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1.
Chemosphere ; 279: 130882, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34134437

RESUMO

A novel direct dual Z-scheme 3DOM (three-dimensional ordered macropores) SnS2-ZnS/ZrO2 composite was prepared by the template method combined with the in situ sulfur replacement technology. The composition, structure, morphology, and surface physicochemical properties of the composites were well characterized. The results indicate that it possesses a uniform and periodical macroporous structure, a large surface area (121.1 m2 g-1), broad visible light absorption, and high separation ability of photoinduced electron/hole pairs. 3DOM SnS2-ZnS/ZrO2 composite removed 96.8% of methyl orange within 210 min of simulated sunlight irradiation. Moreover, photocatalytic hydrogen production achieved the rate of 928.1 µmol g-1, which was 66.3 times as high as that of the commercial P25 after 8 h simulated sunlight irradiation. The enhanced photocatalytic performance mainly attributed to the direct dual Z-scheme system, which improves the charge separation efficiency and optimizes the charge transfer pathway. The charge transfer mechanism over the 3DOM SnS2-ZnS/ZrO2 is discussed in detail based on the results of radical trapping experiments. Our work paves a new way to design 3DOM materials with direct dual Z-scheme structure.


Assuntos
Sulfetos , Compostos de Zinco , Catálise , Hidrogênio
2.
Talanta ; 232: 122467, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074439

RESUMO

Hydrogen polysulfide (H2Sn, n > 1), a member of reactive sulfur species (RSS), is primarily generated during the crosstalk between H2S and reactive oxygen species (ROS), which plays important role in physiological and pathological processes. Ferroptosis is a new non-classical mode of cell death, in which ROS-associated lipid peroxidation and iron-dependent accumulation are the main features. However, the biological effects of H2Sn on ferroptosis and the detailed mechanisms of action remain poorly understood. Thus, there is an urgent need to develop highly selective and sensitive chemical tools for monitoring H2Sn in living cells. Herein, we develop a two-photon fluorescent probe (PSP) for specifically imaging H2Sn in live cells and tumor spheroids. This probe exhibited a sensitive and selective response to H2Sn, which had been used for imaging exogenous and endogenous H2Sn in living cells by confocal imaging and high content imaging. PSP exhibits excellent photo-stability and two-photon imaging performance when irradiating at 880 nm in 3D HeLa multicellular tumor spheroids. Importantly, our studies revealed that H2Sn levels were significantly up-regulated during ferroptosis. These excellent properties ensure that PSP is a promising two-photon probe for exploring the biological and pathological effects of H2Sn during ferroptosis.


Assuntos
Ferroptose , Sulfeto de Hidrogênio , Corantes Fluorescentes , Humanos , Hidrogênio , Sulfetos
3.
Nat Commun ; 12(1): 3389, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099672

RESUMO

Bioorthogonal late-stage diversification of amino acids and peptides bears enormous potential for drug discovery and molecular imaging. Despite major accomplishments, these strategies largely rely on traditional, lengthy prefunctionalization methods, heavily involving precious transition-metal catalysis. Herein, we report on a resource-economical manganese(I)-catalyzed C-H fluorescent labeling of structurally complex peptides ensured by direct alkynylation and alkenylation manifolds. This modular strategy sets the stage for unraveling structure-activity relationships between structurally discrete fluorophores towards the rational design of BODIPY fluorogenic probes for real-time analysis of immune cell function.


Assuntos
Técnicas de Química Sintética/métodos , Corantes Fluorescentes/síntese química , Manganês/química , Peptídeos/síntese química , Compostos de Boro/química , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Carbono/química , Catálise , Membrana Celular/metabolismo , Humanos , Hidrogênio/química , Células Jurkat , Microscopia Confocal , Microscopia de Fluorescência , Imagem Molecular/métodos
4.
Environ Res ; 198: 111221, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33971131

RESUMO

The difficulty and long duration of start-up wastes numerous costs, labors and time and a little fluctuate during the process might fail it. However, studies dealing with the problem hindering accelerated start-up are still insufficient. Current research focused to develop a method for accelerated start-up in an efficient way. This work outlined a novel alternative for accelerated start-up. This joint method, adding waste effluent with applying biofilm reactor, could successfully start up hydrogen production in the first 24 h via increasing ability of hydrogen producers while the control group produced little hydrogen. The two factors, biofilm formation and addition of waste effluent, expressed the combined effects on accelerated start-up. This study suggested that little molecules like quorum sensing system factors and indoles might be the crucial regulating and stimulating factors and express the accelerated start-up ability only in biofilm reactors.


