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  1. High thermal stress responses of Echinolittorina snails at their range edge predict population vulnerability to future warming
    Han GD, Cartwright SR, Ganmanee M, Chan BKK, Adzis KAA, Hutchinson N, et al.
    Sci Total Environ, 2019 Jan 10;647:763-771.
    PMID: 30092533 DOI: 10.1016/j.scitotenv.2018.08.005
    Populations at the edge of their species' distribution ranges are typically living at the physiological extreme of the environmental conditions they can tolerate. As a species' response to global change is likely to be largely determined by its physiological performance, subsequent changes in environmental conditions can profoundly influence populations at range edges, resulting in range extensions or retractions. To understand the differential physiological performance among populations at their distribution range edge and center, we measured levels of mRNA for heat shock protein 70 (hsp70) as an indicator of temperature sensitivity in two high-shore littorinid snails, Echinolittorina malaccana and E. radiata, between 1°N to 36°N along the NW Pacific coast. These Echinolittorina snails are extremely heat-tolerant and frequently experience environmental temperatures in excess of 55 °C when emersed. It was assumed that animals exhibiting high temperature sensitivity will synthesize higher levels of mRNA, which will thus lead to higher energetic costs for thermal defense. Populations showed significant geographic variation in temperature sensitivity along their range. Snails at the northern range edge of E. malaccana and southern range edge of E. radiata exhibited higher levels of hsp70 expression than individuals collected from populations at the center of their respective ranges. The high levels of hsp70 mRNA in populations at the edge of a species' distribution range may serve as an adaptive response to locally stressful thermal environments, suggesting populations at the edge of their distribution range are potentially more sensitive to future global warming.
    Matched MeSH terms: Heat-Shock Response/physiology*
  2. Unfamiliar partnerships limit cnidarian holobiont acclimation to warming
    Herrera M, Klein SG, Schmidt-Roach S, Campana S, Cziesielski MJ, Chen JE, et al.
    Glob Chang Biol, 2020 Jul 06.
    PMID: 32627905 DOI: 10.1111/gcb.15263
    Enhancing the resilience of corals to rising temperatures is now a matter of urgency, leading to growing efforts to explore the use of heat tolerant symbiont species to improve their thermal resilience. The notion that adaptive traits can be retained by transferring the symbionts alone, however, challenges the holobiont concept, a fundamental paradigm in coral research. Holobiont traits are products of a specific community (holobiont) and all its co-evolutionary and local adaptations, which might limit the retention or transference of holobiont traits by exchanging only one partner. Here, we evaluate how interchanging partners affect the short- and long-term performance of holobionts under heat stress using clonal lineages of the cnidarian model system Aiptasia (host and Symbiodiniaceae strains) originating from distinct thermal environments. Our results show that holobionts from more thermally variable environments have higher plasticity to heat stress, but this resilience could not be transferred to other host genotypes through the exchange of symbionts. Importantly, our findings highlight the role of the host in determining holobiont productivity in response to thermal stress and indicate that local adaptations of holobionts will likely limit the efficacy of interchanging unfamiliar compartments to enhance thermal tolerance.
    Matched MeSH terms: Heat-Shock Response
  3. Heat and Wheat: Adaptation strategies with respect to heat shock proteins and antioxidant potential; an era of climate change
    Abasi F, Raja NI, Mashwani ZU, Ehsan M, Ali H, Shahbaz M
    Int J Biol Macromol, 2024 Jan;256(Pt 1):128379.
    PMID: 38000583 DOI: 10.1016/j.ijbiomac.2023.128379
    Extreme changes in weather including heat-wave and high-temperature fluctuations are predicted to increase in intensity and duration due to climate change. Wheat being a major staple crop is under severe threat of heat stress especially during the grain-filling stage. Widespread food insecurity underscores the critical need to comprehend crop responses to forthcoming climatic shifts, pivotal for devising adaptive strategies ensuring sustainable crop productivity. This review addresses insights concerning antioxidant, physiological, molecular impacts, tolerance mechanisms, and nanotechnology-based strategies and how wheat copes with heat stress at the reproductive stage. In this study stress resilience strategies were documented for sustainable grain production under heat stress at reproductive stage. Additionally, the mechanisms of heat resilience including gene expression, nanomaterials that trigger transcription factors, (HSPs) during stress, and physiological and antioxidant traits were explored. The most reliable method to improve plant resilience to heat stress must include nano-biotechnology-based strategies, such as the adoption of nano-fertilizers in climate-smart practices and the use of advanced molecular approaches. Notably, the novel resistance genes through advanced molecular approach and nanomaterials exhibit promise for incorporation into wheat cultivars, conferring resilience against imminent adverse environmental conditions. This review will help scientific communities in thermo-tolerance wheat cultivars and new emerging strategies to mitigate the deleterious impact of heat stress.
