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1.
Chemosphere ; 257: 127264, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32516671

RESUMO

Degradation of phenol by sodium persulfate (SPS) in hot compressed water (HCW) was investigated in a lab-built fused quartz tube reactor (FQTR) coupled with Raman spectroscopy system. The species of S2O82-, SO42-, HSO4-, SO32- and HSO3- in the reaction system were qualitatively and quantitatively analyzed by Raman spectroscopy. The hydrothermal stability of phenol and SPS at different temperature and the degradation of phenol by SPS were also studied. The results indicated that phenol was not stable in aqueous solution above 200 °C, and that only SO42- was generated in the hydrolysis of SPS at temperatures below 50 °C, and SO42- and HSO4- were generated at higher temperatures. The maximum conversion rate (90.93%) and mineralization efficiency (38.88%) of phenol by SPS was obtained at reaction temperature of 300 °C with 180 min reaction time. During the degradation of phenol by SPS, HSO4- was the main product and S∗ (not detected by Raman spectroscopy) exhibits a positive correlation with temperature. In addition, a degradation pathway of phenol by SPS was proposed. The degradation data for the kinetic analysis indicated that the reaction followed pseudo first-order kinetics, and the reaction rate constants (ks) were given as k50 °C = 0.0083 min-1, k100°C = 0.0197 min-1, k200 °C = 0.0498 min-1, k300 °C = 0.0619 min-1 and k400°C = 0.0505 min-1 at 30 min reaction. Moreover, the activation energy (12.580 kJ mol-1), the enthalpy change (9.064 kJ mol-1) and the entropy change (-222.104 J mol-1) of the reaction were also calculated.


Assuntos
Fenol/metabolismo , Compostos de Sódio/toxicidade , Sulfatos/toxicidade , Poluentes Químicos da Água/toxicidade , Temperatura Alta , Cinética , Oxirredução , Fenol/química , Compostos de Sódio/metabolismo , Análise Espectral Raman , Sulfatos/metabolismo , Temperatura , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos
2.
Proc Natl Acad Sci U S A ; 117(23): 12657-12664, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32461364

RESUMO

Blood-feeding arthropods produce antiinflammatory salivary proteins called evasins that function through inhibition of chemokine-receptor signaling in the host. Herein, we show that the evasin ACA-01 from the Amblyomma cajennense tick can be posttranslationally sulfated at two tyrosine residues, albeit as a mixture of sulfated variants. Homogenously sulfated variants of the proteins were efficiently assembled via a semisynthetic native chemical ligation strategy. Sulfation significantly improved the binding affinity of ACA-01 for a range of proinflammatory chemokines and enhanced the ability of ACA-01 to inhibit chemokine signaling through cognate receptors. Comparisons of evasin sequences and structural data suggest that tyrosine sulfation serves as a receptor mimetic strategy for recognizing and suppressing the proinflammatory activity of a wide variety of mammalian chemokines. As such, the incorporation of this posttranslational modification (PTM) or mimics thereof into evasins may provide a strategy to optimize tick salivary proteins for antiinflammatory applications.


Assuntos
Ácaros e Carrapatos/metabolismo , Proteínas de Artrópodes/metabolismo , Quimiocinas/antagonistas & inibidores , Processamento de Proteína Pós-Traducional , Saliva/metabolismo , Animais , Proteínas de Artrópodes/química , Quimiocinas/metabolismo , Células HEK293 , Humanos , Ligação Proteica , Sulfatos/metabolismo , Tirosina/metabolismo
3.
Nat Commun ; 11(1): 1878, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313021

RESUMO

Methane is the second most important greenhouse gas after carbon dioxide and approximately 11% of the global anthropogenic methane emissions originate from rice fields. Sulfate amendment is a mitigation strategy to reduce methane emissions from rice fields because sulfate reducers and methanogens compete for the same substrates. Cable bacteria are filamentous bacteria known to increase sulfate levels via electrogenic sulfide oxidation. Here we show that one-time inoculation of rice-vegetated soil pots with cable bacteria increases the sulfate inventory 5-fold, which leads to the reduction of methane emissions by 93%, compared to control pots lacking cable bacteria. Promoting cable bacteria in rice fields by enrichment or sensible management may thus become a strategy to reduce anthropogenic methane emissions.


