The importance of NAC(named as NAM,ATAF1,2,and CUC2)proteins in plant development,transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized.We report here ...The importance of NAC(named as NAM,ATAF1,2,and CUC2)proteins in plant development,transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized.We report here the high resolution crystal structure of SNAC1(stress-responsive NAC)NAC domain at 2.5Å.Although the structure of the SNAC1 NAC domain shares a structural similarity with the reported structure of the ANAC NAC1 domain,some key features,especially relating to two loop regions which potentially take the responsibility for DNA-binding,distinguish the SNAC1 NAC domain from other reported NAC structures.Moreover,the dimerization of the SNAC1 NAC domain is demonstrated by both soluble and crystalline conditions,suggesting this dimeric state should be conserved in this type of NAC family.Additionally,we discuss the possible NAC-DNA binding model according to the structure and reported biological evidences.展开更多
Prokaryotic gene expression is largely regulated on transcriptional levels with the involvement of promoters,RNA polymerase and sigma factors.Developing new promoters to customize gene transcriptional regulation becom...Prokaryotic gene expression is largely regulated on transcriptional levels with the involvement of promoters,RNA polymerase and sigma factors.Developing new promoters to customize gene transcriptional regulation becomes increasingly demanded in synthetic biology and biotechnology.In this study,we designed synthetic promoters in the Gram-positive model bacterium Bacillus subtilis by interlocking the binding motifs ofσA for house-keeping gene expression and that of two alternative sigma factorsσH andσB which are involved in responding post-exponential growth and general stress,respectively.The developed promoters are recognized by multiple sigma factors and hence generate strong transcriptional strength when host cells grow under normal or stressed conditions.With green fluorescent protein as the reporter,a set of strong promoters were identified,in which the transcription activities of PHA-1,PHAB-4,PHAB-7 were 18.6,4.1,3.3 fold of that of the commonly used promoter P43,respectively.Moreover,some of the promoters such as PHA-1,PHAB-4,PHAB-7,PBA-2 displayed increased transcriptional activities in response to high salinity or low pH.The promoters developed in this study should enrich the biotechnological toolboxes of B.subtilis.展开更多
Phosphorus(P)is an essential macronutrient required for plant growth,development,and resilience to environmental stresses.Its availability in soil and homeostasis within plants are strongly influenced by environmental...Phosphorus(P)is an essential macronutrient required for plant growth,development,and resilience to environmental stresses.Its availability in soil and homeostasis within plants are strongly influenced by environmental conditions,with unfavorable environments and soil factors disrupting phosphate availability,absorption,transport,and utilization.Optimizing phosphate supply can alleviate the detrimental impacts of abiotic stresses,thereby supporting growth and improving stress tolerance.Recent studies reveal that abiotic stresses modulate phosphate signaling pathways and alter the expression of phosphate-responsive genes,often affecting key regulators of P homeostasis.Strategic manipulation of phosphate transporters and their regulatory pathways offers a promising approach to enhance plant adaptation to challenging environments.This review highlights current advances in understanding the molecular mechanisms that coordinate P-responsive gene expression and homeostasis pathways under fluctuating P availability and stress conditions.It emphasizes the critical role of P nutrition in enhancing plant stress tolerance through antioxidant activation,osmolyte accumulation,membrane stabilization,and metal-phosphate complex formation.An in-depth mechanistic understanding of P-stress interactions will inform the development of P-efficient and stress-resistant crop varieties and guide more sustainable P fertilizer management in agriculture.展开更多
Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis tha...Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.展开更多
Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils.Quinoa,a protein-comprehensive cereal in the plant kingdom,is an ex...Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils.Quinoa,a protein-comprehensive cereal in the plant kingdom,is an exceptional crop in terms of salt stress tolerance level.It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms.In this study,the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution.The physiological,biochemical characteristics and agronomic traits were investigated,and the response patterns of three salt stress-responsive genes(SSRGs)in quinoa were determined by real-time PCR.The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl.Salt stress significantly induced expression of superoxide dismutase(SOD),peroxidase(POD),and particularly betaine aldehyde dehydrogenase(BADH).BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings,particularly at high NaCl concentrations,as it displayed upregulation until 24 h under 100 mM salt treatment.Moreover,it showed upregulation until 12 h under 250 mM salt stress.Taken together,these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa.Based on the expression level and prompt response induced by NaCl,we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development.Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth.Therefore,an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm,which is useful to the utilization of saline soils.Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.展开更多
