Most dehydration-responsive element-binding (DREB) factors interact specifically with the dehydration-responsive element (DRE) and control the expression of many stress-inducible genes in Arabidopsis. In rice (Oryza s...Most dehydration-responsive element-binding (DREB) factors interact specifically with the dehydration-responsive element (DRE) and control the expression of many stress-inducible genes in Arabidopsis. In rice (Oryza sativa L. cv. Lansheng), we cloned three DREB homologs: OsDREB1-1, OsDREB4- 1, and OsDREB4-2. The deduced amino acid sequences revealed that each protein contained a potential nuclear localization signal, an AP2 DNA-binding domain, and a possible acidic activation domain. The yeast one-hybrid assay indicated that both OsDREB4-1 and OsDREB4-2 proteins specifically bound to DRE and activated expression of the dual reporter genes of histidine (HIS3) and galactosidase (LacZ). In rice seedlings,expression of OsDREB4-1 was induced by dehydration and high salt, whereas OsDREB1-1 and OsDREB4-2 were expressed constitutively. Under normal growth conditions, OsDREB1-1 was expressed strongly in the leaf, sheath, and spike, was expressed relatively weak in the stem and only faintly expressed in the roots,whereas expression of transcripts of OsDREB4-1 and OsDREB4-2 was higher in the roots, stem, and spike,lower in the leaf, and undetectable in the sheath. Together, these results imply that expression of the OsDREB genes could be controlled by specific aspects of differentiation or development. Thus, OsDREB4-1 could function as a trans-acting factor in the DRE/DREB regulated stress-responsive pathway.展开更多
Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes pa...Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes participate in auxin homeostasis by catalyzing auxin conjugation and bounding free indole-3-acetic acid (IAA) to amino acids. However, how GH3 genes function in responses to abiotic stresses and various hormones in maize is largely unknown. Here, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmGH3 family genes from maize. The results showed that 13 ZmGH3 genes were mapped on five maize chromosomes (total 10 chromosomes). Highly diversified gene structures and tissue-specific expression patterns suggested the possibility of function diversification for these genes in response to environmental stresses and hormone stimuli. The expression patterns of ZmGH3 genes are responsive to several abiotic stresses (salt, drought and cadmium) and major stress-related hormones (abscisic acid, salicylic acid and jasmonic acid). Various environmental factors suppress auxin free IAA contents in maize roots suggesting that these abiotic stresses and hormones might alter GH3-mediated auxin levels. The respon-siveness of ZmGH3 genes to a wide range of abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses.展开更多
Along with innovation in ICT technology and the spread of the internet,the online network,through its“technological empowerment”of citizens and governments,has driven a series of institutional changes designed to pr...Along with innovation in ICT technology and the spread of the internet,the online network,through its“technological empowerment”of citizens and governments,has driven a series of institutional changes designed to promote government responsiveness.The global spread of online political deliberation is indeed an achievement of the internetdriven construction of responsive government.In recent years,the Chinese government has vigorously promoted online political deliberation,established virtual platforms to build bridges between netizens and public power,brought internet activism into institutional channels,and implemented political absorption and online consultation.Under the influence of policy initiatives and local innovations,China has created diversified response systems that strengthen the institutionalization of online political deliberation and thereby enable this system to play an active role in improving government capacity and regulating the relationship between the state and society.At present,China has seven types of online response:the Communist Party Committee-led mode,the mixed mode,the governmentled mode and the modes led by the departments in charge of absorption,business,supervision departments,and petitioning.Empirical studies show that the diversity and degree of institutionalization of online political deliberation significantly affect institutional performance and that political authority and professionalism are important features that enable the different response systems to influence institutional performance.In short,the endogenous elements of the response system—level of institutionalization and institutional diversity—are key factors in institutional performance.展开更多
