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Sample records for anion transporting polypeptide

  1. Organic anion transporting polypeptide 1B transporters modulate hydroxyurea pharmacokinetics

    Science.gov (United States)

    Lancaster, Cynthia S.; Finkelstein, David; Ware, Russell E.; Sparreboom, Alex

    2013-01-01

    Hydroxyurea is currently the only FDA-approved drug that ameliorates the pathophysiology of sickle cell anemia. Unfortunately, substantial interpatient variability in the pharmacokinetics (PK) of hydroxyurea may result in variation of the drug's efficacy. However, little is known about mechanisms that modulate hydroxyurea PK. Recent in vitro studies identifying hydroxyurea as a substrate for organic anion transporting polypeptide (OATP1B) transporters prompted the current investigation assessing the role of OATP1B transporters in modulating hydroxyurea PK. Using wild-type and Oatp1b knockout (Oatp1b−/−) mice, hydroxyurea PK was analyzed in vivo by measuring [14C]hydroxyurea distribution in plasma, kidney, liver, urine, or the exhaled 14CO2 metabolite. Plasma levels were significantly reduced by 20% in Oatp1b−/− mice compared with wild-type (area under the curve of 38.64 or 48.45 μg·h−1·ml−1, respectively) after oral administration, whereas no difference was observed between groups following intravenous administration. Accumulation in the kidney was significantly decreased by twofold in Oatp1b−/− mice (356.9 vs. 748.1 pmol/g), which correlated with a significant decrease in urinary excretion. Hydroxyurea accumulation in the liver was also decreased (136.6 vs. 107.3 pmol/g in wild-type or Oatp1b−/− mice, respectively) correlating with a decrease in exhaled 14CO2. These findings illustrate that deficiency of Oatp1b transporters alters the absorption, distribution, and elimination of hydroxyurea thus providing the first in vivo evidence that cell membrane transporters may play a significant role in modulating hydroxyurea PK. Future studies to investigate other transporters and their role in hydroxyurea disposition are warranted for understanding the sources of variation in hydroxyurea's PK. PMID:23986199

  2. Polyspecific organic anion transporting polypeptides mediate hepatic uptake of amphipathic type II organic cations

    NARCIS (Netherlands)

    van Montfoort, J.E; Hagenbuch, B; Fattinger, K.E; Muller, M; Groothuis, Geny; Meijer, D.K F; Meier, P.J

    1999-01-01

    Hepatic uptake of albumin-bound amphipathic organic cations has been suggested to be mediated by multispecific bile salt and organic anion transport systems. Therefore, we investigated whether the recently cloned rat organic anion transporting polypeptides 1 and 2 as well as the human organic anion

  3. Organic anion transporter 3- and organic anion transporting polypeptides 1B1- and 1B3-mediated transport of catalposide

    Directory of Open Access Journals (Sweden)

    Jeong HU

    2015-01-01

    Full Text Available Hyeon-Uk Jeong,1 Mihwa Kwon,2 Yongnam Lee,3 Ji Seok Yoo,3 Dae Hee Shin,3 Im-Sook Song,2 Hye Suk Lee1 1College of Pharmacy, The Catholic University of Korea, Bucheon 420-743, Korea; 2College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Korea; 3Central R&D Institute, Yungjin Pharm Co., Ltd., Suwon 443-270, Korea Abstract: We investigated the in vitro transport characteristics of catalposide in HEK293 cells overexpressing organic anion transporter 1 (OAT1, OAT3, organic anion transporting polypeptide 1B1 (OATP1B1, OATP1B3, organic cation transporter 1 (OCT1, OCT2, P-glycoprotein (P-gp, and breast cancer resistance protein (BCRP. The transport mechanism of catalposide was investigated in HEK293 and LLC-PK1 cells overexpressing the relevant transporters. The uptake of catalposide was 319-, 13.6-, and 9.3-fold greater in HEK293 cells overexpressing OAT3, OATP1B1, and OATP1B3 transporters, respectively, than in HEK293 control cells. The increased uptake of catalposide via the OAT3, OATP1B1, and OATP1B3 transporters was decreased to basal levels in the presence of representative inhibitors such as probenecid, furosemide, and cimetidine (for OAT3 and cyclosporin A, gemfibrozil, and rifampin (for OATP1B1 and OATP1B3. The concentration-dependent OAT3-mediated uptake of catalposide revealed the following kinetic parameters: Michaelis constant (Km =41.5 µM, maximum uptake rate (Vmax =46.2 pmol/minute, and intrinsic clearance (CLint =1.11 µL/minute. OATP1B1- and OATP1B3-mediated catalposide uptake also showed concentration dependency, with low CLint values of 0.035 and 0.034 µL/minute, respectively. However, the OCT1, OCT2, OAT1, P-gp, and BCRP transporters were apparently not involved in the uptake of catalposide into cells. In addition, catalposide inhibited the transport activities of OAT3, OATP1B1, and OATP1B3 with half-maximal inhibitory concentration values of 83, 200, and 235 µ

  4. Organic anion transporting polypeptide 2 transports valproic acid in rat brain microvascular endothelial cells.

    Science.gov (United States)

    Guo, Yi; Jiang, Li

    2016-07-01

    Abnormal drug transporter expression or function in the brain may lead to decreased concentrations of antiepileptic drugs (AEDs) in the central nervous system in patients with drug-resistant epilepsy. We previously showed the influx transporter organic anion transport polypeptide 2 (Oatp2) was expressed in rat brain microvascular endothelial cells (BMECs). Seizures decrease expression of Oatp2, but it remains unclear whether Oatp2 transports AEDs. In this study, we utilized rat BMECs as an in vitro model of the blood-brain barrier (BBB) to study Oatp2-mediated transport of valproic acid (VPA), the most common clinically used AEDs. In vivo injection of pregnenolone-16-carbonitrile was used to induce high expression of Oatp2 in isolated BMECs. Small interfering RNA treatment was used to silence Oatp2, and uptake of VPA was assessed. Increased expression of Oatp2 in BMECs increased the uptake of VPA, while inhibition of Oatp2 reduced VPA uptake. This study indicates Oatp2 transports VPA across the BBB, and suggests altered Oatp2 expression may contribute to resistance to VPA in patients with drug-resistant epilepsy.

  5. Uptake of perfluorooctanoic acid by Caco-2 cells: Involvement of organic anion transporting polypeptides.

    Science.gov (United States)

    Kimura, Osamu; Fujii, Yukiko; Haraguchi, Koichi; Kato, Yoshihisa; Ohta, Chiho; Koga, Nobuyuki; Endo, Tetsuya

    2017-08-05

    The mechanism underlying the intestinal absorption of perfluorooctanoic acid (PFOA) was investigated using Caco-2 cells. The uptake of PFOA from the apical membrane of Caco-2 cells was fast, and pH, temperature, and concentration dependent, but Na + independent. Coincubation with sulfobromophthalein (BSP), glibenclamide, estron-3-sulfate, cyclosporine A or rifamycin SV, which are typical substrates or inhibitors of organic anion transporting polypeptides (OATPs), significantly decreased the uptake of PFOA. However, coincubation with probenecid or p-aminohippuric acid, typical substrates of organic anion transporters, did not decrease the uptake of PFOA. Furthermore, coincubation with l-lactic acid or benzoic acid, substrates of monocarboxylic acid transporters, did not decrease PFOA uptake. The relationship between the initial uptake of PFOA and its concentration was saturable, suggesting the involvement of a carrier-mediated process. The calculated K m and uptake clearance (V max /K m ) values for PFOA were 8.3μM and 55.0μL/mg protein/min, respectively. This clearance value was about 3-fold greater than that of the non-saturable uptake clearance (K d : 18.1μL/mg protein/min). Lineweaver-Burk plots revealed that BSP competitively inhibits the uptake of PFOA, with a K i value of 23.1μM. These results suggest that the uptake of PFOA from the apical membranes of Caco-2 cells could be, at least in part, mediated by OATPs along with BSP. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Genetics or environment in drug transport: the case of organic anion transporting polypeptides and adverse drug reactions.

    Science.gov (United States)

    Clarke, John D; Cherrington, Nathan J

    2012-03-01

    Organic anion transporting polypeptide (OATP) uptake transporters are important for the disposition of many drugs and perturbed OATP activity can contribute to adverse drug reactions (ADRs). It is well documented that both genetic and environmental factors can alter OATP expression and activity. Genetic factors include single nucleotide polymorphisms (SNPs) that change OATP activity and epigenetic regulation that modify OATP expression levels. SNPs in OATPs contribute to ADRs. Environmental factors include the pharmacological context of drug-drug interactions and the physiological context of liver diseases. Liver diseases such as non-alcoholic fatty liver disease, cholestasis and hepatocellular carcinoma change the expression of multiple OATP isoforms. The role of liver diseases in the occurrence of ADRs is unknown. This article covers the roles OATPs play in ADRs when considered in the context of genetic or environmental factors. The reader will gain a greater appreciation for the current evidence regarding the salience and importance of each factor in OATP-mediated ADRs. A SNP in a single OATP transporter can cause changes in drug pharmacokinetics and contribute to ADRs but, because of overlap in substrate specificities, there is potential for compensatory transport by other OATP isoforms. By contrast, the expression of multiple OATP isoforms is decreased in liver diseases, reducing compensatory transport and thereby increasing the probability of ADRs. To date, most research has focused on the genetic factors in OATP-mediated ADRs while the impact of environmental factors has largely been ignored.

  7. Interactions between crude drug extracts used in Japanese traditional Kampo medicines and organic anion-transporting polypeptide 2B1.

    Science.gov (United States)

    Iijima, Rie; Watanabe, Tomoki; Ishiuchi, Kan'ichiro; Matsumoto, Takashi; Watanabe, Junko; Makino, Toshiaki

    2018-03-25

    The use of herbal medicines has become popular worldwide, and the information on drug interactions between herbal medicines and chemical drugs is needed. We screened the inhibitory effects of crude drugs used in Kampo medicines used in Japan on organic anion-transporting polypeptide (OATP) 2B1 to predict potential interactions between Kampo medicines and chemical drugs used together. We chose 98 kinds of crude drugs frequently used as ingredients of Kampo formulations in Japan and prepared their boiling water extracts. We then screened their inhibitory effects on OATP2B1 by measuring the uptake of estrone 3-sulphate (E3S) by HEK293 cells stably expressing OATP2B1. At the concentration of 100µg/ml, the extracts prepared from 12 kinds of crude drugs, Scuteralliae Radix, Arecae Semen, Aurantii Fructus Immaturus, Perillae Herba, Panacis Japonici Rhizoma, Moutan Cortex, Polygalae Radix, Rhei Rhizoma, Cannabis Fructus, Chrysanthemi Flos, Eriobotryae Folium, and Querci Cortex, suppressed the function of OATP2B1 by less than 20%. The extract of bofutsushosan, a representative Kampo formulation, inhibited OATP2B1 function with sufficient levels to suppress absorption of OATP2B1 substrates in clinics. We further evaluated the inhibitory effects of several ingredients containing Rhei Rhizoma, Perillae Herba, and Moutan Cortex on OATP2B1. Because of crude drugs used in Kampo medicines might suppress absorption of OATP2B1 substrates, these results may contribute to the safe and effective use of Kampo medicine in clinics. A list of abbreviations: EC, (-)-epicatechin; ECG, epicatechin gallate; EGC, epigallocatechin; EGCG, Epigallocatechin gallate; FBS, fetal bovine serum; grapefruit juice; HEK293, Human embryonic kidney; IC 50, The half inhibitory concentration; OATP, organic anion-transporting polypeptide; β-PGG, penta-O-galloyl-β-D-glucose; t.i.d, 3 times a day. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Epigenetic regulation of organic anion transporting polypeptide 1B3 in cancer cell lines.

    Science.gov (United States)

    Imai, Satoki; Kikuchi, Ryota; Tsuruya, Yuri; Naoi, Sotaro; Nishida, Sho; Kusuhara, Hiroyuki; Sugiyama, Yuichi

    2013-11-01

    The expression of a multispecific organic anion transporter, OATP1B3/SLCO1B3, is associated with clinical prognosis and survival of cancer cells. The aims of present study were to investigate the involvement of epigenetic regulation in mRNA expression of a cancer-type variant of OATP1B3 (Ct-OATP1B3) in cancer cell lines. The membrane localization and transport functions of Ct-OATP1B3 were investigated in HEK293 cells transiently expressing Ct-OATP1B3. DNA methylation profiles around the transcriptional start site of Ct-OATP1B3 in cancer cell lines were determined. The effects of a DNA methyltransferase inhibitor and siRNA knockdown of methyl-DNA binding proteins (MBDs) on the expression of Ct-OATP1B3 mRNA were investigated. 5'-RACE identified the TSS of Ct-OATP1B3 in PK-8 cells. Ct-OATP1B3 was localized on the plasma membrane, and showed the transport activities of E217βG, fluvastatin, rifampicin, and Gd-EOB-DTPA. The CpG dinucleotides were hypomethylated in Ct-OATP1B3-positive cell lines (DLD-1, TFK-1, PK-8, and PK-45P) but were hypermethylated in Ct-OATP1B3-negative cell lines (HepG2 and Caco-2). Treatment with a DNA methyltransferase inhibitor and siRNA knockdown of MBD2 significantly increased the expression of Ct-OATP1B3 mRNA in HepG2 and Caco-2. Ct-OATP1B3 is capable of transporting its substrates into cancer cells. Its mRNA expression is regulated by DNA methylation-dependent gene silencing involving MBD2.

  9. DNA methylation profiles of organic anion transporting polypeptide 1B3 in cancer cell lines.

    Science.gov (United States)

    Ichihara, Sayaka; Kikuchi, Ryota; Kusuhara, Hiroyuki; Imai, Satoki; Maeda, Kazuya; Sugiyama, Yuichi

    2010-03-01

    Multispecific organic anion transporter, OATP1B3/SLCO1B3, is expressed in several cancer cell lines as well as tumor tissues, and its expression sensitizes the cells to some anti-cancer agents. The present study was aimed to characterize the DNA methylation profiles around the transcriptional start site (TSS) of OATP1B3 and correlate them with the mRNA expression in cancer and immortalized cell lines. The mRNA expression and DNA methylation profiles of OATP1B3 were determined by RT-PCR and bisulfite sequencing, respectively. The expression of OATP1B3 mRNA was detected in DLD-1, TFK-1, PK-8, and PK-45P cells, but below the limit of detection in HepG2, Caco-2, and HEK293 cells. Bisulfite sequencing demonstrated that CpG dinucleotides around the TSS are differentially methylated among cell lines and partly associated with the mRNA expression profile of OATP1B3. Furthermore, treatment with 5-aza-2'-deoxycytidine, an inhibitor of DNA methyltransferase, significantly increased the mRNA expression of OATP1B3 in HepG2 and Caco-2 cells by 18- and 14-fold, respectively, but not in DLD-1 and TFK-1 cells. DNA methylation-dependent gene silencing is at least partly involved in the regulation of OATP1B3 expression in cancer/immortalized cell lines.

  10. The role of organic anion transporting polypeptides in drug absorption, distribution, excretion and drug-drug interactions.

    Science.gov (United States)

    Kovacsics, Daniella; Patik, Izabel; Özvegy-Laczka, Csilla

    2017-04-01

    The in vivo fate and effectiveness of a drug depends highly on its absorption, distribution, metabolism, excretion and toxicity (ADME-Tox). Organic anion transporting polypeptides (OATPs) are membrane proteins involved in the cellular uptake of various organic compounds, including clinically used drugs. Since OATPs are significant players in drug absorption and distribution, modulation of OATP function via pharmacotherapy with OATP substrates/inhibitors, or modulation of their expression, affects drug pharmacokinetics. Given their cancer-specific expression, OATPs may also be considered anticancer drug targets. Areas covered: We describe the human OATP family, discussing clinically relevant consequences of altered OATP function. We offer a critical analysis of published data on the role of OATPs in ADME and in drug-drug interactions, especially focusing on OATP1A2, 1B1, 1B3 and 2B1. Expert opinion: Four members of the OATP family, 1A2, 1B1, 1B3 and 2B1, have been characterized in detail. As biochemical and pharmacological knowledge on the other OATPs is lacking, it seems timely to direct research efforts towards developing the experimental framework needed to investigate the transport mechanism and substrate specificity of the poorly described OATPs. In addition, elucidating the role of OATPs in tumor development and therapy response are critical avenues for further research.

  11. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, Marta; Zaja, Roko [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia); Fent, Karl [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology (ETH Zürich), Department of Environmental System Sciences, Institute of Biogeochemistry and Pollution Dynamics, CH-8092 Zürich (Switzerland); Smital, Tvrtko, E-mail: smital@irb.hr [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia)

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  12. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    International Nuclear Information System (INIS)

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2014-01-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  13. Age- and sex-related differences of organic anion-transporting polypeptide gene expression in livers of rats

    International Nuclear Information System (INIS)

    Hou, Wei-Yu; Xu, Shang-Fu; Zhu, Qiong-Ni; Lu, Yuan-Fu; Cheng, Xing-Guo; Liu, Jie

    2014-01-01

    Organic anion-transporting polypeptides (Oatps) play important roles in transporting endogenous substances and xenobiotics into the liver and are implicated in drug-drug interactions. Many factors could influence their expression and result in alterations in drug disposition, efficacy and toxicity. This study was aimed to examine the development-, aging-, and sex-dependent Oatps expression in livers of rats. The livers from SD rats during development (− 2, 1, 7, 14, 21, 28, 35, and 60 d) and aging (60, 180, 540 and/or 800 d) were collected and total RNAs were extracted, purified, and subjected to real-time PCR analysis. Total proteins were extracted for western-blot analysis. Results showed that Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 were all hardly detectable in fetal rat livers, low at birth, rapidly increased after weaning (21 d), and reached the peak at 60 d. The Oatps remained stable during the age between 60–180 d, and decreased at elderly (540 and/or 800 d). After birth, Oatp1a1, Oatp1a4, and Oatp1b2 were all highly expressed in liver, in contrast, Oatp1a5 expression was low. Oatp expressions are male-predominant in rat livers. In the livers of aged rats, the Oatp expression decreased and shared a consistent ontogeny pattern at the mRNA and protein level. In conclusion, this study showed that in rat liver, Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 gene expressions are influenced by age and gender, which could provide a basis of individual variation in drug transport, metabolism and toxicity in children, elderly and women. - Highlights: • Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 expression in livers of rats. • Ontogenic changes of Oatps at − 2, 1, 7, 14, 21, 28, 35, and 60 days. • Age-related changes of Oatps at 60, 180, 540, and 800 days. • Sex-difference of Oatps at the both mRNA and protein levels

  14. Age- and sex-related differences of organic anion-transporting polypeptide gene expression in livers of rats

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Wei-Yu; Xu, Shang-Fu; Zhu, Qiong-Ni; Lu, Yuan-Fu [Key Lab for Pharmacology of Ministry of Education, Zunyi Medical College, Zunyi 563003 (China); Cheng, Xing-Guo [Department of Pharmaceutical Sciences, St. John’s University, New York, NY 11439 (United States); Liu, Jie, E-mail: Jieliu@zmc.edu.cn [Key Lab for Pharmacology of Ministry of Education, Zunyi Medical College, Zunyi 563003 (China)

    2014-10-15

    Organic anion-transporting polypeptides (Oatps) play important roles in transporting endogenous substances and xenobiotics into the liver and are implicated in drug-drug interactions. Many factors could influence their expression and result in alterations in drug disposition, efficacy and toxicity. This study was aimed to examine the development-, aging-, and sex-dependent Oatps expression in livers of rats. The livers from SD rats during development (− 2, 1, 7, 14, 21, 28, 35, and 60 d) and aging (60, 180, 540 and/or 800 d) were collected and total RNAs were extracted, purified, and subjected to real-time PCR analysis. Total proteins were extracted for western-blot analysis. Results showed that Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 were all hardly detectable in fetal rat livers, low at birth, rapidly increased after weaning (21 d), and reached the peak at 60 d. The Oatps remained stable during the age between 60–180 d, and decreased at elderly (540 and/or 800 d). After birth, Oatp1a1, Oatp1a4, and Oatp1b2 were all highly expressed in liver, in contrast, Oatp1a5 expression was low. Oatp expressions are male-predominant in rat livers. In the livers of aged rats, the Oatp expression decreased and shared a consistent ontogeny pattern at the mRNA and protein level. In conclusion, this study showed that in rat liver, Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 gene expressions are influenced by age and gender, which could provide a basis of individual variation in drug transport, metabolism and toxicity in children, elderly and women. - Highlights: • Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 expression in livers of rats. • Ontogenic changes of Oatps at − 2, 1, 7, 14, 21, 28, 35, and 60 days. • Age-related changes of Oatps at 60, 180, 540, and 800 days. • Sex-difference of Oatps at the both mRNA and protein levels.

  15. Organic anion transporting polypeptide 2B1 and breast cancer resistance protein interact in the transepithelial transport of steroid sulfates in human placenta.

    Science.gov (United States)

    Grube, Markus; Reuther, Sebastian; Meyer Zu Schwabedissen, Henriette; Köck, Kathleen; Draber, Katrin; Ritter, Christoph A; Fusch, Christoph; Jedlitschky, Gabriele; Kroemer, Heyo K

    2007-01-01

    The human placenta has both protective and nurturing functions for the fetal organism. Uptake and elimination of xenobiotics and endogenous substances are facilitated by various transport proteins from the solute carrier (SLC) and ABC families, respectively. A functional interaction of uptake and elimination, which is a prerequisite for vectorial transport across cellular barriers, has not been described for placenta. In this study, we examined expression of organic anion transporter (OAT) 4 (SLC22A11), organic anion transporting polypeptide (OATP) 2B1 (SLCO2B1, OATP-B), and breast cancer resistance protein (BCRP) (ABCG2) in human placenta (n = 71) because all three proteins are involved in transmembranal transfer of estrone 3 sulfate (E3S; metabolic product) and dehydroepiandrosterone sulfate (DHEAS; precursor molecule). On the mRNA level, we found a significant correlation of OATP2B1 and BCRP (R(2) = 0.534; p 0.05). Localization studies confirmed basal expression of OATP2B1 and apical expression of BCRP. To study functional interactions between OATP2B1 and BCRP, we developed a Madin-Darby canine kidney cell model expressing both transport proteins simultaneously (OATP2B1 and BCRP in the basal and apical membrane, respectively). Using this cell model in a transwell system resulted in a significantly increased basal to apical transport of both E3S and DHEAS, when both transporters were expressed with no change of transfer in the apical to basal direction. Taken together, these data show the potential for a functional interaction of OATP2B1 and BCRP in transepithelial transport of steroid sulfates in human placenta.

  16. Involvement of organic anion transporting polypeptide 1a5 (Oatp1a5) in intestinal absorption of endothelin receptor antagonist in rats

    DEFF Research Database (Denmark)

    Tani, Takeshe; Gram, Luise Kvisgaard; Arakawa, Hiroshi

    2008-01-01

    PURPOSE: To assess the contribution of organic anion transporting polypeptide 1a5 (Oatp1a5/Oatp3) in the intestinal absorption of an orally active endothelin receptor antagonist, (+)-(5S,6R,7R)-2-butyl-7-[2-((2S)-2-carboxypropyl)-4-methoxyphenyl]-5-(3,4-methylene-dioxyphenyl)cyclopenteno[1,2-b...... and taurocholic acid. CONCLUSIONS: These results consistently suggested that Oatp1a5 is contributing to the intestinal absorption of compound-A at least in part, and the transporter-mediated absorption seems to be maximized at the acidic microenvironment of epithelial cells in the small intestine in rats....

  17. Influence of non-steroidal anti-inflammatory drugs on organic anion transporting polypeptide (OATP) 1B1- and OATP1B3-mediated drug transport.

    Science.gov (United States)

    Kindla, Juergen; Müller, Fabian; Mieth, Maren; Fromm, Martin F; König, Jörg

    2011-06-01

    The transporter-mediated uptake of drugs from blood into hepatocytes is a prerequisite for intrahepatic drug action or intracellular drug metabolism before excretion. Therefore, uptake transporters, e.g., members of the organic anion transporting polypeptide (OATP) family are important determinants of drug pharmacokinetics. Highly and almost exclusively expressed in hepatocytes are the OATP family members OATP1B1 (SLCO1B1) and OATP1B3 (SLCO1B3). Drug substrates of OATP1B1 and OATP1B3 include antibiotics and HMG-CoA reductase inhibitors (statins). It has been demonstrated that administration of two or more drugs that are substrates for these hepatic uptake transporters may lead to transporter-mediated drug-drug interactions, resulting in altered transport kinetics for drug substrates. In this study we investigated whether non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol interact with OATP1B1 and OATP1B3 using the standard substrate BSP and the drug substrate pravastatin. Using human embryonic kidney cells stably expressing OATP1B1 or OATP1B3, we demonstrated that bromosulfophthalein uptake was inhibited by diclofenac, ibuprofen. and lumiracoxib. Of interest, pravastatin uptake was stimulated by these NSAIDs, and for ibuprofen we determined activation constants (EC₅₀ values) of 64.0 and 93.1 μM for OATP1B1- and OATP1B3-mediated uptake, respectively. Furthermore, we investigated whether NSAIDs were also substrates for OATP1B1 and OATP1B3 and demonstrated that only diclofenac was significantly transported by OATP1B3, whereas all other NSAIDs investigated were not substrates for these uptake transporters. These results demonstrated that drugs may interact with transport proteins by allosteric mechanisms without being substrates and, therefore, not only uptake inhibition but also allosteric-induced modulation of transport function may be an important mechanism in transporter-mediated drug-drug interactions.

  18. Expression of organic anion transporting polypeptide 1c1 and monocarboxylate transporter 8 in the rat placental barrier and the compensatory response to thyroid dysfunction.

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    Yi-na Sun

    Full Text Available Thyroid hormones (THs must pass from mother to fetus for normal fetal development and require the expression of placental TH transporters. We investigate the compensatory effect of placental organic anion transporting polypeptide 1c1 (Oatp1c1 and monocarboxylate transporter 8 (Mct8 on maternal thyroid dysfunction. We describe the expressions of these two transporters in placental barriers and trophoblastic cell populations in euthyroidism and thyroid dysfunction resulting from differential iodine nutrition at gestation day (GD 16 and 20, that is, before and after the onset of fetal thyroid function. Immunohistochemistry revealed that in the blood-placenta barrier, these two TH transporters were strongly expressed in the villous interstitial substance and were weakly expressed in trophoblast cells. Levels of Oatp1c1 protein obviously increased in the placental fetal portion during maternal thyroid deficiency at GD16. Under maternal thyroid deficiency after the production of endogenous fetal TH, quantitative PCR analysis revealed down-regulation of Oatp1c1 occurred along with up-regulation of Mct8 in trophoblast cell populations isolated by laser capture microdissection (LCM; this was consistent with the protein levels in the fetal portion of the placenta. In addition, decreased D3 mRNA at GD16 and increased D2 mRNA on two gestational days were observed in trophoblast cells with thyroid dysfunction. However, levels of Oatp1c1 mRNA at GD16 and D3 mRNA at GD20 were too low to be detectable in trophoblast cells. In conclusion, placental Oatp1c1 plays an essential compensatory role when the transplacental passage of maternal THs is insufficient at the stage before the fetal TH production. In addition, the coordinated effects of Oatp1c1, Mct8, D2 and D3 in the placental barrier may regulate both transplacental TH passage and the development of trophoblast cells during thyroid dysfunction throughout the pregnancy.

  19. Novel insights into xenobiotic transport by organic anion transporting polypeptides (OATPs) and OATP-expression profiling in ovarian carcinoma and other solid tumors

    International Nuclear Information System (INIS)

    Svoboda, M.

    2010-01-01

    Eleven members of the organic anion transporting polypeptides (OATP) family have been identified in humans. They are responsible for the Na+ independent cellular uptake of a broad range of substances. The aim of this thesis was to investigate the possible role of OATPs present in various cancer entities including breast, bone, liver and ovary. In the first study, carrier-mediated uptake of paclitaxel was studied in X. laevis oocytes expressing all known human OATPs and in ovarian cancer cell lines. OATP1B1 could be identified as an uptake transporter for paclitaxel showing a Km value of 0.6 μM indicating high affinity to this taxane. Subsequently, the expression status of OATPs and several ABC transporters was assessed in malignant specimens from 191 ovarian cancer patients. OATP3A1 was significantly correlated with the FIGO stage of tumors. Moreover, OATP6A1, ABCB2 and ABCC3 were identified as highly significant predictor for the disease free survival of ovarian cancer patients. In additional studies we showed distinct OATP expression patterns in cancer tissues compared to normal tissue or benign tumors. In general, higher OATP levels were detected in normal tissues compared to malignant ones in breast cancer as well as bone cancer. In liver cancer, we observed upregulation of OATP2A1 and 5A1 in primary and secondary hepatic tumors but OATP4A1 was only upregulated in secondary hepatic tumors. The distinct expression pattern for individual OATPs in tumor cells suggest their specific functions which may involve transport of molecules important for cellular signaling as well as of drugs used in therapy. (author) [de

  20. Comparative pharmacophore modeling of organic anion transporting polypeptides: a meta-analysis of rat Oatp1a1 and human OATP1B1.

    Science.gov (United States)

    Chang, Cheng; Pang, K Sandy; Swaan, Peter W; Ekins, Sean

    2005-08-01

    The organic anion transporting polypeptides OATPs are key membrane transporters for which crystal structures are not currently available. They transport a diverse array of xenobiotics and are expressed at the interface of hepatocytes, renal tubular cells, enterocytes, and the choroid plexus. To aid the understanding of the key molecular features for substrate-transporter interactions, pharmacophore models were produced for the two OATPs that have been most extensively studied, namely rat Oatp1a1 and human OATP1B1. Literature data from Chinese hamster ovary, HeLa, human embryonic kidney 293 cells, and Xenopus laevis oocytes were used to construct pharmacophores for each individual transporter which were later merged to show similarities across cell lines for the same transporter. Additionally, meta-pharmacophores were generated from the combined datasets of each cell system used with the same transporter. The pharmacophores for each transporter consisted of hydrogen bond acceptor and hydrophobic features. There was good agreement between the merged and meta-pharmacophores containing two hydrogen bond acceptors and two or three hydrophobic features for Oatp1a1 and OATP1B1. External test sets were used to validate the individual pharmacophores. The meta-pharmacophores were also used to make predictions for molecules not included in the models and provided new molecular insight into the key features for these OATP transporters. This approach can be extended to other transporters for which limited data are available.

  1. Tryptophan Residue Located at the Middle of Putative Transmembrane Domain 11 Is Critical for the Function of Organic Anion Transporting Polypeptide 2B1.

    Science.gov (United States)

    Bian, Jialin; Jin, Meng; Yue, Mei; Wang, Meiyu; Zhang, Hongjian; Gui, Chunshan

    2016-10-03

    Organic anion transporting polypeptide 2B1 (OATP2B1), which is highly expressed in enterocytes and hepatocytes could be a key determinant for the intestinal absorption and hepatic uptake of its substrates, most of which are amphipathic organic anions. Tryptophan residues may possess a multitude of functions for a transport protein through aromatic interactions, such as maintaining the proper protein structure, guiding the depth of membrane insertion, or interacting directly with substrates. There are totally six tryptophan residues in OATP2B1. However, little is known about their role in the function and expression of OATP2B1. Our results show that, while W272, W276, and W277 located at the border of extracellular loop 3 and transmembrane domain 6 exhibit a moderate effect on the surface expression of OATP2B1, W611 located at the middle of transmembrane domain 11 plays a critical role in the function of OATP2B1. The tryptophan-to-alanine mutation of W611 changes the kinetic characteristics of OATP2B1-mediated estrone-3-sulfate (E3S) transport radically, from a monophasic saturation curve (with K m and V max values being of 7.1 ± 1.1 μM and 182 ± 7 pmol/normalized mg/min, respectively) to a linear curve. Replacing alanine with a phenylalanine will rescue most of OATP2B1's function, suggesting that the aromatic side chain of residue 611 is very important. However, hydrogen-bond forming and positively charged groups at this position are not favorable. The important role of W611 is not substrate-dependent. Molecular modeling indicates that the side chain of W611 faces toward the substrate translocation pathway and might interact with substrates directly. Taken together, our findings reveal that W611 is critical for the function of OATP2B1.

  2. Comparison of the Predictability of Human Hepatic Clearance for Organic Anion Transporting Polypeptide Substrate Drugs Between Different In Vitro-In Vivo Extrapolation Approaches.

    Science.gov (United States)

    Izumi, Saki; Nozaki, Yoshitane; Komori, Takafumi; Takenaka, Osamu; Maeda, Kazuya; Kusuhara, Hiroyuki; Sugiyama, Yuichi

    2017-09-01

    Prediction of human pharmacokinetic profiles of drug candidates is an essential step toward first-in-human studies. However, it remains difficult to quantitatively predict hepatic clearance, particularly when hepatic uptake is mediated by transporter(s). Using 15 organic anion transporting polypeptide (OATP) substrate drugs, we tested 3 in vitro-in vivo extrapolation (IVIVE) approaches to predict overall hepatic intrinsic clearance in vivo (CL int,all,vivo ). IVIVE approaches involved metabolic intrinsic clearance in human liver microsomes (CL int,met ) with or without hepatocyte-to-buffer maximum unbound concentration ratio (K p,uu,max ) correction and uptake intrinsic clearance at 37°C (PS inf,37°C ) in human hepatocyte suspensions. K p,uu,max and PS inf,37°C values were determined in 2 hepatocyte batches, and all tested compounds showed temperature-dependent uptake, consistent with the fact of transporter-mediated uptake. CL int,met substantially underestimated CL int,all,vivo . By multiplying CL int,met by K p,uu,max values, the prediction performance was much improved; however, in vitro-in vivo correlation was poor. Among the IVIVE approaches, PS inf,37°C showed the most robust correlation with CL int,all,vivo , and one of the hepatocyte batches could predict CL int,all,vivo with a minimal empirical scaling factor. These results suggested IVIVE with hepatic uptake clearance determined in hepatocyte suspensions as one of the most practical approaches for predicting CL int,all,vivo of OATP substrate drugs. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  3. Hepatic uptake of conjugated bile acids is mediated by both sodium taurocholate cotransporting polypeptide and organic anion transporting polypeptides and modulated by intestinal sensing of plasma bile acid levels in mice.

    Science.gov (United States)

    Slijepcevic, Davor; Roscam Abbing, Reinout L P; Katafuchi, Takeshi; Blank, Antje; Donkers, Joanne M; van Hoppe, Stéphanie; de Waart, Dirk R; Tolenaars, Dagmar; van der Meer, Jonathan H M; Wildenberg, Manon; Beuers, Ulrich; Oude Elferink, Ronald P J; Schinkel, Alfred H; van de Graaf, Stan F J

    2017-11-01

    The Na + -taurocholate cotransporting polypeptide (NTCP/SLC10A1) is believed to be pivotal for hepatic uptake of conjugated bile acids. However, plasma bile acid levels are normal in a subset of NTCP knockout mice and in mice treated with myrcludex B, a specific NTCP inhibitor. Here, we elucidated which transport proteins mediate the hepatic uptake of conjugated bile acids and demonstrated intestinal sensing of elevated bile acid levels in plasma in mice. Mice or healthy volunteers were treated with myrcludex B. Hepatic bile acid uptake kinetics were determined in wild-type (WT), organic anion transporting polypeptide (OATP) knockout mice (lacking Slco1a/1b isoforms), and human OATP1B1-transgenic mice. Effects of fibroblast growth factor 19 (FGF19) on hepatic transporter mRNA levels were assessed in rat hepatoma cells and in mice by peptide injection or adeno-associated virus-mediated overexpression. NTCP inhibition using myrcludex B had only moderate effects on bile acid kinetics in WT mice, but completely inhibited active transport of conjugated bile acid species in OATP knockout mice. Cholesterol 7α-hydroxylase Cyp7a1 expression was strongly down-regulated upon prolonged inhibition of hepatic uptake of conjugated bile acids. Fgf15 (mouse counterpart of FGF19) expression was induced in hypercholanemic OATP and NTCP knockout mice, as well as in myrcludex B-treated cholestatic mice, whereas plasma FGF19 was not induced in humans treated with myrcludex B. Fgf15/FGF19 expression was induced in polarized human enterocyte-models and mouse organoids by basolateral incubation with a high concentration (1 mM) of conjugated bile acids. NTCP and OATPs contribute to hepatic uptake of conjugated bile acids in mice, whereas the predominant uptake in humans is NTCP mediated. Enterocytes sense highly elevated levels of (conjugated) bile acids in the systemic circulation to induce FGF15/19, which modulates hepatic bile acid synthesis and uptake. (Hepatology 2017;66:1631-1643).

  4. Casein Kinase 2 Is a Novel Regulator of the Human Organic Anion Transporting Polypeptide 1A2 (OATP1A2) Trafficking.

    Science.gov (United States)

    Chan, Ting; Cheung, Florence Shin Gee; Zheng, Jian; Lu, Xiaoxi; Zhu, Ling; Grewal, Thomas; Murray, Michael; Zhou, Fanfan

    2016-01-04

    Human organic anion transporting polypeptides (OATPs) mediate the influx of many important drugs into cells. Casein kinase 2 (CK2) is a critical protein kinase that phosphorylates >300 protein substrates and is dysregulated in a number of disease states. Among the CK2 substrates are several transporters, although whether this includes human OATPs has not been evaluated. The current study was undertaken to evaluate the regulation of human OATP1A2 by CK2. HEK-239T cells in which OATP1A2 was overexpressed were treated with CK2 specific inhibitors or transfected with CK2 specific siRNA, and the activity, expression, and subcellular trafficking of OATP1A2 was evaluated. CK2 inhibition decreased the uptake of the prototypic OATP1A2 substrate estrone-3-sulfate (E3S). Kinetic studies revealed that this was due to a decrease in the maximum velocity (Vmax) of E3S uptake, while the Michaelis constant was unchanged. The cell surface expression, but not the total cellular expression of OATP1A2, was impaired by CK2 inhibition and knockdown of the catalytic α-subunits of CK2. CK2 inhibition decreased the internalization of OATP1A2 via a clathrin-dependent pathway, decreased OATP1A2 recycling, and likely impaired OATP1A2 targeting to the cell surface. Consistent with these findings, CK2 inhibition also disrupted the colocalization of OATP1A2 and Rab GTPase (Rab)4-, Rab8-, and Rab9-positive endosomal and secretory vesicles. Taken together, CK2 has emerged as a novel regulator of the subcellular trafficking and stability of OATP1A2. Because OATP1A2 transports many molecules of physiological and pharmacological importance, the present data may inform drug selection in patients with diseases in which CK2 and OATP1A2 are dysregulated.

  5. Characterization of simvastatin acid uptake by organic anion transporting polypeptide 3A1 (OATP3A1) and influence of drug-drug interaction.

    Science.gov (United States)

    Atilano-Roque, Amandla; Joy, Melanie S

    2017-12-01

    Human organic anion transporting polypeptide 3A1 (OATP3A1) is predominately expressed in the heart. The ability of OATP3A1 to transport statins into cardiomyocytes is unknown, although other OATPs are known to mediate the uptake of statin drugs in liver. The pleiotropic effects and uptake of simvastatin acid were analyzed in primary human cardiomyocytes and HEK293 cells transfected with the OATP3A1 gene. Treatment with simvastatin acid reduced indoxyl sulfate-mediated reactive oxygen species and modulated OATP3A1 expression in cardiomyocytes and HEK293 cells transfected with the OATP3A1 gene. We observed a pH-dependent effect on OATP3A1 uptake, with more efficient simvastatin acid uptake at pH5.5 in HEK293 cells transfected with the OATP3A1 gene. The Michaelis-Menten constant (K m ) for simvastatin acid uptake by OATP3A1 was 0.017±0.002μM and the V max was 0.995±0.027fmol/min/10 5 cells. Uptake of simvastatin acid was significantly increased by known (benzylpenicillin and estrone-3-sulfate) and potential (indoxyl sulfate and cyclosporine) substrates of OATP3A1. In conclusion, the presence of OATP3A1 in cardiomyocytes suggests that this transporter may modulate the exposure of cardiac tissue to simvastatin acid due to its enrichment in cardiomyocytes. Increases in uptake of simvastatin acid by OATP3A1 when combined with OATP substrates suggest the potential for drug-drug interactions that could influence clinical outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Thyroxine (T4 Transfer from Blood to Cerebrospinal Fluid in Sheep Isolated Perfused Choroid Plexus: Role of Multidrug Resistance-Associated Proteins and Organic Anion Transporting Polypeptides

    Directory of Open Access Journals (Sweden)

    Kazem Zibara

    2017-05-01

    Full Text Available Thyroxine (T4 enters the brain either directly across the blood–brain barrier (BBB or indirectly via the choroid plexus (CP, which forms the blood–cerebrospinal fluid barrier (B-CSF-B. In this study, using isolated perfused CP of the sheep by single-circulation paired tracer and steady-state techniques, T4 transport mechanisms from blood into lateral ventricle CP has been characterized as the first step in the transfer across the B-CSF-B. After removal of sheep brain, the CPs were perfused with 125I-T4 and 14C-mannitol. Unlabeled T4 was applied during single tracer technique to assess the mode of maximum uptake (Umax and the net uptake (Unet on the blood side of the CP. On the other hand, in order to characterize T4 protein transporters, steady-state extraction of 125I-T4 was measured in presence of different inhibitors such as probenecid, verapamil, BCH, or indomethacin. Increasing the concentration of unlabeled-T4 resulted in a significant reduction in Umax%, which was reflected by a complete inhibition of T4 uptake into CP. In fact, the obtained Unet% decreased as the concentration of unlabeled-T4 increased. The addition of probenecid caused a significant inhibition of T4 transport, in comparison to control, reflecting the presence of a carrier mediated process at the basolateral side of the CP and the involvement of multidrug resistance-associated proteins (MRPs: MRP1 and MRP4 and organic anion transporting polypeptides (Oatp1, Oatp2, and Oatp14. Moreover, verapamil, the P-glycoprotein (P-gp substrate, resulted in ~34% decrease in the net extraction of T4, indicating that MDR1 contributes to T4 entry into CSF. Finally, inhibition in the net extraction of T4 caused by BCH or indomethacin suggests, respectively, a role for amino acid “L” system and MRP1/Oatp1 in mediating T4 transfer. The presence of a carrier-mediated transport mechanism for cellular uptake on the basolateral membrane of the CP, mainly P-gp and Oatp2, would account

  7. Comparative effects of nodularin and microcystin-LR in zebrafish: 1. Uptake by organic anion transporting polypeptide Oatp1d1 (Slco1d1).

    Science.gov (United States)

    Faltermann, Susanne; Prétôt, René; Pernthaler, Jakob; Fent, Karl

    2016-02-01

    Microcystin-LR (MC-LR) and nodularin are hepatotoxins produced by several cyanobacterial species. Their toxicity is based on active cellular uptake and subsequent inhibition of protein phosphatases PP1/2A, leading to hyperphosphorylation and cell death. To date, uptake of MC-LR and nodularin in fish is poorly understood. Here, we investigated the role of the organic anion transporting polypeptide Oatp1d1 in zebrafish (drOatp1d1, Slco1d1) in cellular uptake in zebrafish. We stably transfected CHO and HEK293 cell lines expressing drOatp1d1. In both transfectants, uptake of MC-LR and nodularin was demonstrated by competitive inhibition of uptake with fluorescent substrate lucifer yellow. Direct uptake of MC-LR was demonstrated by immunostaining, and indirectly by the high cytotoxicity in stable transfectants. By means of a synthesized fluorescent labeled MC-LR derivative, direct uptake was further confirmed in HEK293 cells expressing drOatp1d1. Additionally, uptake and toxicity was investigated in the permanent zebrafish liver cell line ZFL. These cells had only a low relative abundance of drOatp1d1, drOatp2b1 and drOatp1f transcripts, which correlated with the lack of MC-LR induced cytotoxicity and transcriptional changes of genes indicative of endoplasmic reticulum stress, a known effect of this toxin. Our study demonstrates that drOatp1d1 functions as an uptake transporter for both MC-LR and nodularin in zebrafish. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Lack of Contribution of Multidrug Resistance-associated Protein and Organic Anion-transporting Polypeptide to Pharmacokinetics of Regorafenib, a Novel Multi-Kinase Inhibitor, in Rats.

    Science.gov (United States)

    Hotta, Kazuo; Ueyama, Jun; Tatsumi, Yasuaki; Tsukiyama, Ikuto; Sugiura, Yuka; Saito, Hiroko; Matsuura, Katsuhiko; Hasegawa, Takaaki

    2015-09-01

    We investigated whether hepatic multidrug resistance-associated protein 2 (ABCC2) is involved in the hepatobiliary excretion of regorafenib, a novel multi-kinase inhibitor, using Sprague-Dawley (SD) rats and Eisai hyperbilirubinemic rats (EHBR) lacking the efflux transporter ABCC2. The involvement of organic anion-transporting polypeptide 1 (OATP1; OATP in humans) and OATP2 in the hepatic uptake of regorafenib and their protein levels in the liver were also investigated in the two rat groups. When regorafenib (5 mg/kg) was administered intravenously, the plasma concentrations of regorafenib were higher in EHBR than those in SD rats. However, the slope of the plasma concentration-time curves was the same for the two groups. Although the apparent biliary clearance of regorafenib in EHBR was lower than that of SD rats, no significant difference in the biliary excretion rate was observed between them, suggesting that regorafenib is not a substrate for ABCC2 and is not excreted into bile by ABCC2. It was also found that the contribution of biliary excretion to the systemic elimination of regorafenib is small. The protein-binding profiles of regorafenib were found to be linear in both rat groups. The binding potency, which was very high in both rat groups (>99.5%), was significantly higher in EHBR than that in SD rats. No significant differences in the plasma concentrations of unbound regorafenib were observed between the two rat groups, suggesting that the differences observed in the pharmacokinetic behaviors of regorafenib between the two rat groups were due to differences in protein-binding. When the protein levels of hepatic OATP1 and OATP2 were measured by immunoblot analysis, the expression of both transporters in EHBR was less than 40% of that in SD rats. The present results suggest that regorafenib is not a substrate for OATP1 and OATP2. These findings suggest the possibility that ABCC2-mediated hepatobiliary excretion and OATP1/OATP2-mediated hepatic uptake do

  9. The eighth and ninth transmembrane domains in organic anion transporting polypeptide 1B1 affect the transport kinetics of estrone-3-sulfate and estradiol-17beta-D-glucuronide.

    Science.gov (United States)

    Miyagawa, Mayuko; Maeda, Kazuya; Aoyama, Akinori; Sugiyama, Yuichi

    2009-05-01

    Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 are responsible for the hepatic uptake of organic anions. They share similar sequences and structures with 12 putative transmembrane domains (TMs). Their substrate specificities are very broad and overlap each other, whereas each transporter specifically recognizes certain substrates. Because the homology of the amino acid sequence in the latter part of OATP1B1 and OATP1B3 is relatively low, to determine which TMs in the latter part of OATP1B1 are important for its substrate recognition, we constructed several cell lines expressing chimeric transporters in which some TMs of OATP1B1 were substituted with those of OATP1B3, and we investigated the transport kinetics of estrone-3-sulfate (E-sul; a substrate preferentially accepted by OATP1B1) and estradiol-17beta-D-glucuronide (EG; a substrate accepted by both transporters). As the number of substituted TMs at the N terminus with those of OATP1B3 increased, the K(m) value of E-sul greatly increased and its uptake clearance decreased. The substitution of TM7 or TM9 of OATP1B1 with that of OATP1B3 (named 1B1-TM7 or 1B1-TM9) did not change the transport kinetics of EG, whereas the K(m) value of E-sul in 1B1-TM9 increased 7.4-fold. Conversely, the substitution of TM8 resulted in an 18-fold increase in the K(m) value of E-sul and abolished the transporter-mediated uptake of EG. These results suggest that TM8 in OATP1B1 is critical for the substrate recognition of both E-sul and EG and that TM9 is important for the recognition of E-sul, whereas it is interchangeable with that of OATP1B3 for EG transport.

  10. Identification of amino acids essential for estrone-3-sulfate transport within transmembrane domain 2 of organic anion transporting polypeptide 1B1.

    Directory of Open Access Journals (Sweden)

    Nan Li

    Full Text Available As an important structure in membrane proteins, transmembrane domains have been found to be crucial for properly targeting the protein to cell membrane as well as carrying out transport functions in transporters. Computer analysis of OATP sequences revealed transmembrane domain 2 (TM2 is among those transmembrane domains that have high amino acid identities within different family members. In the present study, we identify four amino acids (Asp70, Phe73, Glu74, and Gly76 that are essential for the transport function of OATP1B1, an OATP member that is specifically expressed in the human liver. A substitution of these four amino acids with alanine resulted in significantly reduced transport activity. Further mutagenesis showed the charged property of Asp70 and Glu74 is critical for proper function of the transporter protein. Comparison of the kinetic parameters indicated that Asp70 is likely to interact with the substrate while Glu74 may be involved in stabilizing the binding site through formation of a salt-bridge. The aromatic ring structure of Phe73 seems to play an important role because substitution of Phe73 with tyrosine, another amino acid with a similar structure, led to partially restored transport function. On the other hand, replacement of Gly76 with either alanine or valine could not recover the function of the transporter. Considering the nature of a transmembrane helix, we proposed that Gly76 may be important for maintaining the proper structure of the protein. Interestingly, when subjected to transport function analysis of higher concentration of esteone-3-sulfate (50 µM that corresponds to the low affinity binding site of OATP1B1, mutants of Phe73, Glu74, and Gly76 all showed a transport function that is comparable to that of the wild-type, suggesting these amino acids may have less impact on the low affinity component of esteone-3-sulfate within OATP1B1, while Asp 70 seems to be involved in the interaction of both sites.

  11. A family of microbial lysine transporter polypeptides

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention provides a genetically modified microbial cell for production of lysine, comprising a transgene encoding a polypeptide capable of exporting lysine from the cell. The genetically modified microbial cell for production of lysine may be further characterized by genetic modifica......The present invention provides a genetically modified microbial cell for production of lysine, comprising a transgene encoding a polypeptide capable of exporting lysine from the cell. The genetically modified microbial cell for production of lysine may be further characterized by genetic...... a novel family of lysine transporter polypeptides; and the use of said polypeptide to enhance production of extracellular lysine in a microbial cell....

  12. Organic Anion-Transporting Polypeptide (OATP)-Mediated Drug-Drug Interaction Study between Rosuvastatin and Cyclosporine A in Chimeric Mice with Humanized Liver.

    Science.gov (United States)

    Uchida, Masashi; Tajima, Yoriko; Kakuni, Masakazu; Kageyama, Yutaka; Okada, Taro; Sakurada, Eri; Tateno, Chise; Hayashi, Ryoji

    2018-01-01

    The influence of transporters on the pharmacokinetics of drugs is being increasingly recognized, and DDIs via transporters may be a risk factor for adverse events. Cyclosporine A, a strong OATP inhibitor, has been reported to increase the systemic exposure of rosuvastatin, an OATP substrate, by 7.1-fold in clinical studies. PXB mice are chimeric mice with humanized livers that are highly repopulated with human hepatocytes and have been widely used for drug discovery in drug metabolism and pharmacokinetics studies. In the present study, we examined in vivo and in vitro DDIs between rosuvastatin and cyclosporine A in PXB mice and fresh human hepatocytes (PXB cells) obtained from PXB mice. We initially investigated the active transport of rosuvastatin into PXB cells, and found concentration-dependent uptake with a Michaelis-Menten constant value of 4.0 μ mol/l and a V max value of 4.63 pmol/min per 10 6 cells. Cyclosporine A inhibited the uptake of rosuvastatin with an IC 50 value of 0.21 μ mol/l. We then examined in vivo DDIs, and the exposure of orally administered rosuvastatin increased by 3.3-fold and 11-fold in PXB mice pretreated with 10 and 50 mg/kg cyclosporine A, whereas it increased by 2.5-fold and 6.2-fold when rosuvastatin was administered intravenously, in studies that were conducted for considering gastrointestinal DDIs. The liver-to-blood concentration ratio of rosuvastatin was dose-dependently decreased by pretreatment with cyclosporine A in PXB mice and SCID mice. Observed DDIs in vivo were considered to be reasonable based on the estimated concentrations of cyclosporine A at the inlet to the liver and in the liver tissues of both mice. In conclusion, our results indicate that PXB mice might be a useful tool for predicting human OATP-mediated DDIs in drug discovery, and its limitation due to the differences of gastrointestinal condition from human should also be considered. Copyright © 2017 by The American Society for Pharmacology and Experimental

  13. Anion and pH-dependent conformational transition of an amphiphilic polypeptide.

    Science.gov (United States)

    Goto, Y; Aimoto, S

    1991-03-20

    While several proteins, including beta-lactamase, cytochrome c and apomyoglobin, are maximally unfolded at pH 2 by HCl in the absence of salt, the addition of anions, either from salt or acid, co-operatively induces the unfolded proteins to refold to a molten globule state, because anions bind preferentially to the compact molten globule state compared to the extended unfolded state. To study the role of the anion-dependent conformational transition at neutral pH, we synthesized a model polypeptide of 51 amino acid residues, consisting of tandem repeats of a Lys-Lys-Leu-Leu sequence and containing a turn sequence, Asn-Pro-Gly, at the center of the molecule. The model polypeptide showed no significant conformation by circular dichroism under conditions of low salt at neutral pH. However, addition of anions, either from salt or acid, induced the folding transition to an alpha-helical conformational state. The order of effectiveness of various anions in inducing the folding transition was consistent with the series of anions in inducing the molten globule of the acid-denatured protein. This suggests that the helical state of the model polypeptide is equivalent to the molten globule state. At pH values above 9, the model polypeptide also took an alpha-helical conformation, which was very similar to that induced by anions. On the basis of the chloride and pH-dependent conformational transitions, a phase diagram for the conformational states was constructed. The phase diagram was explained simply by assuming that the conformational transition is linked to the proton and the anion bindings to a limited number of amino groups and that anions bind only to the protonated groups.

  14. [Exploring the Correlation between Pi and Shen from the Excretion of AA-I and Expressions of Or- ganic Anion Transporting Polypeptide 2al and 2 b1 in Pi Deficiency Model Rats].

    Science.gov (United States)

    Xiang, Ting; Ren, Bin; Yang, Zhang-bin; Sun, Bao-guo; Chen, Ze-xiong; Chen, Yan; Zhang, Shi-jun

    2015-10-01

    To explore the correlation between Pi and Shen by observing the relationship between the metabolism of aristolochic acid (AA) and mRNA and protein expression levels of organic anion transporting polypeptide (oatp) superfamily member 2a1 and 2 b1 (oatp2al and oatp2bl) in renal, small intestinal, and large intestinal tissues of Pi deficiency syndrome (PDS) model rats. Totally 46 Sprague-Dawley (SD) rats were randomly divided into four groups, i.e., the blank group (n = 12), the PDS group (n = 22), the AA-I group (n = 6), and the PDS AA-I group (n = 6). PDS model was established by subcutaneously injecting Reserpine at the daily dose of 5 mg/kg for 16 successive days. Carotid intubation was performed in 6 rats selected from the blank group and the PDS group. Pharmacokinetics of AA-I were detected at 5, 15, 30, 45, and 60 min after gastrogavage of AA-I. AA-I concentrations in renal, small intestinal, and large intestinal tissues of 10 rats selected from the PDS group were determined. Normal saline was administered to 6 rats selected from the PDS group and the blank group by gastrogavage. Renal, small intestinal, and large intestinal tissues were collected in the AA-I group and the PDS AA-I group at 60 min after gastrogavage of AA-I. mRNA and protein expression levels of oatp2a1 and oatp2b1 in each tissue were detected using real-time polymerase chain reaction (RT- PCR) and Western blot. Compared with the blank group, plasma concentrations of in vivo AA-I were obviously higher in the PDS group at 15, 30, 45, and 60 min after gastrogavage of AA-I with statistical difference (P AA-I were obviously decreased at 60 min after gastrogavage of AA-I; AA-I concentrations in renal and large intestinal tissues were elevated; AA-I concentrations in small intestinal tissues were obviously reduced in the PDS group. There was no statistical difference in mRNA expression levels of oatp2a1 and oatp2b1 in the aforesaid three tissues of rats between the blank group and the PDS group

  15. Ochratoxin A transport by the human breast cancer resistance protein (BCRP), multidrug resistance protein 2 (MRP2), and organic anion-transporting polypeptides 1A2, 1B1 and 2B1.

    Science.gov (United States)

    Qi, Xiaozhe; Wagenaar, Els; Xu, Wentao; Huang, Kunlun; Schinkel, Alfred H

    2017-08-15

    Ochratoxin A (OTA) is a fungal secondary metabolite that can contaminate various foods. OTA has several toxic effects like nephrotoxicity, hepatotoxicity, and neurotoxicity in different animal species, but its mechanisms of toxicity are still unclear. How OTA accumulates in kidney, liver, and brain is as yet unknown, but transmembrane transport proteins are likely involved. We studied transport of OTA in vitro, using polarized MDCKII cells transduced with cDNAs of the efflux transporters mouse (m)Bcrp, human (h)BCRP, mMrp2, or hMRP2, and HEK293 cells overexpressing cDNAs of the human uptake transporters OATP1A2, OATP1B1, OATP1B3, or OATP2B1 at pH7.4 and 6.4. MDCKII-mBcrp cells were more resistant to OTA toxicity than MDCKII parental and hBCRP-transduced cells. Transepithelial transport experiments showed some apically directed transport by MDCKII-mBcrp cells at pH7.4, whereas both mBcrp and hBCRP clearly transported OTA at pH6.4. There was modest transport of OTA by mMrp2 and hMRP2 only at pH6.4. OATP1A2 and OATP2B1 mediated uptake of OTA both at pH7.4 and 6.4, but OATP1B1 only at pH7.4. There was no detectable transport of OTA by OATP1B3. Our data indicate that human BCRP and MRP2 can mediate elimination of OTA from cells, thus reducing OTA toxicity. On the other hand, human OATP1A2, OATP1B1, and OATP2B1 can mediate cellular uptake of OTA, which could aggravate OTA toxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Polyspecific drug and steroid clearance by an organic anion transporter of mammalian liver

    NARCIS (Netherlands)

    Bossuyt, [No Value; Muller, M; Hagenbuch, B; Meier, PJ

    An organic anion-transporting polypeptide that mediates sodium-independent uptake of negatively charged sulfobromophthalein and bile salts has recently been cloned from rat liver (Jacquemin et al., 1994). In this study we have extended the substrate specificity studies to neutral and positively

  17. Anion transport and GABA signaling

    Directory of Open Access Journals (Sweden)

    Christian Andreas Huebner

    2013-10-01

    Full Text Available Whereas activation of GABAA receptors by GABA usually results in a hyperpolarizing influx of chloride into the neuron, the reversed chloride driving force in the immature nervous system results in a depolarizing efflux of chloride. This GABAergic depolarization is deemed to be important for the maturation of the neuronal network. The concept of a developmental GABA switch has mainly been derived from in vitro experiments and reliable in vivo evidence is still missing. As GABAA receptors are permeable for both chloride and bicarbonate, the net effect of GABA also critically depends on the distribution of bicarbonate. Whereas chloride can either mediate depolarizing or hyperpolarizing currents, bicarbonate invariably mediates a depolarizing current under physiological conditions. Intracellular bicarbonate is quickly replenished by cytosolic carbonic anhydrases. Intracellular bicarbonate levels also depend on different bicarbonate transporters expressed by neurons. The expression of these proteins is not only developmentally regulated but also differs between cell types and even subcellular regions. In this review we will summarize current knowledge about the role of some of these transporters for brain development and brain function.

  18. Interactions between organic anions on multiple transporters in Caco-2 cells

    DEFF Research Database (Denmark)

    Grandvuinet, Anne Sophie; Steffansen, Bente

    2011-01-01

    Caco-2 cell line may be used as an overall model to predict interactions on multiple membrane transporters in the intestine. Taurocholic acid (TCA) and estrone-3-sulfate (E1S) were used as model substrates. Possible inhibitors studied were TCA, E1S, taurolithocholic acid, fluvastatin, and glipizide......-dependent bile acid transporter and the organic solute transporter α/β, and to less extent by the organic anion transporting polypeptide 2B1. However, interactions on efflux transporters were not detected, although they were expected from the literature on the investigated compounds. Biosimulation methods may...

  19. Studies on the role of insect hemolymph polypeptides: Galleria mellonella anionic peptide 2 and lysozyme.

    Science.gov (United States)

    Sowa-Jasiłek, Aneta; Zdybicka-Barabas, Agnieszka; Stączek, Sylwia; Wydrych, Jerzy; Mak, Paweł; Jakubowicz, Teresa; Cytryńska, Małgorzata

    2014-03-01

    The lysozymes are well known antimicrobial polypeptides exhibiting antibacterial and antifungal activities. Their antibacterial potential is related to muramidase activity and non-enzymatic activity resembling the mode of action of cationic defense peptides. However, the mechanisms responsible for fungistatic and/or fungicidal activity of lysozyme are still not clear. In the present study, the anti-Candida albicans activity of Galleria mellonella lysozyme and anionic peptide 2 (AP2), defense factors constitutively present in the hemolymph, was examined. The lysozyme inhibited C. albicans growth in a dose-dependent manner. The decrease in the C. albicans survival rate caused by the lysozyme was accompanied by a considerable reduction of the fungus metabolic activity, as revealed by LIVE/DEAD staining. In contrast, although AP2 reduced C. albicans metabolic activity, it did not influence its survival rate. Our results suggest fungicidal action of G. mellonella lysozyme and fungistatic activity of AP2 toward C. albicans cells. In the presence of AP2, the anti-C. albicans activity of G. mellonella lysozyme increased. Moreover, when the fungus was incubated with both defense factors, true hyphae were observed besides pseudohyphae and yeast-like C. albicans cells. Atomic force microscopy analysis of the cells exposed to the lysozyme and/or AP2 revealed alterations in the cell surface topography and properties in comparison with the control cells. The results indicate synergistic action of G. mellonella AP2 and lysozyme toward C. albicans. The presence of both factors in the hemolymph of naive larvae suggests their important role in the early stages of immune response against fungi in G. mellonella. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. The role of organic anion transporters in diagnosing liver diseases by magnetic resonance imaging.

    Science.gov (United States)

    Pastor, Catherine M; Müllhaupt, Beat; Stieger, Bruno

    2014-04-01

    The expression and transport functions of organic anion transporters are modified in liver diseases, and therefore the vascular clearances of endogenous and exogenous organic anions that are taken up by these transporters have been used to assess liver diseases in patients. More recently, liver imaging with hepatobiliary contrast agents, tracers, and dyes that cross hepatocytes through the organic anion transporting polypeptides (OATPs)-multidrug resistance-associated proteins (MRPs) pathway were developed to detect and characterize focal lesions and to assess the severity of diffuse liver diseases. This review focuses mainly on magnetic resonance imaging and highlights the growing interest in imaging the OATPs-MRP2 pathway to better understand liver diseases. Imaging provides noninvasive measurements of tissue concentrations that result from the interplay between influx and efflux membrane transport systems in normal or injured hepatocytes. Imaging with magnetic resonance hepatobiliary contrast agents improves the detection and the characterization of hepatic focal lesions. New developments of imaging to assess liver function and understand the hepatocellular concentrations of contrast agents are discussed.

  1. Two independent anion transport systems in rabbit mandibular salivary glands

    DEFF Research Database (Denmark)

    Novak, I; Young, J A

    1986-01-01

    Cholinergically stimulated Cl and HCO3 transport in perfused rabbit mandibular glands has been studied with extracellular anion substitution and administration of transport inhibitors. In glands perfused with HCO3-free solutions, replacement of Cl with other anions supported secretion in the foll......Cholinergically stimulated Cl and HCO3 transport in perfused rabbit mandibular glands has been studied with extracellular anion substitution and administration of transport inhibitors. In glands perfused with HCO3-free solutions, replacement of Cl with other anions supported secretion...... stimulated secretion by about 30%, but when infused in addition to furosemide (0.1 mmol/l), it inhibited by about 20%. Amiloride (1.0 mmol/l) caused no inhibition. The results suggest that there are at least three distinct carriers in the rabbit mandibular gland. One is a furosemide-sensitive Na-coupled Cl...

  2. Modelling the transport of carbonic acid anions through anion-exchange membranes

    International Nuclear Information System (INIS)

    Nikonenko, V.; Lebedev, K.; Manzanares, J.A.; Pourcelly, G.

    2003-01-01

    Electrodiffusion of carbonate and bicarbonate anions through anion-exchange membranes (AEM) is described on the basis of the Nernst-Planck equations taking into account coupled hydrolysis reactions in the external diffusion boundary layers (DBLs) and internal pore solution. The model supposes local electroneutrality as well as chemical and thermodynamic equilibrium. The transport is considered in three layers being an anion exchange membrane and two adjoining diffusion layers. A mechanism of competitive transport of HCO 3 - and CO 3 2- anions through the membrane which takes into account Donnan exclusion of H + ions is proposed. It is predicted that the pH of the depleting solution decreases and that of the concentrating solution increases during electrodialysis (ED). Eventual deviations from local electroneutrality and local chemical equilibrium are discussed

  3. The inhibitory effects of five alkaloids on the substrate transport mediated through human organic anion and cation transporters.

    Science.gov (United States)

    Shams, Tahiatul; Lu, Xiaoxi; Zhu, Ling; Zhou, Fanfan

    2018-02-01

    1. Human solute carrier transporters (SLCs) are important membrane proteins mediate the cellular transport of many endogenous and exogenous substances. Organic anion/cation transporters (OATs/OCTs) and organic anion transporting polypeptides (OATPs) are essential SLCs involved in drug influx. Drug-drug/herb interactions through competing for specific SLCs often lead to unsatisfied therapeutic outcomes and/or unwanted side effects. In this study, we comprehensively investigated the inhibitory effects of five clinically relevant alkaloids (dendrobine, matrine, oxymatrine, tryptanthrin and chelerythrine) on the substrate transport through several OATs/OCTs and OATPs. 2. We performed transport functional assay and kinetic analysis on the HEK-293 cells over-expressing each SLC gene. 3. Our data showed tryptanthrin significantly inhibited the transport activity of OAT3 (IC 50  = 0.93 ± 0.22 μM, K i  = 0.43 μM); chelerythrine acted as a potent inhibitor to the substrate transport mediated through OATP1A2 (IC 50  = 0.63 ± 0.43 μM, K i  = 0.60 μM), OCT1 (IC 50  = 13.60 ± 2.81 μM) and OCT2 (IC 50  =10.80 ± 1.16 μM). 4. Our study suggested tryptanthrin and chelerythrine could potently impact on the drug transport via specific OATs/OCTs. Therefore, the co-administration of these alkaloids with drugs could have clinical consequences due to drug-drug/herb interactions. Precautions should be warranted in the multi-drug therapies involving these alkaloids.

