千里光抗菌作用的数量性状分析

应用倍比稀释法检测18份千里光（Senecio scandens Buch-Ham）水煎剂对7种细菌的抗菌效果。最低抑菌浓度（minimal inhibitory concentration,MIC）检测结果表明,千里光对金黄色葡萄球菌的抗菌作用最强,对铜绿假单胞菌的抗菌效果最差。比较不同细菌的MIC值发现,温和气单胞菌共检测出4个不同的MIC值,金黄色葡萄球菌、铜绿假单胞菌、大肠埃希菌、甲型副伤寒杆菌、福氏痢疾杆菌和迟钝爱德华菌的MIC值为5个,迟钝爱德华菌的MIC值最多,表现出6个MIC梯度值。本研究结果提示千里光个体有效抗菌组分的多样性,也意味着千里光抗菌药理学性状为多基因控制的数量性状。     

Quantitative analysis by HPLC-MS2 of the pyrrolizidine alkaloid adonifoline in Senecio scandens

A quantitative method using HPLC-MS(2) has been developed for the determination of adonifoline, one of the retronecine-type hepatotoxic pyrrolizidine alkaloids in Senecio scandens Buch.-Ham. ex D. Don., a traditional Chinese herb. Using an orthogonal design test, a simple and rapid sample extraction method was developed. HPLC analysis was conducted using a C(18) column as stationary phase and a mixture of acetonitrile and aqueous formic acid as mobile phase. Good linearity for adonifoline was found in the concentration range 0.12-4.18 microg/mL, and the HPLC-MS/MS method was shown to be appropriate, in terms of sensitivity, precision and reproducibility. The quantities of adonifoline in extracts of 18 plant samples from different collection sources and from different parts (flowers, leaves, thick stems, slim stems and roots) of S. scandens were determined using the newly developed HPLC/MS(2) analysis.     

千里光β-微管蛋白基因结构与功能的生物信息学分析

β-微管蛋白是影响细胞新陈代谢和行使功能的重要结构物质,研究β-微管蛋白基因的序列信息对揭示其蛋白结构与功能具有重要指导意义。从千里光全长cDNA文库中分离得到β-微管蛋白基因,并采用生物信息学软件进行序列分析。结果显示,该基因长度为1750 bp,编码的蛋白质长度为448个氨基酸,与柚子β-微管蛋白的同源性最高,达96%;其蛋白质分子量为50.01 kD,理论等电点为4.83。β-微管蛋白二级结构主要组成为无规则卷曲结构和α螺旋结构;结构域分析发现该蛋白具有两个保守结构域;三级结构预测为相对稳固的类球形结构;信号肽分析将该蛋白主要定位于细胞质、过氧化物酶体、线粒体基质等亚细胞器位置。将该基因序列上传至GenBank所获得的登录号为KF887495。本实验结果为千里光β-微管蛋白的作用机制揭示和应用研究提供了基础数据,也为植物β-微管蛋白基因的分子研究提供了理论依据及基础资料。     

千里光合子胚和胚乳形成及其早期发育的细胞学特征(英文稿)

千里光（Senecio scandens Buch.-Ham. ex D. Don）是传统中草药, 抗菌功效显著。本研究从细胞学角度对千里光合子胚和胚乳的形成与发育进行观察研究。结果显示,结构和功能迥异的基细胞和顶细胞源自细胞质不均一分布的合子所致,推测合子的极性与胚囊的极性和生殖核分裂为“二态”精细胞有关;基细胞在合子胚胎“球型期”末期出现分化,早期胚胎的组织分化始于“三角期”,可辨别的结构差异直到“鱼雷期”才出现。此外,胚乳形成遵循无细胞壁核化模型。本研究对千里光细胞分化、组织分化和结构差异各发育阶段特征的观察结果,不仅可为深入分析胚胎发育过程功能基因的时空表达提供依据,也为相关近缘物种的系统植物学研究提供参考资料。     

千里光合子胚和胚乳形成及其早期发育的细胞学特征（英文）

千里光(Senecio scandens Buch.-Ham. ex D. Don)是传统中草药,抗菌功效显著。本研究从细胞学角度对千里光合子胚和胚乳的形成与发育进行观察研究。结果显示,结构和功能迥异的基细胞和顶细胞源自细胞质不均一分布的合子所致,推测合子的极性与胚囊的极性和生殖核分裂为二态精细胞有关;基细胞在合子胚胎球型期末期出现分化,早期胚胎的组织分化始于三角期,可辨别的结构差异直到鱼雷期才出现。此外,胚乳形成遵循无细胞壁核化模型。本研究对千里光细胞分化、组织分化和结构差异各发育阶段特征的观察结果,不仅可为深入分析胚胎发育过程功能基因的时空表达提供依据,也为相关近缘物种的系统植物学研究提供参考资料。     

