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Sample records for acid regulates ozone-induced

  1. Uric acid protects membranes and linolenic acid from ozone-induced oxidation.

    PubMed

    Meadows, J; Smith, R C; Reeves, J

    1986-05-29

    Aqueous preparations of linolenic acid, bovine serum albumin, and bovine erythrocyte membrane fragments were bubbled with ozone in the presence or absence of uric acid. Ozonation of the membrane fragments or the bovine serum albumin did not result in protein degradation. After 15 min of ozonation, the absorbance of the thiobarbituric acid-reactive material increased by 0.34 in the linolenic acid preparation and by 0.08 in the suspension of membrane fragments. In the presence of uric acid, these changes in absorbance were reduced to 0.14 for the fatty acid and to 0.01 for the membrane fragments. This result indicates that uric acid protects lipids from ozone-induced oxidation.

  2. Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

    PubMed

    Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R

    2000-09-01

    Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

  3. Uric acid protects erythrocytes from ozone-induced changes.

    PubMed

    Meadows, J; Smith, R C

    1987-08-01

    Uric acid effectively reduced hemolysis and methemoglobin formation in bovine and swine erythrocytes bubbled with ozone in vitro. In bovine erythrocytes, formation of thiobarbituric acid-reactive material was inhibited by uric acid, but there was little immediate protection for the swine cells. Antioxidant protection was due to preferential degradation of the uric acid by ozone. These results provide evidence to support the hypothesis that in plasma, uric acid can provide antioxidant protection for erythrocytes.

  4. Abscisic acid plays critical role in ozone-induced taxol production of Taxus chinensis suspension cell cultures.

    PubMed

    Xu, Maojun; Jin, Haihong; Dong, Jufang; Zhang, Ming; Xu, Xiangbin; Zhou, Ting

    2011-01-01

    Exposure to ozone induced a rapid increase in the levels of the phytohormone abscisic acid (ABA) and sequentially followed by the enhancement of Taxol production in suspension cell cultures of Taxus chinensis. The observed increases in ABA and Taxol were dependent on the concentration of ozone applied to T. chinensis cell cultures. To examine the role of ABA in ozone-induced Taxol production, we pretreated the cells with ABA biosynthesis inhibitor fluridone to abolish ozone-triggered ABA generation and assayed the effect of fluridone on ozone-induced Taxol production. The results showed that pretreatment of the cells with fluridone not only suppressed the ozone-triggered ABA generation but also blocked the ozone-induced Taxol production. Moreover, our data indicate that the effect of ABA on Taxol production of T. chinensis cell cultures is dose-dependent. Interestingly, the suppression of fluridone on ozone-induced Taxol production was reversed by exogenous application of low dose of ABA, although treatment of low dose ABA alone had no effect on Taxol production of the cells. Together, the data indicated that ozone was an efficient elicitor for improving Taxol production of plant cell cultures. Furthermore, we demonstrated that ABA played critical roles in ozone-induced Taxol production of T. chinensis suspension cell cultures. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

  5. Involvement of abscisic acid in ozone-induced puerarin production of Pueraria thomsnii Benth. suspension cell cultures.

    PubMed

    Sun, Lina; Su, Hu; Zhu, Yun; Xu, Maojun

    2012-01-01

    Exposure to ozone induced a rapid increase in the levels of the sesquiterpene phytohormone abscisic acid (ABA) and the isoflavone puerarin in suspension cell cultures of Pueraria thomsnii Benth. The observed increases in ABA and puerarin were dependent on the concentration of ozone applied to P. thomsnii cell cultures. In order to examine the role of ABA in ozone-induced puerarin production, cell suspensions were pretreated with the ABA biosynthetic inhibitor fluridone. Following ozone exposure, fluridone treatment suppressed ABA accumulation suggesting ABA was normally synthesized de novo through the carotenoid pathway. Fluridone also blocked ozone-induced puerarin production, which could be reversed through application of exogenous ABA. However, in the absence of ozone, ABA itself had no effect on puerarin accumulation in the suspension cells. Taken together, the data indicate that ozone is an efficient elicitor of puerarin production and may be particularly applicable for improving puerarin production in plant cell cultures. Furthermore, we demonstrate that ABA is one factor associated with ozone-induced puerarin production in P. thomsnii cell cultures.

  6. A role for oxalic acid generation in ozone-induced signallization in Arabidopis cells.

    PubMed

    Tran, Daniel; Kadono, Takashi; Molas, Maria Lia; Errakhi, Rafik; Briand, Joël; Biligui, Bernadette; Kawano, Tomonori; Bouteau, François

    2013-03-01

    Ozone (O(3) ) is an air pollutant with an impact increasingly important in our industrialized world. It affects human health and productivity in various crops. We provide the evidences that treatment of Arabidopsis thaliana with O(3) results in ascorbate-derived oxalic acid production. Using cultured cells of A. thaliana as a model, here we further showed that oxalic acid induces activation of anion channels that trigger depolarization of the cell, increase in cytosolic Ca(2+) concentration, generation of reactive oxygen species and cell death. We confirmed that O(3) reacts with ascorbate in the culture, thus resulting in production of oxalic acid and this could be part of the O(3) -induced signalling pathways that trigger programmed cell death. © 2012 Blackwell Publishing Ltd.

  7. α-Tocopherol/Gallic Acid Cooperation in the Protection of Galactolipids Against Ozone-Induced Oxidation.

    PubMed

    Rudolphi-Skórska, Elżbieta; Filek, Maria; Zembala, Maria

    2016-04-01

    The protective ability of α-tocopherol (TOH) and gallic acid (GA) acting simultaneously at the moment of oxidizer application was evaluated by determination of galactolipid layers' oxidation degree. Addition of GA resulted in a significant decrease of ozone-derived radicals shifting the threshold of lipid sensitivity by an amount approximately corresponding to the GA intake in bulk reaction with ozone. TOH presence in lipid layers results in a change of the role of GA which additionally may be involved in the reduction of tocopheroxyl radical formed during oxidation. This leads to a decrease in effectiveness of GA in diminishing the amount of ozone radicals. Such an effect was not observed for mixed layers containing galactolipid and pre-oxidized tocopherol where the ozone threshold level was associated with a stoichiometry of GA + O3 reaction. It was concluded that probably subsequent transformations of tocopheroxyl radical to less reactive forms prevent its reaction with GA the entire quantity of which is used for radicals scavenging. This result shows the role of time parameter in systems where substrates are engaged in various reactions taking place simultaneously. The inactivation of 1,1-diphenyl-2-picrylhydrazyl radical by studied antioxidants in homogeneous system confirmed observations made on the basis of lipid layer properties indicating their antagonistic action (at least at studied conditions). Formation of layers in post-oxidation situation did not depend whether tocopherol was oxidized during oxidation of lipid/tocopherol mixture or was introduced as pre-oxidized. This may be interpreted as indication that products of tocopherol oxidation may stabilize lipid layers.

  8. Regulation of ozone-induced lung inflammation and injury by the β-galactoside-binding lectin galectin-3

    SciTech Connect

    Sunil, Vasanthi R.; Francis, Mary; Vayas, Kinal N.; Cervelli, Jessica A.; Choi, Hyejeong; Laskin, Jeffrey D.; Laskin, Debra L.

    2015-04-15

    Macrophages play a dual role in ozone toxicity, contributing to both pro- and anti-inflammatory processes. Galectin-3 (Gal-3) is a lectin known to regulate macrophage activity. Herein, we analyzed the role of Gal-3 in the response of lung macrophages to ozone. Bronchoalveolar lavage (BAL) and lung tissue were collected 24–72 h after exposure (3 h) of WT and Gal-3{sup -/-} mice to air or 0.8 ppm ozone. In WT mice, ozone inhalation resulted in increased numbers of proinflammatory (Gal-3{sup +}, iNOS{sup +}) and anti-inflammatory (MR-1{sup +}) macrophages in the lungs. While accumulation of iNOS{sup +} macrophages was attenuated in Gal-3{sup -/-} mice, increased numbers of enlarged MR-1{sup +} macrophages were noted. This correlated with increased numbers of macrophages in BAL. Flow cytometric analysis showed that these cells were CD11b{sup +} and consisted mainly (> 97%) of mature (F4/80{sup +}CD11c{sup +}) proinflammatory (Ly6GLy6C{sup hi}) and anti-inflammatory (Ly6GLy6C{sup lo}) macrophages. Increases in both macrophage subpopulations were observed following ozone inhalation. Loss of Gal-3 resulted in a decrease in Ly6C{sup hi} macrophages, with no effect on Ly6C{sup lo} macrophages. CD11b{sup +}Ly6G{sup +}Ly6C{sup +} granulocytic (G) and monocytic (M) myeloid derived suppressor cells (MDSC) were also identified in the lung after ozone. In Gal-3{sup -/-} mice, the response of G-MDSC to ozone was attenuated, while the response of M-MDSC was heightened. Changes in inflammatory cell populations in the lung of ozone treated Gal-3{sup -/-} mice were correlated with reduced tissue injury as measured by cytochrome b5 expression. These data demonstrate that Gal-3 plays a role in promoting proinflammatory macrophage accumulation and toxicity in the lung following ozone exposure. - Highlights: • Multiple monocytic-macrophage subpopulations accumulate in the lung after ozone inhalation. • Galectin-3 plays a proinflammatory role in ozone-induced lung injury. • In the

  9. Roles of Defense Hormones in the Regulation of Ozone-Induced Changes in Gene Expression and Cell Death.

    PubMed

    Xu, Enjun; Vaahtera, Lauri; Brosché, Mikael

    2015-12-07

    Apoplast, the diffusional space between plant cell plasma membranes, is an important medium for signaling within and between the cells. Apoplastic reactive oxygen species (ROS) are crucial signaling molecules in various biological processes. ROS signaling is interconnected with the response to several hormones, including jasmonic acid (JA), salicylic acid (SA) and ethylene. Using ozone (O3) to activate apoplastic ROS signaling, we performed global and targeted analysis of transcriptional changes and cell death assays to dissect the contribution of hormone signaling and various transcription factors (TFs) in the regulation of gene expression and cell death. The contributions of SA, JA, and ethylene were assessed through analysis of single, double, and triple mutants deficient in biosynthesis or signaling for all three hormones. Even in the triple mutant, the global gene expression responses to O3 were mostly similar to the wild-type. Cell death in the JA receptor mutant coi1-16 was suppressed by impairment of the NADPH oxidase RBOHF, suggesting a role for a ROS signal in limiting the spread of cell death. In response to apoplastic ROS, there is not a single signaling pathway that regulates gene expression or cell death. Instead, several pathways regulate the apoplastic ROS response via combinatorial or overlapping mechanisms. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  10. ROCK insufficiency attenuates ozone-induced airway hyperresponsiveness in mice.

    PubMed

    Kasahara, David I; Mathews, Joel A; Park, Chan Y; Cho, Youngji; Hunt, Gabrielle; Wurmbrand, Allison P; Liao, James K; Shore, Stephanie A

    2015-10-01

    Ozone causes airway hyperresponsiveness (AHR) and pulmonary inflammation. Rho kinase (ROCK) is a key regulator of smooth muscle cell contraction and inflammatory cell migration. To determine the contribution of the two ROCK isoforms ROCK1 and ROCK2 to ozone-induced AHR, we exposed wild-type, ROCK1(+/-), and ROCK2(+/-) mice to air or ozone (2 ppm for 3 h) and evaluated mice 24 h later. ROCK1 or ROCK2 haploinsufficiency did not affect airway responsiveness in air-exposed mice but significantly reduced ozone-induced AHR, with a greater reduction in ROCK2(+/-) mice despite increased bronchoalveolar lavage (BAL) inflammatory cells in ROCK2(+/-) mice. Compared with wild-type mice, ozone-induced increases in BAL hyaluronan, a matrix protein implicated in ozone-induced AHR, were lower in ROCK1(+/-) but not ROCK2(+/-) mice. Ozone-induced increases in other inflammatory moieties reported to contribute to ozone-induced AHR (IL-17A, osteopontin, TNFα) were not different in wild-type vs. ROCK1(+/-) or ROCK2(+/-) mice. We also observed a dose-dependent reduction in ozone-induced AHR after treatment with the ROCK1/ROCK2 inhibitor fasudil, even though fasudil was administered after induction of inflammation. Ozone increased pulmonary expression of ROCK2 but not ROCK1 or RhoA. A ROCK2 inhibitor, SR3677, reduced contractile forces in primary human airway smooth muscle cells, confirming a role for ROCK2 in airway smooth muscle contraction. Our results demonstrate that ozone-induced AHR requires ROCK. Whereas ROCK1-dependent changes in hyaluronan may contribute to ROCK1's role in O3-induced AHR, the role of ROCK2 is downstream of inflammation, likely at the level of airway smooth muscle contraction. Copyright © 2015 the American Physiological Society.

  11. ROCK insufficiency attenuates ozone-induced airway hyperresponsiveness in mice

    PubMed Central

    Mathews, Joel A.; Park, Chan Y.; Cho, Youngji; Hunt, Gabrielle; Wurmbrand, Allison P.; Liao, James K.; Shore, Stephanie A.

    2015-01-01

    Ozone causes airway hyperresponsiveness (AHR) and pulmonary inflammation. Rho kinase (ROCK) is a key regulator of smooth muscle cell contraction and inflammatory cell migration. To determine the contribution of the two ROCK isoforms ROCK1 and ROCK2 to ozone-induced AHR, we exposed wild-type, ROCK1+/−, and ROCK2+/− mice to air or ozone (2 ppm for 3 h) and evaluated mice 24 h later. ROCK1 or ROCK2 haploinsufficiency did not affect airway responsiveness in air-exposed mice but significantly reduced ozone-induced AHR, with a greater reduction in ROCK2+/− mice despite increased bronchoalveolar lavage (BAL) inflammatory cells in ROCK2+/− mice. Compared with wild-type mice, ozone-induced increases in BAL hyaluronan, a matrix protein implicated in ozone-induced AHR, were lower in ROCK1+/− but not ROCK2+/− mice. Ozone-induced increases in other inflammatory moieties reported to contribute to ozone-induced AHR (IL-17A, osteopontin, TNFα) were not different in wild-type vs. ROCK1+/− or ROCK2+/− mice. We also observed a dose-dependent reduction in ozone-induced AHR after treatment with the ROCK1/ROCK2 inhibitor fasudil, even though fasudil was administered after induction of inflammation. Ozone increased pulmonary expression of ROCK2 but not ROCK1 or RhoA. A ROCK2 inhibitor, SR3677, reduced contractile forces in primary human airway smooth muscle cells, confirming a role for ROCK2 in airway smooth muscle contraction. Our results demonstrate that ozone-induced AHR requires ROCK. Whereas ROCK1-dependent changes in hyaluronan may contribute to ROCK1's role in O3-induced AHR, the role of ROCK2 is downstream of inflammation, likely at the level of airway smooth muscle contraction. PMID:26276827

  12. Regulation of ozone-induced lung inflammation and injury by the β-galactoside-binding lectin galectin-3.

    PubMed

    Sunil, Vasanthi R; Francis, Mary; Vayas, Kinal N; Cervelli, Jessica A; Choi, Hyejeong; Laskin, Jeffrey D; Laskin, Debra L

    2015-04-15

    Macrophages play a dual role in ozone toxicity, contributing to both pro- and anti-inflammatory processes. Galectin-3 (Gal-3) is a lectin known to regulate macrophage activity. Herein, we analyzed the role of Gal-3 in the response of lung macrophages to ozone. Bronchoalveolar lavage (BAL) and lung tissue were collected 24-72h after exposure (3h) of WT and Gal-3(-/-) mice to air or 0.8ppm ozone. In WT mice, ozone inhalation resulted in increased numbers of proinflammatory (Gal-3(+), iNOS(+)) and anti-inflammatory (MR-1(+)) macrophages in the lungs. While accumulation of iNOS(+) macrophages was attenuated in Gal-3(-/-) mice, increased numbers of enlarged MR-1(+) macrophages were noted. This correlated with increased numbers of macrophages in BAL. Flow cytometric analysis showed that these cells were CD11b(+) and consisted mainly (>97%) of mature (F4/80(+)CD11c(+)) proinflammatory (Ly6GLy6C(hi)) and anti-inflammatory (Ly6GLy6C(lo)) macrophages. Increases in both macrophage subpopulations were observed following ozone inhalation. Loss of Gal-3 resulted in a decrease in Ly6C(hi) macrophages, with no effect on Ly6C(lo) macrophages. CD11b(+)Ly6G(+)Ly6C(+) granulocytic (G) and monocytic (M) myeloid derived suppressor cells (MDSC) were also identified in the lung after ozone. In Gal-3(-/-) mice, the response of G-MDSC to ozone was attenuated, while the response of M-MDSC was heightened. Changes in inflammatory cell populations in the lung of ozone treated Gal-3(-/-) mice were correlated with reduced tissue injury as measured by cytochrome b5 expression. These data demonstrate that Gal-3 plays a role in promoting proinflammatory macrophage accumulation and toxicity in the lung following ozone exposure.

  13. Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

    EPA Pesticide Factsheets

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (p=0.15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not obser

  14. Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

    EPA Pesticide Factsheets

    Acute ozone exposure increases circulating stress hormones and induces peripheral metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for ozone-induced systemic metabolic effects and lung injury. Male Wistar-Kyoto rats (12 week-old) underwent total bilateral adrenalectomy (ADREX), adrenal demedullation (DEMED) or sham surgery (SHEM). After 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids and branched-chain amino acids tended to increase after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decrease in circulating WBC in SHAM was not

  15. Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

    EPA Pesticide Factsheets

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (p=0.15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not obser

  16. Ozone-Induced Rice Grain Yield Loss Is Triggered via a Change in Panicle Morphology That Is Controlled by ABERRANT PANICLE ORGANIZATION 1 Gene.

    PubMed

    Tsukahara, Keita; Sawada, Hiroko; Kohno, Yoshihisa; Matsuura, Takakazu; Mori, Izumi C; Terao, Tomio; Ioki, Motohide; Tamaoki, Masanori

    2015-01-01

    Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investigated the responses to ozone of two rice (Oryza Sativa L.) cultivars, Sasanishiki and Habataki. Sasanishiki showed ozone-induced leaf injury, but no grain yield loss. By contrast, Habataki showed grain yield loss with minimal leaf injury. A QTL associated with grain yield loss caused by ozone was identified in Sasanishiki/Habataki chromosome segment substitution lines and included the ABERRANT PANICLE ORGANIZATION 1 (APO1) gene. The Habataki allele of the APO1 locus in a near-isogenic line also resulted in grain yield loss upon ozone exposure, suggesting APO1 involvement in ozone-induced yield loss. Only a few differences in the APO1 amino acid sequences were detected between the cultivars, but the APO1 transcript level was oppositely regulated by ozone exposure: i.e., it increased in Sasanishiki and decreased in Habataki. Interestingly, the levels of some phytohormones (jasmonic acid, jasmonoyl-L-isoleucine, and abscisic acid) known to be involved in attenuation of ozone-induced leaf injury tended to decrease in Sasanishiki but to increase in Habataki upon ozone exposure. These data indicate that ozone-induced grain yield loss in Habataki is caused by a reduction in the APO1 transcript level through an increase in the levels of phytohormones that reduce leaf damage.

  17. Ozone-Induced Rice Grain Yield Loss Is Triggered via a Change in Panicle Morphology That Is Controlled by ABERRANT PANICLE ORGANIZATION 1 Gene

    PubMed Central

    Tsukahara, Keita; Sawada, Hiroko; Kohno, Yoshihisa; Matsuura, Takakazu; Mori, Izumi C.; Terao, Tomio; Ioki, Motohide; Tamaoki, Masanori

    2015-01-01

    Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investigated the responses to ozone of two rice (Oryza Sativa L.) cultivars, Sasanishiki and Habataki. Sasanishiki showed ozone-induced leaf injury, but no grain yield loss. By contrast, Habataki showed grain yield loss with minimal leaf injury. A QTL associated with grain yield loss caused by ozone was identified in Sasanishiki/Habataki chromosome segment substitution lines and included the ABERRANT PANICLE ORGANIZATION 1 (APO1) gene. The Habataki allele of the APO1 locus in a near-isogenic line also resulted in grain yield loss upon ozone exposure, suggesting APO1 involvement in ozone-induced yield loss. Only a few differences in the APO1 amino acid sequences were detected between the cultivars, but the APO1 transcript level was oppositely regulated by ozone exposure: i.e., it increased in Sasanishiki and decreased in Habataki. Interestingly, the levels of some phytohormones (jasmonic acid, jasmonoyl-L-isoleucine, and abscisic acid) known to be involved in attenuation of ozone-induced leaf injury tended to decrease in Sasanishiki but to increase in Habataki upon ozone exposure. These data indicate that ozone-induced grain yield loss in Habataki is caused by a reduction in the APO1 transcript level through an increase in the levels of phytohormones that reduce leaf damage. PMID:25923431

  18. Ozone-Induced Hypertussive Responses in Rabbits and Guinea Pigs.

    PubMed

    Clay, Emlyn; Patacchini, Riccardo; Trevisani, Marcello; Preti, Delia; Branà, Maria Pia; Spina, Domenico; Page, Clive

    2016-04-01

    Cough remains a major unmet clinical need, and preclinical animal models are not predictive for new antitussive agents. We have investigated the mechanisms and pharmacological sensitivity of ozone-induced hypertussive responses in rabbits and guinea pigs. Ozone induced a significant increase in cough frequency and a decrease in time to first cough to inhaled citric acid in both conscious guinea pigs and rabbits. This response was inhibited by the established antitussive drugs codeine and levodropropizine. In contrast to the guinea pig, hypertussive responses in the rabbit were not inhibited by bronchodilator drugs (β2 agonists or muscarinic receptor antagonists), suggesting that the observed hypertussive state was not secondary to bronchoconstriction in this species. The ozone-induced hypertussive response in the rabbit was inhibited by chronic pretreatment with capsaicin, suggestive of a sensitization of airway sensory nerve fibers. However, we could find no evidence for a role of TRPA1 in this response, suggesting that ozone was not sensitizing airway sensory nerves via activation of this receptor. Whereas the ozone-induced hypertussive response was accompanied by a significant influx of neutrophils into the airway, the hypertussive response was not inhibited by the anti-inflammatory phosphodiesterase 4 inhibitor roflumilast at a dose that clearly exhibited anti-inflammatory activity. In summary, our results suggest that ozone-induced hypertussive responses to citric acid may provide a useful model for the investigation of novel drugs for the treatment of cough, but some important differences were noted between the two species with respect to sensitivity to bronchodilator drugs. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  19. Ozone-Induced Hypertussive Responses in Rabbits and Guinea Pigs

    PubMed Central

    Clay, Emlyn; Patacchini, Riccardo; Trevisani, Marcello; Preti, Delia; Branà, Maria Pia; Spina, Domenico

    2016-01-01

    Cough remains a major unmet clinical need, and preclinical animal models are not predictive for new antitussive agents. We have investigated the mechanisms and pharmacological sensitivity of ozone-induced hypertussive responses in rabbits and guinea pigs. Ozone induced a significant increase in cough frequency and a decrease in time to first cough to inhaled citric acid in both conscious guinea pigs and rabbits. This response was inhibited by the established antitussive drugs codeine and levodropropizine. In contrast to the guinea pig, hypertussive responses in the rabbit were not inhibited by bronchodilator drugs (β2 agonists or muscarinic receptor antagonists), suggesting that the observed hypertussive state was not secondary to bronchoconstriction in this species. The ozone-induced hypertussive response in the rabbit was inhibited by chronic pretreatment with capsaicin, suggestive of a sensitization of airway sensory nerve fibers. However, we could find no evidence for a role of TRPA1 in this response, suggesting that ozone was not sensitizing airway sensory nerves via activation of this receptor. Whereas the ozone-induced hypertussive response was accompanied by a significant influx of neutrophils into the airway, the hypertussive response was not inhibited by the anti-inflammatory phosphodiesterase 4 inhibitor roflumilast at a dose that clearly exhibited anti-inflammatory activity. In summary, our results suggest that ozone-induced hypertussive responses to citric acid may provide a useful model for the investigation of novel drugs for the treatment of cough, but some important differences were noted between the two species with respect to sensitivity to bronchodilator drugs. PMID:26837703

  20. Ozone-induced inactivation of antioxidant enzymes.

    PubMed

    Lee, Yong-Ki; Mok Kim, Sang; Han, Sanghwa

    2003-10-01

    Ozone is an air pollutant that damages a variety of biomolecules. We investigated ozone-induced inactivation of three major antioxidant enzymes. Cu/Zn superoxide dismutase was inactivated by ozone in a concentration-dependent manner. The concentration of ozone for 50% inactivation was approximately 45 microM when 10 microM Cu/Zn superoxide dismutase was incubated for 30 min in the presence of ozone. SDS-polyacrylamide gel electrophoresis (PAGE) showed that the enzyme was randomly fragmented. Both ascorbate and glutathione were very effective in protecting Cu/Zn superoxide dismutase from ozone-induced inactivation. The other two enzymes, catalase and glutathione peroxidase, were much more resistant to ozone than Cu/Zn superoxide dismutase. The ozone concentrations for 50% inactivation of 10 microM catalase and glutathione peroxidase were 500 and 240 microM, respectively. SDS-PAGE demonstrated that ozone caused formation of high molecular weight aggregates in catalase and dimerization in glutathione peroxidase. Glutathione protected catalase and glutathione peroxidase from ozone but the effective concentrations were much higher than that for Cu/Zn superoxide dismutase. Ascorbate was almost ineffective. The result suggests that, among the three antioxidant enzymes, Cu/Zn superoxide dismutase is a major target for ozone-induced inactivation and both glutathione and ascorbate are very effective in protecting the enzyme from ozone.

  1. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects Are Diminished in Adrenalectomized Rats.

    PubMed

    Miller, Desinia B; Snow, Samantha J; Schladweiler, Mette C; Richards, Judy E; Ghio, Andrew J; Ledbetter, Allen D; Kodavanti, Urmila P

    2016-04-01

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent bilateral adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1 ppm), 4 h/day for 1 or 2 days and responses assessed immediately postexposure. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to SHAM. Corticosterone tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (P = .15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX > DEMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not observed in DEMED and ADREX rats. We demonstrate that ozone-induced peripheral metabolic effects and lung injury/inflammation are mediated through adrenal-derived stress hormones likely via the activation of stress response pathway.

  2. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects Are Diminished in Adrenalectomized Rats

    PubMed Central

    Miller, Desinia B.; Snow, Samantha J.; Schladweiler, Mette C.; Richards, Judy E.; Ghio, Andrew J.; Ledbetter, Allen D.; Kodavanti, Urmila P.

    2016-01-01

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent bilateral adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1 ppm), 4 h/day for 1 or 2 days and responses assessed immediately postexposure. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to SHAM. Corticosterone tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (P = .15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX > DEMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not observed in DEMED and ADREX rats. We demonstrate that ozone-induced peripheral metabolic effects and lung injury/inflammation are mediated through adrenal-derived stress hormones likely via the activation of stress response pathway. PMID:26732886

  3. Adrenal-derived stress hormones modulate ozone-induced lung injury and inflammation.

    PubMed

    Henriquez, Andres; House, John; Miller, Desinia B; Snow, Samantha J; Fisher, Anna; Ren, Hongzu; Schladweiler, Mette C; Ledbetter, Allen D; Wright, Fred; Kodavanti, Urmila P

    2017-08-15

    Ozone-induced systemic effects are modulated through activation of the neuro-hormonal stress response pathway. Adrenal demedullation (DEMED) or bilateral total adrenalectomy (ADREX) inhibits systemic and pulmonary effects of acute ozone exposure. To understand the influence of adrenal-derived stress hormones in mediating ozone-induced lung injury/inflammation, we assessed global gene expression (mRNA sequencing) and selected proteins in lung tissues from male Wistar-Kyoto rats that underwent DEMED, ADREX, or sham surgery (SHAM) prior to their exposure to air or ozone (1ppm), 4h/day for 1 or 2days. Ozone exposure significantly changed the expression of over 2300 genes in lungs of SHAM rats, and these changes were markedly reduced in DEMED and ADREX rats. SHAM surgery but not DEMED or ADREX resulted in activation of multiple ozone-responsive pathways, including glucocorticoid, acute phase response, NRF2, and PI3K-AKT. Predicted targets from sequencing data showed a similarity between transcriptional changes induced by ozone and adrenergic and steroidal modulation of effects in SHAM but not ADREX rats. Ozone-induced increases in lung Il6 in SHAM rats coincided with neutrophilic inflammation, but were diminished in DEMED and ADREX rats. Although ozone exposure in SHAM rats did not significantly alter mRNA expression of Ifnγ and Il-4, the IL-4 protein and ratio of IL-4 to IFNγ (IL-4/IFNγ) proteins increased suggesting a tendency for a Th2 response. This did not occur in ADREX and DEMED rats. We demonstrate that ozone-induced lung injury and neutrophilic inflammation require the presence of circulating epinephrine and corticosterone, which transcriptionally regulates signaling mechanisms involved in this response. Published by Elsevier Inc.

  4. Hydrogen Sulfide Prevents and Partially Reverses Ozone-Induced Features of Lung Inflammation and Emphysema in Mice.

    PubMed

    Li, Feng; Zhang, Pengyu; Zhang, Min; Liang, Li; Sun, Xiaoyuan; Li, Min; Tang, Yueqin; Bao, Aihua; Gong, Jicheng; Zhang, Junfeng; Adcock, Ian; Chung, Kian Fan; Zhou, Xin

    2016-07-01

    Hydrogen sulfide (H2S), a novel signaling gasotransmitter in the respiratory system, may have antiinflammatory properties in the lung. We examined the preventive and therapeutic effects of H2S on ozone-induced features of lung inflammation and emphysema. C57/BL6 mice were exposed to ozone or filtered air over 6 weeks. Sodium hydrogen sulfide (NaHS), an H2S donor, was administered to the mice either before ozone exposure (preventive effect) or after completion of 6 weeks of ozone exposure (therapeutic effect). The ozone-exposed mice developed emphysema, measured by micro-computed tomography and histology, airflow limitation, measured by the forced maneuver system, and increased lung inflammation with augmented IL-1β, IL-18, and matrix metalloproteinase-9 (MMP-9) gene expression. Ozone-induced changes were associated with increased Nod-like receptor pyrin domain containing 3 (NLRP3)-caspase-1 activation and p38 mitogen-activated protein kinase phosphorylation and decreased Akt phosphorylation. NaHS both prevented and reversed lung inflammation and emphysematous changes in alveolar space. In contrast, NaHS prevented, but did not reverse, ozone-induced airflow limitation and bronchial structural remodeling. In conclusion, NaHS administration prevented and partially reversed ozone-induced features of lung inflammation and emphysema via regulation of the NLRP3-caspase-1, p38 mitogen-activated protein kinase, and Akt pathways.

  5. Ozone-induced ethylene release from leaf surfaces

    SciTech Connect

    Rodecap, K.D.; Tingey, D.T.

    1986-01-01

    Ozone-induced stress-ethylene emissions from the adaxial and abaxial leaf surfaces of four plant species (Glycine max (L) Merr. cv. Dare, Lycopersicon esculentum Mill cv. Roma VF, Eucalyptus globulus Labill. and Hedera helix L.) were studied to determine if the stress ethylene diffused through the stomata or cuticle. In plants not exposed to ozone, basal ethylene was detected above both the adaxial and abaxial leaf surfaces of all the plant species examined, indicating that some ethylene can diffuse across the leaf cuticle. Oxone-induced stress ethylene production in all species examined. These data indicate that ozone-induced stress ethylene primarily diffuses from the leaf via the stomata.

  6. Classical and alternative macrophage activation in the lung following ozone-induced oxidative stress

    SciTech Connect

    Sunil, Vasanthi R.; Patel-Vayas, Kinal; Shen, Jianliang; Laskin, Jeffrey D.; Laskin, Debra L.

    2012-09-01

    Ozone is a pulmonary irritant known to cause oxidative stress, inflammation and tissue injury. Evidence suggests that macrophages play a role in the pathogenic response; however, their contribution depends on the mediators they encounter in the lung which dictate their function. In these studies we analyzed the effects of ozone-induced oxidative stress on the phenotype of alveolar macrophages (AM). Exposure of rats to ozone (2 ppm, 3 h) resulted in increased expression of 8-hydroxy-2′-deoxyguanosine (8-OHdG), as well as heme oxygenase-1 (HO-1) in AM. Whereas 8-OHdG was maximum at 24 h, expression of HO-1 was biphasic increasing after 3 h and 48–72 h. Cleaved caspase-9 and beclin-1, markers of apoptosis and autophagy, were also induced in AM 24 h post-ozone. This was associated with increased bronchoalveolar lavage protein and cells, as well as matrix metalloproteinase (MMP)-2 and MMP-9, demonstrating alveolar epithelial injury. Ozone intoxication resulted in biphasic activation of the transcription factor, NFκB. This correlated with expression of monocyte chemotactic protein‐1, inducible nitric oxide synthase and cyclooxygenase‐2, markers of proinflammatory macrophages. Increases in arginase-1, Ym1 and galectin-3 positive anti-inflammatory/wound repair macrophages were also observed in the lung after ozone inhalation, beginning at 24 h (arginase-1, Ym1), and persisting for 72 h (galectin-3). This was associated with increased expression of pro-surfactant protein-C, a marker of Type II cell proliferation and activation, important steps in wound repair. These data suggest that both proinflammatory/cytotoxic and anti-inflammatory/wound repair macrophages are activated early in the response to ozone-induced oxidative stress and tissue injury. -- Highlights: ► Lung macrophages are highly sensitive to ozone induced oxidative stress. ► Ozone induces autophagy and apoptosis in lung macrophages. ► Proinflammatory and wound repair macrophages are activated

  7. Bile acids: regulation of synthesis.

    PubMed

    Chiang, John Y L

    2009-10-01

    Bile acids are physiological detergents that generate bile flow and facilitate intestinal absorption and transport of lipids, nutrients, and vitamins. Bile acids also are signaling molecules and inflammatory agents that rapidly activate nuclear receptors and cell signaling pathways that regulate lipid, glucose, and energy metabolism. The enterohepatic circulation of bile acids exerts important physiological functions not only in feedback inhibition of bile acid synthesis but also in control of whole-body lipid homeostasis. In the liver, bile acids activate a nuclear receptor, farnesoid X receptor (FXR), that induces an atypical nuclear receptor small heterodimer partner, which subsequently inhibits nuclear receptors, liver-related homolog-1, and hepatocyte nuclear factor 4alpha and results in inhibiting transcription of the critical regulatory gene in bile acid synthesis, cholesterol 7alpha-hydroxylase (CYP7A1). In the intestine, FXR induces an intestinal hormone, fibroblast growth factor 15 (FGF15; or FGF19 in human), which activates hepatic FGF receptor 4 (FGFR4) signaling to inhibit bile acid synthesis. However, the mechanism by which FXR/FGF19/FGFR4 signaling inhibits CYP7A1 remains unknown. Bile acids are able to induce FGF19 in human hepatocytes, and the FGF19 autocrine pathway may exist in the human livers. Bile acids and bile acid receptors are therapeutic targets for development of drugs for treatment of cholestatic liver diseases, fatty liver diseases, diabetes, obesity, and metabolic syndrome.

  8. Adrenal-derived stress hormones modulate ozone-induced ...

    EPA Pesticide Factsheets

    Ozone-induced systemic effects are modulated through activation of the neuro-hormonal stress response pathway. Adrenal demedullation (DEMED)or bilateral total adrenalectomy (ADREX) inhibits systemic and pulmonary effect of acute ozone exposure. To understand the influence of adrenal-derived stress hormones in mediating ozone-induced lung injury/inflammation, we assessed global gene expression (mRNA sequencing) and selected proteins in lung tissues from male Wistar-Kyoto rats that underwent DEMED, ADREX, or sham surgery (SHAM)prior to their exposure to air or ozone (1 ppm),4 h/day for 1 or 2days. Ozone exposure significantly changed the expression of over 2300 genes in lungs of SHAM rats, and these changes were markedly reduced in DEMED and ADREX rats. SHAM surgery but not DEMED or ADREX resulted in activation of multiple ozone-responsive pathways, including glucocorticoid, acute phase response, NRF2, and Pl3K-AKT.Predicted targets from sequencing data showed a similarity between transcriptional changes induced by ozone and adrenergic and steroidal modulation of effects in SHAM but not ADREX rats. Ozone-induced Increases in lung 116 in SHAM rats coincided with neutrophilic Inflammation, but were diminished in DEMED and ADREX rats. Although ozone exposure in SHAM rats did not significantly alter mRNA expression of lfny and 11-4, the IL-4 protein and ratio of IL-4 to IFNy (IL-4/IFNy) proteins increased suggesting a tendency for a Th2 response. This did not occur

  9. Ozone-induced IL-17A and neutrophilic airway inflammation is orchestrated by the caspase-1-IL-1 cascade.

    PubMed

    Che, Luanqing; Jin, Yan; Zhang, Chao; Lai, Tianwen; Zhou, Hongbin; Xia, Lixia; Tian, Baoping; Zhao, Yun; Liu, Juan; Wu, Yinfang; Wu, Yanping; Du, Jie; Li, Wen; Ying, Songmin; Chen, Zhihua; Shen, Huahao

    2016-01-07

    Ozone is a common environmental air pollutant leading to respiratory illness. The mechanisms regulating ozone-induced airway inflammation remain poorly understood. We hypothesize that ozone-triggered inflammasome activation and interleukin (IL)-1 production regulate neutrophilic airway inflammation through IL-17A. Pulmonary neutrophilic inflammation was induced by extended (72 h) low-dose (0.7 ppm) exposure to ozone. IL-1 receptor 1 (Il1r1)(-/-), Il17a(-/-) mice and the caspase-1 inhibitor acetyl-YVAD-chloromethylketone (Ac-YVAD-cmk) were used for in vivo studies. Cellular inflammation and protein levels in bronchial alveolar lavage fluid (BALF), cytokines, and IL-17A-producing γδT-cells, as well as mitochondrial reactive oxygen species (ROS), mitochondrial DNA (mtDNA) release, and inflammasome activation in lung macrophages were analyzed. Ozone-induced neutrophilic airway inflammation, accompanied an increased production of IL-1β, IL-18, IL-17A, Granulocyte-colony stimulating factor (G-CSF), Interferon-γ inducible protein 10 (IP-10) and BALF protein in the lung. Ozone-induced IL-17A production was predominantly in γδT-cells, and Il17a-knockout mice exhibited reduced airway inflammation. Lung macrophages from ozone-exposed mice exhibited higher levels of mitochondrial ROS, enhanced cytosolic mtDNA, increased caspase-1 activation, and higher production of IL-1β. Il1r1-knockout mice or treatment with Ac-YVAD-cmk decreased the IL-17A production and subsequent airway inflammation. Taken together, we demonstrate that ozone-induced IL-17A and neutrophilic airway inflammation is orchestrated by the caspase-1-IL-1 cascade.

  10. Ozone-induced IL-17A and neutrophilic airway inflammation is orchestrated by the caspase-1-IL-1 cascade

    PubMed Central

    Che, Luanqing; Jin, Yan; Zhang, Chao; Lai, Tianwen; Zhou, Hongbin; Xia, Lixia; Tian, Baoping; Zhao, Yun; Liu, Juan; Wu, Yinfang; Wu, Yanping; Du, Jie; Li, Wen; Ying, Songmin; Chen, Zhihua; Shen, Huahao

    2016-01-01

    Ozone is a common environmental air pollutant leading to respiratory illness. The mechanisms regulating ozone-induced airway inflammation remain poorly understood. We hypothesize that ozone-triggered inflammasome activation and interleukin (IL)-1 production regulate neutrophilic airway inflammation through IL-17A. Pulmonary neutrophilic inflammation was induced by extended (72 h) low-dose (0.7 ppm) exposure to ozone. IL-1 receptor 1 (Il1r1)−/−, Il17a−/− mice and the caspase-1 inhibitor acetyl-YVAD-chloromethylketone (Ac-YVAD-cmk) were used for in vivo studies. Cellular inflammation and protein levels in bronchial alveolar lavage fluid (BALF), cytokines, and IL-17A-producing γδT-cells, as well as mitochondrial reactive oxygen species (ROS), mitochondrial DNA (mtDNA) release, and inflammasome activation in lung macrophages were analyzed. Ozone-induced neutrophilic airway inflammation, accompanied an increased production of IL-1β, IL-18, IL-17A, Granulocyte-colony stimulating factor (G-CSF), Interferon-γ inducible protein 10 (IP-10) and BALF protein in the lung. Ozone-induced IL-17A production was predominantly in γδT-cells, and Il17a-knockout mice exhibited reduced airway inflammation. Lung macrophages from ozone-exposed mice exhibited higher levels of mitochondrial ROS, enhanced cytosolic mtDNA, increased caspase-1 activation, and higher production of IL-1β. Il1r1-knockout mice or treatment with Ac-YVAD-cmk decreased the IL-17A production and subsequent airway inflammation. Taken together, we demonstrate that ozone-induced IL-17A and neutrophilic airway inflammation is orchestrated by the caspase-1-IL-1 cascade. PMID:26739627

  11. Amino acids and cell regulation.

    PubMed Central

    Forster, R. P.; Goldstein, L.

    1979-01-01

    Free amino play an important role in regulating cell volume in fishes. Four tissues/cells (skeletal muscle, RBC, brain, and myocardium) of the little skate, Raja erinacea, were selected for detailed study because of their special importance or unique advantage as experimental models. Three particular amino acids, beta-alanine, taurine, and sarcosine play a predominant role in all four tissues. As in higher vertebrates, amino acid uptake in skate brain, heart, and RBC is mediated via a Na+-dependent process. Amino acids leave the skate brain rapidly in response to a sudden decrease in plasma osmolality and/or to a simultaneous drop in extracellular Na+ concentration. However, although amino acids are important for volume regulation in normal brain cells, they do not appear to be likely candidates for the unidentified "idiogenic" osmolytes in mammalian brain cells. The high concentration of taurine in skate myocardium is of special interest because of the special role of this amino acid in myocardial contractility. Thus, unlike beta-alanine and sarcosine, taurine may play a dual role in regulating both cell volume and contractility of myocardial cells. The isolated skate atrium is well suited for in vitro studies of these two processes. PMID:395764

  12. Ozone-induced augmentation of eicosanoid metabolism in epithelial cells from bovine trachea.

    PubMed

    Leikauf, G D; Driscoll, K E; Wey, H E

    1988-02-01

    Epithelial injury and inflammation have been implicated in ozone-induced airway hyperresponsiveness. Because ozone is relatively insoluble and highly reactive, toxicologic effects of this compound may be limited to the plasma membranes of airway epithelium. We hypothesize that oxidant damage to epithelium may result in elaboration of various eicosanoids, which are known to alter airway smooth muscle responsiveness and epithelial cell functions (including ion transport). To examine eicosanoid metabolism after exposure to 0.1 to 10.0 ppm ozone, epithelial cells derived from bovine trachea were isolated and grown to confluency. Bovine tracheal cells in culture expressed differentiated features characteristic of epithelial cells, including a plasma membrane with a specialized polar morphology, an extensive network of filaments that were connected through intercellular junctional complexes, and keratin-containing monofilaments as determined by indirect immunofluorescent localization. Monolayers were alternately exposed to ozone and culture medium for 2 h in a specially designed in vitro chamber using a rotating inclined platform. Eicosanoid products were measured by the release of [3H]-labeled products from cells incubated with [3H]-arachidonic acid for 24 h before exposure and by the release of immunoreactive products into the cell supernatant. Both methods revealed ozone-induced increases in cyclooxygenase and lipoxygenase product formation with significant increases in prostaglandins E2, F2 alpha, 6-keto F1 alpha, and leukotriene B4. Release rates of immunoreactive products were dose-dependent, and ozone concentrations as low as 0.1 ppm produced an increase in prostaglandin F2 alpha. These findings are consistent with the hypothesis that ozone can augment eicosanoid metabolism in airway epithelial cells.

  13. Virucidal levels of ozone induce hemolysis and hemoglobin degradation

    SciTech Connect

    Wagner, S.J.; Wagner, K.F.; Friedman, L.I.; Benade, L.F. )

    1991-10-01

    The animal virus, vesicular stomatitis virus (VSV), and the bacterial virus, phi 6, were inactivated by greater than 4 log10 in response to incubation with 13 to 14 mL of 1.4 mmol per L (65 micrograms/mL) to 1.6 mmol per L (75 micrograms/mL) of overlaid ozone in virus-spiked, dilute, red cell suspensions. Virus inactivation was greatly inhibited when ozone was overlaid in the presence of high-hematocrit red cells or, to a lesser degree, high levels of plasma. At hematocrits at which 5 to 6 log10 of VSV were inactivated, ozone caused 30-percent hemolysis, as measured by the loss of total cellular hemoglobin. Unexpectedly, this level of hemolysis could not be observed in supernatants because of the ozone-induced destruction (bleaching) of extracellular hemoglobin. These results suggest that ozone may have little biological specificity for damaging viruses over red cells.

  14. Lung transcriptional profiling: insights into the mechanisms of ozone-induced pulmonary injury in Wistar Kyoto rats.

    PubMed

    Ward, William O; Ledbetter, Allen D; Schladweiler, Mette C; Kodavanti, Urmila P

    2015-01-01

    Acute ozone-induced pulmonary injury and inflammation are well characterized in rats; however, mechanistic understanding of the pathways involved is limited. We hypothesized that acute exposure of healthy rats to ozone will cause transcriptional alterations, and comprehensive analysis of these changes will allow us to better understand the mechanism of pulmonary injury and inflammation. Male Wistar Kyoto rats (10-12 week) were exposed to air, or ozone (0.25, 0.5 or 1.0 ppm) for 4 h and pulmonary injury and inflammation were assessed at 0-h or 20-h (n = 8/group). Lung gene expression profiling was assessed at 0-h (air and 1.0 ppm ozone, n = 3-4/group). At 20-h bronchoalveolar lavage, fluid protein and neutrophils increased at 1 ppm ozone. Numerous genes involved in acute inflammatory response were up-regulated along with changes in genes involved in cell adhesion and migration, steroid metabolism, apoptosis, cell cycle control and cell growth. A number of NRF2 target genes were also induced after ozone exposure. Based on expression changes, Rela, SP1 and TP3-mediated signaling were identified to be mediating downstream changes. Remarkable changes in the processes of endocytosis provide the insight that ozone-induced lung injury and inflammation are likely initiated by changes in cell membrane components and receptors likely from oxidatively modified lung lining lipids and proteins. In conclusion, ozone-induced injury and inflammation are preceded by changes in gene targets for cell adhesion/migration, apoptosis, cell cycle control and growth regulated by Rela, SP1 and TP53, likely mediated by the process of endocytosis and altered steroid receptor signaling.

  15. Newly divided eosinophils limit ozone-induced airway hyperreactivity in nonsensitized guinea pigs.

    PubMed

    Wicher, Sarah A; Jacoby, David B; Fryer, Allison D

    2017-06-01

    Ozone causes vagally mediated airway hyperreactivity and recruits inflammatory cells, including eosinophils, to lungs, where they mediate ozone-induced hyperreactivity 1 day after exposure but are paradoxically protective 3 days later. We aimed to test the role of newly divided eosinophils in ozone-induced airway hyperreactivity in sensitized and nonsensitized guinea pigs. Nonsensitized and sensitized guinea pigs were treated with 5-bromo-2-deoxyuridine (BrdU) to label newly divided cells and were exposed to air or ozone for 4 h. Later (1 or 3 days later), vagally induced bronchoconstriction was measured, and inflammatory cells were harvested from bone marrow, blood, and bronchoalveolar lavage. Ozone induced eosinophil hematopoiesis. One day after ozone, mature eosinophils dominate the inflammatory response and potentiate vagally induced bronchoconstriction. However, by 3 days, newly divided eosinophils have reached the lungs, where they inhibit ozone-induced airway hyperreactivity because depleting them with antibody to IL-5 or a TNF-α antagonist worsened vagally induced bronchoconstriction. In sensitized guinea pigs, both ozone-induced eosinophil hematopoiesis and subsequent recruitment of newly divided eosinophils to lungs 3 days later failed to occur. Thus mature eosinophils dominated the ozone-induced inflammatory response in sensitized guinea pigs. Depleting these mature eosinophils prevented ozone-induced airway hyperreactivity in sensitized animals. Ozone induces eosinophil hematopoiesis and recruitment to lungs, where 3 days later, newly divided eosinophils attenuate vagally mediated hyperreactivity. Ozone-induced hematopoiesis of beneficial eosinophils is blocked by a TNF-α antagonist or by prior sensitization. In these animals, mature eosinophils are associated with hyperreactivity. Thus interventions targeting eosinophils, although beneficial in atopic individuals, may delay resolution of airway hyperreactivity in nonatopic individuals. Copyright

  16. THE RELATIONSHIP BETWEEN OZONE-INDUCED LUNG INJURY, ANTIOXIDANT COMPENSATION AND UNDERLYING CARDIOVASCULAR DISEASE (CVD).

    EPA Science Inventory

    Increased levels of oxidants and compromised compensatory response are associated with CVD susceptibility. We hypothesized that rat strains demonstrating genetic CVD will have lower levels of antioxidants and greater ozone-induced pulmonary injury relative to healthy strains. Mal...

  17. THE RELATIONSHIP BETWEEN OZONE-INDUCED LUNG INJURY, ANTIOXIDANT COMPENSATION AND UNDERLYING CARDIOVASCULAR DISEASE (CVD).

    EPA Science Inventory

    Increased levels of oxidants and compromised compensatory response are associated with CVD susceptibility. We hypothesized that rat strains demonstrating genetic CVD will have lower levels of antioxidants and greater ozone-induced pulmonary injury relative to healthy strains. Mal...

  18. The Kidney and Acid-Base Regulation

    ERIC Educational Resources Information Center

    Koeppen, Bruce M.

    2009-01-01

    Since the topic of the role of the kidneys in the regulation of acid base balance was last reviewed from a teaching perspective (Koeppen BM. Renal regulation of acid-base balance. Adv Physiol Educ 20: 132-141, 1998), our understanding of the specific membrane transporters involved in H+, HCO , and NH transport, and especially how these…

  19. The Kidney and Acid-Base Regulation

    ERIC Educational Resources Information Center

    Koeppen, Bruce M.

    2009-01-01

    Since the topic of the role of the kidneys in the regulation of acid base balance was last reviewed from a teaching perspective (Koeppen BM. Renal regulation of acid-base balance. Adv Physiol Educ 20: 132-141, 1998), our understanding of the specific membrane transporters involved in H+, HCO , and NH transport, and especially how these…

  20. Role of neutrophilic inflammation in ozone-induced epithelial alterations in the nasal airways of rats

    NASA Astrophysics Data System (ADS)

    Cho, Hye Youn

    Ozone is a principal oxidant air pollutant in photochemical smog. Epithelial cells lining the centriacinar region of lung and the proximal aspects of nasal passage are primary target sites for ozone-induced injury in laboratory animals. Acute exposure of rats to high ambient concentrations of ozone (e.g., 0.5 ppm) results in neutrophilic inflammation, epithelial hyperplasia and mucous cell metaplasia (MCM) in the nasal transitional epithelium (NTE) lining the proximal nasal airways. The principal purpose of the present study was to investigate the role of pre-metaplastic cellular responses, especially neutrophilic inflammation, in the pathogenesis of ozone-induced MCM in rat NTE. For this purpose, three specific hypotheses-based whole-animal inhalation studies were conducted. Male F344/N rats were exposed in whole-body inhalation chambers to 0 (filtered air) or 0.5 ppm ozone for 1-3 days (8 h/day). Histochemical, immunochemical, molecular and morphometric techniques were used to investigate the ozone-induced cellular and molecular events in the NTE. Two in vitro studies were also conducted to examine the effects of ozone-inducible cytokines (i.e., tumor necrosis factor-alpha; TNF- a, and interleukin-6; IL-6) on mucin gene (rMuc-5AC) expression. Ozone induced a rapid increase of rMuc-5AC mRNA in nasal tissues within hours after the start of exposure. It preceded the appearance of MCM, and persisted with MCM. Ozone-induced neutrophilic inflammation accompanied the mucin gene upregulation, but was resolved when MCM first appeared in the NTE. Antibody-mediated depletion of circulating neutrophils attenuated ozone-induced MCM, although it did not affect the ozone-induced epithelial hyperplasia and mucin mRNA upregulation. In another study, it was found that preexisting neutrophilic rhinitis induced by endotoxin augmented the ozone-induced MCM. However, pre-existing rhinitis did not alter the severity of ozone-induced epithelial hyperplasia and mucin gene upregulation

  1. Executive Summary: variation in susceptibility to ozone-induced health effects in rodent models of cardiometabolic disease.

    PubMed

    Dye, Janice A; Costa, Daniel L; Kodavanti, Urmila P

    2015-01-01

    Seven million premature deaths occur annually due to air pollution worldwide, of which ∼80% are attributed to exacerbation of cardiovascular disease (CVD), necessitating greater attention to understanding the causes of susceptibility to air pollution in this sector of population. We used rat models of CVD with or without obesity and compared them to healthy strains to examine the risk factors of ozone-induced lung injury and inflammation. We examined functional, biochemical and molecular changes in several organs to evaluate how physiological factors as well as compensatory antioxidant reserves modulate processes by which ozone injury is influenced by underlying disease. In this study, we highlight key findings of this series of reports. We show that underlying cardiopulmonary insufficiency in genetically predisposed rats appears to increase the effective ozone dose; thus dosimetry is one factor contributing to exacerbated ozone effects. We further show that antioxidant reserve in airway lining fluid modulates ozone-induced damage such that strains with the least antioxidant reserve incur the greatest injury. And finally, we show that the inflammatory response to ozone is governed by a cluster of genes involved in regulating cytokine release, trafficking of inflammatory cells and processes related to cellular apoptosis and growth. All such processes are influenced not only by ozone dosimetry and the lung antioxidant milieu but also by the strain-specific genetic factors. In using a comprehensive systems biology research approach, our data reveal key risk factors for--and strategies to reduce risk of--air pollution mortality among those with CVD.

  2. Ozone-induced injury and oxidative stress in bronchiolar epithelium are associated with altered pulmonary mechanics.

    PubMed

    Sunil, Vasanthi R; Vayas, Kinal N; Massa, Christopher B; Gow, Andrew J; Laskin, Jeffrey D; Laskin, Debra L

    2013-06-01

    In these studies, we analyzed the effects of ozone on bronchiolar epithelium. Exposure of rats to ozone (2 ppm, 3 h) resulted in rapid (within 3 h) and persistent (up to 72 h) histological changes in the bronchiolar epithelium, including hypercellularity, loss of cilia, and necrotizing bronchiolitis. Perivascular edema and vascular congestion were also evident, along with a decrease in Clara cell secretory protein in bronchoalveolar lavage, which was maximal 24 h post-exposure. Ozone also induced the appearance of 8-hydroxy-2'-deoxyguanosine, Ym1, and heme oxygenase-1 in the bronchiolar epithelium. This was associated with increased expression of cleaved caspase-9 and beclin-1, indicating initiation of apoptosis and autophagy. A rapid and persistent increase in galectin-3, a regulator of epithelial cell apoptosis, was also observed. Following ozone exposure (3-24 h), increased expression of cyclooxygenase-2, inducible nitric oxide synthase, and arginase-1 was noted in bronchiolar epithelium. Ozone-induced injury and oxidative stress in bronchiolar epithelium were linked to methacholine-induced alterations in pulmonary mechanics. Thus, significant increases in lung resistance and elastance, along with decreases in lung compliance and end tidal volume, were observed at higher doses of methacholine. This indicates that ozone causes an increase in effective stiffness of the lung as a consequence of changes in the conducting airways. Collectively, these studies demonstrate that bronchiolar epithelium is highly susceptible to injury and oxidative stress induced by acute exposure to ozone; moreover, this is accompanied by altered lung functioning.

  3. Ozone-Induced Injury and Oxidative Stress in Bronchiolar Epithelium Are Associated with Altered Pulmonary Mechanics

    PubMed Central

    Sunil, Vasanthi R.

    2013-01-01

    In these studies, we analyzed the effects of ozone on bronchiolar epithelium. Exposure of rats to ozone (2 ppm, 3h) resulted in rapid (within 3h) and persistent (up to 72h) histological changes in the bronchiolar epithelium, including hypercellularity, loss of cilia, and necrotizing bronchiolitis. Perivascular edema and vascular congestion were also evident, along with a decrease in Clara cell secretory protein in bronchoalveolar lavage, which was maximal 24h post-exposure. Ozone also induced the appearance of 8-hydroxy-2′-deoxyguanosine, Ym1, and heme oxygenase-1 in the bronchiolar epithelium. This was associated with increased expression of cleaved caspase-9 and beclin-1, indicating initiation of apoptosis and autophagy. A rapid and persistent increase in galectin-3, a regulator of epithelial cell apoptosis, was also observed. Following ozone exposure (3–24h), increased expression of cyclooxygenase-2, inducible nitric oxide synthase, and arginase-1 was noted in bronchiolar epithelium. Ozone-induced injury and oxidative stress in bronchiolar epithelium were linked to methacholine-induced alterations in pulmonary mechanics. Thus, significant increases in lung resistance and elastance, along with decreases in lung compliance and end tidal volume, were observed at higher doses of methacholine. This indicates that ozone causes an increase in effective stiffness of the lung as a consequence of changes in the conducting airways. Collectively, these studies demonstrate that bronchiolar epithelium is highly susceptible to injury and oxidative stress induced by acute exposure to ozone; moreover, this is accompanied by altered lung functioning. PMID:23492811

  4. Ethylene insensitivity modulates ozone-induced cell death in birch.

    PubMed

    Vahala, Jorma; Ruonala, Raili; Keinänen, Markku; Tuominen, Hannele; Kangasjärvi, Jaakko

    2003-05-01

    We have used genotypic variation in birch (Betula pendula Roth) to investigate the roles of ozone (O(3))-induced ethylene (ET), jasmonic acid, and salicylic acid in the regulation of tissue tolerance to O(3). Of these hormones, ET evolution correlated best with O(3)-induced cell death. Disruption of ET perception by transformation of birch with the dominant negative mutant allele etr1-1 of the Arabidopsis ET receptor gene ETR1 or blocking of ET perception with 1-methylcyclopropene reduced but did not completely prevent the O(3)-induced cell death, when inhibition of ET biosynthesis with aminooxyacetic acid completely abolished O(3) lesion formation. This suggests the presence of an ET-signaling-independent but ET biosynthesis-dependent component in the ET-mediated stimulation of cell death in O(3)-exposed birch. Functional ET signaling was required for the O(3) induction of the gene encoding beta-cyanoalanine synthase, which catalyzes detoxification of the cyanide formed during ET biosynthesis. The results suggest that functional ET signaling is required to protect birch from the O(3)-induced cell death and that a decrease in ET sensitivity together with a simultaneous, high ET biosynthesis can potentially cause cell death through a deficient detoxification of cyanide.

  5. Amino acid regulation of gene expression.

    PubMed Central

    Fafournoux, P; Bruhat, A; Jousse, C

    2000-01-01

    The impact of nutrients on gene expression in mammals has become an important area of research. Nevertheless, the current understanding of the amino acid-dependent control of gene expression is limited. Because amino acids have multiple and important functions, their homoeostasis has to be finely maintained. However, amino-acidaemia can be affected by certain nutritional conditions or various forms of stress. It follows that mammals have to adjust several of their physiological functions involved in the adaptation to amino acid availability by regulating the expression of numerous genes. The aim of the present review is to examine the role of amino acids in regulating mammalian gene expression and protein turnover. It has been reported that some genes involved in the control of growth or amino acid metabolism are regulated by amino acid availability. For instance, limitation of several amino acids greatly increases the expression of the genes encoding insulin-like growth factor binding protein-1, CHOP (C/EBP homologous protein, where C/EBP is CCAAT/enhancer binding protein) and asparagine synthetase. Elevated mRNA levels result from both an increase in the rate of transcription and an increase in mRNA stability. Several observations suggest that the amino acid regulation of gene expression observed in mammalian cells and the general control process described in yeast share common features. Moreover, amino acid response elements have been characterized in the promoters of the CHOP and asparagine synthetase genes. Taken together, the results discussed in the present review demonstrate that amino acids, by themselves, can, in concert with hormones, play an important role in the control of gene expression. PMID:10998343

  6. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    PubMed Central

    Lee, Je Min; Lee, Hyungjae; Kang, SeokBeom; Park, Woo Jung

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism. PMID:26742061

  7. Ozone-induced dissociation: elucidation of double bond position within mass-selected lipid ions.

    PubMed

    Thomas, Michael C; Mitchell, Todd W; Harman, David G; Deeley, Jane M; Nealon, Jessica R; Blanksby, Stephen J

    2008-01-01

    Ions formed from lipids during electrospray ionization of crude lipid extracts have been mass-selected within a quadrupole linear ion trap mass spectrometer and allowed to react with ozone vapor. Gas-phase ion-molecule reactions between unsaturated lipid ions and ozone are found to yield two primary product ions for each carbon-carbon double bond within the molecule. The mass-to-charge ratios of these chemically induced fragments are diagnostic of the position of unsaturation within the precursor ion. This novel analytical technique, dubbed ozone-induced dissociation (OzID), can be applied both in series and in parallel with conventional collision-induced dissociation (CID) to provide near-complete structural assignment of unknown lipids within complex mixtures without prior fractionation or derivatization. In this study, OzID is applied to a suite of complex lipid extracts from sources including human lens, bovine kidney, and commercial olive oil, thus demonstrating the technique to be applicable to a broad range of lipid classes including both neutral and acidic glycerophospholipids, sphingomyelins, and triacylglycerols. Gas-phase ozonolysis reactions are also observed with different types of precursor ions including [M+H]+, [M+Li]+, [M+Na]+, and [M-H]-: in each case yielding fragmentation data that allow double bond position to be unambiguously assigned. Within the human lens lipid extract, three sphingomyelin regioisomers, namely SM(d18:0/15Z-24:1), SM(d18:0/17Z-24:1), and SM(d18:0/19Z-24:1), and a novel phosphatidylethanolamine alkyl ether, GPEtn(11Z-18:1e/9Z-18:1), are identified using a combination of CID and OzID. These discoveries demonstrate that lipid identification based on CID alone belies the natural structural diversity in lipid biochemistry and illustrate the potential of OzID as a complementary approach within automated, high-throughput lipid analysis protocols.

  8. Bioinforrnatics of Gene Expression Profiling Data Provide Mechanistic Understanding of Acute Ozone-Induced Lung injury

    EPA Science Inventory

    Acute ozone-induced pulmonary injury and inflammation are well characterized. A few studies have used gene expression profiling to determine the types of changes induced by ozone; however the mechanisms or the pathways involved are less well understood. We presumed that robust bi...

  9. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests.

    PubMed

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-05-06

    Tropospheric ozone concentrations have increased by 60-100% in the Northern Hemisphere since the 19(th) century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected.

  10. OZONE-INDUCED RESPIRATORY SYMPTOMS: EXPOSURE-RESPONSE MODELS AND ASSOCIATION WITH LUNG FUNCTION

    EPA Science Inventory

    Ozone-induced respiratory symptoms are known to be functions of concentration, minute ventilation, and duration of exposure. The purposes of this study were to identify an exposure-response model for symptoms, to determine whether response was related to age, and to assess the re...

  11. OZONE-INDUCED RESPIRATORY SYMPTOMS: EXPOSURE-RESPONSE MODELS AND ASSOCIATION WITH LUNG FUNCTION

    EPA Science Inventory

    Ozone-induced respiratory symptoms are known to be functions of concentration, minute ventilation, and duration of exposure. The purposes of this study were to identify an exposure-response model for symptoms, to determine whether response was related to age, and to assess the re...

  12. Adrenal-derived stress hormones modulate ozone-induced lung injury and inflammation

    EPA Science Inventory

    Ozone-induced systemic effects are modulated through activation of the neuro-hormonal stress response pathway. Adrenal demedullation (DEMED)or bilateral total adrenalectomy (ADREX) inhibits systemic and pulmonary effect of acute ozone exposure. To understand the influence of adre...

  13. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects are Diminished in Adrenalectomized Rats

    EPA Science Inventory

    Acute ozone exposure increases circulating stress hormones and induces peripheral metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for ozone-induced systemic metabolic effects and lung injury. Male Wis...

  14. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects are Diminished in Adrenalectomized Rats#

    EPA Science Inventory

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats ...

  15. Stratospheric Ozone-induced Indirect Radiative Effects on Antarctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Xia, Y.; LIU, J.; Huang, Y.

    2015-12-01

    Recent studies demonstrated that the Antarctic Ozone Hole has important influences on Antarctic sea ice. While all these have focused on stratospheric ozone-induced dynamic effects on sea ice, here we show results that ozone-induced indirect radiative effects have important influences on Antarctic sea ice. Our simulations demonstrate that the recovery of the Antarctic Ozone Hole causes equatorward shift of clouds over the Southern Ocean. The cloud-band shift leads to reduction of downward infrared radiation, which causes surface cooling. On the other hand, it also causes increasing solar radiation on the surface. However, the increase in solar radiation is offset by surface reflection due to increasing sea ice. As a result solar radiation absorbed by the surface is reduced, which also causes surface cooling. Therefore, the overall ozone-induced cloud radiative effect is to cool the surface and causes expansion of sea ice around the Antarctic. As shown in previous studies, the cloud-band shift is associated with the equatorward shift of the westerly jet stream around the Antarctic. Our simulations also demonstrate increasing snow rate near the sea ice edge, which also contributes to Antarctic sea-ice expansion. The ozone-induced cloud radiative effect would mitigate Antarctic sea-ice melting due to greenhouse warming in the 21st century.

  16. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-05-01

    Tropospheric ozone concentrations have increased by 60-100% in the Northern Hemisphere since the 19th century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected.

  17. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects are Diminished in Adrenalectomized Rats#

    EPA Science Inventory

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats ...

  18. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects are Diminished in Adrenalectomized Rats

    EPA Science Inventory

    Acute ozone exposure increases circulating stress hormones and induces peripheral metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for ozone-induced systemic metabolic effects and lung injury. Male Wis...

  19. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests

    PubMed Central

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-01-01

    Tropospheric ozone concentrations have increased by 60–100% in the Northern Hemisphere since the 19th century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected. PMID:25943276

  20. Bioinforrnatics of Gene Expression Profiling Data Provide Mechanistic Understanding of Acute Ozone-Induced Lung injury

    EPA Science Inventory

    Acute ozone-induced pulmonary injury and inflammation are well characterized. A few studies have used gene expression profiling to determine the types of changes induced by ozone; however the mechanisms or the pathways involved are less well understood. We presumed that robust bi...

  1. A DYNAMIC NONLINEAR MODEL OF OZONE-INDUCED FEV1 RESPONSE UNDER CHANGING EXPOSURE CONDITIONS

    EPA Science Inventory

    A Dynamic Nonlinear Model of Ozone-induced FEV1 Response under Changing Exposure Conditions. 1WF McDonnell, 2PW Stewart, 3MV Smith. 1Human Studies Division, NHEERL, U.S. EPA, RTP, NC. 2University of North Carolina, Chapel Hill, NC. 3ASI, Durham, NC.

    Ozone exposure result...

  2. Climatic regulation of the neurotoxin domoic acid.

    PubMed

    McKibben, S Morgaine; Peterson, William; Wood, A Michelle; Trainer, Vera L; Hunter, Matthew; White, Angelicque E

    2017-01-10

    Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers and wildlife in coastal regions worldwide. Evidence of climatic regulation of domoic acid in shellfish over the past 20 y in the Northern California Current regime is shown. The timing of elevated domoic acid is strongly related to warm phases of the Pacific Decadal Oscillation and the Oceanic Niño Index, an indicator of El Niño events. Ocean conditions in the northeast Pacific that are associated with warm phases of these indices, including changes in prevailing currents and advection of anomalously warm water masses onto the continental shelf, are hypothesized to contribute to increases in this toxin. We present an applied domoic acid risk assessment model for the US West Coast based on combined climatic and local variables. Evidence of regional- to basin-scale controls on domoic acid has not previously been presented. Our findings have implications in coastal zones worldwide that are affected by this toxin and are particularly relevant given the increased frequency of anomalously warm ocean conditions.

  3. Climatic regulation of the neurotoxin domoic acid

    PubMed Central

    McKibben, S. Morgaine; Peterson, William; Wood, A. Michelle; Trainer, Vera L.; Hunter, Matthew; White, Angelicque E.

    2017-01-01

    Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers and wildlife in coastal regions worldwide. Evidence of climatic regulation of domoic acid in shellfish over the past 20 y in the Northern California Current regime is shown. The timing of elevated domoic acid is strongly related to warm phases of the Pacific Decadal Oscillation and the Oceanic Niño Index, an indicator of El Niño events. Ocean conditions in the northeast Pacific that are associated with warm phases of these indices, including changes in prevailing currents and advection of anomalously warm water masses onto the continental shelf, are hypothesized to contribute to increases in this toxin. We present an applied domoic acid risk assessment model for the US West Coast based on combined climatic and local variables. Evidence of regional- to basin-scale controls on domoic acid has not previously been presented. Our findings have implications in coastal zones worldwide that are affected by this toxin and are particularly relevant given the increased frequency of anomalously warm ocean conditions. PMID:28069959

  4. Climatic regulation of the neurotoxin domoic acid

    NASA Astrophysics Data System (ADS)

    Morgaine McKibben, S.; Peterson, William; Wood, A. Michelle; Trainer, Vera L.; Hunter, Matthew; White, Angelicque E.

    2017-01-01

    Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers and wildlife in coastal regions worldwide. Evidence of climatic regulation of domoic acid in shellfish over the past 20 y in the Northern California Current regime is shown. The timing of elevated domoic acid is strongly related to warm phases of the Pacific Decadal Oscillation and the Oceanic Niño Index, an indicator of El Niño events. Ocean conditions in the northeast Pacific that are associated with warm phases of these indices, including changes in prevailing currents and advection of anomalously warm water masses onto the continental shelf, are hypothesized to contribute to increases in this toxin. We present an applied domoic acid risk assessment model for the US West Coast based on combined climatic and local variables. Evidence of regional- to basin-scale controls on domoic acid has not previously been presented. Our findings have implications in coastal zones worldwide that are affected by this toxin and are particularly relevant given the increased frequency of anomalously warm ocean conditions.

  5. Lung transcriptional profiling: insights into the mechanisms of ozone-induced pulmonary injury in Wistar Kyoto rats

    EPA Science Inventory

    Acute ozone-induced pulmonary injury and inflammation are well characterized in rats; however, mechanistic understanding of the pathways involved is limited. We hypothesized that acute exposure of healthy rats to ozone will cause transcriptional alterations, and comprehensive ana...

  6. Stressed lungs: unveiling the role of circulating stress hormones in ozone-induced lung injury and inflammation.

    EPA Science Inventory

    Ozone, a major component of smog generated through the interaction of light and anthropogenic emissions, induces adverse pulmonary, cardiovascular, and systemic health effects upon inhalation. It is generally accepted that ozone-induced lung injury is mediated by its interaction ...

  7. Lung transcriptional profiling: insights into the mechanisms of ozone-induced pulmonary injury in Wistar Kyoto rats

    EPA Science Inventory

    Acute ozone-induced pulmonary injury and inflammation are well characterized in rats; however, mechanistic understanding of the pathways involved is limited. We hypothesized that acute exposure of healthy rats to ozone will cause transcriptional alterations, and comprehensive ana...

  8. Stressed lungs: unveiling the role of circulating stress hormones in ozone-induced lung injury and inflammation.

    EPA Science Inventory

    Ozone, a major component of smog generated through the interaction of light and anthropogenic emissions, induces adverse pulmonary, cardiovascular, and systemic health effects upon inhalation. It is generally accepted that ozone-induced lung injury is mediated by its interaction ...

  9. Gender differences in ozone-induced pulmonary and metabolic health effects

    EPA Science Inventory

    SOT 2015 abstractGender differences in ozone-induced pulmonary and metabolic health effectsU.P. Kodavanti1, V.L. Bass2, M.C. Schladweiler1, C.J. Gordon3, K.A. Jarema3, P. Phillips3, A.D. Ledbetter1, D.B. Miller4, S. Snow5, J.E. Richards1. 1 EPHD, NHEERL, USEPA, Research Triangle ...

  10. Involvement of superoxide in ozone-induced airway hyperresponsiveness in anesthetized cats

    SciTech Connect

    Takahashi, T.; Miura, M.; Katsumata, U.; Ichinose, M.; Kimura, K.; Inoue, H.; Takishima, T.; Shirato, K. )

    1993-07-01

    To determine whether oxygen radical scavengers inhibit ozone-induced airway hyperresponsiveness, we examined the protective effect of polyethylene glycol-superoxide dismutase (PEG-SOD) and PEG-catalase (PEG-CAT) on ozone-induced airway hyperresponsiveness in cat airways. Twenty-five cats divided into five groups were anesthetized and mechanically ventilated. There was no difference between the groups in baseline airway responsiveness to inhaled acetylcholine (ACh). In the control group, AChPC, the concentration required to produce a doubling increase in baseline pulmonary resistance, was significantly reduced by ozone exposure (2.0 ppm for 2 h); the ratios of AChPC before ozone exposure to after ozone exposure (AChPC ratio) were 14.8 +/- 5.7 (p < 0.001) and 4.80 +/- 1.6 (p < 0.01) 30 and 120 min after exposure, respectively. Local administration of PEG-SOD (2,000 U/kg) into airways partially but significantly prevented ozone-induced airway hyperresponsiveness. The AChPC ratios were 6.2 +/- 1.4 and 1.5 +/- 0.2 30 and 120 min after exposure, respectively, which were significantly different from those of the control group (p < 0.05), whereas PEG-CAT pretreatment (6,000 U/kg) was without effect. Combined pretreatment with PEG-SOD and PEG-CAT had no additional protective effect compared with PEG-SOD alone. PEG-SOD had no direct effect on airway responsiveness to ACh. These results suggest that superoxide may be involved in ozone-induced airway hyperresponsiveness.

