Über die Chemie des Enniatins

Summary Judging by the physical and chemical properties and bacterial spectra, the antibiotic substance, Enniatin, previously isolated from a strain ofFusarium by the authors, appears to be identical with that which was recently reported byCook et al. derived from another strain and designated by them as Lateritiin-I, although the reported empirical formulæ differ. Numerous physical and chemical characteristics of Enniatin and its degradation products are given, and, further, two relatedFusarium antibiotics, here designated as Enniatin B and C, are briefly described.

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Ausgeführt mit einem Beitrag aus den eidg. Arbeitsbeschaffungskrediten.     

用自身血清抗体筛选人肝细胞肝癌抗原

为了从分子水平上筛选肝细胞肝癌抗原，应用作者所在实验室创建的“重组克隆表达抗原的血清学鉴定技术”（ＳＥＲＥＸｓｅｒｏｌｏｇｉｃａｌｉｎｄｅｎｔｉｆｉｃａｔｉｏｎｏｆａｎｔｉｇｅｎｓｂｙｒｅｃｏｍｂｉｎａｎｔｅｘｐｒｅｓｉｏｎｃｌｏｎｉｎｇ）筛选人肝细胞肝癌（ＨＣＣ）组织构建的ｃＤＮＡ文库，发现了许多与病人，自身血清高滴度抗体反应的克隆。应用多种异体（其他ＨＣＣ病人，多种非ＨＣＣ肿瘤病人，Ｂ型、Ｃ型病毒性肝炎病人，肝硬化病人以及健康人）血清反应分析表明，高滴度抗体反应多数出现在ＨＣＣ病人。参照基因库寻找这些克隆的同源结构，发现其中许多抗原为至今未知基因所编码。进一步的血清和抗原分子分析将为ＨＣＣ特异免疫治疗和诊断提供基础资料     

中国古代园林空间模式研究——以甘泉宫、武侯墓和黄帝陵为例

借鉴空间理论的有关研究成果,依据空间的2种表现形式即感知空间与认知空间的特征,对园林的空间模式进行了界定与研究,并以汉代园林3大遗产地甘泉宫、武候墓和黄帝陵为例进行实地考察,综合分析.研究结果表明,中国古代园林存有外向型、内向型及内外结合型3种空间模式;外向型是一种开放式的空间模式,其表现为"宽广"与"博大";内向型是一种闭合式的空间模式,其表现为"藏风聚气";内外结合型空间模式是上述2种空间模式的结合.研究揭示出园林空间是一个融合统一的有机整体,提示了园林的空间特征与本质,并为中国古代园林或遗产地的空间鉴赏与旅游开发提供新的思路与依据.     

Attosecond metrology.

The generation of ultrashort pulses is a key to exploring the dynamic behaviour of matter on ever-shorter timescales. Recent developments have pushed the duration of laser pulses close to its natural limit-the wave cycle, which lasts somewhat longer than one femtosecond (1 fs = 10-15 s) in the visible spectral range. Time-resolved measurements with these pulses are able to trace dynamics of molecular structure, but fail to capture electronic processes occurring on an attosecond (1 as = 10-18 s) timescale. Here we trace electronic dynamics with a time resolution of 相似文献   

Novel approaches to the treatment of small-cell lung cancer

Small-cell lung cancer (SCLC) is characterized by its initial responsiveness to chemotherapy and the appearance of early metastases. Although combination chemotherapy, in some instances together with radiation, has improved the prognosis of this disease, in most patients SCLC ultimately recurs in a drug-resistant form. Several new strategies for the eradication of SCLC are being explored at the preclinical level. The identification of selective target molecules on the surface of SCLC cells, together with the progress made in antibody engineering, have provided new generations of antibodies and immunoconjugates as well as growth factor antagonists and inhibitors. In addition, recent advances in understanding the biology of SCLC have stimulated new investigations searching to counter the molecular basis underlying the increased proliferation and the apoptosis deficiency of SCLC cells. This can be achieved using antisense oligodeoxynucleotides that repress the expression of growth factor receptors and anti-apoptosis genes, or by gene replacement to compensate for the loss or inactivation of tumor suppressor genes.     

Initial corrosion observed on the atomic scale

Corrosion destroys more than three per cent of the world's GDP. Recently, the electrochemical decomposition of metal alloys has been more productively harnessed to produce porous materials with diverse technological potential. High-resolution insight into structure formation during electrocorrosion is a prerequisite for an atomistic understanding and control of such electrochemical surface processes. Here we report atomic-scale observations of the initial stages of corrosion of a Cu3Au111 single crystal alloy within a sulphuric acid solution. We monitor, by in situ X-ray diffraction with picometre-scale resolution, the structure and chemical composition of the electrolyte/alloy interface as the material decomposes. We reveal the microscopic structural changes associated with a general passivation phenomenon of which the origin has been hitherto unclear. We observe the formation of a gold-enriched single-crystal layer that is two to three monolayers thick, and has an unexpected inverted (CBA-) stacking sequence. At higher potentials, we find that this protective passivation layer dewets and pure gold islands are formed; such structures form the templates for the growth of nanoporous metals. Our experiments are carried out on a model single-crystal system. However, the insights should equally apply within a crystalline grain of an associated polycrystalline electrode fabricated from many other alloys exhibiting a large difference in the standard potential of their constituents, such as stainless steel (see ref. 5 for example) or alloys used for marine applications, such as CuZn or CuAl.     

Emerging connections between DNA methylation and histone acetylation

Modifications of both DNA and chromatin can affect gene expression and lead to gene silencing. Evidence of links between DNA methylation and histone hypoacetylation is accumulating. Several proteins that specifically bind to methylated DNA are associated with complexes that include histone deacetylases (HDACs). In addition, DNA methyltransferases of mammals appear to interact with HDACs. Experiments with animal cells have shown that HDACs are responsible for part of the repressive effect of DNA methylation. Evidence was found in Neurospora that protein acetylation can in some cases affect DNA methylation. The available data suggest that the roles of DNA methylation and histone hypoacetylation, and their relationship with each other, can vary, even within an organism. Some open questions in this emerging field that should be answered in the near future are discussed.