Biosynthetic Cause of in Vivo Acquired Thermotolerance of Photosynthetic Light Reactions and Metabolic Responses of Chloroplasts to Heat Stress

A controlled crossover experimental design was used to determine the effect of altered water sprinkling duration on heifers subjected to heat stress conditions. Heifers were subjected to 3 days of thermoneutral conditions followed by 3 days of hot conditions accompanied by water sprinkling between 1300 and 1500 h (HOT1–3). Then on the following 2 days (HOT4–5), environmental conditions remained similar, but 3 heifers were sprinkled between 1200 and 1600 h (WET) and 3 were not sprinkled (NONWET). This was followed by a 1-day period (HOT6) in which environmental conditions and sprinkling regimen were similar to HOT1–3. Rectal temperature (RT) was collected hourly, and respiration rate (RR) was monitored every 2 h on HOT Days 2, 4, 5, and 6. Dry matter intake and rate of eating were also determined. Sprinkling reduced RR and RT (P < 0.01) of all heifers during HOT1–3. During HOT4–5, WET heifers had lower (P < 0.05) RT than NONWET from 1300 to 700 h and lower RR from 1400 to 2000 h. Dry matter intake of NONWET heifers was reduced by 30.6% (P < 0.05) during HOT4–5 and by 51.2% on HOT6. On HOT4–5 the dry matter intakes of WET heifers were similar to intakes under thermoneutral conditions. During HOT6, RT was again reduced following sprinkling in all heifers. Comparison of RT and RR of NONWET and WET heifers on HOT1–3 v. HOT6 revealed that under similar environmental conditions, NONWET heifers had increased RT, partially due to carry-over from HOT4–5. However, NONWET heifers had 40% lower feed intake but tended to have lower RR on HOT6 v. HOT1–3. Only RR of WET heifers was greater on HOT6, possibly a result of switching from a 4-h back to a 2-h sprinkling period, while maintaining a 62% greater intake (5.80 v. 3.58 kg/day) than NONWET heifers during this time. Results suggest that inconsistent cooling regimens may increase the susceptibility of cattle to heat stress and elicit different physiological and metabolic responses.

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Prior heat stress enhances survival of renal epithelial cells after ATP depletion

AJP Renal Physiology ◽

10.1152/ajprenal.1996.270.6.f1057 ◽

1996 ◽

Vol 270 (6) ◽

pp. F1057-F1065 ◽

Cited By ~ 13

Author(s):

Y. H. Wang ◽

S. C. Borkan

Keyword(s):

Heat Stress ◽

Epithelial Cells ◽

Recovery Period ◽

Atp Depletion ◽

Protective Effects ◽

Atp Content ◽

Renal Epithelial Cells ◽

Opossum Kidney ◽

Ok Cells

The 72-kDa heat stress protein (HSP-72) is an inducible cytoprotectant protein. Although transient renal ischemia in vivo induces HSP-72, it is not known whether prior heat stress protects renal epithelial cells from injury mediated by ATP depletion. To evaluate this hypothesis, opossum kidney (OK) cells were exposed to sodium cyanide and 2-deoxy-D-glucose in the absence of medium glucose, a maneuver that reduced cell ATP content to < 10% of the control value within 10 min and decreased cell survival. One day after 2 h of ATP depletion, OK cells previously exposed to heat stress (to induce accumulation of HSP-72) exhibited marked improvement in survival (a > 4-fold increase in total DNA), less uptake of vital dye, and less release of lactate dehydrogenase (LDH) than cells subjected to ATP depletion alone (23.0 +/- 1.6 vs. 34.1 +/- 1.2% of total LDH, respectively). Enhanced clonogenicity post-heat stress was completely prevented by cycloheximide and positively correlated with the steady-state content of HSP-72. In the recovery period after ATP depletion, cell ATP content, maximum mitochondrial ATP production rate, and total LDH activity were all significantly higher in cells with abundant HSP-72. Although the protective effects associated with heat stress are likely to be multifactoral, preserved cell metabolism and higher ATP content could enhance cellular repair processes after ATP depletion.

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Metabolic responses of rice cultivars with different tolerance to combined drought and heat stress under field conditions

GigaScience ◽

10.1093/gigascience/giz050 ◽

2019 ◽

Vol 8 (5) ◽

Cited By ~ 11

Author(s):

Lovely Mae F Lawas ◽

Xia Li ◽

Alexander Erban ◽

Joachim Kopka ◽

S V Krishna Jagadish ◽

...

