Exogenous melatonin enhances heat stress tolerance in sweetpotato by modulating antioxidant defense system,osmotic homeostasis and stomatal traits

Heat stress hinders the growth and productivity of sweetpotato plants,predominantly through oxidative damage to cellular membranes.Therefore,the development of efficient approaches for mitigating heat-related impairments is essential for the long-term production of sweetpotatoes.Melatonin has been recognised for its capacity to assist plants in dealing with abiotic stress conditions.This research aimed to investigate how different doses of exogenous melatonin influence heat damage in sweetpotato plants.Heat stress drastically affected shoot and root fresh weight by 31.8 and 44.5%,respectively.This reduction resulted in oxidative stress characterised by increased formation of hydrogen peroxide(H_(2)O_(2))by 804.4%,superoxide ion(O_(2)^(·-))by 211.5%and malondialdehyde(MDA)by 234.2%.Heat stress also reduced chlorophyll concentration,photosystemⅡefficiency(F_v/F_m)by 15.3%and gaseous exchange.However,pre-treatment with 100μmol L^(-1)melatonin increased growth and reduced oxidative damage to sweetpotato plants under heat stress.In particular,melatonin decreased H_(2)O_(2),O_(2)^(·-)and MDA by 64.8%,42.7%and 38.2%,respectively.Melatonin also mitigated the decline in chlorophyll levels and improved stomatal traits,gaseous exchange and F_(v)/F_(m)(13%).Results suggested that the favorable outcomes of melatonin treatment can be associated with elevated antioxidant enzyme activity and an increase in non-enzymatic antioxidants and osmo-protectants.Overall,these findings indicate that exogenous melatonin can improve heat stress tolerance in sweetpotatoes.This stu dy will assist re searchers in further investigating how melatonin makes sweetpotatoes more resistant to heat stress.

Effect of organic mineral supplementation in reducing oxidative stress in Holstein calves during short‑term heat stress and recovery conditions

Background This study investigated the effects of inorganic and organic minerals on physiological responses,oxidative stress reduction,and rumen microbiota in Holstein bull calves(123.81±9.76 kg;5 months old)during short-term heat stress(HS)and recovery periods.Eight Holstein calves were randomly assigned to four treatment groups:no mineral supplementation(Con),inorganic minerals(IM),organic minerals(OM),and high-concentration organic minerals(HOM)and two thermal environments(HS and recovery)using 4×2 factorial arrangement in a crossover design of four periods of 35 d.Calves were maintained in a temperature-controlled barn.The experimental period consisted of 14 d of HS,14 d of recovery condititon,and a 7-d washing period.Results Body temperature and respiration rate were higher in HS than in the recovery conditions(P<0.05).Selenium concentration in serum was high in the HOM-supplemented calves in both HS(90.38μg/dL)and recovery periods(102.00μg/dL)(P<0.05).During the HS period,the serum cortisol was 20.26 ng/mL in the HOM group,which was 5.60 ng/mL lower than in the control group(P<0.05).The total antioxidant status was the highest in the OM group(2.71 mmol Trolox equivalent/L),followed by the HOM group during HS,whereas it was highest in the HOM group(2.58 mmol Trolox equivalent/L)during the recovery period(P<0.05).Plasma malondialdehyde and HSP70 levels were decreased by HOM supplementation during the HS and recovery periods,whereas SOD and GPX levels were not significantly affected(P>0.05).The principal coordinate analysis represented that the overall rumen microbiota was not influenced by mineral supplementation;however,temperature-induced microbial structure shifts were indicated(PERMANOVA:P<0.05).At the phylum level,Firmicutes and Actinobacteria decreased,whereas Fibrobacteres,Spirochaetes,and Tenericutes increased(P<0.05),under HS conditions.The genus Treponema increased under HS conditions,while Christensenella was higher in recovery conditions(P<0.05).Conclusion HOM supplementation during HS reduced cortisol concentrations and increased total antioxidant status in Holstein bull calves,suggesting that high organic mineral supplementation may alleviate the adverse effects of HS.

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

Background High environmental temperatures induce heat stress in broiler chickens,affecting their health and pro-duction 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 baica-lein supplementation on growth performance and health parameters in heat-stressed broilers.Results Six 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℃ 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℃)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℃ for 8 h)in the CHS,TMHS,CHSS,and TMHSS groups.A thermoneutral(22–24℃)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.Conclusions Pre-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 produc-tion,and promote gut health by increasing beneficial microbial communities.

