Control Heat Stress Research Articles

Translation Efficiency Test Using Polysome Profiles Under Heat Stress.

Translational control of different genes under heat stress is a critical step for plant adaptation to the environment. Assessing the translational activities of various genes can help us understand the molecular mechanisms underlying plant resilience, contributing to the development of crops with enhanced stress tolerance in the face of global climate change. This paper presents a detailed methodology for assessing translation efficiency through polysome profiling in plants exposed to heat stress. The procedure is divided into three parts: heat stress treatment for Arabidopsis, translation efficiency test using polysome profiles, and calculation of translation efficiency by isolating non-polysomal and polysomal RNA based on the profile. In the first part, Arabidopsis plants are subjected to controlled heat stress conditions to mimic environmental challenges. The treatment involves exposing the plants to high temperatures for specified durations, ensuring consistent and reproducible stress induction. This step is crucial for studying the plant's physiological and molecular responses to heat stress. The second part involves the translation efficiency test using polysome profiling. Polysomes are extracted through sucrose gradient centrifugation, which separates mRNAs based on ribosomal loading. This allows for the examination of ribosome occupancy on mRNAs, providing insights into the translational control mechanisms under stress conditions. In the third part, RNA is isolated from both polysomal and non-polysomal fractions. Spike-in RNA is used to accurately measure the amount of RNA in each fraction. The calculation of translation efficiency is performed by comparing the distribution of mRNAs across these fractions under normal and heat stress conditions. The translation activities of specific genes are further assessed by performing quantitative real-time PCR (qRT-PCR) with ribosome-associated RNA and total RNA. This methodology focuses exclusively on the effects of heat stress, providing a detailed protocol for analyzing translational regulation in plants.

Inheritance Analysis for Quantitative Traits in F2 Populations of Mustard Genotypes Grown Under Heat Stress Environments

Genetic variability is the basic requirement for improving crops which further leads to progress in crop breeding. This study was carried out to determine the inheritance pattern of various agronomically important traits in F2 populations of mustard genotypes. The objective of this study was to determine the genetic variability for agro-morphological traits under control conditions (CC) and heat stress environments (HS) and provide the future strategies to improve this important oilseed crop. The experiment was conducted at the Botanical Garden, Sindh Agriculture University, Tandojam. During 2022-23, a total of 27 genotypes including nine parental mustard genotypes and eighteen F2 progenies were grown under control and heat stress conditions. The experiment was laid out in a randomized complete block design with three replications. The analysis of variance for the genotypes, treatments, and F2 progenies revealed significant differences (P≤0.05) in most of the studied characters, highlighting the importance of genetic variations in the evaluated breeding materials of mustard for stress breeding. When estimating heritability for different characters, including seed yield plant-1, it was found that F2 crosses showed varying levels of heritability for different characteristics, ranging from low to moderate and high. This implies that careful selection may be conducted for traits that have low heritability, especially for seed yield.; however, those characters which showed high heritability would be selected at early generation stage to improve the characters.

Prehatch thermal manipulation of embryos and posthatch baicalein supplementation increased liver metabolism, and muscle proliferation in broiler chickens

The exposure of broiler chickens to high ambient temperatures causes heat stress (HS), negatively affecting their health and production performance. To mitigate heat stress in broilers, various strategies, including dietary, managerial, and genetic interventions, have been extensively tested with varying degrees of efficacy. For sustainable broiler production, it is imperative to develop an innovative approach that effectively mitigates the adverse effects of HS. Our previous studies have provided valuable insights into the effects of prehatch embryonic thermal manipulation (TM) and posthatch baicalein supplementation on embryonic thermotolerance, metabolism, and posthatch growth performance. This follow-up study investigated the effect of these interventions on gluconeogenesis and lipid metabolism in the liver, as well as muscle proliferation and regeneration capacity in heat-stressed broiler chickens. A total of six-hundred fertile Cobb 500 eggs were incubated for 21 d. After candling, 238 eggs were subjected to TM at 38.5°C with 55% relative humidity (RH) from embryonic day (ED) 12 to 18. These eggs were transferred to the hatcher and kept at a standard temperature (37.5°C) from ED 19 to 21, while 236 eggs were incubated at a controlled temperature (37.5°C) till hatch. After hatching, 180 day-old chicks from both groups were raised in 36 pens treatment (n = 10 birds/pen, 6 replicates per treatment). The treatments were: 1) Control, 2) TM, 3) Control heat stress (CHS), 4) Thermal manipulation heat stress (TMHS), 5) Control heat stress supplement (CHSS), and 6) Thermal manipulation heat stress supplement (TMHSS). Baicalein was added to the treatment group diets starting from d 1. All birds were raised under the standard environment for 21 d, followed by chronic heat stress from d 22 to 35 (32-33 ⁰C for 8 h) in the CHS, TMHS, CHSS, and TMHSS groups. A thermoneutral (22-24⁰C) environment was maintained in the Control and TM groups. RH was constant (50 ± 5%) throughout the trial. In the liver, TM significantly increased (P < 0.05) IGF2 expression. Baicalein supplementation significantly increased (P < 0.05) HSF3, HSP70, SOD1, SOD2, TXN, PRARα, and GHR expression. Moreover, the combination of TM and baicalein supplementation significantly increased (P < 0.05) the expression of HSPH1, HSPB1, HSP90, LPL, and GHR. In the muscle, TM significantly increased (P < 0.05) HSF3 and Myf5 gene expression. TM and baicalein supplementation significantly increased (P < 0.05) the expression of MyoG and significantly (P < 0.05) decreased mTOR and PAX7. In conclusion, the prehatch TM of embryos and posthatch baicalein supplementation mitigated the deleterious effects of HS on broiler chickens by upregulating genes related to liver gluconeogenesis, lipid metabolism, and muscle proliferation.

