Journal of thermal biology最新文献

{"title":"Impact of prenatal heat tolerance in holstein dry cows on their calves' thermoregulation and immunity","authors":"Xiaoyang Chen ,&nbsp;Chenyang Li ,&nbsp;Tingting Fang ,&nbsp;Junhu Yao ,&nbsp;Xianhong Gu","doi":"10.1016/j.jtherbio.2024.104015","DOIUrl":"10.1016/j.jtherbio.2024.104015","url":null,"abstract":"<div><div>This study examines the impact of Holstein dry cows' prenatal heat tolerance (n = 180) on their calves' thermoregulation and immunity. Holstein cows (body condition score 3.29 ± 0.39, parity 2.64 ± 0.79) were monitored for body temperature (BT), respiratory rate (RR), and microenvironmental temperature and humidity twice daily for seven days during heat stress. Mixed-effects model and cluster method identified heat-tolerant (n = 68) and heat-sensitive (n = 114) dry cows. Once cows gave birth, the RR and BT of 2-day-old calves were recorded every 2 h for two days, totaling five measurements per day, to assess thermoregulatory responses using generalized linear mixed models. Calves in the heat-tolerant group had a better thermoregulatory response than the heat-sensitive group, RR of heat-tolerant calves was significantly higher than the heat-sensitive calves (<em>P</em> = 0.02). Plasma indicators were analyzed to assess calf immunity. Heat-tolerant calves had significantly lower plasma cortisol, tumor necrosis factor-alpha, interleukin 2, interleukin 4, interleukin 6, and interleukin 10 concentrations compared to heat-sensitive calves (<em>P</em> &lt; 0.05). In both cows and calves, plasma cortisol concentrations in the heat-tolerant groups were lower than those in heat-sensitive groups. In comparison, plasma heat shock protein 70 and heat shock protein 90 concentrations were higher (<em>P</em> &lt; 0.05). In conclusion, calves born to heat-tolerant cows had higher thermoregulation and immunity than calves born to heat-sensitive cows when exposed to heat stress.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"127 ","pages":"Article 104015"},"PeriodicalIF":2.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142837301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative analysis of thermoregulation models to assess heat strain in moderate to extreme heat","authors":"Ankit Joshi ,&nbsp;Bryce Twidwell ,&nbsp;Michael Park ,&nbsp;Konrad Rykaczewski","doi":"10.1016/j.jtherbio.2024.104035","DOIUrl":"10.1016/j.jtherbio.2024.104035","url":null,"abstract":"<div><div>As global temperatures rise due to climate change, the frequency and intensity of heatwaves are increasing, posing significant threats to human health, productivity, and well-being. Thermoregulation models are important tools for quantifying the risk of extreme heat, providing insights into physiological strain indicators such as core and skin temperatures, sweat rates, and thermal comfort levels. This study evaluated four thermoregulation models of varying complexity, differentiated by the geometry and underlying thermoregulatory mechanisms. The models assessed include the Gagge two-node model, the Stolwijk-1971 model, the JOS3 model, and the UTCI-Fiala model. Additionally, we introduce the Stolwijk-2024 model, a modified version of the original Stolwijk model, which incorporates updated empirical coefficients derived from recent studies while retaining the original framework. The models were tested against human trial data across a wide range of extreme heat exposures, including transient extreme heat, humid heat, various physical activity levels, and clothing insulation scenarios. Our findings demonstrate that multi-node and multi-segment models, such as JOS3, UTCI-Fiala, and Stolwijk-2024, reliably predict core (average RMSD: &lt;0.3 °C) and skin (average root-mean-square deviation, RMSD: &lt;0.6 °C) temperatures, making them suitable for assessing heat strain and thermal comfort in moderate to extreme environmental conditions. In contrast, simpler models like the single-segment, two-node Gagge's model performed poorly in predicting core temperature under conditions involving high metabolic rates (&gt;3.75 met) in moderate to hot environments (&gt;35 °C), with an average RMSD of 1.2 °C. Similarly, the Stolwijk-1971 model showed a systematic bias (∼0.45 °C), underpredicting core temperatures during high metabolic rates. This study underscores the robustness and applicability of open-source models like JOS3 and Stolwijk-2024 in public health, urban design, and climate impact research, highlighting their potential to improve our understanding of heat strain and thermal comfort in the context of a warming climate.