Cell signaling promoting protein carbonylation does not cause sulfhydryl oxidation: implications to the mechanism of redox signaling

Reactive oxygen species (ROS) have been recognized as second messengers, however, targeting mechanisms for ROS in cell signaling have not been defined. While ROS oxidizing protein cysteine thiols has been the most popular proposed mechanism, our laboratory proposed that ligand/receptor-mediated cell signaling involves protein carbonylation. Peroxiredoxin-6 (Prx6) is one protein that is carbonylated at 10 min after the platelet-derived growth factor (PDGF) stimulation of human pulmonary artery smooth muscle cells. In the present study, the SulfoBiotics Protein Redox State Monitoring Kit Plus (Dojindo Molecular Technologies) was used to test if cysteine residues of Prx6 are oxidized in response to the PDGF stimulation. Human Prx6 has a molecular weight of 25 kDa and contains two cysteine residues. The Dojindo system adds the 15 kDa Protein-SHifter if these cysteine residues are reduced in the cells. Results showed that, in untreated cells, the Prx6 molecule predominantly exhibited the 55 kDa band, indicating that both cysteine residues are reduced in the cells. Treatment of cells with 1 mM H 2O 2 caused the disappearance of the 55 kDa band and the appearance of a 40 kDa band, suggesting that the high concentration of H 2O 2 oxidized one of the two cysteine residues in the Prx6 molecule. By contrast, PDGF stimulation had no effects on the thiol status of the Prx6 molecule. We concluded that protein carbonylation is a more sensitive target of ROS during ligand/receptor-mediated cell signaling than sulfhydryl oxidation

Observations of the circumstellar water 110 → 110 and ammonia 110 → 00 lines in IRC +10216 by the Odin satellite

Submillimeter lines of H 2O and NH 3 have been detected in the carbon star IRC +10216 (CW Leo) with the Odin submillimeter satellite. The detection of the J K-, K+ = 1 10 → 1 10 557 GHz line of ortho-H 2O confirms the earlier detection in the same source with SWAS. The detection of the J K = 1 0 rarr; 0 0 572 GHz line represents the first observation of the ground-state rotational transition of NH 3 in a stellar envelope. By fitting a molecular line transfer model to the observed lines, we derive an ortho-H 20 abundance of 2.4 × 10 -6, which is consistent with estimates from the SWAS observation. The derived ortho-NH 3 abundance of 1 × 10 -6 relative to H 2 is significantly higher than those derived from 24 GHz inversion transitions and is slightly higher than those from vibrational transitions in the infrared band. The high H 2O and NH 3 abundances in the carbon-rich star IRC+10216 underscore shortcomings in the conventional gas-phase LTE and non-LTE chemical models. © 2006. The American Astronomical Society. All rights reserved.published_or_final_versio

Crosstalk between JNK and SUMO Signaling Pathways: deSUMOylation Is Protective against H2O2-Induced Cell Injury

Background: Oxidative stress is a key feature in the pathogenesis of several neurological disorders. Following oxidative stress stimuli a wide range of pathways are activated and contribute to cellular death. The mechanism that couples c-Jun N-terminal kinase (JNK) signaling, a key pathway in stress conditions, to the small ubiquitin-related modifier (SUMO), an emerging protein in the field, is largely unknown. Methodology/Principal Findings: With this study we investigated if SUMOylation participates in the regulation of JNK activation as well as cellular death in a model of H 2O 2 induced-oxidative stress. Our data show that H 2O 2 modulates JNK activation and induces cellular death in neuroblastoma SH-SY5Y cells. Inhibition of JNK’s action with the D-JNKI1 peptide rescued cells from death. Following H2O2, SUMO-1 over-expression increased phosphorylation of JNK and exacerbated cell death, although only in conditions of mild oxidative stress. Furthermore inhibition of SUMOylation, following transfection with SENP1, interfered with JNK activation and rescued cells from H 2O 2 induced death. Importantly, in our model, direct interaction between these proteins can occur. Conclusions/Significance: Taken together our results show that SUMOylation may significantly contribute to modulation o

Delivery and quantification of hydrogen peroxide generated via cold atmospheric pressure plasma through biological material

The ability of plasma-generated hydrogen peroxide (H 2O 2) to traverse bacterial biofilms and the subsequent fate of the generated H 2O 2 has been investigated. An in vitro model, comprising a nanoporous membrane impregnated with artificial wound fluid and biofilms of varying maturity was treated with a helium-driven, cold atmospheric pressure plasma (CAP) jet. The concentration of H 2O 2 generated below the biofilms was quantified. The results showed that the plasma-generated H 2O 2 interacted significantly with the biofilm, thus exhibiting a reduction in concentration across the underlying nanoporous membrane. Biofilm maturity exhibited a significant effect on the penetration depth of H 2O 2, suggesting that well established, multilayer biofilms are likely to offer a shielding effect with respect to cells located in the lower layers of the biofilm, thus rendering them less susceptible to plasma disinfection. This may prove clinically significant in the plasma treatment of chronic, deep tissue infections such as diabetic and venous leg ulcers. Our results are discussed in the context of plasma-biofilm interactions, with respect to the fate of the longer lived reactive species generated by CAP, such as H 2O

A supramoleculear self-assembled flexible open framework based on the coordination of honeycomb layers possessing octahedral and tetrahedral Co-II geometries