Assuntos
Bactérias/metabolismo , Metano/metabolismo , Oryza/metabolismo , Solo/química , Agricultura , Ciclo do Carbono , Mudança Climática , Efeito Estufa , Gases de Efeito Estufa , Concentração de Íons de Hidrogênio , Metano/análise , Microeletrodos , Microbiologia do Solo , Sulfatos/metabolismo
4.
Int J Syst Evol Microbiol ; 70(5): 3219-3225, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32271141

RESUMO

A novel Gram-negative, non-spore-forming, vibrio-shaped, anaerobic, alkaliphilic, sulfate-reducing bacterium, designated strain PAR22NT, was isolated from sediment samples collected at an alkaline crater lake in Guanajuato (Mexico). Strain PAR22NT grew at temperatures between 15 and 37 °C (optimum, 32 °C), at pH between pH 8.3 and 10.1 (optimum, pH 9.0-9.6), and in the presence of NaCl up to 10 %. Pyruvate, 2-methylbutyrate and fatty acids (4-18 carbon atoms) were used as electron donors in the presence of sulfate as a terminal electron acceptor and were incompletely oxidized to acetate and CO2. Besides sulfate, both sulfite and elemental sulfur were also used as terminal electron acceptors and were reduced to sulfide. The predominant fatty acids were summed feature 10 (C18 : 1 ω7c and/or C18 : 1 ω9t and/or C18 : 1 ω12t), C18 : 1 ω9c and C16 : 0. The genome size of strain PAR22NT was 3.8 Mb including 3391 predicted genes. The genomic DNA G+C content was 49.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that it belongs to the genus Desulfobotulus within the class Deltaproteobacteria. Its closest phylogenetic relatives are Desulfobotulus alkaliphilus (98.4 % similarity) and Desulfobotulus sapovorans (97.9 % similarity). Based on phylogenetic, phenotypic and chemotaxonomic characteristics, we propose that the isolate represents a novel species of the genus Desulfobotulus with the name Desulfobotulus mexicanus sp. nov. The type strain is PAR22NT (=DSM 105758T=JCM 32146T).


Assuntos
Deltaproteobacteria/classificação , Lagos/microbiologia , Filogenia , Sulfatos/metabolismo , Álcalis , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Deltaproteobacteria/isolamento & purificação , Ácidos Graxos/química , Sedimentos Geológicos/microbiologia , México , Oxirredução , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Bactérias Redutoras de Enxofre/classificação , Bactérias Redutoras de Enxofre/isolamento & purificação
5.
Food Chem ; 320: 126652, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32229399

RESUMO

Enzymatic desulfation using arylsulfatase provides an attractive approach to improve agar quality. We have previously characterized a functional arylsulfatase from Pseudoalteromonas carrageenovora. To further improve its enzymatic performance, we isolated a mutant arylsulfatase of K253Q with improved enzyme activity from a random mutant library. Compared to wild-type arylsulfatase (WT), K253Q showed 33% increase in enzyme activity, with optimal temperature and pH of 55 °C and 8.0, respectively. K253Q demonstrated better substrate binding ability with lower Km value. Structure analysis indicated that a combination of the additional hydrogen bond and the enhanced substrate binding affinity could account for the improved enzyme activity of K253Q. K253Q exhibited about 54% sulfate removal against agar, resulting in additional 8% increase in 3,6-AG content and 20% increase in gel strength compared to WT. Scanning electron microscopy showed that K253Q treatment led to a stronger crosslinking structure of agar.


Assuntos
Ágar/química , Arilsulfatases/genética , Arilsulfatases/metabolismo , Pseudoalteromonas/enzimologia , Evolução Molecular Direcionada , Biblioteca Gênica , Concentração de Íons de Hidrogênio , Mutação , Sulfatos/isolamento & purificação , Sulfatos/metabolismo , Temperatura
6.
Ecotoxicol Environ Saf ; 194: 110402, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32151867

