scholarly journals Modeling indicates degradation of mRNA and protein as a potential regulation mechanisms during cold acclimation

2021 ◽  
Author(s):  
Maria Krantz ◽  
Julia Legen ◽  
Yang Gao ◽  
Reimo Zoschke ◽  
Christian Schmitz-Linneweber ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Temperature Acclimation ◽  
Ode Model ◽  
Future Directions ◽  
Chloroplast Gene Expression ◽  
Temperature Changes ◽  
Regulation Mechanisms ◽  
Photosynthetic Complexes ◽  
Photosynthetic Reactions ◽  
Account Temperature

AbstractPlants are constantly exposed to temperature fluctuations, which have direct effects on all cellular reactions because temperature influences reaction likelihood and speed. Chloroplasts are crucial to temperature acclimation responses of plants, due to their photosynthetic reactions whose products play a central role in plant metabolism. Consequently, chloroplasts serve as sensors of temperature changes and are simultaneously major targets of temperature acclimation. The core subunits of the complexes involved in the light reactions of photosynthesis are encoded in the chloroplast. As a result, it is assumed that temperature acclimation in plants requires regulatory responses in chloroplast gene expression and protein turnover. We conducted western blot experiments to assess changes in the accumulation of two photosynthetic complexes (PSII, and Cytb6f complex) and the ATP synthase in tobacco plants over two days of acclimation to low temperature. Surprisingly, the concentration of proteins within the chloroplast varied negligibly compared to controls. To explain this observation, we used a simplified Ordinary Differential Equation (ODE) model of transcription, translation, mRNA degradation and protein degradation to explain how the protein concentration can be kept constant. This model takes into account temperature effects on these processes. Through simulations of the ODE model, we show that mRNA and protein degradation are possible targets for control during temperature acclimation. Our model provides a basis for future directions in research and the analysis of future results.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

scholarly journals Role of interleukins in the pathogenesis of pulmonary fibrosis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yi Xin She ◽  
Qing Yang Yu ◽  
Xiao Xiao Tang
Keyword(s):  
Pulmonary Fibrosis ◽  
Therapeutic Strategy ◽  
Future Directions ◽  
Regulation Mechanisms ◽  
Underlying Mechanisms ◽  
Multiple Cells ◽  
The Relationship

AbstractInterleukins, a group of cytokines participating in inflammation and immune response, are proved to be involved in the formation and development of pulmonary fibrosis. In this article, we reviewed the relationship between interleukins and pulmonary fibrosis from the clinical, animal, as well as cellular levels, and discussed the underlying mechanisms in vivo and in vitro. Despite the effects of interleukin-targeted treatment on experimental pulmonary fibrosis, clinical applications are lacking and unsatisfactory. We conclude that intervening in one type of interleukins with similar functions in IPF may not be enough to stop the development of fibrosis as it involves a complex network of regulation mechanisms. Intervening interleukins combined with other existing therapy or targeting interleukins affecting multiple cells/with different functions at the same time may be one of the future directions. Furthermore, the intervention time is critical as some interleukins play different roles at different stages. Further elucidation on these aspects would provide new perspectives on both the pathogenesis mechanism, as well as the therapeutic strategy and drug development.

Effects of High Temperature on Survival of the Giant Scallop

1958 ◽  
Vol 15 (6) ◽  
pp. 1189-1211 ◽  
Author(s):  
L. M. Dickie
Keyword(s):  
High Temperature ◽  
Temperature Acclimation ◽  
Direct Result ◽  
Acclimation Temperature ◽  
Lethal Temperature ◽  
Temperature Changes ◽  
Naturally Occurring ◽  
Special Circumstances ◽  
Summer Decline ◽  
Sudden Temperature Change

