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1.
Nature ; 618(7966): 712-715, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37286602

ABSTRACT

The most massive and shortest-lived stars dominate the chemical evolution of the pre-galactic era. On the basis of numerical simulations, it has long been speculated that the mass of such first-generation stars was up to several hundred solar masses1-4. The very massive first-generation stars with a mass range from 140 to 260 solar masses are predicted to enrich the early interstellar medium through pair-instability supernovae (PISNe)5. Decades of observational efforts, however, have not been able to uniquely identify the imprints of such very massive stars on the most metal-poor stars in the Milky Way6,7. Here we report the chemical composition of a very metal-poor (VMP) star with extremely low sodium and cobalt abundances. The sodium with respect to iron in this star is more than two orders of magnitude lower than that of the Sun. This star exhibits very large abundance variance between the odd- and even-charge-number elements, such as sodium/magnesium and cobalt/nickel. Such peculiar odd-even effect, along with deficiencies of sodium and α elements, are consistent with the prediction of primordial pair-instability supernova (PISN) from stars more massive than 140 solar masses. This provides a clear chemical signature indicating the existence of very massive stars in the early universe.

2.
Nucleic Acids Res ; 2024 Sep 25.
Article in English | MEDLINE | ID: mdl-39319582

ABSTRACT

Non-canonical nucleic acid structures, such as G-quadruplex (G4) and i-Motif (iM), have garnered significant research interest because of their unique structural properties and biological activities. Thousands of small molecules targeting G4/iM structures have been developed for various chemical and biological applications. In response to the growing interest in G4-targeting ligands, we launched the first G4 Ligand Database (G4LDB) in 2013. Here, we introduce G4LDB 3.0 (http://www.g4ldb.com), an upgraded version featuring extensive enhancements in content and functionality. The new version includes over 4800 G4/iM ligands and approximately 51 000 activity entries. Key upgrades include advanced search capabilities, dynamic knowledge graphs, enhanced data visualization, along with a new dynamic analysis function that automatically displays ligand structure clustering results and chemical space distribution. With these updates, G4LDB 3.0 further evolves into a comprehensive resource and valuable research tool. The significant improvements address the increasing demand for efficient data handling and user experience, highlighting the critical role of G4LDB in advancing research on G-quadruplexes and i-motifs.

3.
Nucleic Acids Res ; 50(D1): D150-D160, 2022 01 07.
Article in English | MEDLINE | ID: mdl-34718746

ABSTRACT

Noncanonical nucleic acid structures, such as G-quadruplex (G4) and i-Motif (iM), have attracted increasing research interests because of their unique structural and binding properties, as well as their important biological activities. To date, thousands of small molecules that bind to varying G4/iM structures have been designed, synthesized and tested for diverse chemical and biological uses. Because of the huge potential and increasing research interests on G4-targeting ligands, we launched the first G4 ligand database G4LDB in 2013. Here, we report a new version, termed G4LDB 2.2 (http://www.g4ldb.com), with upgrades in both content and function. Currently, G4LDB2.2 contains >3200 G4/iM ligands, ∼28 500 activity entries and 79 G4-ligand docking models. In addition to G4 ligand library, we have also added a brand new iM ligand library to G4LDB 2.2, providing a comprehensive view of quadruplex nucleic acids. To further enhance user experience, we have also redesigned the user interface and optimized the database structure and retrieval mechanism. With these improvements, we anticipate that G4LDB 2.2 will serve as a comprehensive resource and useful research toolkit for researchers across wide scientific communities and accelerate discovering and validating better binders and drug candidates.


Subject(s)
Databases, Genetic , G-Quadruplexes , Structure-Activity Relationship , Binding Sites/genetics , Humans , Ligands , Molecular Docking Simulation
4.
Microvasc Res ; 135: 104136, 2021 05.
Article in English | MEDLINE | ID: mdl-33450295