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"127 ","pages":"Article 104035"},"PeriodicalIF":2.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142909867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of repeated hot water immersion on vascular function, blood pressure and central haemodynamics in individuals with type 2 diabetes mellitus","authors":"Thomas J. James ,&nbsp;Jo Corbett ,&nbsp;Michael Cummings ,&nbsp;Sharon Allard ,&nbsp;Stephen J. Bailey ,&nbsp;Clare Eglin ,&nbsp;Harvey Belcher ,&nbsp;Daniel D. Piccolo ,&nbsp;Michael Tipton ,&nbsp;Maria Perissiou ,&nbsp;Zoe L. Saynor ,&nbsp;Anthony I. Shepherd","doi":"10.1016/j.jtherbio.2024.104017","DOIUrl":"10.1016/j.jtherbio.2024.104017","url":null,"abstract":"<div><div>Type 2 diabetes mellitus (T2DM) is characterised by endothelial dysfunction, leading to increased risk of cardiovascular disease. Emerging evidence suggest that HWI may favourably improve vascular function but data are limited in individual with T2DM. The aim was to investigate whether repeated hot water immersion (HWI) improved macrovascular, microvascular and central haemodynamic function in individuals with T2DM.</div><div>Fourteen individuals completed a pre-post experimental study where participants were assessed pre- and post-8-10 × 1 h HWI sessions (40 °C water) undertaken within a 14-day period. During HWIs, body position was adjusted to clamp rectal temperature at 38.5–39.0 °C for the duration of the immersion. Stroke volume index (SVi), cardiac index (<span><math><mrow><mover><mi>Q</mi><mo>˙</mo></mover></mrow></math></span> i), resting heart rate (HR), systolic blood pressure (SBP), diastolic BP (DBP), brachial flow-mediated dilation (FMD) and cutaneous microvascular endothelial function (via transdermal iontophoresis) and plasma [nitrate] and [nitrite] (NOX; via ozone chemiluminescence) were assessed pre- and post HWI.</div><div>Neither brachial FMD measures of macrovascular endothelial function (<em>p</em> = 0.43) or forearm microvascular function (ACh max, <em>p</em> = 0.63; ACh area under curve (AUC), <em>p</em> = 0.63; insulin max, <em>p</em> = 0.51; insulin AUC, <em>p</em> = 0.86) or NOX (<em>p</em> = 0.38) were changed. <span><math><mrow><mover><mi>Q</mi><mo>˙</mo></mover></mrow></math></span> i (<em>p</em> &lt; 0.01), SVi (<em>p</em> &lt; 0.02) and resting HR (<em>p</em> &lt; 0.01) were all significantly reduced following the 10-days HWI intervention. SBP was reduced (<em>p</em> = 0.03), whereas DBP was unchanged (<em>p</em> = 0.56).</div><div>HWI may represent an appropriate intervention to improve <span><math><mrow><mover><mi>Q</mi><mo>˙</mo></mover></mrow></math></span> I, SVi and BP in individuals with T2DM, but not macrovascular endothelial or cutaneous microvascular function.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104017"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142791941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lack of agreement among analysers of infrared thermal images in the temperature of eye regions in sheep","authors":"María Leontina Bakker ,&nbsp;Guillermo Daniel Milano ,&nbsp;Jimena Fernández ,&nbsp;Patricia Inés Alvarado ,&nbsp;Laura Beatriz Nadin","doi":"10.1016/j.jtherbio.2024.104021","DOIUrl":"10.1016/j.jtherbio.2024.104021","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Infrared thermography (IRT) is a non-invasive method to estimate body temperature in many animal species. The eye has been indicated as the ideal region for IRT, potentially serving as an early indicator of variations in body temperature triggered by various events and stimuli. Studies are being conducted to understand sources of variation in IRT temperature of the eye and develop comprehensive guidelines for veterinary medicine and animal production purposes. The present study adds information about variation in temperature estimated from different eye regions in sheep due to analysers. Thirty-one thermal images, fifteen of the right and sixteen of the left eyes of a ewe, captured with a FLIR E8-XT camera, were analysed by each of three analysers, and minimum (Tmin), maximum (Tmax) and average (Tavg) temperature in lacrimal caruncle (&lt;strong&gt;R1&lt;/strong&gt;), medial canthus of the eye (&lt;strong&gt;R2&lt;/strong&gt;) and eyeball (&lt;strong&gt;R3&lt;/strong&gt;) were estimated. Differences among analysers were analysed by ANOVA (normal distribution) or Friedman test (non-normal distribution), considering thermal images as blocks. Limits of Agreement with the Mean (LOAM) were estimated and agreement plots were drawn. There were no differences (P &gt; 0.05) among analysers in temperature (°C, mean ± standard deviation or median and 2.5%–97.5% quantiles) estimated in &lt;strong&gt;R1&lt;/strong&gt; (Tmin = 36.3 ± 0.87, Tmax = 37.2 (35.9–37.7), Tavg = 36.7 ± 0.67), &lt;strong&gt;R2&lt;/strong&gt; (Tmax = 37.2 (36.0–37.8)) and &lt;strong&gt;R3&lt;/strong&gt; (Tavg = 36.1 (34.9–37.3)) for the right eye (n = 45), and in &lt;strong&gt;R1&lt;/strong&gt; (Tmin = 36.0 (34.3–37.3), Tmax = 36.8 ± 0.49, Tavg = 36.4 ± 0.53), &lt;strong&gt;R2&lt;/strong&gt; (Tmin = 35.9 ± 0.71&lt;strong&gt;,&lt;/strong&gt; Tmax = 36.7 (35.8–37.7), Tavg = 36.3 (35.5–37.5)) and &lt;strong&gt;R3&lt;/strong&gt; (Tavg = 35.9 (34.8–36.6)) for the left eye (n = 48); but differences (P &lt; 0.05) were present in &lt;strong&gt;R3&lt;/strong&gt; (Tmin, Tmax) for both eyes and in &lt;strong&gt;R2&lt;/strong&gt; (Tmin and Tavg) for the right eye. The highest mean differences in temperature (°C) (P &lt; 0.05) among analysers were in &lt;strong&gt;R3&lt;/strong&gt; from the right eye (Tmin = 0.70, Tmax = 0.25) and the left eye (Tmin = 0.64, Tmax = 0.10), and in &lt;strong&gt;R2&lt;/strong&gt; from the right eye (Tmin = 0.54, Tavg = 0.50). Considering both eyes and all eye regions, the total range for the LOAM (°C) was lower for Tmax (0.42–0.93) and Tavg (0.63–1.17) than for Tmin (1.49–2.70), indicating a higher, medium, and lower agreement among analysers for Tmax, Tavg and Tmin, respectively. Considering the eyes, the total range for the LOAM (°C) was lower in all regions from the left eye (0.42–1.59) compared to the right eye (0.79–2.70), indicating a higher agreement among analysers from the left eye. Considering the eye regions, the total range for the LOAM (°C) was generally higher in &lt;strong&gt;R3&lt;/strong&gt; (0.84–3.70) than in &lt;strong&gt;R1&lt;/strong&gt; (0.61–1.79) and &lt;strong&gt;R2&lt;/strong&gt; (0.42–2.03), indicating the lowest agreement among ana","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104021"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of a prototype ventilated vest in mitigating physiological and cognitive impairments during simulated military tasks in hot environments","authors":"Urša Ciuha ,&nbsp;Sara Podgornik ,&nbsp;Jason T. Fisher ,&nbsp;Boštjan Marolt ,&nbsp;Igor B. Mekjavic","doi":"10.1016/j.jtherbio.2024.104014","DOIUrl":"10.1016/j.jtherbio.2024.104014","url":null,"abstract":"<div><div>Many occupations, including military and industrial, cannot benefit from large-scale cooling strategies; therefore, personal cooling strategies may be more appropriate. We assessed the efficacy of a ventilated vest (Vest) based on participant’ autonomic and cognitive responses during military-related activities in the heat.</div><div>Male soldiers conducted 90-min trials in 35 °C ambient temperature and 40% relative humidity: i) March with/without Vest (N = 10), ii) Guard duty with/without Vest (N = 8). During each trial, we monitored their physiological (gastrointestinal temperature, T_gi; skin temperature, T_skin; torso microclimate temperature/humidity, M_T/M_RH; oxygen uptake, VO₂; Heart rate, HR) and cognitive (reaction time, number of errors) and subjective responses.</div><div>While some elements of T_gi, T_skin, M_T, and HR reduction in the Vest trial were observed, these decrements were small and persisted only for a short period of time. VO₂ was significantly affected by the exercise but unaffected by the Vest (with vs. without) (<em>p</em> &gt; 0.05). Cognitive performance did not improve significantly with the use of the Vest. However, reaction time improved after both trials. Sweat accumulation in the near-to-skin clothing layer was 2x (March) and 9x (Guard) higher (<em>p</em> &lt; 0.001) without the vest, and participants reported feeling more comfortable and cooler when wearing the vest.