New population of Solanum pimpinellifolium backcross inbred lines as a resource for heat stress tolerance in tomato.

The occurring temperature increase in crop production areas worldwide is generating conditions of heat stress that negatively affect crop productivity. Tomato (Solanum lycopersicum), a major vegetable crop, is highly susceptible to elevated temperatures. Under such conditions, fruit set is dramatically reduced, leading to significant yield losses. Solanum pimpinellifolium, a wild species closely related to the cultivated tomato, was shown to have beneficial attributes under various abiotic stress growth conditions. We have utilized a new population of backcross inbred lines originated from a cross between S. pimpinellifolium and S. lycopersicum, in order to evaluate its potential as a new genetic resource for improvement of reproductive performance of cultivated tomato under heat stress conditions. This population was screened for various heat stress-related traits, under controlled heat stress and non-stress conditions. Our results show that significant variation exists for all the heat stress related traits that were examined and point at individual lines with better reproductive performance under heat stress conditions that share a common introgression from the wild S. pimpinellifolium parent, suggesting several candidate genes as potential drivers of thermotolerance. Thus, our results place this population as a valuable new resource for the discovery of heat stress related genetic loci for the future development of heat stress tolerant tomato cultivars.

A Study on the Effect of Housing on Physiological Responses of Nellore Lambs Kasala

A study was carried out to find out the effect of housing on physiological responses of Nellore Jodipi lambs under tropical environmental conditions. Thirty weaned Nellore ram lambs of 3-4 months age were selected based on body weight (average initial body weight) and randomly divided into three groups of ten animals each. The lambs in Group-I were housed with morum flooring and asbestos roofing with tree shade, while Group-II lambs were housed with morum flooring and asbestos roofing without tree shade and Group-III lambs were housed with elevated slatted flooring and galvalume roofing without tree shade. Temperature and humidity values were significantly (P&lt;0.05) different among all the groups. Lower mean maximum temperature (°C) values were observed in group III (35.53±0.28) when compared to group I (36.22±0.27) and II (37.29±0.25) and the lower average maximum relative humidity (%) was 69.59±2.92 in group III followed by group II (69.88±2.94) and I (70.65±2.96). The mean physiological responses viz., rectal temperature, respiration rate and pulse rate were significantly (P&lt;0.05) lower in group III (102.38±1.00°F, 26.25±1.00bpm, 69.07±1.00beats/min.) when compared to group I (102.60±1.00°F, 31.60±1.00bpm, 82.10±1.00beats/min.) and II (102.85±1.00°F, 33.56±1.00bpm, 87.08±1.00beats/min.), respectively. It was concluded that the housing system of elevated slatted flooring with galvalume roofing proved to be effective in controlling heat stress and maintaining normal physiological responses for better growth performance of Nellore ram lambs.