  11. Indomethacin does not inhibit the ozone-induced increase in bronchial responsiveness in human subjects

    SciTech Connect

    Ying, R.L.; Gross, K.B.; Terzo, T.S.; Eschenbacher, W.L. )

    1990-10-01

    Exposure of human subjects to sufficiently high levels of ozone can result in reversible changes in lung function (restrictive in nature) and increases in nonspecific airway responsiveness. Several studies have implicated products of cyclooxygenase metabolism in the mediation of these changes. The purpose of this study was to determine if indomethacin (a cyclooxygenase inhibitor) would alter the changes in the ozone-induced increase in responsiveness to methacholine or the ozone-induced decrease in lung function. Thirteen male subjects underwent three randomly assigned 2-h exposure to 0.4 ppm ozone with alternating 15-min periods of rest and exercise on a cycle ergometer (30 L/min/m2, body surface area). For the 4 days before each of the exposures, the subjects received either indomethacin (150 mg/day) or placebo, or no modification. Of the 13 subjects, only seven had both detectable indomethacin serum levels on the indomethacin Study Day and a significant increase in bronchial responsiveness to methacholine on the No Medication Day. For this group of seven subjects, we found that indomethacin did not alter the ozone-induced increase in bronchial responsiveness to methacholine (decrease in PC100SRaw for the different study days: no medication, -78.4 +/- 5.3% (mean +/- SEM); placebo, -48.9 +/- 12.2%; indomethacin, -64.5 +/- 6.3%; p greater than 0.2), although indomethacin did attenuate the ozone-induced decrease in lung function. The decrease in the FEV1 for the different study days was as follows: no medication, -20.7 +/- 5.0% (mean +/- SEM); placebo, -19.2 +/- 6.3%; indomethacin, -4.8 +/- 3.7% (p less than 0.001).

  12. Gender differences in ozone-induced pulmonary and metabolic health effects

    EPA Science Inventory

    SOT 2015 abstractGender differences in ozone-induced pulmonary and metabolic health effectsU.P. Kodavanti1, V.L. Bass2, M.C. Schladweiler1, C.J. Gordon3, K.A. Jarema3, P. Phillips3, A.D. Ledbetter1, D.B. Miller4, S. Snow5, J.E. Richards1. 1 EPHD, NHEERL, USEPA, Research Triangle ...

  13. Ozone-induced changes in natural organic matter (NOM) structure

    USGS Publications Warehouse

    Westerhoff, P.; Debroux, J.; Aiken, G.; Amy, G.

    1999-01-01

    Hydrophobic organic acids (combined humic and fulvic acids), obtained from an Antarctic Lake with predominantly microbially derived organic carbon sources and two US fiver systems with terrestrial organic carbon sources, were ozonated. Several analyses, including 13C-NMR, UV absorbance, fluorescence, hydrophobic/transphilic classification, and potentiometric titrations, were performed before and after ozonation. Ozonation reduced aromatic carbon content, selectively reducing phenolic carbon content. Ozonation of the samples resulted in increased aliphatic, carboxyl, plus acetal and ketal anomeric carbon content and shifted towards less hydrophobic compounds.Hydrophobic organic acids (combined humic and fulvic acids), obtained from an Antarctic Lake with predominantly microbially derived organic carbon sources and two US river systems with terrestrial organic carbon sources, were ozonated. Several analyses, including 13C-NMR, UV absorbance, fluorescence, hydrophobic/transphilic classification, and potentiometric titrations, were performed before and after ozonation. Ozonation reduced aromatic carbon content, selectively reducing phenolic carbon content. Ozonation of the samples resulted in increased aliphatic, carboxyl, plus acetal and ketal anomeric carbon content and shifted towards less hydrophobic compounds.

  14. AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice

    PubMed Central

    2011-01-01

    obtained from ozone-exposed control mice. Ozone exposure consistently increased phosphorylated AMPK-Thr172 to total AMPK ratio by 80% in control mice. Ozone exposure causes increases in AFC and basolateral membrane Na(+)-K(+)-ATPase abundance in control mice which did not occur in AMPKα1 deficient mice. Conclusions Our results collectively suggest that AMPK activation participates in ozone-induced increases in AFC, inflammation and oxidative stress. Further studies are needed to understand how the AMPK pathway may provide a novel approach for the prevention of ozone-induced lung injury. PMID:21595935

  15. Valve-regulated lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Berndt, D.

    Valve-regulated lead-acid (VRLA) batteries with gelled electrolyte appeared as a niche market during the 1950s. During the 1970s, when glass-fiber felts became available as a further method to immobilize the electrolyte, the market for VRLA batteries expanded rapidly. The immobilized electrolyte offers a number of obvious advantages including the internal oxygen cycle which accommodates the overcharging current without chemical change within the cell. It also suppresses acid stratification and thus opens new fields of application. VRLA batteries, however, cannot be made completely sealed, but require a valve for gas escape, since hydrogen evolution and grid corrosion are unavoidable secondary reactions. These reactions result in water loss, and also must be balanced in order to ensure proper charging of both electrodes. Both secondary reactions have significant activation energies, and can reduce the service life of VRLA batteries, operated at elevated temperature. This effect can be aggravated by the comparatively high heat generation caused by the internal oxygen cycle during overcharging. Temperature control of VRLA batteries, therefore, is important in many applications.

  16. Superoxide generation catalyzed by the ozone-inducible plant peptides analogous to prion octarepeat motif.

    PubMed

    Yokawa, Ken; Kagenishi, Tomoko; Kawano, Tomonori

    2011-04-01

    Ozone-inducible (OI) peptides found in plants contain repeated sequences consisting of a hexa-repeat unit (YGH GGG) repeated 7-9 times in tandem, and each unit tightly binds copper. To date, the biochemical roles for OI peptides are not fully understood. Here, we demonstrated that the hexa-repeat unit from OI peptides behaves as metal-binding motif catalytically active in the O2•--generation. Lastly, possible mechanisms of the reaction and biological consequence of the reactions are discussed by analogy to the action of human prion octarepeat peptides.

  17. Ozone-induced hyperresponsiveness and blockade of M2 muscarinic receptors by eosinophil major basic protein.

    PubMed

    Yost, B L; Gleich, G J; Fryer, A D

    1999-10-01

    Control of airway smooth muscle is provided by parasympathetic nerves that release acetylcholine onto M(3) muscarinic receptors. Acetylcholine release is limited by inhibitory M(2) muscarinic receptors. In antigen-challenged guinea pigs, hyperresponsiveness is due to blockade of neuronal M(2) receptors by eosinophil major basic protein (MBP). Because exposure of guinea pigs to ozone also causes M(2) dysfunction and airway hyperresponsiveness, the role of eosinophils in ozone-induced hyperresponsiveness was tested. Animals were exposed to filtered air or to 2 parts/million ozone for 4 h. Twenty-four hours later, the muscarinic agonist pilocarpine no longer inhibited vagally induced bronchoconstriction in ozone-exposed animals, indicating M(2) dysfunction. M(2) receptor function in ozone-exposed animals was protected by depletion of eosinophils with antibody to interleukin-5 and by pretreatment with antibody to guinea pig MBP. M(2) function was acutely restored by removal of MBP with heparin. Ozone-induced hyperreactivity was also prevented by antibody to MBP and was reversed by heparin. These data show that loss of neuronal M(2) receptor function after ozone is due to release of eosinophil MBP.

  18. Ozone-induced loss of neuronal M2 muscarinic receptor function is prevented by cyclophosphamide.

    PubMed

    Gambone, L M; Elbon, C L; Fryer, A D

    1994-09-01

    We tested the hypothesis that inflammatory cells mediate the loss of neuronal M2 muscarinic receptors in the lung after ozone exposure. Pathogen-free guinea pigs treated with cyclophosphamide (30 mg.kg-1.day-1 i.p. for 7 days) before exposure to ozone were compared with untreated ozone-exposed animals. This dose of cyclophosphamide significantly reduced leukocytes in peripheral blood and bronchoalveolar lavage fluid. Twenty-four hours after ozone, muscarinic receptor function was tested in anesthetized animals. In air-exposed guinea pigs, vagally induced bronchoconstriction was attenuated by the muscarinic agonist pilocarpine (0.1-100 micrograms/kg i.v.) and potentiated by the selective M2 antagonist gallamine (0.1-10 mg/kg i.v.), indicating that the neuronal M2 muscarinic receptors were functioning. These responses were significantly reduced after ozone, indicating loss of neuronal M2 muscarinic receptor function. However, in those animals treated with cyclophosphamide, M2 muscarinic receptor function was not altered by ozone. These data suggest that ozone-induced loss of neuronal muscarinic receptor function is mediated via inflammatory cells and that the link between ozone-induced hyperresponsiveness and inflammation may be the neuronal M2 muscarinic receptor.

  19. Mechanisms of ozone-induced bronchial hyperreactivity to muscarinic agonists in the guinea pig

    SciTech Connect

    Roum, J.H.

    1986-01-01

    Bronchial hyperreactivity, a chief characteristic of asthma, is poorly understood mechanistically. Its development in ozone-exposed guinea pigs was studied in this dissertation research. Reactivity was assessed in awake, spontaneously breathing animals by measuring specific airway resistance (SRaw) as a function of increasing muscarinic bronchoconstrictor challenge. In the first study, improvements in the reactivity measurement were seen by using (1) propranolol pretreatment (10 mg/kg IP, 1/2 hr before measurement) and (2) intravenous (rather than aerosolized) muscarinic challenge. Both (1) decreased its population wide variation and (2) increased its intra-animal reproducibility. Secondly, characteristics of ozone-induced bronchial hyperreactivity, such as (1) its airway mucosal permeability dependence, (2) its time course of development, and (3) its ozone-dose dependence were studied. The relationship between airway mucosa neutrophilic infiltration and the development of this hyperreactivity was examined in the third and fourth study. In the third, a time course study showed that development of hyperreactivity occurred before the neutrophilic infiltration phase, and correlated best with a decrease in identifiable mucosal goblet cells and increase in identifiable mucosoal mast cells. In the fourth, the development of ozone-induced hyperreactivity in animals made granulocytopenic with cyclophosphamide and cortisone acetate treatment was studied. In the final study, the effects of indomethacin on the development of this hyperreactivity was assessed.

  20. Effects of N-Acetylcysteine in Ozone-Induced Chronic Obstructive Pulmonary Disease Model

    PubMed Central

    Seiffert, Joanna M.; Zhu, Jie; Clarke, Colin; Chang, Yan; Bhavsar, Pank; Adcock, Ian; Zhang, Junfeng; Zhou, Xin; Chung, Kian Fan

    2013-01-01

    Introduction Chronic exposure to high levels of ozone induces emphysema and chronic inflammation in mice. We determined the recovery from ozone-induced injury and whether an antioxidant, N-acetylcysteine (NAC), could prevent or reverse the lung damage. Methods Mice were exposed to ozone (2.5 ppm, 3 hours/12 exposures, over 6 weeks) and studied 24 hours (24h) or 6 weeks (6W) later. Nac (100 mg/kg, intraperitoneally) was administered either before each exposure (preventive) or after completion of exposure (therapeutic) for 6 weeks. Results After ozone exposure, there was an increase in functional residual capacity, total lung volume, and lung compliance, and a reduction in the ratio of forced expiratory volume at 25 and 50 milliseconds to forced vital capacity (FEV25/FVC, FEV50/FVC). Mean linear intercept (Lm) and airway hyperresponsiveness (AHR) to acetylcholine increased, and remained unchanged at 6W after cessation of exposure. Preventive NAC reduced the number of BAL macrophages and airway smooth muscle (ASM) mass. Therapeutic NAC reversed AHR, and reduced ASM mass and apoptotic cells. Conclusion Emphysema and lung function changes were irreversible up to 6W after cessation of ozone exposure, and were not reversed by NAC. The beneficial effects of therapeutic NAC may be restricted to the ASM. PMID:24260479

  1. Ozone-Induced Dissociation of Conjugated Lipids Reveals Significant Reaction Rate Enhancements and Characteristic Odd-Electron Product Ions

    NASA Astrophysics Data System (ADS)

    Pham, Huong T.; Maccarone, Alan T.; Campbell, J. Larry; Mitchell, Todd W.; Blanksby, Stephen J.

    2013-02-01

    Ozone-induced dissociation (OzID) is an alternative ion activation method that relies on the gas phase ion-molecule reaction between a mass-selected target ion and ozone in an ion trap mass spectrometer. Herein, we evaluated the performance of OzID for both the structural elucidation and selective detection of conjugated carbon-carbon double bond motifs within lipids. The relative reactivity trends for [M + X]+ ions (where X = Li, Na, K) formed via electrospray ionization (ESI) of conjugated versus nonconjugated fatty acid methyl esters (FAMEs) were examined using two different OzID-enabled linear ion-trap mass spectrometers. Compared with nonconjugated analogues, FAMEs derived from conjugated linoleic acids were found to react up to 200 times faster and to yield characteristic radical cations. The significantly enhanced reactivity of conjugated isomers means that OzID product ions can be observed without invoking a reaction delay in the experimental sequence (i.e., trapping of ions in the presence of ozone is not required). This possibility has been exploited to undertake neutral-loss scans on a triple quadrupole mass spectrometer targeting characteristic OzID transitions. Such analyses reveal the presence of conjugated double bonds in lipids extracted from selected foodstuffs. Finally, by benchmarking of the absolute ozone concentration inside the ion trap, second order rate constants for the gas phase reactions between unsaturated organic ions and ozone were obtained. These results demonstrate a significant influence of the adducting metal on reaction rate constants in the fashion Li > Na > K.

  2. Regulating for the long term: SMCRA and acid mine drainage

    SciTech Connect

    Shea, C.W.

    1995-12-31

    With the passage of the Surface Mining Control and Reclamation Act of 1977 (SMCRA), regulators and industry representatives expected to solve the problem of pollution of the Nation`s waterways caused by acidic discharges from coal mines. Eighteen years after the passage of SMCRA, hard issues of predicting, regulating and treating acid mine drainage remain. Acid mine drainage is most common in the coal seams of the Midwest and Appalachia: Pennsylvania, West Virginia, Maryland, Ohio, Illinois, and Tennessee. This article discusses regulation of coal mines and acid mine drainage for the long term.

  3. 20-HETE Mediates Ozone-Induced, Neutrophil-Independent Airway Hyper-Responsiveness in Mice

    PubMed Central

    Cooper, Philip R.; Mesaros, A. Clementina; Zhang, Jie; Christmas, Peter; Stark, Christopher M.; Douaidy, Karim; Mittelman, Michael A.; Soberman, Roy J.; Blair, Ian A.; Panettieri, Reynold A.

    2010-01-01

    Background Ozone, a pollutant known to induce airway hyper-responsiveness (AHR), increases morbidity and mortality in patients with obstructive airway diseases and asthma. We postulate oxidized lipids mediate in vivo ozone-induced AHR in murine airways. Methodology/Principal Findings Male BALB/c mice were exposed to ozone (3 or 6 ppm) or filtered air (controls) for 2 h. Precision cut lung slices (PCLS; 250 µm thickness) containing an intrapulmonary airway (∼0.01 mm2 lumen area) were prepared immediately after exposure or 16 h later. After 24 h, airways were contracted to carbachol (CCh). Log EC50 and Emax values were then calculated by measuring the airway lumen area with respect to baseline. In parallel studies, dexamethasone (2.5 mg/kg), or 1-aminobenzotriazol (ABT) (50 mg/kg) were given intraperitoneal injection to naïve mice 18 h prior to ozone exposure. Indomethacin (10 mg/kg) was administered 2 h prior. Cell counts, cytokine levels and liquid chromatography-mass spectrometry (LC-MS) for lipid analysis were assessed in bronchoalveolar lavage (BAL) fluid from ozone exposed and control mice. Ozone acutely induced AHR to CCh. Dexamethasone or indomethacin had little effect on the ozone-induced AHR; while, ABT, a cytochrome P450 inhibitor, markedly attenuated airway sensitivity. BAL fluid from ozone exposed animals, which did not contain an increase in neutrophils or interleukin (IL)-6 levels, increased airway sensitivity following in vitro incubation with a naïve PCLS. In parallel, significant increases in oxidized lipids were also identified using LC-MS with increases of 20-HETE that were decreased following ABT treatment. Conclusions/Significance These data show that ozone acutely induces AHR to CCh independent of inflammation and is insensitive to steroid treatment or cyclooxygenase (COX) inhibition. BAL fluid from ozone exposed mice mimicked the effects of in vivo ozone exposure that were associated with marked increases in oxidized lipids. 20-HETE plays

  4. Intercontinental trans-boundary contributions to ozone-induced crop yield losses in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Hollaway, M. J.; Arnold, S. R.; Challinor, A. J.; Emberson, L. D.

    2011-08-01

    burning emissions may make important contributions to ozone-induced crop yield reductions. Our results demonstrate that local air quality and emission control strategies have the potential to partly alleviate ozone-induced crop yield loss in continents downstream, in addition to effectively mitigating local ozone-induced yield losses.

  5. Abscisic Acid and Stomatal Regulation 1

    PubMed Central

    Kriedemann, P. E.; Loveys, B. R.; Fuller, G. L.; Leopold, A. C.

    1972-01-01

    The closure of stomata by abscisic acid was examined in several species of plants through measurements of CO2 and H2O exchange by the leaf. The onset of closure was very rapid, beginning at 3 minutes from the time of abscisic acid application to the cut base of the leaf of corn, or at 8 or 9 minutes for bean, Rumex and sugarbeet; rose leaves were relatively slow at 32 minutes. The timing and the concentration of abscisic acid needed to cause closure were related to the amounts of endogenous abscisic acid in the leaf. Closure was obtained in bean leaves with 8.9 picomoles/cm2. (+)-Abscisic acid had approximately twice the activity of the racemic material. The methyl ester of abscisic acid was inactive, and trans-abscisic acid was likewise inactive. The effects of stress on levels of endogenous abscisic acid, and the ability of very small amounts of abscisic acid to cause rapid closure suggests that stomatal control is a regulatory function of this hormone. PMID:16658058

  6. Lysophosphatidic Acid Regulation and Roles in Human Prostate Cancer

    DTIC Science & Technology

    2005-01-01

    be generated by other pathways. LPA is produced from phosphatidic acid 4 ") (PA) in activated platelets and ovarian and prostate cancer cells by...material. Appendix 1 JCB in revision 2 ABSTRACT The bioactive phospholipids, lysophosphatidic acid (LPA) and phosphatidic acid (PA), regulate pivotal...glycerolipid synthesis, abundant evidence now indicates that bioactive LPA can also be generated by other pathways. LPA is produced from phosphatidic acid (PA

  7. The Role of Lipid Hydroperoxides in Ozone-Induced Increases in Glutathione Redox Potential in Human Airway Epithelial Cells

    EPA Science Inventory

    Human exposure to tropospheric ozone pollution is of global public health concern. Exposure to ozone induces functional decrements and inflammatory responses in the respiratory tract that are thought to occur through oxidative mechanisms. While it is known that ozone oxidizes p...

  8. A review of ozone-induced effects on the forests of central Mexico.

    PubMed

    de Bauer, María de Lourdes; Hernández-Tejeda, Tomás

    2007-06-01

    The first report on oxidant-induced plant damage in the Valley of Mexico was presented over 30 years ago. Ozone is known to occur in the Mexico City Metropolitan Area and elsewhere as the cause of chlorotic mottling on pine needles that are 2 years old or older as observed in 1976 on Pinus hartwegii and Pinus leiophylla. Visible evidences for the negative effects of ozone on the vegetation of central Mexico include foliar injury expressed as chlorotic mottling and premature defoliation on pines, a general decline of sacred fir, visible symptoms on native forest broadleaved species (e.g. Mexican black cherry). Recent investigations have also indicated that indirect effects are occurring such as limited root colonization by symbiotic fungi on ozone-damaged P. hartwegii trees and a negative influence of the pollutant on the natural regeneration of this species. The negative ozone-induced effects on the vegetation will most likely continue to increase.

  9. Ozone-induced changes in the pulmonary clearance of (99m)Tc-DTPA in man

    SciTech Connect

    Kehrl, H.R.; Vincent, L.M.; Kowalsky, R.J.; Horstman, D.H.; O'Neil, J.J.

    1988-05-01

    Ozone is a respiratory irritant that has been shown in animals to increase the premeability of the respiratory epithelium. In the study the authors have recently reported that respiratory epithelial permeability was similarly affected in eight healthy non-smoking young men exposed to ozone (ARRD, 135 (1987) 1124-8). Permeability was evaluated by determining the pulmonary clearance of inhaled aerosolized 99mTc-DTPA with sequential posterior lung imaging by a computer-assisted gamma camera. In a randomized crossover design, 16 young men were exposed for 2 h to purified air and 0.4 ppm ozone while performing intermittent high intensity treadmill exercise; forced vital capacity (FVC) was measured before and at the end of exposures. The results demonstrate that ozone exposure increased respiratory epithelial permeability. Such an increase may be a manifestation of direct ozone-induced epithelial-cell injury, lung inflammation, or both.

  10. Evidence of widespread ozone-induced visible injury on plants in Beijing, China.

    PubMed

    Feng, Zhaozhong; Sun, Jingsong; Wan, Wuxing; Hu, Enzhu; Calatayud, Vicent

    2014-10-01

    Despite the high ozone levels measured in China, and in Beijing in particular, reports of ozone-induced visible injury in vegetation are very scarce. Visible injury was investigated on July and August 2013 in the main parks, forest and agricultural areas of Beijing. Ozone injury was widespread in the area, being observed in 28 different species. Symptoms were more frequent in rural areas and mountains from northern Beijing, downwind from the city, and less frequent in city gardens. Among crops, injury to different types of beans (genera Phaseolus, Canavalia and Vigna) was common, and it was also observed in watermelon, grape vine, and in gourds. Native species such as ailanthus, several pines and ash species were also symptomatic. The black locust, the rose of Sharon and the Japanese morning glory were among the injured ornamental plants. Target species for broader bio-monitoring surveys in temperate China have been identified. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Intercontinental trans-boundary contributions to ozone-induced crop yield losses in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Hollaway, M. J.; Arnold, S. R.; Challinor, A. J.; Emberson, L. D.

    2012-01-01

    Using a global atmospheric chemistry model, we have quantified for the first time, intercontinental transboundary contributions to crop ozone exposure and subsequent yield reductions in the Northern Hemisphere. We apply four metrics (AOT40, M7, M12, W126) to assess the impacts of 100% reductions in anthropogenic NOx emissions from North (N) America, South East (SE) Asia and Europe on global and regional exposure of 6 major agricultural crop types to surface ozone, and resultant crop production losses during the year 2000 growing season. Using these metrics, model calculations show that for wheat, rice, cotton and potato, 100 % reductions in SE Asian anthropogenic NOx emissions tend to produce the greatest global reduction in crop production losses (42.3-95.2%), and a 100 % reduction to N~American anthropogenic NOx emissions results in the greatest global impact on crop production losses for maize and soybean (59.2-85.9%). A 100% reduction in N~American anthropogenic NOx emissions produces the largest transboundary impact, resulting in European production loss reductions of between 14.2% and 63.2%. European NOx emissions tend to produce a smaller transboundary impact, due to inefficiency of transport from the European domain. The threshold nature of the AOT40 ozone-exposure metric results in strong dependence of non-local emissions impacts on the local ozone concentration distribution. Our calculations of absolute crop production change under emission reduction scenarios differ between the metrics used, however we find the relative importance of each region's transboundary impact remains robust between metrics. Our results demonstrate that local air quality and emission control strategies have the potential to partly alleviate ozone-induced crop yield loss in continents downstream, in addition to effectively mitigating local ozone-induced production losses.

  12. Ozone-Induced Nasal Type 2 Immunity in Mice Is Dependent on Innate Lymphoid Cells.

    PubMed

    Kumagai, Kazuyoshi; Lewandowski, Ryan; Jackson-Humbles, Daven N; Li, Ning; Van Dyken, Steven J; Wagner, James G; Harkema, Jack R

    2016-06-01

    Epidemiological studies suggest that elevated ambient concentrations of ozone are associated with activation of eosinophils in the nasal airways of atopic and nonatopic children. Mice repeatedly exposed to ozone develop eosinophilic rhinitis and type 2 immune responses. In this study, we determined the role of innate lymphoid cells (ILCs) in the pathogenesis of ozone-induced eosinophilic rhinitis by using lymphoid-sufficient C57BL/6 mice, Rag2(-/-) mice that are devoid of T cells and B cells, and Rag2(-/-)Il2rg(-/-) mice that are depleted of all lymphoid cells including ILCs. The animals were exposed to 0 or 0.8 ppm ozone for 9 consecutive weekdays (4 h/d). Mice were killed 24 hours after exposure, and nasal tissues were selected for histopathology and gene expression analysis. ILC-sufficient C57BL/6 and Rag2(-/-) mice exposed to ozone developed marked eosinophilic rhinitis and epithelial remodeling (e.g., epithelial hyperplasia and mucous cell metaplasia). Chitinase-like proteins and alarmins (IL-33, IL-25, and thymic stromal lymphopoietin) were also increased morphometrically in the nasal epithelium of ozone-exposed C57BL/6 and Rag2(-/-) mice. Ozone exposure elicited increased expression of Il4, Il5, Il13, St2, eotaxin, MCP-2, Gob5, Arg1, Fizz1, and Ym2 mRNA in C57BL/6 and Rag2(-/-) mice. In contrast, ozone-exposed ILC-deficient Rag2(-/-)Il2rg(-/-) mice had no nasal lesions or overexpression of Th2- or ILC2-related transcripts. These results indicate that ozone-induced eosinophilic rhinitis, nasal epithelial remodeling, and type 2 immune activation are dependent on ILCs. To the best of our knowledge, this is the first study to demonstrate that ILCs play an important role in the nasal pathology induced by repeated ozone exposure.

  13. Ozone induces glucose intolerance and systemic metabolic effects in young and aged Brown Norway rats.

    PubMed

    Bass, V; Gordon, C J; Jarema, K A; MacPhail, R C; Cascio, W E; Phillips, P M; Ledbetter, A D; Schladweiler, M C; Andrews, D; Miller, D; Doerfler, D L; Kodavanti, U P

    2013-12-15

    Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α2-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2>1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation.

  14. Inhibitory effect of hydrogen sulfide on ozone-induced airway inflammation, oxidative stress, and bronchial hyperresponsiveness.

    PubMed

    Zhang, Pengyu; Li, Feng; Wiegman, Coen H; Zhang, Min; Hong, Yan; Gong, Jicheng; Chang, Yan; Zhang, Junfeng Jim; Adcock, Ian; Chung, Kian Fan; Zhou, Xin

    2015-01-01

    Exposure to ozone has been associated with airway inflammation, oxidative stress, and bronchial hyperresponsiveness. The goal of this study was to examine whether these adverse effects of ozone could be prevented or reversed by hydrogen sulfide (H2S) as a reducing agent. The H2S donor sodium (NaHS) (2 mg/kg) or vehicle (PBS) was intraperitoneally injected into mice 1 hour before and after 3-hour ozone (2.5 ppm) or air exposure, and the mice were studied 24 hours later. Preventive and therapeutic treatment with NaHS reduced the ozone-induced increases in the total cells, including neutrophils and macrophages; this treatment also reduced levels of cytokines, including TNF-α, chemokine (C-X-C motif) ligand 1, IL-6, and IL-1β levels in bronchial alveolar lavage fluid; inhibited bronchial hyperresponsiveness; and attenuated ozone-induced increases in total malondialdehyde in bronchoalveolar lavage fluid and decreases in the ratio of reduced glutathione/oxidized glutathione in the lung. Ozone exposure led to decreases in the H2S production rate and in mRNA and protein levels of cystathionine-β-synthetase and cystathionine-γ-lyase in the lung. These effects were prevented and reversed by NaHS treatment. Furthermore, NaHS prevented and reversed the phosphorylation of p38 mitogen-activated protein kinase and heat shock protein 27. H2S may have preventive and therapeutic value in the treatment of airway diseases that have an oxidative stress basis.

  15. Regulation of uric acid metabolism and excretion.

    PubMed

    Maiuolo, Jessica; Oppedisano, Francesca; Gratteri, Santo; Muscoli, Carolina; Mollace, Vincenzo

    2016-06-15

    Purines perform many important functions in the cell, being the formation of the monomeric precursors of nucleic acids DNA and RNA the most relevant one. Purines which also contribute to modulate energy metabolism and signal transduction, are structural components of some coenzymes and have been shown to play important roles in the physiology of platelets, muscles and neurotransmission. All cells require a balanced quantity of purines for growth, proliferation and survival. Under physiological conditions the enzymes involved in the purine metabolism maintain in the cell a balanced ratio between their synthesis and degradation. In humans the final compound of purines catabolism is uric acid. All other mammals possess the enzyme uricase that converts uric acid to allantoin that is easily eliminated through urine. Overproduction of uric acid, generated from the metabolism of purines, has been proven to play emerging roles in human disease. In fact the increase of serum uric acid is inversely associated with disease severity and especially with cardiovascular disease states. This review describes the enzymatic pathways involved in the degradation of purines, getting into their structure and biochemistry until the uric acid formation. Copyright © 2015. Published by Elsevier Ireland Ltd.

  16. Regulation of hormone metabolism in Arabidopsis seeds: phytochrome regulation of abscisic acid metabolism and abscisic acid regulation of gibberellin metabolism.

    PubMed

    Seo, Mitsunori; Hanada, Atsushi; Kuwahara, Ayuko; Endo, Akira; Okamoto, Masanori; Yamauchi, Yukika; North, Helen; Marion-Poll, Annie; Sun, Tai-Ping; Koshiba, Tomokazu; Kamiya, Yuji; Yamaguchi, Shinjiro; Nambara, Eiji

    2006-11-01

    In a wide range of plant species, seed germination is regulated antagonistically by two plant hormones, abscisic acid (ABA) and gibberellin (GA). In the present study, we have revealed that ABA metabolism (both biosynthesis and inactivation) was phytochrome-regulated in an opposite fashion to GA metabolism during photoreversible seed germination in Arabidopsis. Endogenous ABA levels were decreased by irradiation with a red (R) light pulse in dark-imbibed seeds pre-treated with a far-red (FR) light pulse, and the reduction in ABA levels in response to R light was inhibited in a phytochrome B (PHYB)-deficient mutant. Expression of an ABA biosynthesis gene, AtNCED6, and the inactivation gene, CYP707A2, was regulated in a photoreversible manner, suggesting a key role for the genes in PHYB-mediated regulation of ABA metabolism. Abscisic acid-deficient mutants such as nced6-1, aba2-2 and aao3-4 exhibited an enhanced ability to germinate relative to wild type when imbibed in the dark after irradiation with an FR light pulse. In addition, the ability to synthesize GA was improved in the aba2-2 mutant compared with wild type during dark-imbibition after an FR light pulse. Activation of GA biosynthesis in the aba2-2 mutant was also observed during seed development. These data indicate that ABA is involved in the suppression of GA biosynthesis in both imbibed and developing seeds. Spatial expression patterns of the AtABA2 and AAO3 genes, responsible for last two steps of ABA biosynthesis, were distinct from that of the GA biosynthesis gene, AtGA3ox2, in both imbibed and developing seeds, suggesting that biosynthesis of ABA and GA in seeds occurs in different cell types.

  17. Lysophosphatidic Acid Regulation and Roles in Human Prostate Cancer

    DTIC Science & Technology

    2006-08-01

    DAMD17-02-1-0060 TITLE: Lysophosphatidic Acid Regulation and Roles in Human Prostate Cancer PRINCIPAL INVESTIGATOR: Sarah Spiegel...Final 3. DATES COVERED (From - To) 2 Jan 2002 – 31 Jul 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Lysophosphatidic Acid Regulation and Roles ...important role in the pathophysiology of prostate cancer. Therefore, targeting this kinase, offers additional therapeutic benefits in treatment of

  18. Novel regulator of enterohepatic bile acid signaling protects against hypercholesterolemia.

    PubMed

    Dawson, Paul A

    2013-06-04

    Hypercholesterolemia is a major cause of cardiovascular disease and can be treated by targeting bile acid and cholesterol metabolism. Vergnes et al. (2013) now identify Diet1 as a novel regulator of fibroblast growth factor 15/19 production and bile acid biosynthesis.

  19. Regulation of renal amino acid transporters during metabolic acidosis.

    PubMed

    Moret, Caroline; Dave, Mital H; Schulz, Nicole; Jiang, Jean X; Verrey, Francois; Wagner, Carsten A

    2007-02-01

    The kidney plays a major role in acid-base homeostasis by adapting the excretion of acid equivalents to dietary intake and metabolism. Urinary acid excretion is mediated by the secretion of protons and titratable acids, particularly ammonia. NH(3) is synthesized in proximal tubule cells from glutamine taken up via specific amino acid transporters. We tested whether kidney amino acid transporters are regulated in mice in which metabolic acidosis was induced with NH(4)Cl. Blood gas and urine analysis confirmed metabolic acidosis. Real-time RT-PCR was performed to quantify the mRNAs of 16 amino acid transporters. The mRNA of phosphoenolpyruvate carboxykinase (PEPCK) was quantified as positive control for the regulation and that of GAPDH, as internal standard. In acidosis, the mRNA of kidney system N amino acid transporter SNAT3 (SLC38A3/SN1) showed a strong induction similar to that of PEPCK, whereas all other tested mRNAs encoding glutamine or glutamate transporters were unchanged or reduced in abundance. At the protein level, Western blotting and immunohistochemistry demonstrated an increased abundance of SNAT3 and reduced expression of the basolateral cationic amino acid/neutral amino acid exchanger subunit y(+)-LAT1 (SLC7A7). SNAT3 was localized to the basolateral membrane of the late proximal tubule S3 segment in control animals, whereas its expression was extended to the earlier S2 segment of the proximal tubule during acidosis. Our results suggest that the selective regulation of SNAT3 and y(+)LAT1 expression may serve a major role in the renal adaptation to acid secretion and thus for systemic acid-base balance.

  20. Ozone induces glucose intolerance and systemic metabolic effects in young and aged brown Norway rats

    SciTech Connect

    Bass, V.; Gordon, C.J.; Jarema, K.A.; MacPhail, R.C.; Cascio, W.E.; Phillips, P.M.; Ledbetter, A.D.; Schladweiler, M.C.; Andrews, D.; Miller, D.; Doerfler, D.L.; Kodavanti, U.P.

    2013-12-15

    Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α{sub 2}-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2 > 1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation. - Highlights: • Air pollutants have been associated with increased diabetes in humans. • Acute ozone exposure produces profound metabolic alterations in rats. • Age influences metabolic risk factors in aging BN rats. • Acute metabolic effects are reversible and repeated exposure reduces these effects. • Ozone

  1. Ozone-induced oxidative modification of fibrinogen: role of the D regions.

    PubMed

    Rosenfeld, Mark A; Shchegolikhin, Alexander N; Bychkova, Anna V; Leonova, Vera B; Biryukova, Marina I; Kostanova, Elizaveta A

    2014-12-01

    Native fibrinogen is a key blood plasma protein whose main function is to maintain hemostasis by virtue of producing cross-linked fibrin clots under the influence of thrombin and fibrin-stabilizing factor (FXIIIa). The aim of this study was to investigate mechanisms of impairment of both the molecular structure and the spatial organization of fibrinogen under ozone-induced oxidation. FTIR analysis showed that ozone treatment of the whole fibrinogen molecule results in the growth of hydroxyl, carbonyl, and carboxyl group content. A similar analysis of fibrinogen D and E fragments isolated from the oxidized protein also revealed transformation of distinct important functional groups. In particular, a remarkable decay of N-H groups within the peptide backbone was observed along with a lowering of the content of C-H groups belonging to either the aromatic moieties or the aliphatic chain CH2 and CH3 units. The model experiments performed showed that the rather unexpected decay of the aliphatic CH units might be caused by the action of hydroxyl radicals, these being produced in the water solution from ozone. The observed dissimilarities in the shapes of amide I bands of the fibrinogen D and E fragments before and after ozone treatment are interpreted in terms of feasible local conformational changes affecting the secondary structure of the protein. Taken as a whole, the FTIR data suggests that the terminal D fragments of fibrinogen are markedly more susceptible to the ozone-induced oxidation than the central E fragment. The data on elastic and dynamic light scattering provide evidence that, in the presence of FXIIIa, both the unoxidized and the oxidized fibrinogen molecules bind to one another in an "end-to-end" fashion to form the flexible covalently cross-linked fibrinogen homopolymers. The γ and α polypeptide chains of the oxidized fibrinogen proved to be involved in the enzymatic cross-linking more readily than those of unaffected fibrinogen. The experimental data

  2. ACUTE OZONE-INDUCED INFLAMMATORY GENE EXPRESSION IN THE RAT LUNG IS NOT RELATED TO LEVELS OF ANTIOXIDANTS IN THE LAVAGE FLUID

    EPA Science Inventory

    ABSTRACT BODY: Ozone causes oxidative stress and lung inflammation. We hypothesized that rat strains with or without genetic susceptibility to cardiovascular disease will have different antioxidant levels in alveolar lining, and that ozone induced inflammatory gene expression wil...

  3. ACUTE OZONE-INDUCED INFLAMMATORY GENE EXPRESSION IN THE RAT LUNG IS NOT RELATED TO LEVELS OF ANTIOXIDANTS IN THE LAVAGE FLUID

    EPA Science Inventory

    ABSTRACT BODY: Ozone causes oxidative stress and lung inflammation. We hypothesized that rat strains with or without genetic susceptibility to cardiovascular disease will have different antioxidant levels in alveolar lining, and that ozone induced inflammatory gene expression wil...

  4. Regulation of amino acid metabolic enzymes and transporters in plants.

    PubMed

    Pratelli, Réjane; Pilot, Guillaume

    2014-10-01

    Amino acids play several critical roles in plants, from providing the building blocks of proteins to being essential metabolites interacting with many branches of metabolism. They are also important molecules that shuttle organic nitrogen through the plant. Because of this central role in nitrogen metabolism, amino acid biosynthesis, degradation, and transport are tightly regulated to meet demand in response to nitrogen and carbon availability. While much is known about the feedback regulation of the branched biosynthesis pathways by the amino acids themselves, the regulation mechanisms at the transcriptional, post-transcriptional, and protein levels remain to be identified. This review focuses mainly on the current state of our understanding of the regulation of the enzymes and transporters at the transcript level. Current results describing the effect of transcription factors and protein modifications lead to a fragmental picture that hints at multiple, complex levels of regulation that control and coordinate transport and enzyme activities. It also appears that amino acid metabolism, amino acid transport, and stress signal integration can influence each other in a so-far unpredictable fashion.

  5. Platelet adhesion and protein adsorption on silicone rubber surface by ozone-induced grafted polymerization with carboxybetaine monomer.

    PubMed

    Zhou, Jun; Yuan, Jiang; Zang, Xiaopeng; Shen, Jian; Lin, Sicong

    2005-03-10

    Platelet adhesion and protein adsorption on the silicone rubber film grafted with N,N'-dimethyl-N-methacryloyloxyethyl-N-(2-carboxyethyl) ammonium (DMMCA) was studied. The grafting was carried out by means of ozone-induced method and was confirmed by ATR-FTIR and XPS investigations. The grafted films possessed relatively hydrophilic surface revealed by contact angle measurement. The blood compatibility of the grafted film was evaluated in vitro by platelet adhesion in platelet-rich plasma (PRP) and protein absorption in bovine fibrinogen (BFG) using silicone film as the reference. No substantial platelet adhesion was observed for the grafted films incubated in PRP for 60 and 180 min. The protein absorption was also significantly reduced after incubated in bovine fibrinogen for 60 min. Both the results indicated that the blood compatibility of silicone rubber was greatly improved by ozone-induced grafting of carboxybetaine zwitterionic polymer onto its surface.

  6. Impact of diet on ozone-induced pulmonary and systemic effects in female Brown Norway (BN) rats

    EPA Science Inventory

    Impact of diet on ozone-induced pulmonary and systemic effects in female Brown Norway (BN) ratsV.L. Bass1, M.C. Schladweiler2, S. Snow5, C.J. Gordon4, K.A. Jarema4, P. Phillips4, A.D. Ledbetter2, D.B. Miller3, J.E. Richards2, U.P. Kodavanti2. 1. SPH, UNC, Chapel Hill2. EPHD, NHE...

  7. Impact of diet on ozone-induced pulmonary and systemic effects in female Brown Norway (BN) rats

    EPA Science Inventory

    Impact of diet on ozone-induced pulmonary and systemic effects in female Brown Norway (BN) ratsV.L. Bass1, M.C. Schladweiler2, S. Snow5, C.J. Gordon4, K.A. Jarema4, P. Phillips4, A.D. Ledbetter2, D.B. Miller3, J.E. Richards2, U.P. Kodavanti2. 1. SPH, UNC, Chapel Hill2. EPHD, NHE...

  8. Mechanisms of Gene Regulation by Fatty Acids12

    PubMed Central

    Georgiadi, Anastasia; Kersten, Sander

    2012-01-01

    Consumption of specific dietary fatty acids has been shown to influence risk and progression of several chronic diseases, such as cardiovascular disease, obesity, cancer, and arthritis. In recent years, insights into the mechanisms underlying the biological effects of fatty acids have improved considerably and have provided the foundation for the emerging concept of fatty acid sensing, which can be interpreted as the property of fatty acids to influence biological processes by serving as signaling molecules. An important mechanism of fatty acid sensing is via stimulation or inhibition of DNA transcription. Here, we focus on fatty acid sensing via regulation of gene transcription and address the role of peroxisome proliferator–activated receptors, sterol regulatory element binding protein 1, Toll-like receptor 4, G protein–coupled receptors, and other putative mediators. PMID:22516720

  9. Dual p38/JNK Mitogen Activated Protein Kinase Inhibitors Prevent Ozone-Induced Airway Hyperreactivity in Guinea Pigs

    PubMed Central

    Verhein, Kirsten C.; Salituro, Francesco G.; Ledeboer, Mark W.; Fryer, Allison D.; Jacoby, David B.

    2013-01-01

    Ozone exposure causes airway hyperreactivity and increases hospitalizations resulting from pulmonary complications. Ozone reacts with the epithelial lining fluid and airway epithelium to produce reactive oxygen species and lipid peroxidation products, which then activate cell signaling pathways, including the mitogen activated protein kinase (MAPK) pathway. Both p38 and c-Jun NH2 terminal kinase (JNK) are MAPK family members that are activated by cellular stress and inflammation. To test the contribution of both p38 and JNK MAPK to ozone-induced airway hyperreactivity, guinea pigs were pretreated with dual p38 and JNK MAPK inhibitors (30 mg/kg, ip) 60 minutes before exposure to 2 ppm ozone or filtered air for 4 hours. One day later airway reactivity was measured in anesthetized animals. Ozone caused airway hyperreactivity one day post-exposure, and blocking p38 and JNK MAPK completely prevented ozone-induced airway hyperreactivity. Blocking p38 and JNK MAPK also suppressed parasympathetic nerve activity in air exposed animals, suggesting p38 and JNK MAPK contribute to acetylcholine release by airway parasympathetic nerves. Ozone inhibited neuronal M2 muscarinic receptors and blocking both p38 and JNK prevented M2 receptor dysfunction. Neutrophil influx into bronchoalveolar lavage was not affected by MAPK inhibitors. Thus p38 and JNK MAPK mediate ozone-induced airway hyperreactivity through multiple mechanisms including prevention of neuronal M2 receptor dysfunction. PMID:24058677

  10. Dual p38/JNK mitogen activated protein kinase inhibitors prevent ozone-induced airway hyperreactivity in guinea pigs.

    PubMed

    Verhein, Kirsten C; Salituro, Francesco G; Ledeboer, Mark W; Fryer, Allison D; Jacoby, David B

    2013-01-01

    Ozone exposure causes airway hyperreactivity and increases hospitalizations resulting from pulmonary complications. Ozone reacts with the epithelial lining fluid and airway epithelium to produce reactive oxygen species and lipid peroxidation products, which then activate cell signaling pathways, including the mitogen activated protein kinase (MAPK) pathway. Both p38 and c-Jun NH2 terminal kinase (JNK) are MAPK family members that are activated by cellular stress and inflammation. To test the contribution of both p38 and JNK MAPK to ozone-induced airway hyperreactivity, guinea pigs were pretreated with dual p38 and JNK MAPK inhibitors (30 mg/kg, i.p.) 60 minutes before exposure to 2 ppm ozone or filtered air for 4 hours. One day later airway reactivity was measured in anesthetized animals. Ozone caused airway hyperreactivity one day post-exposure, and blocking p38 and JNK MAPK completely prevented ozone-induced airway hyperreactivity. Blocking p38 and JNK MAPK also suppressed parasympathetic nerve activity in air exposed animals, suggesting p38 and JNK MAPK contribute to acetylcholine release by airway parasympathetic nerves. Ozone inhibited neuronal M2 muscarinic receptors and blocking both p38 and JNK prevented M2 receptor dysfunction. Neutrophil influx into bronchoalveolar lavage was not affected by MAPK inhibitors. Thus p38 and JNK MAPK mediate ozone-induced airway hyperreactivity through multiple mechanisms including prevention of neuronal M2 receptor dysfunction.

  11. The effect of platelet activating factor antagonist on ozone-induced airway inflammation and bronchial hyperresponsiveness in guinea pigs

    SciTech Connect

    Tan, W.C.; Bethel, R.A. )

    1992-10-01

    We investigated the role of platelet-activating factor (PAF) in ozone-induced airway responses by examining the effects of L659,989, a potent PAF antagonist, on bronchial hyperresponsiveness and airway inflammation. Twenty-four male guinea pigs were studied in four equal groups. Total lung resistance (RL) in intubated and spontaneously breathing animals was measured in a constant-volume body plethysmograph. Dose-response curves to methacholine were determined in all animals at the start of the experiment. These were repeated on a separate day after the following types of treatments: air exposure in Group 1, intraperitoneally administered alcohol and air exposure in Group 2; intraperitoneally administered alcohol and ozone exposure in Group 3, and intraperitoneally administered L659,989 (a specific PAF antagonist), 5 mg/kg dissolved in alcohol, and ozone exposure in Group 4. Bronchoalveolar lavage (BAL) was performed after the second methacholine challenge, and the bronchial mucosa was also examined for inflammatory cells. Exposure to 3 ppm ozone for 2 h resulted in a three-doubling concentration increase in bronchial responsiveness, which was not significantly inhibited by prior treatment with L659,989. Ozone induced a 1.8-fold increase in BAL total cell count, increased eosinophilic influx into the airways, and increased eosinophilic infiltration in the bronchial mucosa, which were all not inhibited by L659,989 pretreatment. The results suggest that PAF may not have an essential role in ozone-induced airway hyperresponsiveness and nonallergic airway inflammation.

  12. Renal regulation of acid-base balance.

    PubMed

    Yucha, Carolyn

    2004-01-01

    Because maintaining a normal body pH is essential to the efficient functioning of many physiologic processes, the body has a number of mechanisms that prevent pH fluctuations. Some of these prevent minute-to-minute pH fluctuations over the course of the day, whereas others maintain pH balance from day to day. The kidney plays a key role in both processes. The renal process of bicarbonate reclamation prevents the loss of bicarbonate in the urine and, thus, maintains plasma levels of one substrate that is instrumental to preventing minute-to-minute pH fluctuations. The other renal process, bicarbonate regeneration, replenishes the body's supply of bicarbonate and, thus, maintains pH balance on a day-to-day basis. This article will discuss basic principles of acid-base physiology, the mechanisms that prevent fluctuations in body pH, and the renal processes involved in maintaining a homeostatic pH environment.

  13. Ozone-induced airway hyperresponsiveness and loss of neuronal M2 muscarinic receptor function.

    PubMed

    Schultheis, A H; Bassett, D J; Fryer, A D

    1994-03-01

    The effect of acute ozone exposure on the function of efferent parasympathetic nerves, M3 muscarinic receptors on airway smooth muscle, and inhibitory M2 muscarinic receptors on the parasympathetic nerves was studied. Immediately after exposure to 2.0 ppm ozone for 4 h, guinea pigs became hyperresponsive to electrical stimulation of the vagus nerves. The normal airway response to intravenous cholinergic agonists at this time demonstrates normal M3 receptor function. M2 muscarinic receptors on the nerves, which normally inhibit release of acetylcholine, were dysfunctional after ozone exposure, as demonstrated by the failure of the muscarinic agonist pilocarpine to inhibit, and the failure of the M2 antagonist gallamine to potentiate, vagally mediated bronchoconstriction. Thus, loss of inhibitory M2 muscarinic receptor function after ozone exposure potentiates release of acetylcholine from the vagus nerves, increasing vagally mediated bronchoconstriction. By 14 days, postozone responses to vagal nerve stimulation were not different from those of air-exposed animals and the function of the neuronal M2 muscarinic receptor was normal, confirming that ozone-induced hyperresponsiveness is reversible.

  14. Mechanism of ozone-induced tachypneic response to hypoxia and hypercapnia in conscious dogs

    SciTech Connect

    Lea, L.Y.; Djokic, T.D.; Dumont, C.; Graf, P.D.; Nadel, J.A.

    1980-01-01

    In seven studies on three dogs exercising on a treadmill (1.6 km/h), we studied the effect of ozone on ventilatory responses to hypercapnia and to hypoxia. After ozone exposure (0.67 +- 0.02 ppM by vol; 2 h), the responses of minute volume of ventilation (VE) to progressive hypercapnia and hypoxia were not changed, but the breathing pattern in response to these stimuli changed. We analyzed the breathing pattern by plotting the relationship between VE and tidal volume (VT). During progressive hypercapnia, the slope of VE-VT relationship increased from a control value of 36.1 +- 1.6 (mean +- SE) to 93.5 +- 8.9 min-1 after ozone (n = 7, P less than 0.005); during hypoxia, the slope increased from a control value of 46.1 +- 8.6 to 142.7 +- 18.3 min-1 after ozone (n = 6, P less than 0.005). The ozone-induced tachypneic responses to hypercapnia and hypoxia were not affected by inhalation responses to hypercapnia and hypoxia were not affected by inhalation of atropine sulfate or isoproterenol aerosols, but were completely abolished by bilateral vagal blockade. These findings indicate an effect of ozone on the vagal receptors located in the airways and lungs that causes reflex tachypnea during hypercapnia and hypoxia.

  15. Structural Analysis of Unsaturated Glycosphingolipids Using Shotgun Ozone-Induced Dissociation Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Barrientos, Rodell C.; Vu, Ngoc; Zhang, Qibin

    2017-08-01

    Glycosphingolipids are essential biomolecules widely distributed across biological kingdoms yet remain relatively underexplored owing to both compositional and structural complexity. While the glycan head group has been the subject of most studies, there is paucity of reports on the lipid moiety, particularly the location of unsaturation. In this paper, ozone-induced dissociation mass spectrometry (OzID-MS) implemented in a traveling wave-based quadrupole time-of-flight (Q-ToF) mass spectrometer was applied to study unsaturated glycosphingolipids using shotgun approach. Resulting high resolution mass spectra facilitated the unambiguous identification of diagnostic OzID product ions. Using [M+Na]+ adducts of authentic standards, we observed that the long chain base and fatty acyl unsaturation had distinct reactivity with ozone. The reactivity of unsaturation in the fatty acyl chain was about 8-fold higher than that in the long chain base, which enables their straightforward differentiation. Influence of the head group, fatty acyl hydroxylation, and length of fatty acyl chain on the oxidative cleavage of double bonds was also observed. Application of this technique to bovine brain galactocerebrosides revealed co-isolated isobaric and regioisomeric species, which otherwise would be incompletely identified using contemporary collision-induced dissociation (CID) alone. These results highlight the potential of OzID-MS in glycosphingolipids research, which not only provides complementary structural information to existing CID technique but also facilitates de novo structural determination of these complex biomolecules. [Figure not available: see fulltext.

  16. Dose-response relationship of ozone-induced airway hyperresponsiveness in unanesthetized guinea pigs

    SciTech Connect

    Nishikawa, M.; Suzuki, S.; Ikeda, H.; Fukuda, T.; Suzuki, J.; Okubo, T. )

    1990-06-01

    The effect of ozone dose (the product of ozone concentration and exposure time) on airway responsiveness was examined in unanesthetized, spontaneously breathing guinea pigs. Airway responsiveness was assessed by measuring specific airway resistance (sRaw) as a function of increasing concentration of inhaled methacholine (Mch) aerosol (the concentration of Mch required in order to double the baseline sRaw: PC200Mch). The airway responsiveness was measured before and at 5 min, 5 h, and 24 h after exposure. A 30-min exposure to 1 ppm ozone (dose 30 ppm.min) did not change PC200Mch at any time after exposure. Both a 90-min exposure to 1 ppm ozone and a 30-min exposure to 3 ppm ozone, which are identical in terms of ozone dose (90 ppm.min), decreased PC200Mch to a similar degree. A 120-min exposure to 3 ppm ozone (360 ppm.min) produced a much greater decrease of PC200Mch at 5 min and 5 h after exposure, compared with low-dose exposure. There was a significant correlation between ozone dose and the change in airway responsiveness. In all groups, the baseline sRaw was increased by approximately 50% at 5 min after exposure, but there was no correlation between the changes in PC200Mch and the baseline sRaw. This study suggests that ozone-induced airway hyperresponsiveness in guinea pigs is closely related to ozone dose.

  17. Effects of buthionine sulfoximine on the development of ozone-induced pulmonary fibrosis

    SciTech Connect

    Sun, J.D.; Pickrell, J.A.; Harkema, J.R.; McLaughlin, S.I.; Hahn, F.F.; Henderson, R.F.

    1988-10-01

    The capacity of reduced glutathione (GSH) to protect lung tissue against ozone-induced pulmonary fibrosis was investigated. Male B6C3F1 mice were exposed to 0, 0.2, 0.5, and 1.0 ppm ozone for 23 hr/day for 14 days. During exposures and/or for a period of 90 days after exposures, subgroups of mice at each exposure level were given drinking water containing 30 mM L-buthionine-S,R-sulfoximine (BSO) to lower in vivo levels of GSH. These BSO treatments reduced blood glutamylcysteine synthetase (GCS) activity (regulatory enzyme for GSH biosynthesis) and lung nonprotein sulfhydryl (NPSH) levels in nonexposed animals by approximately half. In contrast, ozone exposures increased blood GCS activity and lung NPSH levels in a concentration-dependent manner, with smaller increases in the BSO-treated mice. Immediately after exposures, an ozone-related inflammatory response was seen in lungs, but no histopathological signs of developing fibrosis were evident. Ninety days later, mice exposed to 1 ppm ozone and not treated with BSO had modest evidence of pulmonary fibrosis. Mice exposed to 1 ppm ozone and treated with BSO during this post-exposure period (regardless of BSO treatment during exposures) showed histopathological evidence of exacerbated pulmonary fibrosis, compared to similarly exposed mice not treated with BSO postexposure. These results indicated that interference with the body's normal defense mechanisms against oxidant damage, including suppression of GSH biosynthesis, exacerbates the subsequent development of pulmonary fibrosis.

  18. Ozone-induced bronchial hyperreactivity in guinea pigs is abolished by BW 755C or FPL 55712 but not by indomethacin

    SciTech Connect

    Lee, H.K.; Murlas, C.

    1985-11-01

    The authors investigated the effects of BW 755C, an inhibitor of both the cyclooxygenase and lipoxygenase pathways of arachidonic acid metabolism; FPL 55712, a selective antagonist of slow-reacting substance of anaphylaxis; and indomethacin, a cyclooxygenase inhibitor, on bronchial reactivity after ozone exposure. Guinea pigs in groups of 5 were treated with BW 755C, FPL 55712, or indomethacin and studied before and 30 min after a 15-min exposure to 3.0 ppm ozone. These animals were compared with a similarly exposed group that was untreated. Reactivity was determined by measuring specific airway resistance (SRaw) upon intravenous acetylcholine infusion in unanesthetized, spontaneously breathing animals. Prior to ozone exposure, they found that drug treatment did not affect either SRaw or muscarinic reactivity. After exposure to 3.0 ppm, all untreated guinea pigs showed substantial muscarinic hyperreactivity. Indomethacin treatment did not inhibit this effect. Furthermore, in the indomethacin-treated animals, marked elevations in SRaw after ozone occurred. In contrast, no change in SRaw or muscarinic reactivity occurred after ozone in any animal treated with either BW 755C or FPL 55712. The authors conclude that ozone-induced bronchial hyperreactivity in the guinea pig rapidly develops after a brief, high-level exposure. This effect may be mediated in part by lipoxygenase products derived from lung arachidonic acid metabolism post-ozone period.

  19. Stabilized epoxygenated fatty acids regulate inflammation, pain, angiogenesis and cancer

    PubMed Central

    Zhang, Guodong; Kodani, Sean; Hammock, Bruce D.

    2014-01-01

    Epoxygenated fatty acids (EpFAs), which are lipid mediators produced by cytochrome P450 epoxygenases from polyunsaturated fatty acids, are important signaling molecules known to regulate various biological processes including inflammation, pain and angiogenesis. The EpFAs are further metabolized by soluble epoxide hydrolase (sEH) to form fatty acid diols which are usually less-active. Pharmacological inhibitors of sEH that stabilize endogenous EpFAs are being considered for human clinical uses. Here we review the biology of ω-3 and ω-6 EpFAs on inflammation, pain, angiogenesis and tumorigenesis. PMID:24345640

  20. Differential regulation of placental amino acid transport by saturated and unsaturated fatty acids.

    PubMed

    Lager, Susanne; Jansson, Thomas; Powell, Theresa L

    2014-10-15

    Fatty acids are critical for normal fetal development but may also influence placental function. We have previously reported that oleic acid (OA) stimulates amino acid transport in primary human trophoblasts (PHTs). In other tissues, saturated and unsaturated fatty acids have distinct effects on cellular signaling, for instance, palmitic acid (PA) but not OA reduces IκBα expression. We hypothesized that saturated and unsaturated fatty acids differentially affect trophoblast amino acid transport and cellular signaling. To test this hypothesis, PHTs were cultured in docosahexaenoic acid (DHA; 50 μM), OA (100 μM), or PA (100 μM). DHA and OA were also combined to test whether DHA could counteract the OA stimulatory effect on amino acid transport. The effects of fatty acids were compared against a vehicle control. Amino acid transport was measured by isotope-labeled tracers. Activation of inflammatory-related signaling pathways and the mechanistic target of rapamycin (mTOR) pathway were determined by Western blot analysis. Exposure of PHTs to DHA for 24 h reduced amino acid transport and phosphorylation of p38 MAPK, STAT3, mTOR, eukaryotic initiation factor 4E-binding protein 1, and ribosomal protein (rp)S6. In contrast, OA increased amino acid transport and phosphorylation of ERK, mTOR, S6 kinase 1, and rpS6. The combination of DHA with OA increased amino acid transport and rpS6 phosphorylation. PA did not affect amino acid transport but reduced IκBα expression. In conclusion, these fatty acids differentially regulated placental amino acid transport and cellular signaling. Taken together, these findings suggest that dietary fatty acids could alter the intrauterine environment by modifying placental function, thereby having long-lasting effects on the developing fetus.

  1. Acute ozone-induced lung injury in rats: Structural-functional relationships of developing alveolar edema

    SciTech Connect

    Paterson, J.F.; Hammond, M.D.; Montgomery, M.R.; Sharp, J.T.; Farrier, S.E.; Balis, J.U. )

    1992-11-01

    As part of a study on the effects of acute ozone stress on the lung surfactant system, we correlated morphometric, biochemical, and functional indices of lung injury using male rats exposed to 3 ppm ozone for 1, 2, 4, and 8 hr. Evaluation of lung mechanics, using the Pulmonary Evaluation and Diagnostic Laboratory System, revealed a significant decrease in dynamic lung compliance (ml/cmH[sub 2]O/kg) from a control value of 0.84 [plus minus] 0.02 (SEM) to 0.72 [plus minus] 0.04 and 0.57 [plus minus] 0.06 at 4 and 8 hr, respectively. At 2 hr there was a transient increase in PaO[sub 2] to 116 torr (control = 92 torr) followed by a decrease at 4 hr (65 torr) and 8 hr (55 torr). Morphometry of lung tissue, fixed by perfusion of fixative via the pulmonary artery at 12 cm H[sub 2]O airway distending pressure, demonstrated an increase in the area of the intravascular compartment at 8 hr, in association with a 65 and 39% replacement of the alveolar area by fluid in ventral and dorsal lung regions, respectively. There was a positive correlation (r = 0.966) between alveolar edema and transudated proteins in lavage fluid. A stepwise multiple regression model, with edema as the dependent variable, suggested that pulmonary vasodilatation, hypoxemia, and depletion of surfactant tubular myelin in lavage fluid were indices for predicting alveolar edema. In a second model, with lavage protein concentration as the dependent variable, decreasing dynamic compliance and hypoxemia were predictors of progressive, intraalveolar transudation of plasma proteins. The above structural-functional relationships support the concept that ozone-induced high-protein alveolar edema is pathogenetically linked to pulmonary hyperemia, deficiency of surfactant tubular myelin, and associated lung dysfunctions.

  2. Regulation of the plasma amino acid profile by leucine via the system L amino acid transporter.

    PubMed

    Zhen, Hongmin; Nakamura, Koichi; Kitaura, Yasuyuki; Kadota, Yoshihiro; Ishikawa, Takuya; Kondo, Yusuke; Xu, Minjun; Shimomura, Yoshiharu

    2015-01-01

    Plasma concentrations of amino acids reflect the intracellular amino acid pool in mammals. However, the regulatory mechanism requires clarification. In this study, we examined the effect of leucine administration on plasma amino acid profiles in mice with and without the treatment of 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) or rapamycin as an inhibitor of system L or mammalian target of rapamycin complex 1, respectively. The elevation of plasma leucine concentration after leucine administration was associated with a significant decrease in the plasma concentrations of isoleucine, valine, methionine, phenylalanine, and tyrosine; BCH treatment almost completely blocked the leucine-induced decrease in plasma amino acid concentrations. Rapamycin treatment had much less effects on the actions of leucine than BCH treatment. These results suggest that leucine regulates the plasma concentrations of branched-chain amino acids, methionine, phenylalanine, and tyrosine, and that system L amino acid transporters are involved in the leucine action.

  3. Regulation of hepatic gene expression by saturated fatty acids

    PubMed Central

    Vallim, T.; Salter, A.M.

    2010-01-01

    Diets rich in saturated fatty acids have long been associated with increased plasma cholesterol concentrations and hence increased risk of cardiovascular disease. More recently, they have also been suggested to promote the development of non-alcoholic fatty liver disease. While there is now considerable evidence to suggest that polyunsaturated fatty acids exert many of their effects through regulating the activity of transcription factors, including peroxisome proliferator activated receptors, sterol regulatory binding proteins (SREBPs) and liver X receptor, our understanding of how saturated fatty acids act is still limited. Here we review the potential mechanisms whereby saturated fatty acids modulate hepatic lipid metabolism thereby impacting on the synthesis, storage and secretion of lipids. Evidence is presented that their effects are, at least partly, mediated through modulation of the activity of the SREBP family of transcription factors. PMID:20227267

  4. Regulation of hepatic gene expression by saturated fatty acids.

    PubMed

    Vallim, T; Salter, A M

    2010-01-01

    Diets rich in saturated fatty acids have long been associated with increased plasma cholesterol concentrations and hence increased risk of cardiovascular disease. More recently, they have also been suggested to promote the development of non-alcoholic fatty liver disease. While there is now considerable evidence to suggest that polyunsaturated fatty acids exert many of their effects through regulating the activity of transcription factors, including peroxisome proliferator activated receptors, sterol regulatory binding proteins (SREBPs) and liver X receptor, our understanding of how saturated fatty acids act is still limited. Here we review the potential mechanisms whereby saturated fatty acids modulate hepatic lipid metabolism thereby impacting on the synthesis, storage and secretion of lipids. Evidence is presented that their effects are, at least partly, mediated through modulation of the activity of the SREBP family of transcription factors.

  5. Cholestenoic acids regulate motor neuron survival via liver X receptors

    PubMed Central

    Theofilopoulos, Spyridon; Griffiths, William J.; Crick, Peter J.; Yang, Shanzheng; Meljon, Anna; Ogundare, Michael; Kitambi, Satish Srinivas; Lockhart, Andrew; Tuschl, Karin; Clayton, Peter T.; Morris, Andrew A.; Martinez, Adelaida; Reddy, M. Ashwin; Martinuzzi, Andrea; Bassi, Maria T.; Honda, Akira; Mizuochi, Tatsuki; Kimura, Akihiko; Nittono, Hiroshi; De Michele, Giuseppe; Carbone, Rosa; Criscuolo, Chiara; Yau, Joyce L.; Seckl, Jonathan R.; Schüle, Rebecca; Schöls, Ludger; Sailer, Andreas W.; Kuhle, Jens; Fraidakis, Matthew J.; Gustafsson, Jan-Åke; Steffensen, Knut R.; Björkhem, Ingemar; Ernfors, Patrik; Sjövall, Jan; Arenas, Ernest; Wang, Yuqin

    2014-01-01

    Cholestenoic acids are formed as intermediates in metabolism of cholesterol to bile acids, and the biosynthetic enzymes that generate cholestenoic acids are expressed in the mammalian CNS. Here, we evaluated the cholestenoic acid profile of mammalian cerebrospinal fluid (CSF) and determined that specific cholestenoic acids activate the liver X receptors (LXRs), enhance islet-1 expression in zebrafish, and increase the number of oculomotor neurons in the developing mouse in vitro and in vivo. While 3β,7α-dihydroxycholest-5-en-26-oic acid (3β,7α-diHCA) promoted motor neuron survival in an LXR-dependent manner, 3β-hydroxy-7-oxocholest-5-en-26-oic acid (3βH,7O-CA) promoted maturation of precursors into islet-1+ cells. Unlike 3β,7α-diHCA and 3βH,7O-CA, 3β-hydroxycholest-5-en-26-oic acid (3β-HCA) caused motor neuron cell loss in mice. Mutations in CYP7B1 or CYP27A1, which encode enzymes involved in cholestenoic acid metabolism, result in different neurological diseases, hereditary spastic paresis type 5 (SPG5) and cerebrotendinous xanthomatosis (CTX), respectively. SPG5 is characterized by spastic paresis, and similar symptoms may occur in CTX. Analysis of CSF and plasma from patients with SPG5 revealed an excess of the toxic LXR ligand, 3β-HCA, while patients with CTX and SPG5 exhibited low levels of the survival-promoting LXR ligand 3β,7α-diHCA. Moreover, 3β,7α-diHCA prevented the loss of motor neurons induced by 3β-HCA in the developing mouse midbrain in vivo.Our results indicate that specific cholestenoic acids selectively work on motor neurons, via LXR, to regulate the balance between survival and death. PMID:25271621

  6. Fatty acids are potential endogenous regulators of aldosterone secretion.

    PubMed

    Goodfriend, T L; Ball, D L; Elliott, M E; Morrison, A R; Evenson, M A

    1991-05-01

    Adrenal glomerulosa cells washed with delipidated albumin produced increased amounts of aldosterone in response to angiotensin-II (AII) or (Bu)2cAMP. Albumin treatment also increased binding of 125I-labeled AII to high affinity binding sites on adrenal cells. Lipid extracts of albumin solutions that were used to wash cells inhibited AII binding and aldosterone responses by washed glomerulosa cells. Chromatographic fractionation and mass spectroscopic analysis indicated that the inhibitors removed from cells by albumin were long chain fatty acids. Exogenous fatty acids not only inhibited AII binding, but they inhibited basal aldosterone production and increments in aldosterone caused by AII or dbcAMP, suggesting an effect on postreceptor steps in aldosteronogenesis. The most potent and most abundant fatty acids removed from adrenal cells were oleic, linoleic, and arachidonic. These fatty acids inhibited at micromolar concentrations in the absence of albumin and at somewhat higher concentrations in its presence. Cells that had been washed, then inhibited by exogenous oleic acid in vitro, were restored to their enhanced responsiveness by a second albumin wash, making it unlikely that cell damage is the mechanism of inhibition by fatty acids. Responses of fasciculata cells were not potentiated by albumin washes, and cortisol production was less sensitive than aldosterone production to exogenous fatty acids. Binding of ANP to glomerulosa cells was not affected by albumin or fatty acids. These results combined with clinical correlations make it plausible that unesterified fatty acids are naturally occurring regulators of the adrenal glomerulosa. Insulin's ability to lower plasma levels of fatty acids may be one way that it causes sodium retention.

  7. Fatty acids regulation of inflammatory and metabolic genes.

    PubMed

    Masi, Laureane N; Rodrigues, Alice C; Curi, Rui

    2013-07-01

    Fatty acids influence human health and diseases in various ways. In recent years, much work has been carried out to elucidate the mechanisms by which dietary fatty acids control short-term and long-term cellular functions. We have reviewed herein the most recent studies on modulation of gene expression by fatty acids. A number of genes respond to transcription factors and present a transcription factor response element in their promoter regions. Fatty acids may exert their effects on metabolism by regulating gene transcription via transcription factors. Understanding how fatty acids control expression of metabolic genes is a promising strategy to be investigated by aiming to treat metabolic diseases such as insulin resistance, obesity, and type 2 diabetes mellitus. Fatty acids exert many of their biological effects through the modulation of the activity of transcription factors, such as sterol regulatory element-binding proteins, peroxisome proliferator-activated receptors, and liver X receptors. Fatty acid action through transcription factors controls the expression of several inflammatory and metabolic genes.

  8. Central regulation of gastric acid secretion: the role of neuropeptides.

    PubMed

    Morley, J E; Levine, A S; Silvis, S E

    1982-08-02

    A variety of stimuli can act through the central nervous system to alter gastric acid secretion. Lesioning and stimulation experiments have established roles for the lateral and ventromedial hypothalamus and the limbic system in the central regulation of gastric acid secretion. Recently a number of neuropeptides have been demonstrated to alter gastric acid secretion after central administration. Thyrotropin-releasing hormone (TRH) and gastrin both increase gastric acid secretion, whereas bombesin, calcitonin, the endogenous opioid peptides and neurotensin decrease gastric acid secretion. With the exception of bombesin, all the other neuropeptides appear to produce their effects through a vagally mediated mechanism. In addition, a number of these neuropeptides, when centrally administered, have been demonstrated to exert a potent cytoprotective effect against stress ulcer development. This review develops a peptidergic hypothesis of gastric acid secretion, suggesting that the final integration of the cephalic phase of gastric acid secretion is brought about by maintaining a delicate balance in the concentration of a number of interacting peptides and monoamines.

  9. Ethylene Insensitivity Modulates Ozone-Induced Cell Death in Birch1

    PubMed Central

    Vahala, Jorma; Ruonala, Raili; Keinänen, Markku; Tuominen, Hannele; Kangasjärvi, Jaakko

    2003-01-01

    We have used genotypic variation in birch (Betula pendula Roth) to investigate the roles of ozone (O3)-induced ethylene (ET), jasmonic acid, and salicylic acid in the regulation of tissue tolerance to O3. Of these hormones, ET evolution correlated best with O3-induced cell death. Disruption of ET perception by transformation of birch with the dominant negative mutant allele etr1-1 of the Arabidopsis ET receptor gene ETR1 or blocking of ET perception with 1-methylcyclopropene reduced but did not completely prevent the O3-induced cell death, when inhibition of ET biosynthesis with aminooxyacetic acid completely abolished O3 lesion formation. This suggests the presence of an ET-signaling-independent but ET biosynthesis-dependent component in the ET-mediated stimulation of cell death in O3-exposed birch. Functional ET signaling was required for the O3 induction of the gene encoding β-cyanoalanine synthase, which catalyzes detoxification of the cyanide formed during ET biosynthesis. The results suggest that functional ET signaling is required to protect birch from the O3-induced cell death and that a decrease in ET sensitivity together with a simultaneous, high ET biosynthesis can potentially cause cell death through a deficient detoxification of cyanide. PMID:12746524

  10. Variability in ozone-induced pulmonary injury and inflammation in healthy and cardiovascular-compromised rat models.

    PubMed

    Kodavanti, Urmila P; Ledbetter, Allen D; Thomas, Ronald F; Richards, Judy E; Ward, William O; Schladweiler, Mette C; Costa, Daniel L

    2015-01-01

    The molecular bases for variability in air pollutant-induced pulmonary injury due to underlying cardiovascular (CVD) and/or metabolic diseases are unknown. We hypothesized that healthy and genetic CVD-prone rat models will exhibit exacerbated response to acute ozone exposure dependent on the type and severity of disease. Healthy male 12-14-week-old Wistar Kyoto (WKY), Wistar (WS) and Sprague Dawley (SD); and CVD-compromised spontaneously hypertensive (SH), Fawn-Hooded hypertensive (FHH), stroke-prone spontaneously hypertensive (SHSP), obese spontaneously hypertensive heart failure (SHHF) and obese JCR (JCR) rats were exposed to 0.0, 0.25, 0.5, or 1.0 ppm ozone for 4 h; pulmonary injury and inflammation were analyzed immediately following (0-h) or 20-h later. Baseline bronchoalveolar lavage fluid (BALF) protein was higher in CVD strains except for FHH when compared to healthy. Ozone-induced increases in protein and inflammation were concentration-dependent within each strain but the degree of response varied from strain to strain and with time. Among healthy rats, SD were least affected. Among CVD strains, lean rats were more susceptible to protein leakage from ozone than obese rats. Ozone caused least neutrophilic inflammation in SH and SHHF while SHSP and FHH were most affected. BALF neutrophils and protein were poorly correlated when considering the entire dataset (r = 0.55). The baseline and ozone-induced increases in cytokine mRNA varied markedly between strains and did not correlate with inflammation. These data illustrate that the degree of ozone-induced lung injury/inflammation response is likely influenced by both genetic and physiological factors that govern the nature of cardiovascular compromise in CVD models.

