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Sample records for peptide analogues reveal

  1. Naturally Inspired Peptide Leads: Alanine Scanning Reveals an Actin-Targeting Thiazole Analogue of Bisebromoamide.

    Science.gov (United States)

    Johnston, Heather J; Boys, Sarah K; Makda, Ashraff; Carragher, Neil O; Hulme, Alison N

    2016-09-02

    Systematic alanine scanning of the linear peptide bisebromoamide (BBA), isolated from a marine cyanobacterium, was enabled by solid-phase peptide synthesis of thiazole analogues. The analogues have comparable cytotoxicity (nanomolar) to that of BBA, and cellular morphology assays indicated that they target the actin cytoskeleton. Pathway inhibition in human colon tumour (HCT116) cells was explored by reverse phase protein array (RPPA) analysis, which showed a dose-dependent response in IRS-1 expression. Alanine scanning reveals a structural dependence to the cytotoxicity, actin targeting and pathway inhibition, and allows a new readily synthesised lead to be proposed. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  2. Revealing Television's Analogue Heroes

    Directory of Open Access Journals (Sweden)

    Vanessa Jackson

    2013-12-01

    Full Text Available In this article I will argue that we need to create new archival models in order to preserve and share knowledge of historical, ‘hidden’ television professions and production cultures. Oral history traditions of recording life stories give us a useful starting point. Engineering ‘encounters’ between skilled television technicians, and the now obsolete equipment they operated in the 1970s and 80s, is challenging for a myriad of reasons, but videoing the interaction of man and machine provides us with a rich insight into how analogue television was produced and broadcast. Social media enables us to disseminate these histories in new and innovative ways..

  3. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues.

    NARCIS (Netherlands)

    Rolleman, E.J.; Melis, M.; Valkema, R.; Boerman, O.C.; Krenning, E.P.; Jong, M. de

    2010-01-01

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides

  4. Transdermal delivery of a melanotropic peptide hormone analogue

    International Nuclear Information System (INIS)

    Dawson, B.V.; Hadley, M.E.; Kreutzfeld, K.; Dorr, R.T.; Hruby, V.J.; Al-Obeidi, F.; Don, S.

    1988-01-01

    We previously reported that topical application of [Nl3 4 ,D-Phe 7 ]alpha-MSH, a superpotent analogue of alpha-melanocyte stimulating hormone, to mice induces a darkening of follicular melanocytes throughout the skin. We now report that the melanotropin analogue can be delivered across mouse but not rat skin in an in vitro model system. Passage of the analogue from the topically applied vehicle (polyethylene glycol) across the skin into a subcutaneous receiving vessel was demonstrated by both bioassay as well as by radioimmunoassay. The bioassay data demonstrate that percutaneous absorption of the melanotropin did not result in loss of biological activity of the peptide. The differential penetration of the peptide across rodent skin reveals that one cannot predict percutaneous absorption of a substance across the stratum corneum from studies on a single species. The present results are the first to demonstrate, by direct quantitative measurements, that a bioactive peptide can be delivered across the vertebrate integument in vitro. These studies point out the potential of a topically applied melanotropin for tanning of the skin and possibly for treatment of certain hypopigmentary disorders

  5. Glucagon-like peptide-1 analogues: An overview

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    Vishal Gupta

    2013-01-01

    Full Text Available Abnormalities of the incretin axis have been implicated in the pathogenesis of type 2 diabetes mellitus. Glucagon-like peptide-1 (GLP-1 and gastroinhibitory intestinal peptide constitutes >90% of all the incretin function. Augmentation of GLP-1 results in improvement of beta cell health in a glucose-dependant manner (post-prandial hyperglycemia and suppression of glucagon (fasting hyperglycemia, amongst other beneficial pleiotropic effects. Native GLP-1 has a very short plasma half-life and novel methods have been developed to augment its half life, such that its anti-hyperglycemic effects can be exploited. They can be broadly classified as exendin-based therapies (exenatide, exenatide once weekly, DPP-4-resistant analogues (lixisenatide, albiglutide, and analogues of human GLP-1 (liraglutide, taspoglutide. Currently, commercially available analogues are exenatide, exenatide once weekly, and liraglutide. This review aims to provide an overview of most GLP-1 analogues.

  6. Ribosome-catalyzed formation of an abnormal peptide analogue

    International Nuclear Information System (INIS)

    Roesser, J.R.; Chorghade, M.S.; Hecht, S.M.

    1986-01-01

    The peptidyl-tRNA analogue N-(chloracetyl) phenylalanyl-tRNA/sup Phe/ was prepared by chemical aminoacylation and prebound to the P site of Escherichia coli ribosomes in response to poly(uridylic acid). Admixture of phenylalanyl-tRNA/sup Phe/ to the A site resulted in the formation of two dipeptides, one of which was found by displacement of chloride ion from the peptidyl-tRNA. This constitutes the first example of ribosome-mediated formation of a peptide of altered connectivity and suggests a need for revision of the current model of peptide bond formation. Also suggested by the present finding is the feasibility of utilizing tRNAs to prepare polypeptides of altered connectivity in an in vitro protein biosynthesizing system. [ 32 P]-oligo(rA), [ 3 H]- and [ 14 C] phenylalanines were used in the assay of the peptidye-tRNA analogue

  7. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, V 220, Rotterdam (Netherlands); Boerman, Otto C. [Radboud University Hospital, Department of Nuclear Medicine, Nijmegen (Netherlands)

    2010-05-15

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  8. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    International Nuclear Information System (INIS)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de; Boerman, Otto C.

    2010-01-01

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  9. Synthesis and antioxidant activity of peptide-based ebselen analogues.

    Science.gov (United States)

    Satheeshkumar, Kandhan; Mugesh, Govindasamy

    2011-04-18

    A series of di- and tripeptide-based ebselen analogues has been synthesized. The compounds were characterized by (1)H, (13)C, and (77)Se NMR spectroscopy and mass spectral techniques. The glutathione peroxidase (GPx)-like antioxidant activity has been studied by using H(2)O(2) , tert-butyl hydroperoxide (tBuOOH), and cumene hydroperoxide (Cum-OOH) as substrates, and glutathione (GSH) as a cosubstrate. Although all the peptide-based compounds have a selenazole ring similar to that of ebselen, the GPx activity of these compounds highly depends on the nature of the peptide moiety attached to the nitrogen atom of the selenazole ring. It was observed that the introduction of a phenylalanine (Phe) amino acid residue in the N-terminal reduces the activity in all three peroxide systems. On the other hand, the introduction of aliphatic amino acid residues such as valine (Val) significantly enhances the GPx activity of the ebselen analogues. The difference in the catalytic activity of dipeptide-based ebselen derivatives can be ascribed mainly to the change in the reactivity of these compounds toward GSH and peroxide. Although the presence of the Val-Ala-CO(2) Me moiety facilitates the formation of a catalytically active selenol species, the reaction of ebselen analogues that has a Phe-Ile-CO(2) Me residue with GSH does not generate the corresponding selenol. To understand the antioxidant activity of the peptide-based ebselen analogues in the absence of GSH, these compounds were studied for their ability to inhibit peroxynitrite (PN)-mediated nitration of bovine serum albumin (BSA) and oxidation of dihydrorhodamine 123. In contrast to the GPx activity, the PN-scavenging activity of the Phe-based peptide analogues was found to be comparable to that of the Val-based compounds. However, the introduction of an additional Phe residue to the ebselen analogue that had a Val-Ala dipeptide significantly reduced the potency of the parent compound in PN-mediated nitration. Copyright

  10. Rapid Analysis of Protein Farnesyltransferase Substrate Specificity Using Peptide Libraries and Isoprenoid Diphosphate Analogues

    OpenAIRE

    Wang, Yen-Chih; Dozier, Jonathan K.; Beese, Lorena S.; Distefano, Mark D.

    2014-01-01

    Protein farnesytransferase (PFTase) catalyzes the farnesylation of proteins with a carboxy-terminal tetrapeptide sequence denoted as a Ca1a2X box. To explore the specificity of this enzyme, an important therapeutic target, solid-phase peptide synthesis in concert with a peptide inversion strategy was used to prepare two libraries, each containing 380 peptides. The libraries were screened using an alkyne-containing isoprenoid analogue followed by click chemistry with biotin azide and subsequen...

  11. Novel DOTA-based prochelator for divalent peptide vectorization: synthesis of dimeric bombesin analogues for multimodality tumor imaging and therapy.

    Science.gov (United States)

    Abiraj, Keelara; Jaccard, Hugues; Kretzschmar, Martin; Helm, Lothar; Maecke, Helmut R

    2008-07-28

    Dimeric peptidic vectors, obtained by the divalent grafting of bombesin analogues on a newly synthesized DOTA-based prochelator, showed improved qualities as tumor targeted imaging probes in comparison to their monomeric analogues.

  12. Biological effects of a de novo designed myxoma virus peptide analogue: evaluation of cytotoxicity on tumor cells.

    Directory of Open Access Journals (Sweden)

    Taghrid S Istivan

    Full Text Available BACKGROUND: The Resonant Recognition Model (RRM is a physico-mathematical model that interprets protein sequence linear information using digital signal processing methods. In this study the RRM concept was employed for structure-function analysis of myxoma virus (MV proteins and the design of a short bioactive therapeutic peptide with MV-like antitumor/cytotoxic activity. METHODOLOGY/PRINCIPAL FINDINGS: The analogue RRM-MV was designed by RRM as a linear 18 aa 2.3 kDa peptide. The biological activity of this computationally designed peptide analogue against cancer and normal cell lines was investigated. The cellular cytotoxicity effects were confirmed by confocal immunofluorescence microscopy, by measuring the levels of cytoplasmic lactate dehydrogenase (LDH and by Prestoblue cell viability assay for up to 72 hours in peptide treated and non-treated cell cultures. Our results revealed that RRM-MV induced a significant dose and time-dependent cytotoxic effect on murine and human cancer cell lines. Yet, when normal murine cell lines were similarly treated with RRM-MV, no cytotoxic effects were observed. Furthermore, the non-bioactive RRM designed peptide RRM-C produced negligible cytotoxic effects on these cancer and normal cell lines when used at similar concentrations. The presence/absence of phosphorylated Akt activity in B16F0 mouse melanoma cells was assessed to indicate the possible apoptosis signalling pathway that could be affected by the peptide treatment. So far, Akt activity did not seem to be significantly affected by RRM-MV as is the case for the original viral protein. CONCLUSIONS/SIGNIFICANCE: Our findings indicate the successful application of the RRM concept to design a bioactive peptide analogue (RRM-MV with cytotoxic effects on tumor cells only. This 2.345 kDa peptide analogue to a 49 kDa viral protein may be suitable to be developed as a potential cancer therapeutic. These results also open a new direction to the rational

  13. Stabilization of neurotensin analogues: effect on peptide catabolism, biodistribution and tumor binding

    Energy Technology Data Exchange (ETDEWEB)

    Bruehlmeier, Matthias E-mail: peter.blaeuenstein@psi.ch; Garayoa, Elisa Garcia; Blanc, Alain; Holzer, Barbara; Gergely, Suzanne; Tourwe, Dirk; Schubiger, Pius August; Blaeuenstein, Peter

    2002-04-01

    Neurotensin (NT) receptors in pancreatic and other neuroendocrine tumors are promising targets for imaging and therapeutic purposes. Here, we report on the effect of distinct changes in the peptide chain on catabolism in vitro for five radiolabeled [{sup 99m}Tc] neurotensin analogues having high affinity for neurotensin receptors. Substitution of NT(1-7) by (N{alpha}His)Ac--the Tc-binding moiety--combined with a reduced bond 8-9 (CH{sub 2}NH), N-methylation of peptide bonds or replacement of Ile(12) by tertiary leucin (Tle) led to peptide stabilization of various degrees. Biodistribution studies in nude mice bearing HT29 xenografts showed higher tumor uptake with more stable peptides, yielding high tumor to blood ratios of up to 70.

  14. Design, Recombinant Fusion Expression and Biological Evaluation of Vasoactive Intestinal Peptide Analogue as Novel Antimicrobial Agent

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    Chunlan Xu

    2017-11-01

    Full Text Available Antimicrobial peptides represent an emerging category of therapeutic agents with remarkable structural and functional diversity. Modified vasoactive intestinal peptide (VIP (VIP analogue 8 with amino acid sequence “FTANYTRLRRQLAVRRYLAAILGRR” without haemolytic activity and cytotoxicity displayed enhanced antimicrobial activities against Staphylococcus aureus (S. aureus ATCC 25923 and Escherichia coli (E. coli ATCC 25922 than parent VIP even in the presence of 180 mM NaCl or 50 mM MgCl2, or in the range of pH 4–10. VIP analogue 8 was expressed as fusion protein thioredoxin (Trx-VIP8 in E. coli BL21(DE at a yield of 45.67 mg/L. The minimum inhibitory concentration (MIC of the recombinant VIP analogue 8 against S. aureus ATCC 25923 and E. coli ATCC 25922 were 2 μM. These findings suggest that VIP analogue 8 is a promising candidate for application as a new and safe antimicrobial agent.

  15. An assessment tumor targeting ability of 177Lu labeled cyclic CCK analogue peptide by binding with cholecystokinin receptor

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    Eun-Ha Cho

    2016-07-01

    Full Text Available The cholecystokinin (CCK receptor is known as a receptor that is overexpressed in many human tumors. The present study was designed to investigate the targeting ability of cyclic CCK analogue in AR42J pancreatic cells. The CCK analogues, DOTA-K(glucose-Gly-Trp-Nle-Asp-Phe (DOTA-glucose-CCK and DOTA-Nle-cyclo(Glu-Trp-Nle-Asp-Phe-Lys-NH2 (DOTA-[Nle]-cCCK, were synthesized and radiolabeled with 177Lu, and competitive binding was evaluated. The binding appearance of synthesized peptide with AR42J cells was evaluated by confocal microscopy. And bio-distribution was performed in AR42J xenografted mice. Synthesized peptides were prepared by a solid phase synthesis method, and their purity was over 98%. DOTA is the chelating agent for 177Lu-labeling, in which the peptides were radiolabeled with 177Lu by a high radiolabeling yield. A competitive displacement of 125I-CCK8 on the AR42J cells revealed that the 50% inhibitory concentration value (IC50 was 12.3 nM of DOTA-glucose-CCK and 1.7 nM of DOTA-[Nle]-cCCK. Radio-labeled peptides were accumulated in AR42J tumor in vivo, and %ID/g of the tumor was 0.4 and 0.9 at 2 h p.i. It was concluded that 177Lu-DOTA-[Nle]-cCCK has higher binding affinity than 177Lu-DOTA-glucose-CCK and can be a potential candidate as a targeting modality for a CCK receptor over-expressing tumors.

  16. New insights on mu/delta selectivity of opioid peptides: conformational analysis of deltorphin analogues.

    Science.gov (United States)

    Tancredi, T; Temussi, P A; Picone, D; Amodeo, P; Tomatis, R; Salvadori, S; Marastoni, M; Santagada, V; Balboni, G

    1991-05-01

    The message domain of dermorphin (Tyr-D-Ala-Phe), a natural mu-opioid heptapeptide, has long been considered the main cause of the high mu selectivity of this peptide and of its analogues. The recent discovery, in the skin of Phyllomedusa sauvagei (i.e., the same natural source of dermorphin) and of Phyllomedusa bicolor of deltorphins, challenges this belief. Deltorphins, in fact, are three heptapeptides characterized by a message domain typical of mu-selective peptides, but endowed of an extremely high delta selectivity, the highest of all natural opioid peptides. A conformational analysis of dermorphin and deltorphins, based on nmr studies in DMSO and cryoprotective mixtures and internal energy calculations, showed that the enormous differences in receptor selectivity can be interpreted on the basis of receptor models for mu and delta opioids that recognize the same beta-turn in the N-terminal part, but discriminate for the conformation and polarity of the C-terminal part. Here we present the synthesis, biological activity, and conformational analysis in solution of three deltorphin analogues with very similar constitution, but with different net charge, different location of negative residues, or even without negative residues, which confirm these hypotheses and show that His4 can play a specific structural role.

  17. Technetium-99m somatostatin analogues: effect of labelling methods and peptide sequence

    International Nuclear Information System (INIS)

    Decristoforo, C.; Mather, S.J.

    1999-01-01

    In this paper the preclinical evaluation of the somatostatin analogue RC160 labelled with technetium-99m using bifunctional chelators (BFCs) based on the hydrazinonicotinamide (HYNIC) and N 3 S system is described and a comparison made with [Tyr 3 ]-octreotide (TOC). Conjugates of both peptides with HYNIC, and of RC160 with benzoyl-MAG 3 and an N 3 S-adipate derivative were prepared and radiolabelling performed at high specific activities using tricine, tricine/nicotinic acid and ethylenediamine-N,N'-diacetic adic (EDDA) as co-ligands for HYNIC conjugates. All conjugates and 99m Tc-labelled peptides showed preserved binding affinity for the somatostatin receptor (IC50, Kd 99m Tc-RC160 derivatives compared with 99m Tc-EDDA/HYNIC-[Tyr 3 ]-octreotide (0.2%-3.5%ID/g vs 9.7%ID/g) and correlated well with the reduced internalisation rate for RC160 derivatives. Our results show that the selection of the labelling approach as well as the right choice of the peptide structure are crucial for labelling peptides with 99m Tc to achieve complexes with favourable biodistribution. Despite the relatively low tumour uptake compared with 99m Tc-EDDA/HYNIC-[Tyr 3 ]-octreotide, 99m Tc-RC160 could play a role in imaging tumours that do not bind octreotide derivatives. (orig.)

  18. Synthesis of fluorescent analogues of relaxin family peptides and their preliminary in vitro and in vivo characterization

    Directory of Open Access Journals (Sweden)

    Linda eChan

    2013-12-01

    Full Text Available Relaxin, a heterodimeric polypeptide hormone, is a key regulator of collagen metabolism and multiple vascular control pathways in humans and rodents. Its actions are mediated via its cognate G-protein-coupled receptor, RXFP1 although it also ‘pharmacologically’ activates RXFP2, the receptor for the related, insulin-like peptide 3 (INSL3, which has specific actions on reproduction and bone metabolism. Therefore, experimental tools to facilitate insights into the distinct biological actions of relaxin and INSL3 are required, particularly for studies of tissues containing both RXFP1 and RXFP2. Here, we chemically functionalized human (H2 relaxin, the RXFP1-selective relaxin analogue H2:A(4-24(F23A, and INSL3 to accommodate a fluorophore without marked reduction in binding or activation propensity. Chemical synthesis of the two chains for each peptide was followed by sequential regioselective formation of their three disulfide bonds. Click chemistry conjugation of Cy5.5 at the B-chain N-terminus, with conservation of the disulfide bonds, yielded the analogues displaying appropriate selective binding affinity and ability to activate RXFP1 and/or RXFP2 in vitro. The in vivo biological activity of Cy5.5-H2 relaxin and Cy5.5-H2:A(4-24(F23A was confirmed in mice, as acute icv infusion of these peptides (but not Cy5.5-INSL3 stimulated water drinking, an established behavioral response elicited by central RXFP1 activation. The central distribution of Cy5.5-conjugated peptides was examined in mice killed 30 min after infusion, revealing fluorescence within brain tissue near-adjacent to the cerebral ventricle walls relative to deeper brain areas. These data will aid the interpretation of behavioral studies. Production of fluorophore-conjugated relaxin family peptides will facilitate future pharmacological studies to probe the function of H2 relaxin/RXFP1 and INSL3/RXFP2 signaling in vivo while tracking their distribution following central or peripheral

  19. Structural and functional characterization of a multifunctional alanine-rich peptide analogue from Pleuronectes americanus.

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    Ludovico Migliolo

    Full Text Available Recently, defense peptides that are able to act against several targets have been characterized. The present work focuses on structural and functional evaluation of the peptide analogue Pa-MAP, previously isolated as an antifreeze peptide from Pleuronectes americanus. Pa-MAP showed activities against different targets such as tumoral cells in culture (CACO-2, MCF-7 and HCT-116, bacteria (Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 25923, viruses (HSV-1 and HSV-2 and fungi (Candida parapsilosis ATCC 22019, Trichophyton mentagrophytes (28d&E and T. rubrum (327. This peptide did not show toxicity against mammalian cells such as erythrocytes, Vero and RAW 264.7 cells. Molecular mechanism of action was related to hydrophobic residues, since only the terminal amino group is charged at pH 7 as confirmed by potentiometric titration. In order to shed some light on its structure-function relations, in vitro and in silico assays were carried out using circular dichroism and molecular dynamics. Furthermore, Pa-MAP showed partial unfolding of the peptide changes in a wide pH (3 to 11 and temperature (25 to 95°C ranges, although it might not reach complete unfolding at 95°C, suggesting a high conformational stability. This peptide also showed a conformational transition with a partial α-helical fold in water and a full α-helical core in SDS and TFE environments. These results were corroborated by spectral data measured at 222 nm and by 50 ns dynamic simulation. In conclusion, data reported here show that Pa-MAP is a potential candidate for drug design against pathogenic microorganisms due to its structural stability and wide activity against a range of targets.

  20. Analogues of the Frog-skin Antimicrobial Peptide Temporin 1Tb Exhibit a Wider Spectrum of Activity and a Stronger Antibiofilm Potential as Compared to the Parental Peptide

    Science.gov (United States)

    Grassi, Lucia; Maisetta, Giuseppantonio; Maccari, Giuseppe; Esin, Semih; Batoni, Giovanna

    2017-04-01

    The frog skin-derived peptide Temporin 1Tb (TB) has gained increasing attention as novel antimicrobial agent for the treatment of antibiotic-resistant and/or biofilm-mediated infections. Nevertheless, such a peptide possesses a preferential spectrum of action against Gram-positive bacteria. In order to improve the therapeutic potential of TB, the present study evaluated the antibacterial and antibiofilm activities of two TB analogues against medically relevant bacterial species. Of the two analogues, TB_KKG6A has been previously described in the literature, while TB_L1FK is a new analogue designed by us through statistical-based computational strategies. Both TB analogues displayed a faster and stronger bactericidal activity than the parental peptide, especially against Gram-negative bacteria in planktonic form. Differently from the parental peptide, TB_KKG6A and TB_L1FK were able to inhibit the formation of Staphylococcus aureus biofilms by more than 50% at 12 μM, while only TB_KKG6A prevented the formation of Pseudomonas aeruginosa biofilms at 24 μM. A marked antibiofilm activity against preformed biofilms of both bacterial species was observed for the two TB analogues when used in combination with EDTA. Analysis of synergism at the cellular level suggested that the antibiofilm activity exerted by the peptide-EDTA combinations against mature biofilms might be due mainly to a disaggregating effect on the extracellular matrix in the case of S. aureus, and to a direct activity on biofilm-embedded cells in the case of P. aeruginosa. Both analogues displayed a low hemolytic effect at the active concentrations and, overall, TB_L1FK resulted less cytotoxic towards mammalian cells. Collectively, the results obtained demonstrated that subtle changes in the primary sequence of TB may provide TB analogues that, used alone or in combination with adjuvant molecules such as EDTA, exhibit promising features against both planktonic and biofilm cells of medically relevant

  1. Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity.

    Science.gov (United States)

    Haskell-Luevano, C; Sawyer, T K; Hendrata, S; North, C; Panahinia, L; Stum, M; Staples, D J; Castrucci, A M; Hadley, M F; Hruby, V J

    1996-01-01

    Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity: PEPTIDES 17(6) 995-1002, 1996.-Systematic analysis of fragment derivatives of the superpotent alpha-MSH analogue. Ac-Ser.Tyr-Ser-Nle4-Glu- His-DPhe7-Arg-Trp-Gly-Lys-Pro-Val-NH2(NDP-MSH), led to the discovery of tripeptide agonists possessing prolonged bioactivity in the frog skin assay. Of particular significance to this discovery was Ac-DPhe-Arg-DTrp-NH2, which was the most potent tripeptide in this series exhibiting sustained melanotropic activity. Different pharmacophore models appear to exist that are dependent on the substructure and stereochemistry of the MSH(6-9) "active site." The tripeptides Ac-DPhe-Arg-Trp-NH2, Ac-DPhe-Arg-DTrp-NH2, and Ac-DPhe-DArg-Trp-NH2 stereo-chemical combinations require only Phe7-Xaa8-Trp9, whereas Ac-DPhe-DArg-DTrp-NH2, Ac-Phe-Arg-DTrp-NH2, and Ac-Phe-Arg-Trp-NH2 additionally require His4 for minimal biological activity. Ac-DPhe-Arg-DTrp-NH2 represents a novel prototype lead for the development of MSH-based peptidomimetic agonists.

  2. Summarization on the synthesis and radionuclide-labeling of peptide nucleic acid for an oligonucleotide analogue

    International Nuclear Information System (INIS)

    Song, Hongtao; Zhang, Huaming; Gao, Hui

    2009-04-01

    Peptide nucleic acid (PNA), which is one kind of antisense nucleic acid compounds and an oligonucleotide analogue that binds strongly to DNA and RNA in a sequence specific manner, has its unique advantages in the field of molecular diagnostics and treatment of diseases. Now, people gradually attach more importance to PNA. To optimize the application of PNA in genetic re- search and therapy, a great number of backbone modifications on the newly- type structures of PNA were synthesized to improve its physicochemical proper- ties, such as hybridization speciality, solubility in biofluid, or cell permeability. The modified PNA labeled with radionuclides, which can obtain the aim at specific target and minimal non-target trauma, has important role in research and application of tumorous genitherapy. Here a review on the basic synthesis idea and several primary synthetic methods of PNA analogs was given, and also correlative studies and expectation on the compounds belonging to PNA series labeled with radionuclides were included. (authors)

  3. Novel α-MSH peptide analogues with broad spectrum antimicrobial activity.

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    Paolo Grieco

    Full Text Available Previous investigations indicate that α-melanocyte-stimulating hormone (α-MSH and certain synthetic analogues of it exert antimicrobial effects against bacteria and yeasts. However, these molecules have weak activity in standard microbiology conditions and this hampers a realistic clinical use. The aim in the present study was to identify novel peptides with broad-spectrum antimicrobial activity in growth medium. To this purpose, the Gly10 residue in the [DNal(2'-7, Phe-12]-MSH(6-13 sequence was replaced with conventional and unconventional amino acids with different degrees of conformational rigidity. Two derivatives in which Gly10 was replaced by the residues Aic and Cha, respectively, had substantial activity against Candida strains, including C. albicans, C. glabrata, and C. krusei and against gram-positive and gram-negative bacteria. Conformational analysis indicated that the helical structure along residues 8-13 is a key factor in antimicrobial activity. Synthetic analogues of α-MSH can be valuable agents to treat infections in humans. The structural preferences associated with antimicrobial activity identified in this research can help further development of synthetic melanocortins with enhanced biological activity.

  4. Natural and Semisynthetic Analogues of Manadoperoxide B Reveal New Structural Requirements for Trypanocidal Activity

    Science.gov (United States)

    Chianese, Giuseppina; Scala, Fernando; Calcinai, Barbara; Cerrano, Carlo; Dien, Henny A.; Kaiser, Marcel; Tasdemir, Deniz; Taglialatela-Scafati, Orazio

    2013-01-01

    Chemical analysis of the Indonesian sponge Plakortis cfr. lita afforded two new analogues of the potent trypanocidal agent manadoperoxide B (1), namely 12-isomanadoperoxide B (2) and manadoperoxidic acid B (3). These compounds were isolated along with a new short chain dicarboxylate monoester (4), bearing some interesting relationships with the polyketide endoperoxides found in this sponge. Some semi-synthetic analogues of manadoperoxide B (6–8) were prepared and evaluated for antitrypanosomal activity and cytotoxicity. These studies revealed crucial structure–activity relationships that should be taken into account in the design of optimized and simplified endoperoxyketal trypanocidal agents. PMID:23989650

  5. Natural and Semisynthetic Analogues of Manadoperoxide B Reveal New Structural Requirements for Trypanocidal Activity

    Directory of Open Access Journals (Sweden)

    Orazio Taglialatela-Scafati

    2013-08-01

    Full Text Available Chemical analysis of the Indonesian sponge Plakortis cfr. lita afforded two new analogues of the potent trypanocidal agent manadoperoxide B (1, namely 12-isomanadoperoxide B (2 and manadoperoxidic acid B (3. These compounds were isolated along with a new short chain dicarboxylate monoester (4, bearing some interesting relationships with the polyketide endoperoxides found in this sponge. Some semi-synthetic analogues of manadoperoxide B (6–8 were prepared and evaluated for antitrypanosomal activity and cytotoxicity. These studies revealed crucial structure–activity relationships that should be taken into account in the design of optimized and simplified endoperoxyketal trypanocidal agents.

  6. Gut peptide GLP-1 and its analogue, Exendin-4, decrease alcohol intake and reward.

    Directory of Open Access Journals (Sweden)

    Rozita H Shirazi

    Full Text Available Glucagon-like-peptide-1 (GLP-1 is a gut- and neuro-peptide with an important role in the regulation of food intake and glucose metabolism. Interestingly, GLP-1 receptors (GLP-1R are expressed in key mesolimbic reward areas (including the ventral tegmental area, VTA, innervated by hindbrain GLP-1 neurons. Recently GLP-1 has emerged as a potential regulator of food reward behavior, an effect driven by the mesolimbic GLP-1Rs. Its role in other reward behaviors remains largely unexplored. Since a considerable overlap has been suggested for circuitry controlling reward behavior derived from food and alcohol we hypothesized that GLP-1 and GLP-1Rs could regulate alcohol intake and alcohol reward. We sought to determine whether GLP-1 or its clinically safe stable analogue, Exendin-4, reduce alcohol intake and reward. To determine the potential role of the endogenous GLP-1 in alcohol intake we evaluated whether GLP-1R antagonist, Exendin 9-39, can increase alcohol intake. Furthermore, we set out to evaluate whether VTA GLP-1R activation is sufficient to reduce alcohol intake. Male Wistar rats injected peripherally with GLP-1 or Exendin-4 reduced their alcohol intake in an intermittent access two bottle free choice drinking model. Importantly, a contribution of endogenously released GLP-1 is highlighted by our observation that blockade of GLP-1 receptors alone resulted in an increased alcohol intake. Furthermore, GLP-1 injection reduced alcohol reward in the alcohol conditioned place preference test in mice. To evaluate the neuroanatomical substrate linking GLP-1 with alcohol intake/reward, we selectively microinjected GLP-1 or Exendin 4 into the VTA. This direct stimulation of the VTA GLP-1 receptors potently reduced alcohol intake. Our findings implicate GLP-1R signaling as a novel modulator of alcohol intake and reward. We show for the first time that VTA GLP-1R stimulation leads to reduced alcohol intake. Considering that GLP-1 analogues are already

  7. NMR characterization of the DNA binding properties of a novel Hoechst 33258 analogue peptide building block

    DEFF Research Database (Denmark)

    Bunkenborg, Jakob; Behrens, Carsten; Jacobsen, Jens Peter

    2002-01-01

    A novel aryl-bis-benzimidazole amino acid analogue of the DNA-binding compound Hoechst 33258 has recently been designed for incorporation in peptide combinatorial libraries by replacing the N-methylpiperazine group with a carboxyl group and the hydroxy group with an amino-methyl group. The DNA......-binding properties of the aryl-bis-benzimidazole monomer with the C-terminus derivatized with 3-(dimethylamino)-propylamine has been investigated in this paper by (1)H NMR studies of two different complexes with two different DNA sequences: A(5) d(5'-GCCA(5)CG-3'):d(5'-CGT(5)GGC-3') and A(3)T(3) d(5'-CGA(3)T(3)CG-3...... preference with the bis-benzimidazole moiety displaced toward the 3'-end from the center of the duplex. Two families of models of the complexes with A(5) and A(3)T(3) were derived with restrained molecular dynamics based on a large set of 70 and 61, respectively, intermolecular ligand NOEs. Both models give...

  8. Glucagon-like peptide-1 analogue prevents nonalcoholic steatohepatitis in non-obese mice.

    Science.gov (United States)

    Yamamoto, Takaya; Nakade, Yukiomi; Yamauchi, Taeko; Kobayashi, Yuji; Ishii, Norimitsu; Ohashi, Tomohiko; Ito, Kiyoaki; Sato, Ken; Fukuzawa, Yoshitaka; Yoneda, Masashi

    2016-02-28

    To investigate whether a glucagon-like peptide-1 (GLP-1) analogue inhibits nonalcoholic steatohepatitis (NASH), which is being increasingly recognized in Asia, in non-obese mice. A methionine-choline-deficient diet (MCD) along with exendin-4 (20 μg/kg per day, ip), a GLP-1 analogue, or saline was administered to male db/db mice (non-obese NASH model). Four or eight weeks after commencement of the diet, the mice were sacrificed and their livers were excised. The excised livers were examined by histochemistry for evidence of hepatic steatosis and inflammation. Hepatic triglyceride (TG) and free fatty acid (FFA) content was measured, and the expression of hepatic fat metabolism- and inflammation-related genes was evaluated. Oxidative stress-related parameters and macrophage recruitment were also examined using immunohistochemistry. Four weeks of MCD feeding induced hepatic steatosis and inflammation and increased the hepatic TG and FFA content. The expression of fatty acid transport protein 4 (FATP4), a hepatic FFA influx-related gene; macrophage recruitment; and the level of malondialdehyde (MDA), an oxidative stress marker, were significantly augmented by a 4-wk MCD. The levels of hepatic sterol regulatory element-binding protein-1c (SREBP-1c) mRNA (lipogenesis-related gene) and acyl-coenzyme A oxidase 1 (ACOX1) mRNA (β-oxidation-related gene) had decreased at 4 wk and further decreased at 8 wk. However, the level of microsomal triglyceride transfer protein mRNA (a lipid excretion-related gene) remained unchanged. The administration of exendin-4 significantly attenuated the MCD-induced increase in hepatic steatosis, hepatic TG and FFA content, and FATP4 expression as well as the MCD-induced augmentation of hepatic inflammation, macrophage recruitment, and MDA levels. Additionally, it further decreased the hepatic SREBP-1c level and alleviated the MCD-mediated inhibition of the ACOX1 mRNA level. These results suggest that GLP-1 inhibits hepatic steatosis and

  9. Antibacterial and anti-inflammatory activity of a temporin B peptide analogue on an in vitro model of cystic fibrosis.

    Science.gov (United States)

    Bezzerri, Valentino; Avitabile, Concetta; Dechecchi, Maria Cristina; Lampronti, Ilaria; Borgatti, Monica; Montagner, Giulia; Cabrini, Giulio; Gambari, Roberto; Romanelli, Alessandra

    2014-10-01

    Natural peptides with antimicrobial properties are deeply investigated as tools to fight bacteria resistant to common antibiotics. Small peptides, as those belonging to the temporin family, are very attractive because their activity can easily be tuned after small modification to their primary sequence. Structure-activity studies previously reported by us allowed the identification of one peptide, analogue of temporin B, TB_KKG6A, showing, unlike temporin B, antimicrobial activity against both Gram-positive and Gram-negative bacteria. In this paper, we investigated the antimicrobial and anti-inflammatory activity of the peptide TB_KKG6A against Pseudomonas aeruginosa. Interestingly, we found that the peptide exhibits antimicrobial activity at low concentrations, being able to downregulate the pro-inflammatory chemokines and cytokines interleukin (IL)-8, IL-1β, IL-6 and tumor necrosis factor-α produced downstream infected human bronchial epithelial cells. Experiments were carried out also with temporin B, which was found to show pro-inflammatory activity. Details on the interaction between TB_KKG6A and the P. aeruginosa LPS were obtained by circular dichroism and fluorescence studies. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  10. Antimicrobial activity of analogues of a peptide isolated from venom glands of social wasps Polistes major major inhabiting the Dominican Republic

    Czech Academy of Sciences Publication Activity Database

    Ježek, Rudolf; Šebestík, Jaroslav; Šafařík, Martin; Borovičková, Lenka; Fučík, Vladimír; Čeřovský, Václav; Slaninová, Jiřina

    2008-01-01

    Roč. 14, č. 8 (2008), s. 99-99 ISSN 1075-2617. [European Peptide Symposium /30./. 31.08.2008-05.09.2008, Helsinki] Institutional research plan: CEZ:AV0Z40550506 Keywords : peptides from venom glands * Polistes major * synthesis and antimicrobial activity * analogues Subject RIV: CC - Organic Chemistry

  11. One Peptide Reveals the Two Faces of α-Helix Unfolding-Folding Dynamics.

    Science.gov (United States)

    Jesus, Catarina S H; Cruz, Pedro F; Arnaut, Luis G; Brito, Rui M M; Serpa, Carlos

    2018-04-12

    The understanding of fast folding dynamics of single α-helices comes mostly from studies on rationally designed peptides displaying sequences with high helical propensity. The folding/unfolding dynamics and energetics of α-helix conformations in naturally occurring peptides remains largely unexplored. Here we report the study of a protein fragment analogue of the C-peptide from bovine pancreatic ribonuclease-A, RN80, a 13-amino acid residue peptide that adopts a highly populated helical conformation in aqueous solution. 1 H NMR and CD structural studies of RN80 showed that α-helix formation displays a pH-dependent bell-shaped curve, with a maximum near pH 5, and a large decrease in helical content in alkaline pH. The main forces stabilizing this short α-helix were identified as a salt bridge formed between Glu-2 and Arg-10 and the cation-π interaction involving Tyr-8 and His-12. Thus, deprotonation of Glu-2 or protonation of His-12 are essential for the RN80 α-helix stability. In the present study, RN80 folding and unfolding were triggered by laser-induced pH jumps and detected by time-resolved photoacoustic calorimetry (PAC). The photoacid proton release, amino acid residue protonation, and unfolding/folding events occur at different time scales and were clearly distinguished using time-resolved PAC. The partial unfolding of the RN80 α-helix, due to protonation of Glu-2 and consequent breaking of the stabilizing salt bridge between Glu-2 and Arg-10, is characterized by a concentration-independent volume expansion in the sub-microsecond time range (0.8 mL mol -1 , 369 ns). This small volume expansion reports the cost of peptide backbone rehydration upon disruption of a solvent-exposed salt bridge, as well as backbone intrinsic expansion. On the other hand, RN80 α-helix folding triggered by His-12 protonation and subsequent formation of a cation-π interaction leads to a microsecond volume contraction (-6.0 mL mol -1 , ∼1.7 μs). The essential role of two

  12. Tumour uptake of the radiolabelled somatostatin analogue [DOTA0,TYR3]octreotide is dependent on the peptide amount

    International Nuclear Information System (INIS)

    Jong, M. de; Breeman, W.A.P.; Bernard, B.F.; Gameren, A. van; Bruin, E. de; Bakker, W.H.; Van der Pluijm, M.E.; Krenning, E.P.; Visser, T.J.; Maecke, H.R.

    1999-01-01

    Radiolabelled tumour receptor-binding peptides can be used for in vivo scintigraphic imaging. Recently, the somatostatin analogue [Tyr 3 ]octreotide (d-Phe-c(Cys-Tyr-d-Trp-Lys-Thr-Cys)-Thr(ol)) was derivatized with the chelator DOTA (tetra-azacyclododecane-tetra-acetic acid), enabling stable radiolabelling with both the high-energy beta particle-emitter yttrium-90 and the Auger electron-emitter indium-111. The thus produced radiolabelled compounds are promising for peptide receptor radionuclide therapy. Our previous in vitro and in vivo (rat) experiments with these radiolabelled compounds showed favourable binding and biodistribution characteristics with high uptake and retention in the target organs. We also demonstrated receptor-specific, time- and temperature-dependent internalization of radiolabelled [DOTA 0 ,Tyr 3 ]octreotide in somatostatin receptor subtype 2 (sst 2 )-positive rat pancreatic tumour cell lines. In this study we have investigated the effects of differences in the amount of injected peptide on tissue distribution of 111 In-labelled [DOTA 0 ,Tyr 3 ]octreotide in normal, i.e. non-tumour-bearing, and CA20948 tumour-bearing rats. This was done in order to find the amount of peptide at which the highest uptake in target tissues is achieved, and thereby to increase the potential of radionuclide therapy while simultaneously ensuring the lowest possible radiotoxicity in normal organs. Uptake of radiolabelled [DOTA 0 ,Tyr 3 ]octreotide in sst 2 -positive organs showed different bell-shaped functions of the amount of injected peptide, being highest at 0.05 (adrenals), 0.05-0.1 (pituitary and stomach) and 0.25 (pancreas) μg. Uptake in the tumour was highest at 0.5 μg injected peptide. The highest uptake was found at peptide amounts that were lower than those reported for [ 111 In-DTPA 0 ]octreotide (d-Phe-c(Cys-Phe-d-Trp-Lys-Thr-Cys)-Thr(ol), DTPA = diethylene-triamine-penta-acetic acid), consistent with the higher receptor affinity of the first compound

  13. 111In-labeled lactam bridge-cyclized alpha-melanocyte stimulating hormone peptide analogues for melanoma imaging.

    Science.gov (United States)

    Miao, Yubin; Gallazzi, Fabio; Guo, Haixun; Quinn, Thomas P

    2008-02-01

    The purpose of this study was to examine the influence of the lactam bridge cyclization on melanoma targeting and biodistribution properties of the radiolabeled conjugates. Two novel lactam bridge-cyclized alpha-MSH peptide analogues, DOTA-CycMSH (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]) and DOTA-GlyGlu-CycMSH (DOTA-Gly-Glu-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]), were synthesized and radiolabeled with (111)In. The internalization and efflux of (111)In-labeled CycMSH peptides were examined in B16/F1 melanoma cells. The melanoma targeting properties, pharmacokinetics, and SPECT/CT imaging of (111)In-labeled CycMSH peptides were determined in B16/F1 melanoma-bearing C57 mice. Both (111)In-DOTA-CycMSH and (111)In-DOTA-GlyGlu-CycMSH exhibited fast internalization and extended retention in B16/F1 cells. The tumor uptake values of (111)In-DOTA-CycMSH and (111)In-DOTA-GlyGlu-CycMSH were 9.53+/-1.41% injected dose/gram (% ID/g) and 10.40+/-1.40% ID/g at 2 h postinjection, respectively. Flank melanoma tumors were clearly visualized with (111)In-DOTA-CycMSH and (111)In-DOTA-GlyGlu-CycMSH by SPECT/CT images at 2 h postinjection. Whole-body clearance of the peptides was fast, with greater than 90% of the radioactivities cleared through urinary system by 2 h postinjection. There was low radioactivity (<0.8% ID/g) accumulated in blood and normal organs except kidneys at all time points investigated. Introduction of a negatively charged linker (-Gly-Glu-) into the peptide sequence decreased the renal uptake by 44% without affecting the tumor uptake at 4 h postinjection. High receptor-mediated melanoma uptakes coupled with fast whole-body clearance in B16/F1 melanoma-bearing C57 mice demonstrated the feasibility of using (111)In-labeled lactam bridge-cyclized alpha-MSH peptide analogues as a novel class of imaging probes for receptor-targeting melanoma imaging.

  14. Use of synthetic analogues in confirmation of structure of the peptide antibiotics Maltacines

    Science.gov (United States)

    Hagelin, Gunnar; Indrevoll, Bård; Hoeg-Jensen, Thomas

    2007-12-01

    Maltacines comprise a family of cyclic peptide lactone antibiotics produced by a strain of Bacillus subtilis. The previously proposed amino acid sequences of the linear ring-opened molecules show similarity to the lipopeptide antibiotic Fengycin IX that is also produced by a strain of B. subtilisE There were some discrepancies in the Maltacin data that could not be explained. To address this and gain more information into the structure of the linear ring-opened Maltacines, the two members D1c, E1b and Fengycin IX acid were synthesised and their MS2, MS3 and MS4 spectra compared. The similarity of the product ion spectra of Maltacin and Fengycin IX acid revealed that proline occupies an internal position in Maltacin. This finding led to revision of the interpretation of the amino acid sequences of the Maltacines. The proposed new structures of the Maltacines shows that the cyclic part of the molecules is the same as in Fengycin IX acid and Fengycin XII acid, but they have unique N-terminal sequences not found in Fengycins, and thus represent novel lipopeptide antibiotics.

  15. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus.

    Science.gov (United States)

    Gottschalk, Sanne; Gottlieb, Caroline T; Vestergaard, Martin; Hansen, Paul R; Gram, Lone; Ingmer, Hanne; Thomsen, Line E

    2015-12-01

    The rapid rise in antibiotic-resistant pathogens is causing increased health concerns, and consequently there is an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs), which have been isolated from a wide range of organisms, represent a very promising class of novel antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl(2) concentrations and at alkaline pH, while it was compromised by acidic pH and exposure to serum. Furthermore, at subinhibitory concentrations of FL9, S. aureus responded by increasing the expression of two major virulence factor genes, namely the regulatory rnaIII and hla, encoding α-haemolysin. In addition, the S. aureus-encoded natural tolerance mechanisms included peptide cleavage and the addition of positive charge to the cell surface, both of which minimized the antimicrobial activity of FL9. Our results add new information about FL9 and its effect on S. aureus, which may aid in the future development of analogues with improved therapeutic potential.

  16. Amphibian antimicrobial peptide fallaxin analogue FL9 affects virulence gene expression and DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Gottlieb, Caroline Trebbien; Vestergaard, Martin

    2015-01-01

    antimicrobials. In the present study, the analogue FL9, based on the amphibian AMP fallaxin, was studied to elucidate its mode of action and antibacterial activity against the human pathogen Staphylococcus aureus. Our data showed that FL9 may have a dual mode of action against S. aureus. At concentrations around...... and at alkaline pH, while it was compromised by acidic pH and exposure to serum. Furthermore, at subinhibitory concentrations of FL9, S. aureus responded by increasing the expression of two major virulence factor genes, namely the regulatory rnaIII and hla, encoding α-haemolysin. In addition, the S. aureus...... the MIC, FL9 bound DNA, inhibited DNA synthesis and induced the SOS DNA damage response, whereas at concentrations above the MIC the interaction between S. aureus and FL9 led to membrane disruption. The antibacterial activity of the peptide was maintained over a wide range of NaCl and MgCl2 concentrations...

  17. Novel peptide chemistry in terrestrial animals: natural luciferin analogues from the bioluminescent earthworm Fridericia heliota.

    Science.gov (United States)

    Dubinnyi, Maxim A; Tsarkova, Aleksandra S; Petushkov, Valentin N; Kaskova, Zinaida M; Rodionova, Natalja S; Kovalchuk, Sergey I; Ziganshin, Rustam H; Baranov, Mikhail S; Mineev, Konstantin S; Yampolsky, Ilia V

    2015-03-02

    We report isolation and structure elucidation of AsLn5, AsLn7, AsLn11 and AsLn12: novel luciferin analogs from the bioluminescent earthworm Fridericia heliota. They were found to be highly unusual modified peptides, comprising either of the two tyrosine-derived chromophores, CompX or CompY and a set of amino acids, including threonine, gamma-aminobutyric acid, homoarginine, and unsymmetrical N,N-dimethylarginine. These natural compounds represent a unique peptide chemistry found in terrestrial animals and rise novel questions concerning their biosynthetic origin. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Streptococcal adhesin SspA/B analogue peptide inhibits adherence and impacts biofilm formation of Streptococcus mutans.

    Directory of Open Access Journals (Sweden)

    Tatsuro Ito

    Full Text Available Streptococcus mutans, the major causative agent of dental caries, adheres to tooth surfaces via the host salivary glycoprotein-340 (gp340. This adherence can be competitively inhibited by peptides derived from the SspA/B adhesins of Streptococcus gordonii, a human commensal microbe that competes for the same binding sites. Ssp(A4K-A11K, a double-lysine substituted SspA/B peptide analogue, has been shown to exhibit superior in vitro binding affinity for a gp340-derived peptide (SRCRP2, suggesting that Ssp(A4K-A11K may be of clinical interest. In the present work, we tested the inhibitory effects of Ssp(A4K-A11K on adherence and biofilm formation of S. mutans by reconstructing an artificial oral environment using saliva-coated polystyrene plates and hydroxyapatite disks. Bacterial adherence (adherence period: 1 h was assessed by an enzyme-linked immunosorbent assay using biotinylated bacterial cells. Biofilm formation (periods: 8, 11, or 14 h was assessed by staining and imaging of the sessile cells, or by recovering biofilm cells and plating for cell counts. The pH values of the culture media were measured as a biofilm acidogenicity indicator. Bactericidality was measured by loss of optical density during culturing in the presence of the peptide. We observed that 650 μM Ssp(A4K-A11K significantly inhibited adherence of S. mutans to saliva-coated polystyrene; a similar effect was seen on bacterial affinity for SRCRP2. Ssp(A4K-A11K had lesser effects on the adherence of commensal streptococci. Pretreatment of polystyrene and hydroxyapatite with 650 μM Ssp(A4K-A11K significantly attenuated biofilm formation, whether tested with glucose- or sucrose-containing media. The SspA/B peptide's activity did not reflect bactericidality. Strikingly, pH in Ssp-treated 8-h (6.8 ± 0.06 and 11-h (5.5 ± 0.06 biofilms showed higher values than the critical pH. Thus, Ssp(A4K-A11K acts by inhibiting bacterial adherence and cariogrnic biofilm formation. We further

  19. Quantitative evaluation of peptide analogue distribution in mouse tissue using 3D computer modelling

    DEFF Research Database (Denmark)

    Jensen, Casper Bo

    histology sections. The work demonstrates the use of automated image analysis based on image registration to quantify LSFM data of the peptide brain distribution following peripheral administration. The methodology was expanded during the PhD work to also include study of receptor mapping and brain...

  20. Virtual screening using combinatorial cyclic peptide libraries reveals protein interfaces readily targetable by cyclic peptides.

    Science.gov (United States)

    Duffy, Fergal J; O'Donovan, Darragh; Devocelle, Marc; Moran, Niamh; O'Connell, David J; Shields, Denis C

    2015-03-23

    Protein-protein and protein-peptide interactions are responsible for the vast majority of biological functions in vivo, but targeting these interactions with small molecules has historically been difficult. What is required are efficient combined computational and experimental screening methods to choose among a number of potential protein interfaces worthy of targeting lead macrocyclic compounds for further investigation. To achieve this, we have generated combinatorial 3D virtual libraries of short disulfide-bonded peptides and compared them to pharmacophore models of important protein-protein and protein-peptide structures, including short linear motifs (SLiMs), protein-binding peptides, and turn structures at protein-protein interfaces, built from 3D models available in the Protein Data Bank. We prepared a total of 372 reference pharmacophores, which were matched against 108,659 multiconformer cyclic peptides. After normalization to exclude nonspecific cyclic peptides, the top hits notably are enriched for mimetics of turn structures, including a turn at the interaction surface of human α thrombin, and also feature several protein-binding peptides. The top cyclic peptide hits also cover the critical "hot spot" interaction sites predicted from the interaction crystal structure. We have validated our method by testing cyclic peptides predicted to inhibit thrombin, a key protein in the blood coagulation pathway of important therapeutic interest, identifying a cyclic peptide inhibitor with lead-like activity. We conclude that protein interfaces most readily targetable by cyclic peptides and related macrocyclic drugs may be identified computationally among a set of candidate interfaces, accelerating the choice of interfaces against which lead compounds may be screened.

  1. Glucagon-like peptide-1 analogue, liraglutide, in experimental cerebral malaria

    DEFF Research Database (Denmark)

    Della Valle, Brian William; Hempel, Casper; Staalsoe, Trine

    2016-01-01

    (GLP-1) mimetics have potent neuroprotective effects in animal models of neuropathology associated with ROS/RNS dysfunction. This study investigates the effect of the GLP-1 analogue, liraglutide against the clinical outcome of experimental cerebral malaria (ECM) and Plasmodium falciparum growth....... Furthermore the role of oxidative stress on ECM pathogenesis is evaluated. METHODS: ECM was induced in Plasmodium berghei ANKA-infected C57Bl/6j mice. Infected Balb/c (non-cerebral malaria) and uninfected C57Bl/6j mice were included as controls. Mice were treated twice-daily with vehicle or liraglutide (200...... were quantified. RESULTS: The development and progression of ECM was not affected by liraglutide. Indeed, although ROS/RNS were increased in peripheral organs, ROS/RNS generation was not present in the brain. Interestingly, CREB was activated in the ECM brain and may protect against ROS/RNS stress...

  2. Stepwise Mechanism of Temperature-Dependent Coacervation of the Elastin-like Peptide Analogue Dimer, (C(WPGVG)3)2.

    Science.gov (United States)

    Tatsubo, Daiki; Suyama, Keitaro; Miyazaki, Masaya; Maeda, Iori; Nose, Takeru

    2018-03-13

    Elastin-like peptides (ELPs) are distinct, repetitive, hydrophobic sequences, such as (VPGVG) n , that exhibit coacervation, the property of reversible, temperature-dependent self-association and dissociation. ELPs can be found in elastin and have been developed as new scaffold biomaterials. However, the detailed relationship between their amino acid sequences and coacervation properties remains obscure because of the structural flexibility of ELPs. In this study, we synthesized a novel, dimeric ELP analogue (H-C(WPGVG) 3 -NH 2 ) 2 , henceforth abbreviated (CW3)2, and analyzed its self-assembly properties and structural factors as indicators of coacervation. Turbidity measurements showed that (CW3)2 demonstrated coacervation at a concentration much lower than that of its monomeric form and another ELP. In addition, the coacervate held water-soluble dye molecules. Thus, potent and distinct coacervation was obtained with a remarkably short sequence of (CW3)2. Furthermore, fluorescence microscopy, dynamic light scattering, and optical microscopy revealed that the coacervation of (CW3)2 was a stepwise process. The structural factors of (CW3)2 were analyzed by molecular dynamics simulations and circular dichroism spectroscopy. These measurements indicated that helical structures primarily consisting of proline and glycine became more disordered at high temperatures with concurrent, significant exposure of their hydrophobic surfaces. This extreme change in the hydrophobic surface contributes to the potent coacervation observed for (CW3)2. These results provide important insights into more efficient applications of ELPs and their analogues, as well as the coacervation mechanisms of ELP and elastin.

  3. Biologically relevant conformational features of linear and cyclic proteolipid protein (PLP) peptide analogues obtained by high-resolution nuclear magnetic resonance and molecular dynamics

    Science.gov (United States)

    Kordopati, Golfo G.; Tzoupis, Haralambos; Troganis, Anastassios N.; Tsivgoulis, Gerasimos M.; Golic Grdadolnik, Simona; Simal, Carmen; Tselios, Theodore V.

    2017-09-01

    Proteolipid protein (PLP) is one of the main proteins of myelin sheath that are destroyed during the progress of multiple sclerosis (MS). The immunodominant PLP139-151 epitope is known to induce experimental autoimmune encephalomyelitis (EAE, animal model of MS), wherein residues 144 and 147 are recognized by T cell receptor (TCR) during the formation of trimolecular complex with peptide-antigen and major histocompability complex. The conformational behavior of linear and cyclic peptide analogues of PLP, namely PLP139-151 and cyclic (139-151) (L144, R147) PLP139-151, have been studied in solution by means of nuclear magnetic resonance (NMR) methods in combination with unrestrained molecular dynamics simulations. The results indicate that the side chains of mutated amino acids in the cyclic analogue have different spatial orientation compared with the corresponding side chains of the linear analogue, which can lead to reduced affinity to TCR. NMR experiments combined with theoretical calculations pave the way for the design and synthesis of potent restricted peptides of immunodominant PLP139-151 epitope as well as non peptide mimetics that rises as an ultimate goal.

  4. In vitro Evaluation of a Bombesin Antagonistic Analogue Conjugated with DOTA-Ala(SO3H)-Aminooctanoyl for Targeting of the Gastrin-releasing Peptide Receptor

    International Nuclear Information System (INIS)

    Lim, Jae Cheong; Cho, Eun Ha; Kim, Jin Joo; Lee, So Young; Choi, Sang Mu

    2014-01-01

    As Bombesin (BBS) binds with high affinity to GRPR, BBS derivatives have been labeled with various radionuclides such as 99 mTc, 111 In, 90 Y, 64 Cu, 177 Lu, 68 Ga, or 18 F and have proved to be successful candidates for peptide receptor radiotherapy (PRRT). In this study, we employed Ala(SO 3 H)-Aminooctanoyl as a linker of BBS antagonistic peptide sequence, Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-NH 2 , with DOTA to prepare radiolabeled candidates for GRPR targeting. A DOTA-conjugated BBS antagonistic analogue was synthesized and radiolabeled with 177 Lu, and in vitro characteristics on GRPR-overexpressing human prostate tumor cells were evaluated. In conclusion, a novel BBS antagonistic analogue, 177 Lu-DOTA-sBBNA, is a promising candidate for the targeting of GRPR-over-expressing tumors. Further investigations to evaluate its in vivo characteristics and therapeutic efficacy are needed

  5. Synthetic Strigolactone Analogues Reveal Anti-Cancer Activities on Hepatocellular Carcinoma Cells

    KAUST Repository

    Hasan, Mohammed Nihal

    2018-02-09

    Hepatocellular carcinoma (HCC) remains one of the leading causes of death worldwide. The complex etiology is attributed to many factors like heredity, cirrhosis, hepatitis infections or the dysregulation of the different molecular pathways. Nevertheless, the current treatment regimens have either severe side effects or tumors gradually acquire resistance upon prolonged use. Thus, developing a new selective treatment for HCC is the need of the hour. Many anticancer agents derived from plants have been evaluated for their cytotoxicity towards many human cancer cell lines. Strigolactones (SLs)-a newly discovered class of phytohormones, play a crucial role in the development of plant-root and shoot. Recently, many synthetic analogues of SLs have demonstrated pro-apoptotic effects on different cancer cell lines like prostate, breast, colon and lung. In this study, we tested synthetic SLs analogues on HCC cell line-HepG2 and evaluated their capability to induce cell proliferation inhibition and apoptosis. Primary WST-1 assays, followed by annexin-V/7AAD staining, demonstrated the anti-proliferative effects. The SLs analogues TIT3 and TIT7 were found to significantly reduce HepG2 cell viability in a dose- and time-dependent manner and induce apoptosis. Interestingly, though TIT3 and TIT7 strongly affected cancer cell proliferation, both compounds showed moderate anti-proliferative effect on normal cells. Further, migration of cancer cells was suppressed upon treatment with TIT3 and TIT7 in a wound healing assay. In summary, these findings suggest that two SLs analogues TIT3 and TIT7 exert selective inhibitory effects on cancer cells most likely through targeting microtubules. SLs analogues could be used in future as potential anti-cancer candidates in chemotherapy.

  6. Synthetic Strigolactone Analogues Reveal Anti-Cancer Activities on Hepatocellular Carcinoma Cells

    KAUST Repository

    Hasan, Mohammed Nihal; Choudhry, Hani; Razvi, Syed Shoeb; Moselhy, Said Salama; Kumosani, Taha Abduallah; Zamzami, Mazin A.; Omran, Ziad; Halwani, Majed A.; Al-Babili, Salim; Abualnaja, Khalid Omer; Al-Malki, Abdulrahman Labeed; Alhosin, Mahmoud; Asami, Tadao

    2018-01-01

    Hepatocellular carcinoma (HCC) remains one of the leading causes of death worldwide. The complex etiology is attributed to many factors like heredity, cirrhosis, hepatitis infections or the dysregulation of the different molecular pathways. Nevertheless, the current treatment regimens have either severe side effects or tumors gradually acquire resistance upon prolonged use. Thus, developing a new selective treatment for HCC is the need of the hour. Many anticancer agents derived from plants have been evaluated for their cytotoxicity towards many human cancer cell lines. Strigolactones (SLs)-a newly discovered class of phytohormones, play a crucial role in the development of plant-root and shoot. Recently, many synthetic analogues of SLs have demonstrated pro-apoptotic effects on different cancer cell lines like prostate, breast, colon and lung. In this study, we tested synthetic SLs analogues on HCC cell line-HepG2 and evaluated their capability to induce cell proliferation inhibition and apoptosis. Primary WST-1 assays, followed by annexin-V/7AAD staining, demonstrated the anti-proliferative effects. The SLs analogues TIT3 and TIT7 were found to significantly reduce HepG2 cell viability in a dose- and time-dependent manner and induce apoptosis. Interestingly, though TIT3 and TIT7 strongly affected cancer cell proliferation, both compounds showed moderate anti-proliferative effect on normal cells. Further, migration of cancer cells was suppressed upon treatment with TIT3 and TIT7 in a wound healing assay. In summary, these findings suggest that two SLs analogues TIT3 and TIT7 exert selective inhibitory effects on cancer cells most likely through targeting microtubules. SLs analogues could be used in future as potential anti-cancer candidates in chemotherapy.

  7. Development of a new family of conformationally restricted peptides as potent nucleators of beta-turns. Design, synthesis, structure, and biological evaluation of a beta-lactam peptide analogue of melanostatin.

    Science.gov (United States)

    Palomo, Claudio; Aizpurua, Jesus M; Benito, Ana; Miranda, José Ignacio; Fratila, Raluca M; Matute, Carlos; Domercq, Maria; Gago, Federico; Martin-Santamaria, Sonsoles; Linden, Anthony

    2003-12-31

    Novel enantiopure (i)-(beta-lactam)-(Gly)-(i+3) peptide models, defined by the presence of a central alpha-alkyl-alpha-amino-beta-lactam ring placed as the (i+1) residue, have been synthesized in a totally stereocontrolled way by alpha-alkylation of suitable N-[bis(trimethylsilyl)methyl]-beta-lactams. The structural properties of these beta-lactam pseudopeptides have been studied by X-ray crystallography, Molecular Dynamics simulation, and NOESY-restrained NMR simulated annealing techniques, showing a strong tendency to form stable type II or type II' beta-turns either in the solid state or in highly coordinating DMSO solutions. Tetrapeptide models containing syn- or anti-alpha,beta-dialkyl-alpha-amino-beta-lactam rings have also been synthesized and their conformations analyzed, revealing that alpha-alkyl substitution is essential for beta-turn stabilization. A beta-lactam analogue of melanostatin (PLG amide) has also been prepared, characterized as a type-II beta-turn in DMSO-d6 solution, and tested by competitive binding assay as a dopaminergic D2 modulator in rat neuron cultured cells, displaying moderate agonist activity in the micromolar concentration range. On the basis of these results, a novel peptidomimetic design concept, based on the separation of constraint and recognition elements, is proposed.

  8. Effect of the Glucagon-like Peptide-1 Analogue Exenatide Extended Release in Cats with Newly Diagnosed Diabetes Mellitus.

    Science.gov (United States)

    Riederer, A; Zini, E; Salesov, E; Fracassi, F; Padrutt, I; Macha, K; Stöckle, T M; Lutz, T A; Reusch, C E

    2016-01-01

    Exenatide extended release (ER) is a glucagon-like peptide-1 analogue that increases insulin secretion, inhibits glucagon secretion and induces satiation in humans with type 2 diabetes mellitus. The use of exenatide ER is safe and stimulates insulin secretion in healthy cats. The objective of this study is to assess the safety of exenatide ER and its effect on body weight, remission and metabolic control in newly diagnosed diabetic cats receiving insulin and a low-carbohydrate diet. Thirty client-owned cats. Prospective placebo-controlled clinical trial. Cats were treated with exenatide ER or 0.9% saline, administered SC, once weekly. Both groups received insulin glargine and a low-carbohydrate diet. Exenatide ER was administered for 16 weeks, or in cats that achieved remission it was given for 4 weeks after discontinuing insulin treatment. Nonparametric tests were used for statistical analysis. Cats in the exenatide ER and placebo groups had transient adverse signs including decreased appetite (60% vs. 20%, respectively, P = .06) and vomiting (53% vs. 40%, respectively, P = .715). Body weight increased significantly in the placebo group (P = .002), but not in cats receiving exenatide ER. Cats on exenatide ER achieved remission or good metabolic control in 40% or 89%, respectively, whereas in control cats percentages were 20% or 58% (P = .427 and P = .178, respectively). Exenatide ER is safe in diabetic cats and does not result in weight gain. Our pilot study suggests that, should there be an additional clinically relevant beneficial effect of exenatide ER in insulin-treated cats on rate of remission and good metabolic control, it would likely approximate 20% and 30%, respectively. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  9. Glucagon-like peptide 1 analogue therapy directly modulates innate immune-mediated inflammation in individuals with type 2 diabetes mellitus.

    Science.gov (United States)

    Hogan, Andrew E; Gaoatswe, Gadintshware; Lynch, Lydia; Corrigan, Michelle A; Woods, Conor; O'Connell, Jean; O'Shea, Donal

    2014-04-01

    Glucagon-like peptide 1 (GLP-1) is a gut hormone used in the treatment of type 2 diabetes mellitus. There is emerging evidence that GLP-1 has anti-inflammatory activity in humans, with murine studies suggesting an effect on macrophage polarisation. We hypothesised that GLP-1 analogue therapy in individuals with type 2 diabetes mellitus would affect the inflammatory macrophage molecule soluble CD163 (sCD163) and adipocytokine profile. We studied ten obese type 2 diabetes mellitus patients starting GLP-1 analogue therapy at a hospital-based diabetes service. We investigated levels of sCD163, TNF-α, IL-1β, IL-6, adiponectin and leptin by ELISA, before and after 8 weeks of GLP-1 analogue therapy. GLP-1 analogue therapy reduced levels of the inflammatory macrophage activation molecule sCD163 (220 ng/ml vs 171 ng/ml, p < 0.001). This occurred independent of changes in body weight, fructosamine and HbA1c. GLP-1 analogue therapy was associated with a decrease in levels of the inflammatory cytokines TNF-α (264 vs 149 pg/ml, p < 0.05), IL-1β (2,919 vs 748 pg/ml, p < 0.05) and IL-6 (1,379 vs 461 pg/ml p < 0.05) and an increase in levels of the anti-inflammatory adipokine adiponectin (4,480 vs 6,290 pg/ml, p < 0.002). In individuals with type 2 diabetes mellitus, GLP-1 analogue therapy reduces the frequency of inflammatory macrophages. This effect is not dependent on the glycaemic or body weight effects of GLP-1.

  10. Genome-wide analyses reveal a role for peptide hormones in planarian germline development.

    Directory of Open Access Journals (Sweden)

    James J Collins

    Full Text Available Bioactive peptides (i.e., neuropeptides or peptide hormones represent the largest class of cell-cell signaling molecules in metazoans and are potent regulators of neural and physiological function. In vertebrates, peptide hormones play an integral role in endocrine signaling between the brain and the gonads that controls reproductive development, yet few of these molecules have been shown to influence reproductive development in invertebrates. Here, we define a role for peptide hormones in controlling reproductive physiology of the model flatworm, the planarian Schmidtea mediterranea. Based on our observation that defective neuropeptide processing results in defects in reproductive system development, we employed peptidomic and functional genomic approaches to characterize the planarian peptide hormone complement, identifying 51 prohormone genes and validating 142 peptides biochemically. Comprehensive in situ hybridization analyses of prohormone gene expression revealed the unanticipated complexity of the flatworm nervous system and identified a prohormone specifically expressed in the nervous system of sexually reproducing planarians. We show that this member of the neuropeptide Y superfamily is required for the maintenance of mature reproductive organs and differentiated germ cells in the testes. Additionally, comparative analyses of our biochemically validated prohormones with the genomes of the parasitic flatworms Schistosoma mansoni and Schistosoma japonicum identified new schistosome prohormones and validated half of all predicted peptide-encoding genes in these parasites. These studies describe the peptide hormone complement of a flatworm on a genome-wide scale and reveal a previously uncharacterized role for peptide hormones in flatworm reproduction. Furthermore, they suggest new opportunities for using planarians as free-living models for understanding the reproductive biology of flatworm parasites.

  11. A Cyclic Altered Peptide Analogue Based on Myelin Basic Protein 87-99 Provides Lasting Prophylactic and Therapeutic Protection Against Acute Experimental Autoimmune Encephalomyelitis.

    Science.gov (United States)

    Emmanouil, Mary; Tseveleki, Vivian; Triantafyllakou, Iro; Nteli, Agathi; Tselios, Theodore; Probert, Lesley

    2018-01-31

    In this report, amide-linked cyclic peptide analogues of the 87-99 myelin basic protein (MBP) epitope, a candidate autoantigen in multiple sclerosis (MS), are tested for therapeutic efficacy in experimental autoimmune encephalomyelitis (EAE). Cyclic altered peptide analogues of MBP 87-99 with substitutions at positions 91 and/or 96 were tested for protective effects when administered using prophylactic or early therapeutic protocols in MBP 72-85 -induced EAE in Lewis rats. The Lys 91 and Pro 96 of MBP 87-99 are crucial T-cell receptor (TCR) anchors and participate in the formation of trimolecular complex between the TCR-antigen (peptide)-MHC (major histocompability complex) for the stimulation of encephalitogenic T cells that are necessary for EAE induction and are implicated in MS. The cyclic peptides were synthesized using Solid Phase Peptide Synthesis (SPPS) applied on the 9-fluorenylmethyloxycarboxyl/tert-butyl Fmoc/tBu methodology and combined with the 2-chlorotrityl chloride resin (CLTR-Cl). Cyclo(91-99)[Ala 96 ]MBP 87-99 , cyclo(87-99)[Ala 91,96 ]MBP 87-99 and cyclo(87-99)[Arg 91 , Ala 96 ]MBP 87-99 , but not wild-type linear MBP 87-99 , strongly inhibited MBP 72-85 -induced EAE in Lewis rats when administered using prophylactic and early therapeutic vaccination protocols. In particular, cyclo(87-99)[Arg 91 , Ala 96 ]MBP 87-99 was highly effective in preventing the onset and development of clinical symptoms and spinal cord pathology and providing lasting protection against EAE induction.

  12. A novel peptide sansalvamide analogue inhibits pancreatic cancer cell growth through G0/G1 cell-cycle arrest

    International Nuclear Information System (INIS)

    Ujiki, Michael B.; Milam, Ben; Ding Xianzhong; Roginsky, Alexandra B.; Salabat, M. Reza; Talamonti, Mark S.; Bell, Richard H.; Gu Wenxin; Silverman, Richard B.; Adrian, Thomas E.

    2006-01-01

    Patients with pancreatic cancer have little hope for cure because no effective therapies are available. Sansalvamide A is a cyclic depsipeptide produced by a marine fungus. We investigated the effect of a novel sansalvamide A analogue on growth, cell-cycle phases, and induction of apoptosis in human pancreatic cancer cells in vitro. The sansalvamide analogue caused marked time- and concentration-dependent inhibition of DNA synthesis and cell proliferation of two human pancreatic cancer cell lines (AsPC-1 and S2-013). The analogue induced G0/G1 phase cell-cycle arrest and morphological changes suggesting induction of apoptosis. Apoptosis was confirmed by annexin V binding. This novel sansalvamide analogue inhibits growth of pancreatic cancer cells through G0/G1 arrest and induces apoptosis. Sansalvamide analogues may be valuable for the treatment of pancreatic cancer

  13. 99mTc-HYNIC-TNF analogues (WH701) derived from phage display peptide libraries for imaging TNF-receptor-positive ovarian carcinoma: Preclinical evaluation

    International Nuclear Information System (INIS)

    Xia, J.S.; Wu, H.; Xiang, Y.; Xia, T.; Li, H.

