EFFECTS OF CALDESMON, CALPONIN, AND TROPOMYOSIN ON THE MG^(2+)-ATPase ACTIVITIES OF SMOOTH MUSCLE MYOSIN

Objective To test whether in the absence of actin, actin-binding proteins such as caldesmon, calponin, and tropomyosin interact with the myosin of unphosphorylation, Ca 2+ -dependent phosphorylation (CDP), and Ca 2+ -independent phosphorylati-on (CIP) and stimulate myosin Mg 2+ -ATPase activities. Methods Mg 2+ -ATPase activities were measured to evaluate the effects of caldesmon, calponin, and tropomyosin on the myosin in unphosphorylation, CDP by myosin light chain kinase (MLCK), and CIP by MLCK. Results (1) At different incubation-time, i.e., 5, 10, 20, 40, and 60 minutes, the highest Mg 2+ -ATPase activity was ob-served when myosin was in the state of CDP, the medium was CIP of myosin, and the lowest was the unphosphorylated myosin. (2) In the absence of caldesmon, calponin, and tropomyosin, the Mg 2+ -ATPase activities from high to low were in the following order: CDP, CIP, and unphosphorylated myosin. However, in the presence of caldesmon, calponin, and tropo-myosin, the order of relative value of Mg 2+ -ATPase activities from high to low was unphosphorylated, CIP, and CDP of myosin respectively compared to the corresponding controls. Conclusions The results propose that caldesmon, calponin, and tropomyosin are capable of stimulating Mg 2+ -ATPase activity of smooth muscle myosin in Ca 2+ -independent manner, since Ca 2+ is not obligating for the stimulating effects of the three proteins. The common characteristic of the three proteins is that when myosin activities are low, their activations are relatively strong and this property might be involved in smooth muscle tension keeping.

The Relationship Between Senescence and Ca^(2+)-ATPase Activity of Microsomal Membrane and Lipid Peroxidation in Harvested Peach Fruit

Peach fruit easily soften and have a short storage time at normal temperature. In this study, peach fruit （Prunus persica sieb et Zucc cv. Yingqing） were picked and stored at 25 and 4℃ to investigate the senescence in correlation with Ca^2＋- ATPase activity of microsomal membrane and lipid peroxidation during ripening and senescence. In comparison with that stored at 25~C, the fruit stored at 4℃ exhibited a higher flesh firmness, lower respiration rate, and generated the late bigger peak value of Ca^2＋-ATPase activity as well as maintained the higher activity of the enzyme. Meanwhile, the lower levels of super oxygen radical （O2^-.） production and content of malondialdehyde （MDA）, a product of membrane lipid peroxidation were observed. Sodium orthovanadate （SO） and erythrosin B （EB）, as Ca^2＋-ATPase inhibitors, could stimulate the respiration rate. The results suggested that the slower senescence rate of peach fruit was closely related to the higher peak value and longer duration of Ca^2＋-ATPase activity in microsomal membrane, with the slighter membrane lipid peroxidation and lower O2^-. production rate.

The investigation for the relationship among serum leptin, erythrocyte membrane Ca^(2+)-ATPase activity and hypertensive disorder complicating pregnancy