  11. Effect of Obesity on Acute Ozone-Induced Changes in Airway Function, Reactivity, and Inflammation in Adult Females

    PubMed Central

    Bennett, William D.; Ivins, Sally; Alexis, Neil E.; Wu, Jihong; Bromberg, Philip A.; Brar, Sukhdev S.; Travlos, Gregory; London, Stephanie J.

    2016-01-01

    We previously observed greater ozone-induced lung function decrements in obese than non-obese women. Animal models suggest that obesity enhances ozone-induced airway reactivity and inflammation. In a controlled exposure study, we compared the acute effect of randomized 0.4ppm ozone and air exposures (2 h with intermittent light exercise) in obese (N = 20) (30ozone-induced increases in sputum neutrophils. Plasma IL-6 was increased by exercise (4 hr post air exposure vs. pre) only in the obese but returned to pre-air exposure levels at 20hr post-exposure. Plasma IL-6 was significantly increased at 4hr post ozone exposure in both groups and returned to pre-exposure levels by 20h post-exposure. These results confirm our previous findings of greater post-ozone spirometric decrements in obese young women. However, acute ozone-induced airway reactivity to methacholine and airway inflammation did not differ by obesity at the exposure and exercise levels used. PMID:27513854

  12. Effect of Obesity on Acute Ozone-Induced Changes in Airway Function, Reactivity, and Inflammation in Adult Females.

    PubMed

    Bennett, William D; Ivins, Sally; Alexis, Neil E; Wu, Jihong; Bromberg, Philip A; Brar, Sukhdev S; Travlos, Gregory; London, Stephanie J

    2016-01-01

    We previously observed greater ozone-induced lung function decrements in obese than non-obese women. Animal models suggest that obesity enhances ozone-induced airway reactivity and inflammation. In a controlled exposure study, we compared the acute effect of randomized 0.4ppm ozone and air exposures (2 h with intermittent light exercise) in obese (N = 20) (30ozone-induced increases in sputum neutrophils. Plasma IL-6 was increased by exercise (4 hr post air exposure vs. pre) only in the obese but returned to pre-air exposure levels at 20hr post-exposure. Plasma IL-6 was significantly increased at 4hr post ozone exposure in both groups and returned to pre-exposure levels by 20h post-exposure. These results confirm our previous findings of greater post-ozone spirometric decrements in obese young women. However, acute ozone-induced airway reactivity to methacholine and airway inflammation did not differ by obesity at the exposure and exercise levels used.

  13. Amino acids regulate the intracellular trafficking of the general amino acid permease of Saccharomycescerevisiae.

    PubMed

    Chen, Esther J; Kaiser, Chris A

    2002-11-12

    The delivery to the plasma membrane of the general amino acid permease, Gap1p, of Saccharomyces cerevisiae is regulated by the quality of the nitrogen source in the growth medium. In an effort to define how different nitrogen sources control Gap1p sorting, we find that mutations in GDH1 and GLN1 that decrease the flux through the glutamate and glutamine synthesis pathways result in increased Gap1p sorting to the plasma membrane. Conversely, deletion of MKS1, which increases glutamate and glutamine synthesis, decreases Gap1p sorting to the plasma membrane. Glutamate and glutamine are not unusual in their ability to regulate Gap1p sorting, because the addition of all natural amino acids and many amino acid analogs to the growth medium results in increased Gap1p sorting to the vacuole. Importantly, amino acids have the capacity to signal Gap1p sorting to the vacuole regardless of whether they can be used as a source of nitrogen. Finally, we show that rapamycin does not affect Gap1p sorting, indicating that Gap1p sorting is not directly influenced by the TOR pathway. Together, these data show that amino acids are a signal for sorting Gap1p to the vacuole and imply that the nitrogen-regulated Gap1p sorting machinery responds to amino acid-like compounds rather than to the overall nutritional status associated with growth on a particular nitrogen source.

  14. Acid rain compliance: Coordination of state and federal regulation

    SciTech Connect

    Nordhaus, R.R.

    1992-01-01

    The Clean Air Act (CAA) Amendments of 1990 impose new controls on emissions by electric utilities of the two major precursors of acid rain: sulfur dioxide (SO2) and oxides of nitrogen (NOx). Utilities, and the utility holding company systems and power pools of which they are members, will be subject to extensive and costly compliance obligations under the new statute. Most of these utilities, utility systems, and power pools are regulated by more than one utility regulatory authority. Some utilities are regulated by several states, some by a single state and by the Federal Energy Regulatory Commission (FERC), and some by multiple states, by the FERC, and by the Securities and Exchange Commission (SEC). Utility regulators will need to coordinate their policies for ratemaking and for reviewing acid rain compliance strategies if least cost solutions are to be implemented without imposing on ratepayers and utility shareholders the costs and risks of inconsistent regulatory determinations. This article outlines the scope of the coordination problem and addresses possible approaches that utility regulators may take to deal with this problem.

  15. Nucleic acid modifications in regulation of gene expression

    PubMed Central

    Chen, Kai; Zhao, Boxuan Simen; He, Chuan

    2016-01-01

    Nucleic acids carry a wide range of different chemical modifications. In contrast to previous views that these modifications are static and only play fine-tuning functions, recent research advances paint a much more dynamic picture. Nucleic acids carry diverse modifications and employ these chemical marks to exert essential or critical influences in a variety of cellular processes in eukaryotic organisms. This review covers several nucleic acid modifications that play important regulatory roles in biological systems, especially in regulation of gene expression: 5-methylcytosine (5mC) and its oxidative derivatives, and N6 -methyladenine (6mA) in DNA; N6 -methyladenosine (m6A), pseudouridine (), and 5-methylcytosine (m5C) in messenger RNA and long non-coding RNA. Modifications in other non-coding RNAs, such as tRNA, miRNA, and snRNA, are also briefly summarized. We provide brief historical perspective of the field, and highlight recent progress in identifying diverse nucleic acid modifications and exploring their functions in different organisms. Overall, we believe that work in this field will yield additional layers of both chemical and biological complexity as we continue to uncover functional consequences of known nucleic acid modifications and discover new ones. PMID:26933737

  16. Nucleic Acid Modifications in Regulation of Gene Expression.

    PubMed

    Chen, Kai; Zhao, Boxuan Simen; He, Chuan

    2016-01-21

    Nucleic acids carry a wide range of different chemical modifications. In contrast to previous views that these modifications are static and only play fine-tuning functions, recent research advances paint a much more dynamic picture. Nucleic acids carry diverse modifications and employ these chemical marks to exert essential or critical influences in a variety of cellular processes in eukaryotic organisms. This review covers several nucleic acid modifications that play important regulatory roles in biological systems, especially in regulation of gene expression: 5-methylcytosine (5mC) and its oxidative derivatives, and N(6)-methyladenine (6mA) in DNA; N(6)-methyladenosine (m(6)A), pseudouridine (Ψ), and 5-methylcytidine (m(5)C) in mRNA and long non-coding RNA. Modifications in other non-coding RNAs, such as tRNA, miRNA, and snRNA, are also briefly summarized. We provide brief historical perspective of the field, and highlight recent progress in identifying diverse nucleic acid modifications and exploring their functions in different organisms. Overall, we believe that work in this field will yield additional layers of both chemical and biological complexity as we continue to uncover functional consequences of known nucleic acid modifications and discover new ones. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Ozone-induced loss of neuronal M{sub 2} muscarinic receptor function is prevented by cyclophosphamide

    SciTech Connect

    Gambone, L.M.; Elbon, C.L.; Fryer, A.D.

    1994-09-01

    The authors tested the hypothesis that inflammatory cells mediate the loss of neuronal M{sub 2} muscarinic receptors in the lung after ozone exposure. Pathogen-free guinea pigs treated with cyclophosphamide (30 mg {center_dot} kg{sup {minus}1} {center_dot} day{sup {minus}1} ip for 7 days) before exposure to ozone were compared with untreated ozone-exposed animals. This dose of cyclophosphamide significantly reduced leukocytes in peripheral blood and bronchoalveolar lavage fluid. Twenty-four hours after ozone, muscarinic receptor function was tested in anesthetized animals. In air-exposed guinea pigs, vagally induced bronchoconstriction was attenuated by the muscarinic agonist pilocarpine (0.1-100 {mu}g/kg iv) and potentiated by the selective M{sub 2} antagonist gallamine (0.1-10 mg/kg iv), indicating that the neuronal M{sub 2} muscarinic receptors were functioning. These responses were significantly reduced after ozone, indicating loss of neuronal M{sub 2} muscarinic receptor function. However, in those animals treated with cyclophosphamide, M{sub 2} muscarinic receptor function was not altered by ozone. These data suggest that ozone-induced loss of neuronal muscarinic receptor function is mediated via inflammatory cells and that the link between ozone-induced hyperresponsiveness and inflammation may be the neuronal M{sub 2} muscarinic receptor. 27 refs., 9 figs.

  18. Glutathione deficient C57BL/6J mice are not sensitized to ozone-induced lung injury.

    PubMed

    Johansson, Elisabet; Wesselkamper, Scott C; Shertzer, Howard G; Leikauf, George D; Dalton, Timothy P; Chen, Ying

    2010-05-28

    In this study we examined the role of the antioxidant glutathione (GSH) in pulmonary susceptibility to ozone toxicity, utilizing GSH deficient C57BL/6J mice that lack the expression of glutamate-cysteine ligase modifier subunit (GCLM). Gclm(-/-) knockout mice had 70% GSH depletion in the lung. Gclm(+/+) wild-type and Gclm(-/-) mice were exposed to either 0.3 ppm ozone or filtered air for 48h. Ozone-induced lung hyperpermeability, as measured by total protein concentration in bronchoalveolar lavage fluid, was surprisingly lower in Gclm(-/-) mice than in wild-type mice. Lung hyperpermeability did not correlate with the degree of neutrophilia or with inflammatory gene expression. Pulmonary antioxidant response to ozone, assessed by increased mRNA levels of metallothionein 1 and 2, alpha-tocopherol transporter protein, and solute carrier family 23 member 2 (sodium-dependent vitamin C transporter) was greater in Gclm(-/-) mice than in Gclm(+/+) mice. These results suggest that compensatory augmentation of antioxidant defenses in Gclm(-/-) mice may confer increased resistance to ozone-induced lung injury.

  19. Vitamin E antagonizes ozone-induced asthma exacerbation in Balb/c mice through the Nrf2 pathway.

    PubMed

    Duan, Liju; Li, Jinquan; Ma, Ping; Yang, Xu; Xu, Shunqing

    2017-09-01

    Millions of people are regularly exposed to ozone, a gas known to contribute significantly to worsening the symptoms of patients with asthma. However, the mechanisms underlying these ozone exacerbation effects are not fully understood. In this study, we examined the exacerbation effect of ozone in OVA-induced asthma mice and tried to demonstrate the protective mechanism of vitamin E (VE). An asthma mouse model was established, and used to identify the exacerbating effects of ozone by assessing cytokine and serum immunoglobulin concentrations, airway leukocyte infiltration, histopathological changes in lung tissues, and airway hyper-responsiveness. We then determined the amount of reactive oxygen species (ROS) accumulated, the extent to which VE induced ROS elimination, and examined the antagonistic effects of VE on the ozone-induced exacerbating effects. This study showed that 1-ppm ozone exposure could exacerbate OVA-induced asthma in mice. More importantly we found that ozone induced oxidative stress in asthmatic airways may lead to the inhibition of Nuclear factor-erythroid 2-related factor 2 (Nrf2), and may subsequently induce even more exaggerated oxidative stress associated with asthma exacerbation. Through VE induced Nrf2 activation and the subsequent increase in Nrf2 target protein expression, this study suggests a novel mechanism for alleviating ozone exacerbated asthma symptoms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The bile acid sensor FXR regulates insulin transcription and secretion.

    PubMed

    Renga, Barbara; Mencarelli, Andrea; Vavassori, Piero; Brancaleone, Vincenzo; Fiorucci, Stefano

    2010-03-01

    Farnesoid X Receptor plays an important role in maintaining bile acid, cholesterol homeostasis and glucose metabolism. Here we investigated whether FXR is expressed by pancreatic beta-cells and regulates insulin signaling in pancreatic beta-cell line and human islets. We found that FXR activation induces positive regulatory effects on glucose-induced insulin transcription and secretion by genomic and non-genomic activities. Genomic effects of FXR activation relay on the induction of the glucose regulated transcription factor KLF11. Indeed, results from silencing experiments of KLF11 demonstrate that this transcription factor is essential for FXR activity on glucose-induced insulin gene transcription. In addition FXR regulates insulin secretion by non-genomic effects. Thus, activation of FXR in betaTC6 cells increases Akt phosphorylation and translocation of the glucose transporter GLUT2 at plasma membrane, increasing the glucose uptake by these cells. In vivo experiments on Non Obese Diabetic (NOD) mice demonstrated that FXR activation delays development of signs of diabetes, hyperglycemia and glycosuria, by enhancing insulin secretion and by stimulating glucose uptake by the liver. These data established that an FXR-KLF11 regulated pathway has an essential role in the regulation of insulin transcription and secretion induced by glucose.

  1. Cyclic phosphatidic acid and lysophosphatidic acid induce hyaluronic acid synthesis via CREB transcription factor regulation in human skin fibroblasts.

    PubMed

    Maeda-Sano, Katsura; Gotoh, Mari; Morohoshi, Toshiro; Someya, Takao; Murofushi, Hiromu; Murakami-Murofushi, Kimiko

    2014-09-01

    Cyclic phosphatidic acid (cPA) is a naturally occurring phospholipid mediator and an analog of the growth factor-like phospholipid lysophosphatidic acid (LPA). cPA has a unique cyclic phosphate ring at the sn-2 and sn-3 positions of its glycerol backbone. We showed before that a metabolically stabilized cPA derivative, 2-carba-cPA, relieved osteoarthritis pathogenesis in vivo and induced hyaluronic acid synthesis in human osteoarthritis synoviocytes in vitro. This study focused on hyaluronic acid synthesis in human fibroblasts, which retain moisture and maintain health in the dermis. We investigated the effects of cPA and LPA on hyaluronic acid synthesis in human fibroblasts (NB1RGB cells). Using particle exclusion and enzyme-linked immunosorbent assays, we found that both cPA and LPA dose-dependently induced hyaluronic acid synthesis. We revealed that the expression of hyaluronan synthase 2 messenger RNA and protein is up-regulated by cPA and LPA treatment time dependently. We then characterized the signaling pathways up-regulating hyaluronic acid synthesis mediated by cPA and LPA in NB1RGB cells. Pharmacological inhibition and reporter gene assays revealed that the activation of the LPA receptor LPAR1, Gi/o protein, phosphatidylinositol-3 kinase (PI3K), extracellular-signal-regulated kinase (ERK), and cyclic adenosine monophosphate response element-binding protein (CREB) but not nuclear factor κB induced hyaluronic acid synthesis by the treatment with cPA and LPA in NB1RGB cells. These results demonstrate for the first time that cPA and LPA induce hyaluronic acid synthesis in human skin fibroblasts mainly through the activation of LPAR1-Gi/o followed by the PI3K, ERK, and CREB signaling pathway. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Transcriptional regulation of muscle fatty acid-binding protein.

    PubMed

    Carey, J O; Neufer, P D; Farrar, R P; Veerkamp, J H; Dohm, G L

    1994-03-15

    Heart fatty acid-binding protein (H-FABP) is present in a wide variety of tissues but is found in the highest concentration in cardiac and red skeletal muscle. It has been proposed that the expression of H-FABP correlates directly with the fatty acid-oxidative capacity of the tissue. In the present study, the expression of H-FABP was measured in red and white skeletal muscle under two conditions in which fatty acid utilization is known to be increased: streptozotocin-induced diabetes and fasting. Protein concentration, mRNA concentration and transcription rate were measured under both conditions. The level of both protein and mRNA increased approximately 2-fold under each condition. The transcription rate was higher in red skeletal muscle than in white muscle, was increased 2-fold during fasting, but was unchanged by streptozotocin-induced diabetes. In addition to supporting the hypothesis that H-FABP is induced during conditions of increased fatty acid utilization, these findings demonstrate that the regulation of H-FABP expression may or may not be at the level of transcription depending on the stimulus.

  3. Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

    PubMed

    Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

    2016-07-01

    Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. © 2016 Federation of European Biochemical Societies.

  4. Ozone Induced Impairment of Systemic Metabolic Processes: Influence of Prior Ozone Exposure and Metformin Pre-treatment on Aged Wistar Kyoto (WKY) Rats.

    EPA Science Inventory

    SOT2014 Abstract for presentation: March 23-27, 2014; Phoenix, AZ Ozone Induced Impairment of Systemic Metabolic Processes: Influence of Prior Ozone Exposure and Metformin Pre-treatment on Aged Wistar Kyoto (WKY) Rats. V. Bass, D. Andrews, J. Richards, M. Schladweiler, A. Ledb...

  5. Ozone Induced Impairment of Systemic Metabolic Processes: Influence of Prior Ozone Exposure and Metformin Pre-treatment on Aged Wistar Kyoto (WKY) Rats.

    EPA Science Inventory

    SOT2014 Abstract for presentation: March 23-27, 2014; Phoenix, AZ Ozone Induced Impairment of Systemic Metabolic Processes: Influence of Prior Ozone Exposure and Metformin Pre-treatment on Aged Wistar Kyoto (WKY) Rats. V. Bass, D. Andrews, J. Richards, M. Schladweiler, A. Ledb...

  6. Ozone-Induced Responses in Croton floribundus Spreng. (Euphorbiaceae): Metabolic Cross-Talk between Volatile Organic Compounds and Calcium Oxalate Crystal Formation

    PubMed Central

    Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3. PMID:25165889

  7. Ozone-induced responses in Croton floribundus Spreng. (Euphorbiaceae): metabolic cross-talk between volatile organic compounds and calcium oxalate crystal formation.

    PubMed

    Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3.

  8. Biotin and Lipoic Acid: Synthesis, Attachment and Regulation

    PubMed Central

    Cronan, John E.

    2014-01-01

    Summary Two vitamins, biotin and lipoic acid, are essential in all three domains of life. Both coenzymes function only when covalently attached to key metabolic enzymes. There they act as “swinging arms” that shuttle intermediates between two active sites (= covalent substrate channeling) of key metabolic enzymes. Although biotin was discovered over 100 years ago and lipoic acid 60 years ago, it was not known how either coenzyme is made until recently. In Escherichia coli the synthetic pathways for both coenzymes have now been worked out for the first time. The late steps of biotin synthesis, those involved in assembling the fused rings, were well-described biochemically years ago, although recent progress has been made on the BioB reaction, the last step of the pathway in which the biotin sulfur moiety is inserted. In contrast, the early steps of biotin synthesis, assembly of the fatty acid-like “arm” of biotin were unknown. It has now been demonstrated that the arm is made by using disguised substrates to gain entry into the fatty acid synthesis pathway followed by removal of the disguise when the proper chain length is attained. The BioC methyltransferase is responsible for introducing the disguise and the BioH esterase for its removal. In contrast to biotin, which is attached to its cognate proteins as a finished molecule, lipoic acid is assembled on its cognate proteins. An octanoyl moiety is transferred from the octanoyl-ACP of fatty acid synthesis to a specific lysine residue of a cognate protein by the LipB octanoyl transferase followed by sulfur insertion at carbons C6 and C8 by the LipA lipoyl synthetase. Assembly on the cognate proteins regulates the amount of lipoic acid synthesized and thus there is no transcriptional control of the synthetic genes. In contrast transcriptional control of the biotin synthetic genes is wielded by a remarkably sophisticated, yet simple, system, exerted through BirA a dual function protein that both represses

  9. Regulation of hepatic bile acid transporters Ntcp and Bsep expression

    PubMed Central

    Cheng, Xingguo; Buckley, David; Klaassen, Curtis D.

    2009-01-01

    Sodium-taurocholate cotransporting polypeptide (Ntcp) and bile salt export pump (Bsep) are two key transporters for hepatic bile acid uptake and excretion. Alterations in Ntcp and Bsep expression have been reported in pathophysiological conditions. In the present study, the effects of age, gender, and various chemicals on the regulation of these two transporters were characterized in mice. Ntcp and Bsep mRNA levels in mouse liver were low in the fetus, but increased to its highest expression at parturition. After birth, mouse Ntcp and Bsep mRNA decreased by more than 50%, and then gradually increased to adult levels by day 30. Expression of mouse Ntcp mRNA and protein exhibit higher levels in female than male livers, which is consistent with the trend of human NTCP mRNA expression between men and women. No gender difference exists in BSEP/Bsep expression in human and mouse livers. Hormone replacements conducted in gonadectomized, hypophysectomized, and lit/lit mice indicate that female-predominant Ntcp expression in mouse liver is due to the inhibitory effect of male-pattern GH secretion, but not sex hormones. Ntcp and Bsep expression are in general resistant to induction by a large battery of microsomal enzyme inducers. Administration of cholestyramine increased Ntcp, whereas chenodeoxycholic acid increased Bsep mRNA expression. In silico analysis indicates that female-predominant mouse and human Ntcp/NTCP expression may be due to GH. In conclusion, mouse Ntcp and Bsep are regulated by age, gender, cholestyramine, and bile acid, but resistant to induction by most microsomal enzyme inducers. PMID:17897632

  10. Metabolic regulation of amino acid uptake in marine waters

    SciTech Connect

    Kirchman, D.L.; Hodson, R.E.

    1986-03-01

    To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.

  11. Systemic regulation of soybean nodulation by acidic growth conditions.

    PubMed

    Lin, Meng-Han; Gresshoff, Peter M; Ferguson, Brett J

    2012-12-01

    Mechanisms inhibiting legume nodulation by low soil pH, although highly prevalent and economically significant, are poorly understood. We addressed this in soybean (Glycine max) using a combination of physiological and genetic approaches. Split-root and grafting studies using an autoregulation-of-nodulation-deficient mutant line, altered in the autoregulation-of-nodulation receptor kinase GmNARK, determined that a systemic, shoot-controlled, and GmNARK-dependent mechanism was critical for facilitating the inhibitory effect. Acid inhibition was independent of aluminum ion concentration and occurred early in nodule development, between 12 and 96 h post inoculation with Bradyrhizobium japonicum. Biological effects were confirmed by measuring transcript numbers of known early nodulation genes. Transcripts decreased on both sides of split-root systems, where only one side was subjected to low-pH conditions. Our findings enhance the present understanding of the innate mechanisms regulating legume nodulation control under acidic conditions, which could benefit future attempts in agriculture to improve nodule development and biological nitrogen fixation in acid-stressed soils.

  12. Seasonal development of ozone-induced foliar injury on tall milkweed (Asclepias exaltata) in Great Smoky Mountains National Park.

    PubMed

    Souza, Lara; Neufeld, Howard S; Chappelka, Arthur H; Burkey, Kent O; Davison, Alan W

    2006-05-01

    The goals of this study were to document the development of ozone-induced foliar injury, on a leaf-by-leaf basis, and to develop ozone exposure relationships for leaf cohorts and individual tall milkweeds (Asclepias exaltata L.) in Great Smoky Mountains National Park. Plants were classified as either ozone-sensitive or insensitive based on the amount of foliar injury. Sensitive plants developed injury earlier in the season and to a greater extent than insensitive plants. Older leaf cohorts were more likely to belong to high injury classes by the end of each of the two growing seasons. In addition, leaf loss was more likely for older cohorts (2000) and lower leaf positions (2001) than younger cohorts and upper leaves, respectively. Most leaves abscised without prior ozone-like stippling or chlorosis. Failure to take this into account can result in underestimation of the effects of ozone on these plants.

  13. Human nutrigenomics of gene regulation by dietary fatty acids.

    PubMed

    Afman, Lydia A; Müller, Michael

    2012-01-01

    Nutrigenomics employs high-throughput genomics technologies to unravel how nutrients modulate gene and protein expression and ultimately influence cellular and organism metabolism. The most often-applied genomics technique so far is transcriptomics, which allows quantifying genome-wide changes in gene expression of thousands of genes at the same time in one sample. The performance of gene expression quantification requires sufficient high-quality homogenous cellular material, therefore research in healthy volunteers is restricted to biopsies from easy accessible tissues such as subcutaneous adipose tissue, skeletal muscle and intestinal biopsies or even more easily accessible cells such as peripheral blood mononuclear cells from blood. There is now significant evidence that fatty acids, in particular unsaturated fatty acids, exert many of their effects through modulation of gene transcription by regulating the activity of numerous transcription factors, including nuclear receptors such as peroxisome proliferator activated receptors, liver X receptor and sterol regulatory binding proteins. This review evaluates the human nutrigenomics studies performed on dietary fat since the initiation of nutrigenomics research around 10 years ago. Although the number of studies is still limited, all studies clearly suggest that changes in dietary fatty acids intake and composition can have a significant impact on cellular adaptive response capacity by gene transcription changes in humans. This adds important knowledge to our understanding of the strong effects that various fatty acids can have on numerous metabolic and inflammatory pathways, signaling routes and homeostatic control in the cell and ultimately on whole body health. It is important to use and integrate nutrigenomics in all future nutrition studies to build up the necessary framework for evidence-based nutrition in near future. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Role of neutralizing anti-murine interleukin-17A monoclonal antibody on chronic ozone-induced airway inflammation in mice.

    PubMed

    Zhang, Min; Fei, Xia; Zhang, Guo-Qing; Zhang, Peng-Yu; Li, Feng; Bao, Wu-Ping; Zhang, Ying-Ying; Zhou, Xin

    2016-10-01

    Exposure to ozone has led to airway inflammation and airway hyperresponsiveness, which potential mechanisms relate to ozone-induced oxidative stress. IL-17 is a growing target for autoimmune and inflammatory diseases. The aim of the study was to examine the inhibitory effects of anti-murine interleukin-17A monoclonal antibody (IL-17mAb) on adverse effects of ozone which are noted above. After C57/BL6 mice were exposed to ozone (2.5ppm; 3h) for 12 times over 6 weeks, IL-17mAb, PBS was intraperitoneally injected into mice 1h after ozone or air exposure for 6 weeks and mice were studied 24h after final exposure, monitoring bronchial responsiveness, airway inflammatory cells, lung histology, levels of neutrophil-related chemokine and proinflammatory cytokines in bronchoalveolar lavage (BAL) fluid and serum, the expression of IL-17A mRNA and protein, glucocorticoid receptors (GR), and the phosphorylation of p38MAPK in lung tissues. The administration of IL-17mAb reduced the ozone-induced increases in total cells, especially neutrophils; decreased levels of cytokines, including IL-8 in BAL fluid, IL-8 and IL-17A in serum; mitigated the severity of airway hyperresponsiveness; attenuated lung inflammation scores and histologic analysis confirmed the suppression of lung inflammation, compared with the administration of a control PBS. Exposure to ozone results in increases in IL-17A production rate, mRNA and protein levels of IL-17A and the protein level of GR. These effects were halted and reversed by IL-17mAb treatment. Furthermore, IL-17mAb also reduced the phosphorylation of p38MAPK. Therefore, we conclude that IL-17mAb may be a useful therapy in ozone-related diseases, including COPD.

  15. Ozone-induced airway epithelial cell death, the neurokinin-1 receptor pathway, and the postnatal developing lung

    PubMed Central

    Murphy, Shannon R.; Oslund, Karen L.; Hyde, Dallas M.; Miller, Lisa A.; Van Winkle, Laura S.

    2014-01-01

    Children are uniquely susceptible to ozone because airway and lung growth continue for an extensive period after birth. Early-life exposure of the rhesus monkey to repeated ozone cycles results in region-specific disrupted airway/lung growth, but the mediators and mechanisms are poorly understood. Substance P (SP), neurokinin-1 receptor (NK-1R); and nuclear receptor Nur77 (NR4A1) are signaling pathway components involved in ozone-induced cell death. We hypothesize that acute ozone (AO) exposure during postnatal airway development disrupts SP/NK-1R/Nur77 pathway expression and that these changes correlate with increased ozone-induced cell death. Our objectives were to 1) spatially define the normal development of the SP/NK-1R/Nur77 pathway in conducting airways; 2) compare how postnatal age modulates responses to AO exposure; and 3) determine how concomitant, episodic ozone exposure modifies age-specific acute responses. Male infant rhesus monkeys were assigned at age 1 mo to two age groups, 2 or 6 mo, and then to one of three exposure subgroups: filtered air (FA), FA+AO (AO: 8 h/day × 2 days), or episodic biweekly ozone exposure cycles (EAO: 8 h/day × 5 days/14-day cycle+AO). O3 = 0.5 ppm. We found that 1) ozone increases SP/NK-1R/Nur77 pathway expression in conducting airways, 2) an ozone exposure cycle (5 days/cycle) delivered early at age 2 mo resulted in an airway that was hypersensitive to AO exposure at the end of 2 mo, and 3) continued episodic exposure (11 cycles) resulted in an airway that was hyposensitive to AO exposure at 6 mo. These observations collectively associate with greater overall inflammation and epithelial cell death, particularly in early postnatal (2 mo), distal airways. PMID:25063800

  16. Retinoic Acid Regulates Embryonic Development of Mammalian Submandibular Salivary Glands

    PubMed Central

    Wright, Diana M.; Buenger, Deanna E.; Abashev, Timur M.; Lindeman, Robert P.; Ding, Jixiang; Sandell, Lisa L.

    2015-01-01

    Organogenesis is orchestrated by cell and tissue interactions mediated by molecular signals. Identification of relevant signals, and the tissues that generate and receive them, are important goals of developmental research. Here, we demonstrate that Retinoic Acid (RA) is a critical signaling molecule important for morphogenesis of mammalian submandibular salivary glands (SMG). By examining late stage RA deficient embryos of Rdh10 mutant mice we show that SMG development requires RA in a dose-dependent manner. Additionally, we find that active RA signaling occurs in SMG tissues, arising earlier than any other known marker of SMG development and persisting throughout gland morphogenesis. At the initial bud stage of development, we find RA production occurs in SMG mesenchyme, while RA signaling occurs in epithelium. We also demonstrate active RA signaling occurs in glands cultured ex vivo, and treatment with an inhibitor of RA signaling blocks growth and branching. Together these data identify RA signaling as a direct regulator of SMG organogenesis. PMID:26278034

  17. Structural insights into the regulation of aromatic amino acid hydroxylation.

    PubMed

    Fitzpatrick, Paul F

    2015-12-01

    The aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase are homotetramers, with each subunit containing a homologous catalytic domain and a divergent regulatory domain. The solution structure of the regulatory domain of tyrosine hydroxylase establishes that it contains a core ACT domain similar to that in phenylalanine hydroxylase. The isolated regulatory domain of tyrosine hydroxylase forms a stable dimer, while that of phenylalanine hydroxylase undergoes a monomer-dimer equilibrium, with phenylalanine stabilizing the dimer. These solution properties are consistent with the regulatory mechanisms of the two enzymes, in that phenylalanine hydroxylase is activated by phenylalanine binding to an allosteric site, while tyrosine hydroxylase is regulated by binding of catecholamines in the active site.

  18. Differential regulation of EGFR-MAPK signaling by deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) in colon cancer

    PubMed Central

    Centuori, Sara M.; Martinez, Jesse D.

    2014-01-01

    A high fat diet coincides with elevated levels of bile acids. This elevation of bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR) mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway. PMID:25027205

  19. Differential regulation of EGFR-MAPK signaling by deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) in colon cancer.

    PubMed

    Centuori, Sara M; Martinez, Jesse D

    2014-10-01

    A high-fat diet coincides with increased levels of bile acids. This increase in bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway.

  20. Identification of genes regulated by UV/salicylic acid.

    SciTech Connect

    Paunesku, T.; Chang-Liu, C.-M.; Shearin-Jones, P.; Watson, C.; Milton, J.; Oryhon, J.; Salbego, D.; Milosavljevic, A.; Woloschak, G. E.; CuraGen Corp.

    2000-02-01

    Purpose : Previous work from the authors' group and others has demonstrated that some of the effects of UV irradiation on gene expression are modulated in response to the addition of salicylic acid to irradiated cells. The presumed effector molecule responsible for this modulation is NF-kappaB. In the experiments described here, differential-display RT-PCR was used to identify those cDNAs that are differentially modulated by UV radiation with and without the addition of salicylic acid. Materials and methods : Differential-display RT-PCR was used to identify differentially expressed genes. Results : Eight such cDNAs are presented: lactate dehydrogenase (LDH-beta), nuclear encoded mitochondrial NADH ubiquinone reductase 24kDa (NDUFV2), elongation initiation factor 4B (eIF4B), nuclear dots protein SP100, nuclear encoded mitochondrial ATPase inhibitor (IF1), a cDNA similar to a subunit of yeast CCAAT transcription factor HAP5, and two expressed sequence tags (AA187906 and AA513156). Conclusions : Sequences of four of these genes contained NF-kappaB DNA binding sites of the type that may attract transrepressor p55/p55 NF-kappaB homodimers. Down-regulation of these genes upon UV irradiation may contribute to increased cell survival via suppression of p53 independent apoptosis.

  1. Salicylic acid 3-hydroxylase regulates Arabidopsis leaf longevity by mediating salicylic acid catabolism

    PubMed Central

    Zhang, Kewei; Halitschke, Rayko; Yin, Changxi; Liu, Chang-Jun; Gan, Su-Sheng

    2013-01-01

    The plant hormone salicylic acid (SA) plays critical roles in plant defense, stress responses, and senescence. Although SA biosynthesis is well understood, the pathways by which SA is catabolized remain elusive. Here we report the identification and characterization of an SA 3-hydroxylase (S3H) involved in SA catabolism during leaf senescence. S3H is associated with senescence and is inducible by SA and is thus a key part of a negative feedback regulation system of SA levels during senescence. The enzyme converts SA (with a Km of 58.29 µM) to both 2,3-dihydroxybenzoic acid (2,3-DHBA) and 2,5-DHBA in vitro but only 2,3-DHBA in vivo. The s3h knockout mutants fail to produce 2,3-DHBA sugar conjugates, accumulate very high levels of SA and its sugar conjugates, and exhibit a precocious senescence phenotype. Conversely, the gain-of-function lines contain high levels of 2,3-DHBA sugar conjugates and extremely low levels of SA and its sugar conjugates and display a significantly extended leaf longevity. This research reveals an elegant SA catabolic mechanism by which plants regulate SA levels by converting it to 2,3-DHBA to prevent SA overaccumulation. The research also provides strong molecular genetic evidence for an important role of SA in regulating the onset and rate of leaf senescence. PMID:23959884

  2. Salicylic acid 3-hydroxylase regulates Arabidopsis leaf longevity by mediating salicylic acid catabolism.

    PubMed

    Zhang, Kewei; Halitschke, Rayko; Yin, Changxi; Liu, Chang-Jun; Gan, Su-Sheng

    2013-09-03

    The plant hormone salicylic acid (SA) plays critical roles in plant defense, stress responses, and senescence. Although SA biosynthesis is well understood, the pathways by which SA is catabolized remain elusive. Here we report the identification and characterization of an SA 3-hydroxylase (S3H) involved in SA catabolism during leaf senescence. S3H is associated with senescence and is inducible by SA and is thus a key part of a negative feedback regulation system of SA levels during senescence. The enzyme converts SA (with a Km of 58.29 µM) to both 2,3-dihydroxybenzoic acid (2,3-DHBA) and 2,5-DHBA in vitro but only 2,3-DHBA in vivo. The s3h knockout mutants fail to produce 2,3-DHBA sugar conjugates, accumulate very high levels of SA and its sugar conjugates, and exhibit a precocious senescence phenotype. Conversely, the gain-of-function lines contain high levels of 2,3-DHBA sugar conjugates and extremely low levels of SA and its sugar conjugates and display a significantly extended leaf longevity. This research reveals an elegant SA catabolic mechanism by which plants regulate SA levels by converting it to 2,3-DHBA to prevent SA overaccumulation. The research also provides strong molecular genetic evidence for an important role of SA in regulating the onset and rate of leaf senescence.

  3. Comparative Genomics of Regulation of Fatty Acid and Branched-chain Amino Acid Utilization in Proteobacteria

    SciTech Connect

    Kazakov, Alexey E.; Rodionov, Dmitry A.; Arkin, Adam Paul; Dubchak, Inna; Gelfand, Mikhail S.; Alm, Eric

    2008-10-31

    Bacteria can use branched-chain amino acids (ILV, i.e. isoleucine, leucine, valine) and fatty acids (FA) as sole carbon and energy sources convering ILV into acetyl-CoA, propanoyl-CoA and propionyl-CoA, respectively. In this work, we used the comparative genomic approach to identify candidate transcriptional factors and DNA motifs that control ILV and FA utilization pathways in proteobacteria. The metabolic regulons were characterized based on the identification and comparison of candidate transcription factor binding sites in groups of phylogenetically related genomes. The reconstructed ILV/FA regulatory network demonstrates considerable variability and involves six transcriptional factors from the MerR, TetR and GntR families binding to eleven distinct DNA motifs. The ILV degradation genes in gamma- and beta-proteobacteria are mainly regulated by anovel regulator from the MerR family (e.g., LiuR in Pseudomonas aeruginosa) (40 species), in addition, the TetR-type regulator LiuQ was identified in some beta-proteobacteria (8 species). Besides the core set of ILV utilization genes, the LiuR regulon in some lineages is expanded to include genes from other metabolic pathways, such as the glyoxylate shunt and glutamate synthase in the Shewanella species. The FA degradation genes are controlled by four regulators including FadR in gamma-proteobacteria (34 species), PsrA in gamma- and beta-proteobacteria (45 species), FadP in beta-proteobacteria (14 species), and LiuR orthologs in alpha-proteobacteria (22 species). The remarkable variability of the regulatory systems associated with the FA degradation pathway is discussed from the functional and evolutionary points of view.

  4. Comparative genomics of regulation of fatty acid and branched-chain amino acid utilization in proteobacteria.

    PubMed

    Kazakov, Alexey E; Rodionov, Dmitry A; Alm, Eric; Arkin, Adam Paul; Dubchak, Inna; Gelfand, Mikhail S

    2009-01-01

    Bacteria can use branched-chain amino acids (ILV, i.e., isoleucine, leucine, valine) and fatty acids (FAs) as sole carbon and energy sources converting ILV into acetyl-coenzyme A (CoA), propanoyl-CoA, and propionyl-CoA, respectively. In this work, we used the comparative genomic approach to identify candidate transcriptional factors and DNA motifs that control ILV and FA utilization pathways in proteobacteria. The metabolic regulons were characterized based on the identification and comparison of candidate transcription factor binding sites in groups of phylogenetically related genomes. The reconstructed ILV/FA regulatory network demonstrates considerable variability and involves six transcriptional factors from the MerR, TetR, and GntR families binding to 11 distinct DNA motifs. The ILV degradation genes in gamma- and betaproteobacteria are regulated mainly by a novel regulator from the MerR family (e.g., LiuR in Pseudomonas aeruginosa) (40 species); in addition, the TetR-type regulator LiuQ was identified in some betaproteobacteria (eight species). Besides the core set of ILV utilization genes, the LiuR regulon in some lineages is expanded to include genes from other metabolic pathways, such as the glyoxylate shunt and glutamate synthase in Shewanella species. The FA degradation genes are controlled by four regulators including FadR in gammaproteobacteria (34 species), PsrA in gamma- and betaproteobacteria (45 species), FadP in betaproteobacteria (14 species), and LiuR orthologs in alphaproteobacteria (22 species). The remarkable variability of the regulatory systems associated with the FA degradation pathway is discussed from functional and evolutionary points of view.

  5. The role of abscisic acid in regulating cucumber fruit development and ripening and its transcriptional regulation.

    PubMed

    Wang, Yanping; Wang, Ya; Ji, Kai; Dai, Shengjie; Hu, Ying; Sun, Liang; Li, Qian; Chen, Pei; Sun, Yufei; Duan, Chaorui; Wu, Yan; Luo, Hao; Zhang, Dian; Guo, Yangdong; Leng, Ping

    2013-03-01

    Cucumber (Cucumis sativus L.), a kind of fruit usually harvested at the immature green stage, belongs to non-climacteric fruit. To investigate the contribution of abscisic acid (ABA) to cucumber fruit development and ripening, variation in ABA level was investigated and a peak in ABA level was found in pulp before fruit get fully ripe. To clarify this point further, exogenous ABA was applied to cucumber fruits at two different development stages. Results showed that ABA application at the turning stage promotes cucumber fruit ripening, while application at the immature green stage had inconspicuous effects. In addition, with the purpose of understanding the transcriptional regulation of ABA, two partial cDNAs of CsNCED1 and CsNCED2 encoding 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthetic pathway; one partial cDNA of CsCYP707A1 for 8'-hydroxylase, a key enzyme in the oxidative catabolism of ABA and two partial cDNAs of CsBG1 and CsBG2 for β-glucosidase (BG) that hydrolyzes ABA glucose ester (ABA-GE) to release active ABA were cloned from cucumber. The DNA and deduced amino acid sequences of these obtained genes respectively showed high similarities to their homologous genes in other plants. Real-time PCR analysis revealed that ABA content may be regulated by its biosynthesis (CsNCEDs), catabolism (CsCYP707A1) and reactivation genes (CsBGs) at the transcriptional level during cucumber fruit development and ripening, in response to ABA application, dehydration and pollination, among which CsNCED1, CsCYP707A1 and CsBG1 were highly expressed in pulp and may play more important roles in regulating ABA metabolism. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  6. Muricholic bile acids are potent regulators of bile acid synthesis via a positive feedback mechanism.

    PubMed

    Hu, X; Bonde, Y; Eggertsen, G; Rudling, M

    2014-01-01

    Bile acid (BA) synthesis is regulated by negative feedback end-product inhibition, initiated by farnesoid X receptors (FXRs) in liver and gut. Studies on cholic acid (CA)-free Cyp8b1(-/-) mice have concluded that CA is a potent suppressor of BA synthesis. Cyp8b1(-/-) mice have increased BA synthesis and an enlarged BA pool, a phenotype shared with bile-duct-ligated, antibiotics-administered and with germ-free mice. Studies on such mice have concluded BA synthesis is induced due to reduced hormonal signalling by fibroblast growth factor (FGF)15 from intestine to liver. A mutual finding in these models is that potent FXR-agonistic BAs are reduced. We hypothesized that the absence of the potent FXR agonist deoxycholic acid (DCA) may be important for the induction of BA synthesis in these situations. Two of these models were investigated, antibiotic treatment and Cyp8b1(-/-) mice and their combination. Secondary BA formation was inhibited by ampicillin (AMP) given to wild-type and Cyp8b1(-/-) mice. We then administered CA, chenodeoxycholic acid (CDCA) or DCA to AMP-treated Cyp8b1(-/-) mice. Our data show that the phenotype of AMP-treated wild-type mice resembles that of Cyp8b1(-/-) mice with fourfold induced Cyp7a1 expression, increased intestinal apical sodium-dependent BA transporter expression and increased hepatic BA levels. We also show that reductions in the FXR-agonistic BAs CDCA, CA, DCA or lithocholic acid cannot explain this phenotype; instead, it is likely due to increases in levels of α- and β-muricholic BAs and ursodeoxycholic acid, three FXR-antagonistic BAs. Our findings reveal a potent positive feedback mechanism for regulation of BA synthesis in mice that appears to be sufficient without endocrine effects of FGF15 on Cyp7a1. This mechanism will be fundamental in understanding BA metabolism in both mice and humans. © 2013 The Association for the Publication of the Journal of Internal Medicine.

  7. Calcineurin mediates homeostatic synaptic plasticity by regulating retinoic acid synthesis

    PubMed Central

    Arendt, Kristin L.; Zhang, Zhenjie; Ganesan, Subhashree; Hintze, Maik; Shin, Maggie M.; Tang, Yitai; Cho, Ahryon; Graef, Isabella A.; Chen, Lu

    2015-01-01

    Homeostatic synaptic plasticity is a form of non-Hebbian plasticity that maintains stability of the network and fidelity for information processing in response to prolonged perturbation of network and synaptic activity. Prolonged blockade of synaptic activity decreases resting Ca2+ levels in neurons, thereby inducing retinoic acid (RA) synthesis and RA-dependent homeostatic synaptic plasticity; however, the signal transduction pathway that links reduced Ca2+-levels to RA synthesis remains unknown. Here we identify the Ca2+-dependent protein phosphatase calcineurin (CaN) as a key regulator for RA synthesis and homeostatic synaptic plasticity. Prolonged inhibition of CaN activity promotes RA synthesis in neurons, and leads to increased excitatory and decreased inhibitory synaptic transmission. These effects of CaN inhibitors on synaptic transmission are blocked by pharmacological inhibitors of RA synthesis or acute genetic deletion of the RA receptor RARα. Thus, CaN, acting upstream of RA, plays a critical role in gating RA signaling pathway in response to synaptic activity. Moreover, activity blockade-induced homeostatic synaptic plasticity is absent in CaN knockout neurons, demonstrating the essential role of CaN in RA-dependent homeostatic synaptic plasticity. Interestingly, in GluA1 S831A and S845A knockin mice, CaN inhibitor- and RA-induced regulation of synaptic transmission is intact, suggesting that phosphorylation of GluA1 C-terminal serine residues S831 and S845 is not required for CaN inhibitor- or RA-induced homeostatic synaptic plasticity. Thus, our study uncovers an unforeseen role of CaN in postsynaptic signaling, and defines CaN as the Ca2+-sensing signaling molecule that mediates RA-dependent homeostatic synaptic plasticity. PMID:26443861

  8. Retinoic Acid Regulates the Expression of Photoreceptor Transcription Factor NRL*

    PubMed Central

    Khanna, Hemant; Akimoto, Masayuki; Siffroi-Fernandez, Sandrine; Friedman, James S.; Hicks, David; Swaroop, Anand

    2006-01-01

    NRL (neural retina leucine zipper) is a key basic motif-leucine zipper (bZIP) transcription factor, which orchestrates rod photoreceptor differentiation by activating the expression of rod-specific genes. The deletion of Nrl in mice results in functional cones that are derived from rod precursors. However, signaling pathways modulating the expression or activity of NRL have not been elucidated. Here, we show that retinoic acid (RA), a diffusible factor implicated in rod development, activates the expression of NRL in serum-deprived Y79 human retinoblastoma cells and in primary cultures of rat and porcine photoreceptors. The effect of RA is mimicked by TTNPB, a RA receptor agonist, and requires new protein synthesis. DNaseI footprinting and electrophoretic mobility shift assays (EMSA) using bovine retinal nuclear extract demonstrate that RA response elements (RAREs) identified within the Nrl promoter bind to RA receptors. Furthermore, in transiently transfected Y79 and HEK293 cells the activity of Nrl-promoter driving a luciferase reporter gene is induced by RA, and this activation is mediated by RAREs. Our data suggest that signaling by RA via RA receptors regulates the expression of NRL, providing a framework for delineating early steps in photoreceptor cell fate determination. PMID:16854989

  9. Pharmacological activation of lysophosphatidic acid receptors regulates erythropoiesis.

    PubMed

    Lin, Kuan-Hung; Ho, Ya-Hsuan; Chiang, Jui-Chung; Li, Meng-Wei; Lin, Shi-Hung; Chen, Wei-Min; Chiang, Chi-Ling; Lin, Yu-Nung; Yang, Ya-Jan; Chen, Chiung-Nien; Lu, Jenher; Huang, Chang-Jen; Tigyi, Gabor; Yao, Chao-Ling; Lee, Hsinyu

    2016-05-31

    Lysophosphatidic acid (LPA), a growth factor-like phospholipid, regulates numerous physiological functions, including cell proliferation and differentiation. In a previous study, we have demonstrated that LPA activates erythropoiesis by activating the LPA 3 receptor subtype (LPA3) under erythropoietin (EPO) induction. In the present study, we applied a pharmacological approach to further elucidate the functions of LPA receptors during red blood cell (RBC) differentiation. In K562 human erythroleukemia cells, knockdown of LPA2 enhanced erythropoiesis, whereas knockdown of LPA3 inhibited RBC differentiation. In CD34(+) human hematopoietic stem cells (hHSC) and K526 cells, the LPA3 agonist 1-oleoyl-2-methyl-sn-glycero-3-phosphothionate (2S-OMPT) promoted erythropoiesis, whereas the LPA2 agonist dodecyl monophosphate (DMP) and the nonlipid specific agonist GRI977143 (GRI) suppressed this process. In zebrafish embryos, hemoglobin expression was significantly increased by 2S-OMPT treatment but was inhibited by GRI. Furthermore, GRI treatment decreased, whereas 2S-OMPT treatment increased RBC counts and amount of hemoglobin level in adult BALB/c mice. These results indicate that LPA2 and LPA3 play opposing roles during RBC differentiation. The pharmacological activation of LPA receptor subtypes represent a novel strategies for augmenting or inhibiting erythropoiesis.

  10. Metabolic regulation of the plant hormone indole-3-acetic acid

    SciTech Connect

    Jerry D. Cohen

    2009-11-01

    The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and that over-express each member in the family in terms of the level and route of IAA biosynthesis. Together, these allowed further development of a comprehensive picture of the pathways and regulatory components that are involved in IAA homeostasis in higher plants.

  11. Pharmacological activation of lysophosphatidic acid receptors regulates erythropoiesis

    PubMed Central

    Lin, Kuan-Hung; Ho, Ya-Hsuan; Chiang, Jui-Chung; Li, Meng-Wei; Lin, Shi-Hung; Chen, Wei-Min; Chiang, Chi-Ling; Lin, Yu-Nung; Yang, Ya-Jan; Chen, Chiung-Nien; Lu, Jenher; Huang, Chang-Jen; Tigyi, Gabor; Yao, Chao-Ling; Lee, Hsinyu

    2016-01-01

    Lysophosphatidic acid (LPA), a growth factor-like phospholipid, regulates numerous physiological functions, including cell proliferation and differentiation. In a previous study, we have demonstrated that LPA activates erythropoiesis by activating the LPA 3 receptor subtype (LPA3) under erythropoietin (EPO) induction. In the present study, we applied a pharmacological approach to further elucidate the functions of LPA receptors during red blood cell (RBC) differentiation. In K562 human erythroleukemia cells, knockdown of LPA2 enhanced erythropoiesis, whereas knockdown of LPA3 inhibited RBC differentiation. In CD34+ human hematopoietic stem cells (hHSC) and K526 cells, the LPA3 agonist 1-oleoyl-2-methyl-sn-glycero-3-phosphothionate (2S-OMPT) promoted erythropoiesis, whereas the LPA2 agonist dodecyl monophosphate (DMP) and the nonlipid specific agonist GRI977143 (GRI) suppressed this process. In zebrafish embryos, hemoglobin expression was significantly increased by 2S-OMPT treatment but was inhibited by GRI. Furthermore, GRI treatment decreased, whereas 2S-OMPT treatment increased RBC counts and amount of hemoglobin level in adult BALB/c mice. These results indicate that LPA2 and LPA3 play opposing roles during RBC differentiation. The pharmacological activation of LPA receptor subtypes represent a novel strategies for augmenting or inhibiting erythropoiesis. PMID:27244685

  12. Retinoic acid regulates the expression of photoreceptor transcription factor NRL.

    PubMed

    Khanna, Hemant; Akimoto, Masayuki; Siffroi-Fernandez, Sandrine; Friedman, James S; Hicks, David; Swaroop, Anand

    2006-09-15

    NRL (neural retina leucine zipper) is a key basic motif-leucine zipper (bZIP) transcription factor, which orchestrates rod photoreceptor differentiation by activating the expression of rod-specific genes. The deletion of Nrl in mice results in functional cones that are derived from rod precursors. However, signaling pathways modulating the expression or activity of NRL have not been elucidated. Here, we show that retinoic acid (RA), a diffusible factor implicated in rod development, activates the expression of NRL in serum-deprived Y79 human retinoblastoma cells and in primary cultures of rat and porcine photoreceptors. The effect of RA is mimicked by TTNPB, a RA receptor agonist, and requires new protein synthesis. DNaseI footprinting and electrophoretic mobility shift assays (EMSA) using bovine retinal nuclear extract demonstrate that RA response elements (RAREs) identified within the Nrl promoter bind to RA receptors. Furthermore, in transiently transfected Y79 and HEK293 cells the activity of Nrl-promoter driving a luciferase reporter gene is induced by RA, and this activation is mediated by RAREs. Our data suggest that signaling by RA via RA receptors regulates the expression of NRL, providing a framework for delineating early steps in photoreceptor cell fate determination.

  13. Retinoic acid regulates embryonic development of mammalian submandibular salivary glands.

    PubMed

    Wright, Diana M; Buenger, Deanna E; Abashev, Timur M; Lindeman, Robert P; Ding, Jixiang; Sandell, Lisa L

    2015-11-01

    Organogenesis is orchestrated by cell and tissue interactions mediated by molecular signals. Identification of relevant signals, and the tissues that generate and receive them, are important goals of developmental research. Here, we demonstrate that Retinoic Acid (RA) is a critical signaling molecule important for morphogenesis of mammalian submandibular salivary glands (SMG). By examining late stage RA deficient embryos of Rdh10 mutant mice we show that SMG development requires RA in a dose-dependent manner. Additionally, we find that active RA signaling occurs in SMG tissues, arising earlier than any other known marker of SMG development and persisting throughout gland morphogenesis. At the initial bud stage of development, we find RA production occurs in SMG mesenchyme, while RA signaling occurs in epithelium. We also demonstrate active RA signaling occurs in glands cultured ex vivo, and treatment with an inhibitor of RA signaling blocks growth and branching. Together these data identify RA signaling as a direct regulator of SMG organogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Regulation of lipid metabolism by obeticholic acid in hyperlipidemic hamsters.

    PubMed

    Dong, Bin; Young, Mark; Liu, Xueqing; Singh, Amar Bahadur; Liu, Jingwen

    2017-02-01

    The farnesoid X receptor (FXR) plays critical roles in plasma cholesterol metabolism, in particular HDL-cholesterol (HDL-C) homeostasis. Obeticholic acid (OCA) is a FXR agonist being developed for treating various chronic liver diseases. Previous studies reported inconsistent effects of OCA on regulating plasma cholesterol levels in different animal models and in different patient populations. The mechanisms underlying its divergent effects have not yet been thoroughly investigated. The scavenger receptor class B type I (SR-BI) is a FXR-modulated gene and the major receptor for HDL-C. We investigated the effects of OCA on hepatic SR-BI expression and correlated such effects with plasma HDL-C levels and hepatic cholesterol efflux in hyperlipidemic hamsters. We demonstrated that OCA induced a time-dependent reduction in serum HDL-C levels after 14 days of treatment, which was accompanied by a significant reduction of liver cholesterol content and increases in fecal cholesterol in OCA-treated hamsters. Importantly, hepatic SR-BI mRNA and protein levels in hamsters were increased to 1.9- and 1.8-fold of control by OCA treatment. Further investigations in normolipidemic hamsters did not reveal OCA-induced changes in serum HDL-C levels or hepatic SR-BI expression. We conclude that OCA reduces plasma HDL-C levels and promotes transhepatic cholesterol efflux in hyperlipidemic hamsters via a mechanism involving upregulation of hepatic SR-BI.

  15. Hypochlorous acid regulates neutrophil extracellular trap release in humans.

    PubMed

    Palmer, L J; Cooper, P R; Ling, M R; Wright, H J; Huissoon, A; Chapple, I L C

    2012-02-01

    Neutrophil extracellular traps (NETs) comprise extracellular chromatin and granule protein complexes that immobilize and kill bacteria. NET release represents a recently discovered, novel anti-microbial strategy regulated non-exclusively by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase generation of reactive oxygen intermediates (ROIs), particularly hydrogen peroxide. This study aimed to characterize the role of ROIs in the process of NET release and to identify the dominant ROI trigger. We employed various enzymes, inhibitors and ROIs to record their effect fluorometrically on in vitro NET release by human peripheral blood neutrophils. Treatment with exogenous superoxide dismutase (SOD) supported the established link between hydrogen peroxide and NET production. However, treatment with myeloperoxidase inhibitors and direct addition of hypochlorous acid (HOCl; generated in situ from sodium hypochlorite) established that HOCl was a necessary and sufficient ROI for NET release. This was confirmed by the ability of HOCl to stimulate NET release in chronic granulomatous disease (CGD) patient neutrophils which, due to the lack of a functional NADPH oxidase, also lack the capacity for NET release in response to classical stimuli. Moreover, the exogenous addition of taurine, abundantly present within the neutrophil cytosol, abrogated NET production stimulated by phorbol myristate acetate (PMA) and HOCl, providing a novel mode of cytoprotection by taurine against oxidative stress by taurine.

  16. Novel Roles for Notch3 and Notch4 Receptors in Gene Expression and Susceptibility to Ozone-Induced Lung Inflammation in Mice

    PubMed Central

    McCaw, Zachary; Gladwell, Wesley; Trivedi, Shweta; Bushel, Pierre R.; Kleeberger, Steven R.

    2015-01-01

    Background Ozone is a highly toxic air pollutant and global health concern. Mechanisms of genetic susceptibility to ozone-induced lung inflammation are not completely understood. We hypothesized that Notch3 and Notch4 are important determinants of susceptibility to ozone-induced lung inflammation. Methods Wild-type (WT), Notch3 (Notch3–/–), and Notch4 (Notch4–/–) knockout mice were exposed to ozone (0.3 ppm) or filtered air for 6–72 hr. Results Relative to air-exposed controls, ozone increased bronchoalveolar lavage fluid (BALF) protein, a marker of lung permeability, in all genotypes, but significantly greater concentrations were found in Notch4–/– compared with WT and Notch3–/– mice. Significantly greater mean numbers of BALF neutrophils were found in Notch3–/– and Notch4–/– mice compared with WT mice after ozone exposure. Expression of whole lung Tnf was significantly increased after ozone in Notch3–/– and Notch4–/– mice, and was significantly greater in Notch3–/– compared with WT mice. Statistical analyses of the transcriptome identified differentially expressed gene networks between WT and knockout mice basally and after ozone, and included Trim30, a member of the inflammasome pathway, and Traf6, an inflammatory signaling member. Conclusions These novel findings are consistent with Notch3 and Notch4 as susceptibility genes for ozone-induced lung injury, and suggest that Notch receptors protect against innate immune inflammation. Citation Verhein KC, McCaw Z, Gladwell W, Trivedi S, Bushel PR, Kleeberger SR. 2015. Novel roles for Notch3 and Notch4 receptors in gene expression and susceptibility to ozone-induced lung inflammation in mice. Environ Health Perspect 123:799–805; http://dx.doi.org/10.1289/ehp.1408852 PMID:25658374

  17. Ozone-induced changes in photosynthesis and photorespiration of hybrid poplar in relation to the developmental stage of the leaves.

    PubMed

    Bagard, Matthieu; Le Thiec, Didier; Delacote, Emilien; Hasenfratz-Sauder, Marie-Paule; Banvoy, Jacques; Gérard, Joëlle; Dizengremel, Pierre; Jolivet, Yves

    2008-12-01

    Young poplar trees (Populus tremula Michx. x Populus alba L. clone INRA 717-1B4) were subjected to 120 ppb of ozone for 35 days in phytotronic chambers. Treated trees displayed precocious leaf senescence and visible symptoms of injury (dark brown/black upper surface stippling) exclusively observed on fully expanded leaves. In these leaves, ozone reduced parameters related to photochemistry (Chl content and maximum rate of photosynthetic electron transport) and photosynthetic CO(2) fixation [net CO(2) assimilation, Rubisco (ribulose-1,5-bisphosphate carboxylase oxygenase) activity and maximum velocity of Rubisco for carboxylation]. In fully expanded leaves, the rate of photorespiration as estimated from Chl fluorescence was markedly impaired by the ozone treatment together with the activity of photorespiratory enzymes (Rubisco and glycolate oxidase). Immunoblot analysis revealed a decrease in the content of serine hydroxymethyltransferase in treated mature leaves, while the content of the H subunit of the glycine decarboxylase complex was not modified. Leaves in the early period of expansion were exempt from visible symptoms of injury and remained unaffected as regards all measured parameters. Leaves reaching full expansion under ozone exposure showed potential responses of protection (stimulation of mitochondrial respiration and transitory stomatal closure). Our data underline the major role of leaf phenology in ozone sensitivity of photosynthetic processes and reveal a marked ozone-induced inhibition of photorespiration.

  18. Cortisol Regulates Acid Secretion of H+-ATPase-rich Ionocytes in Zebrafish (Danio rerio) Embryos

    PubMed Central

    Lin, Chia-Hao; Shih, Tin-Han; Liu, Sian-Tai; Hsu, Hao-Hsuan; Hwang, Pung-Pung

    2015-01-01

    Systemic acid-base regulation is vital for physiological processes in vertebrates. Freshwater (FW) fish live in an inconstant environment, and thus frequently face ambient acid stress. FW fish have to efficiently modulate their acid secretion processes for body fluid acid-base homeostasis during ambient acid challenge; hormonal control plays an important role in such physiological regulation. The hormone cortisol was previously proposed to be associated with acid base regulation in FW fish; however, the underlying mechanism has not been fully described. In the present study, mRNA expression of acid-secreting related transporters and cyp11b (encoding an enzyme involved in cortisol synthesis) in zebrafish embryos was stimulated by treatment with acidic FW (AFW, pH 4.0) for 3 d. Exogenous cortisol treatment (20 mg/L, 3 d) resulted in upregulated expression of transporters related to acid secretion and increased acid secretion function at the organism level in zebrafish embryos. Moreover, cortisol treatment also significantly increased the acid secretion capacity of H+-ATPase-rich cells (HRCs) at the cellular level. In loss-of-function experiments, microinjection of glucocorticoid receptor (GR) morpholino (MO) suppressed the expression of acid-secreting related transporters, and decreased acid secretion function at both the organism and cellular levels; on the other hand, mineralocorticoid receptor (MR) MO did not induce any effects. Such evidence supports the hypothesized role of cortisol in fish acid-base regulation, and provides new insights into the roles of cortisol; cortisol-GR signaling stimulates zebrafish acid secretion function through transcriptional/translational regulation of the transporters and upregulation of acid secretion capacity in each acid-secreting ionocyte. PMID:26635615

  19. SRC-mediated EGF Receptor Activation Regulates Ozone-induced Interleukin 8 Expression in Human Bronchial Epithelial Cells

    EPA Science Inventory

    BACKGROUND: Human exposure to ozone (03) results in pulmonary function decrements and airway inflammation. The mechanisms underlying these adverse effects remain unclear. Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of lung inflammation. ...

  20. SRC-mediated EGF Receptor Activation Regulates Ozone-induced Interleukin 8 Expression in Human Bronchial Epithelial Cells

    EPA Science Inventory

    BACKGROUND: Human exposure to ozone (03) results in pulmonary function decrements and airway inflammation. The mechanisms underlying these adverse effects remain unclear. Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of lung inflammation. ...

  1. Ozone-induced kiwifruit ripening delay is mediated by ethylene biosynthesis inhibition and cell wall dismantling regulation.

    PubMed

    Minas, Ioannis S; Vicente, Ariel R; Dhanapal, Arun Prabhu; Manganaris, George A; Goulas, Vlasios; Vasilakakis, Miltiadis; Crisosto, Carlos H; Molassiotis, Athanassios

    2014-12-01

    Ozone treatments are used to preserve quality during cold storage of commercially important fruits due to its ethylene oxidizing capacity and its antimicrobial attributes. To address whether or not ozone also modulates ripening by directly affecting fruit physiology, kiwifruit (Actinidia deliciosa cv. 'Hayward') were stored in very low ethylene atmosphere at 0°C (95% RH) in air (control) or in the presence of ozone (0.3μLL(-1)) for 2 or 4 months and subsequently ripened at 20°C (90% RH) for up to 8d. Ozone-treated kiwifruit showed a significant delay of ripening during maintenance at 20°C, accompanied by a marked decrease in ethylene biosynthesis due to inhibited AdACS1 and AdACO1 expression and reduced ACC synthase (ACS) and ACC oxidase (ACO) enzyme activity. Furthermore, ozone-treated fruit exhibited a marked reduction in flesh softening and cell wall disassembly. This effect was associated with reduced cell wall swelling and pectin and neutral sugar solubilization and was correlated with the inhibition of cell wall degrading enzymes activity, such as polygalacturonase (PG) and endo-1,4-β-glucanase/1,4-β-glucosidase (EGase/glu). Conclusively, the present study indicated that ozone may exert major residual effects in fruit ripening physiology and suggested that ethylene biosynthesis and cell walls turnover are specifically targeted by ozone.

  2. Metabolic pathways regulated by abscisic acid, salicylic acid and γ-aminobutyric acid in association with improved drought tolerance in creeping bentgrass (Agrostis stolonifera).

    PubMed

    Li, Zhou; Yu, Jingjin; Peng, Yan; Huang, Bingru

    2017-01-01

    Abscisic acid (ABA), salicylic acid (SA) and γ-aminobutyric acid (GABA) are known to play roles in regulating plant stress responses. This study was conducted to determine metabolites and associated pathways regulated by ABA, SA and GABA that could contribute to drought tolerance in creeping bentgrass (Agrostis stolonifera). Plants were foliar sprayed with ABA (5 μM), GABA (0.5 mM) and SA (10 μM) or water (untreated control) prior to 25 days drought stress in controlled growth chambers. Application of ABA, GABA or SA had similar positive effects on alleviating drought damages, as manifested by the maintenance of lower electrolyte leakage and greater relative water content in leaves of treated plants relative to the untreated control. Metabolic profiling showed that ABA, GABA and SA induced differential metabolic changes under drought stress. ABA mainly promoted the accumulation of organic acids associated with tricarboxylic acid cycle (aconitic acid, succinic acid, lactic acid and malic acid). SA strongly stimulated the accumulation of amino acids (proline, serine, threonine and alanine) and carbohydrates (glucose, mannose, fructose and cellobiose). GABA enhanced the accumulation of amino acids (GABA, glycine, valine, proline, 5-oxoproline, serine, threonine, aspartic acid and glutamic acid) and organic acids (malic acid, lactic acid, gluconic acid, malonic acid and ribonic acid). The enhanced drought tolerance could be mainly due to the enhanced respiration metabolism by ABA, amino acids and carbohydrates involved in osmotic adjustment (OA) and energy metabolism by SA, and amino acid metabolism related to OA and stress-defense secondary metabolism by GABA. © 2016 Scandinavian Plant Physiology Society.

  3. Regulation of Connexin-Based Channels by Fatty Acids

    PubMed Central

    Puebla, Carlos; Retamal, Mauricio A.; Acuña, Rodrigo; Sáez, Juan C.

    2017-01-01

    In this mini-review, we briefly summarize the current knowledge about the effects of fatty acids (FAs) on connexin-based channels, as well as discuss the limited information about the impact FAs may have on pannexins (Panxs). FAs regulate diverse cellular functions, some of which are explained by changes in the activity of channels constituted by connexins (Cxs) or Panxs, which are known to play critical roles in maintaining the functional integrity of diverse organs and tissues. Cxs are transmembrane proteins that oligomerize into hexamers to form hemichannels (HCs), which in turn can assemble into dodecamers to form gap junction channels (GJCs). While GJCs communicate the cytoplasm of contacting cells, HCs serve as pathways for the exchange of ions and small molecules between the intra and extracellular milieu. Panxs, as well as Cx HCs, form channels at the plasma membrane that enable the interchange of molecules between the intra and extracellular spaces. Both Cx- and Panx-based channels are controlled by several post-translational modifications. However, the mechanism of action of FAs on these channels has not been described in detail. It has been shown however that FAs frequently decrease GJC-mediated cell-cell communication. The opposite effect also has been described for HC or Panx-dependent intercellular communication, where, the acute FA effect can be reversed upon washout. Additionally, changes in GJCs mediated by FAs have been associated with post-translational modifications (e.g., phosphorylation), and seem to be directly related to chemical properties of FAs (e.g., length of carbon chain and/or degree of saturation), but this possible link remains poorly understood. PMID:28174541

  4. Regulation of Connexin-Based Channels by Fatty Acids.

    PubMed

    Puebla, Carlos; Retamal, Mauricio A; Acuña, Rodrigo; Sáez, Juan C

    2017-01-01

    In this mini-review, we briefly summarize the current knowledge about the effects of fatty acids (FAs) on connexin-based channels, as well as discuss the limited information about the impact FAs may have on pannexins (Panxs). FAs regulate diverse cellular functions, some of which are explained by changes in the activity of channels constituted by connexins (Cxs) or Panxs, which are known to play critical roles in maintaining the functional integrity of diverse organs and tissues. Cxs are transmembrane proteins that oligomerize into hexamers to form hemichannels (HCs), which in turn can assemble into dodecamers to form gap junction channels (GJCs). While GJCs communicate the cytoplasm of contacting cells, HCs serve as pathways for the exchange of ions and small molecules between the intra and extracellular milieu. Panxs, as well as Cx HCs, form channels at the plasma membrane that enable the interchange of molecules between the intra and extracellular spaces. Both Cx- and Panx-based channels are controlled by several post-translational modifications. However, the mechanism of action of FAs on these channels has not been described in detail. It has been shown however that FAs frequently decrease GJC-mediated cell-cell communication. The opposite effect also has been described for HC or Panx-dependent intercellular communication, where, the acute FA effect can be reversed upon washout. Additionally, changes in GJCs mediated by FAs have been associated with post-translational modifications (e.g., phosphorylation), and seem to be directly related to chemical properties of FAs (e.g., length of carbon chain and/or degree of saturation), but this possible link remains poorly understood.

  5. Enzymatic oxalic acid regulation correlated with wood degradation in four brown-rot fungi

    Treesearch

    Anne Christine Steenkjær Hastrup; Frederick Green III; Patricia K. Lebow; Bo Jensen

    2012-01-01

    Oxalic acid is a key component in the initiation of brown-rot decay and it has been suggested that it plays multiple roles during the degradation process. Oxalic acid is accumulated to varying degrees among brown-rot fungi; however, details on active regulation are scarce. The accumulation of oxalic acid was measured in this study from wood degraded by the four brown-...

  6. [Regulating acid stress resistance of lactic acid bacteria--a review].

    PubMed

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-07-04

    As cell factories, lactic acid bacteria are widely used in food, agriculture, pharmaceutical and other industries. Acid stress is one the important survival challenges encountered by lactic acid bacteria both in fermentation process and in the gastrointestinal tract. Recently, the development of systems biology and metabolic engineering brings unprecedented opportunity for further elucidating the acid tolerance mechanisms and improving the acid stress resistance of lactic acid bacteria. This review addresses physiological mechanisms of lactic acid bacteria during acid stress. Moreover, strategies to improve the acid stress resistance of lactic acid were proposed.

  7. Characterization of Arabidopsis Acid Phosphatase Promoter and Regulation of Acid Phosphatase Expression

    PubMed Central

    Haran, Shoshan; Logendra, Sithes; Seskar, Mirjana; Bratanova, Margarita; Raskin, Ilya

    2000-01-01

    The expression and secretion of acid phosphatase (APase) was investigated in Indian mustard (Brassica juncea L. Czern.) plants using sensitive in vitro and activity gel assays. Phosphorus (P) starvation induced two APases in Indian mustard roots, only one of which was secreted. Northern-blot analysis indicated transcriptional regulation of APase expression. Polymerase chain reaction and Southern-blot analyses revealed two APase homologs in Indian mustard, whereas in Arabidopsis, only one APase homolog was detected. The Arabidopsis APase promoter region was cloned and fused to the β-glucuronidase (GUS) and green fluorescent protein (GFP) reporter genes. GUS expression was first evident in leaves of the P-starved Arabidopsis plants. In P-starved roots, the expression of GUS initiated in lateral root meristems followed by generalized expression throughout the root. GUS expression diminished with the addition of P to the medium. Expression of GFP in P-starved roots also initiated in the lateral root meristems and the recombinant GFP with the APase signal peptide was secreted by the roots into the medium. The APase promoter was specifically activated by low P levels. The removal of other essential elements or the addition of salicylic or jasmonic acids, known inducers of gene expression, did not activate the APase promoter. This novel APase promoter may be used as a plant-inducible gene expression system for the production of recombinant proteins and as a tool to study P metabolism in plants. PMID:11027712

  8. Ozone-induced changes in host-plant suitability: interactions of Keiferia lycopersicella and Lycopersicon esculentum

    SciTech Connect

    Trumble, J.T.; Hare, J.D.; Musselman, R.C.; McCool, P.M.

    1987-01-01

    Tomato pinworms, Keiferia lycopersicella (Walsingham), survived better and developed faster on tomato plants, Lycopersicon esculentum Mill., damaged by ozone than on plants not subjected to ozone fumigation. Other measures of fitness, including survival during pupation, sex ratio of adults, female longevity, and fecundity, were not affected. Analyses of ozonated foliage at zero, two and seven days following fumigation demonstrated a transient but significant increase (18-24%) in soluble protein concentration. Although the concentration of the total free amino acids in ozonated foliage did not increase significantly, significant changes were observed in at least 10 specific amino acids, some of which are critical for either insect development or the production of plant defensive chemicals. A reduction in total nitrogen in ozonated foliage at seven days postfumigation indicated that nitrogen was being translocated to other portions of the plant. The implications of increases in assimilable forms of nitrogen in ozonated foliage, which lead to improved host-plant suitability for insect herbivores, are discussed both in relation to some current ecological theories and in regard to pest-management strategies. 59 references, 1 figure, 4 tables.

  9. Cytosolic nucleic acid sensors and innate immune regulation.

    PubMed

    Ori, Daisuke; Murase, Motoya; Kawai, Taro

    2017-03-04

    During viral and bacterial infections, pathogen-derived cytosolic nucleic acids are recognized by the intracellular RNA sensors retinoic acid-inducible gene I and melanoma-differentiated gene 5 and intracellular DNA sensors, including cyclic-di-GMP-AMP synthase, absent in melanoma 2, interferon (IFN)-gamma inducible protein 16, polymerase III, and so on. Binding of intracellular nucleic acids to these sensors activates downstream signaling cascades, resulting in the production of type I IFNs and pro-inflammatory cytokines to induce appropriate systematic immune responses. While these sensors also recognize endogenous nucleic acids and activate immune responses, they can discriminate between self- and non-self-nucleic acids. However, dysfunction of these sensors or failure of regulatory mechanisms causes aberrant activation of immune response and autoimmune disorders. In this review, we focus on how intracellular immune sensors recognize exogenous nucleic acids and activate the innate immune system, and furthermore, how autoimmune diseases result from dysfunction of these sensors.

