荞麦种子萌发期多种抗氧化酶活性的研究

通过研究荞麦种子萌发期(0～7 d)超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(ASP)四种抗氧化酶的酶活性变化,以及对自由基等的清除效果,分析荞麦种子内在抗氧化酶系统在萌发期对细胞膜结构的修复及保护作用。实验结果表明:荞麦种子在萌发期产生的活性氧、自由基等对四种抗氧化酶均有激活效应,其中超氧化物歧化酶(SOD)活性最先上升,其他三种酶随其后被激活,四种酶的氧化反应存在一定关联性和协同作用。苦荞的抗氧化酶活性高于甜荞。     

荞麦与大豆叶片中草酸含量差异及其可能的原因

用1/5浓度Hoagland营养液培养荞麦和大豆幼苗l0 d后,荞麦叶片、根及其分泌物中的草酸含量均明显高于大豆,说明荞麦叶片的草酸形成能力强.荞麦叶片中存在少量的草酸氧化酶活性,而大豆中未检测到该酶活性,表明荞麦具有一定的降解草酸的能力.乙醇酸氧化酶(GO)催化乙醇酸氧化的活性两种植物之间虽差异不明显,但该酶催化乙醛酸氧化的活性荞麦显著高于大豆.荞麦GO对乙醛酸的Km值明显低于大豆GO,同时其乙醛酸含量也较高,因此其叶片中由乙醛酸形成草酸的速率应高于大豆.由此认为,由乙醛酸氧化生成草酸可能是植物草酸合成限速步骤之一,其反应速率高低可能导致不同种类植物叶片中草酸含量的差异.     

边缘细胞对荞麦根尖铝毒的防护效应和对细胞壁多糖的影响

以2个荞麦(Fygopyrum esculentum Moench)基因型‘江西荞麦’(耐性)和‘内蒙荞麦’(敏感)为材料,采用悬空培养(保持边缘细胞附着于根尖和去除根尖边缘细胞),研究边缘细胞对根尖铝毒的防护效应以及对细胞壁多糖组分的影响。结果表明,铝毒抑制荞麦根系伸长,导致根尖Al积累。去除边缘细胞的根伸长抑制率和根尖Al含量高于保留边缘细胞的根。去除边缘细胞使江西荞麦和内蒙荞麦根尖的酸性磷酸酶(APA)活性显著升高,前者在铝毒下增幅更大。同时,铝毒胁迫下去除边缘细胞的根尖果胶甲酯酶(PME)活性和细胞壁果胶、半纤维素1、半纤维素2含量显著高于保留边缘细胞的酶活性和细胞壁多糖含量。表明边缘细胞对荞麦根尖的防护效应,与其阻止Al的吸收,降低根尖细胞壁多糖含量及提高酸性磷酸酶活性有关,以此缓解Al对根伸长的抑制。     

