土槿皮乙酸B通过活性氧和有丝分裂原蛋白激酶诱导MCF-7细胞凋亡的研究

土槿皮乙酸B(PAB)通过活性氧诱导肿瘤细胞MCF-7凋亡,同时也通过调控有丝分裂原蛋白激酶(MAPK)家族蛋白来调控凋亡,但活性氧和MAPK的关系还不清楚,本研究探讨活性氧和MAPK家族蛋白的关系。4 μmol/L PAB在36 h诱导细胞死亡,活性氧清除剂抑制PAB的作用,并降低PAB的抑制率;同时,PAB促进JNK磷酸化,抑制ERK的磷酸化,此作用被活性氧清除剂抑制。     

Dietary carotenoids regulate astaxanthin content of copepods and modulate their susceptibility to UV light and copper toxicity

High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC(50) values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers.     

烟草赤星病菌代谢产物对烟草BY-2细胞ROS爆发和ATP损耗的诱导?

 【目的】本文以烟草BY-2细胞为实验材料,探讨赤星病菌代谢产物（metabolic products of Alternaria alternata,MP）对烟草BY-2细胞活性氧（reactive oxygen species,ROS）产生和ATP含量变化的影响以及产生这种影响的原因。【方法】用10% MP处理烟草BY-2细胞,用氧电极检测不同时间MP处理后,烟草BY-2细胞呼吸速率和呼吸途径的变化,同时分析BY-2细胞内H2O2产生和ATP含量等的变化。【结果】 MP处理导致了烟草BY-2细胞H2O2爆发和ATP含量下降,此外MP处理也导致了烟草BY-2细胞总呼吸速率、细胞色素途径（cytochrome pathway）和及交替氧化酶途径（AOX）的下降,并且造成线粒体渗透转换孔（permeability transition pore,PTP）开放和细胞色素c释放。【结论】 MP对BY-2细胞呼吸速率和细胞色素途径的抑制不可避免地导致胞内ATP含量下降,此外MP诱导的烟草BY-2细胞氧化磷酸化的解偶联作用是MP导致胞内ATP含量下降的另一重要原因。而MP对 AOX途径的抑制则是诱导胞内ROS爆发的重要原因。     

植物线粒体中活性氧的产生及其抗氧化系统

线粒体是活性氧（reactive oxygen species,ROS）产生的主要器官之一,而ROS在植物的生长发育和胁迫响应中具有重要作用。一方面ROS作为信号分子介导植物对各种外界刺激产生胁迫响应,另一方面作为强氧化剂攻击植物体内的细胞膜或大分子物质。为了维持线粒体内ROS的动态平衡,严格控制其产生是必要的。该文综述了植物线粒体中活性氧的产生机制和途径,以及线粒体对活性氧的防御系统,包括氧化前防御和氧化后防御机制,为今后该领域的研究奠定基础。      

Signals that stop the rot: Regulation of secondary metabolite defences in cereals

Plants accumulate a vast arsenal of chemically diverse secondary metabolites for defence against pathogens. This review will focus on the signal transduction and regulation of defence secondary metabolite production in five food security cereal crops: maize, rice, wheat, sorghum and oats. Recent research advances in this field have revealed novel processes and chemistry in these monocots that make this a rich field for future research.     

A critical analysis of phosphatidic acid mediated resistance response in Sinapis alba against Alternaria brassicicola

The enhanced expression of PLD genes and the quantitative increase in the level of phosphatidic acid (PA) in resistant Sinapis alba compared to the downregulated or unchanged expression of the PLD genes and decreased PA level in susceptible Brassica juncea when challenged with Alternaria brassicicola, indicated a positive relationship between PA-mediated signalling and resistance against this necrotrophic pathogen. Furthermore, spraying PA onto the susceptible species B. juncea increased resistance and enhanced expression of ABA-responsive genes, which was comparable to the expression of these genes in S. alba when challenged with A. brassicicola.

• •The enhanced expression of several PLD genes in resistant S. alba was observed compared to B. juncea upon challenge with A. brassicicola.
• •An increase in the PA level in S. alba compared to B. juncea following interaction with the pathogen.
• •Leaves of B. juncea incubated on PA-soaked filter paper did not show resistance.
• •Spraying B. juncea leaves with PA led to resistance as well as to the enhanced expression of ABA-responsive genes.
• •A temporal increase in the PA level is associated with increased resistance against A. brassicicola.

     

一氧化氮在植物抗逆境信号转导中的作用

概述了NO分子在植物体内的来源,在信号转导、生物和非生物胁迫响应等过程中作用,以及NO与植物中其他信号分子的关系。     

高温及氧化应激对体外培养肉鸡骨骼肌线粒体功能的影响

【目的】研究高温和氧化应激对体外培养肉鸡骨骼肌线粒体功能的影响,初步探讨高温影响肉鸡肌肉品质的机制。【方法】从16只2周龄AA肉鸡的左右小腿后侧分离腓骨长肌,使用不锈钢支架维持肌肉束的正常长度,在95%O2、5%CO2混合气体饱和条件下,体外孵育2 h。分别测定升高孵育温度或在培养介质中添加邻苯三酚后,肉鸡腓骨长肌线粒体活性氧（ROS）产量、钙泵（Ca2＋-ATPase）活性和乳酸含量的变化。【结果】升高培养温度显著提高肉鸡骨骼肌线粒体H2O2的产生量（P＜0.0001）,导致肌肉脂质过氧化（P＝0.0368）,抑制线粒体钙泵活性（P＝0.0001）,增加乳酸积聚（P＜0.0001）,并影响肌纤维膜的完整性,使肌酸激酶（CK）和乳酸脱氢酶（LDH）的流失量增加（P =0.0009,P =0.0114）,而培养介质中添加邻苯三酚对肉鸡腓骨长肌产生相似的影响。【结论】高温影响线粒体功能,增加肌肉乳酸浓度,损伤肌纤维膜完整性,这些影响与高温诱导的氧化应激有关。     

NaCl胁迫对耐盐性不同葡萄株系叶片活性氧代谢及清除系统的影响

探究耐盐性不同的葡萄株系叶片活性氧产生及其清除系统对盐胁迫的响应,以期揭示耐盐性较强的葡萄种间杂交F1代株系的耐盐机制。采用组培苗营养液培养方式,以山葡萄‘左山一’与砧木SO4杂交初选的耐盐性较强的F1代株系（A15、A17）为试材,以1103P为参照品种,进行100 mmol · L-1 NaCl处理,测定各株系叶片的 产生速率、H2O2含量、相对电导率、MDA含量和叶绿素含量以及抗氧化酶活性和抗氧化物质含量等指标,并观察叶绿体超微结构。结果表明,100 mmol · L-1 NaCl胁迫下,耐盐性较强的A15和A17能够维持较高的SOD、CAT、POD等抗氧化酶的活性,保持AsA-GSH循环系统中较高的AsA和GSH含量以及APX、GR等酶的活性,ROS、MDA产生较少,相对电导率升高幅度较小,叶绿体结构较完整,维持较高的叶绿体色素含量;而耐盐性较弱的1103P体内产生大量的ROS和MDA,叶绿体膜结构的完整性遭到破坏,叶绿素含量下降幅度大。