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Author Correction: Hybrid quantum systems with high-T c superconducting resonators. Sci Rep 2023; 13:17407. [PMID: 37833386 PMCID: PMC10575915 DOI: 10.1038/s41598-023-44720-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023] Open
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Hybrid quantum systems with high-T[Formula: see text] superconducting resonators. Sci Rep 2023; 13:14366. [PMID: 37658090 PMCID: PMC10474070 DOI: 10.1038/s41598-023-41472-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/27/2023] [Indexed: 09/03/2023] Open
Abstract
Superconducting microwave resonators are crucial elements of microwave circuits, offering a wide range of potential applications in modern science and technology. While conventional low-T[Formula: see text] superconductors are mainly employed, high-T[Formula: see text] cuprates could offer enhanced temperature and magnetic field operating ranges. Here, we report the realization of [Formula: see text] superconducting coplanar waveguide resonators, and demonstrate a continuous evolution from a lossy undercoupled regime, to a lossless overcoupled regime by adjusting the device geometry, in good agreement with circuit model theory. A high-quality factor resonator was then used to perform electron spin resonance measurements on a molecular spin ensemble across a temperature range spanning two decades. We observe spin-cavity hybridization indicating coherent coupling between the microwave field and the spins in a highly cooperative regime. The temperature dependence of the Rabi splitting and the spin relaxation time point toward an antiferromagnetic coupling of the spins below 2 K. Our findings indicate that high-Tc superconducting resonators hold great promise for the development of functional circuits. Additionally, they suggest novel approaches for achieving hybrid quantum systems based on high-T[Formula: see text] superconductors and for conducting electron spin resonance measurements over a wide range of magnetic fields and temperatures.
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139P First-in-human (FIH), pharmacokinetic (PK) and pharmacodynamic (PD) study of IOA-244, a phosphoinositide 3-kinase delta (PI3Kδ) inhibitor, in patients with advanced metastatic mesothelioma, uveal and cutaneous melanoma. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.10.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Collective Spin Modes of a Trapped Quantum Ferrofluid. PHYSICAL REVIEW LETTERS 2018; 121:013201. [PMID: 30028151 DOI: 10.1103/physrevlett.121.013201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 06/08/2023]
Abstract
We report on the observation of a collective spin mode in a spinor Bose-Einstein condensate. Initially, all spins point perpendicular to the external magnetic field. The lowest energy mode consists of a sinusoidal oscillation of the local spin around its original axis, with an oscillation amplitude that linearly depends on the spatial coordinates. The frequency of the oscillation is set by the zero-point kinetic energy of the BEC. The observations are in excellent agreement with hydrodynamic equations. The observed spin mode has a universal character, independent of the atomic spin and spin-dependent contact interactions.
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Competition between Bose-Einstein Condensation and Spin Dynamics. PHYSICAL REVIEW LETTERS 2016; 117:185302. [PMID: 27834992 DOI: 10.1103/physrevlett.117.185302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Indexed: 06/06/2023]
Abstract
We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation by rapidly cooling a chromium multicomponent Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin-excited states. Small metastable spinor condensates are, nevertheless, produced, and they manifest in strong spin fluctuations.
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Cooling of a Bose-Einstein Condensate by Spin Distillation. PHYSICAL REVIEW LETTERS 2015; 115:243002. [PMID: 26705630 DOI: 10.1103/physrevlett.115.243002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Indexed: 06/05/2023]
Abstract
We propose and experimentally demonstrate a new cooling mechanism leading to purification of a Bose-Einstein condensate (BEC). Our scheme starts with a BEC polarized in the lowest energy spin state. Spin excited states are thermally populated by lowering the single particle energy gap set by the magnetic field. Then, these spin-excited thermal components are filtered out, which leads to an increase of the BEC fraction. We experimentally demonstrate such cooling for a spin 3 ^{52}Cr dipolar BEC. Our scheme should be applicable to Na or Rb, with the perspective to reach temperatures below 1 nK.
