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1.
Sci Total Environ ; 773: 145673, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33940756

RESUMO

Salinization can change the soil environment and affect microbial processes. In this study, soil samples were collected from Zone A (Phragmites australis wetlands), Zone B (P. australis and Suaeda salsa wetlands), and Zone C (Spartina alterniflora wetlands) in the Yellow River Delta. The microbial community and functional potential along the natural salinity gradient were investigated. Total nitrogen, ammonia nitrogen, and soil organic matter presented a downward trend, and salinity first increased and then decreased from Zone A to Zone C. Nitrospira and norank_f_Nitrosomonadaceae were widely distributed throughout the zones. Denitrifying bacteria Alcanivorax, Marinobacterter, and Marinobacterium were abundant in Zone B and preferred high salinity levels. However, denitrifying bacteria Azoarcus, Flavobacterium, and Pseudomonas were mainly distributed in low-salinity Zones A and C, suggesting their high sensitivity to salinity. Dissimilatory nitrate reduction to ammonia (DNRA) bacteria Aeromonas and Geobacter dominated Zone C, whereas Caldithrix performed DNRA in Zone B. Interestingly, DNRA with organic matter as the electron donor (C-DNRA) occurred in Zone A; DNRA coupled with sulfide oxidation (S-DNRA) was dominant in Zone B; and C-DNRA and DNRA with divalent iron as electron donor and S-DNRA occurred simultaneously in Zone C. Salinity was the key factor distinguishing low and high salinity zones, and total nitrogen and total phosphorus had important effects at the phylum and genus levels. The abundance of genes encoding cell growth and death was relatively stable, indicating that the microbial community had good environmental adaptability. The genes related to the biodegradation of xenobiotics and the metabolism of terpenoids and polyketides were abundant in Zone B, revealing high metabolic potential for exogenous refractory substances. The microorganisms under low-salinity Zones A and C were more sensitive to environmental changes than those under Zone B. These results suggest that salinity plays important roles in microbial processes and shapes specific functional zones in coastal wetlands.


Assuntos
Rios , Salinidade , Desnitrificação , Nitratos , Nitrogênio
2.
Environ Monit Assess ; 193(5): 303, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33900460

RESUMO

Examples of the utility of UV optical nitrate sensors are provided for two field applications, investigating nitrate pollution in a lowland, peri-urban catchment. In one application, rapid, in-stream longitudinal nitrate surveys were made in summer and winter, by fixing an optical nitrate sensor operating in continuous measurement mode to a kayak that was paddled along 10 km of the mainstem of the low-order stream in under 4 h. Nitrate concentrations ranged between 3.45 and 6.39 mg NO3-N/L. Nitrate hot-spots and cool-spots were mapped and found to relate to point discharges from spring-fed tributaries and land drains. Effective nitrate removal (dN/dx = - 0.08 mg N/L/km), inferred to be from assimilation reactions, was evident in the summer dataset, but not the winter nitrate dataset. In a second application, the optical sensor was configured with appropriate technology to establish an autonomous and fully automated nitrate monitoring station. The station makes daily nitrate measurements of surface water, and groundwater, sampled from a cluster of four multi-level wells. Quarterly maintenance of the nitrate sensor has proven sufficient to keep measurement errors under 5%. Most nitrate variation has been recorded at or near the water table where concentrations have ranged between 3.47 and 5.88 mg NO3-N/L, and annual maxima have occurred in late winter/spring, which coincides with when most nitrate leaching occurs from agricultural land. Seasonal nitrate patterns are not evident in groundwater sampled from 8-m depth, or deeper. High-frequency monitoring has revealed that some infra-season, short-term variability also occurs in shallow groundwater nitrate, driven by storm events, and which on occasion results in a temporary inversion of the groundwater nitrate-depth profile.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Agricultura , Monitoramento Ambiental , Nitratos/análise , Água , Poluentes Químicos da Água/análise
3.
Medicine (Baltimore) ; 100(15): e25417, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33847640

