【目的】研究水稻防御反应和叶片早衰相关基因的分子机理。【方法】从粳稻武运粳7号诱变库中筛选出一个类病变早衰突变体lmes7(lesion mimic and early senescence 7)。调查统计了该突变体的主要农艺性状,对其叶片中的光合色素含量进行...【目的】研究水稻防御反应和叶片早衰相关基因的分子机理。【方法】从粳稻武运粳7号诱变库中筛选出一个类病变早衰突变体lmes7(lesion mimic and early senescence 7)。调查统计了该突变体的主要农艺性状,对其叶片中的光合色素含量进行测定,利用图位克隆技术对目的基因进行精细定位和测序鉴定,并对其编码蛋白进行分析与序列比对。【结果】突变体叶片中的光合色素含量比WT极显著降低,且细胞中存在活性氧(reactive oxygen species,ROS)的过量积累;突变体植株的生长发育受到严重影响,有效分蘖数、株高、剑叶长、剑叶宽、穗长、每穗粒数、结实率及单株产量等均显著下降,但粒厚显著增加;遗传分析表明,lmes7的突变表型受单隐性核基因控制;利用图位克隆技术将目的基因精细定位在水稻12号染色体上RM28486和RM28489之间的90 kb区域内;PCR测序分析表明,lmes7突变体中一个编码ATP-柠檬酸裂解酶的目标基因Os ACL-A2发生了7个碱基缺失,导致该基因发生移码突变,蛋白翻译提前终止;对水稻OsACL-A2蛋白的进化分析与序列比对可知,lmes7突变位点发生在琥珀酰辅酶A合成酶结构域,lmes7是OsACL-A2新的等位变异。展开更多
Among plant hormones,cytokinins have been extensively studied for over a century due to their central roles in regulating plant development,physiology,and environmental responses.In this study,we chemically synthesize...Among plant hormones,cytokinins have been extensively studied for over a century due to their central roles in regulating plant development,physiology,and environmental responses.In this study,we chemically synthesized several Cytokinin-Active ingreDients(CADs)and evaluated their effects on the in vitro regeneration of Sansevieria trifasciata and seedling growth of Nicotiana tabacum,comparing their activities with established cytokinins,kinetin and zeatin.Our results show that CADs promote cell division and shoot proliferation in S.trifasciata,with the highest shoot numbers per explant observed at CAD-A(0.9 mg L^(-1)),cycle-iP(0.1 mg L^(-1)),and zeatin(0.3 mg L^(-1)),all significantly different from kinetin(0.3 mg L^(-1))—the previously suggested cytokinin for in vitro shoot proliferation in this plant.CAD-A and CAD-B at 0.9 mg L^(-1)increased leaf number by approximately 4.5,significantly outperforming kinetin at 0.3 mg L^(-1).In tobacco seedlings,CAD-B at 0.3 mg L^(-1)significantly enhanced root number(7.3)comparable to kinetin(6.7)at the same concentration.Overall seedling height increased more than two-fold under both CAD-B and kinetin treatments compared to control plants.The bioactivity of CADs under in vitro conditions closely parallels that of kinetin,supporting their potential as effective cytokinin mimetics.Collectively,these results indicate that synthesized CADs can serve as potent alternatives to natural cytokinins for plant tissue culture and developmental studies,with promising applications in propagation and regeneration protocols.展开更多
目的评估脓毒症性凝血病(sepsis-induced coagulopathy,SIC)患者收住重症监护病房(intensive care unit,ICU)期间他汀类药物治疗能否降低其死亡风险。方法基于重症监护数据库-Ⅳ(Medical Information Mart for Intensive CareⅣ,MIMIC-...目的评估脓毒症性凝血病(sepsis-induced coagulopathy,SIC)患者收住重症监护病房(intensive care unit,ICU)期间他汀类药物治疗能否降低其死亡风险。方法基于重症监护数据库-Ⅳ(Medical Information Mart for Intensive CareⅣ,MIMIC-Ⅳ)构建回顾性队列,纳入2008—2022年期间收治于美国贝斯以色列女执事医疗中心ICU且符合SIC诊断的成年患者9095例,根据住ICU期间是否使用他汀类药物分为他汀类药物使用组(2894例,31.8%)和未使用他汀类药物组(6201例,68.2%)。主要结局为28d全因死亡率。采用多变量Cox比例风险模型计算调整后风险比(hazard ratio,HR),并采用倾向性评分匹配(propensity score matching,PSM)减少两组基线特征间的偏移,并使用多种基于倾向评分的加权方法——包括逆概率处理加权(inverse probability of treatment weighting,IPTW)、标准化死亡率比加权(standardized mortality ratio weighting,SMRW)、倾向性调整加权(propensity adjustment weighting,PAW)和重叠加权(overlap weighting,OW)验证结果的稳健性。利用E值评估未测量混杂因素对研究结果的潜在影响。结果共纳入9095例SIC患者,整体28d死亡率为25.54%。他汀类药物使用组28d死亡率为17.59%(509/2894),未使用他汀类药物组为29.25%(1814/6201)。多变量Cox回归显示,他汀类药物治疗与降低28d死亡率显著相关(调整后HR=0.72,95%CI:0.64~0.8,P<0.001)。1∶1倾向评分匹配后(匹配后样本共4582例)结果一致(HR=0.73,95%CI:0.64~0.83,P<0.001);IPTW、SMRW、PAW和OW等加权方法的HR范围为0.68~0.83,均有统计学意义(P<0.05)。Kaplan–Meier曲线显示他汀类药物使用组28d累计生存率高于未使用他汀类药物组(log-rank P<0.001)。在排除多种敏感性情景下,校正后HR仍均显著低于1;亚组分析总体亦显示一致的保护性(HR<1)。E值(点估计)=1.79。结论SIC成人患者收住ICU期间使用他汀类药物治疗可显著改善生存预后。展开更多
