Specific Protein Properties of Setcreasea pupurea Boom under Copper Stress

[Objective] This study was to investigate the expression of the specific protein in Setcreasea purpurea Boom under copper stress, with the aim to clarify the copper tolerance mechanism of S. purpurea. [Method] Methods of water culture, elec- trophoresis and chromatography were used to analyze the molecular weight of the specific protein in the copper hyperaccumulator S. purpurea, as well as its expression time and the minimum copper concentration for the expression. And the specific protein was isolated and purified. [Result] Under copper stress, the minimum concentra- tion of copper to induce the expression of the specific protein from S. purpurea was 50 umol/L, and the expression time of the protein was in the 4th week with the molecular weight of 89.4 kDa. [Conclusion] The results show that the copper tolerance of S. purpurea is closely related with the expression of the specific protein.

Exogenous Nitric Oxide Involved in Subcellular Distribution and Chemical Forms of Cu^(2+) Under Copper Stress in Tomato Seedlings

Nitric oxide（NO）,a bioactive signaling molecule,serves as an antioxidant and anti-stress agent under abiotic stress.A hydroponics experiment was conducted to investigate the effects of sodium nitroprusside（SNP）,a NO donor,on tomato seedlings exposed to 50 μmol L-1CuCl 2.The results show that copper is primarily stored in the soluble cell sap fraction in the roots,especially after treatment with Cu＋SNP treatment,which accounted for 66.2% of the total copper content.The copper concentration gradually decreased from the roots to the leaves.In the leaves,exogenous NO induces the storage of excess copper in the cell walls.Copper stress decreases the proportion of copper integrated with pectates and proteins,but exogenous NO remarkably reverses this trend.The alleviating effect of NO is blocked by hemoglobin.Thus,exogenous NO is likely involved in the regulation of the subcellular copper concentrations and its chemical forms under copper stress.Although exogenous NO inhibited the absorption and transport of excess copper to some extent,the copper accumulation in tomato seedlings significantly increased under copper stress.The use of exogenous NO to enhance copper tolerance in some plants is a promising method for copper remediation.

Cu Stress-Induced Transcriptome Alterations in Sorghum and Expression Analysis of the Transcription Factor-Encoding Gene SbWRKY24

Sorghum is not only an important bio-energy crop but also a vital raw material for brewing.Exogenous copper affects the growth and metabolism of crops in specific ways.This study identified 8475 differentially expressed genes(DEGs)by high-throughput transcriptome sequencing in the sorghum cultivar‘Jinnuoliang 2’after 24 h of treatment with 10 mM CuSO4.Using GO analysis,476 genes were functionally annotated,which were mainly related to catabolism and biosynthetic processes.Additionally,90 pathways were annotated by employing the KEGG analysis.Among them,glutathione metabolism and peroxisome were induced,while photosynthesis,photosynthesis-antenna protein,and carbon sequestration of photosynthetic organisms were inhibited.Of the DEGs,399 were identified to encode transcription factors belonging to 49 families.This study also identified a WRKY transcription factor-encoding gene SbWRKY24 from the transcriptome data.For studying its function,the relative expression levels of SbWRKY24 in roots and leaves post-treatment with different growth hormones and exposure to a variety of abiotic stresses were detected by RT-qPCR.SbWRKY24 showed treatment-and tis-sue-specific expression patterns,indicating its unique role in stress tolerance.This study lays a theoretical basis for the functional exploration of SbWRKY24,elucidating the mechanism of copper resistance,and elaborating on the stress responses in sorghum.It also guides the exploration of the molecular mechanism of copper ions inducing intracellular signal transduction pathways.

Hydrogen Sulfide Promotes Wheat Seed Germination and Alleviates Oxidative Damage against Copper Stress

With the enhancement of copper （Cu） stress, the germination percentage of wheat seeds decreased gradually. Pretreatment with sodium hydrosulfide （NariS）, hydrogen sulfide （H2S） donor alleviated the inhibitory effect of Cu stress in a dose- dependent manner; whereas little visible symptom was observed in germinating seeds and radicle tips cultured in NariS solutions. It was verified that H2S or HS- rather than other sulfur-containing components derived from NariS attribute to the potential role in promoting seed germination against Cu stress. Further studies showed that NariS could promote amylase and esterase activities, reduce Cu-induced disturbance of plasma membrane integrity in the radicle tips, and sustain lower levels of malondialdehyde and H202 in germinating seeds. Furthermore, NariS pretreatment increased activities of superoxide dismutase and catalase and decreased that of lipoxygenase, but showed no significant effect on ascorbate peroxidase. Alternatively, NariS prevented uptake of Cu and promoted the accumulation of free amino acids in seeds exposed to Cu. In addition, a rapid accumulation of endogenous H2S in seeds was observed at the early stage of germination, and higher level of H2S in NaHS-pretreated seeds. These data indicated that H2S was involved in the mechanism of germinating seeds＇ responses to Cu stress.

