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1.
Biomed Environ Sci ; 33(8): 566-572, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32933608

RESUMO

Objective: This study aimed to measure the basal energy expenditure (BEE) of Chinese healthy adults and establish an accurate predictive equation for this population. Methods: In total, 470 Chinese healthy adults had their BEE measured using the Cosmed K4b 2 portable metabolic system. Multiple linear regression analysis was applied to develop new optimal equations for predicting BEE. The bias, accuracy rate, concordance correlation coefficient (CCC), and root mean square error (RMSE) were used to evaluate the accuracy of the predictive equations. Results: There was a significant difference in BEE between males and females, with 5,954 kJ/d and 5,089 kJ/d, respectively. People living in rural areas expended significantly higher BEE (5,885 kJ/d) than those in urban areas (5,279 kJ/d). Previous equations developed by Henry, Schofield, Harris-Benedict (H-B), and Liu overestimated the BEE of Chinese healthy adults. The new equations derived from the present study displayed the smallest average bias and RMSE from the measured basal energy expenditure (mBEE). The CCC of the new equations was higher than other predictive equations, but it was lower than 0.8. There was no significant difference in the accuracy rate among all predictive equations. Conclusions: Sex and regional differences in BEE were observed in Chinese healthy adults. Neither the widely used previous predictive equations nor the one derived in the present study were accurate enough for estimating the BEE of Chinese healthy adults. Further study is required to develop more accurate equations for predicting the BEE of Chinese healthy adults aged between 20-45 years.


Assuntos
Metabolismo Basal , Calorimetria/métodos , Adulto , China , Feminino , Humanos , Masculino , Adulto Jovem
2.
Nat Commun ; 11(1): 4115, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807795

RESUMO

The transcription factor STAT3 is frequently activated in human solid and hematological malignancies and remains a challenging therapeutic target with no approved drugs to date. Here, we develop synthetic antibody mimetics, termed monobodies, to interfere with STAT3 signaling. These monobodies are highly selective for STAT3 and bind with nanomolar affinity to the N-terminal and coiled-coil domains. Interactome analysis detects no significant binding to other STATs or additional off-target proteins, confirming their exquisite specificity. Intracellular expression of monobodies fused to VHL, an E3 ubiquitin ligase substrate receptor, results in degradation of endogenous STAT3. The crystal structure of STAT3 in complex with monobody MS3-6 reveals bending of the coiled-coil domain, resulting in diminished DNA binding and nuclear translocation. MS3-6 expression strongly inhibits STAT3-dependent transcriptional activation and disrupts STAT3 interaction with the IL-22 receptor. Therefore, our study establishes innovative tools to interfere with STAT3 signaling by different molecular mechanisms.


Assuntos
Anticorpos/metabolismo , Fator de Transcrição STAT3/metabolismo , Células A549 , Anticorpos/genética , Western Blotting , Calorimetria , Cristalografia por Raios X , Citometria de Fluxo , Polarização de Fluorescência , Imunofluorescência , Humanos , Espectrometria de Massas , Ligação Proteica , Domínios Proteicos/imunologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/imunologia , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Biologia Sintética
3.
Nat Commun ; 11(1): 3464, 2020 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32651375

RESUMO

DOCK (dedicator of cytokinesis) proteins are multidomain guanine nucleotide exchange factors (GEFs) for RHO GTPases that regulate intracellular actin dynamics. DOCK proteins share catalytic (DOCKDHR2) and membrane-associated (DOCKDHR1) domains. The structurally-related DOCK1 and DOCK2 GEFs are specific for RAC, and require ELMO (engulfment and cell motility) proteins for function. The N-terminal RAS-binding domain (RBD) of ELMO (ELMORBD) interacts with RHOG to modulate DOCK1/2 activity. Here, we determine the cryo-EM structures of DOCK2-ELMO1 alone, and as a ternary complex with RAC1, together with the crystal structure of a RHOG-ELMO2RBD complex. The binary DOCK2-ELMO1 complex adopts a closed, auto-inhibited conformation. Relief of auto-inhibition to an active, open state, due to a conformational change of the ELMO1 subunit, exposes binding sites for RAC1 on DOCK2DHR2, and RHOG and BAI GPCRs on ELMO1. Our structure explains how up-stream effectors, including DOCK2 and ELMO1 phosphorylation, destabilise the auto-inhibited state to promote an active GEF.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Calorimetria , Proteínas Ativadoras de GTPase/genética , Fatores de Troca do Nucleotídeo Guanina/genética , Células HEK293 , Células HeLa , Humanos , Immunoblotting , Cinética , Microscopia Eletrônica , Fosforilação , Proteínas rac1 de Ligação ao GTP/genética , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas rho de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/metabolismo
4.
Food Chem ; 333: 127514, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32683259

