups received the topical anesthetic 1% lidocaine prior to pretreatment with either saline or 1 mmol acidified taurocholate. The last two groups got the mucolytic agent 10% N-acetylcysteine (NAC) after pretreatment with either saline or 1 mmol acidified taurocholate. Injury was assessed by measuring net transmucosal ion fluxes, luminal appearance of deoxyribonucleic acid (DNA), and gross and histologic injury. Pretreatment with the mild irritant 1 mmol acidified taurocholate significantly decreased bile acid-induced luminal ion fluxes and DNA accumulation, suggesting mucosal protection (corroborated by gross and histologic injury analysis). This effect was negated by lidocaine but not by NAC. Thus, it appears that sensory neurons, and not increased mucus secretion, play a critical role in adaptive cytoprotection. PMID:1733359

  4. Salt-mediated self-assembly of thioctic acid on gold nanoparticles.

    Volkert, Anna A; Subramaniam, Varuni; Ivanov, Michael R; Goodman, Amanda M; Haes, Amanda J

    2011-06-28

    Self-assembled monolayer (SAM) modification is a widely used method to improve the functionality and stability of bulk and nanoscale materials. For instance, the chemical compatibility and utility of solution-phase nanoparticles are often improved using covalently bound SAMs. Herein, solution-phase gold nanoparticles are modified with thioctic acid SAMs in the presence and absence of salt. Molecular packing density on the nanoparticle surfaces is estimated using X-ray photoelectron spectroscopy and increases by ∼20% when molecular self-assembly occurs in the presence versus the absence of salt. We hypothesize that as the ionic strength of the solution increases, pinhole and collapsed-site defects in the SAM are more easily accessible as the electrostatic interaction energy between adjacent molecules decreases, thereby facilitating the subsequent assembly of additional thioctic acid molecules. Significantly, increased SAM packing densities increase the stability of functionalized gold nanoparticles by a factor of 2 relative to nanoparticles functionalized in the absence of salt. These results are expected to improve the reproducible functionalization of solution-phase nanomaterials for various applications. PMID:21524135

  5. Precision microbiome reconstitution restores bile acid mediated resistance to Clostridium difficile

    Buffie, Charlie G.; Bucci, Vanni; Stein, Richard R.; McKenney, Peter T.; Ling, Lilan; Gobourne, Asia; No, Daniel; Liu, Hui; Kinnebrew, Melissa; Viale, Agnes; Littmann, Eric; van den Brink, Marcel R. M.; Jenq, Robert R.; Taur, Ying; Sander, Chris; Cross, Justin R.; Toussaint, Nora C.; Xavier, Joao B.; Pamer, Eric G.

    2015-01-01

    The gastrointestinal tracts of mammals are colonized by hundreds of microbial species that contribute to health, including colonization resistance against intestinal pathogens. Many antibiotics destroy intestinal microbial communities and increase susceptibility to intestinal pathogens. Among these, Clostridium difficile, a major cause of antibiotic-induced diarrhoea, greatly increases morbidity and mortality in hospitalized patients. Which intestinal bacteria provide resistance to C. difficile infection and their in vivo inhibitory mechanisms remain unclear. Here we correlate loss of specific bacterial taxa with development of infection, by treating mice with different antibiotics that result in distinct microbiota changes and lead to varied susceptibility to C. difficile. Mathematical modelling augmented by analyses of the microbiota of hospitalized patients identifies resistance-associated bacteria common to mice and humans. Using these platforms, we determine that Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium, is associated with resistance to C. difficile infection and, upon administration, enhances resistance to infection in a secondary bile acid dependent fashion. Using a workflow involving mouse models, clinical studies, metagenomic analyses, and mathematical modelling, we identify a probiotic candidate that corrects a clinically relevant microbiome deficiency. These findings have implications for the rational design of targeted antimicrobials as well as microbiome-based diagnostics and therapeutics for individuals at risk of C. difficile infection.

  6. Lipoxygenase-mediated pro-radical effect of melatonin via stimulation of arachidonic acid metabolism

    We have shown that melatonin immediately and transiently stimulates intracellular free radical production on a set of leukocytes, possibly as a consequence of calmodulin binding. We show here that melatonin-induced ROS are produced by lipoxygenase (LOX), since they are prevented by a set of LOX inhibitors, and are accompanied by increase of the 5-LOX product 5-HETE. LOX activation is accompanied by strong liberation of AA; inhibition of Ca2+-independent, but not Ca2+-dependent, phospholipase A2 (PLA2), prevents both melatonin-induced arachidonic acid and ROS production, whereas LOX inhibition only prevents ROS, indicating that PLA2 is upstream with respect to LOX, as occurs in many signaling pathways. Chlorpromazine, an inhibitor of melatonin-calmodulin interaction, inhibits both ROS and arachidonic acid production, thus possibly placing calmodulin at the origin of a melatonin-induced pro-radical pathway. Interestingly, it is known that Ca2+-independent PLA2 binds to calmodulin: our results are compatible with PLA2 being liberated by melatonin from a steady-state calmodulin sequestration, thus initiating an arachidonate signal transduction. These results delineate a novel molecular pathway through which melatonin may participate to the inflammatory response.

  7. Controllably local gene delivery mediated by polyelectrolyte multilayer films assembled from gene-loaded nanopolymersomes and hyaluronic acid

    Teng W

    2014-10-01

    a complex form. In vitro cell experiments demonstrate that PEM films can enhance the adhesion and proliferation of MSCs and efficiently transfect MSCs in situ in vitro for at least 4 days. Our results suggest that a (pNPs/HAn system can mediate efficient transfection in stem cells in a spatially and temporally controllable pattern, highlighting its huge potential in local gene therapy. Keywords: localized gene delivery, layer-by-layer self-assembly, gene-loaded nanopolymersomes, hyaluronic acid, polyelectrolyte multilayer films, mesenchymal stem cells

  8. Antisense-mediated suppression of C-hordein biosynthesis in the barley grain results in correlated changes in the transcriptome, protein profile, and amino acid composition

    Hansen, Mette; Lange, Marianne; Friis, Carsten;

    2007-01-01

    Antisense- or RNAi-mediated suppression of the biosynthesis of nutritionally inferior storage proteins is a promising strategy for improving the amino acid profile of seeds. However, the potential pleiotropic effects of this on interconnected pathways and the agronomic quality traits need to be...

  9. Charge-transfer interaction mediated organogels from 18β-glycyrrhetinic acid appended pyrene

    Jun Hu

    2013-12-01

    Full Text Available We describe herein the two-component charge-transfer (CT interaction induced organogel formation with 18β-glycyrrhetinic acid appended pyrene (GA-pyrene, 3 as the donor, and 2,4,7-trinitrofluorenone (TNF, 4 as the acceptor. The use of TNF (4 as a versatile electron acceptor in the formation of CT gels is demonstrated through the formation of gels in a variety of solvents. Thermal stability, stoichiometry, scanning electron microscopy (SEM, optical micrographs, and circular dichroism (CD are performed on these CT gels to investigate their thermal and assembly properties. UV–vis, fluorescence, mass spectrometric as well as variable-temperature 1H NMR experiments on these gels suggest that the CT interaction is one of the major driving forces for the formation of these organogels.

  10. Ultramild protein-mediated click chemistry creates efficient oligonucleotide probes for targeting and detecting nucleic acids

    Nåbo, Lina J.; Madsen, Charlotte Stahl; Jensen, Knud Jørgen;

    2015-01-01

    Functionalized synthetic oligonucleotides are finding growing applications in research, clinical studies, and therapy. However, it is not easy to prepare them in a biocompatible and highly efficient manner. We report a new strategy to synthesize oligonucleotides with promising nucleic acid...... targeting and detection properties. We focus in particular on the pH sensitivity of these new probes and their high target specificity. For the first time, human copper(I)-binding chaperon Cox17 was applied to effectively catalyze click labeling of oligonucleotides. This was performed under ultramild...... conditions with fluorophore, peptide, and carbohydrate azide derivatives. In thermal denaturation studies, the modified probes showed specific binding to complementary DNA and RNA targets. Finally, we demonstrated the pH sensitivity of the new rhodamine-based fluorescent probes in vitro and rationalize our...

  11. Cullin 3 mediates SRC-3 ubiquitination and degradation to control the retinoic acid response

    Ferry, Christine; Gaouar, Samia; Fischer, Benoit; Boeglin, Marcel; Paul, Nicodeme; Samarut, Eric; Piskunov, Aleksandr; Pankotai-Bodo, Gabriella; Brino, Laurent; Rochette-Egly, Cecile

    2011-01-01

    SRC-3 is an important coactivator of nuclear receptors including the retinoic acid (RA) receptor α. Most of SRC-3 functions are facilitated by changes in the posttranslational code of the protein that involves mainly phosphorylation and ubiquitination. We recently reported that SRC-3 is degraded by the proteasome in response to RA. Here, by using an RNAi E3-ubiquitin ligase entry screen, we identified CUL-3 and RBX1 as components of the E3 ubiquitin ligase involved in the RA-induced ubiquitination and subsequent degradation of SRC-3. We also show that the RA-induced ubiquitination of SRC-3 depends on its prior phosphorylation at serine 860 that promotes binding of the CUL-3–based E3 ligase in the nucleus. Finally, phosphorylation, ubiquitination, and degradation of SRC-3 cooperate to control the dynamics of transcription. In all, this process participates to the antiproliferative effect of RA. PMID:22147914

  12. Extended Electron-Transfer in Animal Cryptochromes Mediated by a Tetrad of Aromatic Amino Acids.

    Nohr, Daniel; Franz, Sophie; Rodriguez, Ryan; Paulus, Bernd; Essen, Lars-Oliver; Weber, Stefan; Schleicher, Erik

    2016-07-26

    The cryptochrome/photolyase protein family possesses a conserved triad of tryptophans that may act as a molecular wire to transport electrons from the protein surface to the FAD cofactor for activation and/or signaling-state formation. Members from the animal (and animal-like) cryptochrome subclade use this process in a light-induced fashion in a number of exciting responses, such as the (re-)setting of circadian rhythms or magnetoreception; however, electron-transfer pathways have not been explored in detail yet. Therefore, we present an in-depth time-resolved optical and electron-paramagnetic resonance spectroscopic study of two cryptochromes from Chlamydomonas reinhardtii and Drosophila melanogaster. The results do not only reveal the existence of a fourth, more distant aromatic amino acid that serves as a terminal electron donor in both proteins, but also show that a tyrosine is able to fulfill this very role in Chlamydomonas reinhardtii cryptochrome. Additionally, exchange of the respective fourth aromatic amino acid to redox-inactive phenylalanines still leads to light-induced radical pair formation; however, the lifetimes of these species are drastically reduced from the ms- to the μs-range. The results presented in this study open up a new chapter, to our knowledge, in the diversity of electron-transfer pathways in cryptochromes. Moreover, they could explain unique functions of animal cryptochromes, in particular their potential roles in magnetoreception because magnetic-field effects of light-induced radical pairs strongly depend on distance and orientation parameters. PMID:27463133

  13. Ursodeoxycholic Acid Ameliorated Diabetic Nephropathy by Attenuating Hyperglycemia-Mediated Oxidative Stress.

    Cao, Aili; Wang, Li; Chen, Xia; Guo, Hengjiang; Chu, Shuang; Zhang, Xuemei; Peng, Wen