</div><div>The significantly lower sweat accumulation in the next-to-skin clothing layers when wearing the Vest improved thermal comfort and sensation, which was not reflected in the autonomic and cognitive response under the prevailing conditions. Possibly, a more powerful and upgraded concept of the vest could result in improved physiological and cognitive performance.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104014"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142801242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature alters antioxidant status and induces cell damage in the Amazonian fish tambaqui","authors":"Renan Diego Amanajás ,&nbsp;Jhonatan Mota da Silva ,&nbsp;Maria de Nazaré Paula da Silva ,&nbsp;Adalberto Luis Val","doi":"10.1016/j.jtherbio.2024.103995","DOIUrl":"10.1016/j.jtherbio.2024.103995","url":null,"abstract":"<div><div>Since Amazonian fish live close to their maximum thermal limits, this makes them vulnerable to the effects of global warming. The aim of this study was to evaluate the oxidative stress and antioxidant enzymatic and biochemical responses of the plasma, liver and muscle of tambaqui (<em>Colossoma macropomum</em>) exposed to a rising gradient of water temperature. One hundred and twenty (N = 120) juvenile tambaqui were exposed to four temperature levels, these being: the environmental temperature of the season (T_env – 25.7–30 °C), 31 °C, 34 °C and 37 °C, following a completely randomized design with three replicates for a period of 60 days. Liver and muscle samples were used to determine the levels of the enzymes superoxide dismutase (SOD), catalase (CAT) glutathione peroxidase (GPx) and lipid peroxidation (LPO). Plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. A histopathological damage assessment (HAI) was performed using liver samples and the results showed an increase in lipid peroxidation in the muscle and liver of animals kept at 37 °C in relation to other temperatures. Enzyme responses were tissue-specific in the liver and muscle. In the liver, the reduction of CAT, SOD and GPx levels of the animals was observed at 37 °C compared to those maintained at T_env and SOD and GPx in relation to animals maintained at 31 and 34 °C. The GPx enzyme showed higher activity at 34 and 37 °C compared to the other evaluated temperatures. At 37 °C, plasma levels of ALT and AST were higher than the other temperatures evaluated, as well as an increase in histopathological damage. In this way, in a scenario of warming of the waters of the Amazon or even of the systems used for rearing of the species, the tambaqui will be able to cope with temperatures of up to 34 °C, without affecting its antioxidant capacity. However, at 37 °C, oxidative stress levels and increased liver damage suggest a reduction in antioxidant capacity due to tissue impairment of the organ and general loss of animal performance as it approaches the upper thermal limit of the species.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 103995"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"mRNA expression of kidney aquaporins and blood composition of meat-type chickens raised with or without glucose supplementation under cyclic heat or thermoneutral condition","authors":"Oluwatomide W. Ariyo ,&nbsp;Josephine Kwakye ,&nbsp;Selorm Sovi ,&nbsp;Bikash Aryal ,&nbsp;Evan Hartono ,&nbsp;Ahmed F.A. Ghareeb ,&nbsp;Marie C. Milfort ,&nbsp;Alberta L. Fuller ,&nbsp;Romdhane Rekaya ,&nbsp;Samuel E. Aggrey","doi":"10.1016/j.jtherbio.2024.104003","DOIUrl":"10.1016/j.jtherbio.2024.104003","url":null,"abstract":"<div><div>Heat stress (HS) disrupts water homeostasis in broiler chickens. Kidney aquaporins (AQPs) facilitate water permeability in the renal tubules, thereby maintaining homeostasis of body water and metabolites. We evaluated the mRNA expression of kidney AQPs 1, 2, 3 and 4, and the blood composition of broilers raised under thermoneutral (TN) or cyclic HS condition with or without glucose supplementation. The treatments were TN+0% glucose (TN0), TN+6% glucose (TN6), HS+0% glucose (HS0), and HS+6% glucose (HS6). Each treatment had 6 replicates of 19 birds each. Groups with glucose (Glu) supplementation continuously received 6% Glu in water, and HS groups were exposed to a cyclic HS regime involving 35 °C from 8am to 8pm, and subsequently retuned to 25 °C (thermoneutral) from 8pm to 8am. Both heat and glucose supplementation were applied from d28 to d35. Blood and kidney were collected from 1 bird/replicate on d35. AQP-1, -2, and -3 were highly expressed (p &lt; 0.05) in HS0 relative to TN0, TN6, and HS6. Birds in the TN6 and HS6 had a lower expression of AQP2 while HS0 and HS6 had a lower expression of AQP4. Birds in the HS0 group had a higher water consumption relative to TN0, TN6 and HS6. HS0 and HS6 had a higher water conversion ratio relative to TN0 and TN6. Heat stress lowered (p &lt; 0.05) blood PCO₂, TCO_2, and HCO₃. The blood pH, Na, K, and Cl composition were not affected (p &gt; 0.05) with heat or glucose supplementation. Cyclic HS (p &lt; 0.0001) and glucose supplementation (p = 0.0090) raised the blood glucose level. Kidney aquaporins 1, 2, and 3 are important indicators of water utilization in HS broiler chickens.