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Sample records for thyrotropin structural elucidation

  1. Asparagine-linked oligosaccharides on lutropin, follitropin, and thyrotropin: structural elucidation of the sulfated and sialylated oligosaccharides on bovine, ovine, and human pituitary glycoprotein hormones

    International Nuclear Information System (INIS)

    Green, E.D.; Baenziger, J.U.

    1988-01-01

    The authors have elucidated the structures of the anionic asparagine-linked oligosaccharides present on the glycoprotein hormones lutropin (luteinizing hormone), follitropin (follicle-stimulating hormone), and thyrotropin (thyroid-stimulating hormone). Purified hormones, isolated from bovine, ovine, and human pituitaries, were digested with N-glycanase, and the released oligosaccharides were reduced with NaB[ 3 H] 4 . The 3 H-labeled oligosaccharides from each hormone were then fractionated by anion-exchange high performance liquid chromatography (HPLC) into populations differing in the number of sulfate and/or sialic acid moieties. The sulfated, sialylated, and sulfated/sialylated structures, which together comprised 67-90% of the asparagine-linked oligosaccharides on the pituitary glycoprotein hormones, were highly heterogeneous and displayed hormone- as well as animal species-specific features. A previously uncharacterized dibranched oligosaccharide, bearing one residue each of sulfate and sialic acid, was found on all of the hormones except bovine lutropin. In this study, they describe the purification and detailed structural characterizations of the sulfated, sialylated, and sulfated/sialylated oligosaccharides found on lutropin, follitropin, and thyrotropin from several animal species

  2. Defining structural and functional dimensions of the extracellular thyrotropin receptor region.

    Science.gov (United States)

    Kleinau, Gunnar; Mueller, Sandra; Jaeschke, Holger; Grzesik, Paul; Neumann, Susanne; Diehl, Anne; Paschke, Ralf; Krause, Gerd

    2011-06-24

    The extracellular region of the thyrotropin receptor (TSHR) can be subdivided into the leucine-rich repeat domain (LRRD) and the hinge region. Both the LRRD and the hinge region interact with thyrotropin (TSH) or autoantibodies. Structural data for the TSHR LRRD were previously determined by crystallization (amino acids Glu(30)-Thr(257), 10 repeats), but the structure of the hinge region is still undefined. Of note, the amino acid sequence (Trp(258)-Tyr(279)) following the crystallized LRRD comprises a pattern typical for leucine-rich repeats with conserved hydrophobic side chains stabilizing the repeat fold. Moreover, functional data for amino acids between the LRRD and the transmembrane domain were fragmentary. We therefore investigated systematically these TSHR regions by mutagenesis to reveal insights into their functional contribution and potential structural features. We found that mutations of conserved hydrophobic residues between Thr(257) and Tyr(279) cause TSHR misfold, which supports a structural fold of this peptide, probably as an additional leucine-rich repeat. Furthermore, we identified several new mutations of hydrophilic amino acids in the entire hinge region leading to partial TSHR inactivation, indicating that these positions are important for intramolecular signal transduction. In summary, we provide new information regarding the structural features and functionalities of extracellular TSHR regions. Based on these insights and in context with previous results, we suggest an extracellular activation mechanism that supports an intramolecular agonistic unit as a central switch for activating effects at the extracellular region toward the serpentine domain.

  3. Structural elucidation of nanocrystalline biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Maltsev, S.

    2008-10-23

    Bone diseases, such as osteoporosis and osteoarthritis, are the second most prevalent health problem worldwide. In Germany approximately 5 millions people are affected by arthritis. Investigating biomineralization processes and bone molecular structure is of key importance for developing new drugs for preventing and healing bone diseases. Nuclear magnetic resonance (NMR) was the primary technique used due to its advantages in characterising poorly ordered and disordered materials. Compared to all the diffraction techniques that widely applied in structural investigations, the usefulness of NMR is independent of long range molecular order. This makes NMR an outstanding technique for studies of complex/amorphous materials. Conventional NMR experiments (single pulse, spin-echo, cross polarization (CP), etc.) as well as their modifications and high-end techniques (2D HETCOR, REDOR, etc.) were used in this work. Combining the contributions from different techniques enhances the information content of the investigations and can increase the precision of the overall conclusions. Also XRD, TEM and FTIR were applied to different extent in order to get a general idea of nanocrystalline hydroxyapatite crystallite structure. Results: - A new approach named 'Solid-state NMR spectroscopy using the lost I spin magnetization in polarization transfer experiments' has been developed for measuring the transferred I spin magnetization from abundant nuclei, which is normally lost when detecting the S spin magnetization. - A detailed investigation of nanocrystalline hydroxyapatite core was made to prove that proton environment of the phosphates units and phosphorus environment of hydroxyl units are the same as in highly crystalline hydroxyapatite sample. - Using XRD it was found that the surface of the hydroxyapatite nanocrystals is not completely disordered, as it was suggested before, but resembles the hydroxyapatite structure with HPO{sub 4}{sup 2-} (and some CO{sub 3}{sup

  4. Structural-Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work.

    Science.gov (United States)

    Kleinau, Gunnar; Worth, Catherine L; Kreuchwig, Annika; Biebermann, Heike; Marcinkowski, Patrick; Scheerer, Patrick; Krause, Gerd

    2017-01-01

    The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to

  5. Using Genomics for Natural Product Structure Elucidation.

    Science.gov (United States)

    Tietz, Jonathan I; Mitchell, Douglas A

    2016-01-01

    Natural products (NPs) are the most historically bountiful source of chemical matter for drug development-especially for anti-infectives. With insights gleaned from genome mining, interest in natural product discovery has been reinvigorated. An essential stage in NP discovery is structural elucidation, which sheds light not only on the chemical composition of a molecule but also its novelty, properties, and derivatization potential. The history of structure elucidation is replete with techniquebased revolutions: combustion analysis, crystallography, UV, IR, MS, and NMR have each provided game-changing advances; the latest such advance is genomics. All natural products have a genetic basis, and the ability to obtain and interpret genomic information for structure elucidation is increasingly available at low cost to non-specialists. In this review, we describe the value of genomics as a structural elucidation technique, especially from the perspective of the natural product chemist approaching an unknown metabolite. Herein we first introduce the databases and programs of interest to the natural products chemist, with an emphasis on those currently most suited for general usability. We describe strategies for linking observed natural product-linked phenotypes to their corresponding gene clusters. We then discuss techniques for extracting structural information from genes, illustrated with numerous case examples. We also provide an analysis of the biases and limitations of the field with recommendations for future development. Our overview is not only aimed at biologically-oriented researchers already at ease with bioinformatic techniques, but also, in particular, at natural product, organic, and/or medicinal chemists not previously familiar with genomic techniques.

  6. Isolation and structural elucidation of compounds from the non ...

    African Journals Online (AJOL)

    CARTA

    Isolation and structural elucidation of compounds from the non-alkaloidal extract of Nicandra physaloides ... were fractionated using a glass column whose ... Structure elucidation. Using spectroscopic methods, three compounds were identified; two compounds (β-sitosterol and stigmasterol) were isolated from fraction F2.

  7. Structural elucidation of inhomogeneous lignins from bamboo.

    Science.gov (United States)

    Wen, Jia-Long; Sun, Shao-Long; Xue, Bai-Liang; Sun, Run-Cang

    2015-01-01

    A better understanding of the inhomogeneous molecular structure of lignin from bamboo is a prerequisite for promoting the "biorefinery" technologies of the bamboo feedstock. A mild and successive method for fractionating native lignin from bamboo species was proposed in the present study. The molecular structure and structural inhomogeneity of the isolated lignin polymers were comprehensively investigated by elemental analysis, carbohydrate analysis, state-of-the-art NMR and analytical pyrolysis techniques (quantitative (13)C NMR, (13)C-DEPT 135 NMR, 2D-HSQC NMR, (31)P NMR, and pyrolysis-GC-MS). The results showed that the proposed method is effective for extracting lignin from bamboo. NMR results showed that syringyl (S) was the predominant unit in bamboo lignin over guaiacyl (G) and p-hydroxyphenyl (H) units. In addition, the lignin was associated with p-coumarates and ferulates via ester and ether bonds, respectively. Moreover, various substructures, such as β-O-4, β-β, β-5, β-1, and α,β-diaryl ether linkages, were identified and quantified by NMR techniques. Based on the results obtained, a proposed schematic diagram of structural heterogeneity of the lignin polymers extracted from the bamboo is presented. In short, well-defined inhomogeneous structures of native lignin from bamboo will facilitate further applications of bamboo in current biorefineries. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Extended and structurally supported insights into extracellular hormone binding, signal transduction and organization of the thyrotropin receptor.

    Directory of Open Access Journals (Sweden)

    Gerd Krause

    Full Text Available The hormone thyrotropin (TSH and its receptor (TSHR are crucial for the growth and function of the thyroid gland. The TSHR is evolutionary linked with the receptors of follitropin (FSHR and lutropin/choriogonadotropin (LHR and their sequences and structures are similar. The extracellular region of TSHR contains more than 350 amino acids and binds hormone and antibodies. Several important questions related to functions and mechanisms of TSHR are still not comprehensively understood. One major reason for these open questions is the lack of any structural information about the extracellular segment of TSHR that connects the N-terminal leucine-rich repeat domain (LRRD with the transmembrane helix (TMH 1, the hinge region. It has been shown experimentally that this segment is important for fine tuning of signaling and ligand interactions. A new crystal structure containing most of the extracellular hFSHR region in complex with hFSH has recently been published. Now, we have applied these new structural insights to the homologous TSHR and have generated a structural model of the TSHR LRRD/hinge-region/TSH complex. This structural model is combined and evaluated with experimental data including hormone binding (bTSH, hTSH, thyrostimulin, super-agonistic effects, antibody interactions and signaling regulation. These studies and consideration of significant and non-significant amino acids have led to a new description of mechanisms at the TSHR, including ligand-induced displacements of specific hinge region fragments. This event triggers conformational changes at a convergent center of the LRRD and the hinge region, activating an "intramolecular agonistic unit" close to the transmembrane domain.

  9. Extended and structurally supported insights into extracellular hormone binding, signal transduction and organization of the thyrotropin receptor.

    Science.gov (United States)

    Krause, Gerd; Kreuchwig, Annika; Kleinau, Gunnar

    2012-01-01

    The hormone thyrotropin (TSH) and its receptor (TSHR) are crucial for the growth and function of the thyroid gland. The TSHR is evolutionary linked with the receptors of follitropin (FSHR) and lutropin/choriogonadotropin (LHR) and their sequences and structures are similar. The extracellular region of TSHR contains more than 350 amino acids and binds hormone and antibodies. Several important questions related to functions and mechanisms of TSHR are still not comprehensively understood. One major reason for these open questions is the lack of any structural information about the extracellular segment of TSHR that connects the N-terminal leucine-rich repeat domain (LRRD) with the transmembrane helix (TMH) 1, the hinge region. It has been shown experimentally that this segment is important for fine tuning of signaling and ligand interactions. A new crystal structure containing most of the extracellular hFSHR region in complex with hFSH has recently been published. Now, we have applied these new structural insights to the homologous TSHR and have generated a structural model of the TSHR LRRD/hinge-region/TSH complex. This structural model is combined and evaluated with experimental data including hormone binding (bTSH, hTSH, thyrostimulin), super-agonistic effects, antibody interactions and signaling regulation. These studies and consideration of significant and non-significant amino acids have led to a new description of mechanisms at the TSHR, including ligand-induced displacements of specific hinge region fragments. This event triggers conformational changes at a convergent center of the LRRD and the hinge region, activating an "intramolecular agonistic unit" close to the transmembrane domain.

  10. Integrating structural and mutagenesis data to elucidate GPCR ligand binding

    DEFF Research Database (Denmark)

    Munk, Christian; Harpsøe, Kasper; Hauser, Alexander S

    2016-01-01

    G protein-coupled receptors (GPCRs) represent the largest family of human membrane proteins, as well as drug targets. A recent boom in GPCR structural biology has provided detailed images of receptor ligand binding sites and interactions on the molecular level. An ever-increasing number of ligands...... elucidate new GPCR ligand binding sites, and ultimately design drugs with tailored pharmacological activity....

  11. Desktop NMR for structure elucidation and identification of strychnine adulteration.

    Science.gov (United States)

    Singh, Kawarpal; Blümich, Bernhard

    2017-05-02

    Elucidating the structure of complex molecules is difficult at low magnetic fields due to the overlap of different peak multiplets and second-order coupling effects. This is even more challenging for rigid molecules with small chemical shift differences and with prochiral centers. Since low-field NMR spectroscopy is sometimes presumed as restricted to the analysis of only small and simple molecules, this paper aims at countering this misconception: it demonstrates the use of low-field NMR spectroscopy in chemical forensics for identifying strychnine and its counterions by exploring the chemical shift as a signature in different 1D 1 H and 13 C experiments. Hereby the applied methodologies combine various 1D and 2D experiments such as 1D 1 H, 13 C, DEPT, and 2D COSY, HETCOR, HSQC, HMBC and J-resolved spectroscopy to elucidate the molecular structure and skeleton of strychnine at 1 Tesla. Strychnine is exemplified here, because it is a basic precursor in the chemistry of natural products and is employed as a chemical weapon and as a doping agent in sports including the Olympics. In our study, the molecular structure of the compound could be identified either with a 1D experiment at high magnetic field or with HMBC and HSQC experiments at 1 T. In conclusion, low-field NMR spectroscopy enables the chemical elucidation of the strychnine structure through a simple click with a computer mouse. In situations where a high-field NMR spectrometer is unavailable, compact NMR spectrometers can nevertheless generate knowledge of the structure, important for identifying the different chemical reaction mechanisms associated with the molecule. Desktop NMR is a cost-effective viable option in chemical forensics. It can prove adulteration and identify the origin of different strychnine salts, in particular, the strychnine free base, strychnine hemisulphate and strychnine hydrochloride. The chemical shift signatures report the chemical structure of the molecules due to the impact of

  12. Structure elucidation of a novel oligosaccharide (Medalose) from camel milk

    Science.gov (United States)

    Gangwar, Lata; Singh, Rinku; Deepak, Desh

    2018-02-01

    Free oligosaccharides are the third most abundant solid component in milk after lactose and lipids. The study of milk oligosaccharides indicate that nutrients are not only benefits the infant's gut but also perform a number of other functions which include stimulation of growth, receptor analogues to inhibit binding of pathogens and substances that promote postnatal brain development. Surveys reveal that camel milk oligosaccharides possess varied biological activities that help in the treatment of diabetes, asthma, anaemia, piles and also a food supplement to milking mothers. In this research, camel milk was selected for its oligosaccharide contents, which was then processed by Kobata and Ginsburg method followed by the HPLC and CC techniques. Structure elucidation of isolated compound was done by the chemical degradation, chemical transformation and comparison of chemical shift of NMR data of natural and acetylated oligosaccharide structure reporter group theory, the 1H, 13C NMR, 2D-NMR (COSY, TOCSY and HSQC) techniques, and mass spectrometry. The structure was elucidated as under: MEDALOSE

  13. Elucidation of Operon Structures across Closely Related Bacterial Genomes

    Science.gov (United States)

    Li, Guojun

    2014-01-01

    About half of the protein-coding genes in prokaryotic genomes are organized into operons to facilitate co-regulation during transcription. With the evolution of genomes, operon structures are undergoing changes which could coordinate diverse gene expression patterns in response to various stimuli during the life cycle of a bacterial cell. Here we developed a graph-based model to elucidate the diversity of operon structures across a set of closely related bacterial genomes. In the constructed graph, each node represents one orthologous gene group (OGG) and a pair of nodes will be connected if any two genes, from the corresponding two OGGs respectively, are located in the same operon as immediate neighbors in any of the considered genomes. Through identifying the connected components in the above graph, we found that genes in a connected component are likely to be functionally related and these identified components tend to form treelike topology, such as paths and stars, corresponding to different biological mechanisms in transcriptional regulation as follows. Specifically, (i) a path-structure component integrates genes encoding a protein complex, such as ribosome; and (ii) a star-structure component not only groups related genes together, but also reflects the key functional roles of the central node of this component, such as the ABC transporter with a transporter permease and substrate-binding proteins surrounding it. Most interestingly, the genes from organisms with highly diverse living environments, i.e., biomass degraders and animal pathogens of clostridia in our study, can be clearly classified into different topological groups on some connected components. PMID:24959722

  14. Elucidation of operon structures across closely related bacterial genomes.

    Science.gov (United States)

    Zhou, Chuan; Ma, Qin; Li, Guojun

    2014-01-01

    About half of the protein-coding genes in prokaryotic genomes are organized into operons to facilitate co-regulation during transcription. With the evolution of genomes, operon structures are undergoing changes which could coordinate diverse gene expression patterns in response to various stimuli during the life cycle of a bacterial cell. Here we developed a graph-based model to elucidate the diversity of operon structures across a set of closely related bacterial genomes. In the constructed graph, each node represents one orthologous gene group (OGG) and a pair of nodes will be connected if any two genes, from the corresponding two OGGs respectively, are located in the same operon as immediate neighbors in any of the considered genomes. Through identifying the connected components in the above graph, we found that genes in a connected component are likely to be functionally related and these identified components tend to form treelike topology, such as paths and stars, corresponding to different biological mechanisms in transcriptional regulation as follows. Specifically, (i) a path-structure component integrates genes encoding a protein complex, such as ribosome; and (ii) a star-structure component not only groups related genes together, but also reflects the key functional roles of the central node of this component, such as the ABC transporter with a transporter permease and substrate-binding proteins surrounding it. Most interestingly, the genes from organisms with highly diverse living environments, i.e., biomass degraders and animal pathogens of clostridia in our study, can be clearly classified into different topological groups on some connected components.

  15. Rufinamide: Crystal structure elucidation and solid state characterization.

    Science.gov (United States)

    Salunke, Nita; Thipparaboina, Rajesh; Chavan, Rahul B; Lodagekar, Anurag; Mittapalli, Sudhir; Nangia, Ashwini; Shastri, Nalini R

    2018-02-05

    Rufinamide (R) is a triazole derivative approved for the management of partial seizures and seizures associated with Lennox-Gastaut Syndrome, in November 2007. Crystal structure, solid state characterization, drug-excipient compatibility and solubility play a pivotal role in formulation development. This work deals with the crystal structure elucidation of R by single crystal X-ray diffraction and solid state characterization by thermal, spectroscopic and crystallographic techniques. Drug- excipient compatibility was assessed by differential scanning calorimetry (DSC). New RP-HPLC method for quantification of R was developed with improved retention time. Solubility and dissolution of drug in different media was determined. Additionally, the flow behavior of the drug was evaluated by measuring Carr's index and Hausner's ratio, while the compressibility behavior was studied using Well's protocol. R crystallized from dimethylformamide (R-DMF) was utilized for single crystal analysis. The drug crystallized in triclinic crystal system with P-1 space group. Asymmetric unit cell consists of two molecules of R held by intermolecular hydrogen bond (connected by NH⋯O, which forms the catemeric chain). Analytical outcomes from DSC, thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD) revealed that the drug was present in pure crystalline form and was devoid of any polymorphic or pseudopolymorphic impurities. Influence of pH on the solubility and dissolution of R-DMF was found to be insignificant. The drug exhibited poor aqueous solubility, which was improved nearly 4.6 fold with the addition of 2% sodium lauryl sulphate (SLS). The drug exhibits poor flow and elastic compression nature. Excipients such as poly ethylene glycol (PEG) 8000, SLS, lactose monohydrate, starch and Hydroxypropyl methylcellulose (HPMC) E15 were incompatible with R-DMF as identified by thermal analysis. It is envisaged that these information regarding solid state properties of R

  16. Structure elucidation of two neurotoxins from Albizia tanganyicensis

    International Nuclear Information System (INIS)

    Steyn, P.S.; Vleggaar, R.

    1987-01-01

    The structures of two neurotoxins isolated from Albizia tanganyicensis were determined by application of 1 H and 13 C n.m.r. spectroscopy as 3-hydroxy-5-hydroxymethyl-4-methoxymethyl-2-methylpyridine and the 5-acetoxymethyl derivative respectively

  17. Marine natural products : integrated spectroscopic solutions for structure elucidation

    OpenAIRE

    Morinaka, Brandon Isamu

    2011-01-01

    This dissertation describes the structure determination and biological activity of four groups of sponge derived secondary metabolites by integrated approaches using synthesis and circular dichroism. Chapter 2 describes the isolation and structure determination of brominated ene- yne tetrahydrofuran fatty acids, mutafurans A-G from the marine sponge Xestospongia muta. Two optically active ene- yne tetrahydrofuran model compounds were synthesized for chiroptical comparison to the natural produ...

  18. Elucidation of mechanism wear carbon steel with structure of martensite

    Directory of Open Access Journals (Sweden)

    I. A. Vakulenko

    2013-04-01

    Full Text Available Purpose. The purpose of the paper is an estimation of degree of metal hardness change for the railway wheel with martensite structure during rolling. Methodology. As strength characteristic the Rockwell hardness is used. Wear tests were conducted in the conditions of normal loading with (10% and without sliding on the test equipment SMTs-2. Parameters of the fine crystalline structure (tetragonality degree of the crystalline grid, dislocation density, scale of coherent scattering regions, and disturbance value of the crystalline grid of second kind are determined by the methods of X-ray structural analysis. Findings. During operation of the railway wheels with different strength level, origin of defects on the wheel thread is caused by simultaneous action of both the friction forces and the cyclically changing loadings. Considering that formation of damage centers is largely determined by the state of metal volumes near the wheel thread, one should expect the differences in friction processes development at high contact stress for the wheels with different strength level and structural state. Originality. During the wear tests softening effect of carbon steel with martensite quenching structure is obtained. Softening effect equaled 3.5–7% from the level of quenched metal hardness. The softening effect is accompanied by the reduction of tetragonality degree of the crystalline structure of martensite, reduction of coherent scattering regions, dislocation density increase and crystalline grid disturbance of the second kind. Practical value. The results point out the necessity for further studies to clarify the resulted softening effect mechanism.

  19. Elucidating the Vacuum Structure of the Aoki Phase

    OpenAIRE

    Azcoiti, Vicente; Di Carlo, Giuseppe; Follana, Eduardo; Vaquero, Alejandro

    2012-01-01

    In this paper, we discuss the vacuum structure of QCD with two flavors of Wilson fermions, inside the Aoki phase. We provide numerical evidence, coming from HMC simulations in $4^4$, $6^4$ and $8^4$ lattices, supporting a vacuum structure for this model at strong coupling more complex than the one assumed in the standard wisdom, with new vacua where the expectation value of $i\\bar\\psi\\gamma_5\\psi$ can take non-zero values, and which can not be connected with the Aoki vacua by parity-flavour s...

  20. Isolation and structure elucidation of a neuropeptide from three ...

    African Journals Online (AJOL)

    1993-03-03

    Mar 3, 1993 ... the compounds for all three species were identical. Amino acid composition data. in combination ... enzymically deblocking the N-terminal pyroglutamate residue, reveals an identical octapeptide for the three investigated species: .... was used for obtaining structural information. Amino acid composition data ...

  1. Collision-Induced Dissociation Mass Spectrometry: A Powerful Tool for Natural Product Structure Elucidation.

    Science.gov (United States)

    Johnson, Andrew R; Carlson, Erin E

    2015-11-03

    Mass spectrometry is a powerful tool in natural product structure elucidation, but our ability to directly correlate fragmentation spectra to these structures lags far behind similar efforts in peptide sequencing and proteomics. Often, manual data interpretation is required and our knowledge of the expected fragmentation patterns for many scaffolds is limited, further complicating analysis. Here, we summarize advances in natural product structure elucidation based upon the application of collision induced dissociation fragmentation mechanisms.

  2. NMR spectroscopy: structure elucidation of cycloelatanene A: a natural product case study.

    Science.gov (United States)

    Urban, Sylvia; Dias, Daniel Anthony

    2013-01-01

    The structure elucidation of new secondary metabolites derived from marine and terrestrial sources is frequently a challenging task. The hurdles include the ability to isolate stable secondary metabolites of sufficient purity that are often present in products that the compound may rapidly degrade during and/or after the isolation, due to sensitivity to light, air oxidation, and/or temperature. In this way, precautions need to be taken, as much as possible to avoid any such chemical inter-conversions and/or degradations. Immediately after purification, the next step is to rapidly acquire all analytical spectroscopic data in order to complete the characterization of the isolated secondary metabolite(s), prior to any possible decomposition. The final hurdle in this multiple step process, especially in the acquisition of the NMR spectroscopic and other analytical data (mass spectra, infrared and ultra-violet spectra, optical rotation, etc.), is to assemble the structural moieties/units in an effort to complete the structure elucidation. Often ambiguity with the elucidation of the final structure remains when structural fragments identified are difficult to piece together on the basis of the HMBC NMR correlations or when the relative configuration cannot be unequivocally identified on the basis of NOE NMR enhancements observed. Herein, we describe the methodology used to carry out the structure elucidation of a new C16 chamigrene, cycloelatanene A (5) which was isolated from the southern Australian marine alga Laurencia elata (Rhodomelaceae). The general approach and principles used in the structure determination of this compound can be applied to the structure elucidation of other small molecular weight compounds derived from either natural or synthetic sources.

  3. Separation and structure elucidation of a new homoflavanol derivative from Pteridium aquilinum (L.) Kuhn.

    Science.gov (United States)

    Chen, Nai-Dong; Chen, Nai-Fu; Chen, Cun-Wu; Zhang, Li

    2013-01-01

    A novel homoflavanol derivative (1) with an unprecedented skeleton, as well as two known flavonoids kaempferol (2) and quercetin (3), was isolated from the plant Pteridium aquilinum (L.) Kuhn, and the structure and relative stereochemistry of the new compound (1) were elucidated on the basis of spectroscopic data.

  4. Nature's Migraine Treatment: Isolation and Structure Elucidation of Parthenolide from "Tanacetum parthenium"

    Science.gov (United States)

    Walsh, Emma L.; Ashe, Siobhan; Walsh, John J.

    2012-01-01

    The purpose of this experiment is to provide students with the essential skills and knowledge required to perform the extraction, isolation, and structural elucidation of parthenolide from "Tanacetum parthenium" or feverfew. Students are introduced to a background of the traditional medicinal uses of parthenolide, while more modern applications of…

  5. Structure Elucidation and Cytotoxic Evaluation of New Polyacetylenes from a Marine Sponge Petrosia sp.

    Directory of Open Access Journals (Sweden)

    Yung-Shun Juan

    2014-09-01

    Full Text Available The sponge Petrosia sp. yielded five polyacetylenic compounds (1–5, including two new polyacetylenes, petrosianynes A (1 and B (2. The structures of these compounds were elucidated by detailed spectroscopic analysis and by comparison with the physical and spectral data of related known analogues. Compounds 1–5 exhibited significant cytotoxic activity against a limited panel of cancer cell lines.

  6. General scheme for elucidating the structure of organic compounds using spectroscopic and spectrometric methods

    International Nuclear Information System (INIS)

    Ribeiro, Carlos Magno R.; Souza, Nelson Angelo de

    2007-01-01

    This work describes a systematic method to be applied in undergraduate courses of organic chemistry, correlating infrared spectra, hydrogen and carbon-13 nuclear magnetic resonance, and mass spectra. To this end, a scheme and a table were developed to conduct the elucidation of the structure of organic compounds initially using infrared spectra. Interpretation of hydrogen and carbon-13 nuclear magnetic resonance spectra and of mass spectra is used to confirm the proposed structure. (author)

  7. Catalog-library approach for the rapid and sensitive structural elucidation of oligosaccharides.

    Science.gov (United States)

    Tseng, K; Hedrick, J L; Lebrilla, C B

    1999-09-01

    We obtained the nearly complete structural elucidation of oligosaccharide components, including sequence, linkage, and even stereochemistry in the picomolar levels. The "catalog-library" approach is used for elucidating the structures of minor components in a mixture of oligosaccharides. Oligosaccharides released from a family of glycoproteins are often composed of a small finite set of monosaccharides. In this regard, the numerous oligosaccharide species are analogous to the products found in syntheses involving combinatorial libraries. The great structural diversity in the library is the result of the nearly infinite combinations in which even a small number of monosaccharides can be arranged. Fortunately, structural similarities exist between different oligosaccharides, as specific substructural motifs are preserved among different compounds. We propose that a catalog of substructural motifs can be identified and characterized by collision-induced dissociation mass spectrometry. The catalog is constructed from a set of known compounds that have been fully structurally elucidated by, for example, nuclear magnetic resonance. The catalog consists of the characteristic fragmentation patterns belonging to a set of specific substructural motifs. Collision-induced dissociation is used to determine the presence of these motifs and reconstruct the structures of less abundant components.

  8. Structural elucidation of an antibiotic from the fungus Fusarium avenaceum Fries Sacc.; an amended structure for lateropyrone

    International Nuclear Information System (INIS)

    Gorst-Allman, C.P.; Van Rooyen, P.H.; Wnuk, S.; Golinski, P.; Chelkowski, J.

    1986-01-01

    The structural elucidation by X-ray crystallography of an antibiotic produced by Fusarium avenaceum Fries Sacc. is described. Some chemical reactions of the metabolite are reported, and the identity of the metabolite with lateropyrone is proposed. The structure reported for lateropyrone is amended. 1 H n.m.r. and 13 C n.m.r. are used in this study

  9. Mass spectra-based framework for automated structural elucidation of metabolome data to explore phytochemical diversity

    Directory of Open Access Journals (Sweden)

    Fumio eMatsuda

    2011-08-01

    Full Text Available A novel framework for automated elucidation of metabolite structures in liquid chromatography-mass spectrometer (LC-MS metabolome data was constructed by integrating databases. High-resolution tandem mass spectra data automatically acquired from each metabolite signal were used for database searches. Three distinct databases, KNApSAcK, ReSpect, and the PRIMe standard compound database, were employed for the structural elucidation. The outputs were retrieved using the CAS metabolite identifier for identification and putative annotation. A simple metabolite ontology system was also introduced to attain putative characterization of the metabolite signals. The automated method was applied for the metabolome data sets obtained from the rosette leaves of 20 Arabidopsis accessions. Phenotypic variations in novel Arabidopsis metabolites among these accessions could be investigated using this method.

  10. Hünlich base: (re)discovery, synthesis, and structure elucidation after a century.

    Science.gov (United States)

    Rigol, Stephan; Beyer, Lothar; Hennig, Lothar; Sieler, Joachim; Giannis, Athanassios

    2013-03-15

    After almost 100 years, the structure of the product of the reaction between 2,4-diaminotoluene and formaldehyde was elucidated: derivative 3, which we call the Hünlich base, was synthesized on a multigram scale and its enantiomers were easily separated in preparative amounts. Furthermore, transformation of the NH2 groups to the corresponding bis-iodides and bis-azides is presented. The latter was also used for desymmetrization by click chemistry.

  11. New improvements in automatic structure elucidation using the LSD (Logic for Structure Determination) and the SISTEMAT expert systems.

    Science.gov (United States)

    Plainchont, Bertrand; Nuzillard, Jean-Marc; Rodrigues, Gilberto V; Ferreira, Marcelo J P; Scotti, Marcus T; Emerenciano, Vicente P

    2010-05-01

    This article describes the integration of the LSD (Logic for Structure Determination) and SISTEMAT expert systems that were both designed for the computer-assisted structure elucidation of small organic molecules. A first step has been achieved towards the linking of the SISTEMAT database with the LSD structure generator. The skeletal descriptions found by the SISTEMAT programs are now easily transferred to LSD as substructural constraints. Examples of the synergy between these expert systems are given for recently reported natural products.

  12. A Comprehensive Review of the Structure Elucidation and Biological Activity of Triterpenoids from Ganoderma spp.

    Directory of Open Access Journals (Sweden)

    Qing Xia

    2014-10-01

    Full Text Available Ganoderma triterpenes (GTs are the major secondary metabolites of Ganoderma lucidum, a traditional Chinese medicine, popularly used for complementary cancer therapy. GTs are lanostane-tetracyclic triterpenes. They have been reported to possess anti-tumor, anti-inflammation, antioxidant, antimicrobial and blood fat reducing effects. To date, 316 GTs have been found and their similar chemical structures have proved difficult to elucidate. This paper compiles 316 naturally occurring triterpenes from Ganoderma based on the literature published through January 2013 along with their structures, physiological activities and 13C-NMR spectral data.

  13. Computer-assisted methods for molecular structure elucidation: realizing a spectroscopist's dream

    Directory of Open Access Journals (Sweden)

    Elyashberg Mikhail

    2009-03-01

    Full Text Available Abstract Background This article coincides with the 40 year anniversary of the first published works devoted to the creation of algorithms for computer-aided structure elucidation (CASE. The general principles on which CASE methods are based will be reviewed and the present state of the art in this field will be described using, as an example, the expert system Structure Elucidator. Results The developers of CASE systems have been forced to overcome many obstacles hindering the development of a software application capable of drastically reducing the time and effort required to determine the structures of newly isolated organic compounds. Large complex molecules of up to 100 or more skeletal atoms with topological peculiarity can be quickly identified using the expert system Structure Elucidator based on spectral data. Logical analysis of 2D NMR data frequently allows for the detection of the presence of COSY and HMBC correlations of "nonstandard" length. Fuzzy structure generation provides a possibility to obtain the correct solution even in those cases when an unknown number of nonstandard correlations of unknown length are present in the spectra. The relative stereochemistry of big rigid molecules containing many stereocenters can be determined using the StrucEluc system and NOESY/ROESY 2D NMR data for this purpose. Conclusion The StrucEluc system continues to be developed in order to expand the general applicability, provide improved workflows, usability of the system and increased reliability of the results. It is expected that expert systems similar to that described in this paper will receive increasing acceptance in the next decade and will ultimately be integrated directly to analytical instruments for the purpose of organic analysis. Work in this direction is in progress. In spite of the fact that many difficulties have already been overcome to deliver on the spectroscopist's dream of "fully automated structure elucidation" there is

  14. Tannin structural elucidation and quantitative ³¹P NMR analysis. 1. Model compounds.

    Science.gov (United States)

    Melone, Federica; Saladino, Raffaele; Lange, Heiko; Crestini, Claudia

    2013-10-02

    Tannins and flavonoids are secondary metabolites of plants that display a wide array of biological activities. This peculiarity is related to the inhibition of extracellular enzymes that occurs through the complexation of peptides by tannins. Not only the nature of these interactions, but more fundamentally also the structure of these heterogeneous polyphenolic molecules are not completely clear. This first paper describes the development of a new analytical method for the structural characterization of tannins on the basis of tannin model compounds employing an in situ labeling of all labile H groups (aliphatic OH, phenolic OH, and carboxylic acids) with a phosphorus reagent. The ³¹P NMR analysis of ³¹P-labeled samples allowed the unprecedented quantitative and qualitative structural characterization of hydrolyzable tannins, proanthocyanidins, and catechin tannin model compounds, forming the foundations for the quantitative structural elucidation of a variety of actual tannin samples described in part 2 of this series.

  15. Hydrogen/deuterium exchange in electrospray ionization mass spectrometry as a practical tool for structure elucidation

    International Nuclear Information System (INIS)

    Conboy, J.J.; Bean, M.F.; Hemling, M.E.; Carr, S.A.

    1993-01-01

    Measurement of the number of active hydrogens in a molecule by various types of hydrogen/deuterium exchange experiments has for a number of years proven useful in the elucidation of compounds of unknown structure, in the determination of the mechanism of chemical or biological reactions, and in the interpretation of fragmentation pathways in mass spectra. Recent work in the analysis of protein conformation by ESIMS has made use of both solution phase and gas phase (atmospheric pressure or in vacuo) hydrogen/deuterium exchange methods. The gas phase exchange experiments were performed either on FTMS instrumentation to achieve the long residence times required for exchange or with a heated dual-capillary inlet reactor interface for desolvation and then exchange of the sample molecules. The authors have implemented methods for hydrogen/deuterium exchange which require only simple changes to the plumbing of a Sciex API-III Ionspray source. Effective exchange of active hydrogens may be achieved by replacing either all of the nebulizer gas or part of the curtain gas or both with a deuterated exchange agent such as ND 3 . These methods provide for essentially complete exchange of all active hydrogens on the types of small molecules (e.g., alkaloids, glycosides, etc.) for which H/D exchange has been of proven utility in structure elucidation work; larger molecules, or at least those with a large number of potentially exchangeable hydrogens, proved to be more challenging particularly in regard to completeness of exchange. These methods also appear to work without the need for dissolving the sample in deuterated or aprotic solvents. A simple ESIMS H/D exchange experiment is a useful addition to the mass spectrometrist's armamentarium for the elucidation of unknown structures. With it, H/D exchange is now extended to classes of compounds not amenable to FAB or DCI, especially in cases where sample is limited

  16. Structural elucidation of metolachlor photoproducts by liquid chromatography/high-resolution tandem mass spectrometry.

    Science.gov (United States)

    Nicol, Édith; Genty, Christophe; Bouchonnet, Stéphane; Bourcier, Sophie

    2015-12-15

    Metolachlor is one of the most intensively used chloroacetanilide herbicides in agriculture. It has been detected in water; consequently, under UV-visible irradiation, it can be transformed in degradation products (TPs). The structures of TPs were elucidated by liquid chromatography/high-resolution tandem mass spectrometry (LC/HR-MS/MS). The potential toxicities of these TPs were estimated by in silico tests. Aqueous solutions of metolachlor were irradiated in a self-made reactor equipped with a mercury vapor lamp. Analyses were carried out using high-performance liquid chromatography coupled to quadrupole time-of-flight (QTOF) mass spectrometer. High-resolution m/z measurements, MS/MS and isotopic labeling experiments allowed structural elucidation of metolachlor TPs. Their toxicities were estimated in silico, using the T.E.S.T. Ten major metolachlor photoproducts were characterized by LC/MS/MS after irradiation of metolachlor in aqueous solution. Elucidation of their chemical structures was identified using high-resolution measurements and MS/MS experiments. They resulted from the combination of dehalogenation, hydroxylation and cyclisation processes. The potential oral rat lethal dose (LD50) was assessed with QSAR tests for metolachlor and each photoproduct. Results indicate that most of the TPs are much more toxic than metolachlor. UV-vis irradiation of metolachlor in aqueous solution leads to the formation of ten photoproducts. QSAR estimations show that the location of added hydroxyl group(s) is of key relevance as regards to biological activity and that routine water analysis should take into account the TPs are more toxic than the parent molecule. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Clinical evaluation of thyrotropin-releasing hormone (TRH) test with a sensitive immunoradiometric thyrotropin (TSH) assay kit

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Saeko; Demura, Reiko; Yamanaka, Yukako; Ishiwatari, Naoko; Jibiki, Kazuko; Odagiri, Emi; Demura, Hiroshi

    1987-10-01

    Thyrotropin-releasing hormone (TRH) test was performed using a commercially available immunoradiometric thyrotropin (TSH) assay kit (RIA-gnost hTSH) in patients with endocrine diseases. The basal serum concentration of TSH ranged from 0.2 to 2.9 ..mu..U/ml in healthy subjects. The values for endocrine diseases, except for Graves' disease, were almost within the normal range. A significant increase in TSH values caused by TRH test was observed in females compared with males (4.4 - 24.7 ..mu..U/ml vs 4.1 - 12.3 ..mu..U/ml). In cases of Graves' disease, there was a good correlation between the basal TSH value and the response of TSH to TRH. However, in the other endocrine diseases, including acromegaly, prolactinoma, anorexia nervosa, Cushing syndrome, and hypopituitarism, the response of TSH to TRH did not necessarily correlated with the basal TSH value. TRH test would be of value in elucidating pathophysiologic features, as well as in accurately diagnosing secretion reserve of TSH. (Namekawa, K.).

  18. Clinical evaluation of thyrotropin-releasing hormone (TRH) test with a sensitive immunoradiometric thyrotropin (TSH) assay kit

    International Nuclear Information System (INIS)

    Nakamura, Saeko; Demura, Reiko; Yamanaka, Yukako; Ishiwatari, Naoko; Jibiki, Kazuko; Odagiri, Emi; Demura, Hiroshi

    1987-01-01

    Thyrotropin-releasing hormone (TRH) test was performed using a commercially available immunoradiometric thyrotropin (TSH) assay kit (RIA-gnost hTSH) in patients with endocrine diseases. The basal serum concentration of TSH ranged from 0.2 to 2.9 μU/ml in healthy subjects. The values for endocrine diseases, except for Graves' disease, were almost within the normal range. A significant increase in TSH values caused by TRH test was observed in females compared with males (4.4 - 24.7 μU/ml vs 4.1 - 12.3 μU/ml). In cases of Graves' disease, there was a good correlation between the basal TSH value and the response of TSH to TRH. However, in the other endocrine diseases, including acromegaly, prolactinoma, anorexia nervosa, Cushing syndrome, and hypopituitarism, the response of TSH to TRH did not necessarily correlated with the basal TSH value. TRH test would be of value in elucidating pathophysiologic features, as well as in accurately diagnosing secretion reserve of TSH. (Namekawa, K.)

  19. Dihydronaflavonols from the leaves of Derris urucu (Leguminosae): structural elucidation and DPPH radical-scavenging activity

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, Livia T.; Silva, Geilson A. da; Ferreira, Malisson; Silva, Milton N. da; Santos, Alberdan S.; Arruda, Alberto C.; Guilhon, Gisele M.S.P.; Santos, Lourivaldo S.; Arruda, Mara Silvia P. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Ciencias Exatas e Naturais. Programa de Pos-Graduacao em Quimica], e-mail: mspa@ufpa.br; Borges, Rosilvaldo dos Santos [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Fac. de Farmacia. Inst. de Ciencias

    2009-07-01

    Derris urucu is an Amazonian plant with insecticide and ichthyotoxic properties. Studies with this species show the presence of flavonoids, mainly rotenoids, as well as stilbenes. The ethanol extract of the leaves of Derris urucu (Leguminosae) afforded three new dihydroflavonols named urucuol A (1), B (2) and C (3), and the dihydroflavonol isotirumalin (4). Their structures were elucidated by extensive analysis of 1D and 2D NMR, UV and IR spectra and MS data and comparison with literature data. The isolated compounds (1-4) were evaluated for DPPH radical scavenging activity and showed a relatively lower antioxidant ability compared to the commercial antioxidant trans-resveratrol. (author)

  20. Isolation and Structural Elucidation of an Unknown compound from Murraya alternans (Kurz)Swingle

    International Nuclear Information System (INIS)

    Mya Aye; Hla Myoe Min; Sein Htun

    2002-02-01

    A new taxon of a species, Murraya alternans (Kurz) Swingle (Myanmar name, Naganaing) the series of Murraya belonging to the family Rutaceae had been recognized by Peter G. Waterman in 1986. However, this species has not been undertaken in botanical, medical, and chemical aspects. In this paper, scientific study on this taxon was chemically carried out for the first time. One of the unknown compounds was isolated from this species by column and high performance liquid chromatographic methods. It's partial structure could also be elucidated by spectral analysis such as IR, MS, H NMR(400MHz), C NMR (100MHz) spectrometry respectively. (author)

  1. Structure elucidation of five new iridoid glucosides from the leaves of Avicennia marina.

    Science.gov (United States)

    Sun, Yu; Ouyang, Jie; Deng, Zhiwei; Li, Qingshan; Lin, Wenhan

    2008-07-01

    A chemical examination of the mangrove plant Avicennia marina (Forrsk.) Vierh resulted in the isolation and characterization of five new iridoids, marinoids A-E (1-5), along with 2'-cinnamoyl-mussaenosidic acid (6), 2'-O-(4''-methoxycinnamoyl) mussaenosidic acid (7), 2'-O-(4''-hydroxycinnamoyl) mussaenosidic acid (8), and 3(R)-hydroxy-5-phenyl-4(E)-pentenoic acid (9). The structures of 1-5 were elucidated on the basis of 1D and 2D NMR (COSY, HMQC, HMBC, and NOESY) in association with IR and MS data analysis. Copyright (c) 2008 John Wiley & Sons, Ltd.

  2. Isolation and structure elucidation of cytotoxic polyacetylenes and polyenes from Echinacea pallida.

    Science.gov (United States)

    Pellati, Federica; Calò, Samuele; Benvenuti, Stefania; Adinolfi, Barbara; Nieri, Paola; Melegari, Michele

    2006-07-01

    Bioassay-guided fractionation of n-hexane extracts of Echinacea pallida (Asteraceae) roots led to the isolation and structure elucidation of two polyacetylenes (1, 3) and three polyenes (2, 4, 5). Two are known hydroxylated compounds, namely 8-hydroxy-pentadeca-(9E)-ene-11,13-diyn-2-one (1) and 8-hydroxy-pentadeca-(9E,13Z)-dien-11-yn-2-one (2). Two dicarbonylic constituents, namely pentadeca-(9E)-ene-11,13-diyne-2,8-dione (3) and pentadeca-(9E,13Z)-dien-11-yne-2,8-dione (4), were isolated and characterized for the first time. Furthermore, the structure elucidation of pentadeca-(8Z,13Z)-dien-11-yn-2-one (5) is described. The structure of the compounds isolated was determined on the basis of UV, IR, NMR (including 1D and 2D NMR experiments, such as 1H-1H gCOSY, gHSQC-DEPT, gHMBC, gNOESY) and MS spectroscopic data. The cytotoxic activity of the isolated constituents against MIA PaCa-2 human pancreatic adenocarcinoma cells was evaluated in the concentration range 1-100 microg/ml. Results show that the hydroxylated compounds (1, 2) have low cytotoxicity, while the more hydrophobic polyacetylenes (3) and polyenes (4, 5) displayed moderate activity.

  3. Predictive and Experimental Approaches for Elucidating Protein–Protein Interactions and Quaternary Structures

    Directory of Open Access Journals (Sweden)

    John Oliver Nealon

    2017-12-01

    Full Text Available The elucidation of protein–protein interactions is vital for determining the function and action of quaternary protein structures. Here, we discuss the difficulty and importance of establishing protein quaternary structure and review in vitro and in silico methods for doing so. Determining the interacting partner proteins of predicted protein structures is very time-consuming when using in vitro methods, this can be somewhat alleviated by use of predictive methods. However, developing reliably accurate predictive tools has proved to be difficult. We review the current state of the art in predictive protein interaction software and discuss the problem of scoring and therefore ranking predictions. Current community-based predictive exercises are discussed in relation to the growth of protein interaction prediction as an area within these exercises. We suggest a fusion of experimental and predictive methods that make use of sparse experimental data to determine higher resolution predicted protein interactions as being necessary to drive forward development.

  4. Isolation and structural elucidation of secondary metabolites of plants of the families asteraceae and urticaceae

    International Nuclear Information System (INIS)

    Villagra Quesada, E.

    2002-01-01

    A phytochemistry study of plant's species of the Asteraceae and Urticaceae family is proposed in order to isolate and to elucidate the structure of active principles; due to the fact that several studies have found that some of these families have compounds with anti-inflammatory activity, mainly lactonas sesquiterpenicas . The phytochemistry study was carried out through the application of chromatography techniques, for the separation and purification of the compounds. Includes chromatography of column, fine and liquid layer of high resolution. On the other hand, spectroscopic techniques were used for the elucidation, mainly of nuclear magnetic resonance (RMN) as much of one as of two dimensions. In this way, it was possible to isolate 14 compounds in Decachaeta thieleana and 10 in Phenax mexicanus, from which 6 correspond compounds of innovative structure. The comparison of the results obtained in Decachaeta thieleana (with previous studies) evidences that specimens, orphologically identical (the same species, but different locations), possess totally different compounds. This suggests that the studied specimens do not correspond to the same species. However, the determination of such a cause not only evade the objectives of this work but also the area of study of Chemistry [es

  5. Structure Elucidation of Unknown Metabolites in Metabolomics by Combined NMR and MS/MS Prediction.

    Science.gov (United States)

    Boiteau, Rene M; Hoyt, David W; Nicora, Carrie D; Kinmonth-Schultz, Hannah A; Ward, Joy K; Bingol, Kerem

    2018-01-17

    We introduce a cheminformatics approach that combines highly selective and orthogonal structure elucidation parameters; accurate mass, MS/MS (MS²), and NMR into a single analysis platform to accurately identify unknown metabolites in untargeted studies. The approach starts with an unknown LC-MS feature, and then combines the experimental MS/MS and NMR information of the unknown to effectively filter out the false positive candidate structures based on their predicted MS/MS and NMR spectra. We demonstrate the approach on a model mixture, and then we identify an uncatalogued secondary metabolite in Arabidopsis thaliana . The NMR/MS² approach is well suited to the discovery of new metabolites in plant extracts, microbes, soils, dissolved organic matter, food extracts, biofuels, and biomedical samples, facilitating the identification of metabolites that are not present in experimental NMR and MS metabolomics databases.

  6. Isolation, structure elucidation and total synthesis of a cytotoxic dienone from Echinacea pallida.

    Science.gov (United States)

    Morandi, Stefania; Pellati, Federica; Ori, Claudia; Adinolfi, Barbara; Nieri, Paola; Benvenuti, Stefania; Prati, Fabio

    2008-12-07

    The isolation and structure characterization of a dienone from the roots of Echinacea pallida, namely (8Z,11Z)-pentadeca-8,11-dien-2-one, are described here. To assess the configuration of this secondary metabolite, the stereoselective total synthesis of the two isomeric forms, (8Z,11Z)- and (8Z,11E)-pentadeca-8,11-dien-2-one, was undertaken and the structure elucidation of the natural compound was unambiguously carried out. The cytotoxic activity of both isomers was also evaluated on a human T cell leukaemia cancer line (Jurkat cells). The results indicated that these compounds exert a dose-dependent cytotoxicity with a medium-level potency on the tested cell line.

  7. Structural elucidation of humulone autoxidation products and analysis of their occurrence in stored hops.

    Science.gov (United States)

    Taniguchi, Yoshimasa; Taniguchi, Harumi; Matsukura, Yasuko; Kawachi, Yasuji; Shindo, Kazutoshi

    2014-06-27

    The transformation of α-acids [in hops (Humulus lupulus L.)] to iso-α-acids (in beer) during the brewing process is well known, but the occurrence and structure of the oxidized α-acids during hop storage are not well documented. Because an understanding of these oxidized compounds is essential to optimize the effects of oxidized hops on the quality of beer, we investigated the autoxidation products of humulone (a representative congener of α-acids) using a simplified autoxidation model. Among the oxidation products, tricyclooxyisohumulones A (1) and B (2), tricycloperoxyisohumulone A (3), deisopropyltricycloisohumulone (4), and the hemiacetal 5 of tricycloperoxyhumulone A (5') were isolated, and their structures were elucidated for the first time. The occurrence of compounds 1-4 in stored hops was verified using LC/MS/MS analysis. We also monitored the levels of compounds 1-4 during hop storage using LC/MS/MS analysis.

  8. The Crystal Structure of the Malaria Pigment Hemozoin as Elucidated by X-ray Powder Diffraction

    DEFF Research Database (Denmark)

    Straasø, Tine

    in the eradication of malaria. This thesis is a step towards that goal. When examining red blood cells from an infected person under a microscope dark pigment is observed. This dark pigment is actually small crystals called hemozoin. Hemozoin is a by-product formed by the parasite and a necessity for parasitic......Malaria is a widespread and severe disease caused by an infection by the parasite of the genus Plasmodium, the lifecycle of which is very complex. During its lifecycle the parasite resides in both a mosquito and a human host. If this cycle can be disrupted at any point, it will result...... survival. Successful inhibition of hemozoin crystallization will lead to parasitic death and thus break the cycle. The aim of this thesis is to elucidate the structure of hemozoin by means of X-ray diffraction techniques. Knowledge of the structure will help facilitate intelligent drug design in the future...

  9. Comprehensive secondary structure elucidation of four genera of the family Pospiviroidae.

    Directory of Open Access Journals (Sweden)

    Tamara Giguère

    Full Text Available Viroids are small, circular, single stranded RNA molecules that infect plants. Since they are non-coding, their structures play a critical role in their life cycles. To date, little effort has been spend on elucidating viroid structures in solution due to both the experimental difficulties and the time-consuming nature of the methodologies implicated. Recently, the technique of high-throughput selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE was adapted for the probing of the members of family Avsunviroidae, all of whom replicate in the chloroplast and demonstrate ribozyme activity. In the present work, twelve viroid species belonging to four different genera of the family Pospiviroidae, whose members are characterized by the presence of a central conserved region (CCR and who replicate in nucleus of the host, were probed. Given that the structures of five distinct viroid species from the family Pospiviroidae have been previously reported, an overview of the different structural characteristics for all genera and the beginning of a manual classification of the different viroids based on their structural features are presented here.

  10. Streamlined structure elucidation of an unknown compound in a pigment formulation.

    Science.gov (United States)

    Yüce, Imanuel; Morlock, Gertrud E

    2016-10-21

    A fast and reliable quality control is important for ink manufacturers to ensure a constant production grade of mixtures and chemical formulations, and unknown components attract their attention. Structure elucidating techniques seem time-consuming in combination with column-based methods, but especially the low solubility of pigment formulations is challenging the analysis. In contrast, layer chromatography is more tolerant with regard to pigment particles. One PLC plate for NMR and FTIR analyses and one HPTLC plate for recording of high resolution mass spectra, MS/MS spectra and for gathering information on polarity and spectral properties were needed to characterize a structure, exemplarily shown for an unknown component in pigment Red 57:1 to be 3-hydroxy-2-naphtoic acid. A preparative layer chromatography (PLC) workflow was developed that used an Automated Multiple Development 2 (AMD 2) system. The 0.5-mm PLC plate could still be operated in the AMD 2 system and allowed a smooth switch from the analytical to the preparative gradient separation. Through automated gradient development and the resulting focusing of bands, the sharpness of the PLC bands was improved. For NMR, the necessary high load of the target compound on the PLC plate was achieved via a selective solvent extraction that discriminated the polar sample matrix and thus increased the application volume of the extract that could maximally be applied without overloading. By doing so, the yield for NMR analysis was improved by a factor of 9. The effectivity gain through a simple, but thoroughly chosen extraction solvent is often overlooked, and for educational purpose, it was clearly illustrated and demonstrated by an extended solvent screening. Thus, PLC using an automated gradient development after a selective extraction was proven to be a new powerful combination for structural elucidation by NMR. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Structure Elucidation and Immunomodulatory Activity of A Beta Glucan from the Fruiting Bodies of Ganoderma sinense

    Science.gov (United States)

    Yue, Rui-Qi; Dong, Cai-Xia; Chan, Chung-Lap; Ko, Chun-Hay; Cheung, Wing-Shing; Luo, Ke-Wang; Dai, Hui; Wong, Chun-Kwok; Leung, Ping-Chung; Han, Quan-Bin

    2014-01-01

    A polysaccharide named GSP-2 with a molecular size of 32 kDa was isolated from the fruiting bodies of Ganoderma sinense. Its structure was well elucidated, by a combined utilization of chemical and spectroscopic techniques, to be a β-glucan with a backbone of (1→4)– and (1→6)–Glcp, bearing terminal- and (1→3)–Glcp side-chains at O-3 position of (1→6)–Glcp. Immunological assay exhibited that GSP-2 significantly induced the proliferation of BALB/c mice splenocytes with target on only B cells, and enhanced the production of several cytokines in human peripheral blood mononuclear cells and derived dendritic cells. Besides, the fluorescent labeled GSP-2 was phagocytosed by the RAW 264.7 cells and induced the nitric oxide secretion from the cells. PMID:25014571

  12. Structural elucidation of polysaccharide containing 3-O-methyl galactose from fruiting bodies of Pleurotus citrinopileatus.

    Science.gov (United States)

    He, Pengfei; Zhang, Anqiang; Zhou, Saijing; Zhang, Fuming; Linhardt, Robert J; Sun, Peilong

    2016-11-03

    A water-soluble polysaccharide containing 3-O-methyl galactose (PCP60W) was isolated from fruiting bodies of Pleurotus citrinopileatus and purified by anion-exchange and gel column chromatography. This polysaccharide has an average molecular weight of 2.74 × 10 4  Da and its structure was elucidated using monosaccharide composition and methylation analysis combined with one- and two-dimensional (COSY, TOCSY, NOESY, HMQC and HMBC) NMR spectroscopy. PCP60W was shown to be a linear partially 3-O-methylated α-galactopyranan comprised of 6-linked galactose, 6-linked 3-O-methyl galactose and 4-linked glucose in a ratio of 3.0:1.0:0.6. This work provides additional evidence for the view that 3-O-methyl galactose is common to the genus Pleurotus. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Structure elucidation and immunomodulatory activity of a beta glucan from the fruiting bodies of Ganoderma sinense.

    Directory of Open Access Journals (Sweden)

    Xiao-Qiang Han

    Full Text Available A polysaccharide named GSP-2 with a molecular size of 32 kDa was isolated from the fruiting bodies of Ganoderma sinense. Its structure was well elucidated, by a combined utilization of chemical and spectroscopic techniques, to be a β-glucan with a backbone of (1→4- and (1→6-Glcp, bearing terminal- and (1→3-Glcp side-chains at O-3 position of (1→6-Glcp. Immunological assay exhibited that GSP-2 significantly induced the proliferation of BALB/c mice splenocytes with target on only B cells, and enhanced the production of several cytokines in human peripheral blood mononuclear cells and derived dendritic cells. Besides, the fluorescent labeled GSP-2 was phagocytosed by the RAW 264.7 cells and induced the nitric oxide secretion from the cells.

  14. Structure-based elucidation of the regulatory mechanism for aminopeptidase activity.

    Science.gov (United States)

    Ta, Hai Minh; Bae, Sangsu; Han, Seungsu; Song, Jihyuck; Ahn, Tae Kyu; Hohng, Sungchul; Lee, Sangho; Kim, Kyeong Kyu

    2013-09-01

    The specificity of proteases for the residues in and length of substrates is key to understanding their regulatory mechanism, but little is known about length selectivity. Crystal structure analyses of the bacterial aminopeptidase PepS, combined with functional and single-molecule FRET assays, have elucidated a molecular basis for length selectivity. PepS exists in open and closed conformations. Substrates can access the binding hole in the open conformation, but catalytic competency is only achieved in the closed conformation by formation of the S1 binding pocket and proximal movement of Glu343, a general base, to the cleavage site. Hence, peptides longer than the depth of the binding hole block the transition from the open to the closed conformation, and thus length selection is a prerequisite for catalytic activation. A triple-sieve interlock mechanism is proposed featuring the coupling of length selectivity with residue specificity and active-site positioning.

  15. Structure elucidation of metabolite x17299 by interpretation of mass spectrometric data.

    Science.gov (United States)

    Zhang, Qibo; Ford, Lisa A; Evans, Anne M; Toal, Douglas R

    2017-01-01

    A major bottleneck in metabolomic studies is metabolite identification from accurate mass spectrometric data. Metabolite x17299 was identified in plasma as an unknown in a metabolomic study using a compound-centric approach where the associated ion features of the compound were used to determine the true molecular mass. The aim of this work is to elucidate the chemical structure of x17299, a new compound by de novo interpretation of mass spectrometric data. An Orbitrap Elite mass spectrometer was used for acquisition of mass spectra up to MS 4 at high resolution. Synthetic standards of N,N,N -trimethyl-l-alanyl-l-proline betaine (l,l-TMAP), a diastereomer, and an enantiomer were chemically prepared. The planar structure of x17299 was successfully proposed by de novo mechanistic interpretation of mass spectrometric data without any laborious purification and nuclear magnetic resonance spectroscopic analysis. The proposed structure was verified by deuterium exchanged mass spectrometric analysis and confirmed by comparison to a synthetic standard. Relative configuration of x17299 was determined by direct chromatographic comparison to a pair of synthetic diastereomers. Absolute configuration was assigned after derivatization of x17299 with a chiral auxiliary group followed by its chromatographic comparison to a pair of synthetic standards. The chemical structure of metabolite x17299 was determined to be l,l-TMAP.

  16. Structure elucidation and chromatographic identification of anthraquinone components of cochineal (Dactylopius coccus) detected in historical objects.

    Science.gov (United States)

    Stathopoulou, Konstantina; Valianou, Lemonia; Skaltsounis, Alexios-Leandros; Karapanagiotis, Ioannis; Magiatis, Prokopios

    2013-12-04

    Cochineal is one of the most well known organic red dyes. Dactylopius coccus Costa (Dactylopiidae) is a scale insect that is used as the source of the dye known as Mexican cochineal. Although cochineal is today a natural food colorant (E120) and although it has been used in art objects (textiles and paintings) for centuries, its exact chemical consistency is not well clarified except for carminic acid which is the major component and kermesic and flavokermesic acids. Several minor components (typically less than 5% of the colouring material) remained unknown or partially studied, although their presence has been reported in numerous analytical works related to art objects. Chemical investigation of the methanol extract of the dried insects, after subsequent HPLC chromatographic separations, led to the isolation and structure elucidation of six new anthraquinones, along with the known compounds carminic acid, kermesic acid and flavokermesic acid. The new compounds formerly described as DCII and DCIII, were found to be the 2-C-glucoside of flavokermesic acid and 4-aminocarminic acid, respectively, while DCIV and DCVII were found to be the α/β C-glucofuranosides of kermesic acid, and were studied as a mixture due to equilibrium. In addition, 3-O-glucoside of flavokermesic acid (DCOFK), and 3,4-dideoxycarminic acid (DDCA) were identified. The structures of the new compounds were elucidated on the basis of their NMR and MS data. Finally, the new compounds were detected in silk dyed with cochineal, lake pigment and, furthermore, in historical objects of the cultural heritage (icon and textile) using LC-DAD and LC-MS. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Methylbenzene-Containing Polyketides from a Streptomyces that Spontaneously Acquired Rifampicin Resistance: Structural Elucidation and Biosynthesis.

    Science.gov (United States)

    Thong, Wei Li; Shin-ya, Kazuo; Nishiyama, Makoto; Kuzuyama, Tomohisa

    2016-04-22

    Conventional screening for novel bioactive compounds in actinomycetes often results in the rediscovery of known compounds. In contrast, recent genome sequencing revealed that most of the predicted gene clusters for secondary metabolisms are not expressed under standard cultivation conditions. To explore the potential metabolites produced by these gene clusters, we implemented a cryptic gene activation strategy by screening mutants that acquire resistance to rifampicin. The induction of rifampicin resistance in 11 actinomycete strains generated 164 rifampicin-resistant mutants (rif mutants). The comparison of the metabolic profiles between the rif mutants and their wild-type strains indicated that one mutant (TW-R50-13) overproduced an unidentified metabolite (1). During the isolation and structural elucidation of metabolite 1, an additional metabolite was found; both are unprecedented compounds featuring a C5N unit and a methylbenzene moiety. Of these partial structures, the biosynthesis of the latter has not been reported. A feeding experiment using (13)C-labeled precursors demonstrated that the methylbenzene moiety is most likely synthesized by the action of polyketide synthase. The gene deletion experiments revealed that the genes for the methylbenzene moiety are located at a different locus than the genes for the C5N unit.

  18. Purification, structural elucidation, and anti-inflammatory activity of xylosyl galactofucan from Armillaria mellea.

    Science.gov (United States)

    Chang, Chia-Chuan; Cheng, Jing-Jy; Lee, I-Jung; Lu, Mei-Kuang

    2018-02-13

    A xylosyl 1,3-galactofucan (AMPS-III) was isolated and identified as a novel anti-inflammatory agent from an edible fungus, Armillaria mellea. The characteristics chemical structure of AMPS-III including the linkages of compositional monosaccharides and structure of the repeat unit were depicted and elucidated by proton, carbon and two-dimensional nuclear magnetic resonance techniques. AMPS-III was chemically proposed to have a partial 4-O-xylosylated 1,3-linked α-d-galactosyl-interlaced α-l-fucan composed of a pentadecasaccharide repeat unit with a molecular mass approximately 13 kDa. AMPS-III significantly suppressed the release of tumor necrosis factor-α (TNF-α) and cytokine monocyte chemotactic protein-1 (MCP-1) in RAW264.7 macrophages and EAhy926 following LPS and TNF-α induction. The results provide helpful evidences for application of AMPS-III as anti-inflammatory food supplements. Copyright © 2018. Published by Elsevier B.V.

  19. Synergic application of spectroscopic and theoretical methods to the chlorogenic acid structure elucidation

    Science.gov (United States)

    Marković, Svetlana; Tošović, Jelena; Dimitrić Marković, Jasmina M.

    2016-07-01

    Although chlorogenic acid (5-O-caffeoylquinic acid, 5CQA) is a dietary polyphenol known for its pharmacological and nutritional properties, its structural features have not been completely elucidated. This is the first study whose aim is to contribute to clarification of the 5CQA structure by comparing the experimental and simulated IR, Raman, 1H NMR, 13C NMR, and UV spectra. For this purpose, a comprehensive conformational analysis of 5CQA was performed to reveal its most stable conformations in the gas-state and solution (DMSO and methanol). The lowest-energy conformers were used to predict the spectra at two levels of theory: B3LYP-D3/and M06-2X/6-311+G(d,p) in combination with the CPCM solvation model. Both methods provide very good agreement between all experimental and simulated spectra, thus indicating correct arrangement of the atoms in the 5CQA molecule. The quinic moiety is characterized with directed hydrogen bonds, where the carboxylic hydrogen is not oriented towards the carbonyl oxygen of the carboxylic group, but towards the oxygen of the proximate hydroxyl group. In the gas-state the lowest-energy conformers are characterized with the O4sbnd H4 ⋯ O9‧ hydrogen bond, whereas in the solvated state the structures with the O4sbnd H4 ⋯ O10‧ hydrogen bond prevail. Knowing the fine structural details, i.e. the proper conformation of 5CQA, provides a solid base for all further investigations related to this compound.

  20. Structural elucidation of olive pomace fed sea bass (Dicentrarchus labrax) polar lipids with cardioprotective activities.

    Science.gov (United States)

    Nasopoulou, Constantina; Smith, Terry; Detopoulou, Maria; Tsikrika, Constantina; Papaharisis, Leonidas; Barkas, Dimitris; Zabetakis, Ioannis

    2014-02-15

    The purpose of this study was to structurally characterise the polar lipids of sea bass (Dicentrarchus labrax), fed with an experimental diet containing olive pomace (OP), that exhibit cardioprotective activities. OP has been added to conventional fish oil (FO) feed at 4% and this was the OP diet, having been supplemented as finishing diet to fish. Sea bass was aquacultured using either FO or OP diet. At the end of the dietary experiment, lipids in both samples of fish muscle were quantified and HPLC fractionated. The in vitro cardioprotective properties of the polar lipid fractions, using washed rabbit's platelets, have been assessed and the two most biologically active fractions were further analysed by mass spectrometry. The gas-chromatrograpy-mass spectrometric data shows that these two fractions contain low levels of myristic (14:0), oleic (18:1 cis ω-9) and linoleic acids (18:2 ω-6), but high levels of palmitic (16:0) and stearic acids (18:0) as well as eicosadienoic acid (20:2 ω-6). The first fraction (MS1) also contained significant levels of arachidonic acid (20:4 ω-6) and the omega-3 fatty acids: eicosapentaenoic acid (22:5) and docosahexaenoic acid (22:6). Electrospray-mass spectrometry elucidated that the lipid composition of the two fractions contained various diacyl-glycerophospholipids species, where the majority of them have either 18:0 or 18:1 fatty acids in the sn-1 position and either 22:6 or 20:2 fatty acids in the sn-2 position for MS1 and MS2, respectively. Our research focuses on the structure/function relationship of fish muscle polar lipids and cardiovascular diseases and structural data are given for polar lipid HPLC fractions with strong cardioprotective properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Methods for the comprehensive structural elucidation of constitution and stereochemistry of lipopeptides.

    Science.gov (United States)

    Gerhardt, Heike; Sievers-Engler, Adrian; Jahanshah, Ghazaleh; Pataj, Zoltán; Ianni, Federica; Gross, Harald; Lindner, Wolfgang; Lämmerhofer, Michael

    2016-01-08

    A panel of methods of general suitability for complete structural elucidation of the stereochemistry of cyclopeptides, depsipeptides and lipopeptides is presented and described in detail. The suitability of the proposed methods was exemplified on the lipopeptide poaeamide from Pseudomonas poae. Amino acid configurations have been assigned by direct LC enantiomer separation with Chiralpak ZWIX(+) and were confirmed by GC enantiomer separation on Chirasil L-Val. 3-Hydroxydecanoic acid absolute configuration was analyzed on Chiralpak ZWIX(+) and confirmed by injection on ZWIX(-) which showed opposite elution order. Plenty of d-amino acids have been found in this lipopeptide. It contained in total 5 Leu residues of which one had d-configuration. The position of the d-Leu in the peptide sequence was determined by pepsin and chemical digestions in combination with isolation of diagnostic peptide-fragments and subsequent identification of absolute configurations of the Leu residues. This allowed pinpointing the position of the d-amino acid. The complementarity of the peptide retention profiles on Chiralpak ZWIX column as compared to both RPLC and HILIC suggests its great utility as an alternative peptide separation tool. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Elucidation of structural and functional properties of albumin bound to gold nanoparticles.

    Science.gov (United States)

    Mariam, Jessy; Sivakami, S; Dongre, P M

    2017-02-01

    Nanoparticle-albumin complexes are being designed for targeted drug delivery and imaging. However, the changes in the functional properties of albumin due to adsorption on nanoparticles remain elusive. Thus, the objective of this work was to elucidate the structural and functional properties of human and bovine serum albumin bound to negatively charged gold nanoparticles (GNPs). Fluorescence data demonstrated static quenching of albumin by GNP with the quenching of buried as well as surface tryptophan in BSA. The binding process was enthalpy and entropy-driven in HSA and BSA, respectively. At lower concentrations of GNP there was a higher affinity for tryptophan, whereas at higher concentrations both tryptophan and tyrosine participated in the interaction. Synchronous fluorescence spectra revealed that the microenvironment of tryptophan in HSA turned more hydrophilic upon exposure to GNP. The α-helical content of albumin was unaltered by GNP. Approximately 37 and 23% reduction in specific activity of HSA and BSA was observed due to GNP binding. In presence of warfarin and ibuprofen the binding constants of albumin-GNP complexes were altered. A very interesting observation not reported so far is the retained antioxidant activity of albumin in presence of GNP i.e. we believe that GNPs did not bind to the free sulfhydryl groups of albumin. However enhanced levels of copper binding were observed. We have also highlighted the differential response in albumin due to gold and silver nanoparticles which could be attributed to differences in the charge of the nanoparticle.

  3. Structural elucidation and immunological activity of a polysaccharide from the fruiting body of Armillaria mellea.

    Science.gov (United States)

    Sun, Yongxu; Liang, Haitao; Zhang, Xiantao; Tong, Haibin; Liu, Jicheng

    2009-03-01

    The water-soluble polysaccharide (AMP), with a molecular mass of 7.8x10(3)Da as determined by high-performance size-exclusion chromatography (HPSEC), was obtained from the fruiting body of Armillaria mellea. Methylation, Smith degradation, acetolysis, (1)H and (13)C NMR spectroscopy and acid hydrolysis studies were conducted to elucidate its structure. The results indicated that AMP consisted of a backbone composed of (1-->6)-linked-alpha-D-glucopyranosyl, (1-->2,6)-linked-alpha-D-glucopyranosyl and (1-->6)-linked-alpha-D-galactopyranosyl residues in the ratio of 3:1:1, and terminated with one single terminal (1-->)-beta-D-glucopyranosyl at the O-2 position of (1-->2,6)-linked-alpha-D-glucopyranosyl, on average, along the main chain. Preliminary tests in vitro showed that AMP has stimulating effects on murine lymphocyte proliferation induced by concanavalin A or lipopolysaccharide in a dose-dependent manner. It is a possible potential immunopotentiating agent for use in health-care food or medicine.

  4. Elucidation of structural isomers from the homogeneous rhodium-catalyzed isomerization of vegetable oils.

    Science.gov (United States)

    Andjelkovic, Dejan D; Min, Byungrok; Ahn, Dong; Larock, Richard C

    2006-12-13

    The structural isomers formed by the homogeneous rhodium-catalyzed isomerization of several vegetable oils have been elucidated. A detailed study of the isomerization of the model compound methyl linoleate has been performed to correlate the distribution of conjugated isomers, the reaction kinetics, and the mechanism of the reaction. It has been shown that [RhCl(C8H8)2]2 is a highly efficient and selective isomerization catalyst for the production of highly conjugated vegetable oils with a high conjugated linoleic acid (CLA) content, which is highly desirable in the food industry. The combined fraction of the two major CLA isomers [(9Z,11E)-CLA and (10E,12Z)-CLA] in the overall CLA mixture is in the range from 76.2% to 93.4%. The high efficiency and selectivity of this isomerization method along with the straightforward purification process render this approach highly promising for the preparation of conjugated oils and CLA. Proposed improvements in catalyst recovery and reusability will only make this method more appealing to the food, paint, coating, and polymer industries in the future.

  5. Structural elucidation of the metabolites of lapachol in rats by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Bai, Lu; Han, Ying; Yao, Jinfeng; Li, Xiaorong; Li, Yuhang; Xu, Pinxiang; Xue, Ming

    2014-01-01

    Lapachol is a natural naphthoquinone compound derived from Bignoniaceae (Tabebuia sp.) that possesses a range of significant biological activities. Nine phase I and four phase II metabolites of lapachol in rat bile were firstly elucidated and identified using a sensitive LC-ESI-MS(n) method. The molecular structures of the metabolites have been presented on the basis of the characteristics of their precursor and product ions, as well as their fragmentation mechanisms and chromatographic retention times. The results indicated that the phase I metabolites were predominantly biotransformed by the hydroxylation, semiquinone hydrogenation at the oxygen position or a side chain rearrangement. The phase II metabolites were identified as the glucuronidated conjugates which showed a characteristic neutral loss of 176Da. Based on the results of this research, we have proposed the metabolic pathways for lapachol in rats. This work has provided novel information for the in vivo lapachol metabolism which could be used to develop a novel drug candidate, as well as a better understanding of the safety and efficacy of the drug. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Production and structure elucidation of di- and oligosaccharide lipids (biosurfactants) from Tsukamurella sp. nov.

    Science.gov (United States)

    Vollbrecht, E; Heckmann, R; Wray, V; Nimtz, M; Lang, S

    1998-11-01

    The bacterium Tsukamurella sp. nov., isolated from soil, was found to produce novel glycolipids when grown on sunflower oil as the sole carbon source. The glycolipids were isolated by chromatography on silica columns and their structures elucidated using a combination of multidimensional NMR and MS techniques. The three main components are 2,3-di-O-acyl-alpha-D-glucopyranosyl-(1-1)-alpha-D-glucopyranose, 2,3-di-O-acyl-beta-D-glucopyranosyl-(1-2)-4,6-di-O-acyl-alpha-D- glucopyranosyl-(1-1)-alpha-D-glucopyranose and 2,3-di-O-acyl-beta-D-glucopyranosyl-(1-2)-beta-D-galactopyranosyl- (1-6)-4,6-di-O-acyl-alpha-D-glucopyranosyl-(1-1)-alpha-D- glucopyranosyl which are linked to fatty acids varying in chain length from C4 to C18. The glycolipids are mainly extracellular but are also found attached to the cell walls. During the cultivation the composition of the glycolipids changed from disaccharide- to tri- and tetrasaccharide lipids. The glycolipids show good surface-active behaviour and have antimicrobial properties.

  7. Structural elucidation of major selective androgen receptor modulator (SARM) metabolites for doping control.

    Science.gov (United States)

    Garg, Neeraj; Hansson, Annelie; Knych, Heather K; Stanley, Scott D; Thevis, Mario; Bondesson, Ulf; Hedeland, Mikael; Globisch, Daniel

    2018-01-31

    Selective androgen receptor modulators (SARMs) are a class of androgen receptor drugs, which have a high potential to be performance enhancers in human and animal sports. Arylpropionamides are one of the major SARM classes and get rapidly metabolized significantly complicating simple detection of misconduct in blood or urine sample analysis. Specific drug-derived metabolites are required as references due to a short half-life of the parent compound but are generally lacking. The difficulty in metabolism studies is the determination of the correct regio and stereoselectivity during metabolic conversion processes. In this study, we have elucidated and verified the chemical structure of two major equine arylpropionamide-based SARM metabolites using a combination of chemical synthesis and liquid chromatography-mass spectrometry (LC-MS) analysis. These synthesized SARM-derived metabolites can readily be utilized as reference standards for routine mass spectrometry-based doping control analysis of at least three commonly used performance-enhancing drugs to unambigously identify misconduct.

  8. Isolation and structure elucidation of phenolic antioxidants from Tamarind (Tamarindus indica L.) seeds and pericarp.

    Science.gov (United States)

    Sudjaroen, Y; Haubner, R; Würtele, G; Hull, W E; Erben, G; Spiegelhalder, B; Changbumrung, S; Bartsch, H; Owen, R W

    2005-11-01

    Although it is already known that Tamarind (Tamarindus indica L.) seeds contain phenolic substances, the individual components of the seeds have not been fully identified and quantitated, and in the case of Tamarind pericarp not reported. Therefore, major polyphenolic compounds were extracted using organic solvents and the metabolites were isolated by semi-preparative high performance liquid chromatography. Their structures were elucidated by liquid chromatography-electrospray-ionisation-mass spectrometry (LC-ESI-MS), nano-electrospray-ionisation mass spectrometry (ESI-MS), and where possible by gas chromatography-mass spectrometry (GC-MS) and 1H and 13C NMR. Quantitative analysis of polyphenolic compounds in Tamarind seeds and pericarp was conducted by analytical high performance liquid chromatography (HPLC), calculated against standard curves of authentic compounds. The yields of total phenolic compounds after Soxhlet extraction with methanol were 6.54 and 2.82 g/kg (dry weight) in the seeds and pericarp respectively. The profile (%) of polyphenolics in Tamarind pericarp was dominated by proanthcyanidins (73.4) in various forms (+)-catechin (2.0), procyanidin B2 (8.2), (-)-epicatechin (9.4), procyanidin trimer (11.3), procyanidin tetramer (22.2), procyanidin pentamer (11.6), procyanidin hexamer (12.8) along with taxifolin (7.4), apigenin (2.0), eriodictyol (6.9), luteolin (5.0) and naringenin (1.4) of total phenols, respectively. The content of Tamarind seeds comprised only procyanidins, represented (%) mainly by oligomeric procyanidin tetramer (30.2), procyanidin hexamer (23.8), procyanidin trimer (18.1), procyanidin pentamer (17.6) with lower amounts of procyanidin B2 (5.5) and (-)-epicatechin (4.8). Extraction of Tamarind pericarp and seeds using acetone:methanol:acetic acid gave only procyanidin oligomers, but in much higher yield and variety. The antioxidant capacities of the Soxhlet methanolic extracts were determined, and indicates that Tamarind may be an

  9. DFT and EXAFS, mutually enhancing tools for structure elucidation of Tc complexes

    International Nuclear Information System (INIS)

    Breynaert, E.; Bruggeman, C.; Maes, A.