    2016-08-01

    Oxidative stress has a great role in diabetes and diabetes induced organ damage. Endoplasmic reticulum (ER) stress is involved in the onset of diabetic nephropathy. We hypothesize that ER stress inhibition could protect against kidney injury through anti-oxidative effects. To test whether block ER stress could attenuate oxidative stress and improve diabetic nephropathy in vivo and in vitro, the effect of ursodeoxycholic acid (UDCA), an ER stress inhibitor, on spontaneous diabetic nephropathy db/db mice, ER stress inducer or high glucose-triggered podocytes were studied. Mice were assigned to 3 groups (n=6 per group): control group (treated with vehicle), db/db group (treated with vehicle), and UDCA group (db/db mice treated with 40 mg/kg/d UDCA). After 8 weeks treatment, mice were sacrificed. Blood and kidneys were collected for the assessment of albumin/creatinine ratio, blood urea nitrogen (BUN), serum creatinine (SCr), insulin, total cholesterol, triglyceride, low density lipoprotein cholesterol (LDL-C), oxidized LDL-C, high density lipoprotein cholesterol (HDL-C), non-esterified fatty acid (NEFA), superoxide dismutase (SOD), catalase (CAT), methane dicarboxylic aldehyde (MDA), the expressions of SOD isoforms and glutathione peroxidase 1, as well as histopathological examination. In addition, generation of reactive oxygen species (ROS) was detected by 2'7'-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence. The results showed that UDCA alleviated renal ER stress-evoked cell death, oxidative stress, renal dysfunction, ROS production, upregulated the expression of Bcl-2 and suppressed Bax in vivo and in vitro. Hence, inhibition ER stress diminishes oxidative stress and exerts renoprotective effects. PMID:27193377

  14. The antagonistic regulation of abscisic acid-inhibited root growth by brassinosteroids is partially mediated via direct suppression of ABSCISIC ACID INSENSITIVE 5 expression by BRASSINAZOLE RESISTANT 1.

    Yang, Xiaorui; Bai, Yang; Shang, Jianxiu; Xin, Ruijiao; Tang, Wenqiang

    2016-09-01

    Brassinosteroids (BRs) and abscisic acid (ABA) are plant hormones that antagonistically regulate many aspects of plant growth and development; however, the mechanisms that regulate the crosstalk of these two hormones are still not well understood. BRs regulate plant growth and development by activating BRASSINAZOLE RESISTANT 1 (BZR1) family transcription factors. Here we show that the crosstalk between BRs and ABA signalling is partially mediated by BZR1 regulated gene expression. bzr1-1D is a dominant mutant with enhanced BR signalling; our results showed that bzr1-1D mutant is less sensitive to ABA-inhibited primary root growth. By RNA sequencing, a subset of BZR1 regulated ABA-responsive root genes were identified. Of these genes, the expression of a major ABA signalling component ABA INSENSITIVE 5 (ABI5) was found to be suppressed by BR and by BZR1. Additional evidences showed that BZR1 could bind strongly with several G-box cis-elements in the promoter of ABI5, suppress the expression of ABI5 and make plants less sensitive to ABA. Our study demonstrated that ABI5 is a direct target gene of BZR1, and modulating the expression of ABI5 by BZR1 plays important roles in regulating the crosstalk between the BR and ABA signalling pathways. PMID:27149247

  15. Protocatechuic acid induces antioxidant/detoxifying enzyme expression through JNK-mediated Nrf2 activation in murine macrophages.

    Varì, Rosaria; D'Archivio, Massimo; Filesi, Carmelina; Carotenuto, Simona; Scazzocchio, Beatrice; Santangelo, Carmela; Giovannini, Claudio; Masella, Roberta

    2011-05-01

    Protocatechuic acid (PCA) is a main metabolite of anthocyanins, whose daily intake is much higher than that of other polyphenols. PCA has biological effects, e.g., it induces the antioxidant/detoxifying enzyme gene expression. This study was aimed at defining the molecular mechanism responsible for PCA-induced over-expression of glutathione (GSH) peroxidase (GPx) and GSH reductase (GR) in J774 A.1 macrophages. New evidence is provided that PCA increases GPx and GR expression by inducing C-JUN NH(2)-terminal kinase (JNK)-mediated phosphorylation of Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2). RNA and proteins were extracted from cells treated with PCA (25 μM) for different time points. Quantitative real-time polymerase chain reaction and immunoblotting analyses showed a rapid increase in mRNA (>60%) and protein (>50%) for both the enzymes. This was preceded by the up-regulation of Nrf2, in terms of mRNA and protein, and by its significant activation as assessed by increased Nrf2 phosphorylation and nuclear translocation (+60%). By using specific kinase inhibitors and detecting the activated form, we showed that JNK was the main upstream kinase responsible for Nrf2 activation. Convincing evidence is provided of a causal link between PCA-induced Nrf2 activation and increased enzyme expression. By silencing Nrf2 and using a JNK inhibitor, enzyme enhancement was counteracted. Finally, with the ChIP assay, we demonstrated that PCA-activated Nrf2 specifically bound ARE sequences in enzyme gene promoters. Our study demonstrates for the first time that PCA improves the macrophage endogenous antioxidant potential by a mechanism in which JNK-mediated Nrf2 activation plays an essential role. This knowledge could contribute to novel diet-based approaches aimed at counteracting oxidative injury by reinforcing endogenous defences. PMID:20621462

  16. Effect of gamma-aminobutyric acid on neurally mediated contraction of guinea pig trachealis smooth muscle.

    Tamaoki, J; Graf, P D; Nadel, J A

    1987-10-01

    To determine whether gamma-aminobutyric acid (GABA) affects the contractile properties of airway smooth muscle and, if so, what the mechanism of action is, the authors studied guinea pig tracheal rings under isometric conditions in vitro. GABA and related substances, baclofen and muscimol, had no effect on the resting tension but reversibly depressed contractions induced by electrical field stimulation in a dose-dependent fashion, IC50 values (mean +/- S.E.) being 5.6 +/- 1.4 X 10(-6) M, 6.8 +/- 0.9 X 10(-6) M and 8.5 +/- 1.5 X 10(-5) M, respectively. In contrast, GABA did not alter the response to exogenous acetylcholine or the nonadrenergic noncholinergic inhibitory component. Pretreatment of tissues with bicuculline antagonized the inhibitory effect of GABA as well as that of baclofen. This inhibitory effect was not modified by propranolol, phentolamine, hemicholinium-3 or naloxone, but it was blocked by the Cl channel blocker furosemide and by the substitution of external Cl. These results suggest that GABA decreases the contractile response of airway smooth muscle to cholinergic nerve stimulation by inhibiting the evoked release of acetylcholine and that this effect is exerted by activating Cl-dependent, bicuculline-sensitive GABA receptors. PMID:3668869

  17. Activation of the central histaminergic system mediates arachidonic-acid-induced cardiovascular effects.

    Altinbas, Burcin; Topuz, Bora Burak; İlhan, Tuncay; Yilmaz, Mustafa Sertac; Erdost, Hatice; Yalcin, Murat

    2014-08-01

    The aim of this study was to explain the involvement of the central histaminergic system in arachidonic acid (AA)-induced cardiovascular effects in normotensive rats using hemodynamic, immunohistochemistry, and microdialysis studies. Intracerebroventricularly (i.c.v.) administered AA (0.25, 0.5, and 1.0 μmol) induced dose- and time-dependent increases in mean arterial pressure and decreased heart rate in conscious normotensive Sprague-Dawley rats. Central injection of AA (0.5 μmol) also increased posterior hypothalamic extracellular histamine levels and produced strong COX-1 but not COX-2 immunoreactivity in the posterior hypothalamus of rats. Moreover, the cardiovascular effects and COX-1 immunoreactivity in the posterior hypothalamus induced by AA (0.5 μmol; i.c.v.) were almost completely blocked by the H2 receptor antagonist ranitidine (50 and 100 nmol; i.c.v.) and partially blocked by the H1 receptor blocker chlorpheniramine (100 nmol; i.c.v.) and the H3-H4 receptor antagonist thioperamide (50 and 100 nmol; i.c.v.). In conclusion, these results indicate that centrally administered AA induces pressor and bradycardic responses in conscious rats. Moreover, we suggest that AA may activate histaminergic neurons and increase extracellular histamine levels, particularly in the posterior hypothalamus. Acting as a neurotransmitter, histamine is potentially involved in AA-induced cardiovascular effects under normotensive conditions. PMID:25065747

  18. Survival of mycobacteria depends on proteasome-mediated amino acid recycling under nutrient limitation

    Elharar, Yifat; Roth, Ziv; Hermelin, Inna; Moon, Alexandra; Peretz, Gabriella; Shenkerman, Yael; Vishkautzan, Marina; Khalaila, Isam; Gur, Eyal

    2014-01-01

    Intracellular protein degradation is an essential process in all life domains. While in all eukaryotes regulated protein degradation involves ubiquitin tagging and the 26S-proteasome, bacterial prokaryotic ubiquitin-like protein (Pup) tagging and proteasomes are conserved only in species belonging to the phyla Actinobacteria and Nitrospira. In Mycobacterium tuberculosis, the Pup-proteasome system (PPS) is important for virulence, yet its physiological role in non-pathogenic species has remained an enigma. We now report, using Mycobacterium smegmatis as a model organism, that the PPS is essential for survival under starvation. Upon nitrogen limitation, PPS activity is induced, leading to accelerated tagging and degradation of many cytoplasmic proteins. We suggest a model in which the PPS functions to recycle amino acids under nitrogen starvation, thereby enabling the cell to maintain basal metabolic activities. We also find that the PPS auto-regulates its own activity via pupylation and degradation of its components in a manner that promotes the oscillatory expression of PPS components. As such, the destructive activity of the PPS is carefully balanced to maintain cellular functions during starvation. PMID:24986881

  19. Gibberellic acid signaling is required for ambient temperature-mediated induction of flowering in Arabidopsis thaliana.

    Galvão, Vinicius Costa; Collani, Silvio; Horrer, Daniel; Schmid, Markus

    2015-12-01

    Distinct molecular mechanisms integrate changes in ambient temperature into the genetic pathways that govern flowering time in Arabidopsis thaliana. Temperature-dependent eviction of the histone variant H2A.Z from nucleosomes has been suggested to facilitate the expression of FT by PIF4 at elevated ambient temperatures. Here we show that, in addition to PIF4, PIF3 and PIF5, but not PIF1 and PIF6, can promote flowering when expressed specifically in phloem companion cells (PCC), where they can induce FT and its close paralog, TSF. However, despite their strong potential to promote flowering, genetic analyses suggest that the PIF genes seem to have only a minor role in adjusting flowering in response to photoperiod or high ambient temperature. In addition, loss of PIF function only partially suppressed the early flowering phenotype and FT expression of the arp6 mutant, which is defective in H2A.Z deposition. In contrast, the chemical inhibition of gibberellic acid (GA) biosynthesis resulted in a strong attenuation of early flowering and FT expression in arp6. Furthermore, GA was able to induce flowering at low temperature (15°C) independently of FT, TSF, and the PIF genes, probably directly at the shoot apical meristem. Together, our results suggest that the timing of the floral transition in response to ambient temperature is more complex than previously thought and that GA signaling might play a crucial role in this process. PMID:26466761

  20. Sustained Release and Cytotoxicity Evaluation of Carbon Nanotube-Mediated Drug Delivery System for Betulinic Acid

    Julia M. Tan

    2014-01-01

    Full Text Available Carbon nanotubes (CNTs have been widely utilized as a novel drug carrier with promising future applications in biomedical therapies due to their distinct characteristics. In the present work, carboxylic acid-functionalized single-walled carbon nanotubes (f-SWCNTs were used as the starting material to react with anticancer drug, BA to produce f-SWCNTs-BA conjugate via π-π stacking interaction. The conjugate was extensively characterized for drug loading capacity, physicochemical properties, surface morphology, drug releasing characteristics, and cytotoxicity evaluation. The results indicated that the drug loading capacity was determined to be around 20 wt% and this value has been verified by thermogravimetric analysis. The binding of BA onto the surface of f-SWCNTs was confirmed by FTIR and Raman spectroscopies. Powder XRD analysis showed that the structure of the conjugate was unaffected by the loading of BA. The developed conjugate was found to release the drug in a controlled manner with a prolonged release property. According to the preliminary in vitro cytotoxicity studies, the conjugate was not toxic in a standard fibroblast cell line, and anticancer activity was significantly higher in A549 than HepG2 cell line. This study suggests that f-SWCNTs could be developed as an efficient drug carrier to conjugate drugs for pharmaceutical applications in cancer chemotherapies.