Copper Ions Stimulate the Proliferation of Hepatic Stellate Cells via Oxygen Stress in vitro

This study examined the effect of copper ions on the proliferation of hepatic stellate cells （HSCs） and the role of oxidative stress in this process in order to gain insight into the mechanism of he- patic fibrosis in Wilson＇s disease. LX-2 cells, a cell line of human HSCs, were cultured in vitro and treated with different agents including copper sulfate, N-acetyl cysteine （NAC） and buthionine sulfoxi- mine （BSO） for different time. The proliferation of LX-2 cells was measured by non-radioactive cell proliferation assay. Real-time PCR and Westem blotting were used to detect the mRNA and protein ex- pression of platelet-derived growth factor receptor 13 subunit （PDGFI3R）, ELISA to determine the level of glutathione （GSH） and oxidized glutathione （GSSG）, dichlorofluorescein assay to measure the level of reactive oxygen species （ROS）, and lipid hydroperoxide assay to quantify the level of lipid peroxide （LPO）. The results showed that copper sulfate over a certain concentration range could promote the pro- liferation of LX-2 cells in a time- and dose-dependent manner. The effect was most manifest when LX-2 cells were treated with copper sulfate at a concentration of 100 ~tmol/L for 24 h. Additionally, copper sulfate could dose-dependently increase the levels of ROS and LPO, and decrease the ratio of GSH/GSSG in LX-2 cells. The copper-induced increase in mRNA and protein expression of PDGF^R was significantly inhibited in LX-2 cells pre-treated with NAC, a precursor of GSH, and this phenome- non could be reversed by the intervention of BSO, an inhibitor of NAC. It was concluded that copper ions may directly stimulate the proliferation of HSCs via oxidative stress. Anti-oxidative stress therapies may help suppress the copper-induced activation and proliferation of HSCs.

樟树对铜胁迫的生长和生理响应及铜富集转运特性分析

以前期在铜污染矿区修复中筛选出的耐铜樟树(Cinnamomum camphora(L.)Presl)为材料,通过盆栽模拟实验,以不添加铜为对照(CK),设置50、150、300、600、900、1200 mg/kg 6个处理浓度,胁迫处理60 d后,测定樟树的生物量积累、叶绿素含量、生理生化指标及樟树对铜离子的富集和转移量,分析不同浓度铜处理对耐铜樟树生长、生理生化的影响,以及铜在不同组织的富集转运规律。结果显示,樟树对铜胁迫表现出低浓度(150 mg/kg)促进生长,高浓度抑制生长的趋势。超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化物酶(Peroxidase,POD)、过氧化氢酶(Catalase,CAT)、过氧化氢(Hydrogen peroxide,H_(2)O_(2))、游离脯氨酸和可溶性糖含量等生理指标在900 mg/kg处理时没有显著升高;谷胱甘肽还原酶(Glutathione reductase,GR)随着处理浓度的升高逐渐降低;丙二醛(Malondialdehyde,MDA)、谷胱甘肽(Glutathione,GSH)含量则随着处理浓度的升高逐渐升高。各器官铜含量的大小顺序为根>叶>茎,樟树主要将铜富集在根系,往地上茎和叶的转移率很低,极大地降低了对茎、叶的铜毒害作用,且随着处理浓度的增加,铜由根系向叶片的转移率IF(Leaf/Root)由对照处理的0.078逐降至1200 mg/kg处理时的0.007;铜由根系向茎的转移率IF(Stem/Root)由对照处理的0.06逐降至1200 mg/kg处理时的0.005。综合其生长、生理及铜的富集转运特性,樟树对铜具有较好的耐受性,耐受浓度可达900 mg/kg,是可用于铜污染土壤种植的理想材料。

