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1.
Life Sci ; 244: 117333, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-31962132

RESUMEN

AIMS: Detect the antiarrhythmic effect of crotonoside (Cro). MAIN METHODS: We used whole-cell patch-clamp techniques to detect the effects of Cro on action potentials (APs) and transmembrane ion currents in isolated rabbit left ventricular myocytes. We also verified the effect of Cro on ventricular arrhythmias caused by aconitine in vivo. KEY FINDINGS: Cro reduced the maximum depolarization velocity (Vmax) of APs and shortened the action potential duration (APD) in a concentration-dependent manner, but it had no significant effect on the resting membrane potential (RMP) or action potential amplitude (APA). It also inhibited the peak sodium current (INa) and L-type calcium current (ICaL) in a concentration-dependent manner with half-maximal inhibitory concentrations (IC50) of 192 µmol/L and 159 µmol/L, respectively. However, Cro had no significant effects on the inward rectifier potassium current (IK1) or rapidly activating delayed rectifier potassium current (IKr). Sea anemone toxin II (ATX II) increased the late sodium current (INaL), but Cro abolished this effect. Moreover, Cro significantly abolished ATX II-induced early afterdepolarizations (EADs) and high extracellular Ca2+ concentration (3.6 mmol/L)-induced delayed afterdepolarizations (DADs). We also verified that Cro effectively delayed the onset time and reduced the incidence of ventricular arrhythmias caused by aconitine in vivo. SIGNIFICANCE: These results revealed that Cro effectively inhibits INa, INaL, and ICaL in ventricular myocytes. Cro has antiarrhythmic potential and thus deserves further study.


Asunto(s)
Guanina/farmacología , Miocitos Cardíacos/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Animales , Antiarrítmicos/metabolismo , Antiarrítmicos/farmacología , Arritmias Cardíacas/fisiopatología , Calcio/metabolismo , Canales de Calcio/efectos de los fármacos , China , Femenino , Guanina/metabolismo , Ventrículos Cardíacos/metabolismo , Técnicas de Placa-Clamp/métodos , Conejos , Sodio/metabolismo , Canales de Sodio/efectos de los fármacos
2.
J Chem Theory Comput ; 16(1): 738-748, 2020 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-31762275

RESUMEN

Phosphatidylserine (PS) lipids are important signaling molecules and the most common negatively charged lipids in eukaryotic membranes. The signaling can be often regulated by calcium, but its interactions with PS headgroups are not fully understood. Classical molecular dynamics (MD) simulations can potentially give detailed description of lipid-ion interactions, but the results strongly depend on the used force field. Here, we apply the electronic continuum correction (ECC) to the Amber Lipid17 parameters of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS) lipid to improve its interactions with K+, Na+, and Ca2+ ions. The partial charges of the headgroup, glycerol backbone, and carbonyls of POPS, bearing a unit negative charge, were scaled with a factor of 0.75, derived for monovalent ions, and the Lennard-Jones σ parameters of the same segments were scaled with a factor of 0.89. The resulting ECC-POPS model gives more realistic interactions with Na+ and Ca2+ cations than the original Amber Lipid17 parameters when validated using headgroup order parameters and the "electrometer concept". In ECC-lipids simulations, populations of complexes of Ca2+ cations with more than two PS lipids are negligible, and interactions of Ca2+ cations with only carboxylate groups are twice more likely than with only phosphate groups, while interactions with carbonyls almost entirely involve other groups as well. Our results pave the way for more realistic MD simulations of biomolecular systems with anionic membranes, allowing signaling processes involving PS and Ca2+ to be elucidated.


Asunto(s)
Calcio/metabolismo , Membrana Dobles de Lípidos/metabolismo , Fosfatidilserinas/metabolismo , Potasio/metabolismo , Sodio/metabolismo , Cationes/metabolismo , Electrones , Simulación de Dinámica Molecular
3.
Ecotoxicol Environ Saf ; 187: 109814, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31648076