    2002-01-01

    Aim: In this investigation, 99m Tc-hydrazinonicotinyl-TNF analogs (WH701) was labeled using ethylenediaminediacetic acid (EDDA) as coligand(A number of TNF analogs had been selected and synthesized using random phage-display peptides library in our lab ) and Pharmacokinetics and feasibility studies were performed for its potential use as diagnostic radiopharmaceutical. Material and Methods: The peptide was radiolabeled with 99mTc using HYNIC as a bifunctional chelator and EDDA as coligand. The complexes were characterized by HPLC. The in vitro stability of the radiolabeled peptide WH701 in serum and in phosphate buffer were examined simultaneity. Biodistribution studies were conducted to determine the in vivo characteristics of the complexes. The tumor uptake and image were also conducted in HOC8 tumor-bearing nude mice. Results: The peptide analog permitted efficient incorporation of 99mTc. The preparation of 99mTc-WH701 was stable in vitro. HPLC analysis of the urine samples collected after injection of 99mTc-WH701 showed that the radioactivity elution profile and Rt of the peak were similar to those of the preparation injected. Studies in vivo suggested that the biological activity of the peptide was not compromised. The agent cleared rapidly from the blood. The labeled peptide was shown in the mouse model to localize rapidly and specifically in site of tumor. Images of diagnostic quality could be obtained within 30 min post-administration in all studies. Conclusion: The TNF analogue peptide WH701 can be radiolabeled with 99mTc by HYNIC using EDDA as coligand without loss of affinity, and the 99mTc -WH701 is not degraded in serum and shows radiochemical stability for an extended period of time in vitro. The high specific tumor uptake, rapid blood clearance, and predominantly renal excretion make 99mTc -WH701 a promising candidate for tumor imaging. This agent is worthy of further investigation

  14. Structure-activity studies of RFamide peptides reveal subtype-selective activation of neuropeptide FF1 and FF2 receptors.

    Science.gov (United States)

    Findeisen, Maria; Rathmann, Daniel; Beck-Sickinger, Annette G

    2011-06-06

    Selectivity is a major issue in closely related multiligand/multireceptor systems. In this study we investigated the RFamide systems of hNPFF₁R and hNPFF₂R that bind the endogenous peptide hormones NPFF, NPAF, NPVF, and NPSF. By use of a systematic approach, we characterized the role of the C-terminal dipeptide with respect to agonistic properties using synthesized [Xaa 7]NPFF and [Xaa 8]NPFF analogues. We were able to identify only slight differences in potency upon changing the position of Arg 7, as all modifications resulted in identical behavior at the NPFF₁R and NPFF₂R. However, the C-terminal Phe 8 was able to be replaced by Trp or His with only a minor loss in potency at the NPFF₂R relative to the NPFF₁R. Analogues with shorter side chains, such as α-amino-4-guanidino butyric acid ([Agb 7]NPFF) or phenylglycine ([Phg 8]NPFF), decreased efficacy for the NPFF₁ R to 25-31 % of the maximal response, suggesting that these agonist-receptor complexes are more susceptible to structural modifications. In contrast, mutations to the conserved Asp 6.59 residue in the third extracellular loop of both receptors revealed a higher sensitivity toward the hNPFF₂R receptor than toward hNPFF₁R. These data provide new insight into the subtype-specific agonistic activation of the NPFF₁ and NPFF(2) receptors that are necessary for the development of selective agonists. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. In vitro Evaluation of a Bombesin Antagonistic Analogue Conjugated with DOTA-Ala(SO{sub 3}H)-Aminooctanoyl for Targeting of the Gastrin-releasing Peptide Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jae Cheong; Cho, Eun Ha; Kim, Jin Joo; Lee, So Young; Choi, Sang Mu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    As Bombesin (BBS) binds with high affinity to GRPR, BBS derivatives have been labeled with various radionuclides such as {sup 99}mTc, {sup 111}In, {sup 90}Y, {sup 64}Cu, {sup 177}Lu, {sup 68}Ga, or {sup 18}F and have proved to be successful candidates for peptide receptor radiotherapy (PRRT). In this study, we employed Ala(SO{sub 3}H)-Aminooctanoyl as a linker of BBS antagonistic peptide sequence, Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-NH{sub 2}, with DOTA to prepare radiolabeled candidates for GRPR targeting. A DOTA-conjugated BBS antagonistic analogue was synthesized and radiolabeled with {sup 177}Lu, and in vitro characteristics on GRPR-overexpressing human prostate tumor cells were evaluated. In conclusion, a novel BBS antagonistic analogue, {sup 177}Lu-DOTA-sBBNA, is a promising candidate for the targeting of GRPR-over-expressing tumors. Further investigations to evaluate its in vivo characteristics and therapeutic efficacy are needed.

  16. Peptide profiling of bovine kefir reveals 236 unique peptides released from caseins during its production by starter culture or kefir grains.

    Science.gov (United States)

    Ebner, Jennifer; Aşçı Arslan, Ayşe; Fedorova, Maria; Hoffmann, Ralf; Küçükçetin, Ahmet; Pischetsrieder, Monika

    2015-03-18

    composition of the peptide profile can be controlled by the applied microflora (grains or starter culture). On the other hand, a considerable portion of the peptide profile was identified to be typical for kefir in general and independent from production parameters. In summary, the generated kefir peptide profile helped to reveal its origin and to identify bioactive peptides in kefir, which may advance the understanding of health benefits of this food product. The results further indicate that subsets of the kefir peptide list can be used as markers to control food authenticity, for example, to distinguish different types of kefir. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Comparative mode of action of novel hybrid peptide CS-1a and its rearranged amphipathic analogue CS-2a.

    Science.gov (United States)

    Joshi, Seema; Bisht, Gopal S; Rawat, Diwan S; Maiti, Souvik; Pasha, Santosh

    2012-10-01

    Cell selective, naturally occurring, host defence cationic peptides present a good template for the design of novel peptides with the aim of achieving a short length with improved antimicrobial potency and selectivity. A novel, short peptide CS-1a (14 residues) was derived using a sequence hybridization approach on sarcotoxin I (39 residues) and cecropin B (35 residues). The sequence of CS-1a was rearranged to enhance amphipathicity with the help of a Schiffer-Edmundson diagram to obtain CS-2a. Both peptides showed good antibacterial activity in the concentration range 4-16 μg·mL(-1) against susceptible as well as drug-resistant bacterial strains, including the clinically relevant pathogens Acenatobacter sp. and methicillin-resistant Staphylococcus aureus. The major thrust of these peptides is their nonhaemolytic activity against human red blood cells up to a high concentration of 512 μg·mL(-1). Compared to CS-1a, amphipathic peptide CS-2a showed a more pronounced α-helical conformation, along with a better membrane insertion depth in bacterial mimic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) small unilamellar vesicles. With equivalent lipid-binding affinity, the two peptides assumed different pathways of membrane disruption, as demonstrated by calcein leakage and the results of transmission electron microscopy on model bacterial mimic large unilamellar vesicles. Extending the work from model membranes to intact Escherichia coli cells, differences in membrane perturbation were visible in microscopic images of peptide-treated E. coli. The present study describes two novel short peptides with potent activity, cell selectivity and divergent modes of action that will aid in the future design of peptides with better therapeutic potential. © 2012 The Authors Journal compilation © 2012 FEBS.

  18. Studies on lactoferricin-derived Escherichia coli membrane-active peptides reveal differences in the mechanism of N-acylated versus nonacylated peptides.

    Science.gov (United States)

    Zweytick, Dagmar; Deutsch, Günter; Andrä, Jörg; Blondelle, Sylvie E; Vollmer, Ekkehard; Jerala, Roman; Lohner, Karl

    2011-06-17

    To improve the low antimicrobial activity of LF11, an 11-mer peptide derived from human lactoferricin, mutant sequences were designed based on the defined structure of LF11 in the lipidic environment. Thus, deletion of noncharged polar residues and strengthening of the hydrophobic N-terminal part upon adding a bulky hydrophobic amino acid or N-acylation resulted in enhanced antimicrobial activity against Escherichia coli, which correlated with the peptides' degree of perturbation of bacterial membrane mimics. Nonacylated and N-acylated peptides exhibited different effects at a molecular level. Nonacylated peptides induced segregation of peptide-enriched and peptide-poor lipid domains in negatively charged bilayers, although N-acylated peptides formed small heterogeneous domains resulting in a higher degree of packing defects. Additionally, only N-acylated peptides perturbed the lateral packing of neutral lipids and exhibited increased permeability of E. coli lipid vesicles. The latter did not correlate with the extent of improvement of the antimicrobial activity, which could be explained by the fact that elevated binding of N-acylated peptides to lipopolysaccharides of the outer membrane of gram-negative bacteria seems to counteract the elevated membrane permeabilization, reflected in the respective minimal inhibitory concentration for E. coli. The antimicrobial activity of the peptides correlated with an increase of membrane curvature stress and hence bilayer instability. Transmission electron microscopy revealed that only the N-acylated peptides induced tubular protrusions from the outer membrane, whereas all peptides caused detachment of the outer and inner membrane of E. coli bacteria. Viability tests demonstrated that these bacteria were dead before onset of visible cell lysis.

  19. Studies on Lactoferricin-derived Escherichia coli Membrane-active Peptides Reveal Differences in the Mechanism of N-Acylated Versus Nonacylated Peptides*

    Science.gov (United States)

    Zweytick, Dagmar; Deutsch, Günter; Andrä, Jörg; Blondelle, Sylvie E.; Vollmer, Ekkehard; Jerala, Roman; Lohner, Karl

    2011-01-01

    To improve the low antimicrobial activity of LF11, an 11-mer peptide derived from human lactoferricin, mutant sequences were designed based on the defined structure of LF11 in the lipidic environment. Thus, deletion of noncharged polar residues and strengthening of the hydrophobic N-terminal part upon adding a bulky hydrophobic amino acid or N-acylation resulted in enhanced antimicrobial activity against Escherichia coli, which correlated with the peptides' degree of perturbation of bacterial membrane mimics. Nonacylated and N-acylated peptides exhibited different effects at a molecular level. Nonacylated peptides induced segregation of peptide-enriched and peptide-poor lipid domains in negatively charged bilayers, although N-acylated peptides formed small heterogeneous domains resulting in a higher degree of packing defects. Additionally, only N-acylated peptides perturbed the lateral packing of neutral lipids and exhibited increased permeability of E. coli lipid vesicles. The latter did not correlate with the extent of improvement of the antimicrobial activity, which could be explained by the fact that elevated binding of N-acylated peptides to lipopolysaccharides of the outer membrane of Gram-negative bacteria seems to counteract the elevated membrane permeabilization, reflected in the respective minimal inhibitory concentration for E. coli. The antimicrobial activity of the peptides correlated with an increase of membrane curvature stress and hence bilayer instability. Transmission electron microscopy revealed that only the N-acylated peptides induced tubular protrusions from the outer membrane, whereas all peptides caused detachment of the outer and inner membrane of E. coli bacteria. Viability tests demonstrated that these bacteria were dead before onset of visible cell lysis. PMID:21515687

  20. Synthesis and Pharmacology of Halogenated δ-Opioid-Selective [D-Ala2]Deltorphin II Peptide Analogues

    Science.gov (United States)

    Pescatore, Robyn; Marrone, Gina F.; Sedberry, Seth; Vinton, Daniel; Finkelstein, Netanel; Katlowitz, Yitzchak E.; Pasternak, Gavril W.; Wilson, Krista R.; Majumdar, Susruta

    2015-01-01

    Deltorphins are naturally occurring peptides produced by the skin of the giant monkey frog (Phyllomedusa bicolor). They are δ-opioid receptor-selective agonists. Herein, we report the design and synthesis of a peptide, Tyr-D-Ala-(pI)Phe-Glu-Ile-Ile-Gly-NH2 3 (GATE3-8), based on the [D-Ala2]deltorphin II template, which is δ-selective in in vitro radioligand binding assays over the μ- and κ-opioid receptors. It is a full agonist in [35S]GTPγS functional assays and analgesic when administered supraspinally to mice. Analgesia of 3 (GATE3-8) is blocked by the selective δ receptor antagonist naltrindole, indicating that the analgesic action of 3 is mediated by the δ-opioid receptor. We have established a radioligand in which 125I isincorporated into 3 (GATE3-8). The radioligand has a KD of 0.1 nM in Chinese hamster ovary (CHO) cells expressing the δ receptor. Additionally, a series of peptides based on 3 (GATE3-8) was synthesized by incorporating various halogens in the para position on the aromatic ring of Phe3. The peptides were characterized for binding affinity at the μ-, δ-, and κ-opioid receptors, which showed a linear correlation between binding affinity and the size of the halogen substituent. These peptides may be interesting tools for probing δ-opioid receptor pharmacology. PMID:25844930

  1. Synthesis and pharmacology of halogenated δ-opioid-selective [d-Ala(2)]deltorphin II peptide analogues.

    Science.gov (United States)

    Pescatore, Robyn; Marrone, Gina F; Sedberry, Seth; Vinton, Daniel; Finkelstein, Netanel; Katlowitz, Yitzchak E; Pasternak, Gavril W; Wilson, Krista R; Majumdar, Susruta

    2015-06-17

    Deltorphins are naturally occurring peptides produced by the skin of the giant monkey frog (Phyllomedusa bicolor). They are δ-opioid receptor-selective agonists. Herein, we report the design and synthesis of a peptide, Tyr-d-Ala-(pI)Phe-Glu-Ile-Ile-Gly-NH2 3 (GATE3-8), based on the [d-Ala(2)]deltorphin II template, which is δ-selective in in vitro radioligand binding assays over the μ- and κ-opioid receptors. It is a full agonist in [(35)S]GTPγS functional assays and analgesic when administered supraspinally to mice. Analgesia of 3 (GATE3-8) is blocked by the selective δ receptor antagonist naltrindole, indicating that the analgesic action of 3 is mediated by the δ-opioid receptor. We have established a radioligand in which (125)I is incorporated into 3 (GATE3-8). The radioligand has a KD of 0.1 nM in Chinese hamster ovary (CHO) cells expressing the δ receptor. Additionally, a series of peptides based on 3 (GATE3-8) was synthesized by incorporating various halogens in the para position on the aromatic ring of Phe(3). The peptides were characterized for binding affinity at the μ-, δ-, and κ-opioid receptors, which showed a linear correlation between binding affinity and the size of the halogen substituent. These peptides may be interesting tools for probing δ-opioid receptor pharmacology.

  2. Thermodynamic description of polymorphism in Q- and N-rich peptide aggregates revealed by atomistic simulation.

    Science.gov (United States)

    Berryman, Joshua T; Radford, Sheena E; Harris, Sarah A

    2009-07-08

    Amyloid fibrils are long, helically symmetric protein aggregates that can display substantial variation (polymorphism), including alterations in twist and structure at the beta-strand and protofilament levels, even when grown under the same experimental conditions. The structural and thermodynamic origins of this behavior are not yet understood. We performed molecular-dynamics simulations to determine the thermodynamic properties of different polymorphs of the peptide GNNQQNY, modeling fibrils containing different numbers of protofilaments based on the structure of amyloid-like cross-beta crystals of this peptide. We also modeled fibrils with new orientations of the side chains, as well as a de novo designed structure based on antiparallel beta-strands. The simulations show that these polymorphs are approximately isoenergetic under a range of conditions. Structural analysis reveals a dynamic reorganization of electrostatics and hydrogen bonding in the main and side chains of the Gln and Asn residues that characterize this peptide sequence. Q/N-rich stretches are found in several amyloidogenic proteins and peptides, including the yeast prions Sup35-N and Ure2p, as well as in the human poly-Q disease proteins, including the ataxins and huntingtin. Based on our results, we propose that these residues imbue a unique structural plasticity to the amyloid fibrils that they comprise, rationalizing the ability of proteins enriched in these amino acids to form prion strains with heritable and different phenotypic traits.

  3. Effect of liraglutide, a glucagon-like peptide-1 analogue, on left ventricular function in stable chronic heart failure patients with and without diabetes (LIVE)

    DEFF Research Database (Denmark)

    Jorsal, Anders; Kistorp, Caroline Micheala Nervil; Holmager, Pernille

    2017-01-01

    trial. Patients (n = 241) with reduced left ventricular ejection fraction (LVEF ≤45%) were recruited (February 2012 to August 2015). Patients were clinically stable and on optimal heart failure treatment. Intervention was liraglutide 1.8 mg once daily or matching placebo for 24 weeks. The LVEF...... with and without diabetes. Treatment with liraglutide was associated with an increase in heart rate and more serious cardiac adverse events, and this raises some concern with respect to the use of liraglutide in patients with chronic heart failure and reduced left ventricular function. More data on the safety......AIMS: To determine the effect of the glucagon-like peptide-1 analogue liraglutide on left ventricular function in chronic heart failure patients with and without type 2 diabetes. METHODS AND RESULTS: LIVE was an investigator-initiated, randomised, double-blinded, placebo-controlled multicentre...

  4. Identification of ischemia-regulated phosphorylation sites in connexin43: A possible target for the antiarrhythmic peptide analogue rotigaptide (ZP123)

    DEFF Research Database (Denmark)

    Axelsen, Lene Nygaard; Stahlhut, Martin; Mohammed, Shabaz

    2006-01-01

    Previous studies suggest that dephosphorylation of connexin43 (Cx43) is related to uncoupling of gap junction communication, which plays an important role in the genesis of ischemia-induced ventricular tachycardia. We studied changes in Cx43 phosphorylation during global ischemia in the absence...... and presence of the antiarrhythmic peptide analogue rotigaptide (formerly known as ZP123). Phosphorylation analysis was performed on Cx43 purified from isolated perfused rat hearts using matrix-assisted laser desorption/ionization mass spectrometry and liquid chromatography electrospray ionization tandem mass...... of ischemia, the critical time interval where gap junction uncoupling occurs, Ser297 and Ser368 also became fully dephosphorylated. During the same time period, all untreated hearts developed asystole. Treatment with rotigaptide significantly increased the time to ischemia-induced asystole and suppressed...

  5. Synthetic Peptides Analogue to Enamel Proteins Promote Osteogenic Differentiation of MC3T3-E1 and Mesenchymal Stem Cells

    Czech Academy of Sciences Publication Activity Database

    Rubert, M.; Ramis, J. M.; Vondrášek, Jiří; Gaya, A.; Lyngstadaas, S. P.; Monjo, M.

    2011-01-01

    Roč. 1, č. 2 (2011), s. 198-209 ISSN 2157-9083 Grant - others:GA ČR(CZ) GAP302/10/0427 Institutional research plan: CEZ:AV0Z40550506 Keywords : proline-rich regions * synthetic peptides * bone formation * mineralization * In Vitro Subject RIV: EI - Biotechnology ; Bionics

  6. Glucagon-like peptide-1 analogue therapy for psoriasis patients with obesity and type 2 diabetes: a prospective cohort study.

    LENUS (Irish Health Repository)

    Ahern, T

    2012-06-13

    Background  Diabetes and obesity are more prevalent amongst psoriasis patients as is disturbance of the innate immune system. GLP-1 analogue therapy considerably improves weight and glycaemic control in people with type 2 diabetes and its receptor is present on innate immune cells. Objective  We aimed to determine the effect of liraglutide, a GLP-1 analogue, on psoriasis severity. Methods  Before and after 10 weeks of liraglutide therapy (1.2 mg subcutaneously daily) we determined the psoriasis area and severity index (PASI) and the dermatology life quality index (DLQI) in seven people with both psoriasis and diabetes (median age 48 years, median body mass index 48.2 kg\\/m(2) ). We also evaluated the immunomodulatory properties of liraglutide by measuring circulating lymphocyte subset numbers and monocyte cytokine production. Results  Liraglutide therapy decreased the median PASI from 4.8 to 3.0 (P = 0.03) and the median DLQI from 6.0 to 2.0 (P = 0.03). Weight and glycaemic control improved significantly. Circulating invariant natural killer T (iNKT) cells increased from 0.13% of T lymphocytes to 0.40% (P = 0.03). Liraglutide therapy also effected a non-significant 54% decrease in the proportion of circulating monocytes that produced tumour necrosis factor alpha (P = 0.07). Conclusion  GLP-1 analogue therapy improves psoriasis severity, increases circulating iNKT cell number and modulates monocyte cytokine secretion. These effects may result from improvements in weight and glycaemic control as well as from direct immune effects of GLP-1 receptor activation. Prospective controlled trials of GLP-1 therapies are warranted, across all weight groups, in psoriasis patients with and without type 2 diabetes.

  7. GLP-1 and exendin-4 for imaging endocrine pancreas. A review. Labelled glucagon-like peptide-1 analogues: past, present and future

    International Nuclear Information System (INIS)

    Hubalewska-Dydejczyk, A.; Sowa-Staszczak, A.; Tomaszuk, M.; Stefańska, A.

    2015-01-01

    Glucagon-like peptide 1 (GLP-1) receptors expression has been found on many types of cancer cells. In case of benign insulinoma the density of those receptors is even higher than the density of somatostatin receptors. This article presents the results of clinical trials proving the utility of GLP-1 receptors imaging. Scintigraphy or positron emission tomography with the use of GLP-1 analogues labelled with appropriate radioisotopes ( 111I n, 99m Tc, 68 Ga, 18 F or 64 Cu) seem to be superior compared with other available techniques in diagnosis of hardly detectable benign insulinoma. While surgery is the only effective therapy for insulinoma patients, therefore proper preoperative localization of the tumor allows sparing operation. Glucagon-like peptide 1 receptors might become also a target for imaging of other tumors such as gastrinoma, pheochromocytoma and medullary thyroid cancer (MTC), which also were shown to over express this type of receptors. However, studies with larger groups of patients are required to prove the clinical usefulness of this indication. Moreover GLP-1 receptor imaging seems to be a potential tool to evaluate pancreatic beta cell mass (BCM). It may be useful in the early diagnosis of beta cell loss in preclinical phases of diabetes. The panceratic beta cells imaging may influence the prophylaxis of diabetes and management of diabetic patients. Presented results of clinical trials prove that glucagon-like peptide 1 receptor imaging might become helpful diagnostic strategy particularly in case of patients with benign insulinoma tumors, but also patients with gastrinoma, pheochromocytoma, medullary thyroid cancer and diabetes.

  8. Preclinical evaluation of "1"1"1In-DOTA-Bombesin analogue for peptide receptor targeted imaging

    International Nuclear Information System (INIS)

    Salgueiro, C.; Castiglia, S.G. de; Tesan, F.; Salgueiro, M.J.

    2017-01-01

    Peptide receptors are very important targets for imaging and therapy. The bombesin family is becoming significant, in special the gastrine-releasing peptide receptor (GRPr) that has been found in Prostate and Breast tumors. The aim of this work is to label [DOTA-Pro1,Tyr4] BN with "1"1"1InCl3 and study its efficacy in normal and tumor animals. Radiolabeling experiences were made to find the best peptide : radionuclide relationship. The radiochemical purity was determined by Sep-pak C18 cartridge (Waters) and ITLC-SG using 50mM EDTA in 0.1M ammonium acetate (pH 5.5) and 3.5%(v/v) ammonia/methanol 1:1. Gamma imaging studies were made 24 hs after injection of the product in control rats. On the other hand gamma imaging studies were made at 24 hs in tumor bearing nude mice too. The tumor was induced by subcutaneous injection of PC3 cells. For biodistribution studies animals were sacrificed and blood, pancreas, intestine, kidneys, liver, lungs, femoral muscle and tumor were analyzed. The results were expressed as %ID/g of tissue. Radiolabeling experiments allowed us to obtain an stable product with >95% of radiochemical purity and 5.78MBq/nmol of specific activity, with a ratio of 13μg peptide per In-111 mCi. The normal and tumor animals imaging show physiological uptake in kidneys and a biodistribution according to bibliography. A specific uptake is evidenced in tumor. Our results show a radiochemical stable compound for 48 hs and suitable for GRPr imaging. (authors) [es

  9. Revealing Television's Analogue Heroes

    NARCIS (Netherlands)

    Jackson, Vanessa

    2013-01-01

    abstractIn this article I will argue that we need to create new archival models in order to preserve and share knowledge of historical, ‘hidden’ television professions and production cultures. Oral history traditions of recording life stories give us a useful starting point. Engineering ‘encounters’

  10. Atomic force microscopy of bacteria reveals the mechanobiology of pore forming peptide action.

    Science.gov (United States)

    Mularski, Anna; Wilksch, Jonathan J; Hanssen, Eric; Strugnell, Richard A; Separovic, Frances

    2016-06-01

    Time-resolved AFM images revealed that the antimicrobial peptide (AMP) caerin 1.1 caused localised defects in the cell walls of lysed Klebsiella pneumoniae cells, corroborating a pore-forming mechanism of action. The defects continued to grow during the AFM experiment, in corroboration with large holes that were visualised by scanning electron microscopy. Defects in cytoplasmic membranes were visualised by cryo-EM using the same peptide concentration as in the AFM experiments. At three times the minimum inhibitory concentration of caerin, 'pores' were apparent in the outer membrane. The capsule of K. pneumoniae AJ218 was unchanged by exposure to caerin, indicating that the ionic interaction of the positively charged peptide with the negatively charged capsular polysaccharide is not a critical component of AMP interaction with K. pneumoniae AJ218 cells. Further, the presence of a capsule confers no advantage to wild-type over capsule-deficient cells when exposed to the AMP caerin. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Effect of glucagon-like peptide-1 analogue; Exendin-4, on cognitive functions in type 2 diabetes mellitus; possible modulation of brain derived neurotrophic factor and brain Visfatin.

    Science.gov (United States)

    Abdelwahed, O M; Tork, O M; Gamal El Din, M M; Rashed, L; Zickri, M

    2018-02-05

    Brain derived neurotrophic factor (BDNF) is one of the most essential neurotrophic factors in the brain. BDNF is involved in learning, memory and locomotion suggesting it as a target in type 2 diabetes mellitus (T2DM) associated cognitive changes. Visfatin; an adipokine discovered to be expressed in the brain; was found to have multiple effects including its participation in keeping energy supply to the cell and is consequentially involved in cell survival. Its role in cognitive functions in T2DM was not studied before. Recent studies point to the possible neuro-protective mechanisms of glucagon-like peptide 1 analogue: Exendin-4 (Ex-4) in many cognitive disorders, but whether BDNF or Visfatin are involved or not in its neuro-protective mechanisms; is still unknown. to study the changes in cognitive functions in T2DM, either not treated or treated with Glucagon-like peptide 1 (GLP-1) analogue: Ex-4, and to identify the possible underlying mechanisms of these changes and whether BDNF and brain Visfatin are involved. A total of 36 adult male wistar albino rats were divided into 4 groups; Control, Exendin-4 control, Diabetic and Exendin-4 treated groups. At the end of the study, Y-maze and open field tests were done the day before scarification to assess spatial working memory and locomotion, respectively. Fasting glucose and insulin, lipid profile and tumor necrosis factor- alpha (TNF-α) were measured in the serum. Homeostasis model assessment insulin resistance was calculated. In the brain tissue, malondialdehyde (MDA) level, gene expression and protein levels of BDNF and Visfatin, area of degenerated neurons, area of glial cells and area % of synaptophysin immunoexpression were assessed. Compared with the control, the untreated diabetic rats showed insulin resistance, dyslipidemia and elevation of serum TNF-α. The brain tissue showed down-regulation of BDNF gene expression and reduction of its protein level, up-regulation of Visfatin gene expression and elevation

  12. Reducing renal uptake of 9Y- and 177Lu-labeled alpha-melanocyte stimulating hormone peptide analogues

    International Nuclear Information System (INIS)

    Miao Yubin; Fisher, Darrell R.; Quinn, Thomas P.

    2006-01-01

    Objective: The purpose of this study was to improve the tumor-to-kidney uptake ratios of 9 Y- and 177 Lu-[1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-Re-Cys 3,4,1 , D-Phe 7 , Arg 11 ]α-melanocyte stimulating hormone 3-13 {DOTA-Re(Arg 11 )CCMSH} through coupling a negatively charged glutamic acid (Glu) to the peptide sequence. Methods: A new peptide of DOTA-Re(Glu 2 , Arg 11 )CCMSH was designed, synthesized and labeled with 9 Y and 177 Lu. Pharmacokinetics of 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH was determined in B16/F1 murine melanoma-bearing C57 mice. Results: 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH exhibited significantly (P 9 Y- and 177 Lu-DOTA-Re(Arg 11 )CCMSH at 30 min and at 2, 4 and 24 h after dose administration. The renal uptake values of 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH were 28.16% and 28.81% of those of 9 Y- and 177 Lu-DOTA-Re(Arg 11 )CCMSH, respectively, at 4 h postinjection. 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH displayed higher tumor-to-kidney uptake ratios than 9 Y- and 177 Lu-DOTA-Re(Arg 11 )CCMSH at 30 min and at 2, 4 and 24 h after dose administration. The tumor-to-kidney uptake ratio of 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH was 2.28 and 1.69 times of 9 Y- and 177 Lu-DOTA-Re(Arg 11 )CCMSH, respectively, at 4 h postinjection. The 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH activity accumulation was low in normal organs except for kidney. Conclusions: Coupling a negatively charged amino acid (Glu) to the CCMSH peptide sequence dramatically reduced the renal uptake values and increased the tumor-to-kidney uptake ratios of 9 Y- and 177 Lu-DOTA-Re(Glu 2 , Arg 11 )CCMSH, facilitating their potential applications as radiopharmaceuticals for targeted radionuclide therapy of melanoma

  13. Structural, Biochemical, and Computational Studies Reveal the Mechanism of Selective Aldehyde Dehydrogenase 1A1 Inhibition by Cytotoxic Duocarmycin Analogues.

    Science.gov (United States)

    Koch, Maximilian F; Harteis, Sabrina; Blank, Iris D; Pestel, Galina; Tietze, Lutz F; Ochsenfeld, Christian; Schneider, Sabine; Sieber, Stephan A

    2015-11-09

    Analogues of the natural product duocarmycin bearing an indole moiety were shown to bind aldehyde dehydrogenase 1A1 (ALDH1A1) in addition to DNA, while derivatives without the indole solely addressed the ALDH1A1 protein. The molecular mechanism of selective ALDH1A1 inhibition by duocarmycin analogues was unraveled through cocrystallization, mutational studies, and molecular dynamics simulations. The structure of the complex shows the compound embedded in a hydrophobic pocket, where it is stabilized by several crucial π-stacking and van der Waals interactions. This binding mode positions the cyclopropyl electrophile for nucleophilic attack by the noncatalytic residue Cys302, thereby resulting in covalent attachment, steric occlusion of the active site, and inhibition of catalysis. The selectivity of duocarmycin analogues for ALDH1A1 is unique, since only minor alterations in the sequence of closely related protein isoforms restrict compound accessibility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Comparison at the peptide level with post-translational modification consideration reveals more differences between two unenriched samples.

    Science.gov (United States)

    Yin, Jianrui; Shao, Chen; Jia, Lulu; Gao, Youhe

    2014-06-30

    In shotgun strategies, peptide sequences are first identified from tandem mass (MS/MS) spectra, and the existence and abundance of the proteins are then inferred from the peptide information. However, the protein inference step can produce errors and a loss of information. To identify the information that is lost using the traditional approaches, this study compared the proteomic data of two leukemia cell lines (Jurkat and K562) at the peptide level with consideration of post-translational modifications (PTMs). The raw files from the two cell lines were searched against the decoy IPI-human database version 3.68, which contains forward and reverse sequences. Then the observed modification name in the results was matched with the modification classification on the Unimod website by a manual search. Only the peptides with 'post-translational' modifications were compared between the two cell lines. After searching the database with consideration of PTMs, a total of 44046 non-redundant peptides were identified in both the Jurkat and K562 cell lines. Of these peptides, even without specific PTM enrichment, 11.43% of them (with at least two spectra in one cell line) existed in different PTM forms between the two cell lines, and 1.73% of the peptides were modified in both cell lines, but with different modifications or possibly on different sites. Comparing proteomic data at the peptide level with consideration of PTMs can reveal more differences between two unenriched samples. Copyright © 2014 John Wiley & Sons, Ltd.

  15. The Potential Use of Natural and Structural Analogues of Antimicrobial Peptides in the Fight against Neglected Tropical Diseases

    Directory of Open Access Journals (Sweden)

    Lewies Angélique

    2015-08-01

    Full Text Available Recently, research into the development of new antimicrobial agents has been driven by the increase in resistance to traditional antibiotics and Emerging Infectious Diseases. Antimicrobial peptides (AMPs are promising candidates as alternatives to current antibiotics in the treatment and prevention of microbial infections. AMPs are produced by all known living species, displaying direct antimicrobial killing activity and playing an important role in innate immunity. To date, more than 2000 AMPs have been discovered and many of these exhibit broad-spectrum antibacterial, antiviral and anti-parasitic activity. Neglected tropical diseases (NTDs are caused by a variety of pathogens and are particularly wide-spread in low-income and developing regions of the world. Alternative, cost effective treatments are desperately needed to effectively battle these medically diverse diseases. AMPs have been shown to be effective against a variety of NTDs, including African trypanosomes, leishmaniosis and Chagas disease, trachoma and leprosy. In this review, the potential of selected AMPs to successfully treat a variety of NTD infections will be critically evaluated.

  16. SANDPUMA: ensemble predictions of nonribosomal peptide chemistry reveal biosynthetic diversity across Actinobacteria

    NARCIS (Netherlands)

    Chevrette, Marc G.; Aicheler, Fabian; Kohlbacher, Oliver; Currie, Cameron R.; Medema, M.H.

    2017-01-01

    Nonribosomally synthesized peptides (NRPs) are natural products with widespread applications in medicine and biotechnology. Many algorithms have been developed to predict the substrate specificities of nonribosomal peptide synthetase adenylation (A) domains from DNA sequences, which enables

  17. ACTINOMYCIN D ANALOGUES

    DEFF Research Database (Denmark)

    1997-01-01

    The present invention relates to new compounds being structurally and functionally similar to Actinomycin D and to combinatorial libraries of such compounds. The Actinomycin D analogues according to the present invention comprise two linear or cyclic peptide moieties constituted by $g...

  18. Glucagon-like peptide-1 analogue, liraglutide, delays onset and reduces severity of experimental autoimmune encephalitis in Lewis rats

    Directory of Open Access Journals (Sweden)

    Brian DellaValle

    2016-11-01

    Full Text Available AbstractIntroduction: Recent findings indicate that metabolic disturbances are involved in multiple sclerosis (MS pathology and influence the susceptibility to treatment, directing attention towards anti-diabetic drugs such as metformin and pioglitazone. Liraglutide, a drug of the glucagon-like peptide-1 (GLP-1 family, is also anti-diabetic and weight-reducing and is moreover, directly neuroprotective and anti-inflammatory in a broad spectrum of experimental models of brain disease. In this study we investigate the potential for this FDA-approved drug, liraglutide, as a treatment for MS by utilizing the experimental model, experimental autoimmune encephalitis (EAE.Methods: EAE was induced in 30 female Lewis rats that subsequently received twice-daily liraglutide (200 µg/kg s.c. or saline. Healthy controls were included (saline, n=6, liraglutide, n=7. Clinical score and weight were assessed daily by blinded observers. Animals were killed at peak disease severity (day 11 or if exceeding humane endpoint (clinical score ≥4. Protein levels of manganese superoxide dismutase (MnSOD, amyloid precursor protein (APP, and glial fibrillary acidic protein (GFAP were determined.Results: Liraglutide treatment delayed disease onset (group clinical score significantly >0 by two days and markedly reduced disease severity (median clinical score 2 vs. 5; p=0.0003. Fourteen of 15 (93% of vehicle-treated rats reached the humane endpoint (clinical score ≥4 by day 11 compared to 5 of 15 (33% of liraglutide-treated rats (p=0.0004. Liraglutide substantially increased the mitochondrial antioxidant MnSOD (p<0.01 and reduced the neurodegenerative marker APP (p=0.036 in the brain. GFAP levels were not significantly changed with drug treatment (p=0.09Conclusion: We demonstrate, for the first time, that liraglutide treatment delays onset of EAE in Lewis rats and is associated with improved protective capacity against oxidative stress. These data suggest GLP-1 receptor

  19. Massively parallel amplicon sequencing reveals isotype-specific variability of antimicrobial peptide transcripts in Mytilus galloprovincialis.

    Directory of Open Access Journals (Sweden)

    Umberto Rosani

    Full Text Available BACKGROUND: Effective innate responses against potential pathogens are essential in the living world and possibly contributed to the evolutionary success of invertebrates. Taken together, antimicrobial peptide (AMP precursors of defensin, mytilin, myticin and mytimycin can represent about 40% of the hemocyte transcriptome in mussels injected with viral-like and bacterial preparations, and unique profiles of myticin C variants are expressed in single mussels. Based on amplicon pyrosequencing, we have ascertained and compared the natural and Vibrio-induced diversity of AMP transcripts in mussel hemocytes from three European regions. METHODOLOGY/PRINCIPAL FINDINGS: Hemolymph was collected from mussels farmed in the coastal regions of Palavas (France, Vigo (Spain and Venice (Italy. To represent the AMP families known in M. galloprovincialis, nine transcript sequences have been selected, amplified from hemocyte RNA and subjected to pyrosequencing. Hemolymph from farmed (offshore and wild (lagoon Venice mussels, both injected with 10(7 Vibrio cells, were similarly processed. Amplicon pyrosequencing emphasized the AMP transcript diversity, with Single Nucleotide Changes (SNC minimal for mytilin B/C and maximal for arthropod-like defensin and myticin C. Ratio of non-synonymous vs. synonymous changes also greatly differed between AMP isotypes. Overall, each amplicon revealed similar levels of nucleotidic variation across geographical regions, with two main sequence patterns confirmed for mytimycin and no substantial changes after immunostimulation. CONCLUSIONS/SIGNIFICANCE: Barcoding and bidirectional pyrosequencing allowed us to map and compare the transcript diversity of known mussel AMPs. Though most of the genuine cds variation was common to the analyzed samples we could estimate from 9 to 106 peptide variants in hemolymph pools representing 100 mussels, depending on the AMP isoform and sampling site. In this study, no prevailing SNC patterns related

  20. 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.

  1. Engineered jadomycin analogues with altered sugar moieties revealing JadS as a substrate flexible O-glycosyltransferase.

    Science.gov (United States)

    Li, Liyuan; Pan, Guohui; Zhu, Xifen; Fan, Keqiang; Gao, Wubin; Ai, Guomin; Ren, Jinwei; Shi, Mingxin; Olano, Carlos; Salas, José A; Yang, Keqian

    2017-07-01

    Glycosyltransferases (GTs)-mediated glycodiversification studies have drawn significant attention recently, with the goal of generating bioactive compounds with improved pharmacological properties by diversifying the appended sugars. The key to achieving glycodiversification is to identify natural and/or engineered flexible GTs capable of acting upon a broad range of substrates. Here, we report the use of a combinatorial biosynthetic approach to probe the substrate flexibility of JadS, the GT in jadomycin biosynthesis, towards different non-native NDP-sugar substrates, enabling us to identify six jadomycin B analogues with different sugar moieties. Further structural engineering by precursor-directed biosynthesis allowed us to obtain 11 new jadomycin analogues. Our results for the first time show that JadS is a flexible O-GT that can utilize both L- and D- sugars as donor substrates, and tolerate structural changes at the C2, C4 and C6 positions of the sugar moiety. JadS may be further exploited to generate novel glycosylated jadomycin molecules in future glycodiversification studies.

  2. Machine Learning Reveals a Non-Canonical Mode of Peptide Binding to MHC class II Molecules

    DEFF Research Database (Denmark)

    Andreatta, Massimo; Jurtz, Vanessa Isabell; Kaever, Thomas

    2017-01-01

    binding motif with a non-canonical binding core of length different from nine. This previously undescribed mode of peptide binding to MHCII molecules gives a more complete picture of peptide presentation by MHCII and allows us to model more accurately this event. This article is protected by copyright...

  3. A Novel α-Calcitonin Gene-Related Peptide Analogue Protects Against End-Organ Damage in Experimental Hypertension, Cardiac Hypertrophy and Heart Failure

    DEFF Research Database (Denmark)

    Aubdool, Aisah A; Thakore, Pratish; Argunhan, Fulye

    2017-01-01

    cardiovascular disease in two distinct murine models of hypertension and heart failure in vivoMethods -The ability of the αAnalogue to act selectively via the CGRP pathway was shown in skin using a CGRP receptor antagonist. The effect of the αAnalogue on Angiotensin II (AngII)-induced hypertension......, Western blot and histology. Results -The AngII-induced hypertension was attenuated by co-treatment with the αAnalogue (50nmol/kg/day, s.c., at a dose selected for lack of long term hypotensive effects at baseline). The αAnalogue protected against vascular, renal and cardiac dysfunction, characterised...... failure. It preserved heart function, assessed by echocardiography, whilst protecting against adverse cardiac remodelling and apoptosis. Moreover, treatment with the αAnalogue was well-tolerated with neither signs of desensitisation nor behavioural changes. Conclusions -These findings, in two distinct...

  4. Chemical probing of the human sirtuin 5 active site reveals its substrate acyl specificity and peptide-based inhibitors.

    Science.gov (United States)

    Roessler, Claudia; Nowak, Theresa; Pannek, Martin; Gertz, Melanie; Nguyen, Giang T T; Scharfe, Michael; Born, Ilona; Sippl, Wolfgang; Steegborn, Clemens; Schutkowski, Mike

    2014-09-26

    Sirtuins are NAD(+)-dependent deacetylases acting as sensors in metabolic pathways and stress response. In mammals there are seven isoforms. The mitochondrial sirtuin 5 is a weak deacetylase but a very efficient demalonylase and desuccinylase; however, its substrate acyl specificity has not been systematically analyzed. Herein, we investigated a carbamoyl phosphate synthetase 1 derived peptide substrate and modified the lysine side chain systematically to determine the acyl specificity of Sirt5. From that point we designed six potent peptide-based inhibitors that interact with the NAD(+) binding pocket. To characterize the interaction details causing the different substrate and inhibition properties we report several X-ray crystal structures of Sirt5 complexed with these peptides. Our results reveal the Sirt5 acyl selectivity and its molecular basis and enable the design of inhibitors for Sirt5. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Peptide Probes Reveal a Hydrophobic Steric Ratchet in the Anthrax Toxin Protective Antigen Translocase.

    Science.gov (United States)

    Colby, Jennifer M; Krantz, Bryan A

    2015-11-06

    Anthrax toxin is a tripartite virulence factor produced by Bacillus anthracis during infection. Under acidic endosomal pH conditions, the toxin's protective antigen (PA) component forms a transmembrane channel in host cells. The PA channel then translocates its two enzyme components, lethal factor and edema factor, into the host cytosol under the proton motive force. Protein translocation under a proton motive force is catalyzed by a series of nonspecific polypeptide binding sites, called clamps. A 10-residue guest/host peptide model system, KKKKKXXSXX, was used to functionally probe polypeptide-clamp interactions within wild-type PA channels. The guest residues were Thr, Ala, Leu, Phe, Tyr, and Trp. In steady-state translocation experiments, the channel blocked most tightly with peptides that had increasing amounts of nonpolar surface area. Cooperative peptide binding was observed in the Trp-containing peptide sequence but not the other tested sequences. Trp substitutions into a flexible, uncharged linker between the lethal factor amino-terminal domain and diphtheria toxin A chain expedited translocation. Therefore, peptide-clamp sites in translocase channels can sense large steric features (like tryptophan) in peptides, and while these steric interactions may make a peptide translocate poorly, in the context of folded domains, they can make the protein translocate more rapidly presumably via a hydrophobic steric ratchet mechanism. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Two-dimensional sum-frequency generation (2D SFG) reveals structure and dynamics of a surface-bound peptide

    Science.gov (United States)

    Laaser, Jennifer E.; Skoff, David R.; Ho, Jia-Jung; Joo, Yongho; Serrano, Arnaldo L.; Steinkruger, Jay D.; Gopalan, Padma; Gellman, Samuel H.; Zanni, Martin T.

    2014-01-01

    Surface-bound polypeptides and proteins are increasingly used to functionalize inorganic interfaces such as electrodes, but their structural characterization is exceedingly difficult with standard technologies. In this paper, we report the first two-dimensional sum-frequency generation (2D SFG) spectra of a peptide monolayer, which is collected by adding a mid-IR pulse shaper to a standard femtosecond SFG spectrometer. On a gold surface, standard FTIR spectroscopy is inconclusive about the peptide structure because of solvation-induced frequency shifts, but the 2D lineshapes, anharmonic shifts, and lifetimes obtained from 2D SFG reveal that the peptide is largely α-helical and upright. Random coil residues are also observed, which do not themselves appear in SFG spectra due to their isotropic structural distribution, but which still absorb infrared light and so can be detected by cross-peaks in 2D SFG spectra. We discuss these results in the context of peptide design. Because of the similar way in which the spectra are collected, these 2D SFG spectra can be directly compared to 2D IR spectra, thereby enabling structural interpretations of surface-bound peptides and biomolecules based on the well-studied structure/2D IR spectra relationships established from soluble proteins. PMID:24372101

  7. Molecular evolution of the neurohypophysial hormone precursors in mammals: Comparative genomics reveals novel mammalian oxytocin and vasopressin analogues.

    Science.gov (United States)

    Wallis, Michael

    2012-11-01

    Among vertebrates the neurohypophysial hormones show considerable variation. However, in eutherian mammals they have been considered rather conserved, with arginine vasopressin (AVP) and oxytocin (OT) in all species except pig and some relatives, where lysine vasopressin replaces AVP. The availability of genomic data for a wide range of mammals makes it possible to assess whether these peptides and their precursors may be more variable in Eutheria than previously suspected. A survey of these data confirms that AVP and OT occur in most eutherians, but with exceptions. In a New-World monkey (marmoset, Callithrix jacchus) and in tree shrew (Tupaia belangeri), Pro(8)OT replaces OT, confirming a recent report for these species. In armadillo (Dasypus novemcinctus) Leu(3)OT replaces OT, while in tenrec (Echinops telfairi) Thr(4)AVP replaces AVP. In these two species there is also evidence for additional genes/pseudogenes, encoding much-modified forms of AVP, but in most other eutherian species there is no evidence for additional neurohypophysial hormone genes. Evolutionary analysis shows that sequences of eutherian neurohypophysial hormone precursors are generally strongly conserved, particularly those regions encoding active peptide and neurophysin. The close association between OT and VP genes has led to frequent gene conversion of sequences encoding neurophysins. A monotreme, platypus (Ornithorhynchus anatinus) has genes for OT and AVP, organized tail-to-tail as in eutherians, but in marsupials 3-4 genes are present for neurohypophysial hormones, organized tail-to-head as in lower vertebrates. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumors: First comparative results using the somatostatin analogues Lu-177 DOTA-NOC and Lu-177 DOTA-TATE

    International Nuclear Information System (INIS)

    Wehrmann, C.; Senftleben, S.; Baum, R.P.

    2005-01-01

    Peptide receptor radionuclide therapy (PRRT) is used in our department since 5 years (approx. 400 applications) for the treatment of patients with metastatic neuroendocrine tumors. Of all known peptides, the somatostatin analogue DOTA-NOC shows in vitro the highest affinity to somatostatin receptors (sstr) 3 and 5 and a very high affinity to sstr 2. We studied the in vivo behaviour of the two peptides DOTA-NOC and DOTA-TATE (highest affinity to sstr 2) by the use of different parameters like tumor and organ uptake, effective half-lifes (kinetics) and mean absorbed organ and tumor doses. We studied 27 patients with metastatic neuroendocrine tumors with high somatostatin expression, as verified prior to treatment by Ga-68 DOTA-NOC receptor PET/CT or somatostatin receptor scintigraphy (Tc-99m EDDA-Hynic TOC or In-111 OctreoScan, planar and SPECT). 22 patients (8M and 14F; aged 619 years) were treated with 2500 6790 MBq Lu-177 DOTA-TATE. Another 5 patients (1M and 4F, aged 6310 years) were treated with 4000 7400 MBq Lu-177 DOTA-NOC. Labelling efficiency and radiochemical purity using Lutetium-177 chloride (obtained from PerkinElmer Life Sciences, USA) were constantly over 99.5%. Whole-body scans (anterior/posterior) were performed at 0.5h, 3h, 24h, 48h, 72h and 96h p.i. ROIs were drawn over the whole-body, organs, and different metastases (mainly in the liver). Blood samples were obtained in 12 patients after therapy with Lu-177 DOTA-TATE over 5 days for calculating the kinetics in blood. The ROI results were used to determine the uptake and effective half-life in different organs (kidney, spleen, liver, bone etc.) and the tumor residence times. By means of geometric mean, and after background correction, the ROI results were also used to calculate the estimated absorbed organ and tumor doses using the OLINDA software. Compared to Lu-177 DOTA-TATE (=100%), the uptake of Lu-177 DOTA-NOC was higher for the whole-body (45%) and for normal tissues (28%), and also in the

  9. Virus-cell fusion inhibitory activity of novel analogue peptides based on the HP (2-20) derived from N-terminus of Helicobacter pylori Ribosomal Protein L1.

    Science.gov (United States)

    Woo, Eun-Rhan; Lee, Dong Gun; Chang, Young-Su; Park, Yoonkyung; Hahm, Kyung-Soo

    2002-12-01

    HP (2-20) (AKKVFKRLEKLFSKIQNDK) is the antibacterial sequence derived from N-terminus of Helicobacter pylori Ribosomal Protein L1 (RPL1). It has a broad-spectrum microbicidal activity in vitro that is thought to be related to the membrane-disruptive properties of the peptide. Based on the putative membrane-targeted mode of action, we postulated that HP (2-20) might be possessed virus-cell fusion inhibitory activity. To develop the novel virus-cell fusion inhibitory peptides, several analogues with amino acid substitution were designed to increase or decrease only net hydrophobic region. In particular, substitution of Gln and Asp for hydrophobic amino acid, Trp at position 17 and 19 of HP (2-20) (Anal 3) caused a dramatic increase in virus-cell fusion inhibitory activity without hemolytic effect.

  10. Diversity and disparity of sparassodonts (Metatheria) reveal non-analogue nature of ancient South American mammalian carnivore guilds

    Science.gov (United States)

    Dolgushina, Tatiana; Wesley, Gina

    2018-01-01

    This study investigates whether terrestrial mammalian carnivore guilds of ancient South America, which developed in relative isolation, were similar to those of other continents. We do so through analyses of clade diversification, ecomorphology and guild structure in the Sparassodonta, metatherians that were the predominant mammalian carnivores of pre-Pleistocene South America. Body mass and 16 characters of the dentition are used to quantify morphological diversity (disparity) in sparassodonts and to compare them to extant marsupial and placental carnivores and extinct North American carnivoramorphans. We also compare trophic diversity of the Early Miocene terrestrial carnivore guild of Santa Cruz, Argentina to that of 14 modern and fossil guilds from other continents. We find that sparassodonts had comparatively low ecomorphological disparity throughout their history and that South American carnivore palaeoguilds, as represented by that of Santa Cruz, Argentina, were unlike modern or fossil carnivore guilds of other continents in their lack of mesocarnivores and hypocarnivores. Our results add to a growing body of evidence highlighting non-analogue aspects of extinct South American mammals and illustrate the dramatic effects that historical contingency can have on the evolution of mammalian palaeocommunities. PMID:29298933

  11. Modeling of the Ebola Virus Delta Peptide Reveals a Potential Lytic Sequence Motif

    Directory of Open Access Journals (Sweden)

    William R. Gallaher

    2015-01-01

    Full Text Available Filoviruses, such as Ebola and Marburg viruses, cause severe outbreaks of human infection, including the extensive epidemic of Ebola virus disease (EVD in West Africa in 2014. In the course of examining mutations in the glycoprotein gene associated with 2014 Ebola virus (EBOV sequences, a differential level of conservation was noted between the soluble form of glycoprotein (sGP and the full length glycoprotein (GP, which are both encoded by the GP gene via RNA editing. In the region of the proteins encoded after the RNA editing site sGP was more conserved than the overlapping region of GP when compared to a distant outlier species, Tai Forest ebolavirus. Half of the amino acids comprising the “delta peptide”, a 40 amino acid carboxy-terminal fragment of sGP, were identical between otherwise widely divergent species. A lysine-rich amphipathic peptide motif was noted at the carboxyl terminus of delta peptide with high structural relatedness to the cytolytic peptide of the non-structural protein 4 (NSP4 of rotavirus. EBOV delta peptide is a candidate viroporin, a cationic pore-forming peptide, and may contribute to EBOV pathogenesis.

  12. Analogue Gravity

    Directory of Open Access Journals (Sweden)

    Barceló Carlos

    2005-12-01

    Full Text Available Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.

  13. Structured pathway across the transition state for peptide folding revealed by molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Lipi Thukral

    2011-09-01

    Full Text Available Small globular proteins and peptides commonly exhibit two-state folding kinetics in which the rate limiting step of folding is the surmounting of a single free energy barrier at the transition state (TS separating the folded and the unfolded states. An intriguing question is whether the polypeptide chain reaches, and leaves, the TS by completely random fluctuations, or whether there is a directed, stepwise process. Here, the folding TS of a 15-residue β-hairpin peptide, Peptide 1, is characterized using independent 2.5 μs-long unbiased atomistic molecular dynamics (MD simulations (a total of 15 μs. The trajectories were started from fully unfolded structures. Multiple (spontaneous folding events to the NMR-derived conformation are observed, allowing both structural and dynamical characterization of the folding TS. A common loop-like topology is observed in all the TS structures with native end-to-end and turn contacts, while the central segments of the strands are not in contact. Non-native sidechain contacts are present in the TS between the only tryptophan (W11 and the turn region (P7-G9. Prior to the TS the turn is found to be already locked by the W11 sidechain, while the ends are apart. Once the ends have also come into contact, the TS is reached. Finally, along the reactive folding paths the cooperative loss of the W11 non-native contacts and the formation of the central inter-strand native contacts lead to the peptide rapidly proceeding from the TS to the native state. The present results indicate a directed stepwise process to folding the peptide.

  14. Analogue Gravity

    Directory of Open Access Journals (Sweden)

    Carlos Barceló

    2011-05-01

    Full Text Available Analogue gravity is a research programme which investigates analogues of general relativistic gravitational fields within other physical systems, typically but not exclusively condensed matter systems, with the aim of gaining new insights into their corresponding problems. Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.

  15. 'Boomerang'-like insertion of a fusogenic peptide in a lipid membrane revealed by solid-state 19F NMR.

    Science.gov (United States)

    Afonin, Sergii; Dürr, Ulrich H N; Glaser, Ralf W; Ulrich, Anne S

    2004-02-01

    Solid state (19)F NMR revealed the conformation and alignment of the fusogenic peptide sequence B18 from the sea urchin fertilization protein bindin embedded in flat phospholipid bilayers. Single (19)F labels were introduced into nine distinct positions along the wild-type sequence by substituting each hydrophobic amino acid, one by one, with L-4-fluorophenylglycine. Their anisotropic chemical shifts were measured in uniaxially oriented membrane samples and used as orientational constraints to model the peptide structure in the membrane-bound state. Previous (1)H NMR studies of B18 in 30% TFE and in detergent micelles had shown that the peptide structure consists of two alpha-helical segments that are connected by a flexible hinge. This helix-break-helix motif was confirmed here by the solid-state (19)F NMR data, while no other secondary structure (beta-sheet, 3(10)-helix) was compatible with the set of orientational constraints. For both alpha-helical segments we found that the helical conformation extends all the way to the respective N- and C-termini of the peptide. Analysis of the corresponding tilt and azimuthal rotation angles showed that the N-terminal helix of B18 is immersed obliquely into the bilayer (at a tilt angle tau approximately 54 degrees), whereas the C-terminus is peripherally aligned (tau approximately 91 degrees). The azimuthal orientation of the two segments is consistent with the amphiphilic distribution of side-chains. The observed 'boomerang'-like mode of insertion into the membrane may thus explain how peptide binding leads to lipid dehydration and acyl chain perturbation as a prerequisite for bilayer fusion to occur. Copyright 2004 John Wiley & Sons, Ltd.

  16. 99mTc Labeled Glucagon-Like Peptide-1-Analogue (99mTc-GLP1) Scintigraphy in the Management of Patients with Occult Insulinoma

    Science.gov (United States)

    Sowa-Staszczak, Anna; Trofimiuk-Müldner, Małgorzata; Stefańska, Agnieszka; Tomaszuk, Monika; Buziak-Bereza, Monika; Gilis-Januszewska, Aleksandra; Jabrocka-Hybel, Agata; Głowa, Bogusław; Małecki, Maciej; Bednarczuk, Tomasz; Kamiński, Grzegorz; Kowalska, Aldona; Mikołajczak, Renata; Janota, Barbara; Hubalewska-Dydejczyk, Alicja

    2016-01-01

    Introduction The aim of this study was to assess the utility of [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 scintigraphy in the management of patients with hypoglycemia, particularly in the detection of occult insulinoma. Materials and Methods Forty patients with hypoglycemia and increased/confusing results of serum insulin and C-peptide concentration and negative/inconclusive results of other imaging examinations were enrolled in the study. In all patients GLP-1 receptor imaging was performed to localise potential pancreatic lesions. Results Positive results of GLP-1 scintigraphy were observed in 28 patients. In 18 patients postsurgical histopathological examination confirmed diagnosis of insulinoma. Two patients had contraindications to the surgery, one patient did not want to be operated. One patient, who presented with postprandial hypoglycemia, with positive result of GLP-1 imaging was not qualified for surgery and is in the observational group. Eight patients were lost for follow up, among them 6 patients with positive GLP-1 scintigraphy result. One patient with negative scintigraphy was diagnosed with malignant insulinoma. In two patients with negative scintigraphy Munchausen syndrome was diagnosed (patients were taking insulin). Other seven patients with negative results of 99mTcGLP-1 scintigraphy and postprandial hypoglycemia with C-peptide and insulin levels within the limits of normal ranges are in the observational group. We would like to mention that 99mTc-GLP1-SPECT/CT was also performed in 3 pts with nesidioblastosis (revealing diffuse tracer uptake in two and a focal lesion in one case) and in two patients with malignant insulinoma (with the a focal uptake in the localization of a removed pancreatic headin one case and negative GLP-1 1 scintigraphy in the other patient). Conclusions 99mTc-GLP1-SPECT/CT could be helpful examination in the management of patients with hypoglycemia enabling proper localization of the pancreatic lesion and effective

  17. NMR structure determination of a synthetic analogue of bacillomycin Lc reveals the strategic role of L-Asn1 in the natural iturinic antibiotics

    Science.gov (United States)

    Volpon, Laurent; Tsan, Pascale; Majer, Zsuzsa; Vass, Elemer; Hollósi, Miklós; Noguéra, Valérie; Lancelin, Jean-Marc; Besson, Françoise

    2007-08-01

    Iturins are a group of antifungal produced by Bacillus subtilis. All are cyclic lipopeptides with seven α-amino acids of configuration LDDLLDL and one β-amino fatty acid. The bacillomycin L is a member of this family and its NMR structure was previously resolved using the sequence Asp-Tyr-Asn-Ser-Gln-Ser-Thr. In this work, we carefully examined the NMR spectra of this compound and detected an error in the sequence. In fact, Asp1 and Gln5 need to be changed into Asn1 and Glu5, which therefore makes it identical to bacillomycin Lc. As a consequence, it now appears that all iturinic peptides with antibiotic activity share the common β-amino fatty acid 8- L-Asn1- D-Tyr2- D-Asn3 sequence. To better understand the conformational influence of the acidic residue L-Asp1, present, for example in the inactive iturin C, the NMR structure of the synthetic analogue SCP [cyclo ( L-Asp1- D-Tyr2- D-Asn3- L-Ser4- L-Gln5- D-Ser6- L-Thr7-β-Ala8)] was determined and compared with bacillomycin Lc recalculated with the corrected sequence. In both cases, the conformers obtained were separated into two families of similar energy which essentially differ in the number and type of turns. A detailed analysis of both cyclopeptide structures is presented here. In addition, CD and FTIR spectra were performed and confirmed the conformational differences observed by NMR between both cyclopeptides.

  18. The glucagon-like peptide 1 analogue Exendin-4 attenuates the nicotine-induced locomotor stimulation, accumbal dopamine release, conditioned place preference as well as the expression of locomotor sensitization in mice.

    Directory of Open Access Journals (Sweden)

    Emil Egecioglu

    Full Text Available The gastrointestinal peptide glucagon-like peptide 1 (GLP-1 is known to regulate consummatory behavior and is released in response to nutrient ingestion. Analogues of this peptide recently emerged as novel pharmacotherapies for treatment of type II diabetes since they reduce gastric emptying, glucagon secretion as well as enhance glucose-dependent insulin secretion. The findings that GLP-1 targets reward related areas including mesolimbic dopamine areas indicate that the physiological role of GLP-1 extends beyond food intake and glucose homeostasis control to include reward regulation. The present series of experiments was therefore designed to investigate the effects of the GLP-1 receptor agonist, Exendin-4 (Ex4, on established nicotine-induced effects on the mesolimbic dopamine system in mice. Specifically, we show that treatment with Ex4, at a dose with no effect per se, attenuate nicotine-induced locomotor stimulation, accumbal dopamine release as well as the expression of conditioned place preference in mice. In accordance, Ex4 also blocks nicotine-induced expression of locomotor sensitization in mice. Given that development of nicotine addiction largely depends on the effects of nicotine on the mesolimbic dopamine system these findings indicate that the GLP-1 receptor may be a potential target for the development of novel treatment strategies for nicotine cessations in humans.

  19. Comparison of Cytotoxic Activity in Leukemic Lineages Reveals Important Features of β-Hairpin Antimicrobial Peptides.

    Science.gov (United States)

    Buri, Marcus V; Torquato, Heron F Vieira; Barros, Carlos Castilho; Ide, Jaime S; Miranda, Antonio; Paredes-Gamero, Edgar J

    2017-07-01

    Several reports described different modes of cell death triggered by antimicrobial peptides (AMPs) due to direct effects on membrane disruption, and more recently by apoptosis and necrosis-like patterns. Cytotoxic curves of four β-hairpin AMPs (gomesin, protegrin, tachyplesin, and polyphemusin) were obtained from several human leukemic lineages and normal monocytes and Two cell lines were then selected based on their cytotoxic sensitivity. One was sensitive to AMPs (K562) and the other resistant (KG-1) and their effect compared between these lineages. Thus, these lineages were chosen to further investigate biological features related with their cytotoxicities to AMPs. Stimulation with AMPs produced cell death, with activation of caspase-3, in K562 lineage. Increase on the fluidity of plasmatic membrane by reducing cholesterol potentiated cytotoxicity of AMPs in both lineages. Quantification of internal and external gomesin binding to the cellular membrane of both K562 and KG-1 cells showed that more peptide is accumulated inside of K562 cells. Additionally, evaluation of multi-drug resistant pumps activity showed that KG-1 has more activity than K562 lineage. A comparison of intrinsic gene patterns showed great differences between K562 and KG-1, but stimulation with gomesin promoted few changes in gene expression patterns. Differences in internalization process through the plasma membrane, multidrug resistance pumps activity, and gene expression pattern are important features to AMPs regulated cell death. J. Cell. Biochem. 118: 1764-1773, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. SANDPUMA: ensemble predictions of nonribosomal peptide chemistry reveal biosynthetic diversity across Actinobacteria.

    Science.gov (United States)

    Chevrette, Marc G; Aicheler, Fabian; Kohlbacher, Oliver; Currie, Cameron R; Medema, Marnix H

    2017-10-15

    Nonribosomally synthesized peptides (NRPs) are natural products with widespread applications in medicine and biotechnology. Many algorithms have been developed to predict the substrate specificities of nonribosomal peptide synthetase adenylation (A) domains from DNA sequences, which enables prioritization and dereplication, and integration with other data types in discovery efforts. However, insufficient training data and a lack of clarity regarding prediction quality have impeded optimal use. Here, we introduce prediCAT, a new phylogenetics-inspired algorithm, which quantitatively estimates the degree of predictability of each A-domain. We then systematically benchmarked all algorithms on a newly gathered, independent test set of 434 A-domain sequences, showing that active-site-motif-based algorithms outperform whole-domain-based methods. Subsequently, we developed SANDPUMA, a powerful ensemble algorithm, based on newly trained versions of all high-performing algorithms, which significantly outperforms individual methods. Finally, we deployed SANDPUMA in a systematic investigation of 7635 Actinobacteria genomes, suggesting that NRP chemical diversity is much higher than previously estimated. SANDPUMA has been integrated into the widely used antiSMASH biosynthetic gene cluster analysis pipeline and is also available as an open-source, standalone tool. SANDPUMA is freely available at https://bitbucket.org/chevrm/sandpuma and as a docker image at https://hub.docker.com/r/chevrm/sandpuma/ under the GNU Public License 3 (GPL3). chevrette@wisc.edu or marnix.medema@wur.nl. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  1. In Situ and Real-Time SFG Measurements Revealing Organization and Transport of Cholesterol Analogue 6-Ketocholestanol in a Cell Membrane.

    Science.gov (United States)

    Ma, Sulan; Li, Hongchun; Tian, Kangzhen; Ye, Shuji; Luo, Yi

    2014-02-06

    Cholesterol organization and transport within a cell membrane are essential for human health and many cellular functions yet remain elusive so far. Using cholesterol analogue 6-ketocholestanol (6-KC) as a model, we have successfully exploited sum frequency generation vibrational spectroscopy (SFG-VS) to track the organization and transport of cholesterol in a membrane by combining achiral-sensitive ssp (ppp) and chiral-sensitive psp polarization measurements. It is found that 6-KC molecules are aligned at the outer leaflet of the DMPC lipid bilayer with a tilt angle of about 10°. 6-KC organizes itself by forming an α-β structure at low 6-KC concentration and most likely a β-β structure at high 6-KC concentration. Among all proposed models, our results favor the so-called umbrella model with formation of a 6-KC cluster. Moreover, we have found that the long anticipated flip-flop motion of 6-KC in the membrane takes time to occur, at least much longer than previously thought. All of these interesting findings indicate that it is critical to explore in situ, real-time, and label-free methodologies to obtain a precise molecular description of cholesterol's behavior in membranes. This study represents the first application of SFG to reveal the cholesterol-lipid interaction mechanism at the molecular level.

  2. Acute effects of the Glucagon-Like Peptide 2 analogue, teduglutide, on intestinal adaptation in newborn pigs with short bowel syndrome

    DEFF Research Database (Denmark)

    Thymann, Thomas; Stoll, Barbara; Mecklenburg, Lars

    2014-01-01

    Neonatal short bowel syndrome following massive gut resection associates with malabsorption of nutrients. The intestinotrophic factor glucagon-like peptide 2 (GLP-2) improves gut function in adult short bowel patients, but its effect in pediatric patients remains unknown. Our objective was to test...

  3. Antimicrobial Peptide from the Wild Bee Hylaeus signatus Venom and Its Analogues: Structure-Activity Study and Synergistic Effect with Antibiotics

    Czech Academy of Sciences Publication Activity Database

    Nešuta, Ondřej; Hexnerová, Rozálie; Buděšínský, Miloš; Slaninová, Jiřina; Bednárová, Lucie; Hadravová, Romana; Straka, J.; Veverka, Václav; Čeřovský, Václav

    2016-01-01

    Roč. 79, č. 4 (2016), s. 1073-1083 ISSN 0163-3864 R&D Projects: GA TA ČR(CZ) TA04010638; GA MŠk(CZ) LO1304 Institutional support: RVO:61388963 Keywords : alpha-helical peptides * in vitro activity * Pseudomonas aeruginosa Subject RIV: CC - Organic Chemistry Impact factor: 3.281, year: 2016

  4. Synthesis of a Hoechst 32258 Analogue Amino Acid Building Block for Direct Incorporation of a Fluorescent High-Affinity DNA Binding Motif into Peptides

    DEFF Research Database (Denmark)

    Harrit, Niels; Behrens, Carsten; Nielsen, P. E.

    2001-01-01

    The synthesis of a new versatile "Hoechst 33258-like" Boc-protected amino acid building block for peptide synthesis is described. It is demonstrated that this new ligand is an effective mimic of Hoechst 33258 in terms of DNA affinity and sequence specificity. Furthermore, this minor groove binder...

  5. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy.

    Science.gov (United States)

    Imaoka, Naruaki; Houferak, Camille; Murphy, Megan P; Nguyen, Huong T H; Dang, Andy; Tureček, František

    2018-01-16

    Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z 4 + H] +● fragment ion-radicals of the R-C ● H-CONH- type, initially formed by N-C α bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [ ● DAAR + H] + isomers and used to assign structures to the action spectra. The potential energy surface of [ ● DAAR + H] + isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [ ● XAAR + H] + ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone C α positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H] ● -ETD fragments containing Asp, Asn, Glu, and Gln residues. Graphical Abstract ᅟ.

  6. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy

    Science.gov (United States)

    Imaoka, Naruaki; Houferak, Camille; Murphy, Megan P.; Nguyen, Huong T. H.; Dang, Andy; Tureček, František

    2018-01-01

    Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z4 + H]+● fragment ion-radicals of the R-C●H-CONH- type, initially formed by N-Cα bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [●DAAR + H]+ isomers and used to assign structures to the action spectra. The potential energy surface of [●DAAR + H]+ isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [●XAAR + H]+ ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone Cα positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H]●-ETD fragments containing Asp, Asn, Glu, and Gln residues. [Figure not available: see fulltext.

  7. BALANOL ANALOGUES

    DEFF Research Database (Denmark)

    1997-01-01

    The present invention relates to a solid phase methodology for the preparation of a combinatorial library of structural analogues of the natural product balanol (ophiocordin, azepinostatin), which is a protein kinase C (PKC) and protein kinase A (PKA) inhibitor. The method comprises solid...

  8. Transcriptome of Dickeya dadantii infecting Acyrthosiphon pisum reveals a strong defense against antimicrobial peptides.

    Science.gov (United States)

    Costechareyre, Denis; Chich, Jean-François; Strub, Jean-Marc; Rahbé, Yvan; Condemine, Guy

    2013-01-01

    The plant pathogenic bacterium Dickeya dadantii has recently been shown to be able to kill the aphid Acyrthosiphon pisum. While the factors required to cause plant disease are now well characterized, those required for insect pathogeny remain mostly unknown. To identify these factors, we analyzed the transcriptome of the bacteria isolated from infected aphids. More than 150 genes were upregulated and 300 downregulated more than 5-fold at 3 days post infection. No homologue to known toxin genes could be identified in the upregulated genes. The upregulated genes reflect the response of the bacteria to the conditions encountered inside aphids. While only a few genes involved in the response to oxidative stress were induced, a strong defense against antimicrobial peptides (AMP) was induced. Expression of a great number of efflux proteins and transporters was increased. Besides the genes involved in LPS modification by addition of 4-aminoarabinose (the arnBCADTEF operon) and phosphoethanolamine (pmrC, eptB) usually induced in Gram negative bacteria in response to AMPs, dltBAC and pbpG genes, which confer Gram positive bacteria resistance to AMPs by adding alanine to teichoic acids, were also induced. Both types of modification confer D. dadantii resistance to the AMP polymyxin. A. pisum harbors symbiotic bacteria and it is thought that it has a very limited immune system to maintain these populations and do not synthesize AMPs. The arnB mutant was less pathogenic to A. pisum, which suggests that, in contrast to what has been supposed, aphids do synthesize AMP.

  9. Transcriptome of Dickeya dadantii infecting Acyrthosiphon pisum reveals a strong defense against antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Denis Costechareyre

    Full Text Available The plant pathogenic bacterium Dickeya dadantii has recently been shown to be able to kill the aphid Acyrthosiphon pisum. While the factors required to cause plant disease are now well characterized, those required for insect pathogeny remain mostly unknown. To identify these factors, we analyzed the transcriptome of the bacteria isolated from infected aphids. More than 150 genes were upregulated and 300 downregulated more than 5-fold at 3 days post infection. No homologue to known toxin genes could be identified in the upregulated genes. The upregulated genes reflect the response of the bacteria to the conditions encountered inside aphids. While only a few genes involved in the response to oxidative stress were induced, a strong defense against antimicrobial peptides (AMP was induced. Expression of a great number of efflux proteins and transporters was increased. Besides the genes involved in LPS modification by addition of 4-aminoarabinose (the arnBCADTEF operon and phosphoethanolamine (pmrC, eptB usually induced in Gram negative bacteria in response to AMPs, dltBAC and pbpG genes, which confer Gram positive bacteria resistance to AMPs by adding alanine to teichoic acids, were also induced. Both types of modification confer D. dadantii resistance to the AMP polymyxin. A. pisum harbors symbiotic bacteria and it is thought that it has a very limited immune system to maintain these populations and do not synthesize AMPs. The arnB mutant was less pathogenic to A. pisum, which suggests that, in contrast to what has been supposed, aphids do synthesize AMP.

