抗氰交替途径参与马铃薯软腐病菌对马铃薯块茎的侵染

马铃薯软腐病菌中的强致病菌Ｅｃｃ、弱致病菌Ｅｃｃｂ在马铃薯块茎中诱导抗氰交替途径运行的能力依次为Ｅｃｃ、Ｅｃｃｂ。即病原菌的致病性越强,诱导抗氰交替途径的能力越强,显示病原菌对寄主植物的侵染过程与寄主植物体内抗氰交替途径的运行密切相关。ＳＨＡＭ抑制剂试验表明病原菌对寄主植物的侵染过程中寄主植物中抗氰交替途径的运行可增强寄主植物的感病性。信号传导试验显示ＬａＣｌ３、ＬｉＣｌ可通过促进体内抗氰交替途径     

马铃薯块茎切片伤诱导抗氰呼吸的研究

马铃薯块茎新鲜切片呼吸中不存在抗氰的交替途径。相反,陈化24小时切片的伤诱导呼吸不仅相当抗氰,而且在氰化物(CN~-)存在和不存在时都被间-氯苯氧肟酸(m-CLAM)抑制,证明有交替途径运行。据测定,在陈化切片伤诱导呼吸中,交替途径和细胞色素途径分别约占总呼吸的28%和54%。当受 CN~-抑制时,交替途径的最大运行量(V_(alt))大于实际运行量(ρ·V_(alt)),表明电子流可能从细胞色素主路转向交替途径。当用碘乙酸和丙二酸抑制以降低陈化切片呼吸流时,KCN 和 m-CLAM 各自抑制呼吸的百分比并无改变,说明关于电子流量是控制交替途径“开关”的看法还不能完全得到证实。     

水杨酸对陈化马铃薯切片交替途径活性的诱导作用

在马铃薯切片陈化过程中,总呼吸速率（Ｖｔ）和交替途径容量（Ｖａｌｔ）分别升高了５倍和２８倍,但交替途径在无ＫＣＮ存在下几乎不运行。用２０μｍｏｌ／Ｌ的水杨酸处理陈化切片可引起总呼吸速率和交替途径容量的少量增加,但交替途径的运行却明显加强。水杨酸的这种促进作用在Ｐｅｒｃｏｌｌ纯化的线粒体中也有出现。马铃薯切片中交替途径运行的增加导致了线粒体呼吸控制比及ＡＤＰ／Ｏ的下降。这些都表明水杨酸对马铃薯切片陈化过程中抗氰交替途径的活性具有诱导作用。     

植物-病原物互作过程中的活性氧

活性氧与水分胁迫、环境污染、衰老及低温等方面的关系已有大量的报道。在植物－病原物互作过程中,病原物作为一种特殊的胁迫因子而起作用。近年来对植物一病原物互作过程中活性氧的研究已成为植物病理生理学研究的一个热点,本文对此作一综述。１植物─-病原物巨作过程的活性氧的产生在正常情况下,植物体内活性氧（ａｃｔｉｖｅｏｘｙｇｅｎｓｐｅｃｉｅｓ,ＡＯＳ,包括超氧阴离子Ｏ－２;过氧化氢Ｈ２Ｏ２;氢氧自由基ＯＨ;单线态氧１Ｏ２）处于低水平状态,在植物过敏性反应（ＨＲ）早期阶段常出现ＡＯＳ迅速释放,这种ＡＯＳ迅速释…     

