Hypermethylation of the gene regulatory regions are common for many cancer diseases. In this work we applied GLAD-PCR assay for identificating of the aberrantly methylated RCGY sites in the regulatory regions of some ...Hypermethylation of the gene regulatory regions are common for many cancer diseases. In this work we applied GLAD-PCR assay for identificating of the aberrantly methylated RCGY sites in the regulatory regions of some downregulated genes in tissue samples of lung cancer(LC). This list includes EFEMP1, EPHA5, HOXA5, HOXA9, LHX1, MYF6, NID2, OTX1, PAX9, RARB, RASSF1 A, RXRG, SIX6, SKOR1 and TERT genes. The results of DNA samples from 40 cancer and 25 normal lung tissues showed a good diagnostic potential of selected RCGY sites in regulatory regions of MYF6, SIX6, RXRG, LHX1, RASSF1 A and TERT genes with relatively high sensitivity(80.0 %) and specificity(88.0 %) of LC detection in tumor DNA.展开更多
Background:Fiber,as the main product of cotton,provides main raw material for the textile industry.Many key factors have been revealed a significant role in fiber cell development including Myb proteins,phytohormones,...Background:Fiber,as the main product of cotton,provides main raw material for the textile industry.Many key factors have been revealed a significant role in fiber cell development including Myb proteins,phytohormones,fatty acid metabolites,and epigenetic modifications.DNA methylation is one of the important epigenetic modifications to regulate plant development and responses to abiotic or biotic stimuli.In general,DNA methylation consisting of 5mC and 6mA regulates the chromatin structure and gene transcription to affect plant development,however,the detailed role and underlying mechanism of DNA methylation in the fiber development of cotton are yet vague.Results:Here,systematical study of the 5mC and 6mA DNA methylation profiles during the fiber initiation period of Xu142 and its glabrous mutant Xu142fl represented a clear alteration of global DNA methylation associated with fiber cell initiation.Then,the genome-wide identification of genes responsible for methylation regulation at the fifth carbon of cytosine and the sixth carbon of adenine of DNA was operated in Gossypium hirsutum.As a result,13,10,6,and 17 genes were identified for 5mC methylation,5mC demethylation,6mA methylation,and 6mA demethylation,respectively.We then investigated the tissue expression pattern of all these genes,and some genes showed higher expression levels in fiber initiation,among which some displayed a significant change in transcription between Xu142 and Xu142fl.The possible interaction between histone acetylation and DNA methylation in fiber initiation through in vitro culture was studied by dot blot,and the results showed that repressed histone deacetylation by Trichostatin A(TSA)inhibited the global DNA methylation,and some causal genes(e.g.,GhDMT13,GhDAMT2,GhALKBH12,GhDM7)were also identified.Conclusions:In this study,all the findings indicated the interplay between histone acetylation and DNA methylation,supporting their important roles and providing precious clues for the epigenetic modifications associated with DNA methylation in the fiber development of cotton.展开更多
DNA methylation,especially methylation of cytosine in eukaryotic organisms,has been implicated in gene regulation,genomic imprinting,the timing of DNA replication,and determination of chromatin structure.It was report...DNA methylation,especially methylation of cytosine in eukaryotic organisms,has been implicated in gene regulation,genomic imprinting,the timing of DNA replication,and determination of chromatin structure.It was reported that 6.5% of the whole cytosine residues in the nuclear DNA in展开更多
