scholarly journals Role of salicylic acid in acclimation to low temperature

2013 ◽  
Vol 61 (2) ◽  
pp. 161-172 ◽  
Author(s):  
M. Pál ◽  
O. Gondor ◽  
T. Janda
Keyword(s):  
Salicylic Acid ◽  
Low Temperature ◽  
Plant Species ◽  
Membrane Integrity ◽  
Stress Factors ◽  
Limiting Factors ◽  
Wide Range ◽  
Metabolic Reactions ◽  
Related Compounds

Low temperature is one of the most important limiting factors for plant growth throughout the world. Exposure to low temperature may cause various phenotypic and physiological symptoms, and may result in oxidative stress, leading to loss of membrane integrity and to the impairment of photosynthesis and general metabolic processes. Salicylic acid (SA), a phenolic compound produced by a wide range of plant species, may participate in many physiological and metabolic reactions in plants. It has been shown that exogenous SA may provide protection against low temperature injury in various plant species, while various stress factors may also modify the synthesis and metabolism of SA. In the present review, recent results on the effects of SA and related compounds in processes leading to acclimation to low temperatures will be discussed.

scholarly journals Silacyclohexanes, Sila(hetero)cyclohexanes and Related Compounds: Structure and Conformational Analysis

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1624 ◽  
Author(s):  
Bagrat A. Shainyan
Keyword(s):  
Nmr Spectroscopy ◽  
Electron Diffraction ◽  
Low Temperature ◽  
Conformational Analysis ◽  
Gas Phase ◽  
Theoretical Calculations ◽  
Gas Electron Diffraction ◽  
Experimental Measurements ◽  
Related Compounds

Conformational analysis of Si-mono- and Si,Si-disubstituted silacyclohexanes as well as their analogues with a heteroatom(s) in the ring is reviewed with the focus on the recent results. Experimental measurements in the gas phase (gas electron diffraction, GED) and low temperature NMR spectroscopy (LT NMR) on 1H, 13C and 29Si nuclei are described along with theoretical calculations at the DFT and MP2 levels of theory. Structural and conformational specific features are shown to be principally different from those of the carbon predecessors—the corresponding cyclohexanes, oxanes, thianes and piperidines. The role of various effects (steric, hyperconjugation, stereoelectronic, electrostatic) is demonstrated.

Quantum Diffusion of H(D) In Semiconductors and Metals, and The Role of the Interaction with Impurities

1998 ◽  
Vol 513 ◽  
Author(s):  
G. Cannelli ◽  
R. Cantelli ◽  
F. Cordero ◽  
E. Giovine ◽  
F. Trequattrini
Keyword(s):  
Low Temperature ◽  
Energy Levels ◽  
Relaxation Rates ◽  
Doped Semiconductors ◽  
Higher Symmetry ◽  
Boron Doped ◽  
Wide Range ◽  
Diffusion Studies ◽  
Tunnel System

ABSTRACTThe mobility of hydrogen and its isotopes in metals has been the object of investigation for several years, whereas the diffusion studies of H in doped semiconductors started more recently. Although the H diffusion coefficient in metals may be several orders of magnitudes higher than in semiconductors, the dynamics of H in metals and semiconductors presents many common features, like precipitation, trapping by heavier impurities and, as indicated by recent results, quantum tunneling at low temperature.In boron doped silicon, the relaxation rates τ−1(T) of H around B obtained from anelastic relaxation were joined with those from infrared absorption: the remarkably wide range obtained (11 decades) clearly shows a deviation of τ−1(T) from the classical dependence at low temperature. However, the results obtained and their analysis do not allow yet to draw conclusions on the mechanism governing the H(D) dynamics.Recently, the investigation of the dynamics of H(D) in GaAs doped with Zn revealed a dissipation peak at 20 K in the kHz range. This relaxation has the highest rate found for H in a semiconductor: more than 15 orders of magnitude higher than in all the other semiconductors measured so far. The analysis of the dissipation curves clearly indicates that the nature of the H reorientation is quantistic.In metals two regimes of the H mobility are observed: hopping with deviations from a classical Arrhenius motion, and a much faster tunneling within few close sites. In the latter regime the H dynamics does not consist of jumps but of transitions between the quantized energy levels of the tunnel systems. The types of interactions assisting the H transitions and the geometry of the tunnel systems are an open problem: although the two-level tunnel system (TLS) has been widely used to explain neutron diffusion, specific heat, and acoustic spectroscopy results in interstitial solutions (NbOxHy), recently this model has appeared not to be valid in substitutional solutions (NbZrxHy, NbTixHy) where the tunnel systems have a higher symmetry. The four-level systems seem to be more appropriate, although the corresponding model has not been developed as much as the TLS yet.

scholarly journals METALLOTHIONEINS AS SENSORS AND CONTROLS EXCHANGE OF METALS IN THE CELLS