  1. Salvianolic acid B protects endothelial cells from oxidant-mediated damage

    LI Xue-jun

    2008-01-01

    Objective To investigate the protective effects of Salvianolic acid B(Sal B) on hydrogen peroxide (H2O2)-induced injury in human umbilical vein endothelial cells (HUVECs). Sal B is considered as one of the most active anti-oxidant and the major pharmacological component of the herb, Salvia miltiorrhiza. Its beneficial effects include hepatoprotection, elicitation of endothelium-dependent vasodilation, lowering blood pressure in hypertension, inhibition of HIV-1 replication and suppressing inflammatory cytokine- stimulated endothelial adhesiveness to human monocytie cells by its strong antioxidant activities. Methods Treatment with H2O2 significantly decreased the cell viability and increased the lactate dehydrogenase (LDH) leakage that is an apoptotic feature. Pretreatment with Sal B prevented significantly from H2O2-induced cell apoptosis and other damages in a concentration-dependent manner. The mechanism of Sal B protection was studied with two-dimensional gel electrophoresis (2-DE) coupled to hybrid quadrupole time-of-flight mass spectrometry (Q-TOF) mass spectrometer. Results Data base searching implicated glucose-regulated protein 78 (GRP78), a central regulator for ER stress, was up-regulated in Sal B-exposed HUVECs. After exposure to Sal B, the level of activating transcription factor 4 (ATF4) was raised, with a transient phosphorylation of the α subunit of eukaryotic translation initiation factor (eIF2α). Knock-down of GRP78 by siRNA significantly reduced protective effects of Sal B. Conclusions These results suggest that Sal B-induced GRP78 upregulation via phosphorylation of eIF2α and resultant translation of ATF4. And up-regulation of ER chaperones induced by Sal B may play an important role in protecting human endothelial cells from oxidative stress-induced cellular damage.

  2. Laccase mediated-synthesis of hydroxycinnamoyl-peptide from ferulic acid and carnosine.

    Aljawish, Abdulhadi; Chevalot, Isabelle; Madad, Nidal; Paris, Cédric; Muniglia, Lionel

    2016-06-10

    Carnosine (CAR) dipeptide was functionalized with ferulic acid (FA) as substrate using laccase from Myceliophtora thermophila as biocatalyst. The enzymatic reaction was performed in aqueous medium under mild conditions (pH 7.5, 30°C) as an eco-friendly procedure. Results showed that this enzymatic process led to the synthesis of two new derivatives (P1, P2), from the coupling between CAR and FA derived products. Conditions allowing a high production of P1, P2 derivatives were determined with an optimal ratio of (FA: CAR) of (1:1.6) at optimal time reaction of 8h. Under these optimal conditions, the coupling between CAR and FA-products was demonstrated, resulting in the decrease of -NH2 groups (almost 50%) as quantified via derivatization. Due to the presence of FA in the structure of these new derivatives, they exhibited higher hydrophobic property than carnosine. Structural analyses by mass spectrometry showed that P1 and P2 (FA-CAR) derivatives exhibited the same molecular mass (MM 770g/mol) containing one CAR-molecule and three FA-molecules but with different chemical structures. Furthermore, these derivatives presented improved antioxidant (almost 10 times) and anti-proliferative (almost 18 times) properties in comparison with CAR. Moreover, P1 derivative exhibited higher antioxidant and anti-proliferative activities than P2 derivative, which confirmed the different structures of P1 and P2. These results suggested that the oxidized phenols coupling with carnosine is a promising process to enhance the CAR-properties. PMID:27084055

  3. p-Aminophenylacetic acid-mediated synthesis of monodispersed titanium oxide hybrid microspheres in ethanol solution.

    Zhang, Hongye; Xie, Yun; Liu, Zhimin; Tao, Ranting; Sun, Zhenyu; Ding, Kunlun; An, Guimin

    2009-10-15

    Monodispersed TiO2 hybrid microspheres were prepared via the hydrolysis of titanium isopropoxide (TTIP) in ethanol solution containing p-aminophenylacetic acid (APA). The effects of the APA:TTIP molar ratio, water content, reaction time and reaction temperature on the morphology of the resultant spheres were investigated. The products were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. It was demonstrated that the diameters of the resultant TiO2 spheres could be tuned in the range of 380-800 nm by changing the APA:TTIP molar ratio (1:3 to 3:1) and water content (1-3 v/v%) in the reaction medium, and that increasing the APA:TTIP molar ratio led to larger TiO2 hybrid spheres while increasing the water content decreased their size. The loading content of APA in the hybrid spheres could reach 20 wt.% as they were prepared with the APA:TTIP ratio of 3:1. The possible formation mechanism of the hybrid spheres was also investigated. It was found that APA slowed down the hydrolysis rate of the titanium precursor so that resulted in the formation of the TiO2 spheres. In addition, the APA present in TiO2 spheres acted as a reducing agent to in situ convert HAuCl4 into metallic Au on the surface of the TiO2 spheres. The catalytic activity of the resultant Au/APA-TiO2 composite was examined using transfer hydrogenation of phenylacetone with 2-propanol, and it was indicated that the catalyst displayed high efficiency for this reaction. PMID:19616218

  4. Generation of reactive oxygen species by a novel berberine–bile acid analog mediates apoptosis in hepatocarcinoma SMMC-7721 cells

    Li, Qingyong, E-mail: li_qingyong@126.com [Key Laboratory of Forest Plant Ecology (Northeast Forestry University), Ministry of Education (China); Zhang, Li; Zu, Yuangang; Liu, Tianyu; Zhang, Baoyou; He, Wuna [Key Laboratory of Forest Plant Ecology (Northeast Forestry University), Ministry of Education (China)

    2013-04-19

    Graphical abstract: - Highlights: • Anticancer effects of B4, a novel berberine–bile acid analog, were tested. • B4 inhibited cell proliferation in hepatocellular carcinoma cells. • It also stimulated mitochondrial ROS production and membrane depolarization. • Effects of B4 were inhibited by a non-specific ROS scavenger. • Regulation of ROS generation may be a strategy for treating hepatic carcinoma. - Abstract: 2,3-Methenedioxy-9-O-(3′α,7′α-dihydroxy-5′β-cholan-24′-propy-lester) berberine (B4) is a novel berberine–bile acid analog synthesized in our laboratory. Previously, we showed that B4 exerted greater cytotoxicity than berberine in several human cancer cell lines. Therefore, we further evaluated the mechanism governing its anticancer actions in hepatocellular carcinoma SMMC-7721 cells. B4 inhibited the proliferation of SMMC-7721 cells, and stimulated reactive oxygen species (ROS) production and mitochondrial membrane depolarization; anti-oxidant capacity was reduced. B4 also induced the release of cytochrome c from the mitochondria to the cytosol and an increase in poly ADP-ribose polymerase (PARP) cleavage products, reflective of caspase-3 activation. Moreover, B4 induced the nuclear translocation of apoptosis-inducing factor (AIF) and a rise in DNA fragmentation. Pretreatment with the anti-oxidant N-acetylcysteine (NAC) inhibited B4-mediated effects, including cytotoxicity, ROS production, mitochondrial membrane depolarization increase in intracellular Ca{sup 2+}, cytochrome c release, PARP cleavage, and AIF translocation. Our data suggest that B4 induces ROS-triggered caspase-dependent and caspase-independent apoptosis pathways in SMMC-7721 cells and that ROS production may be a specific potential strategy for treating hepatic carcinoma.

  5. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  6. Generation of reactive oxygen species by a novel berberine–bile acid analog mediates apoptosis in hepatocarcinoma SMMC-7721 cells

    Graphical abstract: - Highlights: • Anticancer effects of B4, a novel berberine–bile acid analog, were tested. • B4 inhibited cell proliferation in hepatocellular carcinoma cells. • It also stimulated mitochondrial ROS production and membrane depolarization. • Effects of B4 were inhibited by a non-specific ROS scavenger. • Regulation of ROS generation may be a strategy for treating hepatic carcinoma. - Abstract: 2,3-Methenedioxy-9-O-(3′α,7′α-dihydroxy-5′β-cholan-24′-propy-lester) berberine (B4) is a novel berberine–bile acid analog synthesized in our laboratory. Previously, we showed that B4 exerted greater cytotoxicity than berberine in several human cancer cell lines. Therefore, we further evaluated the mechanism governing its anticancer actions in hepatocellular carcinoma SMMC-7721 cells. B4 inhibited the proliferation of SMMC-7721 cells, and stimulated reactive oxygen species (ROS) production and mitochondrial membrane depolarization; anti-oxidant capacity was reduced. B4 also induced the release of cytochrome c from the mitochondria to the cytosol and an increase in poly ADP-ribose polymerase (PARP) cleavage products, reflective of caspase-3 activation. Moreover, B4 induced the nuclear translocation of apoptosis-inducing factor (AIF) and a rise in DNA fragmentation. Pretreatment with the anti-oxidant N-acetylcysteine (NAC) inhibited B4-mediated effects, including cytotoxicity, ROS production, mitochondrial membrane depolarization increase in intracellular Ca2+, cytochrome c release, PARP cleavage, and AIF translocation. Our data suggest that B4 induces ROS-triggered caspase-dependent and caspase-independent apoptosis pathways in SMMC-7721 cells and that ROS production may be a specific potential strategy for treating hepatic carcinoma

  7. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    Song, Jun [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Ren, Pingping; Zhang, Lin [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Wang, Xing Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Chen, Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Shen, Ying H., E-mail: hyshen@bcm.edu [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States)

    2010-02-26

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  8. Salicylic acid is required for Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci, but not for basal defense to this insect pest.

