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41.
42.
Abidin Bin Hamid John E. Smith 《Journal of industrial microbiology & biotechnology》1987,2(3):137-141
Summary Phenobarbital stimulated aflatoxin biosynthesis byAspergillus flavus and this was paralleled by an increase in microsomal NADPH-cytochromeP-450 reductase and cytochromeP-450 activities. Aflatoxin biosynthesis was inhibited by SKF 525-A, metyrapone and cyanide, inhibitors of the cytochromeP-450 monooxygenase system, further suggesting that aflatoxin biosynthesis byA. flavus could be mediated by a cytochromeP-450 monooxygenase enzyme system. 相似文献
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Cd binding capacity and pulse polarography were used to study the inducibility of sulfhydryl groups in cultured Chinese hamster ovary cells (wild type and a Cd-resistant mutant) in response to dexamethasone (dex) and Zn. Evidence is presented that both the wild type and the mutant responded to dex and Zn treatment by induction of sulfhydryl groups. In wild type for Zn and dex as well as in the mutant for dex, this induction seems to be in the form of sulfhydryls attached to particulate or membrane fractions in the cells. For Zn in the Cd-resistant mutant the induction was in the form of metallothionein. 相似文献
45.
Ethionine, a hepatocarcinogen, was administered into rats 24 h before partial hepatectomy and immediately thereafter. Hepatic precursor ribosomal RNA (pre-rRNA) obtained 20 h after the operation of rats injected with ethionine and adenine resulted in methyl deficiency as judged by the incorporation of [3H]methyl group of S-adenosylmethionine into nuclear rRNA by partially purified rRNA methylase. The ethionine and adenine treatment causes methyl deficiency of nuclear rRNA at 2'-hydroxyribose sites of cytidine and uridine, but not at base sites. Although the ethionine and adenine treatment produced no significant change in total hepatic RNA synthesis in vivo assayed by the incorporation of labeled orotate, a one-third increase in nuclear rRNA synthesis as well as a one-third decrease in microsomal rRNA synthesis was found under the treatment. These results suggest that the undermethylation at 2'-hydroxyribose of pre-rRNA in liver nucleus, which is caused by ethionine and adenine administration into rats, causes an inhibition of the processing of nuclear pre-rRNA to cytoplasmic rRNA. 相似文献
46.
S.Y.K. Wen D. Hess J.W. Kauffman J.M. Collins L.J. Lis 《Chemistry and physics of lipids》1983,32(2):165-173
Raman spectroscopy and X-ray diffraction are used to study the effect of heat and Ca2+ on dimyristoylphosphatidylethanolamine dispersions. Unlike phosphatidylcholine dispersions, dimyristoylphosphatidylethanolamine bilayers (at pH 8) require heating above Tm in order for hydration to occur and apparently bind Ca2+ at very low levels. These results are related to models for membrane fusion. 相似文献
47.
Survival of Shigella in Sewage: II. Effect of Glycerol on Shigella flexneri and Shigella Bacteriophage1 下载免费PDF全文
Glycerol (30%) inhibited or delayed the adsorption of Shigella bacteriophage on its host organism, S. flexneri II; glycerol also inhibited or delayed the burst of phage, whether or not adsorption was carried out in the presence of glycerol. Studies of the mechanisms of these effects showed that viscosity and osmotic shock probably were not responsible for either phenomenon. The inhibition of adsorption, however, was proportional to the concentration of glycerol, and appeared to be a function of the hydroxyl groups on the glycerol molecule. The inhibition of burst seemed to be related to the osmotic pressure outside the bacterial cells. 相似文献
48.
云南10个民族红细胞酸性磷酸酶型分布调查 总被引:1,自引:0,他引:1
用淀粉凝胶电泳法对云南省汉族及9个少数民族的红细胞酸性磷酸酶(ACP_1)的表型分布进行了调查,检出A、BA和B3种表型,计算得云南汉、彝、白、傣、瑶、佤、哈尼、布朗、基诺和拉祜族ACP_1~A、ACP_1~B的基因频率依次为0.2067、0.7933;0.2406、0.7594;0.2341、0.7659;0.3750、0.6250;0.2300、0.7700;0.2727、0.7273;0.3594、0.6406;0.3036、0.6964;0.2381、0.76119和0.4474、0.5526。未发现ACP_1~C基因及其它稀有基因。研究表明,ACP_1表型的分布存在着一定的种族与民族差异。 相似文献
49.
用免疫荧光单克隆抗体对脊髓灰质炎病毒抗原表位的分析 总被引:1,自引:0,他引:1
用间接免疫荧光与中和试验筛选出来的抗脊髓灰质炎2型与3型不同毒株的12个单克隆抗体,其中3个仅有免疫荧光活性,9个具有中和与免疫荧光活性。用免疫荧光活性的单克隆抗体进行试验,发现它们在识别特异性抗原表位方面与中和性单克隆抗体相似,显示出株特异的、几个毒株共同特异的或型特异的抗原表位。根据表位分布关系及特征,可以用来鉴别型内毒株的特征、毒株的抗原分析、抗原变异的研究以及疫苗相关病例的鉴别。所得结果与中和性单克抗隆抗体及T1-寡核苷酸指纹图谱分析一致。而免疫荧光单克隆抗体识别抗原表位的活性范围比中和性单克隆抗体更广。另外还发现某些兼有荧光与中和两活性的同一个单克隆抗体,用不同方法(IF与NT)进行试验时,与相同毒株出现不同表位反应,这点是值得引起注意需待进一步证实的重要问题。 相似文献
50.
Frond senescence in Lemna gibba G3 was characterized, and itscontrol by light, ABA and kinetin investigated. The plant exhibitsa determinate growth pattern with a frond producing a set numberof daughter fronds before undergoing senescence and death regardlessof whether or not it flowers. When a frond was cut in half,the distal half (half frond) which lacks any meristem underwentrapid senescence as compared with intact fronds. In both intactand half fronds, the onset of senescence was accelerated byABA and retarded by kinetin. Continuous white light acceleratedsenescence in both intact and half fronds over the dark controls.Under different photoperiodic light regime, the pace of daughterfrond production is accelerated in proportion to the lengthof light period. In half fronds, however, very short photoperiodiclight treatments (e.g. 1L: 23D or 3L: 21D) rather delayed senescenceover the dark controls. Two separate light control systems operatingin opposite directions in Lemana senescence appear to exist.
1Present address: Department of Biology, Yonsei University,Seoul 120-749, Korea
2Present address: U.S. Department of Agriculture, Aero SpaceBuilding, Rm. 323, 901 D Street, S.W., Washington, D.C. 20251-2200, U.S.A. (Received July 13, 1989; Accepted May 8, 1990) 相似文献