RESUMO

This study investigated the effect of pH on the denaturation extent, the surface chemical composition, the water sorption isotherm and the glass transition temperature of camel and bovine whey protein's powders. The LC-MS analysis indicated that the ß-Lactoglobulin was the most denatured protein in bovine whey powders regardless the pH value, while this protein was totally absent in camel whey. The α-Lactalbumin was relatively heat stable after drying and predominated the powder surface (X-ray photoelectron spectroscopy results) in both camel and bovine whey powders regardless the pH (neutral (6.7) or acidic (4.3 and 4.6)). Analysis of the water sorption isotherms indicated that decreasing the pH induced the increase of the water activity of lactose crystallization for camel and bovine whey powders. Finally, decreasing the pH led to the decrease of the glass transition temperature of camel and bovine whey powder (at 0.13, 0.23, and 0.33 of water activity).


Assuntos
Pós/química , Proteínas do Soro do Leite/química , Adsorção , Animais , Calorimetria , Camelus , Bovinos , Cromatografia Líquida de Alta Pressão , Cristalização , Concentração de Íons de Hidrogênio , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Lactose/química , Espectrometria de Massas , Desnaturação Proteica , Propriedades de Superfície , Temperatura de Transição , Água/química , Proteínas do Soro do Leite/metabolismo
5.
Int J Nanomedicine ; 15: 3393-3404, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32523339

RESUMO

Introduction: The efficacy of several antimicrobial agents has been hindered due to the increasing frequency of multidrug-resistant (MDR) Pseudomonas aeruginosa strains. So, the need for new antibacterial drugs or drug combinations is urgent. Recently, desirable antibacterial effects were reported for many metals nanoparticles such as TiO2 nanoparticles (TDNs). Purpose: This study aims to investigate the prevalence of MDR P. aeruginosa and assess the efficiency of TDN in the treatment of MDR P. aeruginosa-associated infections. Materials and Methods: The synthesis of TDN by the sol-gel method was carried out. Particle size measurements and morphology were done using dynamic light scattering (DLS) and high-resolution transmission electron microscopy (HR-TEM). To investigate the physical and chemical changes of drugs due to the combination, the tested drugs, both alone and in combination with TDN, were subjected to differential scanning calorimetry (DSC), infrared (IR) spectroscopy, and X-ray diffraction studies. Antimicrobial susceptibility was detected by agar disc-diffusion assay. The minimum inhibitory concentration (MIC) of TDN and the tested antibiotics were assessed by the agar dilution method. Checkerboard analysis was performed to determine the combined effect of TDN and the tested antibiotics against 25 MDR P. aeruginosa strains. Results: TDNs were prepared with an average particle size of 64.77 ± 0.14 nm with an accepted polydispersity index (PDI) value of 0.274 ± 0.004. TEM showed that the particles were shaped into irregular spheres. Twenty-five P. aeruginosa isolates that were absolutely resistant to cefepime (100%), highly resistant to ceftriaxone (96%), amikacin (80%), and ciprofloxacin (76%) were selected. Superior antibacterial activity of TDN was observed against the selected 25 MDR P. aeruginosa isolates. The combination of TDN and cefepime were found to show synergistic activity against all tested isolates followed by ceftriaxone (96%), amikacin (88%), and ciprofloxacin (80%). Conclusion: Using TDN in combination with antibiotics can help in the treatment of MDR P. aeruginosa-associated infections. So, preparation of topical pharmaceutical dosage forms containing a combination of these antibiotics and TDN can be useful against MDR P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Nanopartículas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Titânio/farmacologia , Antibacterianos/uso terapêutico , Calorimetria , Ciprofloxacino/farmacologia , Ciprofloxacino/uso terapêutico , Humanos , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Tamanho da Partícula , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/isolamento & purificação , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
Nat Commun ; 11(1): 2983, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32532993

