1
|
Christoffersen SN, Pertoldi C, Sørensen JG, Kristensen TN, Bruhn D, Bahrndorff S. Strong acclimation effect of temperature and humidity on heat tolerance of the Arctic collembolan Megaphorura arctica. J Exp Biol 2024; 227:jeb247394. [PMID: 38841875 DOI: 10.1242/jeb.247394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/20/2024] [Indexed: 06/07/2024]
Abstract
The Arctic is a highly variable environment in which extreme daily and seasonal temperature fluctuations can occur. With climate change, an increase in the occurrence of extreme high temperatures and drought events is expected. While the effects of cold and dehydration stress on polar arthropods are well studied in combination, little is known about how these species respond to the combined effects of heat and dehydration stress. In this paper, we investigated how the heat tolerance of the Arctic collembola Megaphorura arctica is affected by combinations of different temperature and humidity acclimation regimes under controlled laboratory conditions. The effect of acclimation temperature was complex and highly dependent on both acclimation time and temperature, and was found to have a positive, negative or no effect depending on experimental conditions. Further, we found marked effects of the interaction between temperature and humidity on heat tolerance, with lower humidity severely decreasing heat tolerance when the acclimation temperature was increased. This effect was more pronounced with increasing acclimation time. Lastly, the effect of acclimation on heat tolerance under a fluctuating temperature regime was dependent on acclimation temperature and time, as well as humidity levels. Together, these results show that thermal acclimation alone has moderate or no effect on heat tolerance, but that drought events, likely to be more frequent in the future, in combination with high temperature stress can have large negative impacts on heat tolerance of some Arctic arthropods.
Collapse
Affiliation(s)
| | - Cino Pertoldi
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg East, Denmark
- Aalborg Zoo, Mølleparkvej 63, 9000 Aalborg, Denmark
| | | | | | - Dan Bruhn
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg East, Denmark
| | - Simon Bahrndorff
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg East, Denmark
| |
Collapse
|
2
|
Turriago JL, Tejedo M, Hoyos JM, Camacho A, Bernal MH. The time course of acclimation of critical thermal maxima is modulated by the magnitude of temperature change and thermal daily fluctuations. J Therm Biol 2023; 114:103545. [PMID: 37290261 DOI: 10.1016/j.jtherbio.2023.103545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/09/2023] [Accepted: 03/12/2023] [Indexed: 06/10/2023]
Abstract
Plasticity in the critical thermal maximum (CTmax) helps ectotherms survive in variable thermal conditions. Yet, little is known about the environmental mechanisms modulating its time course. We used the larvae of three neotropical anurans (Boana platanera, Engystomops pustulosus and Rhinella horribilis) to test whether the magnitude of temperature changes and the existence of fluctuations in the thermal environment affected both the amount of change in CTmax and its acclimation rate (i.e., its time course). For that, we transferred tadpoles from a pre-treatment temperature (23 °C, constant) to two different water temperatures: mean (28 °C) and hot (33 °C), crossed with constant and daily fluctuating thermal regimes, and recorded CTmax values, daily during six days. We modeled changes in CTmax as an asymptotic function of time, temperature, and the daily thermal fluctuation. The fitted function provided the asymptotic CTmax value (CTmax∞) and CTmax acclimation rate (k). Tadpoles achieved their CTmax∞ between one and three days. Transferring tadpoles to the hot treatment generated higher CTmax∞ at earlier times, inducing faster acclimation rates in tadpoles. In contrast, thermal fluctuations equally led to higher CTmax∞ values but tadpoles required longer times to achieve CTmax∞ (i.e., slower acclimation rates). These thermal treatments interacted differently with the studied species. In general, the thermal generalist Rhinella horribilis showed the most plastic acclimation rates whereas the ephemeral-pond breeder Engystomops pustulosus, more exposed to heat peaks during larval development, showed less plastic (i.e., canalized) acclimation rates. Further comparative studies of the time course of CTmax acclimation should help to disentangle the complex interplay between the thermal environment and species ecology, to understand how tadpoles acclimate to heat stress.
