The Effect of Ecological Factors on Spore Germination and the Viability of the Mycelial Fragments of Microscopic Fungi

Spore germination and the viability of the mycelial fragments of the microscopic fungi Alternaria alternata, Penicillium spinulosum, and Mucor hiemaliswere studied with respect to the action of certain ecological factors: sucrose concentration (0, 0.2, 2, 10, and 100 g/l), temperature (4, 20, 25, and 30°C), pH (3.5, 4.0, 5.0, 6.2, and 7.0), and cadmium concentration (0, 2, 10, and 100 mg/l). The spore germination and the viabilities of different mycelial fragments were found to reach their maxima at different values of the ecological factors studied. This finding suggests that the vegetative and asexual types of reproduction of microscopic fungi may have different ecological optima.     

过氧化氢对培养心肌细胞损伤作用的研究

氧化应激时产生大量的自由基,造成心肌细胞的损伤.过氧化氢(H₂O₂)是有机体氧化代谢产物,同时是一种活性氧.应用不同浓度的H₂O₂,分别于不同作用时间,动态观察其对心肌细胞的损伤作用.从实验结果看到,低浓度的H₂O₂（＜0.1 mmol/L）作用2 h,使心肌细胞产生早期的生物化学的改变,如MDA产生堆积和细胞周期时相改变（G1期细胞增加,G2期细胞减少）,此时心肌酶基本无泄漏,心肌细胞的死亡率很低,HE形态学观察基本无改变;随着H₂O₂浓度的增加（1～5 mmol/L）和作用时间的延长,进一步诱导细胞损伤加剧,LDH释放和MDA积累明显升高,细胞死亡率也明显增加,已具有统计学意义.同时可观察到其病理形态学的坏死性改变;当10 mmol/L H₂O₂作用时,细胞大量死亡,形态学可见细胞极度收缩、脱落,形成大面积的细胞脱失区.因此,H₂O₂作为一种活性氧自由基,依其浓度和作用时间不同可造成不同程度的心肌细胞的损伤.辣根过氧化物酶作为一种自由基清除剂,可明显减少H₂O₂活性氧自由基对心肌细胞的损伤作用.     

Spatial Peculiarities in the Colonization of the Plant Rhizoplane by Microscopic Fungi

Spatial peculiarities in the colonization of the tomato, cucumber, and barley rhizoplanes by microscopic fungi were studied. The apical zone of roots was colonized with a limited number of Rstrategists (the order Mucorales, Fusariumsp., Aspergillus niger, and Mycelia sterilia). The fungal population of the root hairs and the basal zone of roots was 2- to 3-fold denser due to the prevalence of Kstrategists. Fusaria, Fusarium oxysporumin particular, colonized roots in earlier terms than the genera Trichoderma, Penicillium, Gliocladium, and others. The F. oxysporumpopulation was at a maximum in the rhizoplane zone nearest the root tip.     

The Distribution of Microscopic Fungi along Moscow Roads

The distribution of microscopic fungi in soils and surface air along some Moscow roads was studied from 1994 through 2000 at several distances (0, 5, 10, and 20 m) from the roads. Soil fungal complexes in roadside zones with different levels of pollution from automobile engines were found to differ in their composition, species structure, and biomorphology. Relatively far from the roads, the content of fungal mycelium diminished, while that of fungal spores increased. Close to the roads, fungal complexes in soil and surface air were dominated by dark melanin-containing fungi. The microscopic fungal complexes of soil and surface air along the roadsides were similar but differed in the relative abundance of some species.     

Interaction of Hydrogen Peroxide with Ribulose-1,5-bisphosphate Carboxylase/Oxygenase from Rice

The properties of rice-derived ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) in different concentrations of hydrogen peroxide (H2O2) solutions have been studied. The results indicate that at low H2O2 concentrations (0.2-10 mM), the properties of rubisco (e.g., carboxylase activities, structure, and susceptibility to heat denaturation) change slightly. However, at higher H2O2 concentrations (10-200 mM), rubisco undergoes an unfolding process, including the loss of secondary and tertiary structure, forming extended hydrophobic interface, and leading to cross-links between large subunits. High concentrations of H2O2 can also result in an increase in susceptibility of rubisco to heat denaturation. Further pre-treatments with or without reductive reagents to rubisco show that the disulfide bonds in rubisco help to protect the enzyme from damage by H2O2 as well as other reactive oxygen species.     