烟草—TMV相互作用中质膜NADPH氧化酶的组装

比较 Ｎ Ｎ 烟草（与烟草花叶病毒（ Ｔ Ｍ Ｖ）发生非亲和相互作用）和普通烟草 ３００２ 品种（与 Ｔ Ｍ Ｖ 发生亲和相互作用）在烟草— Ｔ Ｍ Ｖ 的相互作用中质膜 Ｎ Ａ Ｄ Ｐ Ｈ 氧化酶的组装激活、产生活性氧的差异．用两相法制备密闭的正向型质膜（ Ｐ Ｍ）囊泡,以 Ｓ Ｏ Ｄ 敏感的 Ｎ Ａ Ｄ Ｐ Ｈ 依赖的 Ｃｙｔ ｃ 的还原表示 Ｎ Ａ Ｄ Ｐ Ｈ 氧化酶的活性,用人类噬中性白细胞 Ｎ Ａ Ｄ Ｐ Ｈ 氧化酶亚基 ｐ４７ ｐｈｏｘ 的抗体对烟草叶片蛋白进行免疫学检测．结果显示在两种烟草叶片胞质中均存在与 ｐ４７ ｐｈｏｘ 亚基的抗体发生免疫交叉反应的相同分子量的蛋白,该蛋白在 Ｔ Ｍ Ｖ 侵染 Ｎ Ｎ 基因烟草后可向质膜发生转移,且伴随有氧化酶活性的升高．而对于普通烟草则无氧化酶膜组分和酶活性的明显变化．以上结果表明,烟草叶片质膜上存在与哺乳动物 Ｎ Ａ Ｄ Ｐ Ｈ 氧化酶相类似的氧化酶,它的组装和激活可能是烟草— Ｔ Ｍ Ｖ 非亲和相互作用早期活性氧的主要来源．     

真菌菌丝细胞壁提取物对马铃薯块茎组织抗干腐病的诱导效应

以马铃薯(品种'大西洋')块茎切片为材料,研究了马铃薯非亲和菌株粉红单端孢(Trichothecium roseum)菌丝细胞壁提取物处理对马铃薯块茎组织干腐病抗性的诱导效果及其机理.结果表明,150 μg/mL(以中性糖含量为标准)菌丝细胞壁提取物预处理马铃薯切片72 h后进行损伤接种能显著降低干腐病菌(Fusarium sulphureum)的侵染能力,预处理块茎的病斑直径仅为对照的43.6%;菌丝细胞壁提取物处理能显著增强与马铃薯块茎组织抗病相关的过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性.可见,粉红单端孢菌丝细胞壁提取物预处理能显著增强马铃薯块茎组织对干腐病的抗性,而且主要是通过提高马铃薯块茎组织中与抗病性相关酶的活性来实现的.     

铜对马铃薯块茎产量与生理生化特性的影响

铜对马铃薯块茎产量与生理生化特性的影响白嵩吕芳芝＊白宝璋李秀坤刘志清＊＊陈文荣（吉林农业大学,长春１３０１１８）ＥＦＦＥＣＴＳＯＦＣＯＰＰＥＲＯＮＴＵＢＥＲＹＩＥＬＤＡＮＤＰＨＹＳＩＯ┐ＬＯＧＩＣＡＬＡＮＤＢＩＯＣＨＥＭＩＣＡＬＣＨＡＲＡＣ┐ＴＥＲ...     

苹果的抗氰呼吸与果实呼吸跃变的关系

苹果在发育期间呼吸对ＫＣＮ敏感,进入跃变期时呼吸为ＫＣＮ不敏感,但对间氯苯氧肟酸（ＣＬＡＭ）敏感。跃变期的苹果切片陈化后有诱导呼吸发生,且ＫＣＮ与ＣＬＡＭ对诱导呼吸都有一定的抑制作用。当在ＣＬＡＭ存在下进行陈化时,苹果诱导呼吸的发生被抑制约３０％,跃变期果实的特点是当果实进入成熟期时呼吸途径发生了由细胞色素途径向抗氰的交替途经转移的现象;同时其果实切片在陈化后可以发生诱导呼吸。     

活性氧中间体和NO在植物抗病中的作用

植物与病原菌互作时,活性氧中间体(reactiveoxygenintermediates,ROI)和一氧化氮(NO)参与了植物抗病性的建立。寄主与病原菌非亲合性互作产生二次氧爆发高峰,体内NO增加。许多氧化酶可以催化氧爆发产生ROI。ROI和NO通过氧化还原信号启动寄主细胞局部的过敏性坏死反应和全株系统获得性抗病性。     