Objective： To study the significance of Leptin and the activity of erythrocyte membrane Ca^2＋-ATPase（EMCA） in the development of hypertensive disorder complicating pregnancy. Methods： Radioimmunoassay was used to test the level of serum Leptin, and the activity of EMCA was determined chemically in 38 pregnant women with hypertensive disorder complicating pregnancy and 36 normotensive pregnant women. Results： The level of serum Leptin in hypertensive disorder complicating pregnancy（gestational hypertension： 13.76 ± 3.46 ng/ml; preeclampsia： 15.76 ± 5.47 ng/ml; eclampsia： 18.32 ± 6.38 ng/ml）was significantly higher than that in normotensive pregnant women （11.33 ± 2.93 ng/ml） ,respectively. The average EMCA activity of patients with hypertensive disorder complicating pregnancy （gestational hypertension： 1.65 ± 0.24 μmol·pi/mg.h ; preeclampsia： 1.37 ± 0.19 μ mol·pi/mg·h;eclampsia：1.12 ± 0.14 μmol·pi/mg·h） was significantly lower than that of normotensive pregnant women（1.83 ± 0.38 μ mol·pi/mg·h）,respectively. There was a negative correlation between the level of serum Leptin and the activity of RMCA in hypertensive disorder complicating pregnancy （r = -0.63）. Conclusion： Inhibition of EMCA activity of erythrocyte in hypertensive disorder complicating pregnancy may increase cytoplasmic free calcium, which contributes to the development of hypertensive disorder complicating pregnancy. The negative correlation between the level of serum Leptin and the activity of EMCA, also suggested that serum Leptin and the activity of EMCA may play a role in the development of hypertensive disorder complicating pregnancy.

博落回对大鼠心肌Ca^(2+).Mg^(2+)-ATPase与SDH活性的影响及超微结构观察

目的探讨博落回对心肌作用的机制。方法SD大鼠36只分为2个实验组和1个对照组,每组12只;2个实验组分别按1/6LD50、1/3LD50剂量的博落回水煎液灌胃,对照组以蒸馏水灌胃。各组大鼠处死后,每组10只取心肌组织制成匀浆,检测Ca2+.Mg2+-ATPase与SDH(琥珀酸脱氢酶)的活性;另2只大鼠心肌行超微结构观察。结果1/6LD50组大鼠心肌内Ca2+.Mg2+-ATPase与SDH活性较对照组有显著性升高(P<0.05);1/3 LD50组大鼠心肌内Ca2+.Mg2+-ATPase与SDH活性同对照组比较无显著性差异(P>0.05),但呈下降趋势。超微结构观察到实验组大鼠心肌细胞发生凋亡及1/3 LD50组大鼠出现心肌排列紊乱、断裂等征象。结论博落回对大鼠心肌内Ca2+.Mg2+-ATPase与SDH的活性有影响作用,并能诱导心肌细胞凋亡。

女贞子提取物对大强度耐力训练大鼠不同组织Mg^(2+)-ATPase活性的影响

分析大鼠服用女贞子提取物(Fructus Ligustri Lucidi extracts,FLLE)进行大强度耐力训练后,心、肝、脑、肾和股四头肌组织中Mg2+-ATPase活性的变化,研究FLLE作为运动补剂对大鼠运动能力的影响.把大鼠随机分为安静对照组、运动对照组和运动+FLLE组,每组8只.运动对照组进行6周大强度跑台训练,运动+FLLE组除大强度跑台训练外,每天灌服2mL 400mg/kg的FLLE,安静对照组和运动对照组每天灌服2mL 0.5%Tween-80溶液.6周后,安静组在安静时取材,运动组和运动+FLLE组进行一次力竭性运动后取材,分别测定不同组织的Mg2+-ATPase活性.实验结果显示:运动组和运动+FLLE组大鼠不同组织的Mg2+-ATPase活性均显著低于安静组,运动+FLLE组大鼠不同组织的Mg2+-ATPase活性均高于运动组(P<0.01或P<0.05);运动组大鼠与安静组相比较,其心、肝、脑、肾和股四头肌组织中Mg2+-ATPase活性分别下降21.01%、10.06%、11.15%、19.89%和12.36%;运动+FLLE组大鼠与运动组相比较,其心、肝、脑、肾和股四头肌组织中Mg2+-ATPase活性分别升高21.62%、9.21%、8.24%、21.94%和7.05%;运动+FLLE组大鼠力竭运动时间比运动对照组延长23.09%.这说明补充FLLE可以提高机体内抗氧化剂的浓度,防止细胞膜的氧化损伤,维持细胞内离子浓度稳态,保证线粒体内物质代谢和能量代谢的正常进行,使能量维持在一个较高的水平.

