Variation potential induces decreased PSI damage and increased PSII damage under high external temperatures in pea

2015 ◽  
Vol 42 (8) ◽  
pp. 727 ◽  
Author(s):  
Vladimir Sukhov ◽  
Lyubov Surova ◽  
Oksana Sherstneva ◽  
Albina Bushueva ◽  
Vladimir Vodeneev
Keyword(s):  
Thermal Resistance ◽  
Electrical Signal ◽  
Photosynthetic Parameters ◽  
Strongly Correlated ◽  
Functional Responses ◽  
External Temperature ◽  
Variation Potential ◽  
Whole Plant ◽  
Local Burning ◽  
Stimulation Of

Local burning of a leaf induces a unique electrical signal in plants: variation potential (VP), which can cause numerous functional responses, including changes in photosynthesis. The influences of VP on damage to photosynthetic machinery and thermal resistance of whole plant with heating were investigated in pea (Pisum sativum L.). Under high external temperature (53°C), VP induction was found to cause accelerated initial lowering of photosynthetic parameters, reduced transpiration rate, decreased PSI damage, and increased PSII damage. Increased PSI resistance was in good accordance with our previous data, but VP-induced stimulation of PSII damage under heating required further analysis. The magnitudes of leaf heating in experiments and controls were found to be different (~46−48°C after VP and ~44−45°C without it) under identical external temperatures and were connected with different transpiration rates under these conditions. Also PSII damage and the magnitude of leaf heating were strongly correlated. As a result, it was supposed that leaf temperature contributed to VP-induced stimulation of PSII damage with heating. Investigation of VP’s influence on pea growth after heating showed that the electrical signal decreased plant growth suppression after heating (i.e. VP-induced increases in PSII damage did not noticeably influence thermal resistance in the whole plant).

scholarly journals A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 372
Author(s):  
Ekaterina Sukhova ◽  
Elena Akinchits ◽  
Sergey V. Gudkov ◽  
Roman Y. Pishchalnikov ◽  
Vladimir Vodeneev ◽  
...  
Keyword(s):  
Higher Plants ◽  
Initial Point ◽  
Electrical Signal ◽  
Terminal Point ◽  
Hydraulic Pressure ◽  
Long Distance ◽  
Variation Potential ◽  
Damaged Zone ◽  
Pressure Dynamics ◽  
The Impact

Variation potential (VP) is an important long-distance electrical signal in higher plants that is induced by local damages, influences numerous physiological processes, and participates in plant adaptation to stressors. The transmission of increased hydraulic pressure through xylem vessels is the probable mechanism of VP propagation in plants; however, the rates of the pressure transmission and VP propagation can strongly vary. We analyzed this problem on the basis of a simple mathematical model of the pressure distribution along a xylem vessel, which was approximated by a tube with a pressure gradient. It is assumed that the VP is initiated if the integral over pressure is more than a threshold one, taking into account that the pressure is transiently increased in the initial point of the tube and is kept constant in the terminal point. It was shown that this simple model can well describe the parameters of VP propagation in higher plants, including the increase in time before VP initiation and the decrease in the rate of VP propagation with an increase in the distance from the zone of damage. Considering three types of the pressure dynamics, our model predicts that the velocity of VP propagation can be stimulated by an increase in the length of a plant shoot and also depends on pressure dynamics in the damaged zone. Our results theoretically support the hypothesis about the impact of pressure variations in xylem vessels on VP propagation.

scholarly journals Electro-haptic hearing: Speech-in-noise performance in cochlear implant users is enhanced by tactile stimulation of the wrists

2019 ◽  
Author(s):  
Mark D. Fletcher ◽  
Amatullah Hadeedi ◽  
Tobias Goehring ◽  
Sean R Mills
Keyword(s):  
Cochlear Implant ◽  
Speech Intelligibility ◽  
Tactile Stimulation ◽  
Electrical Signal ◽  
Noise Performance ◽  
Speech In Noise ◽  
Non Invasive ◽  
Real World Application ◽  
Before And After ◽  
Stimulation Of

