Mounting evidence supports that a newly identified regulatory T cell (Treg),CD4+LAP+ Treg,is associated with oral tolerance induction and following inhibition of atherosclerosis,but little is described about whether n...Mounting evidence supports that a newly identified regulatory T cell (Treg),CD4+LAP+ Treg,is associated with oral tolerance induction and following inhibition of atherosclerosis,but little is described about whether nasal tolerance to antigen likewise induces the novel Tregs production and the relevant antiatherosclerotic benefit.We investigated the effect of nasal administration of heat shock protein-60 (HSP60) on atherogenesis.HSP60 or phosphate buffer solution (PBS) was nasally adminis-tered to six-week-old male ApoE-/-mice.At the 10th week after the nasal administration,there was a significant decrease in atherosclerotic plaque areas of aortic roots in the HSP60-treated mice as com-pared with those in the PBS-treated mice.Atherosclerosis suppression was accompanied with a signifi-cant increase in CD4+LAP+ and CD4+CD25+Foxp3+ Tregs and a concurrently increased production of TGF-β in the HSP60-treated mice.The protective effect of HSP60 was offset by injection of anti-TGF-βantibody.It is concluded that nasal administration of HSP60 can inhibit atherosclerotic formation through immune tolerance which is established by Tregs depending on the induction of anti-inflammatory cytokine TGF-β.Immune tolerance induced by nasal administration of HSP60 may provide an alternative therapeutic method for atherosclerosis.展开更多
Cold-induced changes of gene expression and metabolism are critical for plants to survive freezing. Largely by changing gene expression, exposure to a period of non-freezing low temperatures increases plant tolerance ...Cold-induced changes of gene expression and metabolism are critical for plants to survive freezing. Largely by changing gene expression, exposure to a period of non-freezing low temperatures increases plant tolerance to freezing--a phenomenon known as cold acclimation. Cold also induces rapid metabolic changes, which provide instant protection before temperature drops below freezing point. The molecular mechanisms for such rapid metabolic responses to cold remain largely unknown. Here, we use two-dimensional difference gel electrophoresis （2-D DIGE） analysis of sub-cellular fractions ofArabidopsis thaliana proteome coupled with spot identification by tandem mass spectrometry to identify early cold-responsive proteins in Arabidopsis. These proteins include four enzymes involved in starch degradation, three HSP100 proteins, several proteins in the tricarboxylic acid cycle, and sucrose metabolism. Upon cold treatment, the Disproportio- nating Enzyme 2 （DPE2）, a cytosolic transglucosidase metabolizing maltose to glucose, increased rapidly in the centrifugation pellet fraction and decreased in the soluble fraction. Consistent with cold-induced inactivation of DPE2 enzymatic activity, the dpe2 mutant showed increased freezing tolerance without affecting the C-repeat binding transcription factor （CBF） transcriptional pathway. These results support a model that cold-induced inactivation of DPE2 leads to rapid accumulation of maltose, which is a cold-induced compatible solute that protects cells from freezing damage. This study provides evidence for a key role of rapid post-translational regulation of carbohydrate metabolic enzymes in plant protection against sudden temperature drop.展开更多
Cross tolerance, whereby tolerance to one environmental stress is correlated with tolerance to other stressors, is thought to be widespread in insects. We used lines of Drosophila melanogaster Meigen （Diptera： Droso...Cross tolerance, whereby tolerance to one environmental stress is correlated with tolerance to other stressors, is thought to be widespread in insects. We used lines of Drosophila melanogaster Meigen （Diptera： Drosophilidae） selected for survival at a 1-h exposure to -5℃ to examine the extent to which this selection results in increased tolerance to other stresses, including high and low temperatures, desiccation and starvation. While selection improved tolerance to acute cold exposure and survival at -5℃, there was little effect of selection regime on tolerance to other stressors. There was no correlation between tolerances to any of the stressors, suggesting different mechanisms of tolerance. This supports arguments that correlations between stress tolerances during selection experiments with D. melanogaster may be coincidental. The magnitude of heat-hardening was apparently constrained by basal tolerance among lines, but the magnitude of the rapid cold-hardening response was not correlated with basal cold tolerance, implying that the relationship between inducible and basal tolerances differs at high and low temperatures.展开更多
Temperature sensitivity and tolerance play a key role in plant survival and production.Perennial ryegrass(Lolium perenne L.),widely cultivated in cool-season for forage supply and turfgrass,is extremely susceptible to...Temperature sensitivity and tolerance play a key role in plant survival and production.Perennial ryegrass(Lolium perenne L.),widely cultivated in cool-season for forage supply and turfgrass,is extremely susceptible to high temperatures,therefore serving as an excellent grass for dissecting the genomic and genetic basis of high-temperature adaptation.In this study,expression analysis revealed that LpHsfA2,an important gene associated with high-temperature tolerance in perennial ryegrass,is rapidly and substantially induced under heat stress.Additionally,heat-tolerant varieties consistently display elevated expression levels of LpHsfA2 compared with heat-sensitive ones.Comparative haplotype analysis of the LpHsfA2 promoter indicated an uneven distribution of two haplotypes(HsfA2^(Hap1) and HsfA2^(Hap2)) across varieties with differing heat tolerance.Specifically,the HsfA2^(Hap1) allele is predominantly present in heat-tolerant varieties,while the HsfA2^(Hap2) allele exhibits the opposite pattern.Overexpression of LpHsfA2 confers enhanced thermotolerance,whereas silencing of LpHsfA2 compromises heat tolerance.Furthermore,LpHsfA2 orchestrates its protective effects by directly binding to the promoters of LpHSP18.2 and LpAPX1 to activate their expression,preventing the non-specific misfolding of intracellular protein and the accumulation of reactive oxygen species in cells.Additionally,LpHsf A4 and LpHsf A5 were shown to engage directly with the promoter of LpHsfA2,upregulating its expression as well as the expression of LpHSP18.2 and LpAPX1,thus contributing to enhanced heat tolerance.Markedly,LpHsfA2 possesses autoregulatory ability by directly binding to its own promoter to modulate the self-transcription.Based on these findings,we propose a model for modulating the thermotolerance of perennial ryegrass by precisely regulating the expression of LpHsfA2.Collectively,these findings provide a scientific basis for the development of thermotolerant perennial ryegrass cultivars.展开更多
Understanding how maize(Zea mays)responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties.Despite extensive utilization of the genome-wide association study(GWAs)approach for ex...Understanding how maize(Zea mays)responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties.Despite extensive utilization of the genome-wide association study(GWAs)approach for exploring favorable natural alleles associated with maize cold tolerance,few studies have successfully identified candidate genes that contribute to maize cold tolerance.In this study,we used a diverse panel of inbred maize lines collected from different germplasm sources to perform a GWAS on var-iations in the relative injured area of maize true leaves during cold stress-a trait very closely correlated with maize cold tolerance.We identified HsF21,which encodes a B-class heat shock transcription factor(HSF)that positively regulates cold tolerance at both the seedling and germination stages.Natural varia-tions in the promoter of the cold-tolerant HSF21Hap1 allele led to increased HSF21 expression under cold stress by inhibiting binding of the basic leucine zipper bziP68 transcription factor,a negative regulator of cold tolerance.By integrating transcriptome deep sequencing,DNA affinity purification sequencing,and targeted lipidomic analysis,we revealed the function of HsF21 in regulating lipid metabolism homeo-stasis to modulate cold tolerance in maize.In addition,we found that HsF21 confers maize cold tolerance without incurring yield penalties.Collectively,this study establishes HsF21 as a key regulator that en-hances cold tolerance in maize,providing valuable genetic resources for breeding of cold-tolerant maize varieties.展开更多