This paper presents the end Late Paleozoic tectonic stress field in the southern edge of Junggar Basin by interpreting stress-response structures （dykes, folds, faults with slickenside and conjugate joints）. The dir...This paper presents the end Late Paleozoic tectonic stress field in the southern edge of Junggar Basin by interpreting stress-response structures （dykes, folds, faults with slickenside and conjugate joints）. The direction of the maximum principal stress axes is interpreted to be NW-SE （about 325°）, and the accommodated motion among plates is assigned as the driving force of this tectonic stress field. The average value of the stress index Rt is about 2.09, which indicates a variation from strike-slip to compressive tectonic stress regime in the study area during the end Late Paleozoic period. The reconstruction of the tectonic field in the southern edge of Junggar Basin provides insights into the tectonic deformation processes around the southern Junggar Basin and contributes to the further understanding of basin evolution and tectonic settings during the culmination of the Paleo- zoic.展开更多
Alzheimer’s disease is a neurodegenerative disorder characterized by progressive cognitive impairment and neuropathology. Recent preclinical and epidemiological studies proposed statins as a possible therapeutic drug...Alzheimer’s disease is a neurodegenerative disorder characterized by progressive cognitive impairment and neuropathology. Recent preclinical and epidemiological studies proposed statins as a possible therapeutic drug for Alzheimer’s disease, but the exact mechanisms of action are still unknown. Biliverdin reductase-A is a pleiotropic enzyme involved in cellular stress responses. It not only transforms biliverdin-IX alpha into the antioxidant bilirubin-IX alpha but its serine/threonine/ tyrosine kinase activity is able to modulate cell signaling networks. We previously reported the beneficial effects of atorvastatin treatment on biliverdin reductase-A and heme oxygenase-1 in the brains of a well characterized pre-clinical model of Alzheimer’s disease, aged beagles, together with observed improvement in cognition. Here we extend our knowledge of the effects of atorvastatin on inducible nitric oxide synthase in parietal cortex, cerebellum and liver of the same animals. We demonstrated that atorvastatin treatment （80 mg/day for 14.5 months） to aged beagles selectively increased inducible nitric oxide synthase in the parietal cortex but not in the cerebellum. In contrast, inducible nitric oxide synthase protein levels were significantly decreased in the liver. Significant positive correlations were found between biliverdin reductase-A and inducible nitric oxide synthase as well as heme oxygenase-1 protein levels in the parietal cortex. The opposite was observed in the liver. Inducible nitric oxide synthase up-regulation in the parietal cortex was positively associated with improved biliverdin reductase-A functions, whereas the oxidative-induced impairment of biliverdin reductase-A in the liver negatively affected inducible nitric oxide synthase expression, thus suggesting a role for biliverdin reductase-A in atorvastatin-dependent inducible nitric oxide synthase changes. Interestingly, increased inducible nitric oxide synthase levels in the parietal cortex were not associated with higher oxidative/nitrosative stress levels. We hypothesize that biliverdin reductase-A-dependent inducible nitric oxide synthase regulation strongly contributes to the cognitive improvement observed following atorvastatin treatment.展开更多
Quantitative trait loci (QTLs) mapping has been performed during the past decades in an attempt to identify genes, gene products and mechanisms underlying numerous quantitative traits. It’s a strategy based on natura...Quantitative trait loci (QTLs) mapping has been performed during the past decades in an attempt to identify genes, gene products and mechanisms underlying numerous quantitative traits. It’s a strategy based on natural variations in genes and gene products, which facilitates translation from animal models to human clinical conditions. Our team has shown that the inbred rat strains Lewis (LEW) and Spontaneously Hypertensive Rats (SHR) differ with respect to several emotionality- related behaviors, one of which (inner locomotion in the open field) was strongly influenced by a QTL (Anxrr16) on rat chromosome 4. Since then, several other studies not only corroborated the initial description of Anxrr16, but also extrapolated its effects to a broader context (rats from both sexes and regardless of the estrous cycle phase) and suggested that this same region influences other emotionality-related behaviors as well as alcohol intake. Other QTLs affecting neurobiological traits were also found on rat chromosome 4 and several candidate genes have been pointed out as possibly influencing those phenotypes. Altogether, these studies suggest that rat chromosome 4 constitutes an interesting target for the study of the molecular bases of anxiety and other traits related to emotional reactivity.展开更多
