The response patterns of microbial functional genes involved in biogeochemical cycles to cadaver decay is a central topic of recent environmental sciences.However,the response mechanisms and pathways of the functional...The response patterns of microbial functional genes involved in biogeochemical cycles to cadaver decay is a central topic of recent environmental sciences.However,the response mechanisms and pathways of the functional genes associated with the carbon(C)and nitrogen(N)cycling to cadaveric substances such as cadaverine and putrescine remain unclear.This study explored the variation of functional genes associated with C fixation,C degradation and N cycling and their influencing factors under cadaverine,putrescine and mixed treatments.Our results showed only putrescine significantly increased the alpha diversity of C fixation genes,while reducing the alpha diversity of N cycling genes in sediment.For the C cycling,the mixed treatment significantly decreased the total abundance of reductive acetyl-CoA pathway genes(i.e.,acsB and acsE)and lig gene linked to lignin degradation in water,while only significantly increasing the hydroxypropionate-hydroxybutylate cycle(i.e.,accA)gene abundance in sediment.For the N cycling,mixed treatment significantly decreased the abundance of the nitrification(i.e.,amoB),denitrification(i.e.,nirS3)genes in water and the assimilation pathway gene(i.e.,gdhA)in sediment.Environmental factors(i.e.,total carbon and total nitrogen)were all negatively associated with the genes of C and N cycling.Therefore,cadaverine and putrescine exposure may inhibit the pathway in C fixation and N cycling,while promoting C degradation.These findings can offer some new insight for the management of amine pollution caused by animal cadavers.展开更多
Intelligent chemical sensors have been extensively used in food safety and environmental assessment,while limited sensitivity and homogeneity bring about huge obstacles to their practical application.Herein,novel ioni...Intelligent chemical sensors have been extensively used in food safety and environmental assessment,while limited sensitivity and homogeneity bring about huge obstacles to their practical application.Herein,novel ionically conductive sensitive materials were elaborately designed based on metal ion decorated graphene oxide(GO)via a facile and general in-situ spin-coating strategy,where the abundant functional groups(-OH and-COOH)of GO layer could provide natural binding sites for various bivalent metal cations(such as Cu^(2+),Ni^(2+),Zn^(2+),Co^(2+),and Mg^(2+))through coordination and electrostatic inter-action.The intercalated metal cations on the layered GO nanosheets can be regarded as charge carriers and complexation with targeted gas(cadaverine,Cad),which is a typical metabolites production and food degradants.By contrast,the designed GO@Cu(Ⅱ)sensor exhibited the optimal sensing performance toward Cad molecules at room temperature,including ultra-low detection limit(ca.3 nL),excellent sensitivity,and rapid low concentration detection rate(only 16 s).Interestingly,the sensor exhibited an irreversible and specific response toward Cad,while it showed a transient and reversible response to other interfering gases,implying its outstanding selectivity.In addition,the GO@Cu(Ⅱ)sensor enabled real-time monitoring of the decay progression of cheese,and it exhibited great potential for large-scale production via its excellent homogeneity.It provides an efficient approach to tailoring intelligent chemical sensors for real-time food safety monitoring and human health warning.展开更多
Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various appli...Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various applications, especially as an important monomer for bio-based polyamides. Cadaverine-based polyamide PA 5X has broad application prospects owing to its environmentally friendly characteristics and exceptional performance in water absorption and dimensional stability. In this review, we summarize recent findings on the biosynthesis, metabolism, and physiological function of cadaverine in bacteria, with a focus on the regu- latory mechanism of cadaverine synthesis in Escherichia coil （E. coli）. We also describe recent developments in bacterial production of cadaverine by direct fermentation and whole-cell bioconversion, and recent approaches for the separation and purification of cadaverine. In addition, we present an overview of the ap- plication of cadaverine in the synthesis of completely bio-based polyamides. Finally. we provide an outlook and suggest future developments to advance the production of cadaverine from renewable resources.展开更多
Cadaverine is an important C5 platform chemical with a wide range of industrial applications.However,the cadaverine inhibition on the fermenting strain limited its industrial efficiency of the strain.In this study,we ...Cadaverine is an important C5 platform chemical with a wide range of industrial applications.However,the cadaverine inhibition on the fermenting strain limited its industrial efficiency of the strain.In this study,we report an engineered Escherichia coli strain with high cadaverine productivity that was generated by developing a robust host coupled with metabolic engineering to mitigate cadaverine inhibition.First,a lysine producing E.coli was treated with a combination of radiation(ultraviolet and visible spectrum)and ARTP(atmospheric and room temperature plasma)mutagenesis to obtain a robust host with high cadaverine tolerance.Three mutant targets including HokD,PhnI and PuuR are identified for improved cadaverine tolerance.Further transcriptome analysis suggested that cadaverine suppressed the synthesis of ATP and lysine precursor.Accordingly,the related genes involved in glycolysis and lysine precursor,as well as cadaverine exporter was engineered to release the cadaverine inhibition.The final engineered strain was fed-batch cultured and a titer of 58.7 g/L cadaverine was achieved with a yield of 0.396 g/g,both of which were the highest level reported to date in E.coli.The bio-based cadaverine was purified to>99.6%purity,and successfully used for the synthesis of polyurethane precursor 1,5-pentamethylene diisocyanate(PDI)through the approach of carbamate decomposition.展开更多
