Ca^2＋预处理对热胁迫下辣椒叶肉细胞中Ca^2＋—ATP酶活性的影响

在常温下生长的辣椒（Capsicum annuum L.）叶肉细胞中Ca^2 －ATP酶主要分布于质膜、液泡膜上,叶绿体的基质和基粒片层上也有少量分布;在40℃下热胁迫不同的时间,酶活性逐渐下降,直到叶绿体超微结构解体。同样条件下,经过Ca^2 预处理后,分布在上述细胞器膜或片层上的酶活性大大提高,表明Ca^2 预处理对该活性具有激活作用;Ca^2 预处理对热胁迫下的超微结构的完整性具有一定的保护作用,并且能使Ca^2 －ATP酶在热胁迫下维持较高活性。结果表明,Ca^2 预处理增强辣椒幼苗的抗热性,可能与其稳定细胞膜、从而使Ca^2 －ATP酶在热迫下保护较高活性有一定关系。     

甲基紫精对水稻幼苗根细胞膜微囊Ca2+-ATP酶活性的影响

10μmool/L甲基紫精(MV)预处理水稻幼苗可明显提高其抗冷力,但这种功效可被钙的螯合剂EGTA(10 mmol/L)和钙调素(CaM)的抑制剂氯丙嗪(CPZ,0.5 mmol/L)所抑制.MV预处理提高了幼苗质膜、液泡膜Ca2+-ATP酶活性,同时也有提高质膜Fe(CN)3-6还原速率和这些活性的冷适应性,但这些效果均可被EGTA和CPZ所抑制.离体条件下,膜微囊的Ca2+-ATP酶活性对H2O2、O-2、-OH敏感.结果显示,MV预处理提高幼苗的抗冷力可能是通过钙信使介导起作用的,钙信使或CaM可能刺激了质膜、液泡膜Ca2+-ATP酶活性;而该预处理有增加质膜、液泡膜Ca2+-ATP酶的冷稳定性则可能与该处理有提高细胞抗氧化能力、稳定冷胁迫下细胞膜系统结构有关.     

草酸处理对热胁迫下辣椒叶片膜透性和钙分布的影响

研究了外源草酸对热胁迫下辣椒叶片中细胞膜相对透性、谷胱甘肽(GSH)和抗坏血酸(AsA)含量变化以及Ca2+分布的影响.结果表明热胁迫使叶肉细胞膜相对透性升高,草酸处理则减轻升高幅度.热胁迫使叶片中GSH和AsA含量下降;草酸处理则使二者在热胁迫下含量下降幅度较小.常温下辣椒叶肉细胞的焦锑酸钙沉淀颗粒主要分布于液泡、胞间隙和叶绿体中,热胁迫下液泡、细胞间隙中减少,但在细胞核和细胞质中出现;经过草酸处理的叶肉细胞,焦锑酸钙沉淀颗粒在胞间隙中明显增多,液泡中减少.     

大豆异黄酮对围绝经期大鼠卵巢Bax mRNA表达和Ca2+-ATP酶活性的影响

目的：观察大豆异黄酮（SI）对围绝经期大鼠卵巢BaxmRNA表达和Ca^2＋-ATP酶活性的影响。方法：采用自然老化法建立围绝经期大鼠动物模型。12月龄的初老雌性Wistar大鼠,分别给予低（50mg／kg）、中（158mg／kg）、高（500mg／kg）剂量SI灌胃处理8周。采用RT—PCR检测卵巢BaxmRNA的表达;采用化学比色法检测卵巢Ca^2＋-ATP酶活性、血清丙二醛（MDA）含量和超氧化物岐化酶（SOD）活性。结果：SI处理可使初老大鼠卵巢BaxmRNA表达和血清MDA含量降低,卵巢Ca^2＋-ATP酶活性和血清SOD活性明显升高（P〈0．05或P〈0、01）。结论：大豆异黄酮下调衰老卵巢BaxmRNA表达,提高细胞Ca2^2＋-ATP酶活性,可能是改善围绝经期卵巢功能的机制之一。     