肝豆补肾汤通过抑制铁死亡和内质网应激改善肝豆状核变性模型TX小鼠卵巢组织损伤

目的观察肝豆补肾汤对肝豆状核变性(hepatolenticular degeneration,HLD)小鼠卵巢损伤的保护作用,并探究其分子机制。方法以TX小鼠作为HLD模型,将其分为HLD组、青霉胺组和肝豆补肾汤组,另设DL同系小鼠作为正常对照组。测量小鼠体质量、卵巢质量、卵巢系数。采用促性腺激素促排卵法观察小鼠的排卵情况。采用苏木精—伊红(hematoxylin-eosin,HE)染色法观察小鼠卵巢的组织形态,透射电子显微镜下观察卵巢组织的超微结构。采用比色法测定血清铁含量,TBA法检测卵巢组织中丙二醛(malondialdehyde,MDA)含量,微量酶标法检测卵巢组织中还原型谷胱甘肽(glutathione,GSH)及氧化型谷胱甘肽(oxidized glutathione,GSSG)水平。采用Western blot法检测小鼠卵巢组织铁死亡相关标志物前列腺素内过氧化物合酶2(prostaglandin-endoperoxide synthase 2,PTGS2)和谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)水平,及内质网应激通路相关蛋白[葡萄糖调节蛋白78(glucose-regulated protein 78,GRP78)、蛋白激酶核糖核酸样内质网激酶(protein kinase RNA-like endoplasmic reticulum kinase,PERK)、磷酸化PERK(phosphorylated PERK,p-PERK)、真核起始因子2α(eukaryotic initiation factor 2 alpha-subunit,eIF2α)、磷酸化eIF2α(phosphorylated eIF2α,p-eIF2α)、活化转录因子4(activating transcription factor 4,ATF4)和C/EBP同源蛋白(C/EBP homologous protein,CHOP)]的表达水平。结果HE染色显示HLD组小鼠卵细胞形态结构受损严重,闭锁卵泡显著增加;透射电子显微镜下HLD组小鼠线粒体皱缩明显,出现内质网肿胀和脱颗粒等内质网应激表现。与正常对照组比较,HLD组小鼠卵巢质量、排卵数均显著降低(P<0.05),血清铁及卵巢组织中MDA、GSSG水平显著升高(P<0.05),卵巢组织中GSH水平、GSH/GSSG显著降低(P<0.05),卵巢组织中PTGS2、GRP78、p-PERK、p-eIF2α、ATF4、CHOP表达水平均显著升高(P<0.05),GPX4表达水平显著降低(P<0.05)。与HLD组比较,肝豆补肾汤组小鼠的卵泡形态、线粒体和内质网结构均显著改善,促排卵后排卵数显著升高(P<0.05),血清铁及卵巢组织中MDA和GSSG水平显著降低(P<0.05),卵巢组织中GSH水平和GSH/GSSG显著升高(P<0.05),卵巢组织中PTGS2、GRP78、p-PERK、p-eIF2α、CHOP表达水平显著降低(P<0.05),卵巢组织中GPX4表达水平显著升高(P<0.05)。结论肝豆补肾汤可减轻TX小鼠铜沉积诱导的卵巢损伤,其机制可能与抑制铁死亡和PERK通路介导的内质网应激有关。

基于转录组的海州香薷COPT铜转运蛋白家族鉴定及响应铜胁迫表达分析

为了解海州香薷(Elsholtzia splendens)COPT(copper transporter)铜转运蛋白对铜胁迫的响应规律,运用生物信息学方法对海州香薷转录组数据库中的COPT家族成员进行鉴定与分析,构建植物表达载体探究蛋白的亚细胞定位.结果显示:海州香薷转录组中有11个EsCOPT成员,它们编码的蛋白质由72~159个氨基酸组成,等电点介于4.72~9.92,平均相对分子质量为12.870×10^(3).11个成员均为膜蛋白,系统进化树分析显示EsCOPT蛋白分别属于3个亚组.正常条件下,EsCOPT2和EsCOPT9表达量较高,铜处理后,除EsCOPT5的表达无明显变化外,其他EsCOPTs的表达均呈下降趋势.全长EsCOPT9编码的蛋白具有3个跨膜结构域且N末端较短,共定位实验表明EsCOPT9-GFP定位于液泡膜上.

