Two New C19-Diterpenoid Alkaloids from Delphinium shawurense

Shawurenine C ( 1a ) and D ( 1b ), a new pair of regioisomeric C₁₉-diterpenoid alkaloids, and five known C₁₉-diterpenoid alkaloids ( 2 – 6 ) were isolated from the aerial part of Delphinium shawurense W. T. Wang. The chemical structures of new compounds were established based on spectroscopic analyses: HR-ESI-MS, and 1D, 2D NMR spectroscopic data. The anti-inflammatory and cytotoxic activities of these diterpenoid alkaloids were also evaluated.     

Transmembrane kinase 1-mediated auxin signal regulates membrane-associated clathrin in Arabidopsis roots

Clathrin-mediated endocytosis (CME) is the major endocytic pathway in eukaryotic cells that directly regulates abundance of plasma membrane proteins. Clathrin triskelia are composed of clathrin heavy chains (CHCs) and light chains (CLCs), and the phytohormone auxin differentially regulates membrane-associated CLCs and CHCs, modulating the endocytosis and therefore the distribution of auxin efflux transporter PIN-FORMED2 (PIN2). However, the molecular mechanisms by which auxin regulates clathrin are still poorly understood. Transmembrane kinase (TMKs) family proteins are considered to contribute to auxin signaling and plant development; it remains unclear whether they are involved in PIN transport by CME. We assessed TMKs involvement in the regulation of clathrin by auxin, using genetic, pharmacological, and cytological approaches including live-cell imaging and immunofluorescence. In tmk1 mutant seedlings, auxin failed to rapidly regulate abundance of both CHC and CLC and to inhibit PIN2 endocytosis, leading to an impaired asymmetric distribution of PIN2 and therefore auxin. Furthermore, TMK3 and TMK4 were shown not to be involved in regulation of clathrin by auxin. In summary, TMK1 is essential for auxin-regulated clathrin recruitment and CME. TMK1 therefore plays a critical role in the establishment of an asymmetric distribution of PIN2 and an auxin gradient during root gravitropism.     

Nature and metabolism of a thymus cyst studied by histochemistry and autoradiography

Summary A thymus cyst was discovered in connection with autoradiographical studies on sulphur metabolism of the rat. The coincidence must be considered unique and has motivated amplifying histochemical investigations.The cyst-content showed a strong positive PAS-reaction and after toluidine blue -metachromasia, which along with the incorporation of S³⁵ makes the presence of acid mucopolysaccharides likely. A strong blackening was noticed on the autoradiogram over the greater part of the cyst. This infers that the content has been metabolized here, in contradistinction to the centre with inactive colloid.     

小麦Kr基因在小麦与玉米或鸭茅状摩擦禾杂交中的失活

用３７个小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ）品种（系）为母本,分别与黑麦（Ｓｅｃａｌｅｃｅｒｅａｌｅ）、球茎大麦（Ｈｏｒｄｅｕｍｂｕｌｂｏｓｕｍ）、玉米（Ｚｅａｍａｙｓ）和鸭茅状摩擦禾（Ｔｒｉｐｓａｃｕｍｄａｃｔｙｌｏｉｄｅｓ）杂交,比较其亲和性,小麦和玉米或鸭茅状摩擦禾杂交比小麦与黑麦或球茎大麦杂交的亲和性显著提高。携带着显性Ｋｒ１和Ｋｒ２基因的小麦品种Ｈｏｐｅ与黑麦杂交,不能形成胚,而与玉米及鸭茅状摩擦禾杂交时,成胚率分别达１６．００％和３２．５０％。表明控制小麦与黑麦及球茎大麦杂交亲和性的Ｋｒ基因系统在小麦与玉米及小麦与鸭茅状摩擦禾属间杂交中失活。讨论了还存在有其它控制小麦属间杂交亲和性的遗传调控系统的可能性。     

Clonal organization of populations of Asarum europaeum and Maianthemum bifolium in contrasting woodland habitats