    Rodríguez-Álvarez, C I; López-Climent, M F; Gómez-Cadenas, A; Kaloshian, I; Nombela, G

    2015-10-01

    Plant defense to pests or pathogens involves global changes in gene expression mediated by multiple signaling pathways. A role for the salicylic acid (SA) signaling pathway in Mi-1-mediated resistance of tomato (Solanum lycopersicum) to aphids was previously identified and its implication in the resistance to root-knot nematodes is controversial, but the importance of SA in basal and Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci had not been determined. SA levels were measured before and after B. tabaci infestation in susceptible and resistant Mi-1-containing tomatoes, and in plants with the NahG bacterial transgene. Tomato plants of the same genotypes were also screened with B. tabaci (MEAM1 and MED species, before known as B and Q biotypes, respectively). The SA content in all tomato genotypes transiently increased after infestation with B. tabaci albeit at variable levels. Whitefly fecundity or infestation rates on susceptible Moneymaker were not significantly affected by the expression of NahG gene, but the Mi-1-mediated resistance to B. tabaci was lost in VFN NahG plants. Results indicated that whiteflies induce both SA and jasmonic acid accumulation in tomato. However, SA has no role in basal defense of tomato against B. tabaci. In contrast, SA is an important component of the Mi-1-mediated resistance to B. tabaci in tomato. PMID:26032615

  9. Induction of G2/M arrest by pseudolaric acid B is mediated by activation of the ATM signaling pathway

    Ai-guo MENG; Ling-lingJIANG

    2009-01-01

    Aim: The aim of this study was to investigate the mechanism of pseudolaric acid B (PLAB)-induced cell cycle arrest in human melanoma SK-28 cells. Methods: Cell growth inhibition was detected by MTT assay, the cell cycle was analyzed by flow cytometry, and protein expression was examined by Western blot analysis.Results: PLAB inhibited the growth of human melanoma ceils and induced G2/M arrest in SK-28 cells, accompanied by an up-regulation of Cdc2 phosphorylation and a subsequent down-regulation of Cdc2 expression. Furthermore, PLAB decreased the expression of Cdc25C phosphatase and increased the expression of Wee1 kinase. Meanwhile, a reduction in Cdc2 activity was party due to induction of the expression of p21wsaf1/cip1 in a p53-dependent manner. In addition, PLAB activated the checkpoint kinase, Chk2, and increased the expression of p53, two major targets of ATM kinase. These effects were inhibited by caffeine, an ATM kinase inhibitor. We also found that PLAB significantly enhanced ATM kinase activity. Conclusion: Taken together, these results suggest that PLAB induced G2/M arrest in human melanoma cells via a mechanism involving the activation of ATM, and the effect of PLAB on Cdc2 activity was mediated via interactions with the Chk2-Cdc25C and p53 signalling pathways, two distinct downstream pathways of ATM. PLAB may be a promising chemopreventive agent for treating human melanoma.

  10. Suppression of Jasmonic Acid-Mediated Defense by Viral-Inducible MicroRNA319 Facilitates Virus Infection in Rice.

    Zhang, Chao; Ding, Zuomei; Wu, Kangcheng; Yang, Liang; Li, Yang; Yang, Zhen; Shi, Shan; Liu, Xiaojuan; Zhao, Shanshan; Yang, Zhirui; Wang, Yu; Zheng, Luping; Wei, Juan; Du, Zhenguo; Zhang, Aihong; Miao, Hongqin; Li, Yi; Wu, Zujian; Wu, Jianguo

    2016-09-01

    MicroRNAs (miRNAs) are pivotal modulators of plant development and host-virus interactions. However, the roles and action modes of specific miRNAs involved in viral infection and host susceptibility remain largely unclear. In this study, we show that Rice ragged stunt virus (RRSV) infection caused increased accumulation of miR319 but decreased expression of miR319-regulated TCP (TEOSINTE BRANCHED/CYCLOIDEA/PCF) genes, especially TCP21, in rice plants. Transgenic rice plants overexpressing miR319 or downregulating TCP21 exhibited disease-like phenotypes and showed significantly higher susceptibility to RRSV in comparison with the wild-type plants. In contrast, only mild disease symptoms were observed in RRSV-infected lines overexpressing TCP21 and especially in the transgenic plants overexpressing miR319-resistant TCP21. Both RRSV infection and overexpression of miR319 caused the decreased endogenous jasmonic acid (JA) levels along with downregulated expression of JA biosynthesis and signaling-related genes in rice. However, treatment of rice plants with methyl jasmonate alleviated disease symptoms caused by RRSV and reduced virus accumulation. Taken together, our results suggest that the induction of miR319 by RRSV infection in rice suppresses JA-mediated defense to facilitate virus infection and symptom development. PMID:27381440

  11. Fe{sub 3}O{sub 4}/salicylic acid nanoparticles versatility in magnetic mediated vascular nanoblockage

    Mîndrilă, I., E-mail: tutu0101@yahoo.com [University of Medicine and Pharmacy of Craiova, Faculty of Medicine (Romania); Buteică, S. A. [University of Medicine and Pharmacy of Craiova, Faculty of Pharmacy (Romania); Mihaiescu, D. E.; Badea, G.; Fudulu, A. [Politehnica University of Bucharest, Faculty of Applied Chemistry and Material Science (Romania); Mărgăritescu, D. N. [University of Medicine and Pharmacy of Craiova, Faculty of Medicine (Romania)

    2016-01-15

    An aqueous dispersion of Fe{sub 3}O{sub 4}/salicylic acid magnetic nanoparticles (SaMNPs) was synthesized by a modified Massart method, characterized by Inductively Coupled Plasma–Optic Emission Spectrometry (ICP-OES), High-Resolution Transmission Electron Microscopy (HRTEM) and Dynamic Light Scattering (DLS) methods, and tested on the chick chorioallantoic membrane (CAM) model to evaluate biocompatibility, biodistribution, intravascular time persistence, and ability to be magnetically target driven in order to block the blood supply into a tumor xenograft. ICP-OES, DLS, and HRTEM SaMNPs sample analyses showed a 0.356 mg/mL Fe concentration, a good stability in water (average Zeta potential of 39.3 mV), a hydrodynamic diameter around 52 nm and a core diameter in the 7–15 nm range for the Fe{sub 3}O{sub 4} nanoparticles. In vivo CAM assay showed that SaMNPs were biocompatible with the chick embryo, were fixed almost completely by the liver, had no embolic potential, and a threshold-dose-dependent intravascular magnetic targeting time. Study on the CAM tumor model showed that SaMNPs could be used for long-term magnetically mediated nanoblocking of the capillary networks and 70-µm smaller arterioles.

  12. Matrix metalloproteinase-13 mediated degradation of hyaluronic acid-based matrices orchestrates stem cell engraftment through vascular integration.

    Jha, Amit K; Tharp, Kevin M; Browne, Shane; Ye, Jianqin; Stahl, Andreas; Yeghiazarians, Yerem; Healy, Kevin E

    2016-05-01

    A critical design parameter for the function of synthetic extracellular matrices is to synchronize the gradual cell-mediated degradation of the matrix with the endogenous secretion of natural extracellular matrix (ECM) (e.g., creeping substitution). In hyaluronic acid (HyA)-based hydrogel matrices, we have investigated the effects of peptide crosslinkers with different matrix metalloproteinases (MMP) sensitivities on network degradation and neovascularization in vivo. The HyA hydrogel matrices consisted of cell adhesive peptides, heparin for both the presentation of exogenous and sequestration of endogenously synthesized growth factors, and MMP cleavable peptide linkages (i.e., QPQGLAK, GPLGMHGK, and GPLGLSLGK). Sca1(+)/CD45(-)/CD34(+)/CD44(+) cardiac progenitor cells (CPCs) cultured in the matrices with the slowly degradable QPQGLAK hydrogels supported the highest production of MMP-2, MMP-9, MMP-13, VEGF165, and a range of angiogenesis related proteins. Hydrogels with QPQGLAK crosslinks supported prolonged retention of these proteins via heparin within the matrix, stimulating rapid vascular development, and anastomosis with the host vasculature when implanted in the murine hindlimb. PMID:26967648

  13. Valproic acid reduces insulin-resistance, fat deposition and FOXO1-mediated gluconeogenesis in type-2 diabetic rat.

    Khan, Sabbir; Kumar, Sandeep; Jena, Gopabandhu

    2016-06-01

    Recent evidences highlighted the role of histone deacetylases (HDACs) in insulin-resistance, gluconeogenesis and islet function. HDACs can modulate the expression of various genes, which directly or indirectly affect glucose metabolism. This study was aimed to evaluate the role of valproic acid (VPA) on fat deposition, insulin-resistance and gluconeogenesis in type-2 diabetic rat. Diabetes was developed in Sprague-Dawley rats by the combination of high-fat diet and low dose streptozotocin. VPA at the doses of 150 and 300 mg/kg/day and metformin (positive control) 150 mg/kg twice daily for 10 weeks were administered by oral gavage. Insulin-resistance, dyslipidemia and glycemia were evaluated by biochemical estimations, while fat accumulation and structural alteration were assessed by histopathology. Protein expression and insulin signaling were evaluated by western blot and immunohistochemistry. VPA treatment significantly reduced the plasma glucose, HbA1c, insulin-resistance, fat deposition in brown adipose tissue, white adipose tissue and liver, which are comparable to metformin treatment. Further, VPA inhibited the gluconeogenesis and glucagon expression as well as restored the histopathological alterations in pancreas and liver. Our findings provide new insights on the anti-diabetic role of VPA in type-2 diabetes mellitus by the modulation of insulin signaling and forkhead box protein O1 (FOXO1)-mediated gluconeogenesis. Since VPA is a well established clinical drug, the detailed molecular mechanisms of the present findings can be further investigated for possible clinical use. PMID:26944797

  14. Epoxycarotenoid-mediated synthesis of abscisic acid in Physcomitrella patens implicating conserved mechanisms for acclimation to hyperosmosis in embryophytes.

    Takezawa, Daisuke; Watanabe, Naoki; Ghosh, Totan Kumar; Saruhashi, Masashi; Suzuki, Atsushi; Ishiyama, Kanako; Somemiya, Shinnosuke; Kobayashi, Masatomo; Sakata, Yoichi

    2015-04-01

    Plants acclimate to environmental stress signals such as cold, drought and hypersalinity, and provoke internal protective mechanisms. Abscisic acid (ABA), a carotenoid-derived phytohormone, which increases in response to the stress signals above, has been suggested to play a key role in the acclimation process in angiosperms, but the role of ABA in basal land plants such as mosses, including its biosynthetic pathways, has not been clarified. Targeted gene disruption of PpABA1, encoding zeaxanthin epoxidase in the moss Physcomitrella patens was conducted to determine the role of endogenous ABA in acclimation processes in mosses. The generated ppaba1 plants were found to accumulate only a small amount of endogenous ABA. The ppaba1 plants showed reduced osmotic acclimation capacity in correlation with reduced dehydration tolerance and accumulation of late embryogenesis abundant proteins. By contrast, cold-induced freezing tolerance was less affected in ppaba1, indicating that endogenous ABA does not play a major role in the regulation of cold acclimation in the moss. Our results suggest that the mechanisms for osmotic acclimation mediated by carotenoid-derived synthesis of ABA are conserved in embryophytes and that acquisition of the mechanisms played a crucial role in terrestrial adaptation and colonization by land plant ancestors. PMID:25545104

  15. Physical size of the donor locus and transmission of Haemophilus influenzae ampicillin resistance genes by deoxyribonucleic acid-mediated transformation

    The properties of donor deoxyribonucleic acid (DNA) from three clinical isolates and its ability to mediate the transformation of competent Rd strains to ampicillin resistance were examined. A quantitative technique for determining the resistance of individual Haemophilus influenzae cells to ampicillin was developed. When this technique was used, sensitive cells failed to tolerate levels of ampicillin greater than 0.1 to 0.2 μg/ml, whereas three resistant type b β-lactamase-producing strains could form colonies 1- to 3-μg/ml levels of the antibiotic. DNA extracted from the resistant strains elicited transformation of the auxotrophic genes in a multiply auxotrophic Rd strain. For two of the donors, transformation to ampicillin resistance occurred after the uptake of a single DNA molecule approximately 104-fold less frequently than transformation of auxotrophic loci and was not observed to occur at all with the third. The frequency of transformation to ampicillin resistance was two- to fivefold higher in strain BC200 (Okinaka and Barnhart, 1974), which was cured of a defective prophage. All three clinical ampicillin-resistant strains were poor recipients, but the presence of the ampicillin resistant genes in strain BC200 did not reduce its competence

  16. Biological activity of all-trans retinol requires metabolic conversion to all-trans retinoic acid and is mediated through activation of nuclear retinoid receptors in human keratinocytes.