Keyword(s):

Heat Stress ◽

Field Conditions ◽

Metabolic Responses ◽

Rice Cultivars ◽

Drought And Heat Stress

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AtPPRT1, an E3 Ubiquitin Ligase, Enhances the Thermotolerance in Arabidopsis

Plants ◽

10.3390/plants9091074 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1074

Author(s):

Yu Liu ◽

Shuya Xiao ◽

Haoran Sun ◽

Linsen Pei ◽

Yingying Liu ◽

...

Keyword(s):

Heat Stress ◽

Ubiquitin Ligase ◽

E3 Ubiquitin Ligase ◽

Degradation Pathway ◽

Vital Role ◽

Loss Of Function ◽

Positive Role ◽

Heat Stress Response ◽

Acquired Thermotolerance ◽

Ubiquitin E3 Ligase

E3 ubiquitin ligase plays a vital role in the ubiquitin-mediated heat-related protein degradation pathway. Herein, we report that the expression of AtPPRT1, a C3HC4 zinc-finger ubiquitin E3 ligase gene, was induced by heat stress, and the β-glucuronidase (GUS) gene driven by the AtPPRT1 promoter has shown increased activity after basal and acquired thermotolerance. To further explore the function of AtPPRT1 in heat stress response (HSR), we used the atpprt1 mutant and AtPPRT1-overexpressing lines (OE2 and OE10) to expose in heat shock. In this study, the atpprt1 mutant had a lower germination and survival rate than those of Col-0 when suffered from the heat stress, whereas OEs enhanced basal and acquired thermotolerance in Arabidopsis seedlings. When compared to Col-0 and OEs, loss-of-function in AtPPRT1 resulted in lower chlorophyll retention and higher content of reactive oxygen species (ROS) after heat treatment. Moreover, the transcript levels of AtPPRT1 and several heat-related genes (AtZAT12, AtHSP21 and AtHSFA7a) were upregulated to greater extents in OEs and lower extents in atpprt1 compared to Col-0 after heat treated. Hence, we suggest that AtPPRT1 may act as a positive role in regulating the high temperature by mediating the degradation of unknown target proteins.

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Ecometabolomics for a Better Understanding of Plant Responses and Acclimation to Abiotic Factors Linked to Global Change

Metabolites ◽

10.3390/metabo10060239 ◽

2020 ◽

Vol 10 (6) ◽

pp. 239 ◽

Cited By ~ 3

Author(s):

Jordi Sardans ◽

Albert Gargallo-Garriga ◽

Otmar Urban ◽

Karel Klem ◽

Tom W.N. Walker ◽

...

Keyword(s):

Amino Acids ◽

Heat Stress ◽

Global Change ◽

Secondary Metabolites ◽

De Novo ◽

Abiotic Factors ◽

Soluble Sugars ◽

Metabolic Responses ◽

Plant Responses ◽

Co2 Concentrations

The number of ecometabolomic studies, which use metabolomic analyses to disentangle organisms’ metabolic responses and acclimation to a changing environment, has grown exponentially in recent years. Here, we review the results and conclusions of ecometabolomic studies on the impacts of four main drivers of global change (increasing frequencies of drought episodes, heat stress, increasing atmospheric carbon dioxide (CO2) concentrations and increasing nitrogen (N) loads) on plant metabolism. Ecometabolomic studies of drought effects confirmed findings of previous target studies, in which most changes in metabolism are characterized by increased concentrations of soluble sugars and carbohydrate derivatives and frequently also by elevated concentrations of free amino acids. Secondary metabolites, especially flavonoids and terpenes, also commonly exhibited increased concentrations when drought intensified. Under heat and increasing N loads, soluble amino acids derived from glutamate and glutamine were the most responsive metabolites. Foliar metabolic responses to elevated atmospheric CO2 concentrations were dominated by greater production of monosaccharides and associated synthesis of secondary metabolites, such as terpenes, rather than secondary metabolites synthesized along longer sugar pathways involving N-rich precursor molecules, such as those formed from cyclic amino acids and along the shikimate pathway. We suggest that breeding for crop genotypes tolerant to drought and heat stress should be based on their capacity to increase the concentrations of C-rich compounds more than the concentrations of smaller N-rich molecules, such as amino acids. This could facilitate rapid and efficient stress response by reducing protein catabolism without compromising enzymatic capacity or increasing the requirement for re-transcription and de novo biosynthesis of proteins.