NaHCO3胁迫下星星草根中Ca2+与Ca2+-ATPase 的超微细胞化学定位

利用焦锑酸盐和磷酸铅沉淀技术分别对NaHCO₃胁迫条件下星星草(Puccinellia tenuiflora)根中Ca²⁺和Ca²⁺-ATPase 进行超微细胞化学定位研究, 旨在进一步探讨Ca²⁺在NaHCO₃胁迫诱导胞内信号转导过程中的作用, 以及Ca²⁺-ATPase活性定位变化与NaHCO₃胁迫下星星草抗盐碱能力的关系。结果表明: 在正常状态下, 根毛区细胞质内Ca²⁺较少, 主要位于质膜附近和液泡中, Ca²⁺-ATPase主要定位于质膜和液泡膜, 有一定活性。在0.448%NaHCO₃胁迫下, 根毛区细胞质中Ca²⁺增多, 液泡中Ca²⁺减少, 且主要集中于液泡膜附近, 质膜和液泡膜Ca²⁺-ATPase活性明显升高。在1.054%NaHCO₃胁迫下,细胞质中分布的Ca²⁺增多, 而液泡中Ca²⁺极少, Ca²⁺-ATPase活性也降低。以上结果表明, Ca²⁺亚细胞定位和Ca²⁺-ATPase活性变化在星星草响应NaHCO₃胁迫的信号传递过程中具有重要作用。     

干旱胁迫下Ca2+·CaM信使系统对稻苗保护酶活性的影响

以氯丙嗪(CPZ)和LaCl3对水稻幼苗根际预处理,阻断其Ca2+·CaM信使系统传导后,研究了干旱胁迫下稻苗膜脂过氧化和保护酶活性的变化.结果表明干旱胁迫下,LaCl3和CPZ根际预处理显著加剧稻苗膜脂过氧化,加剧过氧化氢酶(CAT)活性和抗坏血酸过氧化物酶(APX)活性下降,对胁迫前期超氧化物岐化酶(SOD)和过氧化物酶(POD)活性无显著影响,且CPZ和LaCl3预处理加剧CAT和APX活性下降与加剧稻苗MDA含量积累分别呈极显著和显著正相关.这些结果暗示Ca2+·CaM信使系统可能主要通过调节或影响CAT和APX活性而调节稻苗的抗旱性.     

低温、高pH胁迫对水稻幼苗根系质膜、液泡膜ATP酶活性的影响

以耐冷性不同的两个水稻品种为材料,比较研究了幼苗根系质膜、液泡膜ATP酶对低温(8℃)及高pH(8.0)胁迫的反应。结果表明水稻根细胞质膜和液泡膜上均存在Ca3+-ATP酶,但活性远低于H+-ATP酶。耐冷品种武育粳3号经低温(8℃)处理2d,根系质膜和液泡膜H+-ATP酶、Ca2+-ATP酶活性均明显升高,至冷处理12d,H+-ATP酶、Ca2+-ATP酶活性有所下降,但仍与对照相近;而冷敏感品种汕优63经低温(8℃)处理2d,根系质膜H+-ATP酶活性略有升高,而质膜Ca2+-ATP酶以及液泡膜H+-ATP酶、Ca2+-ATP酶活性已明显下降;至冷处理12d,4种酶活性均明显低于对照。高pH胁迫使质膜和液泡膜H+-ATP酶活性下降,而使Ca2+-ATP酶活性上升。高pH胁迫会加剧低温冷害。结果表明,耐冷品种质膜、液泡膜ATP酶比冷敏感品种对低温胁迫有更强的适应能力。     

毛竹"韧皮部结"发育过程中Ca2+-ATP酶的超微定位

用电镜和细胞化学技术对毛竹[Phyllostachys edulis（Carr.）H.De Lehaie]节部“韧皮部结”发育过程中Ca^2＋-ATP酶进行了超微细胞化学定位研究.结果显示：在“韧皮部结”形成期,仅细胞质膜和细胞核上具有很高的Ca^2＋-ATP酶活性;随着“韧皮部结”的发育,发育期细胞质膜上的Ca^2＋-ATP酶活性较形成期有所降低,而细胞核上仍保持较高的Ca^2＋-ATP酶活性,胞间连丝、运输小泡膜上都具有Ca^2＋-ATP酶活性;发育后期,液泡膜及内质网上也开始出现Ca^2＋-ATP酶沉积物;成熟期的“韧皮部结”细胞质膜上的Ca^2＋-ATP酶活性较发育期有所升高,并且在“韧皮部结”成熟的过程中,细胞核、内质网、胞间连丝、质体膜和细胞质降解物上始终都有较高的Ca^2＋-ATP酶活性.实验结果表明“韧皮部结”细胞具有活跃的生理代谢以及频繁的共质体运输和信息交流.     

