GSH Solution Research Articles

MnO2-based dual channel surface plasmon resonance fiber sensor for trace glutathione and refractive index detection.

Glutathione (GSH) plays vital role in human biological systems, so its rapid and sensitive detection is necessary for health condition monitoring. In this work, a simple structure for dual channel GSH and refractive index (RI) detection is proposed. By introducing Au-MnO2 thin film coating on the fiber surface for the first time, GSH solution would lead to the dissolution of MnO2, the change in GSH levels could be monitored over a short period in channel 2. For channel 1, ITO-Ag thin film is applied for RI change detection. After optimization, the GSH detection sensitivity reached about -2.361 nm/mM in the range of 0.005-50 mM, and the RI sensitivity reached 1704.252 nm/RIU in the range of 1.331-1.3895 RIU. Channel 1 could also put into GSH detection in the high concentration scale to enlarge the sensor's range and 0.095 nm/mM of sensitivity is acquired within the range of 50-600 mM. With the presence of MnO2 film, the detection sensitivity increased 25.663 times. Neither channel interferes with the operation of the other. Proposed sensor provides stability, high selectivity and elevation in GSH detection sensitivity, which shows great potential for environmental and biological detection field and their applications.

Insight into the Structural and Dynamical Processes of Peptides by Means of Vibrational and Ultrasonic Relaxation Spectroscopies, Molecular Docking, and Density Functional Theory Calculations

We report a detailed investigation of the vibrational modes, structure, and dynamics of glutathione (GSH) solutions using ultrasonic relaxation spectroscopy, FT-IR vibrational spectroscopy, and electronic absorption measurements. The experimental data were analyzed using density functional theory (DFT) and molecular docking calculations. Three distinct Debye-type relaxation processes can be observed in the acoustic spectra, which are assigned to conformational changes between GSH conformers, the self-association of GSH, and protonation processes. The standard volume changes for each process were estimated both experimentally and theoretically, revealing a close resemblance among them. The higher the effect of the relaxation process in the structure, the greater the induced volume changes. From the temperature dependence of specific acoustic parameters, the thermodynamic characteristics of each process were determined. The experimental FT-IR spectra were compared with the corresponding theoretically predicted vibrational spectra, revealing that the GSH dimers and extended conformers dominate the structure of GSH solutions in the high-concentration region. The absorption spectra in the ultraviolet region confirmed the gradual aggregation mechanism that takes place in the aqueous GSH solutions. The results of the present study were discussed and analyzed in the framework of the current phenomenological status of the field.

Disulfide bond cross-linked three-dimensional graphitic carbon nitride nanocomposites with glutathione responsive fluorescence for cancer-cell specific bioimaging

The polymeric graphitic carbon nitride (g-C3N4) nanomaterials with non-toxicity, high stability, and photoluminescence property have promising application in bioimaging and biosensing. In this work, smart three-dimensional (3D) disulfide bond cross-linked g-C3N4 (CL-g-C3N4) nanocomposites with glutathione (GSH)-responsive fluorescence property were designed and developed for cancer cell-specific imaging. The g-C3N4 layered nanosheets with an average lateral size of 80–120 nm and mean thickness of ca. 0.5–1.0 nm were fabricated and used as building blocks. By combining several g-C3N4 nanosheets with non-fluorescent redox-sensitive disulfide bond-contained cross-linker, CL-g-C3N4 nanocomposites with a hydrodynamic particle size of ca. 270.5 nm were synthesized. The fluorescence of the CL-g-C3N4 nanocomposites was initially quenched due to the assembly of 2D g-C3N4 nanosheets into 3D structured nanocomposite caused by the crosslinking process. However, upon stirring them in a GSH solution with a concentration of 2 mM, which simulates the content in the cytoplasm of cells, the fluorescence was recovered to 89.3 % of its original intensity. This recovery was achieved through a thiol-disulfide exchange reaction, highlighting the GSH-responsive fluorescence recovery property of the nanocomposites. The cellular uptake traced images of CL-g-C3N4 in human cervix carcinoma (HeLa) cancer cells exhibited almost 3.5 times higher fluorescence intensity than that in human embryonic kidney (HEK 293 T) healthy cells owing to higher GSH concentration in cancer cells than that in healthy cells. The constructed CL-g-C3N4 nanocomposites should hold great promise as a fluorescence detector of cancer cells for early cancer diagnose.

