Low Concentrations Of Nitric Oxide Research Articles

Quantitative determination of nitric oxide from tissue samples using liquid chromatography—Mass spectrometry

Ever since it was found to mediate the endothelium-dependent dilation of blood vessels, nitric oxide (NO) has generated enormous research interest throughout the biological sciences. Over thirty years of research has identified NO as a ubiquitous and versatile regulatory factor utilized by both vertebrates and invertebrates. The short lifetime and low concentration of NO make quantitation difficult. Here we report a method for measuring NO using the selective reaction with 2-​(4-​carboxyphenyl)-​4,​5-​dihydro-​4,​4,​5,​5-​tetramethyl-1H-​imidazolyl-​1-​oxy-​3-​oxide (carboxy-PTIO) to form carboxy-PTI. We used tandem mass spectrometry to verify the validity of this reaction, and liquid chromatography – mass spectrometry to quantitate the amount of carboxy-PTI formed. Using diethylamine nonoate as a NO donor we demonstrate this method can quantitate NO concentrations with a detection limit of 5 nM. We successfully determined the amount of NO generated endogenously by frog heart/aorta when stimulated by carbachol, a non-selective acetylcholine receptor agonist. Based on these results, we suggest that this technique can be useful for the quantitative determination of NO in biological samples.•We report a method to measure NO by reacting it with carboxy-PTIO to form carboxy-PTI.•The carboxy-PTI is quantified by liquid chromatography mass spectrometry (LCMS).•This method can quantitate NO concentrations ranging from 5 nM to 1 µM

Controlled Nitric Oxide Release Using Poly(lactic-co-glycolic acid) Nanoparticles for Anti-Inflammatory Effects.

Nitric oxide (NO) plays a key role in several physiological functions such as inflammatory responses and immune regulation. However, despite its beneficial functions, the short half-life and diffusion radius limit NO availability in biomedical applications. Hence, controlled release is important to achieve the desired therapeutic effects with exogenous NO delivery. In this study, we fabricated a poly(lactic-co-glycolic acid) (PLGA)-based NO delivery system to release NO in a sustained manner under physiological conditions. To prevent an initial burst release, branched polyethylenimine diazeniumdiolate (BPEI/NONOate), a pH-responsive NO donor, was encapsulated into the hydrophilic core of PLGA nanoparticles. Furthermore, low concentrations of NO released at a consistent level via a stabilization effect obtained as amine groups of BPEI/NONOate interacted with the nearby NONOate. Using the controlled-release profiles, we successfully regulated the inflammatory response in lipopolysaccharide-stimulated peripheral blood mononuclear cells. This work demonstrates the potential of a NO delivery carrier in the regulation of inflammation.

Nitrite-Responsive Hydrogel: Smart Drug Release Depending on the Severity of the Nitric Oxide-Related Disease.

Nitric oxide (NO) is known as one of the most important biomarkers of many diseases. However, the development of NO-triggered drug releasing platforms is challenging due to the low concentration and short lifetime of NO in vivo. In this work, a novel nitrite (NO2-)-responsive hydrogel (DHPL-GEL), which can be used for smart drug release depending on the severity of the NO-related disease, is demonstrated. A dihydropyridine cross-linking agent is designed to construct DHPL-GEL to enable the responsive degradation of the hydrogel triggered by NO2-. On-demand release of the drug loaded in DHPL-GEL was observed under the stimulation of various concentrations of NO2- at the physiological level both in vitro and in vivo. In the inflammatory arthritis rat model, the DHPL-GEL drug delivery system showed a better therapeutic effect and less side effects than the traditional therapy and nonresponsive hydrogel drug delivery system, demonstrating the promising application of the NO2--responsive hydrogel for the treatment of NO-related diseases.

Simultaneous Removal of NO and SO2 with a Novel Oxidation-Absorption Process Based on Air Microbubble Water System

