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1.
小檗科魁臼亚科的地理分布与系统发育   总被引:6,自引:0,他引:6  
以植物地理学资料为主,综合植物化学,细胞学,形态学及解剖学的等方面的资料,分析了小檗科鬼臼科现代地理分布格局产生的原因及其系统发育的影响,指出:(1)我国鬼臼亚科植物的多样性中心和分布中心,鬼臼亚科植物的现代地理分布格局是由于第三纪以来替代分布和长期隔离的结果;(2)在鬼臼亚科植物中,以山荷叶属最为原始,它通过两方向演化,一是保持其原来的异花授方向演化为足叶草属,另一方向是转向自花授粉,自山茶叶属  相似文献   

2.
侧链含有鬼臼毒素高分子抗癌药物的合成   总被引:4,自引:1,他引:3  
分别用可溶性淀粉,羧甲基纤维素钠和甲壳胺为载体与鬼臼毒素合成了三种侧链含有鬼臼毒素高分子抗癌药物。在pH7.4的缓冲溶液中对鬼臼毒基羰甲基淀粉,鬼臼毒基羰甲基纤维素和鬼臼毒基羰甲基甲壳胺的体外水解释放进行了考查。  相似文献   

3.
离子注入对耐辐射微球菌存活及生物量的影响   总被引:3,自引:0,他引:3  
以耐辐射异常微球菌(D.radiodurans)为试材,研究了离子注入对其存活和生物干重的影响。结果表明,不同能量和不同种类的离子注入D.radiodurans,其存活均表现为先降后升再降的变化,即存活曲线呈现为相似的“马鞍型”,只是在不同种类的离子注入中,注入能量为20keV的原子质量较大的N+离子比H+对其存活和生物干重的影响较大;在不同能量的离子注入中,能量相对较高的30keV的N+离子注入比20keV的影响大。离子注入生物体产生这种不同于其它电离辐射的存活规律,意味着其对生物体的作用机理显著不同于其它电离辐射。  相似文献   

4.
桃儿七(Sinopodophylumhexandrum)是小檗科鬼臼亚科植物,它的花美、叶奇,根和根茎具有较高的药用价值,但资源稀少,亟待保护,已被列入《中国珍稀濒危植物名录》,并被《中国植物红皮书》收录。桃儿七是一种生长在亚高山和高山地区的多年生草...  相似文献   

5.
目的:研究低能氮离子注入对多伞阿魏幼苗生理生化指标的影响。方法:以能量30keV、不同剂量N+离子注入多伞阿魏种子,研究分析不同剂量组多伞阿魏幼苗超氧化物歧化酶(SoD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性变化,以及游离脯氨酸和可溶性蛋白质含量变化。结果:随离子注入剂量增大SOD活性增加、POD和CAT活性逐渐升高,剂量过大时,SOD、POD和CAT活性下降;游离脯氨酸含量逐渐降低,但在6×10^16N+/c秆剂量时含量升高;可溶性蛋白质含量先升高再降低,6×10^16N+,c秆剂量时为最高值。结论:适当剂量N+离子注入可激活保护酶酶活性并促使脯氨酸和可溶性蛋白含量升高。  相似文献   

6.
氮离子注入对棉花花粉形态和生活力及育性的影响   总被引:3,自引:0,他引:3  
本文分析了氮离子注入棉花花粉对其形态,生活力和育性的影响。结果表明:氮离子束对花粉壁有明显的刻蚀作用,并能促进花粉粒间的融合。离子注入导致花粉管生长受抑制;过氧化物酶同工酶活性增强,酶带数目增加;萌发率、花粉管穿过花柱到达胚珠率、结籽率和成铃率均较对照显著降低。离子注入剂量与花粉损伤程度的大小呈正相关。经20×10 ̄(15)N ̄+/cm ̄2剂量处理的花粉,其萌发率降为对照的52.3%;花粉管长度仅为对照的17.1%;而且未获得成熟的种子。文中建议棉花花粉离子束诱变的剂量范围以5×10 ̄(15)N ̄+/cm ̄2-10×10 ̄(15)N ̄+/cm ̄2为宜,并且讨论了离子注入技术在植物外源基因导入和细胞融合等方面的应用。  相似文献   

