A readily accessible multifunctional probe: simultaneous recognition of the cation ZN²⁺ and the anion F⁻ via distinguishable wavelengths

The probe 1 was readily prepared via condensation of 8-formyl-7-hydroxy-coumarin and carbonic dihydrazide in a one-step procedure. Probe 1 exhibited high sensitivity and selectivity towards Zn²⁺ and F⁻ through a “turn-on” fluorescence response and/or ratiometric colorimetric response with low detection limits of the order of 10-8 M. The complex behaviour was fully investigated by spectral titration, isothermal titration calorimetry, 1H NMR spectroscopic titration and mass spectrometry. Interestingly, probe 1 not only recognizes the cation Zn²⁺ and the anion F⁻, but can also distinguish between these two ions via the max wavelength in their UV-vis spectra (360 nm for 1-Zn²⁺ versus 400 nm for 1-F⁻ complex) or their fluorescent spectra (λₑₓ / λₑm = 360 nm/ 454 nm for 1-Zn²⁺ versus λₑₓ / λₑm = 400 nm/ 475 nm for 1-F⁻ complex) due to their differing red-shifts. Additionally, probe 1 has been further explored in the detection of Zn²⁺ in living cells

Targeting immune checkpoints in anti-neutrophil cytoplasmic antibodies associated vasculitis: the potential therapeutic targets in the future

Anti-neutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) is a necrotizing vasculitis mainly involving small blood vessels. It is demonstrated that T cells are important in the pathogenesis of AAV, including regulatory T cells (Treg) and helper T cells (Th), especially Th2, Th17, and follicular Th cells (Tfh). In addition, the exhaustion of T cells predicted the favorable prognosis of AAV. The immune checkpoints (ICs) consist of a group of co-stimulatory and co-inhibitory molecules expressed on the surface of T cells, which maintains a balance between the activation and exhaustion of T cells. CD28, inducible T-cell co-stimulator (ICOS), OX40, CD40L, glucocorticoid induced tumor necrosis factor receptor (GITR), and CD137 are the common co-stimulatory molecules, while the programmed cell death 1 (PD-1), cytotoxic T lymphocyte-associated molecule 4 (CTLA-4), T cell immunoglobulin (Ig) and mucin domain-containing protein 3 (TIM-3), B and T lymphocyte attenuator (BTLA), V-domain Ig suppressor of T cell activation (VISTA), T-cell Ig and ITIM domain (TIGIT), CD200, and lymphocyte activation gene 3 (LAG-3) belong to co-inhibitory molecules. If this balance was disrupted and the activation of T cells was increased, autoimmune diseases (AIDs) might be induced. Even in the treatment of malignant tumors, activation of T cells by immune checkpoint inhibitors (ICIs) may result in AIDs known as rheumatic immune-related adverse events (Rh-irAEs), suggesting the importance of ICs in AIDs. In this review, we summarized the features of AAV induced by immunotherapy using ICIs in patients with malignant tumors, and then reviewed the biological characteristics of different ICs. Our aim was to explore potential targets in ICs for future treatment of AAV

Azadiradione exerts anti-inflammatory and anti-oxidant effects, alleviates dopaminergic neurodegeneration and reduces α-synuclein levels in MPTP-induced mouse model of Parkinson’s disease