辣椒碱对小菜蛾的驱避活性及其体内谷胱甘肽-S-转移酶和Na+，K+-ATP酶活性的影响

采用常规生测方法和酶活力测定方法,初步研究了辣椒碱对小菜蛾Plutella xylostella L.的产卵忌避和拒食作用,及其对小菜蛾体内谷胱甘肽-S-转移酶、Na⁺,K⁺-ATP酶活性的影响,以期阐明辣椒碱对害虫的作用机制。结果表明,辣椒碱对小菜蛾表现出较强的产卵忌避活性和拒食活性。在6.25×10⁴ mg/L浓度下,处理24 h辣椒碱对小菜蛾的非选择性产卵忌避率达96.55%,选择性产卵忌避率为84.30%;在相同浓度下,处理48 h辣椒碱对小菜蛾的非选择性拒食率达81.47%,选择性拒食率为69.69%。 另外,经1.25×10⁵ mg/L辣椒碱不同时间处理后,小菜蛾体内的谷胱甘肽-S-转移酶酶活力和Na⁺,K⁺-ATP酶活力与对照相比均产生了波动,处理18 h时小菜蛾体内GSTs活力最高,为152.01 U·mg^-1pro·min^-1,处理1 h时小菜蛾体内Na⁺,K⁺-ATP酶活力最高,为19.99 U·mg^-1pro·min^-1。结果说明辣椒碱能够影响小菜蛾产卵和取食行为,并且对其体内的酶系也产生了影响。     

Ca2+在植物盐胁迫响应机制中的调控作用

对植物而言,Ca2+不仅作为一种必须的营养元素,更重要的是作为耦联胞外信号与胞内生理反应的第二信使,当植物受到外界的环境刺激时,细胞中Ca2+会出现变化,引起一系列保护性生理反应,从而减轻环境胁迫对植物体的伤害.我国盐碱地面积广阔,极大地限制了作物种植和农业生产.大量研究表明,Ca2+可以提高植物对盐胁迫的抗性,针对盐胁迫对植物的伤害机制,重点讨论了盐胁迫条件下Ca2+参与的植物体内有关响应途径及作用机制.     

NaHCO3胁迫下星星草根中Ca2＋与Ca2＋-ATPase的超微细胞化学定位

利用焦锑酸盐和磷酸铅沉淀技术分别对NaHCO3胁迫条件下星星草（Puccinellia tenuiflora）根中Ca2＋和Ca2＋-ATPase进行超微细胞化学定位研究,旨在进一步探讨Ca2＋在NaHCO3胁迫诱导胞内信号转导过程中的作用,以及Ca2＋-ATPase活性定位变化与NaHCO3胁迫下星星草抗盐碱能力的关系。结果表明：在正常状态下,根毛区细胞质内Ca2＋较少,主要位于质膜附近和液泡中,Ca2＋-ATPase主要定位于质膜和液泡膜,有一定活性。在0.448%NaHCO3胁迫下,根毛区细胞质中Ca2＋增多,液泡中Ca2＋减少,且主要集中于液泡膜附近,质膜和液泡膜Ca2＋-ATPase活性明显升高。在1.054%NaHCO3胁迫下,细胞质中分布的Ca2＋增多,而液泡中Ca2＋极少,Ca2＋-ATPase活性也降低。以上结果表明,Ca2＋亚细胞定位和Ca2＋-ATPase活性变化在星星草响应NaHCO3胁迫的信号传递过程中具有重要作用。     

Ca^2＋对小麦萌发及幼苗抗盐性的效应

以冬小麦（Triticum aestivum）临远077038为材料, 研究了施入外源Ca^2＋对150、200、250及350 mmol·L^-1NaCl胁迫下小麦种子萌发及幼苗生长发育的影响。结果表明： 20 mmol·L^-1CaCl2浸种能够提高小麦在150–250 mmol·L^-1盐胁迫下种子的发芽率, 并能增强其生长势; 当NaCl浓度为350 mmol·L^-1时, 小麦种子不能萌发, 且在以上浓度的NaCl胁迫下, 小麦种子均不能发育成苗。对NaCl胁迫下的小麦幼苗施入外源Ca^2＋后, 提高了幼苗膜稳定性, 降低了膜脂过氧化程度, 从而减轻了盐胁迫对幼苗膜的伤害, 表现为电导率降低、MDA含量降低及SOD和POD活性提高, 并且提高了幼苗的呼吸强度及叶绿素含量, 促进了幼苗生长及生物量的积累; Ca^2＋的缓解效应随着盐胁迫的加剧逐渐减弱, 在浓度为350 mmol·L^-1的盐胁迫下, 幼苗的生物量显著低于对照。以上结果表明, 与水处理相比, 20 mmol·L^-1CaCl2处理能够更大程度地促进小麦的生长发育。     