不同发酵茶中优势真菌的抗氧化酶活性

目的在云南普洱茶、广州小青柑、广西六堡茶、湖南熙茯茶及陕西泾阳茯砖茶分离到9种真菌的基础上,探讨9种真菌发酵液和发酵茶沸水冲泡液的抗氧化酶活性。方法采用抗氧化试剂盒测定真菌发酵液及发酵茶沸水冲泡液的抗氧化酶活性;利用Past 3软件对9种真菌发酵液抗氧化酶活性和5种发酵茶沸水冲泡液的抗氧化酶活性进行主成分分析。结果通过比较不同真菌发酵液的抗氧化酶活性表明,小青柑中分离到阿曲霉Q1的CAT(过氧化氢酶)活性最高,酶活力单位为(4.37±0.15)U/mL,熙茯茶中分离到谢瓦曲霉X1的POD(过氧化物酶)活性最高,酶活力单位为(21.67±1.05)U/mL,其次为泾茯茶中分离到赤散囊菌J17,酶活力单位为(18.59±2.74)U/mL;六堡茶中分离到的黑曲霉L1的T-SOD(总超氧化物歧化酶)的活性最高,酶活力单位为(71.11±3.90)U/mL,其次为普洱茶中分离到篮状菌P1,酶活力单位为(59.29±1.42)U/mL;通过比较不同发酵茶沸水冲泡液的抗氧化酶活性表明,5种发酵茶的CAT(F=37.409,P0.01),POD(F=164.268,P0.01),T-SOD(F=26.639,P0.01)活性差异均有统计学意义。其中,泾茯茶冲泡液的CAT活性最高,而其余4种茶叶冲泡液均无CAT活性;普洱茶与泾茯茶冲泡液的POD活性最高,酶活力单位分别为(18.11±0.71)和(18.11±0.64)U/mL;普洱茶和六堡茶冲泡液的T-SOD活性最高,酶活力单位分别为(48.72±0.43)和(45.82±2.02)U/mL;通过对9种真菌发酵液抗氧化酶活性的PCA分析表明,谢瓦曲霉X1、赤散囊菌J17、阿曲霉Q1、烟曲霉Q2、绳状篮状菌Q3和冠突曲霉L2的抗氧化酶活性相近,篮状菌P1、篮状菌P2和黑曲霉L1的抗氧化酶活性相近;通过对5种发酵茶沸水冲泡液抗氧化酶活性的PCA分析表明,小青柑与熙茯茶沸水冲泡后的抗氧化酶活性相近,六堡茶、普洱茶和泾茯茶沸水冲泡后的抗氧化酶活性相近。结论不同发酵茶的优势真菌不同,其真菌发酵产物的抗氧化酶活性不同,且不同发酵茶冲泡液的抗氧化酶活性也不同。     

灰树花孔菌固体发酵基质抗氧化活性成分研究

选用燕麦、大豆、玉米、麸皮、大米、荞麦6种培养基质对灰树花孔菌进行固体发酵及抗氧化活性研究。结果表明：灰树花孔菌最佳抗氧化发酵基质为燕麦大豆培养基（燕麦16.25%,大豆83.75%）,最佳发酵时间为8d。灰树花孔菌燕麦大豆发酵基质抗氧化活性成分种类丰富,含量高。其中总黄酮物质40.86μg/g,总三萜5.94mg/g,多酚8.51mg/g,还原糖13.10mg/g,花色苷70.23μg/g,维生素C 24.57mg/g,维生素E 0.33mg/g,谷光甘肽（GSH）0.84g/g,SOD酶活性299.74U/g。     

AM 真菌影响三叶草根系抗氧化酶活性的系统效应

本文对三叶草接种AM 真菌根内球囊霉, 用盆栽试验和分根试验测定根系的菌根侵染率和抗氧化酶活性, 研究AM 真菌对根系抗氧化酶活性的影响以及该影响的系统性。结果表明, 盆栽试验中接种根内球囊霉显著提高了根系中SOD、POD、CAT 的活性, 表明AM 真菌可以促进根系的抗氧化酶活性; 分根试验中一半根系接种了根内球囊霉的植株, 其另一半未接种的根系SOD、POD 活性也增加, 表明AM 真菌对根系抗氧化酶系统的促进具有系统效应。由于抗氧化酶系统是植物产生抗逆性的生理生化基础, 可以推测, AM 真菌对根系抗氧化酶活性的系统性提高有助于保护根系整体, 而非仅仅保护受侵染根段。     

