Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a populat...Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a population-based prospective cohort study.Methods:Altogether,88,000 participants(mean age=62.2±7.9 years,mean±SD)were included from the UK Biobank.Sleep duration(short:<6 h/day;normal:6-8 h/day;long:>8 h/day)and PA of different intensities were measured using a wrist-won accelerometer over a 7-day period between 2013 and 2015.PA was classified according to the median or World Health Organization-recommendation:total volume of PA(high,low),moderate-to-vigorous PA(MVPA)(recommended,not recommended),and light-intensity PA(high,low).Incidence of type 2diabetes was ascertained using hospital records or death registries.Results:During a median follow-up of 7.0 years,1615 incident type 2 diabetes cases were documented.Compared with normal sleep duration,short(hazard ratio(HR)=1.21,95%confidence interval(95%CI):1.03-1.41)but not long sleep duration(HR=1.01,95%CI:0.89-1.15)was associated with excessive type 2 diabetes risk.This increased risk among short sleepers seems to be protected against by PA.Compared with normal sleepers with high or recommended PA,short sleepers with low volume of PA(HR=1.81,95%CI:1.46-2.25),not recommended(below the World Health Organization-recommended level of)MVPA(HR=1.92,95%CI:1.55-2.36),or low light-intensity PA(HR=1.49,95%CI:1.13-1.90)had a higher risk of type 2 diabetes,while short sleepers with a high volume of PA(HR=1.14,95%CI:0.88-1.49),recommended MVPA(HR=1.02,95%CI:0.71-1.48),or high light-intensity PA(HR=1.14,95%CI:0.92-1.41)did not.Conclusion:Accelerometer-measured short but not long sleep duration was associated with a higher risk of incident type 2 diabetes.A higher level of PA,regardless of intensity,potentially ameliorates this excessive risk.展开更多
Background:Whether or not there is targeted pharmacotherapy for dementia,an active and healthy lifestyle that includes physical activity(PA)may be a better option than medication for preventing dementia.We examined th...Background:Whether or not there is targeted pharmacotherapy for dementia,an active and healthy lifestyle that includes physical activity(PA)may be a better option than medication for preventing dementia.We examined the association between leisure-time sedentary behavior(SB)and the risk of dementia incidence and mortality.We further quantified the effect on dementia risk of replacing sedentary time with an equal amount of time spent on different physical activities.Methods:In the UK Biobank,484,169 participants(mean age=56.5 years;45.2%men)free of dementia were followed from baseline(2006-2010)through July 30,2021.A standard questionnaire measured individual leisure-time SB(watching TV,computer use,and driving)and PA(walking for pleasure,light and heavy do-it-yourself activity,strenuous sports,and other exercise)frequency and duration in the 4 weeks prior to evaluation.Apolipoprotein E(APOE)genotype data were available for a subset of 397,519(82.1%)individuals.A Cox proportional hazard model and an isotemporal substitution model were used in this study.Results:During a median 12.4 years of follow-up,6904 all-cause dementia cases and 2115 deaths from dementia were recorded.In comparison to participants with leisure-time SB<5 h/day,the hazard ratio((HR),95%confidence interval(95%CI))of dementia incidence was 1.07(1.02-1.13)for 5-8 h/day and 1.25(1.13-1.38)for>8 h/day,and the HR of dementia mortality was 1.35(1.12-1.61)for>8 h/day.A 1 standard deviation increment of sedentary time(2.33 h/day)was strongly associated with a higher incidence of dementia and mortality(HR=1.06,95%CI:1.03-1.08 and HR=1.07,95%CI:1.03-1.12,respectively).The association between sedentary time and the risk of developing dementia was more profound in subjects<60 years than in those>60 years(HR=1.26,95%CI:1.00-1.58 vs.HR=1.21,95%CI:1.08-1.35 in>8 h/day,p for interaction=0.013).Replacing 30 min/day of leisure sedentary time with an equal time spent in total PA was associated with a6%decreased risk and 9%decreased mortality from dementia,with exercise(e.g.,swimming,cycling,aerobics,bowling)showing the strongest benefit(HR=0.82,95%CI:0.78-0.86 and HR=0.79,95%CI:0.72-0.86).Compared with APOEε4 noncarriers,APOEε4 carriers are more likely to see a decrease in Alzheimer’s disease incidence and mortality when PA is substituted for SB.Conclusion:Leisure-time SB was positively associated with the risk of dementia incidence and mortality.Replacing sedentary time with equal time spent doing PA may be associated with a significant reduction in dementia incidence and mortality risk.展开更多
