Nitrogen Compounds Research Articles

The network interactions between the porcine deltacoronavirus nucleocapsid protein and host cellular proteins

Porcine deltacoronavirus (PDCoV) is an emerging swine coronavirus that can cause diarrhea in pigs of all ages with varying severity. Host–virus protein interactions are critical for intracellular viral replication. Elucidating the interactions between cellular and viral proteins can help us to design antiviral strategies. PDCoV N protein is the most abundant and vital regulator in virus replication. In this study, 604 host proteins were identified to interact with PDCoV N protein by Co-IP combined with LC-MS, of which 243 proteins were specifically bound to N protein. PPI analysis revealed that the N-interacting host proteins are categorized into three groups: ribonucleoprotein complex biogenesis modulation, cellular nitrogen compound metabolism, and nucleic acid binding. GO and KEGG analyses showed that the host proteins are primarily involved in mRNA splicing, stress granule assembly, spliceosomal snRNP assembly. Additionally, four host proteins-TRIM25, HNRNPUL1, RPS27A, and SLC3A2-were selected to validate the interactome data through Co-IP and Confocal assays. This study can help in designing anti-PDCoV strategies and understanding the replication mechanism of PDCoV.

Elaborating the Atmospheric Transformation of Combined and Free Amino Acids From the Perspective of Observational Studies

AbstractProteinaceous matter (PrM) is a substantial component of bioaerosols. Although numerous studies have examined the characteristics and sources of PrM in the atmosphere, its interactions with atmospheric oxidants remain uncertain. A 1‐year observation of PrM characteristics in PM2.5 was performed in both urban Nanchang (eastern China) and suburban Guiyang (southwestern China), respectively. Glycine was the dominant free amino acid (FAA) species in urban Nanchang. In contrast, proline dominated both total free amino acids (FAAs) and total combined amino acids (CAAs) in suburban Guiyang. We found that oxidative degradation can significantly promote the release of FAAs, especially glycine, from CAAs in Nanchang. The controlled experiment on protein oxidation by hydroxyl radical suggested that the contribution of free glycine to the total FAA fraction tended to increase during the oxidative degradation of CAAs, supporting the predominance of glycine in FAAs in Nanchang and most previous observations. The composition of FAAs was mainly influenced by primary sources in suburban Guiyang with weak atmospheric degradation of PrM. These results suggest that the degradation of aerosol PrM by atmospheric oxidants can be responsible for the difference in FAA composition between the biosphere and the atmosphere, and also imply that the oxidative degradation of aerosol PrM may be a potential source of secondary organic nitrogen compounds in aerosols. Thus, this study can improve the current understanding of the composition characteristics of PrM in the biosphere and the atmosphere, as well as the liquid phase reactions of proteinaceous compounds with atmospheric oxidants.

Application of natural zeolite adsorption in cooperation with photosynthesis for the post-treatment of microbial fuel cells.

Microbial fuel cells (MFCs) are a promising technology that directly converts organic matter (OM) in wastewater into electricity while simultaneously degrading contaminants. However, MFCs are insufficient for the removal of nitrogenous compounds. Therefore, the post-treatment of MFCs is essential. This study was the first to use natural zeolite adsorption integrated with photosynthesis (ZP) for post-treating MFCs. In this system, no external energy was required; instead, natural light was used to promote the growth of photosynthetic microorganisms, thereby enhancing contaminants removal through the photosynthesis process. To assess the effectiveness of the method, comparisons were conducted under two conditions: dark (no photosynthesis) and light (with photosynthesis). In darkness, extending hydraulic retention time (HRT) enhanced COD and BOD removal by 19.8% and 28.9%, respectively. When exposed to natural light, improvements were even more notable, with COD and BOD removal reaching 32% and 40%, respectively. In both conditions, the method effectively removed NH4 +, achieving 60% efficiency in darkness and 84.5% in light. This study showed that the adsorption capacity of the zeolite reached saturation when the cumulative liquid volume per unit weight of the zeolite exceeded 0.2 L g-1. The key functional photosynthetic microbes were investigated using 16S rRNA and 18S rRNA. This revealed the presence of microorganisms such as Chlorobium, Acidovorax, Novosphingobium, and Scenedesmus, which likely play a role in enhancing the efficiency of photosynthesis in removing contaminants. The study findings indicated that the integration of MFCs-ZP represents an eco-friendly approach capable of resource recovery from wastewater while also meeting discharge standards.