Heat stress induced hepatocyte apoptosis in largemouth bass Micropterus salmoides via IRE1α/TRAF2/ASK1/JNK pathway

Heat stress(HS)has been shown to adversely affect fish livers and can lead to extensive apoptosis.To investigate the relationship between endoplasmic reticulum(ER)stress and HS-induced apoptosis in fish livers,we isolated and cultured primary hepatocytes of largemouth bass,Micropterus salmoides by trypsin method,then established an in-vitro model of liver cells under HS(35℃).The contents of lactic dehydrogenase(LDH)and hydrogen peroxide(H2O2)were determined to evaluate the effects of HS on hepatocyte injury and oxidative stress.RT-qPCR was performed to discover the key genes in unfolded protein response(UPR)pathways involved at different HS duration.ERS inhibitor 4-PBA and IRE1αinhibitor 4μ8C were used to further investigate the effects of HS on IRE1αapoptosis pathway in hepatocytes.Results show that HS led to significant increases in the release of LDH,the content of H2O2,and the expressions of oxidative protein folding genes(ero1αand pdi)under HS,suggesting severe hepatocyte injury and oxidative stress happened in heat-stressed largemouth bass hepatocytes.The continuous activation of IRE1αpathway genes(grp78,grp94,atf6,perk,eif2a,atf4,chop,ire1α,traf2,ask1,jnk1,and jnk2)indicated that HS led significantly to ER stress.In particular,the mRNA expression levels of ER stress-related genes(grp78,grp94,atf6,perk,ire1α,chop,jnk1,and jnk2)in the high temperature(HT)+4-PBA group and the HT+4μ8C group were significantly down-regulated under HS.After 4μ8C treatment,the expression levels of apoptosis-related genes(caspase-2,caspase-3,caspase-6,caspase-7,caspase-8,caspase-9,and caspase-10)and LDH content were significantly decreased,whereas the cell survival rate was significantly increased when given 4-PBA or 4μ8C treatment.These findings demonstrate that HS could induce liver apoptosis of largemouth bass through the IRE1αpathway,which may act as a key switch mediating liver apoptosis of largemouth bass under HS.

Differential expression of miRNAs and mRNAs in the livers of largemouth bass Micropterus salmoides under heat stress

Global warming threatens freshwater ecosystems and compromises fish survival.To elucidate the role of miRNAs in the livers of heat stressed largemouth bass,juvenile fish was subject to heat stress under 37°C.Both mRNA-seq and miRNA-seq were conducted on the liver tissues under control and heat stress conditions.Differential gene expression analysis and enrichment analysis were performed on mRNA and miRNA expression profiles.A total of 406 differentially expressed genes(DEGs)were discovered,of which 212 were up-regulated and 194 were down-regulated.Most of the DEGs were significantly implicated in the regulation of“protein processing in endoplasmic reticulum”,“proteasome”,“steroid biosynthesis”,and“ornithine decarboxylase inhibitor activity”pathways.In addition,47 differentially expressed miRNAs(DEMs)were identified in largemouth bass livers under heat stress,including 21 up-regulated and 25 down-regulated miRNAs.A negatively regulated miRNA-mRNA network including 12 miRNAs and 19 mRNAs was constructed with DEMs involved in“protein degradation”,“calcium ion regulation”,“cell apoptosis”,and“lipid metabolism”.Moreover,this study indicated novel-miR-144 activated the IRE1 signaling pathway by targeting txndc5 to induce liver apoptosis in largemouth bass under heat stress.This study revealed the involvement of miRNA regulation in largemouth bass in response to heat stress.

Effects of heat stress and long photoperiod on the prostate of rats

Objective:To examine light and heat effects on the morphological,histological,and micrometric structure of the prostate of rats.Methods:Thirty adult male rats were divided into three groups.The control group was kept under 20℃-22℃ and an artificial 12 h/12 h day/night cycle;the temperature group was under normal light and at(42±1)℃ heat for 4 to 5 h daily,and the light group was exposed to 8 h/16 h day/night cycle with 20℃-22℃.Rats were weighed five times(at the beginning of the study and every seven days).Five milliliters(mL)of their peripheral blood were taken.The tissue staining was performed using the hematoxylin-eosin(H&E)stain and periodic acid-Schiff(PAS).In the following,tissue and cellular reactions to the PAS were examined.Results:Folds were located entirely on the surface of the anterior lobe and periphery of the other lobes.The secretory units in the anterior lobe were more than the lateral lobe.A strong reaction of the secretory cells to the PAS was observed.Testosterone serum levels of the light group also significantly increased compared to the control group(P<0.05).The most histometric changes of the lobes were established in the lateral lobes.Heat stress resulted in a significant decrease in testosterone levels and transformed prostate tissue.The epithelium and parenchyma to scaffold ratio in the temperature group decreased.Conclusions:Maximum and minimum changes in the ventral lobe happened under the ascent of temperature and light,respectively.The ventral lobe in the study of prostatic hyperplasia should be more considered.