用人工合成的丁型肝炎病毒抗原多肽检测丁肝病毒IgM抗全及其初步应用

用人工合成的丁型肝炎病毒抗原（ＨＤＶ－Ａｇ）肽建立了检测抗ＨＤＶ－ＩｇＭ抗体的ＥＬＩＳＡ方法。本法操作简便、快速、重复性好、特异性强,与抗ＨＡＶ－ＩｇＭ＇抗ＨＢｃ－ＩｇＭ、抗ＨＢｓ－ＩｇＭ、抗ＨＣＶ－ＩｇＭ、抗ＣＭＶ－ＩｇＭ、抗ＲＶ－ＩｇＭ、类风湿因子（ＲＦ）及抗核抗体（ＡＮＡ）阳性血清均不起反应,且可被２－巯基乙醇阻断而不起反应。经初步临床应用,３１例正常人血清抗ＨＤＶ－ＩｇＭ全部阴性,２８例慢     

Cyanide-resistant respiration in roots and leaves. Measurements with intact tissues and isolated mitochondria

A comparison was made between the oxygen uptake of roots and leaves and of mitochondria isolated from the same tissues. Ten species were included in this study: three legumes, one C3-monocotyledon, one C4-monocotyledon, the rest non-leguminous C3-dicotyledons. Root and leaf respiration in all species examined displayed substantial resistance to KCN (0.1–1.0 mM) and the cyanide-resistant respiration was completely inhibited by salicylhydroxamic acid (SHAM; 10–20 mM). SHAM alone inhibited oxygen uptake to varying degrees, depending on the species. Mitochondria were isolated from roots and leaves of many of the species examined and also displayed cyanide-resistant oxygen uptake, which was sensitive to both SHAM and tetraethylthiuram disulfide (disulfiram). Concentrations of SHAM greater than 2 mM caused inhibition of the cytochrome path as well as of the alternative path in isolated mitochondria. Respiration rates of intact roots and leaves in the presence of varying concentrations of SHAM alone were plotted against those obtained in the presence of both SHAM and KCN. This plot showed that in vivo the cytochrome pathway was not affected by 10 or 20 mM SHAM in the external solution. We conclude that the activity of the alternative pathway in intact roots and leaves can be reliably estimated by comparing SHAM-sensitivity and cyanide-resistance of respiration.     

Effects of KCN and Salicylhydroxamic Acid on the Root Respiration of Pea Seedlings

Polarography, using cylindrical platinum electrodes, proved suitable for measuring changes in the internal apical O₂ concentration of the primary root of pea (Pisum sativum L. cv Meteor) effected by KCN and/or salicylhydroxamic acid (SHAM) in the bathing medium. An electrical rootaeration analog was used to help evaluate some of the results. Concentrations of KCN ≤0.05 millimolar had no significant effect. In response to 0.1 millimolar KCN, the O₂ concentration rose substantially for approximately 2 hours, then declined, and after 10 hours had frequently fallen below the pretreatment level. Such changes suggest an initial inhibition of cytochrome oxidase-mediated O₂ uptake followed by an induction of the alternative, cyanide-resistant respiratory pathway. These treatments proved nonlethal. Changes in O₂ concentration similar to those described for 0.1 millimolar KCN were observed in response to 1 and 10 millimolar KCN but these treatments were lethal and the root apex became soft and often appeared flooded. Roots survived and showed no significant responses when treated with SHAM at concentrations ≤5 millimolar. However, when the alternative pathway had been (apparently) induced by 0.1 millimolar KCN, the addition of 5 millimolar SHAM to the bathing medium caused a substantial and persistent rise in the root apical O₂ concentration, suggesting that this (nonlethal) concentration of SHAM could indeed inhibit O₂ uptake via the cyanide-resistant pathway.

