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Sample records for aspartic acid-rich peptides

  1. Surface aggregation of urinary proteins and aspartic acid-rich peptides on the faces of calcium oxalate monohydrate investigated by in situ force microscopy

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    Weaver, M L; Qiu, S R; Hoyer, J R; Casey, W H; Nancollas, G H; De Yoreo, J J

    2008-05-28

    The growth of calcium oxalate monohydrate in the presence of Tamm-Horsfall protein (THP), osteopontin (OPN), and the 27-residue synthetic peptides (DDDS){sub 6}DDD and (DDDG){sub 6}DDD [where D = aspartic acid and X = S (serine) or G (glycine)] was investigated via in situ atomic force microscopy (AFM). The results show that these three growth modulators create extensive deposits on the crystal faces. Depending on the modulator and crystal face, these deposits can occur as discrete aggregates, filamentary structures, or uniform coatings. These proteinaceous films can lead to either the inhibition or increase of the step speeds (with respect to the impurity-free system) depending on a range of factors that include peptide or protein concentration, supersaturation and ionic strength. While THP and the linear peptides act, respectively, to exclusively increase and inhibit growth on the (-101) face, both exhibit dual functionality on the (010) face, inhibiting growth at low supersaturation or high modulator concentration and accelerating growth at high supersaturation or low modulator concentration. Based on analyses of growth morphologies and dependencies of step speeds on supersaturation and protein or peptide concentration, we argue for a picture of growth modulation that accounts for the observations in terms of the strength of binding to the surfaces and steps and the interplay of electrostatic and solvent-induced forces at crystal surface.

  2. Effect of a single aspartate on helix stability at different positions in a neutral alanine-based peptide.

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    Huyghues-Despointes, B. M.; Scholtz, J. M.; Baldwin, R. L.

    1993-01-01

    A single aspartate residue has been placed at various positions in individual peptides for which the alanine-based reference peptide is electrically neutral, and the helix contents of the peptides have been measured by circular dichroism. The dependence of peptide helix content on aspartate position has been used to determine the helix propensity (s-value). Both the charged (Asp-) and uncharged (Asp0) forms of the aspartate residue are strong helix breakers and have identical s-values of 0.29...

  3. Potential antioxidant peptides produced from whey hydrolysis with an immobilized aspartic protease from Salpichroa origanifolia fruits.

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    Rocha, Gabriela Fernanda; Kise, Francisco; Rosso, Adriana Mabel; Parisi, Mónica Graciela

    2017-12-15

    An aspartic protease from Salpichroa origanifolia fruits was successfully immobilized onto an activated support of glutaraldehyde agarose. The immobilized enzyme presented higher thermal stability than the free enzyme from 40°C to 50°C and high reusability, retaining 54% of the initial activity after ten cycles of the process. Whey protein concentrates (WPC) were hydrolyzed with both free and immobilized enzyme, reaching a similar degree of hydrolysis of approximately 6-8% after 20h. In addition, the immobilized derivate hydrolyzed α-lactalbumin protein with a higher affinity than β-lactoglobulin. The hydrolysate was ultra-filtrated, and the fractions were evaluated for antioxidant activities with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity method. The fraction containing peptides with a molecular mass below 3kDa demonstrated a strong radical quenching effect (IC50: 0.48mg/ml). These results suggest that hydrolyzed WPC could be considered as a promising source of natural food antioxidants for the development of functional food. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Antagonist properties of Conus parius peptides on N-methyl-D-aspartate receptors and their effects on CREB signaling.

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    Shailaja Kunda

    Full Text Available Three members of a family of small neurotoxic peptides from the venom of Conus parius, conantokins (Con Pr1, Pr2, and Pr3, function as antagonists of N-methyl-D-aspartate receptors (NMDAR. We report structural characterizations of these synthetic peptides, and also demonstrate their antagonistic properties toward ion flow through NMDAR ion channels in primary neurons. ConPr1 and ConPr2 displayed moderate increases in α-helicity after addition of Mg(2+. Native apo-ConPr3 possessed an α-helical conformation, and the helicity increased only slightly on addition of Mg(2+. Additionally, these peptides diminished NMDA/Gly-mediated currents and intracellular Ca(2+ (iCa(2+ influx in mature rat primary hippocampal neurons. Electrophysiological data showed that these peptides displayed slower antagonistic properties toward the NMDAR than conantokins from other species of cone snails, e.g., ConT and ConG. Furthermore, to demonstrate selectivity of the C. parius-derived conantokins towards specific NMDAR subunits, cortical neurons from GluN2A(-/- and GluN2B(-/- mice were utilized. Robust inhibition of NMDAR-mediated stimulation in GluN2A(-/--derived mouse neurons, as compared to those isolated from GluN2B(-/--mouse brains, was observed, suggesting a greater selectivity of these antagonists towards the GluN2B subunit. These C. parius conantokins mildly inhibited NMDAR-induced phosphorylation of CREB at Ser(133, suggesting that the peptides modulated iCa(2+ entry and, thereby, activation of CREB, a transcription factor that is required for maintaining long-term synaptic activity. Our data mechanistically show that while these peptides effectively antagonize NMDAR-directed current and iCa(2+ influx, receptor-coupled CREB signaling is maintained. The consequence of sustained CREB signaling is improved neuronal plasticity and survival during neuropathologies.

  5. Antagonist properties of Conus parius peptides on N-methyl-D-aspartate receptors and their effects on CREB signaling.

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    Kunda, Shailaja; Cheriyan, John; Hur, Michael; Balsara, Rashna D; Castellino, Francis J

    2013-01-01

    Three members of a family of small neurotoxic peptides from the venom of Conus parius, conantokins (Con) Pr1, Pr2, and Pr3, function as antagonists of N-methyl-D-aspartate receptors (NMDAR). We report structural characterizations of these synthetic peptides, and also demonstrate their antagonistic properties toward ion flow through NMDAR ion channels in primary neurons. ConPr1 and ConPr2 displayed moderate increases in α-helicity after addition of Mg(2+). Native apo-ConPr3 possessed an α-helical conformation, and the helicity increased only slightly on addition of Mg(2+). Additionally, these peptides diminished NMDA/Gly-mediated currents and intracellular Ca(2+) (iCa(2+)) influx in mature rat primary hippocampal neurons. Electrophysiological data showed that these peptides displayed slower antagonistic properties toward the NMDAR than conantokins from other species of cone snails, e.g., ConT and ConG. Furthermore, to demonstrate selectivity of the C. parius-derived conantokins towards specific NMDAR subunits, cortical neurons from GluN2A(-/-) and GluN2B(-/-) mice were utilized. Robust inhibition of NMDAR-mediated stimulation in GluN2A(-/-)-derived mouse neurons, as compared to those isolated from GluN2B(-/-)-mouse brains, was observed, suggesting a greater selectivity of these antagonists towards the GluN2B subunit. These C. parius conantokins mildly inhibited NMDAR-induced phosphorylation of CREB at Ser(133), suggesting that the peptides modulated iCa(2+) entry and, thereby, activation of CREB, a transcription factor that is required for maintaining long-term synaptic activity. Our data mechanistically show that while these peptides effectively antagonize NMDAR-directed current and iCa(2+) influx, receptor-coupled CREB signaling is maintained. The consequence of sustained CREB signaling is improved neuronal plasticity and survival during neuropathologies.

  6. Development of novel radiogallium-labeled bone imaging agents using oligo-aspartic acid peptides as carriers.

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    Kazuma Ogawa

    Full Text Available (68Ga (T 1/2 = 68 min, a generator-produced nuclide has great potential as a radionuclide for clinical positron emission tomography (PET. Because poly-glutamic and poly-aspartic acids have high affinity for hydroxyapatite, to develop new bone targeting (68Ga-labeled bone imaging agents for PET, we used 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA as a chelating site and conjugated aspartic acid peptides of varying lengths. Subsequently, we compared Ga complexes, Ga-DOTA-(Aspn (n = 2, 5, 8, 11, or 14 with easy-to-handle (67Ga, with the previously described (67Ga-DOTA complex conjugated bisphosphonate, (67Ga-DOTA-Bn-SCN-HBP. After synthesizing DOTA-(Aspn by a Fmoc-based solid-phase method, complexes were formed with (67Ga, resulting in (67Ga-DOTA-(Aspn with a radiochemical purity of over 95% after HPLC purification. In hydroxyapatite binding assays, the binding rate of (67Ga-DOTA-(Aspn increased with the increase in the length of the conjugated aspartate peptide. Moreover, in biodistribution experiments, (67Ga-DOTA-(Asp8, (67Ga-DOTA-(Asp11, and (67Ga-DOTA-(Asp14 showed high accumulation in bone (10.5 ± 1.5, 15.1 ± 2.6, and 12.8 ± 1.7% ID/g, respectively but were barely observed in other tissues at 60 min after injection. Although bone accumulation of (67Ga-DOTA-(Aspn was lower than that of (67Ga-DOTA-Bn-SCN-HBP, blood clearance of (67Ga-DOTA-(Aspn was more rapid. Accordingly, the bone/blood ratios of (67Ga-DOTA-(Asp11 and (67Ga-DOTA-(Asp14 were comparable with those of (67Ga-DOTA-Bn-SCN-HBP. In conclusion, these data provide useful insights into the drug design of (68Ga-PET tracers for the diagnosis of bone disorders, such as bone metastases.

  7. Cyclic arginine-glycine-aspartate peptides enhance three-dimensional stem cell osteogenic differentiation.

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    Hsiong, Susan X; Boontheekul, Tanyarut; Huebsch, Nathaniel; Mooney, David J

    2009-02-01

    The role of morphogens in bone regeneration has been widely studied, whereas the effect of matrix cues, particularly on stem cell differentiation, are less well understood. In this work, we investigated the effects of arginine-glycine-aspartate (RGD) ligand conformation (linear vs cyclic RGD) on primary human bone marrow stromal cell (hBMSC) and D1 stem cell osteogenic differentiation in three-dimensional (3D) culture and compared their response with that of committed MC3T3-E1 preosteoblasts to determine whether the stage of cell differentiation altered the response to the adhesion ligands. Linear RGD densities that promoted osteogenic differentiation of committed cells (MC3T3-E1 preosteoblasts) did not induce differentiation of hBMSCs or D1 stem cells, although matrices presenting the cyclic form of this adhesion ligand enhanced osteoprogenitor differentiation in 3D culture. This may be due to enhanced integrin-ligand binding. These studies indicate that biomaterial design parameters optimized for differentiated cell types may not directly translate to stem cell populations, because less-committed cells may require more instruction than differentiated cells. It is likely that design of synthetic extracellular matrices tailored to promote stem cell differentiation may enhance bone regeneration by transplanted cells.

  8. Poly aspartic acid peptide-linked PLGA based nanoscale particles: potential for bone-targeting drug delivery applications.

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    Jiang, Tao; Yu, Xiaohua; Carbone, Erica J; Nelson, Clarke; Kan, Ho Man; Lo, Kevin W-H

    2014-11-20

    Delivering drugs specifically to bone tissue is very challenging due to the architecture and structure of bone tissue. Poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs) hold great promise for the delivery of therapeutics to bone tissue. The goal of the present research was to formulate a PLGA-based NP drug delivery system for bone tissue exclusively. Since poly-aspartic acids (poly-Asp) peptide sequence has been shown to bind to hydroxyapatite (HA), and has been suggested as a molecular tool for bone-targeting applications, we fabricated PLGA-based NPs linked with poly-Asp peptide sequence. Nanoparticles made of methoxy - poly(ethylene glycol) (PEG)-PLGA and maleimide-PEG-PLGA were prepared using a water-in-oil-in-water double emulsion and solvent evaporation method. Fluorescein isothiocyanate (FITC)-tagged poly-Asp peptide was conjugated to the surface of the nanoparticles via the alkylation reaction between the sulfhydryl groups at the N-terminal of the peptide and the CC double bond of maleimide at one end of the polymer chain to form thioether bonds. The conjugation of FITC-tagged poly-Asp peptide to PLGA NPs was confirmed by NMR analysis and fluorescent microscopy. The developed nanoparticle system is highly aqueous dispersible with an average particle size of ∼80 nm. In vitro binding analyses demonstrated that FITC-poly-Asp NPs were able to bind to HA gel as well as to mineralized matrices produced by human mesenchymal stem cells and mouse bone marrow stromal cells. Using a confocal microscopy technique, an ex vivo binding study of mouse major organ ground sections revealed that the FITC-poly-Asp NPs were able to bind specifically to the bone tissue. In addition, proliferation studies indicated that our FITC-poly-Asp NPs did not induce cytotoxicity to human osteoblast-like MG63 cell lines. Altogether, these promising results indicated that this nanoscale targeting system was able to bind to bone tissue specifically and might have a great

  9. Arginine–glycine–aspartic acid (RGD)-containing peptides inhibit the force production of mouse papillary muscle bundles via α5β1 integrin

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    Sarin, Vandana; Gaffin, Robert D; Meininger, Gerald A; Muthuchamy, Mariappan

    2005-01-01

    Integrins are considered to be an important mechanosensor in cardiac myocytes. To test whether integrins can influence cardiac contractile function, the force–frequency relationships of mouse papillary muscle bundles were measured in the presence or absence of a synthetic integrin-binding peptide, GRGDNP (gly–arg–gly–asp–asn–pro). Results demonstrate that in the presence of an arginine–glycine–aspartic acid (RGD)-containing synthetic peptide, contractile force was depressed significantly by, 28% at 4 Hz, 37.7% at 5 Hz and 20% at 10 Hz (n = 6, P < 0.01). Treatment of myofibres with either protease-generated fragments of denatured collagen (Type I) or denatured collagen that contain the RGD motif, also reduced force production significantly. An integrin-activating antibody for β1 integrin inhibited the force similar to synthetic RGD peptide. Function-blocking integrin antibodies for α5 and β1 integrins reversed the effect of the RGD-containing peptide, and α5 integrin also reversed the effect of proteolytic fragments of denatured collagen on contractile force, whereas experiments with function-blocking antibody for β3 integrin did not reverse the effect of RGD peptide. Force–[Ca2+]i measurements showed that the depressed rate of force generation observed in the presence of the RGD-containing peptide was associated with reduced [Ca2+]i. Data analyses further demonstrated that force per unit of Ca2+ was reduced, suggesting that the myofilament activation process was altered. In addition, inhibition of PKC enzyme using the selective, cell-permeable inhibitor Ro-32-0432, reversed the activity of RGD peptide on papillary muscle bundles. In conclusion, these data indicate that RGD peptide, acting via α5β1 integrin, depresses the force production from papillary muscle bundles, partly associated with changes in [Ca2+]i and the myofilament activation processes, that is modulated by PKCε. PMID:15718258

  10. Inhibition of proliferative and invasive capacities of breast cancer cells by arginine-glycine-aspartic acid peptide in vitro.

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    Yang, Wanhua; Meng, Li; Wang, Hui; Chen, Rui; Wang, Rui; Ma, Xiangyi; Xu, Gang; Zhou, Jianfeng; Wang, Shixuan; Lu, Yunping; Ma, Ding

    2006-01-01

    The Arg-Gly-Asp (RGD) sequence was selected by using phage-display peptides to target tumors, focusing on targeting alpha(v) integrins in tumor blood vessels. Recent studies suggest that peptides containing the RGD sequence can bind to tumor cells, as well as tumor endothelial cells. To investigate whether the RGD peptide has other effects on tumor cells expressing alpha(v) integrins, besides its tumor targeting capability, we designed and synthesized a 10-amino peptide that contained the RGD sequence in a cyclic conformation with a disulfide bond, which specifically bound to breast cancer cell lines MDA-MB-231 and MCF-7. We found that this RGD peptide, GCGGRGDGGC, inhibited tumor cell proliferation in a dose-dependent manner, and also induced apoptosis and G1-phase cell cycle arrest in both of the cell lines that bound and internalized the peptide. Normal ovarian epithelial cells, which did not bind the RGD peptide, were unaffected. RGD peptide treatment also reduced cell invasiveness in both cell lines in vitro. This study suggests that the RGD peptide not only possesses tumor targeting capacity, but also has direct tumor cytotoxic and invasiveness inhibition effects dependent on the blockage of alpha(v) integrin activity, which would make it more efficient in tumor targeting therapy.

  11. Observation of the side chain O-methylation of glutamic acid or aspartic acid containing model peptides by electrospray ionization-mass spectrometry.

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    Atik, A Emin; Guray, Melda Z; Yalcin, Talat

    2017-03-15

    O-methylation of the side chains of glutamic acid (E) and aspartic acid (D) residues is generally observed modification when an acidified methanol/water (MeOH/dH2O) mixture is used as a solvent system during sample preparation for proteomic research. This chemical modification may result misidentification with endogenous protein methylation; therefore, a special care should be taken during sample handling prior to mass spectrometric analysis. In the current study, we systematically examined the extent of E/D methylation and C-terminus carboxyl group of synthetic model peptides in terms of different incubation temperatures, storage times, and added acid types as well as its percentages. To monitor these effects, C-terminus amidated and free acid forms of synthetic model peptides comprised of E or D residue(s) have been analyzed by electrospray ionization-mass spectrometry (ESI-MS). Additionally, LC-MS/MS experiments were performed to confirm the formation of methylated peptide product. The results showed that the rate of methylation was increased as the temperature increases along with prolong incubation times. Moreover, the extent of methylation was remarkably high when formic acid (FA) used as a protonation agent instead of acetic acid (AA). In addition, it was found that the degree of methylation was significantly decreased by lowering acid percentages in ESI solution. More than one acidic residue containing model peptides have been also used to explore the extent of multiple methylation reaction. Lastly, the ethanol (EtOH) and isopropanol (iPrOH) have been substituted separately with MeOH in sample preparation step to investigate the extent of esterification reaction under the same experimental conditions. However, in the positive perspective of view, this method can be used as a simple, rapid and cheap method for methylation of acidic residues under normal laboratory conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Release of biologically active kinin peptides, Met-Lys-bradykinin and Leu-Met-Lys-bradykinin from human kininogens by two major secreted aspartic proteases of Candida parapsilosis.

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    Bras, Grazyna; Bochenska, Oliwia; Rapala-Kozik, Maria; Guevara-Lora, Ibeth; Faussner, Alexander; Kamysz, Wojciech; Kozik, Andrzej

    2013-10-01

    In terms of infection incidence, the yeast Candida parapsilosis is the second after Candida albicans as causative agent of candidiases in humans. The major virulence factors of C. parapsilosis are secreted aspartic proteases (SAPPs) which help the pathogen to disseminate, acquire nutrients and dysregulate the mechanisms of innate immunity of the host. In the current work we characterized the action of two major extracellular proteases of C. parapsilosis, SAPP1 and SAPP2, on human kininogens, proteinaceous precursors of vasoactive and proinflammatory bradykinin-related peptides, collectively called the kinins. The kininogens, preferably the form with lower molecular mass, were effectively cleaved by SAPPs, with the release of two uncommon kinins, Met-Lys-bradykinin and Leu-Met-Lys-bradykinin. While optimal at acidic pH (4-5), the kinin release yield was only 2-3-fold lower at neutral pH. These peptides were able to interact with cellular kinin receptors of B2 subtype and to stimulate the human endothelial cells HMEC-1 to increased secretion of proinflammatory interleukins (ILs), IL-1β and IL-6. The analysis of the stability of SAPP-generated kinins in plasma suggested that they are biologically equivalent to bradykinin, the best agonist of B2 receptor subtype and can be quickly converted to des-Arg(9)-bradykinin, the agonist of inflammation-inducible B1 receptors. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Preparation and evaluation of {sup 99m}Tc-labeled cyclic arginine-glycine-aspartate (RGD) peptide for integrin targeting

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    Lee, Dong-Eun; Hong, Young-Don; Choi, Kang-Hyuk; Lee, So-Young; Park, Pil-Hoon [Radioisotope Research Division, Basic Science and Technology Department, Korea Atomic Energy Research Institute (KAERI), Daejon 305-353 (Korea, Republic of); Choi, Sun-Ju, E-mail: choisj@kaeri.re.k [Radioisotope Research Division, Basic Science and Technology Department, Korea Atomic Energy Research Institute (KAERI), Daejon 305-353 (Korea, Republic of)

    2010-10-15

    Technetium coordination chemistry has been a subject of interest in the development of radiopharmaceuticals, especially imaging radiotracers. Due to the extensive work done on developing chelates for {sup 99m}Tc, various chelators have been investigated and applied to radiopharmceuticals. Previous studies on the coordination chemistry of the [{sup 99m}Tc=O] core have established peptide-derived sequences as effective chelating ligands. These observations led to the design of tetradentate ligands derived from amino acid sequences. Such amino acid sequences provide a tetradentate coordination site for chelation to the radionuclide and an effective functional group for conjugation to biomolecules using conventional solid-phase synthetic routes. A derivative of a novel tripeptide chelating sequence, Pro-Gly-Cys (PGC) has been developed where it is possible to form stable technetium complexes with the [{sup 99m}Tc=O] via N{sub 3}S{sub 1} tetradentate coordination core that serves this function and can be readily incorporated into biomolecules using solid-phase synthesis techniques. As a model system, the RGD peptide was selected which has been well known to target the integrin receptor for angiogenesis and tumor imaging agents. The results of in vivo studies with these novel radiolabeled compounds in tumor xenografts demonstrated a distribution in tumor targeting and other organs, such as kidney, liver and intestines.

  14. Comparisons with amyloid-β reveal an aspartate residue that stabilizes fibrils of the aortic amyloid peptide medin.

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    Davies, Hannah A; Madine, Jillian; Middleton, David A

    2015-03-20

    Aortic medial amyloid (AMA) is the most common localized human amyloid, occurring in virtually all of the Caucasian population over the age of 50. The main protein component of AMA, medin, readily assembles into amyloid-like fibrils in vitro. Despite the prevalence of AMA, little is known about the self-assembly mechanism of medin or the molecular architecture of the fibrils. The amino acid sequence of medin is strikingly similar to the sequence of the Alzheimer disease (AD) amyloid-β (Aβ) polypeptides around the structural turn region of Aβ, where mutations associated with familial, early onset AD, have been identified. Asp(25) and Lys(30) of medin align with residues Asp(23) and Lys(28) of Aβ, which are known to form a stabilizing salt bridge in some fibril morphologies. Here we show that substituting Asp(25) of medin with asparagine (D25N) impedes assembly into fibrils and stabilizes non-cytotoxic oligomers. Wild-type medin, by contrast, aggregates into β-sheet-rich amyloid-like fibrils within 50 h. A structural analysis of wild-type fibrils by solid-state NMR suggests a molecular repeat unit comprising at least two extended β-strands, separated by a turn stabilized by a Asp(25)-Lys(30) salt bridge. We propose that Asp(25) drives the assembly of medin by stabilizing the fibrillar conformation of the peptide and is thus reminiscent of the influence of Asp(23) on the aggregation of Aβ. Pharmacological comparisons of wild-type medin and D25N will help to ascertain the pathological significance of this poorly understood protein. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Optical imaging of head and neck squamous cell carcinoma in vivo using arginine-glycine- aspartic acid peptide conjugated near-infrared quantum dots

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    Huang H

    2013-12-01

    Full Text Available Hao Huang, Yun-Long Bai, Kai Yang, Hong Tang, You-Wei WangDepartment of Oral and Maxillofacial Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of ChinaAbstract: Molecular imaging plays a key role in personalized medicine and tumor diagnosis. Quantum dots with near-infrared emission spectra demonstrate excellent tissue penetration and photostability, and have recently emerged as important tools for in vivo tumor imaging. Integrin αvβ3 has been shown to be highly and specifically expressed in endothelial cells of tumor angiogenic vessels in almost all types of tumors, and specifically binds to the peptide containing arginine-glycine-aspartic acid (RGD. In this study, we conjugated RGD with quantum dots with emission wavelength of 800 nm (QD800 to generate QD800-RGD, and used it via intravenous injection as a probe to image tumors in nude mice bearing head and neck squamous cell carcinoma (HNSCC. Twelve hours after the injection, the mice were still alive and were sacrificed to isolate tumors and ten major organs for ex vivo analysis to localize the probe in these tissues. The results showed that QD800-RGD was specifically targeted to integrin αvβ3 in vitro and in vivo, producing clear tumor fluorescence images after the intravenous injection. The tumor-to-background ratio and size of tumor image were highest within 6 hours of the injection and declined significantly at 9 hours after the injection, but there was still a clearly visible tumor image at 12 hours. The greatest amount of QD800-RGD was found in liver and spleen, followed by tumor and lung, and a weak fluorescence signal was seen in tibia. No detectable signal of QD800-RGD was found in brain, heart, kidney, testis, stomach, or intestine. Our study demonstrated that using integrin αvβ3 as target, it is possible to use intravenously injected QD800-RGD to generate high quality images of HNSCC, and the technique offers great potential

  16. Functional characterization of six aspartate (D) recombinant mojastin mutants (r-Moj): A second aspartate amino acid carboxyl to the RGD in r-Moj-D_ peptides is not sufficient to induce apoptosis of SK-Mel-28 cells.

    Science.gov (United States)

    Ramos, Carla J; Gutierrez, Daniel A; Aranda, Ana S; Koshlaychuk, Melissa A; Carrillo, David A; Medrano, Rafael; McBride, Terri D; U, Andrew; Medina, Stephanie M; Lombardo, Melissa C; Lucena, Sara E; Sanchez, Elda E; Soto, Julio G

    2016-08-01

    Disintegrins are small peptides produced in viper venom that act as integrin antagonists. When bound to integrins, disintegrins induce altered cellular behaviors, such as apoptotic induction. Disintegrins with RGDDL or RGDDM motifs induce apoptosis of normal and cancer cells. We hypothesized that a second aspartate (D) carboxyl to the RGD is sufficient to induce apoptosis. Five recombinant mojastin D mutants were produced by site-directed mutagenesis (r-Moj-DA, r-Moj-DG, r-Moj-DL, r-Moj-DN, and r-Moj-DV). Stable αv integrin knockdown and shRNA scrambled control SK-Mel-28 cell lines were produced to test a second hypothesis: r-Moj-D_ peptides bind to αv integrin. Only r-Moj-DL, r-Moj-DM, and r-Moj-DN induced apoptosis of SK-Mel-28 cells (at 29.4%, 25.6%, and 36.2%, respectively). Apoptotic induction was significantly reduced in SK-Mel-28 cells with a stable αv integrin knockdown (to 2%, 17%, and 2%, respectively), but not in SK-Mel-28 cells with a stable scrambled shRNA. All six r-Moj-D_ peptides inhibited cell proliferation; ranging from 49.56% (r-Moj-DN) to 75.6% (r-Moj-DA). Cell proliferation inhibition by r-Moj-D_ peptides was significantly reduced in SK-Mel-28 cells with a stable αv integrin knockdown. All six r-Moj-D_ peptides inhibited SK-Mel-28 cell migration at high levels (69%-100%). As a consequence, rac-1 mRNA expression levels were significantly reduced as early as 1 h after treatment, suggesting that rac-1 is involved in the cell migration activity of SK-Mel-28. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The 4-pyridylmethyl ester as a protecting group for glutamic and aspartic acids: 'flipping' peptide charge states for characterization by positive ion mode ESI-MS.

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    Garapati, Sriramya; Burns, Colin S

    2014-03-01

    Use of the 4-pyridylmethyl ester group for side-chain protection of glutamic acid residues in solid-phase peptide synthesis enables switching of the charge state of a peptide from negative to positive, thus making detection by positive ion mode ESI-MS possible. The pyridylmethyl ester moiety is readily removed from peptides in high yield by hydrogenation. Combining the 4-pyridylmethyl ester protecting group with benzyl ester protection reduces the number of the former needed to produce a net positive charge and allows for purification by RP HPLC. This protecting group is useful in the synthesis of highly acidic peptide sequences, which are often beset by problems with purification by standard RP HPLC and characterization by ESI-MS. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  18. Dataset of cocoa aspartic protease cleavage sites

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    Katharina Janek

    2016-09-01

    Full Text Available The data provide information in support of the research article, “The cleavage specificity of the aspartic protease of cocoa beans involved in the generation of the cocoa-specific aroma precursors” (Janek et al., 2016 [1]. Three different protein substrates were partially digested with the aspartic protease isolated from cocoa beans and commercial pepsin, respectively. The obtained peptide fragments were analyzed by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF-MS/MS and identified using the MASCOT server. The N- and C-terminal ends of the peptide fragments were used to identify the corresponding in-vitro cleavage sites by comparison with the amino acid sequences of the substrate proteins. The same procedure was applied to identify the cleavage sites used by the cocoa aspartic protease during cocoa fermentation starting from the published amino acid sequences of oligopeptides isolated from fermented cocoa beans.

  19. Distinguishing d - and l -aspartic and isoaspartic acids in amyloid β peptides with ultrahigh resolution ion mobility spectrometry

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    Zheng, Xueyun; Deng, Liulin; Baker, Erin M.; Ibrahim, Yehia M.; Petyuk, Vladislav A.; Smith, Richard D.

    2017-01-01

    Ion mobility spectrometry (IMS) was utilized to separate Aβ peptide variants containing isomeric asparic and isoaspartic acid residues with either al- ord-form. The abundance of each variant is of great interest in Alzheimer's disease studies and also to evaluate how often these modifications are occurring in other environmental and biological samples.

  20. Evaluation of Ga-DOTA-(D-Asp)n as bone imaging agents: D-aspartic acid peptides as carriers to bone

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    Ogawa, Kazuma; Ishizaki, Atsushi; Takai, Kenichiro; Kitamura, Yoji; Makino, Akira; Kozaka, Takashi; Kiyono, Yasushi; Shiba, Kazuhiro; Odani, Akira

    2017-01-01

    67Ga-DOTA-(L-Asp)11 and 67Ga-DOTA-(L-Asp)14, which have been developed as bone imaging agents, showed a high accumulation in bone and a rapid blood clearance in mice. However, peptides composed of D-amino acids are more stable in vivo than those composed of their L-equivalents. In this study, 67Ga-DOTA-(D-Asp)n (n = 2, 5, 8, 11, or 14) were synthesized using the Fmoc-based solid-phase methodology and evaluated. In hydroxyapatite binding assay, binding of 67Ga-DOTA-(D-Asp)n tended to increase ...

  1. Aspartate aminotransferase (AST) blood test

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    ... gov/ency/article/003472.htm Aspartate aminotransferase (AST) blood test To use the sharing features on this page, please enable JavaScript. The aspartate aminotransferase (AST) blood test measures the level of the enzyme AST in ...

  2. Arabinose and ferulic acid rich pectic polysaccharides extracted from sugar beet pulp.

    NARCIS (Netherlands)

    Oosterveld, A.; Beldman, G.; Schols, H.A.; Voragen, A.G.J.

    1996-01-01

    Arabinose and ferulic acid rich polysaccharides were extracted from sugar beet pulp using two extraction methods: a sequential extraction with H2O (2 times), NaOH/EDTA (2 times), and 4 M NaOH (2 times; method A) and a sequential extraction in which the NaOH/EDTA extraction was replaced by an

  3. Insulin aspart pharmacokinetics

    DEFF Research Database (Denmark)

    Rasmussen, Christian Hove; Roge, Rikke Meldgaard; Ma, Zhulin

    2014-01-01

    Background: Insulin aspart (IAsp) is used by many diabetics as a meal-time insulin to control postprandial glucose levels. As is the case with many other insulin types, the pharmacokinetics (PK), and consequently the pharmacodynamics (PD), is associated with clinical variability, both between...... to investigate and quantify the properties of the subcutaneous depot. Data from Brange et al. (1990) are used to determine the effects of insulin chemistry in subcutis on the absorption rate. Intravenous (i.v.) bolus and infusion PK data for human insulin are used to understand and quantify the systemic...... distribution and elimination (Porksen et al., 1997; Sjostrand et al., 2002). PK and PD profiles for type 1 diabetics from Chen et al. (2005) are analyzed to demonstrate the effects of IAsp antibodies in terms of bound and unbound insulin. PK profiles from Thorisdottir et al. (2009) and Ma et al. (2012b...

  4. TRH-like peptides.

    Science.gov (United States)

    Bílek, R; Bičíková, M; Šafařík, L

    2011-01-01

    TRH-like peptides are characterized by substitution of basic amino acid histidine (related to authentic TRH) with neutral or acidic amino acid, like glutamic acid, phenylalanine, glutamine, tyrosine, leucin, valin, aspartic acid and asparagine. The presence of extrahypothalamic TRH-like peptides was reported in peripheral tissues including gastrointestinal tract, placenta, neural tissues, male reproductive system and certain endocrine tissues. Work deals with the biological function of TRH-like peptides in different parts of organisms where various mechanisms may serve for realisation of biological function of TRH-like peptides as negative feedback to the pituitary exerted by the TRH-like peptides, the role of pEEPam such as fertilization-promoting peptide, the mechanism influencing the proliferative ability of prostatic tissues, the neuroprotective and antidepressant function of TRH-like peptides in brain and the regulation of thyroid status by TRH-like peptides.

  5. Insulin aspart in diabetic pregnancy

    DEFF Research Database (Denmark)

    Mathiesen, Elisabeth R

    2008-01-01

    in insulin requirements during pregnancy necessitate short-acting insulins for postprandial control of hyperglycemia. The fast-acting insulin analogue insulin aspart has been tested in a large, randomized trial of pregnant women with Type 1 diabetes and offers benefits in control of postprandial......Pregnancy in women with diabetes is associated with an increased risk of obstetric complications and perinatal mortality. Maintenance of near-normal glycemia during pregnancy can bring the prevalence of fetal, neonatal and maternal complications closer to that of the nondiabetic population. Changes...... and no increase in insulin antibodies was found. Thus, the use of insulin aspart in pregnancy is regarded safe....

  6. 21 CFR 582.5017 - Aspartic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aspartic acid. 582.5017 Section 582.5017 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5017 Aspartic acid. (a) Product. Aspartic acid (L- and DL-forms). (b) Conditions of use...

  7. Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation

    NARCIS (Netherlands)

    Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouter L J; Frijlink, Henderik W; Mulder, Frans A A

    2013-01-01

    Oxytocin is a peptide drug used to induce labor and prevent bleeding after childbirth. Due to its instability, transport and storage of oxytocin formulations under tropical conditions is problematic. In a previous study, we have found that the stability of oxytocin in aspartate buffered formulation

  8. Cloning and characterization of an endo-b-1,3(4) glucanase and an aspartic protease from Phaffia rhodozyma CBS 6938

    DEFF Research Database (Denmark)

    Villadsen, Ingrid; Bang, M_L; Sandal, T.

    1999-01-01

    We describe the identification and expression cloning of two novel enzymes, a P-glucanase and an aspartic protease, secreted from the basidiomycetous yeast Phaffia rhodozyma. A cDNA library from P. rhodozyma CBS 6938 was constructed, and full-length cDNA encoding an endo-1,3(4)-beta-glucanase (bg1......) and an aspartic protease (pr1) were cloned by expression cloning in Saccharomyces cerevisiae W3124. The bgl cDNA encodes a 424-residue precursor protein with a putative signal peptide. The prl cDNA encodes a 405-residue prepropolypeptide with an 81-residue leader peptide. The aspartic protease was purified...

  9. Lipoprotein profiles and serum peroxide levels of aged women consuming palmolein or oleic acid-rich sunflower oil diets.

    Science.gov (United States)

    Cuesta, C; Ródenas, S; Merinero, M C; Rodríguez-Gil, S; Sánchez-Muniz, F J

    1998-09-01

    To investigate the hypercholesterolemic effects of a dietary exchange between 16:0 and 18:1 while 18:2 was at relatively lower level (approximately 4%) in aged women with initially high total serum cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) values and with high intakes of dietary cholesterol. Subjects were assigned to two consecutive 28 d periods. In the first period all subjects followed an oleic acid-rich diet in the form of oleic acid-rich sunflower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. Nutrient intakes, serum lipids, lipoproteins, antioxidant vitamins, peroxides and LDL-peroxides were measured at two dietary periods. Instituto de Nutrición y Bromatología (CSIC), Departamento de Nutrición y Bromatología I (Nutrición) and Sección Departamental de Quimica Analítica, Universidad Complutense, Madrid, Spain. The palmolein period led to an increase in TC (P or = 6.21 mmol/L or with TC 6.21 mmol/L than in women with TC < 6.21 mmol/L, but palmolein decreased serum and LDL-peroxide in hypercholesterolemics more than in the normocholesterolemics, resulting in serum and LDL-peroxide levels which theoretically are more adequate. Though palmolein increased LDL-C concentrations, it better protected LDL particles, mainly in women with high TC, against peroxidation than did oleic acid-rich sunflower oil.

  10. Bioprospecting the Curculigoside-Cinnamic Acid-Rich Fraction from Molineria latifolia Rhizome as a Potential Antioxidant Therapeutic Agent.

    Science.gov (United States)

    Ooi, Der Jiun; Chan, Kim Wei; Sarega, Nadarajan; Alitheen, Noorjahan Banu; Ithnin, Hairuszah; Ismail, Maznah

    2016-06-17

    Increasing evidence from both experimental and clinical studies depicts the involvement of oxidative stress in the pathogenesis of various diseases. Specifically, disruption of homeostatic redox balance in accumulated body fat mass leads to obesity-associated metabolic syndrome. Strategies for the restoration of redox balance, potentially by exploring potent plant bioactives, have thus become the focus of therapeutic intervention. The present study aimed to bioprospect the potential use of the curculigoside-cinnamic acid-rich fraction from Molineria latifolia rhizome as an antioxidant therapeutic agent. The ethyl acetate fraction (EAF) isolated from M. latifolia rhizome methanolic extract (RME) contained the highest amount of phenolic compounds, particularly curculigoside and cinnamic acid. EAF demonstrated glycation inhibitory activities in both glucose- and fructose-mediated glycation models. In addition, in vitro chemical-based and cellular-based antioxidant assays showed that EAF exhibited high antioxidant activities and a protective effect against oxidative damage in 3T3-L1 preadipocytes. Although the efficacies of individual phenolics differed depending on the structure and concentration, a correlational study revealed strong correlations between total phenolic contents and antioxidant capacities. The results concluded that enriched phenolic contents in EAF (curculigoside-cinnamic acid-rich fraction) contributed to the overall better reactivity. Our data suggest that this bioactive-rich fraction warrants therapeutic potential against oxidative stress-related disorders.

  11. Bioprospecting the Curculigoside-Cinnamic Acid-Rich Fraction from Molineria latifolia Rhizome as a Potential Antioxidant Therapeutic Agent

    Directory of Open Access Journals (Sweden)

    Der Jiun Ooi

    2016-06-01

    Full Text Available Increasing evidence from both experimental and clinical studies depicts the involvement of oxidative stress in the pathogenesis of various diseases. Specifically, disruption of homeostatic redox balance in accumulated body fat mass leads to obesity-associated metabolic syndrome. Strategies for the restoration of redox balance, potentially by exploring potent plant bioactives, have thus become the focus of therapeutic intervention. The present study aimed to bioprospect the potential use of the curculigoside-cinnamic acid-rich fraction from Molineria latifolia rhizome as an antioxidant therapeutic agent. The ethyl acetate fraction (EAF isolated from M. latifolia rhizome methanolic extract (RME contained the highest amount of phenolic compounds, particularly curculigoside and cinnamic acid. EAF demonstrated glycation inhibitory activities in both glucose- and fructose-mediated glycation models. In addition, in vitro chemical-based and cellular-based antioxidant assays showed that EAF exhibited high antioxidant activities and a protective effect against oxidative damage in 3T3-L1 preadipocytes. Although the efficacies of individual phenolics differed depending on the structure and concentration, a correlational study revealed strong correlations between total phenolic contents and antioxidant capacities. The results concluded that enriched phenolic contents in EAF (curculigoside-cinnamic acid-rich fraction contributed to the overall better reactivity. Our data suggest that this bioactive-rich fraction warrants therapeutic potential against oxidative stress-related disorders.

  12. Identification of a vesicular aspartate transporter

    OpenAIRE

    Miyaji, Takaaki; Echigo, Noriko; Hiasa, Miki; Senoh, Shigenori; Omote, Hiroshi; Moriyama, Yoshinori

    2008-01-01

    Aspartate is an excitatory amino acid that is costored with glutamate in synaptic vesicles of hippocampal neurons and synaptic-like microvesicles (SLMVs) of pinealocytes and is exocytosed and stimulates neighboring cells by binding to specific cell receptors. Although evidence increasingly supports the occurrence of aspartergic neurotransmission, this process is still debated because the mechanism for the vesicular storage of aspartate is unknown. Here, we show that sialin, a lysosomal H+/sia...

  13. Identification of a vesicular aspartate transporter

    Science.gov (United States)

    Miyaji, Takaaki; Echigo, Noriko; Hiasa, Miki; Senoh, Shigenori; Omote, Hiroshi; Moriyama, Yoshinori

    2008-01-01

    Aspartate is an excitatory amino acid that is costored with glutamate in synaptic vesicles of hippocampal neurons and synaptic-like microvesicles (SLMVs) of pinealocytes and is exocytosed and stimulates neighboring cells by binding to specific cell receptors. Although evidence increasingly supports the occurrence of aspartergic neurotransmission, this process is still debated because the mechanism for the vesicular storage of aspartate is unknown. Here, we show that sialin, a lysosomal H+/sialic acid cotransporter, is present in hippocampal synaptic vesicles and pineal SLMVs. RNA interference of sialin expression decreased exocytosis of aspartate and glutamate in pinealocytes. Proteoliposomes containing purified sialin actively accumulated aspartate and glutamate to a similar extent when inside positive membrane potential is imposed as the driving force. Sialin carrying a mutation found in people suffering from Salla disease (R39C) was completely devoid of aspartate and glutamate transport activity, although it retained appreciable H+/sialic acid cotransport activity. These results strongly suggest that sialin possesses dual physiological functions and acts as a vesicular aspartate/glutamate transporter. It is possible that people with Salla disease lose aspartergic (and also the associated glutamatergic) neurotransmission, and this could provide an explanation for why Salla disease causes severe neurological defects. PMID:18695252

  14. Utilizing acid-rich effluents of fermentative hydrogen production process as substrate for harnessing bioelectricity: An integrative approach

    Energy Technology Data Exchange (ETDEWEB)

    Mohanakrishna, G.; Venkata Mohan, S.; Sarma, P.N. [Bioengineering and Environmental Centre (BEEC), Indian Institute of Chemical Technology (IICT), Hyderabad 500 607 (India)

    2010-04-15

    Lower substrate degradation is one of the limiting factors associated with fermentative hydrogen production process. To overcome this, an attempt was made to integrate microbial fuel cell (MFC) as a secondary energy generating process with the fermentative hydrogen (H{sub 2}) production. The acid-rich effluents generated from the acidogenic sequential batch biofilm reactor (AcSBBR) producing H{sub 2} by fermenting vegetable waste was subsequently used as substrate for bioelectricity generation in single chambered MFC (air cathode; non-catalyzed electrodes). AcSBBR was operated at 70.4 kg COD/m{sup 3}-day and the outlet was fed to the MFC at three variable organic loading rates. The final outlet from AcSBBR was composed of fermentative soluble acid intermediates along with residual carbon source. Experimental data illustrated the feasibility of utilizing acid-rich effluents by MFC for both additional energy generation and wastewater treatment. Higher power output (111.76 mW/m{sup 2}) was observed at lower substrate loading condition. MFC also illustrated its function as wastewater treatment unit by removing COD (80%), volatile fatty acids (79%), carbohydrates (78%) and turbidity (65.38%) effectively. Fermented form of vegetable wastewater exhibited higher improvement (94%) in power compared to unfermented wastewater. The performance of MFC was characterized with respect to polarization behavior, cell potentials, cyclic voltammetry and sustainable power. This integration approach enhanced wastewater treatment efficiency (COD removal, 84.6%) along with additional energy generation demonstrating both environmental and economic sustainability of the process. (author)

  15. Secreted fungal aspartic proteases: A review.

    Science.gov (United States)

    Mandujano-González, Virginia; Villa-Tanaca, Lourdes; Anducho-Reyes, Miguel Angel; Mercado-Flores, Yuridia

    2016-01-01

    The aspartic proteases, also called aspartyl and aspartate proteases or acid proteases (E.C.3.4.23), belong to the endopeptidase family and are characterized by the conserved sequence Asp-Gly-Thr at the active site. These enzymes are found in a wide variety of microorganisms in which they perform important functions related to nutrition and pathogenesis. In addition, their high activity and stability at acid pH make them attractive for industrial application in the food industry; specifically, they are used as milk-coagulating agents in cheese production or serve to improve the taste of some foods. This review presents an analysis of the characteristics and properties of secreted microbial aspartic proteases and their potential for commercial application. Copyright © 2016 Asociación Española de Micología. Published by Elsevier Espana. All rights reserved.

  16. Intracellular traffic of the lysine and glutamic acid rich protein KERP1 reveals features of endomembrane organization in Entamoeba histolytica.

    Science.gov (United States)

    Perdomo, Doranda; Manich, Maria; Syan, Sylvie; Olivo-Marin, Jean-Christophe; Dufour, Alexandre C; Guillén, Nancy

    2016-08-01

    The development of amoebiasis is influenced by the expression of the lysine and glutamic acid rich protein 1 (KERP1), a virulence factor involved in Entamoeba histolytica adherence to human cells. Up to date, it is unknown how the protein transits the parasite cytoplasm towards the plasma membrane, specially because this organism lacks a well-defined endoplasmic reticulum (ER) and Golgi apparatus. In this work we demonstrate that KERP1 is present at the cell surface and in intracellular vesicles which traffic in a pathway that is independent of the ER-Golgi anterograde transport. The intracellular displacement of vesicles enriched in KERP1 relies on the actin-rich cytoskeleton activities. KERP1 is also present in externalized vesicles deposited on the surface of human cells. We further report the interactome of KERP1 with its association to endomembrane components and lipids. The model for KERP1 traffic here proposed hints for the first time elements of the endocytic and exocytic paths of E. histolytica. © 2016 John Wiley & Sons Ltd.

  17. Conversion of cheese whey into a fucose- and glucuronic acid-rich extracellular polysaccharide by Enterobacter A47.

    Science.gov (United States)

    Antunes, Sílvia; Freitas, Filomena; Alves, Vítor D; Grandfils, Christian; Reis, Maria A M

    2015-09-20

    Cheese whey was used as the sole substrate for the production of extracellular polysaccharides (EPS) by Enterobacter A47. An EPS concentration of 6.40 g L(-1) was reached within 3.2 days of cultivation, corresponding to a volumetric productivity of 2.00 g L(-1) d(-1). The produced EPS was mainly composed of glucuronic acid (29 mol%) and fucose (29 mol%), with lower contents of glucose and galactose (21 mol% each) and a total acyl groups content of 32 wt.%. The polymer had an average molecular weight of 1.8×10(6) Da, with a polydispersity index of 1.2, and an intrinsic viscosity of 8.0 dL g(-1). EPS aqueous solutions (1.0 wt.% in 0.01 M NaCl, at pH 8.0) presented a shear thinning behavior with a viscosity of the first Newtonian plateau approaching 0.1 Pas. This novel glucuronic acid-rich polymer possesses interesting rheological properties, which, together with its high content of glucuronic acid and fucose, two bioactive sugar monomers, confers it a great potential for use in high-value applications, such as cosmetics and pharmaceuticals. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Fatty acid rich effluent from acidogenic biohydrogen reactor as substrate for lipid accumulation in heterotrophic microalgae with simultaneous treatment.

    Science.gov (United States)

    Venkata Mohan, S; Prathima Devi, M

    2012-11-01

    Acid-rich effluent generated from acidogenic biohydrogen production process was evaluated as substrate for lipid synthesis by integrating with heterotrophic cultivation of mixed microalgae. Experiments were performed both with synthetic volatile fatty acids (SVFA) and fermented fatty acids (FFA) from biohydrogen producing reactor. Fatty acid based platform evidenced significant influence on algal growth as well as lipid accumulation by the formation of triglycerides through fatty acid synthesis. Comparatively FFA documented higher biomass and lipid productivity (1.42mg/ml (wet weight); 26.4%) than SVFAs ((HAc+HBu+HPr), 0.60mg/ml; 23.1%). Lipid profiles varied with substrates and depicted 18 types of saturated and unsaturated fatty acids with wide fuel and food characteristics. The observed higher concentrations of Chl b over Chl a supports the biosynthesis of triacylglycerides. Microalgae diversity visualized the presence of lipid accumulating species viz., Scenedesmus sp. and Chlorella sp. Integration of microalgae cultivation with biohydrogen production showed lipid productivity for biodiesel production along with additional treatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Applied potentials regulate recovery of residual hydrogen from acid-rich effluents: Influence of biocathodic buffer capacity over process performance.

    Science.gov (United States)

    Nikhil, G N; Venkata Mohan, S; Swamy, Y V

    2015-01-01

    An absolute biological microbial electrolysis cell (MEC) was operated for a prolonged period under different applied potentials (Eapp, -0.2V to -1.0V) and hydrogen (H2) production was observed using acid-rich effluent. Among these potentials, an optimal voltage of -0.6 V influenced the biocathode by which maximum H2 production of 120 ± 9 ml was noticed. This finding was corroborated with dehydrogenase activity (1.8 ± 0.1 μg/ml) which is the key enzyme for H2 production. The in situ biocathode regulated buffer overpotentials which was remarkably observed by the change in peak heights of dissociation value (pKa) from the titration curve. Substrate degradation analysis gave an estimate of coulombic efficiency of about 72 ± 5% when operated at optimal voltage. Evidently, the electron transfer from solid carbon electrode to biocathode was analyzed by cyclic voltammetry and its derivatives showed the involvement of redox mediators. Despite, the MEC endures certain activation overpotentials which were estimated from the Tafel slope analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Rosmarinic Acid-Rich Extracts of Summer Savory (Satureja hortensis L. Protect Jurkat T Cells against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Irakli Chkhikvishvili

    2013-01-01

    Full Text Available Summer savory (Satureja hortensis L., Lamiaceae is used in several regions of the world as a spice and folk medicine. Anti-inflammatory and cytoprotective effects of S. hortensis and of its rosmarinic acid-rich phenolic fraction have been demonstrated in animal trials. However, previous studies of rosmarinic acid in cell models have yielded controversial results. In this study, we investigated the effects of summer savory extracts on H2O2-challenged human lymphoblastoid Jurkat T cells. LC-MS analysis confirmed the presence of rosmarinic acid and flavonoids such as hesperidin and naringin in the phenolic fraction. Adding 25 or 50 µM of H2O2 to the cell culture caused oxidative stress, manifested as generation of superoxide and peroxyl radicals, reduced cell viability, G0/G1 arrest, and enhanced apoptosis. This stress was significantly alleviated by the ethanolic and aqueous extracts of S. hortensis and by the partially purified rosmarinic acid fraction. The application of an aqueous S. hortensis extract doubled the activity of catalase and superoxide dismutase in the cells. The production of IL-2 and IL-10 interleukins was stimulated by H2O2 and was further enhanced by the addition of the S. hortensis extract or rosmarinic acid fraction. The H2O2-challenged Jurkat cells may serve as a model for investigating cellular mechanisms of cytoprotective phytonutrient effects.

  1. An iso-α-acid-rich extract from hops (Humulus lupulus) attenuates acute alcohol-induced liver steatosis in mice.

    Science.gov (United States)

    Hege, Marianne; Jung, Finn; Sellmann, Cathrin; Jin, Chengjun; Ziegenhardt, Doreen; Hellerbrand, Claus; Bergheim, Ina

    2018-01-01

    Results of in vitro and in vivo studies suggest that consumption of beer is less harmful for the liver than consumption of spirits. It also has been suggested that secondary plant compounds derived from hops such as xanthohumol or iso-α-acids may have beneficial effects on the development of liver diseases of various etiologies. The aim of this study was to determine whether iso-α-acids consumed in doses achieved by "normal" beer consumption have beneficial effects on health. Female C57 Bl/6 J mice, pretreated for 4 d with an iso-α-acid-rich extract (∼30% iso-α-acids from hops, 0.75 mg/kg body weight), were fed one bolus of ethanol (6 g/kg body weight intragastric) or an iso-caloric maltodextrin solution. Markers of liver damage, toll-like receptor-4 signaling, and lipid peroxidation were determined. Furthermore, the effect of isohumulone on the lipopolysaccharide-dependent activation of J774 A.1 macrophages, used as a model of Kupffer cells, was determined. In the liver, acute ethanol administration led to a significant accumulation of fat (∼10-fold), which was accompanied by significantly higher inducible nitric oxide synthase protein level, elevated nitric oxide production, and increased plasminogen activator inhibitor 1 protein concentration when compared to controls. In mice pretreated with iso-α-acids, these effects of alcohol were markedly attenuated. Pretreatment of J774 A.1 macrophages with isohumulone significantly attenuated lipopolysaccharide-induced mRNA expression of inducible nitric oxide synthase and interleukin-6 as well as the release of nitric oxide. Taken together, iso-α-acids markedly attenuated the development of acute alcohol-induced damage in mice. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Improved tumor targeting of radiolabeled RGD peptides using rapid dose fractionation.

    NARCIS (Netherlands)

    Janssen, M.; Frielink, C.; Dijkgraaf, I.; Oyen, W.J.G.; Edwards, D.S.; Liu, S.; Rajopadhye, M.; Massuger, L.F.A.G.; Corstens, F.H.M.; Boerman, O.C.

    2004-01-01

    Arginine-glycine-aspartic acid (RGD) peptides preferentially bind to alphavbeta3 integrin, an integrin expressed on newly formed endothelial cells and on various tumor cells. When labeled with beta-emitting radionuclides, these peptides can be used for peptide-receptor radionuclide therapy of

  3. Sperm and Egg Jelly Coat from Sea Urchin Lytechinus variegatus Collected in Rio de Janeiro Contain Distinct Sialic Acid-Rich Polysaccharides

    Directory of Open Access Journals (Sweden)

    Gabrielle M. Valle

    2015-08-01

    Full Text Available This work found the occurrence of a distinct sialic acid-rich polysaccharide in the sperm surface of the sea urchin Lytechinus variegatus, which differed significantly from a similar molecule found in the egg jelly. The sperm polysaccharide extracted by protease digestion was purified using anion exchange chromatography and characterized using agarose gel electrophoresis, gas chromatography/mass spectrometry and NMR spectroscopy. This polysaccharide was highly sulfated and composed almost exclusively of N-acetylneuraminic acid. In contrast, the sialic acid-rich polysaccharide from the egg jelly was composed of N-glycolylneuraminic acid and contains several other hexoses in its structure. This new molecule could help to characterize in further detail the mechanism of fertilization in the sea urchin model system. Sulfated polysaccharides from the jelly coat of sea urchins showed species-specificity in inducing the sperm acrosome reaction, providing an example of a signal transduction event regulated by the sulfated polysaccharide. The new sialic acid-rich polysaccharide found in the sperm head could represent a new molecule involved in the biology of the sea urchin fertilization.

  4. Conformational behavior of ionic self-complementary peptides.

    OpenAIRE

    Altman, M; Lee, P; Rich, A.; Zhang, S.

    2000-01-01

    Several de novo designed ionic peptides that are able to undergo conformational change under the influence of temperature and pH were studied. These peptides have two distinct surfaces with regular repeats of alternating hydrophilic and hydrophobic side chains. This permits extensive ionic and hydrophobic interactions resulting in the formation of stable beta-sheet assemblies. The other defining characteristic of this type of peptide is a cluster of negatively charged aspartic or glutamic aci...

  5. Interaction of rose bengal with mung bean aspartate transcarbamylase

    Indian Academy of Sciences (India)

    tribpo

    Abstract. The fluorescein dye, rose bengal in the dark: (i) inhibited the activity of mung bean aspartate transcarbamylase (EC 2.1.3.2) in a non-competitive manner, when aspartate was the varied substrate; (ii) induced a lag in the time course of reaction and this hysteresis was abolished upon preincubation with carbamyl ...

  6. Radiopharmaceutical development of radiolabelled peptides

    Energy Technology Data Exchange (ETDEWEB)

    Fani, Melpomeni; Maecke, Helmut R. [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany)

    2012-02-15

    Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as {sup 99m}Tc, M{sup 3+} radiometals ({sup 111}In, {sup 86/90}Y, {sup 177}Lu, {sup 67/68}Ga), {sup 64/67}Cu, {sup 18}F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin

  7. STABILITY OF BINARY COMPLEXES OF L-ASPARTIC ACID IN ...

    African Journals Online (AJOL)

    Preferred Customer

    KEY WORDS: Binary complexes, Stability constants, Aspartic acid, Speciation, Dioxan ... Potentiometric study of Fe(II) and Zn(II) was carried out by Ritsma [19], Maker et al. [20],. Gergely and .... The effect of variations in asymmetry potential,.

  8. Extraction of unsaturated fatty acid-rich oil from common carp (Cyprinus carpio) roe and production of defatted roe hydrolysates with functional, antioxidant, and antibacterial properties

    DEFF Research Database (Denmark)

    Ghelichi, Sakhi; Shabanpour, Bahareh; Pourashouri, Parastoo

    2017-01-01

    content of essential amino acids. CDRHs displayed higher solubility than untreated defatted roe, which increased with DH. Better emulsifying and foaming properties were observed at lower DH and non-isoelectric points. Furthermore, water and oil binding capacity decreased with DH. CDRHs exhibited...... of hydrolysis (DH). Gas chromatography (GC) of fatty acid methyl esters (FAMEs) revealed that common carp roe oil contained high level of unsaturated fatty acids. The results of high-performance liquid chromatography-mass spectrometry (HPLC-MS) indicated that enzymatic hydrolysis of defatted roe yielded higher...... antioxidant activity both in vitro and in 5% roe oil-in-water emulsions and inhibited the growth of certain bacterial strains. Common carp roe could be a promising source of unsaturated fatty acids and functional bioactive agents. Unsaturated fatty acid-rich oil extracted from common carp roe can be delivered...

  9. Red cell aspartate aminotransferase saturation with oral pyridoxine intake

    OpenAIRE

    Oshiro, Marilena; Nonoyama, Kimiyo; Oliveira, Raimundo Antônio Gomes; Barretto, Orlando Cesar de Oliveira

    2005-01-01

    CONTEXT AND OBJECTIVE: The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronie’s syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell aspartate aminotransferase. DESIGN AND SETTING: Controlled trial, in Hematology Division of Instituto...

  10. Red cell aspartate aminotransferase saturation with oral pyridoxine intake

    Directory of Open Access Journals (Sweden)

    Marilena Oshiro

    Full Text Available CONTEXT AND OBJECTIVE: The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronie’s syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell aspartate aminotransferase. DESIGN AND SETTING: Controlled trial, in Hematology Division of Instituto Adolfo Lutz. METHODS: Red cell aspartate aminotransferase activity was assayed (before and after in normal volunteers who were given oral pyridoxine for 15-18 days (30 mg, 100 mg and 200 mg daily. In vitro study of blood from seven normal volunteers was also performed, with before and after assaying of aspartate aminotransferase activity. RESULTS: The in vivo study showed increasing aspartate aminotransferase saturation with increasing pyridoxine doses. 83% saturation was reached with 30 mg daily, 88% with 100 mg, and 93% with 200 mg after 20 days of oral supplementation. The in vitro study did not reach 100% saturation. CONCLUSIONS: Neither in vivo nor in vitro study demonstrated thorough aspartate aminotransferase saturation with its coenzyme pyridoxal phosphate in red cells, from increasing pyridoxine supplementation. However, the 200-mg dose could be employed safely in vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronie’s syndrome treatment. Although maximum saturation in circulating red cells is not achieved, erythroblasts and other nucleated and cytoplasmic organelles containing cells certainly will reach thorough saturation, which possibly explains the results obtained in these diseases.

  11. PEPTIDE SOLUBILITY, STRUCTURE AND CHARGE POSITION EFFECT ON ADSORPTION BY ALUMINIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Mary Trujillo

    2008-04-01

    Full Text Available Solubility, structure and position of charges in a peptide antigen sequence can be mentioned as being amongst the basic features of adsorption. In order to study their effect on adsorption, seven analogue series were synthesized from a MSP-1 peptide sequence by systematically replacing each one of the positions in the peptide sequence by aspartic acid, glutamic acid, serine, alanine, asparagine, glutamine or lysine. Such modifications in analogue peptide sequences showed a non-regular tendency regarding solubility and adsorption data. Aspartic acid and Glutamic acid analogue series showed great improvements in adsorption, especially in peptides where Lysine in position 6 and Arginine in position 13 were replaced. Solubility of position 5 analogue was greater than the position 6 analogue in Aspartic acid series; however, the position 6 analogue showed best adsorption results whilst the Aspartic acid in position 5 analogue showed no adsorption in the same conditions. Nuclear Magnetic Resonance structural analysis revealed differences in the -helical structureextension between these analogues. The Aspartic acid in position 6, located in the polar side of the helix, may allow this analogueto fit better onto the adsorption regions suggesting that the local electrostatic charge is responsible for this behavior.

  12. [Aspartate aminotransferase--key enzyme in the human systemic metabolism].

    Science.gov (United States)

    Otto-Ślusarczyk, Dagmara; Graboń, Wojciech; Mielczarek-Puta, Magdalena

    2016-03-16

    Aspartate aminotransferase is an organ-nonspecific enzyme located in many tissues of the human body where it catalyzes reversible reaction of transamination. There are two aspartate aminotransferase isoforms--cytoplasmic (AST1) and mitochondrial (AST2), that usually occur together and interact with each other metabolically. Both isoforms are homodimers containing highly conservative regions responsible for catalytic properties of enzyme. The common feature of all aspartate aminotransfeses is Lys - 259 residue covalent binding with prosthetic group - pyridoxal phosphate. The differences in the primary structure of AST isoforms determine their physico-chemical, kinetic and immunological properties. Because of the low concentration of L-aspartate (L-Asp) in the blood, AST is the only enzyme, which supply of this amino acid as a substrate for many metabolic processes, such as urea cycle or purine and pyrimidine nucleotides in the liver, synthesis of L-arginine in the kidney and purine nucleotide cycle in the brain and the skeletal muscle. AST is also involved in D-aspartate production that regulates the metabolic activity at the auto-, para- and endocrine level. Aspartate aminotransferase is a part of the malate-aspartate shuttle in the myocardium, is involved in gluconeogenesis in the liver and kidney, glyceroneogenesis in the adipose tissue, and synthesis of neurotransmitters and neuro-glial pathway in the brain. Recently, the significant role of AST in glutaminolysis - normal metabolic pathway in tumor cells, was demonstrated. The article is devoted the role of AST, known primarily as a diagnostic liver enzyme, in metabolism of various human tissues and organs.

  13. Aspartate aminotransferase – key enzyme in the human systemic metabolism

    Directory of Open Access Journals (Sweden)

    Dagmara Otto-Ślusarczyk

    2016-03-01

    Full Text Available Aspartate aminotransferase is an organ - nonspecific enzyme located in many tissues of the human body where it catalyzes reversible reaction of transamination. There are two aspartate aminotransferase isoforms - cytoplasmic (AST1 and mitochondrial (AST2, that usually occur together and interact with each other metabolically. Both isoforms are homodimers containing highly conservative regions responsible for catalytic properties of enzyme. The common feature of all aspartate aminotransfeses is Lys – 259 residue covalent binding with prosthetic group - pyridoxal phosphate. The differences in the primary structure of AST isoforms determine their physico-chemical, kinetic and immunological properties. Because of the low concentration of L-aspartate (L-Asp in the blood, AST is the only enzyme, which supply of this amino acid as a substrate for many metabolic processes, such as urea cycle or purine and pyrimidine nucleotides in the liver, synthesis of L-arginine in the kidney and purine nucleotide cycle in the brain and the skeletal muscle. AST is also involved in D-aspartate production that regulates the metabolic activity at the auto-, para- and endocrine level. Aspartate aminotransferase is a part of the malate-aspartate shuttle in the myocardium, is involved in gluconeogenesis in the liver and kidney, glyceroneogenesis in the adipose tissue, and synthesis of neurotransmitters and neuro-glial pathway in the brain. Recently, the significant role of AST in glutaminolysis - normal metabolic pathway in tumor cells, was demonstrated. The article is devoted the role of AST, known primarily as a diagnostic liver enzyme, in metabolism of various human tissues and organs.

  14. Expression, activation and processing of a novel plant milk-clotting aspartic protease in Pichia pastoris.

    Science.gov (United States)

    Feijoo-Siota, Lucía; Rama, José Luis R; Sánchez-Pérez, Angeles; Villa, Tomás G

    2018-02-20

    Galium verum, also known as Lady's Bedstraw or Cheese Rennet, is an herbaceous perennial plant traditionally used in cheese-making. We used RACE PCR to isolate novel enzymes from Galium verum with the ability to clot milk. This approach generated two cDNA sequences (named preprogaline A and B) encoding proteins displaying the typical plant aspartic protease primary structure. Preprogaline B was expressed in the yeast Pichia pastoris, after deleting and replacing its original signal peptide with the yeast α-factor signal peptide from Saccharomyces cerevisiae. The secreted recombinant protein was obtained by growing P. pastoris in YPD medium and had the ability to clot milk. The mature form of progaline B is a heterodimeric glycosylated enzyme, with a molecular weight of approximately 48 kDa, that contains a heavy (30.7 kDa) and a light (13.5 kDa) polypeptide chains linked by disulfide bonds. Western blot analysis revealed that progaline B is activated by the acidification of the yeast culture medium and that enzymatic activation requires two steps. First the precursor protein is cleaved into two polypeptide chains by partial removal of the plant-specific insert (PSI) present in plant aspartic proteases; this is later followed by propeptide removal. By altering the pH of the P. pastoris culture medium, we were able to obtain either active or inactive forms of the enzyme. Recombinant progaline B displayed a κ-casein hydrolysis pattern analogous to those produced by the animal and microbial coagulants currently used in the dairy industry, but it exhibited a different digestion profile on α- and β-caseins. The plant protease progaline B displays milk-clotting activities suitable for the production of novel dairy products. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Bioactive Peptides

    Directory of Open Access Journals (Sweden)

    Eric Banan-Mwine Daliri

    2017-04-01

    Full Text Available The increased consumer awareness of the health promoting effects of functional foods and nutraceuticals is the driving force of the functional food and nutraceutical market. Bioactive peptides are known for their high tissue affinity, specificity and efficiency in promoting health. For this reason, the search for food-derived bioactive peptides has increased exponentially. Over the years, many potential bioactive peptides from food have been documented; yet, obstacles such as the need to establish optimal conditions for industrial scale production and the absence of well-designed clinical trials to provide robust evidence for proving health claims continue to exist. Other important factors such as the possibility of allergenicity, cytotoxicity and the stability of the peptides during gastrointestinal digestion would need to be addressed. This review discusses our current knowledge on the health effects of food-derived bioactive peptides, their processing methods and challenges in their development.

  16. Bioactive Peptides.

    Science.gov (United States)

    Daliri, Eric Banan-Mwine; Oh, Deog H; Lee, Byong H

    2017-04-26

    The increased consumer awareness of the health promoting effects of functional foods and nutraceuticals is the driving force of the functional food and nutraceutical market. Bioactive peptides are known for their high tissue affinity, specificity and efficiency in promoting health. For this reason, the search for food-derived bioactive peptides has increased exponentially. Over the years, many potential bioactive peptides from food have been documented; yet, obstacles such as the need to establish optimal conditions for industrial scale production and the absence of well-designed clinical trials to provide robust evidence for proving health claims continue to exist. Other important factors such as the possibility of allergenicity, cytotoxicity and the stability of the peptides during gastrointestinal digestion would need to be addressed. This review discusses our current knowledge on the health effects of food-derived bioactive peptides, their processing methods and challenges in their development.

  17. A glutamate/aspartate switch controls product specificity in a protein arginine methyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Debler, Erik W.; Jain, Kanishk; Warmack, Rebeccah A.; Feng, You; Clarke, Steven G.; Blobel, Günter; Stavropoulos, Pete

    2016-02-08

    Trypanosoma brucei PRMT7 (TbPRMT7) is a protein arginine methyltransferase (PRMT) that strictly monomethylates various substrates, thus classifying it as a type III PRMT. However, the molecular basis of its unique product specificity has remained elusive. Here, we present the structure of TbPRMT7 in complex with its cofactor product S-adenosyl-L-homocysteine (AdoHcy) at 2.8 Å resolution and identify a glutamate residue critical for its monomethylation behavior. TbPRMT7 comprises the conserved methyltransferase and β-barrel domains, an N-terminal extension, and a dimerization arm. The active site at the interface of the N-terminal extension, methyltransferase, and β-barrel domains is stabilized by the dimerization arm of the neighboring protomer, providing a structural basis for dimerization as a prerequisite for catalytic activity. Mutagenesis of active-site residues highlights the importance of Glu181, the second of the two invariant glutamate residues of the double E loop that coordinate the target arginine in substrate peptides/proteins and that increase its nucleophilicity. Strikingly, mutation of Glu181 to aspartate converts TbPRMT7 into a type I PRMT, producing asymmetric dimethylarginine (ADMA). Isothermal titration calorimetry (ITC) using a histone H4 peptide showed that the Glu181Asp mutant has markedly increased affinity for monomethylated peptide with respect to the WT, suggesting that the enlarged active site can favorably accommodate monomethylated peptide and provide sufficient space for ADMA formation. In conclusion, these findings yield valuable insights into the product specificity and the catalytic mechanism of protein arginine methyltransferases and have important implications for the rational (re)design of PRMTs.