Microbubbles (MBs) can spontaneously generate hydroxyl radicals (·OH) with high oxidizing capacity. In this study, a novel oxidation-absorption process based on a microbubble system in the indirect removal mode was proposed for the simultaneous removal of nitric oxide (NO) and sulfur dioxide (SO2). In this process, an air microbubble water system (AMBW) was produced by a microbubble generator (MBG) inhaling air and tap water and injected into an oxidation-absorption column reactor by the MBG, meanwhile the mixed gas composed of NO and SO2 passed through a micron-sized gas distributor at the bottom of the reactor and flowed into the AMBW. Important parameters including initial pH and temperature of tap water, operation time, NO concentration, SO2 concentration, and NaCl concentration were assessed to investigate the feasibility of the AMBW for the simultaneous removal of NO and SO2. The results showed that ·OH generated from the collapsed MBs played a critical role in the removal and the simultaneous removal of NO and SO2 was successfully achieved with the AMBW. Even with only tap water used as the absorbent, the removal efficiencies of NO and SO2 reached 92.7% and above 99%, respectively, when the experiment conditions were initial water pH 11.5, initial water temperature 298 K, 600 ppm NO, and 3,000 ppm SO2. Compared with the microbubble system in the direct removal mode, this new system is more suitable for the treatment of flue gases with low NO concentration and high volume. Moreover, this novel process should have a good prospect of industrial application in the flue gas treatment due to its high efficiencies of desulfurization and denitration and some advantages such as low usage cost of the reagents, simple system, and small occupation space.

Effect of Nitrosative Stress on the S-Nitroso-Proteome of Paracoccidioides brasiliensis.

The fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the causative agents of paracoccidioidomycosis (PCM), a systemic mycosis endemic to Latin America. This fungus is considered a facultative intracellular pathogen that is able to survive and replicate inside macrophages. The survival of the fungus during infection depends on its adaptability to various conditions, such as nitrosative/oxidative stress produced by the host immune cells, particularly alveolar macrophages. Currently, there is little knowledge about the Paracoccidioides spp. signaling pathways involved in the fungus evasion mechanism of the host defense response. However, it is known that some of these pathways are triggered by reactive oxygen species and reactive nitrogen species (ROS/RNS) produced by host cells. Considering that the effects of NO (nitric oxide) on pathogens are concentration dependent, such effects could alter the redox state of cysteine residues by influencing (activating or inhibiting) a variety of protein functions, notably S-nitrosylation, a highly important NO-dependent posttranslational modification that regulates cellular functions and signaling pathways. It has been demonstrated by our group that P. brasiliensis yeast cells proliferate when exposed to low NO concentrations. Thus, this work investigated the modulation profile of S-nitrosylated proteins of P. brasiliensis, as well as identifying S-nitrosylation sites after treatment with RNS. Through mass spectrometry analysis (LC-MS/MS) and label-free quantification, it was possible to identify 474 proteins in the S-nitrosylated proteome study. With this approach, we observed that proteins treated with NO at low concentrations presented a proliferative response pattern, with several proteins involved in cellular cycle regulation and growth being activated. These proteins appear to play important roles in fungal virulence. On the other hand, fungus stimulated by high NO concentrations exhibited a survival response pattern. Among these S-nitrosylated proteins we identified several potential molecular targets for fungal disease therapy, including cell wall integrity (CWI) pathway, amino acid and folic acid metabolisms. In addition, we detected that the transnitrosylation/denitrosylation redox signaling are preserved in this fungus. Finally, this work may help to uncover the beneficial and antifungal properties of NO in the P. brasiliensis and point to useful targets for the development of antifungal drugs.

Study on the Pollution Characteristics and Sources of Ozone in Typical Loess Plateau City

Ground-level ozone is a secondary pollutant produced by photochemical reactions and it adversely affects plant and human health. Taiyuan City, a typical city on the loess plateau, is suffering from severe ozone pollution. We utilized the data from eight national environmental monitoring sites of Taiyuan, including concentrations of O3 and nitric oxide, and meteorological factors, such as air temperature and wind, to study the pollution characteristics and sources of ozone (O3) in Taiyuan in 2018. Results show that during 2018, the maximum value and 90th percentile of the maximum 8-h running average of O3 concentration were 257 μg/m3 and 192 μg/m3, respectively. There were 72 days where the O3 concentration exceeded the standard in 2018, which were mainly during April to August. The O3 concentration increased from March, reached a high level in April through August, and decreased significantly from September. The O3 concentrations displayed a typical “single peak” diurnal variation, which was high during the day with peak at around 13:00–15:00 and low at night. From April to August, the O3 concentrations at Jinyuan was the highest, followed by Xiaodian and Taoyuan, and the O3 concentrations at Shanglan and Nanzhai were the lowest. When the O3 concentration exceeded the standard value, Jinyuan contributed the most to the O3 pollution of Taiyuan, followed by Taoyuan and Xiaodian. High temperature and pressure, south and southwest winds can lead to an increase in O3 concentration. The O3 pollution in the Taiyuan urban area is caused by local generation, and the transportation of polluted air masses containing oxides of nitrogen (NOx) and volatile organic compounds (VOCs) emitted by industries, such as the coking and steel plants in counties of Jinzhong City in southern Taiyuan, and Qingxu County, and some counties in Lyuliang City to the southwest. In addition, the mountain winds and low nitric oxide concentration are the main reasons for the increase of O3 concentration, often observed in Shanglan at night.

