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Glycine
Terms modified by Glycine Selected AbstractsSwitching of the transmitters that mediate hindbrain correlated activity in the chick embryoEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009Hiraku Mochida Abstract Widely propagating correlated neuronal activity is a hallmark of the developing nervous system. The activity is usually mediated by multiple transmitters, and the contribution of gap junctions has also been suggested in several systems. In some structures, such as the retina and spinal cord, it has been shown that the dominant transmitter mediating the correlated wave switches from acetylcholine to glutamate during development, although the functional significance of this phenomenon has not been clarified. An important question is whether such a transmitter switch occurs in other systems, especially in the brain. In the present study, we demonstrate that the major transmitter mediating correlated wave activity in the embryonic chick hindbrain changes from acetylcholine/,-aminobutyric acid (GABA)/glycine to glutamate/GABA as development proceeds. The results show for the first time that the dominant transmitter switches from acetylcholine to glutamate in a region other than the retina and spinal cord. This finding sheds more light on the role of nicotinic acetylcholine receptors in the generation of correlated wave activity, which is considered to regulate the development of the nervous system. [source] Preparation and characterization of biodegradable waterabsorbent PAN/SS nanocompositePOLYMER COMPOSITES, Issue 11 2008Bijayashree Samal Polyacrylonitrile (PAN)/sodium silicate (SS) nanocomposite was prepared via nonconventional emulsion method using an in situ developed transition metal complex Cu(II)/glycine taking ammonium persulfate (APS) as initiator, with a novel motive of converting hydrophobic homopolymer PAN into hydrophilic nano material via nanotechnology by the inclusion of SS to the homopolymer. UV,visible spectral analysis was carried out which revealed various interactions between the in situ developed complex with other reaction components. The formation of the PAN/SS nanocomposite was confirmed by infrared spectra (IR). Furthermore, as evidenced by transmission electron microscopy (TEM), the composite so obtained was found to have nano scale structure. X-ray diffraction (XRD) was carried out suggesting that the silicate layers were exfoliated during the polymerization process. An increase in the thermal stability for the developed nanocomposite was recorded by thermogravimetric analysis (TGA). Surprisingly, it was also found that the PAN/SS nanocomposite showed considerable amount of waterabsorbency and was biodegradable as tested by activated sludge and cultured media and further confirmed by scanning electron microscopy (SEM). POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] XRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007E. Ramachandran Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] GABA and glycine are protective to mature but toxic to immature rat cortical neurons under hypoxiaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2005Peng Zhao Abstract Although recent studies suggest that ,-aminobutyric acid (GABA) and glycine may be ,inhibitory' to mature neurons, but ,excitatory' to immature neurons under normoxia, it is unknown whether inhibitory neurotransmitters are differentially involved in neuronal response to hypoxia in immature and mature neurons. In the present study, we exposed rat cortical neurons to hypoxia (1% O2) and examined the effects of three major inhibitory neurotransmitters (GABA, glycine and taurine) on the hypoxic neurons at different neuronal ages [days in vitro (DIV)4,20]. Our data showed that the cortical neurons expressed both GABAA and glycine receptors with differential developmental profiles. GABA (10,2000 µm) was neuroprotective to hypoxic neurons of DIV20, but enhanced hypoxic injury in neurons of <,DIV20. Glycine at low concentrations (10,100 µm) exhibited a similar pattern to GABA. However, higher concentrations of glycine (1000,2000 µm) for long-term exposure (48,72 h) displayed neuroprotection at all ages (DIV4,20). Taurine (10,2000 µm), unlike GABA and glycine, displayed protection only in DIV4 neurons, and was slightly toxic to neurons >,DIV4. In comparison with delta-opioid receptor (DOR)-induced protection in DIV20 neurons exposed to 72 h of hypoxia, glycine-induced protection was weaker than that of DOR but stronger than that of GABA and