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101.
Ethyl 2-methyl acetoacetate (EMA) is a novel allelochemical exhibiting inhibitory effects on the growth of marine unicellular alga Phaeodactylum tricornutum (P. tricornutum). Oxidative damage and antioxidant responses in P. tricornutum were investigated to elucidate the mechanism involved in EMA inhibition on algal growth. The increase in reactive oxygen species (ROS) levels and malondialdehyde (MDA) contents following exposure to EMA suggested that alga was suffered from oxidative stress and severely damaged. The decrease in cell activity and cellular inclusions suggested that cell growth was greatly inhibited. The activities of the antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxide (GSH-PX) and glutathione S-transferase (GST) increased with the exposure concentration and decreased with the prolongation of exposure time. Cellular ascorbic acid (AsA) and reduced glutathione (GSH) systems were also involved in resisting oxidative stress of EMA by altering the composition of AsA and GSH pools. EMA exposure increased the contents of AsA, GSH, dehydroascorbate (DAsA) and glutathione (GSSG). However, the regeneration rate of AsA/DAsA did not change obviously between treatments and the control, while that of GSH/GSSG decreased significantly under 14 mmol/L EMA exposure on the 3rd day. These results showed that EMA-induced oxidative damage might be responsible for EMA inhibition on P. tricornutum growth and cellular antioxidant enzymes and non-enzymatic antioxidants were improved to counteract the oxidative stress.  相似文献   
102.
The study was undertaken to evaluate the effects of different concentrations of phoxim on acetylcholinesterase (AChE) and esterase (EST) activities, and antioxidant system after topical application to Oxya chinensis. The results showed that phoxim inhibited AChE activity, and did not cause significant changes in the EST activity and the levels of malondialdehyde (MDA) and reduced glutathione (GSH). After phoxim administration, superoxide (SOD) and catalase (CAT) activities showed a biphasic response with an initial increase followed by a decline in their activities. Glutathione reductase (GR) and glutathione peroxidase (GPx) activities were inhibited in comparison with the control. Glutathione S-transferase (GST) activity showed irregular changes. Its activity increased significantly at the concentrations of 0.06 and 0.12 μg/μL and decreased at the concentrations of 0.09 and 0.24 μg/μL compared with the control. Changes in SOD, CAT, GST, GPx, and GR activities indicated that phoxim caused oxidative damage in O. chinensis. However, no significant changes in MDA content suggested that these enzymes played important roles in scavenging the oxidative free radicals induced by phoxim in O. chinensis. The formation of oxygen free radicals might be a factor in the toxicity of phoxim.  相似文献   
103.
在泥鳅养殖水体中添加稻秆粉模拟水稻残遗物生境,研究了泥鳅生长和肝胰脏抗氧化酶(SOD、CAT)与解毒酶(GST)活性对转Cry1Ab/Ac基因水稻‘华恢1号’(HH1)的响应。设计以HH1稻秆粉10 mg·L?1、50 mg·L?1、100 mg·L?1和200 mg·L?1 4个梯度浓度处理泥鳅为试验组,以非转Bt基因水稻‘明恢63’(MH63)稻秆粉处理组为阴性对照,不加稻秆粉的基础饲养组为空白对照。结果显示:在4种稻秆粉浓度下,HH1组与MH63对照组泥鳅的特定生长率、肥满度、内脏系数及SOD、CAT和GST酶活性均无显著差异(P0.05);与空白对照比较,稻秆粉浓度升高对泥鳅生长的抑制逐渐增强,当浓度达到200 mg·L?1时,HH1组和MH63对照组泥鳅的特定生长率、内脏系数与CAT活性降低。研究结果表明,水体中低含量的转融合基因Cry1Ab/Ac水稻HH1稻秆粉对泥鳅的生长与生理酶活性没有明显影响,高浓度HH1和MH63稻秆粉均使泥鳅的生长和生理酶活性显著降低,这可能与养殖水体中浓度较高的悬浮稻秆粉妨碍了泥鳅的呼吸和滤食,及稻秆粉的分解降低了水体p H和溶氧量有关。  相似文献   
104.
