克山病病区粮喂养大鼠后心肌细胞自由钙浓度变化与硒的作用

为了解克山病的发病机理,本文研究了低硒对心肌细胞钙转运的影响。用克山病病区粮喂养的大白鼠与用非病区粮喂养的大白鼠相比,心肌细胞胞浆自由钙的浓度高,心肌细胞膜流动性及Na~+,K~+-ATP酶活性也高,在病区粮中添加适量的硒,上述指标与用非病区粮喂养的大白鼠的差距缩小,说明低硒是引起心肌细胞钙转运失常从而使细胞浆自由钙浓度升高的重要因素但不是唯一的因素,文中讨论了细胞浆自由钙浓度与细胞膜流动性、Na~+,K~+-ATP酶活性及心肌线粒体功能的关系,以及低硒对它们的影响。     

黄皮种子线粒体呼吸速率和活性氧清除酶活性对脱水的响应及其生态学意义

顽拗性种子脱落时具有较高的含水量和代谢活性, 对脱水高度敏感; 但顽拗性种子脱水敏感性的机理至今仍然不清楚。该文以顽拗性黄皮(Clausena lansium)种子为材料, 研究了种子和胚轴对水分丧失的响应, 在脱水过程中胚轴和子叶的呼吸速率, 胚轴和子叶线粒体的细胞色素c氧化酶(CCO)活性、外膜完整性、CCO和交替氧化酶(AOX)途径以及线粒体活性氧清除酶活性的变化。结果表明, 随着水分的丧失, 种子和胚轴的存活率逐渐下降, 种子的脱水敏感性大于胚轴; 胚轴和子叶的呼吸速率以及线粒体外膜的完整性降低。胚轴和子叶线粒体的CCO途径以及胚轴AOX途径的呼吸速率在脱水初期增加, 随着继续脱水下降, 胚轴线粒体AOX途径的呼吸速率则随着脱水显著下降。胚轴线粒体的超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性和子叶线粒体的APX活性随着脱水迅速下降; 胚轴线粒体的脱氢抗坏血酸还原酶(DHAR)活性和子叶线粒体的SOD、DHAR和GR活性在脱水初期增加, 然后下降。这些数据表明黄皮种子的脱水敏感性与线粒体的呼吸速率和活性氧清除酶的活性降低密切相关, 也与长期适应热带/亚热带的生境有关。     

大豆下胚轴线粒体的衰老与膜脂的过氧化作用

离体的大豆下胚轴线粒体,在人工衰老条件下,产生了结构膨胀和细胞色素氧化酶活性的下降。衰老的线粒体也发生膜脂的过氧化作用——丙二醛、脂质的氢过氧化物和荧光脂褐色素明显增加。而且,线粒体衰老时产生的膜脂过氧化产物雨二醛,可能是膜脂的磷脂酰胆碱和磷脂酰乙醇胺中的亚麻酸发生过氧化反应的结果。     

克山病是一种“心肌线粒体病(Mitochondrial Cardiomyopathy)”

亚急克病人心肌线粒体内膜电子传递链的琥珀酸氧化酶系,琥珀酸脱氢酶和细胞色素氧化酶活性明显低于对照。H~ -ATP酶的活性及其对寡霉素的敏感性都明显下降。ATP能量化后线粒体膜电位的变化也比对照明显降低。膜脂流动性低于对照。亚急克病人心肌线粒体内观察到较多的电子致密无定形物质,经电镜X射线微区等方法分析,认为这些物质不是Ca_3(PO_4)_2,而可能是一种蛋白质凝聚物。此外,心肌线粒体的硒含量远低于对照,而Ca含量明显高于对照。上述结果都反映亚急克病人心肌线粒体明显损伤。根据克山病患者心肌细胞线粒体结构与功能方面呈现的如此广泛与明显的异常,可将克山病称为“心肌线粒体病(Mitochondrial Cardiomyopathy)”。     

