三聚氰胺泌尿系统结石大鼠模型的研究

目的观察工业原料三聚氰胺连续给药诱发SD大鼠尿结石的成模情况。方法60日龄SPF级SD大鼠130只,雌雄各半,体质量（200＋24）g,随机分为给药5个组和空白对照组各20只,溶媒对照组10只。给药组分别给予三聚氰胺0．05、0．1、0．2、0．3、0．4g／（kg·d）连续灌胃;溶媒对照组灌胃10g／L甲基纤维素蒸馏水2mL／（只·d）,空白对照组灌胃无菌水2mL/（只·d）。采用体视显微镜观察大鼠肾脏、输尿管和膀胱形态改变,比较各组肾脏、膀胱的质量和脏器指数,观察大鼠CREA、BUN、UA、Ca、P、Mg含量变化。结果0．4g／kg组给药20d,0．2、0．4g／kg组给药30d,肌酐高于空白对照组;0．4g/kg组给药30d,尿素氮、尿酸高于空白对照组。给药20d各组血钙、磷、镁均偏低。给药30d,0．05、0．2、0．3、0．4g／kg组左肾质量比空白对照组增加。各组肾脏大小、颜色均与正常对照组比较接近,未见结石和明显黄色沉淀物,但有部份肾脏在皮、髓质交界处有点状或片状出血灶。输尿管未见结石。部分膀胱粘膜充血,部分雄性大鼠出现膀胱结石,其中给药20d各组雄性大鼠出现率为52％（13／25）,30d各组出现率为56％（14／25）,膀胱结石颜色多为淡黄色混合白色、白色。结论（0．05～0．4）g/kg三聚氰胺连续给药30d,对肾脏损害轻微,可诱发雄性大鼠产生膀胱结石。     

黔西北土法炼锌废弃地植被重建的限制因子

以土法炼锌废弃地的废渣、污染土壤和背景土壤为基质材料,分别种植黑麦草(Lolium perenne)和三叶草(Trifolium pretense),分析各种基质的基本化学特性、重金属(Pb、Zn、Cd)含量及其赋存形态、两种植物生长特性.结果表明,土法炼锌废渣上植被重建的主要限制因子包括高盐碱胁迫、有机质含量低、养分缺乏(TN、碱解N、TK).废渣重金属含量高,有效态含量低,对植物毒性小,但存在潜在危害性.污染土壤重金属含量低于废渣,但生物有效态重金属含量高.污染土壤植被重建的限制因子包括重金属毒性、P和K的有效性.废渣与污染土壤混合是土法炼锌废弃地基质改良的有效途径.     

Analysis of the Maize 19 kD Zein Gene Promoter Fragment Driving Seed specific Expression

A deletion works of a maize 19 kD zein gene promoter in the 5'end was performed and six promoter fragments of different length were obtained. A series of expression vectors was constructed and then transferred into tobacco ( Nicotiarta tabacum L. ) plants. GUS activity assays indicated that the expression of 488 bp promoter was tissue-specific, for which GUS was active only in transgenic tobacco seeds. The other four fragments containing 378 bp,302 bp,152 bp and 124 bp also have the activity of promoter. They could drive gus gene expressed not only in seeds but also in roots and petioles.     

顺德生态乐园之土壤及其合理利用建议

广东省顺德生态乐园内的土壤形成发育受气候、生物、地形地貌、母质母岩和人为干扰等５大因素的影响,其中人为活动是导致土层结构破坏和水土流失的主要原因。酸度高、肥力低、土质较好是园内土壤的一个共同特征。在各类土壤中,坡地赤红壤的面积最大,超过７０％,但坡项土层瘠薄。水稻土有较长耕作历史,并已形成了潜育层和潴育层,但土壤肥力并不高。泥炭土有较高的有机质含量,但土壤过酸,速效养分含量过低,难以直接利用。因此     

植物激素与谷类作物籽粒发育

介绍了细胞分裂素、赤霉素、生长素和脱落酸与谷类作物籽粒发育之间的关系。     

Synthesis of protoporphyrin IX induced by 5-aminolevulinic acid in yeast cells in the presence of 2,2;-dipyridyl

5-Aminolevulinic acid (ALA), a precursor of porphyrin synthesis, increased the production of various porphyrin compounds in Candida guilliermondii cells. Metalloporphyrins and protoporphyrin IX (PPIX) were predominantly accumulated, respectively, at ALA concentrations of 0.2-0.4 mM and at those higher than 1.5 mM. 2,2;-Dipyridyl which complexed with bivalent metals significantly increased the content of endogenous PPIX even at ALA concentrations lower than 0.5 mM. Under these conditions, the yeast sensitivity to photodynamic effect of visible light (400-600 nm) dramatically increased due to photosensitization by endogenous PPIX.