钙肥对富士苹果品质及Ca2+-ATPase活性影响的研究

以盛果期的矮化富士为材料,研究了不同钙肥对富士苹果品质和Ca2+-ATPase活性的影响.结果表明,喷钙后单果重增加,Vc含量提高,可溶性固形物和花青苷含量增大,而成熟果实的叶绿素和可滴定酸含量下降.不同钙肥效果顺序为巨金钙>氨基酸钙>翠康钙宝>钙宝2000.钙肥对Ca2+-ATPase活性影响极为显著,其活性明显高于对照,不同钙肥间Ca2+-ATPase活性的变化趋势与果实品质的变化趋势相同.     

Diabetes-induced decrease in rat brain microsomal Ca2+-ATPase activity

The Ca(2+)-ATPase activity of rat brain microsomes was studied in streptozotocin (STZ)-induced diabetes. Male rats, 200-250 g, were rendered diabetic by injection of STZ (45 mg kg(-1) body weight) via the teil vein. Brain tissues were collected at 1, 4 and 10 weeks after diabetes was induced for determination of Ca(2+)-ATPase activity, lipid peroxidation and tissue calcium levels. Diabetic rats had significantly elevated blood glucose levels compared to controls. Blood glucose levels were 92.92 +/- 1.22 mg dl(-1) (mean +/- SEM) for the control group, 362.50 +/- 9.61 mg dl(-1) at 1 week and >500 mg dl(-1) at 4, 8 and 10 weeks for the diabetics. Enzyme activities were significantly decreased at 1, 4, 8 and 10 weeks of diabetes relative to the control group (p < 0.001). Ca(2+)-ATPase activity was 0.084 +/- 0.008 U l(-1), 0.029 +/- 0.005 U l(-1), 0.029 +/- 0.006 U l(-1), 0.033 +/- 0.003 U l(-1) and 0.058 +/- 0.006 U l(-1) (mean +/- SEM) at control, 1, 4, 8 and 10 week of diabetes respectively. The change in calcium levels in diabetic rat brain at 8 and 10 weeks of diabetes was significantly higher than that of the control group (p < 0.05). On the other hand lipid peroxidation measured as TBARS (thiobarbituric acid reactive substances) was significantly higher at 8 and 10 weeks of diabetes (p < 0.05). The increase in lipid peroxidation observed in diabetic rat brain may be partly responsible for the decrease in calcium ATPase activity.     

高温胁迫对花生幼苗光合速率、叶绿素含量、叶绿体Ca2+-ATPase、Mg2+-ATPase及Ca2+分布的影响

将水培后盆栽的花生幼苗,置于培养箱42℃高温培养,定时测定幼苗叶光合速率、叶绿素含量和叶绿体Ca2 -ATPase、Mg2 -ATPase的相对活性,并观察幼叶细胞内Ca2 分布的变化。试验结果表明:高温胁迫过程中,光合速率及叶绿素含量都随处理时间的延伸而下降,并呈显著正相关;叶绿体Ca2 -ATPase和Mg2 -ATPase高温胁迫过程中相对活性呈先升后降趋势,Ca2 -ATPase热敏性高于Mg2 -ATPase;高温胁迫过程中,Ca2 具有从胞外转运到胞质内和叶绿体中的趋势,Ca2 能够稳定高温胁迫下叶肉细胞膜和叶绿体的超微结构。     