RESUMO

BACKGROUND: 68Ga-PSMA-PET/CT (positron emission tomography/computed tomography) is a promising method for prostate cancer (PC) detection. However, the ability of 68Ga-PSMA-PET/CT to detect malignant bone lesions, and whether this method is superior to the existing bone imaging methods are still lack of systematic analysis. PURPOSE: To evaluate the value of 68Ga-PSMA-PET/CT and bone scan in clinical diagnosis of prostatic cancer from the perspective of evidence-based medicine. METHODS: PubMed, The Cochrane Library, EMBASE, Springer Link, Sinomed, CNKI, Wanfang database, and CQVIP database were searched to find the satisfactory studies that needed systematic review of trials and compared the value of 68Ga-PSMA-PET/CT and bone scan. All studies published from inception to March 31, 2020. According to the inclusion and exclusion criteria, 2 reviewers independently evaluated and extracted the literature. Review Manager 5.3 was applied to evaluate the included literature quality. The heterogeneity of the included literature was tested by Meta Disc 1.4, and the effect model was selected according to the heterogeneity test results, and the sensitivity (SEN), specificity (SPE), PLR, NLR and diagnostic odds ratio (DOR) were analyzed. After testing the heterogeneity results of literature by using the 95% confidence interval and the forest map. RESULTS: A total of 4 studies were eligible for inclusion in the meta-analysis, which included 318 patients, 120 cases with bone metastasis and 198 cases without bone metastasis. The results of summary evaluation for 68Ga-PSMA-PET/CT and bone scan in diagnosis of prostatic cancer as follow respectively: The SEN were 0.97 and 0.86; the SPE were 1.00 and 0.87; the DOR were 1468.33 and 36.23; PLR were 88.45 and 6.67; NLR were 0.05 and 0.19; and the area under curve (AUC) and 95% CI were 0.9973 (1.0000-0.9927) and 0.8838 (0.9584-0.8092). CONCLUSION: By comparing the diagnostic results of 68Ga-PSMA-PET/CT and bone scan imaging diagnosis methods, the 68Ga-PSMA-PET/CT has a higher SEN and SPE than bone scan, and it has a higher diagnostic efficiency for prostate cancer bone metastasis, which is worthy of clinical application.


Assuntos
Neoplasias Ósseas/secundário , Ácido Edético/análogos & derivados , Oligopeptídeos/administração & dosagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Próstata/patologia , Compostos Radiofarmacêuticos/administração & dosagem , Tomografia Computadorizada por Raios X/métodos , Neoplasias Ósseas/diagnóstico por imagem , Combinação de Medicamentos , Ácido Edético/administração & dosagem , Fluoretos , Humanos , Masculino , Nitratos , Fosfatos , Neoplasias da Próstata/diagnóstico por imagem
4.
Environ Monit Assess ; 193(5): 297, 2021 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-33893885

RESUMO

A fast, efficient, and non-chromatographic method was presented in this study for nitrite, nitrate, and p-nitrophenol (N-compounds) extraction and speciation analysis of environmental samples. By applying ultrasound-assisted solid-liquid extraction (USLE), analytes were efficiently extracted from water, soil, or sediment collected in areas of environmental disaster. These analytes were selectively converted to NO(g) through UV photolysis (NO3-), H2O2/UV photocatalysis (PNP), and direct conversion (NO2-). Following conversion, NO(g) was separated from the liquid phase and determined by high-resolution continuum source molecular absorption spectrometry (HR-CS MAS). The LODs obtained were 0.097 ± 0.004 mg L-1 for nitrite, 0.119 ± 0.004 mg L-1 for nitrate, and 0.090 ± 0.006 mg L-1 for p-nitrophenol. On applying this speciation method to environmental samples, concentrations were found to be up to 0.99 ± 0.03 mg L-1 (NO2-), 49.80 ± 2.5 mg L-1 (NO3-), and 0.10 ± 0.02 mg L-1 (PNP). Finally, addition/recovery study of real water, soil, and sediment samples showed 101 ± 2% recovery for NO2-, 100 ± 1% for NO3-, and 96 ± 5% for PNP.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água , Peróxido de Hidrogênio , Nitratos/análise , Nitritos/análise , Extração em Fase Sólida , Poluentes Químicos da Água/análise
5.
Science ; 372(6539): 287-291, 2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33859034

RESUMO

Nutrient supply regulates the activity of phytoplankton, but the global biogeography of nutrient limitation and co-limitation is poorly understood. Prochlorococcus adapt to local environments by gene gains and losses, and we used genomic changes as an indicator of adaptation to nutrient stress. We collected metagenomes from all major ocean regions as part of the Global Ocean Ship-based Hydrographic Investigations Program (Bio-GO-SHIP) and quantified shifts in genes involved in nitrogen, phosphorus, and iron assimilation. We found regional transitions in stress type and severity as well as widespread co-stress. Prochlorococcus stress genes, bottle experiments, and Earth system model predictions were correlated. We propose that the biogeography of multinutrient stress is stoichiometrically linked by controls on nitrogen fixation. Our omics-based description of phytoplankton resource use provides a nuanced and highly resolved description of nutrient stress in the global ocean.