taurine. These data suggest that the effects of the inhibitory neurotransmitters on hypoxic cortical neurons are age-dependent, with GABA and glycine being neurotoxic to immature neurons and neuroprotective to mature neurons. [source] Conduction block and glial injury induced in developing central white matter by glycine, GABA, noradrenalin, or nicotine, studied in isolated neonatal rat optic nerveGLIA, Issue 11 2009Stavros Constantinou Abstract The damaging effects of excessive glutamate receptor activation have been highlighted recently during injury in developing central white matter. We have examined the effects of acute exposure to four other neurotransmitters that have known actions on white matter. Eighty minutes of Glycine or GABA-A receptor activation produced a significant fall in the compound action potential recorded from isolated post-natal day 10 rat optic nerve. This effect was largely reversed upon washout. Nicotinic acetylcholine receptor (nAChR) or adrenoreceptor activation with noradrenalin resulted in an ,35% block of the action potential that did not reverse during a 30-min washout period. While the effect of nAChR activation was blocked by a nAChR antagonist, the effect of noradrenalin was not ablated by ,- or ,-adrenoreceptor blockers applied alone or in combination. In the absence of noradrenalin, co-perfusion with ,- and ,-adrenoreceptor blockers resulted in nonreversible nerve failure indicating that tonic adrenoreceptor activation is required for nerve viability, while overactivation of these receptors is also damaging. Nerves exposed to nAChR + adrenoreceptor activation showed no axon pathology but had extensive glial injury revealed by ultrastructural analysis. Oligodendroglia exhibited regions of membrane vacuolization while profound changes were evident in astrocytes and included the presence of swollen and expanded mitochondria, vacuolization, cell processes disintegration, and membrane breakdown. Blinded assessment revealed higher levels of astrocyte injury than oligodendroglial injury. The findings show that overactivation of neurotransmitter receptors other than those for glutamate can produce extensive injury to developing white matter, a phenomenon that may be clinically significant. © 2009 Wiley-Liss, Inc. [source] Sensory aroma from Maillard reaction of individual and combinations of amino acids with glucose in acidic conditionsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2008Kam Huey Wong Summary The aroma produced in glucose,amino acids (individual and in combination) Maillard reaction, under acidic conditions at 100 °C were determined and compared by trained panellist. Proline produced pleasant, flowery and fragrant aroma. Phenylalanine and tyrosine produced dried roses aroma. Alanine produced fruity and flowery odour, while aspartic acid and serine both produced pleasant, fruity aroma. Arginine, produced a pleasant, fruity and sour aroma at pH 5.2, but not at its natural pH. Glycine, lysine, threonine and valine produced a pleasant caramel-like odour. Isoleucine and leucine gave off a burnt caramel aroma. Methionine developed a fried potato odour. Cysteine and methionine produced savoury, meaty and soy sauce-like flavours. A combination of these amino acids produced different types of aroma, with the stronger note dominating the odour of the mixture. This study will help the prediction of flavour characteristics of hydrolysates from different protein sources. [source] Sources and Mechanisms of Carbon Monoxide Production by IrradiationJOURNAL OF FOOD SCIENCE, Issue 6 2004E.J. Lee ABSTRACT: The sources and mechanisms of gas production by irradiation were determined using model systems prepared with fatty acid, phospholipids, oil, sugars, glycolysis and TCA cycle intermediates, nucleic acids, amino acid monomers and homopolymers, and proteins. The model systems were irradiated at 0, 2.5, 5, or 10 kGy using a linear accelerator and the amounts of CO, CO, and CH produced were determined using gas chromatography. The productions of CO, CO2, and CH4 in all samples were irradiation-dose dependent. Glycine, asparagine, and glutamine were the major sources of CO production among amino acids, and glyceraldehydes, pyruvate, and ,-ketoglutarate were the major sources of CO among glycolysis intermediates. Phosphatidyl choline, phosphatidyl ethanolamine, and lysophosphatidyl choline produced the greatest amounts of CO among the phospholipids. The major sources of CO2 production were pyruvate, threoine, and methionine, and those of CH4 were methionine and