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1.
J Agric Food Chem ; 68(4): 1079-1090, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31885263

RESUMO

This study aimed to estimate the dietary risk of nitrates and nitrites in vegetables based on internal dose in a probabilistic manner by integrating exogenous exposure based on measured concentrations in vegetables with endogenous exposure using a toxicokinetic (TK) model. We optimized and validated a previous TK model and incorporated Monte Carlo simulations to account for variability across different age populations for predicting internal dose. High levels of nitrates were detected in leafy vegetables (from 545 ± 274 to 1641 ± 873 mg/kg). Nitrite contents of vegetables were generally low (from 1.26 ± 1.40 to 8.20 ± 14.1 mg/kg). The dietary risk was found to be different based on internal versus external dose, suggesting that it is critical to include endogenous nitrite formation into risk assessment. Nitrate and nitrite exposure from vegetables is unlikely to result in appreciable risks for most populations but may be a potential risk for preschoolers.


Assuntos
Nitratos/metabolismo , Nitritos/metabolismo , Verduras/química , Verduras/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Dieta , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Nitratos/toxicidade , Nitritos/toxicidade , Medição de Risco , Toxicocinética , Adulto Jovem
2.
Sci Total Environ ; 701: 134730, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31726404

RESUMO

A new nitrite accumulation pathway was discovered in the nitrogen conversion process of Arthrobacter arilaitensis. The extracellular nitrite reached 0.65 and 43.66 mg/L with hydroxylamine and nitrate as the sole nitrogen source, respectively. The enzyme activities of ammonia monooxygenase, hydroxylamine oxidoreductase and nitrate reductase were 0.42, 0.0014 and 0.0049 U/mg protein, respectively. The activity of nitrite reductase was completely inhibited by diethyldithiocarbamate. Intriguingly, the intracellular nitrite accumulated as high as 43.0, 42.26, 39.94 and 35.01 mg/L, when the Arthrobacter arilaitensis was incubated with Luria-Bertani medium, ammonium, nitrate and nitrite as the nitrogen source, respectively. These results confirmed that the highest concentration of intracellular nitrite was accumulated when LB was selected as the nitrogen source, followed by ammonium and nitrate, then nitrite was the least. To date, biochemical mechanism responsible for the accumulation of a high concentration of intracellular nitrite is unknown.


Assuntos
Arthrobacter/metabolismo , Nitritos/metabolismo , Nitrogênio/metabolismo , Compostos de Amônio , Nitratos , Nitrito Redutases , Oxirredutases
3.
Syst Appl Microbiol ; 42(6): 126021, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31623889

RESUMO

During long-term extra-terrestrial missions, food is limited and waste is generated. By recycling valuable nutrients from this waste via regenerative life support systems, food can be produced in space. Astronauts' urine can, for instance, be nitrified by micro-organisms into a liquid nitrate fertilizer for plant growth in space. Due to stringent conditions in space, microbial communities need to be be defined (gnotobiotic); therefore, synthetic rather than mixed microbial communities are preferred. For urine nitrification, synthetic communities face challenges, such as from salinity, ureolysis, and organics. In this study, a synthetic microbial community containing an AOB (Nitrosomonas europaea), NOB (Nitrobacter winogradskyi), and three ureolytic heterotrophs (Pseudomonas fluorescens, Acidovorax delafieldii, and Delftia acidovorans) was compiled and evaluated for these challenges. In reactor 1, salt adaptation of the ammonium-fed AOB and NOB co-culture was possible up to 45mScm-1, which resembled undiluted nitrified urine, while maintaining a 44±10mgNH4+-NL-1d-1 removal rate. In reactor 2, the nitrifiers and ureolytic heterotrophs were fed with urine and achieved a 15±6mg NO3--NL-1d-1 production rate for 1% and 10% synthetic and fresh real urine, respectively. Batch activity tests with this community using fresh real urine even reached 29±3mgNL-1d-1. Organics removal in the reactor (69±15%) should be optimized to generate a nitrate fertilizer for future space applications.


