水分亏缺条件下草莓幼苗几个水分生理指标的变化

在离体脱水和不同浓度蔗糖溶液培养条件下,对草莓幼苗的脂质过氧化作用产物丙二醛、过氧化物歧化酶、细胞膜相对透性和组织相对含水量的变化及其相互关系进行研究。结果表明:随着组织相对含水量降低,丙二醛含量增高,细胞膜相对透性增大;丙二醛含量和组织相对含水量之间呈负相关;r新茎=0.89(HS),r叶片=0.75(HS),组织细胞膜相对透性随着丙二醛含量的增高而增大;在离体条件下过氧化物歧化酶对丙二醛含量增高有一定抑制作用。     

乳汁中超氧化物歧化酶(SOD)活性测定方法的研究

乳汁不但营养价值高，而且具有一定的医疗保健作用。其中含有的SOD，不但对哺育下一代是不可缺少的，而且对乳的本身也起到抗氧化的保鲜作用。水试验对影响邻苯三酚自氧化法测定SOD活性的诸因素进行了探讨，摸索出了适合于乳汁中SOD活性测定方法，为深入研究乳汁中SOD提供了重要的实验手段。     

桑叶超氧物歧化酶（SOD）的研究

分别用高速冷冻离心法和低速室温离心法提取了桐乡青、湖桑１９７、团头荷叶白、尖头荷叶白４个品种的顶芽、第５位和第１０位叶以及蚕沙残桑叶的ＳＯＤ粗酶液，然后用ＮＢＴ光还原法和聚丙烯酰胺凝胶电泳分别分析测定了它们的活性及其同工酶。试验结果表明：用高速冷冻离心法和低速室温离心法提取的ＳＯＤ，其活性无显著差异；同一叶位的桑叶ＳＯＤ活性在不同桑品种之间无显著差异；同一桑品种不同叶位的ＳＯＤ活性有显著差异；蚕沙残桑叶的ＳＯＤ活性与第１０位叶的ＳＯＤ活性相当。发现桑叶中有３～４种ＳＯＤ同工酶。     

NaCl胁迫对三色堇SOD、POD及叶绿素含量的影响

以三色堇幼苗叶片为试材,研究了不同浓度NaCl胁迫对其SOD、POD及叶绿素含量的影响。结果表明:随着NaCl胁迫浓度(0、50、100、150、200、250mmol/L)的增加,SOD、POD活性的变化表现为先下降后上升再下降的趋势,SOD在NaCl胁迫浓度(100mmol/L)活性最高,活性值为105.41U/g FW,POD在NaCl胁迫浓度(150mmol/L)活性最高,活性值为624.00U/g FW;叶绿素a、叶绿素b、叶绿素、类胡萝卜素含量呈先上升后下降趋势,叶绿素在NaCl胁迫浓度(100mmol/L)含量最高,值为1 929.99mg/g FW;在NaCl胁迫浓度为250mmol/L时,全株出现严重萎蔫,即该浓度为三色堇的致死浓度。     

Effects of α-lipoic acid, vitamins E and C upon the heat stress in Japanese quails

Antioxidant vitamins are commonly used as colorant, preventive, sweetener, nutritive and antioxidant materials in food industry. Thus, many studies have been conducted in recent years. We have performed the present study to understand the effects of α-lipoic acid (ALA), vitamin C and E, added into rations of Japanese quails, on chronic heat stress. This study was carried out in five groups as: control, stress, ALA, vitamin E and vitamin C groups. Heat stress is applied to all groups except the control group. Superficial pectoral muscles tissues were used for biochemical determinations. During the research, it is found that heat stress exerted undesired effects such as increasing lipid peroxidation (LPO) level indicating oxidative stress in Japanese quails. In addition, superoxide dismutase (SOD) and catalase (CAT) enzyme activities and glutathione (GSH) amounts were studied to understand the behaviour of defence mechanism. While stress increased LPO ratio, it was determined that all antioxidant added into the ration decreases LPO significantly (p < 0.05). In addition, it was determined that all of antioxidants added into ration effectively restored SOD activity and LPO ratio which heat stress affected negatively. Interestingly, vitamin C did not adjust GSH ratio in contrast to vitamin E and ALA, where vitamin E and C did not perform any positive effect on heat stress decreased CAT activity. Finally, it can be thought that antioxidant vitamins relatively ameliorated these undesired affects caused by stress factors given.     