  10. A standardised study to compare prostate cancer targeting efficacy of five radiolabelled bombesin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Rogier P.J. [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Erasmus MC, Department of Experimental Urology, Rotterdam (Netherlands); Mueller, Cristina; Melis, Marleen L.; Breeman, Wout A.P.; Blois, Erik de; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Reneman, Suzanne; Bangma, Chris H.; Weerden, Wytske M. van [Erasmus MC, Department of Experimental Urology, Rotterdam (Netherlands)

    2010-07-15

    Prostate-specific antigen (PSA)-based screening for prostate cancer (PC) has dramatically increased early diagnosis. Current imaging techniques are not optimal to stage early PC adequately. A promising alternative to PC imaging is peptide-based scintigraphy using radiolabelled bombesin (BN) analogues that bind to gastrin-releasing peptide receptors (GRPR) being overexpressed in PC. When labelled to appropriate radionuclides BN targeting of GRPRs may also provide applications for peptide radionuclide receptor therapy (PRRT). Assessment studies under identical experimental conditions allowing a reliable comparison of the potential of such analogues are lacking. This study was performed to evaluate and directly compare five promising radiolabelled BN analogues for their targeting efficacy for PC under standardised conditions. The BN agonists [{sup 111}In]DOTA-PESIN, [{sup 111}In]AMBA, [{sup 111}In]MP2346 and [{sup 111}In]MP2653 and one antagonist [{sup 99m}Tc]Demobesin-1 were evaluated in GRPR-overexpressing human PC-3 tumour-bearing mice to determine peptide stability in vivo, biodistribution and GRPR targeting potential by animal SPECT/CT imaging and ex vivo autoradiography. HPLC analysis of blood showed intact Demobesin-1 at 5 and 15 min after injection (64.1{+-}1.6% and 41.0{+-}01%, respectively) being much less for the other compounds. AMBA, the second most stable analogue, showed 36.1{+-}2.7% and 9.8{+-}1.1% intact peptide after 5 and 15 min. PC-3 tumour uptake at 1 h was comparable for Demobesin-1, AMBA, PESIN and MP2346 (3.0{+-}0.4, 2.7{+-}0.5, 2.3{+-}0.5 and 2.1{+-}0.9%ID/g, respectively), but very low for MP2653 (0.9 {+-} 0.2%ID/g). In addition, MP2346 showed undesirably high uptake in the kidneys (7.9{+-}1.9%ID/g) being significantly less for the other analogues. AMBA, MP2346 and PESIN revealed favourable increases in tumour to blood ratios over time while changes in tumour to kidney and pancreas ratios for Demobesin-1 from 1 to 24 h after injection were

  11. 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.)

  12. Crystal structure of a TAPBPR–MHC I complex reveals the mechanism of peptide editing in antigen presentation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jiansheng; Natarajan, Kannan; Boyd, Lisa F.; Morozov, Giora I.; Mage, Michael G.; Margulies, David H. (NIH); (Hebrew)

    2017-10-12

    Central to CD8+ T cell–mediated immunity is the recognition of peptide–major histocompatibility complex class I (p–MHC I) proteins displayed by antigen-presenting cells. Chaperone-mediated loading of high-affinity peptides onto MHC I is a key step in the MHC I antigen presentation pathway. However, the structure of MHC I with a chaperone that facilitates peptide loading has not been determined. We report the crystal structure of MHC I in complex with the peptide editor TAPBPR (TAP-binding protein–related), a tapasin homolog. TAPBPR remodels the peptide-binding groove of MHC I, resulting in the release of low-affinity peptide. Changes include groove relaxation, modifications of key binding pockets, and domain adjustments. This structure captures a peptide-receptive state of MHC I and provides insights into the mechanism of peptide editing by TAPBPR and, by analogy, tapasin.

  13. AaeAP1 and AaeAP2: novel antimicrobial peptides from the venom of the scorpion, Androctonus aeneas: structural characterisation, molecular cloning of biosynthetic precursor-encoding cDNAs and engineering of analogues with enhanced antimicrobial and anticancer activities.

    Science.gov (United States)

    Du, Qiang; Hou, Xiaojuan; Wang, Lei; Zhang, Yingqi; Xi, Xinping; Wang, Hui; Zhou, Mei; Duan, Jinao; Wei, Minjie; Chen, Tianbao; Shaw, Chris

    2015-01-23

    The main functions of the abundant polypeptide toxins present in scorpion venoms are the debilitation of arthropod prey or defence against predators. These effects are achieved mainly through the blocking of an array of ion channel types within the membranes of excitable cells. However, while these ion channel-blocking toxins are tightly-folded by multiple disulphide bridges between cysteine residues, there are additional groups of peptides in the venoms that are devoid of cysteine residues. These non-disulphide bridged peptides are the subject of much research interest, and among these are peptides that exhibit antimicrobial activity. Here, we describe two novel non-disulphide-bridged antimicrobial peptides that are present in the venom of the North African scorpion, Androctonus aeneas. The cDNAs encoding the biosynthetic precursors of both peptides were cloned from a venom-derived cDNA library using 3'- and 5'-RACE strategies. Both translated precursors contained open-reading frames of 74 amino acid residues, each encoding one copy of a putative novel nonadecapeptide, whose primary structures were FLFSLIPSVIAGLVSAIRN and FLFSLIPSAIAGLVSAIRN, respectively. Both peptides were C-terminally amidated. Synthetic versions of each natural peptide displayed broad-spectrum antimicrobial activities, but were devoid of antiproliferative activity against human cancer cell lines. However, synthetic analogues of each peptide, engineered for enhanced cationicity and amphipathicity, exhibited increases in antimicrobial potency and acquired antiproliferative activity against a range of human cancer cell lines. These data clearly illustrate the potential that natural peptide templates provide towards the design of synthetic analogues for therapeutic exploitation.

  14. AaeAP1 and AaeAP2: Novel Antimicrobial Peptides from the Venom of the Scorpion, Androctonus aeneas: Structural Characterisation, Molecular Cloning of Biosynthetic Precursor-Encoding cDNAs and Engineering of Analogues with Enhanced Antimicrobial and Anticancer Activities

    Directory of Open Access Journals (Sweden)

    Qiang Du

    2015-01-01

    Full Text Available The main functions of the abundant polypeptide toxins present in scorpion venoms are the debilitation of arthropod prey or defence against predators. These effects are achieved mainly through the blocking of an array of ion channel types within the membranes of excitable cells. However, while these ion channel-blocking toxins are tightly-folded by multiple disulphide bridges between cysteine residues, there are additional groups of peptides in the venoms that are devoid of cysteine residues. These non-disulphide bridged peptides are the subject of much research interest, and among these are peptides that exhibit antimicrobial activity. Here, we describe two novel non-disulphide-bridged antimicrobial peptides that are present in the venom of the North African scorpion, Androctonus aeneas. The cDNAs encoding the biosynthetic precursors of both peptides were cloned from a venom-derived cDNA library using 3'- and 5'-RACE strategies. Both translated precursors contained open-reading frames of 74 amino acid residues, each encoding one copy of a putative novel nonadecapeptide, whose primary structures were FLFSLIPSVIAGLVSAIRN and FLFSLIPSAIAGLVSAIRN, respectively. Both peptides were C-terminally amidated. Synthetic versions of each natural peptide displayed broad-spectrum antimicrobial activities, but were devoid of antiproliferative activity against human cancer cell lines. However, synthetic analogues of each peptide, engineered for enhanced cationicity and amphipathicity, exhibited increases in antimicrobial potency and acquired antiproliferative activity against a range of human cancer cell lines. These data clearly illustrate the potential that natural peptide templates provide towards the design of synthetic analogues for therapeutic exploitation.

  15. Helper T cell epitope-mapping reveals MHC-peptide binding affinities that correlate with T helper cell responses to pneumococcal surface protein A.

    Directory of Open Access Journals (Sweden)

    Rajesh Singh

    2010-02-01

    Full Text Available Understanding the requirements for protection against pneumococcal carriage and pneumonia will greatly benefit efforts in controlling these diseases. Several proteins and polysaccharide capsule have recently been implicated in the virulence of and protective immunity against Streptococcus pneumonia. Pneumococcal surface protein A (PspA is highly conserved among S. pneumonia strains, inhibits complement activation, binds lactoferrin, elicits protective systemic immunity against pneumococcal infection, and is necessary for full pneumococcal virulence. Identification of PspA peptides that optimally bind human leukocyte antigen (HLA would greatly contribute to global vaccine efforts, but this is hindered by the multitude of HLA polymorphisms. Here, we have used an experimental data set of 54 PspA peptides and in silico methods to predict peptide binding to HLA and murine major histocompatibility complex (MHC class II. We also characterized spleen- and cervical lymph node (CLN-derived helper T lymphocyte (HTL cytokine responses to these peptides after S. pneumonia strain EF3030-challenge in mice. Individual, yet overlapping peptides, 15 amino acids in length revealed residues 199 to 246 of PspA (PspA(199-246 consistently caused the greatest IFN-gamma, IL-2, IL-5 and proliferation as well as moderate IL-10 and IL-4 responses by ex vivo stimulated splenic and CLN CD4(+ T cells isolated from S. pneumonia strain EF3030-challeged F(1 (B6xBALB/c mice. IEDB, RANKPEP, SVMHC, MHCPred, and SYFPEITHI in silico analysis tools revealed peptides in PspA(199-246 also interact with a broad range of HLA-DR, -DQ, and -DP allelles. These data suggest that predicted MHC class II-peptide binding affinities do not always correlate with T helper (Th cytokine or proliferative responses to PspA peptides, but when used together with in vivo validation can be a useful tool to choose candidate pneumococcal HTL epitopes.

  16. Dynamic membrane interactions of antibacterial and antifungal biomolecules, and amyloid peptides, revealed by solid-state NMR spectroscopy.

    Science.gov (United States)

    Naito, Akira; Matsumori, Nobuaki; Ramamoorthy, Ayyalusamy

    2018-02-01

    A variety of biomolecules acting on the cell membrane folds into a biologically active structure in the membrane environment. It is, therefore, important to determine the structures and dynamics of such biomolecules in a membrane environment. While several biophysical techniques are used to obtain low-resolution information, solid-state NMR spectroscopy is one of the most powerful means for determining the structure and dynamics of membrane bound biomolecules such as antibacterial biomolecules and amyloidogenic proteins; unlike X-ray crystallography and solution NMR spectroscopy, applications of solid-state NMR spectroscopy are not limited by non-crystalline, non-soluble nature or molecular size of membrane-associated biomolecules. This review article focuses on the applications of solid-state NMR techniques to study a few selected antibacterial and amyloid peptides. Solid-state NMR studies revealing the membrane inserted bent α-helical structure associated with the hemolytic activity of bee venom melittin and the chemical shift oscillation analysis used to determine the transmembrane structure (with α-helix and 3 10 -helix in the N- and C-termini, respectively) of antibiotic peptide alamethicin are discussed in detail. Oligomerization of an amyloidogenic islet amyloid polypeptide (IAPP, or also known as amylin) resulting from its aggregation in a membrane environment, molecular interactions of the antifungal natural product amphotericin B with ergosterol in lipid bilayers, and the mechanism of lipid raft formation by sphingomyelin studied using solid state NMR methods are also discussed in this review article. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Structure-Related Roles for the Conservation of the HIV-1 Fusion Peptide Sequence Revealed by Nuclear Magnetic Resonance.

    Science.gov (United States)

    Serrano, Soraya; Huarte, Nerea; Rujas, Edurne; Andreu, David; Nieva, José L; Jiménez, María Angeles

    2017-10-17

    Despite extensive characterization of the human immunodeficiency virus type 1 (HIV-1) hydrophobic fusion peptide (FP), the structure-function relationships underlying its extraordinary degree of conservation remain poorly understood. Specifically, the fact that the tandem repeat of the FLGFLG tripeptide is absolutely conserved suggests that high hydrophobicity may not suffice to unleash FP function. Here, we have compared the nuclear magnetic resonance (NMR) structures adopted in nonpolar media by two FP surrogates, wtFP-tag and scrFP-tag, which had equal hydrophobicity but contained wild-type and scrambled core sequences LFLGFLG and FGLLGFL, respectively. In addition, these peptides were tagged at their C-termini with an epitope sequence that folded independently, thereby allowing Western blot detection without interfering with FP structure. We observed similar α-helical FP conformations for both specimens dissolved in the low-polarity medium 25% (v/v) 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), but important differences in contact with micelles of the membrane mimetic dodecylphosphocholine (DPC). Thus, whereas wtFP-tag preserved a helix displaying a Gly-rich ridge, the scrambled sequence lost in great part the helical structure upon being solubilized in DPC. Western blot analyses further revealed the capacity of wtFP-tag to assemble trimers in membranes, whereas membrane oligomers were not observed in the case of the scrFP-tag sequence. We conclude that, beyond hydrophobicity, preserving sequence order is an important feature for defining the secondary structures and oligomeric states adopted by the HIV FP in membranes.

  18. Gastrin-releasing peptide receptor-based targeting using bombesin analogues is superior to metabolism-based targeting using choline for in vivo imaging of human prostate cancer xenografts

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Rogier P.J. [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Erasmus MC, Department of Urology, Rotterdam (Netherlands); Weerden, W.M. van; Bangma, C.H.; Reneman, S. [Erasmus MC, Department of Urology, Rotterdam (Netherlands); Krenning, E.P.; Berndsen, S.; Grievink-de Ligt, C.H.; Groen, H.C.; Blois, E. de; Breeman, W.A.P.; Jong, M. de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands)

    2011-07-15

    Prostate cancer (PC) is a major health problem. Overexpression of the gastrin-releasing peptide receptor (GRPR) in PC, but not in the hyperplastic prostate, provides a promising target for staging and monitoring of PC. Based on the assumption that cancer cells have increased metabolic activity, metabolism-based tracers are also being used for PC imaging. We compared GRPR-based targeting using the {sup 68}Ga-labelled bombesin analogue AMBA with metabolism-based targeting using {sup 18}F-methylcholine ({sup 18}F-FCH) in nude mice bearing human prostate VCaP xenografts. PET and biodistribution studies were performed with both {sup 68}Ga-AMBA and {sup 18}F-FCH in all VCaP tumour-bearing mice, with PC-3 tumour-bearing mice as reference. Scanning started immediately after injection. Dynamic PET scans were reconstructed and analysed quantitatively. Biodistribution of tracers and tissue uptake was expressed as percent of injected dose per gram tissue (%ID/g). All tumours were clearly visualized using {sup 68}Ga-AMBA. {sup 18}F-FCH showed significantly less contrast due to poor tumour-to-background ratios. Quantitative PET analyses showed fast tumour uptake and high retention for both tracers. VCaP tumour uptake values determined from PET at steady-state were 6.7 {+-} 1.4%ID/g (20-30 min after injection, N = 8) for {sup 68}Ga-AMBA and 1.6 {+-} 0.5%ID/g (10-20 min after injection, N = 8) for {sup 18}F-FCH, which were significantly different (p <0.001). The results in PC-3 tumour-bearing mice were comparable. Biodistribution data were in accordance with the PET results showing VCaP tumour uptake values of 9.5 {+-} 4.8%ID/g (N = 8) for {sup 68}Ga-AMBA and 2.1 {+-} 0.4%ID/g (N = 8) for {sup 18}F-FCH. Apart from the GRPR-expressing organs, uptake in all organs was lower for {sup 68}Ga-AMBA than for {sup 18}F-FCH. Tumour uptake of {sup 68}Ga-AMBA was higher while overall background activity was lower than observed for {sup 18}F-FCH in the same PC-bearing mice. These results

  19. The architecture of amyloid-like peptide fibrils revealed by X-ray scattering, diffraction and electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Langkilde, Annette E., E-mail: annette.langkilde@sund.ku.dk [University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen (Denmark); Morris, Kyle L.; Serpell, Louise C. [University of Sussex, Falmer, Brighton (United Kingdom); Svergun, Dmitri I. [European Molecular Biology Laboratory, Hamburg Outstation, 22607 Hamburg (Germany); Vestergaard, Bente [University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen (Denmark)

    2015-04-01

    The aggregation process and the fibril state of an amyloidogenic peptide suggest monomer addition to be the prevailing mechanism of elongation and a model of the peptide packing in the fibrils has been obtained. Structural analysis of protein fibrillation is inherently challenging. Given the crucial role of fibrils in amyloid diseases, method advancement is urgently needed. A hybrid modelling approach is presented enabling detailed analysis of a highly ordered and hierarchically organized fibril of the GNNQQNY peptide fragment of a yeast prion protein. Data from small-angle X-ray solution scattering, fibre diffraction and electron microscopy are combined with existing high-resolution X-ray crystallographic structures to investigate the fibrillation process and the hierarchical fibril structure of the peptide fragment. The elongation of these fibrils proceeds without the accumulation of any detectable amount of intermediate oligomeric species, as is otherwise reported for, for example, glucagon, insulin and α-synuclein. Ribbons constituted of linearly arranged protofilaments are formed. An additional hierarchical layer is generated via the pairing of ribbons during fibril maturation. Based on the complementary data, a quasi-atomic resolution model of the protofilament peptide arrangement is suggested. The peptide structure appears in a β-sheet arrangement reminiscent of the β-zipper structures evident from high-resolution crystal structures, with specific differences in the relative peptide orientation. The complexity of protein fibrillation and structure emphasizes the need to use multiple complementary methods.

  20. Cleaving Double-Stranded DNA with Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1997-01-01

    Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest......, transcription initiation, and site specific cleavage of nucleic acids....

  1. An immunoproteomic approach revealing peptides from Sporothrix brasiliensis that induce a cellular immune response in subcutaneous sporotrichosis.

    Science.gov (United States)

    de Almeida, José Roberto Fogaça; Jannuzzi, Grasielle Pereira; Kaihami, Gilberto Hideo; Breda, Leandro Carvalho Dantas; Ferreira, Karen Spadari; de Almeida, Sandro Rogério

    2018-03-08

    Sporothrix brasiliensis is the most virulent fungus of the Sporothrix complex and is the main species recovered in the sporotrichosis zoonotic hyperendemic area in Rio de Janeiro. A vaccine against S. brasiliensis could improve the current sporotrichosis situation. Here, we show 3 peptides from S. brasiliensis immunogenic proteins that have a higher likelihood for engaging MHC-class II molecules. We investigated the efficiency of the peptides as vaccines for preventing subcutaneous sporotrichosis. In this study, we observed a decrease in lesion diameters in peptide-immunized mice, showing that the peptides could induce a protective immune response against subcutaneous sporotrichosis. ZR8 peptide is from the GP70 protein, the main antigen of the Sporothrix complex, and was the best potential vaccine candidate by increasing CD4 + T cells and higher levels of IFN-γ, IL-17A and IL-1β characterizing a strong cellular immune response. This immune environment induced a higher number of neutrophils in lesions that are associated with fungus clearance. These results indicated that the ZR8 peptide induces a protective immune response against subcutaneous sporotrichosis and is a vaccine candidate against S. brasiliensis infection.

  2. Physiologically-Relevant Modes of Membrane Interactions by the Human Antimicrobial Peptide, LL-37, Revealed by SFG Experiments

    Science.gov (United States)

    Ding, Bei; Soblosky, Lauren; Nguyen, Khoi; Geng, Junqing; Yu, Xinglong; Ramamoorthy, Ayyalusamy; Chen, Zhan

    2013-05-01

    Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process.

  3. Enzymatic synthesis of RNAs capped with nucleotide analogues reveals the molecular basis for substrate selectivity of RNA capping enzyme: impacts on RNA metabolism.

    Directory of Open Access Journals (Sweden)

    Moheshwarnath Issur

    Full Text Available RNA cap binding proteins have evolved to specifically bind to the N7-methyl guanosine cap structure found at the 5' ends of eukaryotic mRNAs. The specificity of RNA capping enzymes towards GTP for the synthesis of this structure is therefore crucial for mRNA metabolism. The fact that ribavirin triphosphate was described as a substrate of a viral RNA capping enzyme, raised the possibility that RNAs capped with nucleotide analogues could be generated in cellulo. Owing to the fact that this prospect potentially has wide pharmacological implications, we decided to investigate whether the active site of the model Paramecium bursaria Chlorella virus-1 RNA capping enzyme was flexible enough to accommodate various purine analogues. Using this approach, we identified several key structural determinants at each step of the RNA capping reaction and generated RNAs harboring various different cap analogues. Moreover, we monitored the binding affinity of these novel capped RNAs to the eIF4E protein and evaluated their translational properties in cellulo. Overall, this study establishes a molecular rationale for the specific selection of GTP over other NTPs by RNA capping enzyme It also demonstrates that RNAs can be enzymatically capped with certain purine nucleotide analogs, and it also describes the impacts of modified RNA caps on specific steps involved in mRNA metabolism. For instance, our results indicate that the N7-methyl group of the classical N7-methyl guanosine cap is not always indispensable for binding to eIF4E and subsequently for translation when compensatory modifications are present on the capped residue. Overall, these findings have important implications for our understanding of the molecular determinants involved in both RNA capping and RNA metabolism.

  4. c-MYC G-quadruplex binding by the RNA polymerase I inhibitor BMH-21 and analogues revealed by a combined NMR and biochemical Approach.

    Science.gov (United States)

    Musso, Loana; Mazzini, Stefania; Rossini, Anna; Castagnoli, Lorenzo; Scaglioni, Leonardo; Artali, Roberto; Di Nicola, Massimo; Zunino, Franco; Dallavalle, Sabrina

    2018-03-01

    Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of human tumor cell lines and protein expression was examined by Western Blot analysis. We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in human tumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A thiamin-bound, pre-decarboxylation reaction intermediate analogue in the pyruvate dehydrogenase E1 subunit induces large scale disorder-to-order transformations in the enzyme and reveals novel structural features in the covalently bound adduct.

    Science.gov (United States)

    Arjunan, Palaniappa; Sax, Martin; Brunskill, Andrew; Chandrasekhar, Krishnamoorthy; Nemeria, Natalia; Zhang, Sheng; Jordan, Frank; Furey, William

    2006-06-02

    The crystal structure of the E1 component from the Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc) has been determined with phosphonolactylthiamin diphosphate (PLThDP) in its active site. PLThDP serves as a structural and electrostatic analogue of the natural intermediate alpha-lactylthiamin diphosphate (LThDP), in which the carboxylate from the natural substrate pyruvate is replaced by a phosphonate group. This represents the first example of an experimentally determined, three-dimensional structure of a thiamin diphosphate (ThDP)-dependent enzyme containing a covalently bound, pre-decarboxylation reaction intermediate analogue and should serve as a model for the corresponding intermediates in other ThDP-dependent decarboxylases. Regarding the PDHc-specific reaction, the presence of PLThDP induces large scale conformational changes in the enzyme. In conjunction with the E1-PLThDP and E1-ThDP structures, analysis of a H407A E1-PLThDP variant structure shows that an interaction between His-407 and PLThDP is essential for stabilization of two loop regions in the active site that are otherwise disordered in the absence of intermediate analogue. This ordering completes formation of the active site and creates a new ordered surface likely involved in interactions with the lipoyl domains of E2s within the PDHc complex. The tetrahedral intermediate analogue is tightly held in the active site through direct hydrogen bonds to residues His-407, Tyr-599, and His-640 and reveals a new, enzyme-induced, strain-related feature that appears to aid in the decarboxylation process. This feature is almost certainly present in all ThDP-dependent decarboxylases; thus its inclusion in our understanding of general thiamin catalysis is important.

  6. Chemical Genomic Screening of a Saccharomyces cerevisiae Genomewide Mutant Collection Reveals Genes Required for Defense against Four Antimicrobial Peptides Derived from Proteins Found in Human Saliva

    Science.gov (United States)

    Bhatt, Sanjay; Schoenly, Nathan E.; Lee, Anna Y.; Nislow, Corey; Bobek, Libuse A.

    2013-01-01

    To compare the effects of four antimicrobial peptides (MUC7 12-mer, histatin 12-mer, cathelicidin KR20, and a peptide containing lactoferricin amino acids 1 to 11) on the yeast Saccharomyces cerevisiae, we employed a genomewide fitness screen of combined collections of mutants with homozygous deletions of nonessential genes and heterozygous deletions of essential genes. When an arbitrary fitness score cutoffs of 1 (indicating a fitness defect, or hypersensitivity) and −1 (indicating a fitness gain, or resistance) was used, 425 of the 5,902 mutants tested exhibited altered fitness when treated with at least one peptide. Functional analysis of the 425 strains revealed enrichment among the identified deletions in gene groups associated with the Gene Ontology (GO) terms “ribosomal subunit,” “ribosome biogenesis,” “protein glycosylation,” “vacuolar transport,” “Golgi vesicle transport,” “negative regulation of transcription,” and others. Fitness profiles of all four tested peptides were highly similar, particularly among mutant strains exhibiting the greatest fitness defects. The latter group included deletions in several genes involved in induction of the RIM101 signaling pathway, including several components of the ESCRT sorting machinery. The RIM101 signaling regulates response of yeasts to alkaline and neutral pH and high salts, and our data indicate that this pathway also plays a prominent role in regulating protective measures against all four tested peptides. In summary, the results of the chemical genomic screens of S. cerevisiae mutant collection suggest that the four antimicrobial peptides, despite their differences in structure and physical properties, share many interactions with S. cerevisiae cells and consequently a high degree of similarity between their modes of action. PMID:23208710

  7. Multi-species sequence comparison reveals conservation of ghrelin gene-derived splice variants encoding a truncated ghrelin peptide.

    Science.gov (United States)

    Seim, Inge; Jeffery, Penny L; Thomas, Patrick B; Walpole, Carina M; Maugham, Michelle; Fung, Jenny N T; Yap, Pei-Yi; O'Keeffe, Angela J; Lai, John; Whiteside, Eliza J; Herington, Adrian C; Chopin, Lisa K

    2016-06-01

    The peptide hormone ghrelin is a potent orexigen produced predominantly in the stomach. It has a number of other biological actions, including roles in appetite stimulation, energy balance, the stimulation of growth hormone release and the regulation of cell proliferation. Recently, several ghrelin gene splice variants have been described. Here, we attempted to identify conserved alternative splicing of the ghrelin gene by cross-species sequence comparisons. We identified a novel human exon 2-deleted variant and provide preliminary evidence that this splice variant and in1-ghrelin encode a C-terminally truncated form of the ghrelin peptide, termed minighrelin. These variants are expressed in humans and mice, demonstrating conservation of alternative splicing spanning 90 million years. Minighrelin appears to have similar actions to full-length ghrelin, as treatment with exogenous minighrelin peptide stimulates appetite and feeding in mice. Forced expression of the exon 2-deleted preproghrelin variant mirrors the effect of the canonical preproghrelin, stimulating cell proliferation and migration in the PC3 prostate cancer cell line. This is the first study to characterise an exon 2-deleted preproghrelin variant and to demonstrate sequence conservation of ghrelin gene-derived splice variants that encode a truncated ghrelin peptide. This adds further impetus for studies into the alternative splicing of the ghrelin gene and the function of novel ghrelin peptides in vertebrates.

  8. Peptide microarray analysis of substrate specificity of the transmembrane Ser/Thr kinase KPI-2 reveals reactivity with cystic fibrosis transmembrane conductance regulator and phosphorylase.

    Science.gov (United States)

    Wang, Hong; Brautigan, David L

    2006-11-01

    Human lemur (Lmr) kinases are predicted to be Tyr kinases based on sequences and are related to neurotrophin receptor Trk kinases. This study used homogeneous recombinant KPI-2 (Lmr2, LMTK2, Cprk, brain-enriched protein kinase) kinase domain and a library of 1,154 peptides on a microarray to analyze substrate specificity. We found that KPI-2 is strictly a Ser/Thr kinase that reacts with Ser either preceded by or followed by Pro residues but unlike other Pro-directed kinases does not strictly require an adjacent Pro residue. The most reactive peptide in the library corresponds to Ser-737 of cystic fibrosis transmembrane conductance regulator, and the recombinant R domain of cystic fibrosis transmembrane conductance regulator was a preferred substrate. Furthermore the KPI-2 kinase phosphorylated peptides corresponding to the single site in phosphorylase and purified phosphorylase b, making this only the second known phosphorylase b kinase. Phosphorylase was used as a specific substrate to show that KPI-2 is inhibited in living cells by addition of nerve growth factor or serum. The results demonstrate the utility of the peptide library to probe specificity and discover kinase substrates and offer a specific assay that reveals hormonal regulation of the activity of this unusual transmembrane kinase.

  9. Insights into the Quorum Sensing Regulon of the Acidophilic Acidithiobacillus ferrooxidans Revealed by Transcriptomic in the Presence of an Acyl Homoserine Lactone Superagonist Analogue

    Directory of Open Access Journals (Sweden)

    Sigde Mamani

    2016-09-01

    Full Text Available While a functional quorum sensing system has been identified in the acidophilic chemolithoautotroph Acidithiobacillus ferrooxidans ATCC 23270T and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in At. ferrooxidansT, the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic superagonist AHL analogue has been studied. First, the effect on biofilm formation of a synthetic AHL tetrazolic analogue, tetrazole 9c, known for its agonistic QS activity, was assessed by fluorescence and electron microscopy experiments. A faster adherence of At. ferrooxidansT cells on sulfur coupons was observed. Then, tetrazole 9c was used in DNA microarray experiments that allowed the identification of genes regulated by quorum sensing signalling, and more particularly, those involved in early biofilm formation. Interestingly, afeI gene, encoding the AHL synthase, but not the At. ferrooxidans quorum sensing transcriptional regulator AfeR encoding gene, was shown to be regulated by quorum sensing. Data indicated that QS network represents at least 4.5 % (141 genes of the ATCC 23270T genome of which 42.5 % (60 genes are related to biofilm formation. Finally, AfeR was shown to bind specifically to the regulatory region of the afeI gene at the level of the palindromic sequence predicted to be the AfeR binding site. Our results give new insights on the response of At. ferrooxidans to quorum sensing and on biofilm biogenesis, opening new biological/chemical alternatives for bioleaching development and managing acid Mine/Rock drainage environmental damages.

  10. In-Depth Glyco-Peptidomics Approach Reveals Unexpected Diversity of Glycosylated Peptides and Atypical Post-Translational Modifications in Dendroaspis angusticeps Snake Venom.

    Science.gov (United States)

    Degueldre, Michel; Echterbille, Julien; Smargiasso, Nicolas; Damblon, Christian; Gouin, Charlotte; Mourier, Gilles; Gilles, Nicolas; De Pauw, Edwin; Quinton, Loïc

    2017-11-18

    Animal venoms represent a valuable source of bioactive peptides that can be derived into useful pharmacological tools, or even innovative drugs. In this way, the venom of Dendroaspis angusticeps (DA), the Eastern Green Mamba, has been intensively studied during recent years. It mainly contains hundreds of large toxins from 6 to 9 kDa, each displaying several disulfide bridges. These toxins are the main target of venom-based studies due to their valuable activities obtained by selectively targeting membrane receptors, such as ion channels or G-protein coupled receptors. This study aims to demonstrate that the knowledge of venom composition is still limited and that animal venoms contain unexpected diversity and surprises. A previous study has shown that Dendroaspis angusticeps venom contains not only a cocktail of classical toxins, but also small glycosylated peptides. Following this work, a deep exploration of DA glycopeptidome by a dual nano liquid chromatography coupled to electrospray ionization mass spectrometry (nanoLC-ESI-MS) and Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) analyses was initiated. This study reveals unsuspected structural diversity of compounds such as 221 glycopeptides, displaying different glycan structures. Sequence alignments underline structural similarities with natriuretic peptides already characterized in Elapidae venoms. Finally, the presence of an S -cysteinylation and hydroxylation of proline on four glycopeptides, never described to date in snake venoms, is also revealed by proteomics and affined by nuclear magnetic resonance (NMR) experiments.

  11. In-Depth Glyco-Peptidomics Approach Reveals Unexpected Diversity of Glycosylated Peptides and Atypical Post-Translational Modifications in Dendroaspis angusticeps Snake Venom

    Directory of Open Access Journals (Sweden)

    Michel Degueldre

    2017-11-01

    Full Text Available Animal venoms represent a valuable source of bioactive peptides that can be derived into useful pharmacological tools, or even innovative drugs. In this way, the venom of Dendroaspis angusticeps (DA, the Eastern Green Mamba, has been intensively studied during recent years. It mainly contains hundreds of large toxins from 6 to 9 kDa, each displaying several disulfide bridges. These toxins are the main target of venom-based studies due to their valuable activities obtained by selectively targeting membrane receptors, such as ion channels or G-protein coupled receptors. This study aims to demonstrate that the knowledge of venom composition is still limited and that animal venoms contain unexpected diversity and surprises. A previous study has shown that Dendroaspis angusticeps venom contains not only a cocktail of classical toxins, but also small glycosylated peptides. Following this work, a deep exploration of DA glycopeptidome by a dual nano liquid chromatography coupled to electrospray ionization mass spectrometry (nanoLC-ESI-MS and Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS analyses was initiated. This study reveals unsuspected structural diversity of compounds such as 221 glycopeptides, displaying different glycan structures. Sequence alignments underline structural similarities with natriuretic peptides already characterized in Elapidae venoms. Finally, the presence of an S-cysteinylation and hydroxylation of proline on four glycopeptides, never described to date in snake venoms, is also revealed by proteomics and affined by nuclear magnetic resonance (NMR experiments.

  12. Influence of turn (or fold) and local charge in fragmentation of the peptide analogue molecule CH3CO-Gly-NH2 following single-photon VUV (118.22 nm) ionization.

    Science.gov (United States)

    Bhattacharya, Atanu; Bernstein, Elliot R

    2011-10-06

    The radical cationic reactivity of the peptide analogue molecule CH(3)CO-Gly-NH(2) is addressed both experimentally and theoretically. The radical cation intermediate of CH(3)CO-Gly-NH(2) is created by single-photon ionization of this molecule at 118.22 nm (~10.5 eV). The two most stable conformers (C(7) and C(5)) of this molecule exhibit different folds along the backbone: the C(7) conformer has a γ-turn structure, and the C(5) conformer has a β-strand structure. The experimental results show that the radical cation intermediate of CH(3)CO-Gly-NH(2) dissociates and generates a fragment-ion signal at 73 amu that is observed through TOFMS. Theoretical results show how the fragment-ion signal at 73 amu is generated by only one conformer of CH(3)CO-Gly-NH(2) (C(7)) and how local charge and specific hydrogen bonding in the molecule influence fragmentation of the radical cation intermediate of CH(3)CO-Gly-NH(2). The specific fold of the molecule controls fragmentation of this reactive radical cation intermediate. Whereas the radical cation of the C(7) conformer dissociates through a hydrogen-transfer mechanism followed by HNCO elimination, the radical cation of the C(5) conformer does not dissociate at all. CASSCF calculations show that positive charge in the radical cationic C(7) conformer is localized at the NH(2)CO moiety of the molecular ion. This site-specific localization of the positive charge enhances the acidity of the terminal NH(2) group, facilitating hydrogen transfer from the NH(2) to the COCH(3) end of the molecular ion. Positive charge in the C(5) conformer of the CH(3)CO-Gly-NH(2) radical cation is, however, localized at the COCH(3) end of the molecular ion, and this conformer does not have enough energy to surmount the energy barrier to dissociation on the ion potential energy surface. CASSCF results show that conformation-specific localization of charge in the CH(3)CO-Gly-NH(2) molecular ion occurs as a result of the different hydrogen

  13. Comparative proteomics reveals that YK51, a 4-Hydroxypandurantin-A analogue, downregulates the expression of proteins associated with dengue virus infection

    Directory of Open Access Journals (Sweden)

    Wei-Lian Tan

    2018-01-01

    Full Text Available Dengue is endemic throughout tropical and subtropical regions of the world. Currently, there is no clinically approved therapeutic drug available for this acute viral infection. Although the first dengue vaccine Dengvaxia has been approved for use in certain countries, it is limited to those without a previous dengue infection while the safety and efficacy of the vaccine in those elderly and younger children still need to be identified. Therefore, it is becoming increasingly important to develop therapeutics/drugs to combat dengue virus (DENV infection. YK51 is a synthetic analogue of 4-Hydroxypandurantin A (a compound found in the crude extract of the rhizomes of Boesenbergia rotunda that has been extensively studied by our research group. It has been shown to possess outstanding antiviral activity due to its inhibitory activity against NS2B/NS3 DENV2 protease. However, it is not known how YK51 affects the proteome of DENV infected cells. Therefore, we performed a comparative proteomics analysis to identify changes in protein expression in DENV infected HepG2 cells treated with YK51. Classical two-dimensional gel electrophoresis followed by protein identification using tandem mass spectrometry was employed in this study. Thirty proteins were found to be down-regulated with YK51 treatment. In silico analysis predicted that the down-regulation of eight of these proteins may inhibit viral infection. Our results suggested that apart from inhibiting the NS2B/NS3 DENV2 protease, YK51 may also be causing the down-regulation of a number of proteins that may be responsible in, and/or essential to virus infection. However, functional characterization of these proteins will be necessary before we can conclusively determine their roles in DENV infection.

  14. Comparative proteomics reveals that YK51, a 4-Hydroxypandurantin-A analogue, downregulates the expression of proteins associated with dengue virus infection.

    Science.gov (United States)

    Tan, Wei-Lian; Lee, Yean Kee; Ho, Yen Fong; Yusof, Rohana; Abdul Rahman, Noorsaadah; Karsani, Saiful Anuar

    2018-01-01

    Dengue is endemic throughout tropical and subtropical regions of the world. Currently, there is no clinically approved therapeutic drug available for this acute viral infection. Although the first dengue vaccine Dengvaxia has been approved for use in certain countries, it is limited to those without a previous dengue infection while the safety and efficacy of the vaccine in those elderly and younger children still need to be identified. Therefore, it is becoming increasingly important to develop therapeutics/drugs to combat dengue virus (DENV) infection. YK51 is a synthetic analogue of 4-Hydroxypandurantin A (a compound found in the crude extract of the rhizomes of Boesenbergia rotunda ) that has been extensively studied by our research group. It has been shown to possess outstanding antiviral activity due to its inhibitory activity against NS2B/NS3 DENV2 protease. However, it is not known how YK51 affects the proteome of DENV infected cells. Therefore, we performed a comparative proteomics analysis to identify changes in protein expression in DENV infected HepG2 cells treated with YK51. Classical two-dimensional gel electrophoresis followed by protein identification using tandem mass spectrometry was employed in this study. Thirty proteins were found to be down-regulated with YK51 treatment. In silico analysis predicted that the down-regulation of eight of these proteins may inhibit viral infection. Our results suggested that apart from inhibiting the NS2B/NS3 DENV2 protease, YK51 may also be causing the down-regulation of a number of proteins that may be responsible in, and/or essential to virus infection. However, functional characterization of these proteins will be necessary before we can conclusively determine their roles in DENV infection.

  15. Adrenaline modulates the global transcriptional profile of Salmonella revealing a role in the antimicrobial peptide and oxidative stress resistance responses

    Directory of Open Access Journals (Sweden)

    Williams P

    2008-10-01

    Full Text Available Abstract Background The successful interaction of bacterial pathogens with host tissues requires the sensing of specific chemical and physical cues. The human gut contains a huge number of neurons involved in the secretion and sensing of a class of neuroendocrine hormones called catecholamines. Recently, in Escherichia coli O157:H7, the catecholamines adrenaline and noradrenaline were shown to act synergistically with a bacterial quorum sensing molecule, autoinducer 3 (AI-3, to affect bacterial virulence and motility. We wished to investigate the impact of adrenaline on the biology of Salmonella spp. Results We have determined the effect of adrenaline on the transcriptome of the gut pathogen Salmonella enterica serovar Typhimurium. Addition of adrenaline led to an induction of key metal transport systems within 30 minutes of treatment. The oxidative stress responses employing manganese internalisation were also elicited. Cells lacking the key oxidative stress regulator OxyR showed reduced survival in the presence of adrenaline and complete restoration of growth upon addition of manganese. A significant reduction in the expression of the pmrHFIJKLM antimicrobial peptide resistance operon reduced the ability of Salmonella to survive polymyxin B following addition of adrenaline. Notably, both phenotypes were reversed by the addition of the β-adrenergic blocker propranolol. Our data suggest that the BasSR two component signal transduction system is the likely adrenaline sensor mediating the antimicrobial peptide response. Conclusion Salmonella are able to sense adrenaline and downregulate the antimicrobial peptide resistance pmr locus through the BasSR two component signalling system. Through iron transport, adrenaline may affect the oxidative stress balance of the cell requiring OxyR for normal growth. Both adrenaline effects can be inhibited by the addition of the β-adrenergic blocker propranolol. Adrenaline sensing may provide an environmental

  16. Mining for Nonribosomal Peptide Synthetase and Polyketide Synthase Genes Revealed a High Level of Diversity in the Sphagnum Bog Metagenome.

    Science.gov (United States)

    Müller, Christina A; Oberauner-Wappis, Lisa; Peyman, Armin; Amos, Gregory C A; Wellington, Elizabeth M H; Berg, Gabriele

    2015-08-01

    Sphagnum bog ecosystems are among the oldest vegetation forms harboring a specific microbial community and are known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome shows a rich secondary metabolism, the genes have not yet been explored. To analyze nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), the diversity of NRPS and PKS genes in Sphagnum-associated metagenomes was investigated by in silico data mining and sequence-based screening (PCR amplification of 9,500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPSs and 346 PKSs, as well as 40 PKS-NRPS hybrid gene sequences. The occurrence of NRPS sequences was strongly dominated by the members of the Protebacteria phylum, especially by species of the Burkholderia genus, while PKS sequences were mainly affiliated with Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR amplification screening, displaying amino acid identities of 48% to 91% to annotated sequences of members of the phyla Proteobacteria, Actinobacteria, and Cyanobacteria. Some of the identified metagenomic clones showed the closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of as-yet-undescribed bioactive metabolites. This report highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Fecal Gluten Peptides Reveal Limitations of Serological Tests and Food Questionnaires for Monitoring Gluten-Free Diet in Celiac Disease Patients

    Science.gov (United States)

    Comino, Isabel; Fernández-Bañares, Fernando; Esteve, María; Ortigosa, Luís; Castillejo, Gemma; Fambuena, Blanca; Ribes-Koninckx, Carmen; Sierra, Carlos; Rodríguez-Herrera, Alfonso; Salazar, José Carlos; Caunedo, Ángel; Marugán-Miguelsanz, J M; Garrote, José Antonio; Vivas, Santiago; lo Iacono, Oreste; Nuñez, Alejandro; Vaquero, Luis; Vegas, Ana María; Crespo, Laura; Fernández-Salazar, Luis; Arranz, Eduardo; Jiménez-García, Victoria Alejandra; Antonio Montes-Cano, Marco; Espín, Beatriz; Galera, Ana; Valverde, Justo; Girón, Francisco José; Bolonio, Miguel; Millán, Antonio; Cerezo, Francesc Martínez; Guajardo, César; Alberto, José Ramón; Rosinach, Mercé; Segura, Verónica; León, Francisco; Marinich, Jorge; Muñoz-Suano, Alba; Romero-Gómez, Manuel; Cebolla, Ángel; Sousa, Carolina

    2016-01-01

    Objectives: Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring. Methods: We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously. Results: Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ≥13 years old) and with gender in certain age groups (60% in men ≥13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP. Conclusions: Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397. PMID:27644734

  18. Analogue MIMO Detection

    Directory of Open Access Journals (Sweden)

    McNamara Darren

    2006-01-01

    Full Text Available In this contribution we propose an analogue receiver that can perform turbo detection in MIMO systems. We present the case for a receiver that is built from nonlinear analogue devices, which perform detection in a "free-flow" network (no notion of iterations. This contribution can be viewed as an extension of analogue turbo decoder concepts to include MIMO detection. These first analogue implementations report reductions of few orders of magnitude in the number of required transistors and in consumed energy, and the same order of improvement in processing speed. It is anticipated that such analogue MIMO decoder could bring about the same advantages, when compared to traditional digital implementations.

  19. IgV peptide mapping of native Ro60 autoantibody proteomes in primary Sjögren's syndrome reveals molecular markers of Ro/La diversification.

    Science.gov (United States)

    Wang, Jing J; Al Kindi, Mahmood A; Colella, Alex D; Dykes, Lukah; Jackson, Michael W; Chataway, Tim K; Reed, Joanne H; Gordon, Tom P

    2016-12-01

    We have used high-resolution mass spectrometry to sequence precipitating anti-Ro60 proteomes from sera of patients with primary Sjögren's syndrome and compare immunoglobulin variable-region (IgV) peptide signatures in Ro/La autoantibody subsets. Anti-Ro60 were purified by elution from native Ro60-coated ELISA plates and subjected to combined de novo amino acid sequencing and database matching. Monospecific anti-Ro60 Igs comprised dominant public and minor private sets of IgG1 kappa and lambda restricted heavy and light chains. Specific IgV amino acid substitutions stratified anti-Ro60 from anti-Ro60/La responses, providing a molecular fingerprint of Ro60/La determinant spreading and suggesting that different forms of Ro60 antigen drive these responses. Sequencing of linked anti-Ro52 proteomes from individual patients and comparison with their anti-Ro60 partners revealed sharing of a dominant IGHV3-23/IGKV3-20 paired clonotype but with divergent IgV mutational signatures. In summary, anti-Ro60 IgV peptide mapping provides insights into Ro/La autoantibody diversification and reveals serum-based molecular markers of humoral Ro60 autoimmunity. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Characterizing the structure-function relationship reveals the mode of action of a novel antimicrobial peptide, P1, from jumper ant Myrmecia pilosula.

    Science.gov (United States)

    Tseng, Tien-Sheng; Tsai, Keng-Chang; Chen, Chinpan

    2017-06-01

    Microbial infections of antibiotic-resistant strains cause serious diseases and have a significant impact on public health worldwide, so novel antimicrobial drugs are urgently needed. Insect venoms, a rich source of bioactive components containing antimicrobial peptides (AMPs), are attractive candidates for new therapeutic agents against microbes. Recently, a novel peptide, P1, identified from the venom of the Australian jumper ant Myrmecia pilosula, showed potent antimicrobial activities against both Gram-negative and Gram-positive bacteria, but its structure-function relationship is unknown. Here, we used biochemical and biophysical techniques coupled with computational simulations to explore the mode of action of P1 interaction with dodecylphosphocholine (DPC) micelles as a model membrane system. Our circular dichroism (CD) and NMR studies revealed an amphipathic α-helical structure for P1 upon interaction with DPC micelles. A paramagnetic relaxation enhancement approach revealed that P1 orients its α-helix segment (F6-G14) into DPC micelles. In addition, the α-helix segment could be essential for membrane permeabilization and antimicrobial activity. Moreover, the arginine residues R8, R11, and R15 significantly contribute to helix formation and membrane-binding affinity. The lysine residue K19 of the C-terminus functionally guides P1 to interact with DPC micelles in the early interaction stage. Our study provides insights into the mode of action of P1, which is valuable in modifying and developing potent AMPs as antibiotic drugs.

  1. Homology-guided mutational analysis reveals the functional requirements for antinociceptive specificity of collapsin response mediator protein 2-derived peptides.

    Science.gov (United States)

    Moutal, Aubin; Li, Wennan; Wang, Yue; Ju, Weina; Luo, Shizhen; Cai, Song; François-Moutal, Liberty; Perez-Miller, Samantha; Hu, Jackie; Dustrude, Erik T; Vanderah, Todd W; Gokhale, Vijay; Khanna, May; Khanna, Rajesh

    2017-02-05

    N-type voltage-gated calcium (Ca v 2.2) channels are critical determinants of increased neuronal excitability and neurotransmission accompanying persistent neuropathic pain. Although Ca v 2.2 channel antagonists are recommended as first-line treatment for neuropathic pain, calcium-current blocking gabapentinoids inadequately alleviate chronic pain symptoms and often exhibit numerous side effects. Collapsin response mediator protein 2 (CRMP2) targets Ca v 2.2 channels to the sensory neuron membrane and allosterically modulates their function. A 15-amino-acid peptide (CBD3), derived from CRMP2, disrupts the functional protein-protein interaction between CRMP2 and Ca v 2.2 channels to inhibit calcium influx, transmitter release and acute, inflammatory and neuropathic pain. Here, we have mapped the minimal domain of CBD3 necessary for its antinociceptive potential. Truncated as well as homology-guided mutant versions of CBD3 were generated and assessed using depolarization-evoked calcium influx in rat dorsal root ganglion neurons, binding between CRMP2 and Ca v 2.2 channels, whole-cell voltage clamp electrophysiology and behavioural effects in two models of experimental pain: post-surgical pain and HIV-induced sensory neuropathy induced by the viral glycoprotein 120. The first six amino acids within CBD3 accounted for all in vitro activity and antinociception. Spinal administration of a prototypical peptide (TAT-CBD3-L5M) reversed pain behaviours. Homology-guided mutational analyses of these six amino acids identified at least two residues, Ala1 and Arg4, as being critical for antinociception in two pain models. These results identify an antinociceptive scaffold core in CBD3 that can be used for development of low MW mimetics of CBD3. © 2017 The British Pharmacological Society.

  2. Preparation and Evaluation at the Delta Opioid Receptor of a Series of Linear Leu-Enkephalin Analogues Obtained by Systematic Replacement of the Amides

    Science.gov (United States)

    2013-01-01

    Leu-enkephalin analogues, in which the amide bonds were sequentially and systematically replaced either by ester or N-methyl amide bonds, were prepared using classical organic chemistry as well as solid phase peptide synthesis (SPPS). The peptidomimetics were characterized using competition binding, ERK1/2 phosphorylation, receptor internalization, and contractility assays to evaluate their pharmacological profile over the delta opioid receptor (DOPr). The lipophilicity (LogD7.4) and plasma stability of the active analogues were also measured. Our results revealed that the last amide bond can be successfully replaced by either an ester or an N-methyl amide bond without significantly decreasing the biological activity of the corresponding analogues when compared to Leu-enkephalin. The peptidomimetics with an N-methyl amide function between residues Phe and Leu were found to be more lipophilic and more stable than Leu-enkephalin. Findings from the present study further revealed that the hydrogen-bond donor properties of the fourth amide of Leu-enkephalin are not important for its biological activity on DOPr. Our results show that the systematic replacement of amide bonds by isosteric functions represents an efficient way to design and synthesize novel peptide analogues with enhanced stability. Our findings further suggest that such a strategy can also be useful to study the biological roles of amide bonds. PMID:23650868

  3. Structural and pharmacological characteristics of chimeric peptides derived from peptide E and beta-endorphin reveal the crucial role of the C-terminal YGGFL and YKKGE motifs in their analgesic properties.

    Science.gov (United States)

    Condamine, Eric; Courchay, Karine; Rego, Jean-Claude Do; Leprince, Jérôme; Mayer, Catherine; Davoust, Daniel; Costentin, Jean; Vaudry, Hubert

    2010-05-01

    Peptide E (a 25-amino acid peptide derived from proenkephalin A) and beta-endorphin (a 31-amino acid peptide derived from proopiomelanocortin) bind with high affinity to opioid receptors and share structural similarities but induce analgesic effects of very different intensity. Indeed, whereas they possess the same N-terminus Met-enkephalin message sequence linked to a helix by a flexible spacer and a C-terminal part in random coil conformation, in contrast with peptide E, beta-endorphin produces a profound analgesia. To determine the key structural elements explaining this very divergent opioid activity, we have compared the structural and pharmacological characteristics of several chimeric peptides derived from peptide E and beta-endorphin. Structures were obtained under the same experimental conditions using circular dichroism, computational estimation of helical content and/or nuclear magnetic resonance spectroscopy (NMR) and NMR-restrained molecular modeling. The hot-plate and writhing tests were used in mice to evaluate the antinociceptive effects of the peptides. Our results indicate that neither the length nor the physicochemical profile of the spacer plays a fundamental role in analgesia. On the other hand, while the functional importance of the helix cannot be excluded, the last 5 residues in the C-terminal part seem to be crucial for the expression or absence of the analgesic activity of these peptides. These data raise the question of the true function of peptides E in opioidergic systems. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  4. Conformational Plasticity of the Cell-Penetrating Peptide SAP As Revealed by Solid-State 19F-NMR and Circular Dichroism Spectroscopies.

    Science.gov (United States)

    Afonin, Sergii; Kubyshkin, Vladimir; Mykhailiuk, Pavel K; Komarov, Igor V; Ulrich, Anne S

    2017-07-13

    The cell-penetrating peptide SAP, which was designed as an amphipathic poly-l-proline helix II (PPII), was suggested to self-assemble into regular fibrils that are relevant for its internalization. Herein we have analyzed the structure of SAP in the membrane-bound state by solid-state 19 F-NMR, which revealed other structural states, in addition to the expected surface-aligned PPII. Trifluoromethyl-bicyclopentyl-glycine (CF 3 -Bpg) and two rigid isomers of trifluoromethyl-4,5-methanoprolines (CF 3 -MePro) were used as labels for 19 F-NMR analysis. The equilibria between different conformations of SAP were studied and were found to be shifted by the substituents at Pro-11. Synchrotron-CD results suggested that substituting Pro-11 by CF 3 -MePro governed the coil-to-PPII equilibrium in solution and in the presence of a lipid bilayer. Using CD and 19 F-NMR, we examined the slow kinetics of the association of SAP with membranes and the dependence of the SAP conformational dynamics on the lipid composition. The peptide did not bind to lipids in the solid ordered phase and aggregated only in the liquid ordered "raft"-like bilayers. Self-association could not be detected in solution or in the presence of liquid disordered membranes. Surface-bound amphipathic SAP in a nonaggregated state was structured as a mixture of nonideal extended conformations reflecting the equilibrium already present in solution, i.e., before binding to the membrane.

  5. Synthetic histatin analogues with broad-spectrum antimicrobial activity.

    OpenAIRE

    Helmerhorst, E J; Van't Hof, W; Veerman, E C; Simoons-Smit, I; Nieuw Amerongen, A V

    1997-01-01

    Histatins are salivary histidine-rich cationic peptides, ranging from 7 to 38 amino acid residues in length, that exert a potent killing effect in vitro on Candida albicans. Starting from the C-terminal fungicidal domain of histatin 5 (residues 11-24, called dh-5) a number of substitution analogues were chemically synthesized to study the effect of amphipathicity of the peptide in helix conformation on candidacidal activity. Single substitutions in dh-5 at several positions did not have any e...

  6. Kahalalide F analogues from the mucous secretion of Indian sacoglossan mollusc Elysia ornata

    Digital Repository Service at National Institute of Oceanography (India)

    Ciavatta, M.L.; PrabhaDevi; Carbone, M.; Mathieu, V.; Kiss, R.; Casapullo, A.; Gavagnin, M.

    , better delivery, or longer half-life. More than 150 analogues were obtained by solid phase peptide synthesis8,9 and more recently a semi-synthetic approach to produce KF analogues starting from natural KF has been also performed.10In parallel...

  7. Analogue circuits simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mendo, C

    1988-09-01

    Most analogue simulators have evolved from SPICE. The history and description of SPICE-like simulators are given. From a mathematical formulation of the electronic circuit the following analysis are possible: DC, AC, transient, noise, distortion, Worst Case and Statistical.

  8. 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

  9. Evaluation of the antibacterial spectrum of drosocin analogues

    NARCIS (Netherlands)

    Bikker, F.J.; Kaman-van Zanten, W.E.; Vries-van de Ruit, A.M.B.C. de; Voskamp-Visser, I.; Hooft, P.A.V. van; Mars-Groenendijk, R.H.; Visser, P.C. de; Noort, D.

    2006-01-01

    Drosocin is a 19-mer, cationic antimicrobial peptide from Drosophila melanogaster. The aim of the study was to examine the antibacterial spectrum of unglycosylated drosocin analogues. Furthermore, the amino acid sequence of DnaK, drosocin's intracellular target, from susceptible species was aligned

  10. Synthesis and biological evaluation of novel gramicidin s analogues

    NARCIS (Netherlands)

    Tuin, A.W.; Palachanis, D.K.; Buizert, A.; Grotenbreg, G.M.; Spalburg, E.; Neeling, A.J. de; Mars-Groenendijk, R.H.; Noort, D.; Marel, G.A. van der; Overkleeft, H.S.; Overhand, M.

    2009-01-01

    The synthesis of three new analogues of the cyclic cationic antimicrobial peptide Gramicidin S is described. These derivatives contain a modified turn region in which the DPhe-Pro motif has been replaced by a constrained furanoid sugar amino acid or a flexible linear aminoethoxy acetic acid moiety.

  11. Truncated Glucagon-like Peptide-1 and Exendin-4 α-Conotoxin pl14a Peptide Chimeras Maintain Potency and α-Helicity and Reveal Interactions Vital for cAMP Signaling in Vitro*

    Science.gov (United States)

    Swedberg, Joakim E.; Schroeder, Christina I.; Mitchell, Justin M.; Fairlie, David P.; Edmonds, David J.; Griffith, David A.; Ruggeri, Roger B.; Derksen, David R.; Loria, Paula M.; Price, David A.; Liras, Spiros; Craik, David J.

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) signaling through the glucagon-like peptide 1 receptor (GLP-1R) is a key regulator of normal glucose metabolism, and exogenous GLP-1R agonist therapy is a promising avenue for the treatment of type 2 diabetes mellitus. To date, the development of therapeutic GLP-1R agonists has focused on producing drugs with an extended serum half-life. This has been achieved by engineering synthetic analogs of GLP-1 or the more stable exogenous GLP-1R agonist exendin-4 (Ex-4). These synthetic peptide hormones share the overall structure of GLP-1 and Ex-4, with a C-terminal helical segment and a flexible N-terminal tail. Although numerous studies have investigated the molecular determinants underpinning GLP-1 and Ex-4 binding and signaling through the GLP-1R, these have primarily focused on the length and composition of the N-terminal tail or on how to modulate the helicity of the full-length peptides. Here, we investigate the effect of C-terminal truncation in GLP-1 and Ex-4 on the cAMP pathway. To ensure helical C-terminal regions in the truncated peptides, we produced a series of chimeric peptides combining the N-terminal portion of GLP-1 or Ex-4 and the C-terminal segment of the helix-promoting peptide α-conotoxin pl14a. The helicity and structures of the chimeric peptides were confirmed using circular dichroism and NMR, respectively. We found no direct correlation between the fractional helicity and potency in signaling via the cAMP pathway. Rather, the most important feature for efficient receptor binding and signaling was the C-terminal helical segment (residues 22–27) directing the binding of Phe22 into a hydrophobic pocket on the GLP-1R. PMID:27226591

  12. Photoaffinity analogues of methotrexate as folate antagonist binding probes. 1. Photoaffinity labeling of murine L1210 dihydrofolate reductase and amino acid sequence of the binding region

    International Nuclear Information System (INIS)

    Price, E.M.; Smith, P.L.; Klein, T.E.; Freisheim, J.H.

    1987-01-01

    N/sup α/-(4-Amino-4-deoxy-10-methylpteroyl)-N/sup epsilon/-(4-azido-5-[ 125 I]iodosalicylyl)-L-lysine, a photoaffinity analogue of methotrexate, is only 2-fold less potent than methotrexate in the inhibition of murine L1210 dihydrofolate reductase. Irradiation of the enzyme in the presence of an equimolar concentration of the 125 I-labeled analogue ultimately leads to an 8% incorporation of the photoprobe. A 100-fold molar excess of methotrexate essentially blocks this incorporation. Cyanogen bromide digestion of the labeled enzyme, followed by high-pressure liquid chromatography purification of the generated peptides, indicates that greater than 85% of the total radioactivity is incorporated into a single cyanogen bromide peptide. Sequence analysis revealed this peptide to be residues 53-111, with a majority of the radioactivity centered around residues 63-65 (Lys-Asn-Arg). These data demonstrate that the photoaffinity analogue specifically binds to dihydrofolate reductase and covalently modifies the enzyme following irradiation and is therefore a photolabeling agent useful for probing the inhibitor binding domain of the enzyme

  13. Nonribosomal biosynthesis of backbone-modified peptides

    Science.gov (United States)

    Niquille, David L.; Hansen, Douglas A.; Mori, Takahiro; Fercher, David; Kries, Hajo; Hilvert, Donald

    2018-03-01

    Biosynthetic modification of nonribosomal peptide backbones represents a potentially powerful strategy to modulate the structure and properties of an important class of therapeutics. Using a high-throughput assay for catalytic activity, we show here that an L-Phe-specific module of an archetypal nonribosomal peptide synthetase can be reprogrammed to accept and process the backbone-modified amino acid (S)-β-Phe with near-native specificity and efficiency. A co-crystal structure with a non-hydrolysable aminoacyl-AMP analogue reveals the origins of the 40,000-fold α/β-specificity switch, illuminating subtle but precise remodelling of the active site. When the engineered catalyst was paired with downstream module(s), (S)-β-Phe-containing peptides were produced at preparative scale in vitro (~1 mmol) and high titres in vivo (~100 mg l-1), highlighting the potential of biosynthetic pathway engineering for the construction of novel nonribosomal β-frameworks.

  14. Detection of gluten immunogenic peptides in the urine of patients with coeliac disease reveals transgressions in the gluten-free diet and incomplete mucosal healing.

    Science.gov (United States)

    Moreno, María de Lourdes; Cebolla, Ángel; Muñoz-Suano, Alba; Carrillo-Carrion, Carolina; Comino, Isabel; Pizarro, Ángeles; León, Francisco; Rodríguez-Herrera, Alfonso; Sousa, Carolina

    2017-02-01

    Gluten-free diet (GFD) is the only management for coeliac disease (CD). Available methods to assess GFD compliance are insufficiently sensitive to detect occasional dietary transgressions that may cause gut mucosal damage. We aimed to develop a method to determine gluten intake and monitor GFD compliance in patients with CD and to evaluate its correlation with mucosal damage. Urine samples of 76 healthy subjects and 58 patients with CD subjected to different gluten dietary conditions were collected. A lateral flow test (LFT) with the highly sensitive and specific G12 monoclonal antibody for the most dominant gluten immunogenic peptides (GIP) and a LFT reader were used to quantify GIP in solid-phase extracted urines. GIP were detectable in concentrated urines from healthy individuals previously subjected to GFD as early as 4-6 h after single gluten intake, and remained detectable for 1-2 days. The urine assay revealed infringement of the GFD in about 50% of the patients. Analysis of duodenal biopsies revealed that most of patients with CD (89%) with no villous atrophy had no detectable GIP in urine, while all patients with quantifiable GIP in urine showed incomplete intestinal mucosa recovery. GIP are detected in urine after gluten consumption, enabling a new and non-invasive method to monitor GFD compliance and transgressions. The method was sensitive, specific and simple enough to be convenient for clinical monitoring of patients with CD as well as for basic and clinical research applications including drug development. NCT02344758. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  15. What peptides these deltorphins be.

    Science.gov (United States)

    Lazarus, L H; Bryant, S D; Cooper, P S; Salvadori, S

    1999-02-01

    The deltorphins are a class of highly selective delta-opioid heptapeptides from the skin of the Amazonian frogs Phyllomedusa sauvagei and P. bicolor. The first of these fascinating peptides came to light in 1987 by cloning of the cDNA of from frog skins, while the other members of this family were identified either by cDNA or isolation of the peptides. The distinctive feature of deltorphins is the presence of a naturally occurring D-enantiomer at the second position in their common N-terminal sequence, Tyr-D-Xaa-Phe, comparable to dermorphin, which is the prototype of a group of mu-selective opioids from the same source. The D-amino acid and the anionic residues, either Glu or Asp, as well as their unique amino acid compositions are responsible for the remarkable biostability, high delta-receptor affinity, bioactivity and peptide conformation. This review summarizes a decade of research from many laboratories that defined which residues and substituents in the deltorphins interact with the delta-receptor and characterized pharmacological and physiological activities in vitro and in vivo. It begins with a historical description of the topic and presents general schema for the synthesis of peptide analogues of deltorphins A, B and C as a means to document the methods employed in producing a myriad of analogues. Structure activity studies of the peptides and their pharmacological activities in vitro are detailed in abundantly tabulated data. A brief compendium of the current level of knowledge of the delta-receptor assists the reader to appreciate the rationale for the design of these analogues. Discussion of the conformation of these peptides addresses how structure leads to further hypotheses regarding ligand receptor interaction. The review ends with a broad discussion of the potential applications of these peptides in clinical and therapeutic settings.

  16. Dual activation of pathways regulated by steroid receptors and peptide growth factors in primary prostate cancer revealed by Factor Analysis of microarray data

    Directory of Open Access Journals (Sweden)

    Fernandez Pedro L

    2005-08-01

    Full Text Available Abstract Background We use an approach based on Factor Analysis to analyze datasets generated for transcriptional profiling. The method groups samples into biologically relevant categories, and enables the identification of genes and pathways most significantly associated to each phenotypic group, while allowing for the participation of a given gene in more than one cluster. Genes assigned to each cluster are used for the detection of pathways predominantly activated in that cluster by finding statistically significant associated GO terms. We tested the approach with a published dataset of microarray experiments in yeast. Upon validation with the yeast dataset, we applied the technique to a prostate cancer dataset. Results Two major pathways are shown to be activated in organ-confined, non-metastatic prostate cancer: those regulated by the androgen receptor and by receptor tyrosine kinases. A number of gene markers (HER3, IQGAP2 and POR1 highlighted by the software and related to the later pathway have been validated experimentally a posteriori on independent samples. Conclusion Using a new microarray analysis tool followed by a posteriori experimental validation of the results, we have confirmed several putative markers of malignancy associated with peptide growth factor signalling in prostate cancer and revealed others, most notably ERRB3 (HER3. Our study suggest that, in primary prostate cancer, HER3, together or not with HER4, rather than in receptor complexes involving HER2, could play an important role in the biology of these tumors. These results provide new evidence for the role of receptor tyrosine kinases in the establishment and progression of prostate cancer.

  17. Cobalamin analogues in humans

    DEFF Research Database (Denmark)

    Hardlei, Tore Forsingdal; Obeid, Rima; Herrmann, Wolfgang

    2013-01-01

    BACKGROUND: Haptocorrin (HC) carries cobalamin analogues (CorA), but whether CorA are produced in the body is unknown. All cobalamins (Cbl) to the foetus are delivered by the Cbl-specific protein transcobalamin (TC), and therefore analysis of cord serum for CorA may help to clarify the origin...

  18. NATURAL ANALOGUE SYNTHESIS REPORT

    International Nuclear Information System (INIS)

    Simmons, A.M.

    2004-01-01

    The purpose of this report is to present analogue studies and literature reviews designed to provide qualitative and quantitative information to test and provide added confidence in process models abstracted for performance assessment (PA) and model predictions pertinent to PA. This report provides updates to studies presented in the Yucca Mountain Site Description (CRWMS M and O 2000 [151945], Section 13) and new examples gleaned from the literature along with results of quantitative studies conducted specifically for the Yucca Mountain Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate additional understanding of processes expected to occur during postclosure at a potential Yucca Mountain repository. The report focuses on key processes by providing observations and analyses of natural and anthropogenic (human-induced) systems to improve understanding and confidence in the operation of these processes under conditions similar to those that could occur in a nuclear waste repository. The process models include those that represent both engineered and natural barrier processes. A second purpose of this report is to document the various applications of natural analogues to geologic repository programs, focusing primarily on the way analogues have been used by the YMP. This report is limited to providing support for PA in a confirmatory manner and to providing corroborative inputs for process modeling activities. Section 1.7 discusses additional limitations of this report. Key topics for this report are analogues to emplacement-drift degradation, waste-form degradation, waste-package degradation, degradation of other materials proposed for the engineered barrier, seepage into drifts, radionuclide flow and transport in the unsaturated zone (UZ), analogues to coupled thermal-hydrologic-mechanical-chemical processes, saturated-zone (SZ) transport, impact of radionuclide release on the biosphere

  19. Natural Analogue Synthesis Report

    Energy Technology Data Exchange (ETDEWEB)

    A. M. Simmons

    2002-05-01

    The purpose of this report is to present analogue studies and literature reviews designed to provide qualitative and quantitative information to test and provide added confidence in process models abstracted for performance assessment (PA) and model predictions pertinent to PA. This report provides updates to studies presented in the ''Yucca Mountain Site Description'' (CRWMS M and O 2000 [151945], Section 13) and new examples gleaned from the literature, along with results of quantitative studies conducted specifically for the Yucca Mountain Site Characterization Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate additional understanding of processes expected to occur during postclosure at a potential Yucca Mountain repository. The report focuses on key processes by providing observations and analyses of natural and anthropogenic (human-induced) systems to improve understanding and confidence in the operation of these processes under conditions similar to those that could occur in a nuclear waste repository. The process models include those that represent both engineered and natural barrier processes. A second purpose of this report is to document the various applications of natural analogues to geologic repository programs, focusing primarily on the way analogues have been used by the YMP. This report is limited to providing support for PA in a confirmatory manner and to providing corroborative inputs for process modeling activities. Section 1.7 discusses additional limitations of this report. Key topics for this report are analogues to emplacement drift degradation, waste form degradation, waste package degradation, degradation of other materials proposed for the engineered barrier, seepage into drifts, radionuclide flow and transport in the unsaturated zone (UZ), analogues to coupled thermal-hydrologic-mechanical-chemical processes, saturated zone (SZ) transport

  20. [Plant signaling peptides. Cysteine-rich peptides].

    Science.gov (United States)

    Ostrowski, Maciej; Kowalczyk, Stanisław

    2015-01-01

    Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

  1. CEC natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1986-01-01

    The second meeting of the CEC Natural Analogue Working Group took place on June 17-19, 1986, hosted by the Swiss NAGRA in Interlaken (CH). A review of recent progress in natural analogue programmes was carried out, and complemented by detailed discussions about geomicrobiology, archaeological analogues, natural colloids, and use of analogues to increase confidence in safety assessments for radioactive waste disposal. A statement drafted by the Group, and the presentations made, are put together in this report

  2. Efficacy of antibacterial peptides against peptide-resistant MRSA is restored by permeabilisation of bacteria membranes

    Directory of Open Access Journals (Sweden)

    Joshua Thomas Ravensdale

    2016-11-01

    Full Text Available Clinical application of antimicrobial peptides, as with conventional antibiotics, may be compromised by the development of bacterial resistance. This study investigated antimicrobial peptide resistance in methicillin resistant Staphylococcus aureus, including aspects related to the resilience of the resistant bacteria towards the peptides, the stability of resistance when selection pressures are removed, and whether resistance can be overcome by using the peptides with other membrane-permeabilising agents. Genotypically variant strains of S. aureus became equally resistant to the antibacterial peptides melittin and bac8c when grown in sub-lethal concentrations. Subculture of a melittin-resistant strain without melittin for 8 days lowered the minimal lethal concentration of the peptide from 170 µg ml-1 to 30 g ml-1. Growth for 24 h in 12 g ml-1 melittin restored the MLC to 100 g ml-1. Flow cytometry analysis of cationic fluorophore binding to melittin-naïve and melittin-resistant bacteria revealed that resistance coincided with decreased binding of cationic molecules, suggesting a reduction in nett negative charge on the membrane. Melittin was haemolytic at low concentrations but the truncated analogue of melittin, mel12-26, was confirmed to lack haemolytic activity. Although a previous report found that mel12-26 retained full bactericidal activity, we found it to lack significant activity when added to culture medium. However, electroporation in the presence of 50 µg ml-1 of mel12-26, killed 99.3% of the bacteria. Similarly, using a low concentration of the non-ionic detergent Triton X-100 to permeabilize bacteria to mel12-26 markedly increased its bactericidal activity. The observation that bactericidal activity of the non-membranolytic peptide mel12-26 was enhanced when the bacterial membrane was permeablised by detergents or electroporation, suggests that its principal mechanism in reducing bacterial survival may be through

  3. Chemical Editing of Macrocyclic Natural Products and Kinetic Profiling Reveal Slow, Tight-Binding Histone Deacetylase Inhibitors with Picomolar Affinities

    DEFF Research Database (Denmark)

    Kitir, Betül; Maolanon, Alex R.; Ohm, Ragnhild G.