RESUMEN

Soil salinity and arsenic (As) contamination are serious environmental problems. To investigate the effects of salinity on As uptake and physiological and biochemical attributes of quinoa (Chenopodiumquinoa Willd.), a hydroponic experiment was performed. One-month old healthy plants of two quinoa genotypes; Vikinga and A7 were transplanted in plastic tubs containing half strength Hoagland's nutrient solution. Plants were exposed to different levels of As (0, 150 and 300 µM), salinity (0, 150 and 300 mM) and their combinations (150 µM As + 300 mM NaCl; 300 µM As + 300 mM NaCl) for five weeks. Results revealed that combined application of salinity and As caused more pronounced reduction in growth, chlorophyll contents and caused more oxidative damage in both quinoa genotypes. Under combined application of salinity and As, Na+ concentration was increased whereas As content was decreased in plant tissues. Quinoa genotype A7 was more tolerant than Vikinga against salinity, As and their combination perhaps because of less uptake of toxic ions and higher activities of antioxidant enzymes (SOD, CAT, POD). Bioconcentration factor (BCF), translocation factor (TF) and tolerance index (TI) indicated that genotype A7 can be successfully employed for phytostabilization of As contaminated saline soils.


Asunto(s)
Adaptación Fisiológica/efectos de los fármacos , Arsénico/toxicidad , Chenopodium quinoa/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Contaminantes del Suelo/toxicidad , Suelo/química , Adaptación Fisiológica/genética , Antioxidantes/metabolismo , Chenopodium quinoa/genética , Chenopodium quinoa/metabolismo , Clorofila/metabolismo , Genotipo , Iones , Estrés Oxidativo/genética , Salinidad , Sodio/metabolismo , Cloruro de Sodio/farmacología
4.
J Sci Food Agric ; 100(2): 794-802, 2020 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-31612484

RESUMEN

BACKGROUND: Low-sodium sausages were manufactured using sodium substitution and biopolymer encapsulation. A diet comprising 10% treatment sausages (six treatment groups: C (100% NaCl), T1 (55% sodium substitute + 45% saltwort salt), T2 (55% sodium substitute + 45% saltwort salt with chitosan), T3 (55% sodium substitute + 45% saltwort salt with cellulose), T4 (55% sodium substitute + 45% saltwort salt with dextrin), and T5 (55% sodium substitute + 45% saltwort salt with pectin)) was added to a 90% commercial mouse diet for 4 weeks. RESULTS: Subacute toxicity, hematology, liver function, and organ weight tests in low-sodium sausage groups showed results similar to those of the control group, and all toxicity test levels were within normal ranges. CONCLUSIONS: All low-sodium sausage types tested are suggested to be safe in terms of subacute toxicity. Moreover, low-sodium sausages can be manufactured by biopolymer encapsulation of saltwort using pectin, chitosan, cellulose, and dextrin without toxicity. © 2019 Society of Chemical Industry.


Asunto(s)
Biopolímeros/análisis , Aditivos Alimentarios/análisis , Manipulación de Alimentos/métodos , Productos de la Carne/análisis , Salsola/química , Sodio/análisis , Animales , Biopolímeros/metabolismo , Biopolímeros/toxicidad , Celulosa/análisis , Celulosa/metabolismo , Celulosa/toxicidad , Quitosano/análisis , Quitosano/metabolismo , Quitosano/toxicidad , Femenino , Aditivos Alimentarios/metabolismo , Aditivos Alimentarios/toxicidad , Manipulación de Alimentos/instrumentación , Masculino , Productos de la Carne/toxicidad , Ratones , Ratones Endogámicos ICR , Salsola/metabolismo , Salsola/toxicidad , Sodio/metabolismo , Sodio/toxicidad , Porcinos
5.
Ecotoxicol Environ Saf ; 188: 109894, 2020 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-31706239

RESUMEN

Modulation of plant salt tolerance has been drawing great attention. Thymol is a kind of natural chemical that has been developed as anti-microbial reagent and medicine. To date, we still have limited knowledge about thymol-modulated plant physiology. In this work, physiological, histochemical, and biochemical methods were adopted to study thymol-conferred salt resistance in the root of rice (Oryza sativa). Thymol significantly rescued root growth under salt stress. Thymol ameliorated cell membrane damage, oxidative stress, ROS accumulation, and cell death in roots under salt stress. Thymol-attenuated oxidative stress may be resulted from the activation of anti-oxidative capacity, including both enzymatic and non-enzymatic system. Thymol treatment significantly decreased Na+ content in root cells upon salt stress, which might be ascribed to the upregulation of OsSOS1 (salt overly sensitive 1) facilitating Na+ exclusion. In addition, thymol stimulated the expression of genes encoding tonoplast OsNHX (Na+/H+antiporter), which may help root cells to compartmentalize Na+ in vacuole. The results of these works evidenced that thymol was capable of inducing salt tolerance by reestablishing ROS homeostasis and modulating cellular Na+ flux in rice roots. These findings may be applicable to improve crop growth in salinity area.