Background and objectives:The occurrence and development of lung cancer are closely linked to epigenetic modification.Abnormal DNA methylation in the CpG island region of genes has been found in many cancers.Protein k...Background and objectives:The occurrence and development of lung cancer are closely linked to epigenetic modification.Abnormal DNA methylation in the CpG island region of genes has been found in many cancers.Protein kinase C delta binding protein(PRKCDBP) is a potential tumor suppressor and its epigenetic changes are found in many human malignancies.This study investigated the possibility of PRKCDBP methylation as a potential biomarker for non-small cell lung cancer(NSCLC).Methods:We measured the methylation levels of PRKCDBP in the three groups of NSCLC tissues.Promoter activity was measured by the dual luciferase assay,with S’-aza-deoxycytidine to examine the effect of demethylation on the expression level of PRKCDBP.Results:The methylation levels of PRKCDBP in tumor tissues and 3 cm para-tumor were higher than those of distant(>10 cm)non-tumor tissues.Receiver operating characteristic(ROC) curve analysis between tumor tissues and distant non-tumor tissues showed that the area under the line(AUC) was 0.717.Dual luciferase experiment confirmed that the promoter region was able to promote gene expression.Meanwhile,in vitro methylation of the fragment(PRKCDBP;e) could significantly reduce the promoter activity of the fragment.Demethylation of 5’-aza-deoxycytidine in lung cancer cell lines A549 and H1299 showed a significant up-regulation of PRKCDBP mRNA levels.Conclusion:PRKCDBP methylation is a potential and promising candidate biomarker for non-small cell lung cancer.展开更多
Neuropsychiatric disorders arise from complex interactions between genetic and environmental factors.DNA methylation,a reversible and environmentally responsive epigenetic regulatory mechanism,serves as a crucial brid...Neuropsychiatric disorders arise from complex interactions between genetic and environmental factors.DNA methylation,a reversible and environmentally responsive epigenetic regulatory mechanism,serves as a crucial bridge linking environmental exposure,gene expression regulation,and neurobehavioral outcomes.During long-duration deep-space missions,astronauts face multiple stressors-including microgravity,cosmic radiation,circadian rhythm disruption,and social isolation,which can induce alterations in DNA methylation and increase the risk of neuropsychiatric disorders.Genome-wide DNA methylation research can be divided into 3 major methodological stages:Study design,sample preparation and detection,and data analysis,each of which can be applied to astronaut neuropsychiatric health monitoring.Systematic comparison of the Illumina MethylationEPIC array and whole-genome bisulfite sequencing reveals their complementary strengths in terms of genomic coverage,resolution,cost,and application scenarios:the array method is cost-effective and suitable for large-scale population studies and longitudinal monitoring,whereas sequencing provides higher resolution and coverage and is more suitable for constructing detailed methylation maps and characterizing individual variation.Furthermore,emerging technologies such as single-cell methylation sequencing,nanopore long-read sequencing,and machine-learning-based multi-omics integration are expected to greatly enhance the precision and interpretability of epigenetic studies.These methodological advances provide key support for establishing DNAmethylation-based monitoring systems for neuropsychiatric risk in astronauts and lay an epigenetic foundation for safeguarding neuropsychiatric health during future long-term deep-space missions.展开更多
Background Thidiazuron(TDZ)is a widely used chemical defoliant in commercial cotton production and is often combined with the herbicide Diuron to form the commercial defoliant mixture known as TDZ·Diuron(T·D...Background Thidiazuron(TDZ)is a widely used chemical defoliant in commercial cotton production and is often combined with the herbicide Diuron to form the commercial defoliant mixture known as TDZ·Diuron(T·D,540 g·L^(-1)suspension).However,due to increasing concerns about the environmental and biological risks posed by Diuron,there is an urgent need to develop safer and more effective alternatives.Jasmonic acid(JA)and its derivatives are key phytohormones in organ senescence and abscission.Results Greenhouse experiments at the seedling stage revealed that Me-JA(0.8 mmol·L^(-1))alone did not induce defoliation.However,its co-application with TDZ(0.45 mmol·L^(-1))at concentrations of 0.6,0.8,and 1.0 mmol·L^(-1)significantly enhanced defoliation efficacy.The most effective combination—TDZ with 0.8 mmol·L^(-1)Me-JA—achieved a 100%defoliation rate at 5 days after treatment(DAT),23.7 percentage points higher than TDZ alone,and comparable to the commercial TDZ·Diuron formulation with