Cellular hallmarks reveal restricted aerobic metabolism at thermal limits
نویسندگان
چکیده
All organisms live within a given thermal range, but little is known about the mechanisms setting the limits of this range. We uncovered cellular features exhibiting signature changes at thermal limits in Caenorhabditis elegans embryos. These included changes in embryo size and shape, which were also observed in Caenorhabditis briggsae, indicating evolutionary conservation. We hypothesized that such changes could reflect restricted aerobic capacity at thermal limits. Accordingly, we uncovered that relative respiration in C. elegans embryos decreases at the thermal limits as compared to within the thermal range. Furthermore, by compromising components of the respiratory chain, we demonstrated that the reliance on aerobic metabolism is reduced at thermal limits. Moreover, embryos thus compromised exhibited signature changes in size and shape already within the thermal range. We conclude that restricted aerobic metabolism at the thermal limits contributes to setting the thermal range in a metazoan organism.
منابع مشابه
Climate variations and the physiological basis of temperature dependent biogeography: systemic to molecular hierarchy of thermal tolerance in animals.
The physiological mechanisms limiting and adjusting cold and heat tolerance have regained interest in the light of global warming and associated shifts in the geographical distribution of ectothermic animals. Recent comparative studies, largely carried out on marine ectotherms, indicate that the processes and limits of thermal tolerance are linked with the adjustment of aerobic scope and capaci...
متن کاملHyperthermic Overdrive: Oxygen Delivery does Not Limit Thermal Tolerance in Drosophila melanogaster
The causes of thermal tolerance limits in animals are controversial. In many aquatic species, it is thought that the inability to deliver sufficient oxygen at high temperatures is more critical than impairment of molecular functions of the mitochondria. However, terrestrial insects utilize a tracheal system, and the concept of a mismatch between metabolic demand and circulatory performance migh...
متن کاملMetabolic and molecular stress responses of sublittoral bearded horse mussel Modiolus barbatus to warming sea water: implications for vertical zonation.
The present study set out to investigate the thermal limits of the Mediterranean bivalve Modiolus barbatus, acclimated to various temperatures, and includes a comparison of laboratory determined limits with its temperature-dependent restriction to deeper water layers in its natural habitat. Thermal responses and limits were determined by integrating information from various levels of biological...
متن کاملThe trade-off between heat tolerance and metabolic cost drives the bimodal life strategy at the air-water interface
The principle of oxygen and capacity limitation of thermal tolerance in ectotherms suggests that the long-term upper limits of an organism's thermal niche are equivalent to the upper limits of the organism's functional capacity for oxygen provision to tissues. Air-breathing ectotherms show wider thermal tolerances, since they can take advantage of the higher availability of oxygen in air than i...
متن کاملThermal adaptation in the intertidal snail Echinolittorina malaccana contradicts current theory by revealing the crucial roles of resting metabolism.
Contemporary theory for thermal adaptation of ectothermic metazoans focuses on the maximization of energy gain and performance (locomotion and foraging). Little consideration is given to the selection for mechanisms that minimize resting energy loss in organisms whose energy gain is severely constrained. We tested a hypothetical framework for thermal performance of locomotor activity (a proxy f...
متن کامل