Mild NO preconditioning protects H9c2 cells against NO-induced apoptosis through activation of PI3K/Akt and PKA-dependent pathways

Backgrounds: Nitric oxide (NO) plays a key role in cardioprotection. Its role against cardioprotection is dependent on the level of NO. Although it is well known that NO preconditioning has cardioprotective effects, but its mechanism remains unsatisfactory. Methods: To induce NO preconditioning, H9c2 cells were treated with low NO concentration and subsequently induced apoptosis by high NO. The signalling and anti-apoptotic effects of NO preconditioning were monitored by Western blotting, facs analysis. Results: Sodium nitroprusside (SNP)-induced cytotoxicity was inhibited by low SNP (0.3 mM) preconditioning. Furthermore, low SNP phosphorylated Akt/FoxO1 in the presence of high SNP (1.5 mM), while phosphorylated Akt/FoxO1 and viability were reversed by PI3K inhibitor. Also, low NO-induced CREB phosphorylation with high NO was inhibited by PKA inhibitor, indicating that NO preconditioning protects NO-induced cytotoxicity in PKA dependently. Apoptotic inhibition with NO preconditioning was accompanied with increased Bcl-2, decreased Bax, and caspase3 activation, which was all reversed by LY294002. Conclusion: Our results indicate that low NO preconditioning prevent subsequent high NO-induced apoptosis via Akt/PKA/CREB activation in H9c2 cells.

A comparative study on nitric oxide and hypochlorite as a membrane cleaning agent to minimise biofilm growth in a membrane bioreactor (MBR) process

Reverse osmosis concentrates (ROC) produced from water reclamation plants can threaten the environment if it is not appropriately treated before discharge. A membrane bioreactor (MBR) process to treat ROC was used in this project. In an MBR, fouling is an essential and inevitable phenomenon which leads to higher operational and capital costs. A comparative study on chemical cleaning, such as sodium hypochlorite (NaOCl) and nitric oxide (NO), was experimentally evaluated together with the influence of filtration flux. Exposure to a low concentration of NO reduced biofilms in an MBR system. NO treatment delayed the formation of new biofilm biomass on the membrane. NO also showed good performance in reducing membrane fouling and had no adverse effect on activated sludge and the environment. In MBR, the bacterial community was dominated by Proteobacteria (61%), with Alpha and Beta-proteobacteria representing approximately 54% of the community. After NO treatment, the relative abundance of the Proteobacteria decreased to 44%, and this was also reflected in a reduction in Alpha and Beta-proteobacteria, to 30% and 5% respectively. Thus, NO treatment resulted in the decrease of the relative biofilms associated with reduced MBR performance.

Use of cobalt(II) chelates of monothiol-containing ligands for the removal of nitric oxide.

It is first reported herein that cobalt(II) complexes solution of monothiol-containing multidentate ligands are used to remove low concentration of nitric oxide (NO). These chelating ligands are water-soluble amines, alcohols or acids which containing at least one -SH group, include those of cysteine, mercaptosuccinic acid, mercaptoethanesulfonate, mercaptopropionic acid and the like. These -SH compounds when coordinated with cobalt ions, forming complexes are very effective for NO removal. The results indicate that the side group (methyl, carboxyl, carboxymethyl) on α-carbon atom of ligands contribute to the denitration of the chelate solution, whereas the substituents on sulfur atom of ligands deactivate the complexation system. In addition, we have found that several monothiol compounds with simple molecule structure and low cost exhibit good performance in denitration, and some of cobalt thiol complexes are more valuable in removing NO than ferrous thiol complexes.

