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2.
J Sci Food Agric ; 102(1): 147-155, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34057213

RESUMO

BACKGROUND: Bacterial community successions were surveyed during the processing stages of sugar production using high-throughput sequencing methods. Furthermore, the correlation between bacterial community and nitrate/nitrite content in beet sugar processing were investigated. RESULTS: In an analysis of the V3-V4 region of the 16S rDNA gene, 254 122 effective sequences were obtained from samples, which included sugar beet, cossettes, diffusion juice, second-phase diffusion juice, light juice and thick juice. The results showed that dominant genera included Pantoea, Pseudomonas, Leuconostoc and Burkholderia. Moreover, significant changes in bacterial communities were observed in samples. Regarding the relevant nitrogen metabolic potential, this study revealed communities with the ability for nitrate and nitrite metabolism. Furthermore, a shaking experiment involving diffusion juice and second-phase diffusion juice was performed, and results showed that the nitrate level declined 73% and 98% in 36 h, respectively. These results suggested that the bacterial communities contribute to nitrate and nitrite transformation. CONCLUSION: This study illustrated that the bacterial communities and their specific effects on the formation of nitrate and nitrite during beet sugar processing. The results presented the basic concept involving the nitrate- and nitrite-forming pathways directly related to the mechanism of bacterial community growth. This study could facilitate an understanding of the correlation between nitrite content and microorganisms to guide beet sugar manufacturers regarding the control of nitrite and nitrate content. © 2021 Society of Chemical Industry.


Assuntos
Bactérias/metabolismo , Beta vulgaris/química , Nitratos/análise , Nitritos/análise , Tubérculos/microbiologia , Açúcares/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Beta vulgaris/microbiologia , Biotransformação , Manipulação de Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Nitratos/metabolismo , Nitritos/metabolismo , Tubérculos/química , Açúcares/química
3.
Nutrients ; 13(10)2021 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-34684537

RESUMO

Anti-inflammatory agents that are safer and more effective than the currently used non-steroidal anti-inflammatory drugs are urgently needed. The dicaffeoylquinic acid (diCQA) isomer 4,5-diCQA exhibits antioxidant activity and various other health-promoting benefits; however, its anti-inflammatory properties require further investigation. This study was conducted to evaluate the anti-inflammatory properties of 4,5-diCQA in vitro and in vivo using RAW264.7 cells and a carrageenan-induced inflammation model, respectively. In RAW264.7 cells, 4,5-diCQA pretreatment significantly inhibited lipopolysaccharide-induced expression of nitric oxide, prostaglandin E2, nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α, interleukin-1ß, and interleukin-6, without inducing cytotoxicity. The inhibitory effects of 4,5-diCQA were mediated by the suppression of nuclear factor-κB nuclear translocation and mitogen-activated protein kinase (MAPK) phosphorylation. Oral administration of 4,5-diCQA at doses of 5, 10, and 20 mg/kg of the body weight suppressed carrageenan-induced edema and the expression of nitric oxide synthase, cyclooxygenase-2, and tumor necrosis factor-α in a dose-dependent manner. Collectively, our results suggest that 4,5-diCQA exerts anti-inflammatory effects by suppressing activation of the nuclear factor-κB and MAPK pathways in vitro and reducing carrageenan-induced edema in vivo. Therefore, 4,5-diCQA shows potential as a natural alternative to non-steroidal anti-inflammatory drugs.


Assuntos
Anti-Inflamatórios/uso terapêutico , Inflamação/tratamento farmacológico , Ácido Quínico/análogos & derivados , Animais , Anti-Inflamatórios/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Dinoprostona/metabolismo , Modelos Animais de Doenças , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Nitritos/metabolismo , Fosforilação/efeitos dos fármacos , Ácido Quínico/química , Ácido Quínico/farmacologia , Ácido Quínico/uso terapêutico , Células RAW 264.7 , Ratos Sprague-Dawley
4.
Int J Mol Sci ; 22(18)2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34576085