Luminescent Water-Dispersible Nanoparticles Engineered from Copper(I) Halide Cluster Core and P,N-Ligand with an Optimal Balance between Stability and ROS Generation

The present work introduces the solvent exchange procedure as a route for conversion of the Cu4I4L2 complex, where the Cu4I4 cluster core is coordinated with two P,N-ligands (L), into an aqueous colloid. The analysis of both colloidal and supernatant phases revealed some losses in CuI going from the initial Cu4I4L2 complex to Cu2I2L3-based nanoparticles. The comparative analysis of IR, 31P NMR spectroscopy, ESI mass-spectrometry and luminescence data argued for a contribution of the “butterfly”-like structures of the Cu2I2 cluster core to Cu2I2L3-based nanoparticles, although the amorphous nature of the latter restricted structure evaluation from the PXRD data. The green luminescence of the colloids revealed their chemical stability under pH variations in the solutions of some amino acids and peptides, and to specify the temperature and concentration conditions triggering the oxidative degradation of the nanoparticles. The spin trap-facilitated ESR study indicated that the oxidative transformations were followed by the generation of reactive oxygen species (ROS). The physiological temperature level (310 K) enhanced the ROS generation by nanoparticles, but the ROS level was suppressed in the solution of GSH at pH = 7.0. The cytotoxicity of nanoparticles was evaluated in the M-HeLa cell line and is discussed in correlation with their cell internalization and intracellular oxidative transformations.

Synthesis of Hollow Calcium Carbonate Microspheres by a Template Method for DOX Loading and Release with Carbon Dots Photosensitivity.

Calcium carbonate, as the main inorganic component of human bones and teeth, has good biocompatibility and bioactivity and finds increasing applications in the field of bone drug carriers. In this study, hollow calcium carbonate microspheres were synthesized by a water hydrothermal method using folic acid as a template. Before drug loading, the prepared calcium carbonate microspheres were subjected to aminidation, carboxylation, and vinylenimine modification. The hollow calcium carbonate microspheres loaded with doxorubicin hydrochloride (DOX) were further incorporated with light-emitting carbon quantum dots(CQDs) and hyaluronic acid (HA). The result showed that the drug loading capacity in the as-prepared calcium carbonate was 179.064 mg/g. In the simulated solutions of cellular metabolism containing various concentrations of reduced glutathione(GSH), the sustained release of DOX was confirmed qualitatively by the luminescence of the CQDs. The DOX release rate was measured quantitively by UV absorption spectra. The highest release rate reached 85.99% in a simulated solution of 0.005 mol/L GSH solution, and the release rate could vary intelligently with the concentration.

Full factorial design, physicochemical characterization, ex vivo investigation, and biological assessment of glutathione-loaded solid lipid nanoparticles for topical application

l-Glutathione (GSH) has exceptional antioxidant activities against UVA irradiation-induced oxidative stress and is used widely for combatting skin ageing. However, topical administration of GSH is challenging due to its inability to penetrate the stratum corneum (SC). This study aims to evaluate the solid lipid nanoparticles (SLNs) carrier system for improving the skin penetration and stability of GSH. The GSH-loaded SLNs (GSH-SLNs) were prepared by the double emulsion technique and were optimized by a full factorial design. The optimized GSH-SLNs formulation had a mean particle size of 305 ± 0.6 nm and a zeta potential of + 20.1 ± 9.5 mV, suitable for topical delivery. The ex-vivo penetration study using human skin demonstrated a 3.7-fold improvement of GSH penetration across SC with GSH-SLNs when compared with aqueous GSH. GSH-SLNs prolonged antioxidant activity on UVA irradiated fibroblast cells when compared to GSH solution, preventing UVA-induced cell death and promoting cell growth for times over 48 h. This research has illustrated that as a carrier system, SLNs were able to enhance the physicochemical stability, skin penetration, and drug deposition in the viable epidermis and dermis layers of the skin for GSH, while also maintaining the ability to protect human skin fibroblast cells against oxidative stress caused by UVA irradiation. This delivery system shows future promise as a topical delivery platform for the topical delivery of GSH and other chemically similar bioactive compounds for improving skin health.

