The microbial production of D-lysine to replace chemical approach has gained great interest with the rising concerns over the environment.Here,we employed recombinant E.coli strain BL21-LYR with lysine racemase and st...The microbial production of D-lysine to replace chemical approach has gained great interest with the rising concerns over the environment.Here,we employed recombinant E.coli strain BL21-LYR with lysine racemase and strain BL-22A-RB-YB with L-lysine monooxygenase and 5-aminovaleramide amidohydrolase to establish a two-strain coupling whole-cell bioconversion system for D-lysine production from L-lysine.To improve the optical purity of D-lysine,the optimal reaction condition for resolution of DL-lysine after the racemization was investigated.The specificity of BL-22A-RB-YB for L^-lysine and the effects of reaction condition on bioconversion efficiency of whole-cell were accordingly determined.Under the optimal condition,a maximum 53.5 g·L^-1 D-lysine and 48.2 g·L^-15-AVA were obtained with yield of 47.4%and 42.3%,respectively,by the microbial racemization and asymmetric degradation process.The final D-lysine enantiomeric excess was over 99%.Meanwhile,a valuable compound 5-aminovaleric acid was synthesized with the production of D-lysine,indicating the economic feasibility of the two-strain coupling system.展开更多
We propose a malaria model involving the sensitive and resistant strains,which is described by reaction-diffusion equations.The model reflects the scenario that the vector and host populations disperse with distinct d...We propose a malaria model involving the sensitive and resistant strains,which is described by reaction-diffusion equations.The model reflects the scenario that the vector and host populations disperse with distinct diffusion rates,susceptible individuals or vectors cannot be infected by both strains simultaneously,and the vector population satisfies the logistic growth.Our main purpose is to get a threshold type result on the model,especially the interaction effect of the two strains in the presence of spatial structure.To solve this issue,the basic reproduction number(BRN)R_(0)^(i)and invasion reproduction number(IRN)R_(0)^(i)of each strain(i=1 and 2 are for the sensitive and resistant strains,respectively)are defined.Furthermore,we investigate the influence of the diffusion rates of populations and vectors on BRNs and IRNs.展开更多
目的:探讨基于左心室压力-应变环(pressure-strain loop,PSL)的二维左心室整体纵向应变(two-dimensional left ventricular global longitudinal strain,2D-GLS)、心肌做功参数预测急性心肌梗死(acute myocardial infarction,AMI)患者PC...目的:探讨基于左心室压力-应变环(pressure-strain loop,PSL)的二维左心室整体纵向应变(two-dimensional left ventricular global longitudinal strain,2D-GLS)、心肌做功参数预测急性心肌梗死(acute myocardial infarction,AMI)患者PCI术后心肌灌注不良的价值。方法:收集117例2023年4月至2024年4月,在华中科技大学同济医学院附属梨园医院接受PCI术治疗的AMI患者的,根据术后是否发生心肌灌注不良将其分为心肌灌注不良组(n=26)及无心肌灌注不良组(n=91),并分析其PCI术前2D-GLS参数[心内膜下心肌节段整体纵向应变(global longitudinal strain of subendocardial myocardial segmen,GLSendo)、中层心肌节段整体纵向应变(global longitudinal strain of middle myocardial segment,GLSmid)、心外膜下心肌节段整体纵向应变(global longitudinal strain ofsubepicardialmyocardialsegment,GLSepi)]及心肌做功参数[整体有用功(globalconstructive work,GCW)、整体做功功率(global work efficiency,GWE)、整体做功指数(global work index,GWI)及整体无用功(global wasted work GWW)]预测AMI患者PCI术后发生心肌灌注不良的价值。结果:(1)常规超声显示,两组患者LVEDD、左心室舒张末期容积、左心室收缩末期容积及LVEF比较无明显差异(P>0.05);(2)二维应变成像显示,心肌灌注不良组患者GLSendo、GLSmid、GLSepi均较无心肌灌注不良组低(P<0.05);(3)二维应变成像显示,心肌灌注不良组患者GWW较无心肌灌注不良组高(P<0.05),GCW、GWE、GWI均较无心肌灌注不良组低(P<0.05);(4)AMI患者PCI术前GLSendo、GLSmid、GLSepi、GWW、GCW、GWE、GWI预测其PCI术后心肌灌注不良的效能较高,其中GWI的预测效能最高,其Youden指数最大时(0.747),预测PCI术后心肌灌注不良曲线下面积(AUC)为0.849,敏感度为92.8%,特异度为82.4%。结论:AMI心肌灌注不良患者PCI术前GWW异常增高,GLSendo、GLSmid、GLSepi、GCW、GWE、GWI异常降低,均可作为预测该类患者PCI术后心肌灌注不良的有效指标,其中GWI预测效能最高。展开更多
基金financial supports from the National Natural Science Foundation of China(Grant No.21908099)the National Key Research and Development Program of China(Grant No.2016YFA0204300)+2 种基金Key Research and Development Program(Social Development)Project Jiangsu Province(Grant No.BE2018730)the Natural Science Research Projects of Colleges and Universities in Jiangsu Province(Grant No.18KJB530009)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture(Grant No.XTB1802,Grant No.XTE1846)。
文摘The microbial production of D-lysine to replace chemical approach has gained great interest with the rising concerns over the environment.Here,we employed recombinant E.coli strain BL21-LYR with lysine racemase and strain BL-22A-RB-YB with L-lysine monooxygenase and 5-aminovaleramide amidohydrolase to establish a two-strain coupling whole-cell bioconversion system for D-lysine production from L-lysine.To improve the optical purity of D-lysine,the optimal reaction condition for resolution of DL-lysine after the racemization was investigated.The specificity of BL-22A-RB-YB for L^-lysine and the effects of reaction condition on bioconversion efficiency of whole-cell were accordingly determined.Under the optimal condition,a maximum 53.5 g·L^-1 D-lysine and 48.2 g·L^-15-AVA were obtained with yield of 47.4%and 42.3%,respectively,by the microbial racemization and asymmetric degradation process.The final D-lysine enantiomeric excess was over 99%.Meanwhile,a valuable compound 5-aminovaleric acid was synthesized with the production of D-lysine,indicating the economic feasibility of the two-strain coupling system.