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104003"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142784691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerobic performance in rats subjected to incremental-speed running exercise: A multiple regression analysis study emphasizing thermoregulation-related variables","authors":"Marcelo T. Andrade ,&nbsp;Nicolas H.S. Barbosa ,&nbsp;Roberto C.S. Souza-Junior ,&nbsp;Cletiana G. Fonseca ,&nbsp;William C. Damasceno ,&nbsp;Kássya Regina-Oliveira ,&nbsp;Lucas R. Drummond ,&nbsp;Myla A. Bittencourt ,&nbsp;Ana C. Kunstetter ,&nbsp;Pedro V.R. Andrade ,&nbsp;Alexandre S.R. Hudson ,&nbsp;Thales N. Prímola-Gomes ,&nbsp;Francisco Teixeira-Coelho ,&nbsp;Cândido C. Coimbra ,&nbsp;Washington Pires ,&nbsp;Samuel P. Wanner","doi":"10.1016/j.jtherbio.2024.104016","DOIUrl":"10.1016/j.jtherbio.2024.104016","url":null,"abstract":"<div><div>Single-variable analyses have limited ability to explain complex phenomena such as the regulation of prolonged physical (aerobic) performance. Our study aimed to identify predictors of performance in rats subjected to incremental-speed running exercise. Notably, most variables assessed were associated with rats’ thermoregulation. We extracted data from 355 records obtained in 216 adult Wistar rats. Hierarchical multiple linear regression analyses were conducted to identify the predictive power of eight variables. The distance traveled, a performance index, was the dependent variable. The independent variables included body mass, biological sex, body core temperature (T_CORE) measurement site, and the following thermoregulation-related variables: ambient temperature (T_AMB), initial T_CORE, exercise-induced change in T_CORE (ΔT_CORE), ΔT_CORE from 0 to 10 min (ΔT_CORE 0–10; when T_CORE increase is fastest), and heat loss index (HLI). This analysis with eight variables revealed an adjusted R² of 0.495; T_AMB, ΔT_CORE, body mass, and ΔT_CORE 0–10 had the highest predictive powers (β values: −0.700, 0.463, −0.353, and −0.130, respectively). Additional analyses consisted of separate regressions for each T_CORE index measured: abdominal (T_ABD), brain (T_BRAIN), and colonic (T_COL) temperature. These analyses yielded adjusted R² values of 0.608 (T_ABD), 0.550 (T_BRAIN), and 0.437 (T_COL). Again, the distance traveled was primarily predicted by body mass and thermoregulation-related variables (T_AMB, ΔT_CORE, and ΔT_CORE 0–10). Among these four variables, ΔT_CORE was the only one with a positive β value (directly predicted performance), while the others had negative values. Collectively, these findings advance our understanding of performance regulation in rats, especially regarding the role of thermoregulation-related variables.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104016"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142800964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Body size influences the capacity to cope with extreme cold or hot temperatures in the striped hamster","authors":"Chenxiao Hu,&nbsp;Ruihan Zhang,&nbsp;Wenting Zhang,&nbsp;Yuxin Zheng,&nbsp;Jing Cao,&nbsp;Zhijun Zhao","doi":"10.1016/j.jtherbio.2024.104008","DOIUrl":"10.1016/j.jtherbio.2024.104008","url":null,"abstract":"<div><div>Body size of organisms is a key trait influencing nearly all aspects of their life history. Despite growing evidence of Bergmann's rule, there is considerably less known about the links between body size and the maximum capacity to thermoregulate of an animal in response to extreme cold or hot environment. Thermal characteristics such as resting metabolic rate (RMR) and non-shivering thermogenesis (NST), and the upper- and lower-critical temperatures of the thermal neutral zone (TNZ) were