scholarly journals A positive genetic correlation between hypoxia tolerance and heat tolerance supports a controversial theory of heat stress

2017 ◽  
Vol 13 (11) ◽  
pp. 20170309 ◽  
Author(s):  
Collin Teague ◽  
Jacob P. Youngblood ◽  
Kinley Ragan ◽  
Michael J. Angilletta ◽  
John M. VandenBrooks
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Stress ◽  
Genetic Correlation ◽  
Heat Tolerance ◽  
Quantitative Genetics ◽  
Thermal Tolerance ◽  
Model Organism ◽  
Hypoxia Tolerance ◽  
Hypoxic Stress ◽  
Adaptation To Heat

We used quantitative genetics to test a controversial theory of heat stress, in which animals overheat when the demand for oxygen exceeds the supply. This theory, referred to as oxygen- and capacity-limited thermal tolerance, predicts a positive genetic correlation between hypoxia tolerance and heat tolerance. We demonstrate the first genetic correlation of this kind in a model organism, Drosophila melanogaster . Genotypes more likely to fly under hypoxic stress (12% O 2 ) were also more likely to fly under heat stress (39°C). This finding prompts new questions about mechanisms and limits of adaptation to heat stress.

scholarly journals Gut Microbiota of Drosophila subobscura Contributes to Its Heat Tolerance and Is Sensitive to Transient Thermal Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Angélica Jaramillo ◽  
Luis E. Castañeda
Keyword(s):  
Heat Stress ◽  
Community Structure ◽  
Thermal Stress ◽  
Gut Microbiota ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Drosophila Subobscura ◽  
Transient Thermal ◽  
The Impact

The gut microbiota can contribute to host physiology leading to an increase of resistance to abiotic stress conditions. For instance, temperature has profound effects on ectotherms, and the role of the gut microbiota on the thermal tolerance of ectotherms is a matter of recent research. However, most of these studies have been focused on single static temperatures instead of evaluating thermal tolerance in a wide range of stressful temperatures. Additionally, there is evidence supporting that the gut microbiota is sensitive to environmental temperature, which induces changes in its composition and diversity. These studies have evaluated the effects of thermal acclimation (>2 weeks) on the gut microbiota, but we know little about the impact of transient thermal stress on the composition and diversity of the gut microbiota. Thus, we investigated the role of the gut microbiota on the heat tolerance of Drosophila subobscura by measuring the heat tolerance of conventional and axenic flies exposed to different heat stressful temperatures (35, 36, 37, and 38°C) and estimating the heat tolerance landscape for both microbiota treatments. Conventional flies exposed to mild heat conditions exhibited higher thermal tolerance than axenic flies, whereas at higher stressful temperatures there were no differences between axenic and conventional flies. We also assessed the impact of transient heat stress on the taxonomical abundance, diversity, and community structure of the gut microbiota, comparing non-stressed flies (exposed to 21°C) and heat-stressed flies (exposed to 34°C) from both sexes. Bacterial diversity indices, bacterial abundances, and community structure changed between non-stressed and heat-stressed flies, and this response was sex-dependent. In general, our findings provide evidence that the gut microbiota influences heat tolerance and that heat stress modifies the gut microbiota at the taxonomical and structural levels. These results demonstrate that the gut microbiota contributes to heat tolerance and is also highly sensitive to transient heat stress, which could have important consequences on host fitness, population risk extinction, and the vulnerability of ectotherms to current and future climatic conditions.

scholarly journals Disparate patterns of thermal adaptation between life stages in temperate vs. tropical Drosophila melanogaster

2017 ◽  
Author(s):  
Brent L. Lockwood ◽  
Tarun Gupta ◽  
Rosemary Scavotto
Keyword(s):  
Climate Change ◽  
Drosophila Melanogaster ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Life Stage ◽  
Thermal Adaptation ◽  
Life Stages ◽  
Thermal Limits ◽  
Heat Tolerant ◽  
Selection For