    Kurlandsky, S B; Xiao, J H; Duell, E A; Voorhees, J J; Fisher, G J

    1994-12-30

    The biological activity of all-trans retinol, in human keratinocytes, was investigated through metabolic and functional analyses that assessed the capacity for retinol uptake and metabolism and the mechanism of retinol-induced activation of gene transcription. Human keratinocytes converted all-trans retinol predominantly to retinyl esters, which accounted for 60 and 90% of cell-associated radiolabel after a 90-min pulse and a 48-h chase, respectively. Human keratinocytes also metabolized all-trans retinol to low levels of all-trans retinoic acid (11.47-131.3 ng/mg of protein) in a dose-dependent manner, between 0.3 and 10 microM added retinol. Small amounts of 13-cis retinoic acid (5.47-8.62 ng/mg of protein) were detected, but 9-cis retinoic acid was detected only when keratinocytes were incubated with radiolabeled retinol. There was no accumulation of the oxidized catabolic metabolites 4-hydroxy- or 4-oxoretinoic acid; however, 5,6-epoxy retinoic acid was detected at pharmacological levels (10 and 30 microM) of added retinol. Biological activity of retinol was assessed through analysis of two known retinoic acid-mediated responses: 1) reduction of type I epidermal transglutaminase and 2) activation of a retinoic acid receptor-dependent reporter gene, beta RARE3-tk-CAT. Both all-trans retinol and all-trans retinoic acid reduced type I epidermal transglutaminase in a dose-dependent manner; however, the ED50 for all-trans retinol (10 nM) was 10 times greater than for all-trans retinoic acid (1 nM). All-trans retinol also stimulated beta RARE3-tk-CAT reporter gene activity in a dose-dependent manner. Half-maximal induction was observed at 30 nM retinol, which was again 10-fold greater than observed with all-trans retinoic acid. Cotransfection of human keratinocytes with expression vectors for dominant negative mutant retinoic acid and retinoid X receptors reduced retinol-induced beta RARE3-tk-CAT reporter gene activation by 80%. Inhibition of conversion of all

  17. Suppression of Salicylic Acid-Mediated Plant Defense Responses During Initial Infection of Dyer's Woad by Puccinia thlaspeos

    Elizabeth Thomas

    2011-01-01

    Full Text Available Problem statement: Puccinia thlaspeos is a microcyclic rust pathogen that is being investigated as a potential biocontrol agent of the noxious weed, dyer’s woad (Isatis tinctoria. Although, the initial events in the colonization of dyer’s woad by the rust pathogen has been elucidated using scanning electron microscopy and PCR, little is known regarding the susceptibility response of this plant to its rust pathogen. Approach: The induction kinetics and amplitude of the Salicylic Acid (SA-responsive Pathogenesis-Related (PR genes, PR-1, â-1, 3-glucanase and ChiA in the compatible interaction between the rust pathogen Puccinia thlaspeos and dyer’s woad were examined during the first 72 h of the infection process. Furthermore SA, an inducer of plant defense response was applied to infected plants in order to reprogram the host defense response at periods that coincided with key events of the infection process. Results: PR genes were upregulated following host penetration by the pathogen. A subsequent pathogen-mediated suppression of PR genes was seen that corresponded with haustorium formation. This was followed by a second up-regulation of these genes that was, in turn, followed by a second long-term pathogen-induced suppression of the defense response that appears to allow successful infections in dyer’s woad. Exogenous application of SA to uninoculated plants led to activation of defense responses by 8 h after treatment. In treatments where inoculated plants were treated with SA, responses differed depending on the timing of SA application. Application of SA at times corresponding to the pre-haustorial and posthaustorial phases of infection triggered an up-regulation of defense genes and increased protection against the pathogen. However, the application of SA during haustorium formation could not override the pathogen-mediated suppression of defense responses and consequently, did not offer the host increased protection. Conclusion

  18. Autotaxin, a synthetic enzyme of lysophosphatidic acid (LPA, mediates the induction of nerve-injured neuropathic pain

    Chun Jerold

    2008-02-01

    Full Text Available Abstract Recently, we reported that lysophosphatidic acid (LPA induces long-lasting mechanical allodynia and thermal hyperalgesia as well as demyelination and upregulation of pain-related proteins through one of its cognate receptors, LPA1. In addition, mice lacking the LPA1 receptor gene (lpa1-/- mice lost these nerve injury-induced neuropathic pain behaviors and phenomena. However, since lpa1-/- mice did not exhibit any effects on the basal nociceptive threshold, it is possible that nerve injury-induced neuropathic pain and its machineries are initiated by LPA via defined biosynthetic pathways that involve multiple enzymes. Here, we attempted to clarify the involvement of a single synthetic enzyme of LPA known as autotaxin (ATX in nerve injury-induced neuropathic pain. Wild-type mice with partial sciatic nerve injury showed robust mechanical allodynia starting from day 3 after the nerve injury and persisting for at least 14 days, along with thermal hyperalgesia. On the other hand, heterozygous mutant mice for the autotaxin gene (atx+/-, which have 50% ATX protein and 50% lysophospholipase D activity compared with wild-type mice, showed approximately 50% recovery of nerve injury-induced neuropathic pain. In addition, hypersensitization of myelinated Aβ˜ MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGacaGaaiaabeqaaeqabiWaaaGcbaGafqOSdiMbaGaaaaa@2D83@- or Aδ-fiber function following nerve injury was observed in electrical stimuli-induced paw withdrawal tests using a Neurometer®. The hyperalgesia was completely abolished in lpa1-/- mice, and reduced by 50% in atx+/- mice. Taken together, these findings suggest that LPA biosynthesis through ATX is the source of LPA for LPA1 receptor-mediated neuropathic pain. Therefore, targeted inhibition of ATX-mediated LPA biosynthesis as well as

  19. L-Lactate-mediated Dynamic Kinetic Resolution of α-Bromo Esters for Asymmetric Syntheses of α-Amino Acid Derivatives

    We conclude that ethyl L-lactate is an effective and convenient chiral auxiliary for dynamic kinetic resolution of α-bromo esters in nucleophilic substitution with various amine nucleophiles. The methodology can provide a general procedure for asymmetric syntheses of dihydroquinoxalinones, dihydrobenzoxazinones and 1,1'-iminodicarboxylic acid derivatives. Simple and easy procedure in obtaining highly enantioenriched α-amino acid derivatives suggests that the dynamic kinetic resolution approach should be further developed. For asymmetric synthesis of α-substituted carboxylic acid derivatives, a variety of chiral auxiliaries have been used for the dynamic resolution of α-halo esters in nucleophilic substitution.1 For example, L-lactamide-mediated dynamic kinetic resolution of α-bromo esters was successfully used for the asymmetric preparation of α-aryloxy carboxylic acids and oxazin-2-ones

  20. L-Lactate-mediated Dynamic Kinetic Resolution of α-Bromo Esters for Asymmetric Syntheses of α-Amino Acid Derivatives

    Kim, Yelim; Park, Kon Ji; Choi, Yun Soo; Lee, Myungsu; Park, Yong Sun [Konkuk Univ., Seoul (Korea, Republic of)

    2013-08-15

    We conclude that ethyl L-lactate is an effective and convenient chiral auxiliary for dynamic kinetic resolution of α-bromo esters in nucleophilic substitution with various amine nucleophiles. The methodology can provide a general procedure for asymmetric syntheses of dihydroquinoxalinones, dihydrobenzoxazinones and 1,1'-iminodicarboxylic acid derivatives. Simple and easy procedure in obtaining highly enantioenriched α-amino acid derivatives suggests that the dynamic kinetic resolution approach should be further developed. For asymmetric synthesis of α-substituted carboxylic acid derivatives, a variety of chiral auxiliaries have been used for the dynamic resolution of α-halo esters in nucleophilic substitution.1 For example, L-lactamide-mediated dynamic kinetic resolution of α-bromo esters was successfully used for the asymmetric preparation of α-aryloxy carboxylic acids and oxazin-2-ones.

  1. Siderocalin/Lcn2/NGAL/24p3 does not drive apoptosis through gentisic acid mediated iron withdrawal in hematopoietic cell lines.

    Colin Correnti

    Full Text Available Siderocalin (also lipocalin 2, NGAL or 24p3 binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that siderocalin does not induce cellular iron efflux or stimulate apoptosis, questioning the role siderocalin plays in modulating iron metabolism.

  2. Mouse Siglec-1 Mediates trans-Infection of Surface-bound Murine Leukemia Virus in a Sialic Acid N-Acyl Side Chain-dependent Manner.

    Erikson, Elina; Wratil, Paul R; Frank, Martin; Ambiel, Ina; Pahnke, Katharina; Pino, Maria; Azadi, Parastoo; Izquierdo-Useros, Nuria; Martinez-Picado, Javier; Meier, Chris; Schnaar, Ronald L; Crocker, Paul R; Reutter, Werner; Keppler, Oliver T

    2015-11-01

    Siglec-1 (sialoadhesin, CD169) is a surface receptor on human cells that mediates trans-enhancement of HIV-1 infection through recognition of sialic acid moieties in virus membrane gangliosides. Here, we demonstrate that mouse Siglec-1, expressed on the surface of primary macrophages in an interferon-α-responsive manner, captures murine leukemia virus (MLV) particles and mediates their transfer to proliferating lymphocytes. The MLV infection of primary B-cells was markedly more efficient than that of primary T-cells. The major structural protein of MLV particles, Gag, frequently co-localized with Siglec-1, and trans-infection, primarily of surface-bound MLV particles, efficiently occurred. To explore the role of sialic acid for MLV trans-infection at a submolecular level, we analyzed the potential of six sialic acid precursor analogs to modulate the sialylated ganglioside-dependent interaction of MLV particles with Siglec-1. Biosynthetically engineered sialic acids were detected in both the glycolipid and glycoprotein fractions of MLV producer cells. MLV released from cells carrying N-acyl-modified sialic acids displayed strikingly different capacities for Siglec-1-mediated capture and trans-infection; N-butanoyl, N-isobutanoyl, N-glycolyl, or N-pentanoyl side chain modifications resulted in up to 92 and 80% reduction of virus particle capture and trans-infection, respectively, whereas N-propanoyl or N-cyclopropylcarbamyl side chains had no effect. In agreement with these functional analyses, molecular modeling indicated reduced binding affinities for non-functional N-acyl modifications. Thus, Siglec-1 is a key receptor for macrophage/lymphocyte trans-infection of surface-bound virions, and the N-acyl side chain of sialic acid is a critical determinant for the Siglec-1/MLV interaction. PMID:26370074

  3. Site-Specific Enhancement of γ-Aminobutyric Acid-Mediated Inhibition of Neural Activity by Ethanol in the Rat Medial Septal Area1

    GIVENS, BENNET S.; Breese, George R.