Background Individuals with type 2 diabetes mellitus(T2DM)are more vulnerable to social disconnection compared with the general population;however,there are few relevant studies investigating this issue.Aims To invest...Background Individuals with type 2 diabetes mellitus(T2DM)are more vulnerable to social disconnection compared with the general population;however,there are few relevant studies investigating this issue.Aims To investigate whether social isolation or loneliness may be associated with subsequent risk of developing major adverse cardiovascular events,whether these associations vary according to fatal and non-fatal outcomes and how behavioural,psychological and physiological factors mediate these associations.Methods This longitudinal analysis included data from 19360 individuals with T2DM at baseline(2006-2010)from the UK Biobank.Social isolation and loneliness were measured using self-report questionnaires.The study outcomes included the first events of myocardial infarction(MI)or stroke(n=2273)and all-cause(n=2820)or cardiovascular disease-related mortality through linked hospital data ordeath registries.Results Over a median follow-up of 12.4 years(interquartile range(IQR):11.6-13.3 years),participants who were more socially isolated(most social isolation vs least social isolation)experienced increased risks for all-cause(hazard ratio(HR):1.33,95%confidence interval(Cl):1.19 to 1.47)and cardiovascular disease(HR:1.36,95%Cl:1.17 to 1.59)mortality but not first Ml or stroke.Loneliness(yes vs no)was associated with a greater risk for a composite of incident MI or stroke(HR:1.37,95%Cl:1.19 to 1.57)but not mortality.Social isolation was associated with fatal Ml and stroke,whereas loneliness was associated with non-fatal Ml and stroke.The significant associations of social isolation and loneliness with outcomes were mainly mediated by behavioural factors(mediating proportion:17.8%-28.2%and 17.6%-17.8%,respectively).Conclusions Among individuals with T2DM,social isolation and loneliness are associated with a greater risk of developing major adverse cardiovascular events,with differences in both risks stratified according to fatal and non-fatal events and underlying mediating factors.展开更多
Genome sequencing has revealed that actinomycetes possess the potential to produce many more secondary metabolites than previously thought.The existing challenge is to devise efficient methods to activate these silent...Genome sequencing has revealed that actinomycetes possess the potential to produce many more secondary metabolites than previously thought.The existing challenge is to devise efficient methods to activate these silent biosynthetic gene clusters(BGCs).In Streptomyces ansochromogenes,disruption of wbl A,a pleiotropic regulatory gene,activated the expression of cryptic tylosin analogues and abolished nikkomycin production simultaneously.Overexpressing pathway-specific regulatory genes tylR1 and tylR2 can also trigger the biosynthesis of silent tylosin analogues,in which TylR1 exerted its function via enhancing tylR2 expression.Bacterial one-hybrid system experiments unveiled that Wbl A directly inhibits the transcription of tylR1 and tylR2 to result in the silence of tylosin analogues BGC.Furthermore,Wbl A can activate the nikkomycin production through up-regulating the transcription of pleiotropic regulatory gene adp A.More interestingly,Adp A can activate san G(an activator gene in nikkomycin BGC)but repress wbl A.Our studies provide a valuable insight into the complex functions of pleiotropic regulators.展开更多
For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing e...For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing energy consumption and achieving sustainable development.Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks,a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task.A solution method based on a novel bi-level genetic algorithm(BGA),in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs,respectively,is designed.The validity of the model and the algorithm is verified by simulation experiments,which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared.The results show that,for the given task,the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization,and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged.Comparison results indicate that our proposed approach could efficiently find solutions within 6%optimality gaps.Energy consumption is dropped by an average of 15%.展开更多