A Study on the Effect of Housing on Serum Biochemical Parameters of Nellore Lambs

A study was carried out to find out the effect of housing on serum biochemical parameters of Nellore Jodipi lambs under tropical environmental conditions. Thirty weaned Nellore ram lambs of 3-4 months age were selected based on body weight and randomly divided into three groups of ten animals each. Temperature and humidity values were significantly (P&lt;0.05) different among all the groups. The mean serum biochemical parameters like creatinine, urea, sodium, potassium, calcium, ALT and AST were significantly (P&lt;0.05) higher in group II (1.75±1.00 mg/dl, 21.23±1.00 mg/dl, 150.16±1.00 mmol/L, 4.76±0.22 mmol/L, 12.87±1.00 mg/dl, 243.38±1.00 IU/L, 32.03±1.00I U/L) when compared to group I (1.36±1.00 mg/dl, 13.71±1.00 mg/dl, 144.95±1.0 mmol/L, 4.55±0.22 mmol/L, 12.06±1.00 mg/dl, 171.77±1.00 IU/L, 26.93±1.00 IU/L) and group III (1.32±1.00 mg/dl, 8.96±1.00 mg/dl, 141.77±1.00 mmol/L, 3.99±1.00 mmol/L, 11.27±1.00 mg/dl, 124.53±1.00 IU/L, 23.88±1.00 IU/L) respectively, whereas, other parameters like glucose was significantly (P&lt;0.05) lower in group II (39.07±1.00 mg/dl) when compared to group I (55.41±1.00 mg/dl) and III (75.26±1.00 mg/dl). It was concluded that the housing system of elevated slatted flooring with galvalume roofing proved to be effective in controlling heat stress and maintaining normal serum biochemical parameters of Nellore ram lambs.

The Impacts of Heat Stress on Rumination, Drinking, and Locomotory Behavior, as Registered by Innovative Technologies, and Acid-Base Balance in Fresh Multiparous Dairy Cows.

This study hypothesizes that heat stress adversely affects dairy cows, resulting in reduced rumination, altering eating and drinking behaviors, changes in their locomotory patterns, and significant variations in their acid-base balance. The aim of this study was to investigate the impacts of heat stress on rumination, drinking, and locomotory behavior, as registered by innovative technologies, and acid-base balance in fresh multiparous dairy cows. This study was conducted during the summer, from 15 June to 8 July 2023, on a Lithuanian commercial dairy farm. We assessed 350 German Holstein cows that produced an average of 11,400 kg of milk annually throughout their second and subsequent lactation periods. We used the temperature-humidity index (THI) to divide the cows under investigation into three periods: I. high HS-THI >78 (period: 15-23 June 2023); II. medium HS-THI 72-78 (period: 24-30 June 2023); and III. low HS-THI <72 (period: 1-8 July 2023). The appropriate RumiWatch sensor (RWS) parameters were assessed between 15 June 2023 and 8 July 2023. Cows were acclimatized to the rumination, drinking, and locomotory behavior parameters during the adaptation period (1-30 June 2023). The registration process started on 15 June 2023 and terminated on 8 July 2023 and was performed every hour during the 24 h day. The acid-base balance was recorded from 15 June 2023 until 8 July 2023, once per week. The cows' activity increased by 11.75% in the high HS period compared to the low HS period (p < 0.01); high mean differences were detected for rumination, which was 17.67% higher in the high HS period and 13.80% higher in the medium HS period compared to the low HS period (p < 0.01); and the change in activity was 12.82% higher in the low HS compared to the medium HS period (p < 0.01). Cows under high HS had higher blood urea nitrogen (BUN) levels compared with cows under medium HS (p < 0.01). The observed alterations in the rumination, drinking, and locomotory behaviors, in addition to the acid-base balance, highlight the multifaceted impacts of varying heat stress on the physiological and behavioral responses of dairy cows. This suggests that the utilization of advanced technologies may assist dairy farmers in effectively monitoring and controlling heat stress in cows. Additionally, regularly assessing blood urea nitrogen levels can enable farmers to modify their feeding practices, thus promoting optimal cow well-being and productivity.

Host starvation and in hospite degradation of algal symbionts shape the heat stress response of the Cassiopea-Symbiodiniaceae symbiosis