7.
小檗科的花粉演化   总被引:1,自引:0,他引:1  
以APG III定义的基部真双子叶分支(Basal Eudicots)中毛茛目(Ranunculales)小檗科(Berberidaceae)为研究对象,选取4个DNA片段(rbcL、matK、trnLF和26S rDNA),利用最大似然法构建分子系统树,结合已报道的花粉形态数据,分析了该科16个属的花粉形态。选择花粉分散单位、极性、形状、大小、萌发孔数目、萌发孔位置、外萌发孔形状、覆盖层上元素、覆盖层纹饰和外壁厚度共10个关键性状,采用简约法推断了该科花粉的祖征、共衍征和演化式样。研究表明:单粒、等极、近球形、中等大小是小檗科花粉的祖征。无极、多萌发孔和周面孔是小檗亚科(Berberidoideae)的共衍征,支持其为一个单系。三萌发孔分别为鬼臼亚科(Podophylloideae)、南天竹亚科(Nandinoideae)各自的共衍征;覆盖层上元素不存在是小檗亚科和南天竹亚科的共衍征,将它们与鬼臼亚科区分开来,同时也支持了小檗亚科和南天竹亚科之间的姐妹关系。此外,对一些属花粉形态的演化意义进行了讨论,提出一些特殊的花粉性状可以用来定义某些属,如Bongardia和兰山草属(Ranzania)。  相似文献   

8.
超低能离子注入作物育种的一种重要机制   总被引:17,自引:3,他引:17  
本文通过超低能(110keV)离子注入和同步辐射碳光辐照两种手段处理了小麦种子,经萌发在其根尖细胞中均观察到了多种类型的染色体时变,而且同对照相比,均有明显的微核率与染色体总畸变率。根据理论分析和一些有关的实验证据,超低能离子注入小麦种子,因离子本身射程非常短(<1μm),不可能直接损伤麦皮下面的胚细胞,而由注入离子在作物种子内产生的各种特征X-射线,只要剂量足够,却能达到较深的部位,通过它们的间接作用就会损伤胚细胞造成生物学效应。因此,赵低能离子注入作物种子激发产生的特征X-射线是其诱变育种的一种重要机制.  相似文献   

9.
低能离子束对微生物细胞的刻蚀与损伤研究   总被引:23,自引:0,他引:23  
以耐辐射异常微球菌和大肠杆菌为试材,用显微扫描电镜(SEM)和电子自旋共振(ESR)波谱仪研究了20keV的N^+离子注入对其细胞的作用。结果表明,N^+离子注入对两种微生物既存在着直接作用的刻蚀损伤又存在着能量沉积所产生自由基的间接作用;对细胞的直接刻蚀作用是导致DNA损伤和生物诱变的主要原因,而自由基所引起的主要是DNA以外生物大分子的损伤和细胞的膜脂过氧化。随着注入剂量增大,两种微生物细胞受  相似文献   

10.
小檗科鬼臼亚科的地理分布与系统发育   总被引:19,自引:1,他引:19  
以植物地理学资料为主,综合植物化学、细胞学、形态学及解剖学等方面的资料,分析了小檗科鬼臼亚科现代地理分布格局产生的原因及其对系统发育的影响,指出:①我国是鬼臼亚科植物的多样性中心和分布中心,鬼臼亚科植物的现代地理分布格局是由于第三纪以来替代分布和长期隔离的结果;②在鬼臼亚科植物中,以山荷叶属最为原始,它通过两条方向演化,一是保持其原来的异花授粉方向演化为足叶草属,另一方向是转向自花授粉,自山荷叶属演化为八角莲属,然后再演化为桃儿七属;③桃儿七属与足叶草属不具有直接的亲缘关系,它们在形态上的相似只是平行进化的结果。  相似文献   