Upper lethal temperatures of scallops are raised 1 °C. by each increase of 5 °C. in acclimation temperature. Acclimation upwards is fairly rapid (average 1.7 °C. per day over part of the range). Loss of acclimation to high temperature is slow, and appears to take as long as 3 months. There is a winter-to-summer decline in lethal temperature. It appears that naturally occurring water temperatures over 23.5 °C. will be lethal to scallops and directly responsible for mortalities. Temperatures over 21 °C. may also be a direct cause of mortalities but only in special circumstances could mortalities occur as a direct result of temperatures below this. In the "sub-lethal" temperature range, sudden temperature changes upward or downward may so reduce scallop mobility as to make them easier prey to enemies. In this way sudden temperature change could be an indirect cause of increased mortality.

scholarly journals Chloroplast thioredoxin systems dynamically regulate photosynthesis in plants

2019 ◽  
Vol 476 (7) ◽  
pp. 1159-1172 ◽  
Author(s):  
Lauri Nikkanen ◽  
Eevi Rintamäki
Keyword(s):  
Photosynthetic Efficiency ◽  
Carbon Fixation ◽  
Current Knowledge ◽  
Light Energy ◽  
Crop Fields ◽  
Plant Chloroplast ◽  
Regulation Mechanisms ◽  
Controlled Environments ◽  
Photosynthetic Reactions ◽  
Light Energy Conversion

Abstract Photosynthesis is a highly regulated process in photoautotrophic cells. The main goal of the regulation is to keep the basic photosynthetic reactions, i.e. capturing light energy, conversion into chemical energy and production of carbohydrates, in balance. The rationale behind the evolution of strong regulation mechanisms is to keep photosynthesis functional under all conditions encountered by sessile plants during their lifetimes. The regulatory mechanisms may, however, also impair photosynthetic efficiency by overriding the photosynthetic reactions in controlled environments like crop fields or bioreactors, where light energy could be used for production of sugars instead of dissipation as heat and down-regulation of carbon fixation. The plant chloroplast has a high number of regulatory proteins called thioredoxins (TRX), which control the function of chloroplasts from biogenesis and assembly of chloroplast machinery to light and carbon fixation reactions as well as photoprotective mechanisms. Here, we review the current knowledge of regulation of photosynthesis by chloroplast TRXs and assess the prospect of improving plant photosynthetic efficiency by modification of chloroplast thioredoxin systems.

Tunable and Active Phononic Crystals and Metamaterials

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Yan-Feng Wang ◽  
Yi-Ze Wang ◽  
Bin Wu ◽  
Weiqiu Chen ◽  
Yue-Sheng Wang
Keyword(s):  
Phononic Crystals ◽  
Wave Functions ◽  
Ordered Structure ◽  
Bandgap Engineering ◽  
Future Directions ◽  
Unit Cells ◽  
Diverse Application ◽  
Recent Developments ◽  
Regulation Mechanisms ◽  
Mechanical Reconfiguration

Abstract Phononic crystals (PCs) and metamaterials (MMs) can exhibit abnormal properties, even far beyond those found in nature, through artificial design of the topology or ordered structure of unit cells. This emerging class of materials has diverse application potentials in many fields. Recently, the concept of tunable PCs or MMs has been proposed to manipulate a variety of wave functions on demand. In this review, we survey recent developments in tunable and active PCs and MMs, including bandgap and bandgap engineering, anomalous behaviors of wave propagation, as well as tunable manipulation of waves based on different regulation mechanisms: tunable mechanical reconfiguration and materials with multifield coupling. We conclude by outlining future directions in the emerging field.

Goal Dysregulation in Depression, Mania, and Schizophrenia

2019 ◽  
pp. 136-160
Author(s):  
Sheri L. Johnson ◽  
Amy H. Sanchez ◽  
Charles S. Carver
Keyword(s):  
Mood Disorders ◽  
Large Body ◽  
Basic Research ◽  
Clinical Implications ◽  
Future Directions ◽  
Goal Regulation ◽  
Regulation Mechanisms

This chapter addresses goal dysregulation in the mood disorders and schizophrenia. A large body of basic research has considered goal regulation mechanisms that support the pursuit of reward. This chapter outlines some components of goal regulation, their relevance for emotion, and some ways in which goal regulation can go awry. It begins by providing an overview of normative goal regulation processes and how these relate to emotion. Then, we discuss models and evidence concerning goal dysregulation across psychopathologies (depression, mania, and schizophrenia). The chapter concludes with a discussion of clinical implications of this work, unaddressed issues, and future directions.