New compound XeN14 with high energy density

As a high-energy density material, polymeric nitrogen has attracted considerable attention, while the exceptionally high synthesis pressure hinders its studies and applications. A significant discovery indicates that the insertion of noble gas elements can effectively reduce the synthesis pressure of polymeric nitrogen compounds. This work utilized the particle swarm optimization algorithm and first-principles calculations to extensively explore the stoichiometry of Xe–N compounds under high pressures. Two phases of XeN14, P6mm and P-62m, have been discovered, which are energetically more stable than the basic mixture of Xe and N2. Evidence of charge transfer between Xe and N was found, verifying that Xe plays a crucial role in forming polymeric nitrogen compounds. These two compounds are kinetically stable at pressures ranging from 50 to 200 GPa and exhibit semiconductor properties. A unique channel-like structure was discovered in the P6mm phase. The energy densities of P6mm and P-62m phases are 7.39 and 7.59 kJ/g, respectively, significantly exceeding those of TNT (Trinitrotoluene) and HMX (Octogen), indicating their potential as high-energy density materials.

Growth of complete ammonia oxidizers on guanidine

Guanidine is a chemically stable nitrogen compound that is excreted in human urine and is widely used in manufacturing of plastics, as a flame retardant and as a component of propellants, and is well known as a protein denaturant in biochemistry1–3. Guanidine occurs widely in nature and is used by several microorganisms as a nitrogen source, but microorganisms growing on guanidine as the only substrate have not yet been identified. Here we show that the complete ammonia oxidizer (comammox) Nitrospira inopinata and probably most other comammox microorganisms can grow on guanidine as the sole source of energy, reductant and nitrogen. Proteomics, enzyme kinetics and the crystal structure of a N. inopinata guanidinase homologue demonstrated that it is a bona fide guanidinase. Incubation experiments with comammox-containing agricultural soil and wastewater treatment plant microbiomes suggested that guanidine serves as substrate for nitrification in the environment. The identification of guanidine as a growth substrate for comammox shows an unexpected niche of these globally important nitrifiers and offers opportunities for their isolation.

Effects of dietary replacement of fishmeal by defatted Tenebrio molitor meal, Clostridium autoethanogenum protein meal and Chlorella vulgaris meal on the freshness of turbot (Scophthalmus maximus) during chilled storage

The present work evaluated the effects of dietary fishmeal replacement with three non-food protein sources, including defatted Tenebrio molitor meal (TM), Clostridium autoethanogenum protein meal (CAP) and Chlorella vulgaris meal (CV), on the freshness traits of turbot Scophthalmus maximus. TM, CAP, or CV were used to respectively replace 0 %, 15 %, 30 %. 45 %, 60 % and 75 % of dietary fishmeal protein. Turbot (180.5 ± 2.5 g) were fed with eighteen experimental diets for 70 days, and were stored at 4 ℃ for 3 days. TM and CAP linearly increased QIM scores, but no obvious trend between QIM scores and CV dietary level. The TM15 diet decreased the QIM score, indicating better overall freshness compared to the other TM-groups. Chromameter indicated that consumers could not distinguish the color differences among groups (ΔE < 3). The muscle hardness of all groups was significantly reduced after storage (P<0.05), except the fish fed TM15 diet. Moreover, the TM15 group showed lower pH, TVB-N, and TBA levels after storage, whereas higher TM replacement levels (>30 %) resulted in increased pH, TVB-N, and TBA levels compared with the fish fed TM0 diet. But cathepsin B and L activities showed no significant differences across all TM-groups. Among the CAP-groups, no significant differences were noted in pH and TBA levels; however, CAP linearly increased TVB-N levels after storage. CV did not significantly influence the post-storage pH, TVB-N, and TBA levels. The muscle glycogen content showed no significant variance among the groups. In conclusion, a 15 % dietary replacement of fishmeal with TM optimized the freshness of turbot by decelerating muscle softening, lipid oxidation, and the production of volatile nitrogen compounds, whereas higher levels of TM accelerated these processes. CAP replacement level exceeding 15 % enhanced the production of volatile nitrogen compounds. Dietary inclusion of CV did not impact the freshness of turbot during storage.

