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Heat acclimation

Douglas M Jones, Bart Roelands, Stephen P Bailey, Michael J Buono, Romain Meeusen
PURPOSE: It is well-documented that severe cold stress impairs exercise performance. Repeated immersion in cold water induces an insulative type of cold acclimation, wherein enhanced vasoconstriction leads to greater body heat retention, which may attenuate cold-induced exercise impairments. The purpose of this study, therefore, was to investigate changes in exercise performance during a 7-day insulative type of cold acclimation. METHODS: Twelve healthy participants consisting of eight males and four females (mean ± SD age: 25...
March 19, 2018: European Journal of Applied Physiology
Barbara Demmig-Adams, Jared J Stewart, Christopher R Baker, William W Adams
We review the role of a family of transcription factors and their regulons in maintaining high photosynthetic performance across a range of challenging environments with a focus on extreme temperatures and water availability. Specifically, these transcription factors include CBFs (C-repeat binding factors) and DREBs (dehydration-responsive element-binding), with CBF/DREB1 primarily orchestrating cold adaptation and other DREBs serving in heat, drought, and salinity adaptation. The central role of these modulators in plant performance under challenging environments is based on (i) interweaving of these regulators with other key signaling networks (plant hormones and redox signals) as well as (ii) their function in integrating responses across the whole plant, from light-harvesting and sugar-production in the leaf to foliar sugar export and water import and on to the plant's sugar-consuming sinks (growth, storage, and reproduction)...
March 15, 2018: International Journal of Molecular Sciences
Qing-Long Wang, Juan-Hua Chen, Ning-Yu He, Fang-Qing Guo
Increases in ambient temperatures have been a severe threat to crop production in many countries around the world under climate change. Chloroplasts serve as metabolic centers and play a key role in physiological adaptive processes to heat stress. In addition to expressing heat shock proteins that protect proteins from heat-induced damage, metabolic reprogramming occurs during adaptive physiological processes in chloroplasts. Heat stress leads to inhibition of plant photosynthetic activity by damaging key components functioning in a variety of metabolic processes, with concomitant reductions in biomass production and crop yield...
March 14, 2018: International Journal of Molecular Sciences
Almudena Trapero-Mozos, Laurence J M Ducreux, Craita E Bita, Wayne Morris, Cosima Wiese, Jenny A Morris, Christy Paterson, Peter E Hedley, Robert D Hancock, Mark Taylor
A powerful acquired thermotolerance response in potato was demonstrated and characterised in detail, showing the time course required for tolerance, the reversibility of the process and requirement for light. Potato is particularly vulnerable to increased temperature, considered to be the most important uncontrollable factor affecting growth and yield of this globally significant crop. Here, we describe an acquired thermotolerance response in potato, whereby treatment at a mildly elevated temperature primes the plant for more severe heat stress...
March 8, 2018: Planta
Vicente Martinez, Manuel Nieves-Cordones, Maria Lopez-Delacalle, Reyes Rodenas, Teresa C Mestre, Francisco Garcia-Sanchez, Francisco Rubio, Pedro A Nortes, Ron Mittler, Rosa M Rivero
Abiotic stresses such as drought, heat or salinity are major causes of yield loss worldwide. Recent studies have revealed that the acclimation of plants to a combination of different environmental stresses is unique and therefore cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. The efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Here, we report on the role of melatonin in the protection of the photosynthetic apparatus through the increase in ROS detoxification in tomato plants grown under the combination of salinity and heat, two of the most common abiotic stresses known to act jointly...
February 28, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Gaurav Zinta, Hamada AbdElgawad, Darin Peshev, James T Weedon, Wim Van den Ende, Ivan Nijs, Ivan A Janssens, Gerrit T S Beemster, Asard Han
As a consequence of global change processes, plants will be increasingly challenged by extreme climatic events, against a background of elevated atmospheric CO2. We analysed responses of Arabidopsis thaliana to a combination of heat wave and water deficit at ambient and elevated CO2, and provided mechanistic insight on changes in primary metabolism. Climate extreme-induced metabolic changes are dynamic and molecule class-specific. Concentrations of soluble sugars and amino acids increased transiently after short (4 d) exposure to heat and drought, and readjusted to control levels under prolonged (8 d) stress...
February 15, 2018: Journal of Experimental Botany
Stephanie Buijs, Francesca Booth, Gemma Richards, Laura McGaughey, Christine J Nicol, Joanne Edgar, John F Tarlton
Automated monitoring of behaviour can offer a wealth of information in circumstances where observing behaviour is difficult or time consuming. However, this often requires attaching monitoring devices to the animal which can alter behaviour, potentially invalidating any data collected. Birds often show increased preening and energy expenditure when wearing devices and, especially in laying hens, there is a risk that individuals wearing devices will attract aggression from conspecifics. We studied the behavioural and physiological response of 20 laying hens to backpacks containing monitoring devices fastened with elastic loops around the wing base...