不同施氮水平下丛枝菌根真菌对藜麦生长和根系生理特征的影响

采用盆栽实验,以藜麦品种‘亿隆1号’为实验材料,探究在不同施氮量(纯氮用分别为0、0.2、0.4和0.6g/kg)接种2种丛枝菌根真菌(AM)即摩西球囊霉(Gm)和扭形球囊霉(Gt)对藜麦及其根系生长指标以及生理指标的影响,为提高氮肥利用率提供理论依据。结果表明:(1)在0.4g/kg施氮量下,接种Gm藜麦根系侵染率和菌根依赖性最大。(2)同一接种处理下,藜麦株高、基径、叶面积、地上部生物量、总根长等根系生长指标,以及根系抗氧化酶活性均随施氮量的增加呈先增加后减小的趋势;与未接种处理相比,接种AM真菌后上述各指标均显著增加,均在0.4g/kg施氮量下达到最大值,且接种Gm的增幅大于接种Gt。(3)同一接种处理下,藜麦根系MDA含量、可溶性糖含量和脯氨酸含量随施氮量的增加均呈先减小后增加的趋势;与未接种处理相比,接种AM真菌后藜麦根系MDA含量显著减小,而其根系可溶性糖含量和脯氨酸含量增加,且接种Gm根系MDA含量降幅以及可溶性糖含量和脯氨酸含量的增幅显著大于接种Gt。研究表明,适量施氮可显著增加藜麦根系摩西球囊霉和扭形球囊霉的侵染率及其菌根依赖性指数,促进藜麦地上部及根系的生长,同时增加其根系抗氧化酶活性和渗透调节物质的积累,减少了体内有害物质的积累,并以摩西球囊霉配合施氮0.4g/kg效果最佳。     

Analysis of Hydrogen Peroxide in an Aqueous Extract of Cigarette Smoke and Effect of pH on the Yield

An analysis of hydrogen peroxide in an aqueous extract of cigarette smoke, which contains many redox-active compounds, requires a method with high selectivity. An aqueous extract of the particulate phase of cigarette smoke was analyzed by HPLC with an electrochemical detector (ECD). Samples were prepared by collecting the particulate phase of the cigarette smoke on a glass fiber filter and extracting it with a phosphate buffer. The obtained solution was purified by using a Waters Oasis MCX cation-exchange cartridge, and then analyzed by an HPLC-ECD system with a Shodex KS-801 mixed-mode resin column. Pre-injecting hydrogen peroxide at a high concentration into the HPLC instrument stabilized the analytical results. The recovery of hydrogen peroxide by using an extract of the particulate phase of the cigarette smoke was more than 80%. An increase in the amount of hydrogen peroxide was observed during extraction with the phosphate buffer at higher pH values. In contrast, extraction with phosphoric acid did not increase the amount of hydrogen peroxide during extraction.     

不同生境具有抗肿瘤活性的海洋真菌筛选

目的:为了测定海口沿海海域不同生境的海洋真菌抗肿瘤状况。方法:我们从海口西海岸沿线、南渡江入海口处以及演丰红树林三个不同生境分离到162株海洋真菌,通过MTT比色法测定海洋真菌代谢产物对黑色素瘤B16的抑制活性。结果:其中75.93%的海洋真菌代谢产物对B16细胞增殖有不同的抑制作用,来自西海岸沿线生境的真菌有77.36%具有抑制B16生长作用,来自入海口生境的真菌为77.27%,来自红树林的真菌为70.58%,并且不同生境的真菌代谢物的细胞毒性强弱也有明显的区别。结论:不同生境的真菌具有不同的抗肿瘤作用,筛选具有某种活性海洋真菌菌株时,可以选择容易产某种活性成分的目的生境。     

Screening for Ergot Alkaloid Producers among Microscopic Fungi by Means of the Polymerase Chain Reaction

The potential of the polymerase chain reaction for the detection of ergot alkaloid producers among microscopic fungi of the generaPenicilliumand Clavicepswas evaluated. Twenty-three strains of various species of fungi with a previously studied capacity for alkaloid production were used. The internal fragment of the gene encoding 4-dimethylallyltryptophan synthase, the enzyme catalyzing the first step in the biosynthesis of ergot alkaloids, was amplified using degenerate primers. This approach revealed an about 1.2-kb specific DNA fragment in micromycetes synthesizing ergot alkaloids with complete tetracyclic ergoline system. Microorganisms that produce alkaloids with modified C or D ergoline rings, as well as -cyclopiazonic acid, did not yield the PCR fragment of the expected size. This fragment was also not found in fungi incapable of ergot alkaloid production.     