文摘【目的】研究水稻防御反应和叶片早衰相关基因的分子机理。【方法】从粳稻武运粳7号诱变库中筛选出一个类病变早衰突变体lmes7(lesion mimic and early senescence 7)。调查统计了该突变体的主要农艺性状,对其叶片中的光合色素含量进行测定,利用图位克隆技术对目的基因进行精细定位和测序鉴定,并对其编码蛋白进行分析与序列比对。【结果】突变体叶片中的光合色素含量比WT极显著降低,且细胞中存在活性氧(reactive oxygen species,ROS)的过量积累;突变体植株的生长发育受到严重影响,有效分蘖数、株高、剑叶长、剑叶宽、穗长、每穗粒数、结实率及单株产量等均显著下降,但粒厚显著增加;遗传分析表明,lmes7的突变表型受单隐性核基因控制;利用图位克隆技术将目的基因精细定位在水稻12号染色体上RM28486和RM28489之间的90 kb区域内;PCR测序分析表明,lmes7突变体中一个编码ATP-柠檬酸裂解酶的目标基因Os ACL-A2发生了7个碱基缺失,导致该基因发生移码突变,蛋白翻译提前终止;对水稻OsACL-A2蛋白的进化分析与序列比对可知,lmes7突变位点发生在琥珀酰辅酶A合成酶结构域,lmes7是OsACL-A2新的等位变异。
文摘Among plant hormones,cytokinins have been extensively studied for over a century due to their central roles in regulating plant development,physiology,and environmental responses.In this study,we chemically synthesized several Cytokinin-Active ingreDients(CADs)and evaluated their effects on the in vitro regeneration of Sansevieria trifasciata and seedling growth of Nicotiana tabacum,comparing their activities with established cytokinins,kinetin and zeatin.Our results show that CADs promote cell division and shoot proliferation in S.trifasciata,with the highest shoot numbers per explant observed at CAD-A(0.9 mg L^(-1)),cycle-iP(0.1 mg L^(-1)),and zeatin(0.3 mg L^(-1)),all significantly different from kinetin(0.3 mg L^(-1))—the previously suggested cytokinin for in vitro shoot proliferation in this plant.CAD-A and CAD-B at 0.9 mg L^(-1)increased leaf number by approximately 4.5,significantly outperforming kinetin at 0.3 mg L^(-1).In tobacco seedlings,CAD-B at 0.3 mg L^(-1)significantly enhanced root number(7.3)comparable to kinetin(6.7)at the same concentration.Overall seedling height increased more than two-fold under both CAD-B and kinetin treatments compared to control plants.The bioactivity of CADs under in vitro conditions closely parallels that of kinetin,supporting their potential as effective cytokinin mimetics.Collectively,these results indicate that synthesized CADs can serve as potent alternatives to natural cytokinins for plant tissue culture and developmental studies,with promising applications in propagation and regeneration protocols.
文摘目的评估脓毒症性凝血病(sepsis-induced coagulopathy,SIC)患者收住重症监护病房(intensive care unit,ICU)期间他汀类药物治疗能否降低其死亡风险。方法基于重症监护数据库-Ⅳ(Medical Information Mart for Intensive CareⅣ,MIMIC-Ⅳ)构建回顾性队列,纳入2008—2022年期间收治于美国贝斯以色列女执事医疗中心ICU且符合SIC诊断的成年患者9095例,根据住ICU期间是否使用他汀类药物分为他汀类药物使用组(2894例,31.8%)和未使用他汀类药物组(6201例,68.2%)。主要结局为28d全因死亡率。采用多变量Cox比例风险模型计算调整后风险比(hazard ratio,HR),并采用倾向性评分匹配(propensity score matching,PSM)减少两组基线特征间的偏移,并使用多种基于倾向评分的加权方法——包括逆概率处理加权(inverse probability of treatment weighting,IPTW)、标准化死亡率比加权(standardized mortality ratio weighting,SMRW)、倾向性调整加权(propensity adjustment weighting,PAW)和重叠加权(overlap weighting,OW)验证结果的稳健性。利用E值评估未测量混杂因素对研究结果的潜在影响。结果共纳入9095例SIC患者,整体28d死亡率为25.54%。他汀类药物使用组28d死亡率为17.59%(509/2894),未使用他汀类药物组为29.25%(1814/6201)。多变量Cox回归显示,他汀类药物治疗与降低28d死亡率显著相关(调整后HR=0.72,95%CI:0.64~0.8,P<0.001)。1∶1倾向评分匹配后(匹配后样本共4582例)结果一致(HR=0.73,95%CI:0.64~0.83,P<0.001);IPTW、SMRW、PAW和OW等加权方法的HR范围为0.68~0.83,均有统计学意义(P<0.05)。Kaplan–Meier曲线显示他汀类药物使用组28d累计生存率高于未使用他汀类药物组(log-rank P<0.001)。在排除多种敏感性情景下,校正后HR仍均显著低于1;亚组分析总体亦显示一致的保护性(HR<1)。E值(点估计)=1.79。结论SIC成人患者收住ICU期间使用他汀类药物治疗可显著改善生存预后。