    2017-01-01

    medicines. Therefore, detailed mechanistic information and precise characterization of the chemical probes used to investigate the effects of HDAC enzymes are vital. We interrogated Nature's arsenal of macrocyclic nonribosomal peptide HDAC inhibitors by chemical synthesis and evaluation of more than 30...... natural products and analogues. This furnished surprising trends in binding affinities for the various macrocycles, which were then exploited for the design of highly potent class I and IIb HDAC inhibitors. Furthermore, thorough kinetic investigation revealed unexpected inhibitory mechanisms of important...

  4. CEC Natural Analogue Working Group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.A.

    1989-01-01

    The central theme for the third meeting of the CEC analogue working group was ''How can analogue data be used for performance assessments, both in support of the results and for presentation to the public''. This report puts together the most recent achievements in this field, together with a review of on-going natural analogue programmes

  5. Serum reactome induced by Bordetella pertussis infection and Pertussis vaccines: qualitative differences in serum antibody recognition patterns revealed by peptide microarray analysis.

    Science.gov (United States)

    Valentini, Davide; Ferrara, Giovanni; Advani, Reza; Hallander, Hans O; Maeurer, Markus J

    2015-07-01

    Pertussis (whooping cough) remains a public health problem despite extensive vaccination strategies. Better understanding of the host-pathogen interaction and the detailed B. pertussis (Bp) target recognition pattern will help in guided vaccine design. We characterized the specific epitope antigen recognition profiles of serum antibodies ('the reactome') induced by whooping cough and B. pertussis (Bp) vaccines from a case-control study conducted in 1996 in infants enrolled in a Bp vaccine trial in Sweden (Gustafsson, NEJM, 1996, 334, 349-355). Sera from children with whooping cough, vaccinated with Diphtheria Tetanus Pertussis (DTP) whole-cell (wc), acellular 5 (DPTa5), or with the 2 component (a2) vaccines and from infants receiving only DT (n=10 for each group) were tested with high-content peptide microarrays containing 17 Bp proteins displayed as linear (n=3175) peptide stretches. Slides were incubated with serum and peptide-IgG complexes detected with Cy5-labeled goat anti-human IgG and analyzed using a GenePix 4000B microarray scanner, followed by statistical analysis, using PAM (Prediction Analysis for Microarrays) and the identification of uniquely recognized peptide epitopes. 367/3,085 (11.9%) peptides were recognized in 10/10 sera from children with whooping cough, 239 (7.7%) in DTPwc, 259 (8.4%) in DTPa5, 105 (3.4%) DTPa2, 179 (5.8%) in the DT groups. Recognition of strongly recognized peptides was similar between whooping cough and DPTwc, but statistically different between whooping cough vs. DTPa5 (p<0.05), DTPa2 and DT (p<0.001 vs. both) vaccines. 6/3,085 and 2/3,085 peptides were exclusively recognized in (10/10) sera from children with whooping cough and DTPa2 vaccination, respectively. DTPwc resembles more closely the whooping cough reactome as compared to acellular vaccines. We could identify a unique recognition signature common for each vaccination group (10/10 children). Peptide microarray technology allows detection of subtle differences in

  6. A cyclic peptidic serine protease inhibitor

    DEFF Research Database (Denmark)

    Zhao, Baoyu; Xu, Peng; Jiang, Longguang

    2014-01-01

    Peptides are attracting increasing interest as protease inhibitors. Here, we demonstrate a new inhibitory mechanism and a new type of exosite interactions for a phage-displayed peptide library-derived competitive inhibitor, mupain-1 (CPAYSRYLDC), of the serine protease murine urokinase...... pocket, its carbonyl group aligning improperly relative to Ser195 and the oxyanion hole, explaining why the peptide is an inhibitor rather than a substrate. Substitution of the P1 Arg with novel unnatural Arg analogues with aliphatic or aromatic ring structures led to an increased affinity, depending......, in spite of a less favorable binding entropy and loss of a polar interaction. We conclude that increased flexibility of the peptide allows more favorable exosite interactions, which, in combination with the use of novel Arg analogues as P1 residues, can be used to manipulate the affinity and specificity...

  7. Natural analogue working group

    International Nuclear Information System (INIS)

    Come, B.; Chapman, N.

    1986-01-01

    A Natural Analogue Working Group was established by the Commission of the European Communities in 1985. The purpose of this group is to bring together modellers with earth scientists and others, so that maximum benefit can be obtained from natural analogue studies with a view to safe geological disposal of radioactive waste. The first meeting of this group was held in Brussels from November 5 to 7, 1985. The discussions mainly concerned the identification of the modellers' needs and of the earth scientists' capacity to provide for them. Following the debates, a written statement was produced by the Group; this document forms the core of the present Report. Notes and outlines of many of the presentations made are grouped in four appendixes. The valuable contribution of all those involved in the meeting is gratefully acknowledged

  8. An optimized method for measuring hypocretin-1 peptide in the mouse brain reveals differential circadian regulation of hypocretin-1 levels rostral and caudal to the hypothalamus.

    Science.gov (United States)

    Justinussen, J L; Holm, A; Kornum, B R

    2015-12-03

    The hypocretin/orexin system regulates, among other things, sleep and energy homeostasis. The system is likely regulated by both homeostatic and circadian mechanisms. Little is known about local differences in the regulation of hypocretin activity. The aim of this study was to establish an optimized peptide quantification method for hypocretin-1 extracted from different mouse brain areas and use this method for investigating circadian fluctuations of hypocretin-1 levels in these areas. The results show that hypocretin-1 peptide can be extracted from small pieces of intact tissue, with sufficient yield for measurements in a standard radioimmunoassay. Utilizing the optimized method, it was found that prepro-hypocretin mRNA and peptide show circadian fluctuations in the mouse brain. This study further demonstrates that the hypocretin-1 peptide level in the frontal brain peaks during dark as does prepro-hypocretin mRNA in the hypothalamus. However, in midbrain and brainstem tissue caudal to the hypothalamus, there was less circadian fluctuation and a tendency for higher levels during the light phase. These data suggest that regulation of the hypocretin system differs between brain areas. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

    Ciudad, M Teresa; Sorvillo, Nicoletta; van Alphen, Floris P.J.; Catalán, Diego; Meijer, Sander; Voorberg, Jan; Jaraquemada, Dolores

    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

  10. Comprehensive peptidomic and glycomic evaluation reveals that sweet whey permeate from colostrum is a source of milk protein-derived peptides and oligosaccharides

    NARCIS (Netherlands)

    Dallas, D.C.; Weinborn, V.; Moura Bell, de J.M.L.N.; Wang, M.; Parker, E.A.; Guerrero, A.; Hettinga, K.A.; Lebrilla, C.B.; German, J.B.; Barile, D.

    2014-01-01

    Whey permeate is a co-product obtained when cheese whey is passed through an ultrafiltration membrane to concentrate whey proteins. Whey proteins are retained by the membrane, whereas the low-molecular weight compounds such as lactose, salts, oligosaccharides and peptides pass through the membrane

  11. Screening of random peptide library of hemagglutinin from pandemic 2009 A(H1N1 influenza virus reveals unexpected antigenically important regions.

    Directory of Open Access Journals (Sweden)

    Wanghui Xu

    Full Text Available The antigenic structure of the membrane protein hemagglutinin (HA from the 2009 A(H1N1 influenza virus was dissected with a high-throughput screening method using complex antisera. The approach involves generating yeast cell libraries displaying a pool of random peptides of controllable lengths on the cell surface, followed by one round of fluorescence-activated cell sorting (FACS against antisera from mouse, goat and human, respectively. The amino acid residue frequency appearing in the antigenic peptides at both the primary sequence and structural level was determined and used to identify "hot spots" or antigenically important regions. Unexpectedly, different antigenic structures were seen for different antisera. Moreover, five antigenic regions were identified, of which all but one are located in the conserved HA stem region that is responsible for membrane fusion. Our findings are corroborated by several recent studies on cross-neutralizing H1 subtype antibodies that recognize the HA stem region. The antigenic peptides identified may provide clues for creating peptide vaccines with better accessibility to memory B cells and better induction of cross-neutralizing antibodies than the whole HA protein. The scheme used in this study enables a direct mapping of the antigenic regions of viral proteins recognized by antisera, and may be useful for dissecting the antigenic structures of other viral proteins.

  12. Aspartame and Its Analogues

    Science.gov (United States)

    Pavlova, L. A.; Komarova, T. V.; Davidovich, Yurii A.; Rogozhin, S. V.

    1981-04-01

    The results of studies on the biochemistry of the sweet taste are briefly reviewed. The methods of synthesis of "aspartame" — a sweet dipeptide — are considered, its structural analogues are described, and quantitative estimates are made of the degree of sweetness relative to sucrose. Attention is concentrated mainly on problems of the relation between the structure of the substance and its taste in the series of aspartyl derivatives. The bibliography includes 118 references.

  13. The Palmottu analogue project

    International Nuclear Information System (INIS)

    Ahonen, L.; Blomqvist, R.; Suksi, J.

    1993-01-01

    The report gives a summary of the results of investigations carried out in 1992 at the Palmottu natural analogue study site, which is a small U-Th mineralization in Nummi-Pusula, southwestern Finland. Additionally, the report includes several separate articles dealing with various aspects of the Palmottu Analogue Project: (1) deep groundwater flow, (2) interpretation of hydraulic connections, (3) characterization of groundwater colloids, (4) uranium mineral-groundwater equilibrium, (5) water-rock interaction and (6) modelling of in situ matrix diffusion. The Palmottu Analogue Project aims at a more profound understanding of radionuclide transport processes in fractured crystalline bedrock. The essential factors controlling transport are groundwater flow and interaction between water and rock. Accordingly, the study includes (1) structural interpretations partly based on geophysical measurements, (2) hydrological studies including hydraulic drill-hole measurements, (3) flow modelling, (4) hydrogeochemical characterization of groundwater, uranium chemistry and colloid chemistry, (5) mineralogical studies, (6) geochemical interpretation and modelling, (7) studies of radionuclide mobilization and retardation including matrix diffusion, and (8) modelling of uranium series data. Palaeohydrogeological aspects, due to the anticipated future glaciation of the Fennoscandian Shield, are of special interest. Quaternary sediments are studied to gain information on post-glacial migration in the overburden. (orig.)

  14. Quantum analogue computing.

    Science.gov (United States)

    Kendon, Vivien M; Nemoto, Kae; Munro, William J

    2010-08-13

    We briefly review what a quantum computer is, what it promises to do for us and why it is so hard to build one. Among the first applications anticipated to bear fruit is the quantum simulation of quantum systems. While most quantum computation is an extension of classical digital computation, quantum simulation differs fundamentally in how the data are encoded in the quantum computer. To perform a quantum simulation, the Hilbert space of the system to be simulated is mapped directly onto the Hilbert space of the (logical) qubits in the quantum computer. This type of direct correspondence is how data are encoded in a classical analogue computer. There is no binary encoding, and increasing precision becomes exponentially costly: an extra bit of precision doubles the size of the computer. This has important consequences for both the precision and error-correction requirements of quantum simulation, and significant open questions remain about its practicality. It also means that the quantum version of analogue computers, continuous-variable quantum computers, becomes an equally efficient architecture for quantum simulation. Lessons from past use of classical analogue computers can help us to build better quantum simulators in future.

  15. In silico peptide-binding predictions of passerine MHC class I reveal similarities across distantly related species, suggesting convergence on the level of protein function.

    Science.gov (United States)

    Follin, Elna; Karlsson, Maria; Lundegaard, Claus; Nielsen, Morten; Wallin, Stefan; Paulsson, Kajsa; Westerdahl, Helena

    2013-04-01

    The major histocompatibility complex (MHC) genes are the most polymorphic genes found in the vertebrate genome, and they encode proteins that play an essential role in the adaptive immune response. Many songbirds (passerines) have been shown to have a large number of transcribed MHC class I genes compared to most mammals. To elucidate the reason for this large number of genes, we compared 14 MHC class I alleles (α1-α3 domains), from great reed warbler, house sparrow and tree sparrow, via phylogenetic analysis, homology modelling and in silico peptide-binding predictions to investigate their functional and genetic relationships. We found more pronounced clustering of the MHC class I allomorphs (allele specific proteins) in regards to their function (peptide-binding specificities) compared to their genetic relationships (amino acid sequences), indicating that the high number of alleles is of functional significance. The MHC class I allomorphs from house sparrow and tree sparrow, species that diverged 10 million years ago (MYA), had overlapping peptide-binding specificities, and these similarities across species were also confirmed in phylogenetic analyses based on amino acid sequences. Notably, there were also overlapping peptide-binding specificities in the allomorphs from house sparrow and great reed warbler, although these species diverged 30 MYA. This overlap was not found in a tree based on amino acid sequences. Our interpretation is that convergent evolution on the level of the protein function, possibly driven by selection from shared pathogens, has resulted in allomorphs with similar peptide-binding repertoires, although trans-species evolution in combination with gene conversion cannot be ruled out.

  16. Peptide dendrimers

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2005-01-01

    Roč. 11, - (2005), 757-788 ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005

  17. An optimized method for measuring hypocretin-1 peptide in the mouse brain reveals differential circadian regulation of hypocretin-1 levels rostral and caudal to the hypothalamus

    DEFF Research Database (Denmark)

    Justinussen, J L; Holm, A; Kornum, B R

    2015-01-01

    an optimized peptide quantification method for hypocretin-1 extracted from different mouse brain areas and use this method for investigating circadian fluctuations of hypocretin-1 levels in these areas. The results show that hypocretin-1 peptide can be extracted from small pieces of intact tissue...... as does prepro-hypocretin mRNA in the hypothalamus. However, in midbrain and brainstem tissue caudal to the hypothalamus, there was less circadian fluctuation and a tendency for higher levels during the light phase. These data suggest that regulation of the hypocretin system differs between brain areas.......The hypocretin/orexin system regulates, among other things, sleep and energy homeostasis. The system is likely regulated by both homeostatic and circadian mechanisms. Little is known about local differences in the regulation of hypocretin activity. The aim of this study was to establish...

  18. Catalytic water co-existing with a product peptide in the active site of HIV-1 protease revealed by X-ray structure analysis.

    Directory of Open Access Journals (Sweden)

    Vishal Prashar

    Full Text Available BACKGROUND: It is known that HIV-1 protease is an important target for design of antiviral compounds in the treatment of Acquired Immuno Deficiency Syndrome (AIDS. In this context, understanding the catalytic mechanism of the enzyme is of crucial importance as transition state structure directs inhibitor design. Most mechanistic proposals invoke nucleophilic attack on the scissile peptide bond by a water molecule. But such a water molecule coexisting with any ligand in the active site has not been found so far in the crystal structures. PRINCIPAL FINDINGS: We report here the first observation of the coexistence in the active site, of a water molecule WAT1, along with the carboxyl terminal product (Q product peptide. The product peptide has been generated in situ through cleavage of the full-length substrate. The N-terminal product (P product has diffused out and is replaced by a set of water molecules while the Q product is still held in the active site through hydrogen bonds. The position of WAT1, which hydrogen bonds to both the catalytic aspartates, is different from when there is no substrate bound in the active site. We propose WAT1 to be the position from where catalytic water attacks the scissile peptide bond. Comparison of structures of HIV-1 protease complexed with the same oligopeptide substrate, but at pH 2.0 and at pH 7.0 shows interesting changes in the conformation and hydrogen bonding interactions from the catalytic aspartates. CONCLUSIONS/SIGNIFICANCE: The structure is suggestive of the repositioning, during substrate binding, of the catalytic water for activation and subsequent nucleophilic attack. The structure could be a snap shot of the enzyme active site primed for the next round of catalysis. This structure further suggests that to achieve the goal of designing inhibitors mimicking the transition-state, the hydrogen-bonding pattern between WAT1 and the enzyme should be replicated.

  19. Catalytic water co-existing with a product peptide in the active site of HIV-1 protease revealed by X-ray structure analysis.

    Science.gov (United States)

    Prashar, Vishal; Bihani, Subhash; Das, Amit; Ferrer, Jean-Luc; Hosur, Madhusoodan

    2009-11-17

    It is known that HIV-1 protease is an important target for design of antiviral compounds in the treatment of Acquired Immuno Deficiency Syndrome (AIDS). In this context, understanding the catalytic mechanism of the enzyme is of crucial importance as transition state structure directs inhibitor design. Most mechanistic proposals invoke nucleophilic attack on the scissile peptide bond by a water molecule. But such a water molecule coexisting with any ligand in the active site has not been found so far in the crystal structures. We report here the first observation of the coexistence in the active site, of a water molecule WAT1, along with the carboxyl terminal product (Q product) peptide. The product peptide has been generated in situ through cleavage of the full-length substrate. The N-terminal product (P product) has diffused out and is replaced by a set of water molecules while the Q product is still held in the active site through hydrogen bonds. The position of WAT1, which hydrogen bonds to both the catalytic aspartates, is different from when there is no substrate bound in the active site. We propose WAT1 to be the position from where catalytic water attacks the scissile peptide bond. Comparison of structures of HIV-1 protease complexed with the same oligopeptide substrate, but at pH 2.0 and at pH 7.0 shows interesting changes in the conformation and hydrogen bonding interactions from the catalytic aspartates. The structure is suggestive of the repositioning, during substrate binding, of the catalytic water for activation and subsequent nucleophilic attack. The structure could be a snap shot of the enzyme active site primed for the next round of catalysis. This structure further suggests that to achieve the goal of designing inhibitors mimicking the transition-state, the hydrogen-bonding pattern between WAT1 and the enzyme should be replicated.

  20. Lead optimization of antimalarial propafenone analogues.

    Science.gov (United States)

    Lowes, David; Pradhan, Anupam; Iyer, Lalitha V; Parman, Toufan; Gow, Jason; Zhu, Fangyi; Furimsky, Anna; Lemoff, Andrew; Guiguemde, W Armand; Sigal, Martina; Clark, Julie A; Wilson, Emily; Tang, Liang; Connelly, Michele C; Derisi, Joseph L; Kyle, Dennis E; Mirsalis, Jon; Guy, R Kiplin

    2012-07-12

    Previously reported studies identified analogues of propafenone that had potent antimalarial activity, reduced cardiac ion channel activity, and properties that suggested the potential for clinical development for malaria. Careful examination of the bioavailability, pharmacokinetics, toxicology, and efficacy of this series of compounds using rodent models revealed orally bioavailable compounds that are nontoxic and suppress parasitemia in vivo. Although these compounds possess potential for further preclinical development, they also carry some significant challenges.

  1. A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

    Directory of Open Access Journals (Sweden)

    Arno Verlee

    2017-02-01

    Full Text Available For the synthesis of m-sulfamoylbenzamide analogues, small molecules which are known for their bioactivity, a chemoselective procedure has been developed starting from m-(chlorosulfonylbenzoyl chloride. Although a chemoselective process in batch was already reported, a continuous-flow process reveals an increased selectivity at higher temperatures and without catalysts. In total, 15 analogues were synthesized, using similar conditions, with yields ranging between 65 and 99%. This is the first automated and chemoselective synthesis of m-sulfamoylbenzamide analogues.

  2. Neoglycolipids for Prolonging the Effects of Peptides

    DEFF Research Database (Denmark)

    van Witteloostuijn, Søren Blok; Mannerstedt, Karin Margareta Sophia; Wismann, Pernille

    2017-01-01

    Novel principles for optimizing the properties of peptide-based drugs are needed in order to leverage their full pharmacological potential. We present the design, synthesis, and evaluation of a library of neoglycolipidated glucagon-like peptide 1 (GLP-1) analogues, which are valuable drug...... was maintained or even improved compared to native GLP-1. This translated into pronounced in vivo efficacy in terms of both decreased acute food intake and improved glucose homeostasis in mice. Thus, we propose neoglycolipidation as a novel, general method for modulating the properties of therapeutic peptides...

  3. Long-acting lipidated analogue of human pancreatic polypeptide is slowly released into circulation

    DEFF Research Database (Denmark)

    Bellmann-Sickert, Kathrin; Elling, Christian E; Madsen, Andreas N

    2011-01-01

    The main disadvantages of peptide pharmaceuticals are their rapid degradation and excretion, their low hydrophilicity, and low shelf lifes. These bottlenecks can be circumvented by acylation with fatty acids (lipidation) or polyethylene glycol (PEGylation). Here, we describe the modification....... Lipidation resulted in prolonged action of the hPP analogue in respect of reducing food intake in mice after subcutaneous administration. Therefore, the lipidated hPP analogue could constitute a potential new therapeutic agent against obesity....

  4. IMAC fractionation in combination with LC-MS reveals H2B and NIF-1 peptides as potential bladder cancer biomarkers.

    Science.gov (United States)

    Frantzi, Maria; Zoidakis, Jerome; Papadopoulos, Theofilos; Zürbig, Petra; Katafigiotis, Ioannis; Stravodimos, Konstantinos; Lazaris, Andreas; Giannopoulou, Ioanna; Ploumidis, Achilles; Mischak, Harald; Mullen, William; Vlahou, Antonia

    2013-09-06

    Improvement in bladder cancer (BC) management requires more effective diagnosis and prognosis of disease recurrence and progression. Urinary biomarkers attract special interest because of the noninvasive means of urine collection. Proteomic analysis of urine entails the adoption of a fractionation methodology to reduce sample complexity. In this study, we applied immobilized metal affinity chromatography in combination with high-resolution LC-MS/MS for the discovery of native urinary peptides potentially associated with BC aggressiveness. This approach was employed toward urine samples from patients with invasive BC, noninvasive BC, and benign urogenital diseases. A total of 1845 peptides were identified, corresponding to a total of 638 precursor proteins. Specific enrichment for proteins involved in nucleosome assembly and for zinc-finger transcription factors was observed. The differential expression of two candidate biomarkers, histone H2B and NIF-1 (zinc finger 335) in BC, was verified in independent sets of urine samples by ELISA and by immunohistochemical analysis of BC tissue. The results collectively support changes in the expression of both of these proteins with tumor progression, suggesting their potential role as markers for discriminating BC stages. In addition, the data indicate a possible involvement of NIF-1 in BC progression, likely as a suppressor and through interactions with Sox9 and HoxA1.

  5. In-Culture Cross-Linking of Bacterial Cells Reveals Large-Scale Dynamic Protein-Protein Interactions at the Peptide Level.

    Science.gov (United States)

    de Jong, Luitzen; de Koning, Edward A; Roseboom, Winfried; Buncherd, Hansuk; Wanner, Martin J; Dapic, Irena; Jansen, Petra J; van Maarseveen, Jan H; Corthals, Garry L; Lewis, Peter J; Hamoen, Leendert W; de Koster, Chris G

    2017-07-07

    Identification of dynamic protein-protein interactions at the peptide level on a proteomic scale is a challenging approach that is still in its infancy. We have developed a system to cross-link cells directly in culture with the special lysine cross-linker bis(succinimidyl)-3-azidomethyl-glutarate (BAMG). We used the Gram-positive model bacterium Bacillus subtilis as an exemplar system. Within 5 min extensive intracellular cross-linking was detected, while intracellular cross-linking in a Gram-negative species, Escherichia coli, was still undetectable after 30 min, in agreement with the low permeability in this organism for lipophilic compounds like BAMG. We were able to identify 82 unique interprotein cross-linked peptides with cross-links occur in assemblies involved in transcription and translation. Several of these interactions are new, and we identified a binding site between the δ and β' subunit of RNA polymerase close to the downstream DNA channel, providing a clue into how δ might regulate promoter selectivity and promote RNA polymerase recycling. Our methodology opens new avenues to investigate the functional dynamic organization of complex protein assemblies involved in bacterial growth. Data are available via ProteomeXchange with identifier PXD006287.

  6. Alligator Rivers analogue project

    International Nuclear Information System (INIS)

    Duerden, P.

    1990-01-01

    Australian Nuclear Science and Technology Organization has extensively evaluated uranium ore bodies in the Alligator Rivers Uranium Province in Australia as analogues of radioactive waste repositories. The work was extended for a three-year program as an international project based on the Koongarra uranium deposit and sponsored by the OECD Nuclear Energy Agency. The technical program comprises six major sub-projects involving modelling and experimental work: modelling of radionuclide migration; hydrogeology of the Koongarra uranium deposit; uranium/thorium series disequilibria studies; groundwater and colloid studies; fission product studies; transuranic nuclide studies; an outline of the technical programs and a summary of progress in the technical sub-projects is given. This is followed by a series of technical reports which briefly describe current research tasks, and which have been separately indexed

  7. New analogues of Cucurbita maxima trypsin inhibitor III (CMTI III) with simplified structure.

    Science.gov (United States)

    Rolka, K; Kupryszewski, G; Rózycki, J; Ragnarsson, U; Zbyryt, T; Otlewski, J

    1992-10-01

    Seven new analogues of trypsin inhibitor CMTI III were obtained by solid-phase peptide synthesis. Three analogues contained only two, instead of three, disulfide bridges, whereas the molecules of the next four analogues were shortened at the N- and/or C-terminus. The elimination of one disulfide bridge in CMTI III induces a decrease in the association equilibrium constants by 6-7 orders of magnitude, whereas the removal of one, two or three amino-acid residues at the N- and/or C-terminus does not significantly affect the activity.

  8. A Short Term Analogue Memory

    DEFF Research Database (Denmark)

    Shah, Peter Jivan

    1992-01-01

    A short term analogue memory is described. It is based on a well-known sample-hold topology in which leakage currents have been minimized partly by circuit design and partly by layout techniques. Measurements on a test chip implemented in a standard 2.4 micron analogue CMOS process show a droop...

  9. Iodination and stability of somatostatin analogues: comparison of iodination techniques. A practical overview.

    Science.gov (United States)

    de Blois, Erik; Chan, Ho Sze; Breeman, Wouter A P

    2012-01-01

    For iodination ((125/127)I) of tyrosine-containing peptides, chloramin-T, Pre-Coated Iodo-Gen(®) tubes and Iodo-Beads(®) (Pierce) are commonly used for in vitro radioligand investigations and there have been reliant vendors hereof for decades. However, commercial availability of these radio-iodinated peptides is decreasing. For continuation of our research in this field we investigated and optimized (radio-)iodination of somatostatin analogues. In literature, radioiodination using here described somatostatin analogues and iodination techniques are described separately. Here we present an overview, including High Performance Liquid Chromatography (HPLC) separation and characterisation by mass spectrometry, to obtain mono- and di-iodinated analogues. Reaction kinetics of (125/127)I iodinated somatostatin analogues were investigated as function of reaction time and concentration of reactants, including somatostatin analogues, iodine and oxidizing agent. To our knowledge, for the here described somatostatin analogues, no (127)I iodination and optimization are described. (Radio-)iodinated somatostatin analogues could be preserved with a >90% radiochemical purity for 1 month after reversed phase HPLC-purification.

  10. Analogues of luteinizing hormone-releasing hormone containing cytotoxic groups.

    Science.gov (United States)

    Janáky, T; Juhász, A; Bajusz, S; Csernus, V; Srkalovic, G; Bokser, L; Milovanovic, S; Redding, T W; Rékási, Z; Nagy, A

    1992-02-01

    In an attempt to produce better cytotoxic analogues, chemotherapeutic antineoplastic radicals including an alkylating nitrogen mustard derivative of D-phenylalanine (D-melphalan), reactive cyclopropane, anthraquinone derivatives [2-(hydroxymethyl)anthraquinone and the anticancer antibiotic doxorubicin], and an antimetabolite (methotrexate) were coupled to suitably modified agonists and antagonists of luteinizing hormone-releasing hormone (LH-RH). Analogues with D-lysine6 and D-ornithine6 or N epsilon-(2,3-diaminopropionyl)-D-lysine and N delta-(2,3-diaminopropionyl)-D-ornithine were used as carriers for one or two cytotoxic moieties. The enhanced biological activities produced by the incorporation of D amino acids into position 6 of the agonistic analogues were further increased by the attachment of hydrophobic cytotoxic groups, resulting in compounds with 10-50 times higher activity than LH-RH. Most of the monosubstituted agonistic analogues showed high affinities for the membrane receptors of human breast cancer cells, while the receptor binding affinities of peptides containing two cytotoxic side chains were lower. Antagonistic carriers [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Trp3,Arg5,D-Lys6,D-Ala10] LH-RH [where Nal(2) is 3-(2-naphthyl)alanine], [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Trp3,Arg5,N epsilon-(2,3-diaminopropionyl)-D-Lys6,D-Ala10]LH-RH, and their D-Pal(3)3 homologs [Pal(3) is 3-(3-pyridyl)alanine] as well as [Ac-D-Nal(2)1,D-Phe(4Cl)2,D-Pal(3)3,Tyr5,N epsilon-(2,3-diamino-propionyl)-D-Lys6,D-Ala10]LH-RH were linked to cytotoxic compounds. The hybrid molecules inhibited ovulation in rats at doses of 10 micrograms and suppressed LH release in vitro. The receptor binding of cytotoxic analogues was decreased compared to the precursor peptides, although analogues with 2-(hydroxymethyl)anthraquinone hemiglutarate had high affinities. All of the cytotoxic analogues tested inhibited [3H]thymidine incorporation into DNA in cultures of human breast and prostate cancer cell lines

  11. Localisation and mechanism of renal retention of radiolabelled somatostatin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Melis, Marleen; Krenning, Eric P.; Bernard, Bert F.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Barone, Raffaella [UCL, Centre of Nuclear Medicine and Laboratory of PET, Brussels (Belgium); Visser, Theo J. [Erasmus MC, Department of Internal Medicine, Rotterdam (Netherlands)

    2005-10-01

    Radiolabelled somatostatin analogues, such as octreotide and octreotate, are used for tumour scintigraphy and radionuclide therapy. The kidney is the most important critical organ during such therapy owing to the reabsorption and retention of radiolabelled peptides. The aim of this study was to investigate in a rat model both the localisation and the mechanism of renal uptake after intravenous injection of radiolabelled somatostatin analogues. The multi-ligand megalin/cubilin receptor complex, responsible for reabsorption of many peptides and proteins in the kidney, is an interesting candidate for renal endocytosis of these peptide analogues. For localisation studies, ex vivo autoradiography and micro-autoradiography of rat kidneys were performed 1-24 h after injection of radiolabelled somatostatin analogues and compared with the renal anti-megalin immunohistochemical staining pattern. To confirm a role of megalin in the mechanism of renal retention of [{sup 111}In-DTPA]octreotide, the effects of three inhibitory substances were explored in rats. Renal ex vivo autoradiography showed high cortical radioactivity and lower radioactivity in the outer medulla. The distribution of cortical radioactivity was inhomogeneous. Micro-autoradiography indicated that radioactivity was only retained in the proximal tubules. The anti-megalin immunohistochemical staining pattern showed a strong similarity with the renal [{sup 111}In-DTPA]octreotide ex vivo autoradiograms. Biodistribution studies showed that co-injection of positively charged d-lysine reduced renal uptake to 60% of control. Sodium maleate reduced renal [{sup 111}In-DTPA]octreotide uptake to 15% of control. Finally, cisplatin pre-treatment of rats reduced kidney uptake to 70% of control. Renal retention of [{sup 111}In-DTPA]octreotide is confined to proximal tubules in the rat kidney, in which megalin-mediated endocytosis may play an important part. (orig.)

  12. Inhibition of Plant-Pathogenic Bacteria by Short Synthetic Cecropin A-Melittin Hybrid Peptides

    OpenAIRE

    Ferre, Rafael; Badosa, Esther; Feliu, Lidia; Planas, Marta; Montesinos, Emili; Bardají, Eduard

    2006-01-01

    Short peptides of 11 residues were synthesized and tested against the economically important plant pathogenic bacteria Erwinia amylovora, Pseudomonas syringae, and Xanthomonas vesicatoria and compared to the previously described peptide Pep3 (WKLFKKILKVL-NH2). The antimicrobial activity of Pep3 and 22 analogues was evaluated in terms of the MIC and the 50% effective dose (ED50) for growth. Peptide cytotoxicity against human red blood cells and peptide stability toward protease degradation wer...

  13. Development of 99mTc labelled somatostatin analogues with high affinity for somatostatin receptors

    International Nuclear Information System (INIS)

    Maina, T.; Nock, B.; Nicolopoulou, A.; Tsipra, C.; Poppe, M.; Chiotellis, E.

    2001-01-01

    A recent development in oncology involves the use of metabolically stabilized peptide hormone analogues labelled with metallic radionuclides for the diagnosis or therapy of malignant disease. This approach was successfully applied for the first time in the visualization of somatostatin positive tumours and their metastases with 111 In DTPA-octreotide. In an effort to obtain a 99m Tc somatostatin receptor affine radioligand we describe herein the synthesis, radiochemistry and preliminary biological evaluation of two novel 99m Tc labelled somatostatin analogues, N 4 -TOC and N 4 -RC-160. In these compounds a tetraamine bifunctional unit was covalently attached to the N-terminal (D)Phe 1 of the peptide chain using Boc-protection strategies. The peptide conjugates were purified by high performance liquid chromatography (HPLC) and characterized by UV/Vis and ES-MS spectroscopies. As revealed by HPLC, 99m Tc labelling was quantitative under mild conditions, leading to a single 99m Tc species in high specific activities. Affinity of 99m Tc N 4 -TOC for the somatostatin receptor, as determined by in vitro binding assays in rat brain cortex membranes, was found unaffected by the presence of the bulky metal chelate. The binding properties of 99m Tc N 4 -RC-160 could not be determined by this assay due to an extremely high non-specific binding of this radioligand, and will be shortly investigated by other methods. Tissue distribution in healthy mice revealed that 99m Tc N 4 -TOC is clearing mainly through the kidneys and the urinary tract whereas 99m Tc N 4 -RC-160 shows a high accumulation in the liver as a result of its lipophilicity. Analysis of urine samples by HPLC showed that 99m Tc N 4 -TOC is excreted integer from the body of mice, while 99m Tc N 4 -RC-160 is totally transformed to an unidentified hydrophilic metabolite in vivo. The location of this metabolism is currently investigated. In vivo blocking experiments using animals pre-treated with 50 μg octreotide

  14. Elucidation of the Signal Transduction Pathways Activated by the Plant Natriuretic Peptide AtPNP-A

    KAUST Repository

    Turek, Ilona

    2014-01-01

    Plant natriuretic peptides (PNPs) comprise a novel class of hormones that share some sequence similarity in the active site with their animal analogues that function as regulators of salt and water balance. A PNP present in Arabidopsis thaliana (At

  15. Chemopreventive properties of curcumin analogues ...

    African Journals Online (AJOL)

    Chemopreventive properties of curcumin analogues, ... These compounds .... using microscope with 400 × magnification. APC ... Figure 3: Microscopic images of rat colorectal tissue stained with APC rabbit polyclonal antibody with different.

  16. Bioluminescence of beetle luciferases with 6'-amino-D-luciferin analogues reveals excited keto-oxyluciferin as the emitter and phenolate/luciferin binding site interactions modulate bioluminescence colors.

    Science.gov (United States)

    Viviani, Vadim R; Neves, Deimison Rodrigues; Amaral, Danilo Trabuco; Prado, Rogilene A; Matsuhashi, Takuto; Hirano, Takashi

    2014-08-19

    Beetle luciferases produce different bioluminescence colors from green to red using the same d-luciferin substrate. Despite many studies of the mechanisms and structural determinants of bioluminescence colors with firefly luciferases, the identity of the emitters and the specific active site interactions responsible for bioluminescence color modulation remain elusive. To address these questions, we analyzed the bioluminescence spectra with 6'-amino-D-luciferin (aminoluciferin) and its 5,5-dimethyl analogue using a set of recombinant beetle luciferases that naturally elicit different colors and different pH sensitivities (pH-sensitive, Amydetes vivianii λmax=538 nm, Macrolampis sp2 λmax=564 nm; pH-insensitive, Phrixotrix hirtus λmax=623 nm, Phrixotrix vivianii λmax=546 nm, and Pyrearinus termitilluminans λmax=534 nm), a luciferase-like enzyme (Tenebrionidae, Zophobas morio λmax=613 nm), and mutants of C311 (S314). The green-yellow-emitting luciferases display red-shifted bioluminescence spectra with aminoluciferin in relation to those with D-luciferin, whereas the red-emitting luciferases displayed blue-shifted spectra. Bioluminescence spectra with 5,5-dimethylaminoluciferin, in which enolization is blocked, were almost identical to those of aminoluciferin. Fluorescence probing using 2-(4-toluidino)naphthalene-6-sulfonate and inference with aminoluciferin confirm that the luciferin binding site of the red-shifted luciferases is more polar than in the case of the green-yellow-emitting luciferases. Altogether, the results show that the keto form of excited oxyluciferin is the emitter in beetle bioluminescence and that bioluminescence colors are essentially modulated by interactions of the 6'-hydroxy group of oxyluciferin and basic moieties under the influence of the microenvironment polarity of the active site: a strong interaction between a base moiety and oxyluciferin phenol in a hydrophobic microenvironment promotes green-yellow emission, whereas a more polar

  17. Cholera toxin subunit B peptide fusion proteins reveal impaired oral tolerance induction in diabetes-prone but not in diabetes-resistant mice.

    Science.gov (United States)

    Presa, Maximiliano; Ortiz, Angela Zarama; Garabatos, Nahir; Izquierdo, Cristina; Rivas, Elisa I; Teyton, Luc; Mora, Conchi; Serreze, David; Stratmann, Thomas

    2013-11-01

    The cholera toxin B subunit (CTB) has been used as adjuvant to improve oral vaccine delivery in type 1 diabetes. The effect of CTB/peptide formulations on Ag-specific CD4(+) T cells has remained largely unexplored. Here, using tetramer analysis, we investigated how oral delivery of CTB fused to two CD4(+) T-cell epitopes, the BDC-2.5 T-cell 2.5 mi mimotope and glutamic acid decarboxylase (GAD) 286-300, affected diabetogenic CD4(+) T cells in nonobese diabetic (NOD) mice. When administered i.p., CTB-2.5 mi activated 2.5 mi(+) T cells and following intragastric delivery generated Ag-specific Foxp3(+) Treg and Th2 cells. While 2.5 mi(+) and GAD-specific T cells were tolerized in diabetes-resistant NODxB6.Foxp3(EGFP) F1 and nonobese resistant (NOR) mice, this did not occur in NOD mice. This indicated that NOD mice had a recessive genetic resistance to induce oral tolerance to both CTB-fused epitopes. In contrast to NODxB6.Foxp3(EGFP) F1 mice, oral treatment in NOD mice lead to strong 2.5 mi(+) T-cell activation and the sequestration of these cells to the effector-memory pool. Oral treatment of NOD mice with CTB-2.5 mi failed to prevent diabetes. These findings underline the importance of investigating the effect of oral vaccine formulations on diabetogenic T cells as in selected cases they may have counterproductive consequences in human patients. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. In vitro structure-activity relationship of Re-cyclized octreotide analogues

    Energy Technology Data Exchange (ETDEWEB)

    Dannoon, Shorouk F. [Department of Chemistry, University of Missouri, Columbia, MO 65211 (United States); Bigott-Hennkens, Heather M. [Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211 (United States); Ma Lixin [Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); International Institute of Nano and Molecular Medicine, University of Missouri, Columbia, MO 65211 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Gallazzi, Fabio [Structural Biology Core, University of Missouri, Columbia, MO 65211 (United States); Lewis, Michael R., E-mail: lewismic@missouri.ed [Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211 (United States); Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Jurisson, Silvia S., E-mail: jurissons@missouri.ed [Department of Chemistry, University of Missouri, Columbia, MO 65211 (United States); Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States)

    2010-07-15

    Introduction: Development of radiolabeled octreotide analogues is of interest for targeting somatostatin receptor (SSTR)-positive tumors for diagnostic and therapeutic purposes. We are investigating a direct labeling approach for incorporation of a Re ion into octreotide analogues, where the peptide sequences are cyclized via coordination to Re rather than through a disulfide bridge. Methods: Various octreotide analogue sequences and coordination systems (e.g., S{sub 2}N{sub 2} and S{sub 3}N) were synthesized and cyclized with nonradioactive Re. In vitro competitive binding assays with {sup 111}In-DOTA-Tyr{sup 3}-octreotide in AR42J rat pancreatic tumor cells yielded IC{sub 50} values as a measure of SSTR affinity of the Re-cyclized analogues. Three-dimensional structures of Re-cyclized Tyr{sup 3}-octreotate and its disulfide-bridged analogue were calculated from two-dimensional NMR experiments to visualize the effect of metal cyclization on the analogue's pharmacophore. Results: Only two of the 11 Re-cyclized analogues investigated showed moderate in vitro binding affinity toward somatostatin subtype 2 receptors. Three-dimensional molecular structures of Re- and disulfide-cyclized Tyr{sup 3}-octreotate were calculated, and both of their pharmacophore turns appear to be very similar with minor differences due to metal coordination to the amide nitrogen of one of the pharmacophore amino acids. Conclusions: Various Re-cyclized analogues were developed and analogue 4 had moderate affinity toward somatostatin subtype 2 receptors. In vitro stable studies that are in progress showed stable radiometal cyclization of octreotide analogues via NS{sub 3} and N{sub 2}S{sub 2} coordination forming five- and six-membered chelate rings. In vivo biodistribution studies are underway of {sup 99m}Tc-cyclized analogue 4.

  19. Studies of the antitumor mechanism of action of dermaseptin B2, a multifunctional cationic antimicrobial peptide, reveal a partial implication of cell surface glycosaminoglycans.

    Directory of Open Access Journals (Sweden)

    Célia Dos Santos

    Full Text Available Dermaseptin-B2 (DRS-B2 is a multifunctional cationic antimicrobial peptide (CAP isolated from frog skin secretion. We previously reported that DRS-B2 possesses anticancer and antiangiogenic activities in vitro and in vivo. In the present study, we evaluated the antiproliferative activity of DRS-B2 on numerous tumor cell lines, its cell internalization and studies of its molecular partners as well as their influences on its structure. Confocal microscopy using ([Alexa594]-(Cys0-DRS-B2 shows that in sensitive human tumor cells (PC3, DRS-B2 seems to accumulate rapidly at the cytoplasmic membranes and enters the cytoplasm and the nucleus, while in less sensitive tumor cells (U87MG, DRS-B2 is found packed in vesicles at the cell membrane. Furthermore FACS analysis shows that PC3 cells viability decreases after DRS-B2 treatment while U87 MG seems to be unaffected. However, "pull down" experiments performed with total protein pools from PC3 or U87MG cells and the comparison between the antiproliferative effect of DRS-B2 and its synthetic analog containing all D-amino acids suggest the absence of a stereo-selective protein receptor. Pretreatment of PC3 cells with sodium chlorate, decreases the antiproliferative activity of DRS-B2. This activity is partially restored after addition of exogenous chondroitin sulfate C (CS-C. Moreover, we demonstrate that at nanomolar concentrations CS-C potentiates the antiproliferative effect of DRS-B2. These results highlight the partial implication of glycosaminoglycans in the mechanism of antiproliferative action of DRS-B2. Structural analysis of DRS-B2 by circular dichroism in the presence of increasing concentration of CS-C shows that DRS-B2 adopts an α-helical structure. Finally, structure-activity-relationship studies suggest a key role of the W residue in position 3 of the DRS-B2 sequence for its antiproliferative activity.

  20. Highly potent metallopeptide analogues of luteinizing hormone-releasing hormone

    International Nuclear Information System (INIS)

    Bajusz, S.; Janaky, T.; Csernus, V.J.; Bokser, L.; Fekete, M.; Srkalovic, G.; Redding, T.W.; Schally, A.V.

    1989-01-01

    Metal complexes related to the cytotoxic complexes cisplatin [cis-diamminedichloroplatinum(II)] and transbis(salicylaldoximato)copper(II) were incorporated into suitably modified luteinizing hormone-releasing hormone (LH-RH) analogues containing D-lysine at position 6. Some of the metallopeptides thus obtained proved to be highly active LH-RH agonists or antagonists. Most metallopeptide analogues of LH-RH showed high affinities for the membrane receptors of rat pituitary and human breast cancer cells. Some of these metallopeptides had cytotoxic activity against human breast cancer and prostate cancer and prostate cancer cell lines in vitro. Such cytostatic metallopeptides could be envisioned as targeted chemotherapeutic agents in cancers that contain receptors for LH-RH-like peptides

  1. Somatostatin analogues labelled with 99mTc

    International Nuclear Information System (INIS)

    Obenaus, Esteban R.; Crudo, Jose L.; Edreira, Martin M.; Castiglia, Silvia G.

    1999-01-01

    Biological and radiochemical studies have been carried out on two labelled somatostatin analogues, the peptide RC-150 and the Tyr 3 -Octreotide. Both analogues have been labelled with 99m Tc using the direct and the indirect method and MAG-3 and HYNIC as chelating agents. By the direct method RC-150 was labelled using sodium ascorbate and dithionite as reducing agents. The radiochemical purity was 70%. By the indirect method, in the case of RC-160 with MAG-3 a radiochemical purity higher than 70% was attained while a purity of 100% was reached in the case of Tyr 3 -Octreotide with HYNIC. The biological distribution of HYNIC-Tyr 3 -Octreotide has been studied in rats. (author)

  2. Condensed matter analogues of cosmology

    Science.gov (United States)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    liveliest. A number of new experiments are reported here studying the dynamical evolution of domains and defects. Another phenomenon that played a key early role was the formation of vortices in the normal-to-superfluid transition in liquid helium-3. The complicated nature of the order parameter energy surface gives rise to a variety of intriguing effects. This too is still a vigorous field. Superconductivity is a special case because the symmetry that is broken is a gauge symmetry. This is also true in fundamental particle physics theories of relevance to cosmology, and for that reason experiments on superconductors are of particular interest to cosmologists. The situation in this case is more complicated because there are competing mechanisms of defect formation. Experiments in the field have not proved easy, either to perform or to interpret, but the papers in this collection show that good progress has been made of late. In recent years a new type of system has proved immensely fruitful, namely atomic Bose-Einstein or Fermi-gas condensates. Experiments on condensates with tunable parameters have in general provided broad support for the theory, and have also revealed a wide range of interesting and novel features, with intriguing possible analogues in cosmology (e.g. causal horizons and particle creation). The basic idea of the Kibble-Zurek mechanism has been shown to be relevant in this whole range of systems. But numerous complexities have also emerged, concerned for example with the role of inhomogeneity or the existence of composite defects. The field is still developing rapidly. Acknowledgments Finally, we would like to thank all the authors who have contributed to this issue, and the staff of Journal of Physics: Condensed Matter who have made it possible. Condensed matter analogues of cosmology contents Condensed matter analogues of cosmologyTom Kibble and Ajit Srivastava Symmetry breaking in nematic liquid crystals: analogy with cosmology and magnetismR Repnik, A

  3. Expanding the peptide beta-turn in alphagamma hybrid sequences: 12 atom hydrogen bonded helical and hairpin turns.

    Science.gov (United States)

    Chatterjee, Sunanda; Vasudev, Prema G; Raghothama, Srinivasarao; Ramakrishnan, Chandrasekharan; Shamala, Narayanaswamy; Balaram, Padmanabhan

    2009-04-29

    Hybrid peptide segments containing contiguous alpha and gamma amino acid residues can form C(12) hydrogen bonded turns which may be considered as backbone expanded analogues of C(10) (beta-turns) found in alphaalpha segments. Exploration of the regular hydrogen bonded conformations accessible for hybrid alphagamma sequences is facilitated by the use of a stereochemically constrained gamma amino acid residue gabapentin (1-aminomethylcyclohexaneacetic acid, Gpn), in which the two torsion angles about C(gamma)-C(beta) (theta(1)) and C(beta)-C(alpha) (theta(2)) are predominantly restricted to gauche conformations. The crystal structures of the octapeptides Boc-Gpn-Aib-Gpn-Aib-Gpn-Aib-Gpn-Aib-OMe (1) and Boc-Leu-Phe-Val-Aib-Gpn-Leu-Phe-Val-OMe (2) reveal two distinct conformations for the Aib-Gpn segment. Peptide 1 forms a continuous helix over the Aib(2)-Aib(6) segment, while the peptide 2 forms a beta-hairpin structure stabilized by four cross-strand hydrogen bonds with the Aib-Gpn segment forming a nonhelical C(12) turn. The robustness of the helix in peptide 1 in solution is demonstrated by NMR methods. Peptide 2 is conformationally fragile in solution with evidence of beta-hairpin conformations being obtained in methanol. Theoretical calculations permit delineation of the various C(12) hydrogen bonded structures which are energetically feasible in alphagamma and gammaalpha sequences.

  4. Peptide receptor radionuclide therapy of neuroendocrine tumours

    International Nuclear Information System (INIS)

    Bodei, L.; Giammarile, F.

    2009-01-01

    Neuroendocrine tumours are considered relatively rare tumours that have the characteristic property of secreting bioactive substances, such as amines and hormones. They constitute a heterogeneous group, characterized by good prognosis, but important disparities of the evolutionary potential. In the aggressive forms, the therapeutic strategies are limited. The metabolic or internal radiotherapy, using radiolabelled peptides, which can act at the same time on the primary tumour and its metastases, constitutes a tempting therapeutic alternative, currently in evolution. The prospects are related to the development of new radiopharmaceuticals, with the use of other peptide analogues whose applications will overflow the framework of the neuro-endocrine tumours. (authors)

  5. Peptides for radiotherapy of neuroendocrine cancers

    International Nuclear Information System (INIS)

    Melendez A, L.

    2002-01-01

    During the last decade there has been a resurgence of interest in therapeutic nuclear medicine, due to the limitation of conventional or external beam radiotherapy in the treatment of secondary or metastatic cancer sites outside of the primary treatment area. Some of the human tumours that produce metastases express high levels of somatostatin receptors. In order to make possible the diagnostic and radiotherapeutic treatment of these kind of tumours, various somatostatin analogue peptides have been developed in recent years. Peptides have become an important class of radiopharmaceuticals,due to its unique ability to detect specific sites as receptors or enzymes. This paper describes the work with 99m Tc to establish the labelling and analytical conditions for a somatostatin analogue as a precursor, to undertake a therapeutic radiopharmaceutical labelled with 188 Re for treatment of somatostatin receptor positive tumours. (Author)

  6. Labelling and evaluation of new stabilised neurotensin (8-13) analogues for SPET

    International Nuclear Information System (INIS)

    Chavatte, K.; Terriere, D.; Jeannin, L.

    1998-01-01

    Neurotensin (8-13) analogues were biologically stabilised by replacement of the peptide bond between amino acids 8 and 9 by the reduced ψ(CH 2 -NH) isostere. DTPA analogues for In-111 labelling and 2-bromo-phenyl-acetyl analogues for radioiodination, showed receptor affinities in the low nanomolar range in combination with a biological half live in human plasma up to 275 minutes. Biodistribution studies in male Wistar rats of metabolically stabilised and non-stabilised 111 In-DTPA-NT(8-13) analogues showed a major clearance from the blood through the kidneys. 125 I-labelled Neurotensin (8-13) analogues showed accumulation up to 2.2% of the injected dose per g tissue in the liver which might be an important disadvantage when diagnosis of tumours in the gut is aimed. It is strongly suggested that stabilised neurotensin (8-13) analogues whether labelled with In-111, I-123 and the near future with Tc-99m, may act as new potential peptidergic radiopharmaceuticals for SPET diagnosis of different NT-receptor positive tumours like non-endocrine pancreas carcinoma, small cell lung carcinoma or colon adeno carcinoma. It is enticing to speculate that metabolically stabilised Neurotensin (8-13) analogues labelled with an appropriate isotope might be useful in therapy of different human cancers. (author)

  7. Introduction to electronic analogue computers

    CERN Document Server

    Wass, C A A

    1965-01-01

    Introduction to Electronic Analogue Computers, Second Revised Edition is based on the ideas and experience of a group of workers at the Royal Aircraft Establishment, Farnborough, Hants. This edition is almost entirely the work of Mr. K. C. Garner, of the College of Aeronautics, Cranfield. As various advances have been made in the technology involving electronic analogue computers, this book presents discussions on the said progress, including some acquaintance with the capabilities of electronic circuits and equipment. This text also provides a mathematical background including simple differen

  8. Structural basis for the enhanced activity of cyclic antimicrobial peptides : The case of BPC194

    NARCIS (Netherlands)

    Mika, Jacek T.; Moiset, Gemma; Cirac, Anna D.; Feliu, Lidia; Bardaji, Eduard; Planas, Marta; Sengupta, Durba; Marrink, Siewert J.; Poolman, Bert

    We report the molecular basis for the differences in activity of cyclic and linear antimicrobial peptides. We iteratively performed atomistic molecular dynamics simulations and biophysical measurements to probe the interaction of a cyclic antimicrobial peptide and its inactive linear analogue with

  9. Superconductive analogue of spin glasses

    International Nuclear Information System (INIS)

    Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

    1987-07-01

    The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

  10. Causal structure of analogue spacetimes

    International Nuclear Information System (INIS)

    Barcelo, Carlos; Liberati, Stefano; Sonego, Sebastiano; Visser, Matt

    2004-01-01

    The so-called 'analogue models of general relativity' provide a number of specific physical systems, well outside the traditional realm of general relativity, that nevertheless are well-described by the differential geometry of curved spacetime. Specifically, the propagation of perturbations in these condensed matter systems is described by 'effective metrics' that carry with them notions of 'causal structure' as determined by an exchange of quasi-particles. These quasi-particle-induced causal structures serve as specific examples of what can be done in the presence of a Lorentzian metric without having recourse to the Einstein equations of general relativity. (After all, the underlying analogue model is governed by its own specific physics, not necessarily by the Einstein equations.) In this paper we take a careful look at what can be said about the causal structure of analogue spacetimes, focusing on those containing quasi-particle horizons, both with a view to seeing what is different from standard general relativity, and what the similarities might be. For definiteness, and because the physics is particularly simple to understand, we will phrase much of the discussion in terms of acoustic disturbances in moving fluids, where the underlying physics is ordinary fluid mechanics, governed by the equations of traditional hydrodynamics, and the relevant quasi-particles are the phonons. It must however be emphasized that this choice of example is only for the sake of pedagogical simplicity and that our considerations apply generically to wide classes of analogue spacetimes

  11. New active analogues of Cucurbita maxima trypsin inhibitor III (CMTI-III) modified in the non-contact region.

    Science.gov (United States)

    Rózycki, J; Kupryszewski, G; Rolka, K; Ragnarsson, U; Zbyryt, T; Krokoszyńska, I; Wilusz, T

    1994-01-01

    Four new analogues of trypsin inhibitor CMTI-III(3-28) = [desArg1,desVal2,desGly29]CMTI-III which was recently shown to be fully active, were synthesized by the solid-phase method. The introduction of glycine in position 9 (peptide 1) and Gly-Pro-Gly (peptide 2) and Gly-Pro-Asn (peptide 3) in the regions 17-19 and 23-25, respectively, did not change the antitrypsin activity of all modified peptides. All of these substitutions are presumed to be outside the trypsin-binding loop as judged from the X-ray structure of the complex between beta-trypsin and the related inhibitor CMTI-I. Also the fourth analogue which was substituted in all the positions mentioned, exhibited the full activity.

  12. Peptide chemistry toolbox - Transforming natural peptides into peptide therapeutics.

    Science.gov (United States)

    Erak, Miloš; Bellmann-Sickert, Kathrin; Els-Heindl, Sylvia; Beck-Sickinger, Annette G

    2018-06-01

    The development of solid phase peptide synthesis has released tremendous opportunities for using synthetic peptides in medicinal applications. In the last decades, peptide therapeutics became an emerging market in pharmaceutical industry. The need for synthetic strategies in order to improve peptidic properties, such as longer half-life, higher bioavailability, increased potency and efficiency is accordingly rising. In this mini-review, we present a toolbox of modifications in peptide chemistry for overcoming the main drawbacks during the transition from natural peptides to peptide therapeutics. Modifications at the level of the peptide backbone, amino acid side chains and higher orders of structures are described. Furthermore, we are discussing the future of peptide therapeutics development and their impact on the pharmaceutical market. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Quantification of pharmaceutical peptides using selenium as an elemental detection label

    DEFF Research Database (Denmark)

    Møller, Laura Hyrup; Gabel-Jensen, Charlotte; Franzyk, Henrik

    2014-01-01

    analysis of cell samples by LC-ICP-MS showed mainly uptake of the intact peptides, while the amount of intact peptides in cell lysates was semi-quantitatively determined. The selenium-containing penetratin analogues were to some extent degraded in pure cell medium, while an extensive degradation......The aim of the present work was to demonstrate how selenium labelling of a synthetic cell-penetrating peptide may be employed in evaluation of stability and quantitative estimation of cellular uptake by inductively coupled plasma mass spectrometry (ICP-MS). Two analogues of the cell...

  14. Cyclic cholecystokinin analogues with high selectivity for central receptors

    International Nuclear Information System (INIS)

    Charpentier, B.; Pelaprat, D.; Durieux, C.; Dor, A.; Roques, B.P.; Reibaud, M.; Blanchard, J.C.

    1988-01-01

    Taking as a model the N-terminal folding of the cholecystokinin tyrosine-sulfated octapeptide deduced from conformational studies, two cyclic cholecystokinin (CCK) analogues were synthesized by conventional peptide synthesis. The binding characteristics of these peptides were investigated on brain cortex membranes and pancreatic acini of guinea pig. Compounds I and II were competitive inhibitors of [ 3 H]Boc[Ahx 28,31 ]CCK-(27-33) binding to central CCK receptors and showed a high degree of selectivity for these binding sites. This high selectivity was associated with a high affinity for central CCK receptors. Similar affinities and selectivities were found when 125 I Bolton-Hunter-labeled CCK-8 was used as a ligand. Moreover, these compounds were only weakly active in the stimulation of amylase release from guinea pig pancreatic acini and were unable to induce contractions in the guinea pig ileum. The two cyclic CCK analogues, therefore, appear to be synthetic ligands exhibiting both high affinity and high selectivity for central CCK binding sites. These compounds could help clarify the respective role of central and peripheral receptors for various CCK-8-induced pharmacological effects

  15. Plasma Atrial Natriuretic Peptide as a non-invasive biochemical ...

    African Journals Online (AJOL)

    Plasma Atrial Natriuretic Peptide as a non-invasive biochemical marker of dyspnoea in congestive heart failure patients. ... University of Mauritius Research Journal ... score assessed by a 10 graded visual analogue scale in the control group (mean score = 1) and an increased from 1.6 to 6.4 in the heart failure patients.

  16. Status of natural analogue studies

    International Nuclear Information System (INIS)

    Sekine, Keiichi

    1994-03-01

    This report is based on the materials for the meeting at the Nuclear Safety Commission of Japan held on September 1993. Details are as follows: Alteration of glass as the study of alteration of natural minerals; alteration of uranium minerals, migration of uranium and thorium series radionuclides, alteration of chlorite, fixation of uranium alteration of minerals and migration of uranium as the study of alligator rivers analogue project held at Koongarra uranium deposit, Australia. (author)

  17. From boron analogues of amino acids to boronated DNA: potential new pharmaceuticals and neutron capture agents

    International Nuclear Information System (INIS)

    Spielvogel, B.F.; Sood, Anup; Duke Univ., Durham, NC; Shaw, B.R.; Hall, I.H.

    1991-01-01

    Isoelectronic and isostructural boron analogues of the α-amino acids ranging from simple glycine analogues such as H 3 NBH 2 COOH and Me 2 NHBH 2 COOH to alanine analogues have been synthesised. A diverse variety of analogues, including precursors and derivatives (such as peptides) have potent pharmacological activity, including anticancer, antiinflammatory, analgesic, and hypolipidemic activity in animal model studies and in vitro cell cultures. Boronated nucleosides and (oligo)nucleotides, synthetic oligonucleotide analogues of ''antisense'' agents interact with a complementary nucleic acid sequence blocking the biological effect of the target sequence. Nucleosides boronated on the pyrimidine and purine bases have been prepared. It has been established that an entirely new class of nucleic acid derivatives is feasible in which one of the non-bridging oxygens in the internucleotide phosphodiester linkage can be replaced by an isoelectronic analogue, the borane group, (BH 3 ). The boronated oligonucleotides can be viewed as hybrids of the normal oxygen oligonucleotides and the methylphosphonate oligonucleotides. (author)

  18. The in vivo disposition and in vitro transmembrane transport of two model radiometabolites of DOTA-conjugated receptor-specific peptides labelled with (177) Lu.

    Science.gov (United States)

    Volková, Marie; Mandíková, Jana; Bárta, Pavel; Navrátilová, Lucie; Lázníčková, Alice; Trejtnar, František

    2015-01-01

    In vivo metabolism of the radiolabelled receptor-specific peptides has been described; however, information regarding the pharmacokinetic behaviour of the degradation products within the body is very scarce. The present study was designed to obtain new knowledge on the disposition and elimination of low-molecular radiometabolites of receptor-specific peptides in the organism and to reveal the potential involvement of selected membrane transport mechanisms in the cellular uptake of radiometabolites, especially in the kidney. The study compared pharmacokinetics of two radiometabolites: a final metabolite of somatostatin analogues, (177)Lu-DOTA-DPhe, and a tripeptide metabolite of (177)Lu-DOTA-minigastrin 11, (177)Lu-DOTA-DGlu-Ala-Tyr. Their pharmacokinetics was compared with that of respective parent (177)Lu-radiopeptide. Both radiometabolites exhibited relative rapid clearing from most body tissues in rats in vivo along with predominant renal excretion. The long-term renal retention of the smaller radiometabolite (177)Lu-DOTA-DPhe was lower than that of (177)Lu-DOTA-DGlu-Ala-Tyr. An uptake of (177)Lu-DOTA-DPhe by human renal influx transporter organic cation transporter 2 was found in vitro in a cellular model. The study brings the first experimental data on the in vivo pharmacokinetics of radiometabolites of receptor-specific somatostatin and gastrin analogues. The found results may indicate a negative correlation between the degree of decomposition of the parent peptide chain and the renal retention of the metabolite. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Killing of Mycobacterium avium by lactoferricin peptides: improved activity of arginine- and D-amino-acid-containing molecules.

    Science.gov (United States)

    Silva, Tânia; Magalhães, Bárbara; Maia, Sílvia; Gomes, Paula; Nazmi, Kamran; Bolscher, Jan G M; Rodrigues, Pedro N; Bastos, Margarida; Gomes, Maria Salomé

    2014-06-01

    Mycobacterium avium causes respiratory disease in susceptible individuals, as well as disseminated infections in immunocompromised hosts, being an important cause of morbidity and mortality among these populations. Current therapies consist of a combination of antibiotics taken for at least 6 months, with no more than 60% overall clinical success. Furthermore, mycobacterial antibiotic resistance is increasing worldwide, urging the need to develop novel classes of antimicrobial drugs. One potential and interesting alternative strategy is the use of antimicrobial peptides (AMP). These are present in almost all living organisms as part of their immune system, acting as a first barrier against invading pathogens. In this context, we investigated the effect of several lactoferrin-derived AMP against M. avium. Short peptide sequences from both human and bovine lactoferricins, namely, hLFcin1-11 and LFcin17-30, as well as variants obtained by specific amino acid substitutions, were evaluated. All tested peptides significantly inhibited the axenic growth of M. avium, the bovine peptides being more active than the human. Arginine residues were found to be crucial for the display of antimycobacterial activity, whereas the all-d-amino-acid analogue of the bovine sequence displayed the highest mycobactericidal activity. These findings reveal the promising potential of lactoferricins against mycobacteria, thus opening the way for further research on their development and use as a new weapon against mycobacterial infections. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  20. Cancer therapy with alpha-emitters labeled peptides.

    Science.gov (United States)

    Dadachova, Ekaterina

    2010-05-01

    Actively targeted alpha-particles offer specific tumor cell killing action with less collateral damage to surrounding normal tissues than beta-emitters. During the last decade, radiolabeled peptides that bind to different receptors on the tumors have been investigated as potential therapeutic agents both in the preclinical and clinical settings. Advantages of radiolabeled peptides over antibodies include relatively straightforward chemical synthesis, versatility, easier radiolabeling, rapid clearance from the circulation, faster penetration and more uniform distribution into tissues, and less immunogenicity. Rapid internalization of the radiolabeled peptides with equally rapid re-expression of the cell surface target is a highly desirable property that enhances the total delivery of these radionuclides into malignant sites. Peptides, such as octreotide, alpha-melanocyte-stimulating hormone analogues, arginine-glycine-aspartic acid-containing peptides, bombesin derivatives, and others may all be feasible for use with alpha-emitters. The on-going preclinical work has primarily concentrated on octreotide and octreotate analogues labeled with Bismuth-213 and Astatine-211. In addition, alpha-melanocyte-stimulating hormone analogue has been labeled with Lead-212/Bismuth-212 in vivo generator and demonstrated the encouraging therapeutic efficacy in treatment of experimental melanoma. Obstacles that continue to obstruct widespread acceptance of alpha-emitter-labeled peptides are primarily the supply of these radionuclides and concerns about potential kidney toxicity. New sources and methods for production of these medically valuable radionuclides and better understanding of mechanisms related to the peptide renal uptake and clearance should speed up the introduction of alpha-emitter-labeled peptides into the clinic. Copyright 2010 Elsevier Inc. All rights reserved.

  1. Binding affinities of insulin analogues substituted at the position B26 with glutamine, asparagine and aspartic acid

    Czech Academy of Sciences Publication Activity Database

    Antolíková, Emília; Žáková, Lenka; Jiráček, Jiří

    2010-01-01

    Roč. 16, S1 (2010), s. 162-162 ISSN 1075-2617. [European Peptide Symposium /31./. 05.09.2010-09.09.2010, Copenhagen] Institutional research plan: CEZ:AV0Z40550506 Keywords : insulin * insulin analogues * diabetes Subject RIV: CC - Organic Chemistry

  2. Climate Analogues for agricultural impact projection and adaptation – a reliability test

    Directory of Open Access Journals (Sweden)

    Swen P.M. Bos

    2015-10-01

    Full Text Available The climate analogue approach is often considered a valuable tool for climate change impact projection and adaptation planning, especially for complex systems that cannot be modelled reliably. Important examples are smallholder farming systems using agroforestry or other mixed-cropping approaches. For the projected climate at a particular site of interest, the analogue approach identifies locations where the current climate is similar to these projected conditions. By comparing baseline-analogue site pairs, information on climate impacts and opportunities for adaptation can be obtained. However, the climate analogue approach is only meaningful, if climate is a dominant driver of differences between baseline and analogue site pairs. For a smallholder farming setting on Mt. Elgon in Kenya, we tested this requirement by comparing yield potentials of maize and coffee (obtained from the IIASA Global Agro-ecological Zones dataset among 50 close analogue sites for different future climate scenarios and models, and by comparing local ecological knowledge and farm characteristics for one baseline-analogue pair.Yield potentials among the 50 closest analogue locations varied strongly within all climate scenarios, hinting at factors other than climate as major drivers of what the analogue approach might interpret as climate effects. However, on average future climatic conditions seemed more favourable to maize and coffee cultivation than current conditions. The detailed site comparison revealed substantial differences between farms in important characteristics, such as farm size and presence of cash crops, casting doubt on the usefulness of the comparison for climate change analysis. Climatic constraints were similar between sites, so that no apparent lessons for adaptation could be derived. Pests and diseases were also similar, indicating that climate change may not lead to strong changes in biotic constraints at the baseline site in the near future. From

  3. Radiolabelled peptides for tumour therapy: current status and future directions. Plenary lecture at the EANM 2002

    International Nuclear Information System (INIS)

    Jong, Marion de; Kwekkeboom, Dik; Valkema, Roelf; Krenning, Eric P.

    2003-01-01

    On their plasma membranes, cells express receptor proteins with high affinity for regulatory peptides, such as somatostatin. Changes in the density of these receptors during disease, e.g. overexpression in many tumours, provide the basis for new imaging methods. The first peptide analogues successfully applied for visualisation of receptor-positive tumours were radiolabelled somatostatin analogues. The next step was to label these analogues with therapeutic radionuclides for peptide receptor radionuclide therapy (PRRT). Results from preclinical and clinical multicentre studies have already shown an effective therapeutic response when using radiolabelled somatostatin analogues to treat receptor-positive tumours. Infusion of positively charged amino acids reduces kidney uptake, enlarging the therapeutic window. For PRRT of CCK-B receptor-positive tumours, such as medullary thyroid carcinoma, radiolabelled minigastrin analogues are currently being successfully applied. The combination of different therapy modalities holds interest as a means of improving the clinical therapeutic effects of radiolabelled peptides. The combination of different radionuclides, such as 177 Lu- and 90 Y-labelled somatostatin analogues, to reach a wider tumour region of high curability, has been described. A variety of other peptide-based radioligands, such as bombesin and NPY(Y 1 ) analogues, receptors for which are expressed on common cancers such as prostate and breast cancer, are currently under development and in different phases of (pre)clinical investigation. Multi-receptor tumour targeting using the combination of bombesin and NPY(Y 1 ) analogues is promising for scintigraphy and PRRT of breast carcinomas and their lymph node metastases. (orig.)

  4. Radio peptide imaging and therapy

    International Nuclear Information System (INIS)

    Buscombe, Jonh

    1997-01-01

    Full text. The concept of the magic bullet retains its attraction to us. If only we could take a drug or radioisotope and inject this intravenously and then will attach to the target cancer. This may allow imaging if labelled with a radio pharmaceutical or possibly even effective therapy. Initially work was started using antibodies of mouse origin. These have shown some utility in targeting tumors but there are problems in that these are essentially non-human proteins, often derived from mice. This leads to the formation of antibodies against that antibody so that repeat administrations lead to reduced efficacy and possibly may carry a risk anaphylaxis for the patient. Two different methods have evolved to deal with this situation. Either make antibodies more human or use smaller fragments, so that they are less likely to cause allergic reactions. The second method is to try and use a synthetic peptide. This will contain a series of amino acids which recognize a certain cell receptor. For example the somatostatin analogue Octreotide is an 8 amino acid peptide which has the same biological actions as natural somatostatin but an increased plasma half life. To this is added a linker a good example being DTPA and then radioisotope for example In-111. There we can have the complex In-111-DTPA-Octreotide which can be used to image somatostatin receptors in vivo. The main advantage over antibodies is that the cost production is less and many different variation of peptides for a particular receptor can be manufactured and assessed to find which is the optimal agent tumour imaging at a fraction of the cost of antibody production. There are two main approaches. Firstly to take a natural peptide hormone such as insulin or VIP and label by a simple method such as iodination with I-123. A group in Vienna have done it and shown good uptake of I-123 Insulin in primary hepatomas and of I-123 VIP in pancreatic cancers. Many natural peptide hormones however have a short plasma half

  5. Design of a saturated analogue and digital current transducer

    International Nuclear Information System (INIS)

    Pross, Alexander

    2002-01-01

    technique. The analogue input signal was recovered at the digital output, by passing the signal through a low pass filter, which acts as an averaging device. Analyses revealed that the developed transducer operated as a pulse code modulator (PCM), providing evidence that it is in effect a first order sigma- delta modulator. The accuracy of the new analogue and digital transducer was found to depend on a number of factors, including the primary and secondary windings and the current sense resistor. Whilst the overall accuracy, was estimated to be ±2 %, and was considered to be good, there are a number of remaining challenges. This is also noted as items for further work. (author)

  6. Stereochemistry Balances Cell Permeability and Solubility in the Naturally Derived Phepropeptin Cyclic Peptides.

    Science.gov (United States)

    Schwochert, Joshua; Lao, Yongtong; Pye, Cameron R; Naylor, Matthew R; Desai, Prashant V; Gonzalez Valcarcel, Isabel C; Barrett, Jaclyn A; Sawada, Geri; Blanco, Maria-Jesus; Lokey, R Scott

    2016-08-11

    Cyclic peptide (CP) natural products provide useful model systems for mapping "beyond-Rule-of-5" (bRo5) space. We identified the phepropeptins as natural product CPs with potential cell permeability. Synthesis of the phepropeptins and epimeric analogues revealed much more rapid cellular permeability for the natural stereochemical pattern. Despite being more cell permeable, the natural compounds exhibited similar aqueous solubility as the corresponding epimers, a phenomenon explained by solvent-dependent conformational flexibility among the natural compounds. When analyzing the polarity of the solution structures we found that neither the number of hydrogen bonds nor the total polar surface area accurately represents the solvation energies of the high and low dielectric conformations. This work adds to a growing number of natural CPs whose solvent-dependent conformational behavior allows for a balance between aqueous solubility and cell permeability, highlighting structural flexibility as an important consideration in the design of molecules in bRo5 chemical space.