Cochlear implant (CI) users receive only limited sound information through their implant, which means that they struggle to understand speech in noisy environments. Recent work has suggested that combining the electrical signal from the CI with a haptic signal that provides crucial missing sound information (“electro-haptic stimulation”; EHS) could improve speech-in-noise performance. The aim of the current study was to test whether EHS could enhance speech-in-noise performance in CI users using: (1) a tactile signal derived using an algorithm that could be applied in real time, (2) a stimulation site appropriate for a real-world application, and (3) a tactile signal that could readily be produced by a compact, portable device. We measured speech intelligibility in multi-talker noise with and without vibro-tactile stimulation of the wrist in CI users, before and after a short training regime. No effect of EHS was found before training, but after training EHS was found to improve the number of words correctly identified by an average of 8.3 %-points, with some users improving by more than 20 %-points. Our approach could offer an inexpensive and non-invasive means of improving speech-in-noise performance in CI users.

scholarly journals Hormesis in Plants: The Role of Oxidative Stress, Auxins and Photosynthesis in Corn Treated with Cd or Pb

2020 ◽  
Vol 21 (6) ◽  
pp. 2099 ◽  
Author(s):  
Eugeniusz Małkowski ◽  
Krzysztof Sitko ◽  
Michał Szopiński ◽  
Żaneta Gieroń ◽  
Marta Pogrzeba ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Shoot Growth ◽  
Photosynthetic Apparatus ◽  
Growth Stimulation ◽  
Photosynthetic Parameters ◽  
Toxic Substances ◽  
Wide Range ◽  
The Common ◽  
Stimulation Of

Hormesis, which describes the stimulatory effect of low doses of toxic substances on growth, is a well-known phenomenon in the plant and animal kingdoms. However, the mechanisms that are involved in this phenomenon are still poorly understood. We performed preliminary studies on corn coleoptile sections, which showed a positive correlation between the stimulation of growth by Cd or Pb and an increase in the auxin and H2O2 content in the coleoptile sections. Subsequently, we grew corn seedlings in hydroponic culture and tested a wide range of Cd or Pb concentrations in order to determine hormetic growth stimulation. In these seedlings the gas exchange and the chlorophyll a fluorescence, as well as the content of chlorophyll, flavonol, auxin and hydrogen peroxide, were measured. We found that during the hormetic stimulation of growth, the response of the photosynthetic apparatus to Cd and Pb differed significantly. While the application of Cd mostly caused a decrease in various photosynthetic parameters, the application of Pb stimulated some of them. Nevertheless, we discovered that the common features of the hormetic stimulation of shoot growth by heavy metals are an increase in the auxin and flavonol content and the maintenance of hydrogen peroxide at the same level as the control plants.

scholarly journals Synbiotic Supplementation Containing Whole Plant Sugar Cane Fibre and Probiotic Spores Potentiates Protective Synergistic Effects in Mouse Model of IBD

Nutrients ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 818 ◽  
Author(s):  
Tanvi Shinde ◽  
Agampodi Promoda Perera ◽  
Ravichandra Vemuri ◽  
Shakuntla V. Gondalia ◽  
Avinash V. Karpe ◽  
...  
Keyword(s):  
Sugar Cane ◽  
Activity Index ◽  
Synergistic Effects ◽  
Disease Activity Index ◽  
Bacillus Coagulans ◽  
Short Chain Fatty Acids ◽  
Chow Diet ◽  
Whole Plant ◽  
Synbiotic Supplementation ◽  
Stimulation Of

Inflammatory bowel diseases (IBD) are a chronic inflammatory disorders with increasing global incidence. Synbiotic, which is a two-point approach carrying probiotic and prebiotic components in mitigating inflammation in IBD, is thought to be a pragmatic approach owing to the synergistic outcomes. In this study, the impacts of dietary supplementation with probiotic Bacillus coagulans MTCC5856 spores (B. coagulans) and prebiotic whole plant sugar cane fibre (PSCF) was assessed using a murine model of IBD. Eight-week-old C57BL/6 mice were fed a normal chow diet supplemented with either B. coagulans, PSCF or its synbiotic combination. After seven days of supplementation, colitis was induced with dextran sulfate sodium (DSS) in drinking water for seven days during the continuation of the supplemented diets. Synbiotic supplementation ameliorated disease activity index and histological score (−72%, 7.38, respectively), more effectively than either B. coagulans (−47%, 10.1) and PSCF (−53%, 13.0) alone. Synbiotic supplementation also significantly (p < 0.0001) prevented the expression of tight junction proteins and modulated the altered serum IL-1β (−40%), IL-10 (+26%), and C-reactive protein (CRP) (−39%) levels. Synbiotic supplementations also raised the short-chain fatty acids (SCFA) profile more extensively compared to the unsupplemented DSS-control. The synbiotic health outcome effect of the probiotic and prebiotic combinations may be associated with a synergistic direct immune-regulating efficacy of the components, their ability to protect epithelial integrity, stimulation of probiotic spores by the prebiotic fibre, and/or with stimulation of greater levels of fermentation of fibres releasing SCFAs that mediate the reduction in colonic inflammation. Our model findings suggest synbiotic supplementation should be tested in clinical trials.

