喹诺酮类药物抗乙型肝炎病毒体外实验研究

本文以２．２．１５细胞株为模型,以ＨＢｓＡｇ、ＨＢｅＡｇ、ＨＢＶＤＮＡ、细胞存活率为观察指标,综合评价了喹诺酮类药物吡哌酸（ＰｉｐｅｍｉｄｉｃＡｃｉｄ）、氟哌酸（Ｎｏｒｆｌｏｘａｃｉｎ）、环丙氟哌酸（Ｃｉｐｒｏｆｌｏｓｘａｃｉｎ）、氟嗪酸（Ｏｆｌｏｘａｃｉｎ）体外抗ＨＢＶ效果。结果表明：吡哌酸、氟哌酸、环丙氟哌酸、氟嗪酸对ＨＢｓＡｇ、ＨＢｅＡｇ５０％抑制浓度（ＩＤ＿（５０））分别为１１μｇ／ｍｌ、６４μｇ／ｍｌ、９３μｇ／ｍｌ、１０５μｇ／ｍｌ和１９９μｇ／ｍｌ、１１１μｇ／ｍｌ、２４μｇ／ｍｌ、２１７μｇ／ｍｌ,细胞存活率为５０％时的药物浓度（ＣＤ＿（５０））分别为２１９μｇ／ｍｌ、９０μｇ／ｍｌ、１８１μｇ／ｍｌ、１６９μｇ／ｍｌ,在所选定的用药浓度范围内不同程度抑制培养上清液及细胞内ＨＢＶＤＮＡ及其复制中间体的产生。尤其对超螺旋结构ＤＮＡ（ｓｃＤＮＡ）有不完全抑制作用。     

恩拉霉素抗乙型肝炎病毒的体外实验研究

以ＨｅｐＧ２．２．２．１５细胞株为模型,以其分泌的ＨＢｓＡｇ、ＨＢｅＡｇ、ＨＢＶＤＮＡ及细胞存活率为观察指标,综合评价天然多肽类抗生素恩拉霉素体外抗ＨＢＶ效果。结果表明恩拉霉素对ＨＢｓＡｇ和ＨＢｅＡｇ的５０％抑制浓度ＩＣ５０分别为２７μｇ／ｍＬ和３４μｇ／ｍＬ,治疗指数（ＴＩ）分别为５．９和４．６。Ｓｏｕｔｈｅｒｎ结果显示,５０μｇ／ｍＬ恩拉霉素对细胞内游离ＨＢＶＤＮＡ抑制率为５６．８％。     

脱落酸对黄连体细胞胚胎发育的影响

用ＨＰＬＣ法测得黄连体细胞胚的内源ＡＢＡ含量,在胚性细胞团、球形胚、鱼雷形胚和子叶胚中分别为０．４５２、０．４６１、０．８３１和２．５０μｇ／ｇ ｆｒ．ｗｔ。培养基中加入４μｍｏｌ／Ｌ ＡＢ时,可最大幅度地提高正常子叶胚的和次生胚的产量,环己亚胺对体细胞胚（子叶胚）蛋白质合成的抑制率在含ＡＢＡ的培养基上显著高于不含ＡＢＡ的培养。由此推测,ＡＢＡ调节黄连体细胞胚发育的方式之一是诱导蛋白质合成。     

乙型肝炎血源疫苗皮内接种4年效果观察

为了解乙型肝炎血源疫苗皮内接种的持久效果,选ＨＢｓＡｇ、抗－ＨＢｓ和抗－ＨＢｃ均（－）的９～１１岁儿童１０３名,随机分成４组,分别皮内接种１μｇ×４和３μｇ×４（均按０,１,２,５月程序）和肌肉接种１０μｇ×３和３０μｇ×３（各按０,１,２月程序）。首针后４８月时,１μｇ、３μｇ、１０μｇ和３０μｇ组抗－ＨＢｓ≥１０ｍＩＵ／ｍＩ者各为６９．２％,８０．０％、９２．３％和８１．８％;ＧＭＴ则为１４．５,７９．０,４４．８和７０．９ｍＩＵ／ｍｌ,３μｇ×４皮内免疫的近期和远期效果与肌肉组３０μｇ×３相似,宜于某些人群采用     

