Mitochondrial lipid peroxidation is influenced by dietary factors in early colon carcinogenesis

Oxidative damage to mitochondrial proteins, lipids, and DNA seem to influence the promotion and progression of tumors. High-fat diets and diets high in iron decrease manganese superoxide dismutase activity, a mitochondrial antioxidant, in colon mucosa. Lipid peroxidation products are low in microsomal preparations from colonic mucosa even under peroxide-inducing conditions. However, damage specific to mitochondrial membranes is unknown. This study was designed to investigate dietary lipid and iron effects on fatty acid incorporation and lipid peroxide formation in mitochondrial membranes of colonic mucosa. Male Fischer rats were fed high-fat diets containing either corn oil or menhaden oil with an iron level of either 35 or 535 mg/kg diet. Animals were given two injections of the colon carcinogen, azoxymethane, or saline. Colon tissue was collected 1 and 6 weeks after injections. Mitochondrial and microsomal fractions were prepared for fatty acid analysis and quantitation of lipid peroxidation products. Results showed that lipid composition of both subcellular fractions were influenced by diet. Fatty acid composition of mitochondria differed from microsomes, but overall saturation remained constant. Peroxidation products in mitochondrial membranes were significantly greater than in microsomal membranes. Dietary treatment significantly affected mitochondrial peroxidation in carcinogen-treated animals. Therefore, mitochondria from colon mucosa are more susceptible to peroxidation than are microsomes, dietary factors influence the degree of peroxidation, and the resulting damage may be important in early colon carcinogenesis.     

Effect of laser pretreatment on germination and membrane lipid peroxidation of Chinese pine seeds under drought stress

The germination of laser-irradiated Chinese pine seeds was carried out under drought stress. The activities of superoxide dismutase (SOD) and peroxidase (POD), and the content of malondialdehyde (MDA) were determined. Results showed notably increased germination percentage, root length, vitality index and fresh weight. The SOD and POD protective enzyme system activity of the Chinese pine seedlings obviously rose. It can be concluded that the germination and juvenile resistance of Chinese pine seeds under drought stress are enhanced after laser processing. Translated from Journal of Shaanxi Normal University (Natural Science Edition), 2006, 34(2): 40–43 [译自: 陕西师范大学学报 (自然科学版)]     

Effect of laser pretreatment on germination and membrane lipid peroxidation of Chinese pine seeds under drought stress

The germination of laser-irradiated Chinese pine seeds was carried out under drought stress.The activities of superoxide dismutase (SOD) and peroxidase (POD),and the content of malondialdehyde (MDA) were determined.Results showed notably increased germination percentage,root length,vitality index and fresh weight.The SOD and POD protective enzyme system activity of the Chinese pine seedlings obviously rose.It can be concluded that the germination and juvenile resistance of Chinese pine seeds under drought stress are enhanced after laser processing.     

Gene expression and activity of antioxidant enzymes in barley (Hordeum vulgare L.) under controlled severe drought

The objective of the present study was to determine the activity of antioxidant enzymes: superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) and the expression of their genes in two barley genotypes under controlled severe drought. To fulfill this objective, 21-day-old barley plants of two genotypes: Rum and Yarmouk were exposed to controlled severe drought (25% field capacity) for 2, 9, and 16 days. The activity of SOD was significantly high in Rum genotype after 2 days of drought treatment. In Yarmouk genotype, the activity of APX was significantly high after 2 and 9 days of drought treatment. In Rum genotype, CAT2 was upregulated after 9 days of drought treatment and SOD and APX were upregulated after 16 days of drought treatment, whereas CAT2, SOD, and APX were upregulated in Yarmouk genotype after 2 days of drought treatment. The results indicate a unique pattern of activity and gene expression of the antioxidant enzymes in the two barley genotypes under controlled severe drought. Moreover, the data suggest that each genotype utilizes different molecular and biochemical responses under the same drought conditions.     