Assuntos
Reatores Biológicos/microbiologia , Microbiota , Nitrificação , Urina/química , Eliminação de Resíduos Líquidos/métodos , Amônia/metabolismo , Comamonadaceae/metabolismo , Delftia acidovorans/metabolismo , Nitritos/metabolismo , Nitrobacter/metabolismo , Nitrosomonas europaea/metabolismo , Pseudomonas fluorescens/metabolismo , Ureia/metabolismo
4.
Appl Microbiol Biotechnol ; 103(21-22): 9131-9141, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31515598

RESUMO

The biological treatment of oil refinery effluents in wastewater treatment plants (WWTPs) relies on specialized bacteria contributing to remove organic load, nitrogen, sulfur, and phosphorus compounds. Knowledge about bacterial dynamics in WWTPs and how they affect the performance of the wastewater treatment is limited, particularly in tropical countries. The bacterial communities from three compartments of an oil refinery WWTP in Uran, India, were assessed using 16S-metabarcoding, in winter and monsoon seasons, upstream (from the surge pond) and downstream the biotower (clarifier and guard pond), to understand the effects of seasonal variations in WWTP's efficiency. The organic load and ammonia levels of the treated wastewater increased by 3- and 9-fold in the monsoon time-point. A decreased abundance and diversity of 47 genera (325 OTUs) comprising ammonia and nitrite oxidizing bacteria (AOB, NOB, denitrifiers) was observed in the monsoon season downstream the biotower, whereas 23 OTUs of Sulfurospirillum, Desulfovibrio, and Bacillus, putatively performing dissimilatory nitrate reduction to ammonia (DNRA), were 3-fold more abundant in the same compartments (DNRA/denitrifiers winter ratio < 0.5 vs. monsoon ratio around 3). The total abundance of reported sulfate- and sulfite-reducing bacteria also increased 250- and 500-fold downstream the biotower, in the monsoon time-point. Bacteria performing DNRA may thus outcompete denitrification in this WWTP, limiting the biodegradation process. The alterations detected in bacterial populations involved in the removal of nitrogen and sulfur species evidenced a reduced quality of the released wastewater and may be good candidates for the following monitoring strategies and optimization of the wastewater treatment.


Assuntos
Bactérias/isolamento & purificação , Microbiota , Águas Residuárias/microbiologia , Amônia/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Desnitrificação , Índia , Nitratos/metabolismo , Nitritos/metabolismo , Petróleo/metabolismo , Filogenia , Estações do Ano
5.
Sci Total Environ ; 694: 133702, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31386948

RESUMO

Coastal wetlands accumulate enormous quantities of nitrogen due to their position at the interface between land and sea and high trapping capacity. Fortunately, they have high nitrogen (N) purifying (removal) capacity, which means that they likely play an important role in mitigating against coastal eutrophication. However studies that empirically measure the degree to which wetlands purify nitrogen and their removal pathways (e.g. denitrification, anammox, plant uptake, microbial immobilization, etc.) are rare. In this study, the N purification potential (denitrification and anammox) and enzyme activities related to denitrification in different subtropical wetlands types were conducted in nitrogen-enriched wetlands of Daya Bay, Southern China. We found the average N purification rate was 11.4 µmol N·kg-1·h-1, with denitrification accounting for 84.2%-100% of the total N2 production in the wetlands of Daya Bay. The N purification potential in the wet season, subtidal areas and mangrove forests were generally observed to be higher than that in the dry season, high and low tidal areas, barren and estuary habitats, respectively. Correspondingly, these differences were mainly driven by the temperature, Eh and NH4-N, respectively. Additionally, the nitrate reductase (Nar) and nitrite reductase (Nir) activities tended to be similar among different seasons and tidal areas, however, Nir activity in mangrove forest was 1.5-fold and 2-fold of the estuarine and barren areas, respectively. Meanwhile, Nir showed a positive correlation with denitrification rate. These results indicate that NO2-N reduction, the key control mechanism for N purification, should be the rate-limiting step of the denitrification process in Daya Bay wetlands. Notably, mangroves could improve N removal rates by 48.0% compared to other wetlands. Therefore, protecting and restoring mangrove ecosystems could be an effective way to reduce the risk of coastal eutrophication.


