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1.
Food Chem ; 343: 128397, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33406569

RESUMO

Chocolate is an important source of free bioactive amines and amino acids which play important roles in human health. Considering the limited information on the bioaccessibility of these compounds from chocolate, the objective of this study was to characterize their profiles and bioaccessibility in 70% cocoa dark chocolate through in vitro simulation of oral, gastric and intestinal digestions. Seven amines were detected; polyamines were predominant before in vitro digestion, whereas tyramine, cadaverine and spermidine after digestion. All amines showed high bioaccessibility with slight influence of digestive enzymes. Amines increased after gastrointestinal digestion: tyramine (13-fold), tryptamine (9-fold), others (2.4-4.2-fold) and histamine appeared. All amino acids, GABA and ammonia were detected in chocolate, and their contents increased after in vitro digestion due to digestive enzymes (4.6, 2.8 and 2.1, respectively). Dark chocolate protein is a good source of tryptophan, phenylalanine + tyrosine, isoleucine, histidine, but limiting for lysine, leucine, and threonine.


Assuntos
Aminas/metabolismo , Aminoácidos/metabolismo , Cacau/metabolismo , Chocolate/análise , Aminas/análise , Aminoácidos/análise , Amônia/metabolismo , Cacau/química , Cromatografia Líquida de Alta Pressão , Análise por Conglomerados , Histamina/análise , Histamina/metabolismo , Humanos , Valor Nutritivo , Poliaminas/análise , Poliaminas/metabolismo , Análise de Componente Principal , Ácido gama-Aminobutírico/análise
2.
Chemosphere ; 262: 127932, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32805662

RESUMO

Zeolite addition has been widely suggested for its ability to overcome ammonia stress occurring during anaerobic digestion. However little is known regarding the underlying mechanisms of mitigation and especially how zeolite influences the microbial structuration. The aim of this study was to bring new contributions on the effect of zeolite on the microbial community arrangement under a low ammonia stress. Replicated batch experiments were conducted. The microbial population was characterised with 16S sequencing. Methanogenic pathways were identified with methane isotopic fractionation. In presence of ammonia, zeolite mitigated the decrease of biogas production rate. Zeolite induced the development of Izimaplasmatales order and preserved Peptococcaceae family members, known as propionate degraders. Moreover methane isotopic fractionation showed that hydrogenotrophic methanogenesis was maintained in presence of zeolite under ammonia low stress. Our results put forward the benefit of zeolite to improve the bacteria-archaea syntrophy needed for propionate degradation and methane production under a low ammonia stress.


Assuntos
Alimentos , Eliminação de Resíduos , Zeolitas/química , Amônia/metabolismo , Anaerobiose , Archaea/metabolismo , Bactérias/metabolismo , Biocombustíveis , Reatores Biológicos , Metano/metabolismo , Microbiota , Propionatos/metabolismo
3.
Chemosphere ; 263: 127934, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32828055

RESUMO

A high ammonia concentration and chemical oxygen demand (COD) in piggery wastewater force it to be diluted before conventional microalgal treatment to reduce ammonia toxicity. Incomplete treatment of ammonia and COD in piggery wastewater may cause eutrophication, resulting in algal blooms. This study tried to treat raw piggery wastewater without dilution, using three strains of microalgae (Chlorella sorokiniana, Coelastrella sp. and Acutodesmus nygaardii) that outcompeted other algae under heterotrophic, mixotrophic, and autotrophic conditions, respectively, through adaptive evolution at high ammonia concentration. The three stepwise processes were designed to remove (1) small particles, COD, and phosphorus in the 1st heterotrophic C. sorokiniana cultivation, (2) ammonia and COD in the 2nd mixotrophic Coelastrella sp. cultivation, and (3) the remaining ammonia in the 3rd photoautotrophic A. nygaardii cultivation. To enhance ammonia uptake rate, each algal species were inoculated after 2-day nitrogen starvation. When the N-starved three species were inoculated at each step sequentially at 7 g/L for 2 days, the final phosphorus, COD, and ammonia removal efficiencies were 100% (16.4-0 mg/L), 92% (6820-545 mg/L), 90% (850-81 mg/L) and turbidity (99%) after total 6 days.