Collapse
Affiliation(s)
- Jorge L Turriago
- Grupo de Herpetología, Eco-Fisiología & Etología, Department of Biology, Universidad del Tolima, Tolima, 730006299, Colombia; Programa Doctorado en Ciencias Biológicas, Pontificia Universidad Javeriana, Bogotá, 11001000, Colombia.
| | - Miguel Tejedo
- Department of Evolutionary Ecology, Estación Biológica de Doñana, CSIC, Sevilla, 41092, Spain.
| | - Julio M Hoyos
- Grupo UNESIS, Department of Biology, Pontificia Universidad Javeriana, Bogotá, 11001000, Colombia.
| | - Agustín Camacho
- Department of Evolutionary Ecology, Estación Biológica de Doñana, CSIC, Sevilla, 41092, Spain.
| | - Manuel H Bernal
- Grupo de Herpetología, Eco-Fisiología & Etología, Department of Biology, Universidad del Tolima, Tolima, 730006299, Colombia.
| |
Collapse
|
3
|
Perez R, Aron S. Protective role of trehalose in the Namib desert ant, Ocymyrmex robustior. J Exp Biol 2023; 226:286983. [PMID: 36695637 DOI: 10.1242/jeb.245149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/12/2023] [Indexed: 01/26/2023]
Abstract
Over recent decades, increasing attention has been paid to how low-molecular-weight molecules affect thermal tolerance in animals. Although the disaccharide sugar trehalose is known to serve as a thermal protectant in unicellular organisms, nothing is known about its potential role in insects. In this study, we investigated the effect of trehalose on heat tolerance in the Namib desert ant, Ocymyrmex robustior, one of the most thermotolerant animals found in terrestrial ecosystems. First, we tested whether a trehalose-supplemented diet increased worker survival following exposure to heat stress. Second, we assessed the degree of protein damage by comparing protein aggregation levels for trehalose-supplemented workers and control workers. Third, we compared the expression levels of three genes involved in trehalose metabolism. We found that trehalose supplementation significantly enhanced worker heat tolerance, increased metabolic levels of trehalose and reduced protein aggregation under conditions of heat stress. Expression levels of the three genes varied in a manner that was consistent with the maintenance of trehalose in the hemolymph and tissues under conditions of heat stress. Altogether, these results suggest that increased trehalose concentration may help protect Namib desert ant individuals against heat stress. More generally, they highlight the role played by sugar metabolites in boosting tolerance in extremophiles.
Collapse
Affiliation(s)
- Rémy Perez
- Department of Evolutionary Biology & Ecology, Université Libre de Bruxelles, 50 Avenue F. D. Roosevelt, B-1050 Brussels, Belgium
| | - Serge Aron
- Department of Evolutionary Biology & Ecology, Université Libre de Bruxelles, 50 Avenue F. D. Roosevelt, B-1050 Brussels, Belgium
| |
Collapse
|
4
|
Turriago JL, Tejedo M, Hoyos JM, Bernal MH. The effect of thermal microenvironment in upper thermal tolerance plasticity in tropical tadpoles. Implications for vulnerability to climate warming. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:746-759. [PMID: 35674344 DOI: 10.1002/jez.2632] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 04/09/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Current climate change is generating accelerated increase in extreme heat events and organismal plastic adjustments in upper thermal tolerances, (critical thermal maximum -CTmax ) are recognized as the quicker mitigating mechanisms. However, current research casts doubt on the actual mitigating role of thermal acclimation to face heat impacts, due to its low magnitude and weak environmental signal. Here, we examined these drawbacks by first estimating maximum extent of thermal acclimation by examining known sources of variation affecting CTmax expression, such as daily thermal fluctuation and heating rates. Second, we examined whether the magnitude and pattern of CTmax plasticity is dependent of the thermal environment by comparing the acclimation responses of six species of tropical amphibian tadpoles inhabiting thermally contrasting open and shade habitats and, finally, estimating their warming tolerances (WT = CTmax - maximum temperatures) as estimator of heating risk. We found that plastic CTmax responses are improved in tadpoles exposed to fluctuating daily regimens. Slow heating rates implying longer duration assays determined a contrasting pattern in CTmax plastic expression, depending on species environment. Shade habitat species suffer a decline in CTmax whereas open habitat tadpoles greatly increase it, suggesting an adaptive differential ability of hot exposed species to quick hardening adjustments. Open habitat tadpoles although overall acclimate more than shade habitat species, cannot capitalize this beneficial increase in CTmax, because the maximum ambient temperatures are very close to their critical limits, and this increase may not be large enough to reduce acute heat stress under the ongoing global warming.