We used a proteomic approach to identify IbpA in Cronobacter sakazokii （C. sakazaki）, which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat sh...We used a proteomic approach to identify IbpA in Cronobacter sakazokii （C. sakazaki）, which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat shock. C sakazakii CMCC 45402 ibpA deletion mutants were successfully constructed. The C. sakazakii CMCC 45402 AibpA and wild-type strains could not be distinguished based on colony morphology on LB agar plates or biochemical assays. The growth of the C. sakazakii CMCC 45402 AibpA mutant in heat shock conditions was indistinguishable from that of the isogenic wild-type, but showed greater heat resistance than E. coil O157：H7 strain CMCC 44828. This study suggests that the absence of a single ibpA gene has no obvious effect on the phenotype or heat resistance of the strain C. sakazakii CMCC 45402.展开更多
Cold shock domain(CSD)-containing proteins are one of the groups of the evolutionarily conserved nucleic acid-binding proteins in all three domains of life consisting of an ancient beta-barrel fold that serves to bind...Cold shock domain(CSD)-containing proteins are one of the groups of the evolutionarily conserved nucleic acid-binding proteins in all three domains of life consisting of an ancient beta-barrel fold that serves to bind nucleic acids.The c DNA of a novel protein-coding gene containing CSD was cloned from Glaciozyma antarctica designated as Ga16676.The full length of Ga16676 gene with the size of 1335 bp encodes for an N-terminal CSD with conserved nucleic acids binding motif RNP1 and RNP2.The Ga16676 gene was cloned in p ET30 Ek/LIC,sequenced,expressed and its resistance towards cold was characterized.Recombinant protein expression of Ga16676 showed overexpressed soluble expression in both supernatant and pellet forms at 20℃.The effects of recombinant CSD protein overexpression on colony formation shows that E.coli cells were able to grow at 37℃and 20℃but not at 4℃while E.coli_Ga16676 cells were able to grow at all temperatures tested.In addition,E.coli_Ga16676 cells showed higher growth rate compared to empty E.coli cells at 10℃.Structural analysis of Ga16676 reveals some interesting findings such as more aromatic interactions for efficient binding in low energy environment,a longer loop that may contribute to structural flexibility and clustering of charged amino acids on the protein surface that is important for protein stability and flexibility.展开更多
文摘Mounting evidence supports that a newly identified regulatory T cell (Treg),CD4+LAP+ Treg,is associated with oral tolerance induction and following inhibition of atherosclerosis,but little is described about whether nasal tolerance to antigen likewise induces the novel Tregs production and the relevant antiatherosclerotic benefit.We investigated the effect of nasal administration of heat shock protein-60 (HSP60) on atherogenesis.HSP60 or phosphate buffer solution (PBS) was nasally adminis-tered to six-week-old male ApoE-/-mice.At the 10th week after the nasal administration,there was a significant decrease in atherosclerotic plaque areas of aortic roots in the HSP60-treated mice as com-pared with those in the PBS-treated mice.Atherosclerosis suppression was accompanied with a signifi-cant increase in CD4+LAP+ and CD4+CD25+Foxp3+ Tregs and a concurrently increased production of TGF-β in the HSP60-treated mice.The protective effect of HSP60 was offset by injection of anti-TGF-βantibody.It is concluded that nasal administration of HSP60 can inhibit atherosclerotic formation through immune tolerance which is established by Tregs depending on the induction of anti-inflammatory cytokine TGF-β.Immune tolerance induced by nasal administration of HSP60 may provide an alternative therapeutic method for atherosclerosis.