  18. Enhanced splicing correction effect by an oligo-aspartic acid-PNA conjugate and cationic carrier complexes.

    Science.gov (United States)

    Bae, Yun Mi; Kim, Myung Hee; Yu, Gwang Sig; Um, Bong Ho; Park, Hee Kyung; Lee, Hyun-il; Lee, Kang Taek; Suh, Yung Doug; Choi, Joon Sig

    2014-02-10

    Peptide nucleic acids (PNAs) are synthetic structural analogues of DNA and RNA. They recognize specific cellular nucleic acid sequences and form stable complexes with complementary DNA or RNA. Here, we designed an oligo-aspartic acid-PNA conjugate and showed its enhanced delivery into cells with high gene correction efficiency using conventional cationic carriers, such as polyethylenimine (PEI) and Lipofectamine 2000. The negatively charged oligo-aspartic acid-PNA (Asp(n)-PNA) formed complexes with PEI and Lipofectamine, and the resulting Asp(n)-PNA/PEI and Asp(n)-PNA/Lipofectamine complexes were introduced into cells. We observed significantly enhanced cellular uptake of Asp(n)-PNA by cationic carriers and detected an active splicing correction effect even at nanomolar concentrations. We found that the splicing correction efficiency of the complex depended on the kind of the cationic carriers and on the number of repeating aspartic acid units. By enhancing the cellular uptake efficiency of PNAs, these results may provide a novel platform technology of PNAs as bioactive substances for their biological and therapeutic applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Effects of linker variation on the in vitro and in vivo characteristics of an 111In-labeled RGD peptide.

    NARCIS (Netherlands)

    Dijkgraaf, I.; Liu, S.; Kruijtzer, J.A.; Soede, A.C.; Oyen, W.J.G.; Liskamp, R.M.; Corstens, F.H.M.; Boerman, O.C.

    2007-01-01

    INTRODUCTION: Due to the selective expression of the alpha(v)beta3 integrin in tumors, radiolabeled arginine-glycine-aspartic acid (RGD) peptides are attractive candidates for tumor targeting. Minor modifications of these peptides could have a major impact on in vivo characteristics. In this study,

  20. Peptide YY.

    Science.gov (United States)

    Chandarana, Keval; Batterham, Rachel

    2008-02-01

    This review discusses recent studies examining the effects of peptide YY on energy homeostasis, highlights the emerging hedonic effects of peptide YY and evaluates the therapeutic potential of the peptide YY system. A role for exogenous PYY3-36 as an anorectic agent in obese humans and rodents has been established and weight loss effects demonstrated in obese rodents. New lines of evidence support a role for endogenous peptide YY in regulating energy homeostasis. The NPY-Y2 receptor mediates the anorectic actions of PYY3-36 with rodent studies implicating the hypothalamus, vagus and brainstem as key target sites. Functional imaging in humans has confirmed that PYY3-36 activates brainstem and hypothalamic regions. The greatest effects, however, were observed within the orbitofrontal cortex, a brain region involved in reward processing. Further evidence for a hedonic role for PYY3-36 is supported by rodent studies showing that PYY3-36 decreases the motivation to seek high-fat food. Rodent studies using selective Y2 agonists and strategies combining PYY3-36/Y2 agonists with other anorectic agents have revealed increased anorectic and weight-reducing effects. Peptide YY plays a role in the integrative regulation of metabolism. The emerging hedonic effects of peptide YY together with the weight-reducing effects observed in obese rodents suggest that targeting the peptide YY system may offer a therapeutic strategy for obesity.

  1. Fish Scales as Potential Substrate for Production of Alkaline Protease and Amino Acid Rich Aqua Hydrolyzate byBacillus altitudinisGVC11.

    Science.gov (United States)

    Harikrishna, N; Mahalakshmi, S; Kiran Kumar, K; Reddy, Gopal

    2017-09-01

    Fish processing industries generate large quantities of fish scales as processing waste, if not treated leading to environmental pollution. Fish scales are hard to degrade, hence cause difficulty in waste management. In this context present study was made to utilize fish scales as substrate for the production of alkaline protease by Bacillus altitudinis GVC11 and subsequently amino acid rich aqua hydrolyzate. B. altitudinis GVC11 efficiently utilized five types of fish scales as substrates and produced maximum alkaline protease using Labeo rohita (28,150 U/mL) followed by Catla catla (23,320 U/mL) at 48 h and Cyprinus carpio (17,146 U/mL) Mugil cephalus (18,917 U/mL) , Cirrhinus mrigala (12,430 U/mL) at 72 h. The HPLC analysis of protein hydrolyzate obtained after fermentation was enriched in essential amino acids, leucine, isoleucine, phenylalanine, lysine and non-essential amino acids, tyrosine, arginine and cysteine which can be used as animal feed supplement and organic fertilizer.

  2. Extraction of unsaturated fatty acid-rich oil from common carp (Cyprinus carpio) roe and production of defatted roe hydrolysates with functional, antioxidant, and antibacterial properties.

    Science.gov (United States)

    Ghelichi, Sakhi; Shabanpour, Bahareh; Pourashouri, Parastoo; Hajfathalian, Mona; Jacobsen, Charlotte

    2017-08-03

    Common carp roe is a rich protein and oil source, which is usually discarded with no specific use. The aims of this study were to extract oil from the discarded roe and examine functional, antioxidant, and antibacterial properties of defatted roe hydrolysates (CDRHs) at various degrees of hydrolysis (DH). Gas chromatography of fatty acid methyl esters revealed that common carp roe oil contained high levels of unsaturated fatty acids. The results of high-performance liquid chromatography-mass spectrometry indicated that enzymatic hydrolysis of defatted roe yielded higher content of essential amino acids. CDRHs displayed higher solubility than untreated defatted roe, which increased with DH. Better emulsifying and foaming properties were observed at lower DH and non-isoelectric points. Furthermore, water and oil binding capacity decreased with DH. CDRHs exhibited antioxidant activity both in vitro and in 5% roe oil-in-water emulsions and inhibited the growth of certain bacterial strains. Common carp roe could be a promising source of unsaturated fatty acids and functional bioactive agents. Unsaturated fatty acid-rich oil extracted from common carp roe can be delivered into food systems by roe oil-in-water emulsions fortified by functional, antioxidant, and antibacterial hydrolysates from the defatted roe. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  3. Comparison between extra virgin olive oil and oleic acid rich sunflower oil: effects on postprandial lipemia and LDL susceptibility to oxidation.

    Science.gov (United States)

    Nicolaïew, N; Lemort, N; Adorni, L; Berra, B; Montorfano, G; Rapelli, S; Cortesi, N; Jacotot, B

    1998-01-01

    The aim of our study was to determine whether the minor polar components of virgin olive oil could have favorable effects (1) on fasting and postprandial lipid profile and (2) on low-density lipoprotein (LDL) composition and susceptibility to oxidation in vitro. Ten normolipidic subjects were included in a crossover study (two diet periods of 3 weeks) and received either virgin olive oil (OO diet) or oleic acid rich sunflower oil. An oral fat load was performed at the end of each period. The plasma lipid levels were not significantly different after both diets in the fasting and postprandial states. A few minor variations of the LDL composition were observed only in the postprandial lipemia, and they were different after both diets. The LDL oxidation susceptibility was evaluated by the formation of conjugated dienes. With LDL isolated in the fasting state, the diene production decreased (p = 0.0573) only after the OO diet. The dienes determined at time 0 and the maximal dienes obtained during the oxidation reaction decreased (p = 0.0145 and p = 0.0184, respectively) only after the OO fat load. Nevertheless, the diene production decrease was not significant (p = 0.0848). Our results suggest a mild effect of minor components of virgin olive oil related to a decrease of LDL susceptibility to oxidation; further analyses are necessary to give clear conclusions about their role.

  4. Regular consumption of a silicic acid-rich water prevents aluminium-induced alterations of nitrergic neurons in mouse brain: histochemical and immunohistochemical studies.

    Science.gov (United States)

    Foglio, E; Buffoli, B; Exley, C; Rezzani, R; Rodella, L F

    2012-08-01

    Silicon is not generally considered an essential nutrient for mammals and, to date, whether it has a biological role or beneficial effects in humans is not known. The results of a number of studies suggest that dietary silicon supplementation might have a protective effect both for limiting aluminium absorption across the gut and for the removal of systemic aluminium via the urine, hence, preventing potential accumulation of aluminium in the brain. Since our previous studies demonstrated that aluminium exposure reduces the number of nitrergic neurons, the aim of the present study was to compare the distribution and the morphology of NO-containing neurons in brain cortex of mice exposed to aluminium sulphate dissolved in silicic acid-rich or poor drinking water to assess the potential protective role of silicon against aluminium toxicity in the brain. NADPH-d histochemistry and nNOS immunohistochemistry showed that high concentrations of silicon in drinking water were able to minimize the impairment of the function of nitrergic neurons induced by aluminium administration. We found that silicon protected against aluminium-induced damage to the nitrergic system: in particular, we demonstrated that silicon maintains the number of nitrergic neurons and their expression of nitrergic enzymes at physiological levels, even after a 12 and 15 month exposure to aluminium.

  5. Characterization of the aspartate transcarbamoylase from Methanococcus jannaschii.

    Science.gov (United States)

    Hack, E S; Vorobyova, T; Sakash, J B; West, J M; Macol, C P; Hervé, G; Williams, M K; Kantrowitz, E R

    2000-05-26

    The genes from the thermophilic archaeabacterium Methanococcus jannaschii that code for the putative catalytic and regulatory chains of aspartate transcarbamoylase were expressed at high levels in Escherichia coli. Only the M. jannaschii PyrB (Mj-PyrB) gene product exhibited catalytic activity. A purification protocol was devised for the Mj-PyrB and M. jannaschii PyrI (Mj-PyrI) gene products. Molecular weight measurements of the Mj-PyrB and Mj-PyrI gene products revealed that the Mj-PyrB gene product is a trimer and the Mj-PyrI gene product is a dimer. Preliminary characterization of the aspartate transcarbamoylase from M. jannaschii cell-free extract revealed that the enzyme has a similar molecular weight to that of the E. coli holoenzyme. Kinetic analysis of the M. jannaschii aspartate transcarbamoylase from the cell-free extract indicates that the enzyme exhibited limited homotropic cooperativity and little if any regulatory properties. The purified Mj-catalytic trimer exhibited hyperbolic kinetics, with an activation energy similar to that observed for the E. coli catalytic trimer. Homology models of the Mj-PyrB and Mj-PyrI gene products were constructed based on the three-dimensional structures of the homologous E. coli proteins. The residues known to be critical for catalysis, regulation, and formation of the quaternary structure from the well characterized E. coli aspartate transcarbamoylase were compared.

  6. The fatty acid-rich fraction of Eruca sativa (rocket salad) leaf extract exerts antidiabetic effects in cultured skeletal muscle, adipocytes and liver cells.

    Science.gov (United States)

    Hetta, Mona H; Owis, Asmaa I; Haddad, Pierre S; Eid, Hoda M

    2017-12-01

    Eruca sativa Mill. (Brassicaceae), commonly known as rocket salad, is a popular leafy-green vegetable with many health benefits. To evaluate the antidiabetic activities of this plant in major insulin-responsive tissues. Five E. sativa leaf extracts of varying polarity were prepared (aqueous extract, 70% and 95% ethanol extracts, the n-hexane-soluble fraction of the 95% ethanol extract (ES3) and the defatted 95% ethanol extract). Eruca sativa extracts were investigated through a variety of cell-based in vitro bioassays for antidiabetic activities in C2C12 skeletal muscle cells, H4IIE hepatocytes and 3T3-L1 adipocytes. Guided by the results of these bioassays, ES3 was fractionated into the saponifiable (SM) and the unspaonifiable (USM) fractions. Glucose uptake was measured using [ 3 H]-deoxy-glucose, while the effects on hepatic glucose-6-phosphatase (G6Pase) and adipogenesis were assessed using Wako AutoKit Glucose and AdipoRed assays, respectively. ES3 and its SM fraction significantly stimulated glucose uptake with EC 50 values of 8.0 and 5.8 μg/mL, respectively. Both extracts significantly inhibited G6Pase activity (IC 50 values of 4.8 and 9.3 μg/mL, respectively). Moreover, ES3 and SM showed significant adipogenic activities with EC 50 of 4.3 and 6.1 μg/mL, respectively. Fatty acid content of SM was identified by GC-MS. trans-Vaccenic and palmitoleic acids were the major unsaturated fatty acids, while palmitic and azelaic acids were the main saturated fatty acids. These findings indicate that ES3 and its fatty acid-rich fraction exhibit antidiabetic activities in insulin-responsive cell lines and may hence prove useful for the treatment of type 2 diabetes.

  7. The efficacy of a local ascorbic acid-rich food in improving iron absorption from Mexican diets: a field study using stable isotopes.

    Science.gov (United States)

    Diaz, Margarita; Rosado, Jorge L; Allen, Lindsay H; Abrams, Steve; García, Olga P

    2003-09-01

    One potentially sustainable approach to improving iron status at the community level is to encourage the consumption of local ascorbic acid-rich foods, in conjunction with meals high in nonheme iron. The study, conducted in rural Mexico, measured stable isotopes of iron to evaluate the effect on iron absorption of the addition of 25 mg ascorbic acid as agua de limón (limeade) to 2 typical meals per day for 2 wk. Fifteen nonpregnant, nonlactating, iron-deficient (ferritin < 12 microg/L) women (x +/- SD age: 28.3 +/- 7.7 y) fasted overnight and were brought to a community clinic. After an initial blood sample, subjects consumed 0.25 mg (57)Fe with both breakfast and lunch for 14 d. On day 29, another blood sample was taken, and a reference dose of 2.7 mg (58)Fe with 25 mg ascorbic acid was given. For the following 15 d, participants consumed 0.25 mg (57)Fe added to both breakfast and lunch with 25 mg ascorbic acid added to each meal as limeade. A final blood sample was taken on day 59. Iron absorption was calculated from recovery of isotopes in blood obtained 14 d after administration of each isotope. When 25 mg ascorbic acid as limeade was added to test meals twice a day for 2 wk, iron absorption increased significantly (P < 0.001) in every subject: the mean absorption rose from 6.6 +/- 3.0% to 22.9 +/- 12.6%. The consumption of 25 mg ascorbic acid as limeade twice daily with meals substantially improved iron absorption and may improve the iron status of nonpregnant, nonlactating, iron-deficient women.

  8. Acidic peptides enhanced genistein-dependent inhibition of human platelet aggregation: potential protective effect of digestible peptides plus genistein against atherosclerosis.

    Science.gov (United States)

    Borgwardt, Kerstin; Bonifatius, Susanne; Gardemann, Andreas

    2008-08-01

    The leading cause of death in the United States and European countries is coronary heart disease. We hypothesized that the ingestion of soy compounds may not only have beneficial effects on atherosclerotic risk by lowering lipid compounds, but also by reducing platelet aggregability. Therefore, we analyzed in vitro the influence of defined and digestible peptides, frequently found in glycinin and beta-conglycinin as important proteins of soy bean, on platelet aggregation of 180 healthy volunteers with or without the isoflavone genistein by aggregometry and flow cytometry. (i) The predominating share of amino acids and acidic, neutral, and basic di- and tripeptides of up to 2 mmol/L did not modify platelet aggregation induced by collagen, adenosine diphosphate, epinephrine, or arachidonic acid. (ii) Genistein inhibited agonist-induced platelet aggregation dose dependently. (iii) In the presence of the acidic peptides glutamate-glutamate and aspartate-aspartate-aspartate (1 mmol/L each), genistein reduced collagen- and ADP-dependent platelet activation stronger than 250 micromol/L of this isoflavone alone. Other peptides were less effective (eg, glutamate-glutamate-glutamate) or ineffective (eg, asparagine-asparagine). (iv) Glutamate-glutamate-glutamate (1 nmol/L), glutamate-glutamate (1 micromol/L), and aspartate-aspartate-aspartate (1 micromol/L) enhanced the inhibition of genistein on platelet aggregation induced by arachidonic acid. Thus, the results of the present in vitro investigation allow the assumption that nutrition with specific compounds of soy--acidic peptides together with genistein--might protect against coronary atherosclerosis by attenuating platelet activity. In vivo studies are warranted to check this assumption.

  9. Production of aspartic peptidases by Aspergillus spp. using tuna ...

    African Journals Online (AJOL)

    A Kp of 4.5 for ATPS PEG 1450-Pi; in ATPS PEG 8000-Pi, Kp value of the range of 2 to 2.5 was obtained. A purification factor 2 was obtained. The method appears to be suitable as a first step for the purification of these proteins from these complex medium. Key words: Tuna cooked wastewater, aspartic peptidases, aqueous ...

  10. Effects of n-6 and n-3 polyunsaturated acid-rich soybean phosphatidylcholine on membrane lipid profile and cryotolerance of human sperm.

    Science.gov (United States)

    Vireque, Alessandra A; Tata, Alessandra; Silva, Oswaldo F L L O; LoTurco, Edson G; Azzolini, Augusto; Ferreira, Christina R; Dantas, Marilda H Y; Ferriani, Rui A; Reis, Rosana M

    2016-08-01

    To study the effects of n-6 and n-3 polyunsaturated acid-rich soybean phosphatidylcholine (soy-PC) on sperm cryotolerance with regard to sperm membrane lipid profile, membrane surface integrity, and routine semen parameters. Experimental study. University-affiliated tertiary hospital. A total of 20 normospermic fertile men. Semen samples examined for differences in semen parameters, sperm membrane lipid profile, and plasma membrane surface both before and after cryopreservation using basic freezing medium with N-tris(hydroxymethyl)-methyl-2-aminoethane sulfonic acid (TES) and tris-(hydroxymethyl)-aminomethane (TRIS) supplemented with purified soy-PC (TEST-PC) or egg yolk (TEST-Y), both alone or in association (TEST-Y-PC). Conventional semen parameters and membrane lipid profile by matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS). Postthaw sperm cell motility, vitality, and morphology parameters were similar for soy-PC (TEST-PC) and egg yolk (TEST-Y) cryoprotectants. However, sperm exposed to TEST-Y-PC presented better kinetic parameters, which were similar to the original quality of the fresh semen. Human sperm MALDI-MS lipid profiles revealed that the relative abundance of glycerophospholipids of m/z 760.44 [PC (34:1)+H]+, 781.55 [SM (20:0) +Na]+, 784.55 [PC (36:3) +H]+, 806.64 [PC (38:6) +H]+, 807.64 [SM (22:1) +Na]+, and 809.64 [SM (22:0) +Na]+ increased in soy-PC samples (TEST-PC). Nonetheless, only one lipid (m/z 781.55, [SM (20:0) +Na]+) statistically significantly changed when sperm was cryopreserved in TEST-Y-PC. Sphingomyelin was defined as a prospective biomarker of soy-PC treatment, and it could be related to the positive cryoprotective effects of soy-PC in human sperm, opening new perspectives to design of a more efficient synthetic cryoprotectant medium containing purified egg yolk biomolecules combined with soy-PC. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  11. Improved postprandial glycaemic control with insulin Aspart in type 2 diabetic patients treated with insulin

    DEFF Research Database (Denmark)

    Rosenfalck, A M; Thorsby, P; Kjems, L

    2000-01-01

    beta-cell function. In a double-blind, double dummy crossover design, patients attended three study days where the following insulin injections in combination with placebo were given in a random order: IAsp (0.15 IU/kg body weight) immediately before the meal, or insulin Actrapid (0.15 IU......The effect on postprandial blood glucose control of an immediately pre-meal injection of the rapid acting insulin analogue Aspart (IAsp) was compared with that of human insulin Actrapid injected immediately or 30 minutes before a test meal in insulin-treated type 2 diabetic patients with residual....../kg) immediately (Act0) or 30 minutes before (Act-30) a test meal. We studied 25 insulin-requiring type 2 diabetic patients, including 14 males and 11 females, with a mean age of 59.7 years (range, 43-71), body mass index 28.3 kg/m2 (range, 21.9-35.0), HbA1c 8.5% (range, 6.8-10.0), glucagon-stimulated C-peptide 1...

  12. Intramolecular cyclization of aspartic acid residues assisted by three water molecules: a density functional theory study

    Science.gov (United States)

    Takahashi, Ohgi; Kirikoshi, Ryota

    2014-01-01

    Aspartic acid (Asp) residues in peptides and proteins (l-Asp) are known to undergo spontaneous nonenzymatic reactions to form l-β-Asp, d-Asp, and d-β-Asp residues. The formation of these abnormal Asp residues in proteins may affect their three-dimensional structures and hence their properties and functions. Indeed, the reactions have been thought to contribute to aging and pathologies. Most of the above reactions of the l-Asp residues proceed via a cyclic succinimide intermediate. In this paper, a novel three-water-assisted mechanism is proposed for cyclization of an Asp residue (forming a gem-diol precursor of the succinimide) by the B3LYP/6-31 + G(d,p) density functional theory calculations carried out for an Asp-containing model compound (Ace-Asp-Nme, where Ace = acetyl and Nme = NHCH3). The three water molecules act as catalysts by mediating ‘long-range’ proton transfers. In the proposed mechanism, the amide group on the C-terminal side of the Asp residue is first converted to the tautomeric iminol form (iminolization). Then, reorientation of a water molecule and a conformational change occur successively, followed by the nucleophilic attack of the iminol nitrogen on the carboxyl carbon of the Asp side chain to form the gem-diol species. A satisfactory agreement was obtained between the calculated and experimental energetics.

  13. Mapping the conformational free energy of aspartic acid in the gas phase and in aqueous solution

    Science.gov (United States)

    Comitani, Federico; Rossi, Kevin; Ceriotti, Michele; Sanz, M. Eugenia; Molteni, Carla

    2017-04-01

    The conformational free energy landscape of aspartic acid, a proteogenic amino acid involved in a wide variety of biological functions, was investigated as an example of the complexity that multiple rotatable bonds produce even in relatively simple molecules. To efficiently explore such a landscape, this molecule was studied in the neutral and zwitterionic forms, in the gas phase and in water solution, by means of molecular dynamics and the enhanced sampling method metadynamics with classical force-fields. Multi-dimensional free energy landscapes were reduced to bi-dimensional maps through the non-linear dimensionality reduction algorithm sketch-map to identify the energetically stable conformers and their interconnection paths. Quantum chemical calculations were then performed on the minimum free energy structures. Our procedure returned the low energy conformations observed experimentally in the gas phase with rotational spectroscopy [M. E. Sanz et al., Phys. Chem. Chem. Phys. 12, 3573 (2010)]. Moreover, it provided information on higher energy conformers not accessible to experiments and on the conformers in water. The comparison between different force-fields and quantum chemical data highlighted the importance of the underlying potential energy surface to accurately capture energy rankings. The combination of force-field based metadynamics, sketch-map analysis, and quantum chemical calculations was able to produce an exhaustive conformational exploration in a range of significant free energies that complements the experimental data. Similar protocols can be applied to larger peptides with complex conformational landscapes and would greatly benefit from the next generation of accurate force-fields.

  14. Mapping the conformational free energy of aspartic acid in the gas phase and in aqueous solution.

    Science.gov (United States)

    Comitani, Federico; Rossi, Kevin; Ceriotti, Michele; Sanz, M Eugenia; Molteni, Carla

    2017-04-14

    The conformational free energy landscape of aspartic acid, a proteogenic amino acid involved in a wide variety of biological functions, was investigated as an example of the complexity that multiple rotatable bonds produce even in relatively simple molecules. To efficiently explore such a landscape, this molecule was studied in the neutral and zwitterionic forms, in the gas phase and in water solution, by means of molecular dynamics and the enhanced sampling method metadynamics with classical force-fields. Multi-dimensional free energy landscapes were reduced to bi-dimensional maps through the non-linear dimensionality reduction algorithm sketch-map to identify the energetically stable conformers and their interconnection paths. Quantum chemical calculations were then performed on the minimum free energy structures. Our procedure returned the low energy conformations observed experimentally in the gas phase with rotational spectroscopy [M. E. Sanz et al., Phys. Chem. Chem. Phys. 12, 3573 (2010)]. Moreover, it provided information on higher energy conformers not accessible to experiments and on the conformers in water. The comparison between different force-fields and quantum chemical data highlighted the importance of the underlying potential energy surface to accurately capture energy rankings. The combination of force-field based metadynamics, sketch-map analysis, and quantum chemical calculations was able to produce an exhaustive conformational exploration in a range of significant free energies that complements the experimental data. Similar protocols can be applied to larger peptides with complex conformational landscapes and would greatly benefit from the next generation of accurate force-fields.

  15. Single frequency intake of α-linolenic acid rich phytosterol esters attenuates atherosclerosis risk factors in hamsters fed a high fat diet.

    Science.gov (United States)

    Deng, Qianchun; Yu, Xiao; Xu, Jiqu; Kou, Xiuying; Zheng, Mingming; Huang, Fenghong; Huang, Qingde; Wang, Lan

    2016-02-03

    Emerging evidence suggested phytosterol esters (PE) exhibited an advantage over naturally occurring phytosterols in reducing atherosclerosis risk factors due to improved fat solubility and compatibility. However, the effects of dietary patterns of PE on lipid-lowering activity were limited and inconsistent. This study aimed to explore the effects of dose and frequency of α-linolenic acid rich phytosterol esters (ALA-PE) on cholesterol and triglyceride metabolism markers focused on intestinal cholesterol absorption and bioconversion of ALA in liver. Dose-dependency study Male Syrian golden hamsters were fed high-fat diets (HFD) containing low, medium and high dose of ALA-PE (0.72 %, 2.13 % and 6.39 %) for 6 weeks. The high fat diet contained 89.5 % chow diet, 0.2 % cholesterol, 10 % lard and 0.3 % bile salt. Dose-frequency study Male Syrian golden hamsters were provided: (I) 0.4 mL/100 g peanut oil by gavage once a day; (II) 0.4 mL/100 g ALA-PE by gavage once a day; (III) 0.2 mL/100 g ALA-PE by gavage twice a day; (IV) 0.133 mL/100 g ALA-PE by gavage three times a day; (V) 0.1 mL/100 g ALA-PE by gavage four times a day for 6 weeks with a high-fat diet simultaneously. ALA-PE dose-dependently lowered plasma total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) concentrations with a maximal decrease of 42 %, 59 % and 73 %, respectively (p hamsters consumed HFD plus ALA-PE for 1-4 times per day but there were not remarkable differences among different consumption frequencies. No significant changes in plasma antioxidant capacity and lipid peroxidation levels were observed among HFD and HFD plus different doses of ALA-PE groups. The contents of hepatic α-linolenic (ALA), docosapentaenoic (DPA) and docosahexaenoic (DHA) acids were dose-dependently increased in different ALA-PE groups compared to those in HFD group. The abundance of mRNA for intestinal sterol transporters Niemann-Pick C1-Like 1 (NPC1L1), ATP-binding cassette (ABC

  16. Crystal structure of truncated aspartate transcarbamoylase from Plasmodium falciparum.

    Science.gov (United States)

    Lunev, Sergey; Bosch, Soraya S; Batista, Fernando de Assis; Wrenger, Carsten; Groves, Matthew R

    2016-07-01

    The de novo pyrimidine-biosynthesis pathway of Plasmodium falciparum is a promising target for antimalarial drug discovery. The parasite requires a supply of purines and pyrimidines for growth and proliferation and is unable to take up pyrimidines from the host. Direct (or indirect) inhibition of de novo pyrimidine biosynthesis via dihydroorotate dehydrogenase (PfDHODH), the fourth enzyme of the pathway, has already been shown to be lethal to the parasite. In the second step of the plasmodial pyrimidine-synthesis pathway, aspartate and carbamoyl phosphate are condensed to N-carbamoyl-L-aspartate and inorganic phosphate by aspartate transcarbamoylase (PfATC). In this paper, the 2.5 Å resolution crystal structure of PfATC is reported. The space group of the PfATC crystals was determined to be monoclinic P21, with unit-cell parameters a = 87.0, b = 103.8, c = 87.1 Å, α = 90.0, β = 117.7, γ = 90.0°. The presented PfATC model shares a high degree of homology with the catalytic domain of Escherichia coli ATC. There is as yet no evidence of the existence of a regulatory domain in PfATC. Similarly to E. coli ATC, PfATC was modelled as a homotrimer in which each of the three active sites is formed at the oligomeric interface. Each active site comprises residues from two adjacent subunits in the trimer with a high degree of evolutional conservation. Here, the activity loss owing to mutagenesis of the key active-site residues is also described.

  17. Assembly of catalytic subunits of aspartate transcarbamoylase from Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Burns, D.L.; Schachman, H.K.

    1980-10-01

    Although extensive studies have been conducted on the assembly of the allosteric enzyme, aspartate transcarbamoylase (ATCase) from isolate, intact catalytic (C) and regulatory (R) subunits, there has been little research on the formation of these subunits from individual catalytic (c) and regulatory (r) polypeptide chains. Such studies would be useful for evaluating the strengths of the interchain bonding domains within the subunits just as earlier experiments provided valuable data regarding interactions between the subunits in ATCase. The intact enzyme comprising two C trimers and three R dimers is designated as C/sub 2/R/sub 3/ or c/sub 6/r/sub 6/.

  18. Insulin degludec aspart: One-year real world experience

    OpenAIRE

    Sanjay Kalra; Manash P Baruah

    2016-01-01

    Background: This retrospective analysis describes the use of insulin degludec aspart (IDegAsp) in India. Material and Methods: All subjects who had received IDegAsp for 52 weeks at two endocrine centers were included in this study. Results: Forty-eight subjects (40 men), with mean age of 54.33 ? 9.63 years and mean duration of diabetes of 6.33 ? 2.96 years, started IDegAsp as insulin of initiation (16), as an intensification regime (4), as de-escalation from basal-bolus therapy (16), or as sw...

  19. Augmenting in vitro osteogenesis of a glycine-arginine-glycine-aspartic-conjugated oxidized alginate-gelatin-biphasic calcium phosphate hydrogel composite and in vivo bone biogenesis through stem cell delivery.

    Science.gov (United States)

    Linh, Nguyen Tb; Paul, Kallyanashis; Kim, Boram; Lee, Byong-Taek

    2016-11-01

    A functionally modified peptide-conjugated hydrogel system was fabricated with oxidized alginate/gelatin loaded with biphasic calcium phosphate to improve its biocompatibility and functionality. Sodium alginate was treated by controlled oxidation to transform the cis-diol group into an aldehyde group in a controlled manner, which was then conjugated to the amine terminus of glycine-arginine-glycine-aspartic. Oxidized alginate glycine-arginine-glycine-aspartic was then combined with gelatin-loaded biphasic calcium phosphate to form a hydrogel of composite oxidized alginate/gelatin/biphasic calcium phosphate that displayed enhanced human adipose stem cell adhesion, spreading and differentiation. 1H nuclear magnetic resonance and electron spectroscopy for chemical analysis confirmed that the glycine-arginine-glycine-aspartic was successfully grafted to the oxidized alginate. Co-delivery of glycine-arginine-glycine-aspartic and human adipose stem cell in a hydrogel matrix was studied with the results indicating that hydrogel incorporated modified with glycine-arginine-glycine-aspartic and seeded with human adipose stem cell enhanced osteogenesis in vitro and bone formation in vivo. © The Author(s) 2016.

  20. Cisplatin-Rich Polyoxazoline-Poly(aspartic acid) Supramolecular Nanoparticles.

    Science.gov (United States)

    Zhang, Peng; Yuan, Kangjun; Li, Cheng; Zhang, Xiaoke; Wu, Wei; Jiang, Xiqun

    2017-12-01

    Cisplatin-rich supramolecular nanoparticles are constructed through the supramolecular inclusion interaction between the admantyl (Ad)-terminated poly(aspartic acid) (Ad-P(Asp)) and the β-cyclodextrin (β-CD)-terminated poly(2-methyl-2-oxazoline). In the formation of the nanoparticles, the β-CD/admantane inclusion complex integrates poly(2-methyl-2-oxazoline) and poly(aspartic acid) chains to form pseudoblock copolymers, followed by the coordination between carboxyl groups in P(Asp) block and cisplatin. This coordination interaction drives the formation of nanoparticle and enables cisplatin incorporated into the nanoparticles. The spherical cisplatin-rich supramolecular nanoparticles have 53% cisplatin-loading content, good stability, and effective inhibition of the cell proliferation when it is tested in H22 cancer cells. Near-infrared fluorescence imaging of tumor bearing mice reveals that the cisplatin-rich nanoparticles can target the tumor in vivo effectively. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Evaluation of the therapeutic effect of Nigella sativa crude oil and its blend with omega-3 fatty acid-rich oils in a modified hepatorenal syndrome model in rats

    OpenAIRE

    Al-Okbi, S. Y.; Mohamed, D. A.; Hamed, T. E.; A. E. Edris

    2015-01-01

    In the present study, the hepato and reno-protective effect of Nigella sativa crude oil and its binary blend with omega-3 fatty acid-rich oils (fish and flaxseed oils) was studied in a modified hepatorenal syndrome model (MHRS) in rats. MHRS was induced through feeding a high fructose diet followed by an intraperitoneal injection of galactosamine hydrochloride. Nigella oil and its different blends were given as a daily oral dose to MHRS rats. Two control groups of MHRS and normal healthy rats...

  2. Novel cell penetrating peptides with multiple motifs composed of RGD and its analogs.

    Science.gov (United States)

    Mokhtarieh, Amir Abbas; Kim, Semi; Lee, Yunhee; Chung, Bong Hyun; Lee, Myung Kyu

    2013-03-08

    Cell penetrating peptides (CPPs) have been used to transport macromolecules into cells. Most CPPs have properties such as a strong polycationic charge, amphipathic basic, and hydrophobicity. In this study, we designed the peptides with multiple motifs composed of RGD and its analogs to induce integrin-mediated endocytosis as well as endosomal escape by forming an amphipathic helix in acidic endosomes. These peptides were proved less toxic to animal cells than those without acidic residues. Unexpectedly, peptide conjugated liposomes could penetrate into cells regardless of integrins. The replacement of all aspartic acids by glutamic acids did not prevent the peptide-mediated liposome uptake, and the higher basic and leucine contents enhanced the gene silencing activity of siRNA encapsulated in the liposomes. The peptide is considered to be a new type of CPP which can be used for drug delivery. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Strains of Lactococcus lactis with a partial pyrimidine requirement show sensitivity toward aspartic acid

    DEFF Research Database (Denmark)

    Wadskov-Hansen, Steen Lyders Lerche; Martinussen, Jan

    2009-01-01

    The growth rate of the widely used laboratory strain Lactococcus lactis subsp. cremoris LM0230 was reduced if aspartic acid were present in the growth medium. The strain LM0230 is a plasmid- and phage-cured derivative of L. lactis subsp. cremoris C2, the ancestor of the original dairy isolate L...... with the wild-type strain, and this varied with the concentration of aspartic acid. The observed effect of aspartate could be explained by the accumulation of the toxic pyrimidine de novo pathway intermediate, carbamoyl aspartate. Assays of the pyrimidine biosynthetic enzymes of L. lactis LM0230 showed....... lactis subsp. cremoris NCDO712. The growth of both C2 and NCDO712 was unaffected by exogenous aspartate. Also, the growth rate of the pyrimidine auxotrophic mutants of L. lactis was affected by exogenous aspartate. The maximum observed reduction in the growth rate was similar to 35% when compared...

  4. Human peptide transporters

    DEFF Research Database (Denmark)

    Nielsen, Carsten Uhd; Brodin, Birger; Jørgensen, Flemming Steen

    2002-01-01

    Peptide transporters are epithelial solute carriers. Their functional role has been characterised in the small intestine and proximal tubules, where they are involved in absorption of dietary peptides and peptide reabsorption, respectively. Currently, two peptide transporters, PepT1 and PepT2...... to peptide transporters, as well as their role in drug delivery and in potential future drug design and targeted tissue delivery of peptides and peptidomimetics....

  5. Critical requirement for aspartic acid at position 82 of myelin basic protein 73-86 for recruitment of V beta 8.2+ T cells and encephalitogenicity in the Lewis rat.

    Science.gov (United States)

    Smeltz, R B; Wauben, M H; Wolf, N A; Swanborg, R H

    1999-01-15

    We synthesized single amino acid-substituted peptide analogues of guinea pig myelin basic protein (MBP) 73-86 to study the importance of aspartic acid at residue 82 (QKSQRSQDENPV), which previous reports have suggested is a critical TCR contact residue. Whereas the wild-type 73-86 peptide elicited severe experimental autoimmune encephalomyelitis (EAE) in the Lewis rat, none of the peptide analogues with substitutions at position 82 were capable of inducing EAE. The inability to cause EAE was not due to a failure to bind MHC or to elicit T cell proliferation and cytokine secretion. T cells specific for MBP73-86 did not cross-react with any of the analogues tested, further indicating the importance of this residue in T cell responses to 73-86. Analysis by flow cytometry showed that only the wild-type 73-86 peptide was capable of recruiting V beta 8.2+ T cells, which have been shown previously to be important for disease induction. Reduced expression of the V beta 8.2 TCR was also seen in Lewis rats protected from EAE by coimmunization of MBP73-86 with 73-86(82D-->A), despite an increase in cytokine production when both peptides were present during in vitro culture. The data indicate that aspartic acid 82 is a critical TCR contact residue and is required for the recruitment of V beta 8.2+ T cells and the encephalitogenic activity of MBP73-86.

  6. Intersubunit communication in the dihydroorotase-aspartate transcarbamoylase complex of Aquifex aeolicus: Intersubunit Communication in a Pyrimidine Biosynthetic Complex

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Hedeel Guy [Department of Chemistry, Eastern Michigan University, Ypsilanti Michigan 48197; Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit Michigan 48201; Fernando, Roshini [Department of Chemistry, Eastern Michigan University, Ypsilanti Michigan 48197; Vaishnav, Asmita [Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit Michigan 48201; Kotichukkala, Mahalakshmi [Department of Chemistry, Eastern Michigan University, Ypsilanti Michigan 48197; Heyl, Deborah [Department of Chemistry, Eastern Michigan University, Ypsilanti Michigan 48197; Martin, Philip D. [Department of Chemistry, Wayne State University, Detroit Michigan 48202; Hachem, Fatme [Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit Michigan 48201; Brunzelle, Joseph S. [Life Sciences Collaborative Access Team, Northwestern University, Center for Synchrotron Research, Argonne Illinois 60439; Edwards, Brian F. P. [Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit Michigan 48201; Evans, David R. [Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit Michigan 48201

    2013-12-19

    Aspartate transcarbamoylase and dihydroorotase, enzymes that catalyze the second and third step in de novo pyrimidine biosynthesis, are associated in dodecameric complexes in Aquifex aeolicus and many other organisms. The architecture of the dodecamer is ideally suited to channel the intermediate, carbamoyl aspartate from its site of synthesis on the ATC subunit to the active site of DHO, which catalyzes the next step in the pathway, because both reactions occur within a large, internal solvent-filled cavity. Channeling usually requires that the reactions of the enzymes are coordinated so that the rate of synthesis of the intermediate matches its rate of utilization. The linkage between the ATC and DHO subunits was demonstrated by showing that the binding of the bisubstrate analog, N-phosphonacetyl-L-aspartate to the ATC subunit inhibits the activity of the distal DHO subunit. Structural studies identified a DHO loop, loop A, interdigitating between the ATC domains that would be expected to interfere with domain closure essential for ATC catalysis. Mutation of the DHO residues in loop A that penetrate deeply between the two ATC domains inhibits the ATC activity by interfering with the normal reciprocal linkage between the two enzymes. Moreover, a synthetic peptide that mimics that part of the DHO loop that binds between the two ATC domains was found to be an allosteric or noncompletive ATC inhibitor (Ki = 22 μM). A model is proposed suggesting that loop A is an important component of the functional linkage between the enzymes.

  7. Peptidyl prolyl isomerase Pin1-inhibitory activity of D-glutamic and D-aspartic acid derivatives bearing a cyclic aliphatic amine moiety.

    Science.gov (United States)

    Nakagawa, Hidehiko; Seike, Suguru; Sugimoto, Masatoshi; Ieda, Naoya; Kawaguchi, Mitsuyasu; Suzuki, Takayoshi; Miyata, Naoki

    2015-12-01

    Pin1 is a peptidyl prolyl isomerase that specifically catalyzes cis-trans isomerization of phosphorylated Thr/Ser-Pro peptide bonds in substrate proteins and peptides. Pin1 is involved in many important cellular processes, including cancer progression, so it is a potential target of cancer therapy. We designed and synthesized a novel series of Pin1 inhibitors based on a glutamic acid or aspartic acid scaffold bearing an aromatic moiety to provide a hydrophobic surface and a cyclic aliphatic amine moiety with affinity for the proline-binding site of Pin1. Glutamic acid derivatives bearing cycloalkylamino and phenylthiazole groups showed potent Pin1-inhibitory activity comparable with that of known inhibitor VER-1. The results indicate that steric interaction of the cyclic alkyl amine moiety with binding site residues plays a key role in enhancing Pin1-inhibitory activity. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Conformational behavior of ionic self-complementary peptides.

    Science.gov (United States)

    Altman, M; Lee, P; Rich, A; Zhang, S

    2000-06-01

    Several de novo designed ionic peptides that are able to undergo conformational change under the influence of temperature and pH were studied. These peptides have two distinct surfaces with regular repeats of alternating hydrophilic and hydrophobic side chains. This permits extensive ionic and hydrophobic interactions resulting in the formation of stable beta-sheet assemblies. The other defining characteristic of this type of peptide is a cluster of negatively charged aspartic or glutamic acid residues located toward the N-terminus and positively charged arginine or lysine residues located toward the C-terminus. This arrangement of charge balances the alpha-helical dipole moment (C --> N), resulting in a strong tendency to form stable alpha-helices as well. Therefore, these peptides can form both stable alpha-helices and beta-sheets. They are also able to undergo abrupt structural transformations between these structures induced by temperature and pH changes. The amino acid sequence of these peptides permits both stable beta-sheet and alpha-helix formation, resulting in a balance between these two forms as governed by the environment. Some segments in proteins may also undergo conformational changes in response to environmental changes. Analyzing the plasticity and dynamics of this type of peptide may provide insight into amyloid formation. Since these peptides have dynamic secondary structure, they will serve to refine our general understanding of protein structure.

  9. Phenolic compounds from Miconia myriantha inhibiting Candida aspartic proteases.

    Science.gov (United States)

    Li, X C; Jacob, M R; Pasco, D S; ElSohly, H N; Nimrod, A C; Walker, L A; Clark, A M

    2001-10-01

    Assay-guided fractionation of the ethanol extract of the twigs and leaves of Miconia myriantha yielded two new compounds, mattucinol-7-O-[4' ',6' '-O-(S)-hexahydroxydiphenoyl]-beta-D-glucopyranoside (1) and mattucinol-7-O-[4' ',6' '-di-O-galloyl]-beta-D-glucopyranoside (2), along with mattucinol-7-O-beta-D-glucopyranoside (3), ellagic acid (4), 3,3'-di-O-methyl ellagic acid-4-O-beta-D-xylopyranoside, and gallic acid. Complete (1)H and (13)C NMR assignments of compound 1, which possesses a hexahydroxydiphenoyl unit, were achieved using the HMBC technique optimized for small couplings to enhance the four-bond and two-bond H/C correlations. Compounds 1 and 4 showed inhibitory effects against Candida albicans secreted aspartic proteases, with IC(50) of 8.4 and 10.5 microM, respectively.

  10. Aspartate aminotransferase activity in human healthy and inflamed dental pulps.

    Science.gov (United States)

    Spoto, G; Fioroni, M; Rubini, C; Tripodi, D; Perinetti, G; Piattelli, A

    2001-06-01

    Aspartate aminotransferase (AST) seems to be an important mediator of inflammatory processes. Its role in the progression and detection of inflammatory periodontal disease has been increasingly recognized in recent years. In the present study AST activity was analyzed in normal healthy human dental pulps, in reversible pulpitis, and in irreversible pulpitis. Enzymatic AST activity showed that the control values for the healthy pulps were 4.8 +/- 0.7 units/mg of pulp tissue. In reversible pulpitis specimens the AST activity increased to 7.98 +/- 2.1 units/mg of pulp tissue. In irreversible pulpitis specimens the values decreased to 2.28 +/- 1.7 units/mg of pulp tissue. Differences between the groups (control versus reversible pulpitis and reversible pulpitis versus irreversible pulpitis) were statistically significant (p = 0.0015). These results could point to a role of AST in the early events that lead to development of pulpal inflammation.

  11. N-methyl-D-aspartic acid receptor agonists

    DEFF Research Database (Denmark)

    Madsen, U; Frydenvang, Karla Andrea; Ebert, B

    1996-01-01

    (R,S)-2-Amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid [(R,S)-AMAA, 4] is a potent and selective agonist at the N-methyl-D-aspartic acid (NMDA) subtype of excitatory amino acid receptors. Using the Ugi "four-component condensation" method, the two diastereomers (2R)- and (2S)-2-[3-(benzyloxy......) showed peak affinity for [3H]AMPA receptor sites (IC50 = 72 +/- 13 microM) and was shown to be a more potent inhibitor of [3H]CPP binding (IC50 = 3.7 +/- 1.5 microM) than (S)-AMAA (9) (IC50 = 61 +/- 6.4 microM). Neither enantiomer of AMAA affected [3H]kainic acid receptor binding significantly...

  12. Anti-N-methyl-D-aspartate receptor encephalitis in China

    Directory of Open Access Journals (Sweden)

    Li Li

    2014-06-01

    Full Text Available N-methyl-D-aspartate receptors (NMDARs are mainly distributed in the central nervous system, and play important roles in the mechanisms of learning and memory. A newly discovered disease caused by autoantibody to NMDAR has been described, and is called anti-NMDAR encephalitis. Patients with this disease often suffer from mental disorders, seizures and other encephalitis-like symptoms. Accumulated data suggests that the severity of the disease makes early diagnosis very important. Accurately detecting the autoantibody to NMDAR is considered to be the gist of diagnosis. Good prognosis is predicted in most patients, when treated properly. Immunotherapy is preferred in most cases. In China, this disease has been reported only for a few years, but sporadic case reports are also helpful for profiling.

  13. Anti-N-Methyl-d-Aspartate Receptor Encephalitis

    Directory of Open Access Journals (Sweden)

    Te-Yu Hung

    2011-12-01

    Full Text Available Anti-N-methyl-d-aspartate (NMDA receptor encephalitis is a treatment-responsive encephalitis associated with anti-NMDA receptor antibodies, which bind to the NR1/NR2 heteromers of the NMDA receptors. It is a highly characteristic syndrome evolving in five stages: the prodromal phase (viral infection-like symptoms, psychotic phase, unresponsive phase, hyperkinetic phase, and gradual recovery phase. It has been considered as a paraneoplastic syndrome usually affecting childbearing-age female with ovarian tumors; however, recent reports suggest a much higher incidence of nonparaneoplastic cases in children. We report a 14-year-old girl with anti-NMDA receptor encephalitis without a detectable tumor who showed a nearly complete recovery after intensive immunotherapy.

  14. Hydroxyproline-induced Helical Disruption in Conantokin Rl-B Affects Subunit-selective Antagonistic Activities toward Ion Channels of N-Methyl-d-aspartate Receptors*

    Science.gov (United States)

    Kunda, Shailaja; Yuan, Yue; Balsara, Rashna D.; Zajicek, Jaroslav; Castellino, Francis J.

    2015-01-01

    Conantokins are ∼20-amino acid peptides present in predatory marine snail venoms that function as allosteric antagonists of ion channels of the N-methyl-d-aspartate receptor (NMDAR). These peptides possess a high percentage of post-/co-translationally modified amino acids, particularly γ-carboxyglutamate (Gla). Appropriately spaced Gla residues allow binding of functional divalent cations, which induces end-to-end α-helices in many conantokins. A smaller number of these peptides additionally contain 4-hydroxyproline (Hyp). Hyp should prevent adoption of the metal ion-induced full α-helix, with unknown functional consequences. To address this disparity, as well as the role of Hyp in conantokins, we have solved the high resolution three-dimensional solution structure of a Gla/Hyp-containing 18-residue conantokin, conRl-B, by high field NMR spectroscopy. We show that Hyp10 disrupts only a small region of the α-helix of the Mn2+·peptide complex, which displays cation-induced α-helices on each terminus of the peptide. The function of conRl-B was examined by measuring its inhibition of NMDA/Gly-mediated current through NMDAR ion channels in mouse cortical neurons. The conRl-B displays high inhibitory selectivity for subclasses of NMDARs that contain the functionally important GluN2B subunit. Replacement of Hyp10 with N8Q results in a Mg2+-complexed end-to-end α-helix, accompanied by attenuation of NMDAR inhibitory activity. However, replacement of Hyp10 with Pro10 allowed the resulting peptide to retain its inhibitory property but diminished its GluN2B specificity. Thus, these modified amino acids, in specific peptide backbones, play critical roles in their subunit-selective inhibition of NMDAR ion channels, a finding that can be employed to design NMDAR antagonists that function at ion channels of distinct NMDAR subclasses. PMID:26048991

  15. Dihydroorotase from the Hyperthermophile Aquifiex aeolicus Is Activated by Stoichiometric Association with Aspartate Transcarbamoylase and Forms a One-Pot Reactor for Pyrimidine Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengfei; Martin, Philip D.; Purcarea, Cristina; Vaishnav, Asmita; Brunzelle, Joseph S.; Fernando, Roshini; Guy-Evans, Hedeel I.; Evans, David R.; Edwards, Brian F.P.; (WSU-MED); (IB-Bucharest); (NWU); (E.Mich.U.)

    2009-08-14

    In prokaryotes, the first three enzymes in pyrimidine biosynthesis, carbamoyl phosphate synthetase (CPS), aspartate transcarbamoylase (ATC), and dihydroorotase (DHO), are commonly expressed separately and either function independently (Escherichia coli) or associate into multifunctional complexes (Aquifex aeolicus). In mammals the enzymes are expressed as a single polypeptide chain (CAD) in the order CPS-DHO-ATC and associate into a hexamer. This study presents the three-dimensional structure of the noncovalent hexamer of DHO and ATC from the hyperthermophile A. aeolicus at 2.3 {angstrom} resolution. It is the first structure of any multienzyme complex in pyrimidine biosynthesis and is a possible model for the core of mammalian CAD. The structure has citrate, a near isosteric analogue of carbamoyl aspartate, bound to the active sites of both enzymes. Three active site loops that are intrinsically disordered in the free, inactive DHO are ordered in the complex. The reorganization also changes the peptide bond between Asp153, a ligand of the single zinc atom in DHO, and Gly154, to the rare cis conformation. In the crystal structure, six DHO and six ATC chains form a hollow dodecamer, in which the 12 active sites face an internal reaction chamber that is approximately 60 {angstrom} in diameter and connected to the cytosol by narrow tunnels. The entrances and the interior of the chamber are both electropositive, which suggests that the architecture of this nanoreactor modifies the kinetics of the bisynthase, not only by steric channeling but also by preferential escape of the product, dihydroorotase, which is less negatively charged than its precursors, carbamoyl phosphate, aspartate, or carbamoyl aspartate.

  16. Antimicrobial peptides in action

    NARCIS (Netherlands)

    Leontiadou, Hari; Mark, Alan E.; Marrink, Siewert J.

    2006-01-01

    Molecular dynamics simulations of the magainin MG-H2 peptide interacting with a model phospholipid membrane have been used to investigate the mechanism by which antimicrobial peptides act. Multiple copies of the peptide were randomly placed in solution close to the membrane. The peptide readily

  17. Demyelinating disease and anti-N-methyl-D-aspartate receptor immunoglobulin G antibodies: a case report.

    Science.gov (United States)

    Waschbisch, Anne; Kallmünzer, Bernd; Schwab, Stefan; Gölitz, Philipp; Vincent, Angela; Lee, De-Hyung; Linker, Ralf A

    2014-12-23

    Anti-N-methyl-D-aspartate receptor immunoglobulin G antibodies directed against the GluN1 subunit are considered highly specific for anti-N-methyl-D-aspartate receptor encephalitis, a severe clinical syndrome characterized by seizures, psychiatric symptoms, orofacial dyskinesia and autonomic dysfunction. Here we report a 33 year old Caucasian male patient with clinically definite multiple sclerosis who was found to be positive for anti-N-methyl-D-aspartate receptor antibodies. Rituximab therapy was initiated. On the 18 months follow-up visit the patient was found to be clinically stable, without typical signs of anti-N-methyl-D-aspartate receptor encephalitis. Our findings add to the growing evidence for a possible association between anti-N-methyl-D-aspartate receptor encephalitis and demyelinating diseases.

  18. N-acetyl-aspartate, total creatine, and myo-inositol in the epileptogenic human hippocampus.

    Science.gov (United States)

    Petroff, Ognen A C; Errante, Laura D; Kim, Jung H; Spencer, Dennis D

    2003-05-27

    Mesial temporal lobe epilepsy (mTLE) is characterized by hippocampal atrophy, decreased N-acetyl-aspartate, and a low N-acetyl-aspartate/total creatine ratio, often attributed to neuron loss and gliosis. Qualitative studies reported that N-acetyl-aspartate content was significantly lower in hippocampal sclerosis. It was proposed to measure the effects of neuron loss and gliosis on the hippocampal content of N-acetyl-aspartate, total creatine, and myo-inositol in mTLE. Twenty hippocampal specimens were obtained during temporal lobectomy and frozen quickly. Perchloric acid extracts of the small metabolites were prepared and analyzed by proton MRS at 11.75 T. Adjacent samples were used for cell counts. There were no significant associations between hippocampal neuron loss and the cellular content of N-acetyl-aspartate, total creatine, or myo-inositol, despite more than a threefold difference in neuron loss and a twofold increase in glial density. Metabolite concentrations varied two- to fourfold. Variation in the cellular content of total creatine accounted for more than three-quarters of the rank-order variance of the N-acetyl-aspartate concentrations. There were no associations between myo-inositol and N-acetyl-aspartate or total creatine. Overall, mean N-acetyl-aspartate levels were below those reported by in vivo MRS studies of control subjects. These data suggest that decreased N-acetyl-aspartate in mesial temporal lobe epilepsy reflects altered mitochondrial metabolism, not merely neuron loss or gliosis. It is hypothesized that the altered N-acetyl-aspartate and creatine metabolism could reflect mitochondrial dysfunction or proliferation of immature glial cells that could contribute to the epileptogenic state.

  19. Interaction Mechanism and Clustering among RGD Peptides and Integrins.

    Science.gov (United States)

    Dong, Xiuli; Yu, Yuping; Wang, Qi; Xi, Ying; Liu, Yingchun

    2017-05-01

    Peptides with an exposed arginine-glycine-aspartate (Arg-Gly-Asp, RGD) sequence targeting the integrin αV β3 play an important role in targeted anticancer drug delivery. The interaction of multiple RGD-containing peptides and two αV β3 molecules was studied via MD simulation. Results revealed that not all six RGD-containing peptides interact with αV β3 and interaction strengths differed among the peptides. The specific identification sites included the guanidine group of the ARG residue in the RGD peptide and the carboxyl group of the ASP residue in integrin αV β3 . Therefore, formation of a salt bridge between ARGRGD and the ASP residue was the main mechanism of interaction. H-bonds also played an important role in the observed interaction. The interaction between RGD-containing peptides and αV β3 was influenced by two factors: the relative orientation and distance between these groups. The RGD cluster, which could markedly increase the number of absorbed RGD monomers and enhance the cellular uptake of nano-medicines, was observed in this system. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Supermacroporous chemically cross-linked poly(aspartic acid) hydrogels.

    Science.gov (United States)

    Gyarmati, Benjámin; Mészár, E Zsuzsanna; Kiss, Lóránd; Deli, Mária A; László, Krisztina; Szilágyi, András

    2015-08-01

    Chemically cross-linked poly(aspartic acid) (PASP) gels were prepared by a solid-liquid phase separation technique, cryogelation, to achieve a supermacroporous interconnected pore structure. The precursor polymer of PASP, polysuccinimide (PSI) was cross-linked below the freezing point of the solvent and the forming crystals acted as templates for the pores. Dimethyl sulfoxide was chosen as solvent instead of the more commonly used water. Thus larger temperatures could be utilized for the preparation and the drawback of increase in specific volume of water upon freezing could be eliminated. The morphology of the hydrogels was characterized by scanning electron microscopy and interconnectivity of the pores was proven by the small flow resistance of the gels. Compression tests also confirmed the interconnected porous structure and the complete re-swelling and shape recovery of the supermacroporous PASP hydrogels. The prepared hydrogels are of interest for several biomedical applications as scaffolding materials because of their cytocompatibility, controllable morphology and pH-responsive character. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Casablanca cohort of the A1chieve study.

    Science.gov (United States)

    Farouqi, Ahmed; Chadli, Asmae

    2013-11-01

    The A1chieve, a multicentric (28 countries), 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726) in routine clinical care across four continents. Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Casablanca, Morocco. A total of 495 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 231), insulin detemir (n = 151), insulin aspart (n = 19), basal insulin plus insulin aspart (n = 53) and other insulin combinations (n = 41). At baseline glycaemic control was poor for both insulin naïve (mean HbA1c: 10.2%) and insulin user (mean HbA1c: 9.4%) groups. After 24 weeks of treatment, both groups showed improvement in HbA1c (insulin naïve: -2.3%, insulin users: -1.8%). Major hypoglycaemia was observed in the insulin naïve group after 24 weeks. SADRs were reported in 1.2% of insulin naïve and 2.1% of insulin user groups. Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  2. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Maharashtra cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Uday Phadke

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Maharashtra, India. Results: A total of 3069 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 2115, insulin detemir (n = 461, insulin aspart (n = 333, basal insulin plus insulin aspart (n = 92 and other insulin combinations (n = 61. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 8.8 and insulin user (mean HbA 1 c: 9.1% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −1.4%, insulin users: −1.4%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  3. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Kerala cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Sreejith N Kumar

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Kerala, India. Results: A total of 1732 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 1203, insulin detemir (n = 212, insulin aspart (n = 312, basal insulin plus insulin aspart (n = 1 and other insulin combinations (n = 1. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.0% and insulin user (mean HbA 1 c: 8.3% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −2.4%, insulin users: −0.5%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  4. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Kolkata cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Anirban Majumder

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Kolkata, India. Results: A total of 576 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 417, insulin detemir (n = 70, insulin aspart (n = 55, basal insulin plus insulin aspart (n = 19 and other insulin combinations (n = 15. At baseline, glycaemic control was poor for both insulin naïve (mean HbA 1 c: 8.3% and insulin user (mean HbA 1 c: 8.6% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −1.3%, insulin users: −1.4%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  5. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Mumbai cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    P G Talwalkar

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Mumbai, India. Results: A total of 2112 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 1561, insulin detemir (n = 313, insulin aspart (n = 144, basal insulin plus insulin aspart (n = 53 and other insulin combinations (n = 41. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 8.7% and insulin user (mean HbA 1 c: 9.2% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −1.4%, insulin users: −1.8%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  6. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Haryana cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Haryana, India. Results: A total of 345 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 236, insulin detemir (n = 66, insulin aspart (n = 28, basal insulin plus insulin aspart (n = 1 and other insulin combinations (n = 14. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.7% and insulin user (mean HbA 1 c: 10.5% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −3.9%, insulin users: −3.3%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  7. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Chennai cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    J S Kumar

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Chennai, India. Results: A total of 1334 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 983, insulin detemir (n = 205, insulin aspart (n = 42, basal insulin plus insulin aspart (n = 41 and other insulin combinations (n = 63. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.4% and insulin users (mean HbA 1 c: 9.3% groups. After 24 weeks of treatment, both groups showed improvement in HbA 1 c (insulin naïve: −2.1%, insulin users: −1.9%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  8. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Delhi cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Sudhir Tripathi

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Delhi, India. Results: A total of 2242 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 1515, insulin detemir (n = 521, insulin aspart (n = 176, basal insulin plus insulin aspart (n = 11 and other insulin combinations (n = 19. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.0% and insulin user (mean HbA 1 c: 11.0% groups. After 24 weeks of treatment both the groups showed improvement in HbA 1 c (insulin naïve: −3.1%, insulin users: −3.6%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  9. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Casablanca cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Ahmed Farouqi

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Casablanca, Morocco. Results: A total of 495 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 231, insulin detemir (n = 151, insulin aspart (n = 19, basal insulin plus insulin aspart (n = 53 and other insulin combinations (n = 41. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.2% and insulin user (mean HbA 1 c: 9.4% groups. After 24 weeks of treatment, both groups showed improvement in HbA 1 c (insulin naïve: −2.3%, insulin users: −1.8%. Major hypoglycaemia was observed in the insulin naïve group after 24 weeks. SADRs were reported in 1.2% of insulin naïve and 2.1% of insulin user groups. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  10. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Kuwait cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Alaa Daban

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Kuwait. Results: A total of 1185 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 472, insulin detemir (n = 472, insulin aspart (n = 4, basal insulin plus insulin aspart (n = 188 and other insulin combinations (n = 48. At baseline, glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.8% and insulin user (mean HbA 1 c: 9.4% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −2.4%, insulin users: −1.7%. No major hypoglycaemic episodes were observed at 24 weeks. SADR was reported in 0.1% of insulin users. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  11. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Oman cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Mustafa Al Abousi

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Oman. Results: A total of 349 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 121, insulin detemir (n = 171, insulin aspart (n = 2, basal insulin plus insulin aspart (n = 38 and other insulin combinations (n = 17. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.2% and insulin user (mean HbA 1 c: 8.8% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −2.1%, insulin users: −1.6%. SADRs including major hypoglycaemic events did not occur in the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia and no weight gain.

  12. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Gujarat cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Banshi Saboo

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Gujarat, India. Results: A total of 812 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 502, insulin detemir (n = 89, insulin aspart (n = 155, basal insulin plus insulin aspart (n = 45 and other insulin combinations (n = 21. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 8.9% and insulin user (mean HbA 1 c: 9.1% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −2.2%, insulin users: −2.5%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  13. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Marrakech cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    El Ansari Nawal

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Marrakech, Morocco. Results: A total of 196 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 71, insulin detemir (n = 83, insulin aspart (n = 5, basal insulin plus insulin aspart (n = 14 and other insulin combinations (n = 23. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.3% and insulin user (mean HbA 1 c: 9.3% groups. After 24 weeks of treatment, both the study groups showed improvement in HbA 1 c (insulin naïve: −2.3%, insulin users: −1.9%. SADR′s including major hypoglycaemic events did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  14. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Bangalore cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    L Srinivasa Murthy

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Bangalore, India. Results: A total of 1533 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 1262, insulin detemir (n = 165, insulin aspart (n = 86, basal insulin plus insulin aspart (n = 11 and other insulin combinations (n = 2. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.2% and insulin users (mean HbA 1 c: 8.8% groups. After 24 weeks of treatment, both groups showed improvement in HbA 1 c (insulin naïve: −1.3%, insulin users: −1.5%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  15. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Punjab cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Parminder Singh

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Punjab, India. Results: A total of 655 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 587, insulin detemir (n = 28, insulin aspart (n = 24, basal insulin plus insulin aspart (n = 13 and other insulin combinations (n = 3. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.1% and insulin user (mean HbA 1 c: 9.1% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −0.8%, insulin users: −1.0%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  16. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Agadir cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Hicham Boussouf

    2013-01-01

    Full Text Available Background: A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Agadir, Morocco. Results: A total of 201 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 98, insulin detemir (n = 54, insulin aspart (n = 8, basal insulin plus insulin aspart (n = 8 and other insulin combinations (n = 33. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.7% and insulin user (mean HbA 1 c: 9.1% groups. After 24 weeks of treatment, both groups showed improvement in HbA 1 c (insulin naïve: −2.7%, insulin users: −1.3%. No major hypoglycaemia was observed at 24 weeks. SADRs were reported in 1.5% of insulin users. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  17. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Gujarat cohort of the A1chieve study.

    Science.gov (United States)

    Saboo, Banshi; Patel, Mayur

    2013-11-01

    The A1chieve, a multicentric (28 countries), 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726) in routine clinical care across four continents. Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Gujarat, India. A total of 812 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 502), insulin detemir (n = 89), insulin aspart (n = 155), basal insulin plus insulin aspart (n = 45) and other insulin combinations (n = 21). At baseline glycaemic control was poor for both insulin naïve (mean HbA1c: 8.9%) and insulin user (mean HbA1c: 9.1%) groups. After 24 weeks of treatment, both the groups showed improvement in HbA1c (insulin naïve: -2.2%, insulin users: -2.5%). SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  18. Engineering of the aspartate family biosynthetic pathway in barley (Hordeum vulgare L.) by transformation with heterologous genes encoding feed-back-insensitive aspartate kinase and dihydrodipicolinate synthase

    DEFF Research Database (Denmark)

    Brinch-Pedersen, Henrik; Galili, G; Knudsen, S

    1996-01-01

    In prokaryotes and plants the synthesis of the essential amino acids lysine and threonine is predominantly regulated by feed-back inhibition of aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). In order to modify the flux through the aspartate family pathway in barley and enhance the...... as observed in T0 seeds. It is concluded that the aspartate family pathway may be genetically engineered by the introduction of genes coding for feed-back-insensitive enzymes, preferentially giving elevated levels of lysine and methionine.......In prokaryotes and plants the synthesis of the essential amino acids lysine and threonine is predominantly regulated by feed-back inhibition of aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). In order to modify the flux through the aspartate family pathway in barley and enhance...... the accumulation of the corresponding amino acids, we have generated transgenic barley plants that constitutively express mutant Escherichia coli genes encoding lysine feed-back insensitive forms of AK and DHPS. As a result, leaves of primary transformants (T0) exhibited a 14-fold increase of free lysine and an 8...

  19. Site-directed mutagenesis, kinetic and inhibition studies of aspartate ammonia lyase from Bacillus sp YM55-1

    NARCIS (Netherlands)

    Veetil, Vinod Puthan; Raj, Hans; Quax, Wim J.; Janssen, Dick B.; Poelarends, Gerrit J.

    Aspartate ammonia lyases (also referred to as aspartases) catalyze the reversible deamination of l-aspartate to yield fumarate and ammonia. In the proposed mechanism for these enzymes, an active site base abstracts a proton from C3 of l-aspartate to form an enzyme-stabilized enediolate intermediate.

  20. Brain natriutetic peptide test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007509.htm Brain natriuretic peptide test To use the sharing features on this page, please enable JavaScript. Brain natriuretic peptide (BNP) test is a blood test that measures ...

  1. Vasoactive intestinal peptide test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003508.htm Vasoactive intestinal peptide test To use the sharing features on this page, please enable JavaScript. Vasoactive intestinal peptide (VIP) is a test that measures the amount ...

  2. PeptideAtlas

    Data.gov (United States)

    U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

  3. Insulin degludec aspart: One-year real world experience

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available Background: This retrospective analysis describes the use of insulin degludec aspart (IDegAsp in India. Material and Methods: All subjects who had received IDegAsp for 52 weeks at two endocrine centers were included in this study. Results: Forty-eight subjects (40 men, with mean age of 54.33 ± 9.63 years and mean duration of diabetes of 6.33 ± 2.96 years, started IDegAsp as insulin of initiation (16, as an intensification regime (4, as de-escalation from basal-bolus therapy (16, or as switch from premixed insulin (12. The dose of IDegAsp fell from 43.17 ± 21.18 U/day or 0.56 ± 0.23 U/kg to 37.75 ± 17.13U/day (0.51 ± 0.12 U/kg at 24 weeks and 41.41 ± 15.33 U/day (0.56 ± 0.17 U/kg at 52 weeks. Hemoglobin A1c (HbA1c, which was 9.52 ± 1.27% at the start of therapy, fell to 7.51 ± 0.46% at 26 weeks and to 7.48 ± 0.40% at 52 weeks. Fasting plasma glucose fell from 154.08 ± 33.30 mg% to 108.58 ± 22.26 mg% at 26 weeks and 102.17 ± 12.79 mg% at 52 weeks. Of the 48 subjects, 39 (81.25% achieved a target of HbA1c <7.0% at both 26 and 52 weeks. No episode of hypoglycemia was reported in the 4 weeks preceding the analysis. Conclusion: This communication highlights the efficacy, safety, and tolerability, while providing insight into the usage patterns of IDegAsp.

  4. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  5. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  6. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  7. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  8. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  9. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  10. C-Peptide Test

    Science.gov (United States)

    ... Weisenberger, J. (2013 March) Why Does a C-Peptide Test Matter? Diabetes Forecast [On-line information]. Available online at http:// ... Updated). What is c-peptide? What do c-peptide levels mean? Misc.health.diabetes, diabetes FAQ [On-line information from newsgroup]. Available ...