大鼠心肌整体缺血及离体再灌注致生物膜的损伤作用

目的和方法：利用整体大鼠异丙肾上腺素损伤（ISO）和离体大鼠全心停灌／再灌（I／R）两种模型,观察了心肌缺血和缺血／再灌注对心肌生物膜－线粒体膜及肌纤维膜损伤的影响。结果：ISO（5mg/kg,皮下注射）和I／R（20min/20min)可导致大鼠心脏生物膜产生严重损伤,表现为心肌线粒体脂质过氧化产物明显增加,线粒体磷脂酶A2（PLA2）激活,从而导致线粒体膜磷脂（PL）含量减少,磷脂分解产物游离脂肪酸（FFA）增加,膜脂流动性（LFU）降低,线粒体Ca^2 -ATPase及肌纤维膜Na^ ,K^ -ATPase活性降低,线粒体呼吸功能降低、呼吸链氧化磷酸化解偶联,高能磷酸化合物生成减少。结论：整体ISO和离体I／R可导致大鼠心肌线粒体、肌纤维膜结构和功能损伤。     

有氧运动对高脂膳食小鼠心肌损伤中Nrf2/GPX4/Ferroptosis通路的作用*

目的: 探讨核因子E2相关因子2(Nrf 2)激活谷胱甘肽过氧化物酶4(GPX4)抑制铁死亡(Ferroptosis)的通路在有氧运动预防高脂膳食小鼠心肌损伤中的保护作用。方法: 40只5周龄SPF 级C57BL/6雄性小鼠随机分为安静对照组(NC)、运动组(NE)、高脂组(HC)和高脂+运动组(HE,高脂与跑台运动同时开始),每组10只。高脂膳食采用60% Kcal SPF级高脂模型饲料喂养,自由进食。有氧运动采用递增负荷跑台运动,每周5 d,60 min/d,速度从13 m/min开始,每两周速度递增1 m/min。14周后取心肌和血液。HE染色观察心肌组织结构变化。Western blot 检测心肌Nrf2/GPX4/ Ferroptosis相关蛋白表达。分光光度法测定心肌过氧化物浓度和抗氧化酶活性。ELISA法检测心肌线粒体8-OHdG和血清胰岛素水平。结果: 与对照组相比,高脂组的心肌纤维间隙脂质集聚增加,FBG和FINS显著增加,而ISI显著下降(P＜0.01);与高脂组相比,高脂运动组的心肌纤维间隙脂质集聚减少, T-AOC、T-SOD、GSH活性显著增强,心肌线粒体8-OHdG和心肌铁含量降低(P＜0.01),FPN1、FTH1、GPX4、GLUT1和细胞核内Nrf2显著升高(P＜0.01)。结论: 有氧运动可促进小鼠心肌Nrf2转位入核增强GPX4表达,抑制心肌Ferroptosis发生,同时促进心肌抗氧化酶活性,抑制心肌线粒体过氧化损伤。     

不同酸化条件对菜豆幼苗碳氮代谢酶系活性的影响

采用4个不同pH值(pH7,6,5,4)培养液模拟菜豆萌发和幼苗生长环境,研究了酸化条件下菜豆种子萌发和幼苗生长特性、幼苗根系和幼叶的抗氧化酶系活性以及叶片的碳氮代谢的主要酶系活性和产物水平,以期明确菜豆的碳氮代谢对酸化胁迫的响应机制。结果表明:随着pH的降低,菜豆发芽势和发芽率降低,幼苗和根系干物质量减少;谷氨酰胺合成酶活性降低,蔗糖磷酸合成酶活性增强,从而增加了蔗糖、果糖和总可溶性糖含量;根系的超氧阴离子自由基(O2ˉ·)和丙二醛(MDA)含量降低,叶片的O2ˉ·和MDA含量增加,而叶片和根系的抗氧化酶系活性同向变化,即超氧化物歧化酶和过氧化氢酶活性增强,过氧化物酶活性降低。酸化条件下,菜豆的碳代谢加强,氮代谢受到抑制;叶片过氧化物酶活性的降低和O2ˉ·含量的增加,导致了叶片膜脂过氧化程度的加剧。     

壳聚糖提高香蕉幼苗抗冷性的效应

壳聚糖(CS)预处理可降低低温胁迫下香蕉幼苗叶细胞膜脂过氧化水平和膜透性增加的程度以及超氧化物歧化酶(SOD)、过氧化物酶(POD)活性的下降幅度,提高过氧化氢酶(CAT)的活性;0.3%的壳聚糖的保护效果最好.     