equivalent TDZ content.Field trials conducted in Beijing(Shangzhuang),Hebei(Hejian),and Xinjiang(Shihezi)confirmed that the combination of 0.6 mmol·L^(-1)Me-JA with 1.70 mmol·L^(-1)TDZ provided optimal defoliation performance.At 21 DAT,the defoliation rate increased by 13.5–16.3 percentage points compared with TDZ alone.Furthermore,boll opening rates improved by 5.7–12.7 percentage points relative to TDZ-only treatments.Phytohormonal analyses from the Shangzhuang site showed that the combined treatment significantly altered hormone levels in both leaves and petioles.Compared with TDZ alone,the mixture reduced concentrations of auxin(IAA),cytokinins(Z+ZR,iP+iPA,DHZ+DHZR),and gibberellic acid(GA3),while increasing levels of JA,abscisic acid(ABA),and brassinosteroids(BR).These hormonal shifts may underlie the enhanced defoliation observed with the combined treatment.Importantly,the TDZ-Me-JA combination did not adversely affect cotton yield,yield components,or fiber quality.Conclusion The combination of Me-JA and TDZ has a good defoliation effect without affecting crop yield or fiber quality.And it provides a promising foundation for the development of novel,environmentally friendly cotton defoliants.展开更多
Introduction Post-translational modifications of core histones have emerged as a critical player in dynamical regulation of gene expression and accurate chromatin structures<sup>[1-2]</sup>.In recent years...Introduction Post-translational modifications of core histones have emerged as a critical player in dynamical regulation of gene expression and accurate chromatin structures<sup>[1-2]</sup>.In recent years it has been demonstrated that,histone lysine methylation is particularly prominent as one of the most important epigenetic modifications during cell cycles,development and differentiation,and in response to external stimuli,e.g.exogenous growth factors and mechanical stimulation.This epigenetic modification may also be an early event that regulates the gene expression dur-展开更多
OBJECTIVE Normal male aging is associated with declines in levels of the sex steroid hormone testosterone. A large body of evidence supports a neurotrophic role for testosterone in central nervous system. Lipoprotein ...OBJECTIVE Normal male aging is associated with declines in levels of the sex steroid hormone testosterone. A large body of evidence supports a neurotrophic role for testosterone in central nervous system. Lipoprotein lipase(LPL) is also expressed in the brain with highest levels found in the pyramidal cells of the hippocampus, we previous reported LPL-deficient mice exhibited memory disfunction. Testosterone is known to be largely converted to estradiol following aromatization within the hippocampus. Although testosterone has been implicated in lipid metabolism, it remains elusive whether testosterone can regulate brain LPL through DNA methylation mechanism. In order to clarify DNA methylation control exerted by testosterone over LPL gene in central nervous system, and its effect on lipid metabolism, we examined the adult male rat hippocampus to determine whether castration induced testosterone deficiency can affect lipid profile and LPL gene expression through its altered methylation pattern. METHODS Model of aging with declines in levels of the sex steroid hormone testosterone was performed as our previous description. RESULTS(1) Serum testosterone and brain testosterone levels were significantly decreased, which were restored to the control level after testosterone replacement,respectively(P<0.01);(2) Androgen deficiency was not found in Morris water maze and motor performance, however, androgen deficiency increases neurological and cognitive impairment in aged rats.(3)Decreased expression of olfactory marker protein(OMP) in olfactory bulb of SD rats treated with androgen deficiency.(4) The expression of Fox O3 and OMP in the olfactory bulb of androgen deficient rats was down-regulated, accompanied by dysfunction of the olfactory limbic system.(5) Decreased LPL m RNA level and inversely increased LPL promoter methylation level were observed following androgen deficiency and reserved by testosterone replacement.(6) In contrast, androgen deficiency slightly increased estrogen receptor beta(ERβ) m RNA levels and significantly decreased its promoter methylation levels within the hippocampus, and reserved as well by testosterone replacement. CONCLUSION(1) LPL in synaptic plasticity and contributes to a better understanding of the LPL function in the brain, where altered LPL levels are related to learning and memory impairment.(2) Androgen and Fox O3 play an important role in the olfactory cognitive process of the nervous system.(3) LPL expression in hippocampus is actively maintained by sex steroid hormones and that DNA methylation modification may contribute to this homeostatic regulation.展开更多