  11. Supporting Aspartate Biosynthesis Is an Essential Function of Respiration in Proliferating Cells.

    Science.gov (United States)

    Sullivan, Lucas B; Gui, Dan Y; Hosios, Aaron M; Bush, Lauren N; Freinkman, Elizaveta; Vander Heiden, Matthew G

    2015-07-30

    Mitochondrial respiration is important for cell proliferation; however, the specific metabolic requirements fulfilled by respiration to support proliferation have not been defined. Here, we show that a major role of respiration in proliferating cells is to provide electron acceptors for aspartate synthesis. This finding is consistent with the observation that cells lacking a functional respiratory chain are auxotrophic for pyruvate, which serves as an exogenous electron acceptor. Further, the pyruvate requirement can be fulfilled with an alternative electron acceptor, alpha-ketobutyrate, which provides cells neither carbon nor ATP. Alpha-ketobutyrate restores proliferation when respiration is inhibited, suggesting that an alternative electron acceptor can substitute for respiration to support proliferation. We find that electron acceptors are limiting for producing aspartate, and supplying aspartate enables proliferation of respiration deficient cells in the absence of exogenous electron acceptors. Together, these data argue a major function of respiration in proliferating cells is to support aspartate synthesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Intersubunit communication in the dihydroorotase–aspartate transcarbamoylase complex of Aquifex aeolicus

    National Research Council Canada - National Science Library

    Evans, Hedeel Guy; Fernando, Roshini; Vaishnav, Asmita; Kotichukkala, Mahalakshmi; Heyl, Deborah; Hachem, Fatme; Brunzelle, Joseph S; Edwards, Brian F.P; Evans, David R

    2014-01-01

    Aspartate transcarbamoylase and dihydroorotase, enzymes that catalyze the second and third step in de novo pyrimidine biosynthesis, are associated in dodecameric complexes in Aquifex aeolicus and many other organisms...

  13. Trapping and structure determination of an intermediate in the allosteric transition of aspartate transcarbamoylase

    National Research Council Canada - National Science Library

    Wenyue Guo; Jay M. West; Andrew S. Dutton; Hiro Tsuruta; Evan R. Kantrowitz

    2012-01-01

    X-ray crystallography and small-angle X-ray scattering (SAXS) in solution have been used to show that a mutant aspartate trans-carbamoylase exists in an intermediate quaternary structure between the canonical T and R structures...

  14. Remifentanil directly activates human N-methyl-D-aspartate receptors expressed in Xenopus laevis oocytes

    NARCIS (Netherlands)

    Hahnenkamp, Klaus; Nollet, Joke; van Aken, Hugo K.; Buerkle, Hartmut; Halene, Tobias; Schauerte, Svenja; Hahnenkamp, Anke; Hollmann, Markus W.; Strümper, Danja; Durieux, Marcel E.; Hoenemann, Christian W.

    2004-01-01

    BACKGROUND: Clinical studies suggest that intraoperative administration of the clinical remifentanil formulation Ultiva (GlaxoWellcome GmbH & Co, Bad Oldesloe, Germany) increases postoperative pain and postoperative analgesic requirements, but mechanisms remain unclear. N-methyl-D-aspartate (NMDA)

  15. Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation

    DEFF Research Database (Denmark)

    Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouther L.J.

    2013-01-01

    . Furthermore, LC–MS (MS) measurements indicated that the combination of aspartate buffer and Zn2+ in particular suppressed intermolecular degradation reactions near the Cys1,6 disulfide bridge. These results lead to the hypothesis that in aspartate buffer, Zn2+ changes the conformation of oxytocin...... in such a way that the Cys1,6 disulfide bridge is shielded from its environment thereby suppressing intermolecular reactions involving this region of the molecule. To verify this hypothesis, we investigate here the conformation of oxytocin in aspartate buffer in the presence of Mg2+ or Zn2+, using 2D NOESY......, with the largest chemical shift changes observed for Cys1. Zn2+ causes more extensive changes in oxytocin in aqueous solution than Mg2+. Our findings suggest that the carboxylate group of aspartate neutralizes the positive charge of the N-terminus of Cys1, allowing the interactions with Zn2+ to become more...

  16. Characterization of peptide immobilization on an acetylene terminated surface via click chemistry

    Science.gov (United States)

    Shamsi, Fahimeh; Coster, Hans; Jolliffe, Katrina A.

    2011-10-01

    Peptide (A-A-A-A-G-G-G-E-R-G-D)1A: Alanine; D: Glutamic acid; E: Aspartic acid; G: Glycine; R: Arginine. conjugated surfaces were prepared on silicon surfaces through click chemistry. The amino acid sequence RGD is the cellular attachment site of a large number of extracellular matrices such as blood and cell surface proteins. Recent research has focused on developing RGD peptides which mimic cell adhesion proteins and integrins [1,2].The steps involved the formation of an alkyne-terminated monolayer on Si(111), followed by linking the peptide to 4-azidophenyl isothiocyanate via a specific and gentle reaction. This was followed by the attachment of the azido peptide to the surface-bound alkynes using the Cu (I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction. The surface structures of the alkyne terminated monolayer and the attached peptide were characterized using high resolution impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared (ATR-FTIR) Spectroscopy. EIS characterization revealed the alkyne layer and the hydrophobic and polar regions of the attached peptide. XPS analysis showed a high surface coverage of the peptide on the silicon substrates and this was confirmed by FTIR.Our results confirmed a specific covalent attachment of the peptide on the silicon surfaces. This approach offers a versatile, experimentally simple, method for the specific attachment of peptide ligands. This approach would have applications for cell attachment and biosensors.

  17. Aspartic peptidases of human pathogenic trypanosomatids: perspectives and trends for chemotherapy.

    Science.gov (United States)

    Santos, L O; Garcia-Gomes, A S; Catanho, M; Sodre, C L; Santos, A L S; Branquinha, M H; d'Avila-Levy, C M

    2013-01-01

    Aspartic peptidases are proteolytic enzymes present in many organisms like vertebrates, plants, fungi, protozoa and in some retroviruses such as human immunodeficiency virus (HIV). These enzymes are involved in important metabolic processes in microorganisms/virus and play major roles in infectious diseases. Although few studies have been performed in order to identify and characterize aspartic peptidase in trypanosomatids, which include the etiologic agents of leishmaniasis, Chagas' disease and sleeping sickness, some beneficial properties of aspartic peptidase inhibitors have been described on fundamental biological events of these pathogenic agents. In this context, aspartic peptidase inhibitors (PIs) used in the current chemotherapy against HIV (e.g., amprenavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir) were able to inhibit the aspartic peptidase activity produced by different species of Leishmania. Moreover, the treatment of Leishmania promastigotes with HIV PIs induced several perturbations on the parasite homeostasis, including loss of the motility and arrest of proliferation/growth. The HIV PIs also induced an increase in the level of reactive oxygen species and the appearance of irreversible morphological alterations, triggering parasite death pathways such as programed cell death (apoptosis) and uncontrolled autophagy. The blockage of physiological parasite events as well as the induction of death pathways culminated in its incapacity to adhere, survive and escape of phagocytic cells. Collectively, these results support the data showing that parasites treated with HIV PIs have a significant reduction in the ability to cause in vivo infection. Similarly, the treatment of Trypanosoma cruzi cells with pepstatin A showed a significant inhibition on both aspartic peptidase activity and growth as well as promoted several and irreversible morphological changes. These studies indicate that aspartic peptidases can be promising targets in

  18. Molecular Mechanisms Elicited by d-Aspartate in Leydig Cells and Spermatogonia

    OpenAIRE

    Maria Maddalena Di Fiore; Alessandra Santillo; Sara Falvo; Salvatore Longobardi; Gabriella Chieffi Baccari

    2016-01-01

    A bulk of evidence suggests that d-aspartate (d-Asp) regulates steroidogenesis and spermatogenesis in vertebrate testes. This review article focuses on intracellular signaling mechanisms elicited by d-Asp possibly via binding to the N-methyl-d-aspartate receptor (NMDAR) in both Leydig cells, and spermatogonia. In Leydig cells, the amino acid upregulates androgen production by eliciting the adenylate cyclase-cAMP and/or mitogen-activated protein kinase (MAPK) pathways. d-Asp treatment enhances...

  19. Motor axon synapses on renshaw cells contain higher levels of aspartate than glutamate.

    Directory of Open Access Journals (Sweden)

    Dannette S Richards

    Full Text Available Motoneuron synapses on spinal cord interneurons known as Renshaw cells activate nicotinic, AMPA and NMDA receptors consistent with co-release of acetylcholine and excitatory amino acids (EAA. However, whether these synapses express vesicular glutamate transporters (VGLUTs capable of accumulating glutamate into synaptic vesicles is controversial. An alternative possibility is that these synapses release other EAAs, like aspartate, not dependent on VGLUTs. To clarify the exact EAA concentrated at motor axon synapses we performed a quantitative postembedding colloidal gold immunoelectron analysis for aspartate and glutamate on motor axon synapses (identified by immunoreactivity to the vesicular acetylcholine transporter; VAChT contacting calbindin-immunoreactive (-IR Renshaw cell dendrites. The results show that 71% to 80% of motor axon synaptic boutons on Renshaw cells contained aspartate immunolabeling two standard deviations above average neuropil labeling. Moreover, VAChT-IR synapses on Renshaw cells contained, on average, aspartate immunolabeling at 2.5 to 2.8 times above the average neuropil level. In contrast, glutamate enrichment was lower; 21% to 44% of VAChT-IR synapses showed glutamate-IR two standard deviations above average neuropil labeling and average glutamate immunogold density was 1.7 to 2.0 times the neuropil level. The results were not influenced by antibody affinities because glutamate antibodies detected glutamate-enriched brain homogenates more efficiently than aspartate antibodies detecting aspartate-enriched brain homogenates. Furthermore, synaptic boutons with ultrastructural features of Type I excitatory synapses were always labeled by glutamate antibodies at higher density than motor axon synapses. We conclude that motor axon synapses co-express aspartate and glutamate, but aspartate is concentrated at higher levels than glutamate.

  20. Engineered isopeptide bond stabilized fibrin inspired nanoscale peptide based sealants for efficient blood clotting

    OpenAIRE

    Ghosh, Snehasish; Mukherjee, Sanchita; Dutta, Chiranjit; Chakraborty, Kasturee; Gayen, Paramita; Jan, Somnath; Bhattacharyya, Dhananjay; Roy, Rituparna Sinha

    2017-01-01

    Designing biologically inspired nanoscale molecular assembly with desired functionality is a challenging endeavour. Here we report the designing of fibrin-inspired nanostructured peptide based sealants which facilitate remarkably fast entrapping of blood corpuscles (~28 seconds) in contrast to fibrin (~56 seconds). Our engineered sealants are stabilized by lysine-aspartate ionic interactions and also by N?(?-glutamyl) lysine isopeptide bond mediated covalent interaction. Each sealant is forme...

  1. Specific binding and mineralization of calcified surfaces by small peptides.

    Science.gov (United States)

    Yarbrough, Daniel K; Hagerman, Elizabeth; Eckert, Randal; He, Jian; Choi, Hyewon; Cao, Nga; Le, Karen; Hedger, Jennifer; Qi, Fengxia; Anderson, Maxwell; Rutherford, Bruce; Wu, Ben; Tetradis, Sotiris; Shi, Wenyuan

    2010-01-01

    Several small (dentin phosphoprotein, one of the major noncollagenous proteins thought to be involved in the mineralization of the dentin extracellular matrix during tooth development. These peptides, consisting of multiple repeats of the tripeptide aspartate-serine-serine (DSS), bind with high affinity to calcium phosphate compounds and, when immobilized, can recruit calcium phosphate to peptide-derivatized polystyrene beads or to demineralized human dentin surfaces. The affinity of binding to hydroxyapatite surfaces increases with the number of (DSS)(n) repeats, and though similar repeated sequences-(NTT)(n), (DTT)(n), (ETT)(n), (NSS)(n), (ESS)(n), (DAA)(n), (ASS)(n), and (NAA)(n)-also showed HA binding activity, it was generally not at the same level as the natural sequence. Binding of the (DSS)(n) peptides to sectioned human teeth was shown to be tissue-specific, with high levels of binding to the mantle dentin, lower levels of binding to the circumpulpal dentin, and little or no binding to healthy enamel. Phosphorylation of the serines of these peptides was found to affect the avidity, but not the affinity, of binding. The potential utility of these peptides in the detection of carious lesions, the delivery of therapeutic compounds to mineralized tissues, and the modulation of remineralization is discussed.

  2. A collagen-targeted biomimetic RGD peptide to promote osteogenesis.

    Science.gov (United States)

    Visser, Rick; Arrabal, Pilar M; Santos-Ruiz, Leonor; Fernandez-Barranco, Raul; Becerra, Jose; Cifuentes, Manuel

    2014-01-01

    Osteogenesis is a complex, multifactorial process in which many different signals interact. The bone morphogenetic proteins (BMPs) are the most potent inducers of osteoblastic differentiation, although very high doses of BMPs in combination with collagen type I formulations have to be used for clinical applications. Although integrin-binding arginine-glycine-aspartic acid (RGD) biomimetic peptides have shown some promising abilities to promote the attachment of cells to biomaterials and to direct their differentiation, the linking of these peptides to collagen sponges usually implies chemical manipulation steps. In this study, we describe the design and characterization of a synthetic collagen-targeted RGD biomimetic (CBD-RGD) peptide formed from a collagen-binding domain derived from the von Willebrand factor and the integrin-binding RGD sequence. This peptide was demonstrated to bind to absorbable collagen type I sponges (ACSs) without performing any chemical linking, and to induce the differentiation of MC3T3-E1 mouse preosteoblasts and rat bone marrow-derived mesenchymal stem cells. Furthermore, in vivo experiments showed that ACSs functionalized with CBD-RGD and loaded with a subfunctional dose of BMP-2-formed ectopic bone in rats, while nonfunctionalized sponges loaded with the same amount of BMP-2 did not. These results indicate that the combination of this biomimetic peptide with the currently used collagen+BMP system might be a promising approach to improve osteogenesis and to reduce the doses of BMPs needed in clinical orthopedics.

  3. Rat d-aspartate oxidase is more similar to the human enzyme than the mouse enzyme.

    Science.gov (United States)

    Katane, Masumi; Kuwabara, Hisashi; Nakayama, Kazuki; Saitoh, Yasuaki; Miyamoto, Tetsuya; Sekine, Masae; Homma, Hiroshi

    2017-12-29

    d-Aspartate oxidase (DDO) is a degradative enzyme that is stereospecific for the acidic amino acid d-aspartate, an endogenous agonist of the N-methyl-d-aspartate (NMDA) receptor. Dysregulation of NMDA receptor-mediated neurotransmission has been implicated in the onset of various neuropsychiatric disorders including schizophrenia, as well as chronic pain. Thus, appropriate regulation of d-aspartate is believed to be important for maintaining proper neural activity in the nervous system. Accordingly, much attention has been paid to the role(s) of DDO in the metabolism of d-aspartate in vivo, and the physiological functions of DDO have been actively investigated using experimental rats and mice. However, detailed characterisation of rat DDO has not yet been performed, and little is known about species-specific differences in the properties of mammalian DDOs. In this study, the structural and enzymatic properties of purified recombinant rat, mouse and human DDOs were examined and compared. The results showed that rat DDO is more similar to human DDO than to mouse DDO. This work provides useful insight into the use of rats as an experimental model for investigating the biological significance of human DDO and/or d-aspartate. This article is part of a Special Issue entitled: d-Amino acids: biology in the mirror, edited by Dr. Loredano Pollegioni, Dr. Jean-Pierre Mothet and Dr. Molla Gianluca. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Lowered circulating aspartate is a metabolic feature of human breast cancer.

    Science.gov (United States)

    Xie, Guoxiang; Zhou, Bingsen; Zhao, Aihua; Qiu, Yunping; Zhao, Xueqing; Garmire, Lana; Shvetsov, Yurii B; Yu, Herbert; Yen, Yun; Jia, Wei

    2015-10-20

    Distinct metabolic transformation is essential for cancer cells to sustain a high rate of proliferation and resist cell death signals. Such a metabolic transformation results in unique cellular metabolic phenotypes that are often reflected by distinct metabolite signatures in tumor tissues as well as circulating blood. Using a metabolomics platform, we find that breast cancer is associated with significantly (p = 6.27E-13) lowered plasma aspartate levels in a training group comprising 35 breast cancer patients and 35 controls. The result was validated with 103 plasma samples and 183 serum samples of two groups of primary breast cancer patients. Such a lowered aspartate level is specific to breast cancer as it has shown 0% sensitivity in serum from gastric (n = 114) and colorectal (n = 101) cancer patients. There was a significantly higher level of aspartate in breast cancer tissues (n = 20) than in adjacent non-tumor tissues, and in MCF-7 breast cancer cell line than in MCF-10A cell lines, suggesting that the depleted level of aspartate in blood of breast cancer patients is due to increased tumor aspartate utilization. Together, these findings suggest that lowed circulating aspartate is a key metabolic feature of human breast cancer.

  5. Molecular cloning and characterization of procirsin, an active aspartic protease precursor from Cirsium vulgare (Asteraceae).

    Science.gov (United States)

    Lufrano, Daniela; Faro, Rosário; Castanheira, Pedro; Parisi, Gustavo; Veríssimo, Paula; Vairo-Cavalli, Sandra; Simões, Isaura; Faro, Carlos

    2012-09-01

    Typical aspartic proteinases from plants of the Astereaceae family like cardosins and cyprosins are well-known milk-clotting enzymes. Their effectiveness in cheesemaking has encouraged several studies on other Astereaceae plant species for identification of new vegetable rennets. Here we report on the cloning, expression and characterization of a novel aspartic proteinase precursor from the flowers of Cirsium vulgare (Savi) Ten. The isolated cDNA encoded a protein product with 509 amino acids, termed cirsin, with the characteristic primary structure organization of plant typical aspartic proteinases. The pro form of cirsin was expressed in Escherichia coli and shown to be active without autocatalytically cleaving its pro domain. This contrasts with the acid-triggered autoactivation by pro-segment removal described for several recombinant plant typical aspartic proteinases. Recombinant procirsin displayed all typical proteolytic features of aspartic proteinases as optimum acidic pH, inhibition by pepstatin, cleavage between hydrophobic amino acids and strict dependence on two catalytic Asp residues for activity. Procirsin also displayed a high specificity towards κ-casein and milk-clotting activity, suggesting it might be an effective vegetable rennet. The findings herein described provide additional evidences for the existence of different structural arrangements among plant typical aspartic proteinases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. A Cooperative Escherichia coli Aspartate Transcarbamoylase without Regulatory Subunits

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, K.; Kantrowitz, E

    2010-01-01

    Here we report the isolation, kinetic characterization, and X-ray structure determination of a cooperative Escherichia coli aspartate transcarbamoylase (ATCase) without regulatory subunits. The native ATCase holoenzyme consists of six catalytic chains organized as two trimers bridged noncovalently by six regulatory chains organized as three dimers, c{sub 6}r{sub 6}. Dissociation of the native holoenzyme produces catalytically active trimers, c{sub 3}, and nucleotide-binding regulatory dimers, r{sub 2}. By introducing specific disulfide bonds linking the catalytic chains from the upper trimer site specifically to their corresponding chains in the lower trimer prior to dissociation, a new catalytic unit, c{sub 6}, was isolated consisting of two catalytic trimers linked by disulfide bonds. Not only does the c{sub 6} species display enhanced enzymatic activity compared to the wild-type enzyme, but the disulfide bonds also impart homotropic cooperativity, never observed in the wild-type c3. The c{sub 6} ATCase was crystallized in the presence of phosphate and its X-ray structure determined to 2.10 {angstrom} resolution. The structure of c{sub 6} ATCase liganded with phosphate exists in a nearly identical conformation as other R-state structures with similar values calculated for the vertical separation and planar angles. The disulfide bonds linking upper and lower catalytic trimers predispose the active site into a more active conformation by locking the 240s loop into the position characteristic of the high-affinity R state. Furthermore, the elimination of the structural constraints imposed by the regulatory subunits within the holoenzyme provides increased flexibility to the c{sub 6} enzyme, enhancing its activity over the wild-type holoenzyme (c{sub 6}r{sub 6}) and c{sub 3}. The covalent linkage between upper and lower catalytic trimers restores homotropic cooperativity so that a binding event at one or so active sites stimulates binding at the other sites. Reduction

  7. A route to anionic hydrophilic films of copolymers of l-leucine, l-aspartic acid and l-aspartic acid esters

    NARCIS (Netherlands)

    Sederel, W.L.; Bantjes, A.; Feijen, Jan

    1975-01-01

    A series of copolymers of l-leucine and β-benzyl-l-aspartate [Leu/Asp(OBz)] covering the range 30–70 mol % of l-leucine, was synthesized by the N-carboxyanhydride (NCA) method. The copolymers were characterized by elemental analysis, infra-red spectroscopy and viscometry. For all compositions high

  8. Differential neuroprotective potential of CRMP2 peptide aptamers conjugated to cationic, hydrophobic, and amphipathic cell penetrating peptides

    Directory of Open Access Journals (Sweden)

    Aubin eMoutal

    2015-01-01

    Full Text Available The microtubule-associated axonal specification collapsin response mediator protein 2 (CRMP2 is a novel target for neuroprotection. A CRMP2 peptide (TAT-CBD3 conjugated to the HIV transactivator of transcription (TAT protein’s cationic cell penetrating peptide motif (CPP protected neurons in the face of toxic levels of Ca2+ influx leaked in via N-methyl-D-aspartate receptor (NMDAR hyperactivation. Here we tested whether replacing the hydrophilic TAT motif with alternative cationic (nona-arginine (R9, hydrophobic (membrane transport sequence (MTS of k-fibroblast growth factor or amphipathic (model amphipathic peptide (MAP CPPs could be superior to the neuroprotection bestowed by TAT-CBD3. In giant plasma membrane vesicles (GPMVs derived from cortical neurons, the peptides translocated across plasma membranes with similar efficiencies. Cortical neurons, acutely treated with peptides prior to a toxic glutamate challenge, demonstrated enhanced efflux of R9-CBD3 compared to others. R9-CBD3 inhibited N-methyl-D-aspartate (NMDA-evoked Ca2+ influx to a similar extent as TAT-CBD3 while MTS-CBD3 was ineffective which correlated with the ability of R9- and TAT-CBD3, but not MTS-CBD3, to block NMDAR interaction with CRMP2. Unrestricted Ca2+ influx through NMDARs leading to delayed calcium dysregulation and neuronal cell death was blocked by all peptides but MAP-CBD3. When applied acutely for 10 minutes, R9-CBD3 was more effective than TAT-CBD3 at neuroprotection while MTS- and MAP-CBD3 were ineffective. In contrast, long-term (> 24 hours treatment with MTS-CBD3 conferred neuroprotection where TAT-CBD3 failed. Neither peptide altered surface trafficking of NMDARs. Neuroprotection conferred by MTS-CBD3 peptide is likely due to its increased uptake coupled with decreased efflux when compared to TAT-CBD3. Overall, our results demonstrate that altering CPPs can bestow differential neuroprotective potential onto the CBD3 cargo.

  9. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Rajasthan cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Akhil Joshi

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Rajasthan, India. Results: A total of 477 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 340, insulin detemir (n = 90, insulin aspart (n = 37, basal insulin plus insulin aspart (n = 7 and other insulin combinations (n = 2. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 8.3% and insulin user (mean HbA 1 c: 8.4% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −0.9%, insulin users: −1.2%. Major hypoglycaemic events decreased from 0.5 events/patient-year to 0.0 events/patient-year in insulin naïve group while no change from baseline (1.3 events/patients-year was observed for insulin users. SADRs were not reported in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  10. Arginine-glycine-aspartic acid-polyethylene glycol-polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture.

    Science.gov (United States)

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine-glycine-aspartic acid (RGD) peptide. Our studies demonstrate that RGD-polyethylene glycol (PEG)-PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT-MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system.

  11. Review of biphasic insulin aspart in the treatment of type 1 and 2 diabetes

    Directory of Open Access Journals (Sweden)

    Nazia Raja-Khan

    2008-01-01

    Full Text Available Nazia Raja-Khan, Sarah S Warehime, Robert A GabbayDivision of Endocrinology, Diabetes, and Metabolism, Penn State Institute for Diabetes and Obesity, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USABackground: Insulin is an effective treatment for achieving glycemic control and preventing complications in patients with diabetes. In order to make insulin therapy more acceptable to patients, newer formulations of insulin have been developed, such as biphasic insulins. Biphasic insulins conveniently provide both prandial and basal insulin in a single injection. One of the most well-studied biphasic insulins is biphasic insulin aspart 70/30.Objective: Our goal was to review the current literature on the safety and efficacy of biphasic insulin aspart in type 1 and type 2 diabetes.Methods: A MEDLINE search was conducted using the terms “biphasic insulin aspart” to identify clinical studies and reviews.Results: Biphasic insulin aspart more effectively reduces post-prandial glucose compared to other biphasic insulins and basal insulins. Compared to biphasic insulin aspart, fasting glucose levels are lower with NPH, similar with glargine, and similar or lower with biphasic human insulin. Treat-to-target trials have shown that a goal HbA1c below 6.5 or 7% can be achieved with biphasic insulin aspart. The risk of hypoglycemia is similar to or less than that seen with other biphasic insulins or NPH insulin.Conclusion: Biphasic insulin aspart 70/30 is a safe and effective treatment option for patients with diabetes.Keywords: biphasic insulin aspart, insulin, diabetes

  12. Modified peptides as potent inhibitors of the postsynaptic density-95/N-methyl-D-aspartate receptor interaction

    DEFF Research Database (Denmark)

    Bach, Anders; Chi, Celestine N.; Olsen, Thomas B.

    2008-01-01

    and unnatural amino acids, which disclosed a tripeptide with micromolar affinity and N-methylated tetrapeptides with improved affinities. Molecular modeling studies guided further N-terminal modifications and introduction of a range of N-terminal substitutions dramatically improved affinity. The best compound......, N-cyclohexylethyl-ETAV (56), demonstrated up to 19-fold lower K i value ( K i = 0.94 and 0.45 microM against PDZ1 and PDZ2 of PSD-95, respectively) compared to wild-type values, providing the most potent inhibitors of this interaction reported so far. These novel and potent inhibitors provide...

  13. Topical peptides as cosmeceuticals

    Directory of Open Access Journals (Sweden)

    Varadraj Vasant Pai

    2017-01-01

    Full Text Available Peptides are known to have diverse biological roles, most prominently as signaling/regulatory molecules in a broad variety of physiological processes including defense, immunity, stress, growth, homeostasis and reproduction. These aspects have been used in the field of dermatology and cosmetology to produce short, stable and synthetic peptides for extracellular matrix synthesis, pigmentation, innate immunity and inflammation. The evolution of peptides over the century, which started with the discovery of penicillin, has now extended to their usage as cosmeceuticals in recent years. Cosmeceutical peptides may act as signal modulators of the extracellular matrix component, as structural peptides, carrier peptides and neurotransmitter function modulators. Transdermal delivery of peptides can be made more effective by penetration enhancers, chemical modification or encapsulation of peptides. The advantages of using peptides as cosmeceuticals include their involvement in many physiological functions of the skin, their selectivity, their lack of immunogenicity and absence of premarket regulatory requirements for their use. However, there are disadvantages: clinical evidence for efficacy is often weak, absorption may be poor due to low lipophilicity, high molecular weight and binding to other ingredients, and prices can be quite high.

  14. Antimicrobial Peptides in Reptiles

    Science.gov (United States)

    van Hoek, Monique L.

    2014-01-01

    Reptiles are among the oldest known amniotes and are highly diverse in their morphology and ecological niches. These animals have an evolutionarily ancient innate-immune system that is of great interest to scientists trying to identify new and useful antimicrobial peptides. Significant work in the last decade in the fields of biochemistry, proteomics and genomics has begun to reveal the complexity of reptilian antimicrobial peptides. Here, the current knowledge about antimicrobial peptides in reptiles is reviewed, with specific examples in each of the four orders: Testudines (turtles and tortosises), Sphenodontia (tuataras), Squamata (snakes and lizards), and Crocodilia (crocodilans). Examples are presented of the major classes of antimicrobial peptides expressed by reptiles including defensins, cathelicidins, liver-expressed peptides (hepcidin and LEAP-2), lysozyme, crotamine, and others. Some of these peptides have been identified and tested for their antibacterial or antiviral activity; others are only predicted as possible genes from genomic sequencing. Bioinformatic analysis of the reptile genomes is presented, revealing many predicted candidate antimicrobial peptides genes across this diverse class. The study of how these ancient creatures use antimicrobial peptides within their innate immune systems may reveal new understandings of our mammalian innate immune system and may also provide new and powerful antimicrobial peptides as scaffolds for potential therapeutic development. PMID:24918867

  15. DFT computational study of the RGD peptide interaction with the rutile TiO2 (110) surface

    Science.gov (United States)

    Muir, J. M. R.; Costa, D.; Idriss, H.

    2014-06-01

    Planewave DFT calculations including ab initio molecular dynamics (AIMD) were used to model the adsorption of a biologically relevant peptide sequence, arginine-glycine-aspartic acid (RGD), upon a rutile TiO2 (110) surface. It was found that binding is solely through the aspartic acid end of the RGD. The carboxy groups bind through dissociative bridging and molecular forms, similar to formic acid. The energy of adsorption is much smaller (0.5-0.77 eV) than seen for formic acid and the molecular adsorption is the strongest adsorption mode. Neutral adsorption is favoured over zwitterionic adsorption and adsorption through the carboxy group of the aspartic acid side chain rather than the terminal carboxy group is favoured due to a configuration allowing an additional surface-carbonyl bond. The RGD backbone is not significantly disrupted upon adsorption.

  16. Biodegradation and Osteosarcoma Cell Cultivation on Poly(aspartic acid) Based Hydrogels.

    Science.gov (United States)

    Juriga, Dávid; Nagy, Krisztina; Jedlovszky-Hajdú, Angéla; Perczel-Kovách, Katalin; Chen, Yong Mei; Varga, Gábor; Zrínyi, Miklós

    2016-09-14

    Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.

  17. Effect of ethylenediamine on chemical degradation of insulin aspart in pharmaceutical solutions.

    Science.gov (United States)

    Poulsen, Christian; Jacobsen, Dorte; Palm, Lisbeth

    2008-11-01

    To examine the effect of different amine compounds on the chemical degradation of insulin aspart at pharmaceutical formulation conditions. Insulin aspart preparations containing amine compounds or phosphate (reference) were prepared and the chemical degradation was assessed following storage at 37 degrees C using chromatographic techniques. Ethylenediamine was examined at multiple concentrations and the resulting insulin-ethylenediamine derivates were structurally characterized using matrix assisted laser desorption ionization time-of-flight mass spectroscopy. The effects on ethylenediamine when omitting glycerol or phenolic compounds from the formulations were investigated. Ethylenediamine was superior in terms of reducing formation of high molecular weight protein and insulin aspart related impurities compared to the other amine compounds and phosphate. Monotransamidation of insulin aspart in the presence of ethylenediamine was observed at all of the six possible Asn/Gln residues with Asn(A21) having the highest propensity to react with ethylenediamine. Data from formulations studies suggests a dual mechanism of ethylenediamine and a mandatory presence of phenolic compounds to obtain the effect. The formation of high molecular weight protein and insulin aspart related impurities was reduced by ethylenediamine in a concentration dependant manner.

  18. Hydroxyproline-induced Helical Disruption in Conantokin Rl-B Affects Subunit-selective Antagonistic Activities toward Ion Channels of N-Methyl-d-aspartate Receptors.

    Science.gov (United States)

    Kunda, Shailaja; Yuan, Yue; Balsara, Rashna D; Zajicek, Jaroslav; Castellino, Francis J

    2015-07-17

    Conantokins are ~20-amino acid peptides present in predatory marine snail venoms that function as allosteric antagonists of ion channels of the N-methyl-d-aspartate receptor (NMDAR). These peptides possess a high percentage of post-/co-translationally modified amino acids, particularly γ-carboxyglutamate (Gla). Appropriately spaced Gla residues allow binding of functional divalent cations, which induces end-to-end α-helices in many conantokins. A smaller number of these peptides additionally contain 4-hydroxyproline (Hyp). Hyp should prevent adoption of the metal ion-induced full α-helix, with unknown functional consequences. To address this disparity, as well as the role of Hyp in conantokins, we have solved the high resolution three-dimensional solution structure of a Gla/Hyp-containing 18-residue conantokin, conRl-B, by high field NMR spectroscopy. We show that Hyp(10) disrupts only a small region of the α-helix of the Mn(2+)·peptide complex, which displays cation-induced α-helices on each terminus of the peptide. The function of conRl-B was examined by measuring its inhibition of NMDA/Gly-mediated current through NMDAR ion channels in mouse cortical neurons. The conRl-B displays high inhibitory selectivity for subclasses of NMDARs that contain the functionally important GluN2B subunit. Replacement of Hyp(10) with N(8)Q results in a Mg(2+)-complexed end-to-end α-helix, accompanied by attenuation of NMDAR inhibitory activity. However, replacement of Hyp(10) with Pro(10) allowed the resulting peptide to retain its inhibitory property but diminished its GluN2B specificity. Thus, these modified amino acids, in specific peptide backbones, play critical roles in their subunit-selective inhibition of NMDAR ion channels, a finding that can be employed to design NMDAR antagonists that function at ion channels of distinct NMDAR subclasses. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Molecular basis for the targeted binding of RGD-containing peptide to integrin αVβ3.

    Science.gov (United States)

    Yu, Yu-Ping; Wang, Qi; Liu, Ying-Chun; Xie, Ying

    2014-02-01

    Integrin αVβ3-targeting peptides with an exposed arginine-glycine-aspartate (RGD) sequence play a crucial role in targeted anticancer drug delivery. The effects of RGD-containing peptide structure and quantity on mechanism of targeted binding of RGD-containing peptide to integrin αVβ3 were studied intensively at the molecular level via molecular dynamic simulations. Targeted recognization was mainly driven by the electrostatic interactions between the residues in RGD and the metal ions in integrin αVβ3, and cyclic arginine-glycine-aspartate-phenylalanine-valine (RGDFV) peptide appeared to be a better vector than the linear RGD-containing peptides. In addition, the optimal molar concentration ratio of RGD peptides to integrin αVβ3 appeared to be 2:1. These results will help improve the current understanding on the mechanism of interactions between RGD and integrin αVβ3, and promote the application prospects of RGD-based vectors in tumor imaging, diagnosis, and cancer therapy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. pH-responsive poly(aspartic acid) hydrogel-coated magnetite nanoparticles for biomedical applications.

    Science.gov (United States)

    Vega-Chacón, Jaime; Arbeláez, María Isabel Amaya; Jorge, Janaina Habib; Marques, Rodrigo Fernando C; Jafelicci, Miguel

    2017-08-01

    A novel multifunctional nanosystem formed by magnetite nanoparticles coated with pH-responsive poly(aspartic acid) hydrogel was developed. Magnetite nanoparticles (Fe3O4) have been intensively investigated for biomedical applications due to their magnetic properties and dimensions similar to the biostructures. Poly(aspartic acid) is a water-soluble, biodegradable and biocompatible polymer, which features makes it a potential candidate for biomedical applications. The nanoparticles surface modification was carried out by crosslinking polysuccinimide on the magnetite nanoparticles surface and hydrolyzing the succinimide units in mild alkaline medium to obtain the magnetic poly(aspartic acid) hydrogel. The surface modification in each step was confirmed by DRIFTS, TEM and zeta potential measurements. The hydrodynamic diameter of the nanosystems decreases as the pH value decreases. The nanosystems showed high colloidal stability in water and no cytotoxicity was detected, which make these nanosystems suitable for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Preparation and properties of poly(aspartic acid)-based hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.D. [Korea Institute of Science and Technology, Seoul (Korea, Republic of); Kim, J.H. [SungKyunKwan University, Suwon (Korea, Republic of); Kim, S.H.; Kim, Y.H. [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    1999-03-01

    High molecular weight polysuccinimide (PSI), as a precursor of poly (aspartic acid), was prepared by thermal polycondensation of L-aspartic acid. The molecular weight was high when phosphoric acid was used as a catalyst, and the ratio to monomer was 0.75 : 1(phosphoric acid : L-aspartic acid). Attempted solution polymerization in various sulfolane/mesitylene mixtures gave only low molecular weight polymers. By the post polymerization of PSI using DCC as a condensing reagent, the molecular weight of PSI could be increased to some extent. Hydrogels was prepared by crosslinking reaction of PSI with diamine, followed by hydrolysis with NaOH either in water or in DMF solution. As high as 104 g water/g-polymer absorption could be obtained from the hydrogel prepared with 3 mol % of hexamethylenediamine. 13 refs., 7 figs., 1 tab.

  2. Differential Aspartate Usage Identifies a Subset of Cancer Cells Particularly Dependent on OGDH.

    Science.gov (United States)

    Allen, Eric L; Ulanet, Danielle B; Pirman, David; Mahoney, Christopher E; Coco, John; Si, Yaguang; Chen, Ying; Huang, Lingling; Ren, Jinmin; Choe, Sung; Clasquin, Michelle F; Artin, Erin; Fan, Zi Peng; Cianchetta, Giovanni; Murtie, Joshua; Dorsch, Marion; Jin, Shengfang; Smolen, Gromoslaw A

    2016-10-11

    Although aberrant metabolism in tumors has been well described, the identification of cancer subsets with particular metabolic vulnerabilities has remained challenging. Here, we conducted an siRNA screen focusing on enzymes involved in the tricarboxylic acid (TCA) cycle and uncovered a striking range of cancer cell dependencies on OGDH, the E1 subunit of the alpha-ketoglutarate dehydrogenase complex. Using an integrative metabolomics approach, we identified differential aspartate utilization, via the malate-aspartate shuttle, as a predictor of whether OGDH is required for proliferation in 3D culture assays and for the growth of xenograft tumors. These findings highlight an anaplerotic role of aspartate and, more broadly, suggest that differential nutrient utilization patterns can identify subsets of cancers with distinct metabolic dependencies for potential pharmacological intervention. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  3. Differential Aspartate Usage Identifies a Subset of Cancer Cells Particularly Dependent on OGDH

    Directory of Open Access Journals (Sweden)

    Eric L. Allen

    2016-10-01

    Full Text Available Although aberrant metabolism in tumors has been well described, the identification of cancer subsets with particular metabolic vulnerabilities has remained challenging. Here, we conducted an siRNA screen focusing on enzymes involved in the tricarboxylic acid (TCA cycle and uncovered a striking range of cancer cell dependencies on OGDH, the E1 subunit of the alpha-ketoglutarate dehydrogenase complex. Using an integrative metabolomics approach, we identified differential aspartate utilization, via the malate-aspartate shuttle, as a predictor of whether OGDH is required for proliferation in 3D culture assays and for the growth of xenograft tumors. These findings highlight an anaplerotic role of aspartate and, more broadly, suggest that differential nutrient utilization patterns can identify subsets of cancers with distinct metabolic dependencies for potential pharmacological intervention.

  4. Onchocerca volvulus: expression and immunolocalization of a nematode cathepsin D-like lysosomal aspartic protease.

    Science.gov (United States)

    Jolodar, Abbas; Fischer, Peter; Büttner, Dietrich W; Miller, David J; Schmetz, Christel; Brattig, Norbert W

    2004-01-01

    The N-terminal region of the cathepsin D-like aspartic protease from the human filarial parasite Onchocerca volvulus was expressed as His-tag fusion protein. Light and electron microscopic immunohistology using antibodies against the recombinant protein showed labeling of lysosomes in the hypodermis and epithelia of the intestine and the reproductive organs of Onchocerca. While developing oocytes were negative, mature oocytes and early morulae showed strong labeling. In older embryos and mature microfilariae, stained lysosomes were only found in a few cells. Cell death in degenerating microfilariae of patients untreated and treated with microfilaricidal drugs was associated with strong expression of aspartic protease. IgG1, IgG4, and IgE antibodies reactive with the recombinant protein were demonstrated in sera from onchocerciasis patients indicating exposure and recognition of the enzyme by the host's defence system. The aspartic protease of O. volvulus appears to function in intestinal digestion and tissue degradation of the filaria.

  5. Blockade of N-methyl-D-aspartate induced convulsions by 1-aminocyclopropanecarboxylates

    Energy Technology Data Exchange (ETDEWEB)

    Skolnick, P.; Marvizon, J.C.G.; Jackson, B.W.; Monn, J.A.; Rice, K.C. (National Institutes of Health, Bethesda, MD (USA)); Lewin, A.H. (Research Triangle Institute, Research Triangle Park, NC (USA))

    1989-01-01

    1-Aminocyclopropanecarboxylic acid is a potent and selective ligand for the glycine modulatory site on the N-methyl-D-aspartate receptor complex. This compound blocks the convulsions and deaths produced by N-methyl-D-aspartate in a dose dependent fashion. In contrast, 1-aminocyclopropanecarboxylic acid does not protect mice against convulsions induced by pentylenetetrazole, strychnine, bicuculline, or maximal electroshock, and does not impair motor performance on either a rotarod or horizontal wire at doses of up to 2 g/kg. The methyl- and ethyl- esters of 1-aminocyclopropanecarboxylic acid are 5- and 2.3-fold more potent, respectively, than the parent compound in blocking the convulsant and lethal effects of N-methyl-D-aspartate. However, these esters are several orders of magnitude less potent than 1-aminocyclopropanecarboxylic acid as inhibitors of strychnine-insensitive ({sup 3}H)glycine binding, indicating that conversion to the parent compound may be required to elicit an anticonvulsant action.

  6. High Temperature During Rice Grain Filling Enhances Aspartate Metabolism in Grains and Results in Accumulation of Aspartate-Family Amino Acids and Protein Components

    Directory of Open Access Journals (Sweden)

    Cheng-gang LIANG

    2013-09-01

    Full Text Available Global warming causes the exacerbation of rice growing environment, which seriously affects rice growth and reproduction, and finally results in the decrease of rice yield and quality. We investigated the activities of aspartate metabolism enzymes in grains, and the contents of Aspartate-family amino acids and protein components to further understand the effects of high temperature (HT on rice nutritional quality during rice grain filling. Under HT, the average activities of aspartate aminotransferase (AAT and aspartokinase (AK in grains significantly increased, the amino acid contents of aspartate (Asp, lysine (Lys, threonine (Thr, methionine (Met and isoleucine (Ile and the protein contents of albumin, globulin, prolamin and glutelin also significantly increased. The results indicated that HT enhanced Asp metabolism during rice grain filling and the enhancement of Asp metabolism might play an important role in the increase of Asp-family amino acids and protein components in grains. In case of the partial appraisal of the change of Asp-family amino acids and protein components under HT, we introduced eight indicators (amino acid or protein content, ratio of amino acid or protein, amino acid or protein content per grain and amino acid or protein content per panicle to estimate the effects of HT. It is suggested that HT during rice grain filling was benefit for the accumulation of Asp-family amino acids and protein components. Combined with the improvement of Asp-family amino acid ratio in grains under HT, it is suggested that HT during grain filling may improve the rice nutritional quality. However, the yields of parts of Asp-family amino acids and protein components were decreased under HT during rice grain filling.

  7. Mutations that cause threonine sensitivity identify catalytic and regulatory regions of the aspartate kinase of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Arévalo-Rodríguez, M; Calderón, I L; Holmberg, S

    1999-01-01

    The HOM3 gene of Saccharomyces cerevisiae encodes aspartate kinase, which catalyses the first step in the branched pathway leading to the synthesis of threonine and methionine from aspartate. Regulation of the carbon flow into this pathway takes place mainly by feedback inhibition of this enzyme...... by threonine. We have isolated and characterized three HOM3 mutants that show growth inhibition by threonine due to a severe, threonine-induced reduction of the carbon flow into the aspartate pathway, leading to methionine limitation. One of the mutants has an aspartate kinase which is 30-fold more strongly...

  8. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Qatar cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Mohamed Hasan Daghash

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Qatar. Results: A total of 91 patients were enrolled in the study. Two insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 88, insulin detemir (n = 2, and other insulin combinations (n = 1. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.9% and insulin users (mean HbA 1 c: 9.1% groups. After 24 weeks of treatment, all the study groups showed improvement in HbA 1 c (insulin naïve: −1.8%, insulin users: −1.3%. Major hypoglycaemia did not occur in the study patients. SADRs were reported in 1.4% of insulin users. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  9. Crystallization and preliminary X-ray diffraction analysis of the periplasmic domain of the Escherichia coli aspartate receptor Tar and its complex with aspartate

    Energy Technology Data Exchange (ETDEWEB)

    Mise, Takeshi; Matsunami, Hideyuki; Samatey, Fadel A.; Maruyama, Ichiro N., E-mail: ichi@oist.jp [Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami, Okinawa 904-0495 (Japan)

    2014-08-27

    The periplasmic domain of the E. coli aspartate receptor Tar was cloned, expressed, purified and crystallized with and without bound ligand. The crystals obtained diffracted to resolutions of 1.58 and 1.95 Å, respectively. The cell-surface receptor Tar mediates bacterial chemotaxis toward an attractant, aspartate (Asp), and away from a repellent, Ni{sup 2+}. To understand the molecular mechanisms underlying the induction of Tar activity by its ligands, the Escherichia coli Tar periplasmic domain with and without bound aspartate (Asp-Tar and apo-Tar, respectively) were each crystallized in two different forms. Using ammonium sulfate as a precipitant, crystals of apo-Tar1 and Asp-Tar1 were grown and diffracted to resolutions of 2.10 and 2.40 Å, respectively. Alternatively, using sodium chloride as a precipitant, crystals of apo-Tar2 and Asp-Tar2 were grown and diffracted to resolutions of 1.95 and 1.58 Å, respectively. Crystals of apo-Tar1 and Asp-Tar1 adopted space group P4{sub 1}2{sub 1}2, while those of apo-Tar2 and Asp-Tar2 adopted space groups P2{sub 1}2{sub 1}2{sub 1} and C2, respectively.

  10. PNA Peptide chimerae

    DEFF Research Database (Denmark)

    Koch, T.; Næsby, M.; Wittung, P.

    1995-01-01

    Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields.......Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....

  11. GROUPS IN PEPTIDE SYNTHESIS

    African Journals Online (AJOL)

    In order to improve the synthesis of peptides with asparagine and glutamine residues, various carboxamide ... protecting groups in solid-phase peptide synthesis (SPPS). This method eliminates all .... to the filtrate, the solution was washed with three 9 mL portions of 5% aqueous citric acid, three 12 mL portions of 5% ...

  12. Multidimensional Design of Anticancer Peptides

    OpenAIRE

    Lin YC; Lim YF; Russo E.; Schneider P; Bolliger L; Edenharter A; Altmann KH; Halin C; Hiss JA; Schneider G

    2015-01-01

    The computer assisted design and optimization of peptides with selective cancer cell killing activity was achieved through merging the features of anticancer peptides cell penetrating peptides and tumor homing peptides. Machine learning classifiers identified candidate peptides that possess the predicted properties. Starting from a template amino acid sequence peptide cytotoxicity against a range of cancer cell lines was systematically optimized while minimizing the effects on primary human e...

  13. Acylation of Therapeutic Peptides

    DEFF Research Database (Denmark)

    Trier, Sofie; Henriksen, Jonas Rosager; Jensen, Simon Bjerregaard

    Oral administration of therapeutic peptides could benefit millions of chronically ill people worldwide, through easier and less stigmatized therapy, and likely improve the long-term effects of currently widespread disease mismanagement. However, oral peptide delivery is a formidable task due......, but it is not widely studied in an oral context. As acylation furthermore increases interactions with the lipid membranes of mammalian cells, it offers several potential benefits for oral delivery of therapeutic peptides, and we hypothesize that tailoring the acylation may be used to optimize intestinal translocation...... to the harsh and selective gastrointestinal system, and development has lacked far behind injection therapy. Peptide acylation is a powerful tool to alter the pharmacokinetics, biophysical properties and chemical stability of injectable peptide drugs, primarily used to prolong blood circulation...

  14. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class...... of antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which...... examples of different peptide QSAR studies, this review highlights some of the missing links and illuminates some of the questions that would be interesting to challenge in a more systematic fashion. Expert opinion: Computer-aided peptide QSAR using molecular descriptors may provide the necessary edge...

  15. Engineered isopeptide bond stabilized fibrin inspired nanoscale peptide based sealants for efficient blood clotting.

    Science.gov (United States)

    Ghosh, Snehasish; Mukherjee, Sanchita; Dutta, Chiranjit; Chakraborty, Kasturee; Gayen, Paramita; Jan, Somnath; Bhattacharyya, Dhananjay; Roy, Rituparna Sinha

    2017-07-26

    Designing biologically inspired nanoscale molecular assembly with desired functionality is a challenging endeavour. Here we report the designing of fibrin-inspired nanostructured peptide based sealants which facilitate remarkably fast entrapping of blood corpuscles (~28 seconds) in contrast to fibrin (~56 seconds). Our engineered sealants are stabilized by lysine-aspartate ionic interactions and also by N(ε)(γ-glutamyl) lysine isopeptide bond mediated covalent interaction. Each sealant is formed by two peptides having complementary charges to promote lysine-aspartate ionic interactions and designed isopeptide bond mediated interactions. Computational analysis reveals the isopeptide bond mediated energetically favourable peptide assemblies in sealants 1-3. Our designed sealants 2 and 3 mimic fibrin-mediated clot formation mechanism in presence of transglutaminase enzyme and blood corpuscles. These fibrin-inspired peptides assemble to form sealants having superior hemostatic activities than fibrin. Designed sealants feature mechanical properties, biocompatibility, biodegradability and high adhesive strength. Such nature-inspired robust sealants might be potentially translated into clinics for facilitating efficient blood clotting to handle traumatic coagulopathy and impaired blood clotting.

  16. Importance of asparagine on the conformational stability and chemical reactivity of selected anti-inflammatory peptides

    Energy Technology Data Exchange (ETDEWEB)

    Soriano-Correa, Catalina, E-mail: csorico@comunidad.unam.mx [Química Computacional, Facultad de Estudios Superiores (FES)-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, C.P. 09230 México, D.F. (Mexico); Barrientos-Salcedo, Carolina [Laboratorio de Química Médica y Quimiogenómica, Facultad de Bioanálisis Campus Veracruz-Boca del Río, Universidad Veracruzana, C.P. 91700 Veracruz (Mexico); Campos-Fernández, Linda; Alvarado-Salazar, Andres [Química Computacional, Facultad de Estudios Superiores (FES)-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, C.P. 09230 México, D.F. (Mexico); Esquivel, Rodolfo O. [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa (UAM-Iztapalapa), C.P. 09340 México, D.F. (Mexico)

    2015-08-18

    Highlights: • Asparagine plays an important role to anti-inflammatory effect of peptides. • The electron-donor substituent groups favor the formation of the hydrogen bonds, which contribute in the structural stability of peptides. • Chemical reactivity and the physicochemical features are crucial in the biological functions of peptides. - Abstract: Inflammatory response events are initiated by a complex series of molecular reactions that generate chemical intermediaries. The structure and properties of peptides and proteins are determined by the charge distribution of their side chains, which play an essential role in its electronic structure and physicochemical properties, hence on its biological functionality. The aim of this study was to analyze the effect of changing one central amino acid, such as substituting asparagine for aspartic acid, from Cys–Asn–Ser in aqueous solution, by assessing the conformational stability, physicochemical properties, chemical reactivity and their relationship with anti-inflammatory activity; employing quantum-chemical descriptors at the M06-2X/6-311+G(d,p) level. Our results suggest that asparagine plays a more critical role than aspartic acid in the structural stability, physicochemical features, and chemical reactivity of these tripeptides. Substituent groups in the side chain cause significant changes on the conformational stability and chemical reactivity, and consequently on their anti-inflammatory activity.

  17. Characterization of the Wild-Type and Truncated Forms of a Neutral GH10 Xylanase from Coprinus cinereus: Roles of C-Terminal Basic Amino Acid-Rich Extension in Its SDS Resistance, Thermostability, and Activity.

    Science.gov (United States)

    Hu, Hang; Chen, Kaixiang; Li, Lulu; Long, Liangkun; Ding, Shaojun

    2017-04-28

    A neutral xylanase (CcXyn) was identified from Coprinus cinereus. It has a single GH10 catalytic domain with a basic amino acid-rich extension (PVRRK) at the C-terminus. In this study, the wild-type (CcXyn) and C-terminus-truncated xylanase (CcXyn-Δ5C) were heterologously expressed in Pichia pastoris and their characteristics were comparatively analyzed with aims to examine the effect of this extension on the enzyme function. The circular dichorism analysis indicated that both enzymes in general had a similar structure, but CcXyn-Δ5C contained less α-helices (42.9%) and more random coil contents (35.5%) than CcXyn (47.0% and 32.8%, respectively). Both enzymes had the same pH (7.0) and temperature (45°C) optima, and similar substrate specificity on different xylans. They all hydrolyzed beechwood xylan primarily to xylobiose and xylotriose. The amounts of xylobiose and xylotriose accounted for 91.5% and 92.2% (w/w) of total xylooligosaccharides (XOS) generated from beechwood by CcXyn and CcXyn-Δ5C, respectively. However, truncation of the C-terminal 5-amino-acids extension significantly improved the thermostability, SDS resistance, and pH stability at pH 6.0-9.0. Furthermore, CcXyn-Δ5C exhibited a much lower Km value than CcXyn (0.27 mg/ml vs 0.83 mg/ml), and therefore, the catalytic efficiency of CcXyn-Δ5C was 2.4-times higher than that of CcXyn. These properties make CcXyn-Δ5C a good model for the structure-function study of (α/β)8-barrel-folded enzymes and a promising candidate for various applications, especially in the detergent industry and XOS production.

  18. A role for D-aspartate oxidase in schizophrenia and in schizophrenia-related symptoms induced by phencyclidine in mice.

    Science.gov (United States)

    Errico, F; D'Argenio, V; Sforazzini, F; Iasevoli, F; Squillace, M; Guerri, G; Napolitano, F; Angrisano, T; Di Maio, A; Keller, S; Vitucci, D; Galbusera, A; Chiariotti, L; Bertolino, A; de Bartolomeis, A; Salvatore, F; Gozzi, A; Usiello, A

    2015-02-17

    Increasing evidence points to a role for dysfunctional glutamate N-methyl-D-aspartate receptor (NMDAR) neurotransmission in schizophrenia. D-aspartate is an atypical amino acid that activates NMDARs through binding to the glutamate site on GluN2 subunits. D-aspartate is present in high amounts in the embryonic brain of mammals and rapidly decreases after birth, due to the activity of the enzyme D-aspartate oxidase (DDO). The agonistic activity exerted by D-aspartate on NMDARs and its neurodevelopmental occurrence make this D-amino acid a potential mediator for some of the NMDAR-related alterations observed in schizophrenia. Consistently, substantial reductions of D-aspartate and NMDA were recently observed in the postmortem prefrontal cortex of schizophrenic patients. Here we show that DDO mRNA expression is increased in prefrontal samples of schizophrenic patients, thus suggesting a plausible molecular event responsible for the D-aspartate imbalance previously described. To investigate whether altered D-aspartate levels can modulate schizophrenia-relevant circuits and behaviors, we also measured the psychotomimetic effects produced by the NMDAR antagonist, phencyclidine, in Ddo knockout mice (Ddo(-)(/-)), an animal model characterized by tonically increased D-aspartate levels since perinatal life. We show that Ddo(-/-) mice display a significant reduction in motor hyperactivity and prepulse inhibition deficit induced by phencyclidine, compared with controls. Furthermore, we reveal that increased levels of D-aspartate in Ddo(-/-) animals can significantly inhibit functional circuits activated by phencyclidine, and affect the development of cortico-hippocampal connectivity networks potentially involved in schizophrenia. Collectively, the present results suggest that altered D-aspartate levels can influence neurodevelopmental brain processes relevant to schizophrenia.

  19. Persistent elevation of D-Aspartate enhances NMDA receptor-mediated responses in mouse substantia nigra pars compacta dopamine neurons.

    Science.gov (United States)

    Krashia, Paraskevi; Ledonne, Ada; Nobili, Annalisa; Cordella, Alberto; Errico, Francesco; Usiello, Alessandro; D'Amelio, Marcello; Mercuri, Nicola Biagio; Guatteo, Ezia; Carunchio, Irene

    2016-04-01

    Dopamine neurons in the substantia nigra pars compacta regulate not only motor but also cognitive functions. NMDA receptors play a crucial role in modulating the activity of these cells. Considering that the amino-acid D-Aspartate has been recently shown to be an endogenous NMDA receptor agonist, the aim of the present study was to examine the effects of D-Aspartate on the functional properties of nigral dopamine neurons. We compared the electrophysiological actions of D-Aspartate in control and D-aspartate oxidase gene (Ddo(-/-)) knock-out mice that show a concomitant increase in brain D-Aspartate levels, improved synaptic plasticity and cognition. Finally, we analyzed the effects of L-Aspartate, a known dopamine neuron endogenous agonist in control and Ddo(-/-) mice. We show that D- and L-Aspartate excite dopamine neurons by activating NMDA, AMPA and metabotropic glutamate receptors. Ddo deletion did not alter the intrinsic properties or dopamine sensitivity of dopamine neurons. However, NMDA-induced currents were enhanced and membrane levels of the NMDA receptor GluN1 and GluN2A subunits were increased. Inhibition of excitatory amino-acid transporters caused a marked potentiation of D-Aspartate, but not L-Aspartate currents, in Ddo(-/-) neurons. This is the first study to show the actions of D-Aspartate on midbrain dopamine neurons, activating not only NMDA but also non-NMDA receptors. Our data suggest that dopamine neurons, under conditions of high D-Aspartate levels, build a protective uptake mechanism to compensate for increased NMDA receptor numbers and cell hyper-excitation, which could prevent the consequent hyper-dopaminergia in target zones that can lead to neuronal degeneration, motor and cognitive alterations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. The role of N-methyl-D-aspartate receptors and nitric oxide in cochlear dopamine release

    NARCIS (Netherlands)

    Halmos, Gyorgy; Horvath, T.; Polony, G.; Fekete, A.; Kittel, A.; Vizi, E. S.; van der Laan, B. F. A. M.; Zelles, T.; Lendvai, B.

    2008-01-01

    Dopamine (DA) released from lateral olivocochlear (LOC) terminals may have a neuroprotective effect in the cochlea. To explore the role of N-methyl-D-aspartate (NMDA) receptors and nitric oxide (NO) in the modulation of a cochlear DA release, we measured the release of [(3)H]DA from isolated mouse

  1. Regulation of aspartate-derived amino-acid metabolism in Zygosaccharomyces rouxii compared to Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Sluis, van der C.; Smit, B.A.; Hartmans, S.; Schure, ter E.G.; Tramper, J.; Wijffels, R.H.

    2000-01-01

    To elucidate the growth inhibitory effect of threonine, the regulation of the aspartate-derived amino-acid metabolism in Zygosaccharomyces rouxii, an important yeast for the flavor development in soy sauce, was investigated. It was shown that threonine inhibited the growth of Z. rouxii by blocking

  2. Tweaking agonist efficacy at N-methyl-D-aspartate receptors by site-directed mutagenesis

    DEFF Research Database (Denmark)

    Hansen, Kasper B; Clausen, Rasmus P; Bjerrum, Esben J

    2005-01-01

    The structural basis for partial agonism at N-methyl-D-aspartate (NMDA) receptors is currently unresolved. We have characterized several partial agonists at the NR1/NR2B receptor and investigated the mechanisms underlying their reduced efficacy by introducing mutations in the glutamate binding si...

  3. Discovery of MK-8718, an HIV Protease Inhibitor Containing a Novel Morpholine Aspartate Binding Group.

    Science.gov (United States)

    Bungard, Christopher J; Williams, Peter D; Ballard, Jeanine E; Bennett, David J; Beaulieu, Christian; Bahnck-Teets, Carolyn; Carroll, Steve S; Chang, Ronald K; Dubost, David C; Fay, John F; Diamond, Tracy L; Greshock, Thomas J; Hao, Li; Holloway, M Katharine; Felock, Peter J; Gesell, Jennifer J; Su, Hua-Poo; Manikowski, Jesse J; McKay, Daniel J; Miller, Mike; Min, Xu; Molinaro, Carmela; Moradei, Oscar M; Nantermet, Philippe G; Nadeau, Christian; Sanchez, Rosa I; Satyanarayana, Tummanapalli; Shipe, William D; Singh, Sanjay K; Truong, Vouy Linh; Vijayasaradhi, Sivalenka; Wiscount, Catherine M; Vacca, Joseph P; Crane, Sheldon N; McCauley, John A

    2016-07-14

    A novel HIV protease inhibitor was designed using a morpholine core as the aspartate binding group. Analysis of the crystal structure of the initial lead bound to HIV protease enabled optimization of enzyme potency and antiviral activity. This afforded a series of potent orally bioavailable inhibitors of which MK-8718 was identified as a compound with a favorable overall profile.

  4. Utilization of L-aspartate, L-malate and fumarate by Pasteurella multocida

    Energy Technology Data Exchange (ETDEWEB)

    Hoefer, M.; Flossmann, K.D. (Akademie der Landwirtschaftswissenschaften der DDR, Jena. Inst. fuer Bakterielle Tierseuchenforschung)

    1981-01-01

    Strains of Pasteurella multocida use L-aspartate, L-malate and furmarate, respectively, as substrates for production of succinic acid which accumulates in the medium. As was established by studies with /sup 14/C- and /sup 3/H-labelled substrates, the degradation of these substances proceeds analogously via the citric acid cycle.

  5. Preparation and evaluation of glycosylated arginine-glycine-aspartate (RGD) derivatives for integrin targeting.

    NARCIS (Netherlands)

    Kuijpers, B.H.M.; Groothuys, S.; Soede, A.C.; Laverman, P.; Boerman, O.C.; Delft, F.L. van; Rutjes, F.P.J.T.

    2007-01-01

    Arginine-glycine-aspartate (RGD) derivatives were prepared by a combination of solid-phase and solution-phase synthesis for selective targeting of alpha vbeta 3 integrin expressed in tumors. In order to evaluate the value of a triazole moiety as a proposed amide isostere, the side chain glycosylated

  6. Neurone-specific enolase and N-acetyl-aspartate as potential peripheral markers of ischaemic stroke

    NARCIS (Netherlands)

    Stevens, H; Jakobs, C; de Jager, AEJ; Cunningham, RT; Korf, J

    Background After stroke, brain-specific proteins (including neurone-specific enolase) leak into the blood. The question addressed in the present study was whether N-acetyl-aspartate (amino acid derivative localized in cerebral neurones) could also serve as a peripheral marker of ischaemic damage.

  7. SPECIATION OF L-ASPARTIC ACID COMPLEXES OF Co(II), Ni(II ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Chemical speciation of binary complexes of Co(II), Ni(II), Cu(II) and Zn(II) with L-aspartic acid was investigated pH-metrically in acetonitrile- and ethylene glycol-water mixtures. The stability constants were calculated using the computer program MINIQUAD75. The best-fit chemical models were selected based ...

  8. Kinetics of reactions of aquacobalamin with aspartic and glutamic acids and their amides in water solutions

    Science.gov (United States)

    Bui, T. T. T.; Sal'nikov, D. S.; Dereven'kov, I. A.; Makarov, S. V.

    2017-04-01

    The kinetics of aquacobalamin reaction with aspartic and glutamic acids, and with their amides in water solutions, is studied via spectrophotometry. The kinetic and activation parameters of the process are determined. It is shown that the reaction product is cobalamin-amino acid complex. The data are compared to results on the reaction between aquacobalamin and primary amines.

  9. Hypoglycemia in type 1 diabetic pregnancy: role of preconception insulin aspart treatment in a randomized study

    DEFF Research Database (Denmark)

    Heller, Simon; Damm, Peter; Mersebach, Henriette

    2010-01-01

    OBJECTIVE A recent randomized trial compared prandial insulin aspart (IAsp) with human insulin in type 1 diabetic pregnancy. The aim of this exploratory analysis was to investigate the incidence of severe hypoglycemia during pregnancy and compare women enrolled preconception with women enrolled...

  10. N-methyl-D-aspartate promotes the survival of cerebellar granule cells: pharmacological characterization

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1989-01-01

    The survival of cerebellar granule cells in culture is promoted by chronic exposure to N-methyl-D-aspartate (NMDA). The effect is due to the stimulation of 'conventional' NMDA receptor-ionophore complex: it is concentration dependent, voltage dependent and blocked by the selective antagonists D-2...

  11. An aspartic proteinase gene family in the filamentous fungus Botrytis cinerea contains members with novel features

    NARCIS (Netherlands)

    Have, ten A.; Dekkers, E.; Kay, J.; Phylip, L.H.; Kan, van J.A.L.

    2004-01-01

    Botrytis cinerea, an important fungal plant pathogen, secretes aspartic proteinase (AP) activity in axenic cultures. No cysteine, serine or metalloproteinase activity could be detected. Proteinase activity was higher in culture medium containing BSA or wheat germ extract, as compared to minimal

  12. Discovery of MK-8718, an HIV Protease Inhibitor Containing a Novel Morpholine Aspartate Binding Group

    Energy Technology Data Exchange (ETDEWEB)

    Bungard, Christopher J.; Williams, Peter D.; Ballard, Jeanine E.; Bennett, David J.; Beaulieu, Christian; Bahnck-Teets, Carolyn; Carroll, Steve S.; Chang, Ronald K.; Dubost, David C.; Fay, John F.; Diamond, Tracy L.; Greshock, Thomas J.; Hao, Li; Holloway, M. Katharine; Felock, Peter J.; Gesell, Jennifer J.; Su, Hua-Poo; Manikowski, Jesse J.; McKay, Daniel J.; Miller, Mike; Min, Xu; Molinaro, Carmela; Moradei, Oscar M.; Nantermet, Philippe G.; Nadeau, Christian; Sanchez, Rosa I.; Satyanarayana, Tummanapalli; Shipe, William D.; Singh, Sanjay K.; Truong, Vouy Linh; Vijayasaradhi, Sivalenka; Wiscount, Catherine M.; Vacca, Joseph P.; Crane, Sheldon N.; McCauley, John A. (Merck); (Albany MR)

    2016-07-14

    A novel HIV protease inhibitor was designed using a morpholine core as the aspartate binding group. Analysis of the crystal structure of the initial lead bound to HIV protease enabled optimization of enzyme potency and antiviral activity. This afforded a series of potent orally bioavailable inhibitors of which MK-8718 was identified as a compound with a favorable overall profile.

  13. An Essential Role of the Mitochondrial Electron Transport Chain in Cell Proliferation Is to Enable Aspartate Synthesis.

    Science.gov (United States)

    Birsoy, Kıvanç; Wang, Tim; Chen, Walter W; Freinkman, Elizaveta; Abu-Remaileh, Monther; Sabatini, David M

    2015-07-30

    The mitochondrial electron transport chain (ETC) enables many metabolic processes, but why its inhibition suppresses cell proliferation is unclear. It is also not well understood why pyruvate supplementation allows cells lacking ETC function to proliferate. We used a CRISPR-based genetic screen to identify genes whose loss sensitizes human cells to phenformin, a complex I inhibitor. The screen yielded GOT1, the cytosolic aspartate aminotransferase, loss of which kills cells upon ETC inhibition. GOT1 normally consumes aspartate to transfer electrons into mitochondria, but, upon ETC inhibition, it reverses to generate aspartate in the cytosol, which partially compensates for the loss of mitochondrial aspartate synthesis. Pyruvate stimulates aspartate synthesis in a GOT1-dependent fashion, which is required for pyruvate to rescue proliferation of cells with ETC dysfunction. Aspartate supplementation or overexpression of an aspartate transporter allows cells without ETC activity to proliferate. Thus, enabling aspartate synthesis is an essential role of the ETC in cell proliferation. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. A randomized trial of insulin aspart with intensified basal NPH insulin supplementation in people with Type 1 diabetes

    NARCIS (Netherlands)

    DeVries, J. H.; Lindholm, A.; Jacobsen, J. L.; Heine, R. J.; Home, P. D.

    2003-01-01

    Aims Insulin aspart has been shown to improve post-prandial and overall glycaemic control in people with Type 1 diabetes. We hypothesized that insulin aspart with intensified basal NPH insulin supplementation would result in better overall glycaemic control than human regular insulin with standard

  15. A study on the applicability of L-aspartate alpha-decarboxylase in the biobased production of nitrogen containing chemicals

    NARCIS (Netherlands)

    Könst, P.M.; Franssen, M.C.R.; Scott, E.L.; Sanders, J.P.M.