千里光配子体发育、配子形成与双受精的细胞学特征

千里光（Senecio scandens Buch.-Ham.ex D.Don）是具有良好开发前景的传统抗菌中草药。为了探讨该物种有性生殖的细胞学机制,实现在物种的遗传育种过程中的指导作用,本研究从细胞学角度观察了千里光配子体发育、配子形成和双受精作用。结果表明,在生殖核分裂为精细胞的过程中,其位置和形态呈现差异,表现为"二态"精细胞;此外,雌配子体的形成符合孢子发育模式,成熟胚囊的形态结构为卵形或梨形,成熟的卵细胞和极核位于珠孔端。根据上述结果可推断,合子在随后二分裂时表现为"基细胞-顶细胞"极性,可能与"二态"精细胞导致的合子细胞质不均一有关。此外,从植物分类学角度,千里光的"二态"精细胞,胚囊极性和合子极性可成为菊科近缘植物分类的细胞学依据。     

千里光肌动蛋白基因（Actin）的生物信息学及功能分析

肌动蛋白（Actin）是广泛存在于高等植物中的组成型表达蛋白质,与细胞分裂、细胞运动、细胞信号转导等功能密切相关。为明确肌动蛋白性质与功能的关系,本研究从千里光全长cDNA文库中分离得到Actin基因。序列分析结果表明：该基因长度为1 481 bp,编码360个氨基酸残基的多肽,与甘草Actin基因编码的氨基酸序列（GenBank登录号：ABW71681.1）的同源性最高,达96%;预测蛋白质的分子量为40.02 kDa,理论等电点为5.85;结构分析发现,螺旋结构和无规则卷曲构成Actin二级结构的主要组分;三级结构预测发现,Actin具有4个结构域;蛋白系统发生树发现,与甘草和鹰嘴豆的亲缘关系较近。本研究认为,高等植物Actin可能参与基因的转录调控,其氨基酸突变位点未对功能结构域产生影响。     

Effects of low selenium diets on antioxidant status and MPTP toxicity in mice

To investigate the role of chronic oxidative stress in MPTP neurotoxicity, C57BL mice were maintained 6–8 weeks on diets deficient in nutrients essential to cellular antioxidant defenses, selenium (Se) and alpha-tocopherol (vit E), and the effects on tissue antioxidant status and MPTP toxicity were evaluated relative to controls on supplemented diets. Activities of the major antioxidant enzymes, glutathione peroxidase (GPx), catalase, and superoxide dismutase, and levels of malondialdehyde as a marker for oxidative stress, were measured in brain, lung, liver and blood. Caudate depletion of dopamine and its metabolites served as a measure of MPTP neurotoxicity. For mice on the Se deficient diet, levels of the selenoenzyme GPx decreased from 50% in brain to 90% in blood. No compensatory changes in the activities of the other antioxidant enzymes were observed and addition of vit E to the diet did not alter antioxidant enzyme activities or malondialdehyde levels. In animals not treated with MPTP, the Se deficient diet significantly increased malondialdehyde only in liver. No protective effect of the antioxidant supplements against caudate depletion of dopamine and its metabolites was observed. However, malondialdehyde levels were increased in the brains of MPTP treated mice on the low Se diets, suggesting the possibility of secondary oxidative damage to tissues accompanying the destruction of substantia nigra neurons by MPTP.     