The impurities in ethyl-2-[[2′-cyanobiphenyl-4-yl] methyl] amino]-3-nitrobenzoate,an intermediate for synthesis of candesartan cilexiti,were detected by LC-MSn. The structural assignment of these impurities was carri...The impurities in ethyl-2-[[2′-cyanobiphenyl-4-yl] methyl] amino]-3-nitrobenzoate,an intermediate for synthesis of candesartan cilexiti,were detected by LC-MSn. The structural assignment of these impurities was carried out by LC-MSn using electrospray ionization source and an ion trap mass analyzer. The formation of the impurities was discussed. Also the fragmentation pathways of these compounds were studied.展开更多
在植物的生长周期里,低温是一个重要的限制因素。植物感受到低温信号以后,CBF/DREB基因受到诱导表达,从而启动下游的COR基因和低温的应激反应。目前人们鉴定了调控CBF/DREB基因的上游作用因子,包括ICE1、CAMTA3、LHY以及CCA1等。但是对...在植物的生长周期里,低温是一个重要的限制因素。植物感受到低温信号以后,CBF/DREB基因受到诱导表达,从而启动下游的COR基因和低温的应激反应。目前人们鉴定了调控CBF/DREB基因的上游作用因子,包括ICE1、CAMTA3、LHY以及CCA1等。但是对于CBF/DREB基因如何在低温条件下受到诱导表达的机理仍不清楚。中国科学院武汉植物园研究员产祝龙与中国科学院上海生命科学研究院上海植物逆境生物学研究中心朱健康合作,发现rdm4(RNA-directed DNA Methylation4)突变体对低温敏感。展开更多
Methyl isobutyl ketone(MIBK) is widely used as extraction agent in hydrometallurgy. As it has a definite solubility in water, so when using MIBK as extraction agent, there will be MIBK in stripping solutions inevitabl...Methyl isobutyl ketone(MIBK) is widely used as extraction agent in hydrometallurgy. As it has a definite solubility in water, so when using MIBK as extraction agent, there will be MIBK in stripping solutions inevitably, which not only pollutes working conditions, but also affects the quality of ultimate product. In order to remove MIBK from aqueous solutions, the means of flat vacuum membrane distillation(VMD) is studied in the paper. The area of the membrane used in the study is 0.02 m 2, the initial volume of feed is 2 L, each experiment was conducted over a time period of 60 120 min. The influences of the factors such as temperature(34.8 55.0 ℃); pressure in the permeate side(10.67 14.67 kPa) and feed flow rate(27.8 69.4 mL/s) were experimentally studied. Increasing the temperature or reducing the pressure in the permeate side results in a faster removal of MIBK; however there is a decrease in removal factor β , increasing the feed flow rate results in a faster removal of MIBK and an increase of removal factor β , especially in the range of lower flow rate. The study indicates that the aim of MIBK removal and recycle from dilute aqueous solutions can be achieved by VMD.展开更多
In a stainless steel autoclave,the synthesis kinetics of dimethyl carbonate(DMC) from urea and methanol was separately investigated without catalyst and with Zn-containing catalyst.Without catalyst,for the first react...In a stainless steel autoclave,the synthesis kinetics of dimethyl carbonate(DMC) from urea and methanol was separately investigated without catalyst and with Zn-containing catalyst.Without catalyst,for the first reaction of DMC synthesis(the reaction of urea with methanol to methyl carbamate(MC)),the reaction kinetics can be described as the first order with respect to the concentrations of both methanol and urea.For the second reaction of DMC synthesis(the reaction of MC with methanol to DMC),the results exhibit characteristics of zero-order reaction.For Zn-containing catalyst,the first reaction is neglected in the kinetics model since its rate is much faster than the second reaction.The macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model,in which a side reaction in forming process of DMC is incorporated since it decreases the yield of DMC drastically at high temperature.The activation energy of the reaction from MC to DMC is 104 kJ/mol while that of the side reaction of DMC is 135 kJ/mol.The highest yield of DMC is 23%.展开更多
基金supported by the Skolkovo Foundation(Under agreement NO.G102/16 06.12.2016г.)