  7. Natural and archaeological analogues: a review

    International Nuclear Information System (INIS)

    Brookins, D.G.

    1987-01-01

    In this chapter natural analogues in the geomedia for various aspects of radioactive waste disposal are discussed. Particular reference is made to the Okla Natural Reactor in Gabon. Igneous contact zones are discussed and natural analogues of waste-form materials. The importance of archaeological remains and anthropogenic materials left by man, in assessing weathering conditions and serving as radioactive waste analogues, is also emphasised. (UK)

  8. DOTA-derivatives of octreotide dicarba-analogues with high affinity for somatostatin sst2,5 receptors

    Science.gov (United States)

    Pratesi, Alessandro; Ginanneschi, Mauro; Lumini, Marco; Papini, Anna M.; Novellino, Ettore; Brancaccio, Diego; Carotenuto, Alfonso

    2017-02-01

    In vivo somatostatin receptor scintigraphy is a valuable method for the visualization of human endocrine tumours and their metastases. In fact, peptide ligands of somatostatin receptors (sst’s) conjugated with chelating agents are in clinical use. We have recently developed octreotide dicarba-analogues, which show interesting binding profiles at sst’s. In this context, it was mandatory to explore the possibility that our analogues could maintain their activity also upon conjugation with DOTA. In this paper, we report and discuss the synthesis, binding affinity and conformational preferences of three DOTA-conjugated dicarba-analogues of octreotide. Interestingly, two conjugated analogues exhibited nanomolar affinities on sst2 and sst5 somatostatin receptor subtypes.

  9. Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

    Directory of Open Access Journals (Sweden)

    Patrick Rabe

    2014-08-01

    Full Text Available Tropodithietic acid (TDA is a structurally unique sulfur-containing antibiotic from the Roseobacter clade bacterium Phaeobacter inhibens DSM 17395 and a few other related species. We have synthesised several structural analogues of TDA and used them in bioactivity tests against Staphylococcus aureus and Vibrio anguillarum for a structure–activity relationship (SAR study, revealing that the sulfur-free analogue of TDA, tropone-2-carboxylic acid, has an antibiotic activity that is even stronger than the bioactivity of the natural product. The synthesis of this compound and of several analogues is presented and the bioactivity of the synthetic compounds is discussed.

  10. The Valles natural analogue project

    International Nuclear Information System (INIS)

    Stockman, H.; Krumhansl, J.; Ho, C.; McConnell, V.

    1994-12-01

    The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a highlevel waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, X-ray diffraction; and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and 39 Ar/ 4O isotopic composition. Overall,the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 meters of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks

  11. Binding, folding and insertion of a β-hairpin peptide at a lipid bilayer surface: Influence of electrostatics and lipid tail packing.

    Science.gov (United States)

    Reid, Keon A; Davis, Caitlin M; Dyer, R Brian; Kindt, James T

    2018-03-01

    Antimicrobial peptides (AMPs) act as host defenses against microbial pathogens. Here we investigate the interactions of SVS-1 (KVKVKVKV d P l PTKVKVKVK), an engineered AMP and anti-cancer β-hairpin peptide, with lipid bilayers using spectroscopic studies and atomistic molecular dynamics simulations. In agreement with literature reports, simulation and experiment show preferential binding of SVS-1 peptides to anionic over neutral bilayers. Fluorescence and circular dichroism studies of a Trp-substituted SVS-1 analogue indicate, however, that it will bind to a zwitterionic DPPC bilayer under high-curvature conditions and folds into a hairpin. In bilayers formed from a 1:1 mixture of DPPC and anionic DPPG lipids, curvature and lipid fluidity are also observed to promote deeper insertion of the fluorescent peptide. Simulations using the CHARMM C36m force field offer complementary insight into timescales and mechanisms of folding and insertion. SVS-1 simulated at an anionic mixed POPC/POPG bilayer folded into a hairpin over a microsecond, the final stage in folding coinciding with the establishment of contact between the peptide's valine sidechains and the lipid tails through a "flip and dip" mechanism. Partial, transient folding and superficial bilayer contact are seen in simulation of the peptide at a zwitterionic POPC bilayer. Only when external surface tension is applied does the peptide establish lasting contact with the POPC bilayer. Our findings reveal the influence of disruption to lipid headgroup packing (via curvature or surface tension) on the pathway of binding and insertion, highlighting the collaborative effort of electrostatic and hydrophobic interactions on interaction of SVS-1 with lipid bilayers. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Superior Antifouling Performance of a Zwitterionic Peptide Compared to an Amphiphilic, Non-Ionic Peptide.

    Science.gov (United States)

    Ye, Huijun; Wang, Libing; Huang, Renliang; Su, Rongxin; Liu, Boshi; Qi, Wei; He, Zhimin

    2015-10-14

    The aim of this study was to explore the influence of amphiphilic and zwitterionic structures on the resistance of protein adsorption to peptide self-assembled monolayers (SAMs) and gain insight into the associated antifouling mechanism. Two kinds of cysteine-terminated heptapeptides were studied. One peptide had alternating hydrophobic and hydrophilic residues with an amphiphilic sequence of CYSYSYS. The other peptide (CRERERE) was zwitterionic. Both peptides were covalently attached onto gold substrates via gold-thiol bond formation. Surface plasmon resonance analysis results showed that both peptide SAMs had ultralow or low protein adsorption amounts of 1.97-11.78 ng/cm2 in the presence of single proteins. The zwitterionic peptide showed relatively higher antifouling ability with single proteins and natural complex protein media. We performed molecular dynamics simulations to understand their respective antifouling behaviors. The results indicated that strong surface hydration of peptide SAMs contributes to fouling resistance by impeding interactions with proteins. Compared to the CYSYSYS peptide, more water molecules were predicted to form hydrogen-bonding interactions with the zwitterionic CRERERE peptide, which is in agreement with the antifouling test results. These findings reveal a clear relation between peptide structures and resistance to protein adsorption, facilitating the development of novel peptide-containing antifouling materials.

  13. Highly potent analogues of luteinizing hormone-releasing hormone containing D-phenylalanine nitrogen mustard in position 6.

    Science.gov (United States)

    Bajusz, S; Janaky, T; Csernus, V J; Bokser, L; Fekete, M; Srkalovic, G; Redding, T W; Schally, A V

    1989-08-01

    The nitrogen mustard derivatives of 4-phenylbutyric acid and L-phenylalanine, called chlorambucil (Chl) and melphalan (Mel), respectively, have been incorporated into several peptide hormones, including luteinizing hormone-releasing hormone (LH-RH). The alkylating analogues of LH-RH were prepared by linking Chl, as an N-acyl moiety, to the complete amino acid sequence of agonistic and antagonistic analogues. These compounds, in particular the antagonistic analogues, showed much lower potency than their congeners carrying other acyl groups. To obtain highly potent alkylating analogues of LH-RH, the D enantiomer of Mel was incorporated into position 6 of the native hormone and some of its antagonistic analogues. Of the peptides prepared, [D-Mel6]LH-RH (SB-05) and [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Pal(3)3,Arg5,D-Mel6,D-Ala10++ +]LH-RH [SB-86, where Nal(2) is 3-(2-naphthyl)alanine and Pal(3) is 3-(3-pyridyl)alanine] possessed the expected high agonistic and antagonistic activities, respectively, and also showed high affinities for the membrane receptors of rat pituitary cells, human breast cancer cells, human prostate cancer cells, and rat Dunning R-3327 prostate tumor cells. These two analogues exerted cytotoxic effects on human and rat mammary cancer cells in vitro. Thus these two D-Mel6 analogues seem to be particularly suitable for the study of how alkylating analogues of LH-RH could interfere with intracellular events in certain cancer cells.

  14. Highly potent analogues of luteinizing hormone-releasing hormone containing D-phenylalanine nitrogen mustard in position 6

    International Nuclear Information System (INIS)

    Bajusz, S.; Janaky, T.; Csernus, V.J.; Bokser, L.; Fekete, M.; Srkalovic, G.; Redding, T.W.; Schally, A.V.

    1989-01-01

    The nitrogen mustard derivatives of 4-phenylbutyric acid and L-phenylalanine, called chlorambucil (Chl) and melphalan (Mel), respectively, have been incorporated into several peptide hormones, including luteinizing hormone-releasing hormone (LH-RH). The alkylating analogues of LH-RH were prepared by linking Chl, as an N-acyl moiety, to the complete amino acid sequence of agonistic and antagonistic analogues. These compounds, in particular the antagonistic analogues, showed much lower potency than their congeners carrying other acyl groups. To obtain highly potent alkylating analogues of LH-RH, the D enantiomer of Mel was incorporated into position 6 of the native hormone and some of its antagonistic analogues. Of the peptides prepared, [D-Mel 6 ]LH-RH (SB-05) and [Ac-D-Nal(2) 1 ,D-Phe(pCl) 2 ,D-Pal(3) 3 ,Arg 5 ,D-Mel 6 ,D-Ala 10 ]LH-RH [SB-86, where Nal(2) is 3-(2-naphthyl)alanine and Pal(3) is 3-(3-pyridyl)alanine] possessed the expected high agonistic and antagonistic activities, respectively, and also showed high affinities for the membrane receptors of rat pituitary cells, human breast cancer cells, human prostate cancer cells, and rat Dunning R-3327 prostate tumor cells. These two analogues exerted cytotoxic effects on human and rat mammary cancer cells in vitro. Thus these two D-Mel 6 analogues seem to be particularly suitable for the study of how alkylating analogues of LH-RH could interfere with intracellular events in certain cancer cells

  15. 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, wh...

  16. Eco-Friendly Insecticide Discovery via Peptidomimetics: Design, Synthesis, and Aphicidal Activity of Novel Insect Kinin Analogues.

    Science.gov (United States)

    Zhang, Chuanliang; Qu, Yanyan; Wu, Xiaoqing; Song, Dunlun; Ling, Yun; Yang, Xinling

    2015-05-13

    Insect kinin neuropeptides are pleiotropic peptides that are involved in the regulation of hindgut contraction, diuresis, and digestive enzyme release. They share a common C-terminal pentapeptide sequence of Phe(1)-Xaa(2)-Yaa(3)-Trp(4)-Gly(5)-NH2 (where Xaa(2) = His, Asn, Phe, Ser, or Tyr; Yaa(3) = Pro, Ser, or Ala). Recently, the aphicidal activity of insect kinin analogues has attracted the attention of researchers. Our previous work demonstrated that the sequence-simplified insect kinin pentapeptide analogue Phe-Phe-[Aib]-Trp-Gly-NH2 could retain good aphicidal activity and be the lead compound for the further discovery of eco-friendly insecticides which encompassed a broad array of biochemicals derived from micro-organisms and other natural sources. Using the peptidomimetics strategy, we chose Phe-Phe-[Aib]-Trp-Gly-NH2 as the lead compound, and we designed and synthesized three series, including 31 novel insect kinin analogues. The aphicidal activity of the new analogues against soybean aphid was determined. The results showed that all of the analogues exhibited aphicidal activity. Of particular interest was the analogue II-1, which exhibited improved aphicidal activity with an LC50 of 0.019 mmol/L compared with the lead compound (LC50 = 0.045 mmol/L) or the commercial insecticide pymetrozine (LC50 = 0.034 mmol/L). This suggests that the analogue II-1 could be used as a new lead for the discovery of potential eco-friendly insecticides.

  17. New Insights in the Design of Bioactive Peptides and Chelating Agents for Imaging and Therapy in Oncology

    Directory of Open Access Journals (Sweden)

    Anna Lucia Tornesello

    2017-08-01

    Full Text Available Many synthetic peptides have been developed for diagnosis and therapy of human cancers based on their ability to target specific receptors on cancer cell surface or to penetrate the cell membrane. Chemical modifications of amino acid chains have significantly improved the biological activity, the stability and efficacy of peptide analogues currently employed as anticancer drugs or as molecular imaging tracers. The stability of somatostatin, integrins and bombesin analogues in the human body have been significantly increased by cyclization and/or insertion of non-natural amino acids in the peptide sequences. Moreover, the overall pharmacokinetic properties of such analogues and others (including cholecystokinin, vasoactive intestinal peptide and neurotensin analogues have been improved by PEGylation and glycosylation. Furthermore, conjugation of those peptide analogues to new linkers and bifunctional chelators (such as AAZTA, TETA, TRAP, NOPO etc., produced radiolabeled moieties with increased half life and higher binding affinity to the cognate receptors. This review describes the most important and recent chemical modifications introduced in the amino acid sequences as well as linkers and new bifunctional chelators which have significantly improved the specificity and sensitivity of peptides used in oncologic diagnosis and therapy.

  18. Atomic Force Microscopy and MD Simulations Reveal Pore-Like Structures of All-D-Enantiomer of Alzheimer’s β-Amyloid Peptide: Relevance to the Ion Channel Mechanism of AD Pathology

    Science.gov (United States)

    Connelly, Laura; Arce, Fernando Teran; Jang, Hyunbum; Capone, Ricardo; Kotler, Samuel A.; Ramachandran, Srinivasan; Kagan, Bruce L.; Nussinov, Ruth; Lal, Ratnesh

    2012-01-01

    Alzheimer’s disease (AD) is a protein misfolding disease characterized by a build-up of β-amyloid (Aβ) peptide as senile plaques, uncontrolled neurodegeneration, and memory loss. AD pathology is linked to the destabilization of cellular ionic homeostasis and involves Aβ peptide-plasma membrane interactions. In principle, there are two possible ways through which disturbance of the ionic homeostasis can take place: directly, where the Aβ peptide either inserts into the membrane and creates ion-conductive pores or destabilizes the membrane organization; or, indirectly, where the Aβ peptide interacts with existing cell membrane receptors. To distinguish between these two possible types of Aβ-membrane interactions, we took advantage of the biochemical tenet that ligand-receptor interactions are stereospecific; L-amino acid peptides, but not their D-counterparts, bind to cell membrane receptors. However, with respect to the ion channel-mediated mechanism, like L-amino acids, D-amino acid peptides will also form ion channel-like structures. Using atomic force microscopy (AFM) we imaged the structures of both D- and L-enantiomers of the full length Aβ1-42 when reconstituted in lipid bilayers. AFM imaging shows that both L- and D-Aβ isomers form similar channel-like structures. Molecular dynamics (MD) simulations support the AFM imaged 3D structures. Earlier we have shown that D-Aβ1-42 channels conduct ions similarly to their L-counter parts. Taken together, our results support the direct mechanism of Aβ ion channel-mediated destabilization of ionic homeostasis rather than the indirect mechanism through Aβ interaction with membrane receptors. PMID:22217000

  19. Neurochemical binding profiles of novel indole and benzofuran MDMA analogues.

    Science.gov (United States)

    Shimshoni, Jakob A; Winkler, Ilan; Golan, Ezekiel; Nutt, David

    2017-01-01

    3,4-Methylenedioxy-N-methylamphetamine (MDMA) has been shown to be effective in the treatment of post-traumatic stress disorder (PTSD) in numerous clinical trials. In the present study, we have characterized the neurochemical binding profiles of three MDMA-benzofuran analogues (1-(benzofuran-5-yl)-propan-2-amine, 5-APB; 1-(benzofuran-6-yl)-N-methylpropan-2-amine, 6-MAPB; 1-(benzofuran-5-yl)-N-methylpropan-2-amine, 5-MAPB) and one MDMA-indole analogue (1-(1H-indol-5-yl)-2-methylamino-propan-1-ol, 5-IT). These compounds were screened as potential second-generation anti-PTSD drugs, against a battery of human and non-human receptors, transporters, and enzymes, and their potencies as 5-HT 2 receptor agonist and monoamine uptake inhibitors determined. All MDMA analogues displayed high binding affinities for 5-HT 2a,b,c and NE α2 receptors, as well as significant 5-HT, DA, and NE uptake inhibition. 5-APB revealed significant agonist activity at the 5-HT 2a,b,c receptors, while 6-MAPB, 5-MAPB, and 5-IT exhibited significant agonist activity at the 5-HT 2c receptor. There was a lack of correlation between the results of functional uptake and the monoamine transporter binding assay. MDMA analogues emerged as potent and selective monoamine oxidase A inhibitors. Based on 6-MAPB favorable pharmacological profile, it was further subjected to IC 50 determination for monoamine transporters. Overall, all MDMA analogues displayed higher monoamine receptor/transporter binding affinities and agonist activity at the 5-HT 2a,c receptors as compared to MDMA.

  20. NTS1-R-targeted diagnostic imaging of malignant tumors with 99mTc labeled neurotensin analogues

    International Nuclear Information System (INIS)

    Nikolopoulou, A.; Nock, B.; Maina, T.; Galanis, A.; Cordopatis, P.

    2004-01-01

    Full text: Recent studies, based on receptor radio autoradiography methods in human biopsy specimens, have demonstrated the expression of neurotensin receptors of subtype 1 (NTSI-R) at a high density in primary human cancers, such as in ductal exocrine pancreatic carcinoma, Ewing's sarcoma and meningioma. This finding provides the molecular basis for the scintigraphic detection of NTS1-R-positive tumors in patients using radiolabeled NT analogues in combination with SPECT. We synthesized two novel NT analogues based on the NT (8-13) peptide sequence - essential for interaction with the NTS1-R - and modified at the N-terminal by a covalently attached open chain tetraamine chelator for stable binding of the radionuclide. In this work, a comparative study of the new compounds in cells and animal models is presented and their suitability in the NTS1-R- targeted diagnostic imaging of malignant tumors is discussed. In particular, the tetra-amine functional analogues NT1: [N4- (a) Ala0, Dab9] NT (8-13) and NT2: [N4- (a) Ala0, Dab9, Tle12] NT (8-13) were synthesized by SPPS techniques applying Fmoc/Boc protection strategies. The ES-MS spectra of the chromatographically purified products were consistent with the expected formulae. Incorporation of the radiometal (99mTc) by the open chain tetraamine framework proceeded different at room temperature in alkaline aqueous medium using SnCl2 as reducing agent in the presence of citrate. Under the above mild conditions labelling was nearly quantitative leading to single radiopeptide species of high specific activity. During competition binding assays in human colon adenocarcinoma WiDr cell membranes, using [125I-Tyr3] NT as the radioligand, both peptide conjugates demonstrated high affinity binding to the NTS1-R with IC50s 30 and 80 pM, respectively (IC50 for native NT= 0.20 nM). Both radiopeptides showed a rapid and NTS1-R-mediated migration into the intracellular compartment of the same cells reaching a 95% internalization

  1. Recombinant erythropoietin and analogues: a challenge for doping control.

    Science.gov (United States)

    Pascual, J A; Belalcazar, V; de Bolos, C; Gutiérrez, R; Llop, E; Segura, J

    2004-04-01

    Erythropoietin (EPO) increases the number of circulating erythrocytes and thus muscle oxygenation. The availability of the recombinant protein (rEPO) has increased the risk of its illegal use in sports, its detection being a difficult challenge. Five different hematopoietic parameters were initially chosen as indirect markers of rEPO abuse: concentration of serum EPO, concentration of serum-soluble transferrin receptors (sTFr), hematocrit, percentage of reticulocytes, and percentage of macrocytes. New models considering only hemoglobin, serum EPO concentration, and percentage of reticulocytes are simpler and seem to be more sensitive when low doses of rEPO are used. A more direct method of urine analysis (isoelectrofocusing, double blotting, and chemiluminescent detection) based on the charge differences between rEPO and endogenous EPO, related to their carbohydrate composition, provides proof of rEPO use. Furthermore, this approach permits the detection of darbepoetin, a direct analogue of EPO also known as NESP ("new erythropoiesis stimulating protein"). Recently a protein conjugate, "synthetic erythropoiesis protein" (SEP), containing precision-length, monodisperse, negatively charged polymers instead of oligosaccharides has been synthesized. Finally, EPO-mimetics are molecules capable of acting as EPO in dimerizing the EPO receptor. Two kinds of EPO-mimetics have been described: peptides and nonpeptides. The enhancement of oxygen availability to muscles by rEPO, analogues, and mimetics constitutes one of the main challenges to doping control. Major steps have already been developed for detection ofrEPO and some analogues. In the near future, the transfection to an athlete's body of genes that code for erythropoietin might be an emerging doping issue, and sports authorities have incorporated "gene doping" among the prohibited practices.

  2. CO2 Capture with Enzyme Synthetic Analogue

    Energy Technology Data Exchange (ETDEWEB)

    Cordatos, Harry

    2010-11-08

    Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.

  3. Synthesis and anticancer evaluation of spermatinamine analogues

    KAUST Repository

    Moosa, Basem; Sagar, Sunil; Li, Song; Esau, Luke; Kaur, Mandeep; Khashab, Niveen M.

    2016-01-01

    analogues and their cytotoxic evaluation against three human cancer cell lines i.e. cervix adenocarcinoma (HeLa), breast adenocarcinoma (MCF-7), and prostate carcinoma (DU145). Analogues 12, 14 and 15 were found to be the most potent against one or more cell

  4. Liraglutide: a once-daily GLP-1 analogue for the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, Tina

    2007-01-01

    properties that are suitable for once-daily dosing. Liraglutide has demonstrated lasting improvement of HbA(1c )levels, weight reduction and improved beta-cell function in patients with Type 2 diabetes mellitus. Liraglutide is well tolerated; the adverse events that are most frequently reported being...... transient nausea and diarrhoea. This article reviews the mechanisms of action and efficacy of liraglutide for the treatment of Type 2 diabetes mellitus. This agent is presently in Phase III clinical development.......The incretin hormones are intestinal peptides that enhance insulin secretion following ingestion of nutrients. Liraglutide is a glucagon-like peptide-1 receptor analogue, which is obtained by derivatising glucagon-like peptide-1 with a fatty acid, providing a compound with pharmacokinetic...

  5. Liraglutide: a once-daily GLP-1 analogue for the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, Tina

    2007-01-01

    The incretin hormones are intestinal peptides that enhance insulin secretion following ingestion of nutrients. Liraglutide is a glucagon-like peptide-1 receptor analogue, which is obtained by derivatising glucagon-like peptide-1 with a fatty acid, providing a compound with pharmacokinetic propert...... transient nausea and diarrhoea. This article reviews the mechanisms of action and efficacy of liraglutide for the treatment of Type 2 diabetes mellitus. This agent is presently in Phase III clinical development....... properties that are suitable for once-daily dosing. Liraglutide has demonstrated lasting improvement of HbA(1c )levels, weight reduction and improved beta-cell function in patients with Type 2 diabetes mellitus. Liraglutide is well tolerated; the adverse events that are most frequently reported being...

  6. Stereoselective Preparation of N-Alkyl Dipeptide Analogues via Dynamic Kinetic Resolution of α-Halo Acyl Amino Esters

    International Nuclear Information System (INIS)

    Shin, Eun Kyoung; Chang, Ji Yeon; Kim, Hyun Jung; Kim, Yong Tae; Park, Yong Sun

    2006-01-01

    We have shown that dynamic kinetic resolution of α-bromo and α-chloro amides in nucleophilic substitution reaction can be successfully applied towards the preparation of various N-terminal functionalized dipeptide analogues. The stereochemical aspects of the results showed that stereoselectivity depends critically on the structures of amine nucleophiles. This mild and practical method can be run on a multi-gram scale without any special precautions and should be applicable to stereoselective syntheses of various peptidomimetics. Extension of this synthetic methodology to dynamic resolution of N-(α-haloacetyl) peptides in the stereospecific nucleophilic substitution (S N 2) could be an attractive synthetic strategy for asymmetric syntheses of peptide analogues. Recently it has been shown from our group that the chiral information of adjacent amino acid residue is efficiently transferred to the new C-N bond formation at α-halo carbon center for asymmetric syntheses of di-, tri- and tetrapeptide analogues. The α-halo stereogenic center of undergoes rapid epimerization in the presence of diisopropylethylamine (DIEA) and tetrabutylammonium iodide (TBAI), and (αS) reacts with the nucleophile preferentially to provide the dipeptide analogue (αR). The mechanistic investigation showed that this is a case of dynamic kinetic resolution, in which the stereoselectivity is determined by the difference in the diastereomeric transition state energies for the reaction with the nucleophiles. Herein we describe our recent progress to extend the scope of the methodology to stereoselective preparation of N-terminal functionalized dipeptide analogues with various amine nucleophiles

  7. Chemical construction and structural permutation of potent cytotoxin polytheonamide B: discovery of artificial peptides with distinct functions.

    Science.gov (United States)

    Itoh, Hiroaki; Inoue, Masayuki

    2013-07-16

    Polytheonamide B (1), isolated from the marine sponge Theonella swinhoei, is a posttranslationally modified ribosomal peptide (MW 5030 Da) that displays extraordinary cytotoxicity. Among its 48 amino acid residues, this peptide includes a variety D- and L-amino acids that do not occur in proteins, and the chiralities of these amino acids alternate in sequence. These structural features induce the formation of a stable β6.3-helix, giving rise to a tubular structure of over 4 nm in length. In the biological setting, this fold is believed to transport cations across the lipid bilayer through a pore, thereby acting as an ion channel. In this Account, we discuss the construction and structural permutations of this potent cytotoxin. First we describe the 161-step chemical construction of this unusual peptide 1. By developing a synthetic route to 1, we established the chemical basis for subsequent SAR studies to pinpoint the proteinogenic and nonproteinogenic building blocks within the molecule that confer its toxicity and channel function. Using fully synthetic 1, we generated seven analogues with point mutations, and studies of their activity revealed the importance of the N-terminal moiety. Next, we simplified the structure of 1 by substituting six amino acid residues of 1 to design a more synthetically accessible analogue 9. This dansylated polytheonamide mimic 9 was synthesized in 127 total steps, and we evaluated its function to show that it can emulate the toxic and ion channel activities of 1 despite its multiple structural modifications. Finally, we applied a highly automated synthetic route to 48-mer 9 to generate 13 substructures of 27-39-mers. The 37-mer 12 exhibited nanomolar level toxicity through a potentially distinct mode of action from 1 and 9. The SAR studies of polytheonamide B and the 21 artificial analogues have deepened our understanding of the precise structural requirements for the biological functions of 1. They have also led to the discovery of

  8. Pleomorphic copper coordination by Alzheimer's disease amyloid-beta peptide.

    Science.gov (United States)

    Drew, Simon C; Noble, Christopher J; Masters, Colin L; Hanson, Graeme R; Barnham, Kevin J

    2009-01-28

    Numerous conflicting models have been proposed regarding the nature of the Cu(2+) coordination environment of the amyloid beta (Abeta) peptide, the causative agent of Alzheimer's disease. This study used multifrequency CW-EPR spectroscopy to directly resolve the superhyperfine interactions between Cu(2+) and the ligand nuclei of Abeta, thereby avoiding ambiguities associated with introducing point mutations. Using a library of Abeta16 analogues with site-specific (15)N-labeling at Asp1, His6, His13, and His14, numerical simulations of the superhyperfine resonances delineated two independent 3N1O Cu(2+) coordination modes, {N(a)(D1), O, N(epsilon)(H6), N(epsilon)(H13)} (component Ia) and {N(a)(D1), O, N(epsilon)(H6), N(epsilon)(H14)} (component Ib), between pH 6-7. A third coordination mode (component II) was identified at pH 8.0, and simulation of the superhyperfine resonances indicated a 3N1O coordination sphere involving nitrogen ligation by His6, His13, and His14. No differences were observed upon (17)O-labeling of the phenolic oxygen of Tyr10, confirming it is not a key oxygen ligand in the physiological pH range. Hyperfine sublevel correlation (HYSCORE) spectroscopy, in conjunction with site-specific (15)N-labeling, provided additional support for the common role of His6 in components Ia and Ib, and for the assignment of a {O, N(epsilon)(H6), N(epsilon)(H13), N(epsilon)(H14)} coordination sphere to component II. HYSCORE studies of a peptide analogue with selective (13)C-labeling of Asp1 revealed (13)C cross-peaks characteristic of equatorial coordination by the carboxylate oxygen of Asp1 in component Ia/b coordination. The direct resolution of Cu(2+) ligand interactions, together with the key finding that component I is composed of two distinct coordination modes, provides valuable insight into a range of conflicting ligand assignments and highlights the complexity of Cu(2+)/Abeta interactions.

  9. Protein expression changes induced in a malignant melanoma cell line by the curcumin analogue compound D6

    International Nuclear Information System (INIS)

    Pisano, Marina; Palomba, Antonio; Tanca, Alessandro; Pagnozzi, Daniela; Uzzau, Sergio; Addis, Maria Filippa; Dettori, Maria Antonietta; Fabbri, Davide; Palmieri, Giuseppe; Rozzo, Carla

    2016-01-01

    We have previously demonstrated that the hydroxylated biphenyl compound D6 (3E,3′E)-4,4′-(5,5′,6,6′-tetramethoxy-[1,1′-biphenyl]-3,3′-diyl)bis (but-3-en-2-one), a structural analogue of curcumin, exerts a strong antitumor activity on melanoma cells both in vitro and in vivo. Although the mechanism of action of D6 is yet to be clarified, this compound is thought to inhibit cancer cell growth by arresting the cell cycle in G2/M phase, and to induce apoptosis through the mitochondrial intrinsic pathway. To investigate the changes in protein expression induced by exposure of melanoma cells to D6, a differential proteomic study was carried out on D6-treated and untreated primary melanoma LB24Dagi cells. Proteins were fractionated by SDS-PAGE and subjected to in gel digestion. The peptide mixtures were analyzed by liquid chromatography coupled with tandem mass spectrometry. Proteins were identified and quantified using database search and spectral counting. Proteomic data were finally uploaded into the Ingenuity Pathway Analysis software to find significantly modulated networks and pathways. Analysis of the differentially expressed protein profiles revealed the activation of a strong cellular stress response, with overexpression of several HSPs and stimulation of ubiquitin-proteasome pathways. These were accompanied by a decrease of protein synthesis, evidenced by downregulation of proteins involved in mRNA processing and translation. These findings are consistent with our previous results on gene expression profiling in melanoma cells treated with D6. Our findings confirm that the curcumin analogue D6 triggers a strong stress response in melanoma cells, turning down majority of cell functions and finally driving cells to apoptosis. The online version of this article (doi:10.1186/s12885-016-2362-6) contains supplementary material, which is available to authorized users

  10. Interaction between amyloid beta peptide and an aggregation blocker peptide mimicking islet amyloid polypeptide.

    Directory of Open Access Journals (Sweden)

    Nasrollah Rezaei-Ghaleh

    Full Text Available Assembly of amyloid-beta peptide (Aβ into cytotoxic oligomeric and fibrillar aggregates is believed to be a major pathologic event in Alzheimer's disease (AD and interfering with Aβ aggregation is an important strategy in the development of novel therapeutic approaches. Prior studies have shown that the double N-methylated analogue of islet amyloid polypeptide (IAPP IAPP-GI, which is a conformationally constrained IAPP analogue mimicking a non-amyloidogenic IAPP conformation, is capable of blocking cytotoxic self-assembly of Aβ. Here we investigate the interaction of IAPP-GI with Aβ40 and Aβ42 using NMR spectroscopy. The most pronounced NMR chemical shift changes were observed for residues 13-20, while residues 7-9, 15-16 as well as the C-terminal half of Aβ--that is both regions of the Aβ sequence that are converted into β-strands in amyloid fibrils--were less accessible to solvent in the presence of IAPP-GI. At the same time, interaction of IAPP-GI with Aβ resulted in a concentration-dependent co-aggregation of Aβ and IAPP-GI that was enhanced for the more aggregation prone Aβ42 peptide. On the basis of the reduced toxicity of the Aβ peptide in the presence of IAPP-GI, our data are consistent with the suggestion that IAPP-GI redirects Aβ into nontoxic "off-pathway" aggregates.

  11. Different binding motifs of the celiac disease-associated HLA molecules DQ2.5, DQ2.2, and DQ7.5 revealed by relative quantitative proteomics of endogenous peptide repertoires

    DEFF Research Database (Denmark)

    Bergseng, Elin; Dørum, Siri; Arntzen, Magnus Ø.

    2014-01-01

    Celiac disease is caused by intolerance to cereal gluten proteins, and HLA-DQ molecules are involved in the disease pathogenesis by presentation of gluten peptides to CD4+ T cells. The α- or β-chain sharing HLA molecules DQ2.5, DQ2.2, and DQ7.5 display different risks for the disease...... established binding motifs. The binding motif of DQ2.2 was strikingly different from that of DQ2.5 with position P3 being a major anchor having a preference for threonine and serine. This is notable as three recently identified epitopes of gluten recognized by T cells of DQ2.2 celiac patients harbor serine...... at position P3. This study demonstrates that relative quantitative comparison of endogenous peptides sampled from our protein metabolism by HLA molecules provides clues to understand HLA association with disease....

  12. Synthesis and biological evaluation of febrifugine analogues.

    Science.gov (United States)

    Mai, Huong Doan Thi; Thanh, Giang Vo; Tran, Van Hieu; Vu, Van Nam; Vu, Van Loi; Le, Cong Vinh; Nguyen, Thuy Linh; Phi, Thi Dao; Truong, Bich Ngan; Chau, Van Minh; Pham, Van Cuong

    2014-12-01

    A series of febrifugine analogues were designed and synthesized. Antimalarial activity evaluation of the synthetic compounds indicated that these derivatives had a strong inhibition against both chloroquine-sensitive and -resistant Plasmodium falciparum parasites. Many of them were found to be more active than febrifugine hydrochloride. The tested analogues had also a significant cytotoxicity against four cancer cell lines (KB, MCF7, LU1 and HepG2). Among the synthetic analogues, two compounds 17b and 17h displayed a moderate cytotoxicity while they exhibited a remarkable antimalarial activity.

  13. Antimicrobial Activity of Resveratrol Analogues

    Directory of Open Access Journals (Sweden)

    Malik Chalal

    2014-06-01

    Full Text Available Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew. Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold. The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups and antimicrobial activity.

  14. 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...

  15. A non-covalent peptide-based carrier for in vivo delivery of DNA mimics

    OpenAIRE

    Morris, May C.; Gros, Edwige; Aldrian-Herrada, Gudrun; Choob, Michael; Archdeacon, John; Heitz, Frederic; Divita, Gilles

    2007-01-01

    The dramatic acceleration in identification of new nucleic-acid-based therapeutic molecules has provided new perspectives in pharmaceutical research. However, their development is limited by their poor cellular uptake and inefficient trafficking. Here we describe a short amphipathic peptide, Pep-3, that combines a tryptophan/phenylalanine domain with a lysine/arginine-rich hydrophilic motif. Pep-3 forms stable nano-size complexes with peptide-nucleic acid analogues and promotes their efficien...

  16. Overlapping but distinct specificities of anti-liver-kidney microsome antibodies in autoimmune hepatitis type II and hepatitis C revealed by recombinant native CYP2D6 and novel peptide epitopes

    Science.gov (United States)

    Klein, R; Zanger, U M; Berg, T; Hopf, U; Berg, P A

    1999-01-01

    Anti-liver-kidney microsome antibodies (anti-LKM) occur in autoimmune hepatitis (AIH) type II and in a subset of patients with hepatitis C. Anti-LKM1 in AIH are directed against cytochrome P4502D6 (CYP2D6), but conflicting data exist concerning the specificity of anti-LKM in hepatitis C. The aim of this study was to evaluate binding specificities of anti-LKM antibodies in both diseases using novel test antigens as well as their inhibitory capacity on CYP2D6 enzyme activity. Sera from 22 patients with AIH type II and 17 patients with hepatitis C being anti-LKM-positive in the immunofluorescence test were investigated for binding to native recombinant CYP2D6 and liver microsomes by ELISA and immunoblotting, and to synthetic peptides covering the region 254–339 (254–273, 257–269, 270–294, 291–310, 307–324, 321–339, 373–389) as well as the novel peptide 196–218 by ELISA. Furthermore, all sera were tested for inhibition of CYP2D6-dependent bufuralol 1′-hydroxylase activity. Twenty of the 22 AIH type II sera (91%) and nine of the 17 hepatitis C sera (53%) were positive for CYP2D6 by ELISA and/or immunoblotting. The previously described major peptide epitope comprising CYP2D6 amino acids 257–269 was recognized by 16 of the 22 AIH sera but by only one hepatitis C serum. A further epitope, 196–218, could be defined for the first time as another immunodominant epitope for AIH because it was recognized by 15 of the 22 AIH (68%) but only three of the 17 hepatitis C sera (18%). With the exception of the peptide 254–273, the other peptides showed no significant reactivity. Analysing the inhibitory properties of anti-LKM antibodies it emerged that 95% of AIH sera and 88% of hepatitis C sera inhibited enzyme function. These data indicate that anti-LKM antibodies in AIH and hepatitis C react with CYP2D6, as shown by their inhibitory activity, and that besides the known epitope 257–269 a further immunodominant epitope exists on CYP2D6 which is recognized

  17. Amphetamine-Like Analogues in Diabetes: Speeding towards Ketogenesis

    Directory of Open Access Journals (Sweden)

    Natalia M. Branis

    2015-01-01

    Full Text Available Obesity is common in patients with type 1 and type 2 diabetes. Amphetamine-like analogues comprise the most popular class of weight loss medications. We present a case of a 34-year-old African American female with a history of type 1 diabetes, dyslipidemia, and obesity who developed diabetic ketoacidosis (DKA after starting Diethylpropion for the purpose of weight loss. Shortly after starting Diethylpropion, she developed nausea, vomiting, and periumbilical pain. Blood work revealed glucose of 718 mg/dL, pH 7.32 (7.35–7.45, bicarbonate 16 mmol/L (22–29 mmol/L, and anion gap 19 mmol/L (8–16 mmol/L. Urine analysis demonstrated large amount of ketones. She was hospitalized and successfully treated for DKA. Diethylpropion was discontinued. Amphetamine-like analogues administration leads to norepinephrine release from the lateral hypothalamus which results in the appetite suppression. Peripheral norepinephrine concentration rises as well. Norepinephrine stimulates adipocyte lipolysis and thereby increases nonesterified fatty acids (NEFA availability. It promotes β-oxidation of NEFA to ketone bodies while decreasing metabolic clearance rate of ketones. In the setting of acute insulin deficiency these effects are augmented. Females are more sensitive to norepinephrine effects compared to males. In conclusion, amphetamine-like analogues lead to a release of norepinephrine which can result in a clinically significant ketosis, especially in the setting of insulin deficiency.

  18. Design and synthesis of biotin analogues reversibly binding with streptavidin.

    Science.gov (United States)

    Yamamoto, Tomohiro; Aoki, Kiyoshi; Sugiyama, Akira; Doi, Hirofumi; Kodama, Tatsuhiko; Shimizu, Yohei; Kanai, Motomu

    2015-04-01

    Two new biotin analogues, biotin carbonate 5 and biotin carbamate 6, have been synthesized. These molecules were designed to reversibly bind with streptavidin by replacing the hydrogen-bond donor NH group(s) of biotin's cyclic urea moiety with oxygen. Biotin carbonate 5 was synthesized from L-arabinose (7), which furnishes the desired stereochemistry at the 3,4-cis-dihydroxy groups, in 11% overall yield (over 10 steps). Synthesis of biotin carbamate 6 was accomplished from L-cysteine-derived chiral aldehyde 33 in 11% overall yield (over 7 steps). Surface plasmon resonance analysis of water-soluble biotin carbonate analogue 46 and biotin carbamate analogue 47 revealed that KD values of these compounds for binding to streptavidin were 6.7×10(-6)  M and 1.7×10(-10)  M, respectively. These values were remarkably greater than that of biotin (KD =10(-15)  M), and thus indicate the importance of the nitrogen atoms for the strong binding between biotin and streptavidin. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Effect of GAPDH-derived antimicrobial peptides on sensitive yeasts cells: membrane permeability, intracellular pH and H+-influx/-efflux rates.

    Science.gov (United States)

    Branco, Patrícia; Albergaria, Helena; Arneborg, Nils; Prista, Catarina

    2018-05-01

    Saccharomyces cerevisiae secretes antimicrobial peptides (AMPs) derived from glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which induce the death of several non-Saccharomyces yeasts. Previously, we demonstrated that the naturally secreted GAPDH-derived AMPs (i.e. saccharomycin) caused a loss of culturability and decreased the intracellular pH (pHi) of Hanseniaspora guilliermondii cells. In this study, we show that chemically synthesised analogues of saccharomycin also induce a pHi drop and loss of culturability in H. guilliermondii, although to a lesser extent than saccharomycin. To assess the underlying causes of the pHi drop, we evaluated the membrane permeability to H+ cations of H. guilliermondii cells, after being exposed to saccharomycin or its synthetic analogues. Results showed that the H+-efflux decreased by 75.6% and the H+-influx increased by 66.5% in cells exposed to saccharomycin at pH 3.5. Since H+-efflux via H+-ATPase is energy dependent, reduced glucose consumption would decrease ATP production and consequently H+-ATPase activity. However, glucose uptake rates were not affected, suggesting that the AMPs rather than affecting glucose transporters may affect directly the plasma membrane H+-ATPase or increase ATP leakage due to cell membrane disturbance. Thus, our study revealed that both saccharomycin and its synthetic analogues induced cell death of H. guilliermondii by increasing the proton influx and inhibiting the proton efflux.

  20. Rethinking of the criteria for natural analogue study. A case of Tono natural analogue study

    International Nuclear Information System (INIS)

    Yoshida, Hidekazu

    1996-01-01

    Natural analogue regarding long-term performance of the geological disposal system for radioactive waste isolation is essentially the study of geochemical process which has been evolved in geological environment. All geochemical studies, however, will not be nominated as natural analogue studies. It is, therefore, important to be clear the criteria for natural analogue study with the view of analogy by following three categories, (1) Conceptual model development, (2) Data provision and (3) Model testing, for the concept of geological disposal and safety assessment model. Rethinking of the criteria for natural analogue study through the case of Tono Natural Analogue Study, and the usefulness of natural analogue study for the safety assessment of geological disposal system in Japan have been presented in this paper. (author)

  1. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  2. 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.

  3. 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....

  4. 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....

  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 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....

  7. 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.

  8. International video project on natural analogues

    International Nuclear Information System (INIS)

    Guentensperger, Marcel

    1993-01-01

    A natural analogue can be defined as a natural process which has occurred in the past and is studied in order to test predictions about the future evolution of similar processes. In recent years, natural analogues have been used increasingly to test the mathematical models required for repository performance assessment. Analogues are, however, also of considerable use in public relations as they allow many of the principles involved in demonstrating repository safety to be illustrated in a clear manner using natural systems with which man is familiar. The international Natural Analogue Working Group (NAWG), organised under the auspices of the CEC, has recognised that such PR applications are of considerable importance and should be supported from a technical level. At the NAWG meeting in Pitlochry, Scotland (June 1990), it was recommended that the possibilities for making a video film on this topic be investigated and Nagra was requested to take the lead role in setting up such a project

  9. Natural analogues and radionuclide transport model validation

    International Nuclear Information System (INIS)

    Lever, D.A.

    1987-08-01

    In this paper, some possible roles for natural analogues are discussed from the point of view of those involved with the development of mathematical models for radionuclide transport and with the use of these models in repository safety assessments. The characteristic features of a safety assessment are outlined in order to address the questions of where natural analogues can be used to improve our understanding of the processes involved and where they can assist in validating the models that are used. Natural analogues have the potential to provide useful information about some critical processes, especially long-term chemical processes and migration rates. There is likely to be considerable uncertainty and ambiguity associated with the interpretation of natural analogues, and thus it is their general features which should be emphasized, and models with appropriate levels of sophistication should be used. Experience gained in modelling the Koongarra uranium deposit in northern Australia is drawn upon. (author)

  10. The Planetary Terrestrial Analogues Library (PTAL)

    Science.gov (United States)

    Werner, S. C.; Dypvik, H.; Poulet, F.; Rull Perez, F.; Bibring, J.-P.; Bultel, B.; Casanova Roque, C.; Carter, J.; Cousin, A.; Guzman, A.; Hamm, V.; Hellevang, H.; Lantz, C.; Lopez-Reyes, G.; Manrique, J. A.; Maurice, S.; Medina Garcia, J.; Navarro, R.; Negro, J. I.; Neumann, E. R.; Pilorget, C.; Riu, L.; Sætre, C.; Sansano Caramazana, A.; Sanz Arranz, A.; Sobron Grañón, F.; Veneranda, M.; Viennet, J.-C.; PTAL Team

    2018-04-01

    The Planetary Terrestrial Analogues Library project aims to build and exploit a spectral data base for the characterisation of the mineralogical and geological evolution of terrestrial planets and small solar system bodies.

  11. Pharmaceutical design and pharmacological characterization of Tc99m [99mTc] labelled somatostatin and gastrin analogues

    International Nuclear Information System (INIS)

    Guggenberg, E. von

    2004-10-01

    The development of regulatory peptide analogues radiolabelled with 99m Tc is of great interest for nuclear medicine applications, as 99m Tc shows very favourable imaging characteristics, such as low radiation burden to the patient, optimal image quality in SPECT, one-day-acquisition-protocol, availability on demand and cost effectiveness. In this work the principles of pharmaceutical design and preclinical pharmacological characterization of regulatory peptide analogues labelled with 99m Tc with possible application in tumour diagnosis are described. [ 99m Tc-EDDA-HYNIC0,Tyr3]octreotide ( 99m Tc-EDDA-HYNIC-TOC) is a promising new radiopharmaceutical with the potential to replace [ 111 In-DTPA0]octreotide in receptor scintigraphy of somatostatin receptor-positive tumours. Radiolabelling at high labelling yields and high specific activities could be obtained applying a coligand exchange labelling approach from tricine for EDDA under optimized conditions of pH, EDDA and stannous ion concentration. The resulting complex was characterized via HPLC, receptor binding and LC-MS. For the development of a freeze-dried kit formulation with long shelf-life, high stability of the final preparation and retained biological activity, the addition of bulking agent, the pH of the freeze-drying solution and the content of stannous chloride were of major importance. Different methods of radiochemical purity testing were evaluated to guarantee high quality of the preparation in a clinical setting, forming the basis for a further clinical evaluation of this promising new radiopharmaceutical. Radiolabelling of [D-Glu1]minigastrin (MG) with 99m Tc was studied applying two different labelling approaches. HYNIC-MG could be labelled using tricine and EDDA as coligands; and (Nalpha-His)Ac-MG was used as tridentate ligand for the 99m Tc carbonyl core. Stability experiments by HPLC analysis in PBS, serum, histidine- and cysteine-solutions as well as rat liver and kidney homogenates, receptor

  12. Glucagon-like peptide-1 (GLP-1) receptor agonism or DPP-4 inhibition does not accelerate neoplasia in carcinogen treated mice

    DEFF Research Database (Denmark)

    Kissow, Hannelouise; Hartmann, Bolette; Holst, Jens Juul

    2012-01-01

    Glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are secreted in parallel from the intestinal endocrine cells after nutrient intake. GLP-1 is an incretin hormone and analogues are available for the treatment of type 2 diabetes mellitus (T2DM). GLP-2 is an intestinal growth horm...

  13. A distributive peptide cyclase processes multiple microviridin core peptides within a single polypeptide substrate.

    Science.gov (United States)

    Zhang, Yi; Li, Kunhua; Yang, Guang; McBride, Joshua L; Bruner, Steven D; Ding, Yousong

    2018-05-03

    Ribosomally synthesized and post-translationally modified peptides (RiPPs) are an important family of natural products. Their biosynthesis follows a common scheme in which the leader peptide of a precursor peptide guides the modifications of a single core peptide. Here we describe biochemical studies of the processing of multiple core peptides within a precursor peptide, rare in RiPP biosynthesis. In a cyanobacterial microviridin pathway, an ATP-grasp ligase, AMdnC, installs up to two macrolactones on each of the three core peptides within AMdnA. The enzyme catalysis occurs in a distributive fashion and follows an unstrict N-to-C overall directionality, but a strict order in macrolactonizing each core peptide. Furthermore, AMdnC is catalytically versatile to process unnatural substrates carrying one to four core peptides, and kinetic studies provide insights into its catalytic properties. Collectively, our results reveal a distinct biosynthetic logic of RiPPs, opening up the possibility of modular production via synthetic biology approaches.

  14. Hyperthermic responses to central injections of some peptide and non-peptide opioids in the guinea-pig

    Science.gov (United States)

    Kandasamy, S. B.; Williams, B. A.

    1983-01-01

    The intracerebroventricular administration of prototype nonpeptide opioid receptor (mu, kappa, and sigma) agonists, morphine, ketocyclazocine, and N-allyl normetazocine and an agonist at both kappa and sigma receptors, pentazocine, was found to induce hyperthermia in guinea pigs. The similar administration of peptide opioids like beta endorphin, methionine endkephalin, leucine endkephaline, and several of their synthetic analogues was also found to cause hyperthermia. Only the liver-like transport system of the three anion transport systems (iodide, hippurate, and liver-like) present in the choroid plexus was determined to be important to the central inactivation of beta-endorphin and two synthetic analogues. Prostaglandins and norepinephrine (NE) as well as cAMP were not involved in peptide and nonpeptide opioid-induced hyperthermia. Naloxone-sensitive receptors were found to be involved in the induction of hyperthermia by morphine and beta-endorphin, while hyperthermic responses to ketocyclazocine, N-allyl normetazocine, pentazocine, Met-enkephalin, Leu-enkephalin, and two of the synthetic analogues were not antagonized by nalozone. The lack of antagonism of naloxone on pyrogen, arachidonic acid, PGE2, dibutyryl cAMP, and NE-induced hyperthermia shows that endogenous opioid peptides are not likely to be central mediators of the hyperthermia induced by these agents.

  15. Novel short antibacterial and antifungal peptides with low cytotoxicity: Efficacy and action mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiaobao; Zhou, Chuncai; Li, Peng [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 Singapore (Singapore); Xu, Weixin [School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore (Singapore); Cao, Ye; Ling, Hua; Ning Chen, Wei; Ming Li, Chang; Xu, Rong [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 Singapore (Singapore); Lamrani, Mouad [Menicon Co., Ltd. Immeuble Espace Cordeliers, 2, rue President Carnot, 69002 Lyon (France); Mu, Yuguang, E-mail: ygmu@ntu.edu.sg [School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore (Singapore); Leong, Susanna Su Jan [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 Singapore (Singapore); Wook Chang, Matthew, E-mail: matthewchang@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 Singapore (Singapore); Chan-Park, Mary B., E-mail: mbechan@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 Singapore (Singapore)

    2010-07-30

    Research highlights: {yields} Short antimicrobial peptides with nine and eleven residues were developed. {yields} These peptides show strong bactericidal activity against clinically important bacterial and fungal pathogens. {yields} These peptides exhibit high stability in the presence of salts, and low cytotoxicity. {yields} These peptides exert their action by disrupting membrane lipids. -- Abstract: Short antimicrobial peptides with nine and eleven residues were developed against several clinically important bacterial and fungal pathogens (specifically Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Fusarium solani). Twelve analogues of previously reported peptides BP76 (KKLFKKILKFL) and Pac-525 (KWRRWVRWI) were designed, synthesized, and tested for their antimicrobial activities. Two of our eleven amino acid peptides, P11-5 (GKLFKKILKIL) and P11-6 (KKLIKKILKIL), have very low MICs of 3.1-12.5 {mu}g ml{sup -1} against all five pathogens. The MICs of these two peptides against S. aureus, C. albicans and F. solani are four to ten times lower than the corresponding MICs of the reference peptide BP76. P9-4 (KWRRWIRWL), our newly designed nine-amino acid analogue, also has particularly low MICs of 3.1-6.2 {mu}g ml{sup -1} against four of the tested pathogens; these MICs are two to eight times lower than those reported for Pac-525 (6.2-50 {mu}g ml{sup -1}).These new peptides (P11-5, P11-6 and P9-4) also exhibit improved stability in the presence of salts, and have low cytotoxicity as shown by the hemolysis and MTT assays. From the results of field-emission scanning electron microscopy, membrane depolarization and dye-leakage assays, we propose that these peptides exert their action by disrupting membrane lipids. Molecular dynamics simulation studies confirm that P11-6 peptide maintains relatively stable helical structure and exerts more perturbation action on the order of acyl tail of lipid bilayer.

  16. Effect of sequence and stereochemistry reversal on p53 peptide mimicry.

    Directory of Open Access Journals (Sweden)

    Alessio Atzori

    Full Text Available Peptidomimetics effective in modulating protein-protein interactions and resistant to proteolysis have potential in therapeutic applications. An appealing yet underperforming peptidomimetic strategy is to employ D-amino acids and reversed sequences to mimic a lead peptide conformation, either separately or as the combined retro-inverso peptide. In this work, we examine the conformations of inverse, reverse and retro-inverso peptides of p53(15-29 using implicit solvent molecular dynamics simulation and circular dichroism spectroscopy. In order to obtain converged ensembles for the peptides, we find enhanced sampling is required via the replica exchange molecular dynamics method. From these replica exchange simulations, the D-peptide analogues of p53(15-29 result in a predominantly left-handed helical conformation. When the parent sequence is reversed sequence as either the L-peptide and D-peptide, these peptides display a greater helical propensity, feature reflected by NMR and CD studies in TFE/water solvent. The simulations also indicate that, while approximately similar orientations of the side-chains are possible by the peptide analogues, their ability to mimic the parent peptide is severely compromised by backbone orientation (for D-amino acids and side-chain orientation (for reversed sequences. A retro-inverso peptide is disadvantaged as a mimic in both aspects, and further chemical modification is required to enable this concept to be used fruitfully in peptidomimetic design. The replica exchange molecular simulation approach adopted here, with its ability to provide detailed conformational insights into modified peptides, has potential as a tool to guide structure-based design of new improved peptidomimetics.

  17. Radiolabelled peptides and nanoparticles for specific molecular targeting in oncology

    International Nuclear Information System (INIS)

    Helbok, A.

    2011-01-01

    - derivatization. Targeting approaches aiming at regulatory peptide receptors were performed with liposomal NP, liposomes and micelles, derivatized with the Somatostatin (SST) analogue Tyrosine-3-octreotide (TOC) as a proof of concept. Influence of the different size of liposomes vs. micelles and the different amount of TOC - peptide load in the NP - formulation were studied and directly compared to targeting properties of a free molecule. Results showed specific binding to tumour cells in vitro (rat pancreatic tumour cells (AR42J)), however, moderate in vivo tumour uptake in AR42J - xenografted nude mice indicates that further improvement of these NP - constructs is needed. Micelles and liposomes revealed comparable pharmacokinetics and targeting properties. Eventually this work demonstrates the attempt to develop a radioligand for targeting CCK-2 tumour receptors over - expressed in i.e. medullary thyroid carcinomas. It was envisaged to improve the targeting properties and lower kidney uptake by truncating the peptide and replacement of two amino - acids, respectively. Results demonstrated efficient targeting of the shortened peptide sequence, however, replacement of amino - acids failed to improve targeting properties. Reduction of kidney uptake was achieved, however, at the expense of the stability of the peptides. In summary, the experiments and considerations presented in this thesis can be regarded as a basis for the development of multifunctional NP for sustained and targeted delivery of different agents targeting, diagnosing and / or treating diseases such as cancer. Such multifunctional NP can eventually be administered for simultaneous in vivo detection and visualisation of malignant tumour cells via specific targeting moieties, treatment of cancer cells and) monitoring the treatment effects. (author)

  18. Peptide stabilized amphotericin B nanodisks

    Science.gov (United States)

    Tufteland, Megan; Pesavento, Joseph B.; Bermingham, Rachelle L.; Hoeprich, Paul D.; Ryan, Robert O.

    2007-01-01

    Nanometer scale apolipoprotein A-I stabilized phospholipid disk complexes (nanodisks; ND) have been formulated with the polyene antibiotic amphotericin B (AMB). The present studies were designed to evaluate if a peptide can substitute for the function of the apolipoprotein component of ND with respect to particle formation and stability. An 18-residue synthetic amphipathic α-helical peptide, termed 4F (Ac-D-W-F-K-A-F-Y-D-K-V-A-E-K-F-K-E-A-F-NH2), solubilized vesicles comprised of egg phosphatidylcholine (egg PC), dipentadecanoyl PC or dimyristoylphosphatidylcholine (DMPC) at rates greater than or equal to solubilization rates observed with human apolipoprotein A-I (apoA-I; 243 amino acids). Characterization studies revealed that interaction with DMPC induced a near doubling of 4F tryptophan fluorescence emission quantum yield (excitation 280 nm) and a ~7 nm blue shift in emission wavelength maximum. Inclusion of AMB in the vesicle substrate resulted in formation of 4F AMB-ND. Spectra of AMB containing particles revealed the antibiotic is a highly effective quencher of 4F tryptophan fluorescence emission, giving rise to a Ksv = 7.7 × 104. Negative stain electron microscopy revealed that AMB-ND prepared with 4F possessed a disk shaped morphology similar to ND prepared without AMB or prepared with apoA-I. In yeast and pathogenic fungi growth inhibition assays, 4F AMB-ND was as effective as apoA-I AMB-ND. The data indicate that AMB-ND generated using an amphipathic peptide in lieu of apoA-I form a discrete population of particles that possess potent biological activity. Given their intrinsic versatility, peptides may be preferred for scale up and clinical application of AMB-ND. PMID:17293004

  19. Comparative biodistribution of 12 {sup 111}In-labelled gastrin/CCK2 receptor-targeting peptides

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Joosten, Lieke; Eek, Annemarie; Roosenburg, Susan; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Peitl, Petra Kolenc [University Medical Centre Ljubljana, Department of Nuclear Medicine, Ljubljana (Slovenia); Maina, Theodosia [National Center for Scientific Research Demokritos, Molecular Radiopharmacy, Institute of Radioisotopes-Radiodiagnostic Products, Athens (Greece); Maecke, Helmut [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany); Aloj, Luigi [Fondazione ' ' G. Pascale' ' , Department of Nuclear Medicine, Istituto Nazionale Tumouri, Naples (Italy); Guggenberg, Elisabeth von [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Sosabowski, Jane K. [Queen Mary, University of London, Centre for Molecular Oncology and Imaging, Institute of Cancer, Barts and The London School of Medicine and Dentistry, London (United Kingdom); Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Reubi, Jean-Claude [University of Berne, Institute of Pathology, Berne (Switzerland)

    2011-08-15

    Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed and some have been tested in patients. Here we aimed to compare the in vivo tumour targeting properties of 12 {sup 111}In-labelled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-conjugated gastrin/CCK2 receptor-binding peptides. Two CCK8-based peptides and ten gastrin-based peptide analogues were tested. All peptides were conjugated with DOTA and labelled with {sup 111}In. Biodistribution studies were performed in mice with subcutaneous CCK2/gastrin receptor-expressing tumours and with receptor-negative tumours contralaterally. Biodistribution was studied by counting dissected tissues at 1 and 4 h after injection. Both the CCK analogues displayed relatively low tumour uptake (approximately 2.5%ID/g) as compared to minigastrin analogues. Two linear minigastrin peptides (MG0 and sargastrin) displayed moderate tumour uptake at both 1 and 4 h after injection, but also very high kidney uptake (both higher than 48%ID/g). The linear MG11, lacking the penta-Glu sequence, showed lower tumour uptake and also low kidney uptake. Varying the N-terminal Glu residues in the minigastrin analogues led to improved tumour targeting properties, with PP-F11 displaying the optimal biodistribution. Besides the monomeric linear peptides, a cyclized peptide and a divalent peptide were tested. Based on these studies, optimal peptides for peptide receptor radionuclide targeting of CCK2/gastrin receptor-expressing tumours were the linear minigastrin analogue with six D-Glu residues (PP-F11), the divalent analogue MGD5 and the cyclic peptide cyclo-MG1. These peptides combined high tumour uptake with low kidney retention, and may

  20. Cold, Gas-Phase UV and IR Spectroscopy of Protonated Leucine Enkephalin and its Analogues

    Science.gov (United States)

    Burke, Nicole L.; Redwine, James; Dean, Jacob C.; McLuckey, Scott A.; Zwier, Timothy S.

    2014-06-01

    The conformational preferences of peptide backbones and the resulting hydrogen bonding patterns provide critical biochemical information regarding the structure-function relationship of peptides and proteins. The spectroscopic study of cryogenically-cooled peptide ions in a mass spectrometer probes these H-bonding arrangements and provides information regarding the influence of a charge site. Leucine enkephalin, a biologically active endogenous opiod peptide, has been extensively studied as a model peptide in mass spectrometry. This talk will present a study of the UV and IR spectroscopy of protonated leucine enkephalin [YGGFL+H]+ and two of its analogues: the sodiated [YGGFL+Na]+ and C-terminally methyl esterified [YGGFL-OMe+H]+ forms. All experiments were performed in a recently completed multi-stage mass spectrometer outfitted with a cryocooled ion trap. Ions are generated via nano-electrospray ionization and the analyte of interest is isolated in a linear ion trap. The analyte ions are trapped in a 22-pole ion trap held at 5 K by a closed cycle helium cryostat and interrogated via UV and IR lasers. Photofragments are trapped and isolated in a second LIT and mass analyzed. Double-resonance UV and IR methods were used to assign the conformation of [YGGFL+H]+, using the NH/OH stretch, Amide I, and Amide II regions of the infrared spectrum. The assigned structure contains a single backbone conformation at vibrational/rotational temperatures of 10 K held together with multiple H-bonds that self-solvate the NH3+ site. A "proton wire" between the N and C termini reinforces the H-bonding activity of the COO-H group to the F-L peptide bond, whose cleavage results in formation of the b4 ion, which is a prevalent, low-energy fragmentation pathway for [YGGFL+H]+. The reinforced H-bonding network in conjunction with the mobile proton theory may help explain the prevalence of the b4 pathway. In order to elucidate structural changes caused by modifying this H-bonding activity

  1. Between Analogue and Digital Diagrams

    Directory of Open Access Journals (Sweden)

    Zoltan Bun

    2012-10-01

    Full Text Available This essay is about the interstitial. About how the diagram, as a method of design, has lead fromthe analogue deconstruction of the eighties to the digital processes of the turn of the millennium.Specifically, the main topic of the text is the interpretation and the critique of folding (as a diagramin the beginning of the nineties. It is necessary then to unfold its relationship with immediatelypreceding and following architectural trends, that is to say we have to look both backwards andforwards by about a decade. The question is the context of folding, the exchange of the analogueworld for the digital. To understand the process it is easier to investigate from the fields of artand culture, rather than from the intentionally perplicated1 thoughts of Gilles Deleuze. Both fieldsare relevant here because they can similarly be used as the yardstick against which the era itselfit measured. The cultural scene of the eighties and nineties, including performing arts, movies,literature and philosophy, is a wide milieu of architecture. Architecture responds parallel to itsera; it reacts to it, and changes with it and within it. Architecture is a medium, it has always beena medium, yet the relations are transformed. That’s not to say that technical progress, for exampleusing CAD-software and CNC-s, has led to the digital thinking of certain movements ofarchitecture, (it is at most an indirect tool. But the ‘up-to-dateness’ of the discipline, however,a kind of non-servile reading of an ‘applied culture’ or ‘used philosophy’2 could be the key.(We might recall here, parenthetically, the fortunes of the artistic in contemporary mass society.The proliferation of museums, the magnification of the figure of the artist, the existence of amassive consumption of printed and televised artistic images, the widespread appetite for informationabout the arts, all reflect, of course, an increasingly leisured society, but also relateprecisely to the fact

  2. Reaction analogues in the radiation-induced deamination and dephosphorylation of bio-organic molecules 2: Oxygenated solutions

    International Nuclear Information System (INIS)

    Garrison, W.M.

    1988-02-01

    The OH-induced deamination and dephosphorylation of simple peptides and phosphate esters in oxygenated solutions involve the fomation and subsequent degradation of the perodyl radicals RCONHC(/dot O/)R 2 and /bigcirc P/ OC(/dot O/ 2 )R 2 respectively. Reaction analogues in the degradation of peroxyl and alkoxyl radicals in these two systems are evaluated with reference to the OH-induced main-chain cleavage of protein and DNA. 25 refs

  3. Highly potent metallopeptide analogues of luteinizing hormone-releasing hormone.

    Science.gov (United States)

    Bajusz, S; Janaky, T; Csernus, V J; Bokser, L; Fekete, M; Srkalovic, G; Redding, T W; Schally, A V

    1989-08-01

    Metal complexes related to the cytotoxic complexes cisplatin [cis-diamminedichloroplatinum(II)] and transbis(salicylaldoximato)copper(II) were incorporated into suitably modified luteinizing hormone-releasing hormone (LH-RH) analogues containing D-lysine at position 6. Some of the metallopeptides thus obtained proved to be highly active LH-RH agonists or antagonists. For instance, SB-40, a PtCl2-containing metallopeptide in which platinum is coordinated to an N epsilon-(DL-2,3-diaminopropionyl)-D-lysine residue [D-Lys(DL-A2pr] at position 6, showed 50 times higher LH-releasing potency than the native hormone. SB-95, [Ac-D-Nal(2)1,D-Phe(pCl)2, D-Pal(3)2, Arg5,D-Lys[DL-A2pr(Sal2Cu)]6,D-Ala10]LH-RH, where Nal(2) is 3-(2-naphthyl)alanine, Pal(3) is 3-(3-pyridyl)alanine, and copper(II) is coordinated to the salicylideneimino moieties resulting from condensation of salicylaldehyde with D-Lys(DL-A2pr)6, caused 100% inhibition of ovulation at a dose of 3 micrograms in rats. Most metallopeptide analogues of LH-RH showed high affinities for the membrane receptors of rat pituitary and human breast cancer cells. Some of these metallopeptides had cytotoxic activity against human breast cancer and prostate cancer cell lines in vitro (this will be the subject of a separate paper on cytotoxicity evaluation). Such cytostatic metallopeptides could be envisioned as targeted chemotherapeutic agents in cancers that contain receptors for LH-RH-like peptides.

  4. Comparison of Two Kinds of 64Cu Labelled Octreotide Analogues

    Directory of Open Access Journals (Sweden)

    HAN Zhen-yi1;LIANG Ji-xin1;HU Ji2;LUO Hong-yi1;QING Jing2;CHEN Yu-qing2;LI Guang2;LI Hong-yu1,2

    2016-10-01

    Full Text Available Octreotide analogues DOTA-TOC and DOTA-TATE were labeled with 64Cu. The influences of the ratio of peptide mass to 64Cu activity, pH value, temperature and reaction time on labeling yield were investigated. The optimum labeling was determined. In vitro stability tests in saline and 10% bovine serum had been carried out. Biodistribution of the two radiolabelled compounds in normal mice and Micro PET imaging in nude mice bearing U87MG tumor had been evaluated. The results showed that the labeling yields of 64Cu-DOTA-TOC and 64Cu-DOTA-TATE were higher than 95%. Two kinds of octreotide analogues labeled with 64Cu were quite stable in saline and decomposed slowly in 10% bovine serum at 37 ℃. Biodistribution results in normal mice showed that two 64Cu labelled tracers had similar profiles. Both of the compounds washed out from the blood quickly. High uptake of radioactivity in liver and kidneys indicated the tracers were excreted via both hepatobiliary system and renal system. At the same time, compared to 64Cu-DOTA-TOC, higher radioactivity accumulation of 64Cu-DOTA-TATE in liver and kidneys was observed. Micro PET images of U87MG tumor-bearing nude mice with 64Cu-DOTA-TOC and 64Cu-DOTA-TATE showed the tumors very clearly. The radioactivity uptake of 64Cu-DOTA-TATE in tumor was higher than that of 64Cu-DOTA-TOC. This work has paved the way for further preclinical and clinical application of 64Cu-DOTA-TOC and 64Cu-DOTA-TATE as PET tumor imaging agents.

  5. Modifications outside the proteinase binding loop in Cucurbita maxima trypsin inhibitor III (CMTI-III) analogues change the binding energy with bovine beta-trypsin.

    Science.gov (United States)

    Jaśkiewicz, A; Lis, K; Rózycki, J; Kupryszewski, G; Rolka, K; Ragnarsson, U; Zbyryt, T; Wilusz, T

    1998-10-02

    Five 26-peptide analogues of the trypsin inhibitor [Pro18]CMTI-III containing Leu or Tyr in position 7 and Val or Tyr in position 27: 1 (Leu7, Tyr27), 2 (Tyr7, Val27), 3 (Tyr7, Tyr27), 4 (Leu7, Val27) and 5 (Leu7, Ala18, Tyr27) were synthesized by the solid-phase method. Analogues 1-4 displayed Ka with bovine beta-trypsin of the same order of magnitude as the wild CMTI-III inhibitor, whereas for analogue 5, this value was lower by about 3 orders of magnitude. This indicated that for the analogues with Pro (but not with Ala) in position 18, the side-chain interactions between positions 7 and 27 did not play a critical role for the stabilization of the active structure. In addition, these results also suggest that Tyr7 is involved in an additional aromatic interaction with position 41 of the enzyme.

  6. Stabilised 111In-labelled DTPA- and DOTA-conjugated neurotensin analogues for imaging and therapy of exocrine pancreatic cancer

    International Nuclear Information System (INIS)

    Visser, M. de; Krenning, E.P.; Jong, M. de; Janssen, P.J.J.M.; Srinivasan, A.; Reubi, J.C.; Waser, B.; Erion, J.L.; Schmidt, M.A.