A flexible open framework, {[Co2(L)Cl(DMF)2(H 2O)]??Sx}n (H3L = 4,4???,4??????-[1,3,5-benzenetriyltris(carbonylimino)]-trisbenzoic acid, DMF = dimethylformamide), was constructed based on a honeycomb coordination subunit with both octahedral and tetrahedral CoII sites, showing moderate MeOH sorption and antiferromagnetic properties.close0

Investigation of the H₂O sensing mechanism of DC operated chemiresistors based on graphene oxide and thermally reduced graphene oxide

Graphene oxide (GO) is a promising material for H 2O vapour sensing. However, the H 2O sensing mechanisms are still under investigation especially in the case of thermally reduced GO. To this purpose, planar devices were fabricated by spin-coating graphene oxide on glass substrates. Ultra high response to H 2O was recorded but poor repeatability and stability over time were also noted. Three different degrees of thermal reduction were applied to improve material stability. An inverse change of resistance was observed for reduced graphene oxide compared to pure graphene oxide upon interaction with H 2O. The sensing mechanisms that govern GO and reduced GO behavior were studied based on DC measurements. In the case of GO, strong ionic conductivity was proposed whereas in the case of reduced GO mixed electronic/ionic with the leading mechanism affected by H 2O percentage in air, degree of material reduction, and sensor working temperature. Finally, it was found that by promoting one sensing mechanism over the other, improved operating humidity range of the sensor can be achieved. </p

Efficient synthesis of plate-like crystalline hydrated tungsten trioxide thin films with highly improved electrochromic performance

Plate-like hydrated tungsten trioxide (3WO3·H 2O) films were grown on a fluorine doped tin oxide (FTO) coated transparent conductive substrate via an efficient, facile and template-free hydrothermal method. The film exhibited a fast coloration/bleaching response (tc90% = 4.3 s and tb90% = 1.4 s) and a high coloration efficiency (112.7 cm2 C-1), which were probably due to a large surface area

Dynamic heat of adsorption of water vapour on zeolitic tuff and zeolite 4A by flow microcalorimetry

In this study a practical method for measurement of heat of adsorption of water vapour on adsorbents was developed to evaluate the feasibility of substitution of a zeolitic tuff with zeolite 4A in air drying and heat pumps. The change of heat of adsorption with inlet humidity of the air passing through the calorimeter was investigated. Samples were characterised by X-ray diffraction and thermal gravimetric analysis techniques. Specific heats of the zeolitic tuff and zeolite 4A were measured as 1.01 and 1.42 J/g K, respectively. Adsorption isotherms fitted to the Langmuir model with regression coefficient 0.93 and 0.94 with monolayer capacities, Xm 9.68% and 26.35% H 2O for the zeolitic tuff and zeolite 4A, respectively. The energy storage intensity was measured in the range 48-97 J/g and 464-201 J/g for the tuff and zeolite 4A, respectively. Heat of adsorption of zeolite decreased with surface coverage and it was in the range 1750-2835 and 1104-2640 J/g H 2O for the zeolitic tuff and zeolite 4A, respectively

Electrowetting-Based Digital Microfluidics Platform for Automated Enzyme-linked Immunosorbent Assay

Electrowetting is the effect by which the contact angle of a droplet exposed to a surface charge is modified. Electrowetting-on-dielectric (EWOD) exploits the dielectric properties of thin insulator films to enhance the charge density and hence boost the electrowetting effect. The presence of charges results in an electrically induced spreading of the droplet which permits purposeful manipulation across a hydrophobic surface. Here, we demonstrate EWOD-based protocol for sample processing and detection of four categories of antigens, using an automated surface actuation platform, via two variations of an Enzyme-Linked Immunosorbent Assay (ELISA) methods. The ELISA is performed on magnetic beads with immobilized primary antibodies which can be selected to target a specific antigen. An antibody conjugated to HRP binds to the antigen and is mixed with H 2O 2/Luminol for quantification of the captured pathogens. Assay completion times of between 6 and 10 min were achieved, whilst minuscule volumes of reagents were utilized.Peer reviewe

Realization of the one-dimensional anisotropic XY model in a Tb(III)-W(V) chain compound

We report the magnetic behavior of the one-dimensional (1D) cyanido-bridged chain complex [Tb(pzam) 3(H 2O)M(CN) 8] •H 2O, where M = W(V). The system shows qualitatively similar magnetic behavior with its already reported M = Mo(V): a broad anomaly in the specific heat ascribed to the magnetic interactions, a transition to three-dimensional magnetic order at T C = 1.15 K, and comparable magnetization and susceptibility. However, substituting the Mo(V) ion by the larger W(V) causes a drastic change in the symmetry of the Tb(III) g tensor, whereby the magnetic interaction between the Tb(III) and M(V) changes from Ising type into an anisotropic XY exchange. We analyze the data in terms of theoretical predictions for the 1D XYZ Hamiltonian and we find an excellent agreement between the theory and experimental data (J x = 1.89 K, J y = 2J x, J z = 0). © 2012 American Physical Society.This research was supported by a Veni grant from the Netherlands Organization for Scientific Research (NWO) to S.T.. We acknowledge Spanish MINECO for Grants MAT2009-13977-C03 and CSD2007-00010.Peer Reviewe