As emerging artificial biomimetic membranes, smart or intelligent membranes that are able to respond to environmental stimuli are attracting ever-increasing interests from various fields. Their permeation properties i...As emerging artificial biomimetic membranes, smart or intelligent membranes that are able to respond to environmental stimuli are attracting ever-increasing interests from various fields. Their permeation properties including hydraulic permeability and diffusional permeability can be dramatically controlled or adjusted self-regulatively in response to small chemical and/or physical stimuli in their environments. Such environmental stimuli-responsive smart membranes could find myriad applications in numerous fields ranging from controlled release to separations. Here the trans-membrane mass-transfer and membrane separation is introduced as the beginning to initiate the requirement of smart membranes, and then bio-inspired design of environmental stimuli-responsive smart membranes and four essential elements for smart membranes are introduced and discussed. Next, smart membrane types and their applications as smart tools for controllable mass-transfer in controlled release and separations are reviewed. The research tooics in the near future are also suggested.展开更多
In this study, we identified a defense-related major latex protein （MLP） from upland cotton （designated GhMLP28） and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton p...In this study, we identified a defense-related major latex protein （MLP） from upland cotton （designated GhMLP28） and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton plants, with higher accumulation in the root. Expression of the GhMLP28 gene was induced by Verticillium dahliae inoculation and was responsive to defense signaling molecules, including ethylene, jas- monic acid, and salicylic acid. Knockdown of GhMLP28 expression by virus-induced gene silencing re- sulted in increased susceptibility of cotton plants to V. dahliae infection, while ectopic overexpression of GhMLP28 in tobacco improved the disease tolerance of the transgenic plants. Further analysis revealed that GhMLP28 interacted with cotton ethylene response factor 6 （GhERF6） and facilitated the binding of GhERF6 to GCC-box element. Transient expression assay demonstrated that GhMLP28 enhanced the tran- scription factor activity of GhERF6, which led to the augmented expression of some GCC-box genes. GhMLP28 proteins were located in both the nucleus and cytoplasm and their nuclear distribution was dependent on the presence of GhERF6. Collectively, these results demonstrate that GhMLP28 acts as a positive regulator of GhERF6, and synergetic actions of the two proteins may contribute substantially to protection against V. dahliae infection in cotton plants.展开更多
Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of TiO2 nanoparticles. Site-selective deposition of metal or metal oxide on TiO2 specific exposed crystal faces...Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of TiO2 nanoparticles. Site-selective deposition of metal or metal oxide on TiO2 specific exposed crystal faces successfully proceeded using the unique reactivity properties on the surface of TiO2 nanoparticles under photoexcitation. A remarkable improvement ofphotocatalytic activity of shape- controlled brookite and rutile TiO2 nanorods with modification of Fe^3＋ compounds was observed under visible light. Crystal face-selective metal compound modification on exposed crystal faces of TiO2 nanorods with brookite and futile phases was successfully prepared. Brookite and rutile TiO2 nanorods prepared by site-selective modification with metal compounds should be ideal visible-light responsive TiO2 photocatalysts because of the remarkable suppression of back electron transfer from TiO2 to oxidized metal com- pounds on the surface of the TiO2 nanorod with a brookite or rutile phase. In this paper, the development of exposed crystal face-controlled TiO2 nanorods with rutile and brookite phases was described. The obtained rutile and brookite TiO2 nanorod, showing remarkably high activity for degra- dation of organic compounds compared with the photocatalytic activities of anatase fine particles （ST-01）, is one of the most active commercially available photocatalysts for environmental cleanup in Japan. The technology of visiblelight responsive treatment for morphology-controlled rutile and brookite TiO2 nanorods by crystal face-selective modification of Fe^3＋ compounds was also discussed in this paper. The Fe^3＋ compound-modified rutile and brookite TiO2 nanorods show much higher activity than conventional visible-light responsive N-doped TiO2, which is commercially available in Japan.展开更多
The Populus euphratica stress responsive zinc-finger protein gene PSTZ, which encodes a protein including typical Cys2/His2 zinc finger structure, was isolated by reverse transcription-polymerase chain reaction from P...The Populus euphratica stress responsive zinc-finger protein gene PSTZ, which encodes a protein including typical Cys2/His2 zinc finger structure, was isolated by reverse transcription-polymerase chain reaction from P. euphratica. Northern hybridization revealed that its expression was induced under drought and salt stress conditions. To examine its function, cDNA of the PSTZ gene, driven by the cauliflower mosaic virus 35S promoter, was cloned into a plant expression vector pBin438 and introduced into tobacco plants. Transgenic tobacco showed an enhanced salt tolerance, suggesting that PSTZ may play a role in plant responsiveness to salt stress.展开更多