acetone. The amounts of CO produced from these sources were significant, and the production of gas compounds via radiolytic degradation appears to be closely related to the structure of molecules. [source] Solute crystallization in mannitol,glycine systems,implications on protein stabilization in freeze-dried formulationsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2003Abira Pyne Abstract The use of mannitol in combination with glycine has resulted in stable freeze-dried protein formulations. Our objectives were to (1) study solute crystallization in ternary systems containing mannitol, glycine, and water during all the stages of freeze drying as a function of processing conditions and formulation variables; (2) investigate the effect of sodium phosphate buffer salts on the crystallization of both mannitol and glycine and vice versa; and (3) investigate the effects of these excipients in a freeze-dried lactate dehydrogenase (LDH) formulation. X-ray powder diffractometry (XRD) and differential scanning calorimetry (DSC) were used to study the frozen aqueous solutions. Phase transitions during primary and secondary drying were monitored by simulating the entire freeze-drying process in situ in the sample chamber of the diffractometer. LDH activity after freeze drying was determined spectrophotometrically. In frozen aqueous solutions containing mannitol and glycine, each solute influenced the extent of crystallization of the other. The solutes crystallized as ,-mannitol and ,-glycine during primary drying. Glycine had a stronger tendency to crystallize, while it was easier to influence mannitol crystallization. The buffer salts inhibited the crystallization of mannitol and glycine. However, in some cases, during primary drying, glycine crystallization was followed by that of disodium hydrogen phosphate dodecahydrate. The latter underwent dehydration forming an amorphous anhydrate. It was possible to correlate the extent of crystallization of mannitol and glycine in the lyophile with the retention of protein activity. An increase in buffer concentration decreased the crystallinity of mannitol and glycine. This translated to increased retention of protein activity. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2272,2283, 2003 [source] Glycine Receptors Contribute to Hypnosis Induced by EthanolALCOHOLISM, Issue 6 2009Jiang H. Ye Background:, Glycine is a major inhibitory neurotransmitter in the adult central nervous system (CNS), and its receptors (GlyRs) are well known for their effects in the spinal cord and the lower brainstem. Accumulating evidence indicates that GlyRs are more widely distributed in the CNS, including many supraspinal regions. Previous in vitro studies have demonstrated that ethanol potentiates the function of these brain GlyRs, yet the behavioral role of the brain GlyRs has not been well explored. Methods:, Experiments were conducted in rats. The loss of righting reflex (LORR) was used as a marker of the hypnotic state. We compared the LORR induced by systematic administration of ethanol and of ketamine in the absence and presence of the selective glycine receptor antagonist strychnine. Ketamine is a general anesthetic that does not affect GlyRs. Results:, Systemically administered (by intraperitoneal injection) ethanol and ketamine dose-dependently induced LORR in rats. Furthermore, systemically administered (by subcutaneous injection) strychnine dose-dependently reduced the percentage of rats exhibiting LORR induced by ethanol, increased the onset time, and decreased the duration of LORR. Strychnine had no effect, however, on the LORR induced by ketamine. Conclusions:, Given that hypnosis is caused by neuronal depression in upper brain areas, we therefore conclude that brain GlyRs contribute at least in part to the hypnosis induced by ethanol. [source] Differential Increase in Taurine Levels by Low-Dose Ethanol in the Dorsal and Ventral Striatum Revealed by Microdialysis With On-Line Capillary ElectrophoresisALCOHOLISM, Issue 7 2004A Smith Ethanol increases taurine efflux in the nucleus accumbens or ventral striatum (VS), a dopaminergic terminal region involved in positive reinforcement. However, this has been found only at ethanol doses above 1 g/kg intraperitoneally, which is higher than what most rats will self-administer. We used a sensitive on-line assay of microdialysate content to test whether lower doses of ethanol selectively increase taurine efflux in VS as opposed to other dopaminergic regions not involved in reinforcement (e.g., dorsal striatum; DS). Adult