  4. The organic anion transport inhibitor probenecid increases brain concentrations of the NKCC1 inhibitor bumetanide.

    Science.gov (United States)

    Töllner, Kathrin; Brandt, Claudia; Römermann, Kerstin; Löscher, Wolfgang

    2015-01-05

    Bumetanide is increasingly being used for experimental treatment of brain disorders, including neonatal seizures, epilepsy, and autism, because the neuronal Na-K-Cl cotransporter NKCC1, which is inhibited by bumetanide, is implicated in the pathophysiology of such disorders. However, use of bumetanide for treatment of brain disorders is associated with problems, including poor brain penetration and systemic adverse effects such as diuresis, hypokalemic alkalosis, and hearing loss. The poor brain penetration is thought to be related to its high ionization rate and plasma protein binding, which restrict brain entry by passive diffusion, but more recently brain efflux transporters have been involved, too. Multidrug resistance protein 4 (MRP4), organic anion transporter 3 (OAT3) and organic anion transporting polypeptide 2 (OATP2) were suggested to mediate bumetanide brain efflux, but direct proof is lacking. Because MRP4, OAT3, and OATP2 can be inhibited by probenecid, we studied whether this drug alters brain levels of bumetanide in mice. Probenecid (50 mg/kg) significantly increased brain levels of bumetanide up to 3-fold; however, it also increased its plasma levels, so that the brain:plasma ratio (~0.015-0.02) was not altered. Probenecid markedly increased the plasma half-life of bumetanide, indicating reduced elimination of bumetanide most likely by inhibition of OAT-mediated transport of bumetanide in the kidney. However, the diuretic activity of bumetanide was not reduced by probenecid. In conclusion, our study demonstrates that the clinically available drug probenecid can be used to increase brain levels of bumetanide and decrease its elimination, which could have therapeutic potential in the treatment of brain disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Regorafenib is transported by the organic anion transporter 1B1 and the multidrug resistance protein 2.

    Science.gov (United States)

    Ohya, Hiroki; Shibayama, Yoshihiko; Ogura, Jiro; Narumi, Katsuya; Kobayashi, Masaki; Iseki, Ken

    2015-01-01

    Regorafenib is a small molecule inhibitor of tyrosine kinases, and has been shown to improve the outcomes of patients with advanced colorectal cancer and advanced gastrointestinal stromal tumors. The transport profiles of regorafenib by various transporters were evaluated. HEK293/organic anion transporting polypeptide 1B1 (OATP1B1) cells exhibited increased drug sensitivity to regorafenib. Regorafenib inhibited the uptake of 3H-estrone sulfate by HEK293/OATP1B1 cells in a dose-dependent manner, but did not affect its elimination by P-glycoproteins. The concentration of regorafenib was significantly lower in LLC-PK1/multidrug resistance protein 2 (MRP2) cells than in LLC-PK1 cells treated with the MRP2 inhibitor, MK571. MK571 abolished the inhibitory effects of regorafenib on intracellular accumulation in LLC-PK1/MRP2 cells. The uptake of regorafenib was significantly higher in HEK293/OATP1B1 cells than in OATP1B1-mock cells. Transport kinetics values were estimated to be Km=15.9 µM and Vmax=1.24 nmol/mg/min. No significant difference was observed in regorafenib concentrations between HEK293/OATP1B3 and OATP1B3-mock cells. These results indicated that regorafenib is a substrate for MRP2 and OATP1B1, and also suggest that the substrate preference of regorafenib may implicate the pharmacokinetic profiles of regorafenib.

  6. Enzymatic methylation of band 3 anion transporter in intact human erythrocytes

    International Nuclear Information System (INIS)

    Lou, L.L.; Clarke, S.

    1987-01-01

    Band 3, the anion transport protein of erythrocyte membranes, is a major methyl-accepting substrate of the intracellular erythrocyte protein carboxyl methyltransferase (S-adenosyl-L-methionine: protein-D-aspartate O-methyltransferase; EC 2.1.1.77). The localization of methylation sites in intact cells by analysis of proteolytic fragments indicated that sites were present in the cytoplasmic N-terminal domain as well as the membranous C-terminal portion of the polypeptide. The amino acid residues that serve as carboxyl methylation sites of the erythrocyte anion transporter were also investigated. 3 H-Methylated band 3 was purified from intact erythrocytes incubated with L-[methyl- 3 H]methionine and from trypsinized and lysed erythrocytes incubated with S-adenosyl-L-[methyl- 3 H]methionine. After proteolytic digestion with carboxypeptidase Y, D-aspartic acid beta-[ 3 H]methyl ester was isolated in low yields (9% and 1%, respectively) from each preparation. The bulk of the radioactivity was recovered as [ 3 H]methanol, and the amino acid residue(s) originally associated with these methyl groups could not be determined. No L-aspartic acid beta-[ 3 H]methyl ester or glutamyl gamma-[ 3 H]methyl ester was detected. The formation of D-aspartic acid beta-[ 3 H]methyl esters in this protein in intact cells resulted from protein carboxyl methyltransferase activity since it was inhibited by adenosine and homocysteine thiolactone, which increases the intracellular concentration of the potent product inhibitor S-adenosylhomocysteine, and cycloleucine, which prevents the formation of the substrate S-adenosyl-L-[methyl- 3 H]methionine

  7. Ternary Complexation on Bacterial Surfaces: Implications for Subsurface Anion Transport

    Science.gov (United States)

    Maclean, L. C.; Higginbottom, C. M.; Fowle, D. A.

    2002-12-01

    The physical, chemical, and biological controls on contaminant mobilities in aquatic ecosystems must be determined to establish the threat that contamination poses to the environment. Quantitative models of contaminant mobilities are required as a prerequisite to guide remediation efforts and to prioritize the potential hazard to the ecosystem of each contaminated site. It is well established that mineral surface adsorption is an important control on contaminant mobilities, and many studies have utilized thermodynamics to quantify metal/organic adsorption in order to yield predictive models of contaminant transport. However, these models of contaminant transport may not be representative of the reactions which control contaminant mobilities as most mineral surfaces are coated with organic acids, bacteria, and extracellular polymers. Numerous laboratory studies have demonstrated that bacterial cell walls have a high affinity for binding metal cations, and field studies indicate that a significant proportion of bacteria cells and associated extracellular matrices are coated with small scale hydrous metal oxides. The small size of bacteria, and in many cases the nanoscale of their associated mineral phases, suggests these bacteria-mineral composites may represent a large proportion of surface area exposed to fluid flow. Therefore, due to the affinity of bacterial cell walls for cations and biominerals, bacteria may also have a significant impact on anionic contaminant mobility in many natural systems. The extent of metal-bacteria adsorption reactions varies drastically as a function of pH and solution chemistry. Current adsorption models have focused on the interactions of positively charged metal cations with bacterial surfaces, however in many oxidizing environments metals such as Cr exist as anions or anionic complexes. We have studied the ability of non-metabolizing cells of the bacterial species Bacillus subtilis and Shewanella putrifaciens to adsorb aqueous Cr

  8. Renal organic anion transport: a comparative and cellular perspective.

    Science.gov (United States)

    Dantzler, William H

    2002-11-13

    A major system for net transepithelial secretion of a wide range of hydrophobic organic anions (OAs) exists in the proximal renal tubules of almost all vertebrates. This process involves transport into the cells against an electrochemical gradient at the basolateral membrane and movement from the cells into the lumen down an electrochemical gradient. Transport into the cells at the basolateral membrane, which is the dominant, rate-limiting step, is a tertiary active transport process, the final step which involves countertransport of the OA into the cells against its electrochemical gradient in exchange for alpha-ketoglutarate moving out of the cells down its electrochemical gradient. The outwardly directed gradient for alpha-ketoglutarate is maintained by metabolism ( approximately 40%) and by transport into the cells across both the basolateral and luminal membranes by separate sodium-dicarboxylate cotransporters ( approximately 60%). The inwardly directed sodium gradient driving alpha-ketoglutarate uptake is maintained by the basolateral Na(+)-K(+)-ATPase, the primary energy-requiring transport step in the total tertiary process. The basolateral OA/alpha-ketoglutarate exchange process now appears to be physiologically regulated by several factors in mammalian tubules, including peptide hormones (e.g., bradykinin) and the autonomic nervous system acting via protein kinase C (PKC) pathways and epidermal growth factor (EGF) working via the mitogen-activated protein kinase (MAPK) pathway.

  9. Regulation of renal peripheral benzodiazepine receptors by anion transport inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Basile, A.S.; Lueddens, W.M.; Skolnick, P.

    1988-01-01

    The in vitro and in vivo regulation of (/sup 3/H)Ro 5-4864 binding to peripheral benzodiazepine receptors (PBR) by ion transport/exchange inhibitors was studied in the kidney. The potencies of 9-anthroic acid, furosemide, bumetanide, hydrochlorothiazide and SITS as inhibitors of (/sup 3/H)Ro 5-4864 binding to renal membranes were consistent with their actions as anion transport inhibitors (Ki approx. = 30 - 130 ..mu..M). In contrast, spironolactone, amiloride, acetazolamide, and ouabain were less potent (Ki=100-1000 ..mu..M). Administration of furosemide to rats for five days resulted in a profound diuresis accompanied by a significant increase in PBR density (43%) that was apparent by the fifth day of treatment. Administration of hydrochlorothiazide or Ro 5-4864 for five days also caused diuresis and increased renal PBR density. Both the diuresis and increased density of PBR produced by Ro 5-4864 were blocked by coadministration of PK 11195, which alone had no effect on either PBR density or urine volume. The equilibrium binding constants of (/sup 3/H)Ro 5-4864 to cardiac membranes were unaffected by administration of any of these drugs. These findings suggest that renal PBR may be selectively modulated in vivo and in vitro by administration of ion transport/exchange inhibitors. 36 references, 4 tables.

  10. The Organic Anion Transporter (OAT) Family: A Systems Biology Perspective

    Science.gov (United States)

    Nigam, Sanjay K.; Bush, Kevin T.; Martovetsky, Gleb; Ahn, Sun-Young; Liu, Henry C.; Richard, Erin; Bhatnagar, Vibha; Wu, Wei

    2015-01-01

    The organic anion transporter (OAT) subfamily, which constitutes roughly half of the SLC22 (solute carrier 22) transporter family, has received a great deal of attention because of its role in handling of common drugs (antibiotics, antivirals, diuretics, nonsteroidal anti-inflammatory drugs), toxins (mercury, aristolochic acid), and nutrients (vitamins, flavonoids). Oats are expressed in many tissues, including kidney, liver, choroid plexus, olfactory mucosa, brain, retina, and placenta. Recent metabolomics and microarray data from Oat1 [Slc22a6, originally identified as NKT (novel kidney transporter)] and Oat3 (Slc22a8) knockouts, as well as systems biology studies, indicate that this pathway plays a central role in the metabolism and handling of gut microbiome metabolites as well as putative uremic toxins of kidney disease. Nuclear receptors and other transcription factors, such as Hnf4α and Hnf1α, appear to regulate the expression of certain Oats in conjunction with phase I and phase II drug metabolizing enzymes. Some Oats have a strong selectivity for particular signaling molecules, including cyclic nucleotides, conjugated sex steroids, odorants, uric acid, and prostaglandins and/or their metabolites. According to the “Remote Sensing and Signaling Hypothesis,” which is elaborated in detail here, Oats may function in remote interorgan communication by regulating levels of signaling molecules and key metabolites in tissues and body fluids. Oats may also play a major role in interorganismal communication (via movement of small molecules across the intestine, placental barrier, into breast milk, and volatile odorants into the urine). The role of various Oat isoforms in systems physiology appears quite complex, and their ramifications are discussed in the context of remote sensing and signaling. PMID:25540139

  11. Synthetic ion transporters can induce apoptosis by facilitating chloride anion transport into cells.

    Science.gov (United States)

    Ko, Sung-Kyun; Kim, Sung Kuk; Share, Andrew; Lynch, Vincent M; Park, Jinhong; Namkung, Wan; Van Rossom, Wim; Busschaert, Nathalie; Gale, Philip A; Sessler, Jonathan L; Shin, Injae

    2014-10-01

    Anion transporters based on small molecules have received attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis. However, a direct correlation between a change in cellular chloride anion concentration and cytotoxicity has not been established for synthetic ion carriers. Here we show that two pyridine diamide-strapped calix[4]pyrroles induce coupled chloride anion and sodium cation transport in both liposomal models and cells, and promote cell death by increasing intracellular chloride and sodium ion concentrations. Removing either ion from the extracellular media or blocking natural sodium channels with amiloride prevents this effect. Cell experiments show that the ion transporters induce the sodium chloride influx, which leads to an increased concentration of reactive oxygen species, release of cytochrome c from the mitochondria and apoptosis via caspase activation. However, they do not activate the caspase-independent apoptotic pathway associated with the apoptosis-inducing factor. Ion transporters, therefore, represent an attractive approach for regulating cellular processes that are normally controlled tightly by homeostasis.

  12. Modulatory effects of hormones, drugs, and toxic events on renal organic anion transport.

    NARCIS (Netherlands)

    Terlouw, S.A.; Masereeuw, R.; Russel, F.G.M.

    2003-01-01

    The human body is exposed continuously to a wide variety of exogenous compounds, many of which are anionic compounds. In addition, products of phase II biotransformation reactions are negatively charged, viz. glucuronides, sulfate esters, or glutathiones. Renal transport of organic anions is an

  13. The role of the canalicular multispecific organic anion transporter in the disposal of endo- and xenobiotics

    NARCIS (Netherlands)

    Oude Elferink, R. P.; Jansen, P. L.

    1994-01-01

    Bile is an important excretory route for the elimination of amphiphilic organic anions, and hepatocytes are the primary secretory units of bile formation. The hepatocytic basolateral and canalicular membranes are equipped with various carrier proteins. Transport across the canalicular membrane

  14. THE ROLE OF THE CANALICULAR MULTISPECIFIC ORGANIC ANION TRANSPORTER IN THE DISPOSAL OF ENDOBIOTICS AND XENOBIOTICS

    NARCIS (Netherlands)

    ELFERINK, RPJO; JANSEN, PLM

    1994-01-01

    Bile is an important excretory route for the elimination of amphiphilic organic anions, and hepatocytes are the primary secretory units of bile formation. The hepatocytic basolateral and canalicular membranes are equipped with various carrier proteins. Transport across the canalicular membrane

  15. Improvement of Anion Transport Systems by Modulation of Chalcogen Interactions: The influence of solvent.

    Science.gov (United States)

    Sánchez-Sanz, Goar; Trujillo, Cristina

    2018-02-08

    A series of potential anion transporters, dithieno[3,2-b;2',3'-d]thiophenes (DTT), involving anion-chalcogen interactions have been studied by analyzing the interaction energy, geometry, and charge transfer. It was found that gas phase calculations show very negative interaction energies with short anion-chalcogen distances, but when solvent effects are considered, the interaction energy values decreased drastically concomitantly with an elongation on the interatomic distances. To enhance the chalcogen interaction between the DTT derivatives and the anion, increasing the anion transporter capacity, bisisothioazole moiety was considered; i.e., the σ-hole of the chalcogen atom was modulated by substitution of the adjacent carbon by a nitrogen atom in the S-C axis, increasing the depth of the σ-hole and therefore the interaction between the chalcogen and anion. Finally, different anions were analyzed within the complexes, finding that F - and NO 3 - would be the best candidates to form complexes and possibly displace other anions such as Cl - or Br - .

  16. Organic anion transporter (Slc22a) family members as mediators of toxicity

    International Nuclear Information System (INIS)

    Sweet, Douglas H.

    2005-01-01

    Exposure of the body to toxic organic anions is unavoidable and occurs from both intentional and unintentional sources. Many hormones, neurotransmitters, and waste products of cellular metabolism, or their metabolites, are organic anions. The same is true for a wide variety of medications, herbicides, pesticides, plant and animal toxins, and industrial chemicals and solvents. Rapid and efficient elimination of these substances is often the body's best defense for limiting both systemic exposure and the duration of their pharmacological or toxicological effects. For organic anions, active transepithelial transport across the renal proximal tubule followed by elimination via the urine is a major pathway in this detoxification process. Accordingly, a large number of organic anion transport proteins belonging to several different gene families have been identified and found to be expressed in the proximal nephron. The function of these transporters, in combination with the high volume of renal blood flow, predisposes the kidney to increased toxic susceptibility. Understanding how the kidney mediates the transport of organic anions is integral to achieving desired therapeutic outcomes in response to drug interactions and chemical exposures, to understanding the progression of some disease states, and to predicting the influence of genetic variation upon these processes. This review will focus on the organic anion transporter (OAT) family and discuss the known members, their mechanisms of action, subcellular localization, and current evidence implicating their function as a determinant of the toxicity of certain endogenous and xenobiotic agents

  17. Organic anion transporter 2 (SLC22A7) is a facilitative transporter of cGMP.

    Science.gov (United States)

    Cropp, Cheryl D; Komori, Takafumi; Shima, James E; Urban, Thomas J; Yee, Sook Wah; More, Swati S; Giacomini, Kathleen M

    2008-04-01

    The second messenger, cGMP, mediates a host of cellular responses to various stimuli, resulting in the regulation of many critical physiologic functions. The existence of specific cGMP transporters on the plasma membrane that participate in the regulation of cGMP levels has been suggested in a large number of studies. In this study, we identified a novel plasma membrane transporter for cGMP. In particular, we showed that hOAT2 (SLC22A7), a member of the solute carrier (SLC) superfamily, was a facilitative transporter for cGMP and other guanine nucleotides. hOAT2, which is ubiquitously expressed at high levels in many cell types, was previously thought to primarily transport organic anions. Among purine and pyrimidine nucleobases, nucleosides, and nucleotides, hOAT2 showed the greatest preference for cGMP, which transported cGMP with a K(m) value of 88 +/- 11 muM and exhibited between 50- and 100-fold enhanced uptake over control cells. Our data revealed that hOAT2 is a bidirectional facilitative transporter that can control both intracellular and extracellular levels of cGMP. In addition, we observed that a common alternatively spliced variant of hOAT2 demonstrated a complete loss of transport function as a result of a low expression level on the plasma membrane. We conclude that hOAT2 is a highly efficient, facilitative transporter of cGMP and may be involved in cGMP signaling in many tissues. Our study suggests that hOAT2 represents a potential new drug target for regulating cGMP levels.

  18. Flavonoids Are Inhibitors of Human Organic Anion Transporter 1 (OAT1)–Mediated Transport

    Science.gov (United States)

    An, Guohua; Wang, Xiaodong

    2014-01-01

    Organic anion transporter 1 (OAT1) has been reported to be involved in the nephrotoxicity of many anionic xenobiotics. As current clinically used OAT1 inhibitors are often associated with safety issues, identifying potent OAT1 inhibitors with little toxicity is of great value in reducing OAT1-mediated drug nephrotoxicity. Flavonoids are a class of polyphenolic compounds with exceptional safety records. Our objective was to evaluate the effects of 18 naturally occurring flavonoids, and some of their glycosides, on the uptake of para-aminohippuric acid (PAH) in both OAT1-expressing and OAT1-negative LLC-PK1 cells. Most flavonoid aglycones produced substantial decreases in PAH uptake in OAT1-expressing cells. Among the flavonoids screened, fisetin, luteolin, morin, and quercetin exhibited the strongest effect and produced complete inhibition of OAT1-mediated PAH uptake at a concentration of 50 μM. Further concentration-dependent studies revealed that both morin and luteolin are potent OAT1 inhibitors, with IC50 values of flavonoid aglycones, all flavonoid glycosides had negligible or small effects on OAT1. In addition, the role of OAT1 in the uptake of fisetin, luteolin, morin, and quercetin was investigated and fisetin was found to be a substrate of OAT1. Taken together, our results indicate that flavonoids are a novel class of OAT1 modulators. Considering the high consumption of flavonoids in the diet and in herbal products, OAT1-mediated flavonoid-drug interactions may be clinically relevant. Further investigation is warranted to evaluate the nephroprotective role of flavonoids in relation to drug-induced nephrotoxicity mediated by the OAT1 pathway. PMID:25002746

  19. Impact of the induced organic anion transporter 1 (Oat1) renal expression by furosemide on the pharmacokinetics of organic anions.

    Science.gov (United States)

    Severin, María Julia; Hazelhoff, María Herminia; Bulacio, Romina Paula; Mamprin, María Eugenia; Brandoni, Anabel; Torres, Adriana Mónica

    2017-08-01

    Furosemide is a loop diuretic. Different authors demonstrated that continuous administration of furosemide modulates the expression of organic anion transporters. This study was undertaken to simultaneously evaluate the effects of furosemide pretreatment on organic anion transporter 1 (Oat1) and multidrug resistance protein 2 (Mrp2) renal expressions, on p-aminohippurate (PAH) pharmacokinetics and on renal and urinary PAH levels in rats. Male Wistar rats were treated with furosemide (6 mg/100 g body weight per day, subcutaneously, 4 days) (treated group) or saline (control group). On the fifth day, PAH was administered as a bolus infusion in the femoral vein, and plasma samples were obtained from femoral artery at different time points. PAH levels in renal tissue and urine were also assessed. Renal Oat1 and Mrp2 expressions were evaluated by western blotting. Furosemide pretreatment increased both the expression of Oat1 and Mrp2. PAH plasma concentrations decreased following a biexponential function. The furosemide-treated group showed higher PAH plasma levels, a lower systemic clearance and elimination rate constant from the peripheral compartment, indicating that PAH renal elimination was decreased. PAH levels in renal tissue were significantly elevated and in urine appeared to be significantly lower as compared with control animals. Furosemide pretreatment caused a significant decrease of PAH renal elimination, despite Oat1 and Mrp2 augmented renal expression. The goal of the present study is the addition of important information in the wide gap of knowledge that exists about drug-drug interactions. Because of furosemide worldwide use, the data obtained are interesting and useful in terms of translation to clinical practice. © 2016 Asian Pacific Society of Nephrology.

  20. Enhanced Anion Transport Using Some Expanded Porphyrins as Carriers.

    Science.gov (United States)

    1991-01-01

    many others who provided me with invaluable and much needed help. Miguel Rosingana, Kevin Boudreaux, Micheal Cyr, Dr. Tony Burrell, and Kevin Shredder ...channel in erythrocytes; and the so-called ATP/ADP exchanger. 19 A breakdown in the mediated transport of an essential metabolqtes can be detrimental. For

  1. Elastomeric polypeptides.

    Science.gov (United States)

    van Eldijk, Mark B; McGann, Christopher L; Kiick, Kristi L; van Hest, Jan C M

    2012-01-01

    Elastomeric polypeptides are very interesting biopolymers and are characterized by rubber-like elasticity, large extensibility before rupture, reversible deformation without loss of energy, and high resilience upon stretching. Their useful properties have motivated their use in a wide variety of materials and biological applications. This chapter focuses on elastin and resilin - two elastomeric biopolymers - and the recombinant polypeptides derived from them (elastin-like polypeptides and resilin-like polypeptides). This chapter also discusses the applications of these recombinant polypeptides in the fields of purification, drug delivery, and tissue engineering.

  2. Uraemic toxins induce proximal tubular injury via organic anion transporter 1-mediated uptake

    Science.gov (United States)

    Motojima, Masaru; Hosokawa, Atsuko; Yamato, Hideyuki; Muraki, Takamura; Yoshioka, Toshimasa

    2002-01-01

    A direct effect of uraemic toxins in promoting progression of chronic renal disease has not been established. In this study, we investigated the toxic effects of organic anions which characteristically appeared in the patients with progressive renal disease on renal proximal tubular cells expressing human organic anion transporter (hOAT) 1. A renal proximal tubular cell line, opossum kidney (OK) cells, was transformed with hOAT1. Among the organic anions examined, hippuric acid, para-hydroxyhippuric acid, ortho-hydroxyhippuric acid, indoxyl sulphate and indoleacetic acid showed a high affinity for hOAT1 expressed in the OK cells. Indoxyl sulphate and indoleacetic acid concentration-dependently inhibited proliferation of the hOAT1-transformed cells. The h.p.l.c. analysis demonstrated that cellular uptake of these organic anions was significantly elevated in hOAT1-transformed cells. These organic anions also concentration-dependently stimulated cellular free radical production. The degrees of inhibition of cell proliferation and the stimulation of free radical production induced by the organic anions were significantly higher in the hOAT1-transformed cells than vector-transformed cells. The stimulatory effect of indoxyl sulphate on free radical production was abolished by anti-oxidants and probenecid. Less free radical production was observed in the hOAT1-transformed cells treated with p-hydroxyhippuric acid, o-hydroxyhippuric acid compared with indoxyl sulphate and indoleacetic acid. Hippuric acid had little effect on free radical production. Organic anions present in the serum of patients with progressive renal disease may cause proximal tubular injury via hOAT1-mediated uptake. The mechanism of cellular toxicity by these uraemic toxins involves free radical production. Thus, some uraemic toxins may directly promote progression of chronic renal disease. PMID:11815391

  3. Energy transport mechanism in the form of proton soliton in a one-dimensional hydrogen-bonded polypeptide chain.

    Science.gov (United States)

    Kavitha, L; Priya, R; Ayyappan, N; Gopi, D; Jayanthi, S

    2016-01-01

    The dynamics of protons in a one-dimensional hydrogen-bonded (HB) polypeptide chain (PC) is investigated theoretically. A new Hamiltonian is formulated with the inclusion of higher-order molecular interactions between peptide groups (PGs). The wave function of the excitation state of a single particle is replaced by a new wave function of a two-quanta quasi-coherent state. The dynamics is governed by a higher-order nonlinear Schrödinger equation and the energy transport is performed by the proton soliton. A nonlinear multiple-scale perturbation analysis has been performed and the evolution of soliton parameters such as velocity and amplitude is explored numerically. The proton soliton is thermally stable and very robust against these perturbations. The energy transport by the proton soliton is more appropriate to understand the mechanism of energy transfer in biological processes such as muscle contraction, DNA replication, and neuro-electric pulse transfer on biomembranes.

  4. Roles of organic anion transporters (OATs) in renal proximal tubules and their localization.

    Science.gov (United States)

    Otani, Naoyuki; Ouchi, Motoshi; Hayashi, Keitaro; Jutabha, Promsuk; Anzai, Naohiko

    2017-03-01

    Organic anions (OAs) are secreted in renal proximal tubules in two steps. In the first step, OAs are transported from the blood through basolateral membranes into proximal tubular cells. The prototypical substrate for renal organic anion transport systems, para-aminohippurate (PAH), is transported across basolateral membranes of proximal tubular cells via OAT1 (SLC22A6) and OAT3 (SLC22A8) against an electrochemical gradient in exchange for intracellular dicarboxylates. In the second step, OAs exit into urine through apical membranes of proximal tubules. This step is thought to be performed by multidrug efflux transporters and a voltage-driven organic anion transporter. However, the molecular nature and precise functional properties of these efflux systems are largely unknown. Recently, we characterized an orphan transporter known as human type I sodium-phosphate transporter 4, hNPT4 (SLC17A3), using the Xenopus oocyte expression system. hNPT4 acts as a voltage-driven efflux transporter ("human OATv1") for several OAs such as PAH, estrone sulfate, diuretic drugs, and urate. Here, we describe a model for an OA secretory pathway in renal tubular cells in which OAs exit cells and enter the tubular lumen via hOATv1 (hNPT4). Additionally, hOATv1 functions as a common renal secretory pathway for both urate and drugs, indicating that hOATv1 may be a leak pathway for excess urate that is reabsorbed via apical URAT1 to control the intracellular urate levels. Therefore, we propose a molecular mechanism for the induction of hyperuricemia by diuretics: the diuretics enter proximal tubular cells via basolateral OAT1 and/or OAT3 and may then interfere with the NPT4-mediated apical urate efflux in the renal proximal tubule.

  5. Effect of probenecid on the transport of methyl mercury in erythrocytes by the organic anion transport system

    Energy Technology Data Exchange (ETDEWEB)

    Wu Guang [Biochemistry Section, National Institute for Minamata Disease, Minamata, Kumamoto (Japan)

    1997-02-01

    The uptake of methyl mercury (MeHg) by isolated erythrocytes from rats was studied at 5 and 20 C. The Na{sup +} ion was used to examine exerted effects of probenecid on the uptake of MeHg through the organic anion transport system. Different extracellular pH levels were used to examine effects on the uptake of MeHg and on probenecid induced effects on the uptake of MeHg through the organic anion transport system; the effects of three anisotonic conditions were also determined. The results showed: (1) probenecid might partially change the role of Na{sup +} ion from inhibition to stimulation for the uptake of MeHg; (2) the organic anion transport system for the uptake of MeHg was pH-dependent within the physiological range of extracellular pH; (3) the organic transport system for the uptake of MeHg was independent of deformation of the erythrocyte membrane. (orig.). With 4 figs.

  6. Influence of anisotropy, anion sorption, and degree of decomposition on solute transport in peat

    Science.gov (United States)

    McCarter, C. P. R.; Rezanezhad, F.; Gharedaghloo, B.; Price, J. S.; Van Cappellen, P.

    2017-12-01

    Many permafrost regions are covered by peat dominated wetlands that govern the flow of water, nutrients, and contaminants in these landscapes. However, due to the non-linear decrease in active pore distribution, hydraulic conductivity, and anisotropy with depth from surface, solute transport processes in peat and peatlands are complex and generally poorly understood. Historically, the majority of solute transport studies in peat and peatlands rely on non-reactive chemical tracers (e.g., chloride or bromide) but the high organic content of peat creates the potential for anion sorption. Where anion sorption is possible, the conservative nature of non-reactive anion tracers may be questionable; however, conservative isotopic tracers, such as deuterated water, present the opportunity to determine whether "non-reactive" anions are truly conservative in highly organic peat soils. Given these critical gaps in our understanding, this study aims to characterize the influence of pore structure, anisotropy, and diffusion on the transport of chloride and deuterium tracers at two depths below the surface (-20 and -70 cm); representing two distinct levels of peat decomposition. The results indicate that the chloride sorption partitioning coefficient decreased with degree of decomposition, yet all levels of decomposition showed limited sorption at low concentrations (< 165 mg/L); suggesting a partial conservative behaviour of chloride in peat. However, chloride was sorbed at higher concentrations; thus, limiting its effectiveness as a conservative tracer. Horizontal dispersivity was higher than vertical at both -20 and -70 cm depths and, on average, dispersivity increased with depth suggesting a more tortuous flow path at lower depths. These results highlight that unlike hydraulic conductivity, which is typically larger horizontally than vertically, the majority of solute transport may occur in a subset of pores the hydraulically active pores.

  7. The Organic Anion-Transporting Peptide 2B1 Is Localized in the Basolateral Membrane of the Human Jejunum and Caco-2 Monolayers.

    Science.gov (United States)

    Keiser, Markus; Kaltheuner, Lars; Wildberg, Charlotte; Müller, Janett; Grube, Markus; Partecke, Lars Ivo; Heidecke, Claus-Dieter; Oswald, Stefan

    2017-09-01

    The organic anion-transporting polypeptide (OATP) 2B1 which is ubiquitously expressed in the human body is assumed to play an important role in the cellular uptake of many drugs. Although the expression and function of this solute carrier transporter is well characterized in the human liver and other tissues, little is known about its localization and functional relevance in the intestine. Thus, it was the aim of this study to investigate its localization and function in the human jejunum and in the frequently used intestinal Caco-2 cell line. The basolateral membrane of jejunal tissue from 6 individuals showed a significant enrichment of OATP2B1 (17-fold) and the known basolateral proteins ABCC3 and Na/K-ATPase compared to the apical membrane as derived from targeted proteomics analysis. On the contrary, apical localization could be confirmed for ABCB1, ABCC2, and PEPT1. Basolateral localization of OATP2B1 could also be verified in Caco-2 cells. Bidirectional transport studies with established OATP2B1 substrates (sulfasalazine and pravastatin) across freshly exercised human jejunum and Caco-2 cell monolayers demonstrated a markedly higher transport from the basal to the apical compartment than in the opposite direction. Our data provide evidence for a basolateral localization of OATP2B1 which may improve our understanding of intestinal drug absorption. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  8. Male-dominant activation of rat renal organic anion transporter 1 (Oat1 and 3 (Oat3 expression by transcription factor BCL6.

    Directory of Open Access Journals (Sweden)

    Waja Wegner

    Full Text Available BACKGROUND: Organic anion transporters 1 (Oat1 and 3 (Oat3 mediate the transport of organic anions, including frequently prescribed drugs, across cell membranes in kidney proximal tubule cells. In rats, these transporters are known to be male-dominant and testosterone-dependently expressed. The molecular mechanisms that are involved in the sex-dependent expression are unknown. Our aim was to identify genes that show a sex-dependent expression and could be involved in male-dominant regulation of Oat1 and Oat3. METHODOLOGY/PRINCIPAL FINDINGS: Promoter activities of Oat1 and Oat3 were analyzed using luciferase assays. Expression profiling was done using a SurePrint G3 rat GE 8 × 60K microarray. RNA was isolated from renal cortical slices of four adult rats per sex. To filter the achieved microarray data for genes expressed in proximal tubule cells, transcription database alignment was carried out. We demonstrate that predicted androgen response elements in the promoters of Oat1 and Oat3 are not functional when the promoters were expressed in OK cells. Using microarray analyses we analyzed 17,406 different genes. Out of these genes, 56 exhibit a sex-dependent expression in rat proximal tubule cells. As genes potentially involved in the regulation of Oat1 and Oat3 expression, we identified, amongst others, the male-dominant hydroxysteroid (17-beta dehydrogenase 1 (Hsd17b1, B-cell CLL/lymphoma 6 (BCL6, and polymerase (RNA III (DNA directed polypeptide G (Polr3g. Moreover, our results revealed that the transcription factor BCL6 activates promoter constructs of Oat1 and Oat3. CONCLUSION: The results indicate that the male-dominant expression of both transporters, Oat1 and Oat3, is possibly not directly regulated by the classical androgen receptor mediated transcriptional pathway but appears to be regulated by the transcription factor BCL6.

  9. Analogies between solitonic bio-energy transport along polypeptide chains and nonautonomous optical solitons in structurated nonuniform fibers

    Science.gov (United States)

    Morales-Lara, L.; Peña-Moreno, R.; Mena-Contla, A.; Serkin, V. N.; Belyaeva, T. L.

    2015-01-01

    The interpenetration of the main ideas and methods being used in different fields of science and technology has become one of the decisive factors in the progress of science as a whole. Mathematical analogies between different physical systems can be extremely fruitful in understanding the novel physical concepts. Accordingly to the new theory of bio-energy transport along protein molecules in living systems and modified Davydov molecular soliton theory, we propose a nonautonomous model that can be considered as a candidate of the bio-energy transport mechanism in protein molecules. Based on the generalized nonlinear Schrödinger equation model with varying-intime harmonic oscillator potential, we show that conditions of its exact integrability in one-dimensional case indicate conclusively the way for solitonlike pulse generation in polypeptide molecular systems. The most important properties of this soliton transport of bio-energy are related with periodically changed energy-release conditions and the influences of structure nonuniformity in protein molecules. By analogy with the corresponding optical phenomena in inhomogeneous optical fibers with varying properties along the length, we study the main features of modified Davydov soliton on the basis of the unified nonautonomous nonlinear Schrodinger model in the parameters region of the exact integrability of the model under consideration.

  10. Multi-functional roles for the polypeptide transport associated domains of Toc75 in chloroplast protein import

    Science.gov (United States)

    Paila, Yamuna D; Richardson, Lynn GL; Inoue, Hitoshi; Parks, Elizabeth S; McMahon, James; Inoue, Kentaro; Schnell, Danny J

    2016-01-01

    Toc75 plays a central role in chloroplast biogenesis in plants as the membrane channel of the protein import translocon at the outer envelope of chloroplasts (TOC). Toc75 is a member of the Omp85 family of bacterial and organellar membrane insertases, characterized by N-terminal POTRA (polypeptide-transport associated) domains and C-terminal membrane-integrated β-barrels. We demonstrate that the Toc75 POTRA domains are essential for protein import and contribute to interactions with TOC receptors, thereby coupling preprotein recognition at the chloroplast surface with membrane translocation. The POTRA domains also interact with preproteins and mediate the recruitment of molecular chaperones in the intermembrane space to facilitate membrane transport. Our studies are consistent with the multi-functional roles of POTRA domains observed in other Omp85 family members and demonstrate that the domains of Toc75 have evolved unique properties specific to the acquisition of protein import during endosymbiotic evolution of the TOC system in plastids. DOI: http://dx.doi.org/10.7554/eLife.12631.001 PMID:26999824

  11. Anion complexation and transport by isophthalamide and dipicolinamide derivatives: DNA plasmid transformation in E. coli.

    Science.gov (United States)

    Atkins, Jason L; Patel, Mohit B; Daschbach, Megan M; Meisel, Joseph W; Gokel, George W

    2012-08-22

    Tris-arenes based on either isophthalic acid or 2,6-dipicolinic acid have been known for more than a decade to bind anions. Recent studies have also demonstrated their ability to transport various ions through membranes. In this report, we demonstrate two important properties of these simple diamides. First, they transport plasmid DNA into Escherichia coli about 2-fold over controls, where the ampicillin resistance gene is expressed in the bacteria. These studies were done with plasmid DNA (~2.6 kilobase (kb)) in JM109 E. coli cells. Second, known methods do not typically transport large plasmids (>15 kb). We demonstrate here that transformation of large pVIB plasmids (i.e., >20 kb) were enhanced over water controls by ~10-fold. These results are in striking contrast to the normal decrease in transformation with increasing plasmid size.

  12. Targeting organic anion transporter 3 with probenecid as a novel anti-influenza a virus strategy.

    Science.gov (United States)

    Perwitasari, Olivia; Yan, Xiuzhen; Johnson, Scott; White, Caleb; Brooks, Paula; Tompkins, S Mark; Tripp, Ralph A

    2013-01-01

    Influenza A virus infection is a major global health concern causing significant mortality, morbidity, and economic loss. Antiviral chemotherapeutics that target influenza A virus are available; however, rapid emergence of drug-resistant strains has been reported. Consequently, there is a burgeoning need to identify novel anti-influenza A drugs, particularly those that target host gene products required for virus replication, to reduce the likelihood of drug resistance. In this study, a small interfering RNA (siRNA) screen was performed to identify host druggable gene targets for anti-influenza A virus therapy. The host organic anion transporter-3 gene (OAT3), a member of the SLC22 family of transporters, was validated as being required to support influenza A virus replication. Probenecid, a prototypical uricosuric agent and chemical inhibitor of organic anion transporters known to target OAT3, was shown to be effective in limiting influenza A virus infection in vitro (50% inhibitory concentration [IC(50)] of 5.0 × 10(-5) to 5.0 × 10(-4) μM; P Probenecid is widely used for treatment of gout and related hyperuricemic disorders, has been extensively studied for pharmacokinetics and safety, and represents an excellent candidate for drug repositioning as a novel anti-influenza A chemotherapeutic.

  13. Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy

    KAUST Repository

    Geise, Geoffrey M.

    2013-09-17

    Many salinity gradient energy technologies such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange membranes. While there is considerable interest in using thermolytic solutions such as ammonium bicarbonate (AmB) in RED processes for closed-loop conversion of heat energy to electricity, little is known about membrane performance in this electrolyte. The resistances of two commercially available cation exchange membranes in AmB were lower than their resistances in NaCl. However, the resistances of commercially available anion exchange membranes (AEMs) were much larger in AmB than in NaCl, which would adversely affect energy recovery. The properties of a series of quaternary ammonium-functionalized poly(phenylene oxide) and Radel-based AEMs were therefore examined to understand the reasons for increased resistance in AmB to overcome this performance penalty due to the lower mobility of bicarbonate, 4.59 × 10-4 cm2/(V s), compared to chloride, 7.90 × 10-4 cm2/(V s) (the dilute aqueous solution mobility ratio of HCO3 - to Cl- is 0.58). Most membrane resistances were generally consistent with the dilute solution mobilities of the anions. For a few key samples, however, increased water uptake in AmB solution reduced the ionic resistance of the polymer compared to its resistance in NaCl solution. This increased water uptake was attributed to the greater hydration of the bicarbonate ion compared to the chloride ion. The increased resistance due to the use of bicarbonate as opposed to chloride ions in AEMs can therefore be mitigated by designing polymers that swell more in AmB compared to NaCl solutions, enabling more efficient energy recovery using AmB thermolytic solutions in RED. © 2013 American Chemical Society.

  14. Role of phosphate and other proton-donating anions in respiration-coupled transport of Ca2+ by mitochondria.

    Science.gov (United States)

    Lehninger, A L

    1974-04-01

    Measurements of extra oxygen consumption, (45)Ca(2+) uptake, and the osmotic expansion of the matrix compartment show that not all permeant anions are capable of supporting and accompanying the energy-dependent transport of Ca(2+) from the medium into the matrix in respiring rat-liver mitochondria. Phosphate, arsenate, acetate, butyrate, beta-hydroxybutyrate, lactate, and bicarbonate + CO(2) supported Ca(2+) uptake, whereas the permeant anions, nitrate, thiocyanate, chlorate, and perchlorate, did not. The active anions share a common denominator, the potential ability to donate a proton to the mitochondrial matrix; the inactive anions lack this capacity. Phosphate and the other active permeant anions move into the matrix in response to the alkaline-inside electrochemical gradient of protons generated across the mitochondrial membrane by electron transport, thus forming a negative-inside anion gradient. It is postulated that the latter gradient is the immediate "pulling" force for the influx of Ca(2+) on the electrogenic Ca(2+) carrier in respiring mitochondria under intracellular conditions. Since mitochondria in the cell are normally exposed to an excess of phosphate (and the bicarbonate-CO(2) system), particularly in state 4, inward transport of these proton-yielding anions probably precedes and is necessary for inward transport of Ca(2+) and other cations under biological conditions. These observations indicate that a negative-inside gradient of phosphate generated by electron transport is a common step and provides the immediate motive power not only for (a) the inward transport of dicarboxylates and tricarboxylates and (b) the energy-dependent exchange of external ADP(3-) for internal ATP(4-) during oxidative phosphorylation, as has already been established, but also for (c) the inward transport of Ca(2+), K(+), and other cations.

  15. Preliminary integrated calculation of radionuclide cation and anion transport at Yucca Mountain using a geochemical model

    International Nuclear Information System (INIS)

    Birdsell, K.H.; Campbell, K.; Eggert, K.G.; Travis, B.J.

    1989-01-01

    This paper presents preliminary transport calculations for radionuclide movement at Yucca Mountain using preliminary data for mineral distributions, retardation parameter distributions, and hypothetical recharge scenarios. These calculations are not performance assessments, but are used to study the effectiveness of the geochemical barriers at the site at mechanistic level. The preliminary calculations presented have many shortcomings and should be viewed only as a demonstration of the modeling methodology. The simulations were run with TRACRN, a finite-difference porous flow and radionuclide transport code developed for the Yucca Mountain Project. Approximately 30,000 finite-difference nodes are used to represent the unsaturated and saturated zones underlying the repository in three dimensions. Sorption ratios for the radionuclides modeled are assumed to be functions of mineralogic assemblages of the underlying rock. These transport calculations present a representative radionuclide cation, 135 Cs and anion, 99 Tc. The effects on transport of many of the processes thought to be active at Yucca Mountain may be examined using this approach. The model provides a method for examining the integration of flow scenarios, transport, and retardation processes as currently understood for the site. It will also form the basis for estimates of the sensitivity of transport calculations to retardation processes. 11 refs., 17 figs., 1 tab

  16. Renal Organic Anion Transporters (SLC22 Family): Expression, Regulation, Roles in Toxicity, and Impact on Injury and Disease

    OpenAIRE

    Wang, Li; Sweet, Douglas H.

    2012-01-01

    Organic solute flux across the basolateral and apical membranes of renal proximal tubule cells is a key process for maintaining systemic homeostasis. It represents an important route for the elimination of metabolic waste products and xenobiotics, as well as for the reclamation of essential compounds. Members of the organic anion transporter (OAT, SLC22) family expressed in proximal tubules comprise one pathway mediating the active renal secretion and reabsorption of organic anions. Many drug...

  17. Transport of organic anions through the erythrocyte membrane as K+-valinomycin complexes.

    Science.gov (United States)

    Marinetti, G V; Skarin, A; Whitman, P

    1978-04-26

    K+, Rb+, or Cs+ complexes of valinomycin form ion pair complexes with picric acid and trinitrobenzenesulfonate (TNBS). The formation of a picrate-K+-valinomycin complex is supported by spectral evidence. These complexes have zero net charge and readily permeate the intact erythrocyte membrane. The K+-valinomycin complex has been used to convert the nonpenetrating TNBS into a penetrating covalent probe, making it as useful vectorial probe to measure accessible amino groups of proteins and phospholipids on both sites of the erythrocyte membrane. The enhanced transport of TNBS into the cell by valinomycin is dependent on external K+ in the medium. The entry of TNBS into the cell is manifested by an increased labeling of hemoglobin and membrane phosphatidylethanolamine (PE). Stilbeneisothiocyanatedisulfonate (SITS) and anilinonaphthalenesulfonate (ANS) inhibit both the basal and K+-valinomycin stimulated labeling of PE and hemoglobin by TNBS. The data suggest two independent effects of ANS and SITS, one mediated by an inhibition of the anion transport protein and another by the incorporation of these hydrobic anions into the cell membrane with an increase in negative charge on the membrane which leads to an inhibition of TNBS permeation into the cell by electrostatic repulsion.

  18. Structural transition, subgap states, and carrier transport in anion-engineered zinc oxynitride nanocrystalline films

    International Nuclear Information System (INIS)

    Xian, Fenglin; Ye, Jiandong; Gu, Shulin; Tan, Hark Hoe; Jagadish, Chennupati

    2016-01-01

    In this work, anion alloying is engineered in ZnON nanocrystalline films, and the resultant evolution of the structural transition, subgap states, and carrier transport is investigated. A broad distribution of sub-gap states above the valence band maximum is introduced by nitrogen due to the hybridization of N 2p and O 2p orbitals. The phase transition from partially amorphous states to full crystallinity occurs above a characteristic growth temperature of 100 °C, and the localized states are suppressed greatly due to the reduction of nitrogen composition. The electronic properties are dominated by grain boundary scattering and electron transport across boundary barriers through thermal activation at band edge states at high temperatures. The conductivity below 130 K exhibits a weak temperature dependence, which is a signature of variable-range hopping conduction between localized states introduced by nitrogen incorporation.

  19. Structural transition, subgap states, and carrier transport in anion-engineered zinc oxynitride nanocrystalline films

    Energy Technology Data Exchange (ETDEWEB)

    Xian, Fenglin [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia); Ye, Jiandong, E-mail: yejd@nju.edu.cn [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia); School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Gu, Shulin [School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Tan, Hark Hoe; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia)

    2016-07-11

    In this work, anion alloying is engineered in ZnON nanocrystalline films, and the resultant evolution of the structural transition, subgap states, and carrier transport is investigated. A broad distribution of sub-gap states above the valence band maximum is introduced by nitrogen due to the hybridization of N 2p and O 2p orbitals. The phase transition from partially amorphous states to full crystallinity occurs above a characteristic growth temperature of 100 °C, and the localized states are suppressed greatly due to the reduction of nitrogen composition. The electronic properties are dominated by grain boundary scattering and electron transport across boundary barriers through thermal activation at band edge states at high temperatures. The conductivity below 130 K exhibits a weak temperature dependence, which is a signature of variable-range hopping conduction between localized states introduced by nitrogen incorporation.

  20. Glial and Neuronal Glutamate Transporters Differ in the Na+ Requirements for Activation of the Substrate-Independent Anion Conductance

    Directory of Open Access Journals (Sweden)

    Christopher B. Divito

    2017-05-01

    Full Text Available Excitatory amino acid transporters (EAATs are secondary active transporters of L-glutamate and L- or D-aspartate. These carriers also mediate a thermodynamically uncoupled anion conductance that is gated by Na+ and substrate binding. The activation of the anion channel by binding of Na+ alone, however, has only been demonstrated for mammalian EAAC1 (EAAT3 and EAAT4. To date, no difference has been observed for the substrate dependence of anion channel gating between the glial, EAAT1 and EAAT2, and the neuronal isoforms EAAT3, EAAT4 and EAAT5. Here we describe a difference in the Na+-dependence of anion channel gating between glial and neuronal isoforms. Chloride flux through transporters without glutamate binding has previously been described as substrate-independent or “leak” channel activity. Choline or N-methyl-D-glucamine replacement of external Na+ ions significantly reduced or abolished substrate-independent EAAT channel activity in EAAT3 and EAAT4 yet has no effect on EAAT1 or EAAT2. The interaction of Na+ with the neuronal carrier isoforms was concentration dependent, consistent with previous data. The presence of substrate and Na+-independent open states in the glial EAAT isoforms is a novel finding in the field of EAAT function. Our results reveal an important divergence in anion channel function between glial and neuronal glutamate transporters and highlight new potential roles for the EAAT-associated anion channel activity based on transporter expression and localization in the central nervous system.

  1. The importance of OH − transport through anion exchange membrane in microbial electrolysis cells

    KAUST Repository

    Ye, Yaoli

    2018-01-11

    In two-chamber microbial electrolysis cells (MECs) with anion exchange membranes (AEMs), a phosphate buffer solution (PBS) is typically used to avoid increases in catholyte pH as Nernst equation calculations indicate that high pHs adversely impact electrochemical performance. However, ion transport between the chambers will also impact performance, which is a factor not included in those calculations. To separate the impacts of pH and ion transport on MEC performance, a high molecular weight polymer buffer (PoB), which was retained in the catholyte due to its low AEM transport and cationic charge, was compared to PBS in MECs and abiotic electrochemical half cells (EHCs). In MECs, catholyte pH control was less important than ion transport. MEC tests using the PoB catholyte, which had a higher buffer capacity and thus maintained a lower catholye pH (<8), resulted in a 50% lower hydrogen production rate (HPR) than that obtained using PBS (HPR = 0.7 m3-H2 m−3 d−1) where the catholyte rapidly increased to pH = 12. The main reason for the decreased performance using PoB was a lack of hydroxide ion transfer into the anolyte to balance pH. The anolyte pH in MECs rapidly decreased to 5.8 due to a lack of hydroxide ion transport, which inhibited current generation by the anode, whereas the pH was maintained at 6.8 using PBS. In abiotic tests in ECHs, where the cathode potential was set at −1.2 V, the HPR was 133% higher using PoB than PBS due to catholyte pH control, as the anolyte pH was not a factor in the performance. These results show that maintaining charge transfer to control anolyte pH is more important than obtaining a more neutral pH catholyte.

  2. Endogenous metabolites that are substrates of organic anion transporter's (OATs) predict methotrexate clearance.

    Science.gov (United States)

    Muhrez, Kienana; Benz-de Bretagne, Isabelle; Nadal-Desbarats, Lydie; Blasco, Hélène; Gyan, Emmanuel; Choquet, Sylvain; Montigny, Frédéric; Emond, Patrick; Barin-Le Guellec, Chantal

    2017-04-01

    Variable pharmacokinetics of high-dose-methotrexate (MTX) is responsible for severe toxicities. Unpredictable overexposure still occurs during some courses despite having controlled the main factors known to play a role in its elimination. The aim of our study was to evaluate whether the urine metabolomic profile measured at the time of MTX administration is predictive of the drug's clearance and/or of treatment-related toxicity. We analyzed the urine content of endogenous metabolites before MTX administration in a cohort of adult patients treated for lymphoid malignancies. Individual MTX clearance (MTX CL ) was estimated from population pharmacokinetic analyses of therapeutic drug monitoring data. We determined the urine metabolite content by gas chromatography-mass spectrometry (GC-MS) and applied Partial Least Square (PLS) analysis to assess the relationship between the urine metabolome and MTX CL . External validation was applied to evaluate the performances of the PLS model. We used orthogonal partial least squares discriminant analysis (OPLS-DA) to distinguish patients with normal or delayed elimination, and patients with or without toxicity. Sixty-two patients were studied. We obtained a very good prediction of individual MTX clearance using a set of 28 metabolites present in patient urine at baseline. The mean prediction error and precision were -0.36% and 21.4%, respectively, for patients not included in the model. The model included a set of endogenous organic anions, of which the tubular secretion depends on organic anion transporter (OAT) function. Our analyses did not allow us to discriminate between patients with or without delayed elimination or those who did or did not experience toxicity. Urinary metabolomics can be informative about an individual's ability to clear MTX. More broadly, it paves the way for the development of a biomarker of tubular secretion, easily measurable from endogenous substances. Copyright © 2016 Elsevier Ltd. All rights

  3. Organic anion and cation transport in vitro by dog choroid plexus: Effects of neuroleptics and tricyclic antidepressants

    International Nuclear Information System (INIS)

    Barany, E.H.

    1979-01-01

    Dog lateral choroid plexus accumulates the cation 14 C-emepronium and the divalent anion 125 I-iodipamide in vitro. At 10 μM, high potency neuroleptics with a substituted piperazine side chain and also haloperidol depress only the uptake of the cation and even stimulate the uptake of the anion. In contrast, at 1-10μM, the accumulation of both test substances is inhibited by neuroleptics and tricyclic antidepresssants with an aliphatic side chain. Such unspecific effects on seemingly unrelated transport systems at concentrations reached clinically in the CSF might explain some side actions of low potency neuroleptics and antidepressants. (author)

  4. Interaction between rhein acyl glucuronide and methotrexate based on human organic anion transporters.

    Science.gov (United States)

    Yuan, Yuan; Yang, Hua; Kong, Linghua; Li, Yuan; Li, Ping; Zhang, Hongjian; Ruan, Jianqing

    2017-11-01

    Rhein, a major bioactive compound of many medicinal herbs and the prodrug of diacerein, is often used with low dose of methotrexate as drug combination to treat rheumatoid arthritis. In this study, potential drug-drug interaction between methotrexate and rhein was investigated based on organic anion transporters (OAT). Our study demonstrated that rhein acyl glucuronide (RAG), the major metabolite of rhein in the human blood circulation, significantly inhibited the uptake of p-aminohippurate in hOAT1 transfected cells with IC 50 value of 691 nM and estrone sulfate uptake in hOAT3 transfected cells with IC 50 value of 78.5 nM. As the substrate of both hOAT1 and hOAT3, the methotrexate transport was significantly inhibited by RAG in hOAT1 transfected cells at 50 μM and hOAT3 transfected cells at 1 μM by 69% and 87%, respectively. Further in vivo study showed that after co-administrated with RAG in rats the AUC 0-24 values of methotrexate increased from 3109 to 5370 ng/mL*hr and the t 1/2 was prolonged by 40.5% (from 7.4 to 10.4 h), demonstrating the inhibitory effect of RAG on methotrexate excretion. In conclusion, rhein acyl glucuronide could significantly decrease the transport of methotrexate by both hOAT1 and hOAT3. The combination use of rhein, diacerein or other rhein-containing herbs with methotrexate may cause obvious drug-drug interaction and require close monitoring for potential drug interaction in clinical practice. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Bidirectional transport of iminodiacetic organic anion analogues between plasma and hepatocyte

    Energy Technology Data Exchange (ETDEWEB)

    Peters, A.M.; Myers, M.J.; Mohammadtaghi, S.; Mubashar, M. [Department of Imaging, Division of Investigative Sciences, Imperial College School of Medicine, London (United Kingdom); Mathie, R.T. [Department of Gastrointestinal Surgery, Division of Surgery, Anaesthetics and Intensive Care, Imperial College School of Medicine, London (United Kingdom)

    1998-07-01

    The kinetics of organic anions are well described and back-diffusion from hepatocyte to plasma is accepted. Although iminodiacetic (IDA) analogues, as organic anions, should also show bidirectional transport between hepatocyte and plasma, this has not been directly demonstrated heretofore. The aim of this study was to directly demonstrate back-diffusion and to quantify it in terms of its fractional rate constant. Kinetics of diethyl IDA were studied in three anaesthetised dogs in which femoral arterial and hepatic venous samples were obtained after injection of tracer into (a) a peripheral vein or (b) hepatic artery or portal vein. Arterial time-concentration curves were also compared between peripheral venous and either hepatic arterial or portal venous injections. Time-activity curves were recorded from regions of interest over the cardiac blood pool and peripheral hepatic parenchyma in 30 patients undergoing routine IDA hepatobiliary imaging with diethyl IDA or mebrofenin and fractional rate constants of clearance of IDA from the hepatocyte compared between compartmental and deconvolution analyses. After peripheral injection in dogs, there was an early arteriovenous concentration gradient across the liver indicating an hepatocyte extraction fraction in the three animals of 0.9, 0.8 and 0.6. The net extraction fraction decreased exponentially over 40 min. Time-concentration curves from hepatic vein and femoral artery were virtually superimposed following intrahepatic injections. Peripheral arterial curves, however, had different shapes according to whether injections were intrahepatic or peripheral, and were consistent with significant back-diffusion. In clinical studies, the blood disappearance curves were fitted as the sum of two exponentials and the liver curves as the difference of two exponentials (with rate constants denoted {alpha}{sub 1}{sup h} and {alpha}{sub 2}{sup h}). Based on compartmental analysis of the blood curves, the sum of the fractional rate

  6. Does lipophilicity affect the effectiveness of a transmembrane anion transporter? Insight from squaramido-functionalized bis(choloyl) conjugates.

    Science.gov (United States)

    Li, Zhi; Deng, Li-Qun; Chen, Jin-Xiang; Zhou, Chun-Qiong; Chen, Wen-Hua

    2015-12-28

    Six squaramido-functionalized bis(choloyl) conjugates were synthesized and fully characterized on the basis of NMR ((1)H and (13)C) and ESI MS (LR and HR) data. Their transmembrane anionophoric activity was investigated in detail by means of chloride ion selective electrode technique and pyranine assay. The data indicate that this set of compounds is capable of promoting the transmembrane transport of anions presumably via proton/anion symport and anion exchange processes, and that lipophilicity in terms of clog P from 3.90 to 8.32 affects the apparent ion transport rate in a concentration-dependent fashion. Detailed kinetic analysis on the data obtained from both the chloride efflux and pH discharge experiments reveals that there may exist an optimum clog P range for the intrinsic ion transport rate. However, lipophilicity exhibits little effect on the effectiveness of this set of compounds in terms of either k2/Kdiss or EC50 values.

  7. The organic anion transporter OAT3 enhances the glucosuric effect of the SGLT2 inhibitor empagliflozin.

    Science.gov (United States)

    Fu, Yiling; Breljak, Davorka; Onishi, Akira; Batz, Falk; Patel, Rohit; Huang, Winnie; Song, Panai; Freeman, Brent; Mayoux, Eric; Koepsell, Hermann; Anzai, Naohiko; Nigam, Sanjay K; Sabolić, Ivan; Vallon, Volker

    2018-02-07

    The SGLT2 inhibitor empagliflozin (plasma protein binding ~88%) may reach its target in the brush border of the early proximal tubule by glomerular filtration and tubular secretion. Here we determined whether empagliflozin is secreted by renal tubules, and whether genetic knockout of the basolateral organic anion transporter Oat3 (-/-) affects its tubular secretion or glucosuric effect. Renal clearance studies in wild-type (WT) mice showed that tubular secretion accounted for 50-70% of empagliflozin urinary excretion. Immunostaining indicated that SGLT2 and OAT3 localization partially overlapped in proximal tubule S1 and S2 segments. Glucosuria in metabolic cage studies was reduced in Oat3-/- vs. WT mice for acute empagliflozin doses of 1, 3, and 10mg/kg, whereas 30mg/kg induced similar maximal glucosuria in both genotypes. Chronic application of empagliflozin (~25mg kg-1 day-1) in Oat3-/- mice was associated with lower urinary glucose to creatinine ratios despite maintaining slightly higher blood glucose levels than WT. On a whole kidney level, renal secretion of empagliflozin was largely unchanged in Oat3-/- mice. However, the absence of OAT3 attenuated the influence of empagliflozin on fractional glucose excretion; higher levels of plasma or filtered empagliflozin were needed to induce similar increases in fractional renal glucose excretion. We conclude that empagliflozin is excreted into the urine to similar extent by glomerular filtration and tubular secretion. The latter can occur largely independent of OAT3. However, OAT3 increases the glucosuric effect of empagliflozin, which may relate to the partial overlap of its localization with SGLT2 and OAT3-mediated tubular secretion of empagliflozin in the early proximal tubule.

  8. Molecular evidence for an involvement of organic anion transporters (OATs) in aristolochic acid nephropathy

    International Nuclear Information System (INIS)

    Bakhiya, Nadiya; Arlt, Volker M.; Bahn, Andrew; Burckhardt, Gerhard; Phillips, David H.; Glatt, Hansruedi

    2009-01-01

    Aristolochic acid (AA), present in Aristolochia species, is the major causative agent in the development of severe renal failure and urothelial cancers in patients with AA nephropathy. It may also be a cause of Balkan endemic nephropathy. Epithelial cells of the proximal tubule are the primary cellular target of AA. To study whether organic anion transporters (OATs) expressed in proximal tubule cells are involved in uptake of AA, we used human epithelial kidney (HEK293) cells stably expressing human (h) OAT1, OAT3 or OAT4. AA potently inhibited the uptake of characteristic substrates, p-aminohippurate for hOAT1 and estrone sulfate for hOAT3 and hOAT4. Aristolochic acid I (AAI), the more cytotoxic and genotoxic AA congener, exhibited high affinity for hOAT1 (K i = 0.6 μM) as well as hOAT3 (K i = 0.5 μM), and lower affinity for hOAT4 (K i = 20.6 μM). Subsequently, AAI-DNA adduct formation (investigated by 32 P-postlabelling) was used as a measure of AAI uptake. Significantly higher levels of adducts occurred in hOAT-expressing cells than in control cells: this effect was abolished in the presence of the OAT inhibitor probenecid. In Xenopus laevis oocytes hOAT-mediated efflux of p-aminohippurate was trans-stimulated by extracellular AA, providing further molecular evidence for AA translocation by hOATs. Our study indicates that OATs can mediate the uptake of AA into proximal tubule cells and thereby participate in kidney cell damage by this toxin.

  9. Intestinal transporters for endogenic and pharmaceutical organic anions: The challenges of deriving in-vitro kinetic parameters for the prediction of clinically relevant drug-drug interactions

    DEFF Research Database (Denmark)

    Grandvuinet, Anne Sophie; Vestergaard, Henrik Tang; Rapin, Nicolas

    2012-01-01

    of the apical sodium-dependent bile acid transporter (ASBT), the breast cancer resistance protein (BCRP), the monocarboxylate transporters (MCT) 1, MCT3-5, the multidrug resistance associated proteins (MRP) 1-6, the organic anion transporting polypetides (OATP) 2B1, 1A2, 3A1 and 4A1, and the organic solute...

  10. Renal organic anion transporters (SLC22 family): expression, regulation, roles in toxicity, and impact on injury and disease.

    Science.gov (United States)

    Wang, Li; Sweet, Douglas H

    2013-01-01

    Organic solute flux across the basolateral and apical membranes of renal proximal tubule cells is a key process for maintaining systemic homeostasis. It represents an important route for the elimination of metabolic waste products and xenobiotics, as well as for the reclamation of essential compounds. Members of the organic anion transporter (OAT, SLC22) family expressed in proximal tubules comprise one pathway mediating the active renal secretion and reabsorption of organic anions. Many drugs, pesticides, hormones, heavy metal conjugates, components of phytomedicines, and toxins are OAT substrates. Thus, through transporter activity, the kidney can be a target organ for their beneficial or detrimental effects. Detailed knowledge of the OATs expressed in the kidney, their membrane targeting, substrate specificity, and mechanisms of action is essential to understanding organ function and dysfunction. The intracellular processes controlling OAT expression and function, and that can thus modulate kidney transport capacity, are also critical to this understanding. Such knowledge is also providing insight to new areas such as renal transplant research. This review will provide an overview of the OATs for which transport activity has been demonstrated and expression/function in the kidney observed. Examples establishing a role for renal OATs in drug clearance, food/drug-drug interactions, and renal injury and pathology are presented. An update of the current information regarding the regulation of OAT expression is also provided.

  11. Ion transport resistance in Microbial Electrolysis Cells with anion and cation exchange membranes

    NARCIS (Netherlands)

    Sleutels, T.H.J.A.; Hamelers, H.V.M.; Rozendal, R.A.; Buisman, C.J.N.

    2009-01-01

    Previous studies have shown that Microbial Electrolysis Cells (MECs) perform better when an anion exchange membrane (AEM) than when a cation exchange membrane (CEM) separates the electrode chambers. Here, we have further studied this phenomenon by comparing two analysis methods for

  12. Self-Assembly of Fluorinated Sugar Amino Acid Derived α,γ-Cyclic Peptides into Transmembrane Anion Transport.

    Science.gov (United States)

    Burade, Sachin S; Saha, Tanmoy; Bhuma, Naresh; Kumbhar, Navanath; Kotmale, Amol; Rajamohanan, Pattuparambil R; Gonnade, Rajesh G; Talukdar, Pinaki; Dhavale, Dilip D

    2017-11-03

    Syntheses of fluorinated sugar amino acid derived α,γ-cyclic tetra- and hexapeptides are reported. The IR, NMR, ESI-MS, CD, and molecular modeling studies of cyclic tetra- and hexapeptides showed C 2 and C 3 symmetric flat oval- and triangular-ring shaped β-strand conformations, respectively, which appear to self-assemble into nanotubes. The α,γ-cyclic hexapeptide (EC 50 = 2.14 μM) is found to be a more efficient ion transporter than α,γ-cyclic tetrapeptide (EC 50 = 14.75 μM). The anion selectivity and recognition of α,γ-cyclic hexapeptide with NO 3 - ion is investigated.