    2009-01-01

    -Alanine could serve as an intermediate in the biobased production of nitrogen containing chemicals from L-aspartic acid. Following the biorefinery concept, L-aspartic acid could become widely available from biomass waste streams via the nitrogen storage polypeptide cyanophycin. Since

  16. Prevention of filtering surgery failure by subconjunctival injection of a novel peptide hydrogel into rabbit eyes

    Energy Technology Data Exchange (ETDEWEB)

    Liang Liang [Department of Ophthalmology, The Central Hospital of Wuhan, Wuhan 430014 (China); Xu Xiaoding; Zhang Xianzheng [Key Laboratory of Biomedical Polymers of Ministry of Education and Department of Chemistry, Wuhan University, Wuhan 430072 (China); Feng Mei; Peng Chong; Jiang Fagang [Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2010-08-01

    A novel biocompatible hydrogel was prepared based on the supramolecular self-assembly of a peptide containing a bioactive RGD (arginine-glycine-aspartic acid) sequence and a hydrophobic N-fluorenyl-9-methoxycarbonyl (FMOC) tail. When the self-assembled peptide hydrogel was administered after the filtering surgery of rabbit eyes, the level of connective tissue growth factor (CTGF) mRNA as well as the mean intraocular pressure (IOP) was significantly lower than that of the control eyes during the 21 postoperative days. The filtration bleb and ultrasound biomicroscopy (UBM) images showed that a patent bleb and a filtration fistula could be found in the surgical site of a rabbit eye during the whole experimental period. Histological analysis further evidenced that the filtering surgical wound healing was a normal healing process without scar formation. This new approach, making use of a self-assembled peptide hydrogel to normalize filtering surgical wound healing, may have potential for glaucoma filtering surgery.

  17. Is aspartate 52 essential for catalysis by chicken egg white lysozyme? The role of natural substrate-assisted hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Ichiro; Kirsch, J.F. [Univ. of California, Berkeley, CA (United States)

    1996-02-13

    The chicken and goose egg white lysozymes (ChEWL and GoEWL) are homologues, but differ in substrate specificity. ChEWL catalyzes the hydrolysis of the glycosidic bonds of bacterial peptidoglycans and chitin-derived substrates, while GoEWL is specific for bacterial peptidoglycans. The active-site aspartate 52 residue of ChEWL, which is postulated to stabilize the oxocarbenium ion intermediate, has no counterpart in GoEWL. The substrate specificity of the D52A ChEWL mutant was compared with those of wild-type ChEWL and GoEWL. D52A ChEWL retains approximately 4% of the wild-type catalytic activity in reactions with three different bacterial cell suspensions. Asp52 therefore is not essential to the catalytic mechanism, accounting for only a 2 kcal/mol decrease in AG. The function of Asp52 in D52A ChEWL- and GoEWL-catalyzed cleavage of (carboxymethyl)chitin may be partially fulfilled by an appropriately positioned carboxyl group on the substrate (substrate-assisted catalysis). D52A ChEWL and GoEWL, unlike wild-type ChEWL, exhibit biphasic kinetics in the clearing of Micrococcus luteus cell suspensions, suggesting preferences for subsets of the linkages in the M. luteus peptidoglycan. These subsets do not exist in the peptidoglycans of Escherichia coli or Sarcina lutea, since neither D52A ChEWL nor GoEWL exhibits initial bursts in reactions with suspensions of these bacteria. We propose that substrate-assisted catalysis occurs in reactions of D52A ChEWL and GoEWL with M. luteus peptidoglycans, with the glycine carboxyl group of uncross-linked peptides attached to N-acetylmuramic acid partially substituting the function of the missing Asp52. 52 refs., 6 figs., 1 tab.

  18. Protective actions of des-aspartate-angiotensin I in mice model of CEES-induced lung intoxication.

    Science.gov (United States)

    Ng, Eugene Teck-Leong; Sim, Meng-Kwoon; Loke, Weng-Keong

    2011-08-01

    The present study investigated the protective actions of des-aspartate-angiotensin I (DAA-I) in mice that were intranasally administered 2-chloroethyl ethyl sulfide (CEES), a half sulfur mustard. The protection was dose-dependent, and an oral dose of 75 mg kg⁻¹ per day administered 18 h post exposure and for the following 13 days, offered maximum protection that increased survival by a third. DAA-I attenuated the early processes of inflammation seen in the CEES-inoculated mice. DAA-I attenuated (i) elevated pulmonary ROS, and gp91-phox protein of NADPH oxidase, a non phagocytic enzyme that generates superoxide and subsequent ROS; (ii) intercellular adhesion molecule-1 (ICAM⁻¹) that is involved in the extravasation of circulating leucocytes; and (iii) myeloperoxidase activity, which is a surrogate enzymatic measurement of neutrophil infiltration. These actions led to improved histological lung structures, and survival of type-1 pneumocytes. The action of DAA-I on animal survival was blocked by losartan, a selective angiotensin AT1 receptor blocker, indicting that the AT1 receptor mediates the protection. The presence of elevated PGE2 and PGI2 in lung supernatants of DAA-I treated CEES-inoculated mice indicates that the two prostaglandins are involved in signaling the protective actions of DAA-I. This finding complements earlier studies showing that DAA-I acts on an indomethacin-sensitive angiotensin AT1 receptor. The findings of the present study are the first demonstration of an angiotensin peptide as an effective antidote for CEES intoxication. DAA-I is also an effective therapeutic intervention against CEES that was instituted at 18 h post exposure, and challenges conventional assumptions of limited efficacy with delayed action against alkylating agents. Copyright © 2010 John Wiley & Sons, Ltd.

  19. The role of phosphorylation in dentin phosphoprotein peptide absorption to hydroxyapatite surfaces: a molecular dynamics study.

    Science.gov (United States)

    Villarreal-Ramirez, Eduardo; Garduño-Juarez, Ramón; Gericke, Arne; Boskey, Adele

    2014-08-01

    Dentin phosphoprotein (DPP) is a protein expressed mainly in dentin and to a lesser extent in bone. DPP has a disordered structure, rich in glutamic acid, aspartic acid and phosphorylated serine/threonine residues. It has a high capacity for binding to calcium ions and to hydroxyapatite (HA) crystal surfaces. We used molecular dynamics (MD) simulations as a method for virtually screening interactions between DPP motifs and HA. The goal was to determine which motifs are absorbed to HA surfaces. For these simulations, we considered five peptides from the human DPP sequence. All-atom MD simulations were performed using GROMACS, the peptides were oriented parallel to the {100} HA crystal surface, the distance between the HA and the peptide was 3 nm. The system was simulated for 20 ns. Preliminary results show that for the unphosphorylated peptides, the acidic amino acids present an electrostatic attraction where their side chains are oriented towards HA. This attraction, however, is slow to facilitate bulk transport to the crystal surface. On the other hand, the phosphorylated (PP) peptides are rapidly absorbed on the surface of the HA with their centers of mass closer to the HA surface. More importantly, the root mean square fluctuation (RMSF) indicates that the average structures of the phosphorylated peptides are very inflexible and elongate, while that of the unphosphorylated peptides are flexible. Radius of gyration (Rg) analysis showed the compactness of un-phosphorylated peptides is lower than phosphorylated peptides. Phosphorylation of the DPP peptides is necessary for binding to HA surfaces.

  20. Insulin C-peptide

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003701.htm Insulin C-peptide test To use the sharing features ... a product that is created when the hormone insulin is produced and released into the body. The ...

  1. Tumor penetrating peptides

    Directory of Open Access Journals (Sweden)

    Tambet eTeesalu

    2013-08-01

    Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular zip code of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is

  2. Innovative Therapeutics: Designer Natriuretic Peptides.

    Science.gov (United States)

    Meems, Laura M G; Burnett, John C

    2016-12-01

    Endogenous natriuretic peptides serve as potent activators of particulate guanylyl cyclase receptors and the second messenger cGMP. Natriuretic peptides are essential in maintenance of volume homeostasis, and can be of myocardial, renal and endothelial origin. Advances in peptide engineering have permitted the ability to pursue highly innovative drug discovery strategies. This has resulted in designer natriuretic peptides that go beyond native peptides in efficacy, specificity, and resistance to enzymatic degradation. Together with recent improvements in peptide delivery systems, which have improved bioavailability, further advances in this field have been made. Therefore, designer natriuretic peptides with pleotropic actions together with strategies of chronic delivery have provided an unparalleled opportunity for the treatment of cardiovascular disease. In this review, we report the conceptual framework of peptide engineering of the natriuretic peptides that resulted in designer peptides for cardiovascular disease. We specifically provide an update on those currently in clinical trials for heart failure and hypertension, which include Cenderitide, ANX042 and ZD100.

  3. Cooperative binding of the bisubstrate analog N-(phosphonacetyl)-L-aspartate to aspartate transcarbamoylase and the heterotropic effects of ATP and CTP

    Energy Technology Data Exchange (ETDEWEB)

    Newell, J.O.; Markby, D.W.; Schachman, H.K.

    1989-02-15

    Most investigations of the allosteric properties of the regulatory enzyme aspartate transcarbamoylase (ATCase) from Escherichia coli are based on the sigmoidal dependence of enzyme activity on substrate concentration and the effects of the inhibitor, CTP, and the activator, ATP, on the saturation curves. Interpretations of these effects in terms of molecular models are complicated by the inability to distinguish between changes in substrate binding and catalytic turnover accompanying the allosteric transition. In an effort to eliminate this ambiguity, the binding of the 3H-labeled bisubstrate analog N-(phosphonacetyl)-L-aspartate (PALA) to aspartate transcarbamoylase in the absence and presence of the allosteric effectors ATP and CTP has been measured directly by equilibrium dialysis at pH 7 in phosphate buffer. PALA binds with marked cooperativity to the holoenzyme with an average dissociation constant of 110 nM. ATP and CTP alter both the average affinity of ATCase for PALA and the degree of cooperativity in the binding process in a manner analogous to their effects on the kinetic properties of the enzyme; the average dissociation constant of PALA decreases to 65 nM in the presence of ATP and increases to 266 nM in the presence of CTP while the Hill coefficient, which is 1.95 in the absence of effectors, becomes 1.35 and 2.27 in the presence of ATP and CTP, respectively. The dissociation constant of PALA from the catalytic subunit is 95 nM. Interpretation of these results in terms of a thermodynamic scheme linking PALA binding to the assembly of ATCase from catalytic and regulatory subunits demonstrates that saturation of the enzyme with PALA shifts the equilibrium between holoenzyme and subunits slightly toward dissociation.

  4. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...... a group consisting of naturally-occurring nucleobases and non-naturally-occurring nucleobases, including 2,6-diaminopurine, attached to a polyamide backbone, and contain alkyl amine side chains....

  5. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    peptides has only been elucidated during the last decade. The cellular synthesis including amino acid modifications and proteolytic cleavages has proven considerably more complex than initially perceived. Consequently, the elimination phase of the peptide products in circulation is not yet well...... competent endocrine cells. The structurally related atrial natriuretic peptide will be mentioned where appropriate, whereas C-type natriuretic peptide will not be considered as a cardiac peptide of relevance in mammalian physiology....

  6. Recombinant production of the therapeutic peptide lunasin

    Directory of Open Access Journals (Sweden)

    Kyle Stuart

    2012-02-01

    Full Text Available Abstract Background Lunasin is a chemopreventive peptide produced in a number of plant species. It comprises a helical region with homology to a region of chromatin binding proteins, an Arg-Gly-Asp cell adhesion motif and eight aspartic acid residues. In vitro studies indicate that lunasin suppresses chemical and oncogene driven transformation of mammalian cells. We have explored efficient recombinant production of lunasin by exploiting the Clostridium thermocellum CipB cellulose binding domain (CBD as a fusion partner protein. Results We used a pET28 vector to express a CBD-lunasin fusion with a hexahistidine tag and Tobacco Etch Virus protease site, to allow protease-mediated release of native lunasin. Autoinduction in E. coli BL21 (DE3 Star cells achieved expression of 3.35 g/L of CBD-lunasin fusion protein. The final yield of lunasin was 210 mg/L corresponding to 32% of the theoretical yield. Purification by cellulose binding and nickel affinity chromatography were tested with the latter proving more satisfactory. The effects of CBD-lunasin expression on growth and morphology of the E. coli cells were examined by light and electron microscopy revealing an altered morphology in a proportion of cells. Cell division appeared to be inhibited in these cells resulting in elongated, non-septated cells. Conclusions The use of CBD as a fusion partner gave high protein yields by autoinduction, with lunasin release by TEV protease cleavage. With some optimisation this approach could provide a potentially valuable route for production of this therapeutic peptide. Over-expression in the host cells manifest as a cell division defect in a population of the cells, presumably mimicking some aspect of the chemopreventive function observed in mammalian cells.

  7. Natriuretic Peptides, Diagnostic and Prognostic Biomarkers

    NARCIS (Netherlands)

    J.H.W. Rutten (Joost)

    2010-01-01

    textabstractIn humans, the natriuretic peptide family consists of three different types of peptides: atrial natriuretic peptide (synonym: atrial natriuretic factor), B-type natriuretic peptide (synonym: brain natriuretic peptide) and C-natriuretic peptide.1 Atrial natriuretic peptide (ANP) was

  8. Bioimprinted Polymer Scaffolds for Selective Recognition of RGD Peptides

    Science.gov (United States)

    Bergmann, Nicole; Peppas, Nicholas A.

    2003-03-01

    Fibronectin and a number of other plasma and extracellular matrix (ECM) adhesion proteins contain the tetrapeptide arginine-glycine-aspartic acid-serine (RGDS), and this sequence can be summarily recognized and bound by integrins present on cell membranes. Upon integrin binding, cells adhere to the substrate, and this adherence encourages ECM deposition and other cellular remodeling events. By targeting specific chemical functional groups on the peptide using non-covalent molecular imprinting, biomimetic polymeric scaffolds can be designed to mimic protein-ECM binding both on the surface and in the bulk during polymer degradation. Methacrylic acid-ethylene glycol dimethacrylate (MAA-g-EGDMA) copolymer films were prepared by free-radical ultraviolet polymerization in the presence of RGDS to create novel imprinted matrices for possible tissue engineering scaffolds. SEM analysis revealed a highly macroporous structure in peptide-imprinted polymers compared to controls. Optimal crosslinking ratios for peptide imprinting were determined using a small molecular weight fluorescent tag, 4-chloro-7-nitrobenzofurazan, and analyzed using fluorescent microscopy. Higher crosslinking ratios yielded better template recognition and gels exhibited specific recognition in aqueous media to RGDS molecules when in the presence of similar tetrapeptides.

  9. Natriuretic Peptides, Diagnostic and Prognostic Biomarkers

    OpenAIRE

    Rutten, Joost

    2010-01-01

    textabstractIn humans, the natriuretic peptide family consists of three different types of peptides: atrial natriuretic peptide (synonym: atrial natriuretic factor), B-type natriuretic peptide (synonym: brain natriuretic peptide) and C-natriuretic peptide.1 Atrial natriuretic peptide (ANP) was the fi rst natriuretic peptide to be discovered and in humans ANP is predominantly formed in the cardiomyocytes of the atria.2 B-type natriuretic peptide (BNP) was fi rst discovered in porcine brain hen...

  10. Granin-derived peptides.

    Science.gov (United States)

    Troger, Josef; Theurl, Markus; Kirchmair, Rudolf; Pasqua, Teresa; Tota, Bruno; Angelone, Tommaso; Cerra, Maria C; Nowosielski, Yvonne; Mätzler, Raphaela; Troger, Jasmin; Gayen, Jaur R; Trudeau, Vance; Corti, Angelo; Helle, Karen B

    2017-07-01

    The granin family comprises altogether 7 different proteins originating from the diffuse neuroendocrine system and elements of the central and peripheral nervous systems. The family is dominated by three uniquely acidic members, namely chromogranin A (CgA), chromogranin B (CgB) and secretogranin II (SgII). Since the late 1980s it has become evident that these proteins are proteolytically processed, intragranularly and/or extracellularly into a range of biologically active peptides; a number of them with regulatory properties of physiological and/or pathophysiological significance. The aim of this comprehensive overview is to provide an up-to-date insight into the distribution and properties of the well established granin-derived peptides and their putative roles in homeostatic regulations. Hence, focus is directed to peptides derived from the three main granins, e.g. to the chromogranin A derived vasostatins, betagranins, pancreastatin and catestatins, the chromogranin B-derived secretolytin and the secretogranin II-derived secretoneurin (SN). In addition, the distribution and properties of the chromogranin A-derived peptides prochromacin, chromofungin, WE14, parastatin, GE-25 and serpinins, the CgB-peptide PE-11 and the SgII-peptides EM66 and manserin will also be commented on. Finally, the opposing effects of the CgA-derived vasostatin-I and catestatin and the SgII-derived peptide SN on the integrity of the vasculature, myocardial contractility, angiogenesis in wound healing, inflammatory conditions and tumors will be discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Peptide Optical waveguides.

    Science.gov (United States)

    Handelman, Amir; Apter, Boris; Shostak, Tamar; Rosenman, Gil

    2017-02-01

    Small-scale optical devices, designed and fabricated onto one dielectric substrate, create integrated optical chip like their microelectronic analogues. These photonic circuits, based on diverse physical phenomena such as light-matter interaction, propagation of electromagnetic waves in a thin dielectric material, nonlinear and electro-optical effects, allow transmission, distribution, modulation, and processing of optical signals in optical communication systems, chemical and biological sensors, and more. The key component of these optical circuits providing both optical processing and photonic interconnections is light waveguides. Optical confinement and transmitting of the optical waves inside the waveguide material are possible due to the higher refractive index of the waveguides in comparison with their surroundings. In this work, we propose a novel field of bionanophotonics based on a new concept of optical waveguiding in synthetic elongated peptide nanostructures composed of ordered peptide dipole biomolecules. New technology of controllable deposition of peptide optical waveguiding structures by nanofountain pen technique is developed. Experimental studies of refractive index, optical transparency, and linear and nonlinear waveguiding in out-of-plane and in-plane diphenylalanine peptide nanotubes have been conducted. Optical waveguiding phenomena in peptide structures are simulated by the finite difference time domain method. The advantages of this new class of bio-optical waveguides are high refractive index contrast, wide spectral range of optical transparency, large optical nonlinearity, and electro-optical effect, making them promising for new applications in integrated multifunctional photonic circuits. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  12. Phosphorylated Peptide Functionalization of Lanthanide Upconversion Nanoparticles for Tuning Nanomaterial-Cell Interactions.

    Science.gov (United States)

    Yao, Chi; Wei, Caiyi; Huang, Zhi; Lu, Yiqing; El-Toni, Ahmed Mohamed; Ju, Dianwen; Zhang, Xiangmin; Wang, Wenning; Zhang, Fan

    2016-03-23

    Peptide modification of nanoparticles with high efficiency is critical in determining the properties and bioapplications of nanoparticles, but the methodology remains a challenging task. Here, by using the phosphorylated linear and cyclic peptide with the arginine-glycine-aspartic acid (RGD) targeting motifs as typical examples, the peptides binding efficiency for the inorganic metal compound nanoparticles was increased significantly after the phosphorylation treatment, and the modification allowed for improving the selectivity and signal-to-noise ratio for cancer targeting and reduced the toxicity derived from nonspecific interactions of nanoparticles with cells owing to the higher amount of phosphopeptide binding. In addition, molecular dynamics (MD) simulations of various peptides on inorganic metal compound surfaces revealed that the peptide adsorption on the surface is mainly driven by electrostatic interactions between phosphate oxygen and the polarized interfacial water layer, consistent with the experimental observation of the strong binding propensity of phosphorylated peptides. Significantly, with the RGD phosphopeptide surface modification, these nanoparticles provide a versatile tool for tuning material-cell interactions to achieve the desired level of autophagy and may prove useful for various diagnostic and therapeutic applications.

  13. Changes in D-aspartic acid and D-glutamic acid levels in the tissues and physiological fluids of mice with various D-aspartate oxidase activities.

    Science.gov (United States)

    Han, Hai; Miyoshi, Yurika; Koga, Reiko; Mita, Masashi; Konno, Ryuichi; Hamase, Kenji

    2015-12-10

    D-Aspartic acid (D-Asp) and D-glutamic acid (D-Glu) are currently paid attention as modulators of neuronal transmission and hormonal secretion. These two D-amino acids are metabolized only by D-aspartate oxidase (DDO) in mammals. Therefore, in order to design and develop new drugs controlling the D-Asp and D-Glu amounts via regulation of the DDO activities, changes in these acidic D-amino acid amounts in various tissues are expected to be clarified in model animals having various DDO activities. In the present study, the amounts of Asp and Glu enantiomers in 6 brain tissues, 11 peripheral tissues and 2 physiological fluids of DDO(+/+), DDO(+/-) and DDO(-/-) mice were determined using a sensitive and selective two-dimensional HPLC system. As a result, the amounts of D-Asp were drastically increased with the decrease in the DDO activity in all the tested tissues and physiological fluids. On the other hand, the amounts of D-Glu were almost the same among the 3 strains of mice. The present results are useful for designing new drug candidates, such as DDO inhibitors, and further studies are expected. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Diversity-oriented peptide stapling

    DEFF Research Database (Denmark)

    Tran, Thu Phuong; Larsen, Christian Ørnbøl; Røndbjerg, Tobias

    2017-01-01

    The introduction of macrocyclic constraints in peptides (peptide stapling) is an important tool within peptide medicinal chemistry for stabilising and pre-organising peptides in a desired conformation. In recent years, the copper-catalysed azide-alkyne cycloaddition (CuAAC) has emerged...... as a powerful method for peptide stapling. However, to date CuAAC stapling has not provided a simple method for obtaining peptides that are easily diversified further. In the present study, we report a new diversity-oriented peptide stapling (DOPS) methodology based on CuAAC chemistry. Stapling of peptides...... incorporating two azide-modified amino acids with 1,3,5-triethynylbenzene efficiently provides (i, i+7)- and (i, i+9)-stapled peptides with a single free alkyne positioned on the staple, that can be further conjugated or dimerised. A unique feature of the present method is that it provides easy access...

  15. Effects of Glutamate and Aspartate on Serum Antioxidative Enzyme, Sex Hormones, and Genital Inflammation in Boars Challenged with Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Hengjia Ni

    2016-01-01

    Full Text Available Background. Oxidative stress is associated with infertility. This study was conducted to determine the effects of glutamate and aspartate on serum antioxidative enzymes, sex hormones, and genital inflammation in boars suffering from oxidative stress. Methods. Boars were randomly divided into 4 groups: the nonchallenged control (CON and H2O2-challenged control (BD groups were fed a basal diet supplemented with 2% alanine; the other two groups were fed the basal diet supplemented with 2% glutamate (GLU or 2% aspartate (ASP. The BD, GLU, and ASP groups were injected with hydrogen peroxide (H2O2 on day 15. The CON group was injected with 0.9% sodium chloride solution on the same day. Results. Dietary aspartate decreased the malondialdehyde (MDA level in serum (P<0.05 compared with the BD group. Additionally, aspartate maintained serum luteinizing hormone (LH at a relatively stable level. Moreover, glutamate and aspartate increased transforming growth factor-β1 (TGF-β1 and interleukin-10 (IL-10 levels in the epididymis and testis (P<0.05 compared with the BD group. Conclusion. Both glutamate and aspartate promoted genital mRNA expressions of anti-inflammatory factors after oxidative stress. Aspartate more effectively decreased serum MDA and prevented fluctuations in serum sex hormones after H2O2 challenge than did glutamate.

  16. Neutron reflectivity and external reflection FTIR studies of DL-aspartic acid crystallization beneath nylon 6 spread films.

    Science.gov (United States)

    Jamieson, Matthew J; Cooper, Sharon J; Miller, Aline F; Holt, Stephen A

    2004-04-27

    The crystallization of DL-aspartic acid beneath nylon 6 spread films has been studied for 150% supersaturated systems using neutron reflectivity and external reflection FTIR. The neutron reflectivity data showed the gradual incorporation of DL-aspartic acid within a nylon 6 spread film layer over a period of 6-8 h, culminating in over 50 vol % of the "film" layer comprising DL-aspartic acid. Accumulation of further DL-aspartic acid material to produce microscopic/macroscopic surface crystals occurred, but on a more limited scale, resulting in approximately 1-5% surface coverage of crystals over the same period. External reflection FTIR studies revealed very weak bands attributable to DL-aspartic acid in surface regions devoid of visible crystals, in agreement with the neutron reflectivity studies. In regions with visible crystals, much larger and sharper DL-aspartic acid bands were seen. Changes in the intensity of the nylon 6 NH stretch band were often observed during the visible crystallization and dissolution of DL-aspartic acid and were consistent with the reversible accumulation of nylon 6 around the growing crystals.

  17. Chemical Derivatization of Peptide Carboxyl Groups for Highly Efficient Electron Transfer Dissociation

    Science.gov (United States)

    Frey, Brian L.; Ladror, Daniel T.; Sondalle, Samuel B.; Krusemark, Casey J.; Jue, April L.; Coon, Joshua J.; Smith, Lloyd M.

    2013-11-01

    The carboxyl groups of tryptic peptides were derivatized with a tertiary or quaternary amine labeling reagent to generate more highly charged peptide ions that fragment efficiently by electron transfer dissociation (ETD). All peptide carboxyl groups—aspartic and glutamic acid side-chains as well as C-termini—were derivatized with an average reaction efficiency of 99 %. This nearly complete labeling avoids making complex peptide mixtures even more complex because of partially-labeled products, and it allows the use of static modifications during database searching. Alkyl tertiary amines were found to be the optimal labeling reagent among the four types tested. Charge states are substantially higher for derivatized peptides: a modified tryptic digest of bovine serum albumin (BSA) generates ~90% of its precursor ions with z > 2, compared with less than 40 % for the unmodified sample. The increased charge density of modified peptide ions yields highly efficient ETD fragmentation, leading to many additional peptide identifications and higher sequence coverage (e.g., 70 % for modified versus only 43 % for unmodified BSA). The utility of this labeling strategy was demonstrated on a tryptic digest of ribosomal proteins isolated from yeast cells. Peptide derivatization of this sample produced an increase in the number of identified proteins, a >50 % increase in the sequence coverage of these proteins, and a doubling of the number of peptide spectral matches. This carboxyl derivatization strategy greatly improves proteome coverage obtained from ETD-MS/MS of tryptic digests, and we anticipate that it will also enhance identification and localization of post-translational modifications.

  18. Antimicrobial Peptides from Plants

    Directory of Open Access Journals (Sweden)

    James P. Tam

    2015-11-01

    Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.

  19. Peptide Integrated Optics.

    Science.gov (United States)

    Handelman, Amir; Lapshina, Nadezda; Apter, Boris; Rosenman, Gil

    2018-02-01

    Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Aspartic protease activities of schistosomes cleave mammalian hemoglobins in a host-specific manner

    Directory of Open Access Journals (Sweden)

    Jeffrey W Koehler

    2007-02-01

    Full Text Available We examined the efficiency of digestion of hemoglobin from four mammalian species, human, cow, sheep, and horse by acidic extracts of mixed sex adults of Schistosoma japonicum and S. mansoni. Activity ascribable to aspartic protease(s from S. japonicum and S. mansoni cleaved human hemoglobin. In addition, aspartic protease activities from S. japonicum cleaved hemoglobin from bovine, sheep, and horse blood more efficiently than did the activity from extracts of S. mansoni. These findings support the hypothesis that substrate specificity of hemoglobin-degrading proteases employed by blood feeding helminth parasites influences parasite host species range; differences in amino acid sequences in key sites of the parasite proteases interact less or more efficiently with the hemoglobins of permissive or non-permissive hosts.

  1. Improved postprandial glycaemic control with insulin Aspart in type 2 diabetic patients treated with insulin

    DEFF Research Database (Denmark)

    Rosenfalck, A M; Thorsby, P; Kjems, L

    2000-01-01

    The effect on postprandial blood glucose control of an immediately pre-meal injection of the rapid acting insulin analogue Aspart (IAsp) was compared with that of human insulin Actrapid injected immediately or 30 minutes before a test meal in insulin-treated type 2 diabetic patients with residual.......0 nmol/l (range, 0.3-2.5) and diabetes duration 12.5 years (range, 3.0-26.0). Twenty-two patients completed the study. A significantly improved postprandial glucose control was demonstrated with IAsp as compared to Act0, based on a significantly smaller postprandial blood glucose excursion (IAsp, 899......-meal administration of the rapid-acting insulin analogue Aspart in patients with type 2 diabetes resulted in an improved postprandial glucose control compared to Actrapid injected immediately before the meal, but showed similar control compared to Actrapid injected 30 minutes before the meal. These results indicate...

  2. Crystallographic Snapshots of the Complete Catalytic Cycle of the Unregulated Aspartate Transcarbamoylase from Bacillus subtilis

    Energy Technology Data Exchange (ETDEWEB)

    K Harris; G Cockrell; D Puleo; E Kantrowitz

    2011-12-31

    Here, we report high-resolution X-ray structures of Bacillus subtilis aspartate transcarbamoylase (ATCase), an enzyme that catalyzes one of the first reactions in pyrimidine nucleotide biosynthesis. Structures of the enzyme have been determined in the absence of ligands, in the presence of the substrate carbamoyl phosphate, and in the presence of the bisubstrate/transition state analog N-phosphonacetyl-L-aspartate. Combining the structural data with in silico docking and electrostatic calculations, we have been able to visualize each step in the catalytic cycle of ATCase, from the ordered binding of the substrates, to the formation and decomposition of the tetrahedral intermediate, to the ordered release of the products from the active site. Analysis of the conformational changes associated with these steps provides a rationale for the lack of cooperativity in trimeric ATCases that do not possess regulatory subunits.

  3. The N-terminal region of mature mitochondrial aspartate aminotransferase can direct cytosolic dihydrofolate reductase into mitochondria in vitro.

    Science.gov (United States)

    Giannattasio, S; Azzariti, A; Marra, E; Quagliariello, E

    1994-06-30

    Two fused genes were constructed which encode for two chimeric proteins in which either 10 or 191 N-terminal amino acids of mature mitochondrial aspartate aminotransferase had been attached to the entire polypeptide chain of cytosolic dihydrofolate reductase. The precursor and mature form of mitochondrial aspartate aminotransferase, dihydrofolate reductase and both chimeric proteins were synthesized in vitro and their import into isolated mitochondria was studied. Both chimeric proteins were taken up by isolated organelles, where they became protease resistant, thus indicating the ability of the N-terminal portion of the mature moiety of the precursor of mitochondrial aspartate aminotransferase to direct cytosolic dihydrofolate reductase into mitochondria.

  4. Interaction Studies of Secreted Aspartic Proteases (Saps) from Candida albicans : Application for Drug Discovery

    OpenAIRE

    Backman, Dan

    2005-01-01

    This thesis is focused on enzymatic studies of the secreted aspartic proteases (Saps) from Candida albicans as a tool for discovery of anti-candida drugs. C. albicans causes infections in a number of different locations, which differ widely in the protein substrates available and pH. Since C. albicans needs Saps during virulent growth, these enzymes are good targets for drug development. In order to investigate the catalytic characteristics of Saps and their inhibitor affinities, substrate-ba...

  5. Diversion of aspartate in ASS1-deficient tumours fosters de novo pyrimidine synthesis.

    Science.gov (United States)

    Rabinovich, Shiran; Adler, Lital; Yizhak, Keren; Sarver, Alona; Silberman, Alon; Agron, Shani; Stettner, Noa; Sun, Qin; Brandis, Alexander; Helbling, Daniel; Korman, Stanley; Itzkovitz, Shalev; Dimmock, David; Ulitsky, Igor; Nagamani, Sandesh Cs; Ruppin, Eytan; Erez, Ayelet

    2015-11-19

    Cancer cells hijack and remodel existing metabolic pathways for their benefit. Argininosuccinate synthase (ASS1) is a urea cycle enzyme that is essential in the conversion of nitrogen from ammonia and aspartate to urea. A decrease in nitrogen flux through ASS1 in the liver causes the urea cycle disorder citrullinaemia. In contrast to the well-studied consequences of loss of ASS1 activity on ureagenesis, the purpose of its somatic silencing in multiple cancers is largely unknown. Here we show that decreased activity of ASS1 in cancers supports proliferation by facilitating pyrimidine synthesis via CAD (carbamoyl-phosphate synthase 2, aspartate transcarbamylase, and dihydroorotase complex) activation. Our studies were initiated by delineating the consequences of loss of ASS1 activity in humans with two types of citrullinaemia. We find that in citrullinaemia type I (CTLN I), which is caused by deficiency of ASS1, there is increased pyrimidine synthesis and proliferation compared with citrullinaemia type II (CTLN II), in which there is decreased substrate availability for ASS1 caused by deficiency of the aspartate transporter citrin. Building on these results, we demonstrate that ASS1 deficiency in cancer increases cytosolic aspartate levels, which increases CAD activation by upregulating its substrate availability and by increasing its phosphorylation by S6K1 through the mammalian target of rapamycin (mTOR) pathway. Decreasing CAD activity by blocking citrin, the mTOR signalling, or pyrimidine synthesis decreases proliferation and thus may serve as a therapeutic strategy in multiple cancers where ASS1 is downregulated. Our results demonstrate that ASS1 downregulation is a novel mechanism supporting cancerous proliferation, and they provide a metabolic link between the urea cycle enzymes and pyrimidine synthesis.

  6. Lowered circulating aspartate is a metabolic feature of human breast cancer

    OpenAIRE

    Xie, Guoxiang; Zhou, Bingsen; Zhao, Aihua; Qiu, Yunping; Zhao, Xueqing; Garmire, Lana; Shvetsov, Yurii B.; Yu, Herbert; Yen, Yun; Jia, Wei

    2015-01-01

    Distinct metabolic transformation is essential for cancer cells to sustain a high rate of proliferation and resist cell death signals. Such a metabolic transformation results in unique cellular metabolic phenotypes that are often reflected by distinct metabolite signatures in tumor tissues as well as circulating blood. Using a metabolomics platform, we find that breast cancer is associated with significantly (p = 6.27E-13) lowered plasma aspartate levels in a training group comprising 35 brea...

  7. Differential Aspartate Usage Identifies a Subset of Cancer Cells Particularly Dependent on OGDH

    OpenAIRE

    Eric L. Allen; Danielle B. Ulanet; David Pirman; Christopher E. Mahoney; John Coco; Yaguang Si; Ying Chen; Lingling Huang; Jinmin Ren; Sung Choe; Michelle F. Clasquin; Erin Artin; Zi Peng Fan; Giovanni Cianchetta; Joshua Murtie

    2016-01-01

    Although aberrant metabolism in tumors has been well described, the identification of cancer subsets with particular metabolic vulnerabilities has remained challenging. Here, we conducted an siRNA screen focusing on enzymes involved in the tricarboxylic acid (TCA) cycle and uncovered a striking range of cancer cell dependencies on OGDH, the E1 subunit of the alpha-ketoglutarate dehydrogenase complex. Using an integrative metabolomics approach, we identified differential aspartate utilization,...

  8. Supporting aspartate biosynthesis is an essential function of respiration in proliferating cells

    OpenAIRE

    Sullivan, Lucas B.; Gui, Dan Y.; Hosios, Aaron M.; Bush, Lauren N.; Freinkman, Elizaveta; Vander Heiden, Matthew G.

    2015-01-01

    Mitochondrial respiration is important for cell proliferation, however the specific metabolic requirements fulfilled by respiration to support proliferation have not been defined. Here we show that a major role of respiration in proliferating cells is to provide electron acceptors for aspartate synthesis. This finding is consistent with the observation that cells lacking a functional respiratory chain are auxotrophic for pyruvate, which serves as an exogenous electron acceptor. Further, the p...

  9. Anti-N-methyl-D-aspartate receptor encephalitis with favorable outcome despite prolonged status epilepticus

    OpenAIRE

    Finné Lenoir, Xavier; Sindic, Christian; Van Pesch, Vincent; El Sankari, Souraya; de Tourtchaninoff, Marianne; Denays, Roger; Hantson, Philippe

    2013-01-01

    BACKGROUND: To describe a case of auto-immune encephalitis in an adolescent with favorable outcome despite prolonged status epilepticus. METHODS: A 17 year old Asian man without previous medical history developed alteration of consciousness and partial seizures. The diagnosis of anti-N-methyl-D-aspartate receptor encephalitis was confirmed by the detection of specific antibodies in both cerebrospinal fluid and serum. RESULTS: The clinical course was complicated by prolonged status epilepticus...

  10. In vitro effects of sodium benzoate on the activities of aspartate and ...

    African Journals Online (AJOL)

    The in vitro effects of varying concentrations sodium benzoate on the activities of aspartate (E.C. 2.6.1.1) and alanine (E.C. 2.6.1.2) aminotransferases (AST and ALT, respectively) and alkaline phosphatase (E.C. 3.1.3.1; abbreviated as ALP) from human erythrocytes of different genotypes (HbAA, HbAS and HbSS) were ...

  11. Extending crystallographic information with semiempirical quantum mechanics and molecular mechanics: a case of aspartic proteinases.

    Science.gov (United States)

    Goldblum, A; Rayan, A; Fliess, A; Glick, M

    1993-01-01

    The results of crystallographic analysis of a complex between an aspartic proteinase, endothiapepsin, and an inhibitor have been extended through the assignment of protons in the active site, to study various steps in the reaction with a substrate. Mechanistic implications are suggested as a consequence of semiempirical quantum mechanical calculations, indicating that most of the activation energy is required to bring the substrate from an initial binding mode to close distance to a water molecule.

  12. N-(Fluoren-9-ylmethoxycarbonyl-l-aspartic acid 4-tert-butyl ester

    Directory of Open Access Journals (Sweden)

    Kazuhiko Yamada

    2009-11-01

    Full Text Available The bond distances and bond angles of the title compound, C23H25NO6, are consistent with values typically found for fluoren-9-ylmethoxycarbonyl-protected amino acids. The conformations of the backbone and the side chain are slightly different from those of l-aspartic acid. The crystal structure exhibits two intermolecular hydrogen bonds, forming a two-dimensional sheet structure parallel to the ab plane.

  13. Age estimation in forensic sciences: Application of combined aspartic acid racemization and radiocarbon analysis

    Energy Technology Data Exchange (ETDEWEB)

    Alkass, K; Buchholz, B A; Ohtani, S; Yamamoto, T; Druid, H; Spalding, S L

    2009-11-02

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster, since the age at death, birth date and year of death, as well as gender, can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization has shown reproducible and more precise results. In this paper we analyze teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that above-ground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ({sup 14}C) which have been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel and ten of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R2=0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 0.6 {+-} 04 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 {+-} 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification.

  14. Combination of aspartic acid and glutamic acid inhibits tumor cell proliferation.

    Science.gov (United States)

    Yamaguchi, Yoshie; Yamamoto, Katsunori; Sato, Yoshinori; Inoue, Shinjiro; Morinaga, Tetsuo; Hirano, Eiichi

    2016-01-01

    Placental extract contains several biologically active compounds, and pharmacological induction of placental extract has therapeutic effects, such as improving liver function in patients with hepatitis or cirrhosis. Here, we searched for novel molecules with an anti-tumor activity in placental extracts. Active molecules were separated by chromatographic analysis, and their antiproliferative activities were determined by a colorimetric assay. We identified aspartic acid and glutamic acid to possess the antiproliferative activity against human hepatoma cells. Furthermore, we showed that the combination of aspartic acid and glutamic acid exhibited enhanced antiproliferative activity, and inhibited Akt phosphorylation. We also examined in vivo tumor inhibition activity using the rabbit VX2 liver tumor model. The treatment mixture (emulsion of the amino acids with Lipiodol) administered by hepatic artery injection inhibited tumor cell growth of the rabbit VX2 liver. These results suggest that the combination of aspartic acid and glutamic acid may be useful for induction of tumor cell death, and has the potential for clinical use as a cancer therapeutic agent.

  15. The Pathway of Product Release from the R State of Aspartate Transcarbamoylase

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, K.; Kantrowitz, E

    2010-01-01

    The pathway of product release from the R state of aspartate transcarbamoylase (ATCase; EC 2.1.3.2, aspartate carbamoyltransferase) has been determined here by solving the crystal structure of Escherichia coli ATCase locked in the R quaternary structure by specific introduction of disulfide bonds. ATCase displays ordered substrate binding and product release, remaining in the R state until substrates are exhausted. The structure reported here represents ATCase in the R state bound to the final product molecule, phosphate. This structure has been difficult to obtain previously because the enzyme relaxes back to the T state after the substrates are exhausted. Hence, cocrystallizing the wild-type enzyme with phosphate results in a T-state structure. In this structure of the enzyme trapped in the R state with specific disulfide bonds, we observe two phosphate molecules per active site. The position of the first phosphate corresponds to the position of the phosphate of carbamoyl phosphate (CP) and the position of the phosphonate of N-phosphonacetyl-L-aspartate. However, the second, more weakly bound phosphate is bound in a positively charged pocket that is more accessible to the surface than the other phosphate. The second phosphate appears to be on the path that phosphate would have to take to exit the active site. Our results suggest that phosphate dissociation and CP binding can occur simultaneously and that the dissociation of phosphate may actually promote the binding of CP for more efficient catalysis.

  16. Characterization of Aspartate Kinase from Corynebacterium pekinense and the Critical Site of Arg169

    Directory of Open Access Journals (Sweden)

    Weihong Min

    2015-11-01

    Full Text Available Aspartate kinase (AK is the key enzyme in the biosynthesis of aspartate-derived amino acids. Recombinant AK was efficiently purified and systematically characterized through analysis under optimal conditions combined with steady-state kinetics study. Homogeneous AK was predicted as a decamer with a molecular weight of ~48 kDa and a half-life of 4.5 h. The enzymatic activity was enhanced by ethanol and Ni2+. Moreover, steady-state kinetic study confirmed that AK is an allosteric enzyme, and its activity was inhibited by allosteric inhibitors, such as Lys, Met, and Thr. Theoretical results indicated the binding mode of AK and showed that Arg169 is an important residue in substrate binding, catalytic domain, and inhibitor binding. The values of the kinetic parameter Vmax of R169 mutants, namely, R169Y, R169P, R169D, and R169H AK, with l-aspartate as the substrate, were 4.71-, 2.25-, 2.57-, and 2.13-fold higher, respectively, than that of the wild-type AK. Furthermore, experimental and theoretical data showed that Arg169 formed a hydrogen bond with Glu92, which functions as the entrance gate. This study provides a basis to develop new enzymes and elucidate the corresponding amino acid production.

  17. New insights into the metabolism of aspartate-family amino acids in plant seeds.

    Science.gov (United States)

    Wang, Wenyi; Xu, Mengyun; Wang, Guoping; Galili, Gad

    2018-02-05

    Aspartate-family amino acids. Aspartate (Asp)-family pathway, via several metabolic branches, leads to four key essential amino acids: Lys, Met, Thr, and Ile. Among these, Lys and Met have received the most attention, as they are the most limiting amino acid in cereals and legumes crops, respectively. The metabolic pathways of these four essential amino acids and their interactions with regulatory networks have been well characterized. Using this knowledge, extensive efforts have been devoted to augmenting the levels of these amino acids in various plant organs, especially seeds, which serve as the main source of human food and livestock feed. Seeds store a number of storage proteins, which are utilized as nutrient and energy resources. Storage proteins are composed of amino acids, to guarantee the continuation of plant progeny. Thus, understanding the seed metabolism, especially with respect to the accumulation of aspartate-derived amino acids Lys and Met, is a crucial factor for sustainable agriculture. In this review, we summarized the Asp-family pathway, with some new examples of accumulated Asp-family amino acids, particularly Lys and Met, in plant seeds. We also discuss the recent advances in understanding the roles of Asp-family amino acids during seed development.

  18. N-Methyl-D-aspartic Acid (NMDA in the nervous system of the amphioxus Branchiostoma lanceolatum

    Directory of Open Access Journals (Sweden)

    Garcia-Fernàndez Jordi

    2007-12-01

    Full Text Available Abstract Background NMDA (N-methyl-D-aspartic acid is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone in the hypothalamus, and of LH (Luteinizing Hormone and PRL (Prolactin in the pituitary gland. Results In this study we show evidence for the occurrence of endogenous NMDA in the amphioxus Branchiostoma lanceolatum. A relatively high concentration of NMDA occurs in the nervous system of this species (3.08 ± 0.37 nmol/g tissue in the nerve cord and 10.52 ± 1.41 nmol/g tissue in the cephalic vesicle. As in rat, in amphioxus NMDA is also biosynthesized from D-aspartic acid (D-Asp by a NMDA synthase (also called D-aspartate methyl transferase. Conclusion Given the simplicity of the amphioxus nervous and endocrine systems compared to mammalian, the discovery of NMDA in this protochordate is important to gain insights into the role of endogenous NMDA in the nervous and endocrine systems of metazoans and particularly in the chordate lineage.

  19. Magnitude of malate-aspartate reduced nicotinamide adenine dinucleotide shuttle activity in intact respiring tumor cells.

    Science.gov (United States)

    Greenhouse, W V; Lehninger, A L

    1977-11-01

    Measurements of respiration, CO2 and lactate production, and changes in the levels of various key metabolites of the glycolytic sequence and tricarboxylic acid cycle were made on five lines of rodent ascites tumor cells (two strains of Ehrlich ascites tumor cells, Krebs II carcinoma, AS-30D carcinoma, and L1210 cells) incubated aerobically in the presence of uniformly labeled D-[14C]glucose. From these data, as well as earlier evidence demonstrating that the reduced nicotinamide adenine dinucleotide (NADH) shuttle in these cells requires a transaminase step and is thus identified as the malate-aspartate shuttle (W.V.V. Greenhouse and A.L. Lehninger, Cancer Res., 36: 1392-1396, 1976), metabolic flux diagrams were constructed for the five cell lines. These diagrams show the relative rates of glycolysis, the tricarboxylic acid cycle, electron transport, and the malate-aspartate shuttle in these tumors. Large amounts of cytosolic NADH were oxidized by the mitochondrial respiratory chain via the NADH shuttle, comprising anywhere from about 20 to 80% of the total flow of reducing equivalents to oxygen in these tumors. Calculations of the sources of energy for adenosine triphosphate synthesis indicated that on the average about one-third of the respiratory adenosine triphosphate is generated by electron flow originating from cytosolic NADH via the malate-aspartate shuttle.

  20. Biomimetic peptide nanosensors.

    Science.gov (United States)

    Cui, Yue; Kim, Sang N; Naik, Rajesh R; McAlpine, Michael C

    2012-05-15

    The development of a miniaturized sensing platform tailored for sensitive and selective detection of a variety of biochemical analytes could offer transformative fundamental and technological opportunities. Due to their high surface-to-volume ratios, nanoscale materials are extremely sensitive sensors. Likewise, peptides represent robust substrates for selective recognition due to the potential for broad chemical diversity within their relatively compact size. Here we explore the possibilities of linking peptides to nanosensors for the selective detection of biochemical targets. Such systems raise a number of interesting fundamental challenges: What are the peptide sequences, and how can rational design be used to derive selective binders? What nanomaterials should be used, and what are some strategies for assembling hybrid nanosensors? What role does molecular modeling play in elucidating response mechanisms? What is the resulting performance of these sensors, in terms of sensitivity, selectivity, and response time? What are some potential applications? This Account will highlight our early attempts to address these research challenges. Specifically, we use natural peptide sequences or sequences identified from phage display as capture elements. The sensors are based on a variety of nanomaterials including nanowires, graphene, and carbon nanotubes. We couple peptides to the nanomaterial surfaces via traditional surface functionalization methods or self-assembly. Molecular modeling provides detailed insights into the hybrid nanostructure, as well as the sensor detection mechanisms. The peptide nanosensors can distinguish chemically camouflaged mixtures of vapors and detect chemical warfare agents with sensitivities as low as parts-per-billion levels. Finally, we anticipate future uses of this technology in biomedicine: for example, devices based on these sensors could detect disease from the molecular components in human breath. Overall, these results provide a

  1. Evaluation of the therapeutic effect of Nigella sativa crude oil and its blend with omega-3 fatty acid-rich oils in a modified hepatorenal syndrome model in rats

    Directory of Open Access Journals (Sweden)

    Al-Okbi, S. Y.

    2015-12-01

    Full Text Available In the present study, the hepato and reno-protective effect of Nigella sativa crude oil and its binary blend with omega-3 fatty acid-rich oils (fish and flaxseed oils was studied in a modified hepatorenal syndrome model (MHRS in rats. MHRS was induced through feeding a high fructose diet followed by an intraperitoneal injection of galactosamine hydrochloride. Nigella oil and its different blends were given as a daily oral dose to MHRS rats. Two control groups of MHRS and normal healthy rats were run. Different biochemical and nutritional parameters were assessed. The induction of MHRS produced liver and kidney dysfunction, and elevated oxidative stress, an inflammatory biomarker, endothelin 1, and plasma cholesterol. Reduced plasma high density lipoprotein cholesterol, albumin and Ca and elevated urinary N-acetyl-β-D-Glucosaminidase and liver fats were noticed. The administration of Nigella crude oil that originally had 0.2% total omega-3 fatty acids or its blend with fish oil (17.9% omega-3 or flaxseed oil (42.1% omega-3 significantly improved all biochemical parameters of MHRS. There was no significant difference in the biochemical parameters among the different oil treated groups regardless of the omega-3 fatty acid content. This may point out to the potential profound effect of the volatile oil fraction of Nigella crude oil which may compensates for its low omega-3 content.En el presente estudio, el efecto hepato- y reno-protector de aceites crudos de Nigella sativa y su mezcla binaria con aceites ricos en ácidos grasos omega-3 (pescado y aceites de linaza fue estudiado en un modelo modificado de síndrome hepatorenal (MHRS en ratas. MHRS fue inducido a través de la alimentación de una dieta alta en fructosa seguido de la inyección intraperitoneal de clorhidrato de galactosamina. Diferentes aceites fueron suministrados como dosis oral diaria a ratas con MHRS. Se realizaron dos grupos de control de MHRS y ratas sanas normales. Se

  2. Immunotherapy with Allergen Peptides

    Directory of Open Access Journals (Sweden)

    Larché Mark

    2007-06-01

    Full Text Available Specific allergen immunotherapy (SIT is disease-modifying and efficacious. However, the use of whole allergen preparations is associated with frequent allergic adverse events during treatment. Many novel approaches are being designed to reduce the allergenicity of immunotherapy preparations whilst maintaining immunogenicity. One approach is the use of short synthetic peptides which representing dominant T cell epitopes of the allergen. Short peptides exhibit markedly reduced capacity to cross link IgE and activate mast cells and basophils, due to lack of tertiary structure. Murine pre-clinical studies have established the feasibility of this approach and clinical studies are currently in progress in both allergic and autoimmune diseases.

  3. Therapeutic HIV Peptide Vaccine

    DEFF Research Database (Denmark)

    Fomsgaard, Anders

    2015-01-01

    Therapeutic vaccines aim to control chronic HIV infection and eliminate the need for lifelong antiretroviral therapy (ART). Therapeutic HIV vaccine is being pursued as part of a functional cure for HIV/AIDS. We have outlined a basic protocol for inducing new T cell immunity during chronic HIV-1...... infection directed to subdominant conserved HIV-1 epitopes restricted to frequent HLA supertypes. The rationale for selecting HIV peptides and adjuvants are provided. Peptide subunit vaccines are regarded as safe due to the simplicity, quality, purity, and low toxicity. The caveat is reduced immunogenicity...

  4. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac....... An inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...... competent endocrine cells. The structurally related atrial natriuretic peptide will be mentioned where appropriate, whereas C-type natriuretic peptide will not be considered as a cardiac peptide of relevance in mammalian physiology....

  5. Glucocorticoid receptor activation selectively hampers N-methyl-d-aspartate receptor dependent hippocampal synaptic plasticity in vitro.

    NARCIS (Netherlands)

    Wiegert, O.; Pu, Z.; Shor, S.; Joëls, M.; Krugers, H.

    2005-01-01

    Corticosterone and exposure to stressful experiences have been reported to decrease hippocampal synaptic plasticity, in particular when relatively mild stimulation paradigms-presumably activating predominantly N-methyl-d-aspartate receptors-are being used. Using various stimulation paradigms and

  6. Sequence, Structural Analysis and Metrics to Define the Unique Dynamic Features of the Flap Regions Among Aspartic Proteases.

    Science.gov (United States)

    McGillewie, Lara; Ramesh, Muthusamy; Soliman, Mahmoud E

    2017-10-01

    Aspartic proteases are a class of hydrolytic enzymes that have been implicated in a number of diseases such as HIV, malaria, cancer and Alzheimer's. The flap region of aspartic proteases is a characteristic unique structural feature of these enzymes; and found to have a profound impact on protein overall structure, function and dynamics. Flap dynamics also plays a crucial role in drug binding and drug resistance. Therefore, understanding the structure and dynamic behavior of this flap regions is crucial in the design of potent and selective inhibitors against aspartic proteases. Defining metrics that can describe the flap motion/dynamics has been a challenging topic in literature. This review is the first attempt to compile comprehensive information on sequence, structure, motion and metrics used to assess the dynamics of the flap region of different aspartic proteases in "one pot". We believe that this review would be of critical importance to the researchers from different scientific domains.

  7. Anesthesia in anti-N-methyl-D-aspartate receptor encephalitis - is general anesthesia a requisite? A case report

    Directory of Open Access Journals (Sweden)

    Sook Hui Chaw

    Full Text Available Abstract Anti-N-methyl-D-aspartate receptor encephalitis is a recently described neurological disorder and an increasingly recognized cause of psychosis, movement disorders and autonomic dysfunction. We report 20-year-old Chinese female who presented with generalized tonic-clonic seizures, recent memory loss, visual hallucinations and abnormal behavior. Anti-N-methyl-D-aspartate receptor encephalitis was diagnosed and a computed tomography scan of abdomen reviewed a left adnexal tumor. We describe the first such case report of a patient with anti-N-methyl-D-aspartate receptor encephalitis who was given a bilateral transversus abdominis plane block as the sole anesthetic for removal of ovarian tumor. We also discuss the anesthetic issues associated with anti-N-methyl-D-aspartate receptor encephalitis. As discovery of tumor and its removal is the focus of initial treatment in this group of patients, anesthetists will encounter more such cases in the near future.

  8. Gamma-glutamyltransferase, aspartate aminotransferase and alkaline phosphatase as markers of alcohol consumption in out-patient alcoholics

    DEFF Research Database (Denmark)

    Gluud, C; Andersen, I; Dietrichson, O

    1981-01-01

    Serum activity of gamma-glutamyltransferase, aspartate aminotransferase and alkaline phosphatase were determined in 316 patients attending an out-patients clinic for treatment of alcoholism. The activity of gamma-glutamyltransferase was raised in 34% and that of aspartate aminotransferase...... and alkaline phosphatase in 18% and 7%. Neither the activity of gamma-glutamyltransferase, aspartate aminotransferase nor alkaline phosphatase showed any significant (P greater than 0.05) correlation with the history of alcohol consumption. The activities of gamma-glutamyltransferase and aspartate...... aminotransferase were raised significantly more often in patients with recent alcohol consumption than in patients who had abstained for more than 9 days. The concentration of alkaline phosphatase was not significantly (P greater than 0.05) different in these groups. The predictive value of raised and normal...

  9. Effects of D-aspartate treatment on D-aspartate oxidase, superoxide dismutase, and caspase 3 activities in frog (Rana esculenta) tissues.

    Science.gov (United States)

    Burrone, Lavinia; Di Giovanni, Marcello; Di Fiore, M Maddalena; Baccari, Gabriella Chieffi; Santillo, Alessandra

    2010-06-01

    Although D-aspartate (D-Asp) has been recognized to have a physiological role within different organs, high concentrations could elicit detrimental effects on those same organs. In this study, we examined the D-aspartate oxidase (D-AspO) activity and the expression of superoxide dismutase 1 (SOD1) and caspase 3 in different tissues of the frog Rana esculenta after chronic D-Asp treatment. Our in vivo experiments, consisting of intraperitoneal (ip) injections of D-Asp (2.0 micromol/g b.w.) in frogs for ten consecutive days, revealed that all examined tissues can take up and accumulate D-Asp. Further, in D-Asp treated frogs, i) the D-AspO activity significantly increased in all tissues (kidney, heart, testis, liver, and brain), ii) the SOD1 expression (antioxidant enzyme) significantly increased in the kidney, and iii) the caspase 3 level (indicative of apoptosis) increased in both brain and heart. Particularly, after the D-Asp treatment we found in both brain and heart (which showed the lowest SOD1 levels) a significant increase of the caspase 3 expression and, vice versa, in the kidney (which showed the highest SOD1 expression) a significant decrease of the caspase 3 expression. Therefore, we speculate that, in frog tissue, D-AspO plays an essential role in modulating the D-Asp concentration. In addition, exaggerated D-Asp concentrations activated SOD1 as cytoprotective mechanism in the kidney, whereas, in the brain and in the heart, where the antioxidant action of SOD1 is limited, caspase 3 was activated.

  10. GROUPS IN PEPTIDE SYNTHESIS

    African Journals Online (AJOL)

    carboxamide protecting group in peptide synthesis. RESULTS AND DISCUSSION l-Tetralinylamines used as precursors to prepare the carboxamide derivatives of asparagine and glutamine are shown in Table 1: Table 1. Summary of l-tetralinyl amines. Amines Aromatic ring NHZ. X Y Z Z. 1 H H H. 2 OCH; H H. 3 H OCH ...

  11. Natriuretic peptides and cerebral hemodynamics

    DEFF Research Database (Denmark)

    Guo, Song; Barringer, Filippa; Zois, Nora Elisabeth

    2014-01-01

    Natriuretic peptides have emerged as important diagnostic and prognostic tools for cardiovascular disease. Plasma measurement of the bioactive peptides as well as precursor-derived fragments is a sensitive tool in assessing heart failure. In heart failure, the peptides are used as treatment...

  12. NCAM Mimetic Peptides: An Update

    DEFF Research Database (Denmark)

    Berezin, Vladimir; Bock, Elisabeth

    2008-01-01

    of combinatorial peptide libraries. The C3 and NBP10 peptides target the first Ig module whereas the ENFIN2 and ENFIN11 peptides target fibronectin type III (FN3) modules of NCAM. A number of NCAM mimetics can induce neurite outgrowth and exhibit neuroprotective and synaptic plasticity modulating properties...

  13. 'optimization' of animal peptide toxins

    African Journals Online (AJOL)

    McRoy

    peptides of ca. 4 to 70 amino acid residues, with a number of potential therapeutic applications.[1]. Because of the intrinsic structural complexities of these peptides (different types of fold and 1-5 disulfide bridges), this size range implicates that only a fraction of them (< 50-mer peptides) can routinely be produced by ...

  14. Systematic Moiety Variations of Ultrashort Peptides Produce Profound Effects on Self-Assembly, Nanostructure Formation, Hydrogelation, and Phase Transition

    KAUST Repository

    Chan, Kiat Hwa

    2017-10-04

    Self-assembly of small biomolecules is a prevalent phenomenon that is increasingly being recognised to hold the key to building complex structures from simple monomeric units. Small peptides, in particular ultrashort peptides containing up to seven amino acids, for which our laboratory has found many biomedical applications, exhibit immense potential in this regard. For next-generation applications, more intricate control is required over the self-assembly processes. We seek to find out how subtle moiety variation of peptides can affect self-assembly and nanostructure formation. To this end, we have selected a library of 54 tripeptides, derived from systematic moiety variations from seven tripeptides. Our study reveals that subtle structural changes in the tripeptides can exert profound effects on self-assembly, nanostructure formation, hydrogelation, and even phase transition of peptide nanostructures. By comparing the X-ray crystal structures of two tripeptides, acetylated leucine-leucine-glutamic acid (Ac-LLE) and acetylated tyrosine-leucine-aspartic acid (Ac-YLD), we obtained valuable insights into the structural factors that can influence the formation of supramolecular peptide structures. We believe that our results have major implications on the understanding of the factors that affect peptide self-assembly. In addition, our findings can potentially assist current computational efforts to predict and design self-assembling peptide systems for diverse biomedical applications.

  15. Molecular Imaging of Breast Cancer: Role of RGD Peptides.

    Science.gov (United States)

    Chakravarty, Rubel; Chakraborty, Sudipta; Dash, Ashutosh

    2015-01-01

    Breast cancer is the leading cause of cancer deaths among women of all ages worldwide. With advances in molecular imaging procedures, it has been possible to detect breast cancer in its early stage, determine the extent of the disease to administer appropriate therapeutic protocol and also monitor the effects of treatment. By accurately characterizing the tumor properties and biological processes involved, molecular imaging can play a crucial role in minimizing the morbidity and mortality associated with breast cancer. The integrin αvβ3 plays an important role in breast cancer angiogenesis and is expressed on tumor endothelial cells as well as on some tumor cells. It is a receptor for the extracellular matrix proteins with the exposed arginine-glycine-aspartic acid (RGD) tripeptide sequence and therefore RGD peptides can preferentially bind to integrin αvβ3. In this context, targeting tumor vasculature or tumor cells by RGD-based probes is a promising strategy for molecular imaging of breast cancer. Using RGD-based probes, several preclinical studies have employed different imaging modalities such as positron emission tomography (PET), single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), ultrasound and optical imaging for visualization of integrin αvβ3 expression in breast cancer models. Limited clinical trials using (18)F-labeled RGD peptides have also been initiated for non-invasive detection and staging of breast cancer. Herein, we provide a comprehensive overview of the latest advances in molecular imaging of breast cancer using RGD peptide-based probes and discuss the challenges and opportunities for advancement of the field. The reported strategies for molecular imaging of breast cancer using RGD peptide-based probes holds promise for making clinically translatable advances that can positively impact the overall diagnostic and therapeutic processes and result in improved quality of life for breast cancer patients.

  16. Peptide vectors for gene delivery: from single peptides to multifunctional peptide nanocarriers.

    Science.gov (United States)

    Raad, Markus de; Teunissen, Erik A; Mastrobattista, Enrico

    2014-07-01

    The therapeutic use of nucleic acids relies on the availability of sophisticated delivery systems for targeted and intracellular delivery of these molecules. Such a gene delivery should possess essential characteristics to overcome several extracellular and intracellular barriers. Peptides offer an attractive platform for nonviral gene delivery, as several functional peptide classes exist capable of overcoming these barriers. However, none of these functional peptide classes contain all the essential characteristics required to overcome all of the barriers associated with successful gene delivery. Combining functional peptides into multifunctional peptide vectors will be pivotal for improving peptide-based gene delivery systems. By using combinatorial strategies and high-throughput screening, the identification of multifunctional peptide vectors will accelerate the optimization of peptide-based gene delivery systems.

  17. [Biosynthesis of opioid peptides].

    Science.gov (United States)

    Rossier, J

    1988-01-01

    The endogenous opioid peptides all contain the enkephalin sequence Tyr-Gly-Gly-Phe-Met and Tyr-Gly-Gly-Phe-Leu at their aminoterminus. Three distinct families of these peptides (endorphins, enkephalins and dynorphins) are present in different neuronal pathways within the central nervous system. Molecular genetics have shown that these three families of opioid peptides are derived from three distinct precursors. Pro-opiomelanocortin gives rise to the endorphins, as well as adrenocorticotropic hormone (ACTH) and the melanotropic hormones (MSH's). [Met] enkephalin, [Leu] enkephalin and the related heptapeptide [Met] enkephalin-Arg6-Phe7 and octapeptide [Met] enkephalin-Arg6-Gly7-Leu8 are derived from proenkephalin. The third family is derived from prodynorphin and includes dynorphin A, dynorphin B (also known as rimorphin) and alpha- and beta-neo-endorphin. The structure of the genes coding for these precursors are similar, suggesting the possibility of one common ancestral gene. The most common scheme for enzymatic maturation of precursors proposes the action of a trypsin-like endopeptidase followed by a carboxypeptidase B-like exopeptidase. However, we have provided evidence that this combination of trypsin-like and carboxypeptidase B-like enzymes may not be the only mechanism for liberating enkephalin from low molecular weight enkephalin-containing peptides. Indeed, endo-oligopeptidase A, an enzyme, known to hydrolyze the Phe5-Ser6 bond of bradykinin and the Arg8-Arg9 bond of neurotensin, has been shown to produce, by a single cleavage, [Leu] enkephalin or [Met] enkephalin from small enkephalin-containing peptides, (Camargo et al., 1987, J. Neurochem. 48, 1258-1263).(ABSTRACT TRUNCATED AT 250 WORDS)

  18. An aspartic protease of the scabies mite Sarcoptes scabiei is involved in the digestion of host skin and blood macromolecules.

    Directory of Open Access Journals (Sweden)

    Wajahat Mahmood

    2013-11-01

    Full Text Available BACKGROUND: Scabies is a disease of worldwide significance, causing considerable morbidity in both humans and other animals. The scabies mite Sarcoptes scabiei burrows into the skin of its host, obtaining nutrition from host skin and blood. Aspartic proteases mediate a range of diverse and essential physiological functions such as tissue invasion and migration, digestion, moulting and reproduction in a number of parasitic organisms. We investigated whether aspartic proteases may play role in scabies mite digestive processes. METHODOLOGY/PRINCIPLE FINDINGS: We demonstrated the presence of aspartic protease activity in whole scabies mite extract. We then identified a scabies mite aspartic protease gene sequence and produced recombinant active enzyme. The recombinant scabies mite aspartic protease was capable of digesting human haemoglobin, serum albumin, fibrinogen and fibronectin, but not collagen III or laminin. This is consistent with the location of the scabies mites in the upper epidermis of human skin. CONCLUSIONS/SIGNIFICANCE: The development of novel therapeutics for scabies is of increasing importance given the evidence of emerging resistance to current treatments. We have shown that a scabies mite aspartic protease plays a role in the digestion of host skin and serum molecules, raising the possibility that interference with the function of the enzyme may impact on mite survival.

  19. Antagonistic peptide technology for functional dissection of CLE peptides revisited.

    Science.gov (United States)

    Czyzewicz, Nathan; Wildhagen, Mari; Cattaneo, Pietro; Stahl, Yvonne; Pinto, Karine Gustavo; Aalen, Reidunn B; Butenko, Melinka A; Simon, Rüdiger; Hardtke, Christian S; De Smet, Ive

    2015-08-01

    In the Arabidopsis thaliana genome, over 1000 putative genes encoding small, presumably secreted, signalling peptides can be recognized. However, a major obstacle in identifying the function of genes encoding small signalling peptides is the limited number of available loss-of-function mutants. To overcome this, a promising new tool, antagonistic peptide technology, was recently developed. Here, this antagonistic peptide technology was tested on selected CLE peptides and the related IDA peptide and its usefulness in the context of studies of peptide function discussed. Based on the analyses, it was concluded that the antagonistic peptide approach is not the ultimate means to overcome redundancy or lack of loss-of-function lines. However, information collected using antagonistic peptide approaches (in the broad sense) can be very useful, but these approaches do not work in all cases and require a deep insight on the interaction between the ligand and its receptor to be successful. This, as well as peptide ligand structure considerations, should be taken into account before ordering a wide range of synthetic peptide variants and/or generating transgenic plants. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. Des-Aspartate-Angiotensin I Attenuates Mortality of Mice Exposed to Gamma Radiation via a Novel Mechanism of Action.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available ACE inhibitors and ARBs (angiotensin receptor blockers have been shown to attenuate radiation injuries in animal models of lethal gamma irradiation. These two classes of drug act by curtailing the actions of angiotensin II-linked inflammatory pathways that are up-regulated during gamma radiation in organ systems such as the brain, lung, kidney, and bone marrow. ACE inhibitors inhibit ACE and attenuate the formation of angiotensin II from angiotensin I; ARBs block the angiotensin AT1 receptor and attenuate the actions of angiotensin II that are elicited through the receptor. DAA-I (des-aspartate-angiotensin I, an orally active angiotensin peptide, also attenuates the deleterious actions of angiotensin II. It acts as an agonist on the angiotensin AT1 receptor and elicits responses that oppose those of angiotensn II. Thus, DAA-I was investigated for its anticipated radioprotection in gamma irradiated mice. DAA-I administered orally at 800 nmole/kg/day for 30 days post exposure (6.4 Gy attenuated the death of mice during the 30-day period. The attenuation was blocked by losartan (50 nmole/kg/day, i.p. that was administered sequential to DAA-I administration. This shows that the radioprotection was mediated via the angiotensin AT1 receptor. Furthermore, the radioprotection correlated to an increase in circulating PGE2 of surviving animals, and this suggests that PGE2 is involved in the radioprotection in DAA-I-treated mice. At the hematopoietic level, DAA-I significantly improved two syndromes of myelosuppression (leucopenia and lymphocytopenia, and mice pre-treated with DAA-I prior to gamma irradiation showed significant improvement in the four myelodysplastic syndromes that were investigated, namely leucopenia, lymphocytopenia, monocytopenia and thrombocytopenia. Based on the known ability of PGE2 to attenuate the loss of functional hematopoietic stem and progenitor cells in radiation injury, we hypothesize that PGE2 mediated the action of DAA

  1. Enhanced cellular adhesion on titanium by silk functionalized with titanium binding and RGD peptides.

    Science.gov (United States)

    Vidal, Guillaume; Blanchi, Thomas; Mieszawska, Aneta J; Calabrese, Rossella; Rossi, Claire; Vigneron, Pascale; Duval, Jean-Luc; Kaplan, David L; Egles, Christophe

    2013-01-01

    Soft tissue adhesion on titanium represents a challenge for implantable materials. In order to improve adhesion at the cell/material interface we used a new approach based on the molecular recognition of titanium by specific peptides. Silk fibroin protein was chemically grafted with titanium binding peptide (TiBP) to increase adsorption of these chimeric proteins to the metal surface. A quartz crystal microbalance was used to quantify the specific adsorption of TiBP-functionalized silk and an increase in protein deposition by more than 35% was demonstrated due to the presence of the binding peptide. A silk protein grafted with TiBP and fibronectin-derived arginine-glycine-aspartic acid (RGD) peptide was then prepared. The adherence of fibroblasts on the titanium surface modified with the multifunctional silk coating demonstrated an increase in the number of adhering cells by 60%. The improved adhesion was demonstrated by scanning electron microscopy and immunocytochemical staining of focal contact points. Chick embryo organotypic culture also revealed strong adhesion of endothelial cells expanding on the multifunctional silk peptide coating. These results demonstrated that silk functionalized with TiBP and RGD represents a promising approach to modify cell-biomaterial interfaces, opening new perspectives for implantable medical devices, especially when reendothelialization is required. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    Science.gov (United States)

    Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won; Lim, Yun Kyong; Kook, Joong-Ki; Cho, Dong-Lyun; Kim, Byung Hoon

    2010-11-01

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH2 of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  3. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of); Lim, Yun Kyong; Kook, Joong-Ki [Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Cho, Dong-Lyun [School of Applied Chemical Engineering and Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju (Korea, Republic of); Kim, Byung Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of)

    2010-11-01

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH{sub 2} of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  4. Radiolabelled peptides for oncological diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)

    2012-02-15

    Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)

  5. Multidimensional Design of Anticancer Peptides.

    Science.gov (United States)

    Lin, Yen-Chu; Lim, Yi Fan; Russo, Erica; Schneider, Petra; Bolliger, Lea; Edenharter, Adriana; Altmann, Karl-Heinz; Halin, Cornelia; Hiss, Jan A; Schneider, Gisbert

    2015-08-24

    The computer-assisted design and optimization of peptides with selective cancer cell killing activity was achieved through merging the features of anticancer peptides, cell-penetrating peptides, and tumor-homing peptides. Machine-learning classifiers identified candidate peptides that possess the predicted properties. Starting from a template amino acid sequence, peptide cytotoxicity against a range of cancer cell lines was systematically optimized while minimizing the effects on primary human endothelial cells. The computer-generated sequences featured improved cancer-cell penetration, induced cancer-cell apoptosis, and were enabled a decrease in the cytotoxic concentration of co-administered chemotherapeutic agents in vitro. This study demonstrates the potential of multidimensional machine-learning methods for rapidly obtaining peptides with the desired cellular activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Roles of Intramolecular and Intermolecular Hydrogen Bonding in a Three-Water-Assisted Mechanism of Succinimide Formation from Aspartic Acid Residues

    Directory of Open Access Journals (Sweden)

    Ohgi Takahashi

    2014-08-01

    Full Text Available Aspartic acid (Asp residues in peptides and proteins are prone to isomerization to the β-form and racemization via a five-membered succinimide intermediate. These nonenzymatic reactions have relevance to aging and age-related diseases. In this paper, we report a three water molecule-assisted, six-step mechanism for the formation of succinimide from Asp residues found by density functional theory calculations. The first two steps constitute a stepwise iminolization of the C-terminal amide group. This iminolization involves a quintuple proton transfer along intramolecular and intermolecular hydrogen bonds formed by the C-terminal amide group, the side-chain carboxyl group, and the three water molecules. After a conformational change (which breaks the intramolecular hydrogen bond involving the iminol nitrogen and a reorganization of water molecules, the iminol nitrogen nucleophilically attacks the carboxyl carbon of the Asp side chain to form a five-membered ring. This cyclization is accompanied by a triple proton transfer involving two water molecules, so that a gem-diol tetrahedral intermediate is formed. The last step is dehydration of the gem-diol group catalyzed by one water molecule, and this is the rate-determining step. The calculated overall activation barrier (26.7 kcal mol−1 agrees well with an experimental activation energy.

