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1.
Molecules ; 26(4)2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33673047

RESUMO

The analysis of stability of biologically active compounds requires an accurate determination of their structure. We have found that 5-aryl-3-(2-aminoethyl)-1,2,4-oxadiazoles are generally unstable in the presence of acids and bases and are rearranged into the salts of spiropyrazolinium compounds. Hence, there is a significant probability that it is the rearranged products that should be attributed to biological activity and not the primarily screened 5-aryl-3-(2-aminoethyl)-1,2,4-oxadiazoles. A series of the 2-amino-8-oxa-1,5-diazaspiro[4.5]dec-1-en-5-ium (spiropyrazoline) benzoates and chloride was synthesized by Boulton-Katritzky rearrangement of 5-substituted phenyl-3-[2-(morpholin-1-yl)ethyl]-1,2,4-oxadiazoles and characterized using FT-IR and NMR spectroscopy and X-ray diffraction. Spiropyrazolylammonium chloride demonstrates in vitro antitubercular activity on DS (drug-sensitive) and MDR (multidrug-resistant) of MTB (M. tuberculosis) strains (1 and 2 µg/mL, accordingly) equal to the activity of the basic antitubercular drug rifampicin; spiropyrazoline benzoates exhibit an average antitubercular activity of 10-100 µg/mL on MTB strains. Molecular docking studies revealed a series of M. tuberculosis receptors with the energies of ligand-receptor complexes (-35.8--42.8 kcal/mol) close to the value of intermolecular pairwise interactions of the same cation in the crystal of spiropyrazolylammonium chloride (-35.3 kcal/mol). However, only in complex with transcriptional repressor EthR2, both stereoisomers of the cation realize similar intermolecular interactions.


Assuntos
Antituberculosos/química , Benzoatos/química , Oxidiazóis/química , Tuberculose/tratamento farmacológico , Antituberculosos/farmacologia , Benzoatos/farmacologia , Cloretos/química , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Oxidiazóis/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo , Relação Estrutura-Atividade , Tuberculose/microbiologia
2.
Carbohydr Polym ; 256: 117510, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33483031

RESUMO

Cellulose nanofibers (CNF) are renewable and biodegradable nanomaterials with attractive barrier, mechanical and surface properties. In this work, three different recombinant enzymes: an endoglucanase, a xylanase and a lytic polysaccharide monooxygenase, were combined to enhance cellulose fibrillation and to produce CNF from sugarcane bagasse (SCB). Prior to the enzymatic catalysis, SCB was chemically pretreated by sodium chlorite and KOH, while defibrillation was accomplished via sonication. We obtained much longer (µm scale length) and more thermostable (resisting up to 260 °C) CNFs as compared to the CNFs prepared by TEMPO-mediated oxidation. Our results showed that a cooperative action of the set of hydrolytic and oxidative enzymes can be used as a "green" treatment prior to the sonication step to produce nanofibrillated cellulose with advanced properties.


Assuntos
Celulase/química , Celulose/química , Endo-1,4-beta-Xilanases/química , Oxigenases de Função Mista/química , Nanofibras/química , Biocatálise , Biodegradação Ambiental , Cloretos/química , Óxidos N-Cíclicos/química , Química Verde , Humanos , Hidrólise , Hidróxidos/química , Nanofibras/ultraestrutura , Oxirredução , Polissacarídeos/química , Compostos de Potássio/química , Saccharum/química , Sonicação
3.
Carbohydr Polym ; 255: 117337, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436180

RESUMO

Pathogens in the food and environment pose a great threat to human health. To solve this problem, we described a novel route to synthesize antibacterial epsilon-poly-L-lysine (EPL) anchored dicarboxyl cellulose beads. Cellulose beads were prepared via a sol-gel transition method and oxidized by sodium periodate and sodium chlorite to form carboxyl groups. EPL was anchored on the beads using carbodiimide mediated amidation. The structure and morphology of beads were characterized by FTIR, XPS, XRD, SEM, and TGA. After dissolution and regeneration, the crystalline form of cellulose is transformed from cellulose I to cellulose II. The thermal degradation temperature of the beads is 200∼300 °C.The samples displayed excellent antimicrobial activity against Staphylococcus aureus, Alicyclobacillus acidoterrestris and Escherichia coli within 12 h. The beads could be biodegraded in soil after 20 days. The biodegradable beads exhibited great potential in food and environmental applications.


