Combinatorial and synergistic properties of CaMV 35S enhancer subdomains.

We have analyzed expression conferred by five subdomains of the cauliflower mosaic virus (CaMV) 35S enhancer in mature transgenic plants. Expression was detected from subdomains that gave no expression at earlier stages of development indicating developmental regulation of expression and confirming the modular organization of the enhancer. In several cases the expression patterns are highly restricted in cell type, providing useful markers for developmental studies. Comparison of expression patterns conferred by various combinations of 35S enhancer cis-elements suggests that synergistic interactions among cis-elements may play an important role in defining tissue-specific expression. This has implications for the nature of a cis-element combinatorial code that could define expression throughout development.     

Na~(+)、Ca~(2+)、Cu~(2+)和Zn~(2+)与HSA相互作用的~(23)(Na)-NMR研究

 本文应用~23Na-NMR波谱技术,研究了Na~(+)、Ca~(2+)、Cu~(2+)和Zn~(2+)与人体血清白蛋白(HSA)的相互作用。在实验基础上,通过引入两位快交换模型,拟合计算获得了Na~(+)与HSA相互作用的结合常数和处于结合状态Na~(+)的相关时间;实验表明Ca~(2+)能与Na~(+)竞争同HSA结合,拟合计算获得了两者与HSA相互作用结合常数的比值,棕榈酸钠能增强Ca~(2+)同Na~(+)竞争与HSA结合的能力;从实验上未能观察到Cu~(2+)、Zn~(2+)能同Na~(+)竞争与HSA相互作用的证据。     

冬虫夏草多糖的分子结构与免疫活性

 冬虫夏草多糖(在本文中名为CS-81002)是由冬虫夏草菌Cordyceps sinensis(Berk)Sacc在人工发酵条件下产生的胞外多糖。用凝胶过滤法测出CS-81002的分子量Mr=43kD。CS-81002的单糖组成为Man:Gal:Glc=10.3:3.6:1。甲基化分析和部份酸水解结果表明,CS-81002是多分支的杂多糖,由→6)-Manp-(1→形成主链,大约每10个主链Man残基中,有6个在C3位上被取代(即形成→3,6)-Manp-(1→分支),有4个在位C2上被取代(即形成→2,6-Manp-(1→分支),从而形成侧链。主链中还有少许未被取代的Man残基。侧链则由→3-)-Galf-(1→,→4)-Glcf-(1→,→4)-Manp-(1→和→2)-Manp-(1→组成。位于非还原末端的,则三种单糖残基都有。CS-81002在5mg/kg体重×12剂量条件下,对正常的昆明小鼠腹腔巨噬细胞吞噬功能有显著促进作用。在同样剂量条件下,对正常LACA小鼠脾脏溶血斑形成细胞(PFC)对绵羊红细胞的溶血作用无显著影响。不同程度的部份酸水解可使CS-81002的分子量下降,分支减少,并且对巨噬细胞吞噬功能的促进作用亦有下降趋势。在所得到的各个部份酸水解级分(分子量分别为41000,40000,32000,16000和12000)中,分子量为12000的级分对巨噬细胞吞噬功能无促进作用。     

人黑色素瘤细胞分泌的组织纤溶酶原激活剂(t-PA)的纯化

 本文报道了培养的人黑色素瘤细胞分泌的组织纤溶酶原激活剂(t-PA)的纯化方法。Bowes株人黑色素瘤细胞的分泌产物,经CM-Sephadex C--50层析,赖氨酸-Sepharose 4B,苯甲眯-sepharose 4B亲和层析后,即可得到纯化470倍的蛋白纯品。样品经聚丙烯酰胺凝胶电泳鉴定为均一单带,测得其分子量约为72kD。纯化的t-PA与尿激酶相比较,发现前者有更高亲和纤维蛋白的能力。     

紫竹梅雄蕊毛细胞发育过程中胞间连丝超微结构的变化

紫竹梅（Ｓｅｔｃｒｅａｓｅａ ｐｕｒｐｕｒｅａ）雄蕊毛细胞间的胞间连丝随着细胞的生长、发育、衰老而呈现动态变化的过程．花蕾和开放花的雄蕊毛细胞间的胞间连丝,具备胞间连丝的一般结构,直径约５０ ｎｍ ．衰老花雄蕊毛细胞间的胞间连丝拓宽,内部结构逐步降解、撤离,呈开放式通道,直径约１００ ｎｍ ． 在胞间连丝的动态开放过程中,细胞内的细胞器也发生相应变化． 对胞间连丝形成开放性通道及其机理进行了讨论     