RESUMO

Bitter-taste receptors (T2Rs) have emerged as key players in host-pathogen interactions and important modulators of oral innate immunity. Previously, we reported that T2R14 is expressed in gingival epithelial cells (GECs) and interacts with competence stimulating peptides (CSPs) secreted by the cariogenic Streptococcus mutans. The underlying mechanisms of the innate immune responses and physiological effects of T2R14 on Gram-positive bacteria are not well characterized. In this study, we examined the role of T2R14 in internalization and growth inhibitory effects on Gram-positive bacteria, namely Staphylococcus aureus and S. mutans. We utilized CRISPR-Cas9 T2R14 knockdown (KD) GECs as the study model to address these key physiological mechanisms. Our data reveal that the internalization of S. aureus is significantly decreased, while the internalization of S. mutans remains unaffected upon knockdown of T2R14 in GECs. Surprisingly, GECs primed with S. mutans CSP-1 resulted in an inhibition of growth for S. aureus, but not for S. mutans. The GECs infected with S. aureus induced T2R14-dependent human ß-defensin-2 (hBD-2) secretion; however, S. mutans-infected GECs did not induce hBD-2 secretion, but induced T2R14 dependent IL-8 secretion. Interestingly, our results show that T2R14 KD affects the cytoskeletal reorganization in GECs, thereby inhibiting S. aureus internalization. Our study highlights the distinct mechanisms and a direct role of T2R14 in influencing physiological responses to Gram-positive bacteria in the oral cavity.


Assuntos
Endocitose , Células Epiteliais/metabolismo , Gengiva/citologia , Bactérias Gram-Positivas/metabolismo , Viabilidade Microbiana , Receptores Acoplados a Proteínas G/metabolismo , Paladar , Actinas/metabolismo , Linhagem Celular , Células Epiteliais/ultraestrutura , Humanos , Interleucina-8/metabolismo , Modelos Biológicos , Nitratos/metabolismo , Nitritos/metabolismo , Staphylococcus aureus/metabolismo , Streptococcus mutans/metabolismo , beta-Defensinas/metabolismo , Quinases Ativadas por p21/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo
5.
Sci Rep ; 11(1): 17276, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34446760

RESUMO

Denitrification is a respiratory process by which nitrate is reduced to dinitrogen. Incomplete denitrification results in the emission of the greenhouse gas nitrous oxide and this is potentiated in acidic soils, which display reduced denitrification rates and high N2O/N2 ratios compared to alkaline soils. In this work, impact of pH on the proteome of the soil denitrifying bacterium Paracoccus denitrificans PD1222 was analysed with nitrate as sole energy and nitrogen source under anaerobic conditions at pH ranging from 6.5 to 7.5. Quantitative proteomic analysis revealed that the highest difference in protein representation was observed when the proteome at pH 6.5 was compared to the reference proteome at pH 7.2. However, this difference in the extracellular pH was not enough to produce modification of intracellular pH, which was maintained at 6.5 ± 0.1. The biosynthetic pathways of several cofactors relevant for denitrification and nitrogen assimilation like cobalamin, riboflavin, molybdopterin and nicotinamide were negatively affected at pH 6.5. In addition, peptide representation of reductases involved in nitrate assimilation and denitrification were reduced at pH 6.5. Data highlight the strong negative impact of pH on NosZ synthesis and intracellular copper content, thus impairing active NosZ assembly and, in turn, leading to elevated nitrous oxide emissions.


Assuntos
Proteínas de Bactérias/metabolismo , Paracoccus denitrificans/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Microbiologia do Solo , Proteínas de Bactérias/genética , Desnitrificação , Regulação Bacteriana da Expressão Gênica , Concentração de Íons de Hidrogênio , Nitratos/metabolismo , Nitritos/metabolismo , Nitrogênio/metabolismo , Óxido Nitroso/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Paracoccus denitrificans/genética , Proteoma/genética , Solo/química
6.
J Nippon Med Sch ; 88(3): 189-193, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34193742

RESUMO

BACKGROUND: Oxidative stress is thought to be closely related to epileptogenesis. We have previously reported that nitric oxide (NO) levels are higher in epilepsy-prone EL mice between the ages of 3 and 8 weeks than in control mice. However, NO is divided into two fractions, nitrite (NO2) and nitrate (NO3), which appear to play different roles in epileptogenesis. METHODS: NO2 and NO3 levels were measured, in EL mice and the control mice, in the parietal cortex, which is thought to be the primary epileptogenetic center in EL mice, and measured in the hippocampus, which is thought to be the secondary center. RESULTS: NO3 levels in the hippocampus and parietal cortex of the immature EL mice (3 to 8 weeks of age) were significantly higher than those in the control mice; NO2 levels were significantly higher in the EL mice throughout the study period. The NO3 levels were significantly higher than the NO2 levels in the immature EL mice, but after the onset of ictogenesis at 10 weeks of age, the relative levels of the two fractions reversed. CONCLUSION: The reversal of the NO fraction distribution at the onset of seizures that we observed may be related to the developmental process of seizure susceptibility in the neural network of EL mice.