Assuntos
Alicyclobacillus/efeitos dos fármacos , Antibacterianos/farmacologia , Celulose/farmacologia , Escherichia coli/efeitos dos fármacos , Polilisina/química , Staphylococcus aureus/efeitos dos fármacos , Alicyclobacillus/crescimento & desenvolvimento , Antibacterianos/síntese química , Biodegradação Ambiental , Carbodi-Imidas/química , Celulose/análogos & derivados , Cloretos/química , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Oxirredução , Ácido Periódico/química , Transição de Fase , Staphylococcus aureus/crescimento & desenvolvimento
4.
Nanotoxicology ; 15(2): 257-275, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33503388

RESUMO

Safety on the use of magnetic nanomaterials (MNMs) has become an active topic of research given all the recent applications of these materials in various fields. It is known that the toxicity of MNMs depends on size, shape, and surface functionalization. In this study, we evaluate the biocompatibility with different aquatic organisms of engineered MNMs-CIT with excellent aqueous dispersion and long-term colloidal stability. Primary producers (the alga Pseudokirchneriella subcapitata), primary consumers (the rotifer Lecane papuana), and predators (the fish, Danio rerio) interacted with these materials in acute and sub-chronic toxicity tests. Our results indicate that P. subcaptita was the most sensitive taxon to MNMs-CIT. Inhibition of their population growth (IC50 = 22.84 mg L-1) elicited cell malformations and increased the content of photosynthetic pigments, likely due to inhibition of cell division (as demonstrated in AFM analysis). For L. papuana, the acute exposure to MNMs shows no significant mortality. However, adverse effects such as decreased rate of population and altered swimming patterns arise after chronic interaction with MNMs. For D. rerio organisms on early life stages, their exposure to MNMs results in delayed hatching of eggs, diminished survival of larvae, altered energy resources allocation (measured as the content of total carbohydrates, lipids, and protein), and increased glucose demand. As to our knowledge, this is the first study that includes three different trophic levels to assess the effect of MNMs in aquatic organisms; furthermore, we demonstrated that these MNMs pose hazards on aquatic food webs at low concentrations (few mgL-1).


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Cloretos/toxicidade , Compostos Férricos/toxicidade , Compostos Ferrosos/toxicidade , Nanoestruturas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/análise , Cloretos/química , Compostos Férricos/química , Compostos Ferrosos/química , Cadeia Alimentar , Larva/efeitos dos fármacos , Fenômenos Magnéticos , Microalgas/efeitos dos fármacos , Nanoestruturas/química , Tamanho da Partícula , Rotíferos/efeitos dos fármacos , Propriedades de Superfície , Poluentes Químicos da Água/química , Peixe-Zebra/crescimento & desenvolvimento
5.
Int J Biol Macromol ; 171: 198-207, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33310102

RESUMO

Chitosan is a linear polysaccharide and non-toxic bioactive polymer with a wide variety of applications due to its functional properties such as ease of modification, and biodegradability. In this investigation, magnetic cores (Fe3O4) were synthesized using a fabrication method involving coprecipitation of Fe2+ and Fe3+. Then the magnetic nanoparticles were encapsulated by chitosan layers. In the next step, magnetite-gold composite nanoparticles were synthesized with spherical shapes and sizes ranging from 20 to 30 nm, using sodium citrate as a natural reducing agent. The morphological and physicochemical features of the material were determined using several advanced techniques like FT-IR, ICP analysis, FESEM, EDS, XRD, TEM, XPS and VSM. In the biological part of the present study, the cell viability of Fe3O4, HAuCl4, and Fe3O4@CS/AuNPs was very low against human colorectal carcinoma cell lines i.e. Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, and HT-29, human gastric cancer cell lines i.e. MKN45, AGS, and KATO III, and human pancreatic cancer cell lines i.e. PANC-1, AsPC-1, and MIA PaCa-2. The IC50 of Fe3O4@CS/AuNPs against Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, HT-29, MKN45, AGS, KATO III, PANC-1, AsPC-1, and MIA PaCa-2 cell lines were 385, 429, 264, 286, 442, 498, 561, 513, 528, and 425 µg/mL, respectively. Thereby, the best cytotoxicity results of our Fe3O4@CS/AuNPs were observed in the case of the HCT 116 cell line. Seemingly, the present nanoparticles may be used for the treatment of several types of gastro-duodenal cancers especially colon, gastric, and pancreatic cancers in near future.