Assuntos
Genes Bacterianos , Metagenoma , Oceanos e Mares , Fitoplâncton/genética , Fitoplâncton/fisiologia , Prochlorococcus/genética , Prochlorococcus/fisiologia , Adaptação Fisiológica , Oceano Atlântico , Oceano Índico , Ferro/metabolismo , Metagenômica , Nitratos/metabolismo , Nitrogênio/metabolismo , Fixação de Nitrogênio/genética , Nutrientes , Oceano Pacífico , Fosfatos/metabolismo , Fósforo/metabolismo , Fitoplâncton/metabolismo , Prochlorococcus/metabolismo , Água do Mar/microbiologia , Estresse Fisiológico/genética
6.
Bioresour Technol ; 331: 125065, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33819908

RESUMO

The co-existence of nitrate, manganese (Mn), and antibiotics are of a wide concern. In this study, a denitrifying and manganese-oxidizing Zoogloea Q7 bacterium was immobilized using polyvinyl alcohol/sodium alginate with sponge cube (PVA/SA@sponge cube) in the reactor. The optimal operation parameters of the bioreactor were explored. Maximum nitrate, Mn(II), and tetracycline (TC) removal efficiencies of 93.00, 72.34, and 57.32% were achieved with HRT of 10 h, pH of 6.5, Mn(II) concentration of 20 mg L-1, and TC of 1 mg L-1, respectively. Fluorescence excitation-emission matrix (EEM) proved that the microorganism in the bioreactor was greatly active. Scanning electron microscope (SEM) images demonstrated that Zoogloea Q7 was commendably immobilized on the novel material. X-ray diffraction (XRD) analysis suggested that the bioprecipitate was mainly composed of MnO2 and MnCO3. Through high-throughput analysis, Zoogloea sp. Q7 was considered to be the dominant bacteria present in the bioreactor.


Assuntos
Nitratos , Álcool de Polivinil , Alginatos , Antibacterianos , Reatores Biológicos , Desnitrificação , Manganês , Compostos de Manganês , Óxidos
7.
Environ Sci Technol ; 55(9): 5782-5790, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33848129

RESUMO

Additional evidence indicates that the nitrate stored in the deep soil profile has an important role in regulating the global nitrogen (N) cycle. This study assessed the effects of land-use changes from croplands to intensive orchards (LUCO) on N surplus, nitrate accumulation in deep soil, and groundwater quality in the kiwifruit belt of the northern slope region of the Qinling Mountains, China. LUCO resulted in comparatively high N surplus in orchards (282 vs 1206 kg ha-1 yr-1, respectively). The average nitrate accumulation within the 0-10 m profiles of orchards was 7113 kg N ha-1, which was equal to approximately the total N surplus of 6 years of the orchards. The total nitrate stock within 0-10 m soil profiles of the kiwifruit belt was 266.5 Gg N, which was 3.5 times higher than the total annual N input. The nitrate concentrations of 97% of groundwater samples exceeded the WHO standard. The LUCO resulted in large nitrate storage in the vadose zone and caused serious contamination of groundwater. Our study highlights that nitrate accumulation in the vadose zone of an intensive land-use system is one of the main fates of surplus N and also a hotspot of nitrate accumulation.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Agricultura , China , Produtos Agrícolas , Nitratos/análise , Poluentes Químicos da Água/análise
8.
Environ Sci Technol ; 55(9): 5711-5720, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33861585

RESUMO

Particulate nitrate photolysis can produce oxidants (i.e., OH, NO2, and NO2-/HNO2) in aqueous droplets and may play a potential role in increased atmospheric oxidative capacity. Our earlier works have reported on the SO2 oxidation promoted by nitrate photolysis to produce sulfate. Here, we used glyoxal as a model precursor to examine the role of particulate nitrate photolysis in the formation of secondary organic aerosol (SOA) from particle-phase oxidation of glyoxal by OH radicals. Particles containing sodium nitrate and glyoxal were irradiated at 300 nm. Interestingly, typical oxidation products of oxalic acid, glyoxylic acid, and higher-molecular-weight products reported in the literature were not found in the photooxidation process of glyoxal during nitrate photolysis in the particle phase. Instead, formic acid/formate production was found as the main oxidation product. At glyoxal concentration higher than 3 M, we found that the formic acid/formate production rate increases significantly with increasing glyoxal concentration. Such results suggest that oxidation of glyoxal at high concentrations by OH radicals produced from nitrate photolysis in aqueous particles may not contribute significantly to SOA formation since formic acid is a volatile species. Furthermore, recent predictions of formic acid/formate concentration from the most advanced chemical models are lower than ambient observations at both the ground level and high altitude. The present study reveals a new insight into the production of formic acid/formate as well as a sink of glyoxal in the atmosphere, which may partially narrow the gap between model predictions and field measurements in both species.