    Matched MeSH terms: Heat-Shock Response
  4. Fulltext Non-lethal heat shock increased Hsp70 and immune protein transcripts but not Vibrio tolerance in the white-leg shrimp
    Loc NH, Macrae TH, Musa N, Bin Abdullah MD, Abdul Wahid ME, Sung YY
    PLoS One, 2013;8(9):e73199.
    PMID: 24039886 DOI: 10.1371/journal.pone.0073199
    Non-lethal heat shock boosts bacterial and viral disease tolerance in shrimp, possibly due to increases in endogenous heat shock protein 70 (Hsp70) and/or immune proteins. To further understand the mechanisms protecting shrimp against infection, Hsp70 and the mRNAs encoding the immune-related proteins prophenoloxidase (proPO), peroxinectin, penaeidin, crustin and hemocyanin were studied in post-larvae of the white-leg shrimp Litopenaeus vannamei, following a non-lethal heat shock. As indicated by RT-qPCR, a 30 min abrupt heat shock increased Hsp70 mRNA in comparison to non-heated animals. Immunoprobing of western blots and quantification by ELISA revealed that Hsp70 production after heat shock was correlated with enhanced Hsp70 mRNA. proPO and hemocyanin mRNA levels were augmented, whereas peroxinectin and crustin mRNA levels were unchanged following non-lethal heat shock. Penaeidin mRNA was decreased by all heat shock treatments. Thirty min abrupt heat shock failed to improve survival of post-larvae in a standardized challenge test with Vibrio harveyi, indicating that under the conditions of this study, L. vannamei tolerance to Vibrio infection was influenced neither by Hsp70 accumulation nor the changes in the immune-related proteins, observations dissimilar to other shrimp species examined.
    Matched MeSH terms: Heat-Shock Response/genetics*; Heat-Shock Response/immunology
  5. Fulltext Physiological responses of 3 chicken breeds to acute heat stress
    Soleimani AF, Zulkifli I, Omar AR, Raha AR
    Poult Sci, 2011 Jul;90(7):1435-40.
    PMID: 21673158 DOI: 10.3382/ps.2011-01381
    Domestic animals have been modified by selecting individuals exhibiting desirable traits and culling the others. To investigate the alterations introduced by domestication and selective breeding in heat stress response, 2 experiments were conducted using Red Jungle Fowl (RJF), village fowl (VF), and commercial broilers (CB). In experiment 1, RJF, VF, and CB of a common chronological age (30 d old) were exposed to 36 ± 1°C for 3 h. In experiment 2, RJF, VF, and CB of common BW (930 ± 15 g) were subjected to similar procedures as in experiment 1. Heat treatment significantly increased body temperature, heterophil:lymphocyte ratio, and plasma corticosterone concentration in CB but not in VF and RJF. In both experiments and irrespective of stage of heat treatment, RJF showed lower heterophil:lymphocyte ratio, higher plasma corticosterone concentration, and higher heat shock protein 70 expression than VF and CB. It can be concluded that selective breeding for phenotypic traits in the domestication process has resulted in alterations in the physiology of CB and concomitantly the ability to withstand high ambient temperature compared with RJF and VF. In other words, domestication and selective breeding are leading to individuals that are more susceptible to stress rather than resistant. It is also apparent that genetic differences in body size and age per se may not determine breed or strain variations in response to heat stress.
    Matched MeSH terms: Heat-Shock Response/genetics; Heat-Shock Response/physiology*
  6. Impact of heat stress on health-related symptoms and physiological changes among workers at a palm oil mill in Mukah, Sarawak, Malaysia
    Vallennie V, Isa SNI, Mazlan AZ, Shaifuddin SNM
    Med J Malaysia, 2024 Mar;79(Suppl 1):82-87.
