scholarly journals Chemical Reaction Networks Possess Intrinsic, Temperature-Dependent Functionality

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 117
Author(s):  
Stephan O. Adler ◽  
Edda Klipp
Keyword(s):  
Genetic Regulation ◽  
Calvin Cycle ◽  
Direct Consequence ◽  
Growth Conditions ◽  
Reaction Networks ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
Biochemical Processes ◽  
Functional Features ◽  
Regulatory Effects

Temperature influences the life of many organisms in various ways. A great number of organisms live under conditions where their ability to adapt to changes in temperature can be vital and largely determines their fitness. Understanding the mechanisms and principles underlying this ability to adapt can be of great advantage, for example, to improve growth conditions for crops and increase their yield. In times of imminent, increasing climate change, this becomes even more important in order to find strategies and help crops cope with these fundamental changes. There is intense research in the field of acclimation that comprises fluctuations of various environmental conditions, but most acclimation research focuses on regulatory effects and the observation of gene expression changes within the examined organism. As thermodynamic effects are a direct consequence of temperature changes, these should necessarily be considered in this field of research but are often neglected. Additionally, compensated effects might be missed even though they are equally important for the organism, since they do not cause observable changes, but rather counteract them. In this work, using a systems biology approach, we demonstrate that even simple network motifs can exhibit temperature-dependent functional features resulting from the interplay of network structure and the distribution of activation energies over the involved reactions. The demonstrated functional features are (i) the reversal of fluxes within a linear pathway, (ii) a thermo-selective branched pathway with different flux modes and (iii) the increased flux towards carbohydrates in a minimal Calvin cycle that was designed to demonstrate temperature compensation within reaction networks. Comparing a system’s response to either temperature changes or changes in enzyme activity we also dissect the influence of thermodynamic changes versus genetic regulation. By this, we expand the scope of thermodynamic modelling of biochemical processes by addressing further possibilities and effects, following established mathematical descriptions of biophysical properties.

scholarly journals Chemical Reaction Networks Possess Intrinsic, Temperature Dependent Functionality

2019 ◽  
Author(s):  
Stephan O. Adler ◽  
Edda Klipp
Keyword(s):  
Calvin Cycle ◽  
Direct Consequence ◽  
Growth Conditions ◽  
Reaction Networks ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
Biochemical Processes ◽  
Functional Features ◽  
Regulatory Effects ◽  
Simple Network

Temperature influences the life of many organisms in various ways. A great number of them live under conditions, where their ability to adapt to changes in temperature can be vital and largely determine their fitness. Understanding the mechanisms and principles underlying this ability to adapt can be of great advantage, for example, to improve growth conditions for crops and increase their yield. In times of imminent, increasing climate change, this becomes even more important, in order to find strategies and help crops cope with these fundamental changes. There is intense research in the field of acclimation, that comprises fluctuations of various environmental conditions, but most acclimation research focuses on regulatory effects and the observation of gene expression changes within the examined organism. As thermodynamic effects are a direct consequence of temperature changes, these should necessarily be considered in this field of research, but are often neglected. Also, compensated effects might be missed, even though they are equally important for the organism, since they do not cause observable changes, but rather counteract them. In this work, using a systems biology approach, we demonstrate that even simple network motifs can exhibit temperature dependent functional features, resulting from the interplay of network structure and the distribution of activation energies over the involved reactions. The demonstrated functional features are (i) the reversal of fluxes within a linear pathway, (ii) a thermo-selective branched pathway with different flux modes and (iii) the increased flux towards carbohydrates in a minimal calvin cycle that was designed to demonstrate temperature compensation within reaction networks. By this, we expand the scope of thermodynamic modelling of biochemical processes by addressing further possibilities and effects, following established mathematical descriptions of biophysical properties.

scholarly journals Naturally Occurring Ecdysteroids in Triticum aestivum L. and Evaluation of Fenarimol as a Potential Inhibitor of Their Biosynthesis in Plants

2021 ◽  
Vol 22 (6) ◽  
pp. 2855
Author(s):  
Anna Janeczko ◽  
Jana Oklestkova ◽  
Danuše Tarkowská ◽  
Barbara Drygaś
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Triticum Aestivum L ◽  
Growth Conditions ◽  
Animal Kingdom ◽  
Experimental Conditions ◽  
P450 Monooxygenase ◽  
Naturally Occurring ◽  
Regulatory Effects ◽  
Potential Use