Bacterial ecology and evolution converge on seasonal and decadal scales.

Ecology and evolution are often viewed as distinct processes, which interact on contemporary time scales in microbiomes. To observe these processes in a natural system, we collected a two-decade, 471-sample freshwater lake time series, creating the longest metagenome dataset to date. Among 2,855 species-representative genomes, diverse species and strains followed cyclical seasonal patterns, and one in five species experienced decadal shifts in strain composition. The most globally abundant freshwater bacterium had constant species-level abundance, but environmental extremes appeared to trigger a shift in strain composition and positive selection of amino acid and nucleic acid metabolism genes. These genes identify organic nitrogen compounds as potential drivers of freshwater responses to global change. Seasonal and long-term strain dynamics could be regarded as ecological processes or equivalently as evolutionary change. Rather than as distinct processes that interact, we propose a conceptualization where ecology and evolution converge along a continuum to better describe change in diverse microbial communities.

Component Composition and Features of Biological Activity of Viscum album (Viscaceae).

The review summarizes the data on the chemical composition and some features of biological activity of the European mistletoe Viscum album L. (Viscaceae Batsch). Among secondary metabolites, viscotoxins, lectins, carbohydrates, amino acids, flavonoids, triterpene acids, and nitrogenous compounds predominate in V. album. Mistletoe extracts and their indivdiual components exert various biological activities, including antitumor, immunomodulatory, and antidiabetic activities, and improve cognitive functions.

Role of nitrogen and silver compounds in photocatalytic properties of carbon nanoparticle

To develop the photocatalytic method of water decontamination in an industrial scale, the structure of the photocatalyst should be modified in order to work under visible light irradiation. This paper is a report on a comparison of the efficiency of the photocatalytic activity of carbon, carbon nitride (CN) and carbon-silver (CAg) nanostructures for the degradation of Methylthioninium chloride in water. Carbon nanoparticles were synthesized by pulsed laser ablation (PLA) of a graphite target in distilled water. To synthesize CN nanocomposite, carbon nanoparticles were placed in normal pressure nitrogen-filled oven at 700 °C for 5 h. And to synthesize the CAg nanocomposite, bulk silver was ablated in the carbon nanoparticles solution by pulsed laser. Degradation was examined in dark condition and under the UV and visible light irradiations. Results show that the efficiency of photocatalytic activity of carbon dots as an abundant nanomaterial was increased, by their modification through atomic substitution (carbon nitride) and alloying (carbon-silver). Results show that the chemical properties of CN made this nanocomposite have the best performance among the 3 nanomaterials in dark and UV irradiated conditions, while the plasmonic absorption of silver nanoparticles made this material to have the best photocatalytic performance under visible light irradiation.

Performance of a Ship-Based Cupronickel Alloy in Exposure Conditions of Arabian Seawater-A Comparative Study.