    2005-01-01

    Full text of publication follows: The redox-sensitive fission product technetium-99 (Tc) is of great interest in nuclear waste disposal studies because of its potential for contaminating the geosphere due to its very long half-life (2.13 x 10 5 year) and high mobility under oxidising conditions, where technetium forms pertechnetate (TcO 4 - ). Under suitable reducing conditions, e.g. in the presence of an iron(II) containing solid phase which can act as an electron donor, the solubility can be limited by the reduction of pertechnetate followed by the formation of a surface precipitate [1]. However, by association with mobile humic substances (HS) or other associating/complexing species, the solubility of reduced Tc species may be drastically enhanced [2]. The elucidation of the identity and geometrical structure of the species causing this enhanced solubility often remains a difficult issue. Extended X-Ray Absorption Fluorescence Spectroscopy/ X-Ray Absorption Near Edge Spectroscopy (EXAFS/XANES) analysis can be very helpful to determine the molecular surroundings of reduced Tc organic complexes of Tc(IV) colloid-HS-associations. The interpretation of the EXAFS spectra is however not a straightforward process due to the possibly strong influence of multiple scattering paths on the spectra. Contrary to single scattering analysis which can be easily performed on the experimental EXAFS spectra, multiple scattering analysis can only be done, based on good approximations of the possible geometrical structures of the species under consideration. It has been shown that the Density Functional Theory (DFT) can be used to perform geometry optimizations of technetium species and therefore can be utilized to predict the structure of technetium complexes [3]. The success and computational effort needed for such structure predictions are however highly dependant on the quality of the initial structure from which the geometry optimization is started. Single scattering analysis of

  10. Molecular Insights into the Transmembrane Domain of the Thyrotropin Receptor.

    Directory of Open Access Journals (Sweden)

    Vanessa Chantreau

    Full Text Available The thyrotropin receptor (TSHR is a G protein-coupled receptor (GPCR that is member of the leucine-rich repeat subfamily (LGR. In the absence of crystal structure, the success of rational design of ligands targeting the receptor internal cavity depends on the quality of the TSHR models built. In this subfamily, transmembrane helices (TM 2 and 5 are characterized by the absence of proline compared to most receptors, raising the question of the structural conformation of these helices. To gain insight into the structural properties of these helices, we carried out bioinformatics and experimental studies. Evolutionary analysis of the LGR family revealed a deletion in TM5 but provided no information on TM2. Wild type residues at positions 2.58, 2.59 or 2.60 in TM2 and/or at position 5.50 in TM5 were substituted to proline. Depending on the position of the proline substitution, different effects were observed on membrane expression, glycosylation, constitutive cAMP activity and responses to thyrotropin. Only proline substitution at position 2.59 maintained complex glycosylation and high membrane expression, supporting occurrence of a bulged TM2. The TSHR transmembrane domain was modeled by homology with the orexin 2 receptor, using a protocol that forced the deletion of one residue in the TM5 bulge of the template. The stability of the model was assessed by molecular dynamics simulations. TM5 straightened during the equilibration phase and was stable for the remainder of the simulations. Our data support a structural model of the TSHR transmembrane domain with a bulged TM2 and a straight TM5 that is specific of glycoprotein hormone receptors.

  11. Nature's Cholesterol-Lowering Drug: Isolation and Structure Elucidation of Lovastatin from Red Yeast Rice-Containing Dietary Supplements

    Science.gov (United States)

    Nazri, Maisarah Mohd; Samat, Farah D.; Kavanagh, Pierce V.; Walsh, John J.

    2012-01-01

    Red yeast rice, produced by fermenting the fungus, "Monascus purpureus", on rice ("Oryza sativa" L. gramineae), is commonly used as a dietary supplement. It contains lovastatin, a member of the statin family of compounds, and is licensed for use as a cholesterol-lowering agent. This experiment involves the isolation and structure elucidation of…

  12. Production of specific-structured lipids by enzymatic interesterification: elucidation of acyl migration by response surface design

    DEFF Research Database (Denmark)

    Xu, Xuebing; Skands, Anja; Høy, Carl-Erik

    1998-01-01

    Production of specific-structured lipids (SSL) by lipase-catalyzed interesterification has been attracting more and more attention recently. However, it was found that acyl migration occurs during the reaction and causes the production of by-products. In this paper, the elucidation of acyl migrat...

  13. pH-Controlled Oxidation of an Aromatic Ketone: Structural Elucidation of the Products of Two Green Chemical Reactions

    Science.gov (United States)

    Ballard, C. Eric

    2010-01-01

    A laboratory experiment emphasizing the structural elucidation of organic compounds has been developed as a discovery exercise. The "unknown" compounds are the products of the pH-controlled oxidation of 4'-methoxyacetophenone with bleach. The chemoselectivity of this reaction is highly dependent on the pH of the reaction media: under basic…

  14. Isolation and structure elucidation of an interaction product of aminotadalafil found in an illegal health food product.

    Science.gov (United States)

    Häberli, Adrian; Girard, Philippe; Low, Min-Yong; Ge, Xiaowei

    2010-09-21

    An interaction product of aminotadalafil was isolated from an illegal health food product. The structure of the interaction product was elucidated by means of IR, NMR, and mass spectroscopy. The hitherto unknown compound was characterized as condensation product of aminotadalafil and hydroxymethylfuraldehyde and is probably the result of a drug-excipient incompatibility. Copyright 2010. Published by Elsevier B.V.

  15. Flavonoid glycosides from Olax mannii: Structure elucidation and effect on the nuclear factor kappa B pathway.

    Science.gov (United States)

    Okoye, Festus B C; Sawadogo, Wamtinga Richard; Sendker, Jandirk; Aly, Amal H; Quandt, Bettina; Wray, Victor; Hensel, Andreas; Esimone, Charles O; Debbab, Abdessamad; Diederich, Marc; Proksch, Peter

    2015-12-24

    Olax mannii Oliv. (Olacaceae) is among the many medicinal plants used in Nigeria for the ethnomedicinal management of both cancer and inflammation. Such plants represent potential sources of innovative therapeutic agents for the treatment of cancer and other malignant disorders. While the majority of medicinal plants exert their anticancer effects by direct cytotoxicity on tumor cells, it is important that other mechanisms through which these plants can exhibit anticancer effects are investigated. Preliminary studies indicated that Olax mannii leaves are rich sources of novel flavonoid glycosides. The detailed chemistry as well the mechanisms through which these flavonoid constituents may exert their cancer chemo-preventive and therapeutic effects are, however, not yet investigated. The aim of this study is to carry out a detailed chemical investigation of Olax mannii leaves and the effects of the isolated constituents on the nuclear factor kappa B (NF-κB) pathway. A methanol leaf extract was subjected to various chromatographic separations to achieve isolation of flavonoid glycosides and the structures of the isolated compounds were elucidated by a combination of 1D and 2D NMR and high resolution mass spectrometry. Biological activities were assessed by measurement of cellular viability and proliferation using quantitative IncuCyte videomicroscopy, trypan blue staining and by quantification of the number of metabolically active K562 cells based on quantitation of ATP. The effect of the compounds on the inhibition of the NF-κB pathway as well as toxicity towards peripheral blood mononuclear cells to evaluate differential toxicity was also assayed. Chemical investigation of the methanol leaf extract of the plant material led to the isolation of three new flavonoid triglycosides, kaempferol 3-O-[α-D-apiofuranosyl-(1 → 2)-α-L-arabinofuranoside]-7-O-α-L-rhamnopyranoside (1), kaempferol 3-O-[β-D-glucopyranosyl-(1 → 2)-α-L-arabinofuranoside]-7-O

  16. Isolation and structural elucidation of secondary metabolites from plants of the Rutaceae family, Rubiaceae, Euphorbiaceae and Salicaceae

    International Nuclear Information System (INIS)

    Calderon Castro, Carlos

    2014-01-01

    A phytochemical study was conducted of the Zuelania guidonia plants (Salicaceae), croton ovalifolius (Euphorbiaceae) erythrochiton gymnanthus (Rutaceae) and Faramea occidentalis (Rubiaceae). Purification of the compounds was carried out using chromatographic techniques while structural elucidation was performed by experiments using nuclear magnetic resonance (NMR) and mass spectrometry (MS). Of Z. guidonia has been possible the purification and structural elucidation of 22 compounds (Z1-Z22), two labdane type diterpenes and 20 clerodane-type diterpenes. The clerodanes have presented 16 innovative structure, highlighting the presence of a group of 3,6-dihydro -1.2-dioxin and xylose group in some of them. In addition, 11 of the clerodanes were evaluated with cytotoxicity assays in three cancer cell lines CCRF-CEM (acute lymphoblastic leukemia), CEM-ADR5000 (acute lymphoblastic leukemia resistant to doxorubicin) MIA-Paca-2 (metastatic pancreas) and a line of healthy cells PBMC (peripheral blood mononuclear cells). The Z4, Z6 and Z15 compounds stood out as the most cytotoxic, particularly against CCRF-CEM cells with IC 50 values between 1.6 and 2.5 μM. Seven compounds identified as glutarimide alkaloids (C1-C7) were isolated and elucidated, five of which have presented a novel structure from C. ovalifolius. Three compounds (E1-E3) that are triterpenes derivatives of known structure sitosterol, were isolated and elucidated from E. gymnanthus plant. From F. occidentalis was obtained the structure of a pure compound (F1], which is a flavonoid of known structure. (author) [es

  17. Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis

    Directory of Open Access Journals (Sweden)

    Zheng Yang

    2016-02-01

    Full Text Available Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3, were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473, one of important cancer drugs target.

  18. The fundamentals behind solving for unknown molecular structures using computer-assisted structure elucidation: a free software package at the undergraduate and graduate levels.

    Science.gov (United States)

    Moser, Arvin; Pautler, Brent G

    2016-05-15

    The successful elucidation of an unknown compound's molecular structure often requires an analyst with profound knowledge and experience of advanced spectroscopic techniques, such as Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry. The implementation of Computer-Assisted Structure Elucidation (CASE) software in solving for unknown structures, such as isolated natural products and/or reaction impurities, can serve both as elucidation and teaching tools. As such, the introduction of CASE software with 112 exercises to train students in conjunction with the traditional pen and paper approach will strengthen their overall understanding of solving unknowns and explore of various structural end points to determine the validity of the results quickly. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Timing of Levothyroxine Administration Affects Serum Thyrotropin Concentration

    OpenAIRE

    Bach-Huynh, Thien-Giang; Nayak, Bindu; Loh, Jennifer; Soldin, Steven; Jonklaas, Jacqueline

    2009-01-01

    Context: Patients treated with levothyroxine typically ingest it in a fasting state to prevent food impairing its absorption. The serum thyrotropin concentration is the therapeutic index of levothyroxine action.

  20. Structure of E. coli 16S RNA elucidated by psoralen crosslinking

    International Nuclear Information System (INIS)

    Thompson, J.F.; Hearst, J.E.

    1983-01-01

    E. coli 16S RNA in solution was photoreacted with hydroxymethyltrimethylpsoralen and long wave ultraviolet light. Positions of crosslinks were determined to high resolution by partially digesting the RNA with T 1 RNase, separating the crosslinked fragments by two-dimensional gel electrophoresis, reversing the crosslink, and sequencing the separated fragments. This method yielded the locations of crosslinks to +/-15 nucleotides. Even finer placement has been made on the basis of our knowledge of psoralen reactivity. Thirteen unique crosslinks were mapped. Seven crosslinks confirmed regions of secondary structure which had been predicted in published phylogenetic models, three crosslinks discriminated between phylogenetic models, and three proved the existence of new structures. The new structures were all long-range interactions which appear to be in dynamic equilibrium with local secondary structure. Because this technique yields direct information about the secondary structure of large RNAs, it should prove invaluable in studying the structure of other RNAs of all sizes

  1. Expert systems for structure elucidation of organic molecules by spectral methods

    International Nuclear Information System (INIS)

    Elyashberg, Mikhail E

    1999-01-01

    The state-of-the-art of the investigations aimed at creating expert systems for establishing the structure of organic molecules from IR, 1 H and 13 C NMR spectra is analysed. Computer methods used for identification of molecular fragments, generation of their structure and spectra prediction are considered. Principles of the creation of modern expert systems and general strategy of solving structural problems are discussed. The bibliography includes 174 references.

  2. Using FT-IR Spectroscopy to Elucidate the Structures of Ablative Polymers

    Science.gov (United States)

    Fan, Wendy

    2011-01-01

    The composition and structure of an ablative polymer has a multifaceted influence on its thermal, mechanical and ablative properties. Understanding the molecular level information is critical to the optimization of material performance because it helps to establish correlations with the macroscopic properties of the material, the so-called structure-property relationship. Moreover, accurate information of molecular structures is also essential to predict the thermal decomposition pathways as well as to identify decomposition species that are fundamentally important to modeling work. In this presentation, I will describe the use of infrared transmission spectroscopy (FT-IR) as a convenient tool to aid the discovery and development of thermal protection system materials.

  3. Protein Structure Elucidation from NMR Data with the Program Xplor-NIH.

    Science.gov (United States)

    Bermejo, Guillermo A; Schwieters, Charles D

    2018-01-01

    Xplor-NIH is a popular software package for biomolecular structure determination from NMR (and other) experimental data. This chapter illustrates its use with the de novo structure determination of the B1 domain of streptococcal protein G (GB1), based on distances from nuclear Overhauser effects, torsion angles from scalar couplings, and bond-vector orientations from residual dipolar couplings. Including Xplor-NIH's latest developments, a complete structure calculation script is discussed in detail, and is intended to serve as a basis for other applications.

  4. The importance of asking "how and why?" in natural product structure elucidation.

    Science.gov (United States)

    Brown, Patrick D; Lawrence, Andrew L

    2017-10-18

    Covering: up to 2017This review highlights why careful consideration of the biosynthetic origin (the how) and the biological function (the why) of a natural product can be so useful during the determination of its structure. Recent examples of structural reassignments inspired by biosynthetic and functional insights will be presented. This review will demonstrate the importance of viewing the origin, structure and function of a natural product as intertwined threads of a single story, best viewed as a whole rather than as discrete topics.

  5. Expression, crystallization and structure elucidation of γ-terpinene synthase from Thymus vulgaris.

    Science.gov (United States)

    Rudolph, Kristin; Parthier, Christoph; Egerer-Sieber, Claudia; Geiger, Daniel; Muller, Yves A; Kreis, Wolfgang; Müller-Uri, Frieder

    2016-01-01

    The biosynthesis of γ-terpinene, a precursor of the phenolic isomers thymol and carvacrol found in the essential oil from Thymus sp., is attributed to the activitiy of γ-terpinene synthase (TPS). Purified γ-terpinene synthase from T. vulgaris (TvTPS), the Thymus species that is the most widely spread and of the greatest economical importance, is able to catalyze the enzymatic conversion of geranyl diphosphate (GPP) to γ-terpinene. The crystal structure of recombinantly expressed and purified TvTPS is reported at 1.65 Å resolution, confirming the dimeric structure of the enzyme. The putative active site of TvTPS is deduced from its pronounced structural similarity to enzymes from other species of the Lamiaceae family involved in terpenoid biosynthesis: to (+)-bornyl diphosphate synthase and 1,8-cineole synthase from Salvia sp. and to (4S)-limonene synthase from Mentha spicata.

  6. Structural elucidation of the polysaccharide moiety of a glycopeptide (GLPCW-II) from Ganoderma lucidum fruiting bodies.

    Science.gov (United States)

    Ye, LiBin; Zhang, JingSong; Ye, XiJun; Tang, QingJiu; Liu, YanFang; Gong, ChunYu; Du, XiuJui; Pan, YingJie

    2008-03-17

    A water-soluble glycopeptide (GLPCW-II) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE-Sepharose Fast-Flow and Sephacryl S-300 High Resolution Chromatography. The glycopeptide had a molecular weight of 1.2x10(4)Da (determined by HPLC), and consisted of approximately 90% carbohydrate and approximately 8% protein as determined using the phenol-sulfuric acid method and the BCA protein assay reagent kit, respectively. The polysaccharide moiety was composed mainly of D-Glc, L-Fuc, and D-Gal in the ratio of 1.00:1.09:4.09. To facilitate structure-activity studies, the structure of the GLPCW-II polysaccharide moiety was elucidated using 1H and 13C NMR spectroscopy including COSY, TOCSY, HMBC, HSQC, and ROESY, combined with GC-MS of methylated derivatives, and shown to consist of repeating units with the following structure: [Formula: see text].

  7. Enhanced measurement of residual chemical shift anisotropy for small molecule structure elucidation.

    Science.gov (United States)

    Liu, Yizhou; Cohen, Ryan D; Gustafson, Kirk R; Martin, Gary E; Williamson, R Thomas

    2018-03-05

    A method is introduced to measure residual chemical shift anisotropies conveniently and accurately in the mesophase of poly-γ-(benzyl-l-glutamate). The alignment amplitude is substantially enhanced over common methods which greatly benefits measurements particularly on sp 3 carbons. The approach offers significant improvements in data accuracy and utility for small molecule structure determination.

  8. Isolation and Structure Elucidation of a Novel Yellow Pigment from the Marine Bacterium Pseudoalteromonas tunicata

    Directory of Open Access Journals (Sweden)

    N. Kumar

    2005-10-01

    Full Text Available The marine environment is a major source for many novel natural compounds. A new yellow pigment has been isolated from the marine bacterium P. tunicata and identified as a new member of the tambjamine class of compounds. The structural identification was achieved by a combination of 1D and 2D-NMR spectroscopy and high resolution mass spectrometry data.

  9. Using Jigsaw-Style Spectroscopy Problem-Solving to Elucidate Molecular Structure through Online Cooperative Learning

    Science.gov (United States)

    Winschel, Grace A.; Everett, Renata K.; Coppola, Brian P.; Shultz, Ginger V.

    2015-01-01

    Cooperative learning was employed as an instructional approach to facilitate student development of spectroscopy problem solving skills. An interactive online environment was used as a framework to structure weekly discussions around spectroscopy problems outside of class. Weekly discussions consisted of modified jigsaw-style problem solving…

  10. Elucidating the influence of polymorph-dependent interfacial solvent structuring at chitin surfaces.

    Science.gov (United States)

    Brown, Aaron H; Walsh, Tiffany R

    2016-10-20

    Interfacial solvent structuring is thought to be influential in mediating the adsorption of biomolecules at aqueous materials interfaces. However, despite the enormous potential for exploitation of aqueous chitin interfaces in industrial, medical and drug-delivery applications, little is known at the molecular-level about such interfacial solvent structuring for chitin. Here we use molecular simulation to predict the structure of the [100] and [010] interfaces of α-chitin and β-chitin dihydrate in contact with liquid water and saline solution. We find the α-chitin [100] interface supports lateral high-density regions in the first water layer at the interface, which are also present, but not as pronounced, for β-chitin. The lateral structuring of interfacial ions at the saline/chitin interface is also more pronounced for α-chitin compared with β-chitin. Our findings provide a foundation for the systematic design of biomolecules with selective binding affinity for different chitin polymorphs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Structural annotation and elucidation of conjugated phenolic compounds in black, green, and white tea extracts

    NARCIS (Netherlands)

    Hooft, van der J.J.J.; Akermi, M.; Yelda Ünlü, F.; Mihaleva, V.; Gomez Roldan, V.; Bino, R.J.; Vos, de R.C.H.; Vervoort, J.J.M.

    2012-01-01

    Advanced analytical approaches consisting of both LC-LTQ-Orbitrap Fourier transformed (FT)-MS and LC-time-of-flight-(TOF)-MS coupled to solid-phase extraction (SPE) NMR were used to obtain more insight into the complex phenolic composition of tea. On the basis of the combined structural information

  12. Structural elucidation and NMR assignments of a new pyrrolizidine alkaloid from Crotalaria vitellina Ker Gawl.

    Science.gov (United States)

    Casimiro Bezerra, Denise Aline; Fechine Tavares, Josean; dos Santos, Paula Ferreira; Castello Branco, Marianna Vieira Sobral; de Fátima Agra, Maria; Subrinho, Fernanda Lima; Braz-Filho, Raimundo; da Silva, Marcelo Sobral

    2013-08-01

    A new pyrrolizidine alkaloid, named crotavitelin, was isolated from fruits of Crotalaria vitellina, Fabaceae (Papilionoideae). The structure was established by spectroscopic techniques such as one-dimensional and two-dimensional NMR, IR, and MS. Copyright © 2013 John Wiley & Sons, Ltd.

  13. Structural and Functional Elucidation of Yeast Lanosterol 14α-Demethylase in Complex with Agrochemical Antifungals.

    Directory of Open Access Journals (Sweden)

    Joel D A Tyndall

    Full Text Available Azole antifungals, known as demethylase inhibitors (DMIs, target sterol 14α-demethylase (CYP51 in the ergosterol biosynthetic pathway of fungal pathogens of both plants and humans. DMIs remain the treatment of choice in crop protection against a wide range of fungal phytopathogens that have the potential to reduce crop yields and threaten food security. We used a yeast membrane protein expression system to overexpress recombinant hexahistidine-tagged S. cerevisiae lanosterol 14α-demethylase and the Y140F or Y140H mutants of this enzyme as surrogates in order characterize interactions with DMIs. The whole-cell antifungal activity (MIC50 values of both the R- and S-enantiomers of tebuconazole, prothioconazole (PTZ, prothioconazole-desthio, and oxo-prothioconazole (oxo-PTZ as well as for fluquinconazole, prochloraz and a racemic mixture of difenoconazole were determined. In vitro binding studies with the affinity purified enzyme were used to show tight type II binding to the yeast enzyme for all compounds tested except PTZ and oxo-PTZ. High resolution X-ray crystal structures of ScErg11p6×His in complex with seven DMIs, including four enantiomers, reveal triazole-mediated coordination of all compounds and the specific orientation of compounds within the relatively hydrophobic binding site. Comparison with CYP51 structures from fungal pathogens including Candida albicans, Candida glabrata and Aspergillus fumigatus provides strong evidence for a highly conserved CYP51 structure including the drug binding site. The structures obtained using S. cerevisiae lanosterol 14α-demethylase in complex with these agrochemicals provide the basis for understanding the impact of mutations on azole susceptibility and a platform for the structure-directed design of the next-generation of DMIs.

  14. Structural and Functional Elucidation of Yeast Lanosterol 14α-Demethylase in Complex with Agrochemical Antifungals.

    Science.gov (United States)

    Tyndall, Joel D A; Sabherwal, Manya; Sagatova, Alia A; Keniya, Mikhail V; Negroni, Jacopo; Wilson, Rajni K; Woods, Matthew A; Tietjen, Klaus; Monk, Brian C

    2016-01-01

    Azole antifungals, known as demethylase inhibitors (DMIs), target sterol 14α-demethylase (CYP51) in the ergosterol biosynthetic pathway of fungal pathogens of both plants and humans. DMIs remain the treatment of choice in crop protection against a wide range of fungal phytopathogens that have the potential to reduce crop yields and threaten food security. We used a yeast membrane protein expression system to overexpress recombinant hexahistidine-tagged S. cerevisiae lanosterol 14α-demethylase and the Y140F or Y140H mutants of this enzyme as surrogates in order characterize interactions with DMIs. The whole-cell antifungal activity (MIC50 values) of both the R- and S-enantiomers of tebuconazole, prothioconazole (PTZ), prothioconazole-desthio, and oxo-prothioconazole (oxo-PTZ) as well as for fluquinconazole, prochloraz and a racemic mixture of difenoconazole were determined. In vitro binding studies with the affinity purified enzyme were used to show tight type II binding to the yeast enzyme for all compounds tested except PTZ and oxo-PTZ. High resolution X-ray crystal structures of ScErg11p6×His in complex with seven DMIs, including four enantiomers, reveal triazole-mediated coordination of all compounds and the specific orientation of compounds within the relatively hydrophobic binding site. Comparison with CYP51 structures from fungal pathogens including Candida albicans, Candida glabrata and Aspergillus fumigatus provides strong evidence for a highly conserved CYP51 structure including the drug binding site. The structures obtained using S. cerevisiae lanosterol 14α-demethylase in complex with these agrochemicals provide the basis for understanding the impact of mutations on azole susceptibility and a platform for the structure-directed design of the next-generation of DMIs.

  15. Structural and Functional Elucidation of Yeast Lanosterol 14α-Demethylase in Complex with Agrochemical Antifungals

    Science.gov (United States)

    Sagatova, Alia A.; Keniya, Mikhail V.; Negroni, Jacopo; Wilson, Rajni K.; Woods, Matthew A.; Monk, Brian C.

    2016-01-01

    Azole antifungals, known as demethylase inhibitors (DMIs), target sterol 14α-demethylase (CYP51) in the ergosterol biosynthetic pathway of fungal pathogens of both plants and humans. DMIs remain the treatment of choice in crop protection against a wide range of fungal phytopathogens that have the potential to reduce crop yields and threaten food security. We used a yeast membrane protein expression system to overexpress recombinant hexahistidine-tagged S. cerevisiae lanosterol 14α-demethylase and the Y140F or Y140H mutants of this enzyme as surrogates in order characterize interactions with DMIs. The whole-cell antifungal activity (MIC50 values) of both the R- and S-enantiomers of tebuconazole, prothioconazole (PTZ), prothioconazole-desthio, and oxo-prothioconazole (oxo-PTZ) as well as for fluquinconazole, prochloraz and a racemic mixture of difenoconazole were determined. In vitro binding studies with the affinity purified enzyme were used to show tight type II binding to the yeast enzyme for all compounds tested except PTZ and oxo-PTZ. High resolution X-ray crystal structures of ScErg11p6×His in complex with seven DMIs, including four enantiomers, reveal triazole-mediated coordination of all compounds and the specific orientation of compounds within the relatively hydrophobic binding site. Comparison with CYP51 structures from fungal pathogens including Candida albicans, Candida glabrata and Aspergillus fumigatus provides strong evidence for a highly conserved CYP51 structure including the drug binding site. The structures obtained using S. cerevisiae lanosterol 14α-demethylase in complex with these agrochemicals provide the basis for understanding the impact of mutations on azole susceptibility and a platform for the structure-directed design of the next-generation of DMIs. PMID:27907120

  16. Raman mapping in the elucidation of solid salt eutectic and near eutectic structures

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Kerridge, D. H.

    2002-01-01

    The distribution of the different components of solidified eutectic or near-eutectic salt mixtures (eutectics) was examined by use of Raman microscope mapping of the structures formed when these melts were slowly cooled. Seven binary and one ternary system were investigated. In most cases...... the component crystallized phases consisted of roughly rounded areas of about 0.5-5 mum across, the areas alternating in all directions across the sections. These three-dimensional structures may best be described by the terns 'conglomerate.' The size of these areas depended on the cooling rate...... and the composition. When unidirectional cooling was applied it was possible for the system (KCl-Na2SO4, 60:40 mol/mol) to observe lamellar arrangements of the component phases, in an arrangement closely similar to what is frequently found among metallic or ceramic eutectics. Each area, conglomerate or lamellar, did...

  17. Preparation of a Ammonia-Treated Lac Dye and Structure Elucidation of Its Main Component.

    Science.gov (United States)

    Nishizaki, Yuzo; Ishizuki, Kyoko; Akiyama, Hiroshi; Tada, Atsuko; Sugimoto, Naoki; Sato, Kyoko

    2016-01-01

    Lac dye and cochineal extract contain laccaic acids and carminic acid as the main pigments, respectively. Both laccaic acids and carminic acid are anthraquinone derivatives. 4-Aminocarminic acid (acid-stable carmine), an illegal colorant, has been detected in several processed foods. 4-Aminocarminic acid is obtained by heating cochineal extract (carminic acid) in ammonia solution. We attempted to prepare ammonia-treated lac dye and to identify the structures of the main pigment components. Ammonia-treated lac dye showed acid stability similar to that of 4-aminocarminic acid. The structures of the main pigments in ammonia-treated lac dye were analyzed using LC/MS. One of the main pigments was isolated and identified as 4-aminolaccaic acid C using various NMR techniques, including 2D-INADEQUATE. These results indicated that ammonia-treatment of lac dye results in the generation of 4-aminolaccaic acids.

  18. Structures of bovine glutamate dehydrogenase complexes elucidate the mechanism of purine regulation.

    Science.gov (United States)

    Smith, T J; Peterson, P E; Schmidt, T; Fang, J; Stanley, C A

    2001-03-23

    Glutamate dehydrogenase is found in all organisms and catalyses the oxidative deamination of l-glutamate to 2-oxoglutarate. However, only animal GDH utilizes both NAD(H) or NADP(H) with comparable efficacy and exhibits a complex pattern of allosteric inhibition by a wide variety of small molecules. The major allosteric inhibitors are GTP and NADH and the two main allosteric activators are ADP and NAD(+). The structures presented here have refined and modified the previous structural model of allosteric regulation inferred from the original boGDH.NADH.GLU.GTP complex. The boGDH.NAD(+).alpha-KG complex structure clearly demonstrates that the second coenzyme-binding site lies directly under the "pivot helix" of the NAD(+) binding domain. In this complex, phosphates are observed to occupy the inhibitory GTP site and may be responsible for the previously observed structural stabilization by polyanions. The boGDH.NADPH.GLU.GTP complex shows the location of the additional phosphate on the active site coenzyme molecule and the GTP molecule bound to the GTP inhibitory site. As expected, since NADPH does not bind well to the second coenzyme site, no evidence of a bound molecule is observed at the second coenzyme site under the pivot helix. Therefore, these results suggest that the inhibitory GTP site is as previously identified. However, ADP, NAD(+), and NADH all bind under the pivot helix, but a second GTP molecule does not. Kinetic analysis of a hyperinsulinism/hyperammonemia mutant strongly suggests that ATP can inhibit the reaction by binding to the GTP site. Finally, the fact that NADH, NAD(+), and ADP all bind to the same site requires a re-analysis of the previous models for NADH inhibition. Copyright 2001 Academic Press.

  19. Well-defined azazirconacyclopropane complexes supported on silica structurally determined by 2D NMR comparative elucidation

    KAUST Repository

    El Eter, Mohamad

    2013-01-01

    Grafting of Zr(NMe2)4 on mesoporous silica SBA-15 afforded selectively well-defined surface species SiOZr(NMe2) (η2NMeCH2). 2D solid-state NMR (1H- 13C HETCOR, Multiple Quantum) experiments have shown a unique structural rearrangement occurring on the immobilised zirconium bis methylamido ligand. © The Royal Society of Chemistry 2013.

  20. Structure elucidation of fucoidan composed of a novel tetrafucose repeating unit from sea cucumber Thelenota ananas.

    Science.gov (United States)

    Yu, Long; Xue, Changhu; Chang, Yaoguang; Xu, Xiaoqi; Ge, Lei; Liu, Guanchen; Wang, Yanchao

    2014-03-01

    Thelenota ananas is one of the most popular edible sea cucumber species consumed in China and some Southeast Asian countries. In this study, the delicate structure of fucoidan from T. ananas (Ta-FUC) was clarified. Oligosaccharides and low molecular weight polysaccharides of Ta-FUC were prepared by enzymatic degradation. Their structures, which retained primary structural features of Ta-FUC, were investigated using tandem mass spectrometry and nuclear magnetic resonance. As a result, Ta-FUC was found to be composed of a novel tetrafucose repeating unit [→3-α-L-Fucp-1→3-α-L-Fucp-1→3-α-L-Fucp2,4(OSO3(-))-1→3-α-L-Fucp2(OSO3(-))-1→]. Meanwhile, it was proven to possess a significant inhibitory effect on superoxide radicals with an IC50 of 17.46±0.14μg/ml. This effect was related to its sulphation pattern. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Elucidating the mechanisms of nanodiamond-promoted structural disruption of crystallised lipid.

    Science.gov (United States)

    Hughes, Zak E; Walsh, Tiffany R

    2016-10-12

    The removal or structural disruption of crystallised lipid is a pivotal but energy-intensive step in a wide range of industrial and biological processes. Strategies to disrupt the structure of crystallised lipid in aqueous solution at lower temperatures are much needed, where nanoparticle-based strategies show enormous promise. Using the aqueous tristearin bilayer as a model for crystallised lipid, we demonstrate that the synergistic use of surfactant and detonation nanodiamonds can depress the onset temperature at which disruption of the crystallised lipid structure occurs. Our simulations reveal the molecular-scale mechanisms by which this disruption takes place, indicating that the nanodiamonds serve a dual purpose. First, the nanodiamonds are predicted to facilitate delivery of surfactant to the lipid/water interface, and second, nanodiamond adsorption acts to roughen the lipid/water interface, enhancing ingress of surfactant into the bilayer. We find the balance of the hydrophobic surface area of the nanodiamond and the nanodiamond surface charge density to be a key determinant of the effectiveness of using nanodiamonds to facilitate lipid disruption. For the nanodiamond size considered here, we identify a moderate surface charge density, that ensures the nanodiamonds are neither too hydrophobic nor too hydrophilic, to be optimal.

  2. Rhizomes of Eremostachys laciniata: Isolation and Structure Elucidation of Chemical Constituents and a Clinical Trial on Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Abbas Delazar

    2013-08-01

    Full Text Available Purpose: The purpose of this study was the isolation and structure elucidation of chemical compounds from the rhizomes of Eremostachys laciniata (L Bunge (EL, an Iranian traditional medicinal herb with a thick root and pale purple or white flowers as well as the clinical studies on the therapeutic efficacy and safety of topical application of the EL extract in the management of some inflammatory conditions, e.g., arthritis, rheumatoid arthritis and septic arthritis (Riter’s syndrome. Methods: The structures of the isolated compounds were elucidated unequivocally on the basis of one and two dimensional NMR, UV and HR-FABMS spectroscopic data analyses. A single-blinded randomized clinical trial was carried out with the extract of the rhizomes of E. laciniata (EL to determine the efficacy and safety of the traditional uses of EL compared to that of piroxicam in treatment of inflammatory diseases, e.g., osteoarthritis, rheumatoid arthritis and Reiter’s syndrome. Results: Eleven iridoid glycosides, two phenylethanoids and two phytosterols were isolated and identified for the first time from the rhizomes of EL. After 14 days of treatment with the EL and piroxicam ointments, all groups showed significant improvements compared to the control groups. EL (5% ointment induced better initial therapeutic response than piroxicam (5% onitment. Conclusion: This clinical trial established that EL was suitable for topical applications as a safe and effective complementary therapy for inflammatory diseases.

  3. A thyrotropin-secreting pituitary adenoma as a cause of thyrotoxic periodic paralysis

    NARCIS (Netherlands)

    Alings, A. M.; Fliers, E.; de Herder, W. W.; Hofland, L. J.; Sluiter, H. E.; Links, T. P.; van der Hoeven, J. H.; Wiersinga, W. M.

    1998-01-01

    We describe a patient with thyrotoxic periodic paralysis (TPP) caused by a thyrotropin-secreting pituitary adenoma. The diagnosis TPP was based on the combination of episodes of reversible hypokalaemic paralysis, hyperthyroidism and electrophysiological findings. A thyrotropin-secreting pituitary

  4. Synthesis and structure elucidation of fluoro substituted guanidines as potential therapeutic agents

    Science.gov (United States)

    Ullah, Waseem; Imtiaz-ud-Din; Raheel, Ahmad; Badshah, Amin; Tahir, Muhammad Nawaz

    2017-09-01

    Six new fluoro -substituted guanidines (1-6) were synthesized and characterized by 1H and 13C NMR spectroscopy to ascertain the structures in solution (DMSO) besides the solid state information collected through FT IR and single crystal X-ray spectroscopy. The XRD data for (1-3) show that molecules are stabilized by strong intramolecular hydrogen bonding. The compounds were also preliminary bio-assayed for anti-microbial studies and show good to moderate activities. The anti-oxidant data revealed that o and p-substituted fluoro-guanidines enhances their DPPH scavenging ability significantly.

  5. Raman mapping in the elucidation of solid salt eutectic and near eutectic structures

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Kerridge, D. H.

    2002-01-01

    The distribution of the different components of solidified eutectic or near-eutectic salt mixtures (eutectics) was examined by use of Raman microscope mapping of the structures formed when these melts were slowly cooled. Seven binary and one ternary system were investigated. In most cases...... and the composition. When unidirectional cooling was applied it was possible for the system (KCl-Na2SO4, 60:40 mol/mol) to observe lamellar arrangements of the component phases, in an arrangement closely similar to what is frequently found among metallic or ceramic eutectics. Each area, conglomerate or lamellar, did...

  6. Structure elucidation and biomimetic synthesis of hostasinine A, a new benzylphenethylamine alkaloid from Hosta plantaginea.

    Science.gov (United States)

    Wang, Yue-Hu; Gao, Suo; Yang, Fu-Mei; Sun, Qian-Yun; Wang, Jun-Song; Liu, Hai-Yang; Li, Chun-Shun; Di, Ying-Tong; Li, Shun-Lin; He, Hong-Ping; Hao, Xiao-Jiang

    2007-12-06

    Hostasinine A (1), a benzylphenethylamine alkaloid with an unprecedented skeleton featuring a C-4-C-6 linkage and a nitrone moiety, was isolated from Hosta plantaginea. Its structure was established on the basis of spectroscopic data, and was further confirmed by single-crystal X-ray diffraction. The alkaloid was postulated biogenetically from haemanthidine via N-oxidation and aza-aldol-type condensation and was synthesized biomimetically. The inhibitory activities of 1 on acetylcholinesterase (AChE) and two tumor cell lines (K562 and A549) were also evaluated.

  7. Tannin structural elucidation and quantitative ³¹P NMR analysis. 2. Hydrolyzable tannins and proanthocyanidins.

    Science.gov (United States)

    Melone, Federica; Saladino, Raffaele; Lange, Heiko; Crestini, Claudia

    2013-10-02

    An unprecedented analytical method that allows simultaneous structural and quantitative characterization of all functional groups present in tannins is reported. In situ labeling of all labile H groups (aliphatic and phenolic hydroxyls and carboxylic acids) with a phosphorus-containing reagent (Cl-TMDP) followed by quantitative ³¹P NMR acquisition constitutes a novel fast and reliable analytical tool for the analysis of tannins and proanthocyanidins with significant implications for the fields of food and feed analyses, tannery, and the development of natural polyphenolics containing products.

  8. Structural elucidation and physicochemical properties of an organic NLO crystal: 4-Nitrotoluene-2-sulphonic acid dihydrate

    Science.gov (United States)

    Sangeetha, K.; Guru Prasad, L.; Mathammal, R.

    2018-03-01

    4-nitrotoluene-2-sulphonic acid dihydrate single crystals have been developed using slow evaporation technique in methanol. Lattice parameters of the NTSAD crystal have been calculated and it confirms the grown material. The intermolecular interactions are studied from the 3D Hirshfeld surface analysis and 2D fingerprint plots. The NMR spectral analysis has been carried out to confirm the molecular structure of the grown material. Optical properties have been obtained from UV-VIS spectral analysis and photoluminescence studies. Frequency conversion property of the NTSAD crystal was investigated with the aid of Kurtz and Perry method.

  9. Structure-Function Elucidation of Antioxidative and Prooxidative Activities of the Polyphenolic Compound Curcumin

    Directory of Open Access Journals (Sweden)

    Parth Malik

    2014-01-01

    Full Text Available Phenolic compounds have been very well known for their antioxidant properties, owing to their unique ability to act as free radical scavengers which, in turn, is an outstanding attribute of their unique biochemical structure. Recent accumulating lines of evidence inculcate sustainable interest and curiosity towards the chemoprotective nature of the natural polyphenolic compound curcumin (diferuloylmethane against oxidative stress-mediated disorders. Curcumin is naturally found as a constituent of dietary spices called turmeric, extracted from the plant Curcuma longa. However, like every phenolic antioxidant, curcumin possesses a concentration and medium dependent anti- and pro-oxidant behaviour. A detailed study of the structure-function analysis and the understanding of the mode of action of curcumin as well as its chemical analogues is thus essential to understand the selective biochemical consequences of curcumin. Moreover, the presence of transition metal ions, route of administration, and localized tissue are also the vital decisive factors to determine curcumin behaviour. With this viewpoint, this paper sheds lights on the medium dependent prooxidative and antioxidative attributes of curcumin. Further, with respect to emergence of nanocarriers, a brief discussion focusing on the biochemical effect exertion of curcumin chiefly due to targeted and slow release has also been added towards the end.

  10. Fatty acid synthase inhibitors from plants: isolation, structure elucidation, and SAR studies.

    Science.gov (United States)

    Li, Xing-Cong; Joshi, Alpana S; ElSohly, Hala N; Khan, Shabana I; Jacob, Melissa R; Zhang, Zhizheng; Khan, Ikhlas A; Ferreira, Daneel; Walker, Larry A; Broedel, Sheldon E; Raulli, Robert E; Cihlar, Ronald L

    2002-12-01

    Fatty acid synthase (FAS) has been identified as a potential antifungal target. FAS prepared from Saccharomyces cerevisiae was employed for bioactivity-guided fractionation of Chlorophora tinctoria,Paspalum conjugatum, Symphonia globulifera, Buchenavia parviflora, and Miconia pilgeriana. Thirteen compounds (1-13), including three new natural products (1, 4, 12), were isolated and their structures identified by spectroscopic interpretation. They represented five chemotypes, namely, isoflavones, flavones, biflavonoids, hydrolyzable tannin-related derivatives, and triterpenoids. 3'-Formylgenistein (1) and ellagic acid 4-O-alpha-l-rhamnopyranoside (9) were the most potent compounds against FAS, with IC(50) values of 2.3 and 7.5 microg/mL, respectively. Furthermore, 43 (14-56) analogues of the five chemotypes from our natural product repository and commercial sources were tested for their FAS inhibitory activity. Structure-activity relationships for some chemotypes were investigated. All these compounds were further evaluated for antifungal activity against Candida albicans and Cryptococcus neoformans. Although there were several antifungal compounds in the set, correlation between the FAS inhibitory activity and antifungal activity could not be defined.

  11. Spreading properties of cosmetic emollients: Use of synthetic skin surface to elucidate structural effect.

    Science.gov (United States)

    Douguet, Marine; Picard, Céline; Savary, Géraldine; Merlaud, Fabien; Loubat-Bouleuc, Nathalie; Grisel, Michel

    2017-06-01

    The study focuses on the impact of structural and physicochemical properties of emollients on their spreadability. Fifty-three emollients, among which esters, silicones, vegetable and mineral oils, have been characterized. Their viscosity, surface tension, density and spreadability have been measured. Vitro-skin ® , an artificial skin substitute, was used as an artificial porous substrate to measure spreadability. Two different methods have been selected to characterize spreadability, namely contact angle and spreading value. Dynamic contact angle measurements showed that emollient spreadability is first governed by spontaneous spreading and that, in a second phase, absorption and migration into the porous substrate becomes the driver of the extension of the spreading area. Statistical analysis of physicochemical and spreading value data revealed that viscosity has a major impact on the spreading behavior of emollients whatever their chemical type. A special emphasis was placed on the ester family in which chemical diversity is very wide. The results highlighted a difference between "high viscosity esters" for which viscosity is the main factor impacting spreadability and "low viscosity esters" for which structural variations (mono/diester, saturated/unsaturated chain, linear/branched chain) have to be considered in addition to viscosity. Linear regressions were used to express spreading value as a function of viscosity for each of the four emollient families tested (esters, silicones, vegetable and mineral oils). These regressions allowed the development of reliable predictive models as a powerful tool for formulators to forecast spreadability of emollients. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Elucidating the role of transcription in shaping the 3D structure of the bacterial genome

    Science.gov (United States)

    Brandao, Hugo B.; Wang, Xindan; Rudner, David Z.; Mirny, Leonid

    Active transcription has been linked to several genome conformation changes in bacteria, including the recruitment of chromosomal DNA to the cell membrane and formation of nucleoid clusters. Using genomic and imaging data as input into mathematical models and polymer simulations, we sought to explore the extent to which bacterial 3D genome structure could be explained by 1D transcription tracks. Using B. subtilis as a model organism, we investigated via polymer simulations the role of loop extrusion and DNA super-coiling on the formation of interaction domains and other fine-scale features that are visible in chromosome conformation capture (Hi-C) data. We then explored the role of the condensin structural maintenance of chromosome complex on the alignment of chromosomal arms. A parameter-free transcription traffic model demonstrated that mean chromosomal arm alignment can be quantitatively explained, and the effects on arm alignment in genomically rearranged strains of B. subtilis were accurately predicted. H.B. acknowledges support from the Natural Sciences and Engineering Research Council of Canada for a PGS-D fellowship.

  13. Monoclonal Antibodies to the Thyrotropin Receptor

    Directory of Open Access Journals (Sweden)

    Takao Ando

    2005-01-01

    Full Text Available The thyrotropin receptor (TSHR is a seven transmembrane G-protein linked glycoprotein expressed on the thyroid cell surface and which, under the regulation of TSH, controls the production and secretion of thyroid hormone from the thyroid gland. This membrane protein is also a major target antigen in the autoimmune thyroid diseases. In Graves' disease, autoantibodies to the TSHR (TSHR-Abs stimulate the TSHR to produce thyroid hormone excessively. In autoimmune thyroid failure, some patients exhibit TSHR-Abs which block TSH action on the receptor. There have been many attempts to generate human stimulating TSHR-mAbs, but to date, only one pathologically relevant human stimulating TSHR-mAb has been isolated. Most mAbs to the TSHR have been derived from rodents immunized with TSHR antigen from bacteria or insect cells. These antigens lacked the native conformation of the TSHR and the resulting mAbs were exclusively blocking or neutral TSHR-mAbs. However, mAbs raised against intact native TSHR antigen have included stimulating mAbs. One such stimulating mAb has demonstrated a number of differences in its regulation of TSHR post-translational processing. These differences are likely to be reflective of TSHR-Abs seen in Graves' disease.

  14. Thyrotropin interaction with high-density lipoproteins.

    Science.gov (United States)

    Bifulco, M; Saroff, H A; Kohn, L D; Aloj, S M

    1985-07-09

    Human high-density lipoproteins (HDL), but not other lipoprotein classes, bind bovine thyrotropin (TSH) with moderately high affinity. Binding of 125I-labeled HDL to TSH has been measured in a solid-phase assay; it is saturable and can be displaced by unlabeled HDL but not by other lipoproteins or bovine serum albumin. The interaction of HDL with TSH has been studied by fluorescence spectroscopy: HDL specifically modifies the fluorescence properties of the biologically active dansyl derivative (DNS, (5-dimethyl-aminonaphtalene-1-sulfonyl) chloride) of TSH (DNS-TSH) causing a 12 nm shift to lower wavelength of the emission maximum, a two-fold increase of the quantum yield and a significant increase of fluorescence polarization. The primary site of TSH binding on the HDL particle is likely to be located on its protein moieties, since other lipoprotein classes, which share similar lipids with HDL, do not bind TSH. 125I-labeled apolipoprotein A-I binds TSH in the solid-phase assay and titration of DNS-TSH with apolipoprotein A-I causes perturbations nearly identical to those observed with intact HDL. One HDL particle has at least 12 binding sites for TSH with an association constant, K = 10(7) M-1 whereas one apolipoprotein A-I molecule binds one or two TSH molecules with an association constant slightly lower than that for HDL (K = 10(6) M-1). The lipid moieties of HDL also appears to be perturbed by the interaction with TSH.

  15. Antineoplastic agents. 398. Isolation and structure elucidation of cephalostatins 18 and 19.

    Science.gov (United States)

    Pettit, G R; Tan, R; Xu, J; Ichihara, Y; Williams, M D; Boyd, M R

    1998-07-01

    Continued investigation of murine leukemia (P-388) active fractions from the African marine worm Cephalodiscus gilchristi has resulted in the discovery of cephalostatins 18 (1b) and 19 (1c). The structures were determined by interpretation of their highfield (500 MHz) 1H, 13C, and 2D NMR and HRMS. Both of these new methoxy steroidal alkaloids exhibited strong activity against the murine P-388 lymphocytic leukemia cell line (ED50 ca. 10(-3) microg/mL), a mini panel of human cancer cell lines (GI50 <10(-3) microg/mL), and the U.S. National Cancer Institute's 60 human cancer cell line panel (mean panel GI50 ca. 10(-9) M).

  16. Amperometric Determination of Bismuth Using Gallacetophenone Phenylhydrazone with the Structural Elucidation of Complex

    Directory of Open Access Journals (Sweden)

    D. Venkataramana Reddy

    2010-01-01

    Full Text Available Gallacetophenone phenylhydrazone (GPPH has been used as an analytical reagent for amperometric determination of bismuth. Bismuth is quantitatively determined by GPPH at pH 3.0-6.0. After studying the polarographic behaviour of GPPH and bismuth(III at dropping mercury electrode (DME, applied potential was fixed at -0.4v vs. saturated calomel electrode (SCE. The method was applied for the determination of bismuth in wood’s alloy. The composition of the complex corresponds to the formula Bi(C14 H14 O3 N22. The structure of the complex was arrived from the micro analytical data of the solid complex, thermogravimetric and differential thermal analysis curves and also from the infrared spectra of the complex.

  17. Production, Structural Elucidation, and In Vitro Antitumor Activity of Trehalose Lipid Biosurfactant from Nocardia farcinica Strain.

    Science.gov (United States)

    Christova, Nelly; Lang, Siegmund; Wray, Victor; Kaloyanov, Kaloyan; Konstantinov, Spiro; Stoineva, Ivanka

    2015-04-01

    The objective of this study was to isolate and identify the chemical structure of a biosurfactant produced by Nocardia farcinica strain BN26 isolated from soil, and evaluate its in vitro antitumor activity on a panel of human cancer cell lines. Strain BN26 was found to produce glycolipid biosurfactant on n-hexadecane as the sole carbon source. The biosurfactant was purified using medium-pressure liquid chromatography and characterized as trehalose lipid tetraester (THL) by nuclear magnetic resonance spectroscopy and mass spectrometry. Subsequently, the cytotoxic effects of THL on cancer cell lines BV-173, KE-37 (SKW-3), HL-60, HL-60/DOX, and JMSU-1 were evaluated by MTT assay. It was shown that THL exerted concentration-dependent antiproliferative activity against the human tumor cell lines and mediated cell death by the induction of partial oligonucleosomal DNA fragmentation. These findings suggest that THL could be of potential to apply in biomedicine as a therapeutic agent.

  18. Structure elucidation of new compounds from acidic treatment of the progestins gestodene and drospirenone.

    Science.gov (United States)

    Colombo, Diego; Bombieri, Gabriella; Lenna, Roberto; Marchini, Nicoletta; Modica, Emilia; Scala, Antonio

    2006-08-01

    Gestodene acidic treatment afforded a single rearrangement product, namely 13-beta-ethyl-18,19-dinorpregna-4,14,16-trien-3,20-dione 3, which was originated through HCl-catalyzed Rupe rearrangement. Drospirenone acidic treatment yielded two epimeric lactones by addition of HCl to the 6beta,7beta-cyclopropane ring, namely 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17beta-pregn-4-ene-21,17-carbolactone 4 and 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17alpha-pregn-4-ene-21,17-carbolactone 5. The structure of the compounds was assessed by spectroscopic and crystallographic methods.

  19. Isolation, Structure Elucidation and Total Synthesis of Lajollamide A from the Marine Fungus Asteromyces cruciatus

    Directory of Open Access Journals (Sweden)

    Johannes F. Imhoff

    2012-12-01

    Full Text Available The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1, along with the known compounds regiolone (2, hyalodendrin (3, gliovictin (4, 1N-norgliovicitin (5, and bis-N-norgliovictin (6. The planar structure of lajollamide A (1 was determined by Nuclear Magnetic Resonance (NMR spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1 was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1 of the l-leucine and l-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.

  20. Isolation, Structure Elucidation and Total Synthesis of Lajollamide A from the Marine Fungus Asteromyces cruciatus

    Science.gov (United States)

    Gulder, Tobias A. M.; Hong, Hanna; Correa, Jhonny; Egereva, Ekaterina; Wiese, Jutta; Imhoff, Johannes F.; Gross, Harald

    2012-01-01

    The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), 1N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the L-leucine and L-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems. PMID:23342379

  1. Enantiomeric characterization and structure elucidation of LH601A using vibrational circular dichroism spectroscopy

    Science.gov (United States)

    Shen, Jian; Magesh, Sadagopan; Chen, Lin; Hu, Longqin; He, Yanan

    2018-03-01

    LH601A is a novel non-reactive chiral molecule inhibiting Keap1-Nrf2 protein-protein interaction. The absolute configuration (AC) was independently determined in this study using vibrational circular dichroism (VCD) spectroscopy. Because of band overlapping and broadening in the IR spectrum, a direct VCD spectrum comparison method is devised without the conventional IR band alignment. Being an unbiased AC inquiry, all possible chiralities are evaluated based on the statistical analysis of VCD similarity, Sv. The AC of three-center stereoisomer LH601A is unambiguously assigned to (S,R,S). A comparative study was also carried out to investigate the structural and energy differences of calculated conformers using the polarized continuum model of dimethyl sulfoxide.

  2. X-ray Crystal Structures Elucidate the Nucleotidyl Transfer Reaction of Transcript Initiation Using Two Nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    M Gleghorn; E Davydova; R Basu; L Rothman-Denes; K Murakami

    2011-12-31

    We have determined the X-ray crystal structures of the pre- and postcatalytic forms of the initiation complex of bacteriophage N4 RNA polymerase that provide the complete set of atomic images depicting the process of transcript initiation by a single-subunit RNA polymerase. As observed during T7 RNA polymerase transcript elongation, substrate loading for the initiation process also drives a conformational change of the O helix, but only the correct base pairing between the +2 substrate and DNA base is able to complete the O-helix conformational transition. Substrate binding also facilitates catalytic metal binding that leads to alignment of the reactive groups of substrates for the nucleotidyl transfer reaction. Although all nucleic acid polymerases use two divalent metals for catalysis, they differ in the requirements and the timing of binding of each metal. In the case of bacteriophage RNA polymerase, we propose that catalytic metal binding is the last step before the nucleotidyl transfer reaction.

  3. Structure elucidation and biological activity of antibacterial compound from Micromonospora auratinigra, a soil Actinomycetes.

    Science.gov (United States)

    Talukdar, M; Bordoloi, M; Dutta, P P; Saikia, S; Kolita, B; Talukdar, S; Nath, S; Yadav, A; Saikia, R; Jha, D K; Bora, T C

    2016-10-01

    The aim of this study was to isolate and characterize the bioactive compound of Micromonospora auratinigra, HK-10 and its antibacterial inhibitory mechanism. An oily bioactive compound was extracted from HK-10 (GenBank accession no. JN381554) and found to have promising antibacterial activity. The compound was characterized as 2-methylheptylisonicotinate (1) by (1) H, (13) C NMR and mass spectroscopy. Minimum inhibitory concentration (MIC) of this molecule was tested by micro broth dilution method and was found to be 70, 40, 80, 60, 60 and 50 μg for Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Echerichia coli, Pseudomonas aeruginosa and Mycobacterium abscessus respectively. The effects of compound 1 were studied on bacterial membrane structure using scanning electron microscopy. The results indicated a membrane-disrupting mechanism, resulting in the dysfunction of the cytoplasmic membrane structure and cell death of the pathogenic bacterial strains. Kinetics of growth of the test organisms was also analysed and indicated 2-methylheptylisonicotinate 1 as a bactericidal agent. Furthermore, we have studied the binding affinity of 1 towards different membrane proteins of pathogenic bacteria by in silico analysis. 2-methylheptylisonicotinate was isolated from M. auratinigra, a rare actinobacterial strain possessing antibacterial activity through a membrane-disrupting mechanism, and has MICs similar to standard antibiotic neomycin sulphate. It is the first report about a strain of M. auratinigra, isolated from Indo-Burma biodiversity hotspot of North-east India with new antimicrobial activities. In silico studies have also supported these results performed on various membrane targets of pathogenic bacteria. The antibacterial potential of M. auratinigra is reported for the first time. The results indicate the possible use of 2-methylheptylisonicotinate as a source of antibacterial agent against dreaded human pathogens. © 2016 The Society for Applied

  4. Structural–Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work

    Science.gov (United States)

    Kleinau, Gunnar; Worth, Catherine L.; Kreuchwig, Annika; Biebermann, Heike; Marcinkowski, Patrick; Scheerer, Patrick; Krause, Gerd

    2017-01-01

    The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to

  5. Structural–Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work

    Directory of Open Access Journals (Sweden)

    Gerd Krause

    2017-04-01

    Full Text Available The thyroid-stimulating hormone receptor (TSHR is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs. TSHR and its endogenous ligand thyrotropin (TSH are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016 concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other

  6. Isolation and structure elucidation of pectic polysaccharide from rose hip fruits (Rosa canina L.).

    Science.gov (United States)

    Ognyanov, Manol; Remoroza, Connie; Schols, Henk A; Georgiev, Yordan; Kratchanova, Maria; Kratchanov, Christo

    2016-10-20

    A pectic polysaccharide from rose hip (RH) fruits has been obtained by extraction with 1% aqueous citric acid. It was found that the polysaccharide fraction mainly consisted of galacturonic acid (45.5%) next to galactose (5.5%) and arabinose (4.7%). RH pectin is having a relatively high degree of methylesterification (62%) and acetylation (10%) and consists of different molecular weight populations in the range of 10-100kDa. Enzymatic fingerprinting was performed using a combination of pectin lyase (PL) and endo-polygalacturonase. Detailed information about the structure and level of galacturonic acid oligomers released was obtained using LC-HILIC-MS/ELSD and HPAEC. Predominantly, unsaturated and methyl-esterified oligomers (DP 3-5) were released indicating that high proportions of methylesterified 'PL degradable' areas were present within the pectin. The data revealed that homogalacturonan is the main building block of the extracted pectin and consists of long methylesterified/acetylated GalA sequences interspersed with small blocks of non-methyl-esterified GalA units. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Isolation and Structure Elucidation of Uncommon Secondary Metabolites from Cistus salviifolius L.

    Directory of Open Access Journals (Sweden)

    Perihan Gürbüz

    2015-01-01

    Full Text Available To our knowledge this is the first report on the isolation of a flavonoid glycoside: quercetin 3-O-α-arabinopyranoside (5, two phenylbutanon glycosides: 4-(4'-O-[6''-O-galloyl-β-galactopyranosyl]-3'-hydroxyphenyl-butan-2-on (8, 4-(3'-O-β-glucopyranosyl-4'-hydroxyphenyl-butan-2-on (9, one phloroglucinol glycoside: 1-O-β-glucopyranosyl-3,5-dimethoxybenzene (10 and a steroid glycoside: sitosterol-3-O-(6''-O-butanoyl-β-galactopyranoside (14 from the Cistus species (Cistaceae. Additional to these compounds three flavonol aglycones: kaempferol (1, quercetin (2, myricetin (3; three flavonoid glycosides; kaempferol 3-O-β-(6''-O-trans-p-coumaroyl-glucopyranoside (4, quercetin 3-O-β-galactopyranoside (6, myricetin 3-O-β-galactopyranoside (7; one phloroglucinol glycoside: 1-O-β-glucopyranosyl-3,5-dimethoxybenzene (11; one steroid aglycone: β-sitosterol (12; one steroid glycoside: Sitosterol-3-O- β-glucopyranoside (13 were isolated from the aerial parts of the Cistus salviifolius L.. Their structures were identified using spectral methods (UV, IR, 1D- and 2D-NMR, and ESI-MS.

  8. Synthesis and Elucidation Structure of Tetrakis-diphenylaminecopper(II) Chloride Hexahydrate

    Science.gov (United States)

    Syaima, H.; Rahardjo, S. B.; Suciningrum, E.

    2017-11-01

    CuCl2·2H2O with diphenylamine formed a complex compound in 1:4-mole ratio of metal to the ligand in methanol. Its structural properties were investigated by employing metal content analysis by Atomic Absorption Spectroscopy (AAS), magnetic susceptibility, UV-vis and FTIR spectroscopy. The forming of the complex was indicated by shifting of UV-Vis spectra. The result of analysis Cu(II) in the complex showed empirical formula of the complex were Cu(diphenylamine)4Cl2(H2O)6. The electrical conductivity of complex showed the charge ratio of cation and anion = 2:1. Finally, the proposed formula of the complex was [Cu(diphenylamine)4]Cl2·6H2O. Based on infrared spectra, it was revealed that diphenylamine existed as monodentate bind to copper(II) through the functional group of N-H. The electronic spectral study of the complex showed three transition peaks on 861, 592, and 419 nm corresponding to the 2B1g → 2A1g, 2B1g → 2B2g dan 2B1g → 2Eg transitions. The complex was paramagnetic and indicated that ligands form square planar geometry around the Cu(II).

  9. Structure elucidation and antioxidant activity of a novel polysaccharide isolated from Boletus speciosus Forst.

    Science.gov (United States)

    Ding, Xiang; Hou, Yi-ling; Hou, Wan-ru

    2012-04-01

    In this study, a novel heteropolysaccharide was isolated from the fruiting bodies of Boletus speciosus Forst through DEAE-cellulose column and Sephadex G-200 column. The Boletus speciosus Forst polysaccharide (BSFP-1) had a molecular weight of 1.33×10(4) Da and was mainly composed of l-Man and d-Gal which ratios were 2:1. Structural features of Boletus speciosus Forst polysaccharide (BSFP-1) were investigated by a combination of total hydrolysis, methylation analysis, gas chromatography-mass spectrometry (GC-MS), infrared (IR) spectra and nuclear magnetic resonance (NMR) spectroscopy. The results indicated that Boletus speciosus Forst polysaccharide (BSFP-1) had a backbone of (1→4)-α-l-mannopyranose residues which branches at O-6 based on the experimental results. The branches were mainly composed of one with →1)-α-d-galactopyranose residue. The antioxidant activity of BSFP-1 was evaluated with two biochemical methods, including 1,1-diphenyl-2-picrylhydrazyl (DPPH(-)) radical scavenging, scavenging activity of 2,2'-azino-bis(3-ethylbenzthiazoline-6-suphonic acid)diammonium (ABTS(+)) radical. The results indicated that BSFP-1 showed strong antioxidant. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Dalglish G. de; Almeida, Cecilia M.C. de; Silva, Consuelo Y.Y. e; Arruda, Mara S.P.; Arruda, Alberto C., E-mail: yumilton@yahoo.com.br [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Lab. de Cromatografia Liquida; Lopes, Dielly C.F.; Yamada, Elizabeth S.; Costa, Edmar T. da; Silva, Milton N. da [Hospital Universitario Barros Barreto, Belem, PA (Brazil). Lab. de Neuropatologia Experimental

    2012-10-15

    Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2{sup ,}2{sup -}dimethylchromene-(5''6''6,7)- dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'', 2''-dimethylchromene-(5{sup ,}6{sup :}6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy- 6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 {+-} 1.6%) when the cultures were exposed to 30 nmol L{sup -1} rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 {mu}g mL{sup -1}) and 30 nmol L{sup -1} rotenone resulted in values of cell viability similar to control groups (99.6 {+-} 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction. (author)

  11. Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Dalglish G. de; Almeida, Cecilia M.C. de; Silva, Consuelo Y.Y. e; Arruda, Mara S.P.; Arruda, Alberto C.; Silva, Milton N. da, E-mail: yumilton@yahoo.com.br [Laboratorio de Cromatografia Liquida, Universidade Federal do Para, Guama, Belem-PA (Brazil); Lopes, Dielly C.F.; Yamada, Elizabeth S.; Costa, Edmar T. da; MFilho, Arnaldo Jorge [Laboratorio de Neuropatologia Experimental, Hospital Universitario Barros Barreto, Guama, Belem-PA (Brazil)

    2012-11-15

    Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2'',2''dimethylchromene-(5''6'':6,7)- dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'',2''-dimethylchromene-(5'',6'':6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy- 6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 {+-} 1.6%) when the cultures were exposed to 30 nmol L{sup -1}rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 {mu}g mL{sup -1}) and 30 nmol L{sup -1} rotenone resulted in values of cell viability similar to control groups (99.6 {+-} 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction. (author)

  12. Sulfated phenolic compounds from Limonium caspium: Isolation, structural elucidation, and biological evaluation

    Science.gov (United States)

    Gadetskaya, Anastassiya V.; Tarawneh, Amer H.; Zhusupova, Galiya E.; Gemejiyeva, Nadezhda G.; Cantrell, Charles L.; Cutler, Stephen J.; Ross, Samir A.

    2016-01-01

    Three new compounds, (2S,3S)-5-methyldihydromyricetin (1), (2S,3S)-5-methyldihydromyricetin-3′-O-sulfate (2) and β-D-glucopyranoside, 3-methyl, but-3-en-1-yl 4-O-α-L-rhamnopyranosyl (3) have been isolated from the Limonium caspium, together with dihydromyricetin (4), dihydromyricetin-3′-O-sulfate (5), myricetin-3′-O-sulfate (6), 5-methylmyricetin (7), myricetin (8), myricetin-3-O-β-glucoside (9), as well as phloridzin (10), and tyramine (11). Compounds 5 and 6 were isolated for the first time as acids. This is the first report of all these compounds from this plant. Their structures were established by extensive NMR studies (1H NMR, 13C NMR, DEPT, 1H–1H COSY, HSQC, HMBC) as well as HRESIMS. All isolated compounds were evaluated for their antibacterial, antifungal, antimalarial and antileishmanial activities. Compounds 7, 8 and 9 exhibited good antifungal activity against Candida glabrata with IC50 values of 6.79, 15.37 and 8.53 μg/mL, respectively. Compound 8 displayed significant antimalarial activity against resistant and sensitive strains of Plasmodium falciparum with IC50 values of 1.82 and 1.51 μg/mL, respectively. Compounds 1, 4, 6, 8 and 9 showed excellent activity against Trypanosoma brucei with IC50 values of 6.93, 9.65, 8.52, 7.67 and 6.31 μg/mL, respectively. To date, this is the first report on the phytochemical and biological activity of secondary metabolites from L. caspium. PMID:26025854

  13. [Isolation and structure elucidation of further new saponins from Solidago canadensis].

    Science.gov (United States)

    Reznicek, G; Jurenitsch, J; Freiler, M; Korhammer, S; Haslinger, E; Hiller, K; Kubelka, W

    1992-02-01

    Four new main saponins (canadensis-saponins 5-8) (compounds 5-8) were isolated from Solidago canadensis L. (Asteraceae). Using GC/MS, FAB-MS, and mainly 2D-NMR techniques their structures were identified as 3-O-[beta-D-glucopyranosyl(1----3)-beta-D- glucopyranosyl]-28-O-[beta-D-galactopyranosyl(1----2)-alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D-apio -D- furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl-(1----)]-bayog enin(5),3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[beta-D- galactopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta-D- xylopyranosyl-(1----4)-[beta-D-xylopyranosyl-(1----3)]-alpha-L- rhamnopyranosyl-(1----2)-[beta-D-apio-D-furanosyl-(1----3)]- arabinopyranosyl-(1----)]bayogenin(6),3-O-[beta-D-glucopy ran osyl-(1----3)- beta-D-glucopyranosyl]-28-O-[beta-D-galactopyranosyl-(1----2)- alpha-L-rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[alpha-L- rhamnopyranosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl-(1----)]-++ +bayogenin (7), and 3-O-[beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-[O- beta-D-galactopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta-D - xylopyranosyl-(1----4)-[beta-D-xylopyranosyl-(1----3)]-alpha-L- rhamnopyranosyl-(1----2)-[alpha-L-rhamnopyranosyl-(1----3)]arabinopyr anosyl - (1----)[-bayogenin (8).

  14. Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties

    International Nuclear Information System (INIS)

    Oliveira, Dalglish G. de; Almeida, Cecilia M.C. de; Silva, Consuelo Y.Y. e; Arruda, Mara S.P.; Arruda, Alberto C.; Silva, Milton N. da; Lopes, Dielly C.F.; Yamada, Elizabeth S.; Costa, Edmar T. da; MFilho, Arnaldo Jorge

    2012-01-01

    Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2'',2''dimethylchromene-(5''6'':6,7)- dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'',2''-dimethylchromene-(5'',6'':6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy- 6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 ± 1.6%) when the cultures were exposed to 30 nmol L -1 rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 μg mL -1 ) and 30 nmol L -1 rotenone resulted in values of cell viability similar to control groups (99.6 ± 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction. (author)

  15. Elucidating the interaction between light competition and herbivore feeding patterns using functional-structural plant modelling.

    Science.gov (United States)

    de Vries, Jorad; Poelman, Erik H; Anten, Niels; Evers, Jochem B

    2018-01-24

    Plants usually compete with neighbouring plants for resources such as light as well as defend themselves against herbivorous insects. This requires investment of limiting resources, resulting in optimal resource distribution patterns and trade-offs between growth- and defence-related traits. A plant's competitive success is determined by the spatial distribution of its resources in the canopy. The spatial distribution of herbivory in the canopy in turn differs between herbivore species as the level of herbivore specialization determines their response to the distribution of resources and defences in the canopy. Here, we investigated to what extent competition for light affects plant susceptibility to herbivores with different feeding preferences. To quantify interactions between herbivory and competition, we developed and evaluated a 3-D spatially explicit functional-structural plant model for Brassica nigra that mechanistically simulates competition in a dynamic light environment, and also explicitly models leaf area removal by herbivores with different feeding preferences. With this novel approach, we can quantitatively explore the extent to which herbivore feeding location and light competition interact in their effect on plant performance. Our results indicate that there is indeed a strong interaction between levels of plant-plant competition and herbivore feeding preference. When plants did not compete, herbivory had relatively small effects irrespective of feeding preference. Conversely, when plants competed, herbivores with a preference for young leaves had a strong negative effect on the competitiveness and subsequent performance of the plant, whereas herbivores with a preference for old leaves did not. Our study predicts how plant susceptibility to herbivory depends on the composition of the herbivore community and the level of plant competition, and highlights the importance of considering the full range of dynamics in plant-plant-herbivore interactions

  16. Structural and Functional Elucidation of Peptide Ts11 Shows Evidence of a Novel Subfamily of Scorpion Venom Toxins

    Science.gov (United States)

    Cremonez, Caroline M.; Maiti, Mohitosh; Peigneur, Steve; Cassoli, Juliana Silva; Dutra, Alexandre A. A.; Waelkens, Etienne; Lescrinier, Eveline; Herdewijn, Piet; de Lima, Maria Elena; Pimenta, Adriano M. C.; Arantes, Eliane C.; Tytgat, Jan

    2016-01-01

    To date, several families of peptide toxins specifically interacting with ion channels in scorpion venom have been described. One of these families comprise peptide toxins (called KTxs), known to modulate potassium channels. Thus far, 202 KTxs have been reported, belonging to several subfamilies of KTxs (called α, β, γ, κ, δ, and λ-KTxs). Here we report on a previously described orphan toxin from Tityus serrulatus venom, named Ts11. We carried out an in-depth structure-function analysis combining 3D structure elucidation of Ts11 and electrophysiological characterization of the toxin. The Ts11 structure is highlighted by an Inhibitor Cystine Knot (ICK) type scaffold, completely devoid of the classical secondary structure elements (α-helix and/or β-strand). This has, to the best of our knowledge, never been described before for scorpion toxins and therefore represents a novel, 6th type of structural fold for these scorpion peptides. On the basis of their preferred interaction with voltage-gated K channels, as compared to all the other targets tested, it can be postulated that Ts11 is the first member of a new subfamily, designated as ε-KTx. PMID:27706049

  17. Preparation and structural elucidation of the picolinyl ester of aldosterone for liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Tadokoro, Yumiko; Takahashi, Madoka; Numazawa, Mitsuteru

    2008-06-01

    Treatment of aldosterone with 35% HCl in EtOH or in MeOH followed by the picolinyl derivatization gave the picolinyl derivative of aldosterone-ethyl ether, 8, or methyl ether, 9, as a single and well-shaped liquid chromatographic peak. Picolinyl derivatization of aldosterone produced 21-picolinyl derivative of 18,20-anhydro-hemiacetal derivatives, 6, with poor chromatographic peak with wide half-width. Further conversion of 6 to 8 required long reaction time (>4 h). Structure of each picolinyl or alkyl ether-picolinyl derivative, was carefully elucidated by nuclear magnetic resonance spectroscopy, electron ionization mass spectrometry and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Enhancement of sensitivity (approximately 10-fold) in positive-LC-ESI-MS/MS of aldosterone was confirmed by the use of the alkyl ether-picolinyl derivatization when compared to the underivatized molecule.

  18. POSITIVE THYROTROPIN RECEPTOR ANTIBODIES IN PATIENTS WITH TRANSIENT THYROTOXICOSIS.

    Science.gov (United States)

    Angell, Trevor E; Van Benschoten, Olivia; Cohen, David A; Haas, Andrea V; Alexander, Erik K; Marqusee, Ellen

    2018-04-06

    Thyrotropin (TSH) receptor antibody (TRAb) testing is considered accurate for the diagnosis of Graves' disease (GD), and had been identified rarely in thyrotoxic patients without GD. We describe four patients with transient thyrotoxicosis and positive TRAb to highlight this clinical possibility. Patient demographics, symptoms, laboratory findings, and time to resolution of thyrotoxicosis are summarized. TRAb testing was performed by either a third-generation thyrotropin binding inhibitory immunoglobulin competitive binding assay (TBII) or a thyroid stimulating antibody bioassay (TSI) from either Mayo Clinic Laboratory or Quest Diagnostics. Four patients with transient thyrotoxicosis and positive TRAb testing were identified. Of these, three were female and median age was 44 years (range 25-49). Median symptom duration at evaluation was 6.5 weeks (range 3-12). No patient had any clinical manifestations unique to GD or had exposure to biotin, thyroid hormone, supplements, iodine, or relevant medications. The TSH was TSI, which was elevated less than twice the upper limit of the reference range in all cases, and one patient had a strongly positive TBII. None of the patients were treated with thionamides or RAI. Spontaneous resolution occurred in all patients at a median of 5.5 weeks (range 2-14.4). These cases demonstrate that TSI or TBII may be present in thyrotoxic patients with transient thyrotoxicosis. For clinically stable patients presenting without pathognomonic evidence of GD, mildly elevated TRAb results may require cautious interpretation and alterative diagnostic testing or close monitoring should be considered. ATA = American Thyroid Association; GD = Graves' disease; FT4 = free thyroxine; RAI = Radioactive iodine; RAIU = radioactive iodine uptake; TFT = thyroid function tests; TPO = thyroperoxidase; TRAb = Thyrotropin receptor antibody; TSH = Thyroid stimulating hormone or thyrotropin; TSHR = thyrotropin receptor; TT3 = Total triiodothyronine; TT4 = Total

  19. Circulating thyrotropin is upregulated by estradiol

    Directory of Open Access Journals (Sweden)

    Salvatore Benvenga

    2018-03-01

    Full Text Available After encountering two women with serum thyrotropin (TSH levels greater in periovulatory phase than in other days of the menstrual cycle, we hypothesized that TSH levels could be sensitive to changes in circulating estrogens in women.The objective of this study was to evaluate whether serum TSH increases after an induced acute increase of serum estradiol, and compare serum TSH increase with that of prolactin (PRL which is a classic estradiol-upregulated pituitary hormone.In this retrospective study, we resorted to stored frozen sera from 55 women who had undergone the GnRH agonist (buserelin-acute stimulation test of ovarian steroidogenesis. This test, that is preceded by dexamethasone administration to suppress adrenal steroidogenesis, had been performed to show an increased buserelin-stimulated response of 17-hydroxyprogesterone, a response that is frequent in polycystic ovary syndrome. Fifty-five women had enough serum volume at pertinent times (first observation early in the follicular phase and all times of the test to permit assay of serum estradiol, TSH and PRL.Before dexamethasone administration, estradiol averaged 26.4 ± 15.5 pg/ml (reference range 23–139, follicular phase, TSH 1.78 ± 0.86 mU/L (reference range 0.3–4.2 and PRL 409.4 ± 356 mU/L (reference range 70.8–556 (mean ± SD.Serum estradiol, TSH and PRL averaged 47.2 ± 27 pg/ml, 0.77 ± 0.48 mU/L and 246.4 ± 206.8 mU/L just prior to the buserelin injection, but they peaked at 253.4 ± 113.5 pg/ml (nv 83–495, midcycle, 3.30 ± 1.65 mU/L and 540.3 ± 695.2 mU/L after injection. The responses to buserelin of estradiol, TSH and PRL were of wide magnitude. There was a significant correlation between TSH peak and serum estradiol peak, betweeen AUC0-24 h-TSH and AUC0-24 h-estradiol, or between PRL peak and estradiol peak and AUC0-24 h -PRL and AUC0-24 h-estradiol in only a subgroup of women.Therefore, women

  20. Syntheses, structural elucidation, thermal properties, theoretical quantum chemical studies (DFT and biological studies of barbituric–hydrazone complexes

    Directory of Open Access Journals (Sweden)

    Amina A. Soayed

    2015-03-01

    Full Text Available Condensation of barbituric acid with hydrazine hydrate yielded barbiturichydrazone (L which was characterized using IR, 1H NMR and mass spectra. The Co(II, Ni(II and Cu(II complexes derived from this ligand have been synthesized and structurally characterized by elemental analyses, spectroscopic methods (IR, UV–Vis and ESR and thermal analyses (TGA, DTG and DTA and the structures were further elucidated using quantum chemical density functional theory. Complexes of L were found to have the ML.nH2O stoichiometry with either tetrahedral or octahedral geometry. The ESR data showed the Cu(II complex to be in a tetragonal geometry. Theoretical investigation of the electronic structure of metal complexes at the TD-DFT/B3LYP level of theory has been carried out and discussed. The fundamental vibrational wavenumbers were calculated and a good agreement between observed and scaled calculated wavenumbers was achieved. Thermal studies were performed to deduce the stabilities of the ligand and complexes. Thermodynamic parameters, such as the order of reactions (n, activation energy ΔE∗, enthalpy of reaction ΔH∗ and entropy ΔS∗ were calculated from DTA curves using Horowitz–Metzger method. The ligand L and its complexes have been screened for their antifungal and antibacterial activities and were found to possess better biological activities compared to those of unsubstituted barbituric acid complexes.