Influence of silicon on antioxidant mechanisms and lipid peroxidation in chickpea (Cicer arietinum L.) cultivars under drought stress

Abstract

The effects of exogenous silicon (Si) on leaf relative water content (RWC), and the growth, Si concentrations, lipid peroxidation (MDA), lipoxygenase (LOX) activity, proline and H₂O₂ accumulation, non-enzymatic antioxidant activity (AA) and the activity of some antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX) in shoots of ten chickpea cultivars grown under drought were investigated. Drought stress decreased the growth of all the cultivars while applied Si improved the growth at least five of the 10 chickpea cultivars. Silicon applied to the soil at 100 mg kg^?1 significantly increased Si concentrations of the cultivars and counteracted the deleterious effects of drought in 5 of the ten chickpea cultivars by increasing their RWC. In most cultivars tested H₂O₂, proline and MDA content and LOX activity were increased by drought whereas application of Si decreased their levels. APX activity was increased by drought but it was depressed by Si. In general, SOD and CAT activities of the cultivars were decreased by drought. Depending on cultivars, the CAT activity was decreased, and increased or unchanged in response to applied Si, while the SOD activity of the cultivars increased or unchanged by Si. The non-enzymatic antioxidant activity of the cultivars was also increased by Si. These observations implied an essential role for Si in minimizing drought stress-induced limitation of the growth and oxidative membrane damage in chickpea plants.     

信号分子水杨酸减缓干旱胁迫对紫御谷光合和膜脂过氧化的副效应

为研究信号分子水杨酸(SA)对干旱胁迫下紫御谷光合和膜脂过氧化的影响,为SA应用于紫御谷抗旱育苗提供理论依据,测定分析了SA处理对干旱胁迫下紫御谷幼苗叶片光合和膜脂过氧化相关指标的变化。结果表明:(1)干旱胁迫破坏了紫御谷叶绿体的膜结构,使基粒数量明显减少,垛叠不明显,排列比较松散,而SA处理能在一定程度上保护叶绿体的膜结构。(2)干旱胁迫降低了紫御谷幼苗叶片的叶绿素b和总叶绿素含量,而SA处理能提高干旱胁迫下紫御谷幼苗叶片的叶绿素a、叶绿素b、总叶绿素和胡萝卜素含量。(3)干旱胁迫降低了叶片的净光合速率、气孔导度、蒸腾速率、光饱和点和暗呼吸速率,增加了叶片的光补偿点、CO₂饱和点、CO₂补偿点和光呼吸速率,而SA处理则增加了紫御谷幼苗叶片的净光合速率、气孔导度、光饱和点和暗呼吸速率,降低了紫御谷幼苗叶片的光补偿点、CO₂饱和点、CO₂补偿点和光呼吸速率。(4)干旱胁迫降低了紫御谷幼苗叶片的F_v/F_m和Φ_PSⅡ,显著增加了叶片的相对电导率和丙二醛含量,而SA处理则增加了幼苗叶片的F_v/F_m和Φ_PSⅡ,降低了叶片的相对电导率和丙二醛含量。表明:信号分子水杨酸能够有效减缓干旱胁迫对紫御谷光合和膜脂过氧化的影响。     

病原真菌中潜在的铁死亡通路：功能与研究展望

铁死亡是一种铁离子参与、使细胞内脂质过氧化物积累到致死水平的新型程序性细胞死亡形式。目前,铁死亡的作用与机制在动物细胞已广泛、深入研究,而真菌铁死亡研究才刚刚起步。本综述旨在探讨铁离子稳态调控因子、膜脂抗氧化系统及脂质过氧化酶促系统这3种已知的铁死亡调控途径,列举它们在真菌中的同源蛋白的生物学功能。我们推测,病原真菌细胞铁死亡也许广泛参与其生长发育和致病性方面的调控,铁死亡调控通路有可能成为真菌病害防控的新的潜在靶标。     