Assuntos
Biodegradação Ambiental , Nitritos/metabolismo , Nitrogênio/metabolismo , Áreas Alagadas , Monitoramento Ambiental , Eutrofização , Nitritos/análise
6.
Nutrients ; 11(8)2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382524

RESUMO

: Dietary nitrate (NO3-) has been reported to improve endothelial function (EF) and blood pressure (BP). However, most studies only assess large-vessel EF with little research on the microvasculature. Thus, the aim of the present pilot study is to examine NO3- supplementation on microvascular and large-vessel EF and BP. Twenty older adults (63 ± 6 years) were randomized to a beetroot juice (BRJ) or placebo (PLA) group for 28 (±7) days and attended three laboratory visitations. Across visitations, blood pressure, microvascular function and large-vessel EF were assessed by laser Doppler imaging (LDI) with iontophoresis of vasoactive substances and flow-mediated dilatation (FMD), respectively. Plasma NO3-concentrations, BP and the presence of NO3- reducing bacteria were also assessed. Plasma NO3- increased following two weeks of BRJ supplementation (p = 0.04) along with a concomitant decrease in systolic and diastolic BP of approximately -6 mmHg and -4 mmHg, respectively (p = 0.04; p = 0.01, respectively). BP remained unchanged in the PLA group. There were no significant differences in endothelium-dependent or endothelium-independent microvascular responses between groups. FMD increased by 1.5% following two weeks of BRJ (p = 0.04), with only a minimal (0.1%) change for the PLA group. In conclusion, this pilot study demonstrated that medium-term BRJ ingestion potentially improves SBP, DBP and large-vessel EF in healthy older adults. The improvements observed in the present study are likely to be greater in populations presenting with endothelial dysfunction. Thus, further prospective studies are warranted in individuals at greater risk for cardiovascular disease.


Assuntos
Beta vulgaris/química , Pressão Sanguínea/fisiologia , Endotélio Vascular/fisiologia , Sucos de Frutas e Vegetais , Microvasos/fisiologia , Nitratos/administração & dosagem , Idoso , Disponibilidade Biológica , Pressão Sanguínea/efeitos dos fármacos , Dieta , Método Duplo-Cego , Endotélio Vascular/efeitos dos fármacos , Feminino , Humanos , Masculino , Microvasos/efeitos dos fármacos , Pessoa de Meia-Idade , Nitratos/farmacocinética , Óxido Nítrico/metabolismo , Óxido Nítrico/farmacocinética , Nitritos/administração & dosagem , Nitritos/metabolismo , Projetos Piloto , Placebos , Raízes de Plantas/química
7.
Bioresour Technol ; 289: 121711, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323722

RESUMO

Transient anoxia due to the periodic anoxic/aerobic operation is beneficial for the nitrite-oxidizing bacteria (NOB) suppression. A continuous reactor of modified University of Cape Town process treating municipal wastewater was equipped with alternating anoxic/aerobic zones to maintain nitritation. Higher nitrite accumulation ratio in the oxic zones was achieved through transient anoxia and shorter aerobic actual hydraulic retention time (15 min), but it steeply deteriorated from above 95.0% to 21.0% after elevated temperature (25 °C). Batch experiments indicated that the existence of initial nitrite at the starting of aerobic phase promoted the recovery of NOB activity from transient anoxia and inhibited the activity of ammonium-oxidizing bacteria. Furthermore, a supplemental modeling further confirmed that the specific growth rates of NOB (µNOB) decreased at the anoxic phase and the recovery extent of µNOB after anoxic exposure have a positive correlation with the initial concentrations of nitrite, leading to the failure of maintaining nitritation.


Assuntos
Nitritos/metabolismo , Compostos de Amônio/metabolismo , Bactérias/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Águas Residuárias/microbiologia
8.
J Sci Food Agric ; 99(14): 6608-6619, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31347167

RESUMO

BACKGROUND: Understanding plant responses to light quantity in indoor horticultural systems is important for optimising lettuce growth and metabolism as well as energy utilisation efficiency. Light intensity and photoperiod sufficient for normal plant growth parameters might be not efficient for nitrate assimilation. Therefore, this study explored and compared the effects of different light intensities (100-500 µmol m-2 s-1 ) and photoperiods (12-24 h) on the growth and nitrate assimilation in red and green leaf lettuce (Lactuca sativa L.). RESULTS: For efficient nitrate assimilation, 300-400 µmol m-2 s-1 photosynthetic photon flux density (PPFD) and 16-18 h photoperiod is necessary for red and green lettuces. The insufficient light quantity resulted in reduced growth and remarkable increase in nitrate and nitrite contents in both cultivars. Short photoperiods, similarly to low PPFD, growth parameters, chlorophyll indices and nitrate assimilation indices showed the shortage of photosynthetic products for normal plant physiological processes. Short photoperiods had the least pronounced effect on nitrate and nitrite contents in lettuce leaves. CONCLUSION: Light intensity was superior compared to photoperiods for efficient nitrate assimilation in both lettuce cultivars. Under short photoperiods, similarly to low intensity, growth parameters, chlorophyll index and nitrate assimilation indices showed a shortage of photosynthetic products for normal physiological processes. The free amino acid concentration increased, but it was not efficiently incorporated in proteins, as their level in lettuce was lower compared to those for moderate photoperiods. © 2019 Society of Chemical Industry.