RESUMO

Sulfur (S) application in pakchoi (Brassica chinensis L.) cultivation is vital for reducing cadmium (Cd) accumulation in the plants. However, the mechanism of S application on Cd uptake and translocation in pakchoi is unclear. In this study, a hydroponic experiment was performed to investigate the effects of S application on Cd accumulation in pakchoi at one Cd concentration (50 µM, in comparison to the control condition, 0 µM) and three S levels (0, 2, 4 mM). The results showed that excessive S application (4 mM) reduced Cd accumulation and alleviated pakchoi growth inhibition caused by Cd stress in shoots and roots. With increased S application, the proportion of Cd in the vacuolar fraction and the proportion of NaCl-extractable Cd increased in roots. Additionally, S application increased the content of glutathione (GSH) and phytochelatins (PCs). The reduced Cd uptake and accumulation in pakchoi shoots could have been due to increased Cd chelation and vacuolar sequestration in roots. In addition, sufficient S application (2 mM) increased the expression of γ-glutamylcysteine synthetase (GSH1) and nicotinamide synthase (NAS) in roots, and excessive S application upregulated the expression of ATP sulfurylase (ATPS) and phytochelatin synthase (PCs). This study provides evidence for the mechanism of mitigating Cd toxicity in pakchoi and will be helpful for developing strategies to reduce Cd accumulation in the edible parts of pakchoi through S fertilizer application.


Assuntos
Brassica/efeitos dos fármacos , Cádmio/metabolismo , Poluentes do Solo/metabolismo , Sulfatos/farmacologia , Aminoaciltransferases/metabolismo , Transporte Biológico , Brassica/crescimento & desenvolvimento , Brassica/metabolismo , Cádmio/toxicidade , Fertilizantes/análise , Glutationa/metabolismo , Hidroponia , Modelos Teóricos , Fitoquelatinas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Poluentes do Solo/toxicidade , Sulfato Adenililtransferase/metabolismo , Sulfatos/metabolismo
7.
Poult Sci ; 99(2): 966-973, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32036988

RESUMO

The objective of this study was to evaluate the effect of dietary chloride (Cl) levels on performance, eggshell mechanical quality, and ultrastructure in layers based on the substitution of sodium chloride (NaCl) by sodium sulfate (Na2SO4). Three hundred sixty Jing Brown laying hens aged 43 wk were randomly divided into 5 groups and fed with corn-soybean meal diets containing 0.06, 0.10, 0.15, 0.20, and 0.25% total Cl inclusion. Every group had 8 replicates of 9 birds each. The feeding trial lasted for 12 wk. The results showed dietary 0.06% Cl due to complete substitution of NaCl by Na2SO4, depressed performance (P < 0.05) from 45 to 54 wk of age, increased serum creatinine level (P < 0.05), and caused visible renal tubular atrophy. Dietary Cl levels quadratically affected breaking strength, thickness, and weight of eggshell (P < 0.05). Better eggshell quality could be obtained when NaCl was partly replaced by Na2SO4 in laying hen diets maintaining Cl level at 0.10 or 0.15%. Moreover, the eggshell ash content was affected by Cl levels in a quadratic (P < 0.001) manner, with higher values observed in the 0.10 and 0.15% Cl groups (P < 0.05). Besides, the eggshell ultrastructural data showed that the total thickness and effective thickness significantly increased (P < 0.05) and mammillary thickness decreased (P < 0.05) in the group of dietary 0.15% Cl compared with the groups of 0.06 and 0.25% Cl. In conclusion, the complete substitution of dietary NaCl by Na2SO4 may induce Cl deficiency and depress laying performance and eggshell quality. Na2SO4 could partly replace NaCl in diets for laying hens (43-54 wk of age) without adverse effects on performance at the dietary Cl level from 0.10 to 0.25%. Better eggshell quality could be obtained when NaCl was partly replaced by Na2SO4 in laying hen diets maintaining Cl level at âˆ¼0.15%.


Assuntos
Galinhas/fisiologia , Casca de Ovo/química , Cloreto de Sódio/metabolismo , Sulfatos/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Relação Dose-Resposta a Droga , Casca de Ovo/efeitos dos fármacos , Feminino , Distribuição Aleatória , Cloreto de Sódio/administração & dosagem , Sulfatos/administração & dosagem
8.
Mar Pollut Bull ; 151: 110807, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056601

RESUMO

In this study, Acid-Volatile Sulfur (AVS), trace metals Cu, Cd and Zn and their chemical speciation based on BCR-sequential and simultaneous extraction (SEMs) in Antarctic lake sediments (Y2-1 and YO) were analyzed to investigate the restriction of sulfate reduction on the bioavailability and toxicity of trace metals. Much higher trace metals in Y2-1 indicating a primary source from penguin guano. The main chemical speciation of Cu and Cd in Y2-1 was their oxidizable fraction in contrast to those of weak-acid extraction in YO. Lower ratio of ΣSEM/AVS in Y2-1 indicating less toxicity of the trace metals. The main chemical speciation of Cd in Y2-1 was their oxidizable fraction in contrast to that exchangeable fraction in penguin guano, indicating that although amounts of Cd was transported from marine to lake by penguins, strong sulfate reduction in ornithogenic sediments restricts the bioavailability and toxicity of Cd through the formation of insoluble sulfide.