Effects of stress on endocrine and metabolic processes and redirection: cross talk between subcellular compartments

Recent advances in genome analysis and biochemical pathway mapping have advanced our understanding of how biological systems have evolved over time. Protein and DNA marker comparisons suggest that several of these systems are both ancient in origin but highly conserved into today's evolved species. However, remnants of some of the more ancient functions of these chemical systems can run in conflict with the functions that those same pathways serve in complex organisms and tissue systems today. Relevant to the present topic, nitric oxide (NO) and superoxide anion (O₂^•−), ancient cellular molecules in evolutionary terms, are recognized today as both necessary for the well-being and stable health of cells but also injurious to cells as elaborated in conjunction with the cellular stress response. Why the dichotomy? This question underlies one of the basic issues challenging researchers as well as practitioners in their approach to disease management. The fundamental proinflammatory response of the innate immune system of the host is needed for pathogen control but can be injurious to tissues from “collateral damage” from NO- and O₂^•−-derived reactive molecules capable of affecting protein function via post-translational chemical modification. This review highlights newer aspects of the biochemistry of the NO- and O₂^•−-mediated innate proinflammatory response and further show how protein and tissue damage via overproduction of reactive nitrogen and oxygen intermediary molecules such as peroxynitrite (ONOO⁻) might be targeted to specific epitopes of proteins. Changes in the regulation of metabolism in response to proinflammatory disease states are discussed for GH signal transduction and tissue specificity.     

外源水杨酸诱导玉米纹枯病抗性的生理机制

分别以抗、感纹枯病的玉米自交系CML429、DM9为材料,研究接种纹枯病菌后喷施水杨酸对玉米叶片过氧化物酶、超氧化物歧化酶活性及产量的影响。结果表明,接种纹枯病菌后5d内,两玉米自交系叶片SOD活性先下降后升高并回到初始水平,而POD活性则表现持续的升高,CML429的SOD、POD活性均明显高于DM9。用不同浓度的水杨酸处理玉米叶片后,两个玉米自交系的SOD活性均逐渐下降,而POD则先略有下降后逐渐升高,在达到高峰后大部分处理有所回落。此外,所有外源水杨酸处理均能增强高感玉米自交系DM9对纹枯病的抗性,明显提高玉米产量,平均产量比对照高17．97％,而对抗性自交系的产量没有明显效果,以0．5mmol／L的处理效果最好。因此,外源水杨酸处理能降低玉米植株体内的活性氧水平,减轻纹枯病菌的伤害。     

茶树Mn-SOD基因在大肠杆菌中的高效表达

聚合酶链式反应(PCR)扩增茶树嫩叶锰超氧化物歧化酶基因,并与原核表达载体pET22b( )连接,构建重组质粒pET/msod,将该质粒转化至大肠杆菌Escherichia coliBL21(DE3),获得转基因工程菌BL21-pET/msod。在1 mmol.L-1异丙基硫代-β-半乳糖苷(IPTG)诱导下,重组蛋白得到高效表达,酶活性可达2×105U.L-1。SDS-PAGE检测表达蛋白分子量为25 kD,与通过核苷酸推测的分子量一致。     

过路黄对低温胁迫的生理反应

为探明过路黄低温致伤的生理特性，为其引种北移、栽培推广提供理论依据，研究了在低温（10，5，0，-5℃）胁迫下过路黄叶片内部生理生化反应的变化情况．结果表明，在低温胁迫下，过路黄叶片的质膜透性、保护酶活性和渗透调节物质均有明显的变化．在试验处理范围内，随着低温胁迫程度的加深和时间的延长，过路黄叶片的质膜透性上升；超氧化物歧化酶（SOD）活性先上升，后下降；游离脯氨酸（Pro）含量有明显增加；丙二醛（MDA）含量呈逐渐上升趋势．     

烯草酮、氯氰菊酯和2-4D丁酯对中华摇蚊（Chironomussinicus）幼虫的急性毒性试验

[目的]评价农药对水生生物的毒理效应。[方法]采用静水法研究烯草酮、氯氰菊酯和2．4D丁酯对中华摇蚊（Chironomussinicus）幼虫的急性毒性效应。分别设定不同浓度梯度进行急性暴露试验,于48h时测定摇蚊幼虫组织匀浆超氧化物歧化酶（SOD）的活性。[结果]在氯氰菊酯和2-4D丁酯处理摇蚊幼虫后12h后,不同浓度间的存活率无显著差异,在48h时随着农药浓度的增加,存活率F降。烯草酮、氯氰菊酯和2-4D丁酯对中华摇蚊幼虫48h的LC。分别为1．842、0．150和1．999mg／L,氯氰菊酯对中华摇蚊幼虫的毒性最高．其次为烯草酮,2-4D丁酯毒性最低。烯草酮对中华摇蚊幼虫组织SOD含量有明显影响．表现出剂量-效应关系;2-4D丁酯对组织SOD含量有明碌影响．但未表现出剂量-效应关系：而氯氰菊酯对组织SOD含量则无明显影响。[结论]该研究为水体污染监测和水环境中农药的残留提供理论依据。