为了探究改良剂与超富集植物联合修复锰(Mn)污染土壤,采用温室土培的方法,研究了Mn污染土壤分别添加25、50 g/kg的海泡石(S2.5,S5)和沸石(Z2.5,Z5)对Mn超富集植物短毛蓼(Polygonum pubescens Blume)生长、Mn吸收及叶片抗氧化酶系统的影响。结果表明:改良剂添加显著增加了短毛蓼茎、叶中Mn的含量(P0.05),但降低了株重、叶绿素a和叶绿素b含量。S2.5、Z5.0处理的株高比对照提高了15%和16%,Z2.5与Z5.0处理分别比对照降低了40.05%、35.58%。沸石和海泡石添加显著提高了短毛蓼叶片中MDA含量及H2O2含量(P0.05),表明短毛蓼受到了一定胁迫。超氧自由基(·O2–)含量在S2.5、S5.0、Z2.5处理时下降了4.69%、16.49%、21.01%。同时沸石和海泡石引起了短毛蓼抗氧化酶活性和非酶物质含量的改变。海泡石显著提高(P0.05)短毛蓼叶片中超氧歧化酶(SOD)活性,在S2.5、S5.0处理下,SOD活性分别比对照提高了14%和15%;POD、CAT活性也均有不同程度提高,在S2.5、S5.0处理下,POD分别是对照的4.63、4.23倍,Z2.5、Z5.0处理分别是对照的4.71、4.74倍;但显著降低了抗坏血酸过氧化物酶活性以及–SH、GSH含量(P0.05)。表明沸石和海泡石对短毛蓼抗氧化酶系统的影响不一。  相似文献   
105.
采用田间试验的方法,以全膜不覆土穴播种植方式为对照,比较研究全膜覆土穴播对旱地冬小麦旗叶光合、抗氧化酶活性和膜脂过氧化水平的影响。结果表明,全膜覆土穴播处理提高了冬小麦灌浆中后期(花后20~35d)旗叶净光合速率(Pn)和叶绿素SPAD值,Pn高值持续期(PAD)和叶绿素SPAD值缓降期(RSP)比对照分别增加6.5d和5.8d。全膜覆土穴播也提高了灌浆初期(花后0~15d)旗叶蔗糖磷酸合成酶(SPS)活性,与对照相比提前5d达到峰值,且在灌浆中期(花后10~20d)依然能保持相对较高的蔗糖供应能力。全膜覆土穴播在灌浆中后期(10~35d)超氧化物歧化酶(SOD)活性表现较强的诱导性,过氧化氢酶(CAT)活性也比对照提前5d达到峰值,而过氧化物酶(POD)活性始终低于对照。2种处理丙二醛(MDA)质量摩尔浓度在开花15d后急剧升高,但全膜覆土穴播处理的质量分数和变化幅度均低于对照。可见,全膜覆土穴播栽培的旱地冬小麦在灌浆期保持了较高的光合产物供应速率、较长的供应持续期、较低的活性氧产生速率和膜脂过氧化水平,因而后期产量和品质高于传统地膜栽培。  相似文献   
106.
[目的]研究壳寡糖的抗氧化性及壳寡糖对冷藏鲫鱼保鲜性能的影响.[方法]以壳寡糖为原料,采用邻二氮菲-Fe2氧化法、DP-PH法等对壳寡糖的抗氧化性进行了测定,以pH、TVB-N及TBA为指标研究了壳寡糖对鲫鱼保鲜性能的影响.[结果]研究表明,1.5mg/ml壳寡糖溶液的还原能力相当于50 μg/ml阳性对照VC的还原能力;1 mg/ml壳寡糖溶液对羟自由基的清除率为45%,相当于100μg/ml阳性对照VC对羟自由基的清除率;4 mg/ml的壳寡糖溶液对DPPH自由基的清除率达到97.8%.新鲜鲫鱼在4℃冰箱冷藏条件下,壳寡糖溶液涂膜处理组和对照组在第8天时的TVB-N值分别为252.0和196.0 mg/kg;pH分别为7.73和6.69;TBA值分别为1.552和0.670.综合各项指标的变化,壳寡糖涂膜保鲜的鲫鱼货架期明显比对照组长,表明壳寡糖具有较好的抗氧化能力和保鲜性能.[结论]研究可为壳寡糖在更多领域更广泛的开发应用奠定基础.  相似文献   
107.
