scholarly journals Nanoparticles and Nanomaterials as Plant Biostimulants

2018 ◽  
Author(s):  
Antonio Juárez-Maldonado ◽  
Hortensia Ortega-Ortíz ◽  
América Berenice Morales-Díaz ◽  
Susana González-Morales ◽  
Álvaro Morelos-Moreno ◽  
...  
Keyword(s):  
Plant Growth ◽  
Cell Walls ◽  
Cellular Response ◽  
Small Volume ◽  
Electrical Potential ◽  
High Density ◽  
Surface Charges ◽  
Electrical Potentials ◽  
Transmembrane Electrical Potential ◽  
Integral Proteins

Biostimulants are materials that when applied in small amounts are capable of promoting plant growth. Nanoparticles (NPs) and nanomaterials (NMs) can be considered as biostimulants since, in specific ranges of concentration, generally in small levels, they increase the plant growth. Pristine NPs and NMS have a high density of surface charges capable of unspecific interactions with the surface charges of the cell walls and membranes of plant cells. In the same way, the functionalized NPs and NMS, and the NPs and NMs with a corona formed after the exposition to natural fluids such as water, soil solution, or the interior of organisms, presents a high density of surface charges that interact with specific charged groups in cell surfaces. The magnitude of the interaction will depend on the materials adhered to the corona, but the high-density charges located in a small volume causes an intense interaction capable of disturbing the density of surface charges of cell walls and membranes. The electrostatic disturbance can have an impact on the electrical potentials of the outer and inner surfaces, as well as on the transmembrane electrical potential, modifying the activity of the integral proteins of the membranes. The extension of the cellular response can range from biostimulation to cell death and will depend on the concentration, size, and the characteristics of the corona.

scholarly journals Nanoparticles and Nanomaterials as Plant Biostimulants

2019 ◽  
Vol 20 (1) ◽  
pp. 162 ◽  
Author(s):  
Antonio Juárez-Maldonado ◽  
Hortensia Ortega-Ortíz ◽  
América Berenice Morales-Díaz ◽  
Susana González-Morales ◽  
Álvaro Morelos-Moreno ◽  
...  
Keyword(s):  
Plant Growth ◽  
Cell Walls ◽  
Cellular Response ◽  
Small Volume ◽  
Electrical Potential ◽  
High Density ◽  
Surface Charges ◽  
Electrical Potentials ◽  
Transmembrane Electrical Potential ◽  
Integral Proteins

Biostimulants are materials that when applied in small amounts are capable of promoting plant growth. Nanoparticles (NPs) and nanomaterials (NMs) can be considered as biostimulants since, in specific ranges of concentration, generally in small levels, they increase plant growth. Pristine NPs and NMs have a high density of surface charges capable of unspecific interactions with the surface charges of the cell walls and membranes of plant cells. In the same way, functionalized NPs and NMs, and the NPs and NMs with a corona formed after the exposition to natural fluids such as water, soil solution, or the interior of organisms, present a high density of surface charges that interact with specific charged groups in cell surfaces. The magnitude of the interaction will depend on the materials adhered to the corona, but high-density charges located in a small volume cause an intense interaction capable of disturbing the density of surface charges of cell walls and membranes. The electrostatic disturbance can have an impact on the electrical potentials of the outer and inner surfaces, as well as on the transmembrane electrical potential, modifying the activity of the integral proteins of the membranes. The extension of the cellular response can range from biostimulation to cell death and will depend on the concentration, size, and the characteristics of the corona.

scholarly journals Triboelectrochemistry: Influence of Applied Electrical Potentials on Friction and Wear of Lubricated Contacts

2020 ◽  
Vol 68 (3) ◽  
Author(s):  
Hugh A. Spikes
Keyword(s):  
Friction And Wear ◽  
Electrical Potential ◽  
Lubricant Additives ◽  
Fluid Interfaces ◽  
Surface Charges ◽  
Counter Electrodes ◽  
Electrical Potentials ◽  
Tribological Surfaces ◽  
Electrode Potentials ◽  
Electrical Conductivities