文摘Cold-induced changes of gene expression and metabolism are critical for plants to survive freezing. Largely by changing gene expression, exposure to a period of non-freezing low temperatures increases plant tolerance to freezing--a phenomenon known as cold acclimation. Cold also induces rapid metabolic changes, which provide instant protection before temperature drops below freezing point. The molecular mechanisms for such rapid metabolic responses to cold remain largely unknown. Here, we use two-dimensional difference gel electrophoresis （2-D DIGE） analysis of sub-cellular fractions ofArabidopsis thaliana proteome coupled with spot identification by tandem mass spectrometry to identify early cold-responsive proteins in Arabidopsis. These proteins include four enzymes involved in starch degradation, three HSP100 proteins, several proteins in the tricarboxylic acid cycle, and sucrose metabolism. Upon cold treatment, the Disproportio- nating Enzyme 2 （DPE2）, a cytosolic transglucosidase metabolizing maltose to glucose, increased rapidly in the centrifugation pellet fraction and decreased in the soluble fraction. Consistent with cold-induced inactivation of DPE2 enzymatic activity, the dpe2 mutant showed increased freezing tolerance without affecting the C-repeat binding transcription factor （CBF） transcriptional pathway. These results support a model that cold-induced inactivation of DPE2 leads to rapid accumulation of maltose, which is a cold-induced compatible solute that protects cells from freezing damage. This study provides evidence for a key role of rapid post-translational regulation of carbohydrate metabolic enzymes in plant protection against sudden temperature drop.
文摘Cross tolerance, whereby tolerance to one environmental stress is correlated with tolerance to other stressors, is thought to be widespread in insects. We used lines of Drosophila melanogaster Meigen （Diptera： Drosophilidae） selected for survival at a 1-h exposure to -5℃ to examine the extent to which this selection results in increased tolerance to other stresses, including high and low temperatures, desiccation and starvation. While selection improved tolerance to acute cold exposure and survival at -5℃, there was little effect of selection regime on tolerance to other stressors. There was no correlation between tolerances to any of the stressors, suggesting different mechanisms of tolerance. This supports arguments that correlations between stress tolerances during selection experiments with D. melanogaster may be coincidental. The magnitude of heat-hardening was apparently constrained by basal tolerance among lines, but the magnitude of the rapid cold-hardening response was not correlated with basal cold tolerance, implying that the relationship between inducible and basal tolerances differs at high and low temperatures.
基金supported by the National Key R&D Program of China(2022YFF1003200)the National Natural Science Foundation of China(NSFC)(Grant Nos.32001394,32102431 and 32101430)+2 种基金the Science&Technology Specific Projects in Agricultural High-tech Industrial Demonstration Area of the Yellow River Delta(Grant No.2022SZX13)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA26050201)the Major Science and Technology Innovation Project of Shandong Province(2022LZGC018)。
文摘Temperature sensitivity and tolerance play a key role in plant survival and production.Perennial ryegrass(Lolium perenne L.),widely cultivated in cool-season for forage supply and turfgrass,is extremely susceptible to high temperatures,therefore serving as an excellent grass for dissecting the genomic and genetic basis of high-temperature adaptation.In this study,expression analysis revealed that LpHsfA2,an important gene associated with high-temperature tolerance in perennial ryegrass,is rapidly and substantially induced under heat stress.Additionally,heat-tolerant varieties consistently display elevated expression levels of LpHsfA2 compared with heat-sensitive ones.Comparative haplotype analysis of the LpHsfA2 promoter indicated an uneven distribution of two haplotypes(HsfA2^(Hap1) and HsfA2^(Hap2)) across varieties with differing heat tolerance.Specifically,the HsfA2^(Hap1) allele is predominantly present in heat-tolerant varieties,while the HsfA2^(Hap2) allele exhibits the opposite pattern.Overexpression of LpHsfA2 confers enhanced thermotolerance,whereas silencing of LpHsfA2 compromises heat tolerance.Furthermore,LpHsfA2 orchestrates its protective effects by directly binding to the promoters of LpHSP18.2 and LpAPX1 to activate their expression,preventing the non-specific misfolding of intracellular protein and the accumulation of reactive oxygen species in cells.Additionally,LpHsf A4 and LpHsf A5 were shown to engage directly with the promoter of LpHsfA2,upregulating its expression as well as the expression of LpHSP18.2 and LpAPX1,thus contributing to enhanced heat tolerance.Markedly,LpHsfA2 possesses autoregulatory ability by directly binding to its own promoter to modulate the self-transcription.Based on these findings,we propose a model for modulating the thermotolerance of perennial ryegrass by precisely regulating the expression of LpHsfA2.Collectively,these findings provide a scientific basis for the development of thermotolerant perennial ryegrass cultivars.
