Golgi-targeted NIR fluorescent probe with large stokes shift for real-time monitoring of nitric oxide in depression model.

Depression is a debilitating mental illness that poses a serious threat to human health. Nitric Oxide (NO), as an important gasotransmitter, is closely associated with the pathogenesis of depressive disorders. Effective monitoring of NO fluctuation is beneficial for the diagnosis of depression and therapy assessment of antidepressants. Currently, there is a lack of effective methods for rapidly and sensitively identifying NO and elucidating its relationship with depression diseases. Herein, we developed a NIR dye TJ730-based fluorescent probe TJ730-Golgi-NO incorporating benzenesulfonamide as a Golgi-targeted moiety and the thiosemicarbazide group for NO detection. The probe exhibited turn-on fluorescence ability and a large Stokes shift of 158 nm, which shows high sensitivity, selectivity, and rapid response (<1 min) for NO detection. TJ730-Golgi-NO could detect exogenous and endogenous NO in cells stimulated by Glu and LPS, and target Golgi apparatus. Moreover, we disclose a significant increase of NO in the depression model and a weak fluorescence evidenced in the fluoxetine-treated depression mice. This study provides a competent tool for studying the function of NO and helping improve the effective treatment of depression diseases.

High-performance fluorescence probe for fast and specific visualization of norepinephrine in vivo and depression-like mice.

Norepinephrine (NE), as an important neurotransmitter, is closely associated with the pathogenesis of anxiety and depressive disorders. Effective monitoring of NE fluctuation aids in the diagnosis of depression and the therapeutic assessment of the antidepressant intervention. The construction of novel fluorescent probes with high specificity towards NE for imaging in depression models is still in demand urgently. In this work, a novel resorufin-based red-emitting fluorescent probe for real-time tracking NE was developed. NE can significantly increase the fluorescence of probe LNE by triggering deprotection of carbonothioate ligand via nucleophilic substitution. The probe LNE demonstrated significant NE selectivity and sensitivity over other analytes in vitro. In addition, probe LNE showed a fast response time (<10 min), and the change in fluorescence signal was positively linked with NE concentration, which could be utilized to track the dysregulation of NE in vivo. More importantly, this powerful probe was successfully employed for real-time visual and imaging of NE in living cells and depression-like behavior animals.

A fluorescence "turn-on" probe for Cu (â ¡) based on flavonoid intermediates generated by copper-induced oxidative cyclization and its fluorescence imaging in living cells.

A fluorescence "turn-on" probe for Cu (Ⅱ) ions was prepared based on the condensation reaction of coumaraldehyde and 1-hydroxy-2-acetylnaphthalene. A strong fluorescent flavonoid intermediate was formed and verified by the NMR and ESI-MS experiments. The water-soluble and pH dependence experiments were performed to confirm the optimal solvent condition (CH3CN: HEPES = 1:1, v/v, pH = 7.2-7.4). The dynamic experiments indicated that the formation process of the intermediate catalyzed by Cu(Ⅱ) ions was probably pseudo-first-order reaction process. The probe showed good selectivity toward copper ions and almost no interference except Ag+ ions by the selectivity and competitive experiments. The HeLa cells were used in the cell fluorescence imaging tests and it was demonstrated that the probe could be used in the phycological condition and showed weak cytotoxicity by the MTT experiments.

Papaverine Infusion Through Aortic Root before Cardiac Self-recovery in Heart Valve Replacement with TiO2 Nanocrystalline Film Material.

This work was to investigate TiO2 nanocrystalline film material in heart valve replacement (HVR) and the effect of papaverine infusion through the aortic root before cardiac self-recovery during the HVR. TiO2 nanocrystalline films were prepared by radio frequency (RF) reactive sputtering. The crystallization characteristics and surface morphology of TiO2 nanocrystalline films were observed by X-ray diffraction and scanning electron microscopy, and the anti-platelet adhesion and anti-coagulation properties of the films were analyzed. 86 patients with heart valve disease were selected and all underwent HVR. They were randomly divided into a control group (routine treatment) and an experimental group (papaverine perfusion through aortic root), with 43 cases in each group. The rate of cardiac self-recovery and the dosage of dopamine were observed. The results showed that the TiO2 nanocrystalline film was composed of a large number of uniform particles, and the average particle size was about 18.97 ± 7.28 nm. The rate of cardiac self-recovery in the experimental group was 97.67%, which was significantly higher than that in the control group (67.44%) (P< 0.05). The dosage of epinephrine, dopamine, and duration of cardiopulmonary bypass (CPB) assistance in the observation group were less than those in the control group (P < 0.05). These results indicated that TiO2 nanocrystalline film could be used in HVR, and papaverine infusion through aortic root before HVR and myocardial protection measures can significantly improve the rate of cardiac self-recovery and promote postoperative recovery.