  7. Antiadhesive polymer brush coating functionalized with antimicrobial and RGD peptides to reduce biofilm formation and enhance tissue integration.

    Science.gov (United States)

    Muszanska, Agnieszka K; Rochford, Edward T J; Gruszka, Agnieszka; Bastian, Andreas A; Busscher, Henk J; Norde, Willem; van der Mei, Henny C; Herrmann, Andreas

    2014-06-09

    This paper describes the synthesis and characterization of polymer-peptide conjugates to be used as infection-resistant coating for biomaterial implants and devices. Antiadhesive polymer brushes composed of block copolymer Pluronic F-127 (PF127) were functionalized with antimicrobial peptides (AMP), able to kill bacteria on contact, and arginine-glycine-aspartate (RGD) peptides to promote the adhesion and spreading of host tissue cells. The antiadhesive and antibacterial properties of the coating were investigated with three bacterial strains: Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa. The ability of the coating to support mammalian cell growth was determined using human fibroblast cells. Coatings composed of the appropriate ratio of the functional components: PF127, PF127 modified with AMP, and PF127 modified with RGD showed good antiadhesive and bactericidal properties without hampering tissue compatibility.

  8. Distribution and evolution of the serine/aspartate racemase family in invertebrates.

    Science.gov (United States)

    Uda, Kouji; Abe, Keita; Dehara, Yoko; Mizobata, Kiriko; Sogawa, Natsumi; Akagi, Yuki; Saigan, Mai; Radkov, Atanas D; Moe, Luke A

    2016-02-01

    Free D-amino acids have been found in various invertebrate phyla, while amino acid racemase genes have been identified in few species. The purpose of this study is to elucidate the distribution, function, and evolution of amino acid racemases in invertebrate animals. We searched the GenBank databases, and found 11 homologous serine racemase genes from eight species in eight different invertebrate phyla. The cloned genes were identified based on their maximum activity as Acropora millepora (Cnidaria) serine racemase (SerR) and aspartate racemase (AspR), Caenorhabditis elegans (Nematoda) SerR, Capitella teleta (Annelida) SerR, Crassostrea gigas (Mollusca) SerR and AspR, Dugesia japonica (Platyhelminthes) SerR, Milnesium tardigradum (Tardigrada) SerR, Penaeus monodon (Arthropoda) SerR and AspR and Strongylocentrotus purpuratus (Echinodermata) AspR. We found that Acropora, Aplysia, Capitella, Crassostrea and Penaeus had two amino acid racemase paralogous genes and these paralogous genes have evolved independently by gene duplication at their recent ancestral species. The transcriptome analyses using available SRA data and enzyme kinetic data suggested that these paralogous genes are expressed in different tissues and have different functions in vivo. Phylogenetic analyses clearly indicated that animal SerR and AspR are not separated by their particular racemase functions and form a serine/aspartate racemase family cluster. Our results revealed that SerR and AspR are more widely distributed among invertebrates than previously known. Moreover, we propose that the triple serine loop motif at amino acid positions 150-152 may be responsible for the large aspartate racemase activity and the AspR evolution from SerR.

  9. Structural Insights into a Novel Class of Aspartate Aminotransferase from Corynebacterium glutamicum.

    Directory of Open Access Journals (Sweden)

    Hyeoncheol Francis Son

    Full Text Available Aspartate aminotransferase from Corynebacterium glutamicum (CgAspAT is a PLP-dependent enzyme that catalyzes the production of L-aspartate and α-ketoglutarate from L-glutamate and oxaloacetate in L-lysine biosynthesis. In order to understand the molecular mechanism of CgAspAT and compare it with those of other aspartate aminotransferases (AspATs from the aminotransferase class I, we determined the crystal structure of CgAspAT. CgAspAT functions as a dimer, and the CgAspAT monomer consists of two domains, the core domain and the auxiliary domain. The PLP cofactor is found to be bound to CgAspAT and stabilized through unique residues. In our current structure, a citrate molecule is bound at the active site of one molecule and mimics binding of the glutamate substrate. The residues involved in binding of the PLP cofactor and the glutamate substrate were confirmed by site-directed mutagenesis. Interestingly, compared with other AspATs from aminotransferase subgroup Ia and Ib, CgAspAT exhibited unique binding sites for both cofactor and substrate; moreover, it was found to have unusual structural features in the auxiliary domain. Based on these structural differences, we propose that CgAspAT does not belong to either subgroup Ia or Ib, and can be categorized into a subgroup Ic. The phylogenetic tree and RMSD analysis also indicates that CgAspAT is located in an independent AspAT subgroup.

  10. Aspartic acid-promoted highly selective and sensitive colorimetric sensing of cysteine in rat brain.

    Science.gov (United States)

    Qian, Qin; Deng, Jingjing; Wang, Dalei; Yang, Lifen; Yu, Ping; Mao, Lanqun

    2012-11-06

    Direct selective determination of cysteine in the cerebral system is of great importance because of the crucial roles of cysteine in physiological and pathological processes. In this study, we report a sensitive and selective colorimetric assay for cysteine in the rat brain with gold nanoparticles (Au-NPs) as the signal readout. Initially, Au-NPs synthesized with citrate as the stabilizer are red in color and exhibit absorption at 520 nm. The addition of an aqueous solution (20 μL) of cysteine or aspartic acid alone to a 200 μL Au-NP dispersion causes no aggregation, while the addition of an aqueous solution of cysteine into a Au-NP dispersion containing aspartic acid (1.8 mM) causes the aggregation of Au-NPs and thus results in the color change of the colloid from wine red to blue. These changes are ascribed to the ion pair interaction between aspartic acid and cysteine on the interface between Au-NPs and solution. The concentration of cysteine can be visualized with the naked eye and determined by UV-vis spectroscopy. The signal output shows a linear relationship for cysteine within the concentration range from 0.166 to 1.67 μM with a detection limit of 100 nM. The assay demonstrated here is highly selective and is free from the interference of other natural amino acids and other thiol-containing species as well as the species commonly existing in the brain such as lactate, ascorbic acid, and glucose. The basal dialysate level of cysteine in the microdialysate from the striatum of adult male Sprague-Dawley rats is determined to be around 9.6 ± 2.1 μM. The method demonstrated here is facile but reliable and durable and is envisaged to be applicable to understanding the chemical essence involved in physiological and pathological events associated with cysteine.

  11. Insulin aspart in patients with gestational diabetes mellitus and pregestational diabetes mellitus

    Directory of Open Access Journals (Sweden)

    M C Deepaklal

    2015-01-01

    Full Text Available Aims: This study was undertaken to assess the effectiveness and safety of insulin aspart in patients with gestational and pregestational diabetes. Settings and Design: An open-label, prospective, nonrandomized, comparative, and observational study conducted at single center in India. Subjects and Methods: A total of 276 patients were in gestational diabetes mellitus (GDM group, 79 were in the pre-GDM group. Patients were started on insulin therapy (insulin aspart ± neutral protamine hagedorn once medical nutrition therapy for 2 weeks failed to achieve control, that is., fasting plasma glucose ≥90 mg/dL and/or 1.0 h postprandial plasma glucose ≥130 mg/dL. Insulin dose was titrated to keep the blood glucose values between 90 and 130 mg/dL. Patients were followed once every 4 weeks until the 28 th week, then once every 2 weeks until 32 nd week, then once every week until delivery, and the final visit was on 60 ± 7 days. The final outcome was assessed in terms of incidence of macrosomia (>3.5 kg body weight between the two groups and episodes of confirmed (blood glucose <56 mg/dL minor or major maternal hypoglycemia. Results: There was no statistically significant difference among the two groups in terms of incidence of macrosomia that is., it was 5.1%, 8.9% in GDM, pre-GDM group, respectively. Conclusions: Insulin aspart was found safe in pregnancy, however, more studies with double-blind, standard controlled studies are required to confirm the findings of this study.

  12. Structure of the Catalytic Trimer of Methanococcus jannaschii Aspartate Transcarbamoylase in an Orthorhombic Crystal Form

    Energy Technology Data Exchange (ETDEWEB)

    Vitali,J.; Colaneri, M.

    2008-01-01

    Crystals of the catalytic subunit of Methanococcus jannaschii aspartate transcarbamoylase in an orthorhombic crystal form contain four crystallographically independent trimers which associate in pairs to form stable staggered complexes that are similar to each other and to a previously determined monoclinic C2 form. Each subunit has a sulfate in the central channel. The catalytic subunits in these complexes show flexibility, with the elbow angles of the monomers differing by up to 7.4 between crystal forms. Moreover, there is also flexibility in the relative orientation of the trimers around their threefold axis in the complexes, with a difference of 4 between crystal forms.

  13. A Concise Synthesis of Glycolipids Based on Aspartic Acid Building Blocks

    Directory of Open Access Journals (Sweden)

    Lorna Abbey

    2012-09-01

    Full Text Available L-Aspartic acid building blocks bearing galactosyl moieties were used to synthesise glycolipid mimetics of variable hydrocarbon chain length. The glycolipids were readily prepared through amide bond formation using the TBTU/HOBt coupling methodology. It was observed that, under these conditions, activation of the α-carboxylic acid of the intermediates led to near complete racemisation of the chiral centre if the reaction was carried out in the presence of a base such as triethylamine. The enantiomerically pure glycolipids were obtained after careful consideration of the synthetic sequence and by performing the coupling reactions in the absence of base.

  14. N-Hydroxypyrazolyl glycine derivatives as selective N-methyl-D-aspartic acid receptor ligands

    DEFF Research Database (Denmark)

    Clausen, Rasmus Prætorius; Christensen, Caspar; Hansen, Kasper Bø

    2008-01-01

    glycine (NHP5G) derivatives are selectively recognized by N-methyl- d-aspartic acid (NMDA) receptors and that the ( R)-enantiomers are preferred. Moreover, several of the compounds are able to discriminate between individual subtypes among the NMDA receptors, providing new pharmacological tools....... For example, 4-propyl NHP5G is an antagonist at the NR1/NR2A subtype but an agonist at the NR1/NR2D subtype. Molecular docking studies indicate that the substituent protrudes into a region that may be further exploited to improve subtype selectivity, thereby opening up a design strategy for ligands which can...

  15. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  16. Antimicrobial peptides in annelids

    OpenAIRE

    Tasiemski, A.

    2008-01-01

    Gene encoded antimicrobial peptides (AMPs) are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the ch...

  17. Zinc aspartate suppresses T cell activation in vitro and relapsing experimental autoimmune encephalomyelitis in SJL/J mice.

    Science.gov (United States)

    Stoye, Diana; Schubert, Claudia; Goihl, Alexander; Guttek, Karina; Reinhold, Annegret; Brocke, Stefan; Grüngreiff, Kurt; Reinhold, Dirk

    2012-06-01

    Zinc is an essential trace element with a critical role in normal growth and development and in immune homeostasis. Zinc deficiency impairs both the innate and the adaptive immune system and can be normalized by zinc supplementation. On the other end of the spectrum, high dosages of zinc diminish immune cell functions similar to zinc deficiency. Here, we investigated the influence of zinc aspartate on proliferation and cytokine production of stimulated human T cells and mouse splenocytes in vitro. Furthermore, the effect of zinc aspartate was examined in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of Multiple Sclerosis (MS) with a Th1/Th17 T cell-mediated immunopathogenesis. Zinc aspartate suppressed proliferation as well as IL-2, IL-10 and IL-17 production in stimulated human T cells and mouse splenocytes. Importantly, administration of a medium range dose of 30 μg/day zinc aspartate [1.5 mg/kg body weight (BW)] in a therapeutic manner led to a significant reduction of the clinical severity of the EAE during the first relapse of the disease. A lower zinc aspartate dose (6 μg/day, 0.3 mg/kg BW) had no significant therapeutic effect on the severity of the EAE, while administration of higher zinc aspartate amounts (120 μg/day, 6 mg/kg BW) led to more severe disease. Taken together, our data suggest that zinc aspartate can modulate activation, proliferation and cytokine production of effector T cells in vitro and in vivo and that activated autoreactive T cells may be potential therapeutic targets of tightly controlled zinc supplementation in autoimmune diseases like MS.

  18. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Andhra Pradesh cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Mohammed Abubaker

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Andhra Pradesh, India. Results: A total of 3077 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 2452, insulin detemir (n = 308, insulin aspart (n = 226, basal insulin plus insulin aspart (n = 21 and other insulin combinations (n = 68. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 8.9% and insulin user (mean HbA 1 c: 9.2% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −1.2%, insulin users: −1.1%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  19. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the North India cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Surender Kumar

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from North India. Results: A total of 4912 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Patients had started on or were switched to biphasic insulin aspart (n = 3619, insulin detemir (n = 880, insulin aspart (n = 331, basal insulin plus insulin aspart (n = 37 and other insulin combinations (n = 44. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.8% and insulin user (mean HbA 1 c: 9.8% groups. After 24 weeks of treatment, both the study groups showed improvement in HbA 1 c (insulin naïve: −2.7%, insulin users: −2.6%. SADRs including major hypoglycaemic events or episodes did not occur in any of the study patients. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  20. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Eastern Saudi Arabia cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Faisal Hashim

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Eastern Saudi Arabia. Results: A total of 1040 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 489, insulin detemir (n = 360, insulin aspart (n = 37, basal insulin plus insulin aspart (n = 96 and other insulin combinations (n = 57. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.0% and insulin user (mean HbA 1 c: 9.2% groups. After 24 weeks of treatment, both the groups showed improvement in HbA 1 c (insulin naïve: −2.7%, insulin users: −1.7%. No major hypoglycaemic episodes were observed at 24 weeks. SADR was reported in 0.6% of insulin users. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  1. Clinical experience with insulin detemir type 2 diabetes mellitus, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Rabat-Sale-Zemmour-Zaer Region cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Abdelmjid Chraibi

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66 726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Rabat-Sale-Zemmour-Zaer region, Morocco. Results: A total of 424 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 177, insulin detemir (n = 150, insulin aspart (n = 11, basal insulin plus insulin aspart (n = 45 and other insulin combinations (n = 41. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 10.1% and insulin user (mean HbA 1 c: 9.4% groups. After 24 weeks of treatment, all the study groups showed improvement in HbA 1 c (insulin naïve: −2.5%, insulin users: −1.8%. Major hypoglycaemia was observed in the insulin user group after 24 weeks (0.1 events/patient-year. SADRs were reported in 0.5% of insulin users. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  2. Functional Divergence of Poplar Histidine-Aspartate Kinase HK1 Paralogs in Response to Osmotic Stress

    Directory of Open Access Journals (Sweden)

    François Héricourt

    2016-12-01

    Full Text Available Previous works have shown the existence of protein partnerships belonging to a MultiStep Phosphorelay (MSP in Populus putatively involved in osmosensing. This study is focused on the identification of a histidine-aspartate kinase, HK1b, paralog of HK1a. The characterization of HK1b showed its ability to homo- and hetero-dimerize and to interact with a few Histidine-containing Phosphotransfer (HPt proteins, suggesting a preferential partnership in poplar MSP linked to drought perception. Furthermore, determinants for interaction specificity between HK1a/1b and HPts were studied by mutagenesis analysis, identifying amino acids involved in this specificity. The HK1b expression analysis in different poplar organs revealed its co-expression with three HPts, reinforcing the hypothesis of partnership participation in the MSP in planta. Moreover, HK1b was shown to act as an osmosensor with kinase activity in a functional complementation assay of an osmosensor deficient yeast strain. These results revealed that HK1b showed a different behaviour for canonical phosphorylation of histidine and aspartate residues. These phosphorylation modularities of canonical amino acids could explain the improved osmosensor performances observed in yeast. As conserved duplicates reflect the selective pressures imposed by the environmental requirements on the species, our results emphasize the importance of HK1 gene duplication in poplar adaptation to drought stress.

  3. Molecular Mechanisms Elicited by d-Aspartate in Leydig Cells and Spermatogonia.

    Science.gov (United States)

    Di Fiore, Maria Maddalena; Santillo, Alessandra; Falvo, Sara; Longobardi, Salvatore; Chieffi Baccari, Gabriella

    2016-07-14

    A bulk of evidence suggests that d-aspartate (d-Asp) regulates steroidogenesis and spermatogenesis in vertebrate testes. This review article focuses on intracellular signaling mechanisms elicited by d-Asp possibly via binding to the N-methyl-d-aspartate receptor (NMDAR) in both Leydig cells, and spermatogonia. In Leydig cells, the amino acid upregulates androgen production by eliciting the adenylate cyclase-cAMP and/or mitogen-activated protein kinase (MAPK) pathways. d-Asp treatment enhances gene and protein expression of enzymes involved in the steroidogenic cascade. d-Asp also directly affects spermatogonial mitotic activity. In spermatogonial GC-1 cells, d-Asp induces phosphorylation of MAPK and AKT serine-threonine kinase proteins, and stimulates expression of proliferating cell nuclear antigen (PCNA) and aurora kinase B (AURKB). Further stimulation of spermatogonial GC-1 cell proliferation might come from estradiol/estrogen receptor β (ESR2) interaction. d-Asp modulates androgen and estrogen levels as well as the expression of their receptors in the rat epididymis by acting on mRNA levels of Srd5a1 and Cyp19a1 enzymes, hence suggesting involvement in spermatozoa maturation.

  4. Molecular Mechanisms Elicited by d-Aspartate in Leydig Cells and Spermatogonia

    Directory of Open Access Journals (Sweden)

    Maria Maddalena Di Fiore

    2016-07-01

    Full Text Available A bulk of evidence suggests that d-aspartate (d-Asp regulates steroidogenesis and spermatogenesis in vertebrate testes. This review article focuses on intracellular signaling mechanisms elicited by d-Asp possibly via binding to the N-methyl-d-aspartate receptor (NMDAR in both Leydig cells, and spermatogonia. In Leydig cells, the amino acid upregulates androgen production by eliciting the adenylate cyclase-cAMP and/or mitogen-activated protein kinase (MAPK pathways. d-Asp treatment enhances gene and protein expression of enzymes involved in the steroidogenic cascade. d-Asp also directly affects spermatogonial mitotic activity. In spermatogonial GC-1 cells, d-Asp induces phosphorylation of MAPK and AKT serine-threonine kinase proteins, and stimulates expression of proliferating cell nuclear antigen (PCNA and aurora kinase B (AURKB. Further stimulation of spermatogonial GC-1 cell proliferation might come from estradiol/estrogen receptor β (ESR2 interaction. d-Asp modulates androgen and estrogen levels as well as the expression of their receptors in the rat epididymis by acting on mRNA levels of Srd5a1 and Cyp19a1 enzymes, hence suggesting involvement in spermatozoa maturation.

  5. D-Aspartate Induces Proliferative Pathways in Spermatogonial GC-1 Cells.

    Science.gov (United States)

    Santillo, Alessandra; Falvo, Sara; Chieffi, Paolo; Di Fiore, Maria Maddalena; Senese, Rosalba; Chieffi Baccari, Gabriella

    2016-02-01

    D-aspartate (D-Asp) is an endogenous amino acid present in vertebrate tissues, with particularly high levels in the testis. In vivo studies indicate that D-Asp indirectly stimulates spermatogenesis through the hypothalamic-pituitary-gonadal axis. Moreover, in vitro studies have demonstrated that D-Asp up-regulates testosterone production in Leydig cells by enhancing expression of the steroidogenic acute regulatory protein. In this study, a cell line derived from immortalized type-B mouse spermatogonia retaining markers of mitotic germ cells (GC-1) was employed to explore more direct involvement of D-Asp in spermatogenesis. Activity and protein expression of markers of cell proliferation were determined at intervals during incubation in D-Asp-containing medium. D-Asp induced phosphorylation of ERK and Akt proteins, stimulated expression of PCNA and Aurora B, and enhanced mRNA synthesis and protein expression of P450 aromatase and protein expression of Estrogen Receptor β (ERβ). These results are the first demonstration of a direct effect of D-Asp on spermatogonial mitotic activity. Considering that spermatogonia express the NR1 subunit of the N-Methyl-D-Aspartic Acid receptor (NMDAR), we suggest that their response to D-Asp depends on NMDAR-mediated activation of the ERK and Akt pathways and is further enhanced by activation of the P450 aromatase/ERβ pathway. © 2015 Wiley Periodicals, Inc.

  6. Design and optimization of aspartate N-acetyltransferase inhibitors for the potential treatment of Canavan disease.

    Science.gov (United States)

    Thangavelu, Bharani; Mutthamsetty, Vinay; Wang, Qinzhe; Viola, Ronald E

    2017-02-01

    Canavan disease is a fatal neurological disorder caused by defects in the metabolism of N-acetyl-l-aspartate (NAA). Recent work has shown that the devastating symptoms of this disorder are correlated with the elevated levels of NAA observed in these patients, caused as a consequence of the inability of mutated forms of aspartoacylase to adequately catalyze its breakdown. The membrane-associated enzyme responsible for the synthesis of NAA, aspartate N-acetyltransferase (ANAT), has recently been purified and examined (Wang et al., Prot Expr Purif. 2016;119:11). With the availability, for the first time, of a stable and soluble form of ANAT we can now report the identification of initial inhibitors against this biosynthetic enzyme, obtained from the screening of several focused compound libraries. Two core structures of these moderate binding compounds have subsequently been optimized, with the most potent inhibitors in these series possessing sub-micromolar inhibition constants (Ki values) against ANAT. Slowing the production of NAA via the inhibition of ANAT will lower the elevated levels of this metabolite and can potentially serve as a treatment option to moderate the symptoms of Canavan disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Arabidopsis aspartic proteases A36 and A39 play roles in plant reproduction.

    Science.gov (United States)

    Gao, Hui; Li, Rui; Guo, Yi

    2017-04-03

    Aspartic proteases (Aps, EC3.4.23) are one of the 4 major mechanistic classes of proteolytic enzymes with the conserved motifs Asp-Thr/Ser-Gly (DT/SG) at the active site and are activated at acidic pH. In Arabidopsis, 69 genes were identified as coding putative aspartic proteinases. However, little is known about most of these enzymes. Recently, we characterized 2 novel Arabidopsis Aps genes, A36 and A39, which encode 2 putative GPI-anchored pollen-high-expressed Aps. a36 a39 mutants display significant abortion. The pollen grains underwent apoptosis-like programmed cell death and the degeneration of female gametes was also appeared in the a36 a39 mutant. Besides, the pollen tube of a36 a39 has compromised micropylar guidance. A36 and A39 were membrane-anchored protein and co-localized with a reported GPI-anchored protein COBRA-LIKE 10 (COBL10). In apical region of a36 a39 pollen tubes cell wall, the abundance of highly methlyestered homogalacturonans and xyloglucans were significantly increased. These results indicated that A36 and A39 are vital factors involved in gametogenesis and pollen guidance in Arabidopsis.

  8. Study of the n-methyl-d-aspartate antagonistic properties of anticholinergic drugs

    Energy Technology Data Exchange (ETDEWEB)

    McDonough, J.H.; Shih, T.M.

    1995-12-31

    A study of the N-methyl-D-aspartate antagonistic properties of anticholinergic drugs. PHARMACOL BIOCHEM BEHAV. 51(2/3) 249-253, 1995. Drugs that act at the N-methyl-D-aspartate (NMDA) receptor complex have the ability to terminate nerve agent-induced seizures and modulate the neuropathologic consequences of agent exposure. Drugs with mixed anticholinergic and anti-NMDA properties potentially provide an ideal class of compounds for development as anticonvulsant treatments for nerve agent casualties. The present experiment evaluated the potential NMDA antagonist activity of 11 anticholinergic drugs by determining whether pretreatment with the compound was capable of protecting mice from the lethal effects of NMDA. The following anticholinergic drugs antagonized NMDA lethality and are ranked according to their potency: mecamylamine > procyclidine = benactyzine > biperiden > tribexyphenidyl. The anticholinergics atropine, aprophen, azaprophen, benztropine, 3-quinudidinyl benzilate (QNB), and scopolamine failed to show NMDA antagonist properties. In addition, and unexpectedly, diazepam, ethanol, and pentobarbital were also shown to be capable of antagonizing NMDA lethality over a certain range of doses. The advantages and limitations of using antagonism of NMDA lethality in mice as a bioassay for determining the NMDA antagonist properties of drugs are also discussed.

  9. The Role of N-Methyl D-Aspartate Receptors on Pain Transmission

    Directory of Open Access Journals (Sweden)

    Yasemin Gunes

    2012-02-01

    Full Text Available Aim : In the experimental studies, NMDA (N-methyl-D-aspartate receptors play important role in the mechanism of action among the drugs used for the treatment of pain. The NMDA receptors in the dorsal horn of spinal cord is essential for central sensitization and the central facilitation of pain transmission produced by peripheral injury. The aim of this study was to evaluate the contributions of peripheral NMDA receptor agonist and antagonists in peripheral pain transmission. Material-Method : In the present study, N methyl aspartic acid (NMDA and antagonist ( MK-801 were administered intraplantarily to investigate withdrawal effects, the dose and time dependent latency using thermal plantar test method in rats. Results : MK-801 caused dose-dependent thermal anti-nociceptive effects, whereas NMDA led to reduction in the thermal nociceptive latency and hyperalgesia. Conclusion : Peripheral NMDA receptors may play a dominant role in the transmission of pain information. [Cukurova Med J 2012; 37(1.000: 9-16

  10. Renin inhibition by substituted piperidines: a novel paradigm for the inhibition of monomeric aspartic proteinases?

    Science.gov (United States)

    Oefner, C; Binggeli, A; Breu, V; Bur, D; Clozel, J P; D'Arcy, A; Dorn, A; Fischli, W; Grüninger, F; Güller, R; Hirth, G; Märki, H; Mathews, S; M ller, M; Ridley, R G; Stadler, H; Vieira, E; Wilhelm, M; Winkler, F; Wostl, W

    1999-03-01

    The aspartic proteinase renin catalyses the first and rate-limiting step in the conversion of angiotensinogen to the hormone angiotensin II, and therefore plays an important physiological role in the regulation of blood pressure. Numerous potent peptidomimetic inhibitors of this important drug target have been developed, but none of these compounds have progressed past clinical phase II trials. Limited oral bioavailability or excessive production costs have prevented these inhibitors from becoming new antihypertensive drugs. We were interested in developing new nonpeptidomimetic renin inhibitors. High-throughput screening of the Roche compound library identified a simple 3, 4-disubstituted piperidine lead compound. We determined the crystal structures of recombinant human renin complexed with two representatives of this new class. Binding of these substituted piperidine derivatives is accompanied by major induced-fit adaptations around the enzyme's active site. The efficient optimisation of the piperidine inhibitors was facilitated by structural analysis of the renin active site in two renin-inhibitor complexes (some of the piperidine derivatives have picomolar affinities for renin). These structural changes provide the basis for a novel paradigm for inhibition of monomeric aspartic proteinases.

  11. Nanostructured aluminium oxide powders obtained by aspartic acid-nitrate gel-combustion routes

    Energy Technology Data Exchange (ETDEWEB)

    Gardey Merino, Maria Celeste, E-mail: mcgardey@frm.utn.edu.a [Laboratorio de Investigaciones y Servicios Ambientales Mendoza (LISAMEN) - CCT - CONICET, Avda. Ruiz Leal s/n, Parque Gral. San Martin, (M5502IRA) Ciudad de Mendoza, Prov. de Mendoza (Argentina); Grupo CLIOPE, Universidad Tecnologica Nacional - Facultad Regional Mendoza, Rodriguez 273, (M5502AJE) Ciudad de Mendoza, Prov. de Mendoza (Argentina); Lascalea, Gustavo E. [Laboratorio de Investigaciones y Servicios Ambientales Mendoza (LISAMEN) - CCT - CONICET, Avda. Ruiz Leal s/n, Parque Gral. San Martin, (M5502IRA) Ciudad de Mendoza, Prov. de Mendoza (Argentina); Sanchez, Laura M. [CINSO (Centro de Investigaciones en Solidos), CITEFA - CONICET, J.B. de La Salle 4397, (B1603ALO) Villa Martelli, Prov. de Buenos Aires (Argentina); Vazquez, Patricia G. [Centro de Investigacion y Desarrollo en Ciencias Aplicadas ' Dr. Jorge J. Ronco' (CINDECA), CONICET, Universidad Nacional de La Plata, Calle 47 nro. 257, (B1900AJK) La Plata, Prov. de Buenos Aires (Argentina); Cabanillas, Edgardo D. [CONICET and Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Gral. Paz 1499, (1650) San Martin, Prov. de Buenos Aires (Argentina); Lamas, Diego G. [CINSO (Centro de Investigaciones en Solidos), CITEFA - CONICET, J.B. de La Salle 4397, (B1603ALO) Villa Martelli, Prov. de Buenos Aires (Argentina)

    2010-04-16

    In this work, two new gel-combustion routes for the synthesis of Al{sub 2}O{sub 3} nanopowders with aspartic acid as fuel are presented. The first route is a conventional stoichiometric process, while the second one is a non-stoichiometric, pH-controlled process. These routes were compared with similar synthesis procedures using glycine as fuel, which are well-known in the literature. The samples were calcined in air at different temperatures, in a range of 600-1200 {sup o}C. They were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and BET specific surface area. Different phases were obtained depending on the calcination temperature: amorphous, {gamma} (metastable) or {alpha} (stable). The amorphous-to-{gamma} transition was found for calcination temperatures in the range of 700-900 {sup o}C, while the {gamma}-to-{alpha} one was observed for calcination temperatures of 1100-1200 {sup o}C. The retention of the metastable {gamma} phase is probably due to a crystallite size effect. It transforms to the {alpha} phase after the crystallite size increases over a critical size during the calcination process at 1200 {sup o}C. The highest BET specific surface areas were obtained for both nitrate-aspartic acid routes proposed in this work, reaching values of about 50 m{sup 2}/g.

  12. Peptide-enhanced oral delivery of therapeutic peptides and proteins

    DEFF Research Database (Denmark)

    Kristensen, Mie; Foged, Camilla; Berthelsen, Jens

    2013-01-01

    Systemic therapy upon oral delivery of biologics, such as peptide and protein drugs is limited due to their large molecular size, their low enzymatic stability and their inability to cross the intestinal epithelium. Ways to overcome the epithelial barrier include the use of peptide-based excipients...... throughout the gastrointestinal (GI) tract, chemical stability is an inherent challenge when employing amino acid-based excipients for oral delivery, and multiple approaches have been investigated to improve this. The exact mechanisms of transepithelial translocation are discussed, and it is believed...... for oral delivery of peptide and protein drugs highlighting recent studies and the most promising compounds from these classes of peptide excipients....

  13. Synergistic effects of light-emitting probes and peptides for targeting and monitoring integrin expression.

    Science.gov (United States)

    Achilefu, Samuel; Bloch, Sharon; Markiewicz, Mary A; Zhong, Tuoxiu; Ye, Yunpeng; Dorshow, Richard B; Chance, Britton; Liang, Kexian

    2005-05-31

    Integrins mediate many biological processes, including tumor-induced angiogenesis and metastasis. The arginine-glycine-aspartic acid (RGD) peptide sequence is a common recognition motif by integrins in many proteins and small peptides. While evaluating a small library of RGD peptides for imaging alpha(V)beta(3) integrin (ABI)-positive tumor cell line (A549) by optical methods, we discovered that conjugating a presumably inactive linear hexapeptide GRDSPK with a near-infrared carbocyanine molecular probe (Cypate) yielded a previously undescribed bioactive ligand (Cyp-GRD) that targets ABI-positive tumors. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay with A549 cells showed that Cyp-GRD was not cytotoxic up to 100 muM in cell culture. The compound was internalized by cells, and this internalization was blocked by coincubation with a cyclic RGD peptide (cyclo[RGDfV], f is d-phenylalanine) that binds ABI with high affinity. In vivo, Cyp-GRD selectively accumulated in tumors relative to surrounding normal tissues. Blocking studies with cyclo[RGDfV] inhibited the in vivo uptake of Cyp-GRD, suggesting that both compounds target the same active site of the protein. A strong correlation between the Cyp-GRD peptide and mitochondrial NADH concentration suggests that the new molecule could also report on the metabolic status of cells ex vivo. Interestingly, neither a Cypate-labeled linear RGD peptide nor an (111)In-labeled DOTA-GRD conjugate was selectively retained in the tumor. These results clearly demonstrate the synergistic effects of Cypate and GRD peptide for molecular recognition of integrin expression and suggest the potential of using carbocyanines as optical scaffolds for designing biologically active molecules.

  14. Analysis of the HLA-DR peptidome from human dendritic cells reveals high affinity repertoires and nonconventional pathways of peptide generation.

    Science.gov (United States)

    Ciudad, M Teresa; Sorvillo, Nicoletta; van Alphen, Floris P; Catalán, Diego; Meijer, Alexander B; Voorberg, Jan; Jaraquemada, Dolores

    2017-01-01

    Dendritic cells (DCs) are the major professional APCs of the immune system; however, their MHC-II-associated peptide repertoires have been hard to analyze, mostly because of their scarce presence in blood and tissues. In vitro matured human monocyte-derived DCs (MoDCs) are widely used as professional APCs in experimental systems. In this work, we have applied mass spectrometry to identify the HLA-DR-associated self-peptide repertoires from small numbers of mature MoDCs (∼5 × 106 cells), derived from 7 different donors. Repertoires of 9 different HLA-DR alleles were defined from analysis of 1319 peptides, showing the expected characteristics of MHC-II-associated peptides. Most peptides identified were predicted high binders for their respective allele, formed nested sets, and belonged to endo-lysosomal pathway-degraded proteins. Approximately 20% of the peptides were derived from cytosolic and nuclear proteins, a recurrent finding in HLA-DR peptide repertoires. Of interest, most of these peptides corresponded to single sequences, did not form nested sets, and were located at the C terminus of the parental protein, which suggested alternative processing. Analysis of cleavage patterns for terminal peptides predominantly showed aspartic acid before the cleavage site of both C- and N-terminal peptides and proline immediately after the cleavage site in C-terminal peptides. Proline was also frequent next to the cut sites of internal peptides. These data provide new insights into the Ag processing capabilities of DCs. The relevance of these processing pathways and their contribution to response to infection, tolerance induction, or autoimmunity deserve further analysis. © Society for Leukocyte Biology.

  15. Synthesis of stable C-linked ferrocenyl amino acids and their use in solution-phase peptide synthesis.

    Science.gov (United States)

    Philip, Anijamol T; Chacko, Shibin; Ramapanicker, Ramesh

    2015-12-01

    Incorporation of ferrocenyl group to peptides is an efficient method to alter their hydrophobicity. Ferrocenyl group can also act as an electrochemical probe when incorporated onto functional peptides. Most often, ferrocene is incorporated onto peptides post-synthesis via amide, ester or triazole linkages. Stable amino acids containing ferrocene as a C-linked side chain are potentially useful building units for the synthesis of ferrocene-containing peptides. We report here an efficient route to synthesize ferrocene-containing amino acids that are stable and can be used in peptide synthesis. Coupling of 2-ferrocenyl-1,3-dithiane and iodides derived from aspartic acid or glutamic acid using n-butyllithium leads to the incorporation of a ferrocenyl unit to the δ-position or ε-position of an α-amino acid. The reduction or hydrolysis of the dithiane group yields an alkyl or an oxo derivative. The usability of the synthesized amino acids is demonstrated by incorporating one of the amino acids in both C-terminus and N-terminus of tripeptides in solution phase. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

  16. Solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Jensen, Knud Jørgen

    2013-01-01

    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective.......This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  17. Biodiscovery of aluminum binding peptides

    Science.gov (United States)

    Adams, Bryn L.; Sarkes, Deborah A.; Finch, Amethist S.; Hurley, Margaret M.; Stratis-Cullum, Dimitra

    2013-05-01

    Cell surface peptide display systems are large and diverse libraries of peptides (7-15 amino acids) which are presented by a display scaffold hosted by a phage (virus), bacteria, or yeast cell. This allows the selfsustaining peptide libraries to be rapidly screened for high affinity binders to a given target of interest, and those binders quickly identified. Peptide display systems have traditionally been utilized in conjunction with organic-based targets, such as protein toxins or carbon nanotubes. However, this technology has been expanded for use with inorganic targets, such as metals, for biofabrication, hybrid material assembly and corrosion prevention. While most current peptide display systems employ viruses to host the display scaffold, we have recently shown that a bacterial host, Escherichia coli, displaying peptides in the ubiquitous, membrane protein scaffold eCPX can also provide specific peptide binders to an organic target. We have, for the first time, extended the use of this bacterial peptide display system for the biodiscovery of aluminum binding 15mer peptides. We will present the process of biopanning with macroscopic inorganic targets, binder enrichment, and binder isolation and discovery.

  18. Antitumor Peptides from Marine Organisms

    Directory of Open Access Journals (Sweden)

    Mi Sun

    2011-10-01

    Full Text Available The biodiversity of the marine environment and the associated chemical diversity constitute a practically unlimited resource of new antitumor agents in the field of the development of marine bioactive substances. In this review, the progress on studies of antitumor peptides from marine sources is provided. The biological properties and mechanisms of action of different marine peptides are described; information about their molecular diversity is also presented. Novel peptides that induce apoptosis signal pathway, affect the tubulin-microtubule equilibrium and inhibit angiogenesis are presented in association with their pharmacological properties. It is intended to provide useful information for further research in the fields of marine antitumor peptides.

  19. Improving Peptide Applications Using Nanotechnology.

    Science.gov (United States)

    Narayanaswamy, Radhika; Wang, Tao; Torchilin, Vladimir P

    2016-01-01

    Peptides are being successfully used in various fields including therapy and drug delivery. With advancement in nanotechnology and targeted delivery carrier systems, suitable modification of peptides has enabled achievement of many desirable goals over-riding some of the major disadvantages associated with the delivery of peptides in vivo. Conjugation or physical encapsulation of peptides to various nanocarriers, such as liposomes, micelles and solid-lipid nanoparticles, has improved their in vivo performance multi-fold. The amenability of peptides to modification in chemistry and functionalization with suitable nanocarriers are very relevant aspects in their use and have led to the use of 'smart' nanoparticles with suitable linker chemistries that favor peptide targeting or release at the desired sites, minimizing off-target effects. This review focuses on how nanotechnology has been used to improve the number of peptide applications. The paper also focuses on the chemistry behind peptide conjugation to nanocarriers, the commonly employed linker chemistries and the several improvements that have already been achieved in the areas of peptide use with the help of nanotechnology.

  20. Radiolabeled cyclic RGD peptides as radiotracers for tumor imaging.

    Science.gov (United States)

    Shi, Jiyun; Wang, Fan; Liu, Shuang

    2016-01-01

    The integrin family comprises 24 transmembrane receptors, each a heterodimeric combination of one of 18α and one of 8β subunits. Their main function is to integrate the cell adhesion and interaction with the extracellular microenvironment with the intracellular signaling and cytoskeletal rearrangement through transmitting signals across the cell membrane upon ligand binding. Integrin αvβ3 is a receptor for the extracellular matrix proteins containing arginine-glycine-aspartic (RGD) tripeptide sequence. The αvβ3 is generally expressed in low levels on the epithelial cells and mature endothelial cells, but it is highly expressed in many solid tumors. The αvβ3 levels correlate well with the potential for tumor metastasis and aggressiveness, which make it an important biological target for development of antiangiogenic drugs, and molecular imaging probes for early tumor diagnosis. Over the last decade, many radiolabeled cyclic RGD peptides have been evaluated as radiotracers for imaging tumors by SPECT or PET. Even though they are called "αvβ3-targeted" radiotracers, the radiolabeled cyclic RGD peptides are also able to bind αvβ5, α5β1, α6β4, α4β1, and αvβ6 integrins, which may help enhance their tumor uptake due to the "increased receptor population." This article will use the multimeric cyclic RGD peptides as examples to illustrate basic principles for development of integrin-targeted radiotracers and focus on different approaches to maximize their tumor uptake and T/B ratios. It will also discuss important assays for pre-clinical evaluations of the integrin-targeted radiotracers, and their potential applications as molecular imaging tools for noninvasive monitoring of tumor metastasis and early detection of the tumor response to antiangiogenic therapy.

  1. Peptides and Food Intake

    Science.gov (United States)

    Sobrino Crespo, Carmen; Perianes Cachero, Aránzazu; Puebla Jiménez, Lilian; Barrios, Vicente; Arilla Ferreiro, Eduardo

    2014-01-01

    The mechanisms for controlling food intake involve mainly an interplay between gut, brain, and adipose tissue (AT), among the major organs. Parasympathetic, sympathetic, and other systems are required for communication between the brain satiety center, gut, and AT. These neuronal circuits include a variety of peptides and hormones, being ghrelin the only orexigenic molecule known, whereas the plethora of other factors are inhibitors of appetite, suggesting its physiological relevance in the regulation of food intake and energy homeostasis. Nutrients generated by food digestion have been proposed to activate G-protein-coupled receptors on the luminal side of enteroendocrine cells, e.g., the L-cells. This stimulates the release of gut hormones into the circulation such as glucagon-like peptide-1 (GLP-1), oxyntomodulin, pancreatic polypeptides, peptide tyrosine tyrosine, and cholecystokinin, which inhibit appetite. Ghrelin is a peptide secreted from the stomach and, in contrast to other gut hormones, plasma levels decrease after a meal and potently stimulate food intake. Other circulating factors such as insulin and leptin relay information regarding long-term energy stores. Both hormones circulate at proportional levels to body fat content, enter the CNS proportionally to their plasma levels, and reduce food intake. Circulating hormones can influence the activity of the arcuate nucleus (ARC) neurons of the hypothalamus, after passing across the median eminence. Circulating factors such as gut hormones may also influence the nucleus of the tractus solitarius (NTS) through the adjacent circumventricular organ. On the other hand, gastrointestinal vagal afferents converge in the NTS of the brainstem. Neural projections from the NTS, in turn, carry signals to the hypothalamus. The ARC acts as an integrative center, with two major subpopulations of neurons influencing appetite, one of them coexpressing neuropeptide Y and agouti-related protein (AgRP) that increases food

  2. Anticancer peptides from bacteria

    Directory of Open Access Journals (Sweden)

    Tomasz M. Karpiński

    2013-08-01

    Full Text Available Cancer is a leading cause of death in the world. The rapid development of medicine and pharmacology allows to create new and effective anticancer drugs. Among modern anticancer drugs are bacterial proteins. Until now has been shown anticancer activity among others azurin and exotoxin A from Pseudomonas aeruginosa, Pep27anal2 from Streptococcus pneumoniae, diphtheria toxin from Corynebacterium diphtheriae, and recently discovered Entap from Enterococcus sp. The study presents the current data regarding the properties, action and anticancer activity of listed peptides.

  3. Peptide Vaccines for Cancer

    Directory of Open Access Journals (Sweden)

    Kono K

    2013-10-01

    Full Text Available Background: In general, the preferable characteristic of the target molecules for development of cancer vaccines are high immunogenicity, very common expression in cancer cells, specific expression in cancer cells and essential molecules for cell survival (to avoid loss of expression. We previously reported that three novel HLA-A24-restricted immunodominant peptides, which were derived from three different oncoantigens, TTK, LY6K, and IMP-3,were promising targets for cancer vaccination for esophageal squamous cell carcinoma (ESCCpatients. Then, we had performed a phase I clinical trial using three HLA-A24-binding peptides and the results had been shown to be promising for ESCC. Therefore, we further performed a multicenter, non-randomized phase II clinical trial. Patients and Methods: Sixty ESCC patients were enrolled to evaluate OS, PFS, immunological response employing ELISPOT and pentamer assays. Each of the three peptides was administered with IFA weekly. All patients received the vaccination without knowing an HLA-A type, and the HLA types were key-opened at the analysis point. Hence, the endpoints were set to evaluate differences between HLA-A*2402-positive (24(+ and -negative (24(- groups. Results: The OS in the 24 (+ group (n=35 tended to be better than that in the 24(- group (n=25 (MST 4.6 vs. 2.6 month, respectively, p = 0.121, although the difference was not statistically significant. However, the PFS in the 24(+ group was significantly better than that in the 24(- group (p = 0.032. In the 24(+ group, ELISPOT assay indicated that the LY6K-, TTK-, and IMP3-specific CTL responses were observed after the vaccination in 63%, 45%, and 60% of the 24(+ group, respectively. The patients having LY6K-, TTK-, and IMP3-specific CTL responses revealed the better OS than those not having CTL induction, respectively. The patients showing the CTL induction for multiple peptides have better clinical responses. Conclusion: The immune response induced

  4. Gamma-glutamyltransferase, aspartate aminotransferase and alkaline phosphatase as markers of alcohol consumption in out-patient alcoholics

    DEFF Research Database (Denmark)

    Gluud, C; Andersen, I; Dietrichson, O

    1981-01-01

    and alkaline phosphatase in 18% and 7%. Neither the activity of gamma-glutamyltransferase, aspartate aminotransferase nor alkaline phosphatase showed any significant (P greater than 0.05) correlation with the history of alcohol consumption. The activities of gamma-glutamyltransferase and aspartate...... aminotransferase were raised significantly more often in patients with recent alcohol consumption than in patients who had abstained for more than 9 days. The concentration of alkaline phosphatase was not significantly (P greater than 0.05) different in these groups. The predictive value of raised and normal...... activities of gamma-glutamyltransferase, in deciding whether a patient had had recent alcohol consumption or not, was not superior to the predictive value of raised and normal activities of aspartate aminotransferase....

  5. Use of protease sensitivity to probe the conformations of newly synthesised mutant forms of mitochondrial aspartate aminotransferase.

    Science.gov (United States)

    Azzariti, A; Giannattasio, S; Doonan, S; Merafina, R S; Marra, E; Quagliariello, E

    1995-10-24

    Sensitivity to digestion with pronase has been used to show that the precursor form of mitochondrial aspartate aminotransferase, the form lacking the N-terminal presequence, that with a deletion of the first 9 residues and mutants of the mature enzyme in which residue Cys-166 is mutated to alanine or serine, all retain unfolded conformations after synthesis in a reticulocyte lysate. In the presence of lysed mitochondria the various forms of mitochondrial aspartate aminotransferase retained their susceptibilities to pronase in a way that mirrored the efficiencies with which they are imported into intact mitochondria. The results are interpreted as showing that the presequence of mitochondrial aspartate aminotransferase is not uniquely required for interaction with cytosolic factors required to maintain the newly synthesised protein in a form competent for interacting with, and being imported into, mitochondria.

  6. Molecularly imprinted polymer-matrix nanocomposite for enantioselective electrochemical sensing of D- and L-aspartic acid

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Bhim Bali, E-mail: prof.bbpd@yahoo.com; Srivastava, Amrita; Tiwari, Mahavir Prasad

    2013-10-15

    A new molecularly imprinted polymer-matrix (titanium dioxide nanoparticle/multiwalled carbon nanotubes) nanocomposite was developed for the modification of pencil graphite electrode as an enantioselective sensing probe for aspartic acid isomers, prevalent at ultra trace level in aqueous and real samples. The nanocomposite having many shape complementary cavities was synthesized adopting surface initiated-activators regenerated by electron transfer for atom transfer radical polymerization. The proposed sensor has high stability, nanocomposite uniformity, good reproducibility, and enhanced electrocatalytic activity to respond oxidative peak current of L-aspartic acid quantitatively by differential pulse anodic stripping voltammetry, without any cross-reactivity in real samples. Under the optimized operating conditions, the L-aspartic acid imprinted modified electrode showed a wide linear response for L-aspartic acid within the concentration range 9.98–532.72 ng mL{sup −1}, with the minimum detection limit of 1.73–1.79 ng mL{sup −1} (S/N = 3) in aqueous and real samples. Almost similar stringent limit (1.79 ng mL{sup −1}) was obtained with cerebrospinal fluid which is typical for the primitive diagnosis of neurological disorders, caused by an acute depletion of L-aspartic acid biomarker, in clinical settings. Highlights: • We have adopted surface initiated-activators regenerated by electron transfer for atom transfer radical polymerization. • This approach takes advantage of the nanostructured ultrathin imprinted film. • Successful enantioselective sensing and ultratrace analysis of D- and L-aspartic acid. • Stringent detection limit without any non-specific false-positive contribution.

  7. RC1339/APRc from Rickettsia conorii is a novel aspartic protease with properties of retropepsin-like enzymes.

    Directory of Open Access Journals (Sweden)

    Rui Cruz

    2014-08-01

    Full Text Available Members of the species Rickettsia are obligate intracellular, gram-negative, arthropod-borne pathogens of humans and other mammals. The life-threatening character of diseases caused by many Rickettsia species and the lack of reliable protective vaccine against rickettsioses strengthens the importance of identifying new protein factors for the potential development of innovative therapeutic tools. Herein, we report the identification and characterization of a novel membrane-embedded retropepsin-like homologue, highly conserved in 55 Rickettsia genomes. Using R. conorii gene homologue RC1339 as our working model, we demonstrate that, despite the low overall sequence similarity to retropepsins, the gene product of rc1339 APRc (for Aspartic Protease from Rickettsia conorii is an active enzyme with features highly reminiscent of this family of aspartic proteases, such as autolytic activity impaired by mutation of the catalytic aspartate, accumulation in the dimeric form, optimal activity at pH 6, and inhibition by specific HIV-1 protease inhibitors. Moreover, specificity preferences determined by a high-throughput profiling approach confirmed common preferences between this novel rickettsial enzyme and other aspartic proteases, both retropepsins and pepsin-like. This is the first report on a retropepsin-like protease in gram-negative intracellular bacteria such as Rickettsia, contributing to the analysis of the evolutionary relationships between the two types of aspartic proteases. Additionally, we have also shown that APRc is transcribed and translated in R. conorii and R. rickettsii and is integrated into the outer membrane of both species. Finally, we demonstrated that APRc is sufficient to catalyze the in vitro processing of two conserved high molecular weight autotransporter adhesin/invasion proteins, Sca5/OmpB and Sca0/OmpA, thereby suggesting the participation of this enzyme in a relevant proteolytic pathway in rickettsial life-cycle. As a

  8. Oral administration of a medium containing both D-aspartate-producing live bacteria and D-aspartate reduces rectal temperature in chicks.

    Science.gov (United States)

    Do, P H; Tran, P V; Bahry, M A; Yang, H; Han, G; Tsuchiya, A; Asami, Y; Furuse, M; Chowdhury, V S

    2017-10-01

    1. The aim of this study was to investigate the effects on the rectal temperature of young chicks of the oral administration of a medium that contained both live bacteria that produce D-aspartate (D-Asp) and D-Asp. 2. In Experiment 1, chicks were subjected to chronic oral administration of either the medium (containing live bacteria and 2.46 μmol D-Asp) or water from 7 to 14 d of age. Plasma-free amino acids as well as mitochondrial biogenic gene expression in the breast muscle were analysed. In Experiment 2, 7-d-old chicks were subjected to acute oral administration of the above medium or of an equimolar amount of D-Asp to examine their effect on changes in rectal temperature. In Experiment 3, after 1 week of chronic oral administration of the medium, 14-d-old chicks were exposed to either high ambient temperature (HT; 40 ± 1°C, 3 h) or control thermoneutral temperature (CT; 30 ± 1°C, 3 h) to monitor the changes in rectal temperature. 3. Chronic, but not acute, oral administration of the medium significantly reduced rectal temperature in chicks, and a chronic effect also appeared under HT conditions. 4. Chronic oral administration of the medium significantly reduced the mRNA abundance of the avian uncoupling protein (avUCP) in the breast muscle, but led to a significant increase in avian adenine nucleotide translocator (avANT) mRNA in the same muscle. 5. (a) These results indicate that the medium can reduce body temperature through the decline in avUCP mRNA expression in the breast muscle that may be involved in reduced mitochondrial proton leaks and heat production. (b) The increase in avANT further suggests a possible enhancement of adenosine triphosphate (ATP) synthesis.

  9. Subcritical Water Hydrolysis of Peptides: Amino Acid Side-Chain Modifications

    Science.gov (United States)

    Powell, Thomas; Bowra, Steve; Cooper, Helen J.

    2017-09-01

    Previously we have shown that subcritical water may be used as an alternative to enzymatic digestion in the proteolysis of proteins for bottom-up proteomics. Subcritical water hydrolysis of proteins was shown to result in protein sequence coverages greater than or equal to that obtained following digestion with trypsin; however, the percentage of peptide spectral matches for the samples treated with trypsin were consistently greater than for those treated with subcritical water. This observation suggests that in addition to cleavage of the peptide bond, subcritical water treatment results in other hydrolysis products, possibly due to modifications of amino acid side chains. Here, a model peptide comprising all common amino acid residues (VQSIKCADFLHYMENPTWGR) and two further model peptides (VCFQYMDRGDR and VQSIKADFLHYENPTWGR) were treated with subcritical water with the aim of probing any induced amino acid side-chain modifications. The hydrolysis products were analyzed by direct infusion electrospray tandem mass spectrometry, either collision-induced dissociation or electron transfer dissociation, and liquid chromatography collision-induced dissociation tandem mass spectrometry. The results show preferential oxidation of cysteine to sulfinic and sulfonic acid, and oxidation of methionine. In the absence of cysteine and methionine, oxidation of tryptophan was observed. In addition, water loss from aspartic acid and C-terminal amidation were observed in harsher subcritical water conditions. [Figure not available: see fulltext.

  10. Natriuretic peptides in cardiometabolic regulation and disease

    DEFF Research Database (Denmark)

    Zois, Nora E; Bartels, Emil D; Hunter, Ingrid

    2014-01-01

    these conditions can coexist and potentially lead to heart failure, a syndrome associated with a functional natriuretic peptide deficiency despite high circulating concentrations of immunoreactive peptides. Therefore, dysregulation of the natriuretic peptide system, a 'natriuretic handicap', might be an important...

  11. Pyruvate carboxylation enables growth of SDH-deficient cells by supporting aspartate biosynthesis.

    Science.gov (United States)

    Cardaci, Simone; Zheng, Liang; MacKay, Gillian; van den Broek, Niels J F; MacKenzie, Elaine D; Nixon, Colin; Stevenson, David; Tumanov, Sergey; Bulusu, Vinay; Kamphorst, Jurre J; Vazquez, Alexei; Fleming, Stewart; Schiavi, Francesca; Kalna, Gabriela; Blyth, Karen; Strathdee, Douglas; Gottlieb, Eyal

    2015-10-01

    Succinate dehydrogenase (SDH) is a heterotetrameric nuclear-encoded complex responsible for the oxidation of succinate to fumarate in the tricarboxylic acid cycle. Loss-of-function mutations in any of the SDH genes are associated with cancer formation. However, the impact of SDH loss on cell metabolism and the mechanisms enabling growth of SDH-defective cells are largely unknown. Here, we generated Sdhb-ablated kidney mouse cells and used comparative metabolomics and stable-isotope-labelling approaches to identify nutritional requirements and metabolic adaptations to SDH loss. We found that lack of SDH activity commits cells to consume extracellular pyruvate, which sustains Warburg-like bioenergetic features. We further demonstrated that pyruvate carboxylation diverts glucose-derived carbons into aspartate biosynthesis, thus sustaining cell growth. By identifying pyruvate carboxylase as essential for the proliferation and tumorigenic capacity of SDH-deficient cells, this study revealed a metabolic vulnerability for potential future treatment of SDH-associated malignancies.

  12. Expansion of the aspartate [beta]-semialdehyde dehydrogenase family: the first structure of a fungal ortholog

    Energy Technology Data Exchange (ETDEWEB)

    Arachea, B.T.; Liu, X.; Pavlovsky, A.G.; Viola, R.E. (Toledo)

    2010-08-13

    The enzyme aspartate semialdehyde dehydrogenase (ASADH) catalyzes a critical transformation that produces the first branch-point intermediate in an essential microbial amino-acid biosynthetic pathway. The first structure of an ASADH isolated from a fungal species (Candida albicans) has been determined as a complex with its pyridine nucleotide cofactor. This enzyme is a functional dimer, with a similar overall fold and domain organization to the structurally characterized bacterial ASADHs. However, there are differences in the secondary-structural elements and in cofactor binding that are likely to cause the lower catalytic efficiency of this fungal enzyme. Alterations in the dimer interface, through deletion of a helical subdomain and replacement of amino acids that participate in a hydrogen-bonding network, interrupt the intersubunit-communication channels required to support an alternating-site catalytic mechanism. The detailed functional information derived from this new structure will allow an assessment of ASADH as a possible target for antifungal drug development.

  13. Pseudoallosteric modulation by (+)-MK801 of NMDA (N-methyl-D-aspartate)-coupled phencyclidine binding sites

    Energy Technology Data Exchange (ETDEWEB)

    Reid, A.A.; Monn, J.A.; Jacobson, A.E.; Rice, K.C.; Rothman, R.B. (National Institutes of Health, Bethesda, MD (USA))

    1990-01-01

    Two high affinity phencyclidine (PCP) binding sites, labeled by ({sup 3}H)1-(1-(2-thienyl)cyclohexyl)piperidine (({sup 3}H)TCP), have been identified in guinea pig brain, with one site coupled to the N-methyl-D-aspartate (NMDA) receptor (site 1) and the other site associated with the dopamine reuptake carrier complex (site 2). In this study, PCP enhanced the dissociation of ({sup 3}H)TCP from PCP site 1 and site 2, while (+){minus}MK801 only enhanced dissociation of ({sup 3}H)TCP from PCP site 1. Although additional studies will be required to determine the exact mechanism(s) of these effects, these data demonstrate that the interactions of PCP with both site 1 and site 2 are more complex than previously appreciated.

  14. Cloning and expression of the human N-methyl-D-aspartate receptor subunit NR3A

    DEFF Research Database (Denmark)

    Eriksson, Maria; Nilsson, Anna; Froelich-Fabre, Susanne

    2002-01-01

    Native N-methyl-D-aspartate (NMDA) receptors are heteromeric assemblies of four or five subunits. The NMDA receptor subunits, NR1, NR2A, NR2B, NR2C, and NR2D have been cloned in several species, including man. The NR3A subunit, which in rodents is predominantly expressed during early development......, seems to function by reducing the NMDA receptor response. The human homologue to the rat NR3A, however, had not been cloned. In order to study the functions of the human NR3A (hNR3A), we have cloned and sequenced the hNR3A. It was found to share 88% of the DNA sequence with the rat gene, corresponding...

  15. Anti-N-Methyl-D-Aspartate Receptor Encephalitis in HIV Infection.

    Science.gov (United States)

    Patarata, Eunice; Bernardino, Vera; Martins, Ana; Pereira, Rui; Loureiro, Conceição; Moraes-Fontes, Maria Francisca

    2016-01-01

    Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a rare condition characterized by emotional and behavioral disturbances, dyskinesias, and extrapyramidal signs. It occurs in young women of reproductive age and is classically described as a paraneoplastic phenomenon. We present a 36-year-old, HIV-positive female who was admitted to the hospital in an acute confusional state, with a stiff posture, periods of motor agitation, and myoclonic jerks of the hands. Her mental state progressively deteriorated. Without evidence of infection, the presence of anti-NMDAR antibodies both in serum and cerebrospinal fluid clinched the diagnosis of autoimmune encephalitis. No evidence of neoplastic disease was found, and the beneficial response to immunosuppressive therapy was exceptional. This is the first report of anti-NMDAR encephalitis in an HIV-infected individual, reminding us that autoimmune encephalitis should be included in the differential diagnosis of a young patient presenting in an acute confusional state.

  16. Synthesis, Characterization, and Antimicrobial Activities of Coordination Compounds of Aspartic Acid

    Directory of Open Access Journals (Sweden)

    T. O. Aiyelabola

    2016-01-01

    Full Text Available Coordination compounds of aspartic acid were synthesized in basic and acidic media, with metal ligand M : L stoichiometric ratio 1 : 2. The complexes were characterized using infrared, electronic and magnetic susceptibility measurements, and mass spectrometry. Antimicrobial activity of the compounds was determined against three Gram-positive and three Gram-negative bacteria and one fungus. The results obtained indicated that the availability of donor atoms used for coordination was a function of the pH of the solution in which the reaction was carried out. This resulted in varying geometrical structures for the complexes. The compounds exhibited a broad spectrum of activity and in some cases better activity than the standard.

  17. [Subcellular localization, purification, and various catalitic properties of aspartate aminotransferase from Spirodela polyrhiza].

    Science.gov (United States)

    Rakhmanova, T I; Popova, T N; Semenikhina, A V

    2006-01-01

    Intracellular distribution of aspartate aminotransferase (AAT) in Spirodela polyrhiza (Lemnaceae), strain SJ, has been studied by differential centrifugation. The bulk of the enzyme (73% of total cellular content) was localized in the cytoplasm and 24% activity was localized in chloroplasts. Purified cytoplasmic and chloroplastic isozymes differed by their affinity for substrates. The reaction balance was shifted towards direct and reverse transamination in the cytoplasm and chloroplast, respectively. Competitive inhibition of AAT by excessive substrates and enzyme affinity modulation by certain intermediates of the tricarboxylic acid cycle (isocitrate, succinate, and citrate) were observed. Possible involvement of AAT isozymes in the coordination of carbon and nitrogen metabolism through the regulation of 2-oxoglutarate synthesis and utilization in different cellular compartments is discussed.

  18. Stability of binary complexes of L-aspartic acid in dioxan–water mixtures

    Directory of Open Access Journals (Sweden)

    R.S. Rani

    2013-09-01

    Full Text Available Speciation of binary complexes of Co(II, Ni(II and Cu(II with L-aspartic acid in (0–60% v/v 1,4-dioxan (Dox-water mixtures was studied pH metrically at 303±0.1 K and at an ionic strength of 0.16 M. The models contained ML, ML2, ML2H2, ML2H3 and ML2H4 species. The trend in the variation of stability constants with Dox content was explained on the basis of electrostatic and non-electrostatic forces. Distribution of the species with pH at different compositions of Dox-water media was also presented.DOI: http://dx.doi.org/10.4314/bcse.v27i3.5

  19. Anti-N-Methyl-D-Aspartate Receptor Encephalitis in HIV Infection

    Directory of Open Access Journals (Sweden)

    Eunice Patarata

    2016-12-01

    Full Text Available Anti-N-methyl-D-aspartate receptor (anti-NMDAR encephalitis is a rare condition characterized by emotional and behavioral disturbances, dyskinesias, and extrapyramidal signs. It occurs in young women of reproductive age and is classically described as a paraneoplastic phenomenon. We present a 36-year-old, HIV-positive female who was admitted to the hospital in an acute confusional state, with a stiff posture, periods of motor agitation, and myoclonic jerks of the hands. Her mental state progressively deteriorated. Without evidence of infection, the presence of anti-NMDAR antibodies both in serum and cerebrospinal fluid clinched the diagnosis of autoimmune encephalitis. No evidence of neoplastic disease was found, and the beneficial response to immunosuppressive therapy was exceptional. This is the first report of anti-NMDAR encephalitis in an HIV-infected individual, reminding us that autoimmune encephalitis should be included in the differential diagnosis of a young patient presenting in an acute confusional state.

  20. The aspartic proteinase from Saccharomyces cerevisiae folds its own inhibitor into a helix

    DEFF Research Database (Denmark)

    Li, M; Phylip, L H; Lees, W E

    2000-01-01

    .2 and 1.8 A, respectively, for complexes of proteinase A with full-length IA3 and with a truncated form consisting only of residues 2-34, reveal an unprecedented mode of inhibitor-enzyme interactions. Neither form of the free inhibitor has detectable intrinsic secondary structure in solution. However......, upon contact with the enzyme, residues 2-32 become ordered and adopt a near-perfect alpha-helical conformation. Thus, the proteinase acts as a folding template, stabilizing the helical conformation in the inhibitor, which results in the potent and specific blockage of the proteolytic activity.......Aspartic proteinase A from yeast is specifically and potently inhibited by a small protein called IA3 from Saccharomyces cerevisiae. Although this inhibitor consists of 68 residues, we show that the inhibitory activity resides within the N-terminal half of the molecule. Structures solved at 2...

  1. Correlation of Global N-Acetyl Aspartate With Cognitive Impairment in Multiple Sclerosis

    DEFF Research Database (Denmark)

    Kahr Mathiesen, Henrik; Jonsson, Agnete; Tscherning, Thomas

    2006-01-01

    than conventional magnetic resonance imaging measures. DESIGN: Survey. SETTING: Research-oriented hospitals.Patients Twenty patients, 16 women and 4 men (mean age, 36 years), with early relapsing-remitting multiple sclerosis (mean Expanded Disability Status Scale score, 2.5). MAIN OUTCOME MEASURES......BACKGROUND: Whole-brain N-acetyl aspartate (NAA), a measure of neuronal function, can be assessed by multislice echo-planar spectroscopic imaging. OBJECTIVE: To test the hypothesis that the global brain NAA/creatine (Cr) ratio is a better predictor of cognitive dysfunction in multiple sclerosis......: Correlation between the global NAA/Cr ratio and a cognitive dysfunction factor comprising 16 measures from an extensive neuropsychological test battery that best distinguished patients with multiple sclerosis from healthy control subjects. RESULTS: A significant partial correlation between the global NAA...

  2. Cumulative effects of mutations in newly synthesised mitochondrial aspartate aminotransferase on uptake into mitochondria.

    Science.gov (United States)

    Marra, E; Azzariti, A; Giannattasio, S; Doonan, S; Quagliariello, E

    1995-09-14

    Mutant genes were constructed which coded for the precursor form of mitochondrial aspartate aminotransferase in which residue cysteine 166 was mutated to either serine or alanine and for forms of the protein lacking both the presequence and residues 1-9 of the mature protein but carrying the same cysteine mutations. The protein products of all of these mutant genes were imported into mitochondria that had been added to the expression system but with varying degrees of efficiency. The results showed that the effects of mutation of cysteine 166 and of deletion of residues 1-9 of the mature protein on sequestration into mitochondria were essentially cumulative, suggesting that these parts of the protein are involved in distinct steps on the recognition/uptake pathway.