Assuntos
Modelos Animais de Doenças , Epilepsia/etiologia , Epilepsia/metabolismo , Nitratos/metabolismo , Óxido Nítrico/metabolismo , Nitritos/metabolismo , Estresse Oxidativo/fisiologia , Animais , Hipocampo/metabolismo , Camundongos Endogâmicos , Rede Nervosa , Nitratos/fisiologia , Óxido Nítrico/fisiologia , Nitritos/farmacologia , Lobo Parietal/lesões , Lobo Parietal/metabolismo
7.
Nat Microbiol ; 6(9): 1129-1139, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34267357

RESUMO

Nitrate is an abundant nutrient and electron acceptor throughout Earth's biosphere. Virtually all nitrate in nature is produced by the oxidation of nitrite by the nitrite oxidoreductase (NXR) multiprotein complex. NXR is a crucial enzyme in the global biological nitrogen cycle, and is found in nitrite-oxidizing bacteria (including comammox organisms), which generate the bulk of the nitrate in the environment, and in anaerobic ammonium-oxidizing (anammox) bacteria which produce half of the dinitrogen gas in our atmosphere. However, despite its central role in biology and decades of intense study, no structural information on NXR is available. Here, we present a structural and biochemical analysis of the NXR from the anammox bacterium Kuenenia stuttgartiensis, integrating X-ray crystallography, cryo-electron tomography, helical reconstruction cryo-electron microscopy, interaction and reconstitution studies and enzyme kinetics. We find that NXR catalyses both nitrite oxidation and nitrate reduction, and show that in the cell, NXR is arranged in tubules several hundred nanometres long. We reveal the tubule architecture and show that tubule formation is induced by a previously unidentified, haem-containing subunit, NXR-T. The results also reveal unexpected features in the active site of the enzyme, an unusual cofactor coordination in the protein's electron transport chain, and elucidate the electron transfer pathways within the complex.


Assuntos
Bactérias/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Oxirredutases/química , Oxirredutases/metabolismo , Bactérias/química , Bactérias/genética , Proteínas de Bactérias/genética , Domínio Catalítico , Microscopia Crioeletrônica , Cristalografia por Raios X , Cinética , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Nitratos/metabolismo , Nitritos/metabolismo , Oxirredução , Oxirredutases/genética
8.
Biochem Biophys Res Commun ; 568: 136-142, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34214877

RESUMO

Vibrio species are prevalent in the aquatic environments and can infect humans and aquatic organisms. Vibrio parahaemolyticus counteracts ß-lactam antibiotics and enhances virulence using a regulation mechanism mediated by a two-component regulatory system (TCS) consisting of the VbrK histidine kinase and the VbrR response regulator. The periplasmic sensor domain of VbrK (VbrKSD) detects ß-lactam antibiotics or undergoes S-nitrosylation in response to host nitrites. Although V. parahaemolyticus VbrKSD (vpVbrKSD) has recently been characterized through structural studies, it is unclear whether its structural features that are indispensable for biological functions are conserved in other VbrK orthologs. To structurally define the functionally critical regions of VbrK and address the structural dynamics of VbrK, we determined the crystal structures of Vibrio rotiferianus VbrKSD (vrVbrKSD) in two crystal forms and performed a comparative analysis of diverse VbrK structures. vrVbrKSD folds into a curved rod-shaped two-domain structure as observed in vpVbrKSD. The membrane-distal end of the vrVbrKSD structure, including the α3 helix and its neighboring loops, harbors both S-nitrosylation and antibiotic-sensing sites and displays high structural flexibility and diversity. Noticeably, the distal end is partially stabilized by a disulfide bond, which is formed by the cysteine residue that is S-nitrosylated in response to nitrite. Therefore, the distal end of VbrKSD plays a key role in initiating the VbrK-VbrR TCS pathway activation, and it is involved in the nitrosylation-mediated regulation of the structural dynamics of VbrK.


Assuntos
Proteínas de Bactérias/química , Histidina Quinase/química , Vibrio/química , Antibacterianos/metabolismo , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X , Histidina Quinase/metabolismo , Modelos Moleculares , Nitritos/metabolismo , Domínios Proteicos , Vibrio/metabolismo
9.
Sci Rep ; 11(1): 12709, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34135407

RESUMO

Congenital toxoplasmosis is represented by the transplacental passage of Toxoplasma gondii from the mother to the fetus. Our studies demonstrated that T. gondii developed mechanisms to evade of the host immune response, such as cyclooxygenase (COX)-2 and prostaglandin E2 (PGE2) induction, and these mediators can be produced/stored in lipid droplets (LDs). The aim of this study was to evaluate the role of COX-2 and LDs during T. gondii infection in human trophoblast cells and villous explants. Our data demonstrated that COX-2 inhibitors decreased T. gondii replication in trophoblast cells and villous. In BeWo cells, the COX-2 inhibitors induced an increase of pro-inflammatory cytokines (IL-6 and MIF), and a decrease in anti-inflammatory cytokines (IL-4 and IL-10). In HTR-8/SVneo cells, the COX-2 inhibitors induced an increase of IL-6 and nitrite and decreased IL-4 and TGF-ß1. In villous explants, the COX-2 inhibitors increased MIF and decreased TNF-α and IL-10. Furthermore, T. gondii induced an increase in LDs in BeWo and HTR-8/SVneo, but COX-2 inhibitors reduced LDs in both cells type. We highlighted that COX-2 is a key factor to T. gondii proliferation in human trophoblast cells, since its inhibition induced a pro-inflammatory response capable of controlling parasitism and leading to a decrease in the availability of LDs, which are essentials for parasite growth.


