家兔实验性心肌缺血的定量酶组织化学研究

目的研究心肌缺血后琥珀酸脱氢酶(SDH)、酸性磷酸酶(ACP)及线粒体腺苷三磷酸酶(mitoATPase)的情况,力求寻找一种更为理想的诊断早期心肌缺血的方法.方法结扎家兔左冠状动脉主干建立实验性心肌缺血的动物模型,常规组织学和透射电镜技术观察缺血心肌的组织学和超微结构改变,脱氢酶染色观察大体心肌的缺血情况,并分别采用硝基四氮唑蓝法、硝酸铅法和镁离子激活法研究结扎后0.5、1、2、4、8、12h左室前壁SDH、ACP以及mitoATPase水平的动态变化,显微图像分析系统测定其平均灰度值进行定量分析.结果①缺血后1h SDH活性开始降低,随着缺血时间的延长其表达水平不断下降,在1、2、4、8、12h平均灰度值分别为97.8488±8.13077、105.376±6.06887、112.584±5.18463、124.886±12.1167和144.605±13.9902(P<0.01) ②ACP活性在缺血后4h明显增强,随着缺血时间的延长其表达水平不断增强,缺血后4、8、12h平均灰度值分别为186.494±15.7005、173.158±12.6425和162.506±11.5195(P<0.01)③缺血2h后mitoATPase表达水平显著下降,其强度随着缺血时间的延长不断减低,缺血2、4、8、12h平均灰度值分别为164.153±15.6087、171.256±17.3428、183.518±18.0872和203.218±11.7952(P<0.01).结论 SDH和mitoATPase活性的不断下降及ACP活性的逐渐增强在缺血心肌细胞的演变过程中起着重要作用.     

Polymorphism of myofibrillar proteins in histochemically identified myotomal muscle fibre types of Heteropneustes fossilis (Bloch) and Labeo rohita (Hamilton)

Myofibrillar proteins in the myotomal muscle fibre types of two freshwater teleosts, Heteropneustes fossilis (Bloch) and Labeo rohita (Hamilton), were investigated. The fibre types were identified histochemically based on the reactivities of the enzymes SDH and m -ATPase. Electrophoretic analysis revealed distribution patterns of myosin light chains, tropomyosin, troponin, c - and m -protein; specific to the muscle fibre types. The results correlate well with the general pattern of myofibrillar protein distribution found in the skeletal muscles of higher vertebrates. The significance of the present findings are discussed with regard to histochemical, biochemical as well as functional properties of the muscle fibre types.     

Supply of nitrogen can reverse senescence processes and affect expression of genes coding for plastidic glutamine synthetase and lysine-ketoglutarate reductase/saccharopine dehydrogenase

Nitrogen availability has a strong influence on developmental processes in plants. We show that the time of nitrogen supply regulates the course of leaf senescence in flag leaves of Hordeum vulgare . The senescence-specific decrease in chlorophyll content and photosystem II efficiency is clearly delayed when plants are fertilised with nitrate at the onset of leaf senescence. Concurrently, the additional supply of nitrate affects expression patterns of two marker genes of nitrogen metabolism. As shown by quantitative RT-PCR analyses, senescence-specific downregulation of plastidic glutamine synthetase ( GS2 ) and senescence-specific upregulation of lysine-ketoglutarate reductase/saccharopine dehydrogenase ( LKR/SDH ) are both clearly retarded. Depletion of nitrogen in experiments using hydroponic growth systems results in premature primary leaf senescence. The already started senescence processes can be even reversed by later nitrogen addition, as proved by a further increase in photosystem II efficiency and chlorophyll content, returning to the high values of controls which had not been deprived of nitrogen. Although both addition of nitrate or ammonium effectively reversed nitrogen depletion-induced primary leaf senescence, addition of urea did not. Additionally, effects of nitrogen supply on the course of leaf senescence were analysed in the model plant Arabidopsis thaliana. Leaves of A. thaliana show the same reversion of senescence processes after receiving additional nitrogen supply, indicating that the nitrogen response of leaf development is conserved in different plant species.     