Spurred by significant progress in materials chemistry and drug delivery, charge-reversal nanocarriers are being developed to deliver anticancer formulations in spatial-, temporal- and dosagecontrolled approaches. Cha...Spurred by significant progress in materials chemistry and drug delivery, charge-reversal nanocarriers are being developed to deliver anticancer formulations in spatial-, temporal- and dosagecontrolled approaches. Charge-reversal nanoparticles can release their drug payload in response to specific stimuli that alter the charge on their surface. They can elude clearance from the circulation and be activated by protonation, enzymatic cleavage, or a molecular conformational change. In this review, we discuss the physiological basis for, and recent advances in the design of charge-reversal nanoparticles that are able to control drug biodistribution in response to specific stimuli, endogenous factors(changes in p H,redox gradients, or enzyme concentration) or exogenous factors(light or thermos-stimulation).展开更多
The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of gene...The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of genes controlled by Wnt responsive DNA elements(WREs). T-cell factor/Lymphoid enhancer factor transcription factors bind WREs and recruit the β-catenin transcriptional co-activator to activate target gene expression. Deregulated expression of the c-MYC proto-oncogene(MYC) by aberrant Wnt/β-catenin signaling drives colorectal carcinogenesis. In this review,we discuss the current literature pertaining to the identification and characterization of WREs that control oncogenic MYC expression in CRCs. A common theme has emerged whereby these WREs often map distally to the MYC genomic locus and control MYC gene expression through long-range chromatin loops with the MYC proximal promoter. We propose that by determining which of these WREs is critical for CRC pathogenesis,novel strategies can be developed to treat individuals suffering from this disease.展开更多
Smart polymers have enormous potential in various applications.In particular,smart polymeric drug delivery systems have been explored as“intelligent”delivery systems able to release,at the appropriate time and site ...Smart polymers have enormous potential in various applications.In particular,smart polymeric drug delivery systems have been explored as“intelligent”delivery systems able to release,at the appropriate time and site of action,entrapped drugs in response to specific physiological triggers.These polymers exhibit a non-linear response to a small stimulus leading to a macroscopic alteration in their structure/properties.The responses vary widely from swelling/contraction to disintegration.Synthesis of new polymers and crosslinkers with greater biocompatibility and better biodegradability would increase and enhance current applications.The most fascinating features of the smart polymers arise from their versatility and tunable sensitivity.The most significant weakness of all these external stimuli-sensitive polymers is slow response time.The versatility of polymer sources and their combinatorial synthesis make it possible to tune polymer sensitivity to a given stimulus within a narrow range.Development of smart polymer systems may lead to more accurate and programmable drug delivery.In this review,we discuss various mechanisms by which polymer systems are assembled in situ to form implanted devices for sustained release of therapeutic macromolecules,and we highlight various applications in the field of advanced drug delivery.展开更多
Phytohormone abscisic acid (ABA) was critical for many plant growth and developmental processesincluding seed maturation, germination and response to environmental factors. With the purpose to detectthe possible ABA r...Phytohormone abscisic acid (ABA) was critical for many plant growth and developmental processesincluding seed maturation, germination and response to environmental factors. With the purpose to detectthe possible ABA related signal transduction pathways, we tried to isolate ABA-regulated genes throughcDNA macroarray technology using ABA-treated rice seedling as materials (under treatment for 2, 4, 8 and12 h). Of 6144 cDNA clones tested, 37 differential clones showing induction or suppression for at least onetime, were isolated. Of them 30 and 7 were up- or down-regulated respectively. Sequence analyses revealedthat the putative encoded proteins were involved in different possible processes, including transcription,metabolism and resistance, photosynthesis, signal transduction, and seed maturation. 6 cDNA clones werefound to encode proteins with unknown functions. Regulation by ABA of 7 selected clones relating to signaltransduction or metabolism was confirmed by reverse transcription PCR. In addition, some clones werefurther shown to be regulated by other plant growth regulators including auxin and brassinosteroid, which,however, indicated the complicated interactions of plant hormones. Possible signal transduction pathwaysinvolved in ABA were discussed.展开更多