    1990-01-01

    Because of uncertainty concerning the interaction of ethanol with γ-aminobutyric acid (GABA) receptor-mediated events, the present work was designed to investigate the effect of ethanol on GABA transmission in the rat septal area using behavioral and electrophysiological techniques. Microinjection of the GABAA agonist muscimol into the medial septal area (MSA) enhanced, and bicuculline administration antagonized, ethanol-induced impairment of the aerial righting reflex. Microinjection of thes...

  4. The Protective Effect of Alpha-Lipoic Acid in Lipopolysaccharide-Induced Acute Lung Injury Is Mediated by Heme Oxygenase-1

    Yu-Chieh Lin; Yuan-Shu Lai; Tz-Chong Chou

    2013-01-01

    Alpha-lipoic acid (ALA), occurring naturally in human food, is known to possess antioxidative and anti-inflammatory activities. Induction of heme oxygenase-1 (HO-1) has been reported to exhibit a therapeutic effect in several inflammatory diseases. The aim of study was to test the hypothesis that the protection of ALA against lipopolysaccharide-(LPS-) induced acute lung injury (ALI) is mediated by HO-1. Pre- or posttreatment with ALA significantly inhibited LPS-induced histological alteration...

  5. Bile acids-mediated overexpression of MUC4 via FAK-dependent c-Jun activation in pancreatic cancer.

    Joshi, Suhasini; Cruz, Eric; Rachagani, Satyanarayana; Guha, Sushovan; Brand, Randall E; Ponnusamy, Moorthy P; Kumar, Sushil; Batra, Surinder K

    2016-08-01

    The majority of pancreatic cancer (PC) patients are clinically presented with obstructive jaundice with elevated levels of circulatory bilirubin and alkaline phosphatases. In the current study, we examined the implications of bile acids (BA), an important component of bile, on the pathophysiology of PC and investigated their mechanistic association in tumor-promoting functions. Integration of results from PC patient samples and autochthonous mouse models showed an elevated levels of BA (p < 0.05) in serum samples compared to healthy controls. Similarly, an elevated BA levels was observed in pancreatic juice derived from PC patients (p < 0.05) than non-pancreatic non-healthy (NPNH) controls, further establishing the clinical association of BA with the pathogenesis of PC. The tumor-promoting functions of BA were established by observed transcriptional upregulation of oncogenic MUC4 expression. Luciferase reporter assay revealed distal MUC4 promoter as the primary responsive site to BA. In silico analysis recognized two c-Jun binding sites at MUC4 distal promoter, which was biochemically established using ChIP assay. Interestingly, BA treatment led to an increased transcription and activation of c-Jun in a FAK-dependent manner. Additionally, BA receptor, namely FXR, which is also upregulated at transcriptional level in PC patient samples, was demonstrated as an upstream molecule in BA-mediated FAK activation, plausibly by regulating Src activation. Altogether, these results demonstrate that elevated levels of BA increase the tumorigenic potential of PC cells by inducing FXR/FAK/c-Jun axis to upregulate MUC4 expression, which is overexpressed in pancreatic tumors and is known to be associated with progression and metastasis of PC. PMID:27185392

  6. Synergistic Cytotoxic Effect of Gold Nanoparticles and 5-Aminolevulinic Acid-Mediated Photodynamic Therapy against Skin Cancer Cells

    Mahnaz Hadizadeh

    2014-09-01

    Full Text Available Background: Photodynamic therapy (PDT is a promising therapeutic modality for the treatment of cancer and other diseases. In this study, the epidermoid carcinoma cell line A431 and the normal fibroblasts were used to investigate whether gold nanoparticles (GNPs can induce an increase in cell death during PDT using 5-aminolevulinic acid (5-ALA as a photosensitizer. Methods: Human fibroblast and A431 cells were grown in 96-well plates. The effect of GNPs on the efficacy of 5-ALA-mediated PDT (5-ALA-PDT was evaluated by comparing the effect of 5-ALA with GNPs to the effect of 5-ALA alone. Cell viability was determined by the methyl- tetrazolium assay. Results: Dark toxicity experiments showed that 5-ALA at concentrations 0.5, 1 and 2 mM had no significant effect on cell viability of both cell lines. However, treatment of cells with 5-ALA (0.5 to 2 mM and light dose of 25 Jcm-2 led to 5-10% and 31-42% decrease in cell viability of fibroblast and A431 cells respectively. The data also shows that GNPs in both the absence and the presence of light, results in a dose-dependent decrease in cell viability of both cell lines. However, the sensitivity of cancer cells to GNPs at concentrations more than 24 μg/ml was approximately 2.5- to 4-fold greater than healthy cells. Furthermore, data indicates that 5-ALA in combination with GNPs results in a synergistic reduction in viability of A431 cells. Conclusion: In summary, the findings of this study suggest that concomitant treatment with 5-ALA and GNPs may be useful in enhancing the effect of 5-ALA-PDT.

  7. Nitric Oxide Mediates 5-Aminolevulinic Acid-Induced Antioxidant Defense in Leaves of Elymus nutans Griseb. Exposed to Chilling Stress.

    Juanjuan Fu

    Full Text Available Nitric oxide (NO and 5-aminolevulinic acid (ALA are both extremely important signalling molecules employed by plants to control many aspects of physiology. In the present study, the role of NO in ALA-induced antioxidant defense in leaves of two sources of Elymus nutans Griseb. (Damxung, DX and Zhengdao, ZD was investigated. Chilling stress enhanced electrolyte leakage, accumulation of malondialdehyde (MDA, hydrogen peroxide (H2O2 and superoxide radical in two E. nutans, which were substantially alleviated by exogenous ALA and NO application. Pretreatment with NO scavenger PTIO or NOS inhibitor L-NNA alone and in combination with ALA induced enhancements in electrolyte leakage and the accumulation of MDA, H2O2 and superoxide radical in leaves of DX and ZD exposed to chilling stress, indicating that the inhibition of NO biosynthesis reduced the chilling resistance of E. nutans and the ALA-enhanced chilling resistance. Further analyses showed that ALA and NO enhanced antioxidant defense and activated plasma membrane (PM H+-ATPase and decreased the accumulation of ROS induced by chilling stress. A pronounced increase in nitric oxide synthase (NOS activity and NO release by exogenous ALA treatment was found in chilling-resistant DX plants exposed to chilling stress, while only a little increase was observed in chilling-sensitive ZD. Furthermore, inhibition of NO accumulation by PTIO or L-NNA blocked the protective effect of exogenous ALA, while both exogenous NO treatment and inhibition of endogenous NO accumulation did not induce ALA production. These results suggested that NO might be a downstream signal mediating ALA-induced chilling resistance in E. nutans.

  8. Chronically Elevated Levels of Short-Chain Fatty Acids Induce T Cell-Mediated Ureteritis and Hydronephrosis.

    Park, Jeongho; Goergen, Craig J; HogenEsch, Harm; Kim, Chang H

    2016-03-01

    Short-chain fatty acids (SCFAs) are major products of gut microbial fermentation and profoundly affect host health and disease. SCFAs generate IL-10(+) regulatory T cells, which may promote immune tolerance. However, SCFAs can also induce Th1 and Th17 cells upon immunological challenges and, therefore, also have the potential to induce inflammatory responses. Because of the seemingly paradoxical SCFA activities in regulating T cells, we investigated, in depth, the impact of elevated SCFA levels on T cells and tissue inflammation in mice. Orally administered SCFAs induced effector (Th1 and Th17) and regulatory T cells in ureter and kidney tissues, and they induced T cell-mediated ureteritis, leading to kidney hydronephrosis (hereafter called acetate-induced renal disease, or C2RD). Kidney hydronephrosis in C2RD was caused by ureteral obstruction, which was, in turn, induced by SCFA-induced inflammation in the ureteropelvic junction and proximal ureter. Oral administration of all major SCFAs, such as acetate, propionate, and butyrate, induced the disease. We found that C2RD development is dependent on mammalian target of rapamycin activation, T cell-derived inflammatory cytokines such as IFN-γ and IL-17, and gut microbiota. Young or male animals were more susceptible than old or female animals, respectively. However, SCFA receptor (GPR41 or GPR43) deficiency did not affect C2RD development. Thus, SCFAs, when systemically administered at levels higher than physiological levels, cause dysregulated T cell responses and tissue inflammation in the renal system. The results provide insights into the immunological and pathological effects of chronically elevated SCFAs. PMID:26819206

  9. CD36-and GPR120-Mediated Ca2+ Signaling in Human Taste Bud Cells Mediates Differential Responses to Fatty Acids and Is Altered in Obese Mice

    Ozdener, M. H.; Subramanian, S.; Sundaresan, S.; Šerý, Omar; Hashimoto, T.; Asakawa, Y.; Besnard, P.; Abumrad, N. A.; Khan, N. A.

    2014-01-01

    Roč. 146, č. 4 (2014), s. 995-1005. ISSN 0016-5085 Institutional support: RVO:67985904 Keywords : serotonin * linoleic acid * GLP-1 * lipids Subject RIV: ED - Physiology Impact factor: 16.716, year: 2014

  10. Gallic acid abolishes the EGFR/Src/Akt/Erk-mediated expression of matrix metalloproteinase-9 in MCF-7 breast cancer cells.

    Chen, Ying-Jung; Lin, Ku-Nan; Jhang, Li-Mei; Huang, Chia-Hui; Lee, Yuan-Chin; Chang, Long-Sen

    2016-05-25

    Several studies have revealed that natural compounds are valuable resources to develop novel agents against dysregulation of the EGF/EGFR-mediated matrix metalloproteinase-9 (MMP-9) expression in cancer cells. In view of the findings that EGF/EGFR-mediated MMP-9 expression is closely related to invasion and metastasis of breast cancer. To determine the beneficial effects of gallic acid on the suppression of breast cancer metastasis, we explored the effect of gallic acid on MMP-9 expression in EGF-treated MCF-7 breast cancer cells. Treatment with EGF up-regulated MMP-9 mRNA and protein levels in MCF-7 cells. EGF treatment induced phosphorylation of EGFR and elicited Src activation, subsequently promoting Akt/NFκB (p65) and ERK/c-Jun phosphorylation in MCF-7 cells. Activation of Akt/p65 and ERK/c-Jun was responsible for the MMP-9 up-regulation in EGF-treated cells. Gallic acid repressed the EGF-induced activation of EGFR and Src; furthermore, inactivation of Akt/p65 and ERK/c-Jun was a result of the inhibitory effect of gallic acid on the EGF-induced MMP-9 up-regulation. Over-expression of constitutively active Akt and MEK1 or over-expression of constitutively active Src eradicated the inhibitory effect of gallic acid on the EGF-induced MMP-9 up-regulation. A chromosome conformation capture assay showed that EGF induced a chromosomal loop formation in the MMP-9 promoter via NFκB/p65 and AP-1/c-Jun activation. Treatment with gallic acid, EGFR inhibitor, or Src inhibitor reduced DNA looping. Taken together, our data suggest that gallic acid inhibits the activation of EGFR/Src-mediated Akt and ERK, leading to reduced levels of p65/c-Jun-mediated DNA looping and thus inhibiting MMP-9 expression in EGF-treated MCF-7 cells. PMID:27087131