Microorganisms act as a double-edged sword that can bring benefits and diseases to humans.Their physiological and metabolic processes are under precise control of intricate regulatory networks,in which signaling syste...Microorganisms act as a double-edged sword that can bring benefits and diseases to humans.Their physiological and metabolic processes are under precise control of intricate regulatory networks,in which signaling systems are critical for cells coordinating or competing with each other to overcome unfavorable environmental conditions,including the prompt and acute responses to endogenous or exogenous stimuli.展开更多
Genetic modification of large DNA fragments(gene clusters) is of great importance in synthetic biology and combinatorial biosynthesis as it facilitates rational design and modification of natural products to increase ...Genetic modification of large DNA fragments(gene clusters) is of great importance in synthetic biology and combinatorial biosynthesis as it facilitates rational design and modification of natural products to increase their value and productivity.In this study,we developed a method for scarless and precise modification of large gene clusters by using RecET/RED-mediated polymerase chain reaction(PCR) targeting combined with Gibson assembly.In this strategy,the biosynthetic genes for peptidyl moieties(HPHT) in the nikkomycin biosynthetic gene cluster were replaced with those for carbamoylpolyoxamic acid(CPOAA)from the polyoxin biosynthetic gene cluster to generate a^40 kb hybrid gene cluster in Escherichia coli with a reusable targeting cassette.The reconstructed cluster was introduced into Streptomyces lividans TK23 for heterologous expression and the expected hybrid antibiotic,polynik A,was obtained and verified.This study provides an efficient strategy for gene cluster reconstruction and modification that could be applied in synthetic biology and combinatory biosynthesis to synthesize novel bioactive metabolites or to improve antibiotic production.展开更多
Dear Editor,Streptomyces can produce a large variety of secondary metabolites as a major source of anti-infective, antitumor or immune-suppressive agents widely applied in clinical treatment. Antibiotics-resistant bac...Dear Editor,Streptomyces can produce a large variety of secondary metabolites as a major source of anti-infective, antitumor or immune-suppressive agents widely applied in clinical treatment. Antibiotics-resistant bacteria are spreading at alarming rates.展开更多
Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clu...Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clusters(cluster A and cluster B),corresponding to biosyntheses of K-252 c(staurosporine aglycone) and sugar moiety, were identified in Streptomyces fradiae CGMCC 4.576 and heterologously expressed in Streptomyces coelicolor M1146 separately or together. Sta R, a cluster-situated LAL family regulator, activates staurosporine biosynthesis by binding to the promoter regions of sta O-sta C and sta G-sta N. The conserved sequences GGGGG and GCGCG were found through gradually truncating promoters of sta O and sta G, and further determined by mutational experiments. Overexpression of sta R with the supplementation of 0.01 g L^–1 Fe SO4 increased staurosporine production to 5.2-fold compared with that of the parental strain Streptomyces fradiae CGMCC 4.576 in GYM medium. Our results provided an approach for improvement of staurosporine production mediated by a positive regulator and established the basis for dissecting the regulatory mechanisms of other indolocarbazole compounds with clinical application value.展开更多
Genome sequencing of more than 80 thermophiles has provided powerful databases for the preliminary determination of genes essential to thermal adaptation(Berka et al.,2003;Berezovsky and Shakhnovich,2005;Andrews et al...Genome sequencing of more than 80 thermophiles has provided powerful databases for the preliminary determination of genes essential to thermal adaptation(Berka et al.,2003;Berezovsky and Shakhnovich,2005;Andrews et al.,2010).A laboratory strain of Thermoanaerobacter tengcongensis MB4 has been shown to grow at temperatures over the展开更多