    2003-01-01

    Neurotensin (NT) receptors are overexpressed in exocrine pancreatic cancer and Ewing's sarcoma. The potential utility of native NT in cancer diagnosis and therapy is, however, limited by its rapid degradation in vivo. Therefore, NT analogues were synthesised with modified lysine and arginine derivatives to enhance stability and coupled either to DTPA, to enable high specific activity labelling with indium-111 for imaging, or to DOTA, to enable high specific activity labelling with β-emitting radionuclides, such as lutetium-177 and yttrium-90. Based on serum stability (4 h incubation at 37 C in human serum) and receptor binding affinity, the five most promising analogues were selected and further evaluated in in vitro internalisation studies in human colorectal adenocarcinoma HT29 cells, which overexpress NT receptors. All five NT analogues bound with high affinity to NT receptors on human exocrine pancreatic tumour sections. The analogues could be labelled with 111 In to a high specific activity. The 111 In-labelled compounds were found to be very stable in serum. Incubation of HT29 cells with the 111 In-labelled analogues at 37 C showed rapid receptor-mediated uptake and internalisation. The most promising analogue, peptide 2530 [DTPA-(Pip)Gly-Pro-(PipAm)Gly-Arg-Pro-Tyr-tBuGly-Leu-OH] was further tested in vivo in a biodistribution study using HT29 tumour-bearing nude mice. The results of this study showed low percentages of injected dose per gram tissue of this 111 In-labelled 2530 analogue in receptor-negative organs like blood, spleen, pancreas, liver, muscle and femur. Good uptake was found in the receptor-positive HT29 tumour and high uptake was present in the kidneys. Co-injection of excess unlabelled NT significantly reduced tumour uptake, showing that tumour uptake is a receptor-mediated process. With their enhanced stability, maintained high receptor affinity and rapid receptor-mediated internalisation, the 111 In-labelled DTPA- and DOTA-conjugated NT

  7. A cocoa peptide protects Caenorhabditis elegans from oxidative stress and β-amyloid peptide toxicity.

    Directory of Open Access Journals (Sweden)

    Patricia Martorell

    Full Text Available BACKGROUND: Cocoa and cocoa-based products contain different compounds with beneficial properties for human health. Polyphenols are the most frequently studied, and display antioxidant properties. Moreover, protein content is a very interesting source of antioxidant bioactive peptides, which can be used therapeutically for the prevention of age-related diseases. METHODOLOGY/PRINCIPAL FINDINGS: A bioactive peptide, 13L (DNYDNSAGKWWVT, was obtained from a hydrolyzed cocoa by-product by chromatography. The in vitro inhibition of prolyl endopeptidase (PEP was used as screening method to select the suitable fraction for peptide identification. Functional analysis of 13L peptide was achieved using the transgenic Caenorhabditis elegans strain CL4176 expressing the human Aβ₁₋₄₂ peptide as a pre-clinical in vivo model for Alzheimer's disease. Among the peptides isolated, peptide 13L (1 µg/mL showed the highest antioxidant activity (P≤0.001 in the wild-type strain (N2. Furthermore, 13L produced a significant delay in body paralysis in strain CL4176, especially in the 24-47 h period after Aβ₁₋₄₂ peptide induction (P≤0.0001. This observation is in accordance with the reduction of Aβ deposits in CL4176 by western blot. Finally, transcriptomic analysis in wild-type nematodes treated with 13L revealed modulation of the proteosomal and synaptic functions as the main metabolic targets of the peptide. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the cocoa 13L peptide has antioxidant activity and may reduce Aβ deposition in a C. elegans model of Alzheimer's disease; and therefore has a putative therapeutic potential for prevention of age-related diseases. Further studies in murine models and humans will be essential to analyze the effectiveness of the 13L peptide in higher animals.

  8. Novel heparan sulfate-binding peptides for blocking herpesvirus entry.

    Directory of Open Access Journals (Sweden)

    Pranay Dogra

    Full Text Available Human cytomegalovirus (HCMV infection can lead to congenital hearing loss and mental retardation. Upon immune suppression, reactivation of latent HCMV or primary infection increases morbidity in cancer, transplantation, and late stage AIDS patients. Current treatments include nucleoside analogues, which have significant toxicities limiting their usefulness. In this study we screened a panel of synthetic heparin-binding peptides for their ability to prevent CMV infection in vitro. A peptide designated, p5+14 exhibited ~ 90% reduction in murine CMV (MCMV infection. Because negatively charged, cell-surface heparan sulfate proteoglycans (HSPGs, serve as the attachment receptor during the adsorption phase of the CMV infection cycle, we hypothesized that p5+14 effectively competes for CMV adsorption to the cell surface resulting in the reduction in infection. Positively charged Lys residues were required for peptide binding to cell-surface HSPGs and reducing viral infection. We show that this inhibition was not due to a direct neutralizing effect on the virus itself and that the peptide blocked adsorption of the virus. The peptide also inhibited infection of other herpesviruses: HCMV and herpes simplex virus 1 and 2 in vitro, demonstrating it has broad-spectrum antiviral activity. Therefore, this peptide may offer an adjunct therapy for the treatment of herpes viral infections and other viruses that use HSPGs for entry.

  9. Insulin analogues with improved absorption characteristics.

    Science.gov (United States)

    Brange, J; Hansen, J F; Langkjaer, L; Markussen, J; Ribel, U; Sørensen, A R

    1992-01-01

    The insulin preparations available today are not ideal for therapy as s.c. injection does not provide a physiological insulin profile. With the aim to improve the absorption properties recombinant DNA technology has been utilized to design novel insulin molecules with changed physico-chemical characteristics and hence altered subcutaneous absorption kinetics. Soluble, long-acting human insulin analogues in which the isoelectric point has been increased from 5.4 to approx. 7 are absorbed very slowly, providing a more constant basal insulin delivery with lower day-to-day variation than present protracted preparations. In addition they have better storage stability. Rapid-acting human insulin analogues with largely reduced self-association are absorbed substantially faster from subcutaneous tissue than current regular insulin and thus are better suited for bolus injection. The absorption kinetics of these analogues have been able to explain the mechanism behind the dose effect on insulin absorption rate.

  10. Synthesis and anticancer evaluation of spermatinamine analogues

    KAUST Repository

    Moosa, Basem

    2016-02-04

    Spermatinamine was isolated from an Australian marine sponge, Pseudoceratina sp. as an inhibitor of isoprenylcystiene carboxyl methyltransferase (Icmt), an attractive and novel anticancer target. Herein, we report the synthesis of spermatinamine analogues and their cytotoxic evaluation against three human cancer cell lines i.e. cervix adenocarcinoma (HeLa), breast adenocarcinoma (MCF-7), and prostate carcinoma (DU145). Analogues 12, 14 and 15 were found to be the most potent against one or more cell lines with the IC50 values in the range of 5 - 10 μM. The obtained results suggested that longer polyamine linker along with aromatic oxime substitution provided the most potent analogue compounds against cancer cell lines.

  11. The Suzuki–Miyaura Cross-Coupling as a Versatile Tool for Peptide Diversification and Cyclization

    Directory of Open Access Journals (Sweden)

    Tom Willemse

    2017-02-01

    Full Text Available The (site-selective derivatization of amino acids and peptides represents an attractive field with potential applications in the establishment of structure–activity relationships and labeling of bioactive compounds. In this respect, bioorthogonal cross-coupling reactions provide valuable means for ready access to peptide analogues with diversified structure and function. Due to the complex and chiral nature of peptides, mild reaction conditions are preferred; hence, a suitable cross-coupling reaction is required for the chemical modification of these challenging substrates. The Suzuki reaction, involving organoboron species, is appropriate given the stability and environmentally benign nature of these reactants and their amenability to be applied in (partial aqueous reaction conditions, an expected requirement upon the derivatization of peptides. Concerning the halogenated reaction partner, residues bearing halogen moieties can either be introduced directly as halogenated amino acids during solid-phase peptide synthesis (SPPS or genetically encoded into larger proteins. A reversed approach building in boron in the peptidic backbone is also possible. Furthermore, based on this complementarity, cyclic peptides can be prepared by halogenation, and borylation of two amino acid side chains present within the same peptidic substrate. Here, the Suzuki–Miyaura reaction is a tool to induce the desired cyclization. In this review, we discuss diverse amino acid and peptide-based applications explored by means of this extremely versatile cross-coupling reaction. With the advent of peptide-based drugs, versatile bioorthogonal conversions on these substrates have become highly valuable.

  12. Peptide transport through the blood-brain barrier. Final report 1 Jul 87-31 Dec 90

    Energy Technology Data Exchange (ETDEWEB)

    Partridge, W.M.

    1991-01-15

    Most neuropeptides are incapable of entering the brain from blood owing to the presence of unique anatomical structures in the brain capillary wall, which makes up the blood-brain barrier (BBB). Such neuropeptides could be introduced into the bloodstream by intranasal insufflation and, thus, could have powerful medicinal properties (e.g., Beta-endorphin for the treatment of pain, vasopressin analogues for treatment of memory, ACTH analogues for treatment of post-traumatic epilepsy), should these peptides be capable of traversing the BBB. One such strategy for peptide delivery through the BBB is the development of chimeric peptides, which is the basis of the present contract. The production of chimeric peptides involves the covalent coupling of a nontransportable peptide (e.g., Beta-endorphin, vasopressin) to a transportable vector peptide (e.g., insulin, transferrin, cationized albumin, histone). The transportable peptide is capable of penetrating the BBB via receptor-mediated or absorptive-mediated transcytosis. Therefore, the introduction of chimeric peptides allows the nontransportable peptide to traverse the BBB via a physiologic piggy back mechanism.

  13. Peptides in melanoma therapy.

    Science.gov (United States)

    Mocellin, Simone

    2012-01-01

    Peptides derived from tumor associated antigens can be utilized to elicit a therapeutically effective immune response against melanoma in experimental models. However, patient vaccination with peptides - although it is often followed by the induction of melanoma- specific T lymphocytes - is rarely associated with tumor response of clinical relevance. In this review I summarize the principles of peptide design as well as the results so far obtained in the clinical setting while treating cutaneous melanoma by means of this active immunotherapy strategy. I also discuss some immunological and methodological issues that might be helpful for the successful development of peptide-based vaccines.

  14. Somatostatin analogues labelled with 99mTc

    International Nuclear Information System (INIS)

    Obenaus, E.; Crudo, J.; Edreira, M.; Viaggi, M.; De Castiglia, S.G.

    2001-01-01

    The aim of the present work was to study the biological and radiochemical behaviour of two somatostatin analogues, the RC-160 and Tyr3Octreotide(TOC) peptides when labelling with 99m Tc by two methods: direct and indirect using S-benzoyl- mercaptoacetyl triglycine (MAG-3) and hydrazinonicotinamide (HYNIC) as chelating agents. RC-160 was labelled with 125I (30% labelling yield) in order to examine its receptor specificity and to study the biodistribution in normal animals. A total binding of 30% and a non specific binding lower than 10% was obtained. On the other hand, the RC-160 was labelled with 99m Tc by a direct method (70% labelling yield), using sodium ascorbate and dithionite in order to reduce the peptide and 99m Tc, respectively. The synthesis of RC-160 with S-benzoyl MAG-3 and TOC with HYNIC, for labelling with 99m Tc are also described. The conjugates were prepared on a small scale and labelled with the radionuclide using tricine as co-ligands for HYNIC conjugates. Chromatographic studies were performed using HPLC system and radiochemical purities higher than 75% and 95% were obtained respectively. Biodistributions studies in normal Wistar rats were performed and results were correlated with chromatographic and protein binding properties. Lower lipophilicity of the labelled conjugates resulted in a higher renal excretion. HYNIC-TOC complex showed promising results when labelling with 99m Tc using tricine as co-ligand although higher stability should be found for ternary co-ligands compared to tricine. (author)

  15. Marine Peptides and Their Anti-Infective Activities

    OpenAIRE

    Kang, Hee Kyoung; Seo, Chang Ho; Park, Yoonkyung

    2015-01-01

    Marine bioresources are a valuable source of bioactive compounds with industrial and nutraceutical potential. Numerous clinical trials evaluating novel chemotherapeutic agents derived from marine sources have revealed novel mechanisms of action. Recently, marine-derived bioactive peptides have attracted attention owing to their numerous beneficial effects. Moreover, several studies have reported that marine peptides exhibit various anti-infective activities, such as antimicrobial, antifungal,...

  16. The use of chimeric vimentin citrullinated peptides for the diagnosis of rheumatoid arthritis.

    Science.gov (United States)

    Malakoutikhah, Morteza; Gómara, María J; Gómez-Puerta, José A; Sanmartí, Raimon; Haro, Isabel

    2011-11-10

    Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation and, in many cases, destruction of the joints. To prevent progressive and irreversible structural damage, early diagnosis of RA is of paramount importance. The present study addresses the search of new RA citrullinated antigens that could supplement or complement diagnostic/prognostic existing tests. With this aim, the epitope anticitrullinated vimentin antibody response was mapped using synthetic peptides. To improve the sensitivity/specificity balance, a vimentin peptide that was selected, and its cyclic analogue, were combined with fibrin- and filaggrin-related peptides to render chimeric peptides. Our findings highlight the putative application of these chimeric peptides for the design of RA diagnosis systems and imply that more than one serological test is required to classify RA patients based on the presence or absence of ACPAs. Each of the target molecules reported here (fibrin, vimentin, filaggrin) has a specific utility in the identification of a particular subset of RA patients.

  17. A new class of HIV-1 protease inhibitor: the crystallographic structure, inhibition and chemical synthesis of an aminimide peptide isostere.

    Science.gov (United States)

    Rutenber, E E; McPhee, F; Kaplan, A P; Gallion, S L; Hogan, J C; Craik, C S; Stroud, R M

    1996-09-01

    The essential role of HIV-1 protease (HIV-1 PR) in the viral life cycle makes it an attractive target for the development of substrate-based inhibitors that may find efficacy as anti-AIDS drugs. However, resistance has arisen to potent peptidomimetic drugs necessitating the further development of novel chemical backbones for diversity based chemistry focused on probing the active site for inhibitor interactions and binding modes that evade protease resistance. AQ148 is a potent inhibitor of HIV-1 PR and represents a new class of transition state analogues incorporating an aminimide peptide isostere. A 3-D crystallographic structure of AQ148, a tetrapeptide isostere, has been determined in complex with its target HIV-1 PR to a resolution of 2.5 A and used to evaluate the specific structural determinants of AQ148 potency and to correlate structure-activity relationships within the class of related compounds. AQ148 is a competitive inhibitor of HIV-1 PR with a Ki value of 137 nM. Twenty-nine derivatives have been synthesized and chemical modifications have been made at the P1, P2, P1', and P2' sites. The atomic resolution structure of AQ148 bound to HIV-1 PR reveals both an inhibitor binding mode that closely resembles that of other peptidomimetic inhibitors and specific protein/inhibitor interactions that correlate with structure-activity relationships. The structure provides the basis for the design, synthesis and evaluation of the next generation of hydroxyethyl aminimide inhibitors. The aminimide peptide isostere is a scaffold with favorable biological properties well suited to both the combinatorial methods of peptidomimesis and the rational design of potent and specific substrate-based analogues.

  18. Analogue alternative the electronic analogue computer in Britain and the USA, 1930-1975

    CERN Document Server

    Small, James S

    2013-01-01

    We are in the midst of a digital revolution - until recently, the majority of appliances used in everyday life have been developed with analogue technology. Now, either at home or out and about, we are surrounded by digital technology such as digital 'film', audio systems, computers and telephones. From the late 1940s until the 1970s, analogue technology was a genuine alternative to digital, and the two competing technologies ran parallel with each other. During this period, a community of engineers, scientists, academics and businessmen continued to develop and promote the analogue computer.

  19. The interaction of new piroxicam analogues with lipid bilayers--a calorimetric and fluorescence spectroscopic study.

    Science.gov (United States)

    Maniewska, Jadwiga; Szczęśniak-Sięga, Berenika; Poła, Andrzej; Sroda-Pomianek, Kamila; Malinka, Wiesław; Michalak, Krystyna

    2014-01-01

    The purpose of the present paper was to assess the ability of new piroxicam analogues to interact with the lipid bilayers. The results of calorimetric and fluorescence spectroscopic experiments of two new synthesized analogues of piroxicam, named PR17 and PR18 on the phase behavior of phospholipid bilayers and fluorescence quenching of fluorescent probes (Laurdan and Prodan), which molecular location within membranes is known with certainty, are shown in present work. The presented results revealed that, depending on the details of chemical structure, the studied compounds penetrated the lipid bilayers.

  20. QSAR Studies of 6-Amino Uracil Base Analogues: A Thymidine Phosphorylase Inhibitor in Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Surya Prakash B. N. Gupta

    2008-01-01

    Full Text Available A novel series of 6-amino uracil base analogue were synthesized. QSAR study was used to relate the selective nonsubstrate inhibitory activity of 6-amino uracil base analogue with various physicochemical descriptors. Stepwise multiple regression analysis was performed to find out the correlation between various physicochemical descriptors and biological activity of the compounds by using Openstat 2 version 6.5.1 and valstat statistical software. Out of the several equations developed, the best equation having the highest significance was selected for further study. The equation is able to explain 60% of total variance and are more than 95% significant as revealed by the F value.

  1. Insulin C-peptide test

    Science.gov (United States)

    C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin the body produces and insulin someone injects ...

  2. Strategies for the solid-phase diversification of poly-L-proline-type II peptide mimic scaffolds and peptide scaffolds through guanidinylation.

    Science.gov (United States)

    Flemer, Stevenson; Wurthmann, Alexander; Mamai, Ahmed; Madalengoitia, José S

    2008-10-03

    A strategy for the solid-phase diversification of PPII mimic scaffolds through guanidinylation is presented. The approach involves the synthesis N-Pmc-N'-alkyl thioureas as diversification reagents. Analogues of Fmoc-Orn(Mtt)-OH can be incorporated into a growing peptide chain on Wang resin. Side chain deprotection with 1% TFA/CH2Cl2 followed by EDCI-mediated reaction of N-Pmc-N'-alkyl thioureas with the side chain amine affords arginine analogues with modified guanidine head groups. The scope, limitations, and incidental chemistry are discussed.

  3. Migrastatin analogues inhibit canine mammary cancer cell migration and invasion.

    Directory of Open Access Journals (Sweden)

    Kinga Majchrzak

    Full Text Available BACKGROUND: Cancer spread to other organs is the main cause of death of oncological patients. Migration of cancer cells from a primary tumour is the crucial step in the complex process of metastasis, therefore blocking this process is currently the main treatment strategy. Metastasis inhibitors derived from natural products, such as, migrastatin, are very promising anticancer agents. Thus, the aim of our study was to investigate the effect of six migrastatin analogues (MGSTA-1 to 6 on migration and invasion of canine mammary adenocarcinoma cell lines isolated from primary tumours and their metastases to the lungs. Canine mammary tumours constitute a valuable tool for studying multiple aspect of human cancer. RESULTS: OUR RESULTS SHOWED THAT TWO OF SIX FULLY SYNTHETIC ANALOGUES OF MIGRASTATIN: MGSTA-5 and MGSTA-6 were potent inhibitors of canine mammary cancer cells migration and invasion. These data were obtained using the wound healing test, as well as trans-well migration and invasion assays. Furthermore, the treatment of cancer cells with the most effective compound (MGSTA-6 disturbed binding between filamentous F-actin and fascin1. Confocal microscopy analyses revealed that treatment with MGSTA-6 increased the presence of unbound fascin1 and reduced co-localization of F-actin and fascin1 in canine cancer cells. Most likely, actin filaments were not cross-linked by fascin1 and did not generate the typical filopodial architecture of actin filaments in response to the activity of MGSTA-6. Thus, administration of MGSTA-6 results in decreased formation of filopodia protrusions and stress fibres in canine mammary cancer cells, causing inhibition of cancer migration and invasion. CONCLUSION: Two synthetic migrastatin analogues (MGSTA-5 and MGSTA-6 were shown to be promising compounds for inhibition of cancer metastasis. They may have beneficial therapeutic effects in cancer therapy in dogs, especially in combination with other anticancer drugs

  4. Peptide Vaccines for Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Rory C. F. De Brito

    2018-05-01

    Full Text Available Due to an increase in the incidence of leishmaniases worldwide, the development of new strategies such as prophylactic vaccines to prevent infection and decrease the disease have become a high priority. Classic vaccines against leishmaniases were based on live or attenuated parasites or their subunits. Nevertheless, the use of whole parasite or their subunits for vaccine production has numerous disadvantages. Therefore, the use of Leishmania peptides to design more specific vaccines against leishmaniases seems promising. Moreover, peptides have several benefits in comparison with other kinds of antigens, for instance, good stability, absence of potentially damaging materials, antigen low complexity, and low-cost to scale up. By contrast, peptides are poor immunogenic alone, and they need to be delivered correctly. In this context, several approaches described in this review are useful to solve these drawbacks. Approaches, such as, peptides in combination with potent adjuvants, cellular vaccinations, adenovirus, polyepitopes, or DNA vaccines have been used to develop peptide-based vaccines. Recent advancements in peptide vaccine design, chimeric, or polypeptide vaccines and nanovaccines based on particles attached or formulated with antigenic components or peptides have been increasingly employed to drive a specific immune response. In this review, we briefly summarize the old, current, and future stands on peptide-based vaccines, describing the disadvantages and benefits associated with them. We also propose possible approaches to overcome the related weaknesses of synthetic vaccines and suggest future guidelines for their development.

  5. Peptide Vaccines for Leishmaniasis.

    Science.gov (United States)

    De Brito, Rory C F; Cardoso, Jamille M De O; Reis, Levi E S; Vieira, Joao F; Mathias, Fernando A S; Roatt, Bruno M; Aguiar-Soares, Rodrigo Dian D O; Ruiz, Jeronimo C; Resende, Daniela de M; Reis, Alexandre B

    2018-01-01

    Due to an increase in the incidence of leishmaniases worldwide, the development of new strategies such as prophylactic vaccines to prevent infection and decrease the disease have become a high priority. Classic vaccines against leishmaniases were based on live or attenuated parasites or their subunits. Nevertheless, the use of whole parasite or their subunits for vaccine production has numerous disadvantages. Therefore, the use of Leishmania peptides to design more specific vaccines against leishmaniases seems promising. Moreover, peptides have several benefits in comparison with other kinds of antigens, for instance, good stability, absence of potentially damaging materials, antigen low complexity, and low-cost to scale up. By contrast, peptides are poor immunogenic alone, and they need to be delivered correctly. In this context, several approaches described in this review are useful to solve these drawbacks. Approaches, such as, peptides in combination with potent adjuvants, cellular vaccinations, adenovirus, polyepitopes, or DNA vaccines have been used to develop peptide-based vaccines. Recent advancements in peptide vaccine design, chimeric, or polypeptide vaccines and nanovaccines based on particles attached or formulated with antigenic components or peptides have been increasingly employed to drive a specific immune response. In this review, we briefly summarize the old, current, and future stands on peptide-based vaccines, describing the disadvantages and benefits associated with them. We also propose possible approaches to overcome the related weaknesses of synthetic vaccines and suggest future guidelines for their development.

  6. 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...

  7. Prussian Blue Analogues of Reduced Dimensionality

    NARCIS (Netherlands)

    Gengler, Regis Y. N.; Toma, Luminita M.; Pardo, Emilio; Lloret, Francesc; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Gournis, Dimitrios; Rudolf, Petra

    2012-01-01

    Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While

  8. The Palmottu analogue project: overview for 1993

    International Nuclear Information System (INIS)

    Ruskeeniemi, T.; Blomqvist, R.; Suksi, J.; Niini, H.

    1994-01-01

    This article gives a summary of the activities carried out within the Palmottu analogue project in 1993. It consists of (1) an introductory part, followed by (2) a geological description of the site, and (3)an up-to-date summary of the results of the project. (orig.) (33 refs., 6 figs.)

  9. Somatostatin analogue scintigraphy and tuberculosis: case report

    International Nuclear Information System (INIS)

    Biancheri, I.; Rudenko, B.; Vautrin, P.; Raddoul, J.; Lamfichek, N.; Kantelip, B.; Mantion, G.

    2005-01-01

    Scintigraphy using a radiolabelled somatostatin analogue (111 In-pentetreotide) is useful in the detection of neuroendocrine tumors. But this radiopharmaceutical accumulates also in solid tumours or in inflammatory diseases such as granulomatosis. We present a case of 111 In-pentetreotide uptake in a tuberculous adenopathy. (author)

  10. Analogue computer display of accelerator beam optics

    International Nuclear Information System (INIS)

    Brand, K.

    1984-01-01

    Analogue computers have been used years ago by several authors for the design of magnetic beam handling systems. At Bochum a small analogue/hybrid computer was combined with a particular analogue expansion and logic control unit for beam transport work. This apparatus was very successful in the design and setup of the beam handling system of the tandem accelerator. The center of the stripper canal was the object point for the calculations, instead of the high energy acceleration tube a drift length was inserted into the program neglecting the weak focusing action of the tube. In the course of the installation of a second injector for heavy ions it became necessary to do better calculations. A simple method was found to represent accelerating sections on the computer and a particular way to simulate thin lenses was adopted. The analogue computer system proved its usefulness in the design and in studies of the characteristics of different accelerator installations over many years. The results of the calculations are in very good agreement with real accelerator data. The apparatus is the ideal tool to demonstrate beam optics to students and accelerator operators since the effect of a change of any of the parameters is immediately visible on the oscilloscope

  11. Scintigraphy with labelled analogues of the somatostatin

    International Nuclear Information System (INIS)

    Duet, M.; Ajzenberg, C.; Warnet, A.; Mundler, O.

    1998-01-01

    The receptors of the somatostatin have been localized in a big number of tumors, whom a great number are neuro-endocrine tumors. However, some tumors that have not this differentiation (breast cancer, lymphomas, cerebral tumors) possess them as well. Analogues of somatostatin, labelled with isotopes having a gamma emission, allow from now their detection in vivo. (N.C.)

  12. Ultrasound exfoliation of inorganic analogues of graphene

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Henych, Jiří; Slušná, Michaela; Ecorchard, Petra

    2014-01-01

    Roč. 9, APR (2014), s. 1-14 ISSN 1556-276X R&D Projects: GA ČR(CZ) GA14-05146S Institutional support: RVO:61388980 Keywords : Ultrasound * Exfoliation * Graphene inorganic analogues Subject RIV: CA - Inorganic Chemistry Impact factor: 2.779, year: 2014

  13. MARSI: metabolite analogues for rational strain improvement

    DEFF Research Database (Denmark)

    Cardoso, João G. R.; Zeidan, Ahmad A; Jensen, Kristian

    2018-01-01

    reactions in an organism can be used to predict effects of MAs on cellular phenotypes. Here, we present the Metabolite Analogues for Rational Strain Improvement (MARSI) framework. MARSI provides a rational approach to strain improvement by searching for metabolites as targets instead of genes or reactions...

  14. Redesigned Spider Peptide with Improved Antimicrobial and Anticancer Properties.

    Science.gov (United States)

    Troeira Henriques, Sónia; Lawrence, Nicole; Chaousis, Stephanie; Ravipati, Anjaneya S; Cheneval, Olivier; Benfield, Aurélie H; Elliott, Alysha G; Kavanagh, Angela Maria; Cooper, Matthew A; Chan, Lai Yue; Huang, Yen-Hua; Craik, David J

    2017-09-15

    Gomesin, a disulfide-rich antimicrobial peptide produced by the Brazilian spider Acanthoscurria gomesiana, has been shown to be potent against Gram-negative bacteria and to possess selective anticancer properties against melanoma cells. In a recent study, a backbone cyclized analogue of gomesin was shown to be as active but more stable than its native form. In the current study, we were interested in improving the antimicrobial properties of the cyclic gomesin, understanding its selectivity toward melanoma cells and elucidating its antimicrobial and anticancer mode of action. Rationally designed analogues of cyclic gomesin were examined for their antimicrobial potency, selectivity toward cancer cells, membrane-binding affinity, and ability to disrupt cell and model membranes. We improved the activity of cyclic gomesin by ∼10-fold against tested Gram-negative and Gram-positive bacteria without increasing toxicity to human red blood cells. In addition, we showed that gomesin and its analogues are more toxic toward melanoma and leukemia cells than toward red blood cells and act by selectively targeting and disrupting cancer cell membranes. Preference toward some cancer types is likely dependent on their different cell membrane properties. Our findings highlight the potential of peptides as antimicrobial and anticancer leads and the importance of selectively targeting cancer cell membranes for drug development.

  15. Synthesis of mutual azo prodrugs of anti-inflammatory agents and peptides facilitated by α-aminoisobutyric acid.

    Science.gov (United States)

    Kennedy, David A; Vembu, Nagarajan; Fronczek, Frank R; Devocelle, Marc

    2011-12-02

    Reported is the synthesis of azo mutual prodrugs of the nonsteroidal anti-inflammatory agents (NSAIDs) 4-aminophenylacetic acid (4-APAA) or 5-aminosalicylic acid (5-ASA) with peptides, including an antibiotic peptide temporin analogue modified at the amino terminal by an α-aminoisobutyric acid (Aib) residue. These prodrugs are designed for colonic delivery of two agents to treat infection and inflammation by the bacterial pathogen Clostridium difficile . © 2011 American Chemical Society

  16. Biological evaluation of 177Lu-labeled DOTA-Ala(SO3H)-Aminooctanoyl-Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-NH2 for gastrin-releasing peptide receptor-positive prostate tumor targeting

    International Nuclear Information System (INIS)

    Lim, Jae Cheong; Cho, Eun Ha; Kim, Jin Joo; Choi, Sang Mu; Lee, So young; Nam, Sung Soo; Park, Ul Jae; Park, Soo Hyun

    2015-01-01

    Bombesin binds with selectivity and high affinity to a Gastrin-releasing peptide receptor (GRPR), which is highly overexpressed in prostate cancer cells. The present study describes the in vitro and in vivo biological characteristics of DOTA-Ala(SO 3 H)-Aminooctanoyl-Gln-Trp-Ala-Val-N methyl Gly-His-Statine-Leu-NH 2 (DOTA-sBBNA), an antagonist analogue of bombesin peptide for the targeting of GRPR. DOTA-sBBNA was synthesized and labeled with 177 Lu as previously published. A saturation assay on PC-3 human prostate cancer cells revealed that the Kd value of the radiolabeled peptide was 1.88 nM with a maximum binding capacity (Bmax) of 289.3 fmol/10 6 cells. The radio-peptide slowly internalized, and 24.4 ± 0.5% of the total binding was internalized in 4 hr. Biodistribution studies were conducted in healthy and PC-3 xenografted balb/c mice, which showed high uptake and retention of tumor-associated radioactivity in PC-3 xenografted mice. The tumor-to-blood ratio was 126.02 ± 9.36 at 1.5 hr p.i., and was increased to 216.33 ± 61.58 at 24 hr p.i., which means that the radiolabeled peptide was highly accumulated in a tumor and rapidly cleared from the blood pool. The GRPR is also over-expressed in Korean prostate cancer patients. These results suggest that this 177 Lu-labeled peptide has promising characteristics for application in nuclear medicine, namely for the diagnosis and treatment of GRPR over-expressing prostate tumors

  17. Peptides for functionalization of InP semiconductors.

    Science.gov (United States)

    Estephan, Elias; Saab, Marie-belle; Larroque, Christian; Martin, Marta; Olsson, Fredrik; Lourdudoss, Sebastian; Gergely, Csilla

    2009-09-15

    The challenge is to achieve high specificity in molecular sensing by proper functionalization of micro/nano-structured semiconductors by peptides that reveal specific recognition for these structures. Here we report on surface modification of the InP semiconductors by adhesion peptides produced by the phage display technique. An M13 bacteriophage library has been used to screen 10(10) different peptides against the InP(001) and the InP(111) surfaces to finally isolate specific peptides for each orientation of the InP. MALDI-TOF/TOF mass spectrometry has been employed to study real affinity of the peptide towards the InP surfaces. The peptides serve for controlled placement of biotin onto InP to bind then streptavidin. Our Atomic Force Microscopy study revealed a total surface coverage of molecules when the InP surface was functionalized by its specific biotinylated peptide (YAIKGPSHFRPS). Finally, fluorescence microscopy has been employed to demonstrate the preferential attachment of the peptide onto a micro-patterned InP surface. Use of substrate specific peptides could present an alternative solution for the problems encountered in the actually existing sensing methods and molecular self-assembly due to the unwanted unspecific interactions.

  18. A novel lunar bed rest analogue.

    Science.gov (United States)

    Cavanagh, Peter R; Rice, Andrea J; Licata, Angelo A; Kuklis, Matthew M; Novotny, Sara C; Genc, Kerim O; Englehaupt, Ricki K; Hanson, Andrea M

    2013-11-01

    Humans will eventually return to the Moon and thus there is a need for a ground-based analogue to enable the study of physiological adaptations to lunar gravity. An important unanswered question is whether or not living on the lunar surface will provide adequate loading of the musculoskeletal system to prevent or attenuate the bone loss that is seen in microgravity. Previous simulations have involved tilting subjects to an approximately 9.5 degrees angle to achieve a lunar gravity component parallel to the long-axis of the body. However, subjects in these earlier simulations were not weight-bearing, and thus these protocols did not provide an analogue for load on the musculoskeletal system. We present a novel analogue which includes the capability to simulate standing and sitting in a lunar loading environment. A bed oriented at a 9.5 degrees angle was mounted on six linear bearings and was free to travel with one degree of freedom along rails. This allowed approximately 1/6 body weight loading of the feet during standing. "Lunar" sitting was also successfully simulated. A feasibility study demonstrated that the analogue was tolerated by subjects for 6 d of continuous bed rest and that the reaction forces at the feet during periods of standing were a reasonable simulation of lunar standing. During the 6 d, mean change in the volume of the quadriceps muscles was -1.6% +/- 1.7%. The proposed analogue would appear to be an acceptable simulation of lunar gravity and deserves further exploration in studies of longer duration.

  19. Atrial natriuretic peptides in plasma

    DEFF Research Database (Denmark)

    Goetze, Jens Peter; Hansen, Lasse H; Terzic, Dijana

    2014-01-01

    Measurement of cardiac natriuretic peptides in plasma has gained a diagnostic role in the assessment of heart failure. Plasma measurement is though hampered by the marked instability of the hormones, which has led to the development of analyses that target N-terminal fragments from the prohormone....... These fragments are stable in plasma and represent surrogate markers of the actual natriuretic hormone. Post-translational processing of the precursors, however, is revealing itself to be a complex event with new information still being reported on proteolysis, covalent modifications, and amino acid...

  20. Atrial natriuretic peptides in plasma

    DEFF Research Database (Denmark)

    Goetze, Jens P; Holst Hansen, Lasse; Terzic, Dijana

    2015-01-01

    Measurement of cardiac natriuretic peptides in plasma has gained a diagnostic role in the assessment of heart failure. Plasma measurement is though hampered by the marked instability of the hormones, which has led to the development of analyses that target N-terminal fragments from the prohormone....... These fragments are stable in plasma and represent surrogate markers of the actual natriuretic hormone. Post-translational processing of the precursors, however, is revealing itself to be a complex event with new information still being reported on proteolysis, covalent modifications, and amino acid...

  1. Cephalostatin analogues--synthesis and biological activity.

    Science.gov (United States)

    Flessner, Timo; Jautelat, Rolf; Scholz, Ulrich; Winterfeldt, Ekkehard

    2004-01-01

    Starting off in the early 90's the field of cephalostatin analogues has continually expanded over the last 10 years. First syntheses prepared symmetric analogues like 14b (119) and 26 (65), which were subsequently desymmetrized to provide analogues like beta-hydroxy ketone 31 (19). Importantly the straightforward approach provided already compounds with mu-molar potency and the same pattern of activity as cephalostatin 1 (1) (see Chapter 2.1). Chemically more demanding, two new methods for the directed synthesis of (bissteroidal) pyrazines were devised and subsequently applied to a wide variety of differently functionalized coupling partners. These new methods allowed for the synthesis of various analogues (Chapter 2.2.; and, last but not least, for the totals synthesis of several cephalostatin natural products; Chapter 1.). Functionalization and derivatization of the 12-position was performed (Chapter 2.1 and 3) and synthetic approaches to establish the D-ring double bond were successfully investigated (Chapter 3). [figure: see text] Dealing synthetically with the spiroketal moiety, novel oxidative opening procedures on monomeric delta 14, 15-steroids were devised as well as intensive studies regarding spiroketal synthesis and spiroketal rearrangements were conducted (Chapter 3.2. and 4.). Last but not least direct chemical modification of ritterazines and cephalostatins were studied, which provided a limited number of ritterazine analogues (Chapter 4.). All these synthetic activities towards analogues are summarized in Fig. 18. During this period of time the growing number of cephalostatins and ritterazines on the one hand and of analogues on the other hand provided several SAR trends, which can guide future analogue synthesis. The combined SAR findings are displayed in Fig. 19. So far it is apparent that: Additional methoxylations or hydroxylations in the steroidal A ring core structure (1-position) are slightly decreasing activity (compare cephalostatin 1 1 to

  2. Fingerprinting desmosine-containing elastin peptides

    DEFF Research Database (Denmark)

    Schräder, Christoph U; Heinz, Andrea; Majovsky, Petra

    2015-01-01

    , and DES-/IDES-containing peptides to determine characteristic product ions. It was found that all investigated compounds yielded the same product ion clusters at elevated collision energies. Elemental composition determination using the exact masses of these ions revealed molecular formulas of the type Cx...

  3. PEGylation of 99mTc-labeled bombesin analogues improves their pharmacokinetic properties

    International Nuclear Information System (INIS)

    Daepp, Simone; Garayoa, Elisa Garcia; Maes, Veronique; Brans, Luc; Tourwe, Dirk A.; Mueller, Cristina; Schibli, Roger

    2011-01-01

    Introduction: Radiolabeled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumors in which BN 2 /gastrin-releasing peptide (GRP) receptors are overexpressed. However, the low in vivo stability of BN conjugates may limit their clinical application. In an attempt to improve their pharmacokinetics and counteract their rapid enzymatic degradation, we prepared a series of polyethylene glycol (PEG)-ylated BN(7-14) analogues for radiolabeling with 99m Tc(CO) 3 and evaluated them in vitro and in vivo. Methods: Derivatization of a stabilized (N α His)Ac-BN(7-14)[Cha 13 ,Nle 14 ] analogue with linear PEG molecules of various sizes [5 kDa (PEG 5 ), 10 kDa (PEG 10 ) and 20 kDa (PEG 20 )] was performed by PEGylation of the ε-amino group of a β 3 hLys-βAla-βAla spacer between the stabilized BN sequence and the (N α His)Ac chelator. The analogues were then radiolabeled by employing the 99m Tc-tricarbonyl technique. Binding affinity and internalization/externalization studies were performed in vitro in human prostate carcinoma PC-3 cells. Stability was investigated in vitro in human plasma and in vivo in Balb/c mice. Finally, single photon emission computed tomography (SPECT)/X-ray computed tomography studies were performed in nude mice bearing PC-3 tumor xenografts. Results: PEGylation did not affect the binding affinity of BN analogues, as the binding affinity for BN 2 /GRP receptors remained high (K d 5 molecule showed the best pharmacokinetics in vivo, i.e., faster blood clearance and preferential renal excretion. The tumor uptake of the 99m Tc-PEG 5 -Lys-BN conjugate was slightly higher compared to that of the non-PEGylated analogue (3.91%±0.44% vs. 2.80%±0.28% injected dose per gram 1 h postinjection, p.i.). Tumor retention was also increased, resulting in a threefold higher amount of radioactivity in the tumor at 24 h p.i. Furthermore, decreased hepatobiliary excretion and increased tumor-to-nontarget ratios (tumor

  4. Gene transfer strategies for improving radiolabeled peptide imaging and therapy

    International Nuclear Information System (INIS)

    Rogers, B.E.; Buchsbaum, D.J.; Zinn, K.R.

    2000-01-01

    Utilization of molecular biology techniques offers attractive options in nuclear medicine for improving cancer imaging and therapy with radiolabeled peptides. Two of these options include utilization of phage-panning to identify novel tumor specific peptides or single chain antibodies and gene transfer techniques to increase the antibodies and gene transfer techniques to increase the number of antigen/receptor sites expressed on malignant cells. The group has focused on the latter approach for improving radiolabeled peptide imaging and therapy. The most widely used gene transfer vectors in clinical gene therapy trials include retrovirus, cationic lipids and adenovirus. It has been utilized adenovirus vectors for gene transfer because of their ability to accomplish efficient in vivo gene transfer. Adenovirus vectors encoding the genes for a variety of antigens/receptors (carcinoembryonic antigen, gastrin-releasing peptide receptor, somatostatin receptor subtype 2 (SSTr2) have all shown that their expression is increased on cancer cells both in vitro and in vivo following adenovirus infection. Of particular interest has been the adenovirus encoding for SSTr2 (AdCMVSSTr2). Various radioisotopes have been attached to somatostatin analogues for imaging and therapy of SSTr2-positive tumors both clinically and in animal models. The use of these analogues in combination with AdCMVSSTr2 is a promising approach for improving the detection sensitivity and therapeutic efficacy of these radiolabeled peptides against solid tumors. In addition, it has been proposed the use of SSTr2 as a marker for imaging the expression of another cancer therapeutic transgene (e.g. cytosine deaminase, thymidine kinase) encoded within the same vector. This would allow for non-invasive monitoring of gene delivery to tumor sites

  5. Insulin and C-peptide in human brain neurons (insulin/C-peptide/brain peptides/immunohistochemistry/radioimmunoassay)

    International Nuclear Information System (INIS)

    Dorn, A.; Bernstein, H.G.; Rinne, A.; Hahn, H.J.; Ziegler, M.

    1983-01-01

    The regional distribution and cellular localization of insulin and C-peptide immunoreactivities were studied in human cadaver brains using the indirect immunofluorescence method, the peroxidase-antiperoxidase technique, and radioimmunoassay. Products of the immune reactions to both polypeptides were observed in most nerve cells in all areas of the brain examined. Immunostaining was mainly restricted to the cell soma and proximal dendrites. Radioimmunoassay revealed that human brain contains insulin and C-peptide in concentrations much higher than the blood, the highest being in the hypothalamus. These findings support the hypothesis that the 'brain insulin' is - at least in part - produced in the CNS. (author)

  6. Nitenpyram analogues with 1,4-dihydropyridine fixed cis-configuration:synthesis,insecticidal activities and molecular docking studies

    Directory of Open Access Journals (Sweden)

    XUE Sijia

    2013-08-01

    Full Text Available A novel series of Nitenpyram analogues(Ia-Ij with 1,4-dihydropyridine fixed cis-configuration were designed and synthesized.Preliminary bioassays showed that most of them exhibited good insecticidal activities against Aphis medicagini and Brown rice planthopper at 500 mg/L and 100 mg/L.The analogue Ij afforded the best activity in vitro,that had 100% mortality at 4 mg/L against Brown rice planthopper and Aphis medicagin.In addition,the molecular docking simulations revealed that the structural uniqueness of these analogues may lead to a unique molecular recognition and binding mode,and the results explained the SARs observed in vitro, which shed light on the novel insecticidal mechanism of these novel nitenpyam analogues.

  7. Orlistat inhibition of intestinal lipase acutely increases appetite and attenuates postprandial glucagon-like peptide-1-(7-36)-amide-1, cholecystokinin, and peptide YY concentrations

    DEFF Research Database (Denmark)

    Ellrichmann, Mark; Kapelle, Mario; Ritter, Peter R

    2008-01-01

    of Orlistat or placebo. Gastric emptying, gallbladder volume and the plasma levels of CCK, PYY, GLP-1, and ghrelin were determined and appetite sensations were measured using visual analogue scales. RESULTS: Gastric emptying was accelerated by Orlistat administration (P emptying.......0001), whereas appetite and prospective food consumption increased (P gastric and gallbladder emptying and reduces...... whether Orlistat alters the secretion of glucagon-like peptide-1-(7-36)-amide (GLP-1), cholecystokinin (CCK), peptide YY (PYY), and ghrelin as well as postprandial appetite sensations. METHODS: Twenty-five healthy human volunteers were examined with a solid-liquid test meal after the oral administration...

  8. Diversity-oriented peptide stapling

    DEFF Research Database (Denmark)

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

    2017-01-01

    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...

  9. Boron hydride analogues of the fullerenes

    International Nuclear Information System (INIS)

    Quong, A.A.; Pederson, M.R.; Broughton, J.Q.

    1994-01-01

    The BH moiety is isoelectronic with C. We have studied the stability of the (BH) 60 analogue of the C 60 fullerene as well as the dual-structure (BH) 32 icosahedron, both of them being putative structures, by performing local-density-functional electronic calculations. To aid in our analysis, we have also studied other homologues of these systems. We find that the latter, i.e., the dual structure, is the more stable although the former is as stable as one of the latter's lower homologues. Boron hydrides, it seems, naturally form the dual structures used in algorithmic optimization of complex fullerene systems. Fully relaxed geometries are reported as well as electron affinities and effective Hubbard U parameters. These systems form very stable anions and we conclude that a search for BH analogues of the C 60 alkali-metal supeconductors might prove very fruitful

  10. Studies of natural analogues and geological systems

    International Nuclear Information System (INIS)

    Brandberg, F.; Grundfelt, B.; Hoeglund, L.; Skagius K.; Karlsson, F.; Smellie, J.

    1993-04-01

    This review has involved studies of natural analogues and natural geological systems leading to the identification and quantification of processes and features of importance to the performance and safety of repositories for radioactive waste. The features and processes selected for the study comprise general geochemical issues related to the performance of the near- and far-field, the performance and durability of construction materials and the effects of glaciation. For each of these areas a number of potentially important processes for repository performance have been described, and evidence for their existence, as well as quantification of parameters of models describing the processes have been sought from major natural analogue studies and site investigations. The review has aimed at covering a relatively broad range of issues at the expense of in-depth analysis. The quantitative data presented are in most cases compilations of data from the literature; in a few cases results of evaluations made within the current project are included

  11. The Brookhaven electron analogue, 1953--1957

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, M.

    1991-12-18

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary.

  12. Electromagnetic wave analogue of electronic diode

    OpenAIRE

    Shadrivov, Ilya V.; Powell, David A.; Kivshar, Yuri S.; Fedotov, Vassili A.; Zheludev, Nikolay I.

    2010-01-01

    An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of the polarization state rotation and is also a key component of optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by ...

  13. The Brookhaven electron analogue, 1953--1957

    International Nuclear Information System (INIS)

    Plotkin, M.

    1991-01-01

    The following topics are discussed on the Brookhaven electron analogue: L.J. Haworth and E.L. VanHorn letters; Original G.K. Green outline for report; General description; Parameter list; Mechanical Assembly; Alignment; Degaussing; Vacuum System; Injection System; The pulsed inflector; RF System; Ferrite Cavity; Pick-up electrodes and preamplifiers; Radio Frequency power amplifier; Lens supply; Controls and Power; and RF acceleration summary

  14. 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....

  15. Urodilatin. A renal natriuretic peptide

    International Nuclear Information System (INIS)

    Carstens, Jan

    1998-01-01

    Development and validation of a radioimmunoassay for endogenous URO in urine and synthetic URO in plasma is described. The first obstacle to overcome was to produce an antibody specific for URO. A polyclonal URO antibody with a cross-reactivity with the structural highly homologous atrial natriuretic peptide (ANP) was developed by immunization of rabbits with the whole URO(95-126). Purification of the polyclonal URO antiserum with CNBr-activated Sepharose affinity chromatography was a simple way of producing a URO-specific antibody without cross-reactivity with ANP analogues. A reliable 125 I-labelled URO tracer was made with the Iodo-Gen method. Prior to the assay, the urine samples were prepared by ethanol with a recovery of unlabelled URO between 80 - 100% and the plasma samples were Sep-Pak C 18 extracted with a recovery of about 50%. The radioimmunoassay is performed in 3 days, using polyethylene glycol for separation. The sensitivity of the assay was improved by sample preparation and concentration, reducing the amount of tracer and late addition, reducing the amount of antibody and increasing the incubation time and lowering the temperature of incubation. The infusion rate of 20 ng URO kg -1 min -1 was most potential and well tolerated in healthy subjects. The short-term natriuretic and diuretic effects were closely associated with a significant diminished sodium reabsorption in the distal nephron. Further studies are needed to exploit the therapeutical potential of URO, for example in patients with sodium-water retaining disorders. The therapeutical dose range will probably be narrow due to the blood pressure lowering effect of URO with infusion rates higher than 20-30 ng kg -1 min -1 . (EHS)

  16. 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

  17. Positron annihilation studies on nasicon analogues containing cation vacancies

    International Nuclear Information System (INIS)

    Sreeramalu, V.; Sreepad, H.R.; Chandrashekara, A.; Ravindrachary, V.; Gopal, S.

    1990-01-01

    Positron annihilation studies were carried out on the Nasicon analogue Na 2 (La, Al)Zr(PO 4 ) 3 compound for three different concentrations (2.2, 2.8 and 5.2 by wt.%) of ZrO 2 in the nutrient. Angular correlation study of annihilated photons reveals that the defect concentration is maximum for 2.8(wt.%) of ZrO 2 . Further, positron lifetime studies indicate that the positrons are trapped at cation vacancies. Application of a two state trapping model to this system made it possible to evaluate the lifetime of positrons in the Bloch state and of positrons trapped at cation vacancies. (author). 16 refs., 4 figs

  18. Glucagon-like peptide 1 and inhibitors of dipeptidyl peptidase IV in the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Deacon, Carolyn F

    2004-01-01

    Proof-of-concept for the efficacy of a glucagon-like peptide 1 (GLP-1)-based therapy of patients with type 2 diabetes was provided in 2002 by means of prolonged continuous subcutaneous infusion of native GLP-1. Since then, several long-acting analogues of GLP-1, as well as inhibitors of dipeptidyl...

  19. A safety and pharmacokinetic dosing study of glucagon-like peptide 2 in infants with intestinal failure

    DEFF Research Database (Denmark)

    Sigalet, David L; Brindle, Mary E; Boctor, Dana

    2017-01-01

    BACKGROUND & AIMS: Glucagon-like peptide 2 (GLP-2) analogues are approved for adults with intestinal failure (IF), but no studies have included infants. This study examined the pharmacokinetics (PK), safety, and nutritional effects of GLP-2 in infants with IF. METHODS: With parental consent (Health...

  20. High stability and biological activity of the copper(II) complexes of alloferon 1 analogues containing tryptophan.

    Science.gov (United States)

    Kadej, Agnieszka; Kuczer, Mariola; Czarniewska, Elżbieta; Urbański, Arkadiusz; Rosiński, Grzegorz; Kowalik-Jankowska, Teresa

    2016-10-01

    Copper(II) complex formation processes between the alloferon 1 (Allo1) (HGVSGHGQHGVHG) analogues where the tryptophan residue is introducing in the place His residue H1W, H6W, H9W and H12W have been studied by potentiometric, UV-visible, CD and EPR spectroscopic, and MS methods. For all analogues of alloferon 1 complex speciation have been obtained for a 1:1 metal-to-ligand molar ratio and 2:1 of H1W because of precipitation at higher (2:1, 3:1 and 4:1) ratios. At physiological pH7.4 and a 1:1 metal-to-ligand molar ratio the tryptophan analogues of alloferon 1 form the CuH -1 L and/or CuH -2 L complexes with the 4N binding mode. The introduction of tryptophan in place of histidine residues changes the distribution diagram of the complexes formed with the change of pH and their stability constants compared to the respective substituted alanine analogues of alloferon 1. The CuH -1 L, CuH -2 L and CuH -3 L complexes of the tryptophan analogues are more stable from 1 to 5 log units in comparison to those of the alanine analogues. This stabilization of the complexes may result from cation(Cu(II))-π and indole/imidazole ring interactions. The induction of apoptosis in vivo, in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH7.4 was studied. The biological results show that copper(II) ions in vivo did not cause any apparent apoptotic features. The most active were the H12W peptide and Cu(II)-H12W complex formed at pH7.4. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. NMR Insights into the Structure-Function Relationships in the Binding of Melanocortin Analogues to the MC1R Receptor.

    Science.gov (United States)

    Morais, Maurício; Zamora-Carreras, Héctor; Raposinho, Paula D; Oliveira, Maria Cristina; Pantoja-Uceda, David; Correia, João D G; Jiménez, M Angeles

    2017-07-15

    Linear and cyclic analogues of the α-melanocyte stimulating hormone (α-MSH) targeting the human melanocortin receptor 1 (MC1R) are of pharmacological interest for detecting and treating melanoma. The central sequence of α-MSH (His-Phe-Arg-Trp) has been identified as being essential for receptor binding. To deepen current knowledge on the molecular basis for α-MSH bioactivity, we aimed to understand the effect of cycle size on receptor binding. To that end, we synthesised two macrocyclic isomeric α-MSH analogues, c[NH-NO₂-C₆H₃-CO-His-DPhe-Arg-Trp-Lys]-Lys-NH₂ ( CycN-K6 ) and c[NH-NO₂-C₆H₃-CO-His-DPhe-Arg-Trp-Lys-Lys]-NH₂ ( CycN-K7 ). Their affinities to MC1R receptor were determined by competitive binding assays, and their structures were analysed by ¹H and 13 C NMR. These results were compared to those of the previously reported analogue c[S-NO₂-C₆H₃-CO-His-DPhe-Arg-Trp-Cys]-Lys-NH₂ ( CycS-C6 ). The MC1R binding affinity of the 22-membered macrocyclic peptide CycN-K6 (IC 50 = 155 ± 16 nM) is higher than that found for the 25-membered macrocyclic analogue CycN-K7 (IC 50 = 495 ± 101 nM), which, in turn, is higher than that observed for the 19-membered cyclic analogue CycS-C6 (IC 50 = 1770 ± 480 nM). NMR structural study indicated that macrocycle size leads to changes in the relative dispositions of the side chains, particularly in the packing of the Arg side chain relative to the aromatic rings. In contrast to the other analogues, the 22-membered cycle's side chains are favorably positioned for receptor interaction.

  2. Structural organization and spectroscopy of peptide-actinide(IV) complexes

    International Nuclear Information System (INIS)

    Dahou, S.

    2010-01-01

    The contamination of living organisms by actinide elements is at the origin of both radiological and chemical toxicity that may lead to severe dysfunction. Most of the data available on the actinide interaction with biological systems are macroscopic physiological measurements and are lacking a molecular description of the systems. Because of the intricacy of these systems, classical biochemical methods are difficult to implement. Our strategy consisted in designing simplified biomimetic peptides, and describing the corresponding intramolecular interactions with actinides. A carboxylic pentapeptide of the form DDPDD has been at the starting point of this work in order to further assess the influence of the peptide sequence on the topology of the complexes.To do so, various linear (Asp/Ala permutations, peptoids) and cyclic analogues have been synthesized. Furthermore, in order to include the hydroxamic function (with a high affinity for Fe(III)) in the peptide, both desferrioxamine and acetohydroxamic acid have been investigated. However because of difficulties in synthesis, we have not been able to test these peptides. Three actinide cations have been considered at oxidation state +IV (Th, Np, Pu) and compared to Fe(III), often considered as a biological surrogate of Pu(IV). The spatial arrangement of the peptide around the cation has been probed by spectrophotometry and X-ray Absorption Spectroscopy. The spectroscopic data and EXAFS data adjustment lead us to rationalize the topology of the complexes as a function of the peptide sequence: mix hydroxy polynuclear species for linear and cyclic peptides, mononuclear for the desferrioxamine complexes. Furthermore, significant differences have appeared between Fe(III) and actinide(IV), related to differences of reactivity in aqueous medium. (author)

  3. Peptide aldehyde inhibitors of bacterial peptide deformylases.

    Science.gov (United States)

    Durand, D J; Gordon Green, B; O'Connell, J F; Grant, S K

    1999-07-15

    Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity. Copyright 1999 Academic Press.

  4. Structure-function correlation of chloroquine and analogues as transgene expression enhancers in nonviral gene delivery.

    Science.gov (United States)

    Cheng, Jianjun; Zeidan, Ryan; Mishra, Swaroop; Liu, Aijie; Pun, Suzie H; Kulkarni, Rajan P; Jensen, Gregory S; Bellocq, Nathalie C; Davis, Mark E

    2006-11-02

    To understand how chloroquine (CQ) enhances transgene expression in polycation-based, nonviral gene delivery systems, a number of CQ analogues with variations in the aliphatic amino side chain or in the aromatic ring are synthesized and investigated. Our studies indicate that the aliphatic amino moiety of CQ is essential to provide increased gene expression. Further, the enhancements are more dramatically affected by changes to the aromatic ring and are positively correlated to the strength of intercalation between DNA and the CQ analogues. Quinacrine (QC), a CQ analogue with a fused acridinyl structure that can strongly intercalate DNA, enhances transfection similarly to CQ at a concentration 10 times lower, while N(4)-(4-pyridinyl)-N(1),N(1)-diethyl-1,4-pentanediamine (CP), a CQ analogue that has a weakly intercalating pyridinyl ring, shows no effect on gene expression. Subtle change on the 7-substituent of the chloroquine aromatic structure can also greatly affect the ability of the CQ analogues to enhance transgene expression. Transfection in the presence of N(4)-(7-trifluoromethyl-4-quinolinyl)-N(1),N(1)-diethyl-1,4-pentanediamin e (CQ7a) shows expression efficiency 10 times higher than in the presence of CQ at same concentration, while transfection in the presence of N(4)-(4-quinolinyl)-N(1),N(1)-diethyl-1,4-pentanediamine (CQ7b) does not reveal any enhancing effects on expression. Through a number of comparative studies with CQ and its analogues, we conclude that there are at least three mechanistic features of CQ that lead to the enhancement in gene expression: (i) pH buffering in endocytic vesicles, (ii) displacement of polycations from the nucleic acids in polyplexes, and (iii) alteration of the biophysical properties of the released nucleic acid.

  5. 99mTc labelled peptides for imaging peripheral receptors

    International Nuclear Information System (INIS)

    Gil, M.C.; Chandia, V.M.; Errazu, X.

    2001-01-01

    Radiolabelling of somatostatin analogues as RC-160 and TOC with 99m Tc, using direct and bifunctional chelating methods as well as quality control and evaluation methods, has been accomplished following the techniques and recommendation of the first and second RCMs. Synthesis of bifunctional chelating agents, such as Bz-MAG-3, is routinely produced in our laboratory. Synthesis of HYNIC and HYNIC-MAG-3 is in progress. Radioiodination of RC-160 using chloramine-T and iodogen methods were also studied in order to get experience with the different techniques used to evaluate the labelled peptides. (author)

  6. Proinsulin C-peptide interferes with insulin fibril formation

    International Nuclear Information System (INIS)

    Landreh, Michael; Stukenborg, Jan-Bernd; Willander, Hanna; Söder, Olle; Johansson, Jan; Jörnvall, Hans

    2012-01-01

    Highlights: ► Insulin and C-peptide can interact under insulin fibril forming conditions. ► C-peptide is incorporated into insulin aggregates and alters aggregation lag time. ► C-peptide changes insulin fibril morphology and affects backbone accessibility. ► C-peptide may be a regulator of fibril formation by β-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic β-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

  7. Antimicrobial peptide evolution in the Asiatic honey bee Apis cerana.

    Directory of Open Access Journals (Sweden)

    Peng Xu

    Full Text Available The Asiatic honeybee, Apis cerana Fabricius, is an important honeybee species in Asian countries. It is still found in the wild, but is also one of the few bee species that can be domesticated. It has acquired some genetic advantages and significantly different biological characteristics compared with other Apis species. However, it has been less studied, and over the past two decades, has become a threatened species in China. We designed primers for the sequences of the four antimicrobial peptide cDNA gene families (abaecin, defensin, apidaecin, and hymenoptaecin of the Western honeybee, Apis mellifera L. and identified all the antimicrobial peptide cDNA genes in the Asiatic honeybee for the first time. All the sequences were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR. In all, 29 different defensin cDNA genes coding 7 different defensin peptides, 11 different abaecin cDNA genes coding 2 different abaecin peptides, 13 different apidaecin cDNA genes coding 4 apidaecin peptides and 34 different hymenoptaecin cDNA genes coding 13 different hymenoptaecin peptides were cloned and identified from the Asiatic honeybee adult workers. Detailed comparison of these four antimicrobial peptide gene families with those of the Western honeybee revealed that there are many similarities in the quantity and amino acid components of peptides in the abaecin, defensin and apidaecin families, while many more hymenoptaecin peptides are found in the Asiatic honeybee than those in the Western honeybee (13 versus 1. The results indicated that the Asiatic honeybee adult generated more variable antimicrobial peptides, especially hymenoptaecin peptides than the Western honeybee when stimulated by pathogens or injury. This suggests that, compared to the Western honeybee that has a longer history of domestication, selection on the Asiatic honeybee has favored the generation of more variable antimicrobial peptides as protection against pathogens.

  8. Antimicrobial peptide evolution in the Asiatic honey bee Apis cerana.

    Science.gov (United States)

    Xu, Peng; Shi, Min; Chen, Xue-Xin

    2009-01-01

    The Asiatic honeybee, Apis cerana Fabricius, is an important honeybee species in Asian countries. It is still found in the wild, but is also one of the few bee species that can be domesticated. It has acquired some genetic advantages and significantly different biological characteristics compared with other Apis species. However, it has been less studied, and over the past two decades, has become a threatened species in China. We designed primers for the sequences of the four antimicrobial peptide cDNA gene families (abaecin, defensin, apidaecin, and hymenoptaecin) of the Western honeybee, Apis mellifera L. and identified all the antimicrobial peptide cDNA genes in the Asiatic honeybee for the first time. All the sequences were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). In all, 29 different defensin cDNA genes coding 7 different defensin peptides, 11 different abaecin cDNA genes coding 2 different abaecin peptides, 13 different apidaecin cDNA genes coding 4 apidaecin peptides and 34 different hymenoptaecin cDNA genes coding 13 different hymenoptaecin peptides were cloned and identified from the Asiatic honeybee adult workers. Detailed comparison of these four antimicrobial peptide gene families with those of the Western honeybee revealed that there are many similarities in the quantity and amino acid components of peptides in the abaecin, defensin and apidaecin families, while many more hymenoptaecin peptides are found in the Asiatic honeybee than those in the Western honeybee (13 versus 1). The results indicated that the Asiatic honeybee adult generated more variable antimicrobial peptides, especially hymenoptaecin peptides than the Western honeybee when stimulated by pathogens or injury. This suggests that, compared to the Western honeybee that has a longer history of domestication, selection on the Asiatic honeybee has favored the generation of more variable antimicrobial peptides as protection against pathogens.

  9. Proinsulin C-peptide interferes with insulin fibril formation

    Energy Technology Data Exchange (ETDEWEB)

    Landreh, Michael [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden); Stukenborg, Jan-Bernd [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Willander, Hanna [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Soeder, Olle [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Johansson, Jan [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-751 23 Uppsala (Sweden); Joernvall, Hans, E-mail: Hans.Jornvall@ki.se [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Insulin and C-peptide can interact under insulin fibril forming conditions. Black-Right-Pointing-Pointer C-peptide is incorporated into insulin aggregates and alters aggregation lag time. Black-Right-Pointing-Pointer C-peptide changes insulin fibril morphology and affects backbone accessibility. Black-Right-Pointing-Pointer C-peptide may be a regulator of fibril formation by {beta}-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic {beta}-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

  10. Time-dependent inhibitory effects of cGMP-analogues on thrombin-induced platelet-derived microparticles formation, platelet aggregation, and P-selectin expression

    International Nuclear Information System (INIS)

    Nygaard, Gyrid; Herfindal, Lars; Kopperud, Reidun; Aragay, Anna M.; Holmsen, Holm; Døskeland, Stein Ove; Kleppe, Rune; Selheim, Frode

    2014-01-01

    Highlights: • We investigated the impact of cyclic nucleotide analogues on platelet activation. • Different time dependence were found for inhibition of platelet activation. • Additive effect was found using PKA- and PKG-activating analogues. • Our results may explain some of the discrepancies reported for cNMP signalling. - Abstract: In platelets, nitric oxide (NO) activates cGMP/PKG signalling, whereas prostaglandins and adenosine signal through cAMP/PKA. Cyclic nucleotide signalling has been considered to play an inhibitory role in platelets. However, an early stimulatory effect of NO and cGMP-PKG signalling in low dose agonist-induced platelet activation have recently been suggested. Here, we investigated whether different experimental conditions could explain some of the discrepancy reported for platelet cGMP-PKG-signalling. We treated gel-filtered human platelets with cGMP and cAMP analogues, and used flow cytometric assays to detect low dose thrombin-induced formation of small platelet aggregates, single platelet disappearance (SPD), platelet-derived microparticles (PMP) and thrombin receptor agonist peptide (TRAP)-induced P-selectin expression. All four agonist-induced platelet activation phases were blocked when platelets were costimulated with the PKG activators 8-Br-PET-cGMP or 8-pCPT-cGMP and low-doses of thrombin or TRAP. However, extended incubation with 8-Br-PET-cGMP decreased its inhibition of TRAP-induced P-selectin expression in a time-dependent manner. This effect did not involve desensitisation of PKG or PKA activity, measured as site-specific VASP phosphorylation. Moreover, PKG activators in combination with the PKA activator Sp-5,6-DCL-cBIMPS revealed additive inhibitory effect on TRAP-induced P-selectin expression. Taken together, we found no evidence for a stimulatory role of cGMP/PKG in platelets activation and conclude rather that cGMP/PKG signalling has an important inhibitory function in human platelet activation

  11. Surface-enhanced Raman difference between bombesin and its modified analogues on the colloidal and electrochemically roughen silver surfaces.

    Science.gov (United States)

    Podstawka, Edyta; Ozaki, Yukihiro

    2008-10-01

    In this article, surface-enhanced Raman scattering (SERS) spectra of bombesin (BN) and its six modified analogues ([D-Phe(12)]BN, [Tyr(4)]BN, [Tyr(4),D-Phe(12)]BN, [D-Phe(12),Leu(14)]BN, [Leu(13)-(R)-Leu(14)]BN, and [Lys(3)]BN) on a colloidal silver surface are reported and compared with SERS spectra of these species immobilized onto an ellectrochemically roughen silver electrode. Changes in enhancement and wavenumber of proper bands upon adsorption on different silver surfaces are consistent with BN and its analogues adsorption primarily through Trp(8). Slightly different adsorption states of these molecules are observed depending upon natural amino acids substitution. For example, the indole ring in all the peptides interacts with silver nanoparticles in a edge-on orientation. It is additionally coordinated to the silver through the N(1)--H bond for all the peptides, except [Phe(12)]BN. This is in contrary to the results obtained for the silver roughen electrode that show direct but not strong N(1)--H/Ag interaction for all peptides except [D-Phe(12),Leu(14)]BN and [Leu(13)-(R)-Leu(14)]BN. For BN only C==O is not involved in the chemical coordination with the colloidal surface. [Lys(3)]BN and BN also adsorb with the C--N bond of NH(2) group normal and horizontal, respectively, to the colloidal surface, whereas C--NH(2) in other peptides is tilted to this surface. Also, the Trp(8) --CH(2)-- moiety of only [Tyr(4)]BN, [Lys(3)]BN, and [Tyr(4),D-Phe(12)]BN coordinates to Ag, whereas the Phe(12) ring of [Phe(12)]BN, [Tyr(4),D-Phe(12)]BN, and [D-Phe(12),Leu(14)]BN assists in the peptides binding only on the colloidal silver. (c) 2008 Wiley Periodicals, Inc.

  12. Analogue to Digital and Digital to Analogue Converters (ADCs and DACs): A Review Update

    CERN Document Server

    Pickering, J.

    2015-06-15

    This is a review paper updated from that presented for CAS 2004. Essentially, since then, commercial components have continued to extend their performance boundaries but the basic building blocks and the techniques for choosing the best device and implementing it in a design have not changed. Analogue to digital and digital to analogue converters are crucial components in the continued drive to replace analogue circuitry with more controllable and less costly digital processing. This paper discusses the technologies available to perform in the likely measurement and control applications that arise within accelerators. It covers much of the terminology and 'specmanship' together with an application-oriented analysis of the realisable performance of the various types. Finally, some hints and warnings on system integration problems are given.

  13. Hydrophobic and electrostatic interactions between cell penetrating peptides and plasmid DNA are important for stable non-covalent complexation and intracellular delivery.

    Science.gov (United States)

    Upadhya, Archana; Sangave, Preeti C

    2016-10-01

    Cell penetrating peptides are useful tools for intracellular delivery of nucleic acids. Delivery of plasmid DNA, a large nucleic acid, poses a challenge for peptide mediated transport. The paper investigates and compares efficacy of five novel peptide designs for complexation of plasmid DNA and subsequent delivery into cells. The peptides were designed to contain reported DNA condensing agents and basic cell penetrating sequences, octa-arginine (R 8 ) and CHK 6 HC coupled to cell penetration accelerating peptides such as Bax inhibitory mutant peptide (KLPVM) and a peptide derived from the Kaposi fibroblast growth factor (kFGF) membrane translocating sequence. A tryptophan rich peptide, an analogue of Pep-3, flanked with CH 3 on either ends was also a part of the study. The peptides were analysed for plasmid DNA complexation, protection of peptide-plasmid DNA complexes against DNase I, serum components and competitive ligands by simple agarose gel electrophoresis techniques. Hemolysis of rat red blood corpuscles (RBCs) in the presence of the peptides was used as a measure of peptide cytotoxicity. Plasmid DNA delivery through the designed peptides was evaluated in two cell lines, human cervical cancer cell line (HeLa) and (NIH/3 T3) mouse embryonic fibroblasts via expression of the secreted alkaline phosphatase (SEAP) reporter gene. The importance of hydrophobic sequences in addition to cationic sequences in peptides for non-covalent plasmid DNA complexation and delivery has been illustrated. An alternative to the employment of fatty acid moieties for enhanced gene transfer has been proposed. Comparison of peptides for plasmid DNA complexation and delivery of peptide-plasmid DNA complexes to cells estimated by expression of a reporter gene, SEAP. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  14. Tetrazine-Containing Amino Acid for Peptide Modification and Live Cell Labeling.

    Directory of Open Access Journals (Sweden)

    Zhongqiu Ni

    Full Text Available A novel amino acid derivative 3-(4-(1, 2, 4, 5-tetrazine-3-yl phenyl-2-aminopropanoic acid was synthesized in this study. The compound possessed better water-solubility and was synthesized more easily compared with the well-known and commercially available 3-(p-benzylamino-1, 2, 4, 5-tetrazine. Tetrazine-containing amino acid showed excellent stability in biological media and might be used for cancer cell labeling. Moreover, the compound remained relatively stable in 50% TFA/DCM with little decomposition after prolonged exposure at room temperature. The compound could be utilized as phenylalanine or tyrosine analogue in peptide modification, and the tetrazine-containing peptide demonstrated more significant biological activity than that of the parent peptide. The combination of tetrazine group and amino acid offered broad development prospects of the bioorthogonal labeling and peptide synthesis.

  15. Antinociceptive effects of dalargin and analogues

    Czech Academy of Sciences Publication Activity Database

    Pencheva, N.; Topouzov, I.; Barthová, J.; Barth, Tomislav

    2002-01-01

    Roč. 55, č. 11 (2002), s. 65-70 ISSN 0861-1459. [Bulgarian Symposium on Peptides /3./. Panichishte, 17.05.2002-19.05.2002] Institutional research plan: CEZ:AV0Z4055905 Keywords : opioids * enkephalins Subject RIV: CE - Biochemistry

  16. Experimental and Theoretical Studies of the Structures and Interactions of Vancomycin Antibiotics with Cell Wall Analogues

    International Nuclear Information System (INIS)

    Yang, Zhibo; Vorpagel, Erich R.; Laskin, Julia

    2008-01-01

    Surface-induced dissociation (SID) of the singly protonated complex of vancomycin antibiotic with cell wall peptide analogue (N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala) was studied using a 6 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FT-ICR MS) specially configured for SID experiments. The binding energy between the vancomycin and the peptide was obtained from the RRKM modeling of the time- and energy resolved fragmentation efficiency curves (TFECs) of the precursor ion and its fragments. Electronic structure calculations of the geometries, proton affinities and binding energies were performed for several model systems including vancomycin (V), vancomycin aglycon (VA), N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala, and non-covalent complexes of VA with N-acetyl-D-Ala-D-Ala and N α , N # var e psilon#-diacetyl-L-Lys-D-Ala-D-Ala at the B3LYP/6-31G(d) level of theory. Comparison between the experimental and computational results suggests that the most probable structure of the complex observed in our experiments corresponds to the neutral peptide bound to the vancomycin protonated at the secondary amino group of the N-methyl-leucine residue. The experimental binding energy of 30.9 ± 1.8 kcal/mol is in good agreement with the binding energy of 29.3 ± 2.5 kcal/mol calculated for the model system representing the preferred structure of the complex

  17. Comparative analysis of internalisation, haemolytic, cytotoxic and antibacterial effect of membrane-active cationic peptides: aspects of experimental setup.