Assuntos
Adaptação Fisiológica/fisiologia , Amônia/metabolismo , Biodegradação Ambiental , Microalgas/fisiologia , Eliminação de Resíduos Líquidos/métodos , Animais , Processos Autotróficos , Análise da Demanda Biológica de Oxigênio , Biomassa , Chlorella , Processos Heterotróficos , Nitrogênio , Fósforo , Suínos , Águas Residuárias
4.
Anim Sci J ; 91(1): e13481, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33161615

RESUMO

This study investigated the effect of adaptation to grazing in early spring on herbage intake, ruminal fermentation parameters, blood metabolite concentrations, and body weight change in dairy cows. The experiment was conducted on eight rumen-cannulated non-lactating cows in the early spring period. Four cows were adapted to grazing by stocking for 4 hr for 1 week (ADP group). The other cows were kept in a barn during the period (CON group). Then, both groups of cows were stocked together throughout a day on a 1 ha pasture for 3 weeks (experimental period). In the first week of the experimental period, compared to the CON group, the ADP group had a higher herbage intake, ruminal NH3 -N and total VFA concentration, and blood urea concentration, but the NEFA concentration was lower in the ADP group (p < .01). During the subsequent weeks, there were little differences in ruminal fermentation parameters and blood metabolites. Cows in the ADP group maintained their body weight, but cows in the CON group lost 60 kg of body weight in the first week of the experimental period.


Assuntos
Adaptação Fisiológica/fisiologia , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Peso Corporal , Bovinos/metabolismo , Bovinos/fisiologia , Ingestão de Alimentos/fisiologia , Fermentação , Herbivoria/fisiologia , Rúmen/metabolismo , Estações do Ano , Amônia/metabolismo , Animais , Nitrogênio da Ureia Sanguínea , Feminino , Nitrogênio/metabolismo , Fatores de Tempo
5.
PLoS One ; 15(10): e0239736, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002008

RESUMO

The identification of anammox bacteria is mostly relied on PCR with various marker genes. However, the community composition revealed by different marker genes and whether the marker genes influence the resulted community composition remain unclear. We compared the community structure of anammox bacteria in enriched and natural environments revealed by 16S rRNA and functional genes (hzo, hzsA and hzsB) from public database and published papers. The genus of Ca. Scalindua showed the lowest similarities with other genera, especially for the hzsA gene (66.9%-68.6%). The 16S rRNA gene is the most commonly used marker gene in natural habitats with 151 out 221 papers in total. The anammox bacterial community composition is distributed according to the source of habitat regardless the use of various marker genes. The role of marker gene is limited with explanatory of 5.4% for variance of community composition, versus 20.5% of habitat. The effect of marker gene is mainly acted on freshwater habitat, which shows significant different community composition revealed by 16S rRNA and hzo, with Ca. Brocadia and Ca. Jettenia as dominant genus, respectively.


Assuntos
Amônia/metabolismo , Bactérias Anaeróbias/genética , Genes Bacterianos/genética , Viés , Ecossistema , Marcadores Genéticos/genética , Reação em Cadeia da Polimerase/métodos , RNA Ribossômico 16S/genética
6.
Nat Commun ; 11(1): 5090, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33037220

RESUMO

Six CO2 fixation pathways are known to operate in photoautotrophic and chemoautotrophic microorganisms. Here, we describe chemolithoautotrophic growth of the sulphate-reducing bacterium Desulfovibrio desulfuricans (strain G11) with hydrogen and sulphate as energy substrates. Genomic, transcriptomic, proteomic and metabolomic analyses reveal that D. desulfuricans assimilates CO2 via the reductive glycine pathway, a seventh CO2 fixation pathway. In this pathway, CO2 is first reduced to formate, which is reduced and condensed with a second CO2 to generate glycine. Glycine is further reduced in D. desulfuricans by glycine reductase to acetyl-P, and then to acetyl-CoA, which is condensed with another CO2 to form pyruvate. Ammonia is involved in the operation of the pathway, which is reflected in the dependence of the autotrophic growth rate on the ammonia concentration. Our study demonstrates microbial autotrophic growth fully supported by this highly ATP-efficient CO2 fixation pathway.