Selenium uptake, translocation and speciation in wheat supplied with selenate or selenite

Selenite can be a dominant form of selenium (Se) in aerobic soils; however, unlike selenate, the mechanism of selenite uptake by plants remains unclear. Uptake, translocation and Se speciation in wheat (Triticum aestivum) supplied with selenate or selenite, or both, were investigated in hydroponic experiments. The kinetics of selenite influx was determined in short-term (30 min) experiments. Selenium speciation in the water-extractable fraction of roots and shoots was determined by HPLC-ICPMS. Plants absorbed similar amounts of Se within 1 d when supplied with selenite or selenate. Selenate and selenite uptake were enhanced in sulphur-starved and phosphorus-starved plants, respectively. Phosphate markedly increased K(m) of the selenite influx. Selenate and selenite uptake were both metabolically dependent. Selenite was rapidly converted to organic forms in roots, with limited translocation to shoots. Selenomethionine, selenomethionine Se-oxide, Se-methyl-selenocysteine and several other unidentified Se species were detected in the root extracts and xylem sap from selenite-treated plants. Selenate was highly mobile in xylem transport, but little was assimilated to organic forms in 1 d. The presence of selenite decreased selenate uptake and xylem transport. Selenite uptake is an active process likely mediated, at least partly, by phosphate transporters. Selenite and selenate differ greatly in the ease of assimilation and xylem transport.     

Oxygen toxicity and superoxide dismutase as an antioxidant in physiological stress

Although oxygen is vital for all aerobic life forms, excessive levels of oxygen free radical production can lead to potentially lethal oxidative reactions. The role of superoxide dismutase is examined as an integral part of the defence against oxidative injury resulting from various physiological stresses.     

Promotion of lipid oxidation by selenate and selenite and indicators of lipid peroxidation in the rat

The AIN-93 reformulation of the AIN-76A rodent diet includes a change in selenium supplement from sodium selenite to sodium selenate to reduce dietary lipid peroxidation. A change to selenate as the standard form of Se in rat diets would render results from previous work using selenite less relevant for comparison with studies using the AIN-93 formulation. To critically examine the rationale for the AIN-93 recommendation, we prepared Torula yeast basal diets patterned as closely as possible after the AIN-93 formulation and supplemented with 0, 0.15 (adequate), or 2.0 (high) mg selenium/kg diet as sodium selenite or sodium selenate. Livers isolated from male Sprague-Dawley rats fed these diets for 15 wk showed no differences in thiobarbituric acid-reactive substances or lipid hydroperoxides measured with the ferrous oxidation in xylenol orange method. Lipids isolated from samples of high-selenate and high-selenite diets showed no differences in conjugated dienes. The addition of selenate or selenite to soybean oil did not result in an altered Oil Stability Index. These results demonstrate that selenate is not less likely than selenite to cause oxidation of other dietary components. Benefits of selenate over selenite in the diets of rodents remain to be demonstrated. Results included in this paper were presented at the meeting of Experimental Biology 98, San Francisco, CA, April 18–22, 1998, and published in abstract form (Moak, M. A., Johnson, B. L., & Christensen, M. J. [1998] On the AIN-93G recommendation for selenium. FASEB J. 12, A824).     

Pyrrolizidine alkaloids in and on the leaf surface of Senecio jacobaea L

This is the first study showing that alkaloids are present on the leaf surface of plants. A concentration of 30-230 pmol/cm2 pyrrolizidine alkaloids (PA's) was detected in 8 different samples taken from Senecio jacobaea. PA concentration on the leaves was marginally correlated with PA concentration of the total leaf tissues. The PA spectrum on the leaf differed from the PA spectrum of the total leaf.     

Histochemistry evaluation of the oxidative stress and the antioxidant status in Cu-supplemented cattle

The aim of this paper is to evaluate at a histopathological level the effect of the most commonly used copper (Cu) supplementation (15 mg/kg dry matter (DM)) in the liver of intensively reared beef cattle. This was done by a histochemistry evaluation of (i) the antioxidant capacity in the liver – by the determination of metallothioneins (MT) and superoxide dismutase (SOD) expression – as well as (ii) the possible induction of oxidative damage – by the determination of inducible nitric oxide synthase (iNOS), nitrotyrosine (NITT), malondialdehyde (MDA) and 8-oxoguanine (8-oxo) – that (iii) could increase apoptotic cell death – determined by cytochrome-c (cyto-c), caspase 1 (casp1) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Liver samples from Cu-supplemented (15 mg Cu sulphate/kg DM, n = 5) and non-supplemented calves (n = 5) that form part of other experiments to evaluate Cu status were collected at slaughter and processed for immunohistochemistry and TUNEL. MT expression was diffuse and SOD showed slight changes although without statistical significance. iNOS and NITT positive (+) cells significantly increased, mainly around the central veins in the animals from the Cu-supplemented group, whereas no differences were appreciated for the rest of the oxidative stress and apoptosis markers. Under the conditions of this study, which are the conditions of the cattle raised in intensive systems in NW Spain and also many European countries, routinely Cu supplementation increased the risk of the animals to undergo subclinical Cu toxicity, with no significant changes in the Cu storage capacity and the antioxidant defensive system evaluated by MT and SOD expression, but with a significant and important increase of oxidative damage measured by iNOS and NITT. The results of this study indicated that iNOS and NITT could be used as early markers of initial pathological changes in the liver caused by Cu supplementation in cattle, although more studies in cattle under different levels of Cu supplementation are needed.     