文摘Hypermethylation of the gene regulatory regions are common for many cancer diseases. In this work we applied GLAD-PCR assay for identificating of the aberrantly methylated RCGY sites in the regulatory regions of some downregulated genes in tissue samples of lung cancer(LC). This list includes EFEMP1, EPHA5, HOXA5, HOXA9, LHX1, MYF6, NID2, OTX1, PAX9, RARB, RASSF1 A, RXRG, SIX6, SKOR1 and TERT genes. The results of DNA samples from 40 cancer and 25 normal lung tissues showed a good diagnostic potential of selected RCGY sites in regulatory regions of MYF6, SIX6, RXRG, LHX1, RASSF1 A and TERT genes with relatively high sensitivity(80.0 %) and specificity(88.0 %) of LC detection in tumor DNA.
基金supported financially by National Natural Science Foundation of China(32072022 and 31690093)the Creative Research Groups of China(31621005)Central Public-interest Scientific Institution Basal Research Fund(1610162020010202)for scientific research into non-profit industries。
文摘Background:Fiber,as the main product of cotton,provides main raw material for the textile industry.Many key factors have been revealed a significant role in fiber cell development including Myb proteins,phytohormones,fatty acid metabolites,and epigenetic modifications.DNA methylation is one of the important epigenetic modifications to regulate plant development and responses to abiotic or biotic stimuli.In general,DNA methylation consisting of 5mC and 6mA regulates the chromatin structure and gene transcription to affect plant development,however,the detailed role and underlying mechanism of DNA methylation in the fiber development of cotton are yet vague.Results:Here,systematical study of the 5mC and 6mA DNA methylation profiles during the fiber initiation period of Xu142 and its glabrous mutant Xu142fl represented a clear alteration of global DNA methylation associated with fiber cell initiation.Then,the genome-wide identification of genes responsible for methylation regulation at the fifth carbon of cytosine and the sixth carbon of adenine of DNA was operated in Gossypium hirsutum.As a result,13,10,6,and 17 genes were identified for 5mC methylation,5mC demethylation,6mA methylation,and 6mA demethylation,respectively.We then investigated the tissue expression pattern of all these genes,and some genes showed higher expression levels in fiber initiation,among which some displayed a significant change in transcription between Xu142 and Xu142fl.The possible interaction between histone acetylation and DNA methylation in fiber initiation through in vitro culture was studied by dot blot,and the results showed that repressed histone deacetylation by Trichostatin A(TSA)inhibited the global DNA methylation,and some causal genes(e.g.,GhDMT13,GhDAMT2,GhALKBH12,GhDM7)were also identified.Conclusions:In this study,all the findings indicated the interplay between histone acetylation and DNA methylation,supporting their important roles and providing precious clues for the epigenetic modifications associated with DNA methylation in the fiber development of cotton.
