Erwinia persicina is a bacterium that has been known to produce secondary metabolites,such as andrimid,pink pigment,and exopolysaccharides,and to infect more than twenty plant species.However,traditional gene manipula...Erwinia persicina is a bacterium that has been known to produce secondary metabolites,such as andrimid,pink pigment,and exopolysaccharides,and to infect more than twenty plant species.However,traditional gene manipulation methods have been hindered by the inefficient of suicide plasmid-mediated genome editing.In this study,we describe the successful application of the CRISPR-Cas9 system in E.persicina.Efficient genome editing was achieved by substituting the native gRNA promoter with J23119 in a single-plasmid system(pRed_Cas9_ΔpoxB)and optimizing the gRNA design.The use of double gRNAs led to the deletion of a 42 kb genomic fragment,and the incorporation of a sacB screening marker facilitated iterative knockouts.Additionally,a 22 kb plasmid containing a self-resistance gene was conjugally transferred into E.persicina,resulting in the insertion of a 6.4 kb fragment with 100%efficiency.Furthermore,we demonstrated the expression of shinorine,an anti-UV compound,within the E.persicina chassis.This study establishes E.persicina as a promising chassis for synthetic biology and provides a model for gene-editing systems in non-model microorganisms.展开更多
【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征,【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础,选取代表性水文系列,结合入库污染负荷计算模型,构建了污染负荷量及入库强度的面源污染关...【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征,【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础,选取代表性水文系列,结合入库污染负荷计算模型,构建了污染负荷量及入库强度的面源污染关键源区识别技术流程,并在数据条件较为完备的沙河水库流域进行验证。【结果】结果表明:沙河水库流域总氮(Total Nitrogen,TN)入库负荷总量为198.34 t/a,面源污染占比为86.53%,流域内茶园TN负荷量贡献率最大,占比为23.84%;TN负荷量在丰水年和特丰水年比枯水年上升58.06%和289.09%,在年内丰水期TN月均负荷量比平水期和枯水期分别高出75.24%和372.51%;河道削减TN负荷量为33.58 t/a,削减比例为14.48%;子流域TN入库产污强度变化范围为0.36~4.73 t/km^(2)。面源污染排放入库低值区主要位于流域南部,高值区主要位于近库区域,沙河西和沙河东控制分区单位面积TN入库强度显著高于流域南部。【结论】针对高产污地类、高产污区域及高产污时段应提高面源污染防控力度;建立的技术流程可有效识别和科学解析流域面源污染关键源区,为流域水环境开展面源污染防治和生态适应性开发提供一定技术支持,使相关工作开展更加有的放矢。展开更多
目的探讨合肥市空气O_(3)暴露对儿童呼吸系统疾病急诊就诊量影响。方法收集合肥市某儿童医院2017年1月1日至2019年12月31日逐日儿童急诊就诊资料、空气污染物监测资料和气象资料。基于分布滞后非线性模型(distributed lag non-linear mo...目的探讨合肥市空气O_(3)暴露对儿童呼吸系统疾病急诊就诊量影响。方法收集合肥市某儿童医院2017年1月1日至2019年12月31日逐日儿童急诊就诊资料、空气污染物监测资料和气象资料。基于分布滞后非线性模型(distributed lag non-linear model,DLNM)评估不同质量浓度O_(3)对儿童呼吸系统疾病急诊就诊量的影响,模型中调整气象因素、时间趋势和星期几等变量。结果研究期间共纳入因儿童呼吸系统疾病急诊就诊153995人次,儿童呼吸系统疾病急诊就诊量随O_(3)质量浓度上升而增加。相对于60μg/m^(3),O_(3)质量浓度在P_(25)、P_(50)、P_(75)和P_(95)时儿童呼吸系统疾病急诊就诊量单日滞后效应相对危险度(relative risk,RR)及95%置信区间(confidence interval,CI)分别为1.004(1.000~1.008)、1.031(1.016~1.045)、1.062(1.037~1.087)和1.084(1.053~1.115),累积滞后效应RR(95%CI)分别为1.009(1.001~1.013)、1.082(1.046~1.119)、1.185(1.112~1.263)和1.244(1.159~1.336)。O_(3)质量浓度对男孩和女孩呼吸系统疾病急诊就诊量的影响差异无统计学意义。不同疾病中,P_(25)至P_(95)浓度范围O_(3)对急性上呼吸感染、急性下呼吸道感染及肺炎急诊就诊量影响的单日滞后效应RR分别为1.006~1.072、1.006~1.058和1.005~1.060,累积滞后效应RR分别为1.009~1.223、1.003~1.359和1.017~1.450。结论合肥市空气O_(3)质量浓度升高可能会增加儿童呼吸系统疾病发病风险。展开更多
基金funding from the Hundred Talents Program of the Chinese Academy of Sciences to LZ(E3J56201).