Cell-cell communication is critical for bacterial survival in natural habitats,in which miscellaneous regulatory networks are encompassed.However,elucidating the interaction networks of a microbial community has been ...Cell-cell communication is critical for bacterial survival in natural habitats,in which miscellaneous regulatory networks are encompassed.However,elucidating the interaction networks of a microbial community has been hindered by the population complexity.This study reveals thatγ-butyrolactone(GBL)molecules from Streptomyces species,the major antibiotic producers,can directly bind to the acyl-homoserine lactone(AHL)receptor of Chromobacterium violaceum and influence violacein production controlled by the quorum sensing(QS)system.Subsequently,the widespread responses of more Gram-negative bacterial AHL receptors to Gram-positive Streptomyces signaling molecules are unveiled.Based on the cross-talk between GBL and AHL signaling systems,combinatorial regulatory circuits(CRC)are designed and proved to be workable in Escherichia coli(E.coli).It is significant that the QS systems of Gram-positive and Gram-negative bacteria can be bridged via native Streptomyces signaling molecules.These findings pave a new path for unlocking the comprehensive cell-cell communications in microbial communities and facilitate the exploitation of innovative regulatory elements for synthetic biology.展开更多
Mureidomycins(MRDs), a group of unique uridyl-peptide antibiotics, exhibit antibacterial activity against the highly refractory pathogen Pseudomonas aeruginosa. Our previous study showed that the cryptic MRD biosynthe...Mureidomycins(MRDs), a group of unique uridyl-peptide antibiotics, exhibit antibacterial activity against the highly refractory pathogen Pseudomonas aeruginosa. Our previous study showed that the cryptic MRD biosynthetic gene cluster(BGC) mrd in Streptomyces roseosporus NRRL 15998 could not be activated by its endogenous regulator 02995 but activated by an exogenous activator Ssa A from sansanmycin’s BGC ssa of Streptomyces sp. strain SS. Here we report the molecular mechanism for this inexplicable regulation. EMSAs and footprinting experiments revealed that Ssa A could directly bind to a 14-nt palindrome sequence of 5′-CTGRCNNNNGTCAG-3′ within six promoter regions of mrd. Disruption of three representative target genes(SSGG-02981, SSGG-02987 and SSGG-02994) showed that the target genes directly controlled by Ssa Awere essential for MRD production. The regulatory function was further investigated by replacing six regions of SSGG-02995 with those of ssa A.Surprisingly, only the replacement of 343–450 nt fragment encoding the 115–150 amino acids(AA) of Ssa A could activate MRD biosynthesis. Further bioinformatics analysis showed that the 115–150 AA situated between two conserved domains of Ssa A.Our findings significantly demonstrate that constitutive expression of a homologous exogenous regulatory gene is an effective strategy to awaken cryptic biosynthetic pathways in Streptomyces.展开更多
基金supported by the National Key R&D Program of China(2021YFC2501500)National Natural Science Foundation of China(82171476)。
文摘Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a population-based prospective cohort study.Methods:Altogether,88,000 participants(mean age=62.2±7.9 years,mean±SD)were included from the UK Biobank.Sleep duration(short:<6 h/day;normal:6-8 h/day;long:>8 h/day)and PA of different intensities were measured using a wrist-won accelerometer over a 7-day period between 2013 and 2015.PA was classified according to the median or World Health Organization-recommendation:total volume of PA(high,low),moderate-to-vigorous PA(MVPA)(recommended,not recommended),and light-intensity PA(high,low).Incidence of type 2diabetes was ascertained using hospital records or death registries.Results:During a median follow-up of 7.0 years,1615 incident type 2 diabetes cases were documented.Compared with normal sleep duration,short(hazard ratio(HR)=1.21,95%confidence interval(95%CI):1.03-1.41)but not long sleep duration(HR=1.01,95%CI:0.89-1.15)was associated with excessive type 2 diabetes risk.This increased risk among short sleepers seems to be protected against by PA.Compared with normal sleepers with high or recommended PA,short sleepers with low volume of PA(HR=1.81,95%CI:1.46-2.25),not recommended(below the World Health Organization-recommended level of)MVPA(HR=1.92,95%CI:1.55-2.36),or low light-intensity PA(HR=1.49,95%CI:1.13-1.90)had a higher risk of type 2 diabetes,while short sleepers with a high volume of PA(HR=1.14,95%CI:0.88-1.49),recommended MVPA(HR=1.02,95%CI:0.71-1.48),or high light-intensity PA(HR=1.14,95%CI:0.92-1.41)did not.Conclusion:Accelerometer-measured short but not long sleep duration was associated with a higher risk of incident type 2 diabetes.A higher level of PA,regardless of intensity,potentially ameliorates this excessive risk.