Assuntos
Vilosidades Coriônicas/parasitologia , Ciclo-Oxigenase 2/metabolismo , Gotículas Lipídicas/metabolismo , Toxoplasma/crescimento & desenvolvimento , Trofoblastos/parasitologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Vilosidades Coriônicas/imunologia , Vilosidades Coriônicas/metabolismo , Inibidores de Ciclo-Oxigenase 2/farmacologia , Proteínas da Matriz Extracelular/metabolismo , Interações Hospedeiro-Parasita , Humanos , Interleucinas/metabolismo , Fatores Inibidores da Migração de Macrófagos/metabolismo , Nitritos/metabolismo , Toxoplasma/imunologia , Fator de Crescimento Transformador beta/metabolismo , Trofoblastos/imunologia , Trofoblastos/metabolismo
10.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072989

RESUMO

Under anaerobic conditions, bacteria may utilize nitrates and nitrites as electron acceptors. Sensitivity to nitrous compounds is achieved via several mechanisms, some of which rely on sensor histidine kinases (HKs). The best studied nitrate- and nitrite-sensing HKs (NSHKs) are NarQ and NarX from Escherichia coli. Here, we review the function of NSHKs, analyze their natural diversity, and describe the available structural information. In particular, we show that around 6000 different NSHK sequences forming several distinct clusters may now be found in genomic databases, comprising mostly the genes from Beta- and Gammaproteobacteria as well as from Bacteroidetes and Chloroflexi, including those from anaerobic ammonia oxidation (annamox) communities. We show that the architecture of NSHKs is mostly conserved, although proteins from Bacteroidetes lack the HAMP and GAF-like domains yet sometimes have PAS. We reconcile the variation of NSHK sequences with atomistic models and pinpoint the structural elements important for signal transduction from the sensor domain to the catalytic module over the transmembrane and cytoplasmic regions spanning more than 200 Å.


Assuntos
Bactérias/enzimologia , Proteínas de Bactérias , Histidina Quinase , Proteínas de Membrana , Nitratos/metabolismo , Nitritos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Histidina Quinase/química , Histidina Quinase/classificação , Histidina Quinase/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Domínios Proteicos
11.
Int J Mol Sci ; 22(9)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33947005

RESUMO

Beneficial metabolic effects of inorganic nitrate (NO3-) and nitrite (NO2-) in type 2 diabetes mellitus (T2DM) have been documented in animal experiments; however, this is not the case for humans. Although it has remained an open question, the redox environment affecting the conversion of NO3- to NO2- and then to NO is suggested as a potential reason for this lost-in-translation. Ascorbic acid (AA) has a critical role in the gastric conversion of NO2- to NO following ingestion of NO3-. In contrast to AA-synthesizing species like rats, the lack of ability to synthesize AA and a lower AA body pool and plasma concentrations may partly explain why humans with T2DM do not benefit from NO3-/NO2- supplementation. Rats also have higher AA concentrations in their stomach tissue and gastric juice that can significantly potentiate gastric NO2--to-NO conversion. Here, we hypothesized that the lack of beneficial metabolic effects of inorganic NO3- in patients with T2DM may be at least in part attributed to species differences in AA metabolism and also abnormal metabolism of AA in patients with T2DM. If this hypothesis is proved to be correct, then patients with T2DM may need supplementation of AA to attain the beneficial metabolic effects of inorganic NO3- therapy.


Assuntos
Ácido Ascórbico/uso terapêutico , Diabetes Mellitus Tipo 2/metabolismo , Nitratos/farmacocinética , Oxirredutases do Álcool/deficiência , Animais , Arginina/metabolismo , Ácido Ascórbico/metabolismo , Ácido Ascórbico/farmacologia , Deficiência de Ácido Ascórbico/complicações , Deficiência de Ácido Ascórbico/tratamento farmacológico , Ensaios Clínicos como Assunto , Diabetes Mellitus Tipo 2/complicações , Dieta , Suco Gástrico/metabolismo , Mucosa Gástrica/metabolismo , Glucose/metabolismo , Cobaias , Homeostase , Humanos , Insulina/metabolismo , Camundongos , Modelos Animais , Nitratos/administração & dosagem , Nitratos/metabolismo , Nitratos/uso terapêutico , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Nitritos/metabolismo , Nitritos/farmacocinética , Necessidades Nutricionais , Oxirredução , Ratos , Especificidade da Espécie
12.
Food Chem ; 361: 129997, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34029911