ABSTRACT

Reversine, or 2-(4-morpholinoanilino)-6cyclohexylaminopurine, is a 2,6-disubstituted purine derivative. This small molecule exhibits tumor-suppressive activities through different molecular mechanisms. In this study, in vitro and in vivo angiogenic models were used to elucidate the effect of Reversine on angiogenesis in the tumor suppression. Firstly, we grafted osteosarcoma-derived MNNG/HOS cell aggregates onto chick embryonic chorioallantoic membrane (CAM) to examine the vascularization of these grafts following Reversine treatment. Following culture, it was determined that Reversine inhibited MNNG/HOS grafts growth, and decreased the density of blood vessels in the chick CAM. We then used CAM and chick embryonic yolk-sac membrane (YSM) to investigate the effects of Reversine on angiogenesis. The results revealed Reversine inhibited the proliferation of endothelial cells, where cells were mainly arrested at G1/S phase of the cell cycle. Scratch-wound assay with HUVECs revealed that Reversine suppressed cell migration in vitro. Furthermore, endothelial cells tube formation assay and chick aortic arch sprouting assay demonstrated Reversine inhibited the sprouting, migration of endothelial cells. Lastly, qPCR and western blot analyses showed BMP-associated Smad1/5/8 signaling expressions were up-regulated by Reversine treatment. Our results showed that Reversine could suppress tumor growth by inhibiting angiogenesis through BMP signaling, and suggests a potential use of Reversine as an anti-tumor therapy.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Bone Morphogenetic Proteins/metabolism , Bone Neoplasms/drug therapy , Cell Proliferation/drug effects , Human Umbilical Vein Endothelial Cells/drug effects , Morpholines/pharmacology , Neovascularization, Physiologic/drug effects , Osteosarcoma/drug therapy , Purines/pharmacology , Smad Proteins/metabolism , Animals , Bone Morphogenetic Proteins/genetics , Bone Neoplasms/metabolism , Bone Neoplasms/pathology , Cell Line, Tumor , Chick Embryo , G1 Phase Cell Cycle Checkpoints/drug effects , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Osteosarcoma/metabolism , Osteosarcoma/pathology , Signal Transduction , Smad Proteins/genetics , Smad1 Protein/metabolism , Smad2 Protein/metabolism , Smad3 Protein/metabolism
5.
Angew Chem Int Ed Engl ; 60(5): 2424-2430, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-33067864

ABSTRACT

Gold does not react with H2 to form bulk hydrides. Here we report the synthesis and characterization of a gold nanohydride protected by diphosphine ligands, [Au22 H4 (dppo)6 ]2+ [dppo=1,8-bis(diphenylphosphino)octane]. The Au22 core consists of two Au11 units bonded by eight Au atoms not coordinated by the diphosphine ligands. The four H atoms are found to bridge the eight uncoordinated Au atoms at the interface. Each Au11 unit can be viewed as a tetravalent superatom forming four delocalized Au-H-Au bonds, similar to the quadruple bond first discovered in the [Re2 Cl8 ]2- inorganic cluster. The [Au22 H4 (dppo)6 ]2+ nanohydride is found to lose H atoms over an extended time via H evolution (H2 ), proton (H+ ) and hydride (H- ) releases. This complete repertoire of H-related transformations suggests that the [Au22 H4 (dppo)6 ]2+ nanohydride is a versatile model catalyst for understanding the mechanisms of chemical reactions involving hydrogen on the surface of gold nanoparticles.

6.
Opt Express ; 28(13): 18742-18749, 2020 Jun 22.
Article in English | MEDLINE | ID: mdl-32672168

ABSTRACT

Applying multiple physical fields to artificial manipulate electromagnetic waves is a highly stirring research. In this paper, we creatively combine light control with microwave scattering, realizing an optically coding metasurface for beam deflection based on anomalous reflection. A photoresistor and a voltage-driven module are connected to control each row of PIN-diode-loaded unit cells, endowing the reflection phase of the elements with a strong dependence on light. Owing to the high sensitivity of photoresistor, the digital element state "0" or "1" can be switched effectively via light variation sensed by the photoresistor. By modulating the light signal, the arrangement of digital elements can be reprogrammed, generating the specific scattering field. Therefore, the electromagnetic field can be determined by the spatial distribution of light, which induces the connect with the optical information and microwave field. The simulated and experimental results demonstrate the feasibility of our design. This light-steering approach provides a dimension for electromagnetic wave modulation.