BackgroundGlobal warming is causing large-scale disruption of cnidarian-Symbiodiniaceae symbioses fundamental to major marine ecosystems, such as coral reefs. However, the mechanisms by which heat stress perturbs these symbiotic partnerships remain poorly understood. In this context, the upside-down jellyfish Cassiopea has emerged as a powerful experimental model system.ResultsWe combined a controlled heat stress experiment with isotope labeling and correlative SEM-NanoSIMS imaging to show that host starvation is a central component in the chain of events that ultimately leads to the collapse of the Cassiopea holobiont. Heat stress caused an increase in catabolic activity and a depletion of carbon reserves in the unfed host, concurrent with a reduction in the supply of photosynthates from its algal symbionts. This state of host starvation was accompanied by pronounced in hospite degradation of algal symbionts, which may be a distinct feature of the heat stress response of Cassiopea. Interestingly, this loss of symbionts by degradation was concealed by body shrinkage of the starving animals, resulting in what could be referred to as “invisible” bleaching.ConclusionsOverall, our study highlights the importance of the nutritional status in the heat stress response of the Cassiopea holobiont. Compared with other symbiotic cnidarians, the large mesoglea of Cassiopea, with its structural sugar and protein content, may constitute an energy reservoir capable of delaying starvation. It seems plausible that this anatomical feature at least partly contributes to the relatively high stress tolerance of these animals in rapidly warming oceans.7jQYTVpxtJyVhU5epTFb61Video

Transcriptional modulation of heat shock proteins and adipogenic regulators in bovine adipocytes following heat exposure

This research endeavored to elucidate the transcriptional modulation of heat shock proteins and adipogenic regulators in bovine subcutaneous adipocytes following thermal exposure. Post-differentiation, mature adipocytes were subjected to three treatments of control (CON), moderate (MHS), and extreme (EHS) heat stress. These treatments consist of thermal conditions at temperatures of 38 °C (CON), 39.5 °C (MHS), or 41 °C (EHS) along with of 3 or 12 h. There was no statistically significant variations observed in the gene expressions of HSP27 and HSP70 when comparing CON with MHS across both exposures. Contrastingly, when comparing CON with EHS, an upregulation (P < 0.01) in HSP27 gene expression was evident for both 3 and 12 h of incubation, while HSP70 gene expression exhibited elevation (P < 0.01) at the 3-h mark, with no change observed at 12 h. Protein quantification, however, revealed an elevation (P < 0.01) in HSP27 and HSP70 for both CON vs. MHS and CON vs. EHS at the 12-h exposure. This trend in protein level mirrored (P < 0.05) that of proliferator-activated receptor-gamma (PPARγ). Elevated (P < 0.05) protein levels of fatty acid synthase (FAS) were exclusively discernible in the CON vs. MHS. Increased (P < 0.01) transcriptional activity of PPARγ, CCAAT/enhancer-binding protein alpha (C/EBPα), stearoyl-CoA desaturase (SCD), and FAS was evident in the CON vs. EHS comparison. Complementary to these molecular findings, an augmented lipid droplet accumulation was observed (P < 0.01) in EHS-exposed adipocytes progressively from day 6 through day 9. Our current study highlights how different levels and lengths of heat stress can impact the activity of important heat-related proteins and factors that play a role in fat development in beef cattle. These findings can help guide strategies to manage how beef cattle are exposed to heat, which can affect fat storage and ultimately the quality of the meat's marbling.

Pre-hatch thermal manipulation of embryos and post-hatch baicalein supplementation mitigated heat stress in broiler chickens

BackgroundHigh environmental temperatures induce heat stress in broiler chickens, affecting their health and production performance. Several dietary, managerial, and genetics strategies have been tested with some success in mitigating heat stress (HS) in broilers. Developing novel HS mitigation strategies for sustaining broiler production is critically needed. This study investigated the effects of pre-hatch thermal manipulation (TM) and post-hatch baicalein supplementation on growth performance and health parameters in heat-stressed broilers.ResultsSix hundred fertile Cobb 500 eggs were incubated for 21 d. After candling on embryonic day (ED) 10, 238 eggs were thermally manipulated at 38.5 °C with 55% relative humidity (RH) from ED 12 to 18, then transferred to the hatcher (ED 19 to 21, standard temperature) and 236 eggs were incubated at a controlled temperature (37.5 °C) till hatch. After hatch, 180-day-old chicks from both groups were raised in 36 pens (n = 10 birds/pen, 6 replicates per treatment). The treatments were: 1) Control, 2) TM, 3) control heat stress (CHS), 4) thermal manipulation heat stress (TMHS), 5) control heat stress supplement (CHSS), and 6) thermal manipulation heat stress supplement (TMHSS). All birds were raised under the standard environment for 21 d, followed by chronic heat stress from d 22 to 35 (32–33 °C for 8 h) in the CHS, TMHS, CHSS, and TMHSS groups. A thermoneutral (22–24 °C) environment was maintained in the Control and TM groups. RH was constant (50% ± 5%) throughout the trial. All the data were analyzed using one-way ANOVA in R and GraphPad software at P < 0.05 and are presented as mean ± SEM. Heat stress significantly decreased (P < 0.05) the final body weight and ADG in CHS and TMHS groups compared to the other groups. Embryonic TM significantly increased (P < 0.05) the expression of heat shock protein-related genes (HSP70, HSP90, and HSPH1) and antioxidant-related genes (GPX1 and TXN). TMHS birds showed a significant increment (P < 0.05) in total cecal volatile fatty acid (VFA) concentration compared to the CHS birds. The cecal microbial analysis showed significant enrichment (P < 0.05) in alpha and beta diversity and Coprococcus in the TMHSS group.ConclusionsPre-hatch TM and post-hatch baicalein supplementation in heat-stressed birds mitigate the detrimental effects of heat stress on chickens' growth performance, upregulate favorable gene expression, increase VFA production, and promote gut health by increasing beneficial microbial communities.