Assuntos
Desulfovibrio desulfuricans/crescimento & desenvolvimento , Desulfovibrio desulfuricans/metabolismo , Glicina/metabolismo , Trifosfato de Adenosina/metabolismo , Amônia/metabolismo , Processos Autotróficos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Dióxido de Carbono/metabolismo , Desulfovibrio desulfuricans/genética , Perfilação da Expressão Gênica , Genoma Bacteriano , Metabolômica
7.
Chemosphere ; 261: 128199, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113666

RESUMO

A microalgal-bacterial membrane photobioreactor (MB-MPBR) was developed for simultaneous COD and nutrients (N and P) removals from synthetic municipal wastewater in a single stage for a long-term operation over 350 days. The effects of hydraulic retention time (HRT) and N/P ratio on the biological performance were systematically evaluated for the first time. The results showed that a lower N/P ratio (3.9:1) and shorter HRT (2 d) promoted more biomass production, as compared to a high HRT (3 d) and a high N/P ratio (9.7:1). The highest biomass concentration (2.55 ± 0.14 g L-1) and productivity (127.5 mg L-1·d-1) were achieved at N/P ratio of 3.9:1 and HRT of 2 d due to the highest nitrogen and phosphorus loadings under such conditions. A COD and ammonia-N removal efficiency of over 96% and 99%, respectively, were achieved regardless of HRTs and N/P ratios. In the absence of nitrogen or phosphorus deficiency, shorter HRT (2 d) yielded a higher nitrogen and phosphorus uptake but lower removal efficiency. In addition, the imbalance N/P ratio (9.7:1) would decrease nitrogen or phosphorus removal. Overall, the results suggested that it was feasible to simultaneously achieve complete or high removal of COD, nitrogen, and phosphorous in MB-MPBR under the appropriate conditions. This study demonstrated for the first time that MB-MPBR is a promising technology that could achieve a high-quality effluent meeting the discharge standards of COD and nutrients in one single step.


Assuntos
Nitrogênio/metabolismo , Fósforo/metabolismo , Fotobiorreatores , Eliminação de Resíduos Líquidos/instrumentação , Amônia/metabolismo , Análise da Demanda Biológica de Oxigênio , Biomassa , Chlorella vulgaris/metabolismo , Microalgas/metabolismo , Nitrogênio/análise , Fotobiorreatores/microbiologia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química
8.
Chemosphere ; 261: 128108, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113640

RESUMO

Biotransformation of 6:2 fluorotelomer sulfonate (FTS) results in the formation of short-chain (C4 - C6) perfluorocarboxylic acids (PFCAs) in landfill leachate. Although leachate substrate concentrations (i.e., organic carbon, ammonia) vary widely, their effects on 6:2 FTS biotransformation and PFCAs formation are unknown. This study investigated the effect of organic carbon and ammonia concentration in 6:2 FTS aerobic biotransformation and PFCA formation in leachate. Biotransformation experiments were conducted with sediment collected from a landfill leachate ditch, to which deionized (DI) water and various amounts of leachate were added. Microbial community analysis using 16S rRNA indicated that while phylum Proteobacteria dominated the bacterial composition throughout the 60 days, Actinobacteria increased with time. Many genera from Proteobacteria and Actinobacteria can synthesize a wide array of enzymes, indicating that these phyla are likely to play an important role in 6:2 FTS biotransformation. Higher biotransformation of 6:2 FTS was observed in leachate-added microcosms (∼21%), compared to DI water microcosm (∼14%), likely reflecting the substrate dependency of 6:2 FTS biotransformation. Substrate limiting conditions in DI water microcosm resulted in slightly greater formation of ∑(C4 - C6) PFCAs (∼14 mol%), compared with leachate added microcosms (10-13 mol%). The findings suggest that dilution of landfill leachate, (e.g., during wet seasons), likely results in reduced 6:2 FTS biotransformation and increased PFCAs formation compared to dry conditions. Observed formation of C7 - C8 PFCAs in the live microcosms suggested that landfills act as secondary sources of legacy PFCAs (e.g., perfluorooctanoic acid) in the environment.