Assuntos
Glioxal , Nitratos , Aerossóis , Formiatos , Fotólise
9.
Environ Sci Technol ; 55(8): 4410-4419, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33793220

RESUMO

Nitrated phenols (NPs) are important atmospheric pollutants that affect air quality, radiation, and health. The recent development of the time-of-flight chemical ionization mass spectrometer (ToF-CIMS) allows quantitative online measurements of NPs for a better understanding of their sources and environmental impacts. Herein, we deployed nitrate ions as reagent ions in the ToF-CIMS and quantified six classes of gaseous NPs in Beijing. The concentrations of NPs are in the range of 1 to 520 ng m-3. Nitrophenol (NPh) has the greatest mean concentration. Dinitrophenol (DNP) shows the greatest haze-to-clean concentration ratio, which may be associated with aqueous production. The high concentrations and distinct diurnal profiles of NPs indicate a strong secondary formation to overweigh losses, driven by high emissions of precursors, strong oxidative capacity, and high NOx levels. The budget analysis on the basis of our measurements and box-model calculations suggest a minor role of the photolysis of NPs (<1 ppb h-1) in producing OH radicals. NPs therefore cannot explain the underestimated OH production in urban environments. Discrepancies between these results and the laboratory measurements of the NP photolysis rates indicate the need for further studies aimed at understanding the production and losses of NPs in polluted urban environments.


Assuntos
Poluentes Atmosféricos , Nitratos , Poluentes Atmosféricos/análise , Pequim , Monitoramento Ambiental , Gases/análise , Fenóis/análise
10.
Artigo em Inglês | MEDLINE | ID: mdl-33799443

RESUMO

This case study covers the application of the fuzzy optimization in simultaneously satisfying various constraints that include the compliance of ammonia and nitrate concentrations with stringent environmental standards. Essential components in the multi-criteria decision-making analysis is in the utilization of the Box-Behnken design (BBD) response equations, cost equations and the cumulative uncertainty of response towards the sodium chloride dosage, current density and electrolysis time parameters. The energy consumption in the electrochemical oxidation of ammonia plays an essential role in influencing the total operating cost analysis. The determination of boundary limits based on the global optimum resulted in the complete ammonia removal and USD 64.0 operating cost as its maximum boundary limits and the 40.6% ammonia removal and USD 17.1 as its minimum boundary limits. Based on the fuzzy optimal results, the overall satisfaction level incurred a decrease in adhering with a lower ammonia standard concentration (10 mg/L at 80.3% vs. 1.9 mg/L at 76.1%) due to a higher energy consumption requirement. Global optimal fuzzy results showed to be highly cost efficient (232.5% lower) as compared to using BBD alone. This demonstrates the practicality of fuzzy optimization applications in the electrochemical reactions.


Assuntos
Amônia , Eletrólise , Eletrodos , Nitratos , Oxirredução
11.
Artigo em Inglês | MEDLINE | ID: mdl-33804377

RESUMO

Since 2005, over 30 epidemiological studies have evaluated the association between nitrate in drinking water and adverse health outcomes. Conditions that lead to nitrate pollution in water, such as open defecation, the proximity of septic tanks to water sources, and the use of inorganic fertilizer, are rampant in Indonesia, which has experienced little research evaluating nitrate in drinking water. We conducted a health risk assessment for exposure to nitrate in drinking water and evaluated the nitrate concentration in key water sources in two villages of rural Central Java, Indonesia. The nitrate concentrations in the drinking water ranged from 3.55 mg/L to 26.75 mg/L as NO3-. Daily nitrate intake estimates, calculated at 50% and 95% exposure to the maximum nitrate concentration of the drinking water in both villages, were above the levels associated with birth defects, colorectal cancer, and thyroid conditions observed in other studies. There was a large variation in nitrate concentrations between and within the villages at different water sources. Further research into whether these health outcomes exist in rural Central Java, Indonesia will be required to better understand this risk.