文摘DNA methylation,especially methylation of cytosine in eukaryotic organisms,has been implicated in gene regulation,genomic imprinting,the timing of DNA replication,and determination of chromatin structure.It was reported that 6.5% of the whole cytosine residues in the nuclear DNA in
基金supported by the grants from National Natural Science Foundation of China(to Yuanlin QI,No.81773055)Natural Science Foundation of Fujian Province(to Yuanlin QI,No.2018J01829 and to Mingfang ZHANG,No.2019J01293)+2 种基金Key Talents Training Program of Fujian Provincial Health Commission(to Yuanlin QI,No.2017-ZQN-59 and to Mingfang ZHANG,No.2017-ZQN-60)Joint Funds for the Innovation of Science and Technology of Fujian Province(to Yuanl in QI,No.2017Y9113)K.C.Wong Magna Fund in Ningbo University(to Shiwei DUAN)。
文摘Background and objectives:The occurrence and development of lung cancer are closely linked to epigenetic modification.Abnormal DNA methylation in the CpG island region of genes has been found in many cancers.Protein kinase C delta binding protein(PRKCDBP) is a potential tumor suppressor and its epigenetic changes are found in many human malignancies.This study investigated the possibility of PRKCDBP methylation as a potential biomarker for non-small cell lung cancer(NSCLC).Methods:We measured the methylation levels of PRKCDBP in the three groups of NSCLC tissues.Promoter activity was measured by the dual luciferase assay,with S’-aza-deoxycytidine to examine the effect of demethylation on the expression level of PRKCDBP.Results:The methylation levels of PRKCDBP in tumor tissues and 3 cm para-tumor were higher than those of distant(>10 cm)non-tumor tissues.Receiver operating characteristic(ROC) curve analysis between tumor tissues and distant non-tumor tissues showed that the area under the line(AUC) was 0.717.Dual luciferase experiment confirmed that the promoter region was able to promote gene expression.Meanwhile,in vitro methylation of the fragment(PRKCDBP;e) could significantly reduce the promoter activity of the fragment.Demethylation of 5’-aza-deoxycytidine in lung cancer cell lines A549 and H1299 showed a significant up-regulation of PRKCDBP mRNA levels.Conclusion:PRKCDBP methylation is a potential and promising candidate biomarker for non-small cell lung cancer.
基金supported by the National Natural Science Foundation(82022024)the Graduate Independent Innovation Project of Central South University(2022ZZTS0866),China.
文摘Neuropsychiatric disorders arise from complex interactions between genetic and environmental factors.DNA methylation,a reversible and environmentally responsive epigenetic regulatory mechanism,serves as a crucial bridge linking environmental exposure,gene expression regulation,and neurobehavioral outcomes.During long-duration deep-space missions,astronauts face multiple stressors-including microgravity,cosmic radiation,circadian rhythm disruption,and social isolation,which can induce alterations in DNA methylation and increase the risk of neuropsychiatric disorders.Genome-wide DNA methylation research can be divided into 3 major methodological stages:Study design,sample preparation and detection,and data analysis,each of which can be applied to astronaut neuropsychiatric health monitoring.Systematic comparison of the Illumina MethylationEPIC array and whole-genome bisulfite sequencing reveals their complementary strengths in terms of genomic coverage,resolution,cost,and application scenarios:the array method is cost-effective and suitable for large-scale population studies and longitudinal monitoring,whereas sequencing provides higher resolution and coverage and is more suitable for constructing detailed methylation maps and characterizing individual variation.Furthermore,emerging technologies such as single-cell methylation sequencing,nanopore long-read sequencing,and machine-learning-based multi-omics integration are expected to greatly enhance the precision and interpretability of epigenetic studies.These methodological advances provide key support for establishing DNAmethylation-based monitoring systems for neuropsychiatric risk in astronauts and lay an epigenetic foundation for safeguarding neuropsychiatric health during future long-term deep-space missions.