Assuntos
Actinobacteria/metabolismo , Alcanossulfonatos/metabolismo , Caprilatos/metabolismo , Fluorcarbonetos/metabolismo , Proteobactérias/metabolismo , Actinobacteria/genética , Aerobiose , Alcanossulfonatos/análise , Amônia/metabolismo , Biotransformação , Caprilatos/análise , Fluorcarbonetos/análise , Microbiota/genética , Modelos Teóricos , Proteobactérias/genética , RNA Ribossômico 16S/genética , Estações do Ano , Instalações de Eliminação de Resíduos , Poluentes Químicos da Água/metabolismo
9.
Chemosphere ; 261: 128051, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113650

RESUMO

The potential toxicity of copper nanoparticles (CuNPs) to early stages of fishes is not fully understood, and little is known about their effects on ionocytes and associated functions. This study used zebrafish embryos as a model to investigate the toxic effects of CuNPs on two subtypes of ionocytes. Zebrafish embryos were exposed to 0.1, 1, and 3 mg L-1 CuNPs for 96 h. After exposure, whole-body Na+ and Ca2+ contents were significantly reduced at ≥0.1 mg L-1, while the K+ content had decreased at ≥1 mg L-1. H+ and NH4+ excretion by the skin significantly decreased at ≥1 mg L-1. The number of living ionocytes labeled with rhodamine-123 had significantly decreased with ≥0.1 mg L-1 CuNPs. The ionocyte subtypes of H+-ATPase-rich (HR) and Na+/K+-ATPase-rich (NaR) cells were labeled by immunostaining and had decreased with ≥1 mg L-1. Shrinkage of the apical opening of ionocytes was revealed by scanning electronic microscopy. Functional impairment was also reflected by changes in gene expressions, including ion transporters/channels and Ca2+-regulatory hormones. This study shows that CuNP exposure can impair two subtypes of ionocytes and their associated functions, including Na+/Ca2+ uptake and H+/NH4+ excretion in zebrafish embryos.


Assuntos
Amônia/metabolismo , Cobre/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Nanopartículas/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Ácidos/metabolismo , Animais , Transporte Biológico , Cálcio/metabolismo , Cobre/metabolismo , Embrião não Mamífero/metabolismo , Canais Iônicos/metabolismo , Íons/metabolismo , Nanopartículas/metabolismo , Pele/metabolismo , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/metabolismo , Proteínas de Peixe-Zebra/metabolismo
10.
PLoS One ; 15(9): e0238531, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877444

RESUMO

Along with urbanization, the intensified nitrogen pollution in urban rivers and the form of black-odor rivers has become one of the biggest concerns. Better understanding of the nitrogen transformations and microbial mechanisms occurring within urban rivers could help to manage their water quality. In this study, pollution characteristics, potential nitrogen removal rate, composition and function of bacterial community, and abundance of functional genes associated with nitrogen transformation were comparatively investigated in a typical urban river (FC) and a suburban river (LH). Compared with LH, FC was characterized by higher content of nutrients, lower potential nitrogen removal rate and lower abundance of functional genes associated with nitrogen transformation in both overlying water and sediment, especially in summer. Sediment dissolved organic matter characterized by excitation-emission matrix (EEM) showed that FC was more severely polluted by high nitrogen organic matter. Our results revealed that anammox was the main nitrogen removal pathway in both rivers and potential nitrogen removal rates decreased significantly in summer. Bacterial community analysis showed that the benthic communities were more severely influenced by the pollutant than aquatic ones in both rivers. Furthermore, the FC benthic community was dominated by anaerobic respiring, fermentative, sulfate reduction bacteria. Quantitatively, the denitrification rate showed a significant positive correlation with the abundance of denitrification genes, whilst the anammox rate was significantly negatively correlated with bacterial diversity. Meanwhile, NH4+-N had a significant negative correlation to both denitrification and anammox in sediment. Taken together, the results indicated that the increased nitrogen pollutants in an urban river altered nitrogen removal pathways and bacterial communities, which could in turn exacerbate the nitrogen pollution to this river.


Assuntos
Bactérias/genética , Genes Bacterianos , Nitrogênio/metabolismo , Rios/microbiologia , Urbanização , Amônia/metabolismo , Anaerobiose , Desnitrificação/genética , Sedimentos Geológicos/química , Oxirredução , Filogenia , RNA Ribossômico 16S/genética , Estações do Ano , Qualidade da Água
11.
PLoS One ; 15(9): e0229880, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966333