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Nonequilibrium quantum magnetism in a dipolar lattice gas. PHYSICAL REVIEW LETTERS 2013; 111:185305. [PMID: 24237534 DOI: 10.1103/physrevlett.111.185305] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/06/2013] [Indexed: 06/02/2023]
Abstract
We report on the realization of quantum magnetism using a degenerate dipolar gas in an optical lattice. Our system implements a lattice model resembling the celebrated t-J model. It is characterized by a nonequilibrium spinor dynamics resulting from intersite Heisenberg-like spin-spin interactions provided by nonlocal dipole-dipole interactions. Moreover, due to its large spin, our chromium lattice gases constitute an excellent environment for the study of quantum magnetism of high-spin systems, as illustrated by the complex spin dynamics observed for doubly occupied sites.
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Anisotropic excitation spectrum of a dipolar quantum Bose gas. PHYSICAL REVIEW LETTERS 2012; 109:155302. [PMID: 23102324 DOI: 10.1103/physrevlett.109.155302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Indexed: 06/01/2023]
Abstract
We measure the excitation spectrum of a dipolar chromium Bose-Einstein condensate with Raman-Bragg spectroscopy. The energy spectrum depends on the orientation of the dipoles with respect to the excitation momentum, demonstrating an anisotropy that originates from the dipole-dipole interactions between the atoms. We compare our results with the Bogoliubov theory based on the local density approximation and, at large excitation wavelengths, with the numerical simulations of the time-dependent Gross-Pitaevskii equation. Our results show an anisotropy of the speed of sound.
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Thermodynamics of a Bose-Einstein condensate with free magnetization. PHYSICAL REVIEW LETTERS 2012; 108:045307. [PMID: 22400858 DOI: 10.1103/physrevlett.108.045307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Indexed: 05/31/2023]
Abstract
We study thermodynamic properties of a gas of spin 3(52)Cr atoms across Bose-Einstein condensation. Magnetization is free, due to dipole-dipole interactions. We show that the critical temperature for condensation is lowered at extremely low magnetic fields, when the spin degree of freedom is thermally activated. The depolarized gas condenses in only one spin component, unless the magnetic field is set below a critical value, below which a nonferromagnetic phase is favored. Finally, we present a spin thermometry efficient even below the degeneracy temperature.
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Spontaneous demagnetization of a dipolar spinor Bose gas in an ultralow magnetic field. PHYSICAL REVIEW LETTERS 2011; 106:255303. [PMID: 21770651 DOI: 10.1103/physrevlett.106.255303] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Indexed: 05/31/2023]
Abstract
We study the spinor properties of S = 3 (52)Cr condensates, in which dipole-dipole interactions allow changes in magnetization. We observe a demagnetization of the Bose-Einstein condensate (BEC) when the magnetic field is quenched below a critical value corresponding to a phase transition between a ferromagnetic and a nonpolarized ground state, which occurs when spin-dependent contact interactions overwhelm the linear Zeeman effect. The critical field is increased when the density is raised by loading the BEC in a deep 2D optical lattice. The magnetization dynamics is set by dipole-dipole interactions.
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Synthesis of novel amphiphilic di-block and multiarmed star-shaped copolymers based on polyisobutylene and poly(ethylene oxide). ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.19971220157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Spin relaxation and band excitation of a dipolar Bose-Einstein condensate in 2D optical lattices. PHYSICAL REVIEW LETTERS 2011; 106:015301. [PMID: 21231749 DOI: 10.1103/physrevlett.106.015301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 11/25/2010] [Indexed: 05/30/2023]
Abstract
We observe interband transitions mediated by dipole-dipole interactions for an array of 1D quantum gases of chromium atoms, trapped in a 2D optical lattice. Interband transitions occur when dipolar relaxation releases an energy larger than the lattice band gap. For symmetric lattice sites, and a magnetic field parallel to the lattice axis, we compare the measured dipolar relaxation rate with a Fermi golden rule calculation. Below a magnetic field threshold, we obtain an almost complete suppression of dipolar relaxation, leading to metastable 1D gases in the highest Zeeman state.