埃洛石纳米管对铜胁迫下小麦幼苗生长的影响

在水培条件下设置3个铜(Cu)处理[20 mg/L Cu^(2+)(20Cu)、50 mg/L Cu^(2+)(50Cu)和100 mg/L Cu^(2+)(100Cu)],研究外源添加50 mg/L埃洛石纳米管(HNTs)对Cu胁迫下小麦幼苗生长、气孔大小、叶绿体色素含量、根系氧化损伤、植株内Cu^(2+)含量的影响,以期为HNTs缓解重金属污染对作物生长的影响提供理论依据。结果表明,外源添加HNTs显著提高了Cu胁迫下小麦幼苗的株高、根长,20Cu+HNTs、50Cu+HNTs、100Cu+HNTs处理株高分别提高了13.10%、26.45%、28.30%,根长分别提高了62.87%、56.68%、92.34%;外源添加HNTs显著提高了Cu胁迫下小麦幼苗干、鲜质量,叶绿素、类胡萝卜素含量,根系活力,降低了根系氧化损伤程度,其中,叶绿素a含量分别提高了34.34%、18.09%、54.76%,叶绿素b含量分别提高了44.83%、25.93%、43.75%,根系活力分别提高了38.16%、339.48%、453.56%;与100Cu处理相比,100Cu+HNTs处理小麦幼苗根系、叶片中Cu^(2+)含量分别降低了19.18%、37.02%。综上,外源添加HNTs能够降低小麦幼苗中Cu^(2+)含量,缓解重金属Cu对小麦幼苗的毒性,促进其生长。

红树植物功能性状对盐和铜胁迫的响应

目前,室内通过人工控制方式开展红树林对环境胁迫的响应研究,忽视了不同红树植物物种的生长习性,且以单一胁迫为主。通过野外生长与人工控制相结合方式,研究5个时期(2018.6—2020.8)盐和铜胁迫对3种红树植物(秋茄、拉关木和木榄)11种功能性状的影响,使用单因素和双因素方差分析研究不同时期不同树种下盐和铜胁迫对叶片功能性状的影响,回答红树植物功能性状对盐和铜单一及复合胁迫响应的科学问题。结果表明,不同时期下,三种红树植物功能性状具有明显差异。随着时间增长,三种植物的碳含量和冠层高度均呈升高趋势,其他功能性状因物种不同而表现出不同趋势;与乡土红树植物(秋茄和木榄)相比,外来入侵物种(拉关木)具有更快的生长速度。不同时期下,拉关木比秋茄和木榄具有更好耐盐性,三个物种的植物生长发育对铜胁迫的响应均不敏感。大部分时期下,单一盐胁迫对拉关木的植物功能性状无显著影响(P<0.05),对秋茄和木榄的碳含量、冠层高度和比叶面积有显著影响(P<0.05);单一铜胁迫对三个物种的绝大多数功能性状无显著影响。另外,盐-铜复合胁迫对秋茄叶片碳、磷、氮磷比及冠层高度有显著影响(P<0.05),对拉关木叶片碳、铜含量、冠层高度、比叶面积有显著影响(P<0.05),仅对木榄SPAD值有显著影响(P<0.05)。在红树林保护修复工作中,研究成果可为红树林退化原因和机理阐释、红树林生长监测评估、生境治理以及树种选择提供一定的理论依据。

Grafting Enhances Copper Tolerance of Cucumber Through Regulating Nutrient Uptake and Antioxidative System

An experiment was carried out to determine plant growth, mineral uptake, lipid peroxidation, antioxidative enzymes, and antioxidant of cucumber plants （Cucumis sativus L. cv. Xintaimici） under copper stress, either ungrafted or grafted onto the rootstock （Cucurbitaficifolia）. Excess Cu inhibited growth, photosynthesis, and pigment synthesis of grafted and ungrafted cucumber seedlings and significantly increased accumulation of Cu in roots besides reducing mineral uptake. Cu concentration in roots of grafted cucumber plants was significantly higher than that of ungrafted plants and obviously lower in leaves. The accumulation of reactive oxygen species （ROS） significantly increased in cucumber leaves under Cu stress and resulted in lipid peroxidation, and the levels of ROS and lipid peroxidation were greatly decreased by grafting. Activities of protective enzymes （superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX; dehydroascorbate reductase, DHAR; glutathione reductase, GR） and the contents of ascorbate and glutathione in leaves of grafted plants were significantly higher than those of ungrafted plants under Cu stress. Better performance of grafted cucumber plants were attributed to the higher ability of Cu accumulation in their roots, better nutrient status, and the effective scavenging system of ROS.