RESUMO

Aerobic composting is a sustainable method for chicken manure recycling, while its unsuitable porosity and carbon to nitrogen ratio (C/N) may result in high nitrogen loss and incomplete composting. With the aim to investigate the effects of carbon-based additives and two ventilation rates on chicken manure composting and microbial community, two series of treatments were set up for chicken manure composting, in order to investigate their effects on the biodegradation process, ammonia (NH3) emission, nitrogen loss, physiochemical properties and microbial community. The results showed that additives and ventilation rates set in the current study influenced the carbon dioxide (CO2) production from the 2nd week and also the physiochemical parameters during the entire process, while no inhibitory effect on the maturity were observed. With woody peat as additive, the NH3 emission amount and nitrogen loss rate were shown as 15.86 mg and 4.02%, less than those in other treatments, 31.08-80.13 mg and 24.26-34.24%, respectively. The high aeration rate increased the NH3 emission and nitrogen loss, which were varied when the additives were different. The terminal restriction fragment length polymorphism (T-RFLP) results showed that the additives and the ventilation rates changed the microbial community, while the prominent microbial clones belonged to the class of Bacilli and Clostridia (in the phylum of Firmicutes), and Alphaproteobacteria, Deltaproteobacteria and Gammaproteobacteria (in the phylum of Proteobacteria). Bacillus spp. was observed to be the most dominant bacteria in all the composting stages and treatments. It was concluded that woody peat could improve chicken manure composting more than other additives, especially on reducing nitrogen loss, meanwhile 0.18 L‧min-1‧kg-1 DM was suitable for various additives. Therefore, suitable additive and aeration rate could be used in practical application, which could significantly reduce nitrogen loss without influence on the compos maturity process.


Assuntos
Amônia/metabolismo , Compostagem/métodos , Esterco/microbiologia , Microbiota/fisiologia , Nitrogênio/metabolismo , Amônia/análise , Animais , Bactérias/genética , Bactérias/isolamento & purificação , Carbono/metabolismo , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Galinhas , DNA Bacteriano/isolamento & purificação , Nitrogênio/análise , Porosidade , Ventilação/métodos
12.
Chemosphere ; 261: 127775, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32738717

RESUMO

The short-term effects of Mn2O3 nanoparticles (NPs) were examined for nitrifying bacterial enrichments exposed under low and high dissolved oxygen (DO) conditions using substrate (ammonia) specific oxygen uptake rates (sOUR), reverse transcriptase - quantitative polymerase chain reaction (RT-qPCR) assays, and by analysis of 16S rRNA sequences. Samples from nitrifying bioreactor were exposed in batch vessels to Mn2O3 NPs (1, 5 and 10 mg/L) for either 1 or 3 h under no additional aeration or 0.25 L/min aeration. There was increase in nitrification inhibition as determined by sOUR with increasing dosages of Mn2O3 NPs for both low and high DO. At 10 mg/L Mn2O3 NPs, the inhibition was about 7-10% for 1 and 3 h exposure in both cases. There was notable reduction in the transcript levels of amoA, hao and nirK for 10 mg/L of Mn2O3 NPs under 3 h, high DO exposure, which corresponded well with sOUR. The 16S rRNA sequencing showed that there was an inhibitory effect on ammonia oxidizers activity upon exposure to 10 mg/L of Mn2O3 NPs. Collectively, the findings in this study advanced understanding of the different effects of Mn2O3 NPs on nitrifying bacteria.


Assuntos
Nanopartículas/toxicidade , Nitrificação/fisiologia , Amônia/metabolismo , Bactérias/metabolismo , Reatores Biológicos/microbiologia , Expressão Gênica , Nitrificação/efeitos dos fármacos , Oxirredução , Oxigênio/metabolismo , RNA Ribossômico 16S/genética
13.
Aquat Toxicol ; 226: 105585, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32763644

