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1.
Environ Monit Assess ; 194(6): 399, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35499665

RESUMO

Ephemeral river systems in Nigeria are under severe threat by increasing anthropogenic pollution. However, little is known about the ecological health of ephemeral rivers in Afrotropical regions, especially Nigeria. It is also unclear how zooplankton communities respond to anthropogenic stressors in ephemeral rivers in the African continent. In this study, we explored the responses of zooplankton to environmental indicators of human activities to assess the health of River Kafin Hausa, an ephemeral river system in north-western Nigeria. Our specific objectives were to explore the response patterns of zooplankton communities to anthropogenic pollution in the north-western ephemeral rivers and examine their potential use as reliable indicators for long-term monitoring of ephemeral systems impacted by different human activities. We collected zooplankton and physicochemical variables from three sites in five months, from January to February and April to June 2018. One-way ANOVA showed air temperature, water temperature, pH, salinity, BOD5, phosphate and nitrate varied significantly (p < 0.05) between the sites across the 5 months. We recorded four zooplankton groups, namely Cladocera, Copepoda, Protozoa and Rotifera. The cluster analysis revealed that the organisms were grouped mainly by sites rather than by seasons. The multivariate canonical correspondence analysis (CCA) revealed a weak association between the zooplankton community assemblages and physicochemical variables. However, there were differential responses of zooplankton to physicochemical variables in the river system, with species such as Eurytemora affinis, Acartia tonse and Sinodiaptomus sarsi being sensitive, indicating positive associations with DO concentration. Conversely, species such as Macrothrix rosea and Bosmina longirostris were tolerant, demonstrating their usefulness as bioindicators of bad water quality as they associated positively with TDS, water depth, nitrates and salinity. Overall, the study revealed further insights into the responses of zooplankton communities to pollution, and their potential use as indicators organisms in ephemeral rivers.


Assuntos
Cladóceros , Copépodes , Animais , Monitoramento Ambiental , Atividades Humanas , Humanos , Nitratos , Rios/química , Qualidade da Água , Zooplâncton
2.
Commun Biol ; 5(1): 432, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35534536

RESUMO

Nitrate is a nutrient signal that regulates growth and development through NLP transcription factors in plants. Here we identify the L-aspartate oxidase gene (AO) necessary for de novo NAD+ biosynthesis as an NLP target in Arabidopsis. We investigated the physiological significance of nitrate-induced AO expression by expressing AO under the control of the mutant AO promoter lacking the NLP-binding site in the ao mutant. Despite morphological changes and severe reductions in fresh weight, the loss of nitrate-induced AO expression resulted in minimum effects on NAD(H) and NADP(H) contents, suggesting compensation of decreased de novo NAD+ biosynthesis by reducing the growth rate. Furthermore, metabolite profiling and transcriptome analysis revealed that the loss of nitrate-induced AO expression causes pronounced impacts on contents of TCA cycle- and urea cycle-related metabolites, gene expression profile, and their modifications in response to changes in the nitrogen nutrient condition. These results suggest that proper maintenance of metabolic balance requires the coordinated regulation of multiple metabolic pathways by NLP-mediated nitrate signaling in plants.


Assuntos
Arabidopsis , Arabidopsis/metabolismo , Ácido Aspártico/metabolismo , Expressão Gênica , Regulação da Expressão Gênica de Plantas , NAD/metabolismo , Nitratos/metabolismo , Nitrogênio/metabolismo , Nutrientes
3.
Mikrochim Acta ; 189(5): 206, 2022 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-35501613

RESUMO

Concerns for agri-food safety and environmental management require development of simple to use and cost- and time-effective multiplex sensors for point-of-need (PON) chemical analytics by public end-user. Simultaneous detection of nitrates, phosphates, and pH is of importance in soil and water analysis, agriculture, and food quality assessment. This article demonstrates a suite of stainless steel microneedle electrochemical sensors for multiplexed measurement of pH, nitrate, and phosphate using faradaic capacitance derived from cyclic voltammetry as the mode of detection. The multi-target microneedle sensors were fabricated by layer-by-layer (LbL) assembly in a stainless steel hypodermic microneedle substrate. For nitrate sensing, the stainless steel was coated with carbon nanotube/cellulose nanocrystal (CNT)/CNC) decorated with silver nanoparticles (Ag). For pH measurement, the polyaniline (pANI) was coated onto the CNT/CNC@Ag film, while for phosphate detection, the CNT/CNC/Ag @pANI microneedle was further decorated with ammonium molybdenum tetrahydrate (AMT). The microelectrode platforms were characterized by FTIR, Raman, and microscopic techniques. The nitrate- and phosphate-based microneedle electrochemical sensors had excellent selectivity and sensitivity, with a determined limit of detection (LOD) of 0.008 mM and 0.007 mM, respectively. The pH microneedle sensor was responsive to pH in the linear range of 3-10. The three microneedle sensors yielded repeatable results, with a precision ranging from 4.0 to 7.5% RSD over the concentration ranges tested. The inexpensive (~ 1 $ CAD) microneedle sensors were successfully verified for use in quantification of nitrate, pH, and phosphate in brewed black coffee as a real sample. As such, the microneedle sensors are economical devices and show great promise as robust platforms for PON precision chemical analytics.