Assuntos
Antineoplásicos/química , Quitosana/química , Cloretos/química , Óxido Ferroso-Férrico/química , Compostos de Ouro/química , Nanopartículas de Magnetita/química , Nanocompostos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Composição de Medicamentos/métodos , Células HCT116 , Células HT29 , Humanos , Nanopartículas de Magnetita/ultraestrutura , Nanocompostos/ultraestrutura , Propilaminas/química , Silanos/química
6.
Carbohydr Polym ; 254: 117303, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357870

RESUMO

Exopolysaccharides (EPS) produced by cyanobacteria are complex biomolecules of anionic nature with potential biomedical applications. In this study, the EPS produced by the Nostoc sp. strains PCC7936 and PCC7413 were characterized and evaluated as a biomaterial for new wound dressings. The addition of acetate ions to the culture medium slightly stimulated EPS production, achieving 1463.1 ± 16.0 mgL-1 (PCC7413) and 1372.1 ± 29.0 mgL-1 (PCC7936). Both EPS presented nine monosaccharide residues and a MW > 1000 kDa. The acetate addition changed the monosaccharide molar percentages. FTIR and DLS results confirmed the anionic nature and the presence of sulfate groups in both EPS, which are determinant features for biomedical applications. Both EPS at 1%(w/v) formed gels in the presence of 0.4%(w/v) FeCl3. Results obtained for MTT assay and wound healing in vitro scratch assay revealed hydrogels biocompatibility and ability to promote fibroblast migration and proliferation that was greater in PCC7936. The Nostoc EPS hydrogels presented promising properties to be applied in the treatment of skin injuries.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Monossacarídeos/química , Nostoc/metabolismo , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/farmacologia , Cicatrização/efeitos dos fármacos , Acetatos/química , Bandagens , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cloretos/química , Sistemas de Liberação de Medicamentos/métodos , Compostos Férricos/química , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Células HeLa , Ácidos Hexurônicos/química , Humanos , Peso Molecular , Polissacarídeos Bacterianos/isolamento & purificação
7.
Methods Mol Biol ; 2217: 183-195, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33215382

RESUMO

Surface nanopatterning allows for the creation of spatially controlled binding sites for extracellular matrix ligands and the modulation of receptor binding sites. Here we describe the preparation of gold nanopatterned substrates using diblock micellar nanolithography to immobilize integrin ligands at defined spacing and combined with molecular tension sensors to measure molecular forces as function of integrin lateral clustering.


Assuntos
Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Adesões Focais/metabolismo , Integrinas/química , Oligodesoxirribonucleotídeos/química , Estereolitografia , Animais , Sítios de Ligação , Adesão Celular , Movimento Celular , Cloretos/química , Matriz Extracelular/ultraestrutura , Fibroblastos/ultraestrutura , Fibronectinas/química , Fibronectinas/metabolismo , Adesões Focais/ultraestrutura , Compostos de Ouro/química , Integrinas/metabolismo , Ligantes , Camundongos , Micelas , Microscopia de Fluorescência/métodos , Nanoestruturas/química , Polietilenoglicóis/química , Polimerização , Ligação Proteica , Piridinas/química , Propriedades de Superfície
8.
Anal Chem ; 93(3): 1529-1536, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33382590

RESUMO

Gold(I) compounds are known to bind sulfur-containing proteins, forming the basis in the design of gold(I)-based drugs. However, the intrinsic molecular mechanism of the chemical reaction is easily hidden when monitored in ensemble. We have previously demonstrated that Mycobacterium smegmatis porin A (MspA) can be engineered (MspA-M) to contain a specialized nanoreactor to probe chemical reactions involving tetrachloroaurate(III). Here, we provide further investigations of coordination interactions between dichloroaurate(I) and MspA-M. Gold compounds of different coordination geometry and valence states are as well probed and evaluated, demonstrating the generality of MspA-M. With single-molecule evidence, MspA-M demonstrates a preference for dichloroaurate(I) than tetrachloroaurate(III), an observation in a single molecule that has never been reported. By counting the maximum number of simultaneous ion bindings, the narrowly confined pore restriction also efficiently distinguishes dichloroaurate(I) and tetrachloroaurate(III) according to their differences in geometry or size. The above demonstration complemented a previous study by demonstrating other possible gold-based single-molecule chemical reactions observable by MspA. These observations bring insights in the understanding of gold-based coordination chemistry in a nanoscale.