Ecdysteroids (ECs) are steroid hormones originally found in the animal kingdom where they function as insect molting hormones. Interestingly, a relatively high number of these substances can also be formed in plant cells. Moreover, ECs have certain regulatory effects on plant physiology, but their role in plants still requires further study. One of the main aims of the present study was to verify a hypothesis that fenarimol, an inhibitor of the biosynthesis of ECs in the animal kingdom, also affects the content of endogenous ECs in plants using winter wheat Triticum aestivum L. as a model plant. The levels of endogenous ECs in winter wheat, including the estimation of their changes during a course of different temperature treatments, have been determined using a sensitive analytical method based on UHPLC-MS/MS. Under our experimental conditions, four substances of EC character were detected in the tissue of interest in amounts ranging from less than 1 to over 200 pg·g−1 FW: 20-hydroxyecdysone, polypodine B, turkesterone, and isovitexirone. Among them, turkesterone was observed to be the most abundant EC and accumulated mainly in the crowns and leaves of wheat. Importantly, the level of ECs was observed to be dependent on the age of the plants, as well as on growth conditions (especially temperature). Fenarimol, an inhibitor of a cytochrome P450 monooxygenase, was shown to significantly decrease the level of naturally occurring ECs in experimental plants, which may indicate its potential use in studies related to the biosynthesis and physiological function of these substances in plants.

Temperature-Dependent Photoluminescence Spectra of PbSe Quantum Dots for Temperature Markers

2012 ◽  
Vol 482-484 ◽  
pp. 2547-2550
Author(s):  
Peng Fei Gu ◽  
Ya Nan Wang ◽  
Jia Jia Cao ◽  
Yu Yan ◽  
Tie Qiang Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Temperature Sensitivity ◽  
Peak Position ◽  
Strong Temperature Dependence ◽  
Photoluminescence Spectra ◽  
Temperature Dependent ◽  
Temperature Variations ◽  
Temperature Changes ◽  
Optical Readout ◽  
Temperature Dependent Photoluminescence

We here report the temperature effect on photoluminescence(PL) spectra of PbSe quantum dots (QDs), which exhibit a strong temperature dependence on their spectra position and intensity. They potentially act as the temperature marker, sensing temperature variations and reporting temperature changes remotely through optical readout. In addition, the temperature sensitivity characterized by peak position of PbSe QDs was found to be 0.39nm/°C in a range of 10-100 °C.

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

scholarly journals Emission Characteristics of Fluorescent Labels with Respect to Temperature Changes and Subsequent Effects on DNA Microchip Studies

2005 ◽  
Vol 71 (10) ◽  
pp. 6453-6457 ◽  
Author(s):  
Wen-Tso Liu ◽  
Jer-Horng Wu ◽  
Emily Sze-Ying Li ◽  
Ezrein Shah Selamat
Keyword(s):  
Melting Curve ◽  
Melting Curve Analysis ◽  
Emission Characteristics ◽  
Fluorescent Labels ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
Formamide Concentration ◽  
Effects Of Temperature ◽  
Microarray Studies ◽  
Texas Red

ABSTRACT The effects of temperature, salt concentration, and formamide concentration on the emission characteristics of commonly used fluorescent labels were evaluated on DNA microchips. The emission intensities of different fluorophores without hybridization were observed to vary, each to a different extent, to mainly temperature changes. Rhodamine red, TAMRA (tetramethylrhodamine), and dyes from the carbocyanide group exhibited the largest variations, and Texas Red and Oregon Green exhibited the smallest variations. This temperature dependency was shown to affect results obtained during melting curve analysis in DNA microarray studies. To minimize the bias associated with the temperature-dependent emission of different fluorescent labels, a normalization step was proposed.

The Temperature-Dependent Ideal Shear Strength of Solid Single Crystals

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Tianbao Cheng ◽  
Daining Fang ◽  
Yazheng Yang
Keyword(s):  
Shear Strength ◽  
Theoretical Model ◽  
Melting Point ◽  
Single Crystals ◽  
Elevated Temperatures ◽  
Absolute Zero ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
First Time ◽  
The Ideal

Knowledge of the ideal shear strength of solid single crystals is of fundamental importance. However, it is very hard to determine this quantity at finite temperatures. In this work, a theoretical model for the temperature-dependent ideal shear strength of solid single crystals is established in the view of energy. To test the drawn model, the ideal shear properties of Al, Cu, and Ni single crystals are calculated and compared with that existing in the literature. The study shows that the ideal shear strength first remains approximately constant and then decreases almost linearly as temperature changes from absolute zero to melting point. As an example of application, the “brittleness parameter” of solids at elevated temperatures is quantitatively characterized for the first time.

Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition

2019 ◽  
Vol 52 (3) ◽  
pp. 637-642 ◽  
Author(s):  
Jiang-Dong Gao ◽  
Jian-Li Zhang ◽  
Xin Zhu ◽  
Xiao-Ming Wu ◽  
Chun-Lan Mo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Chemical Vapour ◽  
Direct Consequence ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Film Boundary ◽  
Detailed Surface ◽  
Boundary Facet ◽  
Metal Organic ◽  
Gan Film