Assuntos
Nanopartículas Metálicas , Nitratos , Celulose , Técnicas Eletroquímicas/métodos , Concentração de Íons de Hidrogênio , Fosfatos , Prata/química , Aço Inoxidável
4.
Water Res ; 216: 118381, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35381430

RESUMO

Dark carbon fixation (DCF) contributes approximately 0.77 Pg C y-1 to oceanic primary production and the global carbon budget. It is estimated that nearly half of the DCF in marine sediments occurs in estuarine and coastal regions, but the environmental factors controlling DCF and the microorganisms responsible for its production remain under exploration. In this study, we investigated DCF rates and the active chemoautotrophic microorganisms in intertidal sediments of the Yangtze Estuary, using 14C-labeling and DNA-stable isotope probing (DNA-SIP) techniques. The measured DCF rates ranged from 0.27 to 3.37 mmol C m-2 day-1 in intertidal surface sediments. The rates of DCF were closely related to sediment sulfide content, demonstrating that the availability of reductive substrates may be the dominant factor controlling DCF in the intertidal sediments. A significant positive correlation was also observed between the DCF rates and abundance of the cbbM gene. DNA-stable isotope probing (DNA-SIP) results further confirmed that cbbM-harboring bacteria, rather than cbbL-harboring bacteria, played a dominant role in DCF in intertidal sediments. Phylogenetic analysis showed that the predominant cbbM-harboring bacteria were affiliated with Burkholderia, including Sulfuricella denitrificans, Sulfuriferula, Acidihalobacter, Thiobacillus, and Sulfurivermis fontis. Moreover, metagenome analyses indicated that most of the potential dark-carbon-fixing bacteria detected in intertidal sediments also harbor genes for sulfur oxidation, denitrification, or dissimilatory nitrate reduction to ammonium (DNRA), indicating that these chemoautotrophic microorganisms may play important roles in coupled carbon, nitrogen, and sulfur cycles. These results shed light on the ecological importance and the underlying mechanisms of the DCF process driven by chemoautotrophic microorganisms in intertidal wetlands.


Assuntos
Bactérias , Ciclo do Carbono , Bactérias/genética , Carbono , DNA , Sedimentos Geológicos/química , Nitratos/análise , Nitrogênio , Filogenia , Enxofre
5.
Water Res ; 216: 118351, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35390703

RESUMO

Nitrate (NO3-) is a ubiquitous contaminant in water and wastewater. Conventional treatment processes such as adsorption and membrane separation suffer from low selectivity for NO3- removal, causing high energy consumption and adsorbents usage. In this study, we demonstrate selective removal of NO3- in an electrosorption process by a thin, porous carbonized eggshell membrane (CESM) derived from eggshell bio-waste. The CESM possesses an interconnected hierarchical pore structure with pore size ranging from a few nanometers to tens of micrometers. When utilized as the anode in an electrosorption process, the CESM exhibited strong selectivity for NO3- over Cl-, SO42-, and H2PO4-. Adsorption of NO3- by the CESM reached 2.4 × 10-3 mmol/m2, almost two orders of magnitude higher than that by activated carbon (AC). More importantly, the CESM achieved NO3-/Cl- selectivity of 7.79 at an applied voltage of 1.2 V, the highest NO3-/Cl- selectivity reported to date. The high selectivity led to a five-fold reduction in energy consumption for NO3- removal compared to electrosorption using conventional AC electrodes. Density function theory calculation suggests that the high NO3- selectivity of CESM is attributed to its rich nitrogen-containing functional groups, which possess higher binding energy with NO3- compared to Cl-, SO42-, and H2PO4-. These results suggest that nitrogen-rich biomaterials are good precursors for NO3- selective electrodes; similar chemistry can also be used in other materials to achieve NO3- selectivity.


