Free Nitrogen Research Articles

Enolate-Forming Compounds as a Novel Approach to Cytoprotection.

Evidence from laboratory studies and clinical trials suggests that plant-derived polyphenolic compounds such as curcumin, resveratrol, or phloretin might be useful in the treatment of certain diseases (e.g., Alzheimer's disease) and acute tissue injury states (e.g., spinal cord trauma). However, despite this potential, the corresponding chemical instability, toxic potential, and low bioavailability of these compounds could limit their ultimate clinical relevance. We have shown that pharmacophores of curcumin (e.g., 2-acetylcyclopentanone) and phloretin (e.g., 2',4',6'-trihydroxyacetophenone; THA) can provide cytoprotection in cell culture and animal models of oxidative stress injury. These pharmacophores are 1,3-dicarbonyl and polyphenol derivatives, the enol groups of which can ionize in biological solutions to form an enolate. This carbanionic moiety can chelate metal ions and, as a nucleophile, can scavenge toxic electrophiles (e.g., acrolein, 4-hydroxy-2-nonenal, and N-acetyl-p-benzoquinone imine) involved in many pathogenic conditions. Aromatic derivatives such as THA can also trap free oxygen and nitrogen radicals and thereby provide another layer of cytoprotection. The multifunctional character of these enolate-forming compounds suggests an ability to block pathogenic processes (e.g., oxidative stress) at several steps. The purpose of this review is to discuss research supporting our theory that enolate formation is a significant cytoprotective property that represents a platform for development of pharmacotherapeutic approaches to a variety of toxic and pathogenic conditions. Our discussion will focus on mechanism and structure-activity studies that define enolate chemistry and their corresponding relationships to cytoprotection.

Biogas production from chicken manure: Co-digestion with spent poppy straw

Co-digestion of chicken manure (laying hens) and spent poppy straw was investigated in a daily fed laboratory scale mesophilic anaerobic digester. The digester was operated for 240 days and the methane yield was monitored by increasing the organic loading rate (OLR) from 2.78 to 3.56 g VS l−1d−1 and the total ammonia nitrogen (TAN) up to 6650 mg l−1. The highest methane yield of 0.36 l g VS−1 was obtained when the TAN and free ammonia nitrogen (FAN) concentrations were below 4000 and 300 mg l−1, respectively. The results showed that microbial consortia were acclimated to high ammonia concentrations and a methane yield of about 0.28 l g VS−1 was achieved up to 6100 mg l−1of TAN. When the TAN concentration in the digester increased above 6500 mg l−1, the methane yield sharply decreased below 0.14 l g VS−1.

387 - 7-Nitroindazole, Postoperatively Attenuates the 6-OHDA Induced S-Nitrosylation in Rat Model of Parkinson's Disease (PD)

Progressive death of dopaminergic neurons due to the overproduction of highly reactive free reactive oxygen and nitrogen species (ROS/RNS) results in the molecular pathology of PD. Under physiological conditions, reactive free radicals are present at low levels, mediating several neurotrophic and neuroprotective signaling pathways. In contrast, under pathological conditions, there is a pronounced increase in free radical generation, impairing the normal neurological function by undesired S-nitrosylation of many important signaling proteins. S-nitrosylation has been implicated in the pathology of many neurodegenerative diseases including PD. In the present work bilateral 6-OHDA induced rat model had been used to mimic the human pathology and 7-Nitroindazole (7-NI), which has been reported to have neuroprotective effect, was administered postoperatively to evaluate the factual pharmacological effect of 7-NI on 6-OHDA induced S-nitrosylation. The current work demonstrates the differential level of S-nitrosylation of the many physiologically important proteins and the attenuation in the level of S-nitrosylation by 7-NI. Furthermore, our findings have revealed some novel proteins that have not been previously implicated in PD. Maldi-toff analysis identifies following proteins that are differentially S-nitrosylated: GAPDH, Actin, ATP synthase, calreticulin, cyclic nucleotide phosphodiesterase, 14-3-3 gamma, creatine kinase type-B, heat shock cognate 71 kDa protein, 78 kDa glucose regulated protein precursor, and Neurofilament light polypeptide. Among all these proteins GAPDH has been shown to be the mediator of neuronal cell death via translocation of N-cor to the nucleus. The present report suggests that 7-NI acts as efficient neuroprotective agent in 6-OHDA induced rat model by reducing the levels of S-nitrosylation.

