Contamination of meats and meat products by pathogenic microorganisms is responsible for a significant percentage of outbreaks of foodborne illness.There are also concerns over the carcinogenic potential of dietary ni...Contamination of meats and meat products by pathogenic microorganisms is responsible for a significant percentage of outbreaks of foodborne illness.There are also concerns over the carcinogenic potential of dietary nitrate and nitrite in processed meat products.The past few decades have seen an extensive search for novel technologies alternative to synthetic chemical preservatives to reduce the level of contamination of foods by pathogenic and spoilage microbes.This review provides a general overview of natural preservatives with potential applications in the meat industry,including phages and their endolysins,bacteriocins,microbial lipopeptides,antimicrobial peptides of plant or insect origin,and essential oils or extracts of plant origins.Instead of providing summary data from the published literature,we attempt to elaborate the challenges facing the development of novel natural preservatives as antimicrobial hurdles,taking into consideration the sharp contrast between extensive studies in this particular field and very limited industrial use.More specifically,we emphasize the great importance of having streamlined approaches and methodological guidelines in the research and development of natural preservatives so that the journey to their industrial use for safer meats and meat products could be shortened or made easier.展开更多
Background:Schwann cell-like cells(SCLCs),differentiated from mesenchymal stem cells,have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies.However,certain clinical obstacle...Background:Schwann cell-like cells(SCLCs),differentiated from mesenchymal stem cells,have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies.However,certain clinical obstacles limit their application.Hence,the primary aim of this study was to investigate the role of exosomes derived from SCLCs(SCLCs-exo)in peripheral nerve regeneration.Methods:SCLCs were differentiated from human amniotic mesenchymal stem cells(hAMSCs)in vitro and validated by immunofluorescence,real-time quantitative PCR and western blot analysis.Exosomes derived from hAMSCs(hAMSCs-exo)and SCLCs were isolated by ultracentrifugation and validated by nanoparticle tracking analysis,WB analysis and electron microscopy.A prefab-ricated nerve graft was used to deliver hAMSCs-exo or SCLCs-exo in an injured sciatic nerve rat model.The effects of hAMSCs-exo or SCLCs-exo on rat peripheral nerve injury(PNI)regeneration were determined based on the recovery of neurological function and histomorphometric variation.The effects of hAMSCs-exo or SCLCs-exo on Schwann cells were also determined via cell prolifer-ation and migration assessment.Results:SCLCs significantly expressed the Schwann cell markers glial fibrillary acidic protein and S100.Compared to hAMSCs-exo,SCLCs-exo significantly enhanced motor function recov-ery,attenuated gastrocnemius muscle atrophy and facilitated axonal regrowth,myelin forma-tion and angiogenesis in the rat model.Furthermore,hAMSCs-exo and SCLCs-exo were effi-ciently absorbed by Schwann cells.However,compared to hAMSCs-exo,SCLCs-exo signifi-cantly promoted the proliferation and migration of Schwann cells.SCLCs-exo also significantly upregulated the expression of a glial cell-derived neurotrophic factor,myelin positive regulators(SRY-box transcription factor 10,early growth response protein 2 and organic cation/carnitine transporter 6)and myelin proteins(myelin basic protein and myelin protein zero)in Schwann cells.Conclusions:These findings suggest that SCLCs-exo can more efficiently promote PNI regeneration than hAMSCs-exo and are a potentially novel therapeutic approach for treating PNI.展开更多
The inevitable deterioration of the lubrication conditions in a gearbox in service can change the tribological properties of the meshing teeth. In turn, such changes can significantly affect the dynamic responses and ...The inevitable deterioration of the lubrication conditions in a gearbox in service can change the tribological properties of the meshing teeth. In turn, such changes can significantly affect the dynamic responses and running status of gear systems. This paper investigates such an effect by utilizing virtual prototype technology to model and simulate the dynamics of a wind turbine gearbox system. The change in the lubrication conditions is modeled by the changes in the friction coefficients, thereby indicating that poor lubrication causes not only increased frictional losses but also significant changes in the dynamic responses. These results are further demon-strated by the mean and root mean square values calculated by the simulated responses under different friction coefficients. In addition, the spectrum exhibits significant changes in the first, second, and third harmonics of the meshing components. The findings and simulation method of this study provide theoretical bases for the development of accurate diagnostic techniques.展开更多
