Organic Nitrogen Compounds Research Articles

An UPLC-Q-TOF/MS-Based Analysis of the Differential Composition of Dendrobium officinale in Different Regions.

Dendrobium officinale (D. officinale) is a valuable traditional Chinese herbal medicine with high commercial value. In Chinese Pharmacopoeia (Ch.P., 2020 edition), the quality of D. officinale is mainly evaluated by its polysaccharide content. However, varying growth and production conditions, such as cultivation environment, origin, harvesting process, or processing methods, resulting in highly variable yields, quality, and composition. The aim of this study was to investigate whether the content of secondary metabolites in D. officinale from different origins is consistent with the polysaccharide content. The results showed that the polysaccharide content and pass rate were ranked as GX > AH > GZ > YN. Based on the nontargeted metabolomics approach, we searched for differential components in 22 different regions of D. officinale, including amides, bibenzyls, disaccharide, flavonoids, organic nitrogenous compounds, and phenolic glycosides. The overall expression was opposite to the polysaccharide, and the most expressed was YN, followed by GZ, AH, and GX. These results indicated that the current quality standard for evaluating the quality of D. officinale by polysaccharide content alone is imperfect, and small molecule compounds need to be included as quality markers.

Assessing the Fate of Dissolved Organic Compounds in Landfill Leachate and Wastewater Treatment Systems.

Landfill leachate and municipal wastewater are major sources of chemical pollutants that contaminate our drinking water sources. Evaluating the dissolved organic chemical composition in wastewater treatment plants is therefore essential to understand how the discharge impacts the environment, wildlife, and human health. In this study, we utilized a nontargeted analysis method coupling liquid chromatography and tandem mass spectrometry (LC-MS/MS) to analyze chemical features at different points along two landfill leachate treatment plants (LLTPs) and two municipal wastewater treatment plants (WWTPs) in the Southeastern United States. Significant feature differences were observed for the WWTPs where activated sludge clarification was employed versus the LLTPs utilizing reverse osmosis. Specifically, even though both LLTPs had the largest number of features in their influent water, their effluent following reverse osmosis yielded a lower number of features than the WWTPs. Additionally, the clarification processes of each WWTP exhibited different efficiencies as chemical disinfection removed more features than UV disinfection. Feature identification was then made using the LC, MS, and MS/MS information. Analysis of the identified molecules showed that lipids were the most effectively removed from all plants, while alkaloid and organic nitrogen compounds were the most recalcitrant.

Radiation-induced transformation of the C2H2⋯NH3 complex in cryogenic media: Identification of C2H2⋯NH2∙ complex and evidence of cold synthetic routes

Acetylene and ammonia are important constituents of the interstellar medium, and their coupled chemistry induced by high-energy radiation may be responsible for the formation of a variety of prebiotically important organic-nitrogen compounds. In this work, we first comprehensively characterized the vibrational spectrum of the 1:1 C2H2⋯NH3 complex obtained by deposition of the C2H2/NH3/Ng (Ng = Ar, Kr, or Xe) gaseous mixtures at 5K using Fourier transform infrared spectroscopy and ab initio calculations at the CCSD(T)/L2a_3 level of theory and examined its radiation-induced transformations. The parent complex adopts a C3v symmetric top molecular structure with C2H2 acting as a proton donor. The x-ray-induced transformations of this complex result in the formation of the C2H2⋯NH2 ∙ complex and various CN-containing species (CH2CNH, CH3NC, CH2NCH, CH2NC∙, CCN∙, and CNC∙). The radical-molecule complex was identified based on comparison of experimental data with the results of the UCCSD(T)/L2a_3 computations. It is characterized by distinct features in the region of acetylene CHasym str mode, red-shifted from the corresponding absorptions of non-complexed acetylene by -72.9, -70.4, and -60.6cm-1 for Ar, Kr, and Xe, respectively. Additionally, in krypton and xenon matrices, the blue-shifted features in the CHasym bend region of acetylene were observed, which can be also tentatively attributed to the C2H2⋯NH2 ∙ complex. The extrapolated to the complete basis set limit unrestricted coupled cluster method with single and double, and perturbative triple excitations binding energy of the C2H2⋯NH2 ∙ complex (including zero-point vibration energy correction) is lower than that of the C2H2⋯NH3 complex (1.90 and 2.51kcal mol-1, respectively). We believe that the C2H2⋯NH2 ∙ complex may be an important intermediate in cold synthetic astrochemistry.