AMP和MH对菊花绿蕾期叶片叶绿体Ca^(2+)-ATPase、Mg^(2+)-ATPase及超微结构的影响

在秋菊姹紫嫣红品种的营养生长期,以氨卞西林钠(AMP,1 000mg/L)和不同浓度马来酰肼(MH 100mg/L、200mg/L和300mg/L)的水溶液进行叶面喷雾处理,初步研究了AMP和MH对菊花绿蕾期叶片光合速率、叶绿体Ca2+-ATPase、Mg2+-ATPase活性和叶绿体超微结构的影响。结果表明,AMP处理使菊花绿蕾期叶片上述生理指标均明显高于对照,叶绿体片层结构数量和密集程度明显增加,嗜锇颗粒减少。MH处理叶绿体Ca2+-ATPase和Mg2+-ATPase活性比对照明显降低,且随处理升高呈先降后升的变化趋势;在100~200mg/L MH浓度范围内,光合速率和叶绿体片层结构数量和密集程度均高于对照,嗜锇颗粒减少,且处理效应随处理浓度升高而有所减弱,在300mg/L处理下,光合速率低于对照且叶绿体片层结构趋于解体,嗜锇颗粒数量明显增多。

Spinosyn A对家蝇生长发育及Na^+,K^+-ATPase、Ca^(2+),Mg^(2+)-ATPase和AChE的影响

研究了Spinosyn A对家蝇(Musca domestica L.)生长发育及其Na+,K+-ATPase、Ca2+,Mg2+-ATPase和AChE的影响。结果表明,SpinosynA对家蝇有杀卵作用,且其化蛹率显著下降;SpinosynA在离体时低浓度抑制家蝇头部Na+,K+-ATPase活性而高浓度酶被激活,活体时在48h内酶活性都受到明显抑制,并随浓度升高而增强;离体时低浓度抑制家蝇Ca2+,Mg2+-ATPase活性而高浓度时酶被激活;活体时24h后该酶被激活。离体时对家蝇头部AChE有弱的抑制作用,但不同处理浓度之间无差异,而在活体时48h内能显著激活AChE活性。

海藻糖/二甲基亚砜对冷冻保存鼠皮Ca^(2+)-Mg^(2+)-ATPase的活性保护

目的:探讨海藻糖/二甲基亚砜对冷冻保存皮Ca2+-Mg2+-ATPase活性的保护作用。方法:采用Reinila方法测定冷冻保存皮Ca2+-Mg2+-ATPase活性。结果:显示鼠皮Ca2+-Mg2+-ATPase活性随海藻糖冷冻保护液浸泡时间的延长逐渐升高,在30 min时达到最高,然后逐渐下降,至50 min以后下降到60%,低于无冷冻液浸泡组。结论:海藻糖冷冻保护液浸泡30、40 min对鼠皮Ca2+-Mg2+-ATPase活性具有保护作用。

甲状腺机能减退征患者红细胞膜Ca^(2+).Mg^(2+)-ATPase活性测定

目的了解红细胞膜钙-镁三磷酸腺苷酶(Ca2+.Mg2+-ATPase)活性在甲状腺功能减退征患者中的变化及该酶活性是否随甲状腺功能的恢复而逆转至正常,以确定该酶活性可否作为甲状腺激素在细胞水平作用的一个指标。方法低温、低渗溶解红细胞,差速离心法制备红细胞膜悬液。酶活性以含酶的红细胞膜悬液水解底物ATP释放出无机磷的量表示,无钙条件下无机磷的产生量为Mg2+-ATPase活性,有钙条件下无机磷的产生量为总ATPase活性,二者之差为Ca2+.Mg2+-ATPase活性。结果甲状腺功能减退患者红细胞Ca2+.Mg2+-ATPase活性明显低于正常组。但3月后,随着甲状腺功能恢复正常,酶活性也随之恢复正常。结论红细胞膜Ca2+.Mg2+-ATPase活性可作为甲状腺激素在细胞水平作用的一个指标,用于甲状腺功能异常的辅助诊断。