Effects of Enteromorpha prolifera polysaccharides on growth performance,intestinal barrier function and cecal microbiota in yellow-feathered broilers under heat stress

Background Global warming leading to heat stress(HS)is becoming a major challenge for broiler production.This study aimed to explore the protective effects of seaweed(Enteromorpha prolifera)polysaccharides(EPS)on the intestinal barrier function,microbial ecology,and performance of broilers under HS.A total of 144 yellow-feathered broilers(male,56 days old)with 682.59±7.38 g were randomly assigned to 3 groups:1)TN(thermal neutral zone,23.6±1.8℃),2)HS(heat stress,33.2±1.5℃ for 10 h/d),and 3)HSE(HS+0.1%EPS).Each group contained 6 replicates with 8 broilers per replicate.The study was conducted for 4 weeks;feed intake and body weights were measured at the end of weeks 2 and 4.At the end of the feeding trial,small intestine samples were collected for histomorphology,antioxidant,secretory immunoglobulin A(s Ig A)content,apoptosis,gene and protein expression analysis;cecal contents were also collected for microbiota analysis based on 16S r DNA sequencing.Results Dietary EPS promoted the average daily gain(ADG)of broilers during 3–4 weeks of HS(P<0.05).At the end of HS on broilers,the activity of total superoxide dismutase(T-SOD),glutathione S-transferase(GST),and the content of s Ig A in jejunum were improved by EPS supplementation(P<0.05).Besides,dietary EPS reduced the epithelial cell apoptosis of jejunum and ileum in heat-stressed broilers(P<0.05).Addition of EPS in HS group broilers'diet upregulated the relative m RNA expression of Occludin,ZO-1,γ-GCLc and IL-10 of the jejunum(P<0.05),whereas downregulated the relative m RNA expression of NF-κB p65,TNF-αand IL-1βof the jejunum(P<0.05).Dietary EPS increased the protein expression of Occludin and ZO-1,whereas it reduced the protein expression of NF-κB p65 and MLCK(P<0.01)and tended to decrease the protein expression of TNF-α(P=0.094)in heat-stressed broilers.Furthermore,the proportions of Bacteroides and Oscillospira among the three groups were positively associated with jejunal apoptosis and pro-inflammatory cytokine expression(P<0.05)and negatively correlated with jejunal Occludin level(P<0.05).However,the proportions of Lactobacillus,Barnesiella,Subdoligranulum,Megasphaera,Collinsella,and Blautia among the three groups were positively related to ADG(P<0.05).Conclusions EPS can be used as a feed additive in yellow-feathered broilers.It effectively improves growth performance and alleviates HS-induced intestinal injury by relieving inflammatory damage and improving the tight junction proteins expression.These beneficial effects may be related to inhibiting NF-κB/MLCK signaling pathway activation and regulation of cecal microbiota.

Heat stress affects mammary metabolism by influencing the plasma flow to the glands