AbstractMany terrestrial ectothermic species exhibit limited variation in upper thermal tolerance across latitude. However, these trends may not signify limited adaptive capacity to increase thermal tolerance in the face of climate change. Instead, thermal tolerance may be similar among populations because behavioral thermoregulation by mobile organisms or life stages may buffer natural selection for thermal tolerance. We compared thermal tolerance of adults and embryos among natural populations of Drosophila melanogaster from a broad range of thermal habitats around the globe to assess natural variation of thermal tolerance in mobile vs. immobile life stages. We found no variation among populations in adult thermal tolerance, but embryonic thermal tolerance was higher in tropical strains than in temperate strains. Average maximum temperature of the warmest month of the year predicted embryonic thermal tolerance in tropical but not temperate sites. We further report that embryos live closer to their upper thermal limits than adultso—i.e., thermal safety margins are smaller for embryos than adults. F1 hybrid embryos from crosses between temperate and tropical populations had thermal tolerance that matched that of tropical embryos, suggesting dominance of heat-tolerant alleles. Together our findings suggest that thermal selection has led to divergence in embryonic thermal tolerance but that selection for divergent thermal tolerance may be limited in adults. Further, our results suggest that thermal traits should be measured across life stages in order to better predict adaptive limits.Impact SummaryClimate change may threaten the extinction of many ectothermic species, unless populations can evolutionarily adapt to rising temperatures. Natural selection should favor individuals with higher heat tolerances in hotter environments. But recent studies have found that individuals from hot and cold places often have similar heat tolerances. This pattern may indicate that the evolution of heat tolerance is constrained. If this were true, then it would have dire consequences for species persistence under novel thermal conditions.An alternative explanation for lack of variation in heat tolerance is that mobile organisms don’t need higher heat tolerances to survive in hotter places. The majority of studies have focused on heat tolerance of the adult life stage. Yet, adults in many species are mobile organisms that can avoid extreme heat by seeking shelter in cooler microhabitats (e.g., shaded locations). In contrast, immobile life stages (e.g., insect eggs) cannot behaviorally avoid extreme heat. Thus, mobile and immobile life stages may face different thermal selection pressures that lead to disparate patterns of thermal adaptation across life stages.Here, we compared heat tolerances of fruit fly adults and eggs (Drosophila melanogaster) from populations in temperate North America and tropical locations around the globe. Consistent with previous studies, we found no differences among populations in adult heat tolerance. However, eggs from tropical flies were consistently more heat tolerant than eggs from North American flies. Further, eggs had lower heat tolerance than adults. Consequently, fly eggs in the hotter tropics may experience heat death more frequently than adult flies later in life. This may explain why patterns of divergence in heat tolerance were decoupled across life stages. These patterns indicate that thermal adaptation may be life-stage-specific and suggest that future work should characterize thermal traits across life stages to better understand the evolution of thermal limits.

scholarly journals Oxygen supply limits the heat tolerance of locusts during the first instar only

2020 ◽  
Author(s):  
Jacob P. Youngblood ◽  
John M. VandenBrooks ◽  
Oluwatosin Babarinde ◽  
Megan E. Donnay ◽  
Deanna B. Elliott ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Oxygen Supply ◽  
Oxygen Limitation ◽  
Life Stages ◽  
First Instar ◽  
Wide Range ◽  
Survival And Reproduction ◽  
Respiratory Systems

AbstractExtreme heat directly limits an organism’s survival and reproduction, but scientists cannot agree on what causes organisms to lose function or die during heating. According to the theory of oxygen- and capacity-limitation of thermal tolerance, heat stress occurs when a warming organism’s demand for oxygen exceeds its supply, triggering a widespread drop in ATP concentration. This model predicts that an organism’s heat tolerance should decrease under hypoxia, yet most terrestrial organisms tolerate the same amount of warming across a wide range of oxygen concentrations. This point is especially true for adult insects, who deliver oxygen through highly efficient respiratory systems. However, oxygen limitation at high temperatures may be more common during immature life stages, which have less developed respiratory systems. To test this hypothesis, we measured the effects of heat and hypoxia on the survival of locusts (Schistocerca cancellata) throughout development. We demonstrate that the heat tolerance of locusts depends on oxygen supply during the first instar but not during later instars. This finding provides further support for the idea that oxygen limitation of thermal tolerance depends on respiratory performance, especially during immature life stages.

scholarly journals Interactions between developmental and adult acclimation have distinct consequences for heat-tolerance and heat-stress recovery

2021 ◽  
Author(s):  
Quentin Willot ◽  
Ben Loos ◽  
John S. Terblanche
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Climatic Conditions ◽  
Distinct Pattern ◽  
Recovery Rates ◽  
Relative Contribution ◽  
Heat Hardening ◽  
Full Factorial Experimental Design ◽  
Post Stress