2014 ◽  
Vol 13 (3) ◽  
pp. 91-99 ◽  
Author(s):  
V. A. Kutyakov ◽  
A. V. Salmina
Keyword(s):  
Stress Factors ◽  
Special Role ◽  
Cellular Functions ◽  
Regulation Of Expression ◽  
Wide Range ◽  
Health And Disease ◽  
Pharmacology And Toxicology ◽  
Regulatory Functions ◽  
The Impact

The basic information on the classification, structure, induction and degradation, functions of the protein family – metallothionein (MT), including CNS in health and disease are presented in this review. It was found that four major isoforms of metallothionein perform different biological roles, are localized in dif- ferent tissues. Induction of MT is a universal reaction to the impact of a variety of stress factors. In recent years, understanding of the role of metallothioneins in metal homeostasis in the tissues in normal and pathological conditions have changed significantly. Notes polyfunctionality metallothioneins (transport of metal ions, maintaining redox reactions, tread, signal, modulated and regulatory functions) and their im- pact on basic cellular functions such as proliferation, differentiation, programmed cell death. Further- more, a special role is shown MT in the pathogenesis of cardiovascular, neurodegenerative and neoplastic disorders.Currently, these molecules are increasingly considered as potential targets for therapy of a wide range of diseases and the development of targeted approaches to the regulation of expression of MT – one of the promising areas of pharmacology and toxicology. Stressed the safety of metallothioneins as therapeutic agents.

scholarly journals Synthesis and Dissolution of Metal Oxides in Ionic Liquids and Deep Eutectic Solvents

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 78 ◽  
Author(s):  
Janine Richter ◽  
Michael Ruck
Keyword(s):  
Ionic Liquids ◽  
Low Temperature ◽  
Metal Oxide ◽  
Metal Oxides ◽  
High Temperatures ◽  
Deep Eutectic Solvents ◽  
Wide Range ◽  
Oxide Phases

Ionic liquids (ILs) and deep eutectic solvents (DESs) have proven to be suitable solvents and reactants for low-temperature reactions. To date, several attempts were made to apply this promising class of materials to metal oxide chemistry, which, conventionally, is performed at high temperatures. This review gives an overview about the scientific approaches of the synthesis as well as the dissolution of metal oxides in ILs and DESs. A wide range of metal oxides along with numerous ILs and DESs are covered by this research. With ILs and DESs being involved, many metal oxide phases as well as different particle morphologies were obtained by means of relatively simple reactions paths. By the development of acidic task-specific ILs and DESs, even difficultly soluble metal oxides were dissolved and, hence, made accessible for downstream chemistry. Especially the role of ILs in these reactions is in the focus of discussion.

scholarly journals Intraspecific Diversity in the Cold Stress Response of Transposable Elements in the Diatom Leptocylindrus aporus

Genes ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 9
Author(s):  
Aikaterini Pargana ◽  
Francesco Musacchia ◽  
Remo Sanges ◽  
Monia Teresa Russo ◽  
Maria Immacolata Ferrante ◽  
...  
Keyword(s):  
Stress Response ◽  
Low Temperature ◽  
Transposable Elements ◽  
Phenotypic Diversity ◽  
Intraspecific Variability ◽  
Intraspecific Diversity ◽  
Physiological Plasticity ◽  
Wide Range ◽  
Related Proteins

Transposable elements (TEs), activated as a response to unfavorable conditions, have been proposed to contribute to the generation of genetic and phenotypic diversity in diatoms. Here we explore the transcriptome of three warm water strains of the diatom Leptocylindrus aporus, and the possible involvement of TEs in their response to changing temperature conditions. At low temperature (13 °C) several stress response proteins were overexpressed, confirming low temperature to be unfavorable for L. aporus, while TE-related transcripts of the LTR retrotransposon superfamily were the most enriched transcripts. Their expression levels, as well as most of the stress-related proteins, were found to vary significantly among strains, and even within the same strains analysed at different times. The lack of overexpression after many months of culturing suggests a possible role of physiological plasticity in response to growth under controlled laboratory conditions. While further investigation on the possible central role of TEs in the diatom stress response is warranted, the strain-specific responses and possible role of in-culture evolution draw attention to the interplay between the high intraspecific variability and the physiological plasticity of diatoms, which can both contribute to the adaptation of a species to a wide range of conditions in the marine environment.

scholarly journals Bitkilerde Abiyotik Stres Toleransında Etkili Olan Moleküllere Örnek Olarak Eksojen Salisilik Asit Uygulamaları

2019 ◽  
Vol 7 (sp3) ◽  
pp. 5
Author(s):  
Ayşe Gül Nasırcılar ◽  
Kamile Ulukapı ◽  
Sevinç Şener
Keyword(s):  
Abiotic Stress ◽  
Low Temperature ◽  
Plant Growth ◽  
Plant Species ◽  
Cell Metabolism ◽  
Stress Conditions ◽  
Stress Factors ◽  
Coping With Stress ◽  
Abiotic Stress Factors ◽  
Mode Of Application