基金This research was partially supported by the National Natural Science Foundation of China(Nos.12071115,11871179)the Heilongjiang Natural Science Funds for Distinguished Young Scholar(No.JQ2023A005),and Heilongjiang Provincial Key Laboratory of the Theory and Computation of Complex Systems(JW)NSERC of Canada(No.RGPIN-2019-05892)(YC).
文摘We propose a malaria model involving the sensitive and resistant strains,which is described by reaction-diffusion equations.The model reflects the scenario that the vector and host populations disperse with distinct diffusion rates,susceptible individuals or vectors cannot be infected by both strains simultaneously,and the vector population satisfies the logistic growth.Our main purpose is to get a threshold type result on the model,especially the interaction effect of the two strains in the presence of spatial structure.To solve this issue,the basic reproduction number(BRN)R_(0)^(i)and invasion reproduction number(IRN)R_(0)^(i)of each strain(i=1 and 2 are for the sensitive and resistant strains,respectively)are defined.Furthermore,we investigate the influence of the diffusion rates of populations and vectors on BRNs and IRNs.
文摘目的:探讨基于左心室压力-应变环(pressure-strain loop,PSL)的二维左心室整体纵向应变(two-dimensional left ventricular global longitudinal strain,2D-GLS)、心肌做功参数预测急性心肌梗死(acute myocardial infarction,AMI)患者PCI术后心肌灌注不良的价值。方法:收集117例2023年4月至2024年4月,在华中科技大学同济医学院附属梨园医院接受PCI术治疗的AMI患者的,根据术后是否发生心肌灌注不良将其分为心肌灌注不良组(n=26)及无心肌灌注不良组(n=91),并分析其PCI术前2D-GLS参数[心内膜下心肌节段整体纵向应变(global longitudinal strain of subendocardial myocardial segmen,GLSendo)、中层心肌节段整体纵向应变(global longitudinal strain of middle myocardial segment,GLSmid)、心外膜下心肌节段整体纵向应变(global longitudinal strain ofsubepicardialmyocardialsegment,GLSepi)]及心肌做功参数[整体有用功(globalconstructive work,GCW)、整体做功功率(global work efficiency,GWE)、整体做功指数(global work index,GWI)及整体无用功(global wasted work GWW)]预测AMI患者PCI术后发生心肌灌注不良的价值。结果:(1)常规超声显示,两组患者LVEDD、左心室舒张末期容积、左心室收缩末期容积及LVEF比较无明显差异(P>0.05);(2)二维应变成像显示,心肌灌注不良组患者GLSendo、GLSmid、GLSepi均较无心肌灌注不良组低(P<0.05);(3)二维应变成像显示,心肌灌注不良组患者GWW较无心肌灌注不良组高(P<0.05),GCW、GWE、GWI均较无心肌灌注不良组低(P<0.05);(4)AMI患者PCI术前GLSendo、GLSmid、GLSepi、GWW、GCW、GWE、GWI预测其PCI术后心肌灌注不良的效能较高,其中GWI的预测效能最高,其Youden指数最大时(0.747),预测PCI术后心肌灌注不良曲线下面积(AUC)为0.849,敏感度为92.8%,特异度为82.4%。结论:AMI心肌灌注不良患者PCI术前GWW异常增高,GLSendo、GLSmid、GLSepi、GCW、GWE、GWI异常降低,均可作为预测该类患者PCI术后心肌灌注不良的有效指标,其中GWI预测效能最高。