Grafting Raises the Cu Tolerance of Cucumber Through Protecting Roots Against Oxidative Stress Induced by Cu Stress

A greenhouse experiment was carried out to determine plant growth, reactive oxygen species （ROS） metabolism in roots and functions of plasma membrane （PM） and tonoplast in cucumber seedlings （Cucumis sativus L. ev. Xintaimici） treated with 40 μmol L^-1 CuSO4·5H2O, which were either ungrafted or grafted onto the rootstock （Cucurbitaficifolia）. Cu treatment inhibited growth, induced significant accumulation of H2O2 and led to serious lipid peroxidation in cucumber roots, and the ROS-scavenging enzymes activities in grafted seedlings roots were significantly higher than that of ungrafted plants, thus less accumulation in grafted cucumber roots induced by Cu. As a result, lipid peroxidation in roots decreased. Furthermore, the activities of H^-ATPase, H＋-PPase and Ca^2＋-ATPase in PM and/or tonoplast in grafted cucumber seedlings under Cu stress were obviously higher than that in ungrafted plants, resulting into higher ability in grafted plants to expulse the excess H＋, promote the cytoplasm alkalinization, regulate the intracellular Ca^2＋ concentration and brought the cytoplasma concentration of free Ca2＋ to extremely low level under Cu stress.

Grafting Increases the Copper Tolerance of Cucumber Seedlings by Improvement of Polyamine Contents and Enhancement of Antioxidant Enzymes Activity

The aim of the study is to determine whether grafting could improve antioxidant enzyme activities and polyamine contents in leaves of cucumber plants（Cucumis sativus L.cv.Xintaimici） under copper stress.Grafted（using Cucurbita ficifolia as rootstock） and ungrafted cucumber seedlings were cultured in deep flow technique（DFT） with the Cu2＋ concentration of 40 μmol L-1.The results showed that on the 9th day of copper stress treatment,the contents of malondialdehyde（MDA） and hydrogen peroxide（H2O2）,superoxide radical（） producing rate,and electrolyte leakage percentage were significantly lower in grafted seedlings in comparison to those of the ungrafted seedlings,whereas the activities of antioxidants such as superoxide dismutase（SOD,EC 1.15.1.1）,peroxidase（POD,EC 1.11.1.7）,ascorbate peroxidase（APX,EC 1.11.1.11）,catalase（CAT,EC 1.11.1.6）,glutathione reductase（GR,EC 1.6.4.2）,and monodehydroascorbate reductase（MDHAR,EC 1.6.5.4） of grafted seedlings were also significantly higher than that of ungrafted seedlings,and the contents of free proline and soluble protein of grafted seedlings were significantly higher than that of ungrafted seedlings.Cu2＋ treatment increased the putrescine（Put） level and lowered the spermidine（Spd） and spermine（Spm） levels,thereby reducing the Put/（Spd ＋ Spm） ratio in leaves of grafted and ungrafted seedlings.Grafting markedly reversed these Cu-induced effects for all three PAs and partially restored the Put/（Spd ＋ Spm） ratio in leaves.These results suggest that grafting can enhance the tolerance of cucumber seedlings to Cu2＋ stress by increasing the activities of antioxidants and the levels of endogenous Spd and Spm,decreasing the Put/（Spd ＋ Spm） ratio and the levels of ROS,promoting free proline and soluble protein synthesis in cucumber seedling leaves.

延性铜合金颈缩后力学响应工程修正方法

液体火箭发动机中大量采用延性铜合金,严苛载荷导致其普遍工作于大塑性变形状态。由于无法有效处理拉伸试验颈缩后数据,传统工程强度分析所用材料本构无法充分反映出材料的真实承载能力。针对某延性铜合金开展常温单轴拉伸试验,并从工程强度分析的角度提出通用修正函数与参数拟合原则,随后通过有限元颈缩仿真拟合得到加权因子w=0.75和指数修正因子n=2.4。研究表明,有限元颈缩仿真的载荷-位移响应对模型参数和网格具有收敛性,指数修正方法可更好地描述铜合金试件颈缩后响应,选取n=2.4可得到偏保守的材料性能估计。

