光照下菜豆叶片抗氰呼吸与光合作用关系的分析北大核心CSCD

为了进一步了解光照下植物呼吸作用的内在机理以及呼吸作用和光合作用的关系,该文研究了在光照下菜豆(Phaseolus vulgaris)叶片抗氰呼吸与光合作用的关系。研究发现,将黑暗下生长的菜豆幼苗叶片转到光照下10 h,总呼吸、抗氰呼吸以及抗氰呼吸在总呼吸中的比例均逐步上升;光照也导致了叶片叶绿体光合放氧和CO2固定的出现及其速率的增加,但光合放氧和CO2固定速率的增加均滞后于抗氰呼吸的增加。将黑暗下生长的叶片转到光照下之前用抗氰呼吸的抑制剂水杨基氧肟酸(SHAM)处理叶片,发现用SHAM处理并没有导致叶片在光照下光合放氧和CO2固定速率的明显变化,这也提示了黑暗下生长的叶片转至光照的过程中,抗氰呼吸和光合作用没有产生偶联。进一步研究发现,在黑暗中对叶片施加短时间的光照能够增加抗氰呼吸在总呼吸中的比例,但短时间的光照对叶片光合CO2固定速率没有影响。这些结果表明了光照对抗氰呼吸的诱导可以不依赖于光合作用,光照可能是作为一种直接的信号去诱导抗氰呼吸。     

Cyanide-resistant Respiration in Freshly Cut Potato Slices

Treating intact white potato (Solanum tuberosum L.) tuber with ethylene in air or O₂ made it possible to obtain freshly cut slices which exhibit cyanide-resistant respiration. The cyanide-resistant path requires induction in whole tubers. The data also indicate that high O₂ concentration is necessary for the full development of cyanide-resistant respiration.     

Cyanide-resistant alternative respiration is strictly correlated to intracellular peroxide levels in Acremonium Chrysogenum

A strict correlation between the intensity of the cyanide-resistant alternative respiratory pathway and the intracellular peroxide levels in the cephalosporin C producer filamentous fungus Acremonium chrysogenum was demonstrated. Intracellular peroxide levels increased in a dose-dependent manner after addition of H₂O₂ to the culture media. A similar phenomenon was observed due to the specific inhibition of catalase by salicylic acid. In both cases, cyanide-resistant respiration was markedly stimulated. On the other hand, both cyanide-resistant respiration and intracellular peroxide levels were effectively suppressed by the lipid peroxyl radical scavenger DL-α-tocopherol, which breaks lipid peroxidation chains effectively. Our findings firmly supported the assumption that there is a connection between the intracellular peroxide levels and the intensity of the alternative respiratory pathway in fungi.     

Salicylic Acid induces cyanide-resistant respiration in tobacco cell-suspension cultures

Cyanide-resistant, alternative respiration in Nicotiana tabacum L. cv Xanthi-nc was analyzed in liquid suspension cultures using O₂ uptake and calorimetric measurements. In young cultures (4-8 d after transfer), cyanide inhibited O₂ uptake by up to 40% as compared to controls. Application of 20 μm salicylic acid (SA) to young cells increased cyanide-resistant O₂ uptake within 2 h. Development of KCN resistance did not affect total O₂ uptake, but was accompanied by a 60% increase in the rate of heat evolution from cells as measured by calorimetry. This stimulation of heat evolution by SA was not significantly affected by 1 mm cyanide, but was reduced by 10 mm salicylhydroxamic acid (SHAM), an inhibitor of cyanide-resistant respiration. Treatment of SA-induced or uninduced cells with a combination of cyanide and SHAM blocked most of the O₂ consumption and heat evolution. Fifty percent of the applied SA was taken up within 10 min, with most of the intracellular SA metabolized in 2 h. 2,6-Dihydroxybenzoic and 4-hydroxybenzoic acids also induced cyanide-resistant respiration. These data indicate that in tobacco cell-suspension culture, SA induces the activity and the capacity of cyanide-resistant respiration without affecting the capacity of the cytochrome c respiration pathway.     