Assuntos
Alface/metabolismo , Alface/efeitos da radiação , Nitratos/metabolismo , Clorofila/análise , Clorofila/metabolismo , Cor , Alface/química , Alface/crescimento & desenvolvimento , Luz , Nitratos/análise , Nitritos/análise , Nitritos/metabolismo , Fotoperíodo , Fotossíntese , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação
9.
Food Funct ; 10(7): 4350-4360, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31276135

RESUMO

Cinnamon is known to have several physiological effects; the effects of Cinnamomum japonicum Sieb. on anti-inflammation and tight junctions were investigated in the cellular intestinal inflammation model. Cinnamon subcritical water extract (CSWE) significantly down-regulated the protein and expression levels of nitrite, prostaglandin E2 (PGE2), interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, nuclear factor kappa B (NF-κB) activity, and the phosphorylation of the factors of the NF-κB pathway. It also significantly decreased the permeability but increased the transepithelial electrical resistance (TEER) value and the protein and expression levels of tight junction proteins (i.e., zonula occludens (ZO)-1, occludin, and claudin-1). Furthermore, cinnamic acid and cinnamaldehyde, the major components of C. japonicum, inhibited the phosphorylation of the NF-κB pathway and increased the tight junction protein expression. CSWE from C. japonicum may improve intestinal health by enhancing tight junctions and inhibiting inflammation of the intestines.


Assuntos
Cinnamomum zeylanicum/química , Inflamação/tratamento farmacológico , Intestinos/efeitos dos fármacos , Extratos Vegetais/farmacologia , Junções Íntimas/efeitos dos fármacos , Animais , Células CACO-2 , Claudina-1/metabolismo , Técnicas de Cocultura , Dinoprostona , Humanos , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Camundongos , NF-kappa B/metabolismo , Nitritos/metabolismo , Ocludina/metabolismo , Permeabilidade/efeitos dos fármacos , Fosforilação , Células RAW 264.7 , Proteínas de Junções Íntimas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Água/química
10.
Cell Mol Neurobiol ; 39(8): 1187-1200, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31332667

RESUMO

Hemozoin produced by Plasmodium falciparum during malaria infection has been linked to the neurological dysfunction in cerebral malaria. In this study, we determined whether a synthetic form of hemozoin (sHZ) produces neuroinflammation and neurotoxicity in cellular models. Incubation of BV-2 microglia with sHZ (200 and 400 µg/ml) induced significant elevation in the levels of TNFα, IL-6, IL-1ß, NO/iNOS, phospho-p65, accompanied by an increase in DNA binding of NF-κB. Treatment of BV-2 microglia with sHZ increased protein levels of NLRP3 with accompanying increase in caspase-1 activity. In the presence of NF-κB inhibitor BAY11-7082 (10 µM), there was attenuation of sHZ-induced release of pro-inflammatory cytokines, NO/iNOS. In addition, increase in caspase-1/NLRP3 inflammasome activation was blocked by BAY11-7082. Pre-treatment with BAY11-7082 also reduced both phosphorylation and DNA binding of the p65 sub-unit. The NLRP3 inhibitor CRID3 (100 µM) did not prevent sHZ-induced release of TNFα and IL-6. However, production of IL-1ß, NO/iNOS as well as caspase-1/NLRP3 activity was significantly reduced in the presence of CRID3. Incubation of differentiated neural progenitor (ReNcell VM) cells with sHZ resulted in a reduction in cell viability, accompanied by significant generation of cellular ROS and increased activity of caspase-6, while sHZ-induced neurotoxicity was prevented by N-acetylcysteine and Z-VEID-FMK. Taken together, this study shows that the synthetic form of hemozoin induces neuroinflammation through the activation of NF-κB and NLRP3 inflammasome. It is also proposed that sHZ induces ROS- and caspase-6-mediated neurotoxicity. These results have thrown more light on the actions of malarial hemozoin in the neurobiology of cerebral malaria.


