Accounting for the gains and losses of ecological assets holds scientific significance in sustaining human well-being.Based on related research on ecological assets,we established a county-scale ecological asset accou...Accounting for the gains and losses of ecological assets holds scientific significance in sustaining human well-being.Based on related research on ecological assets,we established a county-scale ecological asset accounting technology system by analyzing the temporal and spatial variations of county-level ecological assets in China from 1990 to 2018 and clarified the factors which caused the gains and losses of ecological assets.On these bases,optimization and promotion pathways were proposed.The results show that the number of counties dominated by farmland and forest ecological resources accounted for about 45%and 37%of the total counties,respectively.From 1990 to 2018,the quality of county-level ecological stock assets showed an increasing trend,while the water conservation volume decreased in nearly 70%of the counties.The number of counties with the gains(47%)and losses(37%)of ecological flow assets demonstrated spatial patterns which showed the same segmentation characteristics as the“Hu Huanyong Line”,that is,the counties in the vastness of northwest China experienced significant gains,while decreases were widespread in eastern and southern China.The change of ecological assets in more than 70%of the counties was driven by climate change and human activities.The average degree of impact of human activities driving the ecological asset gains in counties was about 80%,while that of climate change causing the ecological asset losses was about 60%.According to various ecological resource types,gain and loss status,and its driving factors,counties in China can be classified into five types:climate change mitigation,climate change adaptation,ecological resources restoration,ecological resources protection,and ecological resources management.Our results indicate that differentiated optimization and promotion pathways can be adopted to achieve desired ecological asset gains.展开更多
Lacticaseibacillus paracasei is a food-grade lactic acid bacteria(LAB)that plays an important role in improving the human intestinal tract.However,effective gene modification tools are not reported in L.paracasei CGMC...Lacticaseibacillus paracasei is a food-grade lactic acid bacteria(LAB)that plays an important role in improving the human intestinal tract.However,effective gene modification tools are not reported in L.paracasei CGMCC4691.Here,we constructed clustered regularly interspaced short palindromic repeat(CRISPR)genetic editing tools by screening and optimizing promoters of Cas9 and sgRNA,respectively.To verify the availability of this system,single gene mutants(4691ΔAF91_08090 and 4691ΔAF91_05150)and double gene mutants(4691ΔAF91_08090ΔAF91_05150)were obtained,the editing efficiency was 54.1%and 90%after replacing P1 promoter,respectively.In addition,the addition of 5-fluorouracil(5-Fu)was lethal to wild strains compared to mutants,therefore,the gene function of mutants was verified by growth phenotype.The study realizes efficient application of the Cas9 system in L.paracasei CGMCC4691,provides a feasible optimization method for gene editing,and lays the foundation for the investigation of genetic function mechanism.展开更多
Neomycin,a crucial aminoglycoside antibiotic,is primarily biosynthesized by Streptomyces fradiae through fermentation.Its widespread applications encompass disease management in crops,treatment of bacterial infections...Neomycin,a crucial aminoglycoside antibiotic,is primarily biosynthesized by Streptomyces fradiae through fermentation.Its widespread applications encompass disease management in crops,treatment of bacterial infections in respiratory and gastrointestinal tracts,among other domains,leading to substantial market demand.Increasing evidence underscores the pivotal role of transcription factors in microbial metabolic regulation,orchestrating the coordinated expression of multiple genes in specific pathways.This orchestration holds the potential to enhance engineered microbial strains,thereby facilitating the precise and efficient synthesis of neomycin.Leveraging transcriptomic analyses of the wild-type strain SF-1 and the mutation-derived high-yield strain SF-2,this study identified significant variations in the expression levels of seven transcription factors.By constructing recombinant strains overexpressing these seven transcription factors,the optimal factor NecR,influencing neomycin production,was pinpointed.Further,promoter optimization was employed to augment neomycin synthesis.Under shaken flask cultivation conditions,the titer of neomycin B reached 11,546 U/mL,marking a 23%enhancement over the mutation-derived high-yield strain SF-2.The in vivo fluorescence reporter gene characterization using EMSA binding revealed that NecR can bind to the promoter region of neoS,thereby enhancing the transcriptional levels of neoS,subsequently promoting neomycin synthesis.This investigation not only furnishes pivotal insights for the construction of high-yield neomycin-producing strains but also elucidates the central role of transcription factors in microbial metabolic regulation.This revelation is poised to offer novel avenues and strategies in the realm of microbial metabolic engineering,holding promise for significant breakthroughs in antibiotic production and other bioproduct synthesis domains.展开更多