Brain antioxidant systems in human methamphetamine users

Animal data suggest that the widely abused psychostimulant methamphetamine can damage brain dopamine neurones by causing dopamine-dependent oxidative stress; however, the relevance to human methamphetamine users is unclear. We measured levels of key antioxidant defences [reduced (GSH) and oxidized (GSSG) glutathione, six major GSH system enzymes, copper-zinc superoxide dismutase (CuZnSOD), uric acid] that are often altered after exposure to oxidative stress, in autopsied brain of human methamphetamine users and matched controls. Changes in the total (n = 20) methamphetamine group were limited to the dopamine-rich caudate (the striatal subdivision with the most severe dopamine loss) in which only activity of CuZnSOD (+ 14%) and GSSG levels (+ 58%) were changed. In the six methamphetamine users with severe (- 72 to - 97%) caudate dopamine loss, caudate CuZnSOD activity (+ 20%) and uric acid levels (+ 63%) were increased with a trend for decreased (- 35%) GSH concentration. Our data suggest that brain levels of many antioxidant systems are preserved in methamphetamine users and that GSH depletion, commonly observed during severe oxidative stress, might occur only with severe dopamine loss. Increased CuZnSOD and uric acid might reflect compensatory responses to oxidative stress. Future studies are necessary to establish whether these changes are associated with oxidative brain damage in human methamphetamine users.     

Lectotypification of the Bertoloni's names in the genus Senecio L. (Asteraceae)

Original material of the four Senecio taxa described by A. Bertoloni has been examined, and the typification of their names is discussed. A specimen from the Monti Herbarium (kept in BOLO) and iconographies from Bonanni and Bertoloni are designated as lectotypes, whereas another specimen from the Monti Herbarium is selected as neotype. The nomenclature of the names Senecio erucifolius L., Senecio tenuifolius Jacq., Senecio delphinifolius Vahl and Senecio rupestris Waldst. & Kit. is also analysed. The names S. crinitus Bertol. and S. laciniatus Bertol. belong to S. delphinifolius [now Jacobaea delphinifolia (Vahl) Pelser & Veldkamp] and S. rupestris [now Senecio squalidus subsp. rupestris (Waldst. & Kit.) Greuter], respectively, whereas S. erraticus Bertol. and S. praealtus Bertol. are accepted as separate taxa as Jacobaea erratica (Bertol.) Fourr. and Jacobaea erucifolia subsp. praealta (Bertol.) Greuter & B.Nord., respectively.     

Assessment of oxidant/antioxidant status in saliva of cell phone users

Hazardous health effects resulting from exposure to radiofrequency electromagnetic radiation (RF-EMR) emitted from cell phones have been reported in the literature. However, the cellular and molecular targets of RF-EMR are still controversial. The aim of this study was to examine the oxidant/antioxidant status in saliva of cell phone users. Saliva samples collected before using a cell phone as well as at the end of 15 and 30?min calls were tested for two commonly used oxidative stress biomarkers: malondialdehyde (MDA) and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-Oxo-dG). The 8-oxo-dG levels were determined by enzyme-linked immunosorbent (ELISA) competitive assay, while the MDA levels were measured using the OxiSelect MDA adduct ELISA Kit. The antioxidant capacity of the saliva was evaluated using the oxygen radical absorption capacity (ORAC) and the hydroxyl radical averting capacity (HORAC) assays according to the manufacture instructions. The mean 8-oxo-dG and the Bradford protein concentrations (ng/ml and mg/ml, respectively) peaked at 15?min. The levels of HORAC, ORAC and MDA progressively increased with time and reached maximum at 30?min. However, there was no significant effect of talking time on the levels of 8-OxodG and MDA. Similarly, there was no statistically significant effect of talking time on the oxygen and hydroxyl radicals averting capacities, (ORAC) and (HORAC), respectively. These findings suggest that there is no relationship between exposure to radio frequency radiation (RFR) and changes in the salivary oxidant/antioxidant profile.