Comparative enzymology of the adenosine triphosphate sulphurylases from leaf tissue of selenium-accumulator and non-accumulator plants

1. ATP sulphurylases were partially purified (20-40-fold) from leaf tissue of Astragalus bisulcatus, Astragalus racemosus (selenium-accumulator species) and Astragalus hamosus and Astragalus sinicus (non-accumulator species). Activity was measured by sulphate-dependent PP(i)-ATP exchange. The enzymes were separated from pyrophosphatase and adenosine triphosphatase activities. The properties of the Astragalus ATP sulphurylases were similar to the spinach enzyme. 2. The ATP sulphurylases from both selenium-accumulator and non-accumulator species catalysed selenate-dependent PP(i)-ATP exchange; selenate competed with sulphate. The ratio of V(selenate)/V(sulphate) and K(m)(selenate)/K(m)(sulphate) was approximately the same for the enzyme from each species. 3. Sulphate-dependent PP(i)-ATP exchange was inhibited by ADP, chlorate and nitrate. The kinetics of the inhibition for each enzyme were consistent with an ordered reaction mechanism, in which ATP is the first substrate to react with the enzyme and PP(i) is the first product released. 4. Synthesis of adenosine 5'-[(35)S]sulphatophosphate from [(35)S]sulphate was demonstrated by coupling the Astragalus ATP sulphurylases with Mg(2+)-dependent pyrophosphatase; the reaction was inhibited by selenate. An analogous reaction using [(75)Se]selenate as substrate could not be demonstrated.     

乌兰布和沙漠东北缘三种豆科绿肥植物生物量和养分含量及其对土壤肥力的影响

土壤肥力是限制乌兰布和沙漠东北缘沿黄灌区建立高产绿洲的主要因子之一。在内蒙古自治区磴口县试验地种植3种绿肥植物,比较它们改良土壤的效果。结果表明,1～2年生紫花苜蓿的总生物量干重为最高,而沙打旺则因其抗风沙能力强,地上部分生长较其它两种植物为好,由于植株中水分含量较高,其生物量的鲜重在三者中是最高的。2年生绿肥植物总生物量干重和养分含量的测定结果则显示,全氮和全磷含量的变化趋势为沙打旺〉紫花苜蓿〉草木樨,而全钾含量则为紫花苜蓿〉草木樨〉沙打旺;从3种植物对土壤改良效果来看,改良作用为沙打旺〉紫花苜蓿〉草木樨。与两种常用的绿肥作物相比,沙打旺因其对风沙较强的抗性而具有较高的改良土壤能力,因此在同类型的沙漠绿洲开发初期可以作为改良土壤的首选植物。     

Isolation and identification of two isomeric glutamylselenocystathionines from the seeds of Astragalus pectinatus

Two glutamylselenocystathionines have been isolated from the seeds of Astragalus pectinatus. These have been identified as 2-γ-glutamylamino-4-(2-amino-2-carboxyethylselenyl) butyric acid and 2-amino-4-(2-γ-glutamylamino-2-carboxyethylselenyl) butyric acid. The evidence for the natural occurrence of the corresponding glutamylcystathionines is also presented.     

Drought stress-induced methyl jasmonate accumulation promotes calycosin-7-O-β-d-glucoside production in Astragalus membranaceus adventitious roots

Plant Cell, Tissue and Organ Culture (PCTOC) - Calycosin-7-O-β-d-glucoside (CG) is a major isoflavone in Astragalus membranaceus and has multiple pharmacological activities. Astragalus...     

丛枝菌根真菌与根瘤菌互作及类黄酮对互作效果的影响

研究了中华根瘤菌与AM真菌互作或加入适量的类黄酮(150nmol·L^-1和1．5μmol·L^-1)对紫云英的生物量、结瘤数、AM真菌的侵染率、菌丝ALP和SDH酶活性的影响．结果表明,与对照组[0、AMF、Rh]相比,Rh+AMF组紫云英的生物量、结瘤数、AM真菌侵染率和菌丝酶活都有显著差异;与对照组及Rh+AMF组相比,类黄酮处理组紫云英的生物量、结瘤数、AM真菌侵染率和菌丝酶活差异更加显著,但不同类黄酮间(apigenin和hesperitin),或同一种类黄酮不同浓度处理问(150nmol·L^-1和1．5umol·L^-1)差异不明显,说明AM真菌与根瘤菌互作对紫云英的结瘤固氮、AM真菌的侵染和菌丝的生长都有促进作用．当Rh+AMF组加入适量的类黄酮时。这种促进作用更加显著．     

Effect of nitrogen concentration,source, and phosphate concentration on accumulation of biomass and calycosin-7-O-β-D-glucoside in Astragalus membranaceus adventitious roots

In Vitro Cellular & Developmental Biology - Plant - Calycosin-7-O-β-D-glucoside (CG), a methoxylated isoflavonoid in Astragalus membranaceus Fisch. (Bunge), has a wide range of biological...     