  13. Drug trafficking in mice: In vivo functions of OATP uptake and ABC efflux transporters

    NARCIS (Netherlands)

    Iusuf, D.

    2013-01-01

    In recent years, there has been increasing attention for drug uptake transporters of the Organic Anion-Transporting Polypeptide (human OATP, mouse Oatp, gene names SLCO, Slco) superfamily. Especially the OATP1A and OATP1B subfamilies turn out to have important physiological and pharmacological

  14. Functional, structural and phylogenetic analysis of domains underlying the Al-sensitivity of the aluminium-activated malate/anion transporter, TaALMT1

    Science.gov (United States)

    TaALMT1 (Triticum aestivum Aluminum Activated Malate Transporter) is the founding member of a novel gene family of anion transporters (ALMTs) that mediate the efflux of organic acids. A small subgroup of root-localized ALMTs, including TaALMT1, is physiologically associated with in planta aluminum (...

  15. Carbon dioxide transport in molten calcium carbonate occurs through an oxo-Grotthuss mechanism via a pyrocarbonate anion.

    Science.gov (United States)

    Corradini, Dario; Coudert, François-Xavier; Vuilleumier, Rodolphe

    2016-05-01

    The reactivity, speciation and solvation structure of CO2 in carbonate melts are relevant for both the fate of carbon in deep geological formations and for its electroreduction to CO (to be used as fuel) when solvated in a molten carbonate electrolyte. In particular, the high solubility of CO2 in carbonate melts has been tentatively attributed to the formation of the pyrocarbonate anion, C2O5(2-). Here we study, by first-principles molecular dynamics simulations, the behaviour of CO2 in molten calcium carbonate. We find that pyrocarbonate forms spontaneously and the identity of the CO2 molecule is quickly lost through O(2-) exchange. The transport of CO2 in this molten carbonate thus occurs in a fashion similar to the Grotthuss mechanism in water, and is three times faster than molecular diffusion. This shows that Grotthuss-like transport is more general than previously thought.

  16. Up-regulation of the multidrug resistance genes, mrp1 and mdr1b, and down-regulation of the organic anion transporter, Mrp2, and the bile salt transporter, spgp, in endotoxemic rat liver

    NARCIS (Netherlands)

    Vos, TA; Hooiveld, GJEJ; Childs, S; Meijer, DKF; Moshage, H; Jansen, PLM; Muller, M

    1998-01-01

    Endotoxin-induced cholestasis is mainly caused by an impaired canalicular secretion. Mrp2, the canalicular multispecific organic anion transporter, is strongly downregulated in this situation, and canalicular bile salt secretion is also reduced. We hypothesized that other adenosine

  17. Organic anion transporter 2 transcript variant 1 shows broad ligand selectivity when expressed in multiple cell lines.

    Science.gov (United States)

    Hotchkiss, Adam G; Berrigan, Liam; Pelis, Ryan M

    2015-01-01

    Organic anion transporter 2 (OAT2) is likely important for renal and hepatic drug elimination. Three variants of the OAT2 peptide sequence have been described - OAT2 transcript variant 1 (OAT2-tv1), OAT2 transcript variant 2 (OAT2-tv2), and OAT2 transcript variant 3 (OAT2-tv3). Early studies helping to define the ligand selectivity of OAT2 failed to identify the variant used, and the studies used several heterologous expression systems. In preliminary studies using OAT2-tv1, we failed to observe transport of several previously identified substrates, leading us to speculate that ligand selectivity of OAT2 differs with variant and/or heterologous expression system. The purpose was to further investigate the ligand selectivity of the OAT2 variants expressed in multiple cell types. We cloned OAT2-tv1 and OAT2-tv2, but were unsuccessful at amplifying mRNA for OAT2-tv3 from human kidney. OAT2-tv1 and OAT2-tv2 were individually expressed in human embryonic kidney (HEK), Madin-Darby canine kidney (MDCK), or Chinese hamster ovary (CHO) cells. mRNA for OAT2-tv1 and OAT2-tv2 was demonstrated in each cell type transfected with the respective construct, indicating their expression. OAT2-tv1 trafficked to the plasma membrane of all three cell types, but OAT2-tv2 did not. OAT2-tv1 transported penciclovir in all three cell types, but failed to transport para-aminohippurate, succinate, glutarate, estrone-3-sulfate, paclitaxel or dehydroepiandrosterone sulfate - previously identified substrates of OAT2-tv2. Not surprising given its lack of plasma membrane expression, OAT2-tv2 failed to transport any of the organic solutes examined, including penciclovir. Penciclovir transport by OAT2-tv1 was sensitive to large (e.g., cyclosporine A) and small (e.g., allopurinol) organic compounds, as well as organic anions, cations and neutral compounds, highlighting the multiselectivity of OAT2-tv1. The potencies with which indomethacin, furosemide, cyclosporine A and cimetidine inhibited OAT2-tv1

  18. Probenecid, an inhibitor of transmembrane organic anion transporters, alters tissue distribution of DNA adducts in 1-hydroxymethylpyrene-treated rats.

    Science.gov (United States)

    Monien, Bernhard H; Müller, Carolin; Bakhiya, Nadiya; Donath, Claudia; Frank, Heinz; Seidel, Albrecht; Glatt, Hansruedi

    2009-07-28

    1-Methylpyrene (1-MP), an abundant alkylated polycyclic aromatic hydrocarbon, is activated by side-chain hydroxylation to 1-hydroxymethylpyrene (1-HMP) and subsequent sulfo-conjugation to electrophilic 1-sulfooxymethylpyrene (1-SMP). In rats, this activation mainly occurs in liver. 1-SMP may react with hepatic DNA or be exported into the blood circulation to reach other tissues, in particular kidneys. Findings with recombinant cell lines suggest that renal 1-SMP uptake proceeds via organic anion transporters (OATs). Here, we tested the hypothesis that probenecid, a characteristic OAT inhibitor, interferes with kidney damage brought about by 1-SMP formed in rats. 1-HMP was administered intraperitoneally to 30 rats, half of which were co-treated with probenecid. The tissue distribution of DNA adducts was analyzed using (32)P-postlabeling and isotope dilution LC-MS/MS for the detection of the adducts N(2)-(1-methylpyrenyl)-2'-deoxyguanosine and N(6)-(1-methylpyrenyl)-2'-deoxyadenosine. In rats treated solely with 1-HMP, adduct levels in kidney tissue were about 3-fold and 8-fold higher than those in liver and lung, respectively. After co-treatment with probenecid, hepatic and pulmonary adduct levels were 12-fold and 4-fold elevated, respectively, whereas renal adduct levels were slightly lower compared to those of rats receiving 1-HMP alone. Moreover, serum levels of 1-SMP were increased 23-fold in animals pre-treated with probenecid. The differential effects on hepatic and pulmonary adduct levels suggest that not only renal OATs, but also additional anion transporters, e.g. those mediating the hepatic export of 1-SMP into the bile, were inhibited. Thus, transmembrane transport proteins play a crucial role in the distribution of reactive phase II metabolites, and thereby in tissue allocation of DNA adducts.

  19. Probenecid, an organic anion transporter 1 and 3 inhibitor, increases plasma and brain exposure of N-acetylcysteine.

    Science.gov (United States)

    Hagos, Fanuel T; Daood, Monica J; Ocque, Jacob A; Nolin, Thomas D; Bayir, Hulya; Poloyac, Samuel M; Kochanek, Patrick M; Clark, Robert S B; Empey, Philip E

    2017-04-01

    1. N-acetylcysteine (NAC) is being investigated as an antioxidant for several conditions including traumatic brain injury, but the mechanism by which it crosses membrane barriers is unknown. We have attempted to understand how the transporter inhibitor, probenecid, affects NAC pharmacokinetics and to evaluate the interaction of NAC with transporters. 2. Juvenile Sprague-Dawley rats were administered NAC alone or in combination with probenecid intraperitoneally. Plasma and brain samples were collected serially and NAC concentrations were measured. Transporter studies were conducted with human embryonic kidney-293 cells that overexpress organic anion transporter (OAT)1 or OAT3 and with human multi-drug resistance-associated protein (MRP)1 or MRP4 membrane vesicles. 3. NAC area under the curve was increased in plasma (1.65-fold) and brain (2.41-fold) by probenecid. The apparent plasma clearance was decreased by 65%. Time- and concentration-dependent NAC uptake that was inhibitable by probenecid was observed with OAT1 and OAT3. No uptake of NAC was observed with MRP1 or MRP4. 4. Our results indicate for the first time that NAC is substrate for OAT1 and OAT3 and that probenecid increases NAC plasma and brain exposure in vivo. These data provide insight regarding how NAC crosses biological barriers and suggest a promising therapeutic strategy to increase NAC exposure.

  20. Na+-taurocholate cotransporting polypeptide (NTCP/SLC10A1) ortholog in the marine skateLeucoraja erinaceais not a physiological bile salt transporter.

    Science.gov (United States)

    Yu, Dongke; Zhang, Han; Lionarons, Daniel A; Boyer, James L; Cai, Shi-Ying

    2017-04-01

    The Na + -dependent taurocholate cotransporting polypeptide (NTCP/SLC10A1) is a hepatocyte-specific solute carrier, which plays an important role in maintaining bile salt homeostasis in mammals. The absence of a hepatic Na + -dependent bile salt transport system in marine skate and rainbow trout raises a question regarding the function of the Slc10a1 gene in these species. Here, we have characterized the Slc10a1 gene in the marine skate, Leucoraja erinacea The transcript of skate Slc10a1 (skSlc10a1) encodes 319 amino acids and shares 46% identity to human NTCP (hNTCP) with similar topology to mammalian NTCP. SkSlc10a1 mRNA was mostly confined to the brain and testes with minimal expression in the liver. An FXR-bile salt reporter assay indicated that skSlc10a1 transported taurocholic acid (TCA) and scymnol sulfate, but not as effectively as hNTCP. An [ 3 H]TCA uptake assay revealed that skSlc10a1 functioned as a Na + -dependent transporter, but with low affinity for TCA ( K m = 92.4 µM) and scymnol sulfate ( K i = 31 µM), compared with hNTCP (TCA, K m = 5.4 µM; Scymnol sulfate, K i = 3.5 µM). In contrast, the bile salt concentration in skate plasma was 2 µM, similar to levels seen in mammals. Interestingly, skSlc10a1 demonstrated transport activity for the neurosteroids dehydroepiandrosterone sulfate and estrone-3-sulfate at physiological concentration, similar to hNTCP. Together, our findings indicate that skSlc10a1 is not a physiological bile salt transporter, providing a molecular explanation for the absence of a hepatic Na + -dependent bile salt uptake system in skate. We speculate that Slc10a1 is a neurosteroid transporter in skate that gained its substrate specificity for bile salts later in vertebrate evolution. Copyright © 2017 the American Physiological Society.

  1. In silico analysis and experimental validation of azelastine hydrochloride (N4) targeting sodium taurocholate co-transporting polypeptide (NTCP) in HBV therapy.

    Science.gov (United States)

    Fu, L-L; Liu, J; Chen, Y; Wang, F-T; Wen, X; Liu, H-Q; Wang, M-Y; Ouyang, L; Huang, J; Bao, J-K; Wei, Y-Q

    2014-08-01

    The aim of this study was to explore sodium taurocholate co-transporting polypeptide (NTCP) exerting its function with hepatitis B virus (HBV) and its targeted candidate compounds, in HBV therapy. Identification of NTCP as a novel HBV target for screening candidate small molecules, was used by phylogenetic analysis, network construction, molecular modelling, molecular docking and molecular dynamics (MD) simulation. In vitro virological examination, q-PCR, western blotting and cytotoxicity studies were used for validating efficacy of the candidate compound. We used the phylogenetic analysis of NTCP and constructed its protein-protein network. Also, we screened compounds from Drugbank and ZINC, among which five were validated for their authentication in HepG 2.2.15 cells. Then, we selected compound N4 (azelastine hydrochloride) as the most potent of them. This showed good inhibitory activity against HBsAg (IC50 = 7.5 μm) and HBeAg (IC50 = 3.7 μm), as well as high SI value (SI = 4.68). Further MD simulation results supported good interaction between compound N4 and NTCP. In silico analysis and experimental validation together demonstrated that compound N4 can target NTCP in HepG2.2.15 cells, which may shed light on exploring it as a potential anti-HBV drug. © 2014 John Wiley & Sons Ltd.

  2. Structure-affinity relationship in the interactions of human organic anion transporter 1 with caffeine, theophylline, theobromine and their metabolites.

    Science.gov (United States)

    Sugawara, Mitsuru; Mochizuki, Takahiro; Takekuma, Yoh; Miyazaki, Katsumi

    2005-08-15

    It is well known that human organic anion transporter 1 (hOAT1) transports many kinds of drugs, endogenous compounds, and toxins. However, little is known about the structure-affinity relationship. The aim of this study was to elucidate the structure-affinity relationship using a series of structurally related compounds that interact with hOAT1. Inhibitory effects of xanthine- and uric acid-related compounds on the transport of p-aminohippuric acid were examined using CHO-K1 cells stably expressing hOAT1. The order of potency for the inhibitory effects of xanthine-related compounds on PAH uptake was 1-methyl derivative>7-methyl derivative>3-methyl derivative falling dotsxanthine>1,3,7-trimethyl derivative (caffeine). The order of potency of the inhibition was 1,3,7-trimethyluric acid>1,3-dimethyluric acid>1,7-dimethyluric acid>1-methyluric acid>uric acid. A significant correlation between inhibitory potency and lipophilicity of the tested uric acid-related compounds was observed. The main determinant of the affinity of xanthine-related compounds is the position of the methyl group. On the other hand, lipophilicity is the main determinant of the affinity of uric acid-related compounds.

  3. Impaired activity of bile bile canalicular organic anion transporter (Mrp2/cmoat) is not the main cause of ethinylestradiol-induced cholestasis in the rat

    NARCIS (Netherlands)

    Koopen, NR; Wolters, H; Havinga, R; Vonk, RJ; Jansen, PLM; Muller, M; Kuipers, F

    To test the hypothesis that impaired activity of the bile canalicular organic anion transporting system mrp2 (cmoat) is a key event in the etiology of 17 alpha-ethinylestradiol (EE)-induced intrahepatic cholestasis in rats, EE (5 mg/kg subcutaneously daily) was administered to male normal Wistar

  4. Carbon dioxide transport in alligator blood and its erythrocyte permeability to anions and water

    DEFF Research Database (Denmark)

    Jensen, F B; Wang, T; Jones, D R

    1998-01-01

    + binding. Erythrocyte volume, plasma pH, and plasma HCO3- concentration also varied little with the degree of oxygenation. Diffusional water permeability was higher in oxygenated than deoxygenated RBCs. The RBCs have rapid band 3-mediated Cl- and HCO3- transport, which was not affected by degree...

  5. Interactions between organic anions on multiple transporters in Caco-2 cells

    DEFF Research Database (Denmark)

    Grandvuinet, Anne Sophie; Steffansen, Bente

    2011-01-01

    Caco-2 cell line may be used as an overall model to predict interactions on multiple membrane transporters in the intestine. Taurocholic acid (TCA) and estrone-3-sulfate (E1S) were used as model substrates. Possible inhibitors studied were TCA, E1S, taurolithocholic acid, fluvastatin, and glipizide...

  6. Gastric inhibitory polypeptide analogues

    DEFF Research Database (Denmark)

    Holst, Jens Juul

    2002-01-01

    Gastric inhibitory polypeptide (GIP, also called glucose-dependent insulinotropic polypeptide) and glucagon-like peptide-1 (GLP-1) are peptide hormones from the gut that enhance nutrient-stimulated insulin secretion (the 'incretin' effect). Judging from experiments in mice with targeted deletions...

  7. Lansoprazole Exacerbates Pemetrexed-Mediated Hematologic Toxicity by Competitive Inhibition of Renal Basolateral Human Organic Anion Transporter 3.

    Science.gov (United States)

    Ikemura, Kenji; Hamada, Yugo; Kaya, Chinatsu; Enokiya, Tomoyuki; Muraki, Yuichi; Nakahara, Hiroki; Fujimoto, Hajime; Kobayashi, Tetsu; Iwamoto, Takuya; Okuda, Masahiro

    2016-10-01

    Pemetrexed, a multitargeted antifolate, is eliminated by tubular secretion via human organic anion transporter 3 (hOAT3). Although proton pump inhibitors (PPIs) are frequently used in cancer patients, the drug interaction between PPIs and pemetrexed remains to be clarified. In this study, we examined the drug interaction between pemetrexed and PPIs in hOAT3-expressing cultured cells, and retrospectively analyzed the impact of PPIs on the development of hematologic toxicity in 108 patients who received pemetrexed and carboplatin treatment of nonsquamous non-small cell lung cancer for the first time between January 2011 and June 2015. We established that pemetrexed was transported via hOAT3 (Km = 68.3 ± 11.1 µM). Lansoprazole, rabeprazole, pantoprazole, esomeprazole, omeprazole, and vonoprazan inhibited hOAT3-mediated uptake of pemetrexed in a concentration-dependent manner. The inhibitory effect of lansoprazole was much greater than those of other PPIs and the apparent IC50 value of lansoprazole against pemetrexed transport via hOAT3 was 0.57 ± 0.17 µM. The inhibitory type of lansoprazole was competitive. In a retrospective study, multivariate analysis revealed that coadministration of lansoprazole, but not other PPIs, with pemetrexed and carboplatin was an independent risk factor significantly contributing to the development of hematologic toxicity (odds ratio: 10.004, P = 0.005). These findings demonstrated that coadministration of lansoprazole could exacerbate the hematologic toxicity associated with pemetrexed, at least in part, by competitive inhibition of hOAT3. Our results would aid clinicians to make decisions of coadministration drugs to avoid drug interaction-induced side effects for achievement of safe and appropriate chemotherapy with pemetrexed. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  8. Active Hydrophilic Components of the Medicinal Herb Salvia miltiorrhiza (Danshen Potently Inhibit Organic Anion Transporters 1 (Slc22a6 and 3 (Slc22a8

    Directory of Open Access Journals (Sweden)

    Li Wang

    2012-01-01

    Full Text Available Many active components of herbal products are small organic anions, and organic anion transporters were previously demonstrated to be a potential site of drug-drug interactions. In this study, we assessed the inhibitory effects of six hydrophilic components of the herbal medicine Danshen, lithospermic acid, protocatechuic acid, rosmarinic acid, salvianolic acid A, salvianolic acid B, and tanshinol, on the function of the murine organic anion transporters, mOat1 and mOat3. All of Danshen components significantly inhibited mOat1- and mOat3-mediated substrate uptake (<0.001 with lithospermic acid (LSA, protocatechuic acid, rosmarinic acid (RMA, and salvianolic acid A (SAA producing virtually complete inhibition under test conditions. Kinetic analysis demonstrated that LSA, RMA, and SAA were competitive inhibitors. As such, values were estimated as 14.9±4.9 μM for LSA, 5.5±2.2 μM for RMA, and 4.9±2.2 μM for SAA on mOat1-mediated transport, and as 31.1±7.0 μM for LSA, 4.3±0.2 μM for RMA, and 21.3±7.7 μM for SAA on mOat3-mediated transport. These data suggest that herb-drug interactions may occur in vivo on the human orthologs of these transporters in situations of polypharmacy involving Danshen and clinical therapeutics known to be organic anion transporter substrates.

  9. Cumulative organic anion transporter-mediated drug-drug interaction potential of multiple components in salvia miltiorrhiza (danshen) preparations.

    Science.gov (United States)

    Wang, Li; Venitz, Jürgen; Sweet, Douglas H

    2014-12-01

    To evaluate organic anion transporter-mediated drug-drug interaction (DDI) potential for individual active components of Danshen (Salvia miltiorrhiza) vs. combinations using in vitro and in silico approaches. Inhibition profiles for single Danshen components and combinations were generated in stably-expressing human (h)OAT1 and hOAT3 cells. Plasma concentration-time profiles for compounds were estimated from in vivo human data using an i.v. two-compartment model (with first-order elimination). The cumulative DDI index was proposed as an indicator of DDI potential for combination products. This index was used to evaluate the DDI potential for Danshen injectables from 16 different manufacturers and 14 different lots from a single manufacturer. The cumulative DDI index predicted in vivo inhibition potentials, 82% (hOAT1) and 74% (hOAT3), comparable with those observed in vitro, 72 ± 7% (hOAT1) and 81 ± 10% (hOAT3), for Danshen component combinations. Using simulated unbound Cmax values, a wide range in cumulative DDI index between manufacturers, and between lots, was predicted. Many products exhibited a cumulative DDI index > 1 (50% inhibition). Danshen injectables will likely exhibit strong potential to inhibit hOAT1 and hOAT3 function in vivo. The proposed cumulative DDI index might improve prediction of DDI potential of herbal medicines or pharmaceutical preparations containing multiple components.

  10. The liver and kidney expression of sulfate anion transporter sat-1 in rats exhibits male-dominant gender differences.

    Science.gov (United States)

    Brzica, Hrvoje; Breljak, Davorka; Krick, Wolfgang; Lovrić, Mila; Burckhardt, Gerhard; Burckhardt, Birgitta C; Sabolić, Ivan

    2009-04-01

    The sulfate anion transporter (sat-1, Slc26a1) has been cloned from rat liver, functionally characterized, and localized to the sinusoidal membrane in hepatocytes and basolateral membrane (BLM) in proximal tubules (PT). Here, we confirm previously described localization of sat-1 protein in rat liver and kidneys and report on gender differences (GD) in its expression by immunochemical, transport, and excretion studies in rats. The approximately 85-kDa sat-1 protein was localized to the sinusoidal membrane in hepatocytes and BLM in renal cortical PT, with the male-dominant expression. However, the real-time reverse-transcription polymerase chain reaction data indicated no GD at the level of sat-1 mRNA. In agreement with the protein data, isolated membranes from both organs exhibited the male-dominant exchange of radiolabeled sulfate for oxalate, whereas higher oxalate in plasma and 24-h urine indicated higher oxalate production and excretion in male rats. Furthermore, the expression of liver, but not renal, sat-1 protein was: unaffected by castration, upregulated by ovariectomy, and downregulated by estrogen or progesterone treatment in males. Therefore, GD (males > females) in the expression of sat-1 protein in rat liver (and, possibly, kidneys) are caused by the female sex-hormone-driven inhibition at the posttranscriptional level. The male-dominant abundance of sat-1 protein in liver may conform to elevated uptake of sulfate and extrusion of oxalate, causing higher plasma oxalate in males. Oxalate is then excreted by the kidneys via the basolateral sat-1 (males > females) and the apical CFEX (Slc26a6; GD unknown) in PT and eliminated in the urine (males > females), where it may contribute to the male-prevailing development of oxalate urolithiasis.

  11. Rubella virion polypeptides

    International Nuclear Information System (INIS)

    Ho-Terry, L.; Cohen, A.

    1982-01-01

    Four polypeptides with molecular weights of 55K, 47K, 45K, and 33K have been resolved by polyacrylamide gel electrophoresis of immune precipitated rubella virus. The 47K and 45K components have similar peptide maps but different isoelectric points so that the same polypeptide may exist in more than one charged form. The 55K and 45K components have similar isoelectric points but different peptide maps showing that similarity of isoelectric point is not evidence of identity. (Author)

  12. Contribution of the organic anion transporter OAT2 to the renal active tubular secretion of creatinine and mechanism for serum creatinine elevations caused by cobicistat

    Science.gov (United States)

    Lepist, Eve-Irene; Zhang, Xuexiang; Hao, Jia; Huang, Jane; Kosaka, Alan; Birkus, Gabriel; Murray, Bernard P; Bannister, Roy; Cihlar, Tomas; Huang, Yong; Ray, Adrian S

    2014-01-01

    Many xenobiotics including the pharmacoenhancer cobicistat increase serum creatinine by inhibiting its renal active tubular secretion without affecting the glomerular filtration rate. This study aimed to define the transporters involved in creatinine secretion, applying that knowledge to establish the mechanism for xenobiotic-induced effects. The basolateral uptake transporters organic anion transporter OAT2 and organic cation transporters OCT2 and OCT3 were found to transport creatinine. At physiologic creatinine concentrations, the specific activity of OAT2 transport was over twofold higher than OCT2 or OCT3, establishing OAT2 as a likely relevant creatinine transporter and further challenging the traditional view that creatinine is solely transported by a cationic pathway. The apical multidrug and toxin extrusion transporters MATE1 and MATE2-K demonstrated low-affinity and high-capacity transport. All drugs known to affect creatinine inhibited OCT2 and MATE1. Similar to cimetidine and ritonavir, cobicistat had the greatest effect on MATE1 with a 50% inhibition constant of 0.99 μM for creatinine transport. Trimethoprim potently inhibited MATE2-K, whereas dolutegravir preferentially inhibited OCT2. Cimetidine was unique, inhibiting all transporters that interact with creatinine. Thus, the clinical observation of elevated serum creatinine in patients taking cobicistat is likely a result of OCT2 transport, facilitating intracellular accumulation, and MATE1 inhibition. PMID:24646860

  13. Up-regulation of the multidrug resistance genes, Mrp1 and Mdr1b, and down-regulation of the organic anion transporter, Mrp2, and the bile salt transporter, Spgp, in endotoxemic rat liver

    NARCIS (Netherlands)

    Vos, T. A.; Hooiveld, G. J.; Koning, H.; Childs, S.; Meijer, D. K.; Moshage, H.; Jansen, P. L.; Müller, M.

    1998-01-01

    Endotoxin-induced cholestasis is mainly caused by an impaired canalicular secretion. Mrp2, the canalicular multispecific organic anion transporter, is strongly down-regulated in this situation, and canalicular bile salt secretion is also reduced. We hypothesized that other adenosine

  14. Up-regulation of the multidrug resistance genes, mrp1 and mdr1b, and down regulation of the organic anion transporter, mrp2, and the bile salt transporter, spgp, in endotoxemic rat liver

    NARCIS (Netherlands)

    Vos, T; Hooiveld, GJE; Konong, H; Childs, S; Meijer, DKF; Moshage, H; Jansen, PLM; Muller, M

    Endotoxin-induced cholestasis is mainly caused by an impaired canalicular secretion. Mrp2, the canalicular multispecific organic anion transporter, is strongly down-regulated in this situation, and canalicular bile salt secretion is also reduced. We hypothesized that other adenosine

  15. Relation between heat of vaporization, ion transport, molar volume, and cation-anion binding energy for ionic liquids.

    Science.gov (United States)

    Borodin, Oleg

    2009-09-10

    A number of correlations between heat of vaporization (H(vap)), cation-anion binding energy (E(+/-)), molar volume (V(m)), self-diffusion coefficient (D), and ionic conductivity for 29 ionic liquids have been investigated using molecular dynamics (MD) simulations that employed accurate and validated many-body polarizable force fields. A significant correlation between D and H(vap) has been found, while the best correlation was found for -log(DV(m)) vs H(vap) + 0.28E(+/-). A combination of enthalpy of vaporization and a fraction of the cation-anion binding energy was suggested as a measure of the effective cohesive energy for ionic liquids. A deviation of some ILs from the reported master curve is explained based upon ion packing and proposed diffusion pathways. No general correlations were found between the ion diffusion coefficient and molecular volume or the diffusion coefficient and cation/anion binding energy.

  16. Regulation of Expression of Renal Organic Anion Transporters OAT1 and OAT3 in a Model of Ischemia/Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Christina Preising

    2015-08-01

    Full Text Available Background: Recently, we gained evidence that impairment of rOat1 and rOat3 expression induced by ischemic acute kidney injury (AKI is mediated by COX metabolites and this suppression might be critically involved in renal damage. Methods: (i Basolateral organic anion uptake into proximal tubular cells after model ischemia and reperfusion (I/R was investigated by fluorescein uptake. The putative promoter sequences from hOAT1 (SLC22A6 and hOAT3 (SCL22A8 were cloned into a reporter plasmid, transfected into HEK cells and (ii transcriptional activity was determined after model ischemia and reperfusion as a SEAP reporter gen assay. Inhibitors or antagonists were applied with the beginning of reperfusion. Results: By using inhibitors of PKA (H89 and PLC (U73122, antagonists of E prostanoid receptor type 2 (AH6809 and type 4 (L161,982, we gained evidence that I/R induced down regulation of organic anion transport is mediated by COX1 metabolites via E prostanoid receptor type 4. The latter signaling was confirmed by application of butaprost (EP2 agonist or TCS2510 (EP4 agonist to control cells. In brief, the latter signaling was verified for the transcriptional activity in the reporter gen assay established. Therein, selective inhibitors for COX1 (SC58125 and COX2 (SC560 were also applied. Conclusion: Our data show (a that COX1 metabolites are involved in the regulation of renal organic anion transport(ers after I/R via the EP4 receptor and (b that this is due to transcriptional regulation of the respective transporters. As the promoter sequences cloned were of human origin and expressed in a human renal epithelial cell line we (c hypothesize that the regulatory mechanisms described after I/R is meaningful for humans as well.

  17. Prebiotic polynucleotides and polypeptides

    Science.gov (United States)

    Orgel, L. E.

    1975-01-01

    Work on the nonenzymatic replication of polynucleotides is discussed emphasizing sequence dependence and showing that alternating polynucleotides should replicate more easily than any others. Experimental work is described showing that polypeptides in which hydrophobic and hydrophilic residues alternate, adopt a beta structure in aqueous solution. The possible relevance of these observations for the evolution of the genetic code is given.

  18. Drug Clearance from Cerebrospinal Fluid Mediated by Organic Anion Transporters 1 (Slc22a6) and 3 (Slc22a8) at Arachnoid Membrane of Rats.

    Science.gov (United States)

    Zhang, Zhengyu; Tachikawa, Masanori; Uchida, Yasuo; Terasaki, Tetsuya

    2018-03-05

    Although arachnoid mater epithelial cells form the blood-arachnoid barrier (BAB), acting as a blood-CSF interface, it has been generally considered that the BAB is impermeable to water-soluble substances and plays a largely passive role. Here, we aimed to clarify the function of transporters at the BAB in regulating CSF clearance of water-soluble organic anion drugs based on quantitative targeted absolute proteomics (QTAP) and in vivo analyses. Protein expression levels of 61 molecules, including 19 ATP-binding-cassette (ABC) transporters and 32 solute-carrier (SLC) transporters, were measured in plasma membrane fraction of rat leptomeninges using QTAP. Thirty-three proteins were detected; others were under the quantification limits. Expression levels of multidrug resistance protein 1 (Mdr1a/P-gp/Abcb1a) and breast cancer resistance protein (Bcrp/Abcg2) were 16.6 and 3.27 fmol/μg protein (51.9- and 9.82-fold greater than in choroid plexus, respectively). Among those organic anion transporters detected only at leptomeninges, not choroid plexus, organic anion transporter 1 (oat1/Slc22a6) showed the greatest expression (2.73 fmol/μg protein). On the other hand, the protein expression level of oat3 at leptomeninges was 6.65 fmol/μg protein, and the difference from choroid plexus was within two-fold. To investigate oat1's role, we injected para-aminohippuric acid (PAH) with or without oat1 inhibitors into cisterna magna (to minimize the contribution of choroid plexus function) of rats. A bulk flow marker, FITC-inulin, was not taken up from CSF up to 15 min, whereas uptake clearance of PAH was 26.5 μL/min. PAH uptake was completely blocked by 3 mM cephalothin (inhibits both oat1 and oat3), while 17% of PAH uptake was inhibited by 0.2 mM cephalothin (selectively inhibits oat3). These results indicate that oat1 and oat3 at the BAB provide a distinct clearance pathway of organic anion drugs from CSF independently of choroid plexus.

  19. Prediction of the overall renal tubular secretion and hepatic clearance of anionic drugs and a renal drug-drug interaction involving organic anion transporter 3 in humans by in vitro uptake experiments.

    Science.gov (United States)

    Watanabe, Takao; Kusuhara, Hiroyuki; Watanabe, Tomoko; Debori, Yasuyuki; Maeda, Kazuya; Kondo, Tsunenori; Nakayama, Hideki; Horita, Shigeru; Ogilvie, Brian W; Parkinson, Andrew; Hu, Zhuohan; Sugiyama, Yuichi

    2011-06-01

    The present study investigated prediction of the overall renal tubular secretion and hepatic clearances of anionic drugs based on in vitro transport studies. The saturable uptake of eight drugs, most of which were OAT3 substrates (rosuvastatin, pravastatin, pitavastatin, valsartan, olmesartan, trichlormethiazide, p-aminohippurate, and benzylpenicillin) by freshly prepared human kidney slices underestimated the overall intrinsic clearance of the tubular secretion; therefore, a scaling factor of 10 was required for in vitro-in vivo extrapolation. We examined the effect of gemfibrozil and its metabolites, gemfibrozil glucuronide and the carboxylic metabolite, gemfibrozil M3, on pravastatin uptake by human kidney slices. The inhibition study using human kidney slices suggests that OAT3 plays a predominant role in the renal uptake of pravastatin. Comparison of unbound concentrations and K(i) values (1.5, 9.1, and 4.0 μM, for gemfibrozil, gemfibrozil glucuronide, and gemfibrozil M3, respectively) suggests that the mechanism of the interaction is due mainly to inhibition by gemfibrozil and gemfibrozil glucuronide. Furthermore, extrapolation of saturable uptake by cryopreserved human hepatocytes predicts clearance comparable with the observed hepatic clearance although fluvastatin and rosuvastatin required a scaling factor of 11 and 6.9, respectively. This study suggests that in vitro uptake assays using human kidney slices and hepatocytes provide a good prediction of the overall tubular secretion and hepatic clearances of anionic drugs and renal drug-drug interactions. It is also recommended that in vitro-in vivo extrapolation be performed in animals to obtain more reliable prediction.

  20. Mosaic HIV envelope immunogenic polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette T. M.; Gnanakaran, S.; Perkins, Simon; Sodroski, Joseph; Haynes, Barton

    2018-01-02

    Disclosed herein are mosaic HIV envelope (Env) polypeptides that can elicit an immune response to HIV (such as cytotoxic T cell (CTL), helper T cell, and/or humoral responses). Also disclosed are sets of the disclosed mosaic Env polypeptides, which include two or more (for example, three) of the polypeptides. Also disclosed herein are methods for treating or inhibiting HIV in a subject including administering one or more of the disclosed immunogenic polypeptides or compositions to a subject infected with HIV or at risk of HIV infection. In some embodiments, the methods include inducing an immune response to HIV in a subject comprising administering to the subject at least one (such as two, three, or more) of the immunogenic polypeptides or at least one (such as two, three, or more) nucleic acids encoding at least one of the immunogenic polypeptides disclosed herein.

  1. Radiolysis of polypeptide

    International Nuclear Information System (INIS)

    Ogura, Isao; Nakamura, Katsuichi; Tanaka, Hiroshi; Takahashi, Katsuhiro; Ozaki, Makoto

    1981-01-01

    Almost the same results were obtained from the additional dipeptide, Gly-DL-Ala and DL-Ala-DL-Phe, by the γ-irradiation as previous report. Tri and tetrapeptide consisted of the same amino acid signified good stability than the others. Every polypeptide composed from sulfur contained amino acid exhaled the smell of hydrogen sulfide by the irradiation. It seemed that the stability by the difference of position of amino group in amino acid increased in order α, β, γ ... amino acid and that by the existence of hydroxyl group became smaller. (author)

  2. Development of Elastomeric Polypeptide BIomaterials

    National Research Council Canada - National Science Library

    Urry, Dan

    1998-01-01

    To design elastic polypeptide biomaterials in order to achieve diverse forms of free energy transduction by these water-miscible hydrophobic folding and assembling macromolecules, thereby to elucidate...

  3. [Dynamics of ultrastructure changes in sheet plate fiber flax with braking transport assimilate by nitrate-anion].

    Science.gov (United States)

    Abdrakhimov, F A; Batasheva, S N; Bakirova, G G; Chikov, V I

    2008-01-01

    Changes in leaf mesophyll cell ultrastructure under nitrate feeding into the apoplast of common flax (Linum usitatissimum L.) in the form of 50 mM KNO3 solution were studied. In 30 min after the beginning of nitrate feeding through the transpiration water stream, swelling of mitochondrial and microbodies, clarification of their matrices, and curling of dictyosome discs into annular structures were observed. These events characterized symplastic domain formed by mesophyll, bundle sheath and phloem parenchyma cells, and were not found in companion cell-sieve element complex. Simultaneously, formation of large central vacuoles in companion cells was noted. Restoration of organelle structures in assimilating cells and phloem parenchyma in 1-2 h after treatment was accompanied by enhancement of morphological changes in phloem elements and companion cells and signs of plasmolysis in the mesophyll cells. It was supposed that the two-phase character of changes in leaf organelle ultrastructure and photosynthesis might reflect duality of leaf cell response to nitrate ion. The rapid alterations of the structure can be coupled with direct influence of the anion on cell metabolism and(or) with signal-regulatory functions of oxidized nitrogen forms, while the slower ones reflect the result of suppression of photoassimilate export from leaves by the anion.

  4. Rational design of organoboron derivatives as chemosensors for fluoride and cyanide anions and charge transport and luminescent materials for organic light-emitting diodes.

    Science.gov (United States)

    Jin, Ruifa; Tang, Shanshan; Luo, Dongmei

    2014-03-01

    The interactions between chemosensors, donor-π-acceptor (D-π-A) dipolar organoboron derivatives, and different (CN⁻, F⁻, Cl⁻, and Br⁻) anions have been theoretically investigated using DFT approaches. Theoretical investigations have been performed to explore the optical, electronic, charge transport, and stability properties of organoboron derivatives as charge transport and luminescent materials for organic light emitting devices (OLEDs). It turned out that the unique selectivity of organoboron derivatives for F⁻/CN⁻ is ascribed to the formation of chemosensors complexes. The frontier molecular orbitals (FMOs) and local density of states analysis have turned out that the vertical electronic transitions of absorption and emission for chemosensors and their F⁻/CN⁻ complexes are characterized as intramolecular charge transfer (ICT). The formation of complexes has effect on the distribution of FMOs and the flowing direction of electronic density for vertical transition. The study of substituent effects suggests that the derivatives with thiophene (2), furan (3), and 1H-pyrrole (4) fragments, are expected to be promising candidates for ratiometric fluorescent fluoride and cyanide chemosensors as well as chromogenic chemosensors, whereas derivatives with pyridine (5) and pyrimidine (6) fragments can serve as chromogenic chemosensors only. Furthermore, all the derivatives are promising luminescent and hole transport materials and 2, 3, 5, and 6 can serve as electron transport materials for OLEDs.

  5. Organic anion and cation SLC22 "drug" transporter (Oat1, Oat3, and Oct1 regulation during development and maturation of the kidney proximal tubule.

    Directory of Open Access Journals (Sweden)

    Thomas F Gallegos

    Full Text Available Proper physiological function in the pre- and post-natal proximal tubule of the kidney depends upon the acquisition of selective permeability, apical-basolateral epithelial polarity and the expression of key transporters, including those involved in metabolite, toxin and drug handling. Particularly important are the SLC22 family of transporters, including the organic anion transporters Oat1 (originally identified as NKT and Oat3 as well as the organic cation transporter Oct1. In ex vivo cultures of metanephric mesenchyme (MM; the embryonic progenitor tissue of the nephron Oat function was evident before completion of nephron segmentation and corresponded with the maturation of tight junctions as measured biochemically by detergent extractability of the tight junction protein, ZO-1. Examination of available time series microarray data sets in the context of development and differentiation of the proximal tubule (derived from both in vivo and in vitro/ex vivo developing nephrons allowed for correlation of gene expression data to biochemically and functionally defined states of development. This bioinformatic analysis yielded a network of genes with connectivity biased toward Hnf4α (but including Hnf1α, hyaluronic acid-CD44, and notch pathways. Intriguingly, the Oat1 and Oat3 genes were found to have strong temporal co-expression with Hnf4α in the cultured MM supporting the notion of some connection between the transporters and this transcription factor. Taken together with the ChIP-qPCR finding that Hnf4α occupies Oat1, Oat3, and Oct1 proximal promoters in the in vivo differentiating rat kidney, the data suggest a network of genes with Hnf4α at its center plays a role in regulating the terminal differentiation and capacity for drug and toxin handling by the nascent proximal tubule of the kidney.

  6. Oatp58Dc contributes to blood-brain barrier function by excluding organic anions from the Drosophila brain.

    Science.gov (United States)

    Seabrooke, Sara; O'Donnell, Michael J

    2013-09-01

    The blood-brain barrier (BBB) physiologically isolates the brain from the blood and, thus, plays a vital role in brain homeostasis. Ion transporters play a critical role in this process by effectively regulating access of chemicals to the brain. Organic anion-transporting polypeptides (Oatps) transport a wide range of amphipathic substrates and are involved in efflux of chemicals across the vertebrate BBB. The anatomic complexity of the vascularized vertebrate BBB, however, creates challenges for experimental analysis of these processes. The less complex structure of the Drosophila BBB facilitates measurement of solute transport. Here we investigate a physiological function for Oatp58Dc in transporting small organic anions across the BBB. We used genetic manipulation, immunocytochemistry, and molecular techniques to supplement a whole animal approach to study the BBB. For this whole animal approach, the traceable small organic anion fluorescein was injected into the hemolymph. This research shows that Oatp58Dc is involved in maintaining a chemical barrier against fluorescein permeation into the brain. Oatp58Dc expression was found in the perineurial and subperineurial glia, as well as in postmitotic neurons. We specifically targeted knockdown of Oatp58Dc expression in the perineurial and subperineurial glia to reveal that Oatp58Dc expression in the perineurial glia is necessary to maintain the barrier against fluorescein influx into the brain. Our results show that Oatp58Dc contributes to maintenance of a functional barrier against fluorescein influx past the BBB into the brain.

  7. Coulomb repulsion in short polypeptides.

    Science.gov (United States)

    Norouzy, Amir; Assaf, Khaleel I; Zhang, Shuai; Jacob, Maik H; Nau, Werner M

    2015-01-08

    Coulomb repulsion between like-charged side chains is presently viewed as a major force that impacts the biological activity of intrinsically disordered polypeptides (IDPs) by determining their spatial dimensions. We investigated short synthetic models of IDPs, purely composed of ionizable amino acid residues and therefore expected to display an extreme structural and dynamic response to pH variation. Two synergistic, custom-made, time-resolved fluorescence methods were applied in tandem to study the structure and dynamics of the acidic and basic hexapeptides Asp6, Glu6, Arg6, Lys6, and His6 between pH 1 and 12. (i) End-to-end distances were obtained from the short-distance Förster resonance energy transfer (sdFRET) from N-terminal 5-fluoro-l-tryptophan (FTrp) to C-terminal Dbo. (ii) End-to-end collision rates were obtained for the same peptides from the collision-induced fluorescence quenching (CIFQ) of Dbo by FTrp. Unexpectedly, the very high increase of charge density at elevated pH had no dynamical or conformational consequence in the anionic chains, neither in the absence nor in the presence of salt, in conflict with the common view and in partial conflict with accompanying molecular dynamics simulations. In contrast, the cationic peptides responded to ionization but with surprising patterns that mirrored the rich individual characteristics of each side chain type. The contrasting results had to be interpreted, by considering salt screening experiments, N-terminal acetylation, and simulations, in terms of an interplay of local dielectric constant and peptide-length dependent side chain charge-charge repulsion, side chain functional group solvation, N-terminal and side chain charge-charge repulsion, and side chain-side chain as well as side chain-backbone interactions. The common picture that emerged is that Coulomb repulsion between water-solvated side chains is efficiently quenched in short peptides as long as side chains are not in direct contact with each

  8. The effect of organic anion transporter 3 inhibitor probenecid on bumetanide levels in the brain: an integrated in vivo microdialysis study in the rat.

    Science.gov (United States)

    Donovan, Maria D; O'Brien, Fionn E; Boylan, Geraldine B; Cryan, John F; Griffin, Brendan T

    2015-04-01

    Recent data highlight the potential of bumetanide as a treatment for neonatal seizures and autism, as it facilitates the excitatory to inhibitory switch in gamma-aminobutyric acid signalling. This study examines the extent of blood-brain barrier (BBB) permeation of bumetanide, a key determinant of the efficacy of centrally acting drugs. Furthermore, the impact of efflux transporter organic anion transporter 3 (oat3) inhibition on bumetanide pharmacokinetics was investigated. Bumetanide levels in extracellular fluid (ECF) and plasma in the presence and absence of oat3 inhibitor probenecid were monitored using integrated microdialysis. Following a bumetanide bolus/continuous infusion of 10 mg/kg and 6 mg/kg/h, bumetanide was detected in hippocampal ECF at the estimated concentration of 131 ± 55 ng/ml. Plasma bumetanide levels were ∼20 mg/l at steady state. Coadministration of probenecid resulted in an increase in bumetanide levels in both ECF and plasma, indicating that oat3 inhibition influences the pharmacokinetics of bumetanide primarily in the periphery. Although bumetanide reached detectable levels in hippocampal ECF, bumetanide concentration in ECF was low relative to systemic concentration. Oat3 inhibition by probenecid resulted in increased bumetanide concentrations in brain and plasma. As an acute treatment in neonatal seizures, the bumetanide/probenecid combination may hold therapeutic potential. © 2014 Royal Pharmaceutical Society.

  9. Natural and azido fatty acids inhibit phosphate transport and activate fatty acid anion uniport mediated by the mitochondrial phosphate carrier

    Czech Academy of Sciences Publication Activity Database

    Engstová, Hana; Žáčková, Markéta; Růžička, Michal; Meinhardt, A.; Hanuš, Jan; Krämer, R.; Ježek, Petr

    2001-01-01

    Roč. 276, č. 7 (2001), s. 4683-4691 ISSN 0021-9258 R&D Projects: GA ČR GA301/95/0620; GA ČR GA301/98/0568; GA MŠk ME 085; GA MŠk ME 389 Grant - others:US(US) Czechoslovak Science and Technology Program 94043 Institutional research plan: CEZ:AV0Z5011922 Keywords : phosphate transport * fatty acids Subject RIV: CE - Biochemistry Impact factor: 7.258, year: 2001

  10. α-Ketoglutarate-related inhibitors of HIF prolyl hydroxylases are substrates of renal organic anion transporters 1 (OAT1) and 4 (OAT4).

    Science.gov (United States)

    Hagos, Yohannes; Schley, Gunnar; Schödel, Johannes; Krick, Wolfgang; Burckhardt, Gerhard; Willam, Carsten; Burckhardt, Birgitta C

    2012-10-01

    2-Oxoglutarate or α-ketoglutarate (αKG) is a substrate of HIF prolyl hydroxylases 1-3 that decrease cellular levels of the hypoxia-inducible factor 1α (HIF-1α) in the presence of oxygen. αKG analogs are applied to stabilize HIF-1α even in the presence of oxygen and thus provide a novel therapeutic option in treating kidney diseases. In the kidneys, the organic anion transporters 1 and 3 (OAT1 and OAT3, respectively) in cooperation with the sodium-dependent dicarboxylate transporter 3 (NaDC3) and the OAT4 might be responsible for the uptake of αKG analogs into and the efflux out of the tubular cells. Using the radiolabelled substrates p-aminohippurate (PAH, OAT1), estrone-3-sulfate (ES; OAT3, OAT4), and succinate (NaDC3), N-oxalylglycine (NOG), dimethyloxalyl glycine (DMOG), 2,4-diethylpyridine dicarboxylate (2,4-DPD), and pyridine-2,4-dicarboxylic acid (PDCA) were tested in cis-inhibition and trans-stimulation experiments. None of these αKG analogs interacted with NaDC3. 2,4-DPD and PDCA inhibited ES uptake by OAT3 moderately. NOG, 2,4-DPD and PDCA, but not DMOG, inhibited PAH uptake by OAT1 significantly. trans-Stimulation experiments and experiments demonstrating stabilization of HIF-1α revealed that NOG and PDCA, but not 2,4-DPD, are translocated by OAT1. All compounds trans-stimulated ES uptake by OAT4, but only PDCA stabilized HIF-1α. The data suggest that OAT1 is involved in the uptake of NOG and PDCA across the basolateral membrane of proximal tubule cells, whereas OAT4 may release these compounds into the primary urine.

  11. Solute carrier organic anion transporter family member 4A1 (SLCO4A1) as a prognosis marker of colorectal cancer.

    Science.gov (United States)

    Ban, Myung Jin; Ji, Sang Hee; Lee, Chi-Kyu; Bae, Sang Byung; Kim, Han Jo; Ahn, Tae Sung; Lee, Moon Soo; Baek, Moo-Jun; Jeong, Dongjun

    2017-08-01

    Solute carrier organic anion transporter family member 4A1 (SLCO4A1) is involved in the transport of various compounds, including sugars, bile salts, organic acids, metal ions, amine compounds, and estrogen. SLCO4A1 is highly expressed in several cancers and a gender bias has been observed in colorectal cancer (CRC). We investigated SLCO4A1 expression, its prognostic value in patients with CRC, and its role in CRC cell proliferation and metastasis. SLCO4A1 expression was assessed by immunohistochemistry (IHC) on specimens from 84 patients with CRC. The association of SLCO4A1 expression with clinicopathological features was examined. To confirm the biological role of SLCO4A1 in CRC, four CRC cell lines expressing SLCO4A1 were used and SLCO4A1 expression was knocked down by siRNA. Cell proliferation, MTT, migration, invasion, and semisolid agar colony formation assays were performed. SLCO4A1 was overexpressed in 32% of the CRC samples. SLCO4A1 overexpression and pathologic T stage were independent prognostic factors of decreased survival (P = 0.021). Kaplan-Meier analysis indicated a decreased cumulative survival for patients highly expressing SLCO4A1 compared to patients showing low SLCO4A1 expression (Log-rank test, P = 0.025). In cell lines, SLCO4A1 knockdown resulted in a significant decrease of viability, invasion, and migration when compared to control cells. Semisolid colony formation assay indicated that SLCO4A1-knocked down cells presented poor carcinogenic abilities compared to control cells. SLCO4A1 may be a valuable marker of poor prognostic for CRC. Furthermore, SLCO4A1 plays an important role in CRC cell proliferation, migration, invasion, and carcinogenesis.

  12. The role of transporters on drug therapy

    Directory of Open Access Journals (Sweden)

    . Ngatidjan

    2016-02-01

    Full Text Available ABSTRACT Pharmacodynamical studies showed that most drugs elicit their effects by acting on 3 kinds of protein molecules known as receptors, enzymes or transporters. Although their detail properties had not been explained for decades the roles of transporters in drug kinetics and dynamics has been well understood, even have been applied in the therapy. Transporters are classified into 2 major classes, the solute carriers (SLC and ATP-binding cassette (ABC families. SLC transporters do not possess ATP binding site property as those of ABC transporters. SLC transporters consist of 3 SLC subfamilies i.e. organic cation transporters (OCTs, organic anion transporters (OATs and organic anion transporting polypeptides (OATPs. In contrast, ABC transporters require ATP hydrolysis to transport substrate across cell membrane. Human ABC-transporters consist of ABCA1- 13, ABCB1-11, ABCC1-12, ABCD1-4, ABCE1, ABCF1-3 and ABCG1-8 subfamily. Although the originally funtion of transporter is to transport specific physiological substrate such as nutrient, hormone, cytokines, neurotransmitters and other physiological subtances across cell membrane the specificity is not restricted to each substrate. Drugs and other xenobiotics which have structural similarity to the physiological substrates are recognized and transported by the related transporters. The competition of them on transporters therefore may lead to the occurence of drug-drug interactions (DDI or drugphysiological substrate interaction in the drug-kinetics phase. Many transporters located in the liver, intestinal and renal epithelial cell membranes involve in the transport of endogenous substance or xenobiotics including drugs play important roles as protective barrier. Since transporters also serve as the targets of drug action it is understood that transporters play important role in the pathogenesis of diseases as well as in the drug therapy of diseases.

  13. Galanin and vasoactive intestinal polypeptide

    DEFF Research Database (Denmark)

    Harling, H; Messell, T; Poulsen, Steen Seier

    1991-01-01

    By immunohistochemistry and double staining technique, almost complete coexistence of galanin-like immunoreactivity (GAL-LI) and vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) was demonstrated in submucosal ganglionic cells and mucosal nerve fibers of the porcine ileum. The rele......By immunohistochemistry and double staining technique, almost complete coexistence of galanin-like immunoreactivity (GAL-LI) and vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) was demonstrated in submucosal ganglionic cells and mucosal nerve fibers of the porcine ileum...

  14. anion dependence

    Indian Academy of Sciences (India)

    SUMAN Das

    batteries with high ene- rgy storage capability is often used as attractive power sources. However, use of Li. + battery in large scale poses some challenges in automobile industry. The limitation is mainly due to their ...... transport properties of the LiPF6 doped 1-ethyl-2,3- dimethyl-imidazolium hexafluorophosphate ionic liq-.

  15. Low doses of ochratoxin A upregulate the protein expression of organic anion transporters Oat1, Oat2, Oat3 and Oat5 in rat kidney cortex

    International Nuclear Information System (INIS)

    Zlender, Vilim; Breljak, Davorka; Ljubojevic, Marija; Flajs, Dubravka; Balen, Daniela; Brzica, Hrvoje; Domijan, Ana-Marija; Peraica, Maja; Fuchs, Radovan; Anzai, Naohiko; Sabolic, Ivan

    2009-01-01

    Mycotoxin ochratoxin A (OTA) is nephrotoxic in various animal species. In rodents, OTA intoxication impairs various proximal tubule (PT) functions, including secretion of p-aminohippurate (PAH), possibly via affecting the renal organic anion (OA) transporters (Oat). However, an effect of OTA on the activity/expression of specific Oats in the mammalian kidney has not been reported. In this work, male rats were gavaged various doses of OTA every 2nd day for 10 days, and in their kidneys we studied: tubule integrity by microscopy, abundance of basolateral (rOat1, rOat3) and brush-border (rOat2, rOat5) rOat proteins by immunochemical methods, and expression of rOats mRNA by RT-PCR. The OTA treatment caused: a) dose-dependent damage of the cells in S3 segments of medullary rays, b) dual effect upon rOats in PT: low doses (50-250 μg OTA/kg b.m.) upregulated the abundance of all rOats, while a high dose (500 μg OTA/kg b.m.) downregulated the abundance of rOat1, and c) unchanged mRNA expression for all rOats at low OTA doses, and its downregulation at high OTA dose. Changes in the expression of renal Oats were associated with enhanced OTA accumulation in tissue and excretion in urine, whereas the indicators of oxidative stress either remained unchanged (malondialdehyde, glutathione, 8-hydroxydeoxyguanosine) or became deranged (microtubules). While OTA accumulation and downregulation of rOats in the kidney are consistent with the previously reported impaired renal PAH secretion in rodents intoxicated with high OTA doses, the post-transcriptional upregulation of Oats at low OTA doses may contribute to OTA accumulation and development of nephrotoxicity.

  16. The glutamate aspartate transporter (GLAST) mediates L-glutamate-stimulated ascorbate-release via swelling-activated anion channels in cultured neonatal rodent astrocytes.

    Science.gov (United States)

    Lane, Darius J R; Lawen, Alfons

    2013-03-01

    Vitamin C (ascorbate) plays important neuroprotective and neuromodulatory roles in the mammalian brain. Astrocytes are crucially involved in brain ascorbate homeostasis and may assist in regenerating extracellular ascorbate from its oxidised forms. Ascorbate accumulated by astrocytes can be released rapidly by a process that is stimulated by the excitatory amino acid, L-glutamate. This process is thought to be neuroprotective against excitotoxicity. Although of potential clinical interest, the mechanism of this stimulated ascorbate-release remains unknown. Here, we report that primary cultures of mouse and rat astrocytes release ascorbate following initial uptake of dehydroascorbate and accumulation of intracellular ascorbate. Ascorbate-release was not due to cellular lysis, as assessed by cellular release of the cytosolic enzyme lactate dehydrogenase, and was stimulated by L-glutamate and L-aspartate, but not the non-excitatory amino acid L-glutamine. This stimulation was due to glutamate-induced cellular swelling, as it was both attenuated by hypertonic and emulated by hypotonic media. Glutamate-stimulated ascorbate-release was also sensitive to inhibitors of volume-sensitive anion channels, suggesting that the latter may provide the conduit for ascorbate efflux. Glutamate-stimulated ascorbate-release was not recapitulated by selective agonists of either ionotropic or group I metabotropic glutamate receptors, but was completely blocked by either of two compounds, TFB-TBOA and UCPH-101, which non-selectively and selectively inhibit the glial Na(+)-dependent excitatory amino acid transporter, GLAST, respectively. These results suggest that an impairment of astrocytic ascorbate-release may exacerbate neuronal dysfunction in neurodegenerative disorders and acute brain injury in which excitotoxicity and/or GLAST deregulation have been implicated.

  17. Glucose-dependent insulinotropic polypeptide

    DEFF Research Database (Denmark)

    Christensen, Mikkel Bring

    2016-01-01

    The hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are secreted by enteroendocrine cells in the intestinal mucosa in response to nutrient ingestion. They are called incretin hormones because of their ability to enhance insulin secretion. However...

  18. Glucose-dependent insulinotropic polypeptide

    DEFF Research Database (Denmark)

    Christensen, Mikkel; Vedtofte, Louise; Holst, Jens Juul

    2011-01-01

    OBJECTIVE To evaluate the glucose dependency of glucose-dependent insulinotropic polypeptide (GIP) effects on insulin and glucagon release in 10 healthy male subjects ([means ± SEM] aged 23 ± 1 years, BMI 23 ± 1 kg/m2, and HbA1c 5.5 ± 0.1%). RESEARCH DESIGN AND METHODS Saline or physiological doses...

  19. Glucose-dependent Insulinotropic Polypeptide

    DEFF Research Database (Denmark)

    Christensen, Mikkel B; Calanna, Salvatore; Holst, Jens Juul

    2014-01-01

    CONTEXT: Patients with type 2 diabetes mellitus (T2DM) have clinically relevant disturbances in the effects of the hormone glucose-dependent insulinotropic polypeptide (GIP). OBJECTIVE: We aimed to evaluate the importance of the prevailing plasma glucose levels for the effect of GIP on responses...

  20. Methods for using polypeptides having cellobiohydrolase activity

    Science.gov (United States)

    Morant, Marc D; Harris, Paul

    2016-08-23

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  1. Aspirin and probenecid inhibit organic anion transporter 3-mediated renal uptake of cilostazol and probenecid induces metabolism of cilostazol in the rat.

    Science.gov (United States)

    Wang, Chong; Wang, Changyuan; Liu, Qi; Meng, Qiang; Cang, Jian; Sun, Huijun; Peng, Jinyong; Ma, Xiaochi; Huo, Xiaokui; Liu, Kexin

    2014-06-01

    This study aimed to evaluate the transporter-mediated renal excretion mechanism for cilostazol and to characterize the mechanism of drug-drug interaction (DDI) between cilostazol and aspirin or probenecid. Concentrations of cilostazol and its metabolites OPC-13015 [6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-2(1H)-quinolinone] and OPC-13213 [3,4-dihydro-6-[4-[1-(trans-4-hydroxycyclohexyl)-1H-tetrazol-5-yl]butoxy]-2-(1H)-quinolinone] in rat biologic or cell samples were measured by liquid chromatography-tandem mass spectrometry. Coadministration with probenecid, benzylpenicillin, or aspirin decreased the cumulative urinary excretion of cilostazol and renal clearance. Concentrations of cilostazol and OPC-13213 in plasma decreased, and the concentration of OPC-13015 increased in the presence of probenecid. By contrast, rat plasma cilostazol, in combination with benzylpenicillin or aspirin, sharply increased, and concentrations of OPC-13015 and OPC-13213 did not change. In urine, OPC-13015 was below the level of detection. The cumulative urinary excretion of OPC-13213 decreased in the presence of probenecid, benzylpenicillin, or aspirin. Cilostazol was distributed in the kidney and liver, with tissue to plasma partition coefficient (Kp) values of 8.4 ml/g and 16.3 ml/g, respectively. Probenecid and aspirin reduced cilostazol distribution in the kidney. Probenecid did not affect cilostazol metabolism in the kidney but increased cilostazol metabolism in the liver, and aspirin had no effect on cilostazol metabolism. Benzylpenicillin, aspirin, and cyclo-trans-4-l-hydroxyprolyl-l-serine (JBP485) reduced cilostazol uptake in kidney slices and human organic anion transporter 3 (hOAT3)-human embryonic kidney 293 (HEK293) cells, whereas p-aminohippuric acid did not. Compared with the vector, hOAT3-HEK293 cells accumulated more cilostazol, whereas hOAT1-HEK293 cells did not. OAT3 and Oat3 play a major role in cilostazol renal excretion, whereas OAT1 and Oat1 do not. Oat3 and Cyp

  2. Phycobilisome structure of porphyridium cruentum: polypeptide composition

    Energy Technology Data Exchange (ETDEWEB)

    Redlinger, T.; Gantt, E.

    1981-01-01

    Purified phycobilisomes of porphyridium cruentum were solubilized in sodium dodecyl sulfate and resolved by sodium dodecyl sulfate-acrylamide gel electrophoresis into nine colored and nine colorless polypeptides. The colored polypeptides accounted for about 84% of the total stainable protein, and the colorless polypeptides accounted for the remaining 16%. Five of the colored polypeptides ranging in molecular weight from 13,300 to 19,500 were identified as the ..cap alpha.. and ..beta.. subunits of allophycocyanin, R-phycocyanin, and phycoerythrin. Three others (29,000-30,500) were orange and are probably related to the ..gamma.. subunit of phycoerythrin. Sequential dissociation of phycobilisomes, and analysis of the polypeptides in each fraction, revealed the association of a 32,500 molecular weight colorless polypeptide with a phycoerythrin fraction. The remaining eight colorless polypeptides were in the core fraction of the phycobilisome, which also was enriched in allophycocyanin.

  3. Transport behaviors of anionic azo dyes at interface between surfactant-modified flax shives and aqueous solution: Synchrotron infrared and adsorption studies

    International Nuclear Information System (INIS)

    Wang, Wenxia; Huang, Guohe; An, Chunjiang; Xin, Xiaying; Zhang, Yan; Liu, Xia

    2017-01-01

    Highlights: • Surfactant modified flax shives for removing anionic azo dyes. • The equilibrium and kinetic studies for the adsorption of anionic azo dyes. • The migration patterns of dye pollutants at flax shive-water interface. • New insights from synchrotron infrared-assisted characterization. • Potential as biomass adsorbent for the removal of dyes from wastewater. - Abstract: From the viewpoint of sustainability, biomass adsorbent has a high potential in pollution control and there is an emerging interest to investigate the behaviors of pollutants at the interface between biomass adsorbent and solution. This study investigated the performance of cetyltrimethylammonium bromide surfactant-modified flax shives (MFS) for removal of anionic azo dyes from aqueous solution. The equilibrium and kinetic analysis for the adsorption of Acid Orange 7 (AO-7), Acid Red 18 (AR-18) and Acid Black 1 (AB-1) on MFS were conducted. The surface of MFS was characterized by synchrotron infrared and SEM analysis. The absorbed amount of three anionic azo dyes varied with the change of adsorbent dosage, pH and ionic strength. The adsorption isotherm data well fit to the Langmuir model. The adsorption process followed the pseudo-second-order kinetics and the liquid film diffusion models. Thermodynamic studies indicated that the adsorption of three anionic azo dyes was spontaneous. The adsorption of AR-18 and AB-1 onto MFS was endothermic while the adsorption of AO-7 was exothermic. The results can help better understand the behaviors of organic pollutants at biomass adsorbent-water interface. They also present the potential of using MFS as a suitable adsorbent for the removal of anionic azo dyes from wastewater.

  4. Transport behaviors of anionic azo dyes at interface between surfactant-modified flax shives and aqueous solution: Synchrotron infrared and adsorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenxia [MOE Key Laboratory of Resources and Environmental Systems Optimization, Institute for Energy, Environment and Sustainability Research, UR-NCEPU, North China Electric Power University, Beijing, 102206 (China); Huang, Guohe, E-mail: huang@iseis.org [MOE Key Laboratory of Resources and Environmental Systems Optimization, Institute for Energy, Environment and Sustainability Research, UR-NCEPU, North China Electric Power University, Beijing, 102206 (China); An, Chunjiang; Xin, Xiaying [Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina, S4S 0A2 (Canada); Zhang, Yan [MOE Key Laboratory of Resources and Environmental Systems Optimization, Institute for Energy, Environment and Sustainability Research, UR-NCEPU, North China Electric Power University, Beijing, 102206 (China); Liu, Xia [Canadian Light Source, Saskatoon, S7N 2V3 (Canada)

    2017-05-31

    Highlights: • Surfactant modified flax shives for removing anionic azo dyes. • The equilibrium and kinetic studies for the adsorption of anionic azo dyes. • The migration patterns of dye pollutants at flax shive-water interface. • New insights from synchrotron infrared-assisted characterization. • Potential as biomass adsorbent for the removal of dyes from wastewater. - Abstract: From the viewpoint of sustainability, biomass adsorbent has a high potential in pollution control and there is an emerging interest to investigate the behaviors of pollutants at the interface between biomass adsorbent and solution. This study investigated the performance of cetyltrimethylammonium bromide surfactant-modified flax shives (MFS) for removal of anionic azo dyes from aqueous solution. The equilibrium and kinetic analysis for the adsorption of Acid Orange 7 (AO-7), Acid Red 18 (AR-18) and Acid Black 1 (AB-1) on MFS were conducted. The surface of MFS was characterized by synchrotron infrared and SEM analysis. The absorbed amount of three anionic azo dyes varied with the change of adsorbent dosage, pH and ionic strength. The adsorption isotherm data well fit to the Langmuir model. The adsorption process followed the pseudo-second-order kinetics and the liquid film diffusion models. Thermodynamic studies indicated that the adsorption of three anionic azo dyes was spontaneous. The adsorption of AR-18 and AB-1 onto MFS was endothermic while the adsorption of AO-7 was exothermic. The results can help better understand the behaviors of organic pollutants at biomass adsorbent-water interface. They also present the potential of using MFS as a suitable adsorbent for the removal of anionic azo dyes from wastewater.