  1. Structural elucidation of the hormonal inhibition mechanism of the bile acid cholate on human carbonic anhydrase II

    International Nuclear Information System (INIS)

    Boone, Christopher D.; Tu, Chingkuang; McKenna, Robert

    2014-01-01

    The structure of human carbonic anhydrase II in complex with cholate has been determined to 1.54 Å resolution. Elucidation of the novel inhibition mechanism of cholate will aid in the development of a nonsulfur-containing, isoform-specific therapeutic agent. The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO 2 into bicarbonate and a proton. Human isoform CA II (HCA II) is abundant in the surface epithelial cells of the gastric mucosa, where it serves an important role in cytoprotection through bicarbonate secretion. Physiological inhibition of HCA II via the bile acids contributes to mucosal injury in ulcerogenic conditions. This study details the weak biophysical interactions associated with the binding of a primary bile acid, cholate, to HCA II. The X-ray crystallographic structure determined to 1.54 Å resolution revealed that cholate does not make any direct hydrogen-bond interactions with HCA II, but instead reconfigures the well ordered water network within the active site to promote indirect binding to the enzyme. Structural knowledge of the binding interactions of this nonsulfur-containing inhibitor with HCA II could provide the template design for high-affinity, isoform-specific therapeutic agents for a variety of diseases/pathological states, including cancer, glaucoma, epilepsy and osteoporosis

  2. Structural elucidation of the hormonal inhibition mechanism of the bile acid cholate on human carbonic anhydrase II

    Energy Technology Data Exchange (ETDEWEB)

    Boone, Christopher D. [University of Florida, PO Box 100267, Gainesville, FL 32610 (United States); Tu, Chingkuang [University of Florida, PO Box 100245, Gainesville, FL 32610 (United States); McKenna, Robert, E-mail: rmckenna@ufl.edu [University of Florida, PO Box 100267, Gainesville, FL 32610 (United States)

    2014-06-01

    The structure of human carbonic anhydrase II in complex with cholate has been determined to 1.54 Å resolution. Elucidation of the novel inhibition mechanism of cholate will aid in the development of a nonsulfur-containing, isoform-specific therapeutic agent. The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO{sub 2} into bicarbonate and a proton. Human isoform CA II (HCA II) is abundant in the surface epithelial cells of the gastric mucosa, where it serves an important role in cytoprotection through bicarbonate secretion. Physiological inhibition of HCA II via the bile acids contributes to mucosal injury in ulcerogenic conditions. This study details the weak biophysical interactions associated with the binding of a primary bile acid, cholate, to HCA II. The X-ray crystallographic structure determined to 1.54 Å resolution revealed that cholate does not make any direct hydrogen-bond interactions with HCA II, but instead reconfigures the well ordered water network within the active site to promote indirect binding to the enzyme. Structural knowledge of the binding interactions of this nonsulfur-containing inhibitor with HCA II could provide the template design for high-affinity, isoform-specific therapeutic agents for a variety of diseases/pathological states, including cancer, glaucoma, epilepsy and osteoporosis.

  3. Mass spectrometry for the elucidation of the subtle molecular structure of biodegradable polymers and their degradation products.

    Science.gov (United States)

    Kowalczuk, Marek; Adamus, Grażyna

    2016-01-01

    Contemporary reports by Polish authors on the application of mass spectrometric methods for the elucidation of the subtle molecular structure of biodegradable polymers and their degradation products will be presented. Special emphasis will be given to natural aliphatic (co)polyesters (PHA) and their synthetic analogues, formed through anionic ring-opening polymerization (ROP) of β-substituted β-lactones. Moreover, the application of MS techniques for the evaluation of the structure of biodegradable polymers obtained in ionic and coordination polymerization of cyclic ethers and esters as well as products of step-growth polymerization, in which bifunctional or multifunctional monomers react to form oligomers and eventually long chain polymers, will be discussed. Furthermore, the application of modern MS techniques for the assessment of polymer degradation products, frequently bearing characteristic end groups that can be revealed and differentiated by MS, will be discussed within the context of specific degradation pathways. Finally, recent Polish accomplishments in the area of mass spectrometry will be outlined. © 2015 Wiley Periodicals, Inc.

  4. Structure elucidation and toxicity analyses of the radiolytic products of aflatoxin B{sub 1} in methanol-water solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Graduate School of Chinese Academy of Agricultural Sciences, 12th Zhongguancun South Road, Hai Dian District, Beijing 100081 (China); Xie, Fang [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Xue, Xiaofeng [Bee Research Institute of Chinese Academy of Agricultural Sciences, 1st Xiangshan North Ditch, Hai Dian District, Beijing 100093 (China); Wang, Zhidong; Fan, Bei [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Ha, Yiming, E-mail: wxfay2011@hotmail.com [Institute of Agro-food Science and Technology of Chinese Academy of Agricultural Sciences, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China); Key Opening Laboratory of Agricultural Products Processing and Quality Control, Ministry of Agriculture, 2nd Yuanmingyuan West Road, Hai Dian District, Beijing 100193 (China)

    2011-09-15

    Highlights: {yields} Radiolytic products of aflatoxin B{sub 1} were produced under gamma irradiation. {yields} Seven key radiolytic products were structure-elucidated. {yields} Free-radical species in radiolytic solution resulted in the formation of products. {yields} Based on the structure-activity relationship analysis, the toxicity of radiolytic products was significantly reduced compared with that of AFB{sub 1}. {yields} The addition reaction on furan ring double bond was the reason for the reduced toxicity. - Abstract: The identification of the radiolytic products of mycotoxins is a key issue in the feasibility study of gamma ray radiation detoxification. Methanol-water solution (60:40, v/v) spiked with aflatoxin B{sub 1} (AFB{sub 1}; 20 mg L{sup -1}) was irradiated with Co{sup 60} gamma ray to generate radiolytic products. Liquid chromatography-quadruple time-of-flight mass spectrometry was applied to identify the radiolytic products of AFB{sub 1}. Accurate mass and proposed molecular formulas with a high-matching property of more than 20 radiolytic products were obtained. Seven key radiolytic products were proposed based on the molecular formulas and tandem mass spectrometry spectra. The analyses of toxicity and formation pathways were proposed based on the structure of the radiolytic products. The addition reaction caused by the free-radical species in the methanol-water solution resulted in the formation of most radiolytic products. Based on the structure-activity relationship analysis, the toxicity of radiolytic products was significantly reduced compared with that of AFB{sub 1} because of the addition reaction that occurred on the double bond in the terminal furan ring. For this reason, gamma irradiation is deemed an effective tool for the detoxification of AFB{sub 1}.

  5. Serum Levels of Thyroid Hormones and Thyrotropin in Some Sickle ...

    African Journals Online (AJOL)

    The serum levels of the thyroid hormones (T4 and T3) and thyrotropin (TSH) were measured by radio-immunoassay (RIA) in the steady state of 10 homozygous sickle cell anaemia patients and 10 normal subjects of the same age group in years (15-25) who were the control group. The results showed that sickle cell disease ...

  6. Preparation of standards of triiodothyronine, thyroxine and thyrotropin

    International Nuclear Information System (INIS)

    Lavalley E, C.; Delgado S, B.; Ruiz J, A.; Zambrano A, F.

    1991-10-01

    The standards preparation requires of certain basic principles, some of which are described in this work, which was made with the purpose of establishing the most appropriate conditions for the preparation of standards of triiodothyronine, thyroxine and thyrotropin to be used in radioimmunoanalysis essays. The diverse standards show a balanced displacement, that which is observed in the graphs presented in this work. (Author)

  7. Purification and partial elucidation of the structure of an antioxidant carbohydrate biopolymer from the probiotic bacterium Bacillus coagulans RK-02.

    Science.gov (United States)

    Kodali, Vidya P; Perali, Ramu S; Sen, R

    2011-08-26

    An exopolysaccharide (EPS) was isolated from Bacillus coagulans RK-02 and purified by size exclusion chromatography. The purified, homogeneous EPS had an average molecular weight of ∼3 × 10⁴ Da by comparison with FITC-labeled dextran standards. In vivo evaluations showed that, like other reported polysaccharides, this EPS displayed significant antioxidant activity. FTIR spectroscopy analysis showed the presence of hydroxy, carboxy, and α-glycosidic linkages and a mannose residue. GC analysis indicated that the EPS was a heteropolymer composed of glucose, mannose, galactose, glucosamine, and fucose as monomeric constituent units. Partial elucidation of the structure of the carbohydrate biopolymer based on GC-MS and NMR analysis showed the presence of two unique sets of tetrasaccharide repeating units that have 1→3 and 1→6 glycosidic linkages. This is also the first report of a Gram-positive bacterial polysaccharide with both fucose as a sugar monomer and 1→3 and 1→6 glycosidic linkages in the molecular backbone.

  8. A comparative study of the DG-OMEGA (DG Omega), DGII, and GAT method for the structure elucidation of a methylene-acetal linked thymine dinucleotide

    NARCIS (Netherlands)

    van Kampen, A. H. C.; Beckers, M. L. M.; Buydens, L. M. C.

    1997-01-01

    This research continues the investigation of the properties of the recently developed structure elucidation method DG-OMEGA (DG Omega). Towards this end it was applied for the structure determination of a methylene-acetal linked thymine dinucleotide. The performance of DG Omega was compared to the

  9. Mutations that silence constitutive signaling activity in the allosteric ligand-binding site of the thyrotropin receptor.

    Science.gov (United States)

    Haas, Ann-Karin; Kleinau, Gunnar; Hoyer, Inna; Neumann, Susanne; Furkert, Jens; Rutz, Claudia; Schülein, Ralf; Gershengorn, Marvin C; Krause, Gerd

    2011-01-01

    The thyrotropin receptor (TSHR) exhibits elevated cAMP signaling in the basal state and becomes fully activated by thyrotropin. Previously we presented evidence that small-molecule ligands act allosterically within the transmembrane region in contrast to the orthosteric extracellular hormone-binding sites. Our goal in this study was to identify positions that surround the allosteric pocket and that are sensitive for inactivation of TSHR. Homology modeling combined with site-directed mutagenesis and functional characterization revealed seven mutants located in the allosteric binding site that led to a decrease of basal cAMP signaling activity. The majority of these silencing mutations, which constrain the TSHR in an inactive conformation, are found in two clusters when mapped onto the 3D structural model. We suggest that the amino acid positions identified herein are indicating locations where small-molecule antagonists, both neutral antagonists and inverse agonists, might interfere with active TSHR conformations.

  10. Structure elucidation and in vitro cytotoxicity of ochratoxin α amide, a new degradation product of ochratoxin A.

    Science.gov (United States)

    Bittner, Andrea; Cramer, Benedikt; Harrer, Henning; Humpf, Hans-Ulrich

    2015-05-01

    The mycotoxin ochratoxin A is a secondary metabolite occurring in a wide range of commodities. During the exposure of ochratoxin A to white and blue light, a cleavage between the carbon atom C-14 and the nitrogen atom was described. As a reaction product, the new compound ochratoxin α amide has been proposed based on mass spectrometry (MS) experiments. In the following study, we observed that this compound is also formed at high temperatures such as used for example during coffee roasting and therefore represents a further thermal ochratoxin A degradation product. To confirm the structure of ochratoxin α amide, the compound was prepared in large scale and complete structure elucidation via nuclear magnetic resonance (NMR) and MS was performed. Additionally, first studies on the toxicity of ochratoxin α amide were performed using immortalized human kidney epithelial (IHKE) cells, a cell line known to be sensitive against ochratoxin A with an IC50 value of 0.5 μM. Using this system, ochratoxin α amide revealed no cytotoxicity up to concentrations of 50 μM. Thus, these results propose that the thermal degradation of ochratoxin A to ochratoxin α amide might be a detoxification process. Finally, we present a sample preparation and a HPLC-tandem mass spectrometry (HPLC-MS/MS) method for the analysis of ochratoxin α amide in extrudates and checked its formation during the extrusion of artificially contaminated wheat grits at 150 and 180 °C, whereas no ochratoxin α amide was detectable under these conditions.

  11. Structure elucidation, protein profile and the antitumor effect of the biological active substance extracted from sea cucumber Holothuria polii.

    Science.gov (United States)

    Omran, Nahla Ee; Khedr, Abdalla M

    2015-01-01

    Holothuria polii (Delle Chiaje, 1823) (Holothuriidae) is a sea cucumber inhabiting Mediterranean Sea coast of Egypt. The bioactive compound of its tegument has antifungal, antibacterial and antiparasitic effects. The present study aims to elucidate the structure of the bioactive material of H. polii for pharmacological and chemotaxonomic purposes. Furthermore, the study demonstrates its efficacy as a cytotoxic agents against two tumor cell lines HCT116 (colon adenocarcinoma cell line) and MCF7 (breast adenocarcinoma cell line). The biological active compound of the ethanol extract has been characterized by means of infrared (IR), proton-nuclear magnetic resonance ((1)H NMR), ultraviolet-visible (UV-Vis) and mass spectra. Protein profile was carried out using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Cytotoxic activity was carried out according to sulforhodamine-B assay. IR, (1)H NMR, UV-Vis and mass spectra showed that the extracted bioactive material is a nonsulfated hexaosides called bivittoside. This glycoside is composed of aglycone and a glycosidic chain (carbohydrate chain) enclosed with six sugar units, including xylose, glucose, 3-O-methylglucose and quinovose. There were no traces of dissolved proteins. The preliminary cytotoxic assay of bivittoside exhibited significant cytotoxic activity against two types of cultured tumor cell lines of HCT116 and MCF7. The half-maximal inhibitory concentration was 17.4 µg/ml and 18 µg/ml for MCF7 and HCT116, respectively. Although H. polii belongs to the genus Holothuria, the lacking of sulfate group and the fact that it contains up to six monosaccharides make it different from this genus. The present study suggests separation of H. polii from its genus to a new one. On the other hand, results support the hypothesis that H. polii bioactive compound has an antitumor effect. © The Author(s) 2012.

  12. Structural elucidation of biologically active neomycin N-octyl derivatives in a regioisomeric mixture by means of liquid chromatography/ion trap time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Giera, M.; de Vlieger, J.S.B.; Lingeman, H.; Irth, H.; Niessen, W.M.A.

    2010-01-01

    Structural elucidation of six regioisomers of mono-N-octyl derivatized neomycin is achieved using MSn (up to n1/4 4) on an ion trap time-of-flight (IT-TOF) instrument equipped with electrospray ionization. The mixture of six derivatized neomycin analogues was generated by reductive amination in a

  13. Structure Elucidation of A New Coumarin Type Compound, Alternamin, Isolated from the Plant (Murraya Alternans (Kurz) Swingle) Having The Antidote Activity on Snake Venoms

    International Nuclear Information System (INIS)

    Hla Myo Min; Mya Aye

    2004-06-01

    The structure of a new coumarin type compound isolated from the entitled species was elucidated by the full spectral analysis consisting of FTIR, 1H NMR, DQF COSY, 13C NMR, DEPT, EIMS (HR-EIMS), HMQC and HMBC. The antidote activities of the fresh juice and the ethanolic extract of the plant, and the isolated compound alternamin were also determined

  14. Chemistry of renieramycins. Part 5. Structure elucidation of renieramycin-type derivatives O, Q, R, and S from thai marine sponge Xestospongia species pretreated with potassium cyanide.

    Science.gov (United States)

    Amnuoypol, Surattana; Suwanborirux, Khanit; Pummangura, Sunibhond; Kubo, Akinori; Tanaka, Chieko; Saito, Naoki

    2004-06-01

    Four minor renieramycin-type derivatives, including renieramycins O (1o) and Q-S (1q-s), were isolated from the sponge Xestospongia sp. pretreated with potassium cyanide. Their structures were elucidated by comparison of spectral data with those of recently reported renieramycins M (1m) and N (1n). The results of transformation and cytotoxicity measurements are also described.

  15. Elucidation of the mode of interaction of thermolysin with a proteinaceous metalloproteinase inhibitor, SMPI, based on a model complex structure and a structural dynamics analysis.

    Science.gov (United States)

    Tate, S; Ohno, A; Seeram, S S; Hiraga, K; Oda, K; Kainosho, M

    1998-09-18

    SMPI is a proteinaceous microbial metalloproteinase inhibitor that was isolated from Streptomyces nigrescens TK-23 in 1979. SMPI is known to selectively inhibit the metalloproteinases in the gluzincin family, according to the Rawling and Barrett classification. There has been no report on the interaction of a metalloproteinase in the family of gluzincins with its specific proteinaceous inhibitor. We have solved the solution structure of SMPI by NMR. Here, we report the binding mode of SMPI to thermolysin, based on the model complex structure generated using our high-resolution NMR structure of SMPI and the crystal structure of thermolysin. The obtained complex model shows that the extruded loop of SMPI, with the scissile bond Cys64-Val65, is complementary in shape to the active cleft of thermolysin. In the complex, the Cys64 (P1) carbonyl oxygen atom can form a tetrahedral coordination to the active zinc in thermolysin, and simultaneously, the methyl groups of Val65 (P1') are closely located in the hydrophobic S1' pocket in thermolysin. From the electrostatic potential surface calculation, the active loop of SMPI and the active cleft in thermolysin have been shown to be complementary in the surface charge distribution, resulting in the stabilization of the complex. The apparently large active loop is less flexible, but maintains a conformation in the nano- to picosecond time-scale, as elucidated from the 15N spin relaxation analysis. This is a quite different structural feature of SMPI from the flexible binding loop generally found in the serine proteinase inhibitors, such as SSI and eglin c, and can be related to the narrow specificity of SMPI. The present study provides the first insight into the interaction between a proteinaceous inhibitor and a gluzincin metalloproteinase. Copyright 1998 Academic Press.

  16. Pathogenetic Role of Thyrotropin Receptor Antibody in the Development of Hyperthyroidism Following Primary Hypothyroidism *

    OpenAIRE

    Shong, Young Kee; Cho, Bo Youn; Hong, Sung Kwan; Lee, Hong Kyu; Koh, Chang-Soon; Min, Hun Ki

    1989-01-01

    The authors measured thyrotropin binding inhibitory immunoglobulin (TBII), thyroid stimulating antibody (TSAb), and thyroid stimulation blocking antibody (TSBAb) sequentially in patients who developed hyperthyroidism following primary hypothyroidism, and compared changes in these various funcional parameters of thyrotropin receptor antibody (TRAb) with clinical manifestations, in order to investigate the role of TRAb in the development of hyperthyroidism following primary hypothyroidism. In a...

  17. LC-MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products

    Energy Technology Data Exchange (ETDEWEB)

    Slegers, Catherine [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium)]. E-mail: catherine.slegers@skynet.be; Maquille, Aubert [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium); Deridder, Veronique [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium); Sonveaux, Etienne [Unite de Chimie Pharmaceutique et de Radiopharmacie, Universite Catholique de Louvain, Brussels (Belgium); Habib Jiwan, Jean-Louis [Laboratoire de Spectrometrie de Masse, Universite Catholique de Louvain, Louvain-La-Neuve (Belgium); Tilquin, Bernard [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium)

    2006-09-15

    E-beam and gamma products from the radiolysis of aqueous solutions of ({+-})-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of ({+-})-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

  18. Levothyroxine sodium revisited: A wholistic structural elucidation approach of new impurities via HPLC-HRMS/MS, on-line H/D exchange, NMR spectroscopy and chemical synthesis.

    Science.gov (United States)

    Ruggenthaler, M; Grass, J; Schuh, W; Huber, C G; Reischl, R J

    2017-02-20

    The structural elucidation of unknown pharmaceutical impurities plays an important role in the quality control of newly developed and well-established active pharmaceutical ingredients (APIs). The United States Pharmacopeia (USP) monograph for the API Levothyroxine Sodium, a synthetic thyroid hormone, features two high pressure liquid chromatography (HPLC) methods using UV-VIS absorption detection to determine organic impurities in the drug substance. The impurity profile of the first USP method ("Procedure 1") has already been extensively studied, however for the second method ("Procedure 2"), which exhibits a significantly different impurity profile, no wholistic structural elucidation of impurities has been performed yet. Applying minor modifications to the chromatographic parameters of USP "Procedure 2" and using various comprehensive structural elucidation methods such as high resolution tandem mass spectrometry with on-line hydrogen-deuterium (H/D) exchange or two-dimensional nuclear magnetic resonance spectroscopy (NMR) we gained new insights about the complex impurity profile of the synthetic thyroid hormone. This resulted in the characterization of 24 compounds previously unknown to literature and the introduction of two new classes of Levothyroxine Sodium impurities. Five novel compounds were unambiguously identified via isolation or synthesis of reference substances and subsequent NMR spectroscopic investigation. Additionally, Collision-Induced Dissociation (CID)-type fragmentation of identified major impurities as well as neutral loss fragmentation patterns of many characterized impurities were discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Application of recombinant human thyrotropin and redifferentiation drugs in differentiated thyroid cancer

    International Nuclear Information System (INIS)

    Meng Zhaowei; Tan Jian

    2006-01-01

    In the management of differentiated thyroid cancer, radioiodine ( 131 I) ablation of thyroid remnants and 131 I treatment of metastatic lesions are very important. To prepare for ablation or treatment, optimal level of TSH has to be achieved. Recombinant human thyrotropin (rhTSH) has the same structure and biological activity as endogenous TSH. It can effectively elevate serum TSH level and it has little side effects. rhTSH can also avoid hypothyroid symptoms which are sometimes very serious if withdrawal of thyroid hormone therapy is carried out. However, in a number of cases, dedifferentiation is observed, giving rise to poor prognostic thyroid cancers that are refractory to conventional treatment. Several novel approaches for the treatment of dedifferentiated thyroid cancers have made great breakthroughs. For instance, isotretinoin redifferentiation therapy has entered Phase II clinical trials. (authors)

  20. The potential utility of predicted one bond carbon-proton coupling constants in the structure elucidation of small organic molecules by NMR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Venkata

    Full Text Available NMR spectroscopy is the most popular technique used for structure elucidation of small organic molecules in solution, but incorrect structures are regularly reported. One-bond proton-carbon J-couplings provide additional information about chemical structure because they are determined by different features of molecular structure than are proton and carbon chemical shifts. However, these couplings are not routinely used to validate proposed structures because few software tools exist to predict them. This study assesses the accuracy of Density Functional Theory for predicting them using 396 published experimental observations from a diverse range of small organic molecules. With the B3LYP functional and the TZVP basis set, Density Functional Theory calculations using the open-source software package NWChem can predict one-bond CH J-couplings with good accuracy for most classes of small organic molecule. The root-mean-square deviation after correction is 1.5 Hz for most sp3 CH pairs and 1.9 Hz for sp2 pairs; larger errors are observed for sp3 pairs with multiple electronegative substituents and for sp pairs. These results suggest that prediction of one-bond CH J-couplings by Density Functional Theory is sufficiently accurate for structure validation. This will be of particular use in strained ring systems and heterocycles which have characteristic couplings and which pose challenges for structure elucidation.

  1. Elucidating the multiple genetic lineages and population genetic structure of the brooding coral Seriatopora (Scleractinia: Pocilloporidae) in the Ryukyu Archipelago

    Science.gov (United States)

    Nakajima, Yuichi; Nishikawa, Akira; Iguchi, Akira; Nagata, Tomofumi; Uyeno, Daisuke; Sakai, Kazuhiko; Mitarai, Satoshi

    2017-06-01

    The elucidation of species diversity and connectivity is essential for conserving coral reef communities and for understanding the characteristics of coral populations. To assess the species diversity, intraspecific genetic diversity, and genetic differentiation among populations of the brooding coral Seriatopora spp., we conducted phylogenetic and population genetic analyses using a mitochondrial DNA control region and microsatellites at ten sites in the Ryukyu Archipelago, Japan. At least three genetic lineages of Seriatopora (Seriatopora-A, -B, and -C) were detected in our specimens. We collected colonies morphologically similar to Seriatopora hystrix, but these may have included multiple, genetically distinct species. Although sexual reproduction maintains the populations of all the genetic lineages, Seriatopora-A and Seriatopora-C had lower genetic diversity than Seriatopora-B. We detected significant genetic differentiation in Seriatopora-B among the three populations as follows: pairwise F ST = 0.064-0.116 (all P = 0.001), pairwise G''ST = 0.107-0.209 (all P = 0.001). Additionally, only one migrant from an unsampled population was genetically identified within Seriatopora-B. Because the peak of the settlement of Seriatopora larvae is within 1 d and almost all larvae are settled within 5 d of spawning, our observations may be related to low dispersal ability. Populations of Seriatopora in the Ryukyu Archipelago will probably not recover unless there is substantial new recruitment from distant populations.

  2. Thyrotropin-luteinizing hormone/chorionic gonadotropin receptor extracellular domain chimeras as probes for thyrotropin receptor function

    International Nuclear Information System (INIS)

    Nagayama, Yuji; Wadsworth, H.L.; Chazenbalk, G.D.; Russo, D.; Seto, Pui; Rapoport, B.

    1991-01-01

    To define the sites in the extracellular domain of the human thyrotropin (TSH) receptor that are involved in TSH binding and signal transduction the authors constructed chimeric thyrotropin-luteinizing hormone/chorionic gonadotropin (TSH-LH/CG) receptors. The extracellular domain of the human TSH receptor was divided into five regions that were replaced, either singly or in various combinations, with homologous regions of the rat LH/CG receptor. The chimeric receptors were stably expressed in Chinese hamster ovary cells. The data obtained suggest that the carboxyl region of the extracellular domain (amino acid residues 261-418) and particularly the middle region (residues 171-260) play a role in signal transduction. The possibility is also raised of an interaction between the amino and carboxyl regions of the extracellular domain in the process of signal transduction. In summary, these studies suggest that the middle region and carboxyl half of the extracellular domain of the TSH receptor are involved in signal transduction and that the TSH-binding region is likely to span the entire extracellular domain, with multiple discontinuous contact sites

  3. High-performance liquid chromatography on-line coupled to high-field NMR and mass spectrometry for structure elucidation of constituents of Hypericum perforatum L

    DEFF Research Database (Denmark)

    Hansen, S. H.; Jensen, A. G.; Cornett, Claus

    1999-01-01

    (MS) is described. A conventional reversed-phase HPLC system using ammonium acetate as the buffer substance in the eluent tvas used, and proton NMR spectra were obtained on a 500 MHz NMR instrument. The MS and MS/MS analyses were performed using negative electrospray ionization, In the present study......The on-line separation and structure elucidation of naphthodianthrones, flavonoids, and other constituents of an extract from Hypericum perforatum L, using high performance liquid chromatography (HPLC) coupled on-line with ultraviolet-visible, nuclear magnetic resonance (NMR), and mass spectrometry...

  4. Structural Elucidation of Z- and E- Isomers of 5-Alkyl-4-ethoxycarbonyl-5-(4`-chlorophenyl-3-oxa-4-pentenoic Acids

    Directory of Open Access Journals (Sweden)

    H. M. F. Madkour

    2000-05-01

    Full Text Available Z- and E-isomers of 5-alkyl-4-ethoxycarbonyl-5-(4`-chlorophenyl-3-oxa-4-pentenoic acids were prepared via the condensation of p-chloroacetophenone and/or pchloropropiophenone with diethyl-2,2`-oxydiacetate in the presence of sodium hydride as a basic catalyst. The Z-isomers of 2a and 2b were found to be predominant. The behaviour of the corresponding anhydrides towards the action of hydrazine, phenylhydrazine, primary aromatic amines, hydrocarbons and ethanolysis has also been investigated. The structures and configurations of the products have been elucidated by chemical and spectroscopic means.

  5. Effect of primary particle size on spray formation, morphology and internal structure of alumina granules and elucidation of flowability and compaction behaviour

    Directory of Open Access Journals (Sweden)

    Pandu Ramavath

    2014-06-01

    Full Text Available Three different alumina powders with varying particle sizes were subjected to spray drying under identical conditions and effect of particle size on heat transfer efficiency and mechanism of formation of granules was elucidated. Morphology, internal structure and size distribution of granules were studied and evaluated with respect to their flow behaviour. In order to estimate the elastic interaction of granules, the granules were subjected to compaction under progressive loading followed by periodic unloading. Compaction curves were plotted and compressibility factor was estimated and correlated with predicted and measured green density values.

  6. Constitutive Relations Analyses of Plastic Flow in Dual-Phase Steels to Elucidate Structure-Strength-Ductility Correlations

    Science.gov (United States)

    Saimoto, S.; Timokhina, I. B.; Pereloma, E. V.

    2017-07-01

    The structure-strength characterization is typically performed by correlating the structure with x-ray, electron, or atomic imaging devices to the bulk mechanical tensile parameters of yield stress and the plastic yielding response. The problem is that structure parameters embedded in the stress-strain data cannot be revealed without an analyzable constitutive relation. New functional slip-based constitutive formulation with precise digital fitting parameters can replicate the measured data with at least two loci. Thus, this study examines the possibility of identifying the mechanical response as a result of the various microstructure components. The key parameter, the mean slip distance, can be calibrated from the initial work-hardening slope at 0.2% strain from which all the fit parameters can be determined. In this process, a newly derived friction stress is defined to separate the yield phenomenon from the plastic strains beyond yield-point elongation. This methodology has been applied to dual-phase steel specimens that resulted in excellent predictive correlations with prior structure-strength characterization. Hence, the structure-strength-ductility changes resulting from processing conditions can be more precisely surmised from mechanical testing. Thus, a method to delineate the nanostructure evolution with deformation using mesoscopic mechanical parameters has been introduced.

  7. Structural elucidation of a novel core oligosaccharide backbone of the lipopolysaccharide from the new bacterial species Agrobacterium larrymoorei.

    Science.gov (United States)

    Molinaro, Antonio; De Castro, Cristina; Lanzetta, Rosa; Parrilli, Michelangelo; Raio, Aida; Zoina, Astolfo

    2003-11-14

    Agrobacterium larrymoorei is a Gram-negative phytopathogenic bacterium, which produces tumours on Ficus benjamina plants and differs from other Agrobacteria both genetically and biochemically. The lipopolysaccharide (LPS) plays an important role in the pathogenesis of Agrobacteria. The present paper is the first report on the molecular primary structure of the core region of an Agrobacterium LPS. The following structure of the core and lipid A carbohydrate backbone of an R-form LPS of A. larrymoorei was determined by chemical degradations and 1D and 2D NMR spectroscopy: [carbohydrate structure: see text] All sugars are alpha-D-pyranoses if not stated otherwise, Kdo is 3-deoxy-D-manno-oct-2-ulosonic acid, Qui3NAcyl is 3,6-dideoxy-3-(3-hydroxy-2,3-dimethyl-5-oxoprolylamino)glucose, GlcAN and GalAN are amides of GlcA and GalA.

  8. Structural Elucidation of the DFG-Asp in and DFG-Asp out States of TAM Kinases and Insight into the Selectivity of Their Inhibitors

    Directory of Open Access Journals (Sweden)

    Abdellah Messoussi

    2014-10-01

    Full Text Available Structural elucidation of the active (DFG-Asp in and inactive (DFG-Asp out states of the TAM family of receptor tyrosine kinases is required for future development of TAM inhibitors as drugs. Herein we report a computational study on each of the three TAM members Tyro-3, Axl and Mer. DFG-Asp in and DFG-Asp out homology models of each one were built based on the X-ray structure of c-Met kinase, an enzyme with a closely related sequence. Structural validation and in silico screening enabled identification of critical amino acids for ligand binding within the active site of each DFG-Asp in and DFG-Asp out model. The position and nature of amino acids that differ among Tyro-3, Axl and Mer, and the potential role of these residues in the design of selective TAM ligands, are discussed.

  9. Elucidation of the structure of organic solutions in solvent extraction by combining molecular dynamics and X-ray scattering

    International Nuclear Information System (INIS)

    Ferru, G.; Gomes Rodrigues, D.; Berthon, L.; Guilbaud, P.; Diat, O.; Bauduin, P.

    2014-01-01

    Knowledge of the supramolecular structure of the organic phase containing amphiphilic ligand molecules is mandatory for full comprehension of ionic separation during solvent extraction. Existing structural models are based on simple geometric aggregates, but no consensus exists on the interaction potentials. Herein, we show that molecular dynamics crossed with scattering techniques offers key insight into the complex fluid involving weak interactions without any long range ordering. Two systems containing mono- or diamide extractants in heptane and contacted with an aqueous phase were selected as examples to demonstrate the advantages of coupling the two approaches for furthering fundamental studies on solvent extraction. (authors)

  10. Elucidation of Structural Elements for Selectivity across Monoamine Transporters: Novel 2-[(Diphenylmethyl)sulfinyl]acetamide (Modafinil) Analogues

    DEFF Research Database (Denmark)

    Okunola-Bakara, Oluyomi; Cao, Jianjing; Kopajtic, Theresa

    2014-01-01

    2-[(Diphenylmethyl)sulfinyl]acetamide (modafinil, (±)-1) is a unique dopamine uptake inhibitor that binds the dopamine transporter (DAT) differently than cocaine and may have potential for the treatment of psychostimulant abuse. To further investigate structural requirements for this divergent...

  11. Insights into structural features of HDAC1 and its selectivity inhibition elucidated by Molecular dynamic simulation and Molecular Docking.

    Science.gov (United States)

    Sixto-López, Yudibeth; Bello, Martiniano; Correa-Basurto, José

    2018-03-06

    Histone deacetylases (HDACs) are a family of proteins whose main function is the removal of acetyl groups from lysine residues located on histone and non-histone substrates, which regulates gene transcription and other activities in cells. HDAC1 dysfunction has been implicated in cancer development and progression; thus, its inhibition has emerged as a new therapeutic strategy. Two additional metal binding sites (Site 1 and Site 2) in HDACs have been described that are primarily occupied by potassium ions, suggesting a possible structural role that affects HDAC activity. In this work, we explored the structural role of potassium ions in Site 1 and Site 2 and how they affect the interactions of compounds with high affinities for HDAC1 (AC1OCG0B, Chlamydocin, Dacinostat and Quisinostat) and SAHA (a pan-inhibitor) using molecular docking and molecular dynamics (MD) simulations in concert with a Molecular-Mechanics-Generalized-Born-Surface-Area (MMGBSA) approach. Four models were generated: one with a potassium ion (K + ) in both sites (HDAC1 k ), a second with K + only at site 1 (HDAC1 ks1 ), a third with K + only at site 2 (HDAC1 ks2 ) and a fourth with no K + (HDAC1 wk ). We found that the presence or absence of K + not only impacted the structural flexibility of HDAC1, but also its molecular recognition, consistent with experimental findings. These results could therefore be useful for further structure-based drug design studies addressing new HDAC1 inhibitors.

  12. Elucidation of Chemical Structure of Wood Lignin by Dissolving in 1-Butyl-3-methylimidazolium Chloride Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Ali Abdulkhani

    2012-12-01

    Full Text Available Residual lignin of wood after MWL isolation was dissolved with 1-butyl-3-methylimidazolium chloride ionic liquid. Chemical structure of isolated MWL from poplar wood (Popolus deltiodes and dissolved residual lignin were characterized with gas chromatography and 1D, 2D NMR techniques. Analytical results showed that  Popolus deltoides wood has more 4-(3-hydroxy-1-propenyl-2-methoxy phenol units (Guayacil lignin than 4-(3-hydroxy-1-propenyl-2,6-dimethoxy phenol units (Syringyl moieties. In addition to Guayacil and Syringyl, the extracted ligin is composed of a small amount of p-benzyl alcohol. The residual lignin is mainly composed of condensed structures which are often of carbohydrate complexes. The lignin structural ratios of dissolved wood in ionic liquid are the same as those of dioxan extracted lignin. Anomeric HSQC analysis of lignin showed that the lignin carbohydrate complex is composed of cellulose, xylan, mannan and arabinan sugars. Side-chain region of lignin structure is mainly composed of β-O-4, phenylcoumaran, resinol and spirodienone moieties.

  13. Predictions of flavonoid solubility in ionic liquids by COSMO-RS: experimental verification, structural elucidation, and solvation characterization

    DEFF Research Database (Denmark)

    Guo, Zheng; Lue, Bena-Marie; Thomsen, Kaj

    2007-01-01

    Predictions of the solubility of flavonoids in a large variety of ionic liquids (ILs) with over 1800 available structures were examined based on COSMO-RS computation. The results show that the solubilities of flavonoids are strongly anion-dependent. Experimental measurement of the solubilities...... of esculin and rutin in 12 ILs with varying anions and cations show that predicted and experimental results generally have a good agreement. Based on the sound physical basis of COSMO-RS, the solubility changes of flavonoids were quantitatively associated with solvation interactions and structural...... characteristics of ILs. COSMO-RS derived parameters, i.e. misfit, H-bonding and van der Waals interaction energy, are shown to be capable of characterizing the complicated multiple interactions in the IL system effectively. H-bonding interaction is the most dominant interaction for ILs (followed by misfit and van...

  14. Porphyrins from Messel oil shale (Eocene, Germany): Structure elucidation, geochemical and biological significance, and distribution as a function of depth

    Science.gov (United States)

    Ocampo, Rubén; Bauder, Claude; Callot, Henry J.; Albrecht, Pierre

    1992-02-01

    The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3) and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical "Treibs scheme," including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d, homolog pairs of porphyrins (3-H/3-ethyl), etc.

  15. Metal interactions at the biochar-water interface: energetics and structure-sorption relationships elucidated by flow adsorption microcalorimetry.

    Science.gov (United States)

    Harvey, Omar R; Herbert, Bruce E; Rhue, Roy D; Kuo, Li-Jung

    2011-07-01

    Plant-derived biochars exhibit large physicochemical heterogeneity due to variations in biomass chemistry and combustion conditions. However, the influence of biochar heterogeneity on biochar-metal interaction mechanisms has not been systematically described. We used flow adsorption microcalorimetry to study structure-sorption relationships between twelve plant-derived biochars and two metals (K(+) and Cd(2+)) of different Lewis acidity. Irrespective of the biochar structure, sorption of K(+) (a hard Lewis acid) occurred predominantly on deprotonated functional groups via ion exchange with molar heats of adsorption (ΔH(ads)) of -4 kJ mol(-1) to -8 kJ mol(-1). By comparison, although ion exchange could not be completely ruled out, our data pointed to Cd(2+) (a soft Lewis acid) sorption occurring predominantly via two distinct cation-π bonding mechanisms, each with ΔH(ads) of +17 kJ mol(-1). The first, evident in low charge-low carbonized biochars, suggested Cd(2+)-π bonding to soft ligands such as -C ═ O; while the second, evident in low charge-highly carbonized biochars, pointed to Cd(2+)-π bonding with electron-rich domains on aromatic structures. Quantitative contributions of these mechanisms to Cd(2+) sorption can exceed 3 times that expected for ion exchange and therefore could have significant implications for the biogeochemical cycling of metals in fire-impacted or biochar-amended systems.

  16. Study on the Reactivity of Amino Acid Chemosensor, NPFNP, with Ethanol: Structural Elucidation through Single Crystal XRD and DFT Calculations

    Directory of Open Access Journals (Sweden)

    Beena Varghese

    2017-01-01

    Full Text Available A novel ethoxy derivative of an amino acid chemosensor, 3-naphthyl-1-phenyl-5-(2ʹ-fluoro-5ʹ-nitrophenyl-2-pyrazoline (NPFNP, has been synthesized and characterized by different spectroscopic methods.  A single crystal of the ethoxy derivative, 3-naphthyl-1-phenyl-5-(2ʹ-ethoxy-5ʹ-nitrophenyl-2-pyrazoline NPENP, has been obtained and characterized.  The structure holds interest as it carries biologically active pyrazoline as a central ring attaching to electron donating and withdrawing substituents. The major motivation for this work was to gain detailed insight into the structural parameters of this compound for investigating the influence of crystal packing and geometrical dimensions on optical properties. Time-dependent DFT calculations have been employed for comparing the XRD data with theoretical parameters. The results show that the DFT method at B3LYP/6-31G level can well reproduce the structure of the title compound.

  17. DIAGNOSTIC TOOLS FOR STRUCTURAL CHARACTERIZATION AND ELUCIDATION OF FIBRILS AND THEIR PRECURSORS IN AMYLOID FIBRIL FORMATION PATHWAY

    Directory of Open Access Journals (Sweden)

    Nidhi Kaur Bhatia

    2013-12-01

    Full Text Available The amyloid fibrils and their precursors are supposed to be responsible for several neurodegenerative diseases. Advances in recent experimental techniques rationalized our understanding on the mechanism of the amyloid fibril formation. The goal of this review is to revisit the various techniques used to diagnose the structural features of amyloid fibrils and their precursors, for a comprehensive view of the available tools, their advantages and disadvantages. The review will serve as a stepping stone for detailed understanding of each technique and its use as per specific requirements of a biological problem.

  18. Elucidating the native sources of an invasive tree species, Acacia pycnantha, reveals unexpected native range diversity and structure

    Science.gov (United States)

    Ndlovu, Joice; Richardson, David M.; Wilson, John R. U.; O'Leary, Martin; Le Roux, Johannes J.

    2013-01-01

    Background and Aims Understanding the introduction history of invasive plant species is important for their management and identifying effective host-specific biological control agents. However, uncertain taxonomy, intra- and interspecific hybridization, and cryptic speciation may obscure introduction histories, making it difficult to identify native regions to explore for host-specific agents. The overall aim of this study was to identify the native source populations of Acacia pycnantha, a tree native to south-eastern Australia and invasive in South Africa, Western Australia and Portugal. Using a phylogeographical approach also allowed an exploration of the historical processes that have shaped the genetic structure of A. pycnantha in its native range. Methods Nuclear (nDNA) and plastid DNA sequence data were used in network and tree-building analyses to reconstruct phylogeographical relationships between native and invasive A. pycnantha populations. In addition, mismatch distributions, relative rates and Bayesian analyses were used to infer recent demographic processes and timing of events in Australia that led to population structure and diversification. Key Results The plastid network indicated that Australian populations of A. pycnantha are geographically structured into two informally recognized lineages, the wetland and dryland forms, whereas the nuclear phylogeny showed little geographical structure between these two forms. Moreover, the dryland form of A. pycnantha showed close genetic similarity to the wetland form based on nDNA sequence data. Hybrid zones may explain these findings, supported here by incongruent phylogenetic placement of some of these taxa between nuclear and plastid genealogies. Conclusions It is hypothesized that habitat fragmentation due to cycles of aridity inter-dispersed with periods of abundant rainfall during the Pleistocene (approx. 100 kya) probably gave rise to native dryland and wetland forms of A. pycnantha. Although the

  19. Comparison of pituitary and recombinant human thyrotropin standards in an immunoradiometric system

    International Nuclear Information System (INIS)

    Blanca Fernandez, Silvia; Rodriguez Gonzalez, Julio Cesar; Nisembaum Alas, Amaparo; Sevy Gonzalez, O.

    1998-01-01

    Results of two standards of human thyrotropin of pituitaries (B) and recombinant (C) origen supplied by the Instituto of pesquisas Energeticas y Nucleares, Brazil, were compared in our immunoradiometric reference system that use an human thyrotropin pituitary standard of local production (A). This work was supported by the International Atomic Energy Agency for an inter-regional comparison and set up of a reference standard

  20. In situ analysis and structural elucidation of sainfoin (Onobrychis viciifolia) tannins for high-throughput germplasm screening.

    Science.gov (United States)

    Gea, An; Stringano, Elisabetta; Brown, Ron H; Mueller-Harvey, Irene

    2011-01-26

    A rapid thiolytic degradation and cleanup procedure was developed for analyzing tannins directly in chlorophyll-containing sainfoin ( Onobrychis viciifolia ) plants. The technique proved suitable for complex tannin mixtures containing catechin, epicatechin, gallocatechin, and epigallocatechin flavan-3-ol units. The reaction time was standardized at 60 min to minimize the loss of structural information as a result of epimerization and degradation of terminal flavan-3-ol units. The results were evaluated by separate analysis of extractable and unextractable tannins, which accounted for 63.6-113.7% of the in situ plant tannins. It is of note that 70% aqueous acetone extracted tannins with a lower mean degree of polymerization (mDP) than was found for tannins analyzed in situ. Extractable tannins had between 4 and 29 lower mDP values. The method was validated by comparing results from individual and mixed sample sets. The tannin composition of different sainfoin accessions covered a range of mDP values from 16 to 83, procyanidin/prodelphinidin (PC/PD) ratios from 19.2/80.8 to 45.6/54.4, and cis/trans ratios from 74.1/25.9 to 88.0/12.0. This is the first high-throughput screening method that is suitable for analyzing condensed tannin contents and structural composition directly in green plant tissue.

  1. Structural Elucidation of Metabolites of Synthetic Cannabinoid UR-144 by Cunninghamella elegans Using Nuclear Magnetic Resonance (NMR) Spectroscopy.

    Science.gov (United States)

    Watanabe, Shimpei; Kuzhiumparambil, Unnikrishnan; Fu, Shanlin

    2018-03-08

    The number of new psychoactive substances keeps on rising despite the controlling efforts by law enforcement. Although metabolism of the newly emerging drugs is continuously studied to keep up with the new additions, the exact structures of the metabolites are often not identified due to the insufficient sample quantities for techniques such as nuclear magnetic resonance (NMR) spectroscopy. The aim of the study was to characterise several metabolites of the synthetic cannabinoid (1-pentyl-1H-indol-3-yl) (2,2,3,3-tetramethylcyclopropyl) methanone (UR-144) by NMR spectroscopy after the incubation with the fungus Cunninghamella elegans. UR-144 was incubated with C. elegans for 72 h, and the resulting metabolites were chromatographically separated. Six fractions were collected and analysed by NMR spectroscopy. UR-144 was also incubated with human liver microsomes (HLM), and the liquid chromatography-high resolution mass spectrometry analysis was performed on the HLM metabolites with the characterised fungal metabolites as reference standards. Ten metabolites were characterised by NMR analysis including dihydroxy metabolites, carboxy and hydroxy metabolites, a hydroxy and ketone metabolite, and a carboxy and ketone metabolite. Of these metabolites, dihydroxy metabolite, carboxy and hydroxy metabolites, and a hydroxy and ketone metabolite were identified in HLM incubation. The results indicate that the fungus is capable of producing human-relevant metabolites including the exact isomers. The capacity of the fungus C. elegans to allow for NMR structural characterisation by enabling production of large amounts of metabolites makes it an ideal model to complement metabolism studies.

  2. Antioxidant activity and electrochemical elucidation of the enigmatic redox behavior of curcumin and its structurally modified analogues

    International Nuclear Information System (INIS)

    Jha, Niki S.; Mishra, Satyendra; Jha, Shailendra K.; Surolia, Avadhesha

    2015-01-01

    Highlights: • Structural analogues of curcumin have been synthesized. • Confirmation of redox behaviour emanates from H- shift from central methylene group in curcumin. • Mechanism of curcumin oxidation has been proposed. • Correlation between redox behavior and antioxidant activity has been established. - Abstract: Here, we report studies on the antioxidant activity and redox behavior of curcumin and its structurally modified synthetic analogues. We have synthesized a number of analogues of curcumin which abrogate its keto-enol tautomerism or substitute the methylene group at the centre of its heptadione moiety implicated in the hydride transfer and studied their redox property. From cyclic voltammetric studies, it is demonstrated that H- atom transfer from CH 2 group at the center of the heptadione link also plays an important role in the antioxidant properties of curcumin along with that of its phenolic –OH group. In addition, we also show that the conversion of 1, 3- dicarbonyl moiety of curcumin to an isosteric heterocycle as in pyrazole curcumin, which decreases its rotational freedom, leads to an improvement of its redox properties as well as its antioxidant activity

  3. Cryo-EM structures of the mammalian endo-lysosomal TRPML1 channel elucidate the combined regulation mechanism

    Directory of Open Access Journals (Sweden)

    Sensen Zhang

    2017-09-01

    Full Text Available Abstract TRPML1 channel is a non-selective group-2 transient receptor potential (TRP channel with Ca2+ permeability. Located mainly in late endosome and lysosome of all mammalian cell types, TRPML1 is indispensable in the processes of endocytosis, membrane trafficking, and lysosome biogenesis. Mutations of TRPML1 cause a severe lysosomal storage disorder called mucolipidosis type IV (MLIV. In the present study, we determined the cryo-electron microscopy (cryo-EM structures of Mus musculus TRPML1 (mTRPML1 in lipid nanodiscs and Amphipols. Two distinct states of mTRPML1 in Amphipols are added to the closed state, on which could represent two different confirmations upon activation and regulation. The polycystin-mucolipin domain (PMD may sense the luminal/extracellular stimuli and undergo a “move upward” motion during endocytosis, thus triggering the overall conformational change in TRPML1. Based on the structural comparisons, we propose TRPML1 is regulated by pH, Ca2+, and phosphoinositides in a combined manner so as to accommodate the dynamic endocytosis process.

  4. Templated Atom-Precise Galvanic Synthesis and Structure Elucidation of a [Ag 24 Au(SR) 18 ] − Nanocluster

    KAUST Repository

    Bootharaju, Megalamane Siddaramappa

    2015-11-27

    Synthesis of atom-precise alloy nanoclusters with uniform composition is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag24Au(SR)18]- cluster (SR: thiolate) using a pure [Ag25(SR)18]- cluster as a template. Conversely, the direct synthesis of Ag24Au cluster leads to a mixture of [Ag25-xAux(SR)18]-, x=1-8. Mass spectrometry and crystallography of [Ag24Au(SR)18]- reveal the presence of the Au heteroatom at the Ag25 center, forming Ag24Au. The successful exchange of the central Ag of Ag25 with Au causes perturbations in the Ag25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag25 and Ag24Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single-atom level.

  5. Applications of CE-ESI-MS/MS analysis to structural elucidation of methylenecyclohexane ozonolysis products in the particle phase.

    Science.gov (United States)

    Müller, Conny; Iinuma, Yoshiteru; Böge, Olaf; Herrmann, Hartmut

    2007-05-01

    The composition of secondary organic aerosol (SOA) from the gas phase ozonolysis of methylenecyclohexane was analyzed in a series of indoor aerosol chamber experiments. Capillary electrophoresis-electrospray ionization-ion trap mass spectrometry (CE/ESI-ITMS) was used for qualitative and quantitative analysis of SOA constituents. A number of dicarboxylic acids in the range of C(5)-C(6), such as adipic acid and glutaric acid, were found as major components of the organic products. Besides these smaller compounds, the formation of higher-molecular-weight compounds were observed under both neutral and acidic conditions. MS/MS experiments were carried out in order to obtain information on the monomer units and the structure of the dimers. MS(2) experiments of the two most prominent dimers with a mass-to-charge ratio (m/z) of 257 and m/z 273 yielded common fragments of m/z 83, 129 or 145. Based on the fragmentation patterns, these dimers are tentatively identified as carboxylate ester acids containing a unit of adipic acid in the structure. The dimer with m/z 257 was nearly 60% of the total detected compounds for both the neutral and acidic seed particle experiments.

  6. On the use of atomistic simulations to aid bulk metallic glasses structural elucidation with solid-state NMR.

    Science.gov (United States)

    Ferreira, Ary R; Rino, José P

    2017-08-24

    Solid-state nuclear magnetic resonance (ssNMR) experimental 27 Al metallic shifts reported in the literature for bulk metallic glasses (BMGs) were revisited in the light of state-of-the-art atomistic simulations. In a consistent way, the Gauge-Including Projector Augmented-Wave (GIPAW) method was applied in conjunction with classical molecular dynamics (CMD). A series of Zr-Cu-Al alloys with low Al concentrations were selected as case study systems, for which realistic CMD derived structural models were used for a short- and medium-range order mining. That initial procedure allowed the detection of trends describing changes on the microstructure of the material upon Al alloying, which in turn were used to guide GIPAW calculations with a set of abstract systems in the context of ssNMR. With essential precision and accuracy, the ab initio simulations also yielded valuable trends from the electronic structure point of view, which enabled an overview of the bonding nature of Al-centered clusters as well as its influence on the experimental ssNMR outcomes. The approach described in this work might promote the use of ssNMR spectroscopy in research on glassy metals. Moreover, the results presented demonstrate the possibility to expand the applications of this technique, with deeper insight into nuclear interactions and less speculative assignments.

  7. Local structure of alkalis in mixed-alkali borate glass to elucidate the origin of mixed-alkali effect

    Directory of Open Access Journals (Sweden)

    Yomei Tokuda

    2015-12-01

    Full Text Available We report the structural analysis of Na+ and Cs+ in sodium cesium borate crystals and glasses using 23Na and 133Cs magic-angle spinning nuclear magnetic resonance (MAS NMR spectroscopy. The composition dependence of NMR spectra of the borate was similar to that of the silicate: (1 the peak position of cesium borate crystals shifted to upfield for structures with larger Cs+ coordination numbers, (2 the MAS NMR spectra of xNa2O-yCs2O-3B2O3 (x = 0, 0.25, 0.5, 0.75, 1.0, x + y = 1 glass showed that the average coordination number (CN of both the alkali cations decreases with increasing Cs+/(Na+ + Cs+ ratio. However, the degree of decrement in borates is much smaller than that in silicates. We have considered that the small difference in CN is due to 4-coordinated B, because it is electrically compensated by the alkali metal ions resulting in the restriction of having various coordinations of O to alkali metal.

  8. Elucidation of Structural Elements for Selectivity across Monoamine Transporters: Novel 2-[(Diphenylmethyl)sulfinyl]acetamide (Modafinil) Analogues

    DEFF Research Database (Denmark)

    Okunola-Bakara, Oluyomi; Cao, Jianjing; Kopajtic, Theresa

    2014-01-01

    2-[(Diphenylmethyl)sulfinyl]acetamide (modafinil, (±)-1) is a unique dopamine uptake inhibitor that binds the dopamine transporter (DAT) differently than cocaine and may have potential for the treatment of psychostimulant abuse. To further investigate structural requirements for this divergent...... of the diphenyl rings of (±)-1 gave several amide analogues with improved binding affinity for DAT and robust selectivity over the serotonin transporter (SERT), whereas affinity improved at SERT over DAT for the p-halo-substituted amine analogues. Molecular docking studies, using a subset of analogues with DAT...... and SERT homology models, and functional data obtained with DAT (A480T) and SERT (T497A) mutants defined a role for TM10 in the substrate/inhibitor S1 binding sites of DAT and SERT....

  9. Phytochemical study of the trunk bark of Citharexylum spinosum L. growing in Tunisia: Isolation and structure elucidation of iridoid glycosides.

    Science.gov (United States)

    Saidi, Ilyes; Waffo-Téguo, Pierre; Ayeb-Zakhama, Asma E L; Harzallah-Skhiri, Fethia; Marchal, Axel; Ben Jannet, Hichem

    2018-02-01

    A phytochemical investigation of the trunk bark ethyl acetate extract of Citharexylum spinosum L. has led to the isolation of four previously undescribed iridoid glycosides, tunispinosides A-D, and five known phenylethanoid glycosides, verbascoside, leucosceptoside A, martynoside, isoverbascoside and plantainoside C, together with 4-hydroxy-2,6-dimethoxyphenyl 6'-O-vanilloyl-β-D-glucopyranoside, two 8,3'-neolignan glycosides, plucheosides D 1 -D 2 , coniferyl aldehyde, vanillic acid, syringic acid, ferulic acid and tyrosol. All compounds were isolated for the first time from C. spinosum. Their isolation was carried out using silica gel column and high performance liquid chromatography (HPLC). Structures were established by spectroscopic means including 1D and 2D NMR experiments, and spectrometric ESI-HRMS analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Structural elucidation of in vitro and in vivo metabolites of emodin in rats by LC -ESI-MS/MS

    International Nuclear Information System (INIS)

    Wang, D.; Zhu, Q.; Chen, G.; Liu, B.; Chen, L.

    2013-01-01

    Emodin is a widely occurring natural product and has been studied extensively for its varieties of pharmacological activity. In attempt to know more deeply about its metabolism, this paper investigated the metabolites of emodin in rats, including its in vitro conversion product by intestinal microflora and urinary metabolites. The detection of emodin metabolites was performed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) with negative ion mode. By comparing the changes of metabolites in molecular masses (delta M), product ions and retention times with those of the parent drug, six metabolites (8-O-methylemodin, omega-hydroxyemodin, x-hydroxyemodin, emodin glucuronide, hydroxyemodin glucuronide and emodin sulfate) were observed,and what is more, the metabolite hydroxyemodin glucuronide was first reported in this article. For some metabolites, identification of their precise structure needs to be confirmed by other techniques such as the 1H and 13C NMR. (author)

  11. 3-Ishwarone, a Rare Ishwarane Sesquiterpene from Peperomia scandens Ruiz & Pavon: Structural Elucidation through a Joint Experimental and Theoretical Study

    Directory of Open Access Journals (Sweden)

    Fernando M. dos S.

    2013-10-01

    Full Text Available 3-Ishwarone, (1, a sesquiterpene with a rare ishwarane skeleton, was isolated from Peperomia scandens Ruiz & Pavon (Piperaceae. Its structure was unambiguously determined by 1D- and 2D-NMR and infrared analyses, as well as by comparative theoretical studies which involved calculations of 13C-NMR chemical shifts, using the Density Functional Theory (DFT with the mPW1PW91 hybrid functional and Pople’s 6-31G(d basis set, and of vibrational frequencies, using the B3LYP hybrid functional and triple ζ Dunning’s correlation consistent basis set (cc-pVTZ, of (1 and three of its possible diastereomers, compounds 2–4.

  12. Elucidation of structural, vibrational and dielectric properties of transition metal (Co2+) doped spinel Mg-Zn chromites

    Science.gov (United States)

    Choudhary, Pankaj; Varshney, Dinesh

    2018-05-01

    Co2+ doped Mg-Zn spinel chromite compositions Mg0.5Zn0.5-xCoxCr2O4 (0.0 ≤ x ≤ 0.5) have been synthesized by the high-temperature solid state method. Synchrotron and X-ray diffraction (XRD) studies show single-phase crystalline nature. The structural analysis is validated by Rietveld refinement confirms the cubic structure with space group Fd3m. Crystallite size is estimated from Synchrotron XRD which was found to be 30-34 nm. Energy dispersive analysis confirms stoichiometric Mg0.5Zn0.5-xCoxCr2O4 composition. Average crystallite size distribution is estimated from imaging software (Image - J) of SEM is in the range of 100-250 nm. Raman spectroscopy reveals four active phonon modes, and a pronounced red shift is due to enhanced Co2+ concentration. Increased Co2+ concentration in Mg-Zn chromites shows a prominent narrowing of band gap from 3.46 to 2.97 eV. The dielectric response is attributed to the interfacial polarization, and the electrical modulus study supports non-Debye type of dielectric relaxation. Ohmic junctions (minimum potential drop) at electrode interface are active at lower levels of doping (x rise to a low-frequency semicircle as evidenced from the complex impedance analysis. The low dielectric loss and high ac conductivity of Co2+ doped Mg-Zn spinel chromites are suitable for power transformer applications at high frequencies.

  13. Crystal structures of protein phosphatase-1 bound to motuporin and dihydromicrocystin-LA: elucidation of the mechanism of enzyme inhibition by cyanobacterial toxins.

    Science.gov (United States)

    Maynes, Jason T; Luu, Hue A; Cherney, Maia M; Andersen, Raymond J; Williams, David; Holmes, Charles F B; James, Michael N G

    2006-02-10

    The microcystins and nodularins are tumour promoting hepatotoxins that are responsible for global adverse human health effects and wildlife fatalities in countries where drinking water supplies contain cyanobacteria. The toxins function by inhibiting broad specificity Ser/Thr protein phosphatases in the host cells, thereby disrupting signal transduction pathways. A previous crystal structure of a microcystin bound to the catalytic subunit of protein phosphatase-1 (PP-1c) showed distinct changes in the active site region when compared with protein phosphatase-1 structures bound to other toxins. We have elucidated the crystal structures of the cyanotoxins, motuporin (nodularin-V) and dihydromicrocystin-LA bound to human protein phosphatase-1c (gamma isoform). The atomic structures of these complexes reveal the structural basis for inhibition of protein phosphatases by these toxins. Comparisons of the structures of the cyanobacterial toxin:phosphatase complexes explain the biochemical mechanism by which microcystins but not nodularins permanently modify their protein phosphatase targets by covalent addition to an active site cysteine residue.

  14. Novel transglutaminase-like peptidase and C2 domains elucidate the structure, biogenesis and evolution of the ciliary compartment.

    Science.gov (United States)

    Zhang, Dapeng; Aravind, L

    2012-10-15

    C2 domains aid in the proper reconstruction of the Y-shaped linkers, which are key structures in the transitional zone of cilia, by allowing precise prediction of the multiple membrane-contacting and protein-protein interaction sites in these structures. These findings help decipher key events in the evolutionary separation of the ciliary and nuclear compartments in course of the emergence of the eukaryotic cell.

  15. Changes in the sialylation and sulfation of secreted thyrotropin in congenital hypothyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Gyves, P.W.; Gesundheit, N.; Thotakura, N.R.; Stannard, B.S.; DeCherney, G.S.; Weintraub, B.D. (National Institutes of Health, Bethesda, MD (USA))

    1990-05-01

    The authors have examined the oligosaccharide structure of secreted thyrotropin (TSH) in perinatal and mature rats with congenital primary hypothyroidism. Rat pituitaries from euthyroid control animals and those rendered hypothyroid by methimazole treatment were incubated with ({sup 3}H)glucosamine in vitro. Secreted TSH was purified, and oligosaccharides were enzymatically released and characterized by anion-exchange HPLC. In perinatal hypothyroid animals compared with control animals, oligosaccharides from TSH {alpha} and {beta} subunits contained more species with three or more negative charges. Moreover, perinatal hypothyroid animals demonstrated a dramatic increase in the ratio of sialylated to sulfated species within oligosaccharides of the same negative charge. In mature hypothyroid 9-week-old animals compared with control animals, changes were less pronounced, suggesting that endocrine regulation of oligosaccharide structure is dependent upon the maturational state of the animal. Together, these data provide direct evidence and characterization of specific changes in the structure of a secreted pituitary glycoprotein hormone occurring as a result of in vivo endocrine alterations during early development. Moreover, they provide a potential structural basis to explain the delayed clearance of both TSH and the gonadotropins with end-organ deficiency, which may have important implications for the in vivo biological activities of these hormones.

  16. Changes in the sialylation and sulfation of secreted thyrotropin in congenital hypothyroidism

    International Nuclear Information System (INIS)

    Gyves, P.W.; Gesundheit, N.; Thotakura, N.R.; Stannard, B.S.; DeCherney, G.S.; Weintraub, B.D.

    1990-01-01

    The authors have examined the oligosaccharide structure of secreted thyrotropin (TSH) in perinatal and mature rats with congenital primary hypothyroidism. Rat pituitaries from euthyroid control animals and those rendered hypothyroid by methimazole treatment were incubated with [ 3 H]glucosamine in vitro. Secreted TSH was purified, and oligosaccharides were enzymatically released and characterized by anion-exchange HPLC. In perinatal hypothyroid animals compared with control animals, oligosaccharides from TSH α and β subunits contained more species with three or more negative charges. Moreover, perinatal hypothyroid animals demonstrated a dramatic increase in the ratio of sialylated to sulfated species within oligosaccharides of the same negative charge. In mature hypothyroid 9-week-old animals compared with control animals, changes were less pronounced, suggesting that endocrine regulation of oligosaccharide structure is dependent upon the maturational state of the animal. Together, these data provide direct evidence and characterization of specific changes in the structure of a secreted pituitary glycoprotein hormone occurring as a result of in vivo endocrine alterations during early development. Moreover, they provide a potential structural basis to explain the delayed clearance of both TSH and the gonadotropins with end-organ deficiency, which may have important implications for the in vivo biological activities of these hormones

  17. Antimicrobial efficacy of phenanthrenequinone based Schiff base complexes incorporating methionine amino acid: Structural elucidation and in vitro bio assay

    Science.gov (United States)

    Arun, Thesingu Rajan; Raman, Natarajan

    2014-06-01

    This work focuses the synthesis and characterization of few novel mixed ligand Schiff base metal complexes and their biological activities. For deriving the structural aspects, spectral techniques such as FT-IR, UV-Vis., 1H NMR, Raman, EPR and the physicochemical characterizations including elemental analysis, molar conductance and magnetic susceptibility method have been involved. All the complexes adopt square planar geometry. DNA binding ability of these complexes has been explored using diverse techniques viz. UV-Vis. absorption, fluorescence spectroscopy, viscometry and cyclic voltammetry. These studies prove that CT-DNA binding of the complexes follows the intercalation mode. Comparative DNA oxidative cleavage ability of the complexes has been done under ultraviolet photo radiation on pUC19 DNA. In addition, the biocidal action of the complexes has been investigated against few pathogenic bacteria and fungi by disc diffusion method. Importantly, the amylase inhibition activity of Cu(II) complex has been explored. The amylase inhibition property has been found to be increased upon increasing the complex concentration.

  18. Cobalt-Catalyzed [2π + 2π] Cycloadditions of Alkenes: Scope, Mechanism, and Elucidation of Electronic Structure of Catalytic Intermediates

    Science.gov (United States)

    2015-01-01

    Aryl-substituted bis(imino)pyridine cobalt dinitrogen compounds, (RPDI)CoN2, are effective precatalysts for the intramolecular [2π + 2π] cycloaddition of α,ω-dienes to yield the corresponding bicyclo[3.2.0]heptane derivatives. The reactions proceed under mild thermal conditions with unactivated alkenes, tolerating both amine and ether functional groups. The overall second order rate law for the reaction, first order with respect to both the cobalt precatalyst and the substrate, in combination with electron paramagnetic resonance (EPR) spectroscopic studies established the catalyst resting state as dependent on the identity of the precatalyst and diene substrate. Planar S =1/2 κ3-bis(imino)pyridine cobalt alkene and tetrahedral κ2-bis(imino)pyridine cobalt diene complexes were observed by EPR spectroscopy and in the latter case structurally characterized. The hemilabile chelate facilitates conversion of a principally ligand-based singly occupied molecular orbital (SOMO) in the cobalt dinitrogen and alkene compounds to a metal-based SOMO in the diene intermediates, promoting C–C bond-forming oxidative cyclization. Structure–activity relationships on bis(imino)pyridine substitution were also established with 2,4,6-tricyclopentyl-substituted aryl groups, resulting in optimized catalytic [2π + 2π] cycloaddition. The cyclopentyl groups provide a sufficiently open metal coordination sphere that encourages substrate coordination while remaining large enough to promote a challenging, turnover-limiting C(sp3)–C(sp3) reductive elimination. PMID:26030841

  19. Structural elucidation and magnetic behavior evaluation of Cu-Cr doped BaCo-X hexagonal ferrites

    Science.gov (United States)

    Azhar Khan, Muhammad; Hussain, Farhat; Rashid, Muhammad; Mahmood, Asif; Ramay, Shahid M.; Majeed, Abdul

    2018-04-01

    Ba2-xCuxCo2CryFe28-yO46 (x = 0.0, 0.1, 0.2, 0.3, 0.4, y = 0.0, 0.2, 0.4, 0.6, 0.8) X-type hexagonal ferrites were synthesized via micro-emulsion route. The techniques which were applied to characterize the prepared samples are as follows: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Dielectric measurements and vibrating sample magnetometer (VSM). The structural parameters i.e. lattice constant (a, c), cell volume (V), X-ray density, bulk density and crystallite size of all the prepared samples were obtained using XRD analysis. The lattice parameters 'a' and 'c' increase from 5.875 Å to 5.934 Å and 83.367 Å to 83.990 Å respectively. The crystallite size of investigated samples lies in the range of 28-32 nm. The magnetic properties of all samples have been calculated by vibrating sample magnetometer (VSM) analysis. The increase in coercivity (Hc) was observed with the increase of doping contents. It was observed that the coercivity (Hc) of all prepared samples is inversely related to the crystalline size which reflects that all materials are super-paramagnetic. The dielectric parameters i.e. dielectric constant, dielectric loss, tangent loss etc were obtained in the frequency range of 1 MHz-3 GHz and followed the Maxwell-Wagner's model. The significant variation the dielectric parameters are observed with increasing frequency. The maximum Q value is obtained at ∼2 GHz due to which these materials are used for high frequency multilayer chip inductors.

  20. On the use of X-ray absorption spectroscopy to elucidate the structure of lutetium adenosine mono- and triphosphate complexes.

    Science.gov (United States)

    Mostapha, S; Berthon, C; Fontaine-Vive, F; Gaysinski, M; Guérin, L; Guillaumont, D; Massi, L; Monfardini, I; Solari, P L; Thomas, O P; Charbonnel, M C; Den Auwer, C

    2014-02-01

    chemical calculations has been implemented in order to assess the lutetium coordination arrangement for the two nucleotides. In all the complexes described in the article, the lutetium cation is coordinated by the phosphate groups of the nucleotide plus additional putative water molecules with various tridimensional arrangements. With AMP 1:2 and ATP 1:1 solid-state compounds, polynuclear complexes are assumed to be obtained. In contrast, with ATP 1:2 soluble compound, the Lu coordination sphere is saturated by two ATP ligands, and this favors the formation of a mononuclear complex. In order to further interpret the EXAFS data obtained at the Lu LIII edge, model structures have been calculated for the 1:1 and 1:2 ATP complexes. They are discussed and compared to the EXAFS best fit metrical parameters.

  1. One-pot microwave assisted synthesis and structural elucidation of novel ethyl 3-substituted-7-methylindolizine-1-carboxylates with larvicidal activity against Anopheles arabiensis

    Science.gov (United States)

    Chandrashekharappa, Sandeep; Venugopala, Katharigatta N.; Nayak, Susanta K.; Gleiser, Raquel M.; García, Daniel A.; Kumalo, Hezekiel M.; Kulkarni, Rashmi S.; Mahomoodally, Fawzi M.; Venugopala, Rashmi; Mohan, Mahendra K.; Odhav, Bharti

    2018-03-01

    In the present investigation a series of novel ethyl 3-substituted-7-methylindolizine-1-carboxylates was achieved by microwave assisted one-pot method. The purity of the compounds was ascertained by HPLC and structural elucidation of the title compounds was achieved by FT-IR, NMR (1H and 13C), LC-MS and elemental analysis. One randomly selected compound from the series was further studied by single crystal X-ray method for intra and intermolecular interactions. Larvicidal properties of the characterized compounds were evaluated against Anopheles arabiensis and it was found that indolizine pharmacophore influences larvicidal activity as we can see larvicidal activity for all the analogues. The synthesized analogues (2j, 2m and 2f) were the most potent compounds based on the functional groups on the indolizine pharmacophore for larvicidal assay.

  2. Isolation, structural elucidation, MS profiling, and evaluation of triglyceride accumulation inhibitory effects of benzophenone C-glucosides from leaves of Mangifera indica L.

    Science.gov (United States)

    Zhang, Yi; Han, Lifeng; Ge, Dandan; Liu, Xuefeng; Liu, Erwei; Wu, Chunhua; Gao, Xiumei; Wang, Tao

    2013-02-27

    Seventy percent ethanol-water extract from the leaves of Mangifera indica L. (Anacardiaceae) was found to show an inhibitory effect on triglyceride (TG) accumulation in 3T3-L1 cells. From the active fraction, six new benzophenone C-glucosides, foliamangiferosides A(3) (1), A(4) (2), C(4) (3), C(5) (4), C(6) (5), and C(7) (6) together with 11 known benzophenone C-glucosides (7-17) were obtained. In this paper, isolation, structure elucidation (1-6), and MS fragment cleavage pathways of all 17 isolates were studied. 1-6 showed inhibitory effects on TG and free fatty acid accumulation in 3T3-L1 cells at 10 μM.

  3. Structural modeling of the AhR:ARNT complex in the bHLH-PASA-PASB region elucidates the key determinants of dimerization.

    Science.gov (United States)

    Corrada, Dario; Denison, Michael S; Bonati, Laura

    2017-05-02

    Elucidation of the dimerization process of the aryl hydrocarbon receptor (AhR) with the AhR nuclear translocator (ARNT) is crucial for understanding the mechanisms underlying the functional activity of AhR, including mediation of the toxicity of environmental contaminants. In this work, for the first time a structural model of the AhR:ARNT dimer encompassing the entire bHLH-PASA-PASB domain region is proposed. It is developed by using a template-based modeling approach, relying on the recently available crystallographic structures of two dimers of homologous systems in the bHLH-PAS family of proteins: the CLOCK:BMAL1 and the HIF2α:ARNT heterodimers. The structural and energetic characteristics of the modeled AhR:ARNT protein-protein interface are determined by evaluating the variations in solvent accessible surface area, the total binding free energy and the per-residue free energy contributions obtained by the MM-GBSA method and the Energy Decomposition Analysis. The analyses of the intricate network of inter-domain interactions at the dimerization interfaces provide insights into the key determinants of dimerization. These are confirmed by comparison of the computational findings with the available experimental mutagenesis and functional analysis data. The results presented here on the AhR:ARNT dimer structure and interactions provide a framework to start analyzing the mechanism of AhR transformation into its functional DNA binding form.

  4. In-source collision-induced dissociation (IS-CID): Applications, issues and structure elucidation with single-stage mass analyzers.

    Science.gov (United States)

    Parcher, Jon F; Wang, Mei; Chittiboyina, Amar G; Khan, Ikhlas A

    2018-01-01

    A discussion of the definition, advantages, and issues with the formation of ions in the transition region between an electrospray ionization (ESI) source and the ion optics of a mass analyzer is presented. The various types of ions formed in the so-called in-source collision-induced dissociation (IS-CID) process are illustrated. Applications of IS-CID with single-stage mass analyzers, such as structure elucidation and quantitation, are demonstrated. The discussion is illustrated by examples of the in-source fragmentation of ginkgolides, which are marker compounds found only in Ginkgo biloba. Supercritical fluid chromatography (SFC) with non-aqueous eluents was used to achieve a fast resolution of the ginkgolides without the hydrolysis reactions possible with aqueous high-performance liquid chromatography (HPLC) eluents. In-source ion generation occurs at relatively high pressures (ca. 1-3 torr) compared to the low pressure normally observed in collision chambers of tandem mass spectrometry (MS/MS). As a result, the fragmentation process is complex and often generates ions other than the fragments observed with classic CID or the same ions at different intensities. The objective of the current tutorial is to illustrate the conditions under which single-stage, quadrupole or time-of-flight mass analyzers with electrospray or in-air (direct analysis in real time; DART) ionization can be used for quantitation and structure elucidation in a manner similar to that observed with MS/MS. While the low m/z (≤ [M±H] ± ) ions formed in-source often duplicate the ions observed in MS/MS systems, it is the focus of this discussion to illustrate the utility of in-source generated fragment ions that may not be observed or observed at different intensities than in the collision cells of MS/MS instruments. Copyright © 2017 John Wiley & Sons, Ltd.

  5. Thyrotropin-releasing hormone selectively stimulates human hair follicle pigmentation.

    Science.gov (United States)

    Gáspár, Erzsébet; Nguyen-Thi, Kim T; Hardenbicker, Celine; Tiede, Stephan; Plate, Christian; Bodó, Eniko; Knuever, Jana; Funk, Wolfgang; Bíró, Tamás; Paus, Ralf

    2011-12-01

    In amphibians, thyrotropin-releasing hormone (TRH) stimulates skin melanophores by inducing secretion of α-melanocyte-stimulating hormone in the pituitary gland. However, it is unknown whether this tripeptide neurohormone exerts any direct effects on pigment cells, namely, on human melanocytes, under physiological conditions. Therefore, we have investigated whether TRH stimulates pigment production in organ-cultured human hair follicles (HFs), the epithelium of which expresses both TRH and its receptor, and/or in full-thickness human skin in situ. TRH stimulated melanin synthesis, tyrosinase transcription and activity, melanosome formation, melanocyte dendricity, gp100 immunoreactivity, and microphthalmia-associated transcription factor expression in human HFs in a pituitary gland-independent manner. TRH also stimulated proliferation, gp100 expression, tyrosinase activity, and dendricity of isolated human HF melanocytes. However, intraepidermal melanogenesis was unaffected. As TRH upregulated the intrafollicular production of "pituitary" neurohormones (proopiomelanocortin transcription and ACTH immunoreactivity) and as agouti-signaling protein counteracted TRH-induced HF pigmentation, these pigmentary TRH effects may be mediated in part by locally generated melanocortins and/or by MC-1 signaling. Our study introduces TRH as a novel, potent, selective, and evolutionarily highly conserved neuroendocrine factor controlling human pigmentation in situ. This physiologically relevant and melanocyte sub-population-specific neuroendocrine control of human pigmentation deserves clinical exploration, e.g., for preventing or reversing hair graying.

  6. Multiple metals predict prolactin and thyrotropin (TSH) levels in men

    Energy Technology Data Exchange (ETDEWEB)

    Meeker, John D., E-mail: meekerj@umich.edu [Department of Environmental Health Sciences, University of Michigan School of Public Health, 6635 SPH Tower, 109 S. Observatory St., Ann Arbor, MI 48109 (United States); Rossano, Mary G. [Department of Animal and Food Sciences, University of Kentucky, Lexington, KY (United States); Protas, Bridget [Department of Epidemiology, Michigan State University, East Lansing, MI (United States); Diamond, Michael P.; Puscheck, Elizabeth [Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI (United States); Daly, Douglas [Grand Rapids Fertility and IVF, Grand Rapids, MI (United States); Paneth, Nigel [Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI (United States); Wirth, Julia J. [Department of Epidemiology, Michigan State University, East Lansing, MI (United States); Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI (United States)

    2009-10-15

    Exposure to a number of metals can affect neuroendocrine and thyroid signaling, which can result in adverse effects on development, behavior, metabolism, reproduction, and other functions. The present study assessed the relationship between metal concentrations in blood and serum prolactin (PRL) and thyrotropin (TSH) levels, markers of dopaminergic, and thyroid function, respectively, among men participating in a study of environmental influences on male reproductive health. Blood samples from 219 men were analyzed for concentrations of 11 metals and serum levels of PRL and TSH. In multiple linear regression models adjusted for age, BMI and smoking, PRL was inversely associated with arsenic, cadmium, copper, lead, manganese, molybdenum, and zinc, but positively associated with chromium. Several of these associations (Cd, Pb, Mo) are consistent with limited studies in humans or animals, and a number of the relationships (Cr, Cu, Pb, Mo) remained when additionally considering multiple metals in the model. Lead and copper were associated with non-monotonic decrease in TSH, while arsenic was associated with a dose-dependent increase in TSH. For arsenic these findings were consistent with recent experimental studies where arsenic inhibited enzymes involved in thyroid hormone synthesis and signaling. More research is needed for a better understanding of the role of metals in neuroendocrine and thyroid function and related health implications.