11.
High-field asymmetric waveform ion mobility spectrometry (FAIMS) is an atmospheric pressure ion mobility technique that separates gas-phase ions by their behavior in strong and weak electric fields. FAIMS is easily interfaced with electrospray ionization and has been implemented as an additional separation mode between liquid chromatography (LC) and mass spectrometry (MS) in proteomic studies. FAIMS separation is orthogonal to both LC and MS and is used as a means of on-line fractionation to improve the detection of peptides in complex samples. FAIMS improves dynamic range and concomitantly the detection limits of ions by filtering out chemical noise. FAIMS can also be used to remove interfering ion species and to select peptide charge states optimal for identification by tandem MS. Here, the authors review recent developments in LC-FAIMS-MS and its application to MS-based proteomics.  相似文献   

12.
Protein oxidation is thought to contribute to a number of inflammatory diseases, hence the development of sensitive and specific analytical techniques to detect oxidative PTMs (oxPTMs) in biological samples is highly desirable. Precursor ion scanning for fragment ions of oxidized amino acid residues was investigated as a label‐free MS approach to mapping specific oxPTMs in a complex mixture of proteins. Using HOCl‐oxidized lysozyme as a model system, it was found that the immonium ions of oxidized tyrosine and tryptophan formed in MS2 analysis could not be used as diagnostic ions, owing to the occurrence of isobaric fragment ions from unmodified peptides. Using a double quadrupole linear ion trap mass spectrometer, precursor ion scanning was combined with detection of MS3 fragment ions from the immonium ions and collisionally‐activated decomposition peptide sequencing to achieve selectivity for the oxPTMs. For chlorotyrosine, the immonium ion at 170.1 m/z fragmented to yield diagnostic ions at 153.1, 134.1, and 125.1 m/z, and the hydroxytyrosine immonium ion at 152.1 m/z gave diagnostic ions at 135.1 and 107.1 m/z. Selective MS3 fragment ions were also identified for 2‐hydroxytryptophan and 5‐hydroxytryptophan. The method was used successfully to map these oxPTMs in a mixture of nine proteins that had been treated with HOCl, thereby demonstrating its potential for application to complex biological samples.  相似文献   

13.
The primary goal of metabolomic analysis is the unbiased relative quantification of every metabolite in a biological system. A number of different metabolite-profiling techniques must be combined to make this possible. Here we report the separation and analysis of highly polar compounds in a proof of concept study. Compounds were separated and analyzed using hydrophilic interaction liquid chromatography (HILIC) coupled to electrospray ionization (ESI) mass spectrometry. Two types of HILIC microbore columns (Polyhydroxyethyl A and TSK Gel Amide 80) were compared to normal phase silica HPLC columns. The best separations of standards mixtures and plant samples were achieved using the Amide 80 stationary phase. ESI enabled the detection of both positively and negatively charged metabolites, when coupled to a quadrupole ion trap mass spectrometer using continuous polarity switching. By stepwise mass spectrometric fragmentation of the most intense ions, unknown compounds could be identified and then included into a custom mass spectrometric library. This method was used to detect oligosaccharides, glycosides, amino sugars, amino acids, and sugar nucleotides in phloem exudates from petioles of fully expanded Cucurbita maxima leaves. Quantitative analysis was performed using external standards. The detection limit for stachyose was 0.5 ng per injection (Amide 80). The concentration of stachyose in investigated phloem samples was in the range of 1-7 mM depending on the plant.  相似文献   