RESUMO

Although excess ammoniacal-nitrogen (NH4+-N) results in the disturbance of various important biochemical and physiological processes, a detailed study on the effects of NH4+-N stress on the photosynthesis and global changes in protein levels in submerged macrophytes is still lacking. Here, the changes of excess NH4+-N on physiological parameters in Hydrilla verticillata (L.f.) Royle, a submerged macrophyte were investigated, including the contents of photosynthetic pigments, soluble sugars, net photosynthesis and respiration, glutamine synthetase (GS) and glutamate synthase (GOGAT) activities, chloroplast ultrastructure, chloroplast reactive oxygen species (ROS) accumulation and protein levels. Our results showed that the net photosynthetic rate and pigment content reached maximum values when the plants were treated with 1 and 2 mg L-1 NH4+-N, respectively, and decreased at NH4+-N concentrations at 5, 10, 15 and 20 mg L-1. This decrease might be caused by ROS accumulation. Compared that in 0.02 mg L-1 NH4+-N as a control, ROS generation in chloroplasts significantly increased in the presence of more than 2 mg L-1 NH4+-N. Consistently, the damages caused by over-accumulated ROS were observed in chloroplast ultrastructure, showing a loose thylakoid membranes and swollen grana/stroma lamellae. Furthermore, through proteomic analysis, we identified 91 differentially expressed protein spots. Among them, six proteins involved in photosynthesis decreased in abundance in response to excess NH4+-N. Surprisingly, the abundance of all the identified proteins that were involved in nitrogen assimilation and amino acid metabolism tended to increase under excess NH4+-N compared with the control, suggestive of the imbalanced carbon and nitrogen (C-N) metabolisms. In support, activated GS and GOGAT cycle was observed, evidenced by higher activities of GS and GOGAT enzymes. To our knowledge, this work is the first description that excess NH4+-N results in chloroplast ultrastructural damages and the first proteomic evidence to support that excess NH4+-N can lead to a decline in photosynthesis and imbalance of C-N metabolism in submerged macrophytes.


Assuntos
Amônia/toxicidade , Cloroplastos/ultraestrutura , Hydrocharitaceae/efeitos dos fármacos , Nitrogênio/toxicidade , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/toxicidade , Amônia/metabolismo , Carbono/metabolismo , Cloroplastos/efeitos dos fármacos , Hydrocharitaceae/metabolismo , Nitrogênio/metabolismo , Proteômica , Poluentes Químicos da Água/metabolismo
14.
Ecotoxicol Environ Saf ; 205: 111050, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32827960

RESUMO

Ammonia toxicity to respiratory system in pig faming is of particular concern, but the molecular mechanism remains still unclear. The present study was devoted to assess the impacts of the ammonia exposure on the lung tissues based on a pig study using 80 ppm ammonia exposing to piglets for different days. The histology analysis revealed ammonia exposure induced lung injury and inflammatory response, as indicated by epithelial-mesenchymal transition (EMT), significant thickening of alveolar septa, infiltration of inflammatory cells and excessive mucus production. The transcriptome analysis revealed many more up-regulated genes in exposure groups when compared with the control group, and these genes were significantly enriched in the GO term of extracellular exosome, proteolysis, and regulation of circadian rhythm. The study discovered the induction of seven genes (CRY2, CIART, CREM, NR1D1, NR1D2, PER1 and PER3) that encode repressors of circadian clock. One gene (ARNTL) that encodes activator of circadian clock was down-regulated after ammonia exposure. The results of this study suggest that ammonia exposure disturbed the pulmonary circadian clock gene expression, which may establish new evidence for further understanding the toxicity of ammonia to lungs.


Assuntos
Amônia/toxicidade , Relógios Circadianos/efeitos dos fármacos , Lesão Pulmonar , Amônia/metabolismo , Animais , Relógios Circadianos/genética , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/genética , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Pulmão/metabolismo , Suínos , Fatores de Transcrição/genética , Regulação para Cima
15.
Am J Physiol Renal Physiol ; 319(3): F366-F379, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32657159

RESUMO

Carbonic anhydrase (CAII) binds to the electrogenic basolateral Na+-[Formula: see text] cotransporter (NBCe1) and facilitates [Formula: see text] reabsorption across the proximal tubule. However, whether the inhibition of CAII with acetazolamide (ACTZ) alters NBCe1 activity and interferes with the ammoniagenesis pathway remains elusive. To address this issue, we compared the renal adaptation of rats treated with ACTZ to NH4Cl loading for up to 2 wk. The results indicated that ACTZ-treated rats exhibited a sustained metabolic acidosis for up to 2 wk, whereas in NH4Cl-loaded rats, metabolic acidosis was corrected within 2 wk of treatment. [Formula: see text] excretion increased by 10-fold in NH4Cl-loaded rats but only slightly (1.7-fold) in ACTZ-treated rats during the first week despite a similar degree of acidosis. Immunoblot experiments showed that the protein abundance of glutaminase (4-fold), glutamate dehydrogenase (6-fold), and SN1 (8-fold) increased significantly in NH4Cl-loaded rats but remained unchanged in ACTZ-treated rats. Na+/H+ exchanger 3 and NBCe1 proteins were upregulated in response to NH4Cl loading but not ACTZ treatment and were rather sharply downregulated after 2 wk of ACTZ treatment. ACTZ causes renal [Formula: see text] wasting and induces metabolic acidosis but inhibits the upregulation of glutamine transporter and ammoniagenic enzymes and thus suppresses ammonia synthesis and secretion in the proximal tubule, which prevented the correction of acidosis. This effect is likely mediated through the inhibition of the CA-NBCe1 metabolon complex, which results in cell alkalinization. During chronic ACTZ treatment, the downregulation of both NBCe1 and Na+/H+ exchanger 3, along with the inhibition of ammoniagenesis and [Formula: see text] generation, contributes to the maintenance of metabolic acidosis.