RAPD and FAME analyses of Astragalus species growing in eastern Anatolia region of Turkey

Fatty acid (FAs) and RAPD profiles were used to examine phenotypic and genetic relationships between eight Astragalus species including Astragalus maximus Willd. var. maximus, Astragalus coadunatus Hub. Mor. & Chamb., Astragalus kurdicus Boiss. var. kurdicus, Astragalus lagurus Willd, Astragalus christianus L., Astragalus cicer L., Astragalus atrocarpus Champ & Matthews and Astragalus onobrychioides Bieb., which were wildly growing in eastern Anatolia region of Turkey. All of the eight Astragalus species tested in this study were separated based on the presence and composition of 45 different FAs. Four of the Astragalus species including A. coadunatus, A. lagurus, A. christianus, and A. atrocarpus were rich in terms of FA contents containing at least 22–31 different FAs. The relative proportions of two fatty acids, 16:0, and 18:1:ω8c were higher in these four Astragalus species. The remaining species have limited number of FAs with unique FAMEs profiles. Six of the 10 decamer primers examined were selected to find out genetic polymorphism in Astragalus species. A total of 98 polymorphic bands were observed, ranging in size from 250 bp to 3000 bp. The RAPD results suggested that A. atrocarpus, A. onobrychioides and A. kurdicus are closely related and completely different from the other species. Six genetically distinct groups were found among the species of Astragalus. High genetic variations among Astragalus species growing wildly in eastern Anatolia region of Turkey may imply the differences in their origins. The results in the present study suggested that both RAPD and FA analyses are useful for differentiation of Astragalus species.     

Flavonoid glycosides and saponins from Astragalus shikokianus

A new flavonol glycoside, kaempferol 3-O-alpha-L-rhamnopyranosyl -(1-->6)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-galactopyranosyl-7-O-a lpha-L-rhamnopyranoside, named astrasikokioside I, was isolated from aerial part of Astragalus shikokianus, together with two flavonol glycosides, kaempferol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl-7-O-alpha-L- rhamnopyranoside, robinin, and three triterpenoid glycosides, soyasaponin I, sophoraflavoside II and robinioside E.     

黄芪多糖对暴露于苯、甲醛环境中小鼠脾脏的保护作用

目的探讨黄芪多糖对暴露于苯、甲醛环境中小鼠脾脏的保护作用。方法将40只雄性小鼠随机分成4组,即对照组、苯甲醛染毒组（苯：5 g/m^3,甲醛：50 mg/m^3）、苯甲醛染毒黄芪多糖低剂量保护组[黄芪多糖：10 mg/（kg.d）,苯：5 g/m^3,甲醛：50 mg/m^3]、苯甲醛染毒黄芪多糖高剂量保护组[黄芪多糖：20 mg/（kg.d）,苯：5 g/m^3,甲醛：50 mg/m^3]。采用静式吸入染毒,每天2 h,连续30 d,并同时采用饮水的方式给予黄芪多糖保护。末次染毒24 h内,处死小鼠,对小鼠脾中谷胱甘肽（GSH）含量及谷胱甘肽过氧化物酶（GSH-PX）活性进行测定和分析。结果苯、甲醛染毒黄芪多糖保护各组脾组织中GSH含量和GSH-PX活性均高于苯、甲醛染毒组,均有统计学意义（P〈0.01）而与对照组的差异无统计学意义（P〉0.05）,苯、甲醛染毒黄芪多糖保护组高剂量组脾组织中GSH-PX活性高于低剂量组,差异有统计学意义（P〈0.01）。结论黄芪多糖对暴露于苯、甲醛环境中小鼠脾脏具有保护作用,且对脾中GSH含量的作用有随剂量增加而增大的趋势,对脾中GSH-PX活性的作用随剂量增加而增大。     