Background Environmental heat stress(HS)can have detrimental effects on milk production by compromising the mammary function.Mammary plasma flow(MPF)plays a crucial role in nutrient supply and uptake in the mam-mary gland.In this experiment,we investigated the physiological and metabolic changes in high-yielding cows exposed to different degrees of HS:no HS with thermal-humidity index(THI)below 68(No-HS),mild HS(Mild-HS,68≤THI≤79),and moderate HS(Mod-HS,79<THI≤88)in their natural environment.Our study focused on the changes in blood oxygen supply and mammary glucose uptake and utilization.Results Compared with No-HS,the MPF of dairy cows was greater(P<0.01)under Mild-HS,but was lower(P<0.01)in cows under Mod-HS.Oxygen supply and consumption exhibited similar changes to the MPF under different HS,with no difference in ratio of oxygen consumption to supply(P=0.46).The mammary arterio-vein differences in glucose concentration were lower(P<0.05)under Mild-and Mod-HS than under no HS.Glucose supply and flow were significantly increased(P<0.01)under Mild-HS but significantly decreased(P<0.01)under Mod-HS compared to No-HS.Glucose uptake(P<0.01)and clearance rates(P<0.01)were significantly reduced under Mod-HS compared to those under No-HS and Mild-HS.Under Mild-HS,there was a significant decrease(P<0.01)in the ratio of lac-tose yield to mammary glucose supply compared to that under No-HS and Mod-HS,with no difference(P=0.53)in the ratio of lactose yield to uptaken glucose among different HS situations.Conclusions Degrees of HS exert different influences on mammary metabolism,mainly by altering MPF in dairy cows.The output from this study may help us to develop strategies to mitigate the impact of different degrees of HS on milk production.

Supplementation of vitamin E or a botanical extract as antioxidants to improve growth performance and health of growing pigs housed under thermoneutral or heat-stressed conditions

Background Heat stress has severe negative consequences on performance and health of pigs,leading to significant economic losses.The objective of this study was to investigate the effects of supplemental vitamin E and a botanical extract in feed or drinking water on growth performance,intestinal health,and oxidative and immune status in grow-ing pigs housed under heat stress conditions.Methods Duplicate experiments were conducted,each using 64 crossbred pigs with an initial body weight of 50.7±3.8 and 43.9±3.6 kg and age of 13-week and 12-week,respectively.Pigs(n=128)were housed individually and assigned within weight blocks and sex to a 2×4 factorial arrangement consisting of 2 environments(thermo-neutral(21.2℃)or heat-stressed(30.9℃))and 4 supplementation treatments(control diet;control+100 IU/L of D-α-tocopherol in water;control+200 IU/kg of DL-α-tocopheryl-acetate in feed;or control+400 mg/kg of a botanical extract in feed).Results Heat stress for 28 d reduced(P≤0.001)final body weight,average daily gain,and average daily feed intake(-7.4 kg,-26.7%,and-25.4%,respectively)but no effects of supplementation were detected(P>0.05).Serum vitamin E increased(P<0.001)with vitamin E supplementation in water and in feed(1.64 vs.3.59 and 1.64 vs.3.24),but not for the botanical extract(1.64 vs.1.67 mg/kg)and was greater when supplemented in water vs.feed(P=0.002).Liver vitamin E increased(P<0.001)with vitamin E supplementations in water(3.9 vs.31.8)and feed(3.9 vs.18.0),but not with the botanical extract(3.9 vs.4.9 mg/kg).Serum malondialdehyde was reduced with heat stress on d 2,but increased on d 28(interaction,P<0.001),and was greater(P<0.05)for antioxidant supplementation compared to control.Cellular proliferation was reduced(P=0.037)in the jejunum under heat stress,but increased in the ileum when vitamin E was supplemented in feed and water under heat stress(interaction,P=0.04).Tumor necrosis factor-αin jejunum and ileum mucosa decreased by heat stress(P<0.05)and was reduced by vitamin E sup-plementations under heat stress(interaction,P<0.001).Conclusions The addition of the antioxidants in feed or in drinking water did not alleviate the negative impact of heat stress on feed intake and growth rate of growing pigs.

Impact of Dietary Lactobacillus plantarum Postbiotics on the Performance of Layer Hens under Heat Stress Conditions

This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa White layers, were subdivided into six treatments of 32 individually caged birds. Half of the birds were reared under regular temperature conditions, while the other half was subjected to cyclic daily heat stress. Layers were offered one of three diets: 1) Control;2) Control + Lactobacillus plantarum RS5 probiotic;3) Control + Lactobacillus plantarum RS5 postbiotics. Birds were tested for performance and visceral organ development for 5 months. Heat stress negatively affected the birds’ feed intake, egg weight, shell weight percentage, Haugh unit, shell thickness, yolk color, body weight and spleen weight percentage. Postbiotics significantly increased egg production (p < 0.05) in comparison to the control and the probiotic fed group (94.8% vs 92.6% vs 93.1%, respectively). Birds under probiotic or postbiotic diet showed a significantly higher (p < 0.05) feed intake and egg weight, although the probiotic had a more pronounced and gradual effect. Specific gravity, yolk weight percentage and shell thickness didn’t show differences among dietary groups. The Haugh Unit was significantly higher (p < 0.05) in probiotic group which also showed a significantly lower yolk color index (p < 0.05). The different feed treatments did not impact the bird’s viscera weight percentage, except for the ileum that was significantly lower (p < 0.05) under postbiotic supplementation. Both probiotics and postbiotics could be used as a potential growth promoters and might alleviate heat stress impact in poultry industry.