Metabolism Reorganization in Kale (Brassica oleracea L. var acephala) Populations with Divergent Glucosinolate Content under Thermal Stresses

Thermal stress causes the reduction in productivity and harvest quality. To adapt to different temperature ranges, plants activate protecting metabolic pathways. Previous studies have reported that stressful environments due to abiotic stresses have an impact on the accumulation of glucosinolates (GSLs) in Brassicaceae plants. In order to determine the role of GSLs in the plant response to thermal stress, we conducted a study comparing four populations with a high and low GSL content. The GSL levels were analysed at different temperatures [control (20), 12 and 32 °C], detecting that populations with a higher GSL content increased their resistance to the cold. In addition, populations subjected to the cold increased the content of indolic GSLs. Populations with high levels of GSLs show higher levels of glucobrassicin (GBS) and sinigrin (SIN) under cold temperatures than plants grown under control conditions. High temperatures have a lower impact on GSLs accumulation. To elucidate the induced metabolic changes due to the accumulation of GSLs under cold conditions, we performed an untargeted metabolomic analysis and identified 25 compounds differentially expressed under cold conditions in the populations with a high GSL content. Almost 50% of these compounds are classified as lipids (fatty amides, monoradylglycerols, diterpenes, glycosylglycerols, linoleic acids and derivatives). Organoheterocyclic and nitrogenous organic compounds are also over-represented. Therefore, the current results suggest that GSLs play a key role in cold tolerance. Although the associated molecular mechanisms have not been elucidated, the non-targeted metabolomics assay shows a significant change in the lipid profile, with compounds that need to be studied further.

Complete genome sequencing and analysis revealed the nitrogen utilization strategy of a novel Acuticoccus species isolated from surface water of the Indian Ocean.

Acuticoccus sp. I52.16.1 was isolated from 100m water depth from the Indian Ocean, and presented a novel Acuticoccus species belonging to the family Acuticoccaceae, class Alphaproteobacteria. The strain I52.16.1 displayed the activities of nitrate reductase, nitrite reductase, and urease. The genome of Acuticoccus sp. I52.16.1 consisted of a circular chromosome (5, 134, 086bp) with a G+C content of 69.7mol%. The predicted number of coding genes was 4935, including 6 rRNA, 47 tRNA, and 2 sRNA. The 16S rDNA sequence displayed the maximum similarity of 97.58% with Acuticoccus yangtzensis JL1095T, followed by Acuticoccus sediminis PTG4-2T (97.05%), Acuticoccus kandeliae J103T (96.52%), and Acuticoccus mangrove B2012T (95.85%). Acuticoccus sp. I52.16.1 contained clades of genes involved in assimilating ammonium, nitrate, nitrite, and simple organic nitrogen compounds, but lacked the pathway for dissimilatory denitrification. Two distinct types of ureases were also detected, suggesting genetic heterogeneity. This study provided insight into the nitrogen metabolism strategies of heterotrophic bacteria in the oligotrophic ocean surface.