从玉米胚中大量制备植物钙调素

从每公斤萌发２４ｈ的玉米胚丙酮粉中可提纯得６３ｍｇ的钙调素（ＣａＭ）,这是目前从每公斤植物材料中所提纯得ＣａＭ的最高记录。对其理化性质的研究表明,玉米胚ＣａＭ 有较高的生物学活性,能较好地激活磷酸二酯酶,其紫色吸收光谱,ＳＤＳ－ＰＡＧＥ电泳行为及氨基酸组成与其它的植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ的适宜材料。     

Evaluation of hydroxyl radical-scavenging property of garlic

While antibiotics are broadly used in dental and medical therapy, little attention has been directed towards the potential toxic side effects of antibiotics on tissue regeneration. Here we examined the effect of a quinolone antibiotic, pefloxacin (Rhone Poulenc) on rat parotid gland responses to chronic isoproterenol treatment. Groups of rats received injections of isoproterenol to induce glandular growth, saline (controls), pefloxacin, or isoproterenol and pefloxacin in combination. Parotid gland weight decreased significantly after pefloxacin treatment for 7 days as well as inhibiting glandular enlargement provoked by isoproterenol. The same trend was observed for the rates of DNA synthesis, with the incorporation of [³H]-thymidine in isoproterenol/pefloxacin-treated rats reduced to 49% of isoproterenol treatment alone levels. Saline-treated animals were 42% of the rate of [³H]-thymidine incorporation into DNA observed in isoproterenol treated rats. While isoproterenol treatment increased steady-state mRNA levels for fos, jun, myc, src, c-erbB-2, ras and topo II, inclusion of pefloxacin with the isoproterenol regimen blocked these increases. Pefloxacin treatment by itself did not alter proto-oncogene mRNA levels in the parotid gland. Glandular amylase activity was decreased in the pefloxacin treated group, while the combination of isoproterenol with pefloxacin did not decrease glandular amylase levels to the extent of that observed with -agonist treatment alone. In acute experiments, pefloxacin significantly decreased the volume of saliva secreted by the parotid gland. These results suggest that quinolone-based antibiotics disturb the secretory function of the parotid gland and can inhibit cell proliferation and regeneration. (Mol Cell Biochem 165: 55–63, 1996)     

部分酶解酵母高效电击转化研究

以酵母质粒YCp50为外源DNA,电击转化部分酶解酵母宿主菌AB1380,转化效率稳定在10~6转化子/μg质粒DNA左右,比不酶解酵母或酵母原生质球作受体的电击转化效率高一个数量级以上,也比PEG介导的酵母原生质球转化高3～5倍,而且适合于大片段DNA如水稻YAC分子的转化。达最佳转化时的有关技术参数为:新接菌种通气培养至细胞密度1×10~8～1.5×10~8个/ml;转化时细胞密度控制在1×10~9～1.5×10~9个/ml;每毫升酶解缓冲液加15u溶菌酶(lyticase),30℃下处理酵母5min进行部分酶解;电击时,电场设置在6.25kV/cm、电容25μF,电击后直接铺板。     

猪精子凝集素的纯化,性质及其作用

用胎球蛋白－Ｓｅｐｈａｒｏｓｅ亲和层析和凝胶过滤层析从精子和精浆中分离纯化了猪精子凝集素（简称ＢＳＬ）。ＢＳＬ的血凝活性只被若干糖蛋白和聚糖所抑制。ＢＳＬ的分子量为５６ｋｄ,由分子量分别为１３．６ｋｄ（β）和１６．０ｋｄ（α）的两个不同的亚基以α１β３所组成。ＢＳＬ为糖蛋白,含中性糖３．２％,不含唾液酸。用ＥＬＩＳＡ法测定猪精子中ＢＳＬ的含量及分布,表明７０％嵌入在精子膜中,２５％结合在精子表面,