Accumulating evidence indicates that early and essential events for receptor-like kinase(RLK)function involve both autophosphorylation and substrate phosphorylation.However,the structural and biochemical basis for the...Accumulating evidence indicates that early and essential events for receptor-like kinase(RLK)function involve both autophosphorylation and substrate phosphorylation.However,the structural and biochemical basis for these events is largely unclear.Here,we used RLK FERONIA(FER)as a model and crystallized its core kinase domain(FER-KD)and two FER-KD mutants(K565R,S525A)in complexes with ATP/ADP and Mg^(2+) in the unphosphorylated state.Unphosphorylated FER-KD was found to adopt an unexpected active conformation in its crystal structure.Moreover,unphosphorylated FER-KD mutants with reduced(S525A)or no catalytic activity(K565R)also adopt similar active conformations.Biochemical studies revealed that FER-KD is a dual-specificity kinase,and its autophosphorylation is accomplished via an intermolecular mechanism.Further investigations confirmed that initiating substrate phosphorylation requires autophosphorylation of the activation segment on T696,S701,and Y704.This study reveals the structural and biochemical basis for the activation and regulatory mechanism of FER,providing a paradigm for the early steps in RLK signaling initiation.展开更多
Accumulated evidence emerges that dynamic changes in human gut microbiota and microbial metabolites can alter the ecological balance of symbiotic hosts.The gut microbiota plays a role in various diseases through diffe...Accumulated evidence emerges that dynamic changes in human gut microbiota and microbial metabolites can alter the ecological balance of symbiotic hosts.The gut microbiota plays a role in various diseases through different mechanisms.More and more attention has been paid to the effects that human microbiota extends beyond the gut.This review summarized the current understanding of the roles that gut microbiota plays in hematopoietic regulation and the occurrence and development of benign and malignant hematologic diseases.The progress of the application of microbiota in treatment was discussed in order to provide new insights into clinical diagnosis and treatment in the future.展开更多
The dynamic regulation of chromatin accessibility is one of the prominent characteristics of eukaryotic genome. The inaccessible regions are mainly located in heterochromatin, which is multilevel compressed and access...The dynamic regulation of chromatin accessibility is one of the prominent characteristics of eukaryotic genome. The inaccessible regions are mainly located in heterochromatin, which is multilevel compressed and access restricted. The remaining accessible loci are generally located in the euchromatin, which have less nucleosome occupancy and higher regulatory activity. The opening of chromatin is the most important prerequisite for DNA transcription, replication, and damage repair, which is regulated by genetic, epigenetic, environmental, and other factors, playing a vital role in multiple biological progresses. Currently, based on the susceptibility difference of occupied or free DNA to enzymatic cleavage, solubility, methylation, and transposition, there are many methods to detect chromatin accessibility both in bulk and single-cell level. Through combining with high-throughput sequencing, the genome-wide chromatin accessibility landscape of many tissues and cells types also have been constructed. The chromatin accessibility feature is distinct in different tissues and biological states. Research on the regulation network of chromatin accessibility is crucial for uncovering the secret of various biological processes. In this review, we comprehensively introduced the major functions and mechanisms of chromatin accessibility variation in different physiological and pathological processes, meanwhile, the targeted therapies based on chromatin dynamics regulation are also summarized.展开更多
基金sponsored in part by the National Program on Key Research Project of China(No.2019YFE0103900)the Zhejiang Ningbo Public Welfare Science and Technology Key Project(No.2022S006)the National Natural Science Foundation of China(No.32172849).