采用正交试验法对商洛绿茶茶多酚的制备工艺进行了优化,并从DPPH自由基、羟基自由基、超氧阴离子、ABTS自由基和总还原力方面分别检测了商洛绿茶茶多酚的体外抗氧化活性。研究表明:商洛绿茶茶多酚的最佳提取工艺条件为液料比20∶1、浸提温度60℃、乙醇浓度50%、浸提时间30 min;商洛绿茶茶多酚具有较强的抗氧化活性,并且呈现出良好的量-效关系。  相似文献   
108.
Conventional chitosan (CC) and submicron chitosan dispersions (SCD) were evaluated for the control of postharvest anthracnose and maintenance of quality of dragon fruit during storage at 10 ± 2 °C and 80 ± 5% RH for 28 days. All the chitosan treatments significantly reduced anthracnose symptoms, resulting in a reduction of disease development and thereby maintained the quality of fresh fruit for extended periods. SCD at 1.0% with 600 nm droplet size gave the best result in that it delayed the onset of disease and maintained the quality of dragon fruit for up to 28 days of storage. It can be concluded from the present investigation that SCD have potential to be used as an antifungal agent to control postharvest anthracnose and maintain quality of dragon fruit during storage.  相似文献   
109.
The black leaf streak disease (BLSD), caused by Mycosphaerella fijiensis, is the most destructive disease of bananas and plantains around the world. Breeding for resistance is the most promising strategy to fight this disease especially in small farmer plantations. Mycosphaerella fijiensis produces many phytotoxins such as juglone, which can be used, jointly with field and inoculations under controlled conditions, for screening banana cultivars for BLSD-resistance. This non-host specific phytotoxin has been shown to act on chloroplasts and disturbs the proton electrochemical gradient across the plasmalemma membrane. Moreover, an involvement of the oxidative burst during the interaction has been suggested. The present study was carried out using two cultivars that differed for either their juglone-responses or their resistance to BLSD (cv. Grande Naine susceptible to BLSD and juglone and cv. Fougamou partially resistant to BLSD and highly tolerant to juglone). The production of active oxygen species (AOS) and the enhancement of the enzymatic and/or non-enzymatic AOS-scavenging systems were investigated after treatment of the two cultivars with juglone. The time-course of AOS-production and AOS-scavenging was shown to be the key difference between these two tested cultivars after treatment with juglone. Thus, an early release of AOS (O2 radical and H2O2) and a quick stimulation of a preferment anti-oxidant system (superoxide dismutases, catalases, and peroxidases) was observed for cv. Fougamou as compared to cv. Grande Naine for which a late and weak generation of AOS accompanied by a late stimulation of the anti-oxidant systems were detected.  相似文献   
110.
干旱胁迫对甘蔗近缘材料抗氧化系统酶活性的影响   总被引:2,自引:0,他引:2  
本文报道了在干旱胁迫条件下甘蔗栽培种ROC22和ROC16与近缘种果蔗、大茎野生种、斑茅、割手密抗氧化系统相关酶活性的变化情况。结果表明:斑茅的POD、CAT活性和可溶性蛋白含量均最高,推测其是抗旱性强的材料。另外,甘蔗野生的近缘种斑茅、割手密、果蔗、大野的SOD、POD、CAT酶活性和可溶性蛋白含量均明显高于栽培种ROC22和ROC16,可以认为野生的甘蔗近缘种材料抗旱性高于栽培种。不同胁迫时间与SOD、POD、CAT酶活性存在一定的相关性,与可溶性蛋白含量存在负相关性。  相似文献   
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