    PMID: 38555890
    INTRODUCTION: The palm oil (PO) industry is one of the most important sectors in the Malaysian economy. Workers at PO mills are, however, at risk for a number of health and safety issues, including heat stress, as the PO is one of the industries with high heat exposure. Heat stress occurs when a person's body cannot get rid of excess heat. Heat stress can result in heat cramps, heat exhaustion, heat rash, and heat stroke. It also results in physiological and psychological changes that can have an impact on a worker's performance. Therefore, this study aimed to evaluate the impact of heat stress on health-related symptoms and physiological changes among workers in a PO mill.

    MATERIALS AND METHODS: This cross-sectional study was conducted in a PO mill located in Mukah, Sarawak, Malaysia. Thirty-one workers from the four workstations (sterilizer, boiler, oil, and engine rooms) were selected as the respondents in this study. Wet Bulb Globe Thermometer was used in this study to measure the environmental temperature (WBGTin). Body core temperature (BCT), blood pressure (BP), and heart rate (HR) were recorded both before and after working in order to assess the physiological effects of heat stress on workers. A set of questionnaires were used to determine sociodemographic characteristics of the respondents and their symptoms related to heat stress. Data were then analyzed using SPSS Ver28.

    RESULTS: The WBGTin was found to be above the ACGIH threshold limit value of heat stress exposure in the engine room, sterilizer, and boiler workstations (>28.0°C). Additionally, there was a significant difference in the worker's BCT in these three workstations before and after work (p<0.05). Only the systolic BP and HR of those working at the boiler workstation showed significant difference between before and after work (p<0.05). The most typical symptoms that workers experience as a result of being exposed to heat at work include headache and fatigue. However, statistical analysis using Spearman Rho's test showed that there is no correlation between heat stress level with physiological changes and health-related symptoms among study respondents (p>0.05).

    CONCLUSION: Results of the present study confirmed that workers in PO mill were exposed to high temperatures while at work. Although the evidence indicates the physiological parameters in general are not significantly affected while working, it also demonstrated that worker's body adapts and acclimates to the level of heat. Even so, precautions should still be taken to reduce future heat exposure. It is recommended that a physiological study be carried out that focuses on cognitive function impairment to support the evidence regarding the effects of heat stress on PO mill workers.

    Matched MeSH terms: Heat-Shock Response
  7. Fulltext Non-Lethal Heat Shock of the Asian Green Mussel, Perna viridis, Promotes Hsp70 Synthesis, Induces Thermotolerance and Protects Against Vibrio Infection
    Aleng NA, Sung YY, MacRae TH, Abd Wahid ME
    PLoS One, 2015;10(8):e0135603.
    PMID: 26288319 DOI: 10.1371/journal.pone.0135603
    Mild heat stress promotes thermotolerance and protection against several different stresses in aquatic animals, consequences correlated with the accumulation of heat shock protein 70 (Hsp70). The purpose of this study was to determine if non-lethal heat shock (NLHS) of the Asian green mussel, Perna viridis, an aquatic species of commercial value, promoted the production of Hsp70 and enhanced its resistance to stresses. Initially, the LT50 and LHT for P. viridis were determined to be 42°C and 44°C, respectively, with no heat shock induced death of mussels at 40°C or less. Immunoprobing of western blots revealed augmentation of constitutive (PvHsp70-1) and inducible (PvHsp70-2) Hsp70 in tissue from adductor muscle, foot, gill and mantel of P. viridis exposed to 38°C for 30 min followed by 6 h recovery, NLHS conditions for this organism. Characterization by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that PvHsp70-1 and PvHsp70-2 respectively corresponded most closely to Hsp70 from P. viridis and Mytilus galloprovincialis. Priming of adult mussels with NLHS promoted thermotolerance and increased resistance to V. alginolyticus. The induction of Hsp70 in parallel with enhanced thermotolerance and improved protection against V. alginolyticus, suggests Hsp70 functions in P. viridis as a molecular chaperone and as a stimulator of the immune system.
    Matched MeSH terms: Heat-Shock Response/physiology*
  8. Heat shock response and metabolic stress in the tropical estuarine copepod Pseudodiaptomus annandalei converge at its upper thermal optimum
    Low JSY, Chew LL, Ng CC, Goh HC, Lehette P, Chong VC
    J Therm Biol, 2018 May;74:14-22.