The sterols of Astragalus species from Iran: GLC separation and quantification

This paper presents the content and composition of free sterols in a number of Astragalus species from Iran. Free sterols of roots and seeds were analysed quantitatively and qualitatively by gas-liquid chromatography. Four major 3-beta-hydroxysterols (cholesterol, campesterol, stigmasterol and beta-sitosterol) were identified in roots of 18 species and in seeds of five species of Astragalus. beta-Sitosterol was the main free sterol in both roots and seeds. The cholesterol content in seeds was higher than that in roots. Trace amounts of cholesterol were detected in roots of only four species. beta-Sitosterol accounted for 34.4-69.2 and 76.8-81.8% of the total lipid content in roots and seeds, respectively. The beta-sitosterol content in roots and seeds of Astragalus species varied from 6.3 to 35.7 and 93.3 to 164.5mg/100g dry weight, respectively. Total free sterol content in seeds varied from 112.09 to 204.04mg/100g dry weight, significantly higher than those in roots (7.5 to 43.4mg/100g dry weight). The chemotaxonomic values of free sterols and total lipid profiles of some of the representative species are discussed.     

枸杞多糖与黄芪多糖抑菌活性的研究*

目的:研究黄芪多糖和枸杞多糖的抑菌活性并探讨不同pH值对其抑菌活性的影响。方法:采用滤纸片扩散法,分析不同浓度黄芪多糖和枸杞多糖在不同pH值下对几种常见细茵和霉菌(大肠杆菌、沙门氏菌、金黄色葡萄球菌、黑曲霉、产黄青霉)的抑制效果。结果:对于细菌,枸杞多糖8mg/mL时出现抑菌圈,而黄芪多糖0.02 mg/mL时效果最佳;对于霉菌,随着枸杞多糖浓度的增大,抑菌圈的直径增大,而黄芪多糖0.02 mg/mL时效果最佳;当枸杞多糖和黄芪多糖在pH6的条件下,二者抑菌活性均最强。结论:枸杞多糖和黄芪多糖对细菌、霉菌都有一定的抑制效果,pH值可影响枸杞多糖和黄芪多糖的抑菌效果。     

Chemical diversity and biological activities of the saponins isolated from Astragalus genus: focus on Astragaloside IV

Phytochemistry Reviews - Astragalus is a cosmopolitan genus characterised by a large number of species with an exceptional rate of diversification. Many of these species are used since ancient...     

Molecular phylogeny of selected Old World Astragalus (Fabaceae): incongruence among chloroplast trnL-F, ndhF and nuclear ribosomal DNA ITS sequences

This study reports maximum parsimony and Bayesian phylogenetic analyses of selected Old World Astragalus using two chloroplast fragments including trnL-F and ndhF and the nuclear ribosomal internal transcribed spacer (nrDNA ITS). A total of 52 taxa including 34 euploid Old World and New World Astragalus , one aneuploid species from the Neo-Astragalus clade as a representative and 14 other Astragalean taxa, plus Cheseneya astragalina and two species of Caragana as outgroups were analyzed for both trnL-F and nrDNA ITS regions. ndhF was analyzed in 30 taxa and the same number for the combination of these three datasets were examined. In general, the trnL-F dataset and the ndhF and nrDNA ITS datasets generated more or less the same clades within Astragalus . However, in the trnL-F and ndhF phylogenies, Astragalus species are not gathered in a single clade, the so-called Astragalus s.s., as indicated by the nrDNA ITS tree. Visual inspection of these three phylogenies revealed that they were inconsistent regarding the position and relationships of Astragalus hemsleyi , A. ophiocarpus , A. annularis–A. epiglottis / Astragalus pelecinus, A. echinatus and A. arizonicus . Incongruence length difference test suggested that the trnL-F , ndhF and nrDNA ITS datasets were incongruent. In spite of this, phylogenetic analyses of the combined datasets as one unit or as three partitions generated trees that were topologically similar as a mix of the cpDNA and the nrDNA ITS trees. However, the combined dataset provided more resolved and statistically supported clades. The recently described A. memoriosus appeared closely related to A. stocksii (both from sect. Caraganella ) based on both trnL-F and nrDNA ITS sequences.     

Astragalus mario-sousae (Fabaceae: Galegeae), a new species from northeastern Mexico

Astragalus mario-sousae is described from the central part of state of Nuevo León, Mexico. It differs fromAstragalus esperanzae by its habit, peduncles, pedicels, and fruits.