  3. Protonation Equilibria of L-Aspartic, Citric and Succinic Acids in Anionic Micellar Media

    Directory of Open Access Journals (Sweden)

    P. Srinivasa Rao

    2009-01-01

    Full Text Available The impact of sodium lauryl sulphate (SLS on the protonation equilibria of L-aspartic acid, citric acid and succinic acid has been studied in various concentrations (0.5-2.5% w/v of SLS solution maintaining an ionic strength of 0.16 mol dm-3 at 303 K. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models have been calculated based on statistical parameters. The trend of log values of step-wise protonation constants with mole fraction of the medium has been explained based on electrostatic and non-electrostatic forces operating on the protonation equilibria. The effects of errors on the protonation constants have also been presented.

  4. Chemical Synthesis of Antimicrobial Peptides.

    Science.gov (United States)

    Münzker, Lena; Oddo, Alberto; Hansen, Paul R

    2017-01-01

    Solid-phase peptide synthesis (SPPS) is the method of choice for chemical synthesis of peptides. In this nonspecialist review, we describe commonly used resins, linkers, protecting groups, and coupling reagents in 9-fluorenylmethyloxycarbonyl (Fmoc) SPPS. Finally, a detailed protocol for manual Fmoc SPPS is presented.

  5. Urinary Peptides in Rett Syndrome.

    Science.gov (United States)

    Solaas, K. M.; Skjeldal, O.; Gardner, M. L. G.; Kase, B. F.; Reichelt, K. L.

    2002-01-01

    A study found a significantly higher level of peptides in the urine of 53 girls with Rett syndrome compared with controls. The elevation was similar to that in 35 girls with infantile autism. Levels of peptides were lower in girls with classic Rett syndrome than those with congenital Rett syndrome. (Contains references.) (Author/CR)

  6. Peptides: A new class of anticancer drugs

    OpenAIRE

    Ryszard Smolarczyk; Tomasz Cichoń; Stanisław Szala

    2009-01-01

    Peptides are a novel class of anticancer agents embracing two distinct categories: natural antibacterial peptides, which are preferentially bound by cancer cells, and chemically synthesized peptides, which bind specifically to precise molecular targets located on the surface of tumor cells. Antibacterial peptides bind to both cell and mitochondrial membranes. Some of these peptides attach to the cell membrane, resulting in its disorganization. Other antibacterial peptides penetrate cancer cel...

  7. A Histidine Aspartate Ionic Lock Gates the Iron Passage in Miniferritins from Mycobacterium smegmatis*

    Science.gov (United States)

    Williams, Sunanda Margrett; Chandran, Anu V.; Vijayabaskar, Mahalingam S.; Roy, Sourav; Balaram, Hemalatha; Vishveshwara, Saraswathi; Vijayan, Mamannamana; Chatterji, Dipankar

    2014-01-01

    Dps (DNA-binding protein from starved cells) are dodecameric assemblies belonging to the ferritin family that can bind DNA, carry out ferroxidation, and store iron in their shells. The ferritin-like trimeric pore harbors the channel for the entry and exit of iron. By representing the structure of Dps as a network we have identified a charge-driven interface formed by a histidine aspartate cluster at the pore interface unique to Mycobacterium smegmatis Dps protein, MsDps2. Site-directed mutagenesis was employed to generate mutants to disrupt the charged interactions. Kinetics of iron uptake/release of the wild type and mutants were compared. Crystal structures were solved at a resolution of 1.8–2.2 Å for the various mutants to compare structural alterations vis à vis the wild type protein. The substitutions at the pore interface resulted in alterations in the side chain conformations leading to an overall weakening of the interface network, especially in cases of substitutions that alter the charge at the pore interface. Contrary to earlier findings where conserved aspartate residues were found crucial for iron release, we propose here that in the case of MsDps2, it is the interplay of negative-positive potentials at the pore that enables proper functioning of the protein. In similar studies in ferritins, negative and positive patches near the iron exit pore were found to be important in iron uptake/release kinetics. The unique ionic cluster in MsDps2 makes it a suitable candidate to act as nano-delivery vehicle, as these gated pores can be manipulated to exhibit conformations allowing for slow or fast rates of iron release. PMID:24573673

  8. Structural Model of the R State of Escherichia coli Aspartate Transcarbamoylase with Substrates Bound

    Energy Technology Data Exchange (ETDEWEB)

    Wang,J.; Eldo, J.; Kantrowitz, E.

    2007-01-01

    The allosteric enzyme aspartate transcarbamoylase (ATCase) exists in two conformational states. The enzyme, in the absence of substrates is primarily in the low-activity T state, is converted to the high-activity R state upon substrate binding, and remains in the R state until substrates are exhausted. These conformational changes have made it difficult to obtain structural data on R-state active-site complexes. Here we report the R-state structure of ATCase with the substrate Asp and the substrate analog phosphonoactamide (PAM) bound. This R-state structure represents the stage in the catalytic mechanism immediately before the formation of the covalent bond between the nitrogen of the amino group of Asp and the carbonyl carbon of carbamoyl phosphate. The binding mode of the PAM is similar to the binding mode of the phosphonate moiety of N-(phosphonoacetyl)-l-aspartate (PALA), the carboxylates of Asp interact with the same residues that interact with the carboxylates of PALA, although the position and orientations are shifted. The amino group of Asp is 2.9 {angstrom} away from the carbonyl oxygen of PAM, positioned correctly for the nucleophilic attack. Arg105 and Leu267 in the catalytic chain interact with PAM and Asp and help to position the substrates correctly for catalysis. This structure fills a key gap in the structural determination of each of the steps in the catalytic cycle. By combining these data with previously determined structures we can now visualize the allosteric transition through detailed atomic motions that underlie the molecular mechanism.

  9. Proteolysis of the peanut allergen Ara h 1 by an endogenous aspartic protease.

    Science.gov (United States)

    Wilson, Karl A; Tan-Wilson, Anna

    2015-11-01

    The 7S and 11S globulins of peanuts are subjected to proteolysis two days after seed imbibition, with Ara h 1 and the arachin acidic chains being among the first storage proteins to be mobilized. Proteolytic activity was greatest at pH 2.6-3 and is inhibited by pepstatin A, characteristic of an aspartic protease. This activity persists in seedling cotyledons up to at least 8 days after imbibition. In vitro proteolysis of Ara h 1 at pH 2.6 by extracts of cotyledons from seedlings harvested 24 h after seed imbibition generates newly appearing bands on SDS-PAGE. Partial sequences of Ara h 1 that were obtained through LC-MS/MS analysis of in-gel trypsin digests of those bands, combined with information on fragment size, suggest that proteolysis begins in the region that links the two cupin domains to produce two 33/34 kD fragments, each one encompassing an intact cupin domain. The later appearance of two 18 and 10/11 kD fragments can be explained by proteolysis within an exposed site in the cupin domains of each of the 33/34 kD fragments. The same or similar proteolytic activity was observed in developing seeds, but Ara h 1 remains intact through seed maturation. This is partly explained by the observation that acidification of the protein storage vacuoles, demonstrated by vacuolar accumulation of acridine orange that was dissipated by a membrane-permeable base, occurs only after germination. These findings suggest a method for use of the seed aspartic protease in reducing peanut allergy due to Ara h 1. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. Production and Characterization of Monoclonal Antibodies against Aspartate Aminotransferase-P1 from Lupin Root Nodules.

    Science.gov (United States)

    Jones, W. T.; Jones, S. D.; Harvey, D.; Rodber, K. R.; Ryan, G. B.; Reynolds, PHS.

    1994-01-01

    Six hybridoma clones were obtained that secreted monoclonal antibodies against the aspartate aminotransferase-P1 (AAT-P1) isoenzyme from root nodules of Lupinus angustifolius [L.] cv Uniharvest. This enzyme is found constitutively in the plant cytosol fraction. The monoclonal antibodies produced were all of the immunoglobulin G1 class, recognized two distinct epitopes on the protein, and represented the major paratopes found in the immunoglobulin fraction of sera taken from mice and rabbits immunized with the pure AAT-P1 protein. One of these epitopes was unique to lupin nodule AAT-P1. The other epitope was shown to be present on enzyme from lupin bean, white clover and tobacco leaves, lupin roots and nodules, and potato tubers. Both epitopes were recognized by the appropriate monoclonal antibodies in both their native and denatured forms. None of the monoclonal antibodies produced reacted with Rhizobium lupini NZP2257, Escherichia coli extracts, or with the inducible aspartate aminotransferase-P2 (AAT-P2) isoform also found in root nodules. A sandwich enzyme-linked immunosorbent assay utilizing two monoclonal antibodies recognizing the two distinct epitopes was developed and was capable of quantitating AAT-P1 in plant extracts. The limit of detection of AAT-P1 was less than 15 pg/mL and AAT-P1 protein could be quantified in the range 80 to 1000 pg/mL. Using this assay, AAT-P1 protein was shown to remain relatively constant during nodule development. Use of an AAT-P2-specific monoclonal antibody that inhibits the enzyme activity of this isoform enabled the direct determination of AAT-P1 enzyme activity in nodule extracts. Using these assays, specific activities of the individual isoforms were calculated; that of the AAT-P1 isoform was shown to be 7.5-fold higher than that of the AAT-P2 isoform. PMID:12232065

  11. A heterozygous mutation in GOT1 is associated with familial macro-aspartate aminotransferase.

    Science.gov (United States)

    Kulecka, Maria; Wierzbicka, Aldona; Paziewska, Agnieszka; Mikula, Michal; Habior, Andrzej; Janczyk, Wojciech; Dabrowska, Michalina; Karczmarski, Jakub; Lazniewski, Michal; Ginalski, Krzysztof; Czlonkowska, Anna; Socha, Piotr; Ostrowski, Jerzy

    2017-11-01

    Macro-aspartate aminotransferase (macro-AST) manifests as a persistent elevation of AST levels, because of association of the protein with immunoglobulins in the circulation. Macro-AST is a rare, benign condition without a previously confirmed genetic basis. Whole exome sequencing (WES)-based screening was performed on 32 participants with suspected familial macro-AST, while validation of variants was performed on an extended cohort of 92 probands and 1,644 healthy controls using Taqman genotyping. A missense variant (p.Gln208Glu, rs374966349) in glutamate oxaloacetate transaminase 1 (GOT1) was found, as a putative causal variant predisposing to familial macro-AST. The GOT1 p.Gln208Glu mutation was detected in 50 (54.3%) of 92 probands from 20 of 29 (69%) families, while its prevalence in healthy controls was only 0.18%. In silico analysis demonstrated that the amino acid at this position is not conserved among different species and that, functionally, a negatively charged glutamate on the GOT1 surface could strongly anchor serum immunoglobulins. Our data highlight that testing for the p.Gln208Glu genetic variant may be useful in diagnosis of macro-AST. Higher than normal levels of aspartate aminotransferase (AST) in the bloodstream may be a sign of a health problem. Individuals with macro-AST have elevated blood AST levels, without ongoing disease and often undergo unnecessary medical tests before the diagnosis of macro-AST is established. We found a genetic variant in the GOT1 gene associated with macro-AST. Genetic testing for this variant may aid diagnosis of macro-AST. Copyright © 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  12. Peptide-LNA oligonucleotide conjugates

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Hansen, Lykke Haastrup; Vester, Birte

    2013-01-01

    Although peptide-oligonucleotide conjugates (POCs) are well-known for nucleic acids delivery and therapy, reports on internal attachment of peptides to oligonucleotides are limited in number. To develop a convenient route for preparation of internally labeled POCs with improved biomedical...... properties, peptides were introduced into oligonucleotides via a 2'-alkyne-2'-amino-LNA scaffold. Derivatives of methionine- and leucine-enkephalins were chosen as model peptides of mixed amino acid content, which were singly and doubly incorporated into LNA/DNA strands using highly efficient copper......(i)-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry. DNA/RNA target binding affinity and selectivity of the resulting POCs were improved in comparison to LNA/DNA mixmers and unmodified DNA controls. This clearly demonstrates that internal attachment of peptides to oligonucleotides can significantly...

  13. The Equine PeptideAtlas

    DEFF Research Database (Denmark)

    Bundgaard, Louise; Jacobsen, Stine; Sorensen, Mette A.

    2014-01-01

    Progress in MS-based methods for veterinary research and diagnostics is lagging behind compared to the human research, and proteome data of domestic animals is still not well represented in open source data repositories. This is particularly true for the equine species. Here we present a first...... Equine PeptideAtlas encompassing high-resolution tandem MS analyses of 51 samples representing a selection of equine tissues and body fluids from healthy and diseased animals. The raw data were processed through the Trans-Proteomic Pipeline to yield high quality identification of proteins and peptides....... The current release comprises 24 131 distinct peptides representing 2636 canonical proteins observed at false discovery rates of 0.2% at the peptide level and 1.4% at the protein level. Data from the Equine PeptideAtlas are available for experimental planning, validation of new datasets, and as a proteomic...

  14. Maize Bioactive Peptides against Cancer

    Science.gov (United States)

    Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

    2017-06-01

    Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

  15. Comparison of a Multiple Daily Insulin Injection Regimen (Glargine or Detemir Once Daily Plus Prandial Insulin Aspart and Continuous Subcutaneous Insulin Infusion (Aspart in Short-Term Intensive Insulin Therapy for Poorly Controlled Type 2 Diabetes Patients

    Directory of Open Access Journals (Sweden)

    Wen-shan Lv

    2013-01-01

    Full Text Available Aims. To examine the potential differences between multiple daily injection (MDI regimens based on new long-acting insulin analogues (glargine or detemir plus prandial insulin aspart and continuous subcutaneous insulin aspart infusion (CSII in patients with poorly controlled type 2 diabetes. Methods. Patients (n=119 with poorly controlled type 2 diabetes of a duration exceeding five years were randomly assigned into three groups: Group A treated with CSII using insulin aspart; Group B treated with glargine-based MDI and Group C treated with detemir-based MDI. Results. Good glycemic control was achieved by patients in Group A in a significantly shorter duration than patients in Groups B and C. Total daily insulin, basal insulin dose and dose per kg body weight in Group A were significantly less than those in Groups B and C. Daily blood glucose fluctuation in Group A was significantly less than that in Groups B and C. There were no differences between Groups B and C. Conclusions. Aspart-based CSII may achieve good blood glucose control with less insulin doses over a shorter period compared with glargine or detemir-based MDI. No differences between glargine- and detemir-based MDI were detected in poorly controlled subjects with type 2 diabetes.

  16. Peptide-equipped tobacco mosaic virus templates for selective and controllable biomineral deposition

    Directory of Open Access Journals (Sweden)

    Klara Altintoprak

    2015-06-01

    Full Text Available The coating of regular-shaped, readily available nanorod biotemplates with inorganic compounds has attracted increasing interest during recent years. The goal is an effective, bioinspired fabrication of fiber-reinforced composites and robust, miniaturized technical devices. Major challenges in the synthesis of applicable mineralized nanorods lie in selectivity and adjustability of the inorganic material deposited on the biological, rod-shaped backbones, with respect to thickness and surface profile of the resulting coating, as well as the avoidance of aggregation into extended superstructures. Nanotubular tobacco mosaic virus (TMV templates have proved particularly suitable towards this goal: Their multivalent protein coating can be modified by high-surface-density conjugation of peptides, inducing and governing silica deposition from precursor solutions in vitro. In this study, TMV has been equipped with mineralization-directing peptides designed to yield silica coatings in a reliable and predictable manner via precipitation from tetraethoxysilane (TEOS precursors. Three peptide groups were compared regarding their influence on silica polymerization: (i two peptide variants with alternating basic and acidic residues, i.e. lysine–aspartic acid (KDx motifs expected to act as charge-relay systems promoting TEOS hydrolysis and silica polymerization; (ii a tetrahistidine-exposing polypeptide (CA4H4 known to induce silicification due to the positive charge of its clustered imidazole side chains; and (iii two peptides with high ZnO binding affinity. Differential effects on the mineralization of the TMV surface were demonstrated, where a (KDx charge-relay peptide (designed in this study led to the most reproducible and selective silica deposition. A homogenous coating of the biotemplate and tight control of shell thickness were achieved.

  17. Cathepsin-Mediated Cleavage of Peptides from Peptide Amphiphiles Leads to Enhanced Intracellular Peptide Accumulation.

    Science.gov (United States)

    Acar, Handan; Samaeekia, Ravand; Schnorenberg, Mathew R; Sasmal, Dibyendu K; Huang, Jun; Tirrell, Matthew V; LaBelle, James L

    2017-09-20

    Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein-protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation, and PA monomers are internalized via endocytosis. However, endocytotic sequestration and steric hindrance from the lipid tail are two major mechanisms that limit PA efficacy to target intracellular PPIs. To address these problems, we have constructed a PA platform consisting of cathepsin-B cleavable PAs in which a selective p53-based inhibitory peptide is cleaved from its lipid tail within endosomes, allowing for intracellular peptide accumulation and extracellular recycling of the lipid moiety. We monitor for cleavage and follow individual PA components in real time using a Förster resonance energy transfer (FRET)-based tracking system. Using this platform, we provide a better understanding and quantification of cellular internalization, trafficking, and endosomal cleavage of PAs and of the ultimate fates of each component.

  18. Purification and use of E. coli peptide deformylase for peptide deprotection in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia; Sonke, Theo; Quaedflieg, Peter J.; Janssen, Dick B.

    Peptide deformylases (PDFs) catalyze the removal of the formyl group from the N-terminal methionine residue in nascent polypeptide chains in prokaryotes. Its deformylation activity makes PDF an attractive candidate for the biocatalytic deprotection of formylated peptides that are used in

  19. Cathepsin-Mediated Cleavage of Peptides from Peptide Amphiphiles Leads to Enhanced Intracellular Peptide Accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Acar, Handan [Institute; Department; Samaeekia, Ravand [Institute; Department; Schnorenberg, Mathew R. [Institute; Department; Medical; Sasmal, Dibyendu K. [Institute; Huang, Jun [Institute; Tirrell, Matthew V. [Institute; Institute; LaBelle, James L. [Department

    2017-08-24

    Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation, and PA monomers are internalized via endocytosis. However, endocytotic sequestration and steric hindrance from the lipid tail are two major mechanisms that limit PA efficacy to target intracellular PPIs. To address these problems, we have constructed a PA platform consisting of cathepsin-B cleavable PAs in which a selective p53-based inhibitory peptide is cleaved from its lipid tail within endosomes, allowing for intracellular peptide accumulation and extracellular recycling of the lipid moiety. We monitor for cleavage and follow individual PA components in real time using a resonance energy transfer (FRET)-based tracking system. Using this platform, components in real time using a Forster we provide a better understanding and quantification of cellular internalization, trafficking, and endosomal cleavage of PAs and of the ultimate fates of each component.

  20. Clinical experience with insulin detemir, biphasic insulin aspart and insulin aspart in people with type 2 diabetes: Results from the Abu Dhabi cohort of the A 1 chieve study

    Directory of Open Access Journals (Sweden)

    Oula Alhabian

    2013-01-01

    Full Text Available Background: The A 1 chieve, a multicentric (28 countries, 24-week, non-interventional study evaluated the safety and effectiveness of insulin detemir, biphasic insulin aspart and insulin aspart in people with T2DM (n = 66,726 in routine clinical care across four continents. Materials and Methods: Data was collected at baseline, at 12 weeks and at 24 weeks. This short communication presents the results for patients enrolled from Abu Dhabi. Results: A total of 383 patients were enrolled in the study. Four different insulin analogue regimens were used in the study. Study patients had started on or were switched to biphasic insulin aspart (n = 134, insulin detemir (n = 152, insulin aspart (n = 13, basal insulin plus insulin aspart (n = 42 and other insulin combinations (n = 41. At baseline glycaemic control was poor for both insulin naïve (mean HbA 1 c: 9.4% and insulin user (mean HbA 1 c: 9.1% groups. After 24 weeks of treatment, both groups showed improvement in HbA 1 c (insulin naïve: −2.1%, insulin users: −1.8%. SADRs did not occur in any of the study patients. Major hypoglycaemic events remained same as that of baseline (0.1 events/patient-year for insulin naïve group whereas major hypoglycaemia reduced from 0.1 events/patient-year to 0.0 events/patient-year in insulin users. Conclusion: Starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia.

  1. Collagen turnover in normal and degenerate human intervertebral discs as determined by the racemization of aspartic acid

    NARCIS (Netherlands)

    Sivan, S.-S.; Wachtel, E.; Tsitron, E.; Sakkee, N.; Ham, F. van der; Groot, J.de; Roberts, S.; Maroudas, A.

    2008-01-01

    Knowledge of rates of protein turnover is important for a quantitative understanding of tissue synthesis and catabolism. In this work, we have used the racemization of aspartic acid as a marker for the turnover of collagen obtained from healthy and pathological human intervertebral disc matrices. We

  2. Crystal structure of Clostridium acetobutylicum Aspartate kinase (CaAK): An important allosteric enzyme for amino acids production.

    Science.gov (United States)

    Manjasetty, Babu A; Chance, Mark R; Burley, Stephen K; Panjikar, Santosh; Almo, Steven C

    2014-09-01

    Aspartate kinase (AK) is an enzyme which is tightly regulated through feedback control and responsible for the synthesis of 4-phospho-L-aspartate from L-aspartate. This intermediate step is at an important branch point where one path leads to the synthesis of lysine and the other to threonine, methionine and isoleucine. Concerted feedback inhibition of AK is mediated by threonine and lysine and varies between the species. The crystal structure of biotechnologically important Clostridium acetobutylicum aspartate kinase (CaAK; E.C. 2.7.2.4; Mw=48,030Da; 437aa; SwissProt: Q97MC0) has been determined to 3Å resolution. CaAK acquires a protein fold similar to the other known structures of AKs despite the low sequence identity (bacteria such as Clostridium tetani (64% sequence identity) suggesting the potential of the structure solved here to be applied for modeling drug interactions. CaAK structure may serve as a guide to better understand and engineer lysine biosynthesis for the biotechnology industry.

  3. Inhibition of Calpain Prevents N-Methyl-D-aspartate-Induced Degeneration of the Nucleus Basalis and Associated Behavioral Dysfunction

    NARCIS (Netherlands)

    Nimmrich, Volker; Szabo, Robert; Nyakas, Csaba; Granic, Ivica; Reymann, Klaus G.; Schroeder, Ulrich H.; Gross, Gerhard; Schoemaker, Hans; Wicke, Karsten; Moeller, Achim; Luiten, Paul

    2008-01-01

    N-Methyl-D-aspartate( NMDA) receptor-mediated excitotoxicity is thought to underlie a variety of neurological disorders, and inhibition of either the NMDA receptor itself, or molecules of the intracellular cascade, may attenuate neurodegeneration in these diseases. Calpain, a calcium-dependent

  4. [Anesthesia in anti-N-methyl-d-aspartate receptor encephalitis - is general anesthesia a requisite? A case report].

    Science.gov (United States)

    Chaw, Sook Hui; Foo, Li Lian; Chan, Lucy; Wong, Kang Kwong; Abdullah, Suhailah; Lim, Boon Kiong

    Anti-N-methyl-d-aspartate receptor encephalitis is a recently described neurological disorder and an increasingly recognized cause of psychosis, movement disorders and autonomic dysfunction. We report 20-year-old Chinese female who presented with generalized tonic-clonic seizures, recent memory loss, visual hallucinations and abnormal behavior. Anti-N-methyl-d-aspartate receptor encephalitis was diagnosed and a computed tomography scan of abdomen reviewed a left adnexal tumor. We describe the first such case report of a patient with anti-N-methyl-d-aspartate receptor encephalitis who was given a bilateral transversus abdominis plane block as the sole anesthetic for removal of ovarian tumor. We also discuss the anesthetic issues associated with anti-N-methyl-d-aspartate receptor encephalitis. As discovery of tumor and its removal is the focus of initial treatment in this group of patients, anesthetists will encounter more such cases in the near future. Copyright © 2015 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  5. Stimulation of the N-methyl-D-aspartate receptor has a trophic effect on differentiating cerebellar granule cells

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1988-01-01

    N-methyl-D-aspartate (NMDA) supplementation of cerebellar cultures enriched in granule neurones (about 90%) prevented the extensive cell loss which occurs when cultivation takes place, in serum containing media, in the presence of 'low' K+ (5-15 mM). Estimation of tetanus toxin receptors and N-CA...

  6. The potency and specificity of the interaction between the IA3 inhibitor and its target aspartic proteinase from Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Phylip, L H; Lees, W E; Brownsey, B G

    2001-01-01

    The yeast IA3 polypeptide consists of only 68 residues, and the free inhibitor has little intrinsic secondary structure. IA3 showed subnanomolar potency toward its target, proteinase A from Saccharomyces cerevisiae, and did not inhibit any of a large number of aspartic proteinases with similar se...

  7. Pre-ischemic mitochondrial substrate constraint by inhibition of malate-aspartate shuttle preserves mitochondrial function after ischemia-reperfusion

    DEFF Research Database (Denmark)

    Jespersen, Nichlas Riise; Yokota, Takashi; Støttrup, Nicolaj Brejnholt

    2017-01-01

    KEY POINTS: Pre-ischaemic administration of aminooxiacetate (AOA), an inhibitor of the malate-aspartate shuttle (MAS), provides cardioprotection against ischaemia-reperfusion injury. The underlying mechanism remains unknown. We examined whether transient inhibition of the MAS during ischaemia and...

  8. Influence of structural and surface properties of whey-derived peptides on zinc-chelating capacity, and in vitro gastric stability and bioaccessibility of the zinc-peptide complexes.

    Science.gov (United States)

    Udechukwu, M Chinonye; Downey, Brianna; Udenigwe, Chibuike C

    2018-02-01

    Gastrointestinal stability of zinc-peptide complexes is essential for zinc delivery. As peptide surface charge can influence their metal complex stability, we evaluated the zinc-chelating capacity and stability of zinc complexes of whey protein hydrolysates (WPH), produced with Everlase (WPH-Ever; ζ-potential, -39mV) and papain (WPH-Pap; ζ-potential, -7mV), during simulated digestion. WPH-Ever had lower amount of zinc-binding amino acids but showed higher zinc-chelating capacity than WPH-Pap. This is attributable to the highly anionic surface charge of WPH-Ever for electrostatic interaction with zinc. Release of zinc during peptic digestion was lower for WPH-Ever-zinc, and over 50% of zinc remained bound in both peptide complexes after peptic-pancreatic digestion. Fourier transform infrared spectroscopy suggests the involvement of carboxylate ion, and sidechain carbon-oxygen of aspartate/glutamate and serine/threonine in zinc-peptide complexation. The findings indicate that strong zinc chelation can promote gastric stability and impede intestinal release, for peptides intended for use as dietary zinc carriers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Rescue of Na+ and H+ binding in Na+,K+-ATPase M8 aspartate mutants by secondary mutation

    DEFF Research Database (Denmark)

    Holm, Rikke; Einholm, Anja P.; Andersen, Jens Peter

    A mutation replacing the aspartate in transmembrane segment M8 in the a3-isoform of Na,K-ATPase with asparagine has been found in patients with rapid-onset dystonia parkinsonism or alternating hemiplegia of childhood. This aspartate may be a critical Na+ coordinating residue, but the crystal...

  10. Evidence for increased cellular uptake of glutamate and aspartate in the rat hippocampus during kainic acid seizures. A microdialysis study using the "indicator diffusion' method

    DEFF Research Database (Denmark)

    Bruhn, T; Christensen, Thomas; Diemer, Nils Henrik

    1997-01-01

    Using a newly developed technique, based on microdialysis, which allows cellular uptake of glutamate and aspartate to be studied in awake animals, we investigated uptake of glutamate and aspartate in the hippocampal formation of rats during limbic seizures induced by systemical administration...

  11. Targeting the D1-N-methyl-D-aspartate receptor complex reduces L-dopa-induced dyskinesia in 6-hydroxydopamine-lesioned Parkinson’s rats

    Directory of Open Access Journals (Sweden)

    Song L

    2016-02-01

    Full Text Available Lu Song,1,* Zhanzhao Zhang,2,* Rongguo Hu,1 Jie Cheng,1 Lin Li,1 Qinyi Fan,1 Na Wu,1 Jing Gan,1 Mingzhu Zhou,1 Zhenguo Liu11Department of Neurology, Xinhua Hospital, 2Department of Plastic and Reconstructive Surgery, Shanghai 9th People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China*These authors contributed equally to this workAbstract: L-3,4-dihydroxyphenylalanine (L-dopa remains the most effective therapy for Parkinson’s disease (PD, but its long-term administration is associated with the development of debilitating motor complications known as L-dopa-induced dyskinesia (LID. Enhanced function of dopamine D1 receptor (D1R and N-methyl-d-aspartate receptor (NMDAR is believed to participate in the pathogenesis of LID. Given the existence of physical and functional interactions between D1R and NMDAR, we explored the effects of uncoupling D1R and NMDA GluN1 (GluN1 interaction on LID by using the Tat-conjugated interfering peptide (Tat-D1-t2. In this study, we demonstrated in 6-hydroxydopamine (6-OHDA-lesioned PD rat model that intrastriatal injection of Tat-D1-t2 alleviated dyskinetic behaviors and downregulated the phosphorylation of DARPP-32 at Thr34 induced by levodopa. Moreover, we also showed intrastriatal administration of Tat-D1-t2 elicited alterations in membranous GluN1 and D1R expression. These findings indicate that D1R/GluN1 complexes may be a molecular target with therapeutic potential for the treatment of dyskinesia in Parkinson’s patients.Keywords: 6-hydroxydopamine, Parkinson’s disease, dyskinesia, L-dopa, D1 receptor, NMDA, protein–protein interaction

  12. Encapsulation of cell-adhesive RGD peptides into a polymeric physical hydrogel to prevent postoperative tissue adhesion.

    Science.gov (United States)

    Zhang, Zheng; Ni, Jian; Chen, Liang; Yu, Lin; Xu, Jianwei; Ding, Jiandong

    2012-08-01

    Peptides containing the sequence of arginine-glycine-aspartate (RGD), a famous adhesion moiety, can specifically conjugate integrins in cell membranes, and are usually applied to enhance cell adhesion after linking to solid substrates in tissue engineering or to nanoparticles in targeting delivery. This paper reveals, however, that free RGD peptides can assist in preventing tissue adhesion by blocking focal adhesion between cells and surfaces of barrier devices. In order to avoid a rapid peptide loss after straightforward injection of a peptide solution, we employed a thermosensitive injectable hydrogel composed of a biodegradable block copolymer poly(ε-caprolactone-co-lactide)-poly(ethylene glycol)-poly(ε-caprolactone-co-lactide) (PCLA-PEG-PCLA) to encapsulate peptides cyclo(-RGDfK-). A sustainable release for one week was achieved in vitro. The rabbit model of sidewall defect and bowel abrasion was selected to examine the in vivo anti-adhesion efficacy. It reveals a significant reduction of postoperative peritoneal adhesion in the group of RGD-loaded PCLA-PEG-PCLA hydrogels. We interpret this excellent efficacy by the combination of two effects: first, our hydrogel affords a physical barrier to prevent adhesion between injured abdominal wall and cecum; second, the RGD molecules as integrin blockers released from the hydrogel assist the anti-adhesion. Copyright © 2012 Wiley Periodicals, Inc.

  13. Towards rice bran protein utilization: In silico insight on the role of oryzacystatins in biologically-active peptide production.

    Science.gov (United States)

    Udenigwe, Chibuike C

    2016-01-15

    Rice bran proteins (RBP) have been demonstrated to harbour biologically active peptides, which can be released by proteases and applied in human health promotion. In this study, the roles of rice bran cysteine protease inhibitors, oryzacystatins, were considered for efficient production of bioactive peptides from RBP. In silico evidence demonstrates that aspartate protease (pepsin at pH>2) and metalloproteinase (thermolysin) have strong prospects for use in simultaneously cleaving the QXVXGX motif of oryzacystatins, which can lead to their inactivation, and in releasing bioactive sequences from the protease inhibitors. The cleaved bioactive peptides are known to possess activities that can be applied in the management of hypertension, oxidative stress, type 2 diabetes mellitus and other aberrant cellular processes. Moreover, several potentially bioactive di- and tripeptides were identified in oryzacystatin peptide pools. This study provides an important consideration and a direction that can lead to efficient release of bioactive peptides from rice bran proteins for functional food applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Molecular Design: Network Architecture and Its Impact on the Organization and Mechanics of Peptide-Polyurea Hybrids.

    Science.gov (United States)

    Matolyak, Lindsay; Keum, Jong; Korley, LaShanda T J

    2016-12-12

    Nature has achieved controlled and tunable mechanics via hierarchical organization driven by physical and covalent interactions. Polymer-peptide hybrids have been designed to mimic natural materials utilizing these architectural strategies, obtaining diverse mechanical properties, stimuli responsiveness, and bioactivity. Here, utilizing a molecular design pathway, peptide-polyurea hybrid networks were synthesized to investigate the role of architecture and structural interplay on peptide hydrogen bonding, assembly, and mechanics. Networks formed from poly(β-benzyl-l-aspartate)-poly(dimethylsiloxane) copolymers covalently cross-linked with a triisocyanate yielded polyurea films with a globular-like morphology and parallel β-sheet secondary structures. The geometrical constraints imposed by the network led to an increase in peptide loading and ∼7x increase in Young's modulus while maintaining extensibility (∼160%). Thus, the interplay of physical and chemical bonds allowed for the modulation of resulting mechanical properties. This investigation provides a framework for the utilization of structural interplay and mechanical tuning in polymer-peptide hybrids, which offers a pathway for the design of future hybrid biomaterial systems.

  15. Sweet potato SPAP1 is a typical aspartic protease and participates in ethephon-mediated leaf senescence.

    Science.gov (United States)

    Chen, Hsien-Jung; Huang, Yu-Hsuan; Huang, Guan-Jhong; Huang, Shyh-Shyun; Chow, Te-Jin; Lin, Yaw-Huei

    2015-05-15

    Plant aspartic proteases are generally divided into three categories: typical, nucellin-like, and atypical aspartic proteases based on their gene and protein structures. In this report, a full-length cDNA SPAP1 was cloned from sweet potato leaves, which contained 1515 nucleotides (504 amino acids) and exhibited high amino acid sequence identity (ca. 51-72%) with plant typical aspartic proteases, including tomato LeAspP, potato StAsp, and wheat WAP2. SPAP1 also contained conserved DTG and DSG amino acid residues within its catalytic domain and plant specific insert (PSI) at the C-terminus. The cDNA corresponding to the mature protein (starting from the 66th to 311th amino acid residues) without PSI domain was constructed with pET30a expression vector for fusion protein and antibody production. RT-PCR and protein blot hybridization showed that SPAP1 expression level was the highest in L3 mature leaves, then gradually declined until L5 completely yellow leaves. Ethephon, an ethylene-releasing compound, also enhanced SPAP1 expression at the time much earlier than the onset of leaf senescence. Exogenous application of SPAP1 fusion protein promoted ethephon-induced leaf senescence, which could be abolished by pre-treatment of SPAP1 fusion protein with (a) 95 °C for 5 min, (b) aspartic protease inhibitor pepstatin A, and (c) anti-SPAP1 antibody, respectively. Exogenous SPAP1 fusion protein, whereas, did not significantly affect leaf senescence under dark. These data conclude that sweet potato SPAP1 is a functional typical aspartic protease and participates in ethephon-mediated leaf senescence. The SPAP1-promoted leaf senescence and its activity are likely not associated with the PSI domain. Interaction of ethephon-inducible components for effective SPAP1 promotion on leaf senescence is also suggested. Copyright © 2015 Elsevier GmbH. All rights reserved.

  16. Preoperative Aspartate Aminotransferase-to-Platelet Ratio Index Predicts Perioperative Liver-Related Complications Following Liver Resection for Colorectal Cancer Metastases

    DEFF Research Database (Denmark)

    Amptoulach, S.; Gross, G.; Sturesson, C.

    2017-01-01

    -related). In multivariate regression analysis, the aspartate aminotransferase-to-platelet ratio index was independently associated with liver-related complications (odds ratio: 1.149, p = 0.003) and perioperative liver failure (odds ratio: 1.155, p = 0.012). The latter was also true in the subcohort of patients...... with neoadjuvant chemotherapy (odds ratio: 1.157, p = 0.004) but not in those without such therapy (p = 0.062). The aspartate-to-alanine aminotransferase ratio was not related to liver-related complications (p = 0.929). The area under the receiver operating characteristics curve for the aspartate aminotransferase.......175) or steatosis (p = 0.173) in the nontumorous liver in surgical specimens. Conclusion: The preoperative aspartate aminotransferase-to-platelet ratio index, but not the aspartate-to-alanine aminotransferase ratio, predicts perioperative liver-related complications following hepatectomy due to colorectal cancer...

  17. Degradation of biomolecules in artificially and naturally aged teeth: implications for age estimation based on aspartic acid racemization and DNA analysis.

    Science.gov (United States)

    Dobberstein, Reimer C; Huppertz, Jan; von Wurmb-Schwark, Nicole; Ritz-Timme, Stefanie

    2008-08-06

    Postmortem teeth are the most stable structures, and can be used to gain different information (age estimation, genetic data). Over long postmortem intervals (PMI), degradation processes may alter the molecular integrity and thus affect the reliability of applied molecular methods. Whereas some knowledge on the degradation of biomolecules in bone during the PMI exists, data for teeth are lacking. In particular, the impact of degradation processes in dentine on age estimation based on aspartic acid racemization (AAR) cannot be estimated yet. Hence, the molecular stability of both collagen and DNA was analyzed systematically, and their impact on the reliability of age estimation based on AAR and genetic analyses was checked. Two hundred and ten human and 59 porcine teeth were heated (90 degrees C in water) to simulate collagen and DNA diagenesis; 14 naturally aged teeth (PMI: 3 days to 1700 years) were analyzed comparatively. Peptide patterns of cyanogen bromide (CNBr)-cleaved collagen were employed as a new approach to check the collagen integrity. In the same samples, collagen yields, amino acid compositions, AAR in different protein fractions, and DNA integrity were analyzed. In heated human and porcine teeth the collagen content declined during the heating experiment. The amino acid composition in human samples was collagen-like until 12 days of heating. In naturally aged teeth, the collagen yielded from 9.5 to 15%, and no discrepancy of amino acid composition to that of modern collagen was observed. Electrophoresis of CNBr-peptides showed an altered pattern in experimentally degraded samples from day 10 on; naturally aged collagen displayed the typical collagen pattern. AAR increased in all protein fractions with increasing duration of the heating experiment; naturally aged samples displayed a slow accumulation of AAR. DNA degraded progressively, and after 32 h of heat exposure no more DNA was detectable, whereas the amplification of nuclear and mitochondrial

  18. Tryptathionine bridges in peptide synthesis.

    Science.gov (United States)

    May, Jonathan P; Perrin, David M

    2007-01-01

    The tryptathionine linkage is a crosslink formed between tryptophan and cysteine. This feature is characteristic of the bicyclic peptides: the phallotoxins and the amatoxins. These peptides both bind to protein folds of their respective targets (F-actin and RNA pol II, respectively) with extremely high affinities. Studies on these peptides have shown that the tryptathionine crosslink is essential for this binding affinity. Tryptathionines have been investigated for many years and several syntheses exist for their formation. In this review, we report on the various methodologies employed in tryptathionine synthesis, and discuss some of the advantages and disadvantages associated with each of them. Copyright (c) 2007 Wiley Periodicals, Inc.

  19. Next generation natriuretic peptide measurement

    DEFF Research Database (Denmark)

    Hunter, Ingrid; Goetze, Jens P

    2012-01-01

    Plasma measurement of natriuretic peptides is a "must" for clinical laboratories. For the next generation measurement, the unraveling of the molecular complexity of the peptides points toward a more qualitative assessment, as the posttranslational processing also changes with disease. Changes...... in the molecular heterogeneity could in itself contain valuable information of clinical status, and the time seems right for industry and dedicated researchers in the field to get together and discuss the next generation natriuretic peptide measurement. In such an environment, new strategies can be developed...

  20. Targeting the Eph System with Peptides and Peptide Conjugates.

    Science.gov (United States)

    Riedl, Stefan J; Pasquale, Elena B

    2015-01-01

    Eph receptor tyrosine kinases and ephrin ligands constitute an important cell communication system that controls development, tissue homeostasis and many pathological processes. Various Eph receptors/ephrins are present in essentially all cell types and their expression is often dysregulated by injury and disease. Thus, the 14 Eph receptors are attracting increasing attention as a major class of potential drug targets. In particular, agents that bind to the extracellular ephrin-binding pocket of these receptors show promise for medical applications. This pocket comprises a broad and shallow groove surrounded by several flexible loops, which makes peptides particularly suitable to target it with high affinity and selectivity. Accordingly, a number of peptides that bind to Eph receptors with micromolar affinity have been identified using phage display and other approaches. These peptides are generally antagonists that inhibit ephrin binding and Eph receptor/ ephrin signaling, but some are agonists mimicking ephrin-induced Eph receptor activation. Importantly, some of the peptides are exquisitely selective for single Eph receptors. Most identified peptides are linear, but recently the considerable advantages of cyclic scaffolds have been recognized, particularly in light of potential optimization towards drug leads. To date, peptide improvements have yielded derivatives with low nanomolar Eph receptor binding affinity, high resistance to plasma proteases and/or long in vivo half-life, exemplifying the merits of peptides for Eph receptor targeting. Besides their modulation of Eph receptor/ephrin function, peptides can also serve to deliver conjugated imaging and therapeutic agents or various types of nanoparticles to tumors and other diseased tissues presenting target Eph receptors.

  1. Novel peptides with tyrosinase inhibitory activity

    NARCIS (Netherlands)

    Schurink, M.; Berkel, van W.J.H.; Wichers, H.J.; Boeriu, C.G.

    2007-01-01

    Tyrosinase inhibition by peptides may find its application in food, cosmetics or medicine. In order to identify novel tyrosinase inhibitory peptides, protein-based peptide libraries made by SPOT synthesis were used to screen for peptides that show direct interaction with tyrosinase. One of the

  2. Fmoc Solid-Phase Peptide Synthesis.

    Science.gov (United States)

    Hansen, Paul R; Oddo, Alberto

    2015-01-01

    Synthetic peptides are important as drugs and in research. Currently, the method of choice for producing these compounds is solid-phase peptide synthesis. In this nonspecialist review, we describe the scope and limitations of Fmoc solid-phase peptide synthesis. Furthermore, we provide a detailed protocol for Fmoc peptide synthesis.

  3. Endocrine roles of D-aspartic acid in the testis of lizard Podarcis s. sicula.

    Science.gov (United States)

    Raucci, F; D'Aniello, S; Di Fiore, M M

    2005-12-01

    In the lizard Podarcis s. sicula, a substantial amount of D-aspartate (D-Asp) is endogenous to the testis and shows cyclic changes of activity connected with sex hormone profiles during the annual reproductive phases. Testicular D-Asp content shows a direct correlation with testosterone titres and a reverse correlation with 17beta-estradiol titres. In vivo experiments, consisting of i.p. injections of 2.0 micromol/g body weight of D-Asp or other amino acids, in lizards collected during the three main phases of the reproductive cycle (pre-reproductive, reproductive and post-reproductive period), revealed that the testis can specifically take up and accumulate D-Asp alone. Moreover, this amino acid influences the synthesis of testosterone and 17beta-estradiol in all phases of the cycle. This phenomenon is particularly evident during the pre- and post-reproductive period, when endogenous testosterone levels observed in both testis and plasma were the lowest and 17beta-estradiol concentrations were the highest. D-Asp rapidly induces a fall in 17beta-estradiol and a rise in testosterone at 3 h post-injection in the testis and at 6 h post-injection in the blood. In vitro experiments show that testicular tissue converted L-Asp into D-Asp through an aspartate racemase. D-Asp synthesis was measured in all phases of the cycle, but was significantly higher during the reproductive period with a peak at pH 6.0. The exogenous D-Asp also induces a significant increase in the mitotic activity of the testis at 3 h (P proliferation cell nuclear antigen (PCNA). The effects of D-Asp on the testis appear to be specific since they were not seen in lizards injected with other D- or L-forms of amino acids with known excitatory effects on neurosecretion. Our results suggest a regulatory role for D-Asp in the steroido-genesis and spermatogenesis of the testis of the lizard Podarcis s. sicula.

  4. Poly(aspartic acid) with adjustable pH-dependent solubility.

    Science.gov (United States)

    Németh, Csaba; Gyarmati, Benjámin; Abdullin, Timur; László, Krisztina; Szilágyi, András

    2017-02-01

    Poly(aspartic acid) (PASP) derivatives with adjustable pH-dependent solubility were synthesized and characterized to establish the relationship between their structure and solubility in order to predict their applicability as a basic material for enteric coatings. Polysuccinimide, the precursor of PASP, was modified with short chain alkylamines, and the residual succinimide rings were subsequently opened to prepare the corresponding PASP derivatives. Study of the effect of the type and concentration of the side groups on the pH-dependent solubility of PASP showed that solubility can be adjusted by proper selection of the chemical structure. The Henderson-Hasselbalch (HH) and the extended HH equations were used to describe the pH-dependent solubility of the polymers quantitatively. The estimate provided by the HH equation is poor, but an accurate description of the pH-dependent solubility can be found with the extended HH equation. The dissolution rate of a polymer film prepared from a selected PASP derivative was determined by fluorescence marking. The film dissolved rapidly when the pH was increased above its pK a . Cellular viability tests show that PASP derivatives are non-toxic to a human cell line. These polymers are thus of great interest as starting materials for enteric coatings. Poly(amino acid) type biocompatible polymers were synthesized for future use as pharmaceutical film coatings. To this end, we tailored the pH-dependent solubility of poly(aspartic acid) (PASP). It was found that both the solubility and the pK a values of the modified PASP depended strongly on composition. Fluorescent marking was used to characterize the dissolution of a chosen PASP derivative. In acidic media only a negligible amount of the polymer dissolved, but dissolution was very fast and complete at the pH values that prevail in the small intestine. As a consequence, enteric coatings based on such PASP derivatives may be used for drug delivery in the gastrointestinal tract

  5. Structures of self-assembled amphiphilic peptide-heterodimers: effects of concentration, pH, temperature and ionic strength

    KAUST Repository

    Luo, Zhongli

    2010-01-01

    The amphiphilic double-tail peptides AXG were studied regarding secondary structure and self-assembly in aqueous solution. The two tails A = Ala 6 and G = Gly6 are connected by a central pair X of hydrophilic residues, X being two aspartic acids in ADG, two lysines in AKG and two arginines in ARG. The peptide AD (Ala6Asp) served as a single-tail reference. The secondary structure of the four peptides was characterized by circular dichroism spectroscopy under a wide range of peptide concentrations (0.01-0.8 mM), temperatures (20-98 °C), pHs (4-9.5) and ionic strengths. In salt-free water both ADG and AD form a β-sheet type of structure at high concentration, low pH and low temperature, in a peptide-peptide driven assembly of individual peptides. The transition has a two-state character for ADG but not for AD, which indicates that the added tail in ADG makes the assembly more cooperative. By comparison the secondary structures of AKG and ARG are comparatively stable over the large range of conditions covered. According to dynamic light scattering the two-tail peptides form supra-molecular aggregates in water, but high-resolution AFM-imaging indicate that ordered (self-assembled) structures are only formed when salt (0.1 M NaCl) is added. Since the CD-studies indicate that the NaCl has only a minor effect on the peptide secondary structure we propose that the main role of the added salt is to screen the electrostatic repulsion between the peptide building blocks. According to the AFM images ADG and AKG support a correlation between nanofibers and a β-sheet or unordered secondary structure, whereas ARG forms fibers in spite of lacking β-sheet structure. Since the AKG and ARG double-tail peptides self-assemble into distinct nanostructures while their secondary structures are resistant to environment factors, these new peptides show potential as robust building blocks for nano-materials in various medical and nanobiotechnical applications. © 2010 The Royal Society

  6. A Fluorescence-Based High-Throughput Coupled Enzymatic Assay for Quantitation of Isoaspartate in Proteins and Peptides.

    Science.gov (United States)

    Puri, Aastha; Quan, Yong; Narang, Ajit S; Adams, Monica; Gandhi, Rajesh; Nashine, Vishal C

    2017-04-01

    Formation of isoaspartate (IsoAsp) from spontaneous asparagine (Asn) deamidation or aspartate (Asp) isomerization is one of the most common non-enzymatic pathways of chemical degradation of protein and peptide pharmaceuticals. Rapid quantitation of IsoAsp formation can enable rank-ordering of potential drug candidates, mutants, and formulations as well as support shelf life prediction and stability requirements. A coupled enzymatic fluorescence-based IsoAsp assay (CEFIA) was developed as a high-throughput method for quantitation of IsoAsp in peptides and proteins. In this note, application of this method to two therapeutic candidate proteins with distinct structural scaffolds is described. In addition, the results obtained with this method are compared to those from conventional assays.

  7. The Pig PeptideAtlas

    DEFF Research Database (Denmark)

    Hesselager, Marianne O.; Codrea, Marius C.; Sun, Zhi

    2016-01-01

    underrepresented in existing repositories. We here present a significantly improved build of the Pig PeptideAtlas, which includes pig proteome data from 25 tissues and three body fluid types mapped to 7139 canonical proteins. The content of the Pig PeptideAtlas reflects actively ongoing research within...... the veterinary proteomics domain, and this article demonstrates how the expression of isoform-unique peptides can be observed across distinct tissues and body fluids. The Pig PeptideAtlas is a unique resource for use in animal proteome research, particularly biomarker discovery and for preliminary design of SRM...... assays, which are equally important for progress in research that supports farm animal production and veterinary health, as for developing pig models with relevance to human health research....

  8. Structural Characterization of Peptide Antibodies

    DEFF Research Database (Denmark)

    Chailyan, Anna; Marcatili, Paolo

    2015-01-01

    can be modified to obtain desired properties or conformation, tagged for purification, isotopically labeled for protein quantitation or conjugated to immunogens for antibody production. The antibodies that bind to these peptides represent an invaluable tool for biological research and discovery...

  9. Therapeutical Potential of Venom Peptides

    Directory of Open Access Journals (Sweden)

    İlker Kelle

    2006-01-01

    Full Text Available The term of pharmazooticals is known as a few amount of drugs derived from natural sources such as plants, venomous species of snakes, spiders, scorpions, frogs, lizards and cone snails. Peptide components of venoms are directed against wide variety of pharmacological targets such as ion channels and receptors. At the beginning, a number of these peptides have been used in experimental studies for defining the physiological, biochemical and immunological activities of organisms like mammalians. In recent studies, it has been shown that venom peptides can be valuable in treatment of acute and chronic pain, autoimmune and cardiovascular diseases, neurological disorders and chronic inflammatory and tumoral processes. Therefore particularly in clinical approaches, these peptide molecules or their synthetic analogues are considered as alternative agents that can be used instead of classical drugs for many clinical disorders due to their potent activity besides very few side effects.

  10. Hemolytic Activity of Antimicrobial Peptides.

    Science.gov (United States)

    Oddo, Alberto; Hansen, Paul R

    2017-01-01

    For antimicrobial peptides to be interesting for systemic applications, they must show low toxicity against erythrocytes. In this chapter, we describe a protocol for measuring the ability of AMPs to lyse human red blood cells, using melittin as positive control.

  11. Moonlighting peptides with emerging function.

    Directory of Open Access Journals (Sweden)

    Jonathan G Rodríguez Plaza

    Full Text Available Hunter-killer peptides combine two activities in a single polypeptide that work in an independent fashion like many other multi-functional, multi-domain proteins. We hypothesize that emergent functions may result from the combination of two or more activities in a single protein domain and that could be a mechanism selected in nature to form moonlighting proteins. We designed moonlighting peptides using the two mechanisms proposed to be involved in the evolution of such molecules (i.e., to mutate non-functional residues and the use of natively unfolded peptides. We observed that our moonlighting peptides exhibited two activities that together rendered a new function that induces cell death in yeast. Thus, we propose that moonlighting in proteins promotes emergent properties providing a further level of complexity in living organisms so far unappreciated.

  12. Biomedical Applications of Organometal-Peptide Conjugates

    Science.gov (United States)

    Metzler-Nolte, Nils

    Peptides are well suited as targeting vectors for the directed delivery of metal-based drugs or probes for biomedical investigations. This chapter describes synthetic strategies for the preparation of conjugates of medically interesting peptides with covalently bound metal complexes. Peptides that were used include neuropeptides (enkephalin, neuropeptide Y, neurotensin), uptake peptides (TAT and poly-Arg), and intracellular localization sequences. To these peptides, a whole variety of transition metal complexes has been attached in recent years by solid-phase peptide synthesis (SPPS) techniques. The metal complex can be attached to the peptide on the resin as part of the SPPS scheme. Alternatively, the metal complex may be attached to the peptide as a postsynthetic modification. Advantages as well as disadvantages for either strategy are discussed. Biomedical applications include radiopharmaceutical applications, anticancer and antibacterial activity, metal-peptide conjugates as targeted CO-releasing molecules, and metal-peptide conjugates in biosensor applications.

  13. Production and characterization of peptide antibodies

    DEFF Research Database (Denmark)

    Trier, Nicole Hartwig; Hansen, P. R.; Houen, G.

    2012-01-01

    Proteins are effective immunogens for generation of antibodies. However, occasionally the native protein is known but not available for antibody production. In such cases synthetic peptides derived from the native protein are good alternatives for antibody production. These peptide antibodies...... are powerful tools in experimental biology and are easily produced to any peptide of choice. A widely used approach for production of peptide antibodies is to immunize animals with a synthetic peptide coupled to a carrier protein. Very important is the selection of the synthetic peptide, where factors......, including solid-phase peptide-carrier conjugation and peptide-carrier conjugation in solution. Upon immunization, adjuvants such as Al(OH)(3) are added together with the immunogenic peptide-carrier conjugate, which usually leads to high-titred antisera. Following immunization and peptide antibody...

  14. The greening of peptide synthesis

    OpenAIRE

    Lawrenson, Stefan B.; Arav, Roy; North, Michael

    2017-01-01

    The synthesis of peptides by amide bond formation between suitably protected amino acids is a fundamental part of the drug discovery process. However, the required coupling and deprotection reactions are routinely carried out in dichloromethane and DMF, both of which have serious toxicity concerns and generate waste solvent which constitutes the vast majority of the waste generated during peptide synthesis. In this work, propylene carbonate has been shown to be a green polar aprotic solvent w...

  15. Material Binding Peptides for Nanotechnology

    Directory of Open Access Journals (Sweden)

    Urartu Ozgur Safak Seker

    2011-02-01

    Full Text Available Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.

  16. Matrix-assisted peptide synthesis on nanoparticles.

    Science.gov (United States)

    Khandadash, Raz; Machtey, Victoria; Weiss, Aryeh; Byk, Gerardo

    2014-09-01

    We report a new method for multistep peptide synthesis on polymeric nanoparticles of differing sizes. Polymeric nanoparticles were functionalized via their temporary embedment into a magnetic inorganic matrix that allows multistep peptide synthesis. The matrix is removed at the end of the process for obtaining nanoparticles functionalized with peptides. The matrix-assisted synthesis on nanoparticles was proved by generating various biologically relevant peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  17. Enhancement of Pulmozyme activity in purulent sputum by combination with poly-aspartic acid or gelsolin.

    Science.gov (United States)

    Bucki, Robert; Cruz, Katrina; Pogoda, Katarzyna; Eggert, Ashley; Chin, LiKang; Ferrin, Marianne; Imbesi, Giovanna; Hadjiliadis, Denis; Janmey, Paul A

    2015-09-01

    DNase (Pulmozyme) effectiveness in cystic fibrosis treatment is in some cases limited by its inability to access DNA trapped within bundles in highly viscous fluids that also contain actin. Dissociating DNA-containing bundles using actin depolymerizing agents and polyanions has potential to increase DNase efficacy. Fluorescence measurements of YOYO-1 and a rheological creep-recovery test quantified DNA content and viscoelasticity in 150 sputum samples from adult CF patients and their susceptibility to fluidization by DNase1, alone and in combination with gelsolin and poly-aspartate (p-Asp). Fluidization of sputum by these agents is compared to their capacity to increase antibacterial activity in sputum, measured using a luminescent Pseudomonas aeruginosa strain and a bacterial killing assay. The polyanion p-Asp (1-50 μg/g of sputum), the actin severing protein gelsolin (10-90 μg/g) and their combination enhance the ability of DNase 1 to increase the abnormally low mechanical compliance of CF sputum and to promote bacterial killing in sputum by colistin and tobramycin, two antibiotics commonly used to treat CF. Addition of low concentrations of p-ASP or gelsolin can increase the therapeutic value of Pulmozyme (DNase 1). Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  18. Subfield-specific loss of hippocampal N-acetyl aspartate in temporal lobe epilepsy.

    Science.gov (United States)

    Vielhaber, Stefan; Niessen, Heiko G; Debska-Vielhaber, Grazyna; Kudin, Alexei P; Wellmer, Jörg; Kaufmann, Jörn; Schönfeld, Mircea Ariel; Fendrich, Robert; Willker, Wieland; Leibfritz, Dieter; Schramm, Johannes; Elger, Christian E; Heinze, Hans-Jochen; Kunz, Wolfram S

    2008-01-01

    In patients with mesial temporal lobe epilepsy (MTLE) it remains an unresolved issue whether the interictal decrease in N-acetyl aspartate (NAA) detected by proton magnetic resonance spectroscopy ((1)H-MRS) reflects the epilepsy-associated loss of hippocampal pyramidal neurons or metabolic dysfunction. To address this problem, we applied high-resolution (1)H-MRS at 14.1 Tesla to measure metabolite concentrations in ex vivo tissue slices from three hippocampal subfields (CA1, CA3, dentate gyrus) as well as from the parahippocampal region of 12 patients with MTLE. In contrast to four patients with lesion-caused MTLE, we found a large variance of NAA concentrations in the individual hippocampal regions of patients with Ammon's horn sclerosis (AHS). Specifically, in subfield CA3 of AHS patients despite of a moderate preservation of neuronal cell densities the concentration of NAA was significantly lowered, while the concentrations of lactate, glucose, and succinate were elevated. We suggest that these subfield-specific alterations of metabolite concentrations in AHS are very likely caused by impairment of mitochondrial function and not related to neuronal cell loss. A subfield-specific impairment of energy metabolism is the probable cause for lowered NAA concentrations in sclerotic hippocampi of MTLE patients.

  19. N-Methyl D-Aspartate Receptor Antagonist Kynurenic Acid affects Human Cortical Development

    Directory of Open Access Journals (Sweden)

    Inseyah Bagasrawala

    2016-09-01

    Full Text Available Kynurenic acid (KYNA, a neuroactive metabolite of tryptophan degradation, acts as an endogenous N-methyl-D-aspartate receptor (NMDAR antagonist. Elevated levels of KYNA have been observed in pregnant women after viral infections and are considered to play a role in neurodevelopmental disorders. However, the consequences of KYNA-induced NMDAR blockade in human cortical development still remain elusive. To study the potential impact of KYNA on human neurodevelopment, we used an in vitro system of multipotent cortical progenitors, i.e., radial glia cells (RGCs, enriched from human cerebral cortex at mid-gestation (16-19 gestational weeks. KYNA treatment significantly decreased RGCs proliferation and survival by antagonizing NMDAR. This alteration resulted in a reduced number of cortical progenitors and neurons while number and activation of astrocytes increased. KYNA treatment reduced differentiation of RGCs into GABAergic neurons, while differentiation into glutamatergic neurons was relatively spared. Furthermore, in mixed cortical cultures KYNA triggered an inflammatory response as evidenced by increased levels of the pro-inflammatory cytokine IL-6. In conclusion, elevated levels of KYNA play a significant role in human RGC fate determination by antagonizing NMDARs and by activating an inflammatory response. The altered cell composition observed in cell culture following exposure to elevated KYNA levels suggests a mechanism for impairment of cortical circuitry formation in the fetal brain after viral infection, as seen in neurodevelopmental disorders such as schizophrenia.

  20. Functional plasticity of the N-methyl-d-aspartate receptor in differentiating human erythroid precursor cells.

    Science.gov (United States)

    Hänggi, Pascal; Telezhkin, Vsevolod; Kemp, Paul J; Schmugge, Markus; Gassmann, Max; Goede, Jeroen S; Speer, Oliver; Bogdanova, Anna

    2015-06-15

    Calcium signaling is essential to support erythroid proliferation and differentiation. Precise control of the intracellular Ca(2+) levels in erythroid precursor cells (EPCs) is afforded by coordinated expression and function of several cation channels, including the recently identified N-methyl-d-aspartate receptor (NMDAR). Here, we characterized the changes in Ca(2+) uptake and electric currents mediated by the NMDARs occurring during EPC differentiation using flow cytometry and patch clamp. During erythropoietic maturation, subunit composition and properties of the receptor changed; in proerythroblasts and basophilic erythroblasts, fast deactivating currents with high amplitudes were mediated by the GluN2A subunit-dominated receptors, while at the polychromatic and orthochromatic erythroblast stages, the GluN2C subunit was getting more abundant, overriding the expression of GluN2A. At these stages, the currents mediated by the NMDARs carried the features characteristic of the GluN2C-containing receptors, such as prolonged decay time and lower conductance. Kinetics of this switch in NMDAR properties and abundance varied markedly from donor to donor. Despite this variability, NMDARs were essential for survival of EPCs in any subject tested. Our findings indicate that NMDARs have a dual role during erythropoiesis, supporting survival of polychromatic erythroblasts and contributing to the Ca(2+) homeostasis from the orthochromatic erythroblast stage to circulating red blood cells. Copyright © 2015 the American Physiological Society.

  1. N-methyl-D-aspartate (NMDA) impairs myogenesis in C2C12 cells.

    Science.gov (United States)

    Auh, Q-SChick; Park, Kyung-Ran; Lee, Myeong-Ok; Hwang, Mi-Jin; Kang, Soo-Kyung; Hong, Jung-Pyo; Yun, Hyung-Mun; Kim, Eun-Cheol

    2017-09-01

    N-methyl-d-aspartate (NMDA) is expressed in sensory neurons and plays important roles in peripheral pain mechanisms. The aim of this study was to examine the effects and molecular mechanisms of NMDA on C2C12 myoblast proliferation and differentiation. Cytotoxicity and differentiation were examined by the MTT assay, reverse transcription-polymerase chain reaction, and immunofluorescence. NMDA had no cytotoxicity (10-500 μM) and inhibited myoblastic differentiation of C2C12 cells, as assessed by F-actin immunofluorescence and levels of mRNAs encoding myogenic markers such as myogenin and myosin heavy-chain 2. It inhibited phosphorylation of mammalian target of rapamycin (mTOR) by inactivating mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38. It induced reactive oxygen species production. Furthermore, NMDA-suppressed expression of F-actin was reversed by adding the antioxidant N-acetylcysteine. Collectively, these results indicate that NMDA impairs myogenesis or myogenic differentiation in C2C12 cells through the mTOR/MAPK signaling pathways and may lead to skeletal muscle degeneration. Muscle Nerve 56: 510-518, 2017. © 2016 Wiley Periodicals, Inc.

  2. Evaluation of poly (aspartic acid sodium salt) as a draw solute for forward osmosis.

    Science.gov (United States)

    Gwak, Gimun; Jung, Bokyung; Han, Sungsoo; Hong, Seungkwan

    2015-09-01

    Poly (aspartic acid sodium salt) (PAspNa) was evaluated for its potential as a novel draw solute in forward osmosis (FO). The inherent advantages of PAspNa, such as good water solubility, high osmotic pressure, and nontoxicity, were first examined through a series of physicochemical analyses and atomic-scale molecular dynamics simulations. Then, lab-scale FO tests were performed to evaluate its suitability in practical processes. Compared to other conventional inorganic solutes, PAspNa showed comparable water flux but significantly lower reverse solute flux, demonstrating its suitability as a draw solute. Moreover, fouling experiments using synthetic wastewater as a feed solution demonstrated that PAspNa reversely flowed to the feed side reduced inorganic scaling on the membrane active layer. The recyclability of PAspNa was studied using both nanofiltration (NF) and membrane distillation (MD) processes, and the results exhibited its ease of recovery. This research reported the feasibility and applicability of FO-NF or FO-MD processes using PAspNa for wastewater reclamation and brackish water desalination. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review

    Directory of Open Access Journals (Sweden)

    Farzad Roshanzamir

    2017-08-01

    Full Text Available Background: D-Aspartic acid (D-Asp is in invertebrate and vertebrate neuroendocrine tissues, where it carries out important physiological functions. Recently, it has been reported that D-Asp is involved in the synthesis and release of testosterone and is assumed can be used as a testosterone booster for infertile men, and by athletes to increase muscle mass and strength. Objective: The aim of this review is to summarize available evidence related to the effects of D-Asp on serum testosterone levels. Materials and Methods: We conducted a systematic review of all type studies, which evaluated the effect of the D-Asp on blood testosterone including published papers until October 2015, using PubMed, ISI Web of Science, ProQuest and Scopus database. Results: With 396 retrieved records, 23 animal studies and 4 human studies were included. In vivo and in vitro animal studies revealed the effect of D-Asp depending on species, sex and organ-specific. Our results showed that exogenous D-Asp enhances testosterone levels in male animal’s studies, whereas studies in human yielded inconsistent results. The evidence for this association in man is still sparse, mostly because of limited number and poor quality studies. Conclusion: There is an urgent need for more and well-designed human clinical trials with larger sample sizes and longer duration to investigate putative effects of D-Asp on testosterone concentrations.

  4. Kinetic simulation of malate-aspartate and citrate-pyruvate shuttles in association with Krebs cycle.

    Science.gov (United States)

    Korla, Kalyani; Vadlakonda, Lakshmipathi; Mitra, Chanchal K

    2015-01-01

    In the present work, we have kinetically simulated two mitochondrial shuttles, malate-aspartate shuttle (used for transferring reducing equivalents) and citrate-pyruvate shuttle (used for transferring carbon skeletons). However, the functions of these shuttles are not limited to the points mentioned above, and they can be used in different arrangements to meet different cellular requirements. Both the shuttles are intricately associated with Krebs cycle through the metabolites involved. The study of this system of shuttles and Krebs cycle explores the response of the system in different metabolic environments. Here, we have simulated these subsets individually and then combined them to study the interactions among them and to bring out the dynamics of these pathways in focus. Four antiports and a pyruvate pump were modelled along with the metabolic reactions on both sides of the inner mitochondrial membrane. Michaelis-Menten approach was extended for deriving rate equations of every component of the system. Kinetic simulation was carried out using ordinary differential equation solver in GNU Octave. It was observed that all the components attained steady state, sooner or later, depending on the system conditions. Progress curves and phase plots were plotted to understand the steady state behaviour of the metabolites involved. A comparative analysis between experimental and simulated data show fair agreement thus validating the usefulness and applicability of the model.

  5. Lithium citrate reduces excessive intra-cerebral N-acetyl aspartate in Canavan disease.

    Science.gov (United States)

    Assadi, Mitra; Janson, Christopher; Wang, Dah-Jyuu; Goldfarb, Olga; Suri, Neeti; Bilaniuk, Larissa; Leone, Paola

    2010-07-01

    Our group has previously reported the first clinical application of lithium in a child affected by Canavan disease. In this study, we aimed to assess the effects of lithium on N-acetyl aspartate (NAA) as well as other end points in a larger cohort. Six patients with clinical, laboratory and genetic confirmation of Canavan disease were recruited and underwent treatment with lithium. The battery of safety and efficacy testing performed before and after sixty days of treatment included Gross Motor Function Testing (GMFM), Magnetic Resonance Imaging (MRI) Proton Magnetic Spectroscopy (H-MRS) as well as blood work. The medication was safe without any clinical or laboratory evidence for toxicity. Parental reports indicated improvement in alertness and social interactions. GMFM did not show statistically significant improvement in motor development. H-MRS documented an overall drop in NAA which was statistically significant in the basal ganglia. T1 measurements recorded on MRI studies suggested a mild improvement in myelination in the frontal white matter after treatment. Diffusion Tensor Imaging was available in two patients and suggested micro-structural improvement in the corpus callosum. The results suggest that lithium administration may be beneficial in patients with Canavan disease. Copyright (c) 2009 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  6. Aspartate aminotransferase is potently inhibited by copper complexes: Exploring copper complex-binding proteome.