  10. Regulation of collagen biosynthesis by ascorbic acid: a review.

    PubMed Central

    Pinnell, S. R.

    1985-01-01

    L-ascorbic acid is an essential cofactor for lysyl hydroxylase and prolyl hydroxylase, enzymes essential for collagen biosynthesis. In addition, L-ascorbic acid preferentially stimulates collagen synthesis in a manner which appears unrelated to the effect of L-ascorbic acid on hydroxylation reactions. This reaction is stereospecific and unrelated to intracellular degradation of collagen. The effect apparently occurs at a transcriptional or translational level, since L-ascorbic acid preferentially stimulates collagen-specific mRNA. In addition, it stimulates lysyl hydroxylase activity but inhibits prolyl hydroxylase activity in human skin fibroblasts in culture. PMID:3008449

  11. Regulation of the Docosapentaenoic Acid/Docosahexaenoic Acid Ratio (DPA/DHA Ratio) in Schizochytrium limacinum B4D1.

    PubMed

    Zhang, Ke; Li, Huidong; Chen, Wuxi; Zhao, Minli; Cui, Haiyang; Min, Qingsong; Wang, Haijun; Chen, Shulin; Li, Demao

    2016-11-10

    Docosapentaenoic acid/docosahexaenoic acid ratio (DPA/DHA ratio) in Schizochytrium was relatively stable. But ideally the ratio of DPA/DHA will vary according to the desired end use. This study reports several ways of modulating the DPA/DHA ratio. Incubation times changed the DPA/DHA ratio, and changes in this ratio were associated with the variations in the saturated fatty acid (SFAs) content. Propionic acid sharply increased the SFAs content in lipids, dramatically decreased the even-chain SFAs content, and reduced the DPA/DHA ratio. Pentanoic acid (C5:0) and heptanoic acid (C7:0) had similar effects as propionic acid, whereas butyric acid (C4:0), hexanoic acid (C6:0), and octanoic acid (C8:0) did not change the fatty acid profile and the DPA/DHA ratio. Transcription analyses show that β-oxidation might be responsible for this phenomenon. Iodoacetamide upregulated polyunsaturated fatty acid (PUFA) synthase genes, reduced the DHA content, and improved the DPA content, causing the DPA/DHA ratio to increase. These results present new insights into the regulation of the DPA/DHA ratio.

  12. Retinoic acid regulation by CYP26 in vertebrate lens regeneration.

    PubMed

    Thomas, Alvin G; Henry, Jonathan J

    2014-02-15

    Xenopus laevis is among the few species that are capable of fully regenerating a lost lens de novo. This occurs upon removal of the lens, when secreted factors from the retina are permitted to reach the cornea epithelium and trigger it to form a new lens. Although many studies have investigated the retinal factors that initiate lens regeneration, relatively little is known about what factors support this process and make the cornea competent to form a lens. We presently investigate the role of Retinoic acid (RA) signaling in lens regeneration in Xenopus. RA is a highly important morphogen during vertebrate development, including the development of various eye tissues, and has been previously implicated in several regenerative processes as well. For instance, Wolffian lens regeneration in the newt requires active RA signaling. In contrast, we provide evidence here that lens regeneration in Xenopus actually depends on the attenuation of RA signaling, which is regulated by the RA-degrading enzyme CYP26. Using RT-PCR we examined the expression of RA synthesis and metabolism related genes within ocular tissues. We found expression of aldh1a1, aldh1a2, and aldh1a3, as well as cyp26a1 and cyp26b1 in both normal and regenerating corneal tissue. On the other hand, cyp26c1 does not appear to be expressed in either control or regenerating corneas, but it is expressed in the lens. Additionally in the lens, we found expression of aldh1a1 and aldh1a2, but not aldh1a3. Using an inhibitor of CYP26, and separately using exogenous retinoids, as well as RA signaling inhibitors, we demonstrate that CYP26 activity is necessary for lens regeneration to occur. We also find using phosphorylated Histone H3 labeling that CYP26 antagonism reduces cell proliferation in the cornea, and using qPCR we find that exogenous retinoids alter the expression of putative corneal stem cell markers. Furthermore, the Xenopus cornea is composed of an outer layer and inner basal epithelium, as well as a

  13. Xenobiotic, Bile Acid, and Cholesterol Transporters: Function and Regulation

    PubMed Central

    Aleksunes, Lauren M.

    2010-01-01

    Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting β polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) α and β] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory

  14. Ozone-induced respiratory illness during the repair of a portland cement kiln.

    PubMed

    Sanderson, W T; Almaguer, D; Kirk, L H

    1999-06-01

    Workers at a portland cement plant had experienced acute respiratory and eye irritation when performing maintenance inside a kiln. These episodes were associated with a bleach-like odor, which was only reported during maintenance operations. An industrial hygiene investigation was conducted to determine the cause of the illness. While workers replaced refractory brick inside the kiln, air samples were collected for chlorine, sulfur dioxide, inorganic acid, ozone, and dust. After the rebricking was completed and all the workers had exited the kiln, its electrostatic precipitator was reduced to half power and the induced-draft (ID) fan was turned off to recreate conditions present during illness episodes. Chlorine, inorganic acid, and ozone were not detected, and only trace concentrations of sulfur dioxide were detected while workers were inside the kiln. However, when conditions present during previous episodes were recreated, the bleach-like odor was soon evident. Chlorine was not detected, but 0.09 to 0.11 ppm of ozone was measured at the discharge end of the kiln, and 4.5 ppm was measured at the inlet end. Within a half hour after the electrostatic precipitator was turned off and the ID fan was turned on, the ozone concentrations decreased to background levels of 0.02-0.03 ppm. Somewhat lower ozone exposures may have occurred during previous kiln maintenance operations due to more open access portals, but previous episodes of eye and respiratory irritation were probably caused when ozone, generated by the electrostatic precipitator, back-drafted into the kiln after the ID fan was turned off.

  15. Amino acids regulate transgene expression in MDCK cells.

    PubMed

    Torrente, Marta; Guetg, Adriano; Sass, Jörn Oliver; Arps, Lisa; Ruckstuhl, Lisa; Camargo, Simone M R; Verrey, François

    2014-01-01

    Gene expression and cell growth rely on the intracellular concentration of amino acids, which in metazoans depends on extracellular amino acid availability and transmembrane transport. To investigate the impact of extracellular amino acid concentrations on the expression of a concentrative amino acid transporter, we overexpressed the main kidney proximal tubule luminal neutral amino acid transporter B0AT1-collectrin (SLC6A19-TMEM27) in MDCK cell epithelia. Exogenously expressed proteins co-localized at the luminal membrane and mediated neutral amino acid uptake. However, the transgenes were lost over few cell culture passages. In contrast, the expression of a control transgene remained stable. To test whether this loss was due to inappropriately high amino acid uptake, freshly transduced MDCK cell lines were cultivated either with physiological amounts of amino acids or with the high concentration found in standard cell culture media. Expression of exogenous transporters was unaffected by physiological amino acid concentration in the media. Interestingly, mycoplasma infection resulted in a significant increase in transgene expression and correlated with the rapid metabolism of L-arginine. However, L-arginine metabolites were shown to play no role in transgene expression. In contrast, activation of the GCN2 pathway revealed by an increase in eIF2α phosphorylation may trigger transgene derepression. Taken together, high extracellular amino acid concentration provided by cell culture media appears to inhibit the constitutive expression of concentrative amino acid transporters whereas L-arginine depletion by mycoplasma induces the expression of transgenes possibly via stimulation of the GCN2 pathway.

  16. Amino Acids Regulate Transgene Expression in MDCK Cells

    PubMed Central

    Torrente, Marta; Guetg, Adriano; Sass, Jörn Oliver; Arps, Lisa; Ruckstuhl, Lisa; Camargo, Simone M. R.; Verrey, François

    2014-01-01

    Gene expression and cell growth rely on the intracellular concentration of amino acids, which in metazoans depends on extracellular amino acid availability and transmembrane transport. To investigate the impact of extracellular amino acid concentrations on the expression of a concentrative amino acid transporter, we overexpressed the main kidney proximal tubule luminal neutral amino acid transporter B0AT1-collectrin (SLC6A19-TMEM27) in MDCK cell epithelia. Exogenously expressed proteins co-localized at the luminal membrane and mediated neutral amino acid uptake. However, the transgenes were lost over few cell culture passages. In contrast, the expression of a control transgene remained stable. To test whether this loss was due to inappropriately high amino acid uptake, freshly transduced MDCK cell lines were cultivated either with physiological amounts of amino acids or with the high concentration found in standard cell culture media. Expression of exogenous transporters was unaffected by physiological amino acid concentration in the media. Interestingly, mycoplasma infection resulted in a significant increase in transgene expression and correlated with the rapid metabolism of L-arginine. However, L-arginine metabolites were shown to play no role in transgene expression. In contrast, activation of the GCN2 pathway revealed by an increase in eIF2α phosphorylation may trigger transgene derepression. Taken together, high extracellular amino acid concentration provided by cell culture media appears to inhibit the constitutive expression of concentrative amino acid transporters whereas L-arginine depletion by mycoplasma induces the expression of transgenes possibly via stimulation of the GCN2 pathway. PMID:24797296

  17. Saturated fatty acids regulate retinoic acid signalling and suppress tumorigenesis by targeting fatty acid-binding protein 5.

    PubMed

    Levi, Liraz; Wang, Zeneng; Doud, Mary Kathryn; Hazen, Stanley L; Noy, Noa

    2015-11-23

    Long chain fatty acids (LCFA) serve as energy sources, components of cell membranes and precursors for signalling molecules. Here we show that these biological compounds also regulate gene expression and that they do so by controlling the transcriptional activities of the retinoic acid (RA)-activated nuclear receptors RAR and PPARβ/δ. The data indicate that these activities of LCFA are mediated by FABP5, which delivers ligands from the cytosol to nuclear PPARβ/δ. Both saturated and unsaturated LCFA (SLCFA, ULCFA) bind to FABP5, thereby displacing RA and diverting it to RAR. However, while SLCFA inhibit, ULCFA activate the FABP5/PPARβ/δ pathway. We show further that, by concomitantly promoting the activation of RAR and inhibiting the activation of PPARβ/δ, SLCFA suppress the oncogenic properties of FABP5-expressing carcinoma cells in cultured cells and in vivo. The observations suggest that compounds that inhibit FABP5 may constitute a new class of drugs for therapy of certain types of cancer.

  18. Saturated fatty-acids regulate retinoic acid signaling and suppress tumorigenesis by targeting fatty-acid-binding protein 5

    PubMed Central

    Levi, Liraz; Wang, Zeneng; Doud, Mary Kathryn; Hazen, Stanley L.; Noy, Noa

    2015-01-01

    Long chain fatty acids (LCFA) serve as energy sources, components of cell membranes, and precursors for signalling molecules. Here we show that these biological compounds also regulate gene expression and that they do so by controlling the transcriptional activities of the retinoic acid (RA)-activated nuclear receptors RAR and PPARβ/δ. The data indicate that these activities of LCFA are mediated by FABP5 which delivers ligands from the cytosol to nuclear PPARβ/δ. Both saturated and unsaturated LCFA (SLCFA, ULCFA) bind to FABP5, thereby displacing RA and diverting it to RAR. However, while SLCFA inhibit, ULCFA activate the FABP5/PPARβ/δ pathway. We show further that, by concomitantly promoting activation of RAR and inhibiting the activation of PPARβ/δ, SLCFA suppress the oncogenic properties of FABP5-expressing carcinoma cells in cultured cells and in vivo. The observations suggest that compounds that inhibit FABP5 may constitute a new class of drugs for therapy of certain types of cancer. PMID:26592976

  19. What is the Ultimate Goal in Acid-Base Regulation?

    ERIC Educational Resources Information Center

    Balakrishnan, Selvakumar; Gopalakrishnan, Maya; Alagesan, Murali; Prakash, E. Sankaranarayanan

    2007-01-01

    It is common to see chapters on acid-base physiology state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial PCO [subscript 2] (Pa[subscript CO[subscript 2

  20. What is the Ultimate Goal in Acid-Base Regulation?

    ERIC Educational Resources Information Center

    Balakrishnan, Selvakumar; Gopalakrishnan, Maya; Alagesan, Murali; Prakash, E. Sankaranarayanan

    2007-01-01

    It is common to see chapters on acid-base physiology state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial PCO [subscript 2] (Pa[subscript CO[subscript 2

  1. Regulation of the Omega-3 Fatty Acid Biosynthetic Pathway in Atlantic Salmon Hepatocytes

    PubMed Central

    Ruyter, Bente; Berge, Gerd Marit; Sun, Yajing; Østbye, Tone-Kari Knutsdatter

    2016-01-01

    Limited availability of the n-3 fatty acids EPA and DHA have led to an interest in better understanding of the n-3 biosynthetic pathway and its regulation. The biosynthesis of alpha-linolenic acid to EPA and DHA involves several complex reaction steps including desaturation-, elongation- and peroxisomal beta-oxidation enzymes. The aims of the present experiments were to gain more knowledge on how this biosynthesis is regulated over time by different doses and fatty acid combinations. Hepatocytes isolated from salmon were incubated with various levels and combinations of oleic acid, EPA and DHA. Oleic acid led to a higher expression of the Δ6 fatty acid desaturase (fad) genes Δ6fad_a, Δ6fad_b, Δ6fad_c and the elongase genes elovl2 compared with cells cultured in medium enriched with DHA. Further, the study showed rhythmic variations in expression over time. Levels were reached where a further increase in specific fatty acids given to the cells not stimulated the conversion further. The gene expression of Δ6fad_a_and Δ6fad_b responded similar to fatty acid treatment, suggesting a co-regulation of these genes, whereas Δ5fad and Δ6fad_c showed a different regulation pattern. EPA and DHA induced different gene expression patterns, especially of Δ6fad_a. Addition of radiolabelled alpha-linolenic acid to the hepatocytes confirmed a higher degree of elongation and desaturation in cells treated with oleic acid compared to cells treated with DHA. This study suggests a complex regulation of the conversion process of n-3 fatty acids. Several factors, such as that the various gene copies are differently regulated, the gene expression show rhythmic variations and gene expression only affected to a certain level, determines when you get the maximum conversion of the beneficial n-3 fatty acids. PMID:27973547

  2. Hyaluronan Signaling during Ozone-Induced Lung Injury Requires TLR4, MyD88, and TIRAP

    PubMed Central

    Li, Zhuowei; Potts-Kant, Erin N.; Garantziotis, Stavros; Foster, W. Michael; Hollingsworth, John W.

    2011-01-01

    Ozone exposure is associated with exacerbation of reactive airways disease. We have previously reported that the damage-associated molecular pattern, hyaluronan, is required for the complete biological response to ambient ozone and that hyaluronan fragments signal through toll-like receptor 4 (TLR4). In this study, we further investigated the role of TLR4 adaptors in ozone–induced airway hyperresponsiveness (AHR) and the direct response to hyaluronan fragments (HA). Using a murine model of AHR, C57BL/6J, TLR4−/−, MyD88−/−, and TIRAP−/− mice were characterized for AHR after exposure to either ozone (1 ppm×3 h) or HA fragments. Animals were characterized for AHR with methacholine challenge, cellular inflammation, lung injury, and production of pro-inflammatory cytokines. Ozone-exposed C57BL/6J mice developed cellular inflammation, lung injury, pro-inflammatory cytokines, and AHR, while mice deficient in TLR4, MyD88 or TIRAP demonstrated both reduced AHR and reduced levels of pro-inflammatory cytokines including TNFα, IL-1β, MCP-1, IL-6 and KC. The level of hyaluronan was increased after inhalation of ozone in each strain of mice. Direct challenge of mice to hyaluronan resulted in AHR in C57BL/6J mice, but not in TLR4−/−, MyD88−/−, or TIRAP−/− mice. HA-induced cytokine production in wild-type mice was significantly reduced in TLR4−/−, MyD88−/−, or TIRAP−/− mice. In conclusion, our findings support that ozone-induced airway hyperresponsiveness is dependent on the HA-TLR4-MyD88-TIRAP signaling pathway. PMID:22073274

  3. Ozone-induced dissociation on a modified tandem linear ion-trap: observations of different reactivity for isomeric lipids.

    PubMed

    Poad, Berwyck L J; Pham, Huong T; Thomas, Michael C; Nealon, Jessica R; Campbell, J Larry; Mitchell, Todd W; Blanksby, Stephen J

    2010-12-01

    Ozone-induced dissociation (OzID) exploits the gas-phase reaction between mass-selected lipid ions and ozone vapor to determine the position(s) of unsaturation. In this contribution, we describe the modification of a tandem linear ion-trap mass spectrometer specifically for OzID analyses wherein ozone vapor is supplied to the collision cell. This instrumental configuration provides spatial separation between mass-selection, the ozonolysis reaction, and mass-analysis steps in the OzID process and thus delivers significant enhancements in speed and sensitivity (ca. 30-fold). These improvements allow spectra revealing the double-bond position(s) within unsaturated lipids to be acquired within 1 s: significantly enhancing the utility of OzID in high-throughput lipidomic protocols. The stable ozone concentration afforded by this modified instrument also allows direct comparison of relative reactivity of isomeric lipids and reveals reactivity trends related to (1) double-bond position, (2) substitution position on the glycerol backbone, and (3) stereochemistry. For cis- and trans-isomers, differences were also observed in the branching ratio of product ions arising from the gas-phase ozonolysis reaction, suggesting that relative ion abundances could be exploited as markers for double-bond geometry. Additional activation energy applied to mass-selected lipid ions during injection into the collision cell (with ozone present) was found to yield spectra containing both OzID and classical-CID fragment ions. This combination CID-OzID acquisition on an ostensibly simple monounsaturated phosphatidylcholine within a cow brain lipid extract provided evidence for up to four structurally distinct phospholipids differing in both double-bond position and sn-substitution.

  4. Serum amyloid A: an ozone-induced circulating factor with potentially important functions in the lung-brain axis.

    PubMed

    Erickson, Michelle A; Jude, Joseph; Zhao, Hengjiang; Rhea, Elizabeth M; Salameh, Therese S; Jester, William; Pu, Shelley; Harrowitz, Jenna; Nguyen, Ngan; Banks, William A; Panettieri, Reynold A; Jordan-Sciutto, Kelly L

    2017-09-01

    Accumulating evidence suggests that O3 exposure may contribute to CNS dysfunction. Here, we posit that inflammatory and acute-phase proteins in the circulation increase after O3 exposure and systemically convey signals of O3 exposure to the CNS. To model acute O3 exposure, female Balb/c mice were exposed to 3 ppm O3 or forced air for 2 h and were studied after 6 or 24 h. Of 23 cytokines and chemokines, only KC/CXCL1 was increased in blood 6 h after O3 exposure. The acute-phase protein serum amyloid A (A-SAA) was significantly increased by 24 h, whereas C-reactive protein was unchanged. A-SAA in blood correlated with total leukocytes, macrophages, and neutrophils in bronchoalveolar lavage from O3-exposed mice. A-SAA mRNA and protein were increased in the liver. We found that both isoforms of A-SAA completely crossed the intact blood-brain barrier, although the rate of SAA2.1 influx was approximately 5 times faster than that of SAA1.1. Finally, A-SAA protein, but not mRNA, was increased in the CNS 24 h post-O3 exposure. Our findings suggest that A-SAA is functionally linked to pulmonary inflammation in our O3 exposure model and that A-SAA could be an important systemic signal of O3 exposure to the CNS.-Erickson, M. A., Jude, J., Zhao, H., Rhea, E. M., Salameh, T. S., Jester, W., Pu, S., Harrowitz, J., Nguyen, N., Banks, W. A., Panettieri, R. A., Jr., Jordan-Sciutto, K. L. Serum amyloid A: an ozone-induced circulating factor with potentially important functions in the lung-brain axis. © FASEB.

  5. Simultaneous detection of gastric acid and histamine release to unravel the regulation of acid secretion from the guinea pig stomach.

    PubMed

    Bitziou, Eleni; Patel, Bhavik Anil

    2012-08-01

    Gastric acid secretion is regulated by three primary components that activate the parietal cell: histamine, gastrin, and acetylcholine (ACh). Although much is known about these regulatory components individually, little is known on the interplay of these multiple activators and the degree of regulation they pose on the gastric acid secretion mechanism. We utilized a novel dual-sensing approach, where an iridium oxide sensor was used to monitor pH and a boron-doped diamond electrode was used for the detection of histamine from in vitro guinea pig stomach mucosal sections. Under basal conditions, gastrin was shown to be the main regulatory component of the total acid secretion and directly activated the parietal cell rather than by mediating gastric acid secretion through the release of histamine from the enterochromaffin-like cell, although both pathways were active. Under stimulated conditions with ACh, the gastrin and histamine components of the total acid secretion were not altered compared with levels observed under basal conditions, suggestive that ACh had no direct effect on the enterochromaffin-like cell and G cell. These data identify a new unique approach to investigate the regulation pathways active during acid secretion and the degree that they are utilized to drive total gastric acid secretion. The findings of this study will enhance our understanding on how these signaling mechanisms vary under pathophysiology or therapeutic management.

  6. Regulation of myocardial amino acid balance in the conscious dog.

    PubMed Central

    Schwartz, R G; Barrett, E J; Francis, C K; Jacob, R; Zaret, B L

    1985-01-01

    The effects in vivo of physiologic increases in insulin and amino acids on myocardial amino acid balance were evaluated in conscious dogs. Arterial and coronary sinus concentrations of amino acids and coronary blood flow were measured during a 30-min basal and a 100-min experimental period employing three protocols: euglycemic insulin clamp (plasma insulin equaled 70 +/- 11 microU/ml, n = 6); euglycemic insulin clamp during amino acid infusion (plasma insulin equaled 89 +/- 12 microU/ml, n = 6); and suppression of insulin with somatostatin during amino acid infusion (plasma insulin equaled 15 +/- 4 microU/ml, n = 6). Basally, only leucine and isoleucine were removed significantly by myocardium (net branched chain amino acid [BCAA] uptake equaled 0.5 +/- 0.2 mumol/min), while glycine, alanine, and glutamine were released. Glutamine demonstrated the highest net myocardial production (1.6 +/- 0.2 mumol/min). No net exchange was seen for valine, phenylalanine, tyrosine, cysteine, methionine, glutamate, asparagine, serine, threonine, taurine, and aspartate. In group I, hyperinsulinemia caused a decline of all plasma amino acids except alanine; alanine balance switched from release to an uptake of 0.6 +/- 0.4 mumol/min (P less than 0.05), while the myocardial balance of other amino acids was unchanged. In group II, amino acid concentrations rose, and were accompanied by a marked rise in myocardial BCAA uptake (0.4 +/- 0.1-2.6 +/- 0.3 mumol/min, P less than 0.001). Uptake of alanine was again stimulated (0.9 +/- 0.3 mumol/min, P less than 0.01), while glutamine production was unchanged (1.3 +/- 0.4 vs. 1.6 +/- 0.3 mumol/min). In group III, there was a 4-5-fold increase in the plasma concentration of the infused amino acids, accompanied by marked stimulation in uptake of only BCAA (6.8 +/- 0.7 mumol/min). Myocardial glutamine production was unchanged (1.9 +/- 0.4-1.3 +/- 0.7 mumol/min). Within the three experimental groups there were highly significant linear correlations

  7. Baseline Chromatin Modification Levels May Predict Interindividual Variability in Ozone-Induced Gene Expression

    PubMed Central

    McCullough, Shaun D.; Bowers, Emma C.; On, Doan M.; Morgan, David S.; Dailey, Lisa A.; Hines, Ronald N.; Devlin, Robert B.; Diaz-Sanchez, David

    2016-01-01

    Traditional toxicological paradigms have relied on factors such as age, genotype, and disease status to explain variability in responsiveness to toxicant exposure; however, these are neither sufficient to faithfully identify differentially responsive individuals nor are they modifiable factors that can be leveraged to mitigate the exposure effects. Unlike these factors, the epigenome is dynamic and shaped by an individual’s environment. We sought to determine whether baseline levels of specific chromatin modifications correlated with the interindividual variability in their ozone (O3)-mediated induction in an air–liquid interface model using primary human bronchial epithelial cells from a panel of 11 donors. We characterized the relationship between the baseline abundance of 6 epigenetic markers with established roles as key regulators of gene expression—histone H3 lysine 4 trimethylation (H3K4me3), H3K27 acetylation (H3K27ac), pan-acetyl H4 (H4ac), histone H3K27 di/trimethylation (H3K27me2/3), unmodified H3, and 5-hydroxymethylcytosine (5-hmC)—and the variability in the O3-induced expression of IL-8, IL-6, COX2, and HMOX1. Baseline levels of H3K4me3, H3K27me2/3, and 5-hmC, but not H3K27ac, H4ac, and total H3, correlated with the interindividual variability in O3-mediated induction of HMOX1 and COX2. In contrast, none of the chromatin modifications that we examined correlated with the induction of IL-8 and IL-6. From these findings, we propose an “epigenetic seed and soil” model in which chromatin modification states between individuals differ in the relative abundance of specific modifications (the “soil”) that govern how receptive the gene is to toxicant-mediated cellular signals (the “seed”) and thus regulate the magnitude of exposure-related gene induction. PMID:26719369

  8. Indomethacin pretreatment reduces ozone-induced pulmonary function decrements in human subjects

    SciTech Connect

    Schelegle, E.S.; Adams, W.C.; Siefkin, A.D.

    1987-12-01

    We studied whether O/sub 3/-induced pulmonary function decrements could be inhibited by the prostaglandin synthetase inhibitor, indomethacin, in healthy human subjects. Fourteen college-age males completed six 1-h exposure protocols consisting of no drug, placebo, and indomethacin (Indocin SR 75 mg every 12 h for 5 days) pretreatments, with filtered air and O/sub 3/ (0.35 ppm) exposures within each pretreatment. Pretreatments were delivered weekly in random order in a double-blind fashion. Ozone and filtered air exposures, separated by 72 h, were delivered in random order in a single-blind fashion. Exposures consisted of 1-h exercise on a bicycle ergometer with work loads set to elicit a mean minute ventilation of 60 L/min. Statistical analysis revealed significant (p less than 0.05) across pretreatment effects for FVC and FEV1, with no drug versus indomethacin and placebo versus indomethacin comparisons being significant. These findings suggest that cyclooxygenase products of arachidonic acid, which are sensitive to indomethacin inhibition, play a prominent role in the development of pulmonary function decrements consequent to acute O/sub 3/ exposure.

  9. Amino acids allosterically regulate the thiamine diphosphate-dependent alpha-keto acid decarboxylase from Mycobacterium tuberculosis.

    PubMed

    Werther, Tobias; Spinka, Michael; Tittmann, Kai; Schütz, Anja; Golbik, Ralph; Mrestani-Klaus, Carmen; Hübner, Gerhard; König, Stephan

    2008-02-29

    The gene rv0853c from Mycobacterium tuberculosis strain H37Rv codes for a thiamine diphosphate-dependent alpha-keto acid decarboxylase (MtKDC), an enzyme involved in the amino acid degradation via the Ehrlich pathway. Steady state kinetic experiments were performed to determine the substrate specificity of MtKDC. The mycobacterial enzyme was found to convert a broad spectrum of branched-chain and aromatic alpha-keto acids. Stopped-flow kinetics showed that MtKDC is allosterically activated by alpha-keto acids. Even more, we demonstrate that also amino acids are potent activators of this thiamine diphosphate-dependent enzyme. Thus, metabolic flow through the Ehrlich pathway can be directly regulated at the decarboxylation step. The influence of amino acids on MtKDC catalysis was investigated, and implications for other thiamine diphosphate-dependent enzymes are discussed.

  10. The LysR-type regulator LeuO regulates the acid tolerance response in Vibrio cholerae

    PubMed Central

    Ante, Vanessa M.; Bina, X. Renee

    2015-01-01

    Vibrio cholerae is a neutrophilic enteric pathogen that is extremely sensitive to acid. As V. cholerae passages through the host gastrointestinal tract it is exposed to a variety of environmental stresses including low pH and volatile fatty acids. Exposure to acidic environments induces expression of the V. cholerae acid tolerance response. A key component of the acid tolerance response is the cad system, which is encoded by cadC and the cadBA operon. CadB is a lysine/cadaverine antiporter and CadA is a lysine decarboxylase and these function together to counter low intracellular and extracellular pH. CadC is a membrane-associated transcription factor that activates cadBA expression in response to acidic conditions. Herein we investigated the role of the LysR-type transcriptional regulator LeuO in the V. cholerae acid tolerance response. Transcriptional reporter assays revealed that leuO expression repressed cadC transcription, indicating that LeuO was a cadC repressor. Consistent with this, leuO expression was inversely linked to lysine decarboxylase production and leuO overexpression resulted in increased sensitivity to organic acids. Overexpression of leuO in a cadA mutant potentiated killing by organic acids, suggesting that the function of leuO in the acid tolerance response extended beyond its regulation of the cad system. Collectively, these studies have identified a new physiological role for LeuO in V. cholerae acid tolerance. PMID:26424466

  11. Increased anion channel activity is an unavoidable event in ozone-induced programmed cell death.

    PubMed

    Kadono, Takashi; Tran, Daniel; Errakhi, Rafik; Hiramatsu, Takuya; Meimoun, Patrice; Briand, Joël; Iwaya-Inoue, Mari; Kawano, Tomonori; Bouteau, François

    2010-10-13

    Ozone is a major secondary air pollutant often reaching high concentrations in urban areas under strong daylight, high temperature and stagnant high-pressure systems. Ozone in the troposphere is a pollutant that is harmful to the plant. By exposing cells to a strong pulse of ozonized air, an acute cell death was observed in suspension cells of Arabidopsis thaliana used as a model. We demonstrated that O(3) treatment induced the activation of a plasma membrane anion channel that is an early prerequisite of O(3)-induced cell death in A. thaliana. Our data further suggest interplay of anion channel activation with well known plant responses to O(3), Ca(2+) influx and NADPH-oxidase generated reactive oxygen species (ROS) in mediating the oxidative cell death. This interplay might be fuelled by several mechanisms in addition to the direct ROS generation by O(3); namely, H(2)O(2) generation by salicylic and abscisic acids. Anion channel activation was also shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during programmed cell death. Collectively, our data indicate that anion efflux is an early key component of morphological and biochemical events leading to O(3)-induced programmed cell death. Because ion channels and more specifically anion channels assume a crucial position in cells, an understanding about the underlying role(s) for ion channels in the signalling pathway leading to programmed cell death is a subject that warrants future investigation.

  12. Ozone-induced inflammation in the lower airways of human subjects

    SciTech Connect

    Koren, H.S.; Devlin, R.B.; Graham, D.E.; Mann, R.; McGee, M.P.; Horstman, D.H.; Kozumbo, W.J.; Becker, S.; House, D.E.; McDonnell, W.F.

    1989-02-01

    Although ozone (O3) has been shown to induce inflammation in the lungs of animals, very little is known about its inflammatory effects on humans. In this study, 11 healthy nonsmoking men, 18 to 35 yr of age (mean, 25.4 +/- 3.5), were exposed once to 0.4 ppm O3 and once to filtered air for 2 h with intermittent exercise. Eighteen hours later, bronchoalveolar lavage (BAL) was performed and the cells and fluid were analyzed for various indicators of inflammation. There was an 8.2-fold increase in the percentage of polymorphonuclear leukocytes (PMN) in the total cell population, and a small but significant decrease in the percentage of macrophages after exposure to O3. Immunoreactive neutrophil elastase often associated with inflammation and lung damage increased by 3.8-fold in the fluid while its activity increased 20.6-fold in the lavaged cells. A 2-fold increase in the levels of protein, albumin, and IgG suggested increased vascular permeability of the lung. Several biochemical markers that could act as chemotactic or regulatory factors in an inflammatory response were examined in the BAL fluid (BALF). The level of complement fragment C3 alpha was increased by 1.7-fold. The chemotactic leukotriene B4 was unchanged while prostaglandin E2 increased 2-fold. In contrast, three enzyme systems of phagocytes with potentially damaging effects on tissues and microbes, namely, NADPH-oxidase and the lysosomal enzymes acid phosphatase and beta-glucuronidase, were increased neither in the lavaged fluid nor cells. In addition, the amounts of fibrogenic-related molecules were assessed in BALF.

  13. Regulation of uterine and umbilical amino acid uptakes by maternal amino acid concentrations.

    PubMed

    Thureen, P J; Anderson, S M; Hay, W W

    2000-09-01

    We tested the hypothesis that decreased fetal amino acid (AA) supply, produced by maternal hypoaminoacidemia (low AA) during hyperglycemia (HG), is reversible with maternal AA infusion and regulates fetal insulin concentration ([I]). We measured net uterine and umbilical AA uptakes during maternal HG/low AA concentration ([AA]) and after maternal intravenous infusion of a mixed AA solution. After 5 days HG, all maternal [AA] except glycine were decreased >50%, particularly essential [AA] (P < 0.00005). Most fetal [AA] also were decreased, especially branched-chain AA (P < 0.001). Maternal AA infusion increased net uterine uptakes of Val, Leu, Ile, Met, and Ser and net umbilical uptakes of Val, Leu, Ile, Met, Phe, and Arg but did not change net uteroplacental uptake of any AA. Fetal [I] increased 55 +/- 14%, P < 0.001, with correction of fetal [AA], despite the lack of change in fetal glucose concentration. Thus generalized maternal hypoaminoacidemia decreases uterine and umbilical uptakes of primarily the essential AA and decreases fetal branched-chain [AA]. These changes are reversed with correction of maternal [AA], which also increases fetal [I].

  14. Transcription factor networks regulating hepatic fatty acid metabolism.

    PubMed

    Karagianni, Panagiota; Talianidis, Iannis

    2015-01-01

    Tight regulation of lipid levels is critical for cellular and organismal homeostasis, not only in terms of energy utilization and storage, but also to prevent potential toxicity. The liver utilizes a set of hepatic transcription factors to regulate the expression of genes implicated in all aspects of lipid metabolism including catabolism, transport, and synthesis. In this article, we will review the main transcriptional mechanisms regulating the expression of genes involved in hepatic lipid metabolism. The principal regulatory pathways are composed of simple modules of transcription factor crosstalks, which correspond to building blocks of more complex regulatory networks. These transcriptional networks contribute to the regulation of proper lipid homeostasis in parallel to posttranslational mechanisms and end product-mediated modulation of lipid metabolizing enzymes. This article is part of a Special Issue entitled Linking transcription to physiology in lipodomics. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Fatty acid unsaturation, mobilization, and regulation in the response of plants to stress.

    PubMed

    Upchurch, Robert G

    2008-06-01

    Stress acclimating plants respond to abiotic and biotic stress by remodeling membrane fluidity and by releasing alpha-linolenic (18:3) from membrane lipids. The modification of membrane fluidity is mediated by changes in unsaturated fatty acid levels, a function provided in part by the regulated activity of fatty acid desaturases. Adjustment of membrane fluidity maintains an environment suitable for the function of critical integral proteins during stress. alpha-Linolenic acid, released from membrane lipid by regulated lipase activity, is the precursor molecule for phyto-oxylipin biosynthesis. The modulation of chloroplast oleic acid (18:1) levels is central to the normal expression of defense responses to pathogens in Arabidopsis. Oleic (18:1) and linolenic (18:2) acid levels, in part, regulate development, seed colonization, and mycotoxin production by Aspergillus spp.

  16. Regulating the Skin Permeation Rate of Escitalopram by Ion-pair Formation with Organic Acids.

    PubMed

    Song, Tian; Quan, Peng; Xiang, Rongwu; Fang, Liang

    2016-12-01

    In order to regulate the skin permeation rate (flux) of escitalopram (ESP), ion-pair strategy was used in our work. Five organic acids with different physicochemical properties, benzoic acid (BA), ibuprofen (IB), salicylic acid (SA), benzenesulfonic acid (BSA), and p-aminobenzoic acid (PABA), were employed as counter-ions to regulate the permeation rate of ESP across the rabbit abdominal skin in vitro. The interaction between ESP and organic acids was characterized by FTIR and (13)C NMR spectroscopy. Results showed that all organic acids investigated in this study performed a controlling effect on ESP flux. To further analyze the factors concerned with the permeation capability of ESP-acid complex, a multiple linear regression model was used. It is concluded that the steady-state flux (J) of ESP-acid complexes had a positive correlation with log K o/w (the n-octanol/water partition coefficient of ion-pair complex) and pK a (the acidity of organic acid counter-ion), but a negative correlation with MW (the molecular weight of ion-pair complex). The logK o/w of ion-pair complex is the primary one in all the factors that influence the skin permeation rate of ESP. The results demonstrated that organic acid with appropriate physicochemical properties can be considered as suitable candidate for the transdermal drug delivery of escitalopram.

  17. γδ T Cells Are Required for M2 Macrophage Polarization and Resolution of Ozone-Induced Pulmonary Inflammation in Mice.

    PubMed

    Mathews, Joel A; Kasahara, David I; Ribeiro, Luiza; Wurmbrand, Allison P; Ninin, Fernanda M C; Shore, Stephanie A

    2015-01-01

    We examined the role of γδ T cells in the induction of alternatively activated M2 macrophages and the resolution of inflammation after ozone exposure. Wildtype (WT) mice and mice deficient in γδ T cells (TCRδ-/- mice) were exposed to air or to ozone (0.3 ppm for up to 72h) and euthanized immediately or 1, 3, or 5 days after cessation of exposure. In WT mice, M2 macrophages accumulated in the lungs over the course of ozone exposure. Pulmonary mRNA abundance of the M2 genes, Arg1, Retnla, and Clec10a, also increased after ozone. In contrast, no evidence of M2 polarization was observed in TCRδ-/- mice. WT but not TCRδ-/- mice expressed the M2c polarizing cytokine, IL-17A, after ozone exposure and WT mice treated with an IL-17A neutralizing antibody exhibited attenuated ozone-induced M2 gene expression. In WT mice, ozone-induced increases in bronchoalveolar lavage neutrophils and macrophages resolved quickly after cessation of ozone exposure returning to air exposed levels within 3 days. However, lack of M2 macrophages in TCRδ-/- mice was associated with delayed clearance of inflammatory cells after cessation of ozone and increased accumulation of apoptotic macrophages in the lungs. Delayed restoration of normal lung architecture was also observed in TCRδ-/- mice. In summary, our data indicate that γδ T cells are required for the resolution of ozone-induced inflammation, likely because γδ T cells, through their secretion of IL-17A, contribute to changes in macrophage polarization that promote clearance of apoptotic cells.

  18. Regulation of bile acid synthesis in rat hepatocyte monolayer cultures

    SciTech Connect

    Kubaska, W.M.

    1986-01-01

    Primary hepatocyte monolayer cultures (PHC) were prepared and incubated in serum free media. Cells from a cholestyramine fed rat converted exogenous (/sup 14/C)-cholesterol into (/sup 14/C)-bile acids at a 3-fold greater rate than rats fed a normal diet. PHC synthesize bile acids (BA) at a rate of approximately 0.06 ..mu..g/mg protein/h. The major bile acid composition, as determined by GLC, was ..beta..-muricholic acid (BMC) and cholic acid (CA) in a 3:1 ratio, respectively. PHC rapidly converted free BA and BA intermediates into taurine conjugated trihydroxy-BA up to 87h after plating. 3-Hydroxy-3-methylglutaryl-coenzyme A-reductase activity assayed in microsomes prepared from PHC, decreased during the initial 48h, then remained constant. Cholesterol 7..cap alpha..-hydroxylase activity decreased during the initial 48h, then increased during the next 48h. This occurred while whole cells produced BA at a linear rate. The effect of individual BA on bile acid synthesis (BAS) was also studied. Relative rates of BAS were measured as the conversion of (/sup 14/C)-cholesterol into (/sup 14/C)-BA. BA combinations were tested in order to simulate the composition of the enterohepatic circulation. The addition of TCA (525 ..mu..M) plus TCDCA (80..mu..M), in concentrations which greatly exceed the concentration of BA (60..mu..M) in rate portal blood, failed to inhibit BAS. BA plus phospholipid and/or cholesterol also did not inhibit BAS. Surprisingly, crude rat bile with a final concentration comparable to those in the synthetic mix inhibited (/sup 14/C)-cholesterol conversion into (/sup 14/C)-BA.

  19. Biogas Production on Demand Regulated by Butyric Acid Addition

    NASA Astrophysics Data System (ADS)

    Kasper, K.; Schiffels, J.; Krafft, S.; Kuperjans, I.; Elbers, G.; Selmer, T.

    2016-03-01

    Investigating effects of volatile fatty acids on the biogas process it was observed that butyric acid can be used for transient stimulation of the methane production in biogas plants operating with low energy substrates like cattle manure. Upon addition of butyrate the methane output of the reactors doubled within 24 h and reached almost 3-times higher methane yields within 3-4 days. Butyrate was quantitatively eliminated and the reactors returned to the original productivity state within 3 days when application of butyrate was stopped. The opportunity to use butyrate feeding for increased biogas production on demand is discussed.

  20. Insulin Signaling Regulates Fatty Acid Catabolism at the Level of CoA Activation

    PubMed Central

    Xu, Xiaojun; Gopalacharyulu, Peddinti; Seppänen-Laakso, Tuulikki; Ruskeepää, Anna-Liisa; Aye, Cho Cho; Carson, Brian P.; Mora, Silvia; Orešič, Matej; Teleman, Aurelio A.

    2012-01-01

    The insulin/IGF signaling pathway is a highly conserved regulator of metabolism in flies and mammals, regulating multiple physiological functions including lipid metabolism. Although insulin signaling is known to regulate the activity of a number of enzymes in metabolic pathways, a comprehensive understanding of how the insulin signaling pathway regulates metabolic pathways is still lacking. Accepted knowledge suggests the key regulated step in triglyceride (TAG) catabolism is the release of fatty acids from TAG via the action of lipases. We show here that an additional, important regulated step is the activation of fatty acids for beta-oxidation via Acyl Co-A synthetases (ACS). We identify pudgy as an ACS that is transcriptionally regulated by direct FOXO action in Drosophila. Increasing or reducing pudgy expression in vivo causes a decrease or increase in organismal TAG levels respectively, indicating that pudgy expression levels are important for proper lipid homeostasis. We show that multiple ACSs are also transcriptionally regulated by insulin signaling in mammalian cells. In sum, we identify fatty acid activation onto CoA as an important, regulated step in triglyceride catabolism, and we identify a mechanistic link through which insulin regulates lipid homeostasis. PMID:22275878

  1. Regulation of Arabidopsis thaliana seed dormancy and germination by 12-oxo-phytodienoic acid.

    PubMed

    Dave, Anuja; Vaistij, Fabián E; Gilday, Alison D; Penfield, Steven D; Graham, Ian A

    2016-04-01

    We previously demonstrated that the oxylipin 12-oxo-phytodienoic acid (OPDA) acts along with abscisic acid to regulate seed germination in Arabidopsis thaliana, but the mechanistic details of this synergistic interaction remain to be elucidated. Here, we show that OPDA acts through the germination inhibition effects of abscisic acid, the abscisic acid-sensing ABI5 protein, and the gibberellin-sensing RGL2 DELLA protein. We further demonstrate that OPDA also acts through another dormancy-promoting factor, MOTHER-OF-FT-AND-TFL1 (MFT). Both abscisic acid and MFT positively feed back into the OPDA pathway by promoting its accumulation. These results confirm the central role of OPDA in regulating seed dormancy and germination in A. thaliana and underline the complexity of interactions between OPDA and other dormancy-promoting factors such as abscisic acid, RGL2, and MFT.

  2. Aspects of the regulation of long-chain fatty acid oxidation in bovine liver

    SciTech Connect

    Jesse, B.W.; Emery, R.S.; Thomas, J.W.

    1986-09-01

    Factors involved in regulation of bovine hepatic fatty acid oxidation were examined using liver slices. Fatty acid oxidation was measured as the conversion of l-(/sup 14/C) palmitate to /sup 14/CO/sub 2/ and total (/sup 14/C) acid-soluble metabolites. Extended (5 to 7 d) fasting of Holstein cows had relatively little effect on palmitate oxidation to acid-soluble metabolites by liver slices, although oxidation to CO/sup 2/ was decreased. Feeding a restricted roughage, high concentrate ration to lactating cows resulted in inhibition of palmitate oxidation. Insulin, glucose, and acetate inhibited palmitate oxidation by bovine liver slices. The authors suggest the regulation of bovine hepatic fatty acid oxidation may be less dependent on hormonally induced alterations in enzyme activity as observed in rat liver and more dependent upon action of rumen fermentation products or their metabolites on enzyme systems involved in fatty acid oxidation.

  3. Regulation of Arabidopsis thaliana seed dormancy and germination by 12-oxo-phytodienoic acid

    PubMed Central

    Dave, Anuja; Vaistij, Fabián E.; Gilday, Alison D.; Penfield, Steven D.; Graham, Ian A.

    2016-01-01

    We previously demonstrated that the oxylipin 12-oxo-phytodienoic acid (OPDA) acts along with abscisic acid to regulate seed germination in Arabidopsis thaliana, but the mechanistic details of this synergistic interaction remain to be elucidated. Here, we show that OPDA acts through the germination inhibition effects of abscisic acid, the abscisic acid-sensing ABI5 protein, and the gibberellin-sensing RGL2 DELLA protein. We further demonstrate that OPDA also acts through another dormancy-promoting factor, MOTHER-OF-FT-AND-TFL1 (MFT). Both abscisic acid and MFT positively feed back into the OPDA pathway by promoting its accumulation. These results confirm the central role of OPDA in regulating seed dormancy and germination in A. thaliana and underline the complexity of interactions between OPDA and other dormancy-promoting factors such as abscisic acid, RGL2, and MFT. PMID:26873978

  4. Observations of ozone-induced foliar injury on black cherry (Prunus serotina, var. capuli) within the Desierto de Los Leones National Park, Mexico City.

    PubMed

    Skelly, J M; Savage, J E; de Bauer, M de L; Alvarado, D

    1997-01-01

    A survey for ozone-induced foliar injury of black cherry was conducted in mid-June 1995 within the Desierto de Los Leones National Park located southwest of Mexico City. Evaluations of the upper and lower tree crowns of 18 trees revealed evidence of significant upper surface stipple, leaf reddening and premature senescence on 72% of the trees. A general survey of an additional 169 trees disclosed that 41% exhibited similar symptoms. A gradient of increasing symptoms with increasing elevation was also evident. For the most part, asymptomatic trees were observed to be situated within well-shaded coves at the lower elevations with very few symptomatic trees present in these areas.

  5. Fatty acids from diet and microbiota regulate energy metabolism

    PubMed Central

    Alcock, Joe; Lin, Henry C.

    2015-01-01

    A high-fat diet and elevated levels of free fatty acids are known risk factors for metabolic syndrome, insulin resistance, and visceral obesity. Although these disease associations are well established, it is unclear how different dietary fats change the risk of insulin resistance and metabolic syndrome. Here, we review emerging evidence that insulin resistance and fat storage are linked to changes in the gut microbiota. The gut microbiota and intestinal barrier function, in turn, are highly influenced by the composition of fat in the diet. We review findings that certain fats (for example, long-chain saturated fatty acids) are associated with dysbiosis, impairment of intestinal barrier function, and metabolic endotoxemia. In contrast, other fatty acids, including short-chain and certain unsaturated fatty acids, protect against dysbiosis and impairment of barrier function caused by other dietary fats. These fats may promote insulin sensitivity by inhibiting metabolic endotoxemia and dysbiosis-driven inflammation. During dysbiosis, the modulation of metabolism by diet and microbiota may represent an adaptive process that compensates for the increased fuel demands of an activated immune system. PMID:27006755

  6. Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells.

    PubMed

    Lajczak, Natalia K; Saint-Criq, Vinciane; O'Dwyer, Aoife M; Perino, Alessia; Adorini, Luciano; Schoonjans, Kristina; Keely, Stephen J

    2017-09-01

    Bile acids and epithelial-derived human β-defensins (HβDs) are known to be important factors in the regulation of colonic mucosal barrier function and inflammation. We hypothesized that bile acids regulate colonic HβD expression and aimed to test this by investigating the effects of deoxycholic acid (DCA) and ursodeoxycholic acid on the expression and release of HβD1 and HβD2 from colonic epithelial cells and mucosal tissues. DCA (10-150 µM) stimulated the release of both HβD1 and HβD2 from epithelial cell monolayers and human colonic mucosal tissue in vitro In contrast, ursodeoxycholic acid (50-200 µM) inhibited both basal and DCA-induced defensin release. Effects of DCA were mimicked by the Takeda GPCR 5 agonist, INT-777 (50 μM), but not by the farnesoid X receptor agonist, GW4064 (10 μM). INT-777 also stimulated colonic HβD1 and HβD2 release from wild-type, but not Takeda GPCR 5(-/-), mice. DCA stimulated phosphorylation of the p65 subunit of NF-κB, an effect that was attenuated by ursodeoxycholic acid, whereas an NF-κB inhibitor, BMS-345541 (25 μM), inhibited DCA-induced HβD2, but not HβD1, release. We conclude that bile acids can differentially regulate colonic epithelial HβD expression and secretion and discuss the implications of our findings for intestinal health and disease.-Lajczak, N. K., Saint-Criq, V., O'Dwyer, A. M., Perino, A., Adorini, L., Schoonjans, K., Keely, S. J. Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells. © FASEB.

  7. Regulatory impact analysis of the proposed acid-rain implementation regulations

    SciTech Connect

    Not Available

    1991-09-16

    This regulatory impact analysis (RIA) was developed in response to Executive Order (EO) 12291, which requires Federal Agencies to assess the costs, benefits, and impacts of all 'major' regulations. In compliance with EO 12291, this RIA assesses costs, benefits and impacts for the important provisions of Title IV. EPA divided its analysis of the Acid Rain Program into two parts. First, EPA analyzed the effects of the statute in the absence of any implementation regulations. In the second part of the analysis, EPA examined a 'regulatory' case that included both the SO2 reductions and the implementation regulations. By comparing costs under the regulatory case to those under the absent regulations case, EPA was able to isolate the incremental savings provided by the regulations. At the same time, by combining the two parts of the analysis, EPA was able to show the total costs imposed by the Acid Rain Program (the statute and the regulations) as a whole.

  8. Obeticholic acid, a selective farnesoid X receptor agonist, regulates bile acid homeostasis in sandwich-cultured human hepatocytes.

    PubMed

    Zhang, Yuanyuan; Jackson, Jonathan P; St Claire, Robert L; Freeman, Kimberly; Brouwer, Kenneth R; Edwards, Jeffrey E

    2017-08-01

    Farnesoid X receptor (FXR) is a master regulator of bile acid homeostasis through transcriptional regulation of genes involved in bile acid synthesis and cellular membrane transport. Impairment of bile acid efflux due to cholangiopathies results in chronic cholestasis leading to abnormal elevation of intrahepatic and systemic bile acid levels. Obeticholic acid (OCA) is a potent and selective FXR agonist that is 100-fold more potent than the endogenous ligand chenodeoxycholic acid (CDCA). The effects of OCA on genes involved in bile acid homeostasis were investigated using sandwich-cultured human hepatocytes. Gene expression was determined by measuring mRNA levels. OCA dose-dependently increased fibroblast growth factor-19 (FGF-19) and small heterodimer partner (SHP) which, in turn, suppress mRNA levels of cholesterol 7-alpha-hydroxylase (CYP7A1), the rate-limiting enzyme for de novo synthesis of bile acids. Consistent with CYP7A1 suppression, total bile acid content was decreased by OCA (1 μmol/L) to 42.7 ± 20.5% relative to control. In addition to suppressing de novo bile acids synthesis, OCA significantly increased the mRNA levels of transporters involved in bile acid homeostasis. The bile salt excretory pump (BSEP), a canalicular efflux transporter, increased by 6.4 ± 0.8-fold, and the basolateral efflux heterodimer transporters, organic solute transporter α (OSTα ) and OSTβ increased by 6.4 ± 0.2-fold and 42.9 ± 7.9-fold, respectively. The upregulation of BSEP and OSTα and OSTβ, by OCA reduced the intracellular concentrations of d8 -TCA, a model bile acid, to 39.6 ± 8.9% relative to control. These data demonstrate that OCA does suppress bile acid synthesis and reduce hepatocellular bile acid levels, supporting the use of OCA to treat bile acid-induced toxicity observed in cholestatic diseases. © 2017 Intercept Pharmaceuticals. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and

  9. New insights into the regulation of plant immunity by amino acid metabolic pathways.

    PubMed

    Zeier, Jürgen

    2013-12-01

    Besides defence pathways regulated by classical stress hormones, distinct amino acid metabolic pathways constitute integral parts of the plant immune system. Mutations in several genes involved in Asp-derived amino acid biosynthetic pathways can have profound impact on plant resistance to specific pathogen types. For instance, amino acid imbalances associated with homoserine or threonine accumulation elevate plant immunity to oomycete pathogens but not to pathogenic fungi or bacteria. The catabolism of Lys produces the immune signal pipecolic acid (Pip), a cyclic, non-protein amino acid. Pip amplifies plant defence responses and acts as a critical regulator of plant systemic acquired resistance, defence priming and local resistance to bacterial pathogens. Asp-derived pyridine nucleotides influence both pre- and post-invasion immunity, and the catabolism of branched chain amino acids appears to affect plant resistance to distinct pathogen classes by modulating crosstalk of salicylic acid- and jasmonic acid-regulated defence pathways. It also emerges that, besides polyamine oxidation and NADPH oxidase, Pro metabolism is involved in the oxidative burst and the hypersensitive response associated with avirulent pathogen recognition. Moreover, the acylation of amino acids can control plant resistance to pathogens and pests by the formation of protective plant metabolites or by the modulation of plant hormone activity.

  10. Regulating fatty acids in infant formula: critical assessment of U.S. policies and practices

    PubMed Central

    2014-01-01

    Background Fatty acids in breast-milk such as docosahexaenoic acid and arachidonic acid, commonly known as DHA and ARA, contribute to the healthy development of children in various ways. However, the manufactured versions that are added to infant formula might not have the same health benefits as those in breast-milk. There is evidence that the manufactured additives might cause harm to infants’ health, and they might lead to unwarranted increases in the cost of infant formula. The addition of such fatty acids to infant formula needs to be regulated. In the U.S., the Food and Drug Administration has primary responsibility for regulating the composition of infant formula. The central purpose of this study is to assess the FDA’s efforts with regard to the regulation of fatty acids in infant formula. Methods This study is based on critical analysis of policies and practices described in publicly available documents of the FDA, the manufacturers of fatty acids, and other relevant organizations. The broad framework for this work was set out by the author in his book on Regulating Infant Formula, published in 2011. Results The FDA does not assess the safety or the health impacts of fatty acid additives to infant formula before they are marketed, and there is no systematic assessment after marketing is underway. Rather than making its own independent assessments, the FDA accepts the manufacturers’ claims regarding their products’ safety and effectiveness. Conclusions The FDA is not adequately regulating the use of fatty acid additives to infant formula. This results in exposure of infants to potential risks. Adverse reactions are already on record. Also, the additives have led to increasing costs of infant formula despite the lack of proven benefits to normal, full term infants. There is a need for more effective regulation of DHA and ARA additives to infant formula. PMID:24433303

  11. Regulation of branched-chain amino acid catabolism: nutritional and hormonal regulation of activity and expression of the branched-chain alpha-keto acid dehydrogenase kinase.

    PubMed

    Shimomura, Y; Obayashi, M; Murakami, T; Harris, R A

    2001-09-01

    Branched-chain alpha-keto acid dehydrogenase kinase is responsible for the inactivation and phosphorylation of the branched-chain alpha-keto acid dehydrogenase complex, the enzyme that catalyses the committed step of branched-chain amino acid catabolism. The activity of the branched-chain alpha-keto acid dehydrogenase complex is inversely correlated with kinase activity, suggesting that the relative activity of the kinase is the primary regulator of the activity of the complex. It has been shown that kinase activity and expression are affected by nutritional states imposed by low-protein diet feeding, starvation, diabetes, and exercise. Evidence has also been presented that certain hormones, particularly insulin, glucocorticoid, thyroid hormone and female sex hormones, affect the activity and expression of the kinase. The findings indicate that nutritional and hormonal control of the activity and expression of branched-chain alpha-keto acid dehydrogenase kinase provides an important means of control of the activity of the branched-chain alpha-keto acid dehydrogenase complex, with inactivation serving to conserve branched-chain amino acids for protein synthesis in some situations and activation serving to provide carbon for gluconeogenesis in others.

  12. New mechanisms that regulate Saccharomyces cerevisiae short peptide transporter achieve balanced intracellular amino acid concentrations.

    PubMed

    Melnykov, Artem V

    2016-01-01

    The budding yeast Saccharomyces cerevisiae is able to take up large quantities of amino acids in the form of di- and tripeptides via a short peptide transporter, Ptr2p. It is known that PTR2 can be induced by certain peptides and amino acids, and the mechanisms governing this upregulation are understood at the molecular level. We describe two new opposing mechanisms of regulation that emphasize potential toxicity of amino acids: the first is upregulation of PTR2 in a population of cells, caused by amino acid secretion that accompanies peptide uptake; the second is loss of Ptr2p activity, due to transporter internalization following peptide uptake. Our findings emphasize the importance of proper amino acid balance in the cell and extend understanding of peptide import regulation in yeast.

  13. The Campylobacter jejuni Ferric Uptake Regulator Promotes Acid Survival and Cross-Protection against Oxidative Stress

    PubMed Central

    Askoura, Momen; Sarvan, Sabina; Couture, Jean-François

    2016-01-01

    Campylobacter jejuni is a prevalent cause of bacterial gastroenteritis in humans worldwide. The mechanisms by which C. jejuni survives stomach acidity remain undefined. In the present study, we demonstrated that the C. jejuni ferric uptake regulator (Fur) plays an important role in C. jejuni acid survival and acid-induced cross-protection against oxidative stress. A C. jejuni Δfur mutant was more sensitive to acid than the wild-type strain. Profiling of the acid stimulon of the C. jejuni Δfur mutant allowed us to uncover Fur-regulated genes under acidic conditions. In particular, Fur was found to upregulate genes involved in flagellar and cell envelope biogenesis upon acid stress, and mutants with deletions of these genes were found to be defective in surviving acid stress. Interestingly, prior acid exposure of C. jejuni cross-protected against oxidative stress in a catalase (KatA)- and Fur-dependent manner. Western blotting and reverse transcription-quantitative PCR revealed increased expression of KatA upon acid stress. Electrophoretic mobility shift assays (EMSAs) demonstrated that the binding affinity between Fur and the katA promoter is reduced in vitro under conditions of low pH, rationalizing the higher levels of expression of katA under acidic conditions. Strikingly, the Δfur mutant exhibited reduced virulence in both human epithelial cells and the Galleria mellonella infection model. Altogether, this is the first study showing that, in addition to its role in iron metabolism, Fur is an important regulator of C. jejuni acid responses and this function cross-protects against oxidative stress. Moreover, our results clearly demonstrate Fur's important role in C. jejuni pathogenesis. PMID:26883589

  14. Microglial Acid Sensing Regulates Carbon Dioxide Evoked Fear

    PubMed Central

    Vollmer, Lauren Larke; Ghosal, Sriparna; McGuire, Jennifer L.; Ahlbrand, Rebecca L.; Li, Ke-Yong; Santin, Joseph M.; Ratliff-Rang, Christine A.; Patrone, Luis G. A.; Rush, Jennifer; Lewkowich, Ian P.; Herman, James P; Putnam, Robert W.; Sah, Renu

    2016-01-01

    Background Carbon dioxide (CO2) inhalation, a biological challenge and pathological marker in Panic Disorder, evokes intense fear and panic attacks in susceptible individuals. The molecular identity and anatomical location of CO2-sensing systems that translate CO2-evoked fear remains unclear. We investigated contributions of microglial acid sensor T cell death associated gene-8 (TDAG8) and microglial pro-inflammatory responses in CO2-evoked behavioral and physiological responses. Methods CO2-evoked freezing, autonomic and respiratory responses were assessed in TDAG8-deficient (−/−) and wildtype (+/+) mice. Involvement of TDAG8-dependent microglial activation and pro-inflammatory cytokine IL-1β with CO2-evoked responses was investigated using microglial blocker, minocycline and IL-1β antagonist, IL- 1RA. CO2-chemosensitive firing responses using single-cell patch clamping were measured in TDAG8−/− and +/+ mice to gain functional insights. Results; TDAG8 expression was localized in microglia enriched within the sensory circumventricular organs (CVOs). TDAG8−/− mice displayed attenuated CO2-evoked freezing and sympathetic responses. TDAG8 deficiency was associated with reduced microglial activation and pro-inflammatory cytokine, IL-1β within the subfornical organ (SFO). Central infusion of microglial activation blocker, minocycline and IL-1β antagonist, IL-1RA attenuated CO2-evoked freezing. Finally, CO2-evoked neuronal firing in patch clamped SFO neurons was dependent on acid sensor TDAG8 and IL-1β. Conclusions Our data identify TDAG8-dependent microglial acid-sensing as a unique chemosensor for detecting and translating hypercapnia to fear-associated behavioral and physiological responses, providing a novel mechanism for homeostatic threat detection of relevance to psychiatric conditions such as panic disorder. PMID:27422366

  15. Microglial Acid Sensing Regulates Carbon Dioxide-Evoked Fear.

    PubMed

    Vollmer, Lauren Larke; Ghosal, Sriparna; McGuire, Jennifer L; Ahlbrand, Rebecca L; Li, Ke-Yong; Santin, Joseph M; Ratliff-Rang, Christine A; Patrone, Luis G A; Rush, Jennifer; Lewkowich, Ian P; Herman, James P; Putnam, Robert W; Sah, Renu

    2016-10-01

    Carbon dioxide (CO2) inhalation, a biological challenge and pathologic marker in panic disorder, evokes intense fear and panic attacks in susceptible individuals. The molecular identity and anatomic location of CO2-sensing systems that translate CO2-evoked fear remain unclear. We investigated contributions of microglial acid sensor T cell death-associated gene-8 (TDAG8) and microglial proinflammatory responses in CO2-evoked behavioral and physiological responses. CO2-evoked freezing, autonomic, and respiratory responses were assessed in TDAG8-deficient ((-/-)) and wild-type ((+/+)) mice. Involvement of TDAG8-dependent microglial activation and proinflammatory cytokine interleukin (IL)-1β with CO2-evoked responses was investigated using microglial blocker, minocycline, and IL-1β antagonist IL-1RA. CO2-chemosensitive firing responses using single-cell patch clamping were measured in TDAG8(-/-) and TDAG8(+/+) mice to gain functional insights. TDAG8 expression was localized in microglia enriched within the sensory circumventricular organs. TDAG8(-/-) mice displayed attenuated CO2-evoked freezing and sympathetic responses. TDAG8 deficiency was associated with reduced microglial activation and proinflammatory cytokine IL-1β within the subfornical organ. Central infusion of microglial activation blocker minocycline and IL-1β antagonist IL-1RA attenuated CO2-evoked freezing. Finally, CO2-evoked neuronal firing in patch-clamped subfornical organ neurons was dependent on acid sensor TDAG8 and IL-1β. Our data identify TDAG8-dependent microglial acid sensing as a unique chemosensor for detecting and translating hypercapnia to fear-associated behavioral and physiological responses, providing a novel mechanism for homeostatic threat detection of relevance to psychiatric conditions such as panic disorder. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  16. Three-Dimensional Mapping of Ozone-Induced Injury in the Nasal Airways of Monkeys Using Magnetic Resonance Imaging and Morphometric Techniques

    SciTech Connect

    Carey, Stephen A.; Minard, Kevin R.; Trease, Lynn L.; Wagner, James G.; Garcia, Guilherme M.; Ballinger, Carol A.; Kimbell, Julia; Plopper, Charles G.; Corley, Rick A.; Postlewait, Ed; Harkema, Jack R.

    2007-03-01

    ABSTRACT Age-related changes in gross and microscopic structure of the nasal cavity can alter local tissue susceptibility as well as the dose of inhaled toxicant delivered to susceptible sites. This article describes a novel method for the use of magnetic resonance imaging, 3-dimensional airway modeling, and morphometric techniques to characterize the distribution and magnitude of ozone-induced nasal injury in infant monkeys. Using this method, we are able to generate age-specific, 3-dimensional, epithelial maps of the nasal airways of infant Rhesus macaques. The principal nasal lesions observed in this primate model of ozone-induced nasal toxicology were neutrophilic rhinitis, along with necrosis and exfoliation of the epithelium lining the anterior maxilloturbinate. These lesions, induced by acute or cyclic (episodic) exposures, were examined by light microscopy, quantified by morphometric techniques, and mapped on 3-dimensional models of the nasal airways. Here, we describe the histopathologic, imaging, and computational biology methods developed to efficiently characterize, localize, quantify, and map these nasal lesions. By combining these techniques, the location and severity of the nasal epithelial injury were correlated with epithelial type, nasal airway geometry, and local biochemical and molecular changes on an individual animal basis. These correlations are critical for accurate predictive modeling of exposure-dose-response relationships in the nasal airways, and subsequent extrapolation of nasal findings in animals to humans for developing risk assessment.

  17. Signalling of abscisic acid to regulate plant growth.

    PubMed Central

    Himmelbach, A; Iten, M; Grill, E

    1998-01-01

    Abscisic acid (ABA) mediated growth control is a fundamental response of plants to adverse environmental cues. The linkage between ABA perception and growth control is currently being unravelled by using different experimental approaches such as mutant analysis and microinjection experiments. So far, two protein phosphatases, ABI1 and ABI2, cADPR, pH, and Ca2+ have been identified as main components of the ABA signalling pathway. Here, the ABA signal transduction pathway is compared to signalling cascades from yeast and mammalian cells. A model for a bifurcated ABA signal transduction pathway exerting a positive and negative control mechanism is proposed. PMID:9800207

  18. Regulation of indole-3-acetic acid biosynthesis by branched-chain amino acids in Enterobacter cloacae UW5.

    PubMed

    Parsons, Cassandra V; Harris, Danielle M M; Patten, Cheryl L

    2015-09-01

    The soil bacterium Enterobacter cloacae UW5 produces the rhizosphere signaling molecule indole-3-acetic acid (IAA) via the indolepyruvate pathway. Expression of indolepyruvate decarboxylase, a key pathway enzyme encoded by ipdC, is upregulated by the transcription factor TyrR in response to aromatic amino acids. Some members of the TyrR regulon may also be controlled by branched-chain amino acids and here we show that expression from the ipdC promoter and production of IAA are downregulated by valine, leucine and isoleucine. Regulation of the IAA synthesis pathway by both aromatic and branched-chain amino acids suggests a broader role for this pathway in bacterial physiology, beyond plant interactions. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Abscisic acid coordinates nod factor and cytokinin signaling during the regulation of nodulation in Medicago truncatula.

    PubMed

    Ding, Yiliang; Kalo, Peter; Yendrek, Craig; Sun, Jongho; Liang, Yan; Marsh, John F; Harris, Jeanne M; Oldroyd, Giles E D

    2008-10-01

    Nodulation is tightly regulated in legumes to ensure appropriate levels of nitrogen fixation without excessive depletion of carbon reserves. This balance is maintained by intimately linking nodulation and its regulation with plant hormones. It has previously been shown that ethylene and jasmonic acid (JA) are able to regulate nodulation and Nod factor signal transduction. Here, we characterize the nature of abscisic acid (ABA) regulation of nodulation. We show that application of ABA inhibits nodulation, bacterial infection, and nodulin gene expression in Medicago truncatula. ABA acts in a similar manner as JA and ethylene, regulating Nod factor signaling and affecting the nature of Nod factor-induced calcium spiking. However, this action is independent of the ethylene signal transduction pathway. We show that genetic inhibition of ABA signaling through the use of a dominant-negative allele of ABSCISIC ACID INSENSITIVE1 leads to a hypernodulation phenotype. In addition, we characterize a novel locus of M. truncatula, SENSITIVITY TO ABA, that dictates the sensitivity of the plant to ABA and, as such, impacts the regulation of nodulation. We show that ABA can suppress Nod factor signal transduction in the epidermis and can regulate cytokinin induction of the nodule primordium in the root cortex. Therefore, ABA is capable of coordinately regulating the diverse developmental pathways associated with nodule formation and can intimately dictate the nature of the plants' response to the symbiotic bacteria.

  20. The discovery of the fat-regulating phosphatidic acid phosphatase gene

    PubMed Central

    CARMAN, George M.

    2011-01-01

    Phosphatidic acid phosphatase is a fat-regulating enzyme that plays a major role in controlling the balance of phosphatidic acid (substrate) and diacylglycerol (product), which are lipid precursors used for the synthesis of membrane phospholipids and triacylglycerol. Phosphatidic acid is also a signaling molecule that triggers phospholipid synthesis gene expression, membrane expansion, secretion, and endocytosis. While this important enzyme has been known for several decades, its gene was only identified recently from yeast. This discovery showed the importance of phosphatidic acid phosphatase in lipid metabolism in yeast as well as in higher eukaryotes including humans. PMID:21785579

  1. The discovery of the fat-regulating phosphatidic acid phosphatase gene.

    PubMed

    Carman, George M

    2011-05-01

    Phosphatidic acid phosphatase is a fat-regulating enzyme that plays a major role in controlling the balance of phosphatidic acid (substrate) and diacylglycerol (product), which are lipid precursors used for the synthesis of membrane phospholipids and triacylglycerol. Phosphatidic acid is also a signaling molecule that triggers phospholipid synthesis gene expression, membrane expansion, secretion, and endocytosis. While this important enzyme has been known for several decades, its gene was only identified recently from yeast. This discovery showed the importance of phosphatidic acid phosphatase in lipid metabolism in yeast as well as in higher eukaryotes including humans.

  2. 5-Aminolevulinic acid regulates the inflammatory response and alloimmune reaction.

    PubMed

    Fujino, Masayuki; Nishio, Yoshiaki; Ito, Hidenori; Tanaka, Tohru; Li, Xiao-Kang

    2016-08-01

    5-Aminolevulinic acid (5-ALA) is a naturally occurring amino acid and precursor of heme and protoporphyrin IX (PpIX). Exogenously administrated 5-ALA increases the accumulation of PpIX in tumor cells specifically due to the compromised metabolism of 5-ALA to heme in mitochondria. PpIX emits red fluorescence by the irradiation of blue light and the formation of reactive oxygen species and singlet oxygen. Thus, performing a photodynamic diagnosis (PDD) and photodynamic therapy (PDT) using 5-ALA have given rise to a new strategy for tumor diagnosis and therapy. In addition to the field of tumor therapy, 5-ALA has been implicated in the treatment of inflammatory disease, autoimmune disease and transplantation due to the anti-inflammation and immunoregulation properties that are elicited with the expression of heme oxygenase (HO)-1, an inducible enzyme that catalyzes the rate-limiting step in the oxidative degradation of heme to free iron, biliverdin and carbon monoxide (CO), in combination with sodium ferrous citrate (SFC), because an inhibitor of HO-1 abolishes the effects of 5-ALA. Furthermore, NF-E2-related factor 2 (Nrf2), mitogen-activated protein kinase (MAPK), and heme are involved in the HO-1 expression. Biliverdin and CO are also known to have anti-apoptotic, anti-inflammatory and immunoregulatory functions. We herein review the current use of 5-ALA in inflammatory diseases, transplantation medicine, and tumor therapy. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Peatlands and green frogs: A relationship regulated by acidity?

    USGS Publications Warehouse

    Mazerolle, M.J.

    2005-01-01

    The effects of site acidification on amphibian populations have been thoroughly addressed in the last decades. However, amphibians in naturally acidic environments, such as peatlands facing pressure from the peat mining industry, have received little attention. Through two field studies and an experiment, I assessed the use of bog habitats by the green frog (Rana clamitans melanota), a species sensitive to various forestry and peat mining disturbances. First, I compared the occurrence and breeding patterns of frogs in bog and upland ponds. I then evaluated frog movements between forest and bog habitats to determine whether they corresponded to breeding or postbreeding movements. Finally, I investigated, through a field experiment, the value of bogs as rehydrating areas for amphibians by offering living Sphagnum moss and two media associated with uplands (i.e., water with pH ca 6.5 and water-saturated soil) to acutely dehydrated frogs. Green frog reproduction at bog ponds was a rare event, and no net movements occurred between forest and bog habitats. However, acutely dehydrated frogs did not avoid Sphagnum. Results show that although green frogs rarely breed in bogs and do not move en masse between forest and bog habitats, they do not avoid bog substrates for rehydrating, despite their acidity. Thus, bogs offer viable summering habitat to amphibians, which highlights the value of these threatened environments in terrestrial amphibian ecology.

  4. Amino acid regulation of mammalian gene expression in the intestine.

    PubMed

    Brasse-Lagnel, Carole G; Lavoinne, Alain M; Husson, Annie S

    2010-07-01

    Some amino acids exert a wide range of regulatory effects on gene expression via the activation of different signalling pathways and transcription factors, and a number of cis elements were shown to respond to changes in amino acid concentration. Particular attention has been paid to the effects of glutamine and arginine, which modulate a number of cell functions through the activation of various pathways in different tissues. In the intestine, appropriate concentrations of both arginine and/or glutamine contribute to facilitate cell proliferation, to limit the inflammatory response and apoptosis, and to modulate intermediary metabolism through specific transcription factors. Particularly, besides its role as a major fuel for enterocytes, the regulatory effects of glutamine have been extensively studied and the molecular mechanisms involved appear diversified and complex. Indeed, in addition to a major role of NF-kappaB in its anti-inflammatory action and a stimulatory role of AP-1 in its growth-promoting action and cell survival, the involvement of some other transcription factors, such as PPAR-gamma or HSF-1, was shown to maintain intestinal cell integrity. The signalling pathways leading to the activation of transcription factors imply several kinases, particularly MAP kinases in the effect of glutamine and p70 S6 kinase for those of arginine, but in most cases the precise pathways from the entrance of the aminoacid into the cell to the activation of gene transcription has remained elusive.

