scholarly journals Maximum thermal tolerance trades off with chronic tolerance of high temperature in contrasting thermal populations of Radix balthica

2017 ◽  
Vol 7 (9) ◽  
pp. 3149-3156 ◽  
Author(s):  
Magnus P. Johansson ◽  
Anssi Laurila
Keyword(s):  
High Temperature ◽  
Thermal Tolerance ◽  
Radix Balthica

Toward high-temperature thermal tolerance in solar selective absorber coatings: choosing high entropy ceramic HfNbTaTiZrN

2021 ◽  
Vol 9 (37) ◽  
pp. 21270-21280
Author(s):  
Cheng-Yu He ◽  
Xiang-Hu Gao ◽  
Dong-Mei Yu ◽  
Shuai-Sheng Zhao ◽  
Hui-Xia Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Functional Properties ◽  
Thermal Tolerance ◽  
High Performance ◽  
Configurational Entropy ◽  
High Entropy ◽  
Recent Advances

The most recent advances in high-entropy materials provide impetus for the development of high-performance materials, simultaneously providing high-temperature robustness and excellent functional properties owing to the high configurational entropy and distorted lattices.

scholarly journals Plastic responses of survival and fertility following heat stress in pupal and adult Drosophila virilis

2021 ◽  
Author(s):  
Benjamin Walsh ◽  
Steven Parratt ◽  
Natasha Mannion ◽  
Rhonda Snook ◽  
Amanda Bretman ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Temperature Stress ◽  
High Temperatures ◽  
Male Fertility ◽  
Thermal Tolerance ◽  
Drosophila Virilis ◽  
Life History Stage ◽  
Heat Hardening ◽  
The Impact

The impact of rising global temperatures on survival and reproduction is putting many species at risk of extinction. In particular, it has recently been shown that thermal effects on reproduction, especially limits to male fertility, can underpin species distributions in insects. However, the physiological factors influencing fertility at high temperatures are poorly understood. Key factors that affect somatic thermal tolerance such as hardening, the ability to phenotypically increase thermal tolerance after a mild heat shock, and the differential impact of temperature on different life stages, are largely unexplored for thermal fertility tolerance. Here, we examine the impact of high temperatures on male fertility in the cosmopolitan fruit fly Drosophila virilis. We first determined whether temperature stress at either the pupal or adult life-history stage impacts fertility. We then tested the capacity for heat-hardening to mitigate heat-induced sterility. We found that thermal stress reduces fertility in different ways in pupae and adults. Pupal heat stress delays sexual maturity, whereas males heated as adults can reproduce initially following heat stress, but lose the ability to produce offspring. We also found evidence that while heat-hardening in D. virilis can improve high temperature survival, there is no significant protective impact of this same hardening treatment on fertility. These results suggest that males may be unable to prevent the costs of high temperature stress on fertility through heat-hardening which limits a species’ ability to quickly and effectively reduce fertility loss in the face of short-term high temperature events.

scholarly journals Heat tolerance and thermal preference of the copepod Tigriopus californicus are insensitive to ecologically relevant dissolved oxygen levels

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Khuong V. Dinh ◽  
Arani Y. Cuevas-Sanchez ◽  
Katherine S. Buhl ◽  
Elizabeth A. Moeser ◽  
W. Wesley Dowd
Keyword(s):  
High Temperature ◽  
Dissolved Oxygen ◽  
Thermal Tolerance ◽  
Multiple Stressors ◽  
Interactive Effects ◽  
Egg Mass ◽  
Tigriopus Californicus ◽  
Oxygen Levels ◽  
Behavioral Preference ◽  
Diel Fluctuations

Abstract Shifting climate patterns may impose novel combinations of abiotic conditions on animals, yet understanding of the present-day interactive effects of multiple stressors remains under-developed. We tested the oxygen and capacity limited thermal tolerance (OCLTT) hypothesis and quantified environmental preference of the copepod Tigriopus californicus, which inhabits rocky-shore splashpools where diel fluctuations of temperature and dissolved oxygen (DO) are substantial. Egg-mass bearing females were exposed to a 5 h heat ramp to peak temperatures of 34.1–38.0 °C crossed with each of four oxygen levels: 22, 30, 100 and 250% saturation (4.7–5.3, 5.3–6.4, 21.2–21.3, and 50.7–53.3 kPa). Survival decreased at higher temperatures but was independent of DO. The behavioral preference of females was quantified in seven combinations of gradients of both temperature (11–37 °C) and oxygen saturation (17–206% or 3.6–43.6 kPa). Females avoided high temperatures regardless of DO levels. This pattern was more pronounced when low DO coincided with high temperature. In uniform temperature treatments, the distribution shifted toward high DO levels, especially in uniform high temperature, confirming that Tigriopus can sense environmental pO2. These results question the ecological relevance of OCLTT for Tigriopus and raise the possibility of microhabitat selection being used within splashpool environments to avoid physiologically stressful combinations of conditions.

scholarly journals Spider Mites Singly Infected With Either Wolbachia or Spiroplasma Have Reduced Thermal Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu-Xi Zhu ◽  
Zhang-Rong Song ◽  
Yi-Yin Zhang ◽  
Ary A. Hoffmann ◽  
Xiao-Yue Hong
Keyword(s):  
High Temperature ◽  
Thermal Tolerance ◽  
Spider Mite ◽  
Heat Exposure ◽  
Dependent Manner ◽  
Bacterial Replication ◽  
Lower Temperature ◽  
Temperature Exposure ◽  
Temperature Impacts ◽  
The Impact

