应用RAPD技术对大熊猫分类地位的探讨

采用ＰＣＲ和Ｓｏｕｔｈｅｒｎ杂交等方法对大熊猫与小熊猫、马来熊、浣熊等共有的一条１．３ｋｂ的ＲＡＰＤ产物片段进行了初步分析。研究结果显示,来自于大熊猫的此共有片段可能为一重复序列,并且其内部含有多个随机引物ＡＢ１－０８的结合位点。以此来自于大熊猫的１．３ｋｂ片段为探针进行杂交,发现马来熊ＲＡＰＤ产物中的对应片段显示了很高的同源性,而小熊猫和浣熊ＲＡＰＤ产物则无相应的杂交带。这暗示,从分类地位上来看,大熊猫与熊科马来熊的亲缘关系应更近于与小熊猫和浣熊的亲缘关系,应与马来熊一样划分为熊科。本研究为大熊猫分类地位的确定提供了又一分子生物学证据     

四川自贡大山铺成渝龟科—新属

描述了产自四川自贡大山铺恐龙化石坑中的三件龟甲标本,命名为一新属新种—周氏四川龟（Sichuanchelyschowigen．etsp．nov．）。该属以椎盾极横宽,中部缘盾极狭长为主要特征,它代表了成渝龟科中一类较特别的类型。     

人Ⅳ型胶原的提纯及其抗血清制备

采用胃蛋白酶限制性消化,NaCl分级盐析,还原和烷基化反应,纤维素离子交换层析从人胎盘组织分离纯化Ⅳ型胶原.经SDS-PAGE电泳鉴定符合Ⅳ型胶原α肽链电泳带.用纯化的Ⅳ型胶原免疫兔制备出高效价的特异抗血清.     

琼脂糖电内渗对电泳的影响

用电内渗不同(0、0.03、0.08、0.20mr)的琼脂糖制成凝胶或电极缓冲液凝胶条,观察对电泳行为的影响.结果表明等电聚焦电泳必须使用无电内渗琼脂糖.不同电内渗的琼脂糖制成的电极缓冲液凝胶条对SDS电泳无显著影响,但对常规聚丙烯酰胺凝胶电泳有不同程度的影响,电内渗越高,越不利于电泳的进行.     

Non-crystallographic symmetry of crystal of neutral phospholipase A2 from Agkistrodon halys Pallas

Agkistrodotoxin, a neutral phospholipase A₂ with high presynaptic neurotoxicity from the venom of Agkistrodon halys Pallas, has been crystallized by hanging drop vapor diffusion method. The crystal belongs to P2₁ space group with the cell dimensions a = 10.836 nm, b=8.486nm, c = 7.082nm, β=109.87$ showing C2 pseu-do-symmetry. Diffraction data to 0. 26 nm resolution have been collected on a Siemens X-200B area detector. C2 pseu-do-symmetry suggests that there exists a non-crystallographic two-fold axis parallel to crystallographic b axis. Self-rotation function calculation with different integrated radius and resolution ranges using the program POLARRFN yields four stable high peaks corresponding to three more non-crystallographic two-fold axis and one special non-crystal-lographic symmetry. The molecules in the asymmetric unit are suggested to be arranged in a manner of "dimer of dimers" by inference.     

赤霉素与脱落酸对番茄种子萌发中细胞周期的调控

利用细胞流检仪检测番茄（Ｌｙｃｏｐｅｒｓｉｃｏｎ ｅｓｃｕｌｅｎｔｕｍ Ｍｉｌｌ．） ＧＡ－缺陷型、ＡＢＡ－缺陷型和相应的正常品种（野生型）成熟种子胚根尖细胞倍性水平时发现：ＧＡ－缺陷型和野生型种子绝大多数细胞ＤＮＡ 水平为２Ｃ,而ＡＢＡ－缺陷型种子则含有较多的４Ｃ细胞。在标准发芽条件下,ＡＢＡ－缺陷型和野生型种子浸种１ ｄ 后胚根尖细胞ＤＮＡ 开始复制,随后胚根突破种皮而发芽。然而ＧＡ－缺陷型种子除非加入外源ＧＡ,否则既不发生细胞ＤＮＡ 复制,也不发芽。这说明内源ＧＡ 是启动番茄种子胚根尖细胞ＤＮＡ 复制的关键因素,同时也说明番茄根尖细胞ＤＮＡ 复制是种子发芽的必要条件。实验证明：ＡＢＡ 不抑制细胞ＤＮＡ 合成,但阻止Ｇ２ 细胞进入到Ｍ 期。外源ＡＢＡ处理野生型种子与渗控处理结果相似,可以大幅度提高胚根尖４Ｃ／２Ｃ细胞的比例,但抑制种子的最终发芽     