14.
An 'off-line' high performance liquid chromatography-graphite furnace atomic absorption spectrometry (HPLC-GF-AAS) method using a size exclusion chromatography (SEC) column was developed to investigate heavy metal ions in xylem sap samples of cucumber plants grown in hydroponics containing iron as Fe(III)-ethylenediaminetetraacetate (Fe(III) EDTA), Fe(III) citrate or FeCl3 and exposed to lead, nickel or vanadium contamination. The SEC chromatogram of the samples contained the peak of nitrate ions (in significant concentration approximately 1400 microg/ml) and some small, unidentified compounds with molecular weight lower than 700 Da. The results indicate that Cu and Mn--which were added to the hydroponics as nutrient elements--determined in the collected fractions during the chromatographic runs are transported in the xylem vessels together with small inorganic ions like nitrate ions. In case of nickel other low-molecular weight compounds eluting earlier than the nitrate ions may take part in its transport toward the shoots. Lead could not be detected in the above mentioned fractions. Determination of vanadium in the fractions was not expected since it could not be detected in the sap samples.  相似文献   

15.
Capillary liquid chromatography-mass spectrometry using graphitised carbon stationary phase and ion trap mass spectrometry was shown to be a powerful technique for analysing glycosaminoglycans digested with endoglycosidases. Commonly found disaccharides from heparin/heparan sulphate digests at sub nanomole levels were found to be separated by mass and/or retention time and detected by negative ion electrospray mass spectrometry predominantly as [M-H]- ions using a standard electrospray interface and flow rate between 6-10 microL/min. Graphitised carbon liquid chromatography-fragmentation mass spectrometry provided sequence data of disaccharides and oligosaccharides. Sequence information was obtained from either collision of the [M-H]- ions (low sulphated disaccharides) or of the [M+Na-2H]- ions (highly sulphated disaccharides). This separation and identification method of endoglycosidase digestion and sample preparation using a combination of cation exchange and graphitised carbon, was used to successfully analyse digests of keratan sulphate (keratanase) and heparin (heparinase) standards, and hyaluronic acid (hyaluronidase) from synovial fluid samples.  相似文献   

16.
The present study reports the development of a new 1,8‐naphthalimide‐based fluorescent sensor V for monitoring Cu(II) ions. The sensor exhibited pH independence over a wide pH range 2.52–9.58, and indicated its possible use for monitoring Cu(II) ions in a competitive pH medium. The sensor also showed high selectivity and sensitivity towards the Cu(II) ions over other competitive metal ions in DMSO–HEPES buffer (v/v, 1:1; pH 7.4) with a fluorescence ‘turn off’ mode of 79.79% observed. A Job plot indicated the formation of a 1:1 binding mode of the sensor with Cu(II) ions. The association constant and detection limit were 1.14 × 106 M–1 and 4.67 × 10–8 M, respectively. The fluorescence spectrum of the sensor was quenched due to the powerful paramagnetic nature of the Cu(II) ions. Potential application of this sensor was also demonstrated when determining Cu(II) ion levels in two different water samples.  相似文献   

17.
In order to detect the effect of the surface charge discreteness on the properties at the solid–liquid interface, a molecular dynamics simulation model considering the vibration of wall atoms was used to investigate the performance of ion and water under different charge distributions. Through the comparison between simulation results and the theoretical prediction, it was found that, with the increasing degree of discreteness, much more counterions were attracted to the surface. These ions formed a denser accumulating layer which was located much nearer to the surface and caused charge inversion. The ions in this layer were non-hydrated or partially hydrated. When a voltage was applied across the nanochannel, this dense accumulating layer did not move unlike the ions near the uniformly charged surface. From the water density profiles obtained in nanochannels with different surface charge distributions, the influence of the surface charge discreteness on water distributions could be neglected.  相似文献   