Assuntos
Cloretos/química , Compostos de Ouro/química , Mycobacterium smegmatis/química , Nanoporos , Porinas/química , Engenharia de Proteínas , Sítios de Ligação , Ouro/química
9.
J Chem Phys ; 153(22): 224503, 2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33317300

RESUMO

We study, with molecular dynamics simulations, a lysozyme protein immersed in a water-trehalose solution upon cooling. The aim is to understand the cryoprotectant role played by this disaccharide through the modifications that it induces on the slow dynamics of protein hydration water with its presence. The α-relaxation shows a fragile to strong crossover about 20° higher than that in the bulk water phase and 15° higher than that in lysozyme hydration water without trehalose. The protein hydration water without trehalose was found to show a second slower relaxation exhibiting a strong to strong crossover coupled with the protein dynamical transition. This slower relaxation time importantly appears enormously slowed down in our cryoprotectant solution. On the other hand, this long-relaxation in the presence of trehalose is also connected with a stronger damping of the protein structural fluctuations than that found when the protein is in contact with the pure hydration water. Therefore, this appears to be the mechanism through which trehalose manifests its cryoprotecting function.


Assuntos
Muramidase/química , Trealose/química , Água/química , Ânions/química , Cloretos/química , Cinética , Simulação de Dinâmica Molecular , Oxigênio/química
10.
J Vis Exp ; (161)2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32804159

RESUMO

Sulfonamides are prevalent motifs in marketed drugs and natural products. Their synthesis represents a great interest to the pharmaceutical industry, due to their unique biological properties. Recently, several methods for the synthesis of aryl sulfonamides have been developed, but little effort has focused on developing one-step methodologies to access sulfonamides flanked by two alkyl groups. This protocol describes a practical and facile method for the net hydrosulfamoylation of electron-deficient alkenes using sulfamoyl chlorides as radical precursors under blue-light activation. This practical and cost-effective methodology is performed in the presence of the metal-free photocatalyst Eosin Y and uses light as a clean and traceless energy source. The procedure is scalable, displays a broad functional group tolerance, and can be applied for late-stage functionalization. All reagents used in this protocol are commercially available. Simple reaction set-up, the absence of work-up and easy purification, demonstrate the convenience of this protocol. The reaction is best applied to electron-deficient alkenes.


Assuntos
Cloretos/química , Luz , Sulfonamidas/química , Alcenos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Catálise , Elétrons , Espectroscopia de Prótons por Ressonância Magnética
11.
J Chromatogr A ; 1626: 461361, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797840

RESUMO

The alkaloid enantiomers are well-known to have different physiological and pharmacological effects, and to play an important role in enantioselectivity metabolism with enzymes catalysis in tobacco plants. Here, we developed an improved method for simultaneous and high-precision determination of the individual enantiomers of nornicotine, anatabine and anabasine in four tobacco matrices, based on an achiral gas chromatography-nitrogen phosphorus detector (GCNPD) with commonly available Rtx-200 column using (1S)-(-)-camphanic chloride derivatization. The method development consists of the optimization of extraction and derivatization, screening of achiral column, analysis of the fragmentation mechanisms and evaluation of matrix effect (ME). Under the optimized experimental conditions, the current method exhibited excellent detection capability for the alkaloid enantiomers, with coefficients of determination (R2) > 0.9989 and normality test of residuals P > 0.05 in linear regression parameters. The ME can be neglected for the camphanic derivatives. The limit of detection (LOD) and limit of quantitation (LOQ) ranged from 0.087 to 0.24 µg g - 1 and 0.29 to 0.81 µg g - 1, respectively. The recoveries and within-laboratory relative standard deviations (RSDR) were 94.3%~104.2% and 0.51%~3.89%, respectively. The developed method was successfully applied to determine the enantiomeric profiling of cultivars and curing processes. Tobacco cultivars had a significant impact on the nornicotine, anatabine, anabasine concentration and enantiomeric fraction (EF) of (R)-nornicotine, whereas the only significant change induced by the curing processes was an increase in the EF of (R)-anabasine.