7.
Drug Dev Res ; 81(8): 1037-1047, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32754990

ABSTRACT

In this study, a series of new flavones (2-phenyl-chromone), 2-naphthyl chromone, 2-anthryl-chromone, or 2-biphenyl-chromone derivatives containing 6 or 7-substituted tertiary amine side chain were designed, synthesized, and evaluated in acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition. The results indicated that the alteration of aromatic ring connecting to chromone scaffold brings about a significant impact on biological activity. Compared with flavones, the inhibitory activity of 2-naphthyl chromone, 2-anthryl-chromone derivatives against AChE significantly decreased, while that of 2-biphenyl chromone derivatives with 7-substituted tertiary amine side chain is better than relative flavones derivatives. For all new synthesized compounds, the position of tertiary amine side chain obviously influenced the activity of inhibiting AChE. The results above provide great worthy information for the further development of new AChE inhibitors. Among the newly synthesized compounds, compound 5a is potent in AChE inhibition (IC50 = 1.29 ± 0.10 µmol/L) with high selectivity for AChE over BChE (selectivity ratio: 27.96). An enzyme kinetic study of compound 5a suggests that it produces a mixed-type inhibitory effect against AChE.

8.
Acc Chem Res ; 51(9): 2159-2168, 2018 09 18.
Article in English | MEDLINE | ID: mdl-30070827

ABSTRACT

A long-standing objective of cluster science is to discover highly stable clusters and to use them as models for catalysts and building blocks for cluster-assembled materials. The discovery of catalytic properties of gold nanoparticles (AuNPs) has stimulated wide interests in gaseous size-selected gold clusters. Ligand-protected AuNPs have also been extensively investigated to probe their size-dependent catalytic and optical properties. However, the need to remove ligands can introduce uncertainties in both the structures and sizes of ligand-protected AuNPs for catalytic applications. Ideal model catalysts should be atomically precise AuNPs with well-defined structures and uncoordinated surface sites as in situ active centers. The tetrahedral ( Td) Au20 pyramidal cluster, discovered to be highly stable in the gas phase, provided a unique opportunity for such an ideal model system. The Td-Au20 consists of four Au(111) faces with all its atoms on the surface. Bulk synthesis of Td-Au20 with appropriate ligands would allow its catalytic and optical properties to be investigated and harnessed. The different types of its surface atoms would allow site-specific chemistry to be exploited. It was hypothesized that if the four corner atoms of Td-Au20 were coordinated by ligands the cluster would still contain 16 uncoordinated surface sites as potential in situ catalytically active centers. Phosphine ligands were deemed to be suitable for the synthesis of Td-Au20 to maintain the integrity of its pyramidal structure. Triphenyl-phosphine-protected Td-Au20 was first observed in solution, and its stability was confirmed both experimentally and theoretically. To enhance the synthetic yield, bidentate diphosphine ligands [(Ph)2P(CH2) nP(Ph)2 or L n] with different chain lengths were explored. It was hypothesized that diphosphine ligands with the right chain length might preferentially coordinate to the Td-Au20. Promising evidence was initially obtained by the formation of the undecagold by the L3 ligand. When the L8 diphosphine ligand was used, a remarkable Au22 nanocluster with eight uncoordinated Au sites, Au22(L8)6, was synthesized. With a tetraphosphine-ligand (PP3), a new Au20 nanocluster, [Au20(PP3)4]Cl4, was isolated with high yield. The crystal structure of the new Au20 core did not reveal the expected pyramid but rather an intrinsically chiral gold core. The surface of the new chiral-Au20 was fully coordinated, and it was found to be highly stable chemically. The Au22(L8)6 nanocluster represents the first and only gold core with uncoordinated gold atoms, providing potentially eight in situ catalytically active sites. The Au22 nanoclusters dispersed on oxide supports were found to catalyze CO oxidation and activate H2 without ligand removal. With further understanding about the formation mechanisms of gold nanoclusters in solution, it is conceivable that Td-Au20 can be eventually synthesized, allowing its novel catalytic and optical properties to be explored. More excitingly, it is possible that a whole family of new atomically precise gold nanoclusters can be created with different phosphine ligands.