    Science.gov (United States)

    Jia, Yuqi; Lu, Liping; Yuan, Caixia; Feng, Sisi; Zhu, Miaoli

    2017-05-01

    Recent researches indicated that a copper complex-binding proteome that potently interacted with copper complexes and then influenced cellular metabolism might exist in organism. In order to explore the copper complex-binding proteome, a copper chelating ion-immobilized affinity chromatography (Cu-IMAC) column and mass spectrometry were used to separate and identify putative Cu-binding proteins in primary rat hepatocytes. A total of 97 putative Cu-binding proteins were isolated and identified. Five higher abundance proteins, aspartate aminotransferase (AST), malate dehydrogenase (MDH), catalase (CAT), calreticulin (CRT) and albumin (Alb) were further purified using a SP-, and (or) Q-Sepharose Fast Flow column. The interaction between the purified proteins and selected 11 copper complexes and CuCl2 was investigated. The enzymes inhibition tests demonstrated that AST was potently inhibited by copper complexes while MDH and CAT were weakly inhibited. Schiff-based copper complexes 6 and 7 potently inhibited AST with the IC50 value of 3.6 and 7.2μM, respectively and exhibited better selectivity over MDH and CAT. Fluorescence titration results showed the two complexes tightly bound to AST with binding constant of 3.89×10(6) and 3.73×10(6)M(-1), respectively and a stoichiometry ratio of 1:1. Copper complex 6 was able to enter into HepG2 cells and further inhibit intracellular AST activity. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. N-Methyl-d-Aspartate Receptor Antibodies in Herpes Simplex Encephalitis

    Science.gov (United States)

    Prüss, Harald; Finke, Carsten; Höltje, Markus; Hofmann, Joerg; Klingbeil, Christine; Probst, Christian; Borowski, Kathrin; Ahnert-Hilger, Gudrun; Harms, Lutz; Schwab, Jan M.; Ploner, Christoph J.; Komorowski, Lars; Stoecker, Winfried; Dalmau, Josep; Wandinger, Klaus-Peter

    2013-01-01

    Objective To determine the presence and kinetics of antibodies against synaptic proteins in patients with herpes simplex virus encephalitis (HSE). Methods Retrospective analysis of 44 patients with polymerase chain reaction-proven HSE for the presence of a large panel of onconeuronal and synaptic receptor antibodies. The effect of patients’ serum was studied in cultures of primary mouse hippocampal neurons. Results N-Methyl-d-aspartate receptor (NMDAR) antibodies of the immunoglobulin (Ig) subtypes IgA, IgG, or IgM were detected in 13 of 44 patients (30%) in the course of HSE, suggesting secondary autoimmune mechanisms. NMDAR antibodies were often present at hospital admission, but in some patients developed after the first week of HSE. Antibody-positive sera resulted in downregulation of synaptic marker proteins in hippocampal neurons. Interpretation Some patients with HSE develop IgA, IgG, or IgM autoantibodies against NMDAR. Sera from these patients alter the density of neuronal synaptic markers, suggesting a potential pathogenic disease-modifying effect. These findings have implications for the understanding of autoimmunity in infectious diseases, and prospective studies should reveal whether the subgroup of patients with HSE and NMDAR antibodies may benefit from immunotherapy. PMID:23280840

  8. Structural Dynamics of the Glycine-binding Domain of the N-Methyl-d-Aspartate Receptor*

    Science.gov (United States)

    Dolino, Drew M.; Cooper, David; Ramaswamy, Swarna; Jaurich, Henriette; Landes, Christy F.; Jayaraman, Vasanthi

    2015-01-01

    N-Methyl-d-aspartate receptors mediate the slow component of excitatory neurotransmission in the central nervous system. These receptors are obligate heteromers containing glycine- and glutamate-binding subunits. The ligands bind to a bilobed agonist-binding domain of the receptor. Previous x-ray structures of the glycine-binding domain of NMDA receptors showed no significant changes between the partial and full agonist-bound structures. Here we have used single molecule fluorescence resonance energy transfer (smFRET) to investigate the cleft closure conformational states that the glycine-binding domain of the receptor adopts in the presence of the antagonist 5,7-dichlorokynurenic acid (DCKA), the partial agonists 1-amino-1-cyclobutanecarboxylic acid (ACBC) and l-alanine, and full agonists glycine and d-serine. For these studies, we have incorporated the unnatural amino acid p-acetyl-l-phenylalanine for specific labeling of the protein with hydrazide derivatives of fluorophores. The single molecule fluorescence resonance energy transfer data show that the agonist-binding domain can adopt a wide range of cleft closure states with significant overlap in the states occupied by ligands of varying efficacy. The difference lies in the fraction of the protein in a more closed-cleft form, with full agonists having a larger fraction in the closed-cleft form, suggesting that the ability of ligands to select for these states could dictate the extent of activation. PMID:25404733

  9. Structural dynamics of the glycine-binding domain of the N-methyl-D-aspartate receptor.

    Science.gov (United States)

    Dolino, Drew M; Cooper, David; Ramaswamy, Swarna; Jaurich, Henriette; Landes, Christy F; Jayaraman, Vasanthi

    2015-01-09

    N-Methyl-D-aspartate receptors mediate the slow component of excitatory neurotransmission in the central nervous system. These receptors are obligate heteromers containing glycine- and glutamate-binding subunits. The ligands bind to a bilobed agonist-binding domain of the receptor. Previous x-ray structures of the glycine-binding domain of NMDA receptors showed no significant changes between the partial and full agonist-bound structures. Here we have used single molecule fluorescence resonance energy transfer (smFRET) to investigate the cleft closure conformational states that the glycine-binding domain of the receptor adopts in the presence of the antagonist 5,7-dichlorokynurenic acid (DCKA), the partial agonists 1-amino-1-cyclobutanecarboxylic acid (ACBC) and L-alanine, and full agonists glycine and D-serine. For these studies, we have incorporated the unnatural amino acid p-acetyl-L-phenylalanine for specific labeling of the protein with hydrazide derivatives of fluorophores. The single molecule fluorescence resonance energy transfer data show that the agonist-binding domain can adopt a wide range of cleft closure states with significant overlap in the states occupied by ligands of varying efficacy. The difference lies in the fraction of the protein in a more closed-cleft form, with full agonists having a larger fraction in the closed-cleft form, suggesting that the ability of ligands to select for these states could dictate the extent of activation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. N-methyl-D-aspartate/phencyclidine receptor complex of rat forebrain: Purification and biochemical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ikin, A.F.; Kloog, Y.; Sokolovsky, M. (Tel Aviv Univ. (Israel))

    1990-03-06

    The N-methyl-D-aspartate NMDA/phencyclidine (PCP) receptor from rat forebrain was solubilized with sodium cholate and purified by affinity chromatography on amino-PCP-agarose. A 3,700-fold purification was achieved. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and dithiothreitol revealed four major bands of M{sub r} 67,000, 57,000, 46,000, and 33,000. ({sup 3}H)Azido-PCP was irreversibly incorporated into each of these bands after UV irradiation. The dissociation constant (K{sub d}) of (1-(2-thienyl)cyclohexyl)piperidine (({sup 3}H)TCP) binding to the purified NMDA/PCP receptor was 120 nM. The maximum specific binding (B{sub max}) for ({sup 3}H)TCP binding was 3.3 nmol/mg of protein. The pharmacological profile of the purified receptor complex was similar to that of the membranal and soluble receptors. The binding of ({sup 3}H)TCP to the purified receptor was modulated by the NMDA receptor ligands glutamate, glycine, and NMDA.

  11. Strongyloides papillosus: changes in transcript levels of lysozyme and aspartic protease 2 in percutaneously migrated larvae.

    Science.gov (United States)

    Biewener, Valerie; Welz, Claudia; Khumpool, Grisada; Küttler, Ulla; Schnieder, Thomas

    2012-09-01

    The infection of the host is the crucial event in the life-cycle of parasites. To understand the molecular mechanisms of this important step, different methods are used in present studies. For analysis of changes in transcript levels the most sensitive method is the quantitative real-time PCR (qPCR). For an accurate analysis the evaluation of a set of adequate reference genes is necessary. The present study aimed to analyse the transcriptional levels of two genes of interest, the putative aspartic protease Spa-asp-2 and the putative lysozyme Spa-lys, in infective, free-living larvae of Strongyloides papillosus at different ages and from long-term and short-term infections and percutaneously migrated ("parasitic") larvae. Percutaneously migrated larvae were collected using the PERL chamber system and ovine skin in vitro. Reference genes identified as most suitable for transcriptional analysis according to geNorm analysis were genes for the eukaryotic translation elongation factor 1 alpha (Spa-eft-2), actin variation 2 (Spa-act-v2) and beta tubulin (Spa-tbb-1). Transcriptional analysis of the genes in percutaneously migrated larvae showed an upregulation of Spa-asp-2, while Spa-lys was downregulated. Data from the presented study provide a first glance into the changes of transcript levels of S. papillosus induced by percutaneous migration. Copyright © 2012. Published by Elsevier Inc.

  12. Column chromatography and immunoassay compared for measuring the isoenzymes of aspartate aminotransferase in serum.

    Science.gov (United States)

    Sampson, E J; Hannon, W H; McKneally, S S; McKenzie, C; Miller, S A; Whitner, V S; Burtis, C A

    1979-10-01

    We compare a column-chromatographic method and a homogeneous immunoassay method for separately measuring the mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase. Analytical recovery for the two methods averaged 102% (SD, 2%) and 103% (SD, 4%), respectively, for 11 pools prepared by adding the purified isoenzymes to serum and 102% (SD 8.9%) and 89% (SD, 8.1%) for 26 unaltered specimens of human serum. In comparing the results of the immunoassay method (y) to the chromatographic method (x), our measurements agreed closely for the mitochondrial (y = 0.947 X + 7, r = 0.9991, standard error of estimate = 2.9 U/L) and cytoplasmic (y = 0.92x-6, r = 0.9995, standard error of estimate = 2.1 U/L) isoenzymes in pools prepared from the purified isoenzymes. Similar measurements of the 26 human serum specimens yielded the following results for least-squares evaluation; cytoplasmic isoenzyme y = 1.03x-11, r = 0.994, and standard error of estimate = 6.0 U/L; mitochondrial isoenzyme y = 0.75x+0, r = 0.927, and standard error of estimate = 3.9 U/L.

  13. Purification and characterization of a milk-clotting aspartic proteinase from globe artichoke (Cynara scolymus L.).

    Science.gov (United States)

    Llorente, Berta E; Brutti, Cristina B; Caffini, Néstor O

    2004-12-29

    The study of proteinase expression in crude extracts from different organs of the globe artichoke (Cynara scolymus L.) disclosed that enzymes with proteolytic and milk-clotting activity are mainly located in mature flowers. Maximum proteolytic activity was recorded at pH 5.0, and inhibition studies showed that only pepstatin, specific for aspartic proteinases, presented a significant inhibitory effect. Such properties, in addition to easy enzyme inactivation by moderate heating, make this crude protease extract potentially useful for cheese production. Adsorption with activated carbon, together with anion exchange and affinity chromatography, led to the isolation of a heterodimeric milk-clotting proteinase consisting of 30- and 15-kDa subunits. MALDI-TOF MS of the 15-kDa chain determined a 15.358-Da mass, and the terminal amino sequence presented 96% homology with the smaller cardosin A subunit. The amino terminal sequence of the 30-kDa chain proved to be identical to the larger cardosin A subunit. Electrophoresis evidenced proteinase self-processing that was confirmed by immunoblots presenting 62-, 30-, and 15-kDa bands.

  14. Selective Impairment of Spatial Cognition Caused by Autoantibodies to the N-Methyl-d-Aspartate Receptor

    Directory of Open Access Journals (Sweden)

    Eric H. Chang

    2015-07-01

    Full Text Available Patients with systemic lupus erythematosus (SLE experience cognitive abnormalities in multiple domains including processing speed, executive function, and memory. Here we show that SLE patients carrying antibodies that bind DNA and the GluN2A and GluN2B subunits of the N-methyl-d-aspartate receptor (NMDAR, termed DNRAbs, displayed a selective impairment in spatial recall. Neural recordings in a mouse model of SLE, in which circulating DNRAbs penetrate the hippocampus, revealed that CA1 place cells exhibited a significant expansion in place field size. Structural analysis showed that hippocampal pyramidal cells had substantial reductions in their dendritic processes and spines. Strikingly, these abnormalities became evident at a time when DNRAbs were no longer detectable in the hippocampus. These results suggest that antibody-mediated neurocognitive impairments may be highly specific, and that spatial cognition may be particularly vulnerable to DNRAb-mediated structural and functional injury to hippocampal cells that evolves after the triggering insult is no longer present.

  15. Anti-N-methyl-D-aspartate receptor encephalitis: three cases report and review of literature

    Directory of Open Access Journals (Sweden)

    Guan-en ZHOU

    2014-07-01

    Full Text Available Objective To study the clinical and laboratory features and diagnosis of the patient with anti-N-methyl-D-aspartate receptor (NMDAR encephalitis.  Methods The data of clinical features, laboratory findings, and radiological manifestations of 3 patients with anti-NMDAR encephalitis were reviewed and analyzed. Results Of the 3 patients, 2 were male and one was female. The age was from 33 to 34 years (33.30 years on average. Main symptoms included headache in 2 cases, psychiatric symptoms and speech disorder in 3 cases, different levels of movement disorder in one case and hallucinations in one case. The results of MRI examination revealed gyri swelling, abnormal signal and demyelination of temporal lobe. The EEG showed focal or diffuse slow waves. All cases were confirmed to have the disease by detection of anti-NMDAR antibodies. Both the white blood cell count (3 cases and protein quantification (2 cases elevated. No tumor was detected in any of the patients. All patients were coued after receiving immunotherapy with methylprednisolone and human immunoglobulin.  Conclusions Anti-NMDAR encephalitis is a severe but treatable disorder. The syndrome is highly recognizable clinically and can be confirmed with the demonstration of anti-NMDAR antibodies. Timely diagnosis and treatment may yield a favorable prognosis. doi: 10.3969/j.issn.1672-6731.2014.07.005

  16. N-Methyl-d-Aspartate (NMDA Receptor Blockade Prevents Neuronal Death Induced by Zika Virus Infection

    Directory of Open Access Journals (Sweden)

    Vivian V. Costa

    2017-04-01

    Full Text Available Zika virus (ZIKV infection is a global health emergency that causes significant neurodegeneration. Neurodegenerative processes may be exacerbated by N-methyl-d-aspartate receptor (NMDAR-dependent neuronal excitoxicity. Here, we have exploited the hypothesis that ZIKV-induced neurodegeneration can be rescued by blocking NMDA overstimulation with memantine. Our results show that ZIKV actively replicates in primary neurons and that virus replication is directly associated with massive neuronal cell death. Interestingly, treatment with memantine or other NMDAR blockers, including dizocilpine (MK-801, agmatine sulfate, or ifenprodil, prevents neuronal death without interfering with the ability of ZIKV to replicate in these cells. Moreover, in vivo experiments demonstrate that therapeutic memantine treatment prevents the increase of intraocular pressure (IOP induced by infection and massively reduces neurodegeneration and microgliosis in the brain of infected mice. Our results indicate that the blockade of NMDARs by memantine provides potent neuroprotective effects against ZIKV-induced neuronal damage, suggesting it could be a viable treatment for patients at risk for ZIKV infection-induced neurodegeneration.

  17. Measurement of Creatine kinase and Aspartate aminotransferase in saliva of dogs: a pilot study.

    Science.gov (United States)

    Tvarijonaviciute, Asta; Barranco, Tomas; Rubio, Monica; Carrillo, Jose Maria; Martinez-Subiela, Silvia; Tecles, Fernando; Carrillo, Juana Dolores; Cerón, José J

    2017-06-09

    Muscle enzymes in saliva have been reported to be possible markers of heart and muscle damage in humans. The aim of this study was to assess if Creatine kinase (CK) and Aspartate aminotransferase (AST) activities could be measured in canine saliva, and to evaluate their possible changes in situations of muscle damage. The spectrophotometric assays for CK and AST measurement in saliva of dogs showed intra- and inter-assay imprecision lower than 1 and 16% and coefficients of correlation close to 1 in linearity under dilution tests. Healthy dogs showed activities in saliva of CK between 27 and 121 U/L and AST between 46 and 144 U/L, whereas in saliva of dogs with muscle damage CK ranged between 132 and 3862 U/L and AST between 154 and 4340 U/L. Positive moderate correlations were found between saliva and serum activities of the two enzymes (CK, r = 0.579; P = 0.001; AST, r = 0.674; P = 0.001). CK and AST activities can be measured in canine saliva with commercially available spectrophotometric assays. In addition these enzymes show higher values in saliva of dogs with muscle damage and their values are moderately correlated with those of serum.

  18. Clinical analysis on anti-N-methyl-D-aspartate receptor encephalitis cases: Chinese experience

    Science.gov (United States)

    Huang, Xiaoqin; Fan, Chunqiu; Wu, Jian; Ye, Jing; Zhan, Shuqin; Song, Haiqing; Liu, Aihua; Su, Yingying; Jia, Jianping

    2015-01-01

    As a kind of autoimmune encephalitis which was just identified, the clinical manifestations of the anti-N methyl-D aspartate (anti-NMDA) receptor encephalitis are complex, diverse and in severe condition. The immunotherapy has shown good effect on the treatment but in generally, the diagnosis and treatment are still in the experience accumulation stage. More clinical research in different population is necessary, for example, in the Chinese population. This study was completed in anti-NMDA receptor encephalitis patients who were diagnosed in Beijing Xuan Wu Hospital (China) during the time from 2011 to 2013. Total 33 patients were involved with the average age of 29.7 years old when the diseases were onset. With diverse clinical manifestations, most patients displayed positively by NMDAR antibody test and 63.6% of them were associated with elevated CSF-lgA. Patients also showed abnormal MRI and EEG. Only three patients had teratomas. With hormone therapy, gamma globulin treatment or plasma exchange, more than three quarters of patients fully recovered and the others had moderate symptoms. Based on our results, we suggest that NMDAR antibody test would be helpful to make a timely diagnosis and to administer immunotherapy. PMID:26770517

  19. Therapeutic effects of D-aspartate in a mouse model of multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Sanaz Afraei

    2017-07-01

    Full Text Available Experimental autoimmune encephalomyelitis (EAE is an animal model of multiple sclerosis. EAE is mainly mediated by adaptive and innate immune responses that leads to an inflammatory demyelization and axonal damage. The aim of the present research was to examine the therapeutic efficacy of D-aspartic acid (D-Asp on a mouse EAE model. EAE induction was performed in female C57BL/6 mice by myelin 40 oligodendrocyte glycoprotein (35-55 in a complete Freund's adjuvant emulsion, and D-Asp was used to test its efficiency in the reduction of EAE. During the course of study, clinical evaluation was assessed, and on Day 21, post-immunization blood samples were taken from the heart of mice for the evaluation of interleukin 6 and other chemical molecules. The mice were sacrificed, and their brain and cerebellum were removed for histological analysis. Our findings indicated that D-Asp had beneficial effects on EAE by attenuation in the severity and delay in the onset of the disease. Histological analysis showed that treatment with D-Asp can reduce inflammation. Moreover, in D-Asp-treated mice, the serum level of interleukin 6 was significantly lower than that in control animals, whereas the total antioxidant capacity was significantly higher. The data indicates that D-Asp possess neuroprotective property to prevent the onset of the multiple sclerosis.

  20. Linking Functional Domains of the Human Insulin Receptor with the Bacterial Aspartate Receptor

    Science.gov (United States)

    Ellis, Leland; Morgan, David O.; Koshland, Daniel E.; Clauser, Eric; Moe, Gregory R.; Bollag, Gideon; Roth, Richard A.; Rutter, William J.

    1986-11-01

    A hybrid receptor has been constructed that is composed of the extracellular domain of the human insulin receptor fused to the transmembrane and cytoplasmic domains of the bacterial aspartate chemoreceptor. This hybrid protein can be expressed in rodent (CHO) cells and displays several functional features comparable to wild-type insulin receptor. It is localized to the cell surface, binds insulin with high affinity, forms oligomers, and is recognized by conformation-specific monoclonal antibodies. Although most of the expressed protein accumulates as a 180-kDa proreceptor, some processed 135-kDa receptor can be detected on the cell surface by covalent cross-linking. Expression of the hybrid receptor inhibits the insulin-activated uptake of 2-deoxyglucose by CHO cells. Thus, this hybrid is partially functional and can be processed; however, it is incapable of native transmembrane signaling. The results indicate that the intact domains of different types of receptors can retain some of the native features in a hybrid molecule but specific requirements will need to be satisfied for transmembrane signaling.

  1. The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review

    Science.gov (United States)

    Roshanzamir, Farzad; Safavi, Seyyed Morteza

    2017-01-01

    Background: D-Aspartic acid (D-Asp) is in invertebrate and vertebrate neuroendocrine tissues, where it carries out important physiological functions. Recently, it has been reported that D-Asp is involved in the synthesis and release of testosterone and is assumed can be used as a testosterone booster for infertile men, and by athletes to increase muscle mass and strength. Objective: The aim of this review is to summarize available evidence related to the effects of D-Asp on serum testosterone levels. Materials and Methods: We conducted a systematic review of all type studies, which evaluated the effect of the D-Asp on blood testosterone including published papers until October 2015, using PubMed, ISI Web of Science, ProQuest and Scopus database. Results: With 396 retrieved records, 23 animal studies and 4 human studies were included. In vivo and in vitro animal studies revealed the effect of D-Asp depending on species, sex and organ-specific. Our results showed that exogenous D-Asp enhances testosterone levels in male animal’s studies, whereas studies in human yielded inconsistent results. The evidence for this association in man is still sparse, mostly because of limited number and poor quality studies. Conclusion: There is an urgent need for more and well-designed human clinical trials with larger sample sizes and longer duration to investigate putative effects of D-Asp on testosterone concentrations. PMID:28280794

  2. Finding a Leucine in a Haystack: Searching the Proteome for ambigous Leucine-Aspartic Acid motifs

    KAUST Repository

    Arold, Stefan T.

    2016-01-25

    Leucine-aspartic acid (LD) motifs are short helical protein-protein interaction motifs involved in cell motility, survival and communication. LD motif interactions are also implicated in cancer metastasis and are targeted by several viruses. LD motifs are notoriously difficult to detect because sequence pattern searches lead to an excessively high number of false positives. Hence, despite 20 years of research, only six LD motif–containing proteins are known in humans, three of which are close homologues of the paxillin family. To enable the proteome-wide discovery of LD motifs, we developed LD Motif Finder (LDMF), a web tool based on machine learning that combines sequence information with structural predictions to detect LD motifs with high accuracy. LDMF predicted 13 new LD motifs in humans. Using biophysical assays, we experimentally confirmed in vitro interactions for four novel LD motif proteins. Thus, LDMF allows proteome-wide discovery of LD motifs, despite a highly ambiguous sequence pattern. Functional implications will be discussed.

  3. Vaccination with recombinant aspartic hemoglobinase reduces parasite load and blood loss after hookworm infection in dogs.

    Directory of Open Access Journals (Sweden)

    Alex Loukas

    2005-10-01

    Full Text Available Hookworms infect 730 million people in developing countries where they are a leading cause of intestinal blood loss and iron-deficiency anemia. At the site of attachment to the host, adult hookworms ingest blood and lyse the erythrocytes to release hemoglobin. The parasites subsequently digest hemoglobin in their intestines using a cascade of proteolysis that begins with the Ancylostoma caninum aspartic protease 1, APR-1.We show that vaccination of dogs with recombinant Ac-APR-1 induced antibody and cellular responses and resulted in significantly reduced hookworm burdens (p = 0.056 and fecal egg counts (p = 0.018 in vaccinated dogs compared to control dogs after challenge with infective larvae of A. caninum. Most importantly, vaccinated dogs were protected against blood loss (p = 0.049 and most did not develop anemia, the major pathologic sequela of hookworm disease. IgG from vaccinated animals decreased the catalytic activity of the recombinant enzyme in vitro and the antibody bound in situ to the intestines of worms recovered from vaccinated dogs, implying that the vaccine interferes with the parasite's ability to digest blood.To the best of our knowledge, this is the first report of a recombinant vaccine from a hematophagous parasite that significantly reduces both parasite load and blood loss, and it supports the development of APR-1 as a human hookworm vaccine.

  4. Kinetic properties and thermal stabilities of mutant forms of mitochondrial aspartate aminotransferase.

    Science.gov (United States)

    Azzariti, A; Vacca, R A; Giannattasio, S; Merafina, R S; Marra, E; Doonan, S

    1998-07-28

    Kinetic properties and thermal stabilities of the precursor form of mitochondrial aspartate aminotransferase, the mature form lacking 9 amino acids from the N-terminus, and forms of the mature protein in which cysteine-166 had been mutated to serine or alanine were compared with those of the mature enzyme. The precursor and the cysteine mutants showed moderately impaired catalytic properties consistent with decreased ability to undergo transition from the open to the closed conformation which is an integral part of the mechanism of action of the enzyme. The deletion mutant had a kcat only 2% of that of the mature enzyme but also much reduced Km values for both substrates. In addition it showed enhanced reactivity of cysteine-166 with 5,5'-dithiobis(2-nitrobenzoate), which is characteristic of the closed form of the enzyme, with no enhancement of reactivity in the presence of substrates. This is taken to show that the deletion mutant adopts a conformation that is significantly different from that of the mature enzyme particularly in respect of the small domain. The deletion mutant was found to be more resistant to thermal inactivation over a range of temperatures than were the other forms of the enzyme consistent with its having a more tightly packed small domain.

  5. Effects of Zinc Magnesium Aspartate (ZMA Supplementation on Training Adaptations and Markers of Anabolism and Catabolism

    Directory of Open Access Journals (Sweden)

    Almada Anthony

    2004-12-01

    Full Text Available Abstract This study examined whether supplementing the diet with a commercial supplement containing zinc magnesium aspartate (ZMA during training affects zinc and magnesium status, anabolic and catabolic hormone profiles, and/or training adaptations. Forty-two resistance trained males (27 ± 9 yrs; 178 ± 8 cm, 85 ± 15 kg, 18.6 ± 6% body fat were matched according to fat free mass and randomly assigned to ingest in a double blind manner either a dextrose placebo (P or ZMA 30–60 minutes prior to going to sleep during 8-weeks of standardized resistance-training. Subjects completed testing sessions at 0, 4, and 8 weeks that included body composition assessment as determined by dual energy X-ray absorptiometry, 1-RM and muscular endurance tests on the bench and leg press, a Wingate anaerobic power test, and blood analysis to assess anabolic/catabolic status as well as markers of health. Data were analyzed using repeated measures ANOVA. Results indicated that ZMA supplementation non-significantly increased serum zinc levels by 11 – 17% (p = 0.12. However, no significant differences were observed between groups in anabolic or catabolic hormone status, body composition, 1-RM bench press and leg press, upper or lower body muscular endurance, or cycling anaerobic capacity. Results indicate that ZMA supplementation during training does not appear to enhance training adaptations in resistance trained populations.

  6. Lactate oxidation at the mitochondria: a lactate-malate-aspartate shuttle at work

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    Daniel A Kane

    2014-11-01

    Full Text Available Lactate, the conjugate base of lactic acid occurring in aqueous biological fluids, has been derided as a dead-end waste product of anaerobic metabolism. Catalyzed by the near-equilibrium enzyme lactate dehydrogenase (LDH, the reduction of pyruvate to lactate is thought to serve to regenerate the NAD+ necessary for continued glycolytic flux. Reaction kinetics for LDH imply that lactate oxidation is rarely favored in the tissues of its own production. However, a substantial body of research directly contradicts any notion that LDH invariably operates unidirectionally in vivo. In the current Perspective, a model is forwarded in which the continuous formation and oxidation of lactate serves as a mitochondrial electron shuttle, whereby lactate generated in the cytosol of the cell is oxidized at the mitochondria of the same cell. From this perspective, an intracellular lactate shuttle operates much like the malate-aspartate shuttle; it is also proposed that the two shuttles are necessarily interconnected. Among the requisite features of such a model, significant compartmentalization of LDH, much like the creatine kinase of the PCr shuttle, would facilitate net cellular lactate oxidation under a variety of conditions.

  7. Influence of aspartic acid and lysine on the uptake of gold nanoparticles in rice.

    Science.gov (United States)

    Ye, Xinxin; Li, Hongying; Wang, Qingyun; Chai, Rushan; Ma, Chao; Gao, Hongjian; Mao, Jingdong

    2017-11-01

    The interactions between plants and nanomaterials (NMs) can shed light on the environmental consequences of nanotechnology. We used the major crop plant rice (Oryza sativa L.) to investigate the uptake of gold nanoparticles (GNPs) coated with either negatively or positively charged ligands, over a 5-day period, in the absence or presence of one of two amino acids, aspartic acid (Asp) or lysine (Lys), acting as components of rice root exudates. The presence of Asp or Lys influenced the uptake and distribution of GNPs in rice, which depended on the electrical interaction between the coated GNPs and each amino acid. When the electrical charge of the amino acid was the same as that of the surface ligand coated onto the GNPs, the GNPs could disperse well in nutrient solution, resulting in increased uptake of GNPs into rice tissue. The opposite was true where the charge on the surface ligand was different from that on the amino acid, resulting in agglomeration and reduced Au uptake into rice tissue. The behavior of GNPs in the hydroponic nutrient solution was monitored in terms of agglomeration, particle size distribution, and surface charge in the presence and absence of Asp or Lys, which depended strongly on the electrostatic interaction. Results from this study indicated that the species of root exudates must be taken into account in assessing the bioavailability of nanomaterials to plants. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Site-directed mutagenesis, kinetic and inhibition studies of aspartate ammonia lyase from Bacillus sp. YM55-1.

    Science.gov (United States)

    Puthan Veetil, Vinod; Raj, Hans; Quax, Wim J; Janssen, Dick B; Poelarends, Gerrit J

    2009-06-01

    Aspartate ammonia lyases (also referred to as aspartases) catalyze the reversible deamination of L-aspartate to yield fumarate and ammonia. In the proposed mechanism for these enzymes, an active site base abstracts a proton from C3 of L-aspartate to form an enzyme-stabilized enediolate intermediate. Ketonization of this intermediate eliminates ammonia and yields the product, fumarate. Although two crystal structures of aspartases have been determined, details of the catalytic mechanism have not yet been elucidated. In the present study, eight active site residues (Thr101, Ser140, Thr141, Asn142, Thr187, His188, Lys324 and Asn326) were mutated in the structurally characterized aspartase (AspB) from Bacillus sp. YM55-1. On the basis of a model of the complex in which L-aspartate was docked manually into the active site of AspB, the residues responsible for binding the amino group of L-aspartate were predicted to be Thr101, Asn142 and His188. This postulate is supported by the mutagenesis studies: mutations at these positions resulted in mutant enzymes with reduced activity and significant increases in the K(m) for L-aspartate. Studies of the pH dependence of the kinetic parameters of AspB revealed that a basic group with a pK(a) of approximately 7 and an acidic group with a pK(a) of approximately 10 are essential for catalysis. His188 does not play the typical role of active site base or acid because the H188A mutant retained significant activity and displayed an unchanged pH-rate profile compared to that of wild-type AspB. Mutation of Ser140 and Thr141 and kinetic analysis of the mutant enzymes revealed that these residues are most likely involved in substrate binding and in stabilizing the enediolate intermediate. Mutagenesis studies corroborate the essential role of Lys324 because all mutations at this position resulted in mutant enzymes that were completely inactive. The substrate-binding model and kinetic analysis of mutant enzymes suggest that Thr187 and Asn326

  9. Release of free amino acids upon oxidation of peptides and proteins by hydroxyl radicals.

    Science.gov (United States)

    Liu, Fobang; Lai, Senchao; Tong, Haijie; Lakey, Pascale S J; Shiraiwa, Manabu; Weller, Michael G; Pöschl, Ulrich; Kampf, Christopher J

    2017-03-01

    Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide. The molar yields of free glycine, aspartic acid, asparagine, and alanine per peptide or protein varied between 4 and 55%. For protein oxidation reactions, the molar yields of Gly (∼32-55% for BSA, ∼10-21% for OVA) were substantially higher than those for the other identified amino acids (∼5-12% for BSA, ∼4-6% for OVA). Upon oxidation of tripeptides with Gly in C-terminal, mid-chain, or N-terminal positions, Gly was preferentially released when it was located at the C-terminal site. Overall, we observe evidence for a site-selective formation of free amino acids in the OH radical-induced oxidation of peptides and proteins, which may be due to a reaction pathway involving nitrogen-centered radicals.

  10. RGD-peptide modified alginate by a chemoenzymatic strategy for tissue engineering applications.

    Science.gov (United States)

    Sandvig, Ioanna; Karstensen, Kristin; Rokstad, Anne Mari; Aachmann, Finn Lillelund; Formo, Kjetil; Sandvig, Axel; Skjåk-Bræk, Gudmund; Strand, Berit Løkensgard

    2015-03-01

    One of the main challenges in tissue engineering and regenerative medicine is the ability to maintain optimal cell function and survival post-transplantation. Biomaterials such as alginates are commonly used for immunoisolation, while they may also provide structural support to the cell transplants by mimicking the extracellular matrix. In this study, arginine-glycine-aspartate (RGD)-peptide-coupled alginates of tailored composition were produced by adopting a unique chemoenzymatic strategy for substituting the nongelling mannuronic acid on the alginate. Alginates with and without RGD were produced with high and low content of G. Using carbodiimide chemistry 0.1-0.2% of the sugar units were substituted by peptide. Furthermore, the characterization by (1)H-nuclear magnetic resonance (NMR) revealed by-products from the coupling reaction that partly could be removed by coal filtration. Olfactory ensheathing cells (OECs) and myoblasts were grown in two-dimensional (2D) and 3D cultures of RGD-peptide modified or unmodified alginates obtained by the chemoenzymatically strategy and compared to native alginate. Both OECs and myoblasts adhered to the RGD-peptide modified alginates in 2D cultures, forming bipolar protrusions. OEC encapsulation resulted in cell survival for up to 9 days, thus demonstrating the potential for short-term 3D culture. Myoblasts showed long-term survival in 3D cultures, that is, up to 41 days post encapsulation. The RGD modifications did not result in marked changes in cell viability in 3D cultures. We demonstrate herein a unique technique for tailoring peptide substituted alginates with a precise and flexible composition, conserving the gel forming properties relevant for the use of alginate in tissue engineering. © 2014 Wiley Periodicals, Inc.

  11. Antimicrobial efficacy of granulysin-derived synthetic peptides in acne vulgaris.

    Science.gov (United States)

    Lim, Hee-Sun; Chun, Seung-Min; Soung, Min-Gyu; Kim, Jenny; Kim, Seong-Jin

    2015-07-01

    Antimicrobial peptides are considered as a potential alternative to antibiotic treatment in acne vulgaris because the development of a resistant strain of Propionibacterium acnes is problematic. Granulysin can be regarded as an ideal substance with which to treat acne because it has antimicrobial and anti-inflammatory effects. This study was performed to explore the effectiveness of granulysin-derived peptides (GDPs) in killing P. acnes in vitro under a standard microbiologic assay and to evaluate their potential use in a topical agent for the treatment of acne vulgaris. Twenty different peptides based on the known sequence of a GDP were synthesized and tested in vitro for antimicrobial activity. Thirty patients with facial acne vulgaris were instructed to apply a topical formulation containing synthetic GDP to acne lesions twice per day for 12 weeks. A newly synthesized peptide in which aspartic acid was substituted with arginine, and methionine was substituted with cysteine, showed the highest antimicrobial activity against P. acnes. Moreover, it was effective against both Gram-positive and Gram-negative bacteria in vitro. After treatment with the topical formulation containing 50 ppm of synthetic peptide for 12 weeks, a significant reduction in the number of pustules was observed, regardless of the increase in the number of comedones. In addition, a significant reduction in the clinical grade of acne based on the Korean Acne Grading System (KAGS) was evident. Synthesized GDP shows strong antimicrobial activity against P. acnes in vitro. The clinical improvement observed suggests a topical formulation containing the GDP has therapeutic potential for the improvement of inflammatory-type acne vulgaris by its antimicrobial activity. © 2015 The International Society of Dermatology.

  12. Identification of peptide-cross-linked trisdisaccharide peptide trimers in murein of Escherichia coli.

    OpenAIRE

    Gmeiner, J

    1980-01-01

    Purified murein from Escherichia coli K-12 was degraded into disaccharide peptide fragments by endo-N-acetylmuramidase from Chalaropsis. About 5% of the total murein fragments were recovered as peptide-cross-linked trisdisaccharide peptide trimers.

  13. Versatile Peptide C-Terminal Functionalization via a Computationally Engineered Peptide Amidase

    NARCIS (Netherlands)

    Wu, Bian; Wijma, Hein J.; Song, Lu; Rozeboom, Henriette J.; Poloni, Claudia; Tian, Yue; Arif, Muhammad I.; Nuijens, Timo; Quaedflieg, Peter J. L. M.; Szymanski, Wiktor; Feringa, Ben L.; Janssen, Dick B.

    The properties of synthetic peptides, including potency, stability, and bioavailability, are strongly influenced by modification of the peptide chain termini. Unfortunately, generally applicable methods for selective and mild C-terminal peptide functionalization are lacking. In this work, we

  14. A rapid and clean synthetic approach to cyclic peptides via micro-flow peptide chain elongation and photochemical cyclization: synthesis of a cyclic RGD peptide.

    Science.gov (United States)

    Mifune, Yuto; Nakamura, Hiroyuki; Fuse, Shinichiro

    2016-11-29

    A cyclic RGD peptide was efficiently synthesized based on micro-flow, triphosgene-mediated peptide chain elongation and micro-flow photochemical macrolactamization. Our approach enabled a rapid (amidation for peptide chain elongation peptide.

  15. Novel Approach to Prepare {sup 99m}Tc-Based Multivalent RGD Peptides

    Energy Technology Data Exchange (ETDEWEB)

    Shuang Liu

    2012-10-24

    This project presents a novel approach to prepare the {sup 99m}Tc-bridged multivalent RGD (arginine-glycine-aspartate) peptides. This project will focus on fundamentals of {sup 99m}Tc radiochemistry. The main objective of this project is to demonstrate the proof-of-principle for the proposed radiotracers. Once a kit formulation is developed for preparation of the {sup 99m}Tc-bridged multivalent RGD peptides, various tumor-bearing animal models will be used to evaluate their potential for SPECT (single photon-emission computed tomography) imaging of cancer. We have demonstrated that (1) multimerization of cyclic RGD peptides enhances the integrin {alpha}{sub v}{beta}{sub 3} bonding affinity and radiotracer tumor uptake; (2) addition of G{sub 3} or PEG{sub 4} linkers makes it possible for two RGD motifs in 3P-RGD{sub 2} and 3G-RGD{sub 2} to achieve simultaneous integrin {alpha}{sub v}{beta}{sub 3} binding; and (3) multimers are actually bivalent (not multivalent), the presence of extra RGD motifs can enhance the tumor retention time of the radiotracer.

  16. Cyanobacterial peptides as a prototype for the design of cathepsin D inhibitors.

    Science.gov (United States)

    Xu, Hao; Bao, Keting; Tang, Shuai; Ai, Jing; Hu, Haiyan; Zhang, Wei

    2017-09-01

    Cathepsin D (Cath D) is overexpressed and secreted in a number of solid tumors and involved in the progress of tumor invasion, proliferation, metastasis, and apoptosis. Inhibition of Cath D is regarded as an attractive pathway for the development of novel anticancer drugs. Our previous studies revealed that tasiamide B, a cyanobacterial peptide that contained a statine-like unit, exhibited good inhibition against Cath D and other aspartic proteases. Using this natural product as prototype, we designed and synthesized three new analogs, which bear isophthalic acid fragment at the N-terminus and isobutyl amine (1), cyclopropyl amine (2), or 3-methoxybenzyl amine (3) moiety at the C-terminus. Enzymatic assays revealed that all these three compounds showed moderate-to-good inhibition against Cath D, with IC50 s of 15, 884, and 353 nM, respectively. Notably, compound 1 showed extreme selectivity for Cath D with 576-fold over Cath E and 554-fold over BACE1, which could be a valuable template for the design of highly potent and selective Cath D inhibitors. Additionally, compound 1 showed moderated activity against HeLa cell lines with IC50 of 41.8 μM. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  17. Preservation of peptide moieties in three Spanish sulfur-rich Tertiary kerogens

    Energy Technology Data Exchange (ETDEWEB)

    Rio, J.C. del [Consejo Superior de Investigaciones Cientificas, Seville (Spain). Inst. de Recursos Naturales y Agrobiologia; Olivella, M.A.; Heras, F.X.D. de las [Escola Universitaria Politecnica de Manresa, Catalonia (Spain); Knicker, H. [Technische Universitaet Muenchen (Germany). Lehrstuhl fuer Bodenkunde

    2004-09-01

    Thermochemolysis with tetramethylammonium hydroxide (TMAH) and solid-state {sup 15}N NMR were utilized for the characterization of refractory organic nitrogen in Tertiary Spanish kerogens. The samples included sulfur-rich oil shales from the Ribesalbes (Serravallian), Libros (Tortonian) and Cerdanya (Tortonian) basins. Analysis using solid state {sup 15}N NMR showed that part of the refractory nitrogen in the kerogens corresponds to amide groups. Moreover, the release of amino acid derivatives after pyrolysis in the presence of TMAH indicated that this amide-N arose from peptide moieties. The amino acids released from the kerogens were dominated by high amounts of glycine and alanine. Minor amounts of aspartic acid, serine, {alpha}-aminobutyric acid and other unidentified amino acids were also detected. Because proteinaceous structures, including small peptides, are generally considered as being highly sensitive to diagenetic degradation, encapsulation of labile peptide material into aliphatic structures in S-rich kerogens (probably via lipid sulfurization) has been proposed to explain the survival of these moieties. Substantial amounts of fatty acids (as methyl esters) were also released from all the kerogens after pyrolysis/TMAH, indicating their highly aliphatic character. The production of both fatty acids and amino acids from the kerogens supports the encapsulation process. (author)

  18. Cyclic RGD Peptides Incorporating Cycloalkanes: Synthesis and Evaluation as PET Radiotracers for Tumor Imaging.

    Science.gov (United States)

    Park, Ji-Ae; Lee, Yong Jin; Lee, Ji Woong; Lee, Kyo Chul; An, Gwang Il; Kim, Kyeong Min; Kim, Byung Il; Kim, Tae-Jeong; Kim, Jung Young

    2014-09-11

    Two new bicyclic arginine-glycine-aspartic acid (RGD) peptides, c(RGD-ACP-K) (1a) and c(RGD-ACH-K) (1b), incorporating the aminocyclopentane (ACP) and aminocyclohexane (ACH) carboxylic acids, respectively, were synthesized by grafting the aminocycloalkane carboxylic acids onto the tetra-peptide RGDK sequence. These peptides and their conjugates with DO3A (1,4,7,10-tetraazacyclododecane-1,4,7-trisacetic acid) (2a-b) exhibit high affinity toward U87MG glioblastoma cells. Their affinity is greater than that exhibited by c(RGDyK). Labeling these conjugates with radiometal (64)Cu resulted in high radiochemical yields (>97%) of the corresponding complexes, abbreviated as c(RGD-ACP-K)-DOTA-(64)Cu (3a) and c(RGD-ACH-K)-DOTA-(64)Cu (3b). Both 3a and 3b are stable for 24 h in human and mouse serums and show high tumor uptake, as observed by positron emission tomography (PET). Blocking experiments with 3a and 3b by preinjection of c(RGDyK) confirmed their target specificity and demonstrated their promise as PET radiotracers for imaging ανβ3-positive tumors.

  19. Application of bare gold nanoparticles in open-tubular CEC separations of polyaromatic hydrocarbons and peptides.

    Science.gov (United States)

    Řezanka, Pavel; Ehala, Sille; Koktan, Jakub; Sýkora, David; Žvátora, Pavel; Vosmanská, Magda; Král, Vladimír; Mikšík, Ivan; Čeřovský, Václav; Kašička, Václav

    2012-01-01

    In this study, bare gold nanoparticles (GNPs) immobilized in the sol-gel-pretreated fused-silica (FS) capillary as a stationary phase for open-tubular capillary electrochromatography (OT-CEC) are for the first time shown to be able to separate both hydrophobic polyaromatic hydrocarbons (PAHs) as well as hydrophilic cationic antimicrobial peptides. Model mixture of four PAHs, naphthalene, fluorene, phenanthrene, and anthracene, was resolved by OT-CEC in the GNP-modified FS capillaries using the hydro-organic background electrolyte (BGE) composed of 20 mmol/L sodium phosphate buffer, pH 7, modified with ACN at 8:2 v/v ratio. On the other hand, three synthetic analogues of an antimicrobial peptide mastoparan PDD-B, basic tetradecapeptides INWKKLGKKILGAL-NH(2), INSLKLGKKILGAL-NH(2) and NWLRLGRRILGAL-NH(2), were separated in aqueous acidic BGEs, pH 2.1-3.1, composed of weak acids (formic and acetic) or amphoteric amino or imino acids (aspartic or iminodiacetic), utilizing the advantage of a slow reversed (anodic) EOF and slightly positive charge of the GNP-modified FS capillary suppressing the adsorption of cationic peptides on the inner capillary wall and improving their resolution. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Peptides and Food Intake

    Directory of Open Access Journals (Sweden)

    Carmen Sobrino Crespo

    2014-04-01

    Full Text Available Nutrients created by the digestion of food are proposed to active G protein coupled receptors on the luminal side of enteroendocrine cells e.g. the L-cell. This stimulates the release of gut hormones. Hormones released from the gut and adipose tissue play an important rol in the regulation of food intake and energy expenditure (1.Many circulating signals, including gut hormones, can influence the activity of the arcuate nucleus (ARC neurons directly, after passing across the median eminence. The ARC is adjacent to the median eminence, a circumventricular organ with fenestrated capillaries and hence an incomplete blood-brain barrier (2. The ARC of the hypothalamus is believed to play a crucial role in the regulation of food intake and energy homeostasis. The ARC contains two populations of neurons with opposing effect on food intake (3. Medially located orexigenic neurons (i.e those stimulating appetite express neuropeptide Y (NPY and agouti-related protein (AgRP (4-5. Anorexigenic neurons (i.e. those inhibiting appetite in the lateral ARC express alpha-melanocyte stimulating hormone (α-MSH derived from pro-opiomelanocortin (POMC and cocaine and amphetamine-regulated transcript (CART (6. The balance between activities of these neuronal circuits is critical to body weight regulation.In contrast, other peripheral signals influence the hypothalamus indirectly via afferent neuronal pathway and brainstem circuits. In this context gastrointestinal’s vagal afferents are activated by mechanoreceptors and chemoreceptors, and converge in the nucleus of the tractus solitaries (NTS of the brainstem. Neuronal projections from the NTS, in turn, carry signals to the hypotalamus (1, 7. Gut hormones also alter the activity of the ascending vagal pathway from the gut to the brainstem. In the cases of ghrelin and Peptide tyrosine tyrosine (PYY, there are evidences for both to have a direct action on the arcuate nucleus and an action via the vagus nerve a

  1. Automated solid-phase peptide synthesis to obtain therapeutic peptides

    Directory of Open Access Journals (Sweden)

    Veronika Mäde

    2014-05-01

    Full Text Available The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies.

  2. Recent advances in solid-phase peptide synthesis and preparation of antibodies to synthetic peptides.

    Science.gov (United States)

    Plaue, S; Muller, S; Briand, J P; Van Regenmortel, M H

    1990-07-01

    Peptides prepared by the solid-phase peptide synthesis (SPPS) approach are used increasingly in biological research, for instance to elicit anti-peptide antibodies that will recognize the intact, cognate protein. Recent advances in SPPS are reviewed, including the use of new coupling reagents, new methods for evaluating peptide purity and new techniques of automated and multiple peptide synthesis. Methods for enhancing peptide immunogenicity are discussed such as the use of adjuvants and liposomes, and of synthetic branched polypeptides as carriers.

  3. Solid-State Synthesis, Characterization, and Biological Activity of the Bioinorganic Complex of Aspartic Acid and Arsenic Triiodide

    Directory of Open Access Journals (Sweden)

    Guo-Qing Zhong

    2013-01-01

    Full Text Available The bioinorganic complex of aspartic acid and arsenic triiodide was synthesized by a solid-state reaction at room temperature. The formula of the complex is AsI3[HOOCCH2CH(NH2COOH]2.5. The crystal structure of the complex belongs to monoclinic system with lattice parameters: a=1.0019 nm, b=1.5118 nm, c=2.1971 nm, and β=100.28°. The infrared spectra can demonstrate the complex formation between the arsenic ion and aspartic acid, and the complex may be a dimer with bridge structure. The result of primary biological test indicates that the complex possesses better biological activity for the HL-60 cells of the leukemia than arsenic triiodide.

  4. Aspartic acid racemization rate in narwhal (Monodon monoceros) eye lens nuclei estimated by counting of growth layers in tusks

    DEFF Research Database (Denmark)

    Garde, Eva; Heide-Jørgensen, Mads Peter; Ditlevsen, Susanne

    2012-01-01

    Ages of marine mammals have traditionally been estimated by counting dentinal growth layers in teeth. However, this method is difficult to use on narwhals (Monodon monoceros) because of their special tooth structures. Alternative methods are therefore needed. The aspartic acid racemization (AAR......) technique has been used in age estimation studies of cetaceans, including narwhals. The purpose of this study was to estimate a species-specific racemization rate for narwhals by regressing aspartic acid D/L ratios in eye lens nuclei against growth layer groups in tusks (n=9). Two racemization rates were...... rate and (D/L)0 value be used in future AAR age estimation studies of narwhals, but also recommend the collection of tusks and eyes of narwhals for further improving the (D/L)0 and 2kAsp estimates obtained in this study....

  5. Perspectives and Peptides of the Next Generation

    Science.gov (United States)

    Brogden, Kim A.

    Shortly after their discovery, antimicrobial peptides from prokaryotes and eukaryotes were recognized as the next potential generation of pharmaceuticals to treat antibiotic-resistant bacterial infections and septic shock, to preserve food, or to sanitize surfaces. Initial research focused on identifying the spectrum of antimicrobial agents, determining the range of antimicrobial activities against bacterial, fungal, and viral pathogens, and assessing the antimicrobial activity of synthetic peptides versus their natural counterparts. Subsequent research then focused on the mechanisms of antimicrobial peptide activity in model membrane systems not only to identify the mechanisms of antimicrobial peptide activity in microorganisms but also to discern differences in cytotoxicity for prokaryotic and eukaryotic cells. Recent, contemporary work now focuses on current and future efforts to construct hybrid peptides, peptide congeners, stabilized peptides, peptide conjugates, and immobilized peptides for unique and specific applications to control the growth of microorganisms in vitro and in vivo.

  6. [Peptides: a new class of anticancer drugs].

    Science.gov (United States)

    Smolarczyk, Ryszard; Cichoń, Tomasz; Szala, Stanisław

    2009-07-22

    Peptides are a novel class of anticancer agents embracing two distinct categories: natural antibacterial peptides, which are preferentially bound by cancer cells, and chemically synthesized peptides, which bind specifically to precise molecular targets located on the surface of tumor cells. Antibacterial peptides bind to both cell and mitochondrial membranes. Some of these peptides attach to the cell membrane, resulting in its disorganization. Other antibacterial peptides penetrate cancer cells without causing cell membrane damage, but they disrupt mitochondrial membranes. Thanks to phage and aptamer libraries, it has become possible to obtain synthetic peptides blocking or activating some target proteins found in cancer cells as well as in cells forming the tumor environment. These synthetic peptides can feature anti-angiogenic properties, block enzymes indispensable for sustained tumor growth, and reduce tumor ability to metastasize. In this review the properties of peptides belonging to both categories are discussed and attempts of their application for therapeutic purposes are outlined.

  7. Peptides: A new class of anticancer drugs

    Directory of Open Access Journals (Sweden)

    Ryszard Smolarczyk

    2009-07-01

    Full Text Available Peptides are a novel class of anticancer agents embracing two distinct categories: natural antibacterial peptides, which are preferentially bound by cancer cells, and chemically synthesized peptides, which bind specifically to precise molecular targets located on the surface of tumor cells. Antibacterial peptides bind to both cell and mitochondrial membranes. Some of these peptides attach to the cell membrane, resulting in its disorganization. Other antibacterial peptides penetrate cancer cells without causing cell membrane damage, but they disrupt mitochondrial membranes. Thanks to phage and aptamer libraries, it has become possible to obtain synthetic peptides blocking or activating some target proteins found in cancer cells as well as in cells forming the tumor environment. These synthetic peptides can feature anti-angiogenic properties, block enzymes indispensable for sustained tumor growth, and reduce tumor ability to metastasize. In this review the properties of peptides belonging to both categories are discussed and attempts of their application for therapeutic purposes are outlined.

  8. Peptide Selection for Targeted Protein Quantitation.

    Science.gov (United States)

    Chiva, Cristina; Sabidó, Eduard

    2017-03-03

    Targeted proteomics methods in their different flavors rely on the use of a few peptides as proxies for protein quantitation, which need to be specified either prior to or after data acquisition. However, in contrast with discovery methods that use all identified peptides for a given protein to estimate its abundance, targeted proteomics methods are limited in the number of peptides that are used for protein quantitation. Because only a few peptides per protein are acquired or extracted in targeted experiments, the selection of peptides that are used for targeted protein quantitation becomes crucial. Several rules have been proposed to guide peptide selection for targeted proteomics studies, which have generally been based on the amino acidic composition of the peptide sequences. However, the compliance of these rules does not imply that not-conformed peptides are not reproducibly generated nor do they guarantee that the selected peptides correctly represent the behavior of the protein abundance under different conditions.

  9. Brain-derived neurotrophic factor modulates hippocampal synaptic transmission by increasing N-methyl-d-aspartic acid receptor activity

    OpenAIRE

    Levine, Eric S; Crozier, Robert A.; Black, Ira B.; Plummer, Mark R.

    1998-01-01

    Neurotrophins (NTs) have recently been found to regulate synaptic transmission in the hippocampus. Whole-cell and single-channel recordings from cultured hippocampal neurons revealed a mechanism responsible for enhanced synaptic strength. Specifically, brain-derived neurotrophic factor augmented glutamate-evoked, but not acetylcholine-evoked, currents 3-fold and increased N-methyl-d-aspartic acid (NMDA) receptor open probability. Activation of trkB NT receptors was critical, as glutamate curr...

  10. Brain-derived neurotrophic factor rapidly enhances phosphorylation of the postsynaptic N-methyl-d-aspartate receptor subunit 1

    OpenAIRE

    Suen, Piin-Chau; Wu, Kuo; Levine, Eric S; Mount, Howard T. J.; Xu, Jia-Ling; LIN, SIANG-YO; Black, Ira B.

    1997-01-01

    Although neurotrophins have traditionally been regarded as neuronal survival factors, recent work has suggested a role for these factors in synaptic plasticity. In particular, brain-derived neurotrophic factor (BDNF) rapidly enhances synaptic transmission in hippocampal neurons through trkB receptor stimulation and postsynaptic phosphorylation mechanisms. Activation of trkB also modulates hippocampal long-term potentiation, in which postsynaptic N-methyl-d-aspartate glutamate receptors play a...

  11. An Essential Role of the Mitochondrial Electron Transport Chain in Cell Proliferation Is to Enable Aspartate Synthesis

    OpenAIRE

    Freinkman, Elizaveta; Wang, Tim; Chen, Walter W.; Abu-Remaileh, Monther; Sabatini, David; Birsoy, Kivanc

    2015-01-01

    The mitochondrial electron transport chain (ETC) enables many metabolic processes, but why its inhibition suppresses cell proliferation is unclear. It is also not well understood why pyruvate supplementation allows cells lacking ETC function to proliferate. We used a CRISPR-based genetic screen to identify genes whose loss sensitizes human cells to phenformin, a complex I inhibitor. The screen yielded GOT1, the cytosolic aspartate aminotransferase, loss of which kills cells upon ETC inhibitio...

  12. Hemoglobin degradation in the human malaria pathogen Plasmodium falciparum: a catabolic pathway initiated by a specific aspartic protease

    OpenAIRE

    1991-01-01

    Hemoglobin is an important nutrient source for intraerythrocytic malaria organisms. Its catabolism occurs in an acidic digestive vacuole. Our previous studies suggested that an aspartic protease plays a key role in the degradative process. We have now isolated this enzyme and defined its role in the hemoglobinolytic pathway. Laser desorption mass spectrometry was used to analyze the proteolytic action of the purified protease. The enzyme has a remarkably stringent specificity towards native h...

  13. Crystal structure of Clostridium acetobutylicum aspartate kinase (CaAk: An important allosteric enzyme for amino acids production

    Directory of Open Access Journals (Sweden)

    Babu A. Manjasetty

    2014-09-01

    Full Text Available Aspartate kinase (AK is an enzyme which is tightly regulated through feedback control and responsible for the synthesis of 4-phospho-l-aspartate from l-aspartate. This intermediate step is at an important branch point where one path leads to the synthesis of lysine and the other to threonine, methionine and isoleucine. Concerted feedback inhibition of AK is mediated by threonine and lysine and varies between the species. The crystal structure of biotechnologically important Clostridium acetobutylicum aspartate kinase (CaAK; E.C. 2.7.2.4; Mw = 48,030 Da; 437aa; SwissProt: Q97MC0 has been determined to 3 Å resolution. CaAK acquires a protein fold similar to the other known structures of AKs despite the low sequence identity (<30%. It is composed of two domains: an N-terminal catalytic domain (kinase domain and a C-terminal regulatory domain further comprised of two small domains belonging to the ACT domain family. Pairwise comparison of 12 molecules in the asymmetric unit helped to identify the bending regions which are in the vicinity of ATP binding site involved in domain movements between the catalytic and regulatory domains. All 12 CaAK molecules adopt fully open T-state conformation leading to the formation of three tetramers unique among other similar AK structures. On the basis of comparative structural analysis, we discuss tetramer formation based on the large conformational changes in the catalytic domain associated with the lysine binding at the regulatory domains. The structure described herein is homologous to a target in wide-spread pathogenic (toxin producing bacteria such as Clostridium tetani (64% sequence identity suggesting the potential of the structure solved here to be applied for modeling drug interactions. CaAK structure may serve as a guide to better understand and engineer lysine biosynthesis for the biotechnology industry.

  14. Peptide pool immunization and CD8+ T cell reactivity

    DEFF Research Database (Denmark)

    Rasmussen, Susanne B; Harndahl, Mikkel N; Buus, Anette Stryhn

    2013-01-01

    peptides induced normal peptide immunity i.e. the specific T cell reactivity in the Elispot culture was strictly dependent on exposure to the immunizing peptide ex vivo. However, immunization with two of the peptides, a VSV- and a Mycobacterium-derived peptide, resulted in IFNγ spot formation without...... peptide in the Elispot culture. Immunization with a mixture of the VSV-peptide and a "normal" peptide also resulted in IFNγ spot formation without addition of peptide to the assay culture. Peptide-tetramer staining of CD8(+) T cells from mice immunized with a mixture of VSV-peptide and "normal" peptide...

  15. An injectable and biodegradable hydrogel based on poly(α,β-aspartic acid) derivatives for localized drug delivery.

    Science.gov (United States)

    Lu, Caicai; Wang, Xiaojuan; Wu, Guolin; Wang, Jingjing; Wang, Yinong; Gao, Hui; Ma, Jianbiao

    2014-03-01

    An injectable hydrogel via hydrazone cross-linking was prepared under mild conditions without addition of cross-linker or catalyst. Hydrazine and aldehyde modified poly(aspartic acid)s were used as two gel precursors. Both of them are water-soluble and biodegradable polymers with a protein-like structure, and obtained by aminolysis reaction of polysuccinimide. The latter can be prepared by thermal polycondensation of aspartic acid. Hydrogels were prepared in PBS solution and characterized by different methods including gel content and swelling, Fourier transformed-infrared spectroscopy, and in vitro degradation experiment. A scanning electron microscope viewed the interior morphology of the obtained hydrogels, which showed porous three-dimensional structures. Different porous sizes were present, which could be well controlled by the degree of aldehyde substitution in precursor poly(aspartic acid) derivatives. The doxorubicin-loaded hydrogels were prepared and showed a pH-sensitive release profile. The release rate can be accelerated by decreasing the environmental pH from a physiological to a weak acidic condition. Moreover, the cell adhesion and growth behaviors on the hydrogel were studied and the polymeric hydrogel showed good biocompatibility. Copyright © 2013 Wiley Periodicals, Inc.

  16. Expression, purification, crystallization and preliminary X-ray diffraction analysis of the aspartate transcarbamoylase domain of human CAD.

    Science.gov (United States)

    Ruiz-Ramos, Alba; Lallous, Nada; Grande-García, Araceli; Ramón-Maiques, Santiago

    2013-12-01

    Aspartate transcarbamoylase (ATCase) catalyzes the synthesis of N-carbamoyl-L-aspartate from carbamoyl phosphate and aspartate in the second step of the de novo biosynthesis of pyrimidines. In prokaryotes, the first three activities of the pathway, namely carbamoyl phosphate synthetase (CPSase), ATCase and dihydroorotase (DHOase), are encoded as distinct proteins that function independently or in noncovalent association. In animals, CPSase, ATCase and DHOase are part of a 243 kDa multifunctional polypeptide named CAD. Up-regulation of CAD is essential for normal and tumour cell proliferation. Although the structures of numerous prokaryotic ATCases have been determined, there is no structural information about any eukaryotic ATCase. In fact, the only detailed structural information about CAD is that it self-assembles into hexamers and trimers through interactions of the ATCase domains. Here, the expression, purification and crystallization of the ATCase domain of human CAD is reported. The recombinant protein, which was expressed in bacteria and purified with good yield, formed homotrimers in solution. Crystallization experiments both in the absence and in the presence of the inhibitor PALA yielded small crystals that diffracted X-rays to 2.1 Å resolution using synchrotron radiation. The crystals appeared to belong to the hexagonal space group P6(3)22, and Matthews coefficient calculation indicated the presence of one ATCase subunit per asymmetric unit, with a solvent content of 48%. However, analysis of the intensity statistics suggests a special case of the P21 lattice with pseudo-symmetry and possibly twinning.

  17. SIRT3-dependent GOT2 acetylation status affects the malate–aspartate NADH shuttle activity and pancreatic tumor growth

    Science.gov (United States)

    Yang, Hui; Zhou, Lisha; Shi, Qian; Zhao, Yuzheng; Lin, Huaipeng; Zhang, Mengli; Zhao, Shimin; Yang, Yi; Ling, Zhi-Qiang; Guan, Kun-Liang; Xiong, Yue; Ye, Dan

    2015-01-01

    The malate–aspartate shuttle is indispensable for the net transfer of cytosolic NADH into mitochondria to maintain a high rate of glycolysis and to support rapid tumor cell growth. The malate–aspartate shuttle is operated by two pairs of enzymes that localize to the mitochondria and cytoplasm, glutamate oxaloacetate transaminases (GOT), and malate dehydrogenases (MDH). Here, we show that mitochondrial GOT2 is acetylated and that deacetylation depends on mitochondrial SIRT3. We have identified that acetylation occurs at three lysine residues, K159, K185, and K404 (3K), and enhances the association between GOT2 and MDH2. The GOT2 acetylation at these three residues promotes the net transfer of cytosolic NADH into mitochondria and changes the mitochondrial NADH/NAD+ redox state to support ATP production. Additionally, GOT2 3K acetylation stimulates NADPH production to suppress ROS and to protect cells from oxidative damage. Moreover, GOT2 3K acetylation promotes pancreatic cell proliferation and tumor growth in vivo. Finally, we show that GOT2 K159 acetylation is increased in human pancreatic tumors, which correlates with reduced SIRT3 expression. Our study uncovers a previously unknown mechanism by which GOT2 acetylation stimulates the malate–aspartate NADH shuttle activity and oxidative protection. PMID:25755250

  18. SIRT3-dependent GOT2 acetylation status affects the malate-aspartate NADH shuttle activity and pancreatic tumor growth.

    Science.gov (United States)

    Yang, Hui; Zhou, Lisha; Shi, Qian; Zhao, Yuzheng; Lin, Huaipeng; Zhang, Mengli; Zhao, Shimin; Yang, Yi; Ling, Zhi-Qiang; Guan, Kun-Liang; Xiong, Yue; Ye, Dan

    2015-04-15

    The malate-aspartate shuttle is indispensable for the net transfer of cytosolic NADH into mitochondria to maintain a high rate of glycolysis and to support rapid tumor cell growth. The malate-aspartate shuttle is operated by two pairs of enzymes that localize to the mitochondria and cytoplasm, glutamate oxaloacetate transaminases (GOT), and malate dehydrogenases (MDH). Here, we show that mitochondrial GOT2 is acetylated and that deacetylation depends on mitochondrial SIRT3. We have identified that acetylation occurs at three lysine residues, K159, K185, and K404 (3K), and enhances the association between GOT2 and MDH2. The GOT2 acetylation at these three residues promotes the net transfer of cytosolic NADH into mitochondria and changes the mitochondrial NADH/NAD(+) redox state to support ATP production. Additionally, GOT2 3K acetylation stimulates NADPH production to suppress ROS and to protect cells from oxidative damage. Moreover, GOT2 3K acetylation promotes pancreatic cell proliferation and tumor growth in vivo. Finally, we show that GOT2 K159 acetylation is increased in human pancreatic tumors, which correlates with reduced SIRT3 expression. Our study uncovers a previously unknown mechanism by which GOT2 acetylation stimulates the malate-aspartate NADH shuttle activity and oxidative protection. © 2015 The Authors.

  19. A novel potentiometric method for the determination of real crosslinking ratio of poly(aspartic acid) gels.

    Science.gov (United States)

    Torma, Viktória; Gyenes, Tamás; Szakács, Zoltán; Zrínyi, Miklós

    2010-03-01

    In order to obtain nontoxic functional polymer gels for biomedical applications, chemically crosslinked poly(aspartic acid) gels have been prepared using 1,4-diaminobutane as crosslinker. The presence of COOH and amino groups on the network chains renders these gels pH sensitive. Due to the specific hydrophobic-hydrophilic balance, these gels show a significant volume transition at a well-defined pH close to the pK value of uncrosslinked poly(aspartic acid). Since the magnitude of volume change critically depends on the degree of crosslinking, it is an important task to determine the topological characteristics of these networks. A novel method based on potentiometric acid-base titration has been developed to assess the crosslinking ratio, excluding physical crosslinks and entanglements. It turned out that only 25% of all crosslinker molecules forms real crosslinks between the poly(aspartic acid) chains; the rest react with one of its functional groups and forms short pendant side chains. At a nominal crosslinking ratio of 0.1, the number average molecular mass between crosslinks is found to be M(c) = 2300. Copyright 2010. Published by Elsevier Ltd.

  20. Endothelin-1 stimulates the release of preloaded ( sup 3 H)D-aspartate from cultured cerebellar granule cells

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    Lin, W.W.; Lee, C.Y.; Chuang, D.M. (NIMH Neuroscience Center, Washington, DC (USA))

    1990-03-16

    We have recently reported that endothelin-1 (ET) induces phosphoinositide hydrolysis in primary cultures of rat cerebellar granule cells. Here we found that ET in a dose-dependent manner (1-30 nM) stimulated the release of preloaded ({sup 3}H)D-aspartate from granule cells. The ET-induced aspartate release was completely blocked in the absence of extracellular Ca{sup 2+}, but was unaffected by 1 mM Co{sup 2+} or 1 microM dihydropyridine derivatives (nisoldipine and nimodipine). At higher concentration (10 microM) of nisoldipine and nimodipine, the release was partially inhibited. Short-term pretreatment of cells with phorbol 12,13-dibutyrate (PDBu) potentiated the ET-induced aspartate release, while long-term pretreatment with PDBu attenuated the release. Long-term exposure of cells to pertussis toxin (PTX), on the other hand, potentiated the ET-induced effects. Our results suggest that ET has a neuromodulatory function in the central nervous system.

  1. Suppressing N-Acetyl-l-Aspartate Synthesis Prevents Loss of Neurons in a Murine Model of Canavan Leukodystrophy.

    Science.gov (United States)

    Sohn, Jiho; Bannerman, Peter; Guo, Fuzheng; Burns, Travis; Miers, Laird; Croteau, Christopher; Singhal, Naveen K; McDonough, Jennifer A; Pleasure, David

    2017-01-11

    Canavan disease is a leukodystrophy caused by aspartoacylase (ASPA) deficiency. The lack of functional ASPA, an enzyme enriched in oligodendroglia that cleaves N-acetyl-l-aspartate (NAA) to acetate and l-aspartic acid, elevates brain NAA and causes "spongiform" vacuolation of superficial brain white matter and neighboring gray matter. In children with Canavan disease, neuroimaging shows early-onset dysmyelination and progressive brain atrophy. Neuron loss has been documented at autopsy in some cases. Prior studies have shown that mice homozygous for the Aspa nonsense mutation Nur7 also develop brain vacuolation. We now report that numbers of cerebral cortical and cerebellar neurons are decreased and that cerebral cortex progressively thins in AspaNur7/Nur7 mice. This neuronal pathology is prevented by constitutive disruption of Nat8l, which encodes the neuronal NAA-synthetic enzyme N-acetyltransferase-8-like. This is the first demonstration of cortical and cerebellar neuron depletion and progressive cerebral cortical thinning in an animal model of Canavan disease. Genetic suppression of N-acetyl-l-aspartate (NAA) synthesis, previously shown to block brain vacuolation in aspartoacylase-deficient mice, also prevents neuron loss and cerebral cortical atrophy in these mice. These results suggest that lowering the concentration of NAA in the brains of children with Canavan disease would prevent or slow progression of neurological deficits. Copyright © 2017 the authors 0270-6474/17/370413-09$15.00/0.

