A phenazine-imidazole based ratiometric fluorescent probe for Cd2+ ions and its application in in vivo imaging.

A new phenazine-imidazole based Schiff base (PIS) fluorescent probe has been developed for the ratiometric detection of Cd2+ ions in aqueous media at physiological pH. PIS upon binding with Cd2+ ions shows red shifted fluorescence and thereby, permits ratiometric detection of Cd(II) ions. A detection limit down to 2.10 × 10-8 M was determined for Cd2+ quantitation. Also, the accompanying apparent fluorescence color change (from yellow to orange red) is noticeable to the naked eye under a UV-lamp. The sensing mechanism could be attributed to the 1 : 1 PIS-Cd complexation, followed by extension of the conjugation due to better planarity and modulation of the charge transfer efficiency in the probe. This was complemented by solvatochromism and density functional theory calculations. Furthermore, PIS was used to detect Cd2+ in Oxya chinensis cells, zebrafish larvae and live tissues of Arabidopsis thaliana under a fluorescence microscope, showing great potential in analyzing living biosystems.

New colorimetric and fluorometric chemosensor for selective Hg2+ sensing in a near-perfect aqueous solution and bio-imaging.

We report a new 7-nitrobenzo-2-oxa-1, 3-diazolyl (NBD)-based chemosensor containing a piperazine derivative, NBDP, for detection of mercury ions in almost 100% aqueous medium. The chemosensor shows sensing exclusively toward Hg2+ with a switch-on fluorescence response at 543 nm, which could be attributed to the blocking of PET (photo-induced electron transfer) process upon complexation with mercury ions. The molar ratio of Hg(Ⅱ) to NBDP in the complex is 1:1 based on the Job's plot and HRMS studies. Optimized configurations of NBDP and NBDP-Hg2+ complexes were simulated by means of DFT calculations. The reversible fluorescence response with low detection limit (19.2 nM) in the pH range of 6.0-7.5 renders NBDP a promising candidate for Hg2+ detection in neutral aqueous environments. For the practical application of the chemosensor, test strips were successfully fabricated for rapid detection of Hg2+ ions. Moreover, the utility of NBDP showing the mercury recognition in Human liver cancer cells (SMMC-7721) and zebrafish as well as in live tissues of Arabidopsis thaliana has been demonstrated as monitored by fluorescence imaging.

Gastrodin protects retinal ganglion cells through inhibiting microglial-mediated neuroinflammation in an acute ocular hypertension model.

AIM: To investigate the neuroprotective effect of gastrodin on retinal ganglion cells (RGCs) in an acute ocular hypertension (AOH) rat model and to identify its possible mechanism. METHODS: AOH rat model was performed in a randomly selected eye by anterior chamber perfusion and either received an intraperitoneal injection with various concentrations of gastrodin or normal saline. After 2wk, the rats were sacrificed. FluoroGold was used to label survival RGCs. Immunostaining with anti-Iba1 in the retinal flat mounts to calculate the microglia density in the ganglion cell layer (GCL). Changes in microglial cytokines, tumour necrosis factor-alpha (TNF-α) and inducible NO synthase (iNOS) were examined with Western blot and reverse transcription-quantitative polymerase chain reaction. Expression levels of total and phosphorylated p38 mitogen activated protein kinase (MAPK) were determined by Western blot. RESULTS: Results showed that AOH induced significant loss of RGCs and severe microglia activation in the GCL. Besides, AOH increased the phosphorylation of p38 MAPK and promoted the release of microglial cytokines in the retinas. Intraperitoneal injection with dose-dependent gastrodin significantly reduced the loss of RGCs and inhibited retinal microglia activation, accompanied with the decreased expression levels of microglial cytokines and p38 MAPK phosphorylation. CONCLUSION: Gastrodin exerts a neuroprotective effect on RGCs in an acute glaucoma animal model via inhibiting microglia activation and microglial-mediated neuroinflammation. The finding demonstrates the potential application of gastrodin in the neuroprotective therapy of acute glaucoma and other retinal neurodegenerative diseases characterized by microglia activation and RGCs death.

Aqueous proinflammatory cytokines in acute primary angle-closure eyes.

AIM: To evaluate changes of proinflammatory cytokines in aqueous humor of patients with acute primary angle-closure (APAC) and age-related cataracts. METHODS: Twenty eyes of 20 APAC patients and 15 eyes of 15 age-related cataract patients were included in this cross-sectional study. Aqueous humor samples were collected prospectively. The levels of 20 proinflammatory cytokines were evaluated in the aqueous humor of the APAC and cataract patients using the multiplex bead immunoassay technique. Clinical data were collected for correlation analysis. RESULTS: Seven of the 20 proinflammatory cytokines included in the magnetic bead panel were detectable in both APAC eyes and cataract eyes: interleukin (IL)-10, IL-12, IL-15, IL-21, IL-6, chemokine (C-C motif) ligand 20, and tumor necrosis factor alpha (TNF-α). IL-27 was only detectable in APAC eyes. Compared with the cataract eyes, the APAC eyes had significantly elevated concentrations of IL-12 (P=0.036), IL-15 (P=0.001), IL-6 (P=0.012), and IL-27 (only detectable in APAC eyes). Age was positively correlated with IL-12 (P=0.022) and IL-6 (P=0.037), and time elapsed between APAC onset and aqueous humor samples collection was positively correlated with IL-15 (P=0.037), IL-27 (P=0.040), and TNF-α (P=0.042). CONCLUSION: Several proinflammatory cytokines including IL-12, IL-15, IL-6 and IL-27, were elevated in the APAC eyes and may be implicated in its pathologic mechanism.

[Study on antidepressant components of sucrose ester from Polygala tenuifolia].

OBJECTIVE: To investigate the antidepressant components of Polygala tenuifolia. METHOD: The chromatographic method was used to isolate and purify the chemical constituents, their structures were identified by spectral analysis, MTT method was applied to investigate their cytotoxic activities. RESULT: Nine compounds were isolated from the roots of P. tenuifolia. Their structures were identified as sibiricose A, (1), sibiricose A5 (2), tenuifoliside A (3) and 3', 6-disinapoyl sucrose (4), sibiricose A6 (5), 3, 4, 5-trimethoxycinnamate (6), polygalaxanthone III (7), tenuifolioses A (8), tenuifolioses H (9) and some compounds' activities to PC12 were observed. CONCLUSION: Compound 1 was isolated from this plant for the first time. Compounds 2,3 could protect PC12 cells damage induced by P. tenuifolia.

A spectroscopic study of the 3(1) pi g Rydberg state of 7Li2.

With pulsed optical-optical double resonance (OODR) fluorescence excitation spectroscopy Rydberg states of 7Li2 in the energy region of 35,500-38,000 cm-1 were studied and 146 transitions into the 3(1) pi g state of 7Li2 were measured. They were assigned to 10 vibrational levels of the 3(1) pi g state. A new set of Dunham constants, RKR potential curve, and Franck-Condon factors for the transitions form the A 1 sigma u+ state are derived. The perturbations between the 4(F)1 sigma g+, 5 (1) sigma g+, 6 (1) sigma g+, 2 (G) 1 pi g Rydberg states with the 3 (1) pi g state are discussed. The lambda-doubling splitting of the observed levels can be ignored with our accuracy (0.2 cm-1).