Assuntos
Biofilmes , Eliminação de Resíduos Líquidos , Reatores Biológicos , Fermentação , Hidrogênio , Percepção de Quorum
5.
Nat Commun ; 12(1): 2894, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001911

RESUMO

Development of practical deuteration reactions is highly valuable for organic synthesis, analytic chemistry and pharmaceutic chemistry. Deuterodehalogenation of organic chlorides tends to be an attractive strategy but remains a challenging task. We here develop a photocatalytic system consisting of an aryl-amine photocatalyst and a disulfide co-catalyst in the presence of sodium formate as an electron and hydrogen donor. Accordingly, many aryl chlorides, alkyl chlorides, and other halides are converted to deuterated products at room temperature in air (>90 examples, up to 99% D-incorporation). The mechanistic studies reveal that the aryl amine serves as reducing photoredox catalyst to initiate cleavage of the C-Cl bond, at the same time as energy transfer catalyst to induce homolysis of the disulfide for consequent deuterium transfer process. This economic and environmentally-friendly method can be used for site-selective D-labeling of a number of bioactive molecules and direct H/D exchange of some drug molecules.


Assuntos
Alcanos/química , Cloretos/química , Halogenação , Halogênios/química , Hidrogênio/química , Alcanos/síntese química , Catálise/efeitos da radiação , Cloretos/síntese química , Luz , Modelos Químicos , Estrutura Molecular , Fenômenos de Química Orgânica
6.
Bioresour Technol ; 335: 125264, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34004562

RESUMO

Anaerobic digestion of garden waste was investigated in a two-stage process consisting of hyperthermophilic pretreatment followed by mesophilic or thermophilic fermentation. The greatest digestion performance was achieved when the substrates were first treated at 70 °C for 3 days with no inoculation, and then mixed with inoculum (anaerobic sludge) and subjected to anaerobic digestion at 55 °C. Under such conditions, the maximum methane and hydrogen yields from grass were 517 NmlCH4/kgVS and 52 NmlH2/kgVS, whereas the corresponding values for leaves were 421 NmlCH4/kgVS and 23 NmlH2/kgVS, and these figure were far greater than the yields obtained in experiments with no hyperthermophilic stage. A metagenomic analysis of hyperthermophilic environments revealed the appearance of thermophilic and hyperthermophilic bacteria showing hydrolytic activity against lignocellulosic materials, including Caldicellulosiruptor, Thermovenabulum, Thermoanaerobacter, Moorella, Tepimicrobium, Geobacillus and Thermobacillus at a genus level. A noticeable methane production in the hyperthermophilic stage could be linked to the presence of Methanothermobacter sp.


Assuntos
Reatores Biológicos , Metano , Anaerobiose , Jardins , Hidrogênio , Esgotos
7.
Bioresour Technol ; 335: 125268, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34020157

RESUMO

Anaerobic dark fermentation (DF) performances of food waste (FW) were investigated using oyster shells. The different amount oyster shells(6%-12%(w/w)) were added to the DF system of FW. The result showed that the H2 production rate and cumulative H2 production improved after addition oyster shells. The highest H2 production rate and cumulative H2 production of 8% oyster shells addition group were 8.4 mL/(gVS·h) and 88.2 mL/gVS, which were 11.7%-30.6% and 17.4%-52.9% higher than those of the other test groups. TVFAs production, especially acetic and butyric acids improved after addition oyster shells. The highest TVFAs production was 19291.4 mg/L for 8% oyster shells added group, which was 90.24% higher than that of the unadded group. For 8% oyster shells added group, Lactobacillales, Gallicola, and Bacteroides were the dominant species at genus levels. Thus, the addition of an appropriate amount oyster shells could improve H2 production rate, cumulative H2 production, promote buffering capacity, enhance TVFAs production.