scholarly journals Hypothalamic circuitry underlying stress-induced insomnia and peripheral immunosuppression

2020 ◽  
Vol 6 (37) ◽  
pp. eabc2590 ◽  
Author(s):  
Shi-Bin Li ◽  
Jeremy C. Borniger ◽  
Hiroshi Yamaguchi ◽  
Julien Hédou ◽  
Brice Gaudilliere ◽  
...  
Keyword(s):  
Restraint Stress ◽  
Immune Cell ◽  
Cell Mass ◽  
Neural Substrates ◽  
Functional Responses ◽  
Genetic Ablation ◽  
Optogenetic Stimulation ◽  
Response To Stress ◽  
Paraventricular Nucleus Of Hypothalamus ◽  
Stimulation Of

The neural substrates of insomnia/hyperarousal induced by stress remain unknown. Here, we show that restraint stress leads to hyperarousal associated with strong activation of corticotropin-releasing hormone neurons in the paraventricular nucleus of hypothalamus (CRHPVN) and hypocretin neurons in the lateral hypothalamus (HcrtLH). CRHPVN neurons directly innervate HcrtLH neurons, and optogenetic stimulation of LH-projecting CRHPVN neurons elicits hyperarousal. CRISPR-Cas9–mediated knockdown of the crh gene in CRHPVN neurons abolishes hyperarousal induced by stimulating LH-projecting CRHPVN neurons. Genetic ablation of Hcrt neurons or crh gene knockdown significantly counteracts restraint stress–induced hyperarousal. Single-cell mass cytometry by time of flight (CyTOF) revealed extensive changes to immune cell distribution and functional responses in peripheral blood during hyperarousal upon optogenetic stimulation of CRHPVN neurons simulating stress-induced insomnia. Our findings suggest both central and peripheral systems are synergistically engaged in the response to stress via CRHPVN circuitry.

scholarly journals Characterization of Prejunctional Muscarinic Receptors: Effects on the Release of VIP and Functional Responses and Receptor Expression in the Ovine Submandibular Gland

2009 ◽  
Vol 2009 ◽  
pp. 1-6
Author(s):  
Anders T. Ryberg ◽  
Ondrej Soukup ◽  
Gunnar Tobin
Keyword(s):  
Electrical Stimulation ◽  
Submandibular Gland ◽  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Receptor Expression ◽  
Receptor Subtypes ◽  
Chorda Tympani Nerve ◽  
Functional Responses ◽  
Stimulation Of

In the in vivo experiments on anaesthetized sheep, it was presently examined whether muscarinic receptor antagonists with diverse selectivity affect the release of VIP in response to electrical stimulation of the parasympathetic chorda tympanic nerve differently, and if the changes in the release could be associated to altered secretory and vasodilator responses. The location of the muscarinic receptor subtypes was examined also. In the experiments, blood was collected out of the submandibular venous drainage before and during electrical stimulation of chorda tympani nerve in the absence and presence either of pirenzepine or methoctramine. While metchoctramine increased the output of protein, pirenzepine inhibited flow of saliva and increased protein output, vasodilatation, and VIP output. In morphological examinations, the inhibitory muscarinic M4 receptor occurred interacinarily in the gland. It is concluded that prejunctional muscarinic receptors, most likely of the M4 subtype, exert inhibitory modulation of the parasympathetic release of VIP in the ovine submandibular gland.

scholarly journals Structural and functional responses of Carex aquatilis to increasing sodium concentrations

2020 ◽  
Vol 28 (5) ◽  
pp. 753-763
Author(s):  
Dale H. Vitt ◽  
Lilyan C. Glaeser ◽  
Melissa House ◽  
Samantha P. Kitchen
Keyword(s):  
Oil Sands ◽  
Belowground Biomass ◽  
Water Levels ◽  
Strongly Correlated ◽  
Functional Responses ◽  
Carex Aquatilis ◽  
Athabasca Oil Sands Region ◽  
Threshold Response ◽  
Brackish Marshes ◽  
High Concentrations