    Science.gov (United States)

    Horváti, Kata; Bacsa, Bernadett; Mlinkó, Tamás; Szabó, Nóra; Hudecz, Ferenc; Zsila, Ferenc; Bősze, Szilvia

    2017-06-01

    Cationic peptides proved fundamental importance as pharmaceutical agents and/or drug carrier moieties functioning in cellular processes. The comparison of the in vitro activity of these peptides is an experimental challenge and a combination of different methods, such as cytotoxicity, internalisation rate, haemolytic and antibacterial effect, is necessary. At the same time, several issues need to be addressed as the assay conditions have a great influence on the measured biological effects and the experimental setup needs to be optimised. Therefore, critical comparison of results from different assays using representative examples of cell penetrating and antimicrobial peptides was performed and optimal test conditions were suggested. Our main goal was to identify carrier peptides for drug delivery systems of antimicrobial drug candidates. Based on the results of internalisation, haemolytic, cytotoxic and antibacterial activity assays, a classification of cationic peptides is advocated. We found eight promising carrier peptides with good penetration ability of which Penetratin, Tat, Buforin and Dhvar4 peptides showed low adverse haemolytic effect. Penetratin, Transportan, Dhvar4 and the hybrid CM15 peptide had the most potent antibacterial activity on Streptococcus pneumoniae (MIC lower than 1.2 μM) and Transportan was effective against Mycobacterium tuberculosis as well. The most selective peptide was the Penetratin, where the effective antimicrobial concentration on pneumococcus was more than 250 times lower than the HC 50 value. Therefore, these peptides and their analogues will be further investigated as drug delivery systems for antimicrobial agents.

  18. Dendropsophin 1, a novel antimicrobial peptide from the skin secretion of the endemic Colombian frog Dendropsophus columbianus.

    Science.gov (United States)

    Triana-Vidal, Luz Elena; Castro, Mariana Souza; Pires Júnior, Osmindo Rodrigues; Álvares, Alice Cunha Morales; de Freitas, Sonia Maria; Fontes, Wagner; Vargas, Jimmy Alexander Guerrero; Zúñiga-Baos, Jorge Alberto; Correia Batista, Isabel de Fátima; Grellier, Philippe; Charneau, Sébastien

    2018-06-01

    In efforts to find new antimicrobial peptides (AMPs), we studied the skin secretion of the endemic Colombian frog Dendropsophus columbianus belonging to a genus that has not been investigated previously. From HPLC-fractionated secretion, we identified one peptide with slightly antibacterial activity. Its peptide sequence showed no sequence similarity to current annotated peptides. We named this novel peptide dendropsophin 1 (Dc1). Afterward, two analogues were designed (Dc1.1 and Dc1.2) to improve the cationic and amphipathic features. Then, their antiproliferative and cytotoxic properties were evaluated against several pathogens including bacteria, fungi, protozoa and also mammalian cells. Dc1 and its two analogues exhibited moderate antibacterial activities and no hemolytic and cytotoxic effects on mammalian cells. Analogue Dc1.2 showed slightly improved antibacterial properties. Their secondary structures were characterised using CD spectroscopy and Dc1.2 displayed a higher α-helix content and thermal stability compared to Dc1 and Dc1.1 in hydrophobic experimental conditions.

  19. A silyl andrographolide analogue suppresses Wnt/β-catenin signaling pathway in colon cancer.

    Science.gov (United States)

    Reabroi, Somrudee; Chairoungdua, Arthit; Saeeng, Rungnapha; Kasemsuk, Teerapich; Saengsawang, Witchuda; Zhu, Weiming; Piyachaturawat, Pawinee

    2018-05-01

    Hyperactivation of Wnt/β-catenin signaling implicated in oncogenesis of colorectal cancer (CRC) is a potential molecular target for chemotherapy. An andrographolide analogue, 3A.1 (19-tert-butyldiphenylsilyl-8, 17-epoxy andrographolide) has previously been reported to be potently cytotoxic toward cancer cells by unknown molecular mechanisms. The present study explored the anti-cancer activity of analogue 3A.1 on Wnt/β-catenin signaling in colon cancer cells (HT29 cells) which were more sensitive to the others (HCT116 and SW480 cells). Analogue 3A.1 inhibited viability of HT29 cells with IC 50 value of 11.1 ± 1.4 μM at 24 h, which was more potent than that of the parent andrographolide. Analogue 3A.1 also suppressed the proliferation of HT29 cells and induced cell apoptosis in a dose-dependent manner. Its apoptotic activity was accompanied with increased expressions of proteins related to DNA damages; PARP-1 and γ-H2AX. In addition, analogue 3A.1 significantly inhibited T-cell factor and lymphoid enhancer factor (TCF/LEF) promoter activity of Wnt/β-catenin signaling. Accordingly, the expressions of Wnt target genes and β-catenin protein were suppressed. Moreover, analogue 3A.1 increased the activity of GSK-3β kinase, which is a negative regulator responsible for degradation of intracellular β-catenin. This mode of action was further supported by the absence of the effects after treatment with a GSK-3β inhibitor, and over-expression of a mutant β-catenin (S33Y). Our findings reveal, for the first time, an insight into the molecular mechanism of the anti-cancer activity of analogue 3A.1 through the inhibition of Wnt/β-catenin/GSK-3β pathway and provide a therapeutic potential of the andrographolide analogue 3A.1 in CRC treatment. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  20. Peptide YY3-36 and glucagon-like peptide-1 in functional dyspepsia. Secretion and role in symptom generation

    DEFF Research Database (Denmark)

    Witte, Anne-Barbara; Hilsted, Linda; Holst, Jens Juul

    2016-01-01

    method. Secondly, participants drank 75 mL (90 kcal) per five min until maximal satiety. PYY3-36, GLP-1, glucose, and insulin concentrations were assessed. Satiety measures and dyspeptic symptoms were registered using visual analogue scales. RESULTS: Gastric emptying, glucose, PYY3-36, and GLP-1......OBJECTIVE: The role of peptide YY3-36 (PYY3-36), glucagon-like peptide-1 (GLP-1), and glucose homoeostasis in symptom development in functional dyspepsia (FD) is unclear. The aim was to investigate postprandial changes in plasma PYY3-36, GLP-1, glucose and insulin, and the relationship between PYY3......-36, GLP-1, dyspeptic symptoms, and satiety measurements. MATERIALS AND METHODS: Thirty-six patients with functional dyspepsia and 18 healthy controls consumed a liquid meal at two occasions. Firstly, a fixed amount of 250 mL (300 kcal) was consumed and gastric emptying was assessed using the paracetamol...

  1. Structural Basis for Antigenic Peptide Recognition and Processing by Endoplasmic Reticulum (ER) Aminopeptidase 2.

    Science.gov (United States)

    Mpakali, Anastasia; Giastas, Petros; Mathioudakis, Nikolas; Mavridis, Irene M; Saridakis, Emmanuel; Stratikos, Efstratios

    2015-10-23

    Endoplasmic reticulum (ER) aminopeptidases process antigenic peptide precursors to generate epitopes for presentation by MHC class I molecules and help shape the antigenic peptide repertoire and cytotoxic T-cell responses. To perform this function, ER aminopeptidases have to recognize and process a vast variety of peptide sequences. To understand how these enzymes recognize substrates, we determined crystal structures of ER aminopeptidase 2 (ERAP2) in complex with a substrate analogue and a peptidic product to 2.5 and 2.7 Å, respectively, and compared them to the apo-form structure determined to 3.0 Å. The peptides were found within the internal cavity of the enzyme with no direct access to the outside solvent. The substrate analogue extends away from the catalytic center toward the distal end of the internal cavity, making interactions with several shallow pockets along the path. A similar configuration was evident for the peptidic product, although decreasing electron density toward its C terminus indicated progressive disorder. Enzymatic analysis confirmed that visualized interactions can either positively or negatively impact in vitro trimming rates. Opportunistic side-chain interactions and lack of deep specificity pockets support a limited-selectivity model for antigenic peptide processing by ERAP2. In contrast to proposed models for the homologous ERAP1, no specific recognition of the peptide C terminus by ERAP2 was evident, consistent with functional differences in length selection and self-activation between these two enzymes. Our results suggest that ERAP2 selects substrates by sequestering them in its internal cavity and allowing opportunistic interactions to determine trimming rates, thus combining substrate permissiveness with sequence bias. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. 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.

  3. 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.

  4. Rapid screening and structural elucidation of a novel sibutramine analogue in a weight loss supplement: 11-desisobutyl-11-benzylsibutramine.

    Science.gov (United States)

    Mans, Daniel J; Gucinski, Ashley C; Dunn, Jamie D; Gryniewicz-Ruzicka, Connie M; Mecker-Pogue, Laura C; Kao, Jeff L-F; Ge, Xia

    2013-09-01

    A novel analogue of sibutramine, 11-desisobutyl-11-benzylsibutramine, has been discovered. During routine ion mobility spectrometry (IMS) screening of a weight loss supplement collected at an US FDA import operation facility an unknown peak was observed. Further analysis of the supplement by liquid chromatography-mass spectrometry (LC-MS) and high resolution mass spectrometry revealed an unknown peak with a relative retention time of 1.04 with respect to sibutramine and a predicted formula of C20H24NCl. In order to elucidate the analogue's structure, it was isolated from the supplement and characterized by tandem mass spectrometry and nuclear magnetic resonance (NMR), which revealed the analogue possessed a benzyl moiety at the 11 position in place of the isobutyl group associated with sibutramine. Copyright © 2013. Published by Elsevier B.V.

  5. Influence of trace aromatics on the chemical growth mechanisms of Titan aerosol analogues

    Science.gov (United States)

    Gautier, Thomas; Sebree, Joshua A.; Li, Xiang; Pinnick, Veronica T.; Grubisic, Andrej; Loeffler, Mark J.; Getty, Stephanie A.; Trainer, Melissa G.; Brinckerhoff, William B.

    2017-06-01

    The chemical structure and formation pathways of Titan aerosols remain largely unknown. In this work, we studied the effect of trace aromatics on the chemical composition and formation pathways of laboratory analogues of Titan's organic aerosols. The aerosol analogues were produced using four different trace aromatic molecules, comprised of one or two aromatic rings, each with or without a nitrogen heteroatom. Samples were then analyzed by laser desorption/ionization Mass Spectrometry (LDMS), revealing a high variability in the sample composition depending on the trace aromatic used. Our work reveals that the final chemical structure of the aerosols depends strongly on the number of aromatic rings in the trace molecule, leading either to a polymeric or to a random co-polymeric growth of the sample. These different chemical structures can affect the physical properties of the aerosol. Future analysis of Titan's aerosols using better resolution could potentially determine whether either of the growth hypotheses are preferred.

  6. Breast cancer imaging using radiolabelled somatostatin analogues

    International Nuclear Information System (INIS)

    Dalm, Simone U.; Melis, Marleen; Emmering, Jasper; Kwekkeboom, Dik J.; Jong, Marion de

    2016-01-01

    Imaging and therapy using radiolabelled somatostatin analogues are methods successfully used in patients with somatostatin receptor (SSTR)-expressing neuroendocrine tumours. Since these techniques were first introduced, many improvements have been made. SSTR expression has also been reported on breast cancer (BC). Currently mammography, magnetic resonance imaging and ultrasound are the most frequent methods used for BC imaging. Since SSTR expression on BC was demonstrated, clinical studies examining the feasibility of visualizing primary BC using SSTR radioligands have been performed. However, to date SSTR-mediated nuclear imaging is not used clinically in BC patients. The aim of this review is to assess whether recent improvements made within nuclear medicine may enable SSTR-mediated imaging to play a role in BC management. For this we critically analysed results of past studies and discussed the potential of the improvements made within nuclear medicine on SSTR-mediated nuclear imaging of BC. Seven databases were searched for publications on BC imaging with SSTR radioligands. The papers found were analysed by 3 individual observers to identify whether the studies met the pre-set inclusion criteria defined as studies in which nuclear imaging using radiolabelled SST analogues was performed in patients with breast lesions. Twenty-four papers were selected for this review including studies on SSTR-mediated nuclear imaging in BC, neuroendocrine BC and other breast lesions. The analysed studies were heterogeneous with respect to the imaging method, imaging protocol, patient groups and the radiolabelled SST analogues used. Despite the fact that the analysed studies were heterogeneous, sensitivity for primary BC ranged from 36–100%. In a subset of the studies LN lesions were visualized, but sensitivity was lower compared to that for primary tumours. A part of the studies included benign lesions and specificity ranged from 22–100%. Furthermore, false negatives and

  7. The Greenland analogue project. Yearly report 2010

    Energy Technology Data Exchange (ETDEWEB)

    Harper, J; Brinkerhoff, D; Johnson, J [University of Montana, Missoula (United States); Ruskeeniemi, T; Engstroem, J; Kukkonen, I [Geological Survey of Finland (Finland); and others

    2012-04-15

    A four-year field and modelling study of the Greenland ice sheet and subsurface conditions, Greenland Analogue Project (GAP), has been initiated collaboratively by SKB, Posiva and NWMO to advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository. The study site encompasses a land terminus portion of the Greenland ice sheet, east of Kangerlussuaq, and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project begins in 2009 and is scheduled for completion in 2012. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with cold climate conditions and glacial cycles, and their impact on the long-term performance of deep geological repositories for spent nuclear fuel, will be significantly improved by studying a modern analogue. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a better understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. This report was produced by the GAP team members and presents an overview of the activities within the GAP during the interval January 1 to December 31, 2010, as well as research results obtained during this time frame. Research for the GAP is ongoing, and additional results related to the data presented here may become available in the future and will be presented in subsequent annual reports. (orig.)

  8. The Greenland analogue project. Yearly report 2010

    International Nuclear Information System (INIS)

    Harper, J.; Brinkerhoff, D.; Johnson, J.; Ruskeeniemi, T.; Engstroem, J.; Kukkonen, I.

    2012-04-01

    A four-year field and modelling study of the Greenland ice sheet and subsurface conditions, Greenland Analogue Project (GAP), has been initiated collaboratively by SKB, Posiva and NWMO to advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository. The study site encompasses a land terminus portion of the Greenland ice sheet, east of Kangerlussuaq, and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project begins in 2009 and is scheduled for completion in 2012. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with cold climate conditions and glacial cycles, and their impact on the long-term performance of deep geological repositories for spent nuclear fuel, will be significantly improved by studying a modern analogue. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a better understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. This report was produced by the GAP team members and presents an overview of the activities within the GAP during the interval January 1 to December 31, 2010, as well as research results obtained during this time frame. Research for the GAP is ongoing, and additional results related to the data presented here may become available in the future and will be presented in subsequent annual reports. (orig.)

  9. Pharmacologic Effects in vivo in Brain by Vector-Mediated Peptide Drug Delivery

    Science.gov (United States)

    Bickel, Ulrich; Yoshikawa, Takayoshi; Landaw, Elliot M.; Faull, Kym F.; Pardridge, William M.

    1993-04-01

    Pharmacologic effects in brain caused by systemic administration of neuropeptides are prevented by poor transport of the peptide through the brain vascular endothelium, which comprises the blood-brain barrier in vivo. In the present study, successful application of a chimeric peptide approach to enhance drug delivery through the blood-brain barrier for the purpose of achieving a central nervous system pharmacologic effect is described. The chimeric peptide was formed by linkage of a potent vasoactive intestinal peptide (VIP) analogue, which had been monobiotinylated, to a drug transport vector. The vector consisted of a covalent conjugate of avidin and the OX26 monoclonal antibody to the transferrin receptor. Owing to the high concentration of transferrin receptors on brain capillary endothelia, OX26 targets brain and undergoes receptor-mediated transcytosis through the blood-brain barrier. Systemic infusion of low doses (12 μg/kg) of the VIP chimeric peptide in rats resulted in an in vivo central nervous system pharmacologic effect: a 65% increase in cerebral blood flow. Biotinylated VIP analogue without the brain transport vector was ineffective.

  10. Rational Design of Cyclic Antimicrobial Peptides Based on BPC194 and BPC198

    Directory of Open Access Journals (Sweden)

    Anna D. Cirac

    2017-06-01

    Full Text Available A strategy for the design of antimicrobial cyclic peptides derived from the lead compounds c(KKLKKFKKLQ (BPC194 and c(KLKKKFKKLQ (BPC198 is reported. First, the secondary β-structure of BPC194 and BPC198 was analyzed by carrying out molecular dynamics (MD simulations. Then, based on the sequence pattern and the β-structure of BPC194 or BPC198, fifteen analogues were designed and synthesized on solid-phase. The best peptides (BPC490, BPC918, and BPC924 showed minimum inhibitory concentration (MIC values <6.2 μM against Pseudomonas syringae pv. syringae and Xanthomonas axonopodis pv. vesicatoria, and an MIC value of 12.5 to 25 μM against Erwinia amylovora, being as active as BPC194 and BPC198. Interestingly, these three analogues followed the structural pattern defined from the MD simulations of the parent peptides. Thus, BPC490 maintained the parallel alignment of the hydrophilic pairs K1–K8, K2–K7, and K4–K5, whereas BPC918 and BPC924 included the two hydrophilic interactions K3–Q10 and K5–K8. In short, MD simulations have proved to be very useful for ascertaining the structural features of cyclic peptides that are crucial for their biological activity. Such approaches could be further employed for the development of new antibacterial cyclic peptides.

  11. The Lehmer Matrix and Its Recursive Analogue

    Science.gov (United States)

    2010-01-01

    LU factorization of matrix A by considering det A = det U = ∏n i=1 2i−1 i2 . The nth Catalan number is given in terms of binomial coefficients by Cn...for failing to comply with a collection of information if it does not display a currently valid OMB control number . 1. REPORT DATE 2010 2. REPORT...TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE The Lehmer matrix and its recursive analogue 5a. CONTRACT NUMBER 5b

  12. Nuclear waste geochemistry: natural and anthropic analogues

    International Nuclear Information System (INIS)

    Petit, J.C.

    1997-01-01

    The geochemical evolution of nuclear waste storage is difficult to describe, due to the long time scales involved, the radioactivity confinement complexity and the un-natural radionuclides which evolution is not known. In order to carry out a long term prediction, a special approach is used, based on a combination of experiments conducted in laboratories and in situ, modelizations and comparisons with process and material analogues (natural or man-made, such as basaltic and rhyolitic volcanic glasses, plutonium, historical and archaeological artefacts)

  13. Electronic analogue simulator of radio cardiograms

    International Nuclear Information System (INIS)

    Roux, G.; Lansiart, A.; Vernejoul, P. de; Kellershohn, C.

    1967-01-01

    The various parameters of the heart pump and of the blood circulation can be determined by radio-cardio-graphical techniques. The curves thus obtained can be more easily used in radiocardiography if the electronic analogue simulator described here is employed. The experimental and simulated radio-cardiograms are made to coincide by varying the electrical parameters of the simulator. Using simple charts it is possible to obtain directly the actual original physiological parameters from these electrical parameters. Some examples are given showing the excellent accuracy obtained in the determination of ejection indices by the simulator. (authors) [fr

  14. Natural Analogues of CO2 Geological Storage

    International Nuclear Information System (INIS)

    Perez del Villar, L.; Pelayo, M.; Recreo, F.

    2007-01-01

    Geological storage of carbon dioxide is nowadays, internationally considered as the most effective method for greenhouse gas emission mitigation, in order to minimize the global climate change universally accepted. Nevertheless, the possible risks derived of this long-term storage have a direct influence on its public acceptance. Among the favourable geological formations to store CO2, depleted oil and gas fields, deep saline reservoirs, and unamiable coal seams are highlighted. One of the most important objectives of the R and D projects related to the CO2 geological storage is the evaluation of the CO2 leakage rate through the above mentioned geological formations. Therefore, it is absolutely necessary to increase our knowledge on the interaction among CO2, storage and sealing formations, as well as on the flow paths and the physical resistance of the sealing formation. The quantification of the CO2 leakage rate is essential to evaluate the effects on the human and animal health, as well as for the ecosystem and water quality. To achieve these objectives, the study of the natural analogues is very useful in order to know the natural leakage rate to the atmosphere, its flow paths, the physical, chemical and mineralogical modifications due to the long term interaction processes among the CO2 and the storage and sealing formations, as well as the effects on the groundwaters and ecosystems. In this report, we have tried to summarise the main characteristics of the natural reservoirs and surficial sources of CO2, which are both natural analogues of the geological storage and CO2 leakage, studied in EEUU, Europe and Australia. The main objective of this summary is to find the possible applications for long-term risk prediction and for the performance assessment by means of conceptual and numerical modelling, which will allow to validate the predictive models of the CO2 storage behaviour, to design and develop suitable monitoring techniques to control the CO2 behaviour

  15. Digital and analogue industrial radiography, application fields

    International Nuclear Information System (INIS)

    Willems, Peter; Millord, Erik Yardin

    2000-01-01

    Full text: Reusable phosphor screens for computer radiography (CR), amorphous selenium screens for direct radiography (DR), film digitalisation (FD) constitute imaging methods accepted by industry and are used for non-destructive radiographic testing (RT). Economic pressures are involving and affecting digital RT technology. Standards and codes for film radiography and radioscopy qualification do no longer cover the wide range of digital RT applications. It will be our task to optimise the performance of digital RT characterisation and to create appropriate examination methods to use all these new and existent technologies. In the meantime, an increasing automation and control of manual methods of analogue radiography can as well be expected. (author)

  16. The anti-inflammatory activity of dillapiole and some semisynthetic analogues.

    Science.gov (United States)

    Parise-Filho, Roberto; Pastrello, Michelli; Pereira Camerlingo, Carla Emygdio; Silva, Gisele Juni; Agostinho, Leonardo Aguiar; de Souza, Thaís; Motter Magri, Fátima Maria; Ribeiro, Roberto Rodrigues; Brandt, Carlos Alberto; Polli, Michelle Carneiro

    2011-11-01

    Piper aduncum L. (Piperaceae) produces an essential oil (dillapiole) with great exploitative potential and it has proven effects against traditional cultures of phytopathogens, such as fungi, bacteria and mollusks, as well as analgesic action with low levels of toxicity. This study investigated the in vivo anti-inflammatory activity of dillapiole. Furthermore, in order to elucidate its structure-anti-inflammatory activity relationship (SAR), semisynthetic analogues were proposed by using the molecular simplification strategy. Dillapiole and safrole were isolated and purified using column chromatography. The semisynthetic analogues were obtained by using simple organic reactions, such as catalytic reduction and isomerization. All the analogues were purified by column chromatography and characterized by (1)H and (13)C NMR. The anti-inflammatory activities of dillapiole and its analogues were studied in carrageenan-induced rat paw edema model. Dillapiole and di-hydrodillapiole significantly (p<0.05) inhibited rat paw edema. All the other substances tested, including safrole, were less powerful inhibitors with activities inferior to that of indomethacin. These findings showed that dillapiole and di-hydrodillapiole have moderate anti-phlogistic properties, indicating that they can be used as prototypes for newer anti-inflammatory compounds. Structure-activity relationship studies revealed that the benzodioxole ring is important for biological activity as well as the alkyl groups in the side chain and the methoxy groups in the aromatic ring.

  17. Opposite responses of rabbit and human globin mRNAs to translational inhibition by cap analogues

    International Nuclear Information System (INIS)

    Shakin, S.H.; Liebhaber, S.A.

    1987-01-01

    The translational efficiency of an mRNA may be determined at the step of translational initiation by the efficiency of its interaction with the cap binding protein complex. To further investigate the role of these interactions in translational control, the authors compare in vitro the relative sensitivities of rabbit and human α- and β-globin mRNAs to translational inhibition by cap analogues. They find that rabbit β-globin mRNA is more resistant to translational inhibition by cap analogues than rabbit α-globin mRNA, while in contrast, human β-globin mRNA is more sensitive to cap analogue inhibition than human α- and β-globin mRNAs is unexpected as direct in vivo and in vitro comparisons of polysome profiles reveal parallel translational handling of the α- and β-globin mRNAs from these two species. This discordance between the relative translational sensitivities of these mRNAs to cap analogues and their relative ribosome loading activities suggests that cap-dependent events may not be rate limiting in steady-state globin translation

  18. Acylation of Therapeutic Peptides

    DEFF Research Database (Denmark)

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

    ) , which promotes intestinal growth and is used to treat bowel disorders such as inflammatory bowel diseases and short bowel syndrome, and the 32 amino acid salmon calcitonin (sCT), which lowers blood calcium and is employed in the treatment of post-menopausal osteoporosis and hypercalcemia. The two...... peptides are similar in size and structure, but oppositely charged at physiological pH. Both peptides were acylated with linear acyl chains of systematically increasing length, where sCT was furthermore acylated at two different positions on the peptide backbone. For GLP-2, we found that increasing acyl...... remained optimal overall. The results indicate that rational acylation of GLP-2 can increase its in vitro intestinal absorption, alone or in combination with permeation enhancers, and are consistent with the initial project hypothesis. For sCT, an unpredicted effect of acylation largely superseded...

  19. Lead Diversification through a Prins-Driven Macrocyclization Strategy: Application to C13-Diversified Bryostatin Analogues.

    Science.gov (United States)

    Wender, Paul A; Billingsley, Kelvin L

    2013-01-01

    The design, synthesis, and biological evaluation of a novel class of C13-diversified bryostatin analogues are described. An innovative and general strategy based on a Prins macrocyclization-nucleophilic trapping cascade was used to achieve late-stage diversification. In vitro analysis of selected library members revealed that modification at the C13 position of the bryostatin scaffold can be used as a diversification handle to regulate biological activity.

  20. Development of 99mTc labelled somatostatin analogues and evaluation of their radiochemical and biological behaviour

    International Nuclear Information System (INIS)

    Gano, L.; Patricio, L.

    2001-01-01

    Conjugates of two somatostatin analogues, octreotide and RC-160, with HYNIC were synthesized, characterized and purified by reverse phase HPLC. Radiolabelling of the conjugates with 99m Tc was achieved using tricine as co-ligand. High labelling efficiencies were obtained and 99m Tc peptides with high radiochemical purity were found when analysed both by ITLC and HPLC. In vitro stability of 99m Tc-peptides in human serum and towards cysteine challenge was determined by Cellogel electrophoresis and HPLC after ultrafiltration of serum solution through a 20 kDa cut off membrane. Biodistribution studies were performed in healthy mice at 5 and 30 minutes and 1, 2, 4 and 24 h post-injection. Urine and blood samples were collected at sacrifice time. Samples of urine and ultrafiltrate murine serum were analysed by electrophoresis and reverse phase HPLC in order to get some information about radiocompounds metabolism. Biological distribution of 99m Tc octreotide was also assayed in mice pre-treated with an excess of unlabelled peptide. From our results we conclude that this labelling method led to stable 99m Tc complexes both in vitro and in vivo when high specific activities (37-72 GBq/μmole) were used. Biodistribution studies of both 99m Tc-peptides indicated a radioactivity distribution profile with significant differences especially in the liver uptake that is higher for 99m Tc RC-160. However, a rapid blood clearance was obtained for both radiolabelled peptides, and the urine analysis indicated that 99m Tc peptide is mostly excreted as the initial complex. Pre-treatment with unlabelled peptide did not affect renal excretion of 99m TOC but pancreas and intestine radioactive uptake was significantly lower, indicating saturation of somatostatin receptors and selective uptake. (author)

  1. 99mTechnetium labelled vasoactive intestinal peptide analogue for rapid localization of tumours in humans

    International Nuclear Information System (INIS)

    Thakur, M.L.; Pallela, V.; Marcus, C.S.; Diggles, L.; Pham, H.L.; Ahdoot, R.; Kalinowski, E.A.; Saeed, S.; Minami, C.

    2001-01-01

    In recent years, imaging tumours with receptor specific biomolecules has been the focus of increasing interest. VIP has a high affinity for specific receptors that are expressed in high density on a large number of malignant tumours. VIP was modified (TP 3654) without compromising its biological activity, and labelled with 99m Tc. Pharmacokinetics and feasibility studies were performed in three normal volunteers and 11 patients with a history of cancer. Imaging was performed for up to two h post-injection. Within 24 h after injection of 99m Tc-TP 3654 (10-15 mCi/5 μg), approximately 70% of the tracer cleared through the kidneys, and 20% through the liver. Blood clearance was rapid. No adverse reaction was noted in any subjects. All known tumours were clearly delineated within 20 min. Findings were compared with the results of 99m Tc-MIBI, CT, MRI, or histology. There was concordance in nine patients. In the other two, only the VIP scan was positive for tumours known to express VIP receptors. The early results of imaging tumours with 99m Tc-VIP are promising and warrant further studies. (author)

  2. Interaction of N-terminal peptide analogues of the Na+,K+-ATPase with membranes.

    Science.gov (United States)

    Nguyen, Khoa; Garcia, Alvaro; Sani, Marc-Antoine; Diaz, Dil; Dubey, Vikas; Clayton, Daniel; Dal Poggetto, Giovanni; Cornelius, Flemming; Payne, Richard J; Separovic, Frances; Khandelia, Himanshu; Clarke, Ronald J

    2018-06-01

    The Na + ,K + -ATPase, which is present in the plasma membrane of all animal cells, plays a crucial role in maintaining the Na + and K + electrochemical potential gradients across the membrane. Recent studies have suggested that the N-terminus of the protein's catalytic α-subunit is involved in an electrostatic interaction with the surrounding membrane, which controls the protein's conformational equilibrium. However, because the N-terminus could not yet be resolved in any X-ray crystal structures, little information about this interaction is so far available. In measurements utilising poly-l-lysine as a model of the protein's lysine-rich N-terminus and using lipid vesicles of defined composition, here we have identified the most likely origin of the interaction as one between positively charged lysine residues of the N-terminus and negatively charged headgroups of phospholipids (notably phosphatidylserine) in the surrounding membrane. Furthermore, to isolate which segments of the N-terminus could be involved in membrane binding, we chemically synthesized N-terminal fragments of various lengths. Based on a combination of results from RH421 UV/visible absorbance measurements and solid-state 31 P and 2 H NMR using these N-terminal fragments as well as MD simulations it appears that the membrane interaction arises from lysine residues prior to the conserved LKKE motif of the N-terminus. The MD simulations indicate that the strength of the interaction varies significantly between different enzyme conformations. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. U.S. Nuclear Regulatory Commission natural analogue research program

    International Nuclear Information System (INIS)

    Kovach, L.A.; Ott, W.R.

    1995-01-01

    This article describes the natural analogue research program of the U.S. Nuclear Regulatory Commission (US NRC). It contains information on the regulatory context and organizational structure of the high-level radioactive waste research program plan. It also includes information on the conditions and processes constraining selection of natural analogues, describes initiatives of the US NRC, and describes the role of analogues in the licensing process

  4. Conformationally restrained aromatic analogues of fosmidomycin and FR900098.

    Science.gov (United States)

    Kurz, Thomas; Schlüter, Katrin; Pein, Miriam; Behrendt, Christoph; Bergmann, Bärbel; Walter, Rolf D

    2007-07-01

    The synthesis and in-vitro antimalarial activity of conformationally restrained bis(pivaloyloxymethyl) ester analogues of the natural product fosmidomycin is presented. In contrast to alpha-aryl-substituted analogues, conformationally restrained aromatic analogues exhibit only moderate in-vitro antimalarial activity against the chloroquine-sensitive strain 3D7 of Plasmodium falciparum. The most active derivative displays an IC(50) value of 47 microM.

  5. Glucagon-like peptide-1 analogs against antipsychotic-induced weight gain

    DEFF Research Database (Denmark)

    Ebdrup, Bjørn H; Knop, Filip K; Ishøy, Pelle L

    2012-01-01

    between schizophrenia and overweight patients. DISCUSSION: Current interventions against antipsychotic-induced weight gain do not facilitate a substantial and lasting weight loss. GLP-1 analogues used in the treatment of type 2 diabetes are associated with significant and sustained weight loss...... are already compromised in normal weight patients with schizophrenia. Here we outline the current strategies against antipsychotic-induced weight gain, and we describe peripheral and cerebral effects of the gut hormone glucagon-like peptide-1 (GLP-1). Moreover, we account for similarities in brain changes...... in overweight patients. Potential effects of treating schizophrenia patients with antipsychotic-induced weight gain with GLP-1 analogues are discussed. CONCLUSIONS: We propose that adjunctive treatment with GLP-1 analogues may constitute a new avenue to treat and prevent metabolic and cerebral deficiencies...

  6. 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...

  7. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    of these are currently being used in quantitative structure--activity relationship (QSAR) studies for AMP optimization. Additionally, some key commercial computational tools are discussed, and both successful and less successful studies are referenced, illustrating some of the challenges facing AMP scientists. Through...... 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...

  8. Structure, Content, and Bioactivity of Food-Derived Peptides in the Body.

    Science.gov (United States)

    Sato, Kenji

    2018-03-28

    Orally administered peptides are assumed to be degraded into amino acids in the body. However, our recent studies revealed some food-derived prolyl and pyroglutamyl peptides with 2-3 amino acid residues in the blood of humans and animals, while most of the peptides in the endoproteinase digest of food protein are degraded by exopeptidase. Some food-derived dipeptides in the body display in vitro and in vivo biological activities. These facts indicate that the biological activities of food-derived peptides in the body rather than those in food are crucial to understanding the mechanism of the beneficial effects of orally administered peptides.

  9. Andrographolide and analogues in cancer prevention.

    Science.gov (United States)

    Mishra, Siddhartha Kumar; Tripathi, Swati; Shukla, Archana; Oh, Seung Hyun; Kim, Hwan Mook

    2015-01-01

    Andrographis paniculata is a medicinal plant traditionally used for treatment of cough and cold, fever, laryngitis, and several infectious diseases. Extracts of A. paniculata have shown versatile potency against various diseases including cancer. The active biomolecules of A. paniculata mainly are lactone and diterpene. Andrographolide and analogues have been widely used for prevention of different diseases. Andrographolides have shown potent antiinflammatory and anticancer activities. It showed potentials as chemopreventive agents by suppressing growth of cancer cells by inhibiting NF-kappaB, PI3K/AKT and other kinase pathways and by inducing apoptosis. Andrographolide induced both intrinsic and extrinsic apoptosis pathway in different cancer cells via expression of different anti-apoptotic protein like Bax, p53, and activated caspases. Andrographolide was successfully used as an antineoplastic drug in cancer chemotherapy. Andrographolide inhibited the growth of human breast, prostate, and hepatoma tumors. Andrographolide and analogues need to be subjected to further clinical and biomedical studies in cancer chemoprevention. Andrographolide could be potent anticancer agent when used in combination with other chemotherapeutic agents.

  10. Statistical analogues of thermodynamic extremum principles

    Science.gov (United States)

    Ramshaw, John D.

    2018-05-01

    As shown by Jaynes, the canonical and grand canonical probability distributions of equilibrium statistical mechanics can be simply derived from the principle of maximum entropy, in which the statistical entropy S=- {k}{{B}}{\\sum }i{p}i{log}{p}i is maximised subject to constraints on the mean values of the energy E and/or number of particles N in a system of fixed volume V. The Lagrange multipliers associated with those constraints are then found to be simply related to the temperature T and chemical potential μ. Here we show that the constrained maximisation of S is equivalent to, and can therefore be replaced by, the essentially unconstrained minimisation of the obvious statistical analogues of the Helmholtz free energy F = E ‑ TS and the grand potential J = F ‑ μN. Those minimisations are more easily performed than the maximisation of S because they formally eliminate the constraints on the mean values of E and N and their associated Lagrange multipliers. This procedure significantly simplifies the derivation of the canonical and grand canonical probability distributions, and shows that the well known extremum principles for the various thermodynamic potentials possess natural statistical analogues which are equivalent to the constrained maximisation of S.

  11. Marine Peptides and Their Anti-Infective Activities

    Directory of Open Access Journals (Sweden)

    Hee Kyoung Kang

    2015-01-01

    Full Text Available Marine bioresources are a valuable source of bioactive compounds with industrial and nutraceutical potential. Numerous clinical trials evaluating novel chemotherapeutic agents derived from marine sources have revealed novel mechanisms of action. Recently, marine-derived bioactive peptides have attracted attention owing to their numerous beneficial effects. Moreover, several studies have reported that marine peptides exhibit various anti-infective activities, such as antimicrobial, antifungal, antimalarial, antiprotozoal, anti-tuberculosis, and antiviral activities. In the last several decades, studies of marine plants, animals, and microbes have revealed tremendous number of structurally diverse and bioactive secondary metabolites. However, the treatments available for many infectious diseases caused by bacteria, fungi, and viruses are limited. Thus, the identification of novel antimicrobial peptides should be continued, and all possible strategies should be explored. In this review, we will present the structures and anti-infective activity of peptides isolated from marine sources (sponges, algae, bacteria, fungi and fish from 2006 to the present.

  12. Hydroxyapatite-binding peptides for bone growth and inhibition

    Science.gov (United States)

    Bertozzi, Carolyn R [Berkeley, CA; Song, Jie [Shrewsbury, MA; Lee, Seung-Wuk [Walnut Creek, CA

    2011-09-20

    Hydroxyapatite (HA)-binding peptides are selected using combinatorial phage library display. Pseudo-repetitive consensus amino acid sequences possessing periodic hydroxyl side chains in every two or three amino acid sequences are obtained. These sequences resemble the (Gly-Pro-Hyp).sub.x repeat of human type I collagen, a major component of extracellular matrices of natural bone. A consistent presence of basic amino acid residues is also observed. The peptides are synthesized by the solid-phase synthetic method and then used for template-driven HA-mineralization. Microscopy reveal that the peptides template the growth of polycrystalline HA crystals .about.40 nm in size.

  13. Antimicrobial Peptides: An Introduction.

    Science.gov (United States)

    Haney, Evan F; Mansour, Sarah C; Hancock, Robert E W

    2017-01-01

    The "golden era" of antibiotic discovery has long passed, but the need for new antibiotics has never been greater due to the emerging threat of antibiotic resistance. This urgency to develop new antibiotics has motivated researchers to find new methods to combat pathogenic microorganisms resulting in a surge of research focused around antimicrobial peptides (AMPs; also termed host defense peptides) and their potential as therapeutics. During the past few decades, more than 2000 AMPs have been identified from a diverse range of organisms (animals, fungi, plants, and bacteria). While these AMPs share a number of common features and a limited number of structural motifs; their sequences, activities, and targets differ considerably. In addition to their antimicrobial effects, AMPs can also exhibit immunomodulatory, anti-biofilm, and anticancer activities. These diverse functions have spurred tremendous interest in research aimed at understanding the activity of AMPs, and various protocols have been described to assess different aspects of AMP function including screening and evaluating the activities of natural and synthetic AMPs, measuring interactions with membranes, optimizing peptide function, and scaling up peptide production. Here, we provide a general overview of AMPs and introduce some of the methodologies that have been used to advance AMP research.

  14. GLP-1 analogues for neuroprotection after out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Wiberg, Sebastian; Hassager, Christian; Thomsen, Jakob Hartvig

    2016-01-01

    one-to-one fashion to a 6-hour and 15-minute infusion of either Exenatide or placebo. Patients are eligible for inclusion if resuscitated from cardiac arrest with randomization from 20 minutes to 240 minutes after return of spontaneous circulation. The co-primary endpoint is feasibility, defined......Background: Attenuating the neurological damage occurring after out-of-hospital cardiac arrest is an ongoing research effort. This dual-centre study investigates the neuroprotective effects of the glucagon-like-peptide-1 analogue Exenatide administered within 4 hours from the return of spontaneous...... circulation to comatose patients resuscitated from out-of-hospital cardiac arrest. Methods/design: This pilot study will randomize a total of 120 unconscious patients with sustained return of spontaneous circulation after out-of-hospital cardiac arrest undergoing targeted temperature management in a blinded...

  15. Exploring the biological consequences of conformational changes in aspartame models containing constrained analogues of phenylalanine.

    Science.gov (United States)

    Mollica, Adriano; Mirzaie, Sako; Costante, Roberto; Carradori, Simone; Macedonio, Giorgia; Stefanucci, Azzurra; Dvoracsko, Szabolcs; Novellino, Ettore

    2016-12-01

    The dipeptide aspartame (Asp-Phe-OMe) is a sweetener widely used in replacement of sucrose by food industry. 2',6'-Dimethyltyrosine (DMT) and 2',6'-dimethylphenylalanine (DMP) are two synthetic phenylalanine-constrained analogues, with a limited freedom in χ-space due to the presence of methyl groups in position 2',6' of the aromatic ring. These residues have shown to increase the activity of opioid peptides, such as endomorphins improving the binding to the opioid receptors. In this work, DMT and DMP have been synthesized following a diketopiperazine-mediated route and the corresponding aspartame derivatives (Asp-DMT-OMe and Asp-DMP-OMe) have been evaluated in vivo and in silico for their activity as synthetic sweeteners.

  16. PEGylation of {sup 99m}Tc-labeled bombesin analogues improves their pharmacokinetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Daepp, Simone; Garayoa, Elisa Garcia [Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, CH-5232 Villigen-PSI (Switzerland); Maes, Veronique; Brans, Luc; Tourwe, Dirk A. [Department of Organic Chemistry, Vrije Universiteit Brussel, 1050 Brussels (Belgium); Mueller, Cristina [Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, CH-5232 Villigen-PSI (Switzerland); Schibli, Roger, E-mail: roger.schibli@psi.ch [Paul Scherrer Institute, Center for Radiopharmaceutical Sciences ETH-PSI-USZ, CH-5232 Villigen-PSI (Switzerland); Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich (Switzerland)

    2011-10-15

    Introduction: Radiolabeled bombesin (BN) conjugates are promising radiotracers for imaging and therapy of breast and prostate tumors in which BN{sub 2}/gastrin-releasing peptide (GRP) receptors are overexpressed. However, the low in vivo stability of BN conjugates may limit their clinical application. In an attempt to improve their pharmacokinetics and counteract their rapid enzymatic degradation, we prepared a series of polyethylene glycol (PEG)-ylated BN(7-14) analogues for radiolabeling with {sup 99m}Tc(CO){sub 3} and evaluated them in vitro and in vivo. Methods: Derivatization of a stabilized (N{sup {alpha}H}is)Ac-BN(7-14)[Cha{sup 13},Nle{sup 14}] analogue with linear PEG molecules of various sizes [5 kDa (PEG{sub 5}), 10 kDa (PEG{sub 10}) and 20 kDa (PEG{sub 20})] was performed by PEGylation of the {epsilon}-amino group of a {beta}{sup 3}hLys-{beta}Ala-{beta}Ala spacer between the stabilized BN sequence and the (N{sup {alpha}H}is)Ac chelator. The analogues were then radiolabeled by employing the {sup 99m}Tc-tricarbonyl technique. Binding affinity and internalization/externalization studies were performed in vitro in human prostate carcinoma PC-3 cells. Stability was investigated in vitro in human plasma and in vivo in Balb/c mice. Finally, single photon emission computed tomography (SPECT)/X-ray computed tomography studies were performed in nude mice bearing PC-3 tumor xenografts. Results: PEGylation did not affect the binding affinity of BN analogues, as the binding affinity for BN{sub 2}/GRP receptors remained high (K{sub d}<0.9 nM). However, in vitro binding kinetics of the PEGylated analogues were slower. Steady-state condition was reached after 4 h, and the total cell binding was 10 times lower than that for the non-PEGylated counterpart. Besides, PEGylation improved the stability of BN conjugates in vitro and in vivo. The BN derivative conjugated with a PEG{sub 5} molecule showed the best pharmacokinetics in vivo, i.e., faster blood clearance and

  17. Space Analogue Environments: Are the Populations Comparable?

    Science.gov (United States)

    Sandal, G. M.

    Background: Much of our present understanding about psychology in space is based on studies of groups operating in so-called analogue environments where personnel are exposed to many of the same stressors as those experienced by astronauts in space. One possible problem with extrapolating results is that personnel operating in various hazardous and confined environments might differ in characteristics influencing coping, interaction, and performance. The object of this study was to compare the psychological similarity of these populations in order to get a better understanding of whether this extrapolation is justifiable. The samples investigated include polar crossings (N= 22), personnel on Antarctic research stations (N= 183), several military occupations (N= 187), and participants in space simulation studies (N=20). Methods: Personnel in each of these environments were assessed using the Personality Characteristic Inventory (PCI) and Utrecht Coping List (UCL). The PCI is a multidimensional trait assessment battery that measures various aspects of achievement orientation and social competence. The UCL is a questionnaire designed to assess habitual coping strategies when encountering stressful or demanding situations. Results: Only minor differences in use of habitual coping strategies were evident across the different samples. In relation to personality scores, the military subjects and participants in space simulation studies indicated higher competitiveness and negative instrumentality compared to both the personnel on Antarctic research stations and participants in polar expedition. Among the personnel on Antarctic research stations, significant gender differences were found with women scoring lower on competitiveness, negative instrumentality and impatience/irritability. Compared to the other samples, the participants in polar expeditions were found to be more homogeneous in personality and no significant gender differences were evident on the traits that

  18. Glaciation and geosphere evolution - Greenland Analogue Project

    International Nuclear Information System (INIS)

    Hirschorn, S.; Vorauer, A.; Belfadhel, M.B.; Jensen, M.

    2011-01-01

    The deep geological repository concept for the long-term management of used nuclear fuel involves the containment and isolation of used nuclear fuel in a suitable geological formation. A key objective of the Canadian Nuclear Waste Management Organization (NWMO) geoscience technical research program is to advance the understanding of geosphere stability and its resilience to perturbations over time frames of relevance to a deep geological repository. Glaciation has been identified as the most probable and intense perturbation relevant to a deep geological repository associated with long-term climate change in northern latitudes. Given that the North American continent has been re-glaciated nine times over the past million years, it is strongly expected that a deep geological repository within a suitable crystalline or sedimentary rock formation in Canada will be subject to glaciation events associated with long-term climate change. As such, NWMO's geoscience research program has placed particular emphasis on investigations of the response of the geosphere to glaciations. As surface conditions change from present day conditions to periglacial, followed by ice-sheet cover of variable thickness and rapid glacial retreat, transient geochemical, hydraulic, mechanical and temperature conditions will be simultaneously imposed on groundwater systems. NWMO research activities related to glaciation events and their impacts on groundwater system evolution are being undertaken using a multi-disciplinary approach aimed at collecting multiple lines of evidence. These investigations include assessment of the: Impact of an ice sheet on groundwater composition at repository depth using the Greenland Ice Sheet as an analogue to future glaciations in North America; Expected physical and temporal surface boundary conditions related to potential future glaciation events by estimating the magnitude and time rate of change of ice sheet thickness, ground surface temperature and

  19. Peptides in headlock ? a novel high-affinity and versatile peptide-binding nanobody for proteomics and microscopy

    OpenAIRE

    Braun, Michael B.; Traenkle, Bjoern; Koch, Philipp A.; Emele, Felix; Weiss, Frederik; Poetz, Oliver; Stehle, Thilo; Rothbauer, Ulrich

    2016-01-01

    Nanobodies are highly valuable tools for numerous bioanalytical and biotechnical applications. Here, we report the characterization of a nanobody that binds a short peptide epitope with extraordinary affinity. Structural analysis reveals an unusual binding mode where the extended peptide becomes part of a ?-sheet structure in the nanobody. This interaction relies on sequence-independent backbone interactions augmented by a small number of specificity-determining side chain contacts. Once boun...

  20. Host defence peptides in human burns.

    Science.gov (United States)

    Kaus, Aljoscha; Jacobsen, Frank; Sorkin, Michael; Rittig, Andrea; Voss, Bruno; Daigeler, Adrien; Sudhoff, Holger; Steinau, Hans-Ulrich; Steinstraesser, Lars

    2008-02-01

    The goal of this study was to analyse expression profiles of human epithelial host defence peptides in burned and unburned skin tissue, samples of which were obtained during debridements and snap-frozen in liquid nitrogen. Total RNA was isolated, and cDNA of epithelial host defence peptides and proteins (hCAP-18/LL-37, hBD1-hBD4, dermcidin, S100A7/psoriasin and RNAse7) was quantified by qRT-PCR. In situ hybridisation and immunohistochemical staining localised gene expression of hCAP-18/LL-37, hBD2 and hBD3 in histological sections. Most of the analysed host defence peptides and proteins showed higher mRNA levels in partial-thickness burns than in unburned tissue. In situ hybridisation revealed expression of hCAP-18/LL-37, hBD2 and hBD3 at the surface of burns that was independent of burn depth. However, the finding of higher host defence peptide gene expression rates does not correlate with the incidence of wound infection in burns. We hypothesise that the epithelial innate immune response in burns is complex.

  1. [Distiller Yeasts Producing Antibacterial Peptides].

    Science.gov (United States)

    Klyachko, E V; Morozkina, E V; Zaitchik, B Ts; Benevolensky, S V

    2015-01-01

    A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

  2. Neuroprotective effects of an oxyntomodulin analogue in the MPTP mouse model of Parkinson's disease.

    Science.gov (United States)

    Liu, WeiZhen; Li, Yanwei; Jalewa, Jaishree; Saunders-Wood, Taylor; Li, Lin; Hölscher, Christian

    2015-10-15

    Oxyntomodulin is a hormone and a growth factor. It activates two receptors, the Glucagon-like peptide 1 (GLP-1) and the glucagon receptor. GLP-1 mimetics are on the market as treatments for type 2 diabetes and are well tolerated. These drugs have shown neuroprotective properties in animal models of neurodegenerative disorders. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in animal models of Parkinson's disease (PD), and a clinical trial in PD patients showed promising first positive results. D-Ser2-oxyntomodulin (Oxy) is a protease resistant oxyntomodulin analogue that has been developed to treat diabetes. Here we demonstrate for the first time that such analogues have neuroprotective effects. The drug showed protective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP was injected daily (20 mg/kg i.p.) for 7 days, and Oxy injected once-daily for 14 days i.p. Oxy treatment prevented or reversed the MPTP- induced motor impairment (Rotarod, spontaneous locomotion, swim activity, muscle strength test), the MPTP-induced reduction in Tyrosine Hydroxylase (TH) levels (dopamine synthesis) in the substantia nigra and basal ganglia, the reduction of the synaptic marker synapstophysin, the inactivation of the growth factor kinase Akt/PKB and of the anti-apoptotic signaling molecule Bcl-2, and the increase of levels of the pro-inflammatory cytokine TNF-α. The results demonstrate that oxyntomodulin analogues show promise as a novel treatment of PD. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Cholecystokinin receptors: disparity between phosphoinositide breakdown and amylase releasing activity of CCK analogues in pancreas

    International Nuclear Information System (INIS)

    Lin, C.W.; Grant, D.; Bianchi, B.; Miller, T.; Witte, D.; Shue, Y.K.; Nadzan, A.

    1986-01-01

    Cholecystokinin (CCK) peptides are a family of hormones which also occur in brain. In pancreas CCK stimulates the release of amylase, a process that is dependent on the mobilization of intracellular Ca 2+ . Recent evidence suggests that inositol 1,4,5-trisphosphate, the breakdown product of phosphatidylinositol 4,5-bisphosphate, is responsible for the rise in intracellular Ca 2+ . Their laboratory has developed assays to study synthetic CCK analogues using radioligand binding, PI breakdown and amylase release. They have shown that there are good correlations among these three assay systems for the carboxy terminal fragments of CCK 8 . Recently, they have discovered synthetic analogues of CCK 4 that are full agonists in amylase release but are ineffective in causing PI breakdown. In particular, A-61576, Boc-5-amino-2-indolemethylene-pent-2-ene-1-oyl-Leu-Asp-Phe-NH 2 , is a full agonist in the amylase releasing assay, but is devoid of PI stimulating activity. A-61576 completely reverses the stimulation of PI response induced by CCK 8 , indicative of an antagonist. Since a mechanism other than the PI breakdown is responsible for amylase release by A-61576, they suggest that separate receptors are responsible for PI breakdown and amylase release

  4. Electromagnetic wave analogue of an electronic diode

    International Nuclear Information System (INIS)

    Shadrivov, Ilya V; Powell, David A; Kivshar, Yuri S; Fedotov, Vassili A; Zheludev, Nikolay I

    2011-01-01

    An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of rotation of the polarization state and is also a key component in optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by an extraordinarily strong nonlinear wave propagation effect in the same way as the electronic diode function is provided by the nonlinear current characteristic of a semiconductor junction. The effect exploited in this new electromagnetic diode is an intensity-dependent polarization change in an artificial chiral metamolecule. This microwave effect exceeds a similar optical effect previously observed in natural crystals by more than 12 orders of magnitude and a direction-dependent transmission that differs by a factor of 65.

  5. Reflective analogue optical link operating issues

    CERN Document Server

    Batten, Jeremy

    1996-01-01

    The proposed readout of analogue data from CMS tracker will use an optical fibre link. The choice of transmitter/receiver technology, however, has been the subject of intense research and development by the RD23 collaboration. One solution uses passive devices, multi-quantum well modulators, at the detector front end, and continuous wave driving lasers at the readout back end. This system has been tested at Imperial College. We report on the following: problems of noise associated with multimoded behaviour of a degraded laser; measurements of laser wavelength dependence on both drive current and temperature; and modulator reflectance dependence on laser wavelength. We extrapolate the findings to system issues, highlighting the degree of temperature control required of the driving laser.

  6. The gravitational analogue of the Witten effect

    International Nuclear Information System (INIS)

    Foda, O.

    1984-06-01

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP-violation, the Witten effect [a shift in the electric charge of a magnetic monopole due to CP-non-conservation] is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a theta R-tilde R term in the Lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed. (author)

  7. Gravitational analogue of the Witten effect

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O. (International Centre for Theoretical Physics, Trieste (Italy))

    1985-07-22

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP violation, the Witten effect (a shift in the electric charge of a magnetic monopole due to CP non-conservation) is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a thetaR tildeR term in the lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed.

  8. The gravitational analogue of the Witten effect

    International Nuclear Information System (INIS)

    Foda, O.

    1985-01-01

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP violation, the Witten effect (a shift in the electric charge of a magnetic monopole due to CP non-conservation) is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a thetaR tildeR term in the lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed. (orig.)

  9. Solution Processed PEDOT Analogues in Electrochemical Supercapacitors.

    Science.gov (United States)

    Österholm, Anna M; Ponder, James F; Kerszulis, Justin A; Reynolds, John R

    2016-06-01

    We have designed fully soluble ProDOTx-EDOTy copolymers that are electrochemically equivalent to electropolymerized PEDOT without using any surfactants or dispersants. We show that these copolymers can be incorporated as active layers in solution processed thin film supercapacitors to demonstrate capacitance, stability, and voltage similar to the values of those that use electrodeposited PEDOT as the active material with the added advantage of the possibility for large scale, high-throughput processing. These Type I supercapacitors provide exceptional cell voltages (up to 1.6 V), highly symmetrical charge/discharge behavior, promising long-term stability exceeding 50 000 charge/discharge cycles, as well as energy (4-18 Wh/kg) and power densities (0.8-3.3 kW/kg) that are comparable to those of electrochemically synthesized analogues.

  10. Synthesis of an Orthogonal Topological Analogue of Helicene

    DEFF Research Database (Denmark)

    Wixe, Torbjörn; Wallentin, Carl‐Johan; Johnson, Magnus T.

    2013-01-01

    The synthesis of an orthogonal topological pentamer analogue of helicene is presented. This analogue forms a tubular structure with its aromatic systems directed parallel to the axis of propagation, which creates a cavity with the potential to function as a host molecule. The synthetic strategy r...

  11. Uncertainties and credibility building of safety analyses. Natural analogues

    International Nuclear Information System (INIS)

    Laciok, A.

    2001-07-01

    The substance of natural analogues and their studies is defined as a complementary method to laboratory and in-situ experiments and modelling. The role of natural analogues in the processes of development of repositories is defined, mainly in performance assessment of repository system and communication with public. The criteria for identification of natural analogues which should be evaluated in the phase of initiation of new studies are specified. Review part of this report is divided to study of natural analogues and study of anthropogenic and industrial analogues. The main natural analogue studies performed in various countries, in different geological setting, with various aims are characterized. New results acquired in recently finished studies are included: Palmottu (2nd phase of project financed by European Commission), Oklo (results of research financed also by European Commission), Maqarin (3rd phase) and other information obtained from last meetings and workshops of NAWG. In view of the fact that programmes of development of deep repositories in Czech and Slovak Republics are interconnected, the natural analogues studies carried out in the Czech republic are incorporated in separate chapter - study of uranium accumulation in Tertiary clays at Ruprechtov site and study of degradation of natural glasses. In final part the areas of natural analogue studies as an integral part of development of deep geological repository are proposed along with characterization of broader context and aspects of realization of these studies (international cooperation, preparation and evaluation of procedures, communication with public). (author)

  12. Insulin analogues and severe hypoglycaemia in type 1 diabetes

    DEFF Research Database (Denmark)

    Kristensen, P L; Hansen, L S; Jespersen, M J

    2012-01-01

    The effect of insulin analogues on glycaemic control is well-documented, whereas the effect on avoidance of severe hypoglycaemia remains tentative. We studied the frequency of severe hypoglycaemia in unselected patients with type 1 diabetes treated with insulin analogues, human insulin, or mixed...

  13. Magnetic properties of Proxima Centauri b analogues

    Science.gov (United States)

    Zuluaga, Jorge I.; Bustamante, Sebastian

    2018-03-01

    The discovery of a planet around the closest star to our Sun, Proxima Centauri, represents a quantum leap in the testability of exoplanetary models. Unlike any other discovered exoplanet, models of Proxima b could be contrasted against near future telescopic observations and far future in-situ measurements. In this paper we aim at predicting the planetary radius and the magnetic properties (dynamo lifetime and magnetic dipole moment) of Proxima b analogues (solid planets with masses of ∼ 1 - 3M⊕ , rotation periods of several days and habitable conditions). For this purpose we build a grid of planetary models with a wide range of compositions and masses. For each point in the grid we run the planetary evolution model developed in Zuluaga et al. (2013). Our model assumes small orbital eccentricity, negligible tidal heating and earth-like radiogenic mantle elements abundances. We devise a statistical methodology to estimate the posterior distribution of the desired planetary properties assuming simple lprior distributions for the orbital inclination and bulk composition. Our model predicts that Proxima b would have a mass 1.3 ≤Mp ≤ 2.3M⊕ and a radius Rp =1.4-0.2+0.3R⊕ . In our simulations, most Proxima b analogues develop intrinsic dynamos that last for ≥4 Gyr (the estimated age of the host star). If alive, the dynamo of Proxima b have a dipole moment ℳdip >0.32÷2.9×2.3ℳdip , ⊕ . These results are not restricted to Proxima b but they also apply to earth-like planets having similar observed properties.

  14. Evolving a polymerase for hydrophobic base analogues.

    Science.gov (United States)

    Loakes, David; Gallego, José; Pinheiro, Vitor B; Kool, Eric T; Holliger, Philipp

    2009-10-21

    Hydrophobic base analogues (HBAs) have shown great promise for the expansion of the chemical and coding potential of nucleic acids but are generally poor polymerase substrates. While extensive synthetic efforts have yielded examples of HBAs with favorable substrate properties, their discovery has remained challenging. Here we describe a complementary strategy for improving HBA substrate properties by directed evolution of a dedicated polymerase using compartmentalized self-replication (CSR) with the archetypal HBA 5-nitroindole (d5NI) and its derivative 5-nitroindole-3-carboxamide (d5NIC) as selection substrates. Starting from a repertoire of chimeric polymerases generated by molecular breeding of DNA polymerase genes from the genus Thermus, we isolated a polymerase (5D4) with a generically enhanced ability to utilize HBAs. The selected polymerase. 5D4 was able to form and extend d5NI and d5NIC (d5NI(C)) self-pairs as well as d5NI(C) heteropairs with all four bases with efficiencies approaching, or exceeding, those of the cognate Watson-Crick pairs, despite significant distortions caused by the intercalation of the d5NI(C) heterocycles into the opposing strand base stack, as shown by nuclear magnetic resonance spectroscopy (NMR). Unlike Taq polymerase, 5D4 was also able to extend HBA pairs such as Pyrene: varphi (abasic site), d5NI: varphi, and isocarbostyril (ICS): 7-azaindole (7AI), allowed bypass of a chemically diverse spectrum of HBAs, and enabled PCR amplification with primers comprising multiple d5NI(C)-substitutions, while maintaining high levels of catalytic activity and fidelity. The selected polymerase 5D4 promises to expand the range of nucleobase analogues amenable to replication and should find numerous applications, including the synthesis and replication of nucleic acid polymers with expanded chemical and functional diversity.

  15. Natural analogues of nuclear waste glass corrosion

    International Nuclear Information System (INIS)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-01

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses

  16. MAQARIN natural analogue study: phase III

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, W R; Mazurek, M; Waber, H N [Univ. of Berne (Switzerland). Institutes of Geology, Mineralogy and Petrology, Rock-Water Interaction Group (GGWW); Arlinger, J; Erlandson, A C; Hallbeck, L; Pedersen, K [Goeteborg University (Sweden). Dept. of General and Marine Microbiology; Boehlmann, W; Fritz, P; Geyer, S; Geyer, W; Hanschman, G; Kopinke, F D; Poerschmann, J [Umweltforschungszentrum Leipzig-Halle (Germany); Chambers, A V; Haworth, A; Ilett, D; Linklater, C M; Tweed, C J [AEA Technology plc, Harwell (United Kingdom); Chenery, S R.N.; Kemp, S J; Milodowski, A E; Pearce, J M; Reeder, S; Rochelle, C A; Smith, B; Wetton, P D; Wragg, J [British Geological Survey, Keyworth (United Kingdom); Clark, I D [Univ. of Ottawa (Canada). Dept. of Geology; Hodginson, E; Hughes, C R [Univ. of Manchester (United Kingdom). Dept. of Earth Sciences; Hyslop, E K [British Geological Survey, Edinburgh (United Kingdom); Karlsson, F [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Khoury, H N; Salameh, E [Univ. of Jordan, Amman (Jordan); Lagerblad, B [Cement Institute, Stockholm (Sweden); Longworth, G [Univ. of Manchester (United Kingdom). Dept. of Geology; Pitty, A F [Private consultant, Norwich (United Kingdom); Savage, D [QuantiSci Ltd, Melton Mowbray (United Kingdom); Smellie, J A.T. [ed.; Conterra AB, Uppsala (Sweden)

    1998-12-01

    This report represents the conclusion to Phase III of the Maqarin Natural Analogue Study. The main thrust was to establish the origin and chemistry of the Western Springs hyper alkaline groundwaters (Na/K enriched Ca(OH){sub 2} type) and to study their interaction with rocks of different compositions, as natural analogues to key processes that might occur at an early stage within the `alkali disturbed zone` of cementitious repositories in different host rocks. Whilst earlier studies at Maqarin were very much site-specific and process-oriented, Phase III provided a regional perspective to the geological evolution of the Maqarin region. This was made possible by greater field access which allowed a more systematic structural and geomorphological study of the area. This has resulted in a greater understanding of the age and spatial relationships concerning formation of the cement zones through spontaneous combustion of the Bituminous Marls, and the subsequent formation of high pH groundwaters at the Eastern and Western Springs locations. At the Western Springs locality, hydrochemical and hydrogeological evaluation of new and published data (plus access to unpublished data), together with detailed mineralogical and geochemical studies, helped to clarify the very earliest stage of cement leachate/host rock interaction. The data were used also to test coupled flow/transport codes developed to assess the long-term evolution of a cementitious repository. Additional objectives addressed include: a) rock matrix diffusion, b) the occurrence and chemical controls on zeolite composition, e) the occurrence and chemical controls on clay stability, and d) the role of microbes, organics and colloids in trace element transport. The Maqarin site now provides a consistent picture explaining the origin of the hyperalkaline groundwaters, and is therefore a unique location for the examination of the mechanisms and processes associated with cementitious repositories. Application of these

  17. MAQARIN natural analogue study: phase III

    International Nuclear Information System (INIS)

    Alexander, W.R.; Mazurek, M.; Waber, H.N.; Arlinger, J.; Erlandson, A.C.; Hallbeck, L.; Pedersen, K.; Chambers, A.V.; Haworth, A.; Ilett, D.; Linklater, C.M.; Tweed, C.J.; Chenery, S.R.N.; Kemp, S.J.; Milodowski, A.E.; Pearce, J.M.; Reeder, S.; Rochelle, C.A.; Smith, B.; Wetton, P.D.; Wragg, J.; Clark, I.D.; Karlsson, F.; Khoury, H.N.; Salameh, E.; Lagerblad, B.; Longworth, G.; Savage, D.; Smellie, J.A.T.

    1998-12-01

    This report represents the conclusion to Phase III of the Maqarin Natural Analogue Study. The main thrust was to establish the origin and chemistry of the Western Springs hyper alkaline groundwaters (Na/K enriched Ca(OH) 2 type) and to study their interaction with rocks of different compositions, as natural analogues to key processes that might occur at an early stage within the 'alkali disturbed zone' of cementitious repositories in different host rocks. Whilst earlier studies at Maqarin were very much site-specific and process-oriented, Phase III provided a regional perspective to the geological evolution of the Maqarin region. This was made possible by greater field access which allowed a more systematic structural and geomorphological study of the area. This has resulted in a greater understanding of the age and spatial relationships concerning formation of the cement zones through spontaneous combustion of the Bituminous Marls, and the subsequent formation of high pH groundwaters at the Eastern and Western Springs locations. At the Western Springs locality, hydrochemical and hydrogeological evaluation of new and published data (plus access to unpublished data), together with detailed mineralogical and geochemical studies, helped to clarify the very earliest stage of cement leachate/host rock interaction. The data were used also to test coupled flow/transport codes developed to assess the long-term evolution of a cementitious repository. Additional objectives addressed include: a) rock matrix diffusion, b) the occurrence and chemical controls on zeolite composition, e) the occurrence and chemical controls on clay stability, and d) the role of microbes, organics and colloids in trace element transport. The Maqarin site now provides a consistent picture explaining the origin of the hyperalkaline groundwaters, and is therefore a unique location for the examination of the mechanisms and processes associated with cementitious repositories. Application of these

  18. Natural analogues in Posiva's Safety Case

    International Nuclear Information System (INIS)

    Marcos, Nuria; Seppaelae, T.

    2008-01-01

    The Safety Case is a broader concept than Performance Assessment that allows better the use of natural analogues and observations from nature to understand the behaviour of the system and the processes at the site. Natural analogues are mostly use to add confidence to the safety of geological disposal with respect to: Design (depth and multi-barrier system), Materials (long-term durability), and Processes (understanding the long-term behaviour/evolution of the system). Ice ages and erosion: largest boulders released and transported by ice during the most recent ice age are well below 20 m. 25 glacial cycles would be necessary to erode in this fashion 500 m of bedrock. During the last million years only about 8-9 glacial cycles are known to have occurred. Geosphere stability: Minor possibility of damaging earthquakes due to the geological position of the Olkiluoto site in the Fennoscandian Shield. Magnitudes of earthquakes historically and over the last 40 years have been less than 3 in the area next to Olkiluoto. Stability, U, and flow rates at Olkiluoto: Shallow ground-waters: Assuming a discharge flow rate (DFR) of about 200000 m"3/km"2/year, the average concentration of U in gw was 3.7 μg/L. At depth 375 m: Assuming a discharge flow rate of about 1680 m"3/km"2/year, the average concentration of U in gw was 0.21 μg/L. At depth 475 m: Discharge flow rate of about 730 m"3/km"2/year, the average concentration of U in gw was 0.04 μg/L

  19. MAQARIN natural analogue study: phase III

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, W R; Mazurek, M; Waber, H N [Univ. of Berne (Switzerland). Institutes of Geology, Mineralogy and Petrology, Rock-Water Interaction Group (GGWW); Arlinger, J; Erlandson, A C; Hallbeck, L; Pedersen, K [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology; Boehlmann, W; Fritz, P; Geyer, S; Geyer, W; Hanschman, G; Kopinke, F D; Poerschmann, J [Umweltforschungszentrum Leipzig-Halle (Germany); Chambers, A V; Haworth, A; Ilett, D; Linklater, C M; Tweed, C J [AEA Technology plc, Harwell (United Kingdom); Chenery, S R.N.; Kemp, S J; Milodowski, A E; Pearce, J M; Reeder, S; Rochelle, C A; Smith, B; Wetton, P D; Wragg, J [British Geological Survey, Keyworth (United Kingdom); Clark, I D [Univ. of Ottawa (Canada). Dept. of Geology; Hodginson, E; Hughes, C R [Univ. of Manchester (United Kingdom). Dept. of Earth Sciences; Hyslop, E K [British Geological Survey, Edinburgh (United Kingdom); Karlsson, F [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Khoury, H N; Salameh, E [Univ. of Jordan, Amman (Jordan); Lagerblad, B [Cement Inst., Stockholm (Sweden); Longworth, G [Univ. of Manchester (United Kingdom). Dept. of Geology; Pitty, A F [Private consultant, Norwich (United Kingdom); Savage, D [QuantiSci Ltd, Melton Mowbray (United Kingdom); Smellie, J A.T. [ed.; Conterra AB, Uppsala (Sweden)

    1998-12-01

    This report represents the conclusion to Phase III of the Maqarin Natural Analogue Study. The main thrust was to establish the origin and chemistry of the Western Springs hyper alkaline groundwaters (Na/K enriched Ca(OH){sub 2} type) and to study their interaction with rocks of different compositions, as natural analogues to key processes that might occur at an early stage within the `alkali disturbed zone` of cementitious repositories in different host rocks. Whilst earlier studies at Maqarin were very much site-specific and process-oriented, Phase III provided a regional perspective to the geological evolution of the Maqarin region. This was made possible by greater field access which allowed a more systematic structural and geomorphological study of the area. This has resulted in a greater understanding of the age and spatial relationships concerning formation of the cement zones through spontaneous combustion of the Bituminous Marls, and the subsequent formation of high pH groundwaters at the Eastern and Western Springs locations. At the Western Springs locality, hydrochemical and hydrogeological evaluation of new and published data (plus access to unpublished data), together with detailed mineralogical and geochemical studies, helped to clarify the very earliest stage of cement leachate/host rock interaction. The data were used also to test coupled flow/transport codes developed to assess the long-term evolution of a cementitious repository. Additional objectives addressed include: a) rock matrix diffusion, b) the occurrence and chemical controls on zeolite composition, e) the occurrence and chemical controls on clay stability, and d) the role of microbes, organics and colloids in trace element transport. The Maqarin site now provides a consistent picture explaining the origin of the hyperalkaline groundwaters, and is therefore a unique location for the examination of the mechanisms and processes associated with cementitious repositories. Application of these

  20. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  1. Ligand-regulated peptide aptamers.

    Science.gov (United States)

    Miller, Russell A

    2009-01-01

    The peptide aptamer approach employs high-throughput selection to identify members of a randomized peptide library displayed from a scaffold protein by virtue of their interaction with a target molecule. Extending this approach, we have developed a peptide aptamer scaffold protein that can impart small-molecule control over the aptamer-target interaction. This ligand-regulated peptide (LiRP) scaffold, consisting of the protein domains FKBP12, FRB, and GST, binds to the cell-permeable small-molecule rapamycin and the binding of this molecule can prevent the interaction of the randomizable linker region connecting FKBP12 with FRB. Here we present a detailed protocol for the creation of a peptide aptamer plasmid library, selection of peptide aptamers using the LiRP scaffold in a yeast two-hybrid system, and the screening of those peptide aptamers for a ligand-regulated interaction.

  2. 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...... 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....... 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...