Cupronickel-based alloys are widely known for their excellent resistance against aqueous corrosion, however, they can be susceptible to corrosion at accelerated rates and premature failure when exposed to a polluted or brackish seawater medium, even for short-term exposure durations. This unfamiliar corrosion behavior may be a result of the formation of an unprotected corrosion film during the early exposure durations. The paper investigates the corrosion phenomenon in cupronickel 90/10 alloy, by exposing the coupons in two different seawater compositions in the Arabian Sea region. Corrosion losses were investigated on the experimental coupons in a submerged position, for a maximum exposure duration of 150 days, using the conventional weight loss method and a new dimensional metrology-based measurement technique. Additionally, in this research the tubes of a marine heat exchanger having similar material that failed prematurely during operation in the Arabian Sea were also investigated for corrosion losses, followed by the characterization of the corrosion deposits using following analytical techniques: SEM, EDS, XRD and Raman Scattering. The experimental results showed significantly higher corrosion losses on coupons exposed to seawater site rich in pollutants and nutrients including dissolved inorganic nitrogenous compounds, compared to those subjected to a natural seawater solution in corrosion tanks maintained in a controlled environment.

Biofuel from wastewater-grown microalgae: A biorefinery approach using hydrothermal liquefaction and catalyst upgrading

Third-generation biofuels from microalgae are becoming necessary for sustainable energy. In this context, this study explores the hydrothermal liquefaction (HTL) of microalgae biomass grown in wastewater, consisting of 30% Chlorella vulgaris, 69% Tetradesmus obliquus, and 1% cyanobacteria Limnothrix planctonica, and the subsequent upgrading of the produced bio-oil. The novelty of the work lies in integrating microalgae cultivation in wastewater with HTL in a biorefinery approach, enhanced using a catalyst to upgrade the bio-oil. Different temperatures (300, 325, and 350 °C) and reaction times (15, 30, and 45 min) were tested. The bio-oil upgrading occurred with a Cobalt-Molybdenum (CoMo) catalyst for 1 h at 375 °C. Post-HTL, although the hydrogen-to-carbon (H/C) ratio decreased from 1.70 to 1.38–1.60, the oxygen-to-carbon (O/C) ratio also decreased from 0.39 to 0.079–0.104, and the higher heating value increased from 20.6 to 36.4–38.3 MJ kg−1. Palmitic acid was the main component in all bio-oil samples. The highest bio-oil yield was at 300 °C for 30 min (23.4%). Upgrading increased long-chain hydrocarbons like heptadecane (5%), indicating biofuel potential, though nitrogenous compounds such as hexadecanenitrile suggest a need for further hydrodenitrogenation. Aqueous phase, solid residues, and gas from HTL can be used for applications such as biomass cultivation, bio-hydrogen, valuable chemicals, and materials like carbon composites and cement additives, promoting a circular economy. The study underscores the potential of microalgae-derived bio-oil as sustainable biofuel, although further refinement is needed to meet current fuel standards.

Universal intumescent polyelectrolyte complex treatment for cotton, polyester, and blends thereof

Inhibiting the flammability of natural, synthetic, and blended textiles with a single treatment is challenging because of differing fiber properties and chemistries. Intumescent surface treatments that promote char formation can be applied in the form of a polyelectrolyte complex (PEC) containing nitrogen and phosphorus compounds that combat burning in both the condensed and gas phase. Poly(allylamine hydrochloride) (PAH) and poly(sodium phosphate) (PSP) comprise a PEC that reduces the flammability of cotton, polyester, and polyester/cotton (PECO). The incorporation of melamine renders each substrate self-extinguishing. The degradation of PAH is seen to differ between substrates, with gas phase degradation being more prevalent on polyester and heterocyclization occurring on cellulose. Quantitatively, cotton flammability is reduced more than that of polyester, but significant improvements are made to the char yield, heat release, and volatile emission for all fabric types. This water-based coating is rapidly applied in two steps for fire protection. These results demonstrate the versatility of PEC coatings as environmentally-benign fire protection for a variety of chemistries.