investigated in small and large body sized striped hamsters (<em>Cricetulus barabensis</em>). The maximum capacity to thermoregulate in response to extreme cold (−15 °C) or hot temperature (38 °C) was also examined, where both, different sized hamsters had similar RMR and NST regardless of temperature exposure. The large hamsters had 29.9% more body mass compared to small hamsters. The large hamsters showed a wider TNZ, with lower, lower-critical temperature, and showed considerable hyperthermia at the end of a 17-h hot exposure. In contrast, the small hamsters showed hypothermia following a 17-h cold exposure relative to large hamsters. In addition, the large hamsters showed 17.2% lower basal thermal conductance, and 14.9% lower maximum thermal conductance than the small hamsters after cold exposure, and 22.6% lower thermal conductance following heat exposure. Several molecular markers indicative of thermogenesis and oxidative stress did not differ significantly between the large and small hamsters. These findings suggest that individuals with larger body sizes have greater capacity to thermoregulate to cope with extreme cold, and a reduced capacity in response to extreme hot. In contrast, smaller individuals demonstrated the opposite trend. Body size may decide the capacity to thermoregulate to cope with extreme cold and heat, within which body heat dissipation is likely more important than heat production.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104008"},"PeriodicalIF":2.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142785986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age and mating status have complex but modest effects on the critical thermal limits of adult Mediterranean fruit flies from geographically divergent populations","authors":"Antonis G. Papadopoulos ,&nbsp;Panagiota Koskinioti ,&nbsp;Kostas D. Zarpas ,&nbsp;Paraschos Prekas ,&nbsp;John S. Terblanche ,&nbsp;Daniel A. Hahn ,&nbsp;Nikos T. Papadopoulos","doi":"10.1016/j.jtherbio.2024.104013","DOIUrl":"10.1016/j.jtherbio.2024.104013","url":null,"abstract":"<div><div>The highly invasive Mediterranean fruit fly (medfly), <em>Ceratitis capitata</em> (Wiedemann) (Diptera: Tephritidae), is currently expanding its geographic distribution into cooler temperate areas of the Northern Hemisphere. In marginal conditions, the invasion potential of medfly depends in part on innate tolerance to the novel environmental conditions. Physiological tolerances are potentially influenced by interactions among multiple factors, such as organism age or reproductive maturity, sex, and mating status. Furthermore, the relationships between the above factors and tolerances may differ among geographically distinct populations. Here, the effects of age and mating status on thermal tolerance of three geographically distinct medfly populations along a latitudinal gradient ranging from Greece (Crete &amp; Volos) to Croatia (Dubrovnik) were examined. The upper and lower critical thermal limits (scored as loss of neuromuscular function during controlled cooling or heating) of adult males and females (a) at 1-, 6-, 15-, and 35 days old and of (b) both mated and virgin flies were assessed. Results showed that estimates of lower and upper thermal limits (CTmin and CTmax) were both population- and age-dependent. In most age classes tested, CTmin values were lower for the adults obtained from Crete and higher for those from Dubrovnik. CTmax values were lower for the females from Dubrovnik compared to the females from any other population on day one after emergence but not on days 6, 15 and 35. Differences among populations were observed across different age classes both for cold and heat tolerance but mostly in CTmin estimates. Mating status had a little effect on cold and heat tolerance. Complex patterns of thermal limit variation within and among populations suggest a suite of factors determine population-level mortality from thermal extremes under field conditions in medfly. These results contribute towards understanding the invasion dynamics of medfly and its range expansion to northern, more temperate regions of Europe.</div></div>","PeriodicalId":17428,"journal":{"name":"Journal of thermal biology","volume":"126 ","pages":"Article 104013"},"PeriodicalIF":2.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142716505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}