RESUMO

Calorimetry has been widely used in metabolic studies, but direct measurements from individual small biological model organisms such as C. elegans or isolated single cells have been limited by poor sensitivity of existing techniques and difficulties in resolving very small heat outputs. Here, by careful thermal engineering, we developed a robust, highly sensitive and bio-compatible calorimetric platform that features a resolution of ~270 pW-more than a 500-fold improvement over the most sensitive calorimeter previously used for measuring the metabolic heat output of C. elegans. Using this calorimeter, we demonstrate time-resolved metabolic measurements of single C. elegans worms from larval to adult stages. Further, we show that the metabolic output is significantly lower in long-lived C. elegans daf-2 mutants. These demonstrations clearly highlight the broad potential of this tool for studying the role of metabolism in disease, development and aging of small model organisms and single cells.


Assuntos
Caenorhabditis elegans/metabolismo , Calorimetria/métodos , Análise de Célula Única/métodos , Temperatura , Animais , Metabolismo Basal/genética , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Calorimetria/instrumentação , Metabolismo Energético/genética , Humanos , Larva/citologia , Larva/genética , Larva/metabolismo , Longevidade/genética , Modelos Animais , Mutação , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Reprodutibilidade dos Testes , Análise de Célula Única/instrumentação , Condutividade Térmica
7.
Nat Commun ; 11(1): 2982, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32532969

RESUMO

Non-invasive and label-free calorimetry could become a disruptive technique to study single cell metabolic heat production without altering the cell behavior, but it is currently limited by insufficient sensitivity. Here, we demonstrate microfluidic single-cell calorimetry with 0.2-nW sensitivity, representing more than ten-fold enhancement over previous record, which is enabled by (i) a low-noise thermometry platform with ultralow long-term (10-h) temperature noise (80 µK) and (ii) a microfluidic channel-in-vacuum design allowing cell flow and nutrient delivery while maintaining a low thermal conductance of 2.5 µW K-1. Using Tetrahymena thermophila as an example, we demonstrate on-chip single-cell calorimetry measurement with metabolic heat rates ranging from 1 to 4 nW, which are found to correlate well with the cell size. Finally, we perform real-time monitoring of metabolic rate stimulation by introducing a mitochondrial uncoupling agent to the microchannel, enabling determination of the spare respiratory capacity of the cells.


Assuntos
Calorimetria/métodos , Técnicas Analíticas Microfluídicas/métodos , Microfluídica/métodos , Análise de Célula Única/métodos , Temperatura , Tetrahymena thermophila/metabolismo , Metabolismo Basal , Calorimetria/instrumentação , Microfluídica/instrumentação , Mitocôndrias/metabolismo , Consumo de Oxigênio , Análise de Célula Única/instrumentação , Tetrahymena thermophila/citologia , Condutividade Térmica
8.
Environ Sci Pollut Res Int ; 27(29): 36639-36650, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32564314

RESUMO

This work proposes a new methodology to determine the adsorption mechanism for salicylic acid and paracetamol on activated carbon based on the physicochemical characteristics of adsorbent and adsorbates. The methodology is divided into two parts: the determination of adsorption kinetics (order and mechanism) and the study of the chemical interactions (adsorbate-adsorbent and solvent-adsorbent) using calorimetry tests. Then, the results obtained in both techniques were correlated with the amount of drug adsorbed. The adsorption kinetics of salicylic acid and paracetamol on activated carbons with different oxygen contents could be described with widely kinetic models such as intraparticle, pseudo-first-order, pseudo-second-order, Avrami, and Elovich models; different information about the adsorption mechanism are offered by each of them. The results indicated that the pseudo-first-order rate constant decreases with the molecular size of analgesics and the carboxylic acid groups on the adsorbent surface; the rate constant values are between 0.12 and 2.31 h-1. The adsorbed amount of analgesics and the adsorption rate are greatest on activated carbons with basic characteristics (QRAC 0.45 > 0.24 > 0.21 mmol g-1 for phenol, salicylic acid, and paracetamol, respectively). The enthalpy changes follow the same trend in all activated carbons; for RAC, the results were ΔHimmPHEN = - 33.4 J g-1, ΔHimmSA = - 35.9 J g-1, and ΔHimmPAR = - 45.4 J g-1. The analgesic diffusion rate in the boundary layer increases with the formation of adsorbate-adsorbent interactions (exothermic process).