荞麦黄酮及其生物合成调控研究进展

荞麦属植物资源丰富,且富含黄酮类成分。通过文献查阅,总结了荞麦黄酮历年研究情况以及热点研究领域。荞麦黄酮研究论文最早发表于1952年,在1952—1999近五十年的时间内,荞麦黄酮的研究论文较少,年发文量少于10篇,荞麦黄酮的研究处于起步阶段。自2000年后,荞麦黄酮逐渐获得更多研究学者的关注,年度发文量逐年上升。近年来,荞麦黄酮研究热点集中在植物学、食品科学技术、农学以及生物化学与分子生物学学科领域中,黄酮抗氧化活性相关的研究论文被引用次数较高,荞麦黄酮的生物活性与营养功能一直备受关注。目前,从荞麦中已经鉴定的黄酮类化合物达80种。槲皮素、山奈酚、木犀草素、鼠李素、异鼠李素、小麦黄素、柚皮素、杨梅素、芹菜素以及橙皮素是荞麦中常见的黄酮苷元结构,芍药色素、花翠素、矢车菊素为荞麦中多见的花青素类型。荞麦黄酮生物合成起源于苯丙烷代谢途径,PAL、CHS、C4H、4CL、CHI、LAR等黄酮合成途径中的多个关键酶基因以及MYB转录因子基因已被克隆鉴定。荞麦MYB转录因子在黄酮生物合成中发挥着重要的诱导调控作用,影响荞麦黄酮合成积累的因素主要有环境因素、植物生长调节剂、生物因素以及品种等,多个因素可相互交叉调控和影响荞麦黄酮的合成。该文通过回顾历年荞麦黄酮研究概况,总结黄酮化合物的种类,归纳黄酮生物合成途径调控机制及主要影响因素,为优质荞麦种植生产和优化提升荞麦产品的营养保健功能奠定理论基础和提供可行方案,为荞麦黄酮的深入研究指明方向。     

低温下钙对黄瓜幼苗抗氧化酶活性及POD同工酶谱的影响

以耐冷性存在明显差异的栽培黄瓜‘长春密刺’和‘北京截头’为材料,研究了冷胁迫下C a2 、钙离子螯合剂(EGTA)和钙调素拮抗剂(CPZ)对低温胁迫黄瓜幼苗叶片3种抗氧化酶活性及POD同工酶的影响.对保护酶活性的研究结果表明:C aC l2、EGTA和CPZ处理均能引起3种抗氧化酶活性变化,但变化幅度因材料而异.胁迫处理中C a2 能提高2种材料的叶片抗氧化酶活性,减少其在低温逆境中的下降幅度,而EGTA和CPZ处理降低了2种材料的抗氧化酶活性,加大了低温逆境中的下降幅度.POD同工酶研究发现,C aC l2延缓冷胁迫中同工酶条带的丢失,EGTA和CPZ处理则使同工酶条带丢失提前,但材料不同对酶条带丢失时间也有影响.     

不同氮素形态培养下荞麦叶片中草酸积累的变化

用1/5浓度Hoagland(pH6.0)营养液培养荞麦幼苗3d后,取其中一部分继续用此营养液(硝态氮);另一部分用硫酸氨和氯化钙取代硝态氮(氨态氮)的营养液,均培养至荞麦第一片真叶完全展开。结果表明,以氨态氮为唯一氮源培养荞麦时,植株叶片中草酸含量显著下降。进一步研究表明,氨态氮培养下荞麦根中及根分泌草酸的速率也显著下降,结果排除了叶片中草酸含量的下降是由于叶片中草酸向其根系转运或是因为根分泌草酸速率的差异造成的,而可能与其草酸代谢改变有关。氨态氮培养下叶片中与草酸代谢相关的有机酸含量以及相关酶活性也显著下降,这可能意味着荞麦叶片草酸形成积累可能与相关有机酸代谢有关。     

PFOS对再生东亚三角涡虫抗氧化酶活性的影响

为了探究全氟辛烷磺酸(Perfluorooctane sulfonate,PFOS)对再生涡虫抗氧化酶活性的影响,以再生中的涡虫作为实验材料,采用酶活性的测定的方法来探究PFOS对再生中东亚三角涡虫中抗氧化酶活性的影响。结果表明,PFOS刺激涡虫产生应激反应。在再生早期,PFOS胁迫会造成涡虫的氧化损伤和脂质的过氧化,并表现出随着PFOS浓度的升高,涡虫氧化损伤程度加剧的趋势;再生5 d时,机体产生抗氧化的反应来消除体内的氧自由基;在再生的后期,由于涡虫对药物的耐受作用,涡虫的抗氧化反应不显著。     