9.
Phys Chem Chem Phys ; 21(28): 15541-15550, 2019 Jul 17.
Article in English | MEDLINE | ID: mdl-31264677

ABSTRACT

The capture and separation of CO2 have attracted significant interest as a strategy to control the global emission of greenhouse gases. From the perspective of environmental protection, it is crucial to explore high-performance adsorbents that can efficiently capture CO2. Herein, we report a density functional theory study on the viability of the heteroborospherene C4B32 for the first time. C2v C4B32 was revealed to be a perfect cubic heteroborospherene with the HOMO-LUMO gap of 3.47 eV at the PBE0 level. Then, we evaluated the potential application of C4B32 in the capture and separation of CO2. Our results indicate that the cubic-like C4B32 can efficiently capture CO2 with a -1.34 eV adsorption energy via chemisorption at the most acidic and basic sites of the cage. The strong interaction between CO2 and C4B32 could be supported by an effective charge transfer and orbital overlap. C4B32 also displayed high selectivity for the separation of CO2 from NH3, N2, CH4, CO, and H2 mixtures. Furthermore, it was feasible to tune the CO2-capture ability of C4B32 by metal-doping, which regulated the Lewis acidity/basicity of the C4B32 surface. In particular, Ca-doping could significantly enhance the CO2-capture ability of C4B32. Our results show that as a highly symmetrical and stable heteroborospherene, C4B32 can be used as a building block for the design and synthesis of novel nanomaterials for the capture and separation of CO2.

10.
J Am Chem Soc ; 140(21): 6718-6726, 2018 05 30.
Article in English | MEDLINE | ID: mdl-29732884

ABSTRACT

Boron compounds are well-known electrophiles. Much less known are their nucleophilic properties. By recognition of the nucleophilicity of the B-H bond, the formation mechanism of octahydrotriborate (B3H8-) was elucidated on the bases of both experimental and computational investigations. Two possible routes from the reaction of BH4- and THF·BH3 to B3H8- were proposed, both involving the B2H6 and BH4- intermediates. The two pathways consist of a set of complicated intermediates, which can convert to each other reversibly at room temperature and can be represented by a reaction circle. Only under reflux can the B2H6 and BH4- intermediates be converted to B2H5- and BH3(H2) via a high energy barrier, from which H2 elimination occurs to yield the B3H8- final product. The formation of B2H6 from THF·BH3 by nucleophilic substitution of the B-H bond was captured and identified, and the reaction of B2H6 with BH4- to produce B3H8- was confirmed experimentally. On the bases of the formation mechanisms of B3H8-, we have developed a facile synthetic method for MB3H8 (M = Li and Na) in high yields by directly reacting the corresponding MBH4 salts with THF·BH3. In the new synthetic method for MB3H8, no electron carriers are needed, allowing convenient preparation of MB3H8 in large scales and paving the way for their wide applications.

11.
Nano Lett ; 16(10): 6560-6567, 2016 Oct 12.
Article in English | MEDLINE | ID: mdl-27685318

ABSTRACT

Investigation of atomically precise Au nanoclusters provides a route to understand the roles of coordination, size, and ligand effects on Au catalysis. Herein, we explored the catalytic behavior of a newly synthesized Au22(L8)6 nanocluster (L = 1,8-bis(diphenylphosphino) octane) with in situ uncoordinated Au sites supported on TiO2, CeO2, and Al2O3. Stability of the supported Au22 nanoclusters was probed structurally by in situ extended X-ray absorption fine structure (EXAFS) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and their ability to adsorb and oxidize CO was investigated by IR absorption spectroscopy and a temperature-programmed flow reaction. Low-temperature CO oxidation activity was observed for the supported pristine Au22(L8)6 nanoclusters without ligand removal. Density functional theory (DFT) calculations confirmed that the eight uncoordinated Au sites in the intact Au22(L8)6 nanoclusters can chemisorb both CO and O2. Use of isotopically labeled O2 demonstrated that the reaction pathway occurs mainly through a redox mechanism, consistent with the observed support-dependent activity trend of CeO2 > TiO2 > Al2O3. We conclude that the uncoordinated Au sites in the intact Au22(L8)6 nanoclusters are capable of adsorbing CO, activating O2, and catalyzing CO oxidation reaction. This work is the first clear demonstration of a ligand-protected intact Au nanocluster that is active for gas-phase catalysis without the need of ligand removal.