Assuntos
Microbiota , Ostreidae , Eliminação de Resíduos , Anaerobiose , Animais , Reatores Biológicos , Fermentação , Alimentos , Hidrogênio , Concentração de Íons de Hidrogênio
8.
ACS Chem Neurosci ; 12(11): 1972-1982, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-33988976

RESUMO

Mutations of the Amyloid Precursor Protein, from which the amyloid ß peptide Aß42 is cleaved, are associated with familial Alzheimer's disease. The disease-relevant familial mutations include the Arctic (E22G), Iowa (D23N), Italian (E22K), Dutch (E22Q), Japanese (D7N), English (D6R), and Flemish (A21G) variants. A detailed mechanistic understanding of the aggregation behavior of the mutant peptides at the residue level is, however, still lacking. We report here a study of the aggregation kinetics of these mutants in vitro by pulsed hydrogen-deuterium exchange mass spectrometry (HDX-MS) to obtain a temporally and sequence resolved picture of their self-assembly. For all variants, HDX occurs to give a bimodal distribution representing two soluble classes of aggregates, one protected and one solvent-exposed. There is no evidence of other classes of structural intermediates within the detection limits of the HDX approach. The fractional changes in the bimodal exchange profiles for several regions of Aß42 reveal that the central and C-terminal peptides gain protection upon fibril formation, whereas the N-terminal regions remain largely solvent-accessible. For these mutants, all peptide fragments follow the same kinetics, acquiring solvent protection at the same time, further supporting that there are no significant populations of intermediate species under our experimental conditions. The results demonstrate the potential of pulsed HDX-MS for resolving the region-specific aggregation behavior of Aß42 isoforms in solution where X-ray crystallography and solid-state NMR (ssNMR) are challenged.


Assuntos
Doença de Alzheimer , Doença de Alzheimer/genética , Peptídeos beta-Amiloides , Deutério , Medição da Troca de Deutério , Humanos , Hidrogênio , Fragmentos de Peptídeos
9.
Stud Health Technol Inform ; 279: 54-61, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-33965919

RESUMO

Hydrogen breath tests are a well-established method to help diagnose functional intestinal disorders such as carbohydrate malabsorption or small intestinal bacterial overgrowth. In this work we apply unsupervised machine learning techniques to analyze hydrogen breath test datasets. We propose a method that uses 26 internal cluster validation measures to determine a suitable number of clusters. In an induced external validation step we use a predefined categorization proposed by a medical expert. The results indicate that the majority of the considered internal validation indexes was not able to produce a reasonable clustering. Considering a predefined categorization performed by a medical expert, a novel shape-based method obtained the highest external validation measure in terms of adjusted rand index. The predefined clusterings constitute the basis of a supervised machine learning step that is part of our ongoing research.


Assuntos
Infecções Bacterianas , Testes Respiratórios , Análise por Conglomerados , Humanos , Hidrogênio , Aprendizado de Máquina não Supervisionado
10.
BMC Gastroenterol ; 21(1): 211, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33971823

RESUMO

BACKGROUND: Pancreatic exocrine insufficiency (PEI) is associated with the outcome of pancreatic disease. However, there is no method for assessing PEI that can be used noninvasively and easily for outpatient. It has been reported that changes in intestinal bacteria caused by PEI may increase breath hydrogen concentration (BHC) levels during glucose or lactose loading. We have evaluated the usefulness of fasting breath hydrogen concentration (FBHC) measurement without glucose loading for the evaluation of PEI. METHODS: Sixty patients underwent FBHC measurement, BT-PABA testing, and microbiome analysis. They were classified into PEI group (PABA excretion rate < 73.4%, n = 30) and non-PEI group (n = 30). The FBHC of the two groups were compared, and the diagnostic ability of PEI by them was evaluated. The 16 s rRNA (V3-V4) from fecal samples was analyzed by MiSeq. RESULTS: FBHC levels was higher in the PEI group 15.70 (1.4 to 77.0) ppm than in the non-PEI group 2.80 (0.7 to 28.2) ppm (P < 0.0001). FBHC was negatively correlated with PABA excretion rate (r = - 0.523, P < 0.001). The cutoff value of FBHC of 10.7 ppm (95% CI: 0.678-0.913, P < 0.001) showed a sensitivity of 73.3% and specificity of 83.3% for PEI diagnosis. In the PEI group, there was a significant increase of relative abundance of phylum Firmicutes (P < 0.05) and the genus Clostridium (P < 0.05). CONCLUSION: FBHC shows good potential as a simple and repeatable test for the diagnosis of PEI. The elevated FBHC levels may be caused by hydrogen-producing bacteria such as Clostridium.