    PMID: 29801619 DOI: 10.1016/j.jtherbio.2018.02.012
    Heat shock response (HSR), in terms of transcription regulation of two heat shock proteins genes hsp70 and hsp90), was analysed in a widespread tropical copepod Pseudodiaptomus annandalei. The mRNA transcripts of both genes were quantified after copepods at a salinity of 20 underwent an acclimation process involving an initial acclimation temperature of 29 °C, followed by gradual thermal ramping to the target exposure temperature range of 24-36 °C. The respective cellular HSR and organismal metabolism, measured by respiratory activity at exposure temperatures, were compared. The fold change in mRNA expression for both hsp70 and hsp90 (8-9 fold) peaks at 32 °C, which is very close to 32.4 °C, the upper thermal optimum for respiration in the species. Unexpectedly, the modelled HSR curves peak at only 3 °C (hsp90) and 3.5 °C (hsp70) above the mean water temperature (29.32 °C) of the copepod in the field. We propose that copepods in tropical waters adopt a preparative HSR strategy, early at the upper limit of its thermal optimum, due to the narrow thermal range of its habitat thus precluding substantial energy demand at higher temperatures. However, the model suggests that the species could survive to at least 36 °C with short acclimation time. Nevertheless, the significant overlap between its thermal range of hsp synthesis and the narrow temperature range of its habitat also suggests that any unprecedented rise in sea temperature would have a detrimental effect on the species.
    Matched MeSH terms: Heat-Shock Response*
  9. Differences in dry-bulb temperature do not influence moderate-duration exercise performance in warm environments when vapor pressure is equivalent
    Lei TH, Schlader ZJ, Che Muhamed AM, Zheng H, Stannard SR, Kondo N, et al.
    Eur J Appl Physiol, 2020 Apr;120(4):841-852.
    PMID: 32072226 DOI: 10.1007/s00421-020-04322-8
    PURPOSE: Recent studies have determined that ambient humidity plays a more important role in aerobic performance than dry-bulb temperature does in warm environments; however, no studies have kept humidity constant and independently manipulated temperature. Therefore, the purpose of this study was to determine the contribution of dry-bulb temperature, when vapor pressure was matched, on the thermoregulatory, perceptual and performance responses to a 30-min cycling work trial.

    METHODS: Fourteen trained male cyclists (age: 32 ± 12 year; height: 178 ± 6 cm; mass: 76 ± 9 kg; [Formula: see text]: 59 ± 9 mL kg-1 min-1; body surface area: 1.93 ± 0.12 m2; peak power output: 393 ± 53 W) volunteered, and underwent 1 exercise bout in moderate heat (MOD: 34.9 ± 0.2 °C, 50.1 ± 1.1% relative humidity) and 1 in mild heat (MILD: 29.2 ± 0.2 °C, 69.4 ± 0.9% relative humidity) matched for vapor pressure (2.8 ± 0.1 kPa), with trials counterbalanced.

    RESULTS: Despite a higher weighted mean skin temperature during MOD (36.3 ± 0.5 vs. 34.5 ± 0.6 °C, p 

    Matched MeSH terms: Heat-Shock Response/physiology*
  10. In vitro and in vivo thermal stress induces proliferation of Blastocystis sp
    Thergarajan G, Govind SK, Bhassu S
    Parasitol Res, 2018 Jan;117(1):177-187.
    PMID: 29188368 DOI: 10.1007/s00436-017-5688-3
    Blastocystis sp. is known to be the most commonly found intestinal protozoan parasite in human fecal surveys and has been incriminated to cause diarrhea and abdominal bloating. Binary fission has been widely accepted as the plausible mode of reproduction for this parasite. The present study demonstrates that subjecting the parasites in vitro to higher temperature shows the proliferation of parasite numbers in cultures. Transmission electron microscopy was used to compare the morphology of Blastocystis sp. subtype 3 isolated from a dengue patient having high fever (in vivo thermal stress) and Blastocystis sp. 3 maintained at 41 °C (in vitro thermal stress) and 37 °C (control). Fluorescence stains like acridine orange (AO) and 4',6'-diamino-2-phenylindole (DAPI) were used to demonstrate the viability and nuclear content of the parasite for both the in vitro and in vivo thermal stress groups of parasites. Blastocystis sp. at 37 °C was found to be mostly vacuolar whereas the in vitro thermal stressed isolates at 41 °C were granular with electron dense material seen to protect the granules within the central body. Parasites of the in vivo thermal stressed group showed similar ultrastructure as the in vitro ones. AO and DAPI staining provided evidence that these granules are viable which develop into progenies of Blastocystis sp. These granular forms were then observed to rupture and release progenies from the mother cells whilst the peripheral cytoplasmic walls were seen to degrade. Upon exposure to high temperature both in vitro and in vivo, Blastocystis sp. in cultures show higher number of granular forms seen to be protected by the electron dense material within the central body possibly acting as a protective mechanism. This is possibly to ensure the ability to survive for the granules to be developed as viable progenies for release into the host system.