脂多糖结合蛋白的结构和功能

脂多糖（ＬＰＳ）结合蛋白（ＬＢＰ）是存在于下沉人和动物血清中的种糖蛋白,人血清中ＬＢＰ的正常浓度为５～１０μｇ／ｍｌ,急性反应期可升高到２００μｇ／ｍｌ,ＬＰＢ与ＬＰＳ中的类脂Ａ具有高度亲和性,可作为ＬＰＳ载体蛋白,催化ＬＰＳ与ＣＤ１４结合,刺激单核细胞、内皮细胞等,促进Ｔ痰性介绍的释放;ＬＢＰ还可作为调理素,促进单核细胞等吞噬调理后的ＬＰＳ和甘兰阴性细菌,故ＬＢＰ可以调节ＬＰＳ所致的炎症反应。Ｂ     

灵芝多糖对人脐血LAK细胞活性的影响

本文研究了灵芝多糖（ＧＬＰ）对人脐血ＬＡＫ（ＣＢ—ＬＡＫ）细胞活性的影响,结果发现,单独ＧＬＰ能刺激人脐血单个核细胞（ＣＢＭＣ）增殖,但不能诱导ＬＡＫ活性,当与５０ｕ／ｍｌｒＩＬ—２伍用时,可增殖ＣＢ—ＬＡＫ细胞诱导活性,不同剂量ＧＬＰ（０．５—１００μｇ／ｍｌ）影响作用不同,以１０μｇ／ｍｌ浓度最好．在不同浓度ｒＩＬ—２（１０—１００ｕ／ｍｌ）诱导ＣＢ—ＬＡＫ细胞过程中加入ＧＬＰ（１０μｇ／ｍｌ）,可明显提高细胞增殖能力,减少ｒＩＬ—２用量。ＧＬＰ亦能促进效应阶段ＣＢ—ＬＡＫ细胞对Ｒａｊｉ肿瘤靶细胞的杀伤作用（Ｐ＜０．００１）。由此看出,ＧＬＰ具有增强ＣＢ—ＬＡＫ细胞活性的作用,是一很好的生物反应调节剂（ＢＲＭ）,有必要进行深入的研究。     

食物中牛磺酸含量

本研究测定了食品包括水果、蔬菜、种子、坚果、谷类、肉类、海产品和奶制品的牛磺酸含量。发现蚶和章鱼的牛磺酸;含量最高（４１．４μｍｏｌ／ｇ和３１．２μｍｏｌ／ｇ）,其次是小虾和鱼类（１２．４μｍｏｌ／ｇ和９．１μｍｏｌ／ｇ）。牛肉、猪肉和羊肉含有的牛磺酸范围为３．５～４．０μｍｏｌ／ｇ,鸡腿中的牛磺酸含量为６．６μｍｏｌ／ｇ,鸡胸肉为１．４μｍｏｌ／ｇ。鸡蛋（蛋黄和蛋白）、奶酪产品或蜂蜜中未发现含有牛磺酸。水果和蔬菜未检出牛磺酸。种子和谷类的检出结果为：稻米、玉米、麦片、裸麦、小麦、大麦、芝麻、咖啡豆、巧克力豆不含牛磺酸,南瓜子含１３．５ｎｍｏｌ／ｇ,黑豆含９．２ｎｍｏｌ／ｇ,蚕豆含１２．９ｎｍｏｌ／ｇ,嫩豌豆含１８．７ｎｍｏｌ／ｇ,花生未检出牛磺酸。胡桃、杏仁、如树坚果、榛子和松子中牛磺酸的含量范围为１５～４６ｎｍｏｌ／ｇ,阿月浑子含很少量的牛磺酸（４．９ｎｍｏｌ／ｇ）。所有分析是以不经烹调的样品完成的。这些结果的重要性可以认为是人体和动物牛磺酸缺乏有害结果的依据。     

微丝在卵子极性产生,分裂沟形成和极体排放中的作用

小鼠生发泡期卵母细胞在１μｇ／ｍｌ细胞松弛素Ｂ中培养，部分微丝解聚，卵母细胞不能产生极性而在细胞中部形成分裂沟（假分裂）；极泡期卵在１μｇ／ｍｌ ＣＢ 中，分裂沟继续收缩，排和放第一极体，假分裂的分裂沟和极区分裂沟形成均与分裂器中体位置相关，部分微丝解聚并不影响假分裂和第一极体的排放，全部微丝解释（１０μｇ／ｍｌ ＣＢ）将中断假分裂和胞质分裂，分裂沟消失，卵恢复球形，由此可见，成熟过程中卵母细胞极     