Assuntos
Alcaloides/análise , Anabasina/análise , Cromatografia Gasosa/métodos , Nicotina/análogos & derivados , Piridinas/análise , Tabaco/química , Alcaloides/química , Anabasina/química , Hidrocarbonetos Aromáticos com Pontes/química , Cloretos/química , Lactonas/química , Nicotina/análise , Nicotina/química , Piridinas/química , Estereoisomerismo
12.
Am J Physiol Renal Physiol ; 319(3): F534-F540, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32715757

RESUMO

Cl--sensitive with-no-lysine kinase (WNK) plays a key role in regulating the thiazide-sensitive Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT). Cl- enters DCT cells through NCC and leaves the cell across the basolateral membrane via the Cl- channel ClC-K2 or K+-Cl- cotransporter (KCC). While KCC is electroneutral, Cl- exit via ClC-K2 is electrogenic. Therefore, an alteration in DCT basolateral K+ channel activity is expected to influence Cl- movement across the basolateral membrane. Although a role for intracellular Cl- in the regulation of WNK and NCC has been established, intracellular Cl- concentrations ([Cl-]i) have not been directly measured in the mammalian DCT. Therefore, to measure [Cl-]i in DCT cells, we generated a transgenic mouse model expressing an optogenetic kidney-specific Cl-Sensor and measured Cl- fluorescent imaging in the isolated DCT. Basal measurements indicated that the mean [Cl-]i was ~7 mM. Stimulation of Cl- exit with low-Cl- hypotonic solutions decreased [Cl-]i, whereas inhibition of KCC by DIOA or inhibition of ClC-K2 by NPPB increased [Cl-]i, suggesting roles for both KCC and ClC-K2 in the modulation of [Cl-]i . Blockade of basolateral K+ channels (Kir4.1/5.1) with barium significantly increased [Cl-]i. Finally, a decrease in extracellular K+ concentration transiently decreased [Cl-]i, whereas raising extracellular K+ transiently increased [Cl-]i, further suggesting a role for Kir4.1/5.1 in the regulation of [Cl-]i. We conclude that the alteration in ClC-K2, KCC, and Kir4.1/5.1 activity influences [Cl-]i in the DCT.


Assuntos
Cloretos/metabolismo , Túbulos Renais Distais/fisiologia , Canais de Potássio/metabolismo , Simportadores de Cloreto de Sódio/metabolismo , Animais , Cloretos/química , Fenômenos Eletrofisiológicos , Camundongos , Imagem Molecular , Simportadores de Cloreto de Sódio/genética
13.
Acta Cir Bras ; 35(5): e202000507, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32638846

RESUMO

PURPOSE: To develop a new wound dressing composed of alginate and Aloe vera gel and cross-linked with zinc ions. METHODS: The aloe-alginate film was characterized using scanning electron microscopy (SEM), swelling profile, mechanical properties, polysaccharide content and X-ray diffraction (XRD). Thirty Wistar rats were divided in two groups a) treated with aloe-alginate film and b) control (treated with sterile gauze). Wound contraction measurements and hystological analysis were performed on 7th, 14th and 21st days after wound surgery. RESULTS: The aloe-alginate film presented adequated mechanical resistance and malleability for application as wound dressing. There was no statistical difference in wound contraction between two groups. Histological assay demonstrated that aloe-alginate film presented anti-inflammatory activity, stimulated angiogenesis on proliferative phase and a more significant increased in collagen type I fibers and decreased type III fibers which promoted a mature scar formation when compared to control. CONCLUSIONS: The aloe-alginate film showed adequate physicochemical characteristics for wound dressing applications. The in vivo assay demonstrated that aloe-alginate film enhanced the healing process of incisional skin wounds.