Calculation of Mass Concrete Temperature and Creep Stress under the Influence of Local Air Heat Transfer

Temperature-induced cracking during the construction of mass concrete is a significant concern.Numerical simulations of concrete temperature have primarily assumed that the concrete is placed in an open environment.The problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation boundary.However,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it rises.To accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through experiments.Furthermore,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep stress.The results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete temperature.Compared with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5℃ and 0.7 MPa,respectively,under a wind speed of 4 m/s.The results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/s.However,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.

Daytime Heat Stress, Thermal Pattern, Hyperthermia and Body Caloric Overload in Tropical Acclimatized Holstein and Jersey Heifers

The influence of daytime tropical heat stress in the summer was studied in Holstein and Jersey heifers already acclimatized to tropical environments to determine their physiological response based on body thermal patterns and respiratory alterations according to psychrometric caloric indicators. Daytime psychrometric elements showed a tropical caloric potential for developing moderate to severe heat stress in dairy cattle. Body temperature and respiratory rate increased in both breeds open and pregnant (P < 0.01). Thermal body overload and respiratory works increased from 09 am to 12 md (P < 0.001);reaching and sustaining hyperthermia under the highest caloric pressure from 12 md to 03 pm. Rectal temperature increased +1.5˚C in open Holstein (OH), +1.3˚C in pregnant Holstein (PH), +0.8˚C in open jersey (OJ) and +0.8˚C in pregnant Jersey (PJ). The lowest heat stress index (HSI) was at 06 am, where OH and PH showed a HIS +2.25 and +2.30 and OJ and PJ +2.34 and +2.38. Maximum heat stress occurred at 12 md where OH averaged +3.28 and Pregnant Holsteins showed +3.85 at 03 pm. Open Jersey (OJ) showed a maximum HSI at 12 md (3.54) and PJ resulted in +3.89 at 03 pm. Open and pregnant Jersey heifers were more tolerant to heat stress based on lower body mass, insulation, feed consumption and greater relation between body surface and metabolic body size for thermolysis. Acclimatization between five and twenty-five months under tropical heat stress allowed Holstein and Jersey heifers to develop thermal tolerance. Middle thermal acclimatization lowered thermal sensitivity, hyperthermia and hyperpnea in Holstein and Jersey heifers in the morning;however, pregnant heifers in both breeds showed higher thermal alteration in the afternoon. Tropical acclimatization at low altitudes could be integrated with environmental improvements and nutritional and health management to reduce influences of severe heat stress and improve physiological comfort and welfare in Holstein and Jersey heifers in the summer. Those combined strategies will reduce daytime thermal and respiratory responses and allow growth, pregnancy and health with lower body heat overload and less hyperthermia.

Mechanistic Insights into Ginger’s Role in Improving Sperm Malformation Under Heat Stress Using Network Pharmacology and Molecular Docking

Objective:This study investigates the effects of ginger on sperm dysmorphosis under heat stress using network pharmacology and molecular docking techniques.Methods:The core components,target sites,and primary pathways of ginger were predicted using the TCMSP database.Genes associated with sperm malformation and heat stress were identified through databases such as GeneCards and DisGeNET,followed by KEGG and GO analyses based on intersections with ginger targets.Core genes identified via Cytoscape software were subjected to molecular docking with ginger’s active components.Results:The principal active components of ginger identified includeβ-sitosterol and dihydrocapsaicin.Network pharmacology analysis suggested that ginger exerts its effects through pathways such as the prostate cancer signaling pathway,estrogen signaling pathway,inflammatory pathways,and nuclear receptor signal transduction.These pathways may ameliorate sperm malformation symptoms caused by heat stress.Conclusion:Integrating findings from network pharmacology and molecular docking,the active components of ginger potentially modulate the expression of heat shock proteins during heat stress via inflammatory and oxidative stress pathways.This modulation may protect spermatogenesis under heat stress and improve sperm malformation.