Assuntos
Acetazolamida/farmacologia , Acidose/metabolismo , Amônia/metabolismo , Bicarbonatos/metabolismo , Diuréticos/farmacologia , Rim/efeitos dos fármacos , Acetazolamida/farmacocinética , Equilíbrio Ácido-Base/efeitos dos fármacos , Adaptação Fisiológica , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Animais , Cloretos/sangue , Diuréticos/farmacocinética , Eletrólitos/sangue , Regulação da Expressão Gênica/efeitos dos fármacos , Meia-Vida , Rim/metabolismo , Rim/patologia , Masculino , Ratos , Ratos Sprague-Dawley , Urinálise
16.
Chemosphere ; 259: 127504, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650170

RESUMO

Hexafluoropropylene oxide (HFPO) homologues, as emerging perfluoroalkyl substances (PFASs) to replace legacy PFASs, have wide applications in the organofluorine industry and have been detected in the global environment. However, it is still unclear what effect HFPO homologues will exert on microbial abundance, community structure and function. The objective of this study was to assess potential impacts of HFPO homologue acids on archaea, bacteria, and ammonia-oxidizing archaea (AOA) and bacteria (AOB) in the soil environment. Grassland soil microcosms were supplemented with low (0.1 mg/kg) or high (10 mg/kg) dosages of dimer, trimer and tetramer acids of HFPO (HFPO-DA, HFPO-TA, and HFPO-TeA), respectively. The amendment of HFPO homologues acids initially decreased the abundance of archaea and bacteria but increased them in the later period. The addition of HFPO homologues acids raised AOA abundance but restrained AOB growth during the whole incubation. AOA and AOB community structures showed considerable variations. Potential nitrifying rate (PNR) showed an increase in the initial period followed by a decline in the later period. HFPO-DA had a lasting and suppressive effect on AOB and PNR even at a nearly environmental level. Overall, HFPO homologues with different carbon chain lengths had different impacts on soil microbial community and ammonia oxidation.


Assuntos
Fluorcarbonetos/farmacologia , Microbiota/efeitos dos fármacos , Óxidos/farmacologia , Microbiologia do Solo , Solo/química , Amônia/metabolismo , Archaea/efeitos dos fármacos , Archaea/metabolismo , Bactérias/efeitos dos fármacos , Bactérias/metabolismo , Nitrificação , Oxirredução
17.
Nat Biomed Eng ; 4(9): 853-862, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32632226

RESUMO

Patients with kidney failure commonly require dialysis to remove nitrogenous wastes and to reduce burden to the kidney. Here, we show that a bacterial cocktail orally delivered in animals with kidney injury can metabolize blood nitrogenous waste products before they diffuse through the intestinal mucosal barrier. The microbial cocktail consists of three strains of bacteria isolated from faecal microbiota that metabolize urea and creatinine into amino acids, and is encapsulated in calcium alginate microspheres coated with a polydopamine layer that is selectively permeable to small-molecule nitrogenous wastes. In murine models of acute kidney injury and chronic kidney failure, and in porcine kidney failure models, the encapsulated microbial cocktail significantly reduced urea and creatinine concentrations in blood, and did not lead to any adverse effects.