Development of Highly Sensitive and Stable Nitroxyl Probe for Visualization of Free Radical Reaction Induced by X-Ray Irradiation

<h3>Purpose/Objective(s)</h3> Visualization of radiation dose and tracks enable even safer and more accurate radiation therapy. It is already known that free radicals are generated by irradiation and imaging these free radicals will lead to an accurate understanding of the treatment dose and area after radiation therapy. We have been developing the free radical imaging methods using Dynamic Nuclear Polarization (DNP)-MRI with nitroxyl radicals as a redox probe (e.g., 1-Oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (Tempol)). We previously demonstrated that the mixed solution of Tempol and glutathione (GSH) was useful as a probe for detecting free-radical reactions, allowing us to observe the redox reaction after irradiation clearly. However, one of the problems was that the stability of the solution was limited. In order to apply this technology in vivo, we considered it was necessary to improve its stability. In this study, we focused on 4-Methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempo methacrylate; TempoMC) as a new redox probe that is stable in GSH solution, and further improved the imaging method. <h3>Materials/Methods</h3> To confirm the stability of TempoMC in various concentrations of GSH solutions, EPR signals were measured immediately after mixing and after 1 day, 3 days, and 7 days. The reduction of TempoMC by ascorbic acid (AsA) was monitored by X-band EPR spectroscopy to demonstrate the redox imaging capability. To confirm the possibility of redox reaction between TempoMC/GSH solution with free radicals induced by X-ray. The glass capillaries including TempoMC and GSH were irradiated 10 Gy by Linac, and the ESR signals were measured. Free radical imaging by low filed type of dynamic nuclear polarization (DNP)-MRI was performed using phantom filled with TempoMC and GSH solution. <h3>Results</h3> In contrast to Tempol, which showed a sharp EPR signal decrease depending on the concentration of GSH, the signal of TempoMC was generally constant. In addition, TempoMC showed only a slight decrease in signal even after 7 days, proving that it exists in a stable state. After mixing the AsA solution, the ESR signal was gradually decreased by the redox reaction. The EPR signals of TempoMC capillaries were decreased by irradiation. The phantom including TempoMC radical were clearly visualized by DNP-MRI. As described above, TempoMC/GSH solution behaved similar reactivity to Tempol/GSH solution, proving to be more stable and more useful as a redox probe. <h3>Conclusion</h3> We evaluated TempoMC/GSH solution as a new useful redox probe. TempoMC /GSH solution is much more stable than the conventional Tempol/GSH solution, and is expected to be applied in the future, including in vivo.

An Off-Off fluorescence sensor based on ZnS quantum dots for detection of glutathione

Quantum dots (QDs) are excellent fluorescent indicators for chemical and biological analysis. In this paper, an Off-Off fluorescence sensor based on ZnS quantum dots was designed. It was found that Co2+ can quench the fluorescence of ZnS QDs, moreover glutathione (GSH) can further quench the fluorescence. Therefore, this method can be used for indirect detection of GSH. However, if change Co2+ into other metal ions, the system cannot be used to detect GSH indirectly. For direct detection GSH, that is adding GSH without Co2+, the fluorescence intensity changes little, while only amino acid or monosaccharide has no effect. When indirect detection of GSH based on this Off-Off fluorescent probe, the fluorescence quenching was linearly related to the concentration range of 1–300 μM GSH, and the detection limit could reach 0.48 μM, which can rival most Off-On and On-Off fluorescent probe. The relative standard deviation for parallel measurement of 300 μmol·L-1 GSH solution (for n = 10) was 1.43 %.