Dental caries is one of the most prevalent human diseases resulting from tooth demineralization caused by acid production of bacteria plaque.It remains challenges for current practice to specifically identify,interven...Dental caries is one of the most prevalent human diseases resulting from tooth demineralization caused by acid production of bacteria plaque.It remains challenges for current practice to specifically identify,intervene and interrupt the development of caries while restoring defects.In this study,inspired by natural dental plaque,a stimuli-responsive multidrug delivery system(PMs@NaF-SAP)has been developed to prevent tooth decay and promote enamel restoration.Classic spherical core-shell structures of micelles dual-loaded with antibacterial and restorative agents are self-assembled into bacteria-responsive multidrug delivery system based on the pH-cleavable boronate ester bond,followed by conjugation with salivary-acquired peptide(SAP)to endow the nanoparticle with strong adhesion to tooth enamel.The constructed PMs@NaF-SAP specifically adheres to tooth,identifies cariogenic conditions and intelligently releases drugs at acidic pH,thereby providing antibacterial adhesion and cariogenic biofilm resistance,and restoring the microarchitecture and mechanical properties of demineralized teeth.Topical treatment with PMs@NaF-SAP effectively diminishes the onset and severity of caries without impacting oral microbiota diversity or surrounding mucosal tissues.These findings demonstrate this novel nanotherapy has potential as a promising biomedical application for caries prevention and tooth defect restoration while resisting biofilm-associated diseases in a controlled manner activated by pathological bacteria.展开更多
Bacterial infection and related diseases are threatening the health of human beings.Photocatalytic disinfection as a simple and low-cost disinfection strategy is attracting more and more attention.In this work,TiO2 na...Bacterial infection and related diseases are threatening the health of human beings.Photocatalytic disinfection as a simple and low-cost disinfection strategy is attracting more and more attention.In this work,TiO2 nanoparticles(NPs)were modified by co-doping of Ce and Er using the sol-gel method,which endowed TiO2 NPs with enhanced visible light photocatalytic performance but not pure ultraviolet photocatalytic properties compared the untreated TiO2.Our results disclosed that as the doping content of Er increased,the photocatalytic activity of modified TiO2 NPs initially increased and subsequently decreased.The same trend occurred for Ce doping.When the doping dose of Er and Ce is 0.5 mol%and 0.2 mol%,the 0.5Ce0.2Ti-O calcined at 800℃ presented the best antibacterial properties,with the antibacterial efficiency of 91.23%and 92.8%for Staphylococcus aureus and Escherichia coli,respectively.The existence of Er ions is thought to successfully turn the near-infrared radiation into visible region,which is easier to be absorbed by TiO2 NPs.Meanwhile,the addition of Ce ions can effectively extend spectral response range and inhibit the recombination of electrons and holes,enhancing the photocatalytic disinfection activity of co-doped TiO2.展开更多
基金国家重点基础研究发展计划(973计划)，the National Special Program for Research and Industrialization of Transgenic Plants，国家科技攻关项目
文摘Most dehydration-responsive element-binding (DREB) factors interact specifically with the dehydration-responsive element (DRE) and control the expression of many stress-inducible genes in Arabidopsis. In rice (Oryza sativa L. cv. Lansheng), we cloned three DREB homologs: OsDREB1-1, OsDREB4- 1, and OsDREB4-2. The deduced amino acid sequences revealed that each protein contained a potential nuclear localization signal, an AP2 DNA-binding domain, and a possible acidic activation domain. The yeast one-hybrid assay indicated that both OsDREB4-1 and OsDREB4-2 proteins specifically bound to DRE and activated expression of the dual reporter genes of histidine (HIS3) and galactosidase (LacZ). In rice seedlings,expression of OsDREB4-1 was induced by dehydration and high salt, whereas OsDREB1-1 and OsDREB4-2 were expressed constitutively. Under normal growth conditions, OsDREB1-1 was expressed strongly in the leaf, sheath, and spike, was expressed relatively weak in the stem and only faintly expressed in the roots,whereas expression of transcripts of OsDREB4-1 and OsDREB4-2 was higher in the roots, stem, and spike,lower in the leaf, and undetectable in the sheath. Together, these results imply that expression of the OsDREB genes could be controlled by specific aspects of differentiation or development. Thus, OsDREB4-1 could function as a trans-acting factor in the DRE/DREB regulated stress-responsive pathway.