Atmospheric oxidation mechanism and kinetics of indole initiated by ●OH and ●Cl: a computational study

Abstract. The atmospheric chemistry of organic nitrogen compounds (ONCs) is of great importance for understanding the formation of carcinogenic nitrosamines, and ONC oxidation products might influence atmospheric aerosol particle formation and growth. Indole is a polyfunctional heterocyclic secondary amine with a global emission quantity almost equivalent to that of trimethylamine, the amine with the highest atmospheric emission. However, the atmospheric chemistry of indole remains unclear. Herein, the reactions of indole with ⚫OH and ⚫Cl, and subsequent reactions of resulting indole radicals with O2 under 200 ppt NO and 50 ppt HO2⚫ conditions, were investigated by a combination of quantum chemical calculations and kinetics modeling. The results indicate that ⚫OH addition is the dominant pathway for the reaction of ⚫OH with indole. However, both ⚫Cl addition and H abstraction are feasible for the corresponding reaction with ⚫Cl. All favorably formed indole radicals further react with O2 to produce peroxy radicals, which mainly react with NO and HO2⚫ to form organonitrates, alkoxy radicals and hydroperoxide products. Therefore, the oxidation mechanism of indole is distinct from that of previously reported amines, which primarily form highly oxidized multifunctional compounds, imines or carcinogenic nitrosamines. In addition, the peroxy radicals from the ⚫OH reaction can form N-(2-formylphenyl)formamide (C8H7NO2), for the first time providing evidence for the chemical identity of the C8H7NO2 mass peak observed in the ⚫OH + indole experiments. More importantly, this study is the first to demonstrate that despite forming radicals by abstracting an H atom at the N site, carcinogenic nitrosamines were not produced in the indole oxidation reaction.

Simultaneous detection and quantification of different biogenic amines

Biogenic amines are a group of low molecular weight nitrogenous organic compounds that have an important physiological role in cell proliferation, differentiation, and signal transduction. Also, certain biogenic amines act as an important biomarker for the detection of neuroendocrine and cardiovascular disorders in humans. Besides this, the abundance of biogenic amines in food is recognized as a toxin and anti-nutritional element that have several health implications. This visual experiment demonstrates all the critical steps required for the extraction of biogenic amines followed by derivatization and high performance liquid chromatography analysis for the successive detection and quantification of biogenic amines such as histamine, cadaverine, tryptamine, agmatine, putrescine, 2-phenylethylamine, spermine, tyramine, and spermidine.

Chemical characterization of the water-soluble organic nitrogen in the maritime aerosol

In order to clarify the compound composition of the water-soluble organic nitrogen (WSON) in aerosols, simultaneous measurements of the WSON, free amino acids (FAA), combined amino acids (CAA), amines, and urea in the total suspended particles (TSP) were conducted at a remote coastal site located in the northern tip of Japan. About 15% of the water-soluble total nitrogen (WSTN) in the TSP was explained by the WSON, which suggests a significant contribution of the WSON to the bioavailable nitrogen in the TSP. About 22% of the WSON in the TSP can be explained by the FAA and CAA. Especially, the CAA showed about a 3.4-times higher concentration than the FAA and contributed about 17% of the WSON. The CAA would be a major compound group for the WSON in the TSP. The contribution of urea to the WSON was significant as a single compound; about 5% of the WSON in the TSP was explained by urea. In contrast, the contribution of amines to the WSON in the TSP was low. These four compound groups contributed about 29% of the WSON in the TSP. The contribution of the organic nitrogen compounds other than these four species to the WSON increased as the concentration of the WSON increased, which suggests that the high concentrations of the WSON in the TSP were significantly affected by the organic nitrogen compounds other than amino acids, amines, and urea.

Metabolomic Analysis of Wheat Grains after Tilletia laevis Kühn Infection by Using Ultrahigh-Performance Liquid Chromatography-Q-Exactive Mass Spectrometry.