Assuntos
Monitoramento Ambiental , Metais Pesados/toxicidade , Sulfatos/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Regiões Antárticas , Disponibilidade Biológica , Sedimentos Geológicos , Lagos , Metais Pesados/análise , Poluentes Químicos da Água/análise
9.
PLoS One ; 15(2): e0227856, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084141

RESUMO

Despite the significant progress in characterizing mechanical functions of individual scleral extracellular matrix (ECM) components, the biomechanical contribution of sulfated glycosaminoglycans (sGAGs) is still poorly understood. The primary purpose of this study was to determine the possible function of sGAGs in scleral mechanical response by characterizing the tensile behavior of normal and sGAG-depleted samples. We used chondroitinase ABC solution to remove sGAGs from scleral samples that were dissected from posterior porcine eyes. We performed biochemical analyses for assessing the efficacy of sGAG removal protocol. Furthermore, we conducted stress-controlled uniaxial tensile tests to characterize the influence of sGAG removal on mechanical properties of sclera. The tensile behavior of scleral strips right after dissection and after being soaked in buffer was also determined. Biochemical analyses confirmed that 18 hour incubation in 0.125 U/ml Chondroitinase ABC solution removed over 90% of chondroitin and dermatan sGAGs. No significant difference was observed in the thickness/hydration of samples because of enzyme- and buffer-treated samples. Furthermore, it was found that sGAG depletion did not significantly alter the tangent modulus, energy dissipation, and peak strain of posterior scleral strips. It was concluded that sGAGs did not influence the stress-controlled viscoelastic tensile response of sclera.


Assuntos
Glicosaminoglicanos/metabolismo , Esclera/fisiopatologia , Estresse Mecânico , Sulfatos/metabolismo , Resistência à Tração , Animais , Elasticidade , Colágenos Fibrilares/metabolismo , Tamanho do Órgão , Suínos , Viscosidade
10.
Chemosphere ; 250: 126259, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32092575

RESUMO

In this study, single-chamber bioelectrochemical reactors (EMNS) were used to investigate the methane oxidation driven by sulfate and nitrite reduction with the auxiliary voltage. Results showed that the methane oxidation was simultaneously driven by sulfate and nitrite reduction, with more methane being converted using the auxiliary voltage. When the voltage was 1.6 V, the maximum removal rate was achieved at 8.05 mg L-1 d-1. Carbon dioxide and methanol were the main products of methane oxidation. Simultaneously, nitrogen, nitrous oxide, sulfur ions, and hydrogen sulfide were detected as products of sulfate and nitrite reduction. Microbial populations were analyzed by qPCR and high-throughput sequencing. The detected methanotrophs included Methylocaldum sp., Methylocystis sp., Methylobacter sp. and M. oxyfera. The highest abundance of M. oxyfera was (3.97 ± 0.32) × 106 copies L-1 in the EMNS-1.6. The dominant nitrite-reducing bacteria were Ignavibacterium sp., Hyphomicrobium sp., Alicycliphilus sp., and Anammox bacteria. Desulfovibrio sp., Desulfosporosinus sp. and Thiobacillus sp. were related to the sulfur cycle. Ignavibacterium sp., Thiobacillus sp. and Desulfovibrio sp. may transfer electrons with electrodes using humic acids as the electronic shuttle. The possible pathways included (1) Methane was mainly oxidized to carbon dioxide and dissolved organic matters by methanotrophs utilizing the oxygen produced by the disproportionation in the cells of M. oxyfera. (2) Nitrite was reduced to nitrogen by heterotrophic denitrifying bacteria with dissolved organic compounds. (3) Desulfovibrio sp. and Desulfosporosinus sp. reduced sulfate to sulfur ions. Thiobacillus sp. oxidized sulfur ions to sulfur or sulfate using nitrite as the electron acceptor.