Peroxidation of Linoleic Acid Induced by Interaction with Haemoglobin and Hydrogen Peroxide

Peroxidation of linoleic acid was found lo be induced by interaction with haemoglobin and hydrogen peroxide. The peroxidation of linoleic acid induced by this interaction was inhibited by desferrioxamine. ethylenediaminetetraacetic acid or α-tocopherol. and poorly by catalase. However. it was accelerated by ascorbic acid.     

外源H2O2处理对唐古特白刺愈伤组织脯氨酸代谢的影响

以唐古特白刺（Nitraria tangutorum Bobr.）愈伤组织为材料,研究外源H₂O₂（2和10 μmol·L^-1）处理下其脯氨酸含量及相关代谢酶活性的变化,试图从细胞水平揭示H₂O₂影响脯氨酸代谢的生理机制。结果显示,2和10 μmol·L^-1 H₂O₂处理24 h使唐古特白刺愈伤组织脯氨酸含量分别变为对照的112%和92%,而处理72 h后,脯氨酸含量增加为对照的141%和119%;与对照相比,外源H₂O₂处理诱导愈伤组织脯氨酸脱氢酶活性降低,而谷氨酸激酶活性升高,但鸟氨酸转氨酶活性无显著变化;此外,H₂O₂处理使唐古特白刺愈伤组织内源性H₂O₂含量升高。结果表明,外源H₂O₂诱导了唐古特白刺愈伤组织H₂O₂含量的增高和脯氨酸的积累,且H₂O₂处理下脯氨酸脱氢酶活性的降低及谷氨酸激酶的升高与愈伤组织脯氨酸的积累有关。     

The Myoglobin-Derived Radical Formed on Reaction of Metmyoglobin with Hydrogen Peroxide is not a Tyrosine Peroxyl Radical

The reductive cleavage of hydrogen peroxide by metmyoglobin produces a protein-derived, motionally restricted free radical detectable by the spin-trapping EPR technique. In order to determine if the detected radical was a peroxyl radical, ¹⁷O₂ and anoxic conditions were employed. The EPR spectra of the metmyoglobin-derived radical adduct detected under nitrogen incubations were identical to those of the oxygenated systems in both intensity and form. No additional hyperfme couplings were detected in the EPR spectrum when 1702 was used. Both of these results indicate that a peroxyl radical derived from molecular oxygen was not found. Additionally, spectra of spin trapped metmyoglobin from four different mammalian species were examined. No significant difference was seen among any of the species, even though one of the species, sperm whale, has one more tyrosine residue than the others.     

野生型油菜黄单胞菌的过氧化氢释放特性

采用外源过氧化氢和油菜组织处理油菜黄单胞菌野生型(XpW)和烷基过氧化物还原酶亚基C突变型(Xp1),检测了各体系中过氧化氢的释放情况,并测定了油菜黄单胞菌野生型的最大过氧化氢耐受浓度范围,以明确植物-病原菌互作过程中是否具有病原细菌源的过氧化氢产生.结果显示:(1)过氧化氢处理3.5 h后,对外源过氧化氢的清除率相对于0.5 h时XpW为100%,Xp1为-26%,说明野生型对培养体系中过氧化氢的清除率高于突变型;油菜组织处理后,体系中产生和积累的过氧化氢情况是:XpW为3.5 h时比0.5 h时高2.105倍,Xp1为3.5 h时比0.5 h时低25.2%,说明野生型培养体系中产生和积累的过氧化氢量高于突变型.(2)野生型的最大过氧化氢耐受浓度范围为1.715 08×105～2.450 11×105 μmol/L,远远高于油菜组织处理XpW菌液时体系中最大检测到的过氧化氢浓度,说明本实验中油菜组织处理XpW菌液过程中产生的过氧化氢的浓度不能够杀灭XpW.由此推测,油菜组织处理体系中野生型油菜黄单胞菌能够产生部分的过氧化氢,其过氧化氢的产生与烷基过氧化物还原酶亚基C相关,支持植物-病原细菌相互作用过程中可能有细菌源的过氧化氢产生的观点.     