    Matched MeSH terms: Heat-Shock Response*
  11. Fulltext Identification and characterisation of heat shock protein 70 in thermal stressed Blastocystis sp
    Gaythri T, Suresh K, Subha B, Kalyani R
    PLoS One, 2014;9(9):e95608.
    PMID: 25180903 DOI: 10.1371/journal.pone.0095608
    Protistan parasites in order to ensure their viability and demonstrate successful progression in their life cycle need to respond towards various environmental stressors. Blastocystis sp. is known to be the most commonly found intestinal protistan parasite in any human stool surveys and has been incriminated to be responsible for diarrhea and bloating stomach. The present study demonstrates for the first time the presence of HSP70 in subtypes of Blastocystis sp. when the cultures were subjected to temperature of 39 and 41 °C where the growth of parasites was reduced to a minimum to majority being granular forms. The growth of parasites exposed to higher temperatures however doubled compared to the controls when the parasites were re-cultured back at 37 °C. Upon thermal stress at 41 °C, subtype 3 and subtype 5 isolates' growth reached up to 2.97 × 10(6) and 3.05 × 10(6) cells/ml compared to their respective controlled culture tubes at 37 °C which peaked only at 1.34 × 10(6) and 1.70 × 10(6) cells/ml respectively. The designed primer set that amplified Blastocystis sp. subtype 7 HSP70 gene in subtypes 1, 3 and 5 was against a conserved region. The gene was amplified at 318 bp. The multiple sequence alignment showed that the targeted sequence length ranges from 291-295 bp. The pair wise alignment result showed that the sequence identity among the four sequence ranges from 88% to 96%. These findings were further evidenced by the up regulation of HSP70 gene in thermal stressed isolates of subtype 3 and 5 at 41 °C. Higher number of granular forms was significantly found in thermal stressed isolates of subtype 3 and 5 which implicates that this life cycle stage has a role in responding to thermal stress.
    Matched MeSH terms: Heat-Shock Response*
  12. RpoS differentially affects the general stress response and biofilm formation in the endophytic Serratia plymuthica G3
    Liu X, Wu Y, Chen Y, Xu F, Halliday N, Gao K, et al.
    Res. Microbiol., 2016 Apr;167(3):168-77.
    PMID: 26671319 DOI: 10.1016/j.resmic.2015.11.003
    The σ(S) subunit RpoS of RNA polymerase functions as a master regulator of the general stress response in Escherichia coli and related bacteria. RpoS has been reported to modulate biocontrol properties in the rhizobacterium Serratia plymuthica IC1270. However, the role of RpoS in the stress response and biofilm formation in S. plymuthica remains largely unknown. Here we studied the role of RpoS from an endophytic S. plymuthica G3 in regulating these phenotypes. Mutational analysis demonstrated that RpoS positively regulates the global stress response to acid or alkaline stresses, oxidative stress, hyperosmolarity, heat shock and carbon starvation, in addition to proteolytic and chitinolytic activities. Interestingly, rpoS mutations resulted in significantly enhanced swimming motility, biofilm formation and production of the plant auxin indole-3-acetic acid (IAA), which may contribute to competitive colonization and environmental fitness for survival. These findings provide further insight into the strain-specific role of RpoS in the endophytic strain G3 of S. plymuthica, where it confers resistance to general stresses encountered within the plant environment. The heterogeneous functionality of RpoS in rhizosphere and endophytic S. plymuthica populations may provide a selective advantage for better adaptation to various physiological and environmental stresses.
    Matched MeSH terms: Heat-Shock Response
  13. Fulltext Transcriptome analysis of Pseudomonas aeruginosa PAO1 grown at both body and elevated temperatures
    Chan KG, Priya K, Chang CY, Abdul Rahman AY, Tee KK, Yin WF
    PeerJ, 2016;4:e2223.