Heat shock transcription factors regulate thermotolerance gene networks in tomato(Solanum lycopersicum)flower buds

Tomato(Solanum lycopersicum)is an important fruit and vegetable crop in worldwide.The fertility of tomato reproductive organs can be dramatically decreased when ambient temperatures rise above 35°C,reducing tomato fruit yield.It is necessary to identify transcription factors(TFs)and target genes involved in heat stress response(HSR)signaling cascades in tomato flower buds to improve tomato plant thermotolerance.In this study,we profiled genes expressed in three developmental stages of tomato flower buds.Red and turquoise modules for heat stress(HS)were identified through gene co-expression network analysis,and the genes within these modules were enriched in HS-related pathways.By focusing on the TFs in the two modules,we identified several novel HSR-related TFs,including SlWRKY75,SlMYB117,and SlNAM.Furthermore,homology analysis illustrated a conserved signaling cascade in tomato.Lastly,we identified and experimentally validated four HSF-regulated genes,namely SlGrpE,SlERDJ3A,SlTIL,and SlPOM1,that likely modulate thermotolerance in plants.These results provide a high-resolution atlas of gene expression during tomato flower bud development under HS conditions,which is a valuable resource for uncovering potential regulatory networks associated with the HSR in tomato.

Breeding for Heat Tolerant Aromatic Rice Varieties and Identification of Novel QTL Regions Associated with Heat Tolerance During Reproductive Phase by QTL-Seq

Extremely high temperatures resulting from climate change have become a major challenge for increasing rice production.Therefore,our objective was to develop heat-tolerant aromatic rice varieties using the pedigree method,focusing on selecting for seed-setting ability under extremely high temperatures along with the use of single nucleotide polymorphism/insertion and deletion(SNP/InDel)markers to improve aromatic properties and grain quality.Furthermore,the QTL-seq approach was utilized to identify QTLs for seed-setting rate in an F2 population subjected to heat stress.The candidate QTL regions were then aligned to confirm SNPs/InDels in synonymous F7 candidate heat-tolerant lines.The results revealed that four promising lines,namely 84-7-1-9,84-7-1-10,159-3-3-1,and 159-3-3-10,were classified as heat-tolerant with low amylose content.In addition,lines 84-7-1-9 and 84-7-1-10 were identified as aromatic rice encompassing the aroma gene(badh2).Regarding the QTL-seq results,the qSF2.1 region ranged from 311051 to 3929422 bp on chromosome 2,was identified based on the highest contrasting SNP index between the heat-susceptible and tolerant bulks.The candidate genes within this region include two genes related to heat shock proteins,three genes associated with pollen fertility,and four genes involved in heat stress and other abiotic stress responses.These genes are proposed as potential candidates for heat tolerance and could serve as targets in rice breeding programs aimed at enhancing heat tolerance.

Effect of heat treatment on stress corrosion cracking, fracture toughness and strength of 7085 aluminum alloy

The influences of heat treatment on stress corrosion cracking （SCC）, fracture toughness and strength of 7085 aluminum alloy were investigated by slow strain rate testing, Kahn tear testing combined with scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the fracture toughness of T74 overaging is increased by 22.9% at the expense of 13.6% strength, and retrogression and reaging （RRA） enhances fracture toughness 14.2% without reducing the strength compared with T6 temper. The fracture toughness of dual-retrogression and reaging （DRRA） is equivalent to that of T74 with an increased strength of 14.6%. The SCC resistance increases in the order： T6〈RRA〈DRRA≈T74. The differences of fracture toughness and SCC were explained on the basis of the role of matrix precipitates and grain boundary orecioitates.

Effects of Traditional Chinese Medicine on Numbers of Lymphocytes and Goblet Cells in Villus Epithelia of Layers under Heat Stress

[Objective] This study aimed to investigate the effects of traditional Chinese medicine additives on numbers of lymphocytes and goblet cells in villus epithelia of layers under heat stress.[Method] A total of 180 88-d-old healthy Esa Brown cocks were selected.They were randomly divided into 9 experimental groups：Room temperature control,High temperature control,VC addition group,High formula I,Moderate formula I,Low formula I,High formula II,Moderate formula II and Low formula II.The formula I and formula II were to add different herbal extracts to the diet of cocks with different doses.The cocks in the VC addition group were administered orally with same-concentration VC solution.After certain time,the cocks were slaughtered.Then the numbers of epithelial lymphocytes and goblet cells in various segments of small intestine were counted by using conventional histological section and HE staining.[Result] The numbers of lymphocytes and goblet cells in villus epithelia of layers under heat stress were decreased gradually with the proceeding of experiment.The herbal extracts of formula I and formula II all could promote the generation of lymphocytes and goblet cells.But the promoting effect of formula II was best.[Conclusion] The Chinese herbal medicine additives have a good relieving effect on heat stress in layers.