Abstract Research on the effects of applied electrical potential on friction and wear, a topic sometimes termed “Triboelectrochemistry”, has been reviewed. Historically, most such research has focussed on aqueous lubricants, whose relatively high electrical conductivities enable use of three-electrode electrochemical kinetic techniques, in which the electrode potential at a single electrode | fluid interface is controlled relative to a suitable reference electrode. This has led to identification of several different mechanisms by which applied electrode potentials can influence friction and wear. Of these, the most practically important are: (i) promotion of adsorption/desorption of polar additives on tribological surfaces by controlling the latters’ surface charges; (ii) stimulation or suppression of redox reactions involving either oxygen or lubricant additives at tribological surfaces. In recent years, there has been growing interest in the effects of applied electrical potentials on rubbing contacts lubricated by non-aqueous lubricants, such as ester- and hydrocarbon-based oils. Two different approaches have been used to study this. In one, a DC potential difference in the mV to V range is applied directly across a thin film, lubricated contact to form a pair of electrode | fluid interfaces. This has been found to promote some additive reactions and to influence friction and wear. However, little systematic exploration has been reported of the underlying processes and generally the electrode potentials at the interfaces have not been well defined. The second approach is to increase the conductivity of non-aqueous lubricants by adding secondary electrolytes and/or using micro/nanoscale electrodes, to enable the use of three-electrode electrochemical methods at single metal | fluid interfaces, with reference and counter electrodes. A recent development has been the introduction of ionic liquids as both base fluids and lubricant additives. These have relatively high electrical conductivities, allowing control of applied electrode potentials of individual metal | fluid interfaces, again with reference and counter electrodes. The broadening use of “green”, aqueous-based lubricants also enlarges the possible future scope of applied electrode potentials in tribology. From research to date, there would appear to be considerable opportunities for using applied electrical potentials both to promote desirable and to supress unwanted lubricant interactions with rubbing surfaces, thereby improving the tribological performance of lubricated machine components. Graphical Abstract

scholarly journals The strain-generated electrical potential in cartilaginous tissues: a role for piezoelectricity

2021 ◽  
Vol 13 (1) ◽  
pp. 91-100
Author(s):  
Philip Poillot ◽  
Christine L. Le Maitre ◽  
Jacques M. Huyghe
Keyword(s):  
Physiological Response ◽  
Numerical Models ◽  
Measurement Techniques ◽  
Electrical Potential ◽  
Evidence Base ◽  
Piezoelectric Response ◽  
Mechanical Forces ◽  
Streaming Potentials ◽  
Cartilaginous Tissues ◽  
Electrical Potentials

AbstractThe strain-generated potential (SGP) is a well-established mechanism in cartilaginous tissues whereby mechanical forces generate electrical potentials. In articular cartilage (AC) and the intervertebral disc (IVD), studies on the SGP have focused on fluid- and ionic-driven effects, namely Donnan, diffusion and streaming potentials. However, recent evidence has indicated a direct coupling between strain and electrical potential. Piezoelectricity is one such mechanism whereby deformation of most biological structures, like collagen, can directly generate an electrical potential. In this review, the SGP in AC and the IVD will be revisited in light of piezoelectricity and mechanotransduction. While the evidence base for physiologically significant piezoelectric responses in tissue is lacking, difficulties in quantifying the physiological response and imperfect measurement techniques may have underestimated the property. Hindering our understanding of the SGP further, numerical models to-date have negated ferroelectric effects in the SGP and have utilised classic Donnan theory that, as evidence argues, may be oversimplified. Moreover, changes in the SGP with degeneration due to an altered extracellular matrix (ECM) indicate that the significance of ionic-driven mechanisms may diminish relative to the piezoelectric response. The SGP, and these mechanisms behind it, are finally discussed in relation to the cell response.

Effects of air discharge on surface charges and cell walls of Fusarium oxysporum

2021 ◽  
Author(s):  
Mengdie Liu ◽  
Hui Tang ◽  
Huiwen Jiang ◽  
Jie Li ◽  
Shoulei Yan ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Cell Walls ◽  
Surface Charges ◽  
Air Discharge

The mitochondrial consequences of uncoupling intact cells depend on the nature of the exogenous substrate

2001 ◽  
Vol 355 (1) ◽  
pp. 231-235 ◽  
Author(s):  
Brigitte SIBILLE ◽  
Céline FILIPPI ◽  
Marie-Astrid PIQUET ◽  
Pascale LECLERCQ ◽  
Eric FONTAINE ◽  
...  
Keyword(s):  
Oxidation Rate ◽  
Marked Decrease ◽  
Electrical Potential ◽  
Atp Synthesis ◽  
Intact Cells ◽  
Isolated Mitochondria ◽  
Exogenous Substrate ◽  
High Oxidation ◽  
Transmembrane Electrical Potential ◽  
Sustained Increase

In isolated mitochondria the consequences of oxidative phosphorylation uncoupling are well defined, whereas in intact cells various effects have been described. Uncoupling liver cells with 2,4-dinitrophenol (DNP) in the presence of dihydroxyacetone (DHA) and ethanol results in a marked decrease in mitochondrial transmembrane electrical potential (∆ψ), ATP/ADP ratios and gluconeogenesis (as an ATP-utilizing process), whereas the increased oxidation rate is limited and transient. Conversely, when DHA is associated with octanoate or proline, DNP addition results in a very large and sustained increase in oxidation rate, whereas the decreases in ∆ψ, ATP/ADP ratios and gluconeogenesis are significantly less when compared with DHA and ethanol. Hence significant energy wastage (high oxidation rate) by uncoupling is achieved only with substrates that are directly oxidized in the mitochondrial matrix. Conversely in the presence of substrates that are first oxidized in the cytosol, uncoupling results in a profound decrease in mitochondrial ∆ψ and ATP synthesis, whereas energy wastage is very limited.