家蚕胚胎发育中过氧化氢的代谢(英文)

过氧化氢（Ｈ_２Ｏ_２）是生物体内主要的活性氧来源之一。在超氧化物歧化酶（ＳＯＤ）、过氧化氢酶（ＣＡＴ）等的催化作用下,Ｈ_２Ｏ_２。被降解,释放出活性氧。所以,生物个体发育过程中体内Ｈ_２Ｏ_２、ＳＯＤ和ＣＡＴ含量的变化反映着Ｈ_２Ｏ_２的代谢水平。另外,家蚕是蚕卵滞育昆虫,实验设计考虑到了滞育前后可能会有的差别。取产后１０分钟内的卵为供试材料。采用即时浸酸法解除卵滞育。采用比色法和氧电极法测定并比较家蚕胚胎滞育形成与解除过程中过氧化氢的代谢。结果表明：（１）受精初期（０～４ｈ）,Ｈ_２Ｏ_２含量在２．５ｈ时达到峰值（Ｆｉｇ．１）,相应地ＳＯＤ活性处于较高水平,而ＣＡＴ活性处于最低水平（Ｆｉｇ．２）;（２）胚胎发育过程中（即时浸酸解除滞育）,Ｈ_２Ｏ_２含量除１６８～２１６ｈ处于低水平外均显著高于滞育卵（Ｆｉｇ．３）,ＳＯＤ活性分别在７２ｈ、１６８ｈ,形成小大两峰,后期显著高于滞育卵（Ｆｉｇ．４）,而ＣＡＴ活性７２－１９２ｈ保持平稳,随后急剧上升,前期显著低于滞育卵,后期相反（Ｆｉｇ．５）;（３）滞育形成过程中Ｈ_２Ｏ_２水平变化平缓（Ｆｉｇ．６）,ＳＯＤ活性前期剧烈变动,但后期保持平稳（Ｆｉｇ．７）,ＣＡＴ活性逐步升     

The Beneficial Effect of Ginsenoside Rg1 on Schwann Cells Subjected to Hydrogen Peroxide Induced Oxidative Injury

Ginsenoside Rg1 (GRg1) has been considered to have therapeutic potential in promoting peripheral nerve regeneration and functional recovery after sciatic nerve injuries. However, the mechanism underlying the beneficial effect of GRg1 on peripheral nerve regeneration is currently unclear. The possible effect of GRg1 on Schwann cells (SCs), which were subjected to oxidative injury after nerve injury, might contribute to the beneficial effect of GRg1 on nerve regeneration. The present study was designed to investigate the potential beneficial effect of GRg1 on SCs exposed to oxidative injury. The oxidative injury to SCs was induced by hydrogen peroxide. The effect of GRg1 (50 μM) on SCs exposed to oxidative injury was measured by the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT) in SCs. The cell number and cell viability of SCs were evaluated through fluorescence observation and MTT assay. The apoptosis of SCs induced by oxidative injury was evaluated by an apoptosis assay. The expression and secretion of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were evaluated using RT-PCR, Western blotting, and an ELISA method. We found that GRg1 significantly up-regulated the level of SOD, GSH and CAT, and decreased the level of MDA in SCs treated with hydrogen peroxide. In addition, GRg1 has been shown to be able to inhibit the proapoptotic effect of hydrogen peroxide, as well as inhibit the detrimental effect of hydrogen peroxide on cell number and cell viability. Furthermore, GRg1 also increased the mRNA levels, protein levels and secretion of NGF and BDNF in SCs after incubation of hydrogen peroxide. Further study showed that preincubation with H89 (a PKA inhibitor) significantly inhibited the effects induced by hydrogen peroxide, indicating that the PKA pathway might be involved in the antioxidant effect and neurotrophic factors (NTFs) promoting effect of GRg1. In addition, a short-term in vivo study was performed to confirm and validate the antioxidant effect and nerve regeneration-promoting effect of GRg1 in a sciatic crush injury model in rats. We found that GRg1 significantly increased SOD, CAT and GSH, decreased MDA, as well as promoted nerve regeneration after crush injury. In conclusion, the present study showed that GRg1 is capable of helping SCs recover from the oxidative insult induced by hydrogen peroxide, which might account, at least in part, for the beneficial effect of GRg1 on nerve regeneration.     