male rats with microdialysis probes in VS or DS were injected with ethanol (0, 0.5, 1, and 2 g/kg intraperitoneally), and the amino acid content of the dialysate was measured every 11 sec using capillary electrophoresis and laser-induced fluorescence detection. In VS, 0.5 g/kg ethanol significantly increased taurine levels by 20% for 10 min. A similar increase was seen after 1 g/kg ethanol, which lasted for about 20 min after injection. A two-phased taurine efflux was observed with the 2.0 g/kg dose, where taurine was increased by 2-fold after 5 min but it remained elevated by 30% for at least 60 min. In contrast, DS exhibited much smaller dose-related increases in taurine. Glycine, glutamate, serine, and ,-aminobutyric acid were not systematically affected by lower doses of ethanol; however, 2 g/kg slowly decreased these amino acids in both brain regions during the hour after injection. These data implicate a possible role of taurine in the mechanism of action of ethanol in the VS. The high sensitivity and time resolution afforded by capillary electrophoresis and laser-induced fluorescence detection will be useful for detecting subtle changes of neuronally active amino acids levels due to low doses of ethanol. [source] Emission of Pollutants from Glycine,Nitrate Combustion Synthesis ProcessesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2007Thomas Pine Four ceramic powders were produced using the glycine,nitrate process: lanthanum-doped barium cobaltite, ceria, magnesia, and strontium-doped lanthanum chromite (LSC). Glycine-to-nitrate ratios from 0.25 to 1 were investigated. During the combustion synthesis process, careful collection of process off-gas was followed by detailed gas analyses to determine product gas composition. All of the synthesis processes produced pure phase ceramic powders, but also produced criteria pollutant emissions levels that were significant enough (up to 4500 ppm of NOx and 9000 ppm of carbon monoxide) to warrant consideration. Equilibrium and chemical kinetic computations are used to determine the implications of the current findings. [source] Expression Of O-Acetyl Sialic Acid On Cerebral Microcirculation In A Glycine Or Taurine Treated Diabetic Rat ModelJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2000A Noe Expression of sialic acid is altered in Diabetes mellitus. This modification has also been involved with both vascular and neurologic diseases, and with the increase of no enzymatic glycosylation of proteins. In our opinion, the lectins were very useful with specificity for sialic acids in order to determine the level of sialic acid expression on cerebral microcirculation in a diabetic Wistar rat model with streptozotocin. In this model, the glycine (1%) and taurine (0.5%) aminoacids were placed in drinking-water by six months. At the end of this time, the animals were sacrificed, their brains surgically removed and frozen in liquid nitrogen, and the specimens cut in serial sections. Immediately, the sections were incubated with different biotin-labelled lectins specific to sialic acid using peroxidase-labelled avidin as second ligand and H2O2 chromogen. The results showed greater O-acetyl sialic acid expression in cerebral capillaries of untreated diabetic rats than in glycine-, taurine-treated diabetic rats or than in control animals. The minor sialic acid expression may be an indicator of degenerative diseases such as Alzheimer's or the vascular disease of diabetic patients and probably is related to cellular protective properties of the glycine and taurine aminoacids. These first protective characteristics that have been observed in both ischemia with cellular ATP depletion models, suggest the utilization of aminoacids glycine or taurine in diabetic patient in order to avoid the development of microinfarcts. [source] Glycinergic input of widefield, displaced amacrine cells of the mouse retinaTHE JOURNAL OF PHYSIOLOGY, Issue 15 2009Sriparna Majumdar Glycine receptors (GlyRs) of displaced amacrine cells of the mouse retina were analysed using whole cell recordings and immunocytochemical staining with subunit-specific antibodies. During the recordings the cells were filled with a fluorescent tracer and 11 different morphological types could be identified. The studies were performed in wild-type mice and in mutant mice deficient in the GlyR,1 (Glra1spd-ot, ,oscillator' mouse), the GlyR,2 (Glra2,/,) and the GlyR,3 subunit (Glra3,/,). Based on their responses to the application of exogenous glycine in the retinas of wild-type and mutant mice, the