Collapse
Affiliation(s)
- Jorge L Turriago
- Department of Biology, Grupo de Herpetología, Eco-Fisiología & Etología, Universidad del Tolima, Tolima, Colombia
- Programa de Doctorado en Ciencias Biológicas, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Miguel Tejedo
- Department of Evolutionary Ecology, Estación Biológica de Doñana, CSIC, Sevilla, Spain
| | - Julio M Hoyos
- Department of Biology, Grupo UNESIS, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Manuel H Bernal
- Department of Biology, Grupo de Herpetología, Eco-Fisiología & Etología, Universidad del Tolima, Tolima, Colombia
| |
Collapse
|
5
|
Sandfeld T, Malmos KG, Nielsen CB, Lund MB, Aagaard A, Bechsgaard J, Wurster M, Lalk M, Johannsen M, Vosegaard T, Bilde T, Schramm A. Metabolite Profiling of the Social Spider Stegodyphus dumicola Along a Climate Gradient. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.841490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Animals experience climatic variation in their natural habitats, which may lead to variation in phenotypic responses among populations through local adaptation or phenotypic plasticity. In ectotherm arthropods, the expression of thermoprotective metabolites such as free amino acids, sugars, and polyols, in response to temperature stress, may facilitate temperature tolerance by regulating cellular homeostasis. If populations experience differences in temperatures, individuals may exhibit population-specific metabolite profiles through differential accumulation of metabolites that facilitate thermal tolerance. Such thermoprotective metabolites may originate from the animals themselves or from their associated microbiome, and hence microbial symbionts may contribute to shape the thermal niche of their host. The social spider Stegodyphus dumicola has extremely low genetic diversity, yet it occupies a relatively broad temperature range occurring across multiple climate zones in Southern Africa. We investigated whether the metabolome, including thermoprotective metabolites, differs between populations, and whether population genetic structure or the spider microbiome may explain potential differences. To address these questions, we assessed metabolite profiles, phylogenetic relationships, and microbiomes in three natural populations along a temperature gradient. The spider microbiomes in three genetically distinct populations of S. dumicola showed no significant population-specific pattern, and none of its dominating genera (Borrelia, Diplorickettsia, and Mycoplasma) are known to facilitate thermal tolerance in hosts. These results do not support a role of the microbiome in shaping the thermal niche of S. dumicola. Metabolite profiles of the three spider populations were significantly different. The variation was driven by multiple metabolites that can be linked to temperature stress (e.g., lactate, succinate, or xanthine) and thermal tolerance (e.g., polyols, trehalose, or glycerol): these metabolites had higher relative abundance in spiders from the hottest geographic region. These distinct metabolite profiles are consistent with a potential role of the metabolome in temperature response.
Collapse
|
6
|
Noer NK, Sørensen MH, Colinet H, Renault D, Bahrndorff S, Kristensen TN. Rapid Adjustments in Thermal Tolerance and the Metabolome to Daily Environmental Changes - A Field Study on the Arctic Seed Bug Nysius groenlandicus. Front Physiol 2022; 13:818485. [PMID: 35250620 PMCID: PMC8889080 DOI: 10.3389/fphys.2022.818485] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/03/2022] [Indexed: 11/13/2022] Open
Abstract
Laboratory investigations on terrestrial model-species, typically of temperate origin, have demonstrated that terrestrial ectotherms can cope with daily temperature variations through rapid hardening responses. However, few studies have investigated this ability and its physiological basis in the field. Especially in polar regions, where the temporal and spatial temperature variations can be extreme, are hardening responses expected to be important. Here, we examined diurnal adjustments in heat and cold tolerance in the Greenlandic seed bug Nysius groenlandicus by collecting individuals for thermal assessment at different time points within and across days. We found a significant correlation between observed heat or cold tolerance and the ambient microhabitat temperatures at the time of capture, indicating that N. groenlandicus continuously and within short time-windows respond physiologically to thermal changes and/or other environmental variables in their microhabitats. Secondly, we assessed underlying metabolomic fingerprints using GC-MS metabolomics in a subset of individuals collected during days with either low or high temperature variation. Concentrations of metabolites, including sugars, polyols, and free amino acids varied significantly with time of collection. For instance, we detected elevated sugar levels in animals caught at the lowest daily field temperatures. Polyol concentrations were lower in individuals collected in the morning and evening and higher at midday and afternoon, possibly reflecting changes in temperature. Additionally, changes in concentrations of metabolites associated with energetic metabolism were observed across collection times. Our findings suggest that in these extreme polar environments hardening responses are marked and likely play a crucial role for coping with microhabitat temperature variation on a daily scale, and that metabolite levels are actively altered on a daily basis.