Developmental and adult thermal acclimation can have distinct, even opposite, effects on adult heat resistance in ectotherms. Yet, their relative contribution to heat-hardiness of ectotherms remains unclear despite the broad ecological implications thereof. Furthermore, the deterministic relationship between heat-knockdown and recovery from heat stress is poorly understood but significant for establishing causal links between climate variability and population dynamics. Here, using D. melanogaster in a full-factorial experimental design, we assess flies heat-tolerance in static stress assays, and document how developmental and adult acclimation interact with a distinct pattern to promote survival to heat-stress in adults. We show that warmer adult acclimation is the initial factor enhancing survival to constant stressful high temperatures in flies, but also that the interaction between adult and developmental acclimation becomes gradually more important to ensure survival as the stress persists. This provides an important framework revealing the dynamic interplay between these two forms of acclimation, that ultimately enhance thermal tolerance as a function of stress duration. Furthermore, by investigating recovery rates post-stress, we also show that the process of heat-hardening and recovery post heat knockdown are likely to be based on set of (at least partially) divergent mechanisms. This could bear ecological significance as a tradeoff may exist between increasing thermal tolerance and maximizing recovery rates post-stress, constraining population responses when exposed to variable and stressful climatic conditions.

scholarly journals Thermal Inactivation of Susceptible and Multiantimicrobial-Resistant Salmonella Strains Grown in the Absence or Presence of Glucose

2003 ◽  
Vol 69 (7) ◽  
pp. 4123-4128 ◽  
Author(s):  
R. T. Bacon ◽  
J. R. Ransom ◽  
J. N. Sofos ◽  
P. A. Kendall ◽  
K. E. Belk ◽  
...  
Keyword(s):  
Heat Stress ◽  
Protective Effect ◽  
Thermal Tolerance ◽  
Thermal Inactivation ◽  
Survival Curves ◽  
Acid Adaptation ◽  
Circulating Water ◽  
Glucose Levels ◽  
Study Results ◽  
Peptone Water

ABSTRACT The heat resistance of susceptible and multiantimicrobial-resistant Salmonella strains grown to stationary phase in glucose-free tryptic soy broth supplemented with 0.6% yeast extract (TSBYE−G; nonadapted), in regular (0.25% glucose) TSBYE, or in TSBYE−G with 1.00% added glucose (TSBYE+G; acid adapted) was determined at 55, 57, 59, and 61°C. Cultures were heated in sterile 0.1% buffered peptone water (50 μl) in heat-sealed capillary tubes immersed in a thermostatically controlled circulating-water bath. Decimal reduction times (D values) were calculated from survival curves having r 2 values of >0.90 as a means of comparing thermal tolerance among variables. D 59°C values increased (P < 0.05) from 0.50 to 0.58 to 0.66 min for TSBYE−G, TSBYE, and TSBYE+G cultures, respectively. D 61°C values of antimicrobial-susceptible Salmonella strains increased (P < 0.05) from 0.14 to 0.19 as the glucose concentration increased from 0.00 to 1.00%, respectively, while D 61°C values of multiantimicrobial-resistant Salmonella strains did not differ (P > 0.05) between TSBYE−G and TSBYE+G cultures. When averaged across glucose levels and temperatures, there were no differences (P > 0.05) between the D values of susceptible and multiantimicrobial-resistant inocula. Collectively, D values ranged from 4.23 to 5.39, 1.47 to 1.81, 0.50 to 0.66, and 0.16 to 0.20 min for Salmonella strains inactivated at 55, 57, 59, and 61°C, respectively. zD values were 1.20, 1.48, and 1.49°C for Salmonella strains grown in TSBYE+G, TSBYE, and TSBYE−G, respectively, while the corresponding activation energies of inactivation were 497, 493, and 494 kJ/mol. Study results suggested a cross-protective effect of acid adaptation on thermal inactivation but no association between antimicrobial susceptibility and the ability of salmonellae to survive heat stress.

scholarly journals FlyBase: updates to the Drosophila melanogaster knowledge base

2020 ◽  
Vol 49 (D1) ◽  
pp. D899-D907 ◽  
Author(s):  
Aoife Larkin ◽  
Steven J Marygold ◽  
Giulia Antonazzo ◽  
Helen Attrill ◽  
Gilberto dos Santos ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Knowledge Base ◽  
Fast Track ◽  
Model Organism ◽  
Disease Models ◽  
Online Database ◽  
Experimental Tool