  5. Regulation of hematogenous tumor metastasis by acid sphingomyelinase

    PubMed Central

    Carpinteiro, Alexander; Becker, Katrin Anne; Japtok, Lukasz; Hessler, Gabriele; Keitsch, Simone; Požgajovà, Miroslava; Schmid, Kurt W; Adams, Constantin; Müller, Stefan; Kleuser, Burkhard; Edwards, Michael J; Grassmé, Heike; Helfrich, Iris; Gulbins, Erich

    2015-01-01

    Metastatic dissemination of cancer cells is the ultimate hallmark of malignancy and accounts for approximately 90% of human cancer deaths. We investigated the role of acid sphingomyelinase (Asm) in the hematogenous metastasis of melanoma cells. Intravenous injection of B16F10 melanoma cells into wild-type mice resulted in multiple lung metastases, while Asm-deficient mice (Smpd1−/− mice) were protected from pulmonary tumor spread. Transplanting wild-type platelets into Asm-deficient mice reinstated tumor metastasis. Likewise, Asm-deficient mice were protected from hematogenous MT/ret melanoma metastasis to the spleen in a mouse model of spontaneous tumor metastasis. Human and mouse melanoma cells triggered activation and release of platelet secretory Asm, in turn leading to ceramide formation, clustering, and activation of α5β1 integrins on melanoma cells finally leading to adhesion of the tumor cells. Clustering of integrins by applying purified Asm or C16 ceramide to B16F10 melanoma cells before intravenous injection restored trapping of tumor cells in the lung in Asm-deficient mice. This effect was revertable by arginine-glycine-aspartic acid peptides, which are known inhibitors of integrins, and by antibodies neutralizing β1 integrins. These findings indicate that melanoma cells employ platelet-derived Asm for adhesion and metastasis. PMID:25851537

  6. Cadmium Induces Retinoic Acid Signaling by Regulating Retinoic Acid Metabolic Gene Expression*

    PubMed Central

    Cui, Yuxia; Freedman, Jonathan H.

    2009-01-01

    The transition metal cadmium is an environmental teratogen. In addition, cadmium and retinoic acid can act synergistically to induce forelimb malformations. The molecular mechanism underlying the teratogenicity of cadmium and the synergistic effect with retinoic acid has not been addressed. An evolutionarily conserved gene, β,β-carotene 15,15′-monooxygenase (BCMO), which is involved in retinoic acid biosynthesis, was studied in both Caenorhabditis elegans and murine Hepa 1–6 cells. In C. elegans, bcmo-1 was expressed in the intestine and was cadmium inducible. Similarly, in Hepa 1–6 cells, Bcmo1 was induced by cadmium. Retinoic acid-mediated signaling increased after 24-h exposures to 5 and 10 μm cadmium in Hepa 1–6 cells. Examination of gene expression demonstrated that the induction of retinoic acid signaling by cadmium may be mediated by overexpression of Bcmo1. Furthermore, cadmium inhibited the expression of Cyp26a1 and Cyp26b1, which are involved in retinoic acid degradation. These results indicate that cadmium-induced teratogenicity may be due to the ability of the metal to increase the levels of retinoic acid by disrupting the expression of retinoic acid-metabolizing genes. PMID:19556237

  7. RNA-binding protein ZFP36L1 maintains posttranscriptional regulation of bile acid metabolism.

    PubMed

    Tarling, Elizabeth J; Clifford, Bethan L; Cheng, Joan; Morand, Pauline; Cheng, Angela; Lester, Ellen; Sallam, Tamer; Turner, Martin; de Aguiar Vallim, Thomas Q

    2017-10-02

    Bile acids function not only as detergents that facilitate lipid absorption but also as signaling molecules that activate the nuclear receptor farnesoid X receptor (FXR). FXR agonists are currently being evaluated as therapeutic agents for a number of hepatic diseases due to their lipid-lowering and antiinflammatory properties. FXR is also essential for maintaining bile acid homeostasis and prevents the accumulation of bile acids. Elevated bile acids activate FXR, which in turn switches off bile acid synthesis by reducing the mRNA levels of bile acid synthesis genes, including cholesterol 7α-hydroxylase (Cyp7a1). Here, we show that FXR activation triggers a rapid posttranscriptional mechanism to degrade Cyp7a1 mRNA. We identified the RNA-binding protein Zfp36l1 as an FXR target gene and determined that gain and loss of function of ZFP36L1 reciprocally regulate Cyp7a1 mRNA and bile acid levels in vivo. Moreover, we found that mice lacking hepatic ZFP36L1 were protected from diet-induced obesity and steatosis. The reduced adiposity and antisteatotic effects observed in ZFP36L1-deficient mice were accompanied by impaired lipid absorption that was consistent with altered bile acid metabolism. Thus, the ZFP36L1-dependent regulation of bile acid metabolism is an important metabolic contributor to obesity and hepatosteatosis.

  8. Ellagic acid checks lymphoma promotion via regulation of PKC signaling pathway.

    PubMed

    Mishra, Sudha; Vinayak, Manjula

    2013-02-01

    Protein Kinase C (PKC) isozymes are key components involved in cell proliferation and their over activation leads to abnormal tumor growth. PKC follows signalling pathway by activation of downstream gene NF-kB and early transcription factor c-Myc. Over activation of NF-kB and c-Myc gene are also linked with unregulated proliferation of cancer cells. Therefore any agent which can inhibit the activation of Protein kinase C, NF-kB and c-Myc may be useful in reducing cancer progression. To investigate this hypothesis we have tested the effect of ellagic acid on these genes in Dalton's lymphoma bearing (DL). The role of ellagic acid was also tested in regulation of tumor suppressor gene Transforming growth factor-β1 (TGF-β1). DL mice were treated with three different doses (40, 60 and 80 mg/kg body weight) of ellagic acid. Ascites cells of mice were used for the experiments. Ellagic acid administration to DL mice decreased oxidative stress by reducing lipid peroxidation. Ellagic acid also down regulates the expression of classical isozymes of PKC i.e. PKCα, PKCβ, and PKCγ as well as activity of total PKC and NF-kB, indicating its antitumor action. The anticarcinogenic action of ellagic acid was also confirmed by up regulation of TGF-β1 and down regulation of c-Myc. Lymphoma prevention by ellagic acid is further supported by decrease in cell proliferation, cell viability, ascites fluid accumulation and increase in life span of DL mice. All these findings suggest that ellagic acid prevents the cancer progression by down regulation of PKC signaling pathway leading to cell proliferation.

  9. [The influence of simulated acid rain on acidity and K+ leaching regulation of different soil layers].

    PubMed

    Wang, Daizhang; Jiang, Xin; Bian, Yongrong; Sun, Lei; Li, Rui; He, Jizheng

    2003-03-01

    The influence of simulated acid rain on acidity and K+ release of different soil layers of red soil from Jiangxi was investigated in the lab when surface soil was mixed with KCl. The results indicated that pH of leaching solution first decreased, then increased in the different soil layers, but pH at the beginning moment of leaching existed prominent differences and pH of leachate of pH 2.5 acid rain in A and AB layers again decreased during subsequent stage. There was a peak value of EC of leachate appearing at the beginning stage, it showed that nutrient ions in soil rapidly moved downwards into lower depth of profile. K+ concentration of effluent solution was related to acidity of acid rain and the pH2.5 value of acid rain accelerated K+ transportation downwards along profile. K+ release of A soil layer was divided into two moments which one was the rapid rate of K+ release process at the moment of beginning and then into the middle rate of release process. As to pH 4.5 value of acid rain, it also existed rapid and slow rate processes.

  10. Glutamine metabolism regulates autophagy-dependent mTORC1 reactivation during amino acid starvation.

    PubMed

    Tan, Hayden Weng Siong; Sim, Arthur Yi Loong; Long, Yun Chau

    2017-08-24

    Activation of autophagy and elevation of glutamine synthesis represent key adaptations to maintain amino acid balance during starvation. In this study, we investigate the role of autophagy and glutamine on the regulation of mTORC1, a critical kinase that regulates cell growth and proliferation. We report that supplementation of glutamine alone is sufficient to restore mTORC1 activity during prolonged amino acid starvation. Inhibition of autophagy abolishes the restorative effect of glutamine, suggesting that reactivation of mTORC1 is autophagy-dependent. Inhibition of glutaminolysis or transamination impairs glutamine-mediated mTORC1 reactivation, suggesting glutamine reactivates mTORC1 specifically through its conversion to glutamate and restoration of non-essential amino acid pool. Despite a persistent drop in essential amino acid pool during amino acid starvation, crosstalk between glutamine and autophagy is sufficient to restore insulin sensitivity of mTORC1. Thus, glutamine metabolism and autophagy constitute a specific metabolic program which restores mTORC1 activity during amino acid starvation.mTORC1 is a critical kinase that regulates cell growth and proliferation. Here the authors show that glutamine metabolism is sufficient to restore mTORC1 activity during prolonged amino acid starvation in an autophagy-dependent manner.

  11. Local indigenous fruit derived juices as alternate source of acidity regulators.

    PubMed

    D'souza, Cassandra; Fernandes, Rosaline; Kudale, Subhash; Naik, Azza Silotry

    2017-09-20

    Acidity regulators are additives that alter and control food acidity. The objective of this study was to explore local indigenous fruits as source of natural acidity regulators. Juices extracted from Garcinia indica (kokum), Embilica officinalis (amla) and Tamarindus indica (tamarind) were used as acidulants for medium such as coconut milk and bottle gourd juice. The buffering capacity (β), acid composition, antioxidant activity and shelf-life study of the acidified media were estimated. Potentiometric titration showed G. indica to possess highest buffering capacity in both ranges. HPLC analysis showed T. indica contained high level of tartaric acid (4.84 ± 0.01 mg g(-1) ) while G. indica had citric acid (22.37 ± 0.84 mg g(-1) ) and E. officinalis had citric acid (2.75 ± 0.02 mg g(-1) ) along with ascorbic acid (2.68 ± 0.01 mg g(-1) ). DPPH scavenging activity was high for E. officinalis (91.24 ± 0.66 %) and T. indica (90.93 ± 0.817 %) and relatively lower for G. indica (34.61 ± 3.66 %). Shelf life study showed total plate count to be within the prescribed limits upto a week in accordance to safety regulations. The present investigation confirmed the suitability of indigenous fruit juices as alternatives to existing acidity regulators. This article is protected by copyright. All rights reserved.

  12. Betaine affects muscle lipid metabolism via regulating the fatty acid uptake and oxidation in finishing pig.

    PubMed

    Li, Sisi; Wang, Haichao; Wang, Xinxia; Wang, Yizhen; Feng, Jie

    2017-01-01

    Betaine affects fat metabolism in animals, but the specific mechanism is still not clear. The purpose of this study was to investigate possible mechanisms of betaine in altering lipid metabolism in muscle tissue in finishing pigs. A total of 120 crossbred gilts (Landrace × Yorkshire × Duroc) with an average initial body weight of 70.1 kg were randomly allotted to three dietary treatments. The treatments included a corn-soybean meal basal diet supplemented with 0, 1250 or 2500 mg/kg betaine. The feeding experiment lasted 42 d. Betaine addition to the diet significantly increased the concentration of free fatty acids (FFA) in muscle (P < 0.05). Furthermore, the levels of serum cholesterol and high-density lipoprotein cholesterol were decreased (P < 0.05) and total cholesterol content was increased in muscle (P < 0.05) of betaine fed pigs. Experiments on genes involved in fatty acid transport showed that betaine increased expression of lipoprotein lipase(LPL), fatty acid translocase/cluster of differentiation (FAT/CD36), fatty acid binding protein (FABP3) and fatty acid transport protein (FATP1) (P < 0.05). The abundance of fatty acid transport protein and fatty acid binding protein were also increased by betaine (P < 0.05). As for the key factors involved in fatty acid oxidation, although betaine supplementation didn't affect the level of carnitine and malonyl-CoA, betaine increased mRNA and protein abundance of carnitine palmitransferase-1(CPT1) and phosphorylated-AMPK (P < 0.05). The results suggested that betaine may promoted muscle fatty acid uptake via up-regulating the genes related to fatty acid transporter including FAT/CD36, FATP1 and FABP3. On the other hand, betaine activated AMPK and up-regulated genes related to fatty acid oxidation including PPARα and CPT1. The underlying mechanism regulating fatty acid metabolism in pigs supplemented with betaine is associated with the up-regulation of genes involved in fatty acid transport and fatty

  13. Oxalic acid alleviates chilling injury in peach fruit by regulating energy metabolism and fatty acid contents.

    PubMed

    Jin, Peng; Zhu, Hong; Wang, Lei; Shan, Timin; Zheng, Yonghua

    2014-10-15

    The effects of postharvest oxalic acid (OA) treatment on chilling injury, energy metabolism and membrane fatty acid content in 'Baifeng' peach fruit stored at 0°C were investigated. Internal browning was significantly reduced by OA treatment in peaches. OA treatment markedly inhibited the increase of ion leakage and the accumulation of malondialdehyde. Meanwhile, OA significantly increased the contents of adenosine triphosphate and energy charge in peach fruit. Enzyme activities of energy metabolism including H(+)-adenosine triphosphatase, Ca(2+)-adenosine triphosphatase, succinic dehydrogenase and cytochrome C oxidase were markedly enhanced by OA treatment. The ratio of unsaturated/saturated fatty acid in OA-treated fruit was significantly higher than that in control fruit. These results suggest that the alleviation in chilling injury by OA may be due to enhanced enzyme activities related to energy metabolism and higher levels of energy status and unsaturated/saturated fatty acid ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Essential amino acids: master regulators of nutrition and environmental footprint?

    PubMed Central

    Tessari, Paolo; Lante, Anna; Mosca, Giuliano

    2016-01-01

    The environmental footprint of animal food production is considered several-fold greater than that of crops cultivation. Therefore, the choice between animal and vegetarian diets may have a relevant environmental impact. In such comparisons however, an often neglected issue is the nutritional value of foods. Previous estimates of nutrients’ environmental footprint had predominantly been based on either food raw weight or caloric content, not in respect to human requirements. Essential amino acids (EAAs) are key parameters in food quality assessment. We re-evaluated here the environmental footprint (expressed both as land use for production and as Green House Gas Emission (GHGE), of some animal and vegetal foods, titrated to provide EAAs amounts in respect to human requirements. Production of high-quality animal proteins, in amounts sufficient to match the Recommended Daily Allowances of all the EAAs, would require a land use and a GHGE approximately equal, greater o smaller (by only ±1-fold), than that necessary to produce vegetal proteins, except for soybeans, that exhibited the smallest footprint. This new analysis downsizes the common concept of a large advantage, in respect to environmental footprint, of crops vs. animal foods production, when human requirements of EAAs are used for reference. PMID:27221394

  15. The global regulator LaeA controls production of citric acid and endoglucanases in Aspergillus carbonarius.

    PubMed

    Linde, Tore; Zoglowek, Marta; Lübeck, Mette; Frisvad, Jens Christian; Lübeck, Peter Stephensen

    2016-08-01

    The global regulatory protein LaeA is known for regulating the production of many kinds of secondary metabolites in Aspergillus species, as well as sexual and asexual reproduction, and morphology. In Aspergillus carbonarius, it has been shown that LaeA regulates production of ochratoxin. We have investigated the regulatory effect of LaeA on production of citric acid and cellulolytic enzymes in A. carbonarius. Two types of A. carbonarius strains, having laeA knocked out or overexpressed, were constructed and tested in fermentation. The knockout of laeA significantly decreased the production of citric acid and endoglucanases, but did not reduce the production of beta-glucosidases or xylanases. The citric acid accumulation was reduced with 74-96 % compared to the wild type. The endoglucanase activity was reduced with 51-78 %. Overexpression of LaeA seemed not to have an effect on citric acid production or on cellulose or xylanase activity.

  16. Expression and adaptive regulation of amino acid transport system A in a placental cell line under amino acid restriction.

    PubMed

    Jones, H N; Ashworth, C J; Page, K R; McArdle, H J

    2006-05-01

    Trans-placental transport of amino acids is vital for the developing fetus. Using the BeWo cell line as a placental model, we investigated the effect of restricting amino acid availability on amino acid transport system type A. BeWo cells were cultured either in amino acid-depleted (without non-essential amino acids) or control media for 1, 3, 5 or 6 h. System A function was analysed using alpha(methyl-amino)isobutyric acid (MeAIB) transcellular transport studies. Transporter (sodium coupled neutral amino acid transporter (SNAT1/2)) expression was analysed at mRNA and protein level by Northern and Western blotting respectively. Localisation was carried out using immunocytochemistry. MeAIB transcellular transport was significantly (P < 0.05) increased by incubation of the cells in amino acid-depleted medium for 1 h, and longer incubation times caused further increases in the rate of transfer. However, the initial response was not accompanied by an increase in SNAT2 mRNA; this occurred only after 3 h and further increased for the rest of the 6-h incubation. Similarly, it took several hours for a significant increase in SNAT2 protein expression. In contrast, relocalisation of existing SNAT2 transporters occurred within 30 min of amino acid restriction and continued throughout the 6-h incubation. When the cells were incubated in medium with even lower amino acid levels (without non-essential plus 0.5 x essential amino acids), SNAT2 mRNA levels showed further significant (P < 0.0001) up-regulation. However, incubation of cells in depleted medium for 6 h caused a significant (P = 0.014) decrease in the expression of SNAT1 mRNA. System L type amino acid transporter 2 (LAT2) expression was not changed by amino acid restriction, indicating that the responses seen in the system A transporters were not a general cell response. These data have shown that placental cells adapt in vitro to nutritional stress and have identified the physiological, biochemical and genomic

  17. Regulation of protein synthesis by amino acids in muscle of neonates

    PubMed Central

    Suryawan, Agus; Davis, Teresa A.

    2011-01-01

    The marked increase in skeletal muscle mass during the neonatal period is largely due to a high rate of postprandial protein synthesis that is modulated by an enhanced sensitivity to insulin and amino acids. The amino acid signaling pathway leading to the stimulation of protein synthesis has not been fully elucidated. Among the amino acids, leucine is considered to be a principal anabolic agent that regulates protein synthesis. mTORC1, which controls protein synthesis, has been implicated as a target for leucine. Until recently, there have been few studies exploring the role of amino acids in enhancing muscle protein synthesis in vivo. In this review, we discuss amino acid-induced protein synthesis in muscle in the neonate, focusing on current knowledge of the role of amino acids in the activation of mTORC1 leading to mRNA translation. The role of the amino acid transporters, SNAT2, LAT1, and PAT, in the modulation of mTORC1 activation and the role of amino acids in the activation of putative regulators of mTORC1, i.e., raptor, Rheb, MAP4K3, Vps34, and Rag GTPases, are discussed. PMID:21196241

  18. Zoledronic acid and geranylgeraniol regulate cellular behaviour and angiogenic gene expression in human gingival fibroblasts.

    PubMed

    Zafar, S; Coates, D E; Cullinan, M P; Drummond, B K; Milne, T; Seymour, G J

    2014-10-01

    The mevalonate pathway (MVP) and the anti-angiogenic effect of bisphosphonates have been shown to play a role in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study determined the effect of the bisphosphonate, zoledronic acid and the replenishment of the MVP by geranylgeraniol on human gingival fibroblasts. Cell viability, apoptosis, morphological analysis using transmission electron microscopy, and gene expression for vascular endothelial growth factor A, bone morphogenic protein 2, ras homologue gene family member B, epiregulin and interferon-alpha were conducted. Results showed cellular viability was decreased in the presence of zoledronic acid and the co-addition of zoledronic acid with geranylgeraniol restored cell viability to control levels. Caspase 3/7 was detected in zoledronic-acid-treated cells indicating apoptosis. Transmission electron microscopy revealed dilation of the rough endoplasmic reticulum with zoledronic acid and the appearance of multiple lipid-like vesicles following the addition of geranylgeraniol. Zoledronic acid significantly (P < 0.05, FR > ± 2) up-regulated vascular endothelial growth factor A, bone morphogenic protein 2, ras homologue gene family member B and epiregulin at one or more time points but not interferon-alpha. Addition of geranylgeraniol resulted in a reduction in the expression of all five genes compared with zoledronic-acid-treated human gingival fibroblasts. The study concluded geranylgeraniol partially reversed the effects of zoledronic acid in human gingival fibroblasts both at the cellular and genetic levels, suggesting the regulation of these genes is mediated via the mevalonate pathway.

  19. Regulation of podocyte survival and endoplasmic reticulum stress by fatty acids.

    PubMed

    Sieber, Jonas; Lindenmeyer, Maja Tamara; Kampe, Kapil; Campbell, Kirk Nicholas; Cohen, Clemens David; Hopfer, Helmut; Mundel, Peter; Jehle, Andreas Werner

    2010-10-01

    Apoptosis of podocytes is considered critical in the pathogenesis of diabetic nephropathy (DN). Free fatty acids (FFAs) are critically involved in the pathogenesis of diabetes mellitus type 2, in particular the regulation of pancreatic β cell survival. The objectives of this study were to elucidate the role of palmitic acid, palmitoleic, and oleic acid in the regulation of podocyte cell death and endoplasmic reticulum (ER) stress. We show that palmitic acid increases podocyte cell death, both apoptosis and necrosis of podocytes, in a dose and time-dependent fashion. Palmitic acid induces podocyte ER stress, leading to an unfolded protein response as reflected by the induction of the ER chaperone immunoglobulin heavy chain binding protein (BiP) and proapoptotic C/EBP homologous protein (CHOP) transcription factor. Of note, the monounsaturated palmitoleic and oleic acid can attenuate the palmitic acid-induced upregulation of CHOP, thereby preventing cell death. Similarly, gene silencing of CHOP protects against palmitic acid-induced podocyte apoptosis. Our results offer a rationale for interventional studies aimed at testing whether dietary shifting of the FFA balance toward unsaturated FFAs can delay the progression of DN.

  20. Regulation of podocyte survival and endoplasmic reticulum stress by fatty acids

    PubMed Central

    Sieber, Jonas; Lindenmeyer, Maja Tamara; Kampe, Kapil; Campbell, Kirk Nicholas; Cohen, Clemens David; Hopfer, Helmut; Mundel, Peter

    2010-01-01

    Apoptosis of podocytes is considered critical in the pathogenesis of diabetic nephropathy (DN). Free fatty acids (FFAs) are critically involved in the pathogenesis of diabetes mellitus type 2, in particular the regulation of pancreatic β cell survival. The objectives of this study were to elucidate the role of palmitic acid, palmitoleic, and oleic acid in the regulation of podocyte cell death and endoplasmic reticulum (ER) stress. We show that palmitic acid increases podocyte cell death, both apoptosis and necrosis of podocytes, in a dose and time-dependent fashion. Palmitic acid induces podocyte ER stress, leading to an unfolded protein response as reflected by the induction of the ER chaperone immunoglobulin heavy chain binding protein (BiP) and proapoptotic C/EBP homologous protein (CHOP) transcription factor. Of note, the monounsaturated palmitoleic and oleic acid can attenuate the palmitic acid-induced upregulation of CHOP, thereby preventing cell death. Similarly, gene silencing of CHOP protects against palmitic acid-induced podocyte apoptosis. Our results offer a rationale for interventional studies aimed at testing whether dietary shifting of the FFA balance toward unsaturated FFAs can delay the progression of DN. PMID:20668104

  1. Amino acid limitation induces down-regulation of WNT5a at transcriptional level

    SciTech Connect

    Wang Zuguang; Chen Hong

    2009-01-23

    An aberrant WNT signaling contributes to the development and progression of multiple cancers. WNT5a is one of the WNT signaling molecules. This study was designed to test the hypothesis that amino acid deprivation induces changes in the WNT signaling pathway in colon cancer cells. Results showed that targets of the amino acid response pathway, ATF3 and p21, were induced in the human colon cancer cell line SW480 during amino acid limitation. There was a significant decrease in the WNT5a mRNA level following amino acid deprivation. The down-regulation of WNT5a mRNA by amino acid deprivation is not due to mRNA destabilization. There is a reduction of nuclear {beta}-catenin protein level by amino acid limitation. Under amino acid limitation, phosphorylation of ERK1/2 was increased and the blockage of ERK1/2 by the inhibitor U0126 partially restored WNT5a mRNA level. In conclusion, amino acid limitation in colon cancer cells induces phosphorylation of ERK1/2, which then down-regulates WNT5a expression.

  2. Regulation of fatty acid metabolism by cell autonomous circadian clocks: time to fatten up on information?

    PubMed

    Bray, Molly S; Young, Martin E

    2011-04-08

    Molecular, cellular, and animal-based studies have recently exposed circadian clocks as critical regulators of energy balance. Invariably, mouse models of genetically manipulated circadian clock components display features indicative of altered lipid/fatty acid metabolism, including differential adiposity and circulating lipids. The purpose of this minireview is to provide a comprehensive summary of current knowledge regarding the regulation of fatty acid metabolism by distinct cell autonomous circadian clocks. The implications of these recent findings for cardiometabolic disease and human health are discussed.

  3. Exercise and Amino Acid Anabolic Cell Signaling and the Regulation of Skeletal Muscle Mass

    PubMed Central

    Pasiakos, Stefan M.

    2012-01-01

    A series of complex intracellular networks influence the regulation of skeletal muscle protein turnover. In recent years, studies have examined how cellular regulators of muscle protein turnover modulate metabolic mechanisms contributing to the loss, gain, or conservation of skeletal muscle mass. Exercise and amino acids both stimulate anabolic signaling potentially through several intracellular pathways including the mammalian target of rapamycin complex 1 and the mitogen activated protein kinase cell signaling cascades. As novel molecular regulators of muscle integrity continue to be explored, a contemporary analysis of the literature is required to understand the metabolic mechanisms by which contractile forces and amino acids affect cellular process that contribute to long-term adaptations and preservation of muscle mass. This article reviews the literature related to how exercise and amino acid availability affect cellular regulators of skeletal muscle mass, especially highlighting recent investigations that have identified mechanisms by which contractile forces and amino acids modulate muscle health. Furthermore, this review will explore integrated exercise and nutrition strategies that promote the maintenance of muscle health by optimizing exercise, and amino acid-induced cell signaling in aging adults susceptible to muscle loss. PMID:22852061

  4. Exercise and amino acid anabolic cell signaling and the regulation of skeletal muscle mass.

    PubMed

    Pasiakos, Stefan M

    2012-07-01

    A series of complex intracellular networks influence the regulation of skeletal muscle protein turnover. In recent years, studies have examined how cellular regulators of muscle protein turnover modulate metabolic mechanisms contributing to the loss, gain, or conservation of skeletal muscle mass. Exercise and amino acids both stimulate anabolic signaling potentially through several intracellular pathways including the mammalian target of rapamycin complex 1 and the mitogen activated protein kinase cell signaling cascades. As novel molecular regulators of muscle integrity continue to be explored, a contemporary analysis of the literature is required to understand the metabolic mechanisms by which contractile forces and amino acids affect cellular process that contribute to long-term adaptations and preservation of muscle mass. This article reviews the literature related to how exercise and amino acid availability affect cellular regulators of skeletal muscle mass, especially highlighting recent investigations that have identified mechanisms by which contractile forces and amino acids modulate muscle health. Furthermore, this review will explore integrated exercise and nutrition strategies that promote the maintenance of muscle health by optimizing exercise, and amino acid-induced cell signaling in aging adults susceptible to muscle loss.

  5. Regulation of silicosis formation by lysophosphatidic acid and its receptors.

    PubMed

    Cong, Cuicui; Mao, Lijun; Zhang, Yanlin; Zhao, Zanmei; Xu, Xixian; Zhao, Jinyuan

    2014-09-01

    Silicosis is a serious occupational disease characterized by lung fibrosis that is caused by long-term inhalation of silica-containing fine particles. Lysophosphatidic acid (LPA) and LPA1/3 plays a role in lung fibrosis. Until recently, there has been little research investigating the role of LPA and LPA receptors (LPAR) in silica-induced development of pulmonary fibrosis. In this study, we evaluated the hypothesis that LPA and LPA1/3 may play a role in silicosis pathogenesis using rat silicosis models induced by intratracheal instillation of silica, and randomly divided into control, silica, and VPC-12249 groups. LPA serum and bronchoalveolar lavage fluid (BALF) levels were quantified by ELISA. α-smooth muscle actin (α-SMA), type I and III collagen protein expression was quantified by western blotting (WB), and type I and III collagen mRNAs detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Lung hydroxyproline (HYP) levels were detected using alkaline hydrolysis, with hematoxylin and eosin (H&E) and picrosirius red staining used for pathological examination. In vitro experiments showed that LPA stimulated fibroblasts proliferated in a time and dose-dependent manner and promoted expression of α-SMA, and type I and III collagen. Moreover, LPA serum and BALF levels increased in silica-instilled rats. In vivo and in vitro experiments revealed that α-SMA expression and collagen deposition reduced significantly after VPC-12249 treatment, and histopathological results show VPC-12249 alleviates silicosis progression. In conclusion, our findings suggest that LPA promotes the proliferation, transformation, and collagen synthesis of fibroblasts, and that LPA-LPA1/3 are involved in the development of silicosis and may serve as novel therapeutic targets for treatment.

  6. Regulation of L-ascorbic acid content in strawberry fruits

    PubMed Central

    Cruz-Rus, Eduardo; Amaya, Iraida; Sánchez-Sevilla, José F.; Botella, Miguel A.; Valpuesta, Victoriano

    2011-01-01

    Plants have several L-ascorbic acid (AsA) biosynthetic pathways, but the contribution of each one to the synthesis of AsA varyies between different species, organs, and developmental stages. Strawberry (Fragaria×ananassa) fruits are rich in AsA. The pathway that uses D-galacturonate as the initial substrate is functional in ripe fruits, but the contribution of other pathways to AsA biosynthesis has not been studied. The transcription of genes encoding biosynthetic enzymes such as D-galacturonate reductase (FaGalUR) and myo-inositol oxygenase (FaMIOX), and the AsA recycling enzyme monodehydroascorbate reductase (FaMDHAR) were positively correlated with the increase in AsA during fruit ripening. Fruit storage for 72 h in a cold room reduced the AsA content by 30%. Under an ozone atmosphere, this reduction was 15%. Ozone treatment increased the expression of the FaGalUR, FaMIOX, and L-galactose-1-phosphate phosphatase (FaGIPP) genes, and transcription of the L-galactono-1,4-lactone dehydrogenase (FaGLDH) and FAMDHAR genes was higher in the ozone-stored than in the air-stored fruits. Analysis of AsA content in a segregating population from two strawberry cultivars showed high variability, which did not correlate with the transcription of any of the genes studied. Study of GalUR protein in diverse cultivars of strawberry and different Fragaria species showed that a correlation between GalUR and AsA content was apparent in most cases, but it was not general. Three alleles were identified in strawberry, but any sequence effect on the AsA variability was eliminated by analysis of the allele-specific expression. Taken together, these results indicate that FaGalUR shares the control of AsA levels with other enzymes and regulatory elements in strawberry fruit. PMID:21561953

  7. Abscisic Acid as Pathogen Effector and Immune Regulator

    PubMed Central

    Lievens, Laurens; Pollier, Jacob; Goossens, Alain; Beyaert, Rudi; Staal, Jens

    2017-01-01

    Abscisic acid (ABA) is a sesquiterpene signaling molecule produced in all kingdoms of life. To date, the best known functions of ABA are derived from its role as a major phytohormone in plant abiotic stress resistance. Different organisms have developed different biosynthesis and signal transduction pathways related to ABA. Despite this, there are also intriguing common themes where ABA often suppresses host immune responses and is utilized by pathogens as an effector molecule. ABA also seems to play an important role in compatible mutualistic interactions such as mycorrhiza and rhizosphere bacteria with plants, and possibly also the animal gut microbiome. The frequent use of ABA in inter-species communication could be a possible reason for the wide distribution and re-invention of ABA as a signaling molecule in different organisms. In humans and animal models, it has been shown that ABA treatment or nutrient-derived ABA is beneficial in inflammatory diseases like colitis and type 2 diabetes, which confer potential to ABA as an interesting nutraceutical or pharmacognostic drug. The anti-inflammatory activity, cellular metabolic reprogramming, and other beneficial physiological and psychological effects of ABA treatment in humans and animal models has sparked an interest in this molecule and its signaling pathway as a novel pharmacological target. In contrast to plants, however, very little is known about the ABA biosynthesis and signaling in other organisms. Genes, tools and knowledge about ABA from plant sciences and studies of phytopathogenic fungi might benefit biomedical studies on the physiological role of endogenously generated ABA in humans. PMID:28469630

  8. Glycyrrhizin, silymarin, and ursodeoxycholic acid regulate a common hepatoprotective pathway in HepG2 cells.

    PubMed

    Hsiang, Chien-Yun; Lin, Li-Jen; Kao, Shung-Te; Lo, Hsin-Yi; Chou, Shun-Ting; Ho, Tin-Yun

    2015-07-15

    Glycyrrhizin, silymarin, and ursodeoxycholic acid are widely used hepatoprotectants for the treatment of liver disorders, such as hepatitis C virus infection, primary biliary cirrhosis, and hepatocellular carcinoma. The gene expression profiles of HepG2 cells responsive to glycyrrhizin, silymarin, and ursodeoxycholic acid were analyzed in this study. HepG2 cells were treated with 25 µM hepatoprotectants for 24 h. Gene expression profiles of hepatoprotectants-treated cells were analyzed by oligonucleotide microarray in triplicates. Nuclear factor-κB (NF-κB) activities were assessed by luciferase assay. Among a total of 30,968 genes, 252 genes were commonly regulated by glycyrrhizin, silymarin, and ursodeoxycholic acid. These compounds affected the expression of genes relevant various biological pathways, such as neurotransmission, and glucose and lipid metabolism. Genes involved in hepatocarcinogenesis, apoptosis, and anti-oxidative pathways were differentially regulated by all compounds. Moreover, interaction networks showed that NF-κB might play a central role in the regulation of gene expression. Further analysis revealed that these hepatoprotectants inhibited NF-κB activities in a dose-dependent manner. Our data suggested that glycyrrhizin, silymarin, and ursodeoxycholic acid regulated the expression of genes relevant to apoptosis and oxidative stress in HepG2 cells. Moreover, the regulation by these hepatoprotectants might be relevant to the suppression of NF-κB activities. Copyright © 2015 Elsevier GmbH. All rights reserved.

  9. Organic Acids Regulation of Chemical-Microbial Phosphorus Transformations in Soils.

    PubMed

    Menezes-Blackburn, Daniel; Paredes, Cecilia; Zhang, Hao; Giles, Courtney D; Darch, Tegan; Stutter, Marc; George, Timothy S; Shand, Charles; Lumsdon, David; Cooper, Patricia; Wendler, Renate; Brown, Lawrie; Blackwell, Martin; Wearing, Catherine; Haygarth, Philip M

    2016-11-01

    We have used an integrated approach to study the mobility of inorganic phosphorus (P) from soil solid phase as well as the microbial biomass P and respiration at increasing doses of citric and oxalic acid in two different soils with contrasting agronomic P status. Citric or oxalic acids significantly increased soil solution P concentrations for doses over 2 mmol kg(-1). However, low organic acid doses (<2 mmol kg(-1)) were associated with a steep increase in microbial biomass P, which was not seen for higher doses. In both soils, treatment with the tribasic citric acid led to a greater increase in soil solution P than the dibasic oxalic acid, likely due to the rapid degrading of oxalic acids in soils. After equilibration of soils with citric or oxalic acids, the adsorbed-to-solution distribution coefficient (Kd) and desorption rate constants (k-1) decreased whereas an increase in the response time of solution P equilibration (Tc) was observed. The extent of this effect was shown to be both soil and organic acid specific. Our results illustrate the critical thresholds of organic acid concentration necessary to mobilize sorbed and precipitated P, bringing new insight on how the exudation of organic acids regulate chemical-microbial soil phosphorus transformations.

  10. Milk fat globules: fatty acid composition, size and in vivo regulation of fat liquidity.

    PubMed

    Timmen, H; Patton, S

    1988-07-01

    Populations of large and small milk fat globules were isolated and analyzed to determine differences in fatty acid composition. Globule samples were obtained by centrifugation from milks of a herd and of individual animals produced under both pasture and barn feeding. Triacylglycerols of total globule lipids were prepared by thin layer chromatography and analyzed for fatty acid composition by gas chromatography. Using content of the acids in large globules as 100%, small globules contained fewer short-chain acids, -5.9%, less stearic acid, -22.7%, and more oleic acids, +4.6%, mean values for five trials. These differences are consistent with alternative use of short-chain acids or oleic acid converted from stearic acid to maintain liquidity at body temperature of milk fat globules and their precursors, intracellular lipid droplets. Stearyl-CoA desaturase (EC 1.14.99.5), which maintains fluidity of cellular endoplasmic reticulum membrane, is suggested to play a key role in regulating globule fat liquidity. Possible origins of differences between individual globules in fatty acid composition of their triacylglycerols are discussed.

  11. Uric acid regulates hepatic steatosis and insulin resistance through the NLRP3 inflammasome-dependent mechanism.

    PubMed

    Wan, Xingyong; Xu, Chengfu; Lin, Yiming; Lu, Chao; Li, Dejian; Sang, Jianzhong; He, Haijian; Liu, Xiao; Li, Youming; Yu, Chaohui

    2016-04-01

    Hyperuricemia significantly increases risk of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. However, the mechanisms responsible for this association are as yet unclear. This study aimed to investigate the effects and underlying mechanisms of uric acid on development of NAFLD and insulin resistance. We initially analyzed the impact of uric acid on the development of hepatic steatosis and insulin resistance in mice and in two cell models, HepG2 and L02. Subsequently, we studied the role of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in uric acid-induced fat accumulation and insulin signaling impairment. We found that uric acid directly induces hepatocyte fat accumulation, insulin resistance, and insulin signaling impairment both in vivo and in vitro. We also found that uric acid-induced NLRP3 inflammasome activation, whereas lowering uric acid by allopurinol inhibited NLRP3 inflammasome activation in a high fat diet mouse model of NAFLD. Moreover, knocking down NLRP3 expression significantly attenuated uric acid-induced fat accumulation both in HepG2 cells and L02 cells. Knocking down NLRP3 expression also rescued uric acid-induced insulin signaling impairment in both cell types. Uric acid regulates hepatic steatosis and insulin resistance through the NLRP3 inflammasome. Uric acid may be a new therapeutic target for NAFLD and insulin resistance. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  12. 1-Acetylpyrene-salicylic acid: photoresponsive fluorescent organic nanoparticles for the regulated release of a natural antimicrobial compound, salicylic acid.

    PubMed

    Barman, Shrabani; Mukhopadhyay, Sourav K; Behara, Krishna Kalyani; Dey, Satyahari; Singh, N D Pradeep

    2014-05-28

    Photoresponsive 1-acetylpyrene-salicylic acid (AcPy-SA) nanoparticles (NPs) were developed for the regulated release of a natural antimicrobial compound, salicylic acid. The strong fluorescent properties of AcPy-SA NPs have been extensively used for potential in vitro cell imaging. The phototrigger capability of our newly prepared AcPy-SA NPs was utilized for the efficient release of an antimicrobial compound, salicylic acid. The photoregulated drug release of AcPy-SA NPs has been shown by the subsequent switching off and on of a visible-light source. In vitro biological studies reveal that AcPy-SA NPs of ∼68 nm size deliver the antimicrobial drug salicylic acid into the bacteria cells (Pseudomonas aeruginosa) and efficiently kill the cells upon exposure to visible light (≥410 nm). Such photoresponsive fluorescent organic NPs will be highly beneficial for targeted and regulated antimicrobial drug release because of their biocompatible nature, efficient cellular uptake, and light-induced drug release ability.

  13. Co-expression analysis identifies CRC and AP1 the regulator of Arabidopsis fatty acid biosynthesis.

    PubMed

    Han, Xinxin; Yin, Linlin; Xue, Hongwei

    2012-07-01

    Fatty acids (FAs) play crucial rules in signal transduction and plant development, however, the regulation of FA metabolism is still poorly understood. To study the relevant regulatory network, fifty-eight FA biosynthesis genes including de novo synthases, desaturases and elongases were selected as "guide genes" to construct the co-expression network. Calculation of the correlation between all Arabidopsis thaliana (L.) genes with each guide gene by Arabidopsis co-expression dating mining tools (ACT) identifies 797 candidate FA-correlated genes. Gene ontology (GO) analysis of these co-expressed genes showed they are tightly correlated to photosynthesis and carbohydrate metabolism, and function in many processes. Interestingly, 63 transcription factors (TFs) were identified as candidate FA biosynthesis regulators and 8 TF families are enriched. Two TF genes, CRC and AP1, both correlating with 8 FA guide genes, were further characterized. Analyses of the ap1 and crc mutant showed the altered total FA composition of mature seeds. The contents of palmitoleic acid, stearic acid, arachidic acid and eicosadienoic acid are decreased, whereas that of oleic acid is increased in ap1 and crc seeds, which is consistent with the qRT-PCR analysis revealing the suppressed expression of the corresponding guide genes. In addition, yeast one-hybrid analysis and electrophoretic mobility shift assay (EMSA) revealed that CRC can bind to the promoter regions of KCS7 and KCS15, indicating that CRC may directly regulate FA biosynthesis. © 2012 Institute of Botany, Chinese Academy of Sciences.

  14. Fatty acid esters produced by Lasiodiplodia theobromae function as growth regulators in tobacco seedlings

    SciTech Connect

    Uranga, Carla C.; Beld, Joris; Mrse, Anthony; Córdova-Guerrero, Iván; Burkart, Michael D.; Hernández-Martínez, Rufina

    2016-04-01

    The Botryosphaeriaceae are a family of trunk disease fungi that cause dieback and death of various plant hosts. This work sought to characterize fatty acid derivatives in a highly virulent member of this family, Lasiodiplodia theobromae. Nuclear magnetic resonance and gas chromatography-mass spectrometry of an isolated compound revealed (Z, Z)-9,12-ethyl octadecadienoate, (trivial name ethyl linoleate), as one of the most abundant fatty acid esters produced by L. theobromae. A variety of naturally produced esters of fatty acids were identified in Botryosphaeriaceae. In comparison, the production of fatty acid esters in the soil-borne tomato pathogen Fusarium oxysporum, and the non-phytopathogenic fungus Trichoderma asperellum was found to be limited. Ethyl linoleate, ethyl hexadecanoate (trivial name ethyl palmitate), and ethyl octadecanoate, (trivial name ethyl stearate), significantly inhibited tobacco seed germination and altered seedling leaf growth patterns and morphology at the highest concentration (0.2 mg/mL) tested, while ethyl linoleate and ethyl stearate significantly enhanced growth at low concentrations, with both still inducing growth at 98 ng/mL. This work provides new insights into the role of naturally esterified fatty acids from L. theobromae as plant growth regulators with similar activity to the well-known plant growth regulator gibberellic acid. - Highlights: • Lasiodiplodia theobromae produces a wide variety of fatty acid esters in natural substrates. • Ethyl stearate and ethyl linoleate inhibit tobacco germination at 0.2 mg/mL. • Ethyl stearate and ethyl linoleate induce tobacco germination at 98 ng/mL. • Tobacco growth increase in ethyl stearate and ethyl linoleate parallels gibberellic acid. • A role as plant growth regulators is proposed for fatty acid esters.

  15. Yeast genes involved in response to lactic acid and acetic acid: acidic conditions caused by the organic acids in Saccharomyces cerevisiae cultures induce expression of intracellular metal metabolism genes regulated by Aft1p.

    PubMed

    Kawahata, Miho; Masaki, Kazuo; Fujii, Tsutomu; Iefuji, Haruyuki

    2006-09-01

    Using two types of genome-wide analysis to investigate yeast genes involved in response to lactic acid and acetic acid, we found that the acidic condition affects metal metabolism. The first type is an expression analysis using DNA microarrays to investigate 'acid shock response' as the first step to adapt to an acidic condition, and 'acid adaptation' by maintaining integrity in the acidic condition. The other is a functional screening using the nonessential genes deletion collection of Saccharomyces cerevisiae. The expression analysis showed that genes involved in stress response, such as YGP1, TPS1 and HSP150, were induced under the acid shock response. Genes such as FIT2, ARN1 and ARN2, involved in metal metabolism regulated by Aft1p, were induced under the acid adaptation. AFT1 was induced under acid shock response and under acid adaptation with lactic acid. Moreover, green fluorescent protein-fused Aft1p was localized to the nucleus in cells grown in media containing lactic acid, acetic acid, or hydrochloric acid. Both analyses suggested that the acidic condition affects cell wall architecture. The depletion of cell-wall components encoded by SED1, DSE2, CTS1, EGT2, SCW11, SUN4 and YNL300W and histone acetyltransferase complex proteins encoded by YID21, EAF3, EAF5, EAF6 and YAF9 increased resistance to lactic acid. Depletion of the cell-wall mannoprotein Sed1p provided resistance to lactic acid, although the expression of SED1 was induced by exposure to lactic acid. Depletion of vacuolar membrane H+-ATPase and high-osmolarity glycerol mitogen-activated protein kinase proteins caused acid sensitivity. Moreover, our quantitative PCR showed that expression of PDR12 increased under acid shock response with lactic acid and decreased under acid adaptation with hydrochloric acid.

  16. PhoPQ regulates acidic glycerophospholipid content of the Salmonella Typhimurium outer membrane.

    PubMed

    Dalebroux, Zachary D; Matamouros, Susana; Whittington, Dale; Bishop, Russell E; Miller, Samuel I

    2014-02-04

    Gram-negative bacteria have two lipid membranes separated by a periplasmic space containing peptidoglycan. The surface bilayer, or outer membrane (OM), provides a barrier to toxic molecules, including host cationic antimicrobial peptides (CAMPs). The OM comprises an outer leaflet of lipid A, the bioactive component of lipopolysaccharide (LPS), and an inner leaflet of glycerophospholipids (GPLs). The structure of lipid A is environmentally regulated in a manner that can promote bacterial infection by increasing bacterial resistance to CAMP and reducing LPS recognition by the innate immune system. The gastrointestinal pathogen, Salmonella Typhimurium, responds to acidic pH and CAMP through the PhoPQ two-component regulatory system, which stimulates lipid A remodeling, CAMP resistance, and intracellular survival within acidified phagosomes. Work here demonstrates that, in addition to regulating lipid A structure, the S. Typhimurium PhoPQ virulence regulators also regulate acidic GPL by increasing the levels of cardiolipins and palmitoylated acylphosphatidylglycerols within the OM. Triacylated palmitoyl-PG species were diminished in strains deleted for the PhoPQ-regulated OM lipid A palmitoyltransferase enzyme, PagP. Purified PagP transferred palmitate to PG consistent with PagP acylation of both lipid A and PG within the OM. Therefore, PhoPQ coordinately regulates OM acidic GPL with lipid A structure, suggesting that GPLs cooperate with lipid A to form an OM barrier critical for CAMP resistance and intracellular survival of S. Typhimurium.

  17. Linoleic acid participates in the response to ischemic brain injury through oxidized metabolites that regulate neurotransmission.

    PubMed

    Hennebelle, Marie; Zhang, Zhichao; Metherel, Adam H; Kitson, Alex P; Otoki, Yurika; Richardson, Christine E; Yang, Jun; Lee, Kin Sing Stephen; Hammock, Bruce D; Zhang, Liang; Bazinet, Richard P; Taha, Ameer Y

    2017-06-28

    Linoleic acid (LA; 18:2 n-6), the most abundant polyunsaturated fatty acid in the US diet, is a precursor to oxidized metabolites that have unknown roles in the brain. Here, we show that oxidized LA-derived metabolites accumulate in several rat brain regions during CO2-induced ischemia and that LA-derived 13-hydroxyoctadecadienoic acid, but not LA, increase somatic paired-pulse facilitation in rat hippocampus by 80%, suggesting bioactivity. This study provides new evidence that LA participates in the response to ischemia-induced brain injury through oxidized metabolites that regulate neurotransmission. Targeting this pathway may be therapeutically relevant for ischemia-related conditions such as stroke.

  18. Core Amino Acid Residues in the Morphology-Regulating Protein, Mms6, for Intracellular Magnetite Biomineralization

    PubMed Central

    Yamagishi, Ayana; Narumiya, Kaori; Tanaka, Masayoshi; Matsunaga, Tadashi; Arakaki, Atsushi

    2016-01-01

    Living organisms produce finely tuned biomineral architectures with the aid of biomineral-associated proteins. The functional amino acid residues in these proteins have been previously identified using in vitro and in silico experimentation in different biomineralization systems. However, the investigation in living organisms is limited owing to the difficulty in establishing appropriate genetic techniques. Mms6 protein, isolated from the surface of magnetite crystals synthesized in magnetotactic bacteria, was shown to play a key role in the regulation of crystal morphology. In this study, we have demonstrated a defect in the specific region or substituted acidic amino acid residues in the Mms6 protein for observing their effect on magnetite biomineralization in vivo. Analysis of the gene deletion mutants and transformants of Magnetospirillum magneticum AMB-1 expressing partially truncated Mms6 protein revealed that deletions in the N-terminal or C-terminal regions disrupted proper protein localization to the magnetite surface, resulting in a change in the crystal morphology. Moreover, single amino acid substitutions at Asp123, Glu124, or Glu125 in the C-terminal region of Mms6 clearly indicated that these amino acid residues had a direct impact on magnetite crystal morphology. Thus, these consecutive acidic amino acid residues were found to be core residues regulating magnetite crystal morphology. PMID:27759096

  19. Distinct amino acid-sensing mTOR pathways regulate skeletal myogenesis.

    PubMed

    Yoon, Mee-Sup; Chen, Jie

    2013-12-01

    Signaling through the mammalian target of rapamycin (mTOR) in response to amino acid availability controls many cellular and developmental processes. mTOR is a master regulator of myogenic differentiation, but the pathways mediating amino acid signals in this process are not known. Here we examine the Rag GTPases and the class III phosphoinositide 3-kinase (PI3K) Vps34, two mediators of amino acid signals upstream of mTOR complex 1 (mTORC1) in cell growth regulation, for their potential involvement in myogenesis. We find that, although both Rag and Vps34 mediate amino acid activation of mTORC1 in C2C12 myoblasts, they have opposing functions in myogenic differentiation. Knockdown of RagA/B enhances, whereas overexpression of active RagB/C mutants impairs, differentiation, and this inhibitory function of Rag is mediated by mTORC1 suppression of the IRS1-PI3K-Akt pathway. On the other hand, Vps34 is required for myogenic differentiation. Amino acids activate a Vps34-phospholipase D1 (PLD1) pathway that controls the production of insulin-like growth factor II, an autocrine inducer of differentiation, through the Igf2 muscle enhancer. The product of PLD, phosphatidic acid, activates the enhancer in a rapamycin-sensitive but mTOR kinase-independent manner. Our results uncover amino acid-sensing mechanisms controlling the homeostasis of myogenesis and underline the versatility and context dependence of mTOR signaling.

  20. FABP4 reversed the regulation of leptin on mitochondrial fatty acid oxidation in mice adipocytes.

    PubMed

    Gan, Lu; Liu, Zhenjiang; Cao, Weina; Zhang, Zhenzhen; Sun, Chao

    2015-08-27

    Fatty acid binding protein 4 (FABP4), plays key role in fatty acid transportation and oxidation, and increases with leptin synergistically during adipose inflammation process. However, the regulation mechanism between FABP4 and leptin on mitochondrial fatty acid oxidation remains unclear. In this study, we found that FABP4 reduced the expression of leptin, CPT-1 and AOX1 in mice adipocytes. Conversely, FABP4 was down-regulated in a time-dependent manner by leptin treatment. Additionally, forced expression of FABP4 attenuated the expression of PGC1-α, UCP2, CPT-1, AOX1 and COX2 compared with leptin incubation. Moreover, mitochondrial membrane potential, fatty acid oxidation enzyme medium-chain acyl-CoA dehydrogenase (MCAD), long-chain acyl-CoA dehydrogenase (LCAD) and Cyt C levels were reduced in response to the overexpression of FABP4. These reductions correspond well with the reduced release of free fatty acid and the inactivation of mitochondrial complexes I and III by FABP4 overexpression. Furthermore, addition of the Akt/mTOR pathway-specific inhibitor (MK2206) blocked the mitochondrial fatty acid oxidation and respiration factors, whereas interference of FABP4 overcame these effects. Taken together, FABP4 could reverse the activation of the leptin-induced mitochondrial fatty acid oxidation, and the inhibition of Akt/mTOR signal pathway played a key role in this process.

  1. FABP4 reversed the regulation of leptin on mitochondrial fatty acid oxidation in mice adipocytes

    PubMed Central

    Gan, Lu; Liu, Zhenjiang; Cao, Weina; Zhang, Zhenzhen; Sun, Chao

    2015-01-01

    Fatty acid binding protein 4 (FABP4), plays key role in fatty acid transportation and oxidation, and increases with leptin synergistically during adipose inflammation process. However, the regulation mechanism between FABP4 and leptin on mitochondrial fatty acid oxidation remains unclear. In this study, we found that FABP4 reduced the expression of leptin, CPT-1 and AOX1 in mice adipocytes. Conversely, FABP4 was down-regulated in a time-dependent manner by leptin treatment. Additionally, forced expression of FABP4 attenuated the expression of PGC1-α, UCP2, CPT-1, AOX1 and COX2 compared with leptin incubation. Moreover, mitochondrial membrane potential, fatty acid oxidation enzyme medium-chain acyl-CoA dehydrogenase (MCAD), long-chain acyl-CoA dehydrogenase (LCAD) and Cyt C levels were reduced in response to the overexpression of FABP4. These reductions correspond well with the reduced release of free fatty acid and the inactivation of mitochondrial complexes I and III by FABP4 overexpression. Furthermore, addition of the Akt/mTOR pathway-specific inhibitor (MK2206) blocked the mitochondrial fatty acid oxidation and respiration factors, whereas interference of FABP4 overcame these effects. Taken together, FABP4 could reverse the activation of the leptin-induced mitochondrial fatty acid oxidation, and the inhibition of Akt/mTOR signal pathway played a key role in this process. PMID:26310911

  2. Core Amino Acid Residues in the Morphology-Regulating Protein, Mms6, for Intracellular Magnetite Biomineralization.

    PubMed

    Yamagishi, Ayana; Narumiya, Kaori; Tanaka, Masayoshi; Matsunaga, Tadashi; Arakaki, Atsushi

    2016-10-19

    Living organisms produce finely tuned biomineral architectures with the aid of biomineral-associated proteins. The functional amino acid residues in these proteins have been previously identified using in vitro and in silico experimentation in different biomineralization systems. However, the investigation in living organisms is limited owing to the difficulty in establishing appropriate genetic techniques. Mms6 protein, isolated from the surface of magnetite crystals synthesized in magnetotactic bacteria, was shown to play a key role in the regulation of crystal morphology. In this study, we have demonstrated a defect in the specific region or substituted acidic amino acid residues in the Mms6 protein for observing their effect on magnetite biomineralization in vivo. Analysis of the gene deletion mutants and transformants of Magnetospirillum magneticum AMB-1 expressing partially truncated Mms6 protein revealed that deletions in the N-terminal or C-terminal regions disrupted proper protein localization to the magnetite surface, resulting in a change in the crystal morphology. Moreover, single amino acid substitutions at Asp123, Glu124, or Glu125 in the C-terminal region of Mms6 clearly indicated that these amino acid residues had a direct impact on magnetite crystal morphology. Thus, these consecutive acidic amino acid residues were found to be core residues regulating magnetite crystal morphology.

  3. [Regulation effects of grafting on cinnamic acid and vanillin in eggplant root exudates].

    PubMed

    Chen, Shao-li; Zhou, Bao-li; Wang, Ru-hua; Fu, Ya-wen

    2008-11-01

    Cinnamic acid and vanillin are the allelochemicals commonly existed in eggplant root exudates. With pot culture experiment, the regulation effects of grafting on the cinnamic acid and vanillin in eggplant root exudates were studied, and the results showed that grafting decreased the amount of the two substances, especially of vanillin, in eggplants root system. The maximum reduction amount of cinnamic acid reached 68.96%, and that of vanillin reached 100%. Under the stress of exotic cinnamic acid and vanillin, especially of exotic cinnamic acid, grafting relieved the autotoxicity of the two substances on eggplants. Compared with own-rooted eggplant, grafted eggplant had a higher plant height and a larger stem diameter, its leaf chlorophyll content increased by 5.26%-13.12%, root electric conductivity and MDA content decreased, and root SOD activity enhanced.

  4. Renal regulation of acid-base equilibrium during chronic administration of mineral acid.

    PubMed Central

    De Sousa, R C; Harrington, J T; Ricanati, E S; Shelkrot, J W; Schwartz, W B

    1974-01-01

    Previous studies in metabolic alkalosis have demonstrated that two factors are the prime determinants of acid excretion and bicarbonate reabsorption; first, the diversion to distal exchange sites of sodium previously reabsorbed in the proximal tubule and loop of Henle; and, second, a stimulus to sodium-cation exchange greater than that produced by a low-salt diet alone. In the present study we have examined the hypothesis that these two factors are also the prime determinants of acid excretion during the administration of mineral acid loads. To test this hypothesis, we have administered to dogs ingesting a low NaCl diet a daily dose of 7 meq/kg of H+ with anions (chloride, sulfate, or nitrate) whose differing degrees of reabsorbability influence the speed and completeness with which each is delivered to the distal nephron with its accompanying Na+. After 2-3 wk of acid administration, and after an initial urinary loss of Na+ and K+, the steady-state value for plasma [HCO3-] was 8.6 meq/liter below control in the HCl group, 3.7 meq/liter below control in the H2SO4 group, and unchanged from control in the HNO3 group; all of these values were significantly different from each other. We would propose the following explanation for our findings: when HCl is administered chronically, marked acidosis occurs because distal delivery of Cl- is restricted by the ease with which the Cl- can be reabsorbed in the proximal portions of the nephron. Only when Cl- retention produces sufficient hyperchloremia to insure delivery of Na+ (previously reabsorbed in proximal tubule and loop of Henle) to the distal nephron in quantities equal to ingested Cl is this primary constraint removed. In the case of sulfuric and nitric acids, there is no constraint on distal delivery, the nonreabsorbability of the administered anion causing prompt, total delivery of Na+ to exchange sites in quantities equal to administered hydrogen. Thus, with H2SO4 and HNO3 the sole constraint on removal of the acid

  5. The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid.

    PubMed

    Luo, Shun-Tao; Zhang, Dong-Mei; Qin, Qing; Lu, Lian; Luo, Min; Guo, Fu-Chun; Shi, Hua-Shan; Jiang, Li; Shao, Bin; Li, Meng; Yang, Han-Shuo; Wei, Yu-Quan

    2017-02-06

    The simultaneous increases in blood lactic acid and erythrocytes after intense exercise could suggest a link between lactate and the erythropoiesis. However, the effects of lactic acid on erythropoiesis remain to be elucidated. Here, we utilized a mouse model to determine the role of lactic acid in this process in parallel with studies using leukaemic K562 cells. Treatment of K562 cells in vitro with lactic acid increased the mRNA and protein expression of haemoglobin genes and the frequency of GPA(+) cells. Also, increases in haematocrit and CD71(-)/Ter119(+) erythroid cells were observed in lactic acid-treated mice, which showed a physiological increase in blood lactate. Mouse bone marrow CD34(+)/CD117(-) cells showed an increase in erythroid burst-forming units after stimulation with lactic acid in vitro. Furthermore, lactic acid increased the intracellular reactive oxygen species (ROS) content in bone marrow and in K562 cells. Erythroid differentiation induced in Haematopoietic Stem Cells (HSCs) and K562 cells by lactic acid was abolished by reducing ROS levels with SOD or 2-mercaptoethanol, which suggests that ROS is a critical regulator of this process. These findings provide a better understanding of the role of lactic acid in cellular metabolism and physiological functions.

  6. The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid

    PubMed Central

    Luo, Shun-Tao; Zhang, Dong-Mei; Qin, Qing; Lu, Lian; Luo, Min; Guo, Fu-Chun; Shi, Hua-Shan; Jiang, Li; Shao, Bin; Li, Meng; Yang, Han-Shuo; Wei, Yu-Quan

    2017-01-01

    The simultaneous increases in blood lactic acid and erythrocytes after intense exercise could suggest a link between lactate and the erythropoiesis. However, the effects of lactic acid on erythropoiesis remain to be elucidated. Here, we utilized a mouse model to determine the role of lactic acid in this process in parallel with studies using leukaemic K562 cells. Treatment of K562 cells in vitro with lactic acid increased the mRNA and protein expression of haemoglobin genes and the frequency of GPA+ cells. Also, increases in haematocrit and CD71−/Ter119+ erythroid cells were observed in lactic acid-treated mice, which showed a physiological increase in blood lactate. Mouse bone marrow CD34+/CD117− cells showed an increase in erythroid burst-forming units after stimulation with lactic acid in vitro. Furthermore, lactic acid increased the intracellular reactive oxygen species (ROS) content in bone marrow and in K562 cells. Erythroid differentiation induced in Haematopoietic Stem Cells (HSCs) and K562 cells by lactic acid was abolished by reducing ROS levels with SOD or 2-mercaptoethanol, which suggests that ROS is a critical regulator of this process. These findings provide a better understanding of the role of lactic acid in cellular metabolism and physiological functions. PMID:28165036

  7. Phosphodiesterase isozymes involved in regulating acid secretion in the isolated mouse stomach.

    PubMed

    Okuda, S; Honda, M; Ito, Y; Aihara, E; Kato, S; Mitsufuji, S; Yoshikawa, T; Takeuchi, K

    2009-12-01

    The effect of subtype-selective phosphodiesterase (PDE) inhibitors on acid secretion was examined in mouse stomachs to investigate which PDE isozymes are involved in the local regulation of this secretion. Male DDY mice were used after 18 h fasting. An isolated stomach was incubated in an organ bath containing buffered solution gassed with 95% O(2)/5% CO(2), while the lumen was perfused with unbuffered solution gassed with 100% O(2). Acid secretion was measured at pH 5.4 using a pH-stat method. Histamine or pituitary adenylate cyclase activating polypeptide (PACAP) was added to the serosal solution. PDE inhibitors were added to the serosal solution 30 min before histamine or PACAP. The secretion of acid in the isolated stomach was increased by histamine or PACAP, and these responses were totally inhibited by famotidine. IBMX alone increased basal acid secretion and significantly enhanced the acid responses to histamine and PACAP. Among the PDE inhibitors tested, only rolipram (PDE4 inhibitor) significantly increased basal acid secretion and potentiated the acid responses to histamine and PACAP. The latter peptide increased histamine release into the medium, and this response was also enhanced by rolipram. Furthermore, rolipram significantly increased cAMP production induced in the isolated stomach by histamine and PACAP. These results suggest that PDE4 is involved in the local regulation of gastric acid secretion via the degradation of cAMP and that the PDE4 inhibitor rolipram increases the secretion of acid by potentiating acid production in parietal cells and enhancing histamine release from enterochromaffin-like cells.

  8. Responsiveness to acidity via metal ion regulators mediates virulence in the gastric pathogen Helicobacter pylori.

    PubMed

    Bury-Moné, Stéphanie; Thiberge, Jean-Michel; Contreras, Monica; Maitournam, Aboubakar; Labigne, Agnès; De Reuse, Hilde

    2004-07-01

    The virulence of pathogenic bacteria is dependent on their adaptation to and survival in the stressful conditions encountered in their hosts. Helicobacter pylori exclusively colonizes the acid stomach of primates, making it an ideal study model. Little is known about how H. pylori responds to the moderately acidic conditions encountered at its colonization site, the gastric mucus layer. Thus, we compared gene expression profiles of H. pylori 26695 grown at neutral and acidic pH, and validated the data for a selection of genes by real-time polymerase chain reaction, dot-blots or enzymatic assays. During growth in acidic conditions, 56 genes were upregulated and 45 genes downregulated. We found that acidity is a signal modulating the expression of several virulence factors. Regulation of genes related to metal ion homeostasis suggests protective mechanisms involving diminished transport and enhanced storage. Genes encoding subunits of the F0F1 ATPase and of a newly identified Na+/H+ antiporter (NhaC-HP0946) were downregulated, revealing that this bacterium uses original mechanisms to control proton entry. Five of the upregulated genes encoded proteins controlling intracellular ammonia synthesis, including urease, amidase and formamidase, underlining the major role of this buffering compound in the protection against acidity in H. pylori. Regulatory networks and transcriptome analysis as well as enzymatic assays implicated two metal-responsive transcriptional regulators (NikR and Fur) and an essential two-component response regulator (HP0166, OmpR-like) as effectors of the H. pylori acid response. Finally, a nikR-fur mutant is attenuated in the mouse model, emphasizing the link between response to acidity, metal metabolism and virulence in this gastric pathogen.

  9. Fatty acid unsaturation, mobilization, and regulation in the response of plants to stress

    USDA-ARS?s Scientific Manuscript database

    Stress acclimating plants respond to abiotic and biotic stress by remodeling membrane fluidity and the release of a-linolenic from membrane lipid. The adjustment of membrane lipid fluidity occurs through changes in unsaturated fatty acid levels, a function provided by the regulated activity of...

  10. The Regulation of Acid-Base Balance--A Microprocessor Simulation.

    ERIC Educational Resources Information Center

    Rasch, Robert W.

    1983-01-01

    Describes a computer program designed to simulate the regulation of acid-base balance, emphasizing regulatory compensations involved in the total process. Includes discussion of equations involved, a sample run of the program, and program listing (MicroSoft Basic). (JN)

  11. Synthesis and regulation of chlorogenic acid in potato: Rerouting phenylpropanoid flux in HQT silenced lines

    USDA-ARS?s Scientific Manuscript database

    Chlorogenic acid (CGA) is the major phenolic sink in potato tubers and can constitute over 90% of total phenylpropanoids. The regulation of CGA biosynthesis in potato and the role of the CGA biosynthetic gene hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase (HQT) was characterized. A sucros...

  12. The Regulation of Acid-Base Balance--A Microprocessor Simulation.

    ERIC Educational Resources Information Center

    Rasch, Robert W.

    1983-01-01

    Describes a computer program designed to simulate the regulation of acid-base balance, emphasizing regulatory compensations involved in the total process. Includes discussion of equations involved, a sample run of the program, and program listing (MicroSoft Basic). (JN)

  13. Acid rain compliance and coordination of state and federal utility regulation

    SciTech Connect

    Nordhaus, R.R.

    1993-07-01

    The Clean Air Act Amendments of 1990 (CAAA) impose new controls on emissions by electric utilities of the two major precursors of acid rain: sulfur dioxide and oxides of nitrogen. Utilities, and the utility holding company systems and power pools of which they are members, will be subject to extensive and costly compliance obligations under the new stature. Most of these utilities, utility systems, and power pools are regulated by more than one utility regulatory authority. Utility regulators will need to coordinate their policies for ratemaking and for review of acid rain compliance strategies if least-cost solutions are to be implemented without imposing on rate payers and utility shareholders the costs and risks of inconsistent regulatory determinations. This article outlines the scope of the coordination problem and spells out possible approaches that utility regulators may take in dealing with it. Topics covered include the following: the 1990 Clean Air Act Amendments; acid rain (SO2); acid rain (NOx); costs of compliance; implications for utility regulation - federal and state utility regulatory framework; potential jurisdictional conflicts under existing state/federal utility regulatory scheme - single utility, holding companies, power pools; Utility regulatory issues under the 1990 amendments - planning conflicts, operational conflicts; methods for dealing with potential jurisdictional conflicts; coordination mechanisms - informal consultation, rulemaking,coordination of adjudicatory proceedings, FERC rate filings.

  14. Eicosapentaenoic acid regulates brown adipose tissue gene expression and metabolism in high fat fed mice

    USDA-ARS?s Scientific Manuscript database

    Brown adipose tissue (BAT) is a thermogenic tissue, a key regulator of energy balance and a potential therapeutic target for obesity. We previously reported that eicosapentaenoic acid (EPA) reduced high fat (HF) diet-induced obesity and insulin resistance in mice, independent of energy intake. We hy...

  15. NR4A orphan nuclear receptors influence retinoic acid and docosahexaenoic acid signaling via up-regulation of fatty acid binding protein 5

    SciTech Connect

    Volakakis, Nikolaos; Joodmardi, Eliza; Perlmann, Thomas

    2009-12-25

    The orphan nuclear receptor (NR) Nurr1 is expressed in the developing and adult nervous system and is also induced as an immediate early gene in a variety of cell types. In silico analysis of human promoters identified fatty acid binding protein 5 (FABP5), a protein shown to enhance retinoic acid-mediated PPAR{beta}/{delta} signaling, as a potential Nurr1 target gene. Nurr1 has previously been implicated in retinoid signaling via its heterodimerization partner RXR. Since NRs are commonly involved in cross-regulatory control we decided to further investigate the regulatory relationship between Nurr1 and FABP5. FABP5 expression was up-regulated by Nurr1 and other NR4A NRs in HEK293 cells, and Nurr1 was shown to activate and bind to the FABP5 promoter, supporting that FABP5 is a direct downstream target of NR4A NRs. We also show that the RXR ligand docosahexaenoic acid (DHA) can induce nuclear translocation of FABP5. Moreover, via up-regulation of FABP5 Nurr1 can enhance retinoic acid-induced signaling of PPAR{beta}/{delta} and DHA-induced activation of RXR. We also found that other members of the NR4A orphan NRs can up-regulate FABP5. Thus, our findings suggest that NR4A orphan NRs can influence signaling events of other NRs via control of FABP5 expression levels.

  16. Effects of dietary strong acid anion challenge on regulation of acid-base balance in sheep.

    PubMed

    Las, J E; Odongo, N E; Lindinger, M I; AlZahal, O; Shoveller, A K; Matthews, J C; McBride, B W

    2007-09-01

    The acid-base status of the extracellular fluid is directly affected by the concentrations of strong basic cations and strong acid anions that are absorbed into the bloodstream from the diet. The objective of this study was to develop and characterize a model for dietary acid challenge in sheep by decreasing the dietary cation-anion difference (DCAD) using NutriChlor (HCl-treated canola meal), an anionic feed supplement. Ten fully fleeced sheep (Rideau-Arcott, 54.3 +/- 6.7 kg of BW) were fed either a control supplement [200 g/d of canola meal, DCAD = 184 mEq/kg of DM, calculated as (Na+ + K+) - (Cl- + S2-)] or an anionic supplement (AS; 200 g/d of NutriChlor, DCAD = -206 mEq/kg of DM) offered twice daily at 0700 and 1100 in a randomized complete block design. The sheep were individually housed and limit-fed a basal diet of dehydrated alfalfa pellets (22% CP and 1.2 Mcal of NE(g)/kg, DM basis) at 1.1 kg of DM/d offered twice daily at 1000 and 1300. Two days before the beginning of the experiment, the sheep were fitted with vinyl catheters (0.86-mm i.d., 1.32-mm o.d.) in the left jugular vein to facilitate blood sampling. Blood and urine samples were obtained daily from 1100 to 1130 on d 1 through 9 and at 0700, 1000, 1300, 1600, and 1900 on d 10. Blood was analyzed for hematocrit, plasma pH, gases, strong ions, and total protein. Urine samples were analyzed for pH. The AS induced a nonrespiratory acid-base disturbance associated with lower (P < 0.05) plasma pH (7.47 vs. 7.39), lower (P < 0.05) urine pH (8.13 vs. 6.09), and lower (P < 0.05) strong ion difference (42.5 vs. 39.5). The AS reduced (P < 0.05) the concentration of plasma glucose, base excess, and bicarbonate and increased (P < 0.05) the concentration of K+ and Cl-. Lowering DCAD increased (P < 0.05) Ca2+ concentrations in plasma by 13%. In conclusion, this dietary model successfully induced a significant acid-base disturbance in sheep. Although the acidifying effects of negative DCAD in the diet may have

  17. Recent advances in understanding trans-epithelial acid-base regulation and excretion mechanisms in cephalopods

    PubMed Central

    Hu, Marian Y; Hwang, Pung-Pung; Tseng, Yung-Che

    2015-01-01

    Cephalopods have evolved complex sensory systems and an active lifestyle to compete with fish for similar resources in the marine environment. Their highly active lifestyle and their extensive protein metabolism has led to substantial acid-base regulatory abilities enabling these organisms to cope with CO2 induced acid-base disturbances. In convergence to teleost, cephalopods possess an ontogeny-dependent shift in ion-regulatory epithelia with epidermal ionocytes being the major site of embryonic acid-base regulation and ammonia excretion, while gill epithelia take these functions in adults. Although the basic morphology and excretory function of gill epithelia in cephalopods were outlined almost half a century ago, modern immunohistological and molecular techniques are bringing new insights to the mechanistic basis of acid-base regulation and excretion of nitrogenous waste products (e.g. NH3/NH4+) across ion regulatory epithelia of cephalopods. Using cephalopods as an invertebrate model, recent findings reveal partly conserved mechanisms but also novel aspects of acid-base regulation and nitrogen excretion in these exclusively marine animals. Comparative studies using a range of marine invertebrates will create a novel and exciting research direction addressing the evolution of pH regulatory and excretory systems. PMID:26716070

  18. Large lead/acid batteries for frequency regulation, load levelling and solar power applications

    NASA Astrophysics Data System (ADS)

    Wagner, R.

