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A comparative survey of the RF-amide peptide superfamily

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197309 Year: Pages: 160 DOI: 10.3389/978-2-88919-729-3 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General) --- Neurology --- Science (General)
Added to DOAB on : 2016-04-07 11:22:02
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Abstract

The discovery, twelve years ago, that the RF-amide peptide kisspeptin, acting via GPR54, is essential for the onset of puberty and reproduction, has been a major breakthrough in reproductive physiology. It has also put in front of the spotlights RF-amide peptides and allowed to revive research on this superfamily. The first member of this family to be characterized, in 1977, was the cardioexcitatory peptide, FMRFamide, isolated from the ganglia of the clam Macrocallista nimbosa. Since then, a large number of these peptides, designated after their C-terminal arginine (R) and amidated phenylalaline (F) residues, have been identified in representative species of all major phyla. By means of phylogenetic analyses, the superfamily of RFamide peptides has been divided into five families in vertebrates: kisspeptin, QFRP (including 26RFa), LPXRFa (including GnIH and RFRP), PQRFa (including NPFF) and PrRP. Recent data reveal that SIFamide-type neuropeptides in protostomian invertebrates and SALMFamide-type neuropeptides in deuterostomian invertebrates share a common evolutionary origin with vertebrate LPXRFa and PQRFa. Interestingly, in invertebrates as in vertebrates, multiple genes, as well as multiple mature peptides, are often present in a single species, questioning the need for such diversity in term of function. Comparative studies on non-mammalian vertebrates and invertebrates allow major advances in the knowledge of the evolutionary history of the RF-amide peptide superfamily. Such phylogenetical studies also contribute to improve classification and nomenclature of both peptides and receptors. RF-amide peptides from different families have major evolutionary conserved roles in the control of reproduction, but also of food intake, metabolism, energy expenditure, cardiovascular function, nociception and stress. They are also involved in the integration of environmental signals, notably the photoperiod, to regulate reproduction. For instance, in most vertebrate species and especially in seasonal mammals, kisspeptin and GnIH/RFRP have complementary but opposite effects in the control of reproductive function. In addition, recent data show cross-activities between the members of the RF-amide peptide superfamily and their receptors. For example, PrRP, kisspeptin and 26RFa are able to modulate nociception via NPFF receptors. Comparative studies have the potential to reveal novel regulatory mechanisms that could give a better comprehension of physiological functions and lead to new therapeutic treatments for related human pathologies. Thus, kisspeptin antagonists have been developed as novel tools for treatment of hormone-dependent disorders of reproduction such as precocious puberty and endometriosis or kisspeptin agonists for treatment of infertility, in humans. Studies on lower vertebrate models can also contribute to the discovery of new roles of these peptides, as seen recently with kisspeptin being involved in the early development of the medaka. This research topic will aim at gathering major advances achieved through comparative studies in (mammalian and non-mammalian) vertebrates and invertebrates, in the knowledge of RF-amide peptides in term of evolutionary history and physiological roles.

Keywords

RF-amide peptides --- GPCRs --- Kisspeptin --- GnIH --- PrRP --- NPFF --- QRFP --- evolution

Amide Bond Activation

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ISBN: 9783039212033 / 9783039212040 Year: Pages: 466 DOI: 10.3390/books978-3-03921-204-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-08-28 11:21:27
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The amide bond represents a privileged motif in chemistry. The recent years have witnessed an explosion of interest in the development of new chemical transformations of amides. These developments cover an impressive range of catalytic N–C bond activation in electrophilic, Lewis acid, radical, and nucleophilic reaction pathways, among other transformations. Equally relevant are structural and theoretical studies that provide the basis for chemoselective manipulation of amidic resonance. This monograph on amide bonds offers a broad survey of recent advances in activation of amides and addresses various approaches in the field.