Abstract FlyBase (flybase.org) is an essential online database for researchers using Drosophila melanogaster as a model organism, facilitating access to a diverse array of information that includes genetic, molecular, genomic and reagent resources. Here, we describe the introduction of several new features at FlyBase, including Pathway Reports, paralog information, disease models based on orthology, customizable tables within reports and overview displays (‘ribbons’) of expression and disease data. We also describe a variety of recent important updates, including incorporation of a developmental proteome, upgrades to the GAL4 search tab, additional Experimental Tool Reports, migration to JBrowse for genome browsing and improvements to batch queries/downloads and the Fast-Track Your Paper tool.

scholarly journals Genotype-by-environment interaction in Holstein heifer fertility traits using single-step genomic reaction norm models

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rui Shi ◽  
Luiz Fernando Brito ◽  
Aoxing Liu ◽  
Hanpeng Luo ◽  
Ziwei Chen ◽  
...  
Keyword(s):  
Heat Stress ◽  
Dairy Cattle ◽  
Candidate Genes ◽  
Heat Tolerance ◽  
Reaction Norm ◽  
Single Step ◽  
Conception Rate ◽  
Critical Periods ◽  
Genotype By Environment ◽  
Fertility Traits

Abstract Background The effect of heat stress on livestock production is a worldwide issue. Animal performance is influenced by exposure to harsh environmental conditions potentially causing genotype-by-environment interactions (G × E), especially in highproducing animals. In this context, the main objectives of this study were to (1) detect the time periods in which heifer fertility traits are more sensitive to the exposure to high environmental temperature and/or humidity, (2) investigate G × E due to heat stress in heifer fertility traits, and, (3) identify genomic regions associated with heifer fertility and heat tolerance in Holstein cattle. Results Phenotypic records for three heifer fertility traits (i.e., age at first calving, interval from first to last service, and conception rate at the first service) were collected, from 2005 to 2018, for 56,998 Holstein heifers raised in 15 herds in the Beijing area (China). By integrating environmental data, including hourly air temperature and relative humidity, the critical periods in which the heifers are more sensitive to heat stress were located in more than 30 days before the first service for age at first calving and interval from first to last service, or 10 days before and less than 60 days after the first service for conception rate. Using reaction norm models, significant G × E was detected for all three traits regarding both environmental gradients, proportion of days exceeding heat threshold, and minimum temperature-humidity index. Through single-step genome-wide association studies, PLAG1, AMHR2, SP1, KRT8, KRT18, MLH1, and EOMES were suggested as candidate genes for heifer fertility. The genes HCRTR1, AGRP, PC, and GUCY1B1 are strong candidates for association with heat tolerance. Conclusions The critical periods in which the reproductive performance of heifers is more sensitive to heat stress are trait-dependent. Thus, detailed analysis should be conducted to determine this particular period for other fertility traits. The considerable magnitude of G × E and sire re-ranking indicates the necessity to consider G × E in dairy cattle breeding schemes. This will enable selection of more heat-tolerant animals with high reproductive efficiency under harsh climatic conditions. Lastly, the candidate genes identified to be linked with response to heat stress provide a better understanding of the underlying biological mechanisms of heat tolerance in dairy cattle.

An ER–Golgi Tethering Factor SLOH4/MIP3 Is Involved in Long-term Heat Tolerance of Arabidopsis

2020 ◽  
Author(s):  
Kazuho Isono ◽  
Ryo Tsukimoto ◽  
Satoshi Iuchi ◽  
Akihisa Shinozawa ◽  
Izumi Yotsui ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Secretory Proteins ◽  
Wild Type ◽  
Additional Function ◽  
Transcript Levels ◽  
Unfolded Protein ◽  
In The Wild ◽  
Protein Response

Abstract Plants are often exposed not only to short-term (S-) heat stress but also to diurnal long-term (L-) heat stress over several consecutive days. To reveal the mechanisms underlying L-heat stress tolerance, we here used a forward genetic screening for sensitive to long-term heat (sloh) mutants and isolated sloh4. The mutant was hypersensitive to L- but not S-heat stress. The causal gene of sloh4 was identical to MIP3 encoding a member of the MAIGO2 (MAG2) tethering complex, which is composed of the MAG2, MIP1, MIP2, and MIP3 subunits and is localized at the endoplasmic reticulum (ER) membrane. Although sloh4/mip3 was hypersensitive to L-heat stress, the sensitivity of the mag2-3 and mip1–1 mutants was similar to that of the wild type. Under L-heat stress, the ER stress and the following unfolded protein response (UPR) were more pronounced in sloh4 than in the wild type. Transcript levels of bZIP60-regulated UPR genes were strongly increased in sloh4 under L-heat stress. Two processes known to be mediated by INOSITOL REQUIRING ENZYME1 (IRE1)—accumulation of the spliced bZIP60 transcript and a decrease in the transcript levels of PR4 and PRX34, encoding secretory proteins—were observed in sloh4 in response to L-heat stress. These findings suggest that misfolded proteins generated in sloh4 under L-heat stress may be recognized by IRE1 but not bZIP28, resulting in initiation of the UPR via activated bZIP60. Therefore, it would be possible that only MIP3 in MAG2 complex has an additional function in L-heat tolerance, which is not related to the ER–Golgi vesicle tethering.