编码天麻抗真菌蛋白cDNA的分子克隆

用重组ＤＮＡ 技术研究了编码天麻抗真菌蛋白（ＧＡＦＰ）的基因,从天麻（Ｇａｓｔｒｏｄｉａ ｅｌａｔａＢｌ．）块茎中提取Ｐｏｌｙ（Ａ） ｍ ＲＮＡ 后合成ｃＤＮＡ,构建成表达型ｃＤＮＡ 文库,用纯化的蛋白质探针通过免疫筛选找出对应的ｃＤＮＡ 克隆。在进一步证明所选用的ｃＤＮＡ 克隆含有重组的λ－ｐｈａｇｅ ＤＮＡ 后,提取和纯化含有插入片段重组子的ＤＮＡ,用Ｅｃｏ ＲＩ酶切分析可见插入片段。已分离出编码天麻抗真菌蛋白的基因     

番茄种子发芽及渗控处理过程中的水分关系

干燥番茄（Ｌｙｃｏｐｅｒｓｉｃｏｎ ｅｓｃｕｌｅｎｔｕｍ Ｍｉｌｌ． ｃｖ． Ｍｏｎｅｙｍ ａｋｅｒ）种子浸种吸水有明显的３ 个阶段,尽管种子不同部分吸水的速度不一样,但整粒种子需１０～１２ ｈ 才能基本完成第一阶段的吸水。胚乳对种胚伸长和生长的机械压力明显阻碍种胚的吸水,即使在第二阶段整个种子水势与浸种溶液基本达到水分平衡时,种胚的水势仍然低于整个种子水势０．６～０．９ ＭＰａ。发芽过程中ＧＡ 和ＡＢＡ不直接影响番茄种子吸水。番茄种胚水势与含水量的关系呈幂指数的正相关。无论在浸种还是渗控处理过程中,番茄种胚压力势的总变化趋势是下降的     

大鼠中脑腹侧被盖区在睡眠－觉醒调节中的作用

本实验在３１只清醒自由行动的雄性ＳＤ大鼠进行。结果如下：（１）双侧中脑腹侧被盖区（ＶＴＡ）微量注射３．３ｎｍｏｌ溴隐亭后第２—３ｈ觉醒时间显著增加（Ｐ＜０．０１）;６．６ｎｍｏｌ溴隐亭有类似效果;０．６６和１．３３ｎｍｏｌ溴隐亭无明显作用。（２）同样方法ＶＴＡ微量注射２ｎｍｏｌ和４ｎｍｏｌＳＣＨ２３３９０后第２—３ｈ觉醒时间明显减少（分别为Ｐ＜０．０１和Ｐ＜０．０５）,但注射３．４ｎｍｏｌ舒必利则无效。（３）红藻氨酸（０．３μｇ）双侧ＶＴＡ注后一周,大鼠白天觉醒减少,夜间无明显变化。以上结果表明溴隐亭微量注射到ＶＴＡ可能通过Ｄ１受体使多巴胺神经元活动增加而产生致觉醒作用;另外ＶＴＡ中ＤＡ神经元对于维持日间的觉醒可能有紧张性作用。     

New taxol assay method using tubulin-assembly stimulation

Summary A novel taxol determination method which involves the tubulin-assembly stimulation is described. The tubulin-assembly was monitored by turbidity change at 350nm. In a limited range of taxol concentration (0 to 24 M), taxol stimulated tubulin-assembly linearly. And this linear relation was observed from 20min to 30min after the reaction started. Bioactive derivatives of taxol, such as cephalomanin and 7-epi-10-deacetyltaxol also stimulated the tubulin-assembly. However, baccatin III, which was known as less active taxol derivative did not stimulate tubulin assembly. This result showed that the stimulation of tubulin assembly has a relationship with the antimiotic activity. This assay method have several advantages. 1) Time required for the measurement is relatively short. 2) Multiple samples can be measured simultaneously. 3) It can remove interference of less active taxane compounds more selectively than immuno-assay. Consequently, this method can be used to determine taxol concentration in biological samples. Especially, this method can be used for large scale selection of cell line and primary screening of new antimiotic compounds.