Collapse
Affiliation(s)
- Natasja Krog Noer
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | | | - Hervé Colinet
- UMR 6553, CNRS, Ecosystèmes, Biodiversité, Évolution, University of Rennes 1, Rennes, France
| | - David Renault
- UMR 6553, CNRS, Ecosystèmes, Biodiversité, Évolution, University of Rennes 1, Rennes, France
- Institut Universitaire de France, Paris, France
| | - Simon Bahrndorff
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | | |
Collapse
|
7
|
Dezetter M, Dupoué A, Le Galliard J, Lourdais O. Additive effects of developmental acclimation and physiological syndromes on lifetime metabolic and water loss rates of a dry‐skinned ectotherm. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mathias Dezetter
- CNRS Sorbonne UniversitéUMR 7618iEES ParisUniversité Pierre et Marie Curie Paris France
- Centre d’étude Biologique de Chizé CNRSUMR 7372 Villiers en Bois France
| | - Andréaz Dupoué
- CNRS Sorbonne UniversitéUMR 7618iEES ParisUniversité Pierre et Marie Curie Paris France
| | - Jean‐François Le Galliard
- CNRS Sorbonne UniversitéUMR 7618iEES ParisUniversité Pierre et Marie Curie Paris France
- Ecole Normale SupérieurePSL Research UniversityCNRSUMS 3194Centre de Recherche en Écologie Expérimentale et Prédictive (CEREEP‐Ecotron IleDeFrance) Saint‐Pierre‐lès‐Nemours France
| | - Olivier Lourdais
- Centre d’étude Biologique de Chizé CNRSUMR 7372 Villiers en Bois France
- School of Life Sciences Arizona State University Tempe AZ USA
| |
Collapse
|
8
|
Xia H, Chen L, Fan Z, Peng M, Zhao J, Chen W, Li H, Shi Y, Ding S, Li H. Heat Stress Tolerance Gene FpHsp104 Affects Conidiation and Pathogenicity of Fusarium pseudograminearum. Front Microbiol 2021; 12:695535. [PMID: 34394037 PMCID: PMC8355993 DOI: 10.3389/fmicb.2021.695535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/30/2021] [Indexed: 11/13/2022] Open
Abstract
Heat shock protein Hsp104, a homolog of the bacterial chaperone ClpB and plant Hsp100, plays an essential part in the response to heat and various chemical agents in Saccharomyces cerevisiae. However, their functions remain largely unknown in plant fungal pathogens. Here, we report the identification and functional characterization of a plausible ortholog of yeast Hsp104 in Fusarium pseudograminearum, which we termed FpHsp104. Deletion mutant of FpHsp104 displayed severe defects in the resistance of heat shock during F. pseudograminearum mycelia and conidia when exposed to extreme heat. We also found that the protein showed dynamic localization to small particles under high temperature. However, no significant differences were detected in osmotic, oxidative, or cell wall stress responses between the wild-type and Δfphsp104 strains. Quantitative real-time PCR analysis showed that FpHsp104 was upregulated in the conidia, and disruption of FpHsp104 gene resulted in defects in conidia production, morphology, and germination. The transcript levels of conidiation-related genes of FpFluG, FpVosA, FpWetA, and FpAbaA were reduced in the Δfphsp104 mutant vs. the wild-type strain, but heat-shocked mRNA splicing repair was not affected in Δfphsp104. Moreover, Δfphsp104 mutant also showed attenuated virulence, but its DON synthesis was normal. These data from the first study of Hsp104 in F. pseudograminearum strongly suggest that FpHsp104 gene is an important element in the heat tolerance, development, and pathogenicity processes of F. pseudograminearum.
Collapse
Affiliation(s)
- Huiqing Xia
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Linlin Chen
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China.,National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou, China
| | - Zhuo Fan
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Mengya Peng
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Jingya Zhao
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Wenbo Chen
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Haiyang Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yan Shi
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shengli Ding
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China.,National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou, China
| | - Honglian Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China.,National Key Laboratory of Wheat and Maize Crop Science, Zhengzhou, China
| |
Collapse
|
9
|
Thermal adaptations of adults and eggs in the Arctic seed bug Nysius groenlandicus (Insecta: Hemiptera) from South Greenland. Polar Biol 2021. [DOI: 10.1007/s00300-021-02807-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|