Assuntos
Insuficiência Pancreática Exócrina , Pancreatopatias , Testes Respiratórios , Insuficiência Pancreática Exócrina/diagnóstico , Jejum , Fezes , Humanos , Hidrogênio
11.
Bioresour Technol ; 335: 125287, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34034065

RESUMO

Biogas upgrading is a necessary step to minimize the CO2 of raw biogas and to make it suitable for gas liquefaction or introduction into the national gas grid. Biomethanation is a promising approach since it converts the CO2 to more methane on site, while taking advantage of the organisms responsible for biogas production in the first place. This study investigates the suitability of a pseudo-dead-end membrane biofilm reactor (MBfR) for ex-situ biogas upgrading using biogas as sole carbon source as well as for additional acetoclastic methanation when an organic carbon source is provided. Results prove that the concept of MBfR is especially advantageous for ex-situ hydrogenotrophic methanation of biogas CO2, yielding high product gas qualities of up to 99% methane. It is discussed that cross-flow membrane operation could reduce mass flux of inert methane through membranes, attached biofilms, and reactor liquid, and, thus, improve methanation space time yields.


Assuntos
Biocombustíveis , Reatores Biológicos , Biofilmes , Carbono , Dióxido de Carbono , Hidrogênio , Metano
12.
Waste Manag ; 129: 20-25, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34020372

RESUMO

A novel approach of using two stage anaerobic digestion coupled with electrodialysis technology has been investigated. This approach was used to improving bio hydrogen and methane yields from food waste while simultaneously producing a green chemical feedstock. The first digester was used for hydrogen production and the second digester was used for methane production. The first digester was combined with continuous separation of volatile fatty acids using electrodialysis. The concentrations of carbohydrates, proteins and fats in the prepared food waste were 22.7%, 5.7% and 5.2% respectively. Continuous removal of volatile fatty acids during fermentation in the hydrogen digester not only increased hydrogen yields but also increased the production rate of volatile fatty acids. As a result of continuous VFA separation, hydrogen yields increased from 17.3 mL H2/g VS fermenter to 33.68 mL H2/g VS fermenter. Methane yields also increased from 28.94 mL CH4/g VS fermenter to 43.94 mL CH4/g VS fermenter. This represents a total increase in bio-energy yields of 77.1%. COD reduced by 73% after using two stage anaerobic digestion, however, this reduction increased to 86.7% after using electrodialysis technology for separation of volatile fatty acids. Electrodialysis technology coupled with anaerobic digestion improved substrate utilization, increased bioenergy yields and looks to be promising for treating complex wastes such as food waste.


Assuntos
Alimentos , Eliminação de Resíduos , Anaerobiose , Reatores Biológicos , Ácidos Graxos Voláteis , Hidrogênio , Metano
13.
Sci Total Environ ; 779: 146463, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34030226

RESUMO

A powerful simple biochar catalyst derived from nanocellulose was applied to the catalytic upcycling of waste plastics into H2 and liquid fuels for the first time. For the results from model low-density polyethylene (LDPE) pyrolysis, the C8-C16 aliphatics and monocyclic aromatics were dominant constitutes of the liquid product with the yields ranging from 22 to 68 wt%. At the temperature of 500 °C and biochar to LDPE ratio surpassing 3, the LDPE could be completely degraded into liquid and gas without wax production. A wax yield of 16 wt% was observed at the temperature of 450 °C and biochar to LDPE ratio of 4, which was dramatically lower than that (77 wt%) from the absence of biochar at the temperature of 500 °C. Up to 92 vol% of H2 was detected in the gaseous product with a yield of 36 wt%. The lower temperatures and higher biochar to LDPE ratios favored increasing the generation of H2 at the expense of light gas CnHm especially CH4. Moreover, this biochar catalyst was tested effectively to convert the real waste plastics including grocery bags and packaging tray into valuable liquid and H2-enriched gas.