12.
Small ; 12(18): 2518-25, 2016 May.
Article in English | MEDLINE | ID: mdl-27007493

ABSTRACT

A new Au22 nanocluster, protected by bis(2-diphenyl-phosphino)ethyl ether (dppee or C28 H28 OP2 ) ligand, has been synthsized and purified with high yield. Electrospray mass spectrometry shows that the new cluster has a formula of Au22 (dppee)7 , containing 22 gold atoms and seven dppee ligands. The cluster is found to be stable as a solid, but metastable in solution. The new cluster has been characterized by UV-Vis-NIR absorption spectroscopy, collision-induced dissociation, and (31) P-NMR. The properties of the new cluster have been compared with the previous Au22 (dppo)6 nanocluster (dppo = 1,8-bis(diphenyl-phosphino)octane or C32 H36 P2 ), which contains two fused Au11 units. All the experimental data indicate that the new Au22 (dppee)7 cluster is different from the previously known Au22 (dppo)6 cluster and represents a new Au22 core, which contains most likely one Au11 motif with several Au2 (dppee) or Au(dppee) units. The Au22 (dppee)7 cluster provides a new example of the ligand effects on the nuclearity and structural polymorphism of phosphine-protected atom-precise gold nanoclusters.

13.
Org Biomol Chem ; 14(29): 6937-41, 2016 Aug 07.
Article in English | MEDLINE | ID: mdl-27345438

ABSTRACT

A chiral phosphoric acid-catalyzed asymmetric transfer hydrogenation of 3-trifluoromethylthioquinolines has been successfully developed, providing direct and facile access to chiral 2,3-disubstituted 1,2,3,4-tetrahydroquinoline derivatives containing a stereogenic trifluoromethylthio group with up to 99% enantioselectivity.

14.
Nucleic Acids Res ; 41(Database issue): D1115-23, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23161677

ABSTRACT

The G-quadruplex ligands database (G4LDB, http://www.g4ldb.org) provides a unique collection of reported G-quadruplex ligands to streamline ligand/drug discovery targeting G-quadruplexes. G-quadruplexes are guanine-rich nucleic acid sequences in human telomeres and gene promoter regions. There is a growing recognition for their profound roles in a wide spectrum of diseases, such as cancer, diabetes and cardiovascular disease. Ligands that affect the structure and activity of G-quadruplexes can shed light on the search for G-quadruplex-targeting drugs. Therefore, we built the G4LDB to (i) compile a data set covering various physical properties and 3D structure of G-quadruplex ligands; (ii) provide Web-based tools for G-quadruplex ligand design; and (iii) to facilitate the discovery of novel therapeutic and diagnostic agents targeting G-quadruplexes. G4LDB currently contains >800 G-quadruplex ligands with ∼4000 activity records, which, to our knowledge, is the most extensive collection of its kind. It offers a user friendly interface that can meet a variety of data inquiries from researchers. For example, ligands can be searched for by name, molecular properties, structures, ligand activities and so on. Building on the reported data, the database also provides an online ligand design module that can predict ligand binding affinity in real time.


Subject(s)
Databases, Chemical , Drug Design , G-Quadruplexes/drug effects , Internet , Ligands , Molecular Docking Simulation
15.
Luminescence ; 30(8): 1176-83, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25736560

ABSTRACT

Complexation between the primary carrier of ligands in blood plasma, human serum transferrin (Tf), and a cyanine dye, 3,3'-di(3-sulfopropyl)-4,5,4',5'-dibenzo-9-phenyl-thiacarbocyanine-triethylam monium salt (PTC) was investigated using fluorescence spectra, UV/Vis absorption spectra, synchronous fluorescence spectra, circular dichroism (CD) and molecular dynamic docking. The experimental results demonstrate that the formation of PTC-Tf complex is stabilized by van der Waal's interactions and hydrogen bonds, and the binding constants were found to be 8.55 × 10(6), 8.19 × 10(6) and 1.75 × 10(4) M(-1). Moreover, fluorescence experiments prove that the operational mechanism for the fluorescence quenching is static quenching and non-radiative energy transfer. Structural investigation of the PTC-Tf complexes via synchronous fluorescence spectra and CD showed that the structure of Tf became more stable with a major increase in the α-helix content and increased polarity around the tryptophan residues after PTC binding. In addition, molecular modeling highlights the residues located in the N-lobe, which retain high affinity for PTC. The mode of action of the PTC-Tf complex is illustrated by these results, and may provide an effective pathway for the transport and targeted delivery of antitumor agents.