It is concluded that while O₂ uptake normally occurs by the cytochrome pathway in the primary pea root, the alternative, cyanide-resistant pathway can be induced by 0.1 millimolar KCN.

     

干旱与条锈病复合胁迫对小麦的生理影响

以抗旱性和抗病性不同的小麦为材料,以正常生长为对照,观察了病原菌和水分复合胁迫对小麦叶片相对含水量、活性氧代谢以及对抗氰呼吸的发生、运行的影响。讨论了在干旱与病原菌侵染复合胁迫下,抗氰呼吸在植物抗逆机制中所扮演的角色。复合胁迫下,抗病小麦显然具备更强的水分调控能力,而感病品种不能有效控制病叶水分散失。水分胁迫能引起抗氰呼吸的下降,但不能抵消因病原菌侵染引起的抗氰呼吸的增强,条锈菌侵染对小麦抗氰呼吸的影响远远大于水分胁迫。病原菌侵染和水分复合胁迫下,活性氧产生的速率表现出累加效应,而抗氰呼吸表现出和基质抗氧化酶的活性互补。植物交替氧化酶在干旱与病原菌侵染复合胁迫中具有重要的抗氧化功能,并可能调节着逆境下物质与能量需求间的矛盾。     

The appearance and characterization of cyanide-resistant respiration in the fungus Candida albicans

The respiration of yeast-form cells of the dimorphic fungus Candida albicans became resistant to cyanide during aging treatment in the resting state. An alternative, cyanide-resistant respiratory pathway was found to develop fully in cells aged at a concentration of 0.75 X 10(9)/ml or more at 25 C, but did not appear at 5 C. Chloramphenicol did not prevent the appearance of the alternative respiratory pathway. The effects of inhibitors, salicylhydroxamic acid (SHAM) and disulfiram (tetraethylthiuram disulfide), on respiration of aged cells were examined, and results indicated that SHAM binds at a site on the alternative respiratory pathway whereas disulfiram binds at two sites, one on the conventional respiratory pathway and the other on the alternative pathway. Thus, SHAM is a more selective inhibitor of the alternative respiration of C. albicans cells. SHAM-titration of the alternative respiration revealed that less than 10% of the maximal activity of the alternative respiratory pathway was utilized under normal conditions, indicating that the alternative respiratory pathway makes a small contribution to the total respiration. It was therefore concluded that the alternative, cyanide-resistant respiratory pathway operates fully when the cyanide-sensitive, cytochrome pathway is blocked although aged cells possess both respiratory pathways.     

An alternative respiratory pathway on Candida krusei: implications on susceptibility profile and oxidative stress

Our aim was to detect the presence of an alternative oxidase (AOX) in Candida krusei clinical strains and its influence on fluconazole susceptibility and in reactive oxygen species (ROS) production. Candida krusei clinical isolates were tested to evaluate the presence of AOX. Debaromyces hansenii 2968 (AOX positive) and Saccharomyces cerevisiae BY4742 (AOX negative) were used as control strains. Measurements of oxygen consumption were performed in the presence of 1?mM KCN, an inhibitor of the classical respiratory chain, and 5?mM salicylhydroxamic acid (SHAM). AOX expression was monitored by Western blotting using an AOX monoclonal antibody. Interactions between fluconazole and SHAM were performed using checkerboard assay. ROS production was evaluated in the presence of SHAM plus fluconazole, H(2) O(2) , menadione, or plumbagin. AOX was present in all C.?krusei tested. The combination of fluconazole with SHAM resulted in an indifferent effect. In the presence of SHAM, the treatment with ROS inductors or fluconazole increased ROS production, except in the AOX-negative strain. An alternative respiratory pathway resistant to cyanide is described for the first time as a characteristic of C.?krusei species. This AOX is unrelated to fluconazole resistance; however, it protects C.?krusei from oxidative stress.     

