Differential cargo mobilisation within Weibel-Palade bodies after transient fusion with the plasma membrane.

Inflammatory chemokines can be selectively released from Weibel-Palade bodies (WPBs) during kiss-and-run exocytosis. Such selectivity may arise from molecular size filtering by the fusion pore, however differential intra-WPB cargo re-mobilisation following fusion-induced structural changes within the WPB may also contribute to this process. To determine whether WPB cargo molecules are differentially re-mobilised, we applied FRAP to residual post-fusion WPB structures formed after transient exocytosis in which some or all of the fluorescent cargo was retained. Transient fusion resulted in WPB collapse from a rod to a spheroid shape accompanied by substantial swelling (>2 times by surface area) and membrane mixing between the WPB and plasma membranes. Post-fusion WPBs supported cumulative WPB exocytosis. To quantify diffusion inside rounded organelles we developed a method of FRAP analysis based on image moments. FRAP analysis showed that von Willebrand factor-EGFP (VWF-EGFP) and the VWF-propolypeptide-EGFP (Pro-EGFP) were immobile in post-fusion WPBs. Because Eotaxin-3-EGFP and ssEGFP (small soluble cargo proteins) were largely depleted from post-fusion WPBs, we studied these molecules in cells preincubated in the weak base NH4Cl which caused WPB alkalinisation and rounding similar to that produced by plasma membrane fusion. In these cells we found a dramatic increase in mobilities of Eotaxin-3-EGFP and ssEGFP that exceeded the resolution of our method (∼ 2.4 µm2/s mean). In contrast, the membrane mobilities of EGFP-CD63 and EGFP-Rab27A in post-fusion WPBs were unchanged, while P-selectin-EGFP acquired mobility. Our data suggest that selective re-mobilisation of chemokines during transient fusion contributes to selective chemokine secretion during transient WPB exocytosis. Selective secretion provides a mechanism to regulate intravascular inflammatory processes with reduced risk of thrombosis

Expanding 1,2,4-triketone Toolbox for use as Aluorinated Building Blocks in the Synthesis of Pyrazoles, Pyridazinones and β-diketohydrazones

Fluorinated lithium β-diketonates bearing a methyl acetal group behave in the condensation reactions with hydrazines as trielectrophilic building blocks for the preparation of pyrazoles, pyridazinones and β-diketohydrazones. For the first time, solvent-induced regioisomeric and heterocyclic ring size-controlled formation was observed for 1,2,4-triketone analogues. Fluoroalkylated acetyl NH-pyrazoles or substituted 5-RF-pyrazoles were obtained from the acid-catalyzed cyclocondensation of lithium β-diketonates with (aryl)hydrazines in ethanol. In methanol solvent acetyl-containing 3-CF3-pyrazoles were isolated because of inverse nucleophilic attack of arylhydrazines. The use of aprotic acetonitrile in the condensation resulted in regioselective trifluorinated pyridazinones and fluorinated β-diketohydrazones formation via initial acetal fragment interaction with N,N-dinucleophile. © 2021 Elsevier B.V.This work carried out in the framework of the basic theme of the Russian Academy of Sciences (state registration № AAAA-A19-119011790132-7). Single-crystal X-ray diffraction analysis for 3g, 3f and 10a was performed using the equipment of the JRC PMR IGIC RAS. Single-crystal X-ray diffraction analysis for 5d, 7a, 9a and physicochemical studies were carried out using the equipments of the Center for Joint Use "Spectroscopy and Analysis of Organic Compounds" at the Postovsky Institute of Organic Synthesis UB RAS

Perfluoroalkyl Chain Length Effect on Crystal Packing and [LnO8] Coordination Geometry in Lanthanide-Lithium β-Diketonates: Luminescence and Single-Ion Magnet Behavior

Functionalized perfluoroalkyl lithium β-diketonates (LiL) react with lanthanide(III) salts (Ln = Eu, Gd, Tb, Dy) in methanol to give heterobimetallic Ln-Li complexes of general formula [(LnL3)(LiL)(MeOH)]. The length of fluoroalkyl substituent in ligand was found to affect the crystal packing of complexes. Photoluminescent and magnetic properties of heterobimetallic β-diketonates in the solid state are reported. The effect of the geometry of the [LnO8] coordination environment of heterometallic β-diketonates on the luminescent properties (quantum yields, phosphorescence lifetimes for Eu, Tb, Dy complexes) and single-ion magnet behavior (Ueff for Dy complexes) is revealed. © 2023 by the authors.Russian Academy of Sciences, РАН: AAAA-A19-119011790132-7This work carried out in the framework of the basic theme of the Russian Academy of Sciences (state registration № AAAA-A19-119011790132-7)