Pre-exposure to a stress may alter the plant＇s cellular, biochemical, and/or transcriptional responses during future encounters as a ＂memory＇ from the previous stress. Genes increasing transcription in response to ...Pre-exposure to a stress may alter the plant＇s cellular, biochemical, and/or transcriptional responses during future encounters as a ＂memory＇ from the previous stress. Genes increasing transcription in response to a first dehydra- tion stress, but producing much higher transcript levels in a subsequent stress, represent the super-induced ＇transcription memory＇ genes in Arabidopsis thaliana. The chromatin environment （histone H3 tri-methylations of Lys 4 and Lys 27, H3K4me3, and H3K27me3） studied at five dehydration stress memory genes revealed existence of distinct memory- response subclasses that responded differently to CLF deficiency and displayed different transcriptional activities dur- ing the watered recovery periods. Among the most important findings is the novel aspect of the H3K27me3 function observed at specific dehydration stress memory genes. In contrast to its well-known role as a chromatin repressive mechanism at developmentally regulated genes, H3K27me3 did not prevent transcription from the dehydration stress- responding genes. The high H3K27me3 levels present during transcriptionally inactive states did not interfere with the transition to active transcription and with H3K4me3 accumulation. H3K4me3 and H3K27me3 marks function indepen- dently and are not mutually exclusive at the dehydration stress-responding memory genes.展开更多
In the probiotics manufacturing process,lyophilization damages the cell membrane of microorganisms,reducing their viability and delaying reactivation of their cellular metabolism.The growth phase of microorganisms at ...In the probiotics manufacturing process,lyophilization damages the cell membrane of microorganisms,reducing their viability and delaying reactivation of their cellular metabolism.The growth phase of microorganisms at the time of lyophilization is thought to significantly affect their viability during storage and reactivation in the intestine.However,no study has systematically investigated the differences in overcoming mechanisms in microorganisms harvested at different growth phases against lyophilization.Therefore,in this study,we comparatively assessed the resistance mechanism of Bifidobacterium animalis ssp.lactis and Lacticaseibacillus rhamnosus harvested at exponential and stationary growth phases.We found that B.animalis ssp.lactis and L.rhamnosus harvested at the stationary phase had shorter lag phase in growth and higher survival rates during storage than those harvested at the exponential phase.As a result of metabolome analysis,the cells harvested at the stationary phase accumulated trehalose and arabinose,which function as cryoprotectants and protect cells from lyophilization-induced damage.These findings could provide a basis for establishing a manufacturing protocol for lyophilized probiotics that can be rapidly reactivated in the intestine to achieve optimal metabolic activity and induce health benefits.展开更多
基金the National Natural Science Foundation of China(Grant Nos.30730022 and 30870486)the National Basic Research Program(973 Program)(Grant No.2007CB914304)the National Major Projects(grant Nos.2009ZX09311-001 and 2009ZX10004-304).
文摘The importance of NAC(named as NAM,ATAF1,2,and CUC2)proteins in plant development,transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized.We report here the high resolution crystal structure of SNAC1(stress-responsive NAC)NAC domain at 2.5Å.Although the structure of the SNAC1 NAC domain shares a structural similarity with the reported structure of the ANAC NAC1 domain,some key features,especially relating to two loop regions which potentially take the responsibility for DNA-binding,distinguish the SNAC1 NAC domain from other reported NAC structures.Moreover,the dimerization of the SNAC1 NAC domain is demonstrated by both soluble and crystalline conditions,suggesting this dimeric state should be conserved in this type of NAC family.Additionally,we discuss the possible NAC-DNA binding model according to the structure and reported biological evidences.
基金This work was financially supported by the National Natural Science Foundation of China(31970085 and 31670092)the National Key R&D program of China(2018YFA0901401)+2 种基金the Fundamental Research Funds for the Central Universities(JUSRP51707A)a grant from the Key Technologies R&D Program of Jiangsu Province(BE2019630)the 111 Project.Y.W.was sponsored by the China Postdoctoral Science Foundation(2019M651702).
文摘Prokaryotic gene expression is largely regulated on transcriptional levels with the involvement of promoters,RNA polymerase and sigma factors.Developing new promoters to customize gene transcriptional regulation becomes increasingly demanded in synthetic biology and biotechnology.In this study,we designed synthetic promoters in the Gram-positive model bacterium Bacillus subtilis by interlocking the binding motifs ofσA for house-keeping gene expression and that of two alternative sigma factorsσH andσB which are involved in responding post-exponential growth and general stress,respectively.The developed promoters are recognized by multiple sigma factors and hence generate strong transcriptional strength when host cells grow under normal or stressed conditions.With green fluorescent protein as the reporter,a set of strong promoters were identified,in which the transcription activities of PHA-1,PHAB-4,PHAB-7 were 18.6,4.1,3.3 fold of that of the commonly used promoter P43,respectively.Moreover,some of the promoters such as PHA-1,PHAB-4,PHAB-7,PBA-2 displayed increased transcriptional activities in response to high salinity or low pH.The promoters developed in this study should enrich the biotechnological toolboxes of B.subtilis.