Heritable symbionts play an essential role in many aspects of host ecology in a temperature-dependent manner. However, how temperature impacts the host and their interaction with endosymbionts remains largely unknown. Here, we investigated the impact of moderate (20°C) and high (30 and 35°C) temperatures on symbioses between the spider mite Tetranychus truncatus and two maternally inherited endosymbionts (Wolbachia and Spiroplasma). We found that the thermal tolerance of mites (as measured by survival after heat exposure) was lower for mites that were singly infected with either Wolbachia or Spiroplasma than it was for co-infected or uninfected mites. Although a relatively high temperature (30°C) is thought to promote bacterial replication, rearing at high temperature (35°C) resulted in losses of Wolbachia and particularly Spiroplasma. Exposing the mites to 20°C reduced the density and transmission of Spiroplasma but not Wolbachia. The four spider mite strains tested differed in the numbers of heat shock genes (Hsps) induced under moderate or high temperature exposure. In thermal preference (Tp) assays, the two Wolbachia-infected spider mite strains preferred a lower temperature than strains without Wolbachia. Our results show that endosymbiont-mediated spider mite responses to temperature stress are complex, involving a combination of changing endosymbiont infection patterns, altered thermoregulatory behavior, and transcription responses.

scholarly journals Hypoxia inducible factor-1 α knockout does not impair acute thermal tolerance or heat hardening in zebrafish

2020 ◽  
Vol 16 (7) ◽  
pp. 20200292
Author(s):  
William Joyce ◽  
Steve F. Perry
Keyword(s):  
High Temperature ◽  
Thermal Tolerance ◽  
Hypoxia Inducible Factor ◽  
Extreme Environments ◽  
Hypoxia Tolerance ◽  
Similar Degree ◽  
Wild Type ◽  
Double Knockout ◽  
Hypoxia Inducible Factor 1 ◽  
Heat Hardening

The rapid increase in critical thermal maximum (CT max ) in fish (or other animals) previously exposed to critically high temperature is termed ‘heat hardening’, which likely represents a key strategy to cope with increasingly extreme environments. The physiological mechanisms that determine acute thermal tolerance, and the underlying pathways facilitating heat hardening, remain debated. It has been posited, however, that exposure to high temperature is associated with tissue hypoxia and may be associated with the increased expression of hypoxia-inducible factor-1 (Hif-1). We studied acute thermal tolerance in zebrafish ( Danio rerio ) lacking functional Hif-1 α paralogs (Hif-1aa and Hif-1ab double knockout; Hif-1 α −/− ), which are known to exhibit markedly reduced hypoxia tolerance. We hypothesized that Hif-1 α −/− zebrafish would suffer reduced acute thermal tolerance relative to wild type and that the heat hardening ability would be lost. However, on the contrary, we observed that Hif-1 α −/− and wild-type fish did not differ in CT max , and both genotypes exhibited heat hardening of a similar degree when CT max was re-tested 48 h later. Despite exhibiting impaired hypoxia tolerance, Hif-1 α −/− zebrafish display unaltered thermal tolerance, suggesting that these traits are not necessarily functionally associated. Hif-1 α is accordingly not required for short-term acclimation in the form of heat hardening.

scholarly journals A guaB Mutant Strain of Rhizobium tropici CIAT899 Pleiotropically Defective in Thermal Tolerance and Symbiosis

2000 ◽  
Vol 13 (11) ◽  
pp. 1228-1236 ◽  
Author(s):  
Pablo M. Riccillo ◽  
Monica M. Collavino ◽  
Daniel H. Grasso ◽  
Reg England ◽  
Frans J. de Bruijn ◽  
...  
Keyword(s):  
High Temperature ◽  
Mutant Strain ◽  
Thermal Tolerance ◽  
Alternative Pathway ◽  
Thermal Sensitivity ◽  
Inosine Monophosphate Dehydrogenase ◽  
Rhizobium Tropici ◽  
Inosine Monophosphate ◽  
Transposon Insertion ◽  
Monophosphate Dehydrogenase

Rhizobium tropici strain CIAT899 displays a high intrinsic thermal tolerance, and had been used in this work to study the molecular basis of bacterial responses to high temperature. We generated a collection of R. tropici CIAT899 mutants affected in thermal tolerance using Tn5-luxAB mutagenesis and described the characterization of a mutant strain, CIAT899-10T, that fails to grow under conditions of high temperature. Strain CIAT899-10T carries a single transposon insertion in a gene showing a high degree of similarity with the guaB gene of Escherichia coli and other organisms, encoding the enzyme inosine monophosphate dehydrogenase. The guaB strain CIAT899-10T does not require guanine for growth due to an alternative pathway via xanthine dehydrogenase and, phenotypically, in addition to the thermal sensitivity, the mutant is also defective in symbiosis with beans, forming nodules that lack rhizobial content. Guanine and its precursors restore wild-type tolerance to grow at high temperature. Our data show that, in R. tropici, the production of guanine via inosine monophosphate dehydrogenase is essential for growth at extreme temperatures and for effective nodulation.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

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