scholarly journals Temperature-dependent metabolism in Antarctic fish: Do habitat temperature conditions affect thermal tolerance ranges?

Polar Biology ◽  
2016 ◽  
Vol 40 (1) ◽  
pp. 141-149 ◽  
Author(s):  
Tina Sandersfeld ◽  
Felix C. Mark ◽  
Rainer Knust
Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 278 ◽  
Author(s):  
Vanessa Diniz e Silva ◽  
Marina Vale Beirão ◽  
Danon Clemes Cardoso

Ectothermic organisms, such as insects, are highly temperature dependent and are good models for studies that predict organisms’ responses to global climate change. Predicting how climate change may affect species distributions is a complicated task. However, it is possible to estimate species’ physiological constraints through maximum critical temperature, which may indicate if the species can tolerate new climates. Butterflies are useful organisms for studies of thermal tolerance. We tested if species have different thermal tolerances and if different habitats influence the thermal tolerance of the butterflies present in Brazil’s campo rupestre (open areas) and forest islands (shaded areas). A total of 394 fruit-feeding butterflies, comprising 45 species, were tested. The results separated the species into two statistically different groups: the resistant species with maximum critical temperature of 53.8 ± 7.4 °C, and the non-resistant species with maximum critical temperature of 48.2 ± 7.4 °C. The species of butterflies displayed differences in maximum critical temperature between the campo rupestre and forest islands that can be related to the two distinct habitats, but this did not correlate phylogenetically. Species from the forest islands were also divided into two groups, “resistant” and “non-resistant”, probably due to the heterogeneity of the habitat; the forest islands have a canopy, and in the understory, there are shaded and sunny areas. Species from forest islands, especially species that displayed lower thermal tolerance, may be more susceptible to global warming.


2020 ◽  
Vol 21 (22) ◽  
pp. 8493
Author(s):  
Hiroki Kazama ◽  
Shu-ichiro Kashiwaba ◽  
Sayaka Ishii ◽  
Keiko Yoshida ◽  
Yuta Yatsuo ◽  
...  

Cell division is essential for the maintenance of life and involves chromosome segregation and subsequent cytokinesis. The processes are tightly regulated at both the spatial and temporal level by various genes, and failures in this regulation are associated with oncogenesis. Here, we investigated the gene responsible for defects in cell division by using murine temperature-sensitive (ts) mutant strains, tsFT101 and tsFT50 cells. The ts mutants normally grow in a low temperature environment (32 °C) but fail to divide in a high temperature environment (39 °C). Exome sequencing and over-expression analyses identified Diaph3, a member of the formin family, as the cause of the temperature sensitivity observed in tsFT101 and tsFT50 cells. Interestingly, Diaph3 knockout cells showed abnormality in cytokinesis at 39 °C, and the phenotype was rescued by re-expression of Diaph3 WT, but not Diaph1 and Diaph2, other members of the formin family. Furthermore, Diaph3 knockout cells cultured at 39 °C showed a significant increase in the level of acetylated α-tubulin, an index of stabilized microtubules, and the level was reduced by Diaph3 expression. These results suggest that Diaph3 is required for cytokinesis only under high temperature conditions. Therefore, our study provides a new insight into the mechanisms by which regulatory factors of cell division function in a temperature-dependent manner.


2021 ◽  
Vol 11 ◽  
Author(s):  
Bastian Maus ◽  
Sebastian Gutsfeld ◽  
Christian Bock ◽  
Hans-Otto Pörtner

The thermal tolerance of marine decapod crustacea is defined through their capacities for oxygen uptake and distribution. High ambient CO2 levels were previously shown to reduce hemolymph oxygen levels at enhanced cardiac performance during warming. This study investigated the impacts of warming under two CO2 levels on ventilation and hemolymph circulation in edible crabs Cancer pagurus. It also highlights changes in the ventilatory and cardiac pauses displayed by Decapoda under routine metabolism. Animals were exposed to step-wise, sub-critical warming (12–20°C over 5 days) under control (470 μatm) and high (1,350 μatm) water PCO2. Flow-through respirometry was combined with magnetic resonance imaging and infra-red photoplethysmography to allow for simultaneous, non-invasive measurements of metabolic rates (M˙O2), ventilation and cardiovascular performance. Crabs spent significantly more time in a low M˙O2 state (metabolic pause), when experiencing high CO2 conditions above 16°C, compared to normocapnic warming. Heart rates leveled off beyond 18°C at any CO2 level. Cardiac output continued to increase with high-CO2-warming, due to elevated cardiac stroke volumes. Consequently, temperature-dependent branchial hemolymph flow remained unaffected by CO2. Instead, a suppressing effect of CO2 on ventilation was found beyond 16°C. These results indicate constrained oxygen uptake at stable cardiovascular performance in a decapod crustacean.Cancer pagurus: urn:lsid:zoobank.org:act:B750F89A-84B5-448B-8D80-EBD724A1C9D4