基金supported by the National Natural Science Foundation of China(32372802).
文摘Phosphorus(P)is an essential macronutrient required for plant growth,development,and resilience to environmental stresses.Its availability in soil and homeostasis within plants are strongly influenced by environmental conditions,with unfavorable environments and soil factors disrupting phosphate availability,absorption,transport,and utilization.Optimizing phosphate supply can alleviate the detrimental impacts of abiotic stresses,thereby supporting growth and improving stress tolerance.Recent studies reveal that abiotic stresses modulate phosphate signaling pathways and alter the expression of phosphate-responsive genes,often affecting key regulators of P homeostasis.Strategic manipulation of phosphate transporters and their regulatory pathways offers a promising approach to enhance plant adaptation to challenging environments.This review highlights current advances in understanding the molecular mechanisms that coordinate P-responsive gene expression and homeostasis pathways under fluctuating P availability and stress conditions.It emphasizes the critical role of P nutrition in enhancing plant stress tolerance through antioxidant activation,osmolyte accumulation,membrane stabilization,and metal-phosphate complex formation.An in-depth mechanistic understanding of P-stress interactions will inform the development of P-efficient and stress-resistant crop varieties and guide more sustainable P fertilizer management in agriculture.
文摘Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.
基金supported jointly by the Public Project of Science Technology Department of Zhejiang Province(Grant No.2016C02050-9-9)to Y.Jiang and the Zhejiang Provincial Natural Science Foundation of China(Grant No.Y21C130006)to Y.Jiang,and the Key Research and Development Project of Zhejiang Province(Grant No.2021C02057)to G.Luo.
文摘Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils.Quinoa,a protein-comprehensive cereal in the plant kingdom,is an exceptional crop in terms of salt stress tolerance level.It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms.In this study,the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution.The physiological,biochemical characteristics and agronomic traits were investigated,and the response patterns of three salt stress-responsive genes(SSRGs)in quinoa were determined by real-time PCR.The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl.Salt stress significantly induced expression of superoxide dismutase(SOD),peroxidase(POD),and particularly betaine aldehyde dehydrogenase(BADH).BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings,particularly at high NaCl concentrations,as it displayed upregulation until 24 h under 100 mM salt treatment.Moreover,it showed upregulation until 12 h under 250 mM salt stress.Taken together,these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa.Based on the expression level and prompt response induced by NaCl,we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development.Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth.Therefore,an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm,which is useful to the utilization of saline soils.Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.
基金supported by the National Natural Science Foundation of China Grant(Nos.40772121,40314141 and 40172066)China National Project 973(No.2009CB219302)
文摘This paper presents the end Late Paleozoic tectonic stress field in the southern edge of Junggar Basin by interpreting stress-response structures （dykes, folds, faults with slickenside and conjugate joints）. The direction of the maximum principal stress axes is interpreted to be NW-SE （about 325°）, and the accommodated motion among plates is assigned as the driving force of this tectonic stress field. The average value of the stress index Rt is about 2.09, which indicates a variation from strike-slip to compressive tectonic stress regime in the study area during the end Late Paleozoic period. The reconstruction of the tectonic field in the southern edge of Junggar Basin provides insights into the tectonic deformation processes around the southern Junggar Basin and contributes to the further understanding of basin evolution and tectonic settings during the culmination of the Paleo- zoic.