Tilletia laevis causes common bunt disease in wheat, with severe losses of production yield and seed quality. Metabolomics studies provide detailed information about the biochemical changes at the cell and tissue level of the plants. Ultrahigh-performance liquid chromatography–Q-exactive mass spectrometry (UPLC-QE-MS) was used to examine the changes in wheat grains after T. laevis infection. PCA analysis suggested that T. laevis-infected and non-infected samples were scattered separately during the interaction. In total, 224 organic acids and their derivatives, 170 organoheterocyclic compounds, 128 lipids and lipid-like molecules, 85 organic nitrogen compounds, 64 benzenoids, 31 phenylpropanoids and polyketides, 21 nucleosides, nucleotides, their analogues, and 10 alkaloids and derivatives were altered in hyphal-infected grains. According to The Kyoto Encyclopedia of Genes and genomes analysis, the protein digestion and absorption, biosynthesis of amino acids, arginine and proline metabolism, vitamin digestion and absorption, and glycine, serine, and threonine metabolism pathways were activated in wheat crops after T. laevis infection.

Foliar application of potassium silicate, potassium fulvate and betaine improve summer-time tomato yield by promoting plant nitrogen and potassium uptake

Abstract During the summer months, greenhouse tomato production is challenged by the heat, causing yield reduction; therefore, we conducted a study to test the effectiveness of different foliar spray compositions for the improvement of Lycopersicon esculentum var. cerasiforme ‘Qianxi’ nutrition uptake and fruit yield. Two forms of silicon, two kinds of organic nitrogenous compounds and water as the control factor were two-two paired to become nine different recipes, which were as follows: CK (H2O), ISi (K2SiO3), organic silicon (OSi), potassium fulvate (BSFA), BSFA + ISi, BSFA + OSi, betaine (GB), GB + ISi and GB + OSi. The plants were sprayed three times during the period of the first, second and third truss fruit expansions with a 2-week interval. As a result, BSFA or K2SiO3 generated higher yield in plants compared with the other compositions. Also, K2SiO3 significantly enhanced the total nitrogen, phosphorus and potassium accumulation in fruit and the whole plant. Comparing across the nine recipes, BSFA + ISi, ISi and GB had improved the fruit yield by 17%, 12.7% and 9.5%, performing the best. BSFA + ISi, ISi and GB also improved the plant nitrogen uptake by 8.2%, 18.8% and 9.8%, as well as the potassium uptake by 16.2%, 12.3% and 15.2%, compared with CK, respectively. Thus, K2SiO3, BSFA and GB stimulated the plant nitrogen and potassium uptake, which improved the marketable yield.

Determination of Organic Nitrogen Compounds in Gasoline by Water-Assisted Dispersive Solid-Phase Extraction (DSPE) and High-Performance Liquid Chromatography-High-Resolution Mass Spectrometry (HPLC-HRMS)

For the identification of trace-level organic nitrogen compounds (NCs) in gasoline, a method consisting of water-assisted dispersive solid-phase extraction (DSPE) and high-performance liquid chromatography-high resolution mass spectrometry was developed in which mixed-mode cation exchange was used as the adsorbent. To increase the DSPE efficiency, water was dispersed into the gasoline to increase the pronation of NCs and enhance the ionic interaction with the adsorbent. After systematic optimization of DSPE conditions, including the adsorbent mass, sample volume, water to gasoline ratio, sample loading time, washing and elution solvents, sensitive determination of NCs (detection limits from 0.1 to 5 ng/L for the 14 analytes) was achieved by this method with a 100-fold enrichment. A number of unknown NC isomers were observed from the extracted ion chromatograms based on the accurate determination of mass-to-charge ratio (m/z), from which two sets of isomers at theoretical m/z of 122.09643 and 136.11208 were selected for identification. By careful elucidation of the product ion spectra of the selected ions, 16 NCs were putatively identified, in which six non-aniline homologs were reported for the first time.

