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471.
瑞典国家财产委员会拥有骑士岛的所有权与管理权,并计划对该岛上所有的公共空间进行更新和开发,以提高其可达性与吸引力。该项目的核心是找到一种更新和修复岛屿的方法,从而在尊重历史价值的同时满足现代功能需求。对骑士岛南部的改造是岛上公共空间更新的第一部分。设计的关键条件是沿滨水区域创造可以供人步行与停坐的大面积空间,并在保持开放海港氛围的同时,对旧的道路铺装进行管理。设计者设计了一套灵活使用公共空间的综合解决方案,将开放空间与之前的码头一样,沿着水滨的形态进行布局。 相似文献
472.
Jo Ann A. Fujii David Slade Jaime Aguirre-Rascon Keith Redenbaugh 《In vitro cellular & developmental biology. Plant》1992,28(2):73-80
Summary Encapsulated somatic embryos (artificial seeds) and naked (uncoated) somatic embryos of alfalfa (Medicago sativa L.) were planted directly into the field to demonstrate the feasibility of using artificial seeds for direct sowing. Various
row coverings that provided protection for the somatic embryos during conversion (plant formation) in the field and encapsulation
methods were investigated. The highest conversion obtained in the field was 25% when naked somatic embryos were planted under
the protective covering of inverted styrofoam cups. In comparison, 60% conversion was obtained when embryos were planted in
potting mix in a growth chamber. Somatic embryos encapsulated by the thin-coat method converted at 23% under cups in the field
and 40% in potting mix in the growth chamber. Naked somatic embryos had an average of 13 and 9% conversion in the field under
plastic and cloth coverings, respectively, whereas encapsulated embryos converted at 5 and 14%, respectively. Direct-planted
embryos (no row covering) converted at 1% in the field. Successful conversion of coated and naked somatic embryos planted
in the field supports the concept of artificial seeds serving as a substitute for natural seeds. 相似文献
473.
474.
International Journal of Primatology - Electric shock and electrocution affect at least 31 primate species, but studies of how electrical infrastructure affects primate populations are rare. We... 相似文献
475.
Large-scale purification of a Dictyostelium discoideum cell surface glycoprotein, which is anchored in the membrane via a glycosylphosphatidylinositol (GPI) moiety, is described. The purification protocol involved four steps: separation of crude cell membranes by low-speed centrifugation, delipidization of these membranes using acetone, extraction of the membrane proteins using the detergent Octyl beta-D-thioglucopyranoside (OTP), and purification of a specific membrane protein by monoclonal antibody immunoaffinity chromatography. The protein purified, PsA (prespore-specific antigen), is a developmentally regulated membrane glycoprotein found on a subset of cells from the cellular slime mould, D. discoideum. The protocol provides an efficient, economical, and technically simple way to purify GPI proteins in sufficient quantities for structural and functional studies. PsA was recovered at a yield of about 60%; with a purity of 97%, the extraction of 1 x 10(10) cells (1.1 g dry weight) yielded about 0.5 mg PsA glycoprotein. Techniques are described for growing kilogram quantities of D. discoideum cells in stainless steel trays at little cost. D. discoideum has considerable potential as a novel expression system for the production of foreign membrane-associated proteins. The purification strategy provides a means of purifying other GPI proteins, including those produced by protein engineering techniques. 相似文献
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478.
A crude glucosyltransferase (GTase) preparation was obtained from the culture supernatant of Streptococcus mutans strain MT703 (serotype e) by 50% ammonium sulphate precipitation. Antiserum specific against the GTase was prepared by immunizing rabbits intramuscularly with the GTase in Freund incomplete adjuvant, followed by GTase without adjuvant intravenously. Gamma globulin fractions of the antiserum and normal serum were partially purified by 1/3 saturated ammonium sulphate precipitation. The antibody strongly inhibited the GTase activity (greater than 90%) of type c, e and f S. mutans, whereas the GTase of type a, d and g was not affected by the antibody. The GTase from type b S. mutans was slightly inhibited. The adherence of viable cells of type c, e, and f S. mutans to a glass surface due to synthesis of glucan by the cell-associated GTase was also significantly inhibited by the antibody to the enzyme. These results suggest that type c, e, and f and types a, d, and g S. mutans can be separated into two major groups in terms of the immunological relationship of GTase. 相似文献
479.
Mass vaccination campaigns against viral diseases, both human and animal, depend on the availability of cheap viral antigens. The eukaryote Dictyostelium discoideum has simple growth requirements and rapid growth rates and forms stable cell lines. These features, together with the possibility of secreting recombinant (glyco) proteins into a defined buffer, make the D. discoideum expression system an attractive option for producing economical recombinant subunit vaccines. 相似文献