Propylene Polymerization by TiCl_4 Supported on Mg(OEt)_2 Activating with Ethanol/CO_2 System

In the preparation of catalyst for propylene polymerization, the Mg(OEt) 2 support was activated with ethanol/CO 2 system followed by solidification, and treated with TiCl 4 in the presence of ethylbenzoate as an internal donor(ID). The chemical compositions of the activated support and the prepared catalyst were examined in detail. During the dissolution of Mg(OEt) 2 support in ethanol medium with CO 2 bubbling, the structure of support changed to magnesium hydrocarbyl carbonate, (CH 3CH 2O) 2- x Mg(O (C O) OCH 2CH 3) x ( x = 1,2). The content of carbonated CO 2 in the activated support was dependent on the heat treatment in the solidification of support. In the preparation procedure of polymerization catalyst, the activated support was treated with TiCl 4 so that the structure of support was converted to MgCl 2 with the incorporation of ID. The polymerization behavior of the pre-pared catalyst was also studied in the presence of phenyltriethoxysilane as an external donor.

温灸家兔穴位后循经皮肤温度及组织Ca^(2+)-、Mg^(2+)-ATP酶活性的变化

目的:研究循经温度形成的现象与Ca2+、Mg2+-ATP酶活性变化的关系,探讨循经高温线形成的能量代谢机制。方法:选用健康成年家兔7只,用红外热像仪观察温灸左后肢外侧"后三里"、右后肢内侧"阴陵泉"穴诱发胃经和脾经出现的温度变化。选取温灸后循经出现温度较高部位(高温区)的组织,用酶学方法测定Ca2+、Mg2+-ATP酶活性,并与非高温区(对照区)组织比较。结果:温灸家兔"后三里""阴陵泉"穴循经组织温度明显升高。右后肢内侧(足太阴脾经)高温区组织Mg2+-ATP酶活性明显高于对照区组织(P<0.05);左后肢外侧(足阳明胃经)高温区组织Mg2+-ATP酶活性亦有增高趋势,但与对照组比较差异无显著性意义(P>0.05)。温灸后,双后肢循经高温区组织Ca2+-ATP酶活性较对照区有升高趋势,但差异无显著性统计学意义(均P>0.05)。结论:1)家兔足太阴脾经循经出现温度较高组织的Mg2+-ATP酶活性较非高温区增强,可能导致外周ATP释放能量的功能活动加强,从而促使组织能量代谢旺盛。2)家兔循经温度较高组织的Ca2+-ATP酶活性未见明显改变,提示Ca2+-ATP酶活性在循经高温区的形成过程中可能不起主要作用。

蟾蜍毒素对S180荷瘤小鼠肉瘤细胞Mg^(2+)-ATP酶、葡萄糖-6-磷酸酶活性的影响

目的探讨醇溶性蟾蜍毒素对S180荷瘤小鼠肉瘤细胞Mg2+-ATP酶(Mg2+-ATPase)、葡萄糖-6-磷酸酶(G-6-Pase)活性的影响。方法乙醇溶解蟾蜍分泌物原浆,采用减压蒸馏等方法,进一步部分分离纯化,获得醇溶性的蟾蜍毒素混合物(Ethanol extract of toad venom,简称EET),将其作用于S180荷瘤小鼠模型,计算肿瘤抑制率,应用酶化学染色法观察S180肉瘤细胞酶活性的变化。结果蟾蜍毒素组和氟脲嘧啶组的肿瘤抑制率分别为35.6%和36.9%(P<0.05),细胞质膜标志酶Mg2+-ATPase、内质网标志酶G-6-Pase反应颗粒变小,数量减少,密度变低,提示酶活性明显下降。结论蟾蜍毒素可降低S180荷瘤小鼠肉瘤细胞质膜标志酶Mg2+-AT-Pase及内质网标志酶G-6-Pase的活性,抑制肿瘤细胞的生长。