Assuntos
Alginatos , Aloe , Cloretos , Preparações de Plantas , Cicatrização , Compostos de Zinco , Alginatos/farmacologia , Animais , Cloretos/química , Cloretos/farmacologia , Preparações de Plantas/farmacologia , Ratos , Ratos Wistar , Cicatrização/efeitos dos fármacos , Compostos de Zinco/química , Compostos de Zinco/farmacologia
14.
Am J Physiol Cell Physiol ; 319(2): C371-C380, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32579473

RESUMO

Cation-coupled chloride cotransporters (CCC) play a role in modulating intracellular chloride concentration ([Cl-]i) and cell volume. Cell shrinkage and cell swelling are accompanied by an increase or decrease in [Cl-]i, respectively. Cell shrinkage and a decrease in [Cl-]i increase the activity of NKCCs (Na-K-Cl cotransporters: NKCC1, NKCC2, and Na-Cl) and inhibit the activity of KCCs (K-Cl cotransporters: KCC1 to KCC4), wheras cell swelling and an increase in [Cl-]i activate KCCs and inhibit NKCCs; thus, it is unlikely that the same kinase is responsible for both effects. WNK1 and WNK4 are chloride-sensitive kinases that modulate the activity of CCC in response to changes in [Cl-]i. Here, we showed that WNK3, another member of the serine-threonine kinase WNK family with known effects on CCC, is not sensitive to [Cl-]i but can be regulated by changes in extracellular tonicity. In contrast, WNK4 is highly sensitive to [Cl-]i but is not regulated by changes in cell volume. The activity of WNK3 toward NaCl cotransporter is not affected by eliminating the chloride-binding site of WNK3, further confirming that the kinase is not sensitive to chloride. Chimeric WNK3/WNK4 proteins were produced, and analysis of the chimeras suggests that sequences within the WNK's carboxy-terminal end may modulate the chloride affinity. We propose that WNK3 is a cell volume-sensitive kinase that translates changes in cell volume into phosphorylation of CCC.


Assuntos
Tamanho Celular , Proteínas Serina-Treonina Quinases/genética , Simportadores de Cloreto de Sódio/metabolismo , Proteínas de Xenopus/genética , Animais , Cloretos/química , Cloretos/metabolismo , Citoplasma/química , Citoplasma/metabolismo , Humanos , Oócitos/química , Oócitos/metabolismo , Fosforilação/genética , Proteínas Serina-Treonina Quinases/metabolismo , Simportadores de Cloreto de Sódio/química , Xenopus/genética , Xenopus/metabolismo , Proteínas de Xenopus/metabolismo , Xenopus laevis/genética , Xenopus laevis/metabolismo
15.
Hosp Pract (1995) ; 48(4): 165-168, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32497459

RESUMO

Limited availability of personal protective equipment is endangering first-line health-care providers treating patients with presumed or confirmed COVID-19 infections. This editorial has multiple objectives in regard to this reality: First, to raise awareness of the need for safe and effective prophylaxis to protect health-care providers with insufficient personal protective equipment from repeated exposures to COVID-19. Second, to summarize the scientific evidence in support of solutions of acidified sodium chlorite (ASC) and its daughter compounds, chlorous acid and chlorine dioxide, as potential targets for said prophylactic use. Third, to propose a regimented protocol using commercially available solutions of ASC having sufficient concentrations of chlorine dioxide for virucidal activity to support safe and effective prophylactic use. And fourth, to raise awareness of and compare other potential prophylactic options currently under investigation.


Assuntos
Betacoronavirus/efeitos dos fármacos , Cloretos/administração & dosagem , Cloretos/farmacologia , Infecções por Coronavirus/transmissão , Transmissão de Doença Infecciosa/prevenção & controle , Corpo Clínico Hospitalar , Pneumonia Viral/transmissão , Profilaxia Pré-Exposição/normas , Cloretos/química , Tolerância a Medicamentos , Humanos , Pandemias
16.
Sci Rep ; 10(1): 7699, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32382047

RESUMO

Wearable sensors enable the monitoring of an individual's sweat composition in real time. In this work, we recorded real-time sweat chloride concentration for 12 healthy subjects in three different protocols involving step changes in exercise load and compared the results to laboratory-based analysis. The sensor results reflected the changes in exercise load in real time. On increasing the exercise load from 100 W to 200 W the sweat chloride concentration increased from 12.0 ± 5.9 to 31.4 ± 16 mM (mean ± SD). On decreasing the load from 200 W to 100 W, the sweat chloride concentration decreased from 27.7 ± 10.5 to 14.8 ± 8.1 mM. The half-time associated with the change in sweat chloride, defined as the time at which the concentration reached half of the overall change, was about 6 minutes. While the changes in sweat chloride were statistically significant, there was no correlation with changes in sweat rate or other physiological parameters, which we attribute to intra-individual variation (SD = 1.6-8.1 mM). The response to exercise-induced sweating was significantly different to chemically-induced sweating where the sweat chloride concentration was almost independent of sweat rate. We speculate that this difference is related to changes in the open probability of the CFTR channel during exercise, resulting in a decrease in reabsorption efficiency at higher sweat rates.