    Lead/acid batteries are suitable for a multitude of utility applications. This paper presents some examples where large lead/acid batteries have been used for frequency regulation, load levelling and solar power applications. The operational experiences are given together with a discussion about the design and technical specialities of these batteries. In 1986, a 17 MW/14 MWh battery was installed at BEWAG in Berlin which, at that time, was the largest lead/acid battery in the world. Designed to strengthen Berlin's 'island' system, it was used since the beginning of 1987 for frequency regulation and spinning reserve. In December 1993, when Berlin was connected to the electricity grid, frequency regulation was no longer required but the battery was still used for spinning reserve. For many years, the industrial battery plant of Hagen in Soest has used a large lead/acid battery for load levelling. The experience gained during more than ten years shows that load levelling and peak shaving can be a marked benefit for customers and utilities with regard to reducing their peak demand. In the summer of 1992, a 216 V and 2200 Ah lead/acid battery with positive tubular plates and gelled electrolyte was installed at a solar power plant in Flanitzhutte, a small village in the south of Germany which is not connected to the electricity grid. A report is given of the first years of use and includes a discussion about the best charge strategy for such gel batteries when used for solar power applications.

  19. Recent advances in understanding trans-epithelial acid-base regulation and excretion mechanisms in cephalopods.

    PubMed

    Hu, Marian Y; Hwang, Pung-Pung; Tseng, Yung-Che

    2015-01-01

    Cephalopods have evolved complex sensory systems and an active lifestyle to compete with fish for similar resources in the marine environment. Their highly active lifestyle and their extensive protein metabolism has led to substantial acid-base regulatory abilities enabling these organisms to cope with CO2 induced acid-base disturbances. In convergence to teleost, cephalopods possess an ontogeny-dependent shift in ion-regulatory epithelia with epidermal ionocytes being the major site of embryonic acid-base regulation and ammonia excretion, while gill epithelia take these functions in adults. Although the basic morphology and excretory function of gill epithelia in cephalopods were outlined almost half a century ago, modern immunohistological and molecular techniques are bringing new insights to the mechanistic basis of acid-base regulation and excretion of nitrogenous waste products (e.g. NH3/NH4 (+)) across ion regulatory epithelia of cephalopods. Using cephalopods as an invertebrate model, recent findings reveal partly conserved mechanisms but also novel aspects of acid-base regulation and nitrogen excretion in these exclusively marine animals. Comparative studies using a range of marine invertebrates will create a novel and exciting research direction addressing the evolution of pH regulatory and excretory systems.

  20. Regulation of water-soluble phenolic acid biosynthesis in Salvia miltiorrhiza Bunge.

    PubMed

    Ma, Pengda; Liu, Jingling; Zhang, Chenlu; Liang, Zongsuo

    2013-07-01

    Salvia miltiorrhiza Bunge (Lamiaceae) root, generally called Danshen, is an important herb in Chinese medicine widely used for treatment of various diseases. Phenolic acids in S. miltiorrhiza, as important effective compounds, have become a new research focus in plant secondary metabolism in recent years. This review summarizes the recent advances in the regulation of water-soluble phenolic acid biosynthesis in S. miltiorrhiza via regulators at molecular level, such as the phenylalanine ammonia-lyase gene (PAL), cinnamic acid 4-hydroxylase gene (C4H), 4-coumarate-CoA ligase gene (4CL), tyrosine aminotransferase gene (TAT), 4-hydroxyphenylpyruvate reductase gene (HPPR), 4-hydroxyphenylpyruvated dioxygenase gene (HPPD), hydroxycinnamoyl-CoA:hydroxyphenyllactate hydroxycinnamoyl transferase-like gene (RAS-like), and v-myb avian myeloblastosis viral oncogene homolog 4 gene (MYB4), and production of anthocyanin pigmentation 1 gene (AtPAP1), and via regulators at cell level, such as methyl jasmonate, salicylic acid, abscisic acid, polyamines, metal ions, hydrogen peroxide (H₂O₂), ultraviolet-B radiation, and yeast elicitor.

  1. Gut microbiota, cirrhosis and alcohol regulate bile acid metabolism in the gut

    PubMed Central

    Ridlon, Jason M.; Kang, Dae-Joong; Hylemon, Phillip B.; Bajaj, Jasmohan S

    2015-01-01

    The understanding of the complex role of the bile acid-gut microbiome axis in health and disease processes is evolving rapidly. Our focus revolves around the interaction of the gut microbiota with liver diseases, especially cirrhosis. The bile acid pool size has recently been shown to be a function of microbial metabolism of bile acid and regulation of the microbiota by bile acids is important in the development and progression of several liver diseases. Humans produce a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of FXR in intestine and liver. Microbes use bile acids, and via FXR signaling this results in a smaller, unconjugated hydrophobic bile acid pool. This equilibrium is critical to maintain health. The challenge is to examine the manifold functions of gut bile acids as modulators of antibiotic, probiotic and disease progression in cirrhosis, metabolic syndrome and alcohol use. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. With advancing liver disease and cirrhosis, there is dysbiosis in the fecal, ileal and colonic mucosa, in addition to a decrease in bile acid concentration in the intestine due to the liver problems. This results in a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa and increasing production of deoxycholic acid (DCA). Alcohol intake speeds up these processes in the subjects with and without cirrhosis without significant FXR feedback. Taken together, these pathways can impact intestinal and systemic inflammation while worsening dysbiosis. The interaction between bile acids, alcohol, cirrhosis and dysbiosis is an important relationship that influences intestinal and systemic inflammation, which in turn determines progression of the overall disease process. These interactions and the impact of commonly used therapies for liver disease can provide insight into the pathogenesis

  2. Gut microbiota, cirrhosis, and alcohol regulate bile acid metabolism in the gut.

    PubMed

    Ridlon, Jason M; Kang, Dae-Joong; Hylemon, Phillip B; Bajaj, Jasmohan S

    2015-01-01

    The understanding of the complex role of the bile acid-gut microbiome axis in health and disease processes is evolving rapidly. Our focus revolves around the interaction of the gut microbiota with liver diseases, especially cirrhosis. The bile acid pool size has recently been shown to be a function of microbial metabolism of bile acid, and regulation of the microbiota by bile acids is important in the development and progression of several liver diseases. Humans produce a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of farnesoid X receptor (FXR) in the intestine and liver. Microbes use bile acids, and via FXR signaling this results in a smaller, unconjugated hydrophobic bile acid pool. This equilibrium is critical to maintain health. The challenge is to examine the manifold functions of gut bile acids as modulators of antibiotic, probiotic, and disease progression in cirrhosis, metabolic syndrome, and alcohol use. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. With advancing liver disease and cirrhosis, there is dysbiosis in the fecal, ileal, and colonic mucosa, in addition to a decrease in bile acid concentration in the intestine due to the liver problems. This results in a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa, and increasing production of deoxycholic acid. Alcohol intake speeds up these processes in the subjects with and without cirrhosis without significant FXR feedback. Taken together, these pathways can impact intestinal and systemic inflammation while worsening dysbiosis. The interaction between bile acids, alcohol, cirrhosis, and dysbiosis is an important relationship that influences intestinal and systemic inflammation, which in turn determines progression of the overall disease process. These interactions and the impact of commonly used therapies for liver disease can provide

  3. Ozone pollution and ozone biomonitoring in European cities Part II. Ozone-induced plant injury and its relationship with descriptors of ozone pollution

    NASA Astrophysics Data System (ADS)

    Klumpp, Andreas; Ansel, Wolfgang; Klumpp, Gabriele; Vergne, Phillippe; Sifakis, Nicolas; Sanz, María José; Rasmussen, Stine; Ro-Poulsen, Helge; Ribas, Àngela; Peñuelas, Josep; Kambezidis, Harry; He, Shang; Garrec, Jean Pierre; Calatayud, Vicent

    Within the scope of a biomonitoring study conducted in twelve urban agglomerations in eight European countries, the ozone-sensitive bioindicator plant Nicotiana tabacum cv. Bel-W3 was employed in order to assess the occurrence of phytotoxic ozone effects at urban, suburban, rural and traffic-exposed sites. The tobacco plants were exposed to ambient air for biweekly periods at up to 100 biomonitoring sites from 2000 to 2002. Special emphasis was placed upon methodological standardisation of plant cultivation, field exposure and injury assessment. Ozone-induced leaf injury showed a clearly increasing gradient from northern and northwestern Europe to central and southern European locations. The strongest ozone impact occurred at the exposure sites in Lyon and Barcelona, while in Edinburgh, Sheffield, Copenhagen and Düsseldorf only weak to moderate ozone effects were registered. Between-site differences within local networks were relatively small, but seasonal and inter-annual differences were strong due to the variability of meteorological conditions and related ozone concentrations. The 2001 data revealed a significant relationship between foliar injury degree and various descriptors of ozone pollution such as mean value, AOT20 and AOT40. Examining individual sites of the local monitoring networks separately, however, yielded noticeable differences. Some sites showed no association between ozone pollution and ozone-induced effects, whereas others featured almost linear relationships. This is because the actual ozone flux into the leaf, which is modified by various environmental factors, rather than ambient ozone concentration determines the effects on plants. The advantage of sensitive bioindicators like tobacco Bel-W3 is that the impact of the effectively absorbed ozone dose can directly be measured.

  4. Structure-dependent effects of pyridine derivatives on mechanisms of intestinal fatty acid uptake: regulation of nicotinic acid receptor and fatty acid transporter expression.

    PubMed

    Riedel, Annett; Lang, Roman; Rohm, Barbara; Rubach, Malte; Hofmann, Thomas; Somoza, Veronika

    2014-07-01

    Pyridines are widely distributed in foods. Nicotinic acid (NA), a carboxylated pyridine derivative, inhibits lipolysis in adipocytes by activation of the orphan NA receptor (HM74A) and is applied to treat hyperlipidemia. However, knowledge on the impact of pyridine derivatives on intestinal lipid metabolism is scarce. This study was performed to identify the structural determinants of pyridines for their effects on fatty acid uptake in enterocyte-like Caco-2 cells and to elucidate the mechanisms of action. The impact of 17 pyridine derivatives on fatty acid uptake was tested. Multiple regression analysis revealed the presence of a methyl group to be the structural determinant at 0.1 mM, whereas at 1 mM, the presence of a carboxylic group and the N-methylation presented further structural characteristics to affect the fatty acid uptake. NA, showing a stimulating effect on FA uptake, and N-methyl-4-phenylpyridinium (MPP), inhibiting FA uptake, were selected for mechanistic studies. Gene expression of the fatty acid transporters CD36, FATP2 and FATP4, and the lipid metabolism regulating transcription factors peroxisome proliferator-activated receptor (PPAR) α and PPARγ was up-regulated upon NA treatment. Caco-2 cells were demonstrated to express the low-affinity NA receptor HM74 of which the gene expression was up-regulated upon NA treatment. We hypothesize that the NA-induced fatty acid uptake might result from NA receptor activation and related intracellular signaling cascades. In contrast, MPP increased transepithelial electrical resistance. We therefore conclude that NA and MPP, both sharing the pyridine motif core, exhibit their contrary effects on intestinal FA uptake by activation of different mechanisms. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Retinoic acids up-regulate functional eosinophil-driving receptor CCR3.

    PubMed

    Ueki, S; Nishikawa, J; Yamauchi, Y; Konno, Y; Tamaki, M; Itoga, M; Kobayashi, Y; Takeda, M; Moritoki, Y; Ito, W; Chihara, J

    2013-07-01

    Eotaxins and their receptor CCR3 have a definitive role for tissue accumulation of eosinophils both under homeostatic and pathologic conditions. However, physiological stimuli that can up-regulate CCR3 in blood-derived human eosinophils have not been recognized. As a prior gene microarray study revealed up-regulation of CCR3 in eosinophils stimulated with retinoic acids (RAs), the expression of functional CCR3 was examined. We found that 9-cis RA and all-trans RA (ATRA) significantly induced surface CCR3 expression regardless of the presence of IL-3 or IL-5. Pharmacological manipulations with receptor-specific agonists and antagonists indicated that retinoic acid receptor-α activation is critical for CCR3 up-regulation. RA-induced CCR3 was associated with its functional capacity, in terms of the calcium mobilization and chemotactic response to eotaxin-1 (CCL11). Our study suggests an important role of vitamin A derivatives in the tissue accumulation of eosinophils.

  6. The role of Zic transcription factors in regulating hindbrain retinoic acid signaling

    PubMed Central

    2013-01-01

    Background The reiterated architecture of cranial motor neurons aligns with the segmented structure of the embryonic vertebrate hindbrain. Anterior-posterior identity of cranial motor neurons depends, in part, on retinoic acid signaling levels. The early vertebrate embryo maintains a balance between retinoic acid synthetic and degradative zones on the basis of reciprocal expression domains of the retinoic acid synthesis gene aldhehyde dehydrogenase 1a2 (aldh1a2) posteriorly and the oxidative gene cytochrome p450 type 26a1 (cyp26a1) in the forebrain, midbrain, and anterior hindbrain. Results This manuscript investigates the role of zinc finger of the cerebellum (zic) transcription factors in regulating levels of retinoic acid and differentiation of cranial motor neurons. Depletion of zebrafish Zic2a and Zic2b results in a strong downregulation of aldh1a2 expression and a concomitant reduction in activity of a retinoid-dependent transgene. The vagal motor neuron phenotype caused by loss of Zic2a/2b mimics a depletion of Aldh1a2 and is rescued by exogenously supplied retinoic acid. Conclusion Zic transcription factors function in patterning hindbrain motor neurons through their regulation of embryonic retinoic acid signaling. PMID:23937294

  7. Docosahexaenoic acid regulates gene expression in HUVEC cells treated with polycyclic aromatic hydrocarbons.

    PubMed

    Gdula-Argasińska, Joanna; Czepiel, Jacek; Totoń-Żurańska, Justyna; Jurczyszyn, Artur; Perucki, William; Wołkow, Paweł

    2015-07-16

    The molecular mechanism of inflammation and carcinogenesis induced by exposure of polycyclic aromatic hydrocarbons (PAHs) is not clearly understood. Our study was undertaken due to the strong pro-carcinogenic potential and reactivity of PAH-metabolites, as well as the susceptibility of polyunsaturated fatty acids to oxidation. The aim of this study was to evaluate the pro- or anti-inflammatory impact of n-3 docosahexaenoic acid on human primary umbilical vein endothelial cells (HUVEC) exposed to polycyclic aromatic hydrocarbons. We analysed the influence of docosahexaenoic acid (DHA) and/or PAHs supplementation on the fatty acid profile of cell membranes, on cyclooxygenase-2 (COX-2), aryl hydrocarbon receptor (AHR), and glutathione S transferase Mu1 (GSTM1) protein expression as well as on the prostaglandin synthase 2 (PTGS2), AHR, GSTM1, PLA2G4A, and cytochrome P450 CYP1A1 gene expression. We observed that COX-2 and AHR protein expression was increased while GSTM1 expression was decreased in cells exposed to DHA and PAHs. Docosahexaenoic acid down-regulated CYP1A1 and up-regulated the AHR and PTGS2 genes. Our findings suggested that DHA contributes significantly to alleviate the harmful effects caused by PAHs in endothelial cells. Moreover, these results suggest that a diet rich in n-3 fatty acids is helpful to reduce the harmful effects of PAHs exposure on human living in heavily polluted areas.

  8. The chromatin remodeler DDM1 promotes hybrid vigor by regulating salicylic acid metabolism.

    PubMed

    Zhang, Qingzhu; Li, Yanqiang; Xu, Tao; Srivastava, Ashish Kumar; Wang, Dong; Zeng, Liang; Yang, Lan; He, Li; Zhang, Heng; Zheng, Zhimin; Yang, Dong-Lei; Zhao, Cheng; Dong, Juan; Gong, Zhizhong; Liu, Renyi; Zhu, Jian-Kang

    2016-01-01

    In plants, hybrid vigor is influenced by genetic and epigenetic mechanisms; however, the molecular pathways are poorly understood. We investigated the potential contributions of epigenetic regulators to heterosis in Arabidposis and found that the chromatin remodeler DECREASED DNA METHYLATION 1 (DDM1) affects early seedling growth heterosis in Col/C24 hybrids. ddm1 mutants showed impaired heterosis and increased expression of non-additively expressed genes related to salicylic acid metabolism. Interestingly, our data suggest that salicylic acid is a hormetic regulator of seedling growth heterosis, and that hybrid vigor arises from crosses that produce optimal salicylic acid levels. Although DNA methylation failed to correlate with differential non-additively expressed gene expression, we uncovered DDM1 as an epigenetic link between salicylic acid metabolism and heterosis, and propose that the endogenous salicylic acid levels of parental plants can be used to predict the heterotic outcome. Salicylic acid protects plants from pathogens and abiotic stress. Thus, our findings suggest that stress-induced hormesis, which has been associated with increased longevity in other organisms, may underlie specific hybrid vigor traits.

  9. Salvianolic acid B inhibits mitochondrial dysfunction by up-regulating mortalin

    PubMed Central

    Liu, Yunxia; Hu, Yingying; E, Qiukai; Zuo, Ji; Yang, Ling; Liu, Wen

    2017-01-01

    Salvianolic acid B is an antioxidative ingredient derived from Radix Salviae miltiorrhizae that has been widely used to treat liver diseases. However, the therapeutic mechanism underlying Salvianolic acid B has remained largely unknown. Our studies verified that Salvianolic acid B efficiently blocked mitochondrial deformation and dysfunction induced by H2O2 in the human hepatocyte cell line HL7702. Mortalin, a mitochondrial molecular chaperone, maintains mitochondrial morphology stabilization and function integrity. Previous results showed that mortalin overexpression has been observed in hematoma carcinoma cells and that mortalin maintains mitochondrial homeostasis and antagonizes oxidative stress damage. We found that Salvianolic acid B significantly up-regulated mortalin protein expression levels. In addition, Salvianolic acid B lost the function of preventing mitochondrial deformation and dysfunction induced by oxidative stress under mortalin knockdown conditions. We further found that mortalin overexpression increases the mRNA expression of mitofusin-related factor Mfn1 and mitofission-related factor hFis1. In conclusion, Salvianolic acid B maintains the mitochondrial structure stabilization and functional integrity by up-regulating mortalin, which may be associated with increased mitofusin factor Mfn1 and reduced mitofission factor hFis1. PMID:28251987

  10. Salvianolic acid B inhibits mitochondrial dysfunction by up-regulating mortalin.

    PubMed

    Liu, Yunxia; Hu, Yingying; E, Qiukai; Zuo, Ji; Yang, Ling; Liu, Wen

    2017-03-02

    Salvianolic acid B is an antioxidative ingredient derived from Radix Salviae miltiorrhizae that has been widely used to treat liver diseases. However, the therapeutic mechanism underlying Salvianolic acid B has remained largely unknown. Our studies verified that Salvianolic acid B efficiently blocked mitochondrial deformation and dysfunction induced by H2O2 in the human hepatocyte cell line HL7702. Mortalin, a mitochondrial molecular chaperone, maintains mitochondrial morphology stabilization and function integrity. Previous results showed that mortalin overexpression has been observed in hematoma carcinoma cells and that mortalin maintains mitochondrial homeostasis and antagonizes oxidative stress damage. We found that Salvianolic acid B significantly up-regulated mortalin protein expression levels. In addition, Salvianolic acid B lost the function of preventing mitochondrial deformation and dysfunction induced by oxidative stress under mortalin knockdown conditions. We further found that mortalin overexpression increases the mRNA expression of mitofusin-related factor Mfn1 and mitofission-related factor hFis1. In conclusion, Salvianolic acid B maintains the mitochondrial structure stabilization and functional integrity by up-regulating mortalin, which may be associated with increased mitofusin factor Mfn1 and reduced mitofission factor hFis1.

  11. Fatty acid esters produced by Lasiodiplodia theobromae function as growth regulators in tobacco seedlings.

    PubMed

    Uranga, Carla C; Beld, Joris; Mrse, Anthony; Córdova-Guerrero, Iván; Burkart, Michael D; Hernández-Martínez, Rufina

    2016-04-01

    The Botryosphaeriaceae are a family of trunk disease fungi that cause dieback and death of various plant hosts. This work sought to characterize fatty acid derivatives in a highly virulent member of this family, Lasiodiplodia theobromae. Nuclear magnetic resonance and gas chromatography-mass spectrometry of an isolated compound revealed (Z, Z)-9,12-ethyl octadecadienoate, (trivial name ethyl linoleate), as one of the most abundant fatty acid esters produced by L. theobromae. A variety of naturally produced esters of fatty acids were identified in Botryosphaeriaceae. In comparison, the production of fatty acid esters in the soil-borne tomato pathogen Fusarium oxysporum, and the non-phytopathogenic fungus Trichoderma asperellum was found to be limited. Ethyl linoleate, ethyl hexadecanoate (trivial name ethyl palmitate), and ethyl octadecanoate, (trivial name ethyl stearate), significantly inhibited tobacco seed germination and altered seedling leaf growth patterns and morphology at the highest concentration (0.2 mg/mL) tested, while ethyl linoleate and ethyl stearate significantly enhanced growth at low concentrations, with both still inducing growth at 98 ng/mL. This work provides new insights into the role of naturally esterified fatty acids from L. theobromae as plant growth regulators with similar activity to the well-known plant growth regulator gibberellic acid. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. The chromatin remodeler DDM1 promotes hybrid vigor by regulating salicylic acid metabolism

    PubMed Central

    Zhang, Qingzhu; Li, Yanqiang; Xu, Tao; Srivastava, Ashish Kumar; Wang, Dong; Zeng, Liang; Yang, Lan; He, Li; Zhang, Heng; Zheng, Zhimin; Yang, Dong-Lei; Zhao, Cheng; Dong, Juan; Gong, Zhizhong; Liu, Renyi; Zhu, Jian-Kang

    2016-01-01

    In plants, hybrid vigor is influenced by genetic and epigenetic mechanisms; however, the molecular pathways are poorly understood. We investigated the potential contributions of epigenetic regulators to heterosis in Arabidposis and found that the chromatin remodeler DECREASED DNA METHYLATION 1 (DDM1) affects early seedling growth heterosis in Col/C24 hybrids. ddm1 mutants showed impaired heterosis and increased expression of non-additively expressed genes related to salicylic acid metabolism. Interestingly, our data suggest that salicylic acid is a hormetic regulator of seedling growth heterosis, and that hybrid vigor arises from crosses that produce optimal salicylic acid levels. Although DNA methylation failed to correlate with differential non-additively expressed gene expression, we uncovered DDM1 as an epigenetic link between salicylic acid metabolism and heterosis, and propose that the endogenous salicylic acid levels of parental plants can be used to predict the heterotic outcome. Salicylic acid protects plants from pathogens and abiotic stress. Thus, our findings suggest that stress-induced hormesis, which has been associated with increased longevity in other organisms, may underlie specific hybrid vigor traits. PMID:27551435

  13. Fatty acid regulates gene expression and growth of human prostate cancer PC-3 cells

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Chen, Y.; Tjandrawinata, R. R.

    2001-01-01

    It has been proposed that the omega-6 fatty acids increase the rate of tumor growth. Here we test that hypothesis in the PC-3 human prostate tumor. We found that the essential fatty acids, linoleic acid (LA) and arachidonic acid (AA), and the AA metabolite PGE(2) stimulate tumor growth while oleic acid (OA) and the omega-3 fatty acid, eicosapentaenoic acid (EPA) inhibited growth. In examining the role of AA in growth response, we extended our studies to analyze changes in early gene expression induced by AA. We demonstrate that c-fos expression is increased within minutes of addition in a dose-dependent manner. Moreover, the immediate early gene cox-2 is also increased in the presence of AA in a dose-dependent manner, while the constitutive cox-1 message was not increased. Three hours after exposure to AA, the synthesis of PGE(2) via COX-2 was also increased. Previous studies have demonstrated that AA was primarily delivered by low density lipoprotein (LDL) via its receptor (LDLr). Since it is known that hepatomas, acute myelogenous leukemia and colorectal tumors lack normal cholesterol feedback, we examined the role of the LDLr in growth regulation of the PC-3 prostate cancer cells. Analysis of ldlr mRNA expression and LDLr function demonstrated that human PC-3 prostate cancer cells lack normal feedback regulation. While exogenous LDL caused a significant stimulation of cell growth and PGE(2) synthesis, no change was seen in regulation of the LDLr by LDL. Taken together, these data show that normal cholesterol feedback of ldlr message and protein is lost in prostate cancer. These data suggest that unregulated over-expression of LDLr in tumor cells would permit increased availability of AA, which induces immediate early genes c-fos and cox-2 within minutes of uptake.

  14. Fatty acid regulates gene expression and growth of human prostate cancer PC-3 cells

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Chen, Y.; Tjandrawinata, R. R.

    2001-01-01

    It has been proposed that the omega-6 fatty acids increase the rate of tumor growth. Here we test that hypothesis in the PC-3 human prostate tumor. We found that the essential fatty acids, linoleic acid (LA) and arachidonic acid (AA), and the AA metabolite PGE(2) stimulate tumor growth while oleic acid (OA) and the omega-3 fatty acid, eicosapentaenoic acid (EPA) inhibited growth. In examining the role of AA in growth response, we extended our studies to analyze changes in early gene expression induced by AA. We demonstrate that c-fos expression is increased within minutes of addition in a dose-dependent manner. Moreover, the immediate early gene cox-2 is also increased in the presence of AA in a dose-dependent manner, while the constitutive cox-1 message was not increased. Three hours after exposure to AA, the synthesis of PGE(2) via COX-2 was also increased. Previous studies have demonstrated that AA was primarily delivered by low density lipoprotein (LDL) via its receptor (LDLr). Since it is known that hepatomas, acute myelogenous leukemia and colorectal tumors lack normal cholesterol feedback, we examined the role of the LDLr in growth regulation of the PC-3 prostate cancer cells. Analysis of ldlr mRNA expression and LDLr function demonstrated that human PC-3 prostate cancer cells lack normal feedback regulation. While exogenous LDL caused a significant stimulation of cell growth and PGE(2) synthesis, no change was seen in regulation of the LDLr by LDL. Taken together, these data show that normal cholesterol feedback of ldlr message and protein is lost in prostate cancer. These data suggest that unregulated over-expression of LDLr in tumor cells would permit increased availability of AA, which induces immediate early genes c-fos and cox-2 within minutes of uptake.

  15. Probing the Sophisticated Synergistic Allosteric Regulation of Aromatic Amino Acid Biosynthesis in Mycobacterium tuberculosis Using ᴅ-Amino Acids.

    PubMed

    Reichau, Sebastian; Blackmore, Nicola J; Jiao, Wanting; Parker, Emily J

    2016-01-01

    Chirality plays a major role in recognition and interaction of biologically important molecules. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of the shikimate pathway, which is responsible for the synthesis of aromatic amino acids in bacteria and plants, and a potential target for the development of antibiotics and herbicides. DAH7PS from Mycobacterium tuberculosis (MtuDAH7PS) displays an unprecedented complexity of allosteric regulation, with three interdependent allosteric binding sites and a ternary allosteric response to combinations of the aromatic amino acids l-Trp, l-Phe and l-Tyr. In order to further investigate the intricacies of this system and identify key residues in the allosteric network of MtuDAH7PS, we studied the interaction of MtuDAH7PS with aromatic amino acids that bear the non-natural d-configuration, and showed that the d-amino acids do not elicit an allosteric response. We investigated the binding mode of d-amino acids using X-ray crystallography, site directed mutagenesis and isothermal titration calorimetry. Key differences in the binding mode were identified: in the Phe site, a hydrogen bond between the amino group of the allosteric ligands to the side chain of Asn175 is not established due to the inverted configuration of the ligands. In the Trp site, d-Trp forms no interaction with the main chain carbonyl group of Thr240 and less favourable interactions with Asn237 when compared to the l-Trp binding mode. Investigation of the MtuDAH7PSN175A variant further supports the hypothesis that the lack of key interactions in the binding mode of the aromatic d-amino acids are responsible for the absence of an allosteric response, which gives further insight into which residues of MtuDAH7PS play a key role in the transduction of the allosteric signal.

  16. Probing the Sophisticated Synergistic Allosteric Regulation of Aromatic Amino Acid Biosynthesis in Mycobacterium tuberculosis Using ᴅ-Amino Acids

    PubMed Central

    Reichau, Sebastian; Blackmore, Nicola J.; Jiao, Wanting; Parker, Emily J.

    2016-01-01

    Chirality plays a major role in recognition and interaction of biologically important molecules. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of the shikimate pathway, which is responsible for the synthesis of aromatic amino acids in bacteria and plants, and a potential target for the development of antibiotics and herbicides. DAH7PS from Mycobacterium tuberculosis (MtuDAH7PS) displays an unprecedented complexity of allosteric regulation, with three interdependent allosteric binding sites and a ternary allosteric response to combinations of the aromatic amino acids l-Trp, l-Phe and l-Tyr. In order to further investigate the intricacies of this system and identify key residues in the allosteric network of MtuDAH7PS, we studied the interaction of MtuDAH7PS with aromatic amino acids that bear the non-natural d-configuration, and showed that the d-amino acids do not elicit an allosteric response. We investigated the binding mode of d-amino acids using X-ray crystallography, site directed mutagenesis and isothermal titration calorimetry. Key differences in the binding mode were identified: in the Phe site, a hydrogen bond between the amino group of the allosteric ligands to the side chain of Asn175 is not established due to the inverted configuration of the ligands. In the Trp site, d-Trp forms no interaction with the main chain carbonyl group of Thr240 and less favourable interactions with Asn237 when compared to the l-Trp binding mode. Investigation of the MtuDAH7PSN175A variant further supports the hypothesis that the lack of key interactions in the binding mode of the aromatic d-amino acids are responsible for the absence of an allosteric response, which gives further insight into which residues of MtuDAH7PS play a key role in the transduction of the allosteric signal. PMID:27128682

  17. Amino Acids Regulate mTORC1 by an Obligate Two-step Mechanism.

    PubMed

    Dyachok, Julia; Earnest, Svetlana; Iturraran, Erica N; Cobb, Melanie H; Ross, Elliott M

    2016-10-21

    The mechanistic target of rapamycin complex 1 (mTORC1) coordinates cell growth with its nutritional, hormonal, energy, and stress status. Amino acids are critical regulators of mTORC1 that permit other inputs to mTORC1 activity. However, the roles of individual amino acids and their interactions in mTORC1 activation are not well understood. Here we demonstrate that activation of mTORC1 by amino acids includes two discrete and separable steps: priming and activation. Sensitizing mTORC1 activation by priming amino acids is a prerequisite for subsequent stimulation of mTORC1 by activating amino acids. Priming is achieved by a group of amino acids that includes l-asparagine, l-glutamine, l-threonine, l-arginine, l-glycine, l-proline, l-serine, l-alanine, and l-glutamic acid. The group of activating amino acids is dominated by l-leucine but also includes l-methionine, l-isoleucine, and l-valine. l-Cysteine predominantly inhibits priming but not the activating step. Priming and activating steps differ in their requirements for amino acid concentration and duration of treatment. Priming and activating amino acids use mechanisms that are distinct both from each other and from growth factor signaling. Neither step requires intact tuberous sclerosis complex of proteins to activate mTORC1. Concerted action of priming and activating amino acids is required to localize mTORC1 to lysosomes and achieve its activation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Regulation of xanthine dehydrogensase gene expression and uric acid production in human airway epithelial cells.

    PubMed

    Huff, Ryan D; Hsu, Alan C-Y; Nichol, Kristy S; Jones, Bernadette; Knight, Darryl A; Wark, Peter A B; Hansbro, Philip M; Hirota, Jeremy A

    2017-01-01

    The airway epithelium is a physical and immunological barrier that protects the pulmonary system from inhaled environmental insults. Uric acid has been detected in the respiratory tract and can function as an antioxidant or damage associated molecular pattern. We have demonstrated that human airway epithelial cells are a source of uric acid. Our hypothesis is that uric acid production by airway epithelial cells is induced by environmental stimuli associated with chronic respiratory diseases. We therefore examined how airway epithelial cells regulate uric acid production. Allergen and cigarette smoke mouse models were performed using house dust mite (HDM) and cigarette smoke exposure, respectively, with outcome measurements of lung uric acid levels. Primary human airway epithelial cells isolated from clinically diagnosed patients with asthma and chronic obstructive pulmonary disease (COPD) were grown in submerged cultures and compared to age-matched healthy controls for uric acid release. HBEC-6KT cells, a human airway epithelial cell line, were grown under submerged monolayer conditions for mechanistic and gene expression studies. HDM, but not cigarette smoke exposure, stimulated uric acid production in vivo and in vitro. Primary human airway epithelial cells from asthma, but not COPD patients, displayed elevated levels of extracellular uric acid in culture. In HBEC-6KT, production of uric acid was sensitive to the xanthine dehydrogenase (XDH) inhibitor, allopurinol, and the ATP Binding Cassette C4 (ABCC4) inhibitor, MK-571. Lastly, the pro-inflammatory cytokine combination of TNF-α and IFN-γ elevated extracellular uric acid levels and XDH gene expression in HBEC-6KT cells. Our results suggest that the active production of uric acid from human airway epithelial cells may be intrinsically altered in asthma and be further induced by pro-inflammatory cytokines.

  19. Uncovering co-expression gene network modules regulating fruit acidity in diverse apples.

    PubMed

    Bai, Yang; Dougherty, Laura; Cheng, Lailiang; Zhong, Gan-Yuan; Xu, Kenong

    2015-08-16

    Acidity is a major contributor to fruit quality. Several organic acids are present in apple fruit, but malic acid is predominant and determines fruit acidity. The trait is largely controlled by the Malic acid (Ma) locus, underpinning which Ma1 that putatively encodes a vacuolar aluminum-activated malate transporter1 (ALMT1)-like protein is a strong candidate gene. We hypothesize that fruit acidity is governed by a gene network in which Ma1 is key member. The goal of this study is to identify the gene network and the potential mechanisms through which the network operates. Guided by Ma1, we analyzed the transcriptomes of mature fruit of contrasting acidity from six apple accessions of genotype Ma_ (MaMa or Mama) and four of mama using RNA-seq and identified 1301 fruit acidity associated genes, among which 18 were most significant acidity genes (MSAGs). Network inferring using weighted gene co-expression network analysis (WGCNA) revealed five co-expression gene network modules of significant (P < 0.001) correlation with malate. Of these, the Ma1 containing module (Turquoise) of 336 genes showed the highest correlation (0.79). We also identified 12 intramodular hub genes from each of the five modules and 18 enriched gene ontology (GO) terms and MapMan sub-bines, including two GO terms (GO:0015979 and GO:0009765) and two MapMap sub-bins (1.3.4 and 1.1.1.1) related to photosynthesis in module Turquoise. Using Lemon-Tree algorithms, we identified 12 regulator genes of probabilistic scores 35.5-81.0, including MDP0000525602 (a LLR receptor kinase), MDP0000319170 (an IQD2-like CaM binding protein) and MDP0000190273 (an EIN3-like transcription factor) of greater interest for being one of the 18 MSAGs or one of the 12 intramodular hub genes in Turquoise, and/or a regulator to the cluster containing Ma1. The most relevant finding of this study is the identification of the MSAGs, intramodular hub genes, enriched photosynthesis related processes, and regulator genes in a

  20. The effects of trans-fatty acids on TAG regulation in mice depend on dietary unsaturated fatty acids.

    PubMed

    Saín, Juliana; González, Marcela Aída; Lavandera, Jimena Verónica; Scalerandi, María Victoria; Bernal, Claudio Adrián

    2016-08-01

    The aim of this study was to investigate the effects of trans-fatty acids (TFA) on liver and serum TAG regulation in mice fed diets containing different proportions of n-3, n-6 and n-9 unsaturated fatty acids (UFA) from olive (O), maize (C) or rapeseed (R) oils partially substituted or not with TFA (Ot, Ct and Rt, respectively). Male CF1 mice were fed (30 d) one of these diets. The effects of the partial substitution (1 %, w/w) of different UFA with TFA on the activity and expression of hepatic enzymes involved in lipogenesis and fatty acids oxidation were evaluated, as well as their transcription factor expressions. Some of the mechanisms involved in the serum TAG regulation, hepatic VLDL rich in TAG (VLDL-TAG) secretion rate and lipoprotein lipase (LPL) activity were assessed. In liver, TFA induced an increase in TAG content in the Ot and Rt groups, and this effect was associated with an imbalance between lipogenesis and β-oxidation. In the Ot group, exacerbated lipogenesis may be one of the mechanisms responsible for the liver steatosis induced by TFA, whereas in Rt it has been related to a decreased β-oxidation, compared with their respective controls. The enhanced hepatic VLDL-TAG secretion in the Ot and Rt groups was compensated with a differential removal of TAG by LPL enzyme in extrahepatic tissues, leading to unchanged serum TAG levels. In brief, the effects of low levels of TFA on liver and serum TAG regulation in mice depend on the dietary proportions of n-3, n-6 and n-9 UFA.

  1. Modulation of organic acids and sugar content in tomato fruits by an abscisic acid-regulated transcription factor.

    PubMed

    Bastías, Adriana; López-Climent, María; Valcárcel, Mercedes; Rosello, Salvador; Gómez-Cadenas, Aurelio; Casaretto, José A

    2011-03-01

    Growing evidence suggests that the phytohormone abscisic acid (ABA) plays a role in fruit development. ABA signaling components of developmental programs and responses to stress conditions include the group of basic leucine zipper transcriptional activators known as ABA-response element binding factors (AREBs/ABFs). AREB transcription factors mediate ABA-regulated gene expression involved in desiccation tolerance and are expressed mainly in seeds and in vegetative tissues under stress; however, they are also expressed in some fruits such as tomato. In order to get an insight into the role of ABA signaling in fruit development, the expression of two AREB-like factors were investigated during different developmental stages. In addition, tomato transgenic lines that overexpress and downregulate one AREB-like transcription factor, SlAREB1, were used to determine its effect on the levels of some metabolites determining fruit quality. Higher levels of citric acid, malic acid, glutamic acid, glucose and fructose were observed in SlAREB1-overexpressing lines compared with those in antisense suppression lines in red mature fruit pericarp. The higher hexose concentration correlated with increased expression of genes encoding a vacuolar invertase (EC 3.2.1.26) and a sucrose synthase (EC 2.4.1.13). No significant changes were found in ethylene content which agrees with the normal ripening phenotype observed in transgenic fruits. These results suggest that an AREB-mediated ABA signal affects the metabolism of these compounds during the fruit developmental program. Copyright © Physiologia Plantarum 2010.

  2. Basic aspects of tumor cell fatty acid-regulated signaling and transcription factors.

    PubMed

    Comba, Andrea; Lin, Yi-Hui; Eynard, Aldo Renato; Valentich, Mirta Ana; Fernandez-Zapico, Martín Ernesto; Pasqualini, Marìa Eugenia

    2011-12-01

    This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases, cyclooxygenases, and cytochrome P-450, seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator-activated receptors or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C) and other transcription factors (nuclear factor kappa B and sterol regulatory element binding protein). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer and provide insight into the development of new therapeutic strategies for a better management of whole body lipid metabolism.

  3. Comparative Genomics of Regulation of Fatty Acid and Branched-Chain Amino Acid Utilization in Proteobacteria▿ †

    PubMed Central

    Kazakov, Alexey E.; Rodionov, Dmitry A.; Alm, Eric; Arkin, Adam Paul; Dubchak, Inna; Gelfand, Mikhail S.

    2009-01-01

    Bacteria can use branched-chain amino acids (ILV, i.e., isoleucine, leucine, valine) and fatty acids (FAs) as sole carbon and energy sources converting ILV into acetyl-coenzyme A (CoA), propanoyl-CoA, and propionyl-CoA, respectively. In this work, we used the comparative genomic approach to identify candidate transcriptional factors and DNA motifs that control ILV and FA utilization pathways in proteobacteria. The metabolic regulons were characterized based on the identification and comparison of candidate transcription factor binding sites in groups of phylogenetically related genomes. The reconstructed ILV/FA regulatory network demonstrates considerable variability and involves six transcriptional factors from the MerR, TetR, and GntR families binding to 11 distinct DNA motifs. The ILV degradation genes in gamma- and betaproteobacteria are regulated mainly by a novel regulator from the MerR family (e.g., LiuR in Pseudomonas aeruginosa) (40 species); in addition, the TetR-type regulator LiuQ was identified in some betaproteobacteria (eight species). Besides the core set of ILV utilization genes, the LiuR regulon in some lineages is expanded to include genes from other metabolic pathways, such as the glyoxylate shunt and glutamate synthase in Shewanella species. The FA degradation genes are controlled by four regulators including FadR in gammaproteobacteria (34 species), PsrA in gamma- and betaproteobacteria (45 species), FadP in betaproteobacteria (14 species), and LiuR orthologs in alphaproteobacteria (22 species). The remarkable variability of the regulatory systems associated with the FA degradation pathway is discussed from functional and evolutionary points of view. PMID:18820024

  4. Regulation of epinasty induced by 2,4-dichlorophenoxyacetic acid in pea and Arabidopsis plants.

    PubMed

    Pazmiño, D M; Rodríguez-Serrano, M; Sanz, M; Romero-Puertas, M C; Sandalio, L M

    2014-07-01

    The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) causes uncontrolled cell division and malformed growth in plants, giving rise to leaf epinasty and stem curvature. In this study, mechanisms involved in the regulation of leaf epinasty induced by 2,4-D were studied using different chemicals involved in reactive oxygen species (ROS) accumulation (diphenyleniodonium, butylated hydroxyanisole, EDTA, allopurinol), calcium channels (LaCl3), protein phosphorylation (cantharidin, wortmannin) and ethylene emission/perception (aminoethoxyvinyl glycine, AgNO3). The effect of these compounds on the epinasty induced by 2,4-D was analysed in shoots and leaf strips from pea plants. For further insight into the effect of 2,4-D, studies were also made in Arabidopsis mutants deficient in ROS production (rbohD, rbohF, xdh), ethylene (ein 3-1, ctr 1-1, etr 1-1), abscisic acid (aba 3.1), and jasmonic acid (coi 1.1, jar 1.1, opr 3) pathways. The results suggest that ROS production, mainly ·OH, is essential in the development of epinasty triggered by 2,4-D. Epinasty was also found to be regulated by Ca2+, protein phosphorylation and ethylene, although all these factors act downstream of ROS production. The use of Arabidopsis mutants appears to indicate that abscisic and jasmonic acid are not involved in regulating epinasty, although they could be involved in other symptoms induced by 2,4-D.

  5. Inducible gene expression and environmentally regulated genes in lactic acid bacteria.

    PubMed

    Kok, J

    1996-10-01

    Relatively recently, a number of genes and operons have been identified in lactic acid bacteria that are inducible and respond to environmental factors. Some of these genes/operons had been isolated and analysed because of their importance in the fermentation industry and, consequently, their transcription was studied and found to be regulatable. Examples are the lactose operon, the operon for nisin production, and genes in the proteolytic pathway of Lactococcus lactis, as well as xylose metabolism in Lactobacillus pentosus. Some other operons were specifically targetted with the aim to compare their mode of regulation with known regulatory mechanisms in other well-studied bacteria. These studies, dealing with the biosynthesis of histidine, tryptophan, and of the branched chain amino acids in L. lactis, have given new insights in gene regulation and in the occurrence of auxotrophy in these bacteria. Also, nucleotide sequence analyses of a number of lactococcal bacteriophages was recently initiated to, among other things, specifically learn more about regulation of the phage life cycle. Yet another approach in the analysis of regulated genes is the 'random' selection of genetic elements that respond to environmental stimuli and the first of such sequences from lactic acid bacteria have been identified and characterized. The potential of these regulatory elements in fundamental research and practical (industrial) applications will be discussed.

  6. Chlorogenic acid from coffee beans: evaluating the evidence for a blood pressure-regulating health claim.

    PubMed

    Loader, Tara B; Taylor, Carla G; Zahradka, Peter; Jones, Peter J H

    2017-02-01

    The consumption of coffee has been associated with a number of health benefits, including a reduced risk of cardiovascular disease. Hypertension is an important risk factor for adverse cardiovascular events. Coffee may help reduce blood pressure (BP) in humans, which might be attributable to its polyphenolic compound, chlorogenic acid. The high incidence of hypertension among Canadians underscores the need for new and effective strategies to reduce BP. Dietary interventions may constitute such a strategy, but consumers need to be informed about which foods are most effective for regulating BP. To guide healthy eating, Health Canada permits the use of health claims on the labels of foods that confer health benefits. Currently, there is only one health claim for BP regulation. Additional health claims for foods that assist in BP regulation are therefore warranted. This review provides background information on chlorogenic acid and examines the evidence regarding the use of chlorogenic acid for BP regulation in the context of Health Canada's health claims framework. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  7. A naturally occurring insertion of a single amino acid rewires transcriptional regulation by glucocorticoid receptor isoforms.

    PubMed

    Thomas-Chollier, Morgane; Watson, Lisa C; Cooper, Samantha B; Pufall, Miles A; Liu, Jennifer S; Borzym, Katja; Vingron, Martin; Yamamoto, Keith R; Meijsing, Sebastiaan H

    2013-10-29

    In addition to guiding proteins to defined genomic loci, DNA can act as an allosteric ligand that influences protein structure and activity. Here we compared genome-wide binding, transcriptional regulation, and, using NMR, the conformation of two glucocorticoid receptor (GR) isoforms that differ by a single amino acid insertion in the lever arm, a domain that adopts DNA sequence-specific conformations. We show that these isoforms differentially regulate gene expression levels through two mechanisms: differential DNA binding and altered communication between GR domains. Our studies suggest a versatile role for DNA in both modulating GR activity and also in directing the use of GR isoforms. We propose that the lever arm is a "fulcrum" for bidirectional allosteric signaling, conferring conformational changes in the DNA reading head that influence DNA sequence selectivity, as well as conferring changes in the dimerization domain that connect functionally with remote regulatory surfaces, thereby influencing which genes are regulated and the magnitude of their regulation.

  8. Mig-6 Plays a Critical Role in the Regulation of Cholesterol Homeostasis and Bile Acid Synthesis

    PubMed Central

    Ku, Bon Jeong; Kim, Tae Hoon; Lee, Jae Hee; Buras, Eric D.; White, Lisa D.; Stevens, Robert D.; Ilkayeva, Olga R.; Bain, James R.; Newgard, Christopher B.

    2012-01-01

    The disruption of cholesterol homeostasis leads to an increase in cholesterol levels which results in the development of cardiovascular disease. Mitogen Inducible Gene 6 (Mig-6) is an immediate early response gene that can be induced by various mitogens, stresses, and hormones. To identify the metabolic role of Mig-6 in the liver, we conditionally ablated Mig-6 in the liver using the Albumin-Cre mouse model (Albcre/+Mig-6f/f; Mig-6d/d). Mig-6d/d mice exhibit hepatomegaly and fatty liver. Serum levels of total, LDL, and HDL cholesterol and hepatic lipid were significantly increased in the Mig-6d/d mice. The daily excretion of fecal bile acids was significantly decreased in the Mig-6d/d mice. DNA microarray analysis of mRNA isolated from the livers of these mice showed alterations in genes that regulate lipid metabolism, bile acid, and cholesterol synthesis, while the expression of genes that regulate biliary excretion of bile acid and triglyceride synthesis showed no difference in the Mig-6d/d mice compared to Mig-6f/f controls. These results indicate that Mig-6 plays an important role in cholesterol homeostasis and bile acid synthesis. Mice with liver specific conditional ablation of Mig-6 develop hepatomegaly and increased intrahepatic lipid and provide a novel model system to investigate the genetic and molecular events involved in the regulation of cholesterol homeostasis and bile acid synthesis. Defining the molecular mechanisms by which Mig-6 regulates cholesterol homeostasis will provide new insights into the development of more effective ways for the treatment and prevention of cardiovascular disease. PMID:22912762

  9. Mig-6 plays a critical role in the regulation of cholesterol homeostasis and bile acid synthesis.

    PubMed

    Ku, Bon Jeong; Kim, Tae Hoon; Lee, Jae Hee; Buras, Eric D; White, Lisa D; Stevens, Robert D; Ilkayeva, Olga R; Bain, James R; Newgard, Christopher B; DeMayo, Francesco J; Jeong, Jae-Wook

    2012-01-01

    The disruption of cholesterol homeostasis leads to an increase in cholesterol levels which results in the development of cardiovascular disease. Mitogen Inducible Gene 6 (Mig-6) is an immediate early response gene that can be induced by various mitogens, stresses, and hormones. To identify the metabolic role of Mig-6 in the liver, we conditionally ablated Mig-6 in the liver using the Albumin-Cre mouse model (Alb(cre/+)Mig-6(f/f); Mig-6(d/d)). Mig-6(d/d) mice exhibit hepatomegaly and fatty liver. Serum levels of total, LDL, and HDL cholesterol and hepatic lipid were significantly increased in the Mig-6(d/d) mice. The daily excretion of fecal bile acids was significantly decreased in the Mig-6(d/d) mice. DNA microarray analysis of mRNA isolated from the livers of these mice showed alterations in genes that regulate lipid metabolism, bile acid, and cholesterol synthesis, while the expression of genes that regulate biliary excretion of bile acid and triglyceride synthesis showed no difference in the Mig-6(d/d) mice compared to Mig-6(f/f) controls. These results indicate that Mig-6 plays an important role in cholesterol homeostasis and bile acid synthesis. Mice with liver specific conditional ablation of Mig-6 develop hepatomegaly and increased intrahepatic lipid and provide a novel model system to investigate the genetic and molecular events involved in the regulation of cholesterol homeostasis and bile acid synthesis. Defining the molecular mechanisms by which Mig-6 regulates cholesterol homeostasis will provide new insights into the development of more effective ways for the treatment and prevention of cardiovascular disease.

  10. Hyaluronic acid as capacitation inductor: metabolic changes and membrane-associated adenylate cyclase regulation.

    PubMed

    Fernández, S; Córdoba, M

    2014-12-01

    The aim of this research was to study the effect of hyaluronic acid on bovine cryopreserved spermatozoa compared with heparin as regards the variation of capacitation induction, cellular oxidative metabolism and intracellular signal induced by membrane-associated adenylate cyclase to propose hyaluronic acid as a capacitation inductor. Heparin or hyaluronic acid and lysophosphatidylcholine were used to induce sperm capacitation and acrosome reaction, respectively. 2',5'-dideoxyadenosine was used as a membrane-associated adenylate cyclase inhibitor. The highest percentages of capacitated spermatozoa and live spermatozoa with acrosome integrity were obtained by incubating sperm for 60 min using 1000 μg/ml hyaluronic acid. In these conditions, capacitation induced by hyaluronic acid was lower compared with heparin; nonetheless both glycosaminoglycans promote intracellular changes that allow true acrosome reaction in vitro induced by lysophosphatidylcholine in bovine spermatozoa. Oxygen consumption in heparin-capacitated spermatozoa was significantly higher than in hyaluronic acid-treated spermatozoa. With all treatments, mitochondrial coupling was observed when a specific uncoupler of the respiratory chain was added. The inhibition of membrane-associated adenylate cyclase significantly blocked capacitation induction produced by hyaluronic acid, maintaining a basal sperm oxygen uptake in contrast to heparin effect in which both sperm parameters were inhibited, suggesting that the membrane-associated adenylate cyclase activation is involved in the intracellular signal mechanisms induced by both capacitation inductors, but only regulates mitochondrial oxidative phosphorylation in heparin-capacitated spermatozoa.

  11. Modulation of the mitochondrial large-conductance calcium-regulated potassium channel by polyunsaturated fatty acids.

    PubMed

    Olszewska, Anna; Bednarczyk, Piotr; Siemen, Detlef; Szewczyk, Adam

    2014-10-01

    Polyunsaturated fatty acids (PUFAs) and their metabolites can modulate several biochemical processes in the cell and thus prevent various diseases. PUFAs have a number of cellular targets, including membrane proteins. They can interact with plasma membrane and intracellular potassium channels. The goal of this work was to verify the interaction between PUFAs and the most common and intensively studied mitochondrial large conductance Ca(2+)-regulated potassium channel (mitoBKCa). For this purpose human astrocytoma U87 MG cell lines were investigated using a patch-clamp technique. We analyzed the effects of arachidonic acid (AA); eicosatetraynoic acid (ETYA), which is a non-metabolizable analog of AA; docosahexaenoic acid (DHA); and eicosapentaenoic acid (EPA). The open probability (Po) of the channel did not change significantly after application of 10μM ETYA. Po increased, however, after adding 10μM AA. The application of 30μM DHA or 10μM EPA also increased the Po of the channel. Additionally, the number of open channels in the patch increased in the presence of 30μM EPA. Collectively, our results indicate that PUFAs regulate the BKCa channel from the inner mitochondrial membrane. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Dietary oleic acid regulates hepatic lipogenesis through a liver X receptor-dependent signaling.

    PubMed

    Ducheix, Simon; Montagner, Alexandra; Polizzi, Arnaud; Lasserre, Frédéric; Régnier, Marion; Marmugi, Alice; Benhamed, Fadila; Bertrand-Michel, Justine; Mselli-Lakhal, Laila; Loiseau, Nicolas; Martin, Pascal G; Lobaccaro, Jean-Marc; Ferrier, Laurent; Postic, Catherine; Guillou, Hervé

    2017-01-01

    Olive oil consumption is beneficial for health as it is associated with a decreased prevalence of cancer and cardiovascular diseases. Oleic acid is, by far, the most abundant component of olive oil. Since it can be made through de novo synthesis in animals, it is not an essential fatty acid. While it has become clear that dietary oleic acid regulates many biological processes, the signaling pathway involved in these regulations remains poorly defined. In this work we tested the impact of an oleic acid-rich diet on hepatic gene expression. We were particularly interested in addressing the contribution of Liver X Receptors (LXR) in the control of genes involved in hepatic lipogenesis, an essential process in whole body energy homeostasis. We used wild-type mice and transgenic mice deficient for both α and β Liver X Receptor isoforms (LXR-/-) fed a control or an oleate enriched diet. We observed that hepatic-lipid accumulation was enhanced as well as the expression of lipogenic genes in the liver of wild-type mice fed the oleate enriched diet. In contrast, none of these changes occurred in the liver of LXR-/- mice. Strikingly, oleate-rich diet reduced cholesterolemia in wild-type mice and induced signs of liver inflammation and damage in LXR-/- mice but not in wild-type mice. This work suggests that dietary oleic acid reduces cholesterolemia while promoting LXR-dependent hepatic lipogenesis without detrimental effects to the liver.

  13. Structural evolution of differential amino acid effector regulation in plant chorismate mutases.

    PubMed

    Westfall, Corey S; Xu, Ang; Jez, Joseph M

    2014-10-10

    Chorismate mutase converts chorismate into prephenate for aromatic amino acid biosynthesis. To understand the molecular basis of allosteric regulation in the plant chorismate mutases, we analyzed the three Arabidopsis thaliana chorismate mutase isoforms (AtCM1-3) and determined the x-ray crystal structures of AtCM1 in complex with phenylalanine and tyrosine. Functional analyses show a wider range of effector control in the Arabidopsis chorismate mutases than previously reported. AtCM1 is activated by tryptophan with phenylalanine and tyrosine acting as negative effectors; however, tryptophan, cysteine, and histidine activate AtCM3. AtCM2 is a nonallosteric form. The crystal structure of AtCM1 in complex with tyrosine and phenylalanine identifies differences in the effector sites of the allosterically regulated yeast enzyme and the other two Arabidopsis isoforms. Site-directed mutagenesis of residues in the effector site reveals key features leading to differential effector regulation in these enzymes. In AtCM1, mutations of Gly-213 abolish allosteric regulation, as observed in AtCM2. A second effector site position, Gly-149 in AtCM1 and Asp-132 in AtCM3, controls amino acid effector specificity in AtCM1 and AtCM3. Comparisons of chorismate mutases from multiple plants suggest that subtle differences in the effector site are conserved in different lineages and may lead to specialized regulation of this branch point enzyme.

  14. High capacity for extracellular acid-base regulation in the air-breathing fish Pangasianodon hypophthalmus.

    PubMed

    Damsgaard, Christian; Gam, Le Thi Hong; Tuong, Dang Diem; Thinh, Phan Vinh; Huong Thanh, Do Thi; Wang, Tobias; Bayley, Mark

    2015-05-01

    The evolution of accessory air-breathing structures is typically associated with reduction of the gills, although branchial ion transport remains pivotal for acid-base and ion regulation. Therefore, air-breathing fishes are believed to have a low capacity for extracellular pH regulation during a respiratory acidosis. In the present study, we investigated acid-base regulation during hypercapnia in the air-breathing fish Pangasianodon hypophthalmus in normoxic and hypoxic water at 28-30°C. Contrary to previous studies, we show that this air-breathing fish has a pronounced ability to regulate extracellular pH (pHe) during hypercapnia, with complete metabolic compensation of pHe within 72 h of exposure to hypoxic hypercapnia with CO2 levels above 34 mmHg. The high capacity for pHe regulation relies on a pronounced ability to increase levels of HCO3(-) in the plasma. Our study illustrates the diversity in the physiology of air-breathing fishes, such that generalizations across phylogenies may be difficult.

  15. Regulation of acid resistance by connectors of two-component signal transduction systems in Escherichia coli.

    PubMed

    Eguchi, Yoko; Ishii, Eiji; Hata, Kensuke; Utsumi, Ryutaro

    2011-03-01

    Two-component signal transduction systems (TCSs), utilized extensively by bacteria and archaea, are involved in the rapid adaptation of the organisms to fluctuating environments. A typical TCS transduces the signal by a phosphorelay between the sensor histidine kinase and its cognate response regulator. Recently, small-sized proteins that link TCSs have been reported and are called "connectors." Their physiological roles, however, have remained elusive. SafA (sensor associating factor A) (formerly B1500), a small (65-amino-acid [65-aa]) membrane protein, is among such connectors and links Escherichia coli TCSs EvgS/EvgA and PhoQ/PhoP. Since the activation of the EvgS/EvgA system induces acid resistance, we examined whether the SafA-activated PhoQ/PhoP system is also involved in the acid resistance induced by EvgS/EvgA. Using a constitutively active evgS1 mutant for the activation of EvgS/EvgA, we found that SafA, PhoQ, and PhoP all contributed to the acid resistance phenotype. Moreover, EvgS/EvgA activation resulted in the accumulation of cellular RpoS in the exponential-phase cells in a SafA-, PhoQ-, and PhoP-dependent manner. This RpoS accumulation was caused by another connector, IraM, expression of which was induced by the activation of the PhoQ/PhoP system, thus preventing RpoS degradation by trapping response regulator RssB. Acid resistance assays demonstrated that IraM also participated in the EvgS/EvgA-induced acid resistance. Therefore, we propose a model of a signal transduction cascade proceeding from EvgS/EvgA to PhoQ/PhoP and then to RssB (connected by SafA and IraM) and discuss its contribution to the acid resistance phenotype.

  16. The small noncoding DsrA RNA is an acid resistance regulator in Escherichia coli.

    PubMed

    Lease, Richard A; Smith, Dorie; McDonough, Kathleen; Belfort, Marlene

    2004-09-01

    DsrA RNA is a small (87-nucleotide) regulatory RNA of Escherichia coli that acts by RNA-RNA interactions to control translation and turnover of specific mRNAs. Two targets of DsrA regulation are RpoS, the stationary-phase and stress response sigma factor (sigmas), and H-NS, a histone-like nucleoid protein and global transcription repressor. Genes regulated globally by RpoS and H-NS include stress response proteins and virulence factors for pathogenic E. coli. Here, by using transcription profiling via DNA arrays, we have identified genes induced by DsrA. Steady-state levels of mRNAs from many genes increased with DsrA overproduction, including multiple acid resistance genes of E. coli. Quantitative primer extension analysis verified the induction of individual acid resistance genes in the hdeAB, gadAX, and gadBC operons. E. coli K-12 strains, as well as pathogenic E. coli O157:H7, exhibited compromised acid resistance in dsrA mutants. Conversely, overproduction of DsrA from a plasmid rendered the acid-sensitive dsrA mutant extremely acid resistant. Thus, DsrA RNA plays a regulatory role in acid resistance. Whether DsrA targets acid resistance genes directly by base pairing or indirectly via perturbation of RpoS and/or H-NS is not known, but in either event, our results suggest that DsrA RNA may enhance the virulence of pathogenic E. coli.

  17. Vitamin B12 and omega-3 fatty acids together regulate lipid metabolism in Wistar rats.

    PubMed

    Khaire, Amrita; Rathod, Richa; Kale, Anvita; Joshi, Sadhana

    2015-08-01

    Our recent study indicates that maternal vitamin B12 and omega-3 fatty acid status influence plasma and erythrocyte fatty acid profile in dams. The present study examines the effects of prenatal and postnatal vitamin B12 and omega-3 fatty acid status on lipid metabolism in the offspring. Pregnant dams were divided into five groups: Control; Vitamin B12 deficient (BD); Vitamin B12 supplemented (BS); Vitamin B12 deficient group supplemented with omega-3 fatty acids (BDO); Vitamin B12 supplemented group with omega-3 fatty acids (BSO). The offspring were continued on the same diets till 3 month of age. Vitamin B12 deficiency increased cholesterol levels (p<0.01) but reduced docosahexaenoic acid (DHA) (p<0.05), liver mRNA levels of acetyl CoA carboxylase-1 (ACC-1) (p<0.05) and carnitine palmitoyltransferase-1 (CPT-1) (p<0.01) in the offspring. Omega-3 fatty acid supplementation to this group normalized cholesterol but not mRNA levels of ACC-1 and CPT-1. Vitamin B12 supplementation normalized the levels cholesterol to that of control but increased plasma triglyceride (p<0.01) and reduced liver mRNA levels of adiponectin, ACC-1, and CPT-1 (p<0.01 for all). Supplementation of both vitamin B12 and omega-3 fatty acid normalized triglyceride and mRNA levels of all the above genes. Prenatal and postnatal vitamin B12 and omega-3 fatty acids together play a crucial role in regulating the genes involved in lipid metabolism in adult offspring.

  18. Direct block of the cystic fibrosis transmembrane conductance regulator Cl(-) channel by niflumic acid.

    PubMed

    Scott-Ward, T S; Li, H; Schmidt, A; Cai, Z; Sheppard, D N

    2004-01-01

    Niflumic acid is widely used to inhibit Ca(2+) -activated Cl(-) channels. However, the chemical structure of niflumic acid resembles that of diphenylamine-2-carboxylate, a drug that inhibits the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel. To investigate how niflumic acid inhibits CFTR Cl(-) channel, we studied recombinant wild-type human CFTR in excised inside-out membrane patches. When added to the intracellular solution, niflumic acid caused a concentration- and voltage-dependent decrease of CFTR Cl(-) current with half-maximal inhibitory concentration (K(i)) of 253 microM and Hill co-efficient of approximately 1, at -50 mV. Niflumic acid inhibition of single CFTR Cl(-) channels was characterized by a very fast, flickery block that decreased dramatically current amplitude without altering open-probability. Consistent with these data, spectral analysis of CFTR Cl(-) currents suggested that channel block by niflumic acid was described by the closed <--> open <--> blocked kinetic scheme with blocker on rate (k(on)) = 13.9 x 10(6) M(-1)s(-1), off rate (k(off))=3348 s(-1) and dissociation constant (K(d)) = 241 microM, at -50 mV. Based on these data, we tested the effects of niflumic acid on transepithelial Cl(-) secretion and cyst growth using type I MDCK epithelial cells. Niflumic acid (200 microM) inhibited cAMP-stimulated, bumetanide-sensitive short-circuit current by 55%. Moreover, the drug potently retarded cyst growth. We conclude that niflumic acid is an open-channel blocker of CFTR that inhibits Cl(-) permeation by plugging the channel pore. It or related agents might be of value in the development of new therapies for autosomal dominant polycystic kidney disease.

  19. Metabolic regulation of fatty acid esterification and effects of conjugated linoleic acid on glucose homeostasis in pig hepatocytes.

    PubMed

    Conde-Aguilera, J A; Lachica, M; Nieto, R; Fernández-Fígares, I

    2012-02-01

    Conjugated linoleic acids (CLAs) are geometric and positional isomers of linoleic acid (LA) that promote growth, alter glucose metabolism and decrease body fat in growing animals, although the mechanisms are poorly understood. A study was conducted to elucidate the effects of CLA on glucose metabolism, triglyceride (TG) synthesis and IGF-1 synthesis in primary culture of porcine hepatocytes. In addition, hormonal regulation of TG and IGF-1 synthesis was addressed. Hepatocytes were isolated from piglets (n = 5, 16.0 ± 1.98 kg average body weight) by collagenase perfusion and seeded into collagen-coated T-25 flasks. Hepatocytes were cultured in William's E containing dexamethasone (10-8 and 10-7 M), insulin (10 and 100 ng/ml), glucagon (0 and 100 ng/ml) and CLA (1 : 1 mixture of cis-9, trans-11 and trans-10, cis-12 CLA, 0.05 and 0.10 mM) or LA (0.05 and 0.10 mM). Addition of CLA decreased gluconeogenesis (P < 0.05), whereas glycogen synthesis and degradation, TG synthesis and IGF-1 synthesis were not affected compared with LA. Increased concentration of fatty acids in the media decreased IGF-1 production (P < 0.001) and glycogen synthesis (P < 0.01), and increased gluconeogenesis (P < 0.001) and TG synthesis (P < 0.001). IGF-1 synthesis increased (P < 0.001) and TG synthesis decreased (P < 0.001) as dexamethasone concentration in the media rose. High insulin/glucagon increased TG synthesis. These results indicate that TG synthesis in porcine hepatocytes is hormonally regulated so that dexamethasone decreases and insulin/glucagon increases it. In addition, CLA decreases hepatic glucose production through decreased gluconeogenesis.

  20. Regulation of intestinal IgA responses by dietary palmitic acid and its metabolism.

    PubMed

    Kunisawa, Jun; Hashimoto, Eri; Inoue, Asuka; Nagasawa, Risa; Suzuki, Yuji; Ishikawa, Izumi; Shikata, Shiori; Arita, Makoto; Aoki, Junken; Kiyono, Hiroshi

    2014-08-15

    Enhancement of intestinal IgA responses is a primary strategy in the development of oral vaccine. Dietary fatty acids are known to regulate host immune responses. In this study, we show that dietary palmitic acid (PA) and its metabolites enhance intestinal IgA responses. Intestinal IgA production was increased in mice maintained on a PA-enriched diet. These mice also showed increased intestinal IgA responses against orally immunized Ag, without any effect on serum Ab responses. We found that PA directly stimulates plasma cells to produce Ab. In addition, mice receiving a PA-enriched diet had increased numbers of IgA-producing plasma cells in the large intestine; this effect was abolished when serine palmitoyltransferase was inhibited. These findings suggest that dietary PA regulates intestinal IgA responses and has the potential to be a diet-derived mucosal adjuvant.

  1. Phospholipase D1-regulated autophagy supplies free fatty acids to counter nutrient stress in cancer cells

    PubMed Central

    Cai, Ming; He, Jingquan; Xiong, Jian; Tay, Li Wei Rachel; Wang, Ziqing; Rog, Colin; Wang, Jingshu; Xie, Yizhao; Wang, Guobin; Banno, Yoshiko; Li, Feng; Zhu, Michael; Du, Guangwei

    2016-01-01

    Cancer cells utilize flexible metabolic programs to maintain viability and proliferation under stress conditions including nutrient deprivation. Here we report that phospholipase D1 (PLD1) participates in the regulation of metabolic plasticity in cancer cells. PLD1 activity is required for cancer cell survival during prolonged glucose deprivation. Blocking PLD1 sensitizes cancer cells to glycolysis inhibition by 2-deoxy-D-glucose (2-DG) and results in decreased autophagic flux, enlarged lysosomes, and increased lysosomal pH. Mechanistically, PLD1-regulated autophagy hydrolyzes bulk membrane phospholipids to supply fatty acids (FAs) for oxidation in mitochondria. In low glucose cultures, the blockade of fatty acid oxidation (FAO) by PLD1 inhibition suppresses adenosine triphosphate (ATP) production and increases reactive oxygen species (ROS), leading to cancer cell death. In summary, our findings reveal a novel role of PLD1 in sustaining cancer cell survival during metabolic stress, and suggest PLD1 as a potential target for anticancer metabolism therapy. PMID:27809301

  2. Antiepileptic potential of matrine via regulation the levels of gamma-aminobutyric acid and glutamic acid in the brain.

    PubMed

    Xiang, Jun; Jiang, Yugang

    2013-12-05

    Our present study aimed to determine the antiepileptic activity of matrine, and explore the possible molecular mechanism. To evaluate the antiepileptic activity of matrine, seizures in mice induced by PTZ and MES were established, then the pentobarbital sodium-induced anaesthetizing time and locomotor activity tests in mice were also carried out. For the molecular mechanism investigations, contents of aspartic acid (Asp), gamma-aminobutyric acid (GABA), glutamic acid (Glu), glycine (Gly) in seizures mice were determined; then, the chronic seizures rats induced by PTZ were prepared, and western blotting was used to determine the expressions of GAD 65, GABAA and GABAB in the brains. In the results, matrine showed significant antiepileptic effects on seizures mice induced by MES and PTZ. Moreover, the pentobarbital sodium-induced anaesthetizing time and locomotor activity tests were also demonstrated that matrine had obvious antiepileptic effects. Additionally, our results revealed that after treatment with matrine, contents of GABA can be elevated, and the contents of Glu were obviously decreased. Furthermore, western blotting revealed that the mechanism regarding the antiepileptic effect of may be related to the up-regulations of GAD 65 and GABAA in the brain. Collectively, we suggested that matrine can be developed as an effective antiseptic drug.

  3. Hormonal Regulation and Expression Profiles of Wheat Genes Involved during Phytic Acid Biosynthesis Pathway

    PubMed Central

    Aggarwal, Sipla; Shukla, Vishnu; Bhati, Kaushal Kumar; Kaur, Mandeep; Sharma, Shivani; Singh, Anuradha; Mantri, Shrikant; Pandey, Ajay Kumar

    2015-01-01

    Phytic acid (PA) biosynthesis pathway genes were reported from multiple crop species. PA accumulation was enhanced during grain filling and at that time, hormones like Abscisic acid (ABA) and Gibberellic acid (GA3) interplay to control the process of seed development. Regulation of wheat PA pathway genes has not yet been reported in seeds. In an attempt to find the clues for the regulation by hormones, the promoter region of wheat PA pathway genes was analyzed for the presence of cis-elements. Multiple cis-elements of those known to be involved for ABA, GA3, salicylic acid (SA), and cAMP sensing were identified in the promoters of PA pathway genes. Eight genes (TaIMP, TaITPK1-4, TaPLC1, TaIPK2 and TaIPK1) involved in the wheat PA biosynthesis pathway were selected for the expression studies. The temporal expression response was studied in seeds treated with ABA and GA3 using quantitative real time PCR. Our results suggested that exogenous application of ABA induces few PA pathway genes in wheat grains. Comparison of expression profiles for PA pathway for GA3 and ABA suggested the antagonistic regulation of certain genes. Additionally, to reveal stress responses of wheat PA pathway genes, expression was also studied in the presence of SA and cAMP. Results suggested SA specific differential expression of few genes, whereas, overall repression of genes was observed in cAMP treated samples. This study is an effort to understand the regulation of PA biosynthesis genes in wheat. PMID:27135330

  4. Operational testing of valve regulated lead acid batteries in commercial aircraft

    SciTech Connect

    Timmons, J.B.; Koss, E.F.

    1997-12-01

    Valve regulated lead acid (VRLA) batteries provide electrical performance that is virtually identical to sintered plate nickel-cadmium battery systems. In addition, the VRLA batteries offer the user a no maintenance battery and other enhanced features that make this a very desirable battery for aircraft applications. In field trials, where VRLA batteries were substituted for nickel-cadmium batteries, the VRLA provided the user with a high reliability turbine engine starting battery under a wide variety of climatic conditions.

  5. Hormonal Regulation and Expression Profiles of Wheat Genes Involved during Phytic Acid Biosynthesis Pathway.

    PubMed

    Aggarwal, Sipla; Shukla, Vishnu; Bhati, Kaushal Kumar; Kaur, Mandeep; Sharma, Shivani; Singh, Anuradha; Mantri, Shrikant; Pandey, Ajay Kumar

    2015-06-11

    Phytic acid (PA) biosynthesis pathway genes were reported from multiple crop species. PA accumulation was enhanced during grain filling and at that time, hormones like Abscisic acid (ABA) and Gibberellic acid (GA₃) interplay to control the process of seed development. Regulation of wheat PA pathway genes has not yet been reported in seeds. In an attempt to find the clues for the regulation by hormones, the promoter region of wheat PA pathway genes was analyzed for the presence of cis-elements. Multiple cis-elements of those known to be involved for ABA, GA₃, salicylic acid (SA), and cAMP sensing were identified in the promoters of PA pathway genes. Eight genes (TaIMP, TaITPK1-4, TaPLC1, TaIPK2 and TaIPK1) involved in the wheat PA biosynthesis pathway were selected for the expression studies. The temporal expression response was studied in seeds treated with ABA and GA₃ using quantitative real time PCR. Our results suggested that exogenous application of ABA induces few PA pathway genes in wheat grains. Comparison of expression profiles for PA pathway for GA₃ and ABA suggested the antagonistic regulation of certain genes. Additionally, to reveal stress responses of wheat PA pathway genes, expression was also studied in the presence of SA and cAMP. Results suggested SA specific differential expression of few genes, whereas, overall repression of genes was observed in cAMP treated samples. This study is an effort to understand the regulation of PA biosynthesis genes in wheat.

  6. Prohibitin/annexin 2 interaction regulates fatty acid transport in adipose tissue

    PubMed Central

    Salameh, Ahmad; Daquinag, Alexes C.; Staquicini, Daniela I.; An, Zhiqiang; Pasqualini, Renata; Kolonin, Mikhail G.

