搭建由交流动态送丝过渡(active super motion transfer,ASMT)焊接系统、高速摄像、同步波形信息采集系统、红外热像仪组成的试验系统,研究了不同EP/EN周期下2A12铝合金交流ASMT焊接熔滴过渡、温度场及焊缝成形的影响规律。结果表明,不...搭建由交流动态送丝过渡(active super motion transfer,ASMT)焊接系统、高速摄像、同步波形信息采集系统、红外热像仪组成的试验系统,研究了不同EP/EN周期下2A12铝合金交流ASMT焊接熔滴过渡、温度场及焊缝成形的影响规律。结果表明,不同EP/EN周期下,焊接过程稳定无飞溅,EP阶段电弧半包熔滴,呈“钟罩”型;EN阶段电弧斑点沿焊丝“上爬”,加速焊丝熔化,大熔滴过渡造成熔池震荡,对熔池有搅拌作用。此外,直流EN焊缝温度相比EP焊缝温度降低约50%,实现了焊接电流和焊缝温度的解耦。交流ASMT EP/EN=3∶3时获得外观成形良好的焊缝,焊缝余高为3.15 mm、熔宽为5.04 mm,介于直流EP和直流EN之间。展开更多
为了研究乳腺过表达褪黑素合成限速酶乙酰血清素甲基转移酶(ASMT,HIOMT)基因奶山羊的生物安全性,试验针对乳腺过表达褪黑素合成酶ASMT基因奶山羊模型,记录了转基因山羊的生长发育数据、检测了血液及尿液中生理生化指标,并对肠道微生物...为了研究乳腺过表达褪黑素合成限速酶乙酰血清素甲基转移酶(ASMT,HIOMT)基因奶山羊的生物安全性,试验针对乳腺过表达褪黑素合成酶ASMT基因奶山羊模型,记录了转基因山羊的生长发育数据、检测了血液及尿液中生理生化指标,并对肠道微生物、乳成分及褪黑素含量进行分析。结果表明:1)转基因阳性羊0,3,6,12月龄体重、体长、身高和胸围四项生长指标和对照羊均无显著差异(P>0.05);2)转基因阳性羊体温、胆固醇、血糖、总蛋白和各类型细胞含量及尿液中蛋白质、葡萄糖含量等指标与对照羊无显著差异(P>0.05);3)16S r DNA菌群测序结果表明,转基因阳性羊与对照羊肠道微生物群落组成及优势菌群均无显著差异(P>0.05);4)转基因阳性羊褪黑素含量显著高于对照羊(P<0.05),且乳中褪黑素含量显著高于血液(P<0.05),转基因阳性羊乳中乳蛋白和干物质含量显著高于对照羊(P<0.05),转基因阳性羊体细胞数显著低于对照羊(P<0.05)。说明乳腺过表达褪黑素合成限速酶ASMT基因不影响转基因奶山羊健康,而且会提高奶山羊乳品质。展开更多
Salt stress,especially the increasing secondary salt stress,severely compromises apple production worldwide.Mitigation of oxidative damage caused by salt stress is critical for salt tolerance in apple plants.However,i...Salt stress,especially the increasing secondary salt stress,severely compromises apple production worldwide.Mitigation of oxidative damage caused by salt stress is critical for salt tolerance in apple plants.However,it remains unclear how the salt signal triggers the excessive reactive oxygen species(ROS)mitigation system in apple.In this study,we identified a salt-induced gene Md GRF10(encoding a 14-3-3 protein),whose overexpression conferred transgenic apple plants reduced oxidative damage and enhanced salt tolerance.Furthermore,a salt-activated receptor-like cytoplasmic kinase MdPBL34 was found to interact with and phosphorylate the C-terminal of MdGRF10.This phosphorylation promoted the interaction between MdGRF10 and a melatonin rate-limiting synthetase MdASMT1(N-acetylserotonin methyltransferase).Its overexpression or knockdown by CRISPR/Cas9in transgenic apple plants demonstrated that MdASMT1 is critical in melatonin-mediated ROS scavenging for salt tolerance.Their interaction stabilizes MdASMT1 by decreasing its ubiquitinmediated degradation for increased melatonin level,decreased oxidative damage and therefore promoted salt tolerance.Our findings revealed that 14-3-3 protein could integrate the salt signal in a phosphorylation-dependent manner.Moreover,MdPBL34 was also identified for the first time to be involved in salt signaling.Our research uncovered a novel MdPBL34-Md GRF10-MdASMT1 regulatory module in response to salt stress in apple,which will contribute to the molecular breeding of melatoninenriched salt-tolerant apple trees.展开更多