基金funded by the China Agriculture Research System(CARS–15–16)。
文摘Background Thidiazuron(TDZ)is a widely used chemical defoliant in commercial cotton production and is often combined with the herbicide Diuron to form the commercial defoliant mixture known as TDZ·Diuron(T·D,540 g·L^(-1)suspension).However,due to increasing concerns about the environmental and biological risks posed by Diuron,there is an urgent need to develop safer and more effective alternatives.Jasmonic acid(JA)and its derivatives are key phytohormones in organ senescence and abscission.Results Greenhouse experiments at the seedling stage revealed that Me-JA(0.8 mmol·L^(-1))alone did not induce defoliation.However,its co-application with TDZ(0.45 mmol·L^(-1))at concentrations of 0.6,0.8,and 1.0 mmol·L^(-1)significantly enhanced defoliation efficacy.The most effective combination—TDZ with 0.8 mmol·L^(-1)Me-JA—achieved a 100%defoliation rate at 5 days after treatment(DAT),23.7 percentage points higher than TDZ alone,and comparable to the commercial TDZ·Diuron formulation with equivalent TDZ content.Field trials conducted in Beijing(Shangzhuang),Hebei(Hejian),and Xinjiang(Shihezi)confirmed that the combination of 0.6 mmol·L^(-1)Me-JA with 1.70 mmol·L^(-1)TDZ provided optimal defoliation performance.At 21 DAT,the defoliation rate increased by 13.5–16.3 percentage points compared with TDZ alone.Furthermore,boll opening rates improved by 5.7–12.7 percentage points relative to TDZ-only treatments.Phytohormonal analyses from the Shangzhuang site showed that the combined treatment significantly altered hormone levels in both leaves and petioles.Compared with TDZ alone,the mixture reduced concentrations of auxin(IAA),cytokinins(Z+ZR,iP+iPA,DHZ+DHZR),and gibberellic acid(GA3),while increasing levels of JA,abscisic acid(ABA),and brassinosteroids(BR).These hormonal shifts may underlie the enhanced defoliation observed with the combined treatment.Importantly,the TDZ-Me-JA combination did not adversely affect cotton yield,yield components,or fiber quality.Conclusion The combination of Me-JA and TDZ has a good defoliation effect without affecting crop yield or fiber quality.And it provides a promising foundation for the development of novel,environmentally friendly cotton defoliants.
基金supported in part by NIH HL098472 and NSF CBET0846429supported by China Scholarship Council as well
文摘Introduction Post-translational modifications of core histones have emerged as a critical player in dynamical regulation of gene expression and accurate chromatin structures<sup>[1-2]</sup>.In recent years it has been demonstrated that,histone lysine methylation is particularly prominent as one of the most important epigenetic modifications during cell cycles,development and differentiation,and in response to external stimuli,e.g.exogenous growth factors and mechanical stimulation.This epigenetic modification may also be an early event that regulates the gene expression dur-
基金NBRD Program of China(2016YFC1306302 2016YFC1305903)+3 种基金National Natural Science Foundation of China(81571044 81471633 61450004 and 81171015)
文摘OBJECTIVE Normal male aging is associated with declines in levels of the sex steroid hormone testosterone. A large body of evidence supports a neurotrophic role for testosterone in central nervous system. Lipoprotein lipase(LPL) is also expressed in the brain with highest levels found in the pyramidal cells of the hippocampus, we previous reported LPL-deficient mice exhibited memory disfunction. Testosterone is known to be largely converted to estradiol following aromatization within the hippocampus. Although testosterone has been implicated in lipid metabolism, it remains elusive whether testosterone can regulate brain LPL through DNA methylation mechanism. In order to clarify DNA methylation control exerted by testosterone over LPL gene in central nervous system, and its effect on lipid metabolism, we examined the adult male rat hippocampus to determine whether castration induced testosterone deficiency can affect lipid profile and LPL gene expression through its altered methylation pattern. METHODS Model of aging with declines in levels of the sex steroid hormone testosterone was performed as our previous description. RESULTS(1) Serum testosterone and brain testosterone levels were significantly decreased, which were restored to the control level after testosterone replacement,respectively(P<0.01);(2) Androgen deficiency was not found in Morris water maze and motor performance, however, androgen deficiency increases neurological and cognitive impairment in aged rats.(3)Decreased expression of olfactory marker protein(OMP) in olfactory bulb of SD rats treated with androgen deficiency.(4) The expression of Fox O3 and OMP in the olfactory bulb of androgen deficient rats was down-regulated, accompanied by dysfunction of the olfactory limbic system.(5) Decreased LPL m RNA level and inversely increased LPL promoter methylation level were observed following androgen deficiency and reserved by testosterone replacement.(6) In contrast, androgen deficiency slightly increased estrogen receptor beta(ERβ) m RNA levels and significantly decreased its promoter methylation levels within the hippocampus, and reserved as well by testosterone replacement. CONCLUSION(1) LPL in synaptic plasticity and contributes to a better understanding of the LPL function in the brain, where altered LPL levels are related to learning and memory impairment.(2) Androgen and Fox O3 play an important role in the olfactory cognitive process of the nervous system.(3) LPL expression in hippocampus is actively maintained by sex steroid hormones and that DNA methylation modification may contribute to this homeostatic regulation.
