鱼类染色体显带的研究 Ⅰ.鱼类染色体复制带显带的BrdU-Hoechst-Giemsa方法

本文报道显示鱼类染色体复制带的BrdU-Hoechst-Giemsa方法。采用含20％小牛血清的RPMI-1640培养液进行肾细胞培养,收获前按终浓度加入10μg/ml BrdU和2μg/ml放线菌素D,分别处理16—18小时和1.5—2小时。制片经Hoechst-33258染色,紫外灯照射,2×SSC温育和Gicmsa染色,获得了鲢鱼、鳙鱼和大鳍刺鳑鮍的染色体复制带图象,带纹清晰,结果较稳定。发现BrdU和放线菌素D有抑制鱼类染色体浓缩的作用。     

辽宁海城小孤山遗址发掘简报

从小孤山晚更新世洞穴遗址出土了38种哺乳动物化石、上万件石制品以及一批制作精美的骨角制品和装饰品。石器工业在技术与类型上和华北旧石器关系密切。大致相同的骨针和穿孔兽牙于三十年代曾在周口店山顶洞遗址发现过,但是与欧洲马格德林鱼叉相似的角制鱼叉在中国旧石器文化中是头一次发现。     

Invertase immobilization via its carbohydrate moiety

After periodate oxidation of its glycosidic component, invertase was covalently bound onto three types of modified solid supports: glycidyl methacrylate, styrene-divinylbenzene copolymers, and bead cellulose. Direct reaction of the invertase aldehyde groups that were formed with amino groups of the support and use of the modified Ugi reaction have been employed as immobilization procedures. Apart from binding methods, the important effects of the buffer, support, conditions of periodate oxidation, and the length of the spacer on the activity of the enzyme conjugate have been investigated. Superior conjugate activity was obtained, via modified Ugi reaction, by the immobilization of a suitably oxidized invertase to a styrene-divinylbenzene copolymer having free amino groups.     

利用米曲霉自身溶壁酶制备原生质体的研究

真菌原生质体融合作为生物工程的一种新技术,日益受到了人们广泛的重视,而制备原生质体则是原生质体融合的前提。各种真菌细胞壁的结构与化学组成不尽相同,因此制备不同种真菌的原生质体所要求的溶壁酶也有差异。曲霉制备原生质体一般可采用蜗牛酶,但米曲霉     

乙肝病毒前核区基因的功能

<正>乙型肝炎病毒(HBV)有一个表面抗原(sAg)蛋白包埋的脂外壳,壳内有核心颗粒,颗粒由病毒DNA,核心抗原(cAg)及DNA聚合酶和共价连接DNA5'端的蛋白组成。用二巯基乙醇和加热法,或用中等强度的蛋白酶降解法处理外壳,可使cAg转化为与之密切相关的e抗原(eAg)。一般认为,血清eAg是cAg的另一种形式,或是其衍生物。乙肝病毒急性感染期的肝细胞内出现高水平的sAg和cAg,但eAg水平低。此     

稻苞虫羽角姬小蜂生物学特性初步观察

<正> 稻苞虫羽角姬小蜂Dimmockia parnarae(Chu et Liao)常常从稻苞虫蛹中育出,在我县的寄生率一般为3—12％。1980年至1981年,作者对该蜂的生物学特性进行了观察,现将结果整理如下: 一、寄主 据资料记载,稻苞虫羽角姬小蜂既是初寄生蜂,又具有重寄生性。1981年作者从田间采集稻苞虫幼虫于室内饲养,获得稻苞虫蛹,银颜     

海城小孤山的骨制品和装饰品

小孤山的骨制品包括鱼叉、标枪头和骨针,它们在工艺上与欧洲旧石器时代晚期、尤其是马格德林文化的制品十分相似。小孤山的骨针和山顶洞的骨针相似,但工艺水平稍高。小孤山的装饰品包括穿孔牙齿和蚌壳,它们与山顶洞的同类制品基本一致,但穿孔技术稍高。小孤山含上述制品的堆积物的时代为晚更新世,年代测定的初步结果为距今40,000—20,000年左右。     

Effect of metabolic inhibitors and temperature on uptake and translocation of ca and k by intact bean plants

The dependence of Ca uptake and translocation by intact roots of Phaseolus vulgaris on concurrent root metabolism was investigated using ⁴⁵Ca-labeled Hoagland solutions at one-half and one-twentieth strength (2.5 and 0.25 mM Ca²⁺). Adsorbed and absorbed ⁴⁵Ca fractions in the roots were distinguished on the basis of the time course of exchange with the outer solution. Uptake of ⁴²K, of which the characteristics are better known, was measured for comparison. The absorbed ⁴⁵Ca fraction showed a markedly nonlinear increase with time in contrast to the near linear increase in ⁴²K. Exposure of roots to cyanide, arsenate, 2,4-dinitrophenol, or low temperatures caused only slight reductions in ⁴⁵Ca absorption by roots, but significant reductions of ⁴²K. In all treatments involving inhibitors and low temperatures, the translocation to shoots of both ⁴⁵Ca and ⁴²K was strongly inhibited. The conclusion that much of the absorbed ⁴⁵Ca fraction in the root tissue is taken up by processes which are not rate-limited by metabolism is discussed.