Succinate Dehydrogenase 5 (SDH5) Regulates Glycogen Synthase Kinase 3β-β-Catenin-mediated Lung Cancer Metastasis

We demonstrate that loss of succinate dehydrogenase 5 (SDH5) expression initiates epithelial-mesenchymal transition (EMT), which is visualized by the repression of E-cadherin and up-regulation of vimentin in lung cancer cell lines and clinical lung cancer specimens. In SDH5 knock-out mice, lung epithelial cells exhibited elevated mesenchymal markers, which is characteristic of EMT. Using a human lung xenograft-mouse model, we observed that knocking down endogenous SDH5 in human carcinoma cells leads to the development of multiple lymph node metastases. Moreover, our data indicate that SDH5 functions as a critical protein in regulating EMT by modulating the glycogen synthase kinase (GSK)-3β-β-catenin signaling pathway. These results reveal a critical role for SDH5 in EMT and suggest that SDH5 may be a prognostic biomarker and potential therapeutic target for lung cancer metastasis.     

甲状腺素对人体缺血/再灌注心肌能量代谢酶影响的定性定量研究

用酶组织化学方法检测了缺血／再灌注心肌ＬＤＨ、ＣＣＯ、ＳＤＨ、Ｃａ－ＡＴＰａｓｅ 活性; 分组研究甲状腺素（ＴＨ） 对围术期心肌能量代谢的影响。结果： 用药组ＳＤＨ、ＣＣＯ、Ｃａ－ＡＴＰａｓｅ 的活性比对照组增高, 两组ＬＤＨ无差异; 对照组１ 例死亡, 术前、术中、术后ＳＤＨ、ＣＣＯ、ＬＤＨ、Ｃａ－ＡＴＰａｓｅ 的活性显著降低。结论： 术前补充ＴＨ, 可提高心肌的有氧代谢, 能量合成, 促进心功能; 如果术前能了解心肌各酶活性, 将对手术适应症的选择提供帮助     

L—山梨糖脱氢酶的纯化及性质的研究

从５Ｌ罐发酵Ｌ－山梨糖的Ｇｌｕｃｏｎｉｂａｃｔｅｒ ｏｘｙｄａｎｓ ＳＣＢ３２９和Ｂａｃｉｌｌｕｓ ｔｈｕｒｉｎｇｉｅｎｓｉｓ ＳＣＢ９３３混合菌株中差速离心收集ＳＣＢ３２９菌体,破碎,离心获得无细胞抽提液,硫酸铵分级沉淀蛋白后依次经ＤＥＡＥ Ｃｅｌｌｕｌｏｓｅ ５２和Ｑ Ｓｅｐｈａｒｏｓｅ ＦＦ柱层析分得到了Ｌ－册梨糖脱氢酶（ＳＤＨ）,它能将Ｌ－册梨糖脱氢氧化为Ｌ－册梨酮,ＳＤＳ－ＰＡＧＥ电泳测     

Cell-free synthesis of succinate dehydrogenase and mitochondrial adenosine triphosphatase of sweet potato

Polyadenylated mRNA was isolated from aged slices of sweet potato root tissue and translated in a wheat germ cell-free system. The synthesis of apoprotein of the flavoprotein subunit of succinate dehydrogenase and two of the subunits of mitochondrial adenosine triphosphatase were detected by indirect immunoprecipitation. The molecular weights of the immunologically identified products were 3,000 and 8,000-9,000 daltons larger than the mature flavoprotein subunit of succinate dehydrogenase and the mature subunits of adenosine triphosphatase, respectively.     

Temporal progress of muscle adaptation to endurance training in hind limb muscles of young rats

Summary The soleus, rectus femoris and gastrocnemius muscles of young rats were studied after 3, 6 and 12 weeks of treadmill training. The muscle fibers were characterized histochemically by their succinate dehydrogenase (SDH) and myofibrillar ATPase activity, and morphometrically by their cross-sectional areas, which were corrected for different body weights of control and trained animals.After 12 weeks of training the mean area of fibers in the muscles studied was not significantly different from the controls, as expected. In the soleus muscle the percentage of the fast-twitch fibers was decreased as a result of their transformation into slow-twitch fibers. Trained soleus muscles were the only muscles showing pathologically altered fibers, suggesting overload. The percentages of fiber types and their areas exhibited changes specific for the muscles and muscle regions studied.From these results it is concluded that the adaptation follows the sequence proportional adaptation of morphometrical parameters, disproportional adaptation of the areas of fiber types, and disproportional adaptation of the percentages and/or the areas of the fiber types. It is shown by comparison with the literature that this sequence may be generalized to a sequence of increasing expense necessary for the adaptation to increasing stimuli, and that the most decisive factors for adaptation are work load, frequency of exercise, period of training, and the age of the subject at the initiation of the training.