  5. Anion binding in biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Feiters, Martin C [Department of Organic Chemistry, Institute for Molecules and Materials, Faculty of Science, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Meyer-Klaucke, Wolfram [EMBL Hamburg Outstation at DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Kostenko, Alexander V; Soldatov, Alexander V [Faculty of Physics, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 (Russian Federation); Leblanc, Catherine; Michel, Gurvan; Potin, Philippe [Centre National de la Recherche Scientifique and Universite Pierre et Marie Curie Paris-VI, Station Biologique de Roscoff, Place Georges Teissier, BP 74, F-29682 Roscoff cedex, Bretagne (France); Kuepper, Frithjof C [Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland (United Kingdom); Hollenstein, Kaspar; Locher, Kaspar P [Institute of Molecular Biology and Biophysics, ETH Zuerich, Schafmattstrasse 20, Zuerich, 8093 (Switzerland); Bevers, Loes E; Hagedoorn, Peter-Leon; Hagen, Wilfred R, E-mail: m.feiters@science.ru.n [Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft (Netherlands)

    2009-11-15

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L{sub 3} (2p{sub 3/2}) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  6. Anion binding in biological systems

    International Nuclear Information System (INIS)

    Feiters, Martin C; Meyer-Klaucke, Wolfram; Kostenko, Alexander V; Soldatov, Alexander V; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Kuepper, Frithjof C; Hollenstein, Kaspar; Locher, Kaspar P; Bevers, Loes E; Hagedoorn, Peter-Leon; Hagen, Wilfred R

    2009-01-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L 3 (2p 3/2 ) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  7. Anion binding in biological systems

    Science.gov (United States)

    Feiters, Martin C.; Meyer-Klaucke, Wolfram; Kostenko, Alexander V.; Soldatov, Alexander V.; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Küpper, Frithjof C.; Hollenstein, Kaspar; Locher, Kaspar P.; Bevers, Loes E.; Hagedoorn, Peter-Leon; Hagen, Wilfred R.

    2009-11-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L3 (2p3/2) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  8. Transport behaviors of anionic azo dyes at interface between surfactant-modified flax shives and aqueous solution: Synchrotron infrared and adsorption studies

    Science.gov (United States)

    Wang, Wenxia; Huang, Guohe; An, Chunjiang; Xin, Xiaying; Zhang, Yan; Liu, Xia

    2017-05-01

    From the viewpoint of sustainability, biomass adsorbent has a high potential in pollution control and there is an emerging interest to investigate the behaviors of pollutants at the interface between biomass adsorbent and solution. This study investigated the performance of cetyltrimethylammonium bromide surfactant-modified flax shives (MFS) for removal of anionic azo dyes from aqueous solution. The equilibrium and kinetic analysis for the adsorption of Acid Orange 7 (AO-7), Acid Red 18 (AR-18) and Acid Black 1 (AB-1) on MFS were conducted. The surface of MFS was characterized by synchrotron infrared and SEM analysis. The absorbed amount of three anionic azo dyes varied with the change of adsorbent dosage, pH and ionic strength. The adsorption isotherm data well fit to the Langmuir model. The adsorption process followed the pseudo-second-order kinetics and the liquid film diffusion models. Thermodynamic studies indicated that the adsorption of three anionic azo dyes was spontaneous. The adsorption of AR-18 and AB-1 onto MFS was endothermic while the adsorption of AO-7 was exothermic. The results can help better understand the behaviors of organic pollutants at biomass adsorbent-water interface. They also present the potential of using MFS as a suitable adsorbent for the removal of anionic azo dyes from wastewater.

  9. Anion conductance of the human red cell is carried by a maxi-anion channel

    DEFF Research Database (Denmark)

    Glogowska, Edyta; Dyrda, Agnieszka; Cueff, Anne

    2010-01-01

    Historically, the anion transport through the human red cell membrane has been perceived to be mediated by Band 3, in the two-component concept with the large electroneutral anion exchange accompanied by the conductance proper, which dominated the total membrane conductance. The status of anion...... that the diversity of anionic channel activities recorded in human erythrocytes corresponds to different kinetic modalities of a unique type of maxi-anion channel with multiple conductance levels and probably multiple gating properties and pharmacology, depending on conditions. It demonstrates the role of activator...... played by serum in the recruitment of multiple new conductance levels showing very complex kinetics and gating properties upon serum addition. These channels, which seem to be dormant under normal physiological conditions, are potentially activable and could confer a far higher anion conductance...

  10. Recombinant expression of backbone-cyclized polypeptides.

    Science.gov (United States)

    Borra, Radhika; Camarero, Julio A

    2013-09-01

    Here we review the different biochemical approaches available for the expression of backbone-cyclized polypeptides, including peptides and proteins. These methods allow for the production of circular polypeptides either in vitro or in vivo using standard recombinant DNA expression techniques. Polypeptide circularization provides a valuable tool to study the effects of topology on protein stability and folding kinetics. Furthermore, having biosynthetic access to backbone-cyclized polypeptides makes the production of genetically encoded libraries of cyclic polypeptides possible. The production of such libraries, which was previously restricted to the domain of synthetic chemistry, now offers biologists access to highly diverse and stable molecular libraries that can be screened using high-throughput methods for the rapid selection of novel cyclic polypeptide sequences with new biological activities. Copyright © 2013 Wiley Periodicals, Inc.

  11. Advances in anion supramolecular chemistry: from recognition to chemical applications.

    Science.gov (United States)

    Evans, Nicholas H; Beer, Paul D

    2014-10-27

    Since the start of this millennium, remarkable progress in the binding and sensing of anions has been taking place, driven in part by discoveries in the use of hydrogen bonding, as well as the previously under-exploited anion-π interactions and halogen bonding. However, anion supramolecular chemistry has developed substantially beyond anion recognition, and now encompasses a diverse range of disciplines. Dramatic advance has been made in the anion-templated synthesis of macrocycles and interlocked molecular architectures, while the study of transmembrane anion transporters has flourished from almost nothing into a rapidly maturing field of research. The supramolecular chemistry of anions has also found real practical use in a variety of applications such as catalysis, ion extraction, and the use of anions as stimuli for responsive chemical systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Production of Elastomeric Polypeptides for Materials Characterizations

    National Research Council Canada - National Science Library

    Urry, Dan

    2004-01-01

    .... Specifically, this effort is to provide 100 gram quantities of six and 10 gram quantities of an additional nine elastomeric polypeptides for conventional and specialized materials characterizations...

  13. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, Kathryn M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-06

    This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through the large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.

  14. Effect of humic acid on uranium(VI) retention and transport through quartz columns with varying pH and anion type.

    Science.gov (United States)

    Du, Liang; Li, Shicheng; Li, Xiaolong; Wang, Ping; Huang, Zhaoya; Tan, Zhaoyi; Liu, Chunli; Liao, Jiali; Liu, Ning

    2017-10-01

    Humic acid (HA) 1 is ubiquitous in the environment and is an important factor in the migration behavior of U(VI) in the geological medium. The present work investigated the effect of HA on the migration behavior of U(VI) using quartz column experiments at different pH values and in the presence of various anions. The U(VI) adsorption characteristics and speciation were also studied to illuminate further the migration behavior of U(VI). Our results indicated that, at pH 6.0, HA slightly increased the migration velocity of U(VI) during the initial phase and reduced the quantity of eluted U(VI) because of the formation of HA-U(VI). The relative concentration (c/c 0 ) of U(VI)was higher in the HA-U system at pH 8.0 than that at pH 5.0 because of the higher solubility of HA in basic solutions and the difference in charge of HA-U(VI). In the U-HA-anion system at pH 6.0, the breakthrough pore volumes (PVs 2 ) of U(VI) in electrolytes containing Cl - and SO 4 2- anions (PV = 8) are much higher than for solutions containing phosphate (PV = 3), while the HA migration behavior was not significantly affected by the type of anion. Thus, the fast migration of U(VI) under HA and phosphate was attributed to phosphate rather than HA. This result suggests that phosphate should be given more attention in predictions of U(VI) migration, especially in regions with high groundwater phosphate content. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Methods for engineering polypeptide variants via somatic hypermutation and polypeptide made thereby

    Science.gov (United States)

    Tsien, Roger Y; Wang, Lei

    2015-01-13

    Methods using somatic hypermutation (SHM) for producing polypeptide and nucleic acid variants, and nucleic acids encoding such polypeptide variants are disclosed. Such variants may have desired properties. Also disclosed are novel polypeptides, such as improved fluorescent proteins, produced by the novel methods, and nucleic acids, vectors, and host cells comprising such vectors.

  16. Assessment of Amino Acid/Drug Transporters for Renal Transport of [18F]Fluciclovine (anti-[18F]FACBC in Vitro

    Directory of Open Access Journals (Sweden)

    Masahiro Ono

    2016-10-01

    Full Text Available [18F]Fluciclovine (trans-1-amino-3-[18F]fluorocyclobutanecarboxylic acid; anti-[18F]FACBC, a positron emission tomography tracer used for the diagnosis of recurrent prostate cancer, is transported via amino acid transporters (AATs with high affinity (Km: 97–230 μM. However, the mechanism underlying urinary excretion is unknown. In this study, we investigated the involvement of AATs and drug transporters in renal [18F]fluciclovine reuptake. [14C]Fluciclovine (trans-1-amino-3-fluoro[1-14C]cyclobutanecarboxylic acid was used because of its long half-life. The involvement of AATs in [14C]fluciclovine transport was measured by apical-to-basal transport using an LLC-PK1 monolayer as model for renal proximal tubules. The contribution of drug transporters herein was assessed using vesicles/cells expressing the drug transporters P-glycoprotein (P-gp, breast cancer resistance protein (BCRP, multidrug resistance-associated protein 4 (MRP4, organic anion transporter 1 (OAT1, organic anion transporter 3 (OAT3 , organic cation transporter 2 (OCT2, organic anion transporting polypeptide 1B1 (OATP1B1, and organic anion transporting polypeptide 1B3 (OATP1B3. The apical-to-basal transport of [14C]fluciclovine was attenuated by l-threonine, the substrate for system alanine-serine-cysteine (ASC AATs. [14C]Fluciclovine uptake by drug transporter-expressing vesicles/cells was not significantly different from that of control vesicles/cells. Fluciclovine inhibited P-gp, MRP4, OAT1, OCT2, and OATP1B1 (IC50 > 2.95 mM. Therefore, system ASC AATs may be partly involved in the renal reuptake of [18F]fluciclovine. Further, given that [18F]fluciclovine is recognized as an inhibitor with millimolar affinity for the tested drug transporters, slow urinary excretion of [18F]fluciclovine may be mediated by system ASC AATs, but not by drug transporters.

  17. Ordered biological nanostructures formed from chaperonin polypeptides

    Science.gov (United States)

    Trent, Jonathan D. (Inventor); McMillan, R. Andrew (Inventor); Kagawa, Hiromi (Inventor); Paavola, Chad D. (Inventor)

    2010-01-01

    The following application relates to nanotemplates, nanostructures, nanoarrays and nanodevices formed from wild-type and mutated chaperonin polypeptides, methods of producing such compositions, methods of using such compositions and particular chaperonin polypeptides that can be utilized in producing such compositions.

  18. Polypeptides having catalase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ye; Duan, Junxin; Zhang, Yu; Tang, Lan

    2017-05-02

    Provided are isolated polypeptides having catalase activity and polynucleotides encoding the polypeptides. Also provided are nucleic acid constructs, vectors and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  19. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Science.gov (United States)

    Spodsberg, Nikolaj

    2015-07-14

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  20. Hybrid polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ye; Shaghasi, Tarana

    2016-11-01

    The present invention provides hybrid polypeptides having cellobiohydrolase activity. The present invention also provides polynucleotides encoding the hybrid polypeptides; nucleic acid constructs, vectors and host cells comprising the polynucleotides; and processes of using the hybrid polypeptides.

  1. Polypeptides having beta-xylosidase activity and polynucleotides encoding same

    Science.gov (United States)

    Liu, Ye; Tang, Lan; Zhang, Yu; Duan, Junxin

    2017-04-18

    Provided are isolated polypeptides having beta-xylosidase activity and polynucleotides encoding the polypeptides. Also provided are nucleic acid constructs, vectors and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  2. Polypeptides having beta-glucosidase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ye; Duan, Junxin; Zhang, Yu; Tang, Lan

    2017-09-26

    Provided are isolated polypeptides having beta-glucosidase activity and polynucleotides encoding the polypeptides. Also provided are nucleic acid constructs, vectors and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  3. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj

    2016-06-28

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  4. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj

    2016-12-13

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  5. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj

    2017-11-21

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  6. Polypeptides having endoglucanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Liu, Ye; Duan, Junxin; Tang, Lan

    2017-07-18

    Provided are isolated polypeptides having endoglucanase activity and isolated polynucleotides encoding the polypeptides. Also provided are nucleic acid constructs, vectors and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  7. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Science.gov (United States)

    Spodsberg, Nikolaj

    2015-11-17

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  8. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Tang, Lan; Henriksen, Svend Hostgaard Bang

    2016-05-17

    The present invention provides isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also provides nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  9. Polypeptides having xylanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj

    2017-05-02

    The present invention relates to isolated polypeptides having xylanase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  10. Polypeptides having cellobiohydrolase activitiy and polynucleotides encoding same

    Science.gov (United States)

    Liu, Ye; Tang, Lan; Duan, Junxin

    2015-12-15

    The present invention provides isolated polypeptides having cellobiohydrolase activity and isolated polynucleotides encoding the polypeptides. The invention also provides nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  11. Polypeptides having xylanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj

    2018-02-06

    The present invention relates to isolated polypeptides having xylanase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  12. Drug Transporter Expression and Activity in Human Hepatoma HuH-7 Cells

    Directory of Open Access Journals (Sweden)

    Elodie Jouan

    2016-12-01

    Full Text Available Human hepatoma cells may represent a valuable alternative to the use of human hepatocytes for studying hepatic drug transporters, which is now a regulatory issue during drug development. In the present work, we have characterized hepatic drug transporter expression, activity and regulation in human hepatoma HuH-7 cells, in order to determine the potential relevance of these cells for drug transport assays. HuH-7 cells displayed notable multidrug resistance-associated protein (MRP activity, presumed to reflect expression of various hepatic MRPs, including MRP2. By contrast, they failed to display functional activities of the uptake transporters sodium taurocholate co-transporting polypeptide (NTCP, organic anion-transporting polypeptides (OATPs and organic cation transporter 1 (OCT1, and of the canalicular transporters P-glycoprotein and breast cancer resistance protein (BCRP. Concomitantly, mRNA expressions of various sinusoidal and canalicular hepatic drug transporters were not detected (NTCP, OATP1B1, organic anion transporter 2 (OAT2, OCT1 and bile salt export pump or were found to be lower (OATP1B3, OATP2B1, multidrug and toxin extrusion protein 1, BCRP and MRP3 in hepatoma HuH-7 cells than those found in human hepatocytes, whereas other transporters such as OAT7, MRP4 and MRP5 were up-regulated. HuH-7 cells additionally exhibited farnesoid X receptor (FXR- and nuclear factor erythroid 2-related factor 2 (Nrf2-related up-regulation of some transporters. Such data indicate that HuH-7 cells, although expressing rather poorly some main hepatic drug transporters, may be useful for investigating interactions of drugs with MRPs, notably MRP2, and for studying FXR- or Nrf2-mediated gene regulation.

  13. Transporters and drug-drug interactions: important determinants of drug disposition and effects.

    Science.gov (United States)

    König, Jörg; Müller, Fabian; Fromm, Martin F

    2013-07-01

    Uptake and efflux transporters determine plasma and tissue concentrations of a broad variety of drugs. They are localized in organs such as small intestine, liver, and kidney, which are critical for drug absorption and elimination. Moreover, they can be found in important blood-tissue barriers such as the blood-brain barrier. Inhibition or induction of drug transporters by coadministered drugs can alter pharmacokinetics and pharmacodynamics of the victim drugs. This review will summarize in particular clinically observed drug-drug interactions attributable to inhibition or induction of intestinal export transporters [P-glycoprotein (P-gp), breast cancer resistance protein (BCRP)], to inhibition of hepatic uptake transporters [organic anion transporting polypeptides (OATPs)], or to inhibition of transporter-mediated [organic anion transporters (OATs), organic cation transporter 2 (OCT2), multidrug and toxin extrusion proteins (MATEs), P-gp] renal secretion of xenobiotics. Available data on the impact of nutrition on transport processes as well as genotype-dependent, transporter-mediated drug-drug interactions will be discussed. We will also present and discuss data on the variable extent to which information on the impact of transporters on drug disposition is included in summaries of product characteristics of selected countries (SPCs). Further work is required regarding a better understanding of the role of the drug metabolism-drug transport interplay for drug-drug interactions and on the extrapolation of in vitro findings to the in vivo (human) situation.

  14. Role of glutathione transport processes in kidney function

    International Nuclear Information System (INIS)

    Lash, Lawrence H.

    2005-01-01

    The kidneys are highly dependent on an adequate supply of glutathione (GSH) to maintain normal function. This is due, in part, to high rates of aerobic metabolism, particularly in the proximal tubules. Additionally, the kidneys are potentially exposed to high concentrations of oxidants and reactive electrophiles. Renal cellular concentrations of GSH are maintained by both intracellular synthesis and transport from outside the cell. Although function of specific carriers has not been definitively demonstrated, it is likely that multiple carriers are responsible for plasma membrane transport of GSH. Data suggest that the organic anion transporters OAT1 and OAT3 and the sodium-dicarboxylate 2 exchanger (SDCT2 or NaDC3) mediate uptake across the basolateral plasma membrane (BLM) and that the organic anion transporting polypeptide OATP1 and at least one of the multidrug resistance proteins mediate efflux across the brush-border plasma membrane (BBM). BLM transport may be used pharmacologically to provide renal proximal tubular cells with exogenous GSH to protect against oxidative stress whereas BBM transport functions physiologically in turnover of cellular GSH. The mitochondrial GSH pool is derived from cytoplasmic GSH by transport into the mitochondrial matrix and is mediated by the dicarboxylate and 2-oxoglutarate exchangers. Maintenance of the mitochondrial GSH pool is critical for cellular and mitochondrial redox homeostasis and is important in determining susceptibility to chemically induced apoptosis. Hence, membrane transport processes are critical to regulation of renal cellular and subcellular GSH pools and are determinants of susceptibility to cytotoxicity induced by oxidants and electrophiles

  15. The Influence of Active Transport Systems on Morphine -6-Glucuronide Transport in MDCKII and MDCK-PGP Cells

    Directory of Open Access Journals (Sweden)

    SO. Mashayekhi

    2011-12-01

    Full Text Available Background and the purpose of the study: Morphine-6-glucuronide (M6G is a potent metabolite of morphine which has high penetration into the brain despite its high polarity, which could be the result of an active transport system involved in M6G transport through blood brain barrier. Examples of such transporters are p-glycoprotein (PGP, probenecid-sensitive transport mechanism, multidrug resistance related protein 1-3, the organic anion transporter family, and the organic anion transporter polypeptide family. The aim of present study was to elucidate the mechanisms involved in transporting morphine's potent metabolite, M6G.Methods: M6G permeability via two cell lines; MDCKII and MDCK-PGP, was compared with that of sucrose. M6G transport was examined in different concentrations and in the presence of inhibitors of different transport systems such as cyclosporine, digoxin and probenecid. M6G concentration was measured using ELISA assay. The method was sensitive, reliable and reproducible.Results: The results confirmed that M6G could cross a layer of MDCK II or MDR-PGP cells more than sucrose could. It was also observed that M6G is a PGP transporter substrate. Its permeability was increased by the use of a PGP expressed cell line, and also in the presence of a strong PGP inhibitor. Digoxin related transporters such as Oatp2 may also involved in transport of M6G. M6G seemed to be a glucose transporter 1 substrate, but was not a substrate to probenecid sensitive transporters.Major conclusion: It is concluded that different transporters are responsible for M6G transports via different membrane, which could have effects on its pharmacokinetics or pharmacodynamics.

  16. Preparation of polypeptides comprising multiple TAA peptides.

    Science.gov (United States)

    Ni, Bing; Jia, Zhengcai; Wu, Yuzhang

    2014-01-01

    Polypeptides consisting of multiple tumor-associated antigen epitopes (multiepitope peptides) are commonly used as therapeutic peptide cancer vaccines in experimental studies and clinical trials. These methods include polypeptides composed of multiple major histocompatibility complex (MHC) class I-restricted cytotoxic T cell (CTL) epitopes and those containing multiple CTL epitopes and one T helper (Th) epitope. This chapter describes a complete set of methods for preparing multiepitope peptides and branched multiple antigen peptides (MAPs), including sequence design, peptide synthesis, purification, preservation, and the preparation of polypeptide solutions.

  17. The Generation of Dehydroalanine Residues in Protonated Polypeptides: Ion/Ion Reactions for Introducing Selective Cleavages

    Science.gov (United States)

    Peng, Zhou; Bu, Jiexun; McLuckey, Scott A.

    2017-09-01

    We examine a gas-phase approach for converting a subset of amino acid residues in polypeptide cations to dehydroalanine (Dha). Subsequent activation of the modified polypeptide ions gives rise to specific cleavage N-terminal to the Dha residue. This process allows for the incorporation of selective cleavages in the structural characterization of polypeptide ions. An ion/ion reaction within the mass spectrometer between a multiply protonated polypeptide and the sulfate radical anion introduces a radical site into the multiply protonated polypeptide reactant. Subsequent collisional activation of the polypeptide radical cation gives rise to radical side chain loss from one of several particular amino acid side chains (e.g., leucine, asparagine, lysine, glutamine, and glutamic acid) to yield a Dha residue. The Dha residues facilitate preferential backbone cleavages to produce signature c- and z-ions, demonstrated with cations derived from melittin, mechano growth factor (MGF), and ubiquitin. The efficiencies for radical side chain loss and for subsequent generation of specific c- and z-ions have been examined as functions of precursor ion charge state and activation conditions using cations of ubiquitin as a model for a small protein. It is noted that these efficiencies are not strongly dependent on ion trap collisional activation conditions but are sensitive to precursor ion charge state. Moderate to low charge states show the greatest overall yields for the specific Dha cleavages, whereas small molecule losses (e.g., water/ammonia) dominate at the lowest charge states and proton catalyzed amide bond cleavages that give rise to b- and y-ions tend to dominate at high charge states. [Figure not available: see fulltext.

  18. Tissue polypeptide antigen activity in cerebrospinal fluid

    DEFF Research Database (Denmark)

    Bach, F; Söletormos, Georg; Dombernowsky, P

    1991-01-01

    Tissue polypeptide antigen (TPpA) in the cerebrospinal fluid (CSF) was measured in 59 consecutive breast cancer patients with suspected central nervous system (CNS) metastases. Subsequently, we determined that 13 patients had parenchymal brain metastases, 10 had leptomeningeal carcinomatosis...

  19. Biolubricant Polypeptides and Therapeutic Uses Thereof

    NARCIS (Netherlands)

    Sharma, Prashant; Herrmann, Andreas; Kolbe, Anke; Veeregowda, Deepak; van der Mei, Henderina; Busscher, Hendrik

    2016-01-01

    The invention relates to the field of medicine. In particular, it relates to recombinant cationic polypeptides and their use as biolubricant. Provided is a biolubricant substance comprising the amino acid sequence[(GKGVP)9]n, wherein n is ≧5.

  20. Polypeptides having laccase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ye; Tang, Lan; Duan, Junxin; Zhang, Yu

    2017-08-22

    The present invention relates to isolated polypeptides having laccase activity and polynucleotides encoding the polypeptides and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  1. Transport properties of anion exchange membranes in contact with organic ions. Part 2. Influence of the size of the aromatic chain; Proprietes de transport de membranes echangeuses d'anions en presence d'ions organiques. Partie 2. Influence de la taille de la chaine aromatique

    Energy Technology Data Exchange (ETDEWEB)

    Delimi, R. [Lab. de Traitement des eaux, Institut de Chimie, Universite de Badji Mokhtar, Annaba (Algeria); Sandeaux, J.; Sandeaux, R.; Pourcelly, G. [Montpellier-2 Univ., Institut Europeen des Mambranes, UMR 5635, 34 (France)

    2000-12-01

    Electrodialysis (process using ion exchange membranes and an electric field) is used for the treatment of waters and industrial effluents. In this work, the physico-chemical properties of an anion exchange membrane (ADS, Solvay) were studied in aqueous solutions containing both a mineral salt (10{sup -1} M NaCl) and an organic salt (10{sup -2} to 10{sup -1} M). The organic salt was a sodium carboxylate or sulfonate bearing one or two aromatic rings. Measurements of ion exchange, water content, electric resistance, self-diffusion and electro-diffusion fluxes were performed. According to the concentration, the organic anions with highly hydrophobic character can induce a poisoning of the membrane. (authors)

  2. Inhibitory effects of p-aminohippurate and probenecid on the renal clearance of adefovir and benzylpenicillin as probe drugs for organic anion transporter (OAT) 1 and OAT3 in humans.

    Science.gov (United States)

    Maeda, Kazuya; Tian, Ying; Fujita, Tomoe; Ikeda, Yasuhiko; Kumagai, Yuji; Kondo, Tsunenori; Tanabe, Kazunari; Nakayama, Hideki; Horita, Shigeru; Kusuhara, Hiroyuki; Sugiyama, Yuichi

    2014-08-01

    Probe substrates for, and inhibitors of, specific transporters are desired to evaluate quantitatively the in vivo functions of transporters in humans. Based on published data, adefovir and benzylpenicillin were selected as organic anion transporter (OAT) 1- and OAT3-selective probe substrates, respectively. In human kidney slices, probenecid potently inhibited the uptake of both adefovir and benzylpenicillin with inhibition constant (Ki) values of 18.6±5.1 and 12.6±4.2μM, respectively, whereas p-aminohippurate (PAH) preferentially inhibited adefovir uptake. A clinical drug-interaction study involving healthy subjects was performed to investigate the dose-dependent inhibition potencies of probenecid and PAH on the renal clearance of the probe substrates. Adefovir or benzylpenicillin was coadministered with different oral doses of probenecid (500, 750, or 1500mg) or intravenous PAH infusion rates (70, 120, or 210mg/min/person) to the same subject using a crossover design. The renal clearance of adefovir was reduced by 45% and 46% in the subjects treated with the maximum dose of probenecid and PAH, respectively, which was in accordance with the results of in vitro inhibition study. On the other hand, renal clearance of benzylpenicillin was reduced by 78% in the subjects treated with the maximum dose of probenecid (1500mg), which could be explained by its in vitro Ki values. However, PAH unexpectedly increased the renal clearance of benzylpenicillin by 47%. These results suggest that adefovir and benzylpenicillin can be used as probe drugs for OAT1 and OAT3, respectively, and that PAH can be used to investigate the role of OAT1 in the urinary excretion of drugs in humans, whereas it may modulate other transport processes in the kidney. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Determination of Hydraulic and Transport Parameters of Organic Chemical and Inorganic Anions Solutes for Unfractured Cores of Berea Sandstone Using a Hydraulic Coreholder

    Science.gov (United States)

    Blanford, W. J.; Neil, L.

    2017-12-01

    To better evaluate the potential for toxic organic chemicals to migrate upward through the rock strata from hydraulic fracturing zones and into groundwater resources, a series of miscible displacement solute transport studies of cores of Berea Sandstone have been conducted using hydrostatic core holder. These tests involved passing aqueous solutions with natural background level of salts using a high pressure LC pump through 2 in wide by 3 in long unfractured cores held within the holder. Relative solute transport of 100 to 500ml pulses of target solutes including a series of chlorinated solvents and methylated benzenes was measured through in-line UV and fluorescence detectors and manual sampling and analysis with GCMS. The results found these sandstones to result in smooth ideal shaped breakthrough curves. Analysis with 1D transport models (CXTFIT) of the results found strong correlation with chemical parameters (diffusion coefficients, aqueous solubility, and octanol-water partitioning coefficients) showing that these parameter and QSPR relationships can be used to make accurate predictions for such a system. In addition to the results of the studies, lessons learned from this novel use of a coreholder for evaluation of porosity, water-saturated permeability, and solute transport of these sandstones (K = 1.5cm/day) and far less permeable sandstones samples (K = 0.15 cm/yr) from a hydraulic fracturing site in central Pennsylvania will be presented.

  4. Carbohydrate degrading polypeptide and uses thereof

    Science.gov (United States)

    Sagt, Cornelis Maria Jacobus; Schooneveld-Bergmans, Margot Elisabeth Francoise; Roubos, Johannes Andries; Los, Alrik Pieter

    2015-10-20

    The invention relates to a polypeptide having carbohydrate material degrading activity which comprises the amino acid sequence set out in SEQ ID NO: 2 or an amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 1 or SEQ ID NO: 4, or a variant polypeptide or variant polynucleotide thereof, wherein the variant polypeptide has at least 96% sequence identity with the sequence set out in SEQ ID NO: 2 or the variant polynucleotide encodes a polypeptide that has at least 96% sequence identity with the sequence set out in SEQ ID NO: 2. The invention features the full length coding sequence of the novel gene as well as the amino acid sequence of the full-length functional protein and functional equivalents of the gene or the amino acid sequence. The invention also relates to methods for using the polypeptide in industrial processes. Also included in the invention are cells transformed with a polynucleotide according to the invention suitable for producing these proteins.

  5. Ca-C backbone fragmentation dominates in electron detachment dissociation of gas-phase polypeptide polyanions

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Silivra, Oleg A; Ivonin, Igor A

    2005-01-01

    the dissociation of oxidized radical anions [M-nH]((n-1)-*. We demonstrate that C(alpha)-C cleavages, which are otherwise rarely observed in tandem mass spectrometry, can account for most of the backbone fragmentation, with even-electron x fragments dominating over radical a* ions. Ab initio calculations at the B3......Fragmentation of peptide polyanions by electron detachment dissociation (EDD) has been induced by electron irradiation of deprotonated polypeptides [M-nH](n-) with >10 eV electrons. EDD has been found to lead preferentially to a* and x fragment ions (C(alpha)-C backbone cleavage) arising from...

  6. Anion-π catalysis.

    Science.gov (United States)

    Zhao, Yingjie; Beuchat, César; Domoto, Yuya; Gajewy, Jadwiga; Wilson, Adam; Mareda, Jiri; Sakai, Naomi; Matile, Stefan

    2014-02-05

    The introduction of new noncovalent interactions to build functional systems is of fundamental importance. We here report experimental and theoretical evidence that anion-π interactions can contribute to catalysis. The Kemp elimination is used as a classical tool to discover conceptually innovative catalysts for reactions with anionic transition states. For anion-π catalysis, a carboxylate base and a solubilizer are covalently attached to the π-acidic surface of naphthalenediimides. On these π-acidic surfaces, transition-state stabilizations up to ΔΔGTS = 31.8 ± 0.4 kJ mol(-1) are found. This value corresponds to a transition-state recognition of KTS = 2.7 ± 0.5 μM and a catalytic proficiency of 3.8 × 10(5) M(-1). Significantly increasing transition-state stabilization with increasing π-acidity of the catalyst, observed for two separate series, demonstrates the existence of "anion-π catalysis." In sharp contrast, increasing π-acidity of the best naphthalenediimide catalysts does not influence the more than 12 000-times weaker substrate recognition (KM = 34.5 ± 1.6 μM). Together with the disappearance of Michaelis-Menten kinetics on the expanded π-surfaces of perylenediimides, this finding supports that contributions from π-π interactions are not very important for anion-π catalysis. The linker between the π-acidic surface and the carboxylate base strongly influences activity. Insufficient length and flexibility cause incompatibility with saturation kinetics. Moreover, preorganizing linkers do not improve catalysis much, suggesting that the ideal positioning of the carboxylate base on the π-acidic surface is achieved by intramolecular anion-π interactions rather than by an optimized structure of the linker. Computational simulations are in excellent agreement with experimental results. They confirm, inter alia, that the stabilization of the anionic transition states (but not the neutral ground states) increases with the π-acidity of the

  7. Overexpression of Interleukin-4 in the Thyroid of Transgenic Mice Upregulates the Expression of Duox1 and the Anion Transporter Pendrin.

    Science.gov (United States)

    Eskalli, Zineb; Achouri, Younes; Hahn, Stephan; Many, Marie-Christine; Craps, Julie; Refetoff, Samuel; Liao, Xiao-Hui; Dumont, Jacques E; Van Sande, Jacqueline; Corvilain, Bernard; Miot, Françoise; De Deken, Xavier

    2016-10-01

    The dual oxidases (Duox) are involved in hydrogen peroxide generation, which is essential for thyroid hormone synthesis, and therefore they are markers of thyroid function. During inflammation, cytokines upregulate DUOX gene expression in the airway and the intestine, suggesting a role for these proteins in innate immunity. It was previously demonstrated that interleukin-4 (IL-4) upregulates DUOX gene expression in thyrocytes. Although the role of IL-4 in autoimmune thyroid diseases has been studied extensively, the effects of IL-4 on thyroid physiology remain largely unknown. Therefore, a new animal model was generated to study the impact of IL-4 on thyroid function. Transgenic (Thyr-IL-4) mice with thyroid-targeted expression of murine IL-4 were generated. Transgene expression was verified at the mRNA and protein level in thyroid tissues and primary cultures. The phenotype of the Thyr-IL-4 animals was characterized by measuring serum thyroxine (T4) and thyrotropin levels and performing thyroid morphometric analysis, immunohistochemistry, whole transcriptome sequencing, quantitative reverse transcription polymerase chain reaction, and ex vivo thyroid function assays. Thyrocytes from two Thyr-IL-4 mouse lines (#30 and #52) expressed IL-4, which was secreted into the extracellular space. Although 10-month-old transgenic animals had T4 and thyrotropin serum levels in the normal range, they had altered thyroid follicular structure with enlarged follicles composed of elongated thyrocytes containing numerous endocytic vesicles. These follicles were positive for T4 staining the colloid, indicating their capacity to produce thyroid hormones. RNA profiling of Thyr-IL-4 thyroid samples revealed modulation of multiple genes involved in inflammation, while no major leukocyte infiltration could be detected. Upregulated expression of Duox1, Duoxa1, and the pendrin anion exchanger gene (Slc26a4) was detected. In contrast, the iodide symporter gene Slc5a5 was markedly

  8. Anharmonic Theoretical Vibrational Spectroscopy of Polypeptides.

    Science.gov (United States)

    Panek, Paweł T; Jacob, Christoph R

    2016-08-18

    Because of the size of polypeptides and proteins, the quantum-chemical prediction of their vibrational spectra presents an exceptionally challenging task. Here, we address one of these challenges, namely, the inclusion of anharmonicities. By performing the expansion of the potential energy surface in localized-mode coordinates instead of the normal-mode coordinates, it becomes possible to calculate anharmonic vibrational spectra of polypeptides efficiently and reliably. We apply this approach to calculate the infrared, Raman, and Raman optical activity spectra of helical alanine polypeptides consisting of up to 20 amino acids. We find that while anharmonicities do not alter the band shapes, simple scaling procedures cannot account for the different shifts found for the individual bands. This closes an important gap in theoretical vibrational spectroscopy by making it possible to quantify the anharmonic contributions and opens the door to a first-principles calculation of multidimensional vibrational spectra.

  9. Transport of free 211At and 125I- in thyroid epithelial cells: effects of anion channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid on apical efflux and cellular retention

    International Nuclear Information System (INIS)

    Lindencrona, Ulrika; Forssell-Aronsson, Eva; Nilsson, Mikael

    2007-01-01

    Introduction: Astatine ( 211 At; α-emitter; t 1/2 =7.21 h) shares several features with its halogen neighbour iodine. In the present study, we investigated whether 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) can be used to increase the cellular retention time of 211 At and radioiodide in thyroid epithelial cells. Methods: The transepithelial transport and cellular uptake of 211 At and 125 I - were studied simultaneously in porcine thyrocytes cultured in bicameral chambers. The cells were prestimulated with thyroid-stimulating hormone (TSH) or epidermal growth factor (EGF) for 48 h. In addition, the acute effects of DIDS and forskolin were investigated. Results: The transepithelial transport of both radionuclides was stimulated by TSH and down-regulated by EGF. DIDS rapidly reduced the efflux and increased the cellular content of 125 I - in control and TSH-stimulated cells, whereas DIDS had no effect on 125 I - transport in EGF-treated cells. DIDS blocked the 211 At efflux only in TSH-stimulated cells. Unexpectedly, DIDS caused an accelerated efflux of 211 At in both control and EGF-stimulated cells and, furthermore, reduced the cellular content of 211 At in the EGF-stimulated cultures. DIDS had no effect on the forskolin-induced efflux of the two radionuclides. Conclusions: The magnitude of thyroidal 211 At uptake and efflux is similar to that of 125 I - , strongly dependent on the functional activity of the cells. However, 211 At efflux likely involves several permeating mechanisms with different sensitivity to DIDS, which are at least partly not shared by 125 I - . The results suggest that anion channel blockage is potentially useful to increase the absorbed dose from both 211 At and radioiodine in NIS-expressing tumours

  10. Drug transporters in the lung--do they play a role in the biopharmaceutics of inhaled drugs?

    Science.gov (United States)

    Bosquillon, Cynthia

    2010-05-01

    The role of transporters in drug absorption, distribution and elimination processes as well as in drug-drug interactions is increasingly being recognised. Although the lungs express high levels of both efflux and uptake drug transporters, little is known of the implications for the biopharmaceutics of inhaled drugs. The current knowledge of the expression, localisation and functionality of drug transporters in the pulmonary tissue and the few studies that have looked at their impact on pulmonary drug absorption is extensively reviewed. The emphasis is on transporters most likely to affect the disposition of inhaled drugs: (1) the ATP-binding cassette (ABC) superfamily which includes the efflux pumps P-glycoprotein (P-gp), multidrug resistance associated proteins (MRPs), breast cancer resistance protein (BCRP) and (2) the solute-linked carrier (SLC and SLCO) superfamily to which belong the organic cation transporter (OCT) family, the peptide transporter (PEPT) family, the organic anion transporter (OAT) family and the organic anion transporting polypeptide (OATP) family. Whenever available, expression and localisation in the intact human tissue are compared with those in animal lungs and respiratory epithelial cell models in vitro. The influence of lung diseases or exogenous agents on transporter expression is also mentioned.

  11. Potentiometric anion selective sensors

    NARCIS (Netherlands)

    Antonisse, M.M.G.; Reinhoudt, David

    1999-01-01

    In comparison with selective receptors (and sensors) for cationic species, work on the selective complexation and detection of anions is of more recent date. There are three important components for a sensor, a transducer element, a membrane material that separates the transducer element and the

  12. GLYCOSYLATED YGHJ POLYPEPTIDES FROM ENTEROTOXIGENIC ESCHERICHIA COLI (ETEC)

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to glycosylated YghJ polypeptides from or derived from enterotoxigenic Escherichia coli (ETEC) that are immunogenic. In particular, the present invention relates to compositions or vaccines comprising the polypeptides and their application in immunization, vaccination...

  13. Polypeptide electrophoretic pattern of Matricaria chamomilla and ...

    African Journals Online (AJOL)

    In order to study the effects of salinity and Fe-deficiency on electrophoresis pattern of polypeptides in two chamomile genera (Matricaria chamomilla and Anthemis nobilis), a factorial experiment was conducted based on completely randomized block design with three replications, in 2010. The experimental factors were two ...

  14. Recombinant Supercharged Polypeptides Restore and Improve Biolubrication

    NARCIS (Netherlands)

    Veeregowda, Deepak H.; Kolbe, Anke; van der Mei, Henny C.; Busscher, Henk J.; Herrmann, Andreas; Sharma, Prashant K.

    2013-01-01

    Recombinant supercharged polypeptides (SUPs) with low cytotoxicity are developed and applied to rejuvenate the lubrication of naturally occurring salivary conditioning films (SCFs). SUPs with 72 positive charges adsorbed and rigidified the SCFs and recruited mucins to form a hydrated layer. These

  15. Tuning Ice Nucleation with Supercharged Polypeptides

    NARCIS (Netherlands)

    Yang, Huige; Ma, Chao; Li, Kaiyong; Liu, Kai; Loznik, Mark; Teeuwen, Rosalie; van Hest, Jan C. M.; Zhou, Xin; Herrmann, Andreas; Wang, Jianjun

    2016-01-01

    Supercharged unfolded polypeptides (SUPs) are exploited for controlling ice nucleation via tuning the nature of charge and charge density of SUPs. The results show that positively charged SUPs facilitate ice nucleation, while negatively charged ones suppress it. Moreover, the charge density of the

  16. Endogenous pancreatic polypeptide in different vascular beds

    DEFF Research Database (Denmark)

    Henriksen, J H; Schwartz, Tania; Bülow, J B

    1986-01-01

    The plasma concentration of pancreatic polypeptide (PP-like immunoreactivity) was measured in different vascular beds in order to determine regional kinetics of endogenous PP in fasting, supine subjects with normal or moderately decreased kidney function. Patients with kidney disease (n = 10) had...

  17. Sources, transport and reactivity of anionic and non-ionic surfactants in several aquatic ecosystems in SW Spain: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Lara-Martin, Pablo A. [Departamento de Quimica Fisica, Facultad de Ciencias del Mar y Ambientales, Universidad de Cadiz, Campus Rio San Pedro s/n, 11510 Puerto Real, Cadiz (Spain)], E-mail: pablo.lara@uca.es; Gomez-Parra, Abelardo; Gonzalez-Mazo, Eduardo [Departamento de Quimica Fisica, Facultad de Ciencias del Mar y Ambientales, Universidad de Cadiz, Campus Rio San Pedro s/n, 11510 Puerto Real, Cadiz (Spain)

    2008-11-15

    Presence, distribution and transport mechanisms of the four major synthetic surfactants -linear alkylbenzene sulfonates (LAS), alkyl ethoxysulfates (AES), nonylphenol ethoxylates (NPEOs) and alcohol ethoxylates (AEOs)- have been simultaneously studied in different aquatic ecosystems. Urban wastewater discharges and industrial activities were identified as the main sources for these compounds and their metabolites. LAS, AES and carboxylic metabolites remained in the dissolved form (87-99%). However, NPEOs and AEOs were mostly associated with particulate matter (65-86%), so their degradation in the water column was limited due to their lower bioavailability. It was also observed that sorption to the particulate phase was more intense for longer homologs/ethoxymers for all surfactants. With respect to surface sediments, AES levels were considerably below (<0.25 mg/kg) the values detected for LAS and NPEOs. Concentrations of AEOs, however, were occasionally higher (several tens of ppm) than those found for the rest of the target compounds in several sampling stations. - Occurrence and reactivity of the main synthetic surfactants in freshwater and marine systems are discussed.

  18. Polypeptides having xylanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj; Shaghasi, Tarana

    2017-06-20

    The present invention relates to polypeptides having xylanase activity, catalytic domains, and carbohydrate binding domains, and polynucleotides encoding the polypeptides, catalytic domains, and carbohydrate binding domains. The present invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides, catalytic domains, and carbohydrate binding domains.

  19. Polypeptides having endoglucanase activity and polynucleotides encoding same

    Science.gov (United States)

    Spodsberg, Nikolaj

    2016-02-23

    The present invention relates to isolated polypeptides having endoglucanase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  20. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Science.gov (United States)

    Schnorr, Kirk; Kramer, Randall

    2016-04-05

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  1. Polypeptides having beta-glucosidase activity and polynucleotides encoding same

    Science.gov (United States)

    Harris, Paul; Golightly, Elizabeth

    2007-07-17

    The present invention relates to isolated polypeptides having beta-glucosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  2. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Schnorr, Kirk; Kramer, Randall

    2017-08-08

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  3. Polypeptides having beta-xylosidase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Liu, Ye; Duan, Junxin; Tang, Lan; McBrayer, Brett

    2017-07-04

    The present invention relates to isolated polypeptides having beta-xylosidase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  4. Polypeptides having xylanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Lopez de Leon, Alfredo; Rey, Michael

    2017-09-26

    The present invention relates to isolated polypeptides having xylanase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  5. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ye; Tang, Lan; Duan, Junxin

    2017-02-07

    The present invention relates to isolated polypeptides having cellobiohydrolase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  6. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding the same

    Science.gov (United States)

    Duan, Junxin; Schnorr, Kirk Matthew; Wu, Wenping

    2013-11-19

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  7. Chimeric polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Science.gov (United States)

    Wogulis, Mark; Sweeney, Matthew; Heu, Tia

    2017-06-14

    The present invention relates to chimeric GH61 polypeptides having cellulolytic enhancing activity. The present invention also relates to polynucleotides encoding the chimeric GH61 polypeptides; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the chimeric GH61 polypeptides.

  8. Polypeptides having cellobiohydrolase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Stringer, Mary Ann; McBrayer, Brett

    2016-11-29

    The present invention relates to isolated polypeptides having cellobiohydrolase activity, catalytic domains, and cellulose binding domains and polynucleotides encoding the polypeptides, catalytic domains, and cellulose binding domains. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides, catalytic domains, or cellulose binding domains.

  9. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Lan; Liu, Ye; Duan, Junxin; Zhang, Yu; Joergensen, Christian; Kramer, Randall

    2016-11-29

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  10. Polypeptides having xylanase activity and polynucleotides encoding same

    Science.gov (United States)

    Tang, Lan; Liu, Ye; Duan, Junxin; Hanshu, Ding

    2012-10-30

    The present invention relates to isolated polypeptides having xylanase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  11. Polynucleotides encoding polypeptides having beta-glucosidase activity

    Science.gov (United States)

    Harris, Paul; Golightly, Elizabeth

    2010-03-02

    The present invention relates to isolated polypeptides having beta-glucosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  12. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Science.gov (United States)

    Maiyuran, Suchindra; Kramer, Randall; Harris, Paul

    2013-10-29

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  13. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Duan, Junxin; Tang, Lan; Wu, Wenping

    2016-11-22

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  14. Polypeptides having cellulolytic enhancing activity and nucleic acids encoding same

    Science.gov (United States)

    Brown, Kimberly; Harris, Paul; Zaretsky, Elizabeth; Re, Edward; Vlasenko, Elena; McFarland, Keith; Lopez de Leon, Alfredo

    2012-10-16

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  15. Polypeptides having xylanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Lopez de Leon, Alfredo; Rey, Michael

    2016-05-31

    The present invention relates to isolated polypeptides having xylanase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  16. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Duan, Junxin; Tang, Lan; Wu, Wenping

    2016-06-14

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  17. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Lan; Liu, Ye; Duan, Junxin; Wu, Wenping; Kramer, Randall

    2017-09-19

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  18. Polypeptides having endoglucanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Spodsberg, Nikolaj; Shagasi, Tarana

    2017-05-30

    The present invention relates to isolated polypeptides having endoglucanase activity, catalytic domains, cellulose binding domains and polynucleotides encoding the polypeptides, catalytic domains or cellulose binding domains. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides, catalytic domains or cellulose binding domains.

  19. Polypeptides having endoglucanase activity and polynucleotides encoding same

    Science.gov (United States)

    Harris, Paul; Lopez de Leon, Alfredo; Rey, Michael; Ding, Hanshu; Vlasenko, Elena

    2010-11-02

    The present invention relates to isolated polypeptides having endoglucanase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  20. Polypeptides having cellulolytic enhancing activity and nucleic acids encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Kimberly; Harris, Paul; Zaretsky, Elizabeth; Re, Edward; Vlasenko, Elena; McFarland, Keith; Lopez de Leon, Alfredo

    2016-08-09

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  1. Polypeptides having cellulolytic enhancing activity and nucleic acids encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Kimberly; Harris, Paul; Zaretsky, Elizabeth; Re, Edward; Vlasenko, Elena; McFarland, Keith; Lopez de Leon, Alfredo

    2017-09-05

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  2. Polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Schnorr, Kirk; Kramer, Randall

    2016-08-09

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  3. Polypeptides having xylanase activity and polynucleotides encoding the same

    Science.gov (United States)

    Spodsberg, Nikolaj [Bagsvaed, DK

    2014-01-07

    The present invention relates to isolated polypeptides having xylanase activity and isolated polynucleotides encoding the polypeptides. The inventino also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  4. Polypeptides having beta-glucosidase activity and polynucleotides encoding same

    Science.gov (United States)

    Morant, Marc Dominique

    2014-10-14

    The present invention relates to isolated polypeptides having beta-glucosidase activity, beta-xylosidase activity, or beta-glucosidase and beta-xylosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  5. Polypeptide from a cellulolytic fungus having cellulolytic enhancing activity

    Science.gov (United States)

    Brown, Kimberly [Elk Grove, CA; Harris, Paul [Carnation, WA; Zaretsky, Elizabeth [Reno, NV; Re, Edward [Davis, CA; Vlasenko, Elena [Davis, CA; McFarland, Keith [Davis, CA; Lopez de Leon, Alfredo [Davis, CA

    2008-04-22

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.

  6. Polypeptides having endoglucanase activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Liu, Ye; Duan, Junxin; Tang, Lan

    2018-01-30

    The present invention relates to isolated polypeptides having endoglucanase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  7. Expression and regulation of prostaglandin transporters, ATP-binding cassette, subfamily C, member 1 and 9, and solute carrier organic anion transporter family, member 2A1 and 5A1 in the uterine endometrium during the estrous cycle and pregnancy in pigs

    Directory of Open Access Journals (Sweden)

    Hwanhee Jang

    2017-05-01

    Full Text Available Objective Prostaglandins (PGs function in various reproductive processes, including luteolysis, maternal pregnancy recognition, conceptus development, and parturition. Our earlier study has shown that PG transporters ATP-binding cassette, subfamily C, member 4 (ABCC4 and solute carrier organic anion transporter family, member 2A1 (SLCO2A1 are expressed in the uterine endometrium in pigs. Since several other PG transporters such as ABCC1, ABCC9, SLCO4C1, and SLCO5A1 are known to be present in the uterine endometrium, this study investigated the expression of these PG transporters in the porcine uterine endometrium and placenta. Methods Uterine endometrial tissues were obtained from gilts on day (D 12 and D15 of the estrous cycle and days 12, 15, 30, 60, 90, and 114 of pregnancy. Results ABCC1, ABCC9, SLCO4C1, and SLCO5A1 mRNAs were expressed in the uterine endometrium, and levels of expression changed during the estrous cycle and pregnancy. Expression of ABCC1 and ABCC9 mRNAs was localized mainly to luminal and glandular epithelial cells in the uterine endometrium, and chorionic epithelial cells during pregnancy. Conceptuses during early pregnancy and chorioallantoic tissues from mid to late pregnancy also expressed these PG transporters. Estradiol-17β increased the expression of ABCC1 and SLCO5A1, but not ABCC9 and SLCO4C1 mRNAs and increasing doses of interleukin-1β induced the expression of ABCC9, SLCO4C1, and SLCO5A1 mRNAs in endometrial explant tissues. Conclusion These data showed that several PG transporters such as ABCC1, ABCC9, SLCO4C1, and SLCO5A1 were expressed at the maternal-conceptus interface, suggesting that these PG transporters may play an important role in the establishment and maintenance of pregnancy by regulating PG transport in the uterine endometrium and placenta in pigs.

  8. Primary and secondary thyroid hormone transporters

    Directory of Open Access Journals (Sweden)

    Kinne Anita

    2011-08-01

    Full Text Available Abstract Thyroid hormones (TH are essential for the development of the human brain, growth and cellular metabolism. Investigation of TH transporters became one of the emerging fields in thyroid research after the discovery of inactivating mutations in the Monocarboxylate transporter 8 (MCT8, which was found to be highly specific for TH transport. However, additional transmembrane transporters are also very important for TH uptake and efflux in different cell types. They transport TH as secondary substrates and include the aromatic amino acid transporting MCT10, the organic anion transporting polypeptides (e.g. OATP1C1, OATP1A2, OPTP1A4 and the large neutral amino acid transporters (LAT1 and LAT2. These TH transporters characteristically possess 12 transmembrane spanners but due to the strong differing sequences between the three transporter families we assume an identical conformation is not very likely. In contrast to the others, the LAT family members form a heterodimer with the escort protein 4F2hc/CD98. A comparison of sequence proportions, locations and types of functional sensitive features for TH transport discovered by mutations, revealed that transport sensitive charged residues occur as conserved amino acids only within each family of the transporter types but not in all putative TH transporters. Based on the lack of highly conserved sensitive charged residues throughout the three transporter families as a common counterpart for the amino acid moiety of the substrates, we conclude that the molecular transport mechanism is likely organized either a by different molecular determinants in the divergent transporter types or b the counterparts for the substrates` amino acid moiety at the transporter are not any charged side chains but other proton acceptors or donators. However, positions of transport sensitive residues coincide at transmembrane helix 8 in the TH transporter MCT8, OATP1C1 and another amino acid transporter, the L

  9. Measles virus polypeptides in purified virions and in infected cells

    International Nuclear Information System (INIS)

    Vainionpaeae, R.; Ziola, B.; Salmi, A.

    1978-01-01

    A wild-type measles virus was radiolabeled during growth in VERO cells and purified by two successive potassium tartrate gradient centrifugations. The virion polypeptide composition was determined by SDS-polyacrylamide gel electrophoresis employing two different buffer systems. Six virus-specific polypeptides were consistently detected. The largest (L) had a molecular weight (MW) of greater than 150,000. The second largest polypeptide, G (MW 79,000), was the only glycoprotein found. The proteins designated polypeptide 2 (MW 66 to 70,000) and nucleocapsid protein or NP (MW 61,000) were phosphorylated. The remaining virus-coded proteins were polypeptide 5 (MW 40,000) and the matrix or M protein (MW 37,000). Measles virions also contained a polypeptide (MW 42,000) thought to be actin due to co-migration with this component of uninfected cells. Analysis of in vitro 3 H-acetic anhydride radiolabeled virions confirmed the presence of these seven polypeptides. Acetic anhydride also labeled a protein designated polypeptide 4 (MW 53,000) which was not consistently radiolabeled in vivo, as well as several other minor proteins believed to be cellular in origin. Synthesis of the six virus-specific structural polypeptides was detected in lysates of infected cells by SDS-polyacrylamide slab gel electrophoresis. Virus specificity of polypeptide 4 could not be confirmed due to the similar MW of several cellular polypeptides. Two non-virion, but virus-specified polypeptides, of MW 38,000 and 18,000 were also detected. Synthesis of the virus structural proteins was in the same proportions as the polypeptides found in virions except for under production of polypeptide G and over production of polypeptide 2. (author)

  10. Secretion of organic anions by hepatocytes : Involvement of homologues of the multidrug resistance protein

    NARCIS (Netherlands)

    Muller, M; Roelofsen, H; Jansen, PLM

    The canalicular multispecific organic anion transporter (cMOAT) is one of at least four ATP-dependent transport systems identified so far in the canalicular membrane domain. Using mutant rat strains that lack organic anion secretion, the substrate specificity of cMOAT has been characterized. cMOAT

  11. POLYPEPTIDE AND POLYSACCHARIDE PROCESSING IN HYPERTHERMOPHILIC MICROORGANISMS

    Energy Technology Data Exchange (ETDEWEB)

    KELLY, ROBERT M.

    2008-12-22

    This project focused on the microbial physiology and biochemistry of heterotrophic hyperthermophiles with respect to mechanisms by which these organisms process polypeptides and polysaccharides under normal and stressed conditions. Emphasis is on two model organisms, for which completed genome sequences are available: Pyrococcus furiosus (growth Topt of 98°C), an archaeon, and Thermotoga maritima (growth Topt of 80°C), a bacterium. Both organisms are obligately anaerobic heterotrophs that reduce sulfur facultatively. Whole genome cDNA spotted microarrays were used to follow transcriptional response to a variety of environmental conditions in order to identify genes encoding proteins involved in the acquisition, synthesis, processing and utilization of polypeptides and polysaccharides. This project provided new insights into the physiological aspects of hyperthermophiles as these relate to microbial biochemistry and biological function in high temperature habitats. The capacity of these microorganisms to produce biohydrogen from renewable feedstocks makes them important for future efforts to develop biofuels.

  12. Nanostructured complexes of polyelectrolytes and charged polypeptides

    Czech Academy of Sciences Publication Activity Database

    Müller, M.; Ouyang, W.; Bohatá, Karolína; Kessler, B.

    2010-01-01

    Roč. 12, Sp. Iss. 9 (2010), B519-B528 ISSN 1438-1656. [Sino-German Symposium on Advanced Biomedical Nanostructures /1./. Jena, 26.10.2009-30.10.2009] Institutional research plan: CEZ:AV0Z40500505 Keywords : situ ATR-FTIR * alpha-helical polypeptides * multilayer films Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.746, year: 2010

  13. Improved docking of polypeptides with Glide.

    Science.gov (United States)

    Tubert-Brohman, Ivan; Sherman, Woody; Repasky, Matt; Beuming, Thijs

    2013-07-22

    Predicting the binding mode of flexible polypeptides to proteins is an important task that falls outside the domain of applicability of most small molecule and protein-protein docking tools. Here, we test the small molecule flexible ligand docking program Glide on a set of 19 non-α-helical peptides and systematically improve pose prediction accuracy by enhancing Glide sampling for flexible polypeptides. In addition, scoring of the poses was improved by post-processing with physics-based implicit solvent MM-GBSA calculations. Using the best RMSD among the top 10 scoring poses as a metric, the success rate (RMSD ≤ 2.0 Å for the interface backbone atoms) increased from 21% with default Glide SP settings to 58% with the enhanced peptide sampling and scoring protocol in the case of redocking to the native protein structure. This approaches the accuracy of the recently developed Rosetta FlexPepDock method (63% success for these 19 peptides) while being over 100 times faster. Cross-docking was performed for a subset of cases where an unbound receptor structure was available, and in that case, 40% of peptides were docked successfully. We analyze the results and find that the optimized polypeptide protocol is most accurate for extended peptides of limited size and number of formal charges, defining a domain of applicability for this approach.

  14. Polypeptide having carbohydrate degrading activity and uses thereof

    Science.gov (United States)

    Schooneveld-Bergmans, Margot Elisabeth Francoise; Heijne, Wilbert Herman Marie; Vlasie, Monica Diana; Damveld, Robbertus Antonius

    2015-08-18

    The invention relates to a polypeptide comprising the amino acid sequence set out in SEQ ID NO: 2 or an amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 1, or a variant polypeptide or variant polynucleotide thereof, wherein the variant polypeptide has at least 73% sequence identity with the sequence set out in SEQ ID NO: 2 or the variant polynucleotide encodes a polypeptide that has at least 73% sequence identity with the sequence set out in SEQ ID NO: 2. The invention features the full length coding sequence of the novel gene as well as the amino acid sequence of the full-length functional polypeptide and functional equivalents of the gene or the amino acid sequence. The invention also relates to methods for using the polypeptide in industrial processes. Also included in the invention are cells transformed with a polynucleotide according to the invention suitable for producing these proteins.

  15. Polypeptide having acetyl xylan esterase activity and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Schoonneveld-Bergmans, Margot Elisabeth Francoise; Heijne, Wilbert Herman Marie; Los, Alrik Pieter

    2015-10-20

    The invention relates to a polypeptide comprising the amino acid sequence set out in SEQ ID NO: 2 or an amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 1, or a variant polypeptide or variant polynucleotide thereof, wherein the variant polypeptide has at least 82% sequence identity with the sequence set out in SEQ ID NO: 2 or the variant polynucleotide encodes a polypeptide that has at least 82% sequence identity with the sequence set out in SEQ ID NO: 2. The invention features the full length coding sequence of the novel gene as well as the amino acid sequence of the full-length functional polypeptide and functional equivalents of the gene or the amino acid sequence. The invention also relates to methods for using the polypeptide in industrial processes. Also included in the invention are cells transformed with a polynucleotide according to the invention suitable for producing these proteins.

  16. Thermophilic and thermoacidophilic sugar transporter genes and enzymes from Alicyclobacillus acidocaldarius and related organisms, methods

    Science.gov (United States)

    Thompson, David N.; Apel, William A.; Thompson, Vicki S.; Reed, David W.; Lacey, Jeffrey A.

    2013-01-29

    Isolated and/or purified polypeptides and nucleic acid sequences encoding polypeptides from Alicyclobacillus acidocaldarius are provided. Further provided are methods for transporting sugars across cell membranes using isolated and/or purified polypeptides and nucleic acid sequences from Alicyclobacillus acidocaldarius.

  17. Ordered Nanostructures Made Using Chaperonin Polypeptides

    Science.gov (United States)

    Trent, Jonathan; McMillan, Robert; Paavola, Chad; Mogul, Rakesh; Kagawa, Hiromi

    2004-01-01

    A recently invented method of fabricating periodic or otherwise ordered nanostructures involves the use of chaperonin polypeptides. The method is intended to serve as a potentially superior and less expensive alternative to conventional lithographic methods for use in the patterning steps of the fabrication of diverse objects characterized by features of the order of nanometers. Typical examples of such objects include arrays of quantum dots that would serve as the functional building blocks of future advanced electronic and photonic devices. A chaperonin is a double-ring protein structure having a molecular weight of about 60 plus or minus 5 kilodaltons. In nature, chaperonins are ubiquitous, essential, subcellular structures. Each natural chaperonin molecule comprises 14, 16, or 18 protein subunits, arranged as two stacked rings approximately 16 to 18 nm tall by approximately 15 to 17 nm wide, the exact dimensions depending on the biological species in which it originates. The natural role of chaperonins is unknown, but they are believed to aid in the correct folding of other proteins, by enclosing unfolded proteins and preventing nonspecific aggregation during assembly. What makes chaperonins useful for the purpose of the present method is that under the proper conditions, chaperonin rings assemble themselves into higher-order structures. This method exploits such higher-order structures to define nanoscale devices. The higher-order structures are tailored partly by choice of chemical and physical conditions for assembly and partly by using chaperonins that have been mutated. The mutations are made by established biochemical techniques. The assembly of chaperonin polypeptides into such structures as rings, tubes, filaments, and sheets (two-dimensional crystals) can be regulated chemically. Rings, tubes, and filaments of some chaperonin polypeptides can, for example, function as nano vessels if they are able to absorb, retain, protect, and release gases or

  18. Phase transitions in polypeptides: analysis of energy fluctuations

    DEFF Research Database (Denmark)

    Yakubovich, Alexander V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2009-01-01

    The helix random coil transition in alanine, valine, and leucine polypeptides consisting of 30 amino acids is studied in vacuo using the Langevin molecular dynamics approach. The influence of side chain radicals on internal energy and heat capacity of the polypeptides is discussed. The heat...... capacity of these polypeptides is calculated as a function of temperature using two different methods, namely, as the derivative of the energy with respect to temperature, and on the basis of energy fluctuations in the system. The convergence of the fluctuations based approach is analyzed as a function...... of simulation time. This study provides a comparison of methods for the description of structural transitions in polypeptides....

  19. [New drug developments of snake venom polypeptides and progress].

    Science.gov (United States)

    Fu, Sihai; Feng, Mei; Xiong, Yan

    2017-11-28

    The value of snake venom polypeptides in clinical application has drawn extensive attention, and the development of snake polypeptides into new drugs with anti-tumor, anti-inflammatory, antithrombotic, analgesic or antihypertensive properties has become the recent research hotspot. With the rapid development of molecular biology and biotechnology, the mechanisms of snake venom polypeptides are also gradually clarified. Numerous studies have demonstrated that snake venom polypeptides exert their pharmacological effects by regulating ion channels, cell proliferation, apoptosis, intracellular signaling pathway, and expression of cytokine as well as binding to relevant active sites or receptors.

  20. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Unknown

    trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange properties together with surface basicity making them materials of importance ...

  1. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Together with hydrotalcite-like layered double hydroxides, bivalent and trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange ...

  2. Detection of Specific Polypeptide(s Synthesized during the Sequential Stages of Differentiation in Dioscorea species

    Directory of Open Access Journals (Sweden)

    Ashwani Kumar

    2015-10-01

    Full Text Available ABSTRACTThe present investigation was aimed to detect the specific polypeptide(s appeared during the sequential stages of differentiation. Among different explants, only nodal explants showed good results for callusing. Depending on the fresh and dry weight, best callus growth was observed on MS medium supplemented with NAA (2.5 mg/L inDioscorea alata and 2, 4-D (2.0 mg/L inD. deltoidea, respectively. This callus was used for the regeneration. Roots differentiation was observed on MS medium + NAA (2.0 mg/L + IBA (0.5 mg/L and shoots on MS medium + BAP (2.0 mg/L + NAA (0.5 mg/L in D. alata while in D. deltoidea, roots on RT medium + IAA (1.0 mg/L and shoots on RT medium + BAP (1.0 mg/L + NAA (0.5 mg/L. Continuous decrease was seen in the total soluble protein during the differentiation inD. alatawhereas inD. deltoidea, the protein content decreased upto initiation stage. Four root specific polypeptides (MW 25.56, 24.35, 19.13 and 18.2 kDa and three shoot specific polypeptides (MW 53.7, 25.12 and 19.13 kDa were synthesized during the differentiation inD. alata. Similarly, two root specific (MW 33.9 and 31.69 kDa and one shoot specific (MW 16.98 kDa polypeptide band were appeared during differentiation in D. deltoidea.

  3. Nuclear localization and function of polypeptide ligands and their receptors: a new paradigm for hormone specificity within the mammary gland?

