促进铁皮石斛试管苗移栽成活的研究

目的有效加速铁皮石斛试管苗的人工繁殖.方法:对铁皮石斛试管苗在移植时期进行不同基质(有无伴生植被)、根长和营养液浓度等方面的研究.结果:最适宜的基质是1/3泥炭 1/3锯末 1/3珍珠岩,覆以苔藓类伴生植被可大大提高移栽成活率.组培苗根长在0.5～1.0 cm时是移植的最佳时期,移植半个月后施放1/2倍营养液为最好.结论:对铁皮石斛中药的GAP种植具有重要的指导意义.     

Chemical constituents from Bupleurum chinese and their chemotaxonomic significance

A phytochemical investigation of the roots of Bupleurum chinese DC. led to the isolation of eighteen compounds, including three chromones (1–3), seven flavonoids (4–10), one dihydrochalcone (11), two phenylpropanoid glycosides (12–13), one lignan (14), three sterols (15–17) and one stilbenoid (18). Their structures were elucidated on the basis of NMR spectroscopic analysis and comparison with literature data. Compounds 6–7, 11–14 and 18 were firstly reported from the genus Bupleurum and the family Apiaceae. Moreover, the chemotaxonomic value of the isolates was also discussed.     

Wall appositions induced by ionophore A 23187, CaCl2, LaCl3, and nifedipine in characean cells

Summary The formation of wall appositions (plugs) by ionophore A 23187, CaCl₂, LaCl₃, and nifedipine was studied in mature internodal cells of characeaen algae. CaCl₂ at concentrations above 10^–2M induces thick fibrillar plugs without callose inNitella flexilis. InChara corallina andNitella flexilis ionophore A 23187 (1.25×10^–5 to 5×10^–5M) and LaCl₃ (7.5×10^–5 to 2.5×10^–4M) cause flat appositions which contain callose and have a more granular structure. Plug formation by ionophore A 23187, CaCl₂, and LaCl₃ is pH-dependent and occurs beneath the alkaline regions of the cell. Nifedipine (10^–4 to 10^–5M) induces plugs inNitella flexilis after previous injury. These callose-containing wall appositions consist of a heterogeneous granular core which is covered by a fibrillar layer. The results of this work are compared with previous studies on wound wall formation and chlortetracycline (CTC)-induced plug formation which reveal that abundant coated vesicles occur only when a thick fibrillar wall layer is formed. Neither LaCl₃ nor nifedipine inhibit the formation of CaCl₂- or CTC-plugs. The unusual effects of these substances, which normally act as Ca²⁺ antagonists and therefore should prevent and not induce plug formation, are discussed. It is suggested that La³⁺ mimicks the effects of calcium and that nifedipine binding to the Ca²⁺ channels is altered in the alkaline regions of characean internodes and allows an influx of Ca²⁺.Abbreviations AFW artificial fresh water - CTC chlortetracycline - DCMU dichlorphenyldimethylurea - DMSO dimethylsulfoxide - EGTA ethyleneglycoltetraacetic acid - MES 2-(N-morpholino) ethanesulfonic acid - HEPES N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid - TAPS N-tris[hydroxymethyl]methyl-3-aminopropanesulfonic acid     

Wound-induced and naturally occurring regenerative differentiation of xylem in Zea mays L.

The regenerative differentiation of xylem, both around a wound in the stem and at the root junction was studied in seedlings of maize. The regeneration of vessels around a wound was very small, being limited to the very young internodes and sharply declining basipetally. There were more regenerative vessel elements and they differentiated faster above the wound than below it. The regenerative vessel elements around the wound were characterized by helical or annular pattern of secondary wall thickenings. Wounding also resulted in the development of additional vascular anastomoses in the leaf immediately above the wound, and in differentiation of discontinuous vessels in adjacent bundles. Regenerative vessel elements were very common where the adventitious roots connected with the stem internodes, and exhibited pitted or reticulated secondary wall thickenings.     

Mechanism of rapid suppression of cell expansion in cucumber hypocotyls after blue-light irradiation

Rapid suppression of hypocotyl elongation by blue light in cucumber (Cucumis sativus L.) was studied to examine possible hydraulic and wall changes responsible for diminished growth. Cell-sap osmotic pressure, measured by vaporpressure osmometry, was not decreased by blue light; turgor pressure, measured by the pressureprobe technique, remained constant during the growth inhibition; and stem hydraulic conductance, measured by dynamic and static methods, was likewise unaffected by blue light. Wall yielding properties were assessed by the pressure-block technique for in-vivo stress relaxation. Blue light reduced the initial rate of relaxation by 77%, but had little effect on the final amount of relaxation. The results demonstrate that blue irradiation acts to decrease the wall yielding coefficient, but not the yield threshold. Stress-strain (Instron) analysis showed that irradiation of the seedlings had little effect on the mechanical extensibilities of the isolated wall. The results indicate that blue light can reduce cell-wall loosening without affecting bulk viscoelastic properties, and indicate a chemorheological mechanism of cell-wall expansion.Abbreviations and symbols BL blue light - wall yield coefficient - Y wall yield threshold - P turgor pressure - L hydraulic conductance - g radial water-potential gradient supporting cell expansion - osmotic pressure - P_i initial chamber pressure needed to stop growth - P_f final chamber pressure needed to stop growth     