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Bioinformatic strategies to provide functional clues to the unknown genes inPlasmodium falciparumgenome. Parasite 2010; 17:273-83. [DOI: 10.1051/parasite/2010174273] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Collective excitations of a dipolar Bose-Einstein condensate. PHYSICAL REVIEW LETTERS 2010; 105:040404. [PMID: 20867824 DOI: 10.1103/physrevlett.105.040404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Indexed: 05/29/2023]
Abstract
We have measured the effect of dipole-dipole interactions on the frequency of a collective mode of a Bose-Einstein condensate. At relatively large numbers of atoms, the experimental measurements are in good agreement with zero temperature theoretical predictions based on the Thomas-Fermi approach. Experimental results obtained for the dipolar shift of a collective mode show a larger dependency to both the trap geometry and the atom number than the ones obtained when measuring the modification of the condensate aspect ratio due to dipolar forces. These findings are in good agreement with simulations based on a Gaussian ansatz.
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Exploring functional genomics for drug target and therapeutics discovery in Plasmodia. Acta Trop 2008; 105:113-23. [PMID: 18083131 DOI: 10.1016/j.actatropica.2007.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 10/17/2007] [Accepted: 10/30/2007] [Indexed: 02/04/2023]
Abstract
Functional genomics approaches are indispensable tools in the drug discovery arena and have recently attained increased attention in antibacterial drug discovery research. However, the application of functional genomics to post-genomics research of Plasmodia is still in comparatively early stages. Nonetheless, with this genus having the most species sequenced of any eukaryotic organism so far, the Plasmodia could provide unique opportunities for the study of intracellular eukaryotic pathogens. This review presents the status quo of functional genomics of the malaria parasite including descriptions of the transcriptome, proteome and interactome. We provide examples for the in silico mining of the X-ome data sets and illustrate how X-omic data from drug challenged parasites might be used in elucidating amongst others, the mode-of-action of inhibitory compounds, validate potential targets and discover novel targets/therapeutics.
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Two types of MGDG synthase genes, found widely in both 16:3 and 18:3 plants, differentially mediate galactolipid syntheses in photosynthetic and nonphotosynthetic tissues in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2001; 98:10960-5. [PMID: 11553816 PMCID: PMC58581 DOI: 10.1073/pnas.181331498] [Citation(s) in RCA: 262] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Arabidopsis, monogalactosyldiacylglycerol (MGDG) is synthesized by a multigenic family of MGDG synthases consisting of two types of enzymes differing in their N-terminal portion: type A (atMGD1) and type B (atMGD2 and atMGD3). The present paper compares type B isoforms with the enzymes of type A that are known to sit in the inner membrane of plastid envelope. The occurrence of types A and B in 16:3 and 18:3 plants shows that both types are not specialized isoforms for the prokaryotic and eukaryotic glycerolipid biosynthetic pathways. Type A atMGD1 gene is abundantly expressed in green tissues and along plant development and encodes the most active enzyme. Its mature polypeptide is immunodetected in the envelope of chloroplasts from Arabidopsis leaves after cleavage of its transit peptide. atMGD1 is therefore likely devoted to the massive production of MGDG required to expand the inner envelope membrane and build up the thylakoids network. Transient expression of green fluorescent protein fusions in Arabidopsis leaves and in vitro import experiments show that type B precursors are targeted to plastids, owing to a different mechanism. Noncanonical addressing peptides, whose processing could not be assessed, are involved in the targeting of type B precursors, possibly to the outer envelope membrane where they might contribute to membrane expansion. Expression of type B enzymes was higher in nongreen tissues, i.e., in inflorescence (atMGD2) and roots (atMGD3), where they conceivably influence the eukaryotic structure prominence in MGDG. In addition, their expression of type B enzymes is enhanced under phosphate deprivation.