RESUMO

The contribution of free amino acids and thiamine to the production of potent meat aroma compounds in nitrite-reduced, dry-fermented sausages inoculated with a D. hansenii strain was the objective of this study. For this, three different sausage formulations were manufactured; a control and two formulations reduced by half in nitrate and nitrite and one of them inoculated with D. hansenii. Free amino acids, thiamine content and savoury volatile compounds were analysed. Eleven savoury volatile compounds were quantitated. Among them, the most potent compounds above their odour thresholds were 2-methyl-3-furanthiol, 2-acetyl-1-pyrroline, methional, dimethyl trisulfide and methyl-2-methyl-3-furyl disulfide. Their generation was affected by D. hansenii inoculation as shown by the decrease in methional and methyl 2-methyl-3-furyl disulfide content, and the increase of methionol. Nitrate and nitrite reduction did not significantly affect amino acid and thiamine contents.


Assuntos
Aminoácidos/análise , Debaryomyces , Produtos da Carne/análise , Odorantes/análise , Aldeídos/análise , Fermentação , Produtos da Carne/microbiologia , Nitratos/metabolismo , Nitritos/metabolismo , Tiamina/análise , Fermento Seco
13.
Biomolecules ; 11(4)2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33806006

RESUMO

A madecassoside-rich fraction obtained from the industrial purification of Centella asiatica leaves afforded a new triterpene glycoside, named isomadecassoside (4), characterized by an ursane-type skeleton and migration of the double bond at Δ20(21) in ring E. The structure of isomadecassoside was established by means of HR-ESIMS and detailed analysis of 1D and 2D NMR spectra, which allowed a complete NMR assignment. Studies on isolated J774A.1 macrophages stimulated by LPS revealed that isomadecassoside (4) inhibited nitrite production at non-cytotoxic concentrations, thus indicating an anti-inflammatory effect similar to that of madecassoside.


Assuntos
Centella/química , Glicosídeos/farmacologia , Macrófagos/efeitos dos fármacos , Nitritos/metabolismo , Triterpenos/química , Sobrevivência Celular/efeitos dos fármacos , Centella/metabolismo , Glicosídeos/química , Glicosídeos/isolamento & purificação , Humanos , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Macrófagos/metabolismo , Espectroscopia de Ressonância Magnética , Conformação Molecular , Extratos Vegetais/química , Folhas de Planta/metabolismo
14.
Appl Environ Microbiol ; 87(12): e0009221, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-33837020

RESUMO

Land use types with different disturbance gradients show many variations in soil properties, but the effects of different land use types on soil nitrifying communities and their ecological implications remain poorly understood. Using 13CO2-DNA-based stable isotope probing (DNA-SIP), we examined the relative importance and active community composition of ammonia-oxidizing archaea (AOA) and bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in soils under three land use types, forest, cropland, and greenhouse vegetable soil, representing three interference gradients. Soil net nitrification rate was in the order forest soil > cropland soil > greenhouse vegetable soil. DNA-SIP showed that active AOA outcompeted AOB in the forest soil, whereas AOB outperformed AOA in the cropland and greenhouse vegetable soils. Cropland soil was richer in NOB than in AOA and AOB. Phylogenetic analysis revealed that ammonia oxidation in the forest soil was predominantly catalyzed by the AOA Nitrosocosmicus franklandus cluster within the group 1.1b lineage. The 13C-labeled AOB were overwhelmingly dominated by Nitrosospira cluster 3 in the cropland soil. The active AOB Nitrosococcus watsonii lineage was observed in the greenhouse vegetable soil, and it played an important role in nitrification. Active NOB communities were closely affiliated with Nitrospira in the forest and cropland soils, and with Nitrolancea and Nitrococcus in the greenhouse vegetable soil. Canonical correlation analysis showed that soil pH and organic matter content significantly affected the active nitrifier community composition. These results suggest that land use types with different disturbance gradients alter the distribution of active nitrifier communities by affecting soil physicochemical properties. IMPORTANCE Nitrification plays an important role in the soil N cycle, and land use management has a profound effect on soil nitrifiers. It is unclear how different gradients of land use affect active ammonia-oxidizing archaea and bacteria and nitrite-oxidizing bacteria. Our research is significant because we determined the response of nitrifiers to human disturbance, which will greatly improve our understanding of the niche of nitrifiers and the differences in their physiology.