    PMID: 27547539 DOI: 10.7717/peerj.2223
    Functional genomics research can give us valuable insights into bacterial gene function. RNA Sequencing (RNA-seq) can generate information on transcript abundance in bacteria following abiotic stress treatments. In this study, we used the RNA-seq technique to study the transcriptomes of the opportunistic nosocomial pathogen Pseudomonas aeruginosa PAO1 following heat shock. Samples were grown at both the human body temperature (37 °C) and an arbitrarily-selected temperature of 46 °C. In this work using RNA-seq, we identified 133 genes that are differentially expressed at 46 °C compared to the human body temperature. Our work identifies some key P. aeruginosa PAO1 genes whose products have importance in both environmental adaptation as well as in vivo infection in febrile hosts. More importantly, our transcriptomic results show that many genes are only expressed when subjected to heat shock. Because the RNA-seq can generate high throughput gene expression profiles, our work reveals many unanticipated genes with further work to be done exploring such genes products.
    Matched MeSH terms: Heat-Shock Response
  14. Tigecycline resistance may be associated with dysregulated response to stress in Mycobacterium abscessus
    Ng HF, Ngeow YF, Yap SF, Zin T, Tan JL
    Int J Med Microbiol, 2019 Nov 18.
    PMID: 31784213 DOI: 10.1016/j.ijmm.2019.151380
    Previously, we characterized 7C, a laboratory-derived tigecycline-resistant mutant of Mycobacterium abscessus ATCC 19977, and found that the resistance was conferred by a mutation in MAB_3542c, which encodes an RshA-like protein. In M. tuberculosis, RshA is an anti-sigma factor that negatively regulates the SigH-dependent heat/oxidative stress response. We hypothesized that this mutation in 7C might dysregulate the stress response which has been generally linked to antibiotic resistance. In this study, we tested this hypothesis by subjecting 7C to transcriptomic dissection using RNA sequencing. We found an over-expression of genes encoding the SigH ortholog, chaperones and oxidoreductases. In line with these findings, 7C demonstrated better survival against heat shock when compared to the wild-type ATCC 19977. Another interesting observation from the RNA-Seq analysis was the down-regulation of ribosomal protein-encoding genes. This highlights the possibility of ribosomal conformation changes which could negatively affect the binding of tigecycline to its target, leading to phenotypic resistance. We also demonstrated that transient resistance to tigecycline could be induced in the ATCC 19977 by elevated temperature. Taken together, these findings suggest that dysregulated stress response may be associated with tigecycline resistance in M. abscessus.
    Matched MeSH terms: Heat-Shock Response
  15. Comparison of thermoregulatory responses to heat between Malaysian and Japanese males during leg immersion
    Wijayanto T, Wakabayashi H, Lee JY, Hashiguchi N, Saat M, Tochihara Y
    Int J Biometeorol, 2011 Jul;55(4):491-500.
    PMID: 20824480 DOI: 10.1007/s00484-010-0358-5
    The objective of this study was to investigate thermoregulatory responses to heat in tropical (Malaysian) and temperate (Japanese) natives, during 60 min of passive heating. Ten Japanese (mean ages: 20.8 ± 0.9 years) and ten Malaysian males (mean ages: 22.3 ± 1.6 years) with matched morphological characteristics and physical fitness participated in this study. Passive heating was induced through leg immersion in hot water (42°C) for 60 min under conditions of 28°C air temperature and 50% RH. Local sweat rate on the forehead and thigh were significantly lower in Malaysians during leg immersion, but no significant differences in total sweat rate were observed between Malaysians (86.3 ± 11.8 g m(-2) h(-1)) and Japanese (83.2 ± 6.4 g m(-2) h(-1)) after leg immersion. In addition, Malaysians displayed a smaller rise in rectal temperature (0.3 ± 0.1°C) than Japanese (0.7 ± 0.1°C) during leg immersion, with a greater increase in hand skin temperature. Skin blood flow was significantly lower on the forehead and forearm in Malaysians during leg immersion. No significant different in mean skin temperature during leg immersion was observed between the two groups. These findings indicated that regional differences in body sweating distribution might exist between Malaysians and Japanese during heat exposure, with more uniform distribution of local sweat rate over the whole body among tropical Malaysians. Altogether, Malaysians appear to display enhanced efficiency of thermal sweating and thermoregulatory responses in dissipating heat loss during heat loading. Thermoregulatory differences between tropical and temperate natives in this study can be interpreted as a result of heat adaptations to physiological function.