Asunto(s)
Antioxidantes/metabolismo , Homeostasis/efectos de los fármacos , Oryza/efectos de los fármacos , Tolerancia a la Sal/efectos de los fármacos , Sodio/metabolismo , Timol/farmacología , Iones/metabolismo , Oryza/metabolismo , Estrés Oxidativo/efectos de los fármacos , Proteínas de Plantas/metabolismo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Plantas Tolerantes a la Sal , Intercambiadores de Sodio-Hidrógeno/metabolismo
6.
Phys Rev Lett ; 123(21): 218101, 2019 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-31809131

RESUMEN

We develop an iterated map model to describe the bifurcations and complex dynamics caused by the feedback between voltage and intracellular Ca^{2+} and Na^{+} concentrations in paced ventricular myocytes. Voltage and Ca^{2+} can form either a positive or a negative feedback loop, while voltage and Na^{+} form a negative feedback loop. Under certain diseased conditions, when the feedback between voltage and Ca^{2+} is positive, Hopf bifurcations occur, leading to periodic oscillatory behaviors. When this feedback is negative, period-doubling bifurcation routes to alternans and chaos occur.


Asunto(s)
Calcio/metabolismo , Modelos Cardiovasculares , Miocitos Cardíacos/metabolismo , Sodio/metabolismo , Relojes Biológicos , Cationes Bivalentes/metabolismo , Cationes Monovalentes/metabolismo , Membrana Celular/metabolismo , Polaridad Celular , Retroalimentación Fisiológica , Ventrículos Cardíacos/citología , Ventrículos Cardíacos/metabolismo , Potenciales de la Membrana , Miocitos Cardíacos/citología , Intercambiador de Sodio-Calcio/metabolismo
7.
Biochemistry (Mosc) ; 84(11): 1280-1295, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31760918

RESUMEN

Maintenance of non-equilibrium Na+ and K+ distribution between cytoplasm and extracellular medium suggests existence of sensors responding with conformational transitions to the changes of these monovalent cations' intracellular concentration. Molecular nature of monovalent cation sensors has been established in Na,K-ATPase, G-protein-coupled receptors, and heat shock proteins structural studies. Recently, it was found that changes in Na+ and K+ intracellular concentration are the key factors in the transcription and translation control, respectively. In this review, we summarize results of these studies and discuss physiological and pathophysiological significance of Na+i,K+i-dependent gene expression regulation mechanism.


Asunto(s)
Potasio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Sodio/metabolismo , Animales , Cationes Monovalentes/química , Citoplasma/metabolismo , Proteínas de Choque Térmico/metabolismo , Potasio/química , Biosíntesis de Proteínas , Sodio/química , Transcripción Genética
8.
World J Microbiol Biotechnol ; 35(11): 170, 2019 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-31673816

RESUMEN

Debaryomyces hansenii is a halotolerant yeast of importance in basic and applied research. Previous reports hinted about possible links between saline and oxidative stress responses in this yeast. The aim of this work was to study that hypothesis at different molecular levels, investigating after oxidative and saline stress: (i) transcription of seven genes related to oxidative and/or saline responses, (ii) activity of two main anti-oxidative enzymes, (iii) existence of common metabolic intermediates, and (iv) generation of damages to biomolecules as lipids and proteins. Our results showed how expression of genes related to oxidative stress was induced by exposure to NaCl and KCl, and, vice versa, transcription of some genes related to osmotic/salt stress responses was regulated by H2O2. Moreover, and contrary to S. cerevisiae, in D. hansenii HOG1 and MSN2 genes were modulated by stress at their transcriptional level. At the enzymatic level, saline stress also induced antioxidative enzymatic defenses as catalase and glutathione reductase. Furthermore, we demonstrated that both stresses are connected by the generation of intracellular ROS, and that hydrogen peroxide can affect the accumulation of in-cell sodium. On the other hand, no significant alterations in lipid oxidation or total glutathione content were observed upon exposure to both stresses tested. The results described in this work could help to understand the responses to both stressors, and to improve the biotechnological potential of D. hansenni.