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Analgésicos , Calorimetria , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica
9.
Food Chem ; 331: 127337, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32585547

RESUMO

Naringenin (NG) is a flavonoid with many bioactive properties, however, its bitterness limits its use in foods. It is known that complex formation with proteins can mask this undesirable sensory property. Therefore, a trained panel evaluated the effect of bovine lactoferrin (LF) on NG bitterness using time-intensity analysis. LF reduced the maximum bitterness intensity and overall bitterness perception for NG by 27% and 33%, respectively. Isothermal titration nanocalorimetry (ITC), molecular docking (DC), and molecular dynamics (MD) were used to characterize NG-LF binding. These techniques provided similar values of ΔG° for binding ( [Formula: see text]  = -33.42 kJ mol-1; [Formula: see text]  = -32.22 kJ mol-1; [Formula: see text]  = -31.84 kJ mol-1). ITC showed that the complex formation is primarily entropy driven and DC suggested that NG binds at a hydrophobic site in LF. Here are presented strategic tools for promoting NG incorporation in food and health products.


Assuntos
Flavanonas/metabolismo , Flavanonas/farmacologia , Lactoferrina/química , Lactoferrina/metabolismo , Paladar , Adulto , Animais , Calorimetria/métodos , Bovinos , Entropia , Feminino , Flavanonas/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Masculino , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Termodinâmica
10.
Food Chem ; 329: 127219, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516714

RESUMO

Plant-based proteins and polyphenols are increasingly being explored as functional food ingredients. Colloidal complexes were prepared from pea protein (PP) and grape seed proanthocyanidin (GSP) and the ability of the PP/GSP complexes to form and stabilize oil-in-water emulsions were investigated. The main interactions between PP and GSP were hydrogen bonding. The stability of PP-GSP complexes to environmental changes were studied: pH (2-9); ion strength (0-0.3 M); and temperature (30-90 °C). Emulsions produced using PP-GSP complexes as emulsifiers had small mean droplet diameters (~200 nm) and strongly negative surface potentials (~-60 mV). Compared to PP alone, PP-GSP complexes slightly decreased the isoelectric point, thermostability, and salt stability of the emulsions, but increased their storage stability. The presence of GSP gave the emulsions a strong salmon (red-yellow) color, which may be beneficial for some specific applications. These results may assist in the creation of more efficacious food-based strategies for delivering proanthocyanidins.


Assuntos
Emulsões/química , Extrato de Sementes de Uva/química , Proteínas de Ervilha/química , Ervilhas/metabolismo , Polifenóis/química , Proantocianidinas/química , Antioxidantes/química , Sítios de Ligação , Calorimetria , Extrato de Sementes de Uva/metabolismo , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Simulação de Acoplamento Molecular , Óleos/química , Concentração Osmolar , Proteínas de Ervilha/metabolismo , Polifenóis/metabolismo , Proantocianidinas/metabolismo , Cloreto de Sódio/química , Temperatura , Água/química
11.
Nat Commun ; 11(1): 2303, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385276

RESUMO

White adipose tissue (WAT) expansion in obesity occurs through enlargement of preexisting adipocytes (hypertrophy) and through formation of new adipocytes (adipogenesis). Adipogenesis results in WAT hyperplasia, smaller adipocytes and a metabolically more favourable form of obesity. How obesogenic WAT hyperplasia is induced remains, however, poorly understood. Here, we show that the mechanosensitive cationic channel Piezo1 mediates diet-induced adipogenesis. Mice lacking Piezo1 in mature adipocytes demonstrated defective differentiation of preadipocyte into mature adipocytes when fed a high fat diet (HFD) resulting in larger adipocytes, increased WAT inflammation and reduced insulin sensitivity. Opening of Piezo1 in mature adipocytes causes the release of the adipogenic fibroblast growth factor 1 (FGF1), which induces adipocyte precursor differentiation through activation of the FGF-receptor-1. These data identify a central feed-back mechanism by which mature adipocytes control adipogenesis during the development of obesity and suggest Piezo1-mediated adipocyte mechano-signalling as a mechanism to modulate obesity and its metabolic consequences.