Application of Biofloc Technology in Indonesian Eel Anguilla bicolor bicolor Fish Culture: Water Quality Profile

Nowadays biofloc technology which utilizes organic matter decomposition activity of heterotrophic bacteria through C/N ratio setting has been widely applied in aquaculture but has never been applied in eel farming. Water quality is a crucial factor in eel aquaculture, one of the prestigious fish commodities. Therefore, this study was conducted to determine the feasibility of biofloc technology to be applied in eel fish culture. The study was conducted using two different pond systems, i.e with and without a water recirculation system. Air in both systems was injected into the water to reach 7-8 mg/L of dissolved oxygen. Molasses and activated charcoal as a carbon source were added so as to achieve a C/N ratio of 20:1. Water quality and microbiology parameters were monitored weekly. The results showed that both biofloc systems were able to maintain water quality very well up to the eleventh week without water replacement, which was characterized by low content of total organic nitrogen and toxic compounds nitrite. Therefore the biofloc technology is suitable to be applied in eel aquaculture.

Combined radical and ionic approach for the enantioselective synthesis of β-functionalized amines from alcohols.

Chiral amines are among the most important organic compounds and have widespread applications. Enantioselective construction of chiral amines is a major aim in organic synthesis. Among synthetic methods, direct functionalization of omnipresent C-H bonds with common organic nitrogen compounds represents one of the most attractive strategies. However, C-H amination strategies are largely limited to constructing a specific type of N-heterocycles or amine derivatives. To maximize the synthetic potential of asymmetric C-H amination, we report here an approach that unites the complementary reactivities of radical and ionic chemistry for streamlined synthesis of functionalized chiral amines. This synthesis merges the development of an enantioselective radical process for 1,5-C(sp 3)-H amination of alkoxysulfonyl azides via Co(II)-based metalloradical catalysis with an enantiospecific ionic process for ring-opening of the resulting five-membered chiral sulfamidates by nucleophiles. Given that alkoxysulfonyl azides are derived from the corresponding alcohols, this approach offers a powerful synthetic tool for enantioselective β-C-H amination of common alcohols while converting the hydroxy group to other functionalities through formal nucleophilic substitution.

Enhanced boron modified graphitic carbon nitride for the selective photocatalytic production of benzaldehyde

Graphitic carbon nitride is a non-metal photocatalyst easily prepared from nitrogen organic compounds through green synthesis processes that do not require the use of solvents. This work proposes the use of boron to modify the layered g-C3N4 structure by incorporating B to induce defects aimed at the enhancement of the photocatalytic activity. Boron-modified graphitic carbon has been obtained using elemental B and NaBH4 as precursors. The XRD and FTIR characterization results suggest that the C and N positions of g-C3N4 can be replaced by B, resulting in a layered modified structure in which the tri-s-triazine units are altered. The exchange of B atoms differed from the boron precursor according to the analysis of the chemical properties of the surface. Thus, the elemental B had a preference to exchange positions with N atoms, whereas the use of NaBH4 led to the substitution of B into the C positions. This difference considerably affected the photocatalytic activity during the selective oxidation of benzyl alcohol. The sample modified with NaBH4 led to the highest oxidation rate and selectivity linked to a lesser recombination effect than the other samples according to photoluminescence tests. This work provides evidence about the convenience of the selection of precursors during the modification of g-C3N4. The photon absorbance rate was determined for the estimation of the quantum yield. Although the photon absorbance rate was quite similar in all the cases, the different registered kinetics led to a maximum quantum efficiency of 0.15% for NaBCN.

Advanced Research on Polymer Floating Carrier Application in Activated Sludge Reactors.

This research estimates the efficiency of domestic wastewater treatment in the removal of organic pollutants and nitrogen compounds with a two-stage treatment sequence (an activated sludge reactor in the first stage, and a trickling filter in the second stage), and with the application of floating carriers in the activated sludge reactor. The materials “Polyvom”, “Polystyrene” and “Bioballs” were adopted as floating carriers with previously determined filling ratios in the reactor volume of 10%, 20% and 20%, respectively. After the first stage of the study, it was found that the most effective treatment was achieved using the “Polyvom” material. Therefore, only this floating carrier was considered in the second and third stages of the study. Within the stages of the research, lab-scale benches operated under different operation modes of the treatment sequence. At the end of the study, it was possible to achieve the following levels of purification: BOD5 (2.1 mg/L), NH4 (0.4 mg/L), NO2 (1.0 mg/L), and NO3 (25 mg/L). The mean values of the concentrations of BOD, NH4, and NO3 met the requirements, but the concentration of NO2 exceeded the requirements (1.0 mg/L vs. 0.08 mg/L). These results were achieved under a hydraulic retention time in the activated sludge reactor of 8 h, and the MLSS for the free-floating and immobilized activated sludge was 0.2 and 0.9 g/L, respectively.