  7. Serum Thyrotropin and Phase of the Menstrual Cycle

    Directory of Open Access Journals (Sweden)

    Salvatore Benvenga

    2017-09-01

    Full Text Available About one-fifth of patients treated with levothyroxine have serum thyrotropin (TSH above target concentrations but, in approximately 15% of them, the cause of this TSH insufficient normalization remains unknown. We report the cases of two regularly menstruating women with known thyroid disease who had TSH levels consistently >3 mU/L (and sometimes above target levels during mid-cycle, but consistently lower serum levels during the follicular and luteal phases of menstrual cycle. A major TSH release by the thyrotrophs in response to high circulating levels of estradiol (E2 at mid-cycle may increase levels of TSH compared to other phases of the cycle. The increased TSH can be misinterpreted as refractory hypothyroidism if the woman is under L-T4 replacement therapy or as subclinical hypothyroidism if the woman is not. Our findings might have important implications for diagnosis and management of thyroid disease, suggesting to request serum TSH measurements outside of the periovulatory days.

  8. Tissue-Specific Posttranslational Modification Allows Functional Targeting of Thyrotropin

    Directory of Open Access Journals (Sweden)

    Keisuke Ikegami

    2014-11-01

    Full Text Available Thyroid-stimulating hormone (TSH; thyrotropin is a glycoprotein secreted from the pituitary gland. Pars distalis-derived TSH (PD-TSH stimulates the thyroid gland to produce thyroid hormones (THs, whereas pars tuberalis-derived TSH (PT-TSH acts on the hypothalamus to regulate seasonal physiology and behavior. However, it had not been clear how these two TSHs avoid functional crosstalk. Here, we show that this regulation is mediated by tissue-specific glycosylation. Although PT-TSH is released into the circulation, it does not stimulate the thyroid gland. PD-TSH is known to have sulfated biantennary N-glycans, and sulfated TSH is rapidly metabolized in the liver. In contrast, PT-TSH has sialylated multibranched N-glycans; in the circulation, it forms the macro-TSH complex with immunoglobulin or albumin, resulting in the loss of its bioactivity. Glycosylation is fundamental to a wide range of biological processes. This report demonstrates its involvement in preventing functional crosstalk of signaling molecules in the body.

  9. Computer-assisted structure elucidation from 13C-NMR-Spectra. I. The development of a three-dimensional structure code. II. The development of an isomer generating program

    International Nuclear Information System (INIS)

    Schuetz, V.

    1999-05-01

    The presented thesis consists of two separate programs which both aid the automated structure elucidation in the CSEARCH database system. A successful utilization of a large collection of NMR reference spectra for the prediction of chemical shift values is dependent on a strong correlation between the spectral data and the structural information via unique coding. By now, this was done using the two-dimensional HOSE code, which turned out to be insufficient whenever stereochemical effects other than cis/trans-isomerism contribute to the chemical shift values. Therefore, this new algorithm has been developed to derive the demanded three-dimensional descriptors. The calculation is performed by matching the query structures against pattern molecules taken from a carefully selected library of ring skeletons. No three-dimensional coordinates are necessary, since the algorithm elucidates the descriptors on base of two-dimensional structures having their stereocenters specified using 'up/down' bonds. The descriptors are defined as number of interactions over 3 to 5 bonds, number of cis-substituents over 1 to 2 ringbonds and markers for axial substituents. This approach of deriving descriptors for steric interactions has successfully extended the HOSE coding scheme and has been implemented into a neural network; both methods allow for high-quality prediction of 13 C-NMR chemical shift values. The second algorithm is an isomer generating program named GENERAL, which efficiently supports the structure elucidation process by calculating all mathematically possible structures to a given molecular formula. The resulting list of structures is exhaustive and free of redundancy. Besides the basic input information - like the molecular formula and the specification of structural fragments, constraints can be defined to restrict the number of resulting structures. The most valuable information is provided by state-of-the-art 2D-NMR experiments and can be easily incorporated into

  10. The thyroid nodule. Thyrotropin and peripheral thyroid hormones; Der Schilddruesenknoten. TSH und periphere Hormone

    Energy Technology Data Exchange (ETDEWEB)

    Zimny, M. [Klinikum Hanau (Germany). Inst. fuer Nuklearmedizin

    2008-09-15

    Thyrotropin, free triodothyronine and thyroxine represent the standard serological parameters for the diagnostic work-up of the thyroid but only a minority of thyroid nodules present with subclinical or overt thyroid disorders. Besides a review of the regulation and principle of function of thyroid hormones as well as the effects of subclinical or overt hyperthyroidism, the significant role of these parameters beyond the assessment of hyperthyroidism in thyroid nodules is discussed. There is evidence that the level of thyrotropin within the normal range is predictive for the relevance of autonomous functioning nodules and the risk of malignancy of non-functioning thyroid nodules. Furthermore, the ratio of triodothyronine and thyroxine indicates the etiology of hyperthyroidism. Thyrotropin represents the main parameter to determine the adequate dose of thyroid hormone therapy of thyroid nodules. (orig.)

  11. Structures of R- and T-state hemoglobin Bassett: elucidating the structural basis for the low oxygen affinity of a mutant hemoglobin.

    Science.gov (United States)

    Safo, Martin K; Abdulmalik, Osheiza; Lin, Hsiang Ru; Asakura, Toshio; Abraham, Donald J

    2005-02-01

    The crystal structures of R- and T-state hemoglobin (Hb) Bassett have been determined to 2.15 and 1.80 A resolution, respectively. Physiologically, Hb Bassett (alphaAsp94-->Ala) is characterized by a low affinity for oxygen, a reduced Bohr effect and low cooperativity, as well as being slightly unstable (compared with normal adult hemoglobin; HbA). Comparisons between the Hb Bassett structures and previously determined R- and T-state HbA structures revealed that this mutant shares similar tertiary and quaternary structures with other Hbs. However, this analysis did identify localized structural differences between R-state Hb Bassett and R-state HbA at the alpha1beta2 (alpha2beta1) dimer interface and at the beta-cleft. Specifically, the beta-FG corner has shifted closer to the alpha-C helix in the mutant R structure. In addition, four intersubunit hydrogen bonds found at the alpha1beta2 interfaces of native R-state Hb structures are abolished or weakened and subsequently replaced by two new intersubunit hydrogen bonds in R-state Hb Bassett. Remarkably, the newly formed hydrogen bonds in the R-state mutant structure are also observed in T-state Hb structures. At the beta-cleft, betaHis46, which is known to contribute to the Bohr effect in Hb, makes a unique hydrogen-bonding interaction with betaAsn139 in the R-state Hb Bassett. Unlike the R-state mutant, the T-state Hb Bassett structure does not display any significant structural changes at both the alpha1beta2 (alpha2beta1) dimer interface and the beta-cleft. Quite significantly, the mutation has led to removal of an interdimer repulsion involving alpha1Asp94 and beta2Asp99. The R- and T-state structures of Hb Bassett suggest a stereochemical basis for the observed functional properties of this mutant.

  12. Structure Elucidation of Mixed-Linker Zeolitic Imidazolate Frameworks by Solid-State (1)H CRAMPS NMR Spectroscopy and Computational Modeling.

    Science.gov (United States)

    Jayachandrababu, Krishna C; Verploegh, Ross J; Leisen, Johannes; Nieuwendaal, Ryan C; Sholl, David S; Nair, Sankar

    2016-06-15

    Mixed-linker zeolitic imidazolate frameworks (ZIFs) are nanoporous materials that exhibit continuous and controllable tunability of properties like effective pore size, hydrophobicity, and organophilicity. The structure of mixed-linker ZIFs has been studied on macroscopic scales using gravimetric and spectroscopic techniques. However, it has so far not been possible to obtain information on unit-cell-level linker distribution, an understanding of which is key to predicting and controlling their adsorption and diffusion properties. We demonstrate the use of (1)H combined rotation and multiple pulse spectroscopy (CRAMPS) NMR spin exchange measurements in combination with computational modeling to elucidate potential structures of mixed-linker ZIFs, particularly the ZIF 8-90 series. All of the compositions studied have structures that have linkers mixed at a unit-cell-level as opposed to separated or highly clustered phases within the same crystal. Direct experimental observations of linker mixing were accomplished by measuring the proton spin exchange behavior between functional groups on the linkers. The data were then fitted to a kinetic spin exchange model using proton positions from candidate mixed-linker ZIF structures that were generated computationally using the short-range order (SRO) parameter as a measure of the ordering, clustering, or randomization of the linkers. The present method offers the advantages of sensitivity without requiring isotope enrichment, a straightforward NMR pulse sequence, and an analysis framework that allows one to relate spin diffusion behavior to proposed atomic positions. We find that structures close to equimolar composition of the two linkers show a greater tendency for linker clustering than what would be predicted based on random models. Using computational modeling we have also shown how the window-type distribution in experimentally synthesized mixed-linker ZIF-8-90 materials varies as a function of their composition. The

  13. Structural elucidation and toxicity assessment of degraded products of aflatoxin B1 and B2 by aqueous extracts of Trachyspermum ammi

    Directory of Open Access Journals (Sweden)

    Wajiha eIram

    2016-03-01

    Full Text Available In this study aqueous extract of seeds and leaves of Trachyspermum ammi were evaluated for their ability to detoxify aflatoxin B1 and B2 (AFB1; 100 µg L-1 and AFB2; 50 µg L-1 by In Vitro and In Vivo assays. Results indicated that T. ammi seeds extract was found to be highly significant (P < 0.05 in degrading AFB1 and AFB2 i.e. 92.8% and 91.9% respectively. However T. ammi leaves extract proved to be less efficient in degrading these aflatoxins, under optimized conditions i.e., pH 8, temperature 30˚C and incubation period of 72h. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that eight degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that T. ammi seeds extract can be used as an effective tool for the detoxification of aflatoxins.

  14. Structural Elucidation and Toxicity Assessment of Degraded Products of Aflatoxin B1 and B2 by Aqueous Extracts of Trachyspermum ammi.

    Science.gov (United States)

    Iram, Wajiha; Anjum, Tehmina; Iqbal, Mazhar; Ghaffar, Abdul; Abbas, Mateen

    2016-01-01

    In this study aqueous extract of seeds and leaves of Trachyspermum ammi were evaluated for their ability to detoxify aflatoxin B1 and B2 (AFB1; 100 μg L(-1) and AFB2; 50 μg L(-1)) by in vitro and in vivo assays. Results indicated that T. ammi seeds extract was found to be significant (P < 0.05) in degrading AFB1 and AFB2 i.e., 92.8 and 91.9% respectively. However, T. ammi leaves extract proved to be less efficient in degrading these aflatoxins, under optimized conditions i.e., pH 8, temperature 30°C and incubation period of 72 h. The structural elucidation of degraded toxin products by LCMS/MS analysis showed that eight degraded products of AFB1 and AFB2 were formed. MS/MS spectra showed that most of the products were formed by the removal of double bond in the terminal furan ring and modification of lactone group indicating less toxicity as compared to parent compounds. Brine shrimps bioassay further confirmed the low toxicity of degraded products, showing that T. ammi seeds extract can be used as an effective tool for the detoxification of aflatoxins.

  15. ISOLATION, STRUCTURE ELUCIDATION, IDENTIFICATION AND QUANTITATIVE ANALYSIS OF 1’-ACETOXYCHAVICOL (ACA FROM THE ROOTS OF CHLOROPHYTUM BORIVILIUANUM (SAFED MUSLI

    Directory of Open Access Journals (Sweden)

    ZUNOLIZA ABDULLAH

    2017-01-01

    Full Text Available Chlorophytum borivilianum (safed musli is a medicinally important plant. Its roots are being employed in folk medicine. Presently, the crude extract of C. borivilianum has been consumed for the treatment such as anti-diabetic, antiaging, anti-oxidant, anti-ulcer and anti-inflammatory and previous studies have been carried out to further confirm these remarkable bioactivities of C. borivilianum. In this research, 1’-acetoxychavicol acetate (ACA was isolated from the roots of C. borivilianum. The structure of ACA was elucidated based on the spectral data of 1H NMR, 13C NMR, DEPT, COSY, HMBC, HMQC and also based on the comparison with the previous literature data. ACA was isolated in an isocratic elution that eluted with hexane and ethyl acetate in the ratio of 10:0.25. In the HPLC analysis, the separation of the crude methanol extract was completed within 20 min and the retention time of ACA in the sample was 7.31 min. The regression equation of the calibration curve was developed and the correlation coefficient was found to be 0.991. This is the first report regarding the presence of ACA in C. borivilianum as well as its genus. For the first time, a high performance liquid chromatographic (HPLC method with photodiode array detection was developed for the quantitative determination and identification of ACA.

  16. Structural elucidation of novel bioactive compound (2-chloro-1-(2-chlorocyclopropyl-2-(4-nitrophenylethanone from basidiomycetous fungus Lentinus squarrosulus

    Directory of Open Access Journals (Sweden)

    Usha N.

    2016-02-01

    Full Text Available While screening for bioactive compounds from macrofungi of Western Ghats of Karnataka, Lentinus squarrosulus a member of polyporaceae was collected and mycelium of the fungus was obtained on potato dextrose agar medium and cultured in a liquid medium (containing 2% glucose, 1% peptone and 2% yeast extract for 20 days on a rotary shaker for the production of secondary metabolites. The cell free culture fluid (100ml was subjected to solvent extraction with dichloromethane (100ml and the extract was evaluated for antimicrobial activity by agar diffusion method and cytotoxic activity of the extract was also determined by MTT and SRB assay on MCF7 cell line. The results revealed that the dichloromethane extract was inhibitory against Escherichia coli, Enterobacter aerogenes, Staphylococcus aureus and Bacillus subtilus and also fungi such as Aspergillus niger, Fusarium solani and Trichoderma harzianum. The extract showed 13-27% cell inhibition at 63-1000 µg/ml concentration by MTT and SRB assays on MCF7 cell line. The structural elucidation of the compound by spectroscopic NMR (1H and C13, IR and mass spectrometric analysis confirmed the presence of 2-chloro-1-(2-chlorocyclopropyl-2-(4-nitrophenylethanone responsible for antimicrobial and cytotoxic activity.

  17. Structural elucidation of a water-insoluble glucan produced by a glucosyltransferase of Streptococcus mutans 6715 by chemical and instrumental analysis

    International Nuclear Information System (INIS)

    Davis, H.M.

    1985-01-01

    The structure of a water-insoluble polysaccharide produced by the glucosyltransferase of Streptococcus mutans 6715 has been elucidated through the use of periodate oxidation, Smith degradation, dextranase digestion, concanavalin A binding studies, methylation followed by methanolysis, reductive cleavage and gas chromatographic-mass spectroscopic analysis, carbon-13 nuclear magnetic resonance and fast atom bombardment mass spectroscopy. These studies show that the water-insoluble glucan is comprised of 67% α-(1-3) linkages in a contiguous backbone with the remaining 33% existing as α-(1-6) linkages possibly as linear residues extending from α-(1-6) branch points. 14% of the residues exist as branch points and the ratio of linear extending α-(1-3) residues in the backbone to linear extending α-(1-6) residues in the side chain was found to be 5:2. Dextranase digestion and Smith degradation both gave rise to a high molecular weight fraction which is only α-(1-3) linked. In addition, the average length of the side chains was shown to not exceed 3 residues

  18. Serum thyrotropin levels following levothyroxine administration at breakfast.

    Science.gov (United States)

    Perez, Camila Luhm Silva; Araki, Fernanda Sumire; Graf, Hans; de Carvalho, Gisah Amaral

    2013-07-01

    Hypothyroidism is treated with oral levothyroxine. Some patients fail to attain adequate control because of poor compliance. Delaying breakfast to take levothyroxine on an empty stomach can decrease adherence to hypothyroidism treatment. The objective of this study was to evaluate whether administering levothyroxine with breakfast can maintain thyrotropin (TSH) levels in the therapeutic range, without major clinical changes. A prospective, randomized, open-label, crossover study was conducted to compare usual levothyroxine administration while in a fasting state with administration during breakfast. From September 2008 to April 2009, 45 patients with primary hypothyroidism who received levothyroxine were recruited. The patients completed 180 days of the protocol and were randomized to 90 days of each levothyroxine administration regimen (while fasting or with breakfast). Clinical and biochemical analyses were performed at baseline and on days 45, 90, 135, and 180. The primary outcome was TSH level. Forty-two patients completed the protocol. The TSH level was higher for levothyroxine administration with breakfast than while fasting (2.89 vs. 1.9 mIU/L, p=0.028). Uncontrolled hypothyroidism (TSH ≥3.5 mIU/L) occurred regardless of the type of levothyroxine administration (p=0.26). No risk factors were identified for TSH elevation. Levothyroxine administration with breakfast could be an alternative regimen for patients who have adherence difficulties due to the need for delaying intake, and is more likely to cause variability in the TSH level, meaning the patient should be followed more closely. For patients in whom a specific serum TSH goal is important, taking levothyroxine while fasting is recommended.

  19. Metformin Does Not Suppress Serum Thyrotropin by Increasing Levothyroxine Absorption

    Science.gov (United States)

    Al-Alusi, Mostafa A.; Du, Lin; Li, Ning; Yeh, Michael W.; He, Xuemei; Braverman, Lewis E.

    2015-01-01

    Background: Levothyroxine (LT4) absorption is affected by concomitant ingestion of certain minerals, medications, and foods. It has been hypothesized that metformin may suppress serum thyrotropin (TSH) concentrations by enhancing LT4 absorption or by directly affecting the hypothalamic–pituitary axis. This study examined the effect of metformin ingestion on LT4 absorption, as assessed by serum total thyroxine (TT4) concentrations. Methods: A modified Food and Drug Administration LT4 bioequivalence protocol was applied to healthy, metformin-naïve, euthyroid adult volunteers. Following an overnight fast, 600 μg LT4 was administered orally. Serum TT4 concentrations were measured at baseline and at 0.5, 1, 1.5, 2, 4, and 6 h following LT4 administration. Measurements were performed before and after one week of metformin ingestion (850 mg three times daily). Peak serum TT4 concentrations, time to peak TT4 concentrations, and area under the concentration-time curve (AUC) were calculated. Results: Twenty-six subjects (54% men, 27% white, age 33 ± 10 years) were studied. There were no significant differences in peak serum TT4 concentrations (p = 0.13) and time to peak TT4 concentrations (p = 0.19) before and after one week of metformin use. A trend toward reduced TT4 AUC was observed after metformin ingestion (pre-metformin 3893 ± 568 μg/dL-min, post-metformin 3765 ± 588 μg/dL-min, p = 0.09). Conclusions: LT4 absorption is unchanged by concomitant metformin ingestion. Mechanisms other than increased LT4 absorption may be responsible for the suppressed TSH concentrations observed in patients ingesting both drugs. PMID:26191653

  20. Osteoporosis and thyrotropin-suppressive therapy: reduced effectiveness of alendronate.

    Science.gov (United States)

    Panico, Annalisa; Lupoli, Gelsy Arianna; Fonderico, Francesco; Marciello, Francesca; Martinelli, Addolorata; Assante, Roberta; Lupoli, Giovanni

    2009-05-01

    Many reports of the effect of exogenous thyroxine therapy on bone mineral density (BMD) show a relationship between excess thyroid hormone administration and osteoporosis. The aim of this study was to evaluate the effect of antibone resorptive agents, in particular alendronate (ALN) on BMD in postmenopausal osteoporotic women with thyroid carcinoma who were receiving long-term thyrotropin (TSH)-suppressive therapy with thyroxine. Seventy-four postmenopausal women with low BMD (T-score or =0.05 and < or =0.1 microU/mL) for about 3-9 years were selected for the study. The patients were divided into three groups according to the length of levothyroxine (LT(4)) treatment prior to the beginning of the study: group A (TSH-suppressive therapy for about 3 years), group B (for about 6 years), and group C (for about 9 years). These patients were compared with 74 matched women not taking LT(4). All patients and controls were treated with bisphosphonates, calcium, and vitamin D for 2 years and evaluated. After 24 months of treatment group A showed a 7.8% increase in lumbar BMD; group B, a 4.6% increase; and group C, a 0.86% increase. In the control group BMD increased 8.2%. A significant difference was found in both lumbar and femoral BMD increase among the three groups: group C had a lower BMD increase than group A (p < 0.001) and B (p < 0.001). In postmenopausal women who were receiving adequate amounts of calcium and vitamin D in their diet ALN was less effective for those who were also receiving TSH-suppressive doses of LT(4) for either 6 or 9 years. The positive effect of ALN on BMD was less for longer periods of LT(4) treatment. It seems likely that other bisphosphonates would also be less effective in increasing BMD in postmenopausal women receiving TSH-suppressing doses of LT(4).

  1. Anti- and Pro-Lipase Activity of Selected Medicinal, Herbal and Aquatic Plants, and Structure Elucidation of an Anti-Lipase Compound

    Directory of Open Access Journals (Sweden)

    Muhammad Abubakar Ado

    2013-11-01

    Full Text Available Plants that help in slowing down the digestion of triacylglycerols (TAGs in the pancreas and small intestine of humans play an important role in the reduction of obesity. On the other hand, there may be plants or plant parts that stimulate intestinal lipolytic activity, thus contributing to greater TAG assimilation. The aim of this study was to evaluate the aqueous methanolic extracts of ninety eight (98 medicinal, herbal and aquatic plant materials from Malaysia for their effect on porcine pancreatic lipase (PPL activity and to identify the structure of an anti-lipase compound from one of the sources. The degree of inhibition was also quantified as relative to orlistat activity against PPL (orlistat equivalents. Results revealed that while 19.4% of the extracts were found to have anti-lipase activity ≥80%, 12% were actually found to promote PPL activity. Twenty two percent (22.4% exhibited moderate inhibition (41%–80% and 2% were neutral toward PPL activity. The ripe fruit of Averrhoa carambola and the leaves of Archidendron jiringa (Jack I.C Nielsen L. (jering, Cynometra cauliflora (nam-nam and Aleurites moluccana (L. Willd (candle nut/buah keras had the highest (100% anti-lipase activity and are equivalent to 0.11 µg orlistat/mL. Plants that stimulated lipase activity included Pimpinella anisum L. (aniseed/jintan manis, activating the enzyme by 186.5%. Kaempferol 3-O-rhamnoside was isolated from the ethyl acetate fraction of C. cauliflora leaves and found to be an active lipase inhibitor. The structure was elucidated using 1H-NMR, 13C-NMR and 2D-NMR analyses.

  2. Application of high-field n.m.r. spectroscopy to the structural elucidation of natural products. The structure of rubellin, a noval bufadienolide glycoside from Urginea rubella

    International Nuclear Information System (INIS)

    Steyn, P.S.; Van Heerden, F.R.; Vleggaar, R.

    1986-01-01

    The structure and absolute configuration of rubellin, the major toxic principle of Urginea rubella, was determined by application of high-field 1 H n.m.r. spectroscopy. Rubellin proved to be a bufadienolide glycoside with the carbohydrate moiety doubly linked to the aglycone at the 2α- and 3β- positions

  3. Structural Elucidation of a Novel Polysaccharide from Pseudostellaria heterophylla and Stimulating Glucose Uptake in Cells and Distributing in Rats by Oral.

    Science.gov (United States)

    Chen, Jinlong; Pang, Wensheng; Shi, Wentao; Yang, Bin; Kan, Yongjun; He, Zhaodong; Hu, Juan

    2016-09-14

    The semi-refined polysaccharide of Pseudostellaria heterophylla is a complex polysaccharide that exhibits significantly hypoglycemic activities. A novel homogeneous polysaccharide, named as H-1-2, was isolated from the semi-refined polysaccharide. The mean molecular weight of H-1-2 was 1.4 × 10⁴ Da and it was only composed of d-glucose monosaccharide. Structure elucidation indicated that H-1-2 contains pyranride, and has the characteristics of the α-iso-head configuration, a non-reducing end (T-), 4-, 1,6-, and 1,4,6-connection, in all four ways to connect glucose. H-1-2 was a type of glucan, where chemical combination exists in the main chain between 1→4 linked glucose, and contains a small amount of 1,6-linked glucose, which was in the branched chain. In vitro HepG2, 3T3-L1, and L6 cells were used to assess cellular glucose consumption and cellular glucose uptake by glucose oxidase, and the transport of 2-NBDG fluorescence probe results showed that H-1-2 could clearly increase glucose uptake and utilization in muscle and adipose cells, which is beneficial to screen for in the discovery of anti-diabetes lead compounds. H-1-2 was labeled with radioisotopes ((99m)Tc-pertechnetate). (99m)Tc-labeled-H-1-2 was performed by SPECT/CT analysis images after oral administration in rats. At 4 h post ingestion, about 50% of the radioactivity was observed in the intestine. No significant radioactivity was found in the heart, liver, and kidney, conjecturing that absorption of (99m)Tc-labeled H-1-2 might, via intestinal mucosa, be absorbed into systemic circulation. This problem, as to whether the polysaccharide is absorbed orally, will need further examination.

  4. Preparation of standards of triiodothyronine, thyroxine and thyrotropin; Prepracion de estandares de triyodotironina, tiroxina y tirotrofina

    Energy Technology Data Exchange (ETDEWEB)

    Lavalley E, C.; Delgado S, B.; Ruiz J, A.; Zambrano A, F

    1991-10-15

    The standards preparation requires of certain basic principles, some of which are described in this work, which was made with the purpose of establishing the most appropriate conditions for the preparation of standards of triiodothyronine, thyroxine and thyrotropin to be used in radioimmunoanalysis essays. The diverse standards show a balanced displacement, that which is observed in the graphs presented in this work. (Author)

  5. Parity and 11-Year Serum Thyrotropin and Thyroid Autoantibody Change: A Longitudinal Population-Based Study

    DEFF Research Database (Denmark)

    Bjergved, Lena; Carlé, Allan; Jørgensen, Torben

    2016-01-01

    thyrotropin (TSH), as well as change in thyroid peroxidase autoantibody (TPOAb) status. A random sample of 4649 people aged 18-65 years participated in a population-based study in the period 1997-1998. In the study presented here, 1749 non-pregnant women with no history of thyroid disease were included who...

  6. Microbial communities in sediments of Lagos Lagoon, Nigeria: Elucidation of community structure and potential impacts of contamination by municipal and industrial wastes

    Directory of Open Access Journals (Sweden)

    Chioma C Obi

    2016-08-01

    Full Text Available Estuarine sediments are significant repositories of anthropogenic contaminants, and thus understanding the impacts of contamination upon microbial communities in these environments is important to understand potential effects on estuaries as a whole. The Lagos Lagoon (Nigeria is one of Africa’s largest estuarine ecosystems, and is impacted by hydrocarbon pollutants and other industrial and municipal wastes. The goal of this study was to elucidate microbial community structure in Lagos Lagoon sediments to identify groups that may be adversely affected by contamination, and those that may serve as degraders of environmental contaminants, especially polynuclear aromatic hydrocarbons (PAH. Sediment samples were collected from sites that ranged in types and levels of anthropogenic impacts. Sediments were characterized for a range of physicochemical properties, and microbial community structure was determined by Illumina sequencing of 16S rRNA gene sequences. Microbial diversity (species richness and evenness in the Apapa and Eledu sediments was reduced compared to that of the Ofin site, and communities of both of the former two were dominated by a single operational taxonomic unit (OTU assigned to the family Helicobacteraceae (Epsilonproteobacteria. In the Ofin community, Epsilonproteobacteria were minor constituents, and major groups were Cyanobacteria, Bacteroidetes and Firmicutes, which were all minor in the Apapa and Eledu sediments. Sediment oxygen demand (SOD, a broad indicator of contamination, was identified by multivariate analyses as strongly correlated with variation in alphadiversity. Environmental variables that explained betadiversity patterns included SOD, as well as levels of naphthalene, acenaphthylene, cobalt, cadmium, total organic matter or nitrate. Of 582 OTU identified, abundance of 167 was significantly correlated (false discovery rate q ≤ 0.05 to environmental variables. The largest group of OTU correlated with PAH levels

  7. Structure elucidation of the diagnostic product ion at m/z 97 derived from androst-4-en-3-one-based steroids by ESI-CID and IRMPD spectroscopy

    NARCIS (Netherlands)

    Thevis, M.; Beuck, S.; Hoeppner, S.; Thomas, A.; Held, J.; Schaefer, M.; Oomens, J.; Schaenzer, W.

    2012-01-01

    Structure elucidation of steroids by mass spectrometry has been of great importance to various analytical arenas and numerous studies were conducted to provide evidence for the composition and origin of (tandem) mass spectrometry-derived product ions used to characterize and identify steroidal

  8. Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, Abdul, E-mail: abdulmajeed2276@gmail.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F. [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, King Saud University, PO Box 800, Riyadh 11421 (Saudi Arabia); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-06-15

    Rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm{sup −1.} Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b{sub VI}). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} ferrites. • The crystallite size was found

  9. Principles and determinants of G-protein coupling by the rhodopsin-like thyrotropin receptor.

    Directory of Open Access Journals (Sweden)

    Gunnar Kleinau

    Full Text Available In this study we wanted to gain insights into selectivity mechanisms between G-protein-coupled receptors (GPCR and different subtypes of G-proteins. The thyrotropin receptor (TSHR binds G-proteins promiscuously and activates both Gs (cAMP and Gq (IP. Our goal was to dissect selectivity patterns for both pathways in the intracellular region of this receptor. We were particularly interested in the participation of poorly investigated receptor parts.We systematically investigated the amino acids of intracellular loop (ICL 1 and helix 8 using site-directed mutagenesis alongside characterization of cAMP and IP accumulation. This approach was guided by a homology model of activated TSHR in complex with heterotrimeric Gq, using the X-ray structure of opsin with a bound G-protein peptide as a structural template.We provide evidence that ICL1 is significantly involved in G-protein activation and our model suggests potential interactions with subunits G alpha as well as G betagamma. Several amino acid substitutions impaired both IP and cAMP accumulation. Moreover, we found a few residues in ICL1 (L440, T441, H443 and helix 8 (R687 that are sensitive for Gq but not for Gs activation. Conversely, not even one residue was found that selectively affects cAMP accumulation only. Together with our previous mutagenesis data on ICL2 and ICL3 we provide here the first systematically completed map of potential interfaces between TSHR and heterotrimeric G-protein. The TSHR/Gq-heterotrimer complex is characterized by more selective interactions than the TSHR/Gs complex. In fact the receptor interface for binding Gs is a subset of that for Gq and we postulate that this may be true for other GPCRs coupling these G-proteins. Our findings support that G-protein coupling and preference is dominated by specific structural features at the intracellular region of the activated GPCR but is completed by additional complementary recognition patterns between receptor and G

  10. Principles and determinants of G-protein coupling by the rhodopsin-like thyrotropin receptor.

    Science.gov (United States)

    Kleinau, Gunnar; Jaeschke, Holger; Worth, Catherine L; Mueller, Sandra; Gonzalez, Jorge; Paschke, Ralf; Krause, Gerd

    2010-03-18

    In this study we wanted to gain insights into selectivity mechanisms between G-protein-coupled receptors (GPCR) and different subtypes of G-proteins. The thyrotropin receptor (TSHR) binds G-proteins promiscuously and activates both Gs (cAMP) and Gq (IP). Our goal was to dissect selectivity patterns for both pathways in the intracellular region of this receptor. We were particularly interested in the participation of poorly investigated receptor parts.We systematically investigated the amino acids of intracellular loop (ICL) 1 and helix 8 using site-directed mutagenesis alongside characterization of cAMP and IP accumulation. This approach was guided by a homology model of activated TSHR in complex with heterotrimeric Gq, using the X-ray structure of opsin with a bound G-protein peptide as a structural template.We provide evidence that ICL1 is significantly involved in G-protein activation and our model suggests potential interactions with subunits G alpha as well as G betagamma. Several amino acid substitutions impaired both IP and cAMP accumulation. Moreover, we found a few residues in ICL1 (L440, T441, H443) and helix 8 (R687) that are sensitive for Gq but not for Gs activation. Conversely, not even one residue was found that selectively affects cAMP accumulation only. Together with our previous mutagenesis data on ICL2 and ICL3 we provide here the first systematically completed map of potential interfaces between TSHR and heterotrimeric G-protein. The TSHR/Gq-heterotrimer complex is characterized by more selective interactions than the TSHR/Gs complex. In fact the receptor interface for binding Gs is a subset of that for Gq and we postulate that this may be true for other GPCRs coupling these G-proteins. Our findings support that G-protein coupling and preference is dominated by specific structural features at the intracellular region of the activated GPCR but is completed by additional complementary recognition patterns between receptor and G-protein subtypes.

  11. Intrauterine Zn Deficiency Favors Thyrotropin-Releasing Hormone-Increasing Effects on Thyrotropin Serum Levels and Induces Subclinical Hypothyroidism in Weaned Rats

    Directory of Open Access Journals (Sweden)

    Viridiana Alcántara-Alonso

    2017-10-01

    Full Text Available Individuals who consume a diet deficient in zinc (Zn-deficient develop alterations in hypothalamic-pituitary-thyroid axis function, i.e., a low metabolic rate and cold insensitivity. Although those disturbances are related to primary hypothyroidism, intrauterine or postnatal Zn-deficient adults have an increased thyrotropin (TSH concentration, but unchanged thyroid hormone (TH levels and decreased body weight. This does not support the view that the hypothyroidism develops due to a low Zn intake. In addition, intrauterine or postnatal Zn-deficiency in weaned and adult rats reduces the activity of pyroglutamyl aminopeptidase II (PPII in the medial-basal hypothalamus (MBH. PPII is an enzyme that degrades thyrotropin-releasing hormone (TRH. This hypothalamic peptide stimulates its receptor in adenohypophysis, thereby increasing TSH release. We analyzed whether earlier low TH is responsible for the high TSH levels reported in adults, or if TRH release is enhanced by Zn deficiency at weaning. Dams were fed a 2 ppm Zn-deficient diet in the period from one week prior to gestation and up to three weeks after delivery. We found a high release of hypothalamic TRH, which along with reduced MBH PPII activity, increased TSH levels in Zn-deficient pups independently of changes in TH concentration. We found that primary hypothyroidism did not develop in intrauterine Zn-deficient weaned rats and we confirmed that metal deficiency enhances TSH levels since early-life, favoring subclinical hypothyroidism development which remains into adulthood.

  12. Elucidation of crystal and electronic structures within highly strained BiFeO3 by transmission electron microscopy and first-principles simulation

    OpenAIRE

    Bae, In-Tae; Kov?cs, Andr?s; Zhao, Hong Jian; ??iguez, Jorge; Yasui, Shintaro; Ichinose, Tomohiro; Naganuma, Hiroshi

    2017-01-01

    Crystal and electronic structures of ~380?nm BiFeO3 film grown on LaAlO3 substrate are comprehensively studied using advanced transmission electron microscopy (TEM) technique combined with first-principles theory. Cross-sectional TEM images reveal the BiFeO3 film consists of two zones with different crystal structures. While zone II turns out to have rhombohedral BiFeO3, the crystal structure of zone I matches none of BiFeO3 phases reported experimentally or predicted theoretically. Detailed ...

  13. Radioimmunological studies of the thyrotropic function of the hypophysis under the effect of the thyrotropin-releasing hormone in thyroid diseases

    International Nuclear Information System (INIS)

    Vakulenko, A.D.; Matveenko, E.G.; Simakova, G.M.; Sorokina, V.G.; Golubnichaya, L.P.; Dobrova, G.S.

    1979-01-01

    The synthetic thyrotropin-releasing-hormone was stream-injected intravenously to 124 patients and 16 healthy people in doses of 200 μg. It was tolerated satisfactorily at the first and repeated injections. The radioimmunologic method was used prior to the test and 30 min after it to examine thyrotropin content in blood. In normal state the stimulation would result in 3.5-fold increase in thyrotropin level on the average. The hypophysial reserve of thyrotropin was significantly lower in cases of diffuse toxic goiter in grave and semigrave forms and toxic adenoma. It was significantly higher at primary hypothyrosis and retained at nodular euthyroid goiter, neupocirculatopy dystonia and mild thyrotoxicosis. At thyroid gland disturbances the test with thyrotropin-releasing-hormone is of diagnostic value at primary hypothyrosis in the initial latent period; besides, it can be used for control of substitution therapy and as a supplementary test at thyrotoxicosis

  14. NMR and biophysical elucidation of structural effects on extra N-terminal methionine residue of recombinant amphibian RNases from Rana catesbeiana.

    Science.gov (United States)

    Hsu, Chun-Hua; Pan, Yun-Ru; Liao, You-Di; Wu, Shih-Hsiung; Chen, Chinpan

    2010-08-01

    The stability, structures and steric hindrances of recombinant RNases 2 and 4 expressed in bacteria were studied by circular dichroism (CD) and NMR techniques, and the results were compared with those of their authentic RNases extracted from oocytes of Rana catesbeiana. Although the overall structures of the recombinant and authentic proteins are almost identical, the extra N-terminal Met residue of the recombinant protein remarkably affects catalytic activity and stability. NMR chemical shift comparison of recombinant RNases and the authentic proteins indicated that the structural differences are mainly confined to the N-terminal helical and S2 anti-parallel beta-sheet regions. Significant shift changes for the residues located on the S2 region indicate that the major influences on the structure around the N terminus is due to the loss of the hydrogen bond between Pyr(1) and Val(95(96)) in recombinant RNases 2 and 4. We concluded the apparent steric hindrances of the extra Met to the binding pocket. As well, the affected conformational changes of active residues are attributed to the reduced activities of recombinant RNases. The structural integrity exerted by the N-terminal Pyr(1) residue may be crucial for amphibian RNases and the greatest structural differences occur on the network of the Pyr(1) residue and S2 beta-sheet region.

  15. Analysis of Inevitable Variation in C13 or HNMR Spectra Derived from One Substance for a aStructure Elucidation on the Basis of a Concept of Informational Homology

    OpenAIRE

    Kudo, Yoshihiro; Sato, Noriko; Sugai, Toshitaka

    1992-01-01

    Abstract In order to design a spectral comparison complementary with structure elucidation, actual aspects of differences among C13- or H-nmr spectra of a common compound were examined. Two handbooks, one for C13- and one for H-nmr spectra, were assumed to be data bases of the reference spectra. The handbooks were searched for common substances whose about 400 spectra were used as exercises in three books. It was confirmed that spectral variation was inevitable whenever spectral data are extr...

  16. Crystal structures and mutagenesis of PPP-family ser/thr protein phosphatases elucidate the selectivity of cantharidin and novel norcantharidin-based inhibitors of PP5C.

    Science.gov (United States)

    Chattopadhyay, Debasish; Swingle, Mark R; Salter, Edward A; Wood, Eric; D'Arcy, Brandon; Zivanov, Catherine; Abney, Kevin; Musiyenko, Alla; Rusin, Scott F; Kettenbach, Arminja; Yet, Larry; Schroeder, Chad E; Golden, Jennifer E; Dunham, Wade H; Gingras, Anne-Claude; Banerjee, Surajit; Forbes, David; Wierzbicki, Andrzej; Honkanen, Richard E

    2016-06-01

    Cantharidin is a natural toxin and an active constituent in a traditional Chinese medicine used to treat tumors. Cantharidin acts as a semi-selective inhibitor of PPP-family ser/thr protein phosphatases. Despite sharing a common catalytic mechanism and marked structural similarity with PP1C, PP2AC and PP5C, human PP4C was found to be insensitive to the inhibitory activity of cantharidin. To explore the molecular basis for this selectivity, we synthesized and tested novel C5/C6-derivatives designed from quantum-based modeling of the interactions revealed in the co-crystal structures of PP5C in complex with cantharidin. Structure-activity relationship studies and analysis of high-resolution (1.25Å) PP5C-inhibitor co-crystal structures reveal close contacts between the inhibitor bridgehead oxygen and both a catalytic metal ion and a non-catalytic phenylalanine residue, the latter of which is substituted by tryptophan in PP4C. Quantum chemistry calculations predicted that steric clashes with the bulkier tryptophan side chain in PP4C would force all cantharidin-based inhibitors into an unfavorable binding mode, disrupting the strong coordination of active site metal ions observed in the PP5C co-crystal structures, thereby rendering PP4C insensitive to the inhibitors. This prediction was confirmed by inhibition studies employing native human PP4C. Mutation of PP5C (F446W) and PP1C (F257W), to mimic the PP4C active site, resulted in markedly suppressed sensitivity to cantharidin. These observations provide insight into the structural basis for the natural selectivity of cantharidin and provide an avenue for PP4C deselection. The novel crystal structures also provide insight into interactions that provide increased selectivity of the C5/C6 modifications for PP5C versus other PPP-family phosphatases. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Elucidation of crystal and electronic structures within highly strained BiFeO3by transmission electron microscopy and first-principles simulation.

    Science.gov (United States)

    Bae, In-Tae; Kovács, András; Zhao, Hong Jian; Íñiguez, Jorge; Yasui, Shintaro; Ichinose, Tomohiro; Naganuma, Hiroshi

    2017-04-19

    Crystal and electronic structures of ~380 nm BiFeO 3 film grown on LaAlO 3 substrate are comprehensively studied using advanced transmission electron microscopy (TEM) technique combined with first-principles theory. Cross-sectional TEM images reveal the BiFeO 3 film consists of two zones with different crystal structures. While zone II turns out to have rhombohedral BiFeO 3 , the crystal structure of zone I matches none of BiFeO 3 phases reported experimentally or predicted theoretically. Detailed electron diffraction analysis combined with first-principles calculation allows us to determine that zone I displays an orthorhombic-like monoclinic structure with space group of Cm (=8). The growth mechanism and electronic structure in zone I are further discussed in comparison with those of zone II. This study is the first to provide an experimentally validated complete crystallographic detail of a highly strained BiFeO 3 that includes the lattice parameter as well as the basis atom locations in the unit cell.

  18. Structural Elucidation of the Cell-Penetrating Penetratin Peptide in Model Membranes at the Atomic Level: Probing Hydrophobic Interactions in the Blood-Brain Barrier.

    Science.gov (United States)

    Bera, Swapna; Kar, Rajiv K; Mondal, Susanta; Pahan, Kalipada; Bhunia, Anirban

    2016-09-06

    Cell-penetrating peptides (CPPs) have shown promise in nonpermeable therapeutic drug delivery, because of their ability to transport a variety of cargo molecules across the cell membranes and their noncytotoxicity. Drosophila antennapedia homeodomain-derived CPP penetratin (RQIKIWFQNRRMKWKK), being rich in positively charged residues, has been increasingly used as a potential drug carrier for various purposes. Penetratin can breach the tight endothelial network known as the blood-brain barrier (BBB), permitting treatment of several neurodegenerative maladies, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. However, a detailed structural understanding of penetratin and its mechanism of action is lacking. This study defines structural features of the penetratin-derived peptide, DK17 (DRQIKIWFQNRRMKWKK), in several model membranes and describes a membrane-induced conformational transition of the DK17 peptide in these environments. A series of biophysical experiments, including high-resolution nuclear magnetic resonance spectroscopy, provides the three-dimensional structure of DK17 in different membranes mimicking the BBB or total brain lipid extract. Molecular dynamics simulations support the experimental results showing preferential binding of DK17 to particular lipids at atomic resolution. The peptide conserves the structure of the subdomain spanning residues Ile6-Arg11, despite considerable conformational variation in different membrane models. In vivo data suggest that the wild type, not a mutated sequence, enters the central nervous system. Together, these data highlight important structural and functional attributes of DK17 that could be utilized in drug delivery for neurodegenerative disorders.

  19. Excitatory effects of thyrotropin-releasing hormone (TRH) in hypoglossal motoneurons

    DEFF Research Database (Denmark)

    Rekling, J C

    1990-01-01

    The effect of thyrotropin-releasing hormone (TRH) was studied in 30 hypoglossal motoneurons from brainstem slices of guinea pigs. Bath application of TRH resulted in an increase of the spontaneous excitatory synaptic activity, depolarization of the neurons, increase of the input resistance and ch...... and change of the duration of the falling phase of excitatory postsynaptic potentials. The depolarizing response and membrane conductance change was the result of a direct postsynaptic action of TRH, possibly mediated by a reduction of a potassium conductance....

  20. Synthesis, cloning, and identification of DNA sequences complementary to mRNAs for alpha and beta subunits of thyrotropin.

    OpenAIRE

    Vamvakopoulos, N C; Monahan, J J; Kourides, I A

    1980-01-01

    Double-stranded cDNA sequences were synthesized, by using as templates mRNA for alpha and beta subunits of thyrotropin purified from mouse thyrotrophic pituitary tumours and cloned in Escherichia coli RR1 by insertion in the Pst I site of the bacterial plasmid pBR322 by use of poly(dA) x poly(dT) homopolymeric extensions. Plasmids containing inserted cDNA sequences were selected by resistance to tetracycline and sensitivity to ampicillin; those containing thyrotropin cDNA sequences were ident...

  1. Elucidating a Key Anti-HIV-1 and Cancer-Associated Axis: The Structure of CCL5 (Rantes) in Complex with CCR5

    Science.gov (United States)

    Tamamis, Phanourios; Floudas, Christodoulos A.

    2014-06-01

    CCL5 (RANTES) is an inflammatory chemokine which binds to chemokine receptor CCR5 and induces signaling. The CCL5:CCR5 associated chemotactic signaling is of critical biological importance and is a potential HIV-1 therapeutic axis. Several studies provided growing evidence for the expression of CCL5 and CCR5 in non-hematological malignancies. Therefore, the delineation of the CCL5:CCR5 complex structure can pave the way for novel CCR5-targeted drugs. We employed a computational protocol which is primarily based on free energy calculations and molecular dynamics simulations, and report, what is to our knowledge, the first computationally derived CCL5:CCR5 complex structure which is in excellent agreement with experimental findings and clarifies the functional role of CCL5 and CCR5 residues which are associated with binding and signaling. A wealth of polar and non-polar interactions contributes to the tight CCL5:CCR5 binding. The structure of an HIV-1 gp120 V3 loop in complex with CCR5 has recently been derived through a similar computational protocol. A comparison between the CCL5 : CCR5 and the HIV-1 gp120 V3 loop : CCR5 complex structures depicts that both the chemokine and the virus primarily interact with the same CCR5 residues. The present work provides insights into the blocking mechanism of HIV-1 by CCL5.

  2. Elucidating structural order and disorder phenomena in mullite-type Al{sub 4}B{sub 2}O{sub 9} by automated electron diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haishuang; Krysiak, Yaşar [Institute of Inorganic Chemistry and Analytical Chemistry, Jakob-Welder-Weg 11, Johannes Gutenberg-University Mainz, 55128 Mainz (Germany); Hoffmann, Kristin [Crystallography, Department of Geosciences, Klagenfurter Str. 2, GEO, University of Bremen, 28359 Bremen (Germany); Institute of Inorganic Chemistry and Crystallography, Leobener Str. NW2, University of Bremen, 28359 Bremen (Germany); Barton, Bastian [Institute of Inorganic Chemistry and Analytical Chemistry, Jakob-Welder-Weg 11, Johannes Gutenberg-University Mainz, 55128 Mainz (Germany); Molina-Luna, Leopoldo [Department of Materials and Geoscience, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt (Germany); Neder, Reinhard B. [Department of Physics, Lehrstuhl für Kristallographie und Strukturphysik, Friedrich-Alexander University Erlangen-Nürnberg, Staudtstr.3, 91058 Erlangen (Germany); Kleebe, Hans-Joachim [Department of Materials and Geoscience, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt (Germany); Gesing, Thorsten M. [Institute of Inorganic Chemistry and Crystallography, Leobener Str. NW2, University of Bremen, 28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstr.1, University of Bremen, 28359 Bremen (Germany); Schneider, Hartmut [Crystallography, Department of Geosciences, Klagenfurter Str. 2, GEO, University of Bremen, 28359 Bremen (Germany); Fischer, Reinhard X. [Crystallography, Department of Geosciences, Klagenfurter Str. 2, GEO, University of Bremen, 28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstr.1, University of Bremen, 28359 Bremen (Germany); and others

    2017-05-15

    The crystal structure and disorder phenomena of Al{sub 4}B{sub 2}O{sub 9}, an aluminum borate from the mullite-type family, were studied using automated diffraction tomography (ADT), a recently established method for collection and analysis of electron diffraction data. Al{sub 4}B{sub 2}O{sub 9}, prepared by sol-gel approach, crystallizes in the monoclinic space group C2/m. The ab initio structure determination based on three-dimensional electron diffraction data from single ordered crystals reveals that edge-connected AlO{sub 6} octahedra expanding along the b axis constitute the backbone. The ordered structure (A) was confirmed by TEM and HAADF-STEM images. Furthermore, disordered crystals with diffuse scattering along the b axis are observed. Analysis of the modulation pattern implies a mean superstructure (AAB) with a threefold b axis, where B corresponds to an A layer shifted by ½a and ½c. Diffraction patterns simulated for the AAB sequence including additional stacking disorder are in good agreement with experimental electron diffraction patterns. - Graphical abstract: Crystal structure and disorder phenomena of B-rich Al{sub 4}B{sub 2}O{sub 9} studied by automated electron diffraction tomography (ADT) and described by diffraction simulation using DISCUS. - Highlights: • Ab-initio structure solution by electron diffraction from single nanocrystals. • Detected modulation corresponding mainly to three-fold superstructure. • Diffuse diffraction streaks caused by stacking faults in disordered crystals. • Observed streaks explained by simulated electron diffraction patterns.

  3. Structural elucidation of a cell wall fungal polysaccharide isolated from Ustilaginoidea virens, a pathogenic fungus of Oriza sativa and Zea mays.

    Science.gov (United States)

    Leal, J A; Jiménez-Barbero, Jesús; Bernabé, Manuel; Prieto, Alicia

    2008-11-24

    The alkali-extractable water-soluble polysaccharides (F1SS) isolated from the outer cell wall of two strains of Ustilaginoidea virens have been studied by chemical and methylation analyses, and 1D and 2D (1)H and (13)C NMR spectroscopy. The structures of these polysaccharides are very similar, and can be described by the following idealized repeating unit: where n and m are approximately 1 and 2, respectively.

  4. Structural Elucidation of cis / trans Dicaffeoylquinic Acid Photoisomerization Using Ion Mobility Spectrometry-Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Xueyun; Renslow, Ryan S.; Makola, Mpho M.; Webb, Ian K.; Deng, Liulin; Thomas, Dennis G.; Govind, Niranjan; Ibrahim, Yehia M.; Kabanda, Mwadham M.; Dubery, Ian A.; Heyman, Heino M.; Smith, Richard D.; Madala, Ntakadzeni E.; Baker, Erin S.

    2017-03-15

    Due to the recently uncovered health benefits and anti-HIV activities of dicaffeoylquinic acids (diCQAs), understanding their structures and functions is of great interest for drug discovery efforts. DiCQAs are analytically challenging to identify and quantify since they commonly exist as a diverse mixture of positional and geometric (cis/trans) isomers. In this work, we utilized ion mobility spectrometry coupled with mass spectrometry to separate the various isomers before and after UV irradiation. The experimental collision cross sections were then compared with theoretical structures to differentiate and identify the diCQA isomers. Our analyses found that naturally the diCQAs existed predominantly as trans/trans isomers, but after 3 h of UV irradiation, cis/cis, cis/trans, trans/cis, and trans/trans isomers were all present in the mixture. This is the first report of successful differentiation of cis/trans diCQA isomers individually, which shows the great promise of IMS coupled with theoretical calculations for determining the structure and activity relationships of different isomers in drug discovery studies.

  5. Structural elucidation of the predominant motifs of the major cell wall arabinogalactan antigens from the borderline species Tsukamurella paurometabolum and Mycobacterium fallax.

    Science.gov (United States)

    Tropis, Marielle; Lemassu, Anne; Vincent, Véronique; Daffé, Mamadou

    2005-07-01

    Tsukamurella paurometabolum and Mycobacterium fallax are members of the suprageneric actinomycete group Corynebacterineae that possesses a cell wall skeleton composed of a peptidoglycan to which an arabinogalactan is covalently attached. This polysaccharide is further modified by esterification with C60-C80 mycolic acid residues in mycobacteria and T. paurometabolum. However, M. fallax and T. paurometabolum produce polyenoic (up to six double bonds) mycolic acids whereas the most common type of mycobacterial mycolates, called alpha-mycolates, are mono- and di-enoic or -cyclopropanated mycolic acids. To determine whether this difference also applied to the structures of cell wall arabinogalactans, competitive inhibition experiments using antibodies raised against the cell wall from Mycobacterium bovis and the arabinogalactans from T. paurometabolum and M. fallax were performed. They demonstrated the structural identity between the polysaccharide of M. fallax and those of mycobacteria and showed a strong similarity between the latter polysaccharides and that of T. paurometabolum. Structural analyses of the per-O-alkylated alditol fragments derived from the polysaccharides by gas chromatography-mass spectrometry (GC-MS) and 13C nuclear magnetic resonance (NMR) spectroscopy of the intact solubilized polysaccharides demonstrated that the polysaccharides from the two species analyzed contained all the major structural features previously characterized in mycobacterial arabinogalactans. These include (1) the homogalactan of alterning 5-linked galactofuranosyl (Galf) and 6-linked Galf residues, (2) a linear 5-linked arabino furanosyl (Araf), (3) a beta-Araf-(1-->2)-alpha-Araf disaccharide branched on both position 3 and position 5 of an alpha-Araf unit, and (4) a 5-linked-alpha-Araf unit branched on both position 3 and position 5 of an alpha-Araf residue. The polysaccharide from T. paurometabolum possesses additional structural domains composed of a terminal (t) Araf

  6. Elucidating an Amorphous Form Stabilization Mechanism for Tenapanor Hydrochloride: Crystal Structure Analysis Using X-ray Diffraction, NMR Crystallography, and Molecular Modeling.

    Science.gov (United States)

    Nilsson Lill, Sten O; Widdifield, Cory M; Pettersen, Anna; Svensk Ankarberg, Anna; Lindkvist, Maria; Aldred, Peter; Gracin, Sandra; Shankland, Norman; Shankland, Kenneth; Schantz, Staffan; Emsley, Lyndon

    2018-03-12

    By the combined use of powder and single-crystal X-ray diffraction, solid-state NMR, and molecular modeling, the crystal structures of two systems containing the unusually large tenapanor drug molecule have been determined: the free form, ANHY, and a dihydrochloride salt form, 2HCl. Dynamic nuclear polarization (DNP) assisted solid-state NMR (SSNMR) crystallography investigations were found essential for the final assignment and were used to validate the crystal structure of ANHY. From a structural informatics analysis of ANHY and 2HCl, conformational ring differences in one part of the molecule were observed which influence the relative orientation of a methyl group on a ring nitrogen and thereby impact the crystallizability of the dihydrochloride salt. From quantum chemistry calculations, the dynamics between different ring conformations in tenapanor is predicted to be fast. Addition of HCl to tenapanor results in general in a mixture of protonated ring conformers and hence a statistical mix of diastereoisomers which builds up the amorphous form, a-2HCl. This was qualitatively verified by 13 C CP/MAS NMR investigations of the amorphous form. Thus, to form any significant amount of the crystalline material 2HCl, which originates from the minor (i.e., energetically less stable) ring conformations, one needs to involve nitrogen deprotonation to allow exchange between the minor and major conformations of ANHY in solution. Thus, by controlling the solution pH value to well below the p K a of ANHY, the equilibrium between ANHY and 2HCl can be controlled and by this mechanism the crystallization of 2HCl can be avoided and the amorphous form of the dichloride salt can therefore be stabilized.

  7. Oriented crystalline monolayers and bilayers of 2 x 2 silver(1) grid architectures at the air-solution interface: Their assembly and crystal structure elucidation

    DEFF Research Database (Denmark)

    Weissbuch, J.; Baxter, P.N.W.; Kuzmenko, I.

    2000-01-01

    Oriented crystalline monolayers, similar to 14 Angstrom thick, of a 2 x 2 Ag+ grid complex, self-assembled at the air-solution interface starting from an water-insoluble ligand 3,6-bis[2-(6-phenylpyridine)]pyridazine spread on silver-ion-containing solutions,were examined by grazing-incidence X...... by scanning force microscopy, and characterized by X-ray photoelectron spectroscopy in terms of molecular structure. On surface compression, the initial self-assembled monolayer undergoes a transition to a crystalline bilayer in which the two layers, almost retaining the original arrangement, are in registry...

  8. The isolation and structure elucidation of new cassane diterpene-acids from Caesalpinia crista L. (Fabaceae), and review on the nomenclature of some Caesalpinia species.

    Science.gov (United States)

    Kinoshita, Takeshi; Haga, Yasuhiro; Narimatsu, Shintaro; Shimada, Motoko; Goda, Yukihiro

    2005-06-01

    New cassane diterpene-acids, neocaesalpins H and I, were isolated from the leaves of Caesalpinia crista (Fabaceae), and their structures were deduced on the basis of the spectroscopic and chemical basis. These compounds were characterized as having an alpha,beta-butenolide hemiacetal ring that is rare in nature. The lacking of 5-hydroxy group also distinguished neocaesalpins H and I from cassane diterpenes (caesalpins) occurring in other Caesalpinia species from the phytochemical viewpoint. The nomenclature of three Caesalpinia species was also reviewed, and it was found that some species belonging to the genus Caesalpinia are improperly named and should be changed to valid names.

  9. Structure elucidation of phototransformation products of unapproved analogs of the erectile dysfunction drug sildenafil in artificial freshwater with UPLC-Q Exactive-MS.

    Science.gov (United States)

    Aceña, Jaume; Pérez, Sandra; Gardinali, Piero; Abad, José Luis; Eichhorn, Peter; Heuett, Nubia; Barceló, Damià

    2014-12-01

    In this study, four unapproved analogues of Sildenafil (SDF) were photodegraded under synthetic sunlight in artificial freshwater. Homosildenafil (H-SDF), hydroxyhomo-sildenafil (HH-SDF), norneosildenafil (NR-SDF) and thiosildenafil (T-SDF) were selected because they are frequently detected as adulterants in natural herbal products. Using UPLC-Orbitrap (Q Exactive)-MS, six photoproducts common to H-SDF, HH-SDF and T-SDF and nine unique transformation products of different molecular weights were identified based on their high-resolution (+)ESI product ion spectra. Mass spectral analysis of deuterated H-SDF, labeled on the N-ethyl group, allowed to gain mechanistic insight into the fragmentation pathway of the substituted piperazine ring and to support the postulated photoproduct structures. The mass spectral fragmentation confirmed the stepwise destruction of the piperazine ring eventually producing a sulfonic acid derivative (C17 H20 N4 O5 S: 392.1151 Da). In contrast, the photodegradation of NR-SDF, which lacks a piperazine ring in its structure, formed only two prominent photoproducts originating from N,N-dealkylation of the sulfonamide followed by hydrolysis. The current work constitutes the first study on the photodegradation of analogs of erectile dysfunction drugs and the first detection of two transformation products (m/z 449 and 489) in environmental samples. Copyright © 2014 John Wiley & Sons, Ltd.

  10. UV-vis degradation of α-tocopherol in a model system and in a cosmetic emulsion-Structural elucidation of photoproducts and toxicological consequences.

    Science.gov (United States)

    De Vaugelade, Ségolène; Nicol, Edith; Vujovic, Svetlana; Bourcier, Sophie; Pirnay, Stéphane; Bouchonnet, Stéphane

    2017-09-29

    The UV-vis photodegradation of α-tocopherol was investigated in a model system and in a cosmetic emulsion. Both gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) and high performance liquid chromatography coupled with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (LC-UHR-MS) were used for photoproducts structural identification. Nine photoproduct families were detected and identified based on their mass spectra and additional experiments with α-tocopherol-d 9 ; phototransformation mechanisms were postulated to rationalize their formation under irradiation. In silico QSAR (Quantitative Structure Activity Relationship) toxicity predictions were conducted with the Toxicity Estimation Software Tool (T.E.S.T.). Low oral rat LD50 values of 466.78mgkg -1 and 467.9mgkg -1 were predicted for some photoproducts, indicating a potential toxicity more than 10 times greater that of α-tocopherol (5742.54mgkg -1 ). In vitro assays on Vibrio fischeri bacteria showed that the global ecotoxicity of the α-tocopherol solution significantly increases with irradiation time. One identified product should contribute to this ecotoxicity enhancement since in silico estimations for D. magna provide a LC50 value 4 times lower than that of the parent molecule. Copyright © 2017. Published by Elsevier B.V.

  11. Facile synthesis, structure elucidation, and magnetic properties of perovskite BaTb{sub 1-x}Bi{sub x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Farid, Muhammad Asim; Zhang, Hao; Li, Guobao; Liao, Fuhui; Lin, Jianhua [Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing (China); Yang, Aimei [College of Materials Science and Engineering, Guilin University of Technology, 541004, Guilin (China); Tian, Gengfang; Wu, Meimei [Neutron Scattering Laboratory, Department of Nuclear Physics, China Institute of Atomic Energy, 102413, Beijing (China)

    2017-03-17

    A series of perovskite BaTb{sub 1-x}Bi{sub x}O{sub 3} (0.0 ≤ x ≤ 0.25) solid solutions were synthesized by a typical solid-state method. Their structures were analyzed by a combination of X-ray diffraction, neutron diffraction, and selected-area electron diffraction. All of the materials crystalize in the P1 space group [a = 6.0582(1) Aa, b = 6.0473(1) Aa, c = 6.0693(1) Aa, α = 60.00(1) , β = 59.84(1) , γ = 60.06(1) for x = 0.0 at room temperature]. Magnetic measurements revealed that the magnetic-ordering temperature decreases with increasing Bi content in BaTb{sub 1-x}Bi{sub x}O{sub 3}; therefore, the presence of Bi decreases the magnetic interactions of Tb. Furthermore, the magnetic structure for BaTb{sub 1-x}Bi{sub x}O{sub 3} has been fully described in space group P1. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Application of Molecular Techniques to Elucidate the Influence of Cellulosic Waste on the Bacterial Community Structure at a Simulated Low-Level-Radioactive-Waste Site

    International Nuclear Information System (INIS)

    Field, Erin K.; D'Imperio, Seth; Miller, Amber R.; VanEngelen, Michael R.; Gerlach, Robin; Lee, Brady D.; Apel, William A.; Peyton, Brent M.

    2010-01-01

    Low-level radioactive waste sites, including those at various U.S. Department of Energy (DOE) sites, frequently contain cellulosic waste in the form of paper towels, cardboard boxes, or wood contaminated with heavy metals and radionuclides such as chromium and uranium. To understand how the soil microbial community is influenced by the presence of cellulosic waste products, multiple soil samples were obtained from a non-radioactive model low-level waste test pit at the Idaho National Laboratory. Samples were analyzed using 16S rDNA clone libraries and 16S rRNA gene microarray (PhyloChip) analyses. Both the clone library and PhyloChip results revealed changes in the bacterial community structure with depth. In all samples, the PhyloChip detected significantly more unique Operational Taxonomic Units (OTUs), and therefore more relative diversity, than the clone libraries. Calculated diversity indices suggest that diversity is lowest in the Fill (F) and Fill Waste (FW) layers and greater in the Wood Waste (WW) and Waste Clay (WC) layers. Principal coordinates analysis and lineage specific analysis determined that Bacteroidetes and Actinobacteria phyla account for most of the significant differences observed between the layers. The decreased diversity in the FW layer and increased members of families containing known cellulose degrading microorganisms suggests the FW layer is an enrichment environment for cellulose degradation. Overall, these results suggest that the presence of the cellulosic material significantly influences the bacterial community structure in a stratified soil system.

  13. The Structure of Dasatinib (BNS-354825) Bound to Activated ABL Kinase Domain Elucidates its Inhibitory Activity Against Imatinib-Resistant ABL Mutants

    Energy Technology Data Exchange (ETDEWEB)

    Tokarski,J.; Newitt, J.; Chang, C.; Cheng, J.; Wittekind, M.; Kiefer, S.; Kish, K.; Lee, F.; Borzilerri, R.; et al.

    2006-01-01

    Chronic myeloid leukemia (CML) is caused by the constitutively activated tyrosine kinase breakpoint cluster (BCR)-ABL. Current frontline therapy for CML is imatinib, an inhibitor of BCR-ABL. Although imatinib has a high rate of clinical success in early phase CML, treatment resistance is problematic, particularly in later stages of the disease, and is frequently mediated by mutations in BCR-ABL. Dasatinib (BMS-354825) is a multitargeted tyrosine kinase inhibitor that targets oncogenic pathways and is a more potent inhibitor than imatinib against wild-type BCR-ABL. It has also shown preclinical activity against all but one of the imatinib-resistant BCR-ABL mutants tested to date. Analysis of the crystal structure of dasatinib-bound ABL kinase suggests that the increased binding affinity of dasatinib over imatinib is at least partially due to its ability to recognize multiple states of BCR-ABL. The structure also provides an explanation for the activity of dasatinib against imatinib-resistant BCR-ABL mutants.

  14. Two novel magnesium(II) meso-tetraphenylporphyrin-based coordination complexes: Syntheses, combined experimental and theoretical structures elucidation, spectroscopy, photophysical properties and antibacterial activity

    Science.gov (United States)

    Amiri, Nesrine; Hajji, Melek; Taheur, Fadia Ben; Chevreux, Sylviane; Roisnel, Thierry; Lemercier, Gilles; Nasri, Habib

    2018-02-01

    Two novel magnesium(II) tetraphenylporphyrin-based six-coordinate complexes; bis(hexamethylenetetramine)(5,10,15,2O tetrakis[4(benzoyloxy)phenyl]porphinato) magnesuim(II) (1) and bis(1,4-diazabicyclo(2.2.2)octane) (5,10,15,2O-tetrakis[4- (benzoyloxy)phenyl]porphinato)magnesium(II) (2) have been synthesised and confirmed by proton nuclear magnetic resonance, mass spectrometry, elemental analysis and IR spectroscopy. Both crystal structures were determined and described by single crystal X-ray diffraction analysis and Hirshfeld surfaces computational method. All Mg(II) atoms are surrounded by four porphyrin nitrogen atoms and two axial ligands coordinated to the metal ion through one nitrogen atom, forming a regular octahedron. In both complexes, molecular structures and three-dimensional framework are stabilised by inter-and intramolecular C-H ⋯O and C-H ⋯N hydrogen bonds, and by weak C-H ⋯Cg π interactions. UV-visible and Fluorescence investigations, respectively, show that studied complexes have a strong absorption in red part and exhibit an emission in the blue region. The HOMO-LUMO energy gap values, modelled using the DFT approach, indicates that both studied compounds can be classified as semiconductors. The role of these complexes as novel antibacterial agents was also performed.

  15. A firmer understanding of the effect of hypergravity on thyroid tissue: cholesterol and thyrotropin receptor.

    Directory of Open Access Journals (Sweden)

    Elisabetta Albi

    Full Text Available Maintaining a good health requires the maintenance of a body homeostasis which largely depends on correct functioning of thyroid gland. The cells of the thyroid tissue are strongly sensitive to hypogravity, as already proven in mice after returning to the earth from long-term space missions. Here we studied whether hypergravity may be used to counteract the physiological deconditioning of long-duration spaceflight. We investigated the influence of hypergravity on key lipids and proteins involved in thyroid tissue function. We quantified cholesterol (CHO and different species of sphingomyelin (SM and ceramide, analysed thyrotropin (TSH related molecules such as thyrotropin-receptor (TSHR, cAMP, Caveolin-1 and molecule signalling such as Signal transducer and activator of transcription-3 (STAT3. The hypergravity treatment resulted in the upregulation of the TSHR and Caveolin-1 and downregulation of STAT3 without changes of cAMP. TSHR lost its specific localization and spread throughout the cell membrane; TSH treatment facilitated the shedding of α subunit of TSHR and its releasing into the extracellular space. No specific variations were observed for each species of SM and ceramide. Importantly, the level of CHO was strongly reduced. In conclusion, hypergravity conditions induce change in CHO and TSHR of thyroid gland. The possibility that lipid rafts are strongly perturbed by hypergravity-induced CHO depletion by influencing TSH-TSHR interaction was discussed.

  16. Recombinant human thyrotropin in veterinary medicine: current use and future perspectives.

    Science.gov (United States)

    Campos, M; van Hoek, I; Peremans, K; Daminet, S

    2012-01-01

    Recombinant human thyrotropin (rhTSH) was developed after bovine thyrotropin (bTSH) was no longer commercially available. It was approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) as an aid to diagnostic follow-up of differentiated thyroid carcinoma in humans and for thyroid remnant ablation with radioiodine. In addition, rhTSH is used in human medicine to evaluate thyroid reserve capacity and to enhance radioiodine uptake in patients with metastatic thyroid cancer and multinodular goiter. Likewise, rhTSH has been used in veterinary medicine over the last decade. The most important veterinary use of rhTSH is thyroidal functional reserve testing for the diagnosis of canine hypothyroidism. Recent pilot studies performed at Ghent University in Belgium have investigated the use of rhTSH to optimize radioiodine treatment of canine thyroid carcinoma and feline hyperthyroidism. Radioiodine treatment optimization may allow a decreased therapeutic dosage of radioiodine and thus may improve radioprotection. This review outlines the current uses of rhTSH in human and veterinary medicine, emphasizing research performed in dogs and cats, as well as potential future applications. Copyright © 2012 by the American College of Veterinary Internal Medicine.

  17. Coupling multistripe laser triangulation with hyperspectral imaging VisNIR spectroscopy to elucidate the feedbacks between soil structure, hydrology, and organic matter

    Science.gov (United States)

    Hirmas, Daniel; Steffens, Markus; Sullivan, Pamela; Zhang, Chi; Giménez, Daniel

    2016-04-01

    Recent advances in three-dimensional (3-D) laser scanning techniques and reflectance spectroscopy provide the high-resolution quantitative measures needed to unravel the feedbacks mechanism between soil structure, hydrology, and organic matter at the pedon scale. Multistripe laser triangulation (MLT) can be used to quantify the shape, size, orientation, abundance, and spatial distribution of soil peds and associated macropore networks, while imaging visible light near infrared spectroscopy (imVisIR) can be used to examine the spatial distribution, quality and quantity of total, labile, and non-labile organic matter (SOM), iron, and manganese oxides at high spatial resolutions. In this work, we sought to investigate the potential for coupling these two disparate sensors (MLT and imVisIR) to examine relationships between soil structure, soil hydrology, and SOM. Soils were sampled from four landscape positions (summit, backslope, footslope, and toeslope) along an oak-hickory forest catena at the University of Kansas Field Station (KUFS) Fitch Natural History Reserve in conjunction with the installation of a National Ecological Observatory Network (NEON) site. Soil pits were excavated at each position to 1 m, described in detail by US Department of Agriculture-Natural Resource Conservation (USDA-NRCS) soil scientists, and sampled by morphological horizon for standard chemical and physical soil analyses. In addition, samples were taken from each horizon for root density and size determination, cores sampled to estimate water content, pore-size distribution, and hydraulic conductivity via low field nuclear magnetic resonance (NMR), and clods taken for water retention determination. Two intact soil monoliths per pit, carefully carved from the excavation walls at two depths (0-40 and 30-70 cm), were sampled in custom steel trays that were 15 cm wide by 40 cm long with a lip around the edge approximately 2 cm deep. The monoliths were prepared and dried at 40° C for 12

  18. Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

    Directory of Open Access Journals (Sweden)

    Elena N. Sigida

    2016-04-01

    Full Text Available An O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide isolated by the phenol–water extraction from the halotolerant soil bacteria Azospirillum halopraeferens type strain Au4. The polysaccharide was studied by sugar and methylation analyses, selective cleavages by Smith degradation and solvolysis with trifluoroacetic acid, one- and two-dimensional 1H and 13C NMR spectroscopy. The following masked repeating structure of the O-specific polysaccharide was established: →3-α-L-Rhap2Me-(1→3-[β-D-Glcp-(1→4]-α-D-Fucp-(1→2-β-D-Xylp-(1→, where non-stoichiometric substituents, an O-methyl group (~45% and a side-chain glucose residue (~65%, are shown in italics.

  19. Structure elucidation and DFT-study on substrate-selective formation of chalcones containing ferrocene and phenothiazine units. Study on ferrocenes, Part 17

    Science.gov (United States)

    Lovász, Tamás; Túrós, György; Găină, Luiza; Csámpai, Antal; Frigyes, Dávid; Fábián, Balázs; Silberg, Ioan A.; Sohár, Pál

    2005-09-01

    By means of base-catalysed condensation of 1-acyl-/1,1'-diacylferrocenes (acyl dbnd6 formyl or acetyl) with 3-formyl- and 3,7-diacetylphenothiazines a series of novel mono- and bis-chalcones were prepared. The enhanced reactivity of the enolate anions of the mono-chalcone intermediates relative to that of the enolates of the corresponding diacetyl-substituted precursor was interpreted by the electron-releasing effect of the ferrocenyl- or phenothiazinyl group present in the β position of the enone subunit. The structures of the novel products were evidenced by IR, 1H and 13C NMR spectroscopy including 2D-COSY, 2D-HSQC and 2D-HMBC measurements.

  20. Influence of the hinge region and its adjacent domains on binding and signaling patterns of the thyrotropin and follitropin receptor.

    Directory of Open Access Journals (Sweden)

    Jörg Schaarschmidt

    Full Text Available Glycoprotein hormone receptors (GPHR have a large extracellular domain (ECD divided into the leucine rich repeat (LRR domain for binding of the glycoprotein hormones and the hinge region (HinR, which connects the LRR domain with the transmembrane domain (TMD. Understanding of the activation mechanism of GPHRs is hindered by the unknown interaction of the ECD with the TMD and the structural changes upon ligand binding responsible for receptor activation. Recently, our group showed that the HinR of the thyrotropin receptor (TSHR can be replaced by those of the follitropin (FSHR and lutropin receptor (LHCGR without effects on surface expression and hTSH signaling. However, differences in binding characteristics for bovine TSH at the various HinRs were obvious. To gain further insights into the interplay between LRR domain, HinR and TMD we generated chimeras between the TSHR and FSHR. Our results obtained by the determination of cell surface expression, ligand binding and G protein activation confirm the similar characteristics of GPHR HinRs but they also demonstrate an involvement of the HinR in ligand selectivity indicated by the observed promiscuity of some chimeras. While the TSHR HinR contributes to specific binding of TSH and its variants, no such contribution is observed for FSH and its analog TR4401 at the HinR of the FSHR. Furthermore, the charge distribution at the poorly characterized LRR domain/HinR transition affected ligand binding and signaling even though this area is not in direct contact with the ligand. In addition our results also demonstrate the importance of the TMD/HinR interface. Especially the combination of the TSHR HinR with the FSHR-TMD resulted in a loss of cell surface expression of the respective chimeras. In conclusion, the HinRs of GPHRs do not only share similar characteristics but also behave as ligand specific structural and functional entities.

  1. Synthesis, structure elucidation, biological screening, molecular modeling and DNA binding of some Cu(II) chelates incorporating imines derived from amino acids

    Science.gov (United States)

    Abdel-Rahman, Laila H.; Abu-Dief, Ahmed M.; Ismael, Mohammed; Mohamed, Mounir A. A.; Hashem, Nahla Ali

    2016-01-01

    Three tridentate Schiff bases amino acids were prepared by direct condensation of 3-methoxysalicylaldehyde (MS) or 4-diethylaminosalicylaldehyde (DS) with α-amino acid ligands [L-phenylalanine (P), L-histidine (H) and DL-tryptophan (T)]. The prepared Schiff bases amino acids were investigated by melting points, elemental analysis, 1HNMR and 13CNMR, IR, UV-Vis spectra, conductivity and magnetic measurements analyses. Subsequently, copper was introduced and Cu(II) complexes formed. These complexes were analyzed by thermal and elemental analyses and further investigated by FT-IR and UV/Vis spectroscopies. The experimental results indicating that all Cu(II) complexes contain hydrated water molecules (except DSPCu complex) and don't contain coordinated water molecules. The kinetic and thermal parameters were extracted from the thermal data using Coast and Redfern method. The molar conductance values of the Schiff base amino acid ligands and their Cu(II) complexes were relatively low, showing that these compounds have non-electrolytic nature. Magnetic susceptibility measurements showed the diamagnetic nature of the Schiff base amino acid ligands and paramagnetic nature of their complexes. Additionally, a spectrophotometric method was determined to extract their stability constants. It was found that the complexes possess 1:2 (M:L) stoichiometry. The results suggested that 3-methoxysalicylaldehyde and 4-diethylaminosalicylaldehyde amino acid Schiff bases behave as monobasic tridentate ONO ligands and coordinate Cu(II) ions in octahedral geometry according to the general formula [Cu(HL)2]·nH2O. To further understanding the structural and electronic properties of these complexes, Density Functional Theory (DFT) calculations were employed and provided a satisfactory description. The optimized structures of MST Schiff base ligand and its complex were calculated using DFT. The antimicrobial activity of the Schiff base ligands and their complexes were screened against some

  2. (+)-Meyeniins A-C, Novel Hexahydroimidazo[1,5-c]thiazole Derivatives from the Tubers of Lepidium meyenii: Complete Structural Elucidation by Biomimetic Synthesis and Racemic Crystallization.

    Science.gov (United States)

    Zhou, Min; Ma, Hang-Ying; Liu, Zhi-Hua; Yang, Guang-Yu; Du, Gang; Ye, Yan-Qing; Li, Gan-Peng; Hu, Qiu-Fen

    2017-03-08

    (+)-Meyeniins A-C (1-3), a novel class of sulfur-containing hexahydroimidazo[1,5-c]thiazole derivatives, were isolated from the tubers of Lepidium meyenii (maca) cultivated in Lijiang, Yunnan province, China. Guided by their biosynthetic hypothesis, a stereocontrolled biomimetic synthesis of meyeniins A-C and their individual enantiomers was efficiently accomplished by a combination of a condensation reaction and Edman degradation. The formation of high-quality crystals for X-ray crystallography occurred much more readily from a racemic mixture of (±)-meyeniin A than with the single enantiomer alone in this case. These extensive strategies, combined with circular dichroism (CD) spectra, allowed the complete structural assignments of (+)-meyeniins A-C. Among them, (+)-meyeniin A showed moderate selective cytotoxicities against the HL-60, A549 and MCF-7 human cell lines with IC 50 values of 14.41, 32.22, and 33.14 μM, respectively. To some extent, these findings support traditional applications of maca as healthy nutritional supplements or functional foods for cancer prevention.