丙酮酸对陈化马铃薯块茎切片线粒体抗氰呼吸的激活作用

用从陈化马铃薯切片纯化的线粒体进行实验发现：丙酮酸对总呼吸只有微弱的刺激作用,但可明显激活抗氰呼吸,并显著增强抗氰呼吸对总呼吸的贡献;丙酮酸对抗氰呼吸的激活作用可通过洗涤线粒体除去,重新加入丙酮酸又对抗氰呼吸产生激活作用;丙酮酸对抗氰呼吸的半最大激活浓度约为1．0mmol／L。上述结果表明丙酮酸对植物线粒体抗氰呼吸的激活作用可能具有普遍性。     

白假丝酵母菌耐药与抗氰呼吸的相关性研究

目的探讨白假丝酵母菌的耐药情况及其与抗氰呼吸的相关性。方法用真菌药敏测定试剂盒测定从临床分离出来的37株白假丝酵母菌的耐药性,并从中选出5株耐药菌和5株敏感菌进行抗氰呼吸的研究。结果白假丝酵母菌对益康唑的耐药率最高,达54.1%,耐药白假丝酵母菌的抗氰呼吸速率均值为(17.56±6.75)nmol/(min.A620),敏感白假丝酵母菌的抗氰呼吸速率均值为(7.99±5.80)nmol/(min.A620),耐药白假丝酵母菌的抗氰呼吸速率明显升高,且耐药菌株抗氰呼吸速率占总呼吸的比例明显高于敏感菌株(P0.05),差异具有显著性。结论兰州市区白假丝酵母菌对益康唑耐药性较高,且白假丝酵母菌的耐药与抗氰呼吸途径相关。     

Characterization of cyanide-resistant respiration and appearance of a 36 kDa protein in mitochondria isolated from antimycin A-treated Hansenula anomala

Mitochondria exhibiting cyanide-resistant respiration were isolated from Hansenula anomala which had been incubated in the presence of antimycin A to induce cyanide-resistant respiration. The cyanide-resistant respiration in isolated mitochondria was not inhibited by antimycin A or myxothiazol, suggesting that the branching of the pathway from the normal cyanide-sensitive pathway takes place at the coenzyme Q level. Analysis of mitochondrial proteins by sodium dodecyl sulfate gel electrophoresis indicated that a 36 kDa protein was induced by antimycin A treatment of the yeast. It is suggested that this protein is a component of the cyanide-resistant respiratory pathway.     

Changes in respiration of mitochondria isolated from cotyledons of ethylene-treated pea seedlings

Treatment of intact, germinating pea (Pisum sativum L. cv. Homesteader) seedlings with ethylene enhanced the cyanide-resistant respiration of mitochondria isolated from the cotyledons. The level of enhancement depended on the concentration of ethylene. Thus, exposure to 0.9 l·l^-1 of ethylene in air for days 4–6 of germination had little effect on cyanide-resistant respiration, while exposure to 130 l·l^-1 increased it from 10 to 50 nmol O₂·min^-1·(mg protein)^-1. The length of exposure to ethylene also affected the degree of enhancement. According to some literature data, lipoxygenase (EC 1.13.11.12) activity can be mistaken for cyanide-resistant respiration, but in our preparations of purified pea mitochondria ethylene had no effect on lipoxygenase activity, nor did the gas disrupt the outer mitochondrial membrane. Bahr and Bonner plots of respiration in the presence of salicylhydroxamic acid (SHAM) indicated that ethylene did not affect respiration proceeding via the cytochrome pathway. Thus, increases in total respiration in mitochondria from cotyledons of ethylene-treated pea seedlings reflect increases in cyanide-resistant respiration.Abbreviations Cyt c cytochrome c - SHAM salicylhydroxamic acid     

干旱胁迫对小麦幼苗抗氰呼吸和活性氧代谢的影响

研究了干旱胁迫对抗旱性强弱不同的两种小麦幼苗的抗氰呼吸和活性氧代谢的影响。干旱胁迫导致了两种小麦抗氰呼吸活性及基因转录水平的下降,但抗旱品种在轻度干旱胁迫下表现出一定的适应能力,其抗氰呼吸活性及基因转录水平均高于不抗旱品种。干旱胁迫下,对干旱敏感的小麦幼苗叶片中活性氧含量高于抗旱小麦;3种抗氧化酶的活性低于抗旱小麦的3种抗氧化酶的活性。据此认为,严重的干旱胁迫引起活性氧含量的增加扰动了活性氧与抗氰呼吸之间的应答平衡,但抗氰呼吸可能通过清除活性氧等机制而起了抗旱的作用。     

Cyanide-resistant respiration of Pseudomonas aeruginosa bacteria]