18.
A direct and highly selective method, combining liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS), has been developed for quantifying saccharide surfactants. Saccharide surfactants, such as n-octyl-beta-d-glucopyranoside (NOG), are widely used to solubilize or refold membrane-bound or lipophilic proteins. In the present study, we have developed an LC-MS method to quantify NOG in protein samples. Protein-bound NOG was completely dissociated from proteins by reversed-phase LC, allowing the total amount of saccharide surfactant in protein samples to be quantified by MS. A chemical analog of NOG was used as an internal standard for improving the reproducibility of the method. Linearity was found in the range of 10 microg/mL-1.0 mg/mL NOG concentrations. Seven major surfactant oligomeric ions were detected under the ionization conditions applied and their relative abundance was essentially unchanged over the range of 0.05-1.0 mg/mL NOG concentrations. Consequently, ions with characteristic mass-to-charge ratios could be used for quantification of NOG. Analytical accuracy of the method was examined by determining the amounts of NOG recovered from apolipoprotein A-I and myoglobin samples spiked with NOG.  相似文献   

19.
Atmospheric pressure chemical ionization liquid chromatography–mass spectrometry was used in the identification of triacylglycerol molecular species in lymph samples from rats given either a structured lipid or safflower oil. The structured lipid was MLM-type (M, medium-chain fatty acid; L, long-chain fatty acid) and manufactured from caprylic acid (8:0) and the oil (safflower oil or high-oleic sunflower oil). The triacylglycerol composition of lymph varied significantly between structured triacylglycerols and safflower oil. Diacylglycerol fragment ions were found for all triacylglycerols and we could also observe the ammonium adduct molecular ion [M+NH4]+ for all the triacylglycerols at the selected conditions. Protonated molecular ions were formed from triacylglycerols containing unsaturated fatty acids, and fatty acid fragment ions were also observed in the case of strong fragmentation. The lymph triacylglycerols were identified from their ammonium adduct molecular ions and diacylglycerol fragment ions. In addition to the intact MLM-type structured triacylglycerols, the MLL- and LLL-type triacylglycerols were also identified. The absorption pathway of MLM-type structured triacylglycerols is most likely the same as that of conventional long-chain triacylglycerols, i.e. they were hydrolyzed into 2-monoacylglycerol and medium-chain fatty acids, which were then used for resynthesis of triacylglycerols. The present study thereby also demonstrates the possibility to study the absorption pathway of triacylglycerol via identification of triacylglycerol species in biological samples.  相似文献   

20.
氮离子束对小麦种子不同部位作用的突变效应   总被引:3,自引:0,他引:3  
本文描述了荷能重离子束(^14氮^1 和^14氮^7 )在作物改良上的应用。为了探讨离子束轰击小麦种子不同部位(例如:种皮,种胚和整粒种籽,包括胚乳、胚和种皮)后的不同反应,采用了不同能量的氮离子。轰击不同部位是通过改变离子能量来实现的。在这个研究中,我们选择了三种能量以达到轰击不同部位的目的,它们是超低能区的110keV,低能区的15.7MeV/u和中能区的72MeV/u.根据TRIM 91程序计算,它们在种子内的射程依次为0.44μm,0.61mm和9.6mm。所以,110keV的离子不能贯穿种皮,因为它的厚度72μm,只能极浅层注入种皮而不能触及胚细胞(称这种情况为轰击部位1),15.7MeV/u的离子能够贯穿种皮并注入胚内(厚度约1mm),但不能进入胚乳(称这为轰击部位2),72MeV/u的离子能从种子的胚部到顶部贯穿整个麦粒(麦粒长约7mm)(称这为轰击部位3)。上述三种能量的氮离子辐照了三个品种(定西24、88-12、82-579)的春小麦种子。而后进行了室内实验和大田培育,得到了50%出苗率时的剂量D50,统计了上述三个轰击部位下根尖细胞中的微核率及染色体畸变率,大田中产生了一些新的变异,例如增产(达百分之几十),早熟(五天左右),矮杆(低约20cm),抗(条锈)病,并且显示了轰击不同部位的突变频率与突变谱,还简略地讨论了三种情况的突变机理。  相似文献   

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