Cyanide-Resistant Respiration in Suspension Cultured Cells of Nicotiana glutinosa L

The respiration of dark-grown Nicotiana glutinosa L. cells in liquid suspension culture was found to be highly cyanide resistant and salicylhydroxamic acid (SHAM) sensitive, indicative of an active alternative respiratory pathway. This was especially true during the lag and logarithmic phases of the 14-day growth cycle. Mitochondria isolated from logarithmically growing cells exhibited active oxidation of malate, succinate, and exogenous NADH. Oxidation of all three substrates had an optimum pH of 6.5 and all were highly resistant to inhibited by cyanide and sensitive to SHAM. Respiratory control was exhibited by all three substrates but only if SHAM was present to block the alternative pathway and divert electrons to the phosphorylating cytochrome pathway. The cyanide-resistant oxidation of exogenous NADH has previously only been associated with Arum spadix mitochondria. Coemergence during evolution of the alternative respiratory pathway and the exogenous NADH dehydrogenase in plant mitochondria as a possible mechanism for removal of cytoplasmic NADH is proposed. Evidence is presented which suggests that mitochondrial assays should be performed at pH 6.5.     

Effects of cyanide, salicylhydroxamic acid, and temperature on respiration and germination of spores of the fern Sphaeropteris cooperi

During the first 96 h of culture, germinating spores of the fern Sphaeropteris cooperi (F. v. Muell.) Tryon showed a gradual rise in respiratory activity to a maximum of about 6.5 μl 0₂ h⁻¹ mg⁻¹ dry wt. This was followed by a transitory decline in rate, concluded by a second respiratory rise preceding the emergence of the rhizoid after 192 h of culture. Oxygen uptake during the first 120 h of germination was insensitive to 1 m M potassium cyanide (KCN) but was inhibited by 1 m M salicylhydroxamic acid (SHAM); however, beyond this time cyanide showed increasing inhibitory effectiveness whereas SHAM became less effective. Regardless of time of application, KCN had no effect on germination. Maximum inhibition of germination by SHAM was achieved if applied up to 120 h after culture initiation, after which spores became insensitive to SHAM. Heat treatment (50°C for 90 min) during the cyanide-resistant phase of respiration (0 h–120 h) induced cyanide-sensitive respiration and completely inhibited spore germination. Elevated temperatures had little effect if applied during the cyanide-sensitive phase (beyond 120 h). Temperature inhibited spores regained their ability to germinate if maintained in culture until the cyanide-resistant pathway was restored and then subjected to a second photoinductive light treatment. These results suggest the presence and possible involvement of the cyanide-resistant, alternative respiratory pathway during germination of Sphaeropteris cooperi spores.     

Binding of Butyl Gallate to Plant Mitochondria : II. Relationship to the Presence or Absence of the Alternative Pathway

[¹⁴C]butyl gallate was used in binding studies to investigate the cyanide-resistant respiratory pathway in mitochondria isolated from a variety of sources displaying varying levels of cyanide resistance. Highly cyanide-resistant mitochondria were isolated from aroid spadices, while moderately cyanide-resistant mitochondria were isolated from either mung bean (Vigna radiata L.) hypocotyls or carbon dioxide/oxygen/ethylene-treated tubers. Totally cyanide-sensitive mitochondria were isolated from untreated tubers and rat liver. With one exception, all the plant mitochondria showed a reversible butyl gallate binding site which saturated at a level of 1.0 to 2.0 nanomoles per milligram protein. The exception, freshly harvested white potato tubers (<1 month from harvest), showed little specific butyl gallate binding, and also showed no appreciable induction of the cyanide-resistant pathway following carbon dioxide/oxygen/ethylene treatment. Only a low level, linear binding, well below that seen with plant mitochondria, was observed with rat liver mitochondria. Taken together, these results suggest a model for the interaction of the alternative pathway with the cytochrome pathway. In this model, the butyl gallate binding site (alternative oxidase) is a constitutive component in those mitochondria that are capable of developing the alternative pathway, and the binding sites associated with a second, inducible component that functions to couple the oxidase to the cytochrome pathway.