Asunto(s)
Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Estrés Oxidativo/fisiología , Saccharomycetales/fisiología , Estrés Salino/fisiología , Antioxidantes , Catalasa/metabolismo , Proteínas de Unión al ADN/genética , Regulación Fúngica de la Expresión Génica , Genes Fúngicos/genética , Glutatión/metabolismo , Glutatión Reductasa/metabolismo , Peróxido de Hidrógeno , Metabolismo de los Lípidos , Osmorregulación/genética , Osmorregulación/fisiología , Estrés Oxidativo/genética , Cloruro de Potasio/metabolismo , Proteómica , Saccharomycetales/genética , Estrés Salino/genética , Sodio/metabolismo , Cloruro de Sodio/metabolismo , Factores de Transcripción/genética
9.
Bioelectromagnetics ; 40(8): 578-587, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31642089

RESUMEN

A sub-acute electromagnetic field (EMF) biological effect study was carried out on rats exposed in the Transverse ElectroMagnetic exposure chamber at 171 MHz Continuous Wave (CW). The experiments involved three exposure levels (15, 25, and 35 V/m) for 15 days with triplicate parallel sham-exposed controls in each series. All exposure conditions were simulated for the evaluation of the electromagnetic energy distribution and specific absorption rate (SAR) in the rat phantoms. Studies have shown a biphasic biological response depending on time and absorbed electromagnetic energy. Under low SAR, approximately 0.006 W/kg, EMF exposure leads to the stimulation of adrenal gland activity. This process is accompanied by an initial increase of daily excretion of corticosterone and Na+ , which is seen as a higher Na+ /K+ ratio, followed by a decrease of these parameters over time. It is possible that EMF exposure causes a stress response in animals, which is seen as an increased adrenal activity. Bioelectromagnetics. 2019;40:578-587. © 2019 Bioelectromagnetics Society.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Campos Electromagnéticos/efectos adversos , Glucocorticoides/metabolismo , Mineralocorticoides/metabolismo , Animales , Corticosterona/metabolismo , Masculino , Potasio/metabolismo , Ratas , Ratas Wistar , Sodio/metabolismo
10.
Plant Sci ; 289: 110260, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31623790

RESUMEN

The potential of Arundo donax to grow in degraded soils, characterized by excess of salinity (Na+), and phosphorus deficiency (-P) or excess (+P) also coupled with salinity (+NaP), was investigated by combining in vivo plant phenotyping, quantification of metabolites and ultrastructural imaging of leaves with a transcriptome-wide screening. Photosynthesis and growth were impaired by + Na, -P and + NaP. While + Na caused stomatal closure, enhanced biosynthesis of carotenoids, sucrose and isoprene and impaired anatomy of cell walls, +P negatively affected starch production and isoprene emission, and damaged chloroplasts. Finally, +NaP largely inhibited photosynthesis due to stomatal limitations, increased sugar content, induced/repressed a number of genes 10 time higher with respect to + P and + Na, and caused appearance of numerous and large plastoglobules and starch granules in chloroplasts. Our results show that A. donax is sensitive to unbalances of soil ion content, despite activation of defensive mechanisms that enhance plant resilience, growth and biomass production of A. donax under these conditions.


Asunto(s)
Fósforo/metabolismo , Poaceae/fisiología , Estrés Salino , Sodio/metabolismo , Fósforo/deficiencia , Poaceae/genética , Sodio/efectos adversos , Suelo/química
11.
J Agric Food Chem ; 67(43): 12026-12036, 2019 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-31589432

RESUMEN

Peanut is an important legume providing products with nutrient dense including mineral nutrition. However, the genetic basis underlying the variations in the mineral composition in peanut is still unknown. Genome-wide association studies (GWAS) of the concentrations of 13 mineral elements combined with coexpression network were performed using a diverse panel of 120 genotypes mainly selected from the U.S. peanut mini core collection. A total of 36 significant quantitative trait loci (QTLs) associated with five elemental concentrations were identified with phenotypic variation explained (PVE) from 18.35% to 27.56%, in which 24 QTLs were for boron (B), 2 QTLs for copper (Cu), 6 QTLs for sodium (Na), 3 QTLs for sulfur (S), and 1 QTL for zinc (Zn). A total of 110 nonredundant candidate causal genes identified were significantly associated with elemental accumulation, which included one high-priority overlap (HPO) candidate gene arahy.KQD4NT, an important elemental/metal transporter gene located on LGB04 with position 5,413,913-5,417,353.