    International Nuclear Information System (INIS)

    Clevenger, Charles V

    2003-01-01

    The specific effects triggered by polypeptide hormone/growth factor stimulation of mammary cells were considered mediated solely by receptor-associated signaling networks. A compelling body of new data, however, clearly indicates that polypeptide ligands and/or their receptors are transported into the nucleus, where they function directly to regulate the expression of specific transcription factors and gene loci. The intranuclear function of these complexes may contribute to the explicit functions associated with a given ligand, and may serve as new targets for pharmacologic intervention

  4. Membrane permeability in the gastrointestinal tract: the interplay between microclimate pH and transporters.

    Science.gov (United States)

    Kristl, Albin

    2009-11-01

    Some examples of pH- and transporter-dependent permeability, determined in side-by-side diffusion cells, are summarized. We investigated the polarized transport in the mucosal-to-serosal direction of monocarboxylic acid-type drugs through the excised rat jejunal tissue and an artificial membrane. We established that, in vitro, these substances are most probably not transported by monocarboxylate transporter 1, but by passive pH-dependent transport. We also studied various influences on the permeability of fluorescein, a low permeability marker, through isolated rat intestinal segments, Caco-2 cell monolayers, and an artificial membrane. Polarized transport of fluorescein in the serosal-to-mucosal direction through the rat jejunum by multidrug resistance-associated protein was triggered by the addition of D-glucose to the mucosal side, while the pH-dependent increase of fluorescein influx is presumably the consequence of a monocarboxylate transporter and a member of the organic-anion transporting polypeptide family. With permeability experiments through the excised segments of rat small intestine, we ascertained that ciprofloxacin is a low-permeability drug and has higher and pH-dependent transport in the mucosal-to-serosal direction than in the opposite direction. We also established that neither the permeability of fluoroquinolones nor their solubility in different buffers was influenced by the interactions with metal cations.

  5. A pH- and temperature-responsive bioresorbable injectable hydrogel based on polypeptide block copolymers for the sustained delivery of proteins in vivo.

    Science.gov (United States)

    Turabee, Md Hasan; Thambi, Thavasyappan; Duong, Huu Thuy Trang; Jeong, Ji Hoon; Lee, Doo Sung

    2018-02-27

    Sustained delivery of protein therapeutics is limited owing to the fragile nature of proteins. Despite its great potential, delivery of proteins without any loss of bioactivity remains a challenge in the use of protein therapeutics in the clinic. To surmount this shortcoming, we report a pH- and temperature-responsive in situ-forming injectable hydrogel based on comb-type polypeptide block copolymers for the controlled delivery of proteins. Polypeptide block copolymers, composed of hydrophilic polyethylene glycol (PEG), temperature-responsive poly(γ-benzyl-l-glutamate) (PBLG), and pH-responsive oligo(sulfamethazine) (OSM), exhibit pH- and temperature-induced sol-to-gel transition behavior in aqueous solutions. Polypeptide block copolymers were synthesized by combining N-carboxyanhydride-based ring-opening polymerization and post-functionalization of the chain-end using N-hydroxy succinimide ester activated OSM. The physical properties of polypeptide-based hydrogels were tuned by varying the composition of temperature- and pH-responsive PBLG and OSM in block copolymers. Polypeptide block copolymers were non-toxic to human embryonic kidney cells at high concentrations (2000 μg mL -1 ). Subcutaneous administration of polypeptide block copolymer sols formed viscoelastic gel instantly at the back of Sprague-Dawley (SD) rats. The in vivo gels exhibited sustained degradation and were found to be bioresorbable in 6 weeks without any noticeable inflammation at the injection site. Anionic characteristics of hydrogels allow efficient loading of a cationic model protein, lysozyme, through electrostatic interaction. Lysozyme-loaded polypeptide block copolymer sols readily formed a viscoelastic gel in vivo and sustained lysozyme release for at least a week. Overall, the results demonstrate an elegant approach to control the release of certain charged proteins and open a myriad of therapeutic possibilities in protein therapeutics.

  6. In vitro and in vivo phosphorylation of polypeptides in plasma membrane and tonoplast-enriched fractions from barley roots

    International Nuclear Information System (INIS)

    Garbarino, J.E.; Hurkman, W.J.; Tanaka, C.K.; DuPont, F.M.

    1991-01-01

    Phosphorylation of polypeptides in membrane fractions from barley (Hordeum vulgare L. cv CM 72) roots was compared in in vitro and in vivo assays to assess the potential role of protein kinases in modification of membrane transport. Membrane fractions enriched in endoplasmic reticulum, tonoplast, and plasma membrane were isolated using sucrose gradients and the membrane polypeptides separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis. When the membrane fractions were incubated with γ[p 32 P]ATP, phosphorylation occurred almost exclusively in the plasma membrane fraction. Phosphorylation of a band at 38 kilodaltons increased as the concentration of Mg 2+ was decreased from millimolar to micromolar levels. Phosphorylation of bands at 125, 86, 58, 46 and 28 kilodaltons required millimolar Mg 2+ concentrations and was greatly enhanced by Ca 2+ . When roots of intact plants were labeled with [ 32 P]orthophosphate, polypeptides at approximately 135, 166, 90, 46 to 53, 32, 28, and 19 kilodaltons were labeled in the plasma membrane fraction and polypeptides at approximately 73, 66, and 48 kilodaltons were labeled in the tonoplast fraction. Treatment of the roots of intact plants with 150 millimolar NaCl resulted in increased phosphorylation of some polypeptides while treatment with 100 mM NaCl had no effect

  7. Interplay between Folding and Assembly of Fibril-Forming Polypeptides

    NARCIS (Netherlands)

    Ni, R.; Abeln, S.; Schor, M.; Cohen Stuart, M.A.; Bolhuis, P.G.

    2013-01-01

    Polypeptides can self-assemble into hierarchically organized fibrils consisting of a stack of individually folded polypeptides driven together by hydrophobic interaction. Using a coarse-grained model, we systematically studied this self-assembly as a function of temperature and hydrophobicity of the

  8. Enzyme-catalyzed synthesis of polyamides and polypeptides

    Science.gov (United States)

    Polyamides and polypeptides are important polymers in biological systems and industrial processes. Usually polyamides are produced via chemical synthesis, whereas polypeptides and proteins are isolated from living systems or produced from Merrifield synthesis. An area of active research is to use ...

  9. Measles virus-specified polypeptides in infected cells

    International Nuclear Information System (INIS)

    Vainionpaepae, R.

    1979-01-01

    The synthesis of wild-type measles virus-specified polypeptides in Vero cells in pulse-chase experiments, in cells with synchronized protein synthesis by high salt concentration, and in the presence of proteolytic enzyme inhibitors was analyzed by polyacrylamide slab-gel electrophoresis. Six major (L, G, 2, NP, 5 and M) structural polypeptides were identified in infected cells. The results of pulse-chase experiments suggested that most of the structural polypeptides were synthesized at their final length. Polypeptide M was found to be sensitive to trypsin. In TLCK-treated cells its molecular weight was about 1000-2000 daltons higher than in untreated cells. A minor virus-specific polypeptide with a molecular weight of about 23,000 was found as a very faint and diffuse band. In addition, three nonstructural polypeptides with molecular weights of 65,000, 38,000 and 18,000 were also detected. The experiments with proteolytic enzyme inhibitors and with synchronized protein synthesis suggested that the polypeptide with a molecular weight of 65,000 might be a precursor of the structural polypeptide 5. (author)

  10. Chirality-selected phase behaviour in ionic polypeptide complexes

    Science.gov (United States)

    Perry, Sarah L.; Leon, Lorraine; Hoffmann, Kyle Q.; Kade, Matthew J.; Priftis, Dimitrios; Black, Katie A.; Wong, Derek; Klein, Ryan A.; Pierce, Charles F.; Margossian, Khatcher O.; Whitmer, Jonathan K.; Qin, Jian; de Pablo, Juan J.; Tirrell, Matthew

    2015-01-01

    Polyelectrolyte complexes present new opportunities for self-assembled soft matter. Factors determining whether the phase of the complex is solid or liquid remain unclear. Ionic polypeptides enable examination of the effects of stereochemistry on complex formation. Here we demonstrate that chirality determines the state of polyelectrolyte complexes, formed from mixing dilute solutions of oppositely charged polypeptides, via a combination of electrostatic and hydrogen-bonding interactions. Fluid complexes occur when at least one of the polypeptides in the mixture is racemic, which disrupts backbone hydrogen-bonding networks. Pairs of purely chiral polypeptides, of any sense, form compact, fibrillar solids with a β-sheet structure. Analogous behaviour occurs in micelles formed from polypeptide block copolymers with polyethylene oxide, where assembly into aggregates with either solid or fluid cores, and eventually into ordered phases at high concentrations, is possible. Chirality is an exploitable tool for manipulating material properties in polyelectrolyte complexation. PMID:25586861

  11. Phosphazene-promoted anionic polymerization

    KAUST Repository

    Zhao, Junpeng

    2014-01-01

    In the recent surge of metal-free polymerization techniques, phosphazene bases have shown their remarkable potential as organic promoters/catalysts for the anionic polymerization of various types of monomers. By complexation with the counterion (e.g. proton or lithium cation), phosphazene base significantly improve the nucleophilicity of the initiator/chain-end resulting in rapid and usually controlled anionic/quasi-anionic polymerization. In this review, we will introduce the general mechanism, i.e. in situ activation (of initiating sites) and polymerization, and summarize the applications of such a mechanism on macromolecular engineering toward functionalized polymers, block copolymers and complex macromolecular architectures.

  12. Fibrillar dimer formation of islet amyloid polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Chi-cheng [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); de Pablo, Juan J. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-05-08

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 – 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 – 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  13. Fibrillar dimer formation of islet amyloid polypeptides

    Science.gov (United States)

    Chiu, Chi-cheng; de Pablo, Juan J.

    2015-09-01

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 - 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 - 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  14. Protein Encapsulation via Polypeptide Complex Coacervation

    Energy Technology Data Exchange (ETDEWEB)

    Black, Katie A.; Priftis, Dimitrios; Perry, Sarah L.; Yip, Jeremy; Byun, William Y.; Tirrell, Matthew

    2014-10-21

    Proteins have gained increasing success as therapeutic agents; however, challenges exist in effective and efficient delivery. In this work, we present a simple and versatile method for encapsulating proteins via complex coacervation with oppositely charged polypeptides, poly(L-lysine) (PLys) and poly(D/L-glutamic acid) (PGlu). A model protein system, bovine serum albumin (BSA), was incorporated efficiently into coacervate droplets via electrostatic interaction up to a maximum loading of one BSA per PLys/PGlu pair and could be released under conditions of decreasing pH. Additionally, encapsulation within complex coacervates did not alter the secondary structure of the protein. Lastly the complex coacervate system was shown to be biocompatible and interact well with cells in vitro. A simple, modular system for encapsulation such as the one presented here may be useful in a range of drug delivery applications.

  15. Pentaarylfullerenes as noncoordinating cyclopentadienyl anions

    NARCIS (Netherlands)

    Bouwkamp, Marco W.; Meetsma, Auke

    2009-01-01

    The first example of an early-transition-metal complex involving a pentaarylfullerene was prepared. Instead of half-sandwich complexes, solvent separated ion pairs were obtained in which the pentaarylfullerene moiety acts as noncoordinating cyclopentadienyl anion.

  16. Transportation

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Here is the decree of the thirtieth of July 1998 relative to road transportation, to trade and brokerage of wastes. It requires to firms which carry out a road transportation as well as to traders and to brokers of wastes to declare their operations to the prefect. The declaration has to be renewed every five years. (O.M.)

  17. Modeling Donnan Dialysis Separation for Carboxylic Anion Recovery

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Møllerhøj, Martin; Jørgensen, Sten Bay

    2010-01-01

    dynamic model for transport of multiple ions through an anion exchange membrane is derived based on an irreversible thermodynamics approach. This model accounts for the convective transport of the dissociated and undissociated species in the channels with diffusion and migration across the boundary...... layers and membranes. Donnan equilibrium, flux continuity of the transported ions, the electroneutrality condition and Faraday's law are employed to describe the electrical potential and concentration discontinuities at the interfaces. The Nernst-Planck equation is used to model the ion transport though...

  18. Bound anionic states of adenine

    Energy Technology Data Exchange (ETDEWEB)

    Haranczyk, Maciej; Gutowski, Maciej S; Li, Xiang; Bowen, Kit H

    2007-03-20

    Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases, are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine, which result from enamine-imine transformations, support valence anionic states with electron vertical detachment energies as large as 2.2 eV, and at least one of these anionic tautomers is adiabatically bound. Moreover, we predict that the new anionic tautomers should also dominate in solutions and should be characterized by larger values of electron vertical detachment energy than the canonical valence anion. All of the new-found anionic tautomers might be formed in the course of dissociative electron attachment followed by a hydrogen atom attachment to a carbon atom, and they might affect the structure and properties of DNA and RNA exposed to low-energy electrons. The discovery of these valence anionic states of adenine was facilitated by the development of: (i) a new experimental method for preparing parent anions of nucleic acid bases for photoelectron experiments, and (ii) a new combinatorial/ quantum chemical approach for identification of the most stable tautomers of organic molecules. The computational portion of this work was supported by the: (i) Polish State Committee for Scientific Research (KBN) Grants: DS/8000-4-0140-7 (M.G.) and N204 127 31/2963 (M.H.), (ii) European Social Funds (EFS) ZPORR/2.22/II/2.6/ARP/U/2/05 (M.H.), and (iii) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G.). M.H. holds the Foundation for Polish Science (FNP) award for young scientists. The calculations were performed at the Academic

  19. Principles Governing the Self Assembly of Polypeptide Nanoparticles

    Science.gov (United States)

    Wahome, Newton

    Self assembling systems on the nanometer scale afford the advantage of being able to control submicron level events. In this study, we focus on the self-assembling polypeptide nanoparticles (SAPN). The SAPN scaffold is made up of oligomerizing domains that align along the principle rotational axes of icosahedral symmetry. By aligning them along these axes, a particle with spherical geometry can be achieved. This particle can be utilized as a vaccine, as a drug delivery vehicle, or as a biomedical imaging device. This research will try to answer why the SAPN self-assembles into distinct molecular weight ranges while mostly maintaining a spherical morphology. The first means will be theoretical and computational, where we will utilize a mathematical formalism to find out how the packing of SAPN's monomeric units can occur within symmetric space. Then molecular dynamics will be run within this symmetric space to test the per amino acid residue susceptibility of SAPN towards becoming polymorphic in nature. Means for examining the aggregation propensity of SAPN will be also be tested. Specifically, the relationship of different sequences of SAPN with pH will be elucidated. Co-assembly of SAPN to reduce the surface density of an aggregation prone epitope will be tested. Also, aggregation reduction consisting of the exchange of an anionic denaturant with a positively charged suppressor in order to mitigate a priori peptide association and misfolding, will also be attempted. SAPN has been shown to be an immunogenic platform for the presentation of pathogen derived antigens. We will attempt to show the efficacy of presenting an antigen from HIV-1 which is structurally restrained to best match the native conformation on the virus. Immunological studies will be performed to test the effect of this approach, as well testing the antigenicity of the nanoparticle in the absence of adjuvant. Finally, the antigen presenting nanoparticles will undergo formulation testing, to measure

  20. Transportation

    National Research Council Canada - National Science Library

    Allshouse, Michael; Armstrong, Frederick Henry; Burns, Stephen; Courts, Michael; Denn, Douglas; Fortunato, Paul; Gettings, Daniel; Hansen, David; Hoffman, Douglas; Jones, Robert

    2007-01-01

    .... The ability of the global transportation industry to rapidly move passengers and products from one corner of the globe to another continues to amaze even those wise to the dynamics of such operations...

  1. Cancer Nano technology Using Elastin-Like Polypeptides

    International Nuclear Information System (INIS)

    Siti Najila Mohd Janib

    2014-01-01

    Despite progress in understanding cancer biology, this knowledge has not translated into comparable advances in the clinic. Two fundamental problems currently stalling the efficient treatment of cancer have been detecting cancer early enough for successful treatment and avoiding excessive toxicity to normal tissues. In view of this, cancer still remains one of the leading causes of mortality worldwide, affecting over 10 million new patients every year. Clearly the development of novel approaches for early detection and treatment of cancer is urgently needed to increase patient survival. Recently, nano technology-based systems have emerged as novel therapeutic modalities for cancer treatment. Tiny man made nanoparticles, much smaller than a virus, are being developed to package, transport, and deliver imaging and therapeutic agents. Co-inclusion of these agents, into nano carriers might be advantageous because they increase solubility of hydrophobic drugs, enhance permeability across physiological barriers, alter drug biodistribution, increase local bioavailability and reduce side effects. Initial findings have been promising and nanoparticles have been shown to deliver therapeutic agents to target cells and effect tumor growth. To this end our lab is investigating a class of biodegradable and biocompatible polymers known as elastin-like polypeptides (ELP). Elastin like polypeptide is a bio polymer derived from the structural motif found in mammalian elastin protein and has a sequence dependent transition temperature that can be used as nano carriers to treat diseases. ELPs are characterized by the pentameric repeat VPGXG, where X can be any amino acid. All functional ELPs undergo inverse phase transition whereby below its transition temperature, they exist in a solubilized form while above its transition temperature they undergo phase separation which leads to their aggregation in solution. This process is reversible. Phase transition can also be triggered by other

  2. Selective posttranslational modification of phage-displayed polypeptides

    Science.gov (United States)

    Tsao, Meng-Lin; Tian, Feng; Schultz, Peter

    2013-02-05

    The invention relates to posttranslational modification of phage-displayed polypeptides. These displayed polypeptides comprise at least one unnatural amino acid, e.g., an aryl-azide amino acid such as p-azido-L-phenylalanine, or an alkynyl-amino acid such as para-propargyloxyphenylalanine, which are incorporated into the phage-displayed fusion polypeptide at a selected position by using an in vivo orthogonal translation system comprising a suitable orthogonal aminoacyl-tRNA synthetase and a suitable orthogonal tRNA species. These unnatural amino acids advantageously provide targets for posttranslational modifications such as azide-alkyne [3+2]cycloaddition reactions and Staudinger modifications.

  3. Similarities in the induction of synthesis of a cell-surface polypeptide in Arthrobacter sp. by near-UV irradiation and photodynamic conditions

    International Nuclear Information System (INIS)

    Hoober, J.K.; Franzi, J.

    1983-01-01

    Irradiation of aerobic suspensions of Arthrobacter sp. with near-UV light (310-400 nm) induced synthesis of a 21 000 dalton, cell-surface polypeptide. Synthesis of this polypeptide also was induced by visible light in the presence of photodynamic dyes. Induction of the polypeptide in ear-UV light and with visible light plus dyes was inhibited by histidine. Hemin inhibited induction in near-UV light and in visible light with methylene blue, neutral red and acriflavin, which are cationic dyes, but failed to inhibit induction in visible light with rose bengal, an anionic dye. These results suggested that inhibition by hemin required electrostatically favored interaction between the anionic porphyrin and the sensitizer, and that the near-UV light effect was mediated by a cationic or neutral endogenous sensitizer. The similarities in the responses of the cells to near-UV irradiation and visible light plus dyes suggested that the mechanism of induction under the two conditions was the same. (author)

  4. Induction of a M/sub r/ 21,000 polypeptide in an Arthrobacter Sp. by dye-sensitized photooxidation

    International Nuclear Information System (INIS)

    Franzi, J.J.

    1985-01-01

    Irradiation of aerobic cultures of an Arthrobacter species with near-UV light and oxygen induced synthesis of a cell surface protein, M/sub r/ 21,000 polypeptide. Visible light, oxygen and a sensitizing dye were also effective in induction. Far-UV light, bleomycin and nalidixic acid, all inducers of the recA protein in Escherichia coli, were ineffective inducers of this protein. Furthermore, X-irradiation and radical-generating oxidants failed to induce synthesis of the M/sub r/ 21,000 polypeptide. DNA binding dyes proved to be capable of inducing synthesis of this protein or inhibiting dye-mediated stimulation of synthesis of this protein. For example, dGdC-specific dyes (e.g. methylene blue, neutral red, acridine orange or ethidium bromide) were efficient inducers of the M/sub r/ 21,000 polypeptide. Also methylene blue and neutral red were more efficient inducers than were acridine orange or ethidium bromide, which could be explained by the greater dGdC specificity and, possibly by the greater photoreactivity of methylene blue and neutral red. dAdT-specific dyes such as methyl green or daunomycin effectively inhibited dye-mediated induction. Rose bengal is an anionic dye which does not bind to DNA but does mediate the photooxidation of deoxyguanosine residues in DNA. It is an efficient inducer of the M/sub r/ 21,000 polypeptide. Induction with this dye is nearly eliminated when novobiocin, an inhibitor of DNA gyrase (topoisomerase II) which mediates relaxation, is added in conjunction with rose bengal

  5. Induction of a M/sub r/ 21,000 polypeptide in an Arthrobacter Sp. by dye-sensitized photooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Franzi, J.J.

    1985-01-01

    Irradiation of aerobic cultures of an Arthrobacter species with near-UV light and oxygen induced synthesis of a cell surface protein, M/sub r/ 21,000 polypeptide. Visible light, oxygen and a sensitizing dye were also effective in induction. Far-UV light, bleomycin and nalidixic acid, all inducers of the recA protein in Escherichia coli, were ineffective inducers of this protein. Furthermore, X-irradiation and radical-generating oxidants failed to induce synthesis of the M/sub r/ 21,000 polypeptide. DNA binding dyes proved to be capable of inducing synthesis of this protein or inhibiting dye-mediated stimulation of synthesis of this protein. For example, dGdC-specific dyes (e.g. methylene blue, neutral red, acridine orange or ethidium bromide) were efficient inducers of the M/sub r/ 21,000 polypeptide. Also methylene blue and neutral red were more efficient inducers than were acridine orange or ethidium bromide, which could be explained by the greater dGdC specificity and, possibly by the greater photoreactivity of methylene blue and neutral red. dAdT-specific dyes such as methyl green or daunomycin effectively inhibited dye-mediated induction. Rose bengal is an anionic dye which does not bind to DNA but does mediate the photooxidation of deoxyguanosine residues in DNA. It is an efficient inducer of the M/sub r/ 21,000 polypeptide. Induction with this dye is nearly eliminated when novobiocin, an inhibitor of DNA gyrase (topoisomerase II) which mediates relaxation, is added in conjunction with rose bengal.

  6. Effect of proquinazid and copper hydroxide on homeostasis of anions in winter wheat plants in generative phase of development

    Directory of Open Access Journals (Sweden)

    M. E. Riazanova

    2015-03-01

    nitrate form occur in the period of maximum activity of plants during grain maturation, that is why the increase of free nitrates concentration in all trial series may indicate the remobilization of nitrogen from vegetative organs to caryopsis. Analysis of wheat ear of the 1st trial shows increase in concentrations of free nitrates and phosphates in all trial series which may be explained by intensification of metabolic processes that occur in the ear during grain maturation. Comparison of results of 1st and 2nd trials shows the decrease of Cl concentration in plants of the 2nd trial which can be associated with extension of photosynthetic activity of leaves and participation of element in oxidative phosphorylation, as well as its binding with polypeptides belonging to photolysis complex of water of photosystem II. Thus, application of proquinazid and copper hydroxide at tillering stage increases the productive tillering capacity and enhances the pools of N, P, S free anions in winter wheat plants. These changes can be explained by the effect of fungicides on plant metabolic processes associated with remobilization and transport of elements from flag leaves to the ears during grain maturation. Autumn application of fungicides provides an excellent protection level against powdery mildew of winter wheat plants and creates optimal conditions for plants’ development and wintering. Treatment of plants in spring is highly effective against powdery mildew at tillering-booting stage.

  7. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Rehana Akter

    2016-01-01

    Full Text Available The hormone islet amyloid polypeptide (IAPP, or amylin plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.

  8. Biomedical applications of polypeptide multilayer nanofilms and microcapsules

    Science.gov (United States)

    Rudra, Jai Simha S.

    The past few years have witnessed considerable growth in synthetic polymer chemistry and physics, biomaterials science, and nano-scale engineering. Research on polypeptide multilayer films, coatings, and microcapsules is located at the intersection of these areas and are promising materials for applications in medicine, biotechnology, environmental science. Most envisioned applications of polypeptide multilayers have a biomedical bent. This dissertation on polypeptide multilayer film applications covers key points of polypeptides as materials, means of polymer production, film preparation, film characterization methods, and key points of current research in basic science. Both commercial and designed peptides have been used to fabricate films for in-vitro applications such as antimicrobial coatings and cell culture coatings and also microcapsules for drug delivery applications. Other areas of product development include artificial red blood cells, anisotropic coatings, enantioselective membranes, and artificial viruses.

  9. Controlling assembly of helical polypeptides via PEGylation strategies†

    Science.gov (United States)

    Top, Ayben; Zhong, Sheng; Yan, Congqi

    2013-01-01

    Recent studies in our laboratories have demonstrated that a helical polypeptide (17H6), equipped with a histidine tag and a helical alanine-rich, glutamic-acid-containing domain, exhibits pH-responsive assembly behavior useful in the production of polymorphological nanostructures. In this study, the histidine tag in these polypeptides was replaced by polyethylene glycol (PEG) with different molecular masses (5 kDa, or 10 kDa), and the self-association behavior of 17H6 and the PEGylated conjugates was characterized via dynamic light scattering (DLS), small angle neutron scattering (SANS), and cryogenic transmission electron microscopy (cryo-TEM). DLS experiments illustrated that the polypeptide and its PEG-conjugates undergo reversible assembly under acidic conditions, suggesting that the aggregation state of the polypeptide and the conjugates is controlled by the charged state of the glutamic acid residues. Nanoscale aggregates were detected at polypeptide/conjugate concentrations as low as 20 μM (∼0.3–0.5 mg ml−1) at physiological and ambient temperatures. Scattering and microscopy results showed that the size, the aggregation number, and the morphology of the aggregates can be tuned by the size and the nature of the hydrophilic tag. This tunable nature of the morphology of the aggregates, along with their low critical aggregation concentration, suggests that PEG-alanine-rich polypeptide conjugates may be useful as drug delivery vehicles in which the alanine-rich block serves as a drug attachment domain. PMID:24039625

  10. Biosynthesis of the neural cell adhesion molecule: characterization of polypeptide C

    DEFF Research Database (Denmark)

    Nybroe, O; Albrechtsen, M; Dahlin, J

    1985-01-01

    The biosynthesis of the neural cell adhesion molecule (N-CAM) was studied in primary cultures of rat cerebral glial cells, cerebellar granule neurons, and skeletal muscle cells. The three cell types produced different N-CAM polypeptide patterns. Glial cells synthesized a 135,000 Mr polypeptide B...... and a 115,000 Mr polypeptide C, whereas neurons expressed a 200,000 Mr polypeptide A as well as polypeptide B. Skeletal muscle cells produced polypeptide B. The polypeptides synthesized by the three cell types were immunochemically identical. The membrane association of polypeptide C was investigated...... with methods that distinguish peripheral and integral membrane proteins. Polypeptide C was found to be a peripheral membrane protein, whereas polypeptides A and B were integral membrane proteins with cytoplasmic domains of approximately 50,000 and approximately 25,000 Mr, respectively. The affinity...

  11. Mapping of polypeptides encoded by the Epstein-Barr virus genome in productive infection.

    OpenAIRE

    Hummel, M; Kieff, E

    1982-01-01

    Over 30 viral-specified polypeptides are translated in vitro from RNA of cells productively infected with Epstein-Barr virus (EBV). The polypeptides map to sites in EBV DNA by hybrid selection. Almost all of the polypeptides are reactive with EBV immune human serum. Several of the polypeptides are part of the early antigen complex. Two others are likely to be major structural components of the virus. Genes encoding persistent early and late polypeptides are intermixed through most of the EBV ...

  12. The effect of chronic renal failure on drug metabolism and transport.

    Science.gov (United States)

    Dreisbach, Albert W; Lertora, Juan J L

    2008-08-01

    Chronic renal failure (CRF) has been shown to significantly reduce the nonrenal clearance and alter bioavailability of drugs predominantly metabolized by the liver and intestine. The purpose of this article is to review all significant animal and clinical studies dealing with the effect of CRF on drug metabolism and transport. A search of the National Library of Medicine PubMed was done with terms such as chronic renal failure, cytochrome P450 [CYP], liver metabolism, efflux drug transport and uptake transport, including relevant articles back to 1969. Animal studies in CRF have shown a significant downregulation (40-85%) of hepatic and intestinal CYP metabolism. High levels of parathyroid hormone, cytokines and uremic toxins have been shown to reduce CYP activity. Phase II reactions and drug transporters such as P-glycoprotein and organic anion transporting polypeptide are also affected. CRF alters intestinal, renal and hepatic drug metabolism and transport producing a clinically significant impact on drug disposition and increasing the risk for adverse drug reactions.

  13. Pollen Tube Growth Regulation by Free Anions Depends on the Interaction between the Anion Channel SLAH3 and Calcium-Dependent Protein Kinases CPK2 and CPK20.

    NARCIS (Netherlands)

    Gutermuth, T.; Lassig, R.; Portes, M.T.; Maierhofer, T.; Romeis, T.; Borst, J.W.; Hedrich, R.; Feijó, J.A.; Konrad, K.R.

    2013-01-01

    Apical growth in pollen tubes (PTs) is associated with the presence of tip-focused ion gradients and fluxes, implying polar localization or regulation of the underlying transporters. The molecular identity and regulation of anion transporters in PTs is unknown. Here we report a negative gradient of

  14. Calcium-tolerant anionic surfactants

    NARCIS (Netherlands)

    Kooreman, Alexander

    1995-01-01

    One of the problems of applying anionic surfactants in, for example, laundry detergents is the precipitation of calcium salts. Much effort has been directed towards avoiding precipitation. There are at least three ways for tackling the problem. The first involves the use of a large quantity of

  15. Quantum mechanics of toroidal anions

    International Nuclear Information System (INIS)

    Afanas'ev, G.N.

    1990-01-01

    We consider a toroidal solenoid with an electric charge attached to it. It turns out that statistical properties of the wave function describing interacting toroidal anions depend on both their relative position and orientation. The influence of the particular gauge choice on the exchange properties of the wave function is studied. 30 refs.; 6 figs

  16. Surface active complexes formed between keratin polypeptides and ionic surfactants.

    Science.gov (United States)

    Pan, Fang; Lu, Zhiming; Tucker, Ian; Hosking, Sarah; Petkov, Jordan; Lu, Jian R

    2016-12-15

    Keratins are a group of important proteins in skin and hair and as biomaterials they can provide desirable properties such as strength, biocompatibility, and moisture regaining and retaining. The aim of this work is to develop water-soluble keratin polypeptides from sheep wool and then explore how their surface adsorption behaves with and without surfactants. Successful preparation of keratin samples was demonstrated by identification of the key components from gel electrophoresis and the reproducible production of gram scale samples with and without SDS (sodium dodecylsulphate) during wool fibre dissolution. SDS micelles could reduce the formation of disulphide bonds between keratins during extraction, reducing inter-molecular crosslinking and improving keratin polypeptide solubility. However, Zeta potential measurements of the two polypeptide batches demonstrated almost identical pH dependent surface charge distributions with isoelectric points around pH 3.5, showing complete removal of SDS during purification by dialysis. In spite of different solubility from the two batches of keratin samples prepared, very similar adsorption and aggregation behavior was revealed from surface tension measurements and dynamic light scattering. Mixing of keratin polypeptides with SDS and C 12 TAB (dodecyltrimethylammonium bromide) led to the formation of keratin-surfactant complexes that were substantially more effective at reducing surface tension than the polypeptides alone, showing great promise in the delivery of keratin polypeptides via the surface active complexes. Neutron reflection measurements revealed the coexistence of surfactant and keratin polypeptides at the interface, thus providing the structural support to the observed surface tension changes associated with the formation of the surface active complexes. Copyright © 2016. Published by Elsevier Inc.

  17. Methods and systems for measuring anions

    KAUST Repository

    Masih, Dilshad

    2016-08-18

    Embodiments of the present disclosure provide for methods for detecting the presence and/or concentration of anions in a solution, systems for detecting the presence and/or concentration of anions in a solution, anion sensor systems, and the like.

  18. Further investigations on the polypeptides and reconstitution of prasinophycean ejectisomes.

    Science.gov (United States)

    Ammermann, Silke; Hillebrand, Helmut; Rhiel, Erhard

    2014-06-01

    Ejectisome fragments were isolated from the prasinophyte Pyramimonas grossii and subjected to different treatments, i.e. Percoll density gradient centrifugation, incubation at pH 2.5 or at pH 10.8, or incubation in 6M guanidine hydrochloride. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that Percoll density gradient centrifugation did not improve the purity of the ejectisome fragment-enriched fractions. The ejectisome fragments withstood pH 2.5 and pH 10.8 treatment, and no loosely bound polypeptides became detached. The disintegration of ejectisome fragments was achieved in 6M guanidine hydrochloride, and reassembly into filamentous, ejectisome-like structures occurred after dialysis against distilled water. Fractions enriched either in ejectisome fragments or in reconstituted ejectisome-like structures were dominated by three polypeptides with relative molecular weights of approximately 12.5-19kDa and two additional polypeptides of 23 and 26kDa. A polyclonal antiserum directed against an ejectisome fragment-enriched fraction weakly cross-reacted with these polypeptides, and no significant immuno-labelling of ejectisome fragments was registered. A positive immuno-label was achieved using immunoglobulin (IgG) fractions which were gained by selectively incubating nitrocellulose stripes of these polypeptides with the antiserum. Copyright © 2014 Elsevier GmbH. All rights reserved.

  19. The anion-binding polyanion: a molecular cobalt vanadium oxide with anion-sensitive visual response.

    Science.gov (United States)

    Seliverstov, Andrey; Forster, Johannes; Heiland, Magdalena; Unfried, Johannes; Streb, Carsten

    2014-07-25

    An anionic molecular cobalt vanadium oxide cluster, (n-Bu4N)3[Co(AcO)V4O12] and its use as anion binding site is reported. Cluster formation is controlled by an anion-dependent dynamic solution equilibrium. Reversible anion binding in solution leads to significant spectral changes, allowing the ratiometric optical detection of the anion concentration in situ, even under harsh thermal conditions (T = 90 °C). Comparative studies showed that the spectral response is dependent on the type of anion so that carboxylates, weakly coordinating anions and halides can be distinguished.

  20. Podocyte expression of membrane transporters involved in puromycin aminonucleoside-mediated injury.

    Directory of Open Access Journals (Sweden)

    Cristina Zennaro

    Full Text Available Several complex mechanisms contribute to the maintenance of the intricate ramified morphology of glomerular podocytes and to interactions with neighboring cells and the underlying basement membrane. Recently, components of small molecule transporter families have been found in the podocyte membrane, but expression and function of membrane transporters in podocytes is largely unexplored. To investigate this complex field of investigation, we used two molecules which are known substrates of membrane transporters, namely Penicillin G and Puromycin Aminonucleoside (PA. We observed that Penicillin G pre-administration prevented both in vitro and in vivo podocyte damage caused by PA, suggesting the engagement of the same membrane transporters by the two molecules. Indeed, we found that podocytes express a series of transporters which are known to be used by Penicillin G, such as members of the Organic Anion Transporter Polypeptides (OATP/Oatp family of influx transporters, and P-glycoprotein, a member of the MultiDrug Resistance (MDR efflux transporter family. Expression of OATP/Oatp transporters was modified by PA treatment. Similarly, in vitro PA treatment increased mRNA and protein expression of P-glycoprotein, as well as its activity, confirming the engagement of the molecule upon PA administration. In summary, we have characterized some of the small molecule transporters present at the podocyte membrane, focusing on those used by PA to enter and exit the cell. Further investigation will be needed to understand precisely the role of these transporter families in maintaining podocyte homeostasis and in the pathogenesis of podocyte injury.

  1. Laser cooling of molecular anions.

    Science.gov (United States)

    Yzombard, Pauline; Hamamda, Mehdi; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-05-29

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarize the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C_{2}^{-}, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photodetachment process is present, as well as Doppler laser cooling of trapped C_{2}^{-}, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources, and antimatter physics.

  2. Laser Cooling of Molecular Anions

    CERN Document Server

    Yzombard, Pauline; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-01-01

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics.

  3. Calculation of the Isotope Cluster for Polypeptides by Probability Grouping

    Science.gov (United States)

    Olson, Matthew T.; Yergey, Alfred L.

    2014-01-01

    This paper presents a novel theoretical basis for accurately calculating the isotope cluster of polypeptides. In contrast to previous approaches to this problem, which consider exhaustive or near exhaustive combinations of isotopic species, the program, Neutron Cluster, groups probabilities to yield highly accurate information without elucidating any fine structure within a nominal mass unit. This is a fundamental difference from any previously described algorithm for calculating the isotope cluster. As a result of this difference, the accurate isotope clusters for high molecular weight polypeptides can be calculated rapidly without any pruning. When applied to isotope enriched polypeptides, the algorithm introduces “grouping error”, which is described, quantified, and avoided by using probability partitioning. PMID:19026561

  4. Separation, antitumor activities, and encapsulation of polypeptide from Chlorella pyrenoidosa.

    Science.gov (United States)

    Wang, Xiaoqin; Zhang, Xuewu

    2013-01-01

    Chlorella pyrenoidosa is a unicellular green algae and has been a popular foodstuff worldwide. However, no reports on the antitumor peptides from such a microalgae are available in the literature. In this study, using low-temperature high-pressure extraction, enzymatic hydrolysis, ion exchange, and gel filtration chromatography, we separated a polypeptide that exhibited inhibitory activity on human liver cancer HepG2 cells, and named the polypeptide CPAP (C. pyrenoidosa antitumor polypeptide). Furthermore, the micro- and nanoencapsulation of CPAP were investigated by using two methods: complex coacervation and ionotropic gelation. The in vitro release tests revealed that CPAP was well preserved against gastric enzymatic degradation after micro/nanoencapsulation and the slowly controlled release in the intestine could be potentially achieved. These results suggest that CPAP may be a useful ingredient in food, nutraceutical, and pharmaceutical applications. © 2013 American Institute of Chemical Engineers.

  5. Multiple blood-brain barrier transport mechanisms limit bumetanide accumulation, and therapeutic potential, in the mammalian brain.

    Science.gov (United States)

    Römermann, Kerstin; Fedrowitz, Maren; Hampel, Philip; Kaczmarek, Edith; Töllner, Kathrin; Erker, Thomas; Sweet, Douglas H; Löscher, Wolfgang

    2017-05-01

    There is accumulating evidence that bumetanide, which has been used over decades as a potent loop diuretic, also exerts effects on brain disorders, including autism, neonatal seizures, and epilepsy, which are not related to its effects on the kidney but rather mediated by inhibition of the neuronal Na-K-Cl cotransporter isoform NKCC1. However, following systemic administration, brain levels of bumetanide are typically below those needed to inhibit NKCC1, which critically limits its clinical use for treating brain disorders. Recently, active efflux transport at the blood-brain barrier (BBB) has been suggested as a process involved in the low brain:plasma ratio of bumetanide, but it is presently not clear which transporters are involved. Understanding the processes explaining the poor brain penetration of bumetanide is needed for developing strategies to improve the brain delivery of this drug. In the present study, we administered probenecid and more selective inhibitors of active transport carriers at the BBB directly into the brain of mice to minimize the contribution of peripheral effects on the brain penetration of bumetanide. Furthermore, in vitro experiments with mouse organic anion transporter 3 (Oat3)-overexpressing Chinese hamster ovary cells were performed to study the interaction of bumetanide, bumetanide derivatives, and several known inhibitors of Oats on Oat3-mediated transport. The in vivo experiments demonstrated that the uptake and efflux of bumetanide at the BBB is much more complex than previously thought. It seems that both restricted passive diffusion and active efflux transport, mediated by Oat3 but also organic anion-transporting polypeptide (Oatp) Oatp1a4 and multidrug resistance protein 4 explain the extremely low brain concentrations that are achieved after systemic administration of bumetanide, limiting the use of this drug for targeting abnormal expression of neuronal NKCC1 in brain diseases. Copyright © 2017 Elsevier Ltd. All rights

  6. On the theory of phase transitions in polypeptides

    DEFF Research Database (Denmark)

    Yakubovich, Alexander V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2008-01-01

    We suggest a theoretical method based on the statistical mechanics for treating the alpha-helix random coil transition in polypeptides. This process is considered as a first-order-like phase transition. The developed theory is free of model parameters and is based solely on fundamental physical...... principles. We apply the developed formalism for the description of thermodynamical properties of alanine polypeptides of different length. We analyze the essential thermodynamical properties of the system such as heat capacity, phase transition temperature and latent heat of the phase transition...

  7. Anion

    Directory of Open Access Journals (Sweden)

    A. Vadivel Murugan

    2003-01-01

    . Its characterization is investigated by Fourier Transform Infrared Spectroscopy (FT-IR and Scanning Electron Microscopy (SEM. The hybrid material presents predominantly high electronic conductivities of around 2.0 and 7.0 S cm-1 at 300 and 400K respectively.

  8. Decreased anion gap in polyclonal hypergammaglobulinemia.

    Science.gov (United States)

    Qujeq, Durdi; Mohiti, Javad

    2002-02-01

    The anion gap has proved a valuable tool in the diagnosis of various forms of acid-base disorders, although the importance of slight rises in the anion gap remains unclear. The concept of the anion gap is often misunderstood and misapplied. The relationship between gammaglobulins and the serum anion gap has not received much attention except for reports of a narrowing of the gap associated with certain monoclonal immunoglobulin G gammopathies. We present patients with polyclonal gammopathy, the magnitude of which correlated strongly and negatively with the anion gap. The anion gap can be readily calculated from routine laboratory data, and anion gap was calculated as ([Na] +[K])- ([Cl] + [HCO3]). Serum anion gaps were determined in 206 patients with polyclonal hypergammaglobulinemia and 63 healthy subjects. Serum sodium and potassium ions concentration were determined by flame photometry. Serum bicarbonate level was measured as total carbon dioxide content. Serum chloride level was determined by chlorimetric titration with silver ions. All patients with polyclonal hypergammaglobulinemia had a statistically significant reduction in their mean serum anion gaps (6.4 +/- 1.2 mmol/L) when compared with normal control volunteers (15.3 +/- 2.4 mmol/L), p anion gap and gammaglobulins concentration.

  9. Identification of polypeptides by using SOM neural networks

    Science.gov (United States)

    Liu, Jianwei; He, Ting; Zhang, Bo; Shen, Jingling

    2014-11-01

    Sample with no characteristic absorption can be identified by refractive index features. In this work, qualitative and quantitative identification of THz spectra of polypeptides using self-organization feature map (SOM) artificial neural network has been demonstrated. The absorption and refractive index features of three polypeptides, including Argreline Acetate, Alarelin Acetate, and Bivalirudin Trifluoroacetate, were measured by using the terahertz time-domain spectroscopy technique in the range 0.2-2.2 THz. The experimental results show that the three measured polypeptides present high similarity in absorption spectra but difference in refractive index spectra. After the network training process, the collected spectra were identified by the well-trained SOM network at another time. Analyzing the result we can see that the refractive index spectra are clustered and identify much better than the THz spectra of polypeptides. The study indicates that refractive index spectra can also be clustered by the SOM artificial neural network for identification of THz spectra especially when there is no obvious difference in absorption but significant difference in refractive index spectra.

  10. Vasoactive intestinal polypeptide (VIP) in the pig pancreas

    DEFF Research Database (Denmark)

    Poulsen, Steen Seier

    1984-01-01

    Vasoactive intestinal polypeptide (VIP) in the pig pancreas is localized to nerves, many of which travel along the pancreatic ducts. VIP stimulates pancreatic fluid and bicarbonate secretion like secretin. Electrical vagal stimulation in the pig causes an atropine-resistant profuse secretion...

  11. CLE polypeptide signaling gene expression in Arabidopsis embryos

    Science.gov (United States)

    Technical Abstract: The CLAVATA3 (CLV3)/ESR-related (CLE) family of small polypeptides mediate intercellular signaling events in plants. The biological roles of several CLE family members have been characterized, but the function of the majority still remains elusive. We recently performed a system...

  12. Discovery and Characterization of A Novel Class of Functional Polypeptides

    Science.gov (United States)

    Chu, Qian; Ma, Jiao; Saghatelian, Alan

    2015-01-01

    Molecular biology, genomics and proteomics methods have been utilized to reveal a non-annotated class of endogenous polypeptides (small proteins and peptides) encoded by short open reading frames (sORFs), or small open reading frames (smORFs). We refer to these polypeptides as s(m)ORF-encoded polypeptides or SEPs. The early SEPs were identified via genetic screens, and many of the RNAs that contain s(m)ORFs were originally considered to be non-coding; however, elegant work in bacteria and flies demonstrated that these s(m)ORFs code for functional polypeptides as small as 11-amino acids in length. The discovery of these initial SEPs led to searches for these molecules using methods such as ribosome profiling and proteomics, which have revealed the existence of many SEPs, including novel human SEPs. Unlike screens, –omics methods do not necessarily link a SEP to a cellular or biological function, but functional genomic and proteomic strategies have demonstrated that at least some of these newly discovered SEPs have biochemical and cellular functions. Here, we provide an overview of these results and discuss the future directions in this emerging field. PMID:25857697

  13. Immunohistochemical localization of pancreatic spasmolytic polypeptide (PSP) in the pig

    DEFF Research Database (Denmark)

    Raaberg, Lasse; Poulsen, Steen Seier; Thim, L

    1992-01-01

    Pancreatic spasmolytic polypeptide (PSP) is a peptide that is isolated from the porcine pancreas and that affects intestinal motility and growth of intestinal tumour cells in vitro. The peptide was recently demonstrated to be present in large amounts in pancreatic juice. The cellular origin...

  14. Identification and characterization of sORF-encoded polypeptides.

    Science.gov (United States)

    Chu, Qian; Ma, Jiao; Saghatelian, Alan

    2015-01-01

    Molecular biology, genomics and proteomics methods have been utilized to reveal a non-annotated class of endogenous polypeptides (small proteins and peptides) encoded by short open reading frames (sORFs), or small open reading frames (smORFs). We refer to these polypeptides as s(m)ORF-encoded polypeptides or SEPs. The early SEPs were identified via genetic screens, and many of the RNAs that contain s(m)ORFs were originally considered to be non-coding; however, elegant work in bacteria and flies demonstrated that these s(m)ORFs code for functional polypeptides as small as 11-amino acids in length. The discovery of these initial SEPs led to search for these molecules using methods such as ribosome profiling and proteomics, which have revealed the existence of many SEPs, including novel human SEPs. Unlike screens, omics methods do not necessarily link a SEP to a cellular or biological function, but functional genomic and proteomic strategies have demonstrated that at least some of these newly discovered SEPs have biochemical and cellular functions. Here, we provide an overview of these results and discuss the future directions in this emerging field.

  15. Chirality-selected phase behavior in ionic polypeptide complexes

    Science.gov (United States)

    Tirrell, Matthew

    2015-03-01

    We demonstrate that chirality determines the phase state of polyelectrolyte complexes formed from mixing dilute solutions of oppositely charged polypeptides. In these systems, the physical state of the resultant complex is determined by the combination of electrostatic and hydrogen bonding interactions. The formation of fluid complexes occurs when at least one of the polypeptides in the mixture is racemic, which disrupts backbone hydrogen bonding networks. Pairs of purely chiral polypeptides, of any sense, form compact, fibrillar solids with a β-sheet structure on mixing. Analogous behavior occurs in micellar cores formed from polypeptide block copolymers with polyethylene oxide, where microphase separation into discrete, self-assembled aggregates with either solid or fluid cores, and eventually into ordered phases at high concentrations, is possible. Chirality is an exploitable tool for manipulating material properties in systems based on polyelectrolyte complexation. Its role in these systems gives insight into polyelectrolyte complex phase behavior more broadly. This work was supported by the U.S. Department of Energy Office of Science Program in Basic Energy Sciences, Materials Sciences and Engineering Division.

  16. Research progress of active polypeptides of Cordyceps militaris

    Directory of Open Access Journals (Sweden)

    Xu Guangyu

    2017-01-01

    Full Text Available It is recognized at home and abroad that Cordyceps militaris is a fungus that can be edible and used for medicinal application, and also a common cordyceps taishanensis that is widely distributed and with very high medicinal value in China. Active Cordyceps militaris polypeptide has shown several highlights in its absorption mechanism, such as directly absorbed without the need for digestion, and absorbed quickly and completely, and more and more international researchers are attaching great importance to it. Physiological and pharmacological activities of Cordyceps militaris polypeptide are mainly to activate related enzyme systems, promote intermediary metabolisms or control the DNA transcription and translation, simultaneously activate the reticuloendothelial system and macrophage, promote the transformation of lymphocytes, and as a nonspecific immune enhancer and regulator, activate the immune competent cells, especially lymphocytes, lymphokines, mononuclear macrophage system and NK cells, thereby attacking the target cells to play an antitumor role, and also exerting its anti-aging, anticoagulant, hypolipidemic to enhance the immunity, improve the liver function and delay the aging. In this paper, the immunity improvement, anticancer, antioxidation and antimicrobial activities of active polypeptides from Cordyceps militaris are reviewed, in order to provide a solid theoretical help for the further development and application of active polypeptides of Cordyceps militaris.

  17. Drugs interacting with organic anion transporter-1 affect uptake of Tc-99m-mercaptoacetyl-triglycine (MAG3) in the human kidney: Therapeutic drug interaction in Tc-99m-MAG3 diagnosis of renal function and possible application of Tc-99m-MAG3 for drug development

    International Nuclear Information System (INIS)

    Takahara, Noriko; Saga, Tsuneo; Inubushi, Masayuki; Kusuhara, Hiroyuki; Seki, Chie; Ito, Sumito; Oyama, Nobuyuki; Yokoyama, Osamu; Sugiyama, Yuichi; Fujibayashi, Yasuhisa

    2013-01-01

    Introduction: Renal uptake of Tc-99m-MG3 involves organic anion transporter (OAT). Treatment with drugs showing OAT affinity might interfere with renal uptake of Tc-99m-MAG3, leading to misinterpretation in Tc-99m-MAG3. This study was conducted to discuss a possible drug interference with Tc-99m-MAG3 diagnosis on OAT sites. Methods: Renal uptake and plasma clearance of Tc-99m-MAG3 were analyzed in healthy volunteers under control and OAT1 and OAT3 related drug treatment conditions. An in vitro uptake study using OAT1 or OAT3 expressing cells was also conducted. Results: Both PAH and probenecid treatment induced delays in Tc-99m-MAG3 clearance from blood, and reductions in the renal uptake clearance. As a result, the normalized effective renal plasma flow estimated from Tc-99m-MAG3 clearance was significantly underestimated, whereas the glomerular filtration rate estimated from plasma creatinine levels was unchanged. The transport activity of Tc-99m-MAG3 was higher in OAT1-expressing cells than in OAT3-expressing cells. Conclusion: Drugs with OAT1 affinity affect the renal uptake of Tc-99m-MAG3 and blood clearance. This might cause misinterpretation of functional diagnosis of the kidney using Tc-99m-MAG3

  18. The polypeptide in Chlamys farreri can protect human dermal fibroblasts from ultraviolet B damage

    Science.gov (United States)

    Zhang, Yujiang; Zhan, Songmei; Cao, Pengli; Liu, Ning; Chen, Xuehong; Wang, Yuejun; Wang, Chunbo

    2005-09-01

    To investigate the effect of polypeptide from Chlamys farreri (PCF) on NHDF in vitro, we modeled oxidative damage on normal human dermal fibroblasts (NHDF) exposed to ultraviolet B (UVB). In this study, 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) were tested to measure cell viability. Enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT) and xanthine oxidase (XOD) were determined biochemically. Total antioxidative capacity (T-AOC) and anti-superoxide anion capacity (A-SAC) were also determined. Ultrastructure of fibroblasts was observed under transmission electron microscope. The results showed that: UVB (1.176×10-4 J/cm2) suppressed the growth of fibroblasts and the introduction of PCF (0.25% 1%) before UVB reduced the suppression in a concentration-dependent manner. PCF could enhance the activities of SOD, GSH-PX and T-AOC as well as A-SAC. Also PCF could inhibit XOD activity, while it did not affect CAT activity. Ultrastructure of fibroblasts were damaged after UVB irradiation, concentration-dependent PCF reduced the destructive effect of UVB on cells. These results indicated that PCF can protect human dermal fibroblasts from being harmed by UVB irradiation via its antioxidant proerty.

  19. Drug transport proteins in the liver

    NARCIS (Netherlands)

    Faber, Klaas Nico; Muller, M.; Jansen, P.LM

    2003-01-01

    Together with drug metabolising enzymes, transmembrane transporters are important determinants of drug metabolism and drug clearance by the liver. Hepatic uptake of organic anions, cations, prostaglandins and bile salts is supported by dedicated transporter proteins in the basolateral (sinusoidal)

  20. Environmental behavior of inorganic anions

    International Nuclear Information System (INIS)

    Garland, T.R.; Cataldo, D.A.; Fellows, R.J.; Wildung, R.E.

    1987-01-01

    Recent efforts have addressed two aspects of anion behavior in the soil/plant system. The first involves evaluation of the gaseous component of the terrestrial iodine cycle in soils and plants. Field analyses of 129 I in soils and vegetation adjacent to a fuels reprocessing facility, which was idle for 10 years prior to the study, indicated that there may be a significant gaseous component to the terrestrial iodine cycle. Soil substrates, including a silt-sand, organic forest soil, quartz sand, and a sterilized soil, were amended with radioiodide, and the rates and quality of the volatile components evaluated

  1. Revisiting the Helical Cooperativity of Synthetic Polypeptides in Solution.

    Science.gov (United States)

    Ren, Yuan; Baumgartner, Ryan; Fu, Hailin; van der Schoot, Paul; Cheng, Jianjun; Lin, Yao

    2017-08-14

    Using synthetic polypeptides as a model system, the theories of helix-coil transition were developed into one of the most beautiful and fruitful subjects in macromolecular science. The classic models proposed by Schellman and Zimm-Bragg more than 50 years ago, differ in the assumption on whether the configuration of multiple helical sequences separated by random coil sections is allowed in a longer polypeptide chain. Zimm also calculated the critical chain lengths that facilitate such interrupted helices in different solvent conditions. The experimental validation of Zimm's prediction, however, was not carefully examined at that time. Herein, we synthesize a series of homopolypeptide samples with different lengths, to systematically examine their helix-coil transition and folding cooperativity in solution. We find that for longer chains, polypeptides do exist as interrupted helices with scattered coil sections even in helicogenic solvent conditions, as predicted in the Zimm-Bragg model. The critical chain lengths that facilitate such interrupted helices, however, are substantially smaller than Zimm's original estimation. The inaccuracy is in part due to an approximation that Zimm made in simplifying the calculation. But more importantly, we find there exist intramolecular interactions between different structural segments in the longer polypeptides, which are not considered in the classic helix-coil theories. As such, even the Zimm-Bragg model in its exact form cannot fully describe the transition behavior and folding cooperativity of longer polypeptides. The results suggest that long "all-helix" chains may be much less prevalent in solution than previously imagined, and a revised theory is required to accurately account for the helix-coil transition of the longer chains with potential "non-local" intramolecular interactions.

  2. Polypeptides having beta-glucosidase activity and polynucleotides encoding the same

    Science.gov (United States)

    Brown, Kimberly; Harris, Paul

    2013-12-17

    The present invention relates to isolated polypeptides having beta-glucosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  3. Polypeptides having beta-glucosidase and beta-xylosidase activity and polynucleotides encoding same

    Science.gov (United States)

    Morant, Marc Dominique

    2014-05-06

    The present invention relates to isolated polypeptides having beta-glucosidase activity, beta-xylosidase activity, or beta-glucosidase and beta-xylosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  4. Recombinant host cells and nucleic acid constructs encoding polypeptides having cellulolytic enhancing activity

    Science.gov (United States)

    Schnorr, Kirk; Kramer, Randall

    2017-03-28

    The present invention relates to isolated polypeptides having cellulolytic enhancing activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  5. Polypeptides having beta-glucosidase activity and beta-xylosidase activity and polynucleotides encoding same

    Science.gov (United States)

    Morant, Marc Dominique

    2014-04-29

    The present invention relates to isolated polypeptides having beta-glucosidase activity, beta-xylosidase activity, or beta-glucosidase and beta-xylosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.

  6. Interstellar Anions: The Role of Quantum Chemistry.

    Science.gov (United States)

    Fortenberry, Ryan C

    2015-10-01

    Six anions have been conclusively detected in the interstellar medium (ISM). They all arrived within a five-year window ending five years ago. Why have no new anions been detected? It is likely a lack of laboratory data for novel anions. This work reviews the role that valence and dipole-bound excited states may play in the formation, detection, and lifetime of anions that may yet be observed in the ISM and how quantum chemistry enhances this understanding. The list of interstellar anions has certainly not been exhausted by any means, but electronic, spectroscopic, and structural data must be provided to aid in any future detections. Quantum chemistry has the flexibility and completeness to provide a full picture of these systems and has shown exceptional accuracies of late. The work reviewed herein gives an overview of what quantum chemical computations have produced and will continue to provide related to anions and how this will enhance both laboratory experiment and astronomical observation.

  7. Clinical usefulness of the serum anion gap.

    Science.gov (United States)

    Lee, Sik; Kang, Kyung Pyo; Kang, Sung Kyew

    2006-03-01

    The anion gap in the serum is useful in the interpretation of acid-base disorders and in the diagnosis of other conditions. In the early 1980s, ion-selective electrodes for specific ionic species were introduced for the measurement of serum electrolytes. This new method has caused a shift of the anion gap from 12±4 mEq/L down 6±3 mEq/L. It is worthy for clinicians to understand the range of normal anion gap and the measuring methods for serum sodium and chloride in the laboratories that support their practice. While an increase in the anion gap is almost always caused by retained unmeasured anions, a decrease in the anion gap can be generated by multiple mechanisms.

  8. Biophysical studies of membrane channel polypeptides

    CERN Document Server

    Galbraith, T P

    2001-01-01

    Membrane channels facilitate the flow of ions across biological membranes, a process which is important in numerous cellular functions. The study of large integral membrane proteins is made difficult by identification, production and purification problems, and detailed knowledge of their three-dimensional structures is relatively scarce. The study of simple 'model' membrane proteins has given valuable insight into the structures and dynamics of membrane proteins in general. The bacterial peptide gramicidin has been the subject of intense study for many years, and has provided important information into the structural basis of channel function. Peptaibols, a class of fungal membrane peptides which includes alamethicin and antiamoebin, have also been useful in relating structural details to molecular ion transport processes. Gramicidin crystals were grown in the presence of phospholipids with various headgroups and acyl chains. The diffraction patterns of the crystals obtained were processed, but found to be in...

  9. Schlenk Techniques for Anionic Polymerization

    KAUST Repository

    Ratkanthwar, Kedar

    2015-09-01

    Anionic polymerization-high vacuum techniques (HVTs) are doubtlessly the most prominent and reliable experimental tools to prepare polymer samples with well-defined and, in many cases, complex macromolecular architectures. Due to the high demands for time and skilled technical personnel, HVTs are currently used in only a few research laboratories worldwide. Instead, most researchers in this filed are attracted to more facile Schlenk techniques. The basic principle of this technique followed in all laboratories is substantially the same, i.e. the use of alternate vacuum and inert gas atmosphere in glass apparatus for the purification/charging of monomer, solvents, additives, and for the manipulation of air-sensitive compounds such as alkyl metal initiators, organometallic or organic catalysts. However, it is executed quite differently in each research group in terms of the structure of Schlenk apparatus (manifolds, connections, purification/storage flasks, reactors, etc.), the use of small supplementary devices (soft tubing, cannulas, stopcocks, etc.) and experimental procedures. The operational methods are partly purpose-oriented while also featured by a high flexibility, which makes it impossible to describe in detail each specific one. In this chapter we will briefly exemplify the application of Schlenk techniques for anionic polymerization by describing the performance of a few experiments from our own work.

  10. Effect of chemical retention on anionic species diffusion in compacted clays

    International Nuclear Information System (INIS)

    Bazer-Bachi, Frederic

    2005-01-01

    Anionic radioisotopes are of particular importance within the framework of the calculated health risk associated with high-level and long-lived intermediate-level underground radioactive waste disposal. Therefore, the objective of this work is the construction of a transport model coupled with chemistry in order to quantify the behaviour of anionic solutes in the Callovo-Oxfordian (CO x ) argillite, the argillaceous host rock of the ANDRA Meuse/Haute-Marne underground laboratory. An experimental methodology was defined to characterize this migration, several experimental methods being implemented: batch experiments, laboratory columns and through-diffusion cells. The study of the diffusion of the non-sorbing anionic tracer 36 Cl - highlighted the fact that, due to anionic exclusion, anions only had access to a part of the porosity. The retention of 35 SO 4 2- and 125 I- on CO x argillite was then characterized, quantified by batch experiments and confirmed by other experimental methods. Nevertheless, their migration was less retarded than expected by a model based on batch experiments and on 36 Cl - diffusive data. This difference was explained by anion exclusion which reduced sorption site accessibility. Thus, the intensity of this phenomenon has to be considered to model anion migration in compacted clays. (author) [fr

  11. Electrolyte secretion by the isolated cat pancreas during replacement of extracellular bicarbonate by organic anions and chloride by inorganic anions.

    Science.gov (United States)

    Case, R M; Hotz, J; Hutson, D; Scratcherd, T; Wynne, R D

    1979-01-01

    acetate. 7. These observations illustrate that an extracellular source of permeant anions is required for optimal pancreatic bicarbonate secretion to occur. This may indicate the participation of an anion exchange carrier in the transport events responsible for this secretory process.

  12. An engineered coiled-coil polypeptide assembled onto quantum dots for targeted cell imaging

    Science.gov (United States)

    Yao, Ming-Hao; Yang, Jie; Song, Ji-Tao; Zhang, Lin; Fang, Bi-Yun; Zhao, Dong-Hui; Xia, Rui-Xue; Jin, Rui-Mei; Zhao, Yuan-Di; Liu, Bo

    2015-12-01

    Quantum dot (QD)-polypeptide probes have been developed through the specific metal-affinity interaction between polypeptides appended with N-terminal polyhistidine sequences and CdSe/ZnS core-shell QDs. The size and charge of a QD-polypeptide can be tuned by using different coiled-coil polypeptides. Compared to glutathione-capped QDs (QD-GSH), QD-polypeptide probes showed an approximately two- to three-fold luminescence increase, and the luminescence increase was not obviously related to the charge of the polypeptide. QD-polypeptide probes with different charge have a great effect on nonspecific cellular uptake. QD-polypeptide probes with negative charge exhibited lower nonspecific cellular uptake in comparison to the QD-GSH, while positively charged QD-polypeptide probes presented higher cellular uptake than the QD-GSH. A targeted QD-ARGD probe can obviously increase targeted cellular uptake in α v β 3 overexpressing HeLa cells compared to QD-A. In addition, QD-polypeptide probes showed lower in vitro cytotoxicity compared to the original QDs. These results demonstrate that these QD-polypeptide probes with high specific cellular uptake, high fluorescence intensity and low background noise are expected to have great potential applications in targeted cell imaging.

  13. Ionic Block Copolymers for Anion Exchange Membranes

    Science.gov (United States)

    Tsai, Tsung-Han; Herbst, Dan; Giffin, Guinevere A.; di Noto, Vito; Witten, Tom; Coughlin, E. Bryan

    2013-03-01

    Anion exchange membrane (AEM) fuel cells have regained interest because it allows the use of non-noble metal catalysts. Until now, most of the studies on AEM were based on random polyelectrolytes. In this work, Poly(vinylbenzyltrimethylammonium bromide)-b- (methylbutylene) ([PVBTMA][Br]-b-PMB) was studied by SAXS, TEM and dielectric spectroscopy to understand the fundamental structure-conductivity relationship of ion transport mechanisms within well-ordered block copolymers. The ionic conductivity and the formation of order structure were dependent on the casting solvent. Higher ion exchange capacity (IEC) of the membranes showed higher conductivity at as IEC values below 1.8mmol/g, as above this, the ionic conductivity decreases due to more water uptake leading to dilution of charge density. The humidity dependence of morphology exhibited the shifting of d-spacing to higher value and the alteration in higher characteristic peak of SAXS plot as the humidity increase from the dry to wet state. This phenomenon can be further explained by a newly developed polymer brush theory. Three ionic conduction pathways with different conduction mechanism within the membranes can be confirmed by broadband electric spectroscopy. US Army MURI (W911NF1010520)

  14. High molecular weight polypeptide bands specific for equine herpesvirus 4.

    Science.gov (United States)

    Zheng, M; Love, D N; Sabine, M

    1995-09-01

    Serum neutralisation (SN) and immunoblotting were used in attempts to distinguish between natural infections with the closely related viruses equine herpesvirus 1 (EHV-1) and equine herpes-virus 4 (EHV-4). Horse sera (n = 323) collected in 1990 from studs with no experience of EHV-1 abortions as well as 197 sera collected in 1992 from studs with a history of EHV-1 abortions were tested by SN. The two groups differed in the proportion with measurable EHV-1 antibody, the 1992 group being significantly higher. Both groups had high proportions with EHV-4 antibody and no serum had antibody to EHV-1 alone. Pools of positive sera were prepared as probes in immunoblots. High molecular weight (> 200 kDa) polypeptide bands specific for EHV-4 were detected. No bands specific for EHV-1 only were found. The specific EHV-4 polypeptides shared some properties with gp2 of EHV-1.

  15. Compositions and methods for making selenocysteine containing polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Soll, Dieter; Aldag, Caroline; Hohn, Michael

    2016-10-11

    Non-naturally occurring tRNA.sup.Sec and methods of using them for recombinant expression of proteins engineered to include one or more selenocysteine residues are disclosed. The non-naturally occurring tRNA.sup.Sec can be used for recombinant manufacture of selenocysteine containing polypeptides encoded by mRNA without the requirement of an SECIS element. In some embodiments, selenocysteine containing polypeptides are manufactured by co-expressing a non-naturally occurring tRNA.sup.Sec a recombinant expression system, such as E. coli, with SerRS, EF-Tu, SelA, or PSTK and SepSecS, and an mRNA with at least one codon that recognizes the anticodon of the non-naturally occurring tRNA.sup.Sec.

  16. Imparting large macroscopic changes with small changes in polypeptide composition

    Science.gov (United States)

    Sing, Michelle; McKinley, Gareth; Olsen, Bradley

    Block copolymers composed of polypeptides provide an excellent platform for exploring the underlying physics surrounding macroscopic associative network behavior. Previous work in our group has elucidated a difference in the mechanical properties of two nearly identical elastin-like polypeptide (ELP) endblocks. In poly(ELP)s, this substitution is known to result in tighter beta turns. These beta turns exhibit slower responses to changes in temperature within the material. Under shear, the modulus for the alanine-containing ELP triblock is almost three times higher than the glycine-containing ELP. Additionally, preliminary tensile tests show higher stress and strain at break for the alanine ELP triblock. We are able to explain the reasons for this behavior using a variety of spectroscopic and analytical techniques. Small angle neutron and x-ray scattering indicate differences in ordering between the alanine and glycine containing ELP materials both in shear and in stagnant flow.