基金funded by the National Natural Science Foundation of China (31401935)Zhejiang Provincial Natural Science Foundation of China (LQ14C060001 and LQ13C020004)
文摘Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes participate in auxin homeostasis by catalyzing auxin conjugation and bounding free indole-3-acetic acid (IAA) to amino acids. However, how GH3 genes function in responses to abiotic stresses and various hormones in maize is largely unknown. Here, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmGH3 family genes from maize. The results showed that 13 ZmGH3 genes were mapped on five maize chromosomes (total 10 chromosomes). Highly diversified gene structures and tissue-specific expression patterns suggested the possibility of function diversification for these genes in response to environmental stresses and hormone stimuli. The expression patterns of ZmGH3 genes are responsive to several abiotic stresses (salt, drought and cadmium) and major stress-related hormones (abscisic acid, salicylic acid and jasmonic acid). Various environmental factors suppress auxin free IAA contents in maize roots suggesting that these abiotic stresses and hormones might alter GH3-mediated auxin levels. The respon-siveness of ZmGH3 genes to a wide range of abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses.
文摘Along with innovation in ICT technology and the spread of the internet,the online network,through its“technological empowerment”of citizens and governments,has driven a series of institutional changes designed to promote government responsiveness.The global spread of online political deliberation is indeed an achievement of the internetdriven construction of responsive government.In recent years,the Chinese government has vigorously promoted online political deliberation,established virtual platforms to build bridges between netizens and public power,brought internet activism into institutional channels,and implemented political absorption and online consultation.Under the influence of policy initiatives and local innovations,China has created diversified response systems that strengthen the institutionalization of online political deliberation and thereby enable this system to play an active role in improving government capacity and regulating the relationship between the state and society.At present,China has seven types of online response:the Communist Party Committee-led mode,the mixed mode,the governmentled mode and the modes led by the departments in charge of absorption,business,supervision departments,and petitioning.Empirical studies show that the diversity and degree of institutionalization of online political deliberation significantly affect institutional performance and that political authority and professionalism are important features that enable the different response systems to influence institutional performance.In short,the endogenous elements of the response system—level of institutionalization and institutional diversity—are key factors in institutional performance.
基金Supported by the National Basic Research Program of China （2009CB623407）, and the National Natural Science Foundation of China （20825622, 20806049, 20906064, 20990220, 21036002, 21076127, 21136006）.
文摘As emerging artificial biomimetic membranes, smart or intelligent membranes that are able to respond to environmental stimuli are attracting ever-increasing interests from various fields. Their permeation properties including hydraulic permeability and diffusional permeability can be dramatically controlled or adjusted self-regulatively in response to small chemical and/or physical stimuli in their environments. Such environmental stimuli-responsive smart membranes could find myriad applications in numerous fields ranging from controlled release to separations. Here the trans-membrane mass-transfer and membrane separation is introduced as the beginning to initiate the requirement of smart membranes, and then bio-inspired design of environmental stimuli-responsive smart membranes and four essential elements for smart membranes are introduced and discussed. Next, smart membrane types and their applications as smart tools for controllable mass-transfer in controlled release and separations are reviewed. The research tooics in the near future are also suggested.
文摘In this study, we identified a defense-related major latex protein （MLP） from upland cotton （designated GhMLP28） and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton plants, with higher accumulation in the root. Expression of the GhMLP28 gene was induced by Verticillium dahliae inoculation and was responsive to defense signaling molecules, including ethylene, jas- monic acid, and salicylic acid. Knockdown of GhMLP28 expression by virus-induced gene silencing re- sulted in increased susceptibility of cotton plants to V. dahliae infection, while ectopic overexpression of GhMLP28 in tobacco improved the disease tolerance of the transgenic plants. Further analysis revealed that GhMLP28 interacted with cotton ethylene response factor 6 （GhERF6） and facilitated the binding of GhERF6 to GCC-box element. Transient expression assay demonstrated that GhMLP28 enhanced the tran- scription factor activity of GhERF6, which led to the augmented expression of some GCC-box genes. GhMLP28 proteins were located in both the nucleus and cytoplasm and their nuclear distribution was dependent on the presence of GhERF6. Collectively, these results demonstrate that GhMLP28 acts as a positive regulator of GhERF6, and synergetic actions of the two proteins may contribute substantially to protection against V. dahliae infection in cotton plants.