General Applicability of High-Resolution Continuum-Source Graphite Furnace Molecular Absorption Spectrometry to the Quantification of Oligopeptides Using the Example of Glutathione

This communication introduces the first-time application of high-resolution continuum-source molecular absorption spectrometry (HR CS MAS) for the quantification of a peptide. The graphite furnace technique was employed and the tripeptide glutathione (GSH) served as a model compound. Based on measuring sulfur in terms of carbon monosulfide (CS), a method was elaborated to analyze aqueous solutions of GSH. The most prominent wavelength of the CS molecule occurred at 258.0560 nm and was adduced for monitoring. The methodological development covered the optimization of the pyrolysis and vaporization temperatures. These were found optimally to be 250 °C and 2250 °C, respectively. Moreover, the effect of modifiers (zirconium, calcium, magnesium, palladium) on the absorption signals was investigated. The best results were obtained after permanent coating of the graphite tube with zirconium (total amount of 400 μg) and adding a combination of palladium (10 µL, 10 g L−1) and calcium (2 µL, 1 g L−1) as a chemical modifier to the probes (10 µL). Aqueous standard samples of GSH were used for the calibration. It showed a linear range of 2.5–100 µg mL−1 sulfur contained in GSH with a correlation coefficient R2 &gt; 0.997. The developed method exhibited a limit of detection (LOD) and quantification (LOQ) of 2.1 µg mL−1 and 4.3 µg mL−1 sulfur, respectively. The characteristic mass accounted for 5.9 ng sulfur. The method confirmed the general suitability of MAS for the analysis of an oligopeptide. Thus, this study serves as groundwork for further development in order to extend the application of classical atomic absorption spectrometry (AAS).

Application of thiol compounds to reduce acrylamide levels and increase antioxidant activity of French fries

The aim of this study was to examine the effects of thiol compounds, glutathione (GSH), cysteine (CYS) and N-acetylcysteine (NAC), on the color, antioxidant activity, total phenolic, ascorbic acid and acrylamide content of French fries which were fried at 180 °C for 6 min. Three different concentrations (0.5%, 1.0%, 2.0%) of each thiol compound were tested. Sulphite solution was used as a benchmark. According to the results, CYS and NAC solutions increased the antioxidant activity but GSH solution did not affect. The amount of ascorbic acid was highest in CYS (1.0%, 2.0%) and GSH (2.0%) treated samples. Although all pre-treatments decreased the acrylamide content, GSH2.0%, NAC2.0%, CYS (0.5%, 1.0%, 2.0%) provided 62–70% reduction. In addition, acrylamide showed a high correlation with L* (r=-0.82), a* (r=0.84), b* (r=0.77), ΔE (r=0.66), ascorbic acid (r=-0.79) and weak correlation with thiol content (r=-0.45). On the other hand, antioxidant activities had lack of correlation with acrylamide.

Influence of exogenous ascorbic acid and glutathione priming on mitochondrial structural and functional systems to alleviate aging damage in oat seeds

BackgroundLoss of vigor caused by seed aging adversely affects agricultural production under natural conditions. However, priming is an economical and effective method for improving the vigor of aged seeds. The objective of this study was to test the effectiveness of exogenous ascorbic acid (ASC) and glutathione (GSH) priming in the repairing of aged oat (Avena sativa) seeds, and to test the hypothesis that structural and functional systems in mitochondria were involved in this process.ResultsOat seeds were artificially aged for 20 days at 45 °C, and were primed with solutions (1 mmol L− 1) of ASC, GSH, or ASC + GSH at 20 °C for 0.5 h before or after their aging. Seed germination, antioxidant enzymes in the ASC-GSH cycle, cytochrome c oxidase (COX) and mitochondrial malate dehydrogenase (MDH) activities, and the mitochondrial ultrastructures of the embryonic root cells were markedly improved in aged oat seeds through post-priming with ASC, GSH, or ASC + GSH, while their malondialdehyde and H2O2 contents decreased significantly (P < 0.05).ConclusionOur results suggested that priming with ASC, GSH, or ASC + GSH after aging could effectively alleviate aging damage in oat seeds, and that the role of ASC was more effective than GSH, but positive effects of post-priming with ASC and GSH were not superior to post-priming with ASC in repairing aging damage of aged oat seeds. However, pre-priming with ASC, GSH, or ASC + GSH was not effective in oat seeds, suggesting that pre-priming with ASC, GSH, or ASC + GSH could not inhibit the occurrence of aging damage in oat seeds.