Nitric oxide increases biofilm formation in Saccharomyces cerevisiae by activating the transcriptional factor Mac1p and thereby regulating the transmembrane protein Ctr1

BackgroundBiofilms with immobilized cells encased in extracellular polymeric substance are beneficial for industrial fermentation. Their formation is regulated by various factors, including nitric oxide (NO), which is recognized as a quorum-sensing and signal molecule. The mechanisms by which NO regulates bacterial biofilms have been studied extensively and deeply, but were rarely studied in fungi. In this study, we observed the effects of low concentrations of NO on biofilm formation in Saccharomyces cerevisiae. Transcriptional and proteomic analyses were applied to study the mechanism of this regulation.ResultsAdding low concentrations of NO donors (SNP and NOC-18) enhanced biofilm formation of S. cerevisiae in immobilized carriers and plastics. Transcriptional and proteomic analyses revealed that expression levels of genes regulated by the transcription factor Mac1p was upregulated in biofilm cells under NO treatment. MAC1 promoted yeast biofilm formation which was independent of flocculation gene FLO11. Increased copper and iron contents, both of which were controlled by Mac1p in the NO-treated and MAC1-overexpressing cells, were not responsible for the increased biofilm formation. CTR1, one out of six genes regulated by MAC1, plays an important role in biofilm formation. Moreover, MAC1 and CTR1 contributed to the cells’ resistance to ethanol by enhanced biofilm formation.ConclusionsThese findings suggest that a mechanism for NO-mediated biofilm formation, which involves the regulation of CTR1 expression levels by activating its transcription factor Mac1p, leads to enhanced biofilm formation. The role of CTR1 protein in yeast biofilm formation may be due to the hydrophobic residues in its N-terminal extracellular domain, and further research is needed. This work offers a possible explanation for yeast biofilm formation regulated by NO and provides approaches controlling biofilm formation in industrial immobilized fermentation by manipulating expression of genes involved in biofilm formation.

Cross-talk between the Ras GTPase and the Hog1 survival pathways in response to nitrosative stress in Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is a temperature-dependent dimorphic fungus that cause paracoccidioidomycosis (PCM), the major systemic mycosis in Latin America. The capacity to evade the innate immune response of the host is due to P. brasiliensis ability to respond and to survive the nitrosative stress caused by phagocytic cells. However, the regulation of signal transduction pathways associated to nitrosative stress response are poorly understood. Ras GTPase play an important role in the various cellular events in many fungi. Ras, in its activated form (Ras-GTP), interacts with effector proteins and can initiate a kinase cascade. In this report, we investigated the role of Ras GTPase in P. brasiliensis after in vitro stimulus with nitric oxide (NO). We observed that low concentrations of NO induced cell proliferation in P. brasiliensis, while high concentrations promoted decrease in fungal viability, and both events were reversed in the presence of a NO scavenger. We observed that high levels of NO induced Ras activation and its S-nitrosylation. Additionally, we showed that Ras modulated the expression of antioxidant genes in response to nitrosative stress. We find that the Hog1 MAP kinase contributed to nitrosative stress response in P. brasiliensis in a Ras-dependent manner. Taken together, our data demonstrate the relationship between Ras-GTPase and Hog1 MAPK pathway allowing for the P. brasiliensis adaptation to nitrosative stress.

Nitric Oxide Influences HSV-1-Induced Neuroinflammation.

Herpes simplex virus type 1 (HSV-1) has the ability to replicate in neurons and glial cells and to produce encephalitis leading to neurodegeneration. Accumulated evidence suggests that nitric oxide (NO) is a key molecule in the pathogenesis of neurotropic virus infections. NO can exert both cytoprotective as well as cytotoxic effects in the central nervous system (CNS) depending on its concentration, time course exposure, and site of action. In this study, we used an in vitro model of HSV-1-infected primary neuronal and mixed glial cultures as well as an intranasal model of HSV-1 in BALB/c mice to elucidate the role of NO and nonapoptotic Fas signalling in neuroinflammation and neurodegeneration. We found that low, nontoxic concentration of NO decreased HSV-1 replication in neuronal cultures together with production of IFN-alpha and proinflammatory chemokines. However, in HSV-1-infected glial cultures, low concentrations of NO supported virus replication and production of IFN-alpha and proinflammatory chemokines. HSV-1-infected microglia downregulated Fas expression and upregulated its ligand, FasL. Fas signalling led to production of proinflammatory cytokines and chemokines as well as induced iNOS in uninfected bystander glial cells. On the contrary, NO reduced production of IFN-alpha and CXCL10 through nonapoptotic Fas signalling in HSV-1-infected neuronal cultures. Here, we also observed colocalization of NO production with the accumulation of β-amyloid peptide in HSV-1-infected neurons both in vitro and in vivo. Low levels of the NO donor increased accumulation of β-amyloid in uninfected primary neuronal cultures, while the NO inhibitor decreased its accumulation in HSV-1-infected neuronal cultures. This study shows for the first time the existence of a link between NO and Fas signalling during HSV-1-induced neuroinflammation and neurodegeneration.