Asunto(s)
Arachis/genética , Boro/metabolismo , Cobre/metabolismo , Proteínas de Plantas/genética , Sodio/metabolismo , Azufre/metabolismo , Zinc/metabolismo , Arachis/crecimiento & desarrollo , Arachis/metabolismo , Estudio de Asociación del Genoma Completo , Genotipo , Proteínas de Plantas/metabolismo , Sitios de Carácter Cuantitativo
12.
Cell Physiol Biochem ; 53(4): 638-647, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31556253

RESUMEN

BACKGROUND/AIMS: Prolonged hyperosmotic shrinkage evokes expression of osmoprotective genes via nuclear factor NFAT5-mediated pathway and activates Na+ influx via hypertonicity-induced cation channels (HICC). In human umbilical vein endothelial cells (HUVEC) elevation of intracellular sodium concentration ([Na+]i) triggers transcription of dozens of early response genes (ERG). This study examined the role of monovalent cations in the expression of Na+i-sensitive ERGs in iso- and hyperosmotically shrunken HUVEC. METHODS: Cell volume was measured by 3D reconstruction of cell shape and as 14C-urea available space. Intracellular Na+ and K+ content was measured by flame atomic absorption spectrometry. ERG transcription was estimated by RT-PCR. RESULTS: Elevation of medium osmolality by 150 mM mannitol or cell transfer from hypo- to isosmotic medium decreased cell volume by 40-50%. Hyperosmotic medium increased [Na+]i by 2-fold whereas isosmotic shrinkage had no impact on this parameter. Hyperosmotic but not isosmotic shrinkage increased up-to 5-fold the content of EGR1, FOS, ATF3, ZFP36 and JUN mRNAs. Expression of these ERGs triggered by hyperosmotic shrinkage and Na+,K+-ATPase inhibition by 0.1 µM ouabain exhibited positive correlation (R2=0.9383, p=0.0005). Isosmotic substitution of NaCl by N-methyl-D-glucamine abolished an increment of [Na+]i and ERG expression triggered by mannitol addition. CONCLUSION: Augmented expression of ERGs in hyperosmotically shrunken HUVEC is mediated by elevation of [Na+]i.


Asunto(s)
Tamaño de la Célula , Sodio/metabolismo , Tamaño de la Célula/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Proteína 1 de la Respuesta de Crecimiento Precoz/genética , Proteína 1 de la Respuesta de Crecimiento Precoz/metabolismo , Células Endoteliales de la Vena Umbilical Humana , Humanos , Meglumina/farmacología , Ouabaína/farmacología , Potasio/metabolismo , Cloruro de Sodio/farmacología , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidores , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Tristetraprolina/genética , Tristetraprolina/metabolismo
13.
Elife ; 82019 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-31532390

RESUMEN

Cystic Fibrosis (CF) is a monogenic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, resulting in defective CFTR-mediated chloride and bicarbonate transport, with dysregulation of epithelial sodium channels (ENaC). These changes alter fluid and electrolyte homeostasis and result in an exaggerated proinflammatory response driven, in part, by infection. We tested the hypothesis that NLRP3 inflammasome activation and ENaC upregulation drives exaggerated innate-immune responses in this multisystem disease. We identify an enhanced proinflammatory signature, as evidenced by increased levels of IL-18, IL-1ß, caspase-1 activity and ASC-speck release in monocytes, epithelia and serum with CF-associated mutations; these differences were reversed by pretreatment with NLRP3 inflammasome inhibitors and notably, inhibition of amiloride-sensitive sodium (Na+) channels. Overexpression of ß-ENaC, in the absence of CFTR dysfunction, increased NLRP3-mediated inflammation, indicating that dysregulated, ENaC-dependent signalling may drive exaggerated inflammatory responses in CF. These data support a role for sodium in modulating NLRP3 inflammasome activation.


Asunto(s)
Fibrosis Quística/patología , Canales Epiteliales de Sodio/metabolismo , Inflamación/patología , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Sodio/metabolismo , Línea Celular , Humanos , Inmunidad Innata
14.
Pharmacol Rev ; 71(4): 571-595, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31551350