文摘为了研究乳腺过表达褪黑素合成限速酶乙酰血清素甲基转移酶(ASMT,HIOMT)基因奶山羊的生物安全性,试验针对乳腺过表达褪黑素合成酶ASMT基因奶山羊模型,记录了转基因山羊的生长发育数据、检测了血液及尿液中生理生化指标,并对肠道微生物、乳成分及褪黑素含量进行分析。结果表明:1)转基因阳性羊0,3,6,12月龄体重、体长、身高和胸围四项生长指标和对照羊均无显著差异(P>0.05);2)转基因阳性羊体温、胆固醇、血糖、总蛋白和各类型细胞含量及尿液中蛋白质、葡萄糖含量等指标与对照羊无显著差异(P>0.05);3)16S r DNA菌群测序结果表明,转基因阳性羊与对照羊肠道微生物群落组成及优势菌群均无显著差异(P>0.05);4)转基因阳性羊褪黑素含量显著高于对照羊(P<0.05),且乳中褪黑素含量显著高于血液(P<0.05),转基因阳性羊乳中乳蛋白和干物质含量显著高于对照羊(P<0.05),转基因阳性羊体细胞数显著低于对照羊(P<0.05)。说明乳腺过表达褪黑素合成限速酶ASMT基因不影响转基因奶山羊健康,而且会提高奶山羊乳品质。
基金supported by the National Key Research&Development Program of China(2022YFF1003100,2023YFD2301000)the National Natural Science Fund(32172540)+3 种基金the Hainan Province Science and Technology Special Fund(ZDYF2021XDNY161)Sanya Yazhou Bay Science and Technology City(SYND-2021-08)the 2115 Talent Development Program of China Agricultural Universitythe 111 Project(B17043)。
文摘Salt stress,especially the increasing secondary salt stress,severely compromises apple production worldwide.Mitigation of oxidative damage caused by salt stress is critical for salt tolerance in apple plants.However,it remains unclear how the salt signal triggers the excessive reactive oxygen species(ROS)mitigation system in apple.In this study,we identified a salt-induced gene Md GRF10(encoding a 14-3-3 protein),whose overexpression conferred transgenic apple plants reduced oxidative damage and enhanced salt tolerance.Furthermore,a salt-activated receptor-like cytoplasmic kinase MdPBL34 was found to interact with and phosphorylate the C-terminal of MdGRF10.This phosphorylation promoted the interaction between MdGRF10 and a melatonin rate-limiting synthetase MdASMT1(N-acetylserotonin methyltransferase).Its overexpression or knockdown by CRISPR/Cas9in transgenic apple plants demonstrated that MdASMT1 is critical in melatonin-mediated ROS scavenging for salt tolerance.Their interaction stabilizes MdASMT1 by decreasing its ubiquitinmediated degradation for increased melatonin level,decreased oxidative damage and therefore promoted salt tolerance.Our findings revealed that 14-3-3 protein could integrate the salt signal in a phosphorylation-dependent manner.Moreover,MdPBL34 was also identified for the first time to be involved in salt signaling.Our research uncovered a novel MdPBL34-Md GRF10-MdASMT1 regulatory module in response to salt stress in apple,which will contribute to the molecular breeding of melatoninenriched salt-tolerant apple trees.