Assuntos
Nitratos , Purificação da Água , Animais , Carvão Vegetal , Casca de Ovo , Eletrodos , Nitratos/química , Nitrogênio , Óxidos de Nitrogênio , Porosidade , Águas Residuárias , Água , Purificação da Água/métodos
6.
Water Res ; 216: 118292, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35421667

RESUMO

If we can use toxic aromatic compounds as supplementary carbon source, the simultaneous removal of nitrate (NO3-) and aromatic compounds may be achieved at much lower chemical costs. This study uses the expanded granular sludge bed (EGSB) reactors to investigate the hypersaline (> 3%) denitrification performance, the removal of aromatic compounds, i.e., aniline, phenol, and their mixture, and the mechanisms involved in. The four reactors exhibit high removal efficiency of NO3- (> 92.8%) and aromatic compounds (> 73.9%) at 0-1200 mg/L of aromatic compounds. The formation of toxic intermediates such as catechol and azo dyes is revealed by gas chromatography mass spectrometry (GC-MS) with and without N,O-Bis(trimethylsilyl) trifluoroacetamide (BSTFA) derivation, and their toxic effects lead to the lower cell survival ratios after exposing to phenol (64.2% ∼ 68.9%) than to aniline and mixture (72.7% ∼ 78.0%). The stable performance is associated with the more secretion of extracellular polymeric substances (EPS) and the adsorption of pollutants on EPS, and this was indicated from the higher fluorescence intensity in three-dimensional excitation-emission matrix (3D-EEM). Moreover, the Halomonas and Azoarcus show high abundance and play important roles in the removal of both NO3- and aromatic compounds. Besides, quantitative real time PCR (RT-qPCR) results demonstrate the key role of highly abundant nosZ and nirS genes in denitrification. The toxic organics in industrial wastewaters are potentially feasible carbon sources for denitrification even under high-salinity stress.


Assuntos
Desnitrificação , Poluentes Ambientais , Reatores Biológicos , Carbono , Nitratos , Nitrogênio , Óxidos de Nitrogênio , Compostos Orgânicos , Fenol , Esgotos
7.
Environ Monit Assess ; 194(5): 376, 2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35437732

RESUMO

Monitoring in remote areas can represent a real challenge in environmental studies. Numerous techniques have been developed over the last decades to monitor nutrients and other elements in different systems. However, not all of them are suitable for field applications, particularly when the locations are difficult to access or its accessibility depends on seasonal climate conditions. This study was aimed to test the applicability and efficiency of resin samplers and resin bags to monitor nitrates fluxes (NO3-N) in two small semi-arid catchments in Northwestern Mexico. Resin samplers were installed in the hyporheic zone below the river bed in order to monitor the vertical fluxes of NO3-N and remained there for 5 months (during the summer rains). Resin bags were anchored in rock outcrops upstream of the resin samplers before the onset of the summer rainfall season and replaced every 2 weeks during 4 months to capture pulses of NO3-N in ephemeral streams. NO3-N pulses in the stream are a potential source of NO3-N that can infiltrate into the soil. Results of the resin samplers found a difference of up to 12 kg ha-1 season-1 between the two catchments. The resin bags showed a higher accumulation of NO3-N in the catchment with lower vegetation cover (160.3 mg L-1 season-1) compared to the one with higher vegetation (67.8 mg L-1 season-1). Measured nitrate fluxes at both sites responded to rainfall pulses recorded during the monitoring period. Resin samplers and resin bags can be used together, to assess nutrient fluxes on the surface and in the soil and can be tested in any type of ecosystem. In this particular case, these methods demonstrated an efficient way of determining spatio-temporal nitrate fluxes in semi-arid ecosystems in remote areas that are difficult to access, monitor, and collect data.


Assuntos
Nitratos , Rios , Ecossistema , Monitoramento Ambiental , Resinas de Troca Iônica , Nitratos/análise , Nitrogênio/análise , Óxidos de Nitrogênio , Solo
8.
Cell Commun Signal ; 20(1): 47, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35392923