ChemInform Abstract: Transition Metal Free Intermolecular Direct Oxidative C—N Bond Formation to Polysubstituted Pyrimidines Using Molecular Oxygen as the Sole Oxidant.

Various polysubstituted pyrimidines are smoothly formed via a base-promoted intermolecular oxidation C–N bond formation of allylic C(sp3)–H and vinylic C(sp2)–H of allyllic compounds with amidines using O2 as the sole oxidant. This protocol features protecting group free nitrogen sources, good functional group tolerance, high atom economy, and environmental advantages.

Synthesis, physicochemical characterization and antibacterial activity of novel (benzoylamino)methyl derivatives of quinolones

Herein we report the synthesis of different derivatives of (fluoro)quinolones norfloxacin, ciprofloxacin and pipemidic acid, by incorporating (benzoylamino)methyl on the free nitrogen of the pyperazinyl moiety. The compounds were structurally characterized by 1D and 2D NMR, FTIR and high-resolution mass spectroscopy. In addition, their physicochemical properties were a matter of interest to be correlated with their structure and antimicrobial activity<em> in vitro</em>. Their antimicrobial activities were screened against Gram-positive, Gram-negative bacteria and <em>C. albicans</em>. Higher distribution coefficients and consequently lower water solubility were determined for all synthesized compounds than the ones of the corresponding leading compounds. Inconsequential correlations between the lipophilicity of the compounds and MIC were observed, suggesting that passive diffusion is not the only mechanism for their penetration into bacterial cells. Further studies are needed to determine how substitutions in the (fluoro)quinolone moiety affect the primary target(s), substrate behavior in respect to bacterial transporters and overall bioavailability.

Dynamic strain aging during wire drawing and its effect on electrochemical behaviour

Second stage dynamic strain aging is observed during cold drawing of low carbon steel wire rods with higher free nitrogen content. The effect is prominent in thinner wires which have experienced higher strain and are thereby heavily stressed. Consequently, these severely deformed wires with higher nitrogen content are prone to early environmental degradation.

Physicochemical properties of bactericidal plasma-treated water

Plasma-treated water (PTW), i.e. distilled water (DW) exposed to low-temperature atmospheric pressure helium plasma, exhibited strong bactericidal activity against Escherichia coli in suspension even within a few minutes of preparation. This effect was enhanced under acidic conditions. The bactericidal activity of PTW was attenuated according to first-order kinetics and the half-life was highly temperature dependent. The electron spin resonance (ESR) signal of an adduct of the superoxide anion radical () was detected in an aqueous solution using a spin-trapping reagent mixed with PTW, and adding superoxide dismutase to the PTW resulted in a loss of the bactericidal activity and weakening of the ESR adduct signal of in the spin-trapping. These results suggest that plays an important role in imparting bactericidal activity to PTW. Moreover, molecular nitrogen was required both in the ambient gas and in the DW used to prepare the PTW. We, therefore, suggest that the reactive molecule in PTW with bactericidal effects is not a free reactive oxygen species but nitrogen atom(s)-containing molecules that release , such as peroxynitrous acid (ONOOH) or peroxynitric acid (O2NOOH). Considering the activation energy for degradation of these species, we conclude that peroxynitric acid stored in PTW induces the bactericidal effect.