  17. ANIONS FUNCTIONS IN TRANSITION METALS COORDINATION COMPOUNDS

    Directory of Open Access Journals (Sweden)

    T. V. Koksharova

    2016-04-01

    Full Text Available The effect of anions on the structure and properties of coordination compounds of transition metals has been discussed. The examples of changes in the composition of the formed complexes by replacement of the anion are given: metal ratio to a neutral ligand, the composition of the inner sphere, the direction of template synthesis. Anions can determine the presence of isomers in complexes with different ligands. Examples of conformational, ionization isomerism, inner sphere bond isomerization are given. The nature of the coordination polyhedron is highly sensitive to the replacement of the anion too. Examples of coordination compounds where the anion change causes a change in coordination capacity of neutral ligands and the strength of their bonds with the metal, coordination number and geometry of the inner sphere, the organization of molecular structures (the structure of the hydrogen bond networks and the degree of polymerization, crystal packing. The anions significantly affect the binding of the solvent molecules, complexes magnetic and luminescent properties, they can change the compound color, the mechanisms of thermolysis. Anions make a very noticeable influence on possible redox processes following the complexation in some cases. Anions in the coordination sphere can change catalytic and biochemical processes as well as the ways of interaction of metal ions with drugs.

  18. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Unknown

    Indian Academy of Sciences. 671. The many ways of making anionic ... In all these cases, the negative charge is compensated for by the inclusion of positive ions in the interlayer region, by virtue ..... as anionic clays. Acknowledgements. The authors thank the Department of Science and Technology, New Delhi for financial.

  19. Test procedure for anion exchange chromatography

    International Nuclear Information System (INIS)

    Cooper, T.D.

    1994-01-01

    Plutonium from stored nitrate solutions will be sorbed onto anion exchange resins and converted to storable plutonium dioxide. Useful information will be simultaneously gained on the thermal stability and ion exchange capacity of four commercially available anion exchange resins over several years and under severe degradative conditions. This information will prove useful in predicting the safe and efficient lifetimes of these resins

  20. Hydrogen in anion vacancies of semiconductors

    Science.gov (United States)

    Du, Mao-Hua; Singh, David

    2009-03-01

    Hydrogen typically terminates the dangling bonds around vacancies in semiconductors, thereby, partially or completely passivating the vacancies. However, it has been shown recently that hydrogen in anion vacancies of many semiconductors, such as ZnO, MgO, InN, SnO2, and GaN, takes multi-coordinated structures and acts as shallow donors, providing n-type conductivity to the materials. We study the hydrogen in the anion vacancies of a series of II-VI and III-V semiconductors using density functional calculations. The results on these materials show that, in the anion vacancies of polar II-VI semiconductors, the hydrogen is usually anionic and is coordinated with more than one cation atoms as a result of the relatively high ionicity of the host materials. The hydrogen coordination number depends on the host anion size. On the other hand, in more covalent semiconductors such as some III-V semiconductors, the single cation-H bonding configuration may become most stable. In the anion vacancies of ZnX and CdX where X represents anions, hydrogen is typically amphoteric except for oxides, in which the small anion size prohibits the formation of the cation-cation bond that is required for the acceptor configuration.

  1. Simultaneous anion and cation mobility in polypyrrole

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; Vidanapathirana, K.

    2003-01-01

    Polypyrrole (PPy) polymer films permanently doped with large, immobile anion dodecyl benzene sulfonate (DBS) have been characterized by cyclic voltammetry in order to clarify the roles of cations and anions in the aqueous electrolyte as mobile ions in the film. Aqueous solutions of 0.05-0.1 M...

  2. NMR study of the cooperative behavior of thermotropic model polypeptides

    Czech Academy of Sciences Publication Activity Database

    Kurková, Dana; Kříž, Jaroslav; Rodríguez-Cabello, J. C.; Arias, F. J.

    2007-01-01

    Roč. 56, č. 2 (2007), s. 186-194 ISSN 0959-8103 R&D Projects: GA AV ČR IAA400500604 Grant - others:Spanish Ministry of Science and Culture (ES) A002/02; MAT2000-1764-C02; MAT2001-1853-C02-01; MAT2003- Institutional research plan: CEZ:AV0Z40500505 Keywords : thermotropic polymers * cooperativity * synthetic polypeptides Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.557, year: 2007

  3. Inhibition of the coated vesicle proton pump and labeling of a 17,000-dalton polypeptide by N,N'-dicyclohexylcarbodiimide

    International Nuclear Information System (INIS)

    Arai, H.; Berne, M.; Forgac, M.

    1987-01-01

    N,N'-Dicyclohexylcarbodiimide (DCCD) inhibits 100% of proton transport and 80-85% of (Mg2+)-ATPase activity in clathrin-coated vesicles. Half-maximum inhibition of proton transport is observed at 10 microM DCCD after 30 min. Although treatment of the coated vesicle (H+)-ATPase with DCCD has no effect on ATP hydrolysis in the detergent-solubilized state, sensitivity of proton transport and ATPase activity to DCCD is restored following reconstitution into phospholipid vesicles. In addition, treatment of the detergent-solubilized enzyme with DCCD followed by reconstitution gives a preparation that is blocked in both proton transport and ATP hydrolysis. These results suggest that although the coated vesicle (H+)-ATPase can react with DCCD in either a membrane-bound or detergent-solubilized state, inhibition of ATPase activity is only manifested when the pump is present in sealed membrane vesicles. To identify the subunit responsible for inhibition of the coated vesicle (H+)-ATPase by DCCD, we have labeled the partially purified enzyme with [ 14 C]DCCD. A single polypeptide of molecular weight 17,000 is labeled. The extremely hydrophobic nature of this polypeptide is indicated by its extraction with chloroform:methanol. The 17,000-dalton protein can be labeled to a maximum stoichiometry of 0.99 mol of DCCD/mol of protein with 100% inhibition of proton transport occurring at a stoichiometry of 0.15-0.20 mol of DCCD/mol of protein. Amino acid analysis of the chloroform:methanol extracted 17,000-dalton polypeptide reveals a high percentage of nonpolar amino acids. The similarity in properties of this protein and the DCCD-binding subunit of the coupling factor (H+)-ATPases suggests that the 17,000-dalton polypeptide may function as part of a proton channel in the coated vesicle proton pump

  4. Fungal growth on anion surfactant medium.

    Science.gov (United States)

    Hamada, Nobuo; Abe, Niichiro

    2009-12-01

    Before the present study, no fungi using anion surfactant as a nutrient had been identified, although some fungi were known to use nonion surfactant. Washing water collected from 63 washing machines was inoculated onto 0.1% LAS (Sodium dodecyl benzenesulfonate) anion surfactant media to identify fungi that can feed on anion-surfactant. Small dark colonies of fungi were found on several of the Petri-dishes from 12 days after inoculation. These were identified as Cladophialophora boppii and Exophiala spinifera using morphological features and rDNA data. A number of the isolates of C. boppii specifically were recognized as using anion surfactant as a nutrient. The growth characteristics of the two fungal species were examined on surfactant media of three kinds. Apart from anion surfactant, the fungi were also able to grow on nonion surfactant and on soap. The application of these fungi for environmental cleansing after detergent pollution is also discussed.

  5. Creating molecular macrocycles for anion recognition

    Directory of Open Access Journals (Sweden)

    Amar H. Flood

    2016-03-01

    Full Text Available The creation and functionality of new classes of macrocycles that are shape persistent and can bind anions is described. The genesis of triazolophane macrocycles emerges out of activity surrounding 1,2,3-triazoles made using click chemistry; and the same triazoles are responsible for anion capture. Mistakes made and lessons learnt in anion recognition provide deeper understanding that, together with theory, now provides for computer-aided receptor design. The lessons are acted upon in the creation of two new macrocycles. First, cyanostars are larger and like to capture large anions. Second is tricarb, which also favors large anions but shows a propensity to self-assemble in an orderly and stable manner, laying a foundation for future designs of hierarchical nanostructures.

  6. Closing the gap on unmeasured anions

    Science.gov (United States)

    Kellum, John A

    2003-01-01

    Many critically ill and injured patients, especially those with metabolic acidosis, have abnormally high levels of unmeasured anions in their blood. At the same time, such patients are prone to hypoalbuminemia, which makes the traditional anion gap calculation inaccurate. Thus, little is known about the epidemiology and clinical consequences of an excess in unmeasured anions in the blood. Indeed, even the etiology of these "missing ions" is often unclear. Unfortunately, more precise means of quantifying unmeasured anions, such as the strong ion gap (SIG), are cumbersome to use clinically. However, a simple means of correcting the anion gap can be used to estimate SIG and may provide additional insight into this common clinical problem. PMID:12793870

  7. Generation of polypeptide-templated gold nanoparticles using ionizing radiation.

    Science.gov (United States)

    Walker, Candace Rae; Pushpavanam, Karthik; Nair, Divya Geetha; Potta, Thrimoorthy; Sutiyoso, Caesario; Kodibagkar, Vikram D; Sapareto, Stephen; Chang, John; Rege, Kaushal

    2013-08-13

    Ionizing radiation, including γ rays and X-rays, are high-energy electromagnetic radiation with diverse applications in nuclear energy, astrophysics, and medicine. In this work, we describe the use of ionizing radiation and cysteine-containing elastin-like polypeptides (C(n)ELPs, where n = 2 or 12 cysteines in the polypeptide sequence) for the generation of gold nanoparticles. In the presence of C(n)ELPs, ionizing radiation doses higher than 175 Gy resulted in the formation of maroon-colored gold nanoparticle dispersions, with maximal absorbance at 520 nm, from colorless metal salts. Visible color changes were not observed in any of the control systems, indicating that ionizing radiation, gold salt solution, and C(n)ELPs were all required for nanoparticle formation. The hydrodynamic diameters of nanoparticles, determined using dynamic light scattering, were in the range of 80-150 nm, while TEM imaging indicated the formation of gold cores 10-20 nm in diameter. Interestingly, C2ELPs formed 1-2 nm diameter gold nanoparticles in the absence of radiation. Our results describe a facile method of nanoparticle formation in which nanoparticle size can be tailored based on radiation dose and C(n)ELP type. Further improvements in these polypeptide-based systems can lead to colorimetric detection of ionizing radiation in a variety of applications.

  8. Separation and nanoencapsulation of antitumor polypeptide from Spirulina platensis.

    Science.gov (United States)

    Zhang, Bochao; Zhang, Xuewu

    2013-01-01

    Spirulina platensis is a multicellular edible blue-green alga with abundant proteins (∼ 60%). No report is available on the antitumor polypeptides from the whole proteins of S. platensis. In this study, for the first time, an antitumor polypeptide Y2 from trypsin digest of S. platensis proteins was obtained by using freeze-thawing plus ultrasonication extraction, hydrolysis with four enzymes (trypsin, alcalase, papain, and pepsin), and gel filtration chromatography. The results showed that the degree of hydrolysis can be ordered as: trypsin (38.5%) > alcalase (31.2%) > papain (27.8%) > pepsin (7.1%). For MCF-7 and HepG2 cells, at 250 µg/mL, the maximum inhibitory rate of Y2 was 97%, while standard drug 5-FU was 55 and 97%, respectively. Furthermore, the nanoencapsulation of Y2 with chitosan (CS) was also investigated. After nanoencapsulation, the maximum encapsulation efficiency and polypeptides contents are 49 and 15%, respectively; and the antitumor activity is basically not lost. These data demonstrated the potential of nanopolypeptides (Y2-CS) in food and pharmaceutical applications. © 2013 American Institute of Chemical Engineers.

  9. Anion Gap Blood Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... https://medlineplus.gov/labtests/aniongapbloodtest.html Anion Gap Blood Test To use the sharing features on this page, please enable JavaScript. What is an Anion Gap Blood Test? An anion gap blood test is a way ...

  10. Alkaline Anion-Exchange Membranes Containing Mobile Ion Shuttles.

    Science.gov (United States)

    Ge, Xiaolin; He, Yubin; Guiver, Michael D; Wu, Liang; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2016-05-01

    A new class of alkaline anion-exchange membranes containing mobile ion shuttles is developed. It is achieved by threading ionic linear guests into poly(crown ether) hosts via host-guest molecular interaction. The thermal- and pH-triggered shuttling of ionic linear guests remarkably increases the solvation-shell fluctuations in inactive hydrated hydroxide ion complexes (OH(-) (H2 O)4 ) and accelerates the OH(-) transport. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Clinical Usefulness of the Serum Anion Gap

    OpenAIRE

    Lee, Sik; Kang, Kyung Pyo; Kang, Sung Kyew

    2006-01-01

    The anion gap in the serum is useful in the interpretation of acid-base disorders and in the diagnosis of other conditions. In the early 1980s, ion-selective electrodes for specific ionic species were introduced for the measurement of serum electrolytes. This new method has caused a shift of the anion gap from 12±4 mEq/L down 6±3 mEq/L. It is worthy for clinicians to understand the range of normal anion gap and the measuring methods for serum sodium and chloride in the laboratories that suppo...

  12. MODERN TECHNOLOGY OF ANIONIC POLYMERIZATION MONOMERS

    Directory of Open Access Journals (Sweden)

    A. V. Tkachev

    2013-01-01

    Full Text Available The preconditions of use in the manufacture of automobile tyres of vulcanizates-based mortar butadienestyrene rubber with a high content of 1.2 links butadiene and statistical distribution of styrene are formulated. Set out scientific researches in the field of anionic co-polymerization of diene and vinyl aromatic monomers. Formulation of catalytic systems applied in processes of anionic copolymerization of monomers are given. The reasons of formation of gel in the process of anionic polymerization of monomers and terms of their elimination are considered.

  13. Polypeptide having or assisting in carbohydrate material degrading activity and uses thereof

    Science.gov (United States)

    Schooneveld-Bergmans, Margot Elisabeth Francoise; Heijne, Wilbert Herman Marie; Los, Alrik Pieter

    2016-02-16

    The invention relates to a polypeptide which comprises the amino acid sequence set out in SEQ ID NO: 2 or an amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 1, or a variant polypeptide or variant polynucleotide thereof, wherein the variant polypeptide has at least 76% sequence identity with the sequence set out in SEQ ID NO: 2 or the variant polynucleotide encodes a polypeptide that has at least 76% sequence identity with the sequence set out in SEQ ID NO: 2. The invention features the full length coding sequence of the novel gene as well as the amino acid sequence of the full-length functional polypeptide and functional equivalents of the gene or the amino acid sequence. The invention also relates to methods for using the polypeptide in industrial processes. Also included in the invention are cells transformed with a polynucleotide according to the invention suitable for producing these proteins.

  14. Basal serum pancreatic polypeptide is dependent on age and gender in an adult population

    DEFF Research Database (Denmark)

    Brimnes Damholt, M; Rasmussen, B K; Hilsted, L

    1997-01-01

    This study is the first epidemiologically based study of basal levels of serum pancreatic polypeptide (s-PP). The basal level of serum PP has become a field of interest mainly due to the role of PP as an endocrine tumour marker, and as a marker of pancreatic neuroendocrine function after pancreas...... a monospecific radioimmunoassay. Fasting serum pancreatic polypeptide depended on age and gender. The results demonstrated that fasting pancreatic polypeptide levels increase exponentially with age. Fitted separately for each sex, basal serum pancreatic polypeptide was found to increase by approximately 3% per...... reports on the fasting levels of serum pancreatic polypeptide are most likely due to lack of adjustment for age and gender. Thus, variation due to age and gender should be considered in evaluating fasting levels of serum pancreatic polypeptide. Whether similar considerations are important when evaluating...

  15. A New in Vitro Anti-Tumor Polypeptide Isolated from Arca inflata

    Directory of Open Access Journals (Sweden)

    Jian Xu

    2013-12-01

    Full Text Available A new in vitro anti-tumor polypeptide, coded as J2-C3, was isolated from Arca inflata Reeve and purified by diethyl-aminoethanol (DEAE-sepharose Fast Flow anion exchange and phenyl sepharose CL-4B hydrophobic chromatography. J2-C3 was identified to be a homogeneous compound by native polyacrylamide gel electrophoresis (Native-PAGE. The purity of J2-C3 was over 99% in reversed phase-high performance liquid chromatography (RP-HPLC. The molecular weight was determined as 20,538.0 Da by electrospray-ionization mass spectrometry (ESI-MS/MS. J2-C3 was rich in Glx (Gln + Glu, Lys, and Asx (Asp + Asn according to amino acid analysis. Four partial amino acid sequences of this peptide were determined as L/ISMEDVEESR, KNGMHSI/LDVNHDGR, AMKI/LI/LNPKKGI/LVPR and AMGAHKPPKGNEL/IGHR via MALDI-TOF/TOF-MS and de novo sequencing. Secondary structural analysis by CD spectroscopy revealed that J2-C3 had the α-helix (45.2%, β-sheet (2.9%, β-turn (26.0% and random coil (25.9%. The anti-tumor effect of J2-C3 against human tumor cells was measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay, and the IC50 values of J2-C3 were 65.57, 93.33 and 122.95 µg/mL against A549, HT-29 and HepG2 cell lines, respectively. Therefore, J2-C3 might be developed as a potential anti-tumor agent.

  16. Experimental evidence for the functional relevance of anion-π interactions

    Science.gov (United States)

    Dawson, Ryan E.; Hennig, Andreas; Weimann, Dominik P.; Emery, Daniel; Ravikumar, Velayutham; Montenegro, Javier; Takeuchi, Toshihide; Gabutti, Sandro; Mayor, Marcel; Mareda, Jiri; Schalley, Christoph A.; Matile, Stefan

    2010-07-01

    Attractive in theory and confirmed to exist, anion-π interactions have never really been seen at work. To catch them in action, we prepared a collection of monomeric, cyclic and rod-shaped naphthalenediimide transporters. Their ability to exert anion-π interactions was demonstrated by electrospray tandem mass spectrometry in combination with theoretical calculations. To relate this structural evidence to transport activity in bilayer membranes, affinity and selectivity sequences were recorded. π-acidification and active-site decrowding increased binding, transport and chloride > bromide > iodide selectivity, and supramolecular organization inverted acetate > nitrate to nitrate > acetate selectivity. We conclude that anion-π interactions on monomeric surfaces are ideal for chloride recognition, whereas their supramolecular enhancement by π,π-interactions appears perfect to target nitrate. Chloride transporters are relevant to treat channelopathies, and nitrate sensors to monitor cellular signaling and cardiovascular diseases. A big impact on organocatalysis can be expected from the stabilization of anionic transition states on chiral π-acidic surfaces.

  17. Solvent-free liquid crystals and liquids based on genetically engineered supercharged polypeptides with high elasticity.

    Science.gov (United States)

    Liu, Kai; Pesce, Diego; Ma, Chao; Tuchband, Michael; Shuai, Min; Chen, Dong; Su, Juanjuan; Liu, Qing; Gerasimov, Jennifer Y; Kolbe, Anke; Zajaczkowski, Wojciech; Pisula, Wojciech; Müllen, Klaus; Clark, Noel A; Herrmann, Andreas

    2015-04-17

    A series of solvent-free elastin-like polypeptide liquid crystals and liquids are developed by electrostatic complexation of supercharged elastin-like polypeptides with surfactants. The smectic mesophases exhibit a high elasticity and the values can be easily tuned by varying the alkyl chain lengths of the surfactants or the lengths of the elastin-like polypeptides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Well-defined (co)polypeptides bearing pendant alkyne groups

    KAUST Repository

    Zhao, Wei

    2016-03-18

    A novel metal-free strategy, using hydrogen-bonding catalytic ring opening polymerization of acetylene-functionalized N-carboxy anhydrites of α-amino acids, was developed for the synthesis of well-defined polypeptides bearing pendant alkyne groups. This method provides an efficient way to synthesize novel alkyne-functionalized homopolypeptides (A) and copolypeptides, such as AB diblock (B: non-functionalized), ABA triblock and star-AB diblock, as well as linear and star random copolypeptides, precursors of a plethora complex macromolecular architectures by click chemistry.

  19. Ab initio study of alanine polypeptide chain twisting

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.

    2006-01-01

    We have investigated the potential energy surfaces for alanine chains consisting of three and six amino acids. For these molecules we have calculated potential energy surfaces as a function of the Ramachandran angles ph$ and psi, which are widely used for the characterization of the polypeptide...... and with the available experimental data extracted from the Protein Data Base. This comparison demonstrates a reasonable correspondence of the most prominent minima on the calculated potential energy surfaces to the experimentally measured angles phi and psi for alanine chains appearing in native proteins. We have also...

  20. Functional Modification of Thioether Groups in Peptides, Polypeptides, and Proteins.

    Science.gov (United States)

    Deming, Timothy J

    2017-03-15

    Recent developments in the modification of methionine and other thioether-containing residues in peptides, polypeptides, and proteins are reviewed. Properties and potential applications of the resulting functionalized products are also discussed. While much of this work is focused on natural Met residues, modifications at other side-chain residues have also emerged as new thioether-containing amino acids have been incorporated into peptidic materials. Functional modification of thioether-containing amino acids has many advantages and is a complementary methodology to the widely utilized methods for modification at cysteine residues.

  1. Reaction mechanisms in the radiolysis of peptides, polypeptides and proteins

    International Nuclear Information System (INIS)

    Garrison, W.M.

    1985-01-01

    The purpose of this review is to bring together and to correlate the wide variety of experimental studies that provide information on the reaction products and reaction mechanisms involved in the radiolysis of peptides, polypeptides and proteins (including chromosomal proteins) in both aqueous and solid-state systems. The comparative radiation chemistry of these systems is developed in terms of specific reactions of the peptide main-chain and the aliphatic, aromatic-unsaturated and sulfur-containing side-chains. Information obtained with the various experimental techniques of product analysis, competition kinetics, spin-trapping, pulse radiolysis and ESR spectroscopy is included. 147 refs

  2. Reaction mechanisms in the radiolysis of peptides, polypeptides and proteins

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, W.M.

    1985-01-01

    The purpose of this review is to bring together and to correlate the wide variety of experimental studies that provide information on the reaction products and reaction mechanisms involved in the radiolysis of peptides, polypeptides and proteins (including chromosomal proteins) in both aqueous and solid-state systems. The comparative radiation chemistry of these systems is developed in terms of specific reactions of the peptide main-chain and the aliphatic, aromatic-unsaturated and sulfur-containing side-chains. Information obtained with the various experimental techniques of product analysis, competition kinetics, spin-trapping, pulse radiolysis and ESR spectroscopy is included. 147 refs.

  3. Compositions comprising a polypeptide having cellulolytic enhancing activity and a bicycle compound and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Feng; Sweeney, Matthew; Quinlan, Jason

    2015-06-16

    The present invention relates to compositions comprising: a polypeptide having cellulolytic enhancing activity and a bicyclic compound. The present invention also relates to methods of using the compositions.

  4. Compositions comprising a polypeptide having cellulolytic enhancing activity and a quinone compound and uses thereof

    Science.gov (United States)

    Quinlan, Jason; Xu, Feng; Sweeney, Matthew

    2016-03-01

    The present invention relates to compositions comprising: a polypeptide having cellulolytic enhancing activity and a quinone compound. The present invention also relates to methods of using the compositions.

  5. Thermal aggregation behaviour of soy protein: characteristics of different polypeptides and sub-units.

    Science.gov (United States)

    He, Xiu-Ting; Yuan, De-Bao; Wang, Jin-Mei; Yang, Xiao-Quan

    2016-03-15

    Due to the differences in structure and composition of glycinin and β-conglycinin, they exhibit different characteristics during heat treatment. In present study, the thermal aggregation behaviour of glycinin, β-conglycinin and their isolated sub-units was investigated at pH 7.0. Acidic polypeptides, basic polypeptides, αα' and β sub-units of soy protein were denatured during the isolation process. The degree of aggregation of protein fractions after heat treatment was in the order: denatured basic polypeptides > native glycinin > denatured β sub-unit > native β-conglycinin > denatured acidic polypeptides > denatured αα' sub-units. Glycinin, β-conglycinin, acidic polypeptides and αα'/β sub-units exhibited different changing trends of surface hydrophobicity with increasing temperature. The αα' sub-units showed higher ability to suppress thermal aggregation of basic polypeptides than β sub-units during heat treatment. The β sub-units were shown to form soluble aggregates with glycinin after heating. The interaction mechanism of αα' and β sub-units heated with basic polypeptides was proposed. For the β sub-units-basic polypeptides mixed system, more hydrophobic chains were binding together and buried inside during heat treatment, which resulted in lower surface hydrophobicity. The αα' sub-units-basic polypeptides mixed system was considered to be a stable system with higher surface hydrophobicity after being heated. © 2015 Society of Chemical Industry.

  6. Molecular mechanisms of reduced glutathione transport: role of the MRP/CFTR/ABCC and OATP/SLC21A families of membrane proteins

    International Nuclear Information System (INIS)

    Ballatori, Nazzareno; Hammond, Christine L.; Cunningham, Jennifer B.; Krance, Suzanne M.; Marchan, Rosemarie

    2005-01-01

    The initial step in reduced glutathione (GSH) turnover in all mammalian cells is its transport across the plasma membrane into the extracellular space; however, the mechanisms of GSH transport are not clearly defined. GSH export is required for the delivery of its constituent amino acids to other tissues, detoxification of drugs, metals, and other reactive compounds of both endogenous and exogenous origin, protection against oxidant stress, and secretion of hepatic bile. Recent studies indicate that some members of the multidrug resistance-associated protein (MRP/CFTR or ABCC) family of ATP-binding cassette (ABC) proteins, as well as some members of the organic anion transporting polypeptide (OATP or SLC21A) family of transporters contribute to this process. In particular, five of the 12 members of the MRP/CFTR family appear to mediate GSH export from cells namely, MRP1, MRP2, MRP4, MRP5, and CFTR. Additionally, two members of the OATP family, rat Oatp1 and Oatp2, have been identified as GSH transporters. For the Oatp1 transporter, efflux of GSH may provide the driving force for the uptake of extracellular substrates. In humans, OATP-B and OATP8 do not appear to transport GSH; however, other members of this family have yet to be characterized in regards to GSH transport. In yeast, the ABC proteins Ycf1p and Bpt1p transport GSH from the cytosol into the vacuole, whereas Hgt1p mediates GSH uptake across the plasma membrane. Because transport is a key step in GSH homeostasis and is intimately linked to its biological functions, GSH export proteins are likely to modulate essential cellular functions

  7. Vasoactive intestinal polypeptide and other preprovasoactive intestinal polypeptide-derived peptides in the female and male genital tract: localization, biosynthesis, and functional and clinical significance

    DEFF Research Database (Denmark)

    Ottesen, B; Fahrenkrug, J

    1995-01-01

    in the control of erection. Vasoactive intestinal polypeptide has been suggested as a causative factor in some diseases of the genital organs (e.g., it may play a pathophysiologic role in male impotence and the peptide is currently used in the treatment of this condition). Vasoactive intestinal polypeptide may...... be important for control of the low resistance in the fetomaternal vascular bed and is therefore a putative factor involved in the development of preeclampsia. The therapeutic potential of vasoactive intestinal polypeptide and future agonists and antagonists will be revealed by ongoing and forthcoming studies....

  8. Sulfate transport in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Simonsen, K

    1988-01-01

    1. In short-circuited toad skin preparations exposed bilaterally to NaCl-Ringer's containing 1 mM SO2(-4), influx of sulfate was larger than efflux showing that the skin is capable of transporting sulfate actively in an inward direction. 2. This active transport was not abolished by substituting ...... (sulfate:bicarbonate exchange) and self-exchange diffusion take place. Irrespective of the mechanism of transport, sulfate is probably transported as a monovalent anion species....

  9. CDNA encoding a polypeptide including a hevein sequence

    Science.gov (United States)

    Raikhel, Natasha V.; Broekaert, Willem F.; Chua, Nam-Hai; Kush, Anil

    1995-03-21

    A cDNA clone (HEV1) encoding hevein was isolated via polymerase chain reaction (PCR) using mixed oligonucleotides corresponding to two regions of hevein as primers and a Hevea brasiliensis latex cDNA library as a template. HEV1 is 1018 nucleotides long and includes an open reading frame of 204 amino acids. The deduced amino acid sequence contains a putative signal sequence of 17 amino acid residues followed by a 187 amino acid polypeptide. The amino-terminal region (43 amino acids) is identical to hevein and shows homology to several chitin-binding proteins and to the amino-termini of wound-induced genes in potato and poplar. The carboxyl-terminal portion of the polypeptide (144 amino acids) is 74-79% homologous to the carboxyl-terminal region of wound-inducible genes of potato. Wounding, as well as application of the plant hormones abscisic acid and ethylene, resulted in accumulation of hevein transcripts in leaves, stems and latex, but not in roots, as shown by using the cDNA as a probe. A fusion protein was produced in E. coli from the protein of the present invention and maltose binding protein produced by the E. coli.

  10. Effects of snake venom polypeptides on central nervous system.

    Science.gov (United States)

    Osipov, Alexey; Utkin, Yuri

    2012-12-01

    The nervous system is a primary target for animal venoms as the impairment of its function results in the fast and efficient immobilization or death of a prey. There are numerous evidences about effects of crude snake venoms or isolated toxins on peripheral nervous system. However, the data on their interactions with the central nervous system (CNS) are not abundant, as the blood-brain barrier (BBB) impedes penetration of these compounds into brain. This updated review presents the data about interaction of snake venom polypeptides with CNS. Such data will be described according to three main modes of interactions: - Direct in vivo interaction of CNS with venom polypeptides either capable to penetrate BBB or injected into the brain. - In vitro interactions of cell or sub-cellular fractions of CNS with crude venoms or purified toxins. - Indirect effects of snake venoms or their components on functioning of CNS under different conditions. Although the venom components penetrating BBB are not numerous, they seem to be the most suitable candidates for the leads in drug design. The compounds with other modes of action are more abundant and better studied, but the lack of the data about their ability to penetrate BBB may substantially aggravate the potentials for their medical perspectives. Nevertheless, many such compounds are used for research of CNS in vitro. These investigations may give invaluable information for understanding the molecular basis of CNS diseases and thus lay the basis for targeted drug design. This aspect also will be outlined in the review.

  11. cDNA encoding a polypeptide including a hevein sequence

    Energy Technology Data Exchange (ETDEWEB)

    Raikhel, N.V.; Broekaert, W.F.; Chua, N.H.; Kush, A.

    2000-07-04

    A cDNA clone (HEV1) encoding hevein was isolated via polymerase chain reaction (PCR) using mixed oligonucleotides corresponding to two regions of hevein as primers and a Hevea brasiliensis latex cDNA library as a template. HEV1 is 1018 nucleotides long and includes an open reading frame of 204 amino acids. The deduced amino acid sequence contains a putative signal sequence of 17 amino acid residues followed by a 187 amino acid polypeptide. The amino-terminal region (43 amino acids) is identical to hevein and shows homology to several chitin-binding proteins and to the amino-termini of wound-induced genes in potato and poplar. The carboxyl-terminal portion of the polypeptide (144 amino acids) is 74--79% homologous to the carboxyl-terminal region of wound-inducible genes of potato. Wounding, as well as application of the plant hormones abscisic acid and ethylene, resulted in accumulation of hevein transcripts in leaves, stems and latex, but not in roots, as shown by using the cDNA as a probe. A fusion protein was produced in E. coli from the protein of the present invention and maltose binding protein produced by the E. coli.

  12. Importance of poly(ethylene oxide)-modification and chloride anion for the electron transfer reaction of cytochrome c in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

    International Nuclear Information System (INIS)

    Ohno, Hiroyuki; Suzuki, Chiiko; Fujita, Kyoko

    2006-01-01

    Horse heart cytochrome c (cyt c) was chemically modified with poly(ethylene oxide) (PEO) to dissolve it in room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim][TFSI]). The redox response of the modified cyt c, hereafter PEO-cyt c, was analyzed in [emim][TFSI]. PEO modification to the surface of cyt c, which exceeded 60% of the total mass of the PEO-cyt c, was an effective method to solubilize the cyt c. In spite of the high ion density and sufficient ionic conductivity of [emim][TFSI], no redox response of pure PEO-cyt c was detected. However, a reversible redox response of PEO-cyt c was observed after adding a simple electrolyte such as KCl to [emim][TFSI]. The redox response of PEO-cyt c was sensitive to the anion radius of the added salt, and the chloride anion was found to be the best anion species to produce a redox response of PEO-cyt c in [emim][TFSI]. However, above a certain salt concentration, the resulting increase in solution viscosity would suppress the redox reaction. The results strongly indicate that the chloride anions, because of their mobility in the polypeptide matrix, compensate the charge change of heme during the electron transfer reaction. Larger anions did not show such an effect due to sterical restrictions on the migration through the protein shell to the heme pocket of cyt c

  13. Two independent anion transport systems in rabbit mandibular salivary glands

    DEFF Research Database (Denmark)

    Novak, I; Young, J A

    1986-01-01

    in the following sequence: Br = greater than Cl greater than I = greater than NO3 greater than isethionate. Furosemide, 1.0 and 0.1 mmol/l, inhibited Cl-supported secretion by 97-99% and 70-78%, respectively. SITS, 0.1 mmol/l, had no effect and amiloride, 1.0 mmol/l, caused a 55-65% inhibition. Addition of SITS...... to amiloride-treated glands produced no further effect. In glands perfused with Cl-free solutions, but containing 25 mM HCO3, amiloride, 1.0 mmol/l, inhibited secretion by 95% and methazolamide, 0.1 mmol/l, by 55%. In glands perfused with solutions containing both HCO3 and Cl, furosemide had smaller effects...... stimulated secretion by about 30%, but when infused in addition to furosemide (0.1 mmol/l), it inhibited by about 20%. Amiloride (1.0 mmol/l) caused no inhibition. The results suggest that there are at least three distinct carriers in the rabbit mandibular gland. One is a furosemide-sensitive Na-coupled Cl...

  14. Evaluation of the endothelin receptor antagonists ambrisentan, bosentan, macitentan, and sitaxsentan as hepatobiliary transporter inhibitors and substrates in sandwich-cultured human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Eve-Irene Lepist

    Full Text Available Inhibition of the transporter-mediated hepatobiliary elimination of bile salts is a putative mechanism for liver toxicity observed with some endothelin receptor antagonists (ERAs.Sandwich-cultured human hepatocytes were used to study the hepatobiliary distribution and accumulation of exogenous taurocholate, ERAs and endogenous bile acids. The molecular mechanisms for findings in hepatocytes or clinical observations were further explored using either vesicular assays (efflux transporters or transfected cell-lines (uptake transporters. Inhibition constants (IC50 were measured for the human hepatobiliary transporters bile salt export pump (BSEP, sodium taurocholate cotransporting polypeptide (NTCP, multidrug resistance protein 2 (MRP2, P-glycoprotein (Pgp, breast cancer resistance protein (BCRP, organic anion-transporting polypeptide 1B1 (OATP1B1 and OATP1B3.The ERAs showed dose-dependent reductions in exogenous taurocholate cellular accumulation in human hepatocytes, with macitentan having the greatest effect. Consistent with their effects on bile acids, the ERAs inhibited bile transporters. IC50 values for OATP1B1 and OATP1B3 ranged from 2 µM for macitentan to 47 µM for ambrisentan. Macitentan and bosentan also inhibited NTCP with IC50 values of 10 and 36 µM, respectively. Similar to previously reported findings with sitaxsentan, BSEP inhibition was observed for bosentan and macitentan with IC50 values of 42 and 12 µM, respectively. In contrast, ambrisentan showed little or no inhibition of these transporters. Other transporters tested were weakly inhibited by the ERAs. Accumulation in hepatocytes was also a factor in the effects on bile transport. Macitentan demonstrated the greatest accumulation in human hepatocytes (∼100x followed by sitaxsentan (∼40x, bosentan (∼20x and ambrisentan (∼2x.Significant differences in the inhibition of hepatic transporters were observed between the evaluated ERAs in vitro. Macitentan had the highest

  15. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    International Nuclear Information System (INIS)

    Bowman-James, K.; Wilson, G.; Moyer, B. A.

    2004-01-01

    This project involves the design and synthesis of receptors for oxoanions of environmental importance, including emphasis on high level and low activity waste. Target anions have included primarily oxoanions and a study of the basic concepts behind selective binding of target anions. A primary target has been sulfate because of its deleterious influence on the vitrification of tank wastes

  16. Transport mechanisms of hepatic uptake and bile excretion in clinical hepatobiliary scintigraphy with 99mTc-N-pyridoxyl-5-methyltryptophan

    International Nuclear Information System (INIS)

    Kobayashi, Masato; Nakanishi, Takeo; Nishi, Kodai; Higaki, Yusuke; Okudaira, Hiroyuki; Ono, Masahiro; Tsujiuchi, Takafumi; Mizutani, Asuka; Nishii, Ryuichi; Tamai, Ikumi; Arano, Yasushi; Kawai, Keiichi

    2014-01-01

    Introduction: In clinical hepatobiliary scintigraphy, 99m Tc-N-pyridoxyl-5-methyltryptophan ( 99m Tc-PMT) is an effective radiotracer among the 99m Tc-pyridoxylaminates. However, the mechanisms of human hepatic uptake and bile excretion transport of 99m Tc-PMT have not been determined. We thus investigated the transport mechanisms of human hepatic uptake and bile excretion in hepatobiliary scintigraphy with 99m Tc-PMT. Methods: Four solute carrier (SLC) transporters involved in hepatic uptake were evaluated using human embryonic kidney (HEK) and HeLa cells with high expression of SLC transporters (organic anion transporting polypeptide (OATP)1B1, OATP1B3, OATP2B1, organic anion transporters (OAT)2 and organic cation transporters (OCT)1) after 5 min of 99m Tc-PMT incubation. Metabolic analysis of 99m Tc-PMT was performed using pooled human liver S9. Adenosine triphosphate (ATP)-binding cassette (ABC) transporters for bile excretion were examined using hepatic ABC transporter vesicles human expressing multiple drug resistance 1 (MDR1), multidrug resistance-associated protein 2 (MRP2), breast cancer resistance protein or bile salt export pump. 99m Tc-PMT was incubated for 1, 3 and 5 min with ATP or adenosine monophosphate and these vesicles. SPECT scans were performed in normal and Eisai hyperbilirubinemic (EHBR) model rats, deficient in Mrp2 transporters, without and with verapamil (rat Mdr1 and human MDR1 inhibitor) after intravenous injection of 99m Tc-PMT. Results: Uptake of 99m Tc-PMT in HEK293/OATP1B1 and HeLa/OATP1B3 was significantly higher than that in HEK293- and HeLa-mock cells. 99m Tc-PMT was not metabolized in the human liver S9. In vesicles with high expression of ABC transporters, uptake of MDR1 or MRP2 was significantly higher at all incubation times. Bile excretion of 99m Tc-PMT was also identified by comparison between normal and EHBR rats with and without verapamil on in-vivo imaging. Conclusions: Human hepatic uptake of 99m Tc-PMT was transferred

  17. Correction of the anion gap for albumin in order to detect occult tissue anions in shock.

    Science.gov (United States)

    Hatherill, M; Waggie, Z; Purves, L; Reynolds, L; Argent, A

    2002-12-01

    It is believed that hypoalbuminaemia confounds interpretation of the anion gap (AG) unless corrected for serum albumin in critically ill children with shock. To compare the ability of the AG and the albumin corrected anion gap (CAG) to detect the presence of occult tissue anions. Prospective observational study in children with shock in a 22 bed multidisciplinary paediatric intensive care unit of a university childrenrsquo;s hospital. Blood was sampled at admission and at 24 hours, for acid-base parameters, serum albumin, and electrolytes. Occult tissue anions (lactate + truly "unmeasured" anions) were calculated from the strong ion gap. The anion gap ((Na + K) - (Cl + bicarbonate)) was corrected for serum albumin using the equation of Figge: AG + (0.25 x (44 - albumin)). Occult tissue anions (TA) predicted by the anion gap were calculated by (anion gap - 15 mEq/l). Optimal cut off values of anion gap were compared by means of receiver operating characteristic (ROC) curves. Ninety three sets of data from 55 children (median age 7 months, median weight 4.9 kg) were analysed. Data are expressed as mean (SD), and mean bias (limits of agreement). The incidence of hypoalbuminaemia was 76% (n = 42/55). Mean serum albumin was 25 g/l (SD 8). Mean AG was 15.0 mEq/l (SD 6.1), compared to the CAG of 19.9 mEq/l (SD 6.6). Mean TA was 10.2 mmol/l (SD 6.3). The AG underestimated TA with mean bias 10.2 mmol/l (4.1-16.1), compared to the CAG, mean bias 5.3 mmol/l (0.4-10.2). A clinically significant increase of TA >5 mmol/l was present in 83% (n = 77/93) of samples, of which the AG detected 48% (n = 36/77), and the CAG 87% (n = 67/77). Post hoc ROC analysis revealed optimal cut off values for detection of TA >5 mmol/l to be AG >10 mEq/l, and CAG >15.5 mEq/l. Hypoalbuminaemia is common in critically ill children with shock, and is associated with a low observed anion gap that may fail to detect clinically significant amounts of lactate and other occult tissue anions. We suggest that

  18. Immunogenicity in dogs and protection against visceral leishmaniasis induced by a 14 kDa Leishmania infantum recombinant polypeptide

    Directory of Open Access Journals (Sweden)

    Claudia Abeijon

    2016-01-01

    Full Text Available In areas were human visceral leishmaniasis (VL is endemic, the domestic dog is the main parasite reservoir in the infectious cycle of Leishmania infantum. Development of prophylactic strategies to lower the parasite burden in dogs would reduce sand fly transmission thus lowering the incidence of zoonotic VL. Here we demonstrate that vaccination of dogs with a recombinant 14 kDa polypeptide of L. infantum nuclear transport factor 2 (Li-ntf2 mixed with adjuvant BpMPLA-SE resulted in the production of specific anti-Li-ntf2 IgG antibodies as well as IFN-γ release by the animals’ peripheral blood mononuclear cells stimulated with the antigen. In addition, immunization with this single and small 14 kDa polypeptide resulted in protracted progression of the infection of the animals after challenging with a high dose of virulent L. infantum. Five months after challenge the parasite load was lower in the bone marrow of immunized dogs compared to non-immunized animals. The antibody response to K39, a marker of active VL, at ten months after challenge was strong and significantly higher in the control dogs than in vaccinated animals. At the study termination vaccinated animals showed significantly more liver granulomas and lymphoid hyperplasia than non-vaccinated animals, which are both histological markers of resistance to infection. Together, these results indicate that the 14 kDa polypeptide is an attractive protective molecule that can be easily incorporated in a leishmanial polyprotein vaccine candidate to augment/complement the overall protective efficacy of the final product.

  19. Thymus Polypeptide Preparation Tactivin Restores Learning and Memory in Thymectomied Rats.

    Science.gov (United States)

    Novoseletskaya, A V; Kiseleva, N M; Zimina, I V; Bystrova, O V; Belova, O V; Inozemtsev, A N; Arion, V Ya; Sergienko, V I

    2015-09-01

    We studied the effects of tactivin and splenic polypeptides on learning and memory of thymectomized animals. In 3-week rats, thymectomy blocked active avoidance conditioning. Injections of tactivin (0.5 mg/kg) during 1 month after surgery restored learning capacity; splenic polypeptides were ineffective.

  20. Biosynthesis of the neural cell adhesion molecule: characterization of polypeptide C

    DEFF Research Database (Denmark)

    Nybroe, O; Albrechtsen, M; Dahlin, J

    1985-01-01

    The biosynthesis of the neural cell adhesion molecule (N-CAM) was studied in primary cultures of rat cerebral glial cells, cerebellar granule neurons, and skeletal muscle cells. The three cell types produced different N-CAM polypeptide patterns. Glial cells synthesized a 135,000 Mr polypeptide B...

  1. Competition between surface adsorption and folding of fibril-forming polypeptides

    NARCIS (Netherlands)

    Ni, R.; Kleijn, J.M.; Cohen Stuart, M.A.; Bolhuis, P.G.

    2015-01-01

    Self-assembly of polypeptides into fibrillar structures can be initiated by planar surfaces that interact favorably with certain residues. Using a coarse-grained model, we systematically studied the folding and adsorption behavior of a ß -roll forming polypeptide. We find that there are two

  2. Competition between surface adsorption and folding of fibril-forming polypeptides

    NARCIS (Netherlands)

    Ni, R.; de Kleijn, M.; Abeln, S.; Cohen Stuart, M.A.; Bolhuis, P.G.

    2015-01-01

    Self-assembly of polypeptides into fibrillar structures can be initiated by planar surfaces that interact favorably with certain residues. Using a coarse-grained model, we systematically studied the folding and adsorption behavior of a β-roll forming polypeptide. We find that there are two different

  3. Synthesis of peptide-grafted comb polypeptides via polymerisation of NCA-peptides.

    Science.gov (United States)

    Enomoto, Hiroshi; Nottelet, Benjamin; Halifa, Soultan Al; Enjalbal, Christine; Dupré, Mathieu; Tailhades, Julien; Coudane, Jean; Subra, Gilles; Martinez, Jean; Amblard, Muriel

    2013-01-14

    A straightforward synthesis of comb-polypeptides of repeated peptide sequences was developed. These polypeptides were obtained by ROP of defined NCA without any post-polymerization grafting. The key to this strategy relies on the preparation of pure NCA bearing a peptide sequence on its side chain, by an original solid supported methodology.

  4. Ontogeny of αA and αB crystallin polypeptides during Rana temporaria lens development

    NARCIS (Netherlands)

    Brahma, S.K.; McDevitt, D.S.; DeFize, L.H.K.

    The ontogeny and localization of αA and αB polypeptide chains of α-crystallin were investigated in the developing lens of Rana temporaria, an anuran amphibian, using the indirect immunofluorescence staining method with heterologous antibodies directed against these two polypeptides. αA and αB

  5. High-performance liquid chromatography of rat and mouse islet polypeptides

    DEFF Research Database (Denmark)

    Linde, S; Hansen, B; Welinder, B S

    1990-01-01

    supported its suspected identity as methionine sulphoxide insulin II. We have examined the formation of Met-O derivatives of insulin II, glucagon and pancreatic polypeptide during sample preparation (Sep-Pak and Speed-Vac concentrating). The oxidation of methionine residues was found to depend very much......-O derivatives is important for the quantitation of methionine-containing polypeptides....

  6. Self-assembly of α-helical polypeptides driven by complex coacervation.

    Science.gov (United States)

    Priftis, Dimitrios; Leon, Lorraine; Song, Ziyuan; Perry, Sarah L; Margossian, Khatcher O; Tropnikova, Anna; Cheng, Jianjun; Tirrell, Matthew

    2015-09-14

    Reported is the ability of α-helical polypeptides to self-assemble with oppositely-charged polypeptides to form liquid complexes while maintaining their α-helical secondary structure. Coupling the α-helical polypeptide to a neutral, hydrophilic polymer and subsequent complexation enables the formation of nanoscale coacervate-core micelles. While previous reports on polypeptide complexation demonstrated a critical dependence of the nature of the complex (liquid versus solid) on chirality, the α-helical structure of the positively charged polypeptide prevents the formation of β-sheets, which would otherwise drive the assembly into a solid state, thereby, enabling coacervate formation between two chiral components. The higher charge density of the assembly, a result of the folding of the α-helical polypeptide, provides enhanced resistance to salts known to inhibit polypeptide complexation. The unique combination of properties of these materials can enhance the known potential of fluid polypeptide complexes for delivery of biologically relevant molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Characterisation of the nascent polypeptide-associated complex in fission yeast

    DEFF Research Database (Denmark)

    Andersen, Katrine M; Semple, Colin A; Hartmann-Petersen, Rasmus

    2007-01-01

    The nascent polypeptide-associated complex (NAC) is an abundant and phylogenetically conserved protein complex. It is composed of two subunits and interacts with nascent polypeptide chains emerging from the ribosome. It has been proposed to protect the nascent chains from premature interaction...

  8. Competition between surface adsorption and folding of fibril-forming polypeptides

    NARCIS (Netherlands)

    Ni, R.; Kleijn, J.M.; Abeln, S.; Cohen Stuart, M.A.; Bolhuis, P.G.

    2015-01-01

    Self-assembly of polypeptides into fibrillar structures can be initiated by planar surfaces that interact favorably with certain residues. Using a coarse-grained model, we systematically studied the folding and adsorption behavior of a beta-roll forming polypeptide. We find that there are two

  9. Ring-Opening Polymerization of N-Carboxyanhydrides for Preparation of Polypeptides and Polypeptide-Based Hybrid Materials with Various Molecular Architectures

    KAUST Repository

    Pahovnik, David

    2015-09-01

    Different synthetic approaches utilizing ring-opening polymerization of N-carboxyanhydrides for preparation of polypeptide and polypeptide-based hybrid materials with various molecular architectures are described. An overview of polymerization mechanisms using conventional (various amines) as well as some recently developed initiators (hexamethyldisilazane, N-heterocyclic persistent carbenes, etc.) is presented, and their benefits and drawbacks for preparation of polypeptides with well-defined chain lengths and chain-end functionality are discussed. Recent examples from literature are used to illustrate different possibilities for synthesis of pure polypeptide materials with different molecular architectures bearing various functional groups, which are introduced either by modification of amino acids, before they are transformed into corresponding Ncarboxyanhydrides, or by post-polymerization modifications using protective groups and/or orthogonal functional groups. Different approaches for preparation of polypeptide-based hybrid materials are discussed as well using examples from recent literature. Syntheses of simple block copolymers or copolymers with more complex molecular architectures (graft and star copolymers) as well as modifications of nanoparticles and other surfaces with polypeptides are described.

  10. Absence of transepithelial anion exchange by rabbit OMCD: Evidence against reversal of cell polarity

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Matsuhiko; Schuster, V.L.; Stokes, J.B. (Univ. of Iowa College of Medicine, Iowa City (USA))

    1988-08-01

    In the rabbit cortical collecting duct (CCD), Cl tracer crosses the epithelium predominantly via an anion exchange system that operates in either a Cl-Cl or Cl-HCO{sub 3} exchange mode. In the present study, the authors used the {sup 36}Cl lumen-to-bath rate coefficient (K{sub Cl}, nm/s), a sensitive measurement of CCD transepithelial anion transport, to investigate the nature of Cl transport in the medullary collecting duct dissected from inner stripe, outer medulla (OMCD). The K{sub Cl} in OMCD perfused and bathed in HCO{sub 3}-Ringer solution was low and similar to that value observed in the CCD when anion exchange is inhibited and Cl permeates the epithelium by diffusion. To test the hypothesis that metabolic alkalosis could reverse the polarity of intercalated cells and thus induce an apical Cl-HCO{sub 3} exchanger in H{sup +}-secreting OMCD cells, they measured K{sub Cl} in OMCD from rabbits make alkalotic by deoxycorticosterone and furosemide. Although the base-line K{sub Cl} was slightly higher than in OMCD from control rabbits, the value was still far lower than the K{sub Cl} under comparable conditions in CCD. They conclude (1) Cl transport across the MCD by anion exchange is immeasurably low or nonexistent; (2) unlike the CCD, Cl transport in OMCD is not responsive to cAMP; and (3) metabolic alkalosis does not induce an apical anion exchanger in OMCD, i.e., does not cause epithelial polarity reversal.

  11. New borohydride anion B6H7-

    International Nuclear Information System (INIS)

    Kuznetsov, I.Yu.; Vinitskij, D.M.; Solntsev, K.A.

    1985-01-01

    The [Ni(Bipy) 3 ] (B 6 H 7 ) 2 , (Ph 4 P)B 6 H 7 , [Ni(Phen) 3 ](B 6 H 7 ) 2 crystals (where Bipy = bipyridine, Phen = phenathroline, Ph = phenyl) are obtained via the exchange reaction with a subsequent recrystallization from aqua-acetonic and acetonic solutions. The structure is studied of a new borohydride anion B 6 H 7 - possessing a four-valence bond unique for polyhedral borohydride anions. A triangular face of boride skeleton coordinating a hydrogen atom is considerably larger than other faces, and the electron density on this hydrogen atom is evidently much higher than at the end hydride hydrogen atoms. The trend of B 6 H 7 - anion to form statistically disordered structurs testifies to a rather slight effect of the seventh hydrogen atom position on the structure pattern of the ionic crystal lattice

  12. Photoemission from tin and lead cluster anions

    International Nuclear Information System (INIS)

    Gantefoer, G.; Gausa, M.; Meiwes-Broer, K.H.; Lutz, H.O.

    1989-01-01

    Photoelectrons from mass-identified jet-cooled tin and lead cluster anions (Sn n - , Pb n - ) are detached by ultraviolet laser light (hν=3.68 eV). The photoelectron energy spectra give the detachment energies of ground state cluster anions (electron affinities) as well as excitation energies of neutral clusters in the geometry of the anions. The energy spectra for Sn n - are dominated by flat thresholds with an n-dependence similar to that of other group IV clusters. In contrast, for Pb n - we find pronounced narrow lines close to threshold, generally followed by a 0.3-1.4 eV gap which indicates closed-shell behaviour of Pb n - for nearly all n. (orig.)

  13. Clinical acid-base pathophysiology: disorders of plasma anion gap.

    Science.gov (United States)

    Moe, Orson W; Fuster, Daniel

    2003-12-01

    The plasma anion gap is a frequently used parameter in the clinical diagnosis of a variety of conditions. The commonest application of the anion gap is to classify cases of metabolic acidosis into those that do and those that do not leave unmeasured anions in the plasma. While this algorithm is useful in streamlining the diagnostic process, it should not be used solely in this fashion. The anion gap measures the difference between the unmeasured anions and unmeasured cations and thus conveys much more information to the clinician than just quantifying anions of strong acids. In this chapter, the significance of the anion gap is emphasized and several examples are given to illustrate a more analytic approach to using the clinical anion gap; these include disorders of low anion gap, respiratory alkalosis and pyroglutamic acidosis.

  14. Inhibition of gastric inhibitory polypeptide signaling prevents obesity

    DEFF Research Database (Denmark)

    Miyawaki, Kazumasa; Yamada, Yuichiro; Ban, Nobuhiro

    2002-01-01

    Secretion of gastric inhibitory polypeptide (GIP), a duodenal hormone, is primarily induced by absorption of ingested fat. Here we describe a novel pathway of obesity promotion via GIP. Wild-type mice fed a high-fat diet exhibited both hypersecretion of GIP and extreme visceral and subcutaneous fat...... deposition with insulin resistance. In contrast, mice lacking the GIP receptor (Gipr(-/-)) fed a high-fat diet were clearly protected from both the obesity and the insulin resistance. Moreover, double-homozygous mice (Gipr(-/-), Lep(ob)/Lep(ob)) generated by crossbreeding Gipr(-/-) and obese ob/ob (Lep......(ob)/Lep(ob)) mice gained less weight and had lower adiposity than Lep(ob)/Lep(ob) mice. The Gipr(-/-) mice had a lower respiratory quotient and used fat as the preferred energy substrate, and were thus resistant to obesity. Therefore, GIP directly links overnutrition to obesity and it is a potential target for anti-obesity...

  15. Transport of N-acetyl-S-pentachloro-1,3-butadienylcysteine by rat renal cortex

    Energy Technology Data Exchange (ETDEWEB)

    Lock, E.A.; Odum, J.; Ormond, P.

    1986-05-01

    N-acetyl-S-pentachloro-1,3-butadienyl-L-cysteine (PCBD-NAC) is a postulated metabolite derived from glutathione conjugation of hexachloro-1,3-butadiene and is nephrotoxic in the rat. Because PCBD-NAC causes selective necrosis to the pars recta of the proximal tubule, and is an organic anion it might be expected to be transported by the renal organic anion transport system. Rat renal cortical slices were used to characterise the transport. /sup 14/C-PCBD-NAC uptake was temperature dependent and reduced by the metabolic inhibitors cyanide and iodoacetate. Probenecid and sulphinpyrazone, specific competitive inhibitors of the anion transport system, and dinitrophenol, a metabolic inhibitor as well as a competitive inhibitor of anion transport, reduced PCBD-NAC transport. Organic cations or uric acid transport inhibitors did not alter PCBD-NAC accumulation by the slices. These data are consistent with the transport of PCBD-NAC by the renal organic anion secretory system.

  16. Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca2+-ATPase

    Science.gov (United States)

    Tadini-Buoninsegni, Francesco; Moncelli, Maria Rosa; Peruzzi, Niccolò; Ninham, Barry W.; Dei, Luigi; Nostro, Pierandrea Lo

    2015-10-01

    The occurrence of Hofmeister (specific ion) effects in various membrane-related physiological processes is well documented. For example the effect of anions on the transport activity of the ion pump Na+, K+-ATPase has been investigated. Here we report on specific anion effects on the ATP-dependent Ca2+ translocation by the sarcoplasmic reticulum Ca2+-ATPase (SERCA). Current measurements following ATP concentration jumps on SERCA-containing vesicles adsorbed on solid supported membranes were carried out in the presence of different potassium salts. We found that monovalent anions strongly interfere with ATP-induced Ca2+ translocation by SERCA, according to their increasing chaotropicity in the Hofmeister series. On the contrary, a significant increase in Ca2+ translocation was observed in the presence of sulphate. We suggest that the anions can affect the conformational transition between the phosphorylated intermediates E1P and E2P of the SERCA cycle. In particular, the stabilization of the E1P conformation by chaotropic anions seems to be related to their adsorption at the enzyme/water and/or at the membrane/water interface, while the more kosmotropic species affect SERCA conformation and functionality by modifying the hydration layers of the enzyme.

  17. Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

    Science.gov (United States)

    Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

    2013-01-01

    Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H+-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

  18. Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

    Directory of Open Access Journals (Sweden)

    Lin-Tong Yang

    2013-01-01

    Full Text Available Approximately 30% of the world’s total land area and over 50% of the world’s potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a anion channels or transporters, (b internal concentrations of OA anions in plant tissues, (d temperature, (e root plasma membrane (PM H+-ATPase, (f magnesium (Mg, and (e phosphorus (P. Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed.

  19. High Vacuum Techniques for Anionic Polymerization

    KAUST Repository

    Ratkanthwar, Kedar

    2015-09-01

    Anionic polymerization high vacuum techniques (HVTs) are the most suitable for the preparation of polymer samples with well-defined complex macromolecular architectures. Though HVTs require glassblowing skill for designing and making polymerization reactor, it is the best way to avoid any termination of living polymers during the number of steps for the synthesis of polymers with complex structure. In this chapter, we describe the different polymerization reactors and HVTs for the purification of monomers, solvents, and other reagents for anionic polymerization as well as few model reactions for the synthesis of polymers with simple to complex structure.

  20. Organic superconductors with an incommensurate anion structure

    OpenAIRE

    Kawamoto, Tadashi; Takimiya, Kazuo

    2009-01-01

    Superconducting incommensurate organic composite crystals based on the methylenedithio-tetraselenafulvalene (MDT-TSF) series donors, where the energy band filling deviates from the usual 3/4-filled, are reviewed. The incommensurate anion potential reconstructs the Fermi surface for both (MDT-TSF)(AuI2)0.436 and (MDT-ST)(I3)0.417 neither by the fundamental anion periodicity q nor by 2q, but by 3q, where MDT-ST is 5H-2-(1,3-dithiol-2-ylidene)-1,3-diselena-4,6-dithiapentalene, and q is the recip...

  1. Recognition, Sensing and Separation of Anions

    Indian Academy of Sciences (India)

    Dr Pradyut Ghosh

    2016-11-05

    Nov 5, 2016 ... Arsenate Recognition in Aqueous Medium. Anion log K log Ka log Kb. HAsO4. 2-. 4.42. 4.35. -. H2PO4. -. 3.62. 3.62. 5.52. SO4. 2-. 3.48. 3.36. 4.73. CO3. 2-. 2.68. -. 4.04. Table 1. Association constant value of L in DMSO-d6/D2O (9:1, v/v) with different anion in DMSO-d6/D2O (1.1:1, v/v) at 298 K a: log K ...

  2. ANION GAP NO SANGUE VENOSO EM EQUINOS

    Directory of Open Access Journals (Sweden)

    Luís Carlos Ribeiro Fan

    1994-01-01

    Full Text Available RESUMO A influência do sangue venoso na determinação do anion gap foi estudada em 50 equinos adultos clinicamente sadios no município de Santa Maria, RS. Os resultados obtidos em mEq/1 foram: sódio 140 ± 2,0; potássio 4,2 ± 0,5; cloreto 102 ± 12 e bicarbonato 26,9 ± 2,0. Conclui-se que o sangue venoso pode substituir o arterial na determinação do anion gap em equinos.

  3. Genetic code redundancy and its influence on the encoded polypeptides

    Directory of Open Access Journals (Sweden)

    Paige S Spencer

    2012-04-01

    Full Text Available The genetic code is said to be redundant in that the same amino acid residue can be encoded by multiple, so-called synonymous, codons. If all properties of synonymous codons were entirely equivalent, one would expect that they would be equally distributed along protein coding sequences. However, many studies over the last three decades have demonstrated that their distribution is not entirely random. It has been postulated that certain codons may be translated by the ribosome faster than others and thus their non-random distribution dictates how fast the ribosome moves along particular segments of the mRNA. The reasons behind such segmental variability in the rates of protein synthesis, and thus polypeptide emergence from the ribosome, have been explored by theoretical and experimental approaches. Predictions of the relative rates at which particular codons are translated and their impact on the nascent chain have not arrived at unequivocal conclusions. This is probably due, at least in part, to variation in the basis for classification of codons as “fast” or “slow”, as well as variability in the number and types of genes and proteins analyzed. Recent methodological advances have allowed nucleotide-resolution studies of ribosome residency times in entire transcriptomes, which confirm the non-uniform movement of ribosomes along mRNAs and shed light on the actual determinants of rate control. Moreover, experiments have begun to emerge that systematically examine the influence of variations in ribosomal movement and the fate of the emerging polypeptide chain.

  4. GENETIC CODE REDUNDANCY AND ITS INFLUENCE ON THE ENCODED POLYPEPTIDES

    Directory of Open Access Journals (Sweden)

    Paige S. Spencer

    2012-04-01

    Full Text Available The genetic code is said to be redundant in that the same amino acid residue can be encoded by multiple, so-called synonymous, codons. If all properties of synonymous codons were entirely equivalent, one would expect that they would be equally distributed along protein coding sequences. However, many studies over the last three decades have demonstrated that their distribution is not entirely random. It has been postulated that certain codons may be translated by the ribosome faster than others and thus their non-random distribution dictates how fast the ribosome moves along particular segments of the mRNA. The reasons behind such segmental variability in the rates of protein synthesis, and thus polypeptide emergence from the ribosome, have been explored by theoretical and experimental approaches. Predictions of the relative rates at which particular codons are translated and their impact on the nascent chain have not arrived at unequivocal conclusions. This is probably due, at least in part, to variation in the basis for classification of codons as “fast” or “slow”, as well as variability in the number and types of genes and proteins analyzed. Recent methodological advances have allowed nucleotide-resolution studies of ribosome residency times in entire transcriptomes, which confirm the non-uniform movement of ribosomes along mRNAs and shed light on the actual determinants of rate control. Moreover, experiments have begun to emerge that systematically examine the influence of variations in ribosomal movement and the fate of the emerging polypeptide chain.

  5. Biosynthesis of human sialophorins and analysis of the polypeptide core

    International Nuclear Information System (INIS)

    Remold-O'Donnell, E.; Kenney, D.; Rosen, F.S.

    1987-01-01

    Biosynthesis was examined of sialophorin (formerly called gpL115) which is altered in the inherited immunodeficiency Wiskott-Aldrich syndrome. Sialophorin is greater than 50% carbohydrate, primarily O-linked units of sialic acid, galactose, and galactosamine. Pulse-labeling with [ 35 S]methionine and chase incubation established that sialophorin is synthesized in CEM lymphoblastoid cells as an Mr 62,000 precursor which is converted within 45 min to mature glycosylated sialophorin, a long-lived molecule. Experiments with tunicamycin and endoglycosidase H demonstrated that sialophorin contains N-linked carbohydrate (approximately two units per molecule) and is therefore an N,O-glycoprotein. Pulse-labeling of tunicamycin-treated CEM cells together with immunoprecipitation provided the means to isolate the [ 35 S]-methionine-labeled polypeptide core of sialophorin and determine its molecular weight (58,000). This datum allowed us to express the previously established composition on a per molecule basis and determine that sialophorin molecules contain approximately 520 amino acid residues and greater than or equal to 100 O-linked carbohydrate units. A recent study showed that various blood cells express sialophorin and that there are two molecular forms: lymphocyte/monocyte sialophorin and platelet/neutrophil sialophorin. Biosynthesis of the two forms was compared by using sialophorin of CEM cells and sialophorin of MOLT-4 cells (another lymphoblastoid line) as models for lymphocyte/monocyte sialophorin and platelet/neutrophil sialophorin, respectively. The time course of biosynthesis and the content of N units were found to be identical for the two sialophorin species. [ 35 S]Methionine-labeled polypeptide cores of CEM sialophorin and MOLT sialophorin were isolated and compared by electrophoresis, isoelectrofocusing, and a newly developed peptide mapping technique

  6. Cell cycle-dependent activity of the volume- and Ca2+-activated anion currents in Ehrlich lettre ascites cells

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjaer; Bergdahl, Andreas; Christophersen, Palle

    2007-01-01

    Recent evidence implicates the volume-regulated anion current (VRAC) and other anion currents in control or modulation of cell cycle progression; however, the precise involvement of anion channels in this process is unclear. Here, Cl- currents in Ehrlich Lettre Ascites (ELA) cells were monitored......+ in the pipette), was unaltered from G0 to G1, but decreased in early S phase. A novel high-affinity anion channel inhibitor, the acidic di-aryl-urea NS3728, which inhibited both VRAC and CaCC, attenuated ELA cell growth, suggesting a possible mechanistic link between cell cycle progression and cell cycle......-dependent changes in the capacity for conductive Cl- transport. It is suggested that in ELA cells, entrance into the S phase requires an increase in VRAC activity and/or an increased potential for regulatory volume decrease (RVD), and at the same time a decrease in CaCC magnitude....