Assuntos
Hidrogênio , Plásticos , Catálise , Carvão Vegetal , Pirólise
14.
Sci Total Environ ; 780: 146597, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34030325

RESUMO

The aim of this study was to investigate the performance of single-chamber MEC under applied voltages higher than that for water electrolysis. With different acetate concentrations (1.0-2.0 g/L), the MEC was tested under applied voltages from 0.8 to 2.2 V within 2600 h (54 cycles). Results showed that the MEC was stably operated for the first time within 20 cycles under 2.0 and 2.2 V, compared with the control MEC with significant water electrolysis. The maximum current density reached 27.8 ± 1.4 A/m2 under 2.0 V, which was about three times as that under 0.8 V. The anode potential in the MEC could be kept at 0.832 ± 0.110 V (vs. Ag/AgCl) under 2.2 V, thus without water electrolysis in the MEC. High applied voltage of 1.6 V combined with alkaline solution (pH = 11.2) could result in high hydrogen production and high current density. The maximum current density of MEC at 1.6 V and pH = 11.2 reached 42.0 ± 10.0 A/m2, which was 1.85 times as that at 1.6 V and pH = 7.0. The average hydrogen content reached 97.2% of the total biogas throughout all the cycles, indicating that the methanogenesis was successfully inhibited in the MEC at 1.6 V and pH = 11.2. With high hydrogen production rate and current density, the size and investment of MEC could be significantly reduced under high applied voltages. Our results should be useful for extending the range of applied voltages in the MEC.


Assuntos
Fontes de Energia Bioelétrica , Eletrólise , Acetatos , Biocombustíveis , Eletrodos , Hidrogênio
15.
Waste Manag ; 128: 73-82, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33971379

RESUMO

In this work, a novel method to valorize the polymeric matrix of residual carbon fiber reinforced polymers (CFRP) in the recycling process of carbon fibers by pyrolysis is presented. The experiments have been carried out with an expired epoxy-based pre-preg and in a lab-scale installation composed of two reactors. In the first one, pyrolysis and oxidation have been carried out, while in the second one, the gases and vapors resulting from the thermal decomposition of the polymeric resin have been thermally treated. The following operating parameters have been studied in the pyrolysis step: dwell time, the use of N2 (N2 flow, no N2 flow and not even to inert the reaction medium) and the solid bed material of the second reactor. In the oxidation step, temperature and time have been optimized by using the theory of experiments based on 2 k factorial design was used. It has been demonstrated that clean carbon fibers and a gaseous fraction with 75% by volume of H2 can be obtained. This is possible through a combined process of (1) CFRP thermal decomposition at 500 °C, (2) thermal treatment of gases and vapors at 900 °C in a solid bed tubular reactor filled with a waste refractory material and (3) oxidation of pyrolysis solid at 500 °C during 165 min in presence of 1.3 L air min-1.


Assuntos
Polímeros , Pirólise , Fibra de Carbono , Gases , Hidrogênio , Reciclagem
16.
J Environ Manage ; 291: 112631, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33932835

RESUMO

Energy recovery from lignocellulosic waste has been studied as an alternative to the problem of inappropriate waste disposal. The present study aimed at characterizing the microbial community and the functional activity of reactors applied to H2 production through lignocellulosic waste fermentation in optimized conditions. The latter were identified by means of Rotational Central Composite Design (RCCD), applied to optimize allochthonous inoculum concentration (2.32-5.68 gTVS/L of granular anaerobic sludge), pH (4.32-7.68) and Citrus Peel Waste (CPW) concentration (1.55-28.45 g/L). After validation, the conditions identified for optimal H2 production were 4 gSTV/L of allochthonous inoculum, 29.8 g/L of CPW (substrate) and initial pH of 8.98. In these conditions, 48.47 mmol/L of H2 was obtained, which is 3.64 times higher than the concentration in unoptimized conditions (13.31 mmol H2/L using 15 g/L of CPW, 2 gTVS/L of allochthonous inoculum, pH 7.0). Acetogenesis was the predominant pathway, and maximal concentrations of 3,731 mg/L of butyric acid and 3,516 mg/L of acetic acid were observed. Regarding the metataxonomic profile, Clostridium genus was dramatically favored in the optimized condition (79.78%) when compared to the allochthonous inoculum (0.43%). It was possible to identify several genes related to H2 (i.e dehydrogenases) and volatile fatty acids (VFA) production and with cellulose degradation, especially some CAZymes from the classes Auxiliary Activities, Glycoside Hydrolases and Glycosyl Transferase. By means of differential gene expression it was observed that cellulose degradation and acetic acid production pathways were overabundant in samples from the optimized reactors, highlighting endo-ß-1,4-glucanase/cellulose, endo-ß-1,4-xylanase, ß-glucosidase, ß-mannosidase, cellulose ß-1,4-cellobiosidase, cellobiohydrolase, and others, as main the functions.