Genetic analysis of grain and malt quality in an elite barley population

Quantitative trait loci (QTLs) associated with grain weight, grain width, kernel hardness and malting quality were mapped in a doubled haploid population derived from two elite Australian malting barley varieties, Navigator and Admiral. A total of 30 QTLs for grain weight, grain width and kernel hardness were identified in three environments, and 63 QTLs were identified for ten malting quality traits in two environments. Three malting quality traits, namely β-amylase, diastatic power and apparent attenuation limit, were mainly controlled by a QTL linked to the Bmy1 gene at the distal end of chromosome 4H encoding a β-amylase enzyme. Six other malting quality traits, namely α-amylase, soluble protein, Kolbach index, free amino-acid nitrogen, wort β-glucan and viscosity, had coincident QTL clustered on chromosomes 1HS, 4HS, 7HS and 7HL, which demonstrated the interdependence of these traits. There was a strong association between these malt quality QTL clusters on chromosomes 1HS and 7HL and the major QTL for kernel hardness, suggesting that the use of this trait to enable early selection for malting quality in breeding programs would be feasible. In contrast, the majority of QTLs for hot-water extract were not coincident with those identified for other malt quality traits, which suggested differences in the mechanism controlling this trait. Novel QTLs have been identified for kernel hardness on chromosomes 2HL and 7HL, hot-water extract on 7HL and wort β-glucan on 6HL, and the resulting markers may be useful for marker-assisted selection in breeding programs.

Sources of Reactive Oxygen and Nitrogen Species in Tissue Microenvironment of Hernioplasty Materials.

Titanium and polypropylene mesh endoprostheses were implanted into the rat abdominal cavity and the populations of cells migrating to their surface were analyzed. On both materials, the cells were presented mainly by macrophages that proliferated, activated, and fused to form multinuclear cells. Contact with the foreign surface triggered superoxide anion generation and myeloperoxidase synthesis by macrophages (these processes were more intense on polypropylene implants than on titanium ones) and stimulated production of nitric oxide by macrophage. It was hypothesized that the effects of free nitrogen and oxygen radicals lead to oxidation and destruction of the polypropylene endoprosthesis surface.

Effects of pungency degree on mesophilic anaerobic digestion of kitchen waste

This study investigated the influence of pungency degrees (PDs) on mesophilic anaerobic digestion of kitchen waste (KW). Batch tests were performed to evaluate the methane potential and production rate and the effect of PDs on organics degradation efficiency (in terms of volatile solids, protein and ether extract) at mesophilic temperature. Koch and Drewes model and modified Gompertz model were applied to assess the effects of PDs on the hydrolysis rate constant, biomethane yield rate and lag time. The results revealed that with the increasing contributions of PDs, the methane yield, organics degradation efficiency and hydrolysis rate of KW decreased while the pH values and concentrations of total ammonia nitrogen and free ammonia nitrogen were increased. Additionally, PDs lower than PD3 presented better digestion performance, and according to results of organics degradation and kinetics study, it could be suggested that appropriate range of PD in KW beneficial for AD is PD5–PD4.

Enhanced germination of barley (Hordeum vulgare L.) using chitooligosaccharide as an elicitor in seed priming to improve malt quality.

To study enhanced barley germination by chitooligosaccharide as an elicitor for improving the quality of malt. Barley germination for both radical and leaf sprouts was enhanced when chitooligosaccharide was added to the steeping water in the first steeping cycle. The activities of hydrolases (α-/β-amylase, proteinase and β-glucanase) and antioxidases (superoxide dismutase and catalase) in the resultant malt were increased in a dose-dependent manner when chitooligosaccharide was supplemented in the steeping water. Maximal promotion was at 1 mg chitooligosaccharide/l for α-/β-amylase and proteinase, and at 10 mg/l for β-glucanase, superoxide dismutase and catalase. Malt quality, including free α-amino nitrogen content, Kolbach index, malt extract content, diastatic power, wort viscosity and the ratio of glucose, maltose and maltotriose, was significantly improved by chitooligosaccharide in seed priming at 1 mg/l. Application of chitooligosaccharide in the steeping water promotes barley germination and improves the quality of malt.