Mechanisms of Acid-Base Adjustment in Dogfish (Scyliorhinus Stellaris) Subjected to Long-Term Temperature Acclimation

1980 ◽  
Vol 85 (1) ◽  
pp. 89-98
Author(s):  
N. HEISLER ◽  
P. NEUMANN ◽  
G. F. HOLETON
Keyword(s):  
Temperature Acclimation ◽  
Temperature Adaptation ◽  
Acclimation Temperature ◽  
Acid Base ◽  
Temperature Changes ◽  
Base Parameters ◽  
Intracellular Compartments ◽  
Relationship Of ◽  
The Relationship

Specimens of Larger Spotted Dogfish (Scyliorhinus stellaris) were acclimated to a range of temperatures for 22–28 days. The relationships of pH to acclimation temperature in the extracellular space and in three intracellular compartments were essentially the same as previously observed in 24 h acclimated dogfish (Heisler, Weitz & Weitz, 1976). In dogfish subjected to elevated inspired PCO2 during acclimation to low temperature, there was an inversion in the relationship of acclimation temperature to plasma PCO2, and in that to plasma bicarbonate, whereas the relationships to pH values were unchanged. It is concluded that the temperature adaptation of the acid-base parameters is complete after 24 h of temperature acclimation. At least the following mechanisms are involved in the adjustment of pH with changes of temperature: changes of PCO2, changes of buffer pK values, and transmembrane transfer of bicarbonate. Apparently only one of them, the transmembrane transfer of bicarbonate, can be modulated in a sufficient range and is responsible for the final pH adjustment.

scholarly journals Temperature Acclimation of the Picoalga Ostreococcus tauri Triggers Early Fatty-Acid Variations and Involves a Plastidial ω3-Desaturase

2021 ◽  
Vol 12 ◽  
Author(s):  
Charlotte Degraeve-Guilbault ◽  
Nattiwong Pankasem ◽  
Maurean Gueirrero ◽  
Cécile Lemoigne ◽  
Frédéric Domergue ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Molecular Mechanisms ◽  
Temperature Acclimation ◽  
Omega 3 ◽  
Temperature Changes ◽  
Ostreococcus Tauri ◽  
Physiological Relevance ◽  
Omega 6 ◽  
3 Omega ◽  
Response To Temperature

Alteration of fatty-acid unsaturation is a universal response to temperature changes. Marine microalgae display the largest diversity of polyunsaturated fatty-acid (PUFA) whose content notably varies according to temperature. The physiological relevance and the molecular mechanisms underlying these changes are however, still poorly understood. The ancestral green picoalga Ostreococcus tauri displays original lipidic features that combines PUFAs from two distinctive microalgal lineages (Chlorophyceae, Chromista kingdom). In this study, optimized conditions were implemented to unveil early fatty-acid and desaturase transcriptional variations upon chilling and warming. We further functionally characterized the O. tauri ω3-desaturase which is closely related to ω3-desaturases from Chromista species. Our results show that the overall omega-3 to omega-6 ratio is swiftly and reversibly regulated by temperature variations. The proportion of the peculiar 18:5 fatty-acid and temperature are highly and inversely correlated pinpointing the importance of 18:5 temperature-dependent variations across kingdoms. Chilling rapidly and sustainably up-regulated most desaturase genes. Desaturases involved in the regulation of the C18-PUFA pool as well as the Δ5-desaturase appear to be major transcriptional targets. The only ω3-desaturase candidate, related to ω3-desaturases from Chromista species, is localized at chloroplasts in Nicotiana benthamiana and efficiently performs ω3-desaturation of C18-PUFAs in Synechocystis sp. PCC6803. Overexpression in the native host further unveils a broad impact on plastidial and non-plastidial glycerolipids illustrated by the alteration of omega-3/omega-6 ratio in C16-PUFA and VLC-PUFA pools. Global glycerolipid features of the overexpressor recall those of chilling acclimated cells.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

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