Assuntos
Adipócitos/metabolismo , Fator 1 de Crescimento de Fibroblastos/metabolismo , Canais Iônicos/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Adipogenia/fisiologia , Tecido Adiposo Branco/metabolismo , Animais , Calorimetria , Células Cultivadas , Feminino , Fator 1 de Crescimento de Fibroblastos/genética , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Insulina/sangue , Interleucina-6/sangue , Canais Iônicos/genética , Masculino , Camundongos , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
12.
Nat Commun ; 11(1): 2148, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358497

RESUMO

Hyperglycemia activates toll-like receptor 4 (TLR4) to induce inflammation in diabetic cardiomyopathy (DCM). However, the mechanisms of TLR4 activation remain unclear. Here we examine the role of myeloid differentiation 2 (MD2), a co-receptor of TLR4, in high glucose (HG)- and diabetes-induced inflammatory cardiomyopathy. We show increased MD2 in heart tissues of diabetic mice and serum of human diabetic subjects. MD2 deficiency in mice inhibits TLR4 pathway activation, which correlates with reduced myocardial remodeling and improved cardiac function. Mechanistically, we show that HG induces extracellular advanced glycation end products (AGEs), which bind directly to MD2, leading to formation of AGEs-MD2-TLR4 complex and initiation of pro-inflammatory pathways. We further detect elevated AGE-MD2 complexes in heart tissues and serum of diabetic mice and human subjects with DCM. In summary, we uncover a new mechanism of HG-induced inflammatory responses and myocardial injury, in which AGE products directly bind MD2 to drive inflammatory DCM.


Assuntos
Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/metabolismo , Cardiomiopatias Diabéticas/imunologia , Cardiomiopatias Diabéticas/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Animais , Western Blotting , Calorimetria , Linhagem Celular , Humanos , Imunoprecipitação , Antígeno 96 de Linfócito/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Receptor 4 Toll-Like/metabolismo
13.
Arch Biochem Biophys ; 688: 108401, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32376316

RESUMO

HIV-1 glycoprotein 41 (gp41) mediates fusion between virus and target cells by folding into a fusion active state, in which the C-terminal heptad repeat (CHR) regions associate externally to the N-terminal heptad repeat (NHR) trimer and form a very stable six-helix bundle coiled-coil structure. Therefore, interfering with the NHR-CHR interaction of gp41 is a promising therapeutic approach against HIV-1. However, a full understanding of the molecular and mechanistic details of this interaction is still incomplete. Here, we use single-chain, chimeric proteins (named covNHR) that reproduce accurately the CHR-NHR interactions to analyze the binding thermodynamics of several peptides with different length from the CHR region. The results indicate that cooperative binding involving two or more pockets of the NHR groove is necessary to obtain relevant affinities and that the binding energy is broadly distributed along the interface, underlining a crucial role of a middle pocket to achieve tight binding. In contrast, targeting only the deep hydrophobic pocket is insufficient to achieve significant affinity. Moreover, calorimetry experiments in combination with limited proteolysis performed using a mutant with occluded binding in the N-terminal pocket reveal the existence of an allosteric communication between the different regions. This study is the first detailed thermodynamic dissection of the NHR-CHR interaction in gp41 and contributes therefore to a better understanding of HIV fusion. These results are relevant for the development of potential fusion inhibitors.