Modeling plasma-assisted methane–air ignition using pre-calculated electron impact reaction rates

Development of practical combustion applications implementing plasma-assisted ignition technology for improved efficiency or fuel versatility will benefit from computationally-feasible models which include the plasma processes governing experimentally-observed combustion enhancement. A detailed chemical kinetic reaction mechanism for methane combustion with relevant plasma reactions has been compiled, including a set of electron impact cross sections for elastic and inelastic collisions with reactants, intermediate species, and products of methane combustion. In addition to electron impact reactions, the present mechanism includes reactions involving vibrationally- and electronically-excited species, dissociative recombination reactions, three-body recombination reactions, charge transfer reactions, and relaxation reactions, taken from the literature where available, and otherwise calculated using published correlations. While many past mechanisms have made assumptions limiting their use to specific regimes such as nanosecond discharges or microwave-enhanced flames, the present mechanism is generalized to include kinetics relating to both high- and low-energy excitation. The chemical kinetic mechanism is designed for use in a two-temperature chemical kinetics solver that tracks the electron temperature in addition to the gas temperature, as non-thermal plasma regimes characteristic to plasma-assisted combustion will typically have electron energies out of equilibrium with the energy of the heavier gas particles. Analysis considers the effects of initial temperature, mixture composition, electron concentration, and electric field strength on plasma ignition effectiveness. As commonly practiced, costly calculation of the Boltzmann equation at every time step is avoided by pre-calculating electron impact reaction rate coefficients using a Boltzmann equation solver. Here we evaluate the pre-calculated rates assumption, showing that ignition predictions depend on the gas composition at which the electron impact reaction rates are generated, but that induced errors are acceptable given the uncertainty in other model parameters such as impact cross sections. Finally, chemical kinetic sensitivity analysis highlights the importance of reactions governing free charge balance and nitrogen vibrational excitation when plasma effects on combustion enhancement are strong.

Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

Abstract High nitrogen stainless steel (HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance. Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poor mechanical properties. The above problems can be overcome by proper selection and procedure of joining process. In the present work, an attempt has been made to correlate the microstructural changes with mechanical properties of fusion and solid state welds of high nitrogen steel. Shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), electron beam welding (EBW) and friction stir welding (FSW) processes were used in the present work. Optical microscopy, scanning electron microscopy and electron backscatter diffraction were used to characterize microstructural changes. Hardness, tensile and bend tests were performed to evaluate the mechanical properties of welds. The results of the present investigation established that fully austenitic dendritic structure was found in welds of SMAW. Reverted austenite pools in the martensite matrix in weld zone and unmixed zones near the fusion boundary were observed in GTA welds. Discontinuous ferrite network in austenite matrix was observed in electron beam welds. Fine recrystallized austenite grain structure was observed in the nugget zone of friction stir welds. Improved mechanical properties are obtained in friction stir welds when compared to fusion welds. This is attributed to the refined microstructure consisting of equiaxed and homogenous austenite grains.

Abstract 3459: Effects of Dehydroepiandrosterone (DHEA) treatment on serum methylation, oxidative and nitrosative stress biomarkers in an obesity model of mammary carcinogenesis