基金financially supported by the Advanced Catalytic Transformation Program for Carbon Utilization(ACT-C)Japan Science and Technology Agency(JST)
文摘Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of TiO2 nanoparticles. Site-selective deposition of metal or metal oxide on TiO2 specific exposed crystal faces successfully proceeded using the unique reactivity properties on the surface of TiO2 nanoparticles under photoexcitation. A remarkable improvement ofphotocatalytic activity of shape- controlled brookite and rutile TiO2 nanorods with modification of Fe^3＋ compounds was observed under visible light. Crystal face-selective metal compound modification on exposed crystal faces of TiO2 nanorods with brookite and futile phases was successfully prepared. Brookite and rutile TiO2 nanorods prepared by site-selective modification with metal compounds should be ideal visible-light responsive TiO2 photocatalysts because of the remarkable suppression of back electron transfer from TiO2 to oxidized metal com- pounds on the surface of the TiO2 nanorod with a brookite or rutile phase. In this paper, the development of exposed crystal face-controlled TiO2 nanorods with rutile and brookite phases was described. The obtained rutile and brookite TiO2 nanorod, showing remarkably high activity for degra- dation of organic compounds compared with the photocatalytic activities of anatase fine particles （ST-01）, is one of the most active commercially available photocatalysts for environmental cleanup in Japan. The technology of visiblelight responsive treatment for morphology-controlled rutile and brookite TiO2 nanorods by crystal face-selective modification of Fe^3＋ compounds was also discussed in this paper. The Fe^3＋ compound-modified rutile and brookite TiO2 nanorods show much higher activity than conventional visible-light responsive N-doped TiO2, which is commercially available in Japan.
基金Supported by the National Key Technology Research and Development Program (2006BAD03A01)the Hi-Tech Research and Development Program of China (2007AA10Z106)the Key Program Project of Ministry of Education (104242).
文摘The Populus euphratica stress responsive zinc-finger protein gene PSTZ, which encodes a protein including typical Cys2/His2 zinc finger structure, was isolated by reverse transcription-polymerase chain reaction from P. euphratica. Northern hybridization revealed that its expression was induced under drought and salt stress conditions. To examine its function, cDNA of the PSTZ gene, driven by the cauliflower mosaic virus 35S promoter, was cloned into a plant expression vector pBin438 and introduced into tobacco plants. Transgenic tobacco showed an enhanced salt tolerance, suggesting that PSTZ may play a role in plant responsiveness to salt stress.
文摘Spurred by significant progress in materials chemistry and drug delivery, charge-reversal nanocarriers are being developed to deliver anticancer formulations in spatial-, temporal- and dosagecontrolled approaches. Charge-reversal nanoparticles can release their drug payload in response to specific stimuli that alter the charge on their surface. They can elude clearance from the circulation and be activated by protonation, enzymatic cleavage, or a molecular conformational change. In this review, we discuss the physiological basis for, and recent advances in the design of charge-reversal nanoparticles that are able to control drug biodistribution in response to specific stimuli, endogenous factors(changes in p H,redox gradients, or enzyme concentration) or exogenous factors(light or thermos-stimulation).
基金Supported by Institutional funds provided by the Pennsylvania State University College of Medicine
文摘The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of genes controlled by Wnt responsive DNA elements(WREs). T-cell factor/Lymphoid enhancer factor transcription factors bind WREs and recruit the β-catenin transcriptional co-activator to activate target gene expression. Deregulated expression of the c-MYC proto-oncogene(MYC) by aberrant Wnt/β-catenin signaling drives colorectal carcinogenesis. In this review,we discuss the current literature pertaining to the identification and characterization of WREs that control oncogenic MYC expression in CRCs. A common theme has emerged whereby these WREs often map distally to the MYC genomic locus and control MYC gene expression through long-range chromatin loops with the MYC proximal promoter. We propose that by determining which of these WREs is critical for CRC pathogenesis,novel strategies can be developed to treat individuals suffering from this disease.
文摘Smart polymers have enormous potential in various applications.In particular,smart polymeric drug delivery systems have been explored as“intelligent”delivery systems able to release,at the appropriate time and site of action,entrapped drugs in response to specific physiological triggers.These polymers exhibit a non-linear response to a small stimulus leading to a macroscopic alteration in their structure/properties.The responses vary widely from swelling/contraction to disintegration.Synthesis of new polymers and crosslinkers with greater biocompatibility and better biodegradability would increase and enhance current applications.The most fascinating features of the smart polymers arise from their versatility and tunable sensitivity.The most significant weakness of all these external stimuli-sensitive polymers is slow response time.The versatility of polymer sources and their combinatorial synthesis make it possible to tune polymer sensitivity to a given stimulus within a narrow range.Development of smart polymer systems may lead to more accurate and programmable drug delivery.In this review,we discuss various mechanisms by which polymer systems are assembled in situ to form implanted devices for sustained release of therapeutic macromolecules,and we highlight various applications in the field of advanced drug delivery.