Assuntos
Proteína gp41 do Envelope de HIV/metabolismo , HIV-1/química , Fragmentos de Peptídeos/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Calorimetria , Proteína gp41 do Envelope de HIV/química , Fragmentos de Peptídeos/química , Ligação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Termodinâmica
14.
Food Chem ; 321: 126750, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32278273

RESUMO

This work investigated the interaction between cyclodextrins and pullulanase to provide insight into the production and application of cyclodextrins. Enzyme activity and kinetic assays showed that α-cyclodextrin (α-CD), ß-cyclodextrin (ß-CD) and γ-cyclodextrin (γ-CD) inhibited pullulanase in a competitive manner. Circular dichroism spectra and fluorescence spectroscopy suggested the formation of cyclodextrin and pullulanase complexes. According to ITC assays and molecular docking results, compared with α-CD and γ-CD, ß-CD had the strongest affinity for pullulanase because of its appropriate cavity geometric dimensions. In addition, cyclodextrins interacted with pullulanase through hydrogen bonds, van der Waals force and hydrophobic interactions, the latter of which were verified as the major driving force. Phenylalanine 476 was the key amino acid residue in pullulanase for cyclodextrin recognition and binding.


Assuntos
Ciclodextrinas/química , Ciclodextrinas/metabolismo , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Calorimetria/métodos , Dicroísmo Circular , Glicosídeo Hidrolases/antagonistas & inibidores , Ligação de Hidrogênio , Simulação de Acoplamento Molecular , Fenilalanina/metabolismo , Estrutura Secundária de Proteína , Espectrometria de Fluorescência , alfa-Ciclodextrinas/química , alfa-Ciclodextrinas/metabolismo , beta-Ciclodextrinas/química , beta-Ciclodextrinas/metabolismo , gama-Ciclodextrinas/química , gama-Ciclodextrinas/metabolismo
15.
Food Chem ; 322: 126709, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283376

RESUMO

This study elucidated the formation mechanism of calcium-indigo carmine (IC) complex. Parameters of the complex, such as Turbiscan stability index (TSI), yield and stoichiometric ratio (Ca to IC) were investigated. Isothermal titration calorimetry (ITC), UV/Visible spectrophotometry, infrared spectroscopy and Raman spectroscopy were used to explore the interaction between IC and Ca(II) during formation reaction and in the powdered lake. The TSI analysis and yield test suggested pH 7.0 as the most suitable pH to produce this complex. The conjugation between IC and Ca(II) was an exothermal reaction with increase of entropy (ΔH = -0.728 ± 0.11 kJ·mol-1 and ΔS = 66.55 ± 1.89 kJ·mol-1·K-1 at 25 °C). Both ITC and stoichiometric ratio test suggested one Ca atom tended to conjugate five IC molecules at ambient temperature when an adequate amount of Ca(II) appeared. Spectrometry techniques suggested that the sulfonic acid groups in IC formed coordination bonds with the Ca to construct the complex.


Assuntos
Cálcio/química , Corantes de Alimentos/química , Índigo Carmim/química , Calorimetria , Cor , Entropia , Espectrofotometria , Espectrofotometria Infravermelho
16.
Bull Environ Contam Toxicol ; 104(6): 864-870, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32342111

RESUMO

Fraxinellone is an important botanical lactone compound and has been demonstrated to have insecticidal activity. To provide theoretical support to the assessment on the safety of utilizing fraxinellone as a natural insecticidal agent, the interactions between fraxinellone and armyworm DNA, salmon sperm DNA and calf thymus DNA were investigated using UV-Vis absorption spectroscopy, isothermal titration calorimetry, and molecular docking. Results showed that there were two types of combinations between fraxinellone and three kinds of DNA. Type I combination had an equilibrium constant of combination (Ka1) of about 105 and binding sites (n1) of 0.40-0.70, while type II combination had an equilibrium constant of combination (Ka2) of 103 and binding sites (n2) of 1.35-3.15. Results of molecular docking showed that there were non-classical embedding type interactions between fraxinellone and three kinds of DNA, with the reaction taking place in small groove areas of the DNA structure, resulting in relatively weak interactive forces.