The low-expression level of lactoferrin(LF)in the production process poses a significant challenge.This study aimed to effi-ciently express bovine lactoferrin(BLF)using Pichia pastoris GS115 as the expression host and...The low-expression level of lactoferrin(LF)in the production process poses a significant challenge.This study aimed to effi-ciently express bovine lactoferrin(BLF)using Pichia pastoris GS115 as the expression host and PIC9K as the recombinant vector.Optimization strategies included codon usage,promoter selection,and fermentation conditions.The blf gene was optimized for P.pastoris GS115 bias,resulting in the construction of the recombinant vector pPIC9K-UBLF1-3 controlled by the AOX1 promoter.SDS-PAGE analysis revealed soluble and efficient expression of ublf3 in P.pastoris GS115,with a molecular mass of approximately 76 kDa.The transformant P.pastoris GS115/pGAP9K-UBLF3-4 resistant at 4 mg·mL^(−1)G418,exhibited a ublf3 gene copy number of 5.88 through high-copy screening.Optimal expression conditions of recombi-nant UBLF were determined as 24℃,pH 5.0 and 220 r·min^(−1)through fermentation condition optimization.Under these con-ditions,recombinant UBLF production reached 40.62 mg·L^(−1).The yield of recombinant UBLF was reached 824.93 mg·L^(−1)through high-density fermentation.Antibacterial assay demonstrated the efficacy of recombinant UBLF against Escherichia coli JM109 and Staphylococcus aureus CGMCC 1.282.This study successfully achieved the efficient heterologous expression of recombinant UBLF in P.pastoris GS115,providing valuable insight for industrial production and the potential develop-ment of natural antibacterial agents.展开更多
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23020202。
文摘Accounting for the gains and losses of ecological assets holds scientific significance in sustaining human well-being.Based on related research on ecological assets,we established a county-scale ecological asset accounting technology system by analyzing the temporal and spatial variations of county-level ecological assets in China from 1990 to 2018 and clarified the factors which caused the gains and losses of ecological assets.On these bases,optimization and promotion pathways were proposed.The results show that the number of counties dominated by farmland and forest ecological resources accounted for about 45%and 37%of the total counties,respectively.From 1990 to 2018,the quality of county-level ecological stock assets showed an increasing trend,while the water conservation volume decreased in nearly 70%of the counties.The number of counties with the gains(47%)and losses(37%)of ecological flow assets demonstrated spatial patterns which showed the same segmentation characteristics as the“Hu Huanyong Line”,that is,the counties in the vastness of northwest China experienced significant gains,while decreases were widespread in eastern and southern China.The change of ecological assets in more than 70%of the counties was driven by climate change and human activities.The average degree of impact of human activities driving the ecological asset gains in counties was about 80%,while that of climate change causing the ecological asset losses was about 60%.According to various ecological resource types,gain and loss status,and its driving factors,counties in China can be classified into five types:climate change mitigation,climate change adaptation,ecological resources restoration,ecological resources protection,and ecological resources management.Our results indicate that differentiated optimization and promotion pathways can be adopted to achieve desired ecological asset gains.
基金supported by the National Natural Science Foundation of China(32272361)National Science Fundation for Distinguished Young Scholars(32025029).
文摘Lacticaseibacillus paracasei is a food-grade lactic acid bacteria(LAB)that plays an important role in improving the human intestinal tract.However,effective gene modification tools are not reported in L.paracasei CGMCC4691.Here,we constructed clustered regularly interspaced short palindromic repeat(CRISPR)genetic editing tools by screening and optimizing promoters of Cas9 and sgRNA,respectively.To verify the availability of this system,single gene mutants(4691ΔAF91_08090 and 4691ΔAF91_05150)and double gene mutants(4691ΔAF91_08090ΔAF91_05150)were obtained,the editing efficiency was 54.1%and 90%after replacing P1 promoter,respectively.In addition,the addition of 5-fluorouracil(5-Fu)was lethal to wild strains compared to mutants,therefore,the gene function of mutants was verified by growth phenotype.The study realizes efficient application of the Cas9 system in L.paracasei CGMCC4691,provides a feasible optimization method for gene editing,and lays the foundation for the investigation of genetic function mechanism.
