一种模拟高原低氧复合冷冻的简易动物实验舱

以氮稀释法使舱内氧含量维持实验模拟高度,以普通冰箱制冷系统维持舱内恒温,以多功能低温浴槽作为致冻装置。该舱可于２０ｍｉｎ内升至模拟６０００ｍ高度,每次可供１６只大鼠作高原冻伤实验。实验期间高度恒定于６０００±２００ｍ,舱温２１±１℃。相对湿度５５％±１５％,冷冻液－２５．０±０．５℃。该舱结构简单、使用方便,可在实验室中模拟高原条件进行冷冻实验研究。由于不使用人体减压舱,不仅避免了减压缺氧对实验人员的不利影响,也减少了实验消耗。     

巴氏碳球C_(60)对体外培养HeLa细胞的光敏杀伤效应

采用MTT比色分析法,观察了不同C_(60)浓度和不同光照强度下C_(60)对体外培养的HeLa细胞的光敏杀伤效应。结果表明,C_(60)在30μg/ml,光强4000Lux的条件下即可杀伤大部分细胞。受伤细胞圆缩、脱壁,里面颗粒增多,失去表面微绒毛状结构。当光强增大时,细胞表面甚至出现破损。     

利用固定化酵母细胞转化反式肉桂酸生产L—苯丙氨酸

研究了深红酵母（Ｒｈｏｄｏｔｏｒｕｌａｒｕｂｒａ）的培养基成分,培养固定化及转化条件,实验表明最佳基成分（％）葡萄糖０．５,胰蛋白胨０．５,酵母膏０．５,磷酸二氢钾０．０５,Ｌ－Ｐｈｅ０．０５,ｐＨ７．０,３０℃２０Ｌ发酵罐中培养１５～１７ｈ,最佳固定化条件为：用２．５％卡拉胶包埋１８％的湿菌体,最佳转化条件为：１．０％反式肉桂酸,４ｍｏｌ／Ｌ铵离子,ｐＨ０．５,３０℃,用卡拉胶固定化深红酵母（Ｒ     

Antitumor agents-CLXXV. Anti-tubulin action of (+)-thiocolchicine prepared by partial synthesis

(+)-Thiocolchicine (2b) was prepared from (±)-colchicine (1) in a five-step reaction sequence that included chromatographic separation of appropriate camphanylated diastereomers. Acid hydrolysis of the (+)-diastereomer, followed by acetylation, yielded the desired product 2b. (+)-Thiocolchicine has 15-fold lower inhibitory activity against tubulin polymerization than (−)-thiocolchicine, and is 29-fold less potent for inhibiting growth of human Burkitt lymphoma cells. The enantiomer 2a, prepared from the (−)-camphanylated diastereomer, had potent activity in all assays comparable to that of (−)-thiocolchicine prepared by other methods. These results support the hypothesis that the proper configuration of colchicine-related compounds is an important requirement for their anti-tubulin action.     

Sequence variation and genetic diversity in the giant panda

About 336–444 bp mitochondrial D-loop region and tRNA gene were sequenced for 40 individuals of the giant panda which were collected from Mabian, Meigu, Yuexi, Baoxing, Pingwu, Qingchuan, Nanping and Baishuijiang, respectively. 9 haplotypes were found in 21 founders. The results showed that the giant panda has low genetic variations, and that there is no notable genetic isolation among geographical populations. The ancestor of the living giant panda population perhaps appeared in the late Pleistocene, and unfortunately, might have suffered bottleneck attacks. Afterwards, its genetic diversity seemed to recover to some extent. Project supported by the “8.5” Key Project of Chinese Academy of Sciences, the Chairman Foundation of Chinese Academy of Sciences, K. C. Wang Education Foundation, the Applied Basic Research Foundation of Yunnan, the National Natural Science Foundation of China, the Special Foundation for Returned Chinese Scientists, and Zoological Society of San Diego.     

球形红杆菌积累聚β-羟基链烷酸(PHA)的研究

通过对球形红杆菌(Rhodobacter sphaeroides)生长和积累聚卢-羟基链烷酸(PHA)条件的研究,确定采用两段培养法提高PHA的产量。第一阶段提供适合菌体生长的条件:以葡萄糖作碳源,尿素为氮源,光照微好氧培养。第二阶段则提供使菌体积累PHA的条件:补加乙酸钠厌氧光照培养。经两段培养后菌体PHA含量可占细胞干重的45％,PHA产量每升发酵液可达1.7g。     

安徽南陵下三叠统青龙组鲎类足迹化石的发现

这是在我国首次发现的鲎类足迹化石,标本采自安徽南陵下三叠统青龙组薄层灰岩。除对它们的形态特征加以描述、分析和比较外,还就其形成环境及保存特点作了初步的探讨。     

昆虫卵黄发生研究进展

昆虫卵黄发生研究进展李乾君,龚和,管致和（中国科学院动物研究所北京１０００８０）（北京农业大学植保系北京１０００９４）昆虫卵的成熟一般分为三个时期－－卵黄发生前期（Ｐｒｅｖｉｔｅｌｌｏｇｅｎｉｃｓｔａｇｅ）、卵黄发生期（ｖｉｔｅｌｌｏｇｅｎｉｃｓｔａ...     

不同光学异构体组成的氯氰菊酯对敏感及抗性家蝇的神经电生理学研究

采用敏感家蝇(Musca domestica vicina L.)及由5种不同光学异构体组成的氯氰菊酯选育的抗性家蝇中胸足离体标本,观测五种药剂对足感觉神经纤维冲动发放的影响。各种异构体组成的氯氰菊酯均可引起感觉神经纤维发放的增加,然后逐渐降低,直至完全阻断。以阻断时间和加药剂量为参数,求出神经敏感度。结果表明：五种药剂作用于敏感家蝇的神经敏感度与室内生物测定的LD₅₀值(μg/头)无相关性,而与供试药剂中反α体与顺α体的比例有关,反α体所占比例越多的药物,神经敏感度越高。抗性家蝇的神经敏感度与敏感 家蝇相比大幅度下降,可以认为神经敏感度降低是家蝇对氯氰菊酯产生抗性的主要机制。抗性家蝇中,氯氰菊酯品系(RC₁)的抗生水平最高,但它的神经敏感度较其它抗性品系也高,由此推测,RC₁,的抗性机制与其它晶系有所不同。     

高必需氨基酸转基因马铃薯的研究

８０年代以来,马铃薯遗传转化系统日趋成熟,转基因工程植株已被广泛应用于基础科学研究［１］。作为食物蛋白和能量主要来源的马铃薯,提高其蛋白质含量及质量的遗传工程研究正受到人们的普遍关注［２］。Ｙａｎｇ等［２］将旨在改善氨基酸平衡的ＣＡＴ－ＨＥＡＡＥ（氯酶素乙酰转移酶－高含量人体必需氨基酸）融合基因导入马铃薯,获得了Ｓｏｕｔｈｅｒｎｂｌｏｔ、Ｎｏｒｔｈｅｒｎｂｌｏｔ、Ｗｅｓｔｅｒｎｂｌｏｔ的证据,但尚缺少氨基酸分析的资料。玉米醇溶蛋白（ｚｅｉｎ）［３］是一个富含甲硫氨酸的贮存蛋白,它和人工合成的ＨＥ…