Understanding the electrical behavior of the action potential in terms of elementary electrical sources

2015 ◽  
Vol 39 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Javier Rodriguez-Falces
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Present Report ◽  
Electrical Potential ◽  
Ionic Currents ◽  
New Approach ◽  
Electrical Potentials ◽  
Proposed Model ◽  
Ionic Mechanisms ◽  
Human Electrophysiology

A concept of major importance in human electrophysiology studies is the process by which activation of an excitable cell results in a rapid rise and fall of the electrical membrane potential, the so-called action potential. Hodgkin and Huxley proposed a model to explain the ionic mechanisms underlying the formation of action potentials. However, this model is unsuitably complex for teaching purposes. In addition, the Hodgkin and Huxley approach describes the shape of the action potential only in terms of ionic currents, i.e., it is unable to explain the electrical significance of the action potential or describe the electrical field arising from this source using basic concepts of electromagnetic theory. The goal of the present report was to propose a new model to describe the electrical behaviour of the action potential in terms of elementary electrical sources (in particular, dipoles). The efficacy of this model was tested through a closed-book written exam. The proposed model increased the ability of students to appreciate the distributed character of the action potential and also to recognize that this source spreads out along the fiber as function of space. In addition, the new approach allowed students to realize that the amplitude and sign of the extracellular electrical potential arising from the action potential are determined by the spatial derivative of this intracellular source. The proposed model, which incorporates intuitive graphical representations, has improved students' understanding of the electrical potentials generated by bioelectrical sources and has heightened their interest in bioelectricity.

The Effect of External Potassium Ions on the Electrical Potential Measured Across the Gills of the Teleost, Dormitator Maculatus

1974 ◽  
Vol 61 (2) ◽  
pp. 277-283
Author(s):  
DAVID H. EVANS ◽  
JEFFREY C. CARRIER ◽  
MARGARET B. BOGAN
Keyword(s):  
Sea Water ◽  
Electrical Potential ◽  
Potassium Ions ◽  
Sodium Efflux ◽  
Electrical Potentials ◽  
External Potassium ◽  
Potassium Influx ◽  
Sodium Extrusion ◽  
Sufficient Magnitude ◽  
Stimulation Of

1. A technique has been developed for the measurement of electrical potentials (TGP's) across the gills of free-swimming, Dormitator maculatus. 2. Transfer of fish to various KCl solutions is correlated with changes in the TGP, which are not of sufficient magnitude to account for the known potassium stimulation of sodium efflux from this species. 3. Transfer to potassium-free sea water results in little or no change in TGP while previous results have shown that such a transfer is correlated with a 22% reduction of sodium efflux. 4. Transfer to fresh water results in a reduction of TGP from +17 mV (inside positive) to -36 mV which is sufficient to account for the instantaneous reduction in sodium efflux previously shown for this species. 5. It is concluded that while changes in TGP can account for the ‘Na-free effect’ in D. maculatus they cannot account for the potassium effects on sodium extrusion. This supports the previous conclusion that sodium efflux and potassium influx are chemically linked in this species.

Phosphate transport in kidneys: effect of transmembrane electrical potential

1991 ◽  
Vol 261 (4) ◽  
pp. F663-F669 ◽  
Author(s):  
R. Beliveau ◽  
J. Strevey
Keyword(s):  
Driving Force ◽  
Transmembrane Potential ◽  
Electrical Potential ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Saturation Curve ◽  
Maximal Velocity ◽  
Transmembrane Electrical Potential ◽  
The Hill ◽  
Phosphate Influx

The effect of a transmembrane electrical potential on phosphate transport by kidney brush-border membrane vesicles was studied. The initial rate of Na(+)-dependent phosphate influx was twice as high as that of efflux. Generation of a negative transmembrane potential had a stimulatory effect on the rate of influx but had no effect on efflux. The Na+ saturation curve for phosphate influx was sigmoidal, and the Hill coefficients were similar, in the presence and absence of a transmembrane potential. The membrane potential increased both the affinity for phosphate and the maximal velocity (Vmax) of the transporter. In the absence of a Na+ gradient, the stimulation by the potential was 1.78-fold. When a proton gradient (in greater than out) was the driving force, the electrical potential stimulated phosphate transport 1.71-fold. Internal Na+ (trans) inhibited phosphate influx whether a potential was present or not. Internal phosphate (trans) stimulated phosphate influx in the absence of a potential but not in its presence. These results indicate that the electrical potential is an important driving force for the Na(+)-phosphate carrier and that the translocation of the carrier is a potential-dependent step.

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