cells were grouped into three major classes: group I cells (comprising the morphological types MA-S5, MA-S1, MA-S1/S5, A17, PA-S1, PA-S5 and WA-S1), group II cells (comprising the morphological types PA-S4, WA-S3 and WA-multi) and ON-starburst cells. For further analysis, spontaneous inhibitory postsynaptic currents (sIPSCs) were measured both in wild-type and mutant mouse retinas. Glycinergic sIPSCs and glycine induced currents of group I cells remained unaltered across wild-type and the three mutant mice (mean decay time constant of sIPSCs, ,,25 ms). Group II cells showed glycinergic sIPSCs and glycine induced currents in wild-type, Glra1spd-ot and Glra3,/, mice (,,25 ms); however, glycinergic currents were absent in group II cells of Glra2,/, mice. Glycine induced currents and sIPSCs recorded from ON-starburst amacrine cells did not differ significantly between wild-type and the mutant mouse retinas (,,50,70 ms). We propose that GlyRs of group II cells are dominated by the ,2 subunit; GlyRs of ON-starburst amacrine cells appear to be dominated by the ,4 subunit. [source] ,-Glycine- O:O,-di-,-oxo-bis[(glycinato- N,O)oxomolybdenum(V)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2000Guang Liu In the title compound, [Mo2O4(C2H4NO2)2(C2H5NO2)], two Mo atoms sit in the same distorted pentagonal bipyramid coordination environment. There are four ligand types: oxo-O, ,2 -O, ,2 -glycine and chelate glycine. There is an Mo,Mo bond between the two Mo atoms [2.552,(1),Ĺ]. All amino groups participate in hydrogen bonding with O atoms of other molecules, thus connecting the molecules into a three-dimensional structure. [source] New chromosome reports in the subtribes Diocleinae and Glycininae (Phaseoleae: Papilionoideae: Fabaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2008SHIRLEY M. ESPERT The base chromosome number of x = 11 is the most probable in all the subtribes included in tribe Phaseoleae, although some aneuploid reduction is evident in Collaea and Galactia (Diocleinae) and chromosome duplications are seen in Amphicarpaea, Cologania and Glycine (Glycininae). The aims of this study were to improve the cytological knowledge of some species of Collaea and Galactia and to examine the anomalous counts reported for Calopogonium (Glycininae) and verify its taxonomic position. In addition, a molecular phylogeny was constructed using nuclear ribosomal DNA sequences (internal transcribed spacer region), and the chromosome number was optimized on the topology. In this work, the chromosome counts for Galactia lindenii, Galactia decumbens and Collaea cipoensis (all 2n = 20), and Calopogonium sericeum (2n = 22) are reported for the first time. The new reports for Galactia and Collaea species are in agreement with the chromosome number proposed for subtribe Diocleinae. The study rejects the concept of a cytologically anomalous Calopogonium and, based on the phylogenetic analysis, corroborates the position of this genus within subtribe Glycininae. The ancestral basic chromosome number of x = 11 proposed for Phaseoleae is in agreement with the evolutionary pathway of chromosome numbers analysed in this work. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 336,341. [source] Distinguishing between type 2B and pseudo-von Willebrand disease and its clinical importanceBRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2006Mohammad S. Enayat Summary Pseudo-von Willebrand disease (p-VWD) and type 2B von Willebrand disease (VWD) have similar phenotypic parameters and clinical symptoms, but different aetiologies. Fourteen individuals from five families with a historical diagnosis of type 2B VWD but with no mutation in the von Willebrand factor gene were re-investigated for the possibility of p-VWD, using platelet aggregation in the presence of cryoprecipitate. p-VWD was confirmed by targeted DNA sequencing of the glycoprotein Ib, gene, identifying a heterozygous Glycine 233 Valine substitution. This study suggests that p-VWD may be under diagnosed, and that platelet aggregation in the presence of cryoprecipitate is useful in differentiating this disorder from type 2B VWD. [source] New Synthesis and Fungicidal Activity of a Phosphinic Analogue of Glycine.CHEMINFORM, Issue 43 2004Yurii N. Zhukov Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: A Photochemical Approach to Phenylalanines and Related Compounds by Alkylation of Glycine.CHEMINFORM, Issue 2 2002Haydn S. Knowles Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Infrared Multiple-Photon Dissociation Mechanisms of Peptides of GlycineCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2008Ronghu Wu Dr. Peptide patterns: The current experimental results indicate that infrared multiple-photon dissociation (IRMPD) of peptides forms more structurally informative sequence b and y ions, and fewer less useful nonsequence ions. Also the dissociation pathways are the same through excitation of different modes of the peptide. For the first time, it has been confirmed that the peptide dissociation pathway is not related to the initial protonation site or the conformation (e.g., cyclic or linear, see graphic) of the peptide. [source] An Experimental and Theoretical Investigation of Gas-Phase Reactions of Ca2+ with GlycineCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2006Inés Corral Dr. Abstract The gas-phase reactions between Ca2+ and glycine ([Ca(gly)]2+) have been investigated through the use of mass spectrometry techniques and B3-LYP/cc-pWCVTZ density functional theory computations. The major peaks observed in the electrospray MS/MS spectrum of [Ca(gly)]2+ correspond to the formation of the [Ca,C,O2,H]+, NH2CH2+, CaOH+, and NH2CH2CO+ fragment ions, which are produced in Coulomb explosion processes. The computed potential energy surface (PES) shows that not only are these species the most stable product ions from a thermodynamic point of view, but they may be produced with barriers lower than for competing processes. Carbon monoxide is a secondary product, derived from the unimolecular decomposition of some of the primary ions formed in the Coulomb explosions. In contrast to what is found for the reactions of Ca2+ with urea ([Ca(urea)]2+), minimal unimolecular losses of neutral fragments are observed for the gas-phase fragmentation processes of [Ca(gly)]2+, which is readily explained in terms of the topological differences between their respective PESs. [source] Metal Aminocarboxylate Coordination Polymers with Chain and Layered StructuresCHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2005Meenakshi Dan Abstract The synthesis and structures of metal aminocarboxylates prepared in acidic, neutral, or alkaline media have been explored with the purpose of isolating coordination polymers with linear chain and two-dimensional layered structures. Metal glycinates of the formulae [CoCl2(H2O)2(CO2CH2NH3)] (I), [MnCl2(CO2CH2NH3)2] (II), and [Cd3Cl6(CO2CH2NH3)4] (III) with one-dimensional chain structures have been obtained by the reaction of the metal salts with glycine in an acidic medium under hydro/solvothermal conditions. These chain compounds contain glycine in the zwitterionic form. 4-Aminobutyric acid transforms to a cyclic amide under such reaction conditions, and the amide forms a chain compound of the formula [CdBr2(C4H7NO)2] (IV). Glycine in the zwitterionic form also forms a two-dimensional layered compound of the formula [Mn(H2O)2(CO2CH2NH3)2]Br2 (V). 6-Aminocaproic acid under alkaline conditions forms layered compounds with metals at room temperature, the metal being coordinated both by the amino nitrogen and the carboxyl oxygen atoms. Of the two layered compounds [Cd{CO2(CH2)5NH2}2],2,H2O (VI) and [Cu{CO2(CH2)5NH2}2],2,H2O (VII), the latter has voids in which water molecules reside. [source] Theoretical and Experimental Study of the Adsorption of Neutral Glycine on Silica from the Gas PhaseCHEMPHYSCHEM, Issue 6 2005C. Lomenech Dr. Abstract The adsorption of neutral glycine onto amorphous silica was investigated both theoretically and experimentally. DFT calculations were performed at the BLYP-631++G** level using a cluster approach. Several possible configurations involving the formation of H bonds between glycine and one, two, or three silanol groups (SiOH) were considered. The most favorable bonding of glycine with one silanol group (45 kJ,mol,1) occurs through the COOH moiety, thus forming a cycle in which the CO group is an H-bond acceptor whereas the acidic OH group is an H-bond donor. With two or three silanol groups, additional H bonds are formed between the amine moiety and the silanol groups, which leads to an increased adsorption energy (70 and 80 kJ,mol,1for two and three silanol groups, respectively). Calculated ,CO, ,HNH, and ,HCHvalues are sensitive to the adsorption mode. A bathochromic shift of ,COas compared to the ,COof free glycine (calculated in the 1755,1790 cm,1range) is found for glycine in interaction with silanol(s). The more H bonds are formed between the COOH moiety and silanol groups, the higher the bathochromic shift. For ,HNH, no shift is found for glycine adsorbed on one and two silanol