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Short-term exercise improves myocardial tolerance to in vivo ischemia-reperfusion in the rat

Journal of Applied Physiology ◽

10.1152/jappl.2001.91.5.2205 ◽

2001 ◽

Vol 91 (5) ◽

pp. 2205-2212 ◽

Cited By ~ 120

Author(s):

Haydar A. Demirel ◽

Scott K. Powers ◽

Murat A. Zergeroglu ◽

R. Andrew Shanely ◽

Karyn Hamilton ◽

...

Keyword(s):

Heat Stress ◽

Maximum Rate ◽

Treadmill Exercise ◽

Ischemia Reperfusion ◽

Left Ventricular ◽

Antioxidant Defenses ◽

Whole Body ◽

Sprague Dawley ◽

Short Term

These experiments examined the independent effects of short-term exercise and heat stress on myocardial responses during in vivo ischemia-reperfusion (I/R). Female Sprague-Dawley rats (4 mo old) were randomly assigned to one of four experimental groups: 1) control, 2) 3 consecutive days of treadmill exercise [60 min/day at 60–70% maximal O2 uptake (V˙o 2 max)], 3) 5 consecutive days of treadmill exercise (60 min/day at 60–70%V˙o 2 max), and 4) whole body heat stress (15 min at 42°C). Twenty-four hours after heat stress or exercise, animals were anesthetized and mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was maintained for 30-min followed by a 30-min period of reperfusion. Compared with control, both heat-stressed animals and exercised animals (3 and 5 days) maintained higher ( P < 0.05) left ventricular developed pressure (LVDP), maximum rate of left venticular pressure development (+dP/d t), and maximum rate of left ventricular pressure decline (−dP/d t) at all measurement periods during both ischemia and reperfusion. No differences existed between heat-stressed and exercise groups in LVDP, +dP/d t, and −dP/d t at any time during ischemia or reperfusion. Both heat stress and exercise resulted in an increase ( P < 0.05) in the relative levels of left ventricular heat shock protein 72 (HSP72). Furthermore, exercise (3 and 5 days) increased ( P < 0.05) myocardial glutathione levels and manganese superoxide dismutase activity. These data indicate that 3–5 consecutive days of exercise improves myocardial contractile performance during in vivo I/R and that this exercise-induced myocardial protection is associated with an increase in both myocardial HSP72 and cardiac antioxidant defenses.

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Arteriolar vasoconstriction in rat cremaster muscle induced by local heat stress

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1982.242.6.h996 ◽

1982 ◽

Vol 242 (6) ◽

pp. H996-H999

Author(s):

R. D. Hogan ◽

T. D. Franklin ◽

K. S. Avery ◽

K. M. Burke

Keyword(s):

Heat Stress ◽

Bath Temperature ◽

Local Heat ◽

Blocking Agent ◽

Muscle Temperature ◽

Cremaster Muscle ◽

Cell Velocity ◽

Red Blood Cell Velocity ◽

Arteriolar Tone

The effect of moderate local heat stress on arteriolar tone in the cremaster muscle of anesthetized rats was investigated by direct microscopic observation. Muscle temperature was raised from the in vivo temperature of 34.5 to 38 degrees C, over a 5-min period, by elevating bath temperature. Muscle temperature, arteriolar lumen diameter, and arteriolar red blood cell velocity were continuously recorded. A number of the smallest arterioles studied (approximately 30 micrometers lumen diam) underwent a rapid and significant vasoconstriction near 36 degrees C. Denervation of the muscle eliminated the constrictor response. Addition of an alpha-blocking agent (dibenzyline to the denervated muscle unmasked the constriction, but the percent of arterioles demonstrating thermal reactivity remained decreased. We conclude that in some skeletal muscle beds a local thermoregulatory mechanism may exist whereby blood is shunted away from the tissue during heat stress at rest.

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Gene expression of the heat stress response in bovine peripheral white blood cells and milk somatic cells in vivo

Scientific Reports ◽

10.1038/s41598-020-75438-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

J. B. Garner ◽

A. J. Chamberlain ◽

C. Vander Jagt ◽

T. T. T. Nguyen ◽

B. A. Mason ◽

...