    Matched MeSH terms: Heat-Shock Response/physiology
  16. Fulltext Cyst viability and stress tolerance upon heat shock protein 70 knockdown in the brine shrimp Artemia franciscana
    Iryani MTM, Sorgeloos P, Danish-Daniel M, Tan MP, Wong LL, Mok WJ, et al.
    Cell Stress Chaperones, 2020 Nov;25(6):1099-1103.
    PMID: 32383141 DOI: 10.1007/s12192-020-01113-0
    Females of the brine shrimp Artemia franciscana produce either free-swimming nauplii via ovoviviparous pathway of reproduction or encysted embryos, known as cysts, via oviparous pathway, in which biological processes are arrested. While previous study has shown a crucial role of ATP-dependent molecular chaperone, heat shock protein 70 (Hsp70) in protecting A. franciscana nauplii against various abiotic and abiotic stressors, the function of this protein in diapausing embryos and cyst development, however, remains unknown. RNA interference (RNAi) was applied in this study to examine the role of Hsp70 in cyst development and stress tolerance, with the latter performed by desiccation and freezing, a common method used for diapause termination in Artemia cysts. Hsp70 knockdown was apparent in cysts released from females that were injected with Hsp70 dsRNA. The loss of Hsp70 affected neither the development nor morphology of the cysts. The time between fertilization and cyst release from Artemia females injected with Hsp70 dsRNA was delayed slightly, but the differences were not significant when compared to the controls. However, the hatching percentage of cysts which lacks Hsp70 were reduced following desiccation and freezing. Taken together, these results indicated that Hsp70 possibly plays a role in the stress tolerance but not in the development of diapause-destined embryos of Artemia. This research makes fundamental contributions to our understanding of the role molecular chaperone Hsp70 plays in Artemia, an excellent model organism for diapause studies of the crustaceans.
    Matched MeSH terms: Heat-Shock Response*
  17. Fulltext Neonatal feed restriction modulates circulating levels of corticosterone and expression of glucocorticoid receptor and heat shock protein 70 in aged Japanese quail exposed to acute heat stress
    Soleimani AF, Zulkifli I, Omar AR, Raha AR
    Poult Sci, 2011 Jul;90(7):1427-34.
    PMID: 21673157 DOI: 10.3382/ps.2011-01403
    This study aimed to determine the effect of neonatal feed restriction on plasma corticosterone concentration (CORT), hippocampal glucocorticoid receptor (GR) expression, and heat shock protein (Hsp) 70 expression in aged male Japanese quail subjected to acute heat stress. Equal numbers of chicks were subjected to either ad libitum feeding (AL) or 60% feed restriction on d 4, 5, and 6 (FR). At 21 (young) and 270 (aged) d of age, birds were exposed to 43 ± 1°C for 1 h. Blood and hippocampus samples were collected to determine CORT and Hsp 70 and GR expressions before heat stress and following 1 h of heat stress, 1 h of post-heat stress recovery, and 2 h of post-heat stress recovery. With the use of real-time PCR and enzyme immunoassay, we examined the hippocampal expression of GR and Hsp 70 and CORT. The GR expression of the young birds increased following heat stress and remained consistent throughout the period of recovery. Conversely, no significant changes were noted on GR expression of aged birds. Although both young and aged birds had similar CORT before and during heat stress, the latter exhibited greater values following 1 and 2 h of recovery. Within the young group, feeding regimens had no significant effect on Hsp 70 expression. However, neonatal feed restriction improved Hsp 70 expression in aged birds. Neonatal feed restriction, compared with the AL group, resulted in higher CORT on d 21 but the converse was noted on d 270. Neonatal feed restriction appears to set a robust reactive hypothalamo-pituitary-adrenal response allowing the development of adaptive, healthy, and resilient phenotypes in aged quail as measured by a higher hippocampal Hsp 70 expression along with lower CORT.
    Matched MeSH terms: Heat-Shock Response/physiology*
  18. Comparison of heat dissipation response between Malaysian and Japanese males during exercise in humid heat stress
    Wakabayashi H, Wijayanto T, Lee JY, Hashiguchi N, Saat M, Tochihara Y
    Int J Biometeorol, 2011 Jul;55(4):509-17.