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Resumen   Astragalus mario-sousae (Fabaceae: Galegeae), a new species from northeastern Mexico. Brittonia 57: 314–319. 2005.—Astragalus mario-sousae es propuesta como especie nueva. Se conoce solo de la porción central del estado mexicano de Nuevo León. Se presentan una descripción e ilustración. Difiere deAstragalus esperanzae por su hábito erecto, pedúnculos, pedicelos y frutos más cortos.

     

Determination of astragalosides in the roots of Astragalus spp. using liquid chromatography tandem atmospheric pressure chemical ionization mass spectrometry

A high-performance liquid chromatography tandem atmospheric pressure chemical ionization mass spectrometry method (HPLC-APCI-MS) has been developed for the characterization of astragalosides in the extracts of the roots of Astragalus spp. The [M - H](-) ions of astragalosides could be clearly observed in selected ion monitoring mode and APCI-MS-MS was used to further identify the structures of the astragalosides. Twelve astragalosides in the extracts of Radix Astragali obtained from Shandong in China were separated and identified. Using this method, astragalosides could be clearly identified and the profiles of these astragalosides could also be used to distinguish Astragalus spp. from different habitat regions.     

黄芩甙对铜绿假单胞菌R质粒的消除作用

测定黄芩甙对铜绿假单胞菌R质粒的消除作用 ;以携带R质粒的铜绿假单胞菌株PA16为靶细菌 ,以黄芩甙作为R质粒消除剂 ,进行R质粒体内外消除试验 ;体外消除实验结果表明 ,黄芩甙对PA16的消除率为 5 .1% ,明显高于空白对照组 ,也高于EB对照组的结果 ;体内R质粒消除率为 12 .0 % ,明显高于对照组 ;黄芩甙在体内外对铜绿假单胞菌R质粒具有较强的消除作用 ,为其实际应用提供实验依据。     

Propagation of Rare Plants from Historic Seed Collections: Implications for Species Restoration and Herbarium Management

Herbaria are potentially important repositories of living seeds that could be useful for recovery of rare plant species. To examine this capacity, we tested seed germination of rare milkweed (Asclepias) and milkvetch (Astragalus) species representing different collection dates and different herbaria. These groups have contrasting seed characteristics, with greater potential for longevity in the nonpermeable hard-coated milkvetch seeds. Twelve-year-old Asclepias lanuginosa seeds failed to germinate. However, we achieved 45% germination from three-year-old Asclepias meadii seeds, but germination dropped to 0% after ages of four to five years. Astragalus neglectus seeds germinated from 97-, 48-, and 28-year-old herbarium specimens, and Astragalus tennesseensis seeds germinated from a four-year-old collection. Seedlings produced from these experiments were incorporated into ex situ garden populations for recovery or restoration of rare species populations. Different herbarium pest control techniques may have significant bearing on the viability of seeds stored on herbarium specimens. Microwaving can cause precipitous loss of seed viability, while deep-freezing appears to allow some seeds to remain viable. Potentially live seeds of rare species should be stored under conditions that enhance their long-term viability.     

Symbiosis of Astragalus cicer with its microsymbionts: partial nodC gene sequence, host plant specificity, and root nodule structure

Astragalus cicer (cicer milkvetch) nodule bacteria were investigated for host plant specificity and partial nodC gene sequences, whilst their native host was studied for the microscopic structure of root nodules. The strains under investigation formed nodules not only on the original host but also on Astragalus glycyphyllos, Astragalus sinicus, Lotus corniculatus, and Phaseolus vulgaris. The nodules induced on the cicer milkvetch were classified as indeterminate and characterized by apical, persistent meristem, a large bacteroid region with infected and uninfected cells, and elongated bacteroids singly located inside peribacteroid membranes. By comparison of the partial nodC gene sequences of a representative strain of astragali rhizobia to those contained in the GenBank database, a close symbiotic relationship of A. cicer microsymbionts to Rhizobium sp. (Oxytropis) was found.     

云南黄芪属(豆科)新资料

A new variety Astragalus englerianus Ulbr.var.gingdongensis Z.G.Qian,var.nov.andnew synonyms Astragalus saccatocarpus K.T.Fu,Astragalus naignichus Y.H.Xu et Q.R.Liu,As-tragalus voburus Y.H.Xu et Q.R.Liu are reported in this paper.