  3. Structural Elucidation of Poloxamer 237 and Poloxamer 237/Praziquantel Solid Dispersions: Impact of Poly(Vinylpyrrolidone) over Drug Recrystallization and Dissolution.

    Science.gov (United States)

    Orlandi, Silvina; Priotti, Josefina; Diogo, Hermínio P; Leonardi, Dario; Salomon, Claudio J; Nunes, Teresa G

    2018-01-08

    Praziquantel (PZQ) is the recommended, effective, and safe treatment against all forms of schistosomiasis. Solid dispersions (SDs) in water-soluble polymers have been reported to increase solubility and bioavailability of poorly water-soluble drugs like PZQ, generally due to the amorphous form stabilization. In this work, poloxamer (PLX) 237 and poly(vinylpyrrolidone) (PVP) K30 were evaluated as potential carriers to revert PZQ crystallization. Binary and ternary SDs were prepared by the solvent evaporation method. PZQ solubility increased similarly with PLX either as binary physical mixtures or SDs. Such unpredicted data correlated well with crystalline PZQ and PLX as detected by solid-state NMR (ssNMR) and differential scanning calorimetry in those samples. Ternary PVP/PLX/PZQ SDs showed both ssNMR broad and narrow superimposed signals, thus revealing the presence of amorphous and crystalline PZQ, respectively, and exhibited the highest PZQ dissolution efficiency (up to 82% at 180 min). SDs with PVP provided a promising way to enhance solubility and dissolution rate of PZQ since PLX alone did not prevent recrystallization of amorphous PZQ. Based on ssNMR data, novel evidences on PLX structure and molecular dynamics were also obtained. As shown for the first time using ssNMR, propylene glycol and ethylene glycol constitute the PLX amorphous and crystalline components, respectively.

  4. Crystallographic analysis of human hemoglobin elucidates the structural basis of the potent and dual antisickling activity of pyridyl derivatives of vanillin

    International Nuclear Information System (INIS)

    Abdulmalik, Osheiza; Ghatge, Mohini S.; Musayev, Faik N.; Parikh, Apurvasena; Chen, Qiukan; Yang, Jisheng; Nnamani, Ijeoma; Danso-Danquah, Richmond; Eseonu, Dorothy N.; Asakura, Toshio; Abraham, Donald J.; Venitz, Jurgen; Safo, Martin K.

    2011-01-01

    Pyridyl derivatives of vanillin increase the fraction of the more soluble oxygenated sickle hemoglobin and/or directly increase the solubility of deoxygenated sickle hemoglobin. Crystallographic analysis reveals the structural basis of the potent and dual antisickling activity of these derivatives. Vanillin has previously been studied clinically as an antisickling agent to treat sickle-cell disease. In vitro investigations with pyridyl derivatives of vanillin, including INN-312 and INN-298, showed as much as a 90-fold increase in antisickling activity compared with vanillin. The compounds preferentially bind to and modify sickle hemoglobin (Hb S) to increase the affinity of Hb for oxygen. INN-312 also led to a considerable increase in the solubility of deoxygenated Hb S under completely deoxygenated conditions. Crystallographic studies of normal human Hb with INN-312 and INN-298 showed that the compounds form Schiff-base adducts with the N-terminus of the α-subunits to constrain the liganded (or relaxed-state) Hb conformation relative to the unliganded (or tense-state) Hb conformation. Interestingly, while INN-298 binds and directs its meta-positioned pyridine-methoxy moiety (relative to the aldehyde moiety) further down the central water cavity of the protein, that of INN-312, which is ortho to the aldehyde, extends towards the surface of the protein. These studies suggest that these compounds may act to prevent sickling of SS cells by increasing the fraction of the soluble high-affinity Hb S and/or by stereospecific inhibition of deoxygenated Hb S polymerization

  5. Crystallographic analysis of human hemoglobin elucidates the structural basis of the potent and dual antisickling activity of pyridyl derivatives of vanillin

    Energy Technology Data Exchange (ETDEWEB)

    Abdulmalik, Osheiza [The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); Ghatge, Mohini S.; Musayev, Faik N.; Parikh, Apurvasena [Virginia Commonwealth University, Richmond, VA 23298 (United States); Chen, Qiukan; Yang, Jisheng [The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States); Nnamani, Ijeoma [Duke University Medical Center, Durham, NC 27710 (United States); Danso-Danquah, Richmond [Virginia Commonwealth University, Richmond, VA 23298 (United States); Eseonu, Dorothy N. [Virginia Union University, Richmond, VA 23220 (United States); Asakura, Toshio [Duke University Medical Center, Durham, NC 27710 (United States); Abraham, Donald J.; Venitz, Jurgen; Safo, Martin K., E-mail: msafo@vcu.edu [Virginia Commonwealth University, Richmond, VA 23298 (United States); The Children’s Hospital of Philadelphia, Philadelphia, PA 19104 (United States)

    2011-11-01

    Pyridyl derivatives of vanillin increase the fraction of the more soluble oxygenated sickle hemoglobin and/or directly increase the solubility of deoxygenated sickle hemoglobin. Crystallographic analysis reveals the structural basis of the potent and dual antisickling activity of these derivatives. Vanillin has previously been studied clinically as an antisickling agent to treat sickle-cell disease. In vitro investigations with pyridyl derivatives of vanillin, including INN-312 and INN-298, showed as much as a 90-fold increase in antisickling activity compared with vanillin. The compounds preferentially bind to and modify sickle hemoglobin (Hb S) to increase the affinity of Hb for oxygen. INN-312 also led to a considerable increase in the solubility of deoxygenated Hb S under completely deoxygenated conditions. Crystallographic studies of normal human Hb with INN-312 and INN-298 showed that the compounds form Schiff-base adducts with the N-terminus of the α-subunits to constrain the liganded (or relaxed-state) Hb conformation relative to the unliganded (or tense-state) Hb conformation. Interestingly, while INN-298 binds and directs its meta-positioned pyridine-methoxy moiety (relative to the aldehyde moiety) further down the central water cavity of the protein, that of INN-312, which is ortho to the aldehyde, extends towards the surface of the protein. These studies suggest that these compounds may act to prevent sickling of SS cells by increasing the fraction of the soluble high-affinity Hb S and/or by stereospecific inhibition of deoxygenated Hb S polymerization.

  6. Purification, crystallization and structural elucidation of D-galactaro-1,4-lactone cycloisomerase from Agrobacterium tumefaciens involved in pectin degradation.

    Science.gov (United States)

    Vetting, Matthew W; Bouvier, Jason T; Gerlt, John A; Almo, Steven C

    2016-01-01

    Pectin is found in the cell wall of plants and is often discarded as waste. A number of research groups are interested in redirecting this biomass waste stream for the production of fuel and bulk chemicals. The primary monomeric subunit of this polysaccharide is D-galacturonate, a six-carbon acid sugar that is degraded in a five-step pathway to central metabolic intermediates by some bacteria, including Agrobacterium tumefaciens. In the third step of the pathway, D-galactaro-1,4-lactone is converted to 2-keto-3-deoxy-L-threo-hexarate by a member of the mandelate racemase subgroup of the enolase superfamily with a novel activity for the superfamily. The 1.6 Å resolution structure of this enzyme was determined, revealing an overall modified (β/α)7β TIM-barrel domain, a hallmark of the superfamily. D-Galactaro-1,4-lactone was manually docked into the active site located at the interface between the N-terminal lid domain and the C-terminal barrel domain. On the basis of the position of the lactone in the active site, Lys166 is predicted to be the active-site base responsible for abstraction of the α proton. His296 on the opposite side of the active site is predicted to be the general acid that donates a proton to the β carbon as the lactone ring opens. The lactone ring appears to be oriented within the active site by stacking interactions with Trp298.

  7. Crystal structure and mutagenesis of a protein phosphatase-1:calcineurin hybrid elucidate the role of the beta12-beta13 loop in inhibitor binding.

    Science.gov (United States)

    Maynes, Jason T; Perreault, Kathleen R; Cherney, Maia M; Luu, Hue Anh; James, Michael N G; Holmes, Charles F B

    2004-10-08

    Protein phosphatase-1 and protein phosphatase-2B (calcineurin) are eukaryotic serine/threonine phosphatases that share 40% sequence identity in their catalytic subunits. Despite the similarities in sequence, these phosphatases are widely divergent when it comes to inhibition by natural product toxins, such as microcystin-LR and okadaic acid. The most prominent region of non-conserved sequence between these phosphatases corresponds to the beta12-beta13 loop of protein phosphatase-1, and the L7 loop of toxin-resistant calcineurin. In the present study, mutagenesis of residues 273-277 of the beta12-beta13 loop of the protein phosphatase-1 catalytic subunit (PP-1c) to the corresponding residues in calcineurin (312-316), resulted in a chimeric mutant that showed a decrease in sensitivity to microcystin-LR, okadaic acid, and the endogenous PP-1c inhibitor protein inhibitor-2. A crystal structure of the chimeric mutant in complex with okadaic acid was determined to 2.0-A resolution. The beta12-beta13 loop region of the mutant superimposes closely with that of wild-type PP-1c bound to okadaic acid. Systematic mutation of each residue in the beta12-beta13 loop of PP-1c showed that a single amino acid change (C273L) was the most influential in mediating sensitivity of PP-1c to toxins. Taken together, these data indicate that it is an individual amino acid residue substitution and not a change in the overall beta12-beta13 loop conformation of protein phosphatase-1 that contributes to disrupting important interactions with inhibitors such as microcystin-LR and okadaic acid.

  8. Synthesis, structural elucidation, microbial, antioxidant and nuclease activities of some novel divalent M(II complexes derived from 5-fluorouracil and l-tyrosine

    Directory of Open Access Journals (Sweden)

    Jeyaprakash Dharmaraja

    2017-01-01

    Full Text Available Novel N2O2 sequence of mononuclear amino acid metal(II complexes (1a–1e was synthesized from 5-fluorouracil (5-FU: A and l-tyrosine (tyr: B with Mn(II, Co(II, Ni(II, Cu(II and Zn(II ions. The synthesized complexes were structurally characterized by analytical, spectral (FT-IR, UV–vis, 1H NMR, FAB-Mass, TGA/DTA and EPR as well as molar conductance and magnetic studies. From spectral studies, both the ligands act as bidentate and they bind metal(II ions through deprotonated-N3 and C4O atoms and amino-N and deprotonated carboxylato-O atoms, respectively, to form a stable metal chelate. The observed low molar conductance values suggest a non-electrolytic nature. Calculated g tensor values of Cu(II complex (1d at 77 and 300 K confirm their geometry. Thermal behavior of metal(II complexes (1a–1c shows loss of coordinated water molecules in the first step followed by decomposition of ligand moieties in a respective manner and leads to form air stable metal oxide as final residues. Powder X-ray diffraction and SEM studies illustrate that all the complexes have uniform microcrystalline with homogenous morphology. Mn(II, Ni(II and Cu(II complexes show significant in vitro antimicrobial and antioxidant activities than 5-fluorouracil(A. Moreover, the nuclease studies of Ni(II and Cu(II complexes (1c and 1d show considerable DNA binding and oxidative DNA cleavage activities than other complexes.

  9. Motuporamines, anti-invasion and anti-angiogenic alkaloids from the marine sponge Xestospongia exigua (Kirkpatrick): isolation, structure elucidation, analogue synthesis, and conformational analysis.

    Science.gov (United States)

    Williams, David E; Craig, Kyle S; Patrick, Brian; McHardy, Lianne M; van Soest, Rob; Roberge, Michel; Andersen, Raymond J

    2002-01-11

    Extracts of the sponge Xestospongia exigua collected in Papua New Guinea were positive in a new assay for anti-invasion activity. Bioassay-guided fractionation led to the identification of the three known motuporamines A (1), B (2), and C (3) along with the new motuporamines D (4), E (5), and F (6) and a mixture of G, H, and I (15). Motuporamines A (1), B (2), and C (3) and the mixture of G, H, and I (15) were responsible for the anti-invasion activity of the crude extract. Motuporamine C (3) has also been found to be anti-angiogenic. A series of analogues of the motuporamines have been synthesized and evaluated for anti-invasive activity. These SAR results revealed that a saturated 15-membered cyclic amine fused to the natural motuporamine diamine side chain (13) represented the optimal structure for anti-invasive activity in this family. Single-crystal X-ray diffraction analysis of one of the analogues 20 showed that in the solid state its 16-membered macrocyclic amine fragment adopted the [4444] quadrangular conformation predicted by calculations to be the lowest energy conformation for the corresponding cycloalkane, cyclohexadecane. These data along with literature X-ray data and conformational analysis for derivatives of azacyclotridecane have been used as precedents for predicting the lowest energy ring conformations of other motuporamines. The SAR data from the natural and synthetic motuporamines have been combined with the conformational analyses to provide an outline of the functionality and shape required for activity in this family of alkaloids and to design a new analogue 49 that showed good anti-invasion activity.

  10. NR4A1 (Nur77 mediates thyrotropin-releasing hormone-induced stimulation of transcription of the thyrotropin β gene: analysis of TRH knockout mice.

    Directory of Open Access Journals (Sweden)

    Yasuyo Nakajima

    Full Text Available Thyrotropin-releasing hormone (TRH is a major stimulator of thyrotropin-stimulating hormone (TSH synthesis in the anterior pituitary, though precisely how TRH stimulates the TSHβ gene remains unclear. Analysis of TRH-deficient mice differing in thyroid hormone status demonstrated that TRH was critical for the basal activity and responsiveness to thyroid hormone of the TSHβ gene. cDNA microarray and K-means cluster analyses with pituitaries from wild-type mice, TRH-deficient mice and TRH-deficient mice with thyroid hormone replacement revealed that the largest and most consistent decrease in expression in the absence of TRH and on supplementation with thyroid hormone was shown by the TSHβ gene, and the NR4A1 gene belonged to the same cluster as and showed a similar expression profile to the TSHβ gene. Immunohistochemical analysis demonstrated that NR4A1 was expressed not only in ACTH- and FSH- producing cells but also in thyrotrophs and the expression was remarkably reduced in TRH-deficient pituitary. Furthermore, experiments in vitro demonstrated that incubation with TRH in GH4C1 cells increased the endogenous NR4A1 mRNA level by approximately 50-fold within one hour, and this stimulation was inhibited by inhibitors for PKC and ERK1/2. Western blot analysis confirmed that TRH increased NR4A1 expression within 2 h. A series of deletions of the promoter demonstrated that the region between bp -138 and +37 of the TSHβ gene was responsible for the TRH-induced stimulation, and Chip analysis revealed that NR4A1 was recruited to this region. Conversely, knockdown of NR4A1 by siRNA led to a significant reduction in TRH-induced TSHβ promoter activity. Furthermore, TRH stimulated NR4A1 promoter activity through the TRH receptor. These findings demonstrated that 1 TRH is a highly specific regulator of the TSHβ gene, and 2 TRH mediated induction of the TSHβ gene, at least in part by sequential stimulation of the NR4A1-TSHβ genes through a PKC and

  11. Structure Elucidation of New Acetylated Saponins, Lessoniosides A, B, C, D, and E, and Non-Acetylated Saponins, Lessoniosides F and G, from the Viscera of the Sea Cucumber Holothuria lessoni

    Directory of Open Access Journals (Sweden)

    Yadollah Bahrami

    2015-01-01

    Full Text Available Sea cucumbers produce numerous compounds with a wide range of chemical structural diversity. Among these, saponins are the most diverse and include sulfated, non-sulfated, acetylated and methylated congeners with different aglycone and sugar moieties. In this study, MALDI and ESI tandem mass spectrometry, in the positive ion mode, were used to elucidate the structure of new saponins extracted from the viscera of H. lessoni. Fragmentation of the aglycone provided structural information on the presence of the acetyl group. The presence of the O-acetyl group was confirmed by observing the mass transition of 60 u corresponding to the loss of a molecule of acetic acid. Ion fingerprints from the glycosidic cleavage provided information on the mass of the aglycone (core, and the sequence and type of monosaccharides that constitute the sugar moiety. The tandem mass spectra of the saponin precursor ions [M + Na]+ provided a wealth of detailed structural information on the glycosidic bond cleavages. As a result, and in conjunction with existing literature, we characterized the structure of five new acetylated saponins, Lessoniosides A–E, along with two non-acetylated saponins Lessoniosides F and G at m/z 1477.7, which are promising candidates for future drug development. The presented strategy allows a rapid, reliable and complete analysis of native saponins.

  12. Elucidating the structural properties that influence the persistence of PCBs in humans using the National Health and Nutrition Examination Survey (NHANES) dataset

    Energy Technology Data Exchange (ETDEWEB)

    Megson, David, E-mail: dpmegson@hotmail.co.uk [Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA (United Kingdom); O’Sullivan, Gwen [Department of Environmental Science, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, Alberta, T3E 6K6 (Canada); Comber, Sean; Worsfold, Paul J.; Lohan, Maeve C. [Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA (United Kingdom); Edwards, Melanie R.; Shields, Walter J. [Exponent Inc., 15375 Southeast 30th Place, Bellevue, WA 98007 (United States); Sandau, Courtney D. [Chemistry Matters Inc., 2120 1st Avenue NW, Calgary, Alberta T2N 0B5 (Canada); Patterson, Donald G. [Exponent Inc., One Capital City Plaza, Suite 1620, 3350 Peachtree Road, Atlanta, GA 30326 (United States)

    2013-09-01

    In human exposure studies involving Polychlorinated Biphenyls (PCBs), it is useful to establish when an individual was potentially exposed. Age dating PCB exposure is complex but assessments can be made because different PCB congeners have different residence times in the human body. The less chlorinated congeners generally tend to have shorter residence times because they are biotransformed and eliminated faster than more chlorinated congeners. Therefore, the presence of high proportions of less chlorinated congeners is often indicative of recent exposure. The 2003–04 National Health and Nutrition Examination Survey (NHANES) dataset contains results for the concentration of 37 PCBs in a sub-sample of the US population. Multivariate statistical analysis of the NHANES data showed that less chlorinated congeners are not always biotransformed faster than higher chlorinated compounds. For example, PCB 28 (a tri-chlorobiphenyl) appears to be more resistant to biotransformation than PCB 101 and 110 (penta-chlorobiphenyls). Using statistical analysis of the NHANES data in conjunction with previously published studies on PCB persistence in humans, it was possible to identify the structural relationships that determine if a PCB is likely to be from a recent exposure (termed ‘episodic’) or from steady state exposure. Congeners with chlorine atoms in the 2,5- and 2,3,6-positions appear to be more susceptible to biotransformation whereas congeners with chlorine bonds in the 2,3,4- 2,4,5- 3,4,5- and 2,3,4,5-positions appear to be more persistent. This work shows that future investigations to date PCB exposure would benefit from the analysis of a wide range of congeners, including the selection of key congeners based not only on the degree of chlorination but also on the positions of the chlorine atoms on the biphenyl. - Highlights: • NHANES data was used to compare the PCB signature of different aged participants. • PCB residence time may be explained by the number

  13. Elucidating the structural properties that influence the persistence of PCBs in humans using the National Health and Nutrition Examination Survey (NHANES) dataset

    International Nuclear Information System (INIS)

    Megson, David; O’Sullivan, Gwen; Comber, Sean; Worsfold, Paul J.; Lohan, Maeve C.; Edwards, Melanie R.; Shields, Walter J.; Sandau, Courtney D.; Patterson, Donald G.

    2013-01-01

    In human exposure studies involving Polychlorinated Biphenyls (PCBs), it is useful to establish when an individual was potentially exposed. Age dating PCB exposure is complex but assessments can be made because different PCB congeners have different residence times in the human body. The less chlorinated congeners generally tend to have shorter residence times because they are biotransformed and eliminated faster than more chlorinated congeners. Therefore, the presence of high proportions of less chlorinated congeners is often indicative of recent exposure. The 2003–04 National Health and Nutrition Examination Survey (NHANES) dataset contains results for the concentration of 37 PCBs in a sub-sample of the US population. Multivariate statistical analysis of the NHANES data showed that less chlorinated congeners are not always biotransformed faster than higher chlorinated compounds. For example, PCB 28 (a tri-chlorobiphenyl) appears to be more resistant to biotransformation than PCB 101 and 110 (penta-chlorobiphenyls). Using statistical analysis of the NHANES data in conjunction with previously published studies on PCB persistence in humans, it was possible to identify the structural relationships that determine if a PCB is likely to be from a recent exposure (termed ‘episodic’) or from steady state exposure. Congeners with chlorine atoms in the 2,5- and 2,3,6-positions appear to be more susceptible to biotransformation whereas congeners with chlorine bonds in the 2,3,4- 2,4,5- 3,4,5- and 2,3,4,5-positions appear to be more persistent. This work shows that future investigations to date PCB exposure would benefit from the analysis of a wide range of congeners, including the selection of key congeners based not only on the degree of chlorination but also on the positions of the chlorine atoms on the biphenyl. - Highlights: • NHANES data was used to compare the PCB signature of different aged participants. • PCB residence time may be explained by the number

  14. Determination of thyrotropin reference values in an adult Mexican population.

    Science.gov (United States)

    Flores-Rebollar, Armando; Moreno-Castañeda, Lidia; Vega-Servín, Norman S; López-Carrasco, Guadalupe; Ruiz-Juvera, Aída

    2015-02-01

    The upper limit of TSH reference level is controversial. The purpose of our study was to determine TSH reference values in a Mexican population in accordance with the National Academy of Clinical Biochemistry (NACB) criteria and in correlation with thyroid ultrasound (US) examination. The study was conducted in volunteers with no known thyroid disease. We recruited 482 subjects, most of them medical or administrative staff from our hospital. They answered a questionnaire on demographic data, family history, co-morbidities, and drug use. Their thyroid hormone levels and thyroid antibodies were determined, and a complete physical examination and thyroid US were performed. The population used to establish the TSH reference intervals was selected according to the NACB criteria and their normal thyroid structural and echogenic characteristics in US examination. Among 482 subjects (209 males) with a median age of 26 years, prevalence rates of TPOAb and TgAb were 9.3% and 10.3% respectively. Mean TSH level in the overall population was 1.90±1.94, with a 97.5th percentile of 6.76 mIU/L. The reference population was limited to 282 subjects (41.5% were excluded) with a mean TSH of 1.86±1.63 and a 97.5th percentile of 4.88 mIU/L. No sex difference was found (p=0.287). Median urinary iodine level in the reference population was 267 μg/L IQR (161.3-482.5). The TSH reference interval in the reference population was 0.71 (CI 0.65-0.77) to 4.88 mIU/L (CI 4.5-5.3); these limits may be influenced by iodine nutritional status in this population. Copyright © 2014 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

  15. Gene expression of thyrotropin- and corticotrophin-releasing hormones is regulated by environmental salinity in the euryhaline teleost Sparus aurata.

    Science.gov (United States)

    Ruiz-Jarabo, Ignacio; Martos-Sitcha, J A; Barragán-Méndez, C; Martínez-Rodríguez, G; Mancera, J M; Arjona, F J

    2018-04-01

    In euryhaline teleosts, the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-interrenal axes (HPT and HPI, respectively) are regulated in response to environmental stimuli such as salinity changes. However, the molecular players participating in this physiological process in the gilthead seabream (Sparus aurata), a species of high value for aquaculture, are still not identified and/or fully characterized in terms of gene expression regulation. In this sense, this study identifies and isolates the thyrotropin-releasing hormone (trh) mRNA sequence from S. aurata, encoding prepro-Trh, the putative factor initiating the HPT cascade. In addition, the regulation of trh expression and of key brain genes in the HPI axis, i.e., corticotrophin-releasing hormone (crh) and corticotrophin-releasing hormone-binding protein (crhbp), was studied when the osmoregulatory status of S. aurata was challenged by exposure to different salinities. The deduced amino acid structure of trh showed 65-81% identity with its teleostean orthologs. Analysis of the tissue distribution of gene expression showed that trh mRNA is, though ubiquitously expressed, mainly found in brain. Subsequently, regulation of gene expression of trh, crh, and crhbp was characterized in fish acclimated to 5-, 15-, 40-, and 55-ppt salinities. In this regard, the brain gene expression pattern of trh mRNA was similar to that found for the crh gene, showing an upregulation of gene expression in seabream acclimated to the highest salinity tested. Conversely, crhbp did not change in any of the groups tested. Our results suggest that Trh and Crh play an important role in the acclimation of S. aurata to hypersaline environments.

  16. Elucidating the structure-property relationships of donor-π-acceptor dyes for dye-sensitized solar cells (DSSCs) through rapid library synthesis by a one-pot procedure.

    Science.gov (United States)

    Fuse, Shinichiro; Sugiyama, Sakae; Maitani, Masato M; Wada, Yuji; Ogomi, Yuhei; Hayase, Shuzi; Katoh, Ryuzi; Kaiho, Tatsuo; Takahashi, Takashi

    2014-08-18

    The creation of organic dyes with excellent high power conversion efficiency (PCE) is important for the further improvement of dye-sensitized solar cells. We wish to describe the rapid synthesis of a 112-membered donor-π-acceptor dye library by a one-pot procedure, evaluation of PCEs, and elucidation of structure-property relationships. No obvious correlations between ε, and the η were observed, whereas the HOMO and LUMO levels of the dyes were critical for η. The dyes with a more positive E(HOMO), and with an E(LUMO)dyes; nevertheless, that was not sufficient for identifying the best combination of donor, π, and acceptor blocks. Combinatorial synthesis and evaluation was important for identifying the best dye. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. High-pressure synthesis and single-crystal structure elucidation of the indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Ortner, Teresa S.; Vitzthum, Daniela; Heymann, Gunter; Huppertz, Hubert [Department of General, Inorganic and Theoretical Chemistry, Centre of Chemistry and Biomedicine (CCB), Leopold-Franzens-University Innsbruck (Austria)

    2017-12-29

    The indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7} was synthesized under high-pressure/high-temperature conditions at 12.5 GPa/1420 K using a Walker-type multianvil apparatus. Single-crystal X-ray structure elucidation showed edge-sharing OIn{sub 4} tetrahedra and B{sub 2}O{sub 7} units building up the oxide-borate. It crystallizes with Z = 8 in the monoclinic space group P2{sub 1}/n (no. 14) with a = 1016.54(3), b = 964.55(3), c = 1382.66(4) pm, and β = 109.7(1) . The compound was also characterized by powder X-ray diffraction and vibrational spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Quality characteristics of chemicals for the radioimmunoassay of thyroxine and thyrotropin

    International Nuclear Information System (INIS)

    Verdeja I, C.E.

    1994-01-01

    Radioimmunoassay is a form of saturation analysis in which the test material competes with labelled antigen for a limited amount of antibody, the amount of label displaced being a measure of the antigen in the test sample. In this country, the kits for Radioimmunoassay (RIA) are imported, and this increase the cost of it. Because this lack of production, the National Institute of Nuclear Research (ININ) has developed RIA's kits for the thyroxine (T 4 ), Thyrotropin (TSH) and Triyodotironine (T 3 ) hormones. This work presents the conclusions of the test recommended by the WHO. The quality test were: recuperation, cross reactions, basic parameters, intra and inter assay variations, sensibility and others. The results show that the RIA's kits of the ININ have a good behavior and can be use in the clinical laboratory. (Author)

  19. The 24-hour profiles of thyrotropin, throxine and triiodothyronine in goitrous and goitre-free Ugandans

    International Nuclear Information System (INIS)

    Kajubi, S.K.

    1980-01-01

    Plasma thyrotropin (TSH), thyroxine (T4) and triiodothyronine (T3) concentrations were measured by radioimmunoassay with commercial assay kits in serial blood samples collected over a 24-hour period from 6 normal and 6 clinically euthyroid but goitrous male Ugandan subjects. Measurements on normal subjects revealed two peaks in plasma TSH concentration, one at about 08.00 hrs, the other at about 20.00 hrs. Plasma T4 concentrations showed two corresponding peaks, while plasma T3 concentrations showed no discernable pattern. Measurement on goitrous subjects revealed only the earlier peak in plasma TSH concentration, while the pooled mean TSH concentration was lower than in normal subjects. Plasma T4 concentrations showed two peaks, as for normal subjects, but the pooled mean T4 concentration was also lower than in normal subjects. Measurements on plasma T3 concentration again showed no discernable pattern. The significance of these findings is discussed

  20. Thyroxine and thyrotropin radioimmunoassays using dried blood samples on filter paper for screening of neonatal hypothyroidism

    International Nuclear Information System (INIS)

    Beckers, C.; Cornette, C.; Francois, B.; Bouckaert, A.; Lechat, M.

    1977-01-01

    A routine and automatized methodology for thyroxine (T4) and thyrotropin (TSH) radioimmunoassay (RIA) using dried blood samples on filter paper is described. Five mm diameter dots were prepared. One eluted dot, corresponding to 4 μl of plasma, was used for T4-RIA while two were necessary for TSH-RIA. Reference filter papers were introduced in each assay for quality control. In a preliminary study on 1903 newborns, samples were obtained, generally between the 5th-7th day. Mean dot T4 was 7.38 +- 2.5 μg/dl. Mean dot TSH was 11.83 +- 9.1 μU/ml, the equation of the regression line between dot TSH (y) and serum TSH (x) being Y = 10.29 + 0.623x. (orig.) [de

  1. Response to thyrotropin-releasing hormone stimulation tests in preterm infants with transient hypothyroxinemia of prematurity.

    Science.gov (United States)

    Yamamoto, A; Kawai, M; Iwanaga, K; Matsukura, T; Niwa, F; Hasegawa, T; Heike, T

    2015-09-01

    Whether hormone supplementation is necessary for infants with transient hypothyroxinemia of prematurity (THOP) remains controversial, and further analysis of the hypothalamus-pituitary-thyroid axis of infants with THOP is necessary. Thyrotropin-releasing hormone (TRH) stimulation tests were performed at 2 weeks of age in 50 infants with a gestational age of 30 weeks or less, and the data were analyzed retrospectively. Subjects were divided into three groups; group A consisted of euthyroid infants, group B consisted of infants with THOP and group C consisted of hypothyroid infants. The basal and peak thyroid-stimulating hormone level of group C in response to TRH stimulation tests was significantly higher than the others, but no differences were observed between groups A and B. The response of infants with THOP to the TRH stimulation test was not different from that of euthyroid infants, which suggested that their hypothalamic-pituitary-thyroid axis was appropriately regulated in infants with THOP.

  2. The role of thyrotropin suppression in patients with differentiated thyroid carcinoma.

    LENUS (Irish Health Repository)

    Deasy, J

    2010-07-01

    Thyroid carcinoma is the commonest endocrine malignancy. The majority of these are differentiated thyroid carcinomas, which have a good overall prognosis. Treatment includes surgical excision, radio-iodine ablation and long-term thyrotropin suppression. The degree and length of suppression required, as well as the potential side-effect remain controversial. Therefore, the aim of this study was to establish the degree of thyrotropin suppression achieved in a cohort of patients with differentiated thyroid carcinoma. A retrospective review was performed of a prospectively maintained database. All patients with a diagnosis of differentiated thyroid carcinoma between January 1998 and January 2008 were identified. Demographic data, pathological stage and the treatment that the patient received was documented. TSH and free T4 levels were identified at specific time points post-operatively. Eighty-eight patients with differentiated thyroid carcinoma were identified. Seventy patients (79.5%) were female. The mean age was 55, with a range of 18 to 79 years. The majority of patients underwent a total thyroidectomy (n=79; 89.7%) and of those 29 (32.9%) had an associated modified neck dissection. Accurate follow-up was available on forty-nine patients. TSH and free T4 were measured at 3 and 6 months, as well as at 1 and 2 years post-operatively. Adequate TSH suppression was taken at a level < 0.1 mU\\/L. The majority of patients (69.5%) had achieved adequate TSH suppression at 2 years. However, 65% of these same patients had a high free T4 at 2 years indicating a degree of hyperthyroidism. This study has demonstrated that TSH suppression is being adequately achieved in the majority of patients with differentiated thyroid carcinoma. However, this must be carefully weighed against the potential detrimental side-effects of long-term sub-clinical hyperthyroidism.

  3. Signaling-sensitive amino acids surround the allosteric ligand binding site of the thyrotropin receptor.

    Science.gov (United States)

    Kleinau, Gunnar; Haas, Ann-Karin; Neumann, Susanne; Worth, Catherine L; Hoyer, Inna; Furkert, Jens; Rutz, Claudia; Gershengorn, Marvin C; Schülein, Ralf; Krause, Gerd

    2010-07-01

    The thyrotropin receptor [thyroid-stimulating hormone receptor (TSHR)], a G-protein-coupled receptor (GPCR), is endogenously activated by thyrotropin, which binds to the extracellular region of the receptor. We previously identified a low-molecular-weight (LMW) agonist of the TSHR and predicted its allosteric binding pocket within the receptor's transmembrane domain. Because binding of the LMW agonist probably disrupts interactions or leads to formation of new interactions among amino acid residues surrounding the pocket, we tested whether mutation of residues at these positions would lead to constitutive signaling activity. Guided by molecular modeling, we performed site-directed mutagenesis of 24 amino acids in this spatial region, followed by functional characterization of the mutant receptors in terms of expression and signaling, measured as cAMP accumulation. We found that mutations V421I, Y466A, T501A, L587V, M637C, M637W, S641A, Y643F, L645V, and Y667A located in several helices exhibit constitutive activity. Of note is mutation M637W at position 6.48 in transmembrane helix 6, which has a significant effect on the interaction of the receptor with the LMW agonist. In summary, we found that a high proportion of residues in several helices surrounding the allosteric binding site of LMW ligands in the TSHR when mutated lead to constitutively active receptors. Our findings of signaling-sensitive residues in this region of the transmembrane bundle may be of general importance as this domain appears to be evolutionarily retained among GPCRs.

  4. Evaluation of the responsiveness of pituitary gland to thyrotropin releasing hormone (TRH) in rats in the period of 8:00 to 12:00 a.m

    International Nuclear Information System (INIS)

    Borghi, V.C.; Nicolau, W.; Bojarczuk, C.; Pieroni, R.R.

    1977-01-01

    The functional pituitary capacity for the secretion thyrotropin in rats, in relation to the period of time 8:00-12:00 a.m. was studied by means of the administration of synthetic TRH (thyrotropin releasing hormone). The highest pituitary response to the hypothalamic hormone attains its peak between 9:50 and 10:30 a.m., a time in which the gland denotes a high and practically constant level of TSH secretion [pt

  5. Ultrahigh-performance liquid chromatography-ion trap mass spectrometry characterization of the steroidal saponins of Dioscorea panthaica Prain et Burkill and its application for accelerating the isolation and structural elucidation of steroidal saponins.

    Science.gov (United States)

    Wang, Weihao; Zhao, Ye; Jing, Wenguang; Zhang, Jun; Xiao, Hui; Zha, Qin; Liu, An

    2015-03-01

    Dioscorea panthaica is a traditional Chinese medicinal herb used in the treatment of various physiological conditions, including cardiovascular disease, gastropathy and hypertension. Steroidal saponins (SS) are the main active ingredients of this herb and have effects on myocardial ischemia and cancer. The phytochemical evaluation of SS is both time-consuming and laborious, and the isolation and structural determination steps can be especially demanding. For this reason, the development of new methods to accelerate the processes involved in the identification, isolation and structural elucidation of SS is highly desirable. In this study, a new ultrahigh performance liquid chromatography-ion trap mass spectrometry (UHPLC-IT/MS(n)) method has been developed for the identification of the SS in D. panthaica Prain et Burkill. Notably, the current method can distinguish between spirostanol and furostanol-type compounds based on the fragmentation patterns observed by electrospray ionization-ion trap mass spectrometry (ESI-IT/MS(n)) analysis. UHPLC-IT/MS(n) was used to conduct a detailed investigation of the number, structural class and order of the sugar moieties in the sugar chains of the SS present in D. panthaica. The established fragmentation features were used to analyze the compounds found in the 65% ethanol fraction of the water extracts of D. panthaica. Twenty-three SS were identified, including 11 potential new compounds and six groups of isomers. Two of these newly identified SS were selected as representative examples, and their chemical structures were confirmed by (1)H and (13)C NMR analyses. This newly developed UHPLC-IT/MS(n) method therefore allowed for the efficient identification, isolation and structural determination of the SS in D. panthaica. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Further elucidation of the genomic structure of PAX3, and identification of two different point mutations within the PAX3 homeobox that cause Waardenburg syndrome type I in two families

    Energy Technology Data Exchange (ETDEWEB)

    Lalwani, A.K.; Brister, J.R.; Fex, J.; Grundfast, K.M.; Ploplis, B.; San Agustin, T.B.; Wilcox, E.R. [National Institute on Deafness and Other Communication Disorders, Bethesda, MD (United States)

    1995-01-01

    Waardenburg syndrome is an autosomal dominant disorder characterized by sensorineural deafness and pigmentary disturbances. Previous work has linked the disease to PAX3 on chromosome 2, and several mutations within the highly conserved paired-box and octapeptide motifs, but not the homeobox, have been reported. In this report, we have used the published cDNA sequence to further define the genomic structure of PAX3, using inverse PCR. We have identified exon/intron boundaries between exons 5 and 6 and between exons 6 and 7. Further, we have identified the first two mutations within the homeobox in two different families with type 1 Waardenburg syndrome. The first is a point mutation (G{yields}T) at the first base of exon 6, which substitutes phenylalanine for valine. In another family, we have identified a point mutation (C{yields}G) within the homeobox, in exon 6, which substitutes a glycine for arginine at a highly conserved site. The homeodomain is important in binding of DNA and in effecting transcriptional control. These mutations likely result in structural change within the homeodomain that either change the DNA-binding specificity of the homeodomain or reduce the affinity of the PAX3 protein for DNA. These homeodomain mutations should aid in elucidating the role of the homeodomain in the function of the PAX3 protein. 46 refs., 5 figs., 2 tabs.

  7. Structure elucidation of the diagnostic product ion at m/z 97 derived from androst-4-en-3-one-based steroids by ESI-CID and IRMPD spectroscopy.

    Science.gov (United States)

    Thevis, Mario; Beuck, Simon; Höppner, Sebastian; Thomas, Andreas; Held, Joseph; Schäfer, Mathias; Oomens, Jos; Schänzer, Wilhelm

    2012-03-01

    Structure elucidation of steroids by mass spectrometry has been of great importance to various analytical arenas and numerous studies were conducted to provide evidence for the composition and origin of (tandem) mass spectrometry-derived product ions used to characterize and identify steroidal substances. The common product ion at m/z 97 generated from androst-4-ene-3-one analogs has been subject of various studies, including stable isotope-labeling and (high resolution/high accuracy) tandem mass spectrometry, but its gas-phase structure has never been confirmed. Using high resolution/high accuracy mass spectrometry and low resolution tandem mass spectrometry, density functional theory (DFT) calculation, and infrared multiple photon dissociation (IRMPD) spectroscopy employing a free electron laser, the structure of m/z 97 derived from testosterone was assigned to protonated 3-methyl-2-cyclopenten-1-one. This ion was identified in a set of six cyclic C(6)H(9)O(+) isomers as computed at the B3LYP/6-311++G(2d,2p) level of theory (protonated 3-methyl-2-cyclopenten-1-one, 2-methyl-2-cyclopenten-1-one and 2-cyclohexen-1-one). Product ions of m/z 97 obtained from MS(2) and MS(3) experiments of protonated 3-methyl-2-cyclopenten-1-one, 2-methyl-2-cyclopenten-1-one, 2-cyclohexen-1-one, and testosterone corroborated the suggested gas-phase ion structure, which was eventually substantiated by IRMPD spectroscopy yielding a spectrum that convincingly matched the predicted counterpart. Finally, the dissociation pathway of the protonated molecule of testosterone to m/z 97 was revisited and an alternative pathway was suggested that considers the exclusion of C-10 along with the inclusion of C-5, which was experimentally demonstrated with stable isotope labeling.

  8. Spectral, structural elucidation and coordination abilities of Co(II) and Mn(II) coordination entities of 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzenacyclooctadecaphan-8,17-diene

    Science.gov (United States)

    Rajiv, Kumar; Rajni, Johar

    2011-09-01

    Designing tactics were tailored and followed by synthetic and formulation methodologies to prepare 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzenacyclooctadecaphan-8,17-diene. Spectral techniques (MS, infrared, 1H NMR, 13C NMR, electronic and EPR), physiochemical measurements (elemental analysis, molar conductance and magnetic susceptibility), electrochemistry (cyclic voltammetry) and classical mechanics (molecular modeling) were employed for structural elucidation of Co(II) and Mn(II) coordination entities having N 2O 4 chromophore. Comparative spectral analysis revealed legating nature of N 2O 4 donor macrocycle and confirmed host/guest connectivity between ligand and metal(s). Mass spectrometry (MS) determined 1:1 stoichiometry in CEs. Further electrochemical study confirmed change in oxidation and reduction patterns of CEs. Inhibiting potential (antifungal screened against Aspergillus flavus) showed enhanced antimicrobial properties of CEs as compared to ligand. Molecular modeling was employed to find out different molecular features along with their stabilization energies.

  9. Thyrotropin receptor and CD40 mediate interleukin-8 expression in fibrocytes: implications for thyroid-associated ophthalmopathy (an American Ophthalmological Society thesis).

    Science.gov (United States)

    Douglas, Raymond S; Mester, Tünde; Ginter, Anna; Kim, Denise S

    2014-01-01

    To better understand the pathogenesis of thyroid-associated orbitopathy (TAO) through elucidating the role of thyrotropin receptor (TSHR) and CD40 in the expression of interleukin-8 (IL-8) in peripheral blood fibrocytes. Fibrocytes infiltrate the orbit of patients with TAO, where they differentiate into fibroblasts. Fibrocyte precursors occur with increased frequency in the peripheral blood expressing TSHR and CD40 in TAO patients. We hypothesize that in vitro derived fibrocytes and peripheral blood fibrocyte precursors express proinflammatory chemoattractant molecules including IL-8 initiated by TSHR and CD40 signaling. Since nearly all TAO patients express activating antibodies to TSHR, this is particularly relevant for activation of peripheral blood fibrocytes. TSHR and CD40 expression on peripheral blood fibrocytes was determined by flow cytometry. IL-8 RNA was quantitated by real-time polymerase chain reaction. IL-8 protein production was measured by Luminex and flow cytometry. Thyroid-stimulating hormone and CD40 ligand-stimulated phosphorylation of Akt in peripheral blood fibrocytes was studied by flow cytometry. Both TSHR- and CD40-mediated signaling lead to IL-8 expression in mature fibrocytes. Fibrocyte precursors assayed directly from circulating peripheral blood demonstrate intracellular IL-8 expression with addition of thyroid-stimulating hormone or CD40 ligand. TSHR- and CD40-induced IL-8 production is mediated by Akt phosphorylation. Peripheral blood TSHR(+) and CD40(+) fibrocytes express IL-8 and may promote the recruitment of inflammatory cells, mitogenesis, and tissue remodeling in TAO. TSHR- and CD40-mediated IL-8 signaling is mediated by Akt. Delineating the molecular mechanisms of fibrocyte immune function may provide potential therapeutic targets for TAO.

  10. Impact of renal function and demographic/anthropomorphic variables on peak thyrotropin after recombinant human thyrotropin stimulation: a stepwise forward multiple-regression analysis.

    Science.gov (United States)

    Hautzel, Hubertus; Pisar, Elisabeth; Lindner, David; Schott, Matthias; Grandt, Rüdiger; Müller, Hans-Wilhelm

    2013-06-01

    When applying the recommended standard doses of recombinant human thyrotropin (rhTSH) in the diagnostic/therapeutic management of patients with differentiated thyroid cancer (DTC), the resulting peak TSH levels vary extensively. Previous studies applying multivariate statistics identified patient-inherent variables influencing the rhTSH/peak TSH relation. However, those results were inconclusive and partly conflicting. Notably, no independent role of renal function was substantiated, despite the fact that the kidneys are known to play a prominent role in TSH clearance from blood. Therefore, the study's aim was to investigate the impact of renal function on the peak TSH concentration after the standard administration of rhTSH used in the management of thyroid cancer. The second objective was to calculate a ranking regarding the effect sizes of the selected variables on the peak TSH. There were 286 patients with DTC included in the study. Univariate and multivariate analyses were performed, testing the correlation of serum creatinine and glomerular filtration rate (GFR) as surrogate parameters of renal function, age, sex, weight, height, and body surface area (BSA) with the peak TSH level. In six additional patients, the subsequent TSH pharmacokinetics after the TSH peak were measured and qualitatively compared. By univariate analyses, TSH correlated negatively with BSA, GFR, weight, and height, and positively with age, female sex, and serum creatinine (prenal function as the two most influential independent variables, followed by age, sex, and height. The pharmacokinetic datasets indicated that these identified parameters also influence the TSH decline over time. Identifying those patients with a favorable combination of parameters predicting a high-peak TSH is the first step toward an individualization of rhTSH dosing. Additionally, the subsequent TSH decrease over time needs to be taken into account. A complete understanding of the interrelation of the identified

  11. Structural elucidation of AgAsS2 glass by the analysis of clusters formed during laser desorption ionisation applying quadrupole ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Mawale, Ravi Madhukar; Alberti, Milan; Zhang, Bo; Fraenkl, Max; Wagner, Tomas; Havel, Josef

    2016-03-15

    The structure of AgA(s)S2 glass, which has a broad range of applications, is still not well understood and a systematic mass spectrometric analysis of AgA(s)S2 glass is currently not available. Elucidation of the structure should help in the development of this material. The AgA(s)S2 glass was prepared by the melt-quenched technique. Laser desorption ionisation (LDI) using quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to follow the generation of Ag(m)As(n)S(x) clusters. The stoichiometry of the clusters generated was determined via collision-induced dissociation (CID) and modelling of isotopic patterns. The AgA(s)S2 glass was characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. The LDI of AgA(s)S2 glass leads to the formation of unary (Ag+/− and As(3+)) species, 38 binary (As(n)S(x), Ag(m)S(x)), and 98 ternary (Ag(m)As(n)S(x)) singly charged clusters. The formation of silver-rich nano-grains during AgA(s)S2 glass synthesis has been identified using TEM analysis and also verified by QIT-TOFMS. TOFMS was shown to be a useful technique to study the generation of Ag(m)As(n)S(x )clusters. SEM, TEM and EDX analysis proved that the structure of AgA(s)S2 glass is ‘grain-like’ where grains are either: (1) Silver-rich ‘islands’ (Ag(m,) m up to 39) connected by arsenic and/or sulfur or arsenic sulfide chains or (2) silver sulfide (Ag2S)m (m = 9-20) clusters also similarly inter-connected. This obtained structural information may be useful for the development of ultra-high-density phase-change storage and memory devices using this kind of glass as a base.

  12. Role of thyrotropin-releasing hormone in prolactin-producing cell models.

    Science.gov (United States)

    Kanasaki, Haruhiko; Oride, Aki; Mijiddorj, Tselmeg; Kyo, Satoru

    2015-12-01

    Thyrotropin-releasing hormone (TRH) is a hypothalamic hypophysiotropic neuropeptide that was named for its ability to stimulate the release of thyroid-stimulating hormone in mammals. It later became apparent that it exerts a number of species-dependent hypophysiotropic activities that regulate other pituitary hormones. TRH also regulates the synthesis and release of prolactin, although whether it is a physiological regulator of prolactin that remains unclear. Occupation of the Gq protein-coupled TRH receptor in the prolactin-producing lactotroph increases the turnover of inositol, which in turn activates the protein kinase C pathway and the release of Ca(2+) from storage sites. TRH-induced signaling events also include the activation of extracellular signal-regulated kinase (ERK) and induction of MAP kinase phosphatase, an inactivator of activated ERK. TRH stimulates prolactin synthesis through the activation of ERK, whereas prolactin release occurs via elevation of intracellular Ca(2+). We have been investigating the role of TRH in a pituitary prolactin-producing cell model. Rat pituitary somatolactotroph GH3 cells, which produce and release both prolactin and growth hormone (GH), are widely used as a model for the study of prolactin- and GH-secreting cells. In this review, we describe the general action of TRH as a hypophysiotropic factor in vertebrates and focus on the role of TRH in prolactin synthesis using GH3 cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Thyrotropin-releasing hormone (TRH promotes wound re-epithelialisation in frog and human skin.

    Directory of Open Access Journals (Sweden)

    Natalia T Meier

    Full Text Available There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression. Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters.

  14. Spinal cord thyrotropin releasing hormone receptors of morphine tolerant-dependent and abstinent rats

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, N.H.; Gulati, A.; Bhargava, H.N. (Univ. of Illinois, Chicago (USA))

    1990-07-01

    The effect of chronic administration of morphine and its withdrawal on the binding of 3H-(3-MeHis2)thyrotropin releasing hormone (3H-MeTRH) to membranes of the spinal cord of the rat was determined. Male Sprague-Dawley rats were implanted with either 6 placebo or 6 morphine pellets (each containing 75-mg morphine base) during a 7-day period. Two sets of animals were used. In one, the pellets were left intact at the time of sacrificing (tolerant-dependent) and in the other, the pellets were removed 16 hours prior to sacrificing (abstinent rats). In placebo-pellet-implanted rats, 3H-MeTRH bound to the spinal cord membranes at a single high affinity binding site with a Bmax of 21.3 +/- 1.6 fmol/mg protein, and an apparent dissociation constant Kd of 4.7 +/- 0.8 nM. In morphine tolerant-dependent or abstinent rats, the binding constants of 3H-MeTRH to spinal cord membranes were unaffected. Previous studies from this laboratory indicate that TRH can inhibit morphine tolerance-dependence and abstinence processes without modifying brain TRH receptors. Together with the present results, it appears that the inhibitory effect of TRH on morphine tolerance-dependence and abstinence is probably not mediated via central TRH receptors but may be due to its interaction with other neurotransmitter systems.

  15. Thyrotropin-releasing hormone receptor binding sites: autoradiographic distribution in the rat and guinea pig brain

    Energy Technology Data Exchange (ETDEWEB)

    Pazos, A.; Cortes, R.; Palacios, J.M.

    1985-11-01

    Thyrotropin-releasing hormone (TRH) binding sites were labeled in vitro in mounted brain tissue sections from rat and guinea pig brains with (TH)methyl TRH and localized autoradiographically using TH-sensitive film. Regional densities of TRH binding sites were measured by computer-assisted microdensitometry. The distribution of sites in both species was highly heterogeneous. In both guinea pig and rat brains, the highest densities of binding sites were seen in the amygdaloid nuclei and the perirhinal cortex. In contrast, in other brain areas, a clear difference between the distribution of sites in rat and guinea pig was found. The temporal cortex, pontine nuclei, and interpeduncular nucleus, which contained high densities of binding in the guinea pig, were scarcely labeled in the rat. The accessory olfactory bulb and the septohippocampal area presented in the rat higher concentrations of binding sites than in the guinea pig. The anterior pituitary also presented low to intermediate concentrations of receptors. The distribution of TRH sites here described does not completely correlate with that of endogenous TRH, but is in good agreement with previous biochemical data. The results are discussed in correlation to the physiological effects that appear to be mediated by TRH.

  16. Thyrotropin receptor autoantibodies and early miscarriages in patients with Hashimoto thyroiditis: a case-control study.

    Science.gov (United States)

    Toulis, Konstantinos A; Goulis, Dimitrios G; Tsolakidou, Konstantina; Hilidis, Ilias; Fragkos, Marios; Polyzos, Stergios A; Gerofotis, Antonios; Kita, Marina; Bili, Helen; Vavilis, Dimitrios; Daniilidis, Michail; Tarlatzis, Basil C; Papadimas, Ioannis

    2013-08-01

    We have previously hypothesized that early miscarriage in women with Hashimoto thyroiditis might be the result of a cross-reactivity process, in which blocking autoantibodies against thyrotropin receptor (TSHr-Ab) antagonize hCG action on its receptor on the corpus luteum. To test this hypothesis from the clinical perspective, we investigated the presence of TSHr-Ab in Hashimoto thyroiditis patients with apparently unexplained, first-trimester recurrent miscarriages compared to that in Hashimoto thyroiditis patients with documented normal fertility. A total of 86 subjects (43 cases and 43 age-matched controls) were finally included in a case-control study. No difference in the prevalence of TSHr-Ab positivity was detected between cases and controls (Fisher's exact test, p value = 1.00). In patients with recurrent miscarriages, TSHr-Ab concentrations did not predict the number of miscarriages (univariate linear regression, p value = 0.08). These results were robust in sensitivity analyses, including only cases with full investigation or those with three or more miscarriages. We conclude that no role could be advocated for TSHr-Ab in the aetiology of recurrent miscarriages in women with Hashimoto thyroiditis.

  17. Autoradiographic localization of thyrotropin releasing hormone (TRH) receptors in the central nervous system

    International Nuclear Information System (INIS)

    Manaker, S.

    1985-01-01

    Quantitative autoradiography was used to examine the distribution of thyrotropin-releasing hormone (TRH) receptors in the rat and human central nervous system (CNS). The binding of [ 3 H]-3-methyl-histidine 2 -TRH ([ 3 H]-MeTRH) to TRH receptors was saturable, of a high affinity (K/sub d/ = 5 nM), and specific for TRH analogs. Studies with neurotoxins ibotenic acid and 6-hydroxydopamine (6-OHDA) suggest that TRH receptors within the amygdala are predominantly located on cell bodies, and not nerve terminals. Finally, an examination was made of the concentrations of TRH receptors in spinal cords of patients with amyotrophic lateral sclerosis (ALS), a degenerative disease of the motor neurons located in Lamina IX. Large decreases in TRH receptors were noted in ALS spinal cords, when compared to non-neurological controls, probably reflecting the loss of motor neurons. In addition, decreases in the TRH receptor concentration of Lamina II were observed. This finding may reflect the sensitivity of neurons throughout the CNS to the pathophysiologic mechanisms of neuronal degeneration which cause ALS

  18. Spectral analysis, structural elucidation and evaluation of chemical reactivity of synthesized ethyl-4-[(2-cyano-acetyl)-hydrazonomethyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate through experimental studies and quantum chemical calculations

    Science.gov (United States)

    Rawat, P.; Singh, R. N.

    2014-09-01

    This paper describes the synthesis, spectral analysis, structural elucidation and chemical reactivity of pyrrole hydrazide-hydrazone: ethyl-4-[(2-cyano-acetyl)-hydrazonomethyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate (ECAHDPC). The 1H, 13C NMR isotropic chemical shifts and electronic absorption spectra have been calculated by GIAO and TD-DFT methods, respectively, and corroborate well with experimental data. The NH proton of the hydrazide-hydrazones (lbond2 Cdbnd NNHCO) frame appears as singlet at δ = 11.69 ppm due to delocalization of nitrogen lone pair with carbonyl group and its proton involvement in intramolecular H-bonding. The calculated wavenumbers of dimer are in good agreement with the experimental results and confirm that the stable conformer forms dimer by hydrogen bonding interactions between pyrrolic NH and carbonyl Cdbnd O group of ester giving red shift and resonance assisted hydrogen bonding. The binding energy of intermolecular interaction is found to be 10.19 kcal/mol after basis set superposition error correction. QTAIM calculations confirm the existence of intermolecular conventional hydrogen bond (Nsbnd H⋯O), intra and intermolecular non-conventional hydrogen bond (Csbnd H⋯O) and intramolecular interaction (C⋯N). The NBO analysis has been performed to evaluate charge transfer and delocalization of electron density. The static first hyperpolarizability (β0) of monomer has been found to be 6.59 × 10-30 esu. The maximum value of reactivity descriptors (fk+, sk+, ωk+) at C(9) indicate that this site is more susceptible to nucleophilic attack, favoring for the formation of heterocyclic compounds.

  19. Structural elucidation of the nonclassical secondary cell wall polysaccharide from Bacillus cereus ATCC 10987. Comparison with the polysaccharides from Bacillus anthracis and B. cereus type strain ATCC 14579 reveals both unique and common structural features.

    Science.gov (United States)

    Leoff, Christine; Choudhury, Biswa; Saile, Elke; Quinn, Conrad P; Carlson, Russell W; Kannenberg, Elmar L

    2008-10-31

    Nonclassical secondary cell wall polysaccharides constitute a major cell wall structure in the Bacillus cereus group of bacteria. The structure of the secondary cell wall polysaccharide from Bacillus cereus ATCC 10987, a strain that is closely related to Bacillus anthracis, was determined. This polysaccharide was released from the cell wall with aqueous hydrogen fluoride (HF) and purified by gel filtration chromatography. The purified polysaccharide, HF-PS, was characterized by glycosyl composition and linkage analyses, mass spectrometry, and one- and two-dimensional NMR analysis. The results showed that the B. cereus ATCC 10987 HF-PS has a repeating oligosaccharide consisting of a -->6)-alpha-GalNAc-(1-->4)-beta-ManNAc-(1-->4)-beta-GlcNAc-(1--> trisaccharide that is substituted with beta-Gal at O3 of the alpha-GalNAc residue and nonstoichiometrically acetylated at O3 of the N-acetylmannosamine (ManNAc) residue. Comparison of this structure with that of the B. anthracis HF-PS and with structural data obtained for the HF-PS from B. cereus type strain ATCC 14579 revealed that each HF-PS had the same general structural theme consisting of three HexNAc and one Hex residues. A common structural feature in the HF-PSs from B. cereus ATCC 10987 and B. anthracis was the presence of a repeating unit consisting of a HexNAc(3) trisaccharide backbone in which two of the three HexNAc residues are GlcNAc and ManNAc and the third can be either GlcNAc or GalNAc. The implications of these results with regard to the possible functions of the HF-PSs are discussed.

  20. Standardization of human thyrotropin radioimmunoassay and its application to the purification of this hormone to the preparation of the assay reagents

    International Nuclear Information System (INIS)

    Lin, L.H.

    1991-01-01

    The various steps that are necessary for setting up the thyrotropin radioimmunoassay are presented below. Radioiodination was carried out through the Chloramine T method and the labeled purification performed on Sephadex G-100. Purification of human thyrotropin from side fractions obtained during the purification of growth hormone was carried out in order to obtain a pure reagent for use in the radioimmunoassay. The employment of the hormone obtained was evaluated as the radioimmunoassay tracer in comparison with that prepared from the hormone received from the NIDDKD, U.S.A. The results indicated that although it was not possible to obtain a hormone with a purity degree adequate to be used as the tracer, enough experience was acquired for the isolation of thyrotropin. (author)

  1. Thyrotropin - Binding Inhibiting Immunoglobulin (TBII) in Patients with Autoimmune Thyroid Diseases

    International Nuclear Information System (INIS)

    Jang, Dae Sung; Ahn, Byeong Cheol; Sohn, Sang Kyun; Lee, Jae Tae; Lee, Kyu Bo

    1996-01-01

    In order to evaluate the significance of thyrotropin-binding inhibiting immunoglobulin (TBII) in the patients with autoimmune thyroid diseases, the authors investigated 402 cases of Graves' disease and 230 cases of Hashimoto's thyroiditis comparing 30 cases of normal healthy adult at Kyung Pook University Hospital from February 1993 to August 1994. The TBII was tested by radioimmunoassay and assessed on the dynamic change with the disease course, thyroid functional parameters, and other thyroid autoantibodies; antithyroglobulin antibody(ATAb) and antimicrosomal antibody(AMAb) including thyroglobulin. The serum level of TBII was 40.82 ± 21.651(mean ± SD)% in hyperthyroid Graves' disease and 8.89 ± 14.522% in Hashimoto's thyroiditis and both were significant different from normal control of which was 3.21 ± 2.571%. The frequency of abnormally increased TBII level was 92.2% in hyperthyroid Craves' disease, 46.7% in euthyroid Graves' disease or remission state of hyperthyroidism, and 23.9% in Hashimoto's thyroiditis. The serum levels of increased TBII in Graves' disease were positively correlated with RAIU, serum T3, T4, and FT4, but negatively correlated with serum TSH(each p<0.001). The TBII in Graves' disease had significant positive correlation with serum thyroglobulin and AMAb, but no significant correlation with ATAb. In the Hashimoto's thyroiditis, the serum levels of TBII were positively correlated with RAIU, serum T3, TSH and AMAb, but not significantly correlated with serum T4, FT4, thyroglobulin and ATAb. Therefore serum level of TBII seemed to be a useful mean of assessing the degree of hyperthyroidism in Graves' disease and correlated well with thyroidal stimulation. The serum level of TBII in Hashimoto's thyroiditis is meaningful for the degree of both functional abnormality reflecting either hyperfunction or hypofunction and the immunologic abnormality.

  2. Inhibition of thyrotropin response to TSH-releasing hormone by thyroxine in hypothyroid rats

    Energy Technology Data Exchange (ETDEWEB)

    Boado, R.J.; Zaninovich, A.A.; Ulloa, E.R.; Fernandez Pol, J.A.

    1985-05-01

    Pharmacological amounts of throxine (T4) can inhibit the thyrotropin (TSH) response to TSH-releasing hormone (TRH) before its conversion to triiodothyronine (T3) in the hypophysis of euthyroid rate. The present work tested physiological doses of T4 in hypothyroid rats. Rats were treated with iopanoic acid (IOP) 5 mg/100 g BW 24, 12 and 1.5 hours preceding the study, to prevent intrapituitary conversion of T4 to T3. Nonradioactive T4 was injected iv at time 0. At 20 min a 1 ..mu..g/100 g BW dose of TRH was injected iv. Blood samples were drawn at times 0, 20, and 30 min for determination by radioimmunoassay of plasma T4, T3, and TSH. In untreated rats basal TSH was 1450 +- 200 (SEM) ..mu..U/ml. At 20 min it was 105 +- 12% the basal value and at 30 min (10 min post-TRH) plasma TSH rose to 165 +- 14%. In T4-treated rats, those injected with IOP or with the vehicle alone both had the TSH response suppressed. IOP reduced intrapitutiary T3 from 4.6 +- 2.4 to 0.5 +- 0.2 fmol/min/gland. Thirty min. following the iv injection of 150 ..mu..Ci of double-labeled /sup 125/I-T4, the in vitro cytoplasmic radioactivity in control rats was 1.3 +- 0.13 x 10-/sup 2/% of the injected dose (75% T4, 17% T3), while in nuclei it was 4.2 +- 3.6 x 10-/sup 3/% (5l% T4, 28% T3). The injection of 25 ..mu..g of nonradioactive T4 decreased /sup 125/I-T4 in cytoplasm with no changes in nuclei. These findings suggest an intrinsic capacity of T4 to control TRH stimulation of TSH through binding to cytoplasmic receptors.

  3. Brain receptors for thyrotropin releasing hormone in morphine tolerant-dependent rats

    Energy Technology Data Exchange (ETDEWEB)

    Bhargava, H.N.; Das, S.

    1986-03-01

    The effect of chronic treatment of rats with morphine and its subsequent withdrawal on the brain receptors for thyrotropin releasing hormone (TRH) labeled with /sup 3/H-(3MeHis/sup 2/)TRH (MeTRH). Male Sprague Dawley rats were implanted with 4 morphine pellets (each containing 75 mg morphine base) during a 3-day period. Placebo pellet implanted rats served as controls. Both tolerance to and dependence on morphine developed as a result of this procedure. For characterization of brain TRH receptors, the animals were sacrificed 72 h after the implantation of first pellet. In another set of animals the pellets were removed and were sacrificed 24 h later. The binding of /sup 3/H-MeTRH to membranes prepared from brain without the cerebellum was determined. /sup 3/H-MeTRH bound to brain membranes prepared from placebo pellet implanted rats at a single high affinity site with a B/sub max/ value of 33.50 +/- 0.97 fmol/mg protein and a K/sub d/ of 5.18 +/- 0.21 nM. Implantation of morphine pellets did not alter the B/sub max/ value of /sup 3/H-MeTRH but decreased the K/sub d/ value significantly. Abrupt or naloxone precipitated withdrawal of morphine did not alter B/sub max/ or the K/sub d/ values. The binding of /sup 3/H-MeTRH to brain areas was also determined. The results suggest that the development of tolerance to morphine is associated with enhanced sensitivity of brain TRH receptors, however abrupt withdrawal of morphine does not change the characteristics of brain TRH receptors.

  4. Determination of congenital hypothyroidism in neonatal by immunoradiometric assays of thyrotropin

    International Nuclear Information System (INIS)

    Contreras P, E.

    1998-01-01

    The congenital hypothyroidism is the endocrine illness more frequent of the childhood, it is the one that produce the devastating effects on the growth and the development. It represent one of the few causes of mental delay that it could be prevented if it is diagnosed and treaty on time. The infants affected with congenital hypothyroidism, could be detected for the apparent presence of some physical abnormalities, which comes the first days of the birth. Unfortunately, in the moment in which the classical manifestations are made present, it is very probable that cerebral damage already exists, for what the affected children should be tried before the three months of life administering them thyroid hormones. In Mexico the incidence of the congenital hypothyroidism is of one for each 1612 births for that is very important in the area of Public Health diagnose in early form and with certainty the congenital hypothyroidism. The TSH hormone or thyrotropin is formed in the hypophysis and intervenes in the synthesis of the thyroid hormones (T3, T4) when the concentration of these is adapted, the formation of TSH is inhibited, for that upon lacking the thyroid hormones the concentration of TSH in the blood is high. For these reasons the shot metabolic state of a newborn could be determined, quantifying the TSH in blood obtained by heel stab of the neonatal, or in coming blood from the umbilical cord, after 48 hours of being born. However because the TSH is similar to other hormones and is in extremely low concentrations, it is made necessary appeal analytic techniques of very sensitive and specific laboratory like the Immunoradiometric assays (Irma) in order to could determine the levels of this hormone in the blood. (Author)

  5. Phosphoinositides metabolism in primary culture of dog thyroid cells: Effects of thyrotropin and carbachol

    International Nuclear Information System (INIS)

    Taguchi, M.; Field, J.B.

    1990-01-01

    Thyrotropin (TSH) and carbachol stimulated in a dose-dependent manner the accumulation of 3H-glycerophosphoinositol (GPI), 3H-inositol monophosphate (IP1), 3H-inositol bisphosphate (IP2) and 3H-inositol trisphosphate (IP3) in primary cultures of dog thyroid cells prelabeled with myo-[2-3H]inositol. TSH, 250 mU/mL, stimulated 3H-IP3 level after a 10-minute incubation while 10 mU/mL TSH increased it during a 60-minute incubation. The effect of carbachol was more rapid and greater than that of TSH. Carbachol, 100 mumol/L, elevated 3H-IP3 after a 2-minute incubation and 3H-IP3 formation was increased by as little as 1 mumol/L carbachol. TSH stimulation was observed only if the cells were deprived of TSH for 5 days before being labeled with 3H-inositol. Prolongation of the labeling period or addition of TSH, (Bu)2cAMP or carbachol during the labeling increased 3H-inositol incorporation into polyphoinositides (PIPs). When the cells were labeled without any other addition, control and TSH-stimulated 3H-IP3 levels increased in parallel with 3H-PIP levels. However, TSH or carbachol-stimulated 3H-IP3 levels did not increase in proportion to 3H-PIPs level when the cells were labeled with TSH or (Bu)2cAMP. Thus, the ratio of 3H-IP3/3H-PIPs (both control and TSH or carbachol-stimulated) decreased in the cells labeled with TSH or (Bu)2cAMP, which might reflect TSH stimulation of 3H-inositol incorporation into PIPs pool(s) that do not participate in hormone-induced hydrolysis of PIPs

  6. Effects of Thyrotropin-Releasing Hormone (TRH) on the Actions of Pentobarbital and Other Centrally Acting Drugs1

    Science.gov (United States)

    Breese, George R.; Cott, Jerry M.; Cooper, Barrett R.; Prange, Arthur J.; Lipton, Morris A.; Plotnikoff, Nicholas P.

    2010-01-01

    Thyrotropin-releasing hormone (TRH) was found to antagonize pentobarbital-induced sleeping time and hypothermia. While 3 to 100 mg/kg of TRH reduced pentobarbital sleeping time when administered prior to the barbiturate, a dose-response relationship to TRH could not be established. However, doses of 10 to 100 mg/kg of TRH enhanced the lethality of pentobarbital when these compounds were administered simultaneously. Thyrotropin or l-triiodothyronine did not imitate and hypophysectomy did not reduce the effects of TRH, indicating that the pituitary is not essential for its antagonism of pentobarbital Studies of TRH analogs provided further support of this view In addition TRH reduced the sleep and hypothermia produced by thiopental amobarbital, seco-barbital and phenobarbital, and it antagonized the hypothermia and reduced motor activity produced by chloral hydrate, reserpine, chlorpromazine and diazepam Intracisternally administered TRH also reduced pentobarbital sleeping time and hypothermia but melanocyte-stimulating hormone release-inhibiting factor and somatostatin administered by this route did not While reduction of pentobarbital sleeping time by TRH could not be attributed to an affect on monoamine systems or to deamidated TRH, this action was reduced by intracisternally administered atropine suggesting that cholinergic mechanisms may contribute to the effects of TRH. Thus the results provide evidence that TRH acts on brain independent of an effect on the pituitary. PMID:805836

  7. [Thyrotropin reference ranges during pregnancy in the province of Huelva, Spain].

    Science.gov (United States)

    Ortega Carpio, A; Vázquez Rico, I; Castaño López, M A; Duarte González, L; Montilla Álvaro, M; Ruiz Reina, A

    2017-11-18

    The correct diagnosis of hypothyroidism during pregnancy requires knowledge of the local trimester-specific thyrotropin (TSH) reference ranges. When these are not available, the guidelines recommend upper limits of 2.5, 3.0, and 3.0μU/ml for the 1 st , 2 nd , and 3 rd trimesters, respectively. The aim is to establish the reference range for our local population. A population-based observational study was performed on healthy pregnant women from 11 healthcare centres in the province of Huelva. Women were recruited consecutively during 2016 through the pregnancy process. Women were excluded who had a history of thyroid or medical disease, a poor obstetric history, multiple pregnancy, thyroid autoimmunity, and extreme TSH values (10μU/ml), as well as women treated with levothyroxine for thyroid dysfunction. The study included a total of 186 pregnant women, with a mean age of 30.7 years (95% CI: 29.8-31.6) and a body mass index (BMI) of 23.6 (95% CI: 23.2-24.0). Most of them had the first laboratory tests performed before week 11 of pregnancy. Valid subjects for analysis were 145, 105, and 67 pregnant women in the 1 st , 2 nd , and 3 rd trimesters, respectively, after excluding those due to abortion (18.9%), autoimmunity (6.5%), hypo/hyperthyroidism (2.2%), and levothyroxine treatment during the 2 nd /3 rd trimester (18.6%). The 97.5% TSH percentile for the 1 st , 2 nd , and 3 rd trimester was 4.68, 4.83, and 4.57μU/ml, respectively. Thyroid dysfunction was identified in 80 women (55.2%), 33 of whom received treatment with Levothyroxine (22.7%). With the new criteria, thyroid dysfunction prevalence would be reduced to 6.2%, and the need for treatment to 4.1%. The reference range for TSH in our population differs from that proposed by the guidelines. Unnecessary treatment was being given to 18.6% of pregnant women. Copyright © 2017 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

  8. Thyrotropin-releasing hormone (TRH) receptors. Localization by light microscopic autoradiography in rat brain using [3H][3-Me-His2]TRH as the radioligand

    International Nuclear Information System (INIS)

    Mantyh, P.W.; Hunt, S.P.

    1985-01-01

    Thyrotropin releasing hormone (TRH) is a putative neurotransmitter in both the central and peripheral nervous system. In the present report, we have used autoradiography coupled with densitometric analysis of tritium-sensitive film to investigate the distribution of [ 3 H][3-Me-His2]TRH [( 3 H]MeTRH)-binding sizes in the rat brain. Previous pharmacological reports have established that many of these [ 3 H]MeTRH-binding sites have a structure-activity profile consistent with being a physiological TRH receptor. A high level of TRH receptors were observed in the accessory olfactory bulb, lateral nucleus of the amygdala, dentate gyrus, and entorhinal cortex. Moderate levels of TRH receptors were observed in the rhinal cortex, hypothalamus, superior colliculus, several brainstem motor nuclei, and lamina I of the spinal trigeminal nucleus pars candalis, while low concentrations of receptors are present in the cerebral cortex, striatum and ventral horn of the spinal cord. Very low levels of receptors were observed in the globus pallidus and in most nuclei of the dorsal thalamus. Comparisons of the distribution of TRH receptors to TRH-immunoreactive content indicates that, while in some areas of the brain there is a rough correlation between levels of TRH peptide and its receptor, in most brain areas there is little obvious correlation between the two. While such a discrepancy has been observed for other peptides and their receptors, the extensive distribution of TRH receptors in the central nervous system does provide an explanation for the variety of behavioral effects observed when TRH is infused into the central nervous system

  9. Basal levels of triiodotironine, thyroxine, thyrotropin, free thyroxine and reverse triiodotyronine in patients with chronic renal failure submitted to hemodialysis

    International Nuclear Information System (INIS)

    Knobel, H.; Mendonca, B.B. de; Mendes, V.; Rocha Junior, J.E.; Medeiros Neto, G.

    1987-01-01

    Serum triiodotironine (T3), thyroxine (T4), thyrotropin (TSH), free thyroxine (FT4) and reverse triiodothyronine (rT3) concentrations were determined by radioimmunoassay in 21 uremic patients on regular hemodialysis therapy (sera were collected immediately before dialysis) and 11 normal controls. In advanced chronic renal failure serum T3 and T4 were frequently decreased (86% and 57%, respectively). and serum rT3 was normal (81%) or subnormal (14%). The serum TSH and FT4 values were normal in all cases even when serum T3 and T4 concentrations were decreased below the normal range. The findings suggest that the measurement of serum TSH probably represents the most reliable differentiation between this disease with low T4 levels and primary hypothyroidism. (author)

  10. Total Thyroidectomy for Thyroid Cancer Followed by Thyroid Storm due to Thyrotropin Receptor Antibody Stimulation of Metastatic Thyroid Tissue

    DEFF Research Database (Denmark)

    Folkestad, Lars; Brandt, Frans; Brix, Thomas

    2017-01-01

    BACKGROUND: Graves disease (GD) is an autoimmune condition characterized by the presence of antibodies against the thyrotropin receptor (TRAB), which stimulate the thyroid gland to produce excess thyroid hormone. Theoretically, TRAB could stimulate highly differentiated thyroid cancer tissue and....../or metastases to produce thyroid hormone. CASE: A 68-year-old male, with weight loss and palpitations, was diagnosed with thyrotoxicosis. A later MRI, due to persistent shoulder pain, revealed multiple bone metastases. A biopsy was diagnostic for follicular variant of papillary thyroid carcinoma, and total...... treatment continued until after the fourth RAI dose. Hypothyroidism did not occur until following the fifth RAI treatment. SUMMARY AND CONCLUSIONS: We present a patient initially diagnosed with thyrotoxicosis and subsequently with metastatic follicular variant of papillary thyroid cancer. It is suggested...

  11. G.A.M.E.: GPU-accelerated mixture elucidator.

    Science.gov (United States)

    Schurz, Alioune; Su, Bo-Han; Tu, Yi-Shu; Lu, Tony Tsung-Yu; Lin, Olivia A; Tseng, Yufeng J

    2017-09-15

    GPU acceleration is useful in solving complex chemical information problems. Identifying unknown structures from the mass spectra of natural product mixtures has been a desirable yet unresolved issue in metabolomics. However, this elucidation process has been hampered by complex experimental data and the inability of instruments to completely separate different compounds. Fortunately, with current high-resolution mass spectrometry, one feasible strategy is to define this problem as extending a scaffold database with sidechains of different probabilities to match the high-resolution mass obtained from a high-resolution mass spectrum. By introducing a dynamic programming (DP) algorithm, it is possible to solve this NP-complete problem in pseudo-polynomial time. However, the running time of the DP algorithm grows by orders of magnitude as the number of mass decimal digits increases, thus limiting the boost in structural prediction capabilities. By harnessing the heavily parallel architecture of modern GPUs, we designed a "compute unified device architecture" (CUDA)-based GPU-accelerated mixture elucidator (G.A.M.E.) that considerably improves the performance of the DP, allowing up to five decimal digits for input mass data. As exemplified by four testing datasets with verified constitutions from natural products, G.A.M.E. allows for efficient and automatic structural elucidation of unknown mixtures for practical procedures. Graphical abstract .

  12. Metabolomic elucidation of pork from different crossbreds

    DEFF Research Database (Denmark)

    Bertram, Hanne Christine S.; Straadt, Ida Krestine; Clausen, Morten Rahr

    , and correlations between individual metabolites and sensory attributes were elucidated. A high content of carnosine in the meat was associated with a low value of many sensory attributes related to meat flavor/taste. Surprsingly, IMP and inosine were in general not correlated with sensory attributes related...... to meat flavor/taste. Water-holding capacity and oxygen radical absorbance capacity (ORAC) of the meat were determined to elucidate the correlations between individual metabolites and these two parameters that are of importance for the technological meat quality. In conclusion, the present study reveals...

  13. Protein alterations induced by long-term agonist treatment of HEK293 cells expressing thyrotropin-releasing hormone receptor and G11alpha protein

    Czech Academy of Sciences Publication Activity Database

    Drastichová, Z.; Bouřová, Lenka; Hejnová, L.; Jedelský, P.; Svoboda, Petr; Novotný, J.

    2010-01-01

    Roč. 109, č. 1 (2010), s. 255-264 ISSN 0730-2312 R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA309/06/0121; GA ČR(CZ) GD305/08/H037 Institutional research plan: CEZ:AV0Z50110509 Keywords : Thyrotropin-releasing hormone * Gq/11 protein * proteomics Subject RIV: ED - Physiology Impact factor: 3.122, year: 2010

  14. Structural elucidation of transmembrane domain zero (TMD0) of EcdL: A multidrug resistance-associated protein (MRP) family of ATP-binding cassette transporter protein revealed by atomistic simulation.