Thermogravimetric Analysis and Mass Spectrometry Allow for Determination of Chemisorbed Reaction Products on Metal Organic Frameworks.

Thermogravimetric analysis (TGA) is a technique which can probe chemisorption of substrates onto metal organic frameworks. A TGA method was developed to examine the catalytic oxidation of S-nitrosoglutathione (GSNO) by the MOF H3[(Cu4Cl)3(BTTri)8] (abbr. Cu-BTTri; H3BTTri = 1,3,5-tris(1H-1,2,3-triazol-5-yl)benzene), yielding glutathione disulfide (GSSG) and nitric oxide (NO). Thermal analysis of reduced glutathione (GSH), GSSG, GSNO, and Cu-BTTri revealed thermal resolution of all four analytes through different thermal onset temperatures and weight percent changes. Two reaction systems were probed: an aerobic column flow reaction and an anaerobic solution batch reaction with gas agitation. In both systems, Cu-BTTri was reacted with a 1 mM GSH, GSSG, or GSNO solution, copiously rinsed with distilled-deionized water (dd-H2O), dried (25 °C, < 1 Torr), and assessed by TGA. Additionally, stock, effluent or supernatant, and rinse solutions for each glutathione derivative within each reaction system were assessed by mass spectrometry (MS) to inform on chemical transformations promoted by Cu-BTTri as well as relative analyte concentrations. Both reaction systems exhibited chemisorption of glutathione derivatives to the MOF by TGA. Mass spectrometry analyses revealed that in both systems, GSH was oxidized to GSSG, which chemisorbed to the MOF whereas GSSG remained unchanged during chemisorption. For GSNO, chemisorption to the MOF without reaction was observed in the aerobic column setup, whereas conversion to GSSG and subsequent chemisorption was observed in the anaerobic batch setup. These findings suggest that within this reaction system, GSSG is the primary adsorbent of concern with regards to strong binding to Cu-BTTri. Development of similar thermal methods could allow for the probing of MOF reactivity for a wide range of systems, informing on important considerations such as reduced catalytic efficiency from poisoning, recyclability, and loading capacities of contaminants or toxins with MOFs.

Odorless Glutathione Microneedle Patches for Skin Whitening.

Glutathione is a natural anti-aging substance that prevents the oxidation of protein thiols from reactive oxygen species. In the pharmaceutical industry, reduced glutathione (GSH) has been widely used for skin whitening due to its ability to inhibit tyrosinase. However, its poor permeability and foul odor limit its use in skin applications. Herein, we report a GSH-loaded dissolving microneedle (MN) patch prepared with hyaluronic acid (HA) that enables enhanced permeation across the skin and reduces the foul odor of GSH. HA was selected to prepare odorless GSH solutions and used for MN fabrications as a carrier of GSH. GSH-loaded MN (GSH-MN) arrays prepared from MN-forming solution containing up to 10% GSH showed good pattern uniformity and appropriate mechanical properties for insertion into the skin. The GSH-MNs with a loading capacity of 17.4% dissolve within 10 min following insertion into porcine skin and release the loaded GSH without being oxidized. This new approach combines functional biopolymers to reduce the characteristic GSH odor and advanced transdermal delivery based on MN technology to enhance skin permeation without pain. We believe this technique could expand the application of GSH in many cosmeceutical fields.

Glutathione-responsive disassembly of disulfide dicyanine for tumor imaging with reduction in background signal intensity.