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Abstract
Protozoan parasites of the phylum Apicomplexa include pathogens such as Plasmodium, Toxoplasma and Cryptosporidium. They have been shown to contain a vestigial nonphotosynthetic plastid, the apicoplast, which might have arisen by secondary endosymbiosis. Little is known about the function of the apicoplast but the parasites exhibit delayed cell death when their apicoplast is impaired. The discovery of the apicoplast opens an unexpected opportunity to link current fundamental research on plant and algal plastids to the physiology of apicomplexans. For example, the apicoplast might provide new targets for innovative drugs that act as herbicides and do not affect the mammalian host.
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[An unusual shoulder stiffness: metastasis in the infraspinatus muscle as the first clinical manifestation of lung carcinoma]. REVUE DE CHIRURGIE ORTHOPEDIQUE ET REPARATRICE DE L'APPAREIL MOTEUR 2001; 87:79-83. [PMID: 11240541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
PURPOSE OF THE STUDY Malignant metastases are rarely located in skeletal muscles. We report a case of lung adenocarcinoma disclosed by metastatic dissemination to the infraspinatus muscle. CASE REPORT A 66-year-old man consulted for a painful stiff right shoulder. Pain had developed progressively and did not respond to class 2 antalgesics. There was a complete loss of passive and active medial rotation while the other shoulder amplitudes were normal. A discrete tumefaction was palpated in the infraspinatus fossa. Magnetic resonance imaging alone was able to evidence an intramuscular tumoral formation within the infraspinatus. Surgical excision led to the diagnosis of metastatic adenocarcinoma of the lung and provided rapid pain relief. Nearly normal medial rotation amplitude was recovered. The patient died at 10 months from complications related to the lung adenocarcinoma. DISCUSSION This is the first report of metastatic lung carcinoma located in the infraspinatus muscle. The clinical presentation was very exceptional, no similar cases being reported in the literature. In bloc surgical resection appears to be the best therapeutic approach, allowing positive diagnosis and relief of pain and stiffness.
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[Concerning "Aggressive osteoblastoma of the carpal scaphoid bone"]. REVUE DE CHIRURGIE ORTHOPEDIQUE ET REPARATRICE DE L'APPAREIL MOTEUR 2000; 86:851. [PMID: 11221796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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The multigenic family of monogalactosyl diacylglycerol synthases. Biochem Soc Trans 2000; 28:732-8. [PMID: 11171188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Because the synthesis of monogalactosyldiacylglycerol (MGDG) is unique to plants, identified as an important marker of the plastid envelope, involved in a key step of plastid biogenesis and is the most abundant lipid on earth, MGDG synthase activity was extensively analysed at the biochemical and physiological levels. In the present paper, we present our current knowledge on the MGDG synthase's function, structure and topology in envelope membranes, and discuss possible roles in plant cell glycerolipid metabolism. The recent discovery of a multigenic family of MGDG synthases raised the possibility that multiple isoenzymes might carry out MGDG synthesis in various tissues and developmental stages.