    Science.gov (United States)

    Bera, Krishnendu; Rani, Priyanka; Kishor, Gaurav; Agarwal, Shikha; Kumar, Antresh; Singh, Durg Vijay

    2017-09-20

    ATP-Binding cassette (ABC) transporters play an extensive role in the translocation of diverse sets of biologically important molecules across membrane. EchnocandinB (antifungal) and EcdL protein of Aspergillus rugulosus are encoded by the same cluster of genes. Co-expression of EcdL and echinocandinB reflects tightly linked biological functions. EcdL belongs to Multidrug Resistance associated Protein (MRP) subfamily of ABC transporters with an extra transmembrane domain zero (TMD0). Complete structure of MRP subfamily comprising of TMD0 domain, at atomic resolution is not known. We hypothesized that the transportation of echonocandinB is mediated via EcdL protein. Henceforth, it is pertinent to know the topological arrangement of TMD0, with other domains of protein and its possible role in transportation of echinocandinB. Absence of effective template for TMD0 domain lead us to model by I-TASSER, further structure has been refined by multiple template modelling using homologous templates of remaining domains (TMD1, NBD1, TMD2, NBD2). The modelled structure has been validated for packing, folding and stereochemical properties. MD simulation for 0.1 μs has been carried out in the biphasic environment for refinement of modelled protein. Non-redundant structures have been excavated by clustering of MD trajectory. The structural alignment of modelled structure has shown Z-score -37.9; 31.6, 31.5 with RMSD; 2.4, 4.2, 4.8 with ABC transporters; PDB ID 4F4C, 4M1 M, 4M2T, respectively, reflecting the correctness of structure. EchinocandinB has been docked to the modelled as well as to the clustered structures, which reveals interaction of echinocandinB with TMD0 and other TM helices in the translocation path build of TMDs.

  15. Isolation and structural elucidation of secondary metabolites from plants of the family Flacourtiaceae and Asclepiadaceae, and evaluation of biological activity of the sesquiterpene lactones and the diterpenes of Casearia sp

    International Nuclear Information System (INIS)

    Binns Quiros, Franklin

    2012-01-01

    A phytochemical study was realized of the plants Casearia aculeata, Casearia nitida and Asclepias verticillata, using experiments of nuclear magnetic resonance (NMR) of one and two dimensions. Ten secondary metabolites are isolated from C. aculeata and C. nitida. Three of the secondary metabolites have presented a structure known: a diterpene type kaurane: ent-kaurenic acid, a diterpene type pimarane: oxide of 3β-hydroximanoil and a steroid: 4-stigmastene-3-ona. Seven remaining compounds have corresponded to diterpene type clerodane of novel structure. Eight glycosides of poly oxidized pregnanes of novel structure are isolated from A. verticillata. In vitro tests of cytotoxicity and induction of caspase-3 are performed on leukemia cells type Jurkat T. These tests were performed at fifteen sesquiterpene lactones and at four diterpenes. The tests developed have had the purpose to describe structure-activity relationships that can be linked with the capacity to inhibit the factor NF-κB (sesquiterpene lactones) described in the literature and with the known mechanism of action induction of apoptosis in diterpenes type clerodane. A clear relationship between the capacity (high, intermediate or low) to inhibit the factor NF-κB and the capacity to induce to the caspase-3 has remained without observation in the sesquiterpene lactones. Some structural comparisons related with the cytotoxic capacity and the induction of the caspase-3 have been described for the series of LSs with carbon structure of pseudoguianolides. Diterpenes with carbon structure of diterpenes type clerodane have had greater cytotoxic activity with respect to without carbon structure. Diterpenes type clerodane isolated from the family Flacourtiaceae have been cytotoxics, their capacity to induce to the caspase-3 has remained without be nearby to induction realized by the actinomycin D (pure inducer of the caspase-3). (author) [es

  16. High prevalence of subclinical thyroid dysfunction and the relationship between thyrotropin levels and cardiovascular risk factors in residents of the coastal area of China.

    Science.gov (United States)

    Wang, Jinqian; Ma, Xiuyun; Qu, Shuying; Li, Yingzheng; Han, Lihui; Sun, Xun; Li, Peimei; Liu, Xue; Xu, Jinhua

    2013-01-01

    To investigate the prevalence of subclinical thyroid dysfunction and the relationship between thyrotropin levels and cardiovascular risk factors in residents of the coastal area of China. Atotalof4256individuals(mean[±SD]age50.51±14.24years; 2079 males, 2177 females,) were enrolled in the present study. Sex, blood pressure, body mass index, waist-to-hip ratio, serum levels of fasting glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, uric acid and smoking status were measured. The relationship between thyrotropin levels and cardiovascular risk factors was analyzed. The overall prevalence of thyroid dysfunction was 11.07%. The prevalence of subclinical hypothyroidism (6.32%) was higher than that of hyperthyroidism (1.53%). The prevalence of thyroid dysfunction among female subjects was higher than that among male subjects (16.54% versus 5.34%, respectively; Pcoastal area. Significant differences were detected with regard to body mass index, waist-to-hip ratio, fasting glucose levels, total cholesterol levels, triglyceride levels and smoking status according to different thyrotropin levels.

  17. Synthesis and NMR Elucidation of Novel Pentacycloundecane ...

    African Journals Online (AJOL)

    Herein we report the synthesis and NMR elucidation of five novel pentacycloundecane (PCU)-derived short peptides as potential HIV protease inhibitors. 1H and 13C spectral analysis show major overlapping of methine resonance of the PCU 'cage' thereby making it extremely difficult to assign the NMR signals. Attachment ...

  18. Elucidating the role of interfacial materials properties in microfluidic packages.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Thayne L.

    2013-01-01

    The purpose of this work was to discover a method to investigate the properties of interfaces as described by a numerical physical model. The model used was adopted from literature and applied to a commercially available multiphysics software package. By doing this the internal properties of simple structures could be elucidated and then readily applied to more complex structures such as valves and pumps in laminate microfluidic structures. A numerical finite element multi-scale model of a cohesive interface comprised of heterogeneous material properties was used to elucidate irreversible damage from applied strain energy. An unknown internal state variable was applied to characterize the damage process. Using a constrained blister test, this unknown internal state variable could be determined for an adherend/adhesive/adherend body. This is particularly interesting for laminate systems with microfluidic and microstructures contained within the body. A laminate structure was designed and fabricated that could accommodate a variety of binary systems joined using nearly any technique such as adhesive, welding (solvent, laser, ultrasonic, RF, etc.), or thermal. The adhesive method was the most successful and easy to implement but also one of the more difficult to understand, especially over long periods of time. Welding methods are meant to achieve a bond that is similar to bulk properties and so are easier to predict. However, methods of welding often produce defects in the bonds.. Examples of the test structures used to elucidate the internal properties of the model were shown and demonstrated. The real life examples used this research to improve upon current designs and aided in creating complex structures for sensor and other applications.

  19. Elucidating Functional Aspects of P-type ATPases

    DEFF Research Database (Denmark)

    Autzen, Henriette Elisabeth

    2015-01-01

    (endo)plasmic reticulum Ca2+-ATPase from fast-twitch skeletal muscle (SERCA1a) is associated with skin and muscle diseases, while mutations of the Cu+-ATPase (CopA) give rise to Cu+ deficiency or excess as seen in the devastating Menkes and Wilson’s diseases. Furthermore, the essential role that these proteins have...... similar to that of the wild type (WT) protein. The discrepancy between the newly determined crystal structure of LpCopA and the functional manifestations of the missense mutation in human CopA, could indicate that LpCopA is insufficient in structurally elucidating the effect of disease-causing mutations...

  20. Elucidation of the electrochromic mechanism of nanostructured iron oxides films

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Lobato, M.A.; Martinez, Arturo I.; Castro-Roman, M. [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav Campus Saltillo, Carr. Saltillo-Monterrey Km. 13, Ramos Arizpe, Coah. 25900 (Mexico); Perry, Dale L. [Mail Stop 70A1150, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Zarate, R.A. [Departamento de Fisica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Escobar-Alarcon, L. (Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico)

    2011-02-15

    Nanostructured hematite thin films were electrochemically cycled in an aqueous solution of LiOH. Through optical, structural, morphological, and magnetic measurements, the coloration mechanism of electrochromic iron oxide thin films was elucidated. The conditions for double or single electrochromic behavior are given in this work. During the electrochemical cycling, it was found that topotactic transformations of hexagonal crystal structures are favored; i.e. {alpha}-Fe{sub 2}O{sub 3} to Fe(OH){sub 2} and subsequently to {delta}-FeOOH. These topotactic redox reactions are responsible for color changes of iron oxide films. (author)

  1. Recombinant human thyrotropin stimulation prior to131I therapy in toxic multinodular goitre with low radioactive iodine uptake.

    Science.gov (United States)

    Azorín Belda, M J; Martínez Caballero, A; Figueroa Ardila, G C; Martínez Ramírez, M; Gómez Jaramillo, C A; Dolado Ardit, J I; Verdú Rico, J

    Stimulation with recombinant human thyrotropin (rhTSH) increases thyroid radioiodine uptake, and is an aid to 131 I therapy in non-toxic multinodular goitre (MNG). However, there are not many studies using rhTSH prior to 131 I in toxic multinodular goitre to improve hyperthyroidism and compressive symptoms. A prospective study was conducted on patients with MNG and hyperthyroidism. Patients were recruited consecutively and divided into group I, stimulated with 0.3mg of rhTSH before radioiodine therapy, and a control group or group II, without stimulation. Thyroid function, radioiodine thyroid uptake, thyroid weight, and compressive symptoms were measured, and patients were followed-up for 9 months. Group I consisted of 16 patients (14 women), with a mean age 69.7 years, and group II with 16 patients (12 women), with a mean age 70.7 years. After stimulation with 0.3mg rhTSH in group I, 131 I uptake (RAIU) at 24h increased by 78.4%, and the estimated absorbed dose by 89.3%. In group II, the estimated absorbed dose was lower than group I after stimulation with rhTSH (29.8Gy vs. 56.4Gy; P=0.001). At 9 months of follow-up, hyperthyroidism was controlled in 87.5% of patients in group I, and 56.2% in group II (P=0.049). The mean reduction in thyroid weight was higher in group I than in group II (39.3% vs. 26.9%; P=0.017), with a tendency towards subjective improvement of compressive symptoms in group I, although non-significant. Only 2 patients described tachycardias after rhTSH administration, which were resolved with beta-blockers. Stimulation with 0.3mg of recombinant human thyrotropin prior to radioiodine therapy achieves a reduction in thyroid weight and functional improvement in patients with hyperthyroidism and multinodular goitre with low uptake, and with no need for hospital admission. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  2. Dose-dependent effects of 17-ß-estradiol on pituitary thyrotropin content and secretion in vitro

    Directory of Open Access Journals (Sweden)

    Moreira R.M.

    1997-01-01

    Full Text Available We studied the basal and thyrotropin-releasing hormone (TRH (50 nM induced thyrotropin (TSH release in isolated hemipituitaries of ovariectomized rats treated with near-physiological or high doses of 17-ß-estradiol benzoate (EB; sc, daily for 10 days or with vehicle (untreated control rats, OVX. One group was sham-operated (normal control. The anterior pituitary glands were incubated in Krebs-Ringer bicarbonate medium, pH 7.4, at 37oC in an atmosphere of 95% O2/5% CO2. Medium and pituitary TSH was measured by specific RIA (NIDDK-RP-3. Ovariectomy induced a decrease (P<0.05 in basal TSH release (normal control = 44.1 ± 7.2; OVX = 14.7 ± 3.0 ng/ml and tended to reduce TRH-stimulated TSH release (normal control = 33.0 ± 8.1; OVX = 16.6 ± 2.4 ng/ml. The lowest dose of EB (0.7 µg/100 g body weight did not reverse this alteration, but markedly increased the pituitary TSH content (0.6 ± 0.06 µg/hemipituitary; P<0.05 above that of OVX (0.4 ± 0.03 µg/hemipituitary and normal rats (0.46 ± 0.03 µg/hemipituitary. The intermediate EB dose (1.4 µg/100 g body weight induced a nonsignificant tendency to a higher TSH response to TRH compared to OVX and a lower response compared to normal rats. Conversely, in the rats treated with the highest dose (14 µg/100 g body weight, serum 17-ß-estradiol was 17 times higher than normal, and the basal and TRH-stimulated TSH release, as well as the pituitary TSH content, was significantly (P<0.05 reduced compared to normal rats and tended to be even lower than the values observed for the vehicle-treated OVX group, suggesting an inhibitory effect of hyperestrogenism. In conclusion, while reinforcing the concept of a positive physiological regulatory role of estradiol on the TSH response to TRH and on the pituitary stores of the hormone, the present results suggest an inhibitory effect of high levels of estrogen on these responses

  3. Electronic structure of ThRu2Si2 studied by angle-resolved photoelectron spectroscopy: Elucidating the contribution of U 5 f states in URu2Si2

    Science.gov (United States)

    Fujimori, Shin-ichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saitoh, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Matsumoto, Yuji; Yamamoto, Etsuji; Tateiwa, Naoyuki; Haga, Yoshinori

    2017-09-01

    The electronic structure of ThRu2Si2 was studied using angle-resolved photoelectron spectroscopy (ARPES) with incident photon energies of h ν =655 -745 eV. Detailed band structure and the three-dimensional shapes of Fermi surfaces were derived experimentally, and their characteristic features were mostly explained by means of band-structure calculations based on density-functional theory. Comparison of the experimental ARPES spectra of ThRu2Si2 with those of URu2Si2 shows that they have considerably different spectral profiles, particularly in the energy range of 1 eV from the Fermi level, suggesting that U 5 f states are substantially hybridized in these bands. The relationship between the ARPES spectra of URu2Si2 and ThRu2Si2 is very different from the one between the ARPES spectra of CeRu2Si2 and LaRu2Si2 , where the intrinsic difference in their spectra is limited only in the very vicinity of the Fermi energy. The present result suggests that the U 5 f electrons in URu2Si2 have strong hybridization with ligand states and have an essentially itinerant character.

  4. Elucidation of the molecular structure of hydrated vanadium oxide species by X-ray absorption spectroscopy: correlation between the V...V coordination number and distance and the point of zero charge of the support oxide.

    Science.gov (United States)

    Keller, Daphne E; Koningsberger, Diek C; Weckhuysen, Bert M

    2006-11-07

    The effect of the point of zero charge (PZC) of the support oxide (Al(2)O(3), Nb(2)O(5), SiO(2) and ZrO(2)) on the molecular structure of hydrated vanadium oxide species has been investigated with EXAFS spectroscopy for low-loaded vanadium oxide catalysts. It was found that the degree of clustering (i.e., the V[dot dot dot]V coordination number) and the V...V distance increase with decreasing PZC of the support oxide; i.e., Al(2)O(3) (8.7) vanadium oxide exhibited a clear alteration in the position of the oxygen atoms surrounding the central vanadium atom and the number of oxygen atoms around vanadium increased to five. In contrast, only minor changes in the molecular structure were detected for the alumina-, niobia- and zirconia-supported vanadium oxide catalysts. Based on a detailed analysis of the EXAFS data a semi-quantitative distribution of vanadium oxide species present on the surface of the different support oxides can be obtained, which is in good agreement with earlier characterization studies primarily making use of Raman spectroscopy.

  5. One Step Toward a New Generation of C-MOS Compatible Oxide P-N Junctions: Structure of the LSMO/ZnO Interface Elucidated by an Experimental and Theoretical Synergic Work.

    Science.gov (United States)

    Pullini, Daniele; Sgroi, Mauro Francesco; Mahmoud, Agnes; Gauquelin, Nicolas; Maschio, Lorenzo; Ferrari, Anna Maria; Groenen, Rik; Damen, Cas; Rijnders, Guus; van den Bos, Karel Hendrik Wouter; Van Aert, Sandra; Verbeeck, Johan

    2017-06-21

    Heterostructures formed by La 0.7 Sr 0.3 MnO 3 /ZnO (LSMO/ZnO) interfaces exhibit extremely interesting electronic properties making them promising candidates for novel oxide p-n junctions, with multifunctional features. In this work, the structure of the interface is studied through a combined experimental/theoretical approach. Heterostructures were grown epitaxially and homogeneously on 4″ silicon wafers, characterized by advanced electron microscopy imaging and spectroscopy and simulated by ab initio density functional theory calculations. The simulation results suggest that the most stable interface configuration is composed of the (001) face of LSMO, with the LaO planes exposed, in contact with the (112̅0) face of ZnO. The ab initio predictions agree well with experimental high-angle annular dark field scanning transmission electron microscopy images and confirm the validity of the suggested structural model. Electron energy loss spectroscopy confirms the atomic sharpness of the interface. From statistical parameter estimation theory, it has been found that the distances between the interfacial planes are displaced from the respective ones of the bulk material. This can be ascribed to the strain induced by the mismatch between the lattices of the two materials employed.

  6. The study on mutations of the gene of extracellular domain of human thyrotropin receptor in the patients with thyroid diseases

    International Nuclear Information System (INIS)

    Zhang Zuncheng; Fang Peihua; Tan Jian; Lu Mei

    2002-01-01

    Objective: To define the sequence of the gene of extracellular domain of normal human thyrotropin receptor (hTSHR) and to investigate the mutations of the gene in the patients with thyroid diseases. Methods: Total RNAs were extracted from the thyroid tissue of four normal controls, twelve Graves' disease, four Hashimoto's thyroiditis and eleven nodular goiter patients. The extracellular domain of hTSHR genes were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and sequenced with CEQ 2000 Genetic Analyzer. Results: The normal controls and the patients with thyroid disease had the same gene sequences of the extracellular domain of hTSHR. No mutation was found, except a silent base exchange in exon 7 (Asn187) at 661 base, in which 20 samples were 'T', 11 samples were 'C', without changes of amino acid of the TSHR. Conclusions: This study has not revealed mutations in the gene of extracellular domain of hTSHR. Other molecular pathogenetic mechanisms may be involved and more research is demanded

  7. Human corticotropin-releasing hormone and thyrotropin-releasing hormone modulate the hypercapnic ventilatory response in humans.

    Science.gov (United States)

    Schulz, R; Nink, M; Werner, G S; Andreas, S; Kreuzer, H; Beyer, J; Lehnert, H

    1996-11-01

    Human corticotropin-releasing hormone (hCRH) and thyrotropin-releasing hormone (TRH) are known to stimulate ventilation after i.v. administration in humans. In a placebo-controlled, single-blind study we aimed to clarify if both peptides act by altering central chemosensitivity. Two subsequent CO2-rebreathing tests were performed in healthy young volunteers. During the first test 0.9% NaCl was given i.v.; during the second test 200 micrograms of hCRH (n = 12) or 400 micrograms of TRH (n = 6) was administered i.v. Nine subjects received 0.9% NaCl i.v. during both rebreathing manoeuvres. The CO2-response curves for the two tests were compared within the same subject. In the hCRH group a marked parallel shift of the CO2-response curve to the left was observed after hCRH (P < 0.01). The same effect occurred following TRH but was less striking (P = 0.05). hCRH and TRH caused a reduction in the CO2 threshold. The CO2-response curves in the control group were nearly identical. The results indicate an additive effect of both releasing hormones on the hypercapnic ventilatory response in humans, presumably independent of central chemosensitivity.

  8. PET Study in a Patient with Spinocerebellar Degeneration before and after Long-Term Administration of Thyrotropin Releasing Hormone

    Directory of Open Access Journals (Sweden)

    H. Tanji

    1996-01-01

    Full Text Available We studied the chronic effect of thyrotropin releasing hormone (TRH in a patient with spinocerebellar degeneration by measuring cerebral metabolic rate for glucose (CMRG1c using 2-[18F]fluoro-2-deoxy-D-glucose (18FDG and positron emission tomography (PET. A 56-year-old female, who had suffered from progressive ataxia for 2 years, was treated by intravenous administration of 2 mg TRH for 3 weeks, and CMRG1c of the brain was measured before and after treatment. CMRG1c was markedly decreased in the cerebellum and there was no significant difference before and after the treatment, i.e. mean CMRG1c values were 4.92 and 4.90 mg/100 g/min, and the ratios of the cerebellum versus the frontal cortex were 0.50 and 0.51, respectively. The degree of disequilibrium of her body examined with stabilography became better by the 19th day and further improved by the 26th day after the start of TRH treatment. Based on the present study we conclude that long-term administration of TRH did not improve CMRG1c in the cerebellum, but evidently improved the sway of gravity center by stabilography. We speculate that the chronic effect of TRH was not necessarily due to an improvement of cerebellar function, because TRH receptors are widely distributed throughout the central nervous system.

  9. Development of an efficient E. coli expression and purification system for a catalytically active, human Cullin3-RINGBox1 protein complex and elucidation of its quaternary structure with Keap1

    International Nuclear Information System (INIS)

    Small, Evan; Eggler, Aimee; Mesecar, Andrew D.

    2010-01-01

    Research highlights: → A novel expression strategy was used to purify Cul3-Rbx1 from E. coli. → The Cul3-Rbx1 complex is fully active and catalyzes ubiquitination of Nrf2 in vitro. → Cul3, Rbx1, and Keap1 form a complex with unique stoichiometry of 1:1:2. -- Abstract: The Cullin3-based E3 ubiquitin ligase complex is thought to play an important role in the cellular response to oxidative stress and xenobiotic assault. While limited biochemical studies of the ligase's role in these complex signaling pathways are beginning to emerge, structural studies are lagging far behind due to the inability to acquire sufficient quantities of full-length, highly pure and active Cullin3. Here we describe the design and construction of an optimized expression and purification system for the full-length, human Cullin3-RINGBox 1 (Rbx1) protein complex from Escherichia coli. The dual-expression system is comprised of codon-optimized Cullin3 and Rbx1 genes co-expressed from a single pET-Duet-1 plasmid. Rapid purification of the Cullin3-Rbx1 complex is achieved in two steps via an affinity column followed by size-exclusion chromatography. Approximately 15 mg of highly pure and active Cullin3-Rbx1 protein from 1 L of E. coli culture can be achieved. Analysis of the quaternary structure of the Cullin3-Rbx1 and Cullin3-Rbx1-Keap1 complexes by size-exclusion chromatography and analytical ultracentrifugation indicates a 1:1 stoichiometry for the Cullin3-Rbx1 complex (MW = 111 kDa), and a 1:1:2 stoichiometry for the Cullin3-Rbx1-Keap1 complex (MW = 280 kDa). This latter complex has a novel quaternary structural organization for cullin E3 ligases, and it is fully active based on an in vitro Cullin3-Rbx1-Keap1-Nrf2 ubiquitination activity assay that was developed and optimized in this study.

  10. Fast and Accurate Identification of Cross-Linked Peptides for the Structural Analysis of Large Protein Complexes and Elucidation of Interaction Networks. / Tahir, Salman; Bukowski-Wills, Jimi-Carlo; Rasmussen, Morten; Rappsilber, Juri

    DEFF Research Database (Denmark)

    Rasmussen, Morten

    Aspect: Our software efficiently and correctly identifies cross-links within large protein complexes, facilitating the construction of low-resolution 3D-models and interaction networks   .Introduction Chemical cross-linking of peptides coupled with mass spectrometry emerges as a powerful method...... accuracy library of over 1000 synthetic peptides to understand the fragmentation behaviour of cross-linked peptides. This allows us to pre-process spectra through de-isotoping, charge reduction and the removal of loss-of-water/ammonia peaks. Furthermore, using this information we are able to reduce...... the complexity of searching to essentially two successive searches of linear peptides as opposed to analyzing every possible combination of peptides that could potentially cross-link. We achieve further speedup using parallelization and data-structures that complement the nature of the data we search...

  11. Hydrothermal synthesis, structural elucidation, spectroscopic studies, thermal behavior and luminescence properties of a new 3-d compound: FeAlF2(C10H8N2)(HPO4)2(H2O)

    Science.gov (United States)

    Bouzidia, Nabaa; Salah, Najet; Hamdi, Besma; Ben Salah, Abdelhamid

    2017-04-01

    The study of metal phosphate has been a proactive field of research thanks to its applied and scientific importance, especially in terms of the development of optical devices such as solid state lasers as well as optical fibers. The present paper seeks to investigate the synthesis, crystal structure, elemental analysis and properties of FeAlF2(C10H8N2)(HPO4)2(H2O) compound investigated by spectroscopic studies (FT-IR and FT-Raman), thermal behavior and luminescence. The Hirshfeld surface analysis and 2-D fingerprint plot have been performed to explore the behavior of these weak interactions and crystal cohesion. This investigation shows that the molecules are connected by hydrogen bonds of the type Osbnd H⋯O and Osbnd H⋯F. In addition, the 2,2'‒bipyridine ligand plays a significant role in the construction of 3-D supramolecular framework via π‒π stacking. FT‒IR and FT‒Raman spectra were used so as to ease the responsibilities of the vibration modes of the title compound. The thermal analysis (TGA) study shows a mass loss evolution as a temperature function. Finally, the optical properties were evaluated by photoluminescence spectroscopy.

  12. Tetradentate-arm Schiff base derived from the condensation reaction of 3,3′-dihydroxybenzidine, glyoxal/diacetyl and 2-aminophenol: Designing, structural elucidation and properties of their binuclear metal(II complexes

    Directory of Open Access Journals (Sweden)

    E. Akila

    2017-05-01

    Full Text Available The novel binuclear Schiff base complexes were prepared by the reaction of 3,3′-dihydroxybenzidine, glyoxal/diacetyl and 2-aminophenol in 1:2:2 M ratio. The binucleating Schiff base ligand and its complexes of Cu(II, Ni(II and VO(II ions were characterized by elemental analysis, molar conductance, 1H NMR, infrared, electronic spectra, cyclic voltammetry, thermal, magnetic and EPR studies. The low molar conductance values of the complexes support the non-electrolytic in nature. In IR spectra, the comparison of shift in frequency of the complexes with the ligand reveals the coordination of donor atom to the metal atom. The binuclear nature of the complexes is assessed from their magnetic susceptibility values. The electronic and EPR spectra of the metal complexes provide information about the geometry of the complexes and are in good agreement with the proposed square planar geometry for Cu(II, Ni(II and square pyramidal for VO(II complexes. Molecular modeling has been used to suggest the structure of the complexes. The DNA cleavage ability of the complexes was monitored by gel electrophoresis using supercoiled pUC18 DNA. The metal complexes were screened for their antibacterial activities against pathogenic bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Bacillus subtilis. The activity data show that the metal complexes are more potent activity than the parent Schiff base ligand against microorganisms.

  13. Spectral analysis, structural elucidation, and evaluation of both nonlinear optical properties and chemical reactivity of a newly synthesized ethyl-3,5-dimethyl-4-[(toluenesulfonyl)-hydrazonomethyl]-1H-pyrrole-2-carboxylate through experimental studies and quantum chemical calculations

    Science.gov (United States)

    Singh, R. N.; Rawat, Poonam

    2013-12-01

    As part of study of hydrazide-hydrazones, we have synthesized ethyl-3,5-dimethyl-4-[(toluenesulfonyl)-hydrazonomethyl]-1H-pyrrole-2-carboxylate (EDTHMPC) and characterized by elemental analysis, FT-IR, UV-Vis, 1H, 13C NMR and Mass spectroscopy. The structure, spectral and thermodynamic parameters of EDTHMPC were quantum chemically calculated performing density functional level theory (DFT) with B3LYP functional and 6-31G (d,p) basis set. Electrophilic charge transfer (ECT) values of interacting molecules indicate that charge flows from p-toluene sulphonyl-hydrazide to ethyl-3,5-dimethyl-4-formyl-1H-pyrrole-2-carboxylate confirming the formation of product by nucleophilic attack. The calculated and experimental wavenumbers analysis confirms the formation of dimer. The calculated changes in thermodynamic quantities during dimer formation in gaseous phase have the negative values for ΔH, ΔG (kcal/mol) and ΔS (cal/mol-K) indicating that the dimer formation is exothermic and will proceed only at low temperature. The strength and nature of hydrogen bonding and weak interactions in dimer have been analyzed by 'Quantum theory of atoms in molecules' (QTAIM) and found to be five types of interactions in which three types are (C⋯N, CH⋯O and CH⋯HC) intramolecular and two types are (CO⋯HN and CH⋯OC) intermolecular. The calculated binding energy of dimer using DFT and QTAIM theory are 14.32 and 15.41 kcal/mol, respectively. The β0 value for monomer is calculated as 11.54 x 10-30 esu indicating microscopic nonlinear optical (NLO) behavior with non-zero values.

  14. The structural analysis of the pro-oxidant copper-binding site of denatured apo-H43R SOD1 and the elucidation of the origin of the acquisition of the pro-oxidant activity.

    Science.gov (United States)

    Fujimaki, Nobuhiro; Miura, Takashi; Nakabayashi, Takakazu

    2016-02-14

    The pathogenesis of amyotrophic lateral sclerosis (ALS) is associated with mutations of Cu,Zn-superoxide dismutase (SOD1), which is a representative antioxidant enzyme. A previous study showed that the denatured apo-form of an ALS-linked mutant of human SOD1, His43 → Arg (H43R), obtains pro-oxidant activity as the reverse behavior of the native antioxidant activity by rebinding Cu(2+), which is considered to be closely related to the development of ALS. The Cu(2+)-binding site in denatured apo-H43R can be regarded as the center of the pro-oxidant activity, causing cellular oxidative stress. In the present study, the structure of the Cu(2+)-binding site of denatured apo-H43R was investigated to clarify the mechanism of the acquisition of the pro-oxidant activity. His residues constructing the Cu(2+)-binding site in denatured apo-H43R were experimentally assigned by absorption and fluorescence-based assays of SOD1 mutants, in which each of the seven His residues in H43R SOD1 is replaced with Ala. It was found that His120 is not involved with the Cu(2+)-binding site after denaturation, although the other His residues constructing the metal-binding site remain constant after denaturation. The disappearance of His120 from the Cu(2+)-binding site is therefore considered to be one of the important factors in obtaining the pro-oxidant activity. The mechanism of the acquisition of the pro-oxidant activity is discussed based on the results obtained.

  15. Thermally induced solid-state transformation of cimetidine. A multi-spectroscopic/chemometrics determination of the kinetics of the process and structural elucidation of one of the products as a stable N{sub 3}-enamino tautomer

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Natalia L.; Simonetti, Sebastian O.; Maggio, Rubén M.; Kaufman, Teodoro S., E-mail: kaufman@iquir-conicet.gov.ar

    2015-05-22

    Highlights: • Thermally stressed cimetidine above its melting point affords a stable N{sub 3} tautomer. • Multi-spectroscopic/chemometric approach developed to monitor tautomerization. • First combined use of NMR, UV and IR spectroscopies with chemometrics. • Solid cimetidine suffers first order degradation upon submission to dry heat. • Theoretical chemistry analysis confirmed the relative stability of cimetidine tautomer. - Abstract: Exposure of cimetidine (CIM) to dry heat (160–180 °C) afforded, upon cooling, a glassy solid containing new and hitherto unknown products. The kinetics of this process was studied by a second order chemometrics-assisted multi-spectroscopic approach. Proton and carbon-13 nuclear magnetic resonance (NMR), as well as ultraviolet and infrared spectroscopic data were jointly used, whereas multivariate curve resolution with alternating least squares (MCR-ALS) was employed as the chemometrics method to extract process information. It was established that drug degradation follows a first order kinetics. One of the products was structurally characterized by mono- and bi-dimensional NMR experiments. It was found to be the N{sub 3}-enamino tautomer (TAU) of CIM, resulting from the thermal isomerization of the double bond of the cyanoguanidine moiety of the drug, from the imine form to its N{sub 3}-enamine state. The thus generated tautomer demonstrated to be stable for months in the glassy solid and in methanolic solutions. A theoretical study of CIM and TAU revealed that the latter is less stable; however, the energy barrier for tautomer interconversion is high enough, precluding the process to proceed rapidly at room temperature.

  16. Synthesis and structure elucidation of new μ-oxamido-bridged dicopper(II) complex with in vitro anticancer activity: A combined study from experiment verification and docking calculation on DNA/protein-binding property.

    Science.gov (United States)

    Zhu, Ling; Zheng, Kang; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2016-02-01

    A new oxamido-bridged dicopper(II) complex with formula of [Cu2(deap)(pic)2], where H2deap and pic represent N,N'-bis[3-(diethylamino)propyl]oxamide and picrate, respectively, was synthesized and characterized by elemental analyses, molar conductance measurements, IR and electronic spectral study, and single-crystal X-ray diffraction. The crystal structure analyses revealed that the two copper(II) atoms in the dicopper(II) complex are bridged by the trans-deap(2-) ligand with the distances of 5.2116(17)Å, and the coordination environment around the copper(II) atoms can be described as a square-planar geometry. Hydrogen bonding and π-π stacking interactions link the dicopper(II) complex into a three-dimensional infinite network. The DNA/protein-binding properties of the complex are investigated by molecular docking and experimental assays. The results indicate that the dicopper(II) complex can interact with HS-DNA in the mode of intercalation and effectively quench the intrinsic fluorescence of protein BSA by 1:1 binding with the most possible binding site in the proximity of Trp134. The in vitro anticancer activities suggest that the complex is active against the selected tumor cell lines, and IC50 values for SMMC-7721 and HepG2 are lower than cisplatin. The effects of the electron density distribution of the terminal ligand and the chelate ring arrangement around copper(II) ions bridged by symmetric N,N'-bis(substituted)oxamides on DNA/BSA-binding ability and in vitro anticancer activity are preliminarily discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Combined treatment of the highly differentiated cancer of thyroid gland: recombinant human thyrotropin-alpha is in the focus

    Directory of Open Access Journals (Sweden)

    Петро Петрович Зінич

    2016-03-01

    Full Text Available Aim. An assessment of the effectiveness of treatment and also the detection of advantages of prescription of the recombinant human thyrotropin-alpha (rhTTH in postoperative period in patients with the highly differentiated cancer of thyroid gland (HDCTG comparing with traditional method of preparation (cancellation of the thyroid hormones to the treatment using radioactive iodine.Methods. There was carried out an analysis of the treatment of 100 patients with HDCTG: the control group – 56 patients (standard tactics, the main group – 44 patients (the use of rhTTH. There was carried out the scanning of all the body in 48 hours after administration of 150 MBc 131I, was detected the concentration of thyroglobulin and antibodies to it, the level of thyrotropic hormone, was carried out the ultrasound of neck and also questioning about the life quality. Results. The comparative analysis of the data of studied groups demonstrated the reliably less number of isotope accumulation nidi in persons whose preparation was carried out with the help of rhTTH, that is the absence of visible catch in 25 % of cases in patients from the category of low risk (in 5,7 times higher than in analogous cohort of the control group– 4,4 % and in 7,1 % – in patients from the high risk group. The number of cases of the minimal visible catch <0,1 % in patients of the high risk category is reliably higher comparing with the control one (78,1 % and 56,1 % respectively, Р<0,01. The level of stimulated serum thyroglobulin >2,0 ng/ml was detected in 3,1 % of cases in the main group whereas in the control one – 13,1 %; within 1,0–2,0 ng/ml was detected reliably less often in the main group: 8,3 % in the low risk patients and 12,5 % – in the high risk ones comparing with the control group (28,6 % and 31,7 % respectively. The effective decrease of thyroglobulin level in 6–8 months after radioiodine therapy was detected in 22 (91,7 % patients of the main low risk group

  18. Mediator subunit MED1 is a T3-dependent and T3-independent coactivator on the thyrotropin β gene promoter

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Keiji; Oda, Kasumi; Mizuta, Shumpei; Ishino, Ruri; Urahama, Norinaga; Hasegawa, Natsumi [Laboratory of Hematology, Division of Medical Biophysics, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142 (Japan); Roeder, Robert G. [Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States); Ito, Mitsuhiro, E-mail: itomi@med.kobe-u.ac.jp [Laboratory of Hematology, Division of Medical Biophysics, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142 (Japan); Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States); Department of Family and Community Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 654-0142 (Japan); Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 159-8555 (Japan)

    2013-10-11

    Highlights: •MED1 is a bona fide T3-dependent coactivator on TSHB promoter. •Mice with LxxLL-mutant MED1 have attenuated TSHβ mRNA and thyroid hormone levels. •MED1 activates TSHB promoter T3-dependently in cultured cells. •T3-dependent MED1 action is enhanced when SRC1/SRC2 or HDAC2 is downregulated. •MED1 is also a T3-independent GATA2/Pit1 coactivator on TSHB promoter. -- Abstract: The MED1 subunit of the Mediator transcriptional coregulator complex is a nuclear receptor-specific coactivator. A negative feedback mechanism of thyroid-stimulating hormone (TSH, or thyrotropin) expression in the thyrotroph in the presence of triiodothyronine (T3) is employed by liganded thyroid hormone receptor β (TRβ) on the TSHβ gene promoter, where conventional histone-modifying coactivators act as corepressors. We now provide evidence that MED1 is a ligand-dependent positive cofactor on this promoter. TSHβ gene transcription was attenuated in MED1 mutant mice in which the nuclear receptor-binding ability of MED1 was specifically disrupted. MED1 stimulated GATA2- and Pit1-mediated TSHβ gene promoter activity in a ligand-independent manner in cultured cells. MED1 also stimulated transcription from the TSHβ gene promoter in a T3-dependent manner. The transcription was further enhanced when the T3-dependent corepressors SRC1, SRC2, and HDAC2 were downregulated. Hence, MED1 is a T3-dependent and -independent coactivator on the TSHβ gene promoter.

  19. TRH [thyrotropin-releasing hormone] and BAY K 8644 synergistically stimulate prolactin release but not 45Ca2+ uptake

    International Nuclear Information System (INIS)

    Pachter, J.A.; Law, G.J.; Dannies, P.S.

    1988-01-01

    Thyrotropin-releasing hormone (TRH) and the Ca 2+ -channel agonist BAY K 8644 each induced transient increases in prolactin secretion from primary cultures of rat anterior pituitary cells in perfusion. When BAY K 8644 was added after a TRH-induced secretory peak, the additional effect of BAY K 8644 on prolactin release was approximately twofold greater over a 30-min period than the effect of BAY K 8644 on previously untreated cells. TRH and BAY K 8644 were also synergistic when added in the opposite order or simultaneously. Substitution of other agents for BAY K 8644 revealed that only high K + was at least additive with TRH in stimulating prolactin secretion; treatment with TRH inhibited, rather than facilitated, subsequent stimulation of prolactin secretion by angiotensin II or the ionophore A23187. The cooperative effect was not specific for TRH because BAY K 8644 also acted synergistically with angiotensin II or 40 mM K + . In GH 4 C 1 cells, in which TRH and BAY K 8644 were also synergistic in releasing prolactin, measurements with the fluorescent indicator indo-1 showed that TRH and BAY K 8644 could each elevate cytosolic Ca 2+ above the level stimulated by the other. Unexpectedly, TRH was found to inhibit BAY K 8644-stimulated 45 Ca 2+ uptake in both GH 4 C 1 and primary cultured cells. These results indicate that BAY K 8644 and TRH synergistically stimulate prolactin secretion by a mechanism other than a cooperative effect on the activity of dihydropyridine-sensitive Ca 2+ channels

  20. Leptin amplifies the action of thyrotropin-releasing hormone in the solitary nucleus: an in vitro calcium imaging study.

    Science.gov (United States)

    Rogers, Richard C; McDougal, David H; Hermann, Gerlinda E

    2011-04-18

    Leptin exerts a powerful permissive influence on neurogenic thermogenesis. During starvation and an absence of leptin, animals cannot produce thermogenic reactions to cold stress. However, thermogenesis is rescued by restoring leptin. We have previously observed a highly cooperative interaction between leptin and thyrotropin-releasing hormone [TRH] to activate hindbrain-generated thermogenic responses (Hermann et al., 2006). In vivo physiological studies (Rogers et al., 2009) suggested that the thermogenic impact of TRH in the hindbrain is amplified by the action of leptin through a leptin receptor-mediated production of phosphoinositol-trisphosphate [PIP3]. In turn, PIP3 can activate a tyrosine kinase whose target is the Src-SH2 regulatory site on the phospholipase C [PLC] complex. The TRH receptor signals through the PLC complex. Our immunohistochemical studies (Barnes et al., 2010) suggest that this transduction interaction between leptin and TRH occurs within neurons of the solitary nucleus [NST], though this interaction had not been verified. The present in vitro live cell calcium imaging study shows that while medial NST neurons are rarely activated by leptin alone, leptin pre-treatment significantly augments NST neurons' responsiveness to TRH. This leptin-mediated priming of NST neurons was uncoupled by pre-treatment with the phosphoinositide 3-kinase [PI3K] inhibitor [wortmannin], the phospholipase C inhibitor [U73122] and the Src-SH2 antagonist [PP2]. TTX did not eliminate the synergistic response of the agonists, thus the sensitization cannot be attributed to pre-synaptic mechanisms. It seems likely that NST neurons are involved in the leptin-mediated increase in BAT temperature by sensitizing the TRH-PLC-IP3-calcium release mechanism. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Lateral hypothalamic thyrotropin-releasing hormone neurons: distribution and relationship to histochemically defined cell populations in the rat.

    Science.gov (United States)

    Horjales-Araujo, E; Hellysaz, A; Broberger, C

    2014-09-26

    The lateral hypothalamic area (LHA) constitutes a large component of the hypothalamus, and has been implicated in several aspects of motivated behavior. The LHA is of particular relevance to behavioral state control and the maintenance of arousal. Due to the cellular heterogeneity of this region, however, only some subpopulations of LHA cells have been properly anatomically characterized. Here, we have focused on cells expressing thyrotropin-releasing hormone (TRH), a peptide found in the LHA that has been implicated as a promoter of arousal. Immunofluorescence and in situ hybridization were used to map the LHA TRH population in the rat, and cells were observed to form a large ventral cluster that extended throughout almost the entire rostro-caudal axis of the hypothalamus. Almost no examples of coexistence were seen when sections were double-stained for TRH and markers of other LHA populations, including the peptides hypocretin/orexin, melanin-concentrating hormone and neurotensin. In the juxtaparaventricular area, however, a discrete group of TRH-immunoreactive cells were also stained with antisera against enkephalin and urocortin 3. Innervation from the metabolically sensitive hypothalamic arcuate nucleus was investigated by double-staining for peptide markers of the two centrally projecting groups of arcuate neurons, agouti gene-related peptide and α-melanocyte-stimulating hormone, respectively; both populations of terminals were observed forming close appositions on TRH cells in the LHA. The present study indicates that TRH-expressing cells form a unique population in the LHA that may serve as a link between metabolic signals and the generation of arousal. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. Thyrotropin regulates IL-6 expression in CD34+ fibrocytes: clear delineation of its cAMP-independent actions.

    Directory of Open Access Journals (Sweden)

    Nupur Raychaudhuri

    Full Text Available IL-6 plays diverse roles in normal and disease-associated immunity such as that associated with Graves' disease (GD. In that syndrome, the orbit undergoes remodeling during a process known as thyroid-associated ophthalmopathy (TAO. Recently, CD34(+ fibrocytes were found to infiltrate the orbit in TAO where they transition into CD34(+ orbital fibroblasts. Surprisingly, fibrocytes display high levels of functional thyrotropin receptor (TSHR, the central antigen in GD. We report here that TSH and the pathogenic anti-TSHR antibodies that drive hyperthyroidism in GD induce IL-6 expression in fibrocytes and orbital fibroblasts. Unlike TSHR signaling in thyroid epithelium, that occurring in fibrocytes is completely independent of adenylate cyclase activation and cAMP generation. Instead TSH activates PDK1 and both AKT/PKB and PKC pathways. Expression and use of PKCβII switches to that of PKCµ as fibrocytes transition to TAO orbital fibroblasts. This shift is imposed by CD34(- orbital fibroblasts but reverts when CD34(+ fibroblasts are isolated. The up-regulation of IL-6 by TSH results from coordinately enhanced IL-6 gene promoter activity and increased IL-6 mRNA stability. TSH-dependent IL-6 expression requires activity at both CREB (-213 to -208 nt and NF-κB (-78 to -62 nt binding sites. These results provide novel insights into the molecular action of TSH and signaling downstream for TSHR in non-thyroid cells. Fibrocytes neither express adenylate cyclase nor generate cAMP and thus these findings are free from any influence of cAMP-related signaling. They identify potential therapeutic targets for TAO.

  3. Serum Thyrotropin Is Positively Correlated with the Metabolic Syndrome Components of Obesity and Dyslipidemia in Chinese Adolescents

    Directory of Open Access Journals (Sweden)

    Jingfan Zhang

    2014-01-01

    Full Text Available Metabolic syndrome is a medical disorder characterized by obesity, hyperglycemia, dyslipidemia, and hypertension. Thyroid hormone has been shown to affect many metabolic processes. This study was undertaken to explore the relationship between serum thyrotropin and components of metabolic syndrome in Chinese adolescents. Waist circumference (76.4 ± 10.7 versus 70.0 ± 10.6 cm, P = 0.006 and body mass index (23.90 ± 4.20 versus 21.51 ± 4.16 kg/m2, P = 0.011 were significantly greater among adolescents with subclinical hypothyroidism compared with euthyroid subjects. The risk of obesity in the subclinical hypothyroid group was 3.444 times that in the euthyroid group (odds ratio = 3.444, 95% confidence interval (CI: 1.570–7.553. Serum TSH was significantly positively correlated with waist circumference (β = 1.512, P = 0.019, TC (β = 0.160, P = 0.003, LDL-C (β = 0.032, P = 0.008, and TG (β = 0.095, P = 0.001. The TSH level in the metabolic syndrome group was significantly higher than that in nonmetabolic syndrome group (2.65 [2.28–3.80] versus 2.53 [1.92–3.45] mIU/L, P = 0.032. Serum TSH within the reference range was positively associated with TC (β = 0.173, P = 0.013, LDL-C (β = 0.031, P = 0.043, and TG (β = 0.132, P = 0.021. Increased serum TSH in adolescents may be a potential risk factor for metabolic syndrome.

  4. Carbohydrate chains of human thyrotropin are differentially susceptible to endoglycosidase removal on combined and free polypeptide subunits

    International Nuclear Information System (INIS)

    Ronin, C.; Papandreou, M.; Canonne, C.; Weintraub, B.D.

    1987-01-01

    The accessibility of the asparagine-linked carbohydrate chains of human thyrotropin (hTSH) and free α and β subunits was investigated by their susceptibility to endoglycosidases H and F as well as to peptide:N-glycosidase F. Iodinated hTSH or subunits were incubated with a commercial enzyme preparation containing both endoglycosidase F and N-glycosidase F activities and further analyzed by sodium dodecyl sulfate gel electrophoresis followed by quantitative autoradiography. The authors show that, working at the optimum of the N-glycosidase activity, the relative amount of endoglycosidase required for half-deglycosylation was 20-fold higher for native hTSH than for the reduced and dissociated subunits. Under nondenaturing conditions, the 18K β subunit of hTSH could be readily deglycosylated to a 14K species while the 22K α subunit was largely resistant. However, both subunits were converted to an apoprotein of similar apparent molecular weight of 14K following reduction of disulfide bonds. In contrast, the free α subunit of human choriogonadotropin appeared fully sensitive to carbohydrate removal under nonreducing conditions despite the presence of a partially deglycosylated 18K intermediate at low concentration of endoglycosidase. Similarly, both hTSH-α and hTSH-β could be completely deglycosylated after acid dissociation of the native hormone. While all three carbohydrate chains of hTSH are sensitive to pure peptide:N-glycosidase F, only one on α and the single oligosaccharide present on β in hTSH appeared to be cleaved by pure endoglycosidase F. These findings indicate that while the carbohydrate chain on β is not involved in αΒ association, the oligosaccharides on α are hindered when hTSH subunits are combined

  5. Clinical effects of thyrotropin-releasing hormone for severe epilepsy in childhood: a comparative study with ACTH therapy.

    Science.gov (United States)

    Matsumoto, A; Kumagai, T; Takeuchi, T; Miyazaki, S; Watanabe, K

    1987-01-01

    We investigated the effects and side effects of thyrotropin-releasing hormone (TRH) on severely epileptic children to evaluate the clinical usefulness of TRH in the treatment of epilepsy and compared them with the results of ACTH therapy. The subjects were 64 patients admitted consecutively between 1980 and 1986. Their seizures were frequent, more than one a day or more than one a week. The subjects were divided into two groups; 33 patients treated with ACTH and 31 treated with TRH. The mean follow-up periods in TRH and ACTH therapy were 8 months and 3.0 years, respectively. The daily dose of TRH-t 0.5-1 mg was administered intravenously (i.v.) or intramuscularly (i.m.) for 1-4 weeks. The follow-up periods were 3-12 months (mean 6 months). In the TRH group, complete control of seizures was achieved in 7 of 13 (53.7%) of those with infantile spasms, and marked improvement of EEGs were observed in 8 of 13 (61.5%) of them. In the ACTH group, seizure cessation was observed in 75% of infantile spasms. Of the patients who received ACTH, 66.7% had various side effects, including pneumonia, huge subcutaneous abscess, hypokalemia, cataracts, and brain shrinkage as shown on computed tomography (CT), whereas only 16.7% of the patients treated with TRH had transient reduction of urine volume without other laboratory and physical abnormalities. The results of the study indicated that some patients who received TRH had cessation of infantile spasms and improved EEG findings with no serious side effect. Because of the untoward side effects of ACTH therapy, TRH is considered a possible new treatment for children with infantile spasms.

  6. A Placebo-Controlled, Blinded and Randomised Study on the Effects of Recombinant Human Thyrotropin on Quality of Life in the Treatment of Thyroid Cancer

    DEFF Research Database (Denmark)

    Nygaard, Birte; Bastholt, Lars; Bennedbæk, Finn Noe

    2013-01-01

    BACKGROUND: It is well known that thyroid hormone withdrawal (THW) in thyroid cancer patients can induce a decrease in quality of life (QOL). Recombinant human thyrotropin (rh-TSH) has been used to avoid this; however, no blinded studies have ever documented the effect. OBJECTIVE: To compare QOL...... in patients with differentiated thyroid cancer (DTC) treated with either rh-TSH or liothyronine (L-T3) THW for 10 days. STUDY DESIGN: Double-blind, randomised cross-over. PATIENTS: Fifty-six patients with DTC treated by total thyroidectomy and indication for postsurgery radioiodine (RI) ablation therapy...

  7. Compounds from Ageratum conyzoides: isolation, structural elucidation and insecticidal activity.

    Science.gov (United States)

    Moreira, Márcio D; Picanço, Marcelo C; Barbosa, Luiz Cláudio A; Guedes, Raul Narciso C; Barros, Emerson C; Campos, Mateus R

    2007-06-01

    This work aimed at identifying plant compounds with insecticidal activity against Diaphania hyalinata (L.) (Lepidoptera: Pyralidae), Musca domestica (L.) (Diptera: Muscidae), Periplaneta americana (L.) (Blattodea: Blattidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetaefolia L.), Jimson weed (Datura stramonium L.), 'baleeira' herb (Cordia verbenaceae L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.) and billy goat weed (Ageratum conyzoides L.). Firstly, the insecticidal activities of hexane and ethanol plant extracts were evaluated against adults of R. dominica. Among them, only the hexane extract of A. conyzoides showed insecticidal activity. The hexane extract of this plant species was therefore fractionated by silica gel column chromatography to isolate and purify its bioactive chemical constituents. Three compounds were identified using IR spectra, (1)H NMR, (13)C NMR, HMBC and NOE after gel chromatography: 5,6,7,8,3', 4', 5'-heptamethoxyflavone, 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone and coumarin. The complete assignment of (13)C NMR to 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone was successfully made for the first time. 5,6,7,8,3'-Pentamethoxy-4', 5'-methylenedioxyflavone did not show any insecticidal activity against the four insect species tested. 5,6,7,8,3', 4', 5'-Heptamethoxyflavone showed low activity against D. hyalinata and R. dominica and was not toxic to M. domestica or P. americana. In contrast, coumarin showed insecticidal activity against all four insect pest species tested, with the following order of susceptibility: R. dominica < P. americana < D. hyalinata < M. domestica after 24 h exposure. Copyright 2007 Society of Chemical Industry.

  8. Isolation and structure elucidation of a neuropeptide from three ...

    African Journals Online (AJOL)

    The corpora cardiaca of three Namib Desert beetles, Onymacris plana, O. rugatipennis and Physadesmia globosa (family Tenebrionidae), contain hyperlipaemic and/or hypertrehalosaemic factors as shown by heterologous bioassays in migratory locusts and American cockroaches. The compounds have been isolated by ...

  9. Elucidating reaction mechanisms on quantum computers.

    Science.gov (United States)

    Reiher, Markus; Wiebe, Nathan; Svore, Krysta M; Wecker, Dave; Troyer, Matthias

    2017-07-18

    With rapid recent advances in quantum technology, we are close to the threshold of quantum devices whose computational powers can exceed those of classical supercomputers. Here, we show that a quantum computer can be used to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical computer simulations used to probe these reaction mechanisms, to significantly increase their accuracy and enable hitherto intractable simulations. Our resource estimates show that, even when taking into account the substantial overhead of quantum error correction, and the need to compile into discrete gate sets, the necessary computations can be performed in reasonable time on small quantum computers. Our results demonstrate that quantum computers will be able to tackle important problems in chemistry without requiring exorbitant resources.

  10. Does neuroimaging of suggestion elucidate hypnotic trance?

    Science.gov (United States)

    Raz, Amir

    2011-07-01

    Contemporary studies in the cognitive neuroscience of attention and suggestion shed new light on the underlying neural mechanisms that operationalize these effects. Without adhering to important caveats inherent to imaging of the living human brain, however, findings from brain imaging studies may enthrall more than explain. Scholars, practitioners, professionals, and consumers must realize that the influence words exert on focal brain activity is measurable but that these measurements are often difficult to interpret. While recent brain imaging research increasingly incorporates variations of suggestion and hypnosis, correlating overarching hypnotic experiences with specific brain substrates remains tenuous. This article elucidates the mounting role of cognitive neuroscience, including the relative merits and intrinsic limitations of neuroimaging, in better contextualizing trance-like concepts.

  11. Elucidating reaction mechanisms on quantum computers

    Science.gov (United States)

    Reiher, Markus; Wiebe, Nathan; Svore, Krysta M.; Wecker, Dave; Troyer, Matthias

    2017-01-01

    With rapid recent advances in quantum technology, we are close to the threshold of quantum devices whose computational powers can exceed those of classical supercomputers. Here, we show that a quantum computer can be used to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical computer simulations used to probe these reaction mechanisms, to significantly increase their accuracy and enable hitherto intractable simulations. Our resource estimates show that, even when taking into account the substantial overhead of quantum error correction, and the need to compile into discrete gate sets, the necessary computations can be performed in reasonable time on small quantum computers. Our results demonstrate that quantum computers will be able to tackle important problems in chemistry without requiring exorbitant resources. PMID:28674011

  12. Cardiac Effects of Thyrotropin Oversuppression with Levothyroxine in Young Women with Differentiated Thyroid Cancer

    Directory of Open Access Journals (Sweden)

    Kyung-Soon Hong

    2016-01-01

    Full Text Available Background. We investigated the cardiac effects of TSH (thyroid-stimulating hormone oversuppression in women with thyroidectomized differentiated thyroid cancer (DTC during levothyroxine suppression therapy. Methods. Fourteen young female patients with DTC were enrolled. The duration of TSH-suppressive therapy was 5 to 9 years. They satisfied the following criteria: (1 a serum level of TSH < 0.1 mU/L in the intermediate-risk or TSH < 0.3 mU/L in the low-recurrence-risk group and (2 having been receiving a fixed dose of LT4 before the study. Controls matched for age, sex, and body mass index (BMI were compared in terms of the levels of serum free T4, free T3, TSH, plasma N-terminal pro-brain natriuretic peptide (NT-pro-BNP, and cardiac functions and structures. Results. DTC patients and control subjects were well matched in heart rate and blood pressure. There were marked differences in serum TSH (P=0.001 and free T4 (P=0.002. However, there were no differences between the groups in serum free T3 and plasma NT-pro-BNP. Furthermore, there were nonsignificant differences in cardiac functions and structures between the groups. Conclusions. This study shows that TSH suppression therapy in women with DTC may be safe with respect to cardiac functions and structures despite intermittent oversuppression of TSH during long-term suppressive therapy. Trial Registration. This trial is registered with clinicaltrials.gov identifier NCT02645786.

  13. Elucidation of the mechanism for anomalous blueshift

    International Nuclear Information System (INIS)

    Kotaki, Hideyuki; Kando, Masaki; Koga, J.K.; Nakajima, Kazuhisa

    2004-01-01

    The anomalous blue shift of high intensity laser which was discovered by the present authors occurs in the process of gas ionization accompanied with the self-focusing. This shift does not depend either on the laser power or on the gas density and all photons are shifted by a certain frequency, while the one which has been known in common depends on both the intensity and density and only some part of the laser photons is shifted. In order to elucidate this phenomenon, the occurrence conditions of the anomalous blue shift were investigated and the results are compared with theory. The shifts were measured by focusing the laser beam in the gas-filled chamber with an off-axis-parabolic mirror and with a convex lens. When the reflective lens was used the amount of the shift depended significantly on the ionization rate of the plasma, while it depended on the pulse width when the transmission lens was used indicating that the shift is determined by the valence due to the ionization at the focusing point. (S. Funahashi)

  14. Biochemical research elucidating metabolic pathways in Pneumocystis*

    Directory of Open Access Journals (Sweden)

    Kaneshiro E.S.

    2010-12-01

    Full Text Available Advances in sequencing the Pneumocystis carinii genome have helped identify potential metabolic pathways operative in the organism. Also, data from characterizing the biochemical and physiological nature of these organisms now allow elucidation of metabolic pathways as well as pose new challenges and questions that require additional experiments. These experiments are being performed despite the difficulty in doing experiments directly on this pathogen that has yet to be subcultured indefinitely and produce mass numbers of cells in vitro. This article reviews biochemical approaches that have provided insights into several Pneumocystis metabolic pathways. It focuses on 1 S-adenosyl-L-methionine (AdoMet; SAM, which is a ubiquitous participant in numerous cellular reactions; 2 sterols: focusing on oxidosqualene cyclase that forms lanosterol in P. carinii; SAM:sterol C-24 methyltransferase that adds methyl groups at the C-24 position of the sterol side chain; and sterol 14α-demethylase that removes a methyl group at the C-14 position of the sterol nucleus; and 3 synthesis of ubiquinone homologs, which play a pivotal role in mitochondrial inner membrane and other cellular membrane electron transport.

  15. Tumour dosimetry and response in patients with metastatic differentiated thyroid cancer using recombinant human thyrotropin before radioiodine therapy

    Energy Technology Data Exchange (ETDEWEB)

    Keizer, Bart de; Hoekstra, Anne; Rijk, Peter P. van; Klerk, John M.H. de [Department of Nuclear Medicine, Room E02.222, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht (Netherlands); Brans, Boudewijn; Dierckx, Rudi A. [Department of Nuclear Medicine, Ghent University Hospital, Ghent (Belgium); Zelissen, Pierre M.J.; Koppeschaar, Hans P.F.; Lips, Cees J.M. [Department of Endocrinology, University Medical Center Utrecht (Netherlands)

    2003-03-01

    The development of recombinant human thyrotropin (rhTSH) has given clinicians new options for diagnostic follow-up and treatment of patients with differentiated thyroid cancer (DTC). This paper evaluates the tumour dosimetry and response following -iodine-131 treatment of metastatic thyroid cancer patients after rhTSH stimulation instead of classical hormone withdrawal-induced hypothyroidism. Nineteen consecutive {sup 131}I treatments in 16 patients were performed after rhTSH stimulation. All patients had undergone a near-total thyroidectomy followed by an ablative dosage of {sup 131}I. They all suffered from metastatic or recurrent disease showing tumoral {sup 131}I uptake on previous post-treatment scintigraphy. Dosimetric calculations were performed using {sup 131}I tumour uptake measurements from post-treatment {sup 131}I scintigrams and tumour volume estimations from radiological images. Response was assessed by comparing pre-treatment serum thyroglobulin (Tg) level with the Tg level 3 months post treatment. In 18 out of 19 treatments, uptake of {sup 131}I in metastatic or recurrent lesions was seen. The median tumour radiation dose was 26.3 Gy (range 1.3-368 Gy), and the median effective half-life was 2.7 days (range 0.5-6.5 days). Eleven of 19 treatments (10/16 patients) were evaluable for response after 3 months. {sup 131}I therapy with rhTSH resulted in a biochemical partial response in 3/11 or 27% of treatments (two patients), biochemical stable disease in 2/11 or 18% of treatments and biochemical progressive disease in 6/11 or 55% of treatments. Our study showed that although tumour doses in DTC patients treated with {sup 131}I after rhTSH were highly variable, 45% of treatments led to disease stabilisation or partial remission when using rhTSH in conjunction with {sup 131}I therapy, without serious side-effects and with minimal impact on quality of life. RhTSH is therefore adequately satisfactory as an adjuvant tool in therapeutic settings and is

  16. The influence of single low dose of recombinant human thyrotropin on I-131 treatment of large multi-nodular goitre

    International Nuclear Information System (INIS)

    Mojsak, M.N.; Abdelrazek, S.; Rogowski, F.; Szunowski, P.; Mysliwiec, J.; Kociura-Sawicka, A.

    2015-01-01

    Full text of publication follows. Recombinant human thyrotropin (rhTSH) is a substance that after single intramuscular injection can increase thyroid radioiodine uptake (RAIU) and improve the results of radioiodine therapy (RIT) in patients with nontoxic multi-nodular goitre (MNG). These effects are very important especially in cases of large MNG with relatively low RAIU or contraindications to surgery. The aim of the study: the evaluation of the influence of the single low dose of rhTSH to RAIU and the effects of RIT in patients with benign large nontoxic MNG. Material and methods: 40 patients (14 male, 26 female, age 41-80 yr) with large MNG > 100 grams and with baseline RAIU < 40% (33,37±7,96%) were included to the study and divided into two groups. First group received the single intramuscular injection of 0,03 mg rhTSH and the second received placebo. The RAIU were measured again 48 hours after the rhTSH (24 hours after diagnostic dose of I-131). After this, all the patients were administered the therapeutic doses of I-131 recalculated according to new RAIU. The patients follow up was continued for minimum 12 months. Results: the mean RAIU after rhTSH increased more than twice, to 75% from 33%. One year after RIT the mean volume goitre reduction were significantly greater in group with rhTSH than in patients with placebo (48±16% vs. 37±18%). Decrease of compression symptoms has taken place earlier and was more important in patients after rhTSH. 12 months after RIT two patients stay in hypothyroid state (from the group with rhTSH), other patients are euthyroid. Conclusions: even the single very low dose of rhTSH increases the values of RAIU in significant way. Efficacy of rhTSH-augmented RIT in patients with large nontoxic MNG is greater than standard RIT. It allows to reduce administered doses of I-131, decreases the need of repeating RIT, makes the radiation adsorbed doses for whole body lower and the RIT shorter. (authors)

  17. Inappropriate Suppression of Thyrotropin Concentrations in Young Patients with Thyroid Nodules Including Thyroid Cancer: The Fukushima Health Management Survey.

    Science.gov (United States)

    Suzuki, Satoru; Nakamura, Izumi; Suzuki, Satoshi; Ohkouchi, Chiyo; Mizunuma, Hiroshi; Midorikawa, Sanae; Fukushima, Toshihiko; Ito, Yuko; Shimura, Hiroki; Ohira, Tetsuya; Matsuzuka, Takashi; Ohtsuru, Akira; Abe, Masafumi; Yamashita, Shunichi; Suzuki, Shinichi

    2016-05-01

    Serum thyroid hormone concentration is regulated through the hypothalamic-pituitary-thyroid axis. This study aimed to clarify the relationships between thyroid hormone regulation and ultrasonographic findings in subjects with thyroid nodules detected during thyroid ultrasound examination for the Fukushima Health Management Survey. As of October 31, 2014, a total of 296,253 subjects, who had been living in Fukushima Prefecture at the time of the Fukushima nuclear power plant accident and were aged ≤18 years on March 11, 2011, participated in two concurrent screening programs. In the primary screening, thyroid nodules were detected in 2241 subjects. A secondary confirmatory thyroid ultrasound examination and blood sampling for thyroid function tests were performed on 2004 subjects. The subjects were reassessed and classified into disease-free subjects (Group 1), subjects with cysts only (Group 2), subjects with nodules (Group 3), and subjects with malignancy or suspected malignancy (Group 4). Serum concentrations of free triiodothyronine (fT3), free thyroxine (fT4), thyrotropin (TSH), thyroglobulin, and the fT3/fT4 ratio were classified according to the diagnoses. Inverse relationships between age and log TSH values (Spearman's correlation r = -0.311, p = 0.015), serum fT3 concentration (r = -0.688, p < 0.001), and the fT3/fT4 ratio (r = -0.520, p < 0.001) were observed in Group 1. When analysis of covariance with Bonferroni post hoc comparisons was used in the four groups, the log TSH values were significantly lower in both Group 3 and Group 4 compared with Group 1 and Group 2 after correcting for age (p < 0.001; Group 1 vs. Group 3, p = 0.016; Group 1 vs. Group 4, p = 0.022; Group 2 vs. Group 3, p = 0.001; Group 2 vs. Group 4, p = 0.008). However, no significant differences were observed between the four groups regarding levels of fT3, fT4, fT3/fT4 ratio, and thyroglobulin (p = 0.304, 0.340, 0.208, and 0

  18. Advances in applied homeostatic modelling of the relationship between thyrotropin and free thyroxine.

    Directory of Open Access Journals (Sweden)

    Rudolf Hoermann

    Full Text Available The relationship between pituitary TSH and thyroid hormones is central to our understanding of thyroid physiology and thyroid function testing. Here, we generated distribution patterns by using validated tools of thyroid modelling.We simulated patterns of individual set points under various conditions, based on a homeostatic model of thyroid feedback control. These were compared with observed data points derived from clinical trials.A random mix of individual set points was reconstructed by simulative modelling with defined structural parameters. The pattern displayed by the cluster of hypothetical points resembled that observed in a natural control group. Moderate variation of the TSH-FT4 gradient over the functional range introduced further flexibility, implementing a scenario of adaptive set points. Such a scenario may be a realistic possibility for instance in treatment where relationships and equilibria between thyroid parameters are altered by various influences such as LT4 dose and conversion efficiency.We validated a physiologically based homeostatic model that permits simulative reconstruction of individual set points. This produced a pattern resembling the observed data under various conditions. Applied modelling, although still experimental at this stage, shows a potential to aid our physiological understanding of the interplay between TSH and thyroid hormones. It should eventually benefit personalised clinical decision making.

  19. Differential regulation of thyrotropin subunit apoprotein and carbohydrate biosynthesis by thyroid hormone

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, T.; Weintraub, B.D.

    1985-04-01

    The regulation of TSH apoprotein and carbohydrate biosynthesis by thyroid hormone was studied by incubating pituitaries from normal and hypothyroid (3 weeks post-thyroidectomy) rats in medium containing (/sup 14/C)alanine and (/sup 3/H) glucosamine. After 6 h, samples were sequentially treated with anti-TSH beta to precipitate TSH and free TSH beta, anti-LH beta to clear the sample of LH and free LH beta, then anti-LH alpha to precipitate free alpha-subunit. Total proteins were acid precipitated. All precipitates were subjected to electrophoresis on sodium dodecyl sulfate-polyacrylamide gels, which were then sliced and assayed by scintillation spectrometry. In hypothyroid pituitaries plus medium, (/sup 14/C)alanine incorporation in combined and free beta-subunits was 26 times normal and considerably greater than the 3.4-fold increase seen in total protein; combined and free alpha-subunits showed no specific increase in apoprotein synthesis. (/sup 3/H)Glucosamine incorporation in combined alpha- and beta-subunits in hypothyroid samples was 13 and 21 times normal, respectively, and was greater than the 1.9-fold increase in total protein; free alpha-subunit showed no specific increase in carbohydrate synthesis. The glucosamine to alanine ratio, reflecting relative glycosylation of newly synthesized molecules, was increased in hypothyroidism for combined alpha-subunits, but not for combined beta-subunits, free alpha-subunits, or total proteins. In summary, short term hypothyroidism selectively stimulated TSH beta apoprotein synthesis and carbohydrate synthesis of combined alpha- and beta-subunits. Hypothyroidism also increased the relative glycosylation of combined alpha-subunit. Thus, thyroid hormone deficiency appears to alter the rate-limiting step in TSH assembly (i.e. beta-subunit synthesis) as well as the carbohydrate structure of TSH, which may play important roles in its biological function.

  20. Ensemble cryo-EM elucidates the mechanism of translation fidelity

    Science.gov (United States)

    Loveland, Anna B.; Demo, Gabriel; Grigorieff, Nikolaus; Korostelev, Andrei A.

    2017-01-01

    SUMMARY Faithful gene translation depends on accurate decoding, whose structural mechanism remains a matter of debate. Ribosomes decode mRNA codons by selecting cognate aminoacyl-tRNAs delivered by EF-Tu. We present high-resolution structural ensembles of ribosomes with cognate or near-cognate aminoacyl-tRNAs delivered by EF-Tu. Both cognate and near-cognate tRNA anticodons explore the A site of an open 30S subunit, while inactive EF-Tu is separated from the 50S subunit. A transient conformation of decoding-center nucleotide G530 stabilizes the cognate codon-anticodon helix, initiating step-wise “latching” of the decoding center. The resulting 30S domain closure docks EF-Tu at the sarcin-ricin loop of the 50S subunit, activating EF-Tu for GTP hydrolysis and ensuing aminoacyl-tRNA accommodation. By contrast, near-cognate complexes fail to induce the G530 latch, thus favoring open 30S pre-accommodation intermediates with inactive EF-Tu. This work unveils long-sought structural differences between the pre-accommodation of cognate and near-cognate tRNA that elucidate the mechanism of accurate decoding. PMID:28538735

  1. Diet elucidation: Supplementary inferences from mysid feeding ...

    African Journals Online (AJOL)

    Comparison of the structure of the feeding appendages of these two marine mysid species allows dietary inferences supplementing data derived from gut content analyses. Both species occur in abundance in the surf zone off sandy beaches where they contribute significantly to energy transfer through the food web.

  2. Experience in treating congenital hypothyroidism: implications regarding free thyroxine and thyrotropin steady-state concentrations during optimal levothyroxine treatment.

    Science.gov (United States)

    Bongers-Schokking, Jacoba J; de Ridder, Maria A J; de Rijke, Yolanda B; de Muinck Keizer-Schrama, Sabine M P F

    2013-02-01

    A major problem in the treatment of patients with congenital hypothyroidism (CHT) is that the optimal individual target values of thyrotropin (TSH) and free thyroxine (fT(4)) are unknown. We investigated whether patients with CHT have during treatment considered optimal stable fT(4) and TSH steady-state concentrations (SSCs) that can be used as target values, and whether TSH or fT(4) is more useful in guiding decisions regarding therapy. From 60 early-treated patients with CHT, TSH and fT(4) follow-up samples within the age interval 1.5-132 months (postinitial period) and within TSH interval 0.5-10 mU/L were selected. TSH and fT(4) SSCs were estimated by taking the individual mean values of a series of determinations, under the most euthyroid conditions possible (n=1257), for the whole age and TSH intervals, as well as for the age intervals 1.5-24, 25-72, and 73-132 months, as well as, for fT(4), for the two split TSH intervals 0.5-4.49 and 4.5-10 mU/L. For all SSCs, the within-subject coefficient of variation (CV(w)) was determined. Further, fT(4) SSCs were assessed for the first 6 weeks after therapy initiation. For both TSH and fT(4), individual SSCs differed significantly (p<0.001). The 95% confidence interval for TSH SSCs was 1.1-5.7 mU/L and for fT(4) SSCs 16.6-28.7 pmol/L. Mean CV(w) values for TSH and fT(4) SSCs were 60.9% and 13.1%, respectively. Individual fT(4) and TSH SSCs were reproducible when assessed for the three age intervals, both slightly decreasing with age (p≤0.033), and fT(4) SSCs were reproducible for the two split TSH intervals, with a slight fT(4) difference (p<0.001). fT(4) SSCs were largely independent of the administered LT(4) dosage (range 2.4-6.1 μg/kg). fT(4) SSCs of the initial period were comparable to those of postinitial period with a mean±SD difference of 1.0±3.5 pmol/L, p=0.07. Our study suggests that in CHT during therapy considered optimal, stable TSH and fT(4) SSCs can be found slightly decreasing with age and

  3. Is the incidence of differentiated thyroid cancer increased in patients with thyrotropin-secreting adenomas? Report of three cases from a large consecutive series.

    Science.gov (United States)

    Perticone, Francesca; Pigliaru, Francesca; Mariotti, Stefano; Deiana, Luca; Furlani, Lino; Mortini, Pietro; Losa, Marco

    2015-04-01

    Patients with a thyrotropin-secreting pituitary adenoma (TSHoma) are exposed to unregulated and inappropriately high levels of thyrotropin (TSH). Given the rarity of this condition, it is not known whether this chronic TSH stimulation of the thyroid gland might represent a risk factor for the development of differentiated thyroid cancer (DTC). We analyzed the incidence of DTC in a large cohort of patients with TSHomas. The study population consisted of all consecutive patients who underwent neurosurgery for a TSHoma between 1990 and 2013. Criteria for the diagnosis of TSHoma in patients without previous thyroid ablative procedures included elevated free thyroid hormones and normal/high serum TSH concentrations, presence of a lesion at magnetic resonance imaging (MRI), and abnormal response of TSH to at least one dynamic test. Patients who had received thyroid ablative procedures were required to have a pituitary lesion on MRI and TSH levels not suppressed while on levothyroxine therapy at doses causing elevation of free thyroid hormone levels. Sixty-two patients (32 females, 30 males) underwent surgery for a TSHoma at our center. Among them, 3 patients had a coexistent diagnosis of DTC with an estimated incidence of 4.8%. In 2 patients, DTC was diagnosed during the evaluation for suspected TSH-dependent hyperthyroidism, whereas in the third patient, diagnosis of DTC preceded the detection of the pituitary tumor. The elevated incidence of DTC in patients with TSHoma suggests a possible role of TSH hypersecretion in the development of thyroid tumors. A formal high-resolution ultrasound of the thyroid is recommended in patients diagnosed with a TSHoma, especially if a long history of the pituitary tumor is suspected. Moreover, suspicion about the presence of TSHoma should be raised by the lack of suppression of TSH levels despite adequate doses of levothyroxine after thyroidectomy for DTC.

  4. Receptors for thyrotropin-releasing hormone, thyroid-stimulating hormone, and thyroid hormones in the macaque uterus: effects of long-term sex hormone treatment.

    Science.gov (United States)

    Hulchiy, Mariana; Zhang, Hua; Cline, J Mark; Hirschberg, Angelica Lindén; Sahlin, Lena

    2012-11-01

    Thyroid gland dysfunction is associated with menstrual cycle disturbances, infertility, and increased risk of miscarriage, but the mechanisms are poorly understood. However, little is known about the regulation of these receptors in the uterus. The aim of this study was to determine the effects of long-term treatment with steroid hormones on the expression, distribution, and regulation of the receptors for thyrotropin-releasing hormone (TRHR) and thyroid-stimulating hormone (TSHR), thyroid hormone receptor α1/α2 (THRα1/α2), and THRβ1 in the uterus of surgically menopausal monkeys. Eighty-eight cynomolgus macaques were ovariectomized and treated orally with conjugated equine estrogens (CEE; n = 20), a combination of CEE and medroxyprogesterone acetate (MPA; n = 20), or tibolone (n = 28) for 2 years. The control group (OvxC; n = 20) received no treatment. Immunohistochemistry was used to evaluate the protein expression and distribution of the receptors in luminal epithelium, glands, stroma, and myometrium of the uterus. Immunostaining of TRHR, TSHR, and THRs was detected in all uterine compartments. Epithelial immunostaining of TRHR was down-regulated in the CEE + MPA group, whereas in stroma, both TRHR and TSHR were increased by CEE + MPA treatment as compared with OvxC. TRHR immunoreactivity was up-regulated, but THRα and THRβ were down-regulated, in the myometrium of the CEE and CEE + MPA groups. The thyroid-stimulating hormone level was higher in the CEE and tibolone groups as compared with OvxC, but the level of free thyroxin did not differ between groups. All receptors involved in thyroid hormone function are expressed in monkey uterus, and they are all regulated by long-term steroid hormone treatment. These findings suggest that there is a possibility of direct actions of thyroid hormones, thyroid-stimulating hormone and thyrotropin-releasing hormone on uterine function.

  5. An inverse approach for elucidating dendritic function

    Directory of Open Access Journals (Sweden)

    Benjamin Torben-Nielsen

    2010-09-01

    Full Text Available We outline an inverse approach for investigating dendritic function-structure relationships by optimizing dendritic trees for a-priori chosen computational functions. The inverse approach can be applied in two different ways. First, we can use it as a `hypothesis generator' in which we optimize dendrites for a function of general interest. The optimization yields an artificial dendrite that is subsequently compared to real neurons. This comparison potentially allows us to propose hypotheses about the function of real neurons. In this way, we investigated dendrites that optimally perform input-order detection. Second, we can use it as a `function confirmation' by optimizing dendrites for functions hypothesized to be performed by classes of neurons. If the optimized, artificial, dendrites resemble the dendrites of real neurons the artificial dendrites corroborate the hypothesized function of the real neuron. Moreover, properties of the artificial dendrites can lead to predictions about yet unmeasured properties. In this way, we investigated wide-field motion integration performed by the VS cells of the fly visual system. In outlining the inverse approach and two applications, we also elaborate on the nature of dendritic function. We furthermore discuss the role of optimality in assigning functions to dendrites and point out interesting future directions.