Assuntos
Hemeproteínas/toxicidade , Inflamação/patologia , Síndromes Neurotóxicas/patologia , Animais , Caspase 1/metabolismo , Caspase 6/metabolismo , Diferenciação Celular , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citocinas/biossíntese , DNA/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Camundongos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Nitrilos/farmacologia , Nitritos/metabolismo , Ligação Proteica/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Sulfonas/farmacologia , Fator de Transcrição RelA/metabolismo
11.
Bioresour Technol ; 291: 121854, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31357041

RESUMO

Two strains, Enterobacter sp. Z1 and Klebsiella sp. Z2, were exhibited great capacities for heterotrophic nitrification-aerobic denitrification (HNAD) and intracellular phosphate accumulation. Strikingly, the co-cultured strains enhanced the removal efficiency of total nitrogen and phosphate, with removal efficiencies of ammonia, nitrate, nitrite and soluble phosphate of 99.64%, 99.85%, 96.94% and 66.7% respectively. Furthermore, high removal efficiencies from wastewaters with high concentrations of ammonia (over 1000 mg/L) were achieved by inoculation with the co-strains, which left residual ammonia of less than 1 mg/L within 10 h. To elucidate the mechanism of HNAD in co-strains, quantitative PCR was carried out to examine the expression levels of hydroxylamine oxidase (Hao), nitrate reductase (NapA and NarG), nitrite reductase (NirS) and polyphosphate kinase (Ppk), and the results showed that the napA2, narG and ppk genes in the strains were significantly upregulated under the co-cultured conditions and provided an explanation for the nitrogen and phosphate removal.


Assuntos
Enterobacter/metabolismo , Klebsiella/metabolismo , Nitrogênio/metabolismo , Fosfatos/metabolismo , Amônia/metabolismo , Desnitrificação , Processos Heterotróficos , Nitrato Redutase/metabolismo , Nitratos/metabolismo , Nitrificação , Nitrito Redutases/metabolismo , Nitritos/metabolismo , Oxirredutases/metabolismo , Águas Residuárias
12.
Int J Syst Evol Microbiol ; 69(8): 2471-2476, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31180314

RESUMO

A nitrite-tolerant denitrifying bacterium, strain GL14T, was isolated from the nitrification/denitrification bioreactor in our laboratory. Strain GL14T was Gram-stain-negative, rod-shaped, non-spore-forming, facultatively anaerobic and motile by means of a single polar flagellum. Phylogenetic analyses based on 16S rRNA gene sequences indicated that it was assigned to the genus Pseudomonas with highest 16S rRNA gene sequence similarity (98.77 %) to Pseudomonas xanthomarina DSM 18231T and Pseudomonassongnenensis NEAU-ST5-5T, followed by Pseudomonasstutzeri ATCC 17588T (98.42 %), Pseudomonaskunmingensis HL22-2T (98.29 %) and Pseudomonaszhaodongensis NEAU-ST5-21T (98.22 %). Phylogenetic analysis based on both concatenated sequences of the 16S rRNA gene and two housekeeping genes (gyrB and rpoD) and genome sequences further clarified the intrageneric phylogenetic position of strain GL14T. The DNA G+C content of GL14T was 63.1 mol%. The results of digital DNA-DNA hybridization (highest 24.2 % of DNA-DNA relatedness) based on the Genome-to-Genome Distance Calculator and average nucleotide identity analyses (highest 80.23 %) confirmed that the strain was distinctly delineated from known species of the genus Pseudomonas. The major fatty acids were summed feature 8 (C18 : 1ω7c/C18 : 1ω6c), C16 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), C17 : 0cyclo and C12 : 0. The respiratory quinone was ubiquinone Q-9. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Based on the phylogenetic, genomic, phenotypic and chemotaxonomic analyses, it was concluded that strain GL14T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas nitrititolerans sp. nov. is proposed. The type strain is GL14T (=CGMCC 1.13874T=NBRC 113853T).


