光钳操纵生物活体的动态监测技术的研究

采用摄像、录像和视屏监控系统及显色偏振装置与光钳系统耦合,从空间分辨、色分辨和时间分辨多方面改善系统品质,实现了光钳捕获与操纵生物活体的动态监测、实时记录、资料保存和屏幕再现的功能,并能测量光钳操纵细胞的位移量和由此计算操纵速度,提高了光钳的自我调整和光钳操纵细胞的精细度。本研究为激光光钳技术在细胞工程等方面的应用研究提供了行之有效的技术手段。     

染色体辐射效应的微机检测 Ⅱ断片率 微核率与细胞畸变率间的相关性检测

本文继前文后,按照设计的线性回归程序在“IBM—PC/XT”微型计算机上,进一步检测了断片率、微核率与细胞畸变率之间的相关性,肯定了微核测定法,断片测定法可以替代染色体畸变分析法。     

Mutational analysis of the functional domains of yeast K1 killer toxin.

To determine the functional domains of K1 killer toxin, we analyzed the phenotypes of a set of mutations throughout regions encoding the alpha- and beta-toxin subunits that allow secretion of mutant toxins. A range of techniques have been used to examine the ability of mutant toxins to bind to beta-glucan cell wall receptor and to form lethal ion channels. Our results indicate that both the alpha and beta subunits are involved in beta-glucan receptor binding. Defects in ion channel formation and toxin immunity are confined to the hydrophobic alpha subunit of the toxin.     

A monoclonal antibody that inhibits opioid binding to rat brain membranes

To understand the structure-function relationship and to probe the molecular characteristics of the purified opioid receptor, monoclonal antibodies (mab) were raised against a purified opioid receptor protein. After intensive screening of almost 1500 hybridoma cell lines, only 7 clones were shown to have very high immunoreactivity against the purified receptor. Moreover, out of these 7 clones, only 2, 3B4F11 and 3A27G, were found to inhibit the ligand binding property of the mu-opioid receptor. The mab 3B4F11 was found to inhibit 3H-diprenorphine binding to the purified receptor in a dose dependent manner with a maximal inhibition of 100% achieved with 20 micrograms of the antibody. Likewise, Fab fragments prepared from the mabs 3B4F11 inhibited 3H-diprenorphine binding to P2 membranes in a dose-dependent manner. In addition, it was found that the binding of 3H-DAGO, 3H-DPDPE and 3H-EKC was inhibited with approximately equal potency, suggesting that the Fabs prepared from the mab 3B4F11 interact with all 3 receptor types.     

The interaction of quinone analogues with wild-type and ubiquinone-deficient yeast mitochondria

The interaction of the exogenous quinones, duroquinone (DQ) and the decyl analogue of ubiquinone (DB) with the mitochondrial respiratory chain was studied in both wild-type and a ubiquinone-deficient mutant of yeast. DQ can be reduced directly by NADH dehydrogenase, but cannot be reduced by succinate dehydrogenase in the absence of endogenous ubiquinone. The succinate-driven reduction of DQ can be stimulated by DB in a reaction inhibited 50% by antimycin and 70-80% by the combined use of antimycin and myxothiazol, suggesting that electron transfer occurs via the cytochrome b-c1 complex. Both DQ and DB can effectively mediate the reduction of cytochrome b by the primary dehydrogenases through center o, but their ability to mediate the reduction of cytochrome b through center i is negligible. Two reaction sites for ubiquinol seem to be present at center o: one is independent of endogenous Q6 with a high reaction rate and a high Km; the other is affected by endogenous Q6 and has a low reaction rate and a low Km. By contrast, only one ubiquinol reaction site was observed at center i, where DB appears to compete with endogenous Q6. DB can oxidize most of the pre-reduced cytochrome b, while DQ can oxidize only 50%. On the basis of these data, the possible binding patterns of DB on different Q-reaction sites and the requirement for ubiquinone in the continuous oxidation of DQH are discussed.     

梭曼等胆碱酯酶抑制剂对猫膈神经单纤维电活动的影响

在麻醉猫,经推动脉注入梭曼、VX,沙林及乙酰甲胆碱引起呼吸中枢严重抑制的剂量分别为0.5—1、3、15、2001μg/头;但在无麻醉、箭毒麻痹、人工呼吸并用药物保护循环的清醒猫,VX用量要增加十多倍,沙林用量增加2～8倍,棱曼用量不变。在严重抑制剂量的给药早期,梭曼使34.8％动物较早地出现膈神经单纤维放电加强,其每次吸气放电的冲动频率由20～30Hz增至50～80Hz,冲动个数由15～25个/每次放电增至40～60个/每次放电,兴奋持续短、迅速转入抑制且不易自动恢复;VX和乙酰甲胆碱使100％动物出现显著的放电加强,其冲动频率由20～30Hz增至70～130Hz、冲动个数由15～25个/每次放电增至60～80个/第次放电,兴奋持续时间较长、转入抑制慢但自动恢复较快;沙林使76.9％动物出现放电加强,其他表现类似VX。三种胆碱酯酶抑制剂和乙酰甲胆碱共使33/52根单纤维放电发生时相变化。结果表明:梭曼对呼吸中枢作用最强、沙林次之、VX最弱且更似乙酰甲胆碱。     

单面针的生物碱研究

自芸香科(Rutaceae)花椒属植物单面针(Zanthoxylum nitidum var. fastuosum How ex Huang)的根皮中分得五种已知生物碱:乙氧基白屈菜红碱(ethoxychelerythrine)(Ⅰ);氯化光花椒碱(nitidine chloride)(Ⅱ);去甲基白屈菜红碱(des-N-methychelerythrine)(Ⅲ);α—别隐品碱(α-allocryptopine)(Ⅳ);鹅掌揪宁(liriodenine)(Ⅴ).