德国柏林墙遗址地区公共空间的保护与规划研究

柏林墙是柏林近代史上重要的一段政治事件遗迹与历史见证。从1990年6月至今,柏林政府对柏林墙遗址地区进行了不同层面的保护和开发。梳理了柏林墙与柏林城市发展的关系,从政府工作、遗址构筑物与户外公共空间3个方面,研究了柏林墙遗址地区的保护与规划内容,认为针对柏林墙遗址地区,德国政府及人民对历史予以足够的尊重,以政府为主导的多维度、持续性的规划工作对遗址地区起到了重要的保护作用。灵活多样、高品质的公共空间营造方式与丰富的纪念性活动,使得衰败的地区得以激活和复兴,为中国遗址地区保护与规划设计提供借鉴。     

What is needed to make low-density lipoprotein transport in human aorta computational models suitable to explore links to atherosclerosis? Impact of initial and inflow boundary conditions

Personalized computational hemodynamics (CH) is a promising tool to clarify/predict the link between low density lipoproteins (LDL) transport in aorta, disturbed shear and atherogenesis. However, CH uses simplifying assumptions that represent sources of uncertainty. In particular, modelling blood-side to wall LDL transfer is challenged by the cumbersomeness of protocols needed to obtain reliable LDL concentration profile estimations. This paucity of data is limiting the establishment of rigorous CH protocols able to balance the trade-offs among the variety of in vivo data to be acquired, and the accuracy required by biological/clinical applications.In this study, we analyze the impact of LDL concentration initialization (initial conditions, ICs) and inflow boundary conditions (BCs) on CH models of LDL blood-to-wall transfer in aorta. Technically, in an image-based model of human aorta, two different inflow BCs are generated imposing subject-specific inflow 3D PC-MRI measured or idealized (flat) velocity profiles. For each simulated BC, four different ICs for LDL concentration are applied, imposing as IC the LDL distribution resulting from steady-state simulations with average conditions, or constant LDL concentration values.Based on CH results, we conclude that: (1) the imposition of realistic 3D velocity profiles as inflow BC reduces the uncertainty affecting the representation of LDL transfer; (2) different LDL concentration ICs lead to markedly different patterns of LDL transfer.Given that it is not possible to verify in vivo the proper LDL concentration initialization to be applied, we suggest to carefully set and unambiguously declare the imposed BCs and LDL concentration IC when modelling LDL transfer in aorta, in order to obtain reproducible and ultimately comparable results among different laboratories.     

Involvement of transglutaminase in the formation of covalent cross-links in the cell wall ofCandida albicans

Activity of the enzyme glutaminyl-peptide-γ-glutamylyl-transferase (EC 2.3.2.13; transglutaminase), which forms the interpeptidic cross-link N^∈-(γ-glutamic)-lysine, was demonstrated in cell-free extracts obtained from both the yeast like and mycelial forms ofCandida albicans. Higher levels of enzymatic activity were observed in the cell wall fraction, whereas the cytosol contained only trace amounts of activity. Cystamine, a highly specific inhibitor of the enzyme, was used to analyze a possible role of transglutaminase in the organization of the cell wall structure of the fungus. Cystamine delayed protoplast regeneration and inhibited the yeast-to-mycelium transition and the incorporation of proteins into the cell wall. The incorporation of covalently bound high-molecular-weight proteins into the wall was sensitive to cystamine. Proteic epitopes recognized by two monoclonal antibodies, one of which is specific for the mycelial walls of the fungus, were also sensitive to cystamine. These data suggest that transglutaminase may be involved in the formation of covalent bonds between different cell wall proteins during the final assembly of the mature cell wall.     

中国南极长城湾1994年1~2月间海水初级生产初析

 对中国南极长城湾内水体夏季的初级生产力于1994年1～2月间作了估计。发现其初级生产碳量约为0.7998·m-3·d-1。2月份高于1月份。表层、中层和下层相比,下层的日产量仍高。意味着该湾水体处于真光层范围内。水柱上下均有相应的初级生产。水温提高似有利于初级生产。初级生产的粗生产量与叶绿素a(Chl-a)、NH4-N、总N、ΣN/P的变化较为一致。营养盐相当充足。而与NO2-N、PO4-P 较不一致。与异养菌数也相悖。推测异养菌有较强的分解有机质能力和矿化作用活动。     

反相HPLC法测定四种柴胡的柴胡皂式a,c,d含量

1990版《中国药典》规定正品柴胡为北柴胡和红柴胡,而各地实际入药的柴胡种类往往与药典规定不尽相同。因此有必要对目前已供药用的柴胡生药中有效成分进行定量分析,作为评判各种柴胡质量的依据之一。本文应用反相HPLC法测定了9种市售商品柴胡,经鉴定为北柴胡（BupleurumchinenseDC．）、红柴胡（B．scorzonerifoliumWilld．）、空心柴胡（B．longicauleWall．exDC．var．franchetiideBoiss．）和不同产地的小叶黑柴胡（B．smithiiWolffvar．parvifoliumShanetY．Li）,分别测定了其柴胡皂式a,c,d（简记为ssa,ssc,ssd）的含…