Assuntos
Reatores Biológicos/microbiologia , Nitritos/metabolismo , Filogenia , Pseudomonas/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Desnitrificação , Ácidos Graxos/química , Genes Bacterianos , Nitrificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
13.
Arch Virol ; 164(9): 2231-2241, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31177351

RESUMO

Viral persistence alters cellular antiviral activities. Nitric oxide (NO), a highly reactive free radical and a potent antiviral molecule, can inhibit replication of RNA and DNA viruses, but its production and effect during viral persistence are largely unknown. NO synthesis is stimulated in epithelial cells during acute infection with respiratory syncytial virus (RSV) and interferes with viral replication. In this study, we compared the levels of production of NO and expression of its regulatory enzymes, inducible nitric oxide synthase (NOS II) and arginase 1 (Arg-1), during acute and persistent RSV infection in a macrophage cell line to investigate their role in the control and maintenance of viral infection. We observed that NO and NOS II mRNA were induced at higher levels in acutely infected macrophages than in persistently infected macrophages, while the kinetics of NOS II protein expression were similar in both types of infected cultures, except that its disappearance was delayed during acute infection. Thus, NOS II was inducible and expressed at high levels during persistent infection, but production of NO was low relative to acute infection. This was not associated with a lack of enzymatic activity but instead was due to constitutive expression of the Arg-1 enzyme at the mRNA and protein levels, suggesting that arginase restricts availability of L-arginine as a substrate for NOS II to synthesize NO. This hypothesis was supported by showing that arginase enzymatic activity was inhibited in persistently RSV-infected cells by Nω-hydroxy-nor-L-arginine, increasing L-arginine availability in conditioned medium and producing increased levels of nitrites, concurrently with a significant reduction in virus genome replication, implying that Arg-1 overexpression contributes to the maintenance of the RSV genome in the host in persistent infection.


Assuntos
Arginase/metabolismo , Óxido Nítrico/metabolismo , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/fisiologia , Arginase/genética , Arginina/metabolismo , Regulação para Baixo , Humanos , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Nitritos/metabolismo , Infecções por Vírus Respiratório Sincicial/enzimologia , Infecções por Vírus Respiratório Sincicial/genética , Vírus Sincicial Respiratório Humano/genética , Replicação Viral
14.
Molecules ; 24(11)2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31185705

RESUMO

Parkinson's disease, a chronic, age related neurodegenerative disorder, is characterized by a progressive loss of nigrostriatal dopaminergic neurons. Several studies have proven that the activation of glial cells, presence of alpha-synuclein aggregates, and oxidative stress, fuels neurodegeneration, and currently there is no definitive treatment for PD. In this study, a rotenone-induced rat model of PD was used to understand the neuroprotective potential of Lycopodium (Lyc), a commonly-used potent herbal medicine. Immunohistochemcial data showed that rotenone injections significantly increased the loss of dopaminergic neurons in the substantia nigra, and decreased the striatal expression of tyrosine hydroxylase. Further, rotenone administration activated microglia and astroglia, which in turn upregulated the expression of α-synuclein, pro-inflammatory, and oxidative stress factors, resulting in PD pathology. However, rotenone-injected rats that were orally treated with lycopodium (50 mg/kg) were protected against dopaminergic neuronal loss by diminishing the expression of matrix metalloproteinase-3 (MMP-3) and MMP-9, as well as reduced activation of microglia and astrocytes. This neuroprotective mechanism not only involves reduction in pro-inflammatory response and α-synuclein expression, but also synergistically enhanced antioxidant defense system by virtue of the drug's multimodal action. These findings suggest that Lyc has the potential to be further developed as a therapeutic candidate for PD.


Assuntos
Encéfalo/patologia , Neurônios Dopaminérgicos/patologia , Inflamação/patologia , Lycopodium/química , Estresse Oxidativo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/patologia , Extratos Vegetais/uso terapêutico , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Glutationa/metabolismo , Mediadores da Inflamação/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Metaloproteinases da Matriz/metabolismo , Microglia/efeitos dos fármacos , Microglia/metabolismo , Degeneração Neural/patologia , Neuroproteção/efeitos dos fármacos , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Nitritos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Ratos Wistar , Rotenona , Superóxido Dismutase/metabolismo , alfa-Sinucleína/metabolismo
15.
J Agric Food Chem ; 67(26): 7205-7222, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31244197

RESUMO

Nitrate and nitrite ions are used as food additives to inhibit the growth of microorganisms in cured and processed meats. Vegetables contain significant quantities of nitrate and nitrite. Actually, the vast majority of consumed nitrate and nitrite comes from natural vegetables and fruits rather than food additives. For years, the cancer risks of these two ions have been discussed, since they potentially convert into the carcinogenic nitrosamines. However, recently, these two ions have been considered essential nutrients which promote nitric oxide production and consequently help cardiovascular health. It seems that the role of these two ions in our diet is important now from a different point of view. In this review, the nitrate and nitrite contents of food products from different countries are displayed globally in order to reinterpret the risks/benefits of our consumption quotations. This review article is based on Science Citation Index (SCI) articles reported between 2008 and 2018.