文摘Contamination of meats and meat products by pathogenic microorganisms is responsible for a significant percentage of outbreaks of foodborne illness.There are also concerns over the carcinogenic potential of dietary nitrate and nitrite in processed meat products.The past few decades have seen an extensive search for novel technologies alternative to synthetic chemical preservatives to reduce the level of contamination of foods by pathogenic and spoilage microbes.This review provides a general overview of natural preservatives with potential applications in the meat industry,including phages and their endolysins,bacteriocins,microbial lipopeptides,antimicrobial peptides of plant or insect origin,and essential oils or extracts of plant origins.Instead of providing summary data from the published literature,we attempt to elaborate the challenges facing the development of novel natural preservatives as antimicrobial hurdles,taking into consideration the sharp contrast between extensive studies in this particular field and very limited industrial use.More specifically,we emphasize the great importance of having streamlined approaches and methodological guidelines in the research and development of natural preservatives so that the journey to their industrial use for safer meats and meat products could be shortened or made easier.
基金supported by the InnovationGroup Major Research Project of Guizhou Province Education Department(No.Qianjiaohe KY[2017]043)the Science and Technology Support Project of Guizhou Province(2020-5012)+3 种基金the PhD Fund of Scientific Research Foundation of the Affiliated Hospital of ZunyiMedical University(2020-03)the National Nature Science Foundation of China(81660325)the Collaborative Innovation Center of the Chinese Ministry of Education(2020-39)the Master Fund of Scientific Research Foundation of the Affiliated Hospital of Zunyi Medical University(2016-35).
文摘Background:Schwann cell-like cells(SCLCs),differentiated from mesenchymal stem cells,have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies.However,certain clinical obstacles limit their application.Hence,the primary aim of this study was to investigate the role of exosomes derived from SCLCs(SCLCs-exo)in peripheral nerve regeneration.Methods:SCLCs were differentiated from human amniotic mesenchymal stem cells(hAMSCs)in vitro and validated by immunofluorescence,real-time quantitative PCR and western blot analysis.Exosomes derived from hAMSCs(hAMSCs-exo)and SCLCs were isolated by ultracentrifugation and validated by nanoparticle tracking analysis,WB analysis and electron microscopy.A prefab-ricated nerve graft was used to deliver hAMSCs-exo or SCLCs-exo in an injured sciatic nerve rat model.The effects of hAMSCs-exo or SCLCs-exo on rat peripheral nerve injury(PNI)regeneration were determined based on the recovery of neurological function and histomorphometric variation.The effects of hAMSCs-exo or SCLCs-exo on Schwann cells were also determined via cell prolifer-ation and migration assessment.Results:SCLCs significantly expressed the Schwann cell markers glial fibrillary acidic protein and S100.Compared to hAMSCs-exo,SCLCs-exo significantly enhanced motor function recov-ery,attenuated gastrocnemius muscle atrophy and facilitated axonal regrowth,myelin forma-tion and angiogenesis in the rat model.Furthermore,hAMSCs-exo and SCLCs-exo were effi-ciently absorbed by Schwann cells.However,compared to hAMSCs-exo,SCLCs-exo signifi-cantly promoted the proliferation and migration of Schwann cells.SCLCs-exo also significantly upregulated the expression of a glial cell-derived neurotrophic factor,myelin positive regulators(SRY-box transcription factor 10,early growth response protein 2 and organic cation/carnitine transporter 6)and myelin proteins(myelin basic protein and myelin protein zero)in Schwann cells.Conclusions:These findings suggest that SCLCs-exo can more efficiently promote PNI regeneration than hAMSCs-exo and are a potentially novel therapeutic approach for treating PNI.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 51575177）, the China Scholarship Council, the China Postdoctoral Science Foundation, and the Science and Technology Department of Hunan Province （Grant No. 2015JC3108）.
文摘The inevitable deterioration of the lubrication conditions in a gearbox in service can change the tribological properties of the meshing teeth. In turn, such changes can significantly affect the dynamic responses and running status of gear systems. This paper investigates such an effect by utilizing virtual prototype technology to model and simulate the dynamics of a wind turbine gearbox system. The change in the lubrication conditions is modeled by the changes in the friction coefficients, thereby indicating that poor lubrication causes not only increased frictional losses but also significant changes in the dynamic responses. These results are further demon-strated by the mean and root mean square values calculated by the simulated responses under different friction coefficients. In addition, the spectrum exhibits significant changes in the first, second, and third harmonics of the meshing components. The findings and simulation method of this study provide theoretical bases for the development of accurate diagnostic techniques.