    PMID: 20949285 DOI: 10.1007/s00484-010-0374-5
    This study investigated the differences in heat dissipation response to intense heat stress during exercise in hot and humid environments between tropical and temperate indigenes with matched physical characteristics. Ten Japanese (JP) and ten Malaysian (MY) males participated in this study. Subjects performed exercise for 60 min at 55% peak oxygen uptake in 32°C air with 70% relative humidity, followed by 30 min recovery. The increase in rectal temperature (T(re)) was smaller in MY during exercise compared to JP. The local sweat rate and total body mass loss were similar in both groups. Both skin blood flow and mean skin temperature was lower in MY compared to JP. A significantly greater increase in hand skin temperature was observed in MY during exercise, which is attributable to heat loss due to the greater surface area to mass ratio and large number of arteriovenous anastomoses. Also, the smaller increase in T(re) in MY may be explained by the presence of a significantly greater core-skin temperature gradient in MY than JP. The thermal gradient is also a major factor in increasing the convective heat transfer from core to skin as well as skin blood flow. It is concluded that the greater core-skin temperature gradient observed in MY is responsible for the smaller increase in T(re).
    Matched MeSH terms: Heat-Shock Response/physiology*
  19. Fulltext SA-Mediated Regulation and Control of Abiotic Stress Tolerance in Rice
    Nadarajah K, Abdul Hamid NW, Abdul Rahman NSN
    Int J Mol Sci, 2021 May 25;22(11).
    PMID: 34070465 DOI: 10.3390/ijms22115591
    Environmental or abiotic stresses are a common threat that remains a constant and common challenge to all plants. These threats whether singular or in combination can have devastating effects on plants. As a semiaquatic plant, rice succumbs to the same threats. Here we systematically look into the involvement of salicylic acid (SA) in the regulation of abiotic stress in rice. Studies have shown that the level of endogenous salicylic acid (SA) is high in rice compared to any other plant species. The reason behind this elevated level and the contribution of this molecule towards abiotic stress management and other underlying mechanisms remains poorly understood in rice. In this review we will address various abiotic stresses that affect the biochemistry and physiology of rice and the role played by SA in its regulation. Further, this review will elucidate the potential mechanisms that control SA-mediated stress tolerance in rice, leading to future prospects and direction for investigation.
    Matched MeSH terms: Heat-Shock Response/physiology
  20. Fulltext Effects of zinc oxide nanoparticles on regulatory appetite and heat stress protein genes in broiler chickens subjected to heat stress
    Ramiah SK, Atta Awad E, Hemly NIM, Ebrahimi M, Joshua O, Jamshed M, et al.
    J Anim Sci, 2020 Oct 01;98(10).
    PMID: 32936879 DOI: 10.1093/jas/skaa300
    This study was conducted to explore the effect of the zinc oxide nanoparticles (ZnONPs) supplement on the regulatory appetite and heat stress (HS) genes in broiler chickens raised under high or normal ambient temperatures. In this study, 240 one-day-old male broiler chicks (Cobb 500) were randomly assigned to 48 battery cages. From day 1, these 48 cages were randomly subjected to four different treatment strategies: Control (wherein, their basal diet included 60 mg/kg of ZnO), ZNONPs 40 (wherein basal diet included 40 mg/kg of ZnONPs), ZnONPs 60 (basal diet included 60 mg/kg of ZnONPs), and ZnONPs 100 (basal diet included 100 mg/kg of ZnONPs). Thereafter, from day 22 to 42, the chickens from each dietary treatment group were subjected to different temperature stresses either normal (23 ± 1 °C constant) or HS (34 ± 1 °C for 6 h/d), which divided them into eight different treatment groups. Our findings revealed that dietary ZnONPs altered the gene expression of cholecystokinin (ileum), heat stress proteins (HSP) 70 (jejunum and ileum), and HSP 90 (duodenum, jejunum, and ileum). The gene expression of ghrelin was affected by the interaction between the ZnONPs concentration and temperature in the duodenum and stomach. More studies are required to elucidate its complex physiological and biochemical functions of the regulation of gene expression within the intestine in heat-stressed broiler chickens.
    Matched MeSH terms: Heat-Shock Response/drug effects
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