Cadaverine is the key monomer for the synthesis of nylon 5X.Efficient and alkaline stable lysine decarboxylases are highly desirable for cadaverine production as the reaction pH increasing from 6.3 to 8.5.However,the ...Cadaverine is the key monomer for the synthesis of nylon 5X.Efficient and alkaline stable lysine decarboxylases are highly desirable for cadaverine production as the reaction pH increasing from 6.3 to 8.5.However,the most studied lysine decarboxylase CadA(E.coli)lost almost all activity at pH 8.0,which is the foremost challenge for the industrial-cadaverine production.In this study,we first found that the Na^(+)-microenvironment significantly improved the alkaline stability of the disulfide engineered lysine decarboxylaseΔLdcEt3(P233C/L628C)(half-life 362 h),compared to the conventional buffer(half-life 0.66 h)at pH 8.0.Meanwhile,the whole-cell conversion efficiency of the industrial-grade L-lysine withΔLdcEt3 could reach up to 99%in 2 h in the fermenter.Experi-mental investigation and molecular dynamics confirmed that Na^(+)-microenvironment could improve active-aggregation state and affect secondary structure ofΔLdcEt3.Therefore,Na^(+)-microenvironment stabilizesΔLdcEt3 providing a great potential industrial application for high-level cadaverine production.展开更多
Sanchuan ham is appreciated in Yunnan Province,China,for its characteristic flavor and taste,while the microbial community structure and biogenic amines content remain unclear during fermentation processes.In this stu...Sanchuan ham is appreciated in Yunnan Province,China,for its characteristic flavor and taste,while the microbial community structure and biogenic amines content remain unclear during fermentation processes.In this study,we explored the physicochemical property,biogenic amines concentration and microbial diversity of external and internal Sanchuan ham by high-throughput sequencing during the processing of Sanchuan ham.Results showed that the nitrite remained at a stable level of 0.15 mg/kg which was significantly lower than the national health standard safety level of 20 mg/kg.In addition,compared with fresh hams,the content of total free amino acids in ripe Sanchuan ham has grown 14 folds;sour and bitter were the main tastes of Sanchuan ham.Notably,the concentration of cadaverine was the highest of all biogenic amines during the entire fermentation period.At the bacterial phyla level,Firmicutes and Actinobacteria were the two main phyla,while at the genus level,Staphylococcus was a significant strain throughout the whole fermentation.Moreover,the dry stage has a great impact on the succession change of microbial community structure.Simultaneously,the change trends and composition of bacteria in the interior have slight discrepancies with those of the exterior of Sanchuan ham.展开更多
Using cDNA-AFLP technique, a specific fragment was isolated from cucumber cultivar Changchun mici possessing chilling tolerance induced at low temperature （15℃）. This fragment, named cctr 132, could not be induced ...Using cDNA-AFLP technique, a specific fragment was isolated from cucumber cultivar Changchun mici possessing chilling tolerance induced at low temperature （15℃）. This fragment, named cctr 132, could not be induced in the chilling sensitive cucumber cultivar Beijing jietou. After recovering the fragment, sequencing and translating, the results of blastx and blastp in GenBank of NCBI indicated that CCTR132 had 88.37% identities and 100% positives with Oryza sativa putative lysine decarboxylase-like protein respectively, and PGGXGTXXE, the putative conserved domain of lysine decarboxylase family, was detected from CCTR132, suggesting the cucumber chilling tolerance during germination is related to the expression of the lysine decarboxylase gene.展开更多
The reactions of cryptotanshinone and tanshinone IIA with cadaverine and putrescine were investigated. Six new compounds, four with imidazole functional groups and two with oxazole groups, were obtained. The possibl...The reactions of cryptotanshinone and tanshinone IIA with cadaverine and putrescine were investigated. Six new compounds, four with imidazole functional groups and two with oxazole groups, were obtained. The possible reaction mechanism was proposed.展开更多
基金supported by the National Natural Science Foundation of China(No.42007026)the Medical Innovation and Development Project of Lanzhou University(No.lzuyxcx-2022-172)。
文摘The response patterns of microbial functional genes involved in biogeochemical cycles to cadaver decay is a central topic of recent environmental sciences.However,the response mechanisms and pathways of the functional genes associated with the carbon(C)and nitrogen(N)cycling to cadaveric substances such as cadaverine and putrescine remain unclear.This study explored the variation of functional genes associated with C fixation,C degradation and N cycling and their influencing factors under cadaverine,putrescine and mixed treatments.Our results showed only putrescine significantly increased the alpha diversity of C fixation genes,while reducing the alpha diversity of N cycling genes in sediment.For the C cycling,the mixed treatment significantly decreased the total abundance of reductive acetyl-CoA pathway genes(i.e.,acsB and acsE)and lig gene linked to lignin degradation in water,while only significantly increasing the hydroxypropionate-hydroxybutylate cycle(i.e.,accA)gene abundance in sediment.For the N cycling,mixed treatment significantly decreased the abundance of the nitrification(i.e.,amoB),denitrification(i.e.,nirS3)genes in water and the assimilation pathway gene(i.e.,gdhA)in sediment.Environmental factors(i.e.,total carbon and total nitrogen)were all negatively associated with the genes of C and N cycling.Therefore,cadaverine and putrescine exposure may inhibit the pathway in C fixation and N cycling,while promoting C degradation.These findings can offer some new insight for the management of amine pollution caused by animal cadavers.