    2016-01-01

    We have previously identified prohibitin (PHB) and annexin A2 (ANX2) as proteins interacting on the surface of vascular endothelial cells in white adipose tissue (WAT) of humans and mice. Here, we demonstrate that ANX2 and PHB also interact in adipocytes. Mice lacking ANX2 have normal WAT vascularization, adipogenesis, and glucose metabolism but display WAT hypotrophy due to reduced fatty acid uptake by WAT endothelium and adipocytes. By using cell culture systems in which ANX2/PHB binding is disrupted either genetically or through treatment with a blocking peptide, we show that fatty acid transport efficiency relies on this protein complex. We also provide evidence that the interaction between ANX2 and PHB mediates fatty acid transport from the endothelium into adipocytes. Moreover, we demonstrate that ANX2 and PHB form a complex with the fatty acid transporter CD36. Finally, we show that the colocalization of PHB and CD36 on adipocyte surface is induced by extracellular fatty acids. Together, our results suggest that an unrecognized biochemical interaction between ANX2 and PHB regulates CD36-mediated fatty acid transport in WAT, thus revealing a new potential pathway for intervention in metabolic diseases. PMID:27468426

  7. A high-fat diet regulates gastrin and acid secretion through primary cilia.

    PubMed

    Saqui-Salces, Milena; Dowdle, William E; Reiter, Jeremy F; Merchant, Juanita L

    2012-08-01

    The role of primary cilia in the gastrointestinal tract has not been examined. Here we report the presence of primary cilia on gastric endocrine cells producing gastrin, ghrelin, and somatostatin (Sst), hormones regulated by food intake. During eating, cilia in the gastric antrum decreased, whereas gastric acid and circulating gastrin increased. Mice fed high-fat chow showed a delayed decrease in antral cilia, increased plasma gastrin, and gastric acidity. Mice fed high-fat chow for 3 wk showed lower cilia numbers and acid but higher gastrin levels than mice fed a standard diet, suggesting that fat affects gastric physiology. Ex vivo experiments showed that cilia in the corpus responded to acid and distension, whereas cilia in the antrum responded to food. To analyze the role of gastric cilia, we conditionally deleted the intraflagellar transport protein Ift88 (Ift88(-/fl)). In fed Ift88(-/fl) mice, gastrin levels were higher, and gastric acidity was lower. Moreover, gastrin and Sst gene expression did not change in response to food as in controls. At 8 mo, Ift88(-/fl) mice developed foveolar hyperplasia, hypergastrinemia, and hypochlorhydria associated with endocrine dysfunction. Our results show that components of food (fat) are sensed by antral cilia on endocrine cells, which modulates gastrin secretion and gastric acidity.

  8. Pyruvate kinase is a dosage-dependent regulator of cellular amino acid homeostasis

    PubMed Central

    Grüning, Nana-Maria; Feichtinger, René; Krüger, Antje; Wamelink, Mirjam; Lehrach, Hans; Tate, Stephen; Neureiter, Daniel; Kofler, Barbara

    2012-01-01

    The glycolytic enzyme pyruvate kinase (PK) is required for cancer development, and has been implicated in the metabolic transition from oxidative to fermentative metabolism, the Warburg effect. However, the global metabolic response that follows changes in PK activity is not yet fully understood. Using shotgun proteomics, we identified 31 yeast proteins that were regulated in a PK-dependent manner. Selective reaction monitoring confirmed that their expression was dependent on PK isoform, level and activity. Most of the PK targets were amino acid metabolizing enzymes or factors of protein translation, indicating that PK plays a global regulatory role in biosynthethic amino acid metabolism. Indeed, we found strongly altered amino acid profiles when PK levels were changed. Low PK levels increased the cellular glutamine and glutamate concentrations, but decreased the levels of seven amino acids including serine and histidine. To test for evolutionary conservation of this PK function, we quantified orthologues of the identified PK targets in thyroid follicular adenoma, a tumor characterized by high PK levels and low respiratory activity. Aminopeptidase AAP-1 and serine hydroxymethyltransferase SHMT1 both showed PKM2- concentration dependence, and were upregulated in the tumor. Thus, PK expression levels and activity were important for maintaining cellular amino acid homeostasis. Mediating between energy production, ROS clearance and amino acid biosynthesis, PK thus plays a central regulatory role in the metabolism of proliferating cells. PMID:23154538

  9. The Secreted Enzyme PM20D1 Regulates Lipidated Amino Acid Uncouplers of Mitochondria.

    PubMed

    Long, Jonathan Z; Svensson, Katrin J; Bateman, Leslie A; Lin, Hua; Kamenecka, Theodore; Lokurkar, Isha A; Lou, Jesse; Rao, Rajesh R; Chang, Mi Ra; Jedrychowski, Mark P; Paulo, Joao A; Gygi, Steven P; Griffin, Patrick R; Nomura, Daniel K; Spiegelman, Bruce M

    2016-07-14

    Brown and beige adipocytes are specialized cells that express uncoupling protein 1 (UCP1) and dissipate chemical energy as heat. These cells likely possess alternative UCP1-independent thermogenic mechanisms. Here, we identify a secreted enzyme, peptidase M20 domain containing 1 (PM20D1), that is enriched in UCP1(+) versus UCP1(-) adipocytes. We demonstrate that PM20D1 is a bidirectional enzyme in vitro, catalyzing both the condensation of fatty acids and amino acids to generate N-acyl amino acids and also the reverse hydrolytic reaction. N-acyl amino acids directly bind mitochondria and function as endogenous uncouplers of UCP1-independent respiration. Mice with increased circulating PM20D1 have augmented respiration and increased N-acyl amino acids in blood. Lastly, administration of N-acyl amino acids to mice improves glucose homeostasis and increases energy expenditure. These data identify an enzymatic node and a family of metabolites that regulate energy homeostasis. This pathway might be useful for treating obesity and associated disorders.

  10. Low-maintenance, valve-regulated, lead/acid batteries in utility applications

    NASA Astrophysics Data System (ADS)

    Cook, G. M.; Spindler, W. C.

    Electric power utility companies have various needs for lead/acid batteries, and also are beginning to promote customer-side-of-the meter applications for mutual benefits. Increasing use of lead/acid batteries in the future will depend heavily on improving performance and reliability of sealed, recombination designs, and on their versatility for many applications. Classifying various utility uses could be by cycling requirements, depth-of-discharge, power or energy (ratio of watts to hours), or by site (utility or customer). Deep-cycling examples are energy storage, peak-shaving and electric vehicles. Shallow-cycling examples are frequency regulation and reactive power control. Infrequent discharge examples are stationary service and spinning reserve. (Float service for telecommunications and uninterruptible power sources (UPS) applications are not addressed.) Some present and planned installations of valve-regulated lead/acid batteries are surveyed. Performance characteristics will be discussed, including recent results of testing both gel and absorptive glass mat (AGM) types of deep-cycling batteries. Recommendations for future research and development of valve-regulated cell technology are outlined, based on a recent conference organized by the United States Department of Energy (USDOE) and the Electric Power Research Institute (EPRI).

  11. Role for hepatic CEACAM1 in regulating fatty acid metabolism along the adipocyte-hepatocyte axis.

    PubMed

    Russo, Lucia; Ghadieh, Hilda E; Ghanem, Simona S; Al-Share, Qusai Y; Smiley, Zachary N; Gatto-Weis, Cara; Esakov, Emily L; McInerney, Marcia F; Heinrich, Garrett; Tong, Xin; Yin, Lei; Najjar, Sonia M

    2016-12-01

    Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) regulates insulin sensitivity by promoting hepatic insulin clearance and mediating suppression of fatty acid synthase activity. Feeding C57BL/6J male mice with a high-fat (HF) diet for 3-4 weeks triggered a >60% decrease in hepatic CEACAM1 levels to subsequently impair insulin clearance and cause systemic insulin resistance and hepatic steatosis. This study aimed at investigating whether lipolysis drives reduction in hepatic CEACAM1 and whether this constitutes a key mechanism leading to diet-induced metabolic abnormalities. Blocking lipolysis with a daily intraperitoneal injection of nicotinic acid in the last two days of a 30-day HF feeding regimen demonstrated that white adipose tissue (WAT)-derived fatty acids repressed hepatic CEACAM1-dependent regulation of insulin and lipid metabolism in 3-month-old male C57BL/6J mice. Adenoviral-mediated CEACAM1 redelivery countered the adverse metabolic effect of the HF diet on insulin resistance, hepatic steatosis, visceral obesity, and energy expenditure. It also reversed the effect of HF diet on inflammation and fibrosis in WAT and liver. This assigns a causative role for lipolysis-driven decrease in hepatic CEACAM1 level and its regulation of insulin and lipid metabolism in sustaining systemic insulin resistance, hepatic steatosis, and other abnormalities associated with excessive energy supply. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

  12. Tumor cell invasion of basement membrane in vitro is regulated by amino acids.

    PubMed

    Singh, R K; Rinehart, C A; Kim, J P; Tolleson-Rinehart, S; Lawing, L F; Kaufman, D G; Siegal, G P

    1996-01-01

    Because most cancer deaths result from disseminated disease, understanding the regulation of tumor invasion and metastasis is a central theme in tumor cell biology. Interactions between extracellular matrices (ECM) and cellular microenvironment play a crucial role in this process. We have tested selected amino acids and polyamines for their ability to regulate RL95-2 cell invasion through both intact human amniotic basement membrane and a novel human ECM (Amgel). Three major systems for neutral amino acid transport, systems L, A, and ASC, are operational in these neoplastic cells. Amino acids entering the cell via transport system A or N, i.e., (methyl amino)-isobutyrate (MeAIB) or Asn, markedly enhanced invasiveness of these human adenocarcinoma cells as measured by a standard 72-hr amnion or Amgel invasion assay. Addition of 2-amino-2-norborane carboxylic acid (BCH; 1 mM), a model substrate of the L transport system, caused a significant decrease in invasive activity when tested in the Amgel assay. Interestingly, Val lowers steady-state levels of MeAIB uptake and blocks the increase in cell invasion elicited by MeAIB. At the same time, these amino acids do not influence cell proliferation activity. Neither the charged amino acid Lys or Asp (not transported by A/N/L systems) nor the polyamines putrescine, spermidine, or spermine modulate invasiveness under similar experimental conditions. Moreover, the observed time-dependent stimulation of system A activity (cellular influx of MeAIB) by substrate depletion is prevented by the addition of actinomycin D (5 microM) or cycloheximide (100 microM), suggesting the involvement of de novo RNA and protein synthesis events in these processes. MeAIB treatment of tumor cells selectively increased the activities of key invasion-associated type IV collagenases/gelatinases. These results indicate that in the absence of defined regulators (growth factors or hormones), certain amino acids may contribute to the epigenetic control

  13. Ca2+/H+ exchange by acidic organelles regulates cell migration in vivo

    PubMed Central

    Melchionda, Manuela; Pittman, Jon K.

    2016-01-01

    Increasing evidence implicates Ca2+ in the control of cell migration. However, the underlying mechanisms are incompletely understood. Acidic Ca2+ stores are fast emerging as signaling centers. But how Ca2+ is taken up by these organelles in metazoans and the physiological relevance for migration is unclear. Here, we identify a vertebrate Ca2+/H+ exchanger (CAX) as part of a widespread family of homologues in animals. CAX is expressed in neural crest cells and required for their migration in vivo. It localizes to acidic organelles, tempers evoked Ca2+ signals, and regulates cell-matrix adhesion during migration. Our data provide new molecular insight into how Ca2+ is handled by acidic organelles and link this to migration, thereby underscoring the role of noncanonical Ca2+ stores in the control of Ca2+-dependent function. PMID:27002171

  14. Ca2+/H+ exchange by acidic organelles regulates cell migration in vivo.

    PubMed

    Melchionda, Manuela; Pittman, Jon K; Mayor, Roberto; Patel, Sandip

    2016-03-28

    Increasing evidence implicates Ca(2+) in the control of cell migration. However, the underlying mechanisms are incompletely understood. Acidic Ca(2+) stores are fast emerging as signaling centers. But how Ca(2+) is taken up by these organelles in metazoans and the physiological relevance for migration is unclear. Here, we identify a vertebrate Ca(2+)/H(+)exchanger (CAX) as part of a widespread family of homologues in animals. CAX is expressed in neural crest cells and required for their migration in vivo. It localizes to acidic organelles, tempers evoked Ca(2+) signals, and regulates cell-matrix adhesion during migration. Our data provide new molecular insight into how Ca(2+) is handled by acidic organelles and link this to migration, thereby underscoring the role of noncanonical Ca(2+) stores in the control of Ca(2+)-dependent function. © 2016 Melchionda et al.

  15. Hepatocyte nuclear factor 4α regulation of bile acid and drug metabolism

    PubMed Central

    Chiang, John YL

    2013-01-01

    The hepatocyte nuclear factor 4α (HNF4α) is a liver-enriched nuclear receptor that plays a critical role in early morphogenesis, fetal liver development, liver differentiation and metabolism. Human HNF4α gene mutations cause maturity on-set diabetes of the young type 1, an autosomal dominant non-insulin-dependent diabetes mellitus. HNF4α is an orphan nuclear receptor because of which the endogenous ligand has not been firmly identified. The trans-activating activity of HNF4α is enhanced by interacting with co-activators and inhibited by corepressors. Recent studies have revealed that HNF4α plays a central role in regulation of bile acid metabolism in the liver. Bile acids are required for biliary excretion of cholesterol and metabolites, and intestinal absorption of fat, nutrients, drug and xenobiotics for transport and distribution to liver and other tissues. Bile acids are signaling molecules that activate nuclear receptors to control lipids and drug metabolism in the liver and intestine. Therefore, HNF4α plays a central role in coordinated regulation of bile acid and xenobiotics metabolism. Drugs that specifically activate HNF4α could be developed for treating metabolic diseases such as diabetes, dyslipidemia and cholestasis, as well as drug metabolism and detoxification. PMID:19239393

  16. Regulation by organic acids of polysaccharide-mediated microbe-plant interactions.

    PubMed

    Nakata, K; Kobayashi, T; Takiguchi, Y; Yamaguchi, T

    2000-10-01

    A polysaccharide flocculant of Klebsiella pneumoniae H12 has been suggested to mediate microbe-plant interactions with the aid of Ca2+ [K. Nakata et al., Biosci. Biotechnol. Biochem., 64, 459-465, 2000]. Here, two-way regulation of polysaccharide-mediated interactions between K. pneumoniae and Raphanus sativus was studied using organic acids. Namely, 10 mM equivalents of organic acids promoted production of the polysaccharide by the bacterium, but inhibited flocculation of bacterial cells by the polysaccharide. These phenomena were counterbalanced by equi-molar equivalents of Ca2+, suggesting competition for Ca2+ between the carboxylic residues of the polysaccharide and those of the aliphatic acids. By electron microscopy observations, bacterial cell aggregates were sparsely distributed over the main roots and root hairs, had various sizes, and seemed to tightly adhere to root tissues. Their shapes seemed to be distorted and abundant in cavities. In brief, these microscopical observations may be explained by a two-way regulation system of bacterial adhesion to a plant by organic acids.

  17. Regulation of selenoprotein mRNA expression by hormones and retinoic acid in bovine mammary cells.

    PubMed

    Bruzelius, Katharina; Sundler, Roger; Pagmantidis, Vasileios; Akesson, Björn

    2010-10-01

    Selenium is essential for maintaining many body functions through the actions of selenoproteins. To find factors regulating selenoprotein biosynthesis in the bovine mammary cell line MAC-T, the effects of supplementation with selenite and also with retinoic acid, insulin, hydrocortisone and prolactin on the mRNA expression of a number of selenoproteins were investigated. It was found that MAC-T cells express glutathione peroxidase (GPx) 1 and 4, thioredoxin reductase 1 and selenoprotein P, but not GPx 3, which is interesting considering that GPx 3 is one of the only few selenoproteins detected in milk so far. Addition of selenite to the cell culture resulted in a large increase in GPx 1 expression and an increase in selenoprotein P expression, which is similar to the findings made in other systems investigated. Increased mRNA levels of GPx 1 were also observed in cells treated with insulin and hydrocortisone or with retinoic acid. The expression of thioredoxin reductase 1 was increased in cells treated with retinoic acid, whereas that of selenoprotein P was decreased in cells exposed to insulin. The results indicate that several hormones, selenium, and retinoic acid regulate the biosynthesis of various selenoproteins differently in the bovine mammary cell. The possible implications of the findings for processes related to milk formation and mammary carcinogenesis will need additional investigation. Further study of the detailed mechanisms involved is also necessary. Copyright © 2010. Published by Elsevier GmbH.

  18. Pathological regulation of arachidonic acid release in cystic fibrosis: the putative basic defect.

    PubMed Central

    Carlstedt-Duke, J; Brönnegård, M; Strandvik, B

    1986-01-01

    The regulation of arachidonic acid release from membrane phospholipids was investigated in lymphocytes from patients with cystic fibrosis as well as control patients. No effect of either dexamethasone or fetal calf serum was seen on arachidonic acid release from cystic fibrosis lymphocytes, in contrast to control lymphocytes. In the latter cells, arachidonic acid release was inhibited by dexamethasone, fetal calf serum, or both. There were no differences in glucocorticoid receptor in lymphocytes from the two groups with regard to Kd and number of binding sites per cell. Furthermore, dexamethasone inhibited the incorporation of thymidine into lymphocytes from either group, indicating a normal functional glucocorticoid receptor. The defective regulation of arachidonic acid, resulting in an increased turnover, can explain many of the findings in cystic fibrosis, and we hypothesize that it is the basic defect causing the disease. The defect occurs at a level after the glucocorticoid receptor, which is functionally normal, and involves either the glucocorticoid-dependent phospholipase-inhibitory protein lipomodulin (lipocortin) or phospholipase A2. PMID:3097647

  19. Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

    PubMed Central

    Ljungdahl, Per O.; Daignan-Fornier, Bertrand

    2012-01-01

    Ever since the beginning of biochemical analysis, yeast has been a pioneering model for studying the regulation of eukaryotic metabolism. During the last three decades, the combination of powerful yeast genetics and genome-wide approaches has led to a more integrated view of metabolic regulation. Multiple layers of regulation, from suprapathway control to individual gene responses, have been discovered. Constitutive and dedicated systems that are critical in sensing of the intra- and extracellular environment have been identified, and there is a growing awareness of their involvement in the highly regulated intracellular compartmentalization of proteins and metabolites. This review focuses on recent developments in the field of amino acid, nucleotide, and phosphate metabolism and provides illustrative examples of how yeast cells combine a variety of mechanisms to achieve coordinated regulation of multiple metabolic pathways. Importantly, common schemes have emerged, which reveal mechanisms conserved among various pathways, such as those involved in metabolite sensing and transcriptional regulation by noncoding RNAs or by metabolic intermediates. Thanks to the remarkable sophistication offered by the yeast experimental system, a picture of the intimate connections between the metabolomic and the transcriptome is becoming clear. PMID:22419079

  20. Na+-K+-2Cl- cotransporters and Cl- channels regulate citric acid cough in guinea pigs.

    PubMed

    Mazzone, Stuart B; McGovern, Alice E

    2006-08-01

    Loop diuretics have been shown to inhibit cough and other airway defensive reflexes via poorly defined mechanisms. We test the hypothesis that the furosemide-sensitive Na+-K+-2Cl- cotransporter (NKCC1) is expressed by sensory nerve fibers innervating the airways where it plays an important role in regulating sensory neural activity. NKCC1 immunoreactivity was present on the cell membranes of most nodose and jugular ganglia neurons projecting to the trachea, and it was present on the peripheral terminals of putative mechanosensory nerve fibers in the airways. In urethane-anesthetized, spontaneously breathing guinea pigs, bolus application of citric acid (1 mM to 2 M) to an isolated and perfused segment of the tracheal mucosa evoked coughing and respiratory slowing. Removal of Cl- from the tracheal perfusate evoked spontaneous coughing and significantly potentiated cough and respiratory slowing reflexes evoked by citric acid. The NKCC1 inhibitor furosemide (10-100 microM) significantly reduced both the number of coughs evoked by citric acid and the degree of acid-evoked respiratory slowing (P < 0.05). Localized tracheal pretreatment with the Cl- channel inhibitors DIDS or niflumic acid (100 microM) also significantly reduced cough, whereas the GABAA receptor agonist muscimol potentiated acid-evoked responses. These data suggest that vagal sensory neurons may accumulate Cl- due to the expression of the furosemide-sensitive Cl- transporter, NKCC1. Efflux of intracellular Cl-, in part through calcium-activated Cl- channels, may play an important role in regulating airway afferent neuron activity.

  1. Chemical regulation of abscisic acid catabolism in plants by cytochrome P450 inhibitors.

    PubMed

    Kitahata, Nobutaka; Saito, Shigeki; Miyazawa, Yutaka; Umezawa, Taishi; Shimada, Yukihisa; Min, Yong Ki; Mizutani, Masaharu; Hirai, Nobuhiro; Shinozaki, Kazuo; Yoshida, Shigeo; Asami, Tadao

    2005-07-15

    Plant hormone abscisic acid (ABA) is an important factor for conferring drought stress resistance on plants. Therefore, small molecules that regulate ABA levels in plants can be useful both for investigating functions of ABA and for developing new plant growth regulators. Abscisic acid (ABA) catabolism in plants is primarily regulated by ABA 8'-hydroxylase, which is a cytochrome P450 (P450). We tested known P450 inhibitors containing a triazole group and found that uniconazole-P inhibited ABA catabolism in cultured tobacco Bright Yellow-2 cells. In a structure-activity study of uniconazole, we found a more effective ABA catabolic inhibitor (diniconazole) than uniconazole-P. Diniconazole, a fungicide, acted as a potent competitive inhibitor of recombinant Arabidopsis ABA 8'-hydroxylase, CYP707A3, in an in vitro assay. Diniconazole-treated plants retained a higher ABA content and higher transcription levels of ABA response genes during rehydration than did untreated plants and were more drought stress tolerant than untreated plants. These results strongly suggest that ABA catabolic inhibitors that target ABA 8'-hydroxylase can regulate the ABA content of plants and conferred drought stress resistance on plants. The optical resolution of diniconazole revealed that the S-form isomer, which is a weak fungicidal isomer, was more active as an ABA catabolic inhibitor than was the R-form isomer.

  2. Isp7 is a novel regulator of amino acid uptake in the TOR signaling pathway.

    PubMed

    Laor, Dana; Cohen, Adiel; Pasmanik-Chor, Metsada; Oron-Karni, Varda; Kupiec, Martin; Weisman, Ronit

    2014-03-01

    TOR proteins reside in two distinct complexes, TOR complexes 1 and 2 (TORC1 and TORC2), that are central for the regulation of cellular growth, proliferation, and survival. TOR is also the target for the immunosuppressive and anticancer drug rapamycin. In Schizosaccharomyces pombe, disruption of the TSC complex, mutations in which can lead to the tuberous sclerosis syndrome in humans, results in a rapamycin-sensitive phenotype under poor nitrogen conditions. We show here that the sensitivity to rapamycin is mediated via inhibition of TORC1 and suppressed by overexpression of isp7(+), a member of the family of 2-oxoglutarate-Fe(II)-dependent oxygenase genes. The transcript level of isp7(+) is negatively regulated by TORC1 but positively regulated by TORC2. Yet we find extensive similarity between the transcriptome of cells disrupted for isp7(+) and cells mutated in the catalytic subunit of TORC1. Moreover, Isp7 regulates amino acid permease expression in a fashion similar to that of TORC1 and opposite that of TORC2. Overexpression of isp7(+) induces TORC1-dependent phosphorylation of ribosomal protein Rps6 while inhibiting TORC2-dependent phosphorylation and activation of the AGC-like kinase Gad8. Taken together, our findings suggest a central role for Isp7 in amino acid homeostasis and the presence of isp7(+)-dependent regulatory loops that affect both TORC1 and TORC2.

  3. Arginine methylation of HSP70 regulates retinoid acid-mediated RARβ2 gene activation

    PubMed Central

    Gao, Wei-wei; Xiao, Rong-quan; Peng, Bing-ling; Xu, Huan-teng; Shen, Hai-feng; Huang, Ming-feng; Shi, Tao-tao; Yi, Jia; Zhang, Wen-juan; Wu, Xiao-nan; Gao, Xiang; Lin, Xiang-zhi; Dorrestein, Pieter C.; Rosenfeld, Michael G.; Liu, Wen

    2015-01-01

    Although “histone” methyltransferases and demethylases are well established to regulate transcriptional programs and to use nonhistone proteins as substrates, their possible roles in regulation of heat-shock proteins in the nucleus have not been investigated. Here, we report that a highly conserved arginine residue, R469, in HSP70 (heat-shock protein of 70 kDa) proteins, an evolutionarily conserved protein family of ATP-dependent molecular chaperone, was monomethylated (me1), at least partially, by coactivator-associated arginine methyltransferase 1/protein arginine methyltransferase 4 (CARM1/PRMT4) and demethylated by jumonji-domain–containing 6 (JMJD6), both in vitro and in cultured cells. Functional studies revealed that HSP70 could directly regulate retinoid acid (RA)-induced retinoid acid receptor β2 (RARβ2) gene transcription through its binding to chromatin, with R469me1 being essential in this process. HSP70’s function in gene transcriptional regulation appears to be distinct from its protein chaperon activity. R469me1 was shown to mediate the interaction between HSP70 and TFIIH, which involves in RNA polymerase II phosphorylation and thus transcriptional initiation. Our findings expand the repertoire of nonhistone substrates targeted by PRMT4 and JMJD6, and reveal a new function of HSP70 proteins in gene transcription at the chromatin level aside from its classic role in protein folding and quality control. PMID:26080448

  4. Auxin Controls Arabidopsis Adventitious Root Initiation by Regulating Jasmonic Acid Homeostasis[W

    PubMed Central

    Gutierrez, Laurent; Mongelard, Gaëlle; Floková, Kristýna; Păcurar, Daniel I.; Novák, Ondřej; Staswick, Paul; Kowalczyk, Mariusz; Păcurar, Monica; Demailly, Hervé; Geiss, Gaia; Bellini, Catherine

    2012-01-01

    Vegetative shoot-based propagation of plants, including mass propagation of elite genotypes, is dependent on the development of shoot-borne roots, which are also called adventitious roots. Multiple endogenous and environmental factors control the complex process of adventitious rooting. In the past few years, we have shown that the auxin response factors ARF6 and ARF8, targets of the microRNA miR167, are positive regulators of adventitious rooting, whereas ARF17, a target of miR160, is a negative regulator. We showed that these genes have overlapping expression profiles during adventitious rooting and that they regulate each other’s expression at the transcriptional and posttranscriptional levels by modulating the homeostasis of miR160 and miR167. We demonstrate here that this complex network of transcription factors regulates the expression of three auxin-inducible Gretchen Hagen3 (GH3) genes, GH3.3, GH3.5, and GH3.6, encoding acyl-acid-amido synthetases. We show that these three GH3 genes are required for fine-tuning adventitious root initiation in the Arabidopsis thaliana hypocotyl, and we demonstrate that they act by modulating jasmonic acid homeostasis. We propose a model in which adventitious rooting is an adaptive developmental response involving crosstalk between the auxin and jasmonate regulatory pathways. PMID:22730403

  5. Bile acids in regulation of inflammation and immunity: friend or foe?

    PubMed

    Zhu, Ci; Fuchs, Claudia D; Halilbasic, Emina; Trauner, Michael

    2016-01-01

    Apart from their pivotal role in dietary lipid absorption and cholesterol homeostasis, bile acids (BAs) are increasingly recognised as important signalling molecules in the regulation of systemic endocrine functions. As such BAs are natural ligands for several nuclear hormone receptors and G-protein-coupled receptors. Through activating various signalling pathways, BAs not only regulate their own synthesis, enterohepatic recirculation and metabolism, but also immune homeostasis. This makes BAs attractive therapeutic agents for managing metabolic and inflammatory liver disorders. Recent experimental and clinical evidence indicates that BAs exert beneficial effects in cholestatic and metabolically driven inflammatory diseases. This review elucidates how different BAs function as pathogenetic factors and potential therapeutic agents for inflammation-driven liver diseases, focusing on their role in regulation of inflammation and immunity.

  6. Dietary gut microbial metabolites, short-chain fatty acids, and host metabolic regulation.

    PubMed

    Kasubuchi, Mayu; Hasegawa, Sae; Hiramatsu, Takero; Ichimura, Atsuhiko; Kimura, Ikuo

    2015-04-14

    During feeding, the gut microbiota contributes to the host energy acquisition and metabolic regulation thereby influencing the development of metabolic disorders such as obesity and diabetes. Short-chain fatty acids (SCFAs) such as acetate, butyrate, and propionate, which are produced by gut microbial fermentation of dietary fiber, are recognized as essential host energy sources and act as signal transduction molecules via G-protein coupled receptors (FFAR2, FFAR3, OLFR78, GPR109A) and as epigenetic regulators of gene expression by the inhibition of histone deacetylase (HDAC). Recent evidence suggests that dietary fiber and the gut microbial-derived SCFAs exert multiple beneficial effects on the host energy metabolism not only by improving the intestinal environment, but also by directly affecting various host peripheral tissues. In this review, we summarize the roles of gut microbial SCFAs in the host energy regulation and present an overview of the current understanding of its physiological functions.

  7. The secretion of organic acids is also regulated by factors other than aluminum.

    PubMed

    Ding, Haiyan; Wen, Danni; Fu, Zhengwei; Qian, Haifeng

    2014-02-01

    As a result of natural processes and human activities, aluminum (Al) toxicity is recognized as a major limiting factor for plant productivity, and the secretion of organic acids facilitated by channel proteins is one of the most important Al resistance mechanisms in plants. The objective of this study was to evaluate the effects of several types of stress, including herbicide (imazethapyr (IM) and diclofop-methyl (DM)), heavy metal (Al and Cu), salt stress (NaCl), and proton stress (HCl), on the release of organic acids in rice. The results showed that 0.05 mg/L IM, 0.1 mg/L DM, 4680 mg/L NaCl, 0.5 mg/L CuSO4, and 18 mg/L AlCl3 significantly inhibited rice root elongation and the root fresh weight. In contrast, no significant inhibitory effects on rice growth were found with HCl (pH = 4.5). Similar to the effect of AlCl3 on organic acid induction, treatment with IM, DM, NaCl, and CuSO4 also induced the synthesis of endogenous citric acid and oxalic acid but decreased endogenous malic acid synthesis in the seedlings, though only citric acid was released into the environment after these treatments. We also analyzed the transcripts of three citrate channel proteins and found they were up-regulated by NaCl, CuSO4, and AlCl3 but not by IM or DM. This study clarified that organic acid secretion in plants might be a common phenomenon when plants are exposed to environmental stress other than Al toxicity.

  8. Differential regulation of human cathelicidin LL-37 by free fatty acids and their analogs.

    PubMed

    Jiang, Weiyu; Sunkara, Lakshmi T; Zeng, Xiangfang; Deng, Zhuo; Myers, Sarah M; Zhang, Guolong

    2013-12-01

    LL-37 is the single cathelicidin host defense peptide in humans with direct antimicrobial and immunomodulatory activities. Specific regulation of LL-37 synthesis has emerged as a novel non-antibiotic approach to disease control and prevention. Short-chain fatty acids, and butyrate in particular, were found recently to be strong inducers of LL-37 gene expression without causing inflammation. Here, we further evaluated the LL-37-inducing efficiency of a broad range of saturated free fatty acids and their derivatives in human HT-29 colonic epithelial cells and U-937 monocytic cells by real-time RT-PCR. Surprisingly, we revealed that valerate, hexanoate, and heptanoate with 5-7 carbons are more potent than 4-carbon butyrate in promoting LL-37 gene expression in both cell types. Free fatty acids with longer than 7 or shorter than 4 carbons showed only a marginal effect on LL-37 expression. Studies with a series of fatty acid derivatives with modifications in the aliphatic chain or carboxylic acid group yielded several analogs such as benzyl butyrate, trans-cinnamyl butyrate, glyceryl tributyrate, and phenethyl butyrate with a comparable LL-37-inducing activity to sodium butyrate. On the other hand, although reactive, the anhydride derivatives of short- and medium-chain fatty acids are as potent as their corresponding free acid forms in LL-37 induction. Thus, these newly identified free fatty acids and their analogs with a strong capacity to augment LL-37 synthesis may hold promise as immune boosting dietary supplements for antimicrobial therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Nutritional and Hormonal Regulation of Citrate and Carnitine/Acylcarnitine Transporters: Two Mitochondrial Carriers Involved in Fatty Acid Metabolism

    PubMed Central

    Giudetti, Anna M.; Stanca, Eleonora; Siculella, Luisa; Gnoni, Gabriele V.; Damiano, Fabrizio

    2016-01-01

    The transport of solutes across the inner mitochondrial membrane is catalyzed by a family of nuclear-encoded membrane-embedded proteins called mitochondrial carriers (MCs). The citrate carrier (CiC) and the carnitine/acylcarnitine transporter (CACT) are two members of the MCs family involved in fatty acid metabolism. By conveying acetyl-coenzyme A, in the form of citrate, from the mitochondria to the cytosol, CiC contributes to fatty acid and cholesterol synthesis; CACT allows fatty acid oxidation, transporting cytosolic fatty acids, in the form of acylcarnitines, into the mitochondrial matrix. Fatty acid synthesis and oxidation are inversely regulated so that when fatty acid synthesis is activated, the catabolism of fatty acids is turned-off. Malonyl-CoA, produced by acetyl-coenzyme A carboxylase, a key enzyme of cytosolic fatty acid synthesis, represents a regulator of both metabolic pathways. CiC and CACT activity and expression are regulated by different nutritional and hormonal conditions. Defects in the corresponding genes have been directly linked to various human diseases. This review will assess the current understanding of CiC and CACT regulation; underlining their roles in physio-pathological conditions. Emphasis will be placed on the molecular basis of the regulation of CiC and CACT associated with fatty acid metabolism. PMID:27231907

  10. ABI4 Regulates Primary Seed Dormancy by Regulating the Biogenesis of Abscisic Acid and Gibberellins in Arabidopsis

    PubMed Central

    Shu, Kai; Zhang, Huawei; Wang, Shengfu; Chen, Mingluan; Wu, Yaorong; Tang, Sanyuan; Liu, Chunyan; Feng, Yuqi; Cao, Xiaofeng; Xie, Qi

    2013-01-01

    Seed dormancy is an important economic trait for agricultural production. Abscisic acid (ABA) and Gibberellins (GA) are the primary factors that regulate the transition from dormancy to germination, and they regulate this process antagonistically. The detailed regulatory mechanism involving crosstalk between ABA and GA, which underlies seed dormancy, requires further elucidation. Here, we report that ABI4 positively regulates primary seed dormancy, while negatively regulating cotyledon greening, by mediating the biogenesis of ABA and GA. Seeds of the Arabidopsis abi4 mutant that were subjected to short-term storage (one or two weeks) germinated significantly more quickly than Wild-Type (WT), and abi4 cotyledons greened markedly more quickly than WT, while the rates of germination and greening were comparable when the seeds were subjected to longer-term storage (six months). The ABA content of dry abi4 seeds was remarkably lower than that of WT, but the amounts were comparable after stratification. Consistently, the GA level of abi4 seeds was increased compared to WT. Further analysis showed that abi4 was resistant to treatment with paclobutrazol (PAC), a GA biosynthesis inhibitor, during germination, while OE-ABI4 was sensitive to PAC, and exogenous GA rescued the delayed germination phenotype of OE-ABI4. Analysis by qRT-PCR showed that the expression of genes involved in ABA and GA metabolism in dry and germinating seeds corresponded to hormonal measurements. Moreover, chromatin immunoprecipitation qPCR (ChIP-qPCR) and transient expression analysis showed that ABI4 repressed CYP707A1 and CYP707A2 expression by directly binding to those promoters, and the ABI4 binding elements are essential for this repression. Accordingly, further genetic analysis showed that abi4 recovered the delayed germination phenotype of cyp707a1 and cyp707a2 and further, rescued the non-germinating phenotype of ga1-t. Taken together, this study suggests that ABI4 is a key factor that

  11. Dynamic regulation of fatty acid pools for improved production of fatty alcohols in Saccharomyces cerevisiae.

    PubMed

    Teixeira, Paulo Gonçalves; Ferreira, Raphael; Zhou, Yongjin J; Siewers, Verena; Nielsen, Jens

    2017-03-15

    In vivo production of fatty acid-derived chemicals in Saccharomyces cerevisiae requires strategies to increase the intracellular supply of either acyl-CoA or free fatty acids (FFAs), since their cytosolic concentrations are quite low in a natural state for this organism. Deletion of the fatty acyl-CoA synthetase genes FAA1 and FAA4 is an effective and straightforward way to disable re-activation of fatty acids and drastically increase FFA levels. However, this strategy causes FFA over-accumulation and consequential release to the extracellular medium, which results in a significant loss of precursors that compromises the process yield. In the present study, we aimed for dynamic expression of the fatty acyl-CoA synthetase gene FAA1 to regulate FFA and acyl-CoA pools in order to improve fatty alcohol production yields. We analyzed the metabolite dynamics of a faa1Δ faa4Δ strain constitutively expressing a carboxylic acid reductase from Mycobacterium marinum (MmCAR) and an endogenous alcohol dehydrogenase (Adh5) for in vivo production of fatty alcohols from FFAs. We observed production of fatty acids and fatty alcohols with different rates leading to high levels of FFAs not being converted to the final product. To address the issue, we expressed the MmCAR + Adh5 pathway together with a fatty acyl-CoA reductase from Marinobacter aquaeolei to enable fatty alcohol production simultaneously from FFA and acyl-CoA, respectively. Then, we expressed FAA1 under the control of different promoters in order to balance FFA and acyl-CoA interconversion rates and to achieve optimal levels for conversion to fatty alcohols. Expressing FAA1 under control of the HXT1 promoter led to an increased accumulation of fatty alcohols per OD600 up to 41% while FFA levels were decreased by 63% compared with the control strain. Fine-tuning and dynamic regulation of key metabolic steps can be used to improve cell factories when the rates of downstream reactions are limiting. This avoids loss of

  12. Protein Analysis of Sapienic Acid-Treated Porphyromonas gingivalis Suggests Differential Regulation of Multiple Metabolic Pathways

    PubMed Central

    Dawson, Deborah V.; Blanchette, Derek R.; Drake, David R.; Wertz, Philip W.; Brogden, Kim A.

    2015-01-01

    ABSTRACT Lipids endogenous to skin and mucosal surfaces exhibit potent antimicrobial activity against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Our previous work demonstrated the antimicrobial activity of the fatty acid sapienic acid (C16:1Δ6) against P. gingivalis and found that sapienic acid treatment alters both protein and lipid composition from those in controls. In this study, we further examined whole-cell protein differences between sapienic acid-treated bacteria and untreated controls, and we utilized open-source functional association and annotation programs to explore potential mechanisms for the antimicrobial activity of sapienic acid. Our analyses indicated that sapienic acid treatment induces a unique stress response in P. gingivalis resulting in differential expression of proteins involved in a variety of metabolic pathways. This network of differentially regulated proteins was enriched in protein-protein interactions (P = 2.98 × 10−8), including six KEGG pathways (P value ranges, 2.30 × 10−5 to 0.05) and four Gene Ontology (GO) molecular functions (P value ranges, 0.02 to 0.04), with multiple suggestive enriched relationships in KEGG pathways and GO molecular functions. Upregulated metabolic pathways suggest increases in energy production, lipid metabolism, iron acquisition and processing, and respiration. Combined with a suggested preferential metabolism of serine, which is necessary for fatty acid biosynthesis, these data support our previous findings that the site of sapienic acid antimicrobial activity is likely at the bacterial membrane. IMPORTANCE P. gingivalis is an important opportunistic pathogen implicated in periodontitis. Affecting nearly 50% of the population, periodontitis is treatable, but the resulting damage is irreversible and eventually progresses to tooth loss. There is a great need for natural products that can be used to treat and/or prevent the overgrowth of

  13. Intracellular pH regulation by acid-base transporters in mammalian neurons.

    PubMed

    Ruffin, Vernon A; Salameh, Ahlam I; Boron, Walter F; Parker, Mark D

    2014-01-01

    Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (J L) and extrusion (J E). The balance between J E and J L determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to J L (namely the Cl-HCO3 exchanger AE3) and J E (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na(+)- coupled HCO3 (-) transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions.

  14. Jasmonic acid-dependent regulation of seed dormancy following maternal herbivory in Arabidopsis.

    PubMed

    Singh, Prashant; Dave, Anuja; Vaistij, Fabian E; Worrall, Dawn; Holroyd, Geoff H; Wells, Jonathan G; Kaminski, Filip; Graham, Ian A; Roberts, Michael R

    2017-06-01

    Maternal experience of abiotic environmental factors such as temperature and light are well known to control seed dormancy in many plant species. Maternal biotic stress alters offspring defence phenotypes, but whether it also affects seed dormancy remains unexplored. We exposed Arabidopsis thaliana plants to herbivory and investigated plasticity in germination and defence phenotypes in their offspring, along with the roles of phytohormone signalling in regulating maternal effects. Maternal herbivory resulted in the accumulation of jasmonic acid-isoleucine and loss of dormancy in seeds of stressed plants. Dormancy was also reduced by engineering seed-specific accumulation of jasmonic acid in transgenic plants. Loss of dormancy was dependent on an intact jasmonate signalling pathway and was associated with increased gibberellin content and reduced abscisic acid sensitivity during germination. Altered dormancy was only observed in the first generation following herbivory, whereas defence priming was maintained for at least two generations. Herbivory generates a jasmonic acid-dependent reduction in seed dormancy, mediated by alteration of gibberellin and abscisic acid signalling. This is a direct maternal effect, operating independently from transgenerational herbivore resistance priming. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  15. Historical perspective on the role of the kidney in acid-base regulation.

    PubMed

    Smogorzewski, Miroslaw J

    2009-01-01

    Early observations on the acidity of normal urine by J. B. von Helmont (1527-1644) and on urine content of sulfate, phosphate and carbonate by J. J. Berzelius (1779-1848), followed by the studies of Bence Jones (1813-1878) on the connection between food, nutrition and urine acidity, pointed to the role of the kidney in regulation of acid-base status in humans and animals. The next important steps in this field of science were studies by F. Walter (1877) on decreased "alkali" in blood and increased ammonia in the urine of dogs after infusion into their blood of hydrochloric acid, and the observations of B. Naunyn (1939-1925) and O. Minkowski (1853-1931) on the presence of beta-hydroxybutyric acid in urine and on increased ammonia excretion in urine from patients with diabetic coma. Also it was found that patients with uremia had decreased titratable "alkali' in blood (R. von Jaksch 1855-1947) and reduced ability to excrete ammonia (W. W. Palmer and L. J. Henderson 1915). Finally, studies by R. F. Pitts (1908-1977) defined the role of the kidney in reabsorption of bicarbonate in the tubules and linked hydrogen secretion to sodium excretion in the urine.

  16. Intracellular pH regulation by acid-base transporters in mammalian neurons

    PubMed Central

    Ruffin, Vernon A.; Salameh, Ahlam I.; Boron, Walter F.; Parker, Mark D.

    2014-01-01

    Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (JL) and extrusion (JE). The balance between JE and JL determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to JL (namely the Cl-HCO3 exchanger AE3) and JE (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na+- coupled HCO3− transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions. PMID:24592239

  17. Dietary fatty acid composition influences tissue lipid profiles and regulation of body temperature in Japanese quail.

    PubMed

    Ben-Hamo, Miriam; McCue, Marshall D; McWilliams, Scott R; Pinshow, Berry

    2011-08-01

    Many avian species reduce their body temperature (T(b)) to conserve energy during periods of inactivity, and we recently characterized how ambient temperature (T(a)) and nutritional stress interact with one another to influence physiologically controlled hypothermic responses in Japanese quail (Coturnix japonica). In the present study, we examined how the fatty acid (FA) composition of the diet influences the FA composition of phospholipids in major organs and how these affect controlled hypothermic responses and metabolic rates in fasted birds. For 5 weeks prior to fasting, quail were fed a standard diet and gavaged each morning with 0.7 ml of water (control), or a vegetable oil comprising saturated fatty acids (SFA; coconut oil), or unsaturated fatty acids (UFA; canola oil). Birds were then fasted for 4 days at a T(a) of 15°C. We found that, while fasting, both photophase and scotophase T(b) decreased significantly more in the SFA treatment group than in the control group; apparently the former down-regulated their T(b) set point. This deeper hypothermic response was correlated with changes in the phospholipid composition of the skeletal muscle and liver, which contained significantly more oleic acid (18:1) and less arachidonic acid (20:4), respectively. Our data imply that these two FAs may be associated with thermoregulation.

  18. Transcriptional regulation of rat alpha 1-acid glycoprotein gene by phenobarbital.

    PubMed

    Fournier, T; Mejdoubi, N; Lapoumeroulie, C; Hamelin, J; Elion, J; Durand, G; Porquet, D

    1994-11-04

    Phenobarbital induces gene transcription of both cytochrome P450IIB (the barbiturate-inducible cytochrome P450 in mammals) and alpha 1-acid glycoprotein, one of the major acute-phase proteins in rats and humans. Analysis of the 5'-regulatory sequences of cytochrome P450IIB and alpha 1-acid glycoprotein genes in rats revealed the presence of a consensus sequence of 10 base pairs, termed the phenobarbital-responsive element or Barbie box, located in a region extending from positions -136 to -127 from the transcription start site of the alpha 1-acid glycoprotein gene. A 17-base pair oligonucleotide probe specific for alpha 1-acid glycoprotein and including the consensus sequence showed, in mobility shift assays, slight binding to liver nuclear protein from untreated animals. This binding was strongly and specifically increased with protein extracts from phenobarbital-treated rats. Transfection of rat primary hepatocytes with the pAGPcat construct induced basal expression of chloramphenicol acetyltransferase activity, which was increased by phenobarbital and dexamethasone treatment of cells. Induction of chloramphenicol acetyltransferase activity by phenobarbital was abolished when hepatocytes were transfected by constructs with a mutation or deletion of the Barbie box sequence. These results strongly suggest that the Barbie box sequence is involved in alpha 1-acid glycoprotein gene regulation by phenobarbital.

  19. Abscisic acid sensor RCAR7/PYL13, specific regulator of protein phosphatase coreceptors.

    PubMed

    Fuchs, Stefan; Tischer, Stefanie V; Wunschel, Christian; Christmann, Alexander; Grill, Erwin

    2014-04-15

    The plant hormone abscisic acid (ABA) acts both as a developmental signal and as an integrator of environmental cues such as drought and cold. ABA perception recruits an ABA-binding regulatory component [regulatory component of ABA receptor (RCAR)/PYR1/PYL] and an associated protein phosphatase 2C (PP2C). Phytohormone binding inactivates the phosphatase activity of the coreceptor, permitting phosphorelay of the ABA signal via downstream protein kinases. RCARs and PP2C coreceptors are represented by small protein families comprising 14 and 9 members in Arabidopsis, respectively. The specificity of the RCAR-PP2C interaction and the constraints contributing to specific combinations are poorly understood. In this contribution, we analyzed RCAR7/PYL13, which is characterized by three variant amino acid residues in the conserved ABA-binding pocket. RCAR7 regulated the phosphatase activity of the PP2Cs ABI1, ABI2, and PP2CA in vitro at nanomolar ABA levels; however, it was unable to regulate the structurally related hypersensitive to ABA 1 (HAB1). Site-directed mutagenesis of HAB1 established ABA-dependent regulation by RCAR7. Conversion of the noncanonical amino acid residues of RCAR7 into the consensus ABA-binding pocket did not perceptibly change receptor function. Ectopic expression of RCAR7 in Arabidopsis resulted in ABA hypersensitivity affecting gene regulation, seed germination, and stomatal closure. The RCAR7 loss-of-function mutant revealed no changes in ABA responses, similar to the RCAR9 knockout line, whereas the combined deficiency of RCAR7 and RCAR9 resulted in ABA-insensitive seed germination. The study shows a role of RCAR7 in early plant development, proves its ABA receptor function, and identifies structural constraints of RCAR7-PP2C interaction.

  20. Impact of salicylic acid- and jasmonic acid-regulated defences on root colonization by Trichoderma harzianum T-78.

    PubMed

    Martínez-Medina, Ainhoa; Appels, Freek V W; van Wees, Saskia C M

    2017-07-10

    We recently found that the beneficial fungus Trichoderma harzianum T-78 primes tomato plants for salicylic acid (SA)- and jasmonic acid (JA)-regulated defenses, resulting in enhanced resistance against the root knot nematode Meloidogyne incognita. By using SA- and JA-impaired mutant lines and exogenous hormonal application, here we investigated whether the SA- and JA-pathways also have a role in T-78 root colonization of Arabidopsis thaliana. Endophytic colonization by T-78 was faster in the SA-impaired mutant sid2 than in the wild type. Moreover, elicitation of SA-dependent defenses by SA application reduced T-78 colonization, indicating that the SA-pathway affects T-78 endophytism. In contrast, elicitation of the JA-pathway, which antagonized SA-dependent defenses, resulted in enhanced endophytic colonization by T-78. These findings are in line with our previous observation that SA-dependent defenses are repressed by T-78, which likely aids colonization by the endophytic fungus.

  1. Ozone-Induced Vascular Contractility and Pulmonary Injury Are Differently Impacted by Coconut, Fish and Olive Oil-Rich diets

    EPA Science Inventory

    The omega-3 polyunsaturated fatty acids present in fish oil supplements are proposed to offer cardioprotective benefits, but it is not established if these supplements can protect against the adverse health effects induced by exposure to air pollution. Ozone, an ubiquitous air p...

  2. Nrf2- and PPARα-Mediated Regulation of Hepatic Mrp Transporters after Exposure to Perfluorooctanoic Acid and Perfluorodecanoic Acid

    PubMed Central

    Maher, Jonathan M.; Aleksunes, Lauren M.; Dieter, Matthew Z.; Tanaka, Yuji; Peters, Jeffrey M.; Manautou, Jose E.; Klaassen, Curtis D.

    2008-01-01

    Perfluorooctanoic acid and perfluorodecanoic acid (PFDA) are commonly used as emulsifiers and surfactants in fluoropolymer manufacturing and are known peroxisome proliferator–activated receptor alpha (PPARα) agonists. PPARα activation induces β- and ω-oxidation enzymes such as Cyp4a14 and acyl-CoA oxidase, which are a likely cause of subsequent oxidative stress and peroxisome proliferation. Conversely, NF-E2-related factor-2 (Nrf2) is a transcription factor that protects against oxidative stress and inflammation by regulating several detoxification and xenobiotic transporter genes. Because PFDA markedly induces hepatic metabolism and oxidative stress, we hypothesized that PFDA exposure would increase expression of hepatic efflux multidrug resistance–associated protein (Mrp) transporters. A single PFDA dose (80 mg/kg) administered to mice increased hepatic Mrp3 (fourfold) and Mrp4 (31-fold) mRNA expression. Upregulation of Mrp3 and Mrp4 correlated with elevated serum-conjugated bilirubin and bile acids, respectively. To determine the mechanism of Mrp3 and Mrp4 induction, PFDA was administered to Nrf2-null mice, PPARα-null mice, and mice pretreated with gadolinium chloride, a Kupffer cell–depleting chemical capable of inhibiting the inflammatory cytokine response. In both PPARα- and Nrf2-null mice, maximal induction of Mrp3 and Mrp4 mRNA after PFDA administration was attenuated. Gadolinium chloride pretreatment reduced serum and hepatic tumor necrosis factor-α levels after PFDA treatment, as well as Mrp4 mRNA expression by 30%, suggesting that Kupffer cell–derived mediators may contribute to Mrp induction. Thus, after PFDA administration, the liver mounts a compensatory hepatoprotective response via PPARα and Nrf2, markedly increasing Mrp3 and Mrp4 expression, with corresponding increases in serum of known Mrp3 and Mrp4 substrates. PMID:18757529

  3. Abscisic acid and sucrose regulate tomato and strawberry fruit ripening through the abscisic acid-stress-ripening transcription factor.

    PubMed

    Jia, Haifeng; Jiu, Songtao; Zhang, Cheng; Wang, Chen; Tariq, Pervaiz; Liu, Zhongjie; Wang, Baoju; Cui, Liwen; Fang, Jinggui

    2016-10-01

    Although great progress has been made towards understanding the role of abscisic acid (ABA) and sucrose in fruit ripening, the mechanisms underlying the ABA and sucrose signalling pathways remain elusive. In this study, transcription factor ABA-stress-ripening (ASR), which is involved in the transduction of ABA and sucrose signalling pathways, was isolated and analysed in the nonclimacteric fruit, strawberry and the climacteric fruit, tomato. We have identified four ASR isoforms in tomato and one in strawberry. All ASR sequences contained the ABA stress- and ripening-induced proteins and water-deficit stress-induced proteins (ABA/WDS) domain and all ASR transcripts showed increased expression during fruit development. The expression of the ASR gene was influenced not only by sucrose and ABA, but also by jasmonic acid (JA) and indole-3-acetic acid (IAA), and these four factors were correlated with each other during fruit development. ASR bound the hexose transporter (HT) promoter, which contained a sugar box that activated downstream gene expression. Overexpression of the ASR gene promoted fruit softening and ripening, whereas RNA interference delayed fruit ripening, as well as affected fruit physiological changes. Change in ASR gene expression influenced the expression of several ripening-related genes such as CHS, CHI, F3H, DFR, ANS, UFGT, PG, PL, EXP1/2, XET16, Cel1/2 and PME. Taken together, this study may provide new evidence on the important role of ASR in cross-signalling between ABA and sucrose to regulate tomato and strawberry fruit ripening. The findings of this study also provide new insights into the regulatory mechanism underlying fruit development. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  4. CD44 Binding to Hyaluronic Acid Is Redox Regulated by a Labile Disulfide Bond in the Hyaluronic Acid Binding Site

    PubMed Central

    Kellett-Clarke, Helena; Stegmann, Monika; Barclay, A. Neil; Metcalfe, Clive

    2015-01-01

    CD44 is the primary leukocyte cell surface receptor for hyaluronic acid (HA), a component of the extracellular matrix. Enzymatic post translational cleavage of labile disulfide bonds is a mechanism by which proteins are structurally regulated by imparting an allosteric change and altering activity. We have identified one such disulfide bond in CD44 formed by Cys77 and Cys97 that stabilises the HA binding groove. This bond is labile on the surface of leukocytes treated with chemical and enzymatic reducing agents. Analysis of CD44 crystal structures reveal the disulfide bond to be solvent accessible and in the–LH hook configuration characteristic of labile disulfide bonds. Kinetic trapping and binding experiments on CD44-Fc chimeric proteins show the bond is preferentially reduced over the other disulfide bonds in CD44 and reduction inhibits the CD44-HA interaction. Furthermore cells transfected with CD44 no longer adhere to HA coated surfaces after pre-treatment with reducing agents. The implications of CD44 redox regulation are discussed in the context of immune function, disease and therapeutic strategies. PMID:26379032

  5. Recent Advances in Understanding Amino Acid Sensing Mechanisms that Regulate mTORC1

    PubMed Central

    Zheng, Liufeng; Zhang, Wei; Zhou, Yuanfei; Li, Fengna; Wei, Hongkui; Peng, Jian

    2016-01-01

    The mammalian target of rapamycin (mTOR) is the central regulator of mammalian cell growth, and is essential for the formation of two structurally and functionally distinct complexes: mTORC1 and mTORC2. mTORC1 can sense multiple cues such as nutrients, energy status, growth factors and hormones to control cell growth and proliferation, angiogenesis, autophagy, and metabolism. As one of the key environmental stimuli, amino acids (AAs), especially leucine, glutamine and arginine, play a crucial role in mTORC1 activation, but where and how AAs are sensed and signal to mTORC1 are not fully understood. Classically, AAs activate mTORC1 by Rag GTPases which recruit mTORC1 to lysosomes, where AA signaling initiates. Plasma membrane transceptor L amino acid transporter 1 (LAT1)-4F2hc has dual transporter-receptor function that can sense extracellular AA availability upstream of mTORC1. The lysosomal AA sensors (PAT1 and SLC38A9) and cytoplasmic AA sensors (LRS, Sestrin2 and CASTOR1) also participate in regulating mTORC1 activation. Importantly, AAs can be sensed by plasma membrane receptors, like G protein-coupled receptor (GPCR) T1R1/T1R3, and regulate mTORC1 without being transported into the cells. Furthermore, AA-dependent mTORC1 activation also initiates within Golgi, which is regulated by Golgi-localized AA transporter PAT4. This review provides an overview of the research progress of the AA sensing mechanisms that regulate mTORC1 activity. PMID:27690010

  6. Retinoic acid-dependent regulation of miR-19 expression elicits vertebrate axis defects

    PubMed Central

    Franzosa, Jill A.; Bugel, Sean M.; Tal, Tamara L.; La Du, Jane K.; Tilton, Susan C.; Waters, Katrina M.; Tanguay, Robert L.

    2013-01-01

    Retinoic acid (RA) is involved in multifarious and complex functions necessary for vertebrate development. RA signaling is reliant on strict enzymatic regulation of RA synthesis and metabolism. Improper spatiotemporal expression of RA during development can result in vertebrate axis defects. microRNAs (miRNAs) are also pivotal in orchestrating developmental processes. While mechanistic links between miRNAs and axial development are established, the role of miRNAs in regulating metabolic enzymes responsible for RA abundance during axis formation has yet to be elucidated. Our results uncovered a role of miR-19 family members in controlling RA metabolism through the regulation of CYP26A1 during vertebrate axis formation. Global miRNA expression profiling showed that developmental RA exposure suppressed the expression of miR-19 family members during zebrafish somitogenesis. A reporter assay confirmed that cyp26a1 is a bona fide target of miR-19 in vivo. Transient knockdown of miR-19 phenocopied axis defects caused by RA exposure. Exogenous miR-19 rescued the axis defects induced by RA exposure. Taken together, these results indicate that the teratogenic effects of RA exposure result, in part, from repression of miR-19 expression and subsequent misregulation of cyp26a1. This highlights a previously unidentified role of miR-19 in facilitating vertebrate axis development via regulation of RA signaling.—Franzosa, J. A., Bugel, S. M., Tal, T. L., La Du, J. K., Tilton, S. C., Waters, K. M., Tanguay, R. L. Retinoic acid-dependent regulation of miR-19 expression elicits vertebrate axis defects. PMID:23975936

  7. Action of Plant Growth Regulators. IV. Adsorption of Unsubstituted and 2,6-Dichloro-aromatic Acids to Oat Monolayers

    PubMed Central

    Brian, R. C.

    1967-01-01

    The adsorption of chloro-aromatic acids to monomolecular layers of oat squashes is reported in earlier papers but it was not possible by the technique used, to measure unambiguously the adsorption of unsubstituted and 2,6-dichloro-aromatic acids. This has now been achieved by a modification of the earlier method and involves assessments of competitive adsorption between the unknown acid and a standard acid, using measurements of surface potential. Benzoic and phenoxyacetic acids were not adsorbed but phenylacetic acid was weakly adsorbed. The second ring in naphthalene and naphthoxyacetic acids greatly increased adsorption. Substitution of the 2 and 6 positions in the phenyl and phenoxyacetic acids resulted in low adsorption but 2,6-disubstituted phenoxybutyric and benzoic acids were more highly adsorbed. The adsorption values from earlier work are combined and discussed in relation to the growth-regulating activity of the acids. It is conciuded that there is no direct relation embracing all acids between adsorption and activity, notable exceptions being those substituted by chlorine in the 3-position of the aromatic ring. However, for a number of acids it is suggested that activity is limited not only by their ability to interact at enzyme sites but also by the amount of acid immobilised by adsorption when moving to these sites. It is also concluded that the hydrophilic/lipophilic balance of a growth regulator sometimes used as a guide to its activity, is an unreliable indication of interfacial behaviour. PMID:16656642

  8. Action of Plant Growth Regulators. IV. Adsorption of Unsubstituted and 2,6-Dichloro-aromatic Acids to Oat Monolayers.

    PubMed

    Brian, R C

    1967-09-01

    The adsorption of chloro-aromatic acids to monomolecular layers of oat squashes is reported in earlier papers but it was not possible by the technique used, to measure unambiguously the adsorption of unsubstituted and 2,6-dichloro-aromatic acids. This has now been achieved by a modification of the earlier method and involves assessments of competitive adsorption between the unknown acid and a standard acid, using measurements of surface potential.Benzoic and phenoxyacetic acids were not adsorbed but phenylacetic acid was weakly adsorbed. The second ring in naphthalene and naphthoxyacetic acids greatly increased adsorption. Substitution of the 2 and 6 positions in the phenyl and phenoxyacetic acids resulted in low adsorption but 2,6-disubstituted phenoxybutyric and benzoic acids were more highly adsorbed.The adsorption values from earlier work are combined and discussed in relation to the growth-regulating activity of the acids. It is conciuded that there is no direct relation embracing all acids between adsorption and activity, notable exceptions being those substituted by chlorine in the 3-position of the aromatic ring. However, for a number of acids it is suggested that activity is limited not only by their ability to interact at enzyme sites but also by the amount of acid immobilised by adsorption when moving to these sites. It is also concluded that the hydrophilic/lipophilic balance of a growth regulator sometimes used as a guide to its activity, is an unreliable indication of interfacial behaviour.

  9. White sturgeon (Acipenser transmontanus) acid-base regulation differs in response to different types of acidoses.

    PubMed

    Shartau, Ryan B; Baker, Dan W; Brauner, Colin J

    2017-03-11

    White sturgeon (Acipenser transmontanus) completely protect intracellular tissue pH (pHi) despite large reductions in extracellular (blood) pH (pHe), termed preferential pHi regulation, in response to elevated environmental PCO2 (hypercarbia) and in general appear to be relatively resilient to stressors. Preferential pHi regulation is thought to be associated with hypercarbia tolerance in general, but has also recently been observed to protect pHi against metabolic acidoses induced by exhaustive exercise and anoxia in a tropical air breathing catfish. We hypothesized that preferential pHi regulation may also be a general strategy of acid-base regulation in sturgeon. To address this hypothesis, severe acidoses were imposed to reduce pHe, and the presence or absence of preferential pHi regulation was assessed in red blood cells (RBC), heart, brain, liver and white muscle. A respiratory acidosis was imposed using hyperoxia, while metabolic acidoses were induced by exhaustive exercise, anoxia or air exposure. Reductions in pHe occurred following hyperoxia (0.15 units), exhaustive exercise (0.30 units), anoxia (0.10 units) and air exposure (0.35 units); all acidoses reduced RBC pHi. Following hyperoxia, heart, brain and liver pHi were preferentially regulated against the reduction in pHe, similar to hypercarbia exposure. Following all metabolic acidoses heart pHi was protected and brain pHi remained unchanged following exhaustive exercise and air exposure, however, brain pHi was reduced following anoxia. Liver and white muscle pHi were reduced following all metabolic acidoses. These results suggest preferential pHi regulation may be a general strategy during respiratory acidoses but during metabolic acidoses, the response differs between source of acidoses and tissues.

  10. Drosophila TRF2 and TAF9 regulate lipid droplet size and phospholipid fatty acid composition

    PubMed Central

    Fan, Wei; Lam, Sin Man; Xin, Jingxue; Yang, Xiao; Liu, Zhonghua; Liu, Yuan; Wang, Yong; Shui, Guanghou

    2017-01-01

    The general transcription factor TBP (TATA-box binding protein) and its associated factors (TAFs) together form the TFIID complex, which directs transcription initiation. Through RNAi and mutant analysis, we identified a specific TBP family protein, TRF2, and a set of TAFs that regulate lipid droplet (LD) size in the Drosophila larval fat body. Among the three Drosophila TBP genes, trf2, tbp and trf1, only loss of function of trf2 results in increased LD size. Moreover, TRF2 and TAF9 regulate fatty acid composition of several classes of phospholipids. Through RNA profiling, we found that TRF2 and TAF9 affects the transcription of a common set of genes, including peroxisomal fatty acid β-oxidation-related genes that affect phospholipid fatty acid composition. We also found that knockdown of several TRF2 and TAF9 target genes results in large LDs, a phenotype which is similar to that of trf2 mutants. Together, these findings provide new insights into the specific role of the general transcription machinery in lipid homeostasis. PMID:28273089

  11. Drosophila TRF2 and TAF9 regulate lipid droplet size and phospholipid fatty acid composition.

    PubMed

    Fan, Wei; Lam, Sin Man; Xin, Jingxue; Yang, Xiao; Liu, Zhonghua; Liu, Yuan; Wang, Yong; Shui, Guanghou; Huang, Xun

    2017-03-01

    The general transcription factor TBP (TATA-box binding protein) and its associated factors (TAFs) together form the TFIID complex, which directs transcription initiation. Through RNAi and mutant analysis, we identified a specific TBP family protein, TRF2, and a set of TAFs that regulate lipid droplet (LD) size in the Drosophila larval fat body. Among the three Drosophila TBP genes, trf2, tbp and trf1, only loss of function of trf2 results in increased LD size. Moreover, TRF2 and TAF9 regulate fatty acid composition of several classes of phospholipids. Through RNA profiling, we found that TRF2 and TAF9 affects the transcription of a common set of genes, including peroxisomal fatty acid β-oxidation-related genes that affect phospholipid fatty acid composition. We also found that knockdown of several TRF2 and TAF9 target genes results in large LDs, a phenotype which is similar to that of trf2 mutants. Together, these findings provide new insights into the specific role of the general transcription machinery in lipid homeostasis.

  12. Manipulation of partially oriented hydroxyapatite building blocks to form flowerlike bundles without acid-base regulation.

    PubMed

    Wen, Zhenliang; Wang, Zihao; Chen, Jingdi; Zhong, Shengnan; Hu, Yimin; Wang, Jianhua; Zhang, Qiqing

    2016-06-01

    The application of hydroxyapatite (HAP) in different fields depends greatly on its morphology, composition and structure. Besides, the main inorganic building blocks of human bones and teeth are also HAP. Therefore, accurate shape and aggregation control and of hydroxyapatite particles will be of great interest. Herein, oriented bundles of flowerlike HAP nanorods were successfully prepared through hydrothermal treatment without acid-base regulation, with the mono-alkyl phosphate (MAP) and sodium citrate as surfactant and chelating agent, respectively. The prepared samples were characterized by the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and zeta potential, the pH value and conductivity value of suspension were characterized by pH meter and conductivity measurement. The results showed that the MAP and citrate play an important role in assembly of HAP nanorods without acid-base regulation. Citrate calcium complex could decompose slowly and release citrate ions at hydrothermal conditions. Besides, the further decomposition of citrate ions could release aconitic acid as the reaction time prolongs. Moreover, the possible scheme for the formation process was discussed in detail. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Inhibition of Fatty Acid Synthase Reduces Blastocyst Hatching through Regulation of the AKT Pathway in Pigs

    PubMed Central

    Guo, Jing; Kim, Nam-Hyung; Cui, Xiang-Shun

    2017-01-01

    Fatty acid synthase (FASN) is an enzyme responsible for the de novo synthesis of long-chain fatty acids. During oncogenesis, FASN plays a role in growth and survival rather than acting within the energy storage pathways. Here, the function of FASN during early embryonic development was studied using its specific inhibitor, C75. We found that the presence of the inhibitor reduced blastocyst hatching. FASN inhibition decreased Cpt1 expression, leading to a reduction in mitochondria numbers and ATP content. This inhibition of FASN resulted in the down-regulation of the AKT pathway, thereby triggering apoptosis through the activation of the p53 pathway. Activation of the apoptotic pathway also leads to increased accumulation of reactive oxygen species and autophagy. In addition, the FASN inhibitor impaired cell proliferation, a parameter of blastocyst quality for outgrowth. The level of OCT4, an important factor in embryonic development, decreased after treatment with the FASN inhibitor. These results show that FASN exerts an effect on early embryonic development by regulating both fatty acid oxidation and the AKT pathway in pigs. PMID:28107461

  14. Glucocorticoid regulation of amino acid transport in anucleate rat hepatoma (HTC) cells

    PubMed Central

    1981-01-01

    The transport of alpha-aminoisobutyric acid (AIB) by rat hepatoma tissue culture (HTC) cells is rapidly and reversibly inhibited by dexamethasone and other glucocorticoids. To investigate the role of the nucleus in the regulation of transport and to determine whether steroid hormones or steroid-receptor complexes may have direct effects on cytoplasmic or membrane functions, we have examined the regulation of transport by dexamethasone in anucleate HTC cells. Cytoplasts prepared from suspension cultures of HTC cells fully retain active transport of AIB with the same kinetic properties as intact cells. However, the uptake of AIB is not inhibited by dexamethasone or other corticosteroids. Neither is the inhibited rate of transport, manifested by cytoplasts prepared from dexamethasone-treated cells, restored to normal upon removal of the hormone. Anucleate cells exhibit specific, saturable binding of [3H]dexamethasone; however, the binding is reduced compared with that of intact cells. The nucleus is thus required for the glucocorticoid regulation of amino acid transport in HTC cells. PMID:7217203

  15. Transcriptome profiling revealed novel transcriptional regulators in maize responses to Ostrinia furnacalis and jasmonic acid

    PubMed Central

    Teng, Shouzhen; Liang, Haisheng; Xin, Hongjia; Gao, Hongjiang; Huang, Dafang

    2017-01-01

    Chewing insects cause severe yield losses in crop production worldwide. Crop plants counteract chewing insects by transcriptionally promoting a repertoire of defense gene products that are either toxic to, or attractive to the natural enemies of, pest insects. However, the complexity of the transcriptional reprogramming in plant defense response against chewing insects is still not well understood. In this study, the genome-wide early responses in maize seedlings to Asian corn borer (ACB, Ostrinia furnacalis) and also to jasmonic acid(JA), the pivotal phytohormone controlling plant defense response against herbivory, were transcriptionally profiled by RNA-Seq. Clustering of differentially expressed genes (DEGs) along with functional enrichment analysis revealed important biological processes regulated in response to ACB infestation and/or jasmonic acid. Moreover, DEGs with distinct expression patterns were differentially enriched with diverse families of cis-elements on their promoters. Multiple inventories of differentially expressed transcription factors (DETFs) in each DEG group were also analyzed. A transient expression assay using transfected maize protoplastswas established to examine the potential roles of DETFs in maize defense response and JA signaling, and this was used to show that ZmNAC60, an ACB- and JA-inducible DETF, represented a novel positive regulator of JA and defense pathway genes. This study provided a comprehensive transcriptional picture for the early dynamics of maize defense responses and JA signaling, and the identification of DETFs offered potential targets for further functional genomics investigation of master regulators in maize defense responses against herbivory. PMID:28520800

  16. Transcriptome profiling revealed novel transcriptional regulators in maize responses to Ostrinia furnacalis and jasmonic acid.

    PubMed

    Wang, Hai; Li, Shengyan; Teng, Shouzhen; Liang, Haisheng; Xin, Hongjia; Gao, Hongjiang; Huang, Dafang; Lang, Zhihong

    2017-01-01

    Chewing insects cause severe yield losses in crop production worldwide. Crop plants counteract chewing insects by transcriptionally promoting a repertoire of defense gene products that are either toxic to, or attractive to the natural enemies of, pest insects. However, the complexity of the transcriptional reprogramming in plant defense response against chewing insects is still not well understood. In this study, the genome-wide early responses in maize seedlings to Asian corn borer (ACB, Ostrinia furnacalis) and also to jasmonic acid(JA), the pivotal phytohormone controlling plant defense response against herbivory, were transcriptionally profiled by RNA-Seq. Clustering of differentially expressed genes (DEGs) along with functional enrichment analysis revealed important biological processes regulated in response to ACB infestation and/or jasmonic acid. Moreover, DEGs with distinct expression patterns were differentially enriched with diverse families of cis-elements on their promoters. Multiple inventories of differentially expressed transcription factors (DETFs) in each DEG group were also analyzed. A transient expression assay using transfected maize protoplastswas established to examine the potential roles of DETFs in maize defense response and JA signaling, and this was used to show that ZmNAC60, an ACB- and JA-inducible DETF, represented a novel positive regulator of JA and defense pathway genes. This study provided a comprehensive transcriptional picture for the early dynamics of maize defense responses and JA signaling, and the identification of DETFs offered potential targets for further functional genomics investigation of master regulators in maize defense responses against herbivory.

  17. Nutrigenomics, rumen-derived bioactive fatty acids, and the regulation of milk fat synthesis.

    PubMed

    Bauman, Dale E; Harvatine, Kevin J; Lock, Adam L

    2011-08-21

    Mammary synthesis of milk fat continues to be an active research area, with significant advances in the regulation of lipid synthesis by bioactive fatty acids (FAs). The biohydrogenation theory established that diet-induced milk fat depression (MFD) in the dairy cow is caused by an inhibition of mammary synthesis of milk fat by specific FAs produced during ruminal biohydrogenation. The first such FA shown to affect milk fat synthesis was trans-10, cis-12 conjugated linoleic acid, and its effects have been well characterized, including dose-response relationships. During MFD, lipogenic capacity and transcription of key mammary lipogenic genes are coordinately down-regulated. Results provide strong evidence for sterol response element-binding protein-1 (SREBP1) and Spot 14 as biohydrogenation intermediate responsive lipogenic signaling pathway for ruminants and rodents. The study of MFD and its regulation by specific rumen-derived bioactive FAs represents a successful example of nutrigenomics in present-day animal nutrition research and offers several potential applications in animal agriculture.

  18. Retinoic acid receptor regulation of epimorphic and homeostatic regeneration in the axolotl.

    PubMed

    Nguyen, Matthew; Singhal, Pankhuri; Piet, Judith W; Shefelbine, Sandra J; Maden, Malcolm; Voss, S Randal; Monaghan, James R

    2017-02-15

    Salamanders are capable of regenerating amputated limbs by generating a mass of lineage-restricted cells called a blastema. Blastemas only generate structures distal to their origin unless treated with retinoic acid (RA), which results in proximodistal (PD) limb duplications. Little is known about the transcriptional network that regulates PD duplication. In this study, we target specific retinoic acid receptors (RARs) to either PD duplicate (RA treatment or RARγ agonist) or truncate (RARβ antagonist) regenerating limbs. RARE-EGFP reporter axolotls showed divergent reporter activity in limbs undergoing PD duplication versus truncation, suggesting differences in patterning and skeletal regeneration. Transcriptomics identified expression patterns that explain PD duplication, including upregulation of proximal homeobox gene expression and silencing of distal-associated genes, whereas limb truncation was associated with disrupted skeletal differentiation. RARβ antagonism in uninjured limbs induced a loss of skeletal integrity leading to long bone regression and loss of skeletal turnover. Overall, mechanisms were identified that regulate the multifaceted roles of RARs in the salamander limb including regulation of skeletal patterning during epimorphic regeneration, skeletal tissue differentiation during regeneration, and homeostatic regeneration of intact limbs.