RESUMEN

Endogenous ions play important roles in the function and pharmacology of G-protein coupled receptors (GPCRs). Historically the evidence for ionic modulation of GPCR function dates to 1973 with studies of opioid receptors, where it was demonstrated that physiologic concentrations of sodium allosterically attenuated agonist binding. This Na+-selective effect was distinct from effects of other monovalent and divalent cations, with the latter usually counteracting sodium's negative allosteric modulation of binding. Since then, numerous studies documenting the effects of mono- and divalent ions on GPCR function have been published. While ions can act selectively and nonselectively at many sites in different receptors, the discovery of the conserved sodium ion site in class A GPCR structures in 2012 revealed the unique nature of Na+ site, which has emerged as a near-universal site for allosteric modulation of class A GPCR structure and function. In this review, we synthesize and highlight recent advances in the functional, biophysical, and structural characterization of ions bound to GPCRs. Taken together, these findings provide a molecular understanding of the unique roles of Na+ and other ions as GPCR allosteric modulators. We will also discuss how this knowledge can be applied to the redesign of receptors and ligand probes for desired functional and pharmacological profiles. SIGNIFICANCE STATEMENT: The function and pharmacology of GPCRs strongly depend on the presence of mono and divalent ions in experimental assays and in living organisms. Recent insights into the molecular mechanism of this ion-dependent allosterism from structural, biophysical, biochemical, and computational studies provide quantitative understandings of the pharmacological effects of drugs in vitro and in vivo and open new avenues for the rational design of chemical probes and drug candidates with improved properties.


Asunto(s)
Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Receptores Acoplados a Proteínas G/metabolismo , Sodio/metabolismo , Sitio Alostérico , Aniones/química , Aniones/metabolismo , Sitios de Unión , Cationes Bivalentes/química , Cationes Bivalentes/metabolismo , Cationes Monovalentes/química , Cationes Monovalentes/metabolismo , Cloruros/química , Cloruros/metabolismo , Cristalografía por Rayos X , Humanos , Ligandos , Conformación Proteica , Receptores Acoplados a Proteínas G/química , Sodio/química , Relación Estructura-Actividad , Zinc/química , Zinc/metabolismo
15.
Plant Sci ; 287: 110171, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31481219

RESUMEN

This study was designed to elucidate the physiological responses of two rice genotypes to different pH levels under high saline stress. A salt-tolerant cultivar, FL478, and a salt-sensitive cultivar, IR29, were exposed to saline-alkaline solutions supplemented with 50 mM Na at pH 9 (severe), pH 8 (moderate), and pH 7 (mild) for three weeks. The results indicated that FL478 is relatively saline-alkaline tolerant compared to IR29, and this was evident from its higher dry mass production, lower Na+ concentration in the leaf blades, and maintenance of water balance under both mild and moderate saline-alkaline stress conditions. In both cultivars, Na+ concentrations in the leaf blades were considerably higher at pH 8 than at pH 7, indicating that high alkaline stress promoted Na+ accumulation under highly saline conditions. FL478 plants had lower Na+/K+ ratios in leaf blades and leaf sheaths than IR29 plants under saline-alkaline stress at both pH 7 and pH 8. To understand the mechanisms behind the difference in saline-alkaline tolerance between the two rice genotypes, transcript levels of the genes encoding Na+ transport proteins were analyzed. In response to mild and moderate saline-alkaline stress conditions, salt-tolerant FL478 had highly induced expression of the OsHKT1;5 gene in the roots, corresponding to lower Na+ accumulation in the leaf blades. Induction of high expression of the OsSOS1 gene in the roots of FL478 implied that Na may be effectively exported from cytosols to apoplasts in the roots resulting in sequestration of Na+ to outside of the roots and loading Na+ in xylem transpiration stream. On the other hand, the salt-sensitive IR29 had lower expression of the genes related to Na+ transporters, such as the OsHKT1;5 gene and the OsSOS1 gene, in the roots, leading to higher Na+ accumulation in the shoots. Expression of the determinant genes for alkaline tolerance, such as K+ and Fe acquisition and acidification of the rhizosphere was highly induced in FL478, but not in IR29. Thus, molecular analysis suggested that genes encoding Na+ transport proteins are involved in regulating Na+ transport under saline-alkaline stress in both salt-tolerant and salt-sensitive rice cultivars, and this is useful information for improving saline-alkaline tolerance traits of rice in the future.


Asunto(s)
Oryza/metabolismo , Sodio/metabolismo , Proteínas de Transporte de Catión/metabolismo , Concentración de Iones de Hidrógeno , Oryza/fisiología , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Raíces de Plantas/metabolismo , Brotes de la Planta/metabolismo , Potasio/metabolismo , Estrés Salino
16.
Biochem Soc Trans ; 47(4): 1197-1207, 2019 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-31383819

RESUMEN

Glutamate transporters play important roles in bacteria, archaea and eukaryotes. Their function in the mammalian central nervous system is essential for preventing excitotoxicity, and their dysregulation is implicated in many diseases, such as epilepsy and Alzheimer's. Elucidating their transport mechanism would further the understanding of these transporters and promote drug design as they provide compelling targets for understanding the pathophysiology of diseases and may have a direct role in the treatment of conditions involving glutamate excitotoxicity. This review outlines the insights into the transport cycle, uncoupled chloride conductance and modulation, as well as identifying areas that require further investigation.