Assuntos
Benzofuranos/química , Agentes de Controle Biológico/química , DNA/química , Inseticidas/química , Animais , Calorimetria , Simulação de Acoplamento Molecular , Mariposas/efeitos dos fármacos , Análise Espectral , Termodinâmica
17.
PLoS One ; 15(4): e0231389, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267888

RESUMO

The diagnosis of implant-associated infections is hampered due to microbial adherence and biofilm formation on the implant surface. Sonication of explanted devices was shown to improve the microbiological diagnosis by physical removal of biofilms. Recently, chemical agents have been investigated for biofilm dislodgement such as the chelating agent ethylenediaminetetraacetic acid (EDTA) and the reducing agent dithiothreitol (DTT). We compared the activity of chemical methods for biofilm dislodgement to sonication in an established in vitro model of artificial biofilm. Biofilm-producing laboratory strains of Staphylococcus epidermidis (ATCC 35984), S. aureus (ATCC 43300), E. coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 53278) were used. After 3 days of biofilm formation, porous glass beads were exposed to control (0.9% NaCl), sonication or chemical agents. Quantitative and qualitative biofilm analyses were performed by colony counting, isothermal microcalorimetry and scanning electron microscopy. Recovered colony counts after treatment with EDTA and DTT were similar to those after exposure to 0.9% NaCl for biofilms of S. epidermidis (6.3 and 6.1 vs. 6.0 log10 CFU/mL, S. aureus (6.4 and 6.3 vs. 6.3 log10 CFU/mL), E. coli (5.2 and 5.1 vs. 5.1 log10 CFU/mL and P. aeruginosa (5.1 and 5.2 vs. 5.0 log10 CFU/mL, respectively). In contrast, with sonication higher CFU counts were detected with all tested microorganisms (7.5, 7.3, 6.2 and 6.5 log10 CFU/mL, respectively) (p <0.05). Concordant results were observed with isothermal microcalorimetry and scanning electron microscopy. In conclusion, sonication is superior to both tested chemical methods (EDTA and DTT) for dislodgement of S. epidermidis, S. aureus, E. coli and P. aeruginosa biofilms. Future studies may evaluate potential additive effect of chemical dislodgement to sonication.


Assuntos
Bactérias/isolamento & purificação , Biofilmes/efeitos dos fármacos , Quelantes/farmacologia , Infecções Relacionadas à Prótese/diagnóstico , Substâncias Redutoras/farmacologia , Sonicação , Bactérias/efeitos dos fármacos , Carga Bacteriana/métodos , Calorimetria , Ditiotreitol/farmacologia , Ácido Edético/farmacologia , Escherichia coli/isolamento & purificação , Escherichia coli/fisiologia , Humanos , Microscopia Eletrônica de Varredura , Infecções Relacionadas à Prótese/microbiologia , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas aeruginosa/fisiologia , Substâncias Redutoras/química , Cloreto de Sódio/farmacologia , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/fisiologia , Staphylococcus epidermidis/isolamento & purificação , Staphylococcus epidermidis/fisiologia
18.
J Clin Neurosci ; 75: 188-194, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32223973

RESUMO

BACKGROUND: Alzheimer's Disease (AD) is the most common form of dementia seen in advanced age. It is characterized by progressive deterioration in cognitive functions. The prevalence of Alzheimer's disease increasing day by day due to the increase in the share of the elderly population in the general population due to developing health and living conditions, is limited and early diagnosis and effective treatment possibilities are very limited. From this point of view, a specific biomarker for AD is very important. As a new oxidative stress biomarker, the levels of thiol-disulfide balance, ischemia-modified albumin and seroloplazminin were evaluated. The aim of this study was to determine the serum levels of oxidative stress biomarkers in the early stages of the disease and to compare these oxidative stress markers with patients with mild cognitive impairment as a precursor form of Alzheimer's disease and to determine whether these markers develop at an earlier stage. METHODS: 30 volunteers with early stage AD according to NINCDS-ARDRA criteria, 19 volunteers with Midl Cognitive Impairment according to PCA criteria and 30 volunteers with defined criteria were selected from the subjects aged between 55 and 88 who applied to Gazi University Health Research. Statistical analysis of the data showed that there was a significant difference between the endgroups and biomarkers for the early diagnosis of Alzheimer's disease, but this complicated matter has to be investigated in more comprehensive and detailed studie. RESULTS: In the present study, we investigated oxidative stress parameters, thiol-disulphide balance, ischemia modified abumin and seruloplasmin in parallel with the impairment in cognitive dysfunction from control group to Mild Cognitive Impairment (MCD) and AD group by using a newly-developed method. CONCLUSIONS: This is the first study in literature comparing Early Stages Alzheimer Disease (ESAD), MCD and healthy volunteer groups. Our study has revealed that these newly developed tests may be candidates as oxidative stress biomarkers in pathgenesis of AD. However it was concluded that more comprehensive and detailed studies are required to enlighten this issue.