Assuntos
Água Potável , Poluentes Químicos da Água , Água Potável/análise , Humanos , Indonésia , Nitratos/análise , Nitratos/toxicidade , Óxidos de Nitrogênio , Medição de Risco , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Abastecimento de Água
12.
J Environ Manage ; 289: 112484, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33813296

RESUMO

In this study, the activation with ZnCl2 and heat treatment at 950 °C were performed to polyacrylonitrile-based carbon fiber and phenol resin to prepare two types of activated carbon fibers (ACFs) with different amounts of quaternary nitrogen (N-Q). In order to investigate the effect of chemical properties of ACFs on nitrate adsorption, various experiments and assess were conducted on these samples. The pHpzc of Py-7.0Z4-9.5HT10 and PhR-6.0Z4-9.5HT30 was about 7.1 and 7.0, respectively, and was no significant difference in the results. The C-π sites had a large effect on the amount of nitrate adsorption, and its adsorption capacity was greatest when the solution pH was about 3. However, the adsorption affinity (Ke) of C-π sites was weaker than that of N-Q, and the contribution for adsorption was small when the solution was low concentration or neutral, while the N-Q was the dominant adsorption site of ACFs. It is expected that the N-Q affected the adsorption kinetics, and the higher the amount of N-Q, the faster the adsorption rate. Py-7.0Z4-9.5HT10 had a large amount of C-π sites and N-Q. Therefore, the equilibrium adsorption amount (Qe) of Py-7.0Z4-9.5HT10 was 1.02 mmol/g at solution pH 3, and the adsorption kinetics were also fast.


Assuntos
Carvão Vegetal , Nitratos , Adsorção , Fibra de Carbono , Concentração de Íons de Hidrogênio , Cinética , Nitrogênio
13.
J Environ Manage ; 289: 112473, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33819654

RESUMO

Ibuprofen has caused great concerns due to their potential environmental risks. However, their removal efficiency and their effects on microbial interactions in bio-electrochemical system remain unclear. To address these issues, a lab-scale bio-electrochemical reactor integrated with sulfur/iron-mediated autotrophic denitrification (BER-S/IAD) system exposing to 1000 µg L-1 ibuprofen was operated for about two months. Results revealed that the BER-S/IAD system obtained efficient simultaneous denitrification (98.93%) and phosphorus (82.67%) removal, as well as an excellent ibuprofen removal performance (96.98%). Ibuprofen had no significant impacts on the nitrate (NO3--N) removal and the ammonia (NH4+-N) accumulation, but decreased the total nitrogen (TN) and total phosphorus (TP) removal efficiencies. MiSeq sequencing analysis revealed that ibuprofen significantly (P < 0.05) decreased the microbial community diversity and changed their overall structure. Some bacteria related to denitrification and phosphorus removal, such as Pseudomonas and Thiobacillus, decreased significantly (P < 0.05). Moreover, molecular ecological network (MEN) analysis revealed that ibuprofen decreased the network's size and complexity, and enhanced the negative correlations of Proteobacteria and Firmicutes. Besides, ibuprofen decreased the links of some keystone bacteria related to denitrification and phosphorus removal. This research could provide a new dimension for our comprehending of the responses of microbial communities and their interactions to ibuprofen in bio-electrochemical system.


Assuntos
Ibuprofeno , Microbiota , Reatores Biológicos , Desnitrificação , Humanos , Nitratos , Nitrogênio , Fósforo , Águas Residuárias
14.
J Environ Manage ; 289: 112521, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33839611

RESUMO

Woodchip bioreactors are widely known as a best management practice to reduce excess nitrate loads that are discharged with agricultural leachates. The aim of this study was to evaluate the performance of citrus woodchip bioreactors for denitrification of brine (electrical conductivity ≈ 17 mS cm-1) from groundwater desalination plants with high nitrate content (NO3--N ≈ 48 mg L-1) in the Campo de Cartagena agricultural watershed, one of the main providers of horticultural products in Europe. The performance was evaluated relative to seasonal changes in temperature, dissolved organic carbon (DOC) provided by woodchips, hydraulic residence time (HRT) and woodchip aging. Bioreactors (capacity 1 m3) operated for 2.5 years (121 weeks) in batch mode (24 h HRT) with three batches per week. Denitrification efficiency was modulated by DOC concentration, temperature, hydraulic residence time and the drying-rewetting cycles. High salinity of brine did not prevent nitrate removal from occurring. The high DOC availability (>25 mg C L-1) during the first ≈48 weeks resulted in high nitrate removal rate (>75%) and nitrate removal efficiency (until ≈ 25 g N m-3 d-1) regardless of temperature. Moreover, the high DOC contents in the effluents during this period may present environmental drawbacks. Denitrification was still high after 2.5 years (reaching ≈9.3 g N m-3 d-1 in week 121), but dependence on warm temperature became more apparent with woodchips aging from week ≈49 onwards. Nitrate removal efficiency was highest on the first weekly batch, immediately after woodchips had been unsaturated for four days. It was attributable to a flush of DOC produced by aerobic microbial metabolism during drying that stimulated denitrification following re-saturation. Hence, alternance of drying-rewetting cycles is an operation practice that increase bioreactors nitrate removal performance.