Asunto(s)
Sistema de Transporte de Aminoácidos X-AG/metabolismo , Archaea/metabolismo , Sistema de Transporte de Aminoácidos X-AG/química , Ácido Aspártico/metabolismo , Sitios de Unión , Cloruros/metabolismo , Ácido Glutámico/metabolismo , Humanos , Potasio/metabolismo , Conformación Proteica , Sodio/metabolismo
17.
Planta ; 250(5): 1637-1653, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31399792

RESUMEN

MAIN CONCLUSION: The present study shows that salt tolerance in the reproductive stage of rice is primarily governed by the selective Na+ and K+ transport from the root to upper plant parts. Ionic discrimination at the flag leaf, governed by differential expression of Na+- and K+-specific transporters/ion pumps, is associated with reduced spikelet sterility and reproductive stage salt tolerance. Reproductive stage salt tolerance is crucial in rice to guarantee yield under saline condition. In the present study, differential ionic selectivity and the coordinated transport (from root to flag leaf) of Na+ and K+ were investigated to assess their impact on reproductive stage salt tolerance. Four rice genotypes having differential salt sensitivity were subjected to reproductive stage salinity stress in pots. The selective Na+ and K+ transport from the root to upper plant parts was observed in tolerant genotypes. We noticed that prolonged salt exposure did not alter flag leaf greenness even up to 6 weeks; however, it had a detrimental effect on panicle development especially in the salt-susceptible genotype Sabita. But more precise chlorophyll fluorescence imaging analysis revealed salinity-induced damages in Sabita. The salt-tolerant genotype Pokkali (AC41585), a potential Na+ excluder, managed to sequester higher Na+ load in the roots with little upward transport as evident from greater expression of HKT1 and HKT2 transporters. In contrast, the moderately salt-tolerant Lunidhan was less selective in Na+ transport, but possessed a higher capacity to Na+ sequestration in leaves. Higher K+ uptake and tissue-specific redistribution mediated by HAK and AKT transporters showed robust control in selective K+ movement from the root to flag leaf and developing panicles. On the contrary, expressions of Na+-specific transporters in developing panicles were either down-regulated or unaffected in tolerant and moderately tolerant genotypes. Yet, in the panicles of the susceptible genotype Sabita, some of the Na+-specific transporter genes (SOS1, HKT1;5, HKT2;4) were upregulated. Apart from the ionic regulation strategy, cellular energy balance mediated by different plasma-membrane and tonoplastic H+-pumps were also associated with the reproductive stage salt tolerance in rice.


Asunto(s)
Proteínas de Transporte de Catión/metabolismo , Iones/metabolismo , Oryza/fisiología , Potasio/metabolismo , Sodio/metabolismo , Proteínas de Transporte de Catión/genética , Clorofila/metabolismo , Flores/genética , Flores/fisiología , Regulación de la Expresión Génica de las Plantas , Genotipo , Imagen Óptica , Oryza/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reproducción , Salinidad , Tolerancia a la Sal
18.
Environ Pollut ; 254(Pt A): 112971, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31394346

RESUMEN

The effects of exposure to some environmental chemicals on blood pressure have been determined, but the association between non-occupational exposure to perfluoroalkyl substances (PFASs) and blood pressure in adolescents remains unknown. The association between blood pressure and PFAS concentrations was studied by analysing data from 2251 participants filtered from the population enrolled in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2012. After adjusting for age, sex, race, BMI, cotinine level, dietary intake of calcium, caloric intake, sodium consumption, potassium consumption and sampling year, we estimated the coefficients (betas) and 95% confidence intervals (CIs) for the relationship between PFAS concentrations and blood pressure with multiple linear regression models. Potential non-linear relationships were assessed with restricted cubic spline models. Blood levels of perfluorooctane sulfonic acid (PFOS) had a strong positive association with diastolic blood pressure (DBP) in adolescents in the linear model, while the result was not significant in the non-linear model. No significant association was observed between the concentration of any other PFASs and blood pressure. According to the fully adjusted linear regression model (P = 0.041), the mean DBP values in boys in the higher PFOS quintile were 2.70% greater than the mean DBP values of boys in the lowest PFOS quintile. Furthermore, serum PFOS concentrations predominantly affected blood pressure in male adolescents compared with female adolescents. These results provide epidemiological evidence of PFOS-related increases in DBP. Further research is needed to address related issues.