groups (where the amine is either not bound or an H-bond donor), whereas a bathochromic shift is calculated with three silanols when the amine moiety is an H-bond acceptor. Experimental FTIR spectra performed at room temperature for glycine adsorbed at 160,°C on Aerosil amorphous silica exhibit bands at 1371, 1423, 1630, and 1699 cm,1. The experimental/calculated frequencies have their best correspondence for glycine adsorbed on two silanol groups. It is important to note that the forms giving the best correspondence to experimental frequencies are the most stable ones. [source] Sudden infant death syndrome (SIDS) in African Americans: polymorphisms in the gene encoding the stress peptide pituitary adenylate cyclase-activating polypeptide (PACAP)ACTA PAEDIATRICA, Issue 3 2009Kevin J Cummings Abstract Aims: Mice lacking pituitary adenylate cyclase-activating polypeptide (PACAP) are prone to sudden death in the second post-natal week, having respiratory and metabolic disturbances reminiscent of the human Sudden Infant Death Syndrome (SIDS). Here we test the hypothesis that the human PACAP gene is a site of genetic variance associated with SIDS in a cohort of 92 victims and 92 matched controls. Methods: Using polymerase chain reaction and sequencing, we examined the PACAP gene in 92 SIDS cases (46 Caucasians and 46 African Americans) and 92 race- and gender-matched controls. Results: We found no significant associations between PACAP and SIDS in Caucasians. However, in the African Americans, a non-synonymous single nucleotide polymorphism (i.e. an aspartic acid/glycine coding variant, rs2856966) within exon 2 of PACAP was significantly associated with SIDS (p = 0.004), as were haplotypes containing this polymorphism (p < 0.0001). Glycine was three times more likely at this location in the African-American SIDS victims (17 cases) than African-American controls (5 cases). Conclusion: These data are the first to suggest an association between a variant within the coding region of the PACAP gene and SIDS. Based on these findings, further investigations are warranted into the functional importance of PACAP signaling in neonatal survival and the role of PACAP-signaling abnormalities in SIDS. [source] Synthesis and Conformational Analysis of Pentapeptides Containing Enantiomerically Pure 2,2-Disubstituted GlycinesHELVETICA CHIMICA ACTA, Issue 3 2008Kathrin Abstract The synthesis and conformational analysis of model pentapeptides with the sequence Z-Leu-Aib-Xaa-Gln-Valol is described. These peptides contain two 2,2-disubstituted glycines (,,, -disubstituted , -amino acids), i.e., Aib (aminoisobutyric acid), and a series of unsymmetrically substituted, enantiomerically pure amino acids Xaa. These disubstituted amino acids were incorporated into the model peptides via the ,azirine/oxazolone method'. Conformational analysis was performed in solution by means of NMR techniques and, in the solid state, by X-ray crystallography. Both methods show that the backbones of these model peptides adopt helical conformations, as expected for 2,2-disubstitued glycine-containing peptides. [source] Synthesis of New N-(5-Oxo-2,5-dihydro)pyrrol-3-yl Glycines and N-(5-Oxo-2,5-dihydro)pyrrol-3-yl Glycines EstersCHEMINFORM, Issue 5 2006Fabrice Jourdan Abstract For Abstract see ChemInform Abstract in Full Text. [source] The role of inhibitory neurotransmission in locomotor circuits of the developing mammalian spinal cordACTA PHYSIOLOGICA, Issue 2 2009H. Nishimaru Abstract Neuronal circuits generating the basic coordinated limb movements during walking of terrestrial mammals are localized in the spinal cord. In these neuronal circuits, called central pattern generators (CPGs), inhibitory synaptic transmission plays a crucial part. Inhibitory synaptic transmission mediated by glycine and GABA is thought to be essential in coordinated activation of muscles during locomotion, in particular, controlling temporal and spatial activation patterns of muscles of each joint of each limb on the left and right side of the body. Inhibition is involved in other aspects of locomotion such as control of speed and stability of the rhythm. However, the precise roles of neurotransmitters and their receptors mediating inhibitory synaptic transmission in mammalian spinal CPGs remain unclear. Moreover, many of the inhibitory interneurones essential for output pattern of the CPG are yet to be identified. In this review, recent advances on these issues, mainly from studies in the developing rodent spinal cord utilizing electrophysiology, molecular and