Keyword(s):

Gene Expression ◽

Heat Stress ◽

Blood Cells ◽

White Blood Cells ◽

Somatic Cells ◽

Holstein Friesian ◽

Milk Somatic Cells ◽

Peripheral White Blood Cells ◽

Friesian Cows

Abstract Heat stress in dairy cattle leads to reduction in feed intake and milk production as well as the induction of many physiological stress responses. The genes implicated in the response to heat stress in vivo are not well characterised. With the aim of identifying such genes, an experiment was conducted to perform differential gene expression in peripheral white blood cells and milk somatic cells in vivo in 6 Holstein Friesian cows in thermoneutral conditions and in 6 Holstein Friesian cows exposed to a short-term moderate heat challenge. RNA sequences from peripheral white blood cells and milk somatic cells were used to quantify full transcriptome gene expression. Genes commonly differentially expressed (DE) in both the peripheral white blood cells and in milk somatic cells were associated with the cellular stress response, apoptosis, oxidative stress and glucose metabolism. Genes DE in peripheral white blood cells of cows exposed to the heat challenge compared to the thermoneutral control were related to inflammation, lipid metabolism, carbohydrate metabolism and the cardiovascular system. Genes DE in milk somatic cells compared to the thermoneutral control were involved in the response to stress, thermoregulation and vasodilation. These findings provide new insights into the cellular adaptations induced during the response to short term moderate heat stress in dairy cattle and identify potential candidate genes (BDKRB1 and SNORA19) for future research.

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Insights into Regulation and Function of the Major Stress-Induced hsp70 Molecular Chaperone In Vivo: Analysis of Mice with Targeted Gene Disruption of the hsp70.1 orhsp70.3 Gene

Molecular and Cellular Biology ◽

10.1128/mcb.21.24.8575-8591.2001 ◽

2001 ◽

Vol 21 (24) ◽

pp. 8575-8591 ◽

Cited By ~ 99

Author(s):

Lei Huang ◽

Nahid F. Mivechi ◽

Demetrius Moskophidis

Keyword(s):

Heat Stress ◽

Gene Family ◽

Synergistic Effects ◽

Single Gene ◽

Physiological Role ◽

Evolutionary Significance ◽

Homologous Gene ◽

Transcriptional Level ◽

Adult Mice

ABSTRACT The murine hsp70 gene family includes the evolutionarily conserved hsp70.1 andhsp70.3 genes, which are the major proteins induced by heat and other stress stimuli.hsp70.1 andhsp70.3 encode identical proteins which protect cells and facilitate their recovery from stress-induced damage. While the hsp70 gene family has been widely studied and the roles of the proteins it encodes as molecular chaperones in a range of human pathologies are appreciated, little is known about the developmental regulation of hsp70.1 andhsp70.3 expression and the in vivo biological function of their products. To directly study the physiological role of these proteins in vivo, we have generated mice deficient in heat shock protein 70 (hsp70) by replacing thehsp70.1 orhsp70.3 gene with an in-frame β-galactosidase sequence. We report here that the expression ofhsp70.1 andhsp70.3 is developmentally regulated at the transcriptional level, and an overlapping expression pattern for both genes is observed during embryo development and in the tissues of adult mice. hsp70.1 −/− orhsp70.3 −/− mice are viable and fertile, with no obvious morphological abnormalities. In late embryonic stage and adult mice, both genes are expressed constitutively in tissues exposed directly to the environment (the epidermis and cornea) and in certain internal organs (the epithelium of the tongue, esophagus, and forestomach, and the kidney, bladder, and hippocampus). Exposure of mice to thermal stress results in the rapid induction and expression of hsp70, especially in organs not constitutively expressing hsp70 (the liver, pancreas, heart, lung, adrenal cortex, and intestine). Despite functional compensation in the single-gene-deficient mice by the intact homologous gene (i.e.,hsp70.3 inhsp70.1 −/− mice and vice versa), a marked reduction in hsp70 protein expression was observed in tissues under both normal and heat stress conditions. At the cellular level, inactivation of hsp70.1 orhsp70.3 resulted in deficient maintenance of acquired thermotolerance and increased sensitivity to heat stress-induced apoptosis. The additive or synergistic effects exhibited by coexpression of both hsp70 genes, and the evolutionary significance of the presence of both hsp70genes, is hence underlined.

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