Assuntos
Técnicas Biossensoriais , Cloretos/isolamento & purificação , Exercício Físico , Suor/química , Adolescente , Adulto , Cloretos/química , Feminino , Humanos , Masculino , Dispositivos Eletrônicos Vestíveis , Adulto Jovem
17.
Chemosphere ; 252: 126528, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32443263

RESUMO

The landfill sludge in storage reservoirs needs to be dewatered and disposed of for environmental and engineering purposes. The key factors are the high organic matter content and low permeability. Chemical conditioning is considered an efficient method for adjusting the properties of sludge. In this paper, two typical chemical agents, FeCl3 and a Fenton reagent with different additive amounts, are studied and compared for dewatering and consolidation purposes. Compression experiments and consolidation experiments are compared, and the coefficient of compressibility and compression index are obtained and compared. Then, the sludge permeability, grain size distribution variations, specific resistance to filtration (SRF) and morphology observations are considered to analyse the treatment mechanism. The results indicate that the properties of landfill sludge will change as the curing time increases. FeCl3 and Fenton are both effective in improving the consolidation and permeability properties of sludge. For the conditioning process, the optimum FeCl3 content is 20%, and the process is dominated by coagulation if FeCl3 is less than 20%; otherwise, it is dominated by hydrolysis. For the Fenton reagent, the optimum Fe2+ content and H2O2 content are 4% and 12%, respectively. The depolymerization effect of the Fenton reagent leads to the oxidation and recombination of the polar group on extracellular polymeric substances (EPSs). The results can be used to explain the conditioning mechanism of the effective agents of FeCl3 and Fenton and compare the corresponding consolidation properties. The consolidation characteristics provide a reference for further application of vacuum preloading in the sludge disposal process.


Assuntos
Cloretos/química , Compostos Férricos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Filtração , Peróxido de Hidrogênio/química , Ferro/química , Oxirredução , Esgotos/química , Instalações de Eliminação de Resíduos , Água/química
18.
PLoS Comput Biol ; 16(5): e1007932, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32453795

RESUMO

Fast synaptic inhibition is a critical determinant of neuronal output, with subcellular targeting of synaptic inhibition able to exert different transformations of the neuronal input-output function. At the receptor level, synaptic inhibition is primarily mediated by chloride-permeable Type A GABA receptors. Consequently, dynamics in the neuronal chloride concentration can alter the functional properties of inhibitory synapses. How differences in the spatial targeting of inhibitory synapses interact with intracellular chloride dynamics to modulate the input-output function of neurons is not well understood. To address this, we developed computational models of multi-compartment neurons that incorporate experimentally parametrised mechanisms to account for neuronal chloride influx, diffusion, and extrusion. We found that synaptic input (either excitatory, inhibitory, or both) can lead to subcellular variations in chloride concentration, despite a uniform distribution of chloride extrusion mechanisms. Accounting for chloride changes resulted in substantial alterations in the neuronal input-output function. This was particularly the case for peripherally targeted dendritic inhibition where dynamic chloride compromised the ability of inhibition to offset neuronal input-output curves. Our simulations revealed that progressive changes in chloride concentration mean that the neuronal input-output function is not static but varies significantly as a function of the duration of synaptic drive. Finally, we found that the observed effects of dynamic chloride on neuronal output were mediated by changes in the dendritic reversal potential for GABA. Our findings provide a framework for understanding the computational effects of chloride dynamics on dendritically targeted synaptic inhibition.