The growth mechanism of V-defects in GaN films was investigated. It was observed that the crystal faces of both the sidewall of a V-defect and the sidewall of the GaN film boundary belong to the same plane family of \{ {{{10\bar 11}}} \}, which suggests that the formation of the V-defect is a direct consequence of spontaneous growth like that of the boundary facet. However, the growth rate of the V-defect sidewall is much faster than that of the boundary facet when the V-defect is filling up, implying that lateral growth of \{ {{{10\bar 11}}} \} planes is not the direct cause of the change in size of V-defects. Since V-defects originate from dislocations, an idea was proposed to correlate the growth of V-defects with the presence of dislocations. Specifically, the change in size of the V-defect is determined by the growth rate around dislocations and the growth rate around dislocations is determined by the growth conditions.

scholarly journals Unraveling the Molecular Basis of Temperature-Dependent Genetic Regulation in Penicillium marneffei

2013 ◽  
Vol 12 (9) ◽  
pp. 1214-1224 ◽  
Author(s):  
Ence Yang ◽  
Gang Wang ◽  
Patrick C. Y. Woo ◽  
Susanna K. P. Lau ◽  
Wang-Ngai Chow ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Current Knowledge ◽  
Genetic Regulation ◽  
Gene Clusters ◽  
Penicillium Marneffei ◽  
Integrated Analysis ◽  
Temperature Dependent ◽  
Mycelial Form ◽  
Content Type ◽  
Heat Response

ABSTRACTPenicillium marneffeiis an opportunistic fungal pathogen endemic in Southeast Asia, causing lethal systemic infections in immunocompromised patients.P. marneffeigrows in a mycelial form at the ambient temperature of 25°C and transitions to a yeast form at 37°C. The ability to alternate between the mycelial and yeast forms at different temperatures, namely, thermal dimorphism, has long been considered critical for the pathogenicity ofP. marneffei, yet the underlying genetic mechanisms remain elusive. Here we employed high-throughput sequencing to unravel global transcriptional profiles ofP. marneffeiPM1 grown at 25 and 37°C. Among ∼11,000 protein-coding genes, 1,447 were overexpressed and 1,414 were underexpressed at 37°C. Counterintuitively, heat-responsive genes, predicted inP. marneffeithrough sequence comparison, did not tend to be overexpressed at 37°C. These results suggest thatP. marneffeimay take a distinct strategy of genetic regulation at the elevated temperature; the current knowledge concerning fungal heat response, based on studies of model fungal organisms, may not be applicable toP. marneffei. Our results further showed that the tandem repeat sequences (TRSs) are overrepresented in coding regions ofP. marneffeigenes, and TRS-containing genes tend to be overexpressed at 37°C. Furthermore, genomic sequences and expression data were integrated to characterize gene clusters, multigene families, and species-specific genes ofP. marneffei. In sum, we present an integrated analysis and a comprehensive resource toward a better understanding of temperature-dependent genetic regulation inP. marneffei.

The Effect of Initial Growth Conditions on the Tilting of Lattice Planes in InP-ON-GaAs Heterostructures

1991 ◽  
Vol 238 ◽  
Author(s):  
Ferenc Riesz ◽  
K. Lischka ◽  
K. Rakennus ◽  
T. Hakkarainen ◽  
A. Pesek ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Initial Growth ◽  
Lattice Plane ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Gas Source ◽  
Gaas Substrates ◽  
Nucleation Model ◽  
Lattice Planes ◽  
Lower Temperature

ABSTRACTThe relative misorientation (tilt) between the epilayer and substrate (400) lattice planes of InP epilayers grown by gas-source molecular beam epitaxy on (100) GaAs substrates misoriented towards the (110) plane was studied by high resolution x-ray diffraction. For the growth temperature of 490–500°C, the direction of the relative tilt was nearly coincident with the direction of the substrate lattice plane tilting. In contrary, when a buffer layer was deposited at a lower temperature of 400–450°C prior to growth, an azimuthal rotation of about 45° was found between the directions of the relative tilt and the substrate lattice plane tilting. In order to explain the results, a temperature-dependent anisotropic nucleation model is proposed.

A Phase Model of Temperature-Dependent Mammalian Cold Receptors

2000 ◽  
Vol 12 (5) ◽  
pp. 1067-1093 ◽  
Author(s):  
Peter Roper ◽  
Paul C. Bressloff ◽  
André Longtin
Keyword(s):  
Temperature Sensitivity ◽  
Dynamic Range ◽  
Variable Number ◽  
Phase Model ◽  
Temperature Dependent ◽  
Firing Patterns ◽  
Temperature Changes ◽  
Cold Receptor ◽  
Cold Receptors ◽  
Deterministic Limit

We present a tractable stochastic phase model of the temperature sensitivity of a mammalian cold receptor. Using simple linear dependencies of the amplitude, frequency, and bias on temperature, the model reproduces the experimentally observed transitions between bursting, beating, and stochastically phase-locked firing patterns. We analyze the model in the deterministic limit and predict, using a Strutt map, the number of spikes per burst for a given temperature. The inclusion of noise produces a variable number of spikes per burst and also extends the dynamic range of the neuron, both of which are analyzed in terms of the Strutt map. Our analysis can be readily applied to other receptors that display various bursting patterns following temperature changes.

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