  2. Current status on metabolic engineering for the production of l-aspartate family amino acids and derivatives.

    Science.gov (United States)

    Li, Yanjun; Wei, Hongbo; Wang, Ting; Xu, Qingyang; Zhang, Chenglin; Fan, Xiaoguang; Ma, Qian; Chen, Ning; Xie, Xixian

    2017-12-01

    The l-aspartate amino acids (AFAAs) are constituted of l-aspartate, l-lysine, l-methionine, l-threonine and l-isoleucine. Except for l-aspartate, AFAAs are essential amino acids that cannot be synthesized by humans and most farm animals, and thus possess wide applications in food, animal feed, pharmaceutical and cosmetics industries. To date, a number of amino acids, including AFAAs have been industrially produced by microbial fermentation. However, the overall metabolic and regulatory mechanisms of the synthesis of AFAAs and the recent progress on strain construction have rarely been reviewed. Aiming to promote the establishment of strains of Corynebacterium glutamicum and Escherichia coli, the two industrial amino acids producing bacteria, that are capable of producing high titers of AFAAs and derivatives, this paper systematically summarizes the current progress on metabolic engineering manipulations in both central metabolic pathways and AFAA synthesis pathways based on the category of the five-word strain breeding strategies: enter, flow, moderate, block and exit. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Free D-aspartate regulates neuronal dendritic morphology, synaptic plasticity, gray matter volume and brain activity in mammals

    Science.gov (United States)

    Errico, F; Nisticò, R; Di Giorgio, A; Squillace, M; Vitucci, D; Galbusera, A; Piccinin, S; Mango, D; Fazio, L; Middei, S; Trizio, S; Mercuri, N B; Teule, M A; Centonze, D; Gozzi, A; Blasi, G; Bertolino, A; Usiello, A

    2014-01-01

    D-aspartate (D-Asp) is an atypical amino acid, which is especially abundant in the developing mammalian brain, and can bind to and activate N-methyl-D-Aspartate receptors (NMDARs). In line with its pharmacological features, we find that mice chronically treated with D-Asp show enhanced NMDAR-mediated miniature excitatory postsynaptic currents and basal cerebral blood volume in fronto-hippocampal areas. In addition, we show that both chronic administration of D-Asp and deletion of the gene coding for the catabolic enzyme D-aspartate oxidase (DDO) trigger plastic modifications of neuronal cytoarchitecture in the prefrontal cortex and CA1 subfield of the hippocampus and promote a cytochalasin D-sensitive form of synaptic plasticity in adult mouse brains. To translate these findings in humans and consistent with the experiments using Ddo gene targeting in animals, we performed a hierarchical stepwise translational genetic approach. Specifically, we investigated the association of variation in the gene coding for DDO with complex human prefrontal phenotypes. We demonstrate that genetic variation predicting reduced expression of DDO in postmortem human prefrontal cortex is mapped on greater prefrontal gray matter and activity during working memory as measured with MRI. In conclusion our results identify novel NMDAR-dependent effects of D-Asp on plasticity and physiology in rodents, which also map to prefrontal phenotypes in humans. PMID:25072322

  4. The crystal structure of the secreted aspartic protease 1 from Candida parapsilosis in complex with pepstatin A

    Energy Technology Data Exchange (ETDEWEB)

    Dostál, Ji& #345; í; Brynda, Ji& #345; í; Hrušková-Heidingsfeldová, Olga; Sieglová, Irena; Pichová, Iva; & #344; ezá& #269; ová, Pavlína; (ASCR-ICP)

    2010-09-01

    Opportunistic pathogens of the genus Candida cause infections representing a major threat to long-term survival of immunocompromised patients. Virulence of the Candida pathogens is enhanced by production of extracellular proteolytic enzymes and secreted aspartic proteases (Saps) are therefore studied as potential virulence factors and possible targets for therapeutic drug design. Candida parapsilosis is less invasive than C. albicans, however, it is one of the leading causative agents of yeast infections. We report three-dimensional crystal structure of Sapp1p from C. parapsilosis in complex with pepstatin A, the classical inhibitor of aspartic proteases. The structure of Sapp1p was determined from protein isolated from its natural source and represents the first structure of Sap from C. parapsilosis. Overall fold and topology of Sapp1p is very similar to the archetypic fold of monomeric aspartic protease family and known structures of Sap isoenzymes from C. albicans and Sapt1p from C. tropicalis. Structural comparison revealed noticeable differences in the structure of loops surrounding the active site. This resulted in differential character, shape, and size of the substrate binding site explaining divergent substrate specificities and inhibitor affinities. Determination of structures of Sap isoenzymes from various species might contribute to the development of new Sap-specific inhibitors.

  5. Atomic coordination reflects peptide immunogenicity

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    Georgios S.E. Antipas

    2016-01-01

    Full Text Available We demonstrated that the immunological identity of variant peptides may be accurately predicted on the basis of atomic coordination of both unprotonated and protonated tertiary structures, provided that the structure of the native peptide (index is known. The metric which was discovered to account for this discrimination is the coordination difference between the variant and the index; we also showed that increasing coordination difference in respect to the index was correlated to a correspondingly weakening immunological outcome of the variant. Additionally, we established that this metric quickly seizes to operate beyond the peptide scale, e.g. over a coordination shell inclusive of atoms up to a distance of 7 Å away from the peptide or over the entire pMHC-TCR complex. Analysis of molecular orbital interactions over a range of formal charges further revealed that the N-terminus of the agonists was always able to sustain a stable ammonium (NH3+ group which was consistently absent in antagonists. We deem that the presence of NH3+ constitutes a secondary observable with a biological consequence, signifying a change in T cell activation. While our analysis of protonated structures relied on the quantum chemical relaxation of the H species, the results were consistent over a wide range of peptide charge and spin polarization conditions.

  6. Redox potentials of dopamine and its supramolecular complex with aspartic acid

    Science.gov (United States)

    Liu, Tao; Han, Ling-Li; Du, Chun-Mei; Yu, Zhang-Yu

    2014-07-01

    Dopamine (DA) can be oxidized to dopamine quinone (DAquinone) through a one-step, two-electron redox reaction. The electron transfer property of DA and its supramolecular complex with aspartic acid (Asp) has been investigated by the theoretical calculations. We calculated the standard redox potentials ( E o) of DA/DAquinone at the MP2/6-31G( d,p)//B3LYP/6-31G( d,p), MP2/6-31+G( d,p)//B3LYP/6-31+G( d,p), MP2/6-31G( d,p)//B3LYP/6-311G( d,p), and MP2/6-311+G( d,p)//B3LYP/6-311+G( d,p) levels. Comparing the experimental value, the redox potentials of DA/DAquinone obtained at MP2//B3LYP/6-311G( d,p) and MP2//B3LYP/6-311+G( d,p) levels can be considered as the upper and lower estimates. DA can form supramolecular complex (DA-Asp) with Asp through hydrogen bond (H-bond). Therefore, the values of 0.631 and 0.628 V obtained at MP2//B3LYP/6-311G( d,p) and MP2//B3LYP/6-311+G( d,p) levels for DA-Asp/DAquinone-Asp can be proposed as the upper and lower estimates of a probable (about 0.630 V) value of the corresponding redox potential. The calculated E o values of DA-Asp/DAquinone-Asp at the four theoretical levels are upper than those of DA/DAquinone, which indicates that the formation of H-bonds weaken the electron-donating ability of DA.

  7. Thiolactomycin inhibits D-aspartate oxidase: a novel approach to probing the active site environment.

    Science.gov (United States)

    Katane, Masumi; Saitoh, Yasuaki; Hanai, Toshihiko; Sekine, Masae; Furuchi, Takemitsu; Koyama, Nobuhiro; Nakagome, Izumi; Tomoda, Hiroshi; Hirono, Shuichi; Homma, Hiroshi

    2010-10-01

    D-Aspartate oxidase (DDO) and D-amino acid oxidase (DAO) are flavin adenine dinucleotide (FAD)-containing flavoproteins that catalyze the oxidative deamination of D-amino acids. While several functionally and structurally important amino acid residues have been identified in the DAO protein, little is known about the structure-function relationships of DDO. In the search for a potent DDO inhibitor as a novel tool for investigating its structure-function relationships, a large number of biologically active compounds of microbial origin were screened for their ability to inhibit the enzymatic activity of mouse DDO. We discovered several compounds that inhibited the activity of mouse DDO, and one of the compounds identified, thiolactomycin (TLM), was then characterized and evaluated as a novel DDO inhibitor. TLM reversibly inhibited the activity of mouse DDO with a mixed type of inhibition more efficiently than meso-tartrate and malonate, known competitive inhibitors of mammalian DDOs. The selectivity of TLM was investigated using various DDOs and DAOs, and it was found that TLM inhibits not only DDO, but also DAO. Further experiments with apoenzymes of DDO and DAO revealed that TLM is most likely to inhibit the activities of DDO and DAO by competition with both the substrate and the coenzyme, FAD. Structural models of mouse DDO/TLM complexes supported this finding. The binding mode of TLM to DDO was validated further by site-directed mutagenesis of an active site residue, Arg-237. Collectively, our findings show that TLM is a novel, active site-directed DDO inhibitor that will be useful for elucidating the molecular details of the active site environment of DDO. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  8. N-Methyl D-Aspartic Acid (NMDA Receptors and Depression

    Directory of Open Access Journals (Sweden)

    Enver Yusuf Sivrioglu

    2009-06-01

    Full Text Available The monoaminergic hypothesis of depression has provided the basis for extensive research into the pathophysiology of mood disorders and has been of great significance for the development of effective antidepressants. Current antidepressant treatments not only increase serotonin and/or noradrenaline bioavailability but also originate adaptive changes increasing synaptic plasticity. Novel approaches to depression and to antidepressant therapy are now focused on intracellular targets that regulate neuroplasticity and cell survival. Accumulating evidence indicates that there is an anatomical substrate for such a devastating neuropsychiatric disease as major depression. Loss of synaptic plasticity and hippocampal atrophy appear to be prominent features of this highly prevalent disorder. A combination of genetic susceptibility and environmental factors make hippocampal neurons more vulnerable to stress. Abundant experimental evidence indicates that stress causes neuronal damage in brain regions, notably in hippocampal subfields. Stress-induced activation of glutamatergic transmission may induce neuronal cell death through excessive stimulation of N-methyl-D-aspartic acid (NMDA receptors. Recent studies mention that the increase of nitric oxide synthesis and inflammation in major depression may contribute to neurotoxicity through NMDA receptor. Both standard antidepressants and NMDA receptor antagonists are able to prevent stress-induced neuronal damage. NMDA antagonists are effective in widely used animal models of depression and some of them appear to be effective also in the few clinical trials performed to date. We are still far from understanding the complex cellular and molecular events involved in mood disorders. There appears to be an emerging role for glutamate neurotransmission in the search for the pathogenesis of major depression. Attenuation of NMDA receptor function mechanism appears to be a promising target in the search for a more

  9. Distribution of serum concentrations reported for macroenzyme aspartate aminotransferase (macro-AST).

    Science.gov (United States)

    Rubin, Asa S; Sass, David A; Stickle, Douglas F

    2017-08-01

    The presence of macroenzyme (M) is often the explanation of an isolated elevation of aspartate aminotransferase (AST). Where M is identified, it is reasonable for the clinician to ask where an individual patient's result fits in with known concentrations of M. In this context, we conducted a survey of literature to examine the distribution of reported serum concentrations of macro-AST. We also analyzed the distribution data to examine whether elevations were consistent with simple alteration of circulatory half-life (t1/2) of M relative to normal AST. Distributions of M were compiled from the literature. These distributions were compared to predictions based on fixed changes in t1/2 applied to the reference interval for AST. There was a bimodal distribution of literature values for M (n =51), comprised roughly of populations A (M 200 U/L; 40% of total). The two distributions were reasonably well characterized by a simple projection to the right of the reference interval for AST according to increased t1/2 (A: t1/2 =3.3 days; B: t1/2 =19.8 days) relative to AST (t1/2 =0.7 days). Knowledge of distributions for M may be useful in discussion with clinicians regarding significance of M for individual patients. Distributions for M were consistent with the simplest explanation for elevated AST due strictly to an extended circulatory lifetime for M. Caveats to analysis, however, include selection within literature data mainly for patients with various co-morbidities.

  10. Antipsychotic agents antagonize non-competitive N-methyl-D-aspartate antagonist-induced behaviors.

    Science.gov (United States)

    Corbett, R; Camacho, F; Woods, A T; Kerman, L L; Fishkin, R J; Brooks, K; Dunn, R W

    1995-07-01

    Antipsychotic agents were tested for their ability to antagonize both dopaminergic-induced and non-competitive N-methyl-D-aspartate (NMDA) antagonist-induced behaviors. All of the agents dose-dependently antagonized the apomorphine-induced climbing mouse assay (CMA) and dizocilpine (MK-801)-induced locomotion and falling assay (MK-801-LF) with a CMA/MK-801-LF ratio of less than or equal to 1.6. However, clozapine and its structural analog olanzapine more potently antagonized MK-801-LF (1.1 and 0.05 mg/kg) than the CMA (12.3 and 0.45 mg/kg) and as a result had a CMA/MK-801-LF ratio of 11.2 and 9, respectively. Furthermore, phencyclidine (PCP) (2 mg/kg) can selectively induce social withdrawal in naive rats that were housed in pairs (familiar) for 10 days prior to testing without affecting motor activity. SCH 23390, raclopride, haloperidol, chlorpromazine and risperidone failed to reverse the social withdrawal induced by PCP up to doses which produced significant motor impairment. However, clozapine (2.5 and 5.0 mg/kg) and olanzapine (0.25 and 0.5 mg/kg) significantly reversed this social withdrawal in rats. Therefore, the non-competitive NMDA antagonists PCP and MK-801 can induce behaviors in Rodents which are selectively antagonized by clozapine and olanzapine. Furthermore, assessment of the effects of antipsychotic agents in the CMA, MK-801-LF and PCP-induced social withdrawal assays may provide a preclinical approach to identify novel agents for negative symptoms and treatment resistant schizophrenia.

  11. Comparative analysis of aspartic acid racemization methods using whole-tooth and dentin samples.

    Science.gov (United States)

    Sakuma, Ayaka; Ohtani, Susumu; Saitoh, Hisako; Iwase, Hirotaro

    2012-11-30

    One way to estimate biological age is to use the aspartic acid (Asp) racemization method. Although this method has been performed mostly using enamel and dentin, we investigated whether an entire tooth can be used for age estimation. This study used 12 pairs of canines extracted from both sides of the mandible of 12 individuals of known age. From each pair, one tooth was used as a dentin sample and the other as a whole-tooth sample. Amino acids were extracted from each sample, and the integrated peak areas of D-Asp and L-Asp were determined using a gas chromatograph/mass spectrometer. Statistical analysis was performed using the D/L-Asp ratio. Furthermore, teeth from two unidentified bodies, later identified as Japanese and Brazilian, were examined in the same manner. Results showed that the D/L ratios of whole-tooth samples were higher overall than those of dentin samples. The correlation coefficient between the D/L ratios of dentin samples and their age was r=0.98, and that of the whole-tooth samples was r=0.93. The difference between estimated age and actual chronological age was -0.116 and -6.86 years in the Japanese and Brazilian cases, respectively. The use of whole teeth makes the racemization technique easier and can standardize the sampling site. Additionally, using only a few tooth samples per analysis made it possible to reanalyze known-age samples. Although the difficulty in obtaining a proper control sample has prevented racemization from being widely used, the method described here not only ensures the availability of a control tooth, but also enables the teeth to be used for other purposes such as DNA analysis. The use of a whole tooth will increase the application of the racemization technique for age determination. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Anti-N-methyl-D-aspartate-receptor encephalitis: diagnosis, optimal management, and challenges

    Directory of Open Access Journals (Sweden)

    Mann AP

    2014-07-01

    Full Text Available Andrea P Mann,1 Elena Grebenciucova,2 Rimas V Lukas21Department of Psychiatry and Behavioral Neuroscience, 2Department of Neurology, University of Chicago, Chicago, IL, USAObjective: Anti-N-methyl-D-aspartate-receptor (NMDA-R encephalitis is a new autoimmune disorder, often paraneoplastic in nature, presenting with complex neuropsychiatric symptoms. Diagnosed serologically, this disorder is often responsive to immunosuppressant treatment. The objective of this review is to educate clinicians on the challenges of diagnosis and management of this disorder.Materials and methods: A review of the relevant literature on clinical presentation, pathophysiology, and recommended management was conducted using a PubMed search. Examination of the results identified articles published between 2007 and 2014.Results: The literature highlights the importance of recognizing early common signs and symptoms, which include hallucinations, seizures, altered mental status, and movement disorders, often in the absence of fever. Although the presence of blood and/or cerebrospinal fluid autoantibodies confirms diagnosis, approximately 15% of patients have only positive cerebrospinal fluid titers. Antibody detection should prompt a search for an underlying teratoma or other underlying neoplasm and the initiation of first-line immunosuppressant therapy: intravenous methylprednisolone, intravenous immunoglobulin, or plasmapheresis, or a combination thereof. Second-line treatment with rituximab or cyclophosphamide should be implemented if no improvement is noted after 10 days. Complications can include behavioral problems (eg, aggression and insomnia, hypoventilation, catatonia, and autonomic instability. Those patients who can be managed outside an intensive care unit and whose tumors are identified and removed typically have better rates of remission and functional outcomes.Conclusion: There is an increasing need for clinicians of different specialties, including

  13. Selective vulnerabilities of N-methyl-D-aspartate (NMDA receptors during brain aging

    Directory of Open Access Journals (Sweden)

    Brenna L Brim

    2010-03-01

    Full Text Available N-methyl-D-aspartate (NMDA receptors are present in high density within the cerebral cortex and hippocampus and play an important role in learning and memory. NMDA receptors are negatively affected by aging, but these effects are not uniform in many different ways. This review discusses the selective age-related vulnerabilities of different binding sites of the NMDA receptor complex, different subunits that comprise the complex, and the expression and functions of the receptor within different brain regions. Spatial reference, passive avoidance, and working memory, as well as place field stability and expansion all involve NMDA receptors. Aged animals show deficiencies in these functions, as compared to young, and some studies have identified an association between age-associated changes in the expression of NMDA receptors and poor memory performance. A number of diet and drug interventions have shown potential for reversing or slowing the effects of aging on the NMDA receptor. On the other hand, there is mounting evidence that the NMDA receptors that remain within aged individuals are not always associated with good cognitive functioning. This may be due to a compensatory response of neurons to the decline in NMDA receptor expression or a change in the subunit composition of the remaining receptors. These studies suggest that developing treatments that are aimed at preventing or reversing the effects of aging on the NMDA receptor may aid in ameliorating the memory declines that are associated with aging. However, we need to be mindful of the possibility that there may also be negative consequences in aged individuals.

  14. Overlapping demyelinating syndromes and anti–N-methyl-D-aspartate receptor encephalitis.

    Science.gov (United States)

    Titulaer, Maarten J; Höftberger, Romana; Iizuka, Takahiro; Leypoldt, Frank; McCracken, Lindsey; Cellucci, Tania; Benson, Leslie A; Shu, Huidy; Irioka, Takashi; Hirano, Makito; Singh, Gagandeep; Cobo Calvo, Alvaro; Kaida, Kenichi; Morales, Pamela S; Wirtz, Paul W; Yamamoto, Tomotaka; Reindl, Markus; Rosenfeld, Myrna R; Graus, Francesc; Saiz, Albert; Dalmau, Josep

    2014-03-01

    To report the clinical, radiological, and immunological association of demyelinating disorders with anti–Nmethyl- D-aspartate receptor (NMDAR) encephalitis. Clinical and radiological analysis was done of a cohort of 691 patients with anti-NMDAR encephalitis. Determination of antibodies to NMDAR, aquaporin-4 (AQP4), and myelin oligodendrocyte glycoprotein (MOG) was performed using brain immunohistochemistry and cell-based assays. Twenty-three of 691 patients with anti-NMDAR encephalitis had prominent magnetic resonance imaging (MRI) and/or clinical features of demyelination. Group 1 included 12 patients in whom anti-NMDAR encephalitis was preceded or followed by independent episodes of neuromyelitis optica (NMO) spectrum disorder (5 cases, 4 anti-AQP4 positive) or brainstem or multifocal demyelinating syndromes (7 cases, all anti-MOG positive). Group 2 included 11 patients in whom anti-NMDAR encephalitis occurred simultaneously with MRI and symptoms compatible with demyelination (5 AQ4 positive, 2 MOG positive). Group 3 (136 controls) included 50 randomly selected patients with typical anti-NMDAR encephalitis, 56 with NMO, and 30 with multiple sclerosis; NMDAR antibodies were detected only in the 50 anti-NMDAR patients, MOG antibodies in 3 of 50 anti-NMDAR and 1 of 56 NMO patients, and AQP4 antibodies in 48 of 56 NMO and 1 of 50 anti-NMDAR patients (pdemyelinating episodes required more intensive therapy and resulted in more residual deficits. Only 1 of 23 NMDAR patients with signs of demyelination had ovarian teratoma compared with 18 of 50 anti-NMDAR controls (p50.011). Patients with anti-NMDAR encephalitis may develop concurrent or separate episodes of demyelinating disorders, and conversely patients with NMO or demyelinating disorders with atypical symptoms (eg, dyskinesias, psychosis) may have anti-NMDAR encephalitis.

  15. Candida albicans possesses Sap7 as a pepstatin A-insensitive secreted aspartic protease.

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    Wataru Aoki

    Full Text Available BACKGROUND: Candida albicans, a commensal organism, is a part of the normal flora of healthy individuals. However, once the host immunity is compromised, C. albicans opportunistically causes recurrent superficial or fatal systemic candidiasis. Secreted aspartic proteases (Sap, encoded by 10 types of SAP genes, have been suggested to contribute to various virulence processes. Thus, it is important to elucidate their biochemical properties for better understanding of the molecular mechanisms that how Sap isozymes damage host tissues. METHODOLOGY/PRINCIPAL FINDINGS: The SAP7 gene was cloned from C. albicans SC5314 and heterogeneously produced by Pichia pastoris. Measurement of Sap7 proteolytic activity using the FRETS-25Ala library showed that Sap7 was a pepstatin A-insensitive protease. To understand why Sap7 was insensitive to pepstatin A, alanine substitution mutants of Sap7 were constructed. We found that M242A and T467A mutants had normal proteolytic activity and sensitivity to pepstatin A. M242 and T467 were located in close proximity to the entrance to an active site, and alanine substitution at these positions widened the entrance. Our results suggest that this alteration might allow increased accessibility of pepstatin A to the active site. This inference was supported by the observation that the T467A mutant has stronger proteolytic activity than the wild type. CONCLUSIONS/SIGNIFICANCE: We found that Sap7 was a pepstatin A-insensitive protease, and that M242 and T467 restricted the accessibility of pepstatin A to the active site. This finding will lead to the development of a novel protease inhibitor beyond pepstatin A. Such a novel inhibitor will be an important research tool as well as pharmaceutical agent for patients suffering from candidiasis.

  16. Arginine-glycine-aspartic acid functional branched semi-interpenetrating hydrogels.

    Science.gov (United States)

    Plenderleith, Richard A; Pateman, Christopher J; Rodenburg, Cornelia; Haycock, John W; Claeyssens, Frederik; Sammon, Chris; Rimmer, Stephen

    2015-10-14

    For the first time a series of functional hydrogels based on semi-interpenetrating networks with both branched and crosslinked polymer components have been prepared and we show the successful use of these materials as substrates for cell culture. The materials consist of highly branched poly(N-isopropyl acrylamide)s with peptide functionalised end groups in a continuous phase of crosslinked poly(vinyl pyrrolidone). Functionalisation of the end groups of the branched polymer component with the GRGDS peptide produces a hydrogel that supports cell adhesion and proliferation. The materials provide a new synthetic functional biomaterial that has many of the features of extracellular matrix, and as such can be used to support tissue regeneration and cell culture. This class of high water content hydrogel material has important advantages over other functional hydrogels in its synthesis and does not require post-processing modifications nor are functional-monomers, which change the polymerisation process, required. Thus, the systems are amenable to large scale and bespoke manufacturing using conventional moulding or additive manufacturing techniques. Processing using additive manufacturing is exemplified by producing tubes using microstereolithography.

  17. Delivery systems for antimicrobial peptides

    DEFF Research Database (Denmark)

    Nordström, Randi; Malmsten, Martin

    2017-01-01

    are likely to play a key role in the development of potent and safe AMP-based therapeutics, e.g., through reducing chemical or biological degradation of AMPs either in the formulation or after administration, by reducing adverse side-effects, by controlling AMP release rate, by promoting biofilm penetration......Due to rapidly increasing resistance development against conventional antibiotics, finding novel approaches for the treatment of infections has emerged as a key health issue. Antimicrobial peptides (AMPs) have attracted interest in this context, and there is by now a considerable literature...... on the identification such peptides, as well as on their optimization to reach potent antimicrobial and anti-inflammatory effects at simultaneously low toxicity against human cells. In comparison, delivery systems for antimicrobial peptides have attracted considerably less interest. However, such delivery systems...

  18. Antimicrobial Peptides from Marine Proteobacteria

    Directory of Open Access Journals (Sweden)

    Yannick Fleury

    2013-09-01

    Full Text Available After years of inadequate use and the emergence of multidrug resistant (MDR strains, the efficiency of “classical” antibiotics has decreased significantly. New drugs to fight MDR strains are urgently needed. Bacteria hold much promise as a source of unusual bioactive metabolites. However, the potential of marine bacteria, except for Actinomycetes and Cyanobacteria, has been largely underexplored. In the past two decades, the structures of several antimicrobial compounds have been elucidated in marine Proteobacteria. Of these compounds, polyketides (PKs, synthesised by condensation of malonyl-coenzyme A and/or acetyl-coenzyme A, and non-ribosomal peptides (NRPs, obtained through the linkage of (unusual amino acids, have recently generated particular interest. NRPs are good examples of naturally modified peptides. Here, we review and compile the data on the antimicrobial peptides isolated from marine Proteobacteria, especially NRPs.

  19. Dietary bioactive peptides: Human studies.

    Science.gov (United States)

    Bouglé, Dominique; Bouhallab, Saïd

    2017-01-22

    Current opinion strongly links nutrition and health. Among nutrients, proteins, and peptides which are encrypted in their sequences and released during digestion could play a key role in improving health. These peptides have been claimed to be active on a wide spectrum of biological functions or diseases, including blood pressure and metabolic risk factors (coagulation, obesity, lipoprotein metabolism, and peroxidation), gut and neurological functions, immunity, cancer, dental health, and mineral metabolism. A majority of studies involved dairy peptides, but the properties of vegetal, animal, and sea products were also assessed. However, these allegations are mainly based on in vitro and experimental studies which are seldom confirmed in humans. This review focused on molecules which were tested in humans, and on the mechanisms explaining discrepancies between experimental and human studies.

  20. Neoglycolipidation for modulating peptide properties

    DEFF Research Database (Denmark)

    van Witteloostuijn, Søren Blok

    regulation of appetite, food intake, and glucose homeostasis, and many of these peptides display a signicant potential for treatment of obesity and/or type 2 diabetes. This Ph.D. thesis describes three novel approaches for utilizing gut peptides as the starting point for developing obesity and diabetes drugs....... In addition, neoglycolipidation led to selfassembly and formation of well-dened oligomers as well as non-covalent binding to human serum albumin. In lean mice, acute treatment of lean mice with the neoglycolipidated GLP-1 analogs provided a marked improvement of glucose homeostasis and a potent inhibition......The alarming increase in the prevalence of obesity and associated comorbidities such as type 2 diabetes emphasizes the urgent need for new drugs with both anorectic and antidiabetic eects. Several peptide hormones secreted from the gastrointestinal tract play an important role in the physiological...

  1. A self-replicating peptide

    Science.gov (United States)

    Lee, David H.; Granja, Juan R.; Martinez, Jose A.; Severin, Kay; Ghadiri, M. Reza

    1996-08-01

    THE production of amino acids and their condensation to polypeptides under plausibly prebiotic conditions have long been known1,2. But despite the central importance of molecular self-replication in the origin of life, the feasibility of peptide self-replication has not been established experimentally3-6. Here we report an example of a self-replicating peptide. We show that a 32-residue α-helical peptide based on the leucine-zipper domain of the yeast transcription factor GCN4 can act autocatalytically in templating its own synthesis by accelerating the thioester-promoted amide-bond condensation of 15- and 17-residue fragments in neutral, dilute aqueous solutions. The self-replication process displays parabolic growth pattern with the initial rates of product formation correlating with the square-root of initial template concentration.

  2. The Pig PeptideAtlas

    DEFF Research Database (Denmark)

    Hesselager, Marianne Overgaard; Codrea, Marius; Sun, Zhi

    2016-01-01

    Biological research of Sus scrofa, the domestic pig, is of immediate relevance for food production sciences, and for developing pig as a model organism for human biomedical research. Publicly available data repositories play a fundamental role for all biological sciences, and protein data...... repositories are in particular essential for the successful development of new proteomic methods. Cumulative proteome data repositories, including the PeptideAtlas, provide the means for targeted proteomics, system-wide observations, and cross-species observational studies, but pigs have so far been...... underrepresented in existing repositories. We here present a significantly improved build of the Pig PeptideAtlas, which includes pig proteome data from 25 tissues and three body fluid types mapped to 7139 canonical proteins. The content of the Pig PeptideAtlas reflects actively ongoing research within...

  3. Valorisation of tuna processing waste biomass for recovery of functional and antioxidant peptides using enzymatic hydrolysis and membrane fractionation process.

    Science.gov (United States)

    Saidi, Sami; Ben Amar, Raja

    2016-10-01

    The enzymatic hydrolysis using Prolyve BS coupled to membrane process (Ultrafiltration (UF) and nanofiltration (NF)) is a means of biotransformation of tuna protein waste to Tuna protein hydrolysate (TPH) with higher added values. This method could be an effective solution for the production of bioactive compounds used in various biotechnological applications and minimizing the pollution problems generated by the seafood processing industries. The amino acid composition, functional and antioxidant properties of produced TPH were evaluated. The results show that the glutamic acid, aspartic acid, glycine, alaline, valine and leucine were the major amino acids detected in the TPH profile. After membrane fractionation process, those major amino acids were concentrated in the NF retentate (NFR). The NFR and NF permeate (NFP) have a higher protein solubility (>95 %) when compared to TPH (80 %). Higher oil and water binding capacity were observed in TPH and higher emulsifying and foam stability was found in UF retentate. The NFP showed the highest DPPH radical scavenging activity (65 %). The NFR contained antioxidant amino acid (30.3 %) showed the highest superoxide radical and reducing power activities. The TPH showed the highest iron chelating activity (75 %) compared to other peptide fractions. The effect of the membrane fractionation on the molecular weight distribution of the peptide and their bioactivities was underlined. We concluded that the TPH is a valuable source of bioactive peptides and their peptide fractions may serve as useful ingredients for application in food industry and formulation of nutritional products.

  4. Role of the Aspartate Transaminase and Platelet Ratio Index in Assessing Hepatic Fibrosis and Liver Inflammation in Adolescent Patients with HBeAg-Positive Chronic Hepatitis B.

    Science.gov (United States)

    Zhijian, Yu; Hui, Li; Weiming, Yao; Zhanzhou, Lin; Zhong, Chen; Jinxin, Zheng; Hongyan, Wang; Xiangbin, Deng; Weizhi, Yang; Duoyun, Li; Xiaojun, Liu; Qiwen, Deng

    2015-01-01

    This study described an index of aspartate aminotransferase-to-platelet ratio index (APRI) to assess hepatic fibrosis with limited expense and widespread availability compared to the liver biopsy in adolescent patients with CHB.

  5. Role of the Aspartate Transaminase and Platelet Ratio Index in Assessing Hepatic Fibrosis and Liver Inflammation in Adolescent Patients with HBeAg-Positive Chronic Hepatitis B

    Directory of Open Access Journals (Sweden)

    Yu Zhijian

    2015-01-01

    Full Text Available This study described an index of aspartate aminotransferase-to-platelet ratio index (APRI to assess hepatic fibrosis with limited expense and widespread availability compared to the liver biopsy in adolescent patients with CHB.

  6. Fetal and perinatal outcomes in type 1 diabetes pregnancy: a randomized study comparing insulin aspart with human insulin in 322 subjects

    DEFF Research Database (Denmark)

    Hod, Moshe; Damm, Peter; Kaaja, Risto

    2008-01-01

    The objective of the study was a comparison of insulin aspart (IAsp) with human insulin (HI) in basal-bolus therapy with neutral protamine Hagedorn for fetal and perinatal outcomes of type 1 diabetes in pregnancy....

  7. Novel Formulations for Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2014-10-01

    Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  8. Novel Formulations for Antimicrobial Peptides

    Science.gov (United States)

    Carmona-Ribeiro, Ana Maria; Carrasco, Letícia Dias de Melo

    2014-01-01

    Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy. PMID:25302615

  9. Aspartic acid as an internal CO2 reservoir in Zea mays: Effect of oxygen concentration and of far-red illumination.

    Science.gov (United States)

    Créach, E; Michel, J P; Thibault, P

    1974-06-01

    By placing leaf segments first in CO2 in the dark, then in pure nitrogen either in the dark and afterwards in the light or immediately in the light, the existence of internal CO2 pools which can be used for photosynthesis had been demonstrated. In Zea mays L. there are two such pools: one which in the absence of any energy source is short-lived (t1/2 ca. 2 min), and another which is relatively long-lived (t1/2 ca. 50 min).Under different oxygen concentrations the level of the short-lived CO2 pool exibited a parallel variation with the level of aspartic acid. Only a fraction of the total aspartic acid (60%) constituted the active pool, the quantity of which was equal to the short-lived CO2. In the absence of O2 but under far-red irradiation (maximum 740 nm), a net synthesis of aspartic acid was observed; its extent depended on the intensity of the light.The similarity in the response to O2 and to long-wavelength irradiation suggests that aspartate synthesis is regulated by ATP, the high-energy compound common to both oxidative and cyclic phosphorylations. The formation of aspartic acid observed in the dark under N2+1% CO2 immediately following illumination under pure N2 suggests use of ATP accumulated in the preceding light period, in aspartate synthesis.Even though Zea mays is predominantly a "malate former", it appears that aspartate must also be considered as a readily available donor of CO2 since, when aspartate is present, O2 release is always immediate while, when it is not, O2 release is delayed.

  10. Antimicrobial peptides: old molecules with new ideas

    National Research Council Canada - National Science Library

    Nakatsuji, Teruaki; Gallo, Richard L

    2012-01-01

    .... So far, more than 1,200 types of peptides with antimicrobial activity have been isolated from various cells and tissues, and it appears that all living organisms use these antimicrobial peptides (AMPs...

  11. Histidine-Containing Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2000-01-01

    Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....

  12. Development of a novel fluorescent protein construct by genetically fusing green fluorescent protein to the N-terminal of aspartate dehydrogenase.

    Science.gov (United States)

    Ozyurt, Canan; Evran, Serap; Telefoncu, Azmi

    2013-01-01

    We developed a fluorescent protein construct by genetically fusing green fluorescent protein (GFP) to aspartate dehydrogenase from Thermotoga maritima. The fusion protein was cloned, heterologously expressed in Escherichia coli cells, and purified by Ni-chelate affinity chromatography. It was then introduced into a measurement cuvette to monitor its fluorescence signal. Aspartate dehydrogenase functioned as the biorecognition element, and aspartate-induced conformational change was converted to a fluorescence signal by GFP. The recombinant protein responded to l-aspartate (l-Asp) linearly within the concentration range of 1-50 mM, and it was capable of giving a fluorescence signal in 1 Min. Although a linear response was also observed for l-Glu, the fluorescence signal was 2.7 times lower than that observed for l-Asp. In the present study, we describe two novelties: development of a genetically encoded fluorescent protein construct for monitoring of l-Asp in vitro, and employment of aspartate dehydrogenase scaffold as a biorecognition element. A few genetically encoded amino-acid biosensors have been described in the literature, but to our knowledge, a protein has not been constructed solely for determination of l-Asp. Periplasmic ligand binding proteins offer high binding affinity in the micromolar range, and they are frequently used as biorecognition elements. Instead of choosing a periplasmic l-Asp binding protein, we attempted to use the substrate specificity of aspartate dehydrogenase enzyme. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  13. Tulane/Xavier Vaccine Peptide Program

    Science.gov (United States)

    2014-09-01

    identified a candidate anti -viral therapeutic peptide, designated Flufirvitide-3. We found that Flufirvitide-3 is a potent inhibitor of infections by...dispersed in an aqueous solution containing the flufirvitide peptide using Tween 80 and propylene glycol co- surfactants. This emulsion preparation is...concentration of peptide at the oil/water interface on the emulsion droplet surface will also improve the effectiveness of Flufirvitide-3 peptide as

  14. Peptides, polypeptides and peptide-polymer hybrids as nucleic acid carriers.

    Science.gov (United States)

    Ahmed, Marya

    2017-10-24

    Cell penetrating peptides (CPPs), and protein transduction domains (PTDs) of viruses and other natural proteins serve as a template for the development of efficient peptide based gene delivery vectors. PTDs are sequences of acidic or basic amphipathic amino acids, with superior membrane trespassing efficacies. Gene delivery vectors derived from these natural, cationic and cationic amphipathic peptides, however, offer little flexibility in tailoring the physicochemical properties of single chain peptide based systems. Owing to significant advances in the field of peptide chemistry, synthetic mimics of natural peptides are often prepared and have been evaluated for their gene expression, as a function of amino acid functionalities, architecture and net cationic content of peptide chains. Moreover, chimeric single polypeptide chains are prepared by a combination of multiple small natural or synthetic peptides, which imparts distinct physiological properties to peptide based gene delivery therapeutics. In order to obtain multivalency and improve the gene delivery efficacies of low molecular weight cationic peptides, bioactive peptides are often incorporated into a polymeric architecture to obtain novel 'polymer-peptide hybrids' with improved gene delivery efficacies. Peptide modified polymers prepared by physical or chemical modifications exhibit enhanced endosomal escape, stimuli responsive degradation and targeting efficacies, as a function of physicochemical and biological activities of peptides attached onto a polymeric scaffold. The focus of this review is to provide comprehensive and step-wise progress in major natural and synthetic peptides, chimeric polypeptides, and peptide-polymer hybrids for nucleic acid delivery applications.

  15. Development and use of engineered peptide deformylase in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia

    2012-01-01

    Deze thesis beschrijft het onderzoek naar potentieel van het gebruik van het peptide deformylase (PDF) in chemo enzymatische peptide synthese. PDF is geschikt voor selective N terminale deformylatie van bepaalde N-formyl-peptides zonder gelijktijdige hydrolyse van de peptide binding. Door de

  16. Comparison of pharmacokinetics between new quinolone antibiotics: the zabofloxacin hydrochloride capsule and the zabofloxacin aspartate tablet.

    Science.gov (United States)

    Han, Hyekyung; Kim, Sung Eun; Shin, Kwang-Hee; Lim, Cheolhee; Lim, Kyoung Soo; Yu, Kyung-Sang; Cho, Joo-Youn

    2013-10-01

    Zabofloxacin is being developed as a new fluoroquinolone antibiotic that is a potent and selective inhibitor of the essential bacterial type II topoisomerases and topoisomerase IV. Zabofloxacin is indicated for community-acquired respiratory infections due to Gram-positive bacteria. The aim of this study was to compare the pharmacokinetics (PK) of the zabofloxacin hydrochloride 400 mg capsule (DW224a, 366.7 mg as zabofloxacin) with the PK of the zabofloxacin aspartate 488 mg tablet (DW224aa, 366.5 mg as zabofloxacin) in healthy Korean male volunteers to assess the bioequivalence between the two drug formulations. A randomized, open-label, single-dose, two-way crossover study was performed. The subjects received either DW224a or DW224aa according to their sequence group. Plasma concentrations of zabofloxacin were determined by liquid chromatography-tandem mass spectrometry. The maximum plasma concentrations (Cmax), the area under the plasma concentration versus time curve (AUC) from the time of dosing to 48 hours post-dosing (AUClast), and the AUC extrapolated to infinity (AUCinf) were determined from the plasma concentration-time profile. (ClinicalTrials.gov identifier: NCT01341249). Twenty-nine of the 32 subjects enrolled completed the study. The Cmax. AUClast, and AUCinf (mean ± SD) values of DW224a were 1889.7 ± 493.4 ng/mL, 11,110  ± 2,005.0 ng h/mL, and 11,287 ± 2,012.6 ng h/mL, respectively, and those of DW224aa were 2005.0 ± 341.3 ng/mL, 11,719  ±  2,507.5 ng h/mL, and 11,913 ± 2,544.8 ng h/mL, respectively. The geometric mean ratios (90% confidence intervals) of the Cmax. AUClast, and AUCinf were 1.08 (1.00-1.17), 1.05 (1.00-1.10), and 1.05 (1.00-1.10), respectively, and were within the bioequivalence acceptance range of 0.8-1.25. Both drugs were well tolerated with no serious adverse events. A single oral dose of DW224a or DW224aa to healthy volunteers appeared to be well tolerated. Both DW224a and DW224aa exhibited

  17. Structure of asymmetrical peptide dendrimers

    NARCIS (Netherlands)

    Okrugin, B.M.; Neelov, I.M.; Leermakers, F.A.M.; Borisov, Oleg V.

    2017-01-01

    Structural properties of asymmetric peptide dendrimers up to the 11th generation are studied on the basis of the self-consistent field Scheutjens-Fleer numerical approach. It is demonstrated that large scale properties such as, e.g., the gyration radius, are relatively weakly affected by the

  18. Peptide-functionalized polyphenylene dendrimers

    NARCIS (Netherlands)

    Herrmann, Andreas; Mihov, Gueorgui; Vandermeulen, Guido W.M.; Klok, Harm-Anton; Müllen, Klaus

    2003-01-01

    This contribution describes the synthesis of polyphenylene dendrimers that are functionalized with up to 16 lysine residues or substituted with short peptide sequences composed of 5 lysine or glutamic acid repeats and a C- or N-terminal cysteine residue. Polyphenylene dendrimers were prepared via a

  19. Synthetic Procedures for Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  20. Double-Stranded Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2001-01-01

    A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. Identification of multifunctional peptides from human milk.

    Science.gov (United States)

    Mandal, Santi M; Bharti, Rashmi; Porto, William F; Gauri, Samiran S; Mandal, Mahitosh; Franco, Octavio L; Ghosh, Ananta K

    2014-06-01

    Pharmaceutical industries have renewed interest in screening multifunctional bioactive peptides as a marketable product in health care applications. In this context, several animal and plant peptides with potential bioactivity have been reported. Milk proteins and peptides have received much attention as a source of health-enhancing components to be incorporated into nutraceuticals and functional foods. By using this source, 24 peptides have been fractionated and purified from human milk using RP-HPLC. Multifunctional roles including antimicrobial, antioxidant and growth stimulating activity have been evaluated in all 24 fractions. Nevertheless, only four fractions show multiple combined activities among them. Using a proteomic approach, two of these four peptides have been identified as lactoferrin derived peptide and kappa casein short chain peptide. Lactoferrin derived peptide (f8) is arginine-rich and kappa casein derived (f12) peptide is proline-rich. Both peptides (f8 and f12) showed antimicrobial activities against both Gram-positive and Gram-negative bacteria. Fraction 8 (f8) exhibits growth stimulating activity in 3T3 cell line and f12 shows higher free radical scavenging activity in comparison to other fractions. Finally, both peptides were in silico evaluated and some insights into their mechanism of action were provided. Thus, results indicate that these identified peptides have multiple biological activities which are valuable for the quick development of the neonate and may be considered as potential biotechnological products for nutraceutical industry. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Characterization of Synthetic Peptides by Mass Spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI...

  3. Peptides and metallic nanoparticles for biomedical applications.

    NARCIS (Netherlands)

    Kogan, M.J.; Olmedo, I.; Hosta, L.; Guerrero, A.R.; Cruz Ricondo, L.J.; Albericio, F.

    2007-01-01

    In this review, we describe the contribution of peptides to the biomedical applications of metallic nanoparticles. We also discuss strategies for the preparation of peptide-nanoparticle conjugates and the synthesis of the peptides and metallic nanoparticles. An overview of the techniques used for

  4. Preparation of arginine-glycine-aspartic acid-modified biopolymeric nanoparticles containing epigalloccatechin-3-gallate for targeting vascular endothelial cells to inhibit corneal neovascularization.

    Science.gov (United States)

    Chang, Che-Yi; Wang, Ming-Chen; Miyagawa, Takuya; Chen, Zhi-Yu; Lin, Feng-Huei; Chen, Ko-Hua; Liu, Guei-Sheung; Tseng, Ching-Li

    2017-01-01

    Neovascularization (NV) of the cornea can disrupt visual function, causing ocular diseases, including blindness. Therefore, treatment of corneal NV has a high public health impact. Epigalloccatechin-3-gallate (EGCG), presenting antiangiogenesis effects, was chosen as an inhibitor to treat human vascular endothelial cells for corneal NV treatment. An arginine-glycine-aspartic acid (RGD) peptide-hyaluronic acid (HA)-conjugated complex coating on the gelatin/EGCG self-assembly nanoparticles (GEH-RGD NPs) was synthesized for targeting the α v β 3 integrin on human umbilical vein endothelial cells (HUVECs) in this study, and a corneal NV mouse model was used to evaluate the therapeutic effect of this nanomedicine used as eyedrops. HA-RGD conjugation via COOH and amine groups was confirmed by 1 H-nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The average diameter of GEH-RGD NPs was 168.87±22.5 nm with positive charge (19.7±2 mV), with an EGCG-loading efficiency up to 95%. Images of GEH-RGD NPs acquired from transmission electron microscopy showed a spherical shape and shell structure of about 200 nm. A slow-release pattern was observed in the nanoformulation at about 30% after 30 hours. Surface plasmon resonance confirmed that GEH-RGD NPs specifically bound to the integrin α v β 3 . In vitro cell-viability assay showed that GEH-RGD efficiently inhibited HUVEC proliferation at low EGCG concentrations (20 μg/mL) when compared with EGCG or non-RGD-modified NPs. Furthermore, GEH-RGD NPs significantly inhibited HUVEC migration down to 58%, lasting for 24 hours. In the corneal NV mouse model, fewer and thinner vessels were observed in the alkali-burned cornea after treatment with GEH-RGD NP eyedrops. Overall, this study indicates that GEH-RGD NPs were successfully developed and synthesized as an inhibitor of vascular endothelial cells with specific targeting capacity. Moreover, they can be used in eyedrops to inhibit angiogenesis in corneal NV

  5. Self-assembled arginine-rich peptides as effective antimicrobial agents.

    Science.gov (United States)

    Mi, Gujie; Shi, Di; Herchek, Whitney; Webster, Thomas J

    2017-04-01

    Bacteria can adapt to their ever-changing environment to develop a resistance to commonly used antibiotics. This escalating evolution of bacteria coupled with a diminished number of effective antibiotics has caused a global healthcare crisis. New antimicrobials and novel approaches to tackle this problem are urgently needed. Antimicrobial peptides are of particular interest in this endeavor due to their broad spectrum antimicrobial properties as well as ability to combat multi-drug resistant bacteria. Most peptides have both hydrophobic and hydrophilic regions that enable them to be soluble in an aqueous solution, yet can insert into and subsequently disintegrate lipid rich membranes through diverse mechanisms. In this study, a novel class of cationic nanoparticles (formed by the self-assembly of an amphiphilic peptide) were shown to have strong antimicrobial properties against gram-positive bacteria, specifically Staphylococcus aureus, Staphylococcus epidermidis, and methicillin-resistant Staphylococcus aureus (MRSA) with minimal toxicity to human dermal fibroblasts. The particular self-assembled structure tested here included an arginine rich nanoparticle (C17 H35 GR7RGDS or amphiphilic peptide nanoparticles, APNPs) which incorporated seven arginine residues (imparting a positive charge to improve membrane interactions), a hydrophobic block which drove the self-assembly process, and the presence of an amino acid quadruplet arginine-glycine-aspartic acid-serine (RGDS) which may render these nanoparticles capable of attracting healthy cells while competing bacterial adherence to fibronectin, an adhesive protein found on cell surfaces. As such, this in vitro study demonstrated that the presently formulated APNPs should be further studied for a wide range of antibacterial applications where antibiotics are no longer useful. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1046-1054, 2017. © 2017 Wiley Periodicals, Inc.

  6. Design of Decorated Self-Assembling Peptide Hydrogels as Architecture for Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Annj Zamuner

    2016-08-01

    Full Text Available Hydrogels from self-assembling ionic complementary peptides have been receiving a lot of interest from the scientific community as mimetic of the extracellular matrix that can offer three-dimensional supports for cell growth or can become vehicles for the delivery of stem cells, drugs or bioactive proteins. In order to develop a 3D “architecture” for mesenchymal stem cells, we propose the introduction in the hydrogel of conjugates obtained by chemoselective ligation between a ionic-complementary self-assembling peptide (called EAK and three different bioactive molecules: an adhesive sequence with 4 Glycine-Arginine-Glycine-Aspartic Acid-Serine-Proline (GRGDSP motifs per chain, an adhesive peptide mapped on h-Vitronectin and the growth factor Insulin-like Growth Factor-1 (IGF-1. The mesenchymal stem cell adhesion assays showed a significant increase in adhesion and proliferation for the hydrogels decorated with each of the synthesized conjugates; moreover, such functionalized 3D hydrogels support cell spreading and elongation, validating the use of this class of self-assembly peptides-based material as very promising 3D model scaffolds for cell cultures, at variance of the less realistic 2D ones. Furthermore, small amplitude oscillatory shear tests showed that the presence of IGF-1-conjugate did not alter significantly the viscoelastic properties of the hydrogels even though differences were observed in the nanoscale structure of the scaffolds obtained by changing their composition, ranging from long, well-defined fibers for conjugates with adhesion sequences to the compact and dense film for the IGF-1-conjugate.

  7. MEPE-Derived ASARM Peptide Inhibits Odontogenic Differentiation of Dental Pulp Stem Cells and Impairs Mineralization in Tooth Models of X-Linked Hypophosphatemia

    Science.gov (United States)

    Khaddam, Mayssam; Naji, Jiar; Coyac, Benjamin R.; Baroukh, Brigitte; Letourneur, Franck; Lesieur, Julie; Decup, Franck; Le Denmat, Dominique; Nicoletti, Antonino; Poliard, Anne; Rowe, Peter S.; Huet, Eric; Vital, Sibylle Opsahl; Linglart, Agnès; McKee, Marc D.; Chaussain, Catherine

    2013-01-01

    Mutations in PHEX (phosphate-regulating gene with homologies to endopeptidases on the X-chromosome) cause X-linked familial hypophosphatemic rickets (XLH), a disorder having severe bone and tooth dentin mineralization defects. The absence of functional PHEX leads to abnormal accumulation of ASARM (acidic serine- and aspartate-rich motif) peptide − a substrate for PHEX and a strong inhibitor of mineralization − derived from MEPE (matrix extracellular phosphoglycoprotein) and other matrix proteins. MEPE-derived ASARM peptide accumulates in tooth dentin of XLH patients where it may impair dentinogenesis. Here, we investigated the effects of ASARM peptides in vitro and in vivo on odontoblast differentiation and matrix mineralization. Dental pulp stem cells from human exfoliated deciduous teeth (SHEDs) were seeded into a 3D collagen scaffold, and induced towards odontogenic differentiation. Cultures were treated with synthetic ASARM peptides (phosphorylated and nonphosphorylated) derived from the human MEPE sequence. Phosphorylated ASARM peptide inhibited SHED differentiation in vitro, with no mineralized nodule formation, decreased odontoblast marker expression, and upregulated MEPE expression. Phosphorylated ASARM peptide implanted in a rat molar pulp injury model impaired reparative dentin formation and mineralization, with increased MEPE immunohistochemical staining. In conclusion, using complementary models to study tooth dentin defects observed in XLH, we demonstrate that the MEPE-derived ASARM peptide inhibits both odontogenic differentiation and matrix mineralization, while increasing MEPE expression. These results contribute to a partial mechanistic explanation of XLH pathogenesis: direct inhibition of mineralization by ASARM peptide leads to the mineralization defects in XLH teeth. This process appears to be positively reinforced by the increased MEPE expression induced by ASARM. The MEPE-ASARM system can therefore be considered as a potential therapeutic

  8. MEPE-derived ASARM peptide inhibits odontogenic differentiation of dental pulp stem cells and impairs mineralization in tooth models of X-linked hypophosphatemia.

    Science.gov (United States)

    Salmon, Benjamin; Bardet, Claire; Khaddam, Mayssam; Naji, Jiar; Coyac, Benjamin R; Baroukh, Brigitte; Letourneur, Franck; Lesieur, Julie; Decup, Franck; Le Denmat, Dominique; Nicoletti, Antonino; Poliard, Anne; Rowe, Peter S; Huet, Eric; Vital, Sibylle Opsahl; Linglart, Agnès; McKee, Marc D; Chaussain, Catherine

    2013-01-01

    Mutations in PHEX (phosphate-regulating gene with homologies to endopeptidases on the X-chromosome) cause X-linked familial hypophosphatemic rickets (XLH), a disorder having severe bone and tooth dentin mineralization defects. The absence of functional PHEX leads to abnormal accumulation of ASARM (acidic serine- and aspartate-rich motif) peptide - a substrate for PHEX and a strong inhibitor of mineralization - derived from MEPE (matrix extracellular phosphoglycoprotein) and other matrix proteins. MEPE-derived ASARM peptide accumulates in tooth dentin of XLH patients where it may impair dentinogenesis. Here, we investigated the effects of ASARM peptides in vitro and in vivo on odontoblast differentiation and matrix mineralization. Dental pulp stem cells from human exfoliated deciduous teeth (SHEDs) were seeded into a 3D collagen scaffold, and induced towards odontogenic differentiation. Cultures were treated with synthetic ASARM peptides (phosphorylated and nonphosphorylated) derived from the human MEPE sequence. Phosphorylated ASARM peptide inhibited SHED differentiation in vitro, with no mineralized nodule formation, decreased odontoblast marker expression, and upregulated MEPE expression. Phosphorylated ASARM peptide implanted in a rat molar pulp injury model impaired reparative dentin formation and mineralization, with increased MEPE immunohistochemical staining. In conclusion, using complementary models to study tooth dentin defects observed in XLH, we demonstrate that the MEPE-derived ASARM peptide inhibits both odontogenic differentiation and matrix mineralization, while increasing MEPE expression. These results contribute to a partial mechanistic explanation of XLH pathogenesis: direct inhibition of mineralization by ASARM peptide leads to the mineralization defects in XLH teeth. This process appears to be positively reinforced by the increased MEPE expression induced by ASARM. The MEPE-ASARM system can therefore be considered as a potential therapeutic

  9. Insect Peptides - Perspectives in Human Diseases Treatment.

    Science.gov (United States)

    Chowanski, Szymon; Adamski, Zbigniew; Lubawy, Jan; Marciniak, Pawel; Pacholska-Bogalska, Joanna; Slocinska, Malgorzata; Spochacz, Marta; Szymczak, Monika; Urbanski, Arkadiusz; Walkowiak-Nowicka, Karolina; Rosinski, Grzegorz

    2017-01-01

    Insects are the largest and the most widely distributed group of animals in the world. Their diversity is a source of incredible variety of different mechanisms of life processes regulation. There are many agents that regulate immunology, reproduction, growth and development or metabolism. Hence, it seems that insects may be a source of numerous substances useful in human diseases treatment. Especially important in the regulation of insect physiology are peptides, like neuropeptides, peptide hormones or antimicrobial peptides. There are two main aspects where they can be helpful, 1) Peptides isolated from insects may become potential drugs in therapy of different diseases, 2) A lot of insect peptide hormones show structural or functional homology to mammalian peptide hormones and the comparative studies may give a new look on human disorders. In our review we focused on three group of insect derived peptides: 1) immune-active peptides, 2) peptide hormones and 3) peptides present in venoms. In our review we try to show the considerable potential of insect peptides in searching for new solutions for mammalian diseases treatment. We summarise the knowledge about properties of insect peptides against different virulent agents, anti-inflammatory or anti-nociceptive properties as well as compare insect and mammalian/vertebrate peptide endocrine system to indicate usefulness of knowledge about insect peptide hormones in drug design. The field of possible using of insect delivered peptide to therapy of various human diseases is still not sufficiently explored. Undoubtedly, more attention should be paid to insects due to searching new drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. THE EFFECT OF THE HYDROGEN ION CONCENTRATION ON THE RATE OF HYDROLYSIS OF GLYCYL GLYCINE, GLYCYL LEUCINE, GLYCYL ALANINE, GLYCYL ASPARAGINE, GLYCYL ASPARTIC ACID, AND BIURET BASE BY EREPSIN

    Science.gov (United States)

    Northrop, John H.; Simms, Henry S.

    1928-01-01

    1. The rate of hydrolysis at different pH values of glycyl glycine, glycyl leucine, glycyl alanine, glycyl asparagine, glycyl aspartic acid and biuret base has been determined. 2. The pH-activity curves obtained in this way differ for the different substrates. 3. The curves can be satisfactorily predicted by the assumption that erepsin is a weak acid or base with a dissociation constant of 10–7.6 and that the reaction takes place between a particular ionic species of the enzyme and of the substrate. There are several possible arrangements which will predict the experimental results. 4. The rate of inactivation of erepsin at various pH values has been determined and found to agree with the assumption used above, that the enzyme is a weak acid or base with a dissociation constant of about 10–7.6. 5. It is pointed out that if the mechanism assumed is correct, the determination of a significant value for the relative rate of hydrolysis of various peptides is a very uncertain procedure. PMID:19872461

  11. Radiolabeled cyclic arginine-glycine-aspartic (RGD)-conjugated iron oxide nanoparticles as single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) dual-modality agents for imaging of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Shengming; Zhang, Wei; Zhang, Bin, E-mail: zbnuclmd@126.com [The First Affiliated Hospital of Soochow University, Department of Nuclear Medicine (China); Hong, Ruoyu [Soochow University, College of Chemistry, Chemical Engineering and Materials Science & Key Laboratory of Organic Synthesis of Jiangsu Province (China); Chen, Qing; Dong, Jiajia [The First Affiliated Hospital of Soochow University, Department of Nuclear Medicine (China); Chen, Yinyiin [The First Affiliated Hospital of Soochow University, Department of Radiology (China); Chen, Zhiqiang; Wu, Yiwei, E-mail: wuyiwei3988@gmail.com [The First Affiliated Hospital of Soochow University, Department of Nuclear Medicine (China)

    2015-01-15

    Ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) modified with a novel cyclic arginine-glycine-aspartate (RGD) peptide were made and radiolabeled as single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) dual-modality agents for imaging of breast cancer. The probe was tested both in vitro and in vivo to determine its receptor targeting efficacy and feasibility for SPECT and MRI. The radiochemical syntheses of {sup 125}I-cRGD-USPIO were accomplished with a radiochemical purity of 96.05 ± 0.33 %. High radiochemical stability was found in fresh human serum and in phosphate-buffered saline. The average hydrodynamic size of {sup 125}I-cRGD-USPIO determined by dynamic light scattering was 51.3 nm. Results of in vitro experiments verified the specificity of the radiolabeled nanoparticles to tumor cells. Preliminary biodistribution studies of {sup 125}I-radiolabeled cRGD-USPIO in Bcap37-bearing nude mice showed that it had long circulation half-life, high tumor uptake, and high initial blood retention with moderate liver uptake. In vivo tumor targeting and uptake of the radiolabeled nanoparticles in mice model were visualized by SPECT and MRI collected at different time points. Our results strongly indicated that the {sup 125}I-cRGD-USPIO could be used as a promising bifunctional radiotracer for early clinical tumor detection with high sensitivity and high spatial resolution by SPECT and MRI.

  12. Development of an Amperometric Biosensor Platform for the Combined Determination of L-Malic, Fumaric, and L-Aspartic Acid.

    Science.gov (United States)

    Röhlen, Désirée L; Pilas, Johanna; Schöning, Michael J; Selmer, Thorsten

    2017-10-01

    Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD+) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM-1 (L-malate biosensor) and 0.4 μA mM-1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM-1. The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.

  13. Peptides: Production, bioactivity, functionality, and applications

    DEFF Research Database (Denmark)

    Hajfathalian, Mona; Ghelichi, Sakhi; García Moreno, Pedro Jesús

    2017-01-01

    Production of peptides with various effects from proteins of different sources continues to receive academic attention. Researchers of different disciplines are putting increasing efforts to produce bioactive and functional peptides from different sources such as plants, animals, and food industry...... by-products. The aim of this review is to introduce production methods of hydrolysates and peptides and provide a comprehensive overview of their bioactivity in terms of their effects on immune, cardiovascular, nervous, and gastrointestinal systems. Moreover, functional and antioxidant properties...... of hydrolysates and isolated peptides are reviewed. Finally, industrial and commercial applications of bioactive peptides including their use in nutrition and production of pharmaceuticals and nutraceuticals are discussed....

  14. Interpreting peptide mass spectra by VEMS

    DEFF Research Database (Denmark)

    Mathiesen, Rune; Lundsgaard, M.; Welinder, Karen G.

    2003-01-01

    of peptide MS/MS spectra imported in text file format. Peaks are annotated, the monoisotopic peaks retained, and the b-and y-ion series identified in an interactive manner. The called peptide sequence is searched against a local protein database for sequence identity and peptide mass. The report compares...... the calculated and the experimental mass spectrum of the called peptide. The program package includes four accessory programs. VEMStrans creates protein databases in FASTA format from EST or cDNA sequence files. VEMSdata creates a virtual peptide database from FASTA files. VEMSdist displays the distribution...

  15. Developments in peptide and amide synthesis.

    Science.gov (United States)

    Albericio, Fernando

    2004-06-01

    The solid-phase methodology is key for an effective synthesis of peptides, from a milligram scale for research to a multi-kilo scale for drug production. Indeed, small peptides containing up to 20-30 amino acids are most readily synthesized by a solid-phase strategy. Larger peptides (up to 60 amino acids) should be synthesized by a convergent approach (i.e. synthesis of protected constituent peptides in solid-phase and combination of these units in solution). Larger peptides and proteins are prepared by chemical ligation, where unprotected segments have been prepared in solid-phase.

  16. Possible modulation of process extension by N-methyl-D-aspartate receptor expressed in osteocytic MLO-Y4 cells.

    Science.gov (United States)

    Fujita, Hiroyuki; Hinoi, Eiichi; Nakatani, Eri; Yamamoto, Tomomi; Takarada, Takeshi; Yoneda, Yukio

    2012-01-01

    In contrast to osteoblasts, little attention has been paid to expression profiles of different glutamatergic signaling machineries in osteocytes, which are the most abundant cells with a possible role as a mechanical sensor in bone. Here, we show that N-methyl-D-aspartate receptor (NMDAR) is expressed by osteocytic cells in five-weeks-old mouse tibiae in vivo as well as by osteocytic MLO-Y4 cells in vitro. Sustained exposure to the NMDAR antagonist dizocilpine significantly increased the number of cells with processes in cultured MLO-Y4 cells. These results suggest that NMDAR would be expressed by osteocytes with an unidentified role in the process extension.

  17. Towards the MHC-peptide combinatorics.

    Science.gov (United States)

    Kangueane, P; Sakharkar, M K; Kolatkar, P R; Ren, E C

    2001-05-01

    The exponentially increased sequence information on major histocompatibility complex (MHC) alleles points to the existence of a high degree of polymorphism within them. To understand the functional consequences of MHC alleles, 36 nonredundant MHC-peptide complexes in the protein data bank (PDB) were examined. Induced fit molecular recognition patterns such as those in MHC-peptide complexes are governed by numerous rules. The 36 complexes were clustered into 19 subgroups based on allele specificity and peptide length. The subgroups were further analyzed for identifying common features in MHC-peptide binding pattern. The four major observations made during the investigation were: (1) the positional preference of peptide residues defined by percentage burial upon complex formation is shown for all the 19 subgroups and the burial profiles within entries in a given subgroup are found to be similar; (2) in class I specific 8- and 9-mer peptides, the fourth residue is consistently solvent exposed, however this observation is not consistent in class I specific 10-mer peptides; (3) an anchor-shift in positional preference is observed towards the C terminal as the peptide length increases in class II specific peptides; and (4) peptide backbone atoms are proportionately dominant at the MHC-peptide interface.

  18. Dietary lipids and sweeteners regulate glucagon-like peptide-2 secretion.

    Science.gov (United States)

    Sato, Shingo; Hokari, Ryota; Kurihara, Chie; Sato, Hirokazu; Narimatsu, Kazuyuki; Hozumi, Hideaki; Ueda, Toshihide; Higashiyama, Masaaki; Okada, Yoshikiyo; Watanabe, Chikako; Komoto, Shunsuke; Tomita, Kengo; Kawaguchi, Atsushi; Nagao, Shigeaki; Miura, Soichiro

    2013-04-15

    Glucagon-like peptide-2 (GLP-2) is a potent intestinal growth factor derived from enteroendocrine L cells. Although food intake is known to increase GLP-2 secretion, its regulatory mechanisms are largely unknown as a result of its very short half-life in venules. The aims of this study were to compare the effects of luminal nutrients on the stimulation of GLP-2 secretion in vivo using lymph samples and to clarify the involvement of the sweet taste receptor in this process in vitro. Lymph samples were collected from the thoracic duct after bolus administration of dietary lipids or sweetening agents into the duodenum of rats. Human enteroendocrine NCI-H716 cells were also used to compare the effects of various nutrients on GLP-2 secretion. GLP-2 concentrations were measured by ELISA in vivo and in vitro. GLP-2 secretion was enhanced by polyunsaturated fatty acid- and monounsaturated fatty acid-rich dietary oils, dietary carbohydrates, and some kinds of sweeteners in rats; this effect was reproduced in NCI-H716 cells using α-linolenic acid (αLA), glucose, and sweeteners. GLP-2 secretion induced by sweetening agents was inhibited by lactisole, a sweetness-antagonizing inhibitor of T1R3. In contrast, lactisole was unable to inhibit GLP-2 secretion induced by αLA alone. Our results suggested that fatty acid- and sweetener-induced GLP-2 secretion may be mediated by two different pathways, with the sweet taste receptor involved in the regulation of the latter.

  19. Arginine-glycine-aspartic acid modified rosette nanotube-hydrogel composites for bone tissue engineering.

    Science.gov (United States)

    Zhang, Lijie; Rakotondradany, Felaniaina; Myles, Andrew J; Fenniri, Hicham; Webster, Thomas J

    2009-03-01

    An RGDSK (Arg-Gly-Asp-Ser-Lys) modified rosette nanotube (RNT) hydrogel composite with unique surface chemistry and favorable cytocompatibility properties for bone repair was developed and investigated. The RNTs are biologically inspired nanomaterials obtained through the self-assembly of a DNA base analog (G wedge C base) with tailorable chemical functionality and physical properties. In this study, a cell-adhesive RGDSK peptide was covalently attached to the G wedge C base, assembled into RNTs, and structurally characterized by (1)H/(13)C NMR spectroscopy, mass spectrometry, and electron microscopy. Importantly, results showed that the RGDSK modified RNT hydrogels caused around a 200% increase in osteoblast (bone-forming cell) adhesion relative to hydrogel controls. In addition, osteoblast proliferation was enhanced on RNT hydrogels compared to hydrogel controls after 3 days, which further confirmed the promising cytocompatibility properties of this scaffold. When analyzing the mechanism of increased osteoblast density on RNT hydrogels, it was found that more fibronectin (a protein which promotes osteoblast adhesion) adsorption occurred on RNT coated hydrogels than uncoated hydrogels. As osteoblast adhesion was greatly enhanced on RNT coated hydrogels compared to poly l-lysine and collagen coated hydrogels, this study indicated that not only the surface chemistry was important in improving osteoblast density (via lysine or RGD groups functionalized on RNTs), but also the biomimetic nanoscale properties of RNTs provided a cell-favorable environment. These results warrant further studies on RNTs in hydrogels for better bone tissue regeneration.

  20. Taylor Dispersion Analysis as a promising tool for assessment of peptide-peptide interactions

    DEFF Research Database (Denmark)

    Høgstedt, Ulrich B; Schwach, Grégoire; van de Weert, Marco

    2016-01-01

    . In this work, we show that protein-protein and peptide-peptide interactions can advantageously be investigated by measurement of the diffusion coefficient using Taylor Dispersion Analysis. Through comparison to Dynamic Light Scattering it was shown that Taylor Dispersion Analysis is well suited...... for the characterization of protein-protein interactions of solutions of α-lactalbumin and human serum albumin. The peptide-peptide interactions of three selected peptides were then investigated in a concentration range spanning from 0.5mg/ml up to 80mg/ml using Taylor Dispersion Analysis. The peptide-peptide interactions...... determination indicated that multibody interactions significantly affect the PPIs at concentration levels above 25mg/ml for the two charged peptides. Relative viscosity measurements, performed using the capillary based setup applied for Taylor Dispersion Analysis, showed that the viscosity of the peptide...