基金supported by Shanghai Municipal Human Resources and Social Security Bureau(2020074)Clinical Research Plan of SHDC(SHDC2020CR4006)+2 种基金Shanghai Ninth People’s Hospital(YBKA201909)Innovative research team of high-level local universities in Shanghai(SHSMU-ZDCX20212501)Shanghai Municipal Health Commission(2022XD017)。
文摘Background:Whether or not there is targeted pharmacotherapy for dementia,an active and healthy lifestyle that includes physical activity(PA)may be a better option than medication for preventing dementia.We examined the association between leisure-time sedentary behavior(SB)and the risk of dementia incidence and mortality.We further quantified the effect on dementia risk of replacing sedentary time with an equal amount of time spent on different physical activities.Methods:In the UK Biobank,484,169 participants(mean age=56.5 years;45.2%men)free of dementia were followed from baseline(2006-2010)through July 30,2021.A standard questionnaire measured individual leisure-time SB(watching TV,computer use,and driving)and PA(walking for pleasure,light and heavy do-it-yourself activity,strenuous sports,and other exercise)frequency and duration in the 4 weeks prior to evaluation.Apolipoprotein E(APOE)genotype data were available for a subset of 397,519(82.1%)individuals.A Cox proportional hazard model and an isotemporal substitution model were used in this study.Results:During a median 12.4 years of follow-up,6904 all-cause dementia cases and 2115 deaths from dementia were recorded.In comparison to participants with leisure-time SB<5 h/day,the hazard ratio((HR),95%confidence interval(95%CI))of dementia incidence was 1.07(1.02-1.13)for 5-8 h/day and 1.25(1.13-1.38)for>8 h/day,and the HR of dementia mortality was 1.35(1.12-1.61)for>8 h/day.A 1 standard deviation increment of sedentary time(2.33 h/day)was strongly associated with a higher incidence of dementia and mortality(HR=1.06,95%CI:1.03-1.08 and HR=1.07,95%CI:1.03-1.12,respectively).The association between sedentary time and the risk of developing dementia was more profound in subjects<60 years than in those>60 years(HR=1.26,95%CI:1.00-1.58 vs.HR=1.21,95%CI:1.08-1.35 in>8 h/day,p for interaction=0.013).Replacing 30 min/day of leisure sedentary time with an equal time spent in total PA was associated with a6%decreased risk and 9%decreased mortality from dementia,with exercise(e.g.,swimming,cycling,aerobics,bowling)showing the strongest benefit(HR=0.82,95%CI:0.78-0.86 and HR=0.79,95%CI:0.72-0.86).Compared with APOEε4 noncarriers,APOEε4 carriers are more likely to see a decrease in Alzheimer’s disease incidence and mortality when PA is substituted for SB.Conclusion:Leisure-time SB was positively associated with the risk of dementia incidence and mortality.Replacing sedentary time with equal time spent doing PA may be associated with a significant reduction in dementia incidence and mortality risk.
基金funded by the National Natural Science Foundation of China(32100880)Guangzhou Municipal Key Discipline in Medicine(2021-2023)Guangzhou High-level Clinical Key Specialty and Guangzhou Research-oriented Hospital.
文摘Background Individuals with type 2 diabetes mellitus(T2DM)are more vulnerable to social disconnection compared with the general population;however,there are few relevant studies investigating this issue.Aims To investigate whether social isolation or loneliness may be associated with subsequent risk of developing major adverse cardiovascular events,whether these associations vary according to fatal and non-fatal outcomes and how behavioural,psychological and physiological factors mediate these associations.Methods This longitudinal analysis included data from 19360 individuals with T2DM at baseline(2006-2010)from the UK Biobank.Social isolation and loneliness were measured using self-report questionnaires.The study outcomes included the first events of myocardial infarction(MI)or stroke(n=2273)and all-cause(n=2820)or cardiovascular disease-related mortality through linked hospital data ordeath registries.Results Over a median follow-up of 12.4 years(interquartile range(IQR):11.6-13.3 years),participants who were more socially isolated(most social isolation vs least social isolation)experienced increased risks for all-cause(hazard ratio(HR):1.33,95%confidence interval(Cl):1.19 to 1.47)and cardiovascular disease(HR:1.36,95%Cl:1.17 to 1.59)mortality but not first Ml or stroke.Loneliness(yes vs no)was associated with a greater risk for a composite of incident MI or stroke(HR:1.37,95%Cl:1.19 to 1.57)but not mortality.Social isolation was associated with fatal Ml and stroke,whereas loneliness was associated with non-fatal Ml and stroke.The significant associations of social isolation and loneliness with outcomes were mainly mediated by behavioural factors(mediating proportion:17.8%-28.2%and 17.6%-17.8%,respectively).Conclusions Among individuals with T2DM,social isolation and loneliness are associated with a greater risk of developing major adverse cardiovascular events,with differences in both risks stratified according to fatal and non-fatal events and underlying mediating factors.