Assuntos
Agricultura , Amônia/metabolismo , Archaea/metabolismo , Bactérias/metabolismo , Florestas , Nitrificação , Nitritos/metabolismo , Archaea/genética , Processos Autotróficos , Bactérias/genética , Cinnamomum zeylanicum , DNA Arqueal/análise , DNA Bacteriano/análise , Concentração de Íons de Hidrogênio , Oxirredução , Filogenia , RNA Ribossômico 16S/análise , Solo/química , Microbiologia do Solo
15.
Mol Biol Rep ; 48(3): 2335-2350, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33811574

RESUMO

Mounting evidences have shown that nicotinamide adenine dinucleotide phosphate oxidase-2 (Nox-2) pathway modifies glutamic-acid decarboxylase-67 (GAD67) (GABAergic enzyme) and cholinergic systems via oxidative-nitrergic mechanisms in schizophrenia pathology. Rutin, a neuroactive antioxidant compound, with proven neuroprotective property has been shown to reduce schizophrenic-like behavior in mice. This study sought to investigate the mechanisms of action of the psychopharmacological activity of rutin in the preventive and reversal effects of ketamine-induced schizophrenic-like behavior, oxidative-nitrergic stress, cholinergic and GABAergic derangements in mice. In the preventive treatment, male mice were given rutin (0.1, 0.2 and 0.4 mg/kg) or risperidone (0.5 mg/kg) orally for 14 days prior to ketamine (20 mg/kg, i.p.) treatment from the 8 to 14th day. However, in the reversal treatment, ketamine was given for 14 days prior to rutin and risperidone. Behavioral (open-field, social-interaction and Y-maze tests), biochemical (oxidative/nitrergic stress markers, acetylcholinesterase activity), immunohistochemical (GAD67, Nox-2) and neuronal cell deaths in the striatum, prefrontal cortex, and hippocampus were evaluated. Ketamine-induced behavioral impairments were prevented and reversed by rutin. Exposure of mice to ketamine increased malondialdehyde, nitrite contents, acetylcholinesterase activity, neuronal cell death and Nox-2 expressions in the striatum, prefrontal cortex and hippocampus. Conversely, these derangements were prevented and reversed by rutin. The decreased glutathione levels due to ketamine were marked increased by rutin. Rutin only prevented ketamine-induced decrease in GAD67 expression in the striatal-hippocampal region. Altogether, the study showed that the prevention and reversal treatments of mice with rutin attenuated ketamine-induced schizophrenic-like behaviors via reduction of Nox-2 expression, oxidative/nitrergic stresses, acetylcholinesterase activity, and increased GAD67 enzyme.


Assuntos
Colinérgicos/metabolismo , Glutamato Descarboxilase/metabolismo , NADPH Oxidase 2/metabolismo , Estresse Oxidativo , Rutina/uso terapêutico , Esquizofrenia/genética , Esquizofrenia/prevenção & controle , Acetilcolinesterase/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Regulação para Baixo/efeitos dos fármacos , Glutationa/metabolismo , Ketamina , Locomoção/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Transtornos da Memória/complicações , Transtornos da Memória/tratamento farmacológico , Camundongos , Nitritos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Rutina/farmacologia , Esquizofrenia/induzido quimicamente , Esquizofrenia/tratamento farmacológico , Interação Social , Memória Espacial/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
16.
Int J Mol Sci ; 22(9)2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33925868

RESUMO

Nitric oxide (NO) is essential in the control of fetoplacental vascular tone, maintaining a high flow-low resistance circulation that favors oxygen and nutrient delivery to the fetus. Reduced fetoplacental blood flow is associated with pregnancy complications and is one of the major causes of fetal growth restriction (FGR). The reduction of dietary nitrate to nitrite and subsequently NO may provide an alternative source of NO in vivo. We have previously shown that nitrite induces vasorelaxation in placental blood vessels from normal pregnancies, and that this effect is enhanced under conditions of hypoxia. Herein, we aimed to determine whether nitrite could also act as a vasodilator in FGR. Using wire myography, vasorelaxant effects of nitrite were assessed on pre-constricted chorionic plate arteries (CPAs) and veins (CPVs) from normal and FGR pregnancies under normoxic and hypoxic conditions. Responses to the NO donor, sodium nitroprusside (SNP), were assessed in parallel. Nitrate and nitrite concentrations were measured in fetal plasma. Hypoxia significantly enhanced vasorelaxation to nitrite in FGR CPAs (p < 0.001), and in both normal (p < 0.001) and FGR (p < 0.01) CPVs. Vasorelaxation to SNP was also potentiated by hypoxia in both normal (p < 0.0001) and FGR (p < 0.01) CPVs. However, compared to vessels from normal pregnancies, CPVs from FGR pregnancies showed significantly lower reactivity to SNP (p < 0.01). Fetal plasma concentrations of nitrate and nitrite were not different between normal and FGR pregnancies. Together, these data show that nitrite-mediated vasorelaxation is preserved in FGR, suggesting that interventions targeting this pathway have the potential to improve fetoplacental blood flow in FGR pregnancies.