CO2浓度倍增对干旱胁迫下黄瓜幼苗膜脂过氧化及抗氧化系统的影响

为了探明CO2浓度倍增对干旱胁迫下黄瓜幼苗氧化损伤的缓解机理,为未来大气CO2浓度升高或温室CO2施肥以及干旱、半干旱地区水分亏缺等逆境胁迫下黄瓜的优质高效栽培提供理论依据和技术参数,以温室专用黄瓜品种津优1号(Cucumissativus L.var.Jinyou No.1)为试材,采用裂区设计,主区因素为CO2浓度处理,设2个CO2浓度水平:大气CO2浓度(≈380μmol/mol,表示为Ambient[CO2])和倍增CO2浓度((760±20)μmol/mol,表示为Doubled[CO2]);裂区因素为水分处理,用PEG6000模拟根际干旱胁迫,设3个水分处理水平:对照(营养液,表示为C)、中度干旱胁迫(含5%PEG6000的营养液,相当于水势ψw=-0.05MPa,表示为M)和重度干旱胁迫(含10%PEG6000的营养液,相当于水势ψw=-0.15MPa,表示为S),研究了CO2浓度倍增对干旱胁迫条件下黄瓜幼苗叶片渗透调节物质含量、膜脂过氧化及抗氧化系统的影响,结果表明:(1)干旱胁迫导致黄瓜幼苗活性氧积累,质膜透性增大,丙二醛含量升高,同时幼苗叶片脯氨酸、可溶性蛋白质和可溶性总糖含量显著增加,抗氧化酶活性(SOD、POD、CAT、APX和GR)显著提高,抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量显著升高;(2)CO2浓度倍增不仅有利于促进干旱胁迫条件下黄瓜叶片渗透调节物质的积累,而且能够促进干旱胁迫条件下黄瓜叶片抗氧化酶(SOD、POD、CAT、APX和GR)活性的表达,减轻干旱胁迫下活性氧的积累,使膜脂过氧化程度下降,质膜相对透性降低,丙二醛含量减少,对防止植物的氧化损伤具有一定的保护作用。综上所述,推测温室CO2施肥或未来CO2浓度升高可在一定程度上增强黄瓜幼苗的抗旱性和缓解干旱胁迫的负效应。     

藜对干旱胁迫的生理生化反应

干旱是植物最易遭受的胁迫之一,每年由于干旱胁迫给农业造成损失几乎相当于其他所有环境因子胁迫所造成的损失的总和。通过人工控制水分模拟干旱来研究生长期的藜对干旱胁迫的生理生化反应,以期望为干旱农业的高效生产提供理论依据。以盆栽的藜为材料,用控制浇水的方法分对照、轻度胁迫、中度胁迫、重度胁迫4个组,研究了不同程度干旱胁迫对藜叶片的水分状况、渗透调节物质、活性氧代谢以及内生保护系统的影响。结果表明:在干旱胁迫下,藜叶片相对含水量(RW C)、自由水含量(FW C)下降,束缚水含量(BW C)上升;可溶性糖、脯氨酸、K 、C a2 含量增加,表现出藜对适度干旱有一定的适应性。但重度干旱胁迫,O2.产生速率和丙二醛(M DA)含量显著提高,导致膜损伤,质膜透性上升;超氧化物歧化酶(SOD)、过氧化物酶(POD)活性先上升,后下降;抗坏血酸(A SA)含量降低。过分干旱胁迫对藜会造成一定伤害。     