Assuntos
Citrus , Anaerobiose , Reatores Biológicos , Ácidos Graxos Voláteis , Fermentação , Hidrogênio/análise , Concentração de Íons de Hidrogênio , Esgotos
17.
Bioresour Technol ; 333: 125217, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33951580

RESUMO

Photobiological hydrogen (H2) production is a promising renewable energy source. HydA hydrogenases of green algae are efficient but O2-sensitive and compete for electrons with CO2-fixation. Recently, we established a photoautotrophic H2 production system based on anaerobic induction, where the Calvin-Benson cycle is inactive and O2 scavenged by an absorbent. Here, we employed thin layer cultures, resulting in a three-fold increase in H2 production relative to bulk CC-124 cultures (50 µg chlorophyll/ml, 350 µmol photons m-2 s-1). Productivity was maintained when increasing the light intensity to 1000 µmol photons m-2s-1 and the cell density to 150 µg chlorophyll/ml. Remarkably, the L159I-N230Y photosystem II mutant and the pgrl1 photosystem I cyclic electron transport mutant produced 50% more H2 than CC-124, while the pgr5 mutant generated 250% more (1.2 ml H2/ml culture in six days). The photosynthetic apparatus of the pgr5 mutant and its in vitro HydA activity remained remarkably stable.


Assuntos
Chlamydomonas reinhardtii , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Hidrogênio/metabolismo , Oxigênio/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema I/metabolismo , Luz Solar
18.
Nat Commun ; 12(1): 3178, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34039963

RESUMO

Living systems formed and evolved under constraints that govern their interactions with the inorganic world. These interactions are definable using basic physico-chemical principles. Here, we formulate a comprehensive set of ten governing abiotic constraints that define possible quantitative metabolomes. We apply these constraints to a metabolic network of Escherichia coli that represents 90% of its metabolome. We show that the quantitative metabolomes allowed by the abiotic constraints are consistent with metabolomic and isotope-labeling data. We find that: (i) abiotic constraints drive the evolution of high-affinity phosphate transporters; (ii) Charge-, hydrogen- and magnesium-related constraints underlie transcriptional regulatory responses to osmotic stress; and (iii) hydrogen-ion and charge imbalance underlie transcriptional regulatory responses to acid stress. Thus, quantifying the constraints that the inorganic world imposes on living systems provides insights into their key characteristics, helps understand the outcomes of evolutionary adaptation, and should be considered as a fundamental part of theoretical biology and for understanding the constraints on evolution.


Assuntos
Adaptação Fisiológica , Escherichia coli/fisiologia , Metaboloma/fisiologia , Estresse Fisiológico , Ácidos/metabolismo , Evolução Biológica , Escherichia coli/química , Proteínas de Escherichia coli/análise , Proteínas de Escherichia coli/metabolismo , Regulação da Expressão Gênica/fisiologia , Hidrogênio/metabolismo , Magnésio/metabolismo , Redes e Vias Metabólicas/fisiologia , Metabolômica , Osmose , Proteínas de Transporte de Fosfato/metabolismo , Fosfatos/metabolismo
19.
Am J Gastroenterol ; 116(4): 780-787, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33982948