RESUMO

BACKGROUND: NOS2 expression is mostly found in bacteria-exposed or cytokine-treated tissues and is mostly connected to innate immune reactions. There are three isoforms of NOS2 (NOS2-1 to -3). In RNA-seq data sets, analyzing inflammatory gene expression, only expression of the NOS2-1 mRNA isoform is detected. However, the expression of NOS2 in differentiating human pluripotent stems (hPSCs) has not been analyzed yet. METHODS: Public available RNA-seq databases were screened for data of hPSCs during differentiation to different target cells. An isoform specific algorithm was used to analyze NOS2 mRNA isoform expression. In addition, we differentiated four different human iPSC cell lines toward cortical neurons and analyzed NOS2 mRNA expression by qRT-PCR and 5'-RACE. The functionality of the NOS2-2 protein was analyzed by transient transfection of expression clones in human DLD1 cells and nitrate measurement in the supernatant of these cells. RESULTS: In RNA-seq databases we detected a transient expression of the NOS2 mRNA during the differentiation of hPSCs to cardiomyocytes, chondrocytes, mesenchymal stromal cells, neurons, syncytiotrophoblast cells, and trophoblasts. NOS2 mRNA isoform specific analyses showed, that the transiently expressed NOS2 mRNA in differentiating hPSC (NOS2-2; "diff-iNOS") differ remarkably from the already described NOS2 transcript found in colon or induced islets (NOS2-1; "immuno-iNOS"). Also, analysis of the NOS2 mRNA- and protein expression during the differentiation of four different hiPSC lines towards cortical neurons showed a transient expression of the NOS2 mRNA and NOS2 protein on day 18 of the differentiation course. 5'-RACE experiments and isoform specific qRT-PCR analyses revealed that only the NOS2-2 mRNA isoform was expressed in these experiments. To analyze the functionality of the NOS2-2 protein, we transfected human DLD-1 cells with tetracycline inducible expression clones encoding the NOS2-1- or -2 coding sequence. After induction of the NOS2-1 or -2 mRNA expression by tetracycline a similar nitrate production was measured proofing the functionality of the NOS2-2 protein isoform. CONCLUSIONS: Our data show that a differentiation specific NOS2 isoform (NOS2-2) is transiently expressed during differentiation of hPSC. Video Abstract.


Assuntos
Células-Tronco Pluripotentes , Isoformas de RNA , Tetraciclina , Diferenciação Celular , Humanos , Isoenzimas/genética , Nitratos/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Células-Tronco Pluripotentes/citologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
9.
Nitric Oxide ; 122-123: 54-61, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35405336

RESUMO

Nitric oxide (NO) is complex modulator of skeletal muscle contractile function, capable of increasing or decreasing force and power output depending on multiple factors. This review explores the effects and potential mechanisms for modulation of skeletal muscle contractile function by NO, from pharmacological agents in isolated muscle preparations to dietary nitrate supplementation in humans and animals. Pharmacological manipulation in vitro suggests that NO signaling diminishes submaximal isometric force, whereas dietary manipulation in vivo suggest that NO enhances submaximal force. The bases for these different responses are unknown but could reflect dose-dependent effects. Maximal isometric force is unaffected by physiologically relevant levels of NO, which do not induce overt protein oxidation. Pharmacological and dietary manipulation of NO signaling enhances the maximal rate of isometric force development, unloaded shortening velocity, and peak power. We hypothesize that these effects are mediated by post-translational modifications of myofibrillar proteins that modulate thick filament regulation of contraction (e.g., mechanosensing and strain-dependence of cross-bridge kinetics). NO effects on contractile function appear to have some level of fiber type and sex-specificity. The mechanisms behind NO-mediated changes in skeletal muscle function need to be explored through proteomics analysis and advanced biophysical assays to advance the development of small molecules and open intriguing therapeutic and ergogenic possibilities for aging, disease, and athletic performance.


Assuntos
Contração Muscular , Óxido Nítrico , Animais , Contração Muscular/fisiologia , Músculo Esquelético/metabolismo , Nitratos/metabolismo , Óxido Nítrico/metabolismo , Sarcômeros
10.
PLoS One ; 17(4): e0266057, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35427386

RESUMO

This study primarily focused on how to effectively remove nitrate by catalytic denitrification through zero-valent iron (Fe0) and Pd-Ag catalyst. Response surface methodology (RSM), instead of the single factor experiments and orthogonal tests, was firstly applied to optimize the condition parameters of the catalytic process. Results indicated that RSM is accurate and feasible for the condition optimization of catalytic denitrification. Better catalytic performance (71.6% N2 Selectivity) was obtained under the following conditions: 5.1 pH, 127 min reaction time, 3.2 mass ration (Pd: Ag), and 4.2 g/L Fe0, which was higher than the previous study designed by single factor experiments and orthogonal tests, 68.1% and 68.7% of N2 Selectivity, respectively. However, under this optimal conditions, N2 selectivity showed a mild decrease (69.3%), when the real wastewater was used as influent. Further study revealed that cations (K+, Na+, Ca2+, Mg2+, and Al3+) and anions (Cl-, HCO3-, and SO42-) exist in wastewater could have distinctive influence on N2 selectivity. Finally, the reaction mechanism and kinetic model of catalytic denitrification were further studied.