Cu~(2+)、Pb~(2+)和Cd~(2+)对荞麦种子中抗氧化酶活性的影响

近年来,有关荞麦降血脂、降血糖和抗衰老等的作用引起国内外生化、营养和医药学界的普遍关注[1,2].一些研究表明,荞麦中富含超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)等能够清除机体内超氧阴离子自由基(O-·2)、羟自由基(·OH)和H2O2等有害物质?..     

In situ and in vitro senescence induced by KCl stress: nutritional imbalance, lipid peroxidation and antioxidant metabolism

Sunflower (Helianthus annuus L. cv. SH222) plants and calli were exposed to KCl stress for three weeks. Calli were more tolerant to KCl than plants. KCl stress decreased NO(-)(3), Mn, Fe and B levels in whole plants and P, Ca and Mg in shoots. NO(-)(3), P, Ca, Mg, Mn, and B levels decreased in 100 mM-stressed calli. Chlorophyll content, F:(m) and (F:(m)-F:(0))/F:(m) ratio decreased in stressed leaves, while F:(0) increased only in leaves exposed to severe stress (100 and 150 mM). Membrane permeability and lipid peroxidation increased in plants under all stress conditions and in 100 and 150 mM stressed calli, but remained unchanged in 25 mM stressed calli. Salt stress also induced changes relating to antioxidant enzymes: plants under all stress conditions showed a decrease in catalase, peroxidase and SOD activities. Calli under moderate stress (25 mM KCl) showed an increase of catalase, peroxidase and SOD activities, but the activities of peroxidase and SOD decreased when calli were exposed to higher KCl concentrations. The decrease of antioxidant enzyme activities is in tune with lipid peroxidation and membrane permeability increases. On the other hand, calli adapted for 6 months to 100 mM KCl showed an increase of these enzyme activities compared to unstressed calli, while MDA production and membrane permeability were not significantly affected.     

Different effects of exercise tests on the antioxidant enzyme activities in lymphocytes and neutrophils

We have determined the effects of maximal and submaximal cycloergometer tests on the antioxidant enzyme defences of neutrophils and lymphocytes. We also compared the neutrophil and lymphocyte basal enzyme antioxidant activities. A total of 17 well-trained amateur athletes, runners, and cyclists participated in this study. Two tests were performed on an electromagnetic reduction cycloergometer: the maximal exercise test, and the submaximal prolonged exercise test. Blood samples were taken before and after the tests. Basal enzyme activity of superoxide dismutase was higher in lymphocytes but neutrophils presented higher activities of catalase and glutathione peroxidase. The maximal test increased the circulating number of lymphocytes and the activities of catalase and glutathione peroxidase. No changes were observed in lymphocyte number or in lymphocyte antioxidant enzyme activities after the submaximal test. The circulating number of neutrophils increased significantly after the submaximal test. Maximal and submaximal tests decreased the activities of neutrophil glutathione dependent antioxidant enzymes (glutathione peroxidase and glutathione reductase), but no changes were observed in catalase or superoxide dismutase activities after either test. Neither the maximal nor submaximal test produced increases in serum activities of lactate dehydrogenase and creatine kinase (CK).     