人参对铜吸收规律及铜对基质养分影响

铜污染是严重影响药用植物生长发育的环境问题之一,为了明确人参对铜元素吸收规律和铜污染基质养分有效性影响,以两年生和三年生人参为试验材料,设置0、100、300、500和1000 mg/kg共5个铜离子浓度。结果表明,随着铜处理浓度增加,两年生人参和三年生人参根系活力均出现下降趋势,最多均在1000 mg/kg铜处理时分别显著下降62.33%和44.18%。两年生和三年生人参各时期铜含量均随着处理浓度的增加显著增加且均在绿果期达到基本稳定,红果期略有上升,在1000 mg/kg铜处理时两年生人参根、茎、叶分别显著上升214.03%、93.83%、216.03%,三年生人参根、茎、叶分别显著上升505.65%、337.84%、189.11%。铜处理后基质有效磷、碱解氮、速效钾含量和pH均显著下降,最多分别显著下降57.24%、34.78%、32.61%和22.06%。铜处理会显著改变人参对铁、锰和锌的吸收,在绿果期时,随着处理浓度的增加,两年生人参根部锌、铁和锰在1000 mg/kg铜处理时分别显著下降29.43%、20.71%和56.75%,叶片分别显著下降34.32%、31.62%和47.26%,三年生人参根部锌、铁和锰在1000 mg/kg铜处理时分别显著下降28.54%、19.91%和46.64%,叶片分别显著下降30.25%、16.56%和43.23%,两年生人参微量元素变化略高于三年生人参。总体上来看,三年生人参整体各部位铜含量高于两年生人参,人参各部位铜含量随处理浓度增加而上升。两年生和三年生人参在展叶期到绿果期过程铜吸收速率最快,在绿果期基本达到稳定。绿果期到红果期有略微上升但不明显。铜处理会降低基质养分有效性,也会阻碍人参对锌、铁和锰的吸收。

铜胁迫对人参生理参数和品质的影响研究

为探讨铜胁迫对人参(Panax ginseng C.A.Mey)生理参数及品质的影响机制,以三年生人参种苗为材料,水培处理21 d后研究铜对人参幼苗生长、各部位及对应细胞壁铜含量、生理特性及总皂苷含量的影响。结果表明,高浓度铜胁迫抑制人参生长,破坏细胞正常结构,干重鲜重较对照显著下降。随着铜处理浓度增大,人参各部位铜离子含量显著上升,根、茎、叶最高铜离子含量达48.30、68.58、130.77 mg·kg^(-1),铜离子主要分布在细胞壁内,根、茎、叶细胞壁所含铜量占总铜量均在150μmol·L^(-1)CuSO_(4)处理时最高,分别为57.74%、43.33%和37.24%。木质素含量随铜胁迫浓度增加而上升,相关合成酶活性也显著增强,在500μmol·L^(-1)CuSO_(4)处理时达到最大值。人参根和叶H2O2及丙二醛(MDA)含量随铜处理浓度增大而上升;过氧化物酶(POD)和过氧化氢酶(CAT)活性在300μmol·L^(-1)CuSO_(4)处理时达到最大值,根和叶片超氧化物歧化酶(SOD)活性在150μmol·L^(-1)CuSO_(4)处理时达到最大值,茎则在300μmol·L^(-1)CuSO_(4)处理时达到最大值。总皂苷含量在150μmol·L^(-1)CuSO_(4)处理达到最高。综上所述,人参在受到铜胁迫后可以通过增强抗氧化系统和增加木质素含量来抵抗铜胁迫。本研究结果为增强人参抗性及研究解除铜毒害作用的措施提供了依据。

铜过载介导心肌缺血再灌注损伤的作用及机制研究进展

急性心肌梗死(acute myocardial infarction,AMI)的发病率逐年上升,尽管临床上治疗方法不断增加,但大量患者冠脉再通后会出现心肌缺血再灌注损伤(myocardial ischemia-reperfusion injury,MIRI),使心肌损伤进一步加重,进而发生心肌机械性破坏、心力衰竭及恶性心律失常等心血管不良事件,导致患者生活质量下降及经济负担增加。铜作为人体中一种重要微量元素,其稳态与MIRI的发生、发展密切相关。当铜稳态失衡时,细胞内过量的铜通过氧化应激、炎症反应及铜死亡等一系列途径,加重MIRI。本文综述机体铜水平与MIRI的关系,深入探讨铜过载加重MIRI机制,有助于更全面了解铜过载在MIRI发生、发展中的作用,以期为MIRI提供新的治疗靶点。