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Protein import into plastids: general versus specialized translocation. TRENDS IN PLANT SCIENCE 2000; 5:461. [PMID: 11077246 DOI: 10.1016/s1360-1385(00)01787-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Synthesis and characterization of poly(copolyethers-block-polyamides) II. Characterization and properties of the multiblock copolymers. POLYMER 2000. [DOI: 10.1016/s0032-3861(99)00526-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Recurrent osteoblastoma of the hamate bone. JOURNAL OF HAND SURGERY (EDINBURGH, SCOTLAND) 1999; 24:757-8. [PMID: 10672826 DOI: 10.1054/jhsb.1999.0324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Biochemical and topological properties of type A MGDG synthase, a spinach chloroplast envelope enzyme catalyzing the synthesis of both prokaryotic and eukaryotic MGDG. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 265:990-1001. [PMID: 10518794 DOI: 10.1046/j.1432-1327.1999.00801.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
MGDG synthase, the enzyme that catalyzes the synthesis of the major chloroplast membrane lipid monogalactosyldiacylglycerol (MGDG), is encoded by a multigenic family. We have analyzed the biochemical properties, subcellular localization and membrane topology of a spinach chloroplast MGDG synthase, a representative member of the type A family from Spinacia oleracea (soMGD A), using a recombinant protein that was functionally overexpressed in Escherichia coli and specific polyclonal antibodies. We demonstrated that soMGD A could catalyze the synthesis of both 'prokaryotic' and 'eukaryotic' MGDG molecular species in vitro, with a selectivity for diacylglycerol similar to that of purified chloroplast envelope MGDG synthase activity. Furthermore, soMGD A was shown to be sensitive to chemical reagents (dithiothreitol, N-ethylmaleimide and o-phenanthroline) known to affect MGDG synthesis by the partially purified enzyme, as well as in isolated chloroplast envelope membranes. In spinach chloroplasts, soMGD A was localized by Western blot analysis in the inner envelope membrane. Topological studies demonstrated that soMGD A is a monotopic enzyme, embedded within one leaflet of the inner envelope membrane from spinach chloroplasts, a structure which may involve amphipathic alpha helices. We further demonstrated that in vitro, soMGD A precursor is imported and processed to its correct mature form in intact chloroplasts. These results show that soMGD A corresponds to a mature polypeptide of approximately 45 kDa. In addition, inactivation kinetics after gamma-ray irradiation strongly suggest that both native chloroplast envelope MGDG synthase and recombinant soMGD A have a functional molecular mass of 95-100 kDa, indicating that they are probably active as homodimers made of two 45-kDa subunits. This study suggests that, in spite of the growing evidence that MGDG synthesis is catalyzed by a multigenic family of enzymes, in spinach leaves both prokaryotic and eukaryotic MGDG syntheses could be attributable to a unique dimeric enzyme, provided that diacylglycerol is transported from the outer membrane to the inner membrane of the chloroplast envelope.
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Spanish families with cavernous angiomas do not share the Hispano-American CCM1 haplotype. J Neurol Neurosurg Psychiatry 1999; 67:551-2. [PMID: 10610389 PMCID: PMC1736550 DOI: 10.1136/jnnp.67.4.551] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Modulation of GT-1 DNA-binding activity by calcium-dependent phosphorylation. PLANT MOLECULAR BIOLOGY 1999; 40:373-86. [PMID: 10437822 DOI: 10.1023/a:1006131330930] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The analysis of pea rbcS-3A promoter sequence showed that BoxII was necessary for the control of rbcS-3A gene expression by light. GT-1, a DNA-binding protein that interacts with BoxII in vitro, is a good candidate for being a light-modulated molecular switch controlling gene expression. However, the relationship between GT-1 activity and light-responsive gene activation still remains hypothetical. Because no marked de novo synthesis was detected after light treatment, light may induce post-translational modifications of GT-1 such as phosphorylation or dephosphorylation. Here, we show that recombinant GT-1 (hGT-1) of Arabidopsis can be phosphorylated by various mammalian kinase activities in vitro. Whereas phosphorylation by casein kinase II had no apparent effect on hGT-1 DNA binding, phosphorylation by calcium/calmodulin kinase II (CaMKII) increased the binding activity 10-20-fold. Mass spectrometry analyses of the phosphorylated hGT-1 showed that amongst the 6 potential phosphorylatable residues (T86, T133, S175, T179, S198 and T278), only T133 and S198 are heavily modified. Analyses of mutants altered at T86, T133, S175, T179, S198 and T278 demonstrated that phosphorylation of T133 can account for most of the stimulation of DNA-binding activity by CaMKII, indicating that this residue plays an important role in hGT-1/BoxII interaction. We further showed that nuclear GT-1 DNA-binding activity to BoxII was reduced by treatment with calf intestine phosphatase in extracts prepared from light-grown plants but not from etiolated plants. Taken together, our results suggest that GT-1 may act as a molecular switch modulated by calcium-dependent phosphorylation and dephosphorylation in response to light signals.