  6. Building blocks for automated elucidation of metabolites: natural product-likeness for candidate ranking.

    Science.gov (United States)

    Jayaseelan, Kalai Vanii; Steinbeck, Christoph

    2014-07-05

    In metabolomics experiments, spectral fingerprints of metabolites with no known structural identity are detected routinely. Computer-assisted structure elucidation (CASE) has been used to determine the structural identities of unknown compounds. It is generally accepted that a single 1D NMR spectrum or mass spectrum is usually not sufficient to establish the identity of a hitherto unknown compound. When a suite of spectra from 1D and 2D NMR experiments supplemented with a molecular formula are available, the successful elucidation of the chemical structure for candidates with up to 30 heavy atoms has been reported previously by one of the authors. In high-throughput metabolomics, usually 1D NMR or mass spectrometry experiments alone are conducted for rapid analysis of samples. This method subsequently requires that the spectral patterns are analyzed automatically to quickly identify known and unknown structures. In this study, we investigated whether additional existing knowledge, such as the fact that the unknown compound is a natural product, can be used to improve the ranking of the correct structure in the result list after the structure elucidation process. To identify unknowns using as little spectroscopic information as possible, we implemented an evolutionary algorithm-based CASE mechanism to elucidate candidates in a fully automated fashion, with input of the molecular formula and 13C NMR spectrum of the isolated compound. We also tested how filters like natural product-likeness, a measure that calculates the similarity of the compounds to known natural product space, might enhance the performance and quality of the structure elucidation. The evolutionary algorithm is implemented within the SENECA package for CASE reported previously, and is available for free download under artistic license at http://sourceforge.net/projects/seneca/. The natural product-likeness calculator is incorporated as a plugin within SENECA and is available as a GUI client and

  7. Elucidating the neurotoxic effects of MDMA and its analogs.

    Science.gov (United States)

    Karuppagounder, Senthilkumar S; Bhattacharya, Dwipayan; Ahuja, Manuj; Suppiramaniam, Vishnu; Deruiter, Jack; Clark, Randall; Dhanasekaran, Muralikrishnan

    2014-04-17

    There is a rapid increase in the use of methylenedioxymethamphetamine (MDMA) and its structural congeners/analogs globally. MDMA and MDMA-analogs have been synthesized illegally in furtive dwellings and are abused due to its addictive potential. Furthermore, MDMA and MDMA-analogs have shown to have induced several adverse effects. Hence, understanding the mechanisms mediating this neurotoxic insult of MDMA-analogs is of immense importance for the public health in the world. We synthesized and investigated the neurotoxic effects of MDMA and its analogs [4-methylenedioxyamphetamine (MDA), 2, 6-methylenedioxyamphetamine (MDMA), and N-ethyl-3, 4-methylenedioxyamphetamine (MDEA)]. The stimulatory or the dopaminergic agonist effects of MDMA and MDMA-analogs were elucidated using the established 6-hydroxydopamine lesioned animal model. Additionally, we also investigated the neurotoxic mechanisms of MDMA and MDMA-analogs on mitochondrial complex-I activity and reactive oxygen species generation. MDMA and MDMA-analogs exhibited stimulatory activity as compared to amphetamines and also induced several behavioral changes in the rodents. MDMA and MDMA-analogs enhanced the reactive oxygen generation and inhibited mitochondrial complex-I activity which can lead to neurodegeneration. Hence the mechanism of neurotoxicity, MDMA and MDMA-analogs can enhance the release of monoamines, alter the monoaminergic neurotransmission, and augment oxidative stress and mitochondrial abnormalities leading to neurotoxicity. Thus, our study will help in developing effective pharmacological and therapeutic approaches for the treatment of MDMA and MDMA-analog abuse. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. STATUS SOSIAL-EKONOMI DAN KADAR HORMON TIROTROPIN RUMAH-TANGGA PENGGUNA GARAM BERIDOIUM DI PERKOTAAN INDONESIA : ANALISIS DATA RISKESDAS 2007 (SOCIO-ECONOMIC STATUS AND THYROTROPIN HORMONE LEVEL OF HOUSEHOLDS USING IODIZED SALT IN INDONESIAN URBAN : ANA

    Directory of Open Access Journals (Sweden)

    Djoko Kartono

    2012-12-01

    Full Text Available ABSTRACT Iodized salt is the long term and sustainable strategy to improve iodine intakeof the community.Level of thyroid stimulating hormone (thyrotropin hormone can be used as indicator of iodine intake adequacy. To study the socio-economic status of households using iodized salt and thyrotropin hormone level in urban areas. Riskesdas data 2007 that include 280.000 households was used.Thyrotropin hormone data include 9.457 people aged above 1 years. Variables included classification of village, rapid test on salt, education and occupation of households’ head, household expenditure and level of thyrotropin hormone. Around 80 percentof households where households’ head graduated from college/university used salt containing sufficient iodine. Only 18 percent households with households’ headworks as government workers used salt containing sufficient iodine. Around 70 percent households in 5th quintile of household’s expenditure were using salt with sufficient iodine content. Around 70 percent households in urban areas were using salt withsufficient iodine content.Among children 1-4 years, percentage of low category of thyrotropin hormon level was 3.3 percentand among 60 years of age and above was 15.8 percent. The higher the educational levelthe higher the percentage of households used salt with sufficient iodine. Percentage of households using salt with sufficient iodine was higher in urban than in rural areas. The higher the quintiles of household expenditures the higher the percentage of households using salt with sufficient iodine. There was a trend that the higher the age the higher the percentage of low category of thyrotropin hormone level. Keywords: householdsalt, education, occupation, urban, rural, expenditure, thyrotropin hormone   ABSTRAK Garam beriodium merupakan strategi jangka panjang dan berkesinambungan untuk memperbaiki asupan iodium masyarakat. Sementara itu, kadar thyroid stimulating hormone (hormon tirotropin dapat

  9. Synthetic Elucidation of Design Principles for Molecular Qubits

    Science.gov (United States)

    Graham, Michael James

    Quantum information processing (QIP) is an emerging computational paradigm with the potential to enable a vast increase in computational power, fundamentally transforming fields from structural biology to finance. QIP employs qubits, or quantum bits, as its fundamental units of information, which can exist in not just the classical states of 0 or 1, but in a superposition of the two. In order to successfully perform QIP, this superposition state must be sufficiently long-lived. One promising paradigm for the implementation of QIP involves employing unpaired electrons in coordination complexes as qubits. This architecture is highly tunable and scalable, however coordination complexes frequently suffer from short superposition lifetimes, or T2. In order to capitalize on the promise of molecular qubits, it is necessary to develop a set of design principles that allow the rational synthesis of complexes with sufficiently long values of T2. In this dissertation, I report efforts to use the synthesis of series of complexes to elucidate design principles for molecular qubits. Chapter 1 details previous work by our group and others in the field. Chapter 2 details the first efforts of our group to determine the impact of varying spin and spin-orbit coupling on T2. Chapter 3 examines the effect of removing nuclear spins on coherence time, and reports a series of vanadyl bis(dithiolene) complexes which exhibit extremely long coherence lifetimes, in excess of the 100 mus threshold for qubit viability. Chapters 4 and 5 form two complimentary halves of a study to determine the exact relationship between electronic spin-nuclear spin distance and the effect of the nuclear spins on T2. Finally, chapter 6 suggests next directions for the field as a whole, including the potential for work in this field to impact the development of other technologies as diverse as quantum sensors and magnetic resonance imaging contrast agents.

  10. Effects of metamorphosis and captivity on the in vitro sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin

    International Nuclear Information System (INIS)

    Norman, M.F.; Norris, D.O.

    1987-01-01

    The sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin (bTSH) was tested in vitro. Thyroids were taken from subjects representing metamorphic stages I (premetamorphic larvae), II (onset of climax), and VII (completion of gill resorption), as well as from captivity control larvae. Exogenous TSH reduced the cumulative uptake of 125 I in vitro by thyroids from stage I larvae after 24 and 48 hr. The capacity of thyroids to release thyroxine (T4) in vitro was used subsequently as a measure of their responsiveness to TSH. Baseline levels of T4 release in vitro were variable but did not differ significantly among developmental stages. A low dose of bTSH (5 X 10(-6) IU/ml) did not increase in vitro T4 release compared with that of controls. A larger dose (5 X 10(-4) IU/ml) caused greater increases in T4 release from thyroids of stage II and VII subjects than from those of controls. This dose produced only a small response by thyroids from captivity-control subjects. The results suggest that the thyroids of Ambystoma increase in their capacity to respond to TSH during the process of metamorphosis

  11. Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin

    DEFF Research Database (Denmark)

    Dolva, L O; Welinder, B S; Hanssen, K F

    1983-01-01

    Thyrotropin-releasing hormone immunoreactivity (TRH-IR) was measured in isolated islets and in medium from rat pancreatic islets maintained in organ culture. TRH-IR in methanol extracts of both islets and culture medium was eluted in the same position as synthetic TRH by ion-exchange and gel......-IR into the culture medium was observed from islets of both 5-d-old (newborn) and 30-d-old (adult) rats with a maximum on the second day of culture (28.7 +/- 7.0 and 13.3 +/- 3.6 fmol/islet per d, respectively). The content of TRH-IR was higher in freshly isolated islets from newborn rats (22.4 +/- 2.3 fmol....../islet) than in adult rat islets, which, however, increased their content from 1.3 +/- 0.5 to 7.0 +/- 0.5 fmol/islet during the first 3 d of culture. Adult rat islets maintained in medium with 20 mM glucose released significantly more TRH-IR than islets in 3.3 mM glucose medium (13.0 +/- 0.7 vs. 4.3 +/- 0...

  12. Thyroid stimulation with recombinant human thyrotropin in healthy cats, cats with non-thyroidal illness and in cats with low serum thyroxin and azotaemia after treatment of hyperthyroidism.

    Science.gov (United States)

    van Hoek, Ingrid M; Vandermeulen, Eva; Peremans, Kathelijne; Daminet, Sylvie

    2010-02-01

    This study investigated the recombinant human thyrotropin (rhTSH) stimulation test in healthy cats (group 1), cats with non-thyroidal illness (group 2) and cats with low serum total T(4) (TT(4)) and azotaemia after (131)I treatment (group 3). Serum TT(4) responses and thyroidal pertechnetate uptake after administration of 25 microg rhTSH IV were assessed. Baseline serum TT(4) was significantly lower in group 3 compared with group 1, but not between other group pairs. Serum TT(4) increased significantly in groups 1 and 2 but not in group 3 after rhTSH administration. Post-rhTSH serum TT(4) concentrations differed significantly between groups 1 and 3 and groups 2 and 3, but not between groups 1 and 2. Thyroid/salivary gland uptake ratio (T/S uptake ratio) differed only significantly between groups 1 and 3. Stimulation with rhTSH is valuable to differentiate euthyroidism from iatrogenic hypothyroidism in cats. Copyright 2009 ESFM and AAFP. Published by Elsevier Ltd. All rights reserved.

  13. Elucidation of the biosynthesis of meroterpenoid yanuthone D in Aspergillus Niger

    DEFF Research Database (Denmark)

    Holm, Dorte Koefoed; Petersen, Lene Maj; Klitgaard, Andreas

    2012-01-01

    We have elucidated the mode of biosynthesis of the meroterpenoid compound Yanuthone D in Aspergillus niger. We have successfully deleted all cluster genes, and identified a number of intermediates. Structures of the intermediates were solved using a combined approach comprising classical 1D- and ......-NMR and tandem mass spectrometry (MS/MS). In this study we have confirmed that Yanuthone D is of meroterpenoid origin, and we have identified an unexpected precursor, which has not before been reported for Aspergillus niger....

  14. Elucidation and in planta reconstitution of the parthenolide biosynthetic pathway

    DEFF Research Database (Denmark)

    Liu, Qing; Manzano, David; Tanić, Nikola

    2014-01-01

    Parthenolide, the main bioactive compound of the medicinal plant feverfew (Tanacetum parthenium), is a promising anti-cancer drug. However, the biosynthetic pathway of parthenolide has not been elucidated yet. Here we report on the isolation and characterization of all the genes from feverfew tha...

  15. Elucidation of physico-chemical characteristics and mycoflora of ...

    African Journals Online (AJOL)

    Elucidation of physico-chemical characteristics and mycoflora of bovine milk available in selected area of Karachi, Pakistan. ... The concentrations of metals considered were estimated after wet digestion of samples using atomic absorption spectroscopy. The ranges of average concentration of Mg, Fe, Cu and Zn were found ...

  16. Elucidation and in planta reconstitution of the parthenolide biosynthetic pathway

    NARCIS (Netherlands)

    Liu, Q.; Manzano, D.; Tanic, N.; Pesic, M.; Bankovic, J.; Pateraki, I.; Ricard, L.; Ferrer, A.; Vos, de R.C.H.; Krol, van der A.R.; Bouwmeester, H.J.

    2014-01-01

    Parthenolide, the main bioactive compound of the medicinal plant feverfew (Tanacetum parthenium), is a promising anti-cancer drug. However, the biosynthetic pathway of parthenolide has not been elucidated yet. Here we report on the isolation and characterization of all the genes from feverfew that

  17. How selective are the new guidelines for treatment of subclinical hypothyroidism for patients with thyrotropin levels at or below 10 mIU/L?

    Science.gov (United States)

    Rosario, Pedro Weslley; Calsolari, Maria Regina

    2013-05-01

    By consensus, a thyrotropin (TSH) level persistently >10 mIU/L is an indication for the treatment of subclinical hypothyroidism (SCH). Controversy exists regarding patients whose TSH level is elevated but Thyroid Association (ATA) and the American Association of Clinical Endocrinologists (AACE) published their position about factors that should be considered in the decision on treating SCH. This study evaluated the frequency of these factors among adult (non-pregnant) women with SCH whose TSH levels are ≤10 mIU/L. The presence of the conditions that should be considered for the treatment of SCH according to ATA and AACE was evaluated in 252 women who were diagnosed with SCH and had TSH levels ≤10 mIU/L. Pregnant women were excluded. Antithyroperoxidase antibodies (TPOAbs) were detected in 137 (54.3%) women. A high cardiovascular risk was observed in 43 (17%) women. Eighty (31.7%) women who were not at high cardiovascular risk presented at least one classical risk factor (arterial hypertension, elevated level of low-density lipoprotein-cholesterol or low level of high-density lipoprotein-cholesterol, smoking, or first-degree family history of premature coronary artery disease). At least one symptom or sign of hypothyroidism that could not be explained by another condition was observed in 180 (71.4%) women. Two hundred thirty-two (92%) women had positive TPOAbs, or at least one classical cardiovascular risk factor, or at least one symptom or sign of hypothyroidism. According to the new ATA and AACE guidelines, L-T4 therapy would be considered for 92% of women with SCH and TSH ≤10 mIU/L.

  18. L-type calcium channels and MAP kinase contribute to thyrotropin-releasing hormone-induced depolarization in thalamic paraventricular nucleus neurons.

    Science.gov (United States)

    Kolaj, Miloslav; Zhang, Li; Renaud, Leo P

    2016-06-01

    In rat paraventricular thalamic nucleus (PVT) neurons, activation of thyrotropin-releasing hormone (TRH) receptors enhances neuronal excitability via concurrent decrease in a G protein-coupled inwardly rectifying K (GIRK)-like conductance and opening of a cannabinoid receptor-sensitive transient receptor potential canonical (TRPC)-like conductance. Here, we investigated the calcium (Ca(2+)) contribution to the components of this TRH-induced response. TRH-induced membrane depolarization was reduced in the presence of intracellular BAPTA, also in media containing nominally zero [Ca(2+)]o, suggesting a critical role for both intracellular Ca(2+) release and Ca(2+) influx. TRH-induced inward current was unchanged by T-type Ca(2+) channel blockade, but was decreased by blockade of high-voltage-activated Ca(2+) channels (HVACCs). Both the pharmacologically isolated GIRK-like and the TRPC-like components of the TRH-induced response were decreased by nifedipine and increased by BayK8644, implying Ca(2+) influx via L-type Ca(2+) channels. Only the TRPC-like conductance was reduced by either thapsigargin or dantrolene, suggesting a role for ryanodine receptors and Ca(2+)-induced Ca(2+) release in this component of the TRH-induced response. In pituitary and other cell lines, TRH stimulates MAPK. In PVT neurons, only the GIRK-like component of the TRH-induced current was selectively decreased in the presence of PD98059, a MAPK inhibitor. Collectively, the data imply that TRH-induced depolarization and inward current in PVT neurons involve both a dependency on extracellular Ca(2+) influx via opening of L-type Ca(2+) channels, a sensitivity of a TRPC-like component to intracellular Ca(2+) release via ryanodine channels, and a modulation by MAPK of a GIRK-like conductance component. Copyright © 2016 the American Physiological Society.

  19. Tripeptide amide L-pyroglutamyl-histidyl-L-prolineamide (L-PHP-thyrotropin-releasing hormone, TRH) promotes insulin-producing cell proliferation.

    Science.gov (United States)

    Luo, LuGuang; Luo, John Z Q; Jackson, Ivor

    2013-02-01

    A very small tripeptide amide L-pyroglutamyl-L-histidyl-L-prolineamide (L-PHP, Thyrotropin-Releasing Hormone, TRH), was first identified in the brain hypothalamus area. Further studies found that L-PHP was expressed in pancreas. The biological role of pancreatic L-PHP is still not clear. Growing evidence indicates that L-PHP expression in the pancreas may play a pivotal role for pancreatic development in the early prenatal period. However, the role of L-PHP in adult pancreas still needs to be explored. L-PHP activation of pancreatic β cell Ca2+ flow and stimulation of β-cell insulin synthesis and release suggest that L-PHP involved in glucose metabolism may directly act on the β cell separate from any effects via the central nervous system (CNS). Knockout L-PHP animal models have shown that loss of L-PHP expression causes hyperglycemia, which cannot be reversed by administration of thyroid hormone, suggesting that the absence of L-PHP itself is the cause. L-PHP receptor type-1 has been identified in pancreas which provides a possibility for L-PHP autocrine and paracrine regulation in pancreatic function. During pancreatic damage in adult pancreas, L-PHP may protect beta cell from apoptosis and initiate its regeneration through signal pathways of growth hormone in β cells. L-PHP has recently been discovered to affect a broad array of gene expression in the pancreas including growth factor genes. Signal pathways linked between L-PHP and EGF receptor phosphorylation suggest that L-PHP may be an important factor for adult β-cell regeneration, which could involve adult stem cell differentiation. These effects suggest that L-PHP may benefit pancreatic β cells and diabetic therapy in clinic.

  20. Effects of sodium ions on rat thyrocyte (FRTL-5 cells) swelling- and thyrotropin-activated taurine efflux dependent on cAMP and Epac.

    Science.gov (United States)

    Fugelli, Kjell

    2016-03-01

    Cellular osmolyte release is important in preventing water accumulation and swelling. However, the signaling pathways that detect volume increase and activate solute efflux are still not fully understood. We investigated efflux activation of the osmolyte taurine which is actively accumulated in rat thyrocytes (FRTL-5). Efflux of accumulated [(3)H]taurine was stimulated by cellular swelling and thyrotropin (TSH). These effects were significantly diminished in cells having reduced TSH receptor concentrations. Phosphodiesterase inhibitors (IBMX, Rolipram) enhanced both responses. An analog of forskolin (FSK; 7-deacetyl-7-[O-(N-methylpiperazino)-γ-butyryl] dihydrochloride) and an analog of cAMP, specific for activating exchange protein activated directly by cAMP (Epac; 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester), significantly stimulated [(3)H]taurine efflux. A cAMP analog specific for activating protein kinase A (PKA; N6-benzoyladenosine-3',5'-cyclic monophosphate, acetoxymethyl ester) had no significant stimulatory effect on [(3)H]taurine efflux rate. The amiloride analog, 5-(N-ethyl-N-isopropyl)-amiloride, which inhibits a TSH-stimulated Na(+)/H(+) exchanger, enhanced (100 %) and ouabain inhibited (50 %) the TSH-stimulated [(3)H]taurine efflux rate. The effect of FSK on efflux was strongly potentiated by Na(+)-free iso-osmotic conditions and by osmolality/cell volume that affected also the db-cAMP-stimulated efflux. The TSH receptors and downstream elements of the signaling pathway comprising adenylyl cyclase, cAMP and Epac appeared to mediate the hormone-induced signal for [(3)H]taurine efflux from FRTL-5 cells. With less evidence, the cell volume/osmolality-induced [(3)H]taurine efflux cascade appeared to share some of the hormone signaling elements and to modulate the hormone signaling pathway at two levels through cellular Na(+).

  1. Food-intake dysregulation in type 2 diabetic Goto-Kakizaki rats: hypothesized role of dysfunctional brainstem thyrotropin-releasing hormone and impaired vagal output.

    Science.gov (United States)

    Zhao, K; Ao, Y; Harper, R M; Go, V L W; Yang, H

    2013-09-05

    Thyrotropin-releasing hormone (TRH), a neuropeptide contained in neural terminals innervating brainstem vagal motor neurons, enhances vagal outflow to modify multisystemic visceral functions and food intake. Type 2 diabetes (T2D) and obesity are accompanied by impaired vagal functioning. We examined the possibility that impaired brainstem TRH action may contribute to the vagal dysregulation of food intake in Goto-Kakizaki (GK) rats, a T2D model with hyperglycemia and impaired central vagal activation by TRH. Food intake induced by intracisternal injection of TRH analog was reduced significantly by 50% in GK rats, compared to Wistar rats. Similarly, natural food intake in the dark phase or food intake after an overnight fast was reduced by 56-81% in GK rats. Fasting (48h) and refeeding (2h)-associated changes in serum ghrelin, insulin, peptide YY, pancreatic polypeptide and leptin, and the concomitant changes in orexigenic or anorexigenic peptide expression in the brainstem and hypothalamus, all apparent in Wistar rats, were absent or markedly reduced in GK rats, with hormone release stimulated by vagal activation, such as ghrelin and pancreatic polypeptide, decreased substantially. Fasting-induced Fos expression accompanying endogenous brainstem TRH action decreased by 66% and 91%, respectively, in the nucleus tractus solitarius (NTS) and the dorsal motor nucleus of the vagus (DMV) in GK rats, compared to Wistar rats. Refeeding abolished fasting-induced Fos-expression in the NTS, while that in the DMV remained in Wistar but not GK rats. These findings indicate that dysfunctional brainstem TRH-elicited vagal impairment contributes to the disturbed food intake in T2D GK rats, and may provide a pathophysiological mechanism which prevents further weight gain in T2D and obesity. Published by Elsevier Ltd.

  2. Elucidate Innovation Performance of Technology-driven Mergers and Acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L.; Wang, K.; Yu, H.; Shang, L.; Mitkova, L.

    2016-07-01

    The importance and value of Mergers and Acquisitions (M&As) have increased with the expectancy to obtain key technology capabilities and rapid impact on innovation. This article develops an original analytical framework to elucidate the impact of the technology and product relatedness (similarity/complementarity) of the Technology-driven M&A’ partners on post-innovation performance. We present results drawing on a multiple case studies of Chinese High-Tech firms from three industries. (Author)

  3. Building blocks for automated elucidation of metabolites: Machine learning methods for NMR prediction

    Directory of Open Access Journals (Sweden)

    Neumann Steffen

    2008-09-01

    Full Text Available Abstract Background Current efforts in Metabolomics, such as the Human Metabolome Project, collect structures of biological metabolites as well as data for their characterisation, such as spectra for identification of substances and measurements of their concentration. Still, only a fraction of existing metabolites and their spectral fingerprints are known. Computer-Assisted Structure Elucidation (CASE of biological metabolites will be an important tool to leverage this lack of knowledge. Indispensable for CASE are modules to predict spectra for hypothetical structures. This paper evaluates different statistical and machine learning methods to perform predictions of proton NMR spectra based on data from our open database NMRShiftDB. Results A mean absolute error of 0.18 ppm was achieved for the prediction of proton NMR shifts ranging from 0 to 11 ppm. Random forest, J48 decision tree and support vector machines achieved similar overall errors. HOSE codes being a notably simple method achieved a comparatively good result of 0.17 ppm mean absolute error. Conclusion NMR prediction methods applied in the course of this work delivered precise predictions which can serve as a building block for Computer-Assisted Structure Elucidation for biological metabolites.

  4. Chemical approaches to the elucidation of template biosynthesis: study of replication and reverse transcription

    Science.gov (United States)

    Knorre, Dmitrii G.; Kudryashova, Natal'ya V.; Lavrik, Ol'ga I.

    1998-05-01

    Chemical approaches to the elucidation of DNA template biosynthesis using DNA polymerases and reverse transcriptases, predominantly DNA polymerase I from E. coli and reverse transcriptase from HIV-1, are considered. Special attention is paid to the comparison of chemical modification and X-ray structural analysis data as well as to quantitative aspects of the interaction of DNA polymerases with templates, primers, and nucleoside 5'-triphosphates. New versions of a catalytically competent labelling method developed in the course of investigation of these enzymes are described. The data obtained in the analysis of replication complexes using primer analogues with photoreactive groups are presented. The bibliography includes 98 references.

  5. Elucidation of the biosynthesis of meroterpenoid yanuthone D in Aspergillus Niger

    DEFF Research Database (Denmark)

    Holm, Dorte Koefoed; Petersen, Lene Maj; Klitgaard, Andreas

    2012-01-01

    We have elucidated the mode of biosynthesis of the meroterpenoid compound Yanuthone D in Aspergillus niger. We have successfully deleted all cluster genes, and identified a number of intermediates. Structures of the intermediates were solved using a combined approach comprising classical 1D- and 2D......-NMR and tandem mass spectrometry (MS/MS). In this study we have confirmed that Yanuthone D is of meroterpenoid origin, and we have identified an unexpected precursor, which has not before been reported for Aspergillus niger....

  6. Chemical approaches to the elucidation of template biosynthesis: study of replication and reverse transcription

    International Nuclear Information System (INIS)

    Knorre, Dmitrii G; Kudryashova, Natal'ya V; Lavrik, Ol'ga I

    1998-01-01

    Chemical approaches to the elucidation of DNA template biosynthesis using DNA polymerases and reverse transcriptases, predominantly DNA polymerase I from E. coli and reverse transcriptase from HIV-1, are considered. Special attention is paid to the comparison of chemical modification and X-ray structural analysis data as well as to quantitative aspects of the interaction of DNA polymerases with templates, primers, and nucleoside 5'-triphosphates. New versions of a catalytically competent labelling method developed in the course of investigation of these enzymes are described. The data obtained in the analysis of replication complexes using primer analogues with photoreactive groups are presented. The bibliography includes 98 references.

  7. Diagnostic value of recombinant human thyrotropin-stimulated ¹²³I whole-body scintigraphy in the follow-up of patients with differentiated thyroid cancer.

    Science.gov (United States)

    Alzahrani, Ali S; AlShaikh, OmAlkhaire; Tuli, Mahmoud; Al-Sugair, Abdulaziz; Alamawi, Reem; Al-Rasheed, Maha M

    2012-03-01

    Published data on recombinant human thyrotropin- (rhTSH-) stimulated iodine-123 (¹²³I) diagnostic whole-body scintigraphy (DxWBS) in differentiated thyroid cancer (DTC) surveillance after initial treatment are limited. We sought to evaluate this modality's diagnostic value in this setting. We retrospectively compared rhTSH-stimulated ¹²³I DxWBS results with DTC status concurrently determined by stimulated serum thyroglobulin (Tg) measurement, neck ultrasonography, and other imaging studies. Disease was considered present based on stimulated Tg level ≥1 μg/L without interfering Tg autoantibodies with or without positive imaging or biopsy-proven DTC. We also compared scan positivity and disease detection rates of rhTSH-stimulated DxWBS scans obtained with ¹²³I with those acquired with iodine-131 (¹³¹I) during the same period. The sample comprised 105 consecutive totally thyroidectomized patients undergoing rhTSH-aided DxWBS with I-123 (n = 67) or with ¹³¹I (n = 38) for diagnostic follow-up. rhTSH, 0.9 mg/d, was injected intramuscularly on 2 consecutive days. Oral diagnostic activities of 5 to 10 mCi (185-370 MBq) ¹²³I or 3 mCi (111 MBq) ¹³¹I were given on the third day. DxWBS was performed 24 hours (¹²³I) or 48 to 72 hours (¹³¹I) later. rhTSH-aided ¹²³I DxWBS scans showed 35.3% sensitivity, 98.0% specificity, 85.7% positive predictive value, and 81.6% negative predictive value. rhTSH-stimulated ¹²³I and ¹³¹I DxWBS did not differ in scan positivity (10.4% vs. 13.2%, P = 0.75) or disease detection rates (35.3% vs. 27.8%, P = 1.00). In DTC, rhTSH-aided ¹²³I DxWBS achieves comparable results in diagnostic follow-up with those of rhTSH-aided ¹³¹I DxWBS. Future studies should address the preablation setting and scan activity and timing.

  8. Stable expression of human thyrotropin (hTSH) in mammalian cells (CHO) expressing α2,6 sialyltransferase

    International Nuclear Information System (INIS)

    Damiani, Renata

    2009-01-01

    A CHO cell line, previously genetically modified by the introduction of rat α2,6-sialyltransferase cDNA, generated for the first time a human-like sialylated recombinant hTSH (hlsr-hTSH) more similar to the native hormone, with 61% of α2,3- and 39% of α2,6-linked sialic acid residues. The best clone, when submitted to gene amplification with up to 8 μM methotrexate, presented a secretion level of ∼2 μg hTSH/10 6 cells/day, useful for product purification and characterization. The relative molecular masses (M r ) of the heterodimer and of the α- and β-subunits of purified hlsr-hTSH, determined by MALDI-TOF mass spectrometry, and the relative hydrophobicities, determined by RP-HPLC, were not remarkably different from those presented by two r-hTSH preparations secreted by normal CHO cells. Some differences were observed, though, in N-glycan composition, with more tri- and much more tetra-sialylated structures in hlsr-hTSH. When analyzed via an in vivo bioassay based on hTSH-induced T 4 release in mice, hlsr-hTSH was shown to be equipotent (p > 0.05) with the commercial preparation of r-hTSH (Thyrogen), and 1.5-fold more potent than native hTSH (p < 0.001). (author)

  9. Substructure elucidation and chemical shift estimation using the nuclear magnetic resonance spectral database

    International Nuclear Information System (INIS)

    Yamamoto, Osamu; Hayamizu, Kikuko; Yanagisawa, Masaru

    1989-01-01

    A computer system for substructure elucidation and chemical shift estimation by the use of nuclear magnetic resonance (NMR) spectra is described. In this system, substructures in a molecule can be elucidated by specifying chemical shift values or ranges, and conversely chemical shift values can be estimated by specifying substructures for both 1 H- and 13 C-NMR data. The retrieval of data can be performed interactively between 1 H- and 13 C-NMR data. It is possible to estimate all chemical shift values for a compound by giving its chemical structure. The search file for these purposes is created for signals (or signal groups) from a large number of 1 H- and 13 C-NMR spectra in our database. The information contained in the search file consists of substructures and the corresponding chemical shift values. A line notation system has been developed to plot chemical structures with spectral assignments of NMR signals and to extract substructures corresponding to particular chemical shift values. (author)

  10. Genetics and neuroimaging of attention and hypnotizability may elucidate placebo.

    Science.gov (United States)

    Raz, Amir

    2008-01-01

    Attention binds psychology to the techniques of neuroscience and exemplifies the links between brain and behavior. Associated with attentional networks, at least 3 brain modules govern control processes by drawing on disparate functional neuroanatomy, neuromodulators, and psychological substrates. Guided by data-driven brain theories, researchers have related specific genetic polymorphisms to well-defined phenotypes, including those associated with different attentional efficiencies and hypnosis. Because attention can modulate both cognitive and affective processes, genetic assays together with neuroimaging data have begun to elucidate individual differences. Findings from genetic assays of both attention and hypnotizability pave the way to answering questions such as how high hypnotizable individuals may differ from less-hypnotizable persons. These exploratory findings may extend to the identification of placebo responders.

  11. Elucidation of Isomerization Pathways of a Single Azobenzene Derivative Using an STM.

    Science.gov (United States)

    Kazuma, Emiko; Han, Mina; Jung, Jaehoon; Oh, Junepyo; Seki, Takahiro; Kim, Yousoo

    2015-11-05

    The predominant pathway for the isomerization between cis- and trans-azobenzenes-either (i) inversion by the bending of an NNC bond or (ii) rotation by the torsion of two phenyl rings-continues to be a controversial topic. To elucidate each isomerization pathway, a strategically designed and synthesized azobenzene derivative was investigated on a Ag(111) surface. This was achieved by exciting the molecule with tunneling electrons from the tip of a scanning tunneling microscope (STM). Structural analyses of the molecularly resolved STM images reveal that both inversion and rotation pathways are available for isomerization on a metal surface and strongly depend on the initial adsorption structures of the molecule. On the basis of the potential energy diagrams for the isomerization, it is concluded that isomerization pathways on a metal surface are not simply related to the excited states.

  12. Development of dielectrophoresis MEMS device for PC12 cell patterning to elucidate nerve-network generation

    Science.gov (United States)

    Nakamachi, Eiji; Koga, Hirotaka; Morita, Yusuke; Yamamoto, Koji; Sakamoto, Hidetoshi

    2018-01-01

    We developed a PC12 cell trapping and patterning device by combining the dielectrophoresis (DEP) methodology and the micro electro mechanical systems (MEMS) technology for time-lapse observation of morphological change of nerve network to elucidate the generation mechanism of neural network. We succeeded a neural network generation, which consisted of cell body, axon and dendrites by using tetragonal and hexagonal cell patterning. Further, the time laps observations was carried out to evaluate the axonal extension rate. The axon extended in the channel and reached to the target cell body. We found that the shorter the PC12 cell distance, the less the axonal connection time in both tetragonal and hexagonal structures. After 48 hours culture, a maximum success rate of network formation was 85% in the case of 40 μm distance tetragonal structure.

  13. In silico functional elucidation of uncharacterized proteins of Chlamydia abortus strain LLG.

    Science.gov (United States)

    Singh, Gagandeep; Sharma, Dixit; Singh, Vikram; Rani, Jyoti; Marotta, Francessco; Kumar, Manoj; Mal, Gorakh; Singh, Birbal

    2017-03-01

    This study reports structural modeling, molecular dynamics profiling of hypothetical proteins in Chlamydia abortus genome database. The hypothetical protein sequences were extracted from C. abortus LLG Genome Database for functional elucidation using in silico methods. Fifty-one proteins with their roles in defense, binding and transporting other biomolecules were unraveled. Forty-five proteins were found to be nonhomologous to proteins present in hosts infected by C. abortus . Of these, 31 proteins were related to virulence. The structural modeling of two proteins, first, WP_006344020.1 (phosphorylase) and second, WP_006344325.1 (chlamydial protease/proteasome-like activity factor) were accomplished. The conserved active sites necessary for the catalytic function were analyzed. The finally concluded proteins are envisioned as possible targets for developing drugs to curtail chlamydial infections, however, and should be validated by molecular biological methods.

  14. Structure elucidation of 3-[1-(6-methoxy-2-naphtyl)ethyl]-6-(2,4-dichlorophenyl)-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine, C23H18Cl2N4OS from synchrotron X-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gündoğdu, Gülsüm; Aytaç, Sevim Peri; Müller, Melanie; Tozkoparan, Birsen; Kaynak, Filiz Betül

    2017-12-01

    The 3-[1-(6-methoxy-2-naphtyl)ethyl]-6-(2,4-dichlorophenyl)-7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine, C23H18Cl2N4OS compound was synthesized, as a member of the family of novel potential anticancer agents. The structure of the title compound was characterized by IR,1H-NMR, mass spectroscopy, and elemental analysis, previously. In this study, the crystal structure of this compound has been determined from synchrotron X-ray powder diffraction data. The crystal structure was solved by simulated annealing and the final structure was achieved by Rietveld refinement method using soft restrains on all interatomic bond lengths and angles. This compound crystallizes in space groupP21,Z= 2, with the unit-cell parametersa= 15.55645(11) Å,b= 8.61693(6) Å,c= 8.56702(6) Å,β= 104.3270(4)°, andV= 1112.68(1) Å3. In the crystal structure, strong C-H∙∙∙πand weak intermolecular hydrogen-bonding interactions link the molecules into a three-dimensional network. The molecules are in a head-to-head arrangement in the unit cell.

  15. [Biological rhythms of thyrotropin secretion].

    Science.gov (United States)

    Hugues, J N; Reinberg, A; Lagoguey, M; Modigliani, E; Sebaoun, J

    1983-01-01

    The rhythmic pattern of TSH secretion is now well-established and is characterized by a circadian (24 h) periodicity with a pre-sleep acrophase which is modulated by endogenous oscillators and environmental synchronisers. Among external synchronisers, the sleep-waking cycle has been extensively studied and sleep onset appears to have a negative influence on the nycthemeral TSH peak. Nutritional status may affect the TSH rhythmicity since a short term starvation induces a shift in the acrophase time. Major neurotransmitter involved in the TSH rhythms are serotonine which could be responsible for the TSH nadir. By contrast dopamine is not directly implicated in the circadian pattern of TSH secretion. TRH, the main neuropeptide controlling the thyrotrope cell, certainly has a major role in the mediation of the TSH rhythmicity. The involvement of somatostatine is less clear but as assumed for dopamine, its negative influence on TSH secretion would be stronger at the time of TSH peak than at the time of nadir. The major inhibitory effect of thyroid hormones on TSH secretion and release is evident on mean serum TSH levels but does not seem responsible for serum circadian variations. Likewise, the TSH rhythm is present in both sex and influence of estrogens and androgens would only be to modulate the mean serum TSH level. Finally the physiological influence of glucocorticoids on TSH secretion has not been clearly demonstrated.

  16. Elucidation of cladofulvin biosynthesis reveals a cytochrome P450 monooxygenase required for anthraquinone dimerization.

    Science.gov (United States)

    Griffiths, Scott; Mesarich, Carl H; Saccomanno, Benedetta; Vaisberg, Abraham; De Wit, Pierre J G M; Cox, Russell; Collemare, Jérôme

    2016-06-21

    Anthraquinones are a large family of secondary metabolites (SMs) that are extensively studied for their diverse biological activities. These activities are determined by functional group decorations and the formation of dimers from anthraquinone monomers. Despite their numerous medicinal qualities, very few anthraquinone biosynthetic pathways have been elucidated so far, including the enzymatic dimerization steps. In this study, we report the elucidation of the biosynthesis of cladofulvin, an asymmetrical homodimer of nataloe-emodin produced by the fungus Cladosporium fulvum A gene cluster of 10 genes controls cladofulvin biosynthesis, which begins with the production of atrochrysone carboxylic acid by the polyketide synthase ClaG and the β-lactamase ClaF. This compound is decarboxylated by ClaH to yield emodin, which is then converted to chrysophanol hydroquinone by the reductase ClaC and the dehydratase ClaB. We show that the predicted cytochrome P450 ClaM catalyzes the dimerization of nataloe-emodin to cladofulvin. Remarkably, such dimerization dramatically increases nataloe-emodin cytotoxicity against mammalian cell lines. These findings shed light on the enzymatic mechanisms involved in anthraquinone dimerization. Future characterization of the ClaM enzyme should facilitate engineering the biosynthesis of novel, potent, dimeric anthraquinones and structurally related compound families.

  17. Elucidating pharmacodynamic interaction of silver nanoparticle - topical deliverable antibiotics

    Science.gov (United States)

    Thirumurugan, G.; Seshagiri Rao, J. V. L. N.; Dhanaraju, M. D.

    2016-07-01

    In order to exploit the potential benefits of antimicrobial combination therapy, we need a better understanding of the circumstances under which pharmacodynamic interactions expected. In this study, Pharmacodynamic interactions between silver nanoparticle (SNP) and topical antibiotics such as Cefazolin (CEF), Mupirocin (MUP), Gentamycin (GEN), Neomycin (NEO), Tetracycline (TET), Vancomycin (VAN) were investigated using the MIC test, Combination assay followed by Fractional Inhibitory concentration Index and Agar well diffusion method. SNP + MUP, SNP + NEO, SNP + VAN combinations showed Synergism (SN) and SNP + CEF, SNP + GEN, SNP + TET showed Partial synergism (PS) against Staphylococcus aureus. Four combinations (SNP + CEF, SNP + MUP, SNP + GEN, SNP + VAN) showed SN, SNP + TET showed PS and Indifferent effect (ID) were observed for SNP + NEO against Pseudomonas aeruginosa. SN was observed for SNP + CEF, SNP + GEN, SNP + NEO, SNP + TET and SNP + MUP showed ID, SNP + VAN showed PS against Escherichia coli. In addition, we elucidated the possible mechanism involved in the pharmacodynamic interaction between SNP-topical antibiotics by increased ROS level, membrane damage following protein release, K+ leakage and biofilm inhibition. Thus, our findings support that conjugation of the SNP with topical antibiotics have great potential in the topical formulation when treating complex resistant bacterial infections and where there is a need of more concentration to kill pathogenic bacteria.

  18. Elucidation of polymer induced DNA condensation. Visualisation at the single molecular level

    International Nuclear Information System (INIS)

    Martin, Alison Laura

    2002-01-01

    DNA condensation is a phenomenon that has stimulated interest from biologists, physicists, and polymer chemists for decades. At the cellular level, this process is key to the packing of DNA within the nuclear envelope, and the exposure of the appropriate nucleic acid sequences in order for transcription to occur, and proteins to be produced. The advent of gene therapy has led to an invigoration of this subject area. In order to successfully deliver to, and transfect target cells, many delivery vectors condense the therapeutic DNA into small compact particles. The nature of these particles have a considerable influence on the ultimate expression of the administered nucleic acid material. In addition, at its most fundamental, DNA itself is a classical polyelectrolyte polymer, the behaviour of which has applicability to other charged polymeric systems. There are two core interwound themes to this investigation; the visualisation of DNA condensate morphology at ultra-resolution, and the elucidation of the mechanisms of formation of these structures. The technique of atomic force microscopy is central to these investigations. Methodologies have been devised allowing the visualisation of the tertiary structure and conformational behaviour of individual DNA condensates in near in situ conditions. Condensation of the nucleic acid material has been induced by two classes of cation; small molecular cations, like those found within eukaryotic cells, and a range of cationic polymers. The cationic polymers investigated all have considerable potential as gene delivery vectors. The resultant DNA condensates have been assessed and contrasted in terms of their tertiary morphology, lateral dimensions, and structural volume. Assessments have also been made regarding the influence of the molecular architecture of the cationic moiety and the nature of the input nucleic acid material on the resultant DNA condensates. With regard to the elucidation of the mechanisms of DNA condensate

  19. Designing, structural elucidation, comparison of DNA binding, cleavage, radical scavenging activity and anticancer activity of copper(I) complex with 5-dimethyl-2-phenyl-4-[(pyridin-2-ylmethylene)-amino]-1,2-dihydro-pyrazol-3-one Schiff base ligand.

    Science.gov (United States)

    Sathiyaraj, Subbaiyan; Sampath, Krishnan; Butcher, Ray J; Pallepogu, Raghavaiah; Jayabalakrishnan, Chinnasamy

    2013-06-01

    A novel copper(I) Schiff base complex has been synthesized and fully characterized by spectral, analytical and structural modes. Single crystal X-ray diffraction studies revealed that the copper(I) complex [CuCl(PPh3)L] has a distorted tetrahedral geometry around the central copper(I) ion. The interaction of the ligand and the complex with CT-DNA has been explored by absorption titration method which revealed that the compounds could interact with CT-DNA through intercalation. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 DNA. The antioxidative properties showed that the copper(I) complex has a strong radical-scavenging potency than ligands. Further the cytotoxic effect of the compounds examined on cancerous cell lines showed that the complex exhibited substantial anticancer activity. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  20. Lanthanide-cyclodextrin complexes as probes for elucidating optical purity by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, T.J.; Bogyo, M.S.; Lebeau, E.L. (Bates College, Lewiston, ME (United States))

    1994-06-01

    A multidentate ligand is bonded to cyclodextrins by the reaction of diethylenetriaminepentaacetic dianhydride with 6-mono- and 2-mono(ethylenediamine) derivatives of cyclodextrin. Adding Dy(III) to the cyclodextrin derivatives enhances the enantiomeric resolution in the [sup 1]H NMR spectra of carbionoxamine maleate, doxylamine succinate, pheniramine maleate, propranolol hydrochloride, and tryptophan. The enhancement is more pronounced with the secondary derivative. The Dy(III)-induced shifts can be used to elucidate the geometry of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shifts are reported for complexes of aspartame, tryptophan, propranolol, and 1-anilino-8-naphthalenesulfonate with cyclodextrins, and the relative magnitudes of the shifts agree with previously reported structures of the complexes. 37 refs., 9 figs., 5 tabs.

  1. Elucidating the mechanisms of protein antigen adsorption to the CAF/NAF liposomal vaccine adjuvant systems

    DEFF Research Database (Denmark)

    Hamborg, Mette; Rose, Fabrice; Jorgensen, Lene

    2014-01-01

    is generally known about how antigens and adjuvants interact at the molecular level. The aim of this study was to elucidate the mechanisms of interactions between the equally sized, but oppositely charged model protein antigens α-lactalbumin and lysozyme, and i) the clinically tested cationic liposomal......The reverse vaccinology approach has recently resulted in the identification of promising protein antigens, which in combination with appropriate adjuvants can stimulate customized, protective immune responses. Although antigen adsorption to adjuvants influences vaccine efficacy and safety, little...... interaction with the zwitterionic liposomes. In contrast, the net cationic lysozyme showed very little interaction with either types of liposome. Adsorption of α-lactalbumin altered its tertiary structure, affected lipid membrane packing below and above the phase transition temperature, and neutralized...

  2. Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling

    Science.gov (United States)

    Grace, Joseph M.; Verseux, Cyprien; Gentry, Diana; Moffet, Amy; Thayabaran, Ramanen; Wong, Nathan; Rothschild, Lynn

    2013-01-01

    The adaptation of micro-organisms to their environments is a complex process of interaction between the pressures of the environment and of competition. Reducing this multifactorial process to environmental exposure in the laboratory is a common tool for elucidating individual mechanisms of evolution, such as mutation rates. Although such studies inform fundamental questions about the way adaptation and even speciation occur, they are often limited by labor-intensive manual techniques. Current methods for controlled study of microbial adaptation limit the length of time, the depth of collected data, and the breadth of applied environmental conditions. Small idiosyncrasies in manual techniques can have large effects on outcomes; for example, there are significant variations in induced radiation resistances following similar repeated exposure protocols. We describe here a project under development to allow rapid cycling of multiple types of microbial environmental exposure. The system allows continuous autonomous monitoring and data collection of both single species and sampled communities, independently and concurrently providing multiple types of controlled environmental pressure (temperature, radiation, chemical presence or absence, and so on) to a microbial community in dynamic response to the ecosystem's current status. When combined with DNA sequencing and extraction, such a controlled environment can cast light on microbial functional development, population dynamics, inter- and intra-species competition, and microbe-environment interaction. The project's goal is to allow rapid, repeatable iteration of studies of both natural and artificial microbial adaptation. As an example, the same system can be used both to increase the pH of a wet soil aliquot over time while periodically sampling it for genetic activity analysis, or to repeatedly expose a culture of bacteria to the presence of a toxic metal, automatically adjusting the level of toxicity based on the

  3. Property elucidation of vacuum-evaporated zinc telluride thin film ...

    Indian Academy of Sciences (India)

    The deposited film has been characterised by X-ray diffraction (XRD), atomic forcemicroscopy (AFM), and UV-VIS-NIR spectrophotometer. The polycrystalline and cubic structure of the sample has been confirmed by XRD. The order parameter(s), which determines the crystallinity and good environmental stability of the ...

  4. Linear computational QSPR for property elucidation and new ...

    African Journals Online (AJOL)

    QSPR constitutes one of the major areas within computational chemistry and refers to the process of correlating chemical structure of compounds with their physicochemical properties. To achieve this, it employs a wide range of computational programmes and computer softwares including DRAGON, MATLAB, ...

  5. Commentary: Elucidating the Neural Correlates of Early Childhood Memory

    Science.gov (United States)

    Mullally, Sinead L.

    2015-01-01

    Both episodic memory and the key neural structure believed to support it, namely the hippocampus, are believed to undergo protracted periods of postnatal developmental. Critically however, the hippocampus is comprised of distinct subfields and circuits, and these circuits appear to mature at different rates (Lavenex and Banta Lavenex, 2013).…

  6. Bottom-up elucidation of glycosidic bond stereochemistry

    DEFF Research Database (Denmark)

    Gray, Christopher J.; Schindler, Baptiste; Migas, Lukasz G.

    2017-01-01

    The lack of robust, high-throughput, and sensitive analytical strategies that can conclusively map the structure of glycans has significantly hampered progress in fundamental and applied aspects of glycoscience. Resolution of the anomeric α/β glycan linkage within oligosaccharides remains...

  7. Elucidating the Composition and Distribution of Trace Metals in Corals

    Science.gov (United States)

    Farfan, G.; Webb, S. M.; Apprill, A.; Hansel, C. M.

    2014-12-01

    Coral reefs host a plethora of marine life and thereby provide a wealth of aesthetic and economic benefits to coastal countries. Anthropogenic influences, including local coastal water contamination, however threaten the health of these delicate ecosystems. Metal incorporation into carbonate minerals, the backbone of coral reefs, is known to have a large yet variable impact on carbonate structure and solubility. Yet, trace metal influences on the structure, porosity, composition, and solubility of coral skeletons is largely unknown. Here, we coupled synchrotron-based micro-X-ray fluorescence (u-XRF) mapping and X-ray absorption near edge structure (XANES) spectroscopy with micro-X-ray diffraction (XRD) to explore the distribution and speciation of trace metals associated with corals and their impact on the carbonate structure of corals obtained from reefs varying in anthropogenic influence - Florida Keys, FL USA and the Federated States of Micronesia. Iron and copper were the most abundant metals in the biological tissue, while in some areas zinc was observed in the tissue, overlapping with the skeleton. Trace metals were not detectable in the aragonite skeletons; in fact, the distributions of Ca and Fe were anti-correlated. XANES spectra show that the iron is primarily Fe(III), likely as the poorly crystalline iron oxide ferrihydrite structure or trapped within ferretin proteins. The same trace metals were observed in corals of different species and from different environments. This in situ investigation corroborates previous studies that corals tend to incorporate iron into the biological components but not into the aragonite skeleton. Given the dominant partitioning of metals within the biological tissue rather than the coral skeleton, the specific carbon molecules responsible for metal attenuation and their fate under changing geochemical conditions and following coral death require exploration.

  8. Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling

    Science.gov (United States)

    Grace, J. M.; Verseux, C.; Gentry, D.; Moffet, A.; Thayabaran, R.; Wong, N.; Rothschild, L.

    2013-12-01

    The adaptation of micro-organisms to their environments is a complex process of interaction between the pressures of the environment and of competition. Reducing this multifactorial process to environmental exposure in the laboratory is a common tool for elucidating individual mechanisms of evolution, such as mutation rates[Wielgoss et al., 2013]. Although such studies inform fundamental questions about the way adaptation and even speciation occur, they are often limited by labor-intensive manual techniques[Wassmann et al., 2010]. Current methods for controlled study of microbial adaptation limit the length of time, the depth of collected data, and the breadth of applied environmental conditions. Small idiosyncrasies in manual techniques can have large effects on outcomes; for example, there are significant variations in induced radiation resistances following similar repeated exposure protocols[Alcántara-Díaz et al., 2004; Goldman and Travisano, 2011]. We describe here a project under development to allow rapid cycling of multiple types of microbial environmental exposure. The system allows continuous autonomous monitoring and data collection of both single species and sampled communities, independently and concurrently providing multiple types of controlled environmental pressure (temperature, radiation, chemical presence or absence, and so on) to a microbial community in dynamic response to the ecosystem's current status. When combined with DNA sequencing and extraction, such a controlled environment can cast light on microbial functional development, population dynamics, inter- and intra-species competition, and microbe-environment interaction. The project's goal is to allow rapid, repeatable iteration of studies of both natural and artificial microbial adaptation. As an example, the same system can be used both to increase the pH of a wet soil aliquot over time while periodically sampling it for genetic activity analysis, or to repeatedly expose a culture of

  9. Structural and Functional Elucidation of Yeast Lanosterol 14?-Demethylase in Complex with Agrochemical Antifungals

    OpenAIRE

    Tyndall, Joel D. A.; Sabherwal, Manya; Sagatova, Alia A.; Keniya, Mikhail V.; Negroni, Jacopo; Wilson, Rajni K.; Woods, Matthew A.; Tietjen, Klaus; Monk, Brian C.

    2016-01-01

    Azole antifungals, known as demethylase inhibitors (DMIs), target sterol 14α-demethylase (CYP51) in the ergosterol biosynthetic pathway of fungal pathogens of both plants and humans. DMIs remain the treatment of choice in crop protection against a wide range of fungal phytopathogens that have the potential to reduce crop yields and threaten food security. We used a yeast membrane protein expression system to overexpress recombinant hexahistidine-tagged S. cerevisiae lanosterol 14α-demethylase...

  10. Isolation and Structure Elucidation of Radical Scavengers from Thymus vulgaris Leaves

    NARCIS (Netherlands)

    Dapkevicius, A.; Beek, van T.A.; Lelyveld, G.P.; Veldhuizen, van A.; Groot, de Æ.; Linssen, J.P.H.; Venskutonis, R.

    2002-01-01

    2,2-Diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging activity-guided fractionation of a leaf extract of Thymus vulgaris led to the isolation of the radical scavengers rosmarinic acid 1, eriodictyol, taxifolin, luteolin 7-glucuronide, p-cymene 2,3-diol, p-cymene 2,3-diol 6-6'-dimer, carvacrol,

  11. Isolation and structure elucidation of pectic polysaccharide from rose hip fruits (Rosa canina L.)

    NARCIS (Netherlands)

    Ognyanov, Manol; Remoroza, Connie; Schols, Henk A.; Georgiev, Yordan; Kratchanova, Maria; Kratchanov, Christo

    2016-01-01

    A pectic polysaccharide from rose hip (RH) fruits has been obtained by extraction with 1% aqueous citric acid. It was found that the polysaccharide fraction mainly consisted of galacturonic acid (45.5%) next to galactose (5.5%) and arabinose (4.7%). RH pectin is having a relatively high degree of

  12. Isolationand structure elucidation of coumarin and cinamate derivatives from Lycium ruthenicum

    Directory of Open Access Journals (Sweden)

    Hassan Valizadeh

    2014-10-01

    Full Text Available Lyciumspecies is a popular medicinal plant in the traditional Chinese medicine and Lycium ru-thenicum is a native medicinal plant of Iran. Lycium genus has several biologically important properties too. Investigation of chemical composition of ethyl acetate extract of this plant is the goal of this study. Two coumarins (Scopoletin and Sculetin and Methyl-2-hydroxy-4-undecanoxy-trans-cinamate were isolated and characterized as the major constituents using 1H NMR, 13C NMR and FT-IR spectroscopic data, MS spectrometry, elemental analysis and by comparison with the literature values. Phytochemical investigation of Lyciumruthenicum demonstrated the presence of important biologically active compounds. This is the first phyto-chemical study of this species in Iran.

  13. Nature's Sedative: Isolation and Structural Elucidation of Valtrate from Centranthus Ruber

    Science.gov (United States)

    Doyle, Andrea M.; Reilly, Joe; Murphy, Niamh; Kavanagh, Pierce V.; O'Brien, John E.; Walsh, Martin S.; Walsh, John J.

    2004-01-01

    A member of a related genus of the valerianaceae, Centranthus ruber, is used, that yields a higher percentage valtrate than other related species such as "Valeriana officinalis," there by making easier isolation in pure form.

  14. Cannabis—XV . Pyrolysis of cannabidiol. Structure elucidation of four pyrolytic products

    NARCIS (Netherlands)

    Kuppers, F.J.E.M.; Bercht, C.A.L.; Salemink, C.A.; Lousberg, R.J.J.Ch.

    1975-01-01

    Pyrolysis of cannabidiol in nitrogen atmosphere affords at least six more products with longer GC-retention times than CBD, next to unconverted CBD. Two of these could be identified as Δ1(2)THC and CBN Two further products were investigated and their mass spectrometrical fragmentations and

  15. PMA-PhyloChip DNA Microarray to Elucidate Viable Microbial Community Structure

    Science.gov (United States)

    Venkateswaran, Kasthuri J.; Stam, Christina N.; Andersen, Gary L.; DeSantis, Todd

    2011-01-01

    Since the Viking missions in the mid-1970s, traditional culture-based methods have been used for microbial enumeration by various NASA programs. Viable microbes are of particular concern for spacecraft cleanliness, for forward contamination of extraterrestrial bodies (proliferation of microbes), and for crew health/safety (viable pathogenic microbes). However, a "true" estimation of viable microbial population and differentiation from their dead cells using the most sensitive molecular methods is a challenge, because of the stability of DNA from dead cells. The goal of this research is to evaluate a rapid and sensitive microbial detection concept that will selectively estimate viable microbes. Nucleic acid amplification approaches such as the polymerase chain reaction (PCR) have shown promise for reducing time to detection for a wide range of applications. The proposed method is based on the use of a fluorescent DNA intercalating agent, propidium monoazide (PMA), which can only penetrate the membrane of dead cells. The PMA-quenched reaction mixtures can be screened, where only the DNA from live cells will be available for subsequent PCR reaction and microarray detection, and be identified as part of the viable microbial community. An additional advantage of the proposed rapid method is that it will detect viable microbes and differentiate from dead cells in only a few hours, as opposed to less comprehensive culture-based assays, which take days to complete. This novel combination approach is called the PMA-Microarray method. DNA intercalating agents such as PMA have previously been used to selectively distinguish between viable and dead bacterial cells. Once in the cell, the dye intercalates with the DNA and, upon photolysis under visible light, produces stable DNA adducts. DNA cross-linked in this way is unavailable for PCR. Environmental samples suspected of containing a mixture of live and dead microbial cells/spores will be treated with PMA, and then incubated in the dark. Thereafter, the sample is exposed to visible light for five minutes, so that the DNA from dead cells will be cross-linked. Following this PMA treatment step, the sample is concentrated by centrifugation and washed (to remove excessive PMA) before DNA is extracted. The 16S rRNA gene fragments will be amplified by PCR to screen the total microbial community using PhyloChip DNA microarray analysis. This approach will detect only the viable microbial community since the PMA intercalated DNA from dead cells would be unavailable for PCR amplification. The total detection time including PCR reaction for low biomass samples will be a few hours. Numerous markets may use this technology. The food industry uses spore detection to validate new alternative food processing technologies, sterility, and quality. Pharmaceutical and medical equipment companies also detect spores as a marker for sterility. This system can be used for validating sterilization processes, water treatment systems, and in various public health and homeland security applications.

  16. Study on a new antifungal antibiotic, yimeimycin--isolation, structure elucidation and biological activities

    International Nuclear Information System (INIS)

    Shi Yuefeng; Sang Jinlong; Zhu Lihong; Li Xiaohui; Wu Jian

    2004-01-01

    Strain HA-8416, the producer of yimeimycin, was isolated from a soil sample collected in Hangzhou, Zhejiang province, China. Based on the investigation of morphological, cultural, physiological and biochemical characteristic as well as the cell wall chemical composition, strain HA8416 is extremely similar to Streptomyces hygrospinosus SF-104, and named Streptomyces hygrospinosus var tianmushanensis n. var. Sand et al. By means of spectroscopic analysis (UV, 1 H-NMR, DEPT CNMR and H-H COSY), yimeimycin was identified as a new antibiotic of the nucleoside family. Yimeimeycin appeared no activities against G + /G-bacteria, but was active against the fungi, Sphaerotheca cucurbitae, Pellicularia sasakii, Colletotrichum orbiculare, especially

  17. Structural elucidation of main ozonation products of the artificial sweeteners cyclamate and acesulfame.

    Science.gov (United States)

    Scheurer, Marco; Godejohann, Markus; Wick, Arne; Happel, Oliver; Ternes, Thomas A; Brauch, Heinz-Jürgen; Ruck, Wolfgang K L; Lange, Frank Thomas

    2012-05-01

    The two artificial sweeteners cyclamate (CYC) and acesulfame (ACE) have been detected in wastewater and drinking water treatment plants. As in both facilities ozonation might be applied, it is important to find out if undesired oxidation products (OPs) are formed. For the separation and detection of the OPs, several analytical techniques, including nuclear magnetic resonance experiments, were applied. In order to distinguish between direct ozone reaction and a radical mechanism, experiments were carried out at different pH values with and without scavenging OH radicals. Kinetic experiments were used for confirmation that the OPs are formed during short ozone contact time applied in waterworks. Samples from a waterworks using bank filtrate as raw water were analyzed in order to prove that the identified OPs are formed in real and full-scale ozone applications. In the case of CYC, oxidation mainly occurs at the carbon atom, where the sulfonamide moiety is bound to the cyclohexyl ring. Consequently, amidosulfonic acid and cyclohexanone are formed as main OPs of CYC. When ozone reacts at another carbon atom of the ring a keto moiety is introduced into the CYC molecule. Acetic acid and the product ACE OP170, an anionic compound with m/z=170 and an aldehyde hydrate moiety, were identified as the main OPs for ACE. The observed reaction products suggest an ozone reaction according to the Criegee mechanism due to the presence of a C=C double bond. ACE OP170 was also detected after the ozonation unit of a full-scale drinking water treatment plant which uses surface water-influenced bank filtrate as raw water. Acesulfame can be expected to be found in anthropogenic-influenced raw water used for drinking water production. However, when ACE OP170 is formed during ozonation, it is not expected to cause any problem for drinking water suppliers, because the primary findings suggest its removal in subsequent treatment steps, such as activated carbon filters.

  18. Elucidating the Link between NMR Chemical Shifts and Electronic Structure in d(0) Olefin Metathesis Catalysts.

    Science.gov (United States)

    Halbert, Stéphanie; Copéret, Christophe; Raynaud, Christophe; Eisenstein, Odile

    2016-02-24

    The nucleophilic carbon of d(0) Schrock alkylidene metathesis catalysts, [M] = CHR, display surprisingly low downfield chemical shift (δ(iso)) and large chemical shift anisotropy. State-of-the-art four-component relativistic calculations of the chemical shift tensors combined with a two-component analysis in terms of localized orbitals allow a molecular-level understanding of their orientations, the magnitude of their principal components (δ11 > δ22 > δ33) and associated δ(iso). This analysis reveals the dominating influence of the paramagnetic contribution yielding a highly deshielded alkylidene carbon. The largest paramagnetic contribution, which originates from the coupling of alkylidene σ(MC) and π*(MC) orbitals under the action of the magnetic field, is analogous to that resulting from coupling σ(CC) and π*(CC) in ethylene; thus, δ11 is in the MCH plane and is perpendicular to the MC internuclear direction. The higher value of carbon-13 δ(iso) in alkylidene complexes relative to ethylene is thus due to the smaller energy gap between σ(MC) and π*(MC) vs this between σ(CC) and π*(CC) in ethylene. This effect also explains why the highest value of δ(iso) is observed for Mo and the lowest for Ta, the values for W and Re being in between. In the presence of agostic interaction, the chemical shift tensor principal components orientation (δ22 or δ33 parallel or perpendicular to π(MX)) is influenced by the MCH angle because it determines the orientation of the alkylidene CHR fragment relative to the MC internuclear axis. The orbital analysis shows how the paramagnetic terms, understood with a localized bond model, determine the chemical shift tensor and thereby δ(iso).

  19. Isolation and Structural Elucidation of Antiproliferative Compounds of Lipidic Fractions from White Shrimp Muscle (Litopenaeus vannamei)

    Science.gov (United States)

    López-Saiz, Carmen-María; Velázquez, Carlos; Hernández, Javier; Cinco-Moroyoqui, Francisco-Javier; Plascencia-Jatomea, Maribel; Robles-Sánchez, Maribel; Machi-Lara, Lorena; Burgos-Hernández, Armando

    2014-01-01

    Shrimp is one of the most popular seafood items worldwide, and has been reported as a source of chemopreventive compounds. In this study, shrimp lipids were separated by solvent partition and further fractionated by semi-preparative RP-HPLC and finally by open column chromatography in order to obtain isolated antiproliferative compounds. Antiproliferative activity was assessed by inhibition of M12.C3.F6 murine cell growth using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay. The methanolic fraction showed the highest antiproliferative activity; this fraction was separated into 15 different sub-fractions (M1–M15). Fractions M8, M9, M10, M12, and M13 were antiproliferative at 100 µg/mL and they were further tested at lower concentrations. Fractions M12 and M13 exerted the highest growth inhibition with an IC50 of 19.5 ± 8.6 and 34.9 ± 7.3 µg/mL, respectively. Fraction M12 was further fractionated in three sub-fractions M12a, M12b, and M12c. Fraction M12a was identified as di-ethyl-hexyl-phthalate, fraction M12b as a triglyceride substituted by at least two fatty acids (predominantly oleic acid accompanied with eicosapentaenoic acid) and fraction M12c as another triglyceride substituted with eicosapentaenoic acid and saturated fatty acids. Bioactive triglyceride contained in M12c exerted the highest antiproliferative activity with an IC50 of 11.33 ± 5.6 µg/mL. Biological activity in shrimp had been previously attributed to astaxanthin; this study demonstrated that polyunsaturated fatty acids are the main compounds responsible for antiproliferative activity. PMID:25526568

  20. Structure elucidation and stereoselective total synthesis of pavettamine, the causal agent of gousiekte

    CSIR Research Space (South Africa)

    Bode, ML

    2010-03-01

    Full Text Available data of the acetonide derivative. The absolute stereochemistry was established by total synthesis from (2S)-malic acid using chiral sulfoxide methodology as (2S,4R,8R,10S)-1,11-diamino-6-aza-undecane-2,4,8,10-tetraol....

  1. Synthesis and structural elucidation of glutathione and N-aceyl-cysteine conjugates of 5-aminosalicylic acid

    DEFF Research Database (Denmark)

    Jensen, J.; Cornett, Claus; Olsen, C. E.

    1993-01-01

    conjugates of 5-ASA and GSH were found to be formed. 5-ASA was initially oxidized by PbO2 in a solution of TRIS-HCl buffer pH 9.3 followed by the in situ addition of N-acetyl-cysteine or glutathione to the oxidized 5-ASA at pH 7.5. The resulting conjugates were N-acetylated at the aromatic amino group......The ability of 5-aminosalicylic acid (5-ASA) to be oxidized to a quinone monoimine compound capable of conjugating with nucleophilic compounds such as N-acetyl-cysteine (NAC) and glutathione (GSH) has been investigated in vitro. Three isomeric conjugates of 5-ASA and NAC as well as three isomeric...... dose of 5-ASA into mercapturic acids of 5-ASA, when 1 g of 5-ASA was ingested. In spite of the low detection limits, none of the mercapturic acid conjugates was detected in the urine from persons treated with 5-ASA....

  2. Proton NMR studies on Megaphaera elsdenii flavodoxin : structure elucidation by 2D-NMR and implications

    NARCIS (Netherlands)

    Mierlo, van C.

    1990-01-01

    1H NMR techniques have been applied for a thorough study of the uncrystallizable Megasphaera elsdenii flavodoxin in its three redox states. The aim of the research project described in this thesis was to obtain answers regarding questions

  3. Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

    NARCIS (Netherlands)

    Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2012-01-01

    The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

  4. Structure-function elucidation of a new alpha-Conotoxin, Lo1a, from Conus longurionis.

    Digital Repository Service at National Institute of Oceanography (India)

    Lebbe, E.K.M.; Peigneur, S.; Maiti, M.; PrabhaDevi; Ravichandran, S.; Lescrinier, E.; Ulens, C.; Waelkens, E.; DeSouza, L.; Herdewijn, P.; Tytgat, J.

    C-terminal Asp deletion, whereas in Lo1a-RRR, a triple-Arg tail replaces the Asp. They blocked the neuronal nAChR Alpha 7 with a lower IC50 value, but remarkably, both adopted affinity for the muscle subtype Alpha1 Beta1 delta ~e....

  5. The Crystal Structure of the Malaria Pigment Hemozoin as Elucidated by X-ray Powder Diffraction

    DEFF Research Database (Denmark)

    Straasø, Tine

    in the eradication of malaria. This thesis is a step towards that goal. When examining red blood cells from an infected person under a microscope dark pigment is observed. This dark pigment is actually small crystals called hemozoin. Hemozoin is a by-product formed by the parasite and a necessity for parasitic...

  6. Structural elucidation of lignin polymers of Eucalyptus chips during organosolv pretreatment and extended delignification.

    Science.gov (United States)

    Wen, Jia-Long; Sun, Shao-Long; Yuan, Tong-Qi; Xu, Feng; Sun, Run-Cang

    2013-11-20

    Effective delignification of lignocelluloses is a very important to guarantee the economic feasibility of organosolv-based biorefinery. Eucalyptus chips were successively subjected to organosolv pretreatment (AEOP) and extended delignification (ED) process in the present study. The effects of delignification processes were scientifically evaluated by component analysis, SEM, and CP-MAS NMR techniques. It was found that the integrated process of organosolv pretreatment and subsequent delignification resulted in an effective delignification. The fundamental chemistry of the lignin obtained after these processes was thoroughly investigated by FT-IR, multidimensional NMR ((31)P-, (13)C-, and 2D-HSQC NMR), and GPC techniques. It was observed that an extensive cleavage of aryl ether linkages, ethoxylation, and some condensation reactions occurred in AEOP process, while α-oxidation mainly took place in alkaline hydrogen peroxide (AHP) process. It is believed that better understanding the fundamental chemistry of lignin facilitates the optimization of the delignification process. More importantly, well-defined of lignin polymers will facilitate their value-added applications in current and future biorefineries.

  7. Structure elucidation of some insect pheromones : a contribution to the development of selective pest control agents

    NARCIS (Netherlands)

    Persoons, C.J.

    1977-01-01

    The use of pheromones is one of the methods currently being investigated intensively as an alternative method of insect control. The various ways in which pheromones might be used in insect control programmes are briefly discussed in Chapter 1.

    Chapter 2 gives a detailed description of the

  8. Structure elucidation and degradation kinetic study of Ofloxacin using surface enhanced Raman spectroscopy

    Science.gov (United States)

    El-Zahry, Marwa R.; Lendl, Bernhard

    2018-03-01

    A simple, fast and sensitive surface enhanced Raman spectroscopy (SERS) method for quantitative determination of fluoroquinolone antibiotic Ofloxacin (OFX) is presented. Also the stability behavior of OFX was investigated by monitoring the SERS spectra of OFX after various degradation processes. Acidic, basic and oxidative force degradation processes were applied at different time intervals. The forced degradation conditions were conducted and followed using SERS method utilizing silver nanoparticles (Ag NPs) as a SERS substrate. The Ag NPs colloids were prepared by reduction of silver nitrate using polyethyelene glycol (PEG) as a reducing and stabilizing agent. Validation tests were done in accordance with International Conference on Harmonization (ICH) guidelines. The calibration curve with a correlation coefficient (R = 0.9992) was constructed as a relationship between the concentration range of OFX (100-500 ng/ml) and SERS intensity at 1394 cm- 1 band. LOD and LOQ values were calculated and found to be 23.5 ng/ml and 72.6 ng/ml, respectively. The developed method was applied successfully for quantitation of OFX in different pharmaceutical dosage forms. Kinetic parameters were calculated including rate constant of the degradation of the studied antibiotic.

  9. Photohuperzine A-A new photoisomer of huperzine A: Structure elucidation, formation kinetics and activity assessment

    NARCIS (Netherlands)

    de Azevedo Marques, L.; Giera, M.; de Kanter, F.J.J.; Niessen, W.M.A.; Lingeman, H.; Irth, H.

    2010-01-01

    A new photoisomer of the promising " anti-Alzheimer" drug candidate (±) huperzine A is described. The new substance was formed via a photoisomerization reaction and was found to be 1-amino-13-ethylidene-11-methyl-6-aza-tetracyclo-[7.3.1.0

  10. Elucidating the Interacting Domains of Chandipura Virus Nucleocapsid Protein

    Directory of Open Access Journals (Sweden)

    Kapila Kumar

    2013-01-01

    Full Text Available The nucleocapsid (N protein of Chandipura virus (CHPV plays a crucial role in viral life cycle, besides being an important structural component of the virion through proper organization of its interactions with other viral proteins. In a recent study, the authors had mapped the associations among CHPV proteins and shown that N protein interacts with four of the viral proteins: N, phosphoprotein (P, matrix protein (M, and glycoprotein (G. The present study aimed to distinguish the regions of CHPV N protein responsible for its interactions with other viral proteins. In this direction, we have generated the structure of CHPV N protein by homology modeling using SWISS-MODEL workspace and Accelrys Discovery Studio client 2.55 and mapped the domains of N protein using PiSQRD. The interactions of N protein fragments with other proteins were determined by ZDOCK rigid-body docking method and validated by yeast two-hybrid and ELISA. The study revealed a unique binding site, comprising of amino acids 1–30 at the N terminus of the nucleocapsid protein (N1 that is instrumental in its interactions with N, P, M, and G proteins. It was also observed that N2 associates with N and G proteins while N3 interacts with N, P, and M proteins.

  11. Elucidating a chemical defense mechanism of Antarctic sponges: A computational study.

    Science.gov (United States)

    Vankayala, Sai Lakshmana; Kearns, Fiona L; Baker, Bill J; Larkin, Joseph D; Lee Woodcock, H

    2017-01-01

    In 2000, a novel secondary metabolite (erebusinone, Ereb) was isolated from the Antarctic sea sponge, Isodictya erinacea. The bioactivity of Ereb was investigated, and it was found to inhibit molting when fed to the arthropod species Orchomene plebs. Xanthurenic acid (XA) is a known endogenous molt regulator present in arthropods. Experimental studies have confirmed that XA inhibits molting by binding to either (or both) of two P450 enzymes (CYP315a1 or CYP314a1) that are responsible for the final two hydroxylations in the production of the molt-inducing hormone, 20-hydroxyecdysone (20E). The lack of crystal structures and biochemical assays for CYP315a1 or CYP314a1, has prevented further experimental exploration of XA and Ereb's molt inhibition mechanisms. Herein, a wide array of computational techniques - homology modeling, molecular dynamics simulations, binding site bioinformatics, flexible receptor-flexible ligand docking, and molecular mechanics-generalized Born surface area calculations - have been employed to elucidate the structure-function relationships between the aforementioned P450s and the two described small molecule inhibitors (Ereb and XA). Results indicate that Ereb likely targets CYP315a1 by interacting with a network of aromatic residues in the binding site, while XA may inhibit both CYP315a1 and CYP314a1 because of its aromatic, as well as charged nature. Copyright © 2016. Published by Elsevier Inc.

  12. SUCROSE SYNTHASE: ELUCIDATION OF COMPLEX POST-TRANSLATIONAL REGULATORY MECHANISMS

    Energy Technology Data Exchange (ETDEWEB)

    Steven C. Huber

    2009-05-12

    Studies have focused on the enzyme sucrose synthase, which plays an important role in the metabolism of sucrose in seeds and tubers. There are three isoforms of SUS in maize, referred to as SUS1, SUS-SH1, and SUS2. SUS is generally considered to be tetrameric protein but recent evidence suggests that SUS can also occur as a dimeric protein. The formation of tetrameric SUS is regulated by sucrose concentration in vitro and this could also be an important factor in the cellular localization of the protein. We found that high sucrose concentrations, which promote tetramer formation, also inhibit the binding of SUS1 to actin filaments in vitro. Previously, high sucrose concentrations were shown to promote SUS association with the plasma membrane. The specific regions of the SUS molecule involved in oligomerization are not known, but we identified a region of the SUS1 moelcule by bioinformatic analysis that was predicted to form a coiled coil. We demonstrated that this sequence could, in fact, self-associate as predicted for a coiled coil, but truncation analysis with the full-length recombinant protein suggested that it was not responsible for formation of dimers or tetramers. However, the coiled coil may function in binding of other proteins to SUS1. Overall, sugar availability may differentially influence the binding of SUS to cellular structures, and these effects may be mediated by changes in the oligomeric nature of the enzyme.

  13. Shiver me titin! Elucidating titin's role in shivering thermogenesis.

    Science.gov (United States)

    Taylor-Burt, Kari R; Monroy, Jenna; Pace, Cinnamon; Lindstedt, Stan; Nishikawa, Kiisa C

    2015-03-01

    Shivering frequency scales predictably with body mass and is 10 times higher in a mouse than a moose. The link between shivering frequency and body mass may lie in the tuning of muscle elastic properties. Titin functions as a muscle 'spring', so shivering frequency may be linked to titin's structure. The muscular dystrophy with myositis (mdm) mouse is characterized by a deletion in titin's N2A region. Mice that are homozygous for the mdm mutation have a lower body mass, stiffer gait and reduced lifespan compared with their wild-type and heterozygous siblings. We characterized thermoregulation in these mice by measuring metabolic rate and tremor frequency during shivering. Mutants were heterothermic at ambient temperatures of 20-37°C while wild-type and heterozygous mice were homeothermic. Metabolic rate increased at smaller temperature differentials (i.e. the difference between body and ambient temperatures) in mutants than in non-mutants. The difference between observed tremor frequencies and shivering frequencies predicted by body mass was significantly larger for mutant mice than for wild-type or heterozygous mice, even after accounting for differences in body temperature. Together, the heterothermy in mutants, the increase in metabolic rate at low temperature differentials and the decreased tremor frequency demonstrate the thermoregulatory challenges faced by mice with the mdm mutation. Oscillatory frequency is proportional to the square root of stiffness, and we observed that mutants had lower active muscle stiffness in vitro. The lower tremor frequencies in mutants are consistent with reduced active muscle stiffness and suggest that titin affects the tuning of shivering frequency. © 2015. Published by The Company of Biologists Ltd.

  14. Elucidating dimensions of posttraumatic stress symptoms and their functional correlates in disaster-exposed adolescents.

