A spiropyran functionalized fluorescent probe for mitochondria targeting and imaging of endogenous hydrogen sulfide in living cells.

A turn-on spiropyran functionalized fluorescein derivative (FMC) is developed for targeting HS- in mitochondria. FMC exhibits very weak fluorescence at 525 nm under the excitation of 470 nm in aqueous solution due to its colorless spiropyran form; upon addition of HS-, a strong fluorescence enhancement by 6.4-fold is observed with spirocycle-opened merocyanine form and rapid trapping kinetics for HS-. FMC has good biocompatibility and high selectivity towards HS- with a detection limit of 88.2 nM and is very sensitive among the reported H2S fluorescent probes. Moreover, the significant colocalization of FMC with Mito Tracker® Deep Red FM in human laryngeal epidermoid carcinoma (HEp-2) cells and the Pearson correlation coefficient of 0.87 together demonstrate that FMC can target and image the endogenous H2S in the mitochondria of living cells.

One-Pot Synthesis of Indoles by a Sequential Ugi-3CR/Wittig Reaction Starting from Odorless Isocyanide-Substituted Phosphonium Salts.

A new one-pot preparation of indoles by a Ugi-3CR/Wittig sequence has been developed. The reaction of odorless isocyanide-substituted phosphonium salt 5, aldehyde 6, and amine 7 produced the indoles 9 in 45-82% yields via a sequential Ugi-3CR/Wittig reaction in the presence of H3PO4 and solid K2CO3, respectively.

One-Pot Synthesis of Multisubstituted Benzimidazoles via Sequential Ugi and Catalytic Aza-Wittig Reaction Starting from 2-Aminobenzoyl Azides.

A simple and one-pot synthesis of multisubstituted benzimidazoles by a Ugi 4CC/catalytic aza-Wittig sequence was developed. The reaction of 2-aminobenzoyl azide 2, aldehyde 3, acid 4, and isocyanide 5 produced the benzimidazoles 8 in moderate to good yields via a sequential Ugi condensation and catalytic aza-Wittig in the presence of a catalytic amount of phospholene oxide.

Highly Selective Coextraction of H+/SO42- Using a Strapped Calix[4]pyrrole.

We report on the synthesis of a cage-type calix[4]pyrrole (1) bearing an additional basic pyridinebisthiazolamine group on the strap. The receptor in its protonated form shows strong affinity and selectivity for sulfate over a wide range of inorganic anions. With receptor 1 as a liquid-liquid extractant, H+/SO42- in the form of H2SO4 is almost quantitatively extracted from an aqueous solution containing HNO3 at a high concentration to CH2Cl2 in a recyclable manner.

Nitrogen-doped carbon dots for sensitive detection of ferric ions and monohydrogen phosphate by the naked eye and imaging in living cells.

Nitrogen doped carbon dots (N-CDs) have been prepared via a one-pot hydrothermal method by using formamide and o-phenylenediamine as the carbon precursors. The as-fabricated N-CDs display excellent water dispersibility, good biocompatibility and anti-photobleaching properties. A strong emission band with an emission maximum (λ fl max) of 556 nm is observed under 450 nm excitation, and a large Stokes shift of 106 nm is presented. However, the fluorescence is quenched by the addition of Fe3+; a good linearity is shown in the range of 0-65 µM with a detection limit as low as 0.85 µM. Fortunately, the quenched fluorescence could be recovered rapidly by the addition of monohydrogen phosphate (HPO4 2-) due to the formation of the stable [N-CDs-Fe3+-HPO4 2-] complex, and a good linearity is exhibited in the range of 0-60 µM with a low detection limit of 0.80 µM for HPO4 2-. A novel "on-off-on" fluorescence response is seen with an obvious color change from yellow-crimson-yellow by the naked eye. In addition, the confocal microscopy images suggest that the as-synthesized N-CDs could serve as a sensitive nanosensor for Fe3+ and HPO4 2- detection, implying the diverse potential application of N-CDs in the biomedical field.

Benzenebistriazole-strapped calix[4]pyrrole: a neutral anion receptor with CH and NH donor groups that exhibits high sulfate binding affinity and selectivity in aqueous solutions.

A calix[4]pyrrole strapped by benzenebistriazole has been prepared as an artificial anion binding receptor. This neutral anion receptor shows high sulfate binding affinity and selectivity in an aqueous solution. In solid state, the receptor binds the sulfate anion in a chair-like 3D cavity via multiple N-H and C-H hydrogen bonds.

1,25-dihydroxyvitamin-D3 promotes neutrophil apoptosis in periodontitis with type 2 diabetes mellitus patients via the p38/MAPK pathway.

BACKGROUND: Abnormal neutrophils are involved in many chronic endocrine diseases, including type 2 diabetes mellitus (T2DM), and in periodontitis (PD), which is a chronic inflammatory disease in which neutrophils play a vital role. The p38 mitogen-activated protein kinase (MAPK) signaling pathway participates in the apoptosis of many inflammatory cells. Additionally, 1,25-dihydroxyvitamin-D3 (1,25VitD3) as a regulator can induce responses to infection and tumor cell apoptosis. However, the effect of 1,25VitD3 in the pathogenic relationship between T2DM and PD remains unclear. The aim of this study was to assess the effect of 1,25VitD3 on neutrophil apoptosis in patients with T2DM and PD and the p38-MAPK-relevant signaling pathway mechanism in this process in vitro. METHODS: Neutrophils were stained with Wright's stain, and apoptosis was detected by flow cytometry and Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. Apoptosis- and p38-related mRNAs and proteins were examined by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blotting and ELISA. The internal relationships were analyzed using a linear regression equation and Pearson's correlation coefficient. RESULTS: The highest rate of neutrophil apoptosis occurred in cultures treated with 10 mol/L 1,25VitD3 in the T2DM-PD group. The apoptosis rate in the T2DM-PD-p38 inhibitor group was higher than that in the healthy control group. Western blot, ELISA and qRT-PCR results showed that the mRNA and protein expression profiles of Caspase-3 and Bax were highly up-regulated and that Bcl-2 was down-regulated in the T2DM-PD-p38 inhibitor group. The expression levels of apoptotic mRNAs and proteins in the T2DM and T2DM-PD groups were significantly higher than those in the T2DM-p38 and T2DM-PD-p38 inhibitor groups. 1,25VitD3-induced neutrophil apoptosis and phosphorylated p38 (p-p38) expression were partially inhibited by the p38 inhibitor. Expression levels of apoptosis-related genes and p-p38 in neutrophils were positively associated with increasing concentrations of 1,25VitD3. p-p38 protein expression was positively associated with the level of serum 1,25VitD3. CONCLUSION: 1,25VitD3 could promote peripheral blood neutrophil apoptosis in patients with T2DM and PD through activation of the p38-MAPK signaling pathway in vitro.