Abstract Carex aquatilis is a widespread boreal species that is abundant in open fens and marshes. The species has broad natural tolerances to differing water levels and ion concentrations including occurrences in brackish marshes but not sodic wetlands. Sandhill Wetland, constructed on Syncrude Canada Ltd. mineral surface lease in the Athabasca Oil Sands Region, is a research site that was engineered to support a self-sustaining wetland. The site is currently in its eighth year post wet-up and is partially dominated by C. aquatilis. Increasing Na+ concentrations in the porewaters at Sandhill Wetland are an on-going concern for the performance of the existing plant communities. Here we examine the responses of C. aquatilis to an increasing regime of sodium carried out in a greenhouse experiment. We posed three questions for this experiment: (1) is there a threshold response for performance of C. aquatilis to increasing sodium, (2) if so, does it occur in the range of sodium that is present at current reclamation programs, and (3) is C. aquatilis resistant to high concentrations of sodium? Carex aquatilis survived all treatment concentrations of sodium including the highest treatment of 2354 mg L− 1. In general, both structural and functional attributes of C. aquatilis did not differ between the 17 and 1079 mg L− 1 treatments; however, performances of all attributes were reduced in the 2354 mg L− 1 treatment. Belowground biomass had greater decreases compared to aboveground components, including both biomass and photosynthesis. The aboveground decreases in performance were associated with exclusion of sodium from the aboveground components by the belowground components. Reduction in photosynthesis was strongly correlated with reduced stomatal conductance and lower transpiration. Although C. aquatilis demonstrated a wide tolerance to sodium concentrations, a clear threshold was present between 1079 and 2354 mg L− 1. These decreases in performance in our greenhouse trials were at levels currently present at Sandhill Wetland, and careful assessment of sodium concentrations in the near future needs to be continued.

scholarly journals Novel active method for the estimation of a building wall thermal resistance

2020 ◽  
Vol 172 ◽  
pp. 14008
Author(s):  
Adrien François ◽  
Laurent Ibos ◽  
Vincent Feuillet ◽  
Johann Meulemans
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Building Materials ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Heat Fluxes ◽  
External Temperature ◽  
Building Wall ◽  
High Thermal Inertia

The thermal resistance of a wall can be readily measured in steady-state. However, such a state is seldomly achieved in a building because of the variation of outdoor conditions as well as the high thermal inertia of building materials. This paper introduces a novel active (dynamic) method to measure the thermal resistance of a building wall. Not only are active approaches less sensitive to external temperature variations, they also enable to perform measurements within only a few hours. In the proposed methodology, an artificial thermal load is applied to a wall (heating of the indoor air) and its thermal response is monitored. Inverse techniques are used with a reduced model to estimate the value of the thermal resistance of a wall from the measured temperatures and heat fluxes. The methodology was validated on a known load-bearing wall built inside a climate chamber. The results were in good agreement with reference values derived from a steady-state characterization of the wall. The method also demonstrated a good reproducibility.

Effect of Delaying Addition of Heat Stimulated Superplasticizer on Fresh Properties of Mortar

2017 ◽  
Vol 890 ◽  
pp. 396-400 ◽  
Author(s):  
Zabihollah Tahery ◽  
Faraidoon Rahmanzai ◽  
Shigeyuki Date
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Mortar ◽  
Polycarboxylic Acid ◽  
Fresh Properties ◽  
External Temperature ◽  
Factors Affecting ◽  
Air Content ◽  
Heat Stimulation ◽  
Stimulation Of

To assure the quality and required workability of mortar or concrete, various types of superplasticizers are used. There are many factors affecting the performance of superplasticizers explicitly, type and dosage of the superplasticizers, type of cement, temperature and mixing procedure, as well as the addition times of the superplasticizers. Some researchers investigated the effect of delaying the addition time of superplasticizer to mortar or concrete, but there is not enough data about the effect of external temperature on performance of superplasticizers and consequent influences on fresh properties of mortar or concrete. In this research the effect of delaying the addition time of superplasticizers and influence of external temperature, namely, heat stimulation of superplasticizers, on fluidity, fresh density and air content of fresh cement mortar was investigated. Two types of Precast and Ready-Mix of Polycarboxylic acid-based ether superplasticizers with Ordinary Portland Cement was used. Delaying the addition time of superplasticizers enhanced the fluidity, slightly decreased the fresh density and increased the air content of mortar in comparison with simultaneous addition time with both heated and non-heated Superplasticizers.

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