Metabolomic profiling of Dezhou donkey seminal plasma related to freezability

Donkeys are indispensable livestock in China because they have transport function and medicinal value. With the popularization of artificial insemination on donkeys, semen cryopreservation technology has gradually become a research hotspot. Seminal plasma is a necessary medium for transporting sperm and provides energy and nutrition for sperm. Seminal plasma metabolites play an important role in the process of sperm freezing, and also have an important impact on sperm motility and fertilization rate after freezing and thawing. In this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used to compare the metabolic characteristics of seminal plasma of high freezability (HF) and low freezability (LF) male donkeys. We identified 672 metabolites from donkey seminal plasma, of which 33 metabolites were significantly different between the two groups. Metabolites were identified and categorized according to their major chemical classes, including homogeneous non-metal compounds, nucleosides, nucleotides, and analogues, organosulphur compounds, phenylpropanoids and polyketide, organoheterocyclic compounds, organic oxygen compounds, benzenoids, organic acids and derivatives, lipids and lipid-like molecules, organooxygen compounds, alkaloids and derivatives, organic nitrogen compounds. The results showed that the contents of phosphatidylcholine, piceatannol and enkephalin in donkey semen of HF group were significantly higher than those of LF group (p < .05), while the contents of taurocholic and lysophosphatidic acid were significantly lower than those of LF group (p < .05). The different metabolites were mainly related to sperm biological pathway response and oxidative stress. These metabolites may be considered as candidate biomarkers for different fertility in jacks.

Probiotic additions affect the biofloc nursery culture of white shrimp (Litopenaeus vannamei)

In a biofloc technology (BFT) system, the bacterial community is crucial for organic matter metabolism and toxic nitrogenous compound recycling. This study evaluated the effects of the addition of either of two commercial probiotics (P1 and P2) on the biofloc condition, water quality, and growth and survival of white shrimp ( Litopenaeus vannamei ) in indoor BFT systems; indoor BFT systems without the addition of any probiotic was used as the control. The culture density was 150 juvenile shrimp (weight, 0.06 ± 0.01 g) in 200-L tanks with a culture period of 40 days. The salinity of the culture water was 15 ppt, and molasses was added to the tank for maintaining a C/N ratio of 15. In the P1, P2, and control groups, the floc volume was 3.7 ± 0.5, 3.5 ± 0.6, and 3.0 ± 0.6 mL/L, respectively, and the total heterotrophic bacterium densities were (5.8 ± 1.4) × 10 6 , (4.5 ± 1.5) × 10 6 , and (3.6 ± 1.1) × 10 6 colony forming unit (CFU)/mL, respectively; these values were significantly higher in the treatment groups than in the control group (all P < 0.05). The major groups in the biofloc comprised zooplankton community were provided by rotifers, copepods, nematodes , and protists . The addition of probiotics increased nitrite‑nitrogen and nitrate‑nitrogen levels in the culture water of P1 (7.7 ± 1.0 and 5.9 ± 0.5 ppm, respectively) and P2 (8.4 ± 0.7 and 6.2 ± 0.6 ppm, respectively) groups; they were significantly higher in the treatment groups than in the control group (6.1 ± 0.8 and 5.0 ± 0.8 ppm, respectively). L. vannamei growth rates were significantly higher in the P1 group than in the P2 and control groups. However, the between-group differences in the survival rates were not significant. In conclusion, the addition of probiotics to the BFT system with L. vannamei effectively enhanced the water quality, floc volume, and total bacterial number in the water and the growth performance of the shrimp. • Both probiotics resulted in higher floc volumes and total heterotrophic bacteria. • Both probiotics increased NIN and NAN in water. • P1 increased growth performance (weight gain and FCR); P2 and control did not. • Vibrio harveyi challenge provided no significant differences among treatments.