基金Researches were supported by "the State Key Project of Basic Research, G1999011604" "Key Project of Knowledge Innovation, CAS", "the National Natural Science Foundation of China, No.30070073" "National Sciences Foundation of Pan-Deng". We thank Prof.
文摘Phytohormone abscisic acid (ABA) was critical for many plant growth and developmental processesincluding seed maturation, germination and response to environmental factors. With the purpose to detectthe possible ABA related signal transduction pathways, we tried to isolate ABA-regulated genes throughcDNA macroarray technology using ABA-treated rice seedling as materials (under treatment for 2, 4, 8 and12 h). Of 6144 cDNA clones tested, 37 differential clones showing induction or suppression for at least onetime, were isolated. Of them 30 and 7 were up- or down-regulated respectively. Sequence analyses revealedthat the putative encoded proteins were involved in different possible processes, including transcription,metabolism and resistance, photosynthesis, signal transduction, and seed maturation. 6 cDNA clones werefound to encode proteins with unknown functions. Regulation by ABA of 7 selected clones relating to signaltransduction or metabolism was confirmed by reverse transcription PCR. In addition, some clones werefurther shown to be regulated by other plant growth regulators including auxin and brassinosteroid, which,however, indicated the complicated interactions of plant hormones. Possible signal transduction pathwaysinvolved in ABA were discussed.
基金supported by the National Natural Science Foundation of China(No.82001106,81970918,81901043).
文摘Dental caries is one of the most prevalent human diseases resulting from tooth demineralization caused by acid production of bacteria plaque.It remains challenges for current practice to specifically identify,intervene and interrupt the development of caries while restoring defects.In this study,inspired by natural dental plaque,a stimuli-responsive multidrug delivery system(PMs@NaF-SAP)has been developed to prevent tooth decay and promote enamel restoration.Classic spherical core-shell structures of micelles dual-loaded with antibacterial and restorative agents are self-assembled into bacteria-responsive multidrug delivery system based on the pH-cleavable boronate ester bond,followed by conjugation with salivary-acquired peptide(SAP)to endow the nanoparticle with strong adhesion to tooth enamel.The constructed PMs@NaF-SAP specifically adheres to tooth,identifies cariogenic conditions and intelligently releases drugs at acidic pH,thereby providing antibacterial adhesion and cariogenic biofilm resistance,and restoring the microarchitecture and mechanical properties of demineralized teeth.Topical treatment with PMs@NaF-SAP effectively diminishes the onset and severity of caries without impacting oral microbiota diversity or surrounding mucosal tissues.These findings demonstrate this novel nanotherapy has potential as a promising biomedical application for caries prevention and tooth defect restoration while resisting biofilm-associated diseases in a controlled manner activated by pathological bacteria.
基金supported by the National Science Fund for Distinguished Young Scholars 51925104National Natural Science Foundation of China nos.51871162,51671081+2 种基金Natural Science Fund of Hubei Province,2018CFA064,RGC/NSFC(N_HKU725-1616)Hong Kong ITC(ITS/287/17,GHX/002/14SZ)as Health and Medical Research Fund(No.03142446).
文摘Bacterial infection and related diseases are threatening the health of human beings.Photocatalytic disinfection as a simple and low-cost disinfection strategy is attracting more and more attention.In this work,TiO2 nanoparticles(NPs)were modified by co-doping of Ce and Er using the sol-gel method,which endowed TiO2 NPs with enhanced visible light photocatalytic performance but not pure ultraviolet photocatalytic properties compared the untreated TiO2.Our results disclosed that as the doping content of Er increased,the photocatalytic activity of modified TiO2 NPs initially increased and subsequently decreased.The same trend occurred for Ce doping.When the doping dose of Er and Ce is 0.5 mol%and 0.2 mol%,the 0.5Ce0.2Ti-O calcined at 800℃ presented the best antibacterial properties,with the antibacterial efficiency of 91.23%and 92.8%for Staphylococcus aureus and Escherichia coli,respectively.The existence of Er ions is thought to successfully turn the near-infrared radiation into visible region,which is easier to be absorbed by TiO2 NPs.Meanwhile,the addition of Ce ions can effectively extend spectral response range and inhibit the recombination of electrons and holes,enhancing the photocatalytic disinfection activity of co-doped TiO2.