Stress preconditioning of rooster semen before cryopreservation improves fertility potential of thawed sperm

Avian semen cryopreservation is not as successful as that seen in mammals. This failure is mostly attributed to unique physiological characteristics of poultry semen that make it susceptible to cryo-damages. Utilization of sublethal oxidative stress for preconditioning of sperm, as an innovative approach, improves the cryo-survival of sperm in certain mammalian species. The purpose of this study was to investigate the effects of preconditioning of rooster semen with sublethal oxidative stress [very low concentrations of nitric oxide (NO)] before cryopreservation on the quality and fertility potential of thawed sperm. Semen samples were collected from 20 roosters, twice a wk, and different concentrations of NO [0 (NO-0), 0.01 (NO-0.01), 0.1 (NO-0.1), 1 (NO-1), 10 (NO-10), and 100 μM (NO-100)] were used to investigate the effects of controlled induction of sublethal stress before semen cryopreservation on the thawed sperm performance. A significantly higher (P < 0.05) percentage of total motility was observed in semen treated with NO-1 compared to NO-0, NO-0.01, NO-0.1, NO-10, and NO-100. NO-1 and NO-100 produced the highest and lowest percentages of progressive motility, which were significantly different from that of the other groups (P < 0.05). A significantly higher (P < 0.05) percentage of sperm mitochondria activity was observed in semen exposed to NO-0, NO-0.01, NO-0.1, and NO-1. Moreover, the lowest (P < 0.05) concentration of malondialdehyde (MDA) was measured in samples treated with NO-1 in comparison to the other groups. Abnormal morphology, acrosome integrity, and velocity parameters [velocity average path (VAP) and linearity (LIN)] of sperm were not significantly (P > 0.05) affected by different concentrations of NO. Sperm exposed to NO-1 produced the highest percentage of viable spermatozoa (Annexin-/PI-), which was significantly different from the other samples. Finally, rate of fertility after artificial insemination was significantly higher (P < 0.05) following treatment with NO-1 compared to NO-0 and NO-0.1. Application of 1μM NO as a sublethal oxidative stress before cryopreservation of sperm efficiently increased numerous quality indices of thawed sperm as well as its fertility potential.

Synthesis and detoxification of nitric oxide in the plant beneficial rhizobacterium Bacillus amyloliquefaciens SQR9 and its effect on biofilm formation

Nitric oxide (NO) is an important gas signal that regulates many biological processes, and due to the high nitrogen recycling activity in the rhizosphere, NO is an important signaling molecule in this region. Thus, an understanding of the effect of NO on the rhizomicrobiome, especially on plant beneficial rhizobacteria, is important for the use of these bacteria in agriculture. In this study, the effect of exogenous NO on the beneficial rhizobacterium Bacillus amyloliquefaciens SQR9 was investigated. The results showed that low concentrations of NO increased the ability of the strain SQR9 to form biofilms, while high concentrations of NO inhibited the growth of this bacterium. The SQR9 gene yflM encodes nitric oxide synthase (NOS), which is used to synthesize NO, while the gene ykvO encodes a sepiapterin reductase that is used to synthesize tetrahydrobiopterin, the coenzyme of NOS. Isothermal titration calorimetry and high-performance liquid chromatography analyses demonstrated an interaction between YkvO and NADPH. SQR9 has two hmp genes, although only one was observed to be responsible for NO detoxification through oxidization. This study revealed the effect of NO on plant beneficial rhizobacterium and assessed the ability of this strain to adapt to exogenous NO, which will help to improve the application of this strain in agricultural production.

Experimental investigation of nitric oxide removal from flue gas using hexamminecobalt(II) solution scrubbing in a pilot-scale facility.