Assuntos
Doença de Alzheimer/sangue , Disfunção Cognitiva/sangue , Estresse Oxidativo/fisiologia , Compostos de Sulfidrila/sangue , Sulfitos/sangue , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Biomarcadores/sangue , Calorimetria/métodos , Cognição/fisiologia , Disfunção Cognitiva/diagnóstico , Diagnóstico Precoce , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Albumina Sérica Humana
19.
Proc Natl Acad Sci U S A ; 117(15): 8486-8493, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32234785

RESUMO

Nucleic acid aptamers hold great promise for therapeutic applications due to their favorable intrinsic properties, as well as high-throughput experimental selection techniques. Despite the utility of the systematic evolution of ligands by the exponential enrichment (SELEX) method for aptamer determination, complementary in silico aptamer design is highly sought after to facilitate virtual screening and increased understanding of important nucleic acid-protein interactions. Here, with a combined experimental and theoretical approach, we have developed two optimal epithelial cellular adhesion molecule (EpCAM) aptamers. Our structure-based in silico method first predicts their binding modes and then optimizes them for EpCAM with molecular dynamics simulations, docking, and free energy calculations. Our isothermal titration calorimetry experiments further confirm that the EpCAM aptamers indeed exhibit enhanced affinity over a previously patented nanomolar aptamer, EP23. Moreover, our study suggests that EP23 and the de novo designed aptamers primarily bind to EpCAM dimers (and not monomers, as hypothesized in previous published works), suggesting a paradigm for developing EpCAM-targeted therapies.


Assuntos
Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Molécula de Adesão da Célula Epitelial/química , Molécula de Adesão da Célula Epitelial/metabolismo , Magnésio/metabolismo , Calorimetria , Cristalografia por Raios X , Humanos , Ligantes , Modelos Moleculares , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , Conformação Proteica , Multimerização Proteica , Técnica de Seleção de Aptâmeros
20.
PLoS One ; 15(3): e0229738, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160222

RESUMO

Ultrasound has many uses, such as in medical imaging, monitoring of crystallization, characterization of emulsions and suspensions, and disruption of cell membranes in the food industry. It can also affect microbial cells by promoting or slowing their growth and increasing the production of some metabolites. However, the exact mechanism explaining the effect of ultrasound has not been identified yet. Most equipment employed to study the effect of ultrasound on microorganisms has been designed for other applications and then only slightly modified. This results in limited control over ultrasound frequency and input power, or pressure distribution in the reactor. The present study aimed to obtain a well-defined reactor by simulating the pressure distribution of a sonobioreactor. Specifically, we optimized a sonotrode to match the bottle frequency and compared it to measured results to verify the accuracy of the simulation. The measured pressure distribution spectrum presented the same overall trend as the simulated spectrum. However, the peaks were much less intense, likely due to non-linear events such as the collapse of cavitation bubbles. To test the application of the sonobioreactor in biological systems, two biotechnologically interesting microorganisms were assessed: an electroactive bacterium, Geobacter sulfurreducens, and a lignocellulose-degrading fungus, Fusarium oxysporum. Sonication resulted in increased malate production by G. sulfurreducens, but no major effect on growth. In comparison, morphology and growth of F. oxysporum were more sensitive to ultrasound intensity. Despite considerable morphological changes at 4 W input power, the growth rate was not adversely affected; however, at 12 W, growth was nearly halted. The above findings indicate that the novel sonobioreactor provides an effective tool for studying the impact of ultrasound on microorganisms.


Assuntos
Reatores Biológicos/microbiologia , Fusarium/crescimento & desenvolvimento , Geobacter/crescimento & desenvolvimento , Análise Numérica Assistida por Computador , Sonicação , Calorimetria , Simulação por Computador , Fusarium/ultraestrutura , Geobacter/metabolismo , Malatos/metabolismo , Metaboloma , Pressão , Vibração
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