Near-infrared (NIR) fluorescence imaging has been proved as an effective modality in identifying the tumor border and distinguishing the tumor cells from healthy tissue during the oncological surgery. Developing NIR fluorescent probes with high tumor to background (T/B) signal is essential for the complete debulking of the tumor, which will prolong the survival rate of tumor patients. However, the nonspecific binding and “always-on” properties of the conventional fluorescent probes leads to high background signals and poor specificity.Method: To address this problem, glutathione (GSH)-responsive, two disulfide-bonded dicyanine dyes (ss-diCy5 and ss-diNH800CW) were synthesized. As synthesized dyes are quenched under normal physiological conditions, however, once reached to the tumor site, these dyes are capable of emitting strong fluorescence signals primarily because of the cleavage of the disulfide bond in the tumor microenvironment with high GSH concentration. Besides, the GSH-responsive behavior of these dyes was monitored using the UV-vis and fluorescence spectroscopy. The diagnostic accuracy of the aforementioned dyes was also tested both in tumor cells and 4T1-bearing mice.Results: The fluorescence signal intensity of disulfide dicyanine dyes was quenched up to 89% compared to the mono cyanine dyes, thus providing a very low fluorescence background. However, when the disulfide dicyanine dye reaches the tumor site, the dicyanine is cleaved by GSH into two mono-dyes with high fluorescence strength, thus producing strong fluorescent signals upon excitation. The fluorescent signal of the dicyanine was enhanced by up to 27-fold after interacting with the GSH solution. In vivo xenografts tumor studies further revealed that the fluorescence signals of aforementioned dyes can be quickly recovered in the solid tumor.Conclusion: In summary, the disulfide dicyanines dyes can provide a promising platform for specific tumor-activatable fluorescence imaging with improved T/B value.

Triggered doxorubicin release using redox-sensitive hyaluronic acid-g-stearic acid micelles for targeted cancer therapy

To develop a carrier for targeted drug delivery and triggered drug release in a reducing-tumor environment, reduction-sensitive hyaluronic acid-g-stearic acid (HCS) micelles were synthesized using a coupling agent. The HCS 40% was shown to have a more compact particle size than HCS 20% and the particle size of doxorubicin (DOX)-loaded HCS (HCSD) was increased relative to that of HCS micelles. The behavior of DOX release from HCSD showed that DOX was rapidly released in GSH (10 mM) solution. The site-specific targeting effect of HCSD nanoparticles was investigated by cellular uptake and competition assay at HCT116 and CT26 cell lines. An in vivo study of HCSD revealed that tumor suppression and site-specific targeted delivery of HCSD nanoparticles in HCT116-xenografted tumors were more superb than in the CT26-xenografted tumor. These results suggest that HCSD nanoparticles can be expected to have high therapeutic efficacy because they enable targeted drug delivery and rapid drug release.

Testing of glutathione contents by calcein-Cu(II) fluorescence spectra

Glutathione (GSH) is a natural active tripeptide formed by glutamic acid, glycine, and cysteine, which plays a vital role in many physiological processes of the living body. The GSH contents of the sample were detected by using calcein-Cu(II) fluorescence system in our work. In a Na2HPO4-NaH2PO4 buffer with a pH of 8.0, Cu (II) could coordinate with calcein. Calcein-Cu(II) complex was not fluorescent which led to a reduction of calcein fluorescence intensity. For the strong affinity of GSH with copper (II), the addition of GSH solution would make calcein free from calcein-Cu(II) complex and recover fluorescence. Excitation spectra and emission spectra of calcein and calcein-Cu(II) system were researched. And fluorescence spectra of calcein-Cu(II) system with different GSH contents were investigated. The influence of experimental parameters such as reaction time and the addition sequence of the solution on results was also studied. We got the following conclusions: first, Cu(II) can make the calcein fluorescence be quenched, but the wavelength at the peak of fluorescence is unchanged. Second, the addition of Glutathione can make the fluorescence of calcein - Cu (II) system recover. And the change of the fluorescence intensity has a linear relationship with the concentration of GSH in the range from 2 × 10−6 to 1.0 × 10−5 mol/l. Third, response time may be extended appropriately for complete reaction in the system. At last, the experimental results have shown that calcein - GSH - Cu(II) system has higher sensitivity and better stability than calcein - Cu(II)- GSH system. This test method is of great importance in practical application.