A Study on the Effect of Housing on Haematological Parameters of Nellore Lambs

A study was carried out to find out the effect of housing on haematological parameters of Nellore Jodipi lambs. Thirty weaned Nellore ram lambs of 3-4 months age were divided into three groups of ten each. The lambs in Group-I were housed with morum flooring and asbestos roofing with tree shade, while Group-II lambs were housed with morum flooring and asbestos roofing without tree shade and Group-III lambs were housed with elevated slatted flooring and galvalume roofing without tree shade. Temperature and humidity values were significantly (P&lt;0.05) different among all the groups. Lower mean maximum temperature (°C) values were observed in group III (35.53±0.28) when compared to group I (36.22±0.27) and II (37.29±0.25) and the lower average maximum relative humidity (%) was 69.59±2.92 in group III followed by group II (69.88±2.94) and I (70.65±2.96). The mean haematological parameters like RBC, WBC, Hb, PCV were significantly (P&lt;0.05) lower in group III (8.22±1.00×106/μl, 6.99±1.00×103/μl, 10.22±0.08 g/dl, 28.23±1.00 %) when compared to group I (9.66±1.00×106/μl, 9.01±1.00×103/μl, 10.85±0.08 g/dl, 31.27±1.00 %) and II (11.96±1.00×106/μl, 11.73±1.00×103/μl, 13.64±1.00 g/dl, 37.27±1.00%), respectively, whereas, other parameters like MCH, MCV, MCHC are significantly (P&lt;0.05) higher in group III (11.52±1.00 pg, 34.92±1.00 fl, 36.57±1.00 g/dl) when compared to group I (10.23±1.00 pg, 31.85±1.00 fl, 34.02±1.00 g/dl) and II (8.92±1.00 pg, 28.05±1.00 fl, 32.15±1.00 g/dl), respectively. It was concluded that the housing system of elevated slatted flooring with galvalume roofing proved to be effective in controlling heat stress and maintaining normal hematological parameters for better growth performance of Nellore ram lambs..

A Study on the Effect of Housing on Growth Performance of Nellore Lambs

A study was carried out to find out the effect of housing on growth performance of Nellore Jodipi lambs under tropical environmental conditions. Thirty weaned Nellore ram lambs of 3-4 months age were selected based on body weight (average initial body weight) and randomly divided into three groups of ten animals each. The lambs in Group-I were housed with morum flooring and asbestos roofing with tree shade, while Group-II lambs were housed with morum flooring and asbestos roofing without tree shade and Group-III lambs were housed with elevated slatted flooring and galvalume roofing without tree shade. Temperature and humidity values were significantly (P&lt;0.05) different among all the groups. Lower mean maximum temperature (°C) values were observed in group III (35.53±0.28) when compared to group I (36.22±0.27) and II (37.29±0.25) and the lower average maximum relative humidity (%) was 69.59±2.92 in group III followed by group II (69.88±2.94) and I (70.65±2.96). The average body weight of lambs after 120 days in group I, II and III was 19.92±0.52, 18.89±0.32 and 22.26±0.44 kg, respectively. The mean ADG of Nellore lambs at different weekly intervals was 31.0±1.00, 23.0±1.00 and 49.0±1.00 g in group I, II and III, respectively. Significant (P&lt;0.05) differences were observed in body weights and ADG among the three groups. It was concluded that the housing system of elevated slatted flooring with galvalume roofing proved to be effective in controlling heat stress and maintaining normal physiological responses for better growth performance of Nellore ram lambs.