Interspecific diversity in root antioxidative enzyme activities reflect root turnover strategies and preferred habitats in wetland graminoids

Antioxidant enzymes protect cells against oxidative stress and are associated with stress tolerance and longevity. In animals, variation in their activities has been shown to relate to species ecology, but in plants, comparative studies with wild species are rare. We investigated activities of five antioxidant enzymes – ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), peroxidase (POX), and superoxide dismutase (SOD) – in roots of four perennial graminoid wetland species over a growing season to find out whether differences in root turnover or habitat preferences would be associated with variation in seasonal patterns of antioxidant enzyme activities. The investigated species differ in their root turnover strategies (fine roots senesce in the fall or fine roots survive the winter) and habitat preferences (nutrient‐poor vs. productive wetlands). Roots were collected both in the field and from garden‐grown plants. Antioxidant enzyme activities were higher and lipid peroxidation rates lower in species with annual root systems, and for species of the nutrient‐poor wetland, compared with perennial roots and species of productive wetlands, respectively. There was variation in the activities of individual antioxidant enzymes, but discriminant analyses with all enzymes revealed a clear picture, indicating consistent associations of antioxidant enzyme activities with the type of root turnover strategy and with the preferred habitat. We conclude that antioxidant enzyme activities in plant roots are associated with the species' ecological strategies and can be used as traits for the characterization of the species' position along plant economics spectrum.     

Induction of Male Sterility in Wheat by Meiotic-Stage Water Deficit Is Preceded by a Decline in Invertase Activity and Changes in Carbohydrate Metabolism in Anthers

Total peroxidase, NADH-peroxidase, ascorbate peroxidase, superoxide dismutase, and catalase activities were measured in tobacco (Nicotiana tabacum) leaves and in regenerating and nonregenerating protoplasts isolated from the same tissue and cultured for 2 weeks. The specific ranges of H2O2 concentration at which the enzymes scavenging the active forms of oxygen may efficiently operate and the activities of those enzymes were determined in an extract from tobacco leaves and in dividing and nondividing tobacco mesophyll protoplasts. The overall H2O2-scavenging enzyme activities were similar in both protoplast populations during the 2 to 3 d of culture. After 3 d, the regenerating protoplasts started to divide and both the antioxidant enzyme activities and the total peroxidase activity increased; in contrast, the viability and the H2O2-scavenging enzyme activities in nonregenerating protoplasts dramatically decreased. Surprisingly, the regenerative potentiality in dividing protoplasts was specifically correlated with a higher NADH-peroxidase activity, which resulted in a net H2O2 accumulation in the cells. Light, which causes the accumulation of active forms of oxygen in photosynthetic organelles, also stimulated catalase and ascorbate peroxidase activities in dividing protoplasts. We suggest that the localization of H2O2 rather than its absolute concentration might be responsible for oxidative stress and that controlled amounts of H2O2 are necessary to allow proper cell-wall reconstitution and the consequent cell division.     

The activities of antioxidant enzymes in response to oxidative stresses and hormones in paraquat-tolerant Rehmannia glutinosa plants

All members of R. glutinosa show the unique characteristic of intrinsic tolerance to paraquat (PQ). Antioxidant enzymes have been proposed to be the primary mechanism of PQ resistance in several plant species. Therefore, the antioxidant enzyme systems of R. glutinosa were evaluated by comparatively analyzing cellular antioxidant enzyme levels, and their responses of oxidative stresses and hormones. The levels of ascorbate peroxidase (APX), glutathione reductase (GR), non-specific peroxidase (POX), and superoxide dismutase (SOD) were 7.3-, 4.9-, 2.7- and 1.6-fold higher in PQ-tolerant R. glutinosa than in PQ-susceptible soybeans. However, the activity of catalase (CAT) was about 12-fold higher in the soybeans. The activities of antioxidant enzymes reduced after PQ treatment in the two species, with the exception of POX and SOD in R. glutinosa, which increased by about 40 %. Interestingly, the activities of APX, SOD and POX in R. glutinosa, relative to those in soybeans, were further increased by 49, 67 and 93 % after PQ treatment. The considerably higher intrinsic levels, and increases in the relative activities of antioxidant enzymes in R. glutinosa under oxidative stress support the possible role of these enzymes in the PQ tolerance of R. glutinosa. However, the relatively lower levels of SOD versus PQ tolerance, and the mixed responses of antioxidant enzymes to stresses and hormones, suggest a possible alternative mechanism(s) for PQ tolerance in R. glutinosa.     