Asunto(s)
Ácidos Alcanesulfónicos/sangre , Presión Sanguínea/efectos de los fármacos , Fluorocarburos/sangre , Hipertensión/inducido químicamente , Adolescente , Calcio/metabolismo , Cotinina/orina , Femenino , Humanos , Modelos Lineales , Masculino , Análisis Multivariante , Encuestas Nutricionales , Potasio/metabolismo , Factores Sexuales , Sodio/metabolismo
19.
BMC Plant Biol ; 19(1): 357, 2019 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-31419943

RESUMEN

BACKGROUND: Survival of plants in response to salinity stress is typically related to Na+ toxicity, but little is known about how heterologous high-affinity potassium transporter (HKT) may help alleviate salt-induced damages in potato (Solanum tuberosum L.). RESULTS: In this study, we used the Arabidopsis thaliana high-affinity potassium transporter gene (AtHKT1) to enhance the capacity of potato plants to tolerate salinity stress by decreasing Na+ content and improving K+/Na+ ratio in plant leaves, while maintaining osmotic balance. Seven AtHKT1 transformed potato lines (namely T1, T2, T3, T5, T11, T13 and T15) were compared with non-transgenic control plant at molecule and whole-plant levels. The lines T3 and T13 had the highest AtHKT1 expression with the tolerance index (an quantitative assessment) being 6.8 times that of the control. At 30 days under 100 and 150 mmol L- 1 NaCl stress treatments, the T3 and T13 lines had least reductions in net photosynthetic rate, stomatal conductance and transpiration rate among the seven lines, leading to the increased water use efficiency and decreased yield loss. CONCLUSIONS: We conclude that the constitutive overexpression of AtHKT1 reduces Na+ accumulation in potato leaves and promotes the K+/Na+ homeostasis that minimizes osmotic imbalance, maintains photosynthesis and stomatal conductance, and increases plant productivity.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas de Transporte de Catión/genética , Expresión Génica , Tolerancia a la Sal/genética , Solanum tuberosum/fisiología , Simportadores/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte de Catión/metabolismo , Homeostasis , Hojas de la Planta/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/fisiología , Potasio/metabolismo , Sodio/metabolismo , Solanum tuberosum/genética , Simportadores/metabolismo
20.
Aquat Toxicol ; 215: 105283, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31470336

RESUMEN

Recent studies have demonstrated that white sturgeon are more sensitive to acute exposure to Cu than rainbow trout (Oncorhynchus mykiss), especially during early life-stages. However, the physiological mechanisms underlying this difference in sensitivity to Cu is not known. In the present study, we first confirmed the higher sensitivity (lower 96 h LC50 values) of white sturgeon to Cu at three different life stages (larva, swim-up, and juvenile) relative to their counterparts in rainbow trout. We also demonstrated that acute exposure to Cu (50 µg/L for 4.5 h) caused a significantly greater reduction in the rate of waterborne Na uptake in white sturgeon relative to that in rainbow trout across all three life-stages. In agreement with this observation, we also found that acute exposure to Cu (20 µg/L for 48 h) elicits a significantly greater decrease in whole body Na level in all life stages of white sturgeon compared to rainbow trout. In contrast, white sturgeon demonstrated a higher or similar level of Cu body burden relative to rainbow trout during acute Cu exposure (20 µg/L for 24 h), thereby indicating that Cu bioaccumulation is not a good indicator of its toxicity in these species. Overall, our study demonstrated that the differences in sensitivity to acute Cu exposure between white sturgeon and rainbow trout can be explained on the basis of differential effects of Cu on Na homeostasis.


Asunto(s)
Cobre/toxicidad , Peces/fisiología , Homeostasis/efectos de los fármacos , Oncorhynchus mykiss/fisiología , Sodio/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Exposición a Riesgos Ambientales , Dosificación Letal Mediana , Oncorhynchus mykiss/sangre , ATPasas de Translocación de Protón/metabolismo , Sodio/sangre , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Pruebas de Toxicidad Aguda , Calidad del Agua
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