基金supported by the National Natural Science Foundation of China(Nos.62074111,22105043)the Science&Technology Foundation of Shanghai(Nos.19JC1412402,20JC1415600)+2 种基金Shanghai Municipal Science and Technology Major Project(No.2021SHZDZX0100)Shanghai Municipal Commission of Science and Technology Project(No.19511132101)the support of the Fundamental Research Funds for the Central Universities
文摘Intelligent chemical sensors have been extensively used in food safety and environmental assessment,while limited sensitivity and homogeneity bring about huge obstacles to their practical application.Herein,novel ionically conductive sensitive materials were elaborately designed based on metal ion decorated graphene oxide(GO)via a facile and general in-situ spin-coating strategy,where the abundant functional groups(-OH and-COOH)of GO layer could provide natural binding sites for various bivalent metal cations(such as Cu^(2+),Ni^(2+),Zn^(2+),Co^(2+),and Mg^(2+))through coordination and electrostatic inter-action.The intercalated metal cations on the layered GO nanosheets can be regarded as charge carriers and complexation with targeted gas(cadaverine,Cad),which is a typical metabolites production and food degradants.By contrast,the designed GO@Cu(Ⅱ)sensor exhibited the optimal sensing performance toward Cad molecules at room temperature,including ultra-low detection limit(ca.3 nL),excellent sensitivity,and rapid low concentration detection rate(only 16 s).Interestingly,the sensor exhibited an irreversible and specific response toward Cad,while it showed a transient and reversible response to other interfering gases,implying its outstanding selectivity.In addition,the GO@Cu(Ⅱ)sensor enabled real-time monitoring of the decay progression of cheese,and it exhibited great potential for large-scale production via its excellent homogeneity.It provides an efficient approach to tailoring intelligent chemical sensors for real-time food safety monitoring and human health warning.
基金This work was supported by the National Key Research and Development Program （2016YFA0204300） the National Natural Science Foundation of China （21390200, 31440024） and the Tech- nology Support Program of Gansu Provincial S＆T Department, China （1304FKCE106）.
文摘Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various applications, especially as an important monomer for bio-based polyamides. Cadaverine-based polyamide PA 5X has broad application prospects owing to its environmentally friendly characteristics and exceptional performance in water absorption and dimensional stability. In this review, we summarize recent findings on the biosynthesis, metabolism, and physiological function of cadaverine in bacteria, with a focus on the regu- latory mechanism of cadaverine synthesis in Escherichia coil （E. coli）. We also describe recent developments in bacterial production of cadaverine by direct fermentation and whole-cell bioconversion, and recent approaches for the separation and purification of cadaverine. In addition, we present an overview of the ap- plication of cadaverine in the synthesis of completely bio-based polyamides. Finally. we provide an outlook and suggest future developments to advance the production of cadaverine from renewable resources.
基金This work is supported by the National Key R&D Program of China(2021YFC2100800)Key Research and Development Program(Social Development)Project of Jiangsu Province(BE2018730)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture(XTE1844 and XTB1806).