文摘The impurities in ethyl-2-[[2′-cyanobiphenyl-4-yl] methyl] amino]-3-nitrobenzoate,an intermediate for synthesis of candesartan cilexiti,were detected by LC-MSn. The structural assignment of these impurities was carried out by LC-MSn using electrospray ionization source and an ion trap mass analyzer. The formation of the impurities was discussed. Also the fragmentation pathways of these compounds were studied.
文摘在植物的生长周期里,低温是一个重要的限制因素。植物感受到低温信号以后,CBF/DREB基因受到诱导表达,从而启动下游的COR基因和低温的应激反应。目前人们鉴定了调控CBF/DREB基因的上游作用因子,包括ICE1、CAMTA3、LHY以及CCA1等。但是对于CBF/DREB基因如何在低温条件下受到诱导表达的机理仍不清楚。中国科学院武汉植物园研究员产祝龙与中国科学院上海生命科学研究院上海植物逆境生物学研究中心朱健康合作,发现rdm4(RNA-directed DNA Methylation4)突变体对低温敏感。
文摘Methyl isobutyl ketone(MIBK) is widely used as extraction agent in hydrometallurgy. As it has a definite solubility in water, so when using MIBK as extraction agent, there will be MIBK in stripping solutions inevitably, which not only pollutes working conditions, but also affects the quality of ultimate product. In order to remove MIBK from aqueous solutions, the means of flat vacuum membrane distillation(VMD) is studied in the paper. The area of the membrane used in the study is 0.02 m 2, the initial volume of feed is 2 L, each experiment was conducted over a time period of 60 120 min. The influences of the factors such as temperature(34.8 55.0 ℃); pressure in the permeate side(10.67 14.67 kPa) and feed flow rate(27.8 69.4 mL/s) were experimentally studied. Increasing the temperature or reducing the pressure in the permeate side results in a faster removal of MIBK; however there is a decrease in removal factor β , increasing the feed flow rate results in a faster removal of MIBK and an increase of removal factor β , especially in the range of lower flow rate. The study indicates that the aim of MIBK removal and recycle from dilute aqueous solutions can be achieved by VMD.
基金Project(2010ZC034) supported by the Science Foundation of Yunnan Province,ChinaProject(20105314120005) supported by the Research Fund for Doctor Program of Higher Education of China+2 种基金Project(11-12-609) supported by the Open Foundation of State Key Laboratory of Coal Conversion,ChinaProject(KKJD201051012) supported by the Scientific Research Fund of Yunnan Provincial Education Department,ChinaProject(2009-096) supported by the Analysis and Measure Foundation of Kunming University of Scienceand Technology,China
文摘In a stainless steel autoclave,the synthesis kinetics of dimethyl carbonate(DMC) from urea and methanol was separately investigated without catalyst and with Zn-containing catalyst.Without catalyst,for the first reaction of DMC synthesis(the reaction of urea with methanol to methyl carbamate(MC)),the reaction kinetics can be described as the first order with respect to the concentrations of both methanol and urea.For the second reaction of DMC synthesis(the reaction of MC with methanol to DMC),the results exhibit characteristics of zero-order reaction.For Zn-containing catalyst,the first reaction is neglected in the kinetics model since its rate is much faster than the second reaction.The macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model,in which a side reaction in forming process of DMC is incorporated since it decreases the yield of DMC drastically at high temperature.The activation energy of the reaction from MC to DMC is 104 kJ/mol while that of the side reaction of DMC is 135 kJ/mol.The highest yield of DMC is 23%.