Assuntos
Retardo do Crescimento Fetal , Nitritos/farmacologia , Complicações na Gravidez/metabolismo , Vasodilatação/efeitos dos fármacos , Córion , Feminino , Retardo do Crescimento Fetal/tratamento farmacológico , Retardo do Crescimento Fetal/metabolismo , Feto/metabolismo , Humanos , Hipóxia , Miografia/métodos , Óxido Nítrico/metabolismo , Óxido Nítrico/farmacologia , Nitritos/metabolismo , Placenta/metabolismo , Circulação Placentária/efeitos dos fármacos , Circulação Placentária/fisiologia , Gravidez , Vasodilatadores/farmacologia
17.
J Biol Chem ; 296: 100476, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33652023

RESUMO

The hydroxylamine oxidoreductase (HAO) family consists of octaheme proteins that harbor seven bis-His ligated electron-transferring hemes and one 5-coordinate catalytic heme with His axial ligation. Oxidative HAOs have a homotrimeric configuration with the monomers covalently attached to each other via a unique double cross-link between a Tyr residue and the catalytic heme moiety of an adjacent subunit. This cross-linked active site heme, termed the P460 cofactor, has been hypothesized to modulate enzyme reactivity toward oxidative catalysis. Conversely, the absence of this cross-link is predicted to favor reductive catalysis. However, this prediction has not been directly tested. In this study, an HAO homolog that lacks the heme-Tyr cross-link (HAOr) was purified to homogeneity from the nitrite-dependent anaerobic ammonium-oxidizing (anammox) bacterium Kuenenia stuttgartiensis, and its catalytic and spectroscopic properties were assessed. We show that HAOr reduced nitrite to nitric oxide and also reduced nitric oxide and hydroxylamine as nonphysiological substrates. In contrast, HAOr was not able to oxidize hydroxylamine or hydrazine supporting the notion that cross-link-deficient HAO enzymes are reductases. Compared with oxidative HAOs, we found that HAOr harbors an active site heme with a higher (at least 80 mV) midpoint potential and a much lower degree of porphyrin ruffling. Based on the physiology of anammox bacteria and our results, we propose that HAOr reduces nitrite to nitric oxide in vivo, providing anammox bacteria with NO, which they use to activate ammonium in the absence of oxygen.


Assuntos
Oxirredutases/química , Oxirredutases/metabolismo , Planctomycetales/metabolismo , Compostos de Amônio/metabolismo , Bactérias/metabolismo , Catálise , Domínio Catalítico , Transporte de Elétrons/fisiologia , Heme/metabolismo , Hidrazinas/química , Hidroxilamina/química , Hidroxilaminas/química , Óxido Nítrico/metabolismo , Nitritos/metabolismo , Oxirredução , Tirosina/química , Tirosina/metabolismo
18.
J Biosci Bioeng ; 131(6): 663-670, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33757751

RESUMO

Nitrification is a key step in biological nitrogen transformation which depends on the performance of specialized microorganisms. Generally, nitrifying bacteria present a low growth rate and performance which can be improved when immobilized as a biofilm. The development of new materials suitable for the immobilization of nitrifying microorganisms is very important in nitrification and wastewater treatment. In this study, the effect of eggshell powder on biofilm formation by Nitrosomonas europaea an ammonium-oxidizing bacteria and Nitrobacter vulgaris a nitrite-oxidizing bacteria, on new polymeric supports were analyzed. Polylactic acid, polyvinyl chloride and polystyrene were tested to produce polymer-eggshells powder composites and used as biofilm supports for nitrifying bacteria. The support material was characterized to identify the most suitable polymer-eggshells powder combination for the cell adhesion and biofilm formation. The nitrification results showed a highest nitrate production of 42 mg NO3--N/L with polylactic acid-eggshell composite, with the best surface properties for cellular adhesion. Finally, scanning electron microscopy micrographs confirmed the best biofilm formed on polylactic acid-eggshell.