Assuntos
Nitratos/análise , Nitritos/análise , Animais , Aditivos Alimentares/análise , Aditivos Alimentares/metabolismo , Humanos , Carne/análise , Nitratos/metabolismo , Nitritos/metabolismo , Medição de Risco , Verduras/química
16.
Int J Nanomedicine ; 14: 4145-4155, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31239673

RESUMO

Background: There is emerging evidence which suggests that cellular ROS including nitric oxide (NO) are important mediators for inflammation and osteoarthritis (OA). Water-soluble polyhydroxylated fullerene C60 (fullerol) nanoparticle has been demonstrated to have an outstanding ability to scavenge ROS. Purpose: The objective of this study is to assess the effects of fullerol on inflammation and OA by in vitro and in vivo studies. Methods: For in vitro experiments, primary mouse peritoneal macrophages and a macrophage cell line RAW264.7 were stimulated to inflammatory phenotypes by lipopolysaccharide (LPS) in the presence of fullerol. For the animal study, OA model was created by intra-articular injection of monoiodoacetate into the knee joints of rats and fullerol was intravenously injected immediately after OA induction. Results: NO production and pro-inflammatory gene expression induced by LPS was significantly diminished by fullerol in both macrophage cell types. Meanwhile, fullerol could remarkably reduce phosphorylation of p38 mitogen-activated protein kinase, and protein level of transcription factors nuclear factor-kappaB and forkhead box transcription factor 1 within the nucleus. The animal study delineated that systematic administration of fullerol prevented OA, inhibiting inflammation of synovial membranes and the damage toward the cartilage chondrocytes in the OA joints. Conclusion: Antioxidative fullerol may have a potential therapeutic application for OA.


Assuntos
Antioxidantes/farmacologia , Fulerenos/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Nanopartículas/química , Osteoartrite/patologia , Animais , Células Cultivadas , Feminino , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Articulações/efeitos dos fármacos , Articulações/patologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/patologia , Masculino , Camundongos , Modelos Biológicos , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Nitritos/metabolismo , Osteoartrite/tratamento farmacológico , Células RAW 264.7 , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/metabolismo
17.
BMC Evol Biol ; 19(1): 129, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31221104

RESUMO

BACKGROUND: Substrate cross-feeding occurs when one organism partially consumes a primary substrate into one or more metabolites while other organisms then consume the metabolites. While pervasive within microbial communities, our knowledge about the effects of substrate cross-feeding on microbial evolution remains limited. To address this knowledge gap, we experimentally evolved isogenic nitrite (NO2-) cross-feeding microbial strains together for 700 generations, identified genetic changes that were acquired over the evolution experiment, and compared the results with an isogenic completely denitrifying strain that was evolved alone for 700 generations. We further investigated how the magnitude of interdependence between the nitrite cross-feeding strains affects the main outcomes. Our main objective was to quantify how substrate cross-feeding and the magnitude of interdependence affect the speed and trajectory of molecular evolution. RESULTS: We found that each nitrite (NO2-) cross-feeding strain acquired fewer genetic changes than did the completely denitrifying strain. In contrast, pairs of nitrite cross-feeding strains together acquired more genetic changes than did the completely denitrifying strain. Moreover, nitrite cross-feeding promoted population diversification, as pairs of nitrite cross-feeding strains acquired a more varied set of genetic changes than did the completely denitrifying strain. These outcomes likely occurred because nitrite cross-feeding enabled the co-existence of two distinct microbial strains, thus increasing the amount of genetic variation for selection to act upon. Finally, the nitrite cross-feeding strains acquired different types of genetic changes than did the completely denitrifying strain, indicating that nitrite cross-feeding modulates the trajectory of molecular evolution. CONCLUSIONS: Our results demonstrate that substrate cross-feeding can affect both the speed and trajectory of molecular evolution within microbial populations. Substrate cross-feeding can therefore have potentially important effects on the life histories of microorganisms.