基金Funding for the canine atorvastatin study was through the Alzheimer's Association IIRG-03-5673 to Elizabeth Head
文摘Alzheimer’s disease is a neurodegenerative disorder characterized by progressive cognitive impairment and neuropathology. Recent preclinical and epidemiological studies proposed statins as a possible therapeutic drug for Alzheimer’s disease, but the exact mechanisms of action are still unknown. Biliverdin reductase-A is a pleiotropic enzyme involved in cellular stress responses. It not only transforms biliverdin-IX alpha into the antioxidant bilirubin-IX alpha but its serine/threonine/ tyrosine kinase activity is able to modulate cell signaling networks. We previously reported the beneficial effects of atorvastatin treatment on biliverdin reductase-A and heme oxygenase-1 in the brains of a well characterized pre-clinical model of Alzheimer’s disease, aged beagles, together with observed improvement in cognition. Here we extend our knowledge of the effects of atorvastatin on inducible nitric oxide synthase in parietal cortex, cerebellum and liver of the same animals. We demonstrated that atorvastatin treatment （80 mg/day for 14.5 months） to aged beagles selectively increased inducible nitric oxide synthase in the parietal cortex but not in the cerebellum. In contrast, inducible nitric oxide synthase protein levels were significantly decreased in the liver. Significant positive correlations were found between biliverdin reductase-A and inducible nitric oxide synthase as well as heme oxygenase-1 protein levels in the parietal cortex. The opposite was observed in the liver. Inducible nitric oxide synthase up-regulation in the parietal cortex was positively associated with improved biliverdin reductase-A functions, whereas the oxidative-induced impairment of biliverdin reductase-A in the liver negatively affected inducible nitric oxide synthase expression, thus suggesting a role for biliverdin reductase-A in atorvastatin-dependent inducible nitric oxide synthase changes. Interestingly, increased inducible nitric oxide synthase levels in the parietal cortex were not associated with higher oxidative/nitrosative stress levels. We hypothesize that biliverdin reductase-A-dependent inducible nitric oxide synthase regulation strongly contributes to the cognitive improvement observed following atorvastatin treatment.
文摘Quantitative trait loci (QTLs) mapping has been performed during the past decades in an attempt to identify genes, gene products and mechanisms underlying numerous quantitative traits. It’s a strategy based on natural variations in genes and gene products, which facilitates translation from animal models to human clinical conditions. Our team has shown that the inbred rat strains Lewis (LEW) and Spontaneously Hypertensive Rats (SHR) differ with respect to several emotionality- related behaviors, one of which (inner locomotion in the open field) was strongly influenced by a QTL (Anxrr16) on rat chromosome 4. Since then, several other studies not only corroborated the initial description of Anxrr16, but also extrapolated its effects to a broader context (rats from both sexes and regardless of the estrous cycle phase) and suggested that this same region influences other emotionality-related behaviors as well as alcohol intake. Other QTLs affecting neurobiological traits were also found on rat chromosome 4 and several candidate genes have been pointed out as possibly influencing those phenotypes. Altogether, these studies suggest that rat chromosome 4 constitutes an interesting target for the study of the molecular bases of anxiety and other traits related to emotional reactivity.
文摘Pre-exposure to a stress may alter the plant＇s cellular, biochemical, and/or transcriptional responses during future encounters as a ＂memory＇ from the previous stress. Genes increasing transcription in response to a first dehydra- tion stress, but producing much higher transcript levels in a subsequent stress, represent the super-induced ＇transcription memory＇ genes in Arabidopsis thaliana. The chromatin environment （histone H3 tri-methylations of Lys 4 and Lys 27, H3K4me3, and H3K27me3） studied at five dehydration stress memory genes revealed existence of distinct memory- response subclasses that responded differently to CLF deficiency and displayed different transcriptional activities dur- ing the watered recovery periods. Among the most important findings is the novel aspect of the H3K27me3 function observed at specific dehydration stress memory genes. In contrast to its well-known role as a chromatin repressive mechanism at developmentally regulated genes, H3K27me3 did not prevent transcription from the dehydration stress- responding genes. The high H3K27me3 levels present during transcriptionally inactive states did not interfere with the transition to active transcription and with H3K4me3 accumulation. H3K4me3 and H3K27me3 marks function indepen- dently and are not mutually exclusive at the dehydration stress-responding memory genes.
基金supported by a National Research Foundation of Korea Grant,funded by the Korean government(MEST)(NRF-2021R1A2C3011051)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2022M3A9I5018286).
文摘In the probiotics manufacturing process,lyophilization damages the cell membrane of microorganisms,reducing their viability and delaying reactivation of their cellular metabolism.The growth phase of microorganisms at the time of lyophilization is thought to significantly affect their viability during storage and reactivation in the intestine.However,no study has systematically investigated the differences in overcoming mechanisms in microorganisms harvested at different growth phases against lyophilization.Therefore,in this study,we comparatively assessed the resistance mechanism of Bifidobacterium animalis ssp.lactis and Lacticaseibacillus rhamnosus harvested at exponential and stationary growth phases.We found that B.animalis ssp.lactis and L.rhamnosus harvested at the stationary phase had shorter lag phase in growth and higher survival rates during storage than those harvested at the exponential phase.As a result of metabolome analysis,the cells harvested at the stationary phase accumulated trehalose and arabinose,which function as cryoprotectants and protect cells from lyophilization-induced damage.These findings could provide a basis for establishing a manufacturing protocol for lyophilized probiotics that can be rapidly reactivated in the intestine to achieve optimal metabolic activity and induce health benefits.