Assuntos
Desnitrificação , Ferro , Catálise , Nitratos , Águas Residuárias
11.
Arch Iran Med ; 25(2): 105-111, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35429947

RESUMO

BACKGROUND: Coronary artery disease is among the first causes of death in Iran. Secondary prevention with drug therapy is recommended following acute myocardial infarction (MI) to reduce the risk of new cardiovascular events and death. METHODS: This is a retrospective cohort study on data collected from 21181 cases of MI recorded by the MI Registry of Iran from 2013 to 2014. Ten therapies that were prescribed to patients at the time of discharge were divided into 6 groups. Survival rates were estimated using the Kaplan-Meier method and Cox regression analysis. RESULTS: The most common MI location was in the anterior wall (31.87%). Anticoagulants, aspirin, clopidogrel were the most common prescribed medications (94.73%). Overall, 28-day (short-term) and 3-year survival rates were 0.95 (95% CI: 0.95-0.96) and 0.82 (95% CI: 0.81-0.82). In non-ST-elevation myocardial infarction (NSTEMI) patients, the lowest short- and long-term survival rates were observed when diuretic, anticoagulants/ aspirin and clopidogrel, beta-blockers and statins medication were simultaneously taken and the highest short- and long-term survival rates were observed in patients who took anticoagulants, aspirin and clopidogrel, nitrate agent and calcium blockers, beta-blockers and statins medication. In STEMI patients, the lowest short- and long-term survival rates were observed when diuretic, anticoagulants, aspirin and clopidogrel, nitrate agent and calcium blockers, angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) were simultaneously taken. The highest short- and long-term survival rates were observed in patients who received anticoagulants, aspirin and clopidogrel, nitrate agent and calcium blockers, beta-blockers, statins, ACEIs and ARBs. CONCLUSION: Prescription of the best combination of drugs, in addition to adherence to a healthy lifestyle and medication, can improve the survival rates after MI.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases , Infarto do Miocárdio , Antagonistas Adrenérgicos beta/uso terapêutico , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Anticoagulantes/uso terapêutico , Aspirina/uso terapêutico , Cálcio , Clopidogrel/uso terapêutico , Diuréticos/uso terapêutico , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Irã (Geográfico)/epidemiologia , Infarto do Miocárdio/tratamento farmacológico , Nitratos/uso terapêutico , Alta do Paciente , Sistema de Registros , Estudos Retrospectivos , Taxa de Sobrevida
12.
Environ Monit Assess ; 194(5): 326, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35381908

RESUMO

This study investigated, for the first time, the role of cerium oxide nanoparticles (CeO2 NPs) on dairy effluent nitrate and phosphate bioremediation using different inoculum sources. Two inoculum sources (wastewater and sludge) were obtained from the dairy wastewater treatment plant unit. A culture was prepared to be tested in the treatment of nitrate and phosphate effluent, and the role of CeO2 NPs was checked to be completely efficient after 5 days of incubation. The reduction efficiency of nitrate using sludge as inoculum source was improved up to 89.01% and 68.12% for phosphate compared to control. In the case of using wastewater as an inoculum source, the nitrate reduction was improved up to 83.30% and 87.75% for phosphate compared to control. The bacterial richness showed a significant variance (higher richness) between control and other samples. The optimal concentration of CeO2 NPs for inoculum richness and nitrate and phosphate reduction was (sludge: 1 × 10-10 ppm) and (wastewater: 1 × 10-12 ppm). The results revealed that CeO2 NPs could enhance the microbial growth of different inoculum sources that have a key role in dairy effluent nitrate and phosphate bioremediation.


Assuntos
Cério , Nanopartículas Metálicas , Nanopartículas , Biodegradação Ambiental , Cério/análise , Monitoramento Ambiental , Nitratos , Fosfatos
13.
J Environ Sci (China) ; 114: 354-364, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35459498