Author(s):  
Mohammad Mahdi Ashrafian ◽  
Seyed Ali Hosseini Kordkheili

Phenomenological constitutive modeling of Ti-6Al-4V at temperatures between 923 and 1023 K under 0.0005–0.05 s−1 quasi-static rates is studied based on a phenomenological approach. For this purpose, the Johnson–Cook constitutive model is revisited. At low temperature conditions under moderate to high strain rates, the material’s stress–strain curves are the most similar to power-law function. Contrary to this, at high temperature conditions under low to moderate strain rates, the saturation-type function well describes the stress–strain curves. On the other hand, it is illustrated that the Johnson–Cook constitutive model is feeble to predict the material’s behavior correctly. Accordingly, in this study, a viscoplastic temperature-dependent constitutive model is developed. The strain rate hardening as well as thermal softening of the developed model is the same as the Johnson–Cook model. But a temperature-dependent strain hardening function is proposed in which both the saturation-type and power-law hardening behaviors of the material are implemented. In comparison with the Johnson–Cook model, the new constitutive model’s fidelity in capturing the titanium behavior is depicted. At last, by considering an Arrhenius-type phenomenological constitutive model, it is noted that the developed constitutive model has the best correctness in predicting the Ti-6Al-4V stress–strain behavior at high temperature conditions under quasi-static rates.


2016 ◽  
Author(s):  
Thomas Enriquez ◽  
Hercé Colinet

The spotted wing Drosophila, Drosophila suzukii, is a new pest in Europe and America which causes severe damages to stone fruits crops. Temperature and humidity are among the most important abiotic factors governing insect life. In many situations, temperature can become stressful thus compromising fitness and survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality of D. suzukii is essential to facilitate management of this pest. The objective of the present study was to investigate D. suzukii basal cold and heat tolerance. Adults and pupae were submitted to six low (-5 to 7.5 °C) and seven high temperatures (30 to 37 °C) for various durations, and survival-time-temperature relationships were investigated. In addition, pupal thermal tolerance was analyzed under low vs. high relative humidity. Our results showed that males had higher cold survival than females, and pupae appeared less cold-tolerant than adults. Above 5 °C, adult cold mortality became minor, even after prolonged exposures (i.e. one month). Males were less heat tolerant than females, and pupae showed a better survival to extreme high temperatures than adults. Low relative humidity did not affect D. suzukii cold survival, but reduced survival under heat stress. Overall, this study shows that survival of D. suzukii under heat and cold conditions depends on both stress intensity and duration, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description of D. suzukii thermal tolerance and limits.


2018 ◽  
Author(s):  
Snigdha Mohan ◽  
Ton G.G. Groothuis ◽  
Chris Vinke ◽  
Jean-Christophe Billeter

AbstractMothers may modulate the phenotype of their offspring by affecting their development based on her own environment. In changing environments, these maternal effects are thought to adjust offspring physiology and development and thus produce offspring better prepared to the environment experienced by the mother. However, evidence for this is scarce. Here we test the consequences of a match or mismatch between mother and offspring temperature conditions on growth, adult morphology and reproduction into the grandchildren generation in the fruit fly Drosophila melanogaster. This experimental design tests the relative contribution of maternal effects and offspring intrinsic plasticity to the phenotypic response to temperature conditions. We manipulated maternal temperature conditions by exposing mothers to either 18°C or 29°C conditions. Their eggs developed at a temperature that was either matched or mismatched with the maternal one. Survival from egg to adult was higher when the maternal and offspring environments matched, showing maternal effects affecting a trait that is a close proxy for fitness. However developmental speed, adult size and fecundity responded to temperature mostly through offspring phenotypic plasticity and maternal effects only had a small contribution. The results provide experimental evidence for maternal effects in influencing a potentially adaptive offspring response to temperature in the model organism Drosophila melanogaster. These effects appear to modulate early embryonic phenotypes such as survival, more than the adult phenotypes of the offspring.


2016 ◽  
Author(s):  
Thomas Enriquez ◽  
Hercé Colinet

The spotted wing Drosophila, Drosophila suzukii, is a new pest in Europe and America which causes severe damages to stone fruits crops. Temperature and humidity are among the most important abiotic factors governing insect life. In many situations, temperature can become stressful thus compromising fitness and survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality of D. suzukii is essential to facilitate management of this pest. The objective of the present study was to investigate D. suzukii basal cold and heat tolerance. Adults and pupae were submitted to six low (-5 to 7.5 °C) and seven high temperatures (30 to 37 °C) for various durations, and survival-time-temperature relationships were investigated. In addition, pupal thermal tolerance was analyzed under low vs. high relative humidity. Our results showed that males had higher cold survival than females, and pupae appeared less cold-tolerant than adults. Above 5 °C, adult cold mortality became minor, even after prolonged exposures (i.e. one month). Males were less heat tolerant than females, and pupae showed a better survival to extreme high temperatures than adults. Low relative humidity did not affect D. suzukii cold survival, but reduced survival under heat stress. Overall, this study shows that survival of D. suzukii under heat and cold conditions depends on both stress intensity and duration, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description of D. suzukii thermal tolerance and limits.


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