  7. Mechanisms of fat-induced gastric inhibitory polypeptide/glucose-dependent insulinotropic polypeptide secretion from K cells.

    Science.gov (United States)

    Yamane, Shunsuke; Harada, Norio; Inagaki, Nobuya

    2016-04-01

    Gastric inhibitory polypeptide/glucose-dependent insulinotropic polypeptide (GIP) is one of the incretins, which are gastrointestinal hormones released in response to nutrient ingestion and potentiate glucose-stimulated insulin secretion. Single fat ingestion stimulates GIP secretion from enteroendocrine K cells; chronic high-fat diet (HFD) loading enhances GIP secretion and induces obesity in mice in a GIP-dependent manner. However, the mechanisms of GIP secretion from K cells in response to fat ingestion and GIP hypersecretion in HFD-induced obesity are not well understood. We generated GIP-green fluorescent protein knock-in (GIP (gfp/+)) mice, in which K cells are labeled by enhanced GIP-green fluorescent protein. Microarray analysis of isolated K cells from GIP (gfp/+) mice showed that both fatty acid-binding protein 5 and G protein-coupled receptor 120 are highly expressed in K cells. Single oral administration of fat resulted in significant reduction of GIP secretion in both fatty acid-binding protein 5- and G protein-coupled receptor 120-deficient mice, showing that fatty acid-binding protein 5 and G protein-coupled receptor 120 are involved in acute fat-induced GIP secretion. Furthermore, the transcriptional factor, regulatory factor X6 (Rfx6), is highly expressed in K cells. In vitro experiments using the mouse enteroendocrine cell line, STC-1, showed that GIP messenger ribonucleic acid levels are upregulated by Rfx6. Expression levels of Rfx6 messenger ribonucleic acid as well as that of GIP messenger ribonucleic acid were augmented in the K cells of HFD-induced obese mice, in which GIP content in the small intestine is increased compared with that in lean mice fed a control diet. These results suggest that Rfx6 is involved in hypersecretion of GIP in HFD-induced obese conditions by increasing GIP gene expression.

  8. Domed Silica Microcylinders Coated with Oleophilic Polypeptides and Their Behavior in Lyotropic Cholesteric Liquid Crystals of the Same Polypeptide.

    Science.gov (United States)

    Rosu, Cornelia; Jacobeen, Shane; Park, Katherine; Reichmanis, Elsa; Yunker, Peter; Russo, Paul S

    2016-12-13

    Liquid crystals can organize dispersed particles into useful and exotic structures. In the case of lyotropic cholesteric polypeptide liquid crystals, polypeptide-coated particles are appealing because the surface chemistry matches that of the polymeric mesogen, which permits a tighter focus on factors such as extended particle shape. The colloidal particles developed here consist of a magnetic and fluorescent cylindrically symmetric silica core with one rounded, almost hemispherical end. Functionalized with helical poly(γ-stearyl-l-glutamate) (PSLG), the particles were dispersed at different concentrations in cholesteric liquid crystals (ChLC) of the same polymer in tetrahydrofuran (THF). Defects introduced by the particles to the director field of the bulk PSLG/THF host led to a variety of phases. In fresh mixtures, the cholesteric mesophase of the PSLG matrix was distorted, as reflected in the absence of the characteristic fingerprint pattern. Over time, the fingerprint pattern returned, more quickly when the concentration of the PSLG-coated particles was low. At low particle concentration the particles were "guided" by the PSLG liquid crystal to organize into patterns similar to that of the re-formed bulk chiral nematic phase. When their concentration increased, the well-dispersed PSLG-coated particles seemed to map onto the distortions in the bulk host's local director field. The particles located near the glass vial-ChLC interfaces were stacked lengthwise into architectures with apparent two-dimensional hexagonal symmetry. The size of these "crystalline" structures increased with particle concentration. They displayed remarkable stability toward an external magnetic field; hydrophobic interactions between the PSLG polymers in the shell and those in the bulk LC matrix may be responsible. The results show that bio-inspired LCs can assemble suitable colloidal particles into soft crystalline structures.

  9. Synthesis of azaphenanthridines via anionic ring closure

    DEFF Research Database (Denmark)

    Hansen, Henriette Møller; Lysén, M.; Begtrup, M.

    2005-01-01

    A new and convergent synthesis of azaphenanthridines via an anionic ring closure is reported. Ortho-lithiation/in situ borylation of cyanopyridines produces the corresponding cyanopyridylboronic esters, which undergo a Suzuki-Miyaura cross-coupling to give the key intermediates. Addition of lithium...

  10. Interstellar dehydrogenated PAH anions: vibrational spectra

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter; Gour, Nand Kishor

    2018-03-01

    Interstellar polycyclic aromatic hydrocarbon (PAH) molecules exist in diverse forms depending on the local physical environment. Formation of ionized PAHs (anions and cations) is favourable in the extreme conditions of the interstellar medium (ISM). Besides in their pure form, PAHs are also likely to exist in substituted forms; for example, PAHs with functional groups, dehydrogenated PAHs etc. A dehydrogenated PAH molecule might subsequently form fullerenes in the ISM as a result of ongoing chemical processes. This work presents a density functional theory (DFT) calculation on dehydrogenated PAH anions to explore the infrared emission spectra of these molecules and discuss any possible contribution towards observed IR features in the ISM. The results suggest that dehydrogenated PAH anions might be significantly contributing to the 3.3 μm region. Spectroscopic features unique to dehydrogenated PAH anions are highlighted that may be used for their possible identification in the ISM. A comparison has also been made to see the size effect on spectra of these PAHs.

  11. Ejectisins: tough and tiny polypeptides are a major component of cryptophycean ejectisomes.

    Science.gov (United States)

    Ammermann, Silke; Schneider, Tristan; Westermann, Martin; Hillebrand, Helmut; Rhiel, Erhard

    2013-04-01

    Fragments of discharged ejectisomes were isolated from two Cryptomonas and a Chroomonas species by detergent treatment followed by Percoll density gradient centrifugation. The fragments withstand high concentrated detergent solutions, reducing agents and freeze-thawing. Disintegration was achieved in 6 M guanidine hydrochloride. Reassembly into long, filamentous, ejectisome-like structures occurred after dialysis. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the polypeptide patterns of isolated ejectisome fragments and of reconstituted ejectisome-like structures were dominated by polypeptides with relative molecular weights of approximately 6 kDa. The polypeptides were not glycosylated and did not cross-react with antisera directed against recombinant Reb polypeptides which constitute the R-bodies of Caedibacter taeniospiralis. A polyclonal antiserum directed against reconstituted, ejectisome-like filaments cross-reacted with the 6-kDa polypeptides and immunolabeled extruded ejectisome filaments. Twenty amino acid residues, obtained by N-terminal amino acid sequence analysis, matched to polypeptide sequences deduced from cDNA sequences of the cryptophyte Guillardia theta. The term "ejectisins" is introduced for the 6-kDa polypeptides which represent a major component of cryptophycean ejectisomes.

  12. Peptides and polypeptides as scaffolds for optoelectronics and biomaterials applications

    Science.gov (United States)

    Charati, Manoj B.

    Peptides and polypeptides are emerging as a new class of biomaterials due to their unique structural, physiochemical, mechanical, and biological properties. The development of peptide and protein-based biomaterials is driven by the convergence of convenient techniques for peptide/protein engineering and its importance in applications as smart biomaterials. The thesis is divided in two parts; the first part highlights the importance of incorporation of non-natural amino acids into peptides and proteins. In particular, incorporation on p-bromophenylalanine in short alpha-helical peptide templates to control the association of chromophores is discussed. In the second part, design of a multi-component, biocompatible polypeptide with superior elasticity is discussed. Part 1. Novel peptide templates to control association of chromophores. Tailor made peptide and protein materials have many versatile applications, as both conformation and functional group position can be controlled. Such control may have intriguing applications in the development of hybrid materials for electroactive applications. A critical need in fabricating devices from organic semiconducting materials is to achieve control over the conformation and distance between two conjugated chains. Controlling chromophore spacing and orientation with required precision over nanometer length scale poses a greater challenge. Here we propose a peptide based template to control the alignment of the methylstilbene and Oxa-PPV chromophores with desired orientations and spacing. The hybrid peptides were characterized via CD, exciton coupled CD, 1H NMR and photoluminescence experiments. It is observed that slight change in the orientation of molecules has pronounced effect on the photo-physical behavior of the molecules. Characterization of the hybrid peptides via circular dichroism (CD) confirmed the helical character of the designed peptides and indicated that inclusion of non-natural amino acids has significant

  13. Anatomical localization and some pharmacological effects of vasoactive intestinal polypeptide in human and monkey corpus cavernosum.

    Science.gov (United States)

    Steers, W D; McConnell, J; Benson, G S

    1984-11-01

    Vasoactive intestinal polypeptide is hypothesized to be a nonadrenergic, noncholinergic neurotransmitter important in the physiology of penile erection. To further explore this concept, anatomical localization of vasoactive intestinal polypeptide, in vitro muscle bath studies and in vivo injection experiments were undertaken in the monkey and man. Using immunohistochemical techniques vasoactive intestinal polypeptide was localized at the light microscopic level to nerves within the monkey and human penis. Ultrastructurally, a modified peroxidase-antiperoxidase technique was used to identify large vasoactive intestinal polypeptide-positive vesicles within peptidergic and cholinergic varicosities. In the in vitro muscle bath, the addition of 10(-7) M vasoactive intestinal polypeptide did not alter the baseline tension of strips of monkey and human corpus cavernosum. During contraction produced by norepinephrine stimulation, however, vasoactive intestinal polypeptide (10(-7) M) caused relaxation of the monkey (41 +/- 18 per cent, no. = 8) and human (23 +/- 8 per cent, no. = 5) corpus cavernosum. Intracorporal injection of vasoactive intestinal polypeptide (0.75 X 10(-9) to 3.75 X 10(-9) moles/kg.) had no effect on the monkey penis. Administration of vasoactive intestinal polypeptide (1.25 X 10(-9) to 2.5 X 10(-9) moles/kg.) into the internal iliac artery of the monkey, while having no effect on the flaccid penis, caused detumescence of the erect penis obtained by cavernous nerve stimulation (2-5 V, 40 Hz, 2 msec.). Although vasoactive intestinal polypeptide can be found within the nerves of the penis, its apparent in vitro and in vivo effects raise further questions concerning the role of this peptide in penile erection.

  14. Effect of sequence on the ionization behavior of a series of amphiphilic polypeptides.

    Science.gov (United States)

    Fowler, Michael; Siddique, Bushra; Duhamel, Jean

    2013-04-09

    The behavior of five polypeptides made of hydrophilic and pH-responsive aspartic acid (Asp) and hydrophobic phenylalanine (Phe), which had been prepared by stitching together short well-defined sequences of Asp and Phe, was studied as a function of pH. The effect of pH on these polypeptides referred to as (Asp3Phe1)n, (Asp2Phe1)n, (Asp1Phe1)n, (Asp1Phe2)n, and (Asp1Phe3)n varied dramatically depending on their constituting sequence. The more hydrophobic polypeptides (Asp1Phe2)n and (Asp1Phe3)n behaved as if the Asp's were isolated from each other and showed an apparent pKa (pKa(app)) that remained constant with level of ionization (α = [Asp(-)]/[Asp]total) and equaled 5.4 and 6.4, respectively. The more hydrophilic polypeptides (Asp3Phe1)n and (Asp2Phe1)n behaved like weak polyacids showing a linear increase in pKa(app) with increasing α. The pKa(app) of (Asp1Phe1)n showed a trend as a function of α intermediate between the Asp-rich and Phe-rich polypeptides, behaving as if the Asp's were isolated at low α values (0.35). The effect that α, and thus the charge density of the polypeptides, had on the collapse and aggregation of the polypeptides was characterized by conducting static light scattering and fluorescence measurements. Static light scattering measurements demonstrated that all polypeptides precipitated and aggregated in solution at a critical charge density of 0.2. Fluorescence measurements with pyrene indicated that this behavior was due to the formation of Phe aggregates in water. Together, these experiments provide a complete description of how pH affects the behavior of a series of unique amphiphilic polypeptides designed with a well-defined sequence.

  15. Experimental Detection of the Pentazole Anion, N5(-)

    National Research Council Canada - National Science Library

    Vij, Ashwani

    2002-01-01

    .... Whereas at low collision voltages the para-phenoxypentazole anion undergoes stepwise N2 elimination generating the corresponding azide and nitrene, at high collision voltages the N5(-) anion is formed...

  16. The Research on the Impact of Maca Polypeptide on Sport Fatigue.

    Science.gov (United States)

    Miao, Hua

    2015-01-01

    In order to study the effect of maca polypeptide on sport fatigue, this paper selected 40 male mice, and they were randomly divided into group A, B, C and D. group A, B and C were fed food with different concentrations of maca polypeptide, and group D was control group. After two weeks of feeding, measured physiological indexes of mice, including blood glucose, urea nitrogen and creatinine. At last gived the experimental results, as well as the analysis. Experimental results show that maca polypeptide can improve the ability of anti-fatigue mice, and in a certain concentration range, the higher the concentration, the better the resistance to fatigue.

  17. The polymerization of amino acid adenylates on sodium-montmorillonite with preadsorbed polypeptides

    Science.gov (United States)

    Paecht-Horowitz, Mella; Eirich, Frederick R.

    1988-01-01

    The spontaneous polymerization of amino acid adenylates on Na-montmorillonite in dilute, neutral suspension, after polypeptides were adsorbed on the clay, is studied. It is found that the degrees of polymerization of the oligopeptides and polypeptides obtained is dependent on the amounts of polypeptides that were preadsorbed. It is concluded that a catalytic activity may derive from c-spacings that offer adsorption sites for the reagent amino acid adenylate within the peripheral recesses of irregularly stacked clay platelets by bringing the anhydride bonds and neutral amino groups into favorable reaction distances.

  18. Processes for the production of hydroxycinnamic acids using polypeptides having tyrosine ammonia lyase activity

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention generally relates to the field of biotechnology as it applies to the production of hydroxycinnamic acids using polypeptides having tyrosine ammonia lyase activity. More particularly, the present invention pertains to polypeptides having tyrosine ammonia lyase activity and high...... substrate specificity towards tyrosine, which makes them particularly suitable in the production of p-coumaric acid and other hydroxycinnamic acids. The present invention thus provides processes for the production of p-coumaric acid and other hydroxycinnamic acids employing these polypeptides as well...

  19. Modelling the Effects of Competing Anions on Fluoride Removal by ...

    African Journals Online (AJOL)

    NICOLAAS

    ... the physico-chemical properties of anions and their interaction with the adsorbent surface.16. Properties of anions such as the solubility, ionic radius, hydration energy and bulk diffusion coefficient are of great importance for the selective adsorption of anions.17 In our earlier study the equilibrium and thermodynamics of ...

  20. Inhibitory Effects of Green Tea and (-)-Epigallocatechin Gallate on Transport by OATP1B1, OATP1B3, OCT1, OCT2, MATE1, MATE2-K and P-Glycoprotein.

    Science.gov (United States)

    Knop, Jana; Misaka, Shingen; Singer, Katrin; Hoier, Eva; Müller, Fabian; Glaeser, Hartmut; König, Jörg; Fromm, Martin F

    2015-01-01

    Green tea catechins inhibit the function of organic anion transporting polypeptides (OATPs) that mediate the uptake of a diverse group of drugs and endogenous compounds into cells. The present study was aimed at investigating the effect of green tea and its most abundant catechin epigallocatechin gallate (EGCG) on the transport activity of several drug transporters expressed in enterocytes, hepatocytes and renal proximal tubular cells such as OATPs, organic cation transporters (OCTs), multidrug and toxin extrusion proteins (MATEs), and P-glycoprotein (P-gp). Uptake of the typical substrates metformin for OCTs and MATEs and bromosulphophthalein (BSP) and atorvastatin for OATPs was measured in the absence and presence of a commercially available green tea and EGCG. Transcellular transport of digoxin, a typical substrate of P-gp, was measured over 4 hours in the absence and presence of green tea or EGCG in Caco-2 cell monolayers. OCT1-, OCT2-, MATE1- and MATE2-K-mediated metformin uptake was significantly reduced in the presence of green tea and EGCG (P green tea [IC50 2.6% (v/v) and 0.39% (v/v), respectively]. Green tea also inhibited OATP1B1- and OATP1B3-mediated atorvastatin net uptake with IC50 values of 1.9% (v/v) and 1.0% (v/v), respectively. Basolateral to apical transport of digoxin was significantly decreased in the presence of green tea and EGCG. These findings indicate that green tea and EGCG inhibit multiple drug transporters in vitro. Further studies are necessary to investigate the effects of green tea on prototoypical substrates of these transporters in humans, in particular on substrates of hepatic uptake transporters (e.g. statins) as well as on P-glycoprotein substrates.

  1. Characterization of SLCO5A1/OATP5A1, a solute carrier transport protein with non-classical function.

    Directory of Open Access Journals (Sweden)

    Katrin Sebastian

    Full Text Available Organic anion transporting polypeptides (OATP/SLCO have been identified to mediate the uptake of a broad range of mainly amphipathic molecules. Human OATP5A1 was found to be expressed in the epithelium of many cancerous and non-cancerous tissues throughout the body but protein characterization and functional analysis have not yet been performed. This study focused on the biochemical characterization of OATP5A1 using Xenopus laevis oocytes and Flp-In T-REx-HeLa cells providing evidence regarding a possible OATP5A1 function. SLCO5A1 is highly expressed in mature dendritic cells compared to immature dendritic cells (∼6.5-fold and SLCO5A1 expression correlates with the differentiation status of primary blood cells. A core- and complex- N-glycosylated polypeptide monomer of ∼105 kDa and ∼130 kDa could be localized in intracellular membranes and on the plasma membrane, respectively. Inducible expression of SLCO5A1 in HeLa cells led to an inhibitory effect of ∼20% after 96 h on cell proliferation. Gene expression profiling with these cells identified immunologically relevant genes (e.g. CCL20 and genes implicated in developmental processes (e.g. TGM2. A single nucleotide polymorphism leading to the exchange of amino acid 33 (L→F revealed no differences regarding protein expression and function. In conclusion, we provide evidence that OATP5A1 might be a non-classical OATP family member which is involved in biological processes that require the reorganization of the cell shape, such as differentiation and migration.

  2. Ionic Resistance and Permselectivity Tradeoffs in Anion Exchange Membranes

    KAUST Repository

    Geise, Geoffrey M.

    2013-10-23

    Salinity gradient energy technologies, such as reverse electrodialysis (RED) and capacitive mixing based on Donnan potential (Capmix CDP), could help address the global need for noncarbon-based energy. Anion exchange membranes (AEMs) are a key component in these systems, and improved AEMs are needed in order to optimize and extend salinity gradient energy technologies. We measured ionic resistance and permselectivity properties of quaternary ammonium-functionalized AEMs based on poly(sulfone) and poly(phenylene oxide) polymer backbones and developed structure-property relationships between the transport properties and the water content and fixed charge concentration of the membranes. Ion transport and ion exclusion properties depend on the volume fraction of water in the polymer membrane, and the chemical nature of the polymer itself can influence fine-tuning of the transport properties to obtain membranes with other useful properties, such as chemical and dimensional stability. The ionic resistance of the AEMs considered in this study decreased by more than 3 orders of magnitude (i.e., from 3900 to 1.6 Ω m) and the permselectivity decreased by 6% (i.e., from 0.91 to 0.85) as the volume fraction of water in the polymer was varied by a factor of 3.8 (i.e., from 0.1 to 0.38). Water content was used to rationalize a tradeoff relationship between the permselectivity and ionic resistance of these AEMs whereby polymers with higher water content tend to have lower ionic resistance and lower permselectivity. The correlation of ion transport properties with water volume fraction and fixed charge concentration is discussed with emphasis on the importance of considering water volume fraction when interpreting ion transport data. © 2013 American Chemical Society.

  3. Intestinal mucosa is a target tissue for pancreatic polypeptide

    International Nuclear Information System (INIS)

    Gilbert, W.R.; Kramer, J.L.; Frank, B.H.; Gingerich, R.L.

    1986-01-01

    Studies were carried out to identify mammalian tissues capable of specifically binding mammalian pancreatic polypeptide (PP). Bovine PP (bPP) radiolabeled with 125 I was purified by HPLC to yield [ 125 I]iodo-(Tyr-27) bPP. The label was injected into three pairs of fasted littermate dogs and allowed to circulate for 5 min. One of the dogs was a control which received an excess of unlabeled porcine PP to provide competition for receptor binding. Unbound bPP was removed by perfusion with Krebs-Ringer bicarbonate and the tissue fixed in situ with Karnovsky's fixative. Tissue samples from various organs were removed, weighed, and counted. The entire gastrointestinal tract demonstrated high levels of 125 I after injection of the labeled peptide. The duodenum, jejunum, ileum, and colon were the only tissues to exhibit specific binding of bPP. These tissues (mucosal and muscle layers) from experimental animals exhibited 31-76% higher binding than the corresponding tissues from the control animals. Sections of the gastrointestinal tract were scraped to separate the mucosal layer from the underlying muscle layer. The mucosal layer of the duodenum, jejunum, and ileum exhibited 145-162% increases in binding compared to the control animals. The muscle layer of these tissues demonstrated no significant increase. These findings demonstrate that mucosal layer of the small intestine is a target tissue for mammalian PP

  4. TRAP display: a high-speed selection method for the generation of functional polypeptides.

    Science.gov (United States)

    Ishizawa, Takahiro; Kawakami, Takashi; Reid, Patrick C; Murakami, Hiroshi

    2013-04-10

    Here, we describe a novel method that enables high-speed in vitro selection of functional peptides, peptidomimetics, and proteins via a simple procedure. We first developed a new cell-free translation system, the TRAP system (transcription-translation coupled with association of puromycin linker), which automatically produces a polypeptide library through a series of sequential reactions: transcription, association of puromycin-DNA linker, translation, and conjugation between the nascent polypeptide and puromycin-DNA linker. We then applied the TRAP system for the selection of macrocyclic peptides against human serum albumin. Six rounds of selection using TRAP display were performed in approximately 14 h, yielding macrocyclic peptides with nanomolar affinity to their target protein. Because TRAP display enables high-speed selection of functional polypeptides, it will facilitate the generation of various polypeptides that are useful for biological and therapeutic applications.

  5. Variants of polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, Matt; Wogulis, Mark

    2017-11-14

    The present invention relates to polypeptide having cellulolytic enhancing activity variants. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.

  6. Papain-Catalyzed Chemoenzymatic Synthesis of Telechelic Polypeptides Using Bis(Leucine Ethyl Ester) Initiator.

    Science.gov (United States)

    Tsuchiya, Kousuke; Numata, Keiji

    2016-07-01

    In order to construct unique polypeptide architectures, a novel telechelic-type initiator with two leucine ethyl ester units is designed for chemoenzymatic polymerization. Glycine or alanine ethyl ester is chemoenzymatically polymerized using papain in the presence of the initiator, and the propagation occurs at each leucine ethyl ester unit to produce the telechelic polypeptide. The formation of the telechelic polypeptides is confirmed by (1) H NMR and MALDI-TOF mass spectroscopies. It is revealed by AFM observation that long nanofibrils are formed from the telechelic polyalanine, whereas a conventional linear polyalanine with a similar degree of polymerization shows granule-like structures. The telechelic polyglycine and polyalanine show the crystalline structures of Polyglycine II and antiparallel β-sheet, respectively. It is demonstrated that this method to synthesize telechelic-type polypeptides potentially opens up a pathway to construct novel hierarchical structures by self-assembly. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Star-Shaped Polypeptides: Synthesis and Opportunities for Delivery of Therapeutics.

    Science.gov (United States)

    Byrne, Mark; Murphy, Robert; Kapetanakis, Antonios; Ramsey, Joanne; Cryan, Sally-Ann; Heise, Andreas

    2015-09-17

    Significant advances in the synthesis of polypeptides by N-carboxyanhydride (NCA) polymerisation over the last decade have enabled the design of advanced polypeptide architectures such as star-shaped polypeptides. These materials combine the functionality offered by amino acids with the flexibility of creating stable nanoparticles with adjustable cargo space for therapeutic delivery. This review highlights recent advances in the synthesis of star polypeptides by NCA polymerisation followed by a critical review of the applications of this class of polymer in the delivery of therapeutic agents. This includes examples of traditional small-molecule drugs as well as the emerging class of biologics such as genetic therapeutics (gene delivery). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Zwitterionic states in gas-phase polypeptide ions revealed by 157-nm ultra-violet photodissociation

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Silivra, Oleg A; Zubarev, Roman A

    2006-01-01

    within polypeptide clusters. Collision-activated dissociation (CAD) of decarboxylated cations localizes the position of deprotonation. Fragment abundances can be used for the semiquantitative assessment of the branching ratio of deprotonation among different acidic sites, however, the mechanism...

  9. Induction of protein body formation in plant leaves by elastin-like polypeptide fusions

    Directory of Open Access Journals (Sweden)

    Joensuu Jussi J

    2009-08-01

    Full Text Available Abstract Background Elastin-like polypeptides are synthetic biopolymers composed of a repeating pentapeptide 'VPGXG' sequence that are valuable for the simple non-chromatographic purification of recombinant proteins. In addition, elastin-like polypeptide fusions have been shown to enhance the accumulation of a range of different recombinant proteins in plants, thus addressing the major limitation of plant-based expression systems, which is a low production yield. This study's main objectives were to determine the general utility of elastin-like polypeptide protein fusions in various intracellular compartments and to elucidate elastin-like polypeptide's mechanism of action for increasing recombinant protein accumulation in the endoplasmic reticulum of plants. Results The effect of elastin-like polypeptide fusions on the accumulation of green fluorescent protein targeted to the cytoplasm, chloroplasts, apoplast, and endoplasmic reticulum was evaluated. The endoplasmic reticulum was the only intracellular compartment in which an elastin-like polypeptide tag was shown to significantly enhance recombinant protein accumulation. Interestingly, endoplasmic reticulum-targeted elastin-like polypeptide fusions induced the formation of a novel type of protein body, which may be responsible for elastin-like polypeptide's positive effect on recombinant protein accumulation by excluding the heterologous protein from normal physiological turnover. Although expressed in the leaves of plants, these novel protein bodies appeared similar in size and morphology to the prolamin-based protein bodies naturally found in plant seeds. The elastin-like polypeptide-induced protein bodies were highly mobile organelles, exhibiting various dynamic patterns of movement throughout the cells, which were dependent on intact actin microfilaments and a functional actomyosin motility system. Conclusion An endoplasmic reticulum-targeted elastin-like polypeptide fusion approach

  10. Interactions between anions and soil constituents

    International Nuclear Information System (INIS)

    Bolt, G.H.; Haan, F.A.M. de

    1965-01-01

    Clay mineral crystals are characterized by a non-isotropic structure, in which a pattern is recognized. It is known that the planar sides are negatively charged (as a result of the isomorphic replacement of Si 4+ by Al 3+ and/or Al 3+ by Mg 2+ ). Under certain conditions the exposed alumina groups at the edges are charged positively. The different types of interaction between ions and clay crystals may be listed as follows: (a) Cations: positive adsorption on planar side (electrostatic interaction modified by -- non-electrostatic -- specific factors); and possibly negative adsorption at positively charged edges (electrostatic effect). (b) Anions: negative adsorption (exclusion) on planar side (electrostatic effect); and positive adsorption on the edges -- in part electrostatic, if edge positively charged; furthermore chemisorption of certain anions, as e.g. PO 4 , SiO 4

  11. An intracellular anion channel critical for pigmentation.

    Science.gov (United States)

    Bellono, Nicholas W; Escobar, Iliana E; Lefkovith, Ariel J; Marks, Michael S; Oancea, Elena

    2014-12-16

    Intracellular ion channels are essential regulators of organellar and cellular function, yet the molecular identity and physiological role of many of these channels remains elusive. In particular, no ion channel has been characterized in melanosomes, organelles that produce and store the major mammalian pigment melanin. Defects in melanosome function cause albinism, characterized by vision and pigmentation deficits, impaired retinal development, and increased susceptibility to skin and eye cancers. The most common form of albinism is caused by mutations in oculocutaneous albinism II (OCA2), a melanosome-specific transmembrane protein with unknown function. Here we used direct patch-clamp of skin and eye melanosomes to identify a novel chloride-selective anion conductance mediated by OCA2 and required for melanin production. Expression of OCA2 increases organelle pH, suggesting that the chloride channel might regulate melanin synthesis by modulating melanosome pH. Thus, a melanosomal anion channel that requires OCA2 is essential for skin and eye pigmentation.

  12. Rubella virion polypeptides. Characterization by polyacrylamide gel electrophoresis, isoelectric focusing and peptide mapping

    Energy Technology Data Exchange (ETDEWEB)

    Ho-Terry, L.; Cohen, A. (University Coll. Hospital Medical School, London (UK))

    1982-01-01

    Four polypeptides with molecular weights of 55K, 47K, 45K, and 33K have been resolved by polyacrylamide gel electrophoresis of immune precipitated rubella virus. The 47K and 45K components have similar peptide maps but different isoelectric points so that the same polypeptide may exist in more than one charged form. The 55K and 45K components have similar isoelectric points but different peptide maps showing that similarity of isoelectric point is not evidence of identity.

  13. Vasoactive Intestinal Polypeptide and Muscarinic Receptors: Supersensitivity Induced by Long-Term Atropine Treatment

    Science.gov (United States)

    Hedlund, Britta; Abens, Janis; Bartfai, Tamas

    1983-04-01

    Long-term treatment of rats with atropine induced large increases in the numbers of muscarinic receptors and receptors for vasoactive intestinal polypeptide in the salivary glands. Since receptors for vasoactive intestinal polypeptide coexist with muscarinic receptors on the same neurons in this preparation, the results suggest that a drug that alters the sensitivity of one receptor may also affect the sensitivity of the receptor for a costored transmitter and in this way contribute to the therapeutic or side effects of the drug.

  14. Glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide: new advances

    DEFF Research Database (Denmark)

    Asmar, Meena; Holst, Jens Juul

    2010-01-01

    This article highlights recent advances in our understanding of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) physiology and their various sites of action beyond the incretin effect.......This article highlights recent advances in our understanding of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) physiology and their various sites of action beyond the incretin effect....

  15. Metal ion-dependent, reversible, protein filament formation by designed beta-roll polypeptides

    Science.gov (United States)

    Scotter, Andrew J; Guo, Meng; Tomczak, Melanie M; Daley, Margaret E; Campbell, Robert L; Oko, Richard J; Bateman, David A; Chakrabartty, Avijit; Sykes, Brian D; Davies, Peter L

    2007-01-01

    Background A right-handed, calcium-dependent β-roll structure found in secreted proteases and repeat-in-toxin proteins was used as a template for the design of minimal, soluble, monomeric polypeptides that would fold in the presence of Ca2+. Two polypeptides were synthesised to contain two and four metal-binding sites, respectively, and exploit stacked tryptophan pairs to stabilise the fold and report on the conformational state of the polypeptide. Results Initial analysis of the two polypeptides in the presence of calcium suggested the polypeptides were disordered. The addition of lanthanum to these peptides caused aggregation. Upon further study by right angle light scattering and electron microscopy, the aggregates were identified as ordered protein filaments that required lanthanum to polymerize. These filaments could be disassembled by the addition of a chelating agent. A simple head-to-tail model is proposed for filament formation that explains the metal ion-dependency. The model is supported by the capping of one of the polypeptides with biotin, which disrupts filament formation and provides the ability to control the average length of the filaments. Conclusion Metal ion-dependent, reversible protein filament formation is demonstrated for two designed polypeptides. The polypeptides form filaments that are approximately 3 nm in diameter and several hundred nm in length. They are not amyloid-like in nature as demonstrated by their behaviour in the presence of congo red and thioflavin T. A capping strategy allows for the control of filament length and for potential applications including the "decoration" of a protein filament with various functional moieties. PMID:17908326

  16. Cholecystokinin, secretin, pancreatic polypeptide in relation to gallbladder dynamics and gastrointestinal interdigestive motility

    DEFF Research Database (Denmark)

    Qvist, N; Oster-Jørgensen, E; Rasmussen, L

    1990-01-01

    Using a combined technique of hepatobiliary scintigraphy and gastrointestinal motility recordings, the changes in blood concentrations of cholecystokinin (CCK), secretin and pancreatic polypeptide (PP) were studied in relation to gastrointestinal motility and gallbladder dynamics in the interdige......Using a combined technique of hepatobiliary scintigraphy and gastrointestinal motility recordings, the changes in blood concentrations of cholecystokinin (CCK), secretin and pancreatic polypeptide (PP) were studied in relation to gastrointestinal motility and gallbladder dynamics...

  17. Correlation between ovarian growth, vitellogenin titer, and yolk polypeptide pattern in the haemolymph of Calliphora vicina

    DEFF Research Database (Denmark)

    Sørensen, Ilona Kryspin; Jensen, P. V.

    1982-01-01

    During the first egg maturation cycle ofCalliphora vicina changes in the vitellogenin titer and yolk polypeptide pattern of the haemolymph are correlated with the intensity of follicular growth, and the rate of yolk deposition.......During the first egg maturation cycle ofCalliphora vicina changes in the vitellogenin titer and yolk polypeptide pattern of the haemolymph are correlated with the intensity of follicular growth, and the rate of yolk deposition....

  18. Politseiuuringud kooskõlastamisele / Liivia Anion

    Index Scriptorium Estoniae

    Anion, Liivia

    2003-01-01

    1. aprillil 2003. a. moodustatud uurimistööde kooskõlastamise komisjoni tegevuse eesmärk on saada ülevaade kõrgkoolides õppivate töötajate poolt politseis korraldatavatest uurimustest, kasutada saadud infot politsei kasuks ja vältida teenistujate tööd segavate uurimuste tegemist. Komisjoni liige Liivia Anion teeb ülevaate komisjoni otsustuspädevuse valdkondadest ja töökorraldusest

  19. Sequence anatomy of mitochondrial anion carriers

    Czech Academy of Sciences Publication Activity Database

    Ježek, Petr; Ježek, Jan

    2003-01-01

    Roč. 534, 1-3 (2003), s. 15-25 ISSN 0014-5793 R&D Projects: GA AV ČR IAA5011106; GA ČR GA301/02/1215; GA MŠk ME 389 Institutional research plan: CEZ:AV0Z5011922 Keywords : mitochondrial anion carriers * carrier genomics * bioinformatics Subject RIV: CE - Biochemistry Impact factor: 3.609, year: 2003

  20. Molecular basis of claudin-17 anion selectivity.

    Science.gov (United States)

    Conrad, Marcel P; Piontek, Jörg; Günzel, Dorothee; Fromm, Michael; Krug, Susanne M

    2016-01-01

    Claudin-17 is a paracellular channel-forming tight junction protein. Unlike the cation channels claudin-2 and -15, claudin-17 forms a distinct anion-selective channel. Aim of this study was to determine the molecular basis of channel formation and charge selectivity of this protein. To achieve this, residues located in the extracellular loops (ECL) 1 and 2 of claudin-17 were substituted, preferably those whose charges differed in claudin-17 and in claudin-2 or -15. The respective mutants were stably expressed in MDCK C7 cells and their ability to form charge-selective channels was analyzed by measuring ion permeabilities and transepithelial electrical resistance. The functional data were combined with homology modeling of the claudin-17 protomer using the structure of claudin-15 as template. In ECL1, K65, R31, E48, and E44 were found to be stronger involved in Cldn17 channel function than the clustered R45, R56, R59, and R61. For K65, not only charge but also stereochemical properties were crucial for formation of the anion-selective channel. In ECL2, both Y149 and H154 were found to contribute to constitution of the anion channel in a distinct manner. In conclusion, we provide insight into the molecular mechanism of the formation of charge- and size-selective paracellular ion channels. In detail, we propose a hydrophilic furrow in the claudin-17 protomer spanning from a gap between the ends of TM2 and TM3 along R31, E48, and Y67 to a gap between K65 and S68 lining the anion channel.

  1. Revisiting the Anionic Polymerization of Methyl Ethacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Kennemur, Justin G. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee FL 32306-4390 USA; Bates, Frank S. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis MN 55455-0431 USA; Hillmyer, Marc A. [Department of Chemistry, University of Minnesota, Minneapolis MN 55455-0431 USA

    2017-09-26

    Synthesis of poly(methyl ethacrylate), (PMEA), in tetrahydrofuran at -78 °C using anionic polymerization techniques results in high molar mass (>30 kg mol-1), low dispersity (1.3), and high conversion (>81%). The molar masses of a series of samples are consistent with values anticipated by the monomer-to-initiator ratio and conversion. These results represent a significant improvement to earlier reported attempts to prepare PMEA using anionic methods. Successful diblock polymerization of polystyrene-block-PMEA, (PS-PMEA), and poly(4-tert-butylstyrene)-block-PMEA, (PtBS-PMEA), is achieved through sequential anionic polymerization techniques with dispersities as low as 1.06 and segment molar fractions close to those targeted. Broad principal scattering peaks observed by small-angle X-ray scattering (SAXS) for symmetric PS-PMEA at relatively high molar mass (39 kg mol-1) suggests an effective interaction parameter (χeff) that is smaller than for PS-block-poly(methyl methacrylate). On the other hand, PtBS-PMEA block polymers form a well-ordered morphology based on SAXS measurements and is attributable to the more hydrophobic PtBS segment. These results confirm the viability of PMEA as a new constituent in the expanding suite of polymers suitable for preparing nanostructured block polymers.

  2. New Kunitz-Type HCRG Polypeptides from the Sea Anemone Heteractis crispa

    Directory of Open Access Journals (Sweden)

    Irina Gladkikh

    2015-09-01

    Full Text Available Sea anemones are a rich source of Kunitz-type polypeptides that possess not only protease inhibitor activity, but also Kv channels toxicity, analgesic, antihistamine, and anti-inflammatory activities. Two Kunitz-type inhibitors belonging to a new Heteractis crispa RG (HCRG polypeptide subfamily have been isolated from the sea anemone Heteractis crispa. The amino acid sequences of HCRG1 and HCRG2 identified using the Edman degradation method share up to 95% of their identity with the representatives of the HCGS polypeptide multigene subfamily derived from H. crispa cDNA. Polypeptides are characterized by positively charged Arg at the N-terminus as well as P1 Lys residue at their canonical binding loop, identical to those of bovine pancreatic trypsin inhibitor (BPTI. These polypeptides are shown by our current evidence to be more potent inhibitors of trypsin than the known representatives of the HCGS subfamily with P1Thr. The kinetic and thermodynamic characteristics of the intermolecular interactions between inhibitors and serine proteases were determined by the surface plasmon resonance (SPR method. Residues functionally important for polypeptide binding to trypsin were revealed using molecular modeling methods. Furthermore, HCRG1 and HCRG2 possess anti-inflammatory activity, reducing tumor necrosis factor-α (TNF-α and interleukin 6 (IL-6 secretions, as well as proIL-1β expression in lipopolysaccharide (LPS-activated macrophages. However, there was no effect on nitric oxide (NO generation.

  3. New Kunitz-Type HCRG Polypeptides from the Sea Anemone Heteractis crispa.

    Science.gov (United States)

    Gladkikh, Irina; Monastyrnaya, Margarita; Zelepuga, Elena; Sintsova, Oksana; Tabakmakher, Valentin; Gnedenko, Oksana; Ivanov, Alexis; Hua, Kuo-Feng; Kozlovskaya, Emma

    2015-09-24

    Sea anemones are a rich source of Kunitz-type polypeptides that possess not only protease inhibitor activity, but also Kv channels toxicity, analgesic, antihistamine, and anti-inflammatory activities. Two Kunitz-type inhibitors belonging to a new Heteractis crispa RG (HCRG) polypeptide subfamily have been isolated from the sea anemone Heteractis crispa. The amino acid sequences of HCRG1 and HCRG2 identified using the Edman degradation method share up to 95% of their identity with the representatives of the HCGS polypeptide multigene subfamily derived from H. crispa cDNA. Polypeptides are characterized by positively charged Arg at the N-terminus as well as P1 Lys residue at their canonical binding loop, identical to those of bovine pancreatic trypsin inhibitor (BPTI). These polypeptides are shown by our current evidence to be more potent inhibitors of trypsin than the known representatives of the HCGS subfamily with P1Thr. The kinetic and thermodynamic characteristics of the intermolecular interactions between inhibitors and serine proteases were determined by the surface plasmon resonance (SPR) method. Residues functionally important for polypeptide binding to trypsin were revealed using molecular modeling methods. Furthermore, HCRG1 and HCRG2 possess anti-inflammatory activity, reducing tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) secretions, as well as proIL-1β expression in lipopolysaccharide (LPS)-activated macrophages. However, there was no effect on nitric oxide (NO) generation.

  4. Effects of side group functionality and molecular weight on the activity of synthetic antimicrobial polypeptides.

    Science.gov (United States)

    Engler, Amanda C; Shukla, Anita; Puranam, Sravanthi; Buss, Hilda G; Jreige, Nina; Hammond, Paula T

    2011-05-09

    The rapid emergence of antibiotic-resistant bacteria along with increasing difficulty in biofilm treatment has caused an immediate need for the development of new classes of antimicrobial therapeutics. We have developed a library of antimicrobial polypeptides, prepared by the ring-opening polymerization of γ-propargyl-L-glutamate N-carboxyanhydride and the alkyne-azide cycloaddition click reaction, which mimic the favorable characteristics of naturally occurring antimicrobial peptides (AmPs). AmPs are known not to cause drug resistance as well as prevent bacteria attachment on surfaces. The ease and scale of synthesis of the antimicrobial polypeptides developed here are significantly improved over the traditional Merrifield synthetic peptide approaches needed for naturally occurring antimicrobial peptides and avoids the unique challenges of biosynthetic pathways. The polypeptides range in length from 30 to 140 repeat units and can have varied side group functionality, including primary, secondary, tertiary, and quaternary amines with hydrocarbon side chains ranging from 1 to 12 carbons long. Overall, we find these polypeptides to exhibit broad-spectrum activity against both Gram positive and Gram negative bacteria, namely, S. aureus and E. coli , while having very low hemolytic activity. Many of the polypeptides can also be used as surface coatings to prevent bacterial attachment. The polypeptide library developed in this work addresses the need for effective biocompatible therapeutics for drug delivery and medical device coatings.

  5. Algorithm to design inhibitors using stereochemically mixed l,d polypeptides: Validation against HIV protease.

    Science.gov (United States)

    Gupta, Pooja; Durani, Susheel

    2015-11-01

    Polypeptides have potential to be designed as drugs or inhibitors against the desired targets. In polypeptides, every chiral α-amino acid has enantiomeric structural possibility to become l or d amino acids and can be used as design monomer. Among the various possibilities, use of stereochemistry as a design tool has potential to determine both functional specificity and metabolic stability of the designed polypeptides. The polypeptides with mixed l,d amino acids are a class of peptidomimitics, an attractive drug like molecules and also less susceptible to proteolytic activities. Therefore in this study, a three step algorithm is proposed to design the polypeptides against desired drug targets. For this, all possible configurational isomers of mixed l,d polyleucine (Ac-Leu8-NHMe) structure were randomly modeled with simulated annealing molecular dynamics and the resultant library of discrete folds were scored against HIV protease as a model target. The best scored folds of mixed l,d structures were inverse optimized for sequences in situ and the resultant sequences as inhibitors were validated for conformational integrity using molecular dynamics. This study presents and validates an algorithm to design polypeptides of mixed l,d structures as drugs/inhibitors by inverse fitting them as molecular ligands against desired target. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Stimuli responsive synthetic polypeptides derived from N-carboxyanhydride (NCA) polymerisation.

    Science.gov (United States)

    Huang, Jin; Heise, Andreas

    2013-09-07

    The progress in NCA polymerisation combined with advanced orthogonal functionalization techniques as well as the integration with other controlled polymerisation techniques significantly widened the scope of polypeptide building blocks in a variety of material designs. Well-defined synthetic stimuli-responsive polypeptides ("smart" polypeptides) with incorporated different functionalities have been extensively explored over the past decades. Their significant potential lies in the fact that they combine natural and synthetic elements both contributing to their properties. These novel materials have potential applications in biomedicine and biotechnology including tissue engineering, drug delivery and biodiagnostics. Responsive polypeptides are capable of undergoing conformational changes and phase transition accompanied by variations in the chemical and physical changes of the polypeptides in response to an external stimulus such as biologically relevant species (i.e. biomolecules), the environment (i.e. temperature, pH), irradiation with light or exposure to a magnetic field. In this review, the recent developments including synthetic strategies and applications of synthetic stimuli-responsive homo- and block polypeptides are reviewed.

  7. Ion-selective electrode and anion gap range: What should the anion gap be?

    Science.gov (United States)

    Sadjadi, Seyed-Ali; Manalo, Rendell; Jaipaul, Navin; McMillan, James

    2013-01-01

    Using flame photometry technique in the 1970s, the normal value of anion gap (AG) was determined to be 12 ± 4 meq/L. However, with introduction of the autoanalyzers using an ion-selective electrode (ISE), the anion gap value has fallen to lower levels. A retrospective study of US veterans from a single medical center was performed to determine the value of the anion gap in subjects with normal renal function and normal serum albumin and in patients with lactic acidosis and end-stage renal disease on dialysis. In 409 patients with an estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) body surface area and serum albumin ≥4 g/dL, the mean AG was 7.2 ± 2 (range 3-11) meq/L. In 299 patients with lactic acidosis (lactate level ≥4 meq/L) and 68 patients with endstage renal disease on dialysis, the mean AG was 12.5 meq/L and 12.4 meq/L, respectively. A value anion gap and a possible clue to drug intoxication and paraproteinemic disorders. With the advent of ISE for measurement of analytes, the value of the anion gap has fallen. Physicians need to be aware of the normal AG value in their respective institutions, and laboratories need to have an established value for AG based on the type of instrument they are using.

  8. A predictive model for anion exclusion in compacted Na-montmorillonite

    International Nuclear Information System (INIS)

    Tournassat, C.; Appelo, C.A.J.

    2010-01-01

    Document available in extended abstract form only. In current concepts for geological disposal of radioactive wastes, anions represent potentially the highest uncertainty in the performance assessment. Anions are weakly sorbed or even repelled from the negative clay surface constitutive of buffer (montmorillonite in bentonite) or natural (e.g. Callovo-Oxfordian argillite) material in the multi-barrier systems, and thus, are transported without retardation through only part of the pore space of the clay. The reduced accessibility of the pore space in clay is termed anion exclusion. The inner structure of bentonite with its different porosities is of paramount importance for understanding how transport (by diffusion) depends on compaction and solution composition. Anion exclusion is a well known process in soil science. Its quantification and modelling in dilute clay suspension has been a matter of much research in the 50-60's. Reanalysis of these data led to the conclusion that the Modified Gouy-Chapman (MGC) theory is able to predict fairly well the experimental data in NaCl ionic background up to ∼0.01 mol L -1 when coupled to the consideration of montmorillonite quasi-crystal formation in the suspension. Despite the available knowledge on anion exclusion in dilute systems using MGC theory, there has been little effort to extend this type of approach to compacted systems. The present study aims at obtaining a prediction method for anion exclusion in bentonite with montmorillonite as the major mineral, spanning the whole range from dilute suspension to compacted material. The model considers the specific properties of montmorillonite, with water is distributed over diverse porosities with different characteristics, viz. free (bulk) pore water, a charge neutral solution, diffuse double layer water, containing an excess of cations that compensate a fraction of the clay charge, and interlayer water, which is part of the montmorillonite structure. A model

  9. Binary polypeptide system for permanent and oriented protein immobilization

    Directory of Open Access Journals (Sweden)

    Bailes Julian

    2010-05-01

    Full Text Available Abstract Background Many techniques in molecular biology, clinical diagnostics and biotechnology rely on binary affinity tags. The existing tags are based on either small molecules (e.g., biotin/streptavidin or glutathione/GST or peptide tags (FLAG, Myc, HA, Strep-tag and His-tag. Among these, the biotin-streptavidin system is most popular due to the nearly irreversible interaction of biotin with the tetrameric protein, streptavidin. The major drawback of the stable biotin-streptavidin system, however, is that neither of the two tags can be added to a protein of interest via recombinant means (except for the Strep-tag case leading to the requirement for chemical coupling. Results Here we report a new immobilization system which utilizes two monomeric polypeptides which self-assemble to produce non-covalent yet nearly irreversible complex which is stable in strong detergents, chaotropic agents, as well as in acids and alkali. Our system is based on the core region of the tetra-helical bundle known as the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex. This irreversible protein attachment system (IPAS uses either a shortened syntaxin helix and fused SNAP25-synaptobrevin or a fused syntaxin-synaptobrevin and SNAP25 allowing a two-component system suitable for recombinant protein tagging, capture and immobilization. We also show that IPAS is suitable for use with traditional beads and chromatography, planar surfaces and Biacore, gold nanoparticles and for protein-protein interaction in solution. Conclusions IPAS offers an alternative to chemical cross-linking, streptavidin-biotin system and to traditional peptide affinity tags and can be used for a wide range of applications in nanotechnology and molecular sciences.

  10. Binary polypeptide system for permanent and oriented protein immobilization.

    Science.gov (United States)

    Ferrari, Enrico; Darios, Frédéric; Zhang, Fan; Niranjan, Dhevahi; Bailes, Julian; Soloviev, Mikhail; Davletov, Bazbek

    2010-05-12

    Many techniques in molecular biology, clinical diagnostics and biotechnology rely on binary affinity tags. The existing tags are based on either small molecules (e.g., biotin/streptavidin or glutathione/GST) or peptide tags (FLAG, Myc, HA, Strep-tag and His-tag). Among these, the biotin-streptavidin system is most popular due to the nearly irreversible interaction of biotin with the tetrameric protein, streptavidin. The major drawback of the stable biotin-streptavidin system, however, is that neither of the two tags can be added to a protein of interest via recombinant means (except for the Strep-tag case) leading to the requirement for chemical coupling. Here we report a new immobilization system which utilizes two monomeric polypeptides which self-assemble to produce non-covalent yet nearly irreversible complex which is stable in strong detergents, chaotropic agents, as well as in acids and alkali. Our system is based on the core region of the tetra-helical bundle known as the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex. This irreversible protein attachment system (IPAS) uses either a shortened syntaxin helix and fused SNAP25-synaptobrevin or a fused syntaxin-synaptobrevin and SNAP25 allowing a two-component system suitable for recombinant protein tagging, capture and immobilization. We also show that IPAS is suitable for use with traditional beads and chromatography, planar surfaces and Biacore, gold nanoparticles and for protein-protein interaction in solution. IPAS offers an alternative to chemical cross-linking, streptavidin-biotin system and to traditional peptide affinity tags and can be used for a wide range of applications in nanotechnology and molecular sciences.

  11. Explaining Ethnic Variability of Transporter Substrate Pharmacokinetics in Healthy Asian and Caucasian Subjects with Allele Frequencies of OATP1B1 and BCRP: A Mechanistic Modeling Analysis.

    Science.gov (United States)

    Li, Rui; Barton, Hugh A

    2018-04-01

    Ethnic variability in the pharmacokinetics of organic anion transporting polypeptide (OATP) 1B1 substrates has been observed, but its basis is unclear. A previous study hypothesizes that, without applying an intrinsic ethnic variability in transporter activity, allele frequencies of transporters cannot explain observed ethnic variability in pharmacokinetics. However, this hypothesis contradicts the data collected from compounds that are OATP1B1 substrates but not breast cancer resistance protein (BCRP) substrates. The objective of this study is to evaluate a hypothesis that is physiologically reasonable and more consistent with clinical observations. We evaluated if allele frequencies of two transporters (OATP1B1 and BCRP) are key contributors to ethnic variability. In this hypothesis, the same genotype leads to the same activity independent of ethnicity, in contrast to the previous hypothesis of intrinsic ethnic variability in OATP1B1 activity. As a validation, we perform mechanistic pharmacokinetic modeling for SLCO1B1 (encoding OATP1B1) and ABCG2 (encoding BCRP) genotyped pharmacokinetic data from 18 clinical studies with healthy Caucasian and/or Asian subjects. Simulations based on the current hypothesis reasonably describe SLCO1B1 and ABCG2 genotyped pharmacokinetic time course data for five transporter substrates (atorvastatin, pitavastatin, pravastatin, repaglinide, and rosuvastatin) in Caucasian and Asian populations. This hypothesis covers the observations that can (e.g., ethnic differences in rosuvastatin pharmacokinetics) or cannot (e.g., lack of differences for pitavastatin pharmacokinetics) be explained by the previous hypothesis. It helps to characterize sources of ethnic variability and provides a foundation for predicting ethnic variability in transporter substrate pharmacokinetics.

  12. Probenecid Treatment Enhances Retinal and Brain Delivery of N-4-Benzoylaminophenylsulfonylglycine, An Anionic Aldose Reductase Inhibitor

    Science.gov (United States)

    Sunkara, Gangadhar; Ayalasomayajula, Surya P.; DeRuiter, Jack; Kompella, Uday B.

    2009-01-01

    Anion efflux transporters are expected to minimize target tissue delivery of N-[4-(benzoylaminophenyl)sulfonyl]glycine (BAPSG), a novel carboxylic acid aldose reductase inhibitor, which exists as a monocarboxylate anion at physiological conditions. Therefore, the objective of this study was to determine whether BAPSG delivery to various eye tissues including the retina and the brain can be enhanced by probenecid, a competitive inhibitor of anion transporters. To determine the influence of probenecid on eye and brain distribution of BAPSG, probenecid was administered intraperitoneally (120 mg/kg body weight; i.p.) 20 minutes prior to BAPSG (50 mg/kg; i.p.) administration. Drug disposition in various eye tissues including the retina and the brain was determined at 15 min, 1, 2 and 4 hr after BAPSG dose in male Sprauge-Dawley rats. To determine whether probenecid alters plasma clearance of BAPSG, influence of probenecid (120 mg/kg; i.p.) on the plasma pharmacokinetics of intravenously administered BAPSG (15 mg/kg) was studied as well. Finally, the effect of probenecid co-administration on the ocular tissue distribution of BAPSG was assessed in rabbits following topical (eye drop) administration. Following pretreatment with probenecid in the rat study, retinal delivery at 1 hr was increased by about 11 fold (2580 vs 244 ng/gm; pprobenecid pretreatment, significant BAPSG levels were detectable in the brain (45 ± 20 ng/gm) at 1 hr, unlike controls where the drug was not detectable. Plasma concentrations, plasma elimination half-life, and total body clearance of intravenously administered BAPSG were not altered by i.p. probenecid pretreatment. In the topical dosing study, a significant decline in BAPSG delivery was observed in the iris-ciliary body but no significant changes were observed in other tissues of the anterior segment of the eye including tears. Thus, inhibition of anion transporters is a useful approach to elevate retinal and brain delivery of BAPSG. PMID

  13. Ion-selective electrode and anion gap range: What should the anion gap be?

    OpenAIRE

    Sadjadi,; Manalo,Rendell; Jaipaul,Navin; McMillan,James

    2013-01-01

    Seyed-Ali Sadjadi, Rendell Manalo, Navin Jaipaul, James McMillan Jerry L Pettis Memorial Veterans Medical Center, Loma Linda University School of Medicine, Loma Linda, CA, USA Background: Using flame photometry technique in the 1970s, the normal value of anion gap (AG) was determined to be 12 ± 4 meq/L. However, with introduction of the autoanalyzers using an ion-selective electrode (ISE), the anion gap value has fallen to lower levels. Methods: A retrospective study of US veteran...

  14. Self-assembled micelles of amphiphilic poly(L-phenylalanine)-b-poly(L-serine) polypeptides for tumor-targeted delivery.

    Science.gov (United States)

    Zhao, Ziming; Wang, Yu; Han, Jin; Wang, Keli; Yang, Dan; Yang, Yihua; Du, Qian; Song, Yuanjian; Yin, Xiaoxing

    2014-01-01

    The aim of this work was to design, synthesize, and characterize self-assembled micelles based on polypeptides as a potential antitumor drug carrier. Amphiphilic poly(L-phenylalanine)-b-poly(L-serine) (PFS) polypeptides were obtained through the polymerization of N-carboxyanhydride. As a novel hydrophilic segment, poly(L-serine) was utilized to enhance tumor targeting due to a large demand of tumors for serine. PFS could self-assemble into micelles with an average diameter of 110-240 nm and a slightly negative charge. PFS polypeptides adopted random coil in pH 7.4 phosphate-buffered saline and could partly transform to α-helix induced by trifluoroethanol. PFS micelles with a low critical micelle concentration of 4.0 μg mL(-1) were stable in pH 5-9 buffers and serum albumin solution. PFS micelles had a loading capacity of 3.8% for coumarin-6 and exhibited a sustained drug release. Coumarin-6 loaded rhodamine B isothiocyanate-labeled PFS micelles were incubated with Huh-7 tumor cells to study the correlation between drugs and carriers during endocytosis. The uptake of drugs was consistent with the micelles, illustrating that the intracellular transport of drugs highly depended on the micelles. PFS micelles diffused in whole cytoplasm while coumarin-6 assumed localized distribution, suggesting that the micelles could release the loaded drugs in particular areas. The internalization mechanism of PFS micelles was involved with clathrin-mediated endocytosis and macropinocytosis. Excess serine inhibited the uptake of PFS micelles, which demonstrated that serine receptors played a positive role in the internalization of PFS. The more interesting thing was that the uptake inhibition impacted on normal cells but not on tumor cells at the physiological concentration of serine. The difference in the uptake of PFS micelles was fourfold as high between the tumor cells and the normal cells, which indicated that PFS micelles had good tumor targeting in vitro. In conclusion, PFS

  15. Graphene-coated polymeric anion exchangers for ion chromatography

    International Nuclear Information System (INIS)

    Zhang, Kai; Cao, Minyi; Lou, Chaoyan; Wu, Shuchao; Zhang, Peimin; Zhi, Mingyu; Zhu, Yan

    2017-01-01

    Carbonaceous stationary phases have gained much attention for their peculiar selectivity and robustness. Herein we report the fabrication and application of a graphene-coated polymeric stationary phase for anion exchange chromatography. The graphene-coated particles were fabricated by a facile evaporation-reduction method. These hydrophilic particles were proven appropriate substrates for grafting of hyperbranched condensation polymers (HBCPs) to make pellicular anion exchangers. The new phase was characterized by zeta potentials, Fourier transform infrared spectroscopy, thermogravimetry and scanning electron microscope. Frontal displacement chromatography showed that the capacities of the anion exchangers were tuned by both graphene amount and HBCPs layer count. The chromatographic performance of graphene-coated anion exchangers was demonstrated with separation of inorganic anions, organic acids, carbohydrates and amino acids. Good reproducibility was obtained by consecutive injections, indicating high chemical stability of the coating. - Highlights: • Graphene-coated polymeric particles were fabricated by a facile method. • Hyperbranched condensation polymers (HBCPs) were grafted from graphene-coated particles to make anion exchangers. • Graphene amount and HBCPs layer count had significant effects on the anion exchange capacities. • Separation of diverse anionic analytes on the anion exchangers was demonstrated. • The prepared anion exchangers exhibited high stability.

  16. Graphene-coated polymeric anion exchangers for ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Cao, Minyi; Lou, Chaoyan [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Wu, Shuchao, E-mail: wushch2002@163.com [Zhejiang Institute of Geology and Mineral Resources, Hangzhou 310007 (China); Zhang, Peimin [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Zhi, Mingyu [Hangzhou Vocational & Technical College, Hangzhou, 310018 (China); Zhu, Yan, E-mail: zhuyan@zju.edu.cn [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China)

    2017-06-01

    Carbonaceous stationary phases have gained much attention for their peculiar selectivity and robustness. Herein we report the fabrication and application of a graphene-coated polymeric stationary phase for anion exchange chromatography. The graphene-coated particles were fabricated by a facile evaporation-reduction method. These hydrophilic particles were proven appropriate substrates for grafting of hyperbranched condensation polymers (HBCPs) to make pellicular anion exchangers. The new phase was characterized by zeta potentials, Fourier transform infrared spectroscopy, thermogravimetry and scanning electron microscope. Frontal displacement chromatography showed that the capacities of the anion exchangers were tuned by both graphene amount and HBCPs layer count. The chromatographic performance of graphene-coated anion exchangers was demonstrated with separation of inorganic anions, organic acids, carbohydrates and amino acids. Good reproducibility was obtained by consecutive injections, indicating high chemical stability of the coating. - Highlights: • Graphene-coated polymeric particles were fabricated by a facile method. • Hyperbranched condensation polymers (HBCPs) were grafted from graphene-coated particles to make anion exchangers. • Graphene amount and HBCPs layer count had significant effects on the anion exchange capacities. • Separation of diverse anionic analytes on the anion exchangers was demonstrated. • The prepared anion exchangers exhibited high stability.

  17. Side-chain-controlled self-assembly of polystyrene-polypeptide miktoarm star copolymers

    KAUST Repository

    Junnila, Susanna

    2012-03-27

    We show how the self-assembly of miktoarm star copolymers can be controlled by modifying the side chains of their polypeptide arms, using A 2B and A 2B 2 type polymer/polypeptide hybrids (macromolecular chimeras). Initially synthesized PS 2PBLL and PS 2PBLL 2 (PS, polystyrene; PBLL, poly(ε-tert-butyloxycarbonyl-l-lysine) ) miktoarms were first deprotected to PS 2PLLHCl and PS 2PLLHCl 2 miktoarms (PLLHCl, poly(l-lysine hydrochloride)) and then complexed ionically with sodium dodecyl sulfonate (DS) to give the supramolecular complexes PS 2PLL(DS) and PS 2(PLL(DS)) 2. The solid-state self-assemblies of these six miktoarm systems were studied by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and small- and wide-angle X-ray scattering (SAXS, WAXS). The side chains of the polypeptide arms were observed to have a large effect on the solubility, polypeptide conformation, and self-assembly of the miktoarms. Three main categories were observed: (i) lamellar self-assemblies at the block copolymer length scale with packed layers of α-helices in PS 2PBLL and PS 2PBLL 2; (ii) charge-clustered polypeptide micelles with less-defined conformations in a nonordered lattice within a PS matrix in PS 2PLLHCl and PS 2PLLHCl 2; (iii) lamellar polypeptide-surfactant self-assemblies with β-sheet conformation in PS 2PLL(DS) and PS 2(PLL(DS)) 2 which dominate over the formation of block copolymer scale structures. Differences between the 3- and 4-arm systems illustrate how packing frustration between the coil-like PS arms and rigid polypeptide conformations can be relieved by the right number of arms, leading to differences in the extent of order. © 2012 American Chemical Society.