RESUMO

To investigate particle characteristics and find an effective measure to control severe particle pollution, year-round observation of size-segregated inorganic aerosols was conducted in Beijing from January to December, 2016. The sampled atmospheric particles all presented bimodal size distribution at four pollution levels (clear, slight pollution, moderate pollution and severe pollution), and peak values appeared at the size range of 0.7-2.1 µm and >9.0 µm, respectively. As dominant particle compositions, NO3-, SO42-, and NH4+ in four pollution levels all showed significant peaks in fine mode, especially at the size range of 1.1-2.1 µm. Secondary inorganic aerosols accounted for about 67.6% (36.3% (secondary sulfates) + 31.3% (secondary nitrates)) of the total sources of fine particles in urban Beijing. Severe pollution of fine particles was mainly caused by the air masses transported from nearby western and southern areas, which are industrial and densely populated region, respectively. Sensitivity tests further revealed that the control measures focusing on ammonium emission reduction was the most effective for particle pollution mitigation, and fine particles all showed nonlinear responses after reducing ammonium, nitrate, and sulfate concentrations, with the fitting curves of y = -120.8x - 306.1x2 + 290.2x3, y = -43.5x - 67.8x2, and y = -25.8x - 110.4x2 + 7.6x3, respectively (y and x present fine particle mass variation (µg/m3) and concentration reduction ratio (CRR)/100 (dimensionless)). Overall, our study presents useful information for understanding the characteristics of atmospheric inorganic aerosols in urban Beijing, as well as offers policy makers with effective measure for mitigating particle pollution.


Assuntos
Poluentes Atmosféricos , Compostos de Amônio , Aerossóis/análise , Poluentes Atmosféricos/análise , Compostos de Amônio/análise , Pequim , China , Monitoramento Ambiental , Nitratos/análise , Tamanho da Partícula , Material Particulado/análise , Estações do Ano , Sulfatos/análise
14.
J Environ Sci (China) ; 114: 376-390, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35459501

RESUMO

Comprehensive observations of the nocturnal atmospheric oxidation of NO3 and N2O5 were conducted at a suburban site in Changzhou in the YRD using cavity ring-down spectroscopy (CRDS) from 27 May to 24 June, 2019. High concentrations of NO3 precursors were observed, and the nocturnal production rate of NO3 was determined to be 1.7 ± 1.2 ppbv/hr. However, the nighttime NO3 and N2O5 concentrations were relatively low, with maximum values of 17.7 and 304.7 pptv, respectively, illustrating the rapid loss of NO3 and N2O5. It was found that NO3 dominated the nighttime atmospheric oxidation, accounting for 50.7%, while O3 and OH only contributed 34.1% and 15.2%, respectively. For the reactions of NO3 with volatile organic compounds (VOCs), styrene was found to account for 60.3%, highlighting its dominant role in the NO3 reactivity. In general, the contributions of the reactions between NO3 and VOCs and the N2O5 uptake to NO3 loss were found to be about 39.5% and 60.5%, respectively, indicating that N2O5 uptake also played an important role in the loss of NO3 and N2O5, especially under the high humidity conditions in China. The formation of nitrate at night mainly originated from N2O5 uptake, and the maximum production rate of NO3- reached 6.5 ppbv/hr. The average NOx consumption rate via NO3 and N2O5 chemistry was found to be 0.4 ppbv/h, accounting for 47.9% of the total NOx removal. The predominant roles of NO3 and N2O5 in nitrate formation and NOx removal in the YRD region was highlighted in this study.


Assuntos
Nitratos , Rios , China , Monitoramento Ambiental , Nitratos/análise , Óxidos de Nitrogênio/química
15.
J Environ Sci (China) ; 114: 503-513, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35459512

RESUMO

Air pollution in China is complex, and the formation mechanism of chemical components in particulate matter is still unclear. This study selected three consecutive heavy haze pollution episodes (HPEs) during winter in Beijing for continuous field observation, including an episode with heavy air pollution under red alert. Clean days during the observation period were selected for comparison. The HPE characteristics of Beijing in winter were: under the influence of adverse meteorological conditions such as high relative humidity, temperature inversion and low wind speed; and strengthening of secondary transformation reactions, which further intensified the accumulation of secondary aerosols and other pollutants, promoting the explosive growth of PM2.5. PM2.5/CO values, as indicators of the contribution of secondary transformation in PM2.5, were approximately 2 times higher in the HPEs than the average PM2.5/CO during the clean period. The secondary inorganic aerosols (sulfate nitrate and ammonium salt) were significantly enhanced during the HPEs, and the conversion coefficients were remarkably improved. In addition, it is interesting to observe that the production of sulfate tended to exceed that of nitrate in the late stage of all three HPEs. The existence of aqueous phase reactions led to the explosive growth sulfur oxidation ratio (SOR) and rapid generation of sulfate under high relative humidity (RH>70%).