外源H2O2对盐胁迫下小麦幼苗生理指标的影响

以‘郑麦-004’小麦幼苗为供试材料,采用Hoagland营养液培养方法,通过添加H2O2的清除剂过氧化氢酶(CAT)和抗坏血酸(ASA),研究0.05μmol/L外源H2O2处理对150mmol/L NaCl胁迫下小麦幼苗生长和抗氧化系统活性的影响,探讨低浓度外源H2O2对盐胁迫下小麦幼苗伤害的防护作用及其生理机制。结果显示:外源H2O2能缓解盐胁迫对小麦幼苗生长的抑制效应,降低丙二醛(MDA)含量和超氧自由基(O2.-)的产生速率,使小麦幼苗的株高、根长和干重均显著增加,并能提高超氧化物歧化酶(SOD)、过氧化物酶(POD)、CAT、抗坏血酸氧化酶(APX)等保护酶活性和抗氧化物质谷胱甘肽(GSH)的含量;而H2O2清除剂(CAT和AsA)能够逆转外源H2O2对盐胁迫下小麦幼苗生长的促进作用。研究表明,低浓度外源H2O2处理能促进小麦幼苗中的酶类和非酶类抗氧化剂的产生,减少脂质过氧化物的含量,提高小麦幼苗的耐盐性。     

过氧化氢对内皮祖细胞凋亡相关蛋白表达的影响

目的:比较不同浓度过氧化氢(hydrogen peroxide,H2O2)对人外周血来源的内皮祖细胞(endothelial progenitor cells,EPCs)生存能力的改变及其对凋亡相关蛋白表达的影响。方法:采用密度梯度离心法和差速贴壁法从人外周静脉血中分离培养内皮祖细胞。选取传代后第3代EPCs作为研究对象,以终浓度分别为50μmol/L、100μmol/L、150μmol/L、200μmol/L、300μmol/L和400μmol/L的过氧化氢处理内皮祖细胞12 h,同时设立正常处理对照组。CCK-8法检测各组内皮祖细胞生存能力的差异;Western blot分析各组内皮祖细胞中凋亡相关蛋白Bax、Bcl-2和p53的蛋白表达情况。结果:与对照组相比,在浓度为50μmol/L、100μmol/L和150μmol/L过氧化氢处理组中细胞存活能力逐渐增强,促凋亡蛋白Bax、p53随之下调,抗凋亡蛋白Bcl-2则显著上调;在浓度为200μmol/L、300μmol/L和400μmol/L过氧化氢处理组中细胞生存能力相对于正常对照组逐渐减弱,促凋亡蛋白Bax、p53表达水平逐渐增加,抗凋亡蛋白Bcl-2表达水平下降。结论:过氧化氢对内皮祖细胞存活能力和凋亡相关蛋白Bax、Bcl-2、p53表达的影响均呈双相性变化。     

The Use of Hydrogen Peroxide for Closing Disulfide Bridges in Peptides

The use of hydrogen peroxide for the formation of disulfide bridges was studied in 15 peptides of various lengths and structures. The oxidation of peptide thiols by hydrogen peroxide was shown to proceed under mild conditions without noticeable side reactions of Trp, Tyr, and Met residues. Yields of the corresponding cyclic disulfides were high and mostly exceeded those obtained with other oxidative agents, in particular, iodine. It was established that the use of hydrogen peroxide in organic medium also provided sufficiently high yields when large-scale syntheses of oxytocin and octreotide (up to 10 g) were carried out.     

衰老叶片和叶绿体中H_2O_2的累积与膜脂过氧化的关系

在自然衰老和ABA处理的叶片和叶绿体中活性氧H_2O_2均比对照明显增高。外加H_2O_2刺激水稻叶绿体膜脂过氧化作用。叶绿体的丙二醛含量随H_2O_2浓度、光照时间、光照强度及叶绿体完整性而变化。AsA、GSH、SOD、甘露醇和过氧化氢酶对外源H_2O_2引起的膜脂过氧化有缓解作用,Fe~(2+)有刺激作用。而H_2O_2对叶绿体过氧化损伤主要是转化为OH之故。     

磷脂酶D对ParA1诱导的烟草的细胞死亡和过氧化氢及莨菪亭积累的影响

利用药理学方法,研究了烟草寄生疫霉(Phytophthora parasitica)分泌的蛋白激发子ParA1诱导烟草悬浮细胞后,磷脂酶D对ParA1诱导的过敏细胞死亡和其它防卫反应的影响.用100nmol/LParA1处理烟草悬浮细胞后能够诱导细胞死亡、过氧化氢和莨菪亭的积累.磷脂酶D抑制剂正丁醇能够抑制ParA1诱导的这些防卫反应,仲丁醇所起的抑制作用比正丁醇小,正丁醇和仲丁醇产生的抑制效果具有浓度依赖效应.而叔丁醇不能抑制ParA1诱导的这些反应.结果表明,磷脂酶D参与了ParA1诱导烟草悬浮细胞的信号传导过程.