黄花蒿培养细胞中青蒿素合成代谢的体外调节

黄花蒿培养细胞通过两步培养积累青蒿素．第１步在含有０．２～０．４ｍｇ／Ｌ６－苄基氨基嘌呤（６－ＢＡ）和３～４ｍｇ／Ｌ吲哚乙酸（ＩＡＡ）的Ｎ６培养基中进行细胞的增殖培养,第２步将培养好的细胞转入含０．２～０．４ｍｇ／Ｌ６－ＢＡ和０．２～０．４ｍｇ／ＬＩＡＡ的改良Ｎ６培养基中进行青蒿素的合成．青蒿素的合成量为１９０μｇ／ｇ干细胞左右．当在第２步培养中加入青蒿素合成前体青蒿酸,青蒿素合成量比仅靠激素诱导提高了３倍多．青蒿素的合成途径是植物固醇合成途径的分支途径,当在青蒿素合成过程即第２步培养中加入固醇生物合成抑制剂双氯苯咪唑和氯化氯胆碱处理,可使代谢向合成青蒿素的方向移动,青蒿素合成量明显提高．经２００ｍｇ／Ｌ氯化氯胆碱处理２ｄ,黄花蒿细胞合成青蒿素量为３７２μｇ／ｇ干细胞;经２０ｍｇ／Ｌ双氯苯咪唑处理４ｄ,黄花蒿细胞合成青蒿素量为１５４０μｇ／ｇ干细胞,比靠激素诱导提高了８倍多,与诱导脱分化细胞的黄花蒿叶中所含的青蒿素（３０００μｇ／ｇ干细胞）处于同一个数量级．以上结果表明：在通过植物激素调节可以合成青蒿素的黄花蒿培养细胞中,缺乏青蒿素合成前体是青蒿素合成量低的重要原因．因此,在青蒿素合成的过程中通过体外调节,     

新鲜蜂王浆和6-BA对水稻种子萌发和离体白菜叶片叶绿素含量的影响

经用１０－３ｇ／Ｌ、１０－２ｇ／Ｌ、１０－１ｇ／Ｌ６ＢＡ和１０－２,１０－１、１ｇ／Ｌ新鲜蜂王浆处理水稻种子和离体白菜叶片后,水稻种子发芽率均高于对照值,其中１０－２ｇ／Ｌ的６ＢＡ和１ｇ／Ｌ的蜂王浆效果最佳。而离体白菜叶片叶绿素含量也比对照高,其中１０－３ｇ／Ｌ的６ＢＡ和１ｇ／Ｌ的蜂王浆效果最佳。１０－２ｇ／Ｌ的６ＢＡ和１０－２ｇ／Ｌ的蜂王浆混合处理白菜叶片,其效果要比单独用６ＢＡ和蜂王浆处理好。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

Synthesis of hapten and conjugates of coumestrol and development of immunoassay

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Effect of soil salinity and water stresses on growth and content of nitrogen,chloride and phosphate of wheat and triticale

Summary Three wheats and one triticale were grown, up to flowering stage, in pots on calcareous soil adjusted to a range of salinities (S₁=3.5, S₂=6, S₃=8.5, and S₄=11 mmhos/cm, 20°C, soilpaste extract) by adding solution consisting of 3∶2∶1 of Na-, Ca- and Mg chlorides in chemical equivalent amounts. Moisture in the pots was kept at 100% (W₁), 40% (W₂) and 20% (W₃) of the available water. The vegetative growth, nitrogen and phosphate were affected by S and W treatments, chloride was affected only by S. The interaction S×W affected only dry weight. Varietal effect was observed between wheat as a group and triticale. Multiple quadratic regression equations of these properties on salinity and water revealed that the higher the available water the wider the range of tolerable salinity. Triticale was relatively more tolerant to water stress. Salinity increases Cl and decreases N, whereas water stress enhances N accumulation to a certain extent. However, in triticale at S₃ and S₄ the effect of water stress on N was overshadowed by the excessive salinity. This did not occur for the wheat (Florence). P trends were described. R² for P was low (0.7435–0.3603) which made interpretations rather difficult.     

放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响

研究放牧对草地植物生理活动的影响,对于揭示草地放牧演替的生理机制有重要意义.大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段.放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势.牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关.放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关.