基金supported by grants from the National Natural Science Foundation of China(32160064,31871396,31571444,and 32000916)the State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources(SKLCUSA-a201806)+3 种基金the China Postdoctoral Science Foundation(2019M662764)the Hunan Provincial Natural Science Foundation of China(2021JJ40050)the Guangxi Natural Science Foundation(2020GXNSFFA297007)the Guangxi Key Laboratory for Sugarcane Biology(GXKLSCB-20190304).
文摘Accumulating evidence indicates that early and essential events for receptor-like kinase(RLK)function involve both autophosphorylation and substrate phosphorylation.However,the structural and biochemical basis for these events is largely unclear.Here,we used RLK FERONIA(FER)as a model and crystallized its core kinase domain(FER-KD)and two FER-KD mutants(K565R,S525A)in complexes with ATP/ADP and Mg^(2+) in the unphosphorylated state.Unphosphorylated FER-KD was found to adopt an unexpected active conformation in its crystal structure.Moreover,unphosphorylated FER-KD mutants with reduced(S525A)or no catalytic activity(K565R)also adopt similar active conformations.Biochemical studies revealed that FER-KD is a dual-specificity kinase,and its autophosphorylation is accomplished via an intermolecular mechanism.Further investigations confirmed that initiating substrate phosphorylation requires autophosphorylation of the activation segment on T696,S701,and Y704.This study reveals the structural and biochemical basis for the activation and regulatory mechanism of FER,providing a paradigm for the early steps in RLK signaling initiation.
基金supported by grants from the National Key Research and Development Program of China(2022YFA1103500,2020YFE0203000)the National Natural Science Foundation of China(81890990,82222003,92268117,82161138028)+2 种基金the Zhejiang Provincial Natural Science Foundation of China(Z24H080001)the Haihe Laboratory of Cell Ecosystem Innovation Fund(22HHXBSS00016)the CAMS Initiative for Innovative Medicine(2021-I2M-1-019).
文摘Accumulated evidence emerges that dynamic changes in human gut microbiota and microbial metabolites can alter the ecological balance of symbiotic hosts.The gut microbiota plays a role in various diseases through different mechanisms.More and more attention has been paid to the effects that human microbiota extends beyond the gut.This review summarized the current understanding of the roles that gut microbiota plays in hematopoietic regulation and the occurrence and development of benign and malignant hematologic diseases.The progress of the application of microbiota in treatment was discussed in order to provide new insights into clinical diagnosis and treatment in the future.
基金supported by the National Natural Science Foundation of China(No.82203598)Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0536).
文摘The dynamic regulation of chromatin accessibility is one of the prominent characteristics of eukaryotic genome. The inaccessible regions are mainly located in heterochromatin, which is multilevel compressed and access restricted. The remaining accessible loci are generally located in the euchromatin, which have less nucleosome occupancy and higher regulatory activity. The opening of chromatin is the most important prerequisite for DNA transcription, replication, and damage repair, which is regulated by genetic, epigenetic, environmental, and other factors, playing a vital role in multiple biological progresses. Currently, based on the susceptibility difference of occupied or free DNA to enzymatic cleavage, solubility, methylation, and transposition, there are many methods to detect chromatin accessibility both in bulk and single-cell level. Through combining with high-throughput sequencing, the genome-wide chromatin accessibility landscape of many tissues and cells types also have been constructed. The chromatin accessibility feature is distinct in different tissues and biological states. Research on the regulation network of chromatin accessibility is crucial for uncovering the secret of various biological processes. In this review, we comprehensively introduced the major functions and mechanisms of chromatin accessibility variation in different physiological and pathological processes, meanwhile, the targeted therapies based on chromatin dynamics regulation are also summarized.