Assuntos
Desnitrificação , Água Subterrânea , Reatores Biológicos , Europa (Continente) , Nitratos , Sais
15.
Bioresour Technol ; 332: 125113, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33853027

RESUMO

In this study, fungal pellets immobilized denitrifying Pseudomonas stutzeri sp. GF3 was cultivated to establish a bioreactor. The denitrification effect of fixed bacteria with fungal pellets was tested by response surface methodology (RSM). Analysis of the bioreactor showed that the denitrification efficiency reached 100% under the optimal conditions and the denitrification efficiency of the actual wastewater treatment in the stable phase reached 95.91%. Moreover, the organic matter and functional groups in the bioreactor under different C/N conditions were analyzed by fluorescence excitation-emission matrix (EEM) spectra and Fourier transform infrared spectroscopy (FTIR), which revealed that metabolic activities of denitrifying bacteria were enhanced with the increase of C/N. The morphology and structure of bacteria immobilized by fungal pellets explored by scanning electron microscope (SEM) showed the filamentous porous fungal pellets loaded with bacteria. Community structure analysis by high-throughput sequencing demonstrated that strain GF3 might was the dominant strain in bioreactor.


Assuntos
Nitratos , Águas Residuárias , Bactérias , Reatores Biológicos , Desnitrificação , Nitrogênio
16.
Water Res ; 197: 117088, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33813172

RESUMO

A bacterium capable of complete ammonia oxidation (comammox) has been widely found in various environments, whereas its industrial application is limited due to the difficulty of cultivation and/or enrichment. We developed a biological system to produce a high-quality nitrate solution for use in hydroponic fertilizer. The system was composed of two separate reactors for ammonification and nitrification and was found to have a stable and efficient performance in the conversion of organic nitrogen to nitrate. To determine the key microbes involved and better understand the system, the microbial communities in the reactors were analyzed by 16S rRNA gene sequencing in combination with a shotgun metagenomic analysis. Canonical ammonia-oxidizing bacteria, which can only catalyze the oxidation of ammonia to nitrite, were detected with negligible relative abundances, while a comammox Nitrospira-related operational taxonomic unit (OTU) dominated the nitrification reactor. Furthermore, the comammox-type ammonia monooxygenase was found to be 500 times more highly expressed than the canonical one by quantitative PCR, indicating that comammox was the main driver of the stable and efficient ammonia oxidation in the system. A microbial co-occurrence analysis revealed a strong positive correlation between Nitrospira and several OTUs, some of which, such as Anaerolinea OTU, have been found to co-exist with comammox Nitrospira in the biofilms of water treatment systems. Given that these OTUs were abundant only on microbe-attached carriers in the system, their co-existence within the biofilm could be beneficial to stabilize the Nitrospira abundance, possibly by physically preventing oxygen exposure as well as cell spillage.


Assuntos
Nitratos , Águas Residuárias , Amônia , Archaea/genética , Bactérias/genética , Nitrificação , Nitrogênio , Oxirredução , Filogenia , RNA Ribossômico 16S/genética
17.
Cochrane Database Syst Rev ; 3: CD013122, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33784794