Assuntos
Enteroadsorção/métodos , Microbiota , Compostos de Nitrogênio/isolamento & purificação , Insuficiência Renal/terapia , Administração Oral , Alginatos/química , Amônia/metabolismo , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Cápsulas/administração & dosagem , Cápsulas/química , Creatinina/metabolismo , Modelos Animais de Doenças , Fezes/microbiologia , Indóis/química , Camundongos , Microfluídica , Microesferas , Compostos de Nitrogênio/metabolismo , Polímeros/química , Suínos , Resultado do Tratamento , Ureia/metabolismo
18.
Chemosphere ; 257: 127250, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32600781

RESUMO

Widespread use of gadolinium-based contrast agents in medical imaging has resulted in increased Gd inputs to municipal wastewater treatment plants. Others have reported that typical wastewater treatment does not attenuate Gd, resulting in discharges to natural waters. However, whether elevated Gd impacts the performance of biological treatment has not been investigated. We examined whether gadolinium chloride or Gd chelated with diethylenetriaminepentaacetic acid (DTPA) affected the activity of the model nitrifying bacterium Nitrosomonas europaea. At nominal GdCl3 additions ranging from 1 to 500 µM, no impact was observed compared to the control. Most (>98%) of the added Gd precipitated, and extracellular GdPO4 nanoparticles were observed. When chelated with DTPA, Gd remained soluble, but no statistically significant impact on ammonia oxidation was observed until the highest concentrations tested. At 300 and 500 µM Gd-DTPA, a temporary reduction of nitrite production relative to the control (effect size 1.3 mg l-1 and 1.5 mg l-1, respectively, at 24 h) was seen. By itself, DTPA was highly inhibitory. Modeling suggested that DTPA likely chelated other metals, but adjusting the concentrations of the most abundant metals in the medium, calcium and magnesium, indicated that lowering their free ion activities was probably not the cause of inhibition. Complexation of other essential metals was more likely. Our studies indicate that while the low bioavailability of Gd may limit its ecosystem impacts, the role of synthetic ligands used with Gd and other rare earth elements should be considered as the production, use and disposal of these elements increases.


Assuntos
Amônia/metabolismo , Gadolínio/toxicidade , Nitrosomonas europaea/metabolismo , Poluentes Químicos da Água/metabolismo , Ecossistema , Gadolínio DTPA , Metais Terras Raras , Nitritos , Nitrosomonas , Oxirredução , Águas Residuárias
19.
Nat Commun ; 11(1): 3511, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665599

RESUMO

In the context of continuously increasing anthropogenic nitrogen inputs, knowledge of how ammonia oxidation (AO) in the ocean responds to warming is crucial to predicting future changes in marine nitrogen biogeochemistry. Here, we show divergent thermal response patterns for marine AO across a wide onshore/offshore trophic gradient. We find ammonia oxidizer community and ambient substrate co-regulate optimum temperatures (Topt), generating distinct thermal response patterns with Topt varying from ≤14 °C to ≥34 °C. Substrate addition elevates Topt when ambient substrate is unsaturated. The thermal sensitivity of kinetic parameters allows us to predict responses of both AO rate and Topt at varying substrate and temperature below the critical temperature. A warming ocean promotes nearshore AO, while suppressing offshore AO. Our findings reconcile field inconsistencies of temperature effects on AO, suggesting that predictive biogeochemical models need to include such differential warming mechanisms on this key nitrogen cycle process.


Assuntos
Amônia/metabolismo , Mudança Climática , Microbiota/fisiologia , Oxirredução , Temperatura
20.
Am J Gastroenterol ; 115(7): 989-1002, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32618647

RESUMO

Management of hepatic encephalopathy (HE) remains challenging from a medical and psychosocial perspective. Members of the International Society for Hepatic Encephalopathy and Nitrogen Metabolism recognized 5 key unresolved questions in HE management focused on (i) driving, (ii) ammonia levels in clinical practice, (iii) testing strategies for covert or minimal HE, (iv) therapeutic options, and (v) nutrition and patient-reported outcomes. The consensus document addresses these topical issues with a succinct review of the literature and statements that critically evaluate the current science and practice, laying the groundwork for future investigations.


Assuntos
Encefalopatia Hepática/diagnóstico , Encefalopatia Hepática/terapia , Amônia/metabolismo , Condução de Veículo , Encefalopatia Hepática/metabolismo , Encefalopatia Hepática/fisiopatologia , Humanos , Apoio Nutricional , Medidas de Resultados Relatados pelo Paciente , Prognóstico , Sociedades Médicas
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