Assuntos
Reatores Biológicos/microbiologia , Metano/metabolismo , Nitritos/metabolismo , Anaerobiose , Bactérias/metabolismo , Desnitrificação , Nitrogênio/metabolismo , Oxirredução , Sulfatos/metabolismo
11.
ISME J ; 14(3): 815-827, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31896791

RESUMO

The genus Desulfoluna comprises two anaerobic sulfate-reducing strains, D. spongiiphila AA1T and D. butyratoxydans MSL71T, of which only the former was shown to perform organohalide respiration (OHR). Here we isolated a third strain, designated D. spongiiphila strain DBB, from marine intertidal sediment using 1,4-dibromobenzene and sulfate as the electron acceptors and lactate as the electron donor. Each strain harbors three reductive dehalogenase gene clusters (rdhABC) and corrinoid biosynthesis genes in their genomes, and dehalogenated brominated but not chlorinated organohalogens. The Desulfoluna strains maintained OHR in the presence of 20 mM sulfate or 20 mM sulfide, which often negatively affect other organohalide-respiring bacteria. Strain DBB sustained OHR with 2% oxygen in the gas phase, in line with its genetic potential for reactive oxygen species detoxification. Reverse transcription-quantitative PCR revealed differential induction of rdhA genes in strain DBB in response to 1,4-dibromobenzene or 2,6-dibromophenol. Proteomic analysis confirmed expression of rdhA1 with 1,4-dibromobenzene, and revealed a partially shared electron transport chain from lactate to 1,4-dibromobenzene and sulfate, which may explain accelerated OHR during concurrent sulfate reduction. Versatility in using electron donors, de novo corrinoid biosynthesis, resistance to sulfate, sulfide and oxygen, and concurrent sulfate reduction and OHR may confer an advantage to marine Desulfoluna strains.


Assuntos
Deltaproteobacteria/isolamento & purificação , Deltaproteobacteria/metabolismo , Água do Mar/microbiologia , Sulfatos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Corrinoides/biossíntese , Deltaproteobacteria/classificação , Deltaproteobacteria/genética , Halogenação , Família Multigênica , Oxirredução , Proteômica
12.
J Anim Sci ; 98(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31909792

RESUMO

An isotope tracer study was conducted to evaluate the effects of immune system stimulation (ISS) on the irreversible loss of cysteine (Cys) to taurine (Tau) and sulfate (SO4), as well as glutathione (GSH) synthesis, during the fed state in pigs. We previously have reported that ISS increases plasma Cys flux and the GSH synthesis rate at the tissue and whole-body levels in growing pigs. Thus, the current article presents the data on the irreversible loss of Cys during ISS in pigs. Ten gilts (BW: 7.0 ±â€…0.12 kg) were feed restricted a sulfur amino acids (SAA) limiting diet and injected twice with either saline (n = 4) or increasing amounts of E. coli lipopolysaccharide (n = 6). The day after the second injection, a 5-h primed continuous intravenous infusion of 35S-Cys was conducted. ISS reduced plasma Cys and total SAA concentrations (16% and 21%, respectively; P < 0.05). However, ISS had no effect on the plasma concentrations of Tau and SO4, nor did it affect the appearance of 35S in plasma Tau, plasma SO4, urinary Tau, or urinary SO4 (P > 0.19). On a whole-body basis and including urinary excretion, ISS increased the appearance of 35S in Tau by 67% (P < 0.05), but tended to decrease the appearance of 35S in SO4 by 22% (P < 0.09). Overall, the current findings indicate that during ISS, decreased plasma SAA concentrations and increased plasma Cys flux are attributed in part to increased rates of Cys conversion to Tau, but not Cys catabolism to SO4. Thus, increased utilization of Cys for the synthesis of immune system metabolites, such as GSH and Tau, is likely the main contributor to increased Cys flux during ISS in pigs. In addition, the irreversible loss of Cys during ISS is small and has a minimal impact on the daily SAA requirements of starter pigs.


Assuntos
Cisteína/metabolismo , Sistema Imunitário/efeitos dos fármacos , Suínos/fisiologia , Taurina/metabolismo , Ração Animal , Animais , Dieta/veterinária , Escherichia coli/química , Feminino , Glutationa/metabolismo , Lipopolissacarídeos/administração & dosagem , Sulfatos/metabolismo , Suínos/imunologia
13.
J Ind Microbiol Biotechnol ; 47(1): 21-33, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31758413