Mg^(2+)对氧化亚铁硫杆菌生长活性的影响

研究了在常用的细菌浸出条件下 (t=30℃ ,pH 2 .0 ) ,Mg2 + 对氧化亚铁硫杆菌 (T .f)生长活性的影响。结果表明 ,该实验所用菌株具有一定的耐Mg2 + 能力 ;当培养基中 ρ(Mg2 + )≤ 10 .5 g/L时 ,Mg2 + 对细菌的生长活性没有不利的影响 ;ρ(Mg2 + ) 15 .5 g/L时对细菌生长活性的影响较明显 ;ρ(Mg2 + ) 2 0 .5 g/L时细菌的生长完全受到抑制。经驯化后的该菌株耐Mg2 + 性明显提高 ,在含 ρ(Mg2 + ) 15 .5g/L的培养基中细菌的生长活性良好。

微波辐射Mg(OH)_2制备轻质活性MgO新工艺

探讨了微波辐射Mg(OH) 2 制备轻质活性MgO的可行性 ,研究了微波功率、微波辐射时间、物料重量对Mg(OH) 2 分解率的影响 ,得到了微波辐射Mg(OH) 2 制备轻质活性MgO的最佳工艺 :微波功率 80 0W ,微波辐射时间 8分钟 ,物料重量4克 ,其煅烧时间只有传统方法的 1/10 ,Mg(OH) 2 分解率为 99.6 2 % ,氧化镁含量 95.0 9% ,碘吸附值为 78.6 8mg/g ,产品指标达到了沪Q/HG11— 2 38—

神经节苷脂（Gangliosides）对人红细胞膜Ca^（2＋）－Mg^（2＋）ATPase的影响

神经节苷脂（Ｇａｎｇｌｉｏｓｉｄｅｓ）是红细胞膜Ｃａ^（２＋）－Ｍｇ^（２＋）ＡＴＰａｓｅ的一种激活剂，这种激活作用也是依赖于Ｃａ^（２＋）存在。在２００μｍｏｌ／ＬＣａ^（２＋）存在的反应体系中，１００μｇ／ｍＬＧａｎｇｌｉｏｓｉｄｅｓ对Ｃａ^（２＋）－Ｍｇ^（２＋）ＡＴＰａｓｅ的激活作用最大，为基本酶活性的１５０％以上。实验还发现ＣａＭ拮抗剂三氟拉嗪（ＴＦＰ）、粉防已碱（Ｔｅｔ）等也同样抑制Ｇａｎｇｌｉｏｓｉｄｅｓ的这种激活作用。其抑制的ＩＣ_（５０）值为２５μｍｏｌ／Ｌ和３０μｍｏ１／Ｌ；而此浓度下抑制剂存在的反应体系中，对Ｃａ^（２＋）－Ｍｇ^（２＋）ＡＴＰａｓｅ的基本活性影响不大。

水热法制备纤维状Mg(OH)_2

在常压下、采用液相法制备Mg(OH)2试样,XRD分析表明:合适的碳酸镁的煅烧温度和时间,可获得活性氧化镁。SEM分析表明:采用活性氧化镁为镁源之一,可获得径1～2μm、长60～100μm的纤维状Mg(OH)2试样。TEM分析表明:此纤维状Mg(OH)2为单晶体。研究结果表明所填加的氧化镁的活性不同,瞬间生成Mg(OH)2沉淀的聚集成核速率就不同;并进一步影响到反应溶液中Mg-O6八面体生长基元;CaCl2的添加,会影响该生长基元在反应溶液中的扩散速率。

健康人红细胞Na~＋－K~＋ATP酶、Ca^（2＋）－Mg^（2＋）ATP酶活性

用生物化学法及荧光法测定了成年人、老年人的红细胞Ｎａ＋－Ｋ＋ＡＴＰ酶、Ｃａ２＋－Ｍｇ２＋ＡＴＰ酶活性及胞浆游离Ｃａ２＋。结果显示：老年前期组Ｎａ＋－Ｋ＋ＡＴＰ酶及Ｃａ２＋－Ｍｇ２＋ＡＴＰ酶活性均显著低于成年人组（Ｐ＜０．０５），而胞浆游离Ｃａ２＋浓度明显高于成年人组（Ｐ＜０．０５）。老年组的两个ＡＴＰ酶活性均较老年前期组低，胞浆游离Ｃａ２＋浓度高于老年前期组。上述三个指标的随龄性变化以老年前期组最明显，特别是女性。