Variable chlorophyll fluorescence in response to water plus heat stress treatments in three coniferous tree seedlings

Effects of water and heat stress treatments on chlorophyll fluorescence of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and western redcedar (Thuja plicata D. Don)_seedlings were monitored during a three-cycle stress period. It was shown that ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) of these three species responded differently to water stress treatments. The Fv/Fm ratio of western redcedar decreased dramatically after water stress, while that of Chinese fir had only a slight reduction and that of Masson pine had no significant change. The experiment also showed that the Fv/Fm ratio of all three species differed significantly under heat stress treatments. Concerning three different water plus heat stress cycles, it was found that the Fv/Fm ratios of Chinese fir and Masson pine measured at the end of each water plus heat stress cycle were not significantly different. However, the Fv/Fm ratio of western redcedar was diminished significantly in response to an increase of stress time. Keywords Chinese fir - Chlorophyll fluorescence - Heat stress - Masson pine - Water stress - Western redcedar CLC number Q945.17 - S791.248 Document code A Biography: Yu Fang-yuan (1965-), male, Ph. Doctor. Associate professor in College of Forest Resources and Environment, Nanjing, Forestry University, Nanjing 210037, P. R. China.Responsible editor: Zhu Hong

Regulation of Heat Shock Factor AtHsfA1a on Ascorbate Peroxidase under Heat Stress in Arabidopsis thaliana

[Objective] This study was conducted to investigate the regulation of heat shock factor AtHsfA1a on ascorbate peroxidase under heat stress in Arabidopsis thaliana. [Method] After heat stress treatment on transgenetic A. thaliana with silenced endogenetic AtHsfA1a gene and wild A. thaliana plants as materials, the change in activity of APX enzyme was analyzed by spectrophotometry, the expression level of APX gene was investigated by real-time fluorescent quantitative PCR, and the binding condition of AtHsfAla with the promoter region of APX gene was analyzed by chromatin immunoprecipitation assay. [Result] The activity and mRNA level of APX in plants with silenced endogenetic AtHsfAla gene were higher than those in wild plants. Fragments of the promoter region of APX gene were not screened from the plants with silenced endogenetic AtHsfA1a gene, but found in wild plants. [Conclusion] This study provides a theoretical basis for the understanding of the important role of AtHsfAla in resistance to stress in plant, and is of great significance to the revealing of mechanism of resistance to stress in plant.

Effects of Traditional Chinese Herbal Medicine on the Structure of Duodenal Mucosa of Chickens under Heat Stress

[Objective] This study aimed to investigate the effects of traditional Chinese herbal medicine on the structure of duodenal mucosa of chickens under heat stress. [Method] One hundred and twenty 88-day-old Isa Brown chickens were randomly divided into six groups, including three control groups （normal temperature control group, high temperature control group, high temperature Vc control group） and three high-temperature administration groups （high-dose administration group, moderate-dose administration group, low-dose administration group）. Chickens in normal temperature control group were reared at 14-25 ℃, and those in other five groups were reared at 28-39 ℃. The experiment lasted 10 d. Five chickens in each group were euthanized at 1, 4, 8 and 10 d post-treatment, respectively. The duodenal mucosa was collected and prepared into tissue slices with the conventional method for hematoxylin-eosin （HE） staining. Mucosal thickness, villus length and crypt depth of duodenal mucosa were measured. [Result] Under heat stress, duodenal mucosal thickness and villus length were both significantly lower than those in normal temperature control group, and the duodenal villi were scarce and thin. However, under high temperature conditions, various indicators in high-dose and moderate-dose administration groups were higher than those in high temperature control group and high temperature Vc control group, which exhibited extremely significant differences at 8 and 10 d post-treatment, especially. Moreover, various indicators in high-dose administration group were significantly higher than those in moderate-dose and low-dose administration groups. The traditional Chinese herbal medicine prescription exhibited higher protective effects on duodenal mucosa of chickens under heat stress compared with high temperature Vc control group. [Conclusion] Under heat stress, traditional Chinese herbal medicine reduced effectively the duodenal mucosa damage in chickens.