    Science.gov (United States)

    Sumner, Jennifer A; Pietrzak, Robert H; Danielson, Carla Kmett; Adams, Zachary W; Ruggiero, Kenneth J

    2014-12-01

    The aim of this study was to elucidate the dimensional structure of posttraumatic stress disorder (PTSD) and potential moderators and functional correlates of this structure in disaster-affected adolescents. A population-based sample of 2000 adolescents aged 12-17 years (M = 14.5 years; 51% female) completed interviews on post-tornado PTSD symptoms, substance use, and parent-adolescent conflict between 4 and 13 months (M = 8.8, SD = 2.6) after tornado exposure. Confirmatory factor analyses revealed that all models fit well but a 5-factor dysphoric arousal model provided a statistically significantly better representation of adolescent PTSD symptoms compared to 4-factor dysphoria and emotional numbing models. There was evidence of measurement invariance of the dysphoric arousal model across gender and age, although girls and older adolescents aged 15-17 years had higher mean scores than boys and younger adolescents aged 12-14 years, respectively, on some PTSD dimensions. Differential magnitudes of association between PTSD symptom dimensions and functional correlates were observed, with emotional numbing symptoms most strongly positively associated with problematic substance use since the tornado, and dysphoric arousal symptoms most strongly positively associated with parent-adolescent conflict; both correlations were significantly larger than the corresponding correlations with anxious arousal. Taken together, these results suggest that the dimensional structure of tornado-related PTSD symptomatology in adolescents is optimally characterized by five separate clusters of re-experiencing, avoidance, numbing, dysphoric arousal, and anxious arousal symptoms, which showed unique associations with functional correlates. Findings emphasize that PTSD in disaster-exposed adolescents is not best conceptualized as a homogenous construct and highlight potential differential targets for post-disaster assessment and intervention. Copyright © 2014 Elsevier Ltd. All rights

  15. Crosslinked electrospun PVA nanofibrous membranes: elucidation of their physicochemical, physicomechanical and molecular disposition

    International Nuclear Information System (INIS)

    Shaikh, Rubina P; Kumar, Pradeep; Choonara, Yahya E; Du Toit, Lisa C; Pillay, Viness

    2012-01-01

    The effects of modifying electrospun poly(vinyl alcohol) (PVA) nanofibers through crosslinking using glutaraldehyde (GA) are explored in this paper. Various concentrations of PVA solutions containing model drugs rifampicin (RIF) and isoniazid (INH) were electrospun and thereafter crosslinked using GA vapors. PVA nanofibers demonstrated high drug entrapment efficiency of 98.77% ± 1.384% and 95.07% ± 1.988% for the INH- and RIF-loaded PVA nanofibers, respectively. The surface morphology, molecular vibrational transitions, tensile attributes and in vitro drug release were characterized and supported by in silico molecular mechanics simulations. Results indicated that crosslinking caused a significant reduction in the rate of drug release where 81.11% ± 2.35% of INH and 59.31% ± 2.57% of RIF were released after 12 h. Tensile properties such as the ultimate strength and Young's modulus increased after crosslinking, caused by crosslinks forming between PVA nanofibers as was revealed through scanning electron microscopy analysis. Fourier Transform infrared analysis was conducted to further support the mode of crosslinking. Additionally, image processing analysis was carried out to quantify the effect of formulation variables on the morphology of nanofibers. Furthermore, the effect of GA-induced crosslinking and addition of drugs on the performance of electrospun fibers was further elucidated and conceptualized using a molecular mechanics assisted model building and energy refinement approach via molecular mechanics energy relationships by exploring the spatial disposition of energy-minimized molecular structures of the polymer, crosslinker and the drugs. (paper)

  16. Elucidation of the relationships between H-bonding patterns and excited state dynamics in cyclovalone.

    Science.gov (United States)

    Lamperti, Marco; Maspero, Angelo; Tønnesen, Hanne H; Bondani, Maria; Nardo, Luca

    2014-08-28

    Cyclovalone is a synthetic curcumin derivative in which the keto-enolic system is replaced by a cyclohexanone ring. This modification of the chemical structure might in principle result in an excited state that is more stable than that of curcumin, which in turn should produce an enhanced phototoxicity. Indeed, although curcumin exhibits photosensitized antibacterial activity, this compound is characterized by very fast excited-state dynamics which limit its efficacy as a photosensitizer. In previous works we showed that the main non-radiative decay pathway of keto-enolic curcuminoids is through excited-state transfer of the enolic proton to the keto-oxygen. Another effective deactivation pathway involves an intermolecular charge transfer mechanism occurring at the phenyl rings, made possible by intramolecular H-bonding between the methoxy and the hydroxyl substituent. In this paper we present UV-Vis and IR absorption spectra data with the aim of elucidating the intramolecular charge distribution of this compound and its solvation patterns in different environments, with particular focus on solute-solvent H-bonding features. Moreover, we discuss steady state and time-resolved fluorescence data that aim at characterizing the excited-state dynamics of cyclovalone, and we compare its decay photophysics to that of curcumin. Finally, because during the characterization procedures we found evidence of very fast photodegradation of cyclovalone, its photostability in four organic solvents was studied by HPLC and the corresponding relative degradation rates were calculated.

  17. Elucidation of the Relationships between H-Bonding Patterns and Excited State Dynamics in Cyclovalone

    Directory of Open Access Journals (Sweden)

    Marco Lamperti

    2014-08-01

    Full Text Available Cyclovalone is a synthetic curcumin derivative in which the keto-enolic system is replaced by a cyclohexanone ring. This modification of the chemical structure might in principle result in an excited state that is more stable than that of curcumin, which in turn should produce an enhanced phototoxicity. Indeed, although curcumin exhibits photosensitized antibacterial activity, this compound is characterized by very fast excited-state dynamics which limit its efficacy as a photosensitizer. In previous works we showed that the main non-radiative decay pathway of keto-enolic curcuminoids is through excited-state transfer of the enolic proton to the keto-oxygen. Another effective deactivation pathway involves an intermolecular charge transfer mechanism occurring at the phenyl rings, made possible by intramolecular H-bonding between the methoxy and the hydroxyl substituent. In this paper we present UV-Vis and IR absorption spectra data with the aim of elucidating the intramolecular charge distribution of this compound and its solvation patterns in different environments, with particular focus on solute-solvent H-bonding features. Moreover, we discuss steady state and time-resolved fluorescence data that aim at characterizing the excited-state dynamics of cyclovalone, and we compare its decay photophysics to that of curcumin. Finally, because during the characterization procedures we found evidence of very fast photodegradation of cyclovalone, its photostability in four organic solvents was studied by HPLC and the corresponding relative degradation rates were calculated.

  18. Elucidation of two photon absorption of ethylenediaminium (2,4-dinitrophenolate) crystals

    Science.gov (United States)

    Indumathi, C.; Sabari Girisun, T. C.; Anitha, K.; Cecil Raj, S. Alfred

    2016-10-01

    Optical quality single crystals of ethylenediaminium (2,4-dinitrophenolate) [EDA(2,4)DNP] were grown by solvent evaporation method for optical limiting applications against intense ultrashot pulse lasers. Single crystal XRD showed that the material crystallizes in monoclinic system with centric space group P21/C. The crystal packing diagram was elucidated for the first time in literature and it revealed six hydrogen bonds played a very important role in stabilizing the structure. A bifurcated hydrogen bond was also observed between ethylenediamminium and dinitrophenolate ions. The formation of charge transfer complex during the reaction of ethylenediamine and 2,4-dinitrophenol was strongly evident through the vibrational spectroscopic studies. TG-DTA and DSC curves indicate that the material exhibited strong decomposition at 224 °C. Ground state absorption analysis showed that the grown crystals possess absorption maxima in UV region (270 nm, 346 nm) and wide optical transmittance window (480-1200 nm) in the entire visible and NIR region. Measurement of two photon absorption (2PA) and optical limiting response by Z-scan technique under nanosecond pulse excitation was reported. Hence EDA(2,4)DNP with high 2PA coefficient (0.79 ± 0.04 × 10-10 m/W) and low limiting threshold (2.40 ± 0.05 × 1012 W/m2) will be a potential candidate for optical limiting applications like eye and sensor protection against short pulse lasers that are well spread in human interactive sectors.

  19. Research Trend of Physical Skill Science --Towards Elucidation of Physical Skill--

    Science.gov (United States)

    Furukawa, Koichi; Ueno, Ken; Ozaki, Tomonobu; Kamisato, Shihoko; Kawamoto, Ryuji; Shibuya, Koji; Shiratori, Naruhiko; Suwa, Masaki; Soga, Masato; Taki, Hirokazu; Fujinami, Tsutomu; Hori, Satoshi; Motomura, Yoichi; Morita, Souhei

    Physical skills and language skills are both fundamental intelligent abilities of human being. In this paper, we focus our attention to such sophisticated physical skills as playing sports and playing instruments and introduce research activities aiming at elucidating and verbalizing them. This research area has been launched recently. We introduce approaches from physical modeling, measurements and data analysis, cognitive science and human interface. We also discuss such issues as skill acquisition and its support systems. Furthermore, we consider a fundamental issue of individual differences occurring in every application of skill elucidation. Finally we introduce several attempts of skill elucidation in the fields of dancing, manufacturing, playing string instruments, sports science and medical care.

  20. Chronic exposure in vivo to thyrotropin receptor stimulating monoclonal antibodies sustains high thyroxine levels and thyroid hyperplasia in thyroid autoimmunity-prone HLA-DRB1*0301 transgenic mice.

    Science.gov (United States)

    Flynn, Jeffrey C; Gilbert, Jacqueline A; Meroueh, Chady; Snower, Daniel P; David, Chella S; Kong, Yi-chi M; Banga, J Paul

    2007-10-01

    We have examined the induction of autoimmunity and the maintenance of sustained hyperthyroidism in autoimmunity-prone human leucocyte antigen (HLA) DR3 transgenic non-obese diabetic (NOD) mice following chronic stimulation of the thyrotropin receptor (TSHR) by monoclonal thyroid-stimulating autoantibodies (TSAbs). Animals received weekly injections over the course of 9 weeks of monoclonal antibodies (mAbs) with strong thyroid-stimulating properties. Administration of the mAbs KSAb1 (IgG2b) or KSAb2 (IgG2a), which have similar stimulating properties but different TSH-binding blocking activity, resulted in significantly elevated serum thyroxine (T(4)) levels and thyroid hyperplasia. After the first injection, an initial surge then fall in serum T(4) levels was followed by sustained elevated levels with subsequent injections for at least 63 days. Examination of KSAb1 and KSAb2 serum bioactivity showed that the accumulation of the TSAbs in serum was related to their subclass half-lives. The thyroid glands were enlarged and histological examination showed hyperplastic follicles, with minimal accompanying thyroid inflammation. Our results show that chronic in vivo administration of mAbs with strong thyroid-stimulating activity resulted in elevated T(4) levels, suggesting persistent stimulation without receptor desensitization, giving a potential explanation for the sustained hyperthyroid status in patients with Graves' disease. Moreover, despite the presence of HLA disease susceptibility alleles and the autoimmune prone NOD background genes, chronic stimulation of the thyroid gland did not lead to immune cell-mediated follicular destruction, suggesting the persistence of immunoregulatory influences to suppress autoimmunity.

  1. Elucidating the nature and mechanism of tic improvement in tourette syndrome: a pilot study.

    Science.gov (United States)

    Shprecher, David R; Gannon, Keenan; Agarwal, Nivedita; Shi, Xianfeng; Anderson, Jeffrey S

    2014-01-01

    For unclear reasons, many Tourette syndrome (TS) children report near-complete tic remission by young adulthood. Immature maturation of brain networks, observed with resting-state functional MRI (rs-fc-MRI) in adolescents and adults with TS, might evolve to a mature pattern in adults who experience tic improvement or remission. We explored the feasibility of testing this hypothesis in our population of young adult TS males, each with prior clinical assessments completed during childhood as part of a separate TS Association Genetics Consortium study. A total of 10 TS males (off tic suppressing drugs for at least 6 months) aged 19-32 years, mean follow-up interval 7.5 (2 to 13) years, and 11 neurologically normal controls were enrolled and underwent 3-Tesla structural and rs-fc-MRI sequences. The mean change in Yale Global Tic Severity Scale (YGTSS) was -31.5% (total) and -26.6% (YGTSS motor+vocal). Two subjects reported resolution of tic-related disability, with drops from mean 45 to 16.5 (YGTSS-total) and 25 to 11.5 (YGTSS motor+vocal.). Rs-fc-MRI revealed significantly increased connectivity between the ipsilateral anterior and mid cingulate cortex and striatum, increased connectivity between local connections, and decreased connectivity between more distant connections; representing an immature connectivity pattern. Similar to previous reports, we found immature patterns of functional connectivity in adult TS subjects. Despite a lack of complete tic remission, two subjects exhibited dramatic drops in tic severity that correlated with tic-related disability improvement. More work is needed to elucidate the mechanism of such dramatic improvement in TS.

  2. Plasma experiments elucidative for challenging problems investigated in other branches of science

    International Nuclear Information System (INIS)

    Sanduloviciu, M.; Popescu, S.

    2001-01-01

    Driving away from thermal equilibrium a plasma initially in an asymptotic stable state it is possible to identify the succession of the physical processes that form, as a whole, a new scenario of self-organization able to explain, besides the challenging problems of non-equilibrium physics, also some of the today not solved essential problems of the chemical and biological sciences. Thus, plasma experiments have revealed the presence of a local self-enhancement mechanism associated with long-range inhibition that explains pattern formation in general. Two successively produced instabilities originated in a positive feedback mechanism were identified to be at the origin of the spatial and spatial-temporal patterns, respectively. This feedback mechanism comprises a self-enhancing mechanism of the production of positive ions complemented by the creation of a net negative space charge by accumulation of electrons that have lost their kinetic energy in neutral excitations. The informational content concerning self-organization revealed by the plasma experiments suggests the presence of a new physical basis for the behavior of the systems working as differential negative resistance, but also new information on the actual cause of the anomalous transport of particles and energy. These results present special interest in solid state physics where the mechanism of current instabilities observed in semiconductors is today a non-conclusively solved problem. Anomalous transport of particles and energy is today a challenging problem of high energy physics because it is considered as the principal cause that impedes the improvement of the economical performances of fusion devices. Since all chemical and biological phenomena involve, at least, physical processes, the scenario of self-organization identified in plasma could be elucidative for understanding the phenomena, as for instance, the pattern formation in chemical media, but also the spontaneous self-assembling of the

  3. Elucidation of the Synthetic Mechanism of Acylceramide, an Essential Lipid for Skin Barrier Function.

    Science.gov (United States)

    Ohno, Yusuke

    2017-01-01

    The primary function of the skin is to act as a permeability barrier that prevents water loss from inside the body and external invasion such as by pathogens, harmful substances, and allergens. Lipids play a critical role in skin barrier formation by forming multi-lamellar structures in the stratum corneum, the outermost cell layer of the epidermis. Ceramide, the backbone of sphingolipids, accounts for more than 50% of the stratum corneum lipids. Acylceramides are epidermis-specific ceramide species essential for skin barrier formation. Decreases in acylceramide levels and changes in ceramide composition and chain-length are associated with such cutaneous disorders as ichthyosis, atopic dermatitis, and psoriasis. Acylceramide consists of a long-chain base and an amide-linked ultra-long-chain fatty acid (ULCFA, 28-36 carbon chain), which is ω-hydroxylated and esterified with linoleic acid. Although the molecular mechanism by which acylceramide is generated has not been fully understood for decades, we recently identified two genes, CYP4F22 and PNPLA1, involved in acylceramide synthesis and elucidated the entire biosynthetic pathway of acylceramide: the synthesis of ULCFA by ELOVL1 and ELOVL4, ω-hydroxylation of the ULCFA by CYP4F22, amide-bond formation with a long-chain base by CERS3, and transacylation of linoleic acid from triacylglycerol to ω-hydroxyceramide by PNPLA1 to generate acylceramide. CYP4F22 and PNPLA1 are the causative genes of ichthyosis. We demonstrated that mutations of CYP4F22 or PNPLA1 markedly reduced acylceramide production. Our recent findings provide important insights into the molecular mechanisms of skin barrier formation and of ichthyosis pathogenesis.

  4. Interstitial Cystitis – Elucidation of Psychophysiologic and Autonomic Characteristics (the ICEPAC Study): design and methods

    Science.gov (United States)

    Chelimsky, Thomas; Chelimsky, Gisela; McCabe, N Patrick; Louttit, Megan; Hijaz, Adonis; Mahajan, Sangeeta; Sanses, Tatiana; Buffington, CA Tony; Fenton, Bradford; Janicki, Thomas; Ialacci, Sarah; Veizi, Elias; Zhang, Di; Daneshgari, Firouz; Elston, Robert; Janata, Jeffrey

    2014-01-01

    Background and purpose Interstitial cystitis/bladder pain syndrome (IC/BPS) is relatively common and associated with severe pain, yet effective treatment remains elusive. Research typically emphasized the bladder’s role, but given the high presence of systemic comorbidities, the authors hypothesized a pathophysiologic nervous system role. This paper reports the methodology and approach to study the nervous system in women with IC/BPS. The study compares neurologic, urologic, gynecologic, autonomic, gastrointestinal, and psychological features of women with IC/BPS, their female relatives, women with myofascial pelvic pain (MPP), and healthy controls to elucidate the role of central and peripheral processing. Methods and results In total, 228 women (76 IC/BPS, 76 MPP, 38 family members, and 38 healthy controls) will be recruited. Subjects undergo detailed screening, structured neurologic examination of limbs and pelvis, tender point examination, autonomic testing, electrogastrography, and assessment of comorbid functional dysautonomias. Interpreters are blinded to subject classification. Psychological and stress response characteristics are examined with assessments of stress, trauma history, general psychological function, and stress response quantification. As of December 2012, data collection is completed for 25 healthy controls, 33 IC/BPS ± MPP, eight MPP, and three family members. Recruitment rate is accelerating and strategies emphasize maintaining and encouraging investigator participation in study science, internet advertising, and presentations to pelvic pain support groups. Conclusion The study represents a comprehensive, interdisciplinary approach to sampling autonomic and psychophysiologic characteristics of women with IC/BPS. Despite divergent opinions on study methodologies based on specialty experiences, the study has proven feasible to date and different perspectives have proved to be one of the greatest study strengths. PMID:24855387

  5. Elucidating the Nature and Mechanism of Tic Improvement in Tourette Syndrome: A Pilot Study

    Directory of Open Access Journals (Sweden)

    David Shprecher

    2014-04-01

    Full Text Available Background: For unclear reasons, many Tourette syndrome (TS children report near‐complete tic remission by young adulthood. Immature maturation of brain networks, observed with resting‐state functional MRI (rs‐fc‐MRI in adolescents and adults with TS, might evolve to a mature pattern in adults who experience tic improvement or remission. We explored the feasibility of testing this hypothesis in our population of young adult TS males, each with prior clinical assessments completed during childhood as part of a separate TS Association Genetics Consortium study. Methods: A total of 10 TS males (off tic suppressing drugs for at least 6 months aged 19–32 years, mean follow‐up interval 7.5 (2 to 13 years, and 11 neurologically normal controls were enrolled and underwent 3‐Tesla structural and rs‐fc‐MRI sequences. Results: The mean change in Yale Global Tic Severity Scale (YGTSS was −31.5% (total and −26.6% (YGTSS motor+vocal. Two subjects reported resolution of tic‐related disability, with drops from mean 45 to 16.5 (YGTSS‐total and 25 to 11.5 (YGTSS motor+vocal.. Rs‐fc‐MRI revealed significantly increased connectivity between the ipsilateral anterior and mid cingulate cortex and striatum, increased connectivity between local connections, and decreased connectivity between more distant connections; representing an immature connectivity pattern.Discussion: Similar to previous reports, we found immature patterns of functional connectivity in adult TS subjects. Despite a lack of complete tic remission, two subjects exhibited dramatic drops in tic severity that correlated with tic‐related disability improvement. More work is needed to elucidate the mechanism of such dramatic improvement in TS.

  6. Preparation of zein nanoparticles by using solution-enhanced dispersion with supercritical CO2 and elucidation with computational fluid dynamics.

    Science.gov (United States)

    Li, Sining; Zhao, Yaping

    2017-01-01

    Nanoparticles have attracted more and more attention in the medicinal field. Zein is a biomacromolecule and can be used as a carrier for delivering active ingredients to prepare controlled release drugs. In this article, we presented the preparation of zein nanoparticles by solution-enhanced dispersion by supercritical CO 2 (SEDS) approach. Scanning electron microscopy and transmission electron microscopy were applied to characterize the size and morphology of the obtained particles. The nozzle structure and the CO 2 flow rate greatly affected the morphology and the size of the particles. The size of zein was able to be reduced to 50-350 nm according to the different conditions. The morphologies of the resultant zein were either sphere or the filament network consisted of nanoparticles. The influence of the nozzle structure and the CO 2 flow rate on the velocity field was elucidated by using computational fluid dynamics. The nozzle structure and the CO 2 flow rate greatly affected the distribution of the velocity field. However, a similar velocity field could also be obtained when the nozzle structure or the CO 2 flow rate, or both were different. Therefore, the influence of the nozzle structure and the CO 2 flow rate on the size and morphology of the particles, can boil down to the velocity field. The results demonstrated that the velocity field can be a potential criterion for producing nanoparticles with controllable morphology and size, which is useful to scale-up the SEDS process.

  7. Elucidation of the fluctuation history of cosmic radiation and global environmental using AMS

    International Nuclear Information System (INIS)

    Horiuchi, Kazuho

    2008-01-01

    Recently, accuracy of AMS has further been raised in trace amounts of sample. Besides application of 14 C to the age estimation, it has been able to restore in detail the past fluctuation of cosmic radiation strength using the other radioactive isotopes ( 10 Be, 36 Cl etc) in environmental samples and to elucidate the correlation of this with the fluctuation of climate and environment. In this report, the attempts to elucidate the fluctuation history of cosmic radiation and global environment with ice cores using AMS are presented. (M.H.)

  8. Elucidating compound mechanism of action by network perturbation analysis | Office of Cancer Genomics

    Science.gov (United States)

    Genome-wide identification of the mechanism of action (MoA) of small-molecule compounds characterizing their targets, effectors, and activity modulators represents a highly relevant yet elusive goal, with critical implications for assessment of compound efficacy and toxicity. Current approaches are labor intensive and mostly limited to elucidating high-affinity binding target proteins.

  9. Marker assisted elucidation of the origin of 2n-gametes in diploid potato

    NARCIS (Netherlands)

    Bastiaanssen, H.J.M.

    1997-01-01

    This thesis describes the selection and evaluation of diploid potato clones (2n=2x=24) that produce unreduced or 2n-gametes with 24 chromosomes instead of the normal reduced n-gametes with 12 chromosomes. To elucidate the modes of origin of the 2n-gametes, the progenies derived from such gametes

  10. Interstitial Cystitis – Elucidation of Psychophysiologic and Autonomic Characteristics (the ICEPAC Study: design and methods

    Directory of Open Access Journals (Sweden)

    Chelimsky T

    2014-05-01

    Full Text Available Thomas Chelimsky,1 Gisela Chelimsky,1 N Patrick McCabe,2 Megan Louttit,3 Adonis Hijaz,3 Sangeeta Mahajan,3 Tatiana Sanses,3 CA Tony Buffington,4 Bradford Fenton,5 Thomas Janicki,3 Sarah Ialacci,2 Elias Veizi,3 Di Zhang,2 Firouz Daneshgari,2,3 Robert Elston,2 Jeffrey Janata2,31The Medical College of Wisconsin, Departments of Neurology and Gastroenterology, Milwaukee, WI, 2Case Western Reserve University, Department of Neurology, Cleveland, OH, 3University Hospitals Case Medical Center, School of Medicine, Cleveland, OH, 4The Ohio State University, Department of Veterinary Clinical Sciences, Columbus, OH, 5Summa Health System, Department of Gynecology, Akron, OH, USABackground and purpose: Interstitial cystitis/bladder pain syndrome (IC/BPS is relatively common and associated with severe pain, yet effective treatment remains elusive. Research typically emphasized the bladder's role, but given the high presence of systemic comorbidities, the authors hypothesized a pathophysiologic nervous system role. This paper reports the methodology and approach to study the nervous system in women with IC/BPS. The study compares neurologic, urologic, gynecologic, autonomic, gastrointestinal, and psychological features of women with IC/BPS, their female relatives, women with myofascial pelvic pain (MPP, and healthy controls to elucidate the role of central and peripheral processing.Methods and results: In total, 228 women (76 IC/BPS, 76 MPP, 38 family members, and 38 healthy controls will be recruited. Subjects undergo detailed screening, structured neurologic examination of limbs and pelvis, tender point examination, autonomic testing, electrogastrography, and assessment of comorbid functional dysautonomias. Interpreters are blinded to subject classification. Psychological and stress response characteristics are examined with assessments of stress, trauma history, general psychological function, and stress response quantification. As of December 2012, data

  11. An analytical approach to elucidate the mechanism of grain refinement in calcium added Mg-Al alloys

    International Nuclear Information System (INIS)

    Nagasivamuni, B.; Ravi, K.R.

    2015-01-01

    Highlights: • Minor additions of Ca (<0.2%) refines the grain structure in Mg-(3, 6 and 9)Al alloys. • Analytical model elucidate that nucleation potency is enhanced after Ca addition. • Ternary Mg-Al-xCa growth restriction values (Q t ) are computed using Scheil equations. • Grain size predictions elucidate that nucleation events dominate grain refinement. • Growth restriction due to the higher Ca addition on grain refinement is not significant. - Abstract: The present study investigates the grain refinement of Mg-3Al, Mg-6Al and Mg-9Al alloys by calcium addition. The maximum reduction in grain size has been observed at 0.2% Ca addition in Mg-Al alloys, in which any further addition (up to 0.4%) has marginal improvement in grain refinement. The mechanism associated with the grain refinement of Mg-Al alloys by Ca addition is discussed in terms of growth restriction factor (Q) and constitutional undercooling (ΔT CS ) using analytical model. The influence of growth restriction factor (Q) on the final grain size of Ca-added Mg-Al alloys are calculated with the help analytical model by assuming that the number of nucleant particles is not altered through Ca addition. For accurate grain size calculations, the value of Q has been estimated with reliable thermodynamic database using Scheil solidification simulation. The comparison of predicted and experimental grain size results indicate that constitutional undercooling activation of nucleation events plays dominant role in grain refinement in Mg-Al alloys by calcium addition, whereas the increase in growth restriction value has negligible effect

  12. Expanding the concepts and tools of metabolic engineering to elucidate cancer metabolism.

    Science.gov (United States)

    Keibler, Mark A; Fendt, Sarah-Maria; Stephanopoulos, Gregory

    2012-01-01

    The metabolic engineer's toolbox, comprising stable isotope tracers, flux estimation and analysis, pathway identification, and pathway kinetics and regulation, among other techniques, has long been used to elucidate and quantify pathways primarily in the context of engineering microbes for producing small molecules of interest. Recently, these tools are increasingly finding use in cancer biology due to their unparalleled capacity for quantifying intracellular metabolism of mammalian cells. Here, we review basic concepts that are used to derive useful insights about the metabolism of tumor cells, along with a number of illustrative examples highlighting the fundamental contributions of these methods to elucidating cancer cell metabolism. This area presents unique opportunities for metabolic engineering to expand its portfolio of applications into the realm of cancer biology and help develop new cancer therapies based on a new class of metabolically derived targets. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  13. Combining pharmacophore fingerprints and PLS-discriminant analysis for virtual screening and SAR elucidation

    DEFF Research Database (Denmark)

    Askjær, Sune; Langgård, Morten

    2008-01-01

    the lead optimization toward a final drug candidate. This paper presents a combined approach to solving these two problems of ligand-based virtual screening and elucidation of SAR based on interplay between pharmacophore fingerprints and interpretation of PLS-discriminant analysis (PLS-DA) models....... The virtual screening capability of the PLS-DA method is compared to group fusion maximum similarity searching in a test using four graph-based pharmacophore fingerprints over a range of 10 diverse targets. The PLS-DA method was generally found to do better than the Smax method. The GpiDAPH3 and PCH...... fingerprints proved superior to the TGT and TGD fingerprints. Examples of SAR elucidation based on PLS-DA model interpretation of model coefficients using a reversible pharmacophore fingerprint are given. In addition, we tested the hypothesis that feature combinations coming from the analysis of two...

  14. Active Interaction Mapping as a tool to elucidate hierarchical functions of biological processes.

    Science.gov (United States)

    Farré, Jean-Claude; Kramer, Michael; Ideker, Trey; Subramani, Suresh

    2017-07-03

    Increasingly, various 'omics data are contributing significantly to our understanding of novel biological processes, but it has not been possible to iteratively elucidate hierarchical functions in complex phenomena. We describe a general systems biology approach called Active Interaction Mapping (AI-MAP), which elucidates the hierarchy of functions for any biological process. Existing and new 'omics data sets can be iteratively added to create and improve hierarchical models which enhance our understanding of particular biological processes. The best datatypes to further improve an AI-MAP model are predicted computationally. We applied this approach to our understanding of general and selective autophagy, which are conserved in most eukaryotes, setting the stage for the broader application to other cellular processes of interest. In the particular application to autophagy-related processes, we uncovered and validated new autophagy and autophagy-related processes, expanded known autophagy processes with new components, integrated known non-autophagic processes with autophagy and predict other unexplored connections.

  15. Applying iPSCs for Preserving Endangered Species and Elucidating the Evolution of Mammalian Sex Determination.

    Science.gov (United States)

    Honda, Arata

    2018-04-06

    The endangered species Tokudaia osimensis has the unique chromosome constitution of 2n = 25, with an XO/XO sex chromosome configuration (2n = 25; XO). There is urgency to preserve this species and to elucidate the regulator(s) that can discriminate the males and females arising from the indistinguishable sex chromosome constitution. However, it is not realistic to examine this rare animal species by sacrificing individuals. Recently, true naïve induced pluripotent stem cells were successfully generated from a female T. osimensis, and the sexual plasticity of its germ cells was elucidated. This achievement constitutes the basis of an attractive research area, including embryonic fate determination, sex determination, and factor(s) that can replace the Y chromosome. In this essay, concrete strategies to conserve rare animal species and to reveal their specific characteristics using other compatible and abundant animals are proposed. © 2018 WILEY Periodicals, Inc.

  16. Prevention of Ovarian High Grade Serous Carcinoma by Elucidating Its Early Changes

    Science.gov (United States)

    2016-10-01

    pathology. Springer 2015 25 ▪ Other publications, conference papers, and presentations. Abstracts S George , A Milea, N Salman and P Shaw...11-2-0230) Title: Prevention of Ovarian High-Grade Serous Carcinoma by Elucidating Its Early Change 2011-Current 1. George SH, Greenaway J, Milea...Cancer Res 2012, 18:4334-44. PMID: 22753593 4 11. George SH, Milea A, Shaw P: Proliferation in the normal FTE is a hallmark of the follicular phase

  17. Elucidating the mechanisms of nickel compound uptake: A review of particulate and nano-nickel endocytosis and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Alexandra; Costa, Max, E-mail: Max.Costa@nyumc.org

    2012-04-01

    Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses — most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanism of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties.

  18. Radioimmunoassay of thyrotropin concentrated from serum

    International Nuclear Information System (INIS)

    Nisula, B.C.; Louvet, J.P.

    1978-01-01

    A method for concentrating human TSH (hTSH) from serum for use in RIAs is described. The method takes advantage of the affinity of the plant lectin, concanavalin A, for the carbohydrate portion of the hTSH molecule. The hTSH from 2.5 ml serum was adsorbed to concanavalin A covalently linked to sepharose and then radioimmunoassayed using the hTSH antiserum and hTSH for iodination distributed by the National Pituitary Agency. For the RIA standard curve, the hTSH reference preparation was concentrated from a serum wwith undetectable hTSH in order to correct for recovery and to control for nonspecific effects. The percentage of serum hTSH extracted from 2.5 ml serum with the concentration procedure was 76.6 +- 3.4% (mean +- SD). The coefficient of correlation between serum hTSH, determined with the concentration procedure, and serum hTSH determined without was 0.979 (P < 0.001). Over 95% of normal adult men and women had detectable levels of serum hTSH, ranging from < 0.56 to 4.0 μU/ml. The mean of detectable serum hTSH levels in normal adult women (n = 11) was 1.54 +- 1.03 μU/ml (mean +- SD) and in normal men (n = 9) was 2.02 +- 1.15 μU/ml (mean +- SD). Clinically hyperthyroid patients with diffuse and nodular toxic goiters (n = 8) and patients with hypothyroidism secondary to pituitary disease (n = 6), four of whom were taking replacement doses of thyroid hormone, had undetectable serum hTSH levels. Serum hTSH in patients with primary hypothyroidism uniformly exceeded the normal range. This hTSH concentrating procedure enhances the effective sensitivity and, therefore, the clinical utility of the RIA for hTSH in serum

  19. RESEARCH CONCERNING THE GENETIC STRUCTURE OF ROMANIAN SIMENTAL AND MARAMURES BROWN BREEEDS AT THE PITUITARY TRANSCRIPTION FACTOR LOCUS

    Directory of Open Access Journals (Sweden)

    VIORICA COSIER

    2008-05-01

    Full Text Available Pituitary transcription factor Pit-1, which belongs to a large POU domain family is a positive regulatory factor of growth hormone, prolactin and thyrotropin β-subunit in the mammalian pituitary. Therefore, the gene encoding Pit-1 was chosen as a candidate gene to investigate its association with lactation performance in cattle. The present study was carried out to establish the genetic structure at this locus in two Romanian cattle breeds: Romanian Simmental and Maramures Brown, to establish the possible association between genotype and milk yield and conformation traits. A strategy employing polymerase chain reaction was used to amplify a 1355- pb fragment from blood DNA and digestion with HinfI enzyme and the genetic structure was estimated for both breeds.

  20. Recent advances in the elucidation of enzymatic function in natural product biosynthesis.

    Science.gov (United States)

    Tan, Gao-Yi; Deng, Zixin; Liu, Tiangang

    2015-01-01

    With the successful production of artemisinic acid in yeast, the promising potential of synthetic biology for natural product biosynthesis is now being realized. The recent total biosynthesis of opioids in microbes is considered to be another landmark in this field. The importance and significance of enzymes in natural product biosynthetic pathways have been re-emphasized by these advancements. Therefore, the characterization and elucidation of enzymatic function in natural product biosynthesis are undoubtedly fundamental for the development of new drugs and the heterologous biosynthesis of active natural products. Here, discoveries regarding enzymatic function in natural product biosynthesis over the past year are briefly reviewed.

  1. Elucidating determinants of aerosol composition through particle-type-based receptor modeling

    Directory of Open Access Journals (Sweden)

    M. L. McGuire

    2011-08-01

    Full Text Available An aerosol time-of-flight mass spectrometer (ATOFMS was deployed at a semi-rural site in southern Ontario to characterize the size and chemical composition of individual particles. Particle-type-based receptor modelling of these data was used to investigate the determinants of aerosol chemical composition in this region. Individual particles were classified into particle-types and positive matrix factorization (PMF was applied to their temporal trends to separate and cross-apportion particle-types to factors. The extent of chemical processing for each factor was assessed by evaluating the internal and external mixing state of the characteristic particle-types. The nine factors identified helped to elucidate the coupled interactions of these determinants. Nitrate-laden dust was found to be the dominant type of locally emitted particles measured by ATOFMS. Several factors associated with aerosol transported to the site from intermediate local-to-regional distances were identified: the Organic factor was associated with a combustion source to the north-west; the ECOC Day factor was characterized by nearby local-to-regional carbonaceous emissions transported from the south-west during the daytime; and the Fireworks factor consisted of pyrotechnic particles from the Detroit region following holiday fireworks displays. Regional aerosol from farther emissions sources was reflected through three factors: two Biomass Burning factors and a highly chemically processed Long Range Transport factor. The Biomass Burning factors were separated by PMF due to differences in chemical processing which were in part elucidated by the passage of two thunderstorm gust fronts with different air mass histories. The remaining two factors, ECOC Night and Nitrate Background, represented the night-time partitioning of nitrate to pre-existing particles of different origins. The distinct meteorological conditions observed during this month-long study in the summer of 2007

  2. Second generation sequencing for elucidating the diversity of bacteria and plasmids in soil

    DEFF Research Database (Denmark)

    Holmsgaard, Peter Nikolai

    and increased the relative abundance of Gammaproteobacteria. Additionally, a high abundance of IncP-1, IncP-7, IncP-9, IncQ and IncW plasmids and class I and II integrons were detected. Amplicon pyrosequencing of the IncP-1 plasmids showed an increase in relative abundance of the IncP-1β and decrease of IncP-1ε...... during the season. In the sixth paper, unspecific DNA amplification using multiple displacement amplification was shown to preferentially amplify DNA from some bacterial species over others. In conclusion, papers II to V use, among other things, amplicon pyrosequencing to elucidate the bacterial...

  3. Elucidating transmission dynamics and host-parasite-vector relationships for rodent-borne Bartonella spp. in Madagascar

    Directory of Open Access Journals (Sweden)

    Cara E. Brook

    2017-09-01

    Full Text Available Bartonella spp. are erythrocytic bacteria transmitted via arthropod vectors, which infect a broad range of vertebrate hosts, including humans. We investigated transmission dynamics and host-parasite-vector relationships for potentially zoonotic Bartonella spp. in invasive Rattus rattus hosts and associated arthropod ectoparasites in Madagascar. We identified five distinct species of Bartonella (B. elizabethae 1, B. elizabethae 2, B. phoceensis 1, B. rattimassiliensis 1, and B. tribocorum 1 infecting R. rattus rodents and their ectoparasites. We fit standard epidemiological models to species-specific age-prevalence data for the four Bartonella spp. with sufficient data, thus quantifying age-structured force of infection. Known zoonotic agents, B. elizabethae 1 and 2, were best described by models exhibiting high forces of infection in early age class individuals and allowing for recovery from infection, while B. phoceensis 1 and B. rattimassiliensis 1 were best fit by models of lifelong infection without recovery and substantially lower forces of infection. Nested sequences of B. elizabethae 1 and 2 were recovered from rodent hosts and their Synopsyllus fonquerniei and Xenopsylla cheopsis fleas, with a particularly high prevalence in the outdoor-dwelling, highland-endemic S. fonquerniei. These findings expand on force of infection analyses to elucidate the ecological niche of the zoonotic Bartonella elizabethae complex in Madagascar, hinting at a potential vector role for S. fonquerniei. Our analyses underscore the uniqueness of such ecologies for Bartonella species, which pose a variable range of potential zoonotic threats.

  4. Application of ion beams for elucidation of functions in living bodies

    International Nuclear Information System (INIS)

    Fujimura, Takashi; Ishihara, Noriyuki; Omichi, Hideki; Tamura, Mamoru; Omasa, Kenji; Sasaki, Yasuhito.

    1992-01-01

    The Japan Atomic Energy Research Institute (JAERI) is planning a research project, 'Application of Ion Beams for Elucidation of Functions in Living Bodies'. This project is characterized by the non-invasive or non-destructive measurement for living plants, animals and microorganisms and divided into two fields. The first field is the utilization of positron emitters prepared with cyclotron. The development of a new method which combines PET with other methods like near infrared region spectroscopy or magnetic resonance spectroscopy is urgently desired. Positron emitters can be also applied to elucidate the functions of plants. The second field is in situ and non-invasive optical measurement of living bodies or cells irradiated with ion beams. Active species produced by irradiation could induce physiological and biochemical reactions in living bodies or cells. To actualize this project, a group of non-invasive measuring equipments for the first field will be set in a new building next to ion irradiation facilities (TIARA, Takasaki Ion Accelerators for Advanced Radiation Application). For the second field, in situ and non-invasive optical measurement of living bodies or cells with be carried out in TIARA. (J.P.N.)

  5. Secretome analysis to elucidate metalloprotease-dependent ectodomain shedding of glycoproteins during neuronal differentiation.

    Science.gov (United States)

    Tsumagari, Kazuya; Shirakabe, Kyoko; Ogura, Mayu; Sato, Fuminori; Ishihama, Yasushi; Sehara-Fujisawa, Atsuko

    2017-02-01

    Many membrane proteins are subjected to limited proteolyses at their juxtamembrane regions, processes referred to as ectodomain shedding. Shedding ectodomains of membrane-bound ligands results in activation of downstream signaling pathways, whereas shedding those of cell adhesion molecules causes loss of cell-cell contacts. Secreted proteomics (secretomics) using high-resolution mass spectrometry would be strong tools for both comprehensive identification and quantitative measurement of membrane proteins that undergo ectodomain shedding. In this study, to elucidate the ectodomain shedding events that occur during neuronal differentiation, we establish a strategy for quantitative secretomics of glycoproteins released from differentiating neuroblastoma cells into culture medium with or without GM6001, a broad-spectrum metalloprotease inhibitor. Considering that most of transmembrane and secreted proteins are N-glycosylated, we include a process of N-glycosylated peptides enrichment as well as isotope tagging in our secretomics workflow. Our results show that differentiating N1E-115 neurons secrete numerous glycosylated polypeptides in metalloprotease-dependent manners. They are derived from cell adhesion molecules such as NCAM1, CADM1, L1CAM, various transporters and receptor proteins. These results show the landscape of ectodomain shedding and other secretory events in differentiating neurons and/or during axon elongation, which should help elucidate the mechanism of neurogenesis and the pathogenesis of neurological disorders. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  6. Elucidating Mechanisms of Molecular Recognition Between Human Argonaute and miRNA Using Computational Approaches

    KAUST Repository

    Jiang, Hanlun

    2016-12-06

    MicroRNA (miRNA) and Argonaute (AGO) protein together form the RNA-induced silencing complex (RISC) that plays an essential role in the regulation of gene expression. Elucidating the underlying mechanism of AGO-miRNA recognition is thus of great importance not only for the in-depth understanding of miRNA function but also for inspiring new drugs targeting miRNAs. In this chapter we introduce a combined computational approach of molecular dynamics (MD) simulations, Markov state models (MSMs), and protein-RNA docking to investigate AGO-miRNA recognition. Constructed from MD simulations, MSMs can elucidate the conformational dynamics of AGO at biologically relevant timescales. Protein-RNA docking can then efficiently identify the AGO conformations that are geometrically accessible to miRNA. Using our recent work on human AGO2 as an example, we explain the rationale and the workflow of our method in details. This combined approach holds great promise to complement experiments in unraveling the mechanisms of molecular recognition between large, flexible, and complex biomolecules.

  7. Elucidation of spin echo small angle neutron scattering correlation functions through model studies.

    Science.gov (United States)

    Shew, Chwen-Yang; Chen, Wei-Ren

    2012-02-14

    Several single-modal Debye correlation functions to approximate part of the overall Debey correlation function of liquids are closely examined for elucidating their behavior in the corresponding spin echo small angle neutron scattering (SESANS) correlation functions. We find that the maximum length scale of a Debye correlation function is identical to that of its SESANS correlation function. For discrete Debye correlation functions, the peak of SESANS correlation function emerges at their first discrete point, whereas for continuous Debye correlation functions with greater width, the peak position shifts to a greater value. In both cases, the intensity and shape of the peak of the SESANS correlation function are determined by the width of the Debye correlation functions. Furthermore, we mimic the intramolecular and intermolecular Debye correlation functions of liquids composed of interacting particles based on a simple model to elucidate their competition in the SESANS correlation function. Our calculations show that the first local minimum of a SESANS correlation function can be negative and positive. By adjusting the spatial distribution of the intermolecular Debye function in the model, the calculated SESANS spectra exhibit the profile consistent with that of hard-sphere and sticky-hard-sphere liquids predicted by more sophisticated liquid state theory and computer simulation. © 2012 American Institute of Physics

  8. Elucidation and modulation of glucocorticoid-induced apoptosis in acute lymphoblastic leukemia cells

    International Nuclear Information System (INIS)

    Eberhart, K.

    2011-01-01

    This thesis deals with the elucidation of the synergistic effect of the glucocorticoid dexamethasone and the metabolic modulator 2-deoxyglucose on apoptosis induction in two in vitro model systems of childhood acute lymphoblastic leukemia. 2-deoxyglucose accelerated the kinetics of, and increased the sensitivity to, glucocorticoid-induced apoptosis in two leukemia cell lines. In primary lymphocytes from healthy donors, in contrast, 2-deoxyglucose and dexamethasone did not act synergistically on apoptosis induction. To elucidate the molecular basis of the synergistic effect, glycolysis by means of glucose uptake, lactate production, ATP levels, glucose transporter and hexokinase expression and mitochondrial oxygen consumption was analyzed in treated vs. untreated cells. The study revealed a downregulation of gene expression of the glucose transporter GLUT1 and hexokinase 2 (HK2), release of HK2 from the outer mitochondrial membrane, as well as reduced glycolysis and mitochondrial respiration. Moreover, the analysis of the mitochondrial proteome by 2 dimensional differential gel electrophoresis after treatment with 2-deoxyglucose and dexamethasone revealed the regulation of several interesting candidate proteins involved in treatment related apoptosis. (author)

  9. Phase-locked signals elucidate circuit architecture of an oscillatory pathway.

    Directory of Open Access Journals (Sweden)

    Andreja Jovic

    2010-12-01

    Full Text Available This paper introduces the concept of phase-locking analysis of oscillatory cellular signaling systems to elucidate biochemical circuit architecture. Phase-locking is a physical phenomenon that refers to a response mode in which system output is synchronized to a periodic stimulus; in some instances, the number of responses can be fewer than the number of inputs, indicative of skipped beats. While the observation of phase-locking alone is largely independent of detailed mechanism, we find that the properties of phase-locking are useful for discriminating circuit architectures because they reflect not only the activation but also the recovery characteristics of biochemical circuits. Here, this principle is demonstrated for analysis of a G-protein coupled receptor system, the M3 muscarinic receptor-calcium signaling pathway, using microfluidic-mediated periodic chemical stimulation of the M3 receptor with carbachol and real-time imaging of resulting calcium transients. Using this approach we uncovered the potential importance of basal IP3 production, a finding that has important implications on calcium response fidelity to periodic stimulation. Based upon our analysis, we also negated the notion that the Gq-PLC interaction is switch-like, which has a strong influence upon how extracellular signals are filtered and interpreted downstream. Phase-locking analysis is a new and useful tool for model revision and mechanism elucidation; the method complements conventional genetic and chemical tools for analysis of cellular signaling circuitry and should be broadly applicable to other oscillatory pathways.

  10. Quantitative structure-activity relationship analysis to elucidate the clearance mechanisms of Tc-99m labeled quinolone antibiotics

    International Nuclear Information System (INIS)

    Salahinejad, M.; Mirshojaei, S.F.

    2016-01-01

    This study aims to establish molecular modeling methods for predicting the liver and kidney uptakes of Tc-99m labeled quinolone antibiotics. Some three-dimensional quantitative-activity relationships (3D-QSAR) models were developed using comparative molecular field analysis and grid-independent descriptors procedures. As a first report on 3D-QSAR modeling, the predicted liver and kidney uptakes for quinolone antibiotics were in good agreement with the experimental values. The obtained results confirm the importance of hydrophobic interactions, size and steric hindrance of antibiotic molecules in their liver uptakes, while the electrostatic interactions and hydrogen bonding ability have impressive effects on their kidney uptakes. (author)

  11. Fast in vitro hydrolytic degradation of polyester urethane acrylate biomaterials: Structure elucidation, separation and quantification of degradation products

    NARCIS (Netherlands)

    Ghaffar, A.; Verschuren, P.G.; Geenevasen, J.A.J.; Handels, T.; Berard, J.; Plum, B.; Dias, A.A.; Schoenmakers, P.J.; van der Wal, S.

    2011-01-01

    Synthetic biomaterials have evoked extensive interest for applications in the field of health care. Prior to administration to the body a quantitative study is necessary to evaluate their composition. An in vitro method was developed for the quick hydrolytic degradation of poly-2-hydroxyethyl

  12. Structure elucidation of cresylviolet perchlorate in polyvinylbutyral by the joint application of IR, FTIR, Raman, UV and visible spectroscopy.

    Science.gov (United States)

    Bayrakçeken, Fuat; Karaaslan, Ipek S; Erol, Berkant

    2007-09-01

    Infrared, Fourier transform infrared, Raman, UV absorption and emission spectra of cresylviolet perchlorate (CV) in polyvinylbutyral (PVB) were recorded in the region 1250-4000 cm(-1) at room temperature and assignments have been made for the observed absorption emission and Raman scattered lines.

  13. Isolation and structure elucidation of a new linoleiyl glycoside and flavones from the stem bark of Morus alba L.

    Directory of Open Access Journals (Sweden)

    Abuzer Ali

    2016-12-01

    Conclusion: The present work reports the isolation and characterization of new phytoconstituents which could be used as chromatographic fingerprinting markers for standardization and quality control parameters.

  14. Structural elucidation of direct analysis in real time ionized nerve agent simulants with infrared multiple photon dissociation spectroscopy

    NARCIS (Netherlands)

    Rummel, J.L.; Steill, J.D.; Oomens, J.; Contreras, C.S.; Pearson, W.L.; Szczepanski, J.; Powell, D.H.; Eyler, J.R.

    2011-01-01

    Infrared multiple photon dissociation (IRMPD) was used to generate vibrational spectra of ions produced with a direct analysis in real time (DART) ionization source coupled to a 4.7 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The location of protonation on the nerve agent

  15. Structural Elucidation of Direct Analysis in Real Time Ionized Nerve Agent Simulants with Infrared Multiple Photon Dissociation Spectroscopy

    NARCIS (Netherlands)

    Rummel, J. L.; Steill, J. D.; Oomens, J.; Contreras, C. S.; Pearson, W. L.; Szczepanski, J.; Powell, D. H.; Eyler, J. R.

    2011-01-01

    Infrared multiple photon dissociation (IRMPD) was used to generate vibrational spectra of ions produced with a direct analysis in real time (DART) ionization source coupled to a 4.7 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The location of protonation on the nerve agent

  16. Identification and structural elucidation of steroidal saponins from the root of Paris polyphylla by HPLC-ESI-QTOF-MS/MS.

    Science.gov (United States)

    Ling, Yun; Fu, Zhiwen; Zhang, Qing; Xu, Lingling; Liao, Liang

    2015-01-01

    The root of Paris polyphylla (RPP) is widely used as a traditional Chinese medicine for a long time due to the good properties of heat-clearing and detoxicating, detumescence, sedation, acesodyne and haemostasis. To clarify on the bioactive substances and ensure the safety in clinical medication, a feasible and accurate strategy was developed by applying the high-performance liquid chromatography coupled to electrospray ionisation and quadrupole time-of-flight-mass spectrometry (HPLC-ESI-QTOF-MS/MS). Separation was performed an Agilent poroshell 120 EC-C18 column (2.7 × 100 mm, i.d., 2.7 μm) with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase under gradient conditions. Based on the proposed strategy, 30 constituents, mainly including steroidal saponins, were characterised or tentatively identified, 2 of which were the first to be reported as the potential new steroidal saponins in RPP. In conclusion, the HPLC-ESI-QTOF-MS/MS is a feasible and credible technique to separate and identify steroidal saponins from botanical extracts.

  17. Antifungal Compounds Isolated from Smyrnium olusatrum L. Essential Oil, Growing Wild in Cephalonia, Greece. Chemical Analysis and Structure Elucidation

    Directory of Open Access Journals (Sweden)

    Gerasimia Tsasi

    2016-01-01

    Full Text Available The essential oils (EOs from the leaves and the flowers of Smyrnium olusatrum L. , growing wild in the island of Cephalonia (Greece, were analyzed by GC-FID and GC-MS. Fifty nine constituents, which accounted for 90.3% (fl and 97.1% (lvs of the oils, were identified. Furanodiene, g ermacrone and furanoeremophil-1-one were the major constituents in both essential oils; they were also isolated from the flowers essential oil and identified using spectroscopic methods, ie. 1D and 2D NMR, GC-MS . In addition b -myrcene ( 11.7% and b -phellandrene (5.2% were main constituents in the essential oil of the leaves. The essential oils and the pure isolates were evaluated for antifungal activity against Aspergillus fumigatus , A. versicolor, A. ochraceus, A. niger, Trichoderma viride, Penicillium funiculosum, P. ochrochloron, P. verucosum var. cyclopium by using the microdilution method and proved to possess significant antifungal effect. Among them, (+ furanoeremophil-1-one was particularly active with MIC values in the range of 0.0008-0.125 mg/mL and MFC values of 0.025-0.050 mg/mL and proved more effective than the commercial mycotics ketoconazole and bifonazole used as positive controls.

  18. Indoleamine 2,3-dioxygenase inhibitors isolated from the sponge Xestospongia vansoesti: structure elucidation, analogue synthesis, and biological activity.

    Science.gov (United States)

    Centko, Ryan M; Steinø, Anne; Rosell, Federico I; Patrick, Brian O; de Voogd, Nicole; Mauk, A Grant; Andersen, Raymond J

    2014-12-19

    Two new IDO inhibitory meroterpenoids, xestolactone A (1) and xestosaprol O (2), have been isolated from the sponge Xestospongia vansoesti. Xestolactone A (1) has an unprecedented degraded meroterpenoid carbon skeleton. A short synthesis of the xestosaprol O (2) analogues 3 and 4 features the application of a rarely used photochemical coupling reaction. Synthetic analogue 3 is ∼40 times more potent than the inspirational natural product 2.

  19. Structure Elucidation and Activity of Kolossin A, the D-/L-Pentadecapeptide Product of a Giant Nonribosomal Peptide Synthetase.

    Science.gov (United States)

    Bode, Helge B; Brachmann, Alexander O; Jadhav, Kirtikumar B; Seyfarth, Lydia; Dauth, Christina; Fuchs, Sebastian W; Kaiser, Marcel; Waterfield, Nick R; Sack, Holger; Heinemann, Stefan H; Arndt, Hans-Dieter

    2015-08-24

    The largest continuous bacterial nonribosomal peptide synthetase discovered so far is described. It consists of 15 consecutive modules arising from an uninterrupted, fully functional gene in the entomopathogenic bacterium Photorhabdus luminescens. The identification of its cryptic biosynthesis product was achieved by using a combination of genome analysis, promoter exchange, isotopic labeling experiments, and total synthesis of a focused collection of peptide candidates. Although it belongs to the growing class of D-/ L-peptide natural products, the encoded metabolite kolossin A was found to be largely devoid of antibiotic activity and is likely involved in interspecies communication. A stereoisomer of this peculiar natural product displayed high activity against Trypanosoma brucei rhodesiense, a recalcitrant parasite that causes the deadly disease African sleeping sickness. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Structural characteristics of the molecular species of tetraacylglycerols in lesquerella (Physaria fendleri) oil elucidated by mass spectrometry

    Science.gov (United States)

    Tetraacylglycerols (triacylglycerol estolides) contain an acylacyl chain (one fatty acid attached to the hydroxyl group of another fatty acid attached to the glycerol backbone) and have different physical properties from those of triacylglycerols. Tetraacylglycerols can be used in industry such as t...

  1. Coupling of wet chemistry methods and spectroscopic data for elucidating composition and structure of purified condensed tannins

    Science.gov (United States)

    Condensed tannins (CTs) consist of oligomers and polymers of flavan-3-ol subunits varying in hydroxylation patterns, cis- and trans-configuration of C-ring substituents, interflavan bond connections, mean degree of polymerization (mDP), and extent of esterification. Robust analytical methods to dete...

  2. Elucidating the design principles of photosynthetic electron-transfer proteins by site-directed spin labeling EPR spectroscopy.

    Science.gov (United States)

    Ishara Silva, K; Jagannathan, Bharat; Golbeck, John H; Lakshmi, K V

    2016-05-01

    Site-directed spin labeling electron paramagnetic resonance (SDSL EPR) spectroscopy is a powerful tool to determine solvent accessibility, side-chain dynamics, and inter-spin distances at specific sites in biological macromolecules. This information provides important insights into the structure and dynamics of both natural and designed proteins and protein complexes. Here, we discuss the application of SDSL EPR spectroscopy in probing the charge-transfer cofactors in photosynthetic reaction centers (RC) such as photosystem I (PSI) and the bacterial reaction center (bRC). Photosynthetic RCs are large multi-subunit proteins (molecular weight≥300 kDa) that perform light-driven charge transfer reactions in photosynthesis. These reactions are carried out by cofactors that are paramagnetic in one of their oxidation states. This renders the RCs unsuitable for conventional nuclear magnetic resonance spectroscopy investigations. However, the presence of native paramagnetic centers and the ability to covalently attach site-directed spin labels in RCs makes them ideally suited for the application of SDSL EPR spectroscopy. The paramagnetic centers serve as probes of conformational changes, dynamics of subunit assembly, and the relative motion of cofactors and peptide subunits. In this review, we describe novel applications of SDSL EPR spectroscopy for elucidating the effects of local structure and dynamics on the electron-transfer cofactors of photosynthetic RCs. Because SDSL EPR Spectroscopy is uniquely suited to provide dynamic information on protein motion, it is a particularly useful method in the engineering and analysis of designed electron transfer proteins and protein networks. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016. Published by Elsevier B.V.

  3. Metagenomic and proteomic analyses to elucidate the mechanism of anaerobic benzene degradation

    Energy Technology Data Exchange (ETDEWEB)

    Abu Laban, Nidal [Helmholtz (Germany)

    2011-07-01

    This paper presents the mechanism of anaerobic benzene degradation using metagenomic and proteomic analyses. The objective of the study is to find out the microbes and biochemistry involved in benzene degradation. Hypotheses are proposed for the initial activation mechanism of benzene under anaerobic conditions. Two methods for degradation, molecular characterization and identification of benzene-degrading enzymes, are described. The physiological and molecular characteristics of iron-reducing enrichment culture are given and the process is detailed. Metagenome analysis of iron-reducing culture is presented using a pie chart. From the metagenome analysis of benzene-degrading culture, putative mobile element genes were identified in the aromatic-degrading configurations. Metaproteomic analysis of iron-reducing cultures and the anaerobic benzene degradation pathway are also elucidated. From the study, it can be concluded that gram-positive bacteria are involved in benzene degradation under iron-reducing conditions and that the catalysis mechanism of putative anaerobic benzene carboxylase needs further investigation.

  4. Fluid and electrolyte homeostasis during spaceflight: Elucidation of mechanisms in a primate

    Science.gov (United States)

    Churchill, Susanne

    1990-01-01

    Although it is now well accepted that exposure to the hypogravic environment of space induces a shift of fluid from the lower extremities toward the upper body, the actual physiological responses to this central volume expansion have not been well characterized. Because it is likely that the fluid and electrolyte response to hypogravity plays a critical role in the development of Cardiovascular Deconditioning, elucidation of these mechanisms is of critical importance. The goal of flight experiment 223, scheduled to fly on SLS-2, is the definition of the basic renal, fluid and electrolyte response to spaceflight in four instrumented squirrel monkeys. The studies were those required to support the development of flight hardware and optimal inflight procedures, and to evaluate a ground-based model for weightlessness, lower body positive pressure (LBPP).

  5. Study of application technology of ultra-high speed computer to the elucidation of complex phenomena

    International Nuclear Information System (INIS)

    Sekiguchi, Tomotsugu

    1996-01-01

    The basic design of numerical information library in the decentralized computer network was explained at the first step of constructing the application technology of ultra-high speed computer to the elucidation of complex phenomena. Establishment of the system makes possible to construct the efficient application environment of ultra-high speed computer system to be scalable with the different computing systems. We named the system Ninf (Network Information Library for High Performance Computing). The summary of application technology of library was described as follows: the application technology of library under the distributed environment, numeric constants, retrieval of value, library of special functions, computing library, Ninf library interface, Ninf remote library and registration. By the system, user is able to use the program concentrating the analyzing technology of numerical value with high precision, reliability and speed. (S.Y.)

  6. Elucidation of reaction mechanism for m -cresol hydrodeoxygenation over Fe based catalysts: A kinetic study

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Yongchun; Wang, Yong

    2017-09-01

    Fe based catalysts are promising for hydrodeoxygenation (HDO) of lignin derived phenolics due to their high selectivity for aromatics. In this work, the reaction mechanism of m-cresol HDO on Fe catalysts and the kinetic consequence with Pd addition were elucidated by examining the effect of H2, H2O and m-cresol pressures on toluene formation rate on Fe and PdFe catalysts. A direct CO bond cleavage mechanism is proposed for HDO catalysis on both Fe and PdFe catalysts, while Pd provides a facilitated reaction pathway at the PdFe interface and therefore promotes the catalysis on Fe without changing the high selectivity towards aromatics.

  7. Elucidating Tourette's syndrome: perspectives from hypnosis, attention and self-regulation.

    Science.gov (United States)

    Raz, Amir; Keller, Shari; Norman, Kim; Senechal, Diana

    2007-04-01

    Biological psychiatry favors drug treatment over non-pharmacological intervention and shapes the way clinicians both treat and understand Tourette's Syndrome (TS). However, drug treatments for TS involve side effects and are potentially toxic to the central nervous system. Moreover, current pharmacological treatments are largely ineffective and at best only provide a modest symptom reduction. In this paper, we describe how non-pharmacological treatments such as focused attention can modulate, reduce, or indeed entirely eliminate the symptoms of TS as well as elucidate the underlying neural mechanisms. Showing that the symptoms of TS are susceptible to self-regulatory interventions such as hypnosis, we propose that attentional training could be used to both treat the disorder and better understand it.

  8. Metabolic responses and "omics" technologies for elucidating the effects of heat stress in dairy cows.

    Science.gov (United States)

    Min, Li; Zhao, Shengguo; Tian, He; Zhou, Xu; Zhang, Yangdong; Li, Songli; Yang, Hongjian; Zheng, Nan; Wang, Jiaqi

    2017-06-01

    Heat stress (HS) negatively affects various industries that rely on animal husbandry, particularly the dairy industry. A better understanding of metabolic responses in HS dairy cows is necessary to elucidate the physiological mechanisms of HS and offer a new perspective for future research. In this paper, we review the current knowledge of responses of body metabolism (lipid, carbohydrate, and protein), endocrine profiles, and bovine mammary epithelial cells during HS. Furthermore, we summarize the metabolomics and proteomics data that have revealed the metabolite profiles and differentially expressed proteins that are a feature of HS in dairy cows. Analysis of metabolic changes and "omics" data demonstrated that HS is characterized by reduced lipolysis, increased glycolysis, and catabolism of amino acids in dairy cows. Here, analysis of the impairment of immune function during HS and of the inflammation that arises after long-term HS might suggest new strategies to ameliorate the effects of HS in dairy production.

  9. Exercise training on cardiovascular diseases: Role of animal models in the elucidation of the mechanisms

    Directory of Open Access Journals (Sweden)

    Bruno Rodrigues

    2017-05-01

    Full Text Available Abstract Cardiovascular diseases, which include hypertension, coronary artery disease/myocardial infarction and heart failure, are one of the major causes of disability and death worldwide. On the other hand, physical exercise acts in the preventionand treatment of these conditions. In fact, several experiments performed in human beings have demonstrated the efficiency of physical exercise to alter clinical signals observed in these diseases, such as high blood pressure and exercise intolerance. However, even if human studies demonstrated the clinical efficiency of physical exercise, most extensive mechanisms responsible for this phenomenon still have to be elucidated. In this sense, studies using animal models seem to be a good option to demonstrate such mechanisms. Therefore, the aims of the present study are describing the main pathophysiological characteristics of the animal models used in the study of cardiovascular diseases, as well as the main mechanismsassociated with the benefits of physical exercise.

  10. Elucidating and reprogramming Escherichia coli metabolisms for obligate anaerobic n-butanol and isobutanol production

    Energy Technology Data Exchange (ETDEWEB)

    Trinh, Cong T. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemical and Biomolecular Engineering

    2012-08-15

    Elementary mode (EM) analysis based on the constraint-based metabolic network modeling was applied to elucidate and compare complex fermentative metabolisms of Escherichia coli for obligate anaerobic production of n-butanol and isobutanol. The result shows that the n-butanol fermentative metabolism was NADH-deficient, while the isobutanol fermentative metabolism was NADH redundant. E. coli could grow and produce n-butanol anaerobically as the sole fermentative product but not achieve the maximum theoretical n-butanol yield. In contrast, for the isobutanol fermentative metabolism, E. coli was required to couple with either ethanol- or succinate-producing pathway to recycle NADH. To overcome these ''defective'' metabolisms, EM analysis was implemented to reprogram the native fermentative metabolism of E. coli for optimized anaerobic production of n-butanol and isobutanol through multiple gene deletion ({proportional_to}8-9 genes), addition ({proportional_to}6-7 genes), up- and downexpression ({proportional_to}6-7 genes), and cofactor engineering (e.g., NADH, NADPH). The designed strains were forced to couple both growth and anaerobic production of n-butanol and isobutanol, which is a useful characteristic to enhance biofuel production and tolerance through metabolic pathway evolution. Even though the n-butanol and isobutanol fermentative metabolisms were quite different, the designed strains could be engineered to have identical metabolic flux distribution in ''core'' metabolic pathways mainly supporting cell growth and maintenance. Finally, the model prediction in elucidating and reprogramming the native fermentative metabolism of E. coli for obligate anaerobic production of n-butanol and isobutanol was validated with published experimental data. (orig.)

  11. Subdiffraction instrumentation development and application to the elucidation of biological systems, thin films, and organic photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Lesoine, Michael D [Iowa State Univ., Ames, IA (United States)

    2014-12-01

    Fluorescence and Raman instrumentation was developed to elucidate morphology, information on local environment, and material properties of target systems. Far-field fluorescence and luminescence spectroscopic measurements were performed using a pulsed super-continuum laser source and detector with high temporal resolution. With this arrangement morphologies of structures were coupled with time-correlated data. Polymeric beads and Alexa Fluor 594-phalloidin labeled cellular actin structures of cultured cells were imaged below the diffraction limit using stimulated emission depletion to resolve structures to ≈40nm. Lifetime imaging revealed a 2.0 ± 0.1 ns lifetime for fluorescently-labeled beads in confocal and depletion imaging modes. Depletion imaging was also able to display a change of 2.2 to 2.9 ns for different regions of the cellular actin network of cultured cells with a possible difference in lifetime caused by tryptophan quenching of the dye. Subdiffraction imaging with a resolution of ≈40 nm was also accomplished using luminescence depletion of photostable giant CdSe/14CdS nanocrystal quantum dots in air. Nanocrystal quantum dots, typically not prone to depletion, exhibited this phenomenon when excited with an energy of 50 pJ and 2 nJ of depletion energy. Luminescence depletion required half the energy compared to stimulated emission depletion to achieve the same resolution limit. The luminescence was depleted by as much as ≈92% with no observable photobleaching. Raman measurements of polymer films were performed with 532-nm laser illumination using scanning angle and conventional 180° backscattering modes to determine chemical information. The scanning angle mode achieved an angle resolution of 0.09° and was used to probe a thin layer of polystyrene as well as a diblock copolymer of polystyrene and poly(3-hexylthiophene-2,5-diyl). Enhancements to the Raman signals at selected angles lower than the critical angle for total internal reflection

  12. Structure and stoichiometry

    International Nuclear Information System (INIS)

    Gai, P.L.

    1992-01-01

    Structural and stoichiometric variations and their role in superconducting properties of bulk cuprate ceramics are elucidated. Atomic structure and chemistry of defect microstructures, including vacancy and interstitial defects, weak-link problems, structural modulations and coherent intergrowths leading to new structures are studies and quantitatively interpreted. They are shown to play a critical role in controlling hole concentration, critical currents and flux pinning. These phenomena underpin the solid state chemistry which determines the physical properties of the nonstoichiometric oxide superconductors. In this paper technological implications, synthesis of related novel materials and recent developments are discussed

  13. Elucidation of chemosensitization effect of acridones in cancer cell lines: Combined pharmacophore modeling, 3D QSAR, and molecular dynamics studies.

    Science.gov (United States)

    Gade, Deepak Reddy; Makkapati, Amareswararao; Yarlagadda, Rajesh Babu; Peters, Godefridus J; Sastry, B S; Rajendra Prasad, V V S

    2018-02-24

    Overexpression of P-glycoprotein (P-gp) leads to the emergence of multidrug resistance (MDR) in cancer treatment. Acridones have the potential to reverse MDR and sensitize cells. In the present study, we aimed to elucidate the chemosensitization potential of acridones by employing various molecular modelling techniques. Pharmacophore modeling was performed for the dataset of chemosensitizing acridones earlier proved for cytotoxic activity against MCF7 breast cancer cell line. Gaussian-based QSAR studies also performed to predict the favored and disfavored region of the acridone molecules. Molecular dynamics simulations were performed for compound 10 and human P-glycoprotein (obtained from Homology modeling). An efficient pharmacophore containing 2 hydrogen bond acceptors and 3 aromatic rings (AARRR.14) was identified. NCI 2012 chemical database was screened against AARRR.14 CPH and identified 25 best-fit molecules. Potential regions of the compound were identified through Field (Gaussian) based QSAR. Regression analysis of atom-based QSAR resulted in r 2 of 0.95 and q 2 of 0.72, whereas, regression analysis of field-based QSAR resulted in r 2 of 0.92 and q 2 of 0.87 along with r 2 cv as 0.71. The fate of the acridone molecule (compound 10) in the P-glycoprotein environment is analyzed through analyzing the conformational changes occurring during the molecular dynamics simulations. Combined data of different in silico techniques provided basis for deeper understanding of structural and mechanistic insights of interaction phenomenon of acridones with P-glycoprotein and also as strategic basis for designing more potent molecules for anti-cancer and multidrug resistance reversal activities. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Cognition, quality-of-life, and symptom clusters in breast cancer: Using Bayesian networks to elucidate complex relationships.

    Science.gov (United States)

    Xu, Selene; Thompson, Wesley; Ancoli-Israel, Sonia; Liu, Lianqi; Palmer, Barton; Natarajan, Loki

    2018-03-01

    Breast cancer patients frequently complain of cognitive dysfunction during chemotherapy. Patients also report experiencing a cluster of sleep problems, fatigue, and depressive symptoms during chemotherapy. We aimed to understand the complex dynamic interrelationships of depression, fatigue, and sleep to ultimately elucidate their role in cognitive performance and quality of life amongst breast cancer survivors undergoing chemotherapy treatment. Our study sample comprised 74 newly diagnosed stage I to III breast cancer patients scheduled to receive chemotherapy. An objective neuropsychological test battery and self-reported fatigue, mood, sleep quality, and quality of life were collected at 3 time points: before the start of chemotherapy (baseline: BL), at the end of cycle 4 chemotherapy (C4), and 1 year after the start of chemotherapy (Y1). We applied novel Bayesian network methods to investigate the role of sleep/fatigue/mood on cognition and quality of life prior to, during, and after chemotherapy. The fitted network exhibited strong direct and indirect links between symptoms, cognitive performance, and quality of life. The only symptom directly linked to cognitive performance was C4 sleep quality; at C4, fatigue was directly linked to sleep and thus indirectly influenced cognitive performance. Mood strongly influenced concurrent quality of life at C4 and Y1. Regression estimates indicated that worse sleep quality, fatigue, and mood were negatively associated with cognitive performance or quality of life. The Bayesian network identified local structure (eg, fatigue-mood-QoL or sleep-cognition) and possible intervention targets (eg, a sleep intervention to reduce cognitive complaints during chemotherapy). Copyright © 2017 John Wiley & Sons, Ltd.

  15. A Metaproteomics Approach to Elucidate Host and Pathogen Protein Expression during Catheter-Associated Urinary Tract Infections (CAUTIs)

    Science.gov (United States)

    Lassek, Christian; Burghartz, Melanie; Chaves-Moreno, Diego; Otto, Andreas; Hentschker, Christian; Fuchs, Stephan; Bernhardt, Jörg; Jauregui, Ruy; Neubauer, Rüdiger; Becher, Dörte; Pieper, Dietmar H.; Jahn, Martina; Jahn, Dieter; Riedel, Katharina

    2015-01-01

    Long-term catheterization inevitably leads to a catheter-associated bacteriuria caused by multispecies bacterial biofilms growing on and in the catheters. The overall goal of the presented study was (1) to unravel bacterial community structure and function of such a uropathogenic biofilm and (2) to elucidate the interplay between bacterial virulence and the human immune system within the urine. To this end, a metaproteomics approach combined with in vitro proteomics analyses was employed to investigate both, the pro- and eukaryotic protein inventory. Our proteome analyses demonstrated that the biofilm of the investigated catheter is dominated by three bacterial species, that is, Pseudomonas aeruginosa, Morganella morganii, and Bacteroides sp., and identified iron limitation as one of the major challenges in the bladder environment. In vitro proteome analysis of P. aeruginosa and M. morganii isolated from the biofilm revealed that these opportunistic pathogens are able to overcome iron restriction via the production of siderophores and high expression of corresponding receptors. Notably, a comparison of in vivo and in vitro protein profiles of P. aeruginosa and M. morganii also indicated that the bacteria employ different strategies to adapt to the urinary tract. Although P. aeruginosa seems to express secreted and surface-exposed proteases to escape the human innate immune system and metabolizes amino acids, M. morganii is able to take up sugars and to degrade urea. Most interestingly, a comparison of urine protein profiles of three long-term catheterized patients and three healthy control persons demonstrated the elevated level of proteins associated with neutrophils, macrophages, and the complement system in the patient's urine, which might point to a specific activation of the innate immune system in response to biofilm-associated urinary tract infections. We thus hypothesize that the often asymptomatic nature of catheter-associated urinary tract infections

  16. Pulsatile secretion of thyrotropin during fasting: a decrease of thyrotropin pulse amplitude

    NARCIS (Netherlands)

    Romijn, J. A.; Adriaanse, R.; Brabant, G.; Prank, K.; Endert, E.; Wiersinga, W. M.

    1990-01-01

    The effect of fasting on circadian and pulsatile TSH secretion was investigated in eight healthy subjects (four men and four women in the follicular phase). Each subject was studied twice, once during 24 h with normal food intake and once during the last 24 h of a 60-h fast. Blood was sampled every

  17. Multiple thyrotropin β-subunit and thyrotropin receptor-related genes arose during vertebrate evolution.

    Directory of Open Access Journals (Sweden)

    Gersende Maugars

    Full Text Available Thyroid-stimulating hormone (TSH is composed of a specific β subunit and an α subunit that is shared with the two pituitary gonadotropins. The three β subunits derive from a common ancestral gene through two genome duplications (1R and 2R that took place before the radiation of vertebrates. Analysis of genomic data from phylogenetically relevant species allowed us to identify an additional Tshβ subunit-related gene that was generated through 2R. This gene, named Tshβ2, present in cartilaginous fish, little skate and elephant shark, and in early lobe-finned fish, coelacanth and lungfish, was lost in ray-finned fish and tetrapods. The absence of a second type of TSH receptor (Tshr gene in these species suggests that both TSHs act through the same receptor. A novel Tshβ sister gene, named Tshβ3, was generated through the third genomic duplication (3R that occurred early in the teleost lineage. Tshβ3 is present in most teleost groups but was lostin tedraodontiforms. The 3R also generated a second Tshr, named Tshrb. Interestingly, the new Tshrb was translocated from its original chromosomic position after the emergence of eels and was then maintained in its new position. Tshrb was lost in tetraodontiforms and in ostariophysians including zebrafish although the latter species have two TSHs, suggesting that TSHRb may be dispensable. The tissue distribution of duplicated Tshβs and Tshrs was studied in the European eel. The endocrine thyrotropic function in the eel would be essentially mediated by the classical Tshβ and Tshra, which are mainly expressed in the pituitary and thyroid, respectively. Tshβ3 and Tshrb showed a similar distribution pattern in the brain, pituitary, ovary and adipose tissue, suggesting a possible paracrine/autocrine mode of action in these non-thyroidal tissues. Further studies will be needed to determine the binding specificity of the two receptors and how these two TSH systems are interrelated.

  18. Using spatial capture–recapture to elucidate population processes and space-use in herpetological studies

    Science.gov (United States)

    Muñoz, David J.; Miller, David A.W.; Sutherland, Chris; Grant, Evan H. Campbell

    2016-01-01

    The cryptic behavior and ecology of herpetofauna make estimating the impacts of environmental change on demography difficult; yet, the ability to measure demographic relationships is essential for elucidating mechanisms leading to the population declines reported for herpetofauna worldwide. Recently developed spatial capture–recapture (SCR) methods are well suited to standard herpetofauna monitoring approaches. Individually identifying animals and their locations allows accurate estimates of population densities and survival. Spatial capture–recapture methods also allow estimation of parameters describing space-use and movement, which generally are expensive or difficult to obtain using other methods. In this paper, we discuss the basic components of SCR models, the available software for conducting analyses, and the experimental designs based on common herpetological survey methods. We then apply SCR models to Red-backed Salamander (Plethodon cinereus), to determine differences in density, survival, dispersal, and space-use between adult male and female salamanders. By highlighting the capabilities of SCR, and its advantages compared to traditional methods, we hope to give herpetologists the resource they need to apply SCR in their own systems.

  19. Multi-omics approach to elucidate the gut microbiota activity. Metaproteomics and metagenomics connection.

    Science.gov (United States)

    Guirro, Maria; Costa, Andrea; Gual-Grau, Andreu; Mayneris-Perxachs, Jordi; Torrell, Helena; Herrero, Pol; Canela, Núria; Arola, Lluís

    2018-02-10

    Over the last few years, the application of high-throughput meta-omics methods has provided great progress in improving the knowledge of the gut ecosystem and linking its biodiversity to host health conditions, offering complementary support to classical microbiology. Gut microbiota plays a crucial role in relevant diseases such as obesity or cardiovascular disease, and its regulation be closely influenced by several factors, such as dietary composition. In fact, polyphenol-rich diets are the most palatable treatment to prevent hypertension associated with cardiovascular disease, although the polyphenol-microbiota interactions have not been completely elucidated. For this reason, the aim of this study was to evaluate microbiota effect in obese rats supplemented by, after being fed with cafeteria or standard diet, using a multi meta-omics approaches combining strategy of metagenomics and metaproteomics analysis. We reported that cafeteria diet induces obesity, resulting in changes in the microbiota composition, which are related to functional alterations at proteome level. In addition, hesperidin supplementation alters microbiota diversity and also proteins involved in important metabolic pathways. Overall, going deeper into strategies to integrate omics sciences is necessary to understand the complex relationships between the host, gut microbiota and diet. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Modeling Rice Metabolism: From Elucidating Environmental Effects on Cellular Phenotype to Guiding Crop Improvement.

    Science.gov (United States)

    Lakshmanan, Meiyappan; Cheung, C Y Maurice; Mohanty, Bijayalaxmi; Lee, Dong-Yup

    2016-01-01

    Crop productivity is severely limited by various biotic and abiotic stresses. Thus, it is highly needed to understand the underlying mechanisms of environmental stress response and tolerance in plants, which could be addressed by systems biology approach. To this end, high-throughput omics profiling and in silico modeling can be considered to explore the environmental effects on phenotypic states and metabolic behaviors of rice crops at the systems level. Especially, the advent of constraint-based metabolic reconstruction and analysis paves a way to characterize the plant cellular physiology under various stresses by combining the mathematical network models with multi-omics data. Rice metabolic networks have been reconstructed since 2013 and currently six such networks are available, where five are at genome-scale. Since their publication, these models have been utilized to systematically elucidate the rice abiotic stress responses and identify agronomic traits for crop improvement. In this review, we summarize the current status of the existing rice metabolic networks and models with their applications. Furthermore, we also highlight future directions of rice modeling studies, particularly stressing how these models can be used to contextualize the affluent multi-omics data that are readily available in the public domain. Overall, we envisage a number of studies in the future, exploiting the available metabolic models to enhance the yield and quality of rice and other food crops.