酸枣保护酶活性和膜脂过氧化产物对干旱胁迫的响应

以3年生酸枣为试材,通过盆栽控水试验法研究干旱胁迫条件下酸枣生理生化特性的响应规律。结果表明:随着干旱胁迫梯度的加大、干旱时间的延长,保护酶SOD、POD和CAT在酸枣体内积累,表现出先增后降的变化趋势;在中度干旱下SOD活性达到608.36 U/g·FW,高于CK组52.14%且差异极显著(P0.01),POD活性达到190.97μg/min·g·FW,高于CK组113.59%(P0.01)。而CAT活性变化与SOD、POD略有不同,随胁迫程度的加重,其活性逐渐降低,仅高于CK组1.40倍(P0.05)。电导率、NR活性以及丙二醛(MDA)含量表现出增加的趋势;电导率持续升高,高于CK组11.14倍(P0.01),对膜的结构和功能破坏越严重。NR活性达到14.60μg/(g·h)比CK增加了94.66%(P0.01),MDA含量达到26.82μmoL/g·FW,是CK组的2.71倍(P0.05),膜脂过氧化反应加强,对膜的伤害增加。     

Effects of potato and lotus leaf extract intake on body composition and blood lipid concentration

[Purpose]

The purpose of this study was to investigate the effects of potato and lotus leaf extract intake on body composition, abdominal fat, and blood lipid concentration in female university students.

[Methods]

A total of 19 female university students participated in this 8-week study, and they were randomly assigned into 2 groups; potato and lotus leaf extract (skinny-line) administered group (SKG, n =9) and placebo group (PG, n = 10). The main results of the present study are presented below.

[Results]

1) Body mass index, and percent body fat and abdominal fat in students of the SKG showed a decreasing tendency without significant interaction, 2) total cholesterol (TC), triglyceride (TG), and low density lipoprotein (LDL-C) in students of the SKG showed an averagely decreasing tendency and there was a significant interaction of TC only, 3) high density lipoprotein (HDL-C) in students of the SKG showed an increasing tendency without significant interaction, and 4) Z-score of fatness testing interaction in group × repetition did not show a significant interaction; however, there was a significant interaction of TC in group × repetition. Based on these results, 8-week intake of potato and lotus leaf extract had a positive effect of lowering TC. On the other hand, it had no significant effect on other types of lipids and percent body fat changes.

[Conclusion]

There was a positive tendency of blood lipids in students of the SKG and it seems that potato and lotus leaf extract intake might prevent obesity and improve obesity related syndromes.     

外源一氧化氮供体硝普钠对干旱胁迫下小麦幼苗叶中ATP酶活性和膜脂过氧化的影响

研究外源一氧化氮（NO）供体硝普钠（sNP）对干旱胁迫下小麦幼苗叶片ATP酶活性和膜脂过氧化影响的结果表明,15％聚乙二醇．6000（PEG-6000）模拟的干旱胁迫下小麦幼苗叶中H^＋-ATP酶和Ca^2＋．ATP酶活性显著升高后迅速下降,硫代巴比妥酸反应产物（TBARs）和质量膜透性增加;0．1mm01．L^-1 SNP可提高干旱胁迫下小麦幼苗叶中超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（cAT）活性,降低超氧阴离子（O2^-）和过氧化氢（H2O2）水平,缓解膜脂过氧化,稳定生物膜的结构和功能,H^＋-ATP酶和Ca^2＋-ATP酶也可以保持更高的活性。     

干旱胁迫对坡柳等抗旱树种幼苗膜脂过氧化及保护酶活性的影响

以金沙江干热河谷主要树种坡柳、银合欢、山毛豆实生幼苗为材料,通过盆栽苗自然干旱胁迫,同时以浇水处理为对照,研究了干旱胁迫对坡柳、银合欢、山毛豆3个树种丙二醛含量、膜相对透性及保护酶活性的影响。结果表明,干旱胁迫下3个树种幼苗的细胞膜透性、MDA及SOD, POD酶活性都发生了变化,只是变化的幅度和进程不同。干旱胁迫对银合欢膜系统损伤生成的主要降解产物不是MDA;山毛豆清除活性氧毒害作用主要不是通过SOD和POD的作用;通过叶片相对保水力测定及膜透性、MDA相对含量、酶活性变化情况的分析,3个树种中坡柳耐旱性最强,其次为银合欢,山毛豆居后。