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Genetic heterogeneity and absence of founder effect in a series of 36 French cerebral cavernous angiomas families. Eur J Hum Genet 1999; 7:499-504. [PMID: 10352941 DOI: 10.1038/sj.ejhg.5200324] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Cerebral cavernous angiomas malformations (CCM) can be inherited as an autosomal dominant condition. CCM1, a yet unidentified gene mapping on 7q21-q22, was shown to be involved in all CCM Hispano-American families, with a strong founder effect. Genetic heterogeneity in non Hispano-American families was established in two families. We conducted a genetic linkage analysis on 36 French CCM families using eight microsatellite markers mapping within the CCM1 interval. Admixture analysis showed that 65% of these families were linked to the CCM1 locus. Haplotypes analysis of CCM1-linked families did not show any evidence for a strong founder effect.
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Abstract
Abscisic acid (ABA) is the primary hormone that mediates plant responses to stresses such as cold, drought, and salinity. Single-cell microinjection experiments in tomato were used to identify possible intermediates involved in ABA signal transduction. Cyclic ADP-ribose (cADPR) was identified as a signaling molecule in the ABA response and was shown to exert its effects by way of calcium. Bioassay experiments showed that the amounts of cADPR in Arabidopsis thaliana plants increased in response to ABA treatment and before ABA-induced gene expression.
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Notch3 mutations in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a mendelian condition causing stroke and vascular dementia. Ann N Y Acad Sci 1997; 826:213-7. [PMID: 9329692 DOI: 10.1111/j.1749-6632.1997.tb48472.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited condition whose key features include recurrent subcortical ischemic events, migraine attacks and vascular dementia in association with diffuse white-matter abnormalities seen on neuroimaging. Pathologic examination shows multiple small deep cerebral infarcts, a leukoencephalopathy and a nonatherosclerotic nonamyloid angiopathy involving mainly the media of small cerebral arteries. To progress in understanding the pathophysiological mechanisms of this condition, we undertook the identification of the mutated gene. We mapped the CADASIL gene on chromosome 19p13.1. More than 120 families have been referred to our lab. Genetic linkage analysis of 33 of these families allowed us to reduce the size of the genetic interval to less than 1 cM and to demonstrate the genetic homogeneity of this condition. In the absence of any candidate gene, we undertook positional cloning of this gene. We identified, within the CADASIL critical region, the human Notch3 gene, whose sequence analysis revealed deleterious mutations in CADASIL families co-segregating with the affected phenotype. These data establish that this gene causes CADASIL. Identification of the CADASIL gene will provide a valuable diagnostic tool for clinicians and could be used to estimate the prevalence of this underdiagnosed condition. It should help in the understanding of pathophysiological mechanisms of CADASIL and vascular dementia.
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Abstract
CADASIL, a recently identified autosomal dominant condition characterized by the recurrence of subcortical infarcts leading to dementia, was previously mapped to chromosome 19p13.1 within a 2-cM interval, D19S226-D19S199. No recombination event was observed with D19S841, a highly polymorphic microsatellite marker isolated from a cosmid mapped to this region. We recently identified within this cosmid a conserved sequence that we used to screen a fetal brain cDNA library and isolated an ubiquitous and abundantly transcribed gene. We did not detect any mutation of this gene in CADASIL patients, suggesting that it is not implicated in this disorder. Interestingly, this gene encodes a putative protein homologous to several thiamine pyrophosphate-binding proteins previously identified in bacteria, yeast, and plants. The proteins with the highest degree of similarity were the acetolactate synthase enzymes which, in prokaryotes, are involved in the branched chain amino acid biosynthetic pathway, raising fascinating questions on the yet unknown function of this gene in mammals.