基金supported by Biological Breeding-National Science and Technology Major Project of China(2023ZD0407104)the National Natural Science Foundation of China(32272025 and 31730011)the Pinduoduo-China Agricultural University Research Fund(PC2023B01001),and the Chinese Universities Scientific Fund.
文摘Understanding how maize(Zea mays)responds to cold stress is crucial for facilitating breeding programs of cold-tolerant varieties.Despite extensive utilization of the genome-wide association study(GWAs)approach for exploring favorable natural alleles associated with maize cold tolerance,few studies have successfully identified candidate genes that contribute to maize cold tolerance.In this study,we used a diverse panel of inbred maize lines collected from different germplasm sources to perform a GWAS on var-iations in the relative injured area of maize true leaves during cold stress-a trait very closely correlated with maize cold tolerance.We identified HsF21,which encodes a B-class heat shock transcription factor(HSF)that positively regulates cold tolerance at both the seedling and germination stages.Natural varia-tions in the promoter of the cold-tolerant HSF21Hap1 allele led to increased HSF21 expression under cold stress by inhibiting binding of the basic leucine zipper bziP68 transcription factor,a negative regulator of cold tolerance.By integrating transcriptome deep sequencing,DNA affinity purification sequencing,and targeted lipidomic analysis,we revealed the function of HsF21 in regulating lipid metabolism homeo-stasis to modulate cold tolerance in maize.In addition,we found that HsF21 confers maize cold tolerance without incurring yield penalties.Collectively,this study establishes HsF21 as a key regulator that en-hances cold tolerance in maize,providing valuable genetic resources for breeding of cold-tolerant maize varieties.
基金funded by National Science and Technology Major Project of the Ministry of Science and Technology of China(2013ZX09304101)
文摘We used a proteomic approach to identify IbpA in Cronobacter sakazokii （C. sakazaki）, which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat shock. C sakazakii CMCC 45402 ibpA deletion mutants were successfully constructed. The C. sakazakii CMCC 45402 AibpA and wild-type strains could not be distinguished based on colony morphology on LB agar plates or biochemical assays. The growth of the C. sakazakii CMCC 45402 AibpA mutant in heat shock conditions was indistinguishable from that of the isogenic wild-type, but showed greater heat resistance than E. coil O157：H7 strain CMCC 44828. This study suggests that the absence of a single ibpA gene has no obvious effect on the phenotype or heat resistance of the strain C. sakazakii CMCC 45402.
基金the Ministry of Higher Education Malaysia for funding our project(Grant no.FRG0463-2017)。
文摘Cold shock domain(CSD)-containing proteins are one of the groups of the evolutionarily conserved nucleic acid-binding proteins in all three domains of life consisting of an ancient beta-barrel fold that serves to bind nucleic acids.The c DNA of a novel protein-coding gene containing CSD was cloned from Glaciozyma antarctica designated as Ga16676.The full length of Ga16676 gene with the size of 1335 bp encodes for an N-terminal CSD with conserved nucleic acids binding motif RNP1 and RNP2.The Ga16676 gene was cloned in p ET30 Ek/LIC,sequenced,expressed and its resistance towards cold was characterized.Recombinant protein expression of Ga16676 showed overexpressed soluble expression in both supernatant and pellet forms at 20℃.The effects of recombinant CSD protein overexpression on colony formation shows that E.coli cells were able to grow at 37℃and 20℃but not at 4℃while E.coli_Ga16676 cells were able to grow at all temperatures tested.In addition,E.coli_Ga16676 cells showed higher growth rate compared to empty E.coli cells at 10℃.Structural analysis of Ga16676 reveals some interesting findings such as more aromatic interactions for efficient binding in low energy environment,a longer loop that may contribute to structural flexibility and clustering of charged amino acids on the protein surface that is important for protein stability and flexibility.