RESUMO

Bioleaching, an alternative environmental smelting technology, typically uses high concentrations of heavy metal ions, especially in the subsequent phase, due to metal ion accumulation from the mineral. In this study, we analyzed the overall response of the bioleaching microorganism Acidithiobacillus caldus to copper stress through physiological and transcriptomic analyses. Scanning electron microscopy results showed higher extracellular polymeric substances secretion and cell aggregation under copper stress. Intracellular levels of glutamic acid, glycine and cysteine increased, favoring the synthesis of glutathione for maintenance of the oxidation-reduction state. GSH, during copper stress conditions, the activity of GSH-PX and CAT increased, resulting in reduced oxidative damage while maintaining stable intracellular pH. Higher unsaturated and cyclopropane fatty acid levels resulted in increased membrane fluidity and compactness and decreased ATP levels to support the energy requirements for stress resistance. Initially, H+-ATPase activity increased to provide energy for proton output and decreased later at higher copper ion stress. From transcriptome analysis, 140 genes were differentially expressed under low copper stress (1 g/L), while 250 genes exhibited altered transcriptional levels at higher copper stress (3 g/L). These differentially expressed genes were involved primarily in metabolic pathways such as energy metabolism, two-component systems, amino acid metabolism, and signal transduction. The Sox family cluster gene cluster involved in the conversion of thiosulfate to sulfate was upregulated in the sulfur metabolism pathway. In the oxidative phosphorylation pathway, genes participating in the synthesis of NADH oxidoreductase and cytochrome c oxidase, nuoL, cyoABD (cyoA, cyoB and cyoD) and cydAB (cydA and cydB), were downregulated. The TCS element ompR, closely associated with the osmotic pressure, exhibited active response, while Cu2+ efflux system gene cusRS was upregulated. In the amino acid metabolism, the glnA involved in nitrogen fixation was upregulated and promoted the synthesis of glutamine synthetase for reducing excessive oxidative stress. This study provides new insights into the mechanism underlying A. caldus response to heavy-metal ion stress under harsh bioleaching conditions.


Assuntos
Acidithiobacillus/metabolismo , Cobre/metabolismo , Acidithiobacillus/efeitos dos fármacos , Cobre/farmacologia , Cisteína/metabolismo , Perfilação da Expressão Gênica , Redes e Vias Metabólicas , Oxirredução , Sulfatos/metabolismo
14.
Anal Bioanal Chem ; 412(2): 335-342, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31788715

RESUMO

Triclosan (TCS) is an antibacterial and antifungal compound found in many hygiene products, including toothpaste, soap, and detergents. However, this molecule can act as an endocrine disruptor and can induce harmful effects on human health and the environment. In this study, triclosan was biotransformed in vitro using human and rat liver fractions, to evaluate oxidative metabolism, the formation of reactive metabolites via the detection of GSH adducts, as well as glucuronide and sulfate conjugates using liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-HRMS/MS). A deuterated analog of triclosan was also employed for better structural elucidation of specific metabolic sites. Several GSH adducts were found, either via oxidative metabolism of triclosan or its cleavage product, 2,4-dichlorophenol. We also detected glucuronide and sulfated conjugates of triclosan and its cleaved product. This study was aimed at understanding the routes of detoxification of this xenobiotic, as well as investigating any potential pathways related to additional toxicity via reactive metabolite formation. Graphical abstract.


Assuntos
Anti-Infecciosos Locais/metabolismo , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Triclosan/metabolismo , Animais , Glucuronídeos/metabolismo , Glutationa/metabolismo , Humanos , Microssomos Hepáticos/metabolismo , Oxirredução , Ratos , Sulfatos/metabolismo
15.
Chemosphere ; 244: 125508, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31812042

RESUMO

Two H2-based membrane biofilm reactor (H2-MBfR) systems, differing in membrane type, were tested for sulfate reduction from a real mining-process water having low alkalinity and high concentrations of dissolved sulfate and calcium. Maximum sulfate reductions were 99%, with an optimum pH range between 8 and 8.5, which minimized any toxic effect of unionized hydrogen sulfide (H2S) on sulfate-reducing bacteria (SRB) and calcite scaling on the fibers and in the biofilm. Although several strategies for control of pH and gas back-diffusion were applied, it was not possible to sustain a high degree of sulfate reduction over the long-term. The most likely cause was precipitation of calcite inside the biofilm and on the surface of fibers, which was shown by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) analysis. Another possible cause was a decline in pH, leading to inhibition by H2S. A H2/CO2 mixture in the gas supply was able to temporarily recover the effectiveness of the reactors and stabilize the pH. Biomolecular analysis showed that the biofilm was comprised of 15-20% SRB, but a great variety of autotrophic and heterotrophic genera, including sulfur-oxidizing bacteria, were present. Results also suggest that the MBfR system can be optimized by improving H2 mass transfer using fibers of higher gas permeability and by feeding a H2/CO2 mixture that is automatically adjusted for pH control.