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Definitions of terms relating to degradation, aging, and related chemical transformations of polymers (IUPAC Recommendations 1996). PURE APPL CHEM 1996. [DOI: 10.1351/pac199668122313] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Enzyme-catalyzed synthesis of aliphatic polyesters in organic media: Study of transesterification equilibrium shift and characterization of cyclic compounds. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/pola.1995.080331602] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry of synthetic polyesters. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/0168-1176(95)04159-i] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Global vector field reconstruction from a chaotic experimental signal in copper electrodissolution. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 51:4262-4266. [PMID: 9963137 DOI: 10.1103/physreve.51.4262] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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The catalytic site of monogalactosyldiacylglycerol synthase from spinach chloroplast envelope membranes. Biochemical analysis of the structure and of the metal content. J Biol Chem 1995; 270:5714-22. [PMID: 7890698 DOI: 10.1074/jbc.270.11.5714] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have analyzed the structure of the active site of monogalactosyldiacylglycerol (MGDG) synthase from spinach chloroplast envelope. Since purification of this membrane-embedded enzyme yielded such low amounts of protein that analyses of the amino acid sequence were so far impossible, we used indirect strategies. Analyses of the inhibition of MGDG synthase by UDP and of its inactivation by citraconic anhydride first indicated that the enzyme contained two functionally independent and topologically distinct binding sites for each substrate. Whereas MGDG synthase binds both the nucleotidic part of UDP-Gal and the acyl chains of 1,2-diacylglycerol, UDP is a competitive inhibitor relatively to UDP-Gal, while it does not compete with 1,2-diacylglycerol for binding on the enzyme. The UDP-Gal-binding site contains lysine residues, as demonstrated for UDP-Gal-binding sites from all galactosyltransferases studied so far. Radiolabeling of MGDG synthase by sulfur labeling reagent, a 35S-labeled lysine-blocking reagent, confirmed that MGDG synthase was a polypeptide with a low molecular mass (around 20 kDa). The 1,2-diacylglycerol-binding site contains reduced cysteines and at least one metal. The divalent cation(s) associated to apo-MGDG synthase was not unambiguously identified, but the results suggest that it could be zinc. Therefore, MGDG synthase presents some structural features in common with diacylglycerol-manipulating enzymes, such as protein kinase C and 1,2-diacylglycerol kinase, which are characterized by the presence of a ubiquitous Cys6His2 domain involved in zinc coordination in their 1,2-diacylglycerol-binding domains.
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Comparison of the kinetic properties of MGDG synthase in mixed micelles and in envelope membranes from spinach chloroplast. FEBS Lett 1994; 352:307-10. [PMID: 7925991 DOI: 10.1016/0014-5793(94)00978-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have applied the 'membrane partition' kinetic modelling approach proposed by Heirwegh et al. [(1988) Biochem. J. 254, 101-108] to MGDG synthase in isolated envelope vesicles. Comparison of the kinetic parameters obtained for MGDG synthase assayed in purified envelope membranes and in mixed-micelles demonstrates that the latter are relevant to the situation in envelope membranes and that MGDG synthase has a very high affinity for dilinoleoylglycerol. Our results provide additional evidence for the hypothesis that the high affinity of the envelope MGDG synthase for dilinoleoylglycerol could be responsible for the presence of C18 fatty acids at both the sn-1 and sn-2 position of the glycerol backbone in MGDG.