scholarly journals Heat-tolerant hot pepper exhibits constant photosynthesis via increased transpiration rate, high proline content and fast recovery in heat stress condition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sherzod Nigmatullayevich Rajametov ◽  
Eun Young Yang ◽  
Myeong Cheoul Cho ◽  
Soo Young Chae ◽  
Hyo Bong Jeong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Stress ◽  
Heat Tolerance ◽  
Transpiration Rate ◽  
Stress Condition ◽  
Proline Content ◽  
Hot Pepper ◽  
Fast Recovery ◽  
Heat Stress Condition ◽  
Heat Tolerant

AbstractUnderstanding the mechanism for heat tolerance is important for the hot pepper breeding program to develop heat-tolerant cultivars in changing climate. This study was conducted to investigate physiological and biochemical parameters related to heat tolerance and to determine leaf heat damage levels critical for selecting heat-tolerant genotypes. Seedlings of two commercial cultivars, heat-tolerant ‘NW Bigarim’ (NB) and susceptible ‘Chyung Yang’ (CY), were grown in 42 °C for ten days. Photosynthesis, electrolyte conductivity, proline content were measured among seedlings during heat treatment. Photosynthetic rate was significantly reduced in ‘CY’ but not in ‘NB’ seedlings in 42 °C. Stomatal conductivity and transpiration rate was significantly higher in ‘NB’ than ‘CY’. Proline content was also significantly higher in ‘NB’. After heat treatment, leaf heat damages were determined as 0, 25, 50 and 75% and plants with different leaf heat damages were moved to a glasshouse (30–32/22–24 °C in day/night). The growth and developmental parameters were investigated until 70 days. ‘NB’ was significantly affected by leaf heat damages only in fruit yield while ‘CY’ was in fruit set, number and yield. ‘NB’ showed fast recovery after heat stress compared to ‘CY’. These results suggest that constant photosynthetic rate via increased transpiration rate as well as high proline content in heat stress condition confer faster recovery from heat damage of heat-tolerant cultivars in seedlings stages.

scholarly journals Genotype and Trait Specific Responses to Rapamycin Intake in Drosophila melanogaster

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 474
Author(s):  
Palle Duun Rohde ◽  
Asbjørn Bøcker ◽  
Caroline Amalie Bastholm Jensen ◽  
Anne Louise Bergstrøm ◽  
Morten Ib Juul Madsen ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Stress ◽  
Side Effects ◽  
Protein Kinase ◽  
Stress Tolerance ◽  
Treated Group ◽  
Model System ◽  
Treatment Efficiency ◽  
Evolutionarily Conserved ◽  
Heat Stress Tolerance

Rapamycin is a powerful inhibitor of the TOR (Target of Rapamycin) pathway, which is an evolutionarily conserved protein kinase, that plays a central role in plants and animals. Rapamycin is used globally as an immunosuppressant and as an anti-aging medicine. Despite widespread use, treatment efficiency varies considerably across patients, and little is known about potential side effects. Here we seek to investigate the effects of rapamycin by using Drosophila melanogaster as model system. Six isogenic D. melanogaster lines were assessed for their fecundity, male longevity and male heat stress tolerance with or without rapamycin treatment. The results showed increased longevity and heat stress tolerance for male flies treated with rapamycin. Conversely, the fecundity of rapamycin-exposed individuals was lower than for flies from the non-treated group, suggesting unwanted side effects of the drug in D. melanogaster. We found strong evidence for genotype-by-treatment interactions suggesting that a ‘one size fits all’ approach when it comes to treatment with rapamycin is not recommendable. The beneficial responses to rapamycin exposure for stress tolerance and longevity are in agreement with previous findings, however, the unexpected effects on reproduction are worrying and need further investigation and question common believes that rapamycin constitutes a harmless drug.

Sign in / Sign up

Export Citation Format

Share Document