  3. Analogue Hawking radiation from astrophysical black-hole accretion

    International Nuclear Information System (INIS)

    Das, Tapas K

    2004-01-01

    We show that spherical accretion onto astrophysical black holes can be considered as a natural example of an analogue system. We provide, for the first time, an exact analytical scheme for calculating the analogue Hawking temperature and surface gravity for general relativistic accretion onto astrophysical black holes. Our calculation may bridge the gap between the theory of transonic astrophysical accretion and the theory of analogue Hawking radiation. We show that the domination of the analogue Hawking temperature over the actual Hawking temperature may be a real astrophysical phenomenon, though observational tests of this fact will at best be difficult and at worst might prove to be impossible. We also discuss the possibilities of the emergence of analogue white holes around astrophysical black holes. Our calculation is general enough to accommodate accreting black holes with any mass

  4. Radioimmunoassay of 1-Deamino-8-D-Arginine Vasopressin and related peptides with special condsideration to their gastrointestinal absorption

    International Nuclear Information System (INIS)

    Lundin, S.

    1986-01-01

    A sensitive and specific radioimminoassy for 1-deamino-8-D-arginine vasopressin (DDAVP) was developed. Measurements of the analogue in extracted and non-extracted plasma yielded indentical results, the sensitivity was reduced with non-extracted samples. The assay was validated by correlating DDAVP blood levels to a biologic response (antidiuretic). Dilutions of plasma extracts containing DDAVP were parallel with the standard curve. Fractionations of extracted plasma DDAVP samples on HPLC revealed that immunoreactivity eluted as standard DDAVP. Prolonged infusion of DDAVP in rats did not alter pituitary secretion of oxytocin and vasopressin and urine osmolatity and volume changes were modest. DDAVP was absorbed from the gastrointestinal tract of humans, rats, rabbits and dogs in quantities sufficient to induce a biological response. Peak plasma concentrations were reached between 30-90 min after peptide administration. By the use of an in vitro model, the everted rat intestine, the transmucosal passage of a number of vasopressin analogues were tested. There was no clear-cut correlation between hydrophobicity and intestinal transport rates. Metabolic inhibitors and N/sub2/ did not decrease DDAVP transport. No transport maximum could be demonstrated over a 10/sup4/ fold concentration range. The distribution volume of /sup3/H-polyethyleneglycol was greater. then that of DDAVP in mucosal flakes. There was a close correlation between immunoassayable DDAVP levels and those found after HPLC analyses. It is proposed that DDAVP absorption occurs mainly by passive diffusion. The bioavailability of perorally ingested DDAVP in humans was about 1 percent. Minor amounts were excreted in urine

  5. Renal uptake and retention of radiolabeled somatostatin, bombesin, neurotensin, minigastrin and CCK analogues: species and gender differences

    Energy Technology Data Exchange (ETDEWEB)

    Melis, Marleen [Department of Nuclear Medicine, Erasmus MC Rotterdam, 3015 CE Rotterdam (Netherlands)], E-mail: m.melis@erasmusmc.nl; Krenning, Eric P.; Bernard, Bert F.; Visser, Monique de; Rolleman, Edgar; Jong, Marion de [Department of Nuclear Medicine, Erasmus MC Rotterdam, 3015 CE Rotterdam (Netherlands)

    2007-08-15

    Introduction: During therapy with radiolabeled peptides, the kidney is most often the critical organ. Newly developed peptides are evaluated preclinically in different animal models before their application in humans. In this study, the renal retention of several radiolabeled peptides was compared in male and female rats and mice. Methods: After intravenous injection of radiolabeled peptides [somatostatin, cholecystokinin (CCK), minigastrin, bombesin and neurotensin analogues], renal uptake was determined in both male and female Lewis rats and C57Bl mice. In addition, ex vivo autoradiography of renal sections was performed to localize accumulated radioactivity. Results: An equal distribution pattern of renal radioactivity was found for all peptides: high accumulation in the cortex, lower accumulation in the outer medulla and no radioactivity in the inner medulla of the kidneys. In both male rats and mice, an increasing renal uptake was found: [{sup 111}In-DTPA]CCK8<[{sup 111}In-DTPA-Pro{sup 1},Tyr{sup 4}]bombesin{approx}[{sup 111}In-DTPA] neurotensin<[{sup 111}In-DTPA]octreotide<<[{sup 111}In-DTPA]MG0. Renal uptake of [{sup 111}In-DTPA]octreotide in rats showed no gender difference, and renal radioactivity was about constant over time. In mice, however, renal uptake in females was significantly higher than that in males and decreased rapidly over time in both genders. Moreover, renal radioactivity in female mice injected with [{sup 111}In-DTPA]octreotide showed a different localization pattern. Conclusions: Regarding the renal uptake of different radiolabeled peptides, both species showed the same ranking order. Similar to findings in patients, rats showed comparable and constant renal retention of radioactivity in both genders, in contrast to mice. Therefore, rats appear to be the more favorable species for the study of the renal retention of radioactivity.

  6. Renal uptake and retention of radiolabeled somatostatin, bombesin, neurotensin, minigastrin and CCK analogues: species and gender differences

    International Nuclear Information System (INIS)

    Melis, Marleen; Krenning, Eric P.; Bernard, Bert F.; Visser, Monique de; Rolleman, Edgar; Jong, Marion de

    2007-01-01

    Introduction: During therapy with radiolabeled peptides, the kidney is most often the critical organ. Newly developed peptides are evaluated preclinically in different animal models before their application in humans. In this study, the renal retention of several radiolabeled peptides was compared in male and female rats and mice. Methods: After intravenous injection of radiolabeled peptides [somatostatin, cholecystokinin (CCK), minigastrin, bombesin and neurotensin analogues], renal uptake was determined in both male and female Lewis rats and C57Bl mice. In addition, ex vivo autoradiography of renal sections was performed to localize accumulated radioactivity. Results: An equal distribution pattern of renal radioactivity was found for all peptides: high accumulation in the cortex, lower accumulation in the outer medulla and no radioactivity in the inner medulla of the kidneys. In both male rats and mice, an increasing renal uptake was found: [ 111 In-DTPA]CCK8 111 In-DTPA-Pro 1 ,Tyr 4 ]bombesin∼[ 111 In-DTPA] neurotensin 111 In-DTPA]octreotide 111 In-DTPA]MG0. Renal uptake of [ 111 In-DTPA]octreotide in rats showed no gender difference, and renal radioactivity was about constant over time. In mice, however, renal uptake in females was significantly higher than that in males and decreased rapidly over time in both genders. Moreover, renal radioactivity in female mice injected with [ 111 In-DTPA]octreotide showed a different localization pattern. Conclusions: Regarding the renal uptake of different radiolabeled peptides, both species showed the same ranking order. Similar to findings in patients, rats showed comparable and constant renal retention of radioactivity in both genders, in contrast to mice. Therefore, rats appear to be the more favorable species for the study of the renal retention of radioactivity

  7. Streamlined Total Synthesis of Trioxacarcins and Its Application to the Design, Synthesis, and Biological Evaluation of Analogues Thereof. Discovery of Simpler Designed and Potent Trioxacarcin Analogues.

    Science.gov (United States)

    Nicolaou, K C; Chen, Pengxi; Zhu, Shugao; Cai, Quan; Erande, Rohan D; Li, Ruofan; Sun, Hongbao; Pulukuri, Kiran Kumar; Rigol, Stephan; Aujay, Monette; Sandoval, Joseph; Gavrilyuk, Julia

    2017-11-01

    A streamlined total synthesis of the naturally occurring antitumor agents trioxacarcins is described, along with its application to the construction of a series of designed analogues of these complex natural products. Biological evaluation of the synthesized compounds revealed a number of highly potent, and yet structurally simpler, compounds that are effective against certain cancer cell lines, including a drug-resistant line. A novel one-step synthesis of anthraquinones and chloro anthraquinones from simple ketone precursors and phenylselenyl chloride is also described. The reported work, featuring novel chemistry and cascade reactions, has potential applications in cancer therapy, including targeted approaches as in antibody-drug conjugates.

  8. B-Type Natriuretic Peptide: From Posttranslational Processing to Clinical Measurement

    DEFF Research Database (Denmark)

    Goetze, Jens P

    2012-01-01

    BACKGROUND:Plasma cardiac natriuretic peptides and peptide fragments from their molecular precursors are markers of heart disease. Clinical studies have defined the current diagnostic utility of these markers, whereas biochemical elucidation of peptide structure and posttranslational processing has...... revealed new plasma peptide forms of potential clinical use.CONTENT:Natriuretic propeptide structures undergo variable degrees of endo- and exoproteolytic cleavages as well as amino acid modifications, which leave the plasma phase of the peptides highly heterogeneous and dependent on cardiac......-atrial natriuretic peptide and pro-B-type natriuretic peptide are useful plasma markers in heart failure. New data have defined cardiac myocytes as competent endocrine cells in posttranslational processing and cellular secretion....

  9. Analogues of uracil nucleosides with intrinsic fluorescence (NIF-analogues): synthesis and photophysical properties.

    Science.gov (United States)

    Segal, Meirav; Fischer, Bilha

    2012-02-28

    Uridine cannot be utilized as fluorescent probe due to its extremely low quantum yield. For improving the uracil fluorescence characteristics we extended the natural chromophore at the C5 position by coupling substituted aromatic rings directly or via an alkenyl or alkynyl linker to create fluorophores. Extension of the uracil base was achieved by treating 5-I-uridine with the appropriate boronic acid under the Suzuki coupling conditions. Analogues containing an alkynyl linker were obtained from 5-I-uridine and the suitable boronic acid in a Sonogashira coupling reaction. The uracil fluorescent analogues proposed here were designed to satisfy the following requirements: a minimal chemical modification at a position not involved in base-pairing, resulting in relatively long absorption and emission wavelengths and high quantum yield. 5-((4-Methoxy-phenyl)-trans-vinyl)-2'-deoxy-uridine, 6b, was found to be a promising fluorescent probe. Probe 6b exhibits a quantum yield that is 3000-fold larger than that of the natural chromophore (Φ 0.12), maximum emission (478 nm) which is 170 nm red shifted as compared to uridine, and a Stokes shift of 143 nm. In addition, since probe 6b adopts the anti conformation and S sugar puckering favored by B-DNA, it makes a promising nucleoside analogue to be incorporated in an oligonucleotide probe for detection of genetic material.

  10. Analogue to Digital and Digital to Analogue (AD/DA) Conversion Techniques: An Overview

    CERN Multimedia

    CERN. Geneva

    2002-01-01

    The basic ideas behind modern Analogue to Digital and Digital to Analogue (AD/DA) conversion methods will be introduced: a general view of the importance of these devices will be given, along with the digital representation of time-varying, real-world analogue signals. Some CERN applications will be outlined. The variety of conversion methods, their limitations, error sources and measurement methods will form the major part of this presentation. A review of the technological progress in this field over the last 30 years will be presented, concluding with the present 'state of the art' and a quick look at what is just around the corner. This Technical Training Seminar is in the framework of the FEED-2002 Lecture Series, and it is a prerequisite to attending to any of the FEED-2002 Terms. FEED-2002 is a two-term course that will review the techniques dealing with closed loop systems, focussing on time-invariant linear systems. (free attendance, no registration required) More information on the FEED-2002 ...

  11. Toxicity Assessments of Chalcone and Some Synthetic Chalcone Analogues in a Zebrafish Model

    Directory of Open Access Journals (Sweden)

    Ya-Ting Lee

    2014-01-01

    Full Text Available The aim of this study was to investigate the in vivo toxicities of some novel synthetic chalcones. Chalcone and four chalcone analogues 1a–d were evaluated using zebrafish embryos following antibody staining to visualize their morphological changes and muscle fiber alignment. Results showed that embryos treated with 3'-hydroxychalcone (compound 1b displayed a high percentage of muscle defects (96.6%, especially myofibril misalignment. Ultrastructural analysis revealed that compound 1b-treated embryos displayed many muscle defect phenotypes, including breakage and collapse of myofibrils, reduced cell numbers, and disorganized thick (myosin and thin (actin filaments. Taken together, our results provide in vivo evidence of the myotoxic effects of the synthesized chalcone analogues on developing zebrafish embryos.

  12. 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.

  13. Radiolabelled peptides: New radiopharmaceuticals for targeted therapy

    International Nuclear Information System (INIS)

    Chinol, M.

    2001-01-01

    Radiolabelled peptides have been the focus of an increasing interest by the nuclear medicine community within the last few years. This has mainly been due to successful development of one of these peptides, somatostatin, as a tool to visualise various pathologic conditions known to express a high number of somatostatin receptors. Somatostatin receptors have been identified in different tumours such as neuroendocrine tumours, tumours of the central nervous system, breast, lung and lymphatic tissue. These observations served as the biomolecular basis for the clinical use of radiolabelled somatostatin analogs, which are at present of great interest for diagnostic and therapeutic applications. A promising somatostatin analogue, DOTA-D-Phe 1 -Ty 3 -octreotide, named DOTATOC, has shown favourable biodistribution and high affinity binding to SSTR2 and SSTR5, high hydrophilicity and ease of labelling and stability with 111 In and 90 Y. A clinical trial aimed at evaluating the biodistribution and dosimetry of DOTATOC radiolabelled with 111 In, in anticipation of therapy trials with 90 Y-DOTATOC in patients was undertaken. 111 In-DOTATOC showed favourable pharmacokinetics (fast blood clearance and urinary excretion) and biodistribution, and high affinity to tumours expressing somatostatin receptors (thus, a high residence time in tumour). These results are promising for therapy trials with 90 Y-DOTAOC, for which radiation dosimetry appears acceptable for normal organs (including the red marrow). Moreover, labelling conditions of DOTATOC with 90 Y has been optimised in order to achieve labelling yields of more than 98% and specific activities of greater than 60 GBq (1.6 Ci)/μmol. (author)

  14. Regulation of the mesolimbic dopamine circuit by feeding peptides.

    Science.gov (United States)

    Liu, S; Borgland, S L

    2015-03-19

    Polypeptides produced in the gastrointestinal tract, stomach, adipocytes, pancreas and brain that influence food intake are referred to as 'feeding-related' peptides. Most peptides that influence feeding exert an inhibitory effect (anorexigenic peptides). In contrast, only a few exert a stimulating effect (orexigenic peptides), such as ghrelin. Homeostatic feeding refers to when food consumed matches energy deficits. However, in western society where access to palatable energy-dense food is nearly unlimited, food is mostly consumed for non-homeostatic reasons. Emerging evidence implicates the mesocorticolimbic circuitry, including dopamine neurons of the ventral tegmental area (VTA), as a key substrate for non-homeostatic feeding. VTA dopamine neurons encode cues that predict rewards and phasic release of dopamine in the ventral striatum motivates animals to forage for food. To elucidate how feeding-related peptides regulate reward pathways is of importance to reveal the mechanisms underlying non-homeostatic or hedonic feeding. Here, we review the current knowledge of how anorexigenic peptides and orexigenic peptides act within the VTA. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  15. The Greenland Analogue Project. Yearly Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    A deep geological repository for spent nuclear fuel needs to be designed to keep used nuclear fuel isolated from mankind and the environment for a million years. Within this time frame glacial conditions are expected in regions that have been glaciated in the past two to ten million years. Climate induced changes such as the growth of ice sheets and permafrost will influence and alter the ground surface and subsurface environment, including its hydrology, which may impact repository safety. Glaciation impact assessments have to-date used over-simplified models and conservative assumptions, for example in the representation of ice sheet hydrology, that do not reflect the complexity of natural systems and processes. This is largely due to lack of direct observations of such processes from existing ice sheets, which if more readily available could help reduce uncertainties and provide a strong scientific basis for the treatment of glacial impacts in safety assessments. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with glacial cycles and their impact on the long-term performance of deep geological repositories for spent nuclear fuel will be significantly improved by studying a modern analogue. To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of

  16. The Greenland Analogue Project. Yearly Report 2009

    International Nuclear Information System (INIS)

    2010-12-01

    A deep geological repository for spent nuclear fuel needs to be designed to keep used nuclear fuel isolated from mankind and the environment for a million years. Within this time frame glacial conditions are expected in regions that have been glaciated in the past two to ten million years. Climate induced changes such as the growth of ice sheets and permafrost will influence and alter the ground surface and subsurface environment, including its hydrology, which may impact repository safety. Glaciation impact assessments have to-date used over-simplified models and conservative assumptions, for example in the representation of ice sheet hydrology, that do not reflect the complexity of natural systems and processes. This is largely due to lack of direct observations of such processes from existing ice sheets, which if more readily available could help reduce uncertainties and provide a strong scientific basis for the treatment of glacial impacts in safety assessments. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with glacial cycles and their impact on the long-term performance of deep geological repositories for spent nuclear fuel will be significantly improved by studying a modern analogue. To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of

  17. De novo sequencing of two novel peptides homologous to calcitonin-like peptides, from skin secretion of the Chinese Frog, Odorrana schmackeri

    Directory of Open Access Journals (Sweden)

    Geisa P.C. Evaristo

    2015-09-01

    Full Text Available An MS/MS based analytical strategy was followed to solve the complete sequence of two new peptides from frog (Odorrana schmackeri skin secretion. This involved reduction and alkylation with two different alkylating agents followed by high resolution tandem mass spectrometry. De novo sequencing was achieved by complementary CID and ETD fragmentations of full-length peptides and of selected tryptic fragments. Heavy and light isotope dimethyl labeling assisted with annotation of sequence ion series. The identified primary structures are GCD[I/L]STCATHN[I/L]VNE[I/L]NKFDKSKPSSGGVGPESP-NH2 and SCNLSTCATHNLVNELNKFDKSKPSSGGVGPESF-NH2, i.e. two carboxyamidated 34 residue peptides with an aminoterminal intramolecular ring structure formed by a disulfide bridge between Cys2 and Cys7. Edman degradation analysis of the second peptide positively confirmed the exact sequence, resolving I/L discriminations. Both peptide sequences are novel and share homology with calcitonin, calcitonin gene related peptide (CGRP and adrenomedullin from other vertebrates. Detailed sequence analysis as well as the 34 residue length of both O. schmackeri peptides, suggest they do not fully qualify as either calcitonins (32 residues or CGRPs (37 amino acids and may justify their classification in a novel peptide family within the calcitonin gene related peptide superfamily. Smooth muscle contractility assays with synthetic replicas of the S–S linked peptides on rat tail artery, uterus, bladder and ileum did not reveal myotropic activity.

  18. A compendium of cyclic sugar amino acids and their carbocyclic and heterocyclic nitrogen analogues.

    Science.gov (United States)

    Risseeuw, Martijn; Overhand, Mark; Fleet, George W J; Simone, Michela I

    2013-10-01

    This compendium focuses on functionalised sugar amino acids (SAAs) and their 3- to 6-membered nitrogen heterocyclic and carbocyclic analogues. The main benefit of using SAAs and their related nitrogen and carbon congeners in the production of peptidomimetics and glycomimetics is that their properties can be readily altered via modification of their ring size, chemical manipulation of their numerous functional groups and fine-tuning of the stereochemical arrangement of their ring substituents. These building blocks provide access to hydrophilic and hydrophobic peptide isosteres whose physical properties allow entry to a region of chemotherapeutic space which is still under-explored by medicinal chemists. These building blocks are also important in providing amino acids whose inherent conformational bias leads to predisposition to secondary structure upon oligomerisation in relatively short sequences. These foldamers, particularly those containing ω-amino acids, provide an additional opportunity to expand access to the control of structures by artificial peptides. The synthesis and biological evaluation of these building blocks in glycomimetics and peptidomimetics systems keep expanding the reach of the glycosciences to the medical sciences, provide a greater outlook onto the wide range of cellular functions of saccharides and their derivatives involved and greater insight into the nature of oligosaccharide and protein folding.

  19. Separation of multiphosphorylated peptide isomers by hydrophilic interaction chromatography on an aminopropyl phase.

    Science.gov (United States)

    Singer, David; Kuhlmann, Julia; Muschket, Matthias; Hoffmann, Ralf

    2010-08-01

    The separation of isomeric phosphorylated peptides is challenging and often impossible for multiphosphorylated isomers using chromatographic and capillary electrophoretic methods. In this study we investigated the separation of a set of single-, double-, and triple-phosphorylated peptides (corresponding to the human tau protein) by ion-pair reversed-phase chromatography (IP-RPC) and hydrophilic interaction chromatography (HILIC). In HILIC both hydroxyl and aminopropyl stationary phases were tested with aqueous acetonitrile in order to assess their separation efficiency. The hydroxyl phase separated the phosphopeptides very well from the unphosphorylated analogue, while on the aminopropyl phase even isomeric phosphopeptides attained baseline separation. Thus, up to seven phosphorylated versions of a given tau domain were separated. Furthermore, the low concentration of an acidic ammonium formate buffer allowed an online analysis with electrospray ionization tandem mass spectrometry (ESI-MS/MS) to be conducted, enabling peptide sequencing and identification of phosphorylation sites.

  20. Native copper as a natural analogue for copper canisters

    International Nuclear Information System (INIS)

    Marcos, N.

    1989-12-01

    This paper discusses the occurrence of native copper as found in geological formations as a stability analogue of copper canisters that are planned to be used for the disposal of spent nuclear fuel in the Finnish bedrock. A summary of several publications on native copper occurrences is presented. The present geochemical and geohydrological conditions in which copper is met with in its metallic state show that metallic copper is stable in a wide range of temperatures. At low temperatures native copper is found to be stable where groundwater has moderate pH (about 7), low Eh (< +100 mV), and low total dissolved solids, especially chloride. Microscopical and microanalytical studies were carried out on a dozen of rock samples containing native copper. The results reveal that the metal shows no significant alteration. Only the surface of copper grains is locally coated. In the oldest samples there exist small corrosion cracks; the age of the oldest samples is over 1,000 million years. A review of several Finnish groundwater studies suggests that there are places in Finland where the geohydrological conditions are favourable for native copper stability. (orig.)

  1. Interactions of cisplatin analogues with lysozyme: a comparative analysis.

    Science.gov (United States)

    Ferraro, Giarita; De Benedictis, Ilaria; Malfitano, Annamaria; Morelli, Giancarlo; Novellino, Ettore; Marasco, Daniela

    2017-10-01

    The biophysical characterization of drug binding to proteins plays a key role in structural biology and in the discovery and optimization of drug discovery processes. The search for optimal combinations of biophysical techniques that can correctly and efficiently identify and quantify binding of metal-based drugs to their final target is challenging, due to the physicochemical properties of these agents. Different cisplatin derivatives have shown different citotoxicities in most common cancer lines, suggesting that they exert their biological activity via different mechanisms of action. Here we carried out a comparative analysis, by studying the behaviours of three Pt-compounds under the same experimental conditions and binding assays to properly deepen the determinants of the different MAOs. Indeed we compared the results obtained using surface plasmon resonance, isothermal titration calorimetry, fluorescence spectroscopy and thermal shift assays based on circular dichroism experiments in the characterization of the formation of adducts obtained upon reaction of cisplatin, carboplatin and iodinated analogue of cisplatin, cis-Pt (NH 3 ) 2 I 2 , with the model protein hen egg white lysozyme, both at neutral and acid pHs. Further we reasoned on the applicability of employed techniques for the study the thermodynamics and kinetics of the reaction of a metallodrug with a protein and to reveal which information can be obtained using a combination of these analyses. Data were discussed on the light of the existing structural data collected on the platinated protein.

  2. Use of analogues to build technologists' confidence: NAnet

    International Nuclear Information System (INIS)

    Noseck, Ulrich

    2008-01-01

    The relevance of analogues to radioactive waste management stems from the long timescales that have to be considered. Periods up to a million or more years into the future need to be considered and these are beyond experimental investigation and human experience. Within the last years the term 'Natural Analogue' has got a much wider meaning and includes man-made analogues as well. The role of natural analogues in the safety case depends amongst others on the time scale to be covered. Therefore, it is useful to classify them by the time period addressed in the study. Here it is referred to: industrial analogues which started earliest 150 years ago, archaeological analogues, which cover time frames between the past 10 000 and 150 years, and geological analogues, which usually cover time frames of more than 10 000 years and in most cases more than million years. The current interest in analogues in different countries is reflected by several recent review projects with emphasis on the application of natural analogue study results in performance assessment. The most recent international review was performed within the 5. EURATOM Framework of the EC by the NAnet project, a network on the review of natural analogue studies with emphasis on the application of analogues in long-term safety assessment and communication. The overall aim of the NAnet project was to review the past and present use and understanding of natural analogues, and to make recommendations for their future use. The project covered 'traditional' natural analogue studies, such as large-scale investigations of radionuclide transport around uranium ore bodies, and process or mechanistic analogue studies such as those examining natural glass and bentonite clay stability. To complete the picture, a restricted range of other studies of natural systems which employ a similar philosophy to analogues was also included in the scope. These included studies which have examined radionuclide transport and retardation

  3. Single-cell resolution imaging of retinal ganglion cell apoptosis in vivo using a cell-penetrating caspase-activatable peptide probe.

    Directory of Open Access Journals (Sweden)

    Xudong Qiu

    Full Text Available Peptide probes for imaging retinal ganglion cell (RGC apoptosis consist of a cell-penetrating peptide targeting moiety and a fluorophore-quencher pair flanking an effector caspase consensus sequence. Using ex vivo fluorescence imaging, we previously validated the capacity of these probes to identify apoptotic RGCs in cell culture and in an in vivo rat model of N-methyl- D-aspartate (NMDA-induced neurotoxicity. Herein, using TcapQ488, a new probe designed and synthesized for compatibility with clinically-relevant imaging instruments, and real time imaging of a live rat RGC degeneration model, we fully characterized time- and dose-dependent probe activation, signal-to-noise ratios, and probe safety profiles in vivo. Adult rats received intravitreal injections of four NMDA concentrations followed by varying TcapQ488 doses. Fluorescence fundus imaging was performed sequentially in vivo using a confocal scanning laser ophthalmoscope and individual RGCs displaying activated probe were counted and analyzed. Rats also underwent electroretinography following intravitreal injection of probe. In vivo fluorescence fundus imaging revealed distinct single-cell probe activation as an indicator of RGC apoptosis induced by intravitreal NMDA injection that corresponded to the identical cells observed in retinal flat mounts of the same eye. Peak activation of probe in vivo was detected 12 hours post probe injection. Detectable fluorescent RGCs increased with increasing NMDA concentration; sensitivity of detection generally increased with increasing TcapQ488 dose until saturating at 0.387 nmol. Electroretinography following intravitreal injections of TcapQ488 showed no significant difference compared with control injections. We optimized the signal-to-noise ratio of a caspase-activatable cell penetrating peptide probe for quantitative non-invasive detection of RGC apoptosis in vivo. Full characterization of probe performance in this setting creates an important in

  4. Skin Delivery of EGCG and Silibinin: Potential of Peptide Dendrimers for Enhanced Skin Permeation and Deposition.

    Science.gov (United States)

    Shetty, Pallavi Krishna; Manikkath, Jyothsna; Tupally, Karnaker; Kokil, Ganesh; Hegde, Aswathi R; Raut, Sushil Y; Parekh, Harendra S; Mutalik, Srinivas

    2017-08-01

    The aim of the present study was to evaluate the ability of the peptide dendrimers to facilitate transdermal delivery of antioxidants, silibinin, and epigallocatechin-3-gallate (EGCG). Drug-peptide dendrimer complexes were prepared and evaluated for their ability to permeate across the skin. The data revealed the ready formation of complexes between drug and peptide dendrimer in a molar ratio of 1:1. In vitro permeation studies using excised rat skin and drug-peptide dendrimer complexes showed highest values for cumulative drug permeation at the end of 12 h (Q 12 ), with corresponding permeability coefficient (Kp) and enhancement ratio values also determined at this time point. With silibinin, 3.96-, 1.81-, and 1.06-fold increase in skin permeation was observed from silibinin-peptide dendrimer complex, simultaneous application of silibinin + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. With EGCG, 9.82-, 2.04-, and 1.72-fold increase in skin permeation was observed from EGCG-peptide dendrimer complex, simultaneous application of EGCG + peptide dendrimer, and pretreatment of skin with peptide dendrimer, respectively, in comparison with passive diffusion. The present study demonstrates the application of peptide dendrimers in effectively delivering antioxidants such as EGCG and silibinin into the skin, thus offering the potential to provide antioxidant effects when delivered via appropriately formulated topical preparations.

  5. Feasibility and availability of 68Ga-labelled peptides

    International Nuclear Information System (INIS)

    Decristoforo, Clemens; Pickett, Roger D.; Verbruggen, Alfons

    2012-01-01

    68 Ga has attracted tremendous interest as a radionuclide for PET based on its suitable half-life of 68 min, high positron emission yield and ready availability from 68 Ge/ 68 Ga generators, making it independent of cyclotron production. 68 Ga-labelled DOTA-conjugated somatostatin analogues, including DOTA-TOC, DOTA-TATE and DOTA-NOC, have driven the development of technologies to provide such radiopharmaceuticals for clinical applications mainly in the diagnosis of somatostatin receptor-expressing tumours. We summarize the issues determining the feasibility and availability of 68 Ga-labelled peptides, including generator technology, 68 Ga generator eluate postprocessing methods, radiolabelling, automation and peptide developments, and also quality assurance and regulatory aspects. 68 Ge/ 68 Ga generators based on SnO 2 , TiO 2 or organic matrices are today routinely supplied to nuclear medicine departments, and a variety of automated systems for postprocessing and radiolabelling have been developed. New developments include improved chelators for 68 Ga that could open new ways to utilize this technology. Challenges and limitations in the on-site preparation and use of 68 Ga-labelled peptides outside the marketing authorization track are also discussed. (orig.)

  6. Feasibility and availability of {sup 68}Ga-labelled peptides

    Energy Technology Data Exchange (ETDEWEB)

    Decristoforo, Clemens [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); European Directorate of Quality of Medicines, Group 14, Radioactive Compounds, The European Pharmacopeia, Strasbourg (France); Pickett, Roger D. [GE Healthcare, Little Chalfont (United Kingdom); European Directorate of Quality of Medicines, Group 14, Radioactive Compounds, The European Pharmacopeia, Strasbourg (France); Verbruggen, Alfons [University of Leuven, Laboratory of Radiopharmacy, Department of Pharmaceutical Sciences, Leuven (Belgium); European Directorate of Quality of Medicines, Group 14, Radioactive Compounds, The European Pharmacopeia, Strasbourg (France)

    2012-02-15

    {sup 68}Ga has attracted tremendous interest as a radionuclide for PET based on its suitable half-life of 68 min, high positron emission yield and ready availability from {sup 68}Ge/{sup 68}Ga generators, making it independent of cyclotron production. {sup 68}Ga-labelled DOTA-conjugated somatostatin analogues, including DOTA-TOC, DOTA-TATE and DOTA-NOC, have driven the development of technologies to provide such radiopharmaceuticals for clinical applications mainly in the diagnosis of somatostatin receptor-expressing tumours. We summarize the issues determining the feasibility and availability of {sup 68}Ga-labelled peptides, including generator technology, {sup 68}Ga generator eluate postprocessing methods, radiolabelling, automation and peptide developments, and also quality assurance and regulatory aspects. {sup 68}Ge/{sup 68}Ga generators based on SnO{sub 2}, TiO{sub 2} or organic matrices are today routinely supplied to nuclear medicine departments, and a variety of automated systems for postprocessing and radiolabelling have been developed. New developments include improved chelators for {sup 68}Ga that could open new ways to utilize this technology. Challenges and limitations in the on-site preparation and use of {sup 68}Ga-labelled peptides outside the marketing authorization track are also discussed. (orig.)

  7. Feasibility and availability of ⁶⁸Ga-labelled peptides.

    Science.gov (United States)

    Decristoforo, Clemens; Pickett, Roger D; Verbruggen, Alfons

    2012-02-01

    (68)Ga has attracted tremendous interest as a radionuclide for PET based on its suitable half-life of 68 min, high positron emission yield and ready availability from (68)Ge/(68)Ga generators, making it independent of cyclotron production. (68)Ga-labelled DOTA-conjugated somatostatin analogues, including DOTA-TOC, DOTA-TATE and DOTA-NOC, have driven the development of technologies to provide such radiopharmaceuticals for clinical applications mainly in the diagnosis of somatostatin receptor-expressing tumours. We summarize the issues determining the feasibility and availability of (68)Ga-labelled peptides, including generator technology, (68)Ga generator eluate postprocessing methods, radiolabelling, automation and peptide developments, and also quality assurance and regulatory aspects. (68)Ge/(68)Ga generators based on SnO(2), TiO(2) or organic matrices are today routinely supplied to nuclear medicine departments, and a variety of automated systems for postprocessing and radiolabelling have been developed. New developments include improved chelators for (68)Ga that could open new ways to utilize this technology. Challenges and limitations in the on-site preparation and use of (68)Ga-labelled peptides outside the marketing authorization track are also discussed.

  8. Therapeutic peptides for cancer therapy. Part II - cell cycle inhibitory peptides and apoptosis-inducing peptides.

    Science.gov (United States)

    Raucher, Drazen; Moktan, Shama; Massodi, Iqbal; Bidwell, Gene L

    2009-10-01

    Therapeutic peptides have great potential as anticancer agents owing to their ease of rational design and target specificity. However, their utility in vivo is limited by low stability and poor tumor penetration. The authors review the development of peptide inhibitors with potential for cancer therapy. Peptides that arrest the cell cycle by mimicking CDK inhibitors or induce apoptosis directly are discussed. The authors searched Medline for articles concerning the development of therapeutic peptides and their delivery. Inhibition of cancer cell proliferation directly using peptides that arrest the cell cycle or induce apoptosis is a promising strategy. Peptides can be designed that interact very specifically with cyclins and/or cyclin-dependent kinases and with members of apoptotic cascades. Use of these peptides is not limited by their design, as a rational approach to peptide design is much less challenging than the design of small molecule inhibitors of specific protein-protein interactions. However, the limitations of peptide therapy lie in the poor pharmacokinetic properties of these large, often charged molecules. Therefore, overcoming the drug delivery hurdles could open the door for effective peptide therapy, thus making an entirely new class of molecules useful as anticancer drugs.

  9. Absorption kinetics and action profiles of subcutaneously administered insulin analogues (AspB9GluB27, AspB10, AspB28) in healthy subjects.

    Science.gov (United States)

    Kang, S; Brange, J; Burch, A; Vølund, A; Owens, D R

    1991-11-01

    The subcutaneous absorption and resulting changes in plasma insulin or analogue, glucose, C-peptide, and blood intermediary metabolite concentrations after subcutaneous bolus injection of three soluble human insulin analogues (AspB9GluB27, monomeric; AspB28, mixture of monomers and dimers; and AspB10, dimeric) and soluble human insulin were evaluated. Fasting healthy male volunteers (n = 7) were studied on five occasions 1 wk apart randomly receiving 0.6 nmol.kg-1 s.c. 125I-labeled AspB10 or soluble human insulin (Novolin R, Novo, Copenhagen); 1st study and 0.6 nmol.kg-1 s.c. 125I-labeled AspB28, AspB9GluB27 or soluble human insulin (2nd study). Residual radioactivity at the injection site was measured over 8 h with frequent venous sampling for plasma immunoreactive insulin or analogue, glucose, C-peptide, and blood intermediary metabolite concentrations. The three analogues were absorbed 2-3 times faster than human insulin. The mean +/- SE time to 50% residual radioactivity was 94 +/- 6 min for AspB10 compared with 184 +/- 10 min for human insulin (P less than 0.001), 83 +/- 8 min for AspB28 (P less than 0.005), and 63 +/- 9 min for AspB9GluB27 (P less than 0.001) compared with 182 +/- 21 min for human insulin. delta Peak plasma insulin analogue levels were significantly higher after each analogue than after human insulin (P less than 0.005). With all three analogues, the mean hypoglycemic nadir occurred earlier at 61-65 min postinjection compared with 201-210 min for the reference human insulins (P less than 0.005). The magnitude of the hypoglycemic nadir was greater after AspB9GluB27 (P less than 0.05) and AspB28 (P less than 0.001) compared with human insulin. There was a significantly faster onset and offset of responses in C-peptide and intermediary metabolite levels after the analogues than after human insulin (P less than 0.05). The rapid absorption and biological actions of these analogues offer potential therapeutic advantages over the current short

  10. A Low-cost Multi-channel Analogue Signal Generator

    CERN Document Server

    Müller, F; The ATLAS collaboration; Shen, W; Stamen, R

    2009-01-01

    A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The signal generator was successfully used as independent test bed for the ATLAS Level-1 Trigger Pre-Processor, providing up to 16 analogue signals.

  11. Conjugate dynamical systems: classical analogue of the quantum energy translation

    International Nuclear Information System (INIS)

    Torres-Vega, Gabino

    2012-01-01

    An aspect of quantum mechanics that has not been fully understood is the energy shift generated by the time operator. In this study, we introduce the use of the eigensurfaces of dynamical variables and commutators in classical mechanics to study the classical analogue of the quantum translation of energy. We determine that there is a conjugate dynamical system that is conjugate to Hamilton's equations of motion, and then we generate the analogue of the time operator and use it in the translation of points along the energy direction, i.e. the classical analogue of the Pauli theorem. The theory is illustrated with a nonlinear oscillator model. (paper)

  12. UK Natural Analogue Coordinating Group: fourth annual report

    International Nuclear Information System (INIS)

    Read, D.; Hooker, P.J.

    1992-01-01

    HMIP has a research programme investigating some naturally radioactive sites as geochemical analogues of radionuclide migration. All of the analogue sites under investigation, both in the U.K. and overseas, are located where elevated uranium concentrations occur naturally. Coordination of the programme is achieved through the UK Natural Analogue Co-ordinating Group (NACG) which has met three times in this reporting period. The NACG is steered by the British Geological Survey. Its purpose is to ensure that the different research projects have an integrated function aimed at increasing our understanding of natural geochemical processes. Effort is also being expended in testing research models which may be used in such assessments. (author)

  13. High-resolution mass spectrometry driven discovery of peptidic danger signals in insect immunity.

    Directory of Open Access Journals (Sweden)

    Arton Berisha

    Full Text Available The 'danger model' is an alternative concept for immune response postulating that the immune system reacts to entities that do damage (danger associated molecular patterns, DAMP and not only to entities that are foreign (pathogen-associated molecular patterns, PAMP as proposed by classical immunology concepts. In this study we used Galleria mellonella to validate the danger model in insects. Hemolymph of G. mellonella was digested with thermolysin (as a representative for virulence-associated metalloproteinases produced by humanpathogens followed by chromatographic fractionation. Immune-stimulatory activity was tested by measuring lysozyme activity with the lytic zone assays against Micrococcus luteus cell wall components. Peptides were analyzed by nano-scale liquid chromatography coupled to high-resolution Fourier transform mass spectrometers. Addressing the lack of a genome sequence we complemented the rudimentary NCBI protein database with a recently established transcriptome and de novo sequencing methods for peptide identification. This approach led to identification of 127 peptides, 9 of which were identified in bioactive fractions. Detailed MS/MS experiments in comparison with synthetic analogues confirmed the amino acid sequence of all 9 peptides. To test the potential of these putative danger signals to induce immune responses we injected the synthetic analogues into G. mellonella and monitored the anti-bacterial activity against living Micrococcus luteus. Six out of 9 peptides identified in the bioactive fractions exhibited immune-stimulatory activity when injected. Hence, we provide evidence that small peptides resulting from thermolysin-mediated digestion of hemolymph proteins function as endogenous danger signals which can set the immune system into alarm. Consequently, our study indicates that the danger model also plays a role in insect immunity.

  14. Long-term predictions using natural analogues

    International Nuclear Information System (INIS)

    Ewing, R.C.

    1995-01-01

    One of the unique and scientifically most challenging aspects of nuclear waste isolation is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10 3 -10 5 years) required by regulatory agencies for performance assessment. The direct validation of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural systems (e.g., open-quotes natural analoguesclose quotes) provide perhaps the only means of partial open-quotes validation,close quotes as well as data that may be used directly in the models that are used in the extrapolation. Natural systems provide data on very large spatial (nm to km) and temporal (10 3 -10 8 years) scales and in highly complex terranes in which unknown synergisms may affect radionuclide migration. This paper reviews the application (and most importantly, the limitations) of data from natural analogue systems to the open-quotes validationclose quotes of performance assessments

  15. Can stroke patients use visual analogue scales?

    Science.gov (United States)

    Price, C I; Curless, R H; Rodgers, H

    1999-07-01

    Visual analogue scales (VAS) have been used for the subjective measurement of mood, pain, and health status after stroke. In this study we investigated how stroke-related impairments could alter the ability of subjects to answer accurately. Consent was obtained from 96 subjects with a clinical stroke (mean age, 72.5 years; 50 men) and 48 control subjects without cerebrovascular disease (mean age, 71.5 years; 29 men). Patients with reduced conscious level or severe dysphasia were excluded. Subjects were asked to rate the tightness that they could feel on the (unaffected) upper arm after 3 low-pressure inflations with a standard sphygmomanometer cuff, which followed a predetermined sequence (20 mm Hg, 40 mm Hg, 0 mm Hg). Immediately after each change, they rated the perceived tightness on 5 scales presented in a random order: 4-point rating scale (none, mild, moderate, severe), 0 to 10 numerical rating scale, mechanical VAS, horizontal VAS, and vertical VAS. Standard tests recorded deficits in language, cognition, and visuospatial awareness. Inability to complete scales with the correct pattern was associated with any stroke (P<0.001). There was a significant association between success using scales and milder clinical stroke subtype (P<0.01). Within the stroke group, logistic regression analysis identified significant associations (P<0.05) between impairments (cognitive and visuospatial) and inability to complete individual scales correctly. Many patients after a stroke are unable to successfully complete self-report measurement scales, including VAS.

  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. 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.

  18. Transferred nuclear Overhauser effect analyses of membrane-bound enkephalin analogues by sup 1 H nuclear magnetic resonance: Correlation between activities and membrane-bound conformations

    Energy Technology Data Exchange (ETDEWEB)

    Milon, Alain; Miyazawa, Tatsuo; Higashijima, Tsutomu (Univ. of Tokyo (Japan))

    1990-01-09

    Leu-enkephalin, (D-Ala{sup 2})Leu-enkephalin, and (D-Ala{sup 2})Leu-enkephalinamide (agonists) and (L-Ala{sup 2})Leu-enkephalin (inactive analogue) bind to lipid bilayer consisting of phosphatidylcholine and phosphatidylserine. The conformations that these compounds assume, once bound to perdeuterated phospholipid bilayer, have been shown to be unique, as shown by the transferred nuclear Overhauser effect (TRNOE) of {sup 1}H NMR spectroscopy. In addition, their location in the bilayer was analyzed by TRNOE in the presence of spin-labeled phospholipids. These analyses showed a clear relationship between the activity and the peptide-membrane interaction. The three active peptides, when bound to membranes, adopt the same conformation, characterized by a type II{prime} {beta}-turn around Gly{sup 3}-Phe and a {gamma}-turn around Gly{sup 2} (or D-Ala{sup 2}). The inactive analogue, (L-Ala{sup 2})Leu-enkephalin, displayed a completely different TRNOE pattern corresponding to a different conformation in the membrane-bound state. The tyrosine residue of the active compounds is not inserted into the interior of membrane, but it is inserted into the bilayer for the L-Ala{sup 2} analogue. According to these results, (L-Ala{sup 2})Leu-enkephalin may be explained to be inactive because the mode of binding to the membranes is different from that of active compounds.

  19. 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.

  20. d-Amino acid mutation of PMI as potent dual peptide inhibitors of p53-MDM2/MDMX interactions.

    Science.gov (United States)

    Li, Xiang; Liu, Chao; Chen, Si; Hu, Honggang; Su, Jiacan; Zou, Yan

    2017-10-15

    According to the previously reported potent dual l-peptide PMI of p53-MDM2/MDMX interactions, a series of d-amino acid mutational PMI analogues, PMI-1-4, with enhanced proteolytic resistence and in vitro tumor cell inhibitory activities were reported, of which Liposome-PMI-1 showed a stronger inhibitory activity against the U87 cell lines than Nutlin-3. This d-amino acid mutation strategy may give a hand for enhancing the potential of peptide drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. an assessment of billing electricity consumers via analogue meters

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. This paper assesses the perception of billing consumers via analogue meter in Kano Electricity ... the successor companies of Power Holding Company ... Nassarawa computer center was established in 1991. .... The value 7.2 is.

  2. Solistatinol, a novel phenolic compactin analogue from Penicillium solitum

    DEFF Research Database (Denmark)

    Larsen, Thomas Ostenfeld; Lange, Lene; Schnorr, Kirk

    2007-01-01

    Solistatinol, a novel phenolic compactin analogue, has been isolated from Penicillium solitum using a UV-guided strategy. The structure and relative stereochemistry were determined by NMR spectroscopy and mass spectrometry. The absolute stereochemistry was determined by chemical degradation...

  3. From BPA to its analogues: Is it a safe journey?

    Science.gov (United States)

    Usman, Afia; Ahmad, Masood

    2016-09-01

    Bisphenol-A (BPA) is one of the most abundant synthetic chemicals in the world due to its uses in plastics. Its widespread exposure vis-a-vis low dose effects led to a reduction in its safety dose and imposition of ban on its use in infant feeding bottles. This restriction paved the way for the gradual market entry of its analogues. However, their structural similarity to BPA has put them under surveillance for endocrine disrupting potential. The application of these analogues is increasing and so are the studies reporting their toxicity. This review highlights the reasons which led to the ban of BPA and also reports the exposure and toxicological data available on its analogues. Hence, this compilation is expected to answer in a better way whether the replacement of BPA by these analogues is safer or more harmful? Copyright © 2016. Published by Elsevier Ltd.

  4. Synthesis and antiplatelet activity of thioaryloxyacids analogues of clofibric acid.

    Science.gov (United States)

    Ammazzalorso, Alessandra; Amoroso, Rosa; Baraldi, Mario; Bettoni, Giancarlo; Braghiroli, Daniela; De Filippis, Barbara; Giampietro, Letizia; Tricca, Maria L; Vezzalini, Francesca

    2005-09-01

    The thiophene-, benzothiazole- and pyridine-thioaryloxyacids analogues of clofibric acid were synthesized and their antiplatelet activity was screened. Some compounds exhibited antiaggregating properties. The platelet-related haemostasis was measured on a PFA-100 analyzer using bull blood.

  5. Modeling of NAD+ analogues in horse liver alcohol dehydrogenase

    NARCIS (Netherlands)

    Beijer, N.A.; Buck, H.M.; Sluyterman, L.A.A.E.; Meijer, E.M.

    1990-01-01

    So far, the interactions of nicotinamide adenine dinucleotide (NAD+) derivatives with dehydrogenases are not very well understood. This hampers the introduction of NAD+ analogues with improved characteristics concerning industrial application. We have developed an AMBER molecular mechanics model in

  6. Algorithmic fundamentals of computerized tomography and of transverse analogue tomography

    International Nuclear Information System (INIS)

    Heckmann, K.

    1981-01-01

    Computerized tomography and transverse analogue tomography are two different approaches to the same goal, namely, transverse tomography. The algorithm is discussed and compared. Transverse tomography appears capable of further development, judging by this comparison. (orig.) [de

  7. Analogue and Mixed-Signal Integrated Circuits for Space Applications

    CERN Document Server

    2014-01-01

    The purpose of AMICSA 2014 (organised in collaboration of ESA and CERN) is to provide an international forum for the presentation and discussion of recent advances in analogue and mixed-signal VLSI design techniques and technologies for space applications.

  8. an assessment of billing electricity consumers via analogue meters

    African Journals Online (AJOL)

    DR. AMINU

    Keywords: Electricity Distribution, Consumers, Analogue Meter, Billing, Nigeria. INTRODUCTION. Electricity ... the energy usage of a typical electricity consumer in one month is several ..... improve on distribution network. In addition it should.

  9. Insulin analogues in pregnancy and specific congenital anomalies

    DEFF Research Database (Denmark)

    de Jong, Josta; Garne, Ester; Wender-Ozegowska, Ewa

    2016-01-01

    Insulin analogues are commonly used in pregnant women with diabetes. It is not known if the use of insulin analogues in pregnancy is associated with any higher risk of congenital anomalies in the offspring compared with use of human insulin. We performed a literature search for studies of pregnant...... women with pregestational diabetes using insulin analogues in the first trimester and information on congenital anomalies. The studies were analysed to compare the congenital anomaly rate among foetuses of mothers using insulin analogues with foetuses of mothers using human insulin. Of 29 studies, we...... samples in the included studies provided insufficient statistical power to identify a moderate increased risk of specific congenital anomalies. Copyright © 2015 John Wiley & Sons, Ltd....

  10. Enhancement of endotoxin neutralization by coupling of a C12-alkyl chain to a lactoferricin-derived peptide

    Science.gov (United States)

    2004-01-01

    Antibacterial peptide acylation, which mimics the structure of the natural lipopeptide polymyxin B, increases antimicrobial and endotoxin-neutralizing activities. The interaction of the lactoferricin-derived peptide LF11 and its N-terminally acylated analogue, lauryl-LF11, with different chemotypes of bacterial lipopolysaccharide (LPS Re, Ra and smooth S form) was investigated by biophysical means and was related to the peptides' biological activities. Both peptides exhibit high antibacterial activity against the three strains of Salmonella enterica differing in the LPS chemotype. Lauryl-LF11 has one order of magnitude higher activity against Re-type, but activity against Ra- and S-type bacteria is comparable with that of LF11. The alkyl derivative peptide lauryl-LF11 shows a much stronger inhibition of the LPS-induced cytokine induction in human mononuclear cells than LF11. Although peptide–LPS interaction is essentially of electrostatic nature, the lauryl-modified peptide displays a strong hydrophobic component. Such a feature might then explain the fact that saturation of the peptide binding takes place at a much lower peptide/LPS ratio for LF11 than for lauryl-LF11, and that an overcompensation of the negative LPS backbone charges is observed for lauryl-LF11. The influence of LF11 on the gel-to-liquid-crystalline phase-transition of LPS is negligible for LPS Re, but clearly fluidizing for LPS Ra. In contrast, lauryl-LF11 causes a cholesterol-like effect in the two chemotypes, fluidizing in the gel and rigidifying of the hydrocarbon chains in the liquid-crystalline phase. Both peptides convert the mixed unilamellar/non-lamellar aggregate structure of lipid A, the ‘endotoxic principle’ of LPS, into a multilamellar one. These data contribute to the understanding of the mechanisms of the peptide-mediated neutralization of endotoxin and effect of lipid modification of peptides. PMID:15344905

  11. Protective effects of TRH and its analogues against various cytotoxic agents in retinoic acid (RA)-differentiated human neuroblastoma SH-SY5Y cells.

    Science.gov (United States)

    Jaworska-Feil, L; Jantas, D; Leskiewicz, M; Budziszewska, B; Kubera, M; Basta-Kaim, A; Lipkowski, A W; Lason, W

    2010-12-01

    TRH (thyroliberin) and its analogues were reported to possess neuroprotective effects in cellular and animal experimental models of acute and chronic neurodegenerative diseases. In the present study we evaluated effects of TRH and its three stable analogues, montirelin (CG-3703), RGH-2202 and Z-TRH (N-(carbobenzyloxy)-pGlutamyl-Histydyl-Proline) on the neuronally differentiated human neuroblastoma SH-SY5Y cell line, which is widely accepted for studying potential neuroprotectants. We found that TRH and all the tested analogues at concentrations 0.1-50 μM attenuated cell damage induced by MPP(+) (2 mM), 3-nitropropionate (10 mM), hydrogen peroxide (0.5 mM), homocysteine (250 μM) and beta-amyloid (20μM) in retinoic acid differentiated SH-SY5Y cells. Furthermore, we demonstrated that TRH and its analogues decreased the staurosporine (0.5 μM)-induced LDH release, caspase-3 activity and DNA fragmentation, which indicate the anti-apoptotic proprieties of these peptides. The neuroprotective effects of TRH (10 μM) and RGH-2202 (10 μM) on St-induced cell death was attenuated by inhibitors of PI3-K pathway (wortmannin and LY294002), but not MAPK/ERK1/2 (PD98059 and U0126). Moreover, TRH and its analogues at neuroprotective concentrations (1 and 10 μM) increased expression of Bcl-2 protein, as confirmed by Western blot analysis. All in all, these results extend data on neuroprotective properties of TRH and its analogues and provide evidence that mechanism of anti-apoptotic effects of these peptides in SH-SY5Y cell line involves induction of PI3K/Akt pathway and Bcl-2. Furthermore, the data obtained on human cell line with a dopaminergic phenotype suggest potential utility of TRH and its analogues in the treatment of some neurodegenerative diseases including Parkinson's disease. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Mathematics revealed

    CERN Document Server

    Berman, Elizabeth

    1979-01-01

    Mathematics Revealed focuses on the principles, processes, operations, and exercises in mathematics.The book first offers information on whole numbers, fractions, and decimals and percents. Discussions focus on measuring length, percent, decimals, numbers as products, addition and subtraction of fractions, mixed numbers and ratios, division of fractions, addition, subtraction, multiplication, and division. The text then examines positive and negative numbers and powers and computation. Topics include division and averages, multiplication, ratios, and measurements, scientific notation and estim

  13. 3-alkyl fentanyl analogues: Structure-activity-relationship study

    OpenAIRE

    Vučković, Sonja; Savić-Vujović, Katarina; Srebro, Dragana; Ivanović, Milovan; Došen-Mićović, Ljiljana; Stojanović, Radan; Prostran, Milica

    2012-01-01

    Introduction. Fentanyl belongs to 4-anilidopiperidine class of synthetic opioid analgesics. It is characterized by high potency, rapid onset and short duration of action. A large number of fentanyl analogues have been synthesized so far, both to establish the structure-activity-relationship (SAR) and to find novel, clinically useful analgesic drugs. Objective. In this study, newly synthesized 3-alkyl fentanyl analogues were examined for analgesic activity and compared with fentanyl. Methods. ...

  14. Analogue Signal Processing: Collected Papers 1994-95

    DEFF Research Database (Denmark)

    1996-01-01

    This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of Electronics Institute, Technical University of Denmark, in 1994 and 1995.......This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of Electronics Institute, Technical University of Denmark, in 1994 and 1995....

  15. Analogue Signal Processing: Collected Papers 1996-97

    DEFF Research Database (Denmark)

    1997-01-01

    This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of the Department of Information Technology, Technical University of Denmark, in 1996 and 1997.......This document is a collection of the papers presented at international conferences and in international journals by the analogue signal processing group of the Department of Information Technology, Technical University of Denmark, in 1996 and 1997....

  16. Synthesis of tritium labelled phosphonate analogues of sphinganine-1-phosphate

    International Nuclear Information System (INIS)

    Schick, Andreas; Schwarzmann, Guenter; Kolter, Thomas; Sandhoff, Konrad

    1997-01-01

    Tritiated phosphonate analogues 9 and 10 are prepared as analogues of sphinganine-1-phosphate 4. The key step in this synthesis is the catalytic tritiation of the triple bond in reduction of the protected diethyl-3-(S)-tert.-butoxycarbonylamino -4-hydroxy-5-tridecinyl-1-phosphonate by means of sodium boro[ 3 H]hydride as tritium source. These compounds are synthesized to study their metabolic stability and to evaluate their biological properties. (author)

  17. The Greenland Analogue Project, Yearly Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-08-15

    To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a realistic understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. The project includes three sub-projects (A-C) with specific individual objectives, which collectively aim at contributing knowledge and input to the overall project aim. Three field campaigns were carried out in SPA during 2009. These campaigns focused on: (1) deployment and maintenance of AWS and GPS stations and to test the deep-look radar equipment; (2) investigating the hydrological processes and feedbacks and testing of passive seismic equipment; (3) downloading of weather station data and GPS data and winterizing the equipment. An extensive archive of real-time satellite remote sensing datasets has been obtained to be able to better constraint the surface elevation and dynamics of basal hydrological mechanisms. From this archive it has been possible to obtain Russell Glacier Cachment (RGC)-wide constraints on annual, seasonal and specific temporal snapshots of surface speed, initial lake and moulin distribution, drainage and network connections along with the temporal

  18. The Greenland Analogue Project, Yearly Report 2009

    International Nuclear Information System (INIS)

    2011-08-01

    To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a realistic understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. The project includes three sub-projects (A-C) with specific individual objectives, which collectively aim at contributing knowledge and input to the overall project aim. Three field campaigns were carried out in SPA during 2009. These campaigns focused on: (1) deployment and maintenance of AWS and GPS stations and to test the deep-look radar equipment; (2) investigating the hydrological processes and feedbacks and testing of passive seismic equipment; (3) downloading of weather station data and GPS data and winterizing the equipment. An extensive archive of real-time satellite remote sensing datasets has been obtained to be able to better constraint the surface elevation and dynamics of basal hydrological mechanisms. From this archive it has been possible to obtain Russell Glacier Cachment (RGC)-wide constraints on annual, seasonal and specific temporal snapshots of surface speed, initial lake and moulin distribution, drainage and network connections along with the temporal

  19. Sialic acid (SA)-modified selenium nanoparticles coated with a high blood-brain barrier permeability peptide-B6 peptide for potential use in Alzheimer's disease.

    Science.gov (United States)

    Yin, Tiantian; Yang, Licong; Liu, Yanan; Zhou, Xianbo; Sun, Jing; Liu, Jie

    2015-10-01

    The blood-brain barrier (BBB) is a formidable gatekeeper toward exogenous substances, playing an important role in brain homeostasis and maintaining a healthy microenvironment for complex neuronal activities. However, it also greatly hinders drug permeability into the brain and limits the management of brain diseases. The development of new drugs that show improved transport across the BBB represents a promising strategy for Alzheimer's disease (AD) intervention. Whereas, previous study of receptor-mediated endogenous BBB transport systems has focused on a strategy of using transferrin to facilitate brain drug delivery system, a system that still suffers from limitations including synthesis procedure, stability and immunological response. In the present study, we synthetised sialic acid (SA)-modified selenium (Se) nanoparticles conjugated with an alternative peptide-B6 peptide (B6-SA-SeNPs, a synthetic selenoprotein analogue), which shows high permeability across the BBB and has the potential to serve as a novel nanomedicine for disease modification in AD. Laser-scanning confocal microscopy, flow cytometry analysis and inductively coupled plasma-atomic emission spectroscopy ICP-AES revealed high cellular uptake of B6-SA-SeNPs by cerebral endothelial cells (bEnd.3). The transport efficiency of B6-SA-SeNPs was evaluated in a Transwell experiment based on in vitro BBB model. It provided direct evidence for B6-SA-SeNPs crossing the BBB and being absorbed by PC12 cells. Moreover, inhibitory effects of B6-SA-SeNPs on amyloid-β peptide (Aβ) fibrillation could be demonstrated in PC12 cells and bEnd3 cells. B6-SA-SeNPs could not only effectively inhibit Aβ aggregation but could disaggregate preformed Aβ fibrils into non-toxic amorphous oligomers. These results suggested that B6-SA-SeNPs may provide a promising platform, particularly for the application of nanoparticles in the treatment of brain diseases. Alzheimer's disease (AD) is the world's most common form of

  20. Optimization and in Vivo Validation of Peptide Vectors Targeting the LDL Receptor.

    Science.gov (United States)

    Jacquot, Guillaume; Lécorché, Pascaline; Malcor, Jean-Daniel; Laurencin, Mathieu; Smirnova, Maria; Varini, Karine; Malicet, Cédric; Gassiot, Fanny; Abouzid, Karima; Faucon, Aude; David, Marion; Gaudin, Nicolas; Masse, Maxime; Ferracci, Géraldine; Dive, Vincent; Cisternino, Salvatore; Khrestchatisky, Michel

    2016-12-05

    Active targeting and delivery to pathophysiological organs of interest is of paramount importance to increase specific accumulation of therapeutic drugs or imaging agents while avoiding systemic side effects. We recently developed a family of new peptide ligands of the human and rodent LDL receptor (LDLR), an attractive cell-surface receptor with high uptake activity and local enrichment in several normal or pathological tissues (Malcor et al., J. Med. Chem. 2012, 55 (5), 2227). Initial chemical optimization of the 15-mer, all natural amino acid compound 1/VH411 (DSGL[CMPRLRGC] c DPR) and structure-activity relationship (SAR) investigation led to the cyclic 8 amino acid analogue compound 22/VH445 ([cMPRLRGC] c ) which specifically binds hLDLR with a K D of 76 nM and has an in vitro blood half-life of ∼3 h. Further introduction of non-natural amino acids led to the identification of compound 60/VH4106 ([(d)-"Pen"M"Thz"RLRGC] c ), which showed the highest K D value of 9 nM. However, this latter analogue displayed the lowest in vitro blood half-life (∼1.9 h). In the present study, we designed a new set of peptide analogues, namely, VH4127 to VH4131, with further improved biological properties. Detailed analysis of the hLDLR-binding kinetics of previous and new analogues showed that the latter all displayed very high on-rates, in the 10 6 s -1. M -1 range, and off-rates varying from the low 10 -2 s -1 to the 10 -1 s -1 range. Furthermore, all these new analogues showed increased blood half-lives in vitro, reaching ∼7 and 10 h for VH4129 and VH4131, respectively. Interestingly, we demonstrate in cell-based assays using both VH445 and the most balanced optimized analogue VH4127 ([cM"Thz"RLRG"Pen"] c ), showing a K D of 18 nM and a blood half-life of ∼4.3 h, that its higher on-rate correlated with a significant increase in both the extent of cell-surface binding to hLDLR and the endocytosis potential. Finally, intravenous injection of tritium-radiolabeled 3 H

  1. Characterisation of insulin analogues therapeutically available to patients

    KAUST Repository

    Adams, Gary G.

    2018-03-29

    The structure and function of clinical dosage insulin and its analogues were assessed. This included \\'native insulins\\' (human recombinant, bovine, porcine), \\'fast-acting analogues\\' (aspart, glulisine, lispro) and \\'slow-acting analogues\\' (glargine, detemir, degludec). Analytical ultracentrifugation, both sedimentation velocity and equilibrium experiments, were employed to yield distributions of both molar mass and sedimentation coefficient of all nine insulins. Size exclusion chromatography, coupled to multi-angle light scattering, was also used to explore the function of these analogues. On ultracentrifugation analysis, the insulins under investigation were found to be in numerous conformational states, however the majority of insulins were present in a primarily hexameric conformation. This was true for all native insulins and two fast-acting analogues. However, glargine was present as a dimer, detemir was a multi-hexameric system, degludec was a dodecamer (di-hexamer) and glulisine was present as a dimer-hexamer-dihexamer system. However, size-exclusion chromatography showed that the two hexameric fast-acting analogues (aspart and lispro) dissociated into monomers and dimers due to the lack of zinc in the mobile phase. This comprehensive study is the first time all nine insulins have been characterised in this way, the first time that insulin detemir have been studied using analytical ultracentrifugation and the first time that insulins aspart and glulisine have been studied using sedimentation equilibrium. The structure and function of these clinically administered insulins is of critical importance and this research adds novel data to an otherwise complex functional physiological protein.

  2. Application of natural analogues in the Yucca Mountain project - overview

    International Nuclear Information System (INIS)

    Simmons, Ardyth M.

    2003-01-01

    The Natural Analogue Synthesis Report (NASR) [1] provides a compilation of information from analogues that test, corroborate, and add confidence to process models and model predictions pertinent to total system performance assessment (TSPA). The report updated previous work [2] with new literature examples and results of quantitative studies conducted by the Yucca Mountain Project (YMP). The intent of the natural analogue studies was to collect corroborative evidence from analogues to demonstrate greater understanding of processes expected to occur during postclosure of a proposed Yucca Mountain repository. Natural analogues, as used here, refer to either natural or anthropogenic systems in which processes similar to those expected to occur in a nuclear waste repository are thought to have occurred over long time periods (decades to millenia) and large spatial scales (up to tens of kilometers). In the past, the YMP has used analogues for testing and building confidence in conceptual and numerical process models in a number of ways. Yucca Mountain mineral alteration phases provided a self-analogue for postclosure alteration [3]. Thermodynamic parameters for silica minerals of the Wairakai, New Zealand geothermal field were added to databases used in geochemical modeling [4]. Scoping calculations of radionuclide transport using the Yucca Mountain TSPA numerical model were conducted for the Peqa Blanca site [5]. Eruption parameters from the Cerro Negro volcano, Nicaragua, were used to verify codes that model ash plume dispersion [6]. Analogues have also been used in supplemental science and performance analyses to provide multiple lines of evidence in support of both analyses and model reports (AMRs) [7]; in screening arguments for inclusion or exclusion of features, events, and processes (FEP)s in TSPAs; in the quantification of uncertainties [7]; in expert elicitations of volcanic and seismic hazards [8, 9] and in peer reviews [10]. Natural analogues may be applied

  3. Habitability & Astrobiology Research in Mars Terrestrial Analogues

    Science.gov (United States)

    Foing, Bernard

    2014-05-01

    We performed a series of field research campaigns (ILEWG EuroMoonMars) in the extreme Utah desert relevant to Mars environments, and in order to help in the interpretation of Mars missions measurements from orbit (MEX, MRO) or from the surface (MER, MSL), or Moon geochemistry (SMART-1, LRO). We shall give an update on the sample analysis in the context of habitability and astrobiology. Methods & Results: In the frame of ILEWG EuroMoonMars campaigns (2009 to 2013) we deployed at Mars Desert Research station, near Hanksville Utah, a suite of instruments and techniques [A, 1, 2, 9-11] including sample collection, context imaging from remote to local and microscale, drilling, spectrometers and life sensors. We analyzed how geological and geochemical evolution affected local parameters (mineralogy, organics content, environment variations) and the habitability and signature of organics and biota. Among the important findings are the diversity in the composition of soil samples even when collected in close proximity, the low abundances of detectable PAHs and amino acids and the presence of biota of all three domains of life with significant heterogeneity. An extraordinary variety of putative extremophiles was observed [3,4,9]. A dominant factor seems to be soil porosity and lower clay-sized particle content [6-8]. A protocol was developed for sterile sampling, contamination issues, and the diagnostics of biodiversity via PCR and DGGE analysis in soils and rocks samples [10, 11]. We compare the 2009 campaign results [1-9] to new measurements from 2010-2013 campaigns [10-12] relevant to: comparison between remote sensing and in-situ measurements; the study of minerals; the detection of organics and signs of life. Keywords: field analogue research, astrobiology, habitability, life detection, Earth-Moon-Mars, organics References [A] Foing, Stoker & Ehrenfreund (Editors, 2011) "Astrobiology field Research in Moon/Mars Analogue Environments", Special Issue of International

  4. Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

    Science.gov (United States)

    Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

    2015-01-01

    Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

  5. Hierarchical assembly of branched supramolecular polymers from (cyclic Peptide)-polymer conjugates.

    Science.gov (United States)

    Koh, Ming Liang; Jolliffe, Katrina A; Perrier, Sébastien

    2014-11-10

    We report the synthesis and assembly of (N-methylated cyclic peptide)-polymer conjugates for which the cyclic peptide is attached to either the α- or both α- and ω- end groups of a polymer. A combination of chromatographic, spectroscopic, and scattering techniques reveals that the assembly of the conjugates follows a two-level hierarchy, initially driven by H-bond formation between two N-methylated cyclic peptides, followed by unspecific, noncovalent aggregation of this peptide into small domains that behave as branching points and lead to the formation of branched supramolecular polymers.

  6. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

  7. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    N.D. Zegers (Netty)

    1995-01-01

    textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

  8. Peptide radiopharmaceuticals in nuclear medicine

    International Nuclear Information System (INIS)

    Blok, D.; Vermeij, P.; Feitsma, R.I.J.; Pauwels, E.J.K.

    1999-01-01

    This article reviews the labelling of peptides that are recognised to be of interest for nuclear medicine or are the subject of ongoing nuclear medicine research. Applications and approaches to the labelling of peptide radiopharmaceuticals are discussed, and drawbacks in their development considered. (orig.)

  9. Fingerprinting Desmosine-Containing Elastin Peptides

    Science.gov (United States)

    Schräder, Christoph U.; Heinz, Andrea; Majovsky, Petra; Schmelzer, Christian E. H.

    2015-05-01

    Elastin is a vital protein of the extracellular matrix of jawed vertebrates and provides elasticity to numerous tissues. It is secreted in the form of its soluble precursor tropoelastin, which is subsequently cross-linked in the course of the elastic fiber assembly. The process involves the formation of the two tetrafunctional amino acids desmosine (DES) and isodesmosine (IDES), which are unique to elastin. The resulting high degree of cross-linking confers remarkable properties, including mechanical integrity, insolubility, and long-term stability to the protein. These characteristics hinder the structural elucidation of mature elastin. However, MS2 data of linear and cross-linked peptides released by proteolysis can provide indirect insights into the structure of elastin. In this study, we performed energy-resolved collision-induced dissociation experiments of DES, IDES, their derivatives, and DES-/IDES-containing peptides to determine characteristic product ions. It was found that all investigated compounds yielded the same product ion clusters at elevated collision energies. Elemental composition determination using the exact masses of these ions revealed molecular formulas of the type CxHyN, suggesting that the pyridinium core of DES/IDES remains intact even at relatively high collision energies. The finding of these specific product ions enabled the development of a similarity-based scoring algorithm that was successfully applied on LC-MS/MS data of bovine elastin digests for the identification of DES-/IDES-cross-linked peptides. This approach facilitates the straightforward investigation of native cross-links in elastin.

  10. N-acylated peptides derived from human lactoferricin perturb organization of cardiolipin and phosphatidylethanolamine in cell membranes and induce defects in Escherichia coli cell division.

    Directory of Open Access Journals (Sweden)

    Dagmar Zweytick

    Full Text Available Two types of recently described antibacterial peptides derived from human lactoferricin, either nonacylated or N-acylated, were studied for their different interaction with membranes of Escherichia coli in vivo and in model systems. Electron microscopy revealed striking effects on the bacterial membrane as both peptide types induced formation of large membrane blebs. Electron and fluorescence microscopy, however demonstrated that only the N-acylated peptides partially induced the generation of oversized cells, which might reflect defects in cell-division. Further a different distribution of cardiolipin domains on the E. coli membrane was shown only in the presence of the N-acylated peptides. The lipid was distributed over the whole bacterial cell surface, whereas cardiolipin in untreated and nonacylated peptide-treated cells was mainly located at the septum and poles. Studies with bacterial membrane mimics, such as cardiolipin or phosphatidylethanolamine revealed that both types of peptides interacted with the negatively charged lipid cardiolipin. The nonacylated peptides however induced segregation of cardiolipin into peptide-enriched and peptide-poor lipid domains, while the N-acylated peptides promoted formation of many small heterogeneous domains. Only N-acylated peptides caused additional severe effects on the main phase transition of liposomes composed of pure phosphatidylethanolamine, while both peptide types inhibited the lamellar to hexagonal phase transition. Lipid mixtures of phosphatidylethanolamine and cardiolipin revealed anionic clustering by all peptide types. However additional strong perturbation of the neutral lipids was only seen with the N-acylated peptides. Nuclear magnetic resonance demonstrated different conformational arrangement of the N-acylated peptide in anionic and zwitterionic micelles revealing possible mechanistic differences in their action on different membrane lipids. We hypothesized that both peptides kill

  11. Significance of production of peptide leukotrienes in murine traumatic shock

    International Nuclear Information System (INIS)

    Craft, D.V.; Lefer, D.J.; Hock, C.E.; Lefer, A.M.

    1986-01-01

    The authors studied the formation of a leukotriene metabolite in plasma and bile during traumatic shock. Anesthetized rats subjected to Noble-Collip drum trauma developed a lethal shock state characterized by a survival time of 1.9 +/- 0.3h, a 4.5-fold increase in plasma cathepsin D activity, and a reduction in mean arterial blood pressure to 45 +/- 2 mmHg compared with 108 +/- 5 mmHg in sham-shock controls. Plasma and bile s