  19. A C-Terminal Acidic Domain Regulates Degradation of the Transcriptional Coactivator Bob1

    PubMed Central

    Wong, Christina S. F.; Möller, Andreas

    2013-01-01

    Bob1 (Obf-1 or OCA-B) is a 34-kDa transcriptional coactivator encoded by the Pou2af1 gene that is essential for normal B-cell development and immune responses in mice. During lymphocyte activation, Bob1 protein levels dramatically increase independently of mRNA levels, suggesting that the stability of Bob1 is regulated. We used a fluorescent protein-based reporter system to analyze protein stability in response to genetic and physiological perturbations and show that, while Bob1 degradation is proteasome mediated, it does not require ubiquitination of Bob1. Furthermore, degradation of Bob1 in B cells appears to be largely independent of the E3 ubiquitin ligase Siah. We propose a novel mechanism of Bob1 turnover in B cells, whereby an acidic region in the C terminus of Bob1 regulates the activity of degron signals elsewhere in the protein. Changes that make the C terminus more acidic, including tyrosine phosphorylation-mimetic mutations, stabilize the instable murine Bob1 protein, indicating that B cells may regulate Bob1 stability and activity via signaling pathways. Finally, we show that expressing a stable Bob1 mutant in B cells suppresses cell proliferation and induces changes in surface marker expression commonly seen during B-cell differentiation. PMID:24061476

  20. Role of Vitamin A/Retinoic Acid in Regulation of Embryonic and Adult Hematopoiesis

    PubMed Central

    Cañete, Ana; Cano, Elena; Muñoz-Chápuli, Ramón; Carmona, Rita

    2017-01-01

    Vitamin A is an essential micronutrient throughout life. Its physiologically active metabolite retinoic acid (RA), acting through nuclear retinoic acid receptors (RARs), is a potent regulator of patterning during embryonic development, as well as being necessary for adult tissue homeostasis. Vitamin A deficiency during pregnancy increases risk of maternal night blindness and anemia and may be a cause of congenital malformations. Childhood Vitamin A deficiency can cause xerophthalmia, lower resistance to infection and increased risk of mortality. RA signaling appears to be essential for expression of genes involved in developmental hematopoiesis, regulating the endothelial/blood cells balance in the yolk sac, promoting the hemogenic program in the aorta-gonad-mesonephros area and stimulating eryrthropoiesis in fetal liver by activating the expression of erythropoietin. In adults, RA signaling regulates differentiation of granulocytes and enhances erythropoiesis. Vitamin A may facilitate iron absorption and metabolism to prevent anemia and plays a key role in mucosal immune responses, modulating the function of regulatory T cells. Furthermore, defective RA/RARα signaling is involved in the pathogenesis of acute promyelocytic leukemia due to a failure in differentiation of promyelocytes. This review focuses on the different roles played by vitamin A/RA signaling in physiological and pathological mouse hematopoiesis duddurring both, embryonic and adult life, and the consequences of vitamin A deficiency for the blood system. PMID:28230720

  1. Coordinate regulation of glycolytic and lipogenic gene expression by polyunsaturated fatty acids.

    PubMed

    Jump, D B; Clarke, S D; Thelen, A; Liimatta, M

    1994-06-01

    Using a combination of in vivo and in vitro studies, we have investigated the impact of polyunsaturated fatty acids (PUFA) on the expression of several genes encoding proteins involved in hepatic glycolysis and lipogenesis. Meal-training rats to a high glucose diet containing 10% triolein led to a significant induction of hepatic mRNAs encoding glucokinase (GK), pyruvate kinase (PK), fatty acid synthase (FAS), malic enzyme (ME), and the S14 protein (S14), but had no effect on thyroid hormone receptor-beta 1 (TR beta 1) and c/EBP alpha gene expression. Replacing triolein with menhaden oil attenuated (by 50-90%) the induction of mRNA encoding GK, ME, PK, FAS, and S14. This effect was rapid (within hours) and for FAS and S14, directed at the transcriptional level. The mRNAs encoding TR beta 1, c/EBP alpha and beta-actin were unaffected by menhaden oil. Studies with cultured primary hepatocytes showed that C18:3,omega 3 (n-3), C18:3,omega 6 (n-6), C20:4, omega 6 (n-6), and C20:5,omega 3 (n-3) were all equally effective at suppressing the level of mRNAs encoding FAS, S14, and PK. This effect was specific for glycolytic and lipogenic enzymes, as expression of beta-actin was not affected by these fatty acids. Moreover, the fatty acids had only marginal effects on cell viability as judged by lactate dehydrogenase release. These data indicate that polyunsaturated fatty acids coordinately regulate the expression of several enzymes involved in carbohydrate and lipid metabolism. The mechanism of control does not require extrahepatic factors or fatty acid metabolism.

  2. Chelidonic acid evokes antidepressant-like effect through the up-regulation of BDNF in forced swimming test

    PubMed Central

    Jeong, Hyun-Ja; Yang, Shi-Young; Kim, Hee-Yun; Kim, Na-Rae; Jang, Jae-Bum

    2016-01-01

    Depression is usually accompanied by neuro-inflammatory reactions. Chelidonic acid, in particular, has shown anti-inflammatory effects. The objective of this study was to evaluate the anti-depressant effects of chelidonic acid and to discuss the potential mechanisms of a forced swimming test. Chelidonic acid was administered orally once a day for 14 days. On the 14th day, chelidonic acid resulted in a significant decrease in immobility time during the forced swimming test without alteration of locomotor activity, in an open field test. Chelidonic acid also increased the number of nissl bodies in the hippocampus. Brain-derived neurotrophic factor expression and extracellular signal-regulated protein kinase phosphorylation in the hippocampus were up-regulated by the administration of chelidonic acid. Chelidonic acid administration significantly increased the mRNA expression of hippocampal estrogen receptor-β. The levels of hippocampal interleukin (IL)-1β, IL-6, and tumor necrosis factor-α were effectively attenuated by the administration of chelidonic acid. In addition, chelidonic acid significantly increased the levels of 5-hydroxytryptamine (serotonin), dopamine, and norepinephrine compared with those levels for the mice that were administered distilled water in the hippocampus. These results suggest that chelidonic acid might serve as a new therapeutic strategy for the regulation of depression associated with inflammation. PMID:27037280

  3. Chelidonic acid evokes antidepressant-like effect through the up-regulation of BDNF in forced swimming test.

    PubMed

    Jeong, Hyun-Ja; Yang, Shi-Young; Kim, Hee-Yun; Kim, Na-Rae; Jang, Jae-Bum; Kim, Hyung-Min

    2016-08-01

    Depression is usually accompanied by neuro-inflammatory reactions. Chelidonic acid, in particular, has shown anti-inflammatory effects. The objective of this study was to evaluate the anti-depressant effects of chelidonic acid and to discuss the potential mechanisms of a forced swimming test. Chelidonic acid was administered orally once a day for 14 days. On the 14th day, chelidonic acid resulted in a significant decrease in immobility time during the forced swimming test without alteration of locomotor activity, in an open field test. Chelidonic acid also increased the number of nissl bodies in the hippocampus. Brain-derived neurotrophic factor expression and extracellular signal-regulated protein kinase phosphorylation in the hippocampus were up-regulated by the administration of chelidonic acid. Chelidonic acid administration significantly increased the mRNA expression of hippocampal estrogen receptor-β. The levels of hippocampal interleukin (IL)-1β, IL-6, and tumor necrosis factor-α were effectively attenuated by the administration of chelidonic acid. In addition, chelidonic acid significantly increased the levels of 5-hydroxytryptamine (serotonin), dopamine, and norepinephrine compared with those levels for the mice that were administered distilled water in the hippocampus. These results suggest that chelidonic acid might serve as a new therapeutic strategy for the regulation of depression associated with inflammation. © 2016 by the Society for Experimental Biology and Medicine.

  4. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    SciTech Connect

    Zeikus, J.G.; Jain, M.

    1993-12-31

    The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron carrier analysis using Butyribacterium methylotrophicum, Anaeroblospirillum succiniciproducens, Methanosarcina barkeri, and a newly isolated tri-culture composed of a syntrophic butyrate degrader strain IB, Methanosarcina mazei and Methanobacterium formicicum as model systems. To understand the regulation of hydrogen metabolism during butyrate production or acetate degradation, hydrogenase activity in B. methylotrophicum or M. barkeri is measured in relation to growth substrate and pH; hydrogenase is purified and characterized to investigate number of hydrogenases; their localization and functions; and, their sequences are determined. To understand the mechanism for catabolic CO{sub 2} fixation to succinate the PEP carboxykinase enzyme and gene of A. succiniciproducens are purified and characterized. Genetically engineered strains of Escherichia coli containing the phosphoenolpyruvate (PEP) carboxykinase gene are examined for their ability to produce succinate in high yield. To understand the mechanism of fatty acid degradation by syntrophic acetogens during mixed culture methanogenesis formate and hydrogen production are characterized by radio tracer studies. It is intended that these studies provide strategies to improve anaerobic fermentations used for the production of organic acids or methane and, new basic understanding on catabolic CO{sub 2} fixation mechanisms and on the function of hydrogenase in anaerobic bacteria.

  5. Na+/H+ exchangers in renal regulation of acid-base balance.

    PubMed

    Bobulescu, I Alexandru; Moe, Orson W

    2006-09-01

    The kidney plays key roles in extracellular fluid pH homeostasis by reclaiming bicarbonate (HCO(3)(-)) filtered at the glomerulus and generating the consumed HCO(3)(-) by secreting protons (H(+)) into the urine (renal acidification). Sodium-proton exchangers (NHEs) are ubiquitous transmembrane proteins mediating the countertransport of Na(+) and H(+) across lipid bilayers. In mammals, NHEs participate in the regulation of cell pH, volume, and intracellular sodium concentration, as well as in transepithelial ion transport. Five of the 10 isoforms (NHE1-4 and NHE8) are expressed at the plasma membrane of renal epithelial cells. The best-studied isoform for acid-base homeostasis is NHE3, which mediates both HCO(3)(-) absorption and H(+) excretion in the renal tubule. This article reviews some important aspects of NHEs in the kidney, with special emphasis on the role of renal NHE3 in the maintenance of acid-base balance.

  6. Na+/H+ Exchangers in Renal Regulation of Acid-Base Balance

    PubMed Central

    Bobulescu, I. Alexandru; Moe, Orson W.

    2010-01-01

    The kidney plays key roles in extracellular fluid pH homeostasis by reclaiming bicarbonate (HCO3−) filtered at the glomerulus and generating the consumed HCO3− by secreting protons (H+) into the urine (renal acidification). Sodium-proton exchangers (NHEs) are ubiquitous transmembrane proteins mediating the countertransport of Na+ and H+ across lipid bilayers. In mammals, NHEs participate in the regulation of cell pH, volume, and intracellular sodium concentration, as well as in transepithelial ion transport. Five of the 10 isoforms (NHE1-4 and NHE8) are expressed at the plasma membrane of renal epithelial cells. The best-studied isoform for acid-base homeostasis is NHE3, which mediates both HCO3− absorption and H+ excretion in the renal tubule. This article reviews some important aspects of NHEs in the kidney, with special emphasis on the role of renal NHE3 in the maintenance of acid-base balance. PMID:17071327

  7. Spiral wound valve-regulated lead-acid batteries for hybrid vehicles

    NASA Astrophysics Data System (ADS)

    Soria, M. L.; Trinidad, F.; Lacadena, J. M.; Valenciano, J.; Arce, G.

    Future vehicle applications require the development of reliable and long life batteries operating under high-rate partial-state-of-charge (HRPSoC) working conditions. This paper updates work carried out to develop spiral wound valve-regulated lead-acid (VRLA) batteries for vehicles with different hybridisation degrees, ranging from stop-start to mild hybrid applications. Former work on design optimisation and active material formulations has been implemented in two spiral wound VRLA batteries, rated 12 V 50 Ah and 6 V 24 Ah, and these two products are currently being tested both in benches and in vehicles with different hybridisation degrees within a demonstration project funded by the Advanced Lead Acid Battery Consortium and in collaboration with several European vehicle and electrical component manufacturers.

  8. Arachidonic Acid Metabolism Regulates Escherichia coli Penetration of the Blood-Brain Barrier▿

    PubMed Central

    Zhu, Longkun; Maruvada, Ravi; Sapirstein, Adam; Malik, Kafait U.; Peters-Golden, Marc; Kim, Kwang Sik

    2010-01-01

    Escherichia coli K1 meningitis occurs following penetration of the blood-brain barrier, but the underlying mechanisms involved in E. coli penetration of the blood-brain barrier remain incompletely understood. We have previously shown that host cytosolic phospholipase A2α (cPLA2α) contributes to E. coli invasion of human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier, but the underlying mechanisms remain unclear. cPLA2α selectively liberates arachidonic acid from membrane phospholipids. Here, we provide the first direct evidence that host 5-lipoxygenase and lipoxygenase products of arachidonic acid, cysteinyl leukotrienes (LTs), contribute to E. coli K1 invasion of HBMEC and penetration into the brain, and their contributions involve protein kinase C alpha (PKCα). These findings demonstrate that arachidonic acid metabolism regulates E. coli penetration of the blood-brain barrier, and studies are needed to further elucidate the mechanisms involved with metabolic products of arachidonic acid for their contribution to E. coli invasion of the blood-brain barrier. PMID:20696828

  9. α-Ketoglutarate regulates acid-base balance through an intrarenal paracrine mechanism

    PubMed Central

    Tokonami, Natsuko; Morla, Luciana; Centeno, Gabriel; Mordasini, David; Ramakrishnan, Suresh Krishna; Nikolaeva, Svetlana; Wagner, Carsten A.; Bonny, Olivier; Houillier, Pascal; Doucet, Alain; Firsov, Dmitri

    2013-01-01

    Paracrine communication between different parts of the renal tubule is increasingly recognized as an important determinant of renal function. Previous studies have shown that changes in dietary acid-base load can reverse the direction of apical α-ketoglutarate (αKG) transport in the proximal tubule and Henle’s loop from reabsorption (acid load) to secretion (base load). Here we show that the resulting changes in the luminal concentrations of αKG are sensed by the αKG receptor OXGR1 expressed in the type B and non-A–non-B intercalated cells of the connecting tubule (CNT) and the cortical collecting duct (CCD). The addition of 1 mM αKG to the tubular lumen strongly stimulated Cl–-dependent HCO3– secretion and electroneutral transepithelial NaCl reabsorption in microperfused CCDs of wild-type mice but not Oxgr1–/– mice. Analysis of alkali-loaded mice revealed a significantly reduced ability of Oxgr1–/– mice to maintain acid-base balance. Collectively, these results demonstrate that OXGR1 is involved in the adaptive regulation of HCO3– secretion and NaCl reabsorption in the CNT/CCD under acid-base stress and establish αKG as a paracrine mediator involved in the functional coordination of the proximal and the distal parts of the renal tubule. PMID:23934124

  10. Alpha-lipoic acid reduces body weight and regulates triglycerides in obese patients with diabetes mellitus.

    PubMed

    Okanović, Azra; Prnjavorac, Besim; Jusufović, Edin; Sejdinović, Rifat

    2015-08-01

    To determine an influence of alpha-lipoic acid to reduction of body weight and regulation of total cholesterol concentration, triglycerides and glucose serum levels in obese patients with diabetes mellitus type 2. A prospective study includes two groups of obese patients with diabetes mellitus and signs of peripheral polyneuropathia: examined group (30 patients; 15 females and 15 males), and control group (30 patients; 12 females and 18 males). All were treated with metformin (850-1700 mg/day). Examined patients were additionally treated with alpha-lipoic acid 600 mg/day during 20 weeks. Body mass index and concentrations of total cholesterol, triglycerides and glucose in serum were compared before and after the treatment. The group treated with 600 mg alpha-lipoic acid lost significantly more weight, and had lower triglyceride level than the control group. There were no significant differences in total cholesterol and glucose serum levels between the groups. Alpha-lipoic acid of 600 mg/day treatment have influenced weight and triglycerides loss in obese patients with diabetes mellitus type 2. It should be considered as an important additive therapy in obese patients with diabetes mellitus type 2. Copyright© by the Medical Assotiation of Zenica-Doboj Canton.

  11. Acid sphingomyelinase activity is regulated by membrane lipids and facilitates cholesterol transfer by NPC2[S

    PubMed Central

    Oninla, Vincent O.; Breiden, Bernadette; Babalola, Jonathan O.; Sandhoff, Konrad

    2014-01-01

    During endocytosis, membrane components move to intraluminal vesicles of the endolysosomal compartment for digestion. At the late endosomes, cholesterol is sorted out mainly by two sterol-binding proteins, Niemann-Pick protein type C (NPC)1 and NPC2. To study the NPC2-mediated intervesicular cholesterol transfer, we developed a liposomal assay system. (Abdul-Hammed, M., B. Breiden, M. A. Adebayo, J. O. Babalola, G. Schwarzmann, and K. Sandhoff. 2010. Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion. J. Lipid Res. 51: 1747–1760.) Anionic lipids stimulate cholesterol transfer between liposomes while SM inhibits it, even in the presence of anionic bis(monoacylglycero)phosphate (BMP). Preincubation of vesicles containing SM with acid sphingomyelinase (ASM) (SM phosphodiesterase, EC 3.1.4.12) results in hydrolysis of SM to ceramide (Cer), which enhances cholesterol transfer. Besides SM, ASM also cleaves liposomal phosphatidylcholine. Anionic phospholipids derived from the plasma membrane (phosphatidylglycerol and phosphatidic acid) stimulate SM and phosphatidylcholine hydrolysis by ASM more effectively than BMP, which is generated during endocytosis. ASM-mediated hydrolysis of liposomal SM was also stimulated by incorporation of diacylglycerol (DAG), Cer, and free fatty acids into the liposomal membranes. Conversely, phosphatidylcholine hydrolysis was inhibited by incorporation of cholesterol, Cer, DAG, monoacylglycerol, and fatty acids. Our data suggest that SM degradation by ASM is required for physiological secretion of cholesterol from the late endosomal compartment, and is a key regulator of endolysosomal lipid digestion. PMID:25339683

  12. The role of membrane fatty-acid transporters in regulating skeletal muscle substrate use during exercise.

    PubMed

    Pelsers, Maurice M A L; Stellingwerff, Trent; van Loon, Luc J C

    2008-01-01

    While endogenous carbohydrates form the main substrate source during high-intensity exercise, long-chain fatty acids (LCFA) represent the main substrate source during more prolonged low- to moderate-intensity exercise. Adipose tissue lipolysis is responsible for the supply of LCFA to the contracting muscle. Once taken up by skeletal muscle tissue, LCFA can either serve as a substrate for oxidative phosphorylation or can be directed towards esterification into triacylglycerol. Myocellular uptake of LCFA comprises a complex and incompletely understood process. Although LCFA can enter the cell via passive diffusion, more recent reports indicate that LCFA uptake is tightly regulated by plasma membrane-located transport proteins (fatty acid translocase [FAT/CD36], plasmalemmal-located fatty acid binding protein [FABPpm] and fatty acid transport protein [FATP]). Depending on cardiac and skeletal muscle energy demands, some of these LCFA transporters can translocate rapidly from intracellular pools to the plasma membrane to allow greater LCFA uptake. This translocation process can be induced by insulin and/or muscle contraction. However, the precise signalling pathways responsible for activating the translocation machinery remain to be elucidated. This article will provide an overview on the effects of diet, acute exercise and exercise training on the expression and/or translocation of the various LCFA transporters in skeletal muscle tissue (FAT/CD36, FABPpm, FATP).

  13. Hydroxyeicosatetraenoic acids released through the cytochrome P-450 pathway regulate 3T6 fibroblast growth.

    PubMed

    Nieves, Diana; Moreno, Juan José

    2006-12-01

    Eicosanoids participate in the regulation of cellular proliferation. Thus, we observed that prostaglandin E(2) interaction with membrane receptors is involved in the control of 3T6 fibroblast growth induced by serum. However, our results suggested that another arachidonic acid pathway might be implicated in these events. Our results show that 3T6 fibroblasts synthesized hydroxyeicosatetraenoic acids (HETEs) such as 12-HETE through the cytochrome P-450 (CYP450) pathway. However, 3T6 fibroblasts did not produce leukotriene B(4) (LTB(4)), and lipoxygenase inhibitors and LT antagonists failed to inhibit 3T6 fibroblast growth induced by FBS. In contrast, we observed that CYP450 inhibitors such as SKF-525A, 17-octadecynoic acid, 1-aminobenzotriazole, and 6-(2-propargyloxyphenyl)hexanoic acid reduced 12(S)-HETE levels, 3T6 fibroblast growth, and DNA synthesis induced by FBS. The impairment of DNA synthesis and 3T6 fibroblast growth induced by SKF-525A were reversed by exogenous addition of HETEs. Moreover, we report that 5-HETE, 12(S)-HETE, and 15(S)-HETE are mitogenic on 3T6 fibroblast in the absence of another growth factor, and this effect was dependent on the activation of the phosphatidylinositol-3-kinase pathway. In conclusion, our results show that HETEs, probably produced by CYP450, are involved in the control of 3T6 fibroblast growth.

  14. Conserved regulators of Rag GTPases orchestrate amino acid-dependent TORC1 signaling

    PubMed Central

    Powis, Katie; De Virgilio, Claudio

    2016-01-01

    The highly conserved target of rapamycin complex 1 (TORC1) is the central component of a signaling network that couples a vast range of internal and external stimuli to cell growth, proliferation and metabolism. TORC1 deregulation is associated with a number of human pathologies, including many cancers and metabolic disorders, underscoring its importance in cellular and organismal growth control. The activity of TORC1 is modulated by multiple inputs; however, the presence of amino acids is a stimulus that is essential for its activation. Amino acid sufficiency is communicated to TORC1 via the highly conserved family of Rag GTPases, which assemble as heterodimeric complexes on lysosomal/vacuolar membranes and are regulated by their guanine nucleotide loading status. Studies in yeast, fly and mammalian model systems have revealed a multitude of conserved Rag GTPase modulators, which have greatly expanded our understanding of amino acid sensing by TORC1. Here we review the major known modulators of the Rag GTPases, focusing on recent mechanistic insights that highlight the evolutionary conservation and divergence of amino acid signaling to TORC1. PMID:27462445

  15. The heparan and heparin metabolism pathway is involved in regulation of fatty acid composition.

    PubMed

    Jiang, Zhihua; Michal, Jennifer J; Wu, Xiao-Lin; Pan, Zengxiang; MacNeil, Michael D

    2011-01-01

    Six genes involved in the heparan sulfate and heparin metabolism pathway, DSEL (dermatan sulfate epimerase-like), EXTL1 (exostoses (multiple)-like 1), HS6ST1 (heparan sulfate 6-O-sulfotransferase 1), HS6ST3 (heparan sulfate 6-O-sulfotransferase 3), NDST3 (N-deacetylase/N-sulfotransferase (heparan glucosaminyl) 3), and SULT1A1 (sulfotransferase family, cytosolic, 1A, phenol-preferring, member 1), were investigated for their associations with muscle lipid composition using cattle as a model organism. Nineteen single nucleotide polymorphisms (SNPs)/multiple nucleotide length polymorphisms (MNLPs) were identified in five of these six genes. Six of these mutations were then genotyped on 246 Wagyu x Limousin F(2) animals, which were measured for 5 carcass, 6 eating quality and 8 fatty acid composition traits. Association analysis revealed that DSEL, EXTL1 and HS6ST1 significantly affected two stearoyl-CoA desaturase activity indices, the amount of conjugated linoleic acid (CLA), and the relative amount of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in skeletal muscle (P<0.05). In particular, HS6ST1 joined our previously reported SCD1 and UQCRC1 genes to form a three gene network for one of the stearoyl-CoA desaturase activity indices. These results provide evidence that genes involved in heparan sulfate and heparin metabolism are also involved in regulation of lipid metabolism in bovine muscle. Whether the SNPs affected heparan sulfate proteoglycan structure is unknown and warrants further investigation.

  16. The effect of fatty acids on the regulation of pyruvate dehydrogenase in perfused rat liver.

    PubMed

    Scholz, R; Olson, M S; Schwab, A J; Schwabe, U; Noell, C; Braun, W

    1978-05-16

    The effect of fatty acids on the rate of pyruvate decarboxylation was studied in perfused livers from fed rats. The production of 14CO2 from infused [1-14C]pyruvate was employed as a monitor of the flux through the pyruvate dehydrogenase reaction. A correction for other decarboxylation reactions was made using kinetic analyses. Fatty acid (octanoate or oleate) infusion caused a stimulation of pyruvate decarboxylation at pyruvate concentrations in the perfusate below 1 mM (up to 3-fold at 0.05 mM pyruvate) but decreased the rate to one-third of control rates at pyruvate concentrations near 5 mM. These effects were half-maximal at fatty acid concentrations below 0.1 mM. Infusion of 3-hydroxybutyrate also caused a marked stimulation of pyruvate decarboxylation at low pyruvate concentrations. The data suggest that the mechanism by which fatty acids stimulate the flux through the pyruvate dehydrogenase reaction in perfused liver at low (limiting) pyruvate concentrations involves an acceleration of pyruvate transport into the mitochondrial compartment due to an exchange with acetoacetate. Furthermore, it is proposed that a relationship exists between ketogenesis and the regulation of pyruvate oxidation at pyruvate concentrations approximating conditions in vivo.

  17. Basic Aspects of Tumor Cell Fatty Acid-Regulated Signaling and Transcription Factors

    PubMed Central

    Comba, Andrea; Lin, Yi-Hui; Eynard, Aldo Renato; Valentich, Mirta Ana; Fernandez-Zapico, Martin Ernesto; Pasqualini, Marìa Eugenia

    2012-01-01

    This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids (PUFAs) of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases (LOXs), cyclooxygenases (COXs), and cytochrome P-450 (CYP-450), seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator–activated receptors (PPARs) or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C [PKC]) and other transcription factors (nuclear factor kappa B [NFκB] and sterol regulatory element binding protein [SREBP]). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer, and provide insight into the development of new therapeutic strategies for a better management of whole-body lipid metabolism. PMID:22048864

  18. Glutamic Acid Residues in HIV-1 p6 Regulate Virus Budding and Membrane Association of Gag.

    PubMed

    Friedrich, Melanie; Setz, Christian; Hahn, Friedrich; Matthaei, Alina; Fraedrich, Kirsten; Rauch, Pia; Henklein, Petra; Traxdorf, Maximilian; Fossen, Torgils; Schubert, Ulrich

    2016-04-25

    The HIV-1 Gag p6 protein regulates the final abscission step of nascent virions from the cell membrane by the action of its two late (L-) domains, which recruit Tsg101 and ALIX, components of the ESCRT system. Even though p6 consists of only 52 amino acids, it is encoded by one of the most polymorphic regions of the HIV-1 gag gene and undergoes various posttranslational modifications including sumoylation, ubiquitination, and phosphorylation. In addition, it mediates the incorporation of the HIV-1 accessory protein Vpr into budding virions. Despite its small size, p6 exhibits an unusually high charge density. In this study, we show that mutation of the conserved glutamic acids within p6 increases the membrane association of Pr55 Gag followed by enhanced polyubiquitination and MHC-I antigen presentation of Gag-derived epitopes, possibly due to prolonged exposure to membrane bound E3 ligases. The replication capacity of the total glutamic acid mutant E0A was almost completely impaired, which was accompanied by defective virus release that could not be rescued by ALIX overexpression. Altogether, our data indicate that the glutamic acids within p6 contribute to the late steps of viral replication and may contribute to the interaction of Gag with the plasma membrane.

  19. Regulation of GABA-modulin phosphorylation and GABA receptor binding by excitatory amino acids

    SciTech Connect

    Vaccarino, F.; Guidotti, A.

    1987-05-01

    Primary cultures of cerebellar granule cells phosphorylate numerous proteins including GABA-modulin (GM), which is a putative allosteric modulator of GABA receptors. Cell depolarization and treatment with dicarboxylic excitatory amino acids, which activate PI turnover, Ca/sup 2 +/ influx and guanylate cyclase in granule cells increase the phosphorylation of specific proteins. To determine GM phosphorylation by endogenous protein kinases in living granule cell cultures, GM was isolated by immunoprecipitation and reverse-phase HPLC. High K/sup +/, veratridine, glutamate and NMDA treatment stimulated GM phosphorylation over 2-fold. This increase was abolished by the absence of extracellular Ca/sup 2 +/ and was antagonized by Mg/sup 2 +/ ions and by AVP. The excitatory amino acid action was mimicked by phorbol esters but not by forskolin or by cGMP, and thus may be mediated by an activation of protein kinase C (PKC). Moreover, excitatory amino acids increase /sup 3/H-labelled phorbol ester binding sites in granule cell membrane. The same cultures, treated with glutamate or kainate, showed a 50-fold greater efficacy of muscimol for the stimulation of benzodiazepine (BZ) binding. These data-suggest that excitatory amino acid stimulation of neurons triggers PKC translocation and the activated enzyme phosphorylates GM. The extent of GM phosphorylation may regulate the coupling between GABA and BZ binding sites.

  20. Enhanced pinocembrin production in Escherichia coli by regulating cinnamic acid metabolism

    PubMed Central

    Cao, Weijia; Ma, Weichao; Wang, Xin; Zhang, Bowen; Cao, Xun; Chen, Kequan; Li, Yan; Ouyang, Pingkai

    2016-01-01

    Microbial biosynthesis of pinocembrin is of great interest in the area of drug research and human healthcare. Here we found that the accumulation of the pathway intermediate cinnamic acid adversely affected pinocembrin production. Hence, a stepwise metabolic engineering strategy was carried out aimed at eliminating this pathway bottleneck and increasing pinocembrin production. The screening of gene source and the optimization of gene expression was first employed to regulate the synthetic pathway of cinnamic acid, which showed a 3.53-fold increase in pinocembrin production (7.76 mg/L) occurred with the alleviation of cinnamic acid accumulation in the engineered E. coli. Then, the downstream pathway that consuming cinnamic acid was optimized by the site-directed mutagenesis of chalcone synthase and cofactor engineering. S165M mutant of chalcone synthase could efficiently improve the pinocembrin production, and allowed the product titer of pinocembrin increased to 40.05 mg/L coupled with the malonyl-CoA engineering. With a two-phase pH fermentation strategy, the cultivation of the optimized strain resulted in a final pinocembrin titer of 67.81 mg/L. The results and engineering strategies demonstrated here would hold promise for the titer improvement of other flavonoids. PMID:27586788

  1. De novo amino acid biosynthesis in potato tubers is regulated by sucrose levels.

    PubMed

    Roessner-Tunali, Ute; Urbanczyk-Wochniak, Ewa; Czechowski, Tomasz; Kolbe, Anna; Willmitzer, Lothar; Fernie, Alisdair R

    2003-10-01

    Plant growth and development are strongly dependent on sink-source interactions. In the majority of plants, sucrose (Suc) is the dominant form in which photo-assimilate is transported from source to sinks. Although the effects of Suc on photosynthetic metabolism have been intensively studied, the effect of Suc supply on metabolism in sink organs has received relatively little attention. For this reason, we performed a detailed characterization of the metabolism of potato (Solanum tuberosum) plants in which the Suc supply to the tuber was restricted by genetic or environmental perturbation. These characterizations revealed a clear inverse relationship between the levels of Suc and free amino acids. When data obtained from this study were considered alongside our previous work, a negative correlation between tuber Suc and amino acid content became apparent. Analysis of the transcript levels of key enzymes involved in amino acid biosynthesis revealed that several of these were increased under these conditions. Taken together, these data strongly suggest that Suc regulates amino acid biosynthesis in storage tissues such as potato tubers, most probably at the level of transcription.

  2. Regulation of laminin and entactin mRNA levels by retinoic acid and dibutyryl cyclic AMP

    SciTech Connect

    Durkin, M.E.; Phillips, S.L.; Carlin, B.E.; Merlie, J.P.; Chung, A.E.

    1986-05-01

    Retinoic acid and dibutyryl cAMP induced F9 embryonal carcinoma cells to differentiate to parietal endoderm; the morphological changes were accompanied by the increased synthesis of the basement membrane glycoproteins laminin and entactin. cDNA clones have been isolated for the A (400 kD), B1 (220 kD), and B2 (205 kD) chains of laminin. Northern blot analysis indicated that the A, B1, and B2 chains were encoded by RNA species of 9.8, 6.0, and 8.0 kb, respectively. The kinetics of induction of the laminin mRNAs were studied by dot-blotting dilutions of RNA extracted from F9 cells cultured in retinoic acid and dibutyryl cAMP for increasing amounts of time and hybridizing to /sup 32/P-labeled recombinant plasmids. Very low levels of the A and B chain RNAs were found in uninduced cells, and a large increase occurred between 48 and 72 hr of growth in retinoic acid and dibutyryl cAMP. A cDNA clone was also obtained for entactin, a 150 kD glycoprotein that forms a complex with laminin. Retinoic acid and dibutyryl cAMP treatment also increased the amount of entactin RNA in F9 cells. These results suggested that a common mechanism may exist for the coordinate regulation of the 4 basement membrane protein genes during differentiation.

  3. Glutamic Acid Residues in HIV-1 p6 Regulate Virus Budding and Membrane Association of Gag

    PubMed Central

    Friedrich, Melanie; Setz, Christian; Hahn, Friedrich; Matthaei, Alina; Fraedrich, Kirsten; Rauch, Pia; Henklein, Petra; Traxdorf, Maximilian; Fossen, Torgils; Schubert, Ulrich

    2016-01-01

    The HIV-1 Gag p6 protein regulates the final abscission step of nascent virions from the cell membrane by the action of its two late (l-) domains, which recruit Tsg101 and ALIX, components of the ESCRT system. Even though p6 consists of only 52 amino acids, it is encoded by one of the most polymorphic regions of the HIV-1 gag gene and undergoes various posttranslational modifications including sumoylation, ubiquitination, and phosphorylation. In addition, it mediates the incorporation of the HIV-1 accessory protein Vpr into budding virions. Despite its small size, p6 exhibits an unusually high charge density. In this study, we show that mutation of the conserved glutamic acids within p6 increases the membrane association of Pr55 Gag followed by enhanced polyubiquitination and MHC-I antigen presentation of Gag-derived epitopes, possibly due to prolonged exposure to membrane bound E3 ligases. The replication capacity of the total glutamic acid mutant E0A was almost completely impaired, which was accompanied by defective virus release that could not be rescued by ALIX overexpression. Altogether, our data indicate that the glutamic acids within p6 contribute to the late steps of viral replication and may contribute to the interaction of Gag with the plasma membrane. PMID:27120610

  4. Drosophila Fatty Acid Transport Protein Regulates Rhodopsin-1 Metabolism and Is Required for Photoreceptor Neuron Survival

    PubMed Central

    Dourlen, Pierre; Bertin, Benjamin; Chatelain, Gilles; Robin, Marion; Napoletano, Francesco; Roux, Michel J.; Mollereau, Bertrand

    2012-01-01

    Tight regulation of the visual response is essential for photoreceptor function and survival. Visual response dysregulation often leads to photoreceptor cell degeneration, but the causes of such cell death are not well understood. In this study, we investigated a fatty acid transport protein (fatp) null mutation that caused adult-onset and progressive photoreceptor cell death. Consistent with fatp having a role in the retina, we showed that fatp is expressed in adult photoreceptors and accessory cells and that its re-expression in photoreceptors rescued photoreceptor viability in fatp mutants. The visual response in young fatp-mutant flies was abnormal with elevated electroretinogram amplitudes associated with high levels of Rhodopsin-1 (Rh1). Reducing Rh1 levels in rh1 mutants or depriving flies of vitamin A rescued photoreceptor cell death in fatp mutant flies. Our results indicate that fatp promotes photoreceptor survival by regulating Rh1 abundance. PMID:22844251

  5. Regulators of PP2C phosphatase activity function as abscisic acid sensors.

    PubMed

    Ma, Yue; Szostkiewicz, Izabela; Korte, Arthur; Moes, Danièle; Yang, Yi; Christmann, Alexander; Grill, Erwin

    2009-05-22

    The plant hormone abscisic acid (ABA) acts as a developmental signal and as an integrator of environmental cues such as drought and cold. Key players in ABA signal transduction include the type 2C protein phosphatases (PP2Cs) ABI1 and ABI2, which act by negatively regulating ABA responses. In this study, we identify interactors of ABI1 and ABI2 which we have named regulatory components of ABA receptor (RCARs). In Arabidopsis, RCARs belong to a family with 14 members that share structural similarity with class 10 pathogen-related proteins. RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta. Other RCARs also mediated ABA-dependent regulation of ABI1 and ABI2, consistent with a combinatorial assembly of receptor complexes.

  6. New roles for Smad signaling and phosphatidic acid in the regulation of skeletal muscle mass

    PubMed Central

    Goodman, Craig A.

    2014-01-01

    Skeletal muscle is essential for normal bodily function and the loss of skeletal muscle (i.e. muscle atrophy/wasting) can have a major impact on mobility, whole-body metabolism, disease resistance, and quality of life. Thus, there is a clear need for the development of therapies that can prevent the loss, or increase, of skeletal muscle mass. However, in order to develop such therapies, we will first have to develop a thorough understanding of the molecular mechanisms that regulate muscle mass. Fortunately, our knowledge is rapidly advancing, and in this review, we will summarize recent studies that have expanded our understanding of the roles that Smad signaling and the synthesis of phosphatidic acid play in the regulation of skeletal muscle mass. PMID:24765525

  7. New roles for Smad signaling and phosphatidic acid in the regulation of skeletal muscle mass.

    PubMed

    Goodman, Craig A; Hornberger, Troy A

    2014-01-01

    Skeletal muscle is essential for normal bodily function and the loss of skeletal muscle (i.e. muscle atrophy/wasting) can have a major impact on mobility, whole-body metabolism, disease resistance, and quality of life. Thus, there is a clear need for the development of therapies that can prevent the loss, or increase, of skeletal muscle mass. However, in order to develop such therapies, we will first have to develop a thorough understanding of the molecular mechanisms that regulate muscle mass. Fortunately, our knowledge is rapidly advancing, and in this review, we will summarize recent studies that have expanded our understanding of the roles that Smad signaling and the synthesis of phosphatidic acid play in the regulation of skeletal muscle mass.

  8. Microbiota regulate intestinal absorption and metabolism of fatty acids in the zebrafish.

    PubMed

    Semova, Ivana; Carten, Juliana D; Stombaugh, Jesse; Mackey, Lantz C; Knight, Rob; Farber, Steven A; Rawls, John F

    2012-09-13

    Regulation of intestinal dietary fat absorption is critical to maintaining energy balance. While intestinal microbiota clearly impact the host's energy balance, their role in intestinal absorption and extraintestinal metabolism of dietary fat is less clear. Using in vivo imaging of fluorescent fatty acid (FA) analogs delivered to gnotobiotic zebrafish hosts, we reveal that microbiota stimulate FA uptake and lipid droplet (LD) formation in the intestinal epithelium and liver. Microbiota increase epithelial LD number in a diet-dependent manner. The presence of food led to the intestinal enrichment of bacteria from the phylum Firmicutes. Diet-enriched Firmicutes and their products were sufficient to increase epithelial LD number, whereas LD size was increased by other bacterial types. Thus, different members of the intestinal microbiota promote FA absorption via distinct mechanisms. Diet-induced alterations in microbiota composition might influence fat absorption, providing mechanistic insight into how microbiota-diet interactions regulate host energy balance. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Microbiota regulate intestinal absorption and metabolism of fatty acids in the zebrafish

    PubMed Central

    Semova, Ivana; Carten, Juliana D.; Stombaugh, Jesse; Mackey, Lantz C.; Knight, Rob; Farber, Steven A.; Rawls, John F.

    2012-01-01

    SUMMARY Regulation of intestinal dietary fat absorption is critical to maintaining energy balance. While intestinal microbiota clearly impact the host’s energy balance, their role in intestinal absorption and extra-intestinal metabolism of dietary fat is less clear. Using in vivo imaging of fluorescent fatty acid (FA) analogs delivered to gnotobiotic zebrafish hosts, we reveal that microbiota stimulate FA uptake and lipid droplet (LD) formation in the intestinal epithelium and liver. Microbiota increase epithelial LD number in a diet-dependent manner. The presence of food led to the intestinal enrichment of bacteria from the phylum Firmicutes. Diet-enriched Firmicutes and their products were sufficient to increase epithelial LD number, whereas LD size was increased by other bacterial types. Thus, different members of the intestinal microbiota promote FA absorption via distinct mechanisms. Diet-induced alterations in microbiota composition might influence fat absorption, providing mechanistic insight into how microbiota-diet interactions regulate host energy balance. PMID:22980325

  10. Regulation of water, salinity, and cold stress responses by salicylic acid.

    PubMed

    Miura, Kenji; Tada, Yasuomi

    2014-01-01

    Salicylic acid (SA) is a naturally occurring phenolic compound. SA plays an important role in the regulation of plant growth, development, ripening, and defense responses. The role of SA in the plant-pathogen relationship has been extensively investigated. In addition to defense responses, SA plays an important role in the response to abiotic stresses, including drought, low temperature, and salinity stresses. It has been suggested that SA has great agronomic potential to improve the stress tolerance of agriculturally important crops. However, the utility of SA is dependent on the concentration of the applied SA, the mode of application, and the state of the plants (e.g., developmental stage and acclimation). Generally, low concentrations of applied SA alleviate the sensitivity to abiotic stresses, and high concentrations of applied induce high levels of oxidative stress, leading to a decreased tolerance to abiotic stresses. In this article, the effects of SA on the water stress responses and regulation of stomatal closure are reviewed.

  11. Reliability of valve-regulated lead-acid batteries for stationary applications.

    SciTech Connect

    De Anda, Mindi Farber; Butler, Paul Charles; Miller, Jennifer L; Moseley, Patrick T.

    2004-03-01

    A survey has been carried out to quantify the performance and life of over 700,000 valve-regulated lead-acid (VRLA) cells, which have been or are being used in stationary applications across the United States. The findings derived from this study have not identified any fundamental flaws of VRLA battery technology. There is evidence that some cell designs are more successful in float duty than others. A significant number of the VRLA cells covered by the survey were found to have provided satisfactory performance.

  12. Development of 36-V valve-regulated lead-acid battery

    NASA Astrophysics Data System (ADS)

    Ohmae, T.; Hayashi, T.; Inoue, N.

    A 36-V valve-regulated lead-acid (VRLA) battery used in a 42-V power system has been developed for the Toyota Hybrid System-Mild (THS-M) vehicle to meet the large electrical power requirements of hybrid electric vehicles (HEVs) and the increasing power demands on modern automobile electrical systems. The battery has a longer cycle-life in HEV use through the application of ultra high-density active-material and an anti-corrosive grid alloy for the positive plates, special additives for the negative plates, and absorbent glass mat with less contraction for the separators.

  13. Regulation of c-myb expression in human neuroblastoma cells during retinoic acid-induced differentiation.

    PubMed Central

    Thiele, C J; Cohen, P S; Israel, M A

    1988-01-01

    We detected expression of the c-myb proto-oncogene, which was initially thought to be expressed in a tissue-specific manner in cells of hematopoietic lineage, in human tissues of neuronal origin. Since the level of c-myb expression declined during fetal development, we studied the regulation of its expression in human neuroblastoma cell lines induced to differentiate by retinoic acid. The expression of c-myb declined during the maturation of neuroblastoma cells, and this change was mediated by a decrease in c-myb transcription. Images PMID:3380093

  14. Role of bile acids in the regulation of the metabolic pathways

    PubMed Central

    Taoka, Hiroki; Yokoyama, Yoko; Morimoto, Kohkichi; Kitamura, Naho; Tanigaki, Tatsuya; Takashina, Yoko; Tsubota, Kazuo; Watanabe, Mitsuhiro

    2016-01-01

    Recent studies have revealed that bile acids (BAs) are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions. Some major signaling pathways involving the nuclear BAs receptor farnesoid X receptor and the G protein-coupled BAs receptor TGR5/M-BAR have been identified to be the targets of BAs. BAs regulate their own homeostasis via signaling pathways. BAs also affect diverse metabolic pathways including glucose metabolism, lipid metabolism and energy expenditure. This paper suggests the mechanism of controlling metabolism via BA signaling and demonstrates that BA signaling is an attractive therapeutic target of the metabolic syndrome. PMID:27433295

  15. Characterization and Regulation of the Amino Acid Transporter SNAT2 in the Small Intestine of Piglets

    PubMed Central

    Tan, Bie; Wang, Jing; Kong, Xiangfeng; Guan, Guiping; Li, Fengna; Yin, Yulong

    2015-01-01

    The sodium-dependent neutral amino acid transporter 2 (SNAT2), which has dual transport/receptor functions, is well documented in eukaryotes and some mammalian systems, but has not yet been verified in piglets. The objective of this study was to investigate the characteristics and regulation of SNAT2 in the small intestine of piglets. The 1,521-bp porcine full cDNA sequence of SNAT2 (KC769999) from the small intestine of piglets was cloned. The open reading frame of cDNA encodes 506 deduced amino acid residues with a calculated molecular mass of 56.08 kDa and an isoelectric point (pI) of 7.16. Sequence alignment and phylogenetic analysis revealed that SNAT2 is highly evolutionarily conserved in mammals. SNAT2 mRNA can be detected in the duodenum, jejunum and ileum by real-time quantitative PCR. During the suckling period from days 1 to 21, the duodenum had the highest abundance of SNAT2 mRNA among the three segments of the small intestine. There was a significant decrease in the expression of SNAT2 mRNA in the duodenal and jejunal mucosa and in the expression of SNAT2 protein in the jejunal and ileal mucosa on day 1 after weaning (P < 0.05). Studies with enterocytes in vitro showed that amino acid starvation and supplementation with glutamate, arginine or leucine enhanced, while supplementation with glutamine reduced, SNAT2 mRNA expression (P < 0.05). These results regarding the characteristics and regulation of SNAT2 should help to provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine. PMID:26107628

  16. ATP binding cassette modulators control abscisic acid-regulated slow anion channels in guard cells

    PubMed Central

    Leonhardt, N; Vavasseur, A; Forestier, C

    1999-01-01

    In animal cells, ATP binding cassette (ABC) proteins are a large family of transporters that includes the sulfonylurea receptor and the cystic fibrosis transmembrane conductance regulator (CFTR). These two ABC proteins possess an ion channel activity and bind specific sulfonylureas, such as glibenclamide, but homologs have not been identified in plant cells. We recently have shown that there is an ABC protein in guard cells that is involved in the control of stomatal movements and guard cell outward K+ current. Because the CFTR, a chloride channel, is sensitive to glibenclamide and able to interact with K+ channels, we investigated its presence in guard cells. Potent CFTR inhibitors, such as glibenclamide and diphenylamine-2-carboxylic acid, triggered stomatal opening in darkness. The guard cell protoplast slow anion current that was recorded using the whole-cell patch-clamp technique was inhibited rapidly by glibenclamide in a dose-dependent manner; the concentration producing half-maximum inhibition was at 3 &mgr;M. Potassium channel openers, which bind to and act through the sulfonylurea receptor in animal cells, completely suppressed the stomatal opening induced by glibenclamide and recovered the glibenclamide-inhibited slow anion current. Abscisic acid is known to regulate slow anion channels and in our study was able to relieve glibenclamide inhibition of slow anion current. Moreover, in epidermal strip bioassays, the stomatal closure triggered by Ca2+ or abscisic acid was reversed by glibenclamide. These results suggest that the slow anion channel is an ABC protein or is tightly controlled by such a protein that interacts with the abscisic acid signal transduction pathway in guard cells. PMID:10368184

  17. Down-regulation of cyclooxygenase-2 (COX-2) by cannabidiolic acid in human breast cancer cells.

    PubMed

    Takeda, Shuso; Okazaki, Hiroyuki; Ikeda, Eriko; Abe, Satomi; Yoshioka, Yasushi; Watanabe, Kazuhito; Aramaki, Hironori

    2014-01-01

    Metastases are known to be responsible for approximately 90% of breast cancer-related deaths. Cyclooxygenase-2 (COX-2) is involved not only in inflammatory processes, but also in the metastasis of cancer cells; it is expressed in 40% of human invasive breast cancers. To comprehensively analyze the effects of cannabidiolic acid (CBDA), a selective COX-2 inhibitor found in the fiber-type cannabis plant (Takeda et al., 2008), on COX-2 expression and the genes involved in metastasis, we performed a DNA microarray analysis of human breast cancer MDA-MB-231 cells, which are invasive breast cancer cells that express high levels of COX-2, treated with CBDA for 48 hr at 25 µM. The results obtained revealed that COX-2 and Id-1, a positive regulator of breast cancer metastasis, were down-regulated (0.19-fold and 0.52-fold, respectively), while SHARP1 (or BHLHE41), a suppressor of breast cancer metastasis, was up-regulated (1.72-fold) and CHIP (or STUB1) was unaffected (1.03-fold). These changes were confirmed by real-time RT-PCR analyses. Taken together, the results obtained here demonstrated that i) CBDA had dual inhibitory effects on COX-2 through down-regulation and enzyme inhibition, and ii) CBDA may possess the ability to suppress genes that are positively involved in the metastasis of cancer cells in vitro.

  18. A Nuclear Factor Regulates Abscisic Acid Responses in Arabidopsis1[W][OA

    PubMed Central

    Kim, Min Jung; Shin, Ryoung; Schachtman, Daniel P.

    2009-01-01

    Abscisic acid (ABA) is a plant hormone that regulates plant growth as well as stress responses. In this study, we identified and characterized a new Arabidopsis (Arabidopsis thaliana) protein, Nuclear Protein X1 (NPX1), which was up-regulated by stress and treatment with exogenous ABA. Stomatal closure, seed germination, and primary root growth are well-known ABA responses that were less sensitive to ABA in NPX1-overexpressing plants. NPX1-overexpressing plants were more drought sensitive, and the changes in response to drought were due to the altered guard cell sensitivity to ABA in transgenic plants and not to a lack of ABA production. The nuclear localization of NPX1 correlated with changes in the expression of genes involved in ABA biosynthesis and ABA signal transduction. To understand the function of NPX1, we searched for interacting proteins and found that an ABA-inducible NAC transcription factor, TIP, interacted with NPX1. Based on the whole plant phenotypes, we hypothesized that NPX1 acts as a transcriptional repressor, and this was demonstrated in yeast, where we showed that TIP was repressed by NPX1. Our results indicate that the previously unknown protein NPX1 acts as a negative regulator in plant response to changes in environmental conditions through the control of ABA-regulated gene expression. The characterization of this factor enhances our understanding of guard cell function and the mechanisms that plants use to modulate water loss from leaves under drought conditions. PMID:19759343

  19. Regulation of basal and oxidative stress-triggered jasmonic acid-related gene expression by glutathione.

    PubMed

    Han, Yi; Mhamdi, Amna; Chaouch, Sejir; Noctor, Graham

    2013-06-01

    Glutathione is a determinant of cellular redox state with roles in defence and detoxification. Emerging concepts suggest that this compound also has functions in cellular signalling. Here, we report evidence that glutathione plays potentially important roles in setting signalling strength through the jasmonic acid (JA) pathway. Firstly, we show that basal expression of JA-related genes is correlated with leaf glutathione content when the latter is manipulated either genetically or pharmacologically. Secondly, analyses of an oxidative stress signalling mutant, cat2, reveal that up-regulation of the JA pathway triggered by intracellular oxidation requires accompanying glutathione accumulation. Genetically blocking this accumulation in a cat2 cad2 line largely annuls H2 O2 -induced expression of JA-linked genes, and this effect can be rescued by exogenously supplying glutathione. While most attention on glutathione functions in biotic stress responses has been focused on the thiol-regulated protein NPR1, a comparison of JA-linked gene expression in cat2 cad2 and cat2 npr1 double mutants provides evidence that glutathione acts through other components to regulate the response of this pathway to oxidative stress. Our study provides new information implicating glutathione as a factor determining basal JA gene expression and suggests novel glutathione-dependent control points that regulate JA signalling in response to intracellular oxidation.

  20. Somite-Derived Retinoic Acid Regulates Zebrafish Hematopoietic Stem Cell Formation

    PubMed Central

    Pillay, Laura M.; Mackowetzky, Kacey J.; Widen, Sonya A.; Waskiewicz, Andrew Jan

    2016-01-01

    Hematopoietic stem cells (HSCs) are multipotent progenitors that generate all vertebrate adult blood lineages. Recent analyses have highlighted the importance of somite-derived signaling factors in regulating HSC specification and emergence from dorsal aorta hemogenic endothelium. However, these factors remain largely uncharacterized. We provide evidence that the vitamin A derivative retinoic acid (RA) functions as an essential regulator of zebrafish HSC formation. Temporal analyses indicate that RA is required for HSC gene expression prior to dorsal aorta formation, at a time when the predominant RA synthesis enzyme, aldh1a2, is strongly expressed within the paraxial mesoderm and somites. Previous research implicated the Cxcl12 chemokine and Notch signaling pathways in HSC formation. Consequently, to understand how RA regulates HSC gene expression, we surveyed the expression of components of these pathways in RA-depleted zebrafish embryos. During somitogenesis, RA-depleted embryos exhibit altered expression of jam1a and jam2a, which potentiate Notch signaling within nascent endothelial cells. RA-depleted embryos also exhibit a severe reduction in the expression of cxcr4a, the predominant Cxcl12b receptor. Furthermore, pharmacological inhibitors of RA synthesis and Cxcr4 signaling act in concert to reduce HSC formation. Our analyses demonstrate that somite-derived RA functions to regulate components of the Notch and Cxcl12 chemokine signaling pathways during HSC formation. PMID:27861498

  1. VEGF and endothelium-derived retinoic acid regulate lung vascular and alveolar development

    PubMed Central

    Yun, Eun Jun; Lorizio, Walter; Seedorf, Gregory; Abman, Steven H.

    2015-01-01

    Prevention or treatment of lung diseases caused by the failure to form, or destruction of, existing alveoli, as observed in infants with bronchopulmonary dysplasia and adults with emphysema, requires understanding of the molecular mechanisms of alveolar development. In addition to its critical role in gas exchange, the pulmonary circulation also contributes to alveolar morphogenesis and maintenance by the production of paracrine factors, termed “angiocrines,” that impact the development of surrounding tissue. To identify lung angiocrines that contribute to alveolar formation, we disrupted pulmonary vascular development by conditional inactivation of the Vegf-A gene during alveologenesis. This resulted in decreased pulmonary capillary and alveolar development and altered lung elastin and retinoic acid (RA) expression. We determined that RA is produced by pulmonary endothelial cells and regulates pulmonary angiogenesis and elastin synthesis by induction of VEGF-A and fibroblast growth factor (FGF)-18, respectively. Inhibition of RA synthesis in newborn mice decreased FGF-18 and elastin expression and impaired alveolarization. Treatment with RA and vitamin A partially reversed the impaired vascular and alveolar development induced by VEGF inhibition. Thus we identified RA as a lung angiocrine that regulates alveolarization through autocrine regulation of endothelial development and paracrine regulation of elastin synthesis via induction of FGF-18 in mesenchymal cells. PMID:26566904

  2. Separate responses of karyopherins to glucose and amino acid availability regulate nucleocytoplasmic transport

    PubMed Central

    Huang, Hsiao-Yun; Hopper, Anita K.

    2014-01-01

    The importin-β family members (karyopherins) mediate the majority of nucleocytoplasmic transport. Msn5 and Los1, members of the importin-β family, function in tRNA nuclear export. tRNAs move bidirectionally between the nucleus and the cytoplasm. Nuclear tRNA accumulation occurs upon amino acid (aa) or glucose deprivation. To understand the mechanisms regulating tRNA subcellular trafficking, we investigated whether Msn5 and Los1 are regulated in response to nutrient availability. We provide evidence that tRNA subcellular trafficking is regulated by distinct aa-sensitive and glucose-sensitive mechanisms. Subcellular distributions of Msn5 and Los1 are altered upon glucose deprivation but not aa deprivation. Redistribution of tRNA exportins from the nucleus to the cytoplasm likely provides one mechanism for tRNA nuclear distribution upon glucose deprivation. We extended our studies to other members of the importin-β family and found that all tested karyopherins invert their subcellular distributions upon glucose deprivation but not aa deprivation. Glucose availability regulates the subcellular distributions of karyopherins likely due to alteration of the RanGTP gradient since glucose deprivation causes redistribution of Ran. Thus nuclear–cytoplasmic distribution of macromolecules is likely generally altered upon glucose deprivation due to collapse of the RanGTP gradient and redistribution of karyopherins between the nucleus and the cytoplasm. PMID:25057022

  3. All-trans retinoic acid negatively regulates cytotoxic activities of nature killer cell line 92

    SciTech Connect

    Li Ang . E-mail: liang3829@sina.com.cn; He Meilan; Wang Hui; Qiao Bin; Chen Ping; Gu Hua; Zhang Mengjie; He Shengxiang

    2007-01-05

    NK cells are key components of innate immune systems and their activities are regulated by cytokines and hormones. All-trans retinoic acid (ATRA), as a metabolite of vitamin A and an immunomodulatory hormone, plays an important role in regulating immune responses. In the present study, we investigated the effect of ATRA on human NK cell line NK92. We found that ATRA dose-dependently suppressed cytotoxic activities of NK92 cells without affecting their proliferation. To explore the mechanisms underlying the ATRA influence on NK92 cells, we examined the production of cytokines (TNF-{alpha}, IFN-{gamma}), gene expression of cytotoxic-associated molecules (perforin, granzyme B, nature killer receptors (NCRs), and NKG2D), and the activation of NF-{kappa}B pathways related with immune response. Our results demonstrated that ATRA suppressed NF-{kappa}B activity and prevented I{kappa}B{alpha} degradation in a dose-dependent way, inhibited IFN-{gamma} production and gene expression of granzyme B and NKp46. Our findings suggest that ATRA is a negative regulator of NK92 cell activation and may act as a potential regulator of anti-inflammatory functions in vivo.

  4. Intracrine prostaglandin E(2) signalling regulates hypoxia-inducible factor-1α expression through retinoic acid receptor-β.

    PubMed

    Fernández-Martínez, Ana B; Jiménez, María I Arenas; Manzano, Victoria Moreno; Lucio-Cazaña, Francisco J

    2012-12-01

    We have previously found in human renal proximal tubular HK-2 cells that hypoxia- and all-trans retinoic acid-induced hypoxia-inducible factor-1α up-regulation is accompanied by retinoic acid receptor-β up-regulation. Here we first investigated whether hypoxia-inducible factor-1α expression is dependent on retinoic acid receptor-β and our results confirmed it since (i) hypoxia-inducible factor-1α-inducing agents hypoxia, hypoxia-mimetic agent desferrioxamine, all-trans retinoic acid and interleukin-1β increased retinoic acid receptor-β expression, (ii) hypoxia-inducible factor-1α up-regulation was prevented by retinoic acid receptor-β antagonist LE-135 or siRNA retinoic acid receptor-β and (iii) there was direct binding of retinoic acid receptor-β to the retinoic acid response element in hypoxia-inducible factor-1α promoter upon treatment with all-trans retinoic acid and 16,16-dimethyl-prostaglandin E(2). Since intracellular prostaglandin E(2) mediates hypoxia-inducible factor-1α up-regulation in normoxia in HK-2 cells, we next investigated and confirmed, its role in the up-regulation of retinoic acid receptor-β in normoxia by hypoxia-inducible factor-1α-inducing agents all-trans retinoic acid, interleukin-1β and 16,16-dimethyl-prostaglandin E(2) by inhibiting cyclooxygenases, prostaglandin influx transporter or EP receptors. Interestingly, the hypoxia-induced increase in retinoic acid receptor-β expression and accumulation of hypoxia-inducible factor-1α was also blocked by the inhibitors tested. This is the first time, to our knowledge, that retinoic acid receptor-β signalling is involved in the control of the expression of transcription factor hypoxia-inducible factor-1α in both normoxia and hypoxia and that retinoic acid receptor-β expression is found to be strictly regulated by intracellular prostaglandin E(2). Given the relevance of hypoxia-inducible factor-1α in the kidney in terms of tumorigenesis, progressive renal failure, production

  5. Loss of Nuclear Receptor SHP Impairs but Does Not Eliminate Negative Feedback Regulation of Bile Acid Synthesis

    PubMed Central

    Kerr, Thomas A.; Saeki, Shigeru; Schneider, Manfred; Schaefer, Karen; Berdy, Sara; Redder, Thadd; Shan, Bei; Russell, David W.; Schwarz, Margrit

    2014-01-01

    Summary The in vivo role of the nuclear receptor SHP in feedback regulation of bile acid synthesis was examined. Loss of SHP in mice caused abnormal accumulation and increased synthesis of bile acids due to derepression of rate-limiting CYP7A1 and CYP8B1 hydroxylase enzymes in the biosynthetic pathway. Dietary bile acids induced liver damage and restored feedback regulation. A synthetic agonist of the nuclear receptor FXR was not hepatotoxic and had no regulatory effects. Reduction of the bile acid pool with cholestyramine enhanced CYP7A1 and CYP8B1 expression. We conclude that input from three negative regulatory pathways controls bile acid synthesis. One is mediated by SHP, and two are SHP independent and invoked by liver damage and changes in bile acid pool size. PMID:12062084

  6. Teaching the Role of Secretin in the Regulation of Gastric Acid Secretion Using a Classic Paper by Johnson and Grossman

    ERIC Educational Resources Information Center

    Walton, Kristen L. W.

    2009-01-01

    The regulation of gastric acid secretion has been the subject of investigation for over a century. Inhibition of gastrin-induced acid secretion by the intestine-derived hormone secretin provides a classic physiological example of negative feedback in the gastrointestinal tract. A classic paper by Leonard R. Johnson and Morton I. Grossman clearly…

  7. Regulation of hepatic branched-chain alpha-keto acid dehydrogenase complex in rats fed a high-fat diet

    USDA-ARS?s Scientific Manuscript database

    Objective: Branched-chain alpha-keto acid dehydrogenase complex (BCKDC) regulates branched-chain amino acid (BCAA) metabolism at the level of branched chain alpha-ketoacid (BCKA) catabolism. It has been demonstrated that the activity of hepatic BCKDC is markedly decreased in type 2 diabetic animal...

  8. Teaching the Role of Secretin in the Regulation of Gastric Acid Secretion Using a Classic Paper by Johnson and Grossman

    ERIC Educational Resources Information Center

    Walton, Kristen L. W.

    2009-01-01

    The regulation of gastric acid secretion has been the subject of investigation for over a century. Inhibition of gastrin-induced acid secretion by the intestine-derived hormone secretin provides a classic physiological example of negative feedback in the gastrointestinal tract. A classic paper by Leonard R. Johnson and Morton I. Grossman clearly…

  9. Expression and regulation of retinoic acid receptors in human breast cancer cells.

    PubMed

    Roman, S D; Clarke, C L; Hall, R E; Alexander, I E; Sutherland, R L

    1992-04-15

    Retinoic acid is known to inhibit mammary carcinogenesis in rodents and to inhibit proliferation and steroid hormone receptor gene expression in human breast cancer cells. Since these effects are likely to be mediated by nuclear retinoic acid receptors (RARs) the present study was initiated to determine the expression and regulation of RARs in human breast cancer cell lines. Differential cellular gene expression of the RARs was determined by Northern blot analysis of total RNA prepared from 5 ER+ and 6 ER- cell lines. RAR alpha was detected as mRNA species of 2.7 and 3.4 kilobases in all cell lines and the level of gene expression was greater in ER+ cell lines (P less than 0.001). RAR beta mRNA (3.7 kilobases) was detected in seven of the eleven lines tested and was expressed most commonly in ER- cell lines. RAR gamma mRNA was expressed in all cell lines as a transcript of 3.4 kilobases at levels that were similar in both ER+ and ER- cell lines. Retinoic acid failed to regulate the expression of the RAR alpha and RAR gamma genes. The effect of steroid hormones on RAR alpha and RAR gamma mRNA levels was also examined. In four PR+ cell lines (T-47D, BT 474, MCF-7M, and MDA-MB-361), progestins markedly decreased RAR alpha mRNA levels. The progestin effect on RAR alpha levels in T-47D cells was detectable at concentrations of 0.05 nM and was maximal at 1 nM 16 alpha-ethyl-21-hydroxy-19-nor-4-pregnene-3,20-dione ORG 2058, whereas dihydrotestosterone and dexamethasone were without effect. RAR alpha and RAR gamma mRNA levels were rapidly decreased by progestin, and the effect was maximal 3-6 h after ORG 2058 treatment. However, the mRNA loss was transient, and recovery of RAR alpha and RAR gamma mRNA levels was noted 12-24 h after retinoic acid treatment. Although RAR gamma mRNA returned to control levels by 24 h, the decrease in RAR alpha mRNA was maintained at around 50% control until at least 48 h. In summary, RAR alpha and RAR gamma were expressed in all human breast

  10. Coordinated Regulation of Species-Specific Hydroxycinnamic Acid Degradation and Siderophore Biosynthesis Pathways in Agrobacterium fabrum

    PubMed Central

    Baude, Jessica; Vial, Ludovic; Villard, Camille; Campillo, Tony; Lavire, Céline; Nesme, Xavier

    2016-01-01

    ABSTRACT The rhizosphere-inhabiting species Agrobacterium fabrum (genomospecies G8 of the Agrobacterium tumefaciens species complex) is known to degrade hydroxycinnamic acids (HCAs), especially ferulic acid and p-coumaric acid, via the novel A. fabrum HCA degradation pathway. Gene expression profiles of A. fabrum strain C58 were investigated in the presence of HCAs, using a C58 whole-genome oligoarray. Both ferulic acid and p-coumaric acid caused variations in the expression of more than 10% of the C58 genes. Genes of the A. fabrum HCA degradation pathway, together with the genes involved in iron acquisition, were among the most highly induced in the presence of HCAs. Two operons coding for the biosynthesis of a particular siderophore, as well as genes of the A. fabrum HCA degradation pathway, have been described as being specific to the species. We demonstrate here their coordinated expression, emphasizing the interdependence between the iron concentration in the growth medium and the rate at which ferulic acid is degraded by cells. The coordinated expression of these functions may be advantageous in HCA-rich but iron-starved environments in which microorganisms have to compete for both iron and carbon sources, such as in plant roots. The present results confirm that there is cooperation between the A. fabrum-specific genes, defining a particular ecological niche. IMPORTANCE We previously identified seven genomic regions in Agrobacterium fabrum that were specifically present in all of the members of this species only. Here we demonstrated that two of these regions, encoding the hydroxycinnamic acid degradation pathway and the iron acquisition pathway, were regulated in a coordinated manner. The coexpression of these functions may be advantageous in hydroxycinnamic acid-rich but iron-starved environments in which microorganisms have to compete for both iron and carbon sources, such as in plant roots. These data support the view that bacterial genomic species

  11. γ-Polyglutamic acid/chitosan nanoparticles for the plant growth regulator gibberellic acid: Characterization and evaluation of biological activity.

    PubMed

    Pereira, A E S; Sandoval-Herrera, I E; Zavala-Betancourt, S A; Oliveira, H C; Ledezma-Pérez, A S; Romero, J; Fraceto, L F

    2017-02-10

    The growth regulator gibberellic acid (GA3) has several uses in the field, improving germination, plant development, productivity, and the quality of food. This work describes the development of a nanocarrier system for GA3, based on the poly(γ-glutamic acid) (γ-PGA) and chitosan (CS) polymers, Nanoparticles without GA3 (nano-γPGA/CS-GA3) showed colloidal characteristics, with an average size of 117±9nm, PDI of 0.43±0.07, and zeta potential of -29±0.5mV. The encapsulated nanoparticles (nano-γPGA/CS-GA3) presented an average size of 134±9nm, PDI of 0.35±0.05, zeta potential of 27.9±0.5mV, and 61% encapsulation. The images of nanoparticles observed by Transmission and scanning electron microscopy (TEM and SEM) showed a spherical shape of the nanoparticles. The system showed sustained release, with 58% release after 48h. Evaluation of thermal properties using DSC and TGA analyses indicated that there was an interaction between the CS and γ-PGA polymers. In tests using Phaseolus vulgaris seeds, nano-γPGA/CS-GA3 showed high biological activity, enhancing the rate of germination in the first day (50-70%) when compared with free GA3 (10-16%). Encapsulated GA3 was also more efficient than the free hormone in the increase of leaf area and the induction of root development (including the formation of lateral roots). These effects were not observed when seeds were treated with nano-γPGA/CS without GA3. The results demonstrated the considerable potential of nano-γPGA/CS-GA3 for use in agriculture. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Branched Fatty Acid Esters of Hydroxy Fatty Acids (FAHFAs) Protect against Colitis by Regulating Gut Innate and Adaptive Immune Responses.

    PubMed

    Lee, Jennifer; Moraes-Vieira, Pedro M; Castoldi, Angela; Aryal, Pratik; Yee, Eric U; Vickers, Christopher; Parnas, Oren; Donaldson, Cynthia J; Saghatelian, Alan; Kahn, Barbara B

    2016-10-14

    We recently discovered a structurally novel class of endogenous lipids, branched palmitic acid esters of hydroxy stearic acids (PAHSAs), with beneficial metabolic and anti-inflammatory effects. We tested whether PAHSAs protect against colitis, which is a chronic inflammatory disease driven predominantly by defects in the innate mucosal barrier and adaptive immune system. There is an unmet clinical need for safe and well tolerated oral therapeutics with direct anti-inflammatory effects. Wild-type mice were pretreated orally with vehicle or 5-PAHSA (10 mg/kg) and 9-PAHSA (5 mg/kg) once daily for 3 days, followed by 10 days of either 0% or 2% dextran sulfate sodium water with continued vehicle or PAHSA treatment. The colon was collected for histopathology, gene expression, and flow cytometry. Intestinal crypt fractions were prepared for ex vivo bactericidal assays. Bone marrow-derived dendritic cells pretreated with vehicle or PAHSA and splenic CD4(+) T cells from syngeneic mice were co-cultured to assess antigen presentation and T cell activation in response to LPS. PAHSA treatment prevented weight loss, improved colitis scores (stool consistency, hematochezia, and mouse appearance), and augmented intestinal crypt Paneth cell bactericidal potency via a mechanism that may involve GPR120. In vitro, PAHSAs attenuated dendritic cell activation and subsequent T cell proliferation and Th1 polarization. The anti-inflammatory effects of PAHSAs in vivo resulted in reduced colonic T cell activation and pro-inflammatory cytokine and chemokine expression. These anti-inflammatory effects appear to be partially GPR120-dependent. We conclude that PAHSA treatment regulates innate and adaptive immune responses to prevent mucosal damage and protect against colitis. Thus, PAHSAs may be a novel treatment for colitis and related inflammation-driven diseases. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Up-regulation of the expression of the gene for liver fatty acid-binding protein by long-chain fatty acids.

    PubMed Central

    Meunier-Durmort, C; Poirier, H; Niot, I; Forest, C; Besnard, P

    1996-01-01

    The role of fatty acids in the expression of the gene for liver fatty acid-binding protein (L-FABP) was investigated in the well-differentiated FAO rat hepatoma cell line. Cells were maintained in serum-free medium containing 40 microM BSA/320 microM oleate. Western blot analysis showed that oleate triggered an approx. 4-fold increase in the cytosolic L-FABP level in 16 h. Oleate specifically stimulated L-FABP mRNA in time-dependent and dose-dependent manners with a maximum 7-fold increase at 16 h in FAO cells. Preincubation of FAO cells with cycloheximide prevented the oleate-mediated induction of L-FABP mRNA, showing that protein synthesis was required for the action of fatty acids. Run-on transcription assays demonstrated that the control of L-FABP gene expression by oleate was, at least in part, transcriptional. Palmitic acid, oleic acid, linoleic acid, linolenic acid and arachidonic acid were similarly potent whereas octanoic acid was inefficient. This regulation was also found in normal hepatocytes. Therefore long-chain fatty acids are strong inducers of L-FABP gene expression. FAO cells constitute a useful tool for studying the underlying mechanism of fatty acid action. PMID:8912685

  14. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation.

    PubMed

    Sharma, Naveen; Okere, Isidore C; Brunengraber, Daniel Z; McElfresh, Tracy A; King, Kristen L; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Stanley, William C

    2005-01-15

    A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with (14)C-glucose and (3)H-oleate. Compared with control, the high workload groups had a similar increase in myocardial oxygen consumption ( and cardiac power. Dob increased PDH activity and glucose oxidation above control, but did not reduce the [NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH] ratios, and there were no differences between the Dob and Dob + Glu groups. An additional group was treated with Dob + Glu and oxfenicine (Oxf) to inhibit fatty acid oxidation: this increased [CoA-SH] and glucose oxidation compared with Dob; however, there was no further activation of PDH or decrease in the [NADH]/[NAD(+)] ratio. Content of the 4-carbon CAC intermediates succinate, fumarate and malate increased 3-fold with Dob, but there was no change in citrate content, and the Dob + Glu and Dob + Glu + Oxf groups were not different from Dob. In conclusion, compared with normal conditions, at high myocardial energy expenditure (1) the increase in flux through PDH is regulated by activation of the enzyme complex and continues to be partially controlled through inhibition by fatty acid oxidation, and (2) there is expansion of the CAC pool size at the level of 4-carbon intermediates that is largely independent of myocardial fatty acid oxidation.

  15. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation

    PubMed Central

    Sharma, Naveen; Okere, Isidore C; Brunengraber, Daniel Z; McElfresh, Tracy A; King, Kristen L; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Stanley, William C

    2005-01-01

    A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD+] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with 14C-glucose and 3H-