Purpose: To determine the effects of azadiradione (AZD), a tetracyclic triterpenoid, in 1-methyl-4- phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)–induced experimental rodent model of Parkinson’s disease (PD). Methods: C57BL/6 mice were intraperitoneally injected MPTP at a dose of 20 mg/kg body weight in saline (4 times at 2-h intervals). Azadiradione (AZD) at doses of 12.5, 25 or 50 mg/kg were administered to separate groups of mice via oral gavage for 6 days prior to MPTP injection. Results: Azadiradione (AZD) reduced loss of tyrosine hydroxylase (TH)-positive neurons. TH-positive counts increased to 91.44 % on treatment with 50 mg/kg AZD. Significantly (p < 0.05) down-regulated α-synuclein levels were seen following MPTP induction and AZD administration. Expressions of Bax, Bcl-2 and cleaved-caspase-3 were significantly downregulated (p < 0.05). Treatment with AZD inhibited the translocation of Cyt-C to the mitochondria, thereby preventing activation of apoptotic cascade. Oxidative stress induced by MPTP was significantly reduced by AZD via up-regulation of glutathione levels and SOD1/HO-1 expression. Azadiradione, at a dose of 50 mg/kg, significantly (p < 0.05) reduced ROS levels from 210.6 19.23%, and also reduced the levels of inflammatory cytokines. Conclusion: These results indicate the anti-inflammatory, anti-oxidative and neuroprotective properties of AZD in mice. Thus, AZD is a potential candidate drug for the management of PD. However, further studies are required to ascertain this

Ag-Cu nanoalloyed film as a high-performance cathode electrocatalytic material for zinc-air battery

Abstract A novel Ag50Cu50 film electrocatalyst for oxygen reduction reaction (ORR) was prepared by pulsed laser deposition (PLD) method. The electrocatalyst actually is Ag-Cu alloyed nanoparticles embedded in amorphous Cu film, based on transmission electron microscopy (TEM) characterization. The rotating disk electrode (RDE) measurements provide evidence that the ORR proceed via a four-electron pathway on the electrocatalysts in alkaline solution. And it is much more efficient than pure Ag catalyst. The catalytic layer has maximum power density of 67 mW cm−2 and an acceptable cell voltage at 0.863 V when current densities increased up to 100 mA cm−2 in the Ag50Cu50-based primary zinc-air battery. The resulting rechargeable zinc-air battery exhibits low charge-discharge voltage polarization of 1.1 V at 20 mAcm−2 and high durability over 100 cycles in natural air.</jats:p

Highly selective recognition of Al3+ and I- ions using a bifunctional fluorescent probe

A tripodal fluorescent probe L1 armed with rhodamine B and 1-naphthaleneisothiocyanates was prepared in high yield. A study of the recognition properties revealed that probe L1 exhibited high sensitivity and selectivity towards Al3⁺ through a “FRET” fluorescence response and colorimetric response with low detection limits of the order of 10-8 M. Meanwhile, probe L1 also possessed high recognition capability for I⁻ through fluorescent decay, which given there are comparatively few selective fluorescent probes for I⁻, is significant. Furthermore, the complexation mechanisms were fully investigated by spectral titrations, 1H NMR spectroscopic titrations and mass spectrometry. The utility of probe L1 as a biosensor in living cells (PC3 cells) towards Al3⁺ ions has also been demonstrated

A 2-Styryl-1,8-naphthyridine derivative as a versatile fluorescent probe for the selective recognition of Hg²⁺, Ag⁺ and F⁻ ions by tuning the solvent

A novel fluorescent probe 1 has been synthesized by a microwave reaction, and its ion-binding and fluorescence-sensing properties have been investigated under different solvent conditions. The analysis results indicated that probe 1 can act as a multiple analysis probe by simply tuning the solvent. Probe 1 exhibited high selectively toward Hg²⁺ through fluorescence quenching in H₂O/DMF. In H₂O/1,4-dioxane solution, probe 1 selectively recognized and discriminated between Ag⁺ and Hg²⁺ displaying ratiometric behaviour. Moreover, probe 1 readily recognized the anion F⁻ via the ratiometric fluorescent mode in CH3CN. Furthermore, distinct colour changes were observed under UV light, which can be seen by the naked eye and thus used for distinguishing Hg²⁺, Ag+ and F⁻ from the other ions screened herein using probe 1. Interestingly, almost pure white light emission was evident by simply tuning the F⁻ anion-concentration, which makes this system a potential candidate for smart and tunable luminescent materials

A multifunctional tripodal fluorescent probe for the recognition of Cr3+, Al3+, Zn2+ and F− with controllable ESIPT processes