Engineering a dysbiotic biofilm model for testing root caries interventions through microbial modulation

BackgroundThis study aimed to engineer and optimise a dysbiotic biofilm model to develop in vitro root caries for investigating microbial modulation strategies. The model involved growing complex biofilms from a saliva inoculum collected from four volunteers using two strategies. In the first strategy (“pre-treatment strategy”), bovine root slabs were used, and two natural compounds were incorporated at time 0 of the 10-day biofilm experiment, which included sucrose cycles mimicking the cariogenic environment. In the second strategy (“post-treatment strategy”), mature biofilms were grown in a modified Calgary biofilm device coated with collagen and hydroxyapatite for 7 days and then were exposed to the same natural compounds. The metatranscriptome of each biofilm was then determined and analysed. Collagenase activity was examined, and the biofilms and dentine were imaged using confocal and scanning electron microscopy (SEM). Mineral loss and lesion formation were confirmed through micro-computed tomography (μ-CT).ResultsThe pH confirmed the cariogenic condition. In the metatranscriptome, we achieved a biofilm compositional complexity, showing a great diversity of the metabolically active microbiome in both pre- and post-treatment strategies, including reads mapped to microorganisms other than bacteria, such as archaea and viruses. Carbohydrate esterases had increased expression in the post-treated biofilms and in samples without sugar cycles, while glucosyltransferases were highly expressed in the presence of sucrose cycles. Enrichment for functions related to nitrogen compound metabolism and organic cyclic component metabolism in groups without sucrose compared to the sucrose-treated group. Pre-treatment of the roots with cranberry reduced microbial viability and gelatinase (but not collagenase) activity (p < 0.05). SEM images showed the complexity of biofilms was maintained, with a thick extracellular polysaccharides layer.ConclusionsThis root caries model was optimized to produce complex cariogenic biofilms and root caries-like lesions, and could be used to test microbial modulation in vitro. Pre-treatments before biofilm development and cariogenic challenges were more effective than post-treatments. The clinical significance lies in the potential to apply the findings to develop varnish products for post-professional tooth prophylaxis, aiming at implementing a strategy for dysbiosis reversal in translational research.2cRgxuoMbmgt6TZPkgExXQVideo

Sustainability in the winemaking industry and the assessment of grape seed characteristics during processing: Evidence from Azerbaijan

In the context of Azerbaijan’s evolving winemaking landscape, this study investigates the sustainability of viticulture with a particular focus on grape seeds, which are crucial for grapevine propagation, oil extraction, and overall vineyard health. The research aimed to examine the morphological, technological, and biochemical characteristics of grape seeds to optimise grape production methods and promote sustainable viticultural practices. To achieve this, seed samples from twelve grape varieties, both local and introduced, were carefully collected and analysed under varying irrigation conditions, including both irrigated and rainfed settings, to allow for a comprehensive assessment. The investigation revealed significant effects of irrigation on seed properties. Specifically, seeds from irrigated grapes were found to be larger, heavier, and richer in oil content compared to those from rainfed grapes. Detailed analyses showed that the nitrogen content of the seeds ranged from 0.96% to 1.46%, cellulose content varied from 18.8% to 25.3%, ash content ranged from 1.9% to 3.1%, nitrogenous compounds fluctuated between 5.5% and 7.2%, and non-nitrogen extractive substances registered between 16.6% and 22.0%. Notably, correlations between seed properties and the efficiency of cold press oil extraction were identified, providing valuable insights. This research ultimately contributes to the advancement of sustainable viticulture practices in Azerbaijan, ensuring the long-term health and productivity of vineyards within the region

Transformation of organic compounds of carbon and nitrogen of agrochernozems in the conditions of transition to waste-free processing technologies in the Krasnoyarsk forest-steppe

The influence of dump and non-dump tillage techniques on the transformation of mobile organic compounds of carbon and nitrogen in the conditions of the forest-steppe zone of theKrasnoyarskTerritory has been studied.The influence of the ratio of the content of easily mineralized carbon and nitrogen on this process is estimated.The value of theC:Nratio in the soil of the studied variants indicated an average level of nitrogen enrichment of humus.TheC:Nvalues for mobile forms of carbon and nitrogen had a broader relationship in the soil treated with the use of waste-free technologies.Strong correlations were found betweenC0.1NaOHand theC:Nratio in the soil.Under the conditions of application of dump processing technology, an increase in the provision of soil with active organic matter made it possible to stimulate the nitrogen mineralizing ability with the accumulation of ammonium nitrogen compounds.When using non-waste treatments, similar dependencies were found with the content of nitrate nitrogen compounds.The values ofСmbinСorg(%) indicated a weak biogenicity of the studied soil.There was no differentiation between the layers in terms of the rate of carbon dioxide emission.