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Pequim , China , Monitoramento Ambiental , Nitratos/análise , Óxidos de Nitrogênio/análise , Material Particulado/análise , Estações do Ano , Sulfatos/análise
16.
Exp Gerontol ; 163: 111798, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35390489

RESUMO

Hypertrophy in white adipose tissue (WAT) can result in sustained systemic inflammation, hyperlipidaemia, insulin resistance, and onset of senescence in adipocytes. Inflammation and hypertrophy can be induced in vitro using palmitic acid (PA). WAT adipocytes have innately low ß-oxidation capacity, while inorganic nitrate can promote a beiging phenotype, with promotion of ß-oxidation when cells are exposed to nitrate during differentiation. We hypothesized that treatment of human adipocytes with PA in vitro can induce senescence, which might be attenuated by nitrate treatment through stimulation of ß-oxidation to remove accumulated lipids. Differentiated subcutaneous and omental adipocytes were treated with PA and nitrate and senescence markers were analyzed. PA induced DNA damage and increased p16INK4a levels in both human subcutaneous and omental adipocytes in vitro. However, lipid accumulation and lipid droplet size increased after PA treatment only in subcutaneous adipocytes. Thus, hypertrophy and senescence seem not to be causally associated. Contrary to our expectations, subsequent treatment of PA-induced adipocytes with nitrate did not attenuate PA-induced lipid accumulation or senescence. Instead, we found a significantly beneficial effect of oleic acid (OA) on human subcutaneous adipocytes when applied together with PA, which reduced the DNA damage caused by PA treatment.


Assuntos
Nitratos , Ácido Oleico , Adipócitos , Dano ao DNA , Humanos , Hipertrofia , Inflamação , Nitratos/farmacologia , Ácido Oleico/farmacologia , Palmitatos/farmacologia
17.
Mar Pollut Bull ; 178: 113634, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35417808

RESUMO

The groundwater salinization is a global problem that degrades water quality and endangers sustainable use of water resources, particularly in coastal areas. In this paper, 24 water samples were collected from 12 monitoring wells during the dry (January) and wet (June) seasons for analyzing the salinization and hydrogeochemical characteristics of groundwater in Dongshan Island of China through combined hydrogeochemical and multivariate statistical approaches. Results showed that groundwater in the study area is primarily Cl-Na and followed by Cl-Ca·Mg type in the dry season, Cl-Na and followed by Cl-Ca·Mg and HOC3·Cl-Na type in the wet season. The groundwater chemistry is predominantly controlled by carbonate, gypsum, and silicate dissolution. However, some areas are strongly influenced by seawater intrusion, sewage infiltration and reverse ion exchange process. Around 40% of water samples from the dry season and 50% from the wet season are at injuriously, highly and severely saline levels while other samples at slightly and moderately saline levels, suggesting that groundwater in the area is partially recharged by seawater. Furthermore, the NO3-/Cl- versus Cl- diagram and principal component analysis (PCA) indicated nitrate pollution in groundwater that is subjected to anthropogenic activities such as domestic sewage, agricultural and industrial practices, which lead to degradation of groundwater quality in the area. The findings of this study provide helpful insights for understanding the genesis and hydrogeochemical evolution of groundwater in those coastal areas.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Monitoramento Ambiental/métodos , Água Subterrânea/análise , Nitratos/análise , Esgotos/análise , Poluentes Químicos da Água/análise
18.
Sci Rep ; 12(1): 6924, 2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35484294

RESUMO

To investigate the effects of extended light/dark (L/D) cycle period (relative to the diurnal L/D cycle) on lettuce and explore potential advantages of abnormal L/D cycles, butter leaf lettuce were grown in a plant factory with artificial light (PFAL) and exposed to mixed red (R) and blue (B) LED light with different L/D cycles that were respectively 16 h light/8 h dark (L16/D8, as control), L24/D12, L48/D24, L96/D48 and L120/D60. The results showed that, all the abnormal L/D cycles increased shoot dry weight (DW) of lettuce (by 34-83%) compared with the control, and lettuce DW increased with the L/D cycle period prolonged. The contents of soluble sugar and crude fiber in lettuce showed an overall upward trend with the length of L/D cycle extended, and the highest vitamin C content as well as low nitrate content were both detected in lettuce treated with L120/D60. The light use efficiency (LUE) and electric use efficiency (EUE) of lettuce reached the maximum (respectively 5.37% and 1.76%) under L120/D60 treatment and so were DW, Assimilation rate (A), RC/CS, ABS/CS, TRo/CS and DIo/CS, indicating that longer L/D cycle period was beneficial for the assimilation efficiency and dry matter accumulation in lettuce leaves. The highest shoot fresh weight (FW) and nitrate content detected in lettuce subjected to L24/D12 may be related to the vigorous growth of root, specific L/D cycle seemed to strengthen root growth and water absorption of lettuce. The openness level of RC in PSII (Ψo), ETo/CS, and PIabs were all the highest in lettuce treated with L24/D12, implying that slightly extending the L/D cycle period might promote the energy flowing to the final electron transfer chain. In general, irradiation modes with extended L/D cycle period had the potential to improve energy use efficiency and biomass of lettuce in PFAL. No obvious stress or injury was detected in lettuce subjected to prolonged L/D cycles in terms of plant growth and production. From the perspective of shoot FW, the optimal treatment in this study was L24/D12, while L120/D60 was the recommended treatment as regards of the energy use efficiency and nutritional quality.