心肺复苏后脑组织Ca^(2+)-Mg^(2+)-ATP酶活性的改变及其意义

目的：观察心肺复苏后狗脑组织Ｃａ２＋Ｍｇ２＋ＡＴＰ酶活性的改变，探讨其对脑复苏的意义。方法：静脉注射１０％氯化钾造成心搏、呼吸骤停３０分钟后，分２组进行心肺复苏，每组６只狗；第１组用传统方法，第２组用心肺转流（ＣＰＢ）法，３０分钟后观察复苏效果，并于复苏后第１０、１５、２０、２５、３０和１２０分钟时开颅，分别取大脑皮层和海马区组织，行脑组织Ｃａ２＋Ｍｇ２＋ＡＴＰ酶测定。另外，取２只正常狗脑组织作为对照。结果：第１组仅１只狗于复苏第１５分钟后一度恢复自主循环，２０分钟后瞳孔开始缩小，但３０分钟后，瞳孔再次散大，至复苏后２５分钟心搏再次停止；其余５只均未能恢复自主循环。第２组６只狗全部恢复自主循环，瞳孔缩小到正常大小，并出现对光反应。复苏后测脑组织Ｃａ２＋Ｍｇ２＋ＡＴＰ酶活性，在第１组呈递减趋势，而第２组则呈上升趋势，直至正常。２组海马区的酶活性均高于皮层区（Ｐ＜０．０１）。结论：狗心搏、呼吸骤停３０分钟后，用ＣＰＢ方法复苏，其效果明显优于常规法；心肺复苏后，其脑组织Ｃａ２＋Ｍｇ２＋ＡＴＰ酶活性的恢复将有利于改善脑细胞内Ｃａ２＋超载，阻止脑细胞不可逆死亡，恢复脑细胞功能，从而达到脑复苏。海马区比皮层区更容易复苏?

采用Mg(OH)_2调节pH值对富磷剩余污泥厌氧消化过程氮磷释放的影响

以A/O工艺排出的富磷剩余污泥为对象,通过两组厌氧消化反应器(1组目标,1组对照),对比研究了Mg(OH)2作为pH值调节剂对污泥厌氧消化过程氮磷释放的影响。结果表明,Mg(OH)2在促进污泥水解的同时,可以有效降低消化液中NH4+-N、PO34--P质量浓度。经过21 d消化,目标反应器中VSS比对照试验多削减10%,但上清液中NH4+-N、PO4--P质量浓度仅为对照的25%、10%。消化后污泥中灰分增加,导致污泥浓缩与脱水性能显著提高。

不同类型甜菜品种根中Mg^(2+)-ATP酶活性和产质量的关系

测定不同类型甜菜品种各生育时期根中Mg2+-ATP酶活性、可溶性总糖、可溶性蛋白含量和产量、含糖率。结果表明,在幼苗期和叶丛繁茂期,Mg2+-ATP活性呈先上升后下降趋势,从块根增长期直至糖分积累期,Mg2+-ATP酶的活性逐渐增强,并保持在全生育期最高水平。不同类型品种间存在差异,在各生育时期高糖型品种Mg2+-ATP酶活性较强。根中Mg2+-ATP酶活性与根中可溶性总糖呈正相关,与甜菜根的成熟进程正相关;Mg2+-ATP酶活性与可溶性蛋白质含量呈负相关,对可溶性糖的积累方面,二者的作用刚好相反。高糖型品种的可溶性总糖含量较高,相应的根中蛋白质含量很低,Mg2+-ATP酶活性较高。