RESUMO

BACKGROUND: Approximately 40% to 95% of people with cirrhosis have oesophageal varices. About 15% to 20% of oesophageal varices bleed in about one to three years of diagnosis. Several different treatments are available, which include endoscopic sclerotherapy, variceal band ligation, beta-blockers, transjugular intrahepatic portosystemic shunt (TIPS), and surgical portocaval shunts, among others. However, there is uncertainty surrounding their individual and relative benefits and harms. OBJECTIVES: To compare the benefits and harms of different initial treatments for secondary prevention of variceal bleeding in adults with previous oesophageal variceal bleeding due to decompensated liver cirrhosis through a network meta-analysis and to generate rankings of the different treatments for secondary prevention according to their safety and efficacy. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and trials registers until December 2019 to identify randomised clinical trials in people with cirrhosis and a previous history of bleeding from oesophageal varices. SELECTION CRITERIA: We included only randomised clinical trials (irrespective of language, blinding, or status) in adults with cirrhosis and previous history of bleeding from oesophageal varices. We excluded randomised clinical trials in which participants had no previous history of bleeding from oesophageal varices, previous history of bleeding only from gastric varices, those who failed previous treatment (refractory bleeding), those who had acute bleeding at the time of treatment, and those who had previously undergone liver transplantation. DATA COLLECTION AND ANALYSIS: We performed a network meta-analysis with OpenBUGS using Bayesian methods and calculated the differences in treatments using hazard ratios (HR), odds ratios (OR) and rate ratios with 95% credible intervals (CrI) based on an available-case analysis, according to National Institute of Health and Care Excellence Decision Support Unit guidance. MAIN RESULTS: We included a total of 48 randomised clinical trials (3526 participants) in the review. Forty-six trials (3442 participants) were included in one or more comparisons. The trials that provided the information included people with cirrhosis due to varied aetiologies. The follow-up ranged from two months to 61 months. All the trials were at high risk of bias. A total of 12 interventions were compared in these trials (sclerotherapy, beta-blockers, variceal band ligation, beta-blockers plus sclerotherapy, no active intervention, TIPS (transjugular intrahepatic portosystemic shunt), beta-blockers plus nitrates, portocaval shunt, sclerotherapy plus variceal band ligation, beta-blockers plus nitrates plus variceal band ligation, beta-blockers plus variceal band ligation, sclerotherapy plus nitrates). Overall, 22.5% of the trial participants who received the reference treatment (chosen because this was the commonest treatment compared in the trials) of sclerotherapy died during the follow-up period ranging from two months to 61 months. There was considerable uncertainty in the effects of interventions on mortality. Accordingly, none of the interventions showed superiority over another. None of the trials reported health-related quality of life. Based on low-certainty evidence, variceal band ligation may result in fewer serious adverse events (number of people) than sclerotherapy (OR 0.19; 95% CrI 0.06 to 0.54; 1 trial; 100 participants). Based on low or very low-certainty evidence, the adverse events (number of participants) and adverse events (number of events) may be different across many comparisons; however, these differences are due to very small trials at high risk of bias showing large differences in some comparisons leading to many differences despite absence of direct evidence. Based on low-certainty evidence, TIPS may result in large decrease in symptomatic rebleed than variceal band ligation (HR 0.12; 95% CrI 0.03 to 0.41; 1 trial; 58 participants). Based on moderate-certainty evidence, any variceal rebleed was probably lower in sclerotherapy than in no active intervention (HR 0.62; 95% CrI 0.35 to 0.99, direct comparison HR 0.66; 95% CrI 0.11 to 3.13; 3 trials; 296 participants), beta-blockers plus sclerotherapy than sclerotherapy alone (HR 0.60; 95% CrI 0.37 to 0.95; direct comparison HR 0.50; 95% CrI 0.07 to 2.96; 4 trials; 231 participants); TIPS than sclerotherapy (HR 0.18; 95% CrI 0.08 to 0.38; direct comparison HR 0.22; 95% CrI 0.01 to 7.51; 2 trials; 109 participants), and in portocaval shunt than sclerotherapy (HR 0.21; 95% CrI 0.05 to 0.77; no direct comparison) groups. Based on low-certainty evidence, beta-blockers alone and TIPS might result in more, other compensation, events than sclerotherapy (rate ratio 2.37; 95% CrI 1.35 to 4.67; 1 trial; 65 participants and rate ratio 2.30; 95% CrI 1.20 to 4.65; 2 trials; 109 participants; low-certainty evidence). The evidence indicates considerable uncertainty about the effect of the interventions including those related to beta-blockers plus variceal band ligation in the remaining comparisons. AUTHORS' CONCLUSIONS: The evidence indicates considerable uncertainty about the effect of the interventions on mortality. Variceal band ligation might result in fewer serious adverse events than sclerotherapy. TIPS might result in a large decrease in symptomatic rebleed than variceal band ligation. Sclerotherapy probably results in fewer 'any' variceal rebleeding than no active intervention. Beta-blockers plus sclerotherapy and TIPS probably result in fewer 'any' variceal rebleeding than sclerotherapy. Beta-blockers alone and TIPS might result in more other compensation events than sclerotherapy. The evidence indicates considerable uncertainty about the effect of the interventions in the remaining comparisons. Accordingly, high-quality randomised comparative clinical trials are needed.