基金supported by the National Key Research and Development Program of China(2020YFA0907800)the National Natural Science Foundation of China(32170043,82173720)the Beijing Natural Science Foundation(7212153)。
文摘Genome sequencing has revealed that actinomycetes possess the potential to produce many more secondary metabolites than previously thought.The existing challenge is to devise efficient methods to activate these silent biosynthetic gene clusters(BGCs).In Streptomyces ansochromogenes,disruption of wbl A,a pleiotropic regulatory gene,activated the expression of cryptic tylosin analogues and abolished nikkomycin production simultaneously.Overexpressing pathway-specific regulatory genes tylR1 and tylR2 can also trigger the biosynthesis of silent tylosin analogues,in which TylR1 exerted its function via enhancing tylR2 expression.Bacterial one-hybrid system experiments unveiled that Wbl A directly inhibits the transcription of tylR1 and tylR2 to result in the silence of tylosin analogues BGC.Furthermore,Wbl A can activate the nikkomycin production through up-regulating the transcription of pleiotropic regulatory gene adp A.More interestingly,Adp A can activate san G(an activator gene in nikkomycin BGC)but repress wbl A.Our studies provide a valuable insight into the complex functions of pleiotropic regulators.
基金This study is supported by the Natural Science Foundation of China under Grant Nos.61673228 and 61072260the Science Technology Program of Qingdao(21-1-2-16-zhz).
文摘For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing energy consumption and achieving sustainable development.Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks,a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task.A solution method based on a novel bi-level genetic algorithm(BGA),in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs,respectively,is designed.The validity of the model and the algorithm is verified by simulation experiments,which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared.The results show that,for the given task,the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization,and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged.Comparison results indicate that our proposed approach could efficiently find solutions within 6%optimality gaps.Energy consumption is dropped by an average of 15%.
基金the National Key Research and Development Program of China(2018YFA0901900)Beijing Natural Science Foundation(7212153)the National Natural Science Foundation of China(82173720)。
文摘Microorganisms act as a double-edged sword that can bring benefits and diseases to humans.Their physiological and metabolic processes are under precise control of intricate regulatory networks,in which signaling systems are critical for cells coordinating or competing with each other to overcome unfavorable environmental conditions,including the prompt and acute responses to endogenous or exogenous stimuli.
基金supported by grants from the Ministry of Science and Technology of China(2013CB734001 and 2015CB150600)the National Natural Science Foundation of China(31370097 and 31571281)
文摘Genetic modification of large DNA fragments(gene clusters) is of great importance in synthetic biology and combinatorial biosynthesis as it facilitates rational design and modification of natural products to increase their value and productivity.In this study,we developed a method for scarless and precise modification of large gene clusters by using RecET/RED-mediated polymerase chain reaction(PCR) targeting combined with Gibson assembly.In this strategy,the biosynthetic genes for peptidyl moieties(HPHT) in the nikkomycin biosynthetic gene cluster were replaced with those for carbamoylpolyoxamic acid(CPOAA)from the polyoxin biosynthetic gene cluster to generate a^40 kb hybrid gene cluster in Escherichia coli with a reusable targeting cassette.The reconstructed cluster was introduced into Streptomyces lividans TK23 for heterologous expression and the expected hybrid antibiotic,polynik A,was obtained and verified.This study provides an efficient strategy for gene cluster reconstruction and modification that could be applied in synthetic biology and combinatory biosynthesis to synthesize novel bioactive metabolites or to improve antibiotic production.
基金supported by grants from the Ministry of Science and Technology of China (2015CB150600)the National Natural Science Foundation of China (31571281 and 31771378)
文摘Dear Editor,Streptomyces can produce a large variety of secondary metabolites as a major source of anti-infective, antitumor or immune-suppressive agents widely applied in clinical treatment. Antibiotics-resistant bacteria are spreading at alarming rates.