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Kinetic properties of monogalactosyldiacylglycerol synthase from spinach chloroplast envelope membranes. J Biol Chem 1994; 269:5788-98. [PMID: 8119920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have investigated the functioning of monogalactosyldiacylglycerol (MGDG) synthase activity partially purified from spinach chloroplast envelope membranes, using mixed micelles containing diacylglycerol (the substrate for MGDG synthase), CHAPS (3-[(cholamidopropyl)dimethylammonio]-1- propanesulfonic acid), and phosphatidylglycerol. The presence of this anionic phospholipid was essential for optimal MGDG synthase activity because it strongly improves diacylglycerol solubilization by CHAPS. We have demonstrated that the "surface dilution" kinetic model proposed by Deems et al. (Deems, R.A., Eaton, B.R., and Dennis, E.A. (1975) J. Biol. Chem. 250, 9013-9020) is valid for MGDG synthase assayed in mixed micelles within a narrow range of CHAPS concentration. However, the experimental conditions we have set up in this study led to the description of defined equilibrium and kinetic parameters of the interaction of the envelope MGDG synthase with diacylglycerol. Two-substrate kinetic studies were performed with varied UDP-galactose molar concentrations and varied dioleoylglycerol surface concentrations. The families of reciprocal plots obtained were shown to intersect at a single point of the 1/[substrate] axis thus demonstrating that MGDG synthase is a sequential, either random or ordered, bireactant system. Therefore, MGDG synthase possesses two distinct and independent substrate-binding sites, a hydrophilic one for UDP-galactose and a hydrophobic one for diacylglycerol. The dependence of kinetic parameters on the diacylglycerol mol fraction allows a comparison of the affinity of the enzyme for a wide range of diacylglycerol molecular species. The Km values obtained were ranging between 0.0089 mol fraction (52 microM) for dilinoleoylglycerol (18:2/18:2) to 0.0666 mol fraction (416 microM) for distearoylglycerol (18:0/18:0), but the differences observed were not really related to the unsaturation of the molecule since the Km value for dilinoleoylglycerol was much lower than that (0.040 mol fraction) for dilinoleoylglycerol (18:3/18:3). The Km values for dioleoylglycerol (18:1/18:1) and for the diacylglycerol molecular species synthesized within chloroplasts, i.e. containing 18:1/16:0, were in the average range, i.e. lower than 0.030 mol fraction (around 170 microM).
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Kinetic properties of monogalactosyldiacylglycerol synthase from spinach chloroplast envelope membranes. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37531-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Importance of diacylglycerol in glycerolipid biosynthesis by spinach chloroplast envelope membranes. Prog Lipid Res 1994; 33:105-18. [PMID: 8190730 DOI: 10.1016/0163-7827(94)90013-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Structural study of telechelic oligoisobutylenes in relation with the experimental conditions of their synthesis. Eur Polym J 1986. [DOI: 10.1016/0014-3057(86)90065-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Synthesis of poly(sulphone-b-siloxane)s—II. Synthesis of poly(sulphone-b-siloxane) by reaction of α,ω-diphenol oligosulphones with α,ω-diepoxy oligosiloxanes. Eur Polym J 1985. [DOI: 10.1016/0014-3057(85)90232-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Synthesis of poly(sulphone-b-siloxane)s — III. Synthesis of poly(sulphone-b-siloxane) by reaction of α,ω-diallyl oligosulphones with α,ω-disilane oligosiloxanes. Eur Polym J 1985. [DOI: 10.1016/0014-3057(85)90233-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Synthesis of poly(sulphone-b-siloxane)s—I. Model study of the epoxy-phenol reaction in the melt. Eur Polym J 1985. [DOI: 10.1016/0014-3057(85)90231-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Synthesis of mono and difunctional oligoisobutylenes—IV. Modification of α,ω-dichlorooligoisobutylene by reaction with maleic anhydride. Preliminary study on block polycondensation. Eur Polym J 1984. [DOI: 10.1016/0014-3057(84)90049-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Synthesis and characterization of poly(butadiene-b-sulphone) by block-copolycondensation—I. Synthesis from α,ω-dichlorocarbonyl oligobutadienes and α,ω-diphenol oligoarylethersulphones. Eur Polym J 1984. [DOI: 10.1016/0014-3057(84)90053-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Synthesis and characterization of poly(butadiene-b-sulphone) by block-copolycondensation—II. Synthesis from α,ω-dicarboxylic oligobutadienes and α,ω-diepoxy oligosulphones. Eur Polym J 1984. [DOI: 10.1016/0014-3057(84)90054-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Synthesis of mono and difunctional oligoisobutylenes—III. Modification of α-chlorooligoisobutylene by reaction with maleic anhydride. Eur Polym J 1984. [DOI: 10.1016/0014-3057(84)90048-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Fundamental study of the reaction of epoxy-bearing polymers with 4-hydroxybenzoic acid application to the synthesis of chelating polymers—II. Eur Polym J 1983. [DOI: 10.1016/0014-3057(83)90004-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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