Subject(s)
Carbocyanines/chemistry , Coloring Agents/chemistry , Transferrin/chemistry , Fluorescence , Humans , Kinetics , Protein Binding , Protein Structure, Secondary , Spectrometry, Fluorescence
16.
J Am Chem Soc ; 136(1): 92-5, 2014 Jan 08.
Article in English | MEDLINE | ID: mdl-24351099

ABSTRACT

We report the synthesis and structure determination of a new Au22 nanocluster coordinated by six bidentate diphosphine ligands: 1,8-bis(diphenylphosphino) octane (L(8) for short). Single crystal X-ray crystallography and electrospray ionization mass spectrometry show that the cluster assembly is neutral and can be formulated as Au22(L(8))6. The Au22 core consists of two Au11 units clipped together by four L(8) ligands, while the additional two ligands coordinate to each Au11 unit in a bidentate fashion. Eight gold atoms at the interface of the two Au11 units are not coordinated by any ligands. Four short gold-gold distances (2.64-2.65 Å) are observed at the interface of the two Au11 clusters as a result of the clamping force of the four clipping ligands and strong electronic interactions. The eight uncoordinated surface gold atoms in the Au22(L(8))6 nanocluster are unprecedented in atom-precise gold nanoparticles and can be considered as potential in situ active sites for catalysis.


Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Phosphines/chemistry , Crystallography, X-Ray , Ligands , Mass Spectrometry , Models, Molecular
17.
Electrophoresis ; 35(5): 762-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24114803

ABSTRACT

This paper proposes a novel strategy to enhance detection of doxorubicin in human plasma, using homemade CE combined with normal stacking mode (NSM). The detection system of CE named as in-column tapered optic-fiber light-emitting diode induced fluorescence detection system is economic and more sensitive that has been demonstrated in our previous work. The influence of sample matrix, BGE, applied voltage, and injection time on the efficiency of NSM were systematically investigated. The clean extracts were subjected to CE separation with optimal experimental conditions: Ethanol-water (1:1, v/v) was used as sample matrix, pH 4.12 15 mM sodium phosphate buffer solution containing 70% v/v ACN, applied voltage 23 kV and 45 s hydrodynamic injection at a height of 20 cm. The detection system displayed linear dynamic range from 6.4 to 1.13 × 10(3) ng/mL with a correlation coefficient of 0.9990 and LOD 2.2 ng/mL for doxorubicin (DOX). The proposed CE method has been successfully applied to determine DOX in human plasma which the recoveries of standard DOX added to human plasma were found to been the range of 93.8-104.6%. The results obtained demonstrate that our detection system combined with NSM is a good idea to enhance sensitivity in CE for routine determination of DOX in some biological specimens.


Subject(s)
Doxorubicin/blood , Electrophoresis, Capillary/methods , Spectrometry, Fluorescence/instrumentation , Spectrometry, Fluorescence/methods , Buffers , Equipment Design , Ethanol , Humans , Optical Fibers , Reproducibility of Results
18.
Inorg Chem ; 53(8): 3932-4, 2014 Apr 21.
Article in English | MEDLINE | ID: mdl-24684605

ABSTRACT

We report the synthesis and structure determination of a new Au20 nanocluster coordinated by four tripodal tetraphosphine (PP3) ligands {PP3 = tris[2-(diphenylphosphino)ethyl]phosphine}. Single-crystal X-ray crystallography and electrospray ionization mass spectrometry show that the cluster assembly can be formulated as [Au20(PP3)4]Cl4. The Au20 cluster consists of an icosahedral Au13 core and a seven-Au-atom partial outer shell arranged in a local C3 symmetry. One PP3 ligand coordinates to four Au atoms in the outer shell, while the other three PP3 ligands coordinate to one Au atom from the outer shell and three Au atoms from the surface of the Au13 core, giving rise to an overall chiral 16-electron Au cluster core with C3 symmetry.