Genetic variability, correlation and path analysis of yield and yield contributing characters in wheat (Triticum aestivum L.) under normal and terminal heat stress condition

Genetic variability and characters association studies play a pivotal role in enhancing selection efficiency under stress condition in plants. Therefore, the study was aimed at assessing the impact of terminal heat stress on various morpho-physiological traits and their association in wheat under control and terminal heat stress condition. The experiment was conducted using thirty-five wheat genotypes in a Randomized Complete Block design (RCBD) plots on three different sowing dates to induce terminal heat stress. A range of 11 morpho-physiological parameters were assessed. All of the traits showed significant variations under studied conditions. Estimates of the genotypic and phenotypic coefficients of variation (GCV and PCV) showed that PCV was higher than GCV indicating large environmental influence on the expression of the traits under study. High GCV and PCV were observed in grain per plant and yield per plant in both normal and heat stress conditions. Chlorophyll content, grain per plant and yield per plant showed highest heritability with high genetic advance (GA) under both normal and terminal heat stress condition. According to the results of the path co-efficient analysis, grain per plant had a strong positive connection with grain yield and plant height and days to 50% flowering had a negative correlation with grain yield per plant under both normal and stress condition. Canopy temperature has direct negative effect on yield in stress condition. The identified traits can be used as effective selection criteria under terminal heat stress condition to develop high yielding heat tolerant wheat variety.

Analisis Heat Strain Pada Pekerja Pembangunan Kapal PT.IKI (Persero) Makassar

Heat strain is the body's physiological response to heat stress received by a person. This research is a type of quantitative research with a cross-sectional study approach. The sampling technique in this study was random sampling with a total sample of 80 respondents. They are collecting data using questionnaires and interviews. Methods of data analysis using univariate and bivariate analysis with Chi-square test at 95% confidence level (p=0.05). The results showed a significant relationship between drinking water consumption and the heat strain factor (p=0.001); there was no relationship between the length of work and the heat strain factor (p=0.455) for workers in the production division at PT. IKI (Persero) 2023. It can be concluded that there is a relationship between the variable consumption of drinking water and the heat strain factor, and there is no relationship between the length of work and the heat strain factor in workers in the production division of PT. IKI (Persero). Suggested: There is a need for special attention from the agency on the importance of controlling heat stress to reduce the risk of occupational diseases in production workers at PT. IKI (Persero).

Measuring Heat Stress for Human Health in Cities: A Low-Cost Prototype Tested in a District of Valencia, Spain.

Nowadays, the measurement of heat stress indices is of principal importance due to the escalating impact of global warming. As temperatures continue to rise, the well-being and health of individuals are increasingly at risk, which can lead to a detrimental effect on human performance and behavior. Hence, monitoring and assessing heat stress indices have become necessary for ensuring the safety and comfort of individuals. Thermal comfort indices, such as wet-bulb globe temperature (WBGT), Tropical Summer Index (TSI), and Predicted Heat Strain (PHS), as well as parameters like mean radiant temperature (MRT), are typically used for assessing and controlling heat stress conditions in working and urban environments. Therefore, measurement and monitoring of these parameters should be obtained for any environment in which people are constantly exposed. Modern cities collect and publish this relevant information following the Smart City concept. To monitor large cities, cost-effective solutions must be developed. This work presents the results of a Heat Stress Monitoring (HSM) system prototype network tested in the Benicalap-Ciutat Fallera district in Valencia, Spain. The scope of this work is to design, commission, and test a low-cost prototype that is able to measure heat stress indices. The Heat Stress Monitoring system comprises a central unit or receiver and several transmitters communicating via radiofrequency. The transmitter accurately measures wind speed, air temperature, relative humidity, atmospheric pressure, solar irradiation, and black globe temperature. The receiver has a 4G modem that sends the data to an SQL database in the cloud. The devices were tested over one year, showing that radio data transmission is reliable up to 700 m from the receiver. The system's power supply, composed of a Photovoltaic panel and Lithium-ion batteries, provided off-grid capabilities to the transmitter, with a tested backup autonomy of up to 36 days per charge. Then, indicators such as WBGT, TSI, and MRT were successfully estimated using the data collected by the devices. The material cost of a 12-point network is around EUR 2430 with a competitive price of EUR 190 per device.