Assuntos
Evolução Molecular , Microbiota , Nitritos/metabolismo , Bactérias/metabolismo , Desnitrificação , Pseudomonas stutzeri/metabolismo
18.
Appl Microbiol Biotechnol ; 103(15): 6023-6039, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31209526

RESUMO

Biological denitrification process in mainstream wastewater treatment often needs dosing supplemental electrons, consequently adding a remarkable operating cost. Organic carbon compounds are nowadays the most intensively used electron sources in full-scale wastewater treatment, corresponding with the well-understood carbon-nitrogen biogeochemistry for heterotrophic denitrification process. In the twenty-first century, the low-carbon technology is on calling to reduce the carbon footprint and relieve climate changing threatens. Autotrophic denitrification is highly recommended for mainstream wastewater treatment. The reduced-sulphur compounds (such as sulphide, elemental sulphur, and thiosulphate) could be utilised as electron donors, to drive sulphur cycle reactions to reduce nitrate and nitrite to dinitrogen gas. Based on the literature review and our own research experiences, this paper presents our perspectives on sulphur-driven autotrophic denitrification. It particularly focuses on the functional enzymes, sulphur bioreactors, and influential operating factors. Overall, this paper provides new insights on sulphur-nitrogen biogeochemistry and application as a low-carbon technology for nitrogen removal during municipal wastewater treatment.


Assuntos
Desnitrificação , Nitrogênio/metabolismo , Compostos de Enxofre/metabolismo , Águas Residuárias/microbiologia , Purificação da Água/métodos , Processos Autotróficos , Nitratos/metabolismo , Nitritos/metabolismo
19.
Food Chem Toxicol ; 131: 110594, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31226431

RESUMO

The phytochemical composition and the antioxidant and anti-inflammatory activities of a mixture of 23 plants, named Horchata, traditionally consumed in Ecuador, have been evaluated. The study was carried out using the hydroalcoholic extract (HHext) and infusion (IHext) of the horchata plant mixture. It was verified that thermal treatment affected the contents of vitamin C and carotenoids, but hardly those of polyphenols, which would be the main bioactive compounds in the infusion, the common form of preparation of horchata for consumption. Among phenolic compounds, caffeoylquinic acids, flavones and flavonols (mostly quercetin glycosides) were prominent. Both HHext and IHext extracts managed to protect RAW 264.7 macrophages against LPS-induced cytotoxic damage, increasing the levels of endogenous antioxidant enzymes and modulating the production of pro-inflammatory and anti-inflammatory cytokines. Greater protective effects were obtained for HHext compared to IHext, which was in agreement with its higher content of phenolic compounds favoured by a more efficient extraction in the hydroalcoholic medium. Nonetheless, the infusion still maintained a significant antioxidant and anti-inflammatory activity, which would support the protective effects on health traditionally attributed to its consumption by the population.


Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Extratos Vegetais/farmacologia , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Ácido Ascórbico/análise , Biomarcadores/metabolismo , Carotenoides/análise , Equador , Inflamação/induzido quimicamente , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos , Camundongos , Nitritos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Plantas Medicinais/química , Polifenóis/análise , Células RAW 264.7 , Temperatura Ambiente , Fator de Necrose Tumoral alfa/metabolismo
20.
Chemosphere ; 234: 855-863, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31252357

RESUMO

Methane oxidation coupled to selenate reduction has been suggested as a promising technology to bio-remediate selenium contaminated environments. However, the effect of dissolved oxygen (DO) on this process remained unclear. Here, we investigate the feasibility of selenate removal at two distinct DO concentrations. A membrane biofilm reactor (MBfR) was initially fed with ∼5 mg Se/L and then lowered to ∼1 mg Se/L of selenate, under anoxic condition containing ∼0.2 mg/L of influent DO. Selenate removal reached approximately 90% without selenite accumulation after one-month operation. Then 6-7 mg/L of DO was introduced and showed no apparent effect on selenate reduction in the subsequent operation. Electron microscopy suggested elevated oxygen exposure did not affect microbial shapes. 16S rDNA sequencing showed the aerobic methanotroph Methylocystis increased, while possible selenate reducers, Ignavibacterium and Bradyrhizobium, maintained stable after oxygen boost. Gene analysis indicated that nitrate/nitrite reductases positively correlated with selenate removal flux and were not remarkably affected by oxygen addition. Reversely, enzymes related with aerobic methane oxidation were obviously improved. This study provides a potential technology for selenate removal from oxygenated environments in a methane-based MBfR.


Assuntos
Metano/química , Oxigênio/farmacologia , Ácido Selênico/química , Bactérias/enzimologia , Bactérias/isolamento & purificação , Biofilmes , Reatores Biológicos/microbiologia , Membranas Artificiais , Nitratos/metabolismo , Nitritos/metabolismo , Oxirredução , Ácido Selênico/isolamento & purificação
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