Keywords

fumardiamide --- primaquine --- succindiamide --- Michael acceptor --- biofilm eradication --- antibacterial screening --- antiviral activity --- cytostatic activity --- N,N-dimethylformamide --- DMF --- N,N-dimethylacetamide --- DMAc --- amination --- amidation --- thioamidation --- formylation --- carbonylation --- cyanation --- insertion --- cyclization --- amide --- arynes --- insertion --- activation --- heterocycles --- organic synthesis --- multi-component coupling reaction --- aryl thioamides --- thiourea --- C-H/C-N activation --- C-S formation --- transition-metal-free --- rotational barrier energy --- amide bond --- nuclear magnetic resonance --- kinetic --- density functional theory --- non planar amide --- base-catalyed hydrolysis --- water solvation --- entropy --- transamidation --- amide --- amine --- catalyst --- catalysis --- acylative cross-coupling --- trialkylborane --- amide activation --- palladium --- N-heterocyclic carbene --- ruthenium (Ru) --- N-heterocyclic carbenes (NHCs) --- homogeneous catalysis --- in situ --- amide bonds --- synthesis --- density functional theory --- cis/trans isomerization --- secondary amides --- dipeptides --- steric effects --- tert-butyl --- additivity principle --- amino acid transporters --- amide bond --- gemcitabine prodrug --- metabolic stability --- pancreatic cancer cells --- pharmacokinetics --- peptide bond cleavage --- amide bond resonance --- twisted amides --- enzymes --- metal complexes --- catalysts --- amide C–N bond activation --- nickel catalysis --- amidation --- DFT study --- reaction thermodynamics --- amide resonance --- anomeric effect --- HERON reaction --- pyramidal amides --- physical organic chemistry --- reaction mechanism --- amide --- activation --- amidicity --- carbonylicity --- transamidation --- acyl transfer --- excited state --- Suzuki-Miyaura --- cross-coupling --- aryl esters --- C–O activation --- Pd-catalysis --- amides --- carbanions --- C–H acidity --- nitro-aci tautomerism --- molecular dynamics --- density-functional theory --- alkynes --- C–H bond cleavage --- C–N bond cleavage --- cyclopentadienyl complexes --- N-(1-naphthyl)acetamide --- rhodium --- [2+2+2] annulation --- amide bond --- sulfonamide bond --- alkynes --- addition reaction --- aminoacylation --- aminosulfonylation --- pre-catalysts --- palladium catalysis --- amide bond activation --- ester bond activation --- cross-coupling --- amide bond --- bridged lactams --- twisted amides --- amides --- Winkler-Dunitz parameters --- N–C activation --- hypersensitivity --- nitrogen heterocycles --- distortion --- bridged sultams --- amides --- C-N ? bond cleavage --- sodium --- crown ether --- amide hydrolysis --- model compound --- intramolecular catalysis --- twisted amide --- protease --- intein --- C-H functionalization --- directing groups --- amides --- transition metals --- catalysis

Advancements in Gel Science—A Special Issue in Memory of Toyoichi Tanaka

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ISBN: 9783039213436 / 9783039213443 Year: Pages: 178 DOI: 10.3390/books978-3-03921-344-3 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- Chemical Technology
Added to DOAB on : 2019-12-09 11:49:15
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A gel is a state of matter that consists of a three-dimensional cross-linked polymer network and a large amount of solvent. Because of their structural characteristics, gels play important roles in science and technology. The science of gels has attracted much attention since the discovery of the volume phase transition by Professor Toyoichi Tanala at MIT in 1978. MDPI planned to publish a Special Issue in Gels to celebrate the 40th anniversary of this discovery, which received submissions of 13 original papers and one review from various areas of science. We believe that readers will find this Special Issue informative as to the recent advancements of gel research and the broad background of gel science.

Keywords

gel --- thermoresponsive property --- monomer sequence --- co-crosslinking --- copolymerization --- acrylamide derivative --- swelling --- volume phase transition --- agarose gel --- compression --- solvent transport --- sucrose --- xylitol --- volume phase transition --- effects of electric charge --- swelling of thermosensitive gels --- sol-gel transition --- site-bond correlated-percolation model for polymer gelation --- gelation temperature --- cloud point temperature --- spinodal temperature --- spinodal decomposition --- janus particle --- anisotropic shape --- phase separation --- wetting --- micrometric confinement --- micropipette aspiration --- PVA gel --- gamma ray sterilization --- artificial hydrogel cartilage --- frictional property --- wear --- xerogel --- Brunauer-Emmett-Teller theory --- Barrett-Joyner-Halenda analysis --- temperature --- solids content --- drying --- solvent exchange --- microgel --- electrophoresis --- light scattering --- paint coating --- wrinkle --- swelling --- buckling --- Sephadex® (crosslinked dextran) --- crosslink density (density of crosslinks) --- ice grain --- ice crystallization during rewarming --- glassy water --- X-ray CT --- XRD --- poly(vinyl alcohol) --- chemical gel --- microcrystallite --- hydrogen bond --- swelling behavior --- hysteresis --- hydrogel --- friction --- fatigue --- wear --- fracture --- crack --- adhesion --- delamination --- poly (acryl amide) gel --- time domain reflectometry (TDR) of dielectric spectroscopy --- pulse field gradient spin echo method of nuclear magnetic resonance (PFG-NMR) --- scaling analysis --- fractal analysis --- heterogeneous gelation dynamics --- moving boundary picture --- phase transition dynamics --- kinetic coefficient --- blood coagulation --- n/a

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