An experimental investigation of operational parameters, including liquid/gas ratio (L/G), inlet nitric oxide (NO) concentration, reaction temperature, and pH value of absorbing agent, on NO removal efficiency with hexamminecobalt(II) solution scrubbing was conducted on a pilot-scale facility to search optimal operation conditions. The experimental results show that NO removal efficiency increased with the pH value of hexamminecobalt solution, while the improving rate dropped gradually. When the reaction temperature increased, the NO removal efficiency increased first and then decreased. At the same time, NO removal efficiency increased with the increasing of L/G and hexamminecobalt concentration, while the removal efficiency did not change much at low NO concentration. The pH of 10.4 and L/G of 16 L/m3 were close to the optimal operation conditions, and the scrubbing temperature fell within a reasonable operation temperature. The experimental results can be used as a reference for the design and operation of scaled-up industrial devices.

Soluble guanylate cyclase activation by nitric oxide

Since the discovery of nitric oxide (NO) formation in animals, it has become clear that this toxic, free radical, diatomic gas plays a central role in cellular function in eukaryotes. NO acts as a signaling agent in the cardiovascular system and other tissues. Using a low concentration of NO mitigates the toxicity problem but places a difficult chemical requirement on the NO receptor, the soluble isoform of guanylate cyclase (sGC). sGC contains a heme cofactor that binds and traps NO, thereby activating the enzyme to convert GTP to cGMP. The heme in sGC has unique ligand binding properties enabling sGC to act as a selective receptor for NO. The heme domain of sGC was found to be part of the H-NOX (Heme-Nitric oxide/Oxygen) family of proteins with homologues in both aerobic and anaerobic prokaryotes. Studies with H-NOX proteins has provided a molecular explanation for selective NO trapping at low concentrations. The structure/function picture that is emerging provides new clues to the activation mechanism. It is also become clear that the activation and deactivation of sGC is more complicated than the simple model of NO binding to the heme. As a physiological model is developed it must also account for activity properties of stimulators such as the FDA-approved Adempas®.

The reaction mechanism of plasmonic photocatalytic NO oxidation on Bi-metal/BiPO&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;

With the rapid development of economy, factories and vehicles make the air pollution became a worldwide focused issue. As one of the major air pollutants, nitric oxide (NO) would lead to serious atmospheric problems such as acid rain, haze, and photochemical smog. However, low concentration nitric oxide is hard to be removed by the way of industrialization. Photocatalysis, as a green and effective technology, has become one of the most promising technologies for solving air pollution problems and that works on low concentration air pollutant. As one of the typical photocatalyst, BiPO4 consists of alternating layers of [Bi2O2]2+ and PO43− groups and has the better UV-light photocatalysis performance when compare with TiO2, emerging as an attractive photocatalyst. At present, the study to enable BiPO4 respond visible light which comes up with many ways, such as element doping, build heterojunction and surface hybridization. The recent investigation shows that metal Bi possess the property of surface plasmon resonance (SPR) as well as noble metal like gold could enhance the photocatalysis activity by increasing light absorption and raising the separation efficiency of photogenerated electron-hole pair. In this study, Bi/BiPO4 composite photocatalyst was synthesized via a two steps method. Firstly, the hexagonal phase BiPO4 was prepared by a precipitation method. And then, the metal Bi was deposited on the surface of BiPO4 in the presence of NaBH4. The as-prepared photocatalyst was applied to the photocatalytic removal of low concentration of NO in air. The microstructures of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), UV-visible diffuse-reflectance spectrum (UV-vis DRS) and electron spin-resonance spectroscopy (ESR). The in situ FT-IR was used to analyze the reaction intermediates of photocatalytic NO oxidation under visible light irradiation. On the basis of free radicals capture from ESR, the reaction mechanism was proposed. The results show that the surface plasmon resonance of Bi metal promoted the visible light absorption and separation of photogenerated charge on BiPO4. The DFT calculation results indicated that the presence of oxygen defects induced the formation of the intermediate energy level between the valence band and the conduction band of the bismuth phosphate, which is beneficial to the electron transition from valence band. The results of electronic structure calculations manifest that the metal Bi also plays a role of storing and transferring electrons from the conduction band of BiPO4. The generation and rapid transfer of photogenerated carriers could decrease the photogenerated electron-hole pair recombination rate. As a result, the BiPO4 can be converted into a high performance visible light photocatalyst. The present work could provide new insights into the understanding of the Bi-based plasmonic photocatalyst and the mechanism of gas-phase photocatalytic reaction.