PSVIII-A-8 Growth and Physiological Responses to Heat Stress and Zilpaterol Hydrochloride in Angus and Brahman Steers

Abstract The response to zilpaterol hydrochloride supplementation by two breeds of beef steers under controlled heat stress conditions were evaluated for impacts on growth, carcass merit, and physiological stress indicators. In two separate studies, Brahman and Angus steers were placed in environmental chambers and housed for 21 d under 1 of 2 environmental conditions 1) heat stress (THI = 73 to 85) or thermoneutral (THI = 68). In a 2 x 2 factorial, steers also received 8.38 mg· kg-1· d-1 on 88% DM of zilpaterol hydrochloride (ZH) or soybean meal carrier only for the 21-d period. Feed intake, respiratory rate, and rectal temperatures were evaluated daily. Total weight gain was recorded and used to calculate average daily gain (ADG) and gain-to-feed ratio (G:F). Brahman steers were harvested at the market weight (489.31 ± 97.7 kg) and Angus steers on d ~22 after treatment (307.26 ± 6.23 kg). In both studies, body weight gain and ADG did not differ between environments or supplements. Brahman steers exposed to heat stress exhibited greater (P &amp;lt; 0.05) respiratory rate than thermoneutral steers, regardless of supplement. An environment x day interactions (P &amp;lt; 0.04) was observed for rectal temperature. On d 8, unsupplemented heat-stressed Brahman steers had higher (P &amp;lt; 0.05) rectal temperatures than ZH-supplemented thermoneutral steers. On d 11, ZH-supplemented heat-stressed Brahman steers had higher (P &amp;lt; 0.05) rectal temperatures than unsupplemented thermoneutral steers. Angus steers exposed to heat stress exhibited greater (P &amp;lt; 0.05) respiration rates throughout the experiment than thermoneutral steers. On d 8, unsupplemented heat-stressed Angus steers exhibited greater (P &amp;lt; 0.05) respiration rates than ZH-supplemented heat-stressed steers. On d 8 and 19, heat-stressed Angus steers exhibited greater (P &amp;lt; 0.05) rectal temperatures than thermoneutral steers. Angus steers exhibited an environment x supplement x day interaction (P &amp;lt; 0.05) for rectal temperature, with a decrease (P &amp;lt; 0.05) rectal temperature in ZH-supplemented steers. Carcass merit traits did not differ between environments in Brahman steers. Cold carcass weights were lighter (P &amp;lt; 0.05) in heat-stressed Angus steers compared with thermoneutral steers. ZH-supplemented Angus (but not Brahman) steers exhibited decreased (P &amp;lt; 0.05) respiration rates and rectal temperatures. Together these findings indicate that Brahman steers were more resistant to heat stress than Angus steers but were less efficient, with ~10% less G:F. Based upon the data collected, supplementation with zilpaterol hydrochloride did not negatively impact production in either breed.

Neuromuscular and gene signaling responses to passive whole-body heat stress in young adults

This study aimed to investigate whether acute passive heat stress 1) decreases muscle Maximal Voluntary Contraction (MVC); 2) increases peripheral muscle fatigue; 3) increases spinal cord excitability, and 4) increases key skeletal muscle gene signaling pathways in skeletal muscle. Examining the biological and physiological markers underlying passive heat stress will assist us in understanding the potential therapeutic benefits. MVCs, muscle fatigue, spinal cord excitability, and gene signaling were examined after control or whole body heat stress in an environmental chamber (heat; 82 °C, 10% humidity for 30 min). Heart Rate (HR), an indicator of stress response, was correlated to muscle fatigue in the heat group (R = 0.59; p < 0.05) but was not correlated to MVC, twitch potentiation, and H reflex suppression. Sixty-one genes were differentially expressed after heat (41 genes >1.5-fold induced; 20 < 0.667 fold repressed). A strong correlation emerged between the session type (control or heat) and principal components (PC1) (R = 0.82; p < 0.005). Cell Signal Transduction, Metabolism, Gene Expression and Transcription, Immune System, DNA Repair, and Metabolism of Proteins were pathway domains with the largest number of genes regulated after acute whole body heat stress. Acute whole-body heat stress may offer a physiological stimulus for people with a limited capacity to exercise.

Maintaining beneficial alga-associated bacterial communities under heat stress: insights from controlled co-culture experiments using antibiotic-resistant bacterial strains.