The characteristic structural and functional dynamics of P. falciparum DHFR binding with pyrimidine chemotypes implicate malaria therapy design

Dihydrofolate reductase (DHFR) enzyme regulates de-novo folate synthesis in Plasmodium falciparum, hence a critical malaria drug target. Pyrimethamine inhibits DHFR, but resistance and lack of cross-species activity are key challenges. Therefore, this study is set to investigate more potent nitrogenous heterocyclic compounds against DHFR. Docking and MD simulations were employed to gain insight into the compounds’ binding free energies and conformational stabilities, while cross-species activity was determined using sequence alignment. Among the 500 screened compounds, PMD_01 (−12.2 kcal/mol), PMD_02 (−11.1 kcal/mol), PMD_03 (−10.7 kcal/mol), and PMD_04 (−10.7 kcal/mol) have the highest binding affinities against pfDHFR compared to pyrimethamine (−7.9 kcal/mol). Critical amino acids for binding interactions in the active site of pfDHFR include Leu45, Thr107, Ile164, and Thr170. PMD-bound systems showed higher binding free energy than pyrimethamine, except PMD_03. Hydrogen bonding interactions with Gly159, Ser101, Ser104, Ser160, Ile157, and Lys48 played significant roles in the binding interaction of these compounds as opposed to Asp53 in pyrimethamine. The four systems converged around 1.90 Å RMSD and showed more stability than pyrimethamine-bound and unbound pfDHFR. The pocket's residues across the four plasmodia were highly conserved, but Phe116 and Ile164 replaced Met in P. knowlesi and Tyr in the other species. PMD_01, PMD_02, PMD_03, and PMD_04 showed promising inhibition against pfDHFR and are, thus, potential antimalarial agents against plasmodia DHFR homologues.

Calculation of the formation enthalpies of charge-transfer complexes with iodine from the binding constants at 298.15 K

There is a continuing interest in charge-transfer complex chemistry, particularly in their formation thermodynamics. Nowadays, the binding constants and Gibbs energies of formation are available for many complexes. However, the experimental determination of the complexation enthalpies is a more difficult procedure, as it usually requires the establishment of the temperature dependence of the binding constant. Our recent studies of the compensation relationship in the thermodynamics of solvation in hydrogen-bonded systems opened the way to the calculation of the enthalpies of specific (i.e., localized donor-acceptor) interactions (Δint(sp)H) directly from the Gibbs energies at 298.15 K (Δint(sp)G). The calculation procedure is based on the following equation: Δint(sp)G/(kJ·mol−1) = 0.66·Δint(sp)H/(kJ·mol−1) + 2.5n (n corresponds to the coordination number of a solute).In the present work, we checked whether the above relation can be applied to the complex formation between halogens (primarily iodine) and organic electron donors. For 152 complexes with aromatics, nitrogen, oxygen, sulfur, selenium, and phosphor-containing compounds, the formation enthalpies were estimated using the data on equilibrium constants at 298.15 K. In most cases, agreement with the experimental binding enthalpies within the expected measurement error was observed (RMS = 1.4 kJ·mol−1, AD = –0.4 kJ·mol−1).