文摘Cadaverine is an important C5 platform chemical with a wide range of industrial applications.However,the cadaverine inhibition on the fermenting strain limited its industrial efficiency of the strain.In this study,we report an engineered Escherichia coli strain with high cadaverine productivity that was generated by developing a robust host coupled with metabolic engineering to mitigate cadaverine inhibition.First,a lysine producing E.coli was treated with a combination of radiation(ultraviolet and visible spectrum)and ARTP(atmospheric and room temperature plasma)mutagenesis to obtain a robust host with high cadaverine tolerance.Three mutant targets including HokD,PhnI and PuuR are identified for improved cadaverine tolerance.Further transcriptome analysis suggested that cadaverine suppressed the synthesis of ATP and lysine precursor.Accordingly,the related genes involved in glycolysis and lysine precursor,as well as cadaverine exporter was engineered to release the cadaverine inhibition.The final engineered strain was fed-batch cultured and a titer of 58.7 g/L cadaverine was achieved with a yield of 0.396 g/g,both of which were the highest level reported to date in E.coli.The bio-based cadaverine was purified to>99.6%purity,and successfully used for the synthesis of polyurethane precursor 1,5-pentamethylene diisocyanate(PDI)through the approach of carbamate decomposition.
基金supported by the National Natural Science Foundation of China (grant number 22078346)Beijing Nova Program of Science and Technology (Z201100006820141)+4 种基金Innovation Academy for Green Manufacture, CAS (IAGM2020C19)Natural Science Foundation of Beijing (2204097)Henan Key Research and Development Project (202102210046)Hebei Provincial Natural Science Foundation (B2020103010)the CAS Pioneer Hundred Program。
文摘Cadaverine is the key monomer for the synthesis of nylon 5X.Efficient and alkaline stable lysine decarboxylases are highly desirable for cadaverine production as the reaction pH increasing from 6.3 to 8.5.However,the most studied lysine decarboxylase CadA(E.coli)lost almost all activity at pH 8.0,which is the foremost challenge for the industrial-cadaverine production.In this study,we first found that the Na^(+)-microenvironment significantly improved the alkaline stability of the disulfide engineered lysine decarboxylaseΔLdcEt3(P233C/L628C)(half-life 362 h),compared to the conventional buffer(half-life 0.66 h)at pH 8.0.Meanwhile,the whole-cell conversion efficiency of the industrial-grade L-lysine withΔLdcEt3 could reach up to 99%in 2 h in the fermenter.Experi-mental investigation and molecular dynamics confirmed that Na^(+)-microenvironment could improve active-aggregation state and affect secondary structure ofΔLdcEt3.Therefore,Na^(+)-microenvironment stabilizesΔLdcEt3 providing a great potential industrial application for high-level cadaverine production.
基金funded by National Natural Science Foundation of China(31460445)Science and Technology Talents and Platform Program of Yunnan Province,No.202105AF150049Yunnan University Key Laboratory of Food Microbial Resources and Utilization(Yunjiaofa[2018]No.135)。
文摘Sanchuan ham is appreciated in Yunnan Province,China,for its characteristic flavor and taste,while the microbial community structure and biogenic amines content remain unclear during fermentation processes.In this study,we explored the physicochemical property,biogenic amines concentration and microbial diversity of external and internal Sanchuan ham by high-throughput sequencing during the processing of Sanchuan ham.Results showed that the nitrite remained at a stable level of 0.15 mg/kg which was significantly lower than the national health standard safety level of 20 mg/kg.In addition,compared with fresh hams,the content of total free amino acids in ripe Sanchuan ham has grown 14 folds;sour and bitter were the main tastes of Sanchuan ham.Notably,the concentration of cadaverine was the highest of all biogenic amines during the entire fermentation period.At the bacterial phyla level,Firmicutes and Actinobacteria were the two main phyla,while at the genus level,Staphylococcus was a significant strain throughout the whole fermentation.Moreover,the dry stage has a great impact on the succession change of microbial community structure.Simultaneously,the change trends and composition of bacteria in the interior have slight discrepancies with those of the exterior of Sanchuan ham.
基金This work was partially supported by grants from National Hi-11ech R&D Program(2004241120)the National Natural Science Foundation of China(30470120)Ministry of Agriculture Vegetable Genetic and Physiological Key Laboratory.
文摘Using cDNA-AFLP technique, a specific fragment was isolated from cucumber cultivar Changchun mici possessing chilling tolerance induced at low temperature （15℃）. This fragment, named cctr 132, could not be induced in the chilling sensitive cucumber cultivar Beijing jietou. After recovering the fragment, sequencing and translating, the results of blastx and blastp in GenBank of NCBI indicated that CCTR132 had 88.37% identities and 100% positives with Oryza sativa putative lysine decarboxylase-like protein respectively, and PGGXGTXXE, the putative conserved domain of lysine decarboxylase family, was detected from CCTR132, suggesting the cucumber chilling tolerance during germination is related to the expression of the lysine decarboxylase gene.
基金the Guangzhou City Science Foundation(2002 Z1-E5011)Guangdong Provincial Science Foundation of China(2003 C104014)for the financial support.
文摘The reactions of cryptotanshinone and tanshinone IIA with cadaverine and putrescine were investigated. Six new compounds, four with imidazole functional groups and two with oxazole groups, were obtained. The possible reaction mechanism was proposed.