February 2018: Applied Animal Behaviour Science
Catarina Vinagre, Vanessa Mendonça, Rui Cereja, Francisca Abreu-Afonso, Marta Dias, Damián Mizrahi, Augusto A V Flores
Mortality of fish has been reported in tide pools during warm days. That means that tide pools are potential ecological traps for coastal organisms, which happen when environmental changes cause maladaptive habitat selection. Heat-waves are predicted to increase in intensity, duration and frequency, making it relevant to investigate the role of tide pools as traps for coastal organisms. However, heat waves can also lead to acclimatization. If organisms undergo acclimatization prior to being trapped in tide pools, their survival chances may increase...
2018: PloS One
Joseph T Costello, Rebecca A Rendell, Matthew Furber, Heather C Massey, Michael J Tipton, John S Young, Jo Corbett
This study examined the acute and chronic effects of euhydrated and hypohydrated heat exposure, on biomarkers of stress and inflammation. Eight trained males [mean (SD) age: 21 (3) y; mass: 77.30 (4.88) kg; V̇O2max: 56.9 (7.2) mL kg-1 min-1] undertook two heat acclimation programmes (balanced cross-over design), once drinking to maintain euhydration and once with restricted fluid-intake (permissive dehydration). Days 1, 6, and 11 were 60 min euhydrated exercise-heat stress tests (40 °C; 50% RH, 35% peak power output), days 2-5 and 7-10 were 90 min, isothermal-strain (target rectal temperature: 38...
February 2, 2018: Cytokine
Geun-Don Kim, Sang-Dong Yoo, Young-Hee Cho
To overcome high temperature stress, plants have developed transcriptional cascades which express a large amount of chaperone proteins called heat shock proteins (HSPs). In our recent publication, we reported that STABILIZED1, as an U5-snRNP-interacting protein, is involved in the splicing of heat shock factor (HSF) and HSP transcripts during high temperature stress. This indicates that not only transcriptional regulation, but also post-transcriptional regulation by STA1, is essential for the full activation of HSF-HSP cascades and for thermotolerance...
January 30, 2018: Plant Signaling & Behavior
Ciaran A Shaughnessy, Stephen D McCormick
The aims of this study were to assess whether thermal tolerance of brook trout (Salvelinus fontinalis) is affected during seawater (SW) acclimation and to investigate the role of cortisol in osmoregulation and thermal tolerance during SW acclimation. Freshwater (FW)-acclimated brook trout at 18 °C (Tacc) were exposed to SW for 16 d, whilst maintaining a FW control. Fish were examined for critical thermal maximum (CTmax) 0 (before), 2, 5, and 16 d after SW exposure, and sampled at Tacc and CTmax for analysis of plasma cortisol, glucose, and Cl-, gill Na+/K+-ATPase (NKA) activity and heat shock protein 70 (HSP70) abundance, and white muscle water content...
January 29, 2018: Journal of Experimental Biology
Li Zhang, Meng-Yao Wang, Xiao-Peng Li, Xiao-Tong Wang, Cheng-Lin Jia, Xing-Zhuo Yang, Run-Qiu Feng, Ming-Long Yuan
Color polymorphism is an ecologically important trait, which is related to local adaptation and ecological speciation. The pea aphid Acyrthosiphon pisum shows color polymorphism: the red and green color morphs where differences in ecological adaptation have been observed. Here, we measured genome-wide gene expression profiles of two color morphs in natural populations of A. pisum to explore the genetic basis of differentiated ecological adaptation. The results showed that only 32 genes were significantly differentially expressed between the two morphs, of which 18 had functional annotations...
January 25, 2018: Gene
Silva Suvi, Martin Mooses, Saima Timpmann, Luule Medijainen, Daria Narõškina, Eve Unt, Vahur Ööpik
The purpose of this study was to assess the impact of sodium citrate (CIT) ingestion (600 mg·kg<sup>‒1</sup>) during recovery from dehydrating cycling exercise (DE) on subsequent 40-km cycling performance in a warm environment (32 °C). Twenty male non-heat-acclimated endurance athletes exercised in the heat until 4% body mass (BM) loss occurred. After 16 h recovery with consumption of water ad libitum and prescribed diet (evening meal 20 kcal·kg<sup>‒1</sup>, breakfast 12 kcal·kg<sup>‒1</sup>) supplemented in a double-blind, randomized, crossover manner with CIT or placebo (PLC), they performed 40-km time-trial (TT) on a cycle ergometer in a warm environment...