克山病病区粮喂养大鼠红细胞膜脂流动性的变化

本文观察了低硒的克山病病区粮和克山病病区粮补硒后喂养大鼠对其红细胞膜脂流动性的影响。实验结果表明克山病病区粮喂养的大鼠红细胞膜脂流动性较正常对照降低,其原因可能与机体处于低硒状态下红细胞膜结合硒含量降低、红细胞膜胆固醇含量及脂质过氧化产物升高有关,克山病病区粮补硒后喂养大鼠,其红细胞膜脂流动性恢复至正常对照。     

实验性糖尿病大鼠肝过氧化物酶体脂肪酸β-氧化及D-双功能蛋白活性变化的初步研究

为研究过氧化物酶体脂肪酸β-氧化及D-双功能蛋白在糖尿病脂代谢紊乱中所起的作用,分析了链脲佐菌素诱导的糖尿病大鼠肝脏过氧化物酶体数量和过氧化物酶体脂肪酸β-氧化及D-双功能蛋白活性的改变,并用蛋白质印迹检测过氧化氢酶和D-双功能蛋白的表达量.发现糖尿病大鼠肝脏过氧化物酶体增殖,过氧化氢酶蛋白量和酶活性显著增加,过氧化物酶体脂肪酸β-氧化增强,D-双功能蛋白含量和酶活性显著降低,脂酰CoA氧化酶、L-3-羟脂酰CoA脱氢酶活性显著增加.对过氧化物酶体脂肪酸β-氧化增强和D-双功能蛋白活性降低与糖尿病脂代谢紊乱的关系进行了初步探讨.     

Keshan disease and mitochondrial cardiomyopathy

Keshan disease (KD) is a potentially fatal form of cardiomyopathy (disease of the heart muscle) endemic in certain areas of China. From 1984 to 1986, a national comprehensive scientific investigation on KD in Chuxiong region of Yunnan Province in the southwest China was conducted. The investigation team was composed of epidemiologists, clinic doctors, pathologists, biochemists, biophysicists and specialists in ecological environment. Results of pathological, biochemical and biophysical as well as clinical studies showed: an obvious increase of enlarged and swollen mitochondria with distended crista membranes in myocardium from patients with KD; significant reductions in the activity of oxidative phosphorylation (succinate dehydrogenase, cytochrome oxidase, succinate oxidase, H⁺-ATPase) of affected mitochondria; decrease in CoQ, cardiolipin, Se and GSHPx activity, while obvious increase in the Ca²⁺ content. So, it was suggested that mitochondria are the predominant target of the pathogenic factors of KD. Before Chuxiong KD survey only a few cases of mitochondrial cardiomyopathy were studied. During the multidisciplinary scientific investigation on KD in Chuxiong a large amount of samples from KD cases and the positive controls were examined. On the basis of the results obtained it was suggested that KD might be classified as a “Mitochondrial Cardiomyopathy” endemic in China. This is one of the achievements in the three years’ survey in Chuxiong and is valuable not only to the deeper understanding of pathogenic mechanism of KD but also to the study of mitochondrial cardiomyopathy in general. Keshan disease is not a genetic disease, but is closely related to the malnutrition (especially microelement Se deficiency). KD occurs along a low Se belt, and Se supplementation has been effective in prevention of such disease. The incidence of KD has sharply decreased along with the steady raise of living standard and realization of preventive measures. At present, patients of KD are very sparse. In recent years the research on the non-KD mitochondrial cardiomyopathy has progressed rapidly. Given the advances in this aspect a minireview is written to evaluate the classification of KD as a kind of mitochondrial cardiomyopathy.     