Abstract Free oxygen and free nitrogen radicals, commonly named as reactive oxygen species (ROS) and reactive nitrogen species (RNS) play an important role in cancer promotion. The cumulative effect of ROS/RNS termed oxidative and nitrosative stress is commonly seen in the development of several cancers. Obesity has been also linked with the risk of development of various cancers, including breast cancer. DHEA is a dietary supplement used as an anti-cancer agent and anti-obesity supplement. Previously, we reported that obese rats fed DHEA had lower body weight gain and developed no mammary tumor in DMBA model. The effect of DHEA on development of oxidative/nitrosative stress is not known. The objectives of this study were to investigate the possible mechanism of DHEA tumor protection by determining the DHEA effects on serum concentration of methylation cycle metabolites, oxidative and nitrosative stress biomarkers. Twenty (20) six-week-old obese female Zucker rats were randomly assigned ad libitum to water and a diet of either chow as a control diet or chow with the addition of DHEA at a concentration of 6 g/kg of chow as a DHEA diet. All rats were orally gavaged at age 50 days with 65 mg DMBA/kg body weight and were sacrificed 155 days later. Serum concentration of Methionine, S-sdenosylmethionine (SAM), S-adenosylhomocysteine (SAH), homocysteine, free reduced glutathione (fGSH), oxidized glutathione (GSSG), nitroglutathione (GSNO), free Cysteine, Cystine and 3-nitroTyrosine (3NT) were measured by HPLC method with electrochemical detection or LC-MS method. There were no significant differences in serum concentration of fGSH between control and DHEA fed-rats. However, DHEA-fed rats had lower (P<0.03) serum concentration of GSSG which led to higher (P<0.02) glutathione “intracellular oxidative ratio” (fGSH/GSSG) compared to control rats. Despite higher (P<0.004) serum concentration of free Cysteine in control rats, DHEA-fed rats had lower (P<0.04) serum concentration of Cystine (P<0.003) compared to control rats which led to a lower (P<0.04) Cystine/fCysteine “extacellular oxidative ratio”. Concentration of biomarkers for “nitrosative stress” were lower for 3NT (P<0.04) and GSNO (P<0.02) in serum of DHEA-fed rats compared to control rats. Also, DHEA-fed rats had a lower (P<0.02) Methionine concentration which was accompanied with increased serum SAM concentration (P<0.005) and lower (P<0.02) concentration of SAH and homocysteine (P<0.03) compared to control rats. These changes lead to an increase (P<0.0001) in SAM/SAH “methylation ratio” in DHEA-fed rats compared to control rats. In summary, our results suggest that DHEA fed-rats are capable of reducing body weight gain and protecting mammary tumors formation by improving “methylation environment conditions” and decreasing damaging effect oxidative and nitrosative stress. Supported by ABI and ACHRI to RH and SM. Citation Format: Reza Hakkak, Soheila Korourian, Teresa Evans, Oleksandra Pavliv, Stepan Melnyk. Effects of Dehydroepiandrosterone (DHEA) treatment on serum methylation, oxidative and nitrosative stress biomarkers in an obesity model of mammary carcinogenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3459.

Lithium Sulfondiimidoyl Carbanions

The trapping of sulfondiimine-based α-lithiated carbanions with aldehydes leads to unprecedented β-hydroxy sulfondiimines in good yields. An alkylation has been achieved by treatment of the metalated species with methyl iodide. Of special interest, N-monosubstituted β-hydroxy sulfondiimines can be accessed without protection of the free nitrogen.

Determination of free nitrogen in carbon steels by inert gas fusion method

The possibility to use hot extraction (thermal extraction in a carrier-gas flow) for fractional analysis of nitrogen in carbon steels is shown for cord and reinforcing-bar steels. A rapid procedure is developed for an analysis of free nitrogen in carbon steels. The validity of the analytical procedure is confirmed by high-temperature hydrogen extraction. The data obtained by the two methods correlate well with each other. A sample preparation procedure is developed for the determination of the content of dissolved nitrogen.