  11. Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

    Klingelhoeffer Christoph

    2012-05-01

    Full Text Available Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100 mmol/L. The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. Methods Effective concentration (EC50 values, which indicate the concentration of ascorbic acid that reduced the number of viable cells by 50%, were detected with the crystal violet assay. The level of intracellular catalase protein and enzyme activity was determined. Expression of catalase was silenced by catalase-specific short hairpin RNA (sh-RNA in BT-20 breast carcinoma cells. Oxidative cell stress induced apoptosis was measured by a caspase luminescent assay. Results The tested human cancer cell lines demonstrated obvious differences in their resistance to ascorbic acid mediated oxidative cell stress. Forty-five percent of the cell lines had an EC50 > 20 mmol/L and fifty-five percent had an EC50 50 of 2.6–5.5 mmol/L, glioblastoma cells were the most susceptible cancer cell lines analysed in this study. A correlation between catalase activity and the susceptibility to ascorbic acid was observed. To study the possible protective role of catalase on the resistance of cancer cells to oxidative cell stress, the expression of catalase in the breast carcinoma cell line BT-20, which cells were highly resistant to the exposure to ascorbic acid (EC50: 94,9 mmol/L, was silenced with specific sh-RNA. The effect was that catalase-silenced BT-20 cells (BT-20 KD-CAT became more susceptible to high concentrations of ascorbic acid (50 and 100 mmol/L. Conclusions Fifty-five percent of the human cancer cell lines tested were unable to protect themselves

  12. TGF-β-SMAD3 signaling mediates hepatic bile acid and phospholipid metabolism following lithocholic acid-induced liver injury[S

    Matsubara, Tsutomu; Tanaka, Naoki; Sato, Misako; Kang, Dong Wook; Krausz, Kristopher W.; Flanders, Kathleen C.; Ikeda, Kazuo; Luecke, Hans; Wakefield, Lalage M.; Frank J. Gonzalez

    2012-01-01

    Transforming growth factor-β (TGFβ) is activated as a result of liver injury, such as cholestasis. However, its influence on endogenous metabolism is not known. This study demonstrated that TGFβ regulates hepatic phospholipid and bile acid homeostasis through MAD homolog 3 (SMAD3) activation as revealed by lithocholic acid-induced experimental intrahepatic cholestasis. Lithocholic acid (LCA) induced expression of TGFB1 and the receptors TGFBR1 and TGFBR2 in the liver. In addition, immunohisto...

  13. Endocannabinoids may mediate the ability of (n-3) fatty acids to reduce ectopic fat and inflammatory mediators in obese Zucker rats.

    Batetta, Barbara; Griinari, Mikko; Carta, Gianfranca; Murru, Elisabetta; Ligresti, Alessia; Cordeddu, Lina; Giordano, Elena; Sanna, Francesca; Bisogno, Tiziana; Uda, Sabrina; Collu, Maria; Bruheim, Inge; Di Marzo, Vincenzo; Banni, Sebastiano

    2009-08-01

    Dietary (n-3) long-chain PUFA [(n-3) LCPUFA] ameliorate several metabolic risk factors for cardiovascular diseases, although the mechanisms of these beneficial effects are not fully understood. In this study, we compared the effects of dietary (n-3) LCPUFA, in the form of either fish oil (FO) or krill oil (KO) balanced for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content, with a control (C) diet containing no EPA and DHA and similar contents of oleic, linoleic, and alpha-linolenic acids, on ectopic fat and inflammation in Zucker rats, a model of obesity and related metabolic dysfunction. Diets were fed for 4 wk. Given the emerging evidence for an association between elevated endocannabinoid concentrations and metabolic syndrome, we also measured tissue endocannabinoid concentrations. In (n-3) LCPUFA-supplemented rats, liver triglycerides and the peritoneal macrophage response to an inflammatory stimulus were significantly lower than in rats fed the control diet, and heart triglycerides were lower, but only in KO-fed rats. These effects were associated with a lower concentration of the endocannabinoids, anandamide and 2-arachidonoylglycerol, in the visceral adipose tissue and of anandamide in the liver and heart, which, in turn, was associated with lower levels of arachidonic acid in membrane phospholipids, but not with higher activity of endocannabinoid-degrading enzymes. Our data suggest that the beneficial effects of a diet enriched with (n-3) LCPUFA are the result of changes in membrane fatty acid composition. The reduction of substrates for inflammatory molecules and endocannabinoids may account for the dampened inflammatory response and the physiological reequilibration of body fat deposition in obese rats. PMID:19549757

  14. Maize death acids, 9-lipoxygenase derived cyclopente(a)nones, display activity as cytotoxic phytoalexins and transcriptional mediators

    Plant damage promotes the interaction of lipoxygenases (LOX) with fatty acids yielding 9-hydroperoxides, 13-hydroperoxides and complex arrays of oxylipins. The action of 13-LOX on linolenic acid enables production of 12-oxo-phytodienoic acid (12-OPDA) and its downstream products, termed jasmonates. ...

  15. Chaperone protein HYPK interacts with the first 17 amino acid region of Huntingtin and modulates mutant HTT-mediated aggregation and cytotoxicity

    Choudhury, Kamalika Roy [Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Centre for Neuroscience, Indian Institute of Science, Bangalore 560012 (India); Bhattacharyya, Nitai P., E-mail: nitai_sinp@yahoo.com [Biomedical Genomics Centre, PG Polyclinic Building, 5, Suburbun Hospital Road, Kolkata 700020 (India)

    2015-01-02

    Highlights: • HYPK reduces mutant HTT-mediated aggregate formation and cytotoxicity. • Interaction of HYPK with HTT requires N-terminal 17 amino acid of HTT (HTT-N17). • Deletion of HTT-N17 leads to SDS-soluble, smaller, nuclear aggregates. • These smaller aggregates do not associate with HYPK and are more cytotoxic. • Maybe, interaction of HYPK with amphipathic HTT-N17 block HTT aggregate formation. - Abstract: Huntington’s disease is a polyglutamine expansion disorder, characterized by mutant HTT-mediated aggregate formation and cytotoxicity. Many reports suggests roles of N-terminal 17 amino acid domain of HTT (HTT-N17) towards subcellular localization, aggregate formation and subsequent pathogenicity induced by N-terminal HTT harboring polyQ stretch in pathogenic range. HYPK is a HTT-interacting chaperone which can reduce N-terminal mutant HTT-mediated aggregate formation and cytotoxicity in neuronal cell lines. However, how HYPK interacts with N-terminal fragment of HTT remained unknown. Here we report that specific interaction of HYPK with HTT-N17 is crucial for the chaperone activity of HYPK. Deletion of HTT-N17 leads to formation of tinier, SDS-soluble nuclear aggregates formed by N-terminal mutant HTT. The increased cytotoxicity imparted by these tiny aggregates might be contributed due to loss of interaction with HYPK.

  16. Chaperone protein HYPK interacts with the first 17 amino acid region of Huntingtin and modulates mutant HTT-mediated aggregation and cytotoxicity

    Highlights: • HYPK reduces mutant HTT-mediated aggregate formation and cytotoxicity. • Interaction of HYPK with HTT requires N-terminal 17 amino acid of HTT (HTT-N17). • Deletion of HTT-N17 leads to SDS-soluble, smaller, nuclear aggregates. • These smaller aggregates do not associate with HYPK and are more cytotoxic. • Maybe, interaction of HYPK with amphipathic HTT-N17 block HTT aggregate formation. - Abstract: Huntington’s disease is a polyglutamine expansion disorder, characterized by mutant HTT-mediated aggregate formation and cytotoxicity. Many reports suggests roles of N-terminal 17 amino acid domain of HTT (HTT-N17) towards subcellular localization, aggregate formation and subsequent pathogenicity induced by N-terminal HTT harboring polyQ stretch in pathogenic range. HYPK is a HTT-interacting chaperone which can reduce N-terminal mutant HTT-mediated aggregate formation and cytotoxicity in neuronal cell lines. However, how HYPK interacts with N-terminal fragment of HTT remained unknown. Here we report that specific interaction of HYPK with HTT-N17 is crucial for the chaperone activity of HYPK. Deletion of HTT-N17 leads to formation of tinier, SDS-soluble nuclear aggregates formed by N-terminal mutant HTT. The increased cytotoxicity imparted by these tiny aggregates might be contributed due to loss of interaction with HYPK

  17. RETINOIC ACID NUCLEAR RECEPTOR α(RARα) PLAYS A MAJOR ROLE IN RETINOID-MEDIATED INHIBITIONOF GROWTH IN HUMAN BREAST CARCINOMA CELLS

    邵志敏; 余黎明; 沈镇宙; JosephA.Fontana

    1996-01-01

    Retinoids mediate their actions via retinoic acid receptors (RARα) and retinoid X receptors (RXRs). Each of class of these nuclear retinoid receptor is further subdivided into three species narnely α,βandγ,Recently studies demonstrated that estrogen receptor(ER)-positive human breast cancer(HBC) cell lines are sensitive and ER-negative cell lines are resistant to growth inhibitory effeces of retinoic acid(RA).In this study,we found that only RARα mRNA levels was strongly correlated with ER-status.To further inwestigate the major role of RARα in retinoid-mediated inhibition of growth,we transfected RARα cDNA into two RA-resistant ER-negative HBC cell lines.Analysis of different clonal populations of RARα transfectants from each cell line revealed growth inhibition by retinoids.Our results demonstrated that RARα plays a major role in mediating retinoids inhibition of growth in HBC cells and sdequate levels of RARα are required for such an effect.

  18. A new role for an old enzyme: Nitrate reductase-mediated nitric oxide generation is required for abscisic acid-induced stomatal closure in Arabidopsis thaliana

    Desikan, Radhika; Griffiths, Rachael; Hancock, John; Neill, Steven

    2002-01-01

    The plant hormone abscisic acid (ABA), synthesized in response to water-deficit stress, induces stomatal closure via activation of complex signaling cascades. Recent work has established that nitric oxide (NO) is a key signaling molecule mediating ABA-induced stomatal closure. However, the biosynthetic origin of NO in guard cells has not yet been resolved. Here, we provide pharmacological, physiological, and genetic evidence that NO synthesis in Arabidopsis guard cells is mediated by the enzyme nitrate reductase (NR). Guard cells of wild-type Arabidopsis generate NO in response to treatment with ABA and nitrite, a substrate for NR. Moreover, NR-mediated NO synthesis is required for ABA-induced stomatal closure. However, in the NR double mutant, nia1, nia2 that has diminished NR activity, guard cells do not synthesize NO nor do the stomata close in response to ABA or nitrite, although stomatal opening is still inhibited by ABA. Furthermore, by using the ABA-insensitive (ABI) abi1–1 and abi2–1 mutants, we show that the ABI1 and ABI2 protein phosphatases are downstream of NO in the ABA signal-transduction cascade. These data demonstrate a previously uncharacterized signaling role for NR, that of mediating ABA-induced NO synthesis in Arabidopsis guard cells. PMID:12446847

  19. Specialized Pro-Resolving Mediators from Omega-3 Fatty Acids Improve Amyloid-β Phagocytosis and Regulate Inflammation in Patients with Minor Cognitive Impairment.