Assuntos
Casca de Ovo/química , Enzimas Imobilizadas/metabolismo , Nitratos/metabolismo , Nitrificação/fisiologia , Polímeros/química , Amônia/metabolismo , Compostos de Amônio/metabolismo , Animais , Bactérias/metabolismo , Biofilmes , Reatores Biológicos/microbiologia , Enzimas Imobilizadas/química , Nitritos/metabolismo , Nitrobacter/metabolismo , Nitrogênio/metabolismo , Nitrosomonas/metabolismo , Oxirredução , Purificação da Água/instrumentação , Purificação da Água/métodos
19.
Food Chem Toxicol ; 151: 112119, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33722603

RESUMO

Underutilized marine food products such as cephalopods' ink could be sources of bioactive compounds providing health benefits. This study aimed to assess the anti-proliferative and anti-inflammatory effects from Octopus vulgaris ink extracts (hexane-, ethyl acetate-, dichloromethane- (DM), and water extracts) using human colorectal (HT-29/HCT116) and breast (MDA-MB-231) cancer cells, and LPS-challenged murine RAW 264.7 cells. Except by ethyl-acetate, all of the extracts exhibited anti-proliferative effects without being cytotoxic to ARPE-19 and RAW 264.7 cells. Among DM fractions (F1/F2/F3), DM-F2 showed the highest anti-proliferative effect (LC50 = 52.64 µg/mL), inducing pro-apoptotic morphological disruptions in HCT116 cells. On RAW 264.7 cells, DM-F2 displayed the lowest nitrites reduction and up-regulation of key-cytokines from the JAK-STAT, PI3K-Akt, and IL-17 pathways. Compared to control, DM-F2 increased IL-4 and decreased NF-κB fluorometric expression in peripheral blood mononuclear cells (PBMCs). Metabolomic analysis of DM-F2 highlighted hexadecanoic acid and 1-(15-methyl-1-oxohexadecyl)-pyrrolidine as the most important metabolites. These compounds also exhibited high in silico binding affinity (-4.6 to -5.8 kcal/mol) to IL-1α, IL-1ß, and IL-2. Results suggested the joint immuno-modulatory and anti-proliferative effect derived from selected compounds of underutilized marine food products such as ink. This is the first report of such biological activities in extracts from O. vulgaris ink.


Assuntos
Anti-Inflamatórios/farmacologia , Proliferação de Células/efeitos dos fármacos , Octopodiformes/química , Animais , Citocinas/metabolismo , Células HCT116 , Humanos , Mediadores da Inflamação/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Metabolômica , Cloreto de Metileno/química , Camundongos , Nitritos/metabolismo , Células RAW 264.7 , Transdução de Sinais
20.
Eur J Appl Physiol ; 121(6): 1677-1688, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33675423

RESUMO

PURPOSE: The purpose of this study was to compare pulmonary and plasma markers of oxidative stress and inflammation after concentric and eccentric cycling bouts in individuals with chronic obstructive pulmonary disease (COPD). METHODS: Ten patients with moderate COPD level (68.3 ± 9.1 years; forced expiratory volume in 1 s = 68.6 ± 20.4% of predicted) performed 30 min of moderate-intensity concentric (CONC-M: 50% maximum concentric cycling power output; POmax) and eccentric cycling (ECC-M: 50% POmax), and high-intensity eccentric cycling (ECC-H: 100% POmax) in a randomised order. Cardiometabolic demand was monitored during cycling. Indirect markers of muscle damage were assessed before, immediately after, 24 and 48 h after cycling (muscle strength, muscle soreness and creatine kinase activity). Plasma oxidative stress (malondialdehyde: MDA), antioxidant (glutathione peroxidase activity: GPx) and inflammatory markers (IL-6, TNF-α) were measured before and 5 min after cycling. Exhaled breath condensate (EBC) samples were collected before and 15 min after cycling and analysed for hydrogen peroxide (H2O2), nitrites (NO2-) and pH. RESULTS: Cardiometabolic demand was 40-50% lesser for ECC-M than CONC-M and ECC-H. Greater muscle damage was induced after ECC-H than ECC-M and CONC-M. MDA decreased immediately after CONC-M (- 28%), ECC-M (- 14%), and ECC-H (- 17%), while GPx remained unchanged. IL-6 increased only after ECC-H (28%), while TNF-α remained unchanged after exercise. Pulmonary H2O2, NO2- and pH remained unchanged after exercise. CONCLUSION: These results suggest that only moderate muscle damage and inflammation were induced after high-intensity eccentric cycling, which did not induce pulmonary or plasmatic increases in markers of oxidative stress. TRIAL REGISTRATION NUMBER: Trial registration number: DRKS00009755.


Assuntos
Biomarcadores/metabolismo , Ergometria , Inflamação/metabolismo , Estresse Oxidativo/fisiologia , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Idoso , Ingestão de Energia/fisiologia , Feminino , Humanos , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Masculino , Força Muscular/fisiologia , Nitritos/metabolismo , Consumo de Oxigênio/fisiologia , Inquéritos e Questionários
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