植物生长调节剂“784—1”对大豆叶肉细胞超微结构的影响

本文应用植物生长调节剂“784—1”进行大豆种子浸种和拌种处理。田间试验与电镜观察结果表明,与对照组比较,叶肉细胞中的线粒体、叶绿体和叶绿体内片层结构呈增多趋势。     

小麦T型细胞质雄性不育保持系线粒体DNA片段转化不育系的初步研究

细胞质雄性不育在植物界普遍存在,其不育机理一直是人们研究的热点。采用花粉管通道法,利用T型细胞质雄性不育保持系75-3369B线粒体的基因文库,选取其中所载外源片段较大的重组子转化T型不育系小麦75-3369A,结果重组子ME252和ME317的转化后代变成可育,表明线粒体的部分片段可以使细胞质雄性不育系的育性发生转变。     

植物线粒体RNA编辑调控研究进展

植物线粒体作为细胞中半自主性细胞器之一,在植物的生长发育过程扮演重要角色,是植物的能量工厂。RNA编辑是近些年来线粒体RNA出现的一种转录后调控,是指在RNA水平进行碱基的改变,从而形成可能性质完全不同的氨基酸,因此这种修饰后的基因表达不能忠实地反映DNA信息。目前植物中的五肽重复(pentatricopeptide repeat, PPR)基因已被大量挖掘出来且相关研究结果证实RNA编辑主要发生在线粒体、叶绿体等细胞器中,并与细胞器的功能有着密切联系,相应的分子机理研究也在不断深入。本综述主要归纳植物线粒体RNA编辑的研究进展以及总结有关线粒体RNA编辑的最新研究成果,希望为后续的研究与应用提供一定的理论参考。     

Mitochondrial mechanism of hyperglycemia-induced apoptosis in primary mouse hepatocytes with steatosis

AIM: To investigate the role of high glucose in primary hepatocytes of mice fed with a high fat diet.METHODS: Male C57BL/6J mice were fed a high fat (45% of calories) diet ad libitum for 6 weeks to induce hepatic steatosis. Primary hepatocytes were isolated from the mouse liver by the 2 step collagenase perfusion method. The cells were incubated in low glucose (5 mmol/L), low glucose plus mannitol (30 mmol/L), or high glucose (35 mmol/L) DMEM medium for 12 h. The cell viability, apoptosis, mitochondrial membrane potential, and caspase enzymatic activities were measured. Furthermore, proteins related to the stress-sensitive signaling pathway of regulating high glucose-induced apoptosis in primary hepatocytes were determined by Western blotting.RESULTS: Incubation with 35 mmol/L glucose resulted in a significant decrease in cell viability and an increase in apoptosis, whereas mannitol had no significant effect on the cell viability or apoptosis. A progressive depolarization of the mitochondria, an increase in cytosol cytochrome C and a dramatic decrease in mitochondrial cytochrome C in high-glucose stressed hepatocytes were observed. The enzymatic activities of caspase-9 and caspase-3, but not caspase-8, were significantly increased in high glucose-stressed hepatocytes (P<0.05). High glucose treatment suppressed the expression of Bcl-2 and Bcl-xL, while it increased the expression of the pro-apoptotic factor Bax.CONCLUSION: High glucose stress reduces mitochondrial membrane potential, initiates mitochondria-mediated apoptotic pathways and promotes apoptosis of hepatocytes with steatosis. This may be an important pathological mechanism of hyperglycemia-induced progression of nonalcoholic fatty liver disease.     

Effect of NG-nitro-L-arginine on mitochondria in acute lung injury induced by LPS in rats

AIM: To examine the effect of nonselective nitric oxide synthase inhibitor, NG-nitro-L-arginine (L-NA), on mitochondria from acute lung injury induced by lipopolysaccharides(LPS) in rats. METHODS: The rats were randomly divided into control group, LPS injury group and L-NA treatment group. The model of acute lung injury was prepared with injection of LPS in rats. L-NA was respectively administrated through intraperitoneal injection at 3 h after injury induced by LPS. The rats were killed and the mitochondria in lung tissues were isolated by differential centrifugation. The activities of T-NOS, iNOS, ATPase, SOD and GSH-Px, and the contents of NO and MDA from mitochondria were respectively measured. The changes of ultrastructure in lung mitochondria were examined by electronic microscope after injury and L-NA treatment. RESULTS: The activities of T-NOS and iNOS were significantly increased, the activities of ATPase, SOD and GSH-Px were significantly decreased, the contents of NO and MDA were increased after acute lung injury. L-NA significantly enhanced the activities of ATPase, SOD and GSH-Px, and markedly decreased the contents of NO and MDA and the activities of T-NOS and iNOS. CONCLUSION: L-NA inhibits the activity of NOS in mitochondria, decreases the production of NO, improves mitochondria energy pump, ameliorates oxidative injury, and effectively protects lung tissue against acute lung injury induced by LPS.     