文摘Erwinia persicina is a bacterium that has been known to produce secondary metabolites,such as andrimid,pink pigment,and exopolysaccharides,and to infect more than twenty plant species.However,traditional gene manipulation methods have been hindered by the inefficient of suicide plasmid-mediated genome editing.In this study,we describe the successful application of the CRISPR-Cas9 system in E.persicina.Efficient genome editing was achieved by substituting the native gRNA promoter with J23119 in a single-plasmid system(pRed_Cas9_ΔpoxB)and optimizing the gRNA design.The use of double gRNAs led to the deletion of a 42 kb genomic fragment,and the incorporation of a sacB screening marker facilitated iterative knockouts.Additionally,a 22 kb plasmid containing a self-resistance gene was conjugally transferred into E.persicina,resulting in the insertion of a 6.4 kb fragment with 100%efficiency.Furthermore,we demonstrated the expression of shinorine,an anti-UV compound,within the E.persicina chassis.This study establishes E.persicina as a promising chassis for synthetic biology and provides a model for gene-editing systems in non-model microorganisms.
文摘【目的】为厘清流域面源污染源结构、精细化解析面源污染负荷时空特征,【方法】以SWAT(Soil and Water Assessment Tool)流域面源污染模型为基础,选取代表性水文系列,结合入库污染负荷计算模型,构建了污染负荷量及入库强度的面源污染关键源区识别技术流程,并在数据条件较为完备的沙河水库流域进行验证。【结果】结果表明:沙河水库流域总氮(Total Nitrogen,TN)入库负荷总量为198.34 t/a,面源污染占比为86.53%,流域内茶园TN负荷量贡献率最大,占比为23.84%;TN负荷量在丰水年和特丰水年比枯水年上升58.06%和289.09%,在年内丰水期TN月均负荷量比平水期和枯水期分别高出75.24%和372.51%;河道削减TN负荷量为33.58 t/a,削减比例为14.48%;子流域TN入库产污强度变化范围为0.36~4.73 t/km^(2)。面源污染排放入库低值区主要位于流域南部,高值区主要位于近库区域,沙河西和沙河东控制分区单位面积TN入库强度显著高于流域南部。【结论】针对高产污地类、高产污区域及高产污时段应提高面源污染防控力度;建立的技术流程可有效识别和科学解析流域面源污染关键源区,为流域水环境开展面源污染防治和生态适应性开发提供一定技术支持,使相关工作开展更加有的放矢。
文摘针对数值模拟时常将质子交换膜电解池(PEMEC)视为等温状态的问题,建立了稳态、三维、两相、非等温的PEMEC单流道模型,研究了等温模型和非等温模型对模拟结果的影响,分析了PEMEC的产热规律和温度分布.结果表明:非等温模型能更准确模拟PEMEC的工作性能;相同工作电压下,非等温模型计算得到的电流密度值高于等温模型,且工作电压越高,二者相差越大;工作电压高于1.4 V时,总产热量呈抛物线趋势增加,阳极催化层(ACL)、阴极催化层(CCL)、质子交换膜(PEM)的产热量占比超过98%,ACL的产热密度高于PEM和CCL;与仅阳极侧供水相比,当工作电压为2.2 V时,采用阴极顺流和逆流供水可将膜电极(MEA)的温度均匀性从0.44%分别降至0.16%和0.14%,极限温差从12.25 K降至4.13和3.69 K.