Keshan disease and mitochondrial cardiomyopathy

Keshan disease (KD) is a potentially fatal form of cardiomyopathy (disease of the heart muscle) endemic in certain areas of China. From 1984 to 1986, a national comprehensive scientific investigation on KD in Chuxiong region of Yunnan Province in the southwest China was conducted. The investigation team was composed of epidemiologists, clinic doctors, pathologists, biochemists, biophysicists and specialists in ecological environment. Results of pathological, biochemical and biophysical as well as clinical studies showed: an obvious increase of enlarged and swollen mito- chondria with distended crista membranes in myocardium from patients with KD; significant reduc- tions in the activity of oxidative phosphorylation (succinate dehydrogenase, cytochrome oxidase, succinate oxidase, H -ATPase) of affected mitochondria; decrease in CoQ, cardiolipin, Se and GSHPx activity, while obvious increase in the Ca2 content. So, it was suggested that mitochondria are the predominant target of the pathogenic factors of KD. Before Chuxiong KD survey only a few cases of mitochondrial cardiomyopathy were studied. During the multidisciplinary scientific investiga- tion on KD in Chuxiong a large amount of samples from KD cases and the positive controls were examined. On the basis of the results obtained it was suggested that KD might be classified as a “Mitochondrial Cardiomyopathy” endemic in China. This is one of the achievements in the three years’ survey in Chuxiong and is valuable not only to the deeper understanding of pathogenic mechanism of KD but also to the study of mitochondrial cardiomyopathy in general. Keshan disease is not a genetic disease, but is closely related to the malnutrition (especially mi- croelement Se deficiency). KD occurs along a low Se belt, and Se supplementation has been effective in prevention of such disease. The incidence of KD has sharply decreased along with the steady raise of living standard and realization of preventive measures. At present, patients of KD are very sparse. In recent years the research on the non-KD mitochondrial cardiomyopathy has progressed rapidly. Given the advances in this aspect a minireview is written to evaluate the classification of KD as a kind of mitochondrial cardiomyopathy.     

Cardiac cytochrome-c oxidase deficiency occurs during late postnatal development in progeny of copper-deficient rats

Although cytochrome-c oxidase (CCO) is a copper-dependent enzyme, the effect of maternal copper deficiency on the expression of CCO activity during postnatal development of the neonatal rat heart has not been investigated extensively. Here, we show that CCO activity in heart mitochondria isolated from neonates of copper-deficient dams did not exhibit significant reductions until postnatal days (PND) 15 and 21. In addition, immunoblot analysis indicated that the CCO subunit (Cox-1) was reduced on postnatal Days 10 and 21, and that Cox-4 was reduced on PND 21 in heart mitochondria of the neonates from copper-deficient dams. These findings indicate that the impairment of CCO activity in neonatal heart by maternal copper deficiency occurs late in the postnatal heart development. Furthermore, the concurrent reductions in Cox-1 and Cox-4 suggest that the impaired CCO activity reflects a CCO deficiency in heart mitochondria. CCO activity and Cox-1 in heart mitochondria were not fully restored by 6 weeks of postweaning copper repletion in the pups of copper-deficient dams. This indicates that prolonged maternal intake of moderately low dietary copper produces CCO deficiency in cardiac mitochondria of neonates during late postnatal heart development, after terminal differentiation of cardiomyocytes occurs. The resistance of CCO deficiency to repair by dietary copper supplementation may be related to the relatively slow turnover of the affected mitochondria in the terminally differentiated heart.     

GPX－abzyme对受XO／HX系统损伤的心肌线粒体的保护作用

探讨了研制的具有谷胱甘肽过氧化物酶活力的含硒抗体酶（ＧＰＸ－ａｂｚｙｍｅ）对于受损心肌线粒体的保护作用,利用牛的心肌线粒体为实验材料,通过线粒体的膨胀度、脂质过氧化物含量、ＣＣＯ活力变化及电镜观察等几个方面证明ＧＰＸ－ａｂｚｙｍｅ能抵抗ＸＯ／ＨＸ系统产生的自由基的损伤作用,ＥＳＲ研究也表明ＧＰＸ－ａｂｚｙｍｅ能明显降低ＸＯ／ＨＸ损伤系统中的自由基含量。     

The membrane phospholipid cardiolipin plays a pivotal role in bile acid adaptation by Lactobacillus gasseri JCM1131T