Plant growth and development, which is associated with endogenous and exogenous factors, is greatly affected by abiotic stress factors such as drought, salt, high and low temperature, radiation and heavy metals. Coping with stress in plants takes place by making changes in cell metabolism under adverse conditions and activating defence mechanisms. Salicylic acid (SA) is one of the molecules that activate these mechanisms in plants and it is an internal plant growth regulator which is especially effective in responding to pathogen attacks. SA, which is a phenolic compound and also known as a plant hormone, acts as a signalling molecule under stress conditions and regulates the response of the plant under stress conditions and ensures its survival. It is known that especially exogenous SA applications provide resistance by activating pathogenicity-related genes in plants. There are many studies showing that externally applied SA increases plant resistance against abiotic stress factors as well as biotic stress factors. Exogenous SA applications were researched in different plants such as tomato, pepper, corn, maize and bean and it was found to be effective in forming resistance for salt, high and low temperature, drought and heavy metal stresses. However, some studies have shown that exogenous SA applications have inhibitory properties in some vegetative and biochemical contents of some plant species. It is concluded that the effects of SA may vary depending on the application dose, plant species and the mode of application.

scholarly journals Fundamental limits on low-temperature quantum thermometry with finite resolution

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 161 ◽  
Author(s):  
Patrick P. Potts ◽  
Jonatan Bohr Brask ◽  
Nicolas Brunner
Keyword(s):  
Low Temperature ◽  
Tight Binding ◽  
Quantum Gases ◽  
Square Lattice ◽  
Fundamental Limits ◽  
Finite Resolution ◽  
Wide Range ◽  
Third Law Of Thermodynamics ◽  
Ideal Quantum

While the ability to measure low temperatures accurately in quantum systems is important in a wide range of experiments, the possibilities and the fundamental limits of quantum thermometry are not yet fully understood theoretically. Here we develop a general approach to low-temperature quantum thermometry, taking into account restrictions arising not only from the sample but also from the measurement process. {We derive a fundamental bound on the minimal uncertainty for any temperature measurement that has a finite resolution. A similar bound can be obtained from the third law of thermodynamics. Moreover, we identify a mechanism enabling sub-exponential scaling, even in the regime of finite resolution. We illustrate this effect in the case of thermometry on a fermionic tight-binding chain with access to only two lattice sites, where we find a quadratic divergence of the uncertainty}. We also give illustrative examples of ideal quantum gases and a square-lattice Ising model, highlighting the role of phase transitions.

Investigations on the adaptability of maize lines and hybrids to low temperature and cadmium

2005 ◽  
Vol 53 (2) ◽  
pp. 183-196 ◽  
Author(s):  
G. Szalai ◽  
M. Pál ◽  
E. Horváth ◽  
T. Janda ◽  
E. Páldi
Keyword(s):  
Enzyme Activity ◽  
Salicylic Acid ◽  
Low Temperature ◽  
Antioxidant Enzyme ◽  
Chilling Tolerance ◽  
Antioxidant Enzyme Activity ◽  
Stress Factors ◽  
Phytochelatin Synthase ◽  
Alternative Respiration ◽  
Tetrazolium Chloride

In the course of the Maize Consortium Project, investigations were made on the defence mechanisms employed by maize against various abiotic stress factors (low temperature, cadmium) and on the effects exerted by two compounds (S-methylmethionine, salicylic acid) capable of improving the stress resistance of plants to certain abiotic stresses. Salicylic acid (SA) was found to inhibit the uptake of cadmium (Cd), but caused damage to the roots, including a reduction in the activity of phytochelatin synthase (PCS), which meant that preliminary treatment with SA aggravated the damaging effect of Cd. It was also proved that as the result of 2-day treatment with Cd, there was a continuous rise in the Cd level in the plants, more Cd being accumulated in young leaves than in older ones. The PCS activity increased greatly after 24 hours, both in the leaves and in the roots, declining again after 2 days. The effect of SA was examined in both the hybrids and their parental lines, and the effect of this compound on the intensity of alternative respiration was also investigated. A comparison of chilling tolerance data and antioxidant enzyme activity indicated that these two parameters were not directly correlated to each other, i.e. antioxidant enzyme activity values could not be used to draw reliable conclusions on the chilling tolerance of maize lines and hybrids. With regard to the interaction between alternative respiration and salicylic acid, it was proved that exogenous hydrogen peroxide caused a similar increase in the ratio of alternative respiration to that observed after salicylic acid treatment. Abbreviations: SA, salicylic acid; Cd, cadmium; PCS, phytochelatin synthase; SMM, S-methylmethionine; PCs, phytochelatins; PAR, photosynthetically active radiation; TTC, triphenyl tetrazolium chloride; KCN, potassium cyanide; PSII, 2nd photochemical system; POD, guaiacol peroxidase; APX, ascorbate peroxidase; GR, glutathione reductase

Taxonomic distribution of thymoquinone and related compounds in selected plant species

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
J Táborský ◽  
M Kunt ◽  
P Kloucek ◽  
L Kokoska
Keyword(s):  
Plant Species ◽  
Taxonomic Distribution ◽  
Related Compounds
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