  18. The mining of toxin-like polypeptides from EST database by single residue distribution analysis

    Science.gov (United States)

    2011-01-01

    Background Novel high throughput sequencing technologies require permanent development of bioinformatics data processing methods. Among them, rapid and reliable identification of encoded proteins plays a pivotal role. To search for particular protein families, the amino acid sequence motifs suitable for selective screening of nucleotide sequence databases may be used. In this work, we suggest a novel method for simplified representation of protein amino acid sequences named Single Residue Distribution Analysis, which is applicable both for homology search and database screening. Results Using the procedure developed, a search for amino acid sequence motifs in sea anemone polypeptides was performed, and 14 different motifs with broad and low specificity were discriminated. The adequacy of motifs for mining toxin-like sequences was confirmed by their ability to identify 100% toxin-like anemone polypeptides in the reference polypeptide database. The employment of novel motifs for the search of polypeptide toxins in Anemonia viridis EST dataset allowed us to identify 89 putative toxin precursors. The translated and modified ESTs were scanned using a special algorithm. In addition to direct comparison with the motifs developed, the putative signal peptides were predicted and homology with known structures was examined. Conclusions The suggested method may be used to retrieve structures of interest from the EST databases using simple amino acid sequence motifs as templates. The efficiency of the procedure for directed search of polypeptides is higher than that of most currently used methods. Analysis of 39939 ESTs of sea anemone Anemonia viridis resulted in identification of five protein precursors of earlier described toxins, discovery of 43 novel polypeptide toxins, and prediction of 39 putative polypeptide toxin sequences. In addition, two precursors of novel peptides presumably displaying neuronal function were disclosed. PMID:21281459

  19. The effect of gastric inhibitory polypeptide on intestinal glucose absorption and intestinal motility in mice

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Eiichi [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Hosokawa, Masaya [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Faculty of Human Sciences, Tezukayama Gakuin University, Osaka (Japan); Harada, Norio; Yamane, Shunsuke; Hamasaki, Akihiro; Toyoda, Kentaro; Fujimoto, Shimpei; Fujita, Yoshihito; Fukuda, Kazuhito [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Tsukiyama, Katsushi; Yamada, Yuichiro [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Department of Internal Medicine, Division of Endocrinology, Diabetes and Geriatric Medicine, Akita University School of Medicine, Akita (Japan); Seino, Yutaka [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); Kansai Electric Power Hospital, Osaka (Japan); Inagaki, Nobuya, E-mail: inagaki@metab.kuhp.kyoto-u.ac.jp [Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University (Japan); CREST of Japan Science and Technology Cooperation (JST), Kyoto (Japan)

    2011-01-07

    Research highlights: {yields} Exogenous GIP inhibits intestinal motility through a somatostatin-mediated pathway. {yields} Exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility. {yields} The GIP-receptor-mediated action in intestine does not involve in GLP-1-mediated pathway. -- Abstract: Gastric inhibitory polypeptide (GIP) is released from the small intestine upon meal ingestion and increases insulin secretion from pancreatic {beta} cells. Although the GIP receptor is known to be expressed in small intestine, the effects of GIP in small intestine are not fully understood. This study was designed to clarify the effect of GIP on intestinal glucose absorption and intestinal motility. Intestinal glucose absorption in vivo was measured by single-pass perfusion method. Incorporation of [{sup 14}C]-glucose into everted jejunal rings in vitro was used to evaluate the effect of GIP on sodium-glucose co-transporter (SGLT). Motility of small intestine was measured by intestinal transit after oral administration of a non-absorbed marker. Intraperitoneal administration of GIP inhibited glucose absorption in wild-type mice in a concentration-dependent manner, showing maximum decrease at the dosage of 50 nmol/kg body weight. In glucagon-like-peptide-1 (GLP-1) receptor-deficient mice, GIP inhibited glucose absorption as in wild-type mice. In vitro examination of [{sup 14}C]-glucose uptake revealed that 100 nM GIP did not change SGLT-dependent glucose uptake in wild-type mice. After intraperitoneal administration of GIP (50 nmol/kg body weight), small intestinal transit was inhibited to 40% in both wild-type and GLP-1 receptor-deficient mice. Furthermore, a somatostatin receptor antagonist, cyclosomatostatin, reduced the inhibitory effect of GIP on both intestinal transit and glucose absorption in wild-type mice. These results demonstrate that exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility through a somatostatin

  20. The effect of gastric inhibitory polypeptide on intestinal glucose absorption and intestinal motility in mice

    International Nuclear Information System (INIS)

    Ogawa, Eiichi; Hosokawa, Masaya; Harada, Norio; Yamane, Shunsuke; Hamasaki, Akihiro; Toyoda, Kentaro; Fujimoto, Shimpei; Fujita, Yoshihito; Fukuda, Kazuhito; Tsukiyama, Katsushi; Yamada, Yuichiro; Seino, Yutaka; Inagaki, Nobuya

    2011-01-01

    Research highlights: → Exogenous GIP inhibits intestinal motility through a somatostatin-mediated pathway. → Exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility. → The GIP-receptor-mediated action in intestine does not involve in GLP-1-mediated pathway. -- Abstract: Gastric inhibitory polypeptide (GIP) is released from the small intestine upon meal ingestion and increases insulin secretion from pancreatic β cells. Although the GIP receptor is known to be expressed in small intestine, the effects of GIP in small intestine are not fully understood. This study was designed to clarify the effect of GIP on intestinal glucose absorption and intestinal motility. Intestinal glucose absorption in vivo was measured by single-pass perfusion method. Incorporation of [ 14 C]-glucose into everted jejunal rings in vitro was used to evaluate the effect of GIP on sodium-glucose co-transporter (SGLT). Motility of small intestine was measured by intestinal transit after oral administration of a non-absorbed marker. Intraperitoneal administration of GIP inhibited glucose absorption in wild-type mice in a concentration-dependent manner, showing maximum decrease at the dosage of 50 nmol/kg body weight. In glucagon-like-peptide-1 (GLP-1) receptor-deficient mice, GIP inhibited glucose absorption as in wild-type mice. In vitro examination of [ 14 C]-glucose uptake revealed that 100 nM GIP did not change SGLT-dependent glucose uptake in wild-type mice. After intraperitoneal administration of GIP (50 nmol/kg body weight), small intestinal transit was inhibited to 40% in both wild-type and GLP-1 receptor-deficient mice. Furthermore, a somatostatin receptor antagonist, cyclosomatostatin, reduced the inhibitory effect of GIP on both intestinal transit and glucose absorption in wild-type mice. These results demonstrate that exogenous GIP inhibits intestinal glucose absorption by reducing intestinal motility through a somatostatin-mediated pathway rather

  1. Recent advances in amino acid N-carboxyanhydrides and synthetic polypeptides: chemistry, self-assembly and biological applications.

    Science.gov (United States)

    Lu, Hua; Wang, Jing; Song, Ziyuan; Yin, Lichen; Zhang, Yanfeng; Tang, Haoyu; Tu, Chunlai; Lin, Yao; Cheng, Jianjun

    2014-01-07

    Polypeptides are fascinating materials with unique properties for various biological materials. We highlight here recent advances in amino acid N-carboxyanhydrides (NCAs) and synthetic polypeptides from the aspects of chemistry, self-assembly and biological applications. New synthetic methodologies, mechanistic studies and optimization of polymerization conditions for the preparation of well-defined novel polypeptides are comprehensively reviewed and evaluated. Functional polypeptides, mostly prepared from novel NCA monomers, with ultra-stable helical conformation, stimuli-sensitive properties, or glycoprotein mimetics are summarized. We also highlight a number of interesting self-assembled structures of polypeptides in solid state and solution, with particular emphasis on those structures other than amphiphilic self-assembly. The biological applications of polypeptides in drug and gene delivery are also reviewed. Future directions and perspectives are discussed in the conclusion.

  2. Interaction Potential of the Multitargeted Receptor Tyrosine Kinase Inhibitor Dovitinib with Drug Transporters and Drug Metabolising Enzymes Assessed in Vitro

    Directory of Open Access Journals (Sweden)

    Johanna Weiss

    2014-12-01

    Full Text Available Dovitinib (TKI-258 is under development for the treatment of diverse cancer entities. No published information on its pharmacokinetic drug interaction potential is available. Thus, we assessed its interaction with important drug metabolising enzymes and drug transporters and its efficacy in multidrug resistant cells in vitro. P-glycoprotein (P-gp, MDR1, ABCB1 inhibition was evaluated by calcein assay, inhibition of breast cancer resistance protein (BCRP, ABCG2 by pheophorbide A efflux, and inhibition of organic anion transporting polypeptides (OATPs by 8-fluorescein-cAMP uptake. Inhibition of cytochrome P450 3A4, 2C19, and 2D6 was assessed by using commercial kits. Induction of transporters and enzymes was quantified by real-time RT-PCR. Possible aryl hydrocarbon receptor (AhR activating properties were assessed by a reporter gene assay. Substrate characteristics were evaluated by growth inhibition assays in cells over-expressing P-gp or BCRP. Dovitinib weakly inhibited CYP2C19, CYP3A4, P-gp and OATPs. The strongest inhibition was observed for BCRP (IC50 = 10.3 ± 4.5 μM. Among the genes investigated, dovitinib only induced mRNA expression of CYP1A1, CYP1A2, ABCC3 (coding for multidrug resistance-associated protein 3, and ABCG2 and suppressed mRNA expression of some transporters and drug metabolising enzymes. AhR reporter gene assay demonstrated that dovitinib is an activator of this nuclear receptor. Dovitinib retained its efficacy in cell lines over-expressing P-gp or BCRP. Our analysis indicates that dovitinib will most likely retain its efficacy in tumours over-expressing P-gp or BCRP and gives first evidence that dovitinib might act as a perpetrator drug in pharmacokinetic drug–drug interactions.

  3. Probes for anionic cell surface detection

    Science.gov (United States)

    Smith, Bradley D.

    2013-03-05

    Embodiments of the present invention are generally directed to compositions comprising a class of molecular probes for detecting the presence of anionic cell surfaces. Embodiments include compositions that are enriched for these compositions and preparations, particularly preparations suitable for use as laboratory/clinical reagents and diagnostic indicators, either alone or as part of a kit. An embodiment of the invention provides for a highly selective agent useful in the discernment and identification of dead or dying cells, such as apoptotic cells, in a relatively calcium-free environment. An embodiment of the invention provides a selective agent for the identification of bacteria in a mixed population of bacterial cells and nonbacterial cells.

  4. Recognition and sensing of fluoride anion.

    Science.gov (United States)

    Cametti, Massimo; Rissanen, Kari

    2009-05-28

    Fluoride anion recognition is attracting a mounting interest in the scientific community due to its duplicitous nature. It is a useful chemical for many industrial applications, and it has been used in human diet, but, recently it has been accused for several human pathologies. Here we describe the ample panorama of different approaches the chemists world-wide have employed to face the challenge of fluoride binding, and we outline some of the research which in our view can contribute to the development of this field, especially when fluoride binding has to be achieved in highly competitive protic solvents and water.

  5. Volume-sensitive anion channels mediate osmosensitive glutathione release from rat thymocytes.

    Directory of Open Access Journals (Sweden)

    Ravshan Z Sabirov

    Full Text Available Glutathione (GSH is a negatively charged tripeptide, which is a major determinant of the cellular redox state and defense against oxidative stress. It is assembled inside and degraded outside the cells and is released under various physiological and pathophysiological conditions. The GSH release mechanism is poorly understood at present. In our experiments, freshly isolated rat thymocytes were found to release GSH under normal isotonic conditions at a low rate of 0.82±0.07 attomol/cell/min and that was greatly enhanced under hypoosomotic stimulation to reach a level of 6.1±0.4 attomol/cell/min. The swelling-induced GSH release was proportional to the cell density in the suspension and was temperature-dependent with relatively low activation energy of 5.4±0.6 kcal/mol indicating a predominant diffusion mechanism of GSH translocation. The osmosensitive release of GSH was significantly inhibited by blockers of volume-sensitive outwardly rectifying (VSOR anion channel, DCPIB and phloretin. In patch-clamp experiments, osmotic swelling activated large anionic conductance with the VSOR channel phenotype. Anion replacement studies suggested that the thymic VSOR anion channel is permeable to GSH(- with the permeability ratio P(GSH/P(Cl of 0.32 for influx and 0.10 for efflux of GSH. The osmosensitive GSH release was trans-stimulated by SLCO/OATP substrates, probenecid, taurocholic acid and estrone sulfate, and inhibited by an SLC22A/OAT blocker, p-aminohippuric acid (PAH. The inhibition by PAH was additive to the effect of DCPIB or phloretin implying that PAH and DCPIB/phloretin affected separate pathways. We suggest that the VSOR anion channel constitutes a major part of the γ-glutamyl cycle in thymocytes and, in cooperation with OATP-like and OAT-like transporters, provides a pathway for the GSH efflux from osmotically swollen cells.

  6. Polycondensation of Asparagine-comprising Dipeptides in Aqueous Media-A Simulation of Polypeptide Formation in Primordial Earth Hydrosphere

    Science.gov (United States)

    Munegumi, Toratane; Tanikawa, Naoya

    2017-09-01

    Asparagine and aspartic acid might have mutually transformed in the primordial hydrosphere of the earth, if ammonia and aspartic acid had existed in equilibrium. These amino acids seem to contribute to polypeptides, while the simple amino acids glycine and alanine easily form cyclic dipeptides and do not achieve long peptide chains. Asparagine-comprising dipeptides contribute some kinds of activation forms of dipeptides because these can polymerize faster than asparagine only. The new finding of polypeptide formation suggests a pathway of sequential polypeptides to evolve a diversity of polypeptides.

  7. Brachytherapy Using Elastin-Like Polypeptides with (131)I Inhibit Tumor Growth in Rabbits with VX2 Liver Tumor.

    Science.gov (United States)

    Liu, Xinpei; Shen, Yiming; Zhang, Xuqian; Lin, Rui; Jia, Qiang; Chang, Yixiang; Liu, Wenge; Liu, Wentian

    2016-10-01

    Brachytherapy is a targeted type of radiotherapy utilized in the treatment of cancers. Elastin-like polypeptides are a unique class of genetically engineered peptide polymers that have several attractive properties for brachytherapy. To explore the feasibility and application of brachytherapy for VX2 liver tumor using elastin-like polypeptides with (131)I so as to provide reliable experimental evidence for a new promising treatment of liver cancer. Elastin-like polypeptide as carrier was labeled with (131)I using the iodogen method. Ten eligible rabbits with VX2 liver tumor were randomly divided into the treatment group (n = 5) and control group (n = 5). The treatment group received brachytherapy using elastin-like polypeptide with (131)I, and in the control group, elastin-like polypeptide was injected into the VX2 liver tumor as a control. Periodic biochemical and imaging surveillances were required to assess treatment efficacy. The stability of elastin-like polypeptide with (131)I in vitro was maintained at over 96.8 % for 96 h. Biochemistry and imaging indicated brachytherapy using elastin-like polypeptide with (131)I for liver tumor can improve liver function and inhibit tumor growth (P polypeptide can be an ideal carrier of (131)I and have high labeling efficiency, radiochemical purity and stability. Brachytherapy using elastin-like polypeptide with (131)I for liver tumor is a useful therapy that possesses high antitumor efficacy advantages.

  8. Mechanism of ochratoxin A transport in kidney

    Energy Technology Data Exchange (ETDEWEB)

    Sokol, P.P.; Ripich, G.; Holohan, P.D.; Ross, C.R.

    1988-08-01

    The effect of the fungal metabolite (mycotoxin) Ochratoxin A (OTA) on the transport of p-amino(/sup 3/H)hippurate (PAH), a prototypic organic anion, was examined in renal brush border (BBMV) and basolateral membrane vesicles (BLMV). OTA was as effective an inhibitor of PAH uptake in both membranes as probenecid. The dose response curves for OTA in BBMV and BLMV gave IC50 values of 20 +/- 6 and 32 +/- 7 microM, respectively. The effect was specific since the transport of the organic cation N1-methylnicotinamide was not affected. The phenomenon of counterflow was studied to establish that OTA is translocated. OTA produced trans stimulation of PAH transport in both BBMV and BLMV, demonstrating that OTA is transported across both these membranes. The data suggest that OTA interacts with the PAH transport system in both BBMV and BLMV. We conclude that OTA transport in the kidney is mediated via the renal organic anion transport system.

  9. Fabrication of genetically engineered polypeptide@quantum dots hybrid nanogels for targeted imaging

    Science.gov (United States)

    Yang, Jie; Yao, Ming-Hao; Zhao, Dong-Hui; Zhang, Xiao-Shuai; Jin, Rui-Mei; Zhao, Yuan-Di; Liu, Bo

    2017-08-01

    Nanogels have been widely used as multifunctional drug delivery carriers because of high water content, biocompatibility, and high loading capability. We designed and biosynthesized two triblock artificial polypeptides PC10A and PC10ARGD as vehicles for encapsulating hydrophobic materials. These polypeptides can form nanogels by self-assembly when the concentration is below 2% ( w/ v). The physical properties of nanogels, including size, surface potential, and targeting domain, are able to be tuned. Hydrophobic materials from molecular size to nano-size can be loaded into the polypeptide nanogels to form hybrid nanogels. Hydrophobic quantum dots CdSe@ZnS below 10 nM were loaded into the polypeptide nanogels by ultrasonic treatment. Encapsulation endows hydrophobic QDs with good tunability of size, water solubility, stability, targeting, and biocompatibility. PC10ARGD nanogels and PC10ARGD@QDs hybrid nanogels showed excellent biocompatibility, which the cellular viabilities of HeLa and MCF-7 cells treated with 1% PC10ARGD nanogels and PC10ARGD@QDs hybrid nanogels contained 20 nM QDs were above 90 and 80%, respectively. PC10ARGD@QDs hybrid nanogels with an arginine-glycine-aspartic acid motif present efficient receptor-mediated endocytosis in α v β 3 overexpressing HeLa cells but not in the control MCF-7 cells as analyzed by confocal microscopy. These results demonstrate that such polypeptide nanogels as nanocarriers are expected to have great potential applications in biomedicine.

  10. Congenital deficiency of two polypeptide subunits of the iron-protein fragment of mitochondrial complex I.

    Science.gov (United States)

    Moreadith, R W; Cleeter, M W; Ragan, C I; Batshaw, M L; Lehninger, A L

    1987-02-01

    Recently, we described a patient with severe lactic acidosis due to congenital complex I (NADH-ubiquinone oxidoreductase) deficiency. We now report further enzymatic and immunological characterizations. Both NADH and ferricyanide titrations of complex I activity (measured as NADH-ferricyanide reductase) were distinctly altered in the mitochondria from the patient's tissues. In addition, antisera against complex I immunoprecipitated NADH-ferricyanide reductase from the control but not the patient's mitochondria. However, immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of complex I polypeptides demonstrated that the majority of the 25 polypeptides comprising complex I were present in the affected mitochondria. A more detailed analysis using subunit selective antisera against the main polypeptides of the iron-protein fragments of complex I revealed a selective absence of the 75- and 13-kD polypeptides. These findings suggest that the underlying basis for this patient's disease was a congenital deficiency of at least two polypeptides comprising the iron-protein fragment of complex I, which resulted in the inability to correctly assemble a functional enzyme complex.

  11. Competition between surface adsorption and folding of fibril-forming polypeptides.

    Science.gov (United States)

    Ni, Ran; Kleijn, J Mieke; Abeln, Sanne; Cohen Stuart, Martien A; Bolhuis, Peter G

    2015-02-01

    Self-assembly of polypeptides into fibrillar structures can be initiated by planar surfaces that interact favorably with certain residues. Using a coarse-grained model, we systematically studied the folding and adsorption behavior of a β-roll forming polypeptide. We find that there are two different folding pathways depending on the temperature: (i) at low temperature, the polypeptide folds in solution into a β-roll before adsorbing onto the attractive surface; (ii) at higher temperature, the polypeptide first adsorbs in a disordered state and folds while on the surface. The folding temperature increases with increasing attraction as the folded β-roll is stabilized by the surface. Surprisingly, further increasing the attraction lowers the folding temperature again, as strong attraction also stabilizes the adsorbed disordered state, which competes with folding of the polypeptide. Our results suggest that to enhance the folding, one should use a weakly attractive surface. They also explain the recent experimental observation of the nonmonotonic effect of charge on the fibril formation on an oppositely charged surface [C. Charbonneau et al., ACS Nano 8, 2328 (2014)].

  12. Ultrastructural and biochemical detection of biotin and biotinylated polypeptides in Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Santos P.R.P.

    1997-01-01

    Full Text Available Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of nonspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the conjugate was blocked with biotinamidecaproate-N-hydroxysuccinimide ester (BcapNHS before biotin-streptavidin blotting. No bands were detected on the nitrocellulose sheet, demonstrating the specific recognition of biotin by the streptavidin present in the conjugate. Whole cercariae and cercarial bodies and tails showed several endogenous biotinylated polypeptides. The biotin concentration was 13 µg/190,000 cercariae. Adult worms presented less endogenous biotinylated polypeptides than cercariae. These results may be due to changes in the environment from aerobic to anaerobic conditions when cercarial bodies (schistosomula are transformed into adult worms and a decrease in CO2 production may occur. Cercariae, cercarial bodies and adult male worms were examined by transmission electron microscopy employing an avidin-colloidal gold conjugate for the detection of endogenous biotin. Gold particles were distributed mainly on the muscle fibers, but dispersed granules were observed in the tegument, mitochondria and cytosol. The discovery of endogenous biotin in S. mansoni should be investigated in order to clarify the function of this vitamin in the parasite

  13. Competition between surface adsorption and folding of fibril-forming polypeptides

    Science.gov (United States)

    Ni, Ran; Kleijn, J. Mieke; Abeln, Sanne; Cohen Stuart, Martien A.; Bolhuis, Peter G.

    2015-02-01

    Self-assembly of polypeptides into fibrillar structures can be initiated by planar surfaces that interact favorably with certain residues. Using a coarse-grained model, we systematically studied the folding and adsorption behavior of a β -roll forming polypeptide. We find that there are two different folding pathways depending on the temperature: (i) at low temperature, the polypeptide folds in solution into a β -roll before adsorbing onto the attractive surface; (ii) at higher temperature, the polypeptide first adsorbs in a disordered state and folds while on the surface. The folding temperature increases with increasing attraction as the folded β -roll is stabilized by the surface. Surprisingly, further increasing the attraction lowers the folding temperature again, as strong attraction also stabilizes the adsorbed disordered state, which competes with folding of the polypeptide. Our results suggest that to enhance the folding, one should use a weakly attractive surface. They also explain the recent experimental observation of the nonmonotonic effect of charge on the fibril formation on an oppositely charged surface [C. Charbonneau et al., ACS Nano 8, 2328 (2014), 10.1021/nn405799t].

  14. Fluorescence probe of polypeptide conformational dynamics in gas phase and in solution

    Science.gov (United States)

    Iavarone, Anthony T.; Meinen, Jan; Schulze, Susanne; Parks, Joel H.

    2006-07-01

    Fluorescence measurements of polypeptides derivatized with the fluorescent dye BODIPY TMR have been used to probe the polypeptide conformational dynamics as a function of temperature and charge state. Measurements of (BODIPY TMR)-[Pro]n-Arg-Trp and (BODIPY TMR)-[Gly-Ser]m-Arg-Trp have been performed for charge states 1+ and 2+ of n = 4 and 10 and m = 2 and 5. The 2+ charge states of both of these polypeptides exhibit similar temperature dependences for equal chain lengths (n = 4, m = 2 and n = 10, m = 5) and suggest conformations dominated by Coulomb repulsion. In the absence of such Coulomb repulsion, the 1+ charge state conformations appear to be characterized by the flexibility of the polypeptide chain for which [Gly-Ser]m > [Pro]n. Comparisons of these gas phase polypeptide measurements with corresponding measurements in solution provide a direct measure of the effects of solvent on the conformational dynamics. The change in fluorescence as a function of temperature in the gas phase is two orders of magnitude greater than that in solution, a dramatic result we attribute to the restrictions on intramolecular dynamics imposed by diffusion-limited kinetics and the lack of shielding by solvent. Measurements were also made of unsolvated Pron peptides without the tryptophan (Trp) residue to isolate the interaction of the fluorescent dye with charges.

  15. Photoelectron Spectroscopy and Theoretical Studies of Anion-pi Interactions: Binding Strength and Anion Specificity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian; Zhou, Bin; Sun, Zhenrong; Wang, Xue B.

    2015-01-01

    Proposed in theory and confirmed to exist, anion–π interactions have been recognized as new and important non-covalent binding forces. Despite extensive theoretical studies, numerous crystal structural identifications, and a plethora of solution phase investigations, intrinsic anion–π interaction strengths that are free from complications of condensed phases’ environments, have not been directly measured in the gas phase. Herein we present a joint photoelectron spectroscopic and theoretical study on this subject, in which tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic was used as a charge-neutral molecular host to probe its interactions with a series of anions with distinctly different shapes and charge states (spherical halides Cl⁻, Br⁻, I⁻, linear thiocyanate SCN⁻, trigonal planar nitrate NO₃⁻, pyramidic iodate IO₃⁻, and tetrahedral sulfate SO₄²⁻). The binding energies of the resultant gaseous 1:1 complexes (1•Cl⁻,1•Br⁻, 1•I⁻, 1•SCN⁻, 1•NO₃⁻, 1•IO₃⁻ and 1•SO₄²⁻) were directly measured experimentally, exhibiting substantial non-covalent interactions with pronounced anion specific effects. The binding strengths of Cl⁻, NO₃⁻, IO₃⁻ with 1 are found to be strongest among all singly charged anions, amounting to ca. 30 kcal/mol, but only about 40% of that between 1 and SO₄²⁻. Quantum chemical calculations reveal that all anions reside in the center of the cavity of 1 with anion–π binding motif in the complexes’ optimized structures, where 1 is seen to be able to self-regulate its cavity structure to accommodate anions of different geometries and three-dimensional shapes. Electron density surface and natural bond orbital charge distribution analysis further support anion–π binding formation. The calculated binding energies of the anions and 1 nicely reproduce the experimentally estimated electron binding energy increase. This work

  16. The quantum structure of anionic hydrogen clusters

    Science.gov (United States)

    Calvo, F.; Yurtsever, E.

    2018-03-01

    A flexible and polarizable interatomic potential has been developed to model hydrogen clusters interacting with one hydrogen anion, (H2)nH-, in a broad range of sizes n = 1-54 and parametrized against coupled cluster quantum chemical calculations. Using path-integral molecular dynamics simulations at 1 K initiated from the putative classical global minima, the equilibrium structures are found to generally rely on icosahedral shells with the hydrogen molecules pointing toward the anion, producing geometric magic numbers at sizes n = 12, 32, and 44 that are in agreement with recent mass spectrometry measurements. The energetic stability of the clusters is also connected with the extent of vibrational delocalization, measured here by the fluctuations among inherent structures hidden in the vibrational wave function. As the clusters grow, the outer molecules become increasingly free to rotate, and strong finite size effects are also found between magic numbers, associated with more prominent vibrational delocalization. The effective icosahedral structure of the 44-molecule cluster is found to originate from quantum nuclear effects as well, the classical structure showing no particular symmetry.

  17. An intracellular anion channel critical for pigmentation

    Science.gov (United States)

    Bellono, Nicholas W; Escobar, Iliana E; Lefkovith, Ariel J; Marks, Michael S; Oancea, Elena

    2014-01-01

    Intracellular ion channels are essential regulators of organellar and cellular function, yet the molecular identity and physiological role of many of these channels remains elusive. In particular, no ion channel has been characterized in melanosomes, organelles that produce and store the major mammalian pigment melanin. Defects in melanosome function cause albinism, characterized by vision and pigmentation deficits, impaired retinal development, and increased susceptibility to skin and eye cancers. The most common form of albinism is caused by mutations in oculocutaneous albinism II (OCA2), a melanosome-specific transmembrane protein with unknown function. Here we used direct patch-clamp of skin and eye melanosomes to identify a novel chloride-selective anion conductance mediated by OCA2 and required for melanin production. Expression of OCA2 increases organelle pH, suggesting that the chloride channel might regulate melanin synthesis by modulating melanosome pH. Thus, a melanosomal anion channel that requires OCA2 is essential for skin and eye pigmentation. DOI: http://dx.doi.org/10.7554/eLife.04543.001 PMID:25513726

  18. Isobar Separator for Anions: Current status

    International Nuclear Information System (INIS)

    Alary, Jean-François; Javahery, Gholamreza; Kieser, William; Zhao, Xiao-Lei; Litherland, Albert; Cousins, Lisa; Charles, Christopher

    2015-01-01

    The Isobar Separator for Anions (ISA) is an emerging separation technique of isobars applied first to the selective removal of 36 S from 36 Cl, achieving a relative suppression ratio of 6 orders of magnitude. Using a radio-frequency quadrupole (RFQ) column incorporating low energy gas cells, this innovative technique enables the use of a wide range of low energy ion–molecule reactions and collisional-induced dissociation processes for suppressing specific atomic of molecular anions with a high degree of selectivity. Other elemental pairs (analyte/isobar) successfully separated at AMS level include Ca/K, Sr/(Y, Zr), Cs/Ba, Hf/W and Pu/U. In view of these initial successes, an effort to develop a version of the ISA that can be used as a robust technique for routine AMS analysis has been undertaken. We will discuss the detailed layout of a practical ISA and the functional requirements that a combined ISA/AMS should meet. These concepts are currently being integrated in a pre-commercial ISA system that will be installed soon at the newly established A.E. Lalonde Laboratory in Ottawa, Canada.

  19. Isobar Separator for Anions: Current status

    Energy Technology Data Exchange (ETDEWEB)

    Alary, Jean-François, E-mail: alaryjf@isobarex.ca [Isobarex Corp., 32 Nixon Road Unit #1, Bolton, ON L7E 1W2 (Canada); Javahery, Gholamreza [IONICS Mass Spectrometry, 32 Nixon Road Unit #1, Bolton, ON L7E 1W2 (Canada); Kieser, William; Zhao, Xiao-Lei [Andre E. Lalonde Accelerator Mass Spectrometry Laboratory, Advanced Research Complex, University of Ottawa, 25 Templeton Street, Ottawa, ON K1N 6N5 (Canada); Litherland, Albert [IsoTrace Laboratory, Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3B1 (Canada); Cousins, Lisa [IONICS Mass Spectrometry, 32 Nixon Road Unit #1, Bolton, ON L7E 1W2 (Canada); Charles, Christopher [Andre E. Lalonde Accelerator Mass Spectrometry Laboratory, Advanced Research Complex, University of Ottawa, 25 Templeton Street, Ottawa, ON K1N 6N5 (Canada)

    2015-10-15

    The Isobar Separator for Anions (ISA) is an emerging separation technique of isobars applied first to the selective removal of {sup 36}S from {sup 36}Cl, achieving a relative suppression ratio of 6 orders of magnitude. Using a radio-frequency quadrupole (RFQ) column incorporating low energy gas cells, this innovative technique enables the use of a wide range of low energy ion–molecule reactions and collisional-induced dissociation processes for suppressing specific atomic of molecular anions with a high degree of selectivity. Other elemental pairs (analyte/isobar) successfully separated at AMS level include Ca/K, Sr/(Y, Zr), Cs/Ba, Hf/W and Pu/U. In view of these initial successes, an effort to develop a version of the ISA that can be used as a robust technique for routine AMS analysis has been undertaken. We will discuss the detailed layout of a practical ISA and the functional requirements that a combined ISA/AMS should meet. These concepts are currently being integrated in a pre-commercial ISA system that will be installed soon at the newly established A.E. Lalonde Laboratory in Ottawa, Canada.

  20. Anion photoelectron spectroscopy of radicals and clusters

    Energy Technology Data Exchange (ETDEWEB)

    Travis, Taylor R. [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying 2Σ and 2π states of C2nH (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C2H and C4H. Other radicals studied include NCN and I3. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I3 revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

  1. Ion-selective electrode and anion gap range: What should the anion gap be?

    Directory of Open Access Journals (Sweden)

    Sadjadi SA

    2013-06-01

    Full Text Available Seyed-Ali Sadjadi, Rendell Manalo, Navin Jaipaul, James McMillan Jerry L Pettis Memorial Veterans Medical Center, Loma Linda University School of Medicine, Loma Linda, CA, USA Background: Using flame photometry technique in the 1970s, the normal value of anion gap (AG was determined to be 12 ± 4 meq/L. However, with introduction of the autoanalyzers using an ion-selective electrode (ISE, the anion gap value has fallen to lower levels. Methods: A retrospective study of US veterans from a single medical center was performed to determine the value of the anion gap in subjects with normal renal function and normal serum albumin and in patients with lactic acidosis and end-stage renal disease on dialysis. Results: In 409 patients with an estimated glomerular filtration rate ≥60 mL/min/1.73 m2 body surface area and serum albumin ≥4 g/dL, the mean AG was 7.2 ± 2 (range 3–11 meq/L. In 299 patients with lactic acidosis (lactate level ≥4 meq/L and 68 patients with end-stage renal disease on dialysis, the mean AG was 12.5 meq/L and 12.4 meq/L, respectively. A value <2 meq/L should be considered a low anion gap and a possible clue to drug intoxication and paraproteinemic disorders. Conclusion: With the advent of ISE for measurement of analytes, the value of the anion gap has fallen. Physicians need to be aware of the normal AG value in their respective institutions, and laboratories need to have an established value for AG based on the type of instrument they are using. Keywords: acidosis, electrolytes, ESRD

  2. The TOM complex is involved in the release of superoxide anion from mitochondria.

    Science.gov (United States)

    Budzińska, Małgorzata; Gałgańska, Hanna; Karachitos, Andonis; Wojtkowska, Małgorzata; Kmita, Hanna

    2009-08-01

    Available data indicate that superoxide anion (O(2)(*-) ) is released from mitochondria, but apart from VDAC (voltage dependent anion channel), the proteins involved in its transport across the mitochondrial outer membrane still remain elusive. Using mitochondria of the yeast Saccharomyces cerevisiae mutant depleted of VDAC (Deltapor1 mutant) and the isogenic wild type, we studied the role of the TOM complex (translocase of the outer membrane) in the efflux of O(2)(*-) from the mitochondria. We found that blocking the TOM complex with the fusion protein pb(2)-DHFR decreased O(2)(*-) release, particularly in the case of Deltapor1 mitochondria. We also observed that the effect of the TOM complex blockage on O(2)(*-) release from mitochondria coincided with the levels of O(2)(*-) release as well as with levels of Tom40 expression in the mitochondria. Thus, we conclude that the TOM complex participates in O(2)(*-) release from mitochondria.

  3. Effect of CO2 absorption on ion and water mobility in an anion exchange membrane

    Science.gov (United States)

    Peng, Jing; Roy, Asa L.; Greenbaum, Steve G.; Zawodzinski, Thomas A.

    2018-03-01

    We report the measured water uptake, density, ionic conductivity and water transport properties in Tokuyama A201 membrane in OH-, HCO3- and Cl- forms. The water uptake of the AEM varies with anion type in the order λ(OH-) > λ(HCO3-) > λ(Cl-) for samples equilibrated with the same water vapor activity (aw). The conductivity of the AEM is reduced by absorption of CO2. Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) measurements were utilized to characterize the diffusivity of water and HCO3- ion. The anion diffusion coefficient and membrane conductivity are used to probe the applicability of the Nernst-Einstein equation in these AEMs.

  4. Inhibition of nuclear waste solutions containing multiple aggressive anions

    International Nuclear Information System (INIS)

    Congdon, J.W.

    1987-01-01

    The inhibition of localized corrosion of carbon steel in caustic, high-level radioactive waste solutions was studied using cyclic potentiodynamic polarization scans, supplemented by partially immersed coupon tests. The electrochemical tests provided a rapid and accurate means of determining the relationship between the minimum inhibitor requirements and the concentration of the aggressive anions in this system. Nitrate, sulfate, chloride, and fluoride were identified as aggressive anions, however, no synergistic effects were observed between these anions. This observation may have important theoretical implications because it tends to contradict the behavior of aggressive anions as predicted by existing theories for localized corrosion. 10 refs., 5 figs., 2 tabs

  5. Photoinduced Dynamics of Neutral, Cationic, and Anionic Species

    DEFF Research Database (Denmark)

    Stephansen, Anne Boutrup

    electrons and subsequently transition from dipole to valence-bound anions in different energy regimes. The investigations indicate that dipole-bound anion formation depends strongly on the magnitude of the molecular dipole moment, while the formation and stability of valence-bound anions depends on ring....... Nucleobase anions are posited to be involved in DNA damage, where the molecular dipole moment of a nucleobase acts as electron-antenna and gateway for low-energy electrons to access the valence system of DNA. The investigations presented herein explore the abilities of adenine, thymine, and uracil to capture...

  6. Photoelectron Spectroscopy of 4-Bromochlorobenzene Dimer and Trimer Anions

    International Nuclear Information System (INIS)

    Kim, Namdoo

    2013-01-01

    I investigated the electron attachment to 4-BCB dimer and trimer anions using anion photoelectron spectroscopy and theoretical calculations. I found that an excess electron can be delocalized to these clusters through extended π-network. However, the nature of the ion core is different for the dimer and trimer. For the heterodimer anions, the geometry is determined by the differences in electronegativity of the molecules. Dimer anions with a large electronegativity difference have T-shaped geometries and those with a small electronegativity difference have PD geometries

  7. Comparison between the polypeptide profile of halophilic bacteria and salt tolerant plants.

    Science.gov (United States)

    Muñoz, G; González, C; Flores, P; Prado, B; Campos, V

    1997-12-01

    Changes in the polypeptide profile induced by salt stress in halotolerant and halophilic bacteria, isolated from the Atacama desert (northern Chile), were compared with those in the cotyledons of Prosopis chilensis (Leguminoseae) seedlings, a salt tolerant plant. SDS-PAGE analyses show the presence of four predominant polypeptides, with molecular weights around 78, 70, 60 and 44 kDa respectively, both in bacteria and in cotyledons from P. chilensis seedlings raised under salt stress conditions. Moreover, the 60 and 44 kDa polypeptides seem to be salt responsive, since their concentration increases with increasing NaCl in the growth medium. Our results suggest a common mechanism for salt tolerance in prokaryotes and in eukaryotes.

  8. Polypeptides with quaternary phosphonium side chains: synthesis, characterization, and cell-penetrating properties.

    Science.gov (United States)

    Song, Ziyuan; Zheng, Nan; Ba, Xiaochu; Yin, Lichen; Zhang, Rujing; Ma, Liang; Cheng, Jianjun

    2014-04-14

    Polypeptides bearing quaternary phosphonium side chains were synthesized via controlled ring-opening polymerization of chlorine-functionalized amino acid N-carboxyanhydride monomers followed by one-step nucleophilic substitution reaction with triethylphosphine. The conformation of the resulting polypeptides can be controlled by modulating the side-chain length and α-carbon stereochemistry. The phosphonium-based poly(l-glutamate) derivatives with 11 σ-bond backbone-to-charge distance adopt stable α-helical conformation against pH and ionic strength changes. These helical, quaternary phosphonium-bearing polypeptides exhibit higher cell-penetrating capability than their racemic and random-coiled analogues. They enter cells mainly via an energy-independent, nonendocytic cell membrane transduction mechanism and exhibit low cytotoxicity, substantiating their potential use as a safe and effective cell-penetrating agent.

  9. Effect of oxygen on morphogenesis and polypeptide expression by Mucor racemosus

    International Nuclear Information System (INIS)

    Phillips, G.J.; Borgia, P.T.

    1985-01-01

    The morphology of Mucor racemosus in cultures continuously sparged with nitrogen gas was investigated. When appropriate precautions were taken to prevent oxygen from entering the cultures, the morphology of the cells was uniformly yeastlike irrespective of the N 2 flow rate. When small amounts of oxygen entered the cultures the resulting microaerobic conditions evoked mycelial development. Polypeptides synthesized by aerobic mycelia, microaerobic mycelia, anaerobic yeasts, and yeasts grown in a CO 2 atmosphere were compared by two-dimensional gel electrophoresis. The results indicated that a large number of differences in polypeptide expression exist when microaerobic mycelia or anaerobic yeasts are compared with aerobic mycelia and that these alterations correlate with a change from an oxidative to a fermentative metabolic mode. The authors hypothesize that oxygen regulates the expression of polypeptides involved in both the metabolic mode and in morphogenesis

  10. Analysis of urine composition in type Ⅱ diabetic mice after intervention therapy using holothurian polypeptides

    Science.gov (United States)

    Li, Yanyan; Xu, Jiajie; Su, Xiurong

    2017-07-01

    Hydrolysates and peptide fractions (PF) obtained from sea cucumber with commercial enzyme were studied on the hpyerglycemic and renal protective effects on db/db rats using urine metabolomics. Compared with the control group the polypeptides from the two species could significantly reduce the urine glucose and urea. We also tried to address the compositions of highly expressed urinary proteins using a proteomics approach. They were serum albumins, AMBP proteins, negative trypsin, elastase and urinary protein, GAPDH, a receptor of urokinase-type plasminogen activator (uPAR), and Ig kappa chain C region. We used the electronic nose to quickly detect changes in the volatile substances in mice urine after holothurian polypeptides fed, and the results show it can identify the difference between treatment groups with the control group without overlapping. The protein express mechanism of holothurian polypeptides treating diabetes was discussed, and we suggested these two peptides with the hypoglycemic and renal protective activity might be utilized as nutraceuticals.

  11. The critical relation between chemical stability of cations and water in anion exchange membrane fuel cells environment

    Science.gov (United States)

    Dekel, Dario R.; Willdorf, Sapir; Ash, Uri; Amar, Michal; Pusara, Srdjan; Dhara, Shubhendu; Srebnik, Simcha; Diesendruck, Charles E.

    2018-01-01

    Anion exchange membrane fuel cells can potentially revolutionize energy storage and delivery; however, their commercial development is hampered by a significant technological impedance: the chemical decomposition of the anion exchange membranes during operation. The hydroxide anions, while transported from the cathode to the anode, attack the positively charged functional groups in the polymer membrane, neutralizing it and suppressing its anion-conducting capability. In recent years, several new quaternary ammonium salts have been proposed to address this challenge, but while they perform well in ex-situ chemical studies, their performance is very limited in real fuel cell studies. Here, we use experimental work, corroborated by molecular dynamics modeling to show that water concentration in the environment of the hydroxide anion, as well as temperature, significantly impact its reactivity. We compare different quaternary ammonium salts that have been previously studied and test their stabilities in the presence of relatively low hydroxide concentration in the presence of different amounts of solvating water molecules, as well as different temperatures. Remarkably, with the right amount of water and at low enough temperatures, even quaternary ammonium salts which are considered "unstable", present significantly improved lifetime.

  12. The difference between critical care initiation anion gap and prehospital admission anion gap is predictive of mortality in critical illness.

    Science.gov (United States)

    Lipnick, Michael S; Braun, Andrea B; Cheung, Joyce Ting-Wai; Gibbons, Fiona K; Christopher, Kenneth B

    2013-01-01

    We hypothesized that the delta anion gap defined as difference between critical care initiation standard anion gap and prehospital admission standard anion gap is associated with all cause mortality in the critically ill. Observational cohort study. Two hundred nine medical and surgical intensive care beds in two hospitals in Boston, MA. Eighteen thousand nine hundred eighty-five patients, age ≥18 yrs, who received critical care between 1997 and 2007. The exposure of interest was delta anion gap and categorized a priori as 10 mEq/L. Logistic regression examined death by days 30, 90, and 365 postcritical care initiation and in-hospital mortality. Adjusted odds ratios were estimated by multivariable logistic regression models. The discrimination of delta anion gap for 30-day mortality was evaluated using receiver operator characteristic curves performed for a subset of patients with all laboratory data required to analyze the data via physical chemical principles (n = 664). None. Delta anion gap was a particularly strong predictor of 30-day mortality with a significant risk gradient across delta anion gap quartiles following multivariable adjustment: delta anion gap anion gap 5-10 mEq/L odds ratio 1.56 (95% confidence interval 1.35-1.81; p anion gap >10 mEq/L odds ratio 2.18 (95% confidence interval 1.76-2.71; p anion gap 0-5 mEq/L. Similar significant robust associations post multivariable adjustments are seen with death by days 90 and 365 as well as in-hospital mortality. Correcting for albumin or limiting the cohort to patients with standard anion gap at critical care initiation of 10-18 mEq/L did not materially change the delta anion gap-mortality association. Delta anion gap has similarly moderate discriminative ability for 30-day mortality in comparison to standard base excess and strong ion gap. An increase in standard anion gap at critical care initiation relative to prehospital admission standard anion gap is a predictor of the risk of all cause patient

  13. Hordein polypeptide patterns in relation to malting quality in Brazilian barley varieties

    Directory of Open Access Journals (Sweden)

    Echart-Almeida Cinara

    2001-01-01

    Full Text Available Since there is evidence that malting quality is related to the storage protein (hordein fraction, in the present work the hordein polypeptide patterns from 13 barley (Hordeum vulgare L. varieties of different malting quality were analysed in order to explore the feasibility of using hordein electrophoresis to assist in the selection of malting barleys. The formation of clusters separating the varieties with higher malting quality from the others with lower quality suggests that there is a relationship between the general hordein polypeptide pattern and malting quality in the varieties analysed. By the Sperman's correlation test three hordein bands correlated negatively with malting quality in the germplasm studied.

  14. Phase transition in polypeptides: a step towards the understanding of protein folding

    DEFF Research Database (Denmark)

    Yakubovich, Alexander V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2006-01-01

    We present a formalism which turns out to be very successful in the description of the polypeptide folding. We consider this process as a first-order phase transition and develop a theory which is free of model parameters and is based solely on fundamental physical principles. It describes...... essential thermodynamical properties of the system such as heat capacity, the phase transition temperature and others from the analysis of the polypeptide potential energy surface calculated within ab initio density functional theory and parameterized by two dihedral angles. This problem is viewed...

  15. Protective effect of Cordyceps militaris polypeptide against acute alcoholic liver injury in rats

    Directory of Open Access Journals (Sweden)

    CAI Qi

    2016-04-01

    Full Text Available ObjectiveTo investigate the protective effect of Cordyceps militaris polypeptide against acute alcoholic liver injury in rats and related mechanism. MethodsA total of 60 Wistar rats were randomly divided into blank control group, model group, and low-, medium-, and high-dose Cordyceps militaris polypeptide groups. All rats except those in the blank control group were given 10 ml/kg 56° liquor by gavage once a day; the rats in the blank control group were given distilled water of the same dose by gavage once a day. At 1 hour after gavage with liquor, the rats in the model group and low-, medium-, and high-dose Cordyceps militaris polypeptide groups were given distilled water or Cordyceps militaris polypeptide solution (6 ml/kg by gavage. Blood samples were collected from the orbit 4 weeks later. The serum levels of alanine aminotransferase (ALT and aspartate aminotransferase (AST and the activity of superoxide dismutase (SOD and level of malondialdehyde (MDA in the liver were measured for each group, and the pathological changes in the liver were observed under a light microscope. Analysis of variance was applied for comparison between multiple groups, and the SNK-q test was applied for comparison between any two groups. ResultsCompared with the model group, the low-, medium-, and high-dose Cordyceps militaris polypeptide groups showed significant reductions in the serum levels of ALT and AST and the level of MDA in the liver (all P<0.05, as well as a significant increase in the activity of SOD in the liver (all P<0.05, while these indices showed significant differences between the low-, medium-, and high-dose Cordyceps militaris polypeptide groups (all P<0.05. The liver pathological sections from the low-, medium-, and high-dose Cordyceps militaris polypeptide groups showed alleviated hepatocyte fatty degeneration and necrosis induced by alcohol under a light microscope. ConclusionCordyceps militaris polypeptide has a protective effect

  16. Once upon Anion: A Tale of Photodetachment

    Science.gov (United States)

    Lineberger, W. Carl

    2013-04-01

    This contribution is very much a personal history of a journey through the wonderful world of anion chemistry, and a tale of how advances in laser technologies, theoretical methods, and computational capabilities continuously enabled advances in our understanding. It is a story of the excitement and joy that come from the opportunity to add to the fabric of science, and to do so by working as a group of excited explorers with common goals. The participants in this journey include me, my students and postdoctoral associates, my collaborators, and our many generous colleagues. It all happened, in the words of the Beatles, “with a little help from my friends.” Actually, it was so much more than a little help!

  17. Structural evolution of small ruthenium cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Waldt, Eugen [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Hehn, Anna-Sophia; Ahlrichs, Reinhart [Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany); Kappes, Manfred M.; Schooss, Detlef, E-mail: detlef.schooss@kit.edu [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany)

    2015-01-14

    The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru{sub 8}{sup −}–Ru{sub 12}{sup −} have simple cubic structures, Ru{sub 13}{sup −}–Ru{sub 16}{sup −} form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru{sub 17}{sup −}, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru{sub 18}{sup −}–Ru{sub 20}{sup −}. Our calculations also predict simple cubic structures for the smaller clusters Ru{sub 4}{sup −}–Ru{sub 7}{sup −}, which were not accessible to electron diffraction measurements.

  18. Adsorption of an anionic dispersant on lignite

    Energy Technology Data Exchange (ETDEWEB)

    Yavuz, R.; Kucukbayrak, S. [Istanbul Technical University, Istanbul (Turkey). Dept. of Chemical Engineering, Chemical & Metallurgical Engineering Faculty

    2001-12-01

    Since coal is not a homogeneous substance but a mixture of carbonaceous materials and mineral matter, it has a variety of surface properties. Therefore, it is not easy to control the properties of coal suspensions by simply adjusting variables, such as pH and/or electrolyte. A chemical agent needs to be added to control the properties of the coal suspensions. The adsorption behavior of an anionic dispersant in the presence of a wetting agent using some Turkish lignite samples was investigated. The effects of dispersant concentration, temperature and pH on the dispersant adsorption were studied systematically, and the experimental results are presented. Pellupur B69 as a dispersant, commercial mixture of formaldehyde condensate sodium salt of naphthalene sulphonic acid, and Texapon N{sub 2}5 as a wetting agent, a sodium lauryl ether sulfate, have been used.

  19. Structures and properties of anionic clay minerals

    International Nuclear Information System (INIS)

    Koch, Chr. Bender

    1998-01-01

    The Moessbauer spectra of pyroaurite-sjoegrenite-type compounds (PTC) (layered anion exchangers) are discussed with reference to the crystal structure, cation order, and crystallite morphology. It is shown that cation-ordered layers are produced in the synthesis of carbonate and sulphate types of green rust. In contrast, synthetic and natural pyroaurite only occurs as disordered types. The redox chemistry of Fe(III) within the metal hydroxide layer is illustrated with examples of electrochemical oxidation and reversible reduction by boiling glycerol. The chemistry of iron in the interlayer is exemplified by the intercalation of Fe-cyanide complexes in hydrotalcite. This reaction may be used as a probe for the charge distribution in the interlayer

  20. Anion permselective membrane. [For redox fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, S.S.; Hodgdon, R.B.

    1978-01-01

    Experimental anion permeselective membranes were improved and characterized for use as separators in a chemical redox, power storage cell being developed at the NASA Lewis Research Center. The goal of minimal Fe/sup +3/ ion transfer was achieved for each candidate membrane system. Minimal membrane resistivity was demonstrated by reduction of film thickness using synthetic backing materials but usefulness of thin membranes was limited by the scarcity of compatible fabrics. The most durable and useful backing fabrics were modacrylics. One membrane, a copolymer of 4 vinylpyridine and vinyl benzylchloride was outstanding in overall electrochemical and physical properties. Long term (1000 hrs) membrane chemical and thermal durability in redox environment was shown by three candidate polymers and two membranes. The remainder had good durability at ambient temperature. Manufacturing capability was demonstrated for large scale production of membrane sheets 5.5 ft/sup 2/ in area for two candidate systems.

  1. Diffuse neutron scattering from anion-excess strontium chloride

    DEFF Research Database (Denmark)

    Goff, J.P.; Clausen, K.N.; Fåk, B.

    1992-01-01

    The defect structure and diffusional processes have been studied in the anion-excess fluorite (Sr, Y)Cl2.03 by diffuse neutron scattering techniques. Static cuboctahedral clusters found at ambient temperature break up at temperatures below 1050 K, where the anion disorder is highly dynamic. The a...

  2. Anion gap in hyperproteinaemia: With reference to tuberculosis ...

    African Journals Online (AJOL)

    Objectives: (1)To determine the level of electrolyte in TB patients (2) To see if these are significantly different from those of control-match for age and sex (3) To calculate the anion gap levels in TB patient and (4) to see if the anion gap levels could be used in the management of patient with tuberculosis. Patient and Methods: ...

  3. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Alkaline polymer electrolyte fuel cell; anion exchange membrane; PPO; homogeneous quaterni- zation. 1. Introduction. Presently, alkaline polymer electrolyte fuel cells (APEFCs) using anion exchange membranes have received an immense interest among researchers (Varcoe and Slade. 2005). The advantages of ...

  4. Anion binding by biotin[6]uril in water

    DEFF Research Database (Denmark)

    Lisbjerg, Micke; Nielsen, Bjarne Enrico; Milhøj, Birgitte Olai

    2015-01-01

    In this contribution we show that the newly discovered 6 + 6 biotin-formaldehyde macrocycle Biotin[6]uril binds a variety of anionic guest molecules in water. We discuss how and why the anions are bound based on data obtained using NMR spectroscopy, mass spectrometry, isothermal titration...

  5. Protonation Reaction of Benzonitrile Radical Anion and Absorption of Product

    DEFF Research Database (Denmark)

    Holcman, Jerzy; Sehested, Knud

    1975-01-01

    The rate constant for the protonation of benzonitrile radical anions formed in pulse radiolysis of aqueous benzonitrile solutions is (3.5 ± 0.5)× 1010 dm3 mol–1 s–1. A new 270 nm absorption band is attributed to the protonated benzonitrile anion. The pK of the protonation reaction is determined t...

  6. Decreased anion gap associated with monoclonal and pseudomonoclonal gammopathy.

    Science.gov (United States)

    Frohlich, J.; Adam, W.; Golbey, M. J.; Bernstein, M.

    1976-01-01

    Nine patients with monoclonal and one with pseudomonoclonal gammopathy were found to have a decreased anion gap. Eight of the patients had multiple myeloma, one has plasma cell leukemia and one had chronic active hepatitis. In all of the the decreased anion gap was associated with an increased concentration of IgG greater than 5 g/dl. PMID:1032353

  7. Non-chromatographic purification of recombinant elastin-like polypeptides and their fusions with peptides and proteins from Escherichia coli.

    Science.gov (United States)

    MacEwan, Sarah R; Hassouneh, Wafa; Chilkoti, Ashutosh

    2014-06-09

    Elastin-like polypeptides are repetitive biopolymers that exhibit a lower critical solution temperature phase transition behavior, existing as soluble unimers below a characteristic transition temperature and aggregating into micron-scale coacervates above their transition temperature. The design of elastin-like polypeptides at the genetic level permits precise control of their sequence and length, which dictates their thermal properties. Elastin-like polypeptides are used in a variety of applications including biosensing, tissue engineering, and drug delivery, where the transition temperature and biopolymer architecture of the ELP can be tuned for the specific application of interest. Furthermore, the lower critical solution temperature phase transition behavior of elastin-like polypeptides allows their purification by their thermal response, such that their selective coacervation and resolubilization allows the removal of both soluble and insoluble contaminants following expression in Escherichia coli. This approach can be used for the purification of elastin-like polypeptides alone or as a purification tool for peptide or protein fusions where recombinant peptides or proteins genetically appended to elastin-like polypeptide tags can be purified without chromatography. This protocol describes the purification of elastin-like polypeptides and their peptide or protein fusions and discusses basic characterization techniques to assess the thermal behavior of pure elastin-like polypeptide products.

  8. The interdomain flexible linker of the polypeptide GalNAc transferases dictates their long-range glycosylation preferences

    DEFF Research Database (Denmark)

    Rivas, Matilde De Las; Lira-Navarrete, Erandi; Daniel, Earnest James Paul

    2017-01-01

    The polypeptide GalNAc-transferases (GalNAc-Ts), that initiate mucin-type O-glycosylation, consist of a catalytic and a lectin domain connected by a flexible linker. In addition to recognizing polypeptide sequence, the GalNAc-Ts exhibit unique long-range N- A nd/or C-terminal prior glycosylation ...

  9. Extraction of monoclonal antibodies (IgG1) using anionic and anionic/nonionic reverse micelles.

    Science.gov (United States)

    George, Daliya A; Stuckey, David C

    2010-01-01

    Purification schemes for antibody production based on affinity chromatography are trying to keep pace with increases in cell culture expression levels and many current research initiatives are focused on finding alternatives to chromatography for the purification of Monoclonal antibodies (MAbs). In this article, we have investigated an alternative separation technique based on liquid-liquid extraction called the reverse micellar extraction. We extracted MAb (IgG1) using reverse micelles of an anionic surfactant, sodium bis 2-ethyl-hexyl sulfosuccinate (AOT) and a combination of anionic (AOT) and nonionic surfactants (Brij-30, Tween-85, Span-85) using isooctane as the solvent system. The extraction efficiency of IgG1 was studied by varying parameters, such as pH of the aqueous phase, cation concentration, and type and surfactant concentration. Using the AOT/Isooctane reverse micellar system, we could achieve good overall extraction of IgG1 (between 80 and 90%), but only 30% of the bioactivity of IgG1 could be recovered at the end of the extraction by using its binding to affinity chromatography columns as a surrogate measure of activity. As anionic surfactants were suspected as being one of the reasons for the reduced activity, we decided to combine a nonionic surfactant with an anionic surfactant and then study its effect on the extraction efficiency and bioactivity. The best results were obtained using an AOT/Brij-30/Isooctane reverse micellar system, which gave an overall extraction above 90 and 59% overall activity recovery. An AOT/Tween-85/Isooctane reverse micellar system gave an overall extraction of between 75 and 80% and overall activity recovery of around 40-45%. The results showed that the activity recovery of IgG1 can be significantly enhanced using different surfactant combination systems, and if the recovery of IgG1 can be further enhanced, the technique shows considerable promise for the downstream purification of MAbs. © 2010 American Institute of

  10. Coumarin amide derivatives as fluorescence chemosensors for cyanide anions

    International Nuclear Information System (INIS)

    Wu, Qianqian; Liu, Zhiqiang; Cao, Duxia; Guan, Ruifang; Wang, Kangnan; Shan, Yanyan; Xu, Yongxiao; Ma, Lin

    2015-01-01

    Four coumarin amide derivatives with 4-methyl coumarin or pyrene as terminal group have been synthesized. Their photophysical properties and recognition properties for cyanide anions have been examined. The results indicate that the compounds can recognize cyanide anions with obvious absorption and fluorescence spectra change, at the same time, obvious color and fluorescence change can be observed by naked eye. The in situ hydrogen nuclear magnetic resonance spectra and photophysical properties change confirm that Michael additions between the chemosensors and cyanide anions take place at the 4-position of coumarin. - Highlights: • Four coumarin amide derivatives with 4-methyl coumarin or pyrene as terminal group were synthesized. • The compounds can recognize cyanide anions with obvious absorption and fluorescence spectra change. • Michael additions between the chemosensors and cyanide anions take place at the 4-position of coumarin

  11. Antipeptide antibodies that can distinguish specific subunit polypeptides of glutamine synthetase from bean (Phaseolus vulgaris L.)

    Science.gov (United States)

    Cai, X.; Henry, R. L.; Takemoto, L. J.; Guikema, J. A.; Wong, P. P.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    The amino acid sequences of the beta and gamma subunit polypeptides of glutamine synthetase from bean (Phaseolus vulgaris L.) root nodules are very similar. However, there are small regions within the sequences that are significantly different between the two polypeptides. The sequences between amino acids 2 and 9 and between 264 and 274 are examples. Three peptides (gamma 2-9, gamma 264-274, and beta 264-274) corresponding to these sequences were synthesized. Antibodies against these peptides were raised in rabbits and purified with corresponding peptide-Sepharose affinity chromatography. Western blot analysis of polyacrylamide gel electrophoresis of bean nodule proteins demonstrated that the anti-beta 264-274 antibodies reacted specifically with the beta polypeptide and the anti-gamma 264-274 and anti-gamma 2-9 antibodies reacted specifically with the gamma polypeptide of the native and denatured glutamine synthetase. These results showed the feasibility of using synthetic peptides in developing antibodies that are capable of distinguishing proteins with similar primary structures.

  12. Effects on DPPH inhibition of egg-white protein polypeptides treated by pulsed electric field technology.

    Science.gov (United States)

    Wang, Ke; Wang, Jia; Liu, Bolong; Lin, Songyi; Zhao, Ping; Liu, Jingbo; Jones, Gregory; Huang, Hsiang-Chi

    2013-05-01

    Egg-white protein polypeptides are potentially used as a functional ingredient in food products. In this study, the effects on DPPH inhibition of egg-white protein polypeptides ranging from 10 to 30 kDa treated by pulsed electric field (PEF) technology were investigated. 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) inhibition (%) was used to evaluate the antioxidant activity of polypeptides. In order to develop and optimize a pulsed electric field (PEF) mathematical model for improving the antioxidant activity, we have investigated three variables, including concentration (6, 8 and 10 mg mL(-1)), electric field intensity (10, 20 and 30 kV cm(-1)) and pulse frequency (2000, 2350 and 2700 Hz) and subsequently optimized them by response surface methodology (RSM). The concentration (8 mg mL(-1)), electric field intensity (10 kV cm(-1)) and pulse frequency (2000 Hz) were found to be the optimal conditions under which the DPPH inhibition increased 28.44%, compared to the sample without PEF treatment. Both near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyze the change of functional groups. The results showed that PEF technology could improve the antioxidant activity of antioxidant polypeptides from egg-white protein under the optimized conditions. © 2012 Society of Chemical Industry.

  13. Noncanonical self-assembly of highly asymmetric genetically encoded polypeptide amphiphiles into cylindrical micelles.

    Science.gov (United States)

    McDaniel, Jonathan R; Weitzhandler, Isaac; Prevost, Sylvain; Vargo, Kevin B; Appavou, Marie-Sousai; Hammer, Daniel A; Gradzielski, Michael; Chilkoti, Ashutosh

    2014-11-12

    Elastin-like polypeptides (ELPs) are a class of biopolymers consisting of the pentameric repeat (VPGαG)n based on the sequence of mammalian tropoelastin that display a thermally induced soluble-to-insoluble phase transition in aqueous solution. We have discovered a remarkably simple approach to driving the spontaneous self-assembly of high molecular weight ELPs into nanostructures by genetically fusing a short 1.5 kDa (XGy)z assembly domain to one end of the ELP. Classical theories of self-assembly based on the geometric mass balance of hydrophilic and hydrophobic block copolymers suggest that these highly asymmetric polypeptides should form spherical micelles. Surprisingly, when sufficiently hydrophobic amino acids (X) are presented in a periodic sequence such as (FGG)8 or (YG)8, these highly asymmetric polypeptides self-assemble into cylindrical micelles whose length can be tuned by the sequence of the morphogenic tag. These nanostructures were characterized by light scattering, tunable resistive pulse sensing, fluorescence spectrophotometry, and thermal turbidimetry, as well as by cryogenic transmission electron microscopy (cryo-TEM) and small-angle neutron scattering (SANS). These short assembly domains provide a facile strategy to control the size, shape, and stability of stimuli responsive polypeptide nanostructures.

  14. Identification of flagellar and associated polypeptides of Helicobacter (formerly Campylobacter) pylori.

    Science.gov (United States)

    Luke, C J; Kubiak, E; Cockayne, A; Elliott, T S; Penn, C W

    1990-09-01

    Flagella of Helicobacter pylori were isolated from intact organisms by shearing and differential centrifugation. Treatment of the flagella with the detergent Triton X-100 removed the flagellar sheath, which was confirmed by electron microscopy, and the remaining naked flagella were shown by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to consist primarily of a single 54 kilodalton (kDa) polypeptide. This was confirmed by immunogold labelling and electron microscopy of detergent treated whole organisms, using a mouse antiserum specific for the 54 kDa polypeptide. Polypeptides solubilised from crude flagellar preparations by detergent treatment were found to have molecular weights of 26, 30, 58, 62, 66 and 80 kDa. These polypeptides are possible components of the flagellar sheath and they may represent outer membrane proteins, based on the assumption that the flagellar sheath is related in composition to the outer membrane of the organism. Analysis and definition of these components of the surface structures of the organism are important in understanding the interaction between the organism and its host in pathogenesis.

  15. Structural variation and inhibitor binding in polypeptide deformylase from four different bacterial species.

    Science.gov (United States)

    Smith, Kathrine J; Petit, Chantal M; Aubart, Kelly; Smyth, Martin; McManus, Edward; Jones, Jo; Fosberry, Andrew; Lewis, Ceri; Lonetto, Michael; Christensen, Siegfried B

    2003-02-01

    Polypeptide deformylase (PDF) catalyzes the deformylation of polypeptide chains in bacteria. It is essential for bacterial cell viability and is a potential antibacterial drug target. Here, we report the crystal structures of polypeptide deformylase from four different species of bacteria: Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Escherichia coli. Comparison of these four structures reveals significant overall differences between the two Gram-negative species (E. coli and H. influenzae) and the two Gram-positive species (S. pneumoniae and S. aureus). Despite these differences and low overall sequence identity, the S1' pocket of PDF is well conserved among the four enzymes studied. We also describe the binding of nonpeptidic inhibitor molecules SB-485345, SB-543668, and SB-505684 to both S. pneumoniae and E. coli PDF. Comparison of these structures shows similar binding interactions with both Gram-negative and Gram-positive species. Understanding the similarities and subtle differences in active site structure between species will help to design broad-spectrum polypeptide deformylase inhibitor molecules.

  16. ca 15-3, ceruloplasmin and tissue polypeptide specific antigen as a ...

    African Journals Online (AJOL)

    hi-tech

    2000-06-01

    Jun 1, 2000 ... CA 15-3, CERULOPLASMIN AND TISSUE POLYPEPTIDE SPECIFIC ANTIGEN AS A TUMOUR MARKER PANEL IN BREAST CANCER. Ö. Özyilkan ... The most commonly used breast cancer antigen is CA 15-3. Objective: ..... circulation CA 15-3 and carcinoembryonic antigen levels in patients with breast ...

  17. TISSUE POLYPEPTIDE-SPECIFIC ANTIGEN - A DISCRIMINATIVE PARAMETER BETWEEN PROSTATE-CANCER AND BENIGN PROSTATIC HYPERTROPHY

    NARCIS (Netherlands)

    MARRINK, J; OOSTEROM, R; BONFRER, HMG; SCHRODER, FH; MENSINK, HJA

    1993-01-01

    The serum concentration of the cell proliferation marker TPS (tissue polypeptide-specific antigen) was compared with the tumour marker PSA (prostate specific antigen). PSA was found elevated in 50% of the benign prostatic hypertrophy (BPH) patients, in 88% of the patients with active prostate cancer

  18. Postnatally disturbed pancreatic islet cell distribution in human islet amyloid polypeptide transgenic mice

    NARCIS (Netherlands)

    Wong, HY; Ahren, B; Lips, CJM; Hoppener, JWM; Sundler, F

    2003-01-01

    Objective: Islet amyloid polypeptide (IAPP)/amylin is produced by the pancreatic islet beta-cells, which also produce insulin. To study potential functions of IAPP, we have generated transgenic mice overexpressing human IAPP (hIAPP) in the beta-cells. These mice show a diabetic phenotype when

  19. Creating cellular patterns using genetically engineered, gold- and cell-binding polypeptides.

    Science.gov (United States)

    Li, Linying; Mo, Chia-Kuei; Chilkoti, Ashutosh; Lopez, Gabriel P; Carroll, Nick J

    2016-06-27

    Patterning cells on material surfaces is an important tool for the study of fundamental cell biology, tissue engineering, and cell-based bioassays. Here, the authors report a simple approach to pattern cells on gold patterned silicon substrates with high precision, fidelity, and stability. Cell patterning is achieved by exploiting adsorbed biopolymer orientation to either enhance (gold regions) or impede (silicon oxide regions) cell adhesion at particular locations on the patterned surface. Genetic incorporation of gold binding domains enables C-terminal chemisorption of polypeptides onto gold regions with enhanced accessibility of N-terminal cell binding domains. In contrast, the orientation of polypeptides adsorbed on the silicon oxide regions limit the accessibility of the cell binding domains. The dissimilar accessibility of cell binding domains on the gold and silicon oxide regions directs the cell adhesion in a spatially controlled manner in serum-free medium, leading to the formation of well-defined cellular patterns. The cells are confined within the polypeptide-modified gold regions and are viable for eight weeks, suggesting that bioactive polypeptide modified surfaces are suitable for long-term maintenance of patterned cells. This study demonstrates an innovative surface-engineering approach for cell patterning by exploiting distinct ligand accessibility on heterogeneous surfaces.

  20. Circulating endogenous vasoactive intestinal polypeptide (VIP) in patients with uraemia and liver cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Staun-Olsen, P; Borg Mogensen, N

    1986-01-01

    The concentration of vasoactive intestinal polypeptide (VIP) in peripheral venous plasma was median 6.0 pmol l-1 (range 0-20) in 112 normal subjects. In fifty-three patients with decreased kidney function plasma VIP was significantly increased (median 15.0 pmol l-1, range 0.5-70, P less than 0...