HIGH TEMPERATURE GAS NITRIDING TREATMENT OF AISI 430 USING LOW AND HIGH PURITY NITROGEN GAS

The properties of stainless steels can be improved by high temperature gas nitriding (HTGN) treatment. The improving of their properties are obtained from nitrogen atom which diffuse into stainless steel. Nitrogen gas is the main source of nitrogen atom on the HTGN treatment. Generally, these treatment use high purity of nitrogen gas. The aim of this research is to investigate the effect of nitrogen gas purity on the HTGN treatment for AISI 430. Stainless steel AISI 430 plate 2 mm thick was processed by HTGN treatment. The specimens was exposed at nitrogen gas atmosphere at temperature 1200oC and held for 2 hours prior quenching in water. The treatment used industrial/welding grade (99.5%) as low nitrogen gas purity and ultra high purity (UHP) grade (99.999%) as high nitrogen gas purity. The vickers micro-hardness test was conducted to evaluate the hardness distribution from surface into middle section of the specimens before and after treatment. Light optical microscope was applied to examine the microstructure of specimens after treatment. Metallographic examination shows both treatments using low and high purity gas have the same grain size. However HTGN treatment using low purity of nitrogen gas produces hardness slightly lower than the high purity. This is due the high content of impurity of the low purity gas that reduces the partial pressure of nitrogen gas. Another effect of impurity is the reaction between nitrogen gas and its impurity especially oxygen gas. These reactions reduce the amount of free nitrogen atom which diffuses on the stainless steel.

Transition Metal Free Intermolecular Direct Oxidative C-N Bond Formation to Polysubstituted Pyrimidines Using Molecular Oxygen as the Sole Oxidant.

Various polysubstituted pyrimidines are smoothly formed via a base-promoted intermolecular oxidation C-N bond formation of allylic C(sp(3))-H and vinylic C(sp(2))-H of allyllic compounds with amidines using O2 as the sole oxidant. This protocol features protecting group free nitrogen sources, good functional group tolerance, high atom economy, and environmental advantages.

Metabolic processes of Methanococcus maripaludis and potential applications.

Methanococcus maripaludis is a rapidly growing, fully sequenced, genetically tractable model organism among hydrogenotrophic methanogens. It has the ability to convert CO2 and H2 into a useful cleaner energy fuel (CH4). In fact, this conversion enhances in the presence of free nitrogen as the sole nitrogen source due to prolonged cell growth. Given the global importance of GHG emissions and climate change, diazotrophy can be attractive for carbon capture and utilization applications from appropriately treated flue gases, where surplus hydrogen is available from renewable electricity sources. In addition, M. maripaludis can be engineered to produce other useful products such as terpenoids, hydrogen, methanol, etc. M. maripaludis with its unique abilities has the potential to be a workhorse like Escherichia coli and S. cerevisiae for fundamental and experimental biotechnology studies. More than 100 experimental studies have explored different specific aspects of the biochemistry and genetics of CO2 and N2 fixation by M. maripaludis. Its genome-scale metabolic model (iMM518) also exists to study genetic perturbations and complex biological interactions. However, a comprehensive review describing its cell structure, metabolic processes, and methanogenesis is still lacking in the literature. This review fills this crucial gap. Specifically, it integrates distributed information from the literature to provide a complete and detailed view for metabolic processes such as acetyl-CoA synthesis, pyruvate synthesis, glycolysis/gluconeogenesis, reductive tricarboxylic acid (RTCA) cycle, non-oxidative pentose phosphate pathway (NOPPP), nitrogen metabolism, amino acid metabolism, and nucleotide biosynthesis. It discusses energy production via methanogenesis and its relation to metabolism. Furthermore, it reviews taxonomy, cell structure, culture/storage conditions, molecular biology tools, genome-scale models, and potential industrial and environmental applications. Through the discussion, it develops new insights and hypotheses from experimental and modeling observations, and identifies opportunities for further research and applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0500-0) contains supplementary material, which is available to authorized users.

Effect of Starter Culture Addition and Processing Method on Proteolysis and Texture Profile of Traditional Dry-Fermented Sausage Petrovská klobása

Proteolysis and texture profile of Petrovská klobása, made with addition of starter culture, were investigated during the ripening in different conditions (traditional versus industrial). Due to intensive degradation of myofibrillar proteins, significant increases of non-protein nitrogen and free amino acids nitrogen contents were registered in all samples. Similar proteolytic changes were found in both starter and non-starter sausages, but were more pronounced in samples ripened in industrial room. In relation to ripening conditions hardness and chewiness differed significantly, while starter culture had significant effect only on hardness of sausages processed in industrial room.