Flexible TiO2-coated nanocellulose membranes incorporated with CdTe as electrodes in photoelectrochemical cells

Incorporation of quantum dots (QDs) into porous matrices has triggered the development of novel optical devices. In this work, TiO2 sensitized by CdTe incorporated into bacterial nanocellulose (BNC) membranes were tested as photoelectrodes in a photoelectrochemical cell directed to the water splitting for hydrogen generation. The flexible membranes were produced by immersing BNC membranes in an aqueous solution of CdTe capped with glutathione (CdTe–GSH) and further deposited over a thin layer of TiO2. Incorporation of CdTe–GSH into BNC membranes was confirmed by infrared spectroscopy. Fluorescence spectroscopy revealed that the luminescence intensity increased with the immersion time in the CdTe–GSH solution. Field-emission gun scanning electron microscopy (FEG-SEM) images revealed that the CdTe/QDs (5 nm) were homogeneously dispersed on the cellulose nanofibers. BNC/CdTe–GSH membranes was tested as photoelectrodes. Photoelectrochemical cells exhibited a significant photocurrent in wavelengths ranging from 400 to 800 nm, which indicates their potential for applications as flexible electrodes, sensors and photovoltaic systems.

Speciation of reactive sulfur species and their reactions with alkylating agents: do we have any clue about what is present inside the cell?

Buffered aqueous solutions of inorganic, organic, cysteine, GSH and GAPDH polysulfide species were used. Additional experiments in human plasma and serum revealed that monobromobimane can extract sulfide from the endogenous sulfur pool by shifting speciation equilibria, suggesting caution should be exercised when interpreting experimental results using this tool. In the majority of cases, the speciation of alkylated polysulfide/thiol derivatives depended on the experimental conditions. Alkylation perturbed sulfur speciation in both a concentration- and time-dependent manner and strong alkylating agents cleaved polysulfur chains. Moreover, the labelling of sulfenic acids with dimedone also affected cysteine speciation, suggesting that part of the endogenous pool of products previously believed to represent sulfenic acid species may represent polysulfides. We highlight methodological caveats potentially arising from these pitfalls and conclude that current derivatization strategies often fail to adequately capture physiological speciation of sulfur species. This article is part of a themed section on Chemical Biology of Reactive Sulfur Species. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.4/issuetoc.

Fluorescent activatable gadofullerene nanoprobes as NIR-MR dual-modal in vivo imaging contrast agent.

Dual mode imaging technology is widely developed to achieve the early-stage precision cancer diagnosis. Here we designed a dual-modal magnetic resonance/near infrared fluorescence optical imaging contrast agent (GdF-SS-NIR783) with the fluorescence activatable and safer gadofullerene. The nanoprobes were fabricated by conjugating the gadofullerene derivatives with a NIR fluorescence imaging agent (NIR783) via the disulfide bond. The obtained nanoprobes showed no fluorescence (OFF), but the fluorescence turned on when incubated within reduction environment such as GSH solution. The clear fluorescence signal in tumor site was observed obviously after their intratumor injection. The nanoprobes also revealed efficient MRI contrast enhancement both in vitro and in vivo. And they showed good biocompatibility and did not demonstrate any tissue toxicity in vivo. This work gave the new possibility in designing more efficient and safer nanoprobes for future medical diagnoses.

Effects of Glutathione on Hydrolytic Enzyme Activity in the Mouse Hepatocytes.

In this study, the effect of glutathione (GSH) on the activity of hydrolytic enzymes of lysosomal, microsomal, and cytosolic fractions was studied in the mouse hepatocytes. The experiments involved 30 Swiss male mice, divided into the experimental and control groups of 15 mice each. The former group received injections of 12μL/g of GSH solution at a dose of 100μg/g body weight, whereas the latter received 12μL/g of physiological saline, all given intraperitoneally daily for 7days. Then, fragments of liver tissue were collected from the euthanized animals and processed to obtain lysosomal, microsomal, and cytosolic fractions of hepatocytes. The activity of the following enzymes was investigated in vitro: β-glucuronidase, β-galactosidase, β-glucosidase, N-acetyl-hexosaminidase, lysosomal esterase and lipase, acid phosphatase, cathepsin D and L, leucine aminopeptidase, and alanine aminopeptidase. We found that GSH, administered in vivo in the mouse, in the main (73% cases), increased the in vitro activity of the majority enzymes abovementioned, although the effect was somehow variable, depending on the fraction of hepatocytes and the type of enzyme. The findings imply that GSH supplementation may intensify the rate of cellular hydrolytic degradation, i.e., the rate of disposal by the cell of unwanted materials.