Assuntos
Cloretos/química , Dendritos/fisiologia , Neurônios/fisiologia , Receptores de GABA/fisiologia , Sinapses/fisiologia , Potenciais de Ação , Animais , Encéfalo/fisiologia , Simulação por Computador , Hipocampo/fisiologia , Humanos , Cinética , Masculino , Modelos Neurológicos , Técnicas de Cultura de Órgãos , Ligação Proteica , Células Piramidais/fisiologia , Ratos , Ratos Wistar , Receptores de GABA-A/fisiologia
19.
Acta Crystallogr C Struct Chem ; 76(Pt 5): 476-482, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32367829

RESUMO

Reaction of N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide), C20H18F2N4O2, (LF), with zinc chloride and mercury(II) chloride produced different types and shapes of neutral coordination complexes, namely, dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ2N,O]zinc(II), [ZnCl2(C20H18F2N4O2)], (1), and dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ4O,N,N',O']mercury(II), [HgCl2(C20H18F2N4O2)], (2). The organic ligand and its metal complexes are characterized using various techniques: IR, UV-Vis and nuclear magnetic resonance (NMR) spectroscopies, in addition to powder X-ray diffraction (PXRD), single-crystal X-ray crystallography and microelemental analysis. Depending upon the data from these analyses and measurements, a typical tetrahedral geometry was confirmed for zinc complex (1), in which the ZnII atom is located outside the bis(benzhydrazone) core. The HgII atom in (2) is found within the core and has a common octahedral structure. The in vitro antibacterial activities of the prepared compounds were evaluated against two different bacterial strains, i.e. gram positive Bacillus subtilis and gram negative Pseudomonas aeruginosa bacteria. The prepared compounds exhibited differentiated growth-inhibitory activities against these two bacterial strains based on the difference in their lipophilic nature and structural features.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Cloretos/farmacologia , Mercúrio/química , Compostos de Zinco/farmacologia , Zinco/química , Antibacterianos/química , Cloretos/química , Complexos de Coordenação/química , Cristalografia por Raios X , Difração de Raios X , Compostos de Zinco/química
20.
Int J Nanomedicine ; 15: 2605-2615, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368043

RESUMO

Objective: This paper introduces a simple one-step and ultra-fast method for synthesis of highly photothermally active polypyrrole-coated gold nanoparticles. The synthesis process is so simple that the reaction is very fast without the need for any additives or complicated steps. Methodology: Polypyrrole-coated gold nanoparticles (AuPpy NPs) were synthesized by reacting chloroauric acid (HAuCl4) with pyrrole (monomer) in aqueous medium at room temperature. These nanoparticles were characterized by UV-visible-NIR spectrometry, transmission electron microscopy (TEM), AC conductivity, zeta sizer and were evaluated for dark cytotoxicity and photocytotoxicity using human hepatocellular carcinoma (HepG2) cell line as a model for cancer cells. Results: The synthesized AuPpy NPs showed a peak characteristic for gold nanoparticles (530-600 nm, molar ratio dependent) and a wide absorption band along the visible-NIR region with intensity about triple or even quadruple that of polypyrrole synthesized by the conventional FeCl3 method at the same concentration and under the same conditions. TEM imaging showed that the synthesized AuPpy NPs were composed of spherical or semi-spherical gold core(s) of about 4-10 nm coated with distinct layer(s) of polypyrrole seen either loosely or in clusters. Mean sizes of the synthesized nanoparticles range between ~25 and 220 nm (molar ratio dependent). Zeta potentials of the AuPpy NPs preparations indicate their good colloidal stability. AC conductivity values of AuPpy NPs highly surpass that of Ppy prepared by the conventional FeCl3 method. AuPpy NPs were non-toxic even at high concentrations (up to 1000 µM pyrrole monomer equivalent) under dark conditions. Unlikely, light activated the photothermal activity of AuPpy NPs in a dose-dependent manner. Conclusion: This method simply and successfully synthesized AuPpy NPs nanoparticles that represent a safe alternative photothermally active multifunctional tool instead of highly toxic and non-biodegradable gold nanorods.


Assuntos
Materiais Revestidos Biocompatíveis/química , Ouro/química , Luz , Nanopartículas Metálicas/química , Polímeros/química , Pirróis/química , Temperatura , Morte Celular , Cloretos/química , Condutividade Elétrica , Compostos de Ouro/química , Células Hep G2 , Humanos , Nanopartículas Metálicas/ultraestrutura , Tamanho da Partícula , Polímeros/síntese química , Pirróis/síntese química , Espectrofotometria Ultravioleta , Eletricidade Estática
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