The transition of the bacterial culture into the stationary growth phase is accompanied by an appearance of cyanide-resistant respiration. Chloramphenicol inhibits the development of cyanide-resistant respiration. The cyanide-resistant oxidase is localized in the bacterial membrane. Its appearance is not due to the quantitative and qualitative changes of flavins, non-heme iron, ubiquinone and cytochromes of the b and c types, but is accompanied by an increase in the copper content of the membrane preparations. Neither cyanide-sensitive, nor cyanide-resistant chains of the bacterial electron transfer contain cytochromes of the a type. The cyanide-resistant oxidase accepts electrons at the ubiquinone--cytochrome b level of the main respiratory chain. The cyanide-resistant respiration is not accompanied by a formation of hydrogen peroxide. Cytochrome o performs the function of cyanide-sensitive oxidase. The nature of cyanide-resistant oxidase still remains obscure.     

A 36-kDa mitochondrial protein is responsible for cyanide-resistant respiration in Hansenula anomala

Antimycin A-dependent induction of cyanide-resistant respiration in Hansenula anomala was reversibly blocked by carbonylcyanide-m-chlorophenylhydrazone (CCCP). When the cells were pulse-labeled with [35S]methionine in the presence of both antimycin A and CCCP, the radioactivity was incorporated into a 39 kDa mitochondrial protein. Upon removal of CCCP, this protein was processed into a 36 kDa form. The increase in the 36 kDa protein completely paralleled that in cyanide-resistant respiration activity, suggesting that the 39 kDa protein is the precursor of the 36 kDa protein, which is responsible for cyanide-resistant respiration.     

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。     

Effect of inhibitors of two isoprenoid biosynthetic pathways on physiological and biosynthetic characteristics of <Emphasis Type="Italic">Dioscorea deltoidea</Emphasis> cell suspension culture

The effect of phosmidomycin and mevinolin, which inhibit MEP and MVA isoprenoid biosynthetic pathways, respectively, on the growth (biomass accumulation, growth index, specific growth rate), physiological (respiration intensity and ratio between the cytochrome and cyanide-resistant respiration types), and biosynthetic (steroid glycoside biosynthesis) characteristics of the cell suspension culture of Dioscorea deltoidea Wall. has been studied. Both inhibitors decreased the growth index of a cell culture by 20–25%, but their influence on the cell growth dynamics was different. Mevinolin treatment reduced the maximum biomass accumulation by 20% as against the control but did not change the character of a growth curve. Phosmidomycin treatment caused a significant growth delay (a 6-day lag phase) followed by a short active growth period (μ = 0.29 days^-1). Treatment of cells with inhibitors did not significantly influence on their total oxygen uptake rate, whose average value at different growth phases was equal to 100–200 mg О₂/g of dry cell weight per hour, but cardinally changed characteristics of respiratory metabolism. The inhibitors increased the activity of a cyanide-resistant respiration and decreased the intensity of a cytochrome respiration; each inhibitor worked in its specific manner. In the case of mevinolin, the maximum level of cyanide-resistant respiration (70% of the total respiration intensity) was observed at initial growth phases; during the further cell culture growth, this value gradually reduced to 6–8%. Phosmidomycin treatment caused a reverse dynamics: at the initial growth phases, the contribution of cyanide-resistant respiration was 30%, whereas at the stationary and degradation phases it increased to 50–60%. The treatment of cells with phosmidomycin resulted in a double increase in the content of furostanol glycosides at the stationary growth phase, whereas the use of mevinolin-containing medium reduced the content of these compounds as against the control. Inhibitors also influenced on the ratio of individual glycosides, such as protodioscin, deltoside, and their 26-S-isomers. The obtained results confirm the hypothesis of a possible intermediate exchange between the plastid (MEP) and cytosolic (MVA) isoprenoid biosynthetic pathways; this exchange is directed mainly from the plastids to the cytosol.     

On the absence of correlation between cyanide-resistant respiration and cytochrome d content in bacteria

The regularity of appearance of cyanide-resistant respiration and cytochrome d in various bacteria as well as the relationship between the degree of resistance of respiration to cyanide and cytochrome d content was studied. Bacteria able to synthesize cyanide-resistant respiration were shown to appear during transition of culture to the stationary phase of growth caused by the exhaustion of carbon source. No regulatory of appearance of cytochrome d was observed. There is no correlation between the degree of resistance to cyanide and cytochrome d content. It was concluded that the cyanide-resistant respiration of bacteria and eukaryotic microorganisms may be associated with the functioning of a non-cytochrome nature oxidase.     