RESUMO

INTRODUCTION: The North American Consensus guidelines for glucose breath testing (GBT) for small intestinal bacterial overgrowth (SIBO) incorporated changes in glucose dosing and diagnostic cutoffs. We compared GBT positivity based on hydrogen and methane excretion and quantified symptoms during performance of the North American vs older modified Rome Consensus protocols. METHODS: GBT was performed using the North American protocol (75 g glucose, cutoffs >20 parts per million [ppm] hydrogen increase after glucose and >10 ppm methane anytime) in 3,102 patients vs modified Rome protocol (50 g glucose, >12 ppm hydrogen and methane increases after glucose) in 3,193 patients with suspected SIBO. RESULTS: Positive GBT were more common with the North American vs modified Rome protocol (39.5% vs 29.7%, P < 0.001). Overall percentages with GBT positivity using methane criteria were greater and hydrogen criteria lower with the North American protocol (P < 0.001). Peak methane levels were higher for the North American protocol (P < 0.001). Times to peak hydrogen and methane production were not different between protocols. With the North American protocol, gastrointestinal and extraintestinal symptoms were more prevalent after glucose with both positive and negative GBT (P < 0.04) and greater numbers of symptoms (P < 0.001) were reported. DISCUSSION: GBT performed using the North American Consensus protocol was more often positive for SIBO vs the modified Rome protocol because of more prevalent positive methane excretion. Symptoms during testing were greater with the North American protocol. Implications of these observations on determining breath test positivity and antibiotic decisions for SIBO await future prospective testing.


Assuntos
Infecções Bacterianas/diagnóstico , Testes Respiratórios/métodos , Consenso , Glucose/farmacologia , Enteropatias/diagnóstico , Intestino Delgado/microbiologia , Infecções Bacterianas/metabolismo , Infecções Bacterianas/microbiologia , Feminino , Humanos , Hidrogênio/análise , Enteropatias/metabolismo , Enteropatias/microbiologia , Masculino , Metano/análise , Pessoa de Meia-Idade , Estudos Retrospectivos
20.
Nutrients ; 13(4)2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33919766

RESUMO

Many patients with inflammatory bowel disease (IBD) restrict dairy products to control their symptoms. The aim of the study was to investigate the prevalence of lactose intolerance assessed with hydrogen breath test (H-BT) in IBD patients in clinical remission compared to a sex, age and BMI matched control population. We further detected the prevalence of three single nucleotide polymorphisms of the lactase (LCT) gene: the lactase non persistence LCT-13910 CC (wildtype) and the intermediate phenotype LCT-22018 CT and LCT-13910 AG; finally, we assess the correlation between genotype and H-BT. A total of 54 IBD patients and 69 control who underwent clinical evaluation, H-BT and genetic test were enrolled. H-BT was positive in 64.8% IBD patients and 62.3% control (p = 0.3). The wild-type genotype was found in 85.2% IBD patients while CT-22018, AG-13910 and CT-22018/AG-13910 polymorphisms were found in 9.3%, 1.8% and 3.7%. In the control group, the wild-type genotype, CT-22018, AG-13910 and CT-22018/AG-13910 polymorphisms were found in 87%, 5.8%, 5.8% and 1.4% of cases, respectively. Therefore, the wild-type and polymorphisms' prevalence did not differ between IBD population and control group (85.2% vs. 87%, p = 0.1) (14.8% vs. 13%, p = 0.7). The correlation between positive H-BT and genetic analysis showed that the wild-type genotype was associated with higher rate of lactose intolerance in the total population (OR 5.31, 95%CI 1.73-16.29, p = 0.003) and in the IBD (OR 7.61, 95%CI 1.36-42.7, p = 0.02). The prevalence of lactose intolerance in IBD patients did not differ from that of control. Despite suggestive symptoms, about 1/3 of IBD patients are not lactose intolerant, thus not needing "a priori" elimination diet. This may encourage a rationale and balanced dietary management in IBD.


Assuntos
Doenças Inflamatórias Intestinais/dietoterapia , Lactase/genética , Intolerância à Lactose/epidemiologia , Lactose/efeitos adversos , Adulto , Testes Respiratórios/métodos , Testes Genéticos/estatística & dados numéricos , Humanos , Hidrogênio/análise , Doenças Inflamatórias Intestinais/complicações , Lactase/metabolismo , Lactose/metabolismo , Intolerância à Lactose/complicações , Intolerância à Lactose/diagnóstico , Intolerância à Lactose/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Prevalência , Estudos Prospectivos , Adulto Jovem
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