Assuntos
Varizes Esofágicas e Gástricas/complicações , Hemorragia Gastrointestinal/prevenção & controle , Cirrose Hepática/complicações , Metanálise em Rede , Derivação Portossistêmica Transjugular Intra-Hepática , Prevenção Secundária/métodos , Antagonistas de Receptores Adrenérgicos beta 2/uso terapêutico , Adulto , Viés , Varizes Esofágicas e Gástricas/mortalidade , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/mortalidade , Humanos , Ligadura/efeitos adversos , Ligadura/métodos , Transplante de Fígado/estatística & dados numéricos , Pessoa de Meia-Idade , Nitratos/uso terapêutico , Derivação Portossistêmica Transjugular Intra-Hepática/estatística & dados numéricos , Ensaios Clínicos Controlados Aleatórios como Assunto , Escleroterapia/efeitos adversos , Escleroterapia/mortalidade
18.
Sci Total Environ ; 776: 145939, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33647667

RESUMO

Certain metal ions can contribute to the functional microorganisms becoming dominant by stimulating their metabolism and activity. Therefore, Pseudomonas stutzeri T13 was used to investigate the impacts of biological stimulation with certain metal ions on aerobic denitrifying bacteria. Results showed that with the addition of 0.036 mmol/L Fe3+ ions, the nitrogen-assimilation capacity of P. stutzeri T13 significantly increased by 43.99% when utilizing ammonium as the sole nitrogen source. Kinetic models were applied to analyze the role of Fe3+ ions in the growth, and results indicated that increasing Fe3+ ion concentrations decreased the decay rate. The maximum nitrate reduction rate increased from 9.55 mg-N L-1 h-1 to 19.65 mg-N L-1 h-1 with Fe3+ ion concentrations increasing from 0.004 to 0.036 mmol/L, which was due to the increased level of napA gene transcription and activity of nitrate reductase. This study provides a theoretical foundation for further understanding of the mechanism of Fe3+ ion stimulation of aerobic denitrification, benefiting the practicable application of aerobic denitrifiers.


Assuntos
Compostos de Amônio , Pseudomonas stutzeri , Aerobiose , Desnitrificação , Compostos Férricos , Nitratos , Nitrogênio
19.
Nat Plants ; 7(3): 310-316, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33686225

RESUMO

The nitrate transporter NRT2.1, which plays a central role in high-affinity nitrate uptake in roots, is activated at the post-translational level in response to nitrogen (N) starvation1,2. However, the critical enzymes required for the post-translational activation of NRT2.1 remain to be identified. Here, we show that a type 2C protein phosphatase, designated CEPD-induced phosphatase (CEPH), activates high-affinity nitrate uptake by directly dephosphorylating Ser501 of NRT2.1, a residue that functions as a negative phospho-switch in Arabidopsis2. CEPH is predominantly expressed in epidermal and cortex cells in roots and is upregulated by N starvation via a CEPDL2/CEPD1/2-mediated long-distance signalling from shoots3,4. The loss of CEPH leads to marked decreases in high-affinity nitrate uptake, tissue nitrate content and plant biomass. Collectively, our results identify CEPH as a crucial enzyme in the N-starvation-dependent activation of NRT2.1 and provide molecular and mechanistic insights into how plants regulate high-affinity nitrate uptake at the post-translational level in response to the N environment.


Assuntos
Proteínas de Transporte de Ânions/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Nitratos/metabolismo , Arabidopsis/enzimologia , Glutarredoxinas/metabolismo , Fosforilação , Serina/metabolismo
20.
Plant Sci ; 306: 110862, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33775367

RESUMO

For rapid growth, moso bamboo (Phyllostachys edulis) requires large amounts of nutrients. Nitrate is an indispensable molecular signal to regulate nitrogen absorption and assimilation, which are regulated by group III NIN-LIKE PROTEINs (NLPs). However, no Phyllostachys edulis NLP (PeNLP) has been characterized. Here, eight PeNLPs were identified, which showed dynamic expression patterns in bamboo tissues. Nitrate did not affect PeNLP mRNA levels, and PeNLP1, -2, -5, -6, -7, and -8 successfully restored nitrate signaling in Arabidopsis atnlp7-1 protoplasts through recovering AtNiR and AtNRT2.1 expression. Four group I and II PeNLPs (PeNLP1, -2, -5, and -8) interacted with the nitrate-responsive cis-element of PeNiR. Moreover, nitrate triggered the nuclear retention of PeNLP8. PeNLP8 overexpression in Arabidopsis significantly increased the primary root length, lateral root number, leaf area, and dry and wet weight of the transgenic plants, and PeNLP8 expression rescued the root architectural defect phenotype of atnlp7-1 mutants. Interestingly, PeNLP8 overexpression dramatically reduced nitrate content but elevated total amino acid content in Arabidopsis. Overall, the present study unveiled the potential involvement of group I and II NLPs in nitrate signaling regulation and provided genetic resources for engineering plants with high nitrogen use efficiency.


Assuntos
Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Nitratos/metabolismo , Proteínas de Plantas/metabolismo , Poaceae/genética , Poaceae/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Genes de Plantas , Genoma de Planta , Mutação , Filogenia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas/genética
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