高等植物RNA编辑的研究进展

RNA编辑被认为是生命体一种新的基因加工与修饰现象,通过改变单个核苷酸使得转录的成熟RNA与模板DNA的编码序列不完全一致。RNA编辑普遍存在于陆生植物中,是高等植物线粒体和叶绿体产生功能蛋白的重要方式,本文重点概述了高等植物RNA编辑的研究进展,并对研究中有待解决的问题进行了展望。     

Host range, distribution, and natural enemies of Bemisia tabaci ‘B biotype’ (Hemiptera: Aleyrodidae) in Turkey

The whitefly Bemisia tabaci (Gennadius) has caused notable damage to vegetable and cotton crops in the eastern Mediterranean region since about 1994, and has become particularly problematic in southern Turkey beginning in 2000. The development of squash silverleaf symptoms in Cucurbita species and the unprecedented high population levels in the region suggested that the B biotype, notable for the latter phenotypes, had been introduced. To test this hypothesis and determine the host distribution of the suspect introduced B biotype and its associated natural enemies, B. tabaci immature instars and adults, and the associated natural enemies were collected from cultivated and uncultivated plant species. From the southern Turkey collections, B. tabaci was found to colonize 152 species from 43 plant families. Of the plant species upon which B. tabaci was found to reproduce, 152 of them were reported as hosts of B. tabaci in Turkey. Five species of predators and two species of parasitoids were identified as natural enemies of the B biotype of B. tabaci in southern Turkey. Using the mitochondrial cytochrome oxidase I gene all B. tabaci were identified as the B biotype of the B. tabaci complex, at 96–100% shared identity with reference B biotype sequences. Results indicate that this invasive biotype has displaced the local Turkey-cotton haplotype that was known to occur previously in southern Turkey.     

Heat-shock protein 90-dependent translocation of Akt to mitochondria mediates insulin-like growth factor 1-induced protection of rat hearts under hypothermic preservation

AIM: To investigate the effect of insulin-like growth factor 1 (IGF-1) on hypothermic preservation of rat hearts. METHODS: Isolated rat hearts were preserved in Celsior solution with or without IGF-1 (10 nmol/L) for 9 h, followed by 60 min of reperfusion. Cell apoptosis was assessed by TUNEL method. The left ventricular developed pressure (LVDP) was recorded. Total Akt protein and phosphorylation of Akt protein were detected by Western blotting. RESULTS: Compared with Celsior solution preservation group, IGF-1 significantly enhanced the LVDP recovery rate, decreased the apoptotic index, and inhibited the opening of mitochondrial permeability transition pore. IGF-1 increased the phosphorylation of Akt in 9 h of hypothemically preserved rat heart, which was inhibited by PI3K inhibitor LY294002. LY294002 also abolished the cardioprotection of IGF-1. 17-Allylamino-17-demethoxy-geldanamycin, a heat-shock protein 90 (HSP90) inhibitor, inhibited the IGF-1-induced increase in phosphorylation level of Akt and transolation to mitochondria, the improvement of cardiac functions, and the decrease in apoptosis. CONCLUSION: IGF-1 improves the cardiac functions and decreases apoptosis in the hearts under hypothermic preservation. The mechanism might involve in HSP90-dependent translocation in Akt to mitochondria.     

甘蓝种和芥菜型油菜细胞质的遗传多样性

对36份供试材料（15份甘蓝种材料、12份芥菜型油菜、4份不同细胞质类型的甘蓝型油菜、2份白菜型油菜及黑芥、埃塞俄比亚芥、芸芥各1份）进行叶绿体和线粒体SSR分析。7对多态性叶绿体特异的SSR引物在参试材料中共检测到31条多态性条带,每个位点等位基因为3~8个,平均4.43个,PIC值为0.234~0.711,平均为0.550。 2对线粒体特异的SSR引物检测到多态性条带数分别为3和5,PIC值分别为0.409和0.558。将线粒体与叶绿体的SSR标记合并,36份材料的遗传相似系数为0.538~1.000,在遗传相似系数 0.700 处,36份材料可明显分为5类,分别为芥菜型油菜、甘蓝型油菜和白菜型油菜、埃塞俄比亚芥和黑芥、甘蓝、芸芥,结果与传统的分类一致。芥菜型油菜内存在4种单倍型,而甘蓝仅有一种单倍型,芥菜型油菜材料间的细胞质遗传多样性高于甘蓝种材料间的细胞质多样性。     

Progress in mitochondrial nitric oxide synthase

Nitric oxide (NO) is an intra- and intercellular messenger with a broad spectrumof activities in the central nervous system, cardiovascular and immune systems. Mitochondrial nitric oxide synthase (mt-NOS), which might be a new form of NOS in mitochondria, has been discovered to be active in the regulation ofmitochondrial respiration, energy metabolism and many pathophysiological processes.In this review, the location, properties, physiological and pathophysiological significance of mtNOS were summarized.