    Fiala, Milan; Terrando, Niccolo; Dalli, Jesmond

    2015-01-01

    In this review we discuss the immunopathology of Alzheimer's disease (AD) and recent advances in the prevention of minor cognitive impairment (MCI) by nutritional supplementation with omega-3 fatty acids. Defective phagocytosis of amyloid-β (Aβ) and abnormal inflammatory activation of peripheral blood mononuclear cells (PBMCs) are the two key immune pathologies of MCI and AD patients. The phagocytosis of Aβ by PBMCs of MCI and AD patients is universally defective and the inflammatory gene transcription is heterogeneously deregulated in comparison to normal subjects. Recent studies have discovered a cornucopia of beneficial anti-inflammatory and pro-resolving effects of the specialized proresolving mediators (SPMs) resolvins, protectins, maresins, and their metabolic precursors. Resolvin D1 and other mediators switch macrophages from an inflammatory to a tissue protective/pro-resolving phenotype and increase phagocytosis of Aβ. In a recent study of AD and MCI patients, nutritional supplementation by omega-3 fatty acids individually increased resolvin D1, improved Aβ phagocytosis, and regulated inflammatory genes toward a physiological state, but only in MCI patients. Our studies are beginning to dissect positive factors (adherence to Mediterranean diet with omega-3 and exercise) and negative factors (high fat diet, infections, cancer, and surgeries) in each patient. The in vitro and in vivo effects of omega-3 fatty acids and SPMs suggest that defective phagocytosis and chronic inflammation are related to defective production and/or defective signaling by SPMs in immune cells. PMID:26401996

  20. P-type ATPase TAT-2 negatively regulates monomethyl branched-chain fatty acid mediated function in post-embryonic growth and development in C. elegans.

    Emylie Seamen

    2009-08-01

    Full Text Available Monomethyl branched-chain fatty acids (mmBCFAs are essential for Caenorhabditis elegans growth and development. To identify factors acting downstream of mmBCFAs for their function in growth regulation, we conducted a genetic screen for suppressors of the L1 arrest that occurs in animals depleted of the 17-carbon mmBCFA C17ISO. Three of the suppressor mutations defined an unexpected player, the P-type ATPase TAT-2, which belongs to the flippase family of proteins that are implicated in mediating phospholipid bilayer asymmetry. We provide evidence that TAT-2, but not other TAT genes, has a specific role in antagonizing the regulatory activity of mmBCFAs in intestinal cells. Interestingly, we found that mutations in tat-2 also suppress the lethality caused by inhibition of the first step in sphingolipid biosynthesis. We further showed that the fatty acid side-chains of glycosylceramides contain 20%-30% mmBCFAs and that this fraction is greatly diminished in the absence of mmBCFA biosynthesis. These results suggest a model in which a C17ISO-containing sphingolipid may mediate the regulatory functions of mmBCFAs and is negatively regulated by TAT-2 in intestinal cells. This work indicates a novel connection between a P-type ATPase and the critical regulatory function of a specific fatty acid.

  1. Acetylsalicylic Acid Reduces the Severity of Dextran Sodium Sulfate-Induced Colitis and Increases the Formation of Anti-Inflammatory Lipid Mediators

    Thomas Köhnke

    2013-01-01

    Full Text Available The role of non-steroidal anti-inflammatory drugs in inflammatory bowel disease is controversial, as they have been implicated in disease aggravation. Different from other cyclooxygenase inhibitors, acetylsalicylic acid (ASA enhances the formation of anti-inflammatory and proresolution lipoxins derived from arachidonic acid as well as resolvins from omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA. In this study, we examined the effect of ASA on murine dextran sodium sulfate colitis. A mouse magnetic resonance imaging (MRI protocol and post mortem assessment were used to assess disease severity, and lipid metabolites were measured using liquid chromatography-coupled tandem mass spectrometry. Decreased colitis activity was demonstrated by phenotype and MRI assessment in mice treated with ASA, and confirmed in postmortem analysis. Analysis of lipid mediators showed sustained formation of lipoxin A4 and an increase of DHA-derived 17-hydroxydocosahexaenoic acid (17-HDHA after treatment with ASA. Furthermore, in vitro experiments in RAW264.7 murine macrophages demonstrated significantly increased phagocytosis activity after incubation with 17-HDHA, supporting its proresolution effect. These results show a protective effect of ASA in a murine colitis model and could give a rationale for a careful reassessment of ASA therapy in patients with inflammatory bowel disease and particularly ulcerative colitis, possibly combined with DHA supplementation.

  2. Enzyme-mediated bacterial biodegradation of an azo dye (C.I. Acid blue 113): reuse of treated dye wastewater in post-tanning operations.

    Senthilvelan, T; Kanagaraj, J; Panda, R C

    2014-11-01

    "Dyeing" is a common practice used to color the hides during the post-tanning operations in leather processing generating plenty of wastewater. The waste stream containing dye as pollutant is severely harmful to living beings. An azo dye (C.I. Acid Blue 113) has been biodegraded effectively by bacterial culture mediated with azoreductase enzyme to reduce the pollution load in the present investigation. The maximum rate of dye degradation was found to be 96 ± 4 and 92 ± 4 % for the initial concentrations of 100 and 200 mg/l, respectively. The enzyme activity was measured using NADH as a substrate. Fourier transform infrared spectroscopy (FT-IR) analysis was confirmed that the transformation of azo linkage could be transformed into N2 or NH3 or incorporated into complete biomass. Breaking down of dye molecules to various metabolites (such as aniline, naphthalene-1,4-diamine, 3-aminobenzenesulfonic acid, naphthalene-1-sulfonic acid, 8-aminonaphthalene-1-sulfonic acid, 5,8-diaminonaphthalene-1-sulfonic acid) was confirmed by gas chromatography and mass spectra (GC-MS) and mass (electrospray ionization (ESI)) spectra analysis. The treated wastewater could be reused for dyeing operation in the leather processing, and the properties of produced leather were evaluated by conventional methods that revealed to have improved dye penetration into the grain layer of experimental leather sample and resulted in high levelness of dyeing, which helps to obtain the desired smoothness and soft leather properties. PMID:25163883

  3. A host-microbiome interaction mediates the opposing effects of omega-6 and omega-3 fatty acids on metabolic endotoxemia

    Kaliannan, Kanakaraju; Wang, Bin; Li, Xiang-Yong; Kim, Kui-Jin; Kang, Jing X.

    2015-01-01

    Metabolic endotoxemia, commonly derived from gut dysbiosis, is a primary cause of chronic low grade inflammation that underlies many chronic diseases. Here we show that mice fed a diet high in omega-6 fatty acids exhibit higher levels of metabolic endotoxemia and systemic low-grade inflammation, while transgenic conversion of tissue omega-6 to omega-3 fatty acids dramatically reduces endotoxemic and inflammatory status. These opposing effects of tissue omega-6 and omega-3 fatty acids can be e...

  4. Isomerization of all-(E)-Retinoic Acid Mediated by Carbodiimide Activation - Synthesis of ATRA Ether Lipid Conjugates

    Christensen, Mikkel Stochkendahl; Pedersen, Palle Jacob; Andresen, Thomas Lars;

    2010-01-01

    Treatment of the lysolipid 1-O-hexadecyl-sn-phosphatidylcholine with all-(E)-retinoic acid, DCC and DMAP resulted in poor acylation and caused (Z)/(E) isomerization of the alpha-beta double bond. In the presence of a proton source, the carbodiimide-activated all-(E)-retinoic acid undergoes fast...... isomerization to give a final mixture of (13E)/(13Z) isomers in a 3:1 ratio. Similar treatment of (13Z)-retinoic acid leads to the same isomer ratio. The isomerization was circumvented successfully by using a Mitsunobu reaction, which provided an efficient synthesis of all-(E)-retinoic acid sn-2-conjugated to...

  5. Insight into 2α-Chloro-2′(2′,6′)-(Di)Halogenopicropodophyllotoxins Reacting with Carboxylic Acids Mediated by BF3·Et2O

    Lingling Fan; Xiaoyan Zhi; Zhiping Che; Hui Xu

    2015-01-01

    Stereospecific nucleophilic substitution at the C-4α position of 2α-chloro-2′(2′,6′)-(di)halogenopicropodophyllotoxin derivatives with carboxylic acids mediated by BF3·Et2O was described. Interestingly, this stereoselective products were completely controlled by the reaction time. That is, if the reaction time was prolonged to 24.5–31 h, the resulting compounds were all transformed into the unusual C-ring aromatization products. Additionally, it demonstrated that BF3·Et2O and reaction tempera...

  6. Gambogic acid covalently modifies IκB-kinase-β subunit to mediate suppression of lipopolysaccharide-induced activation of NF-κB in macrophages*

    Palempalli, Umamaheshwari D.; Gandhi, Ujjawal; Kalantari, Parisa; Vunta, Hema; Arner, Ryan J.; Narayan, Vivek; Ravindran, Anand; Prabhu, K. Sandeep

    2009-01-01

    Gambogic acid (GA) is a polyprenylated xanthone abundant in the resin of Garcinia morella and G. hanburyi with a long history of use as a complementary and alternative medicine. The anti-tumor activity of GA has been well demonstrated and is thought to arise partly from the associated anti-inflammatory activity. Recent studies have indicated that the anti-tumor activity of GA is mediated by its ligation of the transferrin receptor TfR1. Since the cellular expression of TfR1 is down-regulated ...

  7. Constitutive Androstane Receptor-Mediated Changes in Bile Acid Composition Contributes to Hepatoprotection from Lithocholic Acid-Induced Liver Injury in MiceS⃞

    Beilke, Lisa D.; Aleksunes, Lauren M.; Holland, Ricky D; Besselsen, David G; Beger, Rick D.; Klaassen, Curtis D.; Cherrington, Nathan J.

    2009-01-01

    Pharmacological activation of the constitutive androstane receptor (CAR) protects the liver during cholestasis. The current study evaluates how activation of CAR influences genes involved in bile acid biosynthesis as a mechanism of hepatoprotection during bile acid-induced liver injury. CAR activators phenobarbital (PB) and 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) or corn oil (CO) were administered to C57BL/6 wild-type (WT) and CAR knockout (CAR-null) mice ...

  8. TORC1 Inhibits GSK3-Mediated Elo2 Phosphorylation to Regulate Very Long Chain Fatty Acid Synthesis and Autophagy

    Zimmermann, Christine; Santos, Aline; Gable, Kenneth; Epstein, Sharon; Gururaj, Charulatha; Chymkowitch, Pierre; Pultz, Dennis; Rødkær, Steven V; Clay, Lorena; Bjørås, Magnar; Barral, Yves; Chang, Amy; Færgeman, Nils J.; Dunn, Teresa M; Riezman, Howard; Enserink, Jorrit M

    2013-01-01

    Very long chain fatty acids (VLCFAs) are essential fatty acids with multiple functions, including ceramide synthesis. Although the components of the VLCFA biosynthetic machinery have been elucidated, how their activity is regulated to meet the cell's metabolic demand remains unknown. The goal of ...

  9. Extracellular loop 2 of the free Fatty Acid receptor 2 mediates allosterism of a phenylacetamide ago-allosteric modulator

    Smith, Nicola J; Ward, Richard J; Stoddart, Leigh A; Hudson, Brian D; Kostenis, Evi; Ulven, Trond; Morris, Joanne C; Tränkle, Christian; Tikhonova, Irina G; Adams, David R; Milligan, Graeme

    2011-01-01

    Allosteric agonists are powerful tools for exploring the pharmacology of closely related G protein-coupled receptors that have nonselective endogenous ligands, such as the short chain fatty acids at free fatty acid receptors 2 and 3 (FFA2/GPR43 and FFA3/GPR41, respectively). We explored the molec...

  10. Ammonium regulates embryogenic potential in Cucurbita pepo through pH-mediated changes in endogenous auxin and abscisic acid

    Pěnčík, Aleš; Turečková, Veronika; Paulisić, S.; Rolčík, Jakub; Strnad, Miroslav; Mihaljević, S.

    2015-01-01

    Roč. 122, č. 1 (2015), s. 89-100. ISSN 0167-6857 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional support: RVO:61389030 Keywords : Abscisic acid * Ammonium * Indole-3-acetic acid Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.125, year: 2014