Thermal analysis of the plasma membrane Ca2+-ATPase

The plasma membrane Ca²⁺-ATPase is a well known enzyme in eucaryotes able to extrude calcium to the extracellular space in order to restore intracellular calcium to very low levels. This ATPase needs plasma membrane lipids such as acidic phospholipids in order to maintain its activity. In this study, we investigated the role that calcium and cholesterol play on the thermal stability of the Ca²⁺-ATPase isolated from cardiac sarcolemma and erythrocyte membranes. Calcium showed a stabilizing and protective effect when the enzyme was exposed to high temperatures. This stabilizing effect showed by calcium was potentiated in the presence of cholesterol. These protection effects were reflected on several thermodynamic parameters such as T₅₀, H_vh and apparent G, indicating that calcium might induce a conformational change stabilized in the presence of cholesterol that confers enzyme thermostability. The effect shown by cholesterol on H_vh and apparent H open the possibility that this lipid decreases cooperativity during the induced transition. Despite that a binding site for cholesterol has not been identified in the plasma membrane Ca²⁺-ATPase, our results supports the proposal that this lipid interacts with the enzyme in a direct fash     

The plant Ca2+ -ATPase repertoire: biochemical features and physiological functions

Ca(2+)-ATPases are P-type ATPases that use the energy of ATP hydrolysis to pump Ca(2+) from the cytoplasm into intracellular compartments or into the apoplast. Plant cells possess two types of Ca(2+) -pumping ATPase, named ECAs (for ER-type Ca(2+)-ATPase) and ACAs (for auto-inhibited Ca(2+)-ATPase). Each type comprises different isoforms, localised on different membranes. Here, we summarise available knowledge of the biochemical characteristics and the physiological role of plant Ca(2+)-ATPases, greatly improved after gene identification, which allows both biochemical analysis of single isoforms through heterologous expression in yeast and expression profiling and phenotypic analysis of single isoform knock-out mutants.     

Regucalcin increases Ca2+-ATPase activity in the mitochondria of brain tissues of normal and transgenic rats

The role of regucalcin, which is a regulatory protein in intracellular signaling, in the regulation of Ca(2+)-ATPase activity in the mitochondria of brain tissues was investigated. The addition of regucalcin (10(-10) to 10(-8) M), which is a physiologic concentration in rat brain tissues, into the enzyme reaction mixture containing 25 microM calcium chloride caused a significant increase in Ca(2+)-ATPase activity, while it did not significantly change in Mg(2+)-ATPase activity. The effect of regucalcin (10(-9) M) in increasing mitochondrial Ca(2+)-ATPase activity was completely inhibited in the presence of ruthenium red (10(-7) M) or lanthanum chloride (10(-7) M), both of which are inhibitors of mitochondrial uniporter activity. Whether the effect of regucalcin is modulated in the presence of calmodulin or dibutyryl cyclic AMP (DcAMP) was examined. The effect of regucalcin (10(-9) M) in increasing Ca(2+)-ATPase activity was not significantly enhanced in the presence of calmodulin (2.5 microg/ml) which significantly increased the enzyme activity. DcAMP (10(-6) to 10(-4) M) did not have a significant effect on Ca(2+)-ATPase activity. The effect of regucalcin (10(-9) M) in increasing Ca(2+)-ATPase activity was not seen in the presence of DcAMP (10(-4) M). Regucalcin levels were significantly increased in the brain tissues or the mitochondria obtained from regucalcin transgenic (RC TG) rats. The mitochondrial Ca(2+)-ATPase activity was significantly increased in RC TG rats as compared with that of wild-type rats. This study demonstrates that regucalcin has a role in the regulation of Ca(2+)-ATPase activity in the brain mitochondria of rats.     

高温胁迫对花生幼苗光合速率、叶绿素含量、叶绿体Ca2+-ATPase、Mg2+-ATPase及Ca2+分布的影响

将水培后盆栽的花生幼苗,置于培养箱42℃高温培养,定时测定幼苗叶光合速率、叶绿素含量和叶绿体Ca^2＋-ATPase、Mg^2＋-ATPase的相对活性,并观察幼叶细胞内Ca^2＋分布的变化。试验结果表明：高温胁迫过程中,光合速率及叶绿素含量都随处理时间的延伸而下降,并呈显著正相关;叶绿体Ca^2＋-ATPase和Mg^2＋-ATPase高温胁迫过程中相对活性呈先升后降趋势,Ca^2＋-ATPase热敏性高于Mg^2＋-ATPase;高温胁迫过程中,Ca^2＋具有从胞外转运到胞质内和叶绿体中的趋势,Ca^2＋能够稳定高温胁迫下叶肉细胞膜和叶绿体的超微结构。