Bile acids exhibit strong antimicrobial activity as natural detergents, and are involved in lipid digestion and absorption. We investigated the mechanism of bile acid adaptation in Lactobacillus gasseri JCM1131^T. Exposure to sublethal concentrations of cholic acid (CA), a major bile acid in humans, resulted in development of resistance to otherwise-lethal concentrations of CA by this intestinal lactic acid bacterium. As this adaptation was accompanied by decreased cell-membrane damage, we analyzed the membrane lipid composition of L. gasseri. Although there was no difference in the proportions of glycolipids (~70%) and phospholipids (~20%), adaptation resulted in an increased abundance of long-sugar-chain glycolipids and a 100% increase in cardiolipin (CL) content (to ~50% of phospholipids) at the expense of phosphatidylglycerol (PG). In model vesicles, the resistance of PG vesicles to solubilization by CA increased with increasing CL/PG ratio. Deletion of the two putative CL synthase genes, the products of which are responsible for CL synthesis from PG, decreased the CL content of the mutants, but did not affect their ability to adapt to CA. Exposure to CA restored the CL content of the two single-deletion mutants, likely due to the activities of the remaining CL synthase. In contrast, the CL content of the double-deletion mutant was not restored, and the lipid composition was modified such that PG predominated (~45% of total lipids) at the expense of glycolipids. Therefore, CL plays important roles in bile acid resistance and maintenance of the membrane lipid composition in L. gasseri.     

The Relationship Between the Metal Clusters and the Conformation of Molybdenum-Iron Protein from Azotobacter vinelandii

The ultraviolet CD spectrum of nitrogenase MoFe protein from Azotobacter vinelandii had a negative trough with double peaks at 208 nm and 222 nm, respectively, and the shape of the trough was similar to those of other proteins with a-helix structure. After treatment with o-phenanthroline under an aerobic or anaerobic condition, the height of the peak at 222 nm (h222 nm) decreased with the decrease of the C2H2-reduction activity, Fe content and CD spectra at both 450 nm and 660 nm, or at 450 nm of the treated proteins. However, after reconstituting with a reconstituent solution containing Na2MoO4, Na2S, dithiothreitol and either ferric homocitrate or ferric citrate, the h222 nm Of the reconstituted proteins could be restored as well as the activity, Fe content and CD spectra at both of 450 nm and 660 nm. The results show that there is a significant relationship between the metal clusters (FeMoco and P-cluster) and the conformation of MoFe protein.     

Analysis of glutathione peroxidase 1 gene polymorphism and Keshan disease in Heilongjiang Province, China

Keshan disease (KD) is an endemic cardiomyopathy associated with selenium deficiency. Recent studies indicate that glutathione peroxidase 1 (GPx1) mutation decreases GPx activity in myocardial cells and increases the risk of KD. To further clarify the correlation between GPx1 polymorphism and KD, we analyzed GPx1 polymorphism, blood selenium levels and GPx activity in KD patients and healthy controls in Heilongjiang Province. Four and 24 new mutation loci in the promoter and the exon region, respectively, of the GPx1 gene were found in the subjects, in contrast with the previously reported loci. There were no significant differences in the mutation frequency of these loci between the KD group and controls (chi-square test; P > 0.05). However, the mutation frequency of exon 474 was higher in the KD group (7/36) than in controls (2/41), and GPx activity was lower in the mutation group (90.475 ± 23.757 U/L) than in the non-mutation group (93.947 ± 17.463 U/L). Further investigation is necessary to clarify a possible causality between GPx1 exon 474 mutation and KD.     

克山病病区粮低Se对大白鼠心肌线粒体Ca转运影响的研究

以低Ｓｅ克山病病区粮喂养大白鼠为动物模型,在细胞及亚细胞水平上进行了低Ｓｅ与Ｃａ转运关系的研究,同时测定了线粒体的能量转换功能。结果显示,低Ｓｅ病区粮组动物心肌线粒体Ｃａ转运呈现明显异常,但线粒体能量转换功能尚未发生明显改变。提示线粒体Ｃａ转运功能损伤先于线粒体能量转换功能损伤之前发生。心肌线粒体Ｃａ转运功能可作为更灵敏的指标用于克山病发病机理的研究。上述结果进一步表明克山病是一种“心肌线粒体病”。