Brown algae, like many eukaryotes, possess diverse microbial communities. Ectocarpus-a model brown alga-relies on these communities for essential processes, such as growth development. Controlled laboratory systems are needed for functional studies of these algal-bacterial interactions. We selected bacterial strains based on their metabolic networks to provide optimal completion of the algal metabolism, rendered them resistant to two antibiotics, and inoculate them to establish controlled co-cultures with Ectocarpus under continuous antibiotic treatment. We then monitored the stability of the resulting associations under control conditions and heat stress using 16S metabarcoding. Antibiotics strongly reduced bacterial diversity both in terms of taxonomy and predicted metabolic functions. In the inoculated sample, 63%-69% of reads corresponded to the inoculated strains, and the communities remained stable during temperature stress. They also partially restored the predicted metabolic functions of the natural community. Overall, the development of antibiotic-resistant helper cultures offers a promising route to fully controlled laboratory experiments with algae and microbiota and thus represents an important step towards generating experimental evidence for specific host-microbe interactions in the systems studied. Further work will be required to achieve full control and progressively expand our repertoire of helper strains including those currently 'unculturable'.

A Chemo-Ecological Investigation of Dendrilla antarctica Topsent, 1905: Identification of Deceptionin and the Effects of Heat Stress and Predation Pressure on Its Terpene Profiles.

Marine sponges usually host a wide array of secondary metabolites that play crucial roles in their biological interactions. The factors that influence the intraspecific variability in the metabolic profile of organisms, their production or ecological function remain generally unknown. Understanding this may help predict changes in biological relationships due to environmental variations as a consequence of climate change. The sponge Dendrilla antarctica is common in shallow rocky bottoms of the Antarctic Peninsula and is known to produce diterpenes that are supposed to have defensive roles. Here we used GC-MS to determine the major diterpenes in two populations of D. antarctica from two islands, Livingston and Deception Island (South Shetland Islands). To assess the potential effect of heat stress, we exposed the sponge in aquaria to a control temperature (similar to local), heat stress (five degrees higher) and extreme heat stress (ten degrees higher). To test for defence induction by predation pressure, we exposed the sponges to the sea star Odontaster validus and the amphipod Cheirimedon femoratus. Seven major diterpenes were isolated and identified from the samples. While six of them were already reported in the literature, we identified one new aplysulphurane derivative that was more abundant in the samples from Deception Island, so we named it deceptionin (7). The samples were separated in the PCA space according to the island of collection, with 9,11-dihydrogracilin A (1) being more abundant in the samples from Livingston, and deceptionin (7) in the samples from Deception. We found a slight effect of heat stress on the diterpene profiles of D. antarctica, with tetrahydroaplysulphurin-1 (6) and the gracilane norditerpene 2 being more abundant in the group exposed to heat stress. Predation pressure did not seem to influence the metabolite production. Further research on the bioactivity of D. antarctica secondary metabolites, and their responses to environmental changes will help better understand the functioning and fate of the Antarctic benthos.

Transcriptome analysis reveals the molecular mechanisms of heterosis on thermal resistance in hybrid tilapia (Oreochromi niloticus ♀×Oreochromi aureus ♂)

Heterosis is a widely observed biological phenomenon in fishes, in which hybrids exhibit superior traits to their parents. However, the underlying molecular mechanisms for heterosis are not well understood. Tilapia is an economically important aquaculture resource with high commercial value, and the phenomenon of high temperature tolerance in hybrid tilapia (Oreochromis niloticus ♀ × Oreochromis aureus ♂, AN) has been observed in recent studies. Uncovering the molecular mechanisms underlying this phenomenon could provide theoretical support for heterosis in thermal tolerance. To investigate the gene expression patterns and alternative splicing events associated with heat stress in tilapia, RNA Sequencing was conducted at control temperature (28 °C) and heat stress temperatures (36 °C and 39 °C). A total of 280, 260, and 261 genes with significantly divergent alternative splicing events were identified in O.niloticus (NL), O.aureus (AR), and O. niloticus ♀ × O.aureus ♂ (AN), respectively. In the heat stress groups (39 °C groups), 83.59% (23779 out of 28446) of the expressed genes showed non-additive expression patterns, and the highest proportion (35.14%) of these genes exhibited over-dominance expression patterns. KEGG pathway enrichment analysis showed that the overlapping genes among common differentially expressed genes (DEGs) and non-additively expressed genes (NAGs) were significantly enriched in apoptosis, adipocytokine signaling, and insulin signaling pathways. Furthermore, among these overlapping genes, 32 genes had undergone alternative splicing events in AN, which may play an important role in the thermal resistance of hybrid tilapia. These findings shed light on the physiological regulation mechanisms that allow hybrid tilapia to exhibit better thermal resistance than their parents. They provide important insights into the molecular basis of heterosis in tilapia and have potential implications for improving aquaculture practices.