Assuntos
Reatores Biológicos/microbiologia , Mineração , Sulfatos/metabolismo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Processos Autotróficos , Bactérias , Biofilmes , Hidrogênio/química , Membranas , Membranas Artificiais , Oxirredução , Sulfatos/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos
16.
Nat Prod Res ; 34(6): 797-803, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30398375

RESUMO

Previous studies have revealed sulfation as a major pathway for the metabolism of hesperetin, naringenin and apigenin. The current study was designed to identify the human cytosolic sulfotransferase (SULT) enzyme(s) capable of sulfating these flavonoid compounds. Of the thirteen human SULTs, six (1A1, 1A2, 1A3, 1B2, 1C4, 1E1) displayed significant sulfating activity toward hesperetin, five (1A1, 1A2, 1A3, 1B2, 1C4) displayed sulfating activity towards naringenin, and four (1A1, 1A2, 1A3, 1C4) showed sulfating activity towards apigenin. Of the four human organ specimens tested, liver and intestine cytosols displayed much higher hesperetin-, naringenin- and apigenin-sulfating activity than lung and kidney cytosols. Moreover, sulfation of hesperetin, naringenin and apigenin was shown to take place in HepG2 human hepatoma cells and Caco-2 human colon adenocarcinoma cells under cultured conditions. Taken together, these results provided a biochemical basis underlying the metabolism of hesperetin, naringenin and apigenin through sulfation in humans.[Formula: see text].


Assuntos
Apigenina/metabolismo , Flavanonas/metabolismo , Hesperidina/metabolismo , Redes e Vias Metabólicas , Sulfatos/metabolismo , Sulfotransferases/metabolismo , Linhagem Celular Tumoral , Citosol/enzimologia , Humanos , Mucosa Intestinal/metabolismo , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo
17.
ISME J ; 14(2): 450-462, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31659234

RESUMO

Inhibitors can be used to control the functionality of microbial communities by targeting specific metabolisms. The targeted inhibition of dissimilatory sulfate reduction limits the generation of toxic and corrosive hydrogen sulfide across several industrial systems. Sulfate-reducing microorganisms (SRM) are specifically inhibited by sulfate analogs, such as perchlorate. Previously, we showed pure culture SRM adaptation to perchlorate stress through mutation of the sulfate adenylyltransferase, a central enzyme in the sulfate reduction pathway. Here, we explored adaptation to perchlorate across unconstrained SRM on a community scale. We followed natural and bio-augmented sulfidogenic communities through serial transfers in increasing concentrations of perchlorate. Our results demonstrated that perchlorate stress altered community structure by initially selecting for innately more resistant strains. Isolation, whole-genome sequencing, and molecular biology techniques allowed us to define subsequent genetic mechanisms of adaptation that arose across the dominant adapting SRM. Changes in the regulation of divalent anion:sodium symporter family transporters led to increased intracellular sulfate to perchlorate ratios, allowing SRM to escape the effects of competitive inhibition. Thus, in contrast to pure-culture results, SRM in communities cope with perchlorate stress via changes in anion transport and its regulation. This highlights the value of probing evolutionary questions in an ecological framework, bridging the gap between ecology, evolution, genomics, and physiology.


Assuntos
Evolução Molecular , Percloratos/toxicidade , Sulfatos/metabolismo , Ânions/metabolismo , Bactérias/genética , Bactérias/metabolismo , Transporte Biológico , Oxirredução , Percloratos/metabolismo , Sulfato Adenililtransferase/genética
18.
Environ Microbiol ; 22(2): 783-795, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31854015