Integrated analysis of changes in soil microbiota and metabolites following long-term fertilization in a subtropical maize-wheat agroecosystem

Although the application of inorganic fertilizer is a widespread agronomic practice used to boost soil productivity and crop yields, the effects on soil microbiome and the metabolic mechanisms involved in the high-yield response of crops to long-term fertilization remain poorly described. In this study, combined metagenomic and metabolomic analyses were used to explore the mechanism of crop yield response to the 20-year application of nitrogen-phosphorus-potassium fertilizers in a subtropical agroecosystem in Southwest China. Soil bacterial and fungal communities were monitored using 16S rRNA (bacteria) and internal transcribed spacer 1 (ITS1) full-length gene (fungi) amplicon sequencing technologies, and metabolites were detected using a liquid chromatograph mass spectrometer. The results revealed that, in addition to providing nutrients, long-term fertilization shaped the compositions of bacteria and fungi to increase crop yields. Long-term fertilization significantly increased the relative abundances of plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi and promoted the secretion of soil metabolites such as carbohydrates, organic acids, and organic nitrogen compounds, which were primarily enriched in amino acid metabolism pathways. The increases in carbon and nitrogen sources and bioactive substances in soil promoted the increases in plant biomass and thereby maintained soil quality and production capacity. The findings highlighted the importance of soil metabolites in maintaining soil productivity as well as crop yields, and suggested that regulating key metabolites could increase crop yields in agroecosystems.

Simultaneous recovery of nutrients and improving the biodegradability of waste algae hydrothermal liquid

The ever-increasing algae biomass due to eutrophication brings an enormous destruction and potential threat to the ecosystem. Hydrothermal carbonization (HTC) is a potential means converting algae to value added products such as sustainable bioenergy and biomaterials. However, the waste aqueous phase (AP) produced during the HTC of algae biomass needs to be treated carefully in case of the second pollution to environment. In this study, a model microbe (E. coli) was adopted for the microbial pretreatment of AP, by which the bioavailability of AP could be improved, and the nutrients could be reclaimed though struvite precipitation. Three-dimensional fluorescence spectra and GC-MS results illustrated that E. coli pretreatment could convert a large number of organic nitrogenous compounds to ammonia nitrogen by degrading aromatic protein substances and deaminating nitrogenous heterocyclic compounds. Afterwards, a serious of characterizations confirmed that 81.13% of ammonia nitrogen could be recovered as struvite though precipitation. Life cycle assessment indicates the cost of the two-step treatment process was much lower than that of conventional wastewater treatment processes, and is beneficial to environment. This work provides an environment-friendly strategy for the comprehensive utilization of algae, which may contribute to alleviating the algal disasters and bring certain economic benefits though algal treatment.

HARMFUL EFFECTS OF HISTAMINE IN THE BODY: A REVIEW

Histamine is a bioactive nitrogenous organic compound of the family of monoamines produced by the action of enzymes in human and animal dung by fecal bacteria on protein materials, particularly the essential amino acid histidine. This type of material is also secreted in abundance in the body by cells known as mast cells circulating in the connective tissues, and also by white blood cells known as basophils, basal white blood cells, during allergic reactions and serious and life-threatening anaphylactic shock called anaphylactic shock (and during various allergic diseases). Mast cells are abundantly present in lung tissue, nasal mucosa, eye mucosal tissue, subcutaneous and between various mucosal tissues. In addition to what was mentioned above about the characteristics and functional role of histamine in the body, it has many harms as a result of its high level secretion as a result of a specific functional disorder or microbial invasion, as well as as a result of immune sensitivity, and damages are noted in the respiratory, digestive, immune and nervous systems.