基金financially supported by National Natural Science Foundations of China(No.32300059)Key research and development projects and achievement transformation projects of Wuhu(Grant No.2023YF096)+1 种基金Scientific Research Start-up Fund for Introduced Talents of Anhui Polytechnic University(2022YOO068)Natural Science Research Project of Colleges and Universities in Anhui Province(Grant 2022AH050971)。
文摘Neomycin,a crucial aminoglycoside antibiotic,is primarily biosynthesized by Streptomyces fradiae through fermentation.Its widespread applications encompass disease management in crops,treatment of bacterial infections in respiratory and gastrointestinal tracts,among other domains,leading to substantial market demand.Increasing evidence underscores the pivotal role of transcription factors in microbial metabolic regulation,orchestrating the coordinated expression of multiple genes in specific pathways.This orchestration holds the potential to enhance engineered microbial strains,thereby facilitating the precise and efficient synthesis of neomycin.Leveraging transcriptomic analyses of the wild-type strain SF-1 and the mutation-derived high-yield strain SF-2,this study identified significant variations in the expression levels of seven transcription factors.By constructing recombinant strains overexpressing these seven transcription factors,the optimal factor NecR,influencing neomycin production,was pinpointed.Further,promoter optimization was employed to augment neomycin synthesis.Under shaken flask cultivation conditions,the titer of neomycin B reached 11,546 U/mL,marking a 23%enhancement over the mutation-derived high-yield strain SF-2.The in vivo fluorescence reporter gene characterization using EMSA binding revealed that NecR can bind to the promoter region of neoS,thereby enhancing the transcriptional levels of neoS,subsequently promoting neomycin synthesis.This investigation not only furnishes pivotal insights for the construction of high-yield neomycin-producing strains but also elucidates the central role of transcription factors in microbial metabolic regulation.This revelation is poised to offer novel avenues and strategies in the realm of microbial metabolic engineering,holding promise for significant breakthroughs in antibiotic production and other bioproduct synthesis domains.
基金supported by the National Key Research and Development Program of China(2023YFA0914500)the National Science Foundation of China(32271487)+1 种基金the National First-class Discipline Program of Light Industry Technology and Engineering(LITE2018-12)the Program of Introducing Talents of Discipline to Universities(111-2-06).
文摘The low-expression level of lactoferrin(LF)in the production process poses a significant challenge.This study aimed to effi-ciently express bovine lactoferrin(BLF)using Pichia pastoris GS115 as the expression host and PIC9K as the recombinant vector.Optimization strategies included codon usage,promoter selection,and fermentation conditions.The blf gene was optimized for P.pastoris GS115 bias,resulting in the construction of the recombinant vector pPIC9K-UBLF1-3 controlled by the AOX1 promoter.SDS-PAGE analysis revealed soluble and efficient expression of ublf3 in P.pastoris GS115,with a molecular mass of approximately 76 kDa.The transformant P.pastoris GS115/pGAP9K-UBLF3-4 resistant at 4 mg·mL^(−1)G418,exhibited a ublf3 gene copy number of 5.88 through high-copy screening.Optimal expression conditions of recombi-nant UBLF were determined as 24℃,pH 5.0 and 220 r·min^(−1)through fermentation condition optimization.Under these con-ditions,recombinant UBLF production reached 40.62 mg·L^(−1).The yield of recombinant UBLF was reached 824.93 mg·L^(−1)through high-density fermentation.Antibacterial assay demonstrated the efficacy of recombinant UBLF against Escherichia coli JM109 and Staphylococcus aureus CGMCC 1.282.This study successfully achieved the efficient heterologous expression of recombinant UBLF in P.pastoris GS115,providing valuable insight for industrial production and the potential develop-ment of natural antibacterial agents.