Physiological responses to drought and shade in two contrasting Picea asperata populations

The responses of photosynthetic gas exchange, chlorophyll fluorescence, activities of antioxidant enzymes and lipid membrane peroxidation of two contrasting Picea asperata Mast. populations to 30% of full sunlight (shade) and full sunlight (sun) were investigated under well-watered and drought conditions. Two contrasting populations were from the wet and dry climate regions in China, respectively. For both populations tested, drought resulted in lower needle relative water content (RWC), CO₂ assimilation rate ( A ), stomatal conductance ( gs ) and effective PSII quantum yield ( Y ), and higher non-photochemical quenching ( qN ), superoxide dismutase (SOD), ascorbate peroxidase (APX) activities as well as malondialdehyde (MDA) levels and electrolyte leakage in sun plants, whereas these changes were not significant in shade plants. For the wet climate population, shade plants showed higher chlorophyll contents (Chl a , Chl b and Chl a + b ) than sun plants under both well-watered and drought conditions. Our study results implied that shade, applied together with drought, ameliorated the detrimental effects of drought. On the other hand, compared with the wet climate population, the dry climate population was more tolerant to drought in the sun treatment, as indicated by less decreases in A and mass-based leaf nitrogen content ( N _mass), more responsive stomata, greater capacity for non-radiative dissipation of excitation energy as heat (analysed by qN ), and higher level of antioxidant enzyme activities as well as lower MDA content and electrolyte leakage. These results demonstrated that the different physiological strategies were employed by the P. asperata populations from contrasting climate regions when the plants were exposed to drought and shade.     

西花蓟马取食与机械损伤对菜豆叶片抗氧化系统的影响

本文研究了西花蓟马Frankliniella occidentalis(Pergande)取食和机械损伤诱导对菜豆抗氧化系统的影响,比较了不同损伤形式诱导的抗氧化酶活力和抗氧化物质含量的变化差异。结果表明,西花蓟马取食和机械损伤均可诱导菜豆叶片内过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)3种抗氧化酶活性有不同程度的升高,但两种处理诱导的抗氧化酶活性变化规律不完全相同,各种酶活性达到最高点时间不同,西花蓟马取食对抗氧化酶活力的诱导作用大于机械损伤的。两种处理诱导下的类胡萝卜素的含量变化不大,但不论西花蓟马取食还是机械损伤均导致菜豆叶片内类黄酮和总酚含量整体呈下降趋势,西花蓟马的取食诱导的下降幅度大于机械损伤的。因此,西花蓟马取食诱导明显高于机械损伤对菜豆抗氧化系统的影响。     

Species variation in lung antioxidant enzyme activities

Exposure of several different animal models to O2-induced lung injury has revealed marked differences in sensitivity of various species to O2 damage. These differences may be due in part to variation of cellular antioxidant defenses. To characterize lung antioxidant enzyme activities in different species, we measured lung activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GSH S-trans) in rat, hamster, baboon, and human lung. Soluble lung fractions were also fractionated on Sephadex G-150-S columns and GSH-Px activity was measured using both cumene hydroperoxide and H2O2. This was done to evaluate non-Se-dependent GSH-Px activity in these lung samples. Human lung was obtained at surgery from patients undergoing lobectomy or pneumonectomy for localized lung tumors. SOD activity was similar for all four groups. GSH-Px activity was higher in rat lung than baboon or hamster lung. Lung CAT activity was variable with the highest activity present in the baboon which revealed a lung CAT activity 10 times higher than activity present in the rat. Lung GSH S-trans activities were higher in hamster, baboon, and human lung than in rat lung. Non-Se-dependent GSH-Px was present in rat lung but absent in hamster, baboon, and human lung. We conclude that the hamster was the best model of the animals studied for mimicking human lung antioxidant enzyme activities. Rat lung antioxidant enzyme activities were markedly different from any of the other species examined.