genetic approaches are discussed. [source] Study of the MR relaxation of microglia cells labeled with Gd-DTPA-bearing nanoparticlesCONTRAST MEDIA & MOLECULAR IMAGING, Issue 3 2009Emeline Julie Ribot Abstract Therapies involving cells as vehicles need to visualize in situ the trafficking of the cells concerned. This cellular imaging can be driven by cell contrast agent-based nanoparticle internalization and non-invasive MRI (magnetic resonance imaging) detection. Here, microglial cells, that would transport a suicide gene to a glioma, were incubated for different times, with various concentrations of silica nanoparticles on which numerous Gd-DTPA were grafted. The goal of this study was to investigate the repartition of cell-associated particles. MRI was used to quantitatively follow the particle uptake process. Fluorescence microscopy images showed that, although most of the nanoparticles were internalized, some remained adsorbed on the extracellular membrane surface. The cells were then submitted to various treatments: glycine to release bound nanoparticles and/or ultrasound to destroy the cell membranes. The R1 relaxation rates were measured at 4.7 T. R1 was maximal for 4,h of incubation, decreased after 8,h and remained stable for the 24 following hours. The magnetic resonance signal of ultrasonicated and glycine-treated cells made it possible to quantify the loss of bound nanoparticles after 8,h. Nevertheless, this release did not prevent cell detection since the internalized nanoparticles are enough concentrated to visualize the labeled cells even after 4 days of cell growth. These results highlight the compartmentalization of nanoparticles in microglia and the evolution of the MR signal of the labeled cells. This study could be of importance to interpret in vivo the MR signal changes that could occur after administration of such nanoparticle-labeled cells in therapeutic strategies. Copyright © 2009 John Wiley & Sons, Ltd. [source] Molecular recognition of sugars by lanthanide (III) complexes of a conjugate of N, N -bis[2-[bis[2-(1, 1-dimethylethoxy)-2-oxoethyl]amino]ethyl]glycine and phenylboronic acidCONTRAST MEDIA & MOLECULAR IMAGING, Issue 4 2007Elisa Battistini Abstract A novel conjugate of phenylboronic acid and an Ln(DTPA) derivative, in which the central acetate pendant arm was replaced by the methylamide of L -lysine, was synthesized and characterized. The results of a fit of variable 17O NMR data and a 1H NMRD profile show that the water residence lifetime of the Gd(III) complex (150,ns) is shorter than that of the parent compound Gd(DTPA)2, (303,ns). Furthermore, the data suggest that several water molecules in the second coordination sphere of Gd(III) contribute to the relaxivity of the conjugate. The Ln(III) complexes of this conjugate are highly suitable for molecular recognition of sugars. The interaction with various sugars was investigated by 11B NMR spectroscopy. Thanks to the thiourea function that links the phenylboronic acid targeting vector with the DTPA derivative, the interactions are stronger than that of phenylboronic acid itself. In particular, the interaction with N -propylfructosamine, a model for the glucose residue in glycated human serum albumin (HSA), is very strong. Unfortunately, the complex also shows a rather strong interaction with hexose-free HSA (KA,=,705,±,300). Copyright © 2007 John Wiley & Sons, Ltd. [source] Crystal growth, crystal structure and physical properties of polar orthorhombic tris(glycine) zinc chlorideCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2008M. Fleck Abstract Large single crystals of the polar (point group mm 2) compound tris(glycine) zinc chloride, (NH3CH2COO)3 · ZnCl2, were grown from aqueous solutions. The refractive indices were measured in the wavelength region from 365 nm to 1083 nm and an unpolarised absorption spectrum was recorded (transparency range from 260 to 1550nm). The phase matching conditions for second harmonic generation were analysed: both, type I (ss-f) and type II (sf-f) are possible in the red and near IR region. All five components of the piezoelectric tensor [dijk ] were determined; the maximum values of longitudinal and transverse piezoelectric effects are less than one half of d111 of ,-quartz. In addition, a redetermination of the crystal structure (including location of H atoms) is presented. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] XRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007E. Ramachandran Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||||||||||||||||||||