Three 4-(benzo[d]thiazol-2-yl)-2,5-dihydroxybenzaldehyde fluorophores were introduced to construct a tripodal multifunctional ESPIT fluorescence probe L. The fluorescent analysis revealed that probe L exhibited excellent recognition capabilities towards Cr3+, Al3+, Zn2+ and F− ions with large Stokes shifts. Furthermore, under optimal conditions, the detection limit of probe L towards Cr3+, Al3+, Zn2+ and F− were low, of the order of 10−8 M, which indicated that probe L was sensitive to these four ions. Interestingly, the fluorescent and 1H NMR titration experiments revealed that the recognition mechanism of probe L towards the ions Cr3+, Al3+, Zn2+ and F− were different. The presence of Cr3+ and Al3+ recovered the ESIPT, but the presence of Zn2+ trigger a moderate deprotonation of the phenolic OH and induced an ESIPT red-shifted (60 nm) emission wavelength. Finally, the presence of F− completely deprotonated the free phenolic OH and a remarkable red-shifted (130 nm) ESIPT emission was observed. In other words, the ESIPT process of probe L is controllable. Furthermore, the utility of probe L as a biosensor in living cells (PC3 cells) towards Cr3+, Al3+ and Zn2+ ions has been demonstrated

Molecular Tweezers-like Calix[4]arene Based Alkaline Earth Metal Cation (Ca2+, Sr2+, and Ba2+) Chemosensor and Its Imaging in Living Cells and Zebrafish

Although alkaline earth metal cations play an important role in our daily life, little attention has been paid to the field of fast quantitative analysis of their content due to a lack of satisfactory precision and a fast and convenient means of detection. In this study, we have designed a set of molecular tweezers based on the calix[4]arene chemosensor L, which was found to exhibit high selectivity and sensitivity toward Ca2+, Sr2+, and Ba2+ (by UV-vis and fluorescence methods) with low detection limits of the order of 10-7 to 10-8 M and high association constants (of the order of 106). More significantly, sensor L not only can recognize Ca2+, Sr2+, and Ba2+ but also can further discriminate between these three cations via the differing red shifts in their UV-vis spectra (560 nm for L·Ca2+, 570 nm for L·Sr2+, and 580 nm for L·Ba2+ complex) which is attributed to their different atomic radii. A rare synergistic effect for the recognition mechanism has been demonstrated by 1H NMR spectroscopic titration. Sensor L constructed a high shielding field by the cooperation of Tris with alkaline earth metal ion after complex. Additionally, the presence of acetoxymethyl group in sensor L results in enhancement of cell permeability, and as a consequence, sensor L exhibited excellent sensing and imaging (in vivo) in living cells and in zebrafish

형광공명에너지전달을 이용한 수모일레이션반응의 탐지

학위논문(석사) - 한국과학기술원 : 생명과학과, 2005.2, [ v, 30 p. ]The primary goal of this research is to examine feasibility of the application of FRET detection method in SUMOylation detection. SUMOylation is one of recently discovered post-translational modification processes, which is adopted by eukaryotic cells to control various important cellular functions. This study is based on the fact that SUMO1(G) as SUMOylation modifier, after SUMOylation would covalently attach to it’s SUMOylation substrates. Human RanGAP1 domain containing SUMOylation motif was used as a model. ECFP fusion human SUMO1(G) was used as modifier and EYFP fusion human RanGAP1 domain as its substrate. Since the constant attachment between this two proteins，in short proximity, fluorescence resonance energy transfer(FRET) might occur between donor ECFP and acceptor EYFP, result in increased fluorescence intensity at EYFP emission region under 400nm ECFP excitation that normally not occur in negative control. As result, FRET occurrence was confirmed by obvious changes in increased fluorescence emission in the emission region of EYFP(510nm~530nm) after background reducing process by membrane filtration. The result enables further application of FRET method in the study of in vivo SUMOylation dynamics, or in combination with high throughput SUMO target screening system.한국과학기술원 : 생명과학과