基金supported by the National Natural Science Foundation of China (31800029 and 31771378)Beijing Natural Science Foundation (5184034)the National Key Research and Development Program of China (2018YFA0901904)
文摘Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clusters(cluster A and cluster B),corresponding to biosyntheses of K-252 c(staurosporine aglycone) and sugar moiety, were identified in Streptomyces fradiae CGMCC 4.576 and heterologously expressed in Streptomyces coelicolor M1146 separately or together. Sta R, a cluster-situated LAL family regulator, activates staurosporine biosynthesis by binding to the promoter regions of sta O-sta C and sta G-sta N. The conserved sequences GGGGG and GCGCG were found through gradually truncating promoters of sta O and sta G, and further determined by mutational experiments. Overexpression of sta R with the supplementation of 0.01 g L^–1 Fe SO4 increased staurosporine production to 5.2-fold compared with that of the parental strain Streptomyces fradiae CGMCC 4.576 in GYM medium. Our results provided an approach for improvement of staurosporine production mediated by a positive regulator and established the basis for dissecting the regulatory mechanisms of other indolocarbazole compounds with clinical application value.
基金supported by the grants from the National Natural Science Foundation of China(Nos.31270110,31370097 and 31200072)
文摘Genome sequencing of more than 80 thermophiles has provided powerful databases for the preliminary determination of genes essential to thermal adaptation(Berka et al.,2003;Berezovsky and Shakhnovich,2005;Andrews et al.,2010).A laboratory strain of Thermoanaerobacter tengcongensis MB4 has been shown to grow at temperatures over the
基金supported by the National Key Research and Development Program of China(2018YFA0901900 and 2020YFA0907700)the National Natural Science Foundation of China(31771378 and 31800029)。
文摘Cell-cell communication is critical for bacterial survival in natural habitats,in which miscellaneous regulatory networks are encompassed.However,elucidating the interaction networks of a microbial community has been hindered by the population complexity.This study reveals thatγ-butyrolactone(GBL)molecules from Streptomyces species,the major antibiotic producers,can directly bind to the acyl-homoserine lactone(AHL)receptor of Chromobacterium violaceum and influence violacein production controlled by the quorum sensing(QS)system.Subsequently,the widespread responses of more Gram-negative bacterial AHL receptors to Gram-positive Streptomyces signaling molecules are unveiled.Based on the cross-talk between GBL and AHL signaling systems,combinatorial regulatory circuits(CRC)are designed and proved to be workable in Escherichia coli(E.coli).It is significant that the QS systems of Gram-positive and Gram-negative bacteria can be bridged via native Streptomyces signaling molecules.These findings pave a new path for unlocking the comprehensive cell-cell communications in microbial communities and facilitate the exploitation of innovative regulatory elements for synthetic biology.
基金This work was supported by the National Key Research and Development Program of China(2020YFA0907800 and 2018YFA0901900)the National Natural Science Foundation of China(81773615,31771378 and 31800029).
文摘Mureidomycins(MRDs), a group of unique uridyl-peptide antibiotics, exhibit antibacterial activity against the highly refractory pathogen Pseudomonas aeruginosa. Our previous study showed that the cryptic MRD biosynthetic gene cluster(BGC) mrd in Streptomyces roseosporus NRRL 15998 could not be activated by its endogenous regulator 02995 but activated by an exogenous activator Ssa A from sansanmycin’s BGC ssa of Streptomyces sp. strain SS. Here we report the molecular mechanism for this inexplicable regulation. EMSAs and footprinting experiments revealed that Ssa A could directly bind to a 14-nt palindrome sequence of 5′-CTGRCNNNNGTCAG-3′ within six promoter regions of mrd. Disruption of three representative target genes(SSGG-02981, SSGG-02987 and SSGG-02994) showed that the target genes directly controlled by Ssa Awere essential for MRD production. The regulatory function was further investigated by replacing six regions of SSGG-02995 with those of ssa A.Surprisingly, only the replacement of 343–450 nt fragment encoding the 115–150 amino acids(AA) of Ssa A could activate MRD biosynthesis. Further bioinformatics analysis showed that the 115–150 AA situated between two conserved domains of Ssa A.Our findings significantly demonstrate that constitutive expression of a homologous exogenous regulatory gene is an effective strategy to awaken cryptic biosynthetic pathways in Streptomyces.