Populations of two rhizomatous species, Asarum europaeum (asarabacca) and Maianthemum bifolium (May lily), were examined in two, and four forest habitats respectively, in the Roztocze National Park (south-eastern Poland). May lily populations were studied in habitats: the Carpathian beechwood, upland mixed fir forest, subboreal moist mixed coniferous forest and bog-alder forest. Asarabacca was studied in two habitats: beechwood and Scots pine community (an 80-year-old plantation). In both the species studied intra- and inter-populational differences of the size of genets in terms of above- and below-ground parts of individuals as well as the biomass and area occupied were observed. In May lily populations the greatest mean number of shoots per genet was found in the fir forest (11.62±3.29), a value almost twice as great as that in the moist coniferous forest and nearly three times greater than in the bog-alder forest. Total rhizome length was also the greatest in the fir forest (351.9±98.7 cm) followed by moist coniferous forest, beechwood and alder forest habitats. In all populations of May lily a greater part of total dry weight biomass is in below-ground organs. The greatest biomass value of a genet was found in the fir forest (4.275 g), the smallest in the bog-alder forest (0.110 g). All populations differed significantly in terms of leaf area, leaf length (with the exception of fir forest and beechwood habitats where the values were the greatest), and leaf width (excluding moist coniferous and bog-alder forests which had the smallest values). In the case of asarabacca, both the mean number of ramets per genet (3.36±0.45 vs. 2.49±0.20) and total rhizome length (40.3±6.4 cm vs. 21.1±1.8 cm) were greater in the beechwood habitat than in the pine community. In the first population genets had 3–5 times greater the total biomass of those from the pine community. Only genets of the latter had proportionately more dry weight biomass in above-ground parts. It seems to be correlated with greater rhizome dieback and disintegration of genets into smaller units. Both populations were significantly different in terms of all examined parameters of leaves. Genets of both the species studied were found to have their own structure of developmental phases that often differed for shoots and rhizomes.     

黄瓜幼苗的冷锻炼与低温引起的光抑制

黄瓜幼苗的冷锻炼与低温引起的光抑制李晓萍,陈贻竹,李平,郭俊彦（中国科学院华南植物研究所,广州５１０６５０）关键词：低温引起的光抑制,荧光猝灭,冷锻炼,黄瓜幼苗低温使植物利用光能的能力降低从而引起或加剧光抑制（ｈａｓ等１９８３）。在光抑制中常以叶绿素...     

四膜虫(Tetrahymena shanghaiensis)大核核仁与去膜大核能诱导非细胞体系核重建

外源DNA或染色质在非洲爪蟾卵提取物中可以诱导细胞核样结构的重建。重建核除不具有核仁样结构外,在其它形态结构上与真核细胞核十分相似。前人的工作表明在重建核中具有核仁前体结构。但可能是由于缺少活性核仁组织者的缘故,这些核仁前体不能相互融合形成新生核仁。那么活性核仁组织者在重建核中是否能发挥其功能呢?为了研究这一问题,我们提取纯化了四膜虫的大核与大核的周边核仁。进一步去除大核的核被膜,并将去除核被膜的大核与大核核仁分别加入非洲爪赡卵非细胞体系中。通过电镜超薄切片观察,我们发现无论是与大核染色质相连的周边核仁还是分离纯化的核仁结构在非洲爪赡卵非细胞体系中都不能保持其原有结构特征,而是发生了典型核重建变化,并且在诱导形成的重建核中也看不到核仁样结构。这些结果说明具有活性的核仁组织者在加入非洲爪蟾卵提取物后既不能继续保持其原有的RNA转录功能也不能诱导新的核仁的出现。     

Investigations of peptide hydration using NMR and molecular dynamics simulations: A study of effects of water on the conformation and dynamics of antamanide

Summary The influence of water binding on the conformational dynamics of the cyclic decapeptide antamanide dissolved in the model lipophilic environment chloroform is investigated by NMR relaxation measurements. The water-peptide complex has a lifetime of 35 s at 250 K, which is longer than typical lifetimes of water-peptide complexes reported in aqueous solution. In addition, there is a rapid intracomplex mobility that probably involves librational motions of the bound water or water molecules hopping between different binding sites. Water binding restricts the flexibility of antamanide. The experimental findings are compared with GROMOS molecular dynamics simulations of antamanide with up to eight bound water molecules. Within the simulation time of 600 ps, no water molecule leaves the complex. Additionally, the simulations show a reduced flexibility for the complex in comparison with uncomplexed antamanide. Thus, there is a qualitative agreement between the experimental NMR results and the computer simulations.     

大鼠肾小球微循环活体观察实验研究

结扎大鼠一侧输尿管,复制肾盂积水模型。在冷光源－光导纤维－导光棒的透射照明下,通过显微电视系统,成功地观察到完整肾脏皮质表层肾小球及其周围血管微血流动态的清晰图像。正常肾小球呈树状分布,密集、大小均匀。高倍镜下可清楚辨认入球及出球小动脉,其血细胞流态为直线状。并发现肾小球有交替开放现象。