19.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(11): 3045-50, 2014 Nov.
Article in Zh | MEDLINE | ID: mdl-25752055

ABSTRACT

Using cyanine dyes supramolecular as molecular probes to mark FA has important significance in life sciences and pharmaceutical chemistry, which can detect FA as drug efficacy mechanism and the change in physiological activity. In the present paper, we investigated supramolecular assembly and chiral inducement of cyanine dyes template by FA with absorption and circular dichroism (CD) spectra. The result suggests that FA can induce cyanine dyes from J-aggregation to monomer along with different colors change and has strong affinity with cyanine dye monomer. The template of FA not only can translate the chirality of MTC H-aggregation to other two states, but also induce ETC J-aggregation to molecular rearrangement and form left-handed helix of J-aggregates. Besides, the association of PTC with FA, i. e. binding to FA gave rise to the J-aggregation CD signals. Meanwhile, it was inferred that the meso substituent of cyanine dyes play an important role in the interaction between FA and the J-aggregation: the smaller the meso substituent, the higher the affinity interacted with FA. Clearly, the binding abilities between cyanine dyes and FA follow the order of MTC>ETC>PTC. These results support that the cyanine dyes supramolecular aggregates can be used as a kind of excellent molecular probes for specific recognition of FA and achieve the effect of visual inspection.


Subject(s)
Benzopyrans/chemistry , Carbocyanines/chemistry , Coloring Agents/chemistry , Circular Dichroism , Macromolecular Substances
20.
Sci Rep ; 14(1): 20136, 2024 08 29.
Article in English | MEDLINE | ID: mdl-39209899

ABSTRACT

Pregestational diabetes mellitus (PGDM) has an impact on fetal bone formation, but the underlying mechanism is still obscure. Although miRNAs have been extensively investigated throughout bone formation, their effects on fetal bone development caused by PGDM still need clarification. This study intends to examine the mechanism by which hyperglycemia impairs the bone formation of offspring via miR-322-5p (miR-322). In this study, miR-322 was selected by systemically screening utilizing bioinformatics and subsequent validation experiments. Using streptozotocin (STZ)-induced diabetic mice and ATDC5 cell lines, we found that miR-322 was abundantly expressed in the proliferative and hypertrophic zones of the growth plate, and its expression pattern was disturbed in the presence of hyperglycemia, suggesting that miR-322 is involved in the chondrocyte proliferation and differentiation in absence/presence of hyperglycemia. This observation was proved by manipulating miR-322 expression in ATDC5 cells by transfecting mimic and inhibitor of miR-322. Furthermore, Adamts5, Col12a1, and Cbx6 were identified as the potential target genes of miR-322, verified by the co-transfection of miR-322 inhibitor and the siRNAs, respectively. The evaluation criteria are the chondrocyte proliferation and differentiation and their relevant key gene expressions (proliferation: Sox9 and PthIh; differentiation: Runx2 and Col10a1) after manipulating the gene expressions in ATDC5 cells. This study revealed the regulative role miR-322 on chondrocyte proliferation and differentiation of growth plate by targeting Adamts5, Col12a1, and Cbx6 in hyperglycemia during pregnancy. This translational potential represents a promising avenue for advancing our understanding of bone-related complications in diabetic pregnancy and mitigating bone deficiencies in diabetic pregnant individuals, improving maternal and fetal outcomes.


Subject(s)
Cell Differentiation , Cell Proliferation , Chondrocytes , Diabetes Mellitus, Experimental , Diabetes, Gestational , Growth Plate , MicroRNAs , Animals , Female , Mice , Pregnancy , Cell Differentiation/genetics , Cell Line , Cell Proliferation/genetics , Chondrocytes/metabolism , Chondrocytes/pathology , Diabetes Mellitus, Experimental/genetics , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Diabetes, Gestational/metabolism , Diabetes, Gestational/genetics , Diabetes, Gestational/pathology , Growth Plate/metabolism , Growth Plate/pathology , MicroRNAs/genetics , MicroRNAs/metabolism
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