Co-pyrolysis of wheat straw with polyester-based polyurethane for nitrogenous compounds: Pyrolysis kinetic properties and synergistic effects

To re-utilize agricultural waste straw and waste plastic, the co-pyrolysis process of wheat straw (WS) and high-nitrogen polymer polyester-based polyurethane (PU) and the synergistic effects were studied. The results showed that PU facilitated pyrolysis to occur at lower temperatures. The effective apparent activation energies (Eα) of different samples were calculated at different conversion rates with three methods (Kissinger, KAS and Starink). It was found that PU decreased the Eα values and enthalpy change of WS and increased the reactivity. Both ΔG and ΔS results indicate that a heating rate of 5 ℃/min is more favorable for co-pyrolysis. PU greatly promoted the production of pyrolysis oil. Co-pyrolysis oil doped with 75 % PU gave the highest yield of 77 wt%. Co-pyrolysis effectively suppressed the production of acids, aldehydes, and phenols in pyrolysis oils. It increased the levels of alcohols and ketones, improving the pyrolysis oil's stability and calorific value. α, β-unsaturated aldehydes produced by WS during pyrolysis reacted with hydrazine derivatives produced by PU pyrolysis to produce pyrazole compounds after dehydration. In the co-pyrolysis of 50 % doped PU, the reaction of methyl and methylene produced by WS with amines (-NH2) produced by the pyrolysis of PU promotes the production of trimethylamine. The yield of amines in the nitrogenous compounds reached a maximum at this time. PU increased the yield of nitrogenous compounds and their variety. It favored the output of high-value chemicals. FT-IR analyses of pyrolytic charcoal showed that the addition of PU promoted the cleavage of WS and the dehydration and decarboxylation reactions of C-O and C-O-C. Finally, synergistic effects and nitrogen conversion mechanisms in the co-pyrolysis process are proposed. This work provided a theoretical basis for the resource utilization of WS waste and PU waste.

Visualization of metabolite distribution based on matrix-assisted laser desorption/ionization-mass spectrometry imaging of tea seedlings (Camellia sinensis).

Tea seedlings (Camellia sinensis) have a well-developed root system with a strong taproot and lateral roots. Compared with ordinary cuttings, tea has stronger vitality and environmental adaptability, thus facilitating the promotion of good varieties. However, there is less of detailed research on the rooting and germination process of tea seeds. In this study, matrix-assisted laser desorption ionization time-of-flight-mass spectrometry was used to conduct non-targeted spatial mass spectrometry imaging of the main organs during growth of tea seedlings. A total of 1234 compounds were identified, which could be divided into 24 classes. Among them, theanine, as the most prominent nitrogen compound, was synthesized rapidly at the early stage of embryo germination, accounting for >90% of the total free amino acids in the radicle, and it was then transferred to each meristem region through the mesocolumnar sheath, indicating that theanine-based nitrogen flow plays a decisive role in organ formation during the development of tea seedlings. Nutrients stored in the cotyledon were rapidly hydrolyzed to dextrin and 3-phosphoglyceraldehyde at the early stages of germination, and subsequently converted to other forms that provided carbon and energy for development, such as raffinose and d-galactose (glucose), which were mainly distributed in the growing zones of the root apex and the apical meristems of the stem. This study provides a new perspective on the synthesis and metabolism of substances during the development of tea seedlings and contributes to a better understanding of the biological characteristics of tea varieties.

Heterocyclic Nitrogen Compounds as Potential PDE4B Inhibitors in Activated Macrophages

Cyclic-nucleotide phosphodiesterases (PDEs) represent a superfamily of enzymes playing a pivotal role in cell signaling by controlling cAMP and cGMP levels in response to receptor activation. PDE activity and expression are linked to many diseases including inflammatory diseases. In light of their specific biochemical properties, PDE inhibition has attracted the interest of several researrs In this context, PDE4 inhibition induces anti-inflammatory effects. Piclamilast and rolipram, well-known PDE4 inhibitors, are endowed with common side effects. The selective phosphodiesterase 4B (PDE4B) inhibitors could be a promising approach to overcome these side effects. In the present study, six potential PDE4B inhibitors have been investigated. Through this study, we identified three PDE4B inhibitors in human macrophages activated by lipopolysaccharide. Interestingly, two of them reduced reactive oxygen species production in pro-inflammatory macrophages.