Nitric Oxide Treatment and Induced Genes Role Against Phytophthora infestans in Potato

Effects of sodium nitroprusside (SNP; nitric oxide donor) treatments on enhancement of secondary metabolites production, oxidative stress mediators ( $$\mathrm{O}_{2}^{-}$$ ) accumulation and antioxidant defense enzymes of Potato Spunta Sp. suspension culture cells elicited by a fungal extract from phytophthora infestans mycelium. The obtained data confirmed the significant increase in various oxidative burst (super oxide anion, hydrogen peroxide and total glutathione) contents. The administration of various NO concentrations strongly decreased hydrogen peroxide concentration and superoxide anion levels. Moreover, the SNP treatments regulate elicitor-induced activation of phenylalanine ammonium-lyase and total soluble phenols accumulation. The highest concentrations of NO donor sodium nitroprusside potentiated elicitor-induced H2O2 production. On the other hand, the lowest H2O2 contents coincided with elicitation regulated various activities of enzymes superoxide-dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and Phenyl alanine ammonia lyase (PAL) activity, the decrease in H2O2 concentration was probably due to a direct reduction interaction of NO-H2O2. On the other hand, the addition of these previous NO treatments affects mRNA peroxidase gene expression using RT-PCR techniques. In general, the addition of lower concentrations of nitric oxide reduce the mRNA peroxidase activity on contrary, the higher concentrations induced the mRNA peroxidase activity, which induce the hypersensitive reactions against fungus infection.

Toll-Like Receptor-4 Dependent Inflammatory Responses Following Intestinal Colonization of Secondary Abiotic IL10-Deficient Mice with Multidrug-Resistant Pseudomonas Aeruginosa.

The rising incidences of infections with multidrug-resistant (MDR) Gram-negative bacteria including Pseudomonas aeruginosa (PA) have gained increasing attention in medicine, but also in the general public and global health politics. The mechanisms underlying opportunistic pathogen–host interactions are unclear, however. To address this, we challenged secondary abiotic IL10–/– mice deficient for Toll-like receptor-4 (TLR4–/– × IL10–/–), the main receptor of the Gram-negative cell wall constituent lipopolysaccharide, with a clinical MDR PA isolate. Despite higher intestinal colonization densities, apoptotic colonic epithelial cell numbers were lower in TLR4–/– × IL10–/– mice as compared to IL10–/– controls at day 14 postinfection (p.i.), whereas proliferating/regenerating cells had increased in the latter only. Furthermore, PA-colonized TLR4–/– × IL10–/– mice displayed less distinct innate and adaptive immune cell responses in the colon as compared to IL10–/– counterparts that were accompanied by lower nitric oxide concentrations in mesenteric lymph nodes in the former at day 14 p.i. Conversely, splenic NO levels were higher in both naive and PA-colonized TLR4-deficient IL10–/– mice versus IL10–/– controls. Remarkably, intestinal MDR PA was able to translocate to extra-intestinal including systemic compartments of TLR4–/– × IL10–/– mice only. Hence, MDR PA-induced intestinal and systemic immune responses observed in secondary abiotic IL10–/– mice are TLR4-dependent.

The expression of pluripotency and neuronal differentiation markers under the influence of electromagnetic field and nitric oxide.

Nitric oxide (NO) is a diatomic free radical compound that as a secondary messenger contributes to cell physiological functions and its variations influence proteins activity and triggering intracellular signaling cascades. Low frequency electromagnetic field (EMF) alters the cell biology such as cell differentiation by targeting the plasma membrane and entering force to the ions and small electrical ligands. The effect of these chemical (NO) and physical (EMF) factors on the expression of the stemness and neuronal differentiation markers in rat bone marrow mesenchymal stem cells (BMSC) was investigated. The cells were treated with low (50micromolar) and high (1mM) concentrations of Deta-NO as a NO donor molecule and 50Hz low frequency EMF. The expression of pluripotency and neuronal differentiation genes and proteins was investigated using real time qPCR and Immunocytochemistry techniques. The simultaneous treatment of EMF with NO (1mM) led to the down-regulation of stemness markers expression and up-regulation of neuronal differentiation markers expression. Cell proliferation decreased and cell morphology changed which caused the majority of cells obtains neuronal protein markers in their cytoplasm. The decrease in the expression of neuronal differentiation Nestin and DCX markers without any change in the expression of pluripotency Oct4 marker (treated with low concentration of NO) indicates protection of stemness state in these cells. Treatment with NO demonstrated a double behavior. NO low concentration helped the cells protect the stemness state but NO high concentration plus EMF pushed cells into differentiation pathway.