铜锌复合胁迫下禾本科观赏草的富集、转运效应评价

研究禾本科观赏草在土壤重金属铜、锌复合污染下的富集、转运效应,筛选出耐性品种,为挖掘超富集植物及推动利用植物修复铜、锌污染环境提供参考依据。以9种常见禾本科观赏草作为试验植材,设置5个胁迫梯度,采用盆栽控制法,探究供试观赏草体内铜、锌含量分布状况并分析其对铜、锌的富集能力与转运特征。结果表明,不同供试观赏草吸收重金属铜、锌的能力存在差异;不同部位吸收重金属铜、锌的能力亦差异显著,供试观赏草地上部吸收锌的能力强于地下部,而地下部吸收铜的能力强于地上部。供试观赏草富集、转移锌的能力均强于铜,在锌富集系数、转运系数方面高于铜。采用隶属函数法及Q型聚类分析法,当相对距离为7.5时,可将供试观赏草划分为高、中、低铜锌积累型3类,丽色画眉草、细叶芒综合表现最强且属于高铜锌积累型。

养殖水域Cu^(2+)胁迫对虹鳟MT2基因表达模式的影响

为了探究水体中铜离子胁迫对虹鳟(Oncorhynchus mykiss)MT2基因表达模式的影响,开发Metallothioneins作为检测水域生态中重金属铜污染的分子标志,该研究利用TA克隆法获得了虹鳟MT2基因的CDS序列,检测了MT2基因在虹鳟不同组织中的表达模式,以及Cu^(2+)胁迫(Cu^(2+)浓度75、150和300μg/L)后1、2、3和4 d和胁迫恢复1、2 d时间点的MT2基因表达动态。结果表明,虹鳟MT2基因CDS区长186 bp,编码62个氨基酸,具有典型的半胱氨酸(Cys)-X(1~3个)-半胱氨酸结构,属不稳定亲水性蛋白。虹鳟MT2基因序列与大西洋鲑的同源性最高且在肝脏中表达量最高,其次是脑和肠道。胁迫试验结果显示,MT2基因在肝脏和鳃中呈现先升高后降低的趋势,在头肾、脾脏和脑中呈现逐渐升高的趋势,且呈现一定的剂量依赖性,肠道MT2基因在胁迫2、3和4 d被显著抑制。胁迫恢复后,处理组肝脏、头肾、鳃、脑MT2基因表达量仍显著升高。综上,虹鳟MT2基因能在不同组织中被Cu^(2+)诱导表达,推测MT2基因在虹鳟抗重金属毒性中可能发挥着重要作用,且MT2基因表达量与铜离子的浓度相关,可以作为分子生物标志检测水域生态中的重金属铜污染。

基于植被指数与连续小波变换的玉米叶片Cu^(2+)含量反演

目的:确定Cu^(2+)污染胁迫下玉米叶片Cu^(2+)含量最优反演模型。方法:以室内盆栽玉米为研究对象,在采集不同胁迫梯度下玉米叶片光谱以及同期叶片Cu^(2+)含量的基础上,通过遍历计算出两波段原始光谱植被指数,并将其与叶片Cu^(2+)含量进行相关性分析;利用0.1~0.9阶、1.1~1.9阶与1~4阶共22种光谱微分预处理重采样后的光谱数据,经连续小波变换后分析小波系数与叶片Cu^(2+)含量之间的相关性;根据相关性分析提取最优植被指数与最优小波系数,建立反演模型。结果:植被指数与叶片Cu^(2+)含量显著相关,最优波段组合分别为:DI(621.5 nm, 1 889.2 nm)、RI(482.2 nm, 1 418.5 nm)、NDVI(666.3 nm, 1 917.2 nm)、RNDVI(621.5 nm, 1 889.2 nm),其光谱特征均集中在可见光与近红外波段附近;小波系数也与叶片Cu^(2+)含量之间具有良好的相关性,其敏感波段位于400、600、900、1 200、2 400 nm附近,与最优植被指数敏感波段一致。经0.9阶光谱微分预处理后得到的小波系数与叶片Cu^(2+)含量相关系数最大,为0.88;通过相关性分析提取最优植被指数和最优小波系数,以植被指数与不同阶微分变换的连续小波变换提取的小波系数为自变量,建立线性反演模型,其中利用最优植被指数建立的反演模型精度最高,模型最稳定,RMSE为4.97μg/g。结论:植被指数和连续小波变换两种方法在农作物重金属污染监测方面具有重要的参考价值,应用前景广阔。