RESUMO

Dissimilatory sulphite reductase DsrAB occurs in sulphate/sulphite-reducing prokaryotes, in sulphur disproportionators and also in sulphur oxidizers, where it functions in reverse. Predictions of physiological traits in metagenomic studies relying on the presence of dsrAB, other dsr genes or combinations thereof suffer from the lack of information on crucial Dsr proteins. The iron-sulphur flavoprotein DsrL is an example of this group. It has a documented essential function during sulphur oxidation and was recently also found in some metagenomes of probable sulphate and sulphite reducers. Here, we show that DsrL and reverse acting rDsrAB can form a complex and are copurified from the phototrophic sulphur oxidizer Allochromatium vinosum. Recombinant DsrL exhibits NAD(P)H:acceptor oxidoreductase activity with a strong preference for NADH over NADPH. In vitro, the rDsrABL complex effectively catalyses NADH-dependent sulphite reduction, which is strongly enhanced by the sulphur-binding protein DsrC. Our work reveals NAD+ as suitable in vivo electron acceptor for sulphur oxidation in organisms operating the rDsr pathway and points to reduced nicotinamide adenine dinucleotides as electron donors for sulphite reduction in sulphate/sulphite-reducing prokaryotes that contain DsrL. In addition, dsrL cannot be used as a marker distinguishing sulphate/sulphite reducers and sulphur oxidizers in metagenomic studies without further analysis.


Assuntos
Chromatiaceae/metabolismo , Sulfito de Hidrogênio Redutase/metabolismo , NAD/metabolismo , Sulfatos/metabolismo , Sulfitos/metabolismo , Proteínas de Bactérias/metabolismo , Transporte de Elétrons , Elétrons , NADP/metabolismo , Oxirredução , Enxofre/metabolismo
19.
BMC Mol Cell Biol ; 20(Suppl 3): 52, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31823720

RESUMO

BACKGROUND: Proteins perform their functions by interacting with acid radical ions. Recently, it was a challenging work to precisely predict the binding residues of acid radical ion ligands in the research field of molecular drug design. RESULTS: In this study, we proposed an improved method to predict the acid radical ion binding residues by using K-nearest Neighbors classifier. Meanwhile, we constructed datasets of four acid radical ion ligand (NO2-, CO32-, SO42-, PO43-) binding residues from BioLip database. Then, based on the optimal window length for each acid radical ion ligand, we refined composition information and position conservative information and extracted them as feature parameters for K-nearest Neighbors classifier. In the results of 5-fold cross-validation, the Matthew's correlation coefficient was higher than 0.45, the values of accuracy, sensitivity and specificity were all higher than 69.2%, and the false positive rate was lower than 30.8%. Further, we also performed an independent test to test the practicability of the proposed method. In the obtained results, the sensitivity was higher than 40.9%, the values of accuracy and specificity were higher than 84.2%, the Matthew's correlation coefficient was higher than 0.116, and the false positive rate was lower than 15.4%. Finally, we identified binding residues of the six metal ion ligands. In the predicted results, the values of accuracy, sensitivity and specificity were all higher than 77.6%, the Matthew's correlation coefficient was higher than 0.6, and the false positive rate was lower than 19.6%. CONCLUSIONS: Taken together, the good results of our prediction method added new insights in the prediction of the binding residues of acid radical ion ligands.


Assuntos
Carbonatos/química , Biologia Computacional/métodos , Nitritos/química , Fosfatos/química , Proteínas/química , Proteínas/metabolismo , Sulfatos/química , Sítios de Ligação , Carbonatos/metabolismo , Bases de Dados de Proteínas , Ligantes , Nitritos/metabolismo , Fosfatos/metabolismo , Sulfatos/metabolismo
20.
BMC Mol Cell Biol ; 20(Suppl 3): 53, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31823742

RESUMO

BACKGROUND: In many important life activities, the execution of protein function depends on the interaction between proteins and ligands. As an important protein binding ligand, the identification of the binding site of the ion ligands plays an important role in the study of the protein function. RESULTS: In this study, four acid radical ion ligands (NO2-,CO32-,SO42-,PO43-) and ten metal ion ligands (Zn2+,Cu2+,Fe2+,Fe3+,Ca2+,Mg2+,Mn2+,Na+,K+,Co2+) are selected as the research object, and the Sequential minimal optimization (SMO) algorithm based on sequence information was proposed, better prediction results were obtained by 5-fold cross validation. CONCLUSIONS: An efficient method for predicting ion ligand binding sites was presented.


Assuntos
Carbonatos/química , Biologia Computacional/métodos , Metais/química , Nitritos/química , Fosfatos/química , Proteínas/química , Sulfatos/química , Algoritmos , Sítios de Ligação , Carbonatos/metabolismo , Íons/química , Íons/metabolismo , Ligantes , Metais/metabolismo , Nitritos/metabolismo , Fosfatos/metabolismo , Ligação Proteica , Proteínas/metabolismo , Sulfatos/metabolismo
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