January 11, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Kentaro Matsuzaki, Naotoshi Sugimoto, Masanori Katakura, Eri Sumiyoshi, Toshiko Hara, Michio Hashimoto, Osamu Shido
Saliva-a water-based fluid containing electrolytes, immunoglobulins, and enzymes-has many functions, including the protection and hydration of mucosal structures within the oral cavity and the initiation of digestion. Aquaporins (AQPs) are proteins that act as water channels through membranes. We have previously reported upregulation of the expression levels of AQP 1 and 5 in the submandibular glands (SMGs) in heat-acclimated rats. In this study, we investigated pilocarpine-induced saliva secretion and AQP expression in rats after voluntary exercise...
January 2018: FEBS Open Bio
Brett R Ely, Laurie A Blanchard, Jared R Steele, Michael A Francisco, Samuel N Cheuvront, Christopher T Minson
Heat acclimation is the best strategy to improve performance in a hot environment. Many athletes seeking the benefits of heat acclimation lack access to a hot environment for exercise, and thus rely on over-dressing to simulate environmental heat stress. It is currently unknown whether this approach produces the requisite thermoregulatory strain necessary for heat acclimation in trained men and women. PURPOSE: To compare physiological and cellular responses to exercise in a hot environment (HOT; 40°C, 30%rh) with minimal clothing (clo= 0...
January 9, 2018: Medicine and Science in Sports and Exercise
Lingling Zhu, Keith J Bloomfield, Charles H Hocart, John J G Egerton, Odhran S O'Sullivan, Aurore Penillard, Lasantha K Weerasinghe, Owen K Atkin
In many biomes, plants are subject to heat-waves, potentially causing irreversible damage to the photosynthetic apparatus. Field surveys have documented global, temperature-dependent patterns in photosynthetic heat tolerance (PHT ); however, it remains unclear if these patterns reflect acclimation in PHT or inherent differences among species adapted to contrasting habitats. To address these unknowns, we quantified seasonal variations in Tcrit (high temperature where minimal chlorophyll-a fluorescence rises rapidly, reflecting disruption to photosystem II) in 62 species native to six sites from five thermally-contrasting biomes across Australia...
January 5, 2018: Plant, Cell & Environment
Maria Cuenca Cambronero, Bettina Zeis, Luisa Orsini
Anthropogenic global warming has become a major geological and environmental force driving drastic changes in natural ecosystems. Due to the high thermal conductivity of water and the effects of temperature on metabolic processes, freshwater ecosystems are among the most impacted by these changes. The ability to tolerate changes in temperature may determine species long-term survival and fitness. Therefore, it is critical to identify coping mechanisms to thermal and hyper-thermal stress in aquatic organisms...
January 2018: Evolutionary Applications
Michael J Buono, Mark Kolding, Eric Leslie, Daniel Moreno, Sarah Norwood, Andrew Ordille, Rebecca Weller
The purpose of this study was to determine the time course for the previously reported reduction in sweat sodium ion concentration during heat acclimation. Four healthy volunteers completed 7 consecutive days of heat acclimation which included 2h of treadmill walking in a 40°C and 40% relative humidity environment. A modified constant hyperthermia protocol was used as workloads were increased each day to maintain a constant core temperature over the 7 days of heat acclimation. Forearm sweat was collected 3 times during each 2h exercise bout on days 1, 3, 5, and 7 of heat acclimation...
January 2018: Journal of Thermal Biology
Meng Li, Xiao-Juan Li, Jian-Hua Lü, Ming-Fei Huo
Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) is an important economic insect of various stored products worldwide. With the restricted use of methyl bromide and the increasing negative effects of repeated use of phosphine fumigation, heat treatment becomes the main approach to control stored-product insects. We investigated effect of the acclimation to sublethal high temperature of 36°C and 42°C for different times on heat tolerance of L. serricorne adults, pupae, larvae, and eggs to lethal high temperature of 50°C in laboratory...
January 2018: Journal of Thermal Biology
Md Emon Hossain, Kentaro Matsuzaki, Masanori Katakura, Naotoshi Sugimoto, Abdullah Al Mamun, Rafiad Islam, Michio Hashimoto, Osamu Shido
Heat acclimation in rats is associated with enhanced neurogenesis in thermoregulatory centers of the hypothalamus. To elucidate the mechanisms for heat acclimation, we investigated the effects of direct mild heat exposure on the proliferation and differentiation of neural stem/progenitor cells (NSCs/NPCs). The NSCs/NPCs isolated from forebrain cortices of 14.5-day-old rat fetuses were propagated as neurospheres at either 37.0°C (control) or 38.5°C (mild heat exposure) for four days, and the effects on proliferation were investigated by MTS cell viability assay, measurement of neurosphere diameter, and counting the total number of cells...
2017: PloS One
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