Tri- and tetranuclear heteropivalate complexes with core {Fe<inf>2</inf>Ni<inf>x</inf>O} (x = 1, 2): Synthesis, structure, magnetic and thermal properties

© 2018 Elsevier Ltd The reactions of complex [Fe2Ni(O)(Piv)6(Et2O)(H2O)2] (1) with 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy) gave the following new coordination compounds: the trinuclear complex [Fe2Ni(O)(Piv)6(phen)H2O]·(C2H5)2O (2), the tetranuclear ones [Fe2Ni2(OH)2(Piv)8(phen)2] (3) and [Fe2Ni2(OH)2(Piv)8(bpy)2] (4), depending on the crystallization conditions. According to single crystal X-ray diffraction data, all the compounds have molecular structures. The Mössbauer spectra of 1–3 correspond to high-spin Fe3+ ions in an octahedral environment consisting of oxygen atoms. The DC magnetic susceptibility studies and quantum-chemical analysis of intra- and intermolecular J pathways using broken-symmetry density functional theory (DFT) showed that all exchange interactions in tri- (1, 2) and tetranuclear (3) complexes are antiferromagnetic. The exchange coupling is weaker in 3 due to the lower ability of the bridging OH-groups to mediate superexchange. Thermal destruction processes have been studied for 2 and 3. The final products of thermolysis are the mixed oxide NiFe2O4

Tri- and tetranuclear heteropivalate complexes with core {Fe<inf>2</inf>Ni<inf>x</inf>O} (x = 1, 2): Synthesis, structure, magnetic and thermal properties

© 2018 Elsevier Ltd The reactions of complex [Fe2Ni(O)(Piv)6(Et2O)(H2O)2] (1) with 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy) gave the following new coordination compounds: the trinuclear complex [Fe2Ni(O)(Piv)6(phen)H2O]·(C2H5)2O (2), the tetranuclear ones [Fe2Ni2(OH)2(Piv)8(phen)2] (3) and [Fe2Ni2(OH)2(Piv)8(bpy)2] (4), depending on the crystallization conditions. According to single crystal X-ray diffraction data, all the compounds have molecular structures. The Mössbauer spectra of 1–3 correspond to high-spin Fe3+ ions in an octahedral environment consisting of oxygen atoms. The DC magnetic susceptibility studies and quantum-chemical analysis of intra- and intermolecular J pathways using broken-symmetry density functional theory (DFT) showed that all exchange interactions in tri- (1, 2) and tetranuclear (3) complexes are antiferromagnetic. The exchange coupling is weaker in 3 due to the lower ability of the bridging OH-groups to mediate superexchange. Thermal destruction processes have been studied for 2 and 3. The final products of thermolysis are the mixed oxide NiFe2O4

Towards bright dysprosium emitters: Single and combined effects of environmental symmetry, deuteration, and gadolinium dilution

With the aim of creating new light emitting systems, two new dysprosium complexes of formula [DyQcy3(H2O)] (1-Dy) and [H3O][DyQcy4] (2-Dy) (where HQcy = 1-phenyl-3-methyl-4-cyclohexylcarbonyl-pyrazol-5-one) have been synthesized and characterized by spectroscopy. The reaction conditions to address the synthesis toward these tris-(diketonate)dysprosium or tetrakis(diketonate)dysprosium complexes have been optimized. The Qcy ligand provides effective sensitization of the luminescence of Dy3+ ion. 1-Dy and 2-Dy have been investigated by single crystal X-ray diffraction analysis, both species being packed via a system of hydrogen bonds. The dependence of quantum yield and lifetime of the excited state of Dy3+ ions have been examined by implementing two common approaches: replacing protons with deuterium in the coordinated H2O or in cation H3O+ and diluting Dy3+ cations with Gd3+ ions, to suppress vibrational and concentration quenching, respectively. It has been found that deuteration turns out to be very effective on both quantum yield and lifetime, but only in the case of replacement of the inner-sphere water molecules. The strategy of gadolinium dilution leads in all cases to an increase in lifetime. In addition, the possibility of a subtle tuning of the luminescence color has been discovered due to the change in the gadolinium content and deuteration, and a white light luminescent (CIE 0.31, 0.34) composition has been obtained