Cyanide-resistant respiration of Physarum polycephalum in course of starvation

The inhibition of respiration of $\text{Physarum polycephalum}$ microplasmodia by KCN varies between 30% and 70% of initial rate of O₂ uptake, depending on the time of starvation. The kinetics of the development of cyanide-resistant respiration and its sensitivity toward salicylhydroxamic acid (SHAM) point out that CN-resistant respiration represents the activity of the alternative pathway of the electron transport. There is no evidence that during starvation the alternative pathway of respiration is active in the absence of cyanide.     

Cyanide-insensitive Respiration in Pea Cotyledons

Mitochondria isolated by a zonal procedure from the cotyledons of germinating peas possessed a cyanide-resistant respiration. This respiration was virtually absent in mitochondria isolated during the first 24 hours of germination but thereafter increased gradually until the 6th or 7th day of seedling development. At this time between 15 and 20% of the succinate oxidation was not inhibited by cyanide. The activity of the cyanide-resistant respiration was also determined in the absence of cyanide. Relationships among mitochondrial structure, cyanide-resistant respiration, and seedling development are discussed.     

Effect of limitation of bacterial growth with carbon, sulfur and iron on the synthesis of cytochromes, development of cyanide-resistant respiration and super-synthesis of metabolites

The work is concerned with the effect produced by limiting the growth of various bacteria with carbon, sulfur and iron on cytochrome synthesis, development of cyanide-resistant respiration and oversynthesis of metabolites. The cessation of bacterial growth due to the exhaustion of a carbon source was shown to be accompanied with the development of cyanide-resistant respiration though the oversynthesis of metabolites did not occur. If the growth was limited by a sulfur or iron source, the concentration of cytochromes a, b and c fell down as compared with that when the growth was limited by a carbon source, and metabolites were produced and accumulated in the medium. In that case, the respiration of virtually all the bacteria was inhibited by cyanide to a great extent. As was demonstrated for Pseudomonas aeruginosa, the development of cyanide-resistant respiration was inhibited when metabolites accumulated and then the respiration became completely resistant to cyanide as soon as the oversynthesis ceased. Apparently, whatever limits the bacterial growth, the process of oversynthesis inhibits cyanide-resistant oxidase.     

Possible role of a 36 kDa protein induced by respiratory inhibitors in cyanide-resistant respiration in Hansenula anomala

The antimycin A or cyanide-dependent appearance of a 36 kDa protein in the particulate fraction was observed in L-[35S]methionine pulse-labeling experiments on cells of Hansenula anomala, in which cyanide-resistant respiration was induced. The combined addition of cycloheximide or anaerobiosis, which block the induction of cyanide-resistant respiration, repressed the synthesis of this protein. These results suggest the involvement of the particulate 36 kDa protein in cyanide-resistant respiration.     

Relative Contribution of Cytochrome-mediated and Cyanide-resistant Electron Transport in Fresh and Aged Potato Slices

The respiration of fresh potato (Solanum tuberosum, var. Russet Burbank) slices is predominantly cyanide-sensitive whether in the presence or absence of uncoupler. By contrast, the wound-induced respiration which develops in thin slices with aging is cyanide-resistant, and in the presence of cyanide, sensitive to chlorobenzhydroxamic acid, a selective inhibitor of the cyanide-resistant respiration. Titration of the alternate path in coupled slices with chlorobenzhydroxamic acid, in the presence and absence of cyanide, shows that the contribution of the cyanide-resistant pathway to the wound-induced respiration is zero. Similar titrations with uncoupled slices reveal that the alternate path is engaged and utilized extensively.

The maximal capacity of the cytochrome path (V_cyt) has been estimated in fresh and aged slices in the presence of the uncoupler carbonyl-cyanide m-chlorophenyl hydrazone. It has been found that V_cyt of aged slices is but 30 to 40% higher than that of fresh slices. The results suggest that the bulk of the wound-induced respiration is mediated through the cytochrome pathway which exists in fresh slices in suppressed form, and which is fully expressed by slice aging. The engagement of the alternate path by uncouplers in aged slices is attributed to an increase in substrate mobilization, with the result that the electron transport capacity of the cytochrome chain is exceeded.