Assuntos
Alface , Fotossíntese , Manteiga , Luz , Nitratos/análise , Fotossíntese/efeitos da radiação
19.
Microb Cell Fact ; 21(1): 73, 2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35484589

RESUMO

BACKGROUND: The construction of protein expression systems is mainly focused on carbon catabolite repression and quorum-sensing systems. However, each of these regulatory modes has an inherent flaw, which is difficult to overcome. Organisms also prioritize using different nitrogen sources, which is called nitrogen catabolite repression. To date, few gene regulatory systems based on nitrogen catabolite repression have been reported. RESULTS: In this study, we constructed a nitrogen switching auto-inducible expression system (NSAES) based on nitrogen catabolite regulation and nitrogen utilization in Aspergillus nidulans. The PniaD promoter that is highly induced by nitrate and inhibition by ammonia was used as the promoter. Glucuronidase was the reporter protein. Glucuronidase expression occurred after ammonium was consumed in an ammonium and nitrate compounding medium, achieving stage auto-switching for cell growth and gene expression. This system maintained a balance between cell growth and protein production to maximize stress products. Expressions of glycosylated and secretory proteins were successfully achieved using this auto-inducible system. CONCLUSIONS: We described an efficient auto-inducible protein expression system based on nitrogen catabolite regulation. The system could be useful for protein production in the laboratory and industrial applications. Simultaneously, NSAES provides a new auto-inducible expression regulation mode for other filamentous fungi.


Assuntos
Compostos de Amônio , Repressão Catabólica , Compostos de Amônio/metabolismo , Glucuronidase , Nitratos/metabolismo , Nitrogênio/metabolismo
20.
Zhonghua Yu Fang Yi Xue Za Zhi ; 56(4): 427-432, 2022 Apr 06.
Artigo em Chinês | MEDLINE | ID: mdl-35488538

RESUMO

Objective: To identify and analyze two strains of C. diphtheriae in Guangdong Province by combining whole genome sequencing with traditional detection methods. Methods: The C. diphtheriae was isolated from Guangzhou in 2010 and Zhuhai in 2020 respectively. Isolates were identified by API Coryne strips and MALDI-TOF-MS. Genomic DNA was sequenced by using Illumina. The assembly was performed for each strain using CLC software. J Species WS online tool was used for average nucleoside homology identification, then narKGHIJ and tox gene were detected by NCBI online analysis tool BLSATN. MEGA-X was used to build a wgSNP phylogenetic tree. Results: GD-Guangzhou-2010 was Belfanti and GD-Zuhai-2020 was Gravis. ANIb between GD-Guangzhou-2010 and C. belfantii was 99.61%. ANI between GD-Zhuhai-2020 and C. diphtheriae was 97.64%. BLASTN results showed that the nitrate reduction gene narKGHIJ and tox gene of GD-Guangzhou-2010 was negative, while GD-Zhuhai-2020 nitrate reduction gene narKGHIJ was positive. There were two obvious clades in wgSNP phylogenetic tree. The first clades included all Mitis and Gravis types strains as well as GD-Zhuhai-2020. The second clades contained all isolates of C.belfantii, C.diphtheriae subsp. lausannense and GD-guangzhou-2010. Conclusion: Two non-toxic C. diphtheriae strains are successfully isolated and identified. The phylogenetic tree suggests that GD-Guangzhou-2010 and GD-Zhuhai-2020 are located in two different evolutionary branches.


Assuntos
Corynebacterium diphtheriae , Difteria , China/epidemiologia , Corynebacterium , Corynebacterium diphtheriae/genética , Difteria/epidemiologia , Difteria/microbiologia , Humanos , Nitratos , Filogenia
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