A novel naphthalimide-based fluorescent probe for the colorimetric and ratiometric detection of SO2 derivatives in biological imaging.

SO2 is a well-known signal molecule and one of reactive sulfur species, which closely participates in many metabolic processes. While unbalanced metabolism of sulfur dioxide can lead to serious complications of various diseases. Therefore, a rapid and accurate monitoring of SO2 derivatives with high selectivity and sensitivity would be beneficial for their bio-analytic studies. Herein, a novel ratiometric fluorescent probe (NG-TCF) based on ICT mechanism for monitoring SO2 was developed. The probe underwent a nucleophilic addition of HSO3-/SO32- to give rise to a 120 nm blue-shift dual-emission signal changes in enhanced green channel and subdued red channel under a single wavelength excitation. The probe showed fast response rate (within 7 min), good sensitivity (the detection limit is 1.53 µM), and specific response toward HSO3-/SO32- over other bio-species, including H2S and ClO-. Moreover, the probe can be applied for visual ratio imaging of exogenous and endogenous SO2 derivatives in living cells.

A reactive probe for Co2+ ion detection based on a catalytic decomposition process and its fluorescence imaging in living cells.

A novel reactive fluorescent probe for cobalt ions was prepared based on integration of thiourea functional groups, coumarin, and naphthalimide fluorophores. There was no fluorescence observed for the probe itself, however, in the presence of cobalt ions, catalytic decomposition occurred for the probe and coumarin molecular fragments were produced that emitted blue fluorescence. This enabled the probe to be used as a 'turn on' reagent for detection of cobalt ions. Under physiological pH conditions and in appropriate solvent systems, an obvious fluorescence enhancement for cobalt ions was observed in selective experiments. Competition experiments indicated that cobalt ions could still induce fluorescence enhancement in the presence of other metal ions. Sensitivity experiments showed that the detection limit for cobalt ions was 6.0 nM. Dynamics research demonstrated that the catalytic process was a pseudo-first-order reaction and the reaction constant (kobs ) was calculated to be 1.49 × 10-2 min-1 . In addition, the mechanism of catalytic decomposition could be demonstrated using electrospray ionization mass spectrometry and thin layer chromatography experiments. Cell fluorescence imaging experiments demonstrated that the probe could be used to detect cobalt ions in living HeLa cells.

Giant Atrial Septal Artery Aneurysm with a Fistula to the Right Atrium.

An atrial septal artery aneurysm is a rare disease, especially accompanied with a fistula. During clinical practice, it is very important to clear the anatomical details of the coronary aneurysm before operation. In the current article, we report a giant atrial septal artery aneurysm originating from a branch of the RCA combined with a coronary right atrial fistula. The coronary artery aneurysm should be evaluated using multiple diagnostic and imaging modalities, such as echocardiography, coronary artery angiography, magnetic resonance imaging, and cardiac CT, especially three-dimensional reconstruction, which could help us to distinguish the physiological and anatomical characteristics of the CAA and fistula.

First Report of Stagonosporopsis vannaccii Causing Leaf Spot on Crassocephalum crepidioides in China.

Crassocephalum crepidioides (Benth.) S. Moore, native to tropical Africa, is an important invasive weed in many countries, seriously threatening the safety of agricultural ecosystem. During December 2018, 100% of C. crepidioides plants exhibited leaf spots in the Kudzu (Pueraria lobata) garden in Tianlin County, Baise City, Guangxi, China (24°40'20.42″N, 106°11'33.51″E), but Kudzu was not affected by this disease. The leaf spots appeared as small brown spots surrounded by a yellow-green halo initially, enlarged to subrotund or irregular in shape, slightly sunken, then developed as a dark brown to dark spot with grey-white necrotic center (Supplementary Fig. 1 a,b), and exuded an orange droplet under high humidity conditions (Supplementary Fig. 1 c). Symptomatic leaf tissues were cut into small pieces (5 x 5 mm) from the junction of necrotic and healthy tissues, and small pieces were disinfected in 75% ethanol solution for 30 s and 0.1% mercury dichloride for 30 sec, then rinsed with sterile water 3 times. These tissues were plated onto potato dextrose agar (PDA) medium and incubated in a thermostatic incubator at 28°C under natural sunlight conditions. Four isolates with similar morphological features were obtained after purification. Colonies of these isolates exhibited creme-orange margins and aerial mycelium was sparse. The colonies formed concentric circles on the surface that were fusco-black, violet-slate and vinaceus-grey (from centre to edge), fusco-black on the reverse after 7 days (Supplementary Fig. 2 a,b), and then the pycnidia and conidia produced for about 30 days (Supplementary Fig. 2 c). Pycnidia of representative isolate YTH-12 were black, subglobose, and unilocular, 95.60-168.27 µm (average 128.32 µm) (n = 40) in diameter. The ostiole was single and central, slightly papillate to papillate and occasionally rostrate (Supplementary Fig. 2 d). Conidia were hyaline, oval to elliptical, aseptate, 2.30 to 5.83 × 1.42 to 3.50 µm (average, 4.36 × 2.03 µm) (n = 50) (Supplementary Fig. 2 e). These morphological characters are consistent with those described for Stagonosporopsis vannaccii (Crous et al. 2019). To further identify the isolate YTH-12, the rDNA internal transcribed spacer (ITS) region, 28s large subunit ribosomal RNA (LSU), RNA polymerase II second largest subunit (RPB2) gene and ß-tubulin (TUB2) gene were amplified by polymerase chain reaction using the primer pairs ITS1/ITS4 (White et al. 1990), LR0R (Rehner and Samuels 1994)/LR7 (Vilgalys and Hester 1990), Btub2Fd/Btub4Rd (Woudenberg et al. 2009) and RPB2-5F2 (Sung et al. 2007)/fRPB2-7cR (Liu et al. 1999), respectively. The PCR products were purified and sequenced by Sangon Biotech Co. Ltd. (Shanghai, China). The sequences were deposited in GenBank (accession nos. MN892355, MN893911, MN905510 and MN905511). The ITS (522 bp), LSU (1313 bp), TUB2 (380 bp) and RPB2 (1193 bp) nucleotide sequences showed 100% identity to S. vannaccii strain LFNO148 (accession nos. MK519453, MK519452, MK519454 and MN534891). Phylogenetic analysis based on the multi-locus sequences of ITS, LSU, RPB2 and TUB2 was performed in MEGA version 6.0 (Chen et al. 2015). The relative stability of the branches was evaluated by bootstrapping with 1000 replications. The isolate YTH-12 was placed in the same clade as S. vannaccii with 100% bootstrap support. Based on morphology and molecular analyses, this pathogen was identified as S. vannaccii. To satisfy Koch's postulates, the isolate YTH-12 was inoculated on leaves of C. crepidioides plants. Twenty punctured leaves and twenty unwounded leaves were inoculated with a 5-mm-diameter mycelial disc, respectively. Leaves inoculated with sterile PDA discs were used as blank controls. Plants were maintained in a growth chamber (25°C-28°C and relative humidity 80%-90%). Brown spots were observed on inoculated leaves (both punctured and unwounded) about 30 hours after inoculation and typical symptoms appeared about 55 hours after inoculation (Supplementary Fig. 1 d), and the diseased leaves produced black pycnidia and orange droplet 10 days after inoculation (Supplementary Fig. 1 e). All inoculated leaves developed symptoms similar to those on the naturally infected plants in the garden and the disease incidence reached 100%, whereas the control leaves remained symptomless (Supplementary Fig. 1 f). The same fungus was re-isolated from inoculated leaves. To our knowledge, this is the first report of S. vannaccii causing leaf spot on C. crepidioides in China. So far, Stagonosporopsis vannaccii has been reported as a plant pathogenic fungus only in Brazil, causing anthracnose symptoms on pods of soybean (Crous et al. 2019). Crassocephalum crepidioides is a widely distributed weed. If S. vannaccii has strong host specificity, it is possible to be used as a biocontrol fungus to control the weed. Conversely, if the fungus has a wider host range, C. crepidioides may act as a good bridge to spread the pathogen. This study helps to deepen the understanding of S. vannaccii and its associated plant diseases.

Synthesis and application of a "turn on" fluorescent probe for glutathione based on a copper complex of coumarin hydrazide Schiff base derivative.

Discrimination and quantification of intracellular biothiols, such as cysteine (Cys), homocysteine (Hcy), glutathione (GSH) under physiological conditions is significant for academic research and disease diagnosis. A new fluorescent probe (complex 1-Cu2+) for discriminate detection of GSH was prepared by copper ions coordinate with coumarin carbohydrazide Schiff base derivative 1. In suitable buffer solution (CH3CN: HEPES = 3:2, v/v) and under appropriate pH condition (pH = 7.2-7.4), the UV-vis spectroscopy experiments showed that compound 1 and copper ion exhibited a 1:1 ratio binding mode and moderate binding ability. Fluorescence quenching of compound 1 was observed when it complexed with Cu2+ ions. An obviously fluorescence restoration appeared after addition of GSH to the solution of probe, which also exhibited a highly selectivity relative to cysteine (Cys) and homocysteine (Hcy) in the amino acid competitive experiments. The minimum detection limit was calculated to 0.12 µM by fluorescent method, which was distinctly below the physiological concentration of GSH in live cells. Its biological application to detect the endogenous GSH was further proved by the HepG2 cell fluorescence image test.

Synthesis and Application of an Aldazine-Based Fluorescence Chemosensor for the Sequential Detection of Cu²âº and Biological Thiols in Aqueous Solution and Living Cells.

A fluorescence chemosensor, 2-hydroxy-1-naphthaldehyde azine (HNA) was designed and synthesized for sequential detection of Cu(2+) and biothiols. It was found that HNA can specifically bind to Cu(2+) with 1:1 stoichiometry, accompanied with a dramatic fluorescence quenching and a remarkable bathochromic-shift of the absorbance peak in HEPES buffer. The generated HNA-Cu(2+) ensemble displayed a "turn-on" fluorescent response specific for biothiols (Hcy, Cys and GSH) based on the displacement approach, giving a remarkable recovery of fluorescence and UV-Vis spectra. The detection limits of HNA-Cu(2+) to Hcy, Cys and GSH were estimated to be 1.5 µM, 1.0 µM and 0.8 µM, respectively, suggesting that HNA-Cu(2+) is sensitive enough for the determination of thiols in biological systems. The biocompatibility of HNA towards A549 human lung carcinoma cell, was evaluated by an MTT assay. The capability of HNA-Cu(2+) to detect biothiols in live A549 cells was then demonstrated by a microscopy fluorescence imaging assay.

A novel lysosomal targeted near-infrared probe for ratio detection of carbon monoxide in cells and in vivo.

Carbon monoxide (CO) as an endogenous gas signaling molecule possesses important physiological functions and is of great significance in the treatment of various diseases. Real-time tracking of CO in living organisms has become a research hotspot in recent years. This article presents a lysosomal targeted near-infrared ratio fluorescence probe (TBM-CO) for selective detection of CO based on the dicyanoisophorone skeleton and morpholine fragment. The probe TBM-CO with weak ICT effect can be transformed to precursor TBM-NH2 with strong ICT effect by the traditional Tsuji-Trost reaction procession in the presence of Pd2+ ions. The mechanism was proved by DFT calculation or the MS and HPLC results respectively. In the near-infrared region an obvious ratio fluorescence intensity change (F686 / F616) is observed in vitro spectral experiments. The concentration titration experiments indicate that there is a good liner relationship between the ratio fluorescence intensity and the concentration in the range of 0 to 50 µM (R2 = 0.996) and the detection limit is calculated as 0.38 µM. The cell fluorescence imaging and co-localization experiments further demonstrate that TBM-CO is able to detect the exogenous and endogenous CO in lysosomal subcellular organelle. Finally, it was used to detect the changes of CO concentration in living mice successfully. In short, a probe with three advantages of near-infrared emission, ratiometric fluorescence and organelle targeting was reported and used to detect CO successfully in cells and in living mice.

TPE-based fluorescent probe for dual channel imaging of pH/viscosity and selective visualization of cancer cells and tissues.

The development of efficient fluorescence-based detection tools with high contrast and accuracy in cancer diagnosis has recently attracted extensive attention. Changes in the microenvironments between cancer and normal cells provide new biomarkers for precise and comprehensive cancer diagnosis. Herein, a dual-organelle-targeted probe with multiple-parameter response is developed to realize cancer detection. We designed a tetraphenylethylene (TPE)-based fluorescent probe TPE-PH-KD connected with quinolinium group for simultaneous detection of viscosity and pH. Due to the restriction on the double bond's rotation, the probe respond to viscosity changes in the green channel with extreme sensitivity. Interestingly, the probe exhibited strong emission of red channel in acidic environment, and the rearrangement of ortho-OH group occurred in the basic form with weak fluorescence when pH increased. Additionally, cell colocalization studies revealed that the probe was located in the mitochondria and lysosome of cancer cells. Following treatment with carbonyl cyanide m-chloro phenylhydrazone (CCCP), chloroquine, and nystatin, the pH or viscosity changes in the dual channels are also monitored in real-time. Furthermore, the probe TPE-PH-KD could effectively discriminate cancer from normal cells and organs with high-contrast fluorescence imaging, which sparked more research on an efficient tool for highly selectively visualizing tumors at the organ level.

Occurrence and characterization of selected organochlorine contaminants in outdoor dust collected from Xinxiang, a fast developing city in North China.

As facile "environmental media", the outdoor dust may reflect the changes of contaminants in environment more promptly. In the present study, selected organochlorine contaminants (OCs) include hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCB) were detected in 20 outdoor dust samples collected from Xinxiang City. The concentrations of ΣHCHs, ΣDDTs, HCB, and PeCB in dust were in the range of 0.18-5.05 ng/g dry weight, 0.44-13.50 ng/g dry weight, 0.13-51.61 ng/g dry weight and ND-0.74 ng/g dry weight, respectively. Long-range transport, historical use, and recent impact of impure pesticides might be the main sources of OCs in the outdoor dust. The results of this study indicated that impure pesticide application maybe an important source of DDTs and HCB in the environment.

Sequential detection of hypochlorous acid and sulfur dioxide derivatives by a red-emitting fluorescent probe and bioimaging applications in vitro and in vivo.

Hypochlorous acid (HOCl) and sulfur dioxide derivatives (SO3 2-/HSO3 -) play critical roles in complex signal transduction and oxidation pathways. Therefore, it is meaningful and valuable to detect both HOCl and SO2 derivatives in biosystems by a fluorescence imaging assay. In this work, we developed a red-emitting fluorescent probe (DP) by the condensation of malononitrile and phenothiazine derivatives through a C[double bond, length as m-dash]C double bond. DP was designed with a donor-π-acceptor (D-π-A) structure, which enables absorption and emission in the long wavelength region. In the presence of HOCl, specific oxidation of the thioether of phenothiazine in DP to a sulfoxide derivative (DP[double bond, length as m-dash]O) occurs, resulting in a hypochromic shift (572 nm to 482 nm) of the absorption spectra and "OFF-ON" response of the maximum emission at 608 nm. After the activation of the C[double bond, length as m-dash]C double bond by oxidation, DP[double bond, length as m-dash]O reacts specifically with SO3 2-/HSO3 - via a 1,4-nucleophilic addition reaction leading to a decrease in the intensity of the absorption and emission spectra, which enabled the realization of sequential detection of HOCl and SO3 2-/HSO3 - by a single fluorescent probe. The detection limits of DP for HOCl and SO3 2-/HSO3 - were calculated to be 81.3 nM and 70.8 nM/65.1 nm, respectively. The results of fluorescence microscopic imaging indicated that DP shows potential for the detection of intracellular HOCl and SO3 2-/HSO3 -. Using adult zebrafish and nude mice as live animal models, DP was successfully used for the fluorescence imaging of HOCl and SO3 2-/HSO3 - in vivo.

A novel flavone-based ESIPT ratiometric fluorescent probe for selective sensing and imaging of hydrogen polysulfides.

Hydrogen polysulfides (H2Sn) as an important member of reactive sulfur species is closely relevant to many physiological functions in redox homeostasis and metabolism. Dual-channel monitor the changes of H2Sn level in vivo is highly desired. Herein we design a simple ratiometric fluorescent probe based on flavone skeleton for highly selective detection of H2Sn. The probe HF-NA-MC bearing 2-fluoro-5-nitrobenzoic acid group inhibited the intramolecular ESIPT process, which show the blue fluorescence of adjacent naphthalene unit. In the presence of H2Sn, the enol form of probe is converted to conjugated keto form, resulted in a 90 nm red-shift of fluorescence emission from 450 nm to 540 nm. The ratiometric intensity (I540/I450) of the probe exhibits a good linear relationship toward H2Sn in the range of 0-120 µM, and the detection limit is estimated to be 0.63 µM. The ratiometric fluorescent probe shows high specificity and anti-interference ability for H2Sn over other related reactive sulfur species. The probe HF-NA-MC shows promising outlook and could be applied to the confocal imaging of H2Sn by dual emission channels in Hela cells.

A red-emission fluorescence probe based on 1,4-addition reaction mechanism for the detection of biothiols in vitro and in vivo.

In this work, a new fluorescence probe (DC) with a donor-π-acceptor (D-π-A) structure was designed and synthesized for the detection of three kinds of biothiols (Cys, Hcy and GSH) in live cells and organisms. DC displayed an intense red-emission centered at 625 nm. In the presence of biothiols, the nucleophilic addition reaction between the C=C double bond of DC and the sulfhydryl group (-SH) of biothiols occurred, resulting in obvious fluorescence quenching responses. DC exhibited high selectivity towards biothiols over other common bioactive species with low detection limits (0.26, 0.43, and 0.44 µM for Cys, Hcy and GSH, respectively). In addition, DC displayed a rapid response to biothiols within 4 min. The applications of DC in biothiols detection and imaging were then successfully demonstrated for the real-time monitoring of endogenous and exogenous biothiols in live cells and live animals.

Dapagliflozin Protects Methamphetamine-Induced Cardiomyopathy by Alleviating Mitochondrial Damage and Reducing Cardiac Function Decline in a Mouse Model.

Background: Methamphetamine (METH)-induced cardiovascular toxicity has been attributed to its destructive effect on mitochondrial function at least to some extent. Previous studies highlighted the benefits of dapagliflozin (DAPA) on the cardiovascular system, but the response of METH-induced cardiomyopathy to DAPA is never addressed before. The present study aimed to investigate the potential ability of DAPA in preventing METH-induced cardiomyopathy. Materials and Methods: C57BL/6 mice were randomly divided into control group (n = 24), METH group (n = 24), and METH + DAPA group (n = 24). The METH-induced cardiomyopathy group received intraperitoneal METH injections at gradually increasing doses thrice weekly for 14 weeks. Mice in the METH + DAPA group were simultaneously treated with DAPA 1 mg/kg/day by intragastric administration. Echocardiography was performed to assess cardiac function. Reactive oxygen species (ROS), JC-1, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays were performed to evaluate oxidative stress, mitochondrial damage, and apoptosis, respectively. Mitochondrial and apoptosis-related protein expression was measured by western blotting. Results: Mice exposed to METH exhibited reduced cardiac function (left ventricular ejection fraction [LVEF]: 56.51 ± 6.49 vs. 73.62 ± 1.42, p < 0.01), fibrotic remodeling, and mitochondrial dysfunction, leading to apoptosis (apoptotic cells%: 7.4 ± 1.3 vs. 1.3 ± 0.5, p < 0.01). DAPA significantly reduced mitochondrial dynamics and function, ROS, apoptosis (apoptotic cells%: 2.4 ± 0.8 vs. 7.4 ± 1.3, p < 0.01), cardiac function decline (LVEF: 70.99 ± 4.936 vs. 56.51 ± 6.49, p < 0.01), and fibrotic remodeling. These results indicated that DAPA could be considered as an effective therapeutic agent in the protection against METH-associated cardiomyopathy. Conclusion: DAPA protects against METH-induced cardiomyopathy in mice by decreasing mitochondrial damage and apoptosis.

Acetylation and Phosphorylation of Proteins Affect Energy Metabolism and Pork Quality.

Preslaughter handling has been shown to significantly affect meat quality, but the mechanisms are not fully understood. In this study, we investigated protein phosphorylation and acetylation in pig muscles at early postmortem time and their associations with meat quality attributes. Thirty pigs were randomly assigned to traditional (TH, n = 15) or mild handling (MH, n = 15). Compared with TH, MH reduced the incidence of pale, soft, and exudative (PSE) or dark, firm, and dry (DFD) pork. MH induced 65 and 20 peptides that match with 39 and 12 proteins to be more highly phosphorylated and acetylated, respectively. Creatine kinase, ß-enolase, α-1,4-glucan phosphorylase, tropomyosin, and myosin heavy chain isoforms 1, 4, and 7 were found to be simultaneously phosphorylated and acetylated, which may involve glycolysis, tight junctions, and muscle contraction. The phosphorylation and acetylation levels of differential proteins showed significant correlations with meat quality traits. These findings indicate that preslaughter MH can improve meat quality by regulating protein phosphorylation and acetylation involving energy metabolism in muscle.

A diaminomaleonitrile-appended BODIPY chemosensor for the selective detection of Cu2+ via oxidative cyclization and imaging in SiHa cells and zebrafish.

A specific Cu2+ sensor, 2-amino-3-(BODIPYmethyleneamino)maleonitrile (BDM), was established by a simple dehydration between BODIPY and diaminomaleonitrile. Cu2+ could be recognized by BDM over other competing metal ions in acetonitrile with distinct fluorescence emission signal response. Upon the addition of Cu2+ to BDM in acetonitrile, the maximum absorption at approximately 530 nm on the longer wavelength side was quenched, and the emission at 530 nm was ignited simultaneously. The fluorescence intensity enhancement could reach a maximum of 204 times the intensity of the BDM blank solution. The fluorescence "off-on" effect is established according to the Cu2+-induced fast intramolecular oxidative cyclization reaction, which could be deduced from the formation of an imidazole ring appended to the cyclization product (2-BODIPY-1H-imidazole-4,5-dicarbonitrile, BMC). Single-crystal structure analysis of the sensor BDM and cyclization product BMC further demonstrated this oxidative cyclization. Finally, the Cu2+ recognition property of BDM was validated in SiHa cells and living zebrafish. Additionally, the blood-brain barrier of the zebrafish can be penetrated by the BDM dye and the neuron cells in the brain were stained.

Highly sensitive fluorescence probe based on functional SBA-15 for selective detection of Hg2+ in aqueous media.

An inorganic-organic hybrid fluorescence chemosensor (R6G-SBA-15) was prepared by covalent immobilization of a Rhodamine 6G derivative within the channels of mesoporous silica material SBA-15 via triethoxysilane groups. The primary hexagonally ordered mesoporous structure of SBA-15 is preserved after the grafting procedure. R6G-SBA-15 features effectively chromogenical and fluorogenical responses with a broad pH span (2-10), excellent sensitivity to environmentally relevant mercury levels lower to ppb range. It also exhibits Hg(2+)-specificity over various competitive cations, including alkali and alkaliearth, the first-row transition metals as well as heavy metals such as Pb(2+), Cd(2+) and Ag(+), etc. Additional experiments establish the well-fitted linearity function of the fluorescent